MiniPrototype CAEN V792 Calibration

I injected a signal into the Drift chamber preamps and read it out using the CAEN V792 ADC.

12/11/07

50 dB attenutation signal

The preamp input signal of XX mV was attenutated 50 dB. The preamp output from both drift chambers was sampled with the ADC. Both Drift chambers HV's were unplugged and the preamp was powered to 5.8 V.

Run 192

200 px

Run 193. Preamp HV off

Run 194 Preamp Off, trigg rate changed from 10 Hz to 60 Hz

Run 195 Preamp Off, trigg rate changed from 10 Hz to 550 Hz

Run 196 Preamp Off, trigg rate changed from 10 Hz to 250 Hz

Run 197 Preamp Off, trigg rate changed from 10 Hz to 300 Hz

7 mV Signal

Here is a scope picture of the signal coming out of the preamp and going into the ADC (Blue) as well as the integration gate used. The signal is about 7 mv as shown below. There is a 2 mv peak to peak noise level which has structure.

[math]Q=I \Delta t = \frac{V}{R} \Delta t = \frac{\mbox{Area of trace}}{R} = \frac{2 \times \frac{1}{2} (20 ns) (7 mV) + (36 ns) (7 mV)}{50 \Omega} = (7.84 \pm 2) \times 10^{-12} coul[/math] Error estimate of 25 % is just a guess

The data was then collected using coda and recorded as run #189. A histogram of channel #1 is shown below.

Signal - Ped =[math] (343.5 \pm 0.9 ) - (56.18 \pm\lt 0.3) = 287.3 \pm \sqrt{0.9^2 + 0.3^2} = 287.3 \pm 0.9[/math] Channels

ADC conversion [math]= \frac{7.84 \pm 2 \times 10^{-12} \mbox{Coul}}{287.3 \pm 0.9 \mbox{Chan}} = 27 \pm 7 \; \frac{f\mbox{Coul}}{\mbox{Chan}}[/math]

I was expecting [math] 100 \frac{f\mbox{Coul}}{\mbox{Chan}}[/math]. The signal was split between the ADC and the Scope so there is a factor of 2 but this stil comes up short.

20 mV signal

Reducing the attenuation, a 20 mV signal was sent into the ADC.

[math]Q=I \Delta t = \frac{V}{R} \Delta t = \frac{\mbox{Area of trace}}{R} = \frac{2 \times \frac{1}{2} (20 ns) (26 mV) + (36 ns) (26 mV)}{50 \Omega} = (29.12 \pm 7) \times 10^{-12} coul[/math] Error estimate of 25 % is just a guess

The data was then collected using coda and recorded as run #190. A histogram of channel #1 is shown below.

Signal - Ped =[math] (542.2 \pm 1.1 ) - (101.8 \pm\lt 2.5) = 440.4 \pm \sqrt{1.1^2 + 2.5^2} = 440.4 \pm 2.7[/math] Channels

ADC conversion [math]= \frac{(29.12 \pm 7) \times 10^{-12} \mbox{Coul}}{440.4 \pm 2.7 \mbox{Chan}} = 66 \pm 16 \; \frac{f\mbox{Coul}}{\mbox{Chan}}[/math]

I was expecting [math] 100 \frac{f\mbox{Coul}}{\mbox{Chan}}[/math]. The signal was split between the ADC and the Scope so there is a factor of 2. This would put the conversion to [math](132 \pm 33\frac{f\mbox{Coul}}{\mbox{Chan}})[/math] in agreement with manual.

100 mV signal

Reducing the attenuation, a 100 mV signal was sent into the ADC.

[math]Q=I \Delta t = \frac{V}{R} \Delta t = \frac{\mbox{Area of trace}}{R} = \frac{2 \times \frac{1}{2} (20 ns) (110 mV) + (36 ns) (110 mV)}{50 \Omega} = (123.2 \pm 30) \times 10^{-12} coul[/math] Error estimate of 25 % is just a guess

The data was then collected using coda and recorded as run #191. A histogram of channel #1 is shown below.

Calibration

Plastik's output is going into channels 1-7 and Metalicas output into 10-16. Drift Chamber High Voltage is off and preamp is powered to 5.8 volts. The post amp is not being used.

Input (mV)	Chan 1	Chan 2	Chan 3	Chan 4	Chan 5	Chan 6	Chan 7	Chan 8	Chan 9	Chan 10	Chan 11	Chan 12	Chan 13	Chan 14	Chan 15	Chan 16
0
7
20
100	1538	1625	1666	510	1640	1661	648	648	605	1640	1685	1672	1684	1611	1084	587