Building a High Voltage Rectifier with a continuous negative output

Question

^{simulate this circuit – Schematic created using CircuitLab}

In the past, I have worked with high voltage projects, but seldom with HV rectifiers. Thus, I was curious how I could build a rectifier that could take 70 kV AC and 10 mA to put out a continuous, negative DC voltage with minimal ripples. The frequency for the input is 60 Hz and is provided by a X-ray transformer that provides adjustable voltage from 0-70 kV AC.

Note on image below: There was not an option for a variable transformer image, so I used a non-center tapped transformer to depict it.

Answer 1

The frequency for the input is 60 Hz and is provided by a X-ray transformer that provides adjustable voltage from 0-70 kV AC

Some more modern X-ray machines generate a high frequency (10 kHz to 100 kHz) variable AC voltage of several kV magnitude and then use a Cockcroft Walton multiplier like below: -

This both performs AC to DC rectification and, each stage need only be rated for the peak voltage from the AC source hence 10 kV rated diodes and capacitors can be used.

I was curious how I could build a rectifier that could take 70 kV AC and 10 mA to put out a continuous, negative DC voltage with minimal ripples.

If you can't find diodes rated at over 100 kV DC then a good option is to scrap the X-ray transformer method and use the multiplier shown above. Minimal ripple is meaningless but if you are driving a tungsten target X-ray tube then a few volts p-p isn't going to be a problem.