The results on cosmic rays detected by the gravitational antenna NAUTILUS
have motivated an experiment (RAP) based on a suspended cylindrical bar, which
is made of the same aluminum alloy as NAUTILUS and is exposed to a high energy
electron beam. Mechanical vibrations originate from the local thermal expansion
caused by warming up due to the energy lost by particles crossing the material.
The aim of the experiment is to measure the amplitude of the fundamental
longitudinal vibration at different temperatures. We report on the results
obtained down to a temperature of about 4 K, which agree at the level of about
10% with the predictions of the model describing the underlying physical
process.Comment: RAP experiment, 16 pages, 7 figure
