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Author Topic: do radioactive sources produce electricity?  (Read 3250 times)

Offline sorin cezar

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do radioactive sources produce electricity?
« on: 28/10/2013 14:18:54 »
Radioactive source - Electric charge displacement and definition of electric current


For the experiment the most common sources to be used are those of alpha and beta radiation; or a proton source for those who have one in their laboratory.
With any of these sources an experiment setup like in fig 1 is formed. In few words, the radioactive source generates electric charges (electrons or positive charges). These charges are directed on a charge collector (metallic foil around the radioactive source). From this collector, they pass through a circuit and after that are discharged at a null point (Earth connection).
According to actual electromagnetism, these radioactive source should produce a ,,real” electric current. The experiment was performed only with a beta radioactive source which emits electrons (secondary gamma radiation is not relevant for the experiment).
So, a beta source is surrounded by a box of metal conductor layer able to catch all emitted electrons and this is further connected to an electrolytic cell. The other electrode of the electrolytic cell is connected to a null point (Earth or a water pipe).

radioactive-source-charge-movement01

Figure 1 Charge displacement and electric current
As far in my experiments a small source of beta radiation was used, we have to use the same special microelectrodes chambers for electrolysis as described in Cathode ray tube experiment.
In our experiment acidulate (H2SO4) water solution is used in electrolytic cell. The water electrolysis was used in order to have a comparison between volume of gas released at anode and cathode. As far the volume of gas released is small and the time of experiment is long, I have used this chemical process in order to avoid a bias due to a possible gas release coming from the existent gas dissolved in solution. In case of another cell composition, when gas is released only at one electrode there are necessary some preliminary steps (degassing), and a more careful interpretation.
Having in mind the size of supposed ,,current” produced by a CRT, and consequently the volume of gas released at electrodes, some adjustments are necessary for a successful experiment.
The electrodes, made by platinum metal are gloved in two pipettes parts and sealed in flame. As is observed (fig. 2) around electrodes a space with a volume of about 0,1 ml is formed. Before experiment starting, using micropipettes these chambers are filled with acidulated water coming from electrolytic cell. These filled electrodes are introduced in an electrolytic cell with care in order to avoid a gas intrusion into electrode chamber. If a process of electrolysis takes place, the released gas will go up in the chamber and will push the liquid down. In order to be more evident this fluid displacement, in water a small quantity of colorant or a chemical indicator is added (in our example rot phenol). 
The accumulation of gas is cumulative for long time (the chamber is well sealed), even the current will be on micro ampere size.

A 60Co TELETHERAPY source with actual characteristic 400 Tbq (~10,8 kCi)  is used in the experiment.

As is well known 1 Ci = is equivalent with   3,7 x 10exp(10)  desintegrations per second and this means our source will emit a number of electrons equal with:

N = 10800x3,7 x 10exp(10)  =  0,37 x 10exp(15) electrons  per second

The total charge generated by this source in a second:

Q = N*e =  0,37 x 10exp(15)x1,6 x 10 exp(-19) = 0,59 x 10exp(-4) C=59 microC

In a day with the up presented setup, through electrolytic cell a total charge equal of:

Q` (day) = Qx24x3600 =5,09 C 

So it is supposed that a common radioactive source used in Cancer therapy has to generate similar effects like an electric current of 5,09C.

The time for experiment was an entire weekend and no gas was observed in the electrodes chambers.

The entire charge passing through electrolytic cell was about 13 C.

By comparison two chemical batteries (1,5V) connected in series for 5 minutes, gave a current of 0,89 mA and in electrodes chamber both hydrogen and oxygen are produced as in fig. 2.

radioactive-source-charge-movement02

Figure 2 Minielectrodes and detail of gas release after few minutes of electrolysis with a chemical source

As is observed, at one electrode a double volume (hydrogen) is released, in comparison with the other electrode (oxygen).

In a time of 300 s and with an intensity of 0,89  mA, through circuit passes a charge equal with:

Q=I*t = 0,89x10(-3)x300 =2,4 C

As is observed, a charge less then 2,4 C is more then enough to observe the effects of an electric current.
How is this experiment interpreted in electrodynamic?
« Last Edit: 01/11/2013 22:17:48 by chris »


 

Offline Bored chemist

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Firstly, so what?
There's nothing new there, it's just textbook physics.

On the other hand, it ignores some practicalities.
For example radiolysis due to the gamma rays would also generate H2 and O2 in the water unless the cables were quite long.
The radiation would also ensure that the air was a fair conductor of electricity so a lot of the charge would leak back.
 

Offline sorin cezar

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Please give me a single reference about this topic ...if it is only textbook physics

It is the first time when I hear that gamma rays can travel through metallic wires...
Of course gamma rays can decompose a lot of substances including water when they come into contact with it .

I covered the nuclear source with metalic foil, so even there is a  loss of electrons energy in air or other secondary ionization, the path is short so they have enough energy to arrive at the metallic foil...
In other case I can suppose that a treatment with such device is uselless because the air between source and human body act as a ,,particle screen"
In case you have to target a inside body organ the situation will be worse...I will need a nuclear bomb probably to arrive at the target...


 
 

Offline Bored chemist

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"Please give me a single reference about this topic ...if it is only textbook physics"
Which bits do you think are different from textbook science?
"It is the first time when I hear that gamma rays can travel through metallic wires"
Nobody said they did.
"Of course gamma rays can decompose a lot of substances including water when they come into contact with it . "
And you don't seem to understand how that is a problem.


"In other case I can suppose that a treatment with such device is uselless because the air between source and human body act as a ,,particle screen" "
http://en.wikipedia.org/wiki/Straw_man
 

Offline alancalverd

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Several points arise. First off, a Co60 therapy source won't provide much beta radiation. The Co60 - Ni60beta decay releases electrons of about 300 keV energy, nearly all of which will be absorbed in the rest of the source and capsule. Pretty much all that comes out will be bremsstrahlung and gamma radiation. If you want to generate useful charge from a radioactive source you would do better with a thin, flat sample of something like Sr90.

Second, 400 TBq is a lot more active than any normal teletherapy source. We normally use about 400 MBq. No need to convert to curies as 1Bq = 1 disintegration/second.

Third, you do claim to have remarkably easy access to radioactive material for one as ignorant as you seem to be of the subject. If you really do have a naked teletherapy source, I strongly advise you to seek medical attention, and if not, to at least engage the services of a competent health physicist before contemplating playing with such toys.   
 

Offline sorin cezar

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Several points arise. First off, a Co60 therapy source won't provide much beta radiation. The Co60 - Ni60beta decay releases electrons of about 300 keV energy, nearly all of which will be absorbed in the rest of the source and capsule. Pretty much all that comes out will be bremsstrahlung and gamma radiation. If you want to generate useful charge from a radioactive source you would do better with a thin, flat sample of something like Sr90.

Second, 400 TBq is a lot more active than any normal teletherapy source. We normally use about 400 MBq. No need to convert to curies as 1Bq = 1 disintegration/second.

Third, you do claim to have remarkably easy access to radioactive material for one as ignorant as you seem to be of the subject. If you really do have a naked teletherapy source, I strongly advise you to seek medical attention, and if not, to at least engage the services of a competent health physicist before contemplating playing with such toys.   

Your arguments cancel each other...
So 60Co electrons beam  is so faint that is absorbed into capsule, thin air , etc ...
And even a lower radiation source is used for (400 MBq) cancer treatment....
Probably the modern cancer treaments instruments are a kind of placebo instruments and you have to pay expensive for this ...
I have seen even sources at 500 TBq .. so ...

I have enough technikal skills aquired during years of certified studies in order to deal either with radioactive or stable isotopes ....
Thanks for your care ....I did not stay near the experiment all the weekend as you immagine .....
Do not worry about me .. I will not have the destiny of Marie Curie, but neither of Boltzman ......
 
« Last Edit: 31/10/2013 14:08:43 by sorin cezar »
 

Offline Bored chemist

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You seem to be making the same strawman argument again.
Please stop.

The electrons (and the charge they carry) are stopped rather easily by air or anything else.
The gamma rays are used medically.

Do you not understand that?
 

Offline alancalverd

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My apologies! 400TBq is entirely normal for teletherapy. Must have been late at night - just as well I wasn't on duty! But even so the beta yield from a teletherapy source is pretty negligible.

Boltzmann committed suicide - surely the most desirable death of all, but I wouldn't recommend suicide by radiolysis. 
« Last Edit: 31/10/2013 21:43:10 by alancalverd »
 

Offline Bored chemist

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Anyone can make mistakes like that.
However, 400TBq of 60Co is still a very dangerous source and I'm worried that someone might let this guy play with it. He clearly has more confidence than ability.
I don't see him following in Mme Curie's footsteps either.
Anyone taking odds for him getting two Nobel prizes?

Do you think it might be this?
http://en.wikipedia.org/wiki/Dunning%E2%80%93Kruger_effect

 

Offline alancalverd

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Anyone can, but I really shouldn't - this is the sort of error that kills patients.

Anyway, given that the doserate from a teletherapy source is in the order of 1 - 2 gray/minute at 1 meter, and a lethal dose is about 5 gray, I do hope our friend has some remote handling device for it. Otherwise he's on course for a Darwin if not a Nobel.

I thought the Dunning-Kruger bug was only carried by government health and safety inspectors, though it is known to be infectious.
 

Offline Bored chemist

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Anyone can, but I really shouldn't - this is the sort of error that kills patients.

Anyway, given that the doserate from a teletherapy source is in the order of 1 - 2 gray/minute at 1 meter, and a lethal dose is about 5 gray, I do hope our friend has some remote handling device for it. Otherwise he's on course for a Darwin if not a Nobel.

I thought the Dunning-Kruger bug was only carried by government health and safety inspectors, though it is known to be infectious.

It's just as well I'm a government H+S person (not actually an inspector, but...) with a sense of humour isn't it.

My guess would be that you pay a bit more attention at work then when posting a reply to nonsense on the web.
 

Offline alancalverd

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Re: do radioactive sources produce electricity?
« Reply #11 on: 01/11/2013 23:19:23 »
Quote
It's just as well I'm a government H+S person (not actually an inspector, but...) with a sense of humour isn't it.

You probably know the moron and assistant moron I'm referring to. Real Dunning-Kruger archetypes, and a standing joke among professionals.
 

Offline sorin cezar

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Re: do radioactive sources produce electricity?
« Reply #12 on: 05/11/2013 10:23:55 »
And finally affter you get convinced about the radioactive source .. maybe you will get convice that a electron beam flowing into a electrilytic cell does not produce any electrolysis....
You can perform the experiment easily ...
 

Offline Bored chemist

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Re: do radioactive sources produce electricity?
« Reply #13 on: 05/11/2013 20:56:15 »
Nobody could do the experiment easily if they wanted to get the right answer for reasons I have explained an you have ignored.
Also not many people have access to high power radioactive sources.
 

Offline alancalverd

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Re: do radioactive sources produce electricity?
« Reply #14 on: 06/11/2013 23:55:01 »
I've worked on gamma radiolysis with TBq Co-60 sources, neutralisation of static charges with alpha sources, and generation of static charges with beta sources. No indication yet of any gaps in the laws of physics, but I've only been at it every working day for 50 years. Today's exercise involved a few GBq of I-131. Boring stuff behaved just as last time.

An invitation to SC's laboratory would be very welcome. Most of my hair has already fallen out! 
 

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Re: do radioactive sources produce electricity?
« Reply #14 on: 06/11/2013 23:55:01 »

 

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