> On Dec 2, 2020, at 2:51 PM, SWISSNIXIE - Jonathan F. <[email protected]> > wrote: > > The last chart shows almost identical counts for the mantle on the SMB-20 > (gamma tube) and the SBT-11A (alpha tube) i think that's the one Paul uses.
Thorium is a good beta source. That's why the SBM-20 works so well. There was a discussion about alpha windows on the GeigerCounters list a while back. The SBT-11/A has a window that's thicker than a "true" alpha tube. The larger Soviet "alpha" tubes with multiple anodes use a rather thick material that you can actually touch without popping it like a soap bubble. As for smoke detectors, it is in fact illegal to open one up and use it as a source—in the US, anyway. At the same time it's legal to throw one in the trash so it can be crushed by a bulldozer while it's being buried in a landfill. This makes no sense, of course. I have a couple that I use as alpha sources all the time. You can come to my house and confiscate them if you like. I can get more quite easily. Terry Bowman, KA4HJH "The Mac Doctor" Q: Should car stereo speakers be pointed to the rear for more thrust or up for more traction? A. On long trips, the 20- to 30% improvement in gas mileage you might get with speakers pointing to the rear is certainly worthwhile. On the other hand, if you drive on snow or ice, the extra traction of speakers pointing upward gives you added control. Don Lancaster -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/D93C3AAF-3021-4CCD-80B6-1EC2B7FD5E0B%40gmail.com.
