A Reported Radiation Dose of 5.1 Sv in the 1945 Harry Daghlian Criticality Accident

The criticality accident involving Harry K. Daghlian Jr. occurred at Los Alamos, New Mexico, on 21 August 1945. During a criticality experiment involving a plutonium assembly and tungsten-carbide reflector blocks, a block accidentally fell into the assembly and an unintended excursion occurred [1-4]. The National Park Service records Daghlian's death on 15 September 1945 [3]. A central issue is the dose value associated with the accident. Oettingen's computational study reports approximately 5.1 Sv [1], whereas UNSCEAR lists an estimated whole-body dose of 5.1 Gy for the experimenter and 0.5 Gy for a guard [2]. Gray measures absorbed dose; sievert is used for equivalent and effective dose in radiation protection [6,7]. This review preserves the difference rather than treating the numbers as interchangeable.