beam-beam wire compensation, status and plans
DESCRIPTION
Beam-beam wire compensation, status and plans. W. Fischer N. Abreu, R. Calaga, Y. Luo, G. Robert-Demolaize, BNL ; U. Dorda, J.-P. Koutchouk, F. Zimmermann, CERN ; H.J. Kim, T. Sen, FNAL ; J. Qiang, LBNL ; A. Kabel, SLAC. LARP Collaboration Meeting 9, Fermilab, 17 October 2007. Content. - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Beam-beam wire compensation, status and plans](https://reader035.vdocument.in/reader035/viewer/2022062409/568150f3550346895dbf0dfa/html5/thumbnails/1.jpg)
Beam-beam wire compensation,status and plans
W. Fischer
N. Abreu, R. Calaga, Y. Luo, G. Robert-Demolaize, BNL; U. Dorda, J.-P. Koutchouk, F. Zimmermann, CERN;
H.J. Kim, T. Sen, FNAL; J. Qiang, LBNL; A. Kabel, SLAC
LARP Collaboration Meeting 9, Fermilab, 17 October 2007
![Page 2: Beam-beam wire compensation, status and plans](https://reader035.vdocument.in/reader035/viewer/2022062409/568150f3550346895dbf0dfa/html5/thumbnails/2.jpg)
Wolfram Fischer 2
Content
• Measurement in 2007
• Simulation status
• Measurement plans for 2008
![Page 3: Beam-beam wire compensation, status and plans](https://reader035.vdocument.in/reader035/viewer/2022062409/568150f3550346895dbf0dfa/html5/thumbnails/3.jpg)
Wolfram Fischer 3
RHIC BBLR wires in tunnel
![Page 4: Beam-beam wire compensation, status and plans](https://reader035.vdocument.in/reader035/viewer/2022062409/568150f3550346895dbf0dfa/html5/thumbnails/4.jpg)
Wolfram Fischer 4
Wire operation
Two degrees of freedom:– Current (0 – 50 A)– Vertical position (0 – 65 mm)
• Local PIN diodes (middle of BBLR and downstream end of BBLR)
• Temperature sensors
![Page 5: Beam-beam wire compensation, status and plans](https://reader035.vdocument.in/reader035/viewer/2022062409/568150f3550346895dbf0dfa/html5/thumbnails/5.jpg)
Wolfram Fischer 5
Experiments in RHIC Run-7 (2007)
• No actual long-range compensation – Beam-beam effect too small with Au
• Test effect of wire (= strong long-range beam-beam
effect) on Au beam, to benchmark simulation– At injection ( 10 GeV/nucleon Au beam)
– At store (100 GeV/nucleon Au beam)
• Test effect of wire on collimation efficiency
![Page 6: Beam-beam wire compensation, status and plans](https://reader035.vdocument.in/reader035/viewer/2022062409/568150f3550346895dbf0dfa/html5/thumbnails/6.jpg)
Wolfram Fischer 6
Experiments in RHIC Run-7 (2007)
• Parasitic time– 03/13 0-4am during setup at injection (B)
– 03/27 2:30-3pm during store in collision (B), for background observation
• Scheduled time– 04/11 5:30-8am (permit dropped after BBLR movement)– 04/25 5-8am (B+Y)
– 05/09 5-8am (B+Y)
– 06/20 5-8am (B+Y, lost after 1 h due to abort kicker problem)
![Page 7: Beam-beam wire compensation, status and plans](https://reader035.vdocument.in/reader035/viewer/2022062409/568150f3550346895dbf0dfa/html5/thumbnails/7.jpg)
Wolfram Fischer 7
Distance scan at injection – 5A current, Au beam
![Page 8: Beam-beam wire compensation, status and plans](https://reader035.vdocument.in/reader035/viewer/2022062409/568150f3550346895dbf0dfa/html5/thumbnails/8.jpg)
Wolfram Fischer 8
Distance scan at injection – 50 A current, Au beam
![Page 9: Beam-beam wire compensation, status and plans](https://reader035.vdocument.in/reader035/viewer/2022062409/568150f3550346895dbf0dfa/html5/thumbnails/9.jpg)
Wolfram Fischer 9
Distance scan at store – 50 A, Au beam
See increase in experimental background – no help for collimation.
![Page 10: Beam-beam wire compensation, status and plans](https://reader035.vdocument.in/reader035/viewer/2022062409/568150f3550346895dbf0dfa/html5/thumbnails/10.jpg)
Wolfram Fischer 10
Check tune and orbit response
![Page 11: Beam-beam wire compensation, status and plans](https://reader035.vdocument.in/reader035/viewer/2022062409/568150f3550346895dbf0dfa/html5/thumbnails/11.jpg)
Wolfram Fischer 11
Distance scans: 5, 50 A, Blue, Yellow
![Page 12: Beam-beam wire compensation, status and plans](https://reader035.vdocument.in/reader035/viewer/2022062409/568150f3550346895dbf0dfa/html5/thumbnails/12.jpg)
Wolfram Fischer 12
Current scan: Blue, Yellow
![Page 13: Beam-beam wire compensation, status and plans](https://reader035.vdocument.in/reader035/viewer/2022062409/568150f3550346895dbf0dfa/html5/thumbnails/13.jpg)
Wolfram Fischer 13
Chromaticity scan: YellowLoss vs. vertical chromaticity
Current scan at largest
![Page 14: Beam-beam wire compensation, status and plans](https://reader035.vdocument.in/reader035/viewer/2022062409/568150f3550346895dbf0dfa/html5/thumbnails/14.jpg)
Wolfram Fischer 14
Benchmark simulationsRHIC detailed model includes:• Magnetic field errors in DX,D0,Q1,Q2,Q3• Randomized sextupole errors in arc dipoles• Tune ripple
Simulations by • U. Dorda, CERN• H.J. Kim, T. Sen, FNAL• A. Kabel, SLAC• J. Qiang, LBNL
![Page 15: Beam-beam wire compensation, status and plans](https://reader035.vdocument.in/reader035/viewer/2022062409/568150f3550346895dbf0dfa/html5/thumbnails/15.jpg)
Wolfram Fischer 15
Benchmark simulations
Blue beam at store (Exp. 1, 12.5 Am), U. Dorda
![Page 16: Beam-beam wire compensation, status and plans](https://reader035.vdocument.in/reader035/viewer/2022062409/568150f3550346895dbf0dfa/html5/thumbnails/16.jpg)
Wolfram Fischer 16
Benchmark simulationsBlue at injection, simulated by H.J. Kim, T. Sen
![Page 17: Beam-beam wire compensation, status and plans](https://reader035.vdocument.in/reader035/viewer/2022062409/568150f3550346895dbf0dfa/html5/thumbnails/17.jpg)
Wolfram Fischer 17
Benchmark simulations
30 mm 30 mm
Blue at store, A. Kabel
![Page 18: Beam-beam wire compensation, status and plans](https://reader035.vdocument.in/reader035/viewer/2022062409/568150f3550346895dbf0dfa/html5/thumbnails/18.jpg)
Wolfram Fischer 18
Open items in experiments
• Only Au beams tested with BBLR, proton beams have 2-3 larger beam-beam parameter, and different tunes
• No head-on collisions included in scan
• No attempt to compensate for single head-on interaction
• No pulsed wire tested (under study by U. Dorda)
![Page 19: Beam-beam wire compensation, status and plans](https://reader035.vdocument.in/reader035/viewer/2022062409/568150f3550346895dbf0dfa/html5/thumbnails/19.jpg)
Wolfram Fischer 19
Planned test with RHIC BBLR wires in 2008
• Will ask for 33 hr dedicated time again
• Would like to test effect on background with protons too (parasitic)
• Parameter scans (distance, strength) with protons– Including head-on
– Different working points
• Attempt to compensate one long-range interaction
![Page 20: Beam-beam wire compensation, status and plans](https://reader035.vdocument.in/reader035/viewer/2022062409/568150f3550346895dbf0dfa/html5/thumbnails/20.jpg)
Wolfram Fischer 20
RHIC – possible location for compensation
RHIC Sector 5
yo5
bi5
long-rangeinteraction(vertical)
long-rangecompensation
(up)
long-rangecompensation
(down)
x,y = 6 deg (* = 1m)
IP6
Small phase advance between long-range beam-beam interactionand possible compensator can only be realized at store.
![Page 21: Beam-beam wire compensation, status and plans](https://reader035.vdocument.in/reader035/viewer/2022062409/568150f3550346895dbf0dfa/html5/thumbnails/21.jpg)
Wolfram Fischer 21
Summary – long-range beam-beam in RHIC
• Parasitic measurements done with Au beams in 2007:– At injection– At store with colliding beams
• Dedicated experiments with Au beams at store (100 GeV/n):– Loss rate vs. distance– Loss rate vs. wire strength– Loss rate vs. chromaticity
• Simulations for 2007 experiments coming to conclusion
• Experimental plans for 2008:– Parameter scans with p-beam (including head-on, new tunes)– Attempt to compensate single long-range interaction