Numerical Modeling and Experimental Demonstration of Pulsed Charge Control for the Space Inertial Sensor used in LISA

Henri Inchauspé; Taiwo Olatunde; Stephen Apple; Samantha Parry; Ben Letson; Nicholas Turetta; Guido Mueller; Peter J Wass; John W Conklin

doi:10.1103/physrevd.102.042002

arXiv · 2005.00917

Numerical Modeling and Experimental Demonstration of Pulsed Charge Control for the Space Inertial Sensor used in LISA

Henri Inchauspé·Taiwo Olatunde·Stephen Apple·Samantha Parry·Ben Letson·Nicholas Turetta·Guido Mueller·Peter J Wass·John W Conklin

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Abstract

Electrostatic charge control of isolated free-falling test masses is a key enabling technology for space-based gravitational missions. Contact-free electrostatic charge control can be achieved using photoelectron emission from metal surfaces under illumination with deep UV light. A contact-free method minimizes force disturbances that can perturb measurements or interrupt science operations. In this paper we present charge control experiments using a gravitational reference sensor geometry relevant to the Laser Interferometer Space Antenna (LISA) gravitational wave observatory in a torsion pendulum apparatus. We use a UV LED light source to control the test mass potential, taking advantage of their high bandwidth to phase-lock the light output to 100kHz electric fields used for capacitive position sensing of the test mass. We demonstrate charge-rate and test mass potential control by adjustment of the phase of the light with respect to the electric field. We present a simple physics-based model of the discharging process which explains our experimental results in terms of the UV light distribution in the sensor, surface work functions and quantum yields. A robust fitting method is used to determine the best-fit physical parameters of the model that describe the system

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Henri Inchauspé, Taiwo Olatunde, Stephen Apple, Samantha Parry, Ben Letson, Nicholas Turetta, Guido Mueller, Peter J Wass, John W Conklin. 2020-05-02. Numerical Modeling and Experimental Demonstration of Pulsed Charge Control for the Space Inertial Sensor used in LISA. https://doi.org/10.1103/physrevd.102.042002

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