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Creating a neutron source

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Andy

Thu Dec 06 2012, 04:27AM

Registered Member #4266 Joined: Fri Dec 16 2011, 03:15AM
Location:
Posts: 874

Cheers Ash Small, it cleared things up.

dex

Thu Dec 06 2012, 12:22PM

Registered Member #2566 Joined: Wed Dec 23 2009, 05:52PM
Location:
Posts: 147

Andy wrote ...

Would the below picture work for a neutron source using electron capture, if it was at atmosphere pressure and over 140kv for tungsten(blue)?
What would be the mean free path of a neutron at atmosphere pressure and 100kev.

Cheers

1354328403 4266 FT0 Electron

fortunately,it would not

Ash Small

Thu Dec 06 2012, 02:51PM

Registered Member #3414 Joined: Sun Nov 14 2010, 05:05PM
Location: UK
Posts: 4245

I think, with hindsight, that your first post related to spallation, which will occur when firing protons into tungsten, tantalum, etc, but you are talking in the range of ~80MeV, if I remember correctly. At these energies neutrons will be spallated, but it will still require an ultra high vacuum, as far as I'm aware.

EDIT: CORRECTION.....THE ISIS SPALLATION SOURCE (ON WHICH I WORKED, AND HAVE SOME PHOTO'S OF THE SECOND TARGET STATION SOMEWHERE, AND WILL POST SOME IF ANYONE IS INTERESTED) FIRES A BEAM OF PROTONS AT 800MeV. (I WAS ONLY A FACTOR OF TEN OUT

)

Bored Chemist

Thu Dec 06 2012, 09:22PM

Registered Member #193 Joined: Fri Feb 17 2006, 07:04AM
Location: sheffield
Posts: 1022

HSE has no jurisdiction for activity undertaken at home as a hobby.
In particular, the ionising radiation regs say define work as "(3) For the purposes of these Regulations and Part I of the Health and Safety at Work etc. Act 1974â€”

(a)the word â€œworkâ€ shall be extended to include any instruction or training which a person undergoes as a trainee and the meaning of â€œat workâ€ shall be extended accordingly; and
(b)a trainee shall, while he is undergoing instruction or training in respect of work with ionising radiation, be treated as the employee of the person whose undertaking (whether for profit or not) is providing that instruction or training and that person shall be treated as the employer of that trainee except that the duties to the trainee imposed upon the person providing instruction or training shall only extend to matters under the control of that person."

and practice as "â€œpracticeâ€ means work involvingâ€”
(a)the production, processing, handling, use, holding, storage, transport or disposal of radioactive substances; or
(b)the operation of any electrical equipment emitting ionising radiation and containing components operating at a potential difference of more than 5kV,
which can increase the exposure of individuals to radiation from an artificial source, or from a radioactive substance containing naturally occurring radionuclides which are processed for their radioactive, fissile or fertile properties;"

and the range of applicability is "3.â€”(1) Subject to the provisions of this regulation and to regulation 6(1), these Regulations shall apply toâ€”

(a)any practice;
(b)any work (other than a practice) carried out in an atmosphere containing radon 222 gas at a concentration in air, averaged over any 24 hour period, exceeding 400 Bq mâˆ’3 except where the concentration of the short-lived daughters of radon 222 in air averaged over any 8 hour working period does not exceed 6.24 Ã— 10âˆ’7Jmâˆ’3 and
(c)any work (other than work referred to in sub-paragraphs (a) and (b) above) with any radioactive substance containing naturally occurring radionuclides."

This follows from their position as the enforcing authority for "the health and safety at work &c act".
Since we are not at work, it's not their field.
(The &c. bit doesn't apply in this case).

You could get into trouble as a suspected terrorist or if you actually harmed anyone but the HSE aren't the people to worry about.

Ash Small

Thu Dec 06 2012, 11:39PM

Registered Member #3414 Joined: Sun Nov 14 2010, 05:05PM
Location: UK
Posts: 4245

Bored Chemist wrote ...

HSE has no jurisdiction for activity undertaken at home as a hobby.
In particular, the ionising radiation regs say define work as "(3) For the purposes of these Regulations and Part I of the Health and Safety at Work etc. Act 1974â€”
.
.
.
You could get into trouble as a suspected terrorist or if you actually harmed anyone but the HSE aren't the people to worry about.

I'm inclined to agree with you, BC. The 'threats' made against a member of our community have not been tested in court.

Should we, ie 'concerned UK members of this community', offer our support to the victim of these 'threats' in any ensuing court case that 'may' arise, re. 'harassment by the HSE'?

(I think it's unlikely that the individual that was 'threatened' wishes to take this matter any further, as he has taken down the 'how to's' from his website, so this is probably a hypothetical question, but WTF.....)

EDIT: I wish to emphasise that the apparatus in question not only complied with, but exceeded ALL the required safety standards, etc.

EDIT EDIT: If people are forced to take down information from their websites that explain how to do this safely, others may injure themselves (or others) as a consequence of the HSE's actions.

Andy

Wed Dec 12 2012, 09:51AM

Registered Member #4266 Joined: Fri Dec 16 2011, 03:15AM
Location:
Posts: 874

Would this work as a neutron source. What type of amps do you think I'll be looking at.

Ash Small

Wed Dec 12 2012, 01:20PM

Registered Member #3414 Joined: Sun Nov 14 2010, 05:05PM
Location: UK
Posts: 4245

Andy wrote ...

Would this work as a neutron source. What type of amps do you think I'll be looking at.

I think the answer to your question is 'maybe'.

You 'may' be better off applying AC to the two electrodes, rather than DC, but it 'could' work with DC.

I assume, from your drawing, that you are also planning to implement ECR (electron cyclotron resonance), although it may be that you wish to implement what I assume might be called 'deuteron cyclotron resonance' (I'm guessing here), whether this would induce collisions between deuterons, I'm not sure, as they would all be travelling in the same spiral trajectory

You'd need to get the deuterons up to ~20-40 keV, I'd assume, in order to get any fusion, even then I'm not sure you'd get many collisions with sufficient energy, but it seems probable that you might, as collisions will be taking place, resulting in deuterons following different trajectories.

As far as current is concerned, I think we'd need a lot more information about the proposed setup before we could answer that, it would depend on deuterium feed rates, etc.

I also ought to re-iterate that any apparatus designed to produce neutrons requires a license. There is also the question of neutron detection/monitoring, not to mention shielding (from neutrons and X-rays)

(Interesting concept, though)

EDIT: Actually, thinking about it, the 'cyclotron resonance' will require AC (RF or microwave frequencies) to work at all

Andy

Thu Dec 13 2012, 12:35AM

Registered Member #4266 Joined: Fri Dec 16 2011, 03:15AM
Location:
Posts: 874

Cheers, I'll be getting a survey meter ,vacuum pump and license when i've got some spare cash,
This is the formula I'm using
B = unI
permeability =1
Amps =10000
number of turns =10
distance =0.01
amp turns =10000000
Tesla =40000

and
F = Amps*Length*B
Amps 50000
distance 0.01
Tesla 40000

Force newtons/meter 20,000,000

Are these the right formulas to use in these situation, what would I be missing?
I'm trying to squash the arc, with the coil current going clockwise and the spark field going counter clockwise.

Made some caps to use, they should be 0.0239uF, wired up to the nst, makes white arcs, that are damn loud :), should get 7357amps for 2.39058e-8sec

Ash Small

Thu Dec 13 2012, 01:43AM

Registered Member #3414 Joined: Sun Nov 14 2010, 05:05PM
Location: UK
Posts: 4245

I'm not sure I've fully understood your diagram.

I assumed the magnets were there to facilitate 'cyclotron resonance', which, I think, will require microwave frequencies unless you use 'very expensive' magnets, in which case you 'may' get away with RF frequencies.

If I've missed the point, and this is maybe some form of 'Z pinch' system, you may need someone else to advise you. (It's a few years since I read up on Z pinch, but I do remember it involves very high currents).

It would help if you supply some more information, maybe a more detailed schematic, with some more figures.

(I'm only just 'getting my head round' the maths for cyclotron resonance myself, for a project I'm working on.)

Andy

Thu Dec 13 2012, 02:20AM

Registered Member #4266 Joined: Fri Dec 16 2011, 03:15AM
Location:
Posts: 874

If I've missed the point, and this is maybe some form of 'Z pinch' system, you may need someone else to advise you. (It's a few years since I read up on Z pinch, but I do remember it involves very high currents).

That was the idea, but I think they send the current through multi thin wires

I don't know of any more information to add

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