Evaluation of Atomic-Bomb neutorons by means of low-background r-spectroscopy

低本底 r 能谱评价原子弹中子

• 批准号: 04455019
• 负责人: HASAI Hiromi
• 金额: $ 4.74万
• 依托单位: Grant-in-Aid for Scientific Research (B)
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (B)
• 财政年份: 1992
• 资助国家: 日本
• 起止时间: 1992 至 1993
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-04455019/
• 关键词: Atomic Bomb; Neutron dose; Europium 152; Cobalt 60; residual activity; Depth profile; low-background; Ge detector

The specific activity ^<152>Eu/Eu was measured for 80 samples collected within 1500 m from the Hiroshima hypocenter. The residual activity ^<60>Co was also measured for irons and rocks exposed to the A-bomb neutrons. The results are as follows.1.The directional distribution of emitted neutrons were investigated through the Eu activation. It was found that the activity yield in the direction of WSW decreased rapidly as the function of the distance compered to other directiond. This indicates that the neutron energy was low in this dirction.2.It was shown that the measured ^<152>Eu and ^<60>Co activities were systematically lower than the calculation near the hypocenter and vice versa at long distances beyond 1000 m. These results are consistent with recent measurement of ^<36>Cl by means of accelerator mass spectroscopy.3.Depth distribution of ^<152>Eu in stones are similar at distance 100 m (Motoyasu bridge)and at 500 m (Shirakami Shrine).These results indicate that systematic errors exist in the DS86 neutrons concerning to the source-term spectrum, neutron transport calculation in air, and/or activation measurement.

测量了从广岛低中心者1500 m内收集的80个样品测量的特定活性 ^<152> EU/EU。还测量了暴露于A-BOMB中子的铁和岩石的残留活性 ^<60> CO。结果如下。1。通过欧盟激活研究了发射中子的方向分布。发现随着距离与另一个方向的距离的功能，WSW方向的活性产量迅速降低。这表明在此义务中中子能量很低。2。证明，测得的 ^<152> EU和 ^<60> CO活性系统地低于在低温方面附近的计算，反之亦然。 These results are consistent with recent measurement of ^<36>Cl by means of accelerator mass spectroscopy.3.Depth distribution of ^<152>Eu in stones are similar at distance 100 m (Motoyasu bridge)and at 500 m (Shirakami Shrine).These results indicate that systematic errors exist in the DS86 neutrons concerning to the source-term spectrum, neutron transport calculation in air, and/or activation 测量。

项目成果

M.Hoshi: "Benchmark test of transport ca of Gold and Nickel activation with implications for neutron kerma at Hiroshima" Health Physics. 63. 532-542 (1992)

M.Hoshi：“金和镍活化传输的基准测试及其对广岛中子比释动能的影响”健康物理学。

M.Hoshi: "Benchmark test of transport calculation of Gold and nickel activation with implication for Neutron Kerma at Hiroshima" Health Physics. 63. 532-542 (1992)

M.Hoshi：“金和镍活化输运计算的基准测试及其对广岛中子比释动能的影响”健康物理学。

K.Shizuma: "Specific activities of ^<60>Co and ^<152>Eu in Samples collected from the Atomic Bomb Dome in Hiroshima" Journal of Radiation Research. 33. 151-162 (1992)

K.Shizuma：“从广岛原子弹圆顶收集的样品中 ^<60>Co 和 ^<152>Eu 的比活度”辐射研究杂志。

K.Shizuma: "Residual ^<152>Eu and ^<60>Co activities induced by neutrons from the Hiroshima atomic bomb" Health Physics. 65. 272-282 (1993)

K.Shizuma：“广岛原子弹中子引起的残余 ^<152>Eu 和 ^<60>Co 活动”健康物理学。

M.Hoshi: "Benchmark test of transport caluclation of gold and nickel activation with implication for newtron Kerma at Hiroshima" Heal Physics. 63. 532-542 (1992)

M.Hoshi：“金和镍活化传输计算的基准测试及其对广岛新粒子动能的影响”治愈物理。