From: Paul Doherty (pauld@exploratorium.edu)
Date: Wed Mar 30 2005 - 19:15:28 PST
Message-Id: <21E78FEA-A193-11D9-8828-000A95B38012@exploratorium.edu> From: Paul Doherty <pauld@exploratorium.edu> Subject: Re: pinhole electron accelerator example Date: Wed, 30 Mar 2005 19:15:28 -0800
Geoff is right. A cathode ray tube in a color TV accelerates electrons
to about a third the speed of light.
The Geiger counter is probably detecting x-rays, betas will be easily
stopped by the glass of the tube.
Paul D
On Mar 30, 2005, at 5:45 PM, Geoff Ruth wrote:
> Hi Algis,
>
> It seems to me like what you're describing is a cathode ray tube?
>
> I remember reading once about someone who put up a Geiger counter up
> next to an old classroom cathode ray tube, like the kind you see in
> chem/physics textbooks. The radiation reading was WAY high on the
> Geiger counter. I'm not sure how you'd do this experiment in a way
> that students could both see and be shielded from fast e- (which I
> think is the same as beta radiation).
>
> - Geoff
>
>
>
> Hi pinholers.
>
> I'm always a bit frustrated that most AP physics textbooks spend a
> lot of time developing the concept of charges accelerated in electric
> fields (in a vacuum) which can be very abstract for a student.
>
> When I was reading over a Project Physics textbook from 1970, it
> refers to an experiment that students did: "you can make such an
> electron gun yourself in the laboratory experiment Electron Beam
> Tube." Has anyone done this from years past? Are there any simple
> ways to do this?
>
> I figure one needs a high voltage power supply which I have. I'm
> really looking more for an example than an experiment for students to
> do themselves.
>
> Thanks,
>
> Algis Sodonis
> The Urban School of SF
>
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