Injector PP Setup Plan and Status

1
Injector PP Setup Plan and Status
Haixin Huang
November 18, 2008
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Sources of Polarization Loss

• Category the known polarization loss into three
  parts
• Overall loss due to the horizontal resonances
  with real ramp rate. (related to horizontal
  emit.)
• Near injection due to vertical tune outside spin
  tune gap. (related to vertical tune and emit. )
• Loss due to snake resonances, mostly near 36?y .
  (related to vertical emit.)
• There may still be some additional polarization
  loss due to not perfect vertical tune path or too
  large a tune spread.

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Strategy to Overcome Polarization Loss

• There are significant emittance growth in the
  injector chain
• Emittance growth in the LEBT/MEBT of linac.
• Multiple scattering at stripping foil at LtB.
• BtA optics mismatch.
• The plan is to solve these emittance growth
  problem one by one
• LEBT/MEBT upgrade (currently under testing)
• Change the LtB foil manipulate beta function at
  the foil to reduce the emittance growth (Will
  test it after Jan. 12)
• BtA study to better understand the BtA line and
  AGS optical model. (data analysis underway)
• Setup AGS injection with vertical tune in the
  spin tune gap (gt8.95). (Working on the modeling)
• Installation of two tune jump quads to mitigate
  the polarization loss due to horizontal
  resonances.
• Change RF setup from h12 to h6 to reduce space
  charge effect (more important due to expected
  smaller emittances).

4
LEBT/MEBT Upgrade Status
(from Deepak)

• OPPIS source was reconfigured and tested. OPPIS
  source is fully operational
• High intensity source being reassembled and
  tested
• LEBT (35 KeV) line for both sources are built and
  under vacuum
• Beam from OPPIS was transport to RFQ and
  transmission (from OPPIS to the end of RFQ) is as
  expected (gt90 for OPPIS solenoid off, 65 for
  OPPIS solenoid on)
• We are putting one more EINZEL lens (contingency
  plan) to provide one more degree of freedom to
  match into the RFQ.
• MEBT (75 KeV) line was vacuum tested, and found
  RFQ was 2 mm lower than Tank-1
• Now, we are realigning MEBT.
• We plan to put beam (both, polarized and high
  intensity) in Tank -1 in the 1st week of Dec.
• On schedule to be ready by early Jan.

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Horizontal Tune Jump Status

• Ceramic chambers have been ordered.
• Cables pulling is going on (which is a must
  before run starts).
• Control hardware purchase has started.
• P/S will be modified from existing ones. Some
  parts have been ordered.
• Magnet coil and assembly have started bidding
  process.
• Expect to get the magnets around end of Jan. They
  will be tested by magnet division.
• Current schedule is that the magnets can be
  installed sometime in early March during
  maintenance day. We would like to have 3-4 weeks
  time to commission them.

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AGS Setup

• Start Booster on Jan. 12. With LEBT/MEBT upgrade,
  it is worthwhile to check the emittances at the
  BtA. The new LtB foil test and the beta function
  manipulation at LtB foil will be the major work.
• Start the three weeks of setup time before blue
  ready for beam Jan. 19
• CSNK 2.1T WSNK 1.53T as usual.
• AGS RF setup same as last year (h12), we may
  switch to h6 when RHIC is up running (due to
  limited resources from RF group for RHIC LLRF
  upgrade).
• Apply the knowledge gained from BtA studies to
  get a matched optics.
• Injection optics injection with dwell field but
  high vertical tune (gt8.95). It is worth of trying
  to see if it is feasible.
• Horizontal tune will set close to 8.70 throughout
  the ramp to make tune jump setup easier.
• Horizontal tune jump wont be ready on day one.
  The gain on polarization is hoped from smaller
  emittance out of linac and better matching at AGS
  injection.

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Backup Slides
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Run6 Polarization vs. Intensity
model
fitting
Experimental data are normalized to the 200MeV
polarization and then assuming 82 AGS input.
Model prediction taken into account AGS input as
82, spin mismatch at injection and C15. The
emittance dependence on intensity was taken from
fitting of measurements between 3/21/06-6/12/06
?x9.212.30I ?y 7.904.13I, where I is
intensity in unit of 1011.
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Spin Tune and Qy vs Gg
(Courtesy of Nick)