Figure 3. Packet of gold-tagged sand. When the water 

 soluble packaging material dissolves (approximately 30 

 seconds) the tagged sand is free to move as individual 

 particles responding to waves and currents. 



Based on experimental results of Pirie (1965), who studied the settling 

 rates of granule- and pebble-sized particles (2 to 64 millimeters), the 

 packets containing the gold-tagged sand would have a settling velocity 

 of approximately 25 centimeters per second. At this rate the packets 

 would reach the ocean bottom in water depths up to about 25 feet before 

 dissolving and releasing the sand to move under the influence of ambient 

 forces on the bottom. Nevertheless, to ensure more rapid settling, the 

 packets were weighted with several lead pellets. Also, dissolving time 

 can be lengthened by using thicker plastic bags. 



The use of sand tagged with gold, which has a higher energy gamma 

 photon than xenon, required design of another injection device by ORNL 

 to effect safe and efficient handling. The dispensing device described 

 by ORNL (Case, et al., in preparation) is shown in Figure 4, rigged for 

 operation just prior to injecting the sand. The same container, with 

 different end plates, is used to ship the tagged sand by common carrier 

 from Oak Ridge to the study site. 



3. Detector and Onboard Data Collection System 



No significant changes have been made to the towed ball-like 

 detector vehicle (Figure 5) as previously described (Acree, et al . , 1969 



