SrI2(Eu) detectors

Scintillation crystals, PMTs, voltage dividers etc...
Rob Tayloe
Posts: 35
Joined: 10 Nov 2020, 12:00
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Re: SrI2(Eu) detectors

Post by Rob Tayloe » 12 May 2021, 09:39

The folks at CapeScint that made the small SrI2(Eu) detector discussed earlier now have a small USB MCA attached to the 14x14x25 mm detector assembly. I have not seen or used this MCA, however more information may be found in the links below -

https://capescint.com/product/scintilla ... pixel-mca/

https://capescint.com/wp-content/upload ... asheet.pdf

The CapeScint contact is -

Ivan V. Khodyuk
CapeSym, Inc.
508-653-7100 x214
www.capescint.com

Rob Tayloe
Posts: 35
Joined: 10 Nov 2020, 12:00
Contact:

Re: SrI2(Eu) detectors

Post by Rob Tayloe » 15 Jun 2021, 01:22

In a previous post I mentioned that CapeSym had come out with a small ScintiClear Strontium Iodide detector (14mm x 14mm x 25mm) that was integrated with a small USB MCA. A link was given for this device.

I obtained one of these integrated MCA ScintiClear detectors. CapeSym has deveoped software that works on a PC to drive the MCA and display and save acquired data. I will share my thoughts and some data from use of this detector and software.

I was also loaned an experimental ScintiClear MCA unit with a smaller detector. The smaller detector was 14mm x 14mm x 6mm and is intended for use in detection of lower energy gammas and x-rays. I believe that this smaller detector has a thin (0.5mm) Be window on the detector end. In an earlier blog post Max Fomitchev-Zamilov (of the Maximus Energy website) posted about an even smaller ScintiClear detector (2mm thick) made for low energy gamma and x-ray detector. He also posted about the 25mm thick ScintiClear detector. Links are given below to his blog postings -
https://maximus.energy/index.php/2020/1 ... -detector/
https://maximus.energy/index.php/2020/1 ... -detector/

Max used his own software with a PicoScope unit to measure various gamma spectra. Earlier in this thread I have discussed my use of the ScintiClear Strontium Iodide detector with a PicoScope 4262 and Max's software. In this and subsequent postings I will show results from the two ScintiClear MCA units and a ScintiClear detector with Max's software.

Following are photos of the two ScintiClear MCA units. The smaller experimental detector has a black shrink tube cover whereas the larger unit has the silver-colored metal cover. The USB end has a single LED to indicated that the detector & MCA is powered -
DSC03894.JPG
DSC03895.JPG
DSC03896.JPG
DSC03897.JPG

Rob Tayloe
Posts: 35
Joined: 10 Nov 2020, 12:00
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Re: SrI2(Eu) detectors

Post by Rob Tayloe » 15 Jun 2021, 01:32

One of the first things that I did after verification that the ScintiClear detector & MCA units were functioning was generate energy calibration curves. Shown below is the tabular data acquired for the three detectors followed by energy calibration curves along with least squares polynomial fitted functions for each curve. These functions are used to map the channel (or bin) spectral data to an energy spectra.
energy-cal-SC-data.jpg
energy-cal-SC-data.jpg (88.46 KiB) Viewed 161 times
energy-cal-SC-curves.jpg

Rob Tayloe
Posts: 35
Joined: 10 Nov 2020, 12:00
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Re: SrI2(Eu) detectors

Post by Rob Tayloe » 15 Jun 2021, 01:46

The smaller detector is limited in the energy of the gamma ray that is acquired. The 662 keV photopeak from Cs-137 (Ba-137m) is about the upper range that can be obtained.

The two ScintiClear detectors having the 25mm thickness have very similar calibration curves. One might wonder why the 1408 keV photopeak was not recorded for the ScintiClear MCA unit. The reason is because, at present the software displaying the spectrum can only display the data linearly; there is not log display ability for the Y-axis. It is difficult to view the 1408 Eu-152 peak without a log display. Max's software will allow the spectrum to be displayed in either a linear or log manner.

Following are images of the displayed spectrum for Cs-137 for each detector. It should be noted that the FWHM resolution values given have not yet been mapped from channel space to energy space. -
sc-14x6c-mca4-cs137-001.jpg
sc-mp-mca-010617-cs137-001.jpg
sc-mp-mca-010617-cs137-001.jpg (89.26 KiB) Viewed 161 times
sri-a-cs137-001.jpg

Rob Tayloe
Posts: 35
Joined: 10 Nov 2020, 12:00
Contact:

Re: SrI2(Eu) detectors

Post by Rob Tayloe » 15 Jun 2021, 01:52

The following image shows the three ScintiClear detectors acquiring data from a small thorium sample. This configuration was used for the subsequent measurements made. This is an unshielded measurement. -
DSC03905.JPG

Rob Tayloe
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Joined: 10 Nov 2020, 12:00
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Re: SrI2(Eu) detectors

Post by Rob Tayloe » 22 Jun 2021, 11:10

I have reconsidered the energy calibration fit shown above for the three ScintiClear detectors. The plot below uses a second order polynomial and gives a very good correlation to the data. Use of more data values (i.e., isotope photo peaks) would no doubt yield an even better energy calibration.
I am also uploading a compressed (7zip) version of my spreadsheet containing the energy calibration data, plot and least squares fit, and data from a number of measurements. Plots from those measurements are also shown below.
SC SrI Energy Cal2105.7z
(1.02 MiB) Downloaded 10 times
E-cal.jpg
radium.jpg
U metal.jpg
monazite.jpg
ThO2.jpg
UO2.jpg
Ba133.jpg
Eu152.jpg
U ore.jpg
thorite.jpg

Rob Tayloe
Posts: 35
Joined: 10 Nov 2020, 12:00
Contact:

Re: SrI2(Eu) detectors

Post by Rob Tayloe » 04 Jul 2021, 04:56

Seems as though some stuff was lost in the hack. I am reposting those images and more from the prior post -

7zip version of spreadsheet with calibration data and plots and various spectra data and plots -
SC SrI Energy Cal2105.7z
(1.02 MiB) Downloaded 1 time
Measured spectra with three indicated SrI2(Eu) detectors -
Ba133.jpg
Eu152.jpg
monazite.jpg
radium.jpg
ThO2.jpg
thorite.jpg
U metal.jpg
U ore.jpg
UO2.jpg
Attachments
E-cal.jpg

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