APEX ReportAPEX ReportMarch 3March 3,, 2010 2010

Fulvia PilatTime Meeting, March 9, 2010

10 Hz Global Orbit Feedback System10 Hz Global Orbit Feedback SystemFirst Beam ResultsFirst Beam Results

R. Michnoff, P. Cerniglia, L. DeSanto, C. Folz, C. Ho, R. Hulsart, A. Jain, Y. Luo, W. MacKay, G. Mahler, W. Meng, K. Mernick, M. Minty, P. Popken, V. Ptitsyn, J. Ritter, P.

Thieberger, A. Weston, P. Ziminski

Purpose of the System Purpose of the System To provide global orbit correction of the beam perturbations around 10

Hz. 36 BPM measurements and 12 dedicated corrector magnets will be

used for each ring

Configuration for the first APEX test Magnets:

3 new steel-laminated core magnets installed in the blue ring on the Q3 vacuum tees at 5, 6, and 7 o’clock

1 air core magnet in the blue ring near the 8 o’clock Q3 1 air core magnet in the blue ring near the 7 o’clock Q3 (used for inducing 10

Hz on beam)

BPM’s: bi5-bh3, bi5-bh1, bo6-bh1, bo6-bh3, bo7-bh3, bo7-bh1, bi8-bh1, bi8-bh3

Typical New Steel Laminated Core MagnetTypical New Steel Laminated Core MagnetInstalled in RingInstalled in Ring

First Tests: BPM’sFirst Tests: BPM’s

BPM measurements were monitored via GPM using the new BPM data distribution network and ML-510 Xilinx processor hardware RESULT: all 8 BPM’s displayed expected data

microns

1000 samples at approx 5 ms interval; approx 5 sec period

Data read from ML-510 ADOs for:bi5-bh3, bi5-bh1, bo6-bh1, bo6-bh3, bo7-bh3, bo7-bh1,

bi8-bh1, bi8-bh3while exciting beam with 7 o’clock air-core magnet at 10

Hz, +/- 6 Amps

First Tests: MagnetsFirst Tests: Magnets

Excited each magnet with 10 Hz, +/- 6 amps, and monitored result with ML-510 BPM data. RESULT: all magnets modulated beam as

expected.

microns

1000 samples at approx 5 ms interval; approx 5 sec period

6 o’clock steel magnet turned ON

at 10 Hz, +/-6 amps

First Tests: feedbackFirst Tests: feedback

Excited blue beam with 7 o’clock air-core magnet (10 Hz, +/-6 amps), and attempted to close feedback loop. RESULTS

Clear 10 Hz damping noted when looped closed with 7 o’clock steel magnet only.

Damping not apparent when all 4 corrector magnets were ON.

microns

Feedback turned ON using 7 o’clock steel magnet only. 1000 samples at approx 5 ms interval; approx 5 sec period

7 o’clock air-core magnet driving beam for full duration of this period (10 Hz, +/- 6 Amps)

BBA APEXBBA APEX Todd Satogata, Jordan ZieglerTodd Satogata, Jordan Ziegler

Objective was to take beam-based alignment measurements of all yellow low-beta Q1/Q3 BPM’ s, sharing beam at injection with 10Hz orbit feedback personnel by splitting WFG managers

Some crosstalk tests from 10Hz orbit feedback slowed us down, but we were still able to debug and get a full data set in yellow

Method: Measure orbit feed-down from quadrupole variation with -6,-4,-2,0,2,4,6 mm bumps in quad/bpm

One objective is speed: we can get BBA data for each BPM in under 5 minutes, so all 16 IR6/8 planes can be done in 90 minutes

Jordan is working on automated analysis; done by hand now

Request: ~60 minutes at injection in blue to complete blue IR BPMs

Mar 5 2010

RHIC BBA APEX 10

Some Feb 3 results: bo7-bh1Some Feb 3 results: bo7-bh1

From Jordan: Consistent with bo7-bh1 BBA offset of about -200 um

APEX: Chromaticity Feedback 03/03/10

01/08/10

Marusic, Minty, Tepikian

blue ring, ramp chromaticity measurement

yellow ring, ramp chromaticity measurement

x yx y

Qx

Qy

Qx

Qy

previously: verified data integrity in the both rings (including absence of instrumental sign flips):

since then: more chromaticity algorithm improvements code modifications for - interaction with persistent-current compensation - RTDL 23-bit limit

APEX 03/03/10: successful demonstration of

simultaneous tune, coupling, and chromaticity feedback (at injection energy)

x

y

setpoint

Effect of yellow tails on blue (E-lens) Effect of yellow tails on blue (E-lens) Montag, Drees Montag, Drees

Injection: collisions found in STAR but not Phenix

Start scrapingIn yellowStart scrapingIn yellow

CollimatorsAt ~1.7 sigmaCollimatorsAt ~1.7 sigma

CollimatorsAt ~3 sigmaCollimatorsAt ~3 sigma

Blue beam decay improvesafter retracting the collimators

That is not great news for theE-lens if confirmed.

Need to repeat study at store

Blue beam decay improvesafter retracting the collimators

That is not great news for theE-lens if confirmed.

Need to repeat study at store

33rdrd integer integerBai, Marr, Marusic, Minty, SchoeferBai, Marr, Marusic, Minty, Schoefer

•11836: 6x6 Chromaticity measurement

•11837: 12x12 Chrom changes based on previous.

•11838: 23x23 Swing away from resonance 10 seconds early, more chrom changes

•11839: 23x56 Blue transition limited, blue transition chrom changes, a few early yellow chrom changes.

•11840: 111x111 Lost at t280, blue losses shoot up.

•11841: 56x56 Back away blue 0.001, Lost slightly later at t300, same symptoms, just delayed

Conclusion: relax beta* on the ramp (will test ramp tomorrow)If viable the final beta* can be squeezed at store.