Harry Daghlian
Harry K. Daghlian, Jr. | |
|---|---|
 | |
| Born | Haroutune Krikor Daghlian, Jr. May 4, 1921 |
| Died | September 15, 1945 (age 24) |
| Cause of death | Radiation poisoning |
| Education | Bachelor of Science |
| Alma mater | Purdue University |
| Occupation | Physicist |
Haroutune Krikor Daghlian, Jr. (May 4, 1921 – September 15, 1945) was an Armenian-American physicist with the Manhattan Project who accidentally irradiated himself on August 21, 1945, during a critical mass experiment at the remote Omega Site facility at Los Alamos National Laboratory in New Mexico, resulting in his death 25 days later.
Daghlian was irradiated as a result of a criticality accident that occurred when he accidentally dropped a tungsten carbide brick onto a 6.2 kg delta phase plutonium bomb core.[1] This core, available at the close of World War II and later nicknamed the "Demon core", also resulted in the death of Louis Slotin in a similar accident, and was used in the ABLE detonation, during the Crossroads series of nuclear weapon testing.[2]
Early life
Daghlian was the first of three children born to Margaret Rose Currie and Haroutune Krikor Daghlian. Soon after his birth in Waterbury, Connecticut, the family moved across state to the coastal town of New London.[3]
The criticality accident
In the experiment, Daghlian was attempting to build a neutron reflector by manually stacking a series of 4.4 kg tungsten carbide bricks in an incremental fashion around the plutonium core. The purpose of the neutron reflector was to reduce the mass required for the plutonium core to attain criticality.
As he was moving the final brick over the assembly, neutron counters alerted Daghlian to the fact that the addition of this brick would render the system supercritical. As he withdrew his hand, he accidentally dropped the brick onto the center of the assembly. Since the assembly was nearly in the critical state, the accidental addition of the last brick caused the reaction to go immediately into the prompt critical region of supercritical behavior. This resulted in a power excursion.
Daghlian panicked immediately after dropping the brick and attempted to knock off the brick without success; he was forced to partially disassemble the tungsten-carbide pile to halt the reaction.[2] Daghlian was estimated to have received a dose of 510 rem (5.1 Sv) of neutron radiation, from a yield of 1016 fissions.[1] He died 25 days later from acute radiation poisoning.[2]
Legacy
As a result of the incident, safety regulations for the project were scrutinized and revised. A special committee was established to review any similar experiments and recommend appropriate safety procedures. These procedures included needing a minimum of two people involved in such an experiment; at least two instruments monitoring neutron intensities, each with audible alerts; and a prepared plan for operating methods and any contingencies which may occur during an experiment. Additionally, discussions and designs for remote-controlled test devices were initiated, which eventually led to the creation of the Godiva device.[4] These changes however did not prevent another criticality accident at Los Alamos, when Louis Slotin was killed in 1946 while performing criticality tests on the same core that killed Daghlian.
The incident was later fictionalized in the 1995 book Los Alamos by Joseph Kanon.
Spike's 1000 Ways to Die also had a fictionalized version of the accident with present-day terrorists recreating the experiment and accident. See Season 3, Episode 36: Sudden Death, Way to die #692:Gone Fission/WWM'D.
Daghlian was memorialized on May 20, 2000, by the city of New London, Connecticut, with the erection of a memorial stone and flagpole in Calkins Park.[3]
See also
References
- ^ a b c McLaughlin, Thomas P.; Monahan, Shean P.; Pruvost, Norman L.; Frolov, Vladimir V.; Ryazanov, Boris G.; Sviridov, Victor I. (2000), A Review of Criticality Accidents (PDF), Los Alamos, New Mexico: Los Alamos National Laboratory, pp. 74–75, LA-13638, retrieved 2010-04-12
{{citation}}: Unknown parameter|month=ignored (help) - ^ a b c Miller, Richard L. (1991). Under the Cloud: The Decades of Nuclear Testing. The Woodlands, Texas: Two Sixty Press. pp. 68, 69, 77. ISBN 0029216206.
- ^ a b Dion, Arnold S., Harry Daghlian: America's first peacetime atom bomb fatality, retrieved 2010-04-13
- ^ Hayes, Daniel F. (1956), A Summary of Accidents and Incidents Involving Radiation in Atomic Energy Activities, June 1945 through December 1955 (PDF), Oak Ridge, Tennessee: U.S. Atomic Energy Commission, pp. 2–3, TID-5360, retrieved 2010-04-12
{{citation}}: Unknown parameter|month=ignored (help)