If you need assistance, please send an email to forum at 4hv dot org. To ensure your email is not marked as spam, please include the phrase "4hv help" in the subject line. You can also find assistance via IRC, at irc.shadowworld.net, room #hvcomm.
Support 4hv.org!
Donate:
4hv.org is hosted on a dedicated server. Unfortunately, this server costs and we rely on the help of site members to keep 4hv.org running. Please consider donating. We will place your name on the thanks list and you'll be helping to keep 4hv.org alive and free for everyone. Members whose names appear in red bold have donated recently. Green bold denotes those who have recently donated to keep the server carbon neutral.
Special Thanks To:
Aaron Holmes
Aaron Wheeler
Adam Horden
Alan Scrimgeour
Andre
Andrew Haynes
Anonymous000
asabase
Austin Weil
barney
Barry
Bert Hickman
Bill Kukowski
Blitzorn
Brandon Paradelas
Bruce Bowling
BubeeMike
Byong Park
Cesiumsponge
Chris F.
Chris Hooper
Corey Worthington
Derek Woodroffe
Dalus
Dan Strother
Daniel Davis
Daniel Uhrenholt
datasheetarchive
Dave Billington
Dave Marshall
David F.
Dennis Rogers
drelectrix
Dr. John Gudenas
Dr. Spark
E.TexasTesla
eastvoltresearch
Eirik Taylor
Erik Dyakov
Erlend^SE
Finn Hammer
Firebug24k
GalliumMan
Gary Peterson
George Slade
GhostNull
Gordon Mcknight
Graham Armitage
Grant
GreySoul
Henry H
IamSmooth
In memory of Leo Powning
Jacob Cash
James Howells
James Pawson
Jeff Greenfield
Jeff Thomas
Jesse Frost
Jim Mitchell
jlr134
Joe Mastroianni
John Forcina
John Oberg
John Willcutt
Jon Newcomb
klugesmith
Leslie Wright
Lutz Hoffman
Mads Barnkob
Martin King
Mats Karlsson
Matt Gibson
Matthew Guidry
mbd
Michael D'Angelo
Mikkel
mileswaldron
mister_rf
Neil Foster
Nick de Smith
Nick Soroka
nicklenorp
Nik
Norman Stanley
Patrick Coleman
Paul Brodie
Paul Jordan
Paul Montgomery
Ped
Peter Krogen
Peter Terren
PhilGood
Richard Feldman
Robert Bush
Royce Bailey
Scott Fusare
Scott Newman
smiffy
Stella
Steven Busic
Steve Conner
Steve Jones
Steve Ward
Sulaiman
Thomas Coyle
Thomas A. Wallace
Thomas W
Timo
Torch
Ulf Jonsson
vasil
Vaxian
vladi mazzilli
wastehl
Weston
William Kim
William N.
William Stehl
Wesley Venis
The aforementioned have contributed financially to the continuing triumph of 4hv.org. They are deserving of my most heartfelt thanks.
Registered Member #1025
Joined: Sun Sept 23 2007, 07:53PM
Location: Czech Rep.
Posts: 566
So finally my mission in Denmark is over and I’m back in my sweet home Czech Republic. This means I can finally start the Accelerator Project.
Introduction: As most of you already know I’m molecular biologist doing research on DNA damage. What would be very useful for testing some of my ideas is a particle accelerator giving energies around 5MeV. Commercially available devices are incredibly expensive so I’m playing already for some time with idea to build one. I successfully tested some important parts of such device. I mean the HV voltage power supply and voltage divider. Now, the accelerator tube is something which needs to be made and tested and I found somebody who will help with this part of the project. My old friend leading the division of electronics of the Experimental Physics department of our University became a big fan of the accelerator idea. So he is on board - big luck for me!
Project: The project is divided into three separate parts and I’ll try to share all the progress and make detailed upgrades.
Part1: The HV power supply This part of the project is strictly on my shoulders. The idea is to build 2KW 500KV CW multiplier which can stand continuous operation for 30minutes at least. Smaller prototype of such CW I have already tested some time ago and its bigger brother with some modification I will start building now:
As a HF HV transformer supplying the CW stack will be a set of ignition coils. I successfully tested single coil at 1,5KW at 3KHz running continuously for 10 minutes. I’m pumping 300V into the iggy primary and the output is over 50KV. Three coils should make the job (I hope there will be easy way of paralleling them)
The HV diodes for the stack will be based on my published protocol here , no big changes are planned since the diodes are practically immortal. I plan 100pc in each string.
My caps based on transparencies will be modified. I plan to make them oil immersed because I will have access to a vacuum pump of the Experimental physics department. This is not so much to increase the longevity of the caps but rather an elimination of the corona losses. Each cap hidden in PVC water pipe will be 9nF 28KV rated and the CW stack will be based on series of 5 of these caps (means 1.8nf 140 KV DC each cap in the CW stack).
The supporting construction of the CW will be made of PVC water tubes. I have also a small collection of top load balls
Part 2: The voltage divider Basically oil immersed stack of 2W 100K resistors which I tested in my 300KV Marx generator project. Each resistor can easily survive 15KV (despite the original rating is for 2KV!).
Part 3: The accelerator tube We have not decided whether to make it vacuum sealed glass tube or use a tube with a valve and vacuum pump. I have a complete functional old electron microscope with vacuum pump which I rescued to be thrown on the dump. The pump could be used for this purpose but it means additional space and technical demands. However the tube design will be discussed later.
ANY COMMENTS, IDEAS, HINTS, WARNINGS OR RELATED PROTOCOLS WILL BE VERY APPRICIATED.
Registered Member #152
Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384
Yes, some comments :)
Mates wrote ...
Part1: The HV power supply This part of the project is strictly on my shoulders. The idea is to build 2KW 500KV CW multiplier which can stand continuous operation for 30minutes at least.
I think (but I may not be right) that CW multipliers need a lot of reactive power, which increases quickly with more stages. I would not be surprised if the needed kVA input was many times your kW output.
Mates wrote ...
As a HF HV transformer supplying the CW stack will be a set of ignition coils. I successfully tested single coil at 1,5KW at 3KHz running continuously for 10 minutes. I’m pumping 300V into the iggy primary and the output is over 50KV. Three coils should make the job (I hope there will be easy way of paralleling them)
This does not sound right, how did you measure the power? If it was digital multimeter, it was probably wrong. And if you don't have any filter capacitors (which I think you don't from your schematics), you may have actually measured VA not W. 1500VA with shorted output means around 400W maximum real power output.
Edit: I just remembered you use strange schematics with capacitors in line with the mains input. If this was the case, you may have measured a lot of VA through your capacitor.
Registered Member #56
Joined: Thu Feb 09 2006, 05:02AM
Location: Southern Califorina, USA
Posts: 2445
yeah, I doubt you were getting 1.5KW out of an iggy coil, at 50kv or not. Also, 3KHz is a little low for the type of multiplier you are looking for, I would really recommend switching over to a much higher frequiency flyback transformer or the like. Although I guess if your capacitors are free there isn't any harm in using a lot of them...
Registered Member #95
Joined: Thu Feb 09 2006, 04:57PM
Location: Norway
Posts: 1308
Sounds like an awesome project, I can't wait to see how it goes.
For the power supply a large ferrite transformer like the ones used in CCPS / SLR projects would be ideal. Lot's of winding space and you can use a much higher frequency reducing the required size of the capacitors. One big core can easily handle all of the power you need too.
Registered Member #1025
Joined: Sun Sept 23 2007, 07:53PM
Location: Czech Rep.
Posts: 566
Thanks for comments – all are very good points…
Dr. Meh wrote ...
You could probably get some inspiration from Fred Niell's science fair project
Yes, I know this page… Despite my device should be a different scale it is inspiration. At least I know that I’m not completely crazy ;)
aonomus wrote ...
Well the only other thought I had was that you could use the accelerator to make Lichtenberg (sp?) figures.
Yes Lichtenberg figures are planned side product of the project…
Dr. Kilovolt wrote ...
Yes, some comments :) This does not sound right, how did you measure the power? If it was digital multimeter, it was probably wrong. And if you don't have any filter capacitors (which I think you don't from your schematics), you may have actually measured VA not W. 1500VA with shorted output means around 400W maximum real power output.
According to the iggy power – probably you are right and it was much less then 1,5KW. I’m always checking the power meter to get the idea about real power consumption. The rotation speed was approx. half of my electric tea pot which is 2,5KW but that was just a quick look. I will measure it more properly and make this thing more clear ASAP.
Dr. Kilovolt wrote ...
just a question, what do you need such power for?
Why I need so much power? Good question – Maybe 2KW is a total overkill – I have no idea how much power I really need for acceleration of the electrons – these kind of calculations are far from my poor mathematical abilities ;) so I want to be on the save side…I can always decrease the power if I need. The only approximation I have is when I’m using my X-ray for irradiation of cells. I’m using 150KV at 15mA and measurable DNA damage response needs at least 3-8 minutes of irradiation 30cm far from the collimator (means 2-10Gy). I know that X-ray tube is a bit different than accelerator tube but anyway - it is a lot of power.
... wrote ...
yeah, I doubt you were getting 1.5KW out of an iggy coil, at 50kv or not. Also, 3KHz is a little low for the type of multiplier you are looking for, I would really recommend switching over to a much higher frequiency flyback transformer or the like. Although I guess if your capacitors are free there isn't any harm in using a lot of them...
According to the frequency: I successfully run the iggy till 10 KHz but the efficiency peak was around 3,5KHz. Of course the freq can be easily shifted up in case of poor performance of the CW. However I do not plan to go over 6KHz because of the diodes (1N4007 are relatively slow…) Also my caps are relatively big (1,2nF) which should be pretty enough for 3-6K Hz.
Uzzors wrote ...
Sounds like an awesome project, I can't wait to see how it goes.
For the power supply a large ferrite transformer like the ones used in CCPS / SLR projects would be ideal. Lot's of winding space and you can use a much higher frequency reducing the required size of the capacitors. One big core can easily handle all of the power you need too.
I will stick to the iggy coils. I do not have such core and the fast diodes problem persists. I tested the iggy concept already and I know it works…But once I run into a big ferrite core I know what to do with it ;)
Registered Member #1589
Joined: Sun Jul 13 2008, 06:40PM
Location:
Posts: 70
Interesting, I have been pondering upon making such an accelerator, but in a different format.
Since I know that an alternating electromagnetic field can contain electrons, I was thinking about winding the accelerator tube in a style similar to a secondary on a transformer. ie Glass coated in copper, and pumping the tube down. I lacked in the frequency calculation for the type of particle to accelerate though, so I do not know what type of power supply to use. I was thinking around 50kHz would do. At first I was thinking about using my large SGTC (4kW, 89.3kHz) that estimated 400kV or so, but the frequency was not really too stable, since it is a SGTC and all. ((Possibility of a DRSSTC in this condition etc?))
I would not recommend using a Iggie coil for a CW PSU, they're unstable (worse than MOTs in my opinion) and just don't put out that much. I would recommend something like a flyback, or possibly attempt to do a resonant flyback driver, just be sure to make sure it's well insulated. :P If not, wind your own, etc, to make sure it'd well insulated.
To put my opinion out there is: Figure out what you want to accelerate and design it from there, first being tube, power supply designed on decided frequency based on type of particle etc, and then the voltage divider, since the divider is simple and just requires math.
This site is powered by e107, which is released under the GNU GPL License. All work on this site, except where otherwise noted, is licensed under a Creative Commons Attribution-ShareAlike 2.5 License. By submitting any information to this site, you agree that anything submitted will be so licensed. Please read our Disclaimer and Policies page for information on your rights and responsibilities regarding this site.
5MeV Accelerator
