Theremino Calibration

[Mark Rowley]

Hello all. I am currently running Theremino MCA with a GS-1100A and a Bicron 1.5x2.25 scintillation detector. I'm having difficulty with calibration while using Cs-137 and Lu-176. Seems that I'm consistently off by about 50keV between the Lu-176 peaks and the 661 keV cesium peak.

I've also noticed a similar issue when testing uranium ore samples. If the lead daughters are aligned, the Bi-214 peak is off about 50 as well.

Any suggestions?

image.jpeg (220.03 KiB) Viewed 11141 times

[Mark Rowley]

Here's a uranium ore pic showing the calibration issue with Bi-214.

image.jpeg (258.1 KiB) Viewed 11140 times

[Mark Rowley]

Figured it out. Had a slight issue with the Energy Linearizer. All in order now.

[Sesselmann]

Mark,

Theremino does some strange things with the linearity, are you seeing the same non linear response in PRA?

if so what are the specs of your VD?

Linearity varies from detector to detector.

Steven