Difference between revisions of "Start Counter Operations"
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Instead of looking at the ADC response as a function of z bin one can also look at some selected z bins 15(z=60+30cm), 12(z=60+24cm), 8(z=60+16cm) and looking at the response as a function of Run number. This is a better view to see how the response changed over time. The plots are in groups of 5 paddles per pad. There is some non negligible variation within a given Run Period. But a general trend can be identified that the signal response gets smaller over time.<br> | Instead of looking at the ADC response as a function of z bin one can also look at some selected z bins 15(z=60+30cm), 12(z=60+24cm), 8(z=60+16cm) and looking at the response as a function of Run number. This is a better view to see how the response changed over time. The plots are in groups of 5 paddles per pad. There is some non negligible variation within a given Run Period. But a general trend can be identified that the signal response gets smaller over time.<br> | ||
| − | [[File:sc_paddle_response_BIN15.gif]] | + | <b>BIN15: z=90cm</b> <br>[[File:sc_paddle_response_BIN15.gif]]<br> |
| + | <b>BIN12: z=84cm</b> <br>[[File:sc_paddle_response_BIN12.gif]]<br> | ||
| + | <b>BIN08: z=76cm</b> <br>[[File:sc_paddle_response_BIN8.gif]]<br> | ||
=== Plots of Start Counter response === | === Plots of Start Counter response === | ||
Revision as of 14:54, 25 October 2023
Start Counter Response
Performance studies of the start counter over time. As is shown in plots below in terms of the response of the start counter paddle to hits in the nose cone is much stronger (yielding more photons) than in the straight section. Also, there is not much of a variation seen in the response for hits along the straight section. However, the mean detector response did degrade over time over the full length of the individual paddles. In general the mean detector signal peak in the straight section degraded from about 400 ADC counts in Run Period 40k to about 200 ADC counts in Run Period 120k with a larger variation from paddle to paddle. Similarly, the response in the nose section degraded too, where the degradation is also seen to be about a factor of 2. To illustrate this finding two plots are shown below of the mean Start counter response as a function of z position along the paddle (in units of "bins") for run 41388 and run 120848:
Overall, a degradation in the amplitude of a factor of 2 is seen. Note that the bias voltage has never been changed and is still the same value as at the start of GlueX operation.
Instead of looking at the ADC response as a function of z bin one can also look at some selected z bins 15(z=60+30cm), 12(z=60+24cm), 8(z=60+16cm) and looking at the response as a function of Run number. This is a better view to see how the response changed over time. The plots are in groups of 5 paddles per pad. There is some non negligible variation within a given Run Period. But a general trend can be identified that the signal response gets smaller over time.
BIN15: z=90cm 
BIN12: z=84cm 
BIN08: z=76cm 
Plots of Start Counter response
- Detector response as a function of z location over time. The z-bin starts with 60cm and each bin covers 2cm so bin 2 is 62-64 cm and bin 17 is 84-86 cm. As an example paddle 3 bin 7 and bin 15 are compared between run 41835 and run 90660. It is clear that in the nose section (bin 15) the response is much larger (meaning more photons reach the SiPM)
- Run 51260
- Run 71560
mean adc response and width ratio for different z bins 1, 5, 10, 15. Use run 41835 as reference to some 70k runs
- Run 81715
- Run 90660
- Run 111885
- Run 120848
- Run 51260
