Speaker
Description
The High-Energy Particle Detectors (HEPDs) onboard the China Seismo-Electromagnetic Satellite (CSES) mission are designed to study charged particle fluxes in space. The first-generation instrument, HEPD-01 on CSES-01, was originally conceived to measure low-energy electrons and protons but has also demonstrated the ability to detect transient phenomena such as Gamma-Ray Bursts (GRBs). By analyzing anomalous fluctuations in the rate meters of its trigger system, HEPD-01 successfully identified several GRB events, which were confirmed by other independent space-borne instruments. These observations were recently compiled into a dedicated GRB catalog providing information in the energy range 0.3–50MeV scarcely covered by other instruments.
Building on these results, the next-generation HEPD-02 on CSES-02 introduces significant improvements to enhance GRB detection. The new instrument features an expanded LYSO calorimeter, extending the energy range for fully contained photon events, and a dedicated onboard trigger algorithm capable of autonomously registering transient signals with millisecond resolution. The combined use of the LYSO calorimeter and the plastic scintillators of the Range Detector (RAN) allows for a more detailed analysis of event topologies, improving gamma-ray interaction reconstruction. In particular, HEPD-02 will be sensitive to gamma photons starting at approximately 0.5 MeV, with a peak effective area of $~$130 cm$^2$ near 30 MeV.
In this contribution, we present the GRB detection methodology and key findings from HEPD-01, highlighting its contributions to the field and the ongoing efforts to refine its detection capabilities. We will also discuss how these results have guided the development of HEPD-02, detailing the upgrades incorporated in this second-generation instrument. Furthermore, we will showcase the architectural design of HEPD-02 and its custom-developed trigger algorithm for transient detection, illustrating how these advancements enhance the detector’s performance in monitoring GRBs.
| Collaboration(s) | On behalf of the CSES-Limadou collaboration |
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