Re: High Altitude Radiation?

[rkathren@tricity.wsu.edu (Ron L. Kathren)]

Just returned from being away for a few days and saw your questions re count
rate vs. altitude.  What you saw is exactly what would be expected.  Cosmic
ray intensity (largely scondaries -- ie photons) increases with altitude,
reaches a peak and then drops off.  Also, the efficiency of the detector
differs for different energies, which plays a part in what you saw.  Details
are available in Chapter of "Radioactivity in the Environment", Harwood
Academic Press, 1984.


Ron Kathren>
>Howdy,
>
>Our campus amateur radio club recently launched a balloon with an 
>amateur radio package attached.  In addition to the amateur radio 
>gear, there was a Geiger counter and data acquisition system on board. 
>They looked at the data and then came to me with questions.  They 
>basically were looking at counting rate versus altitude.  The numbers 
>they got are (cpm = counts per minute):
>
>    ground - 16cpm
>    60,000ft - 800cpm
>    90,000ft - 600cpm
>
>According to the manufacturers calibration data, 1cpm = 1 microR/hour.
>
>Their questions are:
>
>1) Why is the counting rate higher at 60,000 than 90,000?
>
>2) What kind of radiations are they seeing (x-rays, mesons)?
>
>Any thoughts?
>
>Thanks,
>
>Tracy
>
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>Tracy N. Tipping                                Work: (913) 532-2668
>Laboratory Safety Officer                       FAX:  (913) 532-6806
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>