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?