Abstracts (alphabetical according to primary author):

Author statistics

1. L. Ahrens, Evolution of AGS Betatron Tune Measurement System to Meet the Demands of Polarized Proton Acceleration with Strong Partial Snakes for RHIC Injection L. Ahrens, M. Bai, J. Laster
   Maintaining beam polarization throughout the Brookhaven AGS acceleration cycle requires holding the beam betatron tunes very near (dQ < .01) integer values in the presence of serious time dependent lattice distortions introduced by the strong helical partial snake magnets. Frequent and accurate measurements of tunes and tune spreads are necessary to accomplish this. The system for tune measurement in the AGS has been upgraded to allow automatic measurements of tunes and tune spreads to be made in a robust fashion throughout the acceleration cycle. The new system includes the use of an iterative combination of Fourier transformations and turn-by-turn fitting to cope with the wide range of chromaticities encountered during the cycle. A description of the system as well as some typical measurements produced by the system will be given. (characters:846)
   
   
2. J. Alessi, High-Performance EBIS for RHIC (INIVITED) J. Alessi
   An Electron Beam Ion Source (EBIS) source, capable of producing high charge states and high beam currents of any heavy ion species in short pulses, is ideally suited for injection into a synchrotron. An EBIS-based, high current, heavy ion preinjector is now being built at Brookhaven to provide increased capabilities for the Relativistic Heavy Ion Collider (RHIC), and the NASA Space Radiation Laboratory (NSRL). Benefits of the new preinjector include the ability to produce ions of any species, fast switching between species to serve the simultaneous needs of multiple programs, and lower operating and maintenance costs. A state-of-the-art EBIS, operating with an electron beam current of up to 10 A, and producing multi-milliamperes of high charge state heavy ions, has been developed at Brookhaven, and has been operating very successfully on a test bench for several years. The present performance of this high-current EBIS will be presented, along with details of the design of the scaled-up EBIS for RHIC, and the status of its construction. Other aspects of the project, including design and construction of the heavy ion RFQ, Linac, and matching beamlines, will also be mentioned. (characters:1193)
   
   
3. J. Alessi, Design and Performance of the Matching Beamline between the BNL EBIS and an RFQ J. Alessi, E. Beebe, A. Kponou, M. Okamura, A. Pikin, D. Raparia, J. Ritter
   A part of a new EBIS-based heavy ion preinjector, the low energy beam transport (LEBT) section between the high current EBIS and the RFQ is a challenging design, because it must serve many functions. In addition to the requirement to provide an efficient matching between the EBIS and the RFQ, this line must serve as a fast "switchyard", allowing singly charged ions from external sources to be transported into the EBIS trap region, and extracted, highly charged ions to be deflected to off-axis diagnostics (time-of-flight, or emittance). The space charge of the 5-10 mA extracted heavy ion beam is a major consideration in the design. The line includes electrostatic lenses, spherical and parallel-plate deflectors, magnetic solenoid, and diagnostics for measuring current, charge state distributions, emittance, and profile. A prototype of this beamline has been built, and results of tests will be presented. (characters:915)
   
   
4. A. Zhang, A Simplified Approach to Analyze and Model an Inductive Voltage Adder A Simplified Approach to Analyze and Model an Inductive Voltage Adder
   We have recently developed a simplified model and a set of simple formulas for inductive voltage adder design. This model reveals the relationship of output waveform parameters and hardware designs. A computer simulation has demonstrated that parameter estimation based on this approach is accurate as compared to an actual circuit. This approach can be used in early stages of project development to assist feasibility study, geometry selection in engineering design, and parameter selection of critical components. In this paper, we give the deduction of a simplified model. Among the estimation formulas we present are those for pulse rise time, system impedance, and number of stages. Examples are used to illustrate the advantage of this approach. This approach is also applicable to induction LINAC design. (characters:813)
   
   
5. M. Bai, Accelerating Polarized Protons to 250 GeV M. Bai, L. Ahrens, I. G. Alekseev, J. Alessi, J. Beebe-Wang, M. Blaskiewicz, A. Bravar, J. M. Brennan, D. Bruno, G. Bunce, J. Butler, P. Cameron, R. Connolly, J. Delong, T. D'Ottavio, A. Drees, W. Fischer, G. Ganetis, C. Gardner, J.W. Glenn, T. Hayes, H-C. Hseuh, H. Huang, P. Ingrassia, J. Laster, R. Lee, A. Luccio, Y. Luo, W. W. MacKay, Y. Makdisi, G. Marr, A. Marusic, G. McIntyre, R. Michnoff, C. Montag, J. Morris, P. Oddo, B. Oerter, J. Piacentino, F. Pilat, V. Ptitsyn, T. Roser, T. Satogata, K. Smith, D. N. Svirida, D. Trbojevic, N. Tsoupas, J. Tuozzolo, M. Wilinski, S. Tepikian, A. Zaltsman, A. Zelenski, K. Zeno, S. Y. Zhang
   The Relativistic Heavy Ion Collider (RHIC) as the first high energy polarized proton collider was designed to provide polarized proton collisions at a maximum beam energy of 250 GeV. It has been providing collisions at a beam energy of 100 GeV since 2001. Equipped with two full Siberian snakes in each ring, polarization is preserved during the acceleration from injection to 100 GeV with careful control of the betatron tunes and the vertical orbit distortions. However, the intrinsic spin resonances beyond 100 GeV are about a factor of two stronger than those below 100 GeV making it important to examine the impact of these strong intrinsic spin resonances on polarization survival and the tolerance for vertical orbit distortions. Polarized protons were accelerated to the record energy of 250 GeV in RHIC with a polarization of 45% measured at top energy in 2006. The polarization measurement as a function of beam energy also shows the polarization was lost around 136 GeV, the first strong intrinsic resonance above 100 GeV. This paper presents the results and discusses the sensitivity of the polarization survival to orbit distortions. (characters:1147)
   
   
6. M. Bai, Linear Gradient Correction Using An AC Dipole M. Bai, W. Fischer, J. Niedziela, T. Satogata, D. Trbojevic
   Beta functions and phase advances in a storage ring can be measured with an AC dipole. The typical measured beta beating at RHIC in storage conditions is 10-20%. Lower beta* and higher luminosities should be achievable if this beta beating is corrected. This is particularly important for a near-integer RHIC working point, proposed to improve RHIC beam-beam performance. This paper presents simulations and measurement results from correction of RHIC linear optics based on beta beating measured with AC dipoles. (characters:515)
   
   
7. M. Bai, Snake Depolaring Resonance Study in RHIC M. Bai, P. Cameron, A. Luccio, H. Huang, V. Pitisyn, T. Roser, S. Tepikian
   Snake depolarzing resonances due to the imperfect cancellation of the accumulated perturbations on the spin precession between snakes were observed at the Relativistic Heavy Ion Collider (RHIC). During the RHIC 2005 and 2006 polarized proton runs, we mapped out the spectrum of odd order snake resonance at Qy = 7/10 . Here, Qy is the beam vertical betatron tune. We also studied the beam polarization after crossing the 7/10th resonance as a function of resonance crossing rate. This paper reports the measured resonance spectrum as well as the results of resonance crossing. (characters:577)
   
   
8. M. Bai, Design of RHIC Spin Flipper M. Bai, T. Roser
   Full spin flip in the presence of full Siberian snake has been achieved by using an rf dipole or solenoid as spin flipper. This technique requires one to change the snake configuration to move the spin tune away from half integer. However, this is not practical for an operational high energy polarized proton collider like RHIC where beam lifetime is sensitive to small betatron tune change. An new technique of achieving full spin flip with the spin tune staying at half integer is proposed. This paper presents the design of RHIC spin flipper along with simulation results. (characters:577)
   
   
9. J. Beebe-Wang, Realistic Non-linear Model and Field Quality Analysis in RHIC Interaction Regions J. Beebe-Wang and A. Jain
   The existence of multipolar components in the dipole and quadrupole magnets is one of the factors limiting the beam stability in RHIC operations. So, a realistic non-linear model is crucial for understanding the beam behavior and to achieve the ultimate performance in RHIC. A procedure is developed to build a non-linear model using the available multipolar component data obtained from measurements of RHIC magnets. We first discuss the measurements performed at different stages of manufacturing of the magnets in relation to their current state in RHIC. We then describe the procedure to implement these measurement data into tracking models, including the implementation of the multipole feed down effect due to the beam orbit offset from the magnet center. Finally, the field quality analysis in the RHIC interaction regions is presented. (characters:845)
   
   
10. J. Beebe-Wang, Emittance Growth Due to the Beam-Beam Effect in RHIC J. Beebe-Wang
    The beam-beam interaction has a significant impact on the beam emittance growth and the luminosity lifetime in RHIC. A simulation study of the emittance growth was performed using the Lifetrac code. The operational conditions of RHIC 2006 100GeV polarized proton run were used in the study. In this paper, the result of this study is presented and compared to the experimental measurements. (characters:392)
    
    
11. I. Ben-Zvi, Status of the R&D Towards Electron Cooling of RHIC I. Ben-Zvi, D. Barton, D. Beavis, M. Blaskiewicz, J. M. Brennan, A. Burrill, R. Calaga, P. Cameron, X. Chang, A. Drees, A. Fedotov, W. Fischer, D. M. Gassner, J. Grimes, H. Hahn, A. Hershcovitch, H.-C. Hseuh, D. Kayran, J. Kewisch, R. Lambiase, D. Lederle, V. N. Litvinenko, W. Mackay, G. McIntyre, G. Mahler, W. Meng, T. Nehring, C.-I. Pai, G. Parzen, D. Pate, D. Phillips, E. Pozdeyev, B. Oerter, T. Rao, J. Reich, T. Roser, A. Ruggiero, T. Russo, C. Schultheiss, Z. Segalov, J. Smedley, K. Smith, S. Tepikian, D. Trbojevic, J. Tuozzolo, G.. Wang, Q. Wu, K. Yip, A. Zaltsman, H. Bluem, M. Cole, A. Favale, D. Holmes, J. Rathke, T. Schultheiss, A. M. M. Todd, A. Burov, S. Nagaitsev, L. Prost, A. Shemyakin, A. Sidorin, A. Smirnov, Y. Derbenev, P. Kneisel, J. Mammosser, L. Phillips, J. P. Preble, C. Reece, R. Rimmer, J. Saunders, M. Stirbet, H. Wang, G. Bell, D. Bruhwiler, R. Busby, J. Cary, D. Dimitrov, P. Messmer, D. Smithe, and P. Stoltz
    The physics interest in a luminosity upgrade of RHIC requires the development of a cooling-frontier facility. Detailed cooling calculations have been made to determine the efficacy of electron cooling of the stored RHIC beams. This has been followed by beam dynamics simulations to establish the feasibility of creating the necessary electron beam. Electron cooling of RHIC at collisions requires electron beam energy up to about 54 MeV at an average current of between 50 to 100 mA and a particularly bright electron beam. The accelerator chosen to generate this electron beam is a superconducting Energy Recovery Linac (ERL) with a superconducting RF gun with a laser-photocathode. An intensive experimental R&D program engages the various elements of the accelerator: Photocathodes of novel design, superconducting RF electron gun of a particularly high current and low emittance, a very high-current ERL cavity and a demonstration ERL using these components. (characters:966)
    
    
12. M. Blaskiewicz, A Multipurpose Coherent Instability Simulation Code M. Blaskiewicz
    A multipurpose coherent instability simulation code has been written, documented, and released for use. TRANFT (tran-eff-tee) uses fast Fourier transforms to model transverse wakefields, transverse detuning wakes and longitudinal wakefields in a computationally efficient way. Dual harmonic RF allows for the study of enhanced synchrotron frequency spread. When coupled with chromaticity, the theoretically challenging but highly practical post head-tail regime is open to study. Detuning wakes allow for transverse space charge forces in low energy hadron beams and a switch allowing for radiation damping makes the code useful for electrons. (characters:644)
    
    
13. M. Blaskiewicz , Stochastic Cooling of High-Energy Bunched Beams (INVITED TALK) M. Blaskiewicz, J.M. Brennan
    Stochastic cooling of high-energy bunched beams has been achieved in the Relativistic Heavy Ion Collider (RHIC). The physics and technology of the longitudinal cooling system are discussed, and plans for a transverse cooling system are outlined. (characters:246)
    
    
14. J.M. Brennan, Signal Processing with Fiber Optic Technology for the RHIC Stochastic Cooling System J.M. Brennan and M. Blaskiewicz
    Fiber Optic technology is used extensively in the RHIC stochastic cooling system for low level signal processing and the transmission of high frequency and high bandwidth signals over long distances. Amplitude modulated light at 1550 nm can provide constant phase and amplitude across the 5 to 9 GHz band of the cooling system, but for long fibers dispersion at the optical wavelength can compromise the fidelity. Three different modulation techniques for the light source laser have been investigated; external, direct, and electro-absorption modulation. Their relative merits are compared. Differential photo-diodes are used to detect the modulation and realize wideband one and two-turn-delay correlator filters. (characters:716)
    
    
15. Kevin A. Brown, The Bare AGS Tunes and Chromaticities Kevin A. Brown, Leif Ahrens, Joseph W. Glenn, Margaret Harvey, Wuzheng Meng, Paul Menga, Vincent Schoefer, Nicholaos Tsoupas
    In this report we will present recent high precision measurements of the bare AGS tunes and chromaticities, including effects due to eddy currents, and comparisons to the best model of the AGS we have been able to develop. The original AGS model was based on magnetic measurements of representative AGS magnets. Magnetic models of the AGS magnets have shown relatively good agreement with the magnetic measurements, but recently we have done more detailed 3-dimensional analysis of the magnetic models and will present the results of this analysis. This work is motivated by our need to improve our understanding of the AGS lattice when configured for polarized protons with two partial snakes in the lattice. In this configuration we need to operate the vertical betatron tune very close to the integer, in order to avoid depolarization from intrinsic resonances. To avoid coupling resonances we plan to operate the horizontal tune near the integer, requiring an even finer understanding of the AGS lattice. (characters:1009)
    
    
16. Kevin A. Brown, Implementation of an On-line Model for the AGS Controls System Kevin A. Brown, Leif Ahrens, Mei Bai, Jonathan Laster, Nikolay Malitsky, John Morris, Jennifer Niedziela, Todd Satogata, Vincent Schoefer, Joseph Skelly, Nicholaos Tsoupas
    In this report we will present the first results of an on-line model system for the AGS in which a centralized model interface has been developed to provide beam parameters to existing AGS applications. The AGS controls system includes several legacy applications for controlling power supply parameters and for obtaining measurement data from instrumentation. These applications span generations of control systems and typically use highly simplified internal models of the AGS. A primary goal of this project is to centralize the accelerator model of the AGS so that all applications obtain accelerator parameters from a common source. This enabled us to develop an environment that allows combination of on-line and off-line analysis using measured accelerator parameters. This effort includes implementing on-line methods for performing AGS orbit response matrix analysis. (characters:877)
    
    
17. K. Brown, Tune Ripple Measurements at RHIC K. Brown, M. Blaskiewicz, D. Bruno, P. Cameron, A. DellaPenna, W. Fischer, C. Schultheiss
    Tune ripple and nonlinear magnetic fields have been demonstrated to impact collider performance and limit dynamic aperture. Future luminosity goals at the Relativistic Heavy Ion Collider (RHIC) require an increased beam-beam tuneshift parameter, and with it an understanding of tune ripple sources at RHIC. We present tune ripple measurements at RHIC from various systems, including Schottky measurements with gold ions during Run-7. (characters:435)
    
    
18. D. Bruno, RHIC Power Supplies-Failure Statistics for Runs 4, 5 and 6 D. Bruno, G. Ganetis, J. Sandberg, W. Louie, G. Heppner, C. Schultheiss
    The two rings in the Relativistic Heavy Ion Collider (RHIC) require a total of 933 power supplies to supply current to highly inductive superconducting magnets. Failure statistics for the RHIC power supplies will be presented for the last three RHIC runs. The failures of the power supplies will be analyzed. The statistics associated with the power supply failures will be presented. Comparisons of the failure statistics for the last three RHIC runs will be shown. Improvements that have increased power supply availability will be discussed. Further improvements to increase the availability of the power supplies will also be discussed. (characters:641)
    
    
19. D. Bruno, Overview of the AGS Cold Snake Power Supplies and the new RHIC Sextupole Power Supplies D. Bruno, G. Ganetis, J. Sandberg, W. Louie
    The two rings in the Relativistic Heavy Ion Collider (RHIC) were originally constructed with 24 sextupole power supplies, 12 for each ring. Before the start of Run 7, 24 new sextupole power supplies were installed, 12 for each ring. Individual sextupole power supplies are now each connected to six sextupole magnets. A superconducting snake magnet and power supplies were installed in the Alternating Gradient Synchrotron (AGS) and commissioned during RHIC Run 5, and used operationally in RHIC Run 6. The power supply technology, connections, control systems and interfacing with the Quench Protection system for both these systems will be presented. (characters:653)
    
    
20. A. Burrill, Multipacting Analysis of a quarter wave choke joint used for insertion of a demountable cathode into a SRF photoinjector A. Burrill, I. Ben-Zvi, M. Cole, J. Rathke, P. Kneisel, R. Rimmer, R. Manus, G. Wu
    The multipacting phenomena in accelerating structures and coaxial lines are well documented and methods of mitigating or suppressing it are understood. The multipacting that occurs in a quarter wave choke joint designed to mount a cathode insertion stalk into a superconducting RF photoinjector has been analyzed via calculations and experimental measurements and the effect of introducing multipacting suppression grooves into the structure is analyzed. Several alternative choke joint designs are analyzed and suggestions made regarding future choke joint development. Furthermore, the problems encountered in cleaning the choke joint surfaces, factors important in changes to the secondary electron yield, are discussed and evaluated. This design is being implemented on the BNL 1.3 GHz photoinjector, previously used for measurement of the quantum efficiency of bare Nb, to allow for the introduction of other cathode materials for study, and to verify the design functions properly prior to constructing our 703 MHz photoinjector with a similar choke joint design. (characters:1070)
    
    
21. A. Burrill, Challenges encountered during the processing of the BNL ERL 5 cell accelerating cavity A. Burrill, I. Ben-Zvi, R. Calaga, H. Hahn, V. N. Litvinenko, G. McIntyre, P. Kneisel, J. Mammosser, J. P. Preble, C. Reece, R. Rimmer, J. Saunders
    One of the key components for the Energy Recovery Linac being built by the Electron cooling group in the Collider Accelerator Department is the 5 cell accelerating cavity which is designed to accelerate 2 MeV electrons from the gun up to 15-20 MeV, allow them to make one pass through the ring and then decelerate them back down to 2 MeV prior to sending them to the dump. This cavity was designed by BNL and fabricated by AES in Medford, NY. Following fabrication it was sent to Thomas Jefferson Lab in VA for chemical processing, testing and assembly into a string assembly suitable for shipment back to BNL and integration into the ERL. The steps involved in this processing sequence will be reviewed and the deviations from processing of similar SRF cavities will be discussed. The lessons learned from this process are documented to help future projects where the scope is different from that normally encountered. (characters:920)
    
    
22. R. Calaga, Compensation of the 2/3rd resonance in RHIC using IR correctors R. Calaga, M. Bai, W. Fischer, Y. Luo
    Compensation of the horizontal 2/3rd resonance is desirable to increase the luminosity in RHIC due to its proximity to the current working point for protons. Results from beam experiments during 2006 to compensate the 3rd order resonances using two pairs of IR sextupole correctors are presented. Simulations for effective compensation using all six pairs of IR sextupole correctors is also discussed. (characters:402)
    
    
23. R. Calaga, Localizing sources of horizontal orbit oscillations at RHIC R. Calaga, R. Michnoff, T. Satogata
    Horizontal oscillations of the closed orbit at frequencies around 10Hz are observed at RHIC. These oscillations lead to beam beam offsets at the collision point, resulting in emittance growth and reduced luminosity. An approach to localize the sources of these vibrations using a special mode of RHIC turn-by-turn BPM data is presented. Data from the 2005 Cu-Cu and pp runs is analyzed to spatially resolve the location of the dominant sources. (characters:446)
    
    
24. R. Calaga, BPM calibration independent LHC optics correction R. Calaga, R. Tomas, M. Giovannozzi, F. Zimmermann
    The tight mechanical aperture for the LHC imposes severe constraints on both the beta and dispersion beating. Robust techniques to compensate these errors are critical for operation of high intensity beams in the LHC. Realistic simulations of measurement and correction show that the use of BPM calibration and model independent observables is a key ingredient to accomplish optics correction. Experiments at RHIC to benchmark the algorithms for optics correction are also presented. (characters:485)
    
    
25. R. Calaga, Small angle crab compensation for LHC IR upgrade R. Calaga, U. Dorda, K. Ohmi, K. Oide, R. Tomas, F. Zimmermann
    A small angle (< 1mrad) crab scheme is an attractive option for the LHC luminosity upgrade to recover the geometric luminosity loss from the finite crossing angle, which steeply increases to unacceptable levels as the IP beta function is reduced below its nominal value. The crab compensation in the LHC can be accomplished using only two sets of deflecting rf cavities, placed in collision-free straight sections of LHC to nullify the crossing angles at IP1 & IP5. We present IR optics configurations with low-angle crab crossing, study the beam-beam performance and proton-beam emittance growth in the presence of crab compensation, lattice errors, crab RF noise sources. We also explore a 400MHz superconducting cavity design and discuss the pertinent RF challenges. (characters:771)
    
    
26. P. Cameron , Progress in Tune, Coupling, and Chromaticity Measurement and Feedback during RHIC Run 7 P. Cameron, A. DellaPenna, L. Hoff, Y. Luo, A. Marusic, C. Schultheiss, S. Tepikian, A. Boccardi, M. Gasior, R. Jones, K. Kasinski, R. Steinhagen, C.Y. Tan
    Tune feedback was first implemented in RHIC in 2002, as a specialist activity. The transition of the tune feedback system to full operational status was impeded by dynamic range problems, as well as by overall loop instabilities driven by large coupling. The dynamic range problem was solved by the CERN development of the Direct Diode Detection Analog Front End. Continuous measurement of all projections of the betatron eigenmodes made possible the world's first implementation of coupling feedback during beam acceleration, resolving the problem of overall loop instabilites. Simultaneous tune and coupling feedbacks were utilized as specialist activities for ramp development during the 2006 RHIC run. At the beginning of the 2007 RHIC run there remained two obstacles to making these feedbacks fully operational in RHIC - chromaticity measurement and control, and the presence of strong harmonics of the power line frequency in the betatron spectrum. We report here on progress in tune, coupling, and chromaticity measurement and feedback, and discuss the relevance of our results to the LHC commissioning effort. The results of investigations of power line harmonics in RHIC are presented elsewhere in these proceedings. (characters:1227)
    
    
27. P. Cameron, Investigation of Power Line Harmonics in the Betatron Spectrum at RHIC P. Cameron, A. Dellapenna, J. Sandberg, C. Schultheiss
    Direct excitation of the betatron resonance by high harmonics of the power line frequency has been observed at RHIC, at the Tevatron, and at the CERN PS and SPS. At RHIC, these harmonics are as much as 40dB above the noise floor of the phase-locked loop tune measurement system at injection and store, and as much as 80dB above the noise floor during acceleration ramps. They are an obstacle to the operational implementation of tune, coupling, and chromaticity feedback at RHIC, and may contribute to unexplained emittance growth seen in RHIC during acceleration ramps. We report on recent observations, and on investigations into the possible causes and cures of this phenomenon. (characters:682)
    
    
28. A. Drees, Summary of RHIC Performance during the FY07 Heavy Ion Run A. Drees, L. Ahrens, J. Alessi, M. Bai, D. Barton, J. Beebe-Wang, M. Blaskiewicz, M. Brennan, D. Bruno, J. Butler, P. Cameron, R. Connolly, T. D'Ottavio, W. Fischer, W. Fu, G. Ganetis, J.W. Glenn, T. Hayes, H.-C. Hseuh, H. Huang, R. Lee, Y. Luo, W. MacKay, G. Marr, A. Marusic, R. Michnoff, C. Montag, J. Morris, B. Oerter, F. Pilat, V. Ptitsyn, T. Roser, J. Sandberg, T. Satogata, C. Schultheiss, K. Smith, S. Tepikian, D. Trbojevic, N. Tsoupas, J. Tuozzolo, A. Zaltsman, S.Y. Zhang
    After the last successful RHIC Au-Au run in 2004 (Run-4), RHIC experiments now require significantly enhanced luminosity to study very rare events in heavy ion collisions. RHIC has demonstrated its capability to operate routinely above its design average luminosity per store of 2x10^26 cm^-2 s^-1. In Run-4 we already achieved 2.5 times the design luminosity in RHIC. This luminosity was achieved with only 40% of bunches filled, and with beta* = 1 m. However, the goal is to reach 4 times the design luminosity, 8x10^26 cm^-2 s^-1, by reducing the beta* value and increasing the number of bunches to the accelerator maximum of 111. In addition, the average time in store should be increased by a factor of 1.1 to about 60% of calendar time. We present an overview of the changes that increased the instantaneous luminosity and luminosity lifetime, raised the reliability, and improved the operational efficiency of RHIC Au-Au operations during Run-7. (characters:954)
    
    
29. A. Drees, Multi-bunch Instability Monitoring at RHIC* A. Drees, M. Blaskiewicz, R. Lee
    Transition Crossing with heavy ions is one of the challenges of RHIC's high intensity operation, likely triggering various bunch-to-bunch and intra-bunch instabilities. While the centroid position of the largest intensity bunch was routinely monitored in RHIC before the heavy ion run in 2007 (Run-7), there was no monitoring in place of all bunches with a granularity that would allow measurements of intra-bunch instabilites. RHIC now employs four wide band button pickups, two horizontal and two vertical in each ring, as instability monitors. A deep memory oscilloscope is used for data acquisition, providing several samples along the 10 ns long bunches for all bunches and many revolutions around transition crossing. The data is automatically triggered and archived for every transition crossing. Measurements from Run-7 are shown, compared to simulations and analyzed. (characters:878)
    
    
30. A. Drees, Bunch-to-bunch Luminosity Monitoring in RHIC A. Drees, L. Hoff, H. Crawford
    Various effects can cause non-uniform transverse emittance growth along the bunch train in RHIC, including electron-cloud triggered instability near transition crossing. One indication of such an instability is an inhomogeneous luminosity contribution from the individual colliding bunch pairs in one revolution. Until now, luminosity monitoring at RHIC only provided a collision rate signal that integrated over all bunches in the ring. In the 2007 RHIC heavy ion run (Run-7), a bunch-to-bunch luminosity monitor was commissioned that allows monitoring of the collision and experimental background signals on a bunch-to-bunch basis. This report presents the monitoring system and discusses first results from Run-7. (characters:718)
    
    
31. A. Drees, Abort Gap Cleaning with High Intensity Beams in RHIC A. Drees, R. Michnoff, W. Fu
    Switching from the 28 MHz RHIC acceleration RF system to the 200 MHz storage system causes a higher debunching rate of heavy ion beams, and amplification of debunching from other mechanisms. At the end of a four hour store, debunched beam can easily account for more than 30% of the total beam intensity. To avoid magnet quenches and experimental detector damage at the time of beam dump, it is desirable to avoid any accumulation of debunched beam from the beginning of each store. A combination of a fast transverse kicker and a 2-stage transverse collimator system is used to clean the abort gap continuously throughout the store with an increased repetion rate compared to previous years. The increase in repetion rate is necessary to deal with bunch intensities of more than 1.4x10^11 ions. This report summarizes the system upgrades and reports on the achieved cleaning performance with and without the presence of stochastic cooling. (characters:942)
    
    
32. A. Drees, Longitudinal Collision Area Measurements at RHIC A. Drees, S. Nemesure, C. Pinkenburg, R. Lee
    With increased luminosity demands from RHIC experiments, management of longitudinal collision area in the interaction regions has became progressively more important. The discrepancy between recorded luminosity (collisions occurring within the most central detector components) and delivered luminosity (collisions ocurring anywhere along the overlap region of the two circulating bunches) ranges up to 40% depending on details of a given detector. A 196 MHz storage RF system is used in RHIC to create and maintain short bunches. Online vertex monitoring from the experiments allows immediate quality control of the longitudinal collision area including the width of the distribution and the center position of the collision area. A graphical interface was developed for immediate display of the vertex distributions in the RHIC main control room. Data from the PHENIX detector are shown and discussed and compared to wall current monitor measurements of the two beams. (characters:972)
    
    
33. A.V. Fedotov, RHIC plans towards higher luminosity (INVITED TALK) A.V. Fedotov
    The Relativistic Heavy Ion Collider (RHIC) is designed to provide luminosity over a wide range of beam energies and species, including heavy ions, polarized protons, and asymmetric beam collisions. In the first seven years of operation there has been a rapid increase in the achieved peak and average luminosity, substantially exceeding design values. Work is presently underway to achieve the Enhanced Design parameters in about 2008. Planned major upgrades include the Electron Beam Ion Source (EBIS), the RHIC-II electron cooling upgrade, and construction of an electron-ion collider (eRHIC). We review the expected RHIC upgrade performance. Electron cooling and its impact on the luminosity at various collision energies both for heavy ions and protons are discussed in detail. (characters:782)
    
    
34. A.V. Fedotov, Electron cooling in the presence of undulator fields A.V. Fedotov, I. Ben-Zvi, D. Kayran, V.N. Litvinenko, G. Bell, D.L. Bruhwiler, A. Sidorin, A. Smirnov
    The traditional electron cooling system used in low-energy coolers employs an electron beam immersed in a longitudinal magnetic field. In the first relativistic cooler, which was recently commissioned at Fermilab, the friction force is dominated by the non-magnetized collisions between electrons and antiprotons. The design of the higher-energy cooler for Relativistic Heavy Ion Collider (RHIC) recently adopted a non-magnetized approach which requires a low temperature electron beam. However, to avoid significant loss of heavy ions due to recombination with electrons in the cooling section, the temperature of the electron beam should be very high. These two contradictory requirements are satisfied in the design of the RHIC cooler with the help of the undulator fields. The model of the friction force in the presence of an undulator field was benchmarked vs direct numerical simulations with an excellent agreement. Simulations of ion beam dynamics in the presence of such a cooler and helical undulator is discussed in detail, including recombination suppression and resulting luminosities. (characters:1100)
    
    
35. A.V. Fedotov, High-energy electron cooling based on realistic six-dimensional distribution of electrons A.V. Fedotov, I. Ben-Zvi, D. Kayran, A. Sidorin, A. Smirnov
    The traditional electron cooling system employed at low-energy coolers is based on an electron beam generated with an electrostatic electron gun in DC operating mode, immersed in a longitudinal magnetic field of a solenoid. The coupling of the horizontal and vertical motion allows representation of the friction force as a sum of the transverse and longitudinal components. The analytic treatment proceeds by allowing several approximations, for example, uniform transverse density distribution of electron beam and Maxwellian distribution in the velocity space. The high-energy electron cooling system for RHIC is unique compared to standard coolers. It requires bunched electron beam. Electron bunches are produced by an Energy Recovery Linac (ERL), and cooling is planned without longitudinal magnetic field. To address unique features of the RHIC cooler, a generalized 3-D treatment of cooling force was introduced in BETACOOL code which allows to calculate friction force from an arbitrary six-dimensional distribution of the electrons. Results based on this treatment are compared to typical approximations. Simulations for RHIC cooler based on realistic electron distribution from ERL are presented. (characters:1208)
    
    
36. W. Fischer, E-cloud experiments at RHIC W. Fischer, M. Blaskiewicz, H. Huang, H.C. Hseuh, U. Iriso, V. Ptitsyn, T. Roser, D. Trbojevic, P. Thieberger, J. Wei, S.Y. Zhang
    Since 2001 RHIC has experienced electron cloud effects, which have limited the beam intensity. These include dynamic pressure rises - including pressure instabilities, a reduction of the stability threshold for bunches crossing the transition energy, and possibly slow emittance growth. We report on the main observations in operation and dedicated experiments, as well as the effect of various countermeasures including baking, NEG coated warm pipes, pre-pumped cold pipes, bunch patterns, scrubbing, and anti-grazing rings. (characters:526)
    
    
37. W. Fischer, Experiments with a DC wire in RHIC W. Fischer, R. Calaga, U. Dorda, J.-P. Koutchouk, F. Zimmermann, T. Sen
    A DC wire has been installed in RHIC to explore the long-range beam-beam effect, and test its compensation. We report on experiments that measure the effect of the wire's electro-magnetic field on the beam's lifetime and tune distribution, and accompanying simulations. (characters:271)
    
    
38. W. Fischer, Transverse Beam Transfer Functions of colliding beams in RHIC W. Fischer, M. Blaskiewicz, R. Calaga, P. Cameron, W. Herr, T. Pieloni
    We use transverse beam transfer functions to measure tune distributions of colliding beams in RHIC. The tune has a distribution due to the beam-beam interaction, nonlinear magnetic fields - particularly in the interaction region magnets, and non-zero chromaticity in conjunction with momentum spread. The measured tune distributions are compared with calculations. (characters:365)
    
    
39. C.J. Gardner, Setup and Performance of the RHIC Injector Accelerators for the 2007 Run with Gold Ions C.J. Gardner, L. Ahrens, J. Alessi, J. Benjamin, M. Blaskiewicz, J.M. Brennan, K.A. Brown, C. Carlson, J.W. Glenn, M. Harvey, T. Hayes, Haixin Huang, W.W. Mackay, G. Marr, J. Morris, F. Pilat, T. Roser, F. Severino, K.S. Smith, D. Steski, P. Thieberger, N. Tsoupas, A. Zaltsman, K. Zeno
    Gold ions for the 2007 run of the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) are accelerated in the Tandem, Booster and AGS prior to injection into RHIC. The setup and perfomance of this chain of accelerators will be reviewed with a focus on improvements in the quality of beam delivered to RHIC. In particular, more uniform stripping foils between Booster and AGS, and a new bunch merging scheme in AGS promise to provide beam bunches with reduced longitudinal emittance for RHIC. (characters:518)
    
    
40. J. Gullotta, RHIC BPM Calibration Algorithm J. Gullotta, C. Dawson, C. Degen, R. Michnoff, T. Russo, T. Satogata
    Testing and Implementation Improving reliability and reproducibility in the RHIC beam position monitor (BPM) system has been the focus of a significant and ongoing effort at Brookhaven National Laborotory. Following a system-wide hardware modification during the summer of 2005, we have implemented improvements to the software architecture for calibrating the electronics. In this paper, we present an improved calibration algorithm, with results from bench tests to demonstrate insensitivity to temperature variations, component drift, and common mode amplitude of calibration signals. (characters:590)
    
    
41. H. Hahn, Ferrite-lined HOM absorber for the e-Cool ERL H. Hahn, A. Blednykh, L. Hammons, and D. Kayran
    An R&D facility for an Energy Recovery Linac (ERL) intended as part of the "Electron-Cooling Xperiment" for RHIC is being constructed at this laboratory. The center piece of the project is the experimental 5-cell 703.75 MHz superconducting ECX cavity. Successful operation will depend on effective HOM suppression, and it is planned to achieve HOM damping exclusively with room temperature ferrite absorbers. A ferrite-lined pillbox model with dimensions reflecting the operational unit was assembled, and the cavity resonances and quality factors were determined from scattering coefficient measurements and were interpreted as surface impedance. Results from a 5-cell copper cavity with an attached ferrite absorber prototype are used for the prediction of the ECX cavity HOM damping. A rotational symmetric ferrite-lined pillbox was analyzed theoretically and compared with the simulation codes Micro Wave Studio, GdfidL, and Superfish. Discrepancies of the resonance frequencies and Q-values were found, and steps to reach agreement are discussed. (characters:1052)
    
    
42. Y. Hao, Studies of Electron-Proton Beam-Beam Interactions in eRHIC Y. Hao, V.N. Litvinenko, E. Pozdeyev, V. Ptitsyn
    Beam-beam effects present one of major factors limiting the luminosity of colliders. In the linac-ring option of eRHIC design, an electron beam accelerated in a superconducting energy recovery linac collides with a proton beam circulating in the RHIC ring. There are some features of beam-beam effects which require careful examination in linac-ring configuration. First, the beam-beam interaction can induce specific head-tail type instability of the proton beam referred to as 'kink' instability. Thus, beam stability conditions should be established to avoid proton beam loss. Also, the electron beam transverse disruption by collisions has to be evaluated to ensure beam quality is good enough for the energy recovery pass. In addition, fluctuations of electron beam current and/or electron beam size, as well as transverse offset, can cause proton beam emittance growth. The tolerances for those factors should be determined and possible countermeasures should be developed to mitigate the emittance growth. In this paper, a soft Gaussian strong-strong simulation is used to study all of mentioned beam-beam interaction features and possible techniques to reduce the emittance growth. (characters:1190)
    
    
43. A. Hershcovitch, Plasma Lens for US Based Super Neutrino Beam at Either FNAL or BNL A. Hershcovitch, W. Weng, M. Diwan, J. Gallardo, S. Kahn, H. Kirk, B. Johnson, E. Garate, A. Van Drie, N. Rostoker
    A Plasma lens concept is examined as an alternative to focusing horns and solenoids for the BNL Super Neutrino beam facility. The concept is based on a combined high-current lens/target configuration. Current is fed at an electrode located downstream from the beginning of the target where pion capturing is needed. Some of the current flows through the target, while the rest is carried by plasma outside the target. A second more "conventional" plasma lens section, with an additional current feed, follows the target. Plasma of this section is immersed in a solenoidal magnetic field to facilitate its current profile shaping to optimize pion capture.Simulation of the second section alone yielded a 10% higher neutrino production than the horn system. Plasma lenses have additional advantages: larger axial currents can be generated and sustained. Signal purity: plasma lens minimizes neutrino background during anti-neutrino beam runs. Lens medium consists of plasma, consequently, particle absorption and scattering is minimal compared to other schemes. Withstanding high mechanical and thermal stresses is not a problem in a plasma lens. With recent development of new insulators for radiation machines, surviving prolonged exposure to radiation is no longer a major issue for plasma lenses. Results of capturing and focusing obtained for various plasma lens configurations will be presented. (characters:1400)
    
    
44. H. Huang, Overcoming Depolarizing Resonances in the AGS with Two Helical... H. Huang, L. Ahrens, M. Bai, K.A. Brown, C. Gardner, J.W. Glenn, F. Lin, A.U. Luccio, W.W. MacKay, V. Ptitsyn, T. Roser, J. Takano, S. Tepikian, N. Tsoupas, K. Yip, K. Zeno
    Overcoming Depolarizing Resonances in the AGS with Two Helical... Dual partial snake scheme has provided polarized proton beams with 1.5*1011 intensity and 65% polarization for RHIC spin program. To overcome the residual polarization loss due to horizontal resonances in the AGS, a new string of quadrupoles have been added. The horizontal tune can then be set in the spin tune gap generated by the two partial snakes, such that horizontal resonances can also be avoided. This paper presents the accelerator setup and preliminary results. (characters:539)
    
    
45. D. Kayran, Optics of a two-pass ERL as an electron source for non-magnetized RHIC-II Electron Cooler D. Kayran, I. Ben-Zvi, R. Calaga, X. Chang, J. Kewisch, V. N. Litvinenko, E. Pozdeyev
    Non-magnetized electron cooling of RHIC requires an electron beam energy of 54.3 MeV, electron charge per bunch of 5 nC, normalized rms beam emittance of 4 mm-mrad, and rms energy spread of 3e-04. In this paper we describe a lattice of a two-pass SCRF energy recovery linac (ERL) and results of a PARMELA simulation that provides electron beam parameters satisfying RHIC electron cooling requirements. (characters:402)
    
    
46. D. Kayran, Merger system optimization in BNL's High Current R&D ERL D. Kayran, Vladimir N. Litvinenko
    A super-conducting RF R&D Energy recovery linac (ERL) is under construction at Brookhaven National Laboratory (BNL). This ERL will be used as a test facility to study issues relevant to high-current, high-brightness beams. One of the goals is to demonstrate an electron beam with high charge per bunch (~ 5 nC) and extremely low normalized emittance (~ 5 mm-mrad) at an energy of 20 MeV. In contrast with operational high-brightness linear electron accelerators, all presently operating ERLs have an order of magnitude larger emittances for the same charge per bunch. One reason for this emittance growth is that the merger system mixes transverse and longitudinal degrees of freedom, and consequently violates emittance compensation conditions. A merger system based on zigzag scheme resolves this problem. In this paper we discuss performance of the present design of the BNL R&D ERL injector with a zigzag merger. (characters:917)
    
    
47. J. Kewisch, Emittance Compensation for Magnetized Beams J. Kewisch, X. Chang
    Emittance compensation is a well established technique for minimizing the emittance of electron beam from a RF photo-cathode gun. Longitudinal slices of a bunch have a small emittance, but due to the longitudinal charge distribution of the bunch and time dependent RF fields they are not focused in the same way, so that the direction of their phase ellipses diverges in phase space and the projected emittance is much larger. Emittance compensation reverses the divergence. At the location where the slopes of the phase ellipses coincides the beam is accelerated, so that the space charge forces are reduced. A recipe for emittance compensation is given in [2]. For magnetized beams (where the angular momentum is non-zero) such emittance compensation is not sufficient because variations in the slice radius lead to variations in the angular speed and therefore to an increase of emittance in the rotating frame. We describe a method and tools for a compensation that includes the beam magnetization. (characters:1003)
    
    
48. J. Kewisch, Low Emittance Electron Beams for the RHIC Electron Cooler J. Kewisch, X. Chang
    An electron cooler, based on an Energy Recovery Linac (ERL) is under development for the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. This will be the first electron cooler operating at high energy with bunched beams. In order to achieve sufficient cooling of the ion beams the electron have to have a charge of 5 nC and a normalized emittance less than 4x10-6 m. This paper presents the progress in optimizing the injector and the emittance improvements from shaping the charge distribution in the bunch. (characters:535)
    
    
49. C.J. Liaw, Study of the RHIC BPM SMA Connector Failure Problem C.J. Liaw, R. Sikora and R. Schroeder
    About 730 cryogenic beam position monitors (BPMs) are mounted on the RHIC CQS and triplet superconducting magnets. Semi-rigid coaxial cables bring the electrical signal from BPM feedthroughs to outside flanges at ambient temperature. Each year approximately 10 cables fail during RHIC operations. The connection usually fails at the warm end of the cable, either from solder joint failure or retraction of the center conductor in the SMA connector. Finite element analyses were performed to understand the solder joint failure mechanism. Results showed that (1) the SMA center conductor can separate from the mating connector due to the thermal retraction, (2) the maximum thermal stress at the warm end solder joint can exceed the material strength of the Pb37/Sn63 solder material, and (3) magnet ramping frequency (~10 Hz) during the machine startup can possibly resonate the coaxial cable and damage the solder joint. This failure problem can be resolved by repairing with silver bearing solder material (a higher strength material) and crimping the cable at the locations close to the SMA connector to prevent center conductor retraction. (characters:1144)
    
    
50. F. Lin, Spin Tracking of Polarized Proton Acceleration with Two Partial Siberian Snakes in the AGS F. Lin, L.A. Ahrens, M. Bai, K. Brown, E.D. Courant, J.W. Glenn, H. Huang, S.Y. Lee, A.U. Luccio, W.W. MacKay, T. Roser, N. Tsoupas
    With two strong partial snakes that rotate the spin by less than 180 degrees employed in the AGS synchrotron, the polarization of the polarized proton should be maintained across the acceleration cycle by fully overcoming the imperfection and intrinsic resonances. However, the measured 65% polarization at the end of the acceleration still showed an 11% polarization loss compared to the injected 82% beam polarization. Spin tracking simulations using the realistic AGS lattice also show a similar polarization loss with realistic acceleration rate and betatron tunes. This paper presents the results of the simulations and the possible reasons for the polarization loss. (characters:674)
    
    
51. Fanglei Lin, Dispersion Generated by an Insertion Device and the Effect on the Emittance Fanglei Lin, Weiming Guo
    In this paper we derive the general form of dispersion generated by insertion devices. The effect on the emittance is calculated based on the general form. Some terms in our result are ignored in the present theory; however, they might be significant in the future light sources. (characters:280)
    
    
52. Y. Luo, RHIC Beam-Based Sextupole Polarity Verification Y. Luo, T. Satogata, P. Cameron, A. Dellapenna, D. Trbojevic
    A beam-based method was proposed and applied to check the polarities of the arc sextupoles in the Relativistic Heavy Ion Collider (RHIC) with repetitive local horizontal bumps. Wrong sextupole polarities can be easily identified from mismatched signs and amplitudes of the horizontal and vertical tune shifts from bump to bump and/or from arc to arc. This check takes less than 2 hours for both RHIC Blue and Yellow rings. Tune shifts in both planes during this study were tracked with a high-resolution baseband tunemeter (BBQ) system. This method was successfully used to the sextupole polarity check in the RHIC run06. (characters:622)
    
    
53. Y. Luo, Online Nonlinear Chromaticity Correction Using Off-Momentum Tune Response Matrix Y. Luo, W. Fischer, N. Malisky, S. Tepikian, D. Trobjevic
    With 8 arc sextupole families in each RHIC ring, the nonlinear chromaticities can be corrected on-line by matching the off-momentum tunes onto the wanted off-momentum tunes with linear chromaticity only. The Newton method with singular value decomposition (SVD) technique is used for this multi-dimensional nonlinear optimization, where the off-momentum tune response matrix with respect to sextupole strength changes is adopted to simplify and fasten the on-line optimization process. The off-momentum tune response matrix can be calculated with the on-line accelerator optics model or directly measured with the real beam. This correction method will be verified and used in the coming RHIC run'07. (characters:701)
    
    
54. Y. Luo, Dynamic Aperture Studies for the Current RHIC Polarized Proton Run Optics Y. Luo, M. Bai, J. Beebe-Wang, W. Fischer, A. Jain, C. Montag, T. Roser, S. Tepikian, D. Trobjevic
    To further improve the the polarized proton (pp) luminosity in the Relativistic Heavy Ion Collider, the beta functions at the two interaction points (IPs) will be reduced from 1.0 m to 0.9m in 2007. In addition, it is planned to increase the bunch intensity from 1.5*10^11 to 2.0*10^11. To accommodate these changes, the nonlinear chromaticities and the third resonance driving term should be corrected. In 2007, the number of the arc sextupole power supplies will be doubled from 12 to 24, which allows nonlinear chromaticity correction. With the updated field errors in the interaction regions (IRs), detailed dynamic aperture studies are carried out to optimize the nonlinear correction schemes, and increase the available tune space in collision. (characters:751)
    
    
55. Y. Luo, Measurement and Correction of Third Resonance Driving Term in the RHIC Y. Luo, M. Bai, J. Bengtsson, R. Calaga, W. Fischer, N. Malisky, F. Pilat, T. Satogata
    To further improve the polaried proton (pp) run collision luminoity in the Relativistic Heavy Ion Collider, correction of the horiozntal two-third resonance is desirable to increase the available tune space. The third resonance driving term is mesaured with the turn-by-turn (TBT) beam position monitor (BPM) data with AC dipole excitation. A resonance driving term response matrix based on the optics model is used to on-line compensate the third resonance driving terms while keeping other rsonance driving terms and first order chromaticities unchanged. The results of beam experiment and simulation correction are presented and discussed. (characters:643)
    
    
56. W. W. MacKay, Investigation of Vertical-Longitudinal Coupling in the AGS W. W. MacKay
    During polarized proton running in RHIC with the vertical tune very close to 9, we have seen growth of the vertical emittance. One possible source which could cause emittance growth is a linear growth which should be expected for particles which actually have integer tunes. Another possibility for unstable motion is a sum resonance (Qv+Qsy=integer). Coupling between vertical and longitudinal motion may occur from two sources: "direct" vertical dispersion from vertical bends (quad misalignments), and "indirect" vertical dispersion from horizontal-vertical coupling via solenoidal or rolled quadrupole fields. The "direct" coupling reduces to a 2-d problem with the usual sum resonance generally being unstable and a difference resonance being stable. The "indirect" coupling is a 3-d problem which has not really been explored. At least in some simple simulations it appears that the indirect case may be stable for both sum and difference resonances with small perturbations of transverse coupling. It should be noted that for synchrobetatron coupling, the resonant condition changes from a sum resonance at injection to a difference resonance at extraction as the beam crosses transition if Qv is slightly below an integer. (I. e., the T_56 transport matrix element changes sign across transition.) A proposal for a study with gold ions at injection energy will be discussed. (characters:1383)
    
    
57. W. W. MacKay, Symplectic Modeling of RHIC Snakes and Rotators W. W. MacKay
    Each ring of RHIC has two Siberian snakes and four spin rotators with four helical dipoles in each snake/rotator. Transverse orbit excursions in these magnets can be several centimeters at injection energy. Unlike most magnets in accelerators with transverse fields, the vector potential for a helical dipole must have a helical twist resulting in both transverse and longitudinal components. As such, the Hamiltonian is not separable into separate momenta and coordinate parts: A(p)+V(x,y,z), so the usual symplectic integrators of Ruth or Yoshida are not applicable. In this paper, I describe a symplectic integration of a "hard-edged" vector potential which I have used to model these magnets. I also show how a symplectic interpolation may be used to minimize integrations over a range of momenta. (characters:803)
    
    
58. Y. Makdisi, Absolute Measurement of the Polarization of High Energy Proton Beams at RHIC Y. Makdisi, I. Alekseev, S., A. Bravar, G. Bunce, M.A. Chapman, S. Dhawan, K.O. Eyser, R. Gill, W. Haeberli, H. Huang, Z. Li, A. Khodinov, A. Kponou, W. Meng, A. Nass, H. Okada, N. Saito, S. Resica, E. Stephenson, D. Svirida, T. Wise, K. Yip, A. Zelenski, V. Zubets
    Absolute Measurement of the Polarization of High Energy Proton Beams at RHIC The spin physics program at the Relativistic Heavy Ion Collider (RHIC) requires knowledge of the proton beam polarization to better than 5%. Such a goal is made the more difficult by the lack of knowledge of the analyzing power of high energy nuclear physics processes. To overcome this, a polarized hydrogen jet target was constructed and installed at an intersection region in RHIC where it intersects both beams. The premise is to utilize the precise knowledge of the jet proton beam polarization to measure the analyzing power in the proton - proton elastic scattering process in the Coulomb Nuclear Interference (CNI) region at the prescribed RHIC proton beam energy, then use the reverse reaction to measure the degree of the beam polarization, and finally confront the results with simultaneous measurements taken by the fast high statistics polarimeter that measure the p-Carbon elastic scattering process also in the CNI region to calibrate the latter. (characters:1040)
    
    
59. I. M. Marneris, Simulations of the AGS MMPS Storing Energy in Capacitor Banks I. M. Marneris, V. S. Badea, R. Bonati, T. Roser, J. Sandberg
    The Brookhaven AGS Main Magnet Power Supply (MMPS) is a thyristor control supply rated at 5500 Amps, +/-9000 Volts. The peak magnet power is 50 MWatts. The power supply is fed from a motor/generator manufactured by Siemens. The generator is 3 phase 7500 Volts rated at 50 MVA. The peak power requirements come from the stored energy in the rotor of the motor/generator. The motor generator is about 45 years old and Siemens is not manufacturing similar machines in the future. We are therefore investigating different ways of storing energy for future AGS MMPS operation. This paper will present simulations of a power supply where energy is stored in capacitor banks. Two dc to dc converters will be presented. The switching elements would be IGCT's made by ABB. The simulation program used is called PSIM Version 6.1. The control system of the power supply will also be presented. The average power from the Long Island Power Authority (LIPA) into the power supply will be kept constant during the pulsing of the magnets at +/-50 MW. The reactive power will also be kept constant below 1.5 MVAR. Waveforms will be presented. (characters:1128)
    
    
60. C. Montag, A near-integer working point for polarized protons in RHIC C. Montag, M. Bai, J. Beebe-Wang, R. Calaga, M. Blaskiewicz, W. Fischer, A. Jain, Y. Luo, N. Malitsky, T. Roser, S. Tepikian
    To achieve the RHIC polarized proton enhanced luminosity goal of $150\cdot 10^30\,{\rm cm}^{-2}{\rm sec}^{-1}$ on average in stores at 250\,GeV, the luminosity needs to be increased by a factor of 3 compared to what was achieved in 2006. Since the number of bunches is already at its maximum of 111, limited by the injection kickers and the experiments' time resolution, the luminosity can only be increased by either increasing the bunch intensity and/or reducing the beam emittance. This leads to a larger beam-beam tuneshift parameter. Operations during 2006 have shown that the beam-beam interaction is already dominating the luminosity lifetime. To overcome this limitation, a near-integer working point is under study. We will present recent results of these studies. (characters:774)
    
    
61. C. Montag, A low $\gamma_t$ injection lattice for polarized protons in RHIC C. Montag
    Polarized protons are injected into the Relativistic Heavy Ion Collider (RHIC) just above transition energy. When installation of a cold partial Siberian snake in the AGS required lowering the injection energy by $\Delta \gamma=0.56,$ the transition energy in RHIC had to be lowered accordingly to ensure proper longitudinal matching. This paper presents lattice modifications implemented to lower the transition energy by $\Delta \gamma_t=0.8.$ (characters:446)
    
    
62. C. Montag, Touschek lifetime estimates for the NSLS-II C. Montag, J. Bengtsson, B. Nash
    The beam lifetime for medium energy synchrotron radiation sources is typically limited by the Touschek effect. While it is straightforward to estimate analytically, a realistic approach requires the momentum acceptance to be determined from tracking; due to the nonlinear dynamics. Especially, to include the effect from small vertical apertures from insertion devices. We outline how this can be done in a self-consistent manner, by constructing a realistic model. In particular, by including the alignment and magnetic field errors, and related corrected schemes to e.g. obtain the actual vertical beam size. (characters:611)
    
    
63. C. Montag, RHIC Polarized Proton Performance in Run-7 C. Montag, L. Ahrens, M. Bai, D. Barton, J. Beebe-Wang, M. Blaskiewicz, J.M Brennan, K.A. Brown, D. Bruno, G. Bunce, R. Calaga, P. Cameron, R. Connolly, T. D'Ottavio, A. Drees, A.V. Fedotov, W. Fischer, G. Ganetis, C. Gardner, J. Glenn, H. Hahn, T. Hayes, H.-C. Hseuh, H. Huang, P. Ingrassia, D.A. Kayran, J. Kewisch, R.C. Lee, V.N. Litvinenko, A.U. Luccio, Y. Luo, W.W. MacKay, Y. Makdisi, N. Malitsky, G. Marr, A. Marusic, R. Michnoff, J. Morris, B. Oerter, F. Pilat, P. Pile, T. Roser, T. Russo, T. Satogata, C. Schultheiss, K. Smith, S. Tepikian, D. Trbojevic, N. Tsoupas, J. Tuozzolo, A. Zaltsman, A. Zelenski, K. Zeno, S.Y. Zhang
    During Run-7, the Relativistic Heavy Ion Collider (RHIC) provided collisions of spin-polarized proton beams at two interaction regions. Helical spin rotators at these two interaction regions were used to control the spin orientation of both beams at the collision points. Physics data were taken with different orientations of the beam polarization. We present recent developments and improvements as well as the luminosity and polarization performance achieved during Run-7. (characters:477)
    
    
64. J. Niedziela, Wiki Experience at the BNL Collider-Accelerator Department J. Niedziela, W. Fu, P. Harvey, G. Marr, T. Satogata, V. Schoefer
    Centralization of information pertaining to accelerators can benefit accelerator operation and development. Further, retention and the changeable nature of information present challenges to accelerator operation, particularly in instances of turnover. MediaWiki is free, server-based software licensed under the GNU General Public License that uses PHP to render data stored in a MySQL database as interactive web documents, and is designed to produce collaborative documentation. The MediaWiki engine was implemented at BNL, and this paper describes the first year of use by the Operations, Controls, and RF groups at the Collider-Accelerator Department, including code modifications, common practices, and the use of the wiki as a training tool. (characters:752)
    
    
65. J. Niedziela, RHIC BBA Using Quadrupole and Bump Modulation J. Niedziela, P. Cameron, and T. Satogata
    Slowly sweeping a three bump across a quadrupole while modulating the quadrupole strength is an established method to perform beam-based alignment (BBA) of quadrupole and beam position monitor (BPM) pairs. We use a new method where both the quadrupole strength and bump height are modulated at different frequencies, and down-sampled turn-by-turn BPMs are used to find optimal centering. This paper discusses Matlab-based modeling for feasibility analysis and first results obtained during RHIC Run-7. (characters:502)
    
    
66. M. Okamura, Review of Laser Driven Sources for Multi-charged Ions M. Okamura, S. Kondrashev
    Laser beams have been widely used in the accelerator field for various applications. Here, we focus on ion beam production usage as an ion source. The laser ion source (LIS) already has about thirty years history and was developed for providing pulsed beam to synchrotrons. Since 2000 we have concentrated on the use of the high brightness of induced laser plasma to provide intense highly charged ions efficiently. To take advantage of the intrinsic density of the plasma, Direct Plasma Injection Scheme (DPIS) has been developed. The induced laser plasma has initial expanding velocity and can be delivered directly to the RFQ. The presentation will discuss general features of the laser ion sources and advantages of the DPIS. (characters:730)
    
    
67. S. Peggs, A Survey of Hadron Therapy Accelerators S. Peggs, J. Flanz, T. Satogata
    The number and variety of accelerator facilities for the irradiation of cancerous tumors by hadrons (mainly protons and carbon ions), and the number of patients treated each year, continue to grow approximately exponentially with time. This paper surveys the current state of hadron therapy accelerator science and technology. It also indicates, at the summary level, the clinical advantages - and disadvantages - of each technology branch. (characters:442)
    
    
68. F. Pilat, Increasing Time in Collision at RHIC F. Pilat, P. Ingrassia, J. Jamilkowski, G. Marr
    RHIC machine availability, defined as time running physics divided by calendar time, has increased to ~50% over the first 4 years of operation, and has not improved further during years 5 and 6 of operations. Though this figure is typical for a high-energy collider, our goal is to achieve an availability of 60% in two years, parallel to the goal of increased luminosity in both ion-ion and polarized proton collision modes. Following an analysis of the main impacts on time at store in RHIC, several changes have been made for Run-7, ranging from systems upgrades to improvement of operational procedures and maintenance management. We will report the results of these changes by comparing Run-7 run data to the previous operational history. A particular emphasis has been put on the development of sequences for the automation of operations, and on the development of web and database tools for online machine reliability analysis. We will discuss design, operational experience and results of our new control room automation and analysis software. (characters:1052)
    
    
69. F. Pilat, Dynamic Aperture Measurements at RHIC F. Pilat, M. Bai, V. Ptitsyn
    An experimental method of measuring dynamic aperture by increasing transverse emittance with continuous tune meter kicks has been developed and tested at RHIC. The RHIC ionization profile monitor capability of bunch-by-bunch measurement allows us to effectively use different bunches for measurements in different machine configurations. We present dynamic aperture measurements from a series of dedicated beam experiments at collision energy, where we determined the dependence of the dynamic aperture on optics, working points, momentum deviation, and different strengths of non-linear interaction region correctors. We also plan to explore feasibility of an alternative way to measure the dynamic aperture with beam excitation from an AC dipole and observation of BPM spectra during Run-7. This technique has the potential of providing a much faster way to determine the dynamic aperture at collision energy where the strength of the tune meter kicker is limited to a fraction of the beam distribution, and open the possibility of routine operational DA measurements. (characters:1072)
    
    
70. F. Pilat, Increasing Efficiency of Maintenance at RHIC F. Pilat, P. Sampson
    Increasing the efficiency of system maintenance is an important component in the optimization of operations of RHIC and its injectors undertaken at BNL, towards the goal of improving overall machine availability. Maintenance and accelerator support are now integral part of operations. A central component of the integration is the process of submitting, approving, scheduling and executing maintenance jobs. Work planning, access and maintenance procedures have been examined and revised. A system for logging maintenance activities that interfaces electronic logs and database was implemented. This paper outlines the tools, methods, documentation and results of the optimization measures described above, including a discussion of their effectiveness, as measured by the job completion statistics during the summer shut-down and the operational history of maintenance days during the run periods. (characters:900)
    
    
71. E. Pozdeyev, Electron Beam Alignment in the RHIC II Cooling Section E. Pozdeyev, I. Ben-Zvi, P. Cameron, A. Fedotov, D. Kayran, V. Litvinenko
    Numerical simulations of the BNL electron cooler indicate that the electron beam must be aligned to better than 5 microradians relative to the ion beam to keep the cooling efficiency high. This alignment accuracy has to be satisfied over the 100m-long cooling section, presenting a formidable task. To meet this requirement, diagnostics capable of accurately measuring trajectories of the overlapping ion and electron beams has to be developed. Additionally, the stray magnetic field at the cooling section has to be suppressed to the level of a few milligauss without disturbing the field of the undulator used to prevent electron-ion recombination. This paper presents the beam alignment requirements and provide details on the techniques we propose to meet those requirements. (characters:780)
    
    
72. E. Pozdeyev, Method to Increase Lifetime of Photocathodes in DC Guns E. Pozdeyev, J. Grames, M. Poelker
    DC photoguns are used to produce high-quality, high-intensity electron beams for accelerator driven applications. Ion bombardment is credited as the major cause of degradation of the photocathode efficiency. Additionally to ions produced in the accelerating cathode-anode gap, the electron beam can ionize the residual gas in the transport line. These ions are trapped transversely within the beam and can drift back to the accelerating gap and contribute to the bombardment rate of the cathode. This paper proposes a method to reduce the flow of ions produced in the beam transport line and drifting back to the cathode-anode gap by introducing a positive potential barrier that repels the trapped ions. The reduced ion bombardment rate and increased life time of photocathodes will reduce the downtime required to service photoinjectors and associated costs. (characters:861)
    
    
73. E. Pozdeyev, Diagnostics of BNL ERL E. Pozdeyev, I. Ben-Zvi, P. Cameron, D. Gassner, D. Kayran, V. Litvinenko, T. Srinivasan-Rao
    The ERL Prototype project is currently under development at the Brookhaven National Laboratory. The ERL is expected to demonstrate energy recovery of high-intensity beams with a current of up to a few hundred milliamps, while preserving the emittance of bunches with a charge of a few nanocoulombs produced by a high-current SRF gun. To successfully accomplish this task the machine will include beam diagnostics that will be used for accurate characterization of the three dimensional beam phase space at the injection and recirculation energies, transverse and longitudinal beam matching, orbit alignment, beam current measurement, and machine protection. This paper outlines requirements on the ERL diagnostics and describes its setup and modes of operation. (characters:762)
    
    
74. E. Pozdeyev, Collective Effects in the RHIC-II Electron Cooler E. Pozdeyev, I. Ben-Zvi, A. Fedotov, D. Kayran, V. Litvinenko, G. Wang
    Electron cooling at RHIC-II upgrade imposes strict requirements on the quality of the electron beam at the cooling section. Beam current dependent effects such as the space charge, wake fields, CSR in bending magnets, trapped ions, etc., will tend to spoil the beam quality and decrease the cooling efficiency. In this paper, we estimate the defocusing effect of the space charge at the cooling section and describe our plan to compensate the defocusing space charge force by focusing solenoids. We also estimate the energy and emittance growth cased by wake fields. Finally, we discuss ion trapping in the electron cooler and consider different techniques to minimize the effect of ion trapping. (characters:697)
    
    
75. D. Raparia, End-to-End Simulation for the EBIS Preinjector D. Raparia, J. Alessi, A. Kponou, A. Pikin, J. Ritter, U. Ratzinger, A. Schempp, R. Tiede
    The EBIS Project at Brookhaven National Laboratory is in the second year of a four-year project. It will replace the Tandem Van de Graaff accelerators with an Electron Beam Ion Source, an RFQ, and one IH Linac cavity, as the heavy ion preinjector for the Relativistic Heavy Ion Collider (RHIC), and for the NASA Space Radiation Laboratory (NSRL). The preinjector will provide all ions species, He to U, (Q/m ?0.16) at 2 MeV/amu at a repetition rate of 5 Hz, pulse length of 10-40 ?s, and intensities of ~2.0 mA. End-to-end simulations (from EBIS to the Booster injection) as well as error sensitivity studies will be presented and physics issues will be discussed. (characters:665)
    
    
76. T. Satogata, RHIC Challenges for Low Energy Operations T. Satogata, J.M. Brennan, A. Drees, A. Fedotov, T. Roser, N. Tsoupas
    There is significant interest in RHIC heavy ion collisions at c.m. energies of 5-50 GeV/u, motivated by a search for the QCD phase transition critical point. The low end of this energy range is far below the nominal RHIC injection c.m. energy of 19.6 GeV/u. There are several challenges that face RHIC operations in this regime, including longitudinal acceptance, magnet field quality, lattice control, and luminosity monitoring. We report on the status of work to address these challenges and include results from beam tests of low-energy RHIC operations with protons and gold. (characters:579)
    
    
77. T. Satogata, Orbit Response Matrix Analysis at RHIC T. Satogata, M. Bai, J. Niedziela, N. Malitsky
    Orbit response matrix (ORM) measurements are commonly used in many circular accelerators to measure and correct gradient errors, beam position monitor gain errors, dipole corrector gain errors, and local coupling. The Matlab version of LOCO has been used at RHIC to analyze coupled ORMs for injection and storage optics in both RHIC rings. We report on ORM analysis results for RHIC in these conditions, including improvements to machine optics and operation, and online modeling. (characters:481)
    
    
78. D. Trbojevic, Acceleration of Electrons with the racetrack Non-Scaling FFAG for e-RHIC D. Trbojevic, M. Blaskiewicz, V. Litvinenko, V. Ptitsyn, and T. Roser
    Acceleration of electrons up to 10 GeV for a future electron-ion collider eRHIC (Relativistic Heavy Ion Collider) could be performed with the energy recovery linac with multiple passes. An energy recovery scheme is required if a superconducting linac is used for acceleration. We report on an attempt to make a combination of a multi-pass linac with non-scaling FFAG (Fixed Field Alternating Gradient) arcs. Two non-scaling FFAG arcs would allow electrons to pass through the same structure with different energies. The beam will be accelerated by the superconducting linac at the top of the sine function, and returned to the front of the linac by the non-scaling FFAG. This process is repeated until the total energy of 10 GeV is reached. After collisions the beam is brought back by the non-scaling FFAG and decelerated before being dumped. (characters:844)
    
    
79. D. Trbojevic, Muon Acceleration with the racetrack FFAG D. Trbojevic, E. Keil, and A. Sessler
    There are several technical challenges for muon acceleration for a future muon collider or neutrino factory. We report a design of a racetrack non-scaling FFAG (Fixed Field Alternating Gradient) accelerator to allow fast muon acceleration in small number of turns. The racetrack design is made of four arcs: two arcs at opposite sides have smaller radii are made of closely packed combined function magnets, while two additional arcs with very large radii are used for muon extraction, injection, and RF accelerating cavities. The ends of the large-radii arcs are geometrically matched at the connections to the arcs with smaller radii. The dispersion and both horizontal and vertical amplitude functions are matched at the central energy. (characters:740)
    
    
80. D. Trbojevic, Heavy Ion Acceleration in RIA with the Non-Scaling FFAG D. Trbojevic, J. Alessi, E. Beebe, A. Pikin, E. Keil, T. Roser, S. Ruggiero, and A. Sessler
    To reduce the linac expense in the Rare Ion Accelerator (RIA) we explore the possibility of using two non-scaling Fixed Field Alternating Gradient (FFAG) reducing the number of RF cavities. The ~10 MeV injector is assumed to be a combination of ECR (Electron Cyclotron Resonance) and EBIS (Electron Beam Ion Trap) ion sources, RFQ (Radio Frequency Quadrupole) and a short linac. To be able to use advantages of multi-pass small aperture non-scaling FFAG the EBIS ion source would have to be able to deliver microseconds long heavy ion beam bunches, being fed in milliseconds from an ECR. The heavy ion maximum kinetic energy is assumed to be 400 MeV/u with a total of 400 kW power in the case of uranium ions. This energy is achieved by heavy ion acceleration from 10 MeV/u to 67 MeV/u with the first non-scaling FFAG with ~500 turns, while after stripping the second non-scaling FFAG is designed to accelerate ions from 67-400 MeV/u. (characters:935)
    
    
81. D. Trbojevic, Superconducting Non-Scaling FFAG Gantry for Carbon/Proton Cancer Therapy D. Trbojevic, R. Gupta, B. Parker, E. Keil
    We report on improvements in a non-scaling Fixed Field Alternating Gradient (FFAG) gantry design. As we previously reported, a major challenge of carbon/proton cancer therapy facilities is isocentric gantry design. The weight of the isocentric gantry in the latest Heidelberg carbon/proton facility is 630 tons. In this report, we detail improvements to the previous non-scaling gantry design. We estimate that this non-scaling FFAG gantry would be almost 100 times lighter than traditional heavy ion gantries. Very strong focusing with small dispersion permits passage of different energies of carbon beams through the gantry's fixed magnetic field. (characters:652)
    
    
82. N. Tsoupas, Design of a Thin Quadrupole to be used in the AGS Synchrotron N. Tsoupas, L. Ahrens, R. Alforque, M. Bai, K. Brown, E. Courant, W. J. Glenn, H. Huang, A. Jain, W. W. Mackay, I. Marneris, T. Roser, S. Tepikian
    The AGS synchrotron employs two partial helical snakes to preserve the polarization of the proton beam during acceleration in the AGS. The effect of the helical snakes on the beam optics is significant at injection energy, with the effect greatly diminishing early in the acceleration cycle. In order to compensate for the effect of the snakes on the beam optics, we have introduced eight "compensation" quadrupoles in straight sections of the AGS at the proximity of the partial snakes. At injection the strength of these eight quads is set at a high value but ramped down to zero when the effect of the snakes diminishes. Four of the compensation quadrupoles had to be placed in very short straight sections therefore had to be "thin" with a length of ~30 cm. The "thin" quadrupoles were laminated and designed to minimize the strength of the dodecoupole harmonic. The thickness of the lamination was also calculated to keep the ohmic losses generated by the eddy currents in the laminations below an acceptable limit. Comparison of the measured and calculated harmonics will be presented and the ohmic losses due to the eddy currents, as a function of time during rumping will be discussed. (characters:1194)
    
    
83. N. Tsoupas, Design of the Beam Transfer Line for the NSLS II N. Tsoupas, T. Shaftan, C. Stelmach
    The proposed NSLS II light source to be built at Brookhaven National Laboratory utilizes two synchrotron accelerator rings, the Booster and the Storage-ring which share the same tunnel, but with different horizontal planes. The "Booster" accelerates the electron beam to an energy of 3.0 GeV and the beam is quickly extracted to the "Booster to Storage Ring" (BtS) transport line. The BtS line transports the beam and injects it into the "Storage" ring . In order to facilitate the design of the BtS transfer line, the line has been partitioned in three sections which can be considered as independent. The first section ("first horizontal achromat" ) forms an acromatic line and is matched to the beam parameters at the extraction point of the Booster and is also matched to the beam parameters of the starting point of the second section ("Vertical dog-leg"). The "Vertical dog-leg" section, transports the beam from the plane of the Booster ring down to the plane of the Storage ring. This section is designed to be achromatic in both planes, and also defines the twiss parameters of the BtS line at the beginning and the end points of the "Vertical dog-leg" section. The third section ("second horizontal achromat") is matched to the beam parameters at the exit of the "Vertical dog-leg" section, and also to those at the injection point of the storage ring. The procedure for the design of the BtS line and other details about the optics and the magnetic elements of the line will be presented in the paper. (characters:1513)
    
    
84. N. Tsoupas, Uniform Beam Distributions at the Target of the NSRL Beam Transfer Line N. Tsoupas, S. Bellavia, R. Bonati, K. Brown, I-Hung Chiang, C.J. Gardner, D. Gassner, S. Jao, I. Marneris, D. Phillips, P. Pile, R. Prigl, A. Rusek, L. Snydstrup, K. Zeno
    Uniform Beam Distributions at the Target of the NSRL Beam Transfer Line Uniform irradiation of biological or material samples with charged particle beams is desired by experimentalist because it reduces radiation_dose_errors which are introduced by a non_uniform irradiation of the samples. In this paper we present results of uniform beams produced in the NASA SPACE RADIATION LABORATORY (NSRL) at the Brookhaven National Laboratory(BNL) by a method which was conceived theoretically and tested experimentally at BNL. This method of producing uniform beams in the transverse beam direction, is based on purely magnetic focusing of the beam and requires no collimation of the beam or any other type of beam interaction with materials. The method is favorably compared with alternative methods of producing uniform beam distributions normal to the beam direction and can be applied to the whole energy spectrum of the charged particle beams that are delivered by the Booster synchrotron at BNL. (characters:994)
    
    
85. G. Wang, Coherent Instability Of RHIC Ion Beam Due to Electon Cooling G. Wang, M. Blaskiewicz
    A circulating ion beam in the presence of electron cooling can experience varies instabilities if the electron beam intensity is above a certain threshold. Firstly the electric field generated by the electron beam can introduce two stream instabilities of varies modes; this has already been observed in the Fermilab Recycler ring. Secondly, longitudinal cooling of the momentum spread will reduce the Landau damping efficiency and thus may make the overcooled ion beam unstable. The thresholds and growth rates of varies two stream instability modes are discussed for the existing RHIC electron cooler design. Both simulation and theoretical results are shown for the thresholds of the instabilities caused by overcooling. (characters:724)
    
    
86. J. Wei, China Spallation Neutron Source Project Status J. Wei
    The China Spallation Neutron Source (CSNS) project consists of four major systems: an accelerator complex consisting of an H- linear accelerator and a rapid cycling synchrotron accelerating the beam to 1.6 GeV at 25 Hz repetition rate; a target station of solid tungsten metal; five spectrometers (high intensity powder diffractometer, high resolution powder diffractometer, reflectometer, small angle diffractometer, and direct- geometry inelastic spectrometer), and conventional facilities. The primary challenge is to build a robust and reliable user's facility with upgrade potential at a fraction of "world standard" cost. During the past years, major prototyping R&D were started on key technical components including ion source body, RFQ, DTL, ring magnets, power supplies, RF cavity, ceramic vacuum chamber, target core, neutron guide, and detectors. This paper presents the present project status. (characters:910)
    
    
87. J. Wei, Analytical Formalism for 1D Crystalline Beam Stability in an AG Focusing Ring J. Wei, H. Okamoto, S. Ochi, and A.M. Sessler
    Analytical study of crystalline beam stability in an alternating gradient (AG) focusing storage ring was previously limited to the smooth approximation. In a typical ring, analytical results obtained under such approximation largely agrees with the results obtained with the molecular dynamics (MD) simulation method. However, as we explore ring lattices appropriate for beam crystallization at high energies (Lorentz factor gamma much higher than the betatron tunes), such approximation fails. Here, we present a newly developed formalism to exactly predict the stability of a 1-dimensional crystalline beam in an AG focusing ring lattice. (characters:641)
    
    
88. W. T. Weng, Operations of the AGS as a High Power Proton and Heavy Ion Driver W. T. Weng and T. Roser
    The International Scoping Study for future Neutrino Factory specified the preferred parameters of a potential proton driver as having beam power 2 to 4 MW, beam energy 5 to 10 GeV, bunch length less than 3 nsec, repetition rate about 50 Hz(1). In this report, we try to modify the AGS operation to be as close to the required performance as possible. One novel feature of achieving 3 nsec bunch length is to extract the beam around the AGS transition energy of about 8.5 GeV. By doing this, the bunch length is automatically reduced to a few nsec without high power rf bunch rotation system which is typically required by other design. Operate the AGS around 8.5 GeV can also provide good Pion production efficiency and increase the rep rate to 5 to 10 Hz. We also consider the possibility of accelerating U(28+) in the AGS to about 2.0 GeV/n for rare isotope production for nuclear research. The equivalent beam power delivered would be about 100 KW due to the higher rep rate adopted. This paper will describe the machine physics issues of both schemes and the associated modifications needed of the power supply, rf, and injection system. (characters:1142)
    
    
89. Q. Wu, Thermal Emittance Measurement Design for Diamond Secondary Emission Q. Wu, I. Ben-Zvi, A. Burrill, X. Chang, D. Kayran, T. Rao, J. Smedley
    Thermal emittance is a very important character to cathodes. Lower thermal emittance cathode has better performance in emittance limit and injection down in the beam line. Diamond amplified photocathode, being a negative electron affinity (NEA) cathode, promises to deliver a very small thermal emittance. A carefully designed method of measuring the emittance of diamond secondary emission is presented for the first time. Comparison of possible schemes is carried out by simulation, and the most accessible and accurate method and values are chosen. System error can be controlled within a very small range, and is carefully evaluated. Aberration and limitations of all equipments are taken into account. (characters:707)
    
    
90. W. Zhang, Large Scale Distributed Parameter Model of Main Magnet System and Frequency Decomposition Analysis W. Zhang, I. Marneris, J. Sandberg
    Large accelerator main magnet system consists of hundreds, even thousands, of dipole magnets. They are linked together under selected configurations to provide highly uniform dipole fields when powered. Distributed capacitance, Insulation resistance, coil resistance, magnet inductance, and coupling inductance of upper and lower pancakes make each magnet a complex network. When all dipole magnets are chained together in a circle, it becomes a coupled pair of very high order complex ladder networks. In this study, a network of more than thousand inductive, capacitive or resistive elements are used to model an actual system. The circuit is a large scale network. Its equivalent polynomial form is of several hundred degrees. To analyze this high order circuit and to simulate the response of any or all components, even the computer is pushed to its limit. Therefore, frequency decomposition approach is used to effectively simulate and analyze the magnet configuration and power supply topologies. (characters:1005)
    
    
91. W. Zhang, Analysis and Simulation of the Main Magnet Transmission Line Effect W. Zhang, I. Marneris, J. Sandberg
    The main magnet chain forms a pair of transmission lines. Pulse reflection caused voltage and current differentiation through out the magnet chain can have adverse effect on main magnet field quality. This effect is associated with magnet system configuration, coupling efficiency, and parasitic parameters. A better understanding of this phenomenon will help us in new design and existing system upgrade. In this paper, we exam the transmission line effect due to different input functions as well as configuration, coupling, and other parameters. Although the transmission line effect is a concern, oscillations due to other system components might deserve more attention. (characters:675)
    
    
92. A. Zelenski, Towards 100% polarization in the RHIC Optically Pumped Polarized H- Ion Source A. Zelenski, J. Alessi, S. Kokhanovskiy, A. Kponou, V. Zubets
    The main depolarization factors in the multi-step spin-transfer polarization technique and basic limitations on maximum polarization in the different Optically-Pumped Polarized H- Ion Source (OPPIS) schemes will be discussed. Detailed studies of polarization losses in the RHIC OPPIS and source parameter optimization resulted in an OPPIS beam polarization increase to 86±1.5%. This contributed to AGS and RHIC polarization increase to 65-70%. (characters:444)
    
    
93. S.Y. Zhang, Proton beam emittance growth at RHIC S.Y. Zhang and V. Ptitsyn
    The beam emittance growth in RHIC polarized proton runs has a dependence on the dynamic pressure rise, which is caused by the electron cloud and peaked at the end of the beam injection and the early energy acceleration. This emittance growth is usually presented without beam instability, and it is slower than the ones above the instability threshold. The effect on the machine luminosity, nevertheless, is significant, and it is currently a limiting factor in machine performance. The electron cloud is substantially reduced at the store, the emittance growth there has no dependence on the bunch spacing and instead it has a clear dependence on the beam-beam parameter. The results of the machine operation and beam studies will be reported. (characters:745)
    
    
94. S. Zhang, Experimental background in polarized proton runs at RHIC S. Zhang and D. Trbojevic
    There are three main sources of the experimental background at RHIC. The beam-gas induced background is associated with the vacuum pressure, the beam-chamber-interaction induced background can be improved by collimations, and the beam-beam induced background is somewhat inherent, and probably harmless for the experimental data taking. The zero degree calorimeter (ZDC) is an essential luminosity detector for heavy ion operations in RHIC. It is shown that, however, the ratio of ZDC singles (background) and coincident rate is also useful in proton runs for background evaluations. In this article, the experimental background problem in RHIC polarized proton runs is reported. (characters:680)