Search found 826 matches

by Sesselmann
08 May 2021, 15:58
Forum: Detectors
Topic: First attempt at building an alpha beta detector
Replies: 12
Views: 287

Re: First attempt at building an alpha beta detector

Lukas,

How do I discriminate between alpha and beta when the source is placed inside the chamber ?

Steven
by Sesselmann
07 May 2021, 13:03
Forum: Detectors
Topic: First attempt at building an alpha beta detector
Replies: 12
Views: 287

Re: First attempt at building an alpha beta detector

Hi guys, Just a quick update on this proportional counter experiment. I modified a new GS-USB-PRO with a higher value 10M load resistor and a 50pF coupling cap, this works much better for high impedance proportional counters including Neutron counters. Based on Lukas advise I placed some aluminium f...
by Sesselmann
06 May 2021, 20:14
Forum: Introductions >> Start Here !
Topic: Hello from sunny California
Replies: 1
Views: 32

Re: Hello from sunny California

Hi Felicia,

Welcome to the forum, your research sounds interesting, would love to learn more about detecting anti neutrino's, hope you can share some of that with us.

See you around..

Steven
by Sesselmann
04 May 2021, 10:12
Forum: Detectors
Topic: high count rate spectrometry
Replies: 1
Views: 64

Re: high count rate spectrometry

Jonathan, High count rates are the enemy of sound card spectrometry, it is much better suited to measuring contamination in mushrooms :) Your estimates are too high, as you have not allowed for deadtime, with pulses of 100 µs your counting plateu is more likely to be 3000 cps. Generally the minimum ...
by Sesselmann
03 May 2021, 10:36
Forum: Detectors
Topic: Building and testing a sealed proportional detector
Replies: 2
Views: 59

Re: Building and testing a sealed proportional detector

Lukas, Thanks for posting this detailed description of your build. Allthough the procedure is more or less straight forward I think the use of high vacuum apparatus will exclude most tinkerers. Even myself who has a good vacuum system with turbo pump would have to rebuild it at some considerable cos...
by Sesselmann
01 May 2021, 14:30
Forum: Detectors
Topic: First attempt at building an alpha beta detector
Replies: 12
Views: 287

Re: First attempt at building an alpha beta detector

Cool, I really like that hack using PCB to close the ends of the tube. I'm not sure if I want to put that much effort into making a GM tube, but if we could make a proportional tube the same way, it would be worth the effort. But as you said above, I would need quite an elaborate vacuum system to ev...
by Sesselmann
30 Apr 2021, 20:08
Forum: Detectors
Topic: First attempt at building an alpha beta detector
Replies: 12
Views: 287

Re: First attempt at building an alpha beta detector

That all makes a lot of sense, and I already figured one would need good vacuum, I have all the vacuum gear but it's not worth setting up for one experiment. Not sure how to get a good ceramic to metal seal for the feedthrough, might have to buy these parts and braze, or do you think JB Weld glue wo...
by Sesselmann
30 Apr 2021, 09:55
Forum: Detectors
Topic: First attempt at building an alpha beta detector
Replies: 12
Views: 287

Re: First attempt at building an alpha beta detector

But IMO there are a few issues with your design. The chamber floor has to be conductive, both to shape the field, and to act as an eMI shield. Thanks for reply. Yes I agree, that makes perfect sense, I must have been blinded by the fact that plastic machining was so much easier :) I can make a roun...
by Sesselmann
28 Apr 2021, 19:10
Forum: Detectors
Topic: First attempt at building an alpha beta detector
Replies: 12
Views: 287

First attempt at building an alpha beta detector

Hi Guys, Inspired by the project Lukas did, I attempted this myself with mixed success. My design is similar to Lucas, but with a few differences. I machined the base from 130 mm HDPE and fitted a 1/8" Hose barb with a channel through to the chamber, I also drilled an outlet for the gas on the oppos...
by Sesselmann
20 Apr 2021, 09:29
Forum: Detectors
Topic: Calibration of Ludlum 44-3 with 241Am failing
Replies: 4
Views: 412

Re: Calibration of Ludlum 44-3 with 241Am failing

Dave, The count rate plateau is a test of the PMT and that looks normal. Typical bias voltages are usually in the 650 to 750 range and that agrees well with your experiment. My guess is that your thin 1mm crystral is damaged, most likely the encapsulation has failed and the crystal has become wet. I...