Uploaded July 2022 | Updated September 2026, 2 hours ago
Cosmic rays, solar energetic particles, and other forms of radiation tend to accumulate electric charges on isolated objects placed in the space environment. This is a well-established issue that, if not addressed, could spoil the performance of future space-borne gravitational wave detectors, such as LISA.
The precursor mission LISA Pathfinder has proven that a contactless charge management system that employs UV radiation produced by Hg-lamps can successfully control the test mass charge. LISA Pathfinder applied a periodic discharge strategy: once the TM charge exceeded a threshold (~every two weeks), it was illuminated to bring its charge within the allowed range.
In LISA, it is envisioned to use UV-LEDs as light sources for the charge management system, which brings several advantages with respect to Hg-lamps in terms of reliability, robustness, weight-saving, and, more importantly, flexibility in the illumination scheme.
Indeed, the illumination with UV-LEDs can be synchronized with the TM injection voltages and this allows to reach bipolar discharge and precisely control the test mass equilibrium voltage without the need for local DC fields.
We present the results of an extensive experimental campaign on our torsion pendulum, which tested the performance of a prototype charge management in a setup that reproduces the LISA GRS accurately. We will also present a simple photoemission model that successfully reproduces our experimental data and can be used to extract information on the microscopic quantities that affect the discharge properties of the system.
We will discuss possible strategies for keeping the LISA TMs at all times close to neutrality (continuous discharge), which are made possible by pulsed illumination schemes synchronized with voltages applied to the TMs for position sensing and force actuation.
We will finally report on experimental investigations to assess the performance and the additional force noise related to the continuous discharge strategy.
Authors: Davide Dal Bosco, Rita Dolesi, William Joseph Weber, Antonella Cavalleri, Giuliana Russano, Fulvio De Persio, Massimo Bassan, Giuseppe Masciantonio, Francisco Rivas Garcia
Presenter: Davide Dal Bosco
Cosmic rays, solar energetic particles, and other forms of radiation tend to accumulate electric charges on isolated objects placed in the space environment. This is a well-established issue that, if not addressed, could spoil the performance of future space-borne gravitational wave detectors, such as LISA.
The precursor mission LISA Pathfinder has proven that a contactless charge management system that employs UV radiation produced by Hg-lamps can successfully control the test mass charge. LISA Pathfinder applied a periodic discharge strategy: once the TM charge exceeded a threshold (~every two weeks), it was illuminated to bring its charge within the allowed range.
In LISA, it is envisioned to use UV-LEDs as light sources for the charge management system, which brings several advantages with respect to Hg-lamps in terms of reliability, robustness, weight-saving, and, more importantly, flexibility in the illumination scheme.
Indeed, the illumination with UV-LEDs can be synchronized with the TM injection voltages and this allows to reach bipolar discharge and precisely control the test mass equilibrium voltage without the need for local DC fields.
We present the results of an extensive experimental campaign on our torsion pendulum, which tested the performance of a prototype charge management in a setup that reproduces the LISA GRS accurately. We will also present a simple photoemission model that successfully reproduces our experimental data and can be used to extract information on the microscopic quantities that affect the discharge properties of the system.
We will discuss possible strategies for keeping the LISA TMs at all times close to neutrality (continuous discharge), which are made possible by pulsed illumination schemes synchronized with voltages applied to the TMs for position sensing and force actuation.
We will finally report on experimental investigations to assess the performance and the additional force noise related to the continuous discharge strategy.
Authors: Davide Dal Bosco, Rita Dolesi, William Joseph Weber, Antonella Cavalleri, Giuliana Russano, Fulvio De Persio, Massimo Bassan, Giuseppe Masciantonio, Francisco Rivas Garcia
Presenter: Davide Dal Bosco
