Neutron detection by superconducting tunnel junctions on a LiBO single-crystal absorber

Nakamura, Tatsuya; Katagiri, Masaki; Ukibe, Masahiro*; Ikeuchi, Takashi*; Okubo, Masataka*

Nuclear Instruments and Methods in Physics Research A, 520(1-3), p.67 - 69, 2004/03

https://doi.org/10.1016/j.nima.2003.11.222

We succeeded in detecting neutrons using superconducting tunnel junctions (STJs) fabricated on a single crystal of LiBO. Neutrons are captured in the crystal by the nuclear reactions Li + n T+ + 4.78 MeV and B + n Li + + 2.3 MeV, and generated phonons propagate in the absorber and are measured by the STJs. We selected a single crystal of LiBO as the absorber material because of properties such as the large neutron cross-section of Li and B, low -ray sensitivity, short particle range in the substrate, and fast phonon velocity. Series-connected or multiple STJs on the crystal would enable two-dimensional neutron imaging with high detection efficiency, low gamma-ray background, and a high spatial resolution of a few microns. We demonstrate neutron detection by the STJs and show their X-ray response and neutron detection. The correlation in pulse heights between two junctions located 1.3mm apart clearly indicates the possibility of neutron imaging.