If your source is Radium Ra226, I don't have precise data at hand, but the Ra226 half life is many thousands of years! Hi, The half life or Radium 226 is 1620...
... Michel; You have a couple of things here regarding calibration. The CPM scale can be calibrated accurately with a negative pulse generator (pulser) at...
Bill.,how about whomping up a super simple cruit that uses say a 6.3V filament transformer, a clipper and a limiter ( diodes) and maybe a series resistor or...
Bob and Michel, The Oak Ridge Associated Universties page I linked to is interesting. Dr. Frame did gamma spectrography "for fun" on CD check sources and his...
For inexplicable reasons, Frame did not test the ElectroNeurotics machines. On my ENi model 6b, the check source bulge is large and it has an irregular border....
Phil, "Electro Neurotics"...I love it. I never noticed that he didn't test 'em. The ones I've seen sans the foil sticker were small rectangles of brittle,...
Frame's hypothesis that the OCD changed the type of check source material during later refurbishments of all of the brands seems reasonable to me, and it...
Final voltage should be about 1 or 2 volts for GM units, and a negative going peak. Hi George! That sounds like a super idea for the ultimate in an inexpensive...
The GM tube makes a bigger pulse than 1 or 2 volts as you have noticed Tom. The meters generally are very much more sensitive on the order of 10 to 150...
That's reasonable to assume, Phil. Which make / model had the 6-year half life? The correction chart was included in the manual. Those were positively...
Hi! i just want to test my CDV on other things than the sample so i remove the Americium source from an old smoke detector and surprinsly, my CDV-700 dertect...
Hi Michal, First of all it is illegal to remove the source from smoke detectors in the USA and may be in other countries as well. Am241 has two weak Gamma...
Geo; Not a bad idea- maybe a center tapped secondary 6-0-6 V into a bridge with a switch to cut one side out (60/120 Hz). There would have to be a one-shot to...
Bill, instead of a one shot how about a simple resistor-capacitor integrator? For this application, I don't think the waveshape would need to be perfect....
... Not exactly, the glue on one let go and I put it back together. The probe clip is around a cylinder that contains a small spring, a small washer, and the...
Marshall, If you're referring to the circuit diagram referenced on the 725's web page, that's the recommended series resistance and pulse coupling capacitor to...
If I were to build a fully functinal tester, I would no doubt duplicate Bill's testset. The goal here is to provide an almost free/ very simple tester that...
On that note, Marshall, I take back my comment about the resistor not being in the tube! Very probably IMHO it's a "plug 'n' play" feature for those using the...
In a message dated 1/3/06 1:16:29 PM Central Standard Time, GEOelectronics@... writes: If I were to build a fully functinal tester, I would no doubt ...
I use the quartex, modified for lower volume, as my principal urban- prospecting tool. See http://groups.yahoo.com/group/GeigerCounterEnthusiastsPAGE1/files/ ...
Anyone with experiance or advice "retrofitting" a "stock" CDV700 survey instrument with a CDV700RP probe? Would a meter-face replacement and/or HV power...
On the invention of the wheel, see: http://www.ideafinder.com/history/inventions/wheel.htm For Bill's home made Geiger Test Set go to GeigerCounterEnthusiasts ...
Any 900V GM (Geiger-Mueller) probe will work on the CDV-700, including pancake, end-window and thin wall types as well as others. In each case the relationship...
Thanks for the reply GEO but this is what is happening. Using a good, calibrated CDV700 (Lionel 6b and also a Vic 6B), removing the original probes and...
Yes. First we need to verify that your source is Cs-137 of 120 millicuries. this is a lot. Second, how are you removing the beta component from the source. ...
Amersham Model 77302 source calibrator, Cs-137, original activity 141.5 mCi, 12/19/1990, decayed to 100.0mCi 01/02/2006. Yea.. it's a big one, I do have a...
Having problems with message search?
Fill out this form to ensure your group is one of the first to be migrated to the new message search system.
