Search found 22 matches

by valentin
07 Jan 2017, 21:29
Forum: Detectors
Topic: My spectrometry system
Replies: 7
Views: 3857

Re: My spectrometry system

Hi Alexander, it's some software I wrote on my own. It is just a prototype with most pulse detection parameters hardcoded to match my particular detector setup. Also, much functionality is only available through a command line interface. Last year's new year's resolution was to evolve this to a more...
by valentin
01 Oct 2016, 00:17
Forum: Shielding
Topic: Rolled lead as shielding
Replies: 9
Views: 4706

Re: Rolled lead as shielding

Hi Manuel,

there are lots of stores in Germany with all kind of lead in stock. At http://www.schrottmax.com/dresden-h1-Blei.html/ ( I am NOT affiliated in any way with their shop ) you can order both lead blocks and lead shot online. Expect some shipping cost due to the weight.

Valentin
by valentin
22 Aug 2016, 20:36
Forum: General discussion
Topic: Question about Cs137 decay
Replies: 2
Views: 2020

Re: Question about Cs137 decay

Hi Steven, Actually, you do not get any gammas from Cs137 >> Ba137m, which is a beta decay. The gammas are emitted when the excited Barium nucleus decays into it's ground state. As far as I understand, the Ba137m decays by either emmission of a 662 keV gamma ray or by internal conversion (which yiel...
by valentin
03 May 2016, 18:24
Forum: The lounge
Topic: New Look Forum
Replies: 1
Views: 2350

Re: New Look Forum

Hi Steven,

I like it, Tscherenkov radiation is beautiful :-)

Valentin
by valentin
01 Feb 2016, 05:42
Forum: Detectors
Topic: I need an advice regarding PMT, voltage divider etc.
Replies: 3
Views: 1711

Re: I need an advice regarding PMT, voltage divider etc.

Hi Vit, I do not have a data sheet either, but you can tell the pin layout by looking at the current resistor chain. By prepending a 10M resistor you would just reduce the voltage across the detector to about 30% of the voltage provided by your HV supply. So you have to replace the resistors in the ...
by valentin
01 Dec 2015, 20:02
Forum: Spectrum
Topic: Volcanic Eruptions Cause 40% Increase In Background Radiation Levels?
Replies: 5
Views: 3722

Re: Volcanic Eruptions Cause 40% Increase In Background Radiation Levels?

Hi Peter, in addition to effects on the geiger tube, you will often find elevated background radiation after heavy Rain due to the washout of Radon daughters from the atmosphere. The Radon concentration in the air also varies depending on meteorological conditions, see for example http://journals.am...
by valentin
24 Nov 2015, 21:17
Forum: Detectors
Topic: Making a scintillator
Replies: 22
Views: 9506

Re: Making a scintillator

Hi Yvan, In principle, non-metal enclosures work, I even saw home made probes made with tape or heat shrink tubing. Keep in mind that the enclosure must be lightproof. A thin PVC pipe may not be enough, even if it "looks" opaque. A metal enclosure connected to the GND provides an Equipotential aroun...
by valentin
18 Nov 2015, 21:00
Forum: Detectors
Topic: Making a scintillator
Replies: 22
Views: 9506

Re: Making a scintillator

Hi, the choice of scintillator depends on your requirements. Many plastic scintillators are unsuitable for spectoscopy, as only a small fraction of gammas will have their full energy converted into a photoelectron. However, if you just need count rate (like a geiger counter, but with a much higher d...
by valentin
16 Nov 2015, 19:15
Forum: Detectors
Topic: Making a scintillator
Replies: 22
Views: 9506

Re: Making a scintillator

Hi Yvan,

100.000cpm is pretty much. I would suggest testing your PMT without a crystal attached. If you still see these pulses, then something is wrong with your setup. For example, the voltage may be too high, causing a lot of random discharges inside the PMT.

Valentin
by valentin
17 Oct 2015, 21:13
Forum: Spectrum
Topic: Uranium without daughters
Replies: 3
Views: 2253

Re: Uranium without daughters

That is pretty cool. With uranium-ore, these peaks are mostly "burried below" all the scattered gammas from daughter decays.