Re: Discrpancies among different dosimeters

["Sandy Perle" <sandyfl@earthlink.net>]

> I assume the metal clip of a TLD holder would have a large effect if it were 
> situated between the x-ray source and the TLD chip.

Mike,

The clip could have an effect. In Myung's post, it is stated that the 
x-ray energy was between 0 - 2.8 MeV, and none < 60 keV. That's 
a pretty broad range. Since the lower range is above 60 keV, I'd 
expect some variation, but not to the extent that the data 
demonstrates. I have evaluated lots of data from TLDs over the past 
25 years, and irradiations through the back do vary, but not 
significantly. Once you get over 200 keV, there is essentially no 
effect, in that the x-ray is more like a high energy photon, and the 
extra thickness of the clip doesn't add much density, therefore, 
only causing a small reduction in response.



Sandy Perle
E-Mail: sandyfl@earthlink.net 
Personal Website: http://www.geocities.com/capecanaveral/1205

"The object of opening the mind, as of opening 
the mouth, is to close it again on something solid"
              - G. K. Chesterton -
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