Download - MuTr Chamber properties
MuTr Chamber properties
K.Shoji
Kyoto Univ.
Measurement of MuTr raw signalUse oscilloscope & LabView
Read 1 strip
HV 1850V
Gas mixture Ar:CO2:CF4=50%:30%:20%
Total resistance
10kohm
Typical Pulse Shape
Fit to these region
Ground Level Noise Subtract
Event-by-event ground level noise subtract
Use linear function y=gradient*x+intercept
3000 samples
Decay time
Detector Capacitance C
Total ResistanceR=9800ohm ~ 10Kohm
Exp(-t/CR)
Fit Error <300nsec
CR ~ 2.8usec C⇒ ~ 300pF (?)
Pulse Height and Charge distribution
Distribution of 1 StripTypical Charge is 200fCBut I used narrow scintillator for trigger,These distribution has dependence of place
Pulse height
chargePulse Height Charge
Correlation of Pulse Height & Charge
There is clear correlation.But little bit rise where pulse height is lowBecause of the Noise?
Simple Model
Cross mark isProfile of pulseheight&charge
Red is Model Line
ASD Chip for MuTr LL1 Trigger
4 Channels for 1 Chip
Input Impedance 370ohmPreamp Integration Time 80nsecPreamp gain 0.8mV/fCENC 2000electrons for 300pF⇒Analog output
Main amp gain 7Comparator with LVDS outputThreshold voltage : common for all 4 channels⇒Digital output
Expected Response of ASD Chip
Input Impedance 370ohm
Preamp Integration Time 80nsec
Preamp gain 0.8mV/fC
C ~ 300pF ⇒ CR ~ 110nsec
Analog outputRise time : few ~ 10nsec
Linearity of ASD Chip1Kohm load
Linearity of Analog output is wrong where charge>500fC
From now…
• Correlation with neighbor strips• Try to Change HV or Gas mixture• Time Response
Leading edge fluctuation from ion drift time<100nsec• ENC 2000electrons for 300pF
~ 0.3fC
Requirement is less than 1%• Can we get 100um resolution with ASD Chip?