You may be able to find some info in the ALARA notes at the Brookhaven National Lab's ALARA Center: http://www.dne.bnl.gov/alara/brochure.htm Regards, Ben ben.morgan@cplc.com ************************************************************************ The RADSAFE Frequently Asked Questions list, archives and subscription information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html