Volume 2, Number 2 April 2003
TNT Inbox:
Q: The density of film processed through our auto processor is changing slowly and I'm not sure why. The processor seems to be working properly.
A: Check the replenishment rate. If the change in density has been gradual, you may be over or under replenishing. Some common causes could be a detector switch malfunction or adjustment; pump setting, malfunction or accuracy. Filters or lines could be clogged.Q: My company is discussing changing to thermoluminescent dosimeters. What are these and how do they work?
A: Thermoluminescence is the emission of light from an irradiated material after gentle heating. After heating, the amount of light emitted is correlated to the amount of ionizing radiation that was absorbed in the material. Lithium fluoride is the most common material used in gamma and neutron personnel dosimeters. Advantages of thermoluminescent dosimeters (TLDs) include linear dose response, reusability, stability, short readout time and near tissue-equivalence. Disadvantages include loss of information after readout and lack of information about incident radiation that film badges can provide.
E-mail, fax or phone questions for the TNT Inbox to:
Editor, hhumphries@asnt.org
(614) 274-6899 fax
(800) 222-2768 X206
[ The NDT Technician ]
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