Re: AW: GM response to neutrons?

[Doug Aitken <daitken@sugar-land.oilfield.slb.com>]

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

     

        

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