SVX4 User's Manual

FERMILAB-TM-2317-E
Test Results for the SVX4 Version A/B Chip D∅ Note 4251
clock and then for a 396 ns front end clock which corresponds to the operating frequency
when installed in the detector. We have also confirmed with the oscilloscope that the
dynamic range of the preamplifier is greater than 200 fC.
2.2.1 Operation at 132 ns
In Figure 4 and Figure 5, we show the gain as a function of the external capacitance for
four independent channels with different values of the external capacitance. The gain
rises for the larger external capacitances because the preamplifier does not have enough
time to integrate all the charge. The corresponding values are given in Table 2 and Table
3.
Effective Gain (CDF mode)
Effective Gain [e/ADC]
1800
1700
1600
1500
1400
1300
1200
1100
1000
900
800
0 10 20 30 40 50
Capacitance (pF)
BW=0
BW=5
BW=10
BW=15
Figure 4 Effective gain as a function of external capacitance in CDF mode for a front end clock
period of 132 ns. The curves begin to rise for higher capacitances because the amplifier does not
have enough time to integrate the total charge injected. The ramp range was set to 1 and the
digitization frequency is 50 MHz.
BW \ C 10 pF 20 pF 30 pF 40 pF
0 997.9 1034.6 1075.3 1108.9
5 1003.6 1075.8 1155.4 1266.9
10 1033.1 1144.1 1272.6 1439.5
15 1090.8 1261.2 1449.4 1678.6
Table 2 Effective gain as a function of the external capacitance in CDF mode for a front end clock
period of 132 ns. All gain values are in electrons per ADC count.
D∅ RunIIb Group Page 6 6/20/2005