Gamma Spectrometry Forum

Hello all, I'm Lyle aka Lylo from BC, Canada

I am a retired community college instructor, mostly prep level Math as well as Chem and Phys where I usually managed to work in a radiation unit including the intro courses. My Chem PhD thesis was in low energy electron spectroscopy so I never got to play with too many gamma rays (!), but rather threshold excitations and ionizations of atoms and simple molecules from inelastic collisions with monochromatic electrons in the 0-30 eV range. Wherein I did get to deal with a lot of so-called zero energy electrons, reminiscent of cat herding. My ion detector at the end of a electron velocity selector, ion drift chamber, some accelerator plates and a mass spec, was yup none other than a good ol’ photomultiplier carefully denuded of its glass tube. Sheesh, some technologies never grow old. But it seems I have--that was 44 years ago!

My motley hardware collection today consists of 3 geiger counters, an Eberline Radiation Monitor RM 14SA with pancake geiger and plastic scintillator probes. And a once working but now won't boot TSA MCA-465, an apparently rare handheld gamma spec with an internal 1”x 2” NaI(Tl) probe that I could always scavenge if I can’t get it going I guess.

A while ago I was looking at a nice GS1100 based system I think it was, on eBay that turned out to be one of Karl’s items but while I was lobbing him questions on the old forum, someone else scooped it of course, darn. So yesterday when I saw another listing from Karl (recognized his eBay handle) for a new GS1100A based kit with a modified square Bicron 1600-2265 probe for what I thought was also a pretty decent deal, this time I skipped the 20-questions part and just jumped at it--thanks Karl! Can’t wait for it to arrive. Seems like I have always wanted a gamma spec. Do a lot of people say that? Happy to be a part of this forum, seems like a great resource and a great group.

I was sideways involved in some ZEKE spectroscopy, also a long time ago, when I was at Brookhaven. Gently herding electrons...

Welcome Lyle!
I noticed in my eBay watched items this morning, that Karl sold that combo unit. That's a hard to beat price for nice entry level gamma spectroscopy system. It's nice to know someone who is now a part of the group snagged it up.
Cheers, Tom

Hi Lyle!

Great to have you on board!

Happy to do business with you, the kit went in the mail today so let me know when you get it!

Yes, the first time I sold a kit I sold the very first probe I ever built. It was a PMT from Tom (I greatly benefited, and still do, from his excellent experience and helpful attitude), a soviet surplus crystal, and the GS1100A from Steven. That combo turned out to be a real killer, with the probe doing around 7% @ 662 keV.

The kit you bought (or I should say, the probe) does not compare in terms of resolution, but it is also reflected in the pricing. However, to get started and to be able to pick up gammas up to 2614 keV, beyond which we will hardly come across much of significance, I think the kit is great.

Also note that resolution is not the solution to every question: I had no problems quantifying Cs137 in soil as I mention in the last post in this thread from old forum:
http://www.gammaspectacular.com/index.p ... &path=1283
so in that case, sample geometry and background reduction is what is important, and not the resolution per se, as there are no other peaks close by to mess with the 662 keV peak.

So, when you feel you have outgrown that probe and maybe take your lead shielding to new dimensions, consult with Tom on a PMT, get a nice housing from Steven, and invest in a soviet surplus crystal. I recommend the seller "Levytskyi", whom I have traded with (Actually Luuk recommended him to me).

Cheers Lyle, and welcome to the forum, I like the way you refer to focusing of electrons as "reminiscent of cat herding", very true indeed. The normal understanding is that like charges repel, but if you have nothing else to do one day you can take a look at a different explanation here at http://groundpotential.org , it's a little side project I work on when I have time.

Thx everyone. Yes, herding electrons. ZEKE is good name for them. They certainly behave very differently at low kinetic energies than they do above 50 keV. Steve, thx and yes I'll have a better look at that site, looks intriguing, if I can manage to follow it. From your "other projects" link I can see you are up to all sorts. Tom, yes a great price for a starter kit, I agree. Karl, no I'm not expecting 6.5% at this price point, but as you say, there is still a lot one can do--that link on the well probe was very interesting.. I like your suggestions about how to put together a higher end probe. I watched Tom's YouTube video and it would be very helpful should I try to roll my own at some point. I'm actually not entirely new--I joined the old forum last year to ask about a kit on ebay that turned out to be yours Karl--is this the first sold kit you mentioned? http://www.gammaspectacular.com/index.p ... t&path=938 Too bad I missed it. Anyway, I got some great advice there, and of course again now, much appreciated. Been going through the new and old forums, such a lot of great information. Again, thx to all for the warm welcome.

Hi Lyle

The link was broken, but yes, the first kit I ever sold was with my 30x70mm soviet crystal-based probe, that had a PMT from Tom and my first GS1100A.
Really a great probe, I even went to lengths anodizing it in black, very sexy.

Glad to hear you find the forum informative! I think the kit that is in the mail now will both answer some questions, and pose a few new ones!