ABSTRACT
Data from a tissue equivalent proportional counter that was flown at altitudes ranging from 60,000 feet to 70,000 feet were used to estimate radiation quality factors at different latitudes. For high LET radiation, Q values of 11 to 14 were calculated for latitude 18 degrees north to 59 degrees north. Dose equivalent rates ranging from 5.2 microSv hr(-1) to 27 microSv hr(-1) were measured. These dose equivalent rates are about twice that computed using a computer code called CARI-4Q. The dose equivalent received during a flight from Los Angeles to Tokyo was computed using CARI-4Q and the result doubled, based on the TEPC to CARI-4Q ratio. Members of the general public, including frequent flyers, would not exceed dose limits recommended by the ICRP. Air crew would not exceed the limits for occupationally exposed persons. However, pregnant air crew, based on a 2 mSv limit to concepti, would exceed the limit after 150 hours flying time.
