Collection of information about russian SNM tubes

This area is for discussions involving any fusion related radiation metrology issues. Neutrons are the key signature of fusion, but other radiations are of interest to the amateur fusioneer as well.
Post Reply
Lukas Springer
Posts: 15
Joined: Sat Mar 03, 2018 9:37 pm
Real name: Lukas Springer

Collection of information about russian SNM tubes

Post by Lukas Springer » Tue Oct 16, 2018 8:32 am

Some information was brought together in a trading post, this is that information condensed down before the thread in trading gets deleted.

As many of you are aware some russian SNM tubes are floating around and there seems to be much confusion on how to use them,
This problem is not made easyer by the fact that there are many different types of detectors under the same name.

SNM tubes can be:
-Boron 10 as cathode coating in corona tubes (SNM9-14)
-10BF3 as fill gas in proportional tubes (SNM3, 5, 8 & 20)
-Helium 3 corona (see link below)
-Helium 3 proportional (see link below)

It's hard to get datasheets for most of them, but a russian manufacturer is still supplying some of the He3 tubes, with datasheets: ... n-counters

I have only worked with my SNM-18-1 so far, which is a 4.6 bar 3He corona tube, if you have a different detector please post your results here :)

We all know the paper by Bob Higgins, which I would like to add to.

This is Higgins' circuit for driving 3He corona tubes:
Which gives me the following trace for a neutron event:
DS1Z_QuickPrint5.png (36.29 KiB) Viewed 418 times
This is the circuit described by Consensus-group in their SNM-18-1 Datasheet:
corona tube.PNG
Which gives me the following trace for a neutron event:
DS1Z_QuickPrint4.png (36.54 KiB) Viewed 418 times
As you can see, using 16k to "terminate" the signal all of the high impedance corona noise is removed and all you get is a clean pulse, which can easily be amplified, needing almost no noise rejection.

The current through my tube is 8 µA with 100 MOhm and 14 µA with 47 MOhm (both at 2400V), allthough the output signal dosen't seem to change in amplitude with different currents, which might be explained by the very constant voltage across the tube.
I'd assume the same circuit works for 10B corona tubes aswell.

I can't say anything about my tubes sensitivity, but 4.6 Bar 3He are 4.6 Bar 3He.

If you have any further information about any of the SNM tubes feel free to add it here!


Post Reply