Search found 758 matches

by Steven Sesselmann
04 Jul 2020, 21:38
Forum: Detectors
Topic: Liquid Scintillators
Replies: 2
Views: 15

Re: Liquid Scintillators

Lukas, Those look like an interesting find. Did you test them with a PMT and if so did they give any spectrum? Here is a reference to a comprehensive list of scintillation materials, maybe the mystery liquids are on there; http://scintillator.lbl.gov It would be interesting to make some liquid scint...
by Steven Sesselmann
04 Jul 2020, 08:58
Forum: Introductions >> Start Here !
Topic: Greetings from Munich
Replies: 4
Views: 20

Re: Greetings from Munich

Hello Lucas, Welcome to the forum. Sorry I forgot to tell you that one of our moderators manually approve the first three posts by new users, so it can take a bit of time before they appear. Sounds like you are well equipped and on the road to do some interesting neutron activation experiments ;) I ...
by Steven Sesselmann
29 Jun 2020, 08:29
Forum: Detector drivers
Topic: GS-1100-Pro only outputting half voltage
Replies: 1
Views: 28

Re: GS-1100-Pro only outputting half voltage

Quaid, What you are seeing is perfectly normal. The voltage display on the GS measures the voltage on the high end of the load resistor, therefore it technically displays the correct voltage for infinite impedance, but when you connect a standard multimeter with ~2M impedance, the voltage will read ...
by Steven Sesselmann
28 Jun 2020, 17:52
Forum: Introductions >> Start Here !
Topic: Heya everyone
Replies: 2
Views: 42

Re: Heya everyone

Hi Quaid, Anyone with a humble collection of radiation detectors is going to be welcome here :) Sorry you had to go through hoops to sign up here, but we had ongoing issues with spammers, and the text message seems to have deterred them. Enjoy the forum and exchange your experiences with the other m...
by Steven Sesselmann
28 Jun 2020, 14:42
Forum: Detectors
Topic: Questions about Voltage Divider PMT bases
Replies: 6
Views: 92

Re: Questions about Voltage Divider PMT bases

Andrey, I am not an expert on this subject, but there is plenty of information about resistor noise on the web. http://www.resistorguide.com I also found this calculator for Johnson noise here: https://www.daycounter.com/Calculators/Thermal-Noise-Calculator.phtml According to that calculator a 12 M ...
by Steven Sesselmann
27 Jun 2020, 21:32
Forum: Detectors
Topic: Questions about Voltage Divider PMT bases
Replies: 6
Views: 92

Re: Questions about Voltage Divider PMT bases

Mike, Just one additional note on resistors. Use a quality metal film resistor and not just any low grade carbon type, the reason is resistor thermal noise or "Johnson noise". Long version here: https://en.wikipedia.org/wiki/Johnson–Nyquist_noise In a laboratory where you have a mains powered NIM po...
by Steven Sesselmann
23 Jun 2020, 14:41
Forum: General discussion
Topic: Instrument cables.
Replies: 6
Views: 221

Re: Instrument cables.

James,

I can make up quality 50 ohm coaxial cables for you, just send me a PM and let me know how many and whet type you need and I shall give you a quote.

Steven
by Steven Sesselmann
12 Jun 2020, 11:15
Forum: General discussion
Topic: Mu-Metal.
Replies: 6
Views: 231

Re: Mu-Metal.

James, Good question.. Frankly I have never read any studies on the effect of magnetic shielding. I have pulled apart many detectors and some have thicker 0.6-1.0 mm shielding and others have a thinner 0.1 mm. I use Ultraperm 80 by 3M in my detectors, it's around 0.004" and wrap it around the PMT. I...
by Steven Sesselmann
04 Jun 2020, 13:12
Forum: Detectors
Topic: Pulse height shift with pulse rate?
Replies: 4
Views: 236

Re: Pulse height shift with pulse rate?

Mike, Interesting observation, I have never noticed it, are you seeing the same thing in PRA? How much difference in pulse rate are we talking about? The limitation of sound card spectrometry seems to be around 2000 - 2500 cps., so it's generally a good idea to stay below this. In any case it would ...
by Steven Sesselmann
30 May 2020, 20:27
Forum: Detector drivers
Topic: Gamma spectacular + Red Pitaya = Nuclear Dragon fruit?
Replies: 5
Views: 573

Re: Gamma spectacular + Red Pitaya = Nuclear Dragon fruit?

Conor Whyte wrote:
18 May 2020, 17:42

The interactive html document is a nice touch. -- I can't upload it here.
Would there be a way of showcasing interactive spectra from interspec on the page?
Conor,

Can you send me the HTML page, maybe I can drop it on the server.

Steven