SrI2(Eu) detectors

Scintillation crystals, PMTs, voltage dividers etc...
Rob Tayloe
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Re: SrI2(Eu) detectors

Post by Rob Tayloe » 08 Feb 2023, 00:30

Another thing that I should mention is the count times for the CsI and NaI detectors. They are of the same size, but for the CsI detector the count time was 11 hours; for the NaI only 30 minutes counting time was used. As I mentioned, it is a bit of "apples to oranges" comparison. I should go back and do more "fair" comparisons, e.g. same detector-to-source geometry, same counting time, etc.

RobertD
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Re: SrI2(Eu) detectors

Post by RobertD » 08 Feb 2023, 00:39

Thanks for the explanations, Rob. I might get one of these compact Capescint detector assemblies in the near future if all goes well.

As promised, here are some instructions to install the MCA web app on your Red Pitaya. Let me know if you have any questons.
Attachments
RP_MCA_install.pdf
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Robert

RobertD
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Re: SrI2(Eu) detectors

Post by RobertD » 08 Feb 2023, 00:50

With the Red Pitaya with the Windows downloadable MCA-PHA software the spectra obtained may be less than optimal due to the incomplete collection of the pulse from the SrI2(Eu) with SiPM. A while back, when I first obtained the Red Pitaya 125-14 unit I asked the CapeScint folks about this issue. More discussion is found within the thread linked below -

viewtopic.php?f=15&t=851&start=20
You might be able to improve the performance by changing sample rate and wait time value in the settings menu of the multicannel-analyzer app.
Robert

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Re: SrI2(Eu) detectors

Post by RobertD » 08 Feb 2023, 01:04

I just noticed that my pdf screwed up the important part of the instructions. So here they are again:

Code: Select all

ssh root@yourRedPitayas_Iocal_IP_address   (default password is root)
git clone https://github.com/pavel-demin/redpitaya-multichannelanalyser
export INSTALL_DIR=/opt/redpitaya
cd redpitaya-multichannelanalyser
make install
Robert

Rob Tayloe
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Re: SrI2(Eu) detectors

Post by Rob Tayloe » 08 Feb 2023, 01:22

RobertD wrote:
08 Feb 2023, 01:04
I just noticed that my pdf screwed up the important part of the instructions. So here they are again:

Code: Select all

ssh root@yourRedPitayas_Iocal_IP_address   (default password is root)
git clone https://github.com/pavel-demin/redpitaya-multichannelanalyser
export INSTALL_DIR=/opt/redpitaya
cd redpitaya-multichannelanalyser
make install
Thank you for the instructions. Do I need to install a compiler on the Red Pitaya? I likely do need to update the software as I am using that which was obtained a couple of years ago.

RobertD
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Re: SrI2(Eu) detectors

Post by RobertD » 08 Feb 2023, 02:12

No, the C compiler is already part of the OS.
Before updating the OS, you might as well give it a shot with your current one.
Good luck!
Robert

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Madmax
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Re: SrI2(Eu) detectors

Post by Madmax » 15 Feb 2023, 12:30

Hi all,
Do anybody know what's inside CapeSym's MCA and how it behaves when temperature changes and/or high count rates like 10000-30000 cps or higher?
Any information will be highly appreciated.
Regards!
Maxim, ATOM project, Sydney, Australia.

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Re: SrI2(Eu) detectors

Post by RobertD » 15 Feb 2023, 16:52

Hi Maxim,
All it says in the manual (downloadable from their website as part of the Windows software) that it is STM32 based. Regarding temperature changes the manual says:
Temperature stabilization automatically adjusts the high voltage bias on the SiPM array to maintain a consistent relationship between the energy deposited in the detector and the size of the pulse integral
For tuning the temp compensation, you basically put the chilled probe next to a known source and as the probe warms up the software calculates the calibration curve which can be stored in the NVM.
Maximum achievable count rate varies with the scintillator material, I assume this is due to different decay times.
There is also a feature called pulse pileup rejection which improves quality at higher count rates.
Robert

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MartinM
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Re: SrI2(Eu) detectors

Post by MartinM » 26 Feb 2023, 09:42

Just got a SC-MacroPixel-MCA with a declared resolution of 3.15%, so I wanted to share some experience.
The device is small, compact and looks great. A very nice job given how much is integrated inside. Just plug in the cable, and start the CapeMCA software. Simple and stable.
The software is quite advanced and requires a bit learning but the documentation is well written in detail, so it's not a big issue. What I liked is that you have full control of all parameters which can also be stored in the built-in EPROM. What surprised me is that the MCA has 4096 channels (most NaI/CsI have 1024).
The device came without calibration so I have spent many hours setting this up. The Temperature calibration (using the Automatic calibration) seemed easy but it requires constant watching of parameters to warm-up the probe slow enough so that for each 0.5 C step the device has enough time to sample the 662 peak, but not very slow so you won't spend the entire day with the procedure. At the beginning it's best to freeze a piece of metal as a thermal inertia block and then then keep it in contact with the probe. I started with 2 blocks (one below and another on top of it) as initially the devices warms up very quickly. But later when temperature gets closer to room temperature, the process slows down so first I removed the top block, then the bottom one and closer to 30 C it needs to be put close to a heat source (but heat up carefully).
So I just finished the TS calibration and going to make some real measurements. Will update later...

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Madmax
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Re: SrI2(Eu) detectors

Post by Madmax » 26 Feb 2023, 23:29

Thanks, Martin!
Will wait for updates.
It's very interesting how the MCA will behave in real life after time and under high loads.
Looking at pictures of covered with compound PCB exposed on eBay I assume that MCA should be very simple, but it's not possible to see the parts.
Do you have any X-ray setup to take X-ray picture of this MCA?
Have a nice day!

Maxim
Regards!
Maxim, ATOM project, Sydney, Australia.

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