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SNS Fast Beam Loss Monitors Final Design Review. David M. Gassner. BLM System Design Features. Ion Chambers: Wide Dynamic Range (IC 6 Decades) ( 2 dn, 4 up) Gain adjustment (per channel) Beam intensities Detector shielding. Response Time Ion Chamber
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SNS Fast Beam Loss Monitors Final Design Review David M. Gassner SNS Beam Loss Monitor
BLM System Design Features Ion Chambers: • Wide Dynamic Range (IC 6 Decades) (2 dn, 4 up) • Gain adjustment (per channel) • Beam intensities • Detector shielding • Response Time • Ion Chamber • Micro-second response. Data can be available for multi-turn, per cycle, and per second intervals. • Order of 5-10 turns to generate Permit Link Fail(35 KHz BW = 10us) • FBLM, Liquid Cell/ PMT • Fast (ns), within turn loss data • Wide dynamic range • FBLM Test • LED mounted inside Scintillator/PMT assembly • Can be pulsed remotely SNS Beam Loss Monitor
BLM Distribution Total 18 FBLM’s SNS Beam Loss Monitor
HEBT Loss Monitors 169 meters BLM LocationQuantity Quads 37 Collimator 2 Cavities 2 Dump 2 BIG 1 Moveable 8 FBLM LocationQuantity Upstream 1 Bend 1 Dump 1 SNS Beam Loss Monitor
Ring Loss Monitors 248 meter circumference BLM LocationQuantity Quad 44 Injection 7 Collimators 7 RF 5 Extraction 5 Moveable 7 FBLM LocationQuantity Injection 2 Straight Sec. End 4 Bends 4 Extraction 2 SNS Beam Loss Monitor
RTBT Loss Monitors 150 meters BLM LocationQuantity Quads 27 Collimators 4 Dump 2 Target 3 Moveable 4 FBLM LocationQuantity Extraction 1 Collimators 1 Target area 1 SNS Beam Loss Monitor
Liquid Cell/Photo-Multiplier Loss Monitor Detector • Available commercially from Bicron, Model MAB. • BC-505 Liquid (1,2,4 Trimethybenzene) • More Rad hard than plastics, (about 10X’s) • Highest light output of any liquid (80% anthracene) • Excellent light transmission (2.5m, min 1/e attenuation) • High Flash point (48oC, 118oF) • PMT - Hamamatsu 2060, 10 stage. • Sensitivity on order of 100uC/R, Relative to itself. SNS Beam Loss Monitor
Loss Signals • Fast Loss Monitor Applications • Fast instabilities • Kicker errors • Momentum errors • Beam in Gap • Ring wire scanner data • Two Modes • Integrated signal over bunch duration, read out via digitizer clocked revolution frequency. • Losses within bunch. Signals buffered and sent through wideband mux to fast digitizer (1 GS/s). SNS Beam Loss Monitor
FBLM - Liquid Cell & Photo Multiplier SNS Beam Loss Monitor
Data Acquisition & Control Buffer Electronics: • Wideband amp, drives two outputs. Loss Data: • All channels digitized through standard 60 MS/s 14 bit ADC. • Selected channels at 1 GS/s via mux, (Example: LeCroy 374 Scope) • Data transferred to high level via Channel Access. Multiplexer for 1 GS/s: Keithley • 7001 High Density Switch system • 7016A 50 Ohm, Dual 1X4, 2 GHz Mux cards LED Test Pulse • Remote control • Timing HV Bias Control • EPIC’s Driver to ISEG VME based Bias Supply SNS Beam Loss Monitor
HV Bias ISEG HV Bias Supply • VME High Voltage Power Supplies in 2 slot width • 1 channel and 2 channel versions in same dimensions • LCD display for voltage or current • variable rate of change of output voltage • switched polarity • integrated protection and control circuits • output overload and short circuit protected • SHV connector on front side • Full control via VMEbus • EPIC’s drivers • $1.2k/channel • Model VHQ 202M, 0-2kV, 3mA SNS Beam Loss Monitor