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

TL;DR

This study measures how electron beams and cosmic rays excite vibrations in aluminum bars at very low temperatures, revealing a significant increase in response when the material is superconductive, which explains previous cosmic ray detection anomalies.

Contribution

It provides new low-temperature measurements of vibrational excitation in superconductive aluminum, demonstrating a nearly fivefold enhancement over the normal state, advancing understanding of cosmic ray interactions.

Findings

Vibrational response is enhanced by a factor of 4.9 in the superconductive state.

Data explains large cosmic ray signals in gravitational wave detectors.

Measurements extend to temperatures as low as 0.35 K.

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.