Search found 119 matches

by Larry Upjohn
Thu Mar 29, 2007 4:35 pm
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: PMT operational characteristics
Replies: 5
Views: 2553

PMT operational characteristics

<t>Hi all;<br/> this is a general question involving photomultiplier tube ops in general. I have two older RCA 7265 PMT tubes (14 stage bialkaly photo cathode rated for 2500 kv operation). I am attempting to revive these tubes for a neutron scintillation detector. The tubes came with sockets equippe...
by Larry Upjohn
Thu Mar 22, 2007 7:15 pm
Forum: Vacuum Technology (& FAQs)
Topic: Yeargh, what a mess!
Replies: 15
Views: 6901

Re: Yeargh, what a mess!

<t>Hi all;<br/> I am trodding a similar path. I just bought an old 1400(even the motor has cast iron end frames). It arrived in a foam packed box and is fairly oily on the exterior. I have run it and it does have a good thumb sucking intake. I have not done a closed vacuum guage test yet. I have a m...
by Larry Upjohn
Tue Mar 20, 2007 7:22 pm
Forum: Fusion --- Past, Present, and Future
Topic: Thiago, Round 2
Replies: 5
Views: 4468

Re: Thiago, Round 2

<t>To go where no one has gone before (sorry I used the PC version) was the phrase that started several generations to explore. For me it was Sputnik and the challenge to catch up. My Mom and Dad expected me to accomplish minimums that were pretty high and I am sure that Thiago is encouraged to achi...
by Larry Upjohn
Tue Mar 06, 2007 10:23 pm
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: photomultiplier question?
Replies: 13
Views: 4816

Re: photomultiplier question?

<t>Sorry I didn't get back sooner. Some how the side science often suffers from the political science demands of the day. The units are automotive controllers and ended up minus whatever detectors were originally in there. Was able to bid on and win two small 1.1kvdc power supplies on Ebay and am no...
by Larry Upjohn
Fri Feb 02, 2007 8:19 pm
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: photomultiplier question?
Replies: 13
Views: 4816

Re: photomultiplier question?

I just sent a long reply to John Hendron and hopefully it will echo here. If not I will post an answer later. LRU.
by Larry Upjohn
Thu Jan 25, 2007 4:44 pm
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: photomultiplier question?
Replies: 13
Views: 4816

Re: photomultiplier question?

<t>Thanks for your response. I checked the surplus analyzers over again last night and came to the conclusion that I don't want to waste the time trying to kludge these analyzers attempting to recover a possible photomultiplier. They were sealed units and had to be purchased before determining what ...
by Larry Upjohn
Wed Jan 24, 2007 7:54 pm
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: photomultiplier question?
Replies: 13
Views: 4816

photomultiplier question?

I have come across some surplus NOX (automotive smog certification) instruments and have a suspicion that they could be a source of photomultiplier tubes and associated powersupplies. Anybody have any ideas on this? LRU.
by Larry Upjohn
Wed Jan 10, 2007 10:40 pm
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: Circuit values for PMTs
Replies: 5
Views: 2976

Re: Circuit values for PMTs

Hi all;
I am late for this thread but does anyone have pinouts and/or specs for the RCA 7265 PMT. I know it is a 14 stage S20 tube.
I got two surplus an number of years ago and I want to fire them up and try some neutron counting with them now. Thanks for any help here. LRU.
by Larry Upjohn
Wed Jan 10, 2007 10:23 pm
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: Cloud Chamber
Replies: 10
Views: 5253

Re: Cloud Chamber

<t>Hi all;<br/> I am a little late on this thread. I wanted to relate my exposure to the cloud chamber. Some time ago I was visiting the E.O. Lawrence Hall of Science Museum located on the Lawrence Berkeley Laboratory Campus ( I don't know if it still open to the public since 911). There was an oper...