Re: ionization chambers, micro rem meters, etc.

[Chris Davey <cdavey@med.phys.ualberta.ca>]

On Tue, 12 Nov 1996, Jennifer Wilson wrote: 
> I am in a quandry as to what survey meter is appropriate for my needs.  I 
> (snip)                       Can any one tell me what they use and which 
> instruments serve them best for assessing field strengths?  I am leaning 
> towards a Victoreen 450P or 450CHP.  Any feedback on these instruments?
> Thank you for any assistance you can provide.
> 				Sincerely,
> 				Jennifer Wilson
> 				University of Northern B.C.

We bought a set of 450Ps about three years ago (nine in all) and have 
found them to be easy to use and reliable.  They do take a minute or so 
to warm up enough to be useful at the 250 microR/hr range, but drop to 
read below 100 microR/hr by that time.  In about 5 minutes, they read 
'true' background at about 10 microR/hr (here in Edmonton).  The 
pressurized ionization chamber seems to hold its pressure well; we have 
managed to successfully calibrate these meters each year.  I particularly 
like them because we have linear accelerators here, and the pulsed (micro 
seconds on, milli seconds off) nature of this emanation does not affect 
their accuracy.

I also like them because they are useful in teaching - I can demonstrate 
background radiation during a lecture, and show the students after the 
lecture how much radiation they accumulated whilst the lecture was in 
progress.

I don't know of any other manufacturer who makes a instrument that has 
these characteristics.

Regards,

Chris Davey

RSO  Cross Cancer Institute  11560 University Avenue
        Edmonton   Alberta   Canada  T5R 3P4
        (403)432-8616   fax 432-8615    email cdavey@med.phys.ualberta.ca