SQUID-based accelerometer and final concept for testing the equivalence principle at the drop tower

Abstract

The Weak Equivalence Principle (WEP) is a fundamental principle in physics. Although the most obvious way to proof the equivalence of inertial and gravitational mass is to compare the motion of 2 bodies during free fall, the most precise experiments were made by means of torsion balances (Δa/a=10−12). The few experiments, which tried to test the EP directly on freely falling bodies reached an accuracy of about 10−10, limited by rather short free falling periods. The Drop Tower Bremen provides a much longer time for free fall and together with high sensitive SQUID-based displacement sensors at low temperatures, it seems possible to achieve a better accuracy doing a WEP test at the Drop Tower Bremen. Here we will present the first results of our pre-tests to find an optimum experimental design for a freely falling accelerometer.