October 17, 1951

A. The routine personnel monitoring at BNL makes use of film badges and
pocket chambers. The film recommended is Dupont 508 Adlux. This film pack has
a range of 10 mr to 1000 r. Dupont 552 having a range of 50 mr to 40 r has been
used in the past. Each of the film badges contains two photographic films, one
being much more sensitive then the other.

The pocket chambers used include those manufactured by Victoreen, Keleket,
and Cambridge. Most of the chambers are made by Victoreen.

Film badges containing Kodak NTA nuclear emulsion on an acetate base are
used in neutron monitoring. Neutrons are detected by the proton recoil method.
A weekly fast neutron tolerance dose results in eight proton recoils per
twenty-four fields of view with a field diameter of 150 microns.

B. All photographic work is carried out in an air conditioned laboratory.
It is recommended that this work be done in a cold region away from the reactor
and hot laboratories.

C. Weston densitometers with a modified expanded low scale are used in
reading film badges. One Photovolt densitometer is also used. It is a more
versatile although a more expensive instrument.

D. It is recommended that the dessicant be removed from the caps of the
Victoreen pocket chambers and the uncapped chambers be stored in a drying cabinet.
Such a cabinet can be built by adding five incandescent lamps to each shelf of a
standard metal storage cabinet. Fifteen watt lamps are burned continuously
resulting in a temperature of approximately 90°F.

L. Faulty pocket chambers can very often be repaired by replacing the central
electrode. Those electrodes are available from the Victoreen Company.