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Volume 15 (1980)
- Issue 4 Pages 247-
- Issue 3 Pages 157-
- Issue 2 Pages 85-
- Issue 1 Pages 1-
Volume 15, Issue 2
Displaying 1-8 of 8 articles from this issue
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Quantitative Analysis Using a Monte Carlo MethodShigehito SUZUKI, Kimihiko IGARASHI1980 Volume 15 Issue 2 Pages 85-92
Published: 1980
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSThe radioactivity in the blood induced by 17.9MeV and 24.5MeV electron beams from a medical betatron was investigated from the point of view of considering the effect of the radioactivation of patients on the patients themselves. It was evaluated by gamma ray spectrometry using a NaI(Tl) detector. The full-energy peak efficiency for 511keV gamma rays from thick cylindrical blood sources was calculated using a Monte Carlo method. From it and the full-energy peak area of the blood spectrum, the radioactive concentration of the blood was obtained for the irradiation of 30min. The activity reduced to half the value at the end of the irradiation after about 138sec. The estimate of the whole body dose from the blood suggested that the activity in the patients induced by the betatron will cause very little harm to the patients.View full abstractDownload PDF (797K) -
Yoshiaki HATTORI, Kazuho MAEDA1980 Volume 15 Issue 2 Pages 93-100
Published: 1980
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSAs a trial evaluation of applicability of multivariate model in an analysis of health effects of radiation workers, the multiple logistic function method was applied to the data of occupational exposure record and long term absence record obtained from 593 employees of two institutions both of which practice R & D relating nuclear power.
In order to estimate parameters of multiple logistic function by maximum likelihood method, followings were defined as variables: age, length of employment and cumulative exposure dose of radiation as independent variables, and the fact that whether the individual worker had the experience of absence lasting more than a week or not as a dependent variable.
As the results, due to shortage of amount of data, only the age of workers shows a significant relationship with the absence data, the other variables do not have any significant results in the association with absence.
In this preliminary trial, the applicability of multiple logistic function model in risk estimation of long term occupational exposure was not clearly demonstrated because of data shortage. To testify the applicability, further investigations will be needed, accumulating plenty of data concerning exposure and health effects.View full abstractDownload PDF (824K) -
Shigeru KUMAZAWA, Hiroshi MATSUI1980 Volume 15 Issue 2 Pages 101-109
Published: 1980
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSThe method was discussed for estimating a comparatively rare occurrence of monitoring data much greater than the average in the field of radiation protection. The features of and the mutual relationships among four types of probability distributions, i. e., normal, log-normal, double-exponential and log-double-exponential, were presented, and their application to various monitoring data of radiation protection was shown. For graphical analysis of empirical distributions the followings were concluded:
1. The upper probabilities are considerably affected by the method of calculating the quantiles and the method of logarithmic transformation of a stochastic variable after a fixed value being added to or subtracted from it to obtain the better straight-line fit on the probability paper.
2. A double-exponential distribution provided a good fit to the annual dose maxima, while a log-double-exponential distribution did to the radioactive contamination maxima in a fixed period of time or in a fixed region of space.
3. The monitoring data arranged in the order of their magnitude were expressed by an exponential function of the order for dose data and by a power function of the order for radioactive contamination data.View full abstractDownload PDF (885K) -
Tatsuo NISHI, Shigeru KUMAZAWA, Masashi ITO, Takao NUMAKUNAI1980 Volume 15 Issue 2 Pages 111-118
Published: 1980
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSThe statistical analyses were made with regard to the distribution of annual radiation doses of the workers in the Japan Atomic Energy Research Institute (JAERI) in order to clarify the characteristics of exposure pattern and to examine the goodness of fit of the data to the theoretical probability distributions.
The following conclusions were obtained.
1) A log-normal distribution provide a good fit to the annual dose distributions.
2) A double exponential distributions provide a good fit to the distributions of annual maximum dose.
3) A log-normal distribution provide a good fit to the distributions of the ratio of annual maximum dose to average one.
4) The annual maximum dose arranged in the order of their magnitude is expressed by an exponential function and the dose is decreased to 1/e with every eleventh.View full abstractDownload PDF (676K) -
Emiko KONISHI, Toru KIKUCHI, Takashi TABARA, Yasuo YOSHIZAWA1980 Volume 15 Issue 2 Pages 119-124
Published: 1980
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSDownload PDF (736K) -
Kazuo WATARI, Kiyoko IMAI, Masami IZAWA, Kiyoshi IWASHIMA1980 Volume 15 Issue 2 Pages 125-127
Published: 1980
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSDownload PDF (233K) -
Tatsuo NISHI, Masashi ITO, Shigeru KUMAZAWA, Takao NUMAKUNAI1980 Volume 15 Issue 2 Pages 129-133
Published: 1980
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSDownload PDF (302K) -
Takashi NAKAMURA, Kazuo ITOH, Toshiaki Yoshimura1980 Volume 15 Issue 2 Pages 135-146
Published: 1980
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSThis work investigated the shielding effect of the building which is indispensable for the accurate evaluation of the population dose of external exposure from natural radiation.
At first, the attenuation coefficients of various building materials were measured and found to agree with the calculated values within 10% errors. The shielding factors of these materials were calculated from the calculated attenuation coefficients and buildup factors.
The shielding factors of the wall, window, roof and floor were calculated separately by settling the model houses and combining the shielding factors of the building materials used, and then the shielding factor of the whole building was obtained by use of the opening fraction of the wall and the fractions of the wall, roof and floorareas to the total floor area.
The influence of the shielding effect of the building is well represented by the occupancy factor which is the ratio of the group doses including that shielding effect to those excluding it. The occupancy factor lies between 0.9 and 1.0 for four specified districts, Tokyo, Osaka, Ibaraki and Nagano.View full abstractDownload PDF (1084K)
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