# Presentation: 816237

## Injector PP Setup Plan and Status

- November 18, 2008

- Haixin Huang

## 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.

- Haixin Huang

## 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 (>8.95).  (Working on the modeling)
- Installation of two tune jump quads to mitigate the polarization loss due to horizontal resonances.
- Change RF setup from h=12 to h=6 to reduce space charge effect (more important due to expected smaller emittances).

- Haixin Huang

## LEBT/MEBT Upgrade Status   

- 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 (>90% 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.

**(from Deepak)**

- Haixin Huang

## 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.

- Haixin Huang

## 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 (h=12), we may switch to h=6 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 (>8.95). 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 won’t be ready on day one. The gain on polarization is hoped from smaller emittance out of linac and better matching at AGS injection.

- Haixin Huang

## Backup Slides

- Haixin Huang

## Run6 Polarization vs. Intensity

**Run6 Polarization vs. Intensity**

- 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: x=9.21+2.30*I; y =7.90+4.13*I, where I is intensity in unit of 1011.

**model**

**fitting**

- Haixin Huang

## Spin Tune and Qy vs G

**(Courtesy of  Nick)**