A charge control method for space-mission inertial sensor using differential UV LED emission

Yang, Fangchao; Bai, Yanzheng; Hong, Wei; Sumner, T. J.; Zhou, Zebing

doi:10.1063/5.0013232

Cited by 13 publications

(18 citation statements)

References 31 publications

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“…We refer to the techniques as the fast photoelectron (FPE) and slow photoelectron (SPE) methods and describe them in detail below. The FPE method independently validates the work described by Yang et al [28] for a generic configuration and expands on it by explicitly showing the dependence of the system parameters on vacuum preparation and temperature. The SPE approach is by design insensitive to system parameters for an equilibrium TM potential |V(TM)| < 10 mV.…”

Section: Introductionsupporting

confidence: 53%

Two approaches for the passive charge management of contactless test masses

Wang¹,

Saraf²,

Lipa³

et al. 2022

Class. Quantum Grav.

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Free floating Test Masses (TM) of inertial reference instruments accumulate charge mainly through the triboelectric effect during separation from their housings and, if in the space environment, from cosmic radiation. These charges will degrade the accuracy of high sensitivity accelerometers and drag-free sensors. We demonstrate in ground testing two passive bipolar charge management systems using photoelectrons emitted from gold coated surfaces under illumination by Ultraviolet Light Emitting Diodes (UV LEDs) with 255 nm, 275 nm, and 295 nm central wavelengths. The first method uses fast photoelectrons, generated by two 255 nm UV-LEDs with adjustable-intensity (through fine-tuning of their excitation currents) and illuminating the TM and its housing respectively. A second technique uses slow photoelectrons generated by one UV LED, of either 275 nm or 295 nm, directed at the TM. Fast and slow electrons are defined as having kinetic energies after photoemission above and below 〖eV〗_TM^max, where V_TM^max is the maximum allowable potential required for normal operation of the TM. In its optimized configurations and following an exposure of < 30 sec to UV, the fast-photoelectron control system converges to zero TM potential from  1 V with a drift of  1.5 mV/day. The slow-photoelectron system requires about 5 minutes to converge to zero TM potential from 100 mV, with a similar drift of  2.0 mV/day. For reference, V_TM^max≅80mV for the LISA and LISA pathfinder sensors. While the two-source UV fast photoelectron method is a modification of the LISA Pathfinder approach, the slow photoelectron method is a new passive charge management technique. These two passive techniques were developed for instruments without sensing and activation systems. For instruments with electric fields surrounding the TM and more complex geometries additional adaptations are required.

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Section: Introductionsupporting

confidence: 53%

Two approaches for the passive charge management of contactless test masses

Wang¹,

Saraf²,

Lipa³

et al. 2022

Class. Quantum Grav.

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“…In both missions, low-pressure mercury vapor lamps were used to generate UV light for discharge at a wavelength of 254 nm. Compared to mercury lamps, UV LEDs offer advantages in terms of size, electrical power efficiency, light weight, and low power consumption, and have been tested and identified as a new light source for the CMS [24][25][26][27][28][29].…”

Section: Charge Management System (Cms)mentioning

confidence: 99%

“…Conversely, a negative TM discharging rate is obtained. The number of photoelectrons (marked in red) that can migrate from surface i to surface j per unit time can be simply written as [28,47] The UV light (purple) illuminates the EH surface and releases photoelectrons either from the EH surface (marked in red) or from the TM surface (marked in yellow). The TM potential is positively charged at the beginning, and the EH is connected to the ground.…”

Section: Model Derivationmentioning

confidence: 99%

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Adaptive charge control for the space inertial sensor

Yang¹,

Hong²,

Li³

et al. 2023

Class. Quantum Grav.

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Inertial sensors are key components of gravitational wave observations and Earth geodesy missions. An inertial sensor includes an isolated free-floating test mass (TM) surrounded by capacitive electrodes and a housing frame (EH) to perform the relative-position measurement and control the TM in six degrees of freedom. Owing to galactic cosmic rays (GCRs) and solar energetic particles (SEPs), many additional accelerations are introduced through the Coulomb interaction between charged TMs and their surrounding conducting surfaces. Thus, the TM charge control is critical in space-based missions. A contact-free and ultraviolet (UV) light-based charge management system (CMS) was developed to reduce charge-induced noises acting on the TMs and minimize force disturbances that can perturb measurements or interrupt science tasks. However, the operating environment for space charge control is full of uncertainties and disturbances. Physical parameters in the discharging process are rarely measured and will vary owing to changes in solar activity, temperature, and so on. The unpredictability and variability of these parameters affects the CMS performance in long-term space missions and must be evaluated or eliminated. This paper presents a simplified physical model for the discharge process based on electron exchange between the TM and the opposing EH. Subsequently, a model reference adaptive control (MRAC) is proposed for the CMS with parametric uncertainties to maintain the TM charge below a certain level and improve its robustness. The simulation results show that the MRAC can automatically adjust control parameters to eliminate the effect of the variability of the aforementioned physical parameters, and the control precision can reach 0.1 mV under uncertainties, which is superior to that of a classic proportional-integral-derivative controller. This study demonstrated the effects of adaptive charge control and its potential for actual applications.

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“…(3) Neutralization by electron and ion beams [23]. (4) Discharge by UV radiation [24]. Discharge via electrical connection is the simplest method.…”

Section: Introductionmentioning

confidence: 99%

Study on the Method of Charge Accumulation Suppression of Electrostatic Suspended Accelerometer

Dai

Wang

et al. 2022

Sensors

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Electrostatic suspended accelerometers (ESAs) are widely used in high accuracy acceleration measurement. However, there exist accumulated charges on the isolated mass which damage the accuracy and the stability of ESAs. In this paper, we propose to apply actuation voltage with a combined waveform to suppress the acceleration noise due to deposited charge. A model of the electrostatic force on the mass is established and the deviation voltage is found to be the dominant source of charge noise. Based on the analysis of disturbance electrostatic force under DC and AC signals, actuation combined with DC and AC voltage is designed and the disturbance force due to charge can be suppressed through adjustment towards the duty cycle of different compositions. Simulations and experiments are carried out and the results indicate that the disturbance due to charge can be suppressed up to 40%, which validates the efficiency of the scheme.

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A charge control method for space-mission inertial sensor using differential UV LED emission

Cited by 13 publications

References 31 publications

Two approaches for the passive charge management of contactless test masses

Two approaches for the passive charge management of contactless test masses

Adaptive charge control for the space inertial sensor

Study on the Method of Charge Accumulation Suppression of Electrostatic Suspended Accelerometer

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