High-Resolution Thermal Neutron Imaging With ¹⁰Boron/CsI:Tl Scintillator Screen

Abstract

Abstract-High resolution neutron imaging is difficult, due to the low-light output of neutron scintillators, and the spread of light within common neutron-sensitive scintillators as well as the spread of intermediate particles occurring during the detection process. To address this issue, we have developed a high-resolution scintillator for neutron imaging by combining enriched 10 B with the well-known CsI:Tl scintillator films. CsI:Tl has excellent properties for X-ray imaging applications, due to a high light yield of 60,000 photons/MeV, and high spatial resolution, which derives from its microcolumnar structure, which channels scintillation light to the photodetector. To enable CsI:Tl to detect neutrons, 10 B (96% enriched) was deposited by electron-beam directly onto the CsI:Tl film, making a layered scintillator structure in which the alphas produced by the neutron interaction with 10 B are detected in the CsI:Tl. The 10 B layer was approximately 3 µm thick, while the thickness of the CsI:Tl film was 11 µm. These novel layered scintillators were integrated into the high-resolution neutron imaging detector ('PSI Neutron Microscope') at the POLDI beamline at the Paul Scherer Institute (PSI). With our 10 B/CsI:Tl scintillator we were able to achieve a spatial resolution down to 9 µm. To demonstrate the effectiveness of the layered scintillator, we present results obtained by thermal neutron imaging as well as high-resolution neutron computed tomography. Finally, we believe there is considerable scope for future optimization of the performance of this system.

Determination of the Spatial Resolution in the Case of Imaging Magnetic Fields by Polarized Neutrons

“…[24]. In 2014 the spatial resolution in neutron imaging reached with 7.8 µm = 63.2 line pairs/mm a level, which is comparable with X-ray imaging, [25]; however, today already a resolution of X-ray imaging is obtained [15,20,21,[26][27][28].…”

Advances in nuclear detection and readout techniques

“…A. Gueorguiev and others have developed a new technology that combines inorganic scintillator (CLYC) with an organic scintillator matrix (methyl methacrylate, PMMA) to achieve simultaneous detection of fast neutrons, thermal neutrons, and -rays. Figure 85 illustrates the structure of this composite detector [363].…”

Boron-Based Neutron Scintillator Screens for Neutron Imaging

“…However, Nakamura et al’s work [ 38 ] suggests smaller boron particles may increase light output performance. More recent efforts by other colleagues in the neutron imaging field have recently explored using 10 B/CsI:Tl scintillator screens for neutron imaging [ 39 ].…”