EFFECT OF BEAM SPECTRUM ON QUANTITATIVENE SS OF COLD NEUTRON COMPUTED-TOMOGRAPHY

Citation
M. Oda et al., EFFECT OF BEAM SPECTRUM ON QUANTITATIVENE SS OF COLD NEUTRON COMPUTED-TOMOGRAPHY, Nippon Genshiryoku Gakkaishi, 39(8), 1997, pp. 647-656
Citations number
18
Language
GIAPPONESE
art.tipo
Article
Categorie Soggetti
Nuclear Sciences & Tecnology
ISSN journal
0004-7120
Volume
39
Issue
8
Year of publication
1997
Pages
647 - 656
Database
ISI
SICI code
0004-7120(1997)39:8<647:EOBSOQ>2.0.ZU;2-3
Abstract
In case of radiography by a cold neutron beam having a continuous beam spectrum, neutron attenuation coefficients of many materials decrease with increasing the transmitting path length. As a result, quantitati ve analyses, such as determining the composition and density of the ob ject quantitatively, with cold neutron computed tomography (CN-CT) has been difficult. In order to improve quantitativeness of CN-CT, we exa mined two procedures for reducing the effect of the thickness-dependen t attenuation coefficient, and confirmed their effectiveness experimen tally. One procedure is modifying projected images by using the neutro n transmission curve as a kind of calibration curve, which is called t he inverse function method. Another, the spectrum-narrowing method, is depressing change of the attenuation coefficient by making the width of the neutron beam spectrum narrower with a neutron filter. Each proc edure was demonstrated experimentally to enable quantitative CN-CT. Th e inverse function method is simple, but it emphasizes noises of the p rojected image in, especially, the low neutron transmittance region. T he spectrum-narrowing method has an advantage of obtaining the simple exponential attenuation property on neutron radiograph, though the lon ger exposure time was required because of beam intensity loss.