Search found 289 matches

by luuk
21 Jan 2022, 06:41
Forum: Detectors
Topic: HPGe Repair And Fet Swap
Replies: 8
Views: 252

Re: HPGe Repair And Fet Swap

Hi Lukas, As far as I remember the 2n4857 worked also good as cooled FET. Btw I looked at the vacuum seal that is used in your detector, interesting to see it work with an O ring, in the "old" days we used always Indium sealing, but then the hood of the detector was mounted with a flange t...
by luuk
20 Jan 2022, 08:50
Forum: Spectrum
Topic: PMT give light !
Replies: 6
Views: 214

Re: PMT gives light !

Hi Tom,
Yes it is really rare that this happens, so don't worry your pmt's are all good I expect!
Luuk
by luuk
20 Jan 2022, 00:41
Forum: Spectrum
Topic: PMT give light !
Replies: 6
Views: 214

Re: PMT gives light !

Hi Steven, Yes, there is a small leak somewhere so the “gas” is Nitrogen (actually air) that gives this particular color. The pmt that I wrote about 7 years ago, I tested it last year again and still gave the same “light show” so for some reason the leak closed. If not the vacuum was lost a long tim...
by luuk
19 Jan 2022, 07:55
Forum: Detectors
Topic: HPGe Repair And Fet Swap
Replies: 8
Views: 252

Re: HPGe Repair And Fet Swap

Hello Lukas, Great work you did on the HpGe detector, with a very nice result! When I was building Ge detector a long time ago we used most times amplifier with the Fet outside the cryostat, the cooled Fet was just beginning to get more popular then. The Fet’s were very expensive 300$ (in 1982) we b...
by luuk
19 Jan 2022, 07:19
Forum: Spectrum
Topic: PMT give light !
Replies: 6
Views: 214

PMT give light !

Hi Guys,
Do you want to see some nice pictures of a strange effect in a pmt!
If interested please read the pdf.
Luuk
by luuk
25 Nov 2021, 06:12
Forum: Spectrum
Topic: Cs-137 - quite a banal spectrum, but out of a new hardware :)
Replies: 4
Views: 145

Re: Cs-137 - quite a banal spectrum, but out of a new hardware :)

Hello Svilen,
Great spectrum and a very nice resolution, well done!
Good to see that you are happy with your new detector I know for sure that your detector will last for a long long time.
Have lots of fun with it.
If you have some more spectra please share it with the group.
Luuk
by luuk
31 Oct 2021, 04:50
Forum: Detectors
Topic: CsI(Tl) and SiPMs?
Replies: 3
Views: 177

Re: CsI(Tl) and SiPMs?

Hi Cole?
I don't see a problem, if you simply separate the crystals and the sipm's by e.g. aluminum foil there is no crosstalk at all.
Luuk
by luuk
26 Oct 2021, 05:52
Forum: Detectors
Topic: A bad crystal but still nice to look at.
Replies: 2
Views: 144

Re: A bad crystal but still nice to look at.

Hello Lukas, Growing a good crystal is tricky, small errors can have big consequents. Maybe there went something wrong in the heating or cooling down process, not sure. I have seen it before it simply happens now and then but with the proffecional growers not too often. Just made some pictures from ...
by luuk
22 Oct 2021, 05:36
Forum: Detectors
Topic: A bad crystal but still nice to look at.
Replies: 2
Views: 144

A bad crystal but still nice to look at.

Hello guys, The growing process of scintillation crystals is very complicated and sometimes it goes wrong, in this case with a 80x80mm NaI(Tl) crystal. The effect can be interesting although the crystal is not usable, but I thought that you would like to see this. I have seen a few times but this on...
by luuk
28 Aug 2021, 00:48
Forum: Detectors
Topic: Purpose of optical coupling gel
Replies: 12
Views: 425

Re: Purpose of optical coupling gel

Hi Tim,
I don't know were you are located but if it is in Europe I can send you some optical gel,
if you are located in the USA it is more easy to contact Tom Hall from Irad.
Luuk