Gamma Spectrometry Forum

Getting space between the actual shield and the detector can reduce the low energy background qiite a bit but then the amount of lead skyrockets.....

I dont want to barge in...but does 210Pb not have a strongish peak at 15.5 keV or so?

If as the picture shows 47 is being identified at 48 point something...then taking 1.5 keV from 15 pyts you within shouting distance of 12.5 keV?

Lars

Im a little dissappointed now...... good for you in pursuing it though!

Maybe try measuring it a few cm away from the detector? If its some kind of true coincidence peak that should reduce it or eliminate it? If its still visible then it is not simply a sum peak....

That really is the oddest thing......

Out of curiosity....I ran this with a Radiacode in a shield for a week and saw precisely ......nothing.

I should have known the Swedes would let me down with their fake pellets!!!

lars

Sorry....forgot.......the line that Interspec seems to be present at 1240-ish is a Bi-214 line at 1238.1 keV. With possible contributions from Ac-228 at 1245 keV and 1246 keV. Please note - these are in relation to this synthetic spectrum. Im not saying this is what you are seeing in yours. But base...

I still think your energy calibration might be a bit "off" but its of minor consequence. To take a look I made two spectra with MCNP - both with 1000 Bq of U238 and 232Th in equilibrium with no 235U. One on HPGe and one on NaI under the same conditions. With 40K. And with the list of peaks...

This chap has landed himself in a bit of a pickle..... The cubes that that website used to sell (not any more) were the "cores" from the old Soviet detectors. These are harmless. The hazmat response was ridiculous. BUt the problem for him is that those cubes , according to what I have read...

I got the lead from a whole body counting room that was being dismantled a decade ago....was probably many tons of the stuff but they were building a new one and reusing the lead and I just managed to grab a few blocks. They were just sitting in the garage waiting for their time.... When that room w...