(14) 
to this operation. (The radioactivity levels at which the gamma, 
well logging instruments operate is many orders of magnitude higher 
than natural radioactivity in the ocean. Generally in the well work, 
they irradiate the side wall of the well with a particular radiation 
and then look for a certain reaction. They do not have to work at 
low Pesiey The instrument is pressure packed with grease to make 
it rather solid on the inside; it can now operate under about 2000 ft. 
of water. It is connected by a shielded, mono-conductor having a 
woven stainless steel jacket to an Esterline Angus Recorder which 
makes the records. Power is sent to the instrument circuit from the 
surface and the signal comes back up the same aneea 
Probing Problem: The depth of the well logging instrument is 
measured by length of cable out on a spool. In the sea application 
this method would tell only how much cable is out and not where the 
instrument is LO is: i.e with 20,000 feet of cable out the 
location of the instrument in the lowest 200 to 300 ft. would be 
i The waste concentration is expected to vary with depth 
as well as spread out eee 
An echo sounder device on the detector may help pinpoint the 
location. The Woods Hole Institution has operated echo sounders 
at 2000 feet depths ard are continually striving for greater Anse 
However, if an echo sounder is put on in an attempt to work from the 
bottom, there would still be a difficult cable problem because the 
echo sounder has to be driven. Ail the instruments together must 
also have a very small physical bulk; otherwise the cable will drift 
(16) 
laterally to one side of the ship. 
«68- 
