Reevaluation of the dosimetry system 1986 (DS86) according to the US-Japan joint study and the analysis of the radiation effects

广岛和长崎幸存者的原子弹剂量是根据美日联合研究批准的1986年剂量学系统(DS86)估算的。该系统被广岛大学辐射效应研究基金会(RERF)和辐射生物医学研究所(RIRBM)使用，并在他们自己的队列研究中评估了幸存者的器官剂量。在对DS86进行测量后，发现由中子活化数据得到的数据与基于DS86的计算结果存在差异。在Eu-152、Co-60、Cl-36和P-32的所有数据中都发现了类似的差异。最大的差异出现在广岛的数据中。例如，在1500米的地面距离上，数据比DS86大5到10倍。我们的研究就是要找出原因，找出解决的办法。问题包括(1)数据采集过程中的问题，(2)中子输运计算中的问题，(3)爆炸过程和推导出的Neu…计算中的问题更多的TRON源项。我们核实了在近地面范围内获取的数据和在运输计算中没有问题。关于远距离拍摄的数据可能会有一些问题，因为伽马射线测量的水平很低？对于这个问题，我们用随机数进行了模拟计算，发现可能包含污染伽马射线。从最近发生的东海村事故的金活化和监测站数据来看，在2000m的地面范围内，热中子和第一中子的数据与计算都有很好的一致性。所以我认为问题出在广岛原子弹的中子源方面。我以复制广岛型原子弹的模型原子弹为基础进行了多次计算，发现如果假设(1)原子弹底部以大约3 cm的平行间距脱落，(2)中子发射高度上升约90m(发射弹下降90m并形成火球)，(3)提高产额约20%，则数据和计算结果是一致的。美国集团不接受这样的假设。然而，2000年5月，考尔博士在RERF举办的研讨会上同意，如果没有这样的假设，我们就不能调整计算和数据。我们将在今年5月再次举行会议。美国集团承诺，他们将以自己的方式解决问题。我们将在那里讨论这一问题，并希望我们能达成全部协议，并为原子弹幸存者获得新的剂量测量系统。较少

Atomic bomb doses for the survivors in Hiroshima and Nagasaki have been estimated according to the Dosimetry system 1986 (DS86), which was approved by the effort of US-Japan joint study. The system was used in Radiation Effects Research Foundation (RERF) and Research Institute for Radiation Biology and Medicine, Hiroshima University (RIRBM) and evaluated organ doses of the survivors in their own cohort study. After the determination of DS86 we found discrepancy between the data obtained from neutron activation data and calculation based on DS86. The discrepancy was found in all of the Eu-152, Co-60, Cl-36 and P-32 data, similarly. The largest discrepancy was found in the Hiroshima data. For example, data are 5 to 10 times larger than DS86 at the 1500 m ground distance. Our study was to find its reason and to get a solution. The problem include (1) problems in data taking process, (2) in neutron transport calculation and (3) in the calculation of the process of explosion and deduced neu … More tron source term. We verified that there were no problems in the data taken at short ground ranges and in the transport calculation. About the data taken at long range may have some problems, since gamma rays measured were very low level? For that problem we made simulation calculation using random numbers and found there may be contamination gamma rays included. From the gold activation and monitoring post data taken at Tokai-mura accident, which recently happened, it was verified that thermal and first neutron data and calculation had good agreement until 2000m ground range. Therefore I considered that the problem is in the neutron source term at Hiroshima atomic bomb. I made many calculation based on the model atomic bomb, which reproduce the Hiroshima type atomic bomb, and found the data and calculation agrees if I assume (1) bottom of the atomic bomb came off as if it had about 3cm parallel spacing, (2) about 90m elevation of the neutron emission height (after the emission bomb fell down 90m and formed fire ball), (3) increase the yield about 20%. US group did not accept such assumptions. However, Dr.Kaul in May 2000 at the workshop held at RERF, agreed that we couldn't adjust the calculation and data without such assumptions. We will have a meeting again this May 2001. US-group promised that they would bring their way to solve the problem. There we will discuss this problem and hope that we will have our whole agreement and that we will obtain new dosimetry system for the atomic bomb survivors. Less