Fusor Forums

Hi
Do any one have information about general electric boron lined neutron detector. I bought it for 90$ from ebay.
https://www.ebay.com/itm/194930183616?m ... media=COPY
Didn't test it yet.
Thanks in advance

This is the tube so common to the 1950's. They are great tubes made well by GE. However, (there is always a however), they are the devils own effort to bias properly. they operate at very low voltages for neutron detectors. Most come to heel between 650 - 900 volts. They will leap into simple GM tube action before they will detect neutrons. Then if you go too high in voltage they just detect neutrons + all gamma rays/x-rays. They have a rather narrow band of voltage where they stop acting like GM tubes and detect all radiation and where they start detecting gamma rays. You want to be in this narrow region of neutron detection and relative gamma and x-ray rejection.

You almost need a good pure neutron source to find that point. when biased properly these are great tubes. It is just that many folks do not possess a variable supply and a good preamp and scope needed to find the sweet spot for neutron detection.

I have discussed these in the FAQs.

I do not like to accept neutron club entries based on this tube unless the user can show it will not detect a real hot beta/gamma source.

Richard Hull

Thanks for the reply
When i test it i will submit the results. you are right regarding the voltage . Just found general electric data sheet for newer version of the detector. Attached. What i have only AmBe and RaBe neutron sources.

While this PDF is not the exact duplicate of what you have, but a more recent version, the data is intrinsically correct. The key verbiage by GE is....
"With the correct choice of electronics...."

This means that it is operated exactly like a 3He or BF3 tube, electronically, as it is a proportional tube. The important thing is, as with all proportional tubes, applying a correct bias and using a single channel amplifier to discriminate out the non-neutron pulse signals. This usually means the use of a scope and a good neutron only source in the presence of a hard gamma source.

As I noted above, this is a great tube, assuming it is in operating order and is electronically operated within its critical range.

Richard Hull