Search found 1652 matches

by Dennis P Brown
Wed Feb 20, 2019 7:23 am
Forum: New User Chat Area
Topic: Neutron Attenuation Discrepency
Replies: 4
Views: 185

Re: Neutron Attenuation Discrepency

No one here can tell you about an unknown computer program used to correct for varying cross-section of neutrons depending on energy. Since your own people did, please consult them about conversion factors used. We have just discussed this very point/problem about counts from a detector and trying t...
by Dennis P Brown
Tue Feb 19, 2019 9:24 pm
Forum: New User Chat Area
Topic: Neutron Attenuation Discrepency
Replies: 4
Views: 185

Re: Neutron Attenuation Discrepency

While this is a complex subject, a few quick points. Neutrons do not attenuate like simple x-rays or even alpha particles. They are not absorbed but only scattered (unless you have added an neutron absorber to the shielding). As such, there are many neutrons 'floating around" so to speak as thermali...
by Dennis P Brown
Sun Feb 17, 2019 4:38 pm
Forum: New User Chat Area
Topic: Converting CPM to neutron flux
Replies: 7
Views: 283

Re: Converting CPM to neutron flux

One cannot translate counts per time into neutron flux unless one knows what the detectors response, geometry & area, moderator used and its thickness, the energy of the neutrons to name a few issues that are required to know so that a flux can be determined - a general definition of a flux is absol...
by Dennis P Brown
Sun Feb 17, 2019 1:53 pm
Forum: New User Chat Area
Topic: Converting CPM to neutron flux
Replies: 7
Views: 283

Re: Converting CPM to neutron flux

Calculating the flux requires knowing the manufacturer's information for that specific detector's response to neutrons - you need to look that up. Otherwise, one needs a bubble detector to calibrate their mfg. specific neutron detector. Edit your post since I am certain you can convert CPM to CPS. ;)
by Dennis P Brown
Sat Feb 16, 2019 2:54 pm
Forum: Fusor Construction & Operation (& FAQs)
Topic: X-ray transformer issues
Replies: 8
Views: 627

Re: X-ray transformer issues

Since surface tension and air being trapped deep in the coil are the main issues, simply "bumping" the item while it is under oil is not likely to remove these types of issues. Certainly it will help for bubbles on the x-former surface. I would suggest, in lieu of vacuum, heating the oil and transfo...
by Dennis P Brown
Sat Feb 16, 2019 12:45 pm
Forum: Fusor and/or General Fusion Theory (& FAQs)
Topic: Fusors and Maxwell's Equations
Replies: 6
Views: 1449

Re: Fusors and Maxwell's Equations

A few comments that may or may not help those that desire to build a demo fusor at a school - either a student or teacher. First and foremost, don't call a demo fusor project by that name. As soon as anyone in admin or safety googles that word, then nuclear fusion, neutrons and possibly x-rays sourc...
by Dennis P Brown
Fri Feb 15, 2019 10:50 am
Forum: High Voltage - Fusor Input Power (& FAQs)
Topic: NST issues
Replies: 15
Views: 773

Re: NST issues

Those pipe fittings will not provide as good a seal as proper vacuum components, so, not gong to be easy to seal the system to get good performance. Also, your valves are not likely to permit good vacuum performance at all.
by Dennis P Brown
Thu Feb 14, 2019 5:31 pm
Forum: High Voltage - Fusor Input Power (& FAQs)
Topic: NST issues
Replies: 15
Views: 773

Re: NST issues

A NST can't power any real fusor even with a voltage multiplier. The frequency is far too small. I used that system to generate 100 kV for an ion gun using very large caps. I use a conventional high voltage transformer for my fusor. A few good things about a NST: a NST isn't likely to kill you if yo...
by Dennis P Brown
Thu Feb 14, 2019 5:08 pm
Forum: Vacuum Technology (& FAQs)
Topic: Cleaning/Repairing Edwards E2M5
Replies: 20
Views: 1490

Re: Cleaning/Repairing Edwards E2M5

Gauges can always mislead. So, confirming that it is accurate is very important. As for my pump, the dis-assembly of the actual internal vacuum pump assembly was done without a kit. I did damage a flat gasket but silicon sealant fixed that. I reused the o-rings but that could be hit or miss - one di...
by Dennis P Brown
Thu Feb 14, 2019 4:00 pm
Forum: Vacuum Technology (& FAQs)
Topic: Cleaning/Repairing Edwards E2M5
Replies: 20
Views: 1490

Re: Cleaning/Repairing Edwards E2M5

Sorry the pump is still making your oil so dirty. By the way, I can only see one pic when I open the link you included - a pic of your tools and teflon tape. Is there only that pic? You cleaned the inside case but did you dis-assemble the actual pump stages? I did this with my pump and cleaned it. T...