I'd like to switch a 3kV supply and generate a square pulse with a rise time as fast as reasonably achievable.
Please give this a bit of peer review - is this realistically achievable? What passive component values should be used?
A Behlke HTS61-02 module is used, and a few components will be added around it - SHV connectors for the HV signals, connectors for the low-voltage signals, couple of resistors and capacitors.
They quote 5nS rise time, but if I can get even 10-12 nS I'd be happy.
The turn-off time constant is not critical, and the overall duty cycle is like 1%.
A 10uF decoupling capacitor is installed at the +5V supply to the module.
50

RG58 cables are used throughout the system.
The pulse generator's output impedance is unknown.
(I would have suspected 50

, but installing a 50

resistor destroys the signal so apparently it isn't.)
The output level is ~5V. I've connected it to the Behlke module via RG58, and left a placeholder for a possible terminator resistor at the trigger input of the module - not populated yet.
A GP02-40 idiot-proofing diode is put at the SHV connector that brings in the +3kV line, because these supplies can be switched to negative.
A 10nF HV capacitor provides decoupling at the +HV side of the module.
Short ground connections are used for everything - direct connections from the Behlke ground terminals to the metal chassis, with the SHVs directly chassis mounted close to the module.
The load is an electrode in vacuum for an ion-physics application - essentially a DC open circuit, with a small stray capacitance.
A simple 10M:100k voltage divider provides a 100x tap for measurement connected to a 'scope via RG58 cable - I know this is a bit quick and dirty and does not provide frequency compensation.
(Note: 10M resistors on diagram are actually 2M, total resistance of the 5x string is 10M.)
I'm not sure if the R5 / C3 snubber across the switch is needed. Place left for it but not installed at the moment.
Same for the output resistor R4, and the "discharge" resistor R3.
A small DC bias (say +100V) is applied to the output when the switch is off - a series resistor and HV diode are used to protect this power supply.