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Turn-by-Turn Beam Diagnostic at NSLS

A.Batrakov, S.Kuznetsov, R.Nawrocky, J.Rothman, V.Shilo, J.Smith

The project proposes a turn-by-turn diagnostic system for storage rings. The system measures beam intensity and beam coordinates at each revolution of the circulating beam and provides valuable information on the fast processes within the beam. The turn-by-turn diagnostic equipment based on beam position monitoring system and fast multi-channel dedicated ADC. It could be useful to improve the performance of synchrotron light facilities, increase the injection efficiency and to observe nonlinear beam dynamics as a phase space monitor.

In accordance with collaboration between Brookhaven National Laboratory National Synchrotron Light Source (NSLS), Budker Institute Nuclear Physics (BINP) and Kurchatov Synchrotron Radiation Source (KSRS), the turn-by-turn diagnostic system was designed, installed and tested under the beam at VUV-Ring and X-Ray ring (NSLS).

Figure 1

VME-ADC board takes analog signals from turn-by-turn front-end-electronics. Two output analog signals, derived from front-end-analog board , look like bell-shape pulses with duration of 15-20 ns. These pulses corresponds to one bunch on the orbit. Amplitude of sum-signal is proportional to the bunch beam intensity, and delta-signal is proportional to X-displasement (if X-channel used) or Z-displacement (if Z-channel used).

These signals are fed to 4-channel 12-bits ADC. ADC are clocked by revolution frequency 5.9 MHz (RF/9 for VUV ring) or 1.8 MHz (RF/30 for XRay ring), therefore one sample of sum signal and one sample of delta signal for each plane per one turn will be obtained. Data from ADCs is recorded at on-board FIFO memory with 32 kWords per channel length. Kicker or injection pulse was used as trigger to start the record procedure. Then VME CPU reads the data record and sends it to high level workstation through network.

Software support consists of three parts. First part includes real-time software to control ADC, memory procedures and timing. Middleware software consist of standard NSLS real-time monitor under VxWorks operating system and UCODE library for network connection and data exchanging. High level software based on PRETUNE 'hands control' under HPUX and TADC program under Windows NT. Windows NT server allows connection of X-terminals as a normal 'MS-Windows-style' screen.


Beam studies at VUV storage ring:
Injection study
Kick to stored beam study
Phase-space monitoring ( 2 BPMs)
Beam studies at X-Ray storage ring:
Injection study
Kick to stored beam study
Hardware description:
VME-ADC board
Software description:
MS-Windows NT screen view
HPUX screen view

References

[1] A.Batrakov et al. "Beam Position Monitor With the Digital Signal Processing." Proceedings of the EPAC'96 Conference, Barcelona 1996, pp..

[2] R.Nawrocky and S.Kramer, "Single-Turn Beam Position Monitor for the NSLS VUV Electron Storage Ring", Proceedings of the 1995 Particle Accelerator Conference. Dallas, Texas, May, 1995. pp.

[3] E.Levichev et al. A non-linear beam dynamics experiments at VEPP-4M ring. Proceedings of EPAC'96 Conference, Barcelona 1996, v2.pp.896-898.

For information please contact: Emil Zitvogel zitvogel@bnl.gov