Hello,

Could you please supply a part number for the "protective gas-gap tube" you used in this build?

Also, while it may not be suited to your needs (only rated up to 2kV), the 1GΩ resistor I've been using to adjust my G–M HV supply cost only $2.64 (US) from Mouser.

Thank you for your time.

P.S. Love your radiation detection projects! Keep up the good work.

I realize this is a very old thread, but I was wondering which model pancake tube you are using?

is it a SI8B?

I ask because, I've never been able to get useful calibration info on it.

Looks like you found some data.

Thanks

Lukw,

Thanks mate.

I got the GM tubes from the eBay seller SOVCOM.

You might find nuclear stuff has gone insane on eBay at the moment thanks to the Fukushima incident. It will likely settle down in time, but at present I see truly insane prices for crappy old civil defense ion chambers - so insensitive they should be calibrated in hours to corpse rather than R/hr.

Regards,

Alan

Hi Alan, love your site content.

I would like to get more information on where to track down these relatively cheap GM tubes. Could you provide an eBay seller's name or a link or any other more specific information?

Simon,

The supply circuit comes from Charles Wenzel's site. It is basically the first 500 volt one, except the zeners setting the output voltage are replaced with the coms-line protection tube.

Charles has a number of ideas for the read-out circuit too. Mine is just an emitter follower coupled to the pulses seen across the tube with a HV capacitor.

Regards,

Alan

Dear Alan,

Great site - how do you find time to fit it all in? Can you point me to a circuit diagram of the power supply used with the Pancake Geiger Muller Tube project as I see that the tubes (or similar) are still available on e-bay and I fancy having a go at building a device.

best wishes

Simon

Quiet. Beginning to wonder if you blew yourself up or had a meltdown or similar...

Happy holidays.

Hello Alan,

Great site!

73

Herb

Alan,

Yeah I've been quiet of late.

Got quite a lot to write about, enough to actually put me off starting. :)

I might even catch up on my email at some point.

Regards,

Alan

Hey Alan! Any new updates! Your site has become dormant.

:)

-A.

Arv,

Thanks for that, ummm, poem. Very creative - really!

The tales of my acute radiation poisoning have been greatly exaggerated. Just been busy with things other than updating the website. I have much to write up, and the tasking gets more and more daunting with each new thing I add to the queue.

Hey that thumb-wheel PTO is a rather good idea, especially for its mechanical stability and relative ease of construction.

Regards,

Alan