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AW: AW: Denver, BEWARE!
Franz Schoenhofer
PhD, MR iR
Habicherg. 31/7
A-1160 Vienna
AUSTRIA
phone -43-0699-1168-1319
> -----Ursprüngliche Nachricht-----
> Von: owner-radsafe@list.vanderbilt.edu [mailto:owner-
> radsafe@list.vanderbilt.edu] Im Auftrag von J. Marshall Reber
> Gesendet: Montag, 20. Dezember 2004 14:44
> An: Richard L. Hess
> Cc: radsafe@list.vanderbilt.edu
> Betreff: Re: AW: Denver, BEWARE!
>
> > I made on an airplane a few years ago--and at altitude (IIRC about
> > 41,000 feet) we were up at about 250µR per hour (as measured on an
> > Aware RM-70 pancake G-M tube)
>
> Does the RM-70 have a provision to shield out the alphas and betas in
> order to use the gamma sensitivity factor to legitimately convert the
> counts to µR/h?
>
--------------------------------------------------
Alphas are shielded by as little as a paper sheet, betas are probably
shielded by the metal of the plane. The rest is not only gammas, but to
a large and varying extent neutrons, which will not be detected by a
Geiger-Mueller tube. Therefore the real dose is always higher than the
one measured with a simple instrument. Additionally the dose factors for
heavy particles from the cosmic rays are not known very well.
Nevertheless it is a good demonstration that dose-rates increase with
altitude.
Best regards,
Franz
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