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450KV 225nF marx bank questions

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Ash Small

Thu Mar 07 2013, 03:35PM

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

colin heath wrote ...

Hi Ash, that sounds like a plan. Are you talking particle or metal object accelerator though :)

Protons, mostly.

colin heath

Thu Mar 07 2013, 04:14PM

Registered Member #123 Joined: Fri Feb 10 2006, 12:58PM
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Posts: 162

Ash Small wrote ...

colin heath wrote ...

Hi Ash, that sounds like a plan. Are you talking particle or metal object accelerator though :)

Protons, mostly.

This sounds interesting! So are you thinking marx based design with potential rings tapped off each stage? or something completely different?

Also something with the potential power of this will need burying in a large pit to contain the nasties emitted!

Ignore above my addled brain getting cockcroft walton accelerator mixed up!

Ash Small

Thu Mar 07 2013, 05:21PM

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

Well, so far, I'm just starting winding secondaries for a 50kV, 5kW, ~25kHz transformer, and the idea is to put a CW multiplier 'inside' the vacuum chamber, using capacitor plates (aka vacuum capacitor) and VMI glass diodes, so that outgassing isn't an issue. ~15 stages, after losses, will hopefully be ~650kV. As you're already aware, I have a fair bit of vacuum equipment already.

I've not crunched the numbers for X-ray emission yet, but the idea is to produce Alpha's, which shouldn't require much shielding anyway. Any Neutrons produced by secondary reactions will hopefully not be produced in any great quantity, although the subject of emissions will require further research/number crunching once I have a better idea of whether the various sub-systems are going to work or not (There are some very knowlegable people on this forum who I'm sure will be able to check my sums, etc.).

As long as power is under 1MeV, no licence is required. I've been working on this for a few years already, on and off, since shortly before I bought that first lot of vacuum equipment from you. I've outlined the ion source design over on Cyclotrons.net, and I've recieved a lot of advice regarding the main power supply here on this forum.

I think I've overcome all the obstacles identified since I first outlined the plan over on fusor.net a few years ago, the clever bit is putting the multiplier inside the chamber, so all the 'real' HV (anything over 50kV) is contained inside the chamber. The VMI diodes aren't cheap though, but they are military spec.

mikeselectricstuff

Thu Mar 07 2013, 09:12PM

Registered Member #311 Joined: Sun Mar 12 2006, 08:28PM
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Posts: 253

I make that about 2kJ - that would be one almighty bang - forget EMP, UV, ear and shock-wave protection may be bigger issues!

teravolt

Fri Mar 08 2013, 04:32AM

Registered Member #195 Joined: Fri Feb 17 2006, 08:27PM
Location: Berkeley, ca.
Posts: 1111

hi Colin, those caps are great for teslas too but it would make a awsum marx. you will have to stack them verticaly and make some sort of wood or plastic stand. I used carbon comp. inductors and liquid resistors could also be used. it would be one hell of a crack with a big spark. you may never have the opertunity again you just need to be carefull

vircator

Fri Mar 08 2013, 06:02AM

Registered Member #3217 Joined: Mon Sept 20 2010, 06:14AM
Location: Switzerland
Posts: 15

colin heath wrote ...

Then after firing a few times what do I do with it?

I know what I would do with this wonderful Maxwell caps. Yes, I would build a Marx as well. Demonstrate the vulnerability of our todays society to EMP (in a responsible way of course). Build a Vircator. Build a flash X-ray etc etc...
If you don't have any ideas... I would be happy to take your caps

colin heath

Fri Mar 08 2013, 10:33AM

Registered Member #123 Joined: Fri Feb 10 2006, 12:58PM
Location:
Posts: 162

OK maybe I should build it then just for some fun i can always use the caps for other things later such as UK's biggest tesla coil ;)
The plan was to use inductors as the cost of resistors to handle that power and voltage are crazy.

As mike says it will be around 2kJ so will have to take some precautions around noise and maybe even pressure wave from this.
I think remote trigger from a distance but I think more calculations will be required in theory before firing! I can then put the thing to use on exploding wire, EMP and maybe rent it out for lightning testing of equipment :)

teravolt

Sat Mar 09 2013, 05:39PM

Registered Member #195 Joined: Fri Feb 17 2006, 08:27PM
Location: Berkeley, ca.
Posts: 1111

Hi Colin. I think that liquid resistors are a good choice because they can be be made with tygon tubing and salt water. They are flexible and cost efective

HV Enthusiast

Sat Mar 09 2013, 06:54PM

Registered Member #15 Joined: Thu Feb 02 2006, 01:11PM
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Posts: 3068

Those are some SERIOUS caps.

Okay, i'll have to warn you - you DO NOT want to fire this anywhere near your home or another persons home with that type of energy.

I build several marx generators about 10 years ago and only used something like 3300pF per stage, but it was enough to take out the TV, cablebox, alarm system, and thermostats in my home from a single fire.

These are poor man's EMP generators, and will induce huge voltage spikes on any high impedance wiring you have in your home and blow out lots of electronics.

You can always build it up, and use a generator to power it up and fire it outside in the woods.

Otherwise, you'll need a shielded room to fire it in. Thats why all those HV labs in the universities are built in GIANT shield rooms.

Good luck! Its going to be a MASSIVE output pulse with those caps.

And be safe - the output discharge from that (even just stage discharge) will kill you.

colin heath

Sat Mar 09 2013, 08:40PM

Registered Member #123 Joined: Fri Feb 10 2006, 12:58PM
Location:
Posts: 162

I am still unsure if the build time will warrant the use. I will have to transport this thing else where just to use it!
Maybe need to think of something else to do with the caps??

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