Pseudoplane-wave gravitational calibrator for gravitational wave observatories

A vacuum-compatible cylindrical inertial rotation sensor with picoradian sensitivity

“…Hz at 1.5 Hz. This design continues our previous sensor development 2,7,10 and shares many qualities with prior designs. The sensor is made of low-outgassing ultra-high-vacuum compatible materials and can be operated and centered remotely.…”

“…A detailed description of the dynamics of flexure-based inertial rotation sensors can be found in Ross. 2 Figure 2 shows a picture of the CRS prototype. The proof-mass was machined out of a single monolithic piece of aluminum to maximize thermal uniformity.…”

“…Details of the centering mechanism can be found in Ross. 2 Running wires to the proof-mass to power a motor would be significantly stiffer than the flexures and ruin the performance of the sensor. To alleviate this issue, when adjustments are needed, a motor attached to the support structure turns the screw.…”

“…This noise level is a factor of 50 improvement over our group's previous devices. 2 The improved performance is primarily due to the deployment of high sensitivity interferometer readouts 11 with minor improvements at low frequencies due to the monolithic cylindrical test mass.…”

“…Sensing minute rotations has long drawn interest from a variety of scientific fields. Recently, rotation sensors with sub-nrad sensitivities have been pursued to improve the seismic isolation systems of gravitational wave observatories 1,2 and to allow novel measurements of the rotational component of seismic waves. 3 Multiple devices now reach this sensitivity including ring-laser gyros [4][5][6] and flexure-based inertial rotation sensors.…”