Apparatus and method for neutron detection with neutron-absorbing calorimetric gamma detectors

Abstract

The invention refers to an apparatus for detecting neutron radiation, preferably thermal neutrons, comprising a gamma ray scintillator, said scintillator comprising an inorganic material with an attenuation length Lg of less than 10 cm, preferably less than 5 cm for gamma rays of 5 MeV energy in order to provide for high gamma ray stopping power for energetic gamma rays within the gamma ray scintillator, the gamma ray scintillator further comprising components with a product of neutron capture cross section and concentration leading to an absorption length Ln for thermal neutrons which is larger than 0,5 cm but smaller than five times the attenuation length Lg, preferably smaller than two times the attenuation length Lg for 5 MeV gammas in the said scintillator, the neutron absorbing components of the gamma ray scintillator releasing the energy deployed in the excited nuclei after neutron capture mainly via gamma radiation, the gamma ray scintillator having a diameter or edge length of at least 50% of Lg, preferably of at least Lg, in order to absorb an essential part of the gamma ray energy released after neutron capture in the scintillator, the apparatus further comprising a light detector, optically coupled to the gamma ray scintillator in order to detect the amount of light in the gamma ray scintillator, the apparatus further comprising an evaluation device coupled to the light detector, said device being able to determine the amount of light, detected by the light detector for one scintillation event, that amount being in a known relation to the energy deployed by gamma radiation in the gamma ray scintillator, where the evaluation device is configured to classify detected radiation as neutrons when the measured total gamma energy Esum is above 2,614 MeV.

Description

technical field [0001] The present invention relates to a device for detecting neutron radiation, preferably thermal (slow) neutrons, using a gamma ray scintillator for indirect detection. Background technique [0002] Although there is a wide variety of methods and equipment available for neutron detection, it remains common in most applications requiring the most efficient neutron counting at the lowest cost. 3 The main pipe. However, it is expected 3 He is in short supply, making a need for a substitute. [0003] Such alternative detectors are known in the prior art. Knoll, Radiation Detection and Measurement, 3rd Edition, 2000, p. 506 states that all common reactions used to detect neutrons are reactions with the emission of charged particles. More specifically, possible reaction products for detection are recoil nuclei (mainly protons), tritons, alpha particles and fission fragments. However gamma rays following neutron capture reactions are used in some specialize...

AI Technical Summary

Problems solved by technology

It is therefore necessary to measure this single decay very accurately in order to achieve at least reasonable results, thus greatly increasing the technical complexity and associated costs

In addition, it is difficult if not impossible to distinguish charged particle radiation (e.g. charged particle radiation of cosmic origin) with detectors as disclosed by Bell

[0011] In summary, the known medium The sub-detector concept is unmatched by 3 he tube competition

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