著者
甲斐 倫明
出版者
日本保健物理学会
雑誌
保健物理 (ISSN:03676110)
巻号頁・発行日
vol.45, no.1, pp.90-92, 2010 (Released:2011-02-04)
参考文献数
3
著者
長岡 鋭 坂本 隆一 斎藤 公明 堤 正博 森内 茂
出版者
日本保健物理学会
雑誌
保健物理 (ISSN:03676110)
巻号頁・発行日
vol.23, no.4, pp.309-315, 1988 (Released:2010-02-25)
参考文献数
15
被引用文献数
3 6

In order to clarify the diminution characteristics of terrestrial gamma ray exposure rate due to snow cover, measurements were performed on the ground with and without snow cover. The diminution factors observed were 0.36-0.17 for 12-23g/cm2 of water equivalent of the snow cover. According to a calculation by the Monte Carlo method, the corresponding diminution factors were 0.32-0.16. They agreed well as a whole, while the fluctuation of the diminution factors based on the measured exposure rate were fairly large. The fluctuation is deemed to be due to the inhomogeneity in the distribution of the snow cover as well as the gamma ray field. The fluctuation is expected to decrease with increase in the degree of their homogeneity.
著者
酒井 一夫
出版者
日本保健物理学会
雑誌
保健物理 : hoken buturi (ISSN:03676110)
巻号頁・発行日
vol.42, no.2, pp.133-134, 2007-06
著者
吉澤 道夫
出版者
日本保健物理学会
雑誌
保健物理 : hoken buturi (ISSN:03676110)
巻号頁・発行日
vol.44, no.1, pp.36-45, 2009-03-01
参考文献数
29

The International Commission on Radiation Units and Measurements, ICRU, has recommended ‘operational quantities’, such as ambient, directional and personal dose equivalent, for external radiation monitoring. Many discussions have been made on the operational quantities, including necessity of these quantities. The operational quantities have a long history, and ICRU published many reports on this issue. This paper reviews the evolution of operational quantities in the relevant ICRU reports and the ICRP 2007 recommendations.
著者
山田 裕司 宮本 勝宏 小泉 彰
出版者
Japan Health Physics Society
雑誌
保健物理 (ISSN:03676110)
巻号頁・発行日
vol.21, no.4, pp.237-244, 1986
被引用文献数
3 1

It is very important in a nuclear air cleaning system that HEPA (High Efficiency Particulate Air) filter is for reduction of releasing amounts of airborne radioactive particles. HEPA filter, by definition, has a minimum collection efficiency of 99.97% for 0.3μm particles. However, <i>DF</i> (Decontamination Factor), which is necessary for safety management, can not be directly derived from the efficiency. And the current standard defined for 0.3μm particles has no scientific justification, because it has been found that the most penetrating particle size through HEPA filter is not always 0.3μm.<br>In the present paper, a numerical experiment was made in order to estimate a relationship between <i>DF</i> and the efficiency. And new standard, in which the minimum <i>DF</i> is able to be easily obtained, was proposed. In the multistage filtration system, it was found that lower values of <i>DF</i> was possible to be experimentally indicated in the second and the third stages, even if the collection performance of the each filter is the same.
著者
古田 悦子
出版者
Japan Health Physics Society
雑誌
保健物理 : hoken buturi (ISSN:03676110)
巻号頁・発行日
vol.45, no.3, pp.253-261, 2010-09-01

Recently many Japanese wear jewelry as personal ornaments, particularly bracelets. The jewelry is made of gems, jewels, noble metals and so on. Some kinds of jewelry include much amount of radioactive elements more than that of natural range in ores which are in our living-environment. The radioactive concentrations of 25 kinds of jewels and gems, which were easily purchased on a market or through the Internet, were analyzed by HPGe. The bracelet which was made of ceramics showed the highest radioactive concentration and it was estimated as approx. 800 Bq g<sup>-1</sup> of <sup>232</sup>Th and 140 Bq g<sup>-1</sup> of <sup>238</sup>U by assuming radioactive equilibrium among the nuclides in the decay series. Moreover, there was a high radioactive concentration gem including 60 Bq g<sup>-1</sup> of <sup>232</sup>Th and 300 Bq g<sup>-1</sup> of <sup>238</sup>U. The radioactive materials added in the ceramics should be monazite analyzed by a prompt gamma-ray activation analysis method. Though the ceramics became the object of the NORM management by the concentration, the radioactivity of one bracelet does not exceed 8,000 Bq. So, all these jewelry samples do not have to manage as NORM as consumer products according to the guideline by Japanese government. However, the jewelry's activity by deliberate addition of radioactive materials is deemed to be unjustified exposure, that the ICRP led the consideration. It is considered that the NORM guideline should take in the consideration of ICRP and prohibit the addition of radioactive materials to jewelry.
著者
小藪 健 永山 誠司
雑誌
保健物理 : hoken buturi (ISSN:03676110)
巻号頁・発行日
vol.38, no.4, pp.294-298, 2003-12-01
著者
木名瀬 栄
出版者
日本保健物理学会
雑誌
保健物理 : hoken buturi (ISSN:03676110)
巻号頁・発行日
vol.38, no.1, pp.24-27, 2003-03

2003年2月5日(水),東京大学工学部11号館講堂において,「新しい放射線防護体系の構築へ向けた最近の話題」と題する会合が開催された。会合は,日本保健物理学会創立40周年記念行事として位置づけられた企画で,我が国の国際放射線防護委員会(ICRP)委員によるICRP委員会における最近の検討状況の紹介,日本保健物理学会や新たに発足した「ICRP等対応委員会」が果たすべき役割についての意見交換を目的としたものであった。年度末という多忙な時期にも関わらず約60名もの参加があり,現在ICRPにおいて議論されている新しい防護体系についての話題を中心に様々な意見が出された。会合は,下記5つの話題についての講演と意見交換会「日本保健物理学会の果たすべき役割」が予定されていたが,時間の制約により意見交換会は十分に行えなかった。1.主委員会の検討状況紹介 2.第1専門委員会の検討状況紹介 3.第2専門委員会の検討状況紹介 4.第3専門委員会の検討状況紹介 5.第4専門委員会の検討状況紹介 以下に,各話題について,概要と所感を記す。会合は,ICRP等対応委員会委員長藤元憲三先生の司会で進められ,日本保健物理学会長中村尚司先生の挨拶により開会された。開会挨拶の中で,中村先生は,学会などからの様々な意見をICRP等へ発信できる体制つくりが必要である旨述べられた。