The dosimetry badge, or TLD badge , used at TRIUMF is
shown in Fig. 6.13 
.
It should be worn at the front of the torso at or above waist level when in
use. The badge consists of a plastic holder with a removable metal insert on
which are mounted two square TLD elements.
The material used for the TLDs is lithium fluoride
(LiF). One of the elements has a very thin aluminized mylar covering to allow
the penetration of beta radiation . This element is
used to measure the shallow equivalent dose
. The other element is behind a filter
which simulates the thickness of
of tissue and measures the deep equivalent
dose 
.
