Russian TUBES COUNTERS OF NEUTRONS SNM9 LOT OF 22

[George Dowell]

on ePay. No connection with seller.

Odd values of operating Voltage etc.

George Dowell

[Steven Sesselmann]

I actually have one of these tubes, given to me by John Hendron, but this tube has me puzzled.

The voltage range is not like a proportional counter at all, it looks more like a GM tube. At around 600 volts it operates like a geiger tube, with around 40 massive clicks per minute, and is sensitive to gammas from my CS-137 source. And at just over 700 Volts, there appears to be a voltage breakdown, and a continuous plasma discharge.

Reading the notes on eBay it sounds like this tube operates in a different mode to the regular neutron counters we are familiar with here.

It mentions continuous corona discharge...

Can anyone shed some more light on this?

Steven

[George Dowell]

Steven, can you test the tube itself to see if there is any radioactivity coming from it?
ALA 185 keV?

George

[Carl Willis]

I searched the part number on Google.ru and got more information.

Basically, this is a "corona counter" (relatively unfamiliar in the US), lined with enriched B-10, with applications in down-hole well logging.

For more info, see this document from Tomsk Polytechnic University:

http://portal.tpu.ru:7777/SHARED/s/SYM/ ... -12-13.doc

A few choice excerpts, roughly translated:

>Бор вводится в счётчик в виде твёрдого покрытия на катоде (коронные счётчики СНМ 9-14) или в виде газа – трёхфтористого бора BF3 (пропорциональные счётчики СНМ-3,5,8,20).

>Boron is introduced into the counter as a cathode coating (in corona counters SNM9-SNM14) or in gaseous form as BF3 (proportional counters SNM3,5,8,20).

What this tells us is that the tube type, a "corona counter," is distinguished in the Russian language from proportional counters, and that some of the SNM series are boron-lined corona counters and others are BF3 proportional tubes.

The theory of operation of a corona counter is described:

>В коронных счётчиках непрерывно, независимо от наличия ионизирующего излучения, протекает небольшой (~1 мкА) ток коронного разряда. Ионизирующие частицы регистрируются по импульсу тока, возникающего на фоне тока короны. Величина импульса пропорциональна начальной ионизации. Коронные счётчики используются для регистрации тяжёлых заряженных частиц.

>In corona counters, a small corona discharge current (~ 1 microamp) flows continuously regardless of the presence of ionizing radiation. Particles are detected by a current pulse, propotional to the ionization, that is superimposed on the corona current background. Corona counters are used for the detection of heavy charged particles.

The eBayer's price is commensurate with that advertised by various Russian tube dealers, although the eBay lot is quite a bit larger than I think would interest most people.

-Carl

[George Dowell]

Thanks for explaining.

George Dowell

[Steven Sesselmann]

Carl,

Thanks for the references, although the russian doesn't make much sense to me, the diagrams and equations can give us some hints.

I actually gave up on this tube, but now it looks as if it is going to provide some interesting experimentation after all.

I will need a neutron source to test this tube, fortunately I think I know where I can find one.

Steven

[Richard Hull]

The volume is relatively small and if they are functional in their basic mission, they would not be particularly efficient, I would imagine. It would be cool to obtain one and play with it to see if it has possibilities for the average amateur fusioneer.

I have added a closeup image from the ad.......

George, please leave you post with the image up for reference in future. Carl has done a bit of good research on this and I would hate to uncouple from the image.....Thanks

Richard Hull

[Richard Hester]

I fairly recently picked up a SI13N boron lined tube on Epay. I suspect its of the proportional type, but I may be wrong.