Physics307L:People/Mondragon/Notebook/071024

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note: power for LED is from - to +, not gnd to +

Verified the LED works power supply is Harrison Labroratories ewruhdkjdf GSA prop. 00029

PMT Voltage at -1900 V

We set the voltage to the pulser so we get 10.03+/- 0.02 khz


THE tAC SEEMS TO WORK, ADDING A DELAY TO THE SIGNAL SEEMS TO MAKE THE TAC OUTPUT A BIGGER SIGNAL the delay that the delay box puts into the signals is unnoticable on anb o-scope

Speed Of Light

(week 1)

NOTES:

Set up as described in the lab procedure. Tomas and I verified that the PMT was operating (green light seen).

Set Up

LED pulser voltage: 153.9

With the O Scope, we verified the start and stop TAC signals. We also measured a pulse frequency of 8.4kHHz. We adjusted the PMT voltage to get the pulse frequency of exactly 10.01kHz (+/- .02kHz)

System Calibration: We will use the delay box got measure the insertion loss. The TAC seems to be working and we confirmed the delay box works by using the MCA. The histogram shifts when a delay switch is turned (YES!). After configuring the MCA we started taking cal data

TAC Settings/High Voltage for PMT

Range = 100

Multiplier = 1

SCA Window = 811

SCA Lower Level = 48

Start and Stop = Anti

Output = Out

Voltage = 1500 + 497.1

Calibration Data (needed or "Time Walk")

Time Centoid FWHM
4ns 24.133 12.161
8ns 67.79 14.938
12ns 108.2 13.329
16ns 153.7 14.874
20ns 192.6 14.841
24ns 236.4 17.610
28ns 276.5 15.903
32ns 323.0 23.378
36ns 360.3 18.118
40ns 404 21.038
44ns 444.4 19.412
48ns 490.5 25.0955
52ns 530.1 21.614
56ns 573.3 25.081

The curves we were seeing from the MCA looked Poissonish.

Calculations

important!!! FWHM is not the error . It is related, however,

Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://api.formulasearchengine.com/v1/":): {\displaystyle \mathrm{FWHM} = 2 \sqrt{2 \ln (2) } \; \sigma \approx 2.355 \; \sigma. }

Time Centoid FWHM Centroid error
4ns 24.133 12.161 28.637
8ns 67.79 14.938 35.18
12ns 108.2 13.329 31.4
16ns 153.7 14.874 35.0
20ns 192.6 14.841 34.9
24ns 236.4 17.610 41.5
28ns 276.5 15.903 37.4
32ns 323.0 23.378 55.0
36ns 360.3 18.118 42.7
40ns 404 21.038 49.5
44ns 444.4 19.412 45.7
48ns 490.5 25.095 59.1
52ns 530.1 21.614 50.9
56ns 573.3 25.081 59.1

Linefit/ Channel number to time conversion

Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://api.formulasearchengine.com/v1/":): {\displaystyle channel\,number=(10.53 \pm 0.69 \tfrac{channels}{s})(time\,delay) -(17.29 \pm 19.54)channels} Spdoflghtcalibrate.png Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://api.formulasearchengine.com/v1/":): {\displaystyle time \, delay=(0.09495 \pm 0.00626 \tfrac{s}{channel})(channel\,number) -(1.641 \pm 1.861)s}

second week