Harry Daghlian
Harry Daghlian | |
---|---|
![]() Daghlianc. 1944 | |
Born | Haroutune Krikor Daghlian Jr. May 4, 1921 |
Died | September 15, 1945 | (aged 24)
Cause of death | Acute radiation syndrome |
Resting place | Cedar Grove Cemetery |
Education | Massachusetts Institute of Technology Purdue University(BS) |
Occupation | Physicist |
![](https://upload.wikimedia.org/wikipedia/commons/thumb/a/a6/Herbert_Lehr_and_Haroutune_Krikor_Daghlian%2C_Jr._%28a.k.a._Harry_Daghlian%29_with_assembled_tamper_plug_containing_the_plutonium_pit_and_initiator_for_transport_to_the_shot_tower_on_13_July_1945._LA-Loading_components_%2834823045643%29_%28cropped%29.jpg/170px-thumbnail.jpg)
Haroutune Krikor Daghlian Jr.(May 4, 1921 – September 15, 1945) was an Americanphysicistwith theManhattan Project,which designed and produced theatomic bombsthat were used inWorld War II.He accidentallyirradiatedhimself on August 21, 1945, during acritical massexperiment at the remote Omega Site of theLos Alamos LaboratoryinNew Mexicoand died 25 days later from the resultantradiation poisoning.
Daghlian was irradiated as a result of acriticality accidentthat occurred when he accidentally dropped atungsten carbidebrick onto a 6.2 kgbomb coremade ofplutonium–gallium alloy.This core, subsequently nicknamed the "demon core",was later involved in the death of another physicist,Louis Slotin.
Early life and education
[edit]Haroutune Krikor Daghlian Jr., was born inWaterbury, Connecticut,on May 4, 1921, one of three children of Margaret Rose (néeCurrie) and Haroutune Krikor Daghlian. His father was an ethnicArmenianfromGaziantepin what is nowTurkey.He had a sister, Helen, and a brother, Edward.[1][2]Soon after his birth the family moved across state to the coastal town ofNew London, Connecticut.He was educated at Harbor Elementary School, where he played violin in the school orchestra, and atBulkeley High School.In 1938, at the age of 17, he entered theMassachusetts Institute of Technology,intending to study mathematics,[3]but became interested in physics, particularlyparticle physics,which was then emerging as an exciting new field. This interest led him to transfer to theWest Lafayette, Indiana,campus ofPurdue University,from which he graduated with aBachelor of Sciencedegree in 1942. He then commenced work on his doctorate, assistingMarshall Hollowaywith thecyclotrons.In 1944, while still a graduate student, he joinedOtto Frisch's Critical Assembly Group at theLos Alamos Laboratoryof theManhattan Project.[4][5]
Criticality accident and death
[edit]During an experiment on August 21, 1945, Daghlian was attempting to build aneutron reflectormanually by stacking a set of 4.4-kilogram (9.7 lb)tungsten carbidebricks in an incremental fashion around a plutonium core. The purpose of the neutron reflector was to reduce the mass required for the plutonium core to attain criticality. He was moving the final brick over the assembly, but neutron counters alerted Daghlian to the fact that the addition of that brick would render the systemsupercritical.As he withdrew his hand, he inadvertently dropped the brick onto the center of the assembly. Since the assembly was nearly in the critical state, the accidental addition of that brick caused the reaction to go immediately into theprompt criticalregion of neutronic behavior. This resulted in acriticality accident.[6][7]
Daghlian reacted immediately after dropping the brick and attempted to knock the brick off the assembly without success. He was forced to disassemble part of the tungsten-carbide pile in order to halt the reaction.[8]
Daghlian was estimated to have received a dose of 510rem(5.1Sv) ofneutron radiation,from a yield of 1016fissions.[6]Despite intensive medical care, he developed symptoms of severeradiation poisoning,and his sister and widowed mother were flown out to care for him.[3]He fell into a coma and died 25 days after the accident.[8][7]He was the first known fatality caused by a criticality accident. His body was returned to New London, where he was buried atCedar Grove Cemetery.[9]
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The two physicistsLouis Slotin(with sunglasses) and Harry Daghlian Jr. (seated middle) during the Trinity Test preparation in July 1945. Both physicists died following supercriticality accidents.
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The sphere ofplutoniumsurrounded by neutron-reflectingtungsten carbideblocks in a re-enactment of Daghlian's 1945 experiment[6]
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Harry K. Daghlian's blistered and burnt hand, photographed on August 30, 1945, after he received his fatal radiation dose. He died 16 days after this photo was taken.
Legacy
[edit]As a result of the incident, safety regulations for the project were scrutinized and revised. A special committee[specify]was established to review any similar experiments and recommend appropriate safety procedures. This change of procedures included needing a minimum of two people involved in such an experiment, using at least two instruments monitoring neutron intensities with audible alerts, and preparing a plan for operating methods and any contingencies that might occur during similar experiments.[10]Additionally, discussions and designs for remote-controlled test devices were initiated, eventually leading to the creation of theGodiva device.[citation needed]
These changes did not prevent another criticality accident from happening at Los Alamos the following year.Louis Slotin,a colleague of Daghlian's, was killed in 1946 while performing criticality tests on the same plutonium core.[6]After these two incidents it became known as the "demon core",[11]and all similar criticality experiments were halted until remote-controlled assembly devices were more fully developed and available.[10]
In 2000, the city of New London erected a memorial stone and flagpole in Calkins Park to honor Daghlian. His surname is misspelled "Daghiian" on the monument. The monument bears an inscription: "though not in uniform, he died in service to his country."[9]
References
[edit]- ^"Article clipped from The Day".The Day.September 19, 1945. p. 11.RetrievedJuly 1,2024.
- ^Howard, Lee."A death in the desert that 'Oppenheimer' ignored".theday.RetrievedJuly 1,2024.
- ^abBaumann, Paul (August 6, 1985)."NL man was 1st victim of atomic experiments".The Day.pp. 1, 4.RetrievedAugust 15,2015.
- ^"Harry Daghlian".Atomic Heritage Foundation.Archivedfrom the original on August 30, 2015.RetrievedAugust 15,2015.
- ^"Harry Daghlian, Jr., wins Purdue honor".The Day.April 1, 1941. p. 3.RetrievedAugust 15,2015.
- ^abcdMcLaughlin, Thomas P.; Monahan, Shean P.; Pruvost, Norman L.; Frolov, Vladimir V.; Ryazanov, Boris G.; Sviridov, Victor I. (May 2000),A Review of Criticality Accidents(PDF),Los Alamos, New Mexico:Los Alamos National Laboratory,pp. 74–75, LA-13638,archived(PDF)from the original on September 27, 2007,retrievedApril 21,2010
- ^abSullivan, Neil J. (2016).The Prometheus Bomb: The Manhattan Project and Government in the Dark.Lincoln:University of Nebraska Press.pp. 14–16.ISBN978-1-61234-890-2.RetrievedNovember 30,2021.
- ^abMiller, Richard L. (1991).Under the Cloud: The Decades of Nuclear Testing.The Woodlands, Texas:Two Sixty Press. pp.68, 69, 77.ISBN0-02-921620-6.
- ^abSlosberg, Steven (June 8, 2000)."A quiet victim of a horrific war he helped end".The Day.p. C1.RetrievedAugust 15,2015.
- ^abHayes, Daniel F. (August 1956).A Summary of Accidents and Incidents Involving Radiation in Atomic Energy Activities, June 1945 through December 1955(Report).Oak Ridge, Tennessee:U.S. Atomic Energy Commission.pp. 2–3.doi:10.2172/4343762.hdl:2027/mdp.39015095051879.OSTI4343762.TID-5360.RetrievedAugust 8,2015.
- ^Wellerstein, Alex."The Third Core's Revenge".Restricted data blog.Archivedfrom the original on April 7, 2014.RetrievedApril 4,2014.[unreliable source?][self-published source]
External links
[edit]![](https://upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/30px-Commons-logo.svg.png)
- 1921 births
- 1945 deaths
- Accidental deaths in New Mexico
- American nuclear physicists
- American people of Armenian descent
- Armenian physicists
- Burials at Cedar Grove Cemetery (New London, Connecticut)
- Deaths from laboratory accidents
- Manhattan Project people
- People from Los Alamos, New Mexico
- People from Waterbury, Connecticut
- People from New London, Connecticut
- Plutonium
- Purdue University alumni
- Deaths by acute radiation syndrome
- 20th-century American physicists