Search found 242 matches

by Bob Reite
Fri Dec 08, 2017 9:23 pm
Forum: New User Chat Area
Topic: How dangerous are X rays?
Replies: 5
Views: 159

Re: How dangerous are X rays?

At 30 KV and 10 mA, X rays coming out the viewport is a major concern. When operating at that level, I was using a mirror to view the grid and standing at least 10 feet away from the machine out of line of sight from the viewport. At 50 KV and 8 mA, I was getting some X-ray backscatter from the view...
by Bob Reite
Sun Dec 03, 2017 1:00 am
Forum: High Voltage - Fusor Input Power (& FAQs)
Topic: multiplying dc
Replies: 6
Views: 258

Re: multiplying dc

Unless you are using a bubble detector, which *only* responds to fast neutrons (if you don't overheat it and get big bubbles), you need to be at 25 KV or higher to be well enough above the noise floor of your counter. I usually operate at 40 KV. Needless to say at this voltage, the stainless steel o...
by Bob Reite
Sat Nov 11, 2017 11:19 pm
Forum: Fusor Construction & Operation (& FAQs)
Topic: What do you need to do to run a vacuum system unattended
Replies: 6
Views: 264

Re: What do you need to do to run a vacuum system unattended

I run my turbo and roughing pump unattended with no special precautions and have not had a problem. The turbo is run in "standby mode" (reduced RPM) to save some wear on it, yet keep the chamber under a good vacuum so I don't have to go through a bakeout like I would if I let it go to atmosphere. I ...
by Bob Reite
Fri Nov 03, 2017 1:19 am
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: Increasing the useful life of bubble detector tubes
Replies: 13
Views: 592

Re: Increasing the useful life of bubble detector tubes

Think I will try that drop of water trick with one of my two detectors and see if it lives longer.
by Bob Reite
Thu Nov 02, 2017 12:07 am
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: Increasing the useful life of bubble detector tubes
Replies: 13
Views: 592

Re: Increasing the useful life of bubble detector tubes

My failed bubble detector never showed signs of leaking. Just that the bubbles would not compress anymore.
by Bob Reite
Mon Oct 30, 2017 12:35 am
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: Increasing the useful life of bubble detector tubes
Replies: 13
Views: 592

Re: Increasing the useful life of bubble detector tubes

For convenience, I plan to keep the REM ball at the same distance, but since I know the mREM/h reading is valid if for some reason I have to double distance the reading will be 1/4 what it was at the old location for the same system output.
by Bob Reite
Mon Oct 30, 2017 12:29 am
Forum: Announcements and Site Administration Topics
Topic: A Nightmare editing fusioneer listings
Replies: 11
Views: 434

Re: A Nightmare editing fusioneer listings

When support for Windows 7 goes away in 2020, the remaining Windows machines will have their drives formatted (after backing up data files) and Linux Mint installed. The few programs that require windows that I run will be run under WINE.
by Bob Reite
Sun Oct 29, 2017 5:56 am
Forum: Announcements and Site Administration Topics
Topic: A Nightmare editing fusioneer listings
Replies: 11
Views: 434

Re: A Nightmare editing fusioneer listings

Even the latest version of Internet Explorer is very poor at following current HTML5 standards. Firefox even has issues with some sites. Google Chrome is my browser of choice now.
by Bob Reite
Sun Oct 29, 2017 5:54 am
Forum: High Voltage - Fusor Input Power (& FAQs)
Topic: High Voltage Multiplier Issue
Replies: 29
Views: 1290

Re: High Voltage Multiplier Issue

Get 10 100 M HV rated resistors and put them in series for your 1 Gigohm resistor.
by Bob Reite
Sun Oct 29, 2017 5:44 am
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: Increasing the useful life of bubble detector tubes
Replies: 13
Views: 592

Re: Increasing the useful life of bubble detector tubes

My first tube lasted about 9 months. The failure mode was that the bubbles would no longer compress. It could still be used by counting bubbles before and after and taking the difference, until it was so full of bubbles that you could not keep track of them, but the accuracy would be questionable. M...