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[en] The object of this note is to describe the application of microdosimetric methods to the investigation of the radiation quality of the neutron field at the Gray Laboratory facility, Mount Vernon Hospital. (author)
Journal
[en] Here, we present the design, characterization, and testing of a laboratory prototype radiological search and localization system. The system, based on time-encoded imaging, uses the attenuation signature of neutrons in time, induced by the geometrical layout and motion of the system. We have demonstrated the ability to detect a ~1 mCi252 Cf radiological source at 100 m standoff with 90% detection efficiency and 10% false positives against background in 12 min. As a result, this same detection efficiency is met at 15 s for a 40 m standoff, and 1.2 s for a 20 m standoff.
Journal
Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment; ISSN 0168-9002; 
; v. 877; 9 p
; v. 877; 9 p
[en] Knowledge of the absolute activity of 58Co sources is of great value for determining the fast-neutron flux in a reactor. The authors measure this activity from β+-γ de-'excitation with a coincidence device: β+-signal obtained from the rapid coincidence (resolving time 6 ns) of annihilation gammas is made to coincide (resolving time 0.6 μs) with the signal for 810-keV gammas. By this method it is easily possible to measure activity in a range extending from several 104 to several 106 disintegrations per second. Under the best conditions, which are obtained at several 105 disintegrations/s, an accuracy of 1% is reached: Intercalibrations carried out between 1963 and 1965 showed good agreement between different laboratories. (author)
[fr]
La connaissance de l'activité absolue de sources de 58Co est d'un grand intérêt pour la détermination de flux de neutrons rapides dans un réacteur. Les auteurs effectuent la mesure de cette activité par la voie de désexcitation β+-γ au moyen d'un dispositif à coïncidences: un signal β+-, obtenu par la mise en coïncidence rapide (temps de résolution 6 ns) des γ d'annihilation est mis en coïncidence (temps de résolution 0,6 μs) avec le signal des y de 810 keV. La gamme des activités mesurables aisément par cette méthode s'étend de quelque 104 à quelque 106 désint./s. Dans les meilleures conditions, réalisées pour quelque 105 désint. /s, la précision atteinte est de l'ordre de 1%. Un bon accord a été obtenu lors de comparaisons interlaboratoires effectuées de 1963 a1965. (author)Source
International Atomic Energy Agency, Vienna (Austria); 763 p; Mar 1967; p. 223-233; Symposium on Standardization of Radionuclides; Vienna (Austria); 10-14 Oct 1966; IAEA-SM--79/13; ISSN 0074-1884; ; 13 refs., 3 figs.
; 13 refs., 3 figs.
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