The pilot experimental study of 14 MeV fast neutron digital radiography

Abstract

14 MeV Fast neutrons has good penetrability and the 14 MeV fast neutron radiography can meet the need of Non-Destructive Test of the structure and lacuna of heavy-massive sample, whose shell is made of heavy metal and in which there are some hydrogen materials, and the study of fast neutron digital radiography just begins in China. By the use of a D-T accelerator, a digital imaging system made up of a fast neutron scintillation screen made of ZnS(Ag) and polypropylene, lens and a scientific grade CCD, the experimental study of fast neutron radiography has been done between 4.3×10 10 -6.8×10 10 n/s of neutron yield. Some 14 MeV fast neutron digital radiographs have been gotten. According to experimental radiographs and their data, the performance of the fast neutron scintillation screen and the basic characters of 14 MeV fast neutron radiography are analyzed, and it is helpful for the further research.fast neutron, digital radiography, experiment, analysis Neutron radiography has proved to be a useful tool in non-destructive testing. Because of the particular features in the interaction of neutrons and nuclides, neutron radiography is a good complementarity for the gamma or X-ray radiography in the following cases:(i) Where hydrogen is involved, even in small amounts.(ii) Where heavy metals or complex materials testing, which gamma or X-ray is unable to penetrate, is required.(iii) Where samples with heavy radiation need to be tested.(iv) Where nuclides which have close atomic number, including specific isotopes, have to be distinguished and investigated.Fast neutrons have higher energy and stronger penetrability than the thermal and cold neutrons. The small fast neutron sources always can be moved conveniently. Therefore fast neutron radiography (FNR) can be used in the testing of massive samples, key subassembly and the local testing of the objects. FNR is a new non-destructive testing method with a prodigious development potential and a variety of industrial applications, especially in the dependability evaluation of nuclear weapons and the antiterrorism detection (To detect the illicit drugs and explosives packed with heavy metals) [1][2][3][4][5][6] . At the same time, 14 MeV fast neutron radiography is also an important technique of ICF (Inertial Confined Fusion).Although a great deal of work has been carried out, FNR still is not a commonly used non-destructive testing method as the relatively mature thermal neutron radiography. That is due to the low detection efficiency of fast neutrons, the large influence of neutron scattering and so on. On account of its variety of applications and technical difficulties, FNR is not only the keystone but also the difficulty in the whole neutron radiography field. Scientists of America started the research of FNR twenty years ago. To the present they just finished an engineering prototype. The actual facility will be put into use in

Hydrogen-Rich 2D Halide Perovskite Scintillators for Fast Neutron Radiography

“…During one fission reaction of 235 U approximately 2.44 neutrons and 6.6 gamma photons are produced on average, 15 while 14 MeV neutrons of a fast neutron accelerator are produced by a fast neutron generator based on the 3 H ( 2 H, n) 4 He reaction during the experiment. 51 Due to the different reaction principles, this process produces fewer γ rays. The Mn-STA 2 PbBr 4 imaging plate (diameter 50 mm) with a thickness of 1135 μm was selected as the scintillation screen (Figure 6a).…”

“…Besides a 2 MeV neutron reaction via the fission reaction of enriched uranium, besides a fission neutron beam, a significant amount of γ radiation is produced. During one fission reaction of 235 U approximately 2.44 neutrons and 6.6 gamma photons are produced on average, while 14 MeV neutrons of a fast neutron accelerator are produced by a fast neutron generator based on the 3 H ( 2 H, n) 4 He reaction during the experiment . Due to the different reaction principles, this process produces fewer γ rays.…”

The Development of a Parameterized Scatter Removal Algorithm for Nuclear Materials Identification System Imaging

“…32 This is largely because of the initial difficulty in capturing the fast neutron response using thermal radiography techniques. E. Tochilin tested fast neutron radiography with traditional film techniques in 1965 and wrote that the poor response of photographic films to neutrons with energies >10 keV presented serious technical difficulties and the buildup of scattered neutrons and induced gammas limit the technique to objects less than a few inches thick.…”

A Novel NDT Scanning System Based on Line Array Fast Neutron Detector and D-T Neutron Source

“…At present, the research on fast neutron radiography is mainly focused on the compact accelerator neutron source. That is because the compact accelerator neutron source is relatively small, and the cost is not high [ 8 , 9 , 10 , 11 , 12 ]. The detectable field of view (FOV) of fast neutron radiography generally does not exceed 350 × 350 mm 2 [ 6 , 9 ], so the single detection range is not large.…”