FY 2013 AGS Polarized Proton Run Plan

January 7, 2013

Haixin Huang




·        RHIC PP Run 13

o   Jan. 22:  Polarized proton beam injected into Booster->AGS

o   Feb. 4(subject to change):  Switch to Siemans

o   Feb. 14:  Injection into Blue


Baseline goal for extraction: 65% polarization at >1.5e11 protons.


Job List

·        Take ORM data with snake off and on. Verify magnet survey impact on beta beat (Vincent)

·        Monitor the orbit instability issue and scan corrector on/off sequentially through the ring (Vincent)

·        Measure emittance with several flattops so we can get emittance with RF off at various energies.(Haixin)

·        Beta function measurement at C5 and E15 IPM (Haixin)

·        Commissioning the RHIC type IPM at D5(Roger)

·        Setup RF h=2 and h=1 in the Booster with different Booster users. Compare the longitudinal emittance in the AGS. (KevinS, Keith)

·        Check polarization at AGS flattop with different Booster RF setup.

·        Model comparison data taking. (Francois, Yann)

·        Injection match study (Vincent)

·        AGS BBQ tune meter preliminary study (Kevin Mernick)

·        Horizontal tune jump quads setup. For Westinghouse, need to develop a new file. For Siemens, start with same files which gave the best polarization from last run (Rocco, Haixin)

·        Setup downramp without jump quads. Take polarization measurement with both up and down ramp. (Keith, Kin, Haixin)

·        Measure polarization with low intensity but two very different emittances (by mis-steering at injection). The key is to have low intensity so that no beam loss on the ramp. (Haixin)

·        On a different AGS user, run stronger cold snake (282A). Measure polarization profiles with jump quads on and off in this case (Keith, Haixin)

·        Scraping beam off at flattop vertically by F5. Check polarization and emittance (Anatoli)

·        Polarization ramp measurement with Siemens at Ggamma=45.5 (JQ on). 

·        Polarization profile (both horizontal and vertical) measurements at Ggamma=45.5 (JQ on/off). 

·        Polarization ramp measurement with Westinghouse and jump quads on/off, if we have time to set up jump quads beneficially. 

·        Polarization ramp measurement with flattop at Ggamma=45.5 and 48.5 (JQ off). 

·        Polarization measurement with radial jump near Ggamma=45.3 (JQ on/off). 

·        Test extraction-on-the-fly scheme with beam to W dump. 

Startup Schedule

·        Jan. 22: Start pp setup in the AGS user1 with Westinghouse. Set up pp in AGS user4 for Siemens. Run for the rest of three weeks with two shifts.

·        Feb. 3 or later: AGS pp setup with Siemens.



Beam Plans

·        Machine parameters:

o   ν_x=8.70, ν_y~8.95 at injection(archive from last run).

o   RF parameter: Start with Booster H=1 on Booster user 1 and move on to Booster user4 with h=2. AGS H=8 on user 1 (Westinghouse) and user4 (Siemens).

o   At injection, transverse emittance 10π (95% normalized); longitudinal emittance <0.8eV-s. >

o   Warm snake current=2670A.(6.7% at injection, 5.9% at extraction).

o   Cold snake helix current=238A and solenoid current=152A. The solenoid field is allowed to change for best coupling correction in addition to the skew quads. (13% at injection, 10% at extraction).

o   AGS rep rate=5 sec. for Westinghouse and 4sec. for Siemens (eventully move to 3.3 sec.).

o   The injection and extraction energies: = 4.5 and = 45.5, respectively.

Setup with Both Snakes Off

·        Establish beam in the Booster and then the AGS with both snakes off. [1-2 shifts]

·        Setup RF to establish beam at flattop. [1-2 shifts]

·        REV-TICK and Tunemeter setup. The tunemeter is critical to check tunes when snakes are on. As soon as it is done, we should move forward to snake on machine. [0-1 shift]

·        Move to HIGH VERTICAL TUNE at extraction, measure beta beat:  sin/cos response + midnight ORM

·        CNI polarimeter setup. The setup can start as soon as beam survives at extraction energy. It may take more than two shifts allocated here, but it can be stopped and continue after snake on. Prior to this work, the orbits (both horizontal and vertical) at top energy in C15 section should be set as flat (both in time and angle) as possible. Since the polarimeter setup involves different crew, it can be done in parallel with other activities. [1-2 shifts]


Setup with Both Snakes On

·        Establish beam in the AGS (injection at =4.5, extraction at = 45.5 with snake on. Start with on-demand mode and intensity of a few 10^10. Turn on cold snake (helical 238A, solenoid 152A,trim1 0A, trim2 7A) and E20 warm snake (2670A). Turn on correction quads and bumps for both snakes. While tuning the injection beam survival(first with rf off, then rf on), the beam dump bump (J10) should be on at injection porch. After reaching a few times 10^10 beam survives, remove the dump bump and tune for beam survival along the ramp. It may be efficient to load archives from last run and get beam circulating first with that setting. [3-5 shifts]

·        Commissioning instrumentation if not finished before: AGS tune-meter; IPM. [0-1 shift]

·        CNI polarimeter commissioning if not finished yet before. Since the polarimeter setup involves different crew, it can be done in parallel with other activities. [2 shifts].

·        Ramp development:

o   Tune the AGS injection to maximize beam survive at injection. Minimize emittances at AGS extraction (judged by IPM with rf off).

o   Correct both horizontal and vertical orbits with iterations.

o   Tune the 8th and 9th harmonics along the ramp.

o   Start with vertical tune around 8.8 along the ramp.

o   Raise vertical tunes along the ramp while tuning the orbit. The vertical tune should be chosen to avoid the higher order snake resonances, especially at 36+ν. The proposed vertical tune values are: 0+ν (~8.96 or higher), 12+ν (~8.97) , 36-ν(8.98) and 36+ν(8.985).

o   Measure polarization at extraction.
[4-6 shifts]


·        Measure polarization at extraction as function of B field. The field scan should cover = 44.5 to 46. [4 shifts]

·        Increase intensity from source gradually to the desired intensity. Measure polarization as intensity goes up. [2 shift]

·        Measure polarization at extraction as function of various quantities. There are several potential causes for polarization loss and they need to be scanned. The purpose of these scans are to find the optimum working point, so there is no need to make wide range scan. [4 shifts]

o   Vertical tune not high enough before 0+ν.

o   Vertical tune not high enough at 0+ν (high order snake resonance).

o   Vertical tune not high enough at 36+ν (high order snake resonance).


·        Harmonics corrections in Booster for both =3 and 4, sine and cosine. This will be done at injection energy (step size of 4A). [1-2 shifts]

·        Expect to reach 65% polarization (with 80% as input) and 1.5*10^11 intensity. When this goal is reached, the remaining time will be divided into four parts: Emittance measurement; Further tune jump quads test; Up and down ramp polarization measurements; CNI polarimeter test.


Tune Jump Quads

·  Measure betatron tune along the ramp with each of the two jump quads on and off. Compare to last run for any difference (after survey). Setup the tune jump quads strength based on the tune measurements. Setup the precise tune jump timing based on the tune measurements. [4 shifts]

·  Setup the orbits centered at the two tune jump quads. Measure beam emittances to see improvement. It may requires several iterations. Commission ‘smoothing’ mode of orbit feedback.[1 shifts]

·  Repeated polarization measurements at =45.5 with jump quads on and off at beam center. [2 shifts]

·  Repeated polarization measurements at =45.5 with jump quads timing shifted ( timing scan). [4 shifts]

·  After seen the jump quads effect, take horizontal polarization profiles at =45.5 with jump quads on and off. A stronger cold snake on different AGS user may be needed for this test.[2-4 shifts]

·  The procedure needs to be repeated for Siemens after done with Westinghouse.



AGS pp Operation System Experts

Booster scraping: Keith
BtA lattice: Keith, Nick, Kevin
AGS/Booster optics control application: Kip, Kevin
AGS injection tuning: Keith
AGS RF: Keith, KevinS
AGS tune-meter: Dave Maffie
AGS orbit control and display: Vincent, Keith, Shawn
AGS Jump Quad System: Rocco, Vincent, Wenge
AGS Ggamma_meter: Rocco
Data spreadsheet: Seth
AGS snake operation: Haixin
Snake bumps and corrections: Nick
AGS E880 polarimeter: Haixin
AGS CNI polarimeter: Kin,Andrei, Haixin
AGS extraction: Vincent, Greg, Nick
AGS lattice matching: Vincent, Francois, Nick