Photomultiplier HV power supply schematic

Hi all!

I googled a lot, but it seems there is no photomultiplier high voltage power supply schematic out there.
Does anyone have such a schematic ?
Preferably, but not necessarily without a transformer. I suppose a simple cascade will do too, since it 'only' requires about 1kV (?)
Those photomultiplier packages with a required power supply of 5VDC or 12VDC don't have any transformer aswell, do they ?

Thank you very much in advance!

All the best,
Hannes.

For the photomuliplier need 80...150V potential-difference between the dinodes. So the (negative) high voltage depend from number of dinodes, and must be stabilised. Because the last two dinodes suck more current, better using two supplies: one for last dinodes with higher current (about 2mA, HI) and another high voltage supply with resistor-divider (about 1500...1800V 1mA)