Difference between revisions of "Calibrating GEM detector"

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Latest revision as of 05:12, 17 June 2013

Amplifier effect on the signal

Ortec 474 timing filter amplifier amplifies the signal from the trigger output.The amplification will make a shift in the channel number compared to the same signal without application. To determine exactly the shift in channel number after the amplification, a choice for an input signal amplitude to charge the ADC just above noise, then amplifying the same input then recording the channel number (if possible). For example, generating a pulse of 0.1 V amplitude with an offset of 0.06 V using stanford research system pulse generator DG535 will hit channel 291 +_0.34 (run#4829), after the amplification it hits channel number 3767 +_0.78. Input pulse for the attenuator is 1.80V +_ 0.045, and the attenuator output pulse is 222 +_ 2.5 mV (factor of 8.1) when is set on 17.5 dB.

Amp + att. 04/26/13

Run Number attenuation (dB) Amplification Average channel Number Average channel Number - Noise (79) calculated gain Notes
4853 0 0 880 801 0 reference for the next two
4854 2 0 553 474 4.6
4855 4 0 304 225 11.0
4860 0 0 3399 3320 0
4861 14 0 98.46 19.46 44.6
4862 0 0 3514 3435 0
4863 14 0 133 54 36.1
4868 0 0 3903 3824 0
4869 14 0 114 35 40.8
4872 0 0 2974 2895 0
4846 24.5 yes 436 357 18.2
4848 18 yes 1720 1641 4.9
4849 20 yes 1213 1134 8.1
4850 14 yes 3210 3131 -0.7
4851 16 yes 2365 2286 2.1


Att. 04/27/13

unamplified input pulse passed through an attenuator, the attenuation is changed (without changing the input pulse offset of the input), the results are in the following table:

Run Number attenuation (dB) Average channel Number Average channel Number - Noise (79) calculated gain
4894 0 3653 3574 0
4897 8 1104 1025 10.8
4898 9 916 837 12.6
4899 6 1531 1452 7.8
4898 3 2380 2301 3.8

Amp 04/28/13

Amplified x4 level 4 fine gain


Run Number attenuation (dB) Average channel Number Average channel Number - Noise (79) calculated gain
4905 0 3779 3700 0
4906 3 2580 2501 3.4
4907 6 1776 1679 6.8
4908 9 1124 1045 10.9
4909 12 626 547 16.6
4910 15 287 208 25
4911 18 99 20 42.6


Amp and att. 05/04/13

Amplified x6 level 6 fine gain


Charge channelnumber x6 6.png


With attenuator

Charge channelnumber x6 6 attenuated.png

Mathmatica x6 6 attenuated.png


According to the calibration curve above the charge collected by the ADC is determined in the table above.[https://wiki.iac.isu.edu/index.php/Neutron_TGEM_Detector_Abdel#Run_List3 ]


Att. 05/10/13 & 06/03/13

The table below shows the measurements of the charge of a square pulse that has an amplitude of -0.49 V (osc. 0.504+_ 0 V )with a zero offset and a width of 25.2us. The gate width is 70ns.

[math] Q = Q_0 10^{(L_v/20)} [/math]

Run Number attenuation (dB) Average channel Number Pedestal subtracted Average channel Number calculated gain
5120 0 3876.27 3797 0
5120 3 3057 2977
5123 6 1906 1827
5124 9 1339 1260
5125 12 940 861
5126 14 742 663
data2 06/03/13
5172 0 3818.94 +/- 0.06
5173 3 2685.03 +/- 0.05
5174 6 1889.48 +/- 0.05
5176 9 1322.00 +/- 0.03
5177 12 926.62 +/- 0.03
5178 15 647.03 +/- 0.02

Amp 06/03/13

Amplifier

An amplifier (x6 level 6) was added to amplify the signal before attenuation, a square pulse of an amplitude of (1st time-0.18V) and for (the second time 0.47V) (osc. 235 +_ 4 mV) with a zero offset and a width of 25.8us was used, the gate width was 70ns. After the amplification the signal amplitude is (first time 3.42+_ 0.29 V) (2nd time: gate integrate 4.21 +/-0 V).

[math] Q = Q_0 10^{(L_v/20)} [/math]


Run Number attenuation (dB) Average channel Number Average channel Number - Noise (79) charge collected (nC) calculated attenuation expected attenuation V(mV)
5134 14 3952 3873 1.6552 0 647+_32
5135 15 3503 3424 1.4756 0.997 576+_27
5136 18 2474 2395 1.064 20*log(3952/2472) = 4.2 4 416+_16
5137 21 1752 1673 0.7752 6.589 235+_ 32
5138 24 1206 1127 0.5568 20*log(3873/1127) = 10.7 10 222 +_7
Data2 06/03/13 Pedestal 63
5180 14 2872.76 +/- 0.09 872
5181 15 2477.22 +/- 0.08 782
5182 18 1823.29 +/- 0.08 546
5183 21 1306.90 +/- 0.04 392
5184 24 933.94 +/- 0.03 271

Bat. 05/24/13

ADC calibration using a battery

Using a 1.5V battery connected to to 5 kohm resistor, then 25 ohm terminated ADC. The oscilloscope measures 15 mV DC voltage for the battery as it is 50 ohm terminated.


Run Number channel Number Channel Number - padestal Gate width (ns) Charge (nC)
62 851 771 500 0.015*(Gate width)/25 = 0.3
63 1263 1184 750 0.45
64 1702 1623 1000 0.6
65 1250 2072 2151 0.75
66 2500 3897 3976 1.5


Batttery cal.png

Bat 05/30/13

ADC calibration using a battery

Using a 1.5V battery with a grounded positive terminal connected to to 5 kohm resistor, then 50 ohm terminated ADC. The oscilloscope measured 14.4 mV DC voltage of the battery when it is 50 ohm terminated.


Run Number channel Number +_ error Gate width (ns) charge (nC)
97 865 +_ 0.04 500 =0.0144*(Gate width=500)/50=0.144
98 493+_0.03 250 0.072
101 1283 +_0.03 750 0.216
102 1000
104 2105 +_ 0.04 1250 0.36
106 3317 +_ 0.02 2000 0.576
107 overcharge 2500

Battery grounded cal.png


Measurements Notes

1- The slope of the calibration curve as the ADC is connected to the battery with the positive terminal grounded is 178 pC.

2- The ADC manual manual mentioned 100pC gain/count, does count = channel? Also it is measures max. tolerate voltage >25 mV with +_ 2 mV as maximum voltage offset, the battery provides 14.4 mV offset, Does the ADC measure that the battery voltage or consider it more that the offset limit and measure only within the offset limit?


Today 05/31 the equipment moved to the LDS to start our measurements but I am still thinking how to improve our calibration curve measurements to get the right slope.


Bat. grounded 6/2/13

Measuring the grounded positive terminal battery output again in the LDS, V= 14.7 mV measured by the oscilloscope. (R= 5kohm, V=1.5, I= 1.5/5kohm = 0.3 mA, oscilloscope channel 2 is 46 ohm terminated, then V = 46*0.3mA = 13.8 mV). The ADC noise level in channel 5 (signal channel) is 63 (run #5162) which is 42.1 ohm terminated.


Run Number channel Number +_ error channel Number - Pedestal Gate width width (ns) charge (pC)
5161 356.14 +/- 0.01 293 178 = 14.7*(Gate width)/42.1 = 62.2
5163 712.09 [math]\pm[/math] 0.02 649 398 139.0
5164 1368.60 +_ 0.02 1305 798 278.6
5165 2662.70 +_ 0.02 2600 1592 555.9
5157 3670 +_ 0.01 3607 2216 773.8


Battery grounded cal2.png


Amp 06/04/13

Amplified x6 level 6 fine gain

stanford pulse generator is used as source for a negative pulse of width of 11.8us +/- 3, and the gate width is 32.94 ns +/- 0.02 . all the voltage measurement is recorded by using oscilloscope 46 ohm terminated. So the amplifier input current is (input signal amplitude/46)


Run Number input signal (mV) amplified pulse amp. (mV) +/- SD Charge (pC) Average channel Number Average channel Number - Noise (63)
5205 51 +/- 1 676.702 945 +/- 8 2415.57 +/- 0.13 2352.57
5207 56 +/- 1 744.730 1040 +/- 8 2644.05+/- 0.10 2581.05
5208 60 +/- 1 809.178 1130 +/- 10 2840.40+/- 0.15 2777.40
5209 65 +/- 1 859.304 1200 +/- 8 3066.89+/- 0.18 3003.89
5210 70 +/- 1 916.591 1280 +/- 8 3293.51+/- 0.21 3230.51
5214 80 +/- 1 1045.49 1460 +/- 8 3744.33+/- 0.15 3681.33

Charge cal1 ampx6 level6.png


Two Amp's 06/06/13

Amplified x6 level 6 fine gain and P.S. gain amplifier 777

stanford pulse generator is used as source for a negative pulse of width of 892 ns +/- 4, and the gate width is 32.7 ns +/- 0.6 . all the voltage measurement is recorded by using oscilloscope's CH2 which is 46 ohm terminated. So the amplifier input current is (input signal amplitude/46)


Run Number input signal (mV) amplified pulse amp. (V) +/- SD Charge (pC) Average channel Number Average channel Number - Noise (63)
5253 21.6 +/- 0.3 0.79 +/- 0.01 1847.32 +/- 0.13
5254 23.6 +/- 0.3 0.86 +/- 0.01 2305.25 +/- 0.14
5255 25.6 +/- 0.3 0.94 +/- 0.01 2501.55 +/- 0.12
5256 27.6 +/- 0.3 1.02 +/- 0.01 2696.81 +/- 0.18
5257 29.6 +/- 0.3 1.09 +/- 0.01 2899.58 +/- 0.16
5258 37.3 +/- 0.3 1.40 +/- 0.01 3695.65 +/- 0.14


Cal 2amps 6 6.png

2 Amp's +Att11 06/06/13

Amplified x6 level 6 fine gain, P.S. 777 and attenuated 11 dB

Stanford pulse generator is used as source for a negative pulse of width of 892 ns +/- 4, and the gate width is 34.4 ns +/- 0.6 . all the voltage measurement is recorded by using oscilloscope CH2 which is 46 ohm terminated. So the amplifier input current is (input signal amplitude/46)


Run Number input signal (mV) ADC pulse (V) Charge (pC) Average channel Number Average channel Number - Noise (63)
5278 0.1, 21.6 +/- 0.3 0.204 +/- 0.004 767.25 +/- 0.05
5281 0.15, 32.6 +/- 0.6 0.336 +/- 0.008 950.58 +/- 0.05
5282 0.20, 42.4 +/- 0.6 0.440 +/- 0.004 1235.08 +/- 0.06
5283 0.25, 52.0 +/- 0.6 0.544 +/- 0.004 1521.28 +/- 0.05
5286 0.5, 103 +/- 1 1.12 +/- 0.02 3133.79 +/- 0.08


Cal 2amps 6 6 11dB.png

2 Amp's +Att17 06/09/13

Amplified x6 level 6 fine gain, P.S. 777 and attenuated 17 dB

Stanford pulse generator is used as source for a negative pulse of width of 892 ns +/- 4, and the gate width is 73.4 ns +/- 0.6 . all the voltage measurement is recorded by using oscilloscope CH2 which is 46 ohm terminated. So the amplifier input current is (input signal amplitude/46)


Run Number input signal (mV) ADC pulse (V) Charge (pC) Average channel Number Average channel Number - Noise (63)
5294 0.1, 21 +/- 1 0.204 +/- 0.004 747.63 +/- 0.07
5295 0.15, 32 +/- 1 0.336 +/- 0.008 948.89 +/- 0.05
5296 0.20, 41 +/- 1 0.440 +/- 0.004 1237.31 +/- 0.05
5297 0.25, 51 +/- 1 0.544 +/- 0.004 1539.09 +/- 0.05
5298 0.5, 102 +/- 1 1.12 +/- 0.02 3184.43 +/- 0.06


Cal 2amps 6 6 17dB.png

2 Amp's +Att15 06/09/13

Amplified x6 level 6 fine gain, P.S. 777 and attenuated 15 dB

Stanford pulse generator is used as source for a negative pulse of width of 892 ns +/- 4, and the gate width is 73.4 ns +/- 0.6 . all the voltage measurement is recorded by using oscilloscope CH2 which is 46 ohm terminated. So the amplifier input current is (input signal amplitude/46)


Run Number input signal (mV) ADC pulse (V) Charge (pC) Average channel Number Average channel Number - Noise (63)
5306 0.1, 20 +/- 1 0.204 +/- 0.004 766.08 +/- 0.12
5305 0.15, 31 +/- 1 0.336 +/- 0.008 1214.41 +/- 0.05
5304 0.20, 41 +/- 1 0.440 +/- 0.004 1593.77 +/- 0.06
5303 0.25, 50 +/- 1 0.544 +/- 0.004 1976.82 +/- 0.06
5302 0.35, 71 +/- 1 1.12 +/- 0.02 2835.10 +/- 0.06


Cal 2amps 6 6 15dB.png

2 Amp's +Att8 06/09/13

Amplified x6 level 6 fine gain, P.S. 777 and attenuated 8 dB

Stanford pulse generator is used as source for a negative pulse of width of 892 ns +/- 4, and the gate width is 33.6 ns +/- 0.6 . all the voltage measurement is recorded by using oscilloscope CH2 which is 46 ohm terminated. So the amplifier input current is (input signal amplitude/46)


Run Number input signal (mV) ADC pulse (V) Charge (pC) Average channel Number Average channel Number - Noise (63)
5307 0.1, 20 +/- 1 0.204 +/- 0.004 786.25 +/- 0.12
5308 0.15, 31 +/- 1 0.336 +/- 0.008 1222.02 +/- 0.05
5309 0.20, 41 +/- 1 0.440 +/- 0.004 1588.96 +/- 0.06
5310 0.25, 50 +/- 1 0.544 +/- 0.004 1960.81 +/- 0.06
5302 0.35, 71 +/- 1 1.02 +/- 0.02 2835.10 +/- 0.06


Cal 2amps 6 6 8dB.png



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