Uploaded July 2022 | Updated September 2026, 1 hour ago
Cosmic rays will cause an electric charge build-up in LISA’s gravitational reference sensors over time. This charge results in electrostatic forces that interfere with gravitational wave observations. To limit this effect, the test masses will need to be periodically or continuously discharged to neutralize any charge build-up that occurs. Discharging of the test masses is done by photoemission under illumination with ultraviolet light with a wavelength of around 250 nm. While LISA Pathfinder utilized the emission of mercury lamps, ultraviolet LEDs (UV LEDs) offer many advantages over mercury lamps and are being considered as a future light source for LISA. These advantages include a lower mass, higher efficiency, and the ability to operate the devices in a pulsed manner, leading to a dynamic range of ~107. However, since UV LEDs are not a flight-proven technology, they must be evaluated for longevity at the expected operating conditions they may be used in during flight.
This presentation will address the ongoing efforts at the University of Florida to space-qualify these UV LEDs for use in the Charge Management System (CMS) for LISA. The results of the first 18 months of a two-year planned lifetime test will be presented, including up-to-date degradation data of 96 UV LEDs. We will also show the latest model development work being performed to predict the long-term performance of these devices as well as radiation testing results of the UV LEDs and photodiodes that the CMS will use.
Authors: Benjamin Letson, Simon Barke, Taiwo Olatunde, Samantha Kenyon, Myles Clark, Timothy Sumner, Guido Mueller, Fan Ren, Stephen Pearton, Peter Wass, John Conklin
Presenter: Benjamin Letson
Cosmic rays will cause an electric charge build-up in LISA’s gravitational reference sensors over time. This charge results in electrostatic forces that interfere with gravitational wave observations. To limit this effect, the test masses will need to be periodically or continuously discharged to neutralize any charge build-up that occurs. Discharging of the test masses is done by photoemission under illumination with ultraviolet light with a wavelength of around 250 nm. While LISA Pathfinder utilized the emission of mercury lamps, ultraviolet LEDs (UV LEDs) offer many advantages over mercury lamps and are being considered as a future light source for LISA. These advantages include a lower mass, higher efficiency, and the ability to operate the devices in a pulsed manner, leading to a dynamic range of ~107. However, since UV LEDs are not a flight-proven technology, they must be evaluated for longevity at the expected operating conditions they may be used in during flight.
This presentation will address the ongoing efforts at the University of Florida to space-qualify these UV LEDs for use in the Charge Management System (CMS) for LISA. The results of the first 18 months of a two-year planned lifetime test will be presented, including up-to-date degradation data of 96 UV LEDs. We will also show the latest model development work being performed to predict the long-term performance of these devices as well as radiation testing results of the UV LEDs and photodiodes that the CMS will use.
Authors: Benjamin Letson, Simon Barke, Taiwo Olatunde, Samantha Kenyon, Myles Clark, Timothy Sumner, Guido Mueller, Fan Ren, Stephen Pearton, Peter Wass, John Conklin
Presenter: Benjamin Letson
