Re: Welcome to California(

[AndrewsJP@AOL.COM]

In a message dated 6/2/02 9:38:42 PM Pacific Daylight Time, kerrembaev@yahoo.com writes:



> Have you tried?:
>
>
> 1. To estimate activity distribution by driling
>
> just a "few" holes.
>
>
> 2. To establish correlation Depth vs Absorption
>
> (including self absorption) in the soil /
>
> Shielding from the soil.
>
>
> 3.It could safe some money.... 
>
>
> I know it can be done "easily" in the laboratory
>
> set up, I was wondering if a some one has tried
>
> that for the large areas monitoring....


I have done it two ways with interesting results.  The first was depth monitoring for radium near the old US Radium facility in New Jersey.  In that case we monitored the profile of the distribution of gamma activity in boreholes that were designed to penetrate through the deposited material in the dump areas.  My finding was that the data was not reproducable because most of it was from radon gas finding its way through the coal ash that was also dumped in the same area.  EPA management on the site would not permit us to use the new GeLi detectors newly available because it was not in our contract so we could not isolate the 0.184 MeV gamma line from the radium.  The reports ultimately were used as if the total gamma radiation was from local radium, not just radon.  Boreholes allowed to air for a day or more would 'dry up' as the radon escaped and would not produce the same results at a later time.  Production and the plan, however, requ!

ired the holes to be drilled, monitored, and filled with clay very rapidly.  My lesson was to not use this for radium.  The contractors lesson was to use the data to dig up the entire community.


On another job, we monitored for thorium spilled on the ground by sampling extensively.  To simplify this work, we began to use a bulb planting tool to make a nice hole in the ground, then measure the spectrum in the hole with a 2x2 NaI(Tl) detector.  This data was quickly translated into activity concentrations and permitted rapid cleanup of the local contamination without waiting for extended sampling turnaround times.  Sampling was used to verify the in-situ measurements after cleanup was completed.  


John Andrews

Knoxville, Tennessee