Ludlum 2200 scaler + snm17 and 14

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Sarmad suseyn
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Ludlum 2200 scaler + snm17 and 14

Post by Sarmad suseyn » Tue Jun 16, 2020 10:54 am

Hi
I just got my self a new toy ludlum model 2200 scaler.
I just want to know the resistor that required for the snm-17 and snm -14. I already connected 10m ohm ,is it ok? Or i should use 100m ohm resistor? (10m×10 piece)
Any ideas? For the connecting the tubes to the scaler ?
And what is the best voltage for them ?
Thanks in advance
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Mark Rowley
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Re: Ludlum 2200 scaler + snm17 and 14

Post by Mark Rowley » Tue Jun 16, 2020 3:53 pm

Sarmad,
Many of us responded to you in this thread (viewtopic.php?f=13&t=13216) regarding neutron detection and you never answered back. The answers/suggestions/responses to your questions are still there.

As stated in other threads, the CHM17 (snm) is a Soviet 3He tube. LND type 3He tubes are good but the old Soviet versions are known to be extremely sensitive to electrical noise from a Fusor and in my opinion no suitable for such an environment. The CHM14 is a boron tube and not as susceptible to said noise and do quite well with a Fusor. If you intend on using the 17, you're really on your own as I dont believe anyone here has made one work in a Fusor environment. For non-electrical isotopic sources (Am/Be or Po/Be) they do fine.

Your 2220 is an older model and most definitely has different electronics than a later model or the 2221 that I run. I cant attest to it's compatibility with the CHM14. I'd recommend reading the entire thread that I linked including the responses given to your questions. It should be of some help.

Mark Rowley

Sarmad suseyn
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Re: Ludlum 2200 scaler + snm17 and 14

Post by Sarmad suseyn » Tue Jun 16, 2020 5:14 pm

Dear Mark Rowley
Till now trying to understand which answer you are waiting for?
And regarding the snm17 at least want to try with Am-Be source for now.
Best Regards

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Richard Hull
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Re: Ludlum 2200 scaler + snm17 and 14

Post by Richard Hull » Tue Jun 16, 2020 9:27 pm

I have always lusted after one of those Ludlum 2200s. Unfortunately, all the warranted working ones were too expensive for my tastes and the one or two others had the dreaded "unable to test" statement attached. You have a jewel there if it is fully functional! It is a virtual NIM bin in a box! Good luck with it and your neutron measuring adventure that lay ahead of you.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
Retired now...Doing only what I want and not what I should...every day is a saturday.

Sarmad suseyn
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Re: Ludlum 2200 scaler + snm17 and 14

Post by Sarmad suseyn » Tue Jun 16, 2020 9:53 pm

Thanks Richard
Got it from Ebay for the total of 924$
It came with probe 44-62
Calibrated from ludlum on 23.04.2020

Sarmad suseyn
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Re: Ludlum 2200 scaler + snm17 and 14

Post by Sarmad suseyn » Wed Jun 17, 2020 7:02 pm

Update:
I had success with the snm-14 tube with 1m ohm resistor
With 700v on ludlum 2200. With Am-Be source.
But till now no success with snm17
Tried with 10m , 50m , 100m resistors from 1000v to 2500v
Nothing. Any help😪😢

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