Fusor Forums

Hi all
Im trying to build a neutron detector tube for experimental use
This tube can be filled with different gases easily.
Check the pictures, just finished it today. Ofcourse im using a vacuum pump first then im going to fill the gas. Any ideas for the gas , happy to try . There is cathode and anode parts.
Thanks

Welcome, and I'll go look for your personal introduction posted in the proper place. It may serve as evidence that you are not a forum troll.

Looks like a good start on your DIY detector tube. Can't really see what you've got for high voltage insulated center wire.

How about if you practice detecting gamma rays first ? You probably know that to be specific for neutrons, tube needs a fill gas with special nuclear properties, like helium-3 or boron-10 trifluoride.

Gamma rays for testing need enough energy to penetrate your metal tube, or a window at the end of the tube.
I guess any kind of ray from a radioactive source inside the detector tube ought to be countable, when you get the gas and electricity details right.

Do you understand the operating theory of ionization chambers, proportional tubes, and GM tubes?
Ion chambers, like those found in smoke detectors, are simplest. The most common fill gas is air at atmospheric pressure. But to get a reading, you need to measure very small currents (picoamps) or have a dangerously intense source of radiation. Latter could be a x-ray tube, but at those photon energies your copper tube is practically opaque.

Is that a bicycle/car style pressure inlet plug? If you use a pressurized gas it will leak down over time. 3He which is best for thermal neutron detection is either not available or vastly too expensive. The highly toxic Boron Trifluoride is just not commonly offered for sale to regular folks. At any rate the tire fill fitting will not work.

Richard Hull

Hi thanks for replays
This a fridge charge valve , it can hold high pressure
Yes i understand the theory. Just i want to try something new
Maybe i will get something.
Im using a high voltage adjustable Module from 100 v to 1300v
Its stable and works fine .
https://rover.ebay.com/rover/0/0/0?mpre ... 894388541
1 -I have a x-ray tube . I can test on high penetration.
2- i have more than 200 smoke detector americium and a beryllium chunk. As neutron source.
If you want Bt gas here you go
https://www.entegris.com/shop/en/USD/p ... rifluoride
How to discover something if we dont test and try

Please update your profile using your real name. Tnx

Mark Rowley

Sam,

Well done, 10/10 for attempting to roll your own tube. Hope it works on the first attempt, but if not try try again..

What are you using as an anode wire inside, how thick is it and how did you prepared it?

One day I might try doing this myself.

Steven

I admire your drive, but drive must be tempered by reality. I read your link to the source for isotope enriched boron trifluoride. That this material is commercially available is not a surprise, but I would be willing to bet:
1. It will boggle your mind what this material sells for, and
2. Even if you were willing to pay the price, it is highly unlikely that they would sell it to you.
I apologize for raining on your parade.

Dan, I was getting ready to get back to him and rain just as hard on his parade. Big ideas even fabulous ones have continuous rain storms and even hurricanes that sink the entire ship....In port!! Anyone can find anything for sale on the internet. How much will it cost?? Can they afford it??? Do they force you to buy a specific minimal amount that is enough to do 1200 projects that you have in mind? Is it the old saw of if you aren't going to by 10lbs, don't bother to ask us for 1/4 ounce..."We don't sell in small lots"

Big companies that handle hazardous and dangerous materials, as we know, just do not ship or sell lethal materials to the average Joe. They have a legal department designed to immediately stop possible libelous claims against them in some horrid tragedy due to misused materials that they supply which results in injury or deaths. They have built in dead stops prior to selling....What is your company? What are the federal and state tax numbers for your company? Are you listed with Dunn and Bradstreet? What does your company do with BF3? Give us your accounting department's fax number and we will send over our credit application forms to fill out and we will review them and establish and assign your company a formal account number with us.

Let 'em learn the hard way. BF3, 3He, and deuterium are not hardware store materials where all you need is to find a seller on the internet, lay down a platinum credit card, and have the material winging its way to your little bungalow or apartment's address.

Richard Hull

Dear Richard Hull
I want to know who told you im trying with BF Gas?
If you noticed i said to try with different types of gases.
Im going to test every gas i can put my hands on.
Please read this:
https://www.google.com/url?sa=t&source= ... 7J2GqeqSZn
Don't be so negative. I can make another tube and send it to you
If you want to try.
Thanks

Sam
the problem as I see it is the tubes respond better to gammas/x-rays than neutrons
they used a source that is neutron rich gamma poor in the experiment and sight problems with gammas clouding the results -needing pulse height analysis to negate the gammas
better neutron detectors that amateurs can make are the ones based on silver activation like the Hornyak.
I also note that the article you reference seems to suggest a gridded detector aka Friis grid not a modified geiger tube assembly ie the grids are very close together with width and not a wire down the center
Note:from the paper that Helium is 5 times better as the detector gas over argon-- so maybe hydrogen might be even better ie light gasses are better

But you are experimenting --well done

This my first list of trial gases by next week starting
This list of very easy to find gases

Here is my list of gases for first trial:
1. Oxygen (O2)
2. Nitrogen (N2)
3. Helium (He)
4. Argon (Ar):
5. Carbon dioxide (CO2)
6. Acetylene (C2H2)
7. Propane (C3H8)
8. Butane (C4H10)
9. Nitrous oxide (N2O)
10. Cl gas
11. Sulfur dioxide
12. Neon
13. Hydrogen
14. Hexafluoroethane
15. trifluoroethane
. Still working on the list

Yay for experimenting.

It's important to restrict some variables, or let the sequence be guided by on-going results.
To test every gas in your list at 10 different absolute pressures, and 10 different voltages,
even with a single radioisotope source and moderator configuration, would be 1500 runs.
We await your first counts of any kind of radiation.

For the real easy to find gases, don't forget:
* air
* natural gas

Beware that ordinary commercial propane (LP gas) and butane are hydrocarbon mixtures with specified BP ranges, plus odorant. I think refrigerant grade hydrocarbons (R-290 and R-600a) are "technically pure" chemicals. In recent news, somebody blew up their house while performing a botanical extraction using butane, either n- or iso.