survey meter recommendation -Reply

[FRAMEP@ORAU.GOV]

John Nicholson wrote:

>I am looking for a recommendation for a rugged, hand held survey
>meter to be used to check scrap metal parts for NORM contamination.
>I would prefer a micro R readout but it is not essential. I am
>considering some Ludlem (models 9, 17, and 19) and Victoreen
>(models 450, 450B and 450P) meters. I would appreciate any
>recommendations on these or other similar meters. Please contact me
directly.

John:

Just a few thoughts, not suggestions. 

1. The upper range of the instrument might be a problem. You might
need to make a measurement above a couple of mR/hr and many NaI uR
meters cannot do this.
2. At some time you might want to pinpoint the contamination e.g.
scale inside a pipe or other awkward place to reach. A ratemeter or
ratemeter-scaler combo connected to a probe (e.g. side window GM/
ZnS/NaI) might allow you to do this. The conventional uR or urem
meter will not because the detector is fixed inside a large
instrument case. Also, you can use the same ratemeter with a variety
of probes - cheaper than having to buy several complete detector
systems. 
3. If I'm looking for contamination, as opposed to making a
measurement at a specific point, I like to have an audio output -its
much easier to locate contamination by sound than watching a needle
bounce around. Better still to have headphones - you may want to
survey in a noisy area or you might not want someone "listening in". 
4. Ion chambers typically won't have audio and are slow to respond
making them unsuitable , in many cases, for contamination surveys.
Can be great for measurements though.

I didn't respond directly because this kind of discussion can provide
everyone with useful info. Also, with it posted on the list, people
won't waste time sending you the same answer.

Best wishes

Paul Frame
Oak Ridge Associated Universities
framep@orau.gov