Re: Dose to fog camera film

["Dale E. Boyce" <dale@radpro.uchicago.edu>]

I have some info on fogging film.  We used to use 3200 ASA Polaroid
film for locating particle beams at Fermilab.  As I remember 10^7 to 10^8
particles through a square centimeter or so pretty well completely
exposed the film.  This corresponds to between 320 mrad and 3.2 rad.
Supporting this, I have a watch that has a beta dose of about 20 mrad/hr
at contact.  An overnight exposure clearly exposedthe film, although
not completely.  Even allowing for slower film an exposur in the
rad range should clearly fog ordinary film.

Dale Boyce
dale@radpro.uchicago.edu