Underwater Survey Instrument

[Glen.Vickers@ucm.com]

Underwater survey instruments used in a power plant setting.

1.  Electronic dosimeters (ED) in an underwater enclosure.  Need to prepare
multiple dosimeters and associated commo interfaces.  Must source check EDs
for use as survey meters.  The rate calculation mechanism for EDs which
looks for numbers of pulses within a prescribed time frame often times
results in significant deviations in rate output.  The time period is often
times quite short, which naturally results in a greater deviation of
results.  EDs often times only transmit once every so often, so when you
combine the rate deviation and the infrequent update, you wind up with a
survey process of more difficulty and complexity  than that of a traditional
underwater survey meter.  Underwater enclosures are typically large an
bulky.  After the dive, you will typically have to spend a good bit of time
after the dive to decon the underwater enclosure to retrieve your EDs and
restore battery power to the EDs.

2.  Eberline RO-7, works but is larger than MGP Amp-100.  More difficult to
calibrate the different detectors and it doesn't have a telemetry option
like the MGP Amp-100.

3.  MGP Amp-100 would probably be the underwater survey meter of choice.  It
is a single upper range GM.  I believe the vendor-prescribed lower limit is
5 mrem/hr.  Most dive operations really are in the lower ranges, so I
personally would like to see a lower range GM tube added, but still I don't
know of another underwater survey instrument that is so easy to use or
performs so well in real field use.  The probe and meter box are very
compact.  Relatively cheap and proven reliable in many applications.
Telemetry options can be used which are the same as that of the diver's ED.
You can watch the survey instrument response and the divers ED response on
the same computer screen.  This instrument is an all-around good area
monitor or survey instrument.  I recognize there are energy response
differences between the GM survey instrument and the semiconductor diodes of
many of todays EDs, but I still believe the Amp-100 is the best that I've
been exposed to.


glen

glen.vickers@ucm.com <mailto:glen.vickers@ucm.com> 
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