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Re: AW: GM response to neutrons?



At 06:18 PM 1/29/2003 -0800, Ted de Castro wrote:
Well logging AmBe sources are only 50 mCi and about 1/4 mR/hr at a meter
- NOT inside the logging device - that is the reading in the open for
the bare source.

Generally the AmBe sources used for most (neutron porosity) well logging are in the range 5-15 Ci (based on alpha disintegrations). However, the neutron yield equivalent activity is indeed probably equivalent to about what you state.

Dosimeter is required if you are likely to exceed 10% of the permitted
dose.  That's 2000 hr per year at 1 meter from the source!  That's the
whole working year at 1 meter from the source!

I can see why the neutron meter and dosimeter might not be required
around one such device in the field - but be required back in the shop
where there may be several.

I think this question was answered: we of course carry both gamma and neutron dosimeters. The original question was regarding survey meters.

Regards
Doug



Doug Aitken             Schlumberger Drilling and Measurements QHSE Advisor                      
Phone (Sugarland):      281 285-8009
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