Re: A couple off-the-wall (unrelated) questions

[a.zapantis@qut.edu.au (Alex Zapantis)]

G'day Jim,

>#1.  What recommendations do other research institutions follow for monitoring
>technicians in x-ray diffraction labs. We have a couple units on campus made by
>Scintag (an XDS2000 and a PADII), which are fully enclosed and shielded, so
>that exposures to all users have been less than detectable. In fact, the area
>monitors do not even register any exposures.

Here in Oz we follow the relevant National Health & Medical Research Council
Code of Practice. If you Like I will mail you one. It requires that
operators of enclosed XRD/XRF units wear TLDs or film badges and that
monitoring for leakage with a suitable detector be undertaken quarterly.
Area monitors seem like a bit of overkill. Do you not have any other areas
where they could be more usefull (WE DO!! I could swap you the Code of
Practice for the monitors, any hope??!!)


>#2.  Can pancake geiger detectors be set off by high electromagnetic fields?
>Yesterday one of our techs was out surveying a lab and thought he had a short
>in his cable because the meter pegged as soon as it was turned on. He went back
>to get another geiger counter and the same thing happened in the same lab, but
>only near a bench with a number of lab instruments running on it. There was no 
>radioactive contamination, it seemed to just be from the instruments themselves
>(a compressor, water bath and speed-vac). Excuse my ignorance, but is this a
>radiofrequency thing, or EMF? Should the electricians look at the wiring in the
>lab? Could there be a problem? It sure made it hard to do contamination
>surveys when just about anything electrical set off the GM detector.

Yes it can but the fields need to be fairly strong (I think). If there was a
strong source of UV around and assuming you have a very thin window on the
GM tube and assuming that some of the UV can get into the active volume,
this would easily cause it to go Burko (That is an Australian technical term).

Regards




                        Alex Zapantis
                        Radiation Safety Officer                               
                        Queensland University of Technology          
                        Health & Safety Section                             
                        Locked Bag No.2
                        Red Hill Qld 4059
                        AUSTRALIA

                        Ph     : 61 7 864 3566
                        fax     : 61 7 864 3993
                        email  : a.zapantis@qut.edu.au