Plastic scintillator doped with neutron-sensitive material lithium and method thereof for measuring thermal neutrons

Abstract

The invention belongs to the field of radiation measurement, and particularly relates to a plastic scintillator doped with the neutron-sensitive material lithium and a method thereof for measuring thermal neutrons. According to the invention, lithium-contained raw materials are added into the plastic scintillator. The lithium-doped plastic scintillator and a photomultiplier tube are connected and are sealed inside an opaque housing so as to form a probe. The probe is placed in a measurement environment and the nuclear reaction occurs between incident neutrons and the lithium-contained raw materials in the plastic scintillator, so that the materials are in an excited state. During de-excitation, photons are sent out. The number of photons is proportional to the number of incident neutrons. Meanwhile, through recording the electrical impulses semaphore of the photomultiplier tube per unit time, the neutron fluence can be calculated, so that the measurement of the neutron fluence is realized. The neutron fluence is multiplied by a fluence-dose conversion coefficient to obtain the neutron dose equivalent. The plastic scintillator and the method are low in cost, wide in application range and high in detection efficiency.

Description

technical field [0001] The invention belongs to the field of radiation measurement, in particular to a plastic scintillator doped with a neutron-sensitive material lithium and a method for measuring thermal neutrons. Background technique [0002] Plastic scintillators are generally made of polystyrene as a matrix, mixed with other organic additives as scintillating substances, and made of wave shifting agents. It has high detection efficiency, high light output, narrow signal pulse width, good processability, Due to the advantages of strong environmental adaptability, stable mechanical properties, and low cost, it is widely used in radiation measurement work. However, since the main components of plastic scintillators are C, H, and O, their interaction with neutrons is relatively low, and generally cannot It is directly used in the field of neutron monitoring. Therefore, when detecting neutrons, other materials need to be doped or embedded to increase the output of optical s...

AI Technical Summary

Problems solved by technology

[0003] Since the ZnS:Ag film is opaque, the method of embedding the ZnS:Ag film in the plastic scintillator will lose a lot of photons, resulting in a decrease in detection efficiency and sensitivity

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