380V boost circuit

[weird_dave]

I've been looking at generating 380V for a geiger tube but I've not see one of the transformer based circuits I actually understand
Plus I'd like to make it variable
So I'm thinking of a 555 driving a simple boost circuit (FET, cap, inductor), feeding back to pin 4 of the 555 to turn off the boost at 380V (using a divider and a comparator, with a pot on the other input for variable o/p).
As the voltage drops, the boost is obviously enabled again.
(I suspect I'll need some hysteresis too)

Does this sound reasonable?

 

[davenn]

hi there

I got a geiger counter kit from this company years ago it still works well

Dunno what country you are in, but if not australia they may ship overseas
it would at least take care of your HV problem

Dave

 

[weird_dave]

I'm in the UK.
I don't want to get something off the shelf, especially considering how cheap this should be to build.

My simulation isn't showing great efficiency at the moment