3-5kV HVPS with cascade doubler to 80kV (fwd)

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Chip

---------- Forwarded message ----------
Date: Fri, 05 Oct 2007 12:33:48 -0800
From: Grant Stockly <grant@xxxxxxxxxxx>
To: tesla@xxxxxxxxxx
Subject: 3-5kV HVPS with cascade doubler to 80kV

I am interested in constructing a SMPS suitable for connecting to a 
cascade diode multiplier to get around 80,000V@600uA.  I am trying to 
build a miniature version of large commercial x-ray generators.  I 
have the appropriate safety equipment and experience to be safe with 
x-rays.  : )

This subject probably isn't too on topic here, but this is one of the 
only place where I thought I could get the right people with the best 
answers.  : )

The first step is to choose the transformer configuration.  I've 
thought of using either 3kV or 5kV as the secondary voltage.  3kV 
would allow for less expensive capacitors, but would require more 
doubler stages.  5kV would reduce the number of doubler stages, but 
possibly be harder to design a transformer for.

The primary winding will be driven off of either 24v or 12v, most likely 24v.

The plan I have so far is:
-Flyback Converter
-ETD34 core
-24kHz

-12v primary (10-15), 11 turns of 16ga - 3kV Secondary @ 16.66mA, 
2641 turns of 30ga
or
-24v primary (20-30), 21 turns of 18ga - 3kV Secondary @ 16.66mA, 
2521 turns of 30ga

-Cockcroft Walton Voltage cascade multipliers
-Half Wave - 20 stages, 3.457nF capacitors
-Full Wave - 15 stages, 1.892nF capacitors

I like the full wave multiplier because of the output ripple (~100v), 
of course the capacitors on the full wave could be chosen for the 
lower stages to reduce ripple.

Any tips or hints?  Any reference designs that may help me?

I will probably have to use silicon insulated wire with the 
appropriate dielectric strength for the secondary, right?

Thanks,
Grant