Vincent Schoefer
Overview
·
RHIC Spin Run 11
o TBD: Polarized proton beam injected into
Booster->AGS
o TBD: AtR available
o 1/1: Injection into Blue
Baseline goal for extraction: 65% polarization at 1.5e11 protons.
Commissioning
goals
·
Verify magnet survey impact on 6theta beta beat (Vincent)
·
Make horizontal tune jump quads operational (Woody)
·
Commission orbit harmonic feedback system and make operational
(Leif)
·
Tune jump quad application
·
Test new CNI boards and motion control (Anatoli,
Haixin)
·
AGS BBQ tune meter preliminary study (Kevin Mernick)
·
Matching to RHIC 9 MHz
·
Simultaneous
commissioning of EBIS Au and U beams in Booster->AGS->AtR
Startup Schedule
·
TBD: AGS walkthrough and SWEEP (start of
controlled access)
·
TBD:
Access controls, power supply testing and hi-pot
·
TBD:
(Friday) MCR checkout of BtA/AGS, verify AGS user 4
setup for p^
·
TBD:
(Monday) AGS heat run, Linac on
·
TBD: Install
CNI boards, close up, reload p^ user functions (over heat run functions)
·
TBD:
Injection into Booster
Beam Plans
·
Machine parameters:
o ν_x=8.70, ν_y~8.95 at injection(archive
from last run).
o At injection,
transverse emittance 10π (95% normalized);
longitudinal emittance <0.8eV-s. >
o Warm snake
current=2670A.(8.5% at injection, 5.9% at extraction).
o Cold snake helix
current=238A and solenoid current=152A. (15.8% at injection, 10% at
extraction).
o AGS rep rate=4
sec.
o The injection and
extraction energies: Gγ = 4.5 and Gγ = 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 Gγ=4.5,
extraction at Gγ = 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 Gγ = 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 9th harmonics in
the early part of the ramp.
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 can be done at flattop energy with large current variation (step
size of 10A). [1-2 shifts]
·
Expect to reach 50-65% polarization (with 80% as input)
and 1-1.5*10^11 intensity. When this goal is reached, the remaining time will
be divided into three parts: 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. 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 Gγ=45.5 with jump quads on and off at beam center. [2 shifts]
· If not seen polarization gain with quads
on, take repeated polarization measurements with jump quads on and off at beam
center at Gγ=45.5 with tunemeter
kick on. [2 shifts]
· Repeated polarization measurements at Gγ=45.5 with jump quads timing shifted ( timing scan).
[4
shifts]
· After seen the jump quads effect, take horizontal
polarization profiles at Gγ=45.5 with jump quadson and off. [2 shifts]
EBIS
Work in the Booster with He and Ne likely to occupy EBIS until Thanksgiving
(11/24). Thereafter, work in the Booster
with Au (and maybe U) will commence (PPM with p^ from Linac).
Time-sharing of AGS thereafter contingent on polarization
progress.
AGS pp Operation System Experts
Booster
scraping: Keith
BtA lattice: Keith, Nick, Kevin
AGS/Booster
optics control application: Kip, Kevin
AGS
injection tuning: Keith, Leif, Woody
AGS
RF:
Keith, KevinS
AGS
tune-meter: Leif
AGS
IPM:
Kevin
AGS
orbit control and display: Leif, Woody
Data
spreadsheet: Seth
AGS
snake operation: Haixin, Leif
Snake
bumps and corrections: Nick, Leif, Alfredo
AGS
E880 polarimeter: Haixin
AGS
CNI polarimeter: Kin, Haixin
AGS
extraction: Vincent, Greg, Nick
AGS
lattice matching: Alfredo, Nick