ATOMIC BOMB INDUCED 152Eu: RECONCILIATION OF DISCREPANCY BETWEEN MEASUREMENTS AND CALCULATION

Komura, K.; Hoshi, Masaharu; Endo, Satoru; Imanaka, Tadayuki; Sd, Egbert; Rühm, W.; Fukushima, H.; Fujita, Shoichiro

doi:10.1097/01.hp.0000251246.58759.2f

Cited by 6 publications

(2 citation statements)

References 16 publications

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“…Filled and open lozenges indicate the ratios at side and top surfaces of Aioi bridge legs around 300 m 2) . Filled circles indicate the ratios measured by Komura, et al 3) . Filled and open squares indicate the ratios measured by Shizuma, et al 4,5) .…”

Section: Samplesmentioning

confidence: 97%

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Measurements of 152Eu/Eu ratios in surfaces of rock samples near the hypocenter of the Hiroshima atomic bomb

Kato

Honjyo

2011

Radiat. Safety. Manag.

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The152 Eu/Eu ratios were measured at various surface positions of two granite samples (gravestones) in the vicinities of the hypocenter of the Hiroshima atomic bomb. The sample pieces were dissolved and the europium elements were chemically isolated. The radioisotopes of Actinium series in the rock samples were excluded from the europium samples. The measured 152 Eu/Eu ratio was not constant in each surface, and was low at the surface positions close to neighbor gravestone. The 152 Eu/Eu ratios were high at the positions that were largely open for the scattered neutrons from the soil ground. This suggests that the rock materials between sample and soil ground reduced thermal neutron fluence to the sample.

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Section: Samplesmentioning

confidence: 97%

“…Because of the long life (13.537 y) 1) , the 152 Eu activities are still measurable. Many investigations have been performed for measuring the 152 Eu/Eu ratios in the rock samples exposed to the Hiroshima atomic bomb [2][3][4][5][6][7][8] . The data on the .…”

Section: Introductionmentioning

confidence: 99%

Measurements of 152Eu/Eu ratios in surfaces of rock samples near the hypocenter of the Hiroshima atomic bomb

Kato

Honjyo

2011

Radiat. Safety. Manag.

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Gamma-ray exposure from neutron-induced radionuclides in soil in Hiroshima and Nagasaki based on DS02 calculations

Imanaka

Endo

Tanaka

et al. 2008

Radiat Environ Biophys

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As a result of joint efforts by Japanese, US and German scientists, the Dosimetry System 2002 (DS02) was developed as a new dosimetry system, to evaluate individual radiation dose to atomic bomb survivors in Hiroshima and Nagasaki. Although the atomic bomb radiation consisted of initial radiation and residual radiation, only initial radiation was reevaluated in DS02 because, for most survivors in the life span study group, the residual dose was negligible compared to the initial dose. It was reported, however, that there were individuals who entered the city at the early stage after the explosion and experienced hemorrhage, diarrhea, etc., which were symptoms of acute radiation syndrome. In this study, external exposure due to radionuclides induced in soil by atomic bomb neutrons was reevaluated based on DS02 calculations, as a function of both the distance from the hypocenters and the elapsed time after the explosions. As a result, exposure rates of 6 and 4 Gy h(-1) were estimated at the hypocenter at 1 min after the explosion in Hiroshima and Nagasaki, respectively. These exposure rates decreased rapidly by a factor of 1,000 1 day later, and by a factor of 1 million 1 week later. Maximum cumulative exposure from the time of explosion was 1.2 and 0.6 Gy at the hypocenters in Hiroshima and Nagasaki, respectively. Induced radiation decreased also with distance from the hypocenters, by a factor of about 10 at 500 m and a factor of three to four hundreds at 1,000 m. Consequently, a significant exposure due to induced radiation is considered feasible to those who entered the area closer to a distance of 1,000 m from the hypocenters, within one week after the bombing.

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Intercomparison study on 152Eu gamma ray and 36Cl AMS measurements for development of the new Hiroshima–Nagasaki Atomic Bomb Dosimetry System 2002 (DS02)

Hoshi

Endo

Tanaka

et al. 2008

Radiat Environ Biophys

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In the process of developing a new dosimetry system for atomic bomb survivors in Hiroshima and Nagasaki (DS02), an intercomparison study between (152)Eu and (36)Cl measurements was proposed, to reconcile the discrepancy previously observed in the Hiroshima data between measurements and calculations of thermal neutron activation products. Nine granite samples, exposed to the atomic-bomb radiation in Hiroshima within 1,200 m of the hypocenter, as well as mixed standard solutions containing known amounts of europium and chlorine that were neutron-activated by a (252)Cf source, were used for the intercomparison. Gamma-ray spectrometry for (152)Eu was carried out with ultra low-background Ge detectors at the Ogoya Underground Laboratory, Kanazawa University, while three laboratories participated in the (36)Cl measurement using accelerator mass spectrometry (AMS): The Technical University of Munich, Germany, the Lawrence Livermore National Laboratory, USA and the University of Tsukuba, Japan. Measured values for the mixed standard solutions showed good agreement among the participant laboratories. They also agreed well with activation calculations, using the neutron fluences monitored during the (252)Cf irradiation, and the corresponding activation cross-sections taken from the JENDL-3.3 library. The measured-to-calculated ratios obtained were 1.02 for (152)Eu and 0.91-1.02 for (36)Cl, respectively. Similarly, the results of the granite intercomparison indicated good agreement with the DS02 calculation for these samples. An average measured-to-calculated ratio of 0.98 was obtained for all granite intercomparison measurements. The so-called neutron discrepancy that was previously observed and that which included increasing measured-to-calculated ratios for thermal neutron activation products for increasing distances beyond 1,000 m from the hypocenter was not seen in the results of the intercomparison study. The previously claimed discrepancy could be explained by insufficient understanding of the measured data.

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ATOMIC BOMB INDUCED 152Eu: RECONCILIATION OF DISCREPANCY BETWEEN MEASUREMENTS AND CALCULATION

Cited by 6 publications

References 16 publications

Measurements of 152Eu/Eu ratios in surfaces of rock samples near the hypocenter of the Hiroshima atomic bomb

Measurements of 152Eu/Eu ratios in surfaces of rock samples near the hypocenter of the Hiroshima atomic bomb

Gamma-ray exposure from neutron-induced radionuclides in soil in Hiroshima and Nagasaki based on DS02 calculations

Intercomparison study on 152Eu gamma ray and 36Cl AMS measurements for development of the new Hiroshima–Nagasaki Atomic Bomb Dosimetry System 2002 (DS02)

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