Search found 943 matches

by Sesselmann
15 Mar 2022, 17:16
Forum: Spectrum
Topic: What is this nuclides in wild mushroom from europe?
Replies: 15
Views: 481

Re: What is this nuclides in wild mushroom from europe?

ChrisqMalibu wrote:
15 Mar 2022, 00:44
Here is the spectrum with peak @ ~ 400 keV (using Sum Quantity in PRA)
So which isotope is creating the peak at 400 keV ?

What detector are you using here?

Have you considered using background subtraction?

Steven
by Sesselmann
14 Mar 2022, 12:30
Forum: Detectors
Topic: Sensitivity of Scionix Holland Gamma Scintillation Detector NaI(Tl) 38mm probe & others
Replies: 2
Views: 209

Re: Sensitivity of Scionix Holland Gamma Scintillation Detector NaI(Tl) 38mm probe & others

Chris, The sensitivity or efficiency of an NaI(Tl) detector is a function of the crystal size and gamma energy, so it depends very little on what instrument you use to count the pulses. Typically an encapsulated 1.5" NaI crystal will have an absorption efficiency of 60% at 662 keV., this effici...
by Sesselmann
13 Mar 2022, 10:12
Forum: Shielding
Topic: Shielding Build
Replies: 2
Views: 255

Re: Shielding Build

programmer1200 (please sign posts with your real name, PVC is an easy and cheap material to work with. Your design resembles the way I used to make my PVC shields, although I am a bit confused about where you intend placing the detector. I recently changed my design to a straight cylinder, with a 3D...
by Sesselmann
13 Mar 2022, 10:05
Forum: Introductions >> Start Here !
Topic: Hello from Malibu, California
Replies: 2
Views: 167

Re: Hello from Malibu, California

Chris,

Welcome to the forum and thanks for the introduction.

Make sure you read a bunch of posts in the Shielding forum before you start constructing a shield, it's always good to see what others have done, that way you can pick the best ideas.

Look forward to reading your posts.

Steven
by Sesselmann
09 Mar 2022, 10:38
Forum: Introductions >> Start Here !
Topic: Hello from Missouri
Replies: 1
Views: 179

Re: Hello from Missouri

Zachary,

Welcome to the group, I see why you are interested in gamma spectrometery and I am sure you will find it interesting, there is a lot more going on in a bucket of dirt than most people realise.

Feel free to discuss your lead shield ond other findings in the appropriate forums.

Steven
by Sesselmann
08 Mar 2022, 13:03
Forum: Detectors
Topic: gamma spectrometer signal
Replies: 11
Views: 2158

Re: gamma spectrometer signal

Pawel, I opened your file in Audacity, I can see you have lot's of small pulses on a relatively noisy baseline noise < 0.5 arb.u, so the noise is not your main problem, although great if you can filter it. The spectrum shows most of the pulses piled up on 5 arb.u., I'm not sure, but maybe you just d...
by Sesselmann
04 Mar 2022, 11:41
Forum: Detectors
Topic: 2*pi vs 4*pi
Replies: 7
Views: 292

Re: 2*pi vs 4*pi

Steven, I think you mixed something up here. The bigger the source is compared to your detector the lower the overall efficiency is, unless you insert your detector into the source. Think of the source as a light bulb and your detector as something blocking the light, eg. your hand. If the light bu...
by Sesselmann
03 Mar 2022, 10:43
Forum: Detectors
Topic: 2*pi vs 4*pi
Replies: 7
Views: 292

Re: 2*pi vs 4*pi

Greg, Good question...., as you already understand, a point source will radiate in all directions so if your detector is placed at a distance r the energy reaching the probe is proportional to 1/4πr^2 If however you have a large source like a big rock and you place your detector in contact with the ...
by Sesselmann
02 Mar 2022, 12:13
Forum: Detectors
Topic: gamma spectrometer signal
Replies: 11
Views: 2158

Re: gamma spectrometer signal

Pawel, I have no experience with CdWO4 scintillator, so I don't know what resolution to expect. It does seem very strange that there is no information in your pulse height histogram. If you can measure pulses on your scope and you are sure you are recording the correct channel then there is no reaso...
by Sesselmann
01 Mar 2022, 17:11
Forum: Software
Topic: Help setting up PRA
Replies: 6
Views: 286

Re: Help setting up PRA

Trevor, It looks like your gain is way too low, you need to boost the voltage and up the gain. You have multiple adjustments which all increase pulse height. 1) Bias voltage 2) Preamplifier gain 3) Pulse shape 4) Boost gain The optimum gain is when the K40 peak at 1460 appears around 50 arb.u (middl...