XR-100CR Si-PIN X-Ray Detector + PRA

Scintillation crystals, PMTs, voltage dividers etc...
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pietkuip
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XR-100CR Si-PIN X-Ray Detector + PRA

Post by pietkuip » 10 Jun 2015, 01:11

I normally use the XR-100CR Si-PIN X-Ray Detector with their pocket MCA, but now I tried it with the sound input and PRA and Am-241.

To the right in the spectrum there is the 60 keV gamma. It is small because at this energy most photons pass straight through the silicon. At lower energy is a bunch of x-ray lines from the neptunium daughter atom. The strongest peak is at 14 keV. Resolution is very similar to when one uses the Amptek pocket MCA. At least on this computer - another one of the same make and model was much worse.

This might also work with a cheap pin diode at room temperature.
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xray_pra.jpg
xray_pra.jpg (115.84 KiB) Viewed 5630 times
Pieter Kuiper, Växjö (Sweden)
Course lab: 3 mCi neutron source; five 3" NaI(Tl) detectors, CdZnTe detector (Amptek); lead bricks, two GDM 20

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Steven Sesselmann
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Re: XR-100CR Si-PIN X-Ray Detector + PRA

Post by Steven Sesselmann » 12 Jun 2015, 14:12

Very nice resolution, this post inspired my to pull out an old project with a PIN diode detector from FirstSensor, but once again the project defeated me, I just can't seem to get any kind of signal from the detector, even when building the amplifier circuit according to the manufacturers diagram. Shall have to dedicate some more time to this another day.
Steven Sesselmann | Sydney | Australia | gammaspectacular.com | groundpotential.org | beejewel.com.au |

lodovico
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Re: XR-100CR Si-PIN X-Ray Detector + PRA

Post by lodovico » 17 Jun 2015, 23:53

Due to high resolution it would be nice to do some XRF with this type of sensor.
Normal range of XRF energy spans between 2keV and 50keV, so the sensor would be perfect.
Lodovico

pietkuip
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Re: XR-100CR Si-PIN X-Ray Detector + PRA

Post by pietkuip » 18 Jun 2015, 05:48

Am241AmptekPRA.png
Am241AmptekPRA.png (54.32 KiB) Viewed 5575 times
This is a comparison of PRA+soundcard and the Amptek PocketMCA. Most peaks are characteristic lines of neptunium, the daughter of americium, values from http://nucleardata.nuclear.lu.se/toi/nu ... iZA=950241. There are also strong lines of gold, because the americium was deposited in or under gold.

The difference in resolution is small. It affects the appearance of this complex spectrum most att the neptunium Lb1 and Lb2 peaks. I had to decrease the tolerance to resolve these peaks, which discarded about half of the pulses. If I kept all pulses, Lb2 was just a shoulder.

To get reasonable resolution from a PIN diode, it seems to be very important to avoid noise from capacitances (reading http://www.carroll-ramsey.com/detect.htm). For better values, one should then cool the diode (Amptek, Moxtek).
Pieter Kuiper, Växjö (Sweden)
Course lab: 3 mCi neutron source; five 3" NaI(Tl) detectors, CdZnTe detector (Amptek); lead bricks, two GDM 20

lodovico
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Re: XR-100CR Si-PIN X-Ray Detector + PRA

Post by lodovico » 18 Jun 2015, 17:10

I love these spectra .. I am a little bit envious of your Si-PIN detector ... :-)
Lodovico

pietkuip
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Re: XR-100CR Si-PIN X-Ray Detector + PRA

Post by pietkuip » 25 Jun 2015, 07:27

On http://www.sciencemadness.org/talk/view ... ?tid=28582, I came across this site: http://freshlab.org/detektor/?lang=eng; inexpensive ("less than 20 euros"), and amazing results. The Polish version seems to offer some more detail. Also, that spectrum is a bit less spectacular.

Polish presentation.
Pieter Kuiper, Växjö (Sweden)
Course lab: 3 mCi neutron source; five 3" NaI(Tl) detectors, CdZnTe detector (Amptek); lead bricks, two GDM 20

Paul McK
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Re: XR-100CR Si-PIN X-Ray Detector + PRA

Post by Paul McK » 09 Jul 2015, 00:11

sesselmann wrote:Very nice resolution, this post inspired my to pull out an old project with a PIN diode detector from FirstSensor, but once again the project defeated me, I just can't seem to get any kind of signal from the detector, even when building the amplifier circuit according to the manufacturers diagram. Shall have to dedicate some more time to this another day.
Steven

I also tried a X100-7 I have on a Radiationwatch type 5 PCB after reading these posts. It seems to be the same cct as the First Sensor appl note, the PCB has an aluminium shield around the front end cct and with it removed there is parasitic oscillation at 2.5MHz could this be your problem? I made a fiddly attachment of a 0.01uF cap direct to the Op Amp o/p which made the oscillation worse and had to really layer on the shielding, this worked and it has reasonably low noise level with a pulse peaking (upwards of 2V) at about 40usec and returning to zero in another 130usec with little undershoot. I ran this straight into the sound card but the results seem useless on Th, U and potassium. The count rate is about 1.5cps so it takes quite a while to get a pulse shape in PRA let alone a spectrum ref attached. The type 5 cct gives a detected pulse o/p via a comparator so I was able to monitor this on a CRO and verify the PRA pulses being registered were not noise it's easy to do as the count rate is so low.

The pulse viewer in Theremino seems to show a reasonable pulse with nothing too amiss I have attached a PRA pulse shot does the pulse look OK?

I can only think to try an Am source and get into the diode operating range of 100% absorption (vs 10% for the energies I was using) any ideas?
Attachments
Th spectrum 5.5k counts.jpg
Th spectrum 5.5k counts.jpg (201.24 KiB) Viewed 5442 times
PRA pulse.jpg
PRA pulse.jpg (8.96 KiB) Viewed 5442 times
Paul McKelliff
Adelaide/ South Australia

Homebrew 2"x 2" NaI(Tl) & smaller CsI(Tl) NaI(Tl) Scintillation detectors
GS1100 PRO & Asus U7 sound card
Homebrew 30kg 4 module lead castle

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Steven Sesselmann
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Re: XR-100CR Si-PIN X-Ray Detector + PRA

Post by Steven Sesselmann » 19 Jul 2015, 17:15

Paul,

I have put the X100 on the shelf for the moment after spending hours with little or no results. I too was able to get a spectrum similar to what you have above, but when I listen to the signal over the speakers it doesn't sound like the random clicks from a detector, it sounds more like noise, so I am not very confident. Also the noise increases when anything is brought close to the detector, radioactive or not. Obviously the signal to noise ratio is very low so as you say it really needs a very careful build with shielding in order to work, and I just don't have the time and patience to do it now, but will come back to it another day.
Steven Sesselmann | Sydney | Australia | gammaspectacular.com | groundpotential.org | beejewel.com.au |

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