Hi from Pieter at Linnaeus University

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pietkuip
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Hi from Pieter at Linnaeus University

Post by pietkuip » 06 May 2015, 08:20

I am very impressed by all the enthusiasts here. I also like playing with nuclear stuff, but in my case my employer is paying for my hobby: I am taking care of the course lab at the university. We had a bunch of NaI(Tl) scintillation detectors, lots of lead, a small neutron source with 3 mCi radium, etcetera. I am now getting rid of the classic MCA hardware that was dependent on old DOS computers and replacing it with soundcard software and GammaSpectacular drivers. But we also bought one Canberra Osprey, as a kind of benchmark.

I am into this hobby periodically, when students are having courses in nuclear physics. Right now I would like to explore with them the possibilities of doing coincidence experiments using the stereo input.

Another project is to develop simple counting experiments that students can access online using a web browser.
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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Sesselmann
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Re: Hi from Pieter at Linnaeus University

Post by Sesselmann » 06 May 2015, 11:30

Pieter,

Thanks for the intro.

I think you will find spectrometry with PRA to be an excellent tool for teaching. PRA was developed by Marek Dolleiser, who is the technical expert in the Year 3 physics lab at Sydney University. They have built many standard experiments using the software, including some that are not so obvious, like measuring cosmic rays. If you like I can probably find the instructions for some of these experiments.

Would be interesting to see how the GS and PRA measures up against the Canberra Osprey.

Coincidence or anticoincidence detection is easy with PRA, with two detectors you will be able to see annihilation peaks otherwise not possible. I have been able to detect the 511 peak above normal backgeround using no source at all.

If any students are interested in developing their own setup, I offer a flat $50 student discount on all GS drivers.

Steven

pietkuip
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Re: Hi from Pieter at Linnaeus University

Post by pietkuip » 06 May 2015, 16:28

Hi Steven,
I did a coincidence measurement with a Na-22 source, using PRA and two simple passive low-pass detectors. The result was very clear, all the background disappears, and it should be even better withe the GS drivers that I ordered. We also have a plastic scintillator, with which I intend to look at the coincidence between the Compton signal and the scattered gamma. And we will do the entanglement experiment: http://blogs.scientificamerican.com/cri ... rt-1-of-2/.

But I am wondering about that 511 keV peak without a source. Where are those positrons coming from? Is that due to pair production? Inside one of the scintillator crystals?
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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Sesselmann
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Re: Hi from Pieter at Linnaeus University

Post by Sesselmann » 06 May 2015, 17:25

pietkuip wrote: But I am wondering about that 511 keV peak without a source. Where are those positrons coming from? Is that due to pair production? Inside one of the scintillator crystals?
As I recall I had some lead between the detectors, and I assume the odd high energy gamma and cosmic ray might be responsible for pair production in the lead or in the detector itself. Allthough the peak was not obvious from the bins, the gaussian peak in PRA revealed it quite nicely at 511 keV.

Here is a link to a post on the old forum with Na22.

http://www.gammaspectacular.com/index.p ... &path=1175

Steven

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brehwens
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Re: Hi from Pieter at Linnaeus University

Post by brehwens » 06 May 2015, 17:36

Hi Pieter!

Nice to have you here, welcome! Especially nice that you are in Sweden!

What is your position in Växjö, are you a postdoc/lecturer/researcher?

/Karl
Karl Brehwens
Eskilstuna, Sweden.

Setup: 5 cm lead castle, 2mm copper lining. Gamma Spectacular Pro 2002, Sound Blaster Live! 5.1,
Primary detector: Scionix refurbished 2x2" NaI(Tl) well detector, 7.5% @ 662 keV

pietkuip
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Re: Hi from Pieter at Linnaeus University

Post by pietkuip » 06 May 2015, 21:55

@Steven: Ah, a piece of high-Z material between the detectors. That will be a nice teaching idea. And then students can try to find out the cause.

@Karl: I am a lecturer here in Växjö. My research background is in x-ray spectroscopy of solids, often using synchrotrons.
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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