I've been able to determine all values for all components, And I've been able to generate a wave which meets the specifications
rise time 5ns +- 30%; duration time (to 50%) = 50ns +- 30%; Vpeak = 1000V +- 10%
The problem with this method is that I cannot vary the voltage from 0V to 4kV, as the avalanche circuit only works for a certain voltage range.
As I would like to make the output voltage variable from 0v to 4kV, I am looking for another way to implement the switch. It needs to switch within 5ns.
If anyone has an idea on how to do this, thanks in advance.