A new class of equivalence principle test masses, with application to SR-POEM

摘要

We describe a new class of test masses (TMs) for use in a Galilean test of the equivalence principle, principally in space. These TMs have n ≥ 2 vertical bars that are joined by an off-center connector. A pair of TMs will be positioned to have interleaved bars. For n ≥ 3, the principal moments of inertia of a TM can be made equal. With their centers of mass aligned, a TM pair shows decreasing susceptibility to differential acceleration from local mass as n increases. For the Sounding Rocket based Principle Of Equivalence Measurement (SR-POEM), the mission requirements are well met with n = 3, but not met with n = 2. For a 1 kg SR-POEM TM, vibration frequencies can be made to be above 1 kHz and thus not interfere with the operation of the TM suspension system. The SRPOEM housing supports electrodes for a set of capacitance gauges that observes all six kinematic degrees of freedom of each TM.