A fast, self-recovering superconducting strip particle detector made with granular tungsten

Abstract

The ability of detectors to automatically recover (self-recovery) in a short period of time after sensing a particle is a very valuable advantage for their use as microvertex detectors at high energy particle colliders. Using a superconducting strip detector made of granular tungsten, we have observed such behavior with pulse amplitudes of few 100 μV and recovery times fo 10–50 ns. A 1.8 μm wide thin film was used to detect the superconducting-to-normal transitions induced by the absorption of ⁵⁵Fe, 6 keV X-rays. For high bias currents the detector did not self-recover and a constant efficiency estimated to ∼65% was found, but with good indications that such a rate would persist in the self-recovery mode at lower bias currents. The threshold between self-recovering and propagating hotspots is discussed within the thermal propagation model, developed previously for normal regions which bridge the width of the strip. These results also confirm the potential applications of superconducting strips for high resolution X-rays detectors.