BC-720 Replica

[Jon Rosenstiel]

I just placed a PDF in the "Files" section detailing my progress on making a BC-720 replica.
Comments welcome.

Jon Rosenstiel

[Richard Hull]

Really nice report, Jon! Thanks for sharing. It shows that where there is a will, there is a way. I have printed it out and it is now in my notbook on radiation detector schemes. I wish you had a hot radium source so that you could see just how far down in the scudd the gamma pulses are compared to neutron or cosmic ray events. It's pretty dramatic.

Richard Hull

[Jon Rosenstiel]

Thanks Richard.
I have tested the detector with a piece of uranophane/autunite ore I have, (just under 7mR/hr gamma). With the discrimination set at 50mV the gamma is completely blocked out and all I get is the cosmic ray background.

Jon Rosenstiel

[Tom Dressel]

I was wondering if it is possible to make a BC-720 scintillator "replica" by casting a rubber "negative" of the Zns doped block.

This could be done by glueing concentric PVC cylinders or rings to a base, then filling the "positive" with modeling rubber, then use the resultant "negative" to cast the Zns doped block, and then finally back filling with clear resin.

One would, of course, have to be carefull to polish the PVC "positive" and eliminate air bubbles at all stages by carefull mixing and out gassing bubbles etc. But if this method works once the "negative is made one could essentially go into production making BC-720 scintillators.

Tom Dressel

[Jon Rosenstiel]

I didn't have much luck with a rubber mold, the Hornyak buttons I tried to make came out pretty rough.

I bet a "negative" machined from HDPE would work well. Getting the hardened "replica" out of the mold may be a bit tricky tho. Have to make the mold so compressed air can be directed in behind the "replica" to push it out.

Jon Rosenstiel

[Tom Dressel]

Thanks Jon, there is nothing like the voice of experience!

Tom Dressel