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Injector PP Setup Plan and Status. Haixin Huang. November 18, 2008. 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.)
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Injector PP Setup Plan and Status • Haixin Huang November 18, 2008
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
(from Deepak) 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. 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 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: x=9.21+2.30*I; y =7.90+4.13*I, where I is intensity in unit of 1011. Haixin Huang
Spin Tune and Qy vs Gg (Courtesy of Nick)