High Altitude Radiation?

["Tracy N. Tipping" <tipping@phys.ksu.edu>]

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

====================================================================
Tracy N. Tipping                                Work: (913) 532-2668
Laboratory Safety Officer                       FAX:  (913) 532-6806
James R. Macdonald Laboratory                   Home: (913) 539-1378
116 Cardwell Hall                               Amateur Radio: N0OEY
Kansas State University                         tipping@phys.ksu.edu
Manhattan, KS 66506-2604            http://www.phys.ksu.edu/~tipping
====================================================================