Measurement of the thermal expansion coefficient of an Al-Mg alloy at ultra-low temperatures

TL;DR

This study measures the thermal expansion coefficient of an Al-Mg alloy at ultra-low temperatures using a suspended bar experiment that detects oscillation amplitudes caused by electron beam interactions.

Contribution

It introduces an experimental method combining oscillation measurements and specific heat data to determine the thermal expansion at ultra-low temperatures.

Findings

Thermal expansion coefficient of Al-Mg alloy measured at ultra-low temperatures.

Method effectively links oscillation amplitude to material expansion properties.

Results provide insights into alloy behavior near superconducting transition.

Abstract

We describe a result coming from an experiment based on an Al-Mg alloy (~ 5% Mg) suspended bar hit by an electron beam and operated above and below the termperature of transition from superconducting to normal state of the material. The amplitude of the bar first longitudinal mode of oscillation, excited by the beam interacting with the bulk, and the energy deposited by the beam in the bar are the quantities measured by the experiment. These quantities, inserted in the equations describing the mechanism of the mode excitation and complemented by an independent measurement of the specific heat, allow us to determine the linear expansion coefficient of the material.