
@article{BARTOCCI2025170756,
title = {TROPix: A parametric tool reproducing the output of the HEPD-02 pixel detector},
journal = {Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment},
volume = {1080},
pages = {170756},
year = {2025},
issn = {0168-9002},
doi = {https://doi.org/10.1016/j.nima.2025.170756},
url = {https://www.sciencedirect.com/science/article/pii/S0168900225005571},
author = {{Bartocci S. \textit{et al.}}},
keywords = {Simulation, Pixel detectors, MAPS},
abstract = {This paper introduces TROPix, a parametric simulation tool designed to reproduce the output of silicon pixel detectors. Developed for the Direction Detector of the HEPD-02 detector on the second China Seismo-Electromagnetic Satellite (CSES-02), TROPix utilizes the GEANT4 toolkit for energy deposition and a parametric approach for charge generation and diffusion. The simulation process incorporates thermal noise and digitization, with all parameters fine-tuned using experimental beam-test data. Although TROPix is tuned for HEPD-02 data, it can also be adapted for use with other detectors employing pixel sensors, providing a versatile and computationally efficient solution for numerous applications. Results for Monolithic Active Pixel Sensors (MAPS) based on ALTAI chips are presented, highlighting TROPix’s ability to replicate the property of pixel clusters, defined as the number of pixels fired by the particle passage. These characteristics comprehend the dependencies on charged particle deposited energy and incident angle, as well as the typical shapes of clusters. Validation using beam test data acquired with ALTAI sensors demonstrates that TROPix reproduces the cluster size dependence on deposited energy, with agreement within 20%. For cluster shape occurrences, the simulated results align with the data within 25% of the total uncertainty.}
}


@article{Shen,
author={{Shen, X. \textit{et al.}}},
title={The state-of-the-art of the China Seismo-Electromagnetic Satellite mission},
journal={Science China Technological Sciences},
year={2018},
month={May},
day={01},
volume={61},
number={5},
pages={634-642},
abstract={The China Seismo-Electromagnetic Satellite (CSES) mission was proposed in 2003 and approved in 2013 after ten years' scientific and engineering demonstrations. To meet the requirement of scientific objectives, the satellite is designed to be in a sunsynchronous orbit with an altitude of 507 km and descending node time of 14:00 LT. The CSES satellite carries 8 instruments, including search-coil magnetometer (SCM), electric field detector (EFD), high precision magnetometer (HPM), GNSS occultation receiver (GOR), plasma analyzer package (PAP), langmuir probe (LAP), high energetic particle package (HEPP) and detector (HEPD), and tri-band beacon (TBB), among which HEPD is provided by Italian Space Agency. The CSES satellite was launched successfully on February 2, 2018, and is planned to operate for 5 years. The CSES mission is the first satellite in China to measure geophysical fields, which will have a lot of application prospects in the study of seismology, geophysics, space sciences, and so on.},
issn={1869-1900},
doi={10.1007/s11431-018-9242-0},
url={https://doi.org/10.1007/s11431-018-9242-0}
}

@inproceedings{DeSantis:2021WO,
  author = "De Santis, Cristian  and  Ricciarini, Sergio",
  title = "{The High Energy Particle Detector (HEPD-02) for the second China Seismo-Electromagnetic Satellite (CSES-02)}",
  doi = "10.22323/1.395.0058",
  booktitle = "Proceedings of 37th International Cosmic Ray Conference {\textemdash} PoS(ICRC2021)",
  year = 2021,
  volume = "395",
  pages = "058"
}

@article{Palma_2024,
doi = {10.3847/1538-4357/ad06ae},
url = {https://dx.doi.org/10.3847/1538-4357/ad06ae},
year = {2023},
month = {dec},
publisher = {The American Astronomical Society},
volume = {960},
number = {1},
pages = {21},
author = {{Palma, F. \textit{et al.}}},
title = {Gamma-Ray Burst Observations by the High-Energy Particle Detector on board the China Seismo-Electromagnetic Satellite between 2019 and 2021},
journal = {The Astrophysical Journal},
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.}
}

@article{Battiston_2023,
doi = {10.3847/2041-8213/acc247},
url = {https://dx.doi.org/10.3847/2041-8213/acc247},
year = {2023},
month = {mar},
publisher = {The American Astronomical Society},
volume = {946},
number = {1},
pages = {L29},
author = {{Battiston, R. \textit{et al.}}},
title = {Observation of Anomalous Electron Fluxes Induced by GRB221009A on CSES-01 Low-energy Charged Particle Detector},
journal = {The Astrophysical Journal Letters},
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.}
}

@article{Bartocci_2024,
doi = {10.3847/1538-4357/ad822c},
url = {https://dx.doi.org/10.3847/1538-4357/ad822c},
year = {2024},
month = {nov},
publisher = {The American Astronomical Society},
volume = {976},
number = {2},
pages = {239},
author = {{Bartocci, S. \textit{et al.}}},
title = {The Catalogue of Gamma-Ray Burst Observations by HEPD-01 in the 0.3–50 MeV Energy Range},
journal = {The Astrophysical Journal},
abstract = {The High-Energy Particle Detector (HEPD-01) on board the China Seismo-Electromagnetic Satellite, located on a Sun-synchronous orbit at 500 km of altitude with an inclination of 97°, features a dedicated logic counting low-energy event rates, which proved sensitive to intense Gamma-Ray Burst (GRB). The present work reports a comprehensive analysis of signals induced by GRBs in the event-rate data collected between 2018 August and 2022 June. After accurately modeling the background rate as observed in different passages of the satellite over the same geographical area, we detected significant deviations to be compared with observations of GRB candidates from other observatories. The analysis revealed 12 statistically significant excesses, that have been associated with GRB 181222B, GRB 190114C, GRB 190129B, GRB 190305A, GRB 190928A, GRB 200412B, GRB 200422A, GRB 200826B, GRB 201009A, GRB 210702A, GRB 211211A, and GRB 220624A. We report light curves for 0.3–50 MeV photons, comparing them with findings from other space telescopes. The catalog of observations is published, complete of GRB observation time, duration, integrated counts, and fluence.}
}

@article{Martucci_2023,
doi = {10.3847/2041-8213/acbea7},
url = {https://dx.doi.org/10.3847/2041-8213/acbea7},
year = {2023},
month = {mar},
publisher = {The American Astronomical Society},
volume = {945},
number = {2},
pages = {L39},
author = {{Martucci, M. \textit{et al.}}},
journal = {The Astrophysical Journal Letters},
abstract = {Time-dependent energy spectra of galactic cosmic rays (GCRs) carry crucial information regarding their origin and propagation throughout the interstellar environment. When observed at the Earth, after traversing the interplanetary medium, such spectra are heavily affected by the solar wind and the embedded solar magnetic field permeating the inner sectors of the heliosphere. The activity of the Sun changes significantly over an 11 yr solar cycle—and so does the effect on cosmic particles; this translates into a phenomenon called solar modulation. Moreover, GCR spectra during different epochs of solar activity provide invaluable information for a complete understanding of the plethora of mechanisms taking place in various layers of the Sun’s atmosphere and how they evolve over time. The High-Energy Particle Detector (HEPD-01) has been continuously collecting data since 2018 August, during the quiet phase between solar cycles 24 and 25; the activity of the Sun is slowly but steadily rising and is expected to peak around 2025/2026. In this paper, we present the first spectra for ∼50–250 MeV galactic protons measured by the HEPD-01 instrument—placed on board the CSES-01 satellite—from 2018 August to 2022 March over a one-Carrington-rotation time basis. Such data are compared to the ones from other spaceborne experiments, present (e.g., EPHIN, Parker Solar Probe) and past (PAMELA), and to a state-of-the-art three-dimensional model describing the GCRs propagation through the heliosphere.}
}

@article{Bartocci_2025,
doi = {10.1088/1748-0221/20/06/P06005},
url = {https://dx.doi.org/10.1088/1748-0221/20/06/P06005},
year = {2025},
month = {jun},
publisher = {IOP Publishing},
volume = {20},
number = {06},
pages = {P06005},
author = {{Bartocci, S. \textit{et al.}}},
title = {Development of the power supply of HEPD-02 instrument on board CSES-02 satellite},
journal = {Journal of Instrumentation},
abstract = {The High Energy Particle Detector HEPD-02 is primarily devoted to observe fluxes of cosmic-ray electrons, protons and light nuclei, with kinetic energies in the range from less than 10 MeV to few hundreds MeV, either incoming or trapped in the terrestrial magnetosphere. HEPD-02 will be hosted on board the China Seismo-Electromagnetic Satellite CSES-02. The CSES mission, coordinated by China National Space Administration (CNSA) and Italian Space Agency (ASI), aims at developing a series of satellites for the study of the near-Earth environment, by means of electromagnetic, ionospheric, magnetospheric and cosmic-ray observations. HEPD-02 is a state-of-the-art instrument for measurement of energy and arrival direction and for identification of incoming cosmic particles; it is formed by a tower of superimposed plastic and crystal scintillator layers, read-out by photo-multiplier tubes (PMTs), with a direction detector composed of monolithic active pixel sensors. This paper describes the design, structure and operation of the power supply component of HEPD-02, which comprises a low-voltage unit for power distribution to other sub-systems and a high-voltage unit for generation of PMT bias. The HEPD-02 power supply features specific and optimized design solutions matching the demanding requirements for employment on board the CSES-02 satellite: it is conceived to guarantee at least 6 years of continuous operation, delivering stable voltages with low susceptibility to electromagnetic interference, in a harsh environment (characterized by relatively intense ionizing radiation, wide temperature excursions, absence of heat dissipation by air convection), after sustaining strong mechanical stresses at launch, at the same time complying with strict limits in mass, dimensions and available power.}
}