Search found 19 matches

by gary_f
Wed Nov 26, 2008 12:17 am
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: CR-39
Replies: 4
Views: 3015

Re: CR-39

<r>20 mrem to 25 rem is the claimed dose range. The spec sheet is here:<br/> <br/> <URL url="http://ldrsolutions.landauerinc.com/PRODUCTCATALOG/content/documents/39_NeutrakSpecifications.en-US.pdf"><LINK_TEXT text="http://ldrsolutions.landauerinc.com/PRO ... .en-US.pdf">http://ldrsolutions.landaueri...
by gary_f
Tue Nov 25, 2008 5:38 pm
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: Bubble Dosimeter
Replies: 25
Views: 9898

Re: Bubble Dosimeter

<r>These are the terms I was given recently by Bubble Tech:<br/> <br/> "In order to meet all Canadian Export requirements, I am required to sell to a company that has a Federal ID Tax Number. The current cost for a BD PND is $135 USD each with a minimum order of $300 USD plus S/H/I (~ $150 USD). I w...
by gary_f
Mon Nov 24, 2008 8:47 pm
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: CR-39
Replies: 4
Views: 3015

CR-39

<t>Frustrations with Bubble Tech led me to a conversation with a health physicist where I work. He suggested loaning me a Landauer CR-39 based dosimeter. The Neutrak 144 is a little chip of plastic, sensitive only to fast neutrons, and inexpensive. The downside is that you have to send it away to ge...
by gary_f
Sun Aug 31, 2008 5:01 pm
Forum: Vacuum Technology (& FAQs)
Topic: Mystery solved
Replies: 1
Views: 1989

Mystery solved

<t>A previous post explained my problem with suddenly degraded performance of my Edwards vacuum pump. I changed the oil several times, it didn't help. I had about resigned myself to tearing it apart. I had soldered a brass flare fitting onto the pump inlet pipe that I used to connect my vacuum gauge...
by gary_f
Fri Aug 29, 2008 6:24 pm
Forum: Vacuum Technology (& FAQs)
Topic: Edwards pump
Replies: 7
Views: 2937

Re: Edwards pump

Richard
These readings were at the pump head, blanked off with no chamber. Have you seen these little black specks before?
by gary_f
Fri Aug 29, 2008 3:34 pm
Forum: Vacuum Technology (& FAQs)
Topic: Edwards pump
Replies: 7
Views: 2937

Re: Edwards pump

<t>I think I might have spotted the problem. I looked closely at the oil I drained to see why it's a little dark. I see thousands of tiny, tiny black pinpoint particles. I'll bet it's burned oil, maybe from little electrical events going on inside the pump. When I added the filter capacitor, I chang...
by gary_f
Fri Aug 29, 2008 12:00 am
Forum: Vacuum Technology (& FAQs)
Topic: Edwards pump
Replies: 7
Views: 2937

Re: Edwards pump

<t>My supply isn't center tapped it's end tapped - I have a hipotronics 30kv 600VA transformer I took out of a hi-pot tester. So relative to ground (the pump) I'm half wave bipolar.<br/> <br/> I'm pretty sure it's the pump because I'm running it blanked off now, with out the chamber and voltage. It ...
by gary_f
Thu Aug 28, 2008 6:01 pm
Forum: Vacuum Technology (& FAQs)
Topic: Edwards pump
Replies: 7
Views: 2937

Edwards pump

<t>Thanks for the reply, Dave, I should have explained myself better. When the vacuum performance changed overnight, I changed the oil. No change, still 200 microns. <br/> <br/> When I open the ballast valve, it has no effect, still 200 microns. Does this mean that the second stage is the problem? M...
by gary_f
Wed Aug 27, 2008 6:10 pm
Forum: Vacuum Technology (& FAQs)
Topic: Edwards pump
Replies: 1
Views: 1791

Edwards pump

<t>My Edwards E2M2 pump suddenly went from 3 micron to 200 micron. Anyone have experience with this pump? Straightforward? Seals? Special tools needed? Thousands of parts ready to fly out when I open the case?<br/> <br/> I looked at some of the old posts on repair but didn't see anything for this pu...
by gary_f
Mon Aug 25, 2008 11:46 pm
Forum: Fusor Construction & Operation (& FAQs)
Topic: voltage, current, pressure and temperature
Replies: 9
Views: 2953

Re: voltage, current, pressure and temperature

<r>I posted this out of order above, so I'll repost.<br/> <br/> Thanks everyone! It's pretty clear now that I have more cleaning to do. I also see that nudging up from below is better than forcing from the top. As Richard put it, a feeling for conditions at "the edge" is starting to sink in.<br/> <b...