LIMADOU is the name given in honour of the missionary Matteo Ricci (1552-1610) to the experiment of the Chinese Seismo-Electromagnetic Satellite (CSES). The High Energy Particle Detector (HPED), designed and constructed by INFN, is the italian scientific payload on the CSES. The HEPD will study a phenomena reported by instruments on different satellites, which indicates a time correlation between the main earthquake shock and an increase in the electron flux in the inner Van Allen radiation belt. The CSES includes instruments to measure the electric and magnetic fields in order to understand the physics of the lithosphere-atmosphere-ionosphere coupling responsible for the phenomena.

The Science

The instruments on the CSES will monitor electromagnetic and particle-plasma perturbations in the upper atmosphere, the ionosphere and the magnetosphere. The HEPD is designed to measure with good resolution the pitch angle and energy of electrons and protons. The HEPD includes a silicon microstrip tracker, a scintillator-LYSO calorimeter, and five scintillator veto planes, which surround the rectangular volume of the detector.
The CSES will be placed in a sun-synchronous, circular orbit at 600 km with a 98° inclination. The HEPD is positioned on the satellite to point toward the local zenith. The local pitch angle defined by the line-of-sight of the detector varies between 90° at the equator and towards 0° near the poles. The dimensions of the HEPD were chosen to maintain a wide angular acceptance (±45°) throughout the orbit. The electron and proton acceptances are shown in Fig. 3 below. The HEPD will monitor the flux of solar energetic protons (SEP), a complementary measurement required to distinguish flux variations due to seismic and solar activity.
The members of the Trento-TIFPA were at the origin of Limadou experiment, responsible for the detector design. The group is responsible for the Monte Carlo simulation and the event reconstruction, including the detector calibration and performance optimization.
A fundamental issue for the remote detection in near-Earth orbit of seismic phenomena is the spatial correlation between the location the observed particle flux change and the earthquake epicenter. A back-trace analysis program has been developed by the group to establish the spatial correlation of reported time-correlated flux variations. The technique is illustrated in Fig. 2 below, which shows the location of a reported time-correlated event of the NOAA Polar-Orbiting Environmental Satellites (POES), and the trajectory of the back-traced positron in the earth's magnetic field which passes over the time-correlated earthquake epicenter, i.e. the event is time-space-correlated.


• Involved external institutions: Agenzia Spaziale Italiana (ASI), Italy; China National Space Administration (CNSA), China Earthquake Administration (CEA), Lanzhou Institute of Physics (LIP), Space Star Techonology Co., DFH Satellite Co., National Space Science Center (NSSC), Centre for Space Science and Applied Research-­Chinese Academy of Science (CSSAR-CAS), China.
• INFN groups: Full list available at the collaboration website
• Principal Investigator: Roberta Sparvoli, (Università degli studi di Tor Vergata)
• INFN Project: CSN II
• Duration: 2015 – 2020+


• Local responsible for TIFPA: William Jerome Burger
• Involved TIFPA people: Roberto Battiston, Francesco Maria Follega, Roberto Iuppa, Ignazio Lazzizzera, Christian Manea, Irina Rashevskaya, Ester Ricci


HEPD Flight Model

HEPD Flight Model


NOAA event back-­‐propagation example

NOAA event back-­‐propagation example



Electron and proton acceptances for the HEPD