The Manhattan and Elsie Projects 99 



detonation points and enough symmetry in the time that you create an explo- 

 sive detonation wave driving toward the center which also has to be symmetri- 

 cal. This drives the whole mass inward at the same moment, and everything 

 arrives at the center. The assembly of this sphere in the center becomes a critical 

 mass and is helped some by the pressure generated by the explosives. Then the 

 whole critical mass starts a chain reaction which continues until it blows itself 

 apart. 



You mentioned people from Dahlgren going to other installations and working on the 

 Manhattan Project. Were you one of these? 



No. There were several times when people were called out of Dahlgren, and 

 one was when the determination was made by the government to deploy atomic 

 weapons. After the war was over, a large number of people from Dahlgren 

 went to observe the atomic tests in the Pacific where arrays of naval ships were 

 set up and atomic devices were exploded both under the water and above the 

 ships. These people then determined the damage to the ships to see how they 

 would survive. Also, Dahlgren people were sent to Japan and Germany after 

 the war to take a look at what was left of their armament and analyze how their 

 weapons and armor differed from ours. A fairly large number of people from 

 Dahlgren went on those projects. 



Admiral Ashworth was the bombardier for the second atomic bomb dropped onfapan. He 

 was Senior Aviator at Dahlgren in 1944. Did he have anything to do with the Manhattan 

 Project at that time? 



He probably had something to do with the shapes that were dropped from 

 the aircraft on our bombing ranges. He was Head of the Aviation Armament 

 Department, and they took care of all this. 



Can you describe the "Sewer Pipe" bomb addressed at Dahlgren? 



As I said previously, one of the ways to achieve an atomic reaction is by 

 assembling two subcritical masses in what is called a gun-type weapon. That was 

 what people referred to as a "Sewer Pipe" weapon. I think only one has ever 

 been detonated, and that was the first one in Japan. But the Navy — and I think 

 the Navy is probably the only activity which has undertaken development of 

 atomic weapons outside the Sandia Corporation and the Los Alamos and 

 Livermore Laboratories — in the late 1940's and early 1950's undertook the 

 design and development of two bombs. The first one was called the MARK 8 

 and the second was an improved version of the MARK 8 called the MARK 91. 

 These were gun-type weapons, and they were designed to penetrate hard 

 targets and detonate underground. Dahlgren became the primary test and 



