[ RadSafe ] TLD Sensitivity

[Robert J. Gunter]

Greetings All, especially you TLD folks.  Glad to see you are monitoring the
list!!

As noted by everyone, TLD materials have different sensitivity, and angular
shots can cause other problems.  Remember the TLD's are calibrated in fixed
90 degree geometry so an angular shot will result in a difference in
recorded response.  This is more of a factor for a whole body badge as the
filtration over each element of the badge changes leading to improper
algorithm choices when trying to determine the exposure energy.

That is the biggest difference between whole body badges and extremity.  If
a whole body badge is exposed, (presumably) there are multiple elements
under various filtrations and when read, a dose algorithm identifies the
energy based on the response of all elements and applies a dose factor to
whatever element reading is typically used.

Extremity dosimeters may or may not have more than one element.  If not,
then no algorithm is selected based on response, rather a default is used.
That is the biggest difference.  You might compare raw element response
(correcting for mass differences in the elements) in a similarly filtered
element in the whole body badge to the extremity.  Assuming the materials
are the same, the reading should be comparable, barring geometry differences
(angularity).

Good luck!!

Robert J. Gunter, CHP
CHP Consultants
Oak Ridge, TN
Ph:  (865) 387-0028
Fax: (865) 483-7189
rjgunter at chpconsultants.com
Products and Services at:
www.chpconsultants.com