Date: Tue, 27 Mar 2012 15:36:49

Author: --- "George

Subject: Re: Cathode Ray Tube demo - Radiation hazard


Just out of curiosity, how did they measure the X-rays? How close was the detector to the tube? Did they measure at the typical distance at which a student would be located away from the tube or right beside the tube? Intensity does decline with distance.
I'm also curious about exposure time before the X-rays are considered dangerous. Thanks for any information. This sort of thing seems to be ignored in regard to these types of apparatus.

George Weremczuk
Department of Physical Sciences
Thompson Rivers University
Box 3010
Kamloops, BC V2C 0C8
Phone (250)828-5448

>>> Richard Flarend 27/03/2012 3:17 pm >>>
Our health and safety people came to do a survey of some radiation labs, and being the stupid person that I am, I asked them to look at our cathode ray tube demo (which I recall a vendor in Portland saying produced x-rays). Wellllll, it did produce x-rays, way over the limit for what is allowed here by whatever law or regulation they say covers this.
Here is the exact apparatus that we use (thanks for the picture Dale), only with a different power supply. Has anyone else measured the x-rays coming from their apparatus? Our health and safety folks are reluctant to allow me to use a lower voltage source because they say it will just produce lower energy x-rays, possibly below the detection limit of their detector. They are suggesting building a shield with leaded plexiglass which would then make it harder to see what is happening (and cost money). That vendor at Portland was promoting a device that I think he said solved this problem...of course one has to wonder how?

Richard F