DU dose on contact, film

["Robert Gunter" <rjgunter@icnpharm.com>]

Dose on contact is about 233 mr/hr according to the 1970 RHH.  In my
experience the number varies according to who you talk to.  I have seen
dose rates quoted from 205 mr/hr up to the 233.  The interesting part is
when a dosimeter is placed on contact, the dose rates all appear to be the
same irregardless of what the irradiation facility says.  I guess it
depends on how good someone is with an extrapolation chamber.  People talk
about coatings on the slabs which will affect the Beta dose rate.

Regarding film exposure, you have the Betas, but also some gammas.  The
dose registered at 1000 mg/cm^2 is about 5% of the shallow dose on contact
using TLD.  You can stretch that out to 10 cm to see what you will get.
The other thing to consider is the speed of the film and therefor it's
relative sensitivity to radiation.  Higher speed = more sensitive.
Personal monitoring film is essentially B&W.  I don't have a number on the
ASA rating.  It is sensitive to light, but not designed to register light
in the same way as photographic film.


Rob

---------------------------------------------------------------------------
        -------------------------------

Robert J. Gunter         Tel: (714) 545-0100

Sr. Technical Specialist      Tel: (800) 548-5100 Ext. 2414

ICN Biomedicals, Inc.         Fax: (714) 668-3149

Dosimetry Division       Email: rjgunter@icnpharm.com

3300 Hyland Avenue

Costa Mesa, CA  92626










************************************************************************
The RADSAFE Frequently Asked Questions list, archives and subscription
information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html