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Ash Small

Sun Dec 02 2012, 09:40AM

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

If I remember correctly, the two reactions that occur in a fusor when using deuterium as fuel are as follows:

Fusors usually run at around 40kV, but fusion will occur at 20kV. The rate of fusion increases with voltage until the Oppenheimer-Phillips process starts, off the top of my head this starts around 2MeV, but I'd need to check this, it may be less.

Proud Mary

Sun Dec 02 2012, 10:07AM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

Andy wrote ...

What about isotopes, creating them. Smoke alarms have radioactive components. What would the limit be before it comes illegal.
I always thought they could use CCl to detect nuclear stuff on the other side off the world by neutrinos

Sealed sources of Am-241 in smoke detectors are exempt from regulation in the UK under the Radioactive Substances (Smoke Detectors) Exemption Order 1980 so long as they remain sealed and do not become radioactive waste. The exemption only applies while the sealed source is incorporated into a smoke detector, and ceases to apply if the sealed source is removed from the detector, or the sealed source is 'mutilated.' You can read the whole statutory instrument here:

Shrad

Sun Dec 02 2012, 10:19AM

Registered Member #3215 Joined: Sun Sept 19 2010, 08:42PM
Location:
Posts: 780

same for X-ray and laser devices, they have to be certified against IEC regulations, and the operator also has to have licenses to use and sometimes even transport them

it has a variety of forms from the dental x-ray girl who takes your dental shots, to the research associates working with high power devices at universities

but most of the times this is not followed in other fields than food and drugs or medical and industrial fields, and someone operating a laser in a small event like a party has nothing to fear... even if he has a modified chinese crap with stepper motors and no IR filter and blinds people

the same for TEA lasers or anything high voltage and spark related... it produces UV in enormous amounts, and it is ionizing to a point

it's more a matter of good intelligence than regulations, when you are not doing something harmful to the society willingly

Ash Small wrote ...

Andy wrote ...

What would the limit be before it comes illegal.

If it's designed to produce ionising radiation it's illegal without a licence.

(As I mentioned earlier, the 'fusioneers' get around it by saying 'it's not designed to produce neutrons, they are a by-product of fusion')

Proud Mary

Sun Dec 02 2012, 11:04AM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

Shrad wrote ...

same for X-ray and laser devices, they have to be certified against IEC regulations, and the operator also has to have licenses to use and sometimes even transport them

it has a variety of forms from the dental x-ray girl who takes your dental shots, to the research associates working with high power devices at universities

but most of the times this is not followed in other fields than food and drugs or medical and industrial fields, and someone operating a laser in a small event like a party has nothing to fear... even if he has a modified chinese crap with stepper motors and no IR filter and blinds people

the same for TEA lasers or anything high voltage and spark related... it produces UV in enormous amounts, and it is ionizing to a point

it's more a matter of good intelligence than regulations, when you are not doing something harmful to the society willingly

Ash Small wrote ...

Andy wrote ...

What would the limit be before it comes illegal.

One UK member of 4HV was visited by a Radiation Protection Officer together with a Health & Safety official to inspect his x-ray equipment. They satisfied themselves that his shielding and other safety precautions were of an adequate professional standard, and that the x-ray device was not in a domestic premises etc, and he was allowed to continue. They let him know that they were aware of his online postings about his x-ray experiments, and asked him not to post further 'how to do its' on the web, as a result of which he has removed detailed material from his website.

Perhaps in other countries and jurisdictions you can ignore regulations and official investigations like these, but in the UK it would be unwise, and potentially very costly.

Conundrum

Sun Dec 02 2012, 05:27PM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4059

Really? Not heard about this.
Also, it seems that even vacuum pumps can be classed as "hazardous components" due to the oil used and risk of implosion if the chamber connected to them is not up to scratch.

Andy

Mon Dec 03 2012, 04:57AM

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

Would a xray at the pair production(1.022 MeV) voltage produce enough energy to turn T into He.
Just being tweaking a marx setup to reach 1.022 and fire into tungsten, with the xrays sent into T, would that make much fusion

Ash Small

Mon Dec 03 2012, 06:04PM

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

Conundrum wrote ...

Really? Not heard about this.
Also, it seems that even vacuum pumps can be classed as "hazardous components" due to the oil used and risk of implosion if the chamber connected to them is not up to scratch.

plazmatron wrote ...

Bored Chemist wrote ...

HSE is the enforcing authority for the health and safety at work etc act.
If you are not at work, they don't care what you do.
I'm not sure how they view students. (probably with contempt- like the rest of us)

They will make an exception where ionising radiation is concerned.

Steve McConner wrote ...

plazmatron wrote ...

Sound like the voice of experience? It is.

Does this have anything to do with the disappearance of the hobby X-ray info from your site? :-/

Well spotted, indeed it does. It was suggested, that having "how-to's" on there was not in my best interests.
So in the interests of staying on the right footing I removed them. Likewise, the "about me" page was re written, since "they" didn't want the inexperienced copying it.

Some bits will make it back. Obviously details of detectors is perfectly OK, as are Scientific/Technical papers etc. But anything that implies unsafe practices should be avoided.

Ultimately, its not really a bad thing, a little professionalism is needed in this particular area, and my site will benefit from being a little less amateurish.

Les

plazmatron wrote ...

Steve McConner wrote ...

OK, so if you don't mind sharing, who were "they", the HSE? And how did they get onto you?

I think technically speaking, your use of X-rays would be classed as work, since you sell prints (very nice ones at that

)

They were indeed the HSE. Seemingly someone reported my activities to the local council, who informed them. Not that I have ever been secretive about what I do. In fact a couple of years back, my "happy" neighbour threatened to go to the Police about my activities (that she claimed were illegal), so on the advice of Proud Mary, I took a list of equipment and chemicals along to the Police, The local Pharmacist and my GP.

It would seem that openness is the way to go with these things.

Thanks for your compliment! I do sell prints, but not really often. The HSE accepted that what I do is a hobby, but stated they made an exception as it involves the use of ionising radiation.

The HSE's position on the whole thing is that they do not encourage people to build or use x-ray machines at home. Nor is that fact that mine passed their inspection, any kind of permission for anyone (including me) to do as they please.
They were quite clear that in this case there was no concern with my current activities. Which is to my mind a carefully worded way of saying "if you build another one in the future, it had better be as compliant too",but at the same time they are saying "we are not encouraging you to build one either".

As I alluded in my previous post, the whole thing is self contained, and is compliant above and beyond the recommendations set out in the IRR, and I can assure everyone here, that if it had not been, the HSE could and would, have had it removed, and probably at my cost.

It should be noted, that should you fall foul of any criminal injury proceedings (ie you irradiated a person or animal), the HSE will not defend you, even if they had inspected your setup. Like a vehicle MOT they are saying "on the day we inspected it...."

Their recommendations were to remove the references on my site to any x-ray activity that could be construed as careless or reckless (for example mentioning the fact I radiographed my fingers when I was a kid!).
For now, I have taken down the entire section. As I said, some bits will re-appear after they have been extensively rewritten, however there will be, no "instructions" or ""how to's" on this particular subject, which really, thinking about it, is very wise anyway.

So my stance on the matter has pretty much ended up like theirs. I can not condone anyone building one, nor will I give any instructions on how to do it. However, at the risk of being a nag, you can expect me to point out safety issues, and mistakes, as far as this forum goes.

It is one of those hobbies, that must be done by the book if we expect to continue doing it, but even that is no guarantee. The mere mention of the word "Radiation" is enough to instill fear in most people, and the subject will always be a political hot potato.

Les

Link:

Proud Mary

Mon Dec 03 2012, 07:05PM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

Andy wrote ...

Would a xray at the pair production(1.022 MeV) voltage produce enough energy to turn T into He.
Just being tweaking a marx setup to reach 1.022 and fire into tungsten, with the xrays sent into T, would that make much fusion

Prior approval for the use of accelerators achieving energy levels exceeding 1 MeV is required under the Ionising Radiation Regulations 1999 in the United Kingdom, and by parallel legislation throughout the European Union.

Ionising Radiations Regulations 1999
Prior authorisation for the use of accelerators (other than electron microscopes)

1. For the purposes of regulation 5(2) of the Ionising Radiations Regulations 1999, the Health and Safety Executive (HSE) hereby authorises the type of practice referred to in paragraph 3 subject to any such practice being carried out in accordance with the conditions hereby approved by HSE as set out in paragraph 4.

2. Notwithstanding the prior authorisation given in paragraph 1, radiation employers must comply with all other relevant requirements of these Regulations, including notifying HSE of their intention to work with radiation in accordance with regulation 6.

3. The type of practice referred to in paragraph 1 is:
The use of accelerators (other than electron microscopes).

NB: The scope covers all uses of accelerators (other than electron microscopes), including medical and veterinary purposes (an accelerator is an apparatus or installation in which particles are accelerated and which emits ionising radiation with an energy higher than 1 MeV).

4. The conditions referred to in paragraph 1 are as follows. The radiation employer shall:

4.1 as part of satisfying the general requirement in regulation 8 of the Ionising Radiations Regulations 1999 to keep exposure as low as reasonably practicable, take specific steps before starting the work to provide engineering controls, design features, safety devices and warning devices which include at least the following:

where the work is to be carried out in a room, purpose made structure, other enclosure or a cabinet:
adequate shielding as far as reasonably practicable; and
interlocks or trapped key systems or other appropriate safety devices in order to prevent access to high dose rate areas (eg in which employed persons could receive an effective dose greater than 20 mSv or an equivalent dose in excess of a dose limit within several minutes when radiation emission is underway). The control system for such safety devices should comply with paragraph 4.4;
in other cases, adequate local shielding as far as reasonably practicable and, in the case of site radiography, a suitable system for ensuring that:
persons other than those directly involved in the exposure are excluded from the area by means of a barrier or other suitable means;
where employees of another employer may be present in the same workplace, there is co-operation and co-ordination with the other employer(s) for the purposes of restricting access to the controlled area;
warning notices are displayed at the perimeter of the controlled area; and
radiation levels are monitored to establish that controlled areas have been properly designated;
suitable means to minimise exposure so far as is reasonably practicable from substances that have been activated by the accelerator;
a suitable assessment of the hazards arising from the production of adventitious radiation;
where there is a risk of significant exposure arising from unauthorised or malicious operation, equipment which has been fitted with locking-off arrangements to prevent its uncontrolled use;
initiation of exposures under key control, or some equally effective means, so as to prevent unintended or accidental emission of a radiation beam; and
suitable warning devices which indicate when the accelerator is preparing to produce radiation and give a signal when the radiation is about to be produced and a distinguishable signal when the emission is underway, unless this is impracticable;

4.2 arrange for adequate and suitable personal protective equipment to be provided where appropriate;

4.3 arrange for suitable maintenance and testing schedules for the control measures selected; and

4.4 provide safety devices, as referred to in 4.1(a), which should be configured so that the control system will ensure that an exposure:

cannot commence while any relevant access door, access hatch, cover or appropriate barrier is open, or safety device is triggered;
is interrupted if the access door, access hatch, cover or barrier is opened; and
does not re-commence on the mere act of closing a door, access hatch, cover or barrier.

Signed

Margaret Clare
A person approved by the Health and Safety Executive to perform the functions under regulation 6(2) of the Ionising Radiations Regulations 1999.

Andy

Wed Dec 05 2012, 01:37AM

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

If I get to those voltage.... cheers
@ash small
What makes the D combine to make T in fusion, like how much energy or speed, does it need to by squashed. Would putting it in a sphere with a positive charge, how much charge before they get squashed enough to fuse, or I'm I still off track. cheers

Ash Small

Wed Dec 05 2012, 09:35AM

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

Andy wrote ...

If I get to those voltage.... cheers
@ash small
What makes the D combine to make T in fusion, like how much energy or speed, does it need to by squashed. Would putting it in a sphere with a positive charge, how much charge before they get squashed enough to fuse, or I'm I still off track. cheers

The fusor basically creates a 'sphere with a positive charge'.

You need to read up on 'fusion cross-section'.

The 'fusion cross-section' is basically the probability that two ions will fuse when colliding at a specific energy, ie if two D+ ions, in a fusor at 20kV, ie they each have an energy of 20keV, so their collision energy totals 40keV.

Not all collisions are 'head on', etc.

It does get quite complicated, ie the current school of thought is that most 'fusion events' in a fusor are between fast ions and slow moving neutrals, because there is more chance of a 'head on' collision between a fast ion and a slow moving neutral.

Basically, the fusion cross-section increases with voltage (EDIT: until the Oppenheimer-Phillips process starts at around 2MeV). I also showed once that, to a point, it increases as a function of 1/2 I^2, although other factors are also involved.

Hope this helps.

EDIT: Found this graph showing the cross-section for Oppenheimer-Phillips process for Deuterium, showing that the process starts at just over 2MeV.

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