Little Boy (English Wikipedia)

The critical mass of any given nuclear system is not simply a matter of mass — it is a more complex function of the mass, its geometry, and properties like neutron reflection, among other things. As an illustrative example, the "bare sphere" critical mass of 70%-enriched uranium is 87.2 kilograms (192 lb), but with a 5 centimetres (2.0 in) beryllium neutron reflector, it drops to 36.5 kilograms (80 lb), and with a 10 centimetres (3.9 in) beryllium reflector, it drops to 23.7 kilograms (52 lb). Glaser, Alexander (2006). "On the Proliferation Potential of Uranium Fuel for Research Reactors at Various Enrichment Levels". Science and Global Security. 14 (1): 1–24. Bibcode:2006S&GS...14....1G. doi:10.1080/08929880600620542. So while the 38.53 kilograms (84.9 lb), 80%-enriched, cylindrical "projectile" was an insufficient amount of enriched uranium to be a "bare sphere" critical mass, inside of a neutron-reflecting system it could potentially be dangerously close to criticality even prior to weapon assembly, or just prior to full assembly. After weapon assembly, the 64.2 kilograms (142 lb) 80%-enriched material, in a solid cylinder and encased in a neutron-reflecting tungsten tamper, would have composed more than one critical mass.
Richardson RR 2009. Richardson, David; et al. (September 2009). "Ionizing Radiation and Leukemia Mortality among Japanese Atomic Bomb Survivors, 1950–2000". Radiation Research. 172 (3): 368–382. Bibcode:2009RadR..172..368R. doi:10.1667/RR1801.1. PMID 19708786. S2CID 12463437.
Putnam, F. W. (12 May 1998). "The Atomic Bomb Casualty Commission in retrospect". Proceedings of the National Academy of Sciences of the United States of America. 95 (10): 5426–5431. Bibcode:1998PNAS...95.5426P. doi:10.1073/pnas.95.10.5426. PMC 33857. PMID 9576898.

anesi.com (Global: low place; English: low place)

D'Olier 1946, pp. 22–25. D'Olier, Franklin, ed. (1946). United States Strategic Bombing Survey, Summary Report (Pacific War). Washington: United States Government Printing Office. Retrieved 6 November 2013. This report can also be found here.
D'Olier 1946, p. 24. D'Olier, Franklin, ed. (1946). United States Strategic Bombing Survey, Summary Report (Pacific War). Washington: United States Government Printing Office. Retrieved 6 November 2013. This report can also be found here.

archive.org (Global: 6^th place; English: 6^th place)

Serber & Crease 1998, p. 104. Serber, Robert; Crease, Robert P. (1998). Peace & War: Reminiscences of a Life on the Frontiers of Science. New York: Columbia University Press. ISBN 978-0231105460. OCLC 37631186.
Rhodes 1986, p. 541. Rhodes, Richard (1986). The Making of the Atomic Bomb. New York: Simon & Schuster. ISBN 0-684-81378-5. OCLC 13793436.
The "Mark" nomenclature did not become standardized until the postwar period. Some wartime documents refer to "Mark I" and "Mark II" as different gun-type weapons, or "Mark II" and "Mark III" as referring to non-lens implosion concepts that were pursued until the spring of 1945 (with "Mark IV" being the lensed Fat Man design). Eventually the "Mark I" was used exclusively for Little Boy, and "Mark III" for Fat Man. See e.g., Hewlett & Anderson 1962, pp. 251–252, Hansen 1995a, p. 65, and discussion of nonlens program in Hoddeson et al. 1993, pp. 300, 312. Hewlett, Richard G.; Anderson, Oscar E. (1962). The New World, 1939–1946 (PDF). Vol. I: A History of the United States Atomic Energy Commission. University Park, Penn.: Pennsylvania State University Press. LCCN 62-14633. OCLC 637004643. Retrieved 26 March 2013. Reprint (1990): ISBN 0-520-07186-7. Hansen, Chuck (1995a). Volume VII: The Development of US Nuclear Weapons. Swords of Armageddon: US Nuclear Weapons Development since 1945. Sunnyvale, California: Chuckelea Publications. ISBN 978-0-9791915-7-2. OCLC 231585284. Hoddeson, Lillian; Henriksen, Paul W.; Meade, Roger A.; Westfall, Catherine L. (1993). Critical Assembly: A Technical History of Los Alamos During the Oppenheimer Years, 1943–1945. New York: Cambridge University Press. ISBN 0-521-44132-3. OCLC 26764320.
Hoddeson et al. 1993, p. 419. Hoddeson, Lillian; Henriksen, Paul W.; Meade, Roger A.; Westfall, Catherine L. (1993). Critical Assembly: A Technical History of Los Alamos During the Oppenheimer Years, 1943–1945. New York: Cambridge University Press. ISBN 0-521-44132-3. OCLC 26764320.
Groves 1962, p. 260. Groves, Leslie (1962). Now It Can Be Told: The Story of the Manhattan Project. New York: Harper. OCLC 537684.
Hoddeson et al. 1993, pp. 42–44. Hoddeson, Lillian; Henriksen, Paul W.; Meade, Roger A.; Westfall, Catherine L. (1993). Critical Assembly: A Technical History of Los Alamos During the Oppenheimer Years, 1943–1945. New York: Cambridge University Press. ISBN 0-521-44132-3. OCLC 26764320.
Hoddeson et al. 1993, pp. 67, 75. Hoddeson, Lillian; Henriksen, Paul W.; Meade, Roger A.; Westfall, Catherine L. (1993). Critical Assembly: A Technical History of Los Alamos During the Oppenheimer Years, 1943–1945. New York: Cambridge University Press. ISBN 0-521-44132-3. OCLC 26764320.
Groves 1962, pp. 162–163. Groves, Leslie (1962). Now It Can Be Told: The Story of the Manhattan Project. New York: Harper. OCLC 537684.
Hoddeson et al. 1993, pp. 82–84. Hoddeson, Lillian; Henriksen, Paul W.; Meade, Roger A.; Westfall, Catherine L. (1993). Critical Assembly: A Technical History of Los Alamos During the Oppenheimer Years, 1943–1945. New York: Cambridge University Press. ISBN 0-521-44132-3. OCLC 26764320.
Hoddeson et al. 1993, pp. 87, 114. Hoddeson, Lillian; Henriksen, Paul W.; Meade, Roger A.; Westfall, Catherine L. (1993). Critical Assembly: A Technical History of Los Alamos During the Oppenheimer Years, 1943–1945. New York: Cambridge University Press. ISBN 0-521-44132-3. OCLC 26764320.
Hoddeson et al. 1993, p. 228. Hoddeson, Lillian; Henriksen, Paul W.; Meade, Roger A.; Westfall, Catherine L. (1993). Critical Assembly: A Technical History of Los Alamos During the Oppenheimer Years, 1943–1945. New York: Cambridge University Press. ISBN 0-521-44132-3. OCLC 26764320.
Hoddeson et al. 1993, pp. 245–249. Hoddeson, Lillian; Henriksen, Paul W.; Meade, Roger A.; Westfall, Catherine L. (1993). Critical Assembly: A Technical History of Los Alamos During the Oppenheimer Years, 1943–1945. New York: Cambridge University Press. ISBN 0-521-44132-3. OCLC 26764320.
Hoddeson et al. 1993, p. 257. Hoddeson, Lillian; Henriksen, Paul W.; Meade, Roger A.; Westfall, Catherine L. (1993). Critical Assembly: A Technical History of Los Alamos During the Oppenheimer Years, 1943–1945. New York: Cambridge University Press. ISBN 0-521-44132-3. OCLC 26764320.
Hoddeson et al. 1993, p. 262. Hoddeson, Lillian; Henriksen, Paul W.; Meade, Roger A.; Westfall, Catherine L. (1993). Critical Assembly: A Technical History of Los Alamos During the Oppenheimer Years, 1943–1945. New York: Cambridge University Press. ISBN 0-521-44132-3. OCLC 26764320.
Hoddeson et al. 1993, p. 265. Hoddeson, Lillian; Henriksen, Paul W.; Meade, Roger A.; Westfall, Catherine L. (1993). Critical Assembly: A Technical History of Los Alamos During the Oppenheimer Years, 1943–1945. New York: Cambridge University Press. ISBN 0-521-44132-3. OCLC 26764320.
Hoddeson et al. 1993, p. 293. Hoddeson, Lillian; Henriksen, Paul W.; Meade, Roger A.; Westfall, Catherine L. (1993). Critical Assembly: A Technical History of Los Alamos During the Oppenheimer Years, 1943–1945. New York: Cambridge University Press. ISBN 0-521-44132-3. OCLC 26764320.
Hoddeson et al. 1993, p. 333. Hoddeson, Lillian; Henriksen, Paul W.; Meade, Roger A.; Westfall, Catherine L. (1993). Critical Assembly: A Technical History of Los Alamos During the Oppenheimer Years, 1943–1945. New York: Cambridge University Press. ISBN 0-521-44132-3. OCLC 26764320.
Gosling 1999, p. 51. Gosling, F. G. (1999). The Manhattan Project: Making the Atomic Bomb. Diane Publishing. ISBN 978-0-7881-7880-1.
Bernstein 2007, p. 133. Bernstein, Jeremy (2007). Nuclear Weapons: What You Need to Know. Cambridge University Press. ISBN 978-0-521-88408-2.
Hoddeson et al. 1993, pp. 263–265. Hoddeson, Lillian; Henriksen, Paul W.; Meade, Roger A.; Westfall, Catherine L. (1993). Critical Assembly: A Technical History of Los Alamos During the Oppenheimer Years, 1943–1945. New York: Cambridge University Press. ISBN 0-521-44132-3. OCLC 26764320.
Monk 2012, pp. 409–410. Monk, Ray (2012). Robert Oppenheimer: A Life Inside the Center. New York; Toronto: Doubleday. ISBN 978-0-385-50407-2.
Groves 1962, p. 269. Groves, Leslie (1962). Now It Can Be Told: The Story of the Manhattan Project. New York: Harper. OCLC 537684.
Hoddeson et al. 1993, p. 393. Hoddeson, Lillian; Henriksen, Paul W.; Meade, Roger A.; Westfall, Catherine L. (1993). Critical Assembly: A Technical History of Los Alamos During the Oppenheimer Years, 1943–1945. New York: Cambridge University Press. ISBN 0-521-44132-3. OCLC 26764320.

atomicarchive.com (Global: low place; English: low place)

The Atomic Bombings of Hiroshima and Nagasaki, 1946, p. 14. The Atomic Bombings of Hiroshima and Nagasaki (PDF) (Report). The Manhattan Engineer District. 29 June 1946. Archived from the original (PDF) on 6 April 2012. Retrieved 6 November 2013. This report can also be found here and here.
The Atomic Bombings of Hiroshima and Nagasaki, 1946, pp. 21–23. The Atomic Bombings of Hiroshima and Nagasaki (PDF) (Report). The Manhattan Engineer District. 29 June 1946. Archived from the original (PDF) on 6 April 2012. Retrieved 6 November 2013. This report can also be found here and here.
The Atomic Bombings of Hiroshima and Nagasaki, 1946, p. 21. The Atomic Bombings of Hiroshima and Nagasaki (PDF) (Report). The Manhattan Engineer District. 29 June 1946. Archived from the original (PDF) on 6 April 2012. Retrieved 6 November 2013. This report can also be found here and here.

books.google.com (Global: 3^rd place; English: 3^rd place)

Diacon 1984, p. 18. Diacon, Diane (1984). Residential Housing and Nuclear Attack. London: Croom Helm. ISBN 978-0-7099-0868-5.

city.hiroshima.jp (Global: low place; English: low place)

pcf.city.hiroshima.jp

Human Shadow Etched in Stone. "Human Shadow Etched in Stone". Photographic Display. Hiroshima Peace Memorial Museum. Archived from the original on 20 July 2021. Retrieved 6 November 2013.

csu.edu.au (Global: low place; English: low place)

marshall.csu.edu.au

D'Olier 1946, pp. 22–25. D'Olier, Franklin, ed. (1946). United States Strategic Bombing Survey, Summary Report (Pacific War). Washington: United States Government Printing Office. Retrieved 6 November 2013. This report can also be found here.
D'Olier 1946, p. 24. D'Olier, Franklin, ed. (1946). United States Strategic Bombing Survey, Summary Report (Pacific War). Washington: United States Government Printing Office. Retrieved 6 November 2013. This report can also be found here.

doi.org (Global: 2^nd place; English: 2^nd place)

The critical mass of any given nuclear system is not simply a matter of mass — it is a more complex function of the mass, its geometry, and properties like neutron reflection, among other things. As an illustrative example, the "bare sphere" critical mass of 70%-enriched uranium is 87.2 kilograms (192 lb), but with a 5 centimetres (2.0 in) beryllium neutron reflector, it drops to 36.5 kilograms (80 lb), and with a 10 centimetres (3.9 in) beryllium reflector, it drops to 23.7 kilograms (52 lb). Glaser, Alexander (2006). "On the Proliferation Potential of Uranium Fuel for Research Reactors at Various Enrichment Levels". Science and Global Security. 14 (1): 1–24. Bibcode:2006S&GS...14....1G. doi:10.1080/08929880600620542. So while the 38.53 kilograms (84.9 lb), 80%-enriched, cylindrical "projectile" was an insufficient amount of enriched uranium to be a "bare sphere" critical mass, inside of a neutron-reflecting system it could potentially be dangerously close to criticality even prior to weapon assembly, or just prior to full assembly. After weapon assembly, the 64.2 kilograms (142 lb) 80%-enriched material, in a solid cylinder and encased in a neutron-reflecting tungsten tamper, would have composed more than one critical mass.
Richardson RR 2009. Richardson, David; et al. (September 2009). "Ionizing Radiation and Leukemia Mortality among Japanese Atomic Bomb Survivors, 1950–2000". Radiation Research. 172 (3): 368–382. Bibcode:2009RadR..172..368R. doi:10.1667/RR1801.1. PMID 19708786. S2CID 12463437.
Izumi BJC 2003. Izumi, S.; Koyama, K.; Soda, M.; Suyama, A. (November 2003). "Cancer incidence in children and young adults did not increase relative to parental exposure to atomic bombs". British Journal of Cancer. 89 (9): 1709–1713. doi:10.1038/sj.bjc.6601322. PMC 2394417. PMID 14583774.
Izumi IJC 2003. Izumi, S.; Suyama, A.; Koyama, K. (November 2003). "Radiation-related mortality among offspring of atomic bomb survivors: a half-century of follow-up". International Journal of Cancer. 107 (2): 292–297. doi:10.1002/ijc.11400. PMID 12949810. S2CID 23902907.
Putnam, F. W. (12 May 1998). "The Atomic Bomb Casualty Commission in retrospect". Proceedings of the National Academy of Sciences of the United States of America. 95 (10): 5426–5431. Bibcode:1998PNAS...95.5426P. doi:10.1073/pnas.95.10.5426. PMC 33857. PMID 9576898.

fas.org (Global: 730^th place; English: 519^th place)

Nuclear Weapon Thermal Effects 1998. "Nuclear Weapon Thermal Effects". Special Weapons Primer, Weapons of Mass Destruction. Federation of American Scientists. 1998. Archived from the original on 22 April 2013. Retrieved 5 November 2013.

fourmilab.ch (Global: low place; English: low place)

Glasstone & Dolan 1977, p. 12. Glasstone, Samuel; Dolan, Philip J. (1977). The Effects of Nuclear Weapons, Third Edition. United States: United States Department of Defense and United States Department of Energy. ISBN 978-1603220163.
Glasstone & Dolan 1977, p. Nuclear Bomb Effects Computer. Glasstone, Samuel; Dolan, Philip J. (1977). The Effects of Nuclear Weapons, Third Edition. United States: United States Department of Defense and United States Department of Energy. ISBN 978-1603220163.
Glasstone & Dolan 1977, p. 1. Glasstone, Samuel; Dolan, Philip J. (1977). The Effects of Nuclear Weapons, Third Edition. United States: United States Department of Defense and United States Department of Energy. ISBN 978-1603220163.
Glasstone & Dolan 1977, pp. 300, 301. Glasstone, Samuel; Dolan, Philip J. (1977). The Effects of Nuclear Weapons, Third Edition. United States: United States Department of Defense and United States Department of Energy. ISBN 978-1603220163.
Glasstone & Dolan 1977, p. 179. Glasstone, Samuel; Dolan, Philip J. (1977). The Effects of Nuclear Weapons, Third Edition. United States: United States Department of Defense and United States Department of Energy. ISBN 978-1603220163.
Glasstone & Dolan 1977, pp. 300–304. Glasstone, Samuel; Dolan, Philip J. (1977). The Effects of Nuclear Weapons, Third Edition. United States: United States Department of Defense and United States Department of Energy. ISBN 978-1603220163.
Glasstone & Dolan 1977, p. 304. Glasstone, Samuel; Dolan, Philip J. (1977). The Effects of Nuclear Weapons, Third Edition. United States: United States Department of Defense and United States Department of Energy. ISBN 978-1603220163.
Glasstone & Dolan 1977, pp. Chapter VIII and the 'Nuclear Bomb Effects Computer'. Glasstone, Samuel; Dolan, Philip J. (1977). The Effects of Nuclear Weapons, Third Edition. United States: United States Department of Defense and United States Department of Energy. ISBN 978-1603220163.
Glasstone & Dolan 1977, pp. 545, 546. Glasstone, Samuel; Dolan, Philip J. (1977). The Effects of Nuclear Weapons, Third Edition. United States: United States Department of Defense and United States Department of Energy. ISBN 978-1603220163.
Glasstone & Dolan 1977, p. 101. Glasstone, Samuel; Dolan, Philip J. (1977). The Effects of Nuclear Weapons, Third Edition. United States: United States Department of Defense and United States Department of Energy. ISBN 978-1603220163.
These calculated numbers come from the NUKEMAP website, which uses the data and calculations from Glasstone & Dolan 1977, pp. 80–122. Glasstone, Samuel; Dolan, Philip J. (1977). The Effects of Nuclear Weapons, Third Edition. United States: United States Department of Defense and United States Department of Energy. ISBN 978-1603220163.

governmentattic.org (Global: low place; English: 6,646^th place)

The "Mark" nomenclature did not become standardized until the postwar period. Some wartime documents refer to "Mark I" and "Mark II" as different gun-type weapons, or "Mark II" and "Mark III" as referring to non-lens implosion concepts that were pursued until the spring of 1945 (with "Mark IV" being the lensed Fat Man design). Eventually the "Mark I" was used exclusively for Little Boy, and "Mark III" for Fat Man. See e.g., Hewlett & Anderson 1962, pp. 251–252, Hansen 1995a, p. 65, and discussion of nonlens program in Hoddeson et al. 1993, pp. 300, 312. Hewlett, Richard G.; Anderson, Oscar E. (1962). The New World, 1939–1946 (PDF). Vol. I: A History of the United States Atomic Energy Commission. University Park, Penn.: Pennsylvania State University Press. LCCN 62-14633. OCLC 637004643. Retrieved 26 March 2013. Reprint (1990): ISBN 0-520-07186-7. Hansen, Chuck (1995a). Volume VII: The Development of US Nuclear Weapons. Swords of Armageddon: US Nuclear Weapons Development since 1945. Sunnyvale, California: Chuckelea Publications. ISBN 978-0-9791915-7-2. OCLC 231585284. Hoddeson, Lillian; Henriksen, Paul W.; Meade, Roger A.; Westfall, Catherine L. (1993). Critical Assembly: A Technical History of Los Alamos During the Oppenheimer Years, 1943–1945. New York: Cambridge University Press. ISBN 0-521-44132-3. OCLC 26764320.

gutenberg.org (Global: 629^th place; English: 427^th place)

The Manhattan Engineer District (29 June 1946). "The Atomic Bombings of Hiroshima and Nagasaki". p. 3 – via Project Gutenberg.

ibiblio.org (Global: 1,093^rd place; English: 690^th place)

Craven & Cate 1983, pp. 722–723. Craven, W. F.; Cate, J. L., eds. (1983). The Pacific: Matterhorn to Nagasaki, June 1944 to August 1945. The Army Air Forces in World War II. Vol. 5. Washington, D.C.: Office of Air Force History. OCLC 9828710. Retrieved 28 March 2023.

lanl.gov (Global: 5,474^th place; English: 5,230^th place)

library.lanl.gov

Malik 1985, p. 1. Malik, John S. (1985). The yields of the Hiroshima and Nagasaki nuclear explosions (PDF) (Report). Los Alamos National Laboratory report. LA-8819. Retrieved 6 November 2013.
Malik 1985, pp. 18–20. Malik, John S. (1985). The yields of the Hiroshima and Nagasaki nuclear explosions (PDF) (Report). Los Alamos National Laboratory report. LA-8819. Retrieved 6 November 2013.
Malik 1985, p. 21. Malik, John S. (1985). The yields of the Hiroshima and Nagasaki nuclear explosions (PDF) (Report). Los Alamos National Laboratory report. LA-8819. Retrieved 6 November 2013.
Malik 1985, p. 16. Malik, John S. (1985). The yields of the Hiroshima and Nagasaki nuclear explosions (PDF) (Report). Los Alamos National Laboratory report. LA-8819. Retrieved 6 November 2013.

loc.gov (Global: 63^rd place; English: 47^th place)

lccn.loc.gov

The "Mark" nomenclature did not become standardized until the postwar period. Some wartime documents refer to "Mark I" and "Mark II" as different gun-type weapons, or "Mark II" and "Mark III" as referring to non-lens implosion concepts that were pursued until the spring of 1945 (with "Mark IV" being the lensed Fat Man design). Eventually the "Mark I" was used exclusively for Little Boy, and "Mark III" for Fat Man. See e.g., Hewlett & Anderson 1962, pp. 251–252, Hansen 1995a, p. 65, and discussion of nonlens program in Hoddeson et al. 1993, pp. 300, 312. Hewlett, Richard G.; Anderson, Oscar E. (1962). The New World, 1939–1946 (PDF). Vol. I: A History of the United States Atomic Energy Commission. University Park, Penn.: Pennsylvania State University Press. LCCN 62-14633. OCLC 637004643. Retrieved 26 March 2013. Reprint (1990): ISBN 0-520-07186-7. Hansen, Chuck (1995a). Volume VII: The Development of US Nuclear Weapons. Swords of Armageddon: US Nuclear Weapons Development since 1945. Sunnyvale, California: Chuckelea Publications. ISBN 978-0-9791915-7-2. OCLC 231585284. Hoddeson, Lillian; Henriksen, Paul W.; Meade, Roger A.; Westfall, Catherine L. (1993). Critical Assembly: A Technical History of Los Alamos During the Oppenheimer Years, 1943–1945. New York: Cambridge University Press. ISBN 0-521-44132-3. OCLC 26764320.

newyorker.com (Global: 191^st place; English: 122^nd place)

Samuels 2008. Samuels, David (15 December 2008). "Atomic John: A truck driver uncovers secrets about the first nuclear bombs". The New Yorker. Retrieved 30 August 2013.

nih.gov (Global: 5^th place; English: 5^th place)

pubmed.ncbi.nlm.nih.gov

Richardson RR 2009. Richardson, David; et al. (September 2009). "Ionizing Radiation and Leukemia Mortality among Japanese Atomic Bomb Survivors, 1950–2000". Radiation Research. 172 (3): 368–382. Bibcode:2009RadR..172..368R. doi:10.1667/RR1801.1. PMID 19708786. S2CID 12463437.
Izumi BJC 2003. Izumi, S.; Koyama, K.; Soda, M.; Suyama, A. (November 2003). "Cancer incidence in children and young adults did not increase relative to parental exposure to atomic bombs". British Journal of Cancer. 89 (9): 1709–1713. doi:10.1038/sj.bjc.6601322. PMC 2394417. PMID 14583774.
Izumi IJC 2003. Izumi, S.; Suyama, A.; Koyama, K. (November 2003). "Radiation-related mortality among offspring of atomic bomb survivors: a half-century of follow-up". International Journal of Cancer. 107 (2): 292–297. doi:10.1002/ijc.11400. PMID 12949810. S2CID 23902907.
Putnam, F. W. (12 May 1998). "The Atomic Bomb Casualty Commission in retrospect". Proceedings of the National Academy of Sciences of the United States of America. 95 (10): 5426–5431. Bibcode:1998PNAS...95.5426P. doi:10.1073/pnas.95.10.5426. PMC 33857. PMID 9576898.

ncbi.nlm.nih.gov

Izumi BJC 2003. Izumi, S.; Koyama, K.; Soda, M.; Suyama, A. (November 2003). "Cancer incidence in children and young adults did not increase relative to parental exposure to atomic bombs". British Journal of Cancer. 89 (9): 1709–1713. doi:10.1038/sj.bjc.6601322. PMC 2394417. PMID 14583774.
Putnam, F. W. (12 May 1998). "The Atomic Bomb Casualty Commission in retrospect". Proceedings of the National Academy of Sciences of the United States of America. 95 (10): 5426–5431. Bibcode:1998PNAS...95.5426P. doi:10.1073/pnas.95.10.5426. PMC 33857. PMID 9576898.

nuclearsecrecy.com (Global: low place; English: low place)

Wellerstein, Alex. "NUKEMAP". nuclearsecrecy.com. Alex Wellerstein. Retrieved 28 July 2021.

nuclearweaponarchive.org (Global: 4,373^rd place; English: 3,351^st place)

Sublette, Carey. "Nuclear Weapons Frequently Asked Questions, Section 8.0: The First Nuclear Weapons". Retrieved 29 August 2013.

radionetherlandsarchives.org (Global: low place; English: low place)

"The ongoing research into the effects of radiation". Radio Netherlands Archives. 31 July 2005. Retrieved 16 December 2018.

rerf.or.jp (Global: low place; English: low place)

Genetic Effects. "Genetic Effects: Question #7". Radiation Effects Research Foundation. Retrieved 6 November 2013.

semanticscholar.org (Global: 15^th place; English: 8^th place)

api.semanticscholar.org

Richardson RR 2009. Richardson, David; et al. (September 2009). "Ionizing Radiation and Leukemia Mortality among Japanese Atomic Bomb Survivors, 1950–2000". Radiation Research. 172 (3): 368–382. Bibcode:2009RadR..172..368R. doi:10.1667/RR1801.1. PMID 19708786. S2CID 12463437.
Izumi IJC 2003. Izumi, S.; Suyama, A.; Koyama, K. (November 2003). "Radiation-related mortality among offspring of atomic bomb survivors: a half-century of follow-up". International Journal of Cancer. 107 (2): 292–297. doi:10.1002/ijc.11400. PMID 12949810. S2CID 23902907.

thebulletin.org (Global: 6,637^th place; English: 5,064^th place)

Wellerstein, Alex (4 August 2020). "Counting the Dead at Hiroshima and Nagasaki". Bulletin of the Atomic Scientists.

vt.edu (Global: 2,818^th place; English: 1,692^nd place)

cddc.vt.edu

The Atomic Bombings of Hiroshima and Nagasaki, 1946, p. 14. The Atomic Bombings of Hiroshima and Nagasaki (PDF) (Report). The Manhattan Engineer District. 29 June 1946. Archived from the original (PDF) on 6 April 2012. Retrieved 6 November 2013. This report can also be found here and here.
The Atomic Bombings of Hiroshima and Nagasaki, 1946, pp. 21–23. The Atomic Bombings of Hiroshima and Nagasaki (PDF) (Report). The Manhattan Engineer District. 29 June 1946. Archived from the original (PDF) on 6 April 2012. Retrieved 6 November 2013. This report can also be found here and here.
The Atomic Bombings of Hiroshima and Nagasaki, 1946, p. 21. The Atomic Bombings of Hiroshima and Nagasaki (PDF) (Report). The Manhattan Engineer District. 29 June 1946. Archived from the original (PDF) on 6 April 2012. Retrieved 6 November 2013. This report can also be found here and here.

web.archive.org (Global: 1^st place; English: 1^st place)

The Atomic Bombings of Hiroshima and Nagasaki, 1946, p. 14. The Atomic Bombings of Hiroshima and Nagasaki (PDF) (Report). The Manhattan Engineer District. 29 June 1946. Archived from the original (PDF) on 6 April 2012. Retrieved 6 November 2013. This report can also be found here and here.
Nuclear Weapon Thermal Effects 1998. "Nuclear Weapon Thermal Effects". Special Weapons Primer, Weapons of Mass Destruction. Federation of American Scientists. 1998. Archived from the original on 22 April 2013. Retrieved 5 November 2013.
Human Shadow Etched in Stone. "Human Shadow Etched in Stone". Photographic Display. Hiroshima Peace Memorial Museum. Archived from the original on 20 July 2021. Retrieved 6 November 2013.
The Atomic Bombings of Hiroshima and Nagasaki, 1946, pp. 21–23. The Atomic Bombings of Hiroshima and Nagasaki (PDF) (Report). The Manhattan Engineer District. 29 June 1946. Archived from the original (PDF) on 6 April 2012. Retrieved 6 November 2013. This report can also be found here and here.
The Atomic Bombings of Hiroshima and Nagasaki, 1946, p. 21. The Atomic Bombings of Hiroshima and Nagasaki (PDF) (Report). The Manhattan Engineer District. 29 June 1946. Archived from the original (PDF) on 6 April 2012. Retrieved 6 November 2013. This report can also be found here and here.

worldcat.org (Global: 4^th place; English: 4^th place)

search.worldcat.org

Serber & Crease 1998, p. 104. Serber, Robert; Crease, Robert P. (1998). Peace & War: Reminiscences of a Life on the Frontiers of Science. New York: Columbia University Press. ISBN 978-0231105460. OCLC 37631186.
Rhodes 1986, p. 541. Rhodes, Richard (1986). The Making of the Atomic Bomb. New York: Simon & Schuster. ISBN 0-684-81378-5. OCLC 13793436.
The "Mark" nomenclature did not become standardized until the postwar period. Some wartime documents refer to "Mark I" and "Mark II" as different gun-type weapons, or "Mark II" and "Mark III" as referring to non-lens implosion concepts that were pursued until the spring of 1945 (with "Mark IV" being the lensed Fat Man design). Eventually the "Mark I" was used exclusively for Little Boy, and "Mark III" for Fat Man. See e.g., Hewlett & Anderson 1962, pp. 251–252, Hansen 1995a, p. 65, and discussion of nonlens program in Hoddeson et al. 1993, pp. 300, 312. Hewlett, Richard G.; Anderson, Oscar E. (1962). The New World, 1939–1946 (PDF). Vol. I: A History of the United States Atomic Energy Commission. University Park, Penn.: Pennsylvania State University Press. LCCN 62-14633. OCLC 637004643. Retrieved 26 March 2013. Reprint (1990): ISBN 0-520-07186-7. Hansen, Chuck (1995a). Volume VII: The Development of US Nuclear Weapons. Swords of Armageddon: US Nuclear Weapons Development since 1945. Sunnyvale, California: Chuckelea Publications. ISBN 978-0-9791915-7-2. OCLC 231585284. Hoddeson, Lillian; Henriksen, Paul W.; Meade, Roger A.; Westfall, Catherine L. (1993). Critical Assembly: A Technical History of Los Alamos During the Oppenheimer Years, 1943–1945. New York: Cambridge University Press. ISBN 0-521-44132-3. OCLC 26764320.
Hoddeson et al. 1993, p. 419. Hoddeson, Lillian; Henriksen, Paul W.; Meade, Roger A.; Westfall, Catherine L. (1993). Critical Assembly: A Technical History of Los Alamos During the Oppenheimer Years, 1943–1945. New York: Cambridge University Press. ISBN 0-521-44132-3. OCLC 26764320.
Ramsey, N. F. (2012). "History of Project A". In Coster-Mullen, John (ed.). Atom Bombs: The Top Secret Inside Story of Little Boy and Fat Man. United States: J. Coster-Mullen. OCLC 298514167.
Groves 1962, p. 260. Groves, Leslie (1962). Now It Can Be Told: The Story of the Manhattan Project. New York: Harper. OCLC 537684.
Hoddeson et al. 1993, pp. 42–44. Hoddeson, Lillian; Henriksen, Paul W.; Meade, Roger A.; Westfall, Catherine L. (1993). Critical Assembly: A Technical History of Los Alamos During the Oppenheimer Years, 1943–1945. New York: Cambridge University Press. ISBN 0-521-44132-3. OCLC 26764320.
Hoddeson et al. 1993, pp. 67, 75. Hoddeson, Lillian; Henriksen, Paul W.; Meade, Roger A.; Westfall, Catherine L. (1993). Critical Assembly: A Technical History of Los Alamos During the Oppenheimer Years, 1943–1945. New York: Cambridge University Press. ISBN 0-521-44132-3. OCLC 26764320.
Groves 1962, pp. 162–163. Groves, Leslie (1962). Now It Can Be Told: The Story of the Manhattan Project. New York: Harper. OCLC 537684.
Hoddeson et al. 1993, pp. 82–84. Hoddeson, Lillian; Henriksen, Paul W.; Meade, Roger A.; Westfall, Catherine L. (1993). Critical Assembly: A Technical History of Los Alamos During the Oppenheimer Years, 1943–1945. New York: Cambridge University Press. ISBN 0-521-44132-3. OCLC 26764320.
Hoddeson et al. 1993, pp. 87, 114. Hoddeson, Lillian; Henriksen, Paul W.; Meade, Roger A.; Westfall, Catherine L. (1993). Critical Assembly: A Technical History of Los Alamos During the Oppenheimer Years, 1943–1945. New York: Cambridge University Press. ISBN 0-521-44132-3. OCLC 26764320.
Hoddeson et al. 1993, p. 228. Hoddeson, Lillian; Henriksen, Paul W.; Meade, Roger A.; Westfall, Catherine L. (1993). Critical Assembly: A Technical History of Los Alamos During the Oppenheimer Years, 1943–1945. New York: Cambridge University Press. ISBN 0-521-44132-3. OCLC 26764320.
Hoddeson et al. 1993, pp. 245–249. Hoddeson, Lillian; Henriksen, Paul W.; Meade, Roger A.; Westfall, Catherine L. (1993). Critical Assembly: A Technical History of Los Alamos During the Oppenheimer Years, 1943–1945. New York: Cambridge University Press. ISBN 0-521-44132-3. OCLC 26764320.
Hoddeson et al. 1993, p. 257. Hoddeson, Lillian; Henriksen, Paul W.; Meade, Roger A.; Westfall, Catherine L. (1993). Critical Assembly: A Technical History of Los Alamos During the Oppenheimer Years, 1943–1945. New York: Cambridge University Press. ISBN 0-521-44132-3. OCLC 26764320.
Hoddeson et al. 1993, p. 262. Hoddeson, Lillian; Henriksen, Paul W.; Meade, Roger A.; Westfall, Catherine L. (1993). Critical Assembly: A Technical History of Los Alamos During the Oppenheimer Years, 1943–1945. New York: Cambridge University Press. ISBN 0-521-44132-3. OCLC 26764320.
Nichols 1987, pp. 166, 175–176. Nichols, Kenneth (1987). The Road to Trinity: A Personal Account of How America's Nuclear Policies Were Made. New York: William Morrow. ISBN 068806910X. OCLC 15223648.
Hoddeson et al. 1993, p. 265. Hoddeson, Lillian; Henriksen, Paul W.; Meade, Roger A.; Westfall, Catherine L. (1993). Critical Assembly: A Technical History of Los Alamos During the Oppenheimer Years, 1943–1945. New York: Cambridge University Press. ISBN 0-521-44132-3. OCLC 26764320.
Coster-Mullen 2012, p. 30. Coster-Mullen, John (2012). Atom Bombs: The Top Secret Inside Story of Little Boy and Fat Man. Waukesha, Wisconsin: J. Coster-Mullen. OCLC 298514167.
Hansen 1995, pp. 111–112. Hansen, Chuck (1995). Volume V: US Nuclear Weapons Histories. Swords of Armageddon: US Nuclear Weapons Development since 1945. Sunnyvale, California: Chuckelea Publications. ISBN 978-0-9791915-0-3. OCLC 231585284.
Hoddeson et al. 1993, p. 293. Hoddeson, Lillian; Henriksen, Paul W.; Meade, Roger A.; Westfall, Catherine L. (1993). Critical Assembly: A Technical History of Los Alamos During the Oppenheimer Years, 1943–1945. New York: Cambridge University Press. ISBN 0-521-44132-3. OCLC 26764320.
Hansen 1995, p. 113. Hansen, Chuck (1995). Volume V: US Nuclear Weapons Histories. Swords of Armageddon: US Nuclear Weapons Development since 1945. Sunnyvale, California: Chuckelea Publications. ISBN 978-0-9791915-0-3. OCLC 231585284.
Hoddeson et al. 1993, p. 333. Hoddeson, Lillian; Henriksen, Paul W.; Meade, Roger A.; Westfall, Catherine L. (1993). Critical Assembly: A Technical History of Los Alamos During the Oppenheimer Years, 1943–1945. New York: Cambridge University Press. ISBN 0-521-44132-3. OCLC 26764320.
Coster-Mullen 2012, p. 18. Coster-Mullen, John (2012). Atom Bombs: The Top Secret Inside Story of Little Boy and Fat Man. Waukesha, Wisconsin: J. Coster-Mullen. OCLC 298514167.
Coster-Mullen 2012, p. 27. Coster-Mullen, John (2012). Atom Bombs: The Top Secret Inside Story of Little Boy and Fat Man. Waukesha, Wisconsin: J. Coster-Mullen. OCLC 298514167.
Coster-Mullen 2012, pp. 18–19, 27. Coster-Mullen, John (2012). Atom Bombs: The Top Secret Inside Story of Little Boy and Fat Man. Waukesha, Wisconsin: J. Coster-Mullen. OCLC 298514167.
Hoddeson et al. 1993, pp. 263–265. Hoddeson, Lillian; Henriksen, Paul W.; Meade, Roger A.; Westfall, Catherine L. (1993). Critical Assembly: A Technical History of Los Alamos During the Oppenheimer Years, 1943–1945. New York: Cambridge University Press. ISBN 0-521-44132-3. OCLC 26764320.
Coster-Mullen 2012, p. 28. Coster-Mullen, John (2012). Atom Bombs: The Top Secret Inside Story of Little Boy and Fat Man. Waukesha, Wisconsin: J. Coster-Mullen. OCLC 298514167.
Coster-Mullen 2012, pp. 23–24. Coster-Mullen, John (2012). Atom Bombs: The Top Secret Inside Story of Little Boy and Fat Man. Waukesha, Wisconsin: J. Coster-Mullen. OCLC 298514167.
Hansen 1995a, pp. 2–5. Hansen, Chuck (1995a). Volume VII: The Development of US Nuclear Weapons. Swords of Armageddon: US Nuclear Weapons Development since 1945. Sunnyvale, California: Chuckelea Publications. ISBN 978-0-9791915-7-2. OCLC 231585284.
Campbell 2005, pp. 46, 80. Campbell, Richard H. (2005). The Silverplate Bombers: A History and Registry of the Enola Gay and Other B-29s Configured to Carry Atomic Bombs. Jefferson, North Carolina: McFarland & Company. ISBN 0-7864-2139-8. OCLC 58554961.
Coster-Mullen 2012, pp. 100–101. Coster-Mullen, John (2012). Atom Bombs: The Top Secret Inside Story of Little Boy and Fat Man. Waukesha, Wisconsin: J. Coster-Mullen. OCLC 298514167.
Coster-Mullen 2012, pp. 34–35. Coster-Mullen, John (2012). Atom Bombs: The Top Secret Inside Story of Little Boy and Fat Man. Waukesha, Wisconsin: J. Coster-Mullen. OCLC 298514167.
Craven & Cate 1983, pp. 722–723. Craven, W. F.; Cate, J. L., eds. (1983). The Pacific: Matterhorn to Nagasaki, June 1944 to August 1945. The Army Air Forces in World War II. Vol. 5. Washington, D.C.: Office of Air Force History. OCLC 9828710. Retrieved 28 March 2023.
Groves 1962, p. 269. Groves, Leslie (1962). Now It Can Be Told: The Story of the Manhattan Project. New York: Harper. OCLC 537684.
Hoddeson et al. 1993, p. 393. Hoddeson, Lillian; Henriksen, Paul W.; Meade, Roger A.; Westfall, Catherine L. (1993). Critical Assembly: A Technical History of Los Alamos During the Oppenheimer Years, 1943–1945. New York: Cambridge University Press. ISBN 0-521-44132-3. OCLC 26764320.
Coster-Mullen 2012, pp. 86–87. Coster-Mullen, John (2012). Atom Bombs: The Top Secret Inside Story of Little Boy and Fat Man. Waukesha, Wisconsin: J. Coster-Mullen. OCLC 298514167.
Coster-Mullen 2012, p. 85. Coster-Mullen, John (2012). Atom Bombs: The Top Secret Inside Story of Little Boy and Fat Man. Waukesha, Wisconsin: J. Coster-Mullen. OCLC 298514167.
Abrahamson & Carew 2002, pp. 41–42. Abrahamson, James L.; Carew, Paul H. (2002). Vanguard of American Atomic Deterrence. Westport, Connecticut: Praeger. ISBN 0-275-97819-2. OCLC 49859889.
Hansen 1995, pp. 116–118. Hansen, Chuck (1995). Volume V: US Nuclear Weapons Histories. Swords of Armageddon: US Nuclear Weapons Development since 1945. Sunnyvale, California: Chuckelea Publications. ISBN 978-0-9791915-0-3. OCLC 231585284.
Hansen 1995, p. 115. Hansen, Chuck (1995). Volume V: US Nuclear Weapons Histories. Swords of Armageddon: US Nuclear Weapons Development since 1945. Sunnyvale, California: Chuckelea Publications. ISBN 978-0-9791915-0-3. OCLC 231585284.

yale.edu (Global: 559^th place; English: 389^th place)

avalon.law.yale.edu

The Atomic Bombings of Hiroshima and Nagasaki, 1946, p. 14. The Atomic Bombings of Hiroshima and Nagasaki (PDF) (Report). The Manhattan Engineer District. 29 June 1946. Archived from the original (PDF) on 6 April 2012. Retrieved 6 November 2013. This report can also be found here and here.
The Atomic Bombings of Hiroshima and Nagasaki, 1946, pp. 21–23. The Atomic Bombings of Hiroshima and Nagasaki (PDF) (Report). The Manhattan Engineer District. 29 June 1946. Archived from the original (PDF) on 6 April 2012. Retrieved 6 November 2013. This report can also be found here and here.
The Atomic Bombings of Hiroshima and Nagasaki, 1946, p. 21. The Atomic Bombings of Hiroshima and Nagasaki (PDF) (Report). The Manhattan Engineer District. 29 June 1946. Archived from the original (PDF) on 6 April 2012. Retrieved 6 November 2013. This report can also be found here and here.

Little Boy (English Wikipedia)

adsabs.harvard.edu (Global: 14th place; English: 9th place)

ui.adsabs.harvard.edu

anesi.com (Global: low place; English: low place)

archive.org (Global: 6th place; English: 6th place)

atomicarchive.com (Global: low place; English: low place)

books.google.com (Global: 3rd place; English: 3rd place)

city.hiroshima.jp (Global: low place; English: low place)

pcf.city.hiroshima.jp

csu.edu.au (Global: low place; English: low place)

marshall.csu.edu.au

doi.org (Global: 2nd place; English: 2nd place)

fas.org (Global: 730th place; English: 519th place)

fourmilab.ch (Global: low place; English: low place)

governmentattic.org (Global: low place; English: 6,646th place)

gutenberg.org (Global: 629th place; English: 427th place)

ibiblio.org (Global: 1,093rd place; English: 690th place)

lanl.gov (Global: 5,474th place; English: 5,230th place)

library.lanl.gov

loc.gov (Global: 63rd place; English: 47th place)

lccn.loc.gov

newyorker.com (Global: 191st place; English: 122nd place)

nih.gov (Global: 5th place; English: 5th place)

pubmed.ncbi.nlm.nih.gov

ncbi.nlm.nih.gov

nuclearsecrecy.com (Global: low place; English: low place)

nuclearweaponarchive.org (Global: 4,373rd place; English: 3,351st place)

radionetherlandsarchives.org (Global: low place; English: low place)

rerf.or.jp (Global: low place; English: low place)

semanticscholar.org (Global: 15th place; English: 8th place)

api.semanticscholar.org

thebulletin.org (Global: 6,637th place; English: 5,064th place)

vt.edu (Global: 2,818th place; English: 1,692nd place)

cddc.vt.edu

web.archive.org (Global: 1st place; English: 1st place)

worldcat.org (Global: 4th place; English: 4th place)

search.worldcat.org

yale.edu (Global: 559th place; English: 389th place)

avalon.law.yale.edu

adsabs.harvard.edu (Global: 14^th place; English: 9^th place)

archive.org (Global: 6^th place; English: 6^th place)

books.google.com (Global: 3^rd place; English: 3^rd place)

doi.org (Global: 2^nd place; English: 2^nd place)

fas.org (Global: 730^th place; English: 519^th place)

governmentattic.org (Global: low place; English: 6,646^th place)

gutenberg.org (Global: 629^th place; English: 427^th place)

ibiblio.org (Global: 1,093^rd place; English: 690^th place)

lanl.gov (Global: 5,474^th place; English: 5,230^th place)

loc.gov (Global: 63^rd place; English: 47^th place)

newyorker.com (Global: 191^st place; English: 122^nd place)

nih.gov (Global: 5^th place; English: 5^th place)

nuclearweaponarchive.org (Global: 4,373^rd place; English: 3,351^st place)

semanticscholar.org (Global: 15^th place; English: 8^th place)

thebulletin.org (Global: 6,637^th place; English: 5,064^th place)

vt.edu (Global: 2,818^th place; English: 1,692^nd place)

web.archive.org (Global: 1^st place; English: 1^st place)

worldcat.org (Global: 4^th place; English: 4^th place)

yale.edu (Global: 559^th place; English: 389^th place)