Editing Trinity (nuclear test) (section)

===Personnel===
[[File:Louis Slotin and the Gadget Bomb.jpg|thumb|right|[[Louis Slotin]] and Herbert Lehr prior to insertion of the bomb's tamper plug (visible in front of Lehr's left knee)<ref name="AHF Herbert Lehr">{{cite web |title=Herbert Lehr |url=https://www.atomicheritage.org/profile/herbert-lehr |publisher=Atomic Heritage Foundation |access-date=September 8, 2020 |archive-date=January 16, 2021 |archive-url=https://web.archive.org/web/20210116134534/https://www.atomicheritage.org/profile/herbert-lehr |url-status=live }}</ref>]]
In the final two weeks before the test, some 250 personnel from Los Alamos were at work at the Trinity Site,{{sfn|Bainbridge|1976|p=15}} and Lieutenant Bush's command had ballooned to 125 men guarding and maintaining the base camp. Another 160 men under Major T.O. Palmer were stationed outside the area with vehicles to evacuate the civilian population in the surrounding region should that prove necessary.{{sfn|Bainbridge|1976|p=25}}{{r|wellerstein20150716}} They had enough vehicles to move 450 people to safety and had food and supplies to last them for two days. Arrangements were made for Alamogordo Army Air Field to provide accommodation.{{sfn|Hacker|1987|p=90}} Groves warned [[Governor of New Mexico]] [[John J. Dempsey]] that [[martial law]] might have to be declared in the southwestern part of the state.{{sfn|Norris|2002|p=402}}{{r|wellerstein20150716}}

Shelters were established {{convert|10000|yd}} due north, west, and south of the tower, each with its own chief: Robert Wilson at N-10,000, John Manley at W-10,000 and [[Frank Oppenheimer]] at S-10,000.{{sfn|Bainbridge|1976|pp=29–30}} Many other observers were around {{convert|20|mi}} away, and some others were scattered at different distances, some in more informal situations. [[Richard Feynman]] claimed to be the only person to see the explosion without the goggles provided, relying on a truck windshield to screen out harmful [[ultraviolet]] wavelengths.{{sfn|Feynman|1985|p=134}} Bainbridge asked Groves to keep his VIP list down to ten. He chose himself, Oppenheimer, [[Richard Tolman]], [[Vannevar Bush]], [[James Bryant Conant|James Conant]], Brigadier General [[Thomas F. Farrell]], [[Charles Lauritsen]], [[Isidor Isaac Rabi]], Sir [[G. I. Taylor|Geoffrey Taylor]], and Sir [[James Chadwick]].{{sfn|Bainbridge|1976|p=25}} The VIPs viewed the test from Compania Hill (also called Compaña Hill or Cerro de la Colorado), about {{convert|20|mi}} northwest of the tower.<ref name="ABQ"/><ref>{{cite web |url=https://brendafleming.com/blog/2022/1/19/photo-essay-trinity-site |title=PHOTO ESSAY: TRINITY SITE |last=Fleming |first=Brenda |date=January 19, 2022 |access-date=2024-07-22}}</ref>
[[File:HD.4G.053 (10540204545).jpg|thumb|left|[[Norris Bradbury]] with the assembled bomb atop the test tower. He later succeeded Oppenheimer as director of Los Alamos.]]

[[Photographic film]] was placed in nearby towns to detect radioactive contamination, and [[seismograph]]s were placed in [[Tucson]], [[Denver]], and [[Chihuahua City|Chihuahua, Mexico]] to determine how far the explosion could be sensed. Calculations stated that even if the mechanical and electrical systems did not fail, the likelihood of a non-optimal test was greater than 10%.{{r|wellerstein20150716}} The observers set up a [[betting pool]] on the results of the test. Teller was the most optimistic, predicting {{convert|45|ktonTNT}}.{{sfn|Rhodes|1986|p=656}} He wore gloves to protect his hands and sunglasses underneath the [[welding goggles]] that the government had supplied everyone with.<ref name="ABQ"/> He was one of the few scientists to watch the test (with eye protection), instead of following orders to lie on the ground with his back turned.<ref>{{cite journal |title=Edward Teller, RIP |url=https://www.thenewatlantis.com/publications/edward-teller-rip |journal=The New Atlantis |issue=3 |pages=105–107 |date=Fall 2003 |access-date=January 7, 2015 |url-status=dead |archive-url=https://web.archive.org/web/20160303233937/http://www.thenewatlantis.com/publications/edward-teller-rip |archive-date=March 3, 2016 }}</ref> He also brought suntan lotion, which he shared with the others.{{sfn|Rhodes|1986|p=668}} Ramsey chose zero (a complete [[dud]]), Robert Oppenheimer chose {{convert|0.3|ktonTNT}}, Kistiakowsky {{convert|1.4|ktonTNT}}, and Bethe chose {{convert|8|ktonTNT}}.{{sfn|Rhodes|1986|p=656}} Rabi, the last to arrive, took the only remaining choice{{snd}}{{convert|18|ktonTNT}}, which turned out to be the winner.{{sfn|Rhodes|1986|p=677}} Bethe later stated that his choice of 8 kt was exactly the value calculated by Segrè, and he was swayed by Segrè's authority over that of a more junior [but unnamed] member of Segrè's group who had calculated 20 kt.<ref>{{cite web |url=https://www.webofstories.com/play/hans.bethe/95 |title=The atomic bomb test for 'Fat Man' – Hans Bethe |publisher=Web of stories |access-date=October 19, 2016 |archive-date=April 4, 2020 |archive-url=https://web.archive.org/web/20200404220157/http://www.webofstories.com/play/hans.bethe/95 |url-status=live }}</ref>

[[Enrico Fermi]] offered to take wagers among the top physicists and military present on whether the atmosphere would ignite, and if so whether it would destroy just the state or incinerate the entire planet.{{sfn|Rhodes|1986|p=664}}<ref name="WP-20220722">{{cite news |last=Johnson |first=Mark |title=How Oppenheimer weighed the odds of an atomic bomb test ending Earth |url=https://www.washingtonpost.com/science/2023/07/22/oppenheimer-manhattan-project-history-atomic-bomb-test/ |date=July 22, 2023 |newspaper=[[The Washington Post]] |url-status=live |archive-url=https://archive.today/20230722123414/https://www.washingtonpost.com/science/2023/07/22/oppenheimer-manhattan-project-history-atomic-bomb-test/ |archive-date=July 22, 2023 |access-date=July 22, 2023 }}</ref> This last result had been previously calculated by Bethe to be almost impossible,{{sfn|Hamming|1998|pp=640–650}}<ref name="LA602">{{cite web |url=https://fas.org/sgp/othergov/doe/lanl/docs1/00329010.pdf |title=Report LA-602, Ignition of the Atmosphere With Nuclear Bombs |publisher=[[Los Alamos National Laboratory]] |access-date=December 29, 2013 |archive-date=March 31, 2020 |archive-url=https://web.archive.org/web/20200331041344/https://fas.org/sgp/othergov/doe/lanl/docs1/00329010.pdf |url-status=live }}</ref>{{efn|The reaction Teller was most concerned with was: {{nuclide|nitrogen|14}} + {{nuclide|nitrogen|14}} → {{nuclide|magnesium|24}} + {{nuclide|helium|4}} (alpha particle) + 17.7 MeV.<ref>{{harvnb|Bethe|1991|p=30}}.</ref>}} although for a while it had caused some of the scientists some anxiety. Bainbridge was furious with Fermi for frightening the guards, some of whom asked to be relieved;{{sfn|Lamont|1966|p=197}} his own biggest fear was that nothing at all would happen, in which case he would have to return to the tower to investigate.{{sfn|Bainbridge|1975|p=44}}