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  proton-capture on 118Te  Not logged in ELOG logo
Message ID: 273     Entry time: Wed Apr 8 20:06:10 2020
Author: Laszlo 
Category: Calibration 
Subject: Counts in the K-REC peaks 
Year:  
3 datasets were investigated:
-124Xe with Scraper (2. Xray calibration parameters needed)
-124Xe without Scraper (2. Xray calibration parameters needed)
-118Te with Scraper (1. Xray calibration parameters needed)

I looked all the 35°, 90° and 145° detector spectra:
-For both Xe measurements all 3 detector signal can be evaluated
-For Te beam one can see only in the 145° detector spectra the Kalpha and K-REC peaks (with high uncertainty). For the 35° probably the detector was simply not sensitive enough for such low beam intensities. For the 90° case, I am much surprised, the peaks supposed to be there the most prominent of all. In the spectra, I maybe can recognize a peak at ~27,8keV, but this is even in best case only the Kalpha peak. At the range of the expected K-REC (~40keV), there is a bit of increase in the background overlying the peak. This background increase is also in the background spectra. Also probably this twisted cables issue between 90° and 145° didn't help much. I think anyhow, that maybe this must have some noise related origin. I can remember that the cables (despite all of our and Uwe's tries) were not well grounded, the noise level was kind of floating.

In general, I would also remark that we can see some peaks >60keV in the background, but these luckily don't disturb us.


To evaluate the Xray spectra I used the following algorithm:
1, for each type of beams I used the list of event numbers in the next entry (to exclude "bad" events)
To get the Kalpha and K-REC and other peaks I used the condition trigger==1 (jet ON)
To get the background spectra, I used trigger==2 (Jet OFF). The background spectra is only used to see that there is no underlying peak structure below K-REC. To subtract count, the background histo was NOT in use.
2, While using a well-suiting number of bins, I plot the JetON and JetOFF histos.
By eye I choose the range of the K-REC peak and the range for the background fit on the JetON histo. Ofc range_bckgnd > range_peak.
Simultaneously, I check on the JetOFF histo that both, in the fit-range and in the peak-range, there should not be any peak structure visible.
3, For the fit-range in JetON histo, excluding the peak-range, I fit a linear function, m*x+b. For each bin in the fit-range I subtract m*bin_center+b value from the bin content. After the subtraction I check if I got spectra looking like a single peak sitting on a zero
line.
4, To get the K-REC counts, I sum together all the bin values for each bin of the subtracted histo within the peak-range. For the error calculation, I use Gaussian error prop. The uncertainty of the JetON histo counts = sqrt(counts). Also for the subtraction I make the
error like delta(m*bin_center+b)= sqrt(m*bin_center+b) instead using the uncertainty of the fit parameters. This second one wont make much sense, since the slope of the linear fit is usually close to 0 --> the errors grow unrealistically big.


Based on the algorithm above I got the following counts:
-124Xe with Scraper:
35°: 174 +/- 15
90°: 21299 +/- 150
145°: 2104 +/- 52

-124Xe without Scraper:
35°: 65 +/- 9
90°: 7792 +/- 91
145°: 728 +/- 31

-118Te_part1 with Scraper:
35°: -
90°: 427 +/- 40
145°: -

-118Te_part2 with Scraper:
35°: -
90°: 741 +/- 48
145°: -

-124Xe_lowRate with Scraper:
35°: -
90°: 2121 +/- 52
145°: -
Attachment 1: 124Xe_wScraper_full_spectra_labels_thick.png  94 kB  Uploaded Wed Apr 8 23:59:20 2020  | Show | Show all
Attachment 2: 124Xe_wScraper_90_backgnd.png  30 kB  Uploaded Tue May 5 00:46:20 2020  | Show | Show all
Attachment 3: KREC-pics.zip  324 kB  Uploaded Tue May 5 00:46:26 2020
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