Low-energy electron emission at the separation of gold-platinum surfaces induced by galactic cosmic rays on board LISA Pathfinder

Villani, Mattia; Benella, Simone; Fabi, Michele; Grimani, C.

doi:10.1016/j.apsusc.2020.145734

Cited by 15 publications

(29 citation statements)

References 16 publications

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“…A similar approach was considered for the LISA Pathfinder mission orbiting around the first Lagrange point during the years 2016-2017 (Armano et al 2016(Armano et al , 2018b. It was shown in Villani et al (2020) that the integral proton flux predictions carried out with the G&A model for LISA Pathfinder differ by less than 10% from the Alpha Magnetic Spectrometer (AMS-02) experiment data (AMS Collaboration 2002; Aguilar et al 2018) gathered on the Space Station during the Bartels Rotation 2491 (Grimani et al 2019). For the present work, it is also possible to benefit of the proton and helium differential flux measurements of the EPD/HET instrument flying on board Solar Orbiter and gathering data in the energy range below 100 MeV in order to further reduce the uncertainty on the GCR flux predictions, while we await the publication of the AMS-02 data for the years after 2017, up to TeV energies.…”

Section: Galactic Cosmic-ray Energy Spectra In the Summer 2020 For Solar Orbitermentioning

confidence: 92%

Cosmic-ray flux predictions and observations for and with Metis on board Solar Orbiter

Grimani

Andretta

Chioetto

et al. 2021

A&A

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Context. The Metis coronagraph is one of the remote sensing instruments hosted on board the ESA/NASA Solar Orbiter mission. Metis is devoted to carry out the first simultaneous imaging of the solar corona in both visible light (VL) and ultraviolet (UV). High-energy particles can penetrate spacecraft materials and may limit the performance of the on-board instruments. A study of the galactic cosmic-ray (GCR) tracks observed in the first VL images gathered by Metis during the commissioning phase is presented here. A similar analysis is planned for the UV channel. Aims. We aim to formulate a prediction of the GCR flux up to hundreds of GeV for the first part of the Solar Orbiter mission to study the performance of the Metis coronagraph. Methods. The GCR model predictions are compared to observations gathered on board Solar Orbiter by the High-Energy Telescope in the range between 10 MeV and 100 MeV in the summer of 2020 as well as with the previous measurements. Estimated cosmic-ray fluxes above 70 MeV n−1 have been also parameterized and used for Monte Carlo simulations aimed at reproducing the cosmic-ray track observations in the Metis coronagraph VL images. The same parameterizations can also be used to study the performance of other detectors. Results. By comparing observations of cosmic-ray tracks in the Metis VL images with FLUKA Monte Carlo simulations of cosmic-ray interactions in the VL detector, we find that cosmic rays fire only a fraction, on the order of 10−4, of the whole image pixel sample. We also find that the overall efficiency for cosmic-ray identification in the Metis VL images is approximately equal to the contribution of Z ≥ 2 GCR particles. A similar study will be carried out during the whole of the Solar Orbiter’s mission duration for the purposes of instrument diagnostics and to verify whether the Metis data and Monte Carlo simulations would allow for a long-term monitoring of the GCR proton flux.

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Section: Galactic Cosmic-ray Energy Spectra In the Summer 2020 For Solar Orbitermentioning

confidence: 92%

Cosmic-ray flux predictions and observations for and with Metis on board Solar Orbiter

Grimani

Andretta

Chioetto

et al. 2021

A&A

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“…In order to investigate the origin of this mismatch, the GCR spectra adopted in the simulations were first compared to the international space station AMS-02 magnetic spectrometer experiment [18] measurements carried out at the time the mission was in orbit. An agreement was found within ±10 % [17]. According to preliminary results [17] the lack of propagation of low-energy electrons in both FLUKA (< 1 keV) [19,20] and Geant4 Monte Carlo toolkit (< 100 eV) [21] may explain the difference between measured and observed charging noise.…”

Section: Introductionmentioning

confidence: 64%

“…A wrong estimate of the incident GCR fluxes would have led to a mismatch similar for both net and effective charging, moreover after GCR data for the beginning of 2016 [18] were published, we found that our predictions were in agreement within 10% with observations. The possibility that the effective charging mismatch was due to the lack of propagation of electrons below 100 eV was explored in [17] and appeared very promising. In particular, low-energy protons and nuclei traversing the electrodes are observed to produce a large number of electrons and both nuclei and electrons are observed to stop in the TM giving a large contribution to the effective charging.…”

Section: Lisa Pathfinder Pre-launch Test Mass Charging Simulations An...mentioning

confidence: 99%

“…Before the LPF mission launch, the TM charging was studied with Monte Carlo simulations [12,13,14,15]. The net charging prediction associated with GCR only, resulted in good agreement with LPF measurements, while the shot noise was under-estimated by a factor 3-4 [16,17]. In order to investigate the origin of this mismatch, the GCR spectra adopted in the simulations were first compared to the international space station AMS-02 magnetic spectrometer experiment [18] measurements carried out at the time the mission was in orbit.…”

Section: Introductionmentioning

confidence: 99%

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Low-energy electromagnetic processes affecting free-falling test-mass charging for LISA and future space interferometers

Grimani,

Cesarini,

Fabi

et al. 2020

Preprint

Self Cite

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Galactic cosmic rays and solar energetic particles charge gold-platinum, free-falling test masses (TMs) on board interferometers for the detection of gravitational waves in space. The charging process induces spurious forces on the test masses that affect the sensitivity of these instruments mainly below 10 −3 Hz. Geant4 and FLUKA Monte Carlo simulations were carried out to study the TM charging process on board the LISA Pathfinder mission that remained into orbit around the Sun-Earth Lagrange point L1 between 2016 and 2017. While a good agreement was observed between simulations and measurements of the TMs net charging, the shot noise associated with charging fluctuations of both positive and negative particles resulted 3-4 times higher that predicted. The origin of this mismatch was attributed to the propagation of electrons and photons only above 100 eV in the simulations. In this paper, low-energy electromagnetic processes to be included in the future Monte Carlo simulations for LISA and LISA-like space interferometers TM charging are considered. It is found that electrons and photons below 100 eV give a contribution to the effective charging comparable to that of the whole sample of particles above this energy. In particular, for incident protons ionization contributes twice with respect to low energy kinetic emission and electron backscattering. The other processes are found to play a negligible role. For heavy nuclei only sputtering must be considered.

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“…A similar approach was considered for the LISA Pathfinder mission orbiting around the first Lagrange point during the years 2016-2017 (Armano et al 2016(Armano et al , 2018b. It was shown in Villani et al (2020) that the integral proton flux predictions carried out with the G&A model for LISA Pathfinder differ by less than 10% from the Alpha Magnetic Spectrometer (AMS-02) experiment data (AMS Collaboration et al 2002;Aguilar et al 2018) gathered on the Space Station during the Bartels Rotation 2491 (Grimani et al 2019). For the present work, it is also possible to benefit of the proton and helium differential flux measurements of the EPD/HET instrument flying on board Solar Orbiter and gathering data in the energy range below 100 MeV to further reduce the uncertainty on the GCR flux predictions while waiting for the AMS-02 data to be published for the years after 2017 up to TeV energies.…”

Section: Galactic Cosmic-ray Energy Spectra In the Summer 2020 For So...mentioning

confidence: 92%

Cosmic-ray flux predictions and observations for and with Metis on board Solar Orbiter

Grimani,

Andretta,

Chioetto

et al. 2021

Preprint

View full text Add to dashboard Cite

Context. The Metis coronagraph is one of the remote sensing instruments hosted on board the ESA/NASA Solar Orbiter mission. Metis is devoted to carry out the first simultaneous imaging of the solar corona in both visible light (VL) and ultraviolet (UV). Highenergy particles penetrate spacecraft materials and may limit the performance of on-board instruments. A study of galactic cosmic-ray (GCR) tracks observed in the first VL images gathered by Metis during the commissioning phase for a total of 60 seconds of exposure time is presented here. A similar analysis is planned for the UV channel. Aims. A prediction of the GCR flux up to hundreds of GeV is made here for the first part of the Solar Orbiter mission to study the Metis coronagraph performance. Methods. GCR model predictions are compared to observations gathered on board Solar Orbiter by the EPD/HET experiment in the range 10 MeV-100 MeV in the summer 2020 and with previous measurements. Estimated cosmic-ray fluxes above 70 MeV n −1 have been also parameterized and used for Monte Carlo simulations aiming at reproducing the cosmic-ray track observations in the Metis coronagraph VL images. Same parameterizations can also be used to study the performance of other detectors. Results. By comparing observations of cosmic-ray tracks in the Metis VL images with FLUKA Monte Carlo simulations of cosmicray interactions in the VL detector, it is found that cosmic rays fire a fraction of the order of 10 −4 of the whole image pixel sample. Therefore, cosmic rays do not affect sensibly the quality of Metis VL images. It is also found that the overall efficiency for cosmic-ray identification in the Metis VL images is approximately equal to the contribution of Z>2 particles. As a result, the Metis coronagraph may play the role of a proton monitor for long-term GCR variations during the overall mission duration.

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Low-energy electron emission at the separation of gold-platinum surfaces induced by galactic cosmic rays on board LISA Pathfinder

Cited by 15 publications

References 16 publications

Cosmic-ray flux predictions and observations for and with Metis on board Solar Orbiter

Cosmic-ray flux predictions and observations for and with Metis on board Solar Orbiter

Low-energy electromagnetic processes affecting free-falling test-mass charging for LISA and future space interferometers

Cosmic-ray flux predictions and observations for and with Metis on board Solar Orbiter

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