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This contribution describes the Trigger board of the High-Energy Particle Detector, which will be placed onboard the second China Seismo-Electromagnetic Satellite for CSES-Limadou mission. This mission will monitor variations in ionospheric parameters that are supposed to be related to earthquakes. The first satellite is already in orbit and the second one will be launched in 2023. The HEPD detector will be composed by a tracker made of CMOS sensors (ALPIDE sensors), followed by two segmented planes of plastic scintillators used for trigger signals generation. The actual calorimeter will be composed by twelve planes of plastic scintillator and two segmented planes of an inorganic scintillator called LYSO. The calorimeter is surrounded by five scintillator planes used as a veto system. All the scintillators are coupled with PMTs, whose signals are acquired and digitized by the Trigger board, that also implements the trigger system for the whole apparatus. The ongoing work on the Trigger board consists in the design of both the hardware and the firmware used for the communication with the other boards of the detector, power managing, and the interfacing with the ASIC used for PMTs’ readout. Eventually the Trigger board will be tested to verify its functionalities and its compliance with the HEPD design specifications. Next developments are the integration of the Trigger board with the other systems on the detector and the environmental testing of the whole system.

On 25 August 2018, a G3-class geomagnetic storm reached the Earth’s magnetosphere, causing a transient rearrangement of the charged particle environment around the planet, which was detected by the High-Energy Particle Detector (HEPD) on board the China Seismo-Electromagnetic Satellite (CSES-01). We found that the count rates of electrons in the MeV range were characterized by a depletion during the storm’s main phase and a clear enhancement during the recovery caused by large substorm activity, with the key role played by auroral processes mapped into the outer belt. A post-storm rate increase was localized at L-shells immediately above ∼3 and mostly driven by non-adiabatic local acceleration caused by possible resonant interaction with low-frequency magnetospheric waves.

The radiation belts in the Earth’s magnetosphere pose a hazard to satellite systems and spacecraft missions (both manned and unmanned), heavily affecting payload design and resources, thus resulting in an impact on the overall mission performance and final costs. The NASA AE9/AP9/SPM radiation models for energetic electrons, protons, and plasma provide useful information on the near-Earth environment, but they are still incomplete as to some features and, for some energy ranges, their predictions are not based on a statistically sufficient sample of direct measurements. Therefore, it is of the upmost importance to provide new data and direct measurements to improve their output. In this work, the AP9 model is applied to the China Seismo-Electromagnetic Satellite (CSES-01) orbit to estimate the flux of energetic protons over the South Atlantic Anomaly during a short testing period of one day, 1 January 2021. Moreover, a preliminary comparison with proton data obtained from the High-Energy Particle Detector (HEPD) on board CSES-01 is carried out. This estimation will serve as the starting ground for a forthcoming complete data analysis, enabling extensive testing and validation of current theoretical and empirical models.

CSES (China Seismo-Electromagnetic Satellite) is a mission developed by CNSA (Chinese National Space Administration) and ASI (Italian Space Agency), to investigate the near-Earth electromagnetic, plasma and particle environment, for studying the seismo-associated disturbances in the ionosphere-magnetosphere transition zone. The anthropogenic and electromagnetic noise, as well as the natural non-seismic electromagnetic emissions is mainly due to tropospheric activity. In particular, the mission aims to confirming the existence of possible temporal correlations between the occurrence of earthquakes for medium and strong magnitude and the observation in space of electromagnetic perturbations, plasma variations and precipitation of bursts with high-energy charged particles from the inner Van Allen belt. In this framework, the high energy particle detector (HEPD) of the CSES mission has been developed by the Italian LIMADOU Collaboration. HEPD is an advanced detector based on a tower of scintillators and a silicon tracker that provides good energy and angular resolution and a wide angular acceptance, for electrons of 3-100 MeV, protons of 30-200 MeV and light nuclei up to the oxygen. CSES satellite has been launched on February 2nd, 2018 from the Jiuquan Satellite Launch Center (China). © 2018, Science China Press and Springer-Verlag GmbH Germany, part of Springer Nature.

The Sileye3/Alteino experiment is devoted to the investigation of the light flash phenomenon and particle composition of the cosmic ray spectrum inside the ISS. The particle detector is a silicon telescope consisting of eight planes, each divided into 32 strips. Data acquisition was initiated in 2002 in the Russian Pirs module. The data on nuclei from C to Fe in the energy range above about 60 MeV/n presented here were taken as part of the ESA Altcriss project [ 1] from late 2005 through 2007. Here we report on LET, from different locations and orientations, in both the Pirs and Zvezda modules. Taking solar modulation into account the results are in agreement with ALTEA measurements from USLab [ 2]. To convert the energy deposition in Si to the equivalent in water, the logarithmic relation between LET in Si and water adopted from [ 3]. In Fig. ​Fig.1,1, the LET spectra in water for Alteino and ALTEA are compared with DOSTEL spectrum from 2001 [ 4], and we see a good overall agreement. We are currently in the process of preparing a detailed paper on the dose and dose equivalent rates in different places inside the Zvezda and Pirs modules and a novel analysis of the contribution to the different doses as a function of strip hit multiplicity. Fig. 1. LET spectra in water from Alteino (red triangle), ALTEA (black diamond) [ 2], DOSTEL 2001 (solid line) [ 4]. Keywords: LET, ISS, Sileye3, Alteino, Altcriss, ALTEA ACKNOWLEDGEMENTS We would like to extend our gratitude to ESA, the Italian Ministry of Foreign Affairs, Riken, ACPP, the Russian Space Agency, ASI, and to INFN for all support building the detector, launching it to the Space Station and for data handling. We thank all colleagues and friends at MARS center, Napoli, for the fundamental support and help for the whole duration of the mission.

The High-Energy Particle Detector (HEPD) is one of the payloads of the CSES space mission, built by the Italian “Limadou” collaboration. It will study the temporal stability of the inner Van Allen radiation belts, the precipitation of trapped particles in the atmosphere and the low energy component of the cosmic rays (5 - 100 MeV for electrons and 15 - 300 MeV for protons). Results of the test beams held at the Beam Test Facility of the INFN National Laboratory of Frascati, for electrons, and at the Proton Cyclotron of Trento, for protons, will be presented. The performance of the apparatus both on the energy reconstruction and in the lepton/hadron separation will be shown.