Non-Destructive post-irradiation examination results of the first modern fueled experiments in TREAT

Boron-Based Neutron Scintillator Screens for Neutron Imaging

“…First, the thermal neutron cross-section of 10 B (3840 b) is approximately four times greater than that of 6 Li (980 b), as shown in Figure 1, which should increase the neutron detection efficiency for a comparable 6 Li-based screen. Second, the daughter products created by neutron absorption of 10 B have less total energy (2.31 MeV or 2.79 MeV) than those of 6 Li (4.78 MeV) and Gd (7.937 MeV or 8.536 MeV), and the lower energy from a 10 B(n,α) 7 Li reaction is distributed on heavier daughter products compared to a 6 Li(n,α) 3 H reaction. The lower energy and larger size of the daughter products reduces the range the daughter products will travel, a fundamental limiting factor of a screen's spatial resolution, potentially enabling borated scintillator screens to exhibit higher spatial resolution compared to the screens created with 6 Li or Gd.…”

“…Neutron imaging is a nondestructive examination technique that measures neutron transmission to examine a sample’s internal structure. This technique has been used in a variety of studies, including those of nuclear fuels and materials [ 1 , 2 , 3 , 4 , 5 , 6 ], cultural heritage objects [ 7 , 8 , 9 ], fuel cells [ 10 , 11 , 12 , 13 , 14 ], turbine blades [ 15 , 16 , 17 ], and many others. Digital neutron imaging techniques are now an essential capability for any state-of-the-art neutron imaging facility [ 18 ].…”

“…A critical component of digital neutron imaging systems is the neutron scintillator, because the scintillator dictates the neutron capture efficiency and is a limiting factor in spatial resolution. Common scintillator screens for thermal and cold neutron imaging utilize either a 6 Li(n,α) 3 H reaction due to its large neutron absorption cross-section and relatively large reaction energy, or a Gd(n,γ + ICe−) reaction because of gadolinium's high neutron absorption cross-section [19][20][21][22][23]. Although these scintillator screens are the state of the art in the digital neutron imaging community, the continual improvement of neutron scintillators are necessary to meet the ever-higher user demands for increased spatial resolution to examine smaller samples and increased detection efficiency to decrease measurement time.…”

“…Boron-based screens offer a promising alternative to existing 6 Li-and Gd-based neutron scintillator screens for a number of reasons. First, the thermal neutron cross-section of 10 B (3840 b) is approximately four times greater than that of 6 Li (980 b), as shown in Figure 1, which should increase the neutron detection efficiency for a comparable 6 Li-based screen.…”

“…Boron-based screens offer a promising alternative to existing 6 Li-and Gd-based neutron scintillator screens for a number of reasons. First, the thermal neutron cross-section of 10 B (3840 b) is approximately four times greater than that of 6 Li (980 b), as shown in Figure 1, which should increase the neutron detection efficiency for a comparable 6 Li-based screen. Second, the daughter products created by neutron absorption of 10 B have less total energy (2.31 MeV or 2.79 MeV) than those of 6 Li (4.78 MeV) and Gd (7.937 MeV or 8.536 MeV), and the lower energy from a 10 B(n,α) 7 Li reaction is distributed on heavier daughter products compared to a 6 Li(n,α) 3 H reaction.…”