Search found 56 matches

by Svilen
14 Dec 2017, 09:42
Forum: Spectrum
Topic: CS-137 Spectrum, new shield
Replies: 24
Views: 7689

Re: CS-137 Spectrum, new shield

Hi Steven, I made today some recording with Theremino and superimposed the graphs. It is easy to see that the peaks I have inside the castle are present also outside. Looks like it is not the lead, but more likely the environment or contamination on the surface of the detector. The second is maybe m...
by Svilen
13 Dec 2017, 11:52
Forum: Spectrum
Topic: CS-137 Spectrum, new shield
Replies: 24
Views: 7689

Re: CS-137 Spectrum, new shield

Just saw this video from Tom (antiprotons), doesn't it look like he have the same problem with his shielding here?
https://imgur.com/a/1fBTs

https://www.youtube.com/watch?v=gcNzV0jWf7I
by Svilen
12 Dec 2017, 20:22
Forum: Spectrum
Topic: CS-137 Spectrum, new shield
Replies: 24
Views: 7689

Re: CS-137 Spectrum, new shield

I know this about the K40 and also thought it may be it, but just too far away. The calibration I could only make using the 32Kev X-rays peak and the 662Kev peak from the Cs-137. I selected linear instead of slope, which is better to use in this case? I have also radium watch hands and thorium mantl...
by Svilen
12 Dec 2017, 19:00
Forum: Spectrum
Topic: CS-137 Spectrum, new shield
Replies: 24
Views: 7689

Re: CS-137 Spectrum, new shield

Just bad for the money wasted. Could be the copper maybe also..or could it be the epoxy? So these two peaks definitely shouldn't be there or? And how you find the background spectrum from the room, out of the shield? There are also some small peaks of activity between 700 and 1000KeV (approximately,...
by Svilen
12 Dec 2017, 09:28
Forum: Spectrum
Topic: CS-137 Spectrum, new shield
Replies: 24
Views: 7689

Re: CS-137 Spectrum, new shield

Hi Steve, Thank you very much for your comment. I read in the PRA's manual that the gain boost is for the weak signal of other detectors, but just was a bit unsure in the signal strength of mine. I have just to play a bit more with the software options and hardware to find the optimal settings. Have...
by Svilen
11 Dec 2017, 06:06
Forum: Spectrum
Topic: CS-137 Spectrum, new shield
Replies: 24
Views: 7689

CS-137 Spectrum, new shield

Hi All, After a while of inactivity due to lack of time for the hobby, I need your comments and advices again. In my last post I showed my first CS-137 spectrum with no shielding, now lets show the second attempt with what I lately constructed. This is maybe for the Shielding forum, but I post it he...
by Svilen
16 Apr 2017, 01:08
Forum: Spectrum
Topic: First CS-137 Spectrum
Replies: 2
Views: 1379

Re: First CS-137 Spectrum

Hi Steven, Thanks for your answer. The resolution is 7%, here is the picture again, with ROI selected and gaussian correlation turned on: Unfortunately, I don't have a source with known activity under 1000 Bq/kg, to test the limits of detection, but I hope with this detector I'm getting some good re...
by Svilen
15 Apr 2017, 17:58
Forum: Spectrum
Topic: First CS-137 Spectrum
Replies: 2
Views: 1379

First CS-137 Spectrum

Hi Steven and Others, This is what I got from a quite weak CS-137 source - an old spark gap tube. I thought, after all the years, there is not much of the CS left, but it was detectable (I also used a different detector than before). Can you please tell me how do you find this result? Is this perfor...
by Svilen
27 Mar 2017, 08:03
Forum: Detectors
Topic: Harshaw 8S8/2A-X
Replies: 18
Views: 8187

Re: Harshaw 8S8/2A-X

Thanks Steven, it is clear now. I'll change the divider resistors with metal foil ones, since I think these that I used are carbon resistors. I'll maybe get a better quality external sound card and will order some lead bars to improvise some fast and easy shielding just to test its effect. Lets see ...
by Svilen
25 Mar 2017, 22:53
Forum: Detectors
Topic: Harshaw 8S8/2A-X
Replies: 18
Views: 8187

Re: Harshaw 8S8/2A-X

Hi Steven,

Do you mean replacing both resistors with a single 1M trimmer using it's 3 connections, or two trimmers just to have two independent variable resistors instead of fixed ones?