AGS pp Status June 12 2009 RSC Meeting

  • Slides: 8
Download presentation
AGS pp Status June 12, 2009 RSC Meeting Haixin Huang

AGS pp Status June 12, 2009 RSC Meeting Haixin Huang

What Have Been Done So Far • • • What have been done so

What Have Been Done So Far • • • What have been done so far to improve polarization: • Qx~ ½ integer injection in the Booster. This reduced emittance in the Booster. • Higher Qy before Ggamma=5 (Qy >8. 96 after 200 ms). This should avoid the first weak vertical intrinsic resonance when acceleration is slow. • Injection damper is on to reduce coherence motion. • Tuning Bt. A and Lt. B to get beam emittance smaller. AGS model related works: • measuring beta functions (relative) at various compensation quads with snake on/off • Optics measurements with cold snake/warm snake on/off at injection (user 3) • Tune jump quads on at injection with DC current Polarization Scan • Detail polarization vs. Qy at 0+, 36 -, 36+, and 12+. • Intensity scans with Booster scraping, chopper width, longitudinal scraping. Not much difference with the first two, the third one gives lower polarization overall, but flatter intensity dependence. • Scan harmonics sin 9 v at 36 - and 36+. • Scan RF voltage at flattop. It showed interesting dependence (lower RF voltage, higher polarization with higher event rates). • Horizontal and Vertical polarization profiles • Polarization ramp measurements on the up and down ramps. 2 Haixin Huang

AGS Emittances The beam emittance (rf off at flattop) are smaller now from run

AGS Emittances The beam emittance (rf off at flattop) are smaller now from run 6: 2/19/08 H 16 p, V 13 p with 1. 3*1011 inj. on the fly 3/06/08 H 13 p, V 17 p with 1. 4*1011 inj. with front porch 5/11/06 H 11. 4 p V 16 p with 1. 6*1011 5/12/06 H 10. 4 p V 15. 2 p with 1. 36*1011 6/05/09 H 10. 5 p V 14. 5 p with 1. 6*1011 6/05/09 H 9. 5 p V 11. 2 p with 1. 4*1011 3 Haixin Huang

Status As of Now • Some improvement of emittance over past a few weeks.

Status As of Now • Some improvement of emittance over past a few weeks. Maybe it’s time to take another polarization profile measurement. • Polarization measurements on the down ramp is done. Waiting for another set of measurements on the up ramp. • The focus recently is on the preparation of horizontal tune jump. How accurate we can achieve on the Ggamma values? We have tried a new field scan with not so flat Ggamma and tune on the flattop. Improvements have been made to turn off extraction bump and by scanning horizontal tune with different momentum spread. There remains question that if the GCC calibration we got at flattop can be applied to the ramp (Bdot effect). • There are indications that the Si detectors are noisier now. We will replace them next Wednesday. As we need reproducible polarization measurements for the tune jump setup. 4 Haixin Huang

Tune Jump Status • One Power supply will be ready today. Another one is

Tune Jump Status • One Power supply will be ready today. Another one is ready next Monday. • Control Application is under final check. • Accurate timing is critical for the tune jump. • Efforts have been put in to calibrate the Ggamma vs. time at flattop ( and will be translated to the ramp). • Before we apply it to the full ramp, a test at a lower energy is planned. • We have built a lower energy flattop at Ggamma=7. 5 to test the tune jump scheme. Polarization measurements have been done without tune jump. 5 Haixin Huang

B Field Scan around Ggamma=46 6 Haixin Huang

B Field Scan around Ggamma=46 6 Haixin Huang

Horizontal Tune Scan Ggamma=46 7 Haixin Huang

Horizontal Tune Scan Ggamma=46 7 Haixin Huang

Why We Need to Change Si Detectors 8 Haixin Huang

Why We Need to Change Si Detectors 8 Haixin Huang