Search found 240 matches

by Rex Allers
Mon Dec 10, 2018 4:03 am
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: Gamma-ray Spectrum, CP-1 Graphite Memento
Replies: 11
Views: 283

Re: Gamma-ray Spectrum, CP-1 Graphite Memento

That's quite an impressive GS measurement tool and shield. Do I interpret correctly that the scan was almost 4 days?
by Rex Allers
Tue Nov 20, 2018 10:32 pm
Forum: Fusor Construction & Operation (& FAQs)
Topic: Fusor from Poland
Replies: 8
Views: 917

Re: Fusor from Poland

Acting as net nanny... You should post in Please Introduce Yourself section (per forum rules, it should have been your first post.) Also, per rules, your name should be your full real name, not a shortened tag. Please edit your account settings to change your user name. Your posts will remain but yo...
by Rex Allers
Tue Nov 20, 2018 10:00 pm
Forum: Advanced Technical Discussion Area
Topic: Harbor Freight freebie meters
Replies: 12
Views: 947

Re: Harbor Freight freebie meters

About: "How does one turn off the highlighting of search words?" I'll take a stab at it. Links in a message usually look like gibberish and don't give much context. Because of this I usually copy the text of the header before the link I post. If I am referencing a reply message in a thread I might a...
by Rex Allers
Sat Oct 27, 2018 1:51 am
Forum: FAQs: High Voltage
Topic: #5 FAQ - Grounding in a fusor system
Replies: 8
Views: 3187

Re: #5 FAQ - Grounding in a fusor system

Richard, These FAQs are a great resource but I think the current sensing part shown in the main star topology diagram that is in series in the ground return from the chamber is still a bit confusing or misleading. The diagram shows the meter (labeled Ma) in parallel with the current sensing resistor...
by Rex Allers
Mon Aug 27, 2018 9:03 pm
Forum: Images du Jour
Topic: I purchased, yet, another pump!!
Replies: 2
Views: 850

Re: I purchased, yet, another pump!!

Congratulations on another score.

That's a nice clean vacuum gauge in your picture. Don't think I've seen one like it. Is that some commercial unit?
by Rex Allers
Fri Aug 17, 2018 4:14 am
Forum: Please Introduce Yourself
Topic: Hello
Replies: 2
Views: 554

Re: Hello

ha ha. Funny typo in "grabage". It was, when you grabbed it out of the dump.
by Rex Allers
Wed Jul 25, 2018 10:23 am
Forum: Announcements and Site Administration Topics
Topic: How did you find our Fusor forum?
Replies: 8
Views: 1119

Re: How did you find our Fusor forum?

How I got here: I don't remember exactly. It was shortly after Fukushima and I, like many, was learning about rad stuff and detection devices. I might have got here from searches about gamma spec or I might have found a reference from one of Geo's yahoo groups -- geiger or gamma spec. I immediately ...
by Rex Allers
Wed Jul 04, 2018 8:44 am
Forum: High Voltage - Fusor Input Power (& FAQs)
Topic: xray transformer
Replies: 7
Views: 1682

Re: xray transformer

Simple ohms law doesn't apply on a transformer. The ohms you are measuring are at DC. The primary will have a large inductance. At the intended operating frequency of the transformer, hopefully that inductance will provide inductive reactance that won't draw the kind of power your DC calculation see...
by Rex Allers
Fri Jun 22, 2018 1:21 am
Forum: Fusor Construction & Operation (& FAQs)
Topic: Ballast resistor construction
Replies: 11
Views: 2637

Re: Ballast resistor construction

Nice work, Dan. One minor suggestion, possibly not necessary... At minimum, cut or file the sharp square corners of the resistor terminals to make them rounder. Better would be to also add a metal shape or build with solder a rounded or blob shape to avoid easy arc flash starting points (pun intende...
by Rex Allers
Sat Jun 16, 2018 11:29 pm
Forum: FAQs: Neutron - Radiation Detection
Topic: FAQ - Extensive paper on neutron activation
Replies: 12
Views: 3132

Re: FAQ - Extensive paper on neutron activation

Thanks. For some reason I (incorrectly) interpreted that "the book" was something coming from IAEA. I guess I was thinking along the lines of the Gamma-ray Spectrum Catalogs that can be had as pdf's from INL. (Although I tried a link I had saved today and it failed. Then, starting at the top of inl....