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Mounting Frank's BGO Crystals to a PMT
Posted: Tue Mar 14, 2006 6:13 pm
by Richard Hester
I just received a 12 X 30mm BGO crystal from Frank Sans - such a deal! The form factor is a little awkward for mounting on a standard PMT. I was thinking of using a lucite light pipe between the crystal and the PMT, and wondered how others have solved this problem. I suppose I could be crude and just mount the crystal to one of my 2" square PMTs and ignore the wasted photocathode area on the PMT, but the esthetics of that choice bother me a bit....
Re: Mounting Frank's BGO Crystals to a PMT
Posted: Tue Mar 14, 2006 9:42 pm
by bwsparxz
I did just that. Mounting it directly to a 2" round PMT. Works great. And I asked that same question to Frank about using a lightpipe. He recomended using the direct approach. And again, thanks Frank for such a great deal on these.
Re: Mounting Frank's BGO Crystals to a PMT
Posted: Tue Mar 14, 2006 10:58 pm
by Q
just got mine as well, and yes, thanks frank!
actually i was thinking about trying to use a photodiode to make a super small detector. problem is finding one with the right spectral responce.
but if that doesn't work i have a small 1" pmt that i'll probably use.
Q
Re: Mounting Frank's BGO Crystals to a PMT
Posted: Tue Mar 14, 2006 11:56 pm
by Frank Sanns
Glad you guys like the product.
Richard,
Buy more xtals to fill the face of your PMT!
I am building a 5 inch diamter with 19 xtals. Just wait until HEAS next year. I will be able to detect Richard's house from my hotel room!
Brian,
From your email, sounds like you have your BGO up and running and it can detect at double the distance compared to your NaI. Sounds good to me.
Q,
Using just one xtal and a 1/2 compact PMT you should be able to get a really sensitive and tiny detector. Try walking around outside of the nuclear medicine departement with one of these xtals. You will not believe what you will detect. It is almost spooky how efficient these things are.
Frank S.
Re: Mounting Frank's BGO Crystals to a PMT
Posted: Thu Mar 16, 2006 5:10 pm
by bwsparxz
I took my BGO detector to wrk with my today- I spend alot of time on the road. I noticed my counter background was about 80 - 100 CPM. Any bridge or large concrete object raised it to 200 - 300 CPM. Also near large rock faces had the same effect. I checked to make sure I did not have a light leak and placed some electrostatic sheilding foil around the tube. I do not have any Mu-metal so it could be magnetic. OR Is the BGO's that sensitive. I just checking to see if this is normal or I have a problem.