Tune Measurement in RHIC

Brennan, M.J.; Cameron, P.; Cerniglia, P.; Connolly, R.; Cupolo, J.; Dawson, William C.; Degen, C.; Dellapenna, A.; DeLong, J.; Drees, A.; Gassner, D.; Kesselman, Martin; Lee, R.; Marušić, A.; Mead, J.; Michnoff, R.; Schultheiss, C.; Sikora, R.; Zeijts, J. van

doi:10.1063/1.1524396

Cited by 2 publications

(1 citation statement)

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“…Tune-shift effects from various sources can drive the beam to cross resonances and degrade the beam, decreasing the performance of storage rings. Measurement of the betatron tune in rings has been improved in recent years by application of lock-in techniques involving driving the beam directly on the resonance and measuring essentially an S 21 transfer function [6,7,8]. Locking to the frequency for peak S 21 , RHIC with its hadron beam and no significant synchrotron light damping, and PEP-II with its high-current, feedback stabilized beam of electrons with heavy synchrotron light damping are both able to make similar measurements.…”

Section: Betatron Tune Monitoring In Ringsmentioning

confidence: 99%

Beam Diagnostics Based on AC Modulation of System Parameters

Tiefenback¹

2004

AIP Conference Proceedings

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To improve the performance of operating accelerators, quantities such as lattice functions, beam transfer functions, betatron frequencies, etc, can be measured turn by turn with beam position monitors or from difference measurements using step changes in system parameters. Spectral measurements in closed orbit machines provide accurate values for some properties. But for open-ended systems and some measurements in closed-orbit machines, periodic modulation can be very useful for obtaining information about the beam line. Using examples from existing machines, we compare and contrast beam based modulation techniques and step function or passive measurements. For example, large amplitude dipole modulation in rings [1] can be used in dedicated exploration of nonlinear optical properties without beam degradation, even allowing for tune spread effects. Low-level modulation can provide real-time system monitoring with no adverse effect on beam users. Examples considered include fully resonant dipole modulation in storage rings such as RHIC (hadrons) and PEP-II (electrons), and the continuous low-level modulation used in the CEBAF recirculating electron linac for real-time feedback to improve availability.

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Section: Betatron Tune Monitoring In Ringsmentioning

confidence: 99%