Toward Neutron Radiography Using Two Arrays of Nb-Based Current-Biased Kinetic Inductance Detectors With 10B Converter Sandwiched In-Between

A superconducting nanowire detector with a ¹⁰B conversion layer is useful for sensing a single neutron at a high operation rate. We use ⁷Li ion and ⁴He ion emitted as two independent heat sources in opposite direction, which are associated with nuclear reaction ¹⁰B(n,⁴He)⁷Li to identify the XV position of neutron arrival. We probe a change rate in the kinetic inductance L_k originating from kinetic inertia of the Cooper pairs. Our detector is different from a well-known microwave kinetic inductance detector and, hence, is named as a current-biased kinetic inductance detector. We use two sets of meanderlines made of Nb nanowires with superconducting readout taps to monitor local signals. In between the X meander and the V meander, we sandwiched a ¹⁰B layer acting as a neutron conversion layer to two charged particles. We succeeded in observing signal induced by nuclear reaction. We plan to build a megapixel neutron imager by coupling 10-bit linear position-sensitive arrays with single-flux quantum circuits to read (X,V) position of neutron arrival in the future.