Wide-energy-spectrum white-light neutron resonance photographic detector and detection method

Abstract

The invention discloses a wide-energy-spectrum white-light neutron resonance photographic detector and detection method. According to the detector, the interior of a detector body is a cavity structure; an incident window and a rear window are respectively arranged at two ends; a neutron-sensitive MCP, a common high-performance MCP and a position-sensitive anode strip array circuit board are arranged in a direction from the incident window to the rear window; a vacuum extraction opening is formed in the side wall, close to the rear window, of the detector body. The position-sensitive anode strip array circuit board is connected with a signal extraction electrode, and one end of the signal extraction electrode is arranged on the side wall of the detector body. The detection method comprisesthe following steps: injecting a neutron beam from the incident window; reacting with a boron element in the neutron-sensitive MCP to generate charged particles; exciting electrons by the charged particles; after electron cascade amplification generation by the electrons through the common high-performance MCP, making a drift to the position-sensitive anode strip array circuit board to form an electric pulse signal; and then performing outputting through the signal extraction electrode. Therefore, resonance photography for distinguishing all resonance nuclides on a high-intensity wide-energy-spectrum neutron source can be realized.

Description

technical field [0001] The invention relates to the technical field of neutron resonance imaging, in particular to a wide-energy-spectrum white-light neutron resonance camera detector and a detection method. Background technique [0002] The neutron-matter interaction is closely related to the nuclear structure of the substance. The cross-sections of neutrons with different energies on different nuclides are very different, and are usually accompanied by reflection nuclides in the epithermal-fast neutron energy region (0.5eV-10MeV). Formants of characteristic information. Theoretically, neutron resonance imaging technology not only gives the grayscale spectrum of conventional transmission photography, but also gives the nuclide composition of the measured object through resonance peak analysis, and can also give the position distribution image of each resonant nuclide. , industrial testing and social security and many other fields have broad application prospects. [0003]...

AI Technical Summary

Problems solved by technology

[0005] Compared with thermal neutron transmission imaging, white light neutron resonance imaging requires the detector system to meet several key indicators such as position resolution, energy resolution, detection efficiency and spectral response range of wide-energy neutron measurement, while high-energy neutron The detection efficiency of neutrons is much lower than that of low-energy neutrons, so it is very difficult to realize this detection technology, and it is still in the exploration stage at home and abroad.

[0006] In 2012, Mor et al. used a liquid-scintillation-filled capillary array plus a multi-anode photomultiplier tube (PMT) scheme to perform fast neutron imaging, but the position resolution of this scintillation array-based method is usually on the order of millimeters, which is very important for imaging. It is difficult to achieve the desired effect

Further improving the position resolution requires reducing the wire diameter and increasing the number of photomultiplier devices and electronic readout channels, which not only reduces the optical signal collection efficiency and affects its detection possibility, but also increases the difficulty of scintillation array clustering and the docking of photomultiplier devices. Moreover, the cost, volume and power consumption of multi-channel signal reading electronics are very huge, which greatly increases its practical cost. Therefore, this solution has basically not been successfully applied in neutron resonance imaging experiments so far.

[0007] In 2015, Dangendorf et al. used a hydrogen-containing material as a neutron conversion layer combined with a position-sensitive gas detector (GEM) to try fast neutron resonance imaging. Although a good transmission spectrum was obtained, the expected C element distribution image did not appear.

In recent years, the combination of Timepix and boron-doped microchannel plate (MCP) has achieved great success in epithermal neutron resonance photography, but it is limited by its technical characteristics (such as: on the one hand, the time resolution of Timepix is ​​low (about 100ns ), on the other hand is also the most critical, Timepix needs to be placed on the neutron beamline together with the detector, and as a highly integrated analog-digital hybrid chip, its radiation resistance is poor), its application is currently limited to Epithermal neutron energy region (<100eV), has not been successfully applied to fast neutron imaging

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