The ESA-JAXA BepiColombo mission to Mercury will provide simultaneous
measurements from two spacecraft, offering an unprecedented opportunity to investigate
magnetospheric and exospheric particle ...dynamics at Mercury as well as their interactions
with solar wind, solar radiation, and interplanetary dust. The particle instrument suite SERENA
(Search for Exospheric Refilling and Emitted Natural Abundances) is flying in space
on-board the BepiColombo Mercury Planetary Orbiter (MPO) and is the only instrument for
ion and neutral particle detection aboard the MPO. It comprises four independent sensors:
ELENA for neutral particle flow detection, Strofio for neutral gas detection, PICAM for
planetary ions observations, and MIPA, mostly for solar wind ion measurements. SERENA
is managed by a System Control Unit located inside the ELENA box. In the present paper
the scientific goals of this suite are described, and then the four units are detailed, as well
as their major features and calibration results. Finally, the SERENA operational activities
are shown during the orbital path around Mercury, with also some reference to the activities
planned during the long cruise phase.
Abstract
High-energy, long gamma-ray bursts (GRBs) can be generated by the core collapse of massive stars at the end of their lives. When they happen in the close-by universe they can be ...exceptionally bright, as seen from the Earth in the case of the recent, giant, long-lasting GRB221009A. GRB221009A was produced by a collapsing star with a redshift of 0.152: this event was observed by many gamma-ray space experiments, which also detected an extraordinary long gamma-ray afterglow. The exceptionally large fluence of the prompt emission of about 0.013 erg cm
−2
illuminated a large geographical region centered on India and including Europe and Asia. We report in this paper the observation of sudden electron flux changes correlated with GRB221009A and measured by the HEPP-L charged particle detector on board the China Seismo-Electromagnetic Satellite, which was orbiting over Europe at the time of the GRB event. The time structure of the observed electron flux closely matches the very distinctive time dependence of the photon flux associated with the main part of the emission at around 13:20 UTC on 2022 October 9. To test the origin of these signals, we set up a simplified simulation of one HEPP-L subdetector: the results of this analysis suggest that the signals observed are mostly due to electrons created within the aluminum collimator surrounding the silicon detector, providing real-time monitoring of the very intense photon fluxes. We discuss the implications of this observation for existing and forthcoming particle detectors on low Earth orbits.
Abstract
In this paper we report the detection of five strong gamma-ray bursts (GRBs) by the High-Energy Particle Detector (HEPD-01) mounted on board the China Seismo-Electromagnetic Satellite, ...operational since 2018 on a Sun-synchronous polar orbit at a ∼507 km altitude and 97° inclination. HEPD-01 was designed to detect high-energy electrons in the energy range 3–100 MeV, protons in the range 30–300 MeV, and light nuclei in the range 30–300 MeV n
−1
. Nonetheless, Monte Carlo simulations have shown HEPD-01 is sensitive to gamma-ray photons in the energy range 300 keV–50 MeV, even if with a moderate effective area above ∼5 MeV. A dedicated time correlation analysis between GRBs reported in literature and signals from a set of HEPD-01 trigger configuration masks has confirmed the anticipated detector sensitivity to high-energy photons. A comparison between the simultaneous time profiles of HEPD-01 electron fluxes and photons from GRB190114C, GRB190305A, GRB190928A, GRB200826B, and GRB211211A has shown a remarkable similarity, in spite of the different energy ranges. The high-energy response, with peak sensitivity at about 2 MeV, and moderate effective area of the detector in the actual flight configuration explain why these five GRBs, characterized by a fluence above ∼3 × 10
−5
erg cm
−2
in the energy interval 300 keV–50 MeV, have been detected.
The Radio Science Experiments of the BepiColombo mission will enable substantial improvement of the knowledge of Mercury's orbit and rotation, and the relativistic dynamics in the solar system. A ...fundamental support to the spacecraft tracking data will be given by the Italian Spring Accelerometer (ISA). This is a three-axis accelerometer devoted to the measurement of the non-gravitational perturbations acting on the Mercury Planetary Orbiter (MPO), whose knowledge is important in order to fully exploit the quality of the tracking data. The intrinsic noise level of the instrument that will be onboard MPO,
10
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/
Hz
in the
3
×
10
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5
to
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1
Hz
frequency range, guarantees the fulfilment of the RSE requirements. The main scientific and technological features of the instrument are discussed, together with its current error budget, experimental activities and foreseen calibration strategies.
Due to be launched in late 2021, the Imaging X-ray Polarimetry Explorer (IXPE) is a NASA Small Explorer mission designed to perform polarization measurements in the 2–8 keV band, complemented with ...imaging, spectroscopy and timing capabilities. At the heart of the focal plane is a set of three polarization-sensitive Gas Pixel Detectors (GPD), each based on a custom ASIC acting as a charge-collecting anode.
In this paper we shall review the design, manufacturing, and test of the IXPE focal-plane detectors, with particular emphasis on the connection between the science drivers, the performance metrics and the operational aspects. We shall present a thorough characterization of the GPDs in terms of effective noise, trigger efficiency, dead time, uniformity of response, and spectral and polarimetric performance. In addition, we shall discuss in detail a number of instrumental effects that are relevant for high-level science analysis—particularly as far as the response to unpolarized radiation and the stability in time are concerned.
The analyser of space plasma and energetic atoms (ASPERA-3) neutral particle imager (NPI) on board Mars Express (MEX) is devoted to energetic neutral atom (ENA) detection within the Martian ...environment. These ENAs originate from the interaction between the energetic ions flowing inside the Martian environment and the exospheric neutral gas, thus providing crucial information about the dynamics of this interaction. NPI records the instantaneous angular distribution of the energy-integrated ENA signal. In order to identify recurrent ENA signals in the Martian environment, we have performed a statistical analysis of the NPI data. Count rates have been averaged using different methods in order to be able to discriminate signals coming from the planet, from a selected direction, or from specific planetographic regions at the planetary surface. Possible recurrent ENA signals (about 5×10
6
(cm
2
sr
s)
−1) are found coming from the terminator direction and above the atmosphere toward nightside when the spacecraft was inside the planetary shadow, mainly close to the shadow edge. Some significant signal was found from the anti-Mars directions in 2005. No statistically significant signal related to pick-up ions from the atmosphere or related to magnetic anomalies above the sensor intrinsic error (estimated as 3×10
6
(cm
2
sr
s)
−1) was observed. Our analysis shows that particular attention should be given to the use of NPI data when performing statistical studies; in fact, the sensor has some intrinsic limitations due to inadequate UV suppression, difficulties in sector inter-calibrations, and variations in the sector response versus time.
The ALMA telescope is one of the largest on-ground astronomical projects in the world. It has been producing great scientific results since the beginning of operations in 2011. Of all the originally ...planned bands, band 2 (67-90 GHz) is the last band to be implemented into the array. Recent technological progress has open the possibility to combine bands 2 and 3 (84-116 GHz) into a single wideband receiver. This paper describes the first efforts to design wideband optics which cover both bands, from 67 to 116 GHz, using a profiled corrugated horn and a modified Fresnel lens. First measurements were performed at ESO in Dec15-Jan16 and showed good agreement with simulations.
Due to be launched in late 2021, the Imaging X-Ray Polarimetry Explorer (IXPE) is a NASA Small Explorer mission designed to perform polarization measurements in the 2-8 keV band, complemented with ...imaging, spectroscopy and timing capabilities. At the heart of the focal plane is a set of three polarization-sensitive Gas Pixel Detectors (GPD), each based on a custom ASIC acting as a charge-collecting anode. In this paper we shall review the design, manufacturing, and test of the IXPE focal-plane detectors, with particular emphasis on the connection between the science drivers, the performance metrics and the operational aspects. We shall present a thorough characterization of the GPDs in terms of effective noise, trigger efficiency, dead time, uniformity of response, and spectral and polarimetric performance. In addition, we shall discuss in detail a number of instrumental effects that are relevant for high-level science analysis -- particularly as far as the response to unpolarized radiation and the stability in time are concerned.
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