Thanks for the reply!
I would like to use this HV at the semiconductor radiation detector and i would like to set the HV between 0 to 1500Volts from the 4,5V. This is the reason of my question. I need to choose the good frequency with associated duty cycle and inductance. I have found the MOSFET transistor. I think after that using voltage multiplier with capacitance and diode. The current of charge is about 100uA.