Neutropn source

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Rich Feldman
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Re: Neutron source

Post by Rich Feldman » Thu Jul 01, 2021 2:36 am

Yes, what Richard said about neutron sources that can be turned on and off with a switch.
And about government safety regulations for stewardship of strong radioisotope sources.

I learned there are similar rules for licensing and tracking of some ionizing radiation sources that are electric and switchable.
For example, x-ray generators for radiography.
I can lift with one hand a dental generator which, while energized, produces a flux of high-energy photons
equal to that from thousands of curies (kilograms of Ra-226) of radioisotope.

Am reminded of old field equipment for medical radiography using 60 keV gammas from Am-241 isotope sources.
Does anyone here know how the gamma activity of that isotope compares to its alpha activity?
I think It's because of gammas that we aren't supposed to sleep next to smoke detectors.
Some highly active 1960's-era Soviet smoke detectors use "plutonium" as alpha source, and become more hazardous as some Pu241 decays to Am241.
All models are wrong; some models are useful. -- George Box

John Futter
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Re: Neutropn source

Post by John Futter » Thu Jul 01, 2021 8:12 am

We use 8 giga Becquerel Am sources on our gamma backscatter gauges that we sell / hire to do tomography on wooden power poles and wooden bridges.
we are now starting to replace with 70kV x-ray sources running a couple of hundred microamps on the tube.

I know this as I designed the electronics

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The regulatory authorities much prefer the x-ray version as when its off its not still radiating

Yannick Verbelen
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Re: Neutropn source

Post by Yannick Verbelen » Thu Jul 01, 2021 11:26 am

Richard Hull wrote:
Wed Jun 30, 2021 10:46 pm
Fusors never put out the neutron numbers found in a permanent source. (Very weak source of neutrons and of extremely low duty cycle in doing so.)
Thank you for elaborating, Richard. I'm a bit confused by the quote above, though. The Am-241 activity in a typical smoke detector is about 30 kBq, so if you build an AmBe source with it, even if it has an efficiency of 100%, would the number of neutrons produced not also be limited to 30,000 n/s? Considering every alpha particle only produces a single neutron? Whereas with fusors you could reach 10^5 - 10^6 n/s.

Commenting on the X-ray source analogy, I read in a report a while ago that until the 1980s portable XRF analysers used in the metallurgy industry used Am-241 sources in the order of a few MBq as source of 59 keV gammas because the X-ray tube technology could not yet be made sufficiently compact for a portable device. But nowadays all commercial portable XRF analysers use miniature X-ray tubes. I had the chance to use one a few years ago, and the dose rate at the aperture was in excess of 100 mGy/h so relatively high.

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Richard Hull
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Re: Neutropn source

Post by Richard Hull » Thu Jul 01, 2021 6:00 pm

All alpha sources with Be are unbelievably inefficient with the very finest efficiency it is well below 10,000 alphas/sec from the radio-isotope of choice mixed in flawlessly with Be dust to yield 1neutron/sec. and probably not even that good! There is a lot of ideas that seem reasonable at first blush related to radiation physics that just will not happen. 9,999 alphas will just be slowed to the point of not having the energy to make a neutrons with only one hitting at full energy a Be atom to make that 1 neutron. Thus, any neutron source relying on alpha isotopes is really just a helium generator with an occasional neutron emission.

Such information as above requires reading and study to discover. Read, read,read....

Re: XRF....We have a local scrap yard and they use an XRF "gun" with a strong Am241 source in it to identifiy high Ni alloys and other valuable metals that come in as scrap. They had to send one of their people to a short training school to become their registered rad-safe/source security officer before they were allowed to purchase it.

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.

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Dennis P Brown
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Re: Neutropn source

Post by Dennis P Brown » Sat Jul 03, 2021 12:31 pm

This is a perfect example of doing a lot of wrong things here - not that I too haven't been guilty from time to time. I assume this thread maker now uses their full and proper name (not gonna really check - not that concerned.) Next, using block quote's is not to be done - this is being violated constantly so stop doing it, please. Next discussing very unrelated topics in an introduction thread! Please stop and start a new thread in the appropriate (or there about) proper topic area/section.

Following the rules isn't just being a good member/manners - it keeps this forum understandable and searchable. Thanks (and let us all stop answering in this introduction thread, maybe ;) )

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Site Admin
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Re: Neutropn source

Post by Paul_Schatzkin » Tue Jul 13, 2021 2:39 pm

theapower wrote:
Tue Apr 06, 2021 12:35 pm
I have been asked to submit my real name rather than the name under which originally registered (ThEA Power). This is:
John David Simnett
Ya know, we don't have a whole lot rules around here, but the ONE rule that has been rigorously enforced for like a decade now is: use your real name. Please change your registration accordingly. It's not like you didn't get clear indication of the policy when you signed up.

Some people. Jeezus.

Paul Schatzkin, aka "The Perfesser" – Founder and Host of
Author of The Boy Who Invented Television -
"Fusion is not 20 years in the future; it is 50 years in the past and we missed it."

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