Compact subnanosecond high voltage pulse generation system for cell electro-manipulation

A solid-state sub-nanosecond rise time pulse generator for driving variable impedance biological loads, the pulse generator comprising:

• a) a transmission line comprising a series chain of N (N is integer number >=2) avalanche transistors configured to switch a high voltage DC supply to substantially ground within hundreds of picoseconds and to generate high voltage electric pulses having a sub-nanosecond (<1 ns) rise time;
• b) a trigger circuit to initiate the switching via an avalanche breakdown mechanism in the transistors of the transmission line from a lower end voltage side to a higher end voltage side;
• c) N capacitors electrically connected to collectors of each avalanche transistor, configured so that the capacitor's impedance decreases from the lower end voltage side to the higher end voltage side;
• d) a chain of N zener diodes, each placed across a corresponding avalanche transistor, the chain configured to divide a high voltage DC supply across the transistors, wherein the diodes are so configured as to enable a non-destructive avalanche breakdown of the transistor or transistors of the higher end voltage side upon triggering from the transistor or transistors of the lower end voltage side, wherein the zener diode or zener diodes at the higher end voltage side are configured to have a lower nominal voltage rating than the zener diode or zener diodes at the lower end voltage side.