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FrozenGate by Avery

Bicron Surveyor M mod - PIC scaler BIG POST

More experimentation today, this time getting the side well to work properly.
I'd been told by an ex harshaw employee via email that the well is thin enough to accept/pass through of 15KeV. Sure enough, he was right.

Note how sharp the spectrum looks now..

Something worth noting here, the 32KeV X-ray

decay channel is by β− (that is the conversion of a neutron into a proton with the release of an electron and a electron anti-neutrino) which makes the daughter Ba-137 in an excited state called Ba-137m - this returns to ground state by the
32KeV x-ray emission. The 662KeV is gamma.


A GM detector has a hard time picking up on this source as most of the 662KeV Gammas pass straight through the detector. At ~0.3uCi the tube registers on average 1500CPM (electrodes at the centre) and if placed with the electrode tips facing the centre of the tube, 6500-7000CPM is observed briefly.
However, a much different story occurs when we put the tube into the scintillation detector well. A count rate of 125,000 CPM is obtained. The attenuation in NaI/Tl is greater than a GM tube. Higher Atomic mass.


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I'm going to be sending the new 2"x2" probe to a specialist as IO now think there might be a problem with the probes sealing around the well or that the crystal is cracked.

- Either way I have noticed an issue in the higher energy part of the spectrum that makes the higher energy resolutions invisible or slow to surface.



hmm.... :undecided:
 





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