Diy linear accelerator

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Sarmad suseyn
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Diy linear accelerator

Post by Sarmad suseyn »

Hi guys
Full curfew is killing me. Have nothing to do.
So i decided to do any project . Dont kill me for that🤪.
A very simple linear accelerator just for testing
I used 15kv ac and 750 v dc powers supplies .
The result wat interesting but i need more ac voltage and bigger housing in the future. Got 276 counts = 1.25usv/h
Which is not bad . But it could be better with more voltage and vacuum.
Any ideas to improve?
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Richard Hull
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Re: Diy linear accelerator

Post by Richard Hull »

Cool, simple design. The spacing and length of the drift tubes is a critical function of the frequency if the design is to be successful in the fullest sense of the hoped for result. Otherwise, it is just an x-ray system.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Rich Feldman
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Re: Diy linear accelerator

Post by Rich Feldman »

Very cool looking. Thank you for jumping into fabrication, and photography, and reporting.

Is it ordinary air inside? Partial vacuum? What pressure?

Your description is missing important circuit details, like the external connection between HV AC and the other two power sources.
Schematic diagram is one way to present those connections.

Your measurement, maybe attributed to penetrating radiation, is meaningless without a control reading.
Not by turning off the accelerator tube, but by blocking the purported beam with a piece of lead or something.
So we know what fraction of the 276 CPM are due to HV circuit interfering with the detector operation.

How do the measurements respond to changes in your electric power variables? Or to presence of a strong magnet?
All models are wrong; some models are useful. -- George Box
Sarmad suseyn
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Re: Diy linear accelerator

Post by Sarmad suseyn »

Hi
No the vacuum is there of course. I think its one stage vacuum pump. The vacuum around -30 psi .
Im using 3 power suppliers two connected and one is not, check attached pic.
In the first i thought its electrical interference from the high voltage. This why i checked the tube with Geiger counter before and after putting the electron gun on. So its not electrical interference. Dont forget the outer shell is a thick pvc pipe for high pressure water. About xrays im not sure right now. I just ordered ludlum scaler 2200 with NI probe ( in the way) Then i will check its xray or not.
The drift tubes are different in length its important.
This just an experiment. And my aim is not to speed electrons
But its for bigger atoms like hydrogen or protons.
I want it more bigger and more power
It means more vacuum more voltage bigger drift tubes and more hv frequencies
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IMG-20200525-WA0048.jpg
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Rich Feldman
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Re: Diy linear accelerator

Post by Rich Feldman »

Thank you.

By more vacuum, do you mean stronger than -30 psi?

If the HV AC power supply is not battery powered, it must have more than two terminals.
How are the other terminals (power input and ground?) connected to the inputs or outputs of the other power supplies? It matters!

What is the frequency of HV AC, and how is that related to the length of parts in your tube design?
All models are wrong; some models are useful. -- George Box
Sarmad suseyn
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Re: Diy linear accelerator

Post by Sarmad suseyn »

Hi rich
I feel i need more vacuum power for example 2 stage vacuum 😔
The more bigger the linear the more frequency it requires
Not khz but mhz.
The bower Ac powder supply im using between 21-24 khz
The dc hv Module is from 400v to 1000 v
It's a neon transformer.
It has 2 leads only not 3.
Regarding drift tubes im attaching pdf.
Attachments
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Screenshot_20200527-101628_Samsung Internet.jpg
Proton_3.pdf
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Maciek Szymanski
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Re: Diy linear accelerator

Post by Maciek Szymanski »

Here you are an article about one of the first drift tube liniacs (when they were just couple of laboratory glassware, coper wires and shellac seals) "The production of high speed canal rays without the use of high voltages" by E.O.Lawrence and D.H.Sloan. With this desktop setup they got ion energies in 100keV range:

https://www.dropbox.com/s/f1fq4w0h7v0zb ... s.pdf?dl=0
Last edited by Maciek Szymanski on Wed May 27, 2020 11:36 am, edited 1 time in total.
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Sarmad suseyn
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Re: Diy linear accelerator

Post by Sarmad suseyn »

That was a joke right ? No files......no comment
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Maciek Szymanski
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Re: Diy linear accelerator

Post by Maciek Szymanski »

Sorry, I’ve made a mistake in the link. It should work now.
“Begin at the beginning," the King said, very gravely, "and go on till you come to the end: then stop.” ― Lewis Carroll, Alice in Wonderland
Sarmad suseyn
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Re: Diy linear accelerator

Post by Sarmad suseyn »

Hi
If you noticed but there is hv !!!!
The design similar to what i built.!
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John Futter
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Re: Diy linear accelerator

Post by John Futter »

Sarmad
Thank you for posting the neon transformer specifications

just note that the transformer is 120 watts input so output less because of losses in the circuitry

the output claimed is a little misleading as they are trying to say its 360 watts output

not so ----neons need lots of volts to strike then settle to much lower voltages to run hence the 12kV but the run for a neon tube is 100 - 1000 volts depending on length and diameter

so running 1000 volts @ 30 mA gives 30 watts -- a clue is neon tubes run warm not hot ie a few watts / per foot

be careful that little black box will not last too long at continuous high power output
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Dennis P Brown
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Re: Diy linear accelerator

Post by Dennis P Brown »

The vacuum requirements for a linac (or any drift like linear accelerator) is very high - for a moderate length, 10^-6 torr is mandatory; otherwise, collsions will cause the gas molecules in the tube to scatter/ionize preventing any acceleration of your desired ions. No two stage pump will work alone. You need either a turbo or a diffusion pump (DP) with a trap and approperate gauges. This isn't easy - I built one. The required high vacuum is very difficult to achieve with couplings (been there, done that.) Your -30 inch of Hg indicates you are rather new at vacuum work. Units here are generally torr and negative inches is, to say the least, a rather nonsensical unit if you think about it.
Sarmad suseyn
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Re: Diy linear accelerator

Post by Sarmad suseyn »

Hi dennis
Thanks for the information. I agree with regarding the turbomolecular pump . You said you already did it before. Can you share some information .about the build.
Thanks
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Richard Hull
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Re: Diy linear accelerator

Post by Richard Hull »

Like pretty pictures of a complete system build? Try this obvious FAQ with captions and explanations. This system uses a diff pump, the absolute least expensive secondary pump. READ all the FAQs on all subjects!

viewtopic.php?f=24&t=13055

More pretty pictures of a complete recent build using a turbo pump (spread over 5 pages). A fabulous vacuum system build using a list price $5000 turbo pump and controller. Terrible fusor, however.

viewtopic.php?f=6&t=13176

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Rich Feldman
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Re: Diy linear accelerator

Post by Rich Feldman »

Couple more points.

Sarmad's original statement of vacuum was not -30 inches, it was more than twice as strong: -30 psi.

The neon sign power supply does _not_ have two terminals, There are at least four, if we count AC power input and maybe ground.
Here is why those matter, and schematic is incomplete without them.
It is important to know the electrical connection, outside the drift tube, between DC and AC power supplies.
(As we see in the Lawrence and Sloan figure, which also features thick connection to vacuum pump.)
Otherwise the relative potential is undefined. Actually it would be determined by internal particle currents and external leakage.
All models are wrong; some models are useful. -- George Box
Sarmad suseyn
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Re: Diy linear accelerator

Post by Sarmad suseyn »

Dear rich
The hv ac power supply have the total 5
Input 3 L ,N AND Ground
Output 2
This what i have in it.
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Dennis P Brown
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Re: Diy linear accelerator

Post by Dennis P Brown »

Well, rather than make you search through my far too many posts on the subject (I really bored everyone on that score; sorry) here is a link to pics of the device - it is fairly big and there are a number of pics:
viewtopic.php?f=18&t=9359&p=63240&hilit ... tor#p63240

Again, use either Pa or Torr (preferred here) for vacuum units and never use negative units. That is very sloppy and are not really valid (sorry engineer's but that is just the way it is.)

Negative 30 psi for a vacuum is physically impossible - think about that and why, Rich (unless, maybe, we are talking dark matter? ;) .)

Now there are vacuum gauges that display -30 inches of Hg so that is what I assumed he really meant and just mistyped getting psi.

A small deuterium or other ion gun is a worthy project and if you can get a turbo, well worth the effort; I'd suggest stay away from accelerator level devices [requiring stages (i.e. couplings! The bane of high vacuum!)]. My such device did not turn out well for me - lol. My issue was the accelerating field - not the vacuum (but that took a long time to get right.) I will, time permitting, revisit that old work if I get time once my new facility (i.e. overbuilt out door shed) is contructed.
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