Vibrational excitation induced by electron beam and cosmic rays in normal and superconductive aluminum bars

Abstract

We report new measurements of the acoustic excitation of an Al5056 superconductive bar when hit by an electron beam, in a previously unexplored temperature range, down to 0.35 K. These data, analyzed together with previous results of the RAP experiment obtained for T > 0.54 K, show a vibrational response enhanced by a factor ∼ 4.9 with respect to that measured in the normal state. This enhancement explains the anomalous large signals due to cosmic rays previously detected in the NAUTILUS gravitational wave detector.

Analysis of 3 years of data from the gravitational wave detectors EXPLORER and NAUTILUS

“…Both detectors are equipped with cosmic ray telescopes, to veto excitations due to large showers [15][16][17]. The two telescopes rely on different technologies (scintillators for Explorer, streamer tubes for Nautilus) but both provide a monitor of comparable effectiveness and a continuous check of the antenna sensitivity [18,19].…”