Cutting edge GM counter (1953)

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Mark Rowley
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Re: Cutting edge GM counter (1953)

Post by Mark Rowley »

Impressive! Doubt I'll progress to making my own circuit boards but who knows, retirement has been an interesting road so far.
I'm far from a purist when it comes to restorations, but I just cant gut a detector unless its a totally corroded/rusted mess. Like to the point where identification of components is impossible coupled with supporting hardware reduced to an oxide. And I do have a couple in that condition....hence the MCA module.

I'm with ya on the restoration price. I've done quite a few (radios included) with most over $300. Shipping can add $60+ to that as well.

Mark Rowley
Last edited by Mark Rowley on Tue Oct 15, 2019 2:25 pm, edited 1 time in total.
Roberto Ferrari
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Re: Cutting edge GM counter (1953)

Post by Roberto Ferrari »

Hi Mark

Electronics inside the main box is splitted, as you can see in this picture.
I am not in the mood to track the wires, etc.

Hi Richard
Your approach is great, but I stick to the conservative way, not to modify too much the original object.
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Mark Rowley
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Re: Cutting edge GM counter (1953)

Post by Mark Rowley »

Very similar Roberto. High probability the modules are the same.

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Roberto Ferrari
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Re: Cutting edge GM counter (1953)

Post by Roberto Ferrari »

Hi Mark

Being similar the models, I accept gladly your offer.
Please get in touch by PM.

Thanks!
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Mark Rowley
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Re: Cutting edge GM counter (1953)

Post by Mark Rowley »

-QSL-

Mark Rowley
Roberto Ferrari
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Re: Cutting edge GM counter (1953)

Post by Roberto Ferrari »

Hi Mark

Thanks a lot for that file.
Very similar design.
Now I will struggle for devoting some time to the restoration.
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Mark Rowley
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Re: Cutting edge GM counter (1953)

Post by Mark Rowley »

Just for fun I used a 6.5 decade old PRI 111 Scintillator to detect x-rays coming off the fusor. The 111 goes to full deflection on the 2.5mR scale as I ramp it up from 22 to 25.5kV.

https://www.youtube.com/watch?v=w1cHW6TrhTU

Mark Rowley
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Richard Hull
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Re: Cutting edge GM counter (1953)

Post by Richard Hull »

Quite normal near a fusor. I use a victoreen ion chamber detector and, as most here know, my view window points down to the concrete floor. I get about the same reading, (2-3 mr/hr) here when about 12 inches from the fusor body at 38kv. However, if I get the nose pointed in the narrow cone almost touching the window,1-inch away, I get 40mr/hr. At the controller work station, ~ 6 feet, I get about 0.5 mr/hr. from the fusor body and nothing from the cone. My permanently affixed camera, of course, takes the full 40mr/hr and some pixels are lost in the CCD from the 15 years fusor IV has been around.

I have some 100 mren dosimeters and three chargers and always wear one, but to date, they never move off zero as the blast is only present during 3 or 4, 5-minute runs over the two hours it takes to start and take data from the fusor. Based on the .5 mrem/hr ion meter reading with 20 minute total exposure at 6 feet that would register a total dose of 0.5/3 or less than 0.2mrem which is virtually no dose at all.

I took data for over 12 daily runs in a row prior to the HEAS event for a probable total absorbed dose of 12 X 0.2 or 2.4 mrem I rarely run the fusor more than twice yearly. The rest of the time it just collects dust and takes up space.

Put you 111's snout right at the naked window and take a reading and you will see why I point my window straight down into the floor. Will the 111 even read that high??

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
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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