FY 2004 AGS Polarized Proton Run Plan

updated March 17, 2004

Haixin Huang

Environment: The setup of the AGS for polarized running takes place behind RHIC stores, with Au in the two RHIC rings. RHIC activities required for the present run generally take priority but should not affect our setup.

 

General Objectives:

 

a) Establish an injector setup providing protons with polarization above 50% (or “as high as possible”) and >10^11/bunch at a Gγ = 46.5 energy.

 

b) Understand the sensitivity of this setup to the usual parameters – emittance, tunes(t), chromaticity(t), snake strength(t), beam intensity, etc.

 

c) Commission the new Helical warm snake. Expect work on orbit corrections at injection and  along the ramp.

 

d) Commission the new upgraded AGS CNI polarimeter. To make real progress in understanding polarization losses in AGS, the new CNI polarimeter is essential. Therefore commissioning this polarimeter will be a major piece of the plan.

 

The time estimated at end of each task should time a factor two for scenario running behind RHIC.  So the plan is to deliver 50% polarization to RHIC in about three weeks.

 

Plans

 

Pre-snake stage: The likely scenario would be that helical snake not ready on day one of AGS pp operation. We would like to use this time to work on general AGS main magnet function setup, Booster harmonic correction (with e880 polarimeter).

  1. Establish beam in the Booster then AGS (full ramp). The injection energy will be lowered from Ggamma=4.7 to 4.5. Correct orbit for the bare machine (no helical snake). (4-5 shfits)
  2. E880 polarimeter setup ( 2 shifts).
  3. Harmonics corrections in Booster (4-5 shifts).
  4. CNI polarimeter commissioning (4-5 shifts).

 

Snake ready stage:

  1. With full energy ramp, turn on H snake at nominal field and correct orbit locally around the snake in E20.  The correction is most significant around injection. (1-2 shifts)
  2. CNI polarimeter commissioning (4-5 shifts)
  3. Briefly measure polarization at Ggmma=7.5 with E880 polarimeter. ( < 1shift).
  4. Timing the AC dipole pulses at 0+nu, 12+nu, 36-nu and 36+nu. AC dipole timing and amplitude scan at Ggamma=46.5.  (~10 shifts)

 

Expect to reach 50% polarization (with 75% as input) and 10^11 intensity (this has never been done before). If this goal is reached, then the remaining time will be divided into two parts: maintaining polarized beam for RHIC injection, and AGS study. For the AGS study part, following is the list of agenda:

  1. e880 polarimeter calibration at Ggamma=12.5.
  2. calibration run for both CNI and E880 polarimeter at Ggamma=30.5, 36.5.
  3. injection matching study with both warm snakes on.
  4. ramp measurement.
  5. explore relation of  intensity vs. polarization.