Re: Radiation Units

["Frohne, Vickie" <VFrohne@BEN.EDU>]

Oops.  You are correct that the 2 R/yr is high. I apologize for not being
more clear...I meant to say that the estimate was fine as rough estimates
go, meaning that this figure is approximately at the correct order of
magnitude. The actual dose for airline personnel is lower than 2 R/yr but I
don't have the number at hand. Commercial planes generally fly at 30,000 to
35,000 feet, so the 96 mR at 9000 ft. from the mentioned chart will indeed
be an underestimate for commercial pilots.

Vickie

-----Original Message-----
From: Ludwik Kowalski [mailto:kowalskiL@MAIL.MONTCLAIR.EDU]
Sent: Friday, September 06, 2002 12:50 PM
To: PHYS-L@lists.nau.edu
Subject: Re: Radiation Units


"Frohne, Vickie" wrote:

> 2 R per year is of the same order of magnitude as the 5 R/yr
> limit for radiation workers and, from what I recall, is
> approximately correct for airline personnel. ...

I still think that the airline personnel gets much less than
2 R/yr. The chart which Vickie found:

http://www.ans.org/pi/raddosechart/

shows that the cosmic rays contribution, at the elevations
8000 to 9000 feet is 96 mR (versus 26 mR at the ground
level). This factor of four should be corrected by the
reduction of the dose from the radioactivity of soil etc.
Using the factor of 4, ignoring the reduction, and assuming
somebody is flying for 10% of the total number of hours
in one year (probably an exaggeration ?), my estimate of
the added dose is 200 mR * 4 *0.1= 80 mR. This is 25
times less that 2 R. Where am I wrong in not accepting
that 2 R/yr is "approximately correct for airline personnel?"
Ludwik Kowalski
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