Radiation detection with a metastable superconducting detector composed of nonspherical grains

Abstract Differential superheating curves at 385 mK of an Al grain suspension, with dimensions of the order of 5–15 μm and ellipsoidal geometry at 20% volume filling factor, indicate a majority of the transitions to occur from a metastable state and that these grains are thermally-nucleated by energy depositions of 6 keV X-rays. These results run counter to established convention that only the most uniform, spherical grains are required in detector fabrication.