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Dosimetry

Miscellaneous:

Abstract

The methods of dosimetry used for investigation of the doses received by the individuals exposed in the Yugoslav accident were essentially those used in connection with the Oak Ridge Y-12 accident. An outline of the general scheme is as follows: When fast neutrons enter the human body, most of these are moderated to thermal energy and a small fraction of these are captured by a (n, {gamma}) process in Na{sup 23}, giving rise to Na{sup 24}, which by virtue of its emission of high-energy gamma rays with a half life of 14.8 h, is easily detected. It has been shown that the probability of capture, making Na{sup 24}, is not a strong function of the energy of the fast neutrons and that the probability of capture for neutrons is higher in the fast region than in the thermal region. Thus, the uniform distribution of Na{sup 23} in the human body provides an excellent means of normalizing the neutron exposure of an individual. in particular, for a given neutron energy spectrum the fast neutron dose is proportional to the ratio Na{sup 24}/Na{sup 23} in the body or in the blood system. This method of normalization is quite important in the dosimetry  More>>
Authors:
Hurst, G S; Ritchie, R H; Sanders, F W; Reinhardt, P W; Auxier, J A; Wagner, E B; Callihan, A D; Morgan, K Z [1] 
  1. Health Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN (United States)
Publication Date:
Mar 01, 1962
Product Type:
Miscellaneous
Report Number:
STI/DOC-10/6
Resource Relation:
Other Information: 19 figs, 13 tabs; PBD: Mar 1962; Related Information: In: The Vinca dosimetry experiment, Technical reports seriesno. 6, 64 pages.
Subject:
61 RADIATION PROTECTION AND DOSIMETRY; BOLTZMANN EQUATION; DELAYED GAMMA RADIATION; FISSION PRODUCTS; GAMMA DOSIMETRY; LETHAL IRRADIATION; MULTIGROUP THEORY; NEUTRON DOSIMETRY; NEUTRON LEAKAGE; NEUTRON REACTIONS; NEUTRON TRANSPORT THEORY; PHANTOMS; PROMPT GAMMA RADIATION; R-B REACTOR; SODIUM 23 TARGET; SODIUM 24; Y-12 PLANT
OSTI ID:
20385808
Research Organizations:
International Atomic Energy Agency, Vienna (Austria)
Country of Origin:
IAEA
Language:
English
Other Identifying Numbers:
TRN: XA0302286065321
Submitting Site:
INIS
Size:
page(s) 25-45
Announcement Date:

Miscellaneous:

Citation Formats

Hurst, G S, Ritchie, R H, Sanders, F W, Reinhardt, P W, Auxier, J A, Wagner, E B, Callihan, A D, and Morgan, K Z. Dosimetry. IAEA: N. p., 1962. Web.
Hurst, G S, Ritchie, R H, Sanders, F W, Reinhardt, P W, Auxier, J A, Wagner, E B, Callihan, A D, & Morgan, K Z. Dosimetry. IAEA.
Hurst, G S, Ritchie, R H, Sanders, F W, Reinhardt, P W, Auxier, J A, Wagner, E B, Callihan, A D, and Morgan, K Z. 1962. "Dosimetry." IAEA.
@misc{etde_20385808,
title = {Dosimetry}
author = {Hurst, G S, Ritchie, R H, Sanders, F W, Reinhardt, P W, Auxier, J A, Wagner, E B, Callihan, A D, and Morgan, K Z}
abstractNote = {The methods of dosimetry used for investigation of the doses received by the individuals exposed in the Yugoslav accident were essentially those used in connection with the Oak Ridge Y-12 accident. An outline of the general scheme is as follows: When fast neutrons enter the human body, most of these are moderated to thermal energy and a small fraction of these are captured by a (n, {gamma}) process in Na{sup 23}, giving rise to Na{sup 24}, which by virtue of its emission of high-energy gamma rays with a half life of 14.8 h, is easily detected. It has been shown that the probability of capture, making Na{sup 24}, is not a strong function of the energy of the fast neutrons and that the probability of capture for neutrons is higher in the fast region than in the thermal region. Thus, the uniform distribution of Na{sup 23} in the human body provides an excellent means of normalizing the neutron exposure of an individual. in particular, for a given neutron energy spectrum the fast neutron dose is proportional to the ratio Na{sup 24}/Na{sup 23} in the body or in the blood system. This method of normalization is quite important in the dosimetry of radiation accidents since no assumptions need be made about the exact location of an individual at the time of the energy release. The importance of this fact can be made clear by reference to the Y-12 accident where it was shown by calculation of the neutron dose based on the known number of fissions and the stated location of the individual that one of the surviving individuals would have received a dose several times the lethal value. To accomplish the measurements described, the zero power R{sub B} reactor was operated in two ranges of power level, 'low' power and 'high 'power. Neutron leakage spectrum was obtained by multigroup approximation of the Boltzman transport equation. Prompt gamma rays from fission products, from capture in the moderator and fuel cladding as well as in tank walls are given. A summary of the 4{pi}R{sup 2} dose from different sources is given. Calculation results of the gamma dose leakage is shown in appendix 3A; studies of Na{sup 24} activation in man-shaped phantoms are presented in Appendix 3B; intercomparison of French and American Na{sup 24} is given in Appendix 3C; study of the neutron flux distribution in the R-B reactor room is presented in Appendix 3D.}
place = {IAEA}
year = {1962}
month = {Mar}
}