Search found 158 matches

by Peter Schmelcher
Tue Dec 31, 2019 9:56 am
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: Amptek Digital Pulse Processor
Replies: 13
Views: 1208

Re: Amptek Digital Pulse Processor

The attached file is for a different rev of the board PC5 Power Supply User’s Manual Rev. A0 The HV feedback circuit uses a resistor divider which could be changed for a different bias voltage range. One would need to know the HV capacitor ratings or that all model variations use the same HV capacit...
by Peter Schmelcher
Mon Dec 30, 2019 10:54 pm
Forum: Fusor Construction & Operation (& FAQs)
Topic: Making Large Vacuum Chambers
Replies: 10
Views: 737

Re: Making Large Vacuum Chambers

I read someplace that cast aluminum is porous and outgasses so it is not good for high vacuum service. I see 300mm diameter 304 stainless garden spheres sell for under $30 on ebay, for example item # 202737785286 or # 153647487022 This is china and who knows the quality or the wall thickness you wil...
by Peter Schmelcher
Thu Nov 28, 2019 9:12 am
Forum: Fusor Construction & Operation (& FAQs)
Topic: Fusor construction questions
Replies: 27
Views: 1979

Re: Fusor construction questions

You might consider getting a gas dryer that could also double as a reservoir to isolate the cell. Make the gas in a batch and then later run and adjust the fusor and don't think about the gas generation. ebay item number 150382481448 (Supelco # 20619 Molecular Sieve Water Vapor Trap 200 cc).
-Peter
by Peter Schmelcher
Sat Aug 31, 2019 6:11 pm
Forum: FAQs: Neutron - Radiation Detection
Topic: FAQ - Neutron Transport Simulation, Detector Calibration, and Shielding
Replies: 10
Views: 4100

Re: FAQ - Neutron Transport Simulation, Detector Calibration, and Shielding

Nice work!

Another arrow in your quiver could be Cosmic ray generated neutrons. For initial testing, does my detector setup work, it’s a no brainier. For calibration it remains an unanswered question.

Previous post with attached papers.
viewtopic.php?t=11307

-Peter
by Peter Schmelcher
Tue Mar 12, 2019 6:38 pm
Forum: Fusor Construction & Operation (& FAQs)
Topic: Vaccum Leak Testing / Technique and Power Supply Question
Replies: 18
Views: 8694

Re: Vaccum Leak Testing / Technique and Power Supply Question

I believe the gurgling sound in the video is cavitation in the oil which is normal but only when the gas ballast is open or if you have a large leak. The oil reservoir screw cap probably has an o ring and should be closed when you are trouble shooting the vacuum pump. https://vacaero.com/information...
by Peter Schmelcher
Wed Feb 20, 2019 8:20 pm
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: SNM-11/СНМ-11 Tube - Again ...
Replies: 12
Views: 6658

Re: SNM-11/СНМ-11 Tube - Again ...

I would guess all these Russian tubes were originally intended for Chernobyl. They got stuck in storage for 30 years before finally being considered surplus junk and we got them cheap. Lukas I agree Geiger mode operation seems odd but who knows what was intended 30 years ago. If I was asked to desig...
by Peter Schmelcher
Wed Feb 20, 2019 1:31 am
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: SNM-11/СНМ-11 Tube - Again ...
Replies: 12
Views: 6658

Re: SNM-11/СНМ-11 Tube - Again ...

Increasing the bias voltage increases the gain of the tube. This change is not linear. At some higher bias voltage the atoms start to behave more like a ring of dominos, knock one over (ionize one atom) and they all fall down (which is Giger operation and I do not use the tube at that voltage). Yes,...
by Peter Schmelcher
Tue Feb 19, 2019 9:06 am
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: SNM-11/СНМ-11 Tube - Again ...
Replies: 12
Views: 6658

Re: SNM-11/СНМ-11 Tube - Again ...

I did lots of work many years ago with various Russian tubes. I knew a Russian Physics and he graciously translated a detector data sheet for me. The SNM11 / CHM11 tube has a maximum do not exceed voltage of 1600V. The recommended operating voltage is 700V and when detecting thermal neutrons the eff...
by Peter Schmelcher
Thu Jan 10, 2019 11:25 pm
Forum: Fusion --- Past, Present, and Future
Topic: Wendelstein 7-X has successfully finished its second major experimental run
Replies: 27
Views: 20742

Re: Wendelstein 7-X has successfully finished its second major experimental run

Hydrogen isotopes can now be separated from regular hydrogen using a membrane. I can’t remember the original research article read sometime in the last two years but it was a notable American university. I was amazed that a Nano technology membrane could exploit the very subtle atomic differences. h...
by Peter Schmelcher
Fri May 18, 2018 9:17 pm
Forum: Other Forms of Fusion - Theory, Construction, Discussion, URLs
Topic: lab electromagnet from scratch
Replies: 61
Views: 41549

Re: lab electromagnet from scratch

I believe you should split the electromagnetic, half around the top and half around the bottom. This should change the magnetic circuit potential in the support arms to zero opposite the air gap, the reduced coil diameter requires less wire so you will get more amp turns from your spool. My fading m...