摘要:

By using 14 MeV neutron flux of 3.5 × 1010n/cm2· s, the activities of the activated nuclides in both ferrosilicon alloy (from Kima-Aswan Company) and black sand samples (from the mouth of Damietta, North of Egyptian Delta), were measured. The rate dose of natural gamma-activities arising from Th-232 in the black sand area was calculated.

ISSN:0021-1915    

DOI:10.1080/10256019108622508

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

A comparative study was made for measuring neutron depth dose distribution in a water phantom by means of different solid state nuclear track detectors. The used detectors were Makrofol, CR-39 and LR-115 with threshold energies of 1 and 0.1 MeV, respectively. Two exposure positions were used, the source in contact with the surface and at 30 cm from the phantom surface. The fluence distribution of252Cf as a function of distance in air and in the water phantom were investigated. It was found that the neutron build up factor depends on the irradiation geometry, its values were 1.7 and 1.4 for both exposure positions. These results are in good agreement with the calculated results given in literature. The neutron attenuation and relaxation length had been also determined.

ISSN:0021-1915    

DOI:10.1080/10256019108622509

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

LiF (600 and 700) and plastic detector were used for measuring fast and thermal neutrons and γ-ray doses from252Cf source in tissue equivalent phantom. Conversion factors as well as related quality factors were used for absorbed and equivalent dose calculations. Two exposure positions were used: source at 30 cm and in contact with phatnom surface. The contribution of thermal and fast neutrons in both absorbed dose and equivalent dose reaches a maximum value at 3.5 cm while the maximum for γ-ray is at 8.5 cm. The build up and attenuation in tissue and the corresponding relaxation length were evaluated.

ISSN:0021-1915    

DOI:10.1080/10256019108622510

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Track etch rate characteristics of CR-39 plastic detector exposed to28Si ions of 670 MeV energy have been investigated. Experimental results were obtained in terms of frequency distribution of the track diameter, track density and bulk etching rate. A dependence of the mean track diameter on energy was found. The application of the radiation effect of heavy ions on CR-39 in the field of radiation detection and dosimetry are discussed. Results indicated that it is possible to produce etchable tracks of28Si in this energy range in CR-39. We also report the etching characteristics of these tracks in the CR-39 detector.

ISSN:0021-1915    

DOI:10.1080/10256019108622511

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

CR-39 plastic nuclear track detector is used to measure the fraction of alpha-particle tracks due to radon daughters activities plated-out on the internal walls of a cylindrical-shaped plastic can. Radium chloride solution is used as a radon source, the exposure time is ranged from 4 hours to 3 days. To assess the percentage of plate-out effect on CR-39 nuclear track detector, two different methods were used. In one experiment, a few circular parallel pairs of CR-39 sheets were hanged in the can device. In the other experiment, the estimation of the plate-out effect has been performed, after exposure to the radon source, by detecting tracks with a second unexposed sheet placed in close contact to the exposed wall and detectors. In the two methods, it was found that the chemically etched tracks related to plated-out activities contribute about 50% of the measured alpha-particles tracks.

ISSN:0021-1915    

DOI:10.1080/10256019108622512

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The etch-induction time, Tc, is measured for α-particles in CR-39 plastic track detector and the etch-critical time, Tc, is calculated for α-particles in CR-39 detector as a function of α-energy, E, and incident angle, 0. The etch-induction time was found to be independent of dip angle and directly proportional to the α-particle energy in the range from 1–6.1 MeV. The etch-critical time was found to be zero for angles greater than the critical angle, 0c, whereas at angles less than 0c, the etch-induction time, Ti, was increased by the value of Tc.

ISSN:0021-1915    

DOI:10.1080/10256019108622513

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The alpha particle response which is characteristic of polycarbonate detectors CR-39 has been investigated. The track diameter as a function of alpha energy in the range from 5.1–22.2 MeV was examined. The mean track diameter or size of the tracks are found to be energy dependent which decreases as alpha energy increases with a trend at about 14 MeV alpha energy. With regard to the spectroscopy of alpha from track radii, it was stated that the discrimination of lower alpha energies shows better results than the high energies for the present etching condition.

ISSN:0021-1915    

DOI:10.1080/10256019108622514

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

ISSN:0021-1915    

DOI:10.1080/10256019108622515

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor