RE: Panasonic UD-716 badge reader

["Lantz, Michael W(Z59078)" <MLANTZ@apsc.com>]

I would agree with the previous responses to you about anomalous TLD 
readings.  Mr. Volschenk noted a number of issues to evaluate.  I 
would add that a microscopic review of the teflon bubble of the TLD 
elements at 30 to 60 power is important.  The LiBO elements are 
especially susceptible to damage from many chemicals, with water or 
sweat being leading candidates.  Check the teflon bubble carefully for 
clouding related to "washed" phosphor.  Occasionally, we find red and 
blue threads on the anomalous elements and these can provide TL.

As Mr. Volschenk alluded to, check the post anneal value against the 
main peak in the glow curve.  The ratio is often very different than 
radiation-induced TL ratios.


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From: 	David Arnold[SMTP:cotteril@sghms.ac.uk]
Sent: 	Friday, May 09, 1997 1:30 AM
To: 	Multiple recipients of list
Subject: 	Panasonic UD-716 badge reader

Recently we have had a couple of false high dose readings. Readout of 
the backup elements fails to confirm the doses and the wearers'
of the badges confirm that they have done nothing out of the ordinary, 
work wise.

Has anyone out there had similar experiences of spurious dose
readings?  Any comments/explanations welcome.

Regards,

Dave Arnold
The Radiological Protection Centre
St. George's Hospital
London