Re: ?Wearing Neutron TLD under ice-vest

[BFLOOD@SLAC.Stanford.EDU (Bob Flood)]

>     A question has been raised regarding the wearing of a Panasonic UD802 
>     neutron TLD under an ice-vest when making power entries. My opinion is 
>     that the neutron TLD should be worn on the outside of the vest, as is 
>     the case with all other activities, including power entries where an 
>     ice vest is not worn. I also believe that there would be some 
>     under-response for both the gamma and neutron components, the degree 
>     being unknown.

The purpose is to determine the dose to the wearer of the vest, not to the
vest. Therefore, placement under the vest provides a measurement applicable
to that part of the body (most of the torso) inside the vest. This
measurement should be acceptably accurate for both gamma and neutron
radiations. The confounding factor is the dose to components of the whole
body not shielded by the vest and to the lens of the eye. A single TLD
outside the vest may overestimate the gamma dose to the shielded torso and
underestimate the neutron dose (possibly severely) due to interference with
the albedo measurement geometry. I suggest using at least 2 dosimeters, one
under the vest and the other outside at a convenient spot near the collar
area (to estimate eye dose). More may be necessary if there is a measurable
nonuniformity to the radiation fields.
Bob Flood
Unless otherwise noted, all opinions are mine alone.
(415) 926-3793
bflood@slac.stanford.edu