Reassessment of γ Doses from the Atomic Bombs in Hiroshima and Nagasaki

Abstract

Reassessment of gamma doses from the atomic bombs in Hiroshima and Nagasaki has been carried out with thermoluminescent measurements of ceramic materials, such as bricks and decorative tiles, which were collected from buildings that remain as they were at the time of the explosions. The thermoluminescent measurements were performed using thermoluminescent dating techniques generally used in archaeology. Annual background dose rates from natural radionuclides in the ceramic materials and from environmental radiation including cosmic rays were determined with commercially available thermoluminescent detectors. A time-zero point at the original firing of the ceramic materials was estimated from the age of the buildings given in "the register book." Total background dose was evaluated by multiplying the period between the time-zero point and the time of measurement by the annual dose rate. The resultant gamma doses in Hiroshima and Nagasaki are given as a function of distance from ground zero and are compared with the DS86 (Dosimetry System 1986) and the T65D (Tentative 1965 Dose) gamma doses.

An update on the discrepancy between calculated and measured neutron-induced radioactivity levels in Hiroshima

“…Quartz grains were extracted from samples taken in both cities and the thermoluminescence (TL) of these grains was analysed by the high-temperature TL method to obtain gamma-ray kerma values. Ichikawa et al (1966) first made such TL measurements in 1963, followed by Hashizume et al (1967) and Maruyama et al (1988). Measurements were also made by six laboratories; these included the National Institute of Radiological Sciences, Hiroshima and Nara Universities in Japan (RERF 1987), the University of Utah in the United States (RERF 1987), and Oxford and Durham Universities in England (RERF 1987).…”

Health effects of radiation exposure in diagnostic radiology

“…They were replaced by a new extensive and refined set of dose estimates (T65D) [11]. In 1986 a system for assessment of individual organ doses for survivors was published [12]. Until recently, the Dosimetry System 1986 (DS86) was subject to debate, mainly with regard to the neutron dosimetry for the Hiroshima bomb.…”

Evaluation of external dose equivalent with thermoluminescent dosimeters from residents living in radiation-contaminated buildings

“…Since the initiation of the Atomic Bomb Survivors (ABS) study in Japan, there have been many epidemiological studies indicating increased health risks, particularly risks in induced cancer, of acute high-dose exposure (BEIR-III, 1980;BEIR-V, 1990;ICRP, 60, ;ICRU, 47, ). The dose effects are not relevant for chronic low-dose exposure, however controversies have persisted through a number of similar studies (Maruyama et al, 1988;Cardis et al, 1995). Limited information on occupational or living experiences around nuclear power or reprocessing plants reveals further conflicting results (Lubenau and Nussbaumer, 1986;Gilbert, 1991;Cardis et al, 1995).…”

“…from 1-140 mSv/yr (Chang and Chang, 1996). The primary sources of the 6°Co radionuclide contamination were from the recycling of discharged radioactive steel produced in one of the major steel reprocessing factories in Taiwan, and the contaminated steel rods were then used for construction of rebut buildings (Marley, 1993;Chang and Kau, 1993;Lubenau and Yusko, 1995;Cardarelli II et al, 1997). Although these are highly controversial and potentially drastic environmental health problems, comprehensive radiation dose reconstructions from these contaminated buildings and residents can provide the best opportunity for a meaningful epidemiological study and can offer a more profound interpretation of the impact of such a radiation hazard on the population.…”

“…One is that the exposure rates among the contaminated apartments have varied greatly from location to location and room to room depending on the levels of contamination of the steel rods and geometrical indoor layout differences. The other is that most of the residents who have lived in the apartments have moved out precipitously and at different times, making the retrospective dose measurements difficult to assess (Maruyama et al, 1988;Haskell, 1993;Degteva et al, 1994Degteva et al, , 1996Goksu et al, 1996). For these reasons, it appears impractical to perform complete area surveys in each building.…”