Profile: Harry K. Daghlian, Jr.

Harry K. Daghlian, Jr.
1921 - 1945

Harry K. Daghlian, Jr. was born in Waterbury, Connecticut, the first child of Haroutune Krikor Daghlian and Margaret Rose Daghlian. Harry grew fond of science and mathematics, especially since his father was an X-ray technician and his uncle a professor of physics and astronomy. He graduated first in mathematics from his high school and graduated from Purdue University with a Bachelor of Science degree. Robert Oppenheimer recruited Harry and four of his colleagues for work on the atomic bomb project in 1943 and he would begin working there in the spring of 1944, after completing required coursework back home.

On 21 August, 1945, Daghlian was involved with a series of experiments concerning the critical masses of radioactive Plutonium 239. Critical mass is the amount of material needed to sustain a chain reaction, which is essential to atomic bombs. In his final experiment, Harry was dealing with tungsten carbide blocks, which surround a radioactive core and help reduce the amount of material needed to sustain a chain reaction. As he stacked the blocks to determine the amount needed for criticality, he accidentally dropped one of them directly over the core, initiating a reaction. Massive doses of radiation were released from this event, while Harry averted an even greater disaster by knocking the blocks off with his hand, all the while receiving even more radiation. He was immediately taken to a hospital and treated for over 26 days, but to no avail. Daghlian died at 4:30 PM on Saturday, September 15, 1945. Harry K. Daghlian, Jr. became the first American casualty of the atomic age. On May 20, 2000, Daghlian was memorialized by the city of New London, Connecticut.

Did you know?
This radioactive Plutonium core used by Daghlian was probably the core for the next intended atomic bomb to be used on Japan, though it was never dropped. The second of the two bombs used on the city of Nagasaki used a similar Plutonium core, though it was dropped days earlier on August 9, 1945.

If you would like to learn more, here are some suggested sources:
Harry K. Daghlian, Jr. Website
Harry K. Daghlian, Jr. on Wikipedia
Fat Man on Wikipedia