Solar Intensity X-ray and particle Spectrometer (SIXS)

X-ray and γ -ray spectroscopy using a 2 × 2 GaAs p+-i-nLioliou1, Barnett2 2021Nuclear Instruments and Methods in Physics Research Section A: 60101View full textAdd to dashboardCite

“…The average electron-hole pair creation energy, ω, and Fano factor, F, of GaAs, 4.184 eV at 5.9 keV [15] and 0.12 [18], respectively, results in charge carrier creation statistics and Fano limited spectroscopic resolutions similar to Si (ω = 3.62 eV [19], F = 0.118 [20]), and slightly better than those of Cd1-xZnxTe (ω = 4.43 eV for x = 0 and ω = 4.6 eV for x = 0.1 [17], 0.084 ≤ F ≤ 0.24 [11]). Furthermore, the high radiation resistance of GaAs [21] makes it a suitable choice in space environments with intense radiation. However, whilst GaAs has greater linear X-ray absorption coefficients than Si (e.g.…”

Investigating Mercury’s Environment with the Two-Spacecraft BepiColombo Mission

“…Particle-induced X-ray emission (PIXE) is of especially strong interest for the Bepi-Colombo mission to characterise the structure and composition of Mercury's surface (Huovelin et al 2010). Proton cross-sections for PIXE peak at proton energies of 1.5-15 MeV for lines of the most interesting elements (Huovelin et al 2010). The PIXE production for those lines from typical proton spectra (rapidly decreasing at high energies) observed during large SEP events peaks at energies from below 1 MeV to about 5 MeV (Harjunmaa 2004).…”

Solar Intensity X-Ray and Particle Spectrometer SIXS: Instrument Design and First Results

“…The resources of the SIXS experiment only allow one particle measurement technique to be employed, rendering the measurement of the entire energy range for electrons and protons a very difficult, if not impossible task. The trade-off has been made in favour of protons and high-energy electrons, because it is possible to use the MIXS X-ray measurements of the bremsstrahlung continuum caused by multi-keV electrons hitting the surface of Mercury to estimate the electron intensities below a few tens of keV (Huovelin et al 2010). A further reason in favour of optimising the measurements for the protons and high-energy electrons is that even if it would be possible to measure the low-energy electron fluxes locally, there would be a less direct connection between the measured fluxes at MPO and those hitting the planetary surface below the spacecraft.…”

“…The first comprehensive description of the SIXS instrument, as well as its scientific and technological background and heritage and science plan is published in Huovelin et al (2010), and the present paper is an updated description, including the final design, performance and first results after the launch of BepiColombo.…”