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sTGC (40x60 ) integration with VMM1. V. Smakhtin A. Khodinov. 03.03.2014. Cosmic setup uses VMM1 Configurator. Self-triggered, no scintillators! sTGC chamber 40x60 Analog Signal through VMM1 monitoring channel Digital through special probe.
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sTGC(40x60) integration with VMM1 V. Smakhtin A. Khodinov 03.03.2014
Cosmic setup uses VMM1 Configurator Self-triggered, no scintillators! sTGC chamber 40x60 Analog Signal through VMM1 monitoring channel Digital through special probe
Configurator to control 48 VMM1sData acquisition only 4 channels by Agilent Technologies
Noise status: March 2014 Fluctuation between spills -> noise Fluctuation with periodic pickup-> 10*noise Layer1 Pad of Channel 6 Analog signal at ch 3 Trigger on Digital ch4 Nominal threshold 230 ADC Statistics 100
Dead/good channels Layer1 as of March 2014 Many channels not working! Make sure the channels are Ok to build a tower of 4 pads!
How to define threshold in trigger mode? Vary threshold to catch 50kHz Why 50 kHz as reference? Better idea? Say, signal width is 25 ns 3out of 4 will provide trigger at 1 Hz Cosmic events at 5 Hz Threshold = 737 ADC
Minimum thresholds in Mexico WIS March 2014 Threshold in ADC counts, but needed in mV or fC to compare with G. L. VMM1 data
VMM1:Measured and calculated RMS noise for various Gains and Integration times sTGC Pads Measured noise above 15k ENC on real pads, expected below 5k ENC
Use built-in VMM1 pulse generator 6kHz Generator with fixed pulse rate Real detector connected ~200pF Agilent measured amplitude 325 mV 387 ADC -> 325 mV
Min thresholds in mV 25 ns: Dynamic range drops from 73% at Gain 1 mV/fC to 40% at 9 mV/fC
Min thresholds in fC For comparison translate 100 ns mode into ENC : 20 fC -> 100k ENC !!! Possible to reduce essentially if periodic pick-up eliminated
Summary • VMM1 Noise level measured as of march 2014 Real noise = 3-5 times noise expected by G-L • Thresholds depends on periodic pickup • Proposed threshold conversion ADC->mV • Eliminating 250kHz noise in Mexico possibly help: to match VMM1 noise level to reduce thresholds -> e.g. improve dynamic ranges • On going: time resolutions dead times efficiencies other layers inspection for dead channels