1. APEX Report April 28-29, 2009 May 4, 2009 Fulvia Pilat Time Meeting, May 12 2009

2. APEX Schedule April 28-29 2009 5am9pm7pm11:30pm Injection 08-29, 08-10 Polarimeter study Huang, Zelenski +team 2am Ramps BBQ 09-26 DA measurement with AC dipole Bai Pilat 7am Injection BBQ 10 6 turn BPM AC dipole 07-19, 07-20 Noise from Main PS Schultheiss Minty 09-05 D0-DX study MacKay Satogata 08-08 Long Range beam-beam Fischer +team Store BBQ Injection

3. APEX Schedule May 4 th 2009 9amnoon Injection 3pm Ramps BBQ 4pm 07-19, 07-20 Noise from Main PS Schultheiss Wilinsky 09-05 D0-DX study MacKay Satogata

4. RHIC/AGS Polarimeter Study Fixed target polarization for two intensities (1.4 and 1.6*10 11 ) with 12 bunches in both rings with two polarimeters. AGS measurements were done with similar intensity. Polarization profile measurements were done with both rings and both planes with 56 bunches. AGS horizontal and vertical profiles were taken the same time. Sweep and fixed target measurements were done with 56 bunches for comparison. Note: Keith tuned emittance down for AGS before the study, we did not see much change on AGS IPM or CNI target scan, but the polarization profiles measured in AGS is flatter than before. Huang, Zelenski+team

5. Polarization Profiles of RHIC and AGS Ring Horizontal P 0 sigma Vertical P 0 sigma AGS 60.453+-3.341 3.981+-1.909 60.979+-2.374 3.994+-1.491 Blue 55.915+-2.623 3.462+-1.25860.089+-1.860 4.804+-2.294 Blue 64.523+-1.631 3.386+-0.427 Yellow 58.923+-1.162 3.732+-0.500 57.904+-1.661 3.482+-0.447 The profiles are consistent between AGS and RHIC with the statistics. The  actually is  P /  I. These numbers from last year at 100GeV are averaged 2.5, this year is about 3(average of many fills). Given the large error bars, I can’t say there is profiles developed in RHIC ramp.

6. PS beam noise - summary Four ramps were executed with different configurations of the electrostatic shield and a capacitor across the grounding resistors. Schultheiss, Minty

7. Ramp 1 Results

8. Conclusions Floating the Electrostatic Shields in the Dipole Ramp PM reduced the noise during the ramp. Yellow showed more reduction than Blue. The Capacitor had a less dramatic reduction in the noise. The present configuration is with the shields floating and no capacitor.

9. Plan for the experiment Use pattern BBLR_34x34 (28x28 + 6 non-colliding bunches), 2e 11 /bunch, accelerate and collide, will not ramp up the RF voltage CNI emittance measurement => emittances measured around 35 (Blue) and 22 (Yellow) mm.mrad : BBQ was left one during the ramp 5A, position scan in Blue and Yellow, orbit and BTF measurements Retract, CNI emittance measurement => around 50 (Blue) and 22 (Yellow) mm.mrad 50A, position scan in Blue and Yellow, orbit and BTF measurements Retract, CNI emittance measurement Time permitting, change chromaticity, repeat one scan Fischer Robert-Demolaize Calaga

11. Conclusion Plan executed: distance scans with both 5A and 50A scans in both beams, including head-on beam-beam. Suffered from larger than usual emittance (about 30 mm.mrad); BBQ should be off next time. Additional beam time to study in details the behavior of non-colliding bunches + chromaticity changes ?

12. MacKay, Satogata

15. APEX Schedule May 12-13 2009 5am10pm7pm1am Injection High intensity 3am 09-17 Space charge and Beam-beam Fedotov + team 7am 09-06 Off-momentum beta-beat Calaga Glenn 08-08 Long Range beam-beam Fischer Demolaize +team Store BBQ Injection High intensity Gamma-T No snakes 09-21 Bunch length limit Ptitsyn+ team 09-07 Impedance Calaga