Jornada del Muerto desert, New Mexico, U.S.
Photographer: Unknown.

Clad in a pair of old army boots, shorts and with his shirt unbuttoned for better ventilation against the intense desert heat. Canadian physicist Dr. Louis Slotin leans against a partially assembled Trinity Gadget in this photo taken on the 13th of July 1945. Two days before the device’s scheduled detonation in a remote location of Jornada del Muerto in New Mexico was to usher in the world’s first atomic explosion, at 5:29 a.m.

A scrawny 34-year-old assistant researcher with a PhD in Physical Chemistry, who built the world’s first Cyclotron during his five-year tenure at the University of Chicago, prior to arriving at Los Alamos in December 1945. Slotin was an indispensable member of the nuclear project’s Critically Assembly Group. Tasked among other things with the assembly of the most dangerous components of an atomic bomb.

Which on this day he had performed with drilled precision. First by monitoring for radiation spikes as a crew had taken to assembling the Gadget inside a generator lit ranch house with tapered walls and aluminium painted roofs. Then by placing the core component within the Gadget itself.

Slotin, the chief armourer.

While Slotin played an important role in the development of the atomic project and is known to have earned the nickname of chief armourer for his expertise in handling volatile materials with ease. His methods nonetheless are considered by many in retrospect to be somewhat reckless and bold. Especially in the light of Physics Laureate Enrico Fermi, once cautioning him to be more careful in his early days of joining Los Alamos.

More widely known for the accident that befell him on the 21st of May 1946 rather than his constructive role in the Manhattan Project. Slotin at the time of his mishap was experimenting with the same 6.19 grams of nickel-plated plutonium orb that earlier had resulted in the death of his friend and assistant Harry K. Daghlian on the 15th September 1945(see Farbound.Net snippet: The lethal after-effects of radiation poisoning).

Risky techniques.

Authors and historians have generally considered his mishap to be the result of his own risky techniques. Emerging from the confidence of having repeatedly done a procedure countless times. And one of those instances when even experienced scientists have displayed the tendency to hurry through a mundane load. Forsaking safety in the bargain.

How Slotin’s accident had happened.

Betiding some nine months after the death of Daghlian. Slotin’s accident had occurred during an unscheduled experiment he had organized to familiarize his successor, Allen Cushman Graves, with the process of monitoring neutron emission with a critical assembly unit. He had conducted this experiment in the presence of six other scientists.

Slotin’s accident had taken place when he had abandoned the safety protocol of using wooden blocks to keep separate a Beryllium shell from a Plutonium core, and instead relied on the thin blade of a screwdriver.

Either because of a miscalculation or slip, the spheres had connected and created a super-critical mass. Which in turn had produced a sudden burst of neutrons, gamma rays, soft x-rays and electrons. Exposing him to a total of 2100 rem of radiation. He had been further exposed when he had dismantled the assembly by hand to prevent an explosion.

Symptoms of radiation exposure.

Nauseated within moments and exhibiting more or less the same symptoms as Daghlian. Slotin had expired nine days later at the Los Alamos hospital on the 30th of May 1946. His exposure of 2100 rem had been far and above the 510 rem Daghlian had been exposed to in August 1945.

Medical records indicate that during the medical treatment, Slotin’s skin had turned blue then red. His white blood cells were completely obliterated, and his end had come about in a coma – with his parents by his bedside.

Studies conducted later revealed that out of the seven other members who were present with Slotin on that day, the radiation burst was the cause of both minor and serious ailments. While Allen Graves, who was later a divisional head at Los Almos, was afflicted with cataracts. Four other scientists developed either acute myelogenous leukaemia, refractory anaemia or myocardial infarction. Which led to their deaths at a later date.

Known to his colleagues at Los Alamos as a quiet and friendly person. Someone easy to get along with. Slotin’s death, however, did not go down in history as a mere accident.

The introduction of robotic arms.

The second death to occur at Los Alamos. His had a moulding effect on the scientific community. Following the accident, all experiments at Los Alamos was brought to a temporary halt in 1946.

Existing laboratories were reinforced with radiation shielding and human operators were substituted with robotic arms. Eventually, a new laboratory at Pajarito Canyon was built.

Inside this laboratory, human operators sheltered inside a safe and secure control room a quarter of a mile away performed experiments with remote control devices.

At the time of his accident, Slotin was on his way out of Los Alamos. Having spent more than a year with the Manhattan project. He had expressed his wish to return back to University of Chicago and was eager to finish his last assignment before departure. Which was to monitor the detonation of an assembly he and Daghlian had created for an atomic test in the coral atoll of Bikini in the Pacific.

His travel permit had come through and he had been impatient to be on his way. Perhaps for the reason that his request to accompany the atomic weapons to Tinian island had been denied. The critical assembly he had performed on the 21st of May 1945 had been the same designated for detonation at Bikini. It was codenamed Operation Crossroad.

The photo.

While most of Daghlian and Slotin’s photos during their hospitalization at Los Alamos hospital was created by army photographer John Michnovicz. Assigned to document activities at the atomic city between October 1944 and 1947. The photo on top does not bear a photographer’s name in the credits.

Yet may perhaps be of Julian E. Mack. A professor of physics at the University of Wisconsin and head of Group G-11 – a special photographic unit assigned to document the weapons physics division during the Trinity test.

The photo is archived by the Los Alamos National Laboratory, the rightful legatee of the former Manhattan Project.