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Re: Thinking About A Geiger Counter

Original poster: Jim Lux <jimlux@xxxxxxxxxxxxx>

At 08:06 PM 11/3/2005, you wrote: 
Original poster: Skip Malley <skip@xxxxxxxxxxxxxxx>

A Geiger counter measures particles released from Uranium and has ABSOLUTELY NOTHING to do with the relatively low frequency energy of a Tesla coil which is in the frequency range of an AM radio transmitter.

Geiger counters will measure any ionizing radiation of sufficient energy, including X-rays. Cosmic rays don't come from U, and probably constitute about half the background radiation. They're a lot higher energy than most of the particles coming off natural U.

While it's true that the TC itself isn't going to be emitting any ionizing radiation, see below for a discussion of the problems that arise in connection with HV and vacuum together.

It is like using an ultrasonic microphone listening for earthquakes. Tesla coils emit low frequency radio waves, not gamma rays.

Geiger counter measurements are of ABSOLUTELY no value to a coiler, unless you live next to a Uranium mine.

I have to differ here.
Cory said he's working with high voltage and vacuum, which is a recipe for X-rays. This is something that anyone working with HV and vacuum needs to be aware of. Not so many years ago, Xray emission from the HV rectifiers in color TVs was an issue. You may decide that the possible dose is so small it's not worth monitoring. Or, you might decide that you need some monitoring. I suspect the decision might be influenced by your gender and age: Women carry around all their eggs for life, so the possibility radiation induced damage at any point is a problem for the rest of their life. Young people might consider the increased risk of problems from the ionizing radiation more of a problem than someone who's older.

I'd be slightly nervous about operating HV in a vacuum system, unless I was real sure there's no possibility of electron beams, etc., without shielding or with some sort of monitoring, not to mention dosimetry. I'd be a whole lot more nervous about my 9 and 12 year old daughters being in the room. not only are they young and female, they're smaller, so there's less "stuff" between the inner organs and the outside world.

A short duration dose is probably not a big deal, either. A few mA of beam current for a few minutes every month isn't a big deal. Sitting in the same room, hour after hour, with 100s of mA beam current is a different story entirely.

The real question is whether conventionally available geiger counters (which use Geiger Muller tubes as the detector) would be of any value as radiation detectors or dose alarms. My gut feel is that they wouldn't. The inexpensive counters (i.e. the Aware RM-60, which I have) have tubes that are too small and insensitive to be of value for detecting soft xrays.

I'd be more inclined to go the computational route and make sure I had enough shielding and/or distance. Perhaps one might get a dosimeter or borrow a sensitive one.



Skip

At 10:45 AM 11/2/2005, you wrote: 
Original poster: "coryrc" <coryrc@xxxxxxxxx>

With all the high voltage work I do around Vacuums I thought it might be
good to get a gamma scout. (http://www.gammascout.com/geiger-counter.html)
Just in case I am x-raying myself, it would also be nice to know my exposure
through the year. Any thoughts would be great, also wondering if any fellow
coilers had a gamma scout, or have found something better?

Happy Coilin',
Cory Capps