HV modules for cosmic ray detector(s)

Conundrum, Fri Apr 14 2017, 08:07AM

Hi all.

Does anyone have some of those "block" type 3 wire HV modules originally used on GM counters, etc?
I think they got used in a lot of insulation testers as well as they are very reliable if not ever overloaded.

The ones I have are about 4-800V out at 0.1mA (100uA) it seems, good enough for most purposes
as long as a 10M resistor is added in series.
The ones with 3 pins on a black insulated block are also suitable.

Need 12 total, have 6 maybe 7 if the damaged one (bad insulation) can be patched up somehow.
A few spares would be useful in case one or two go bad.

My alternate option is to make some, they are not that hard as HV853's are good for +130/-90V and
can be obtained for very little $ then driven in antiphase to get the 270V needed for at least an APD.
Some GM tubes will work somewhat on a voltage this low and in fact the "tiny" ones only ever needed 330V to
begin with.
Adding a GM counter to my laptop(s) and phones is on my projects list.

thanks, -Andre
Re: HV modules for cosmic ray detector(s)
Proud Mary, Fri Apr 14 2017, 03:08PM

I use a miniature PCB-type mains isolating transformer - 230:230 - followed by a voltage doubler using small AC rated mains filter capacitors. This will motor along 24/7 delivering around 600V at up to a hundred microamps or so without ever getting warm. Clearly, if I tried to get more current out of it the volts would sag badly because of the low capacitances (100nF) but the power disspitation of GM tubes is very low even at high counting rates.

You could make one using slightly larger capacitors and power all your GM tubes from one HT source. Why make work for yourself?

And no forgetting to put a fuse in the mains input line! wink

Re: HV modules for cosmic ray detector(s)
Conundrum, Thu Apr 20 2017, 11:16AM

Looking into this now, thanks.
BTW my uRADmonitor showed up!
Re: HV modules for cosmic ray detector(s)
Proud Mary, Fri Apr 21 2017, 06:53PM

My home in 146 miles from the centre of Gurnsey. The bearing is approximately North East. This course goes just north of Cherbourg Peninsula, so all but the very beginning and the very end of the journey is made over the sea.
Re: HV modules for cosmic ray detector(s)
Conundrum, Thu Jul 13 2017, 05:52AM

Link2 showing a very strange rise in Sheffield. Faulty sensor maybe?
Re: HV modules for cosmic ray detector(s)
hen918, Thu Jul 13 2017, 10:57AM

Conundrum wrote ...

Link2 showing a very strange rise in Sheffield. Faulty sensor maybe?

I hope it is. I live 20 km from Worksop! It definitely isn't 37 degrees C either.