Advancing dark matter detection: Innovative LYSO crystal calorimeter enhances the dark photon search sensitivity
LYSO-based calorimeter improves detection sensitivity for dark photons in DarkSHINE experiment
image: Figure.1 illustrates the conceptual mechanism of dark-photon production via dark bremsstrahlung and its subsequent decay into invisible dark matter, forming the experimental basis for DarkSHINE, which will leverages the high-repetition-rate single-electron beam provided by the Shanghai High Repetition-Rate XFEL and Extreme Light Facility (SHINE).
Credit: Shu Li
Researchers from Tsung-Dao Lee Institute (TDLI) & School of Physics and Astronomy (SPA), Shanghai Jiao Tong University (SJTU) has designed and optimized a LYSO crystal-based electromagnetic calorimeter (ECAL) for the DarkSHINE experiment. The ECAL aims to detect the invisible decay products of dark photons by measuring the energy loss of recoil electrons, a key experimental signature. With its superior energy resolution and high energy absorption efficiency, the ECAL offers strong discrimination power between dark photon signals and backgrounds. The intrinsic performance of LYSO crystals—combining high light yield, fast scintillation decay time and strong radiation hardness—ensures reliable operation in the high-repetition-rate and high-radiation environment anticipated in DarkSHINE.
Probing Sub-GeV Dark Matter
Dark matter remains one of the biggest mysteries in physics and cosmology, comprising the majority of the universe’s matter content while continuing to evade direct detection. Recent theories suggest that dark photons could provide a crucial link between visible and invisible matter. However, traditional detection methods face significant challenges, especially when targeting dark matter in sub-GeV mass range. The LYSO ECAL addresses these challenges through precise measurements on missing energy of recoil electrons, enhanced sensitivity for dark photon detection.
" This detector significantly enhances precision and sensitivity of dark photon searches in future DarkSHINE experiment," said Zhiyu ZHAO (T.D. Lee honorary PhD student of TDLI, Advisor: Shu Li), "Our optimized ECAL design ensures precise energy measurements, critical for distinguishing potential dark photon signals from background contaminations."
Optimized Design for High Performance
Through comprehensive simulation studies, the team established an optimal ECAL design comprising 21×21×11 LYSO crystals (2.5×2.5×4 cm³ each), segmented in a staggered geometry. This design maximizes energy resolution and detection efficiency for dark photons, while maintaining a balance between performance and material cost. Each crystal is read out by a silicon photomultiplier (SiPM), enabling compact, fast, and high-resolution signal detection.
The ECAL is expected to achieve an energy resolution better than 2%/√E (statistical term), enabling precise measurements of rare signal events against overwhelming backgrounds.
Built for Harsh Environments
The demanding beam conditions of future DarkSHINE operations require detectors with both fast timing and strong radiation tolerance. The LYSO ECAL meets these needs through the material’s short scintillation decay time and proven resistance to radiation damage. The ECAL maintains stable performance under radiation dose exceeding 10 million rad, making it suitable for long-term operation in high-intensity experiments.
Outlook and Impact
This calorimeter enhances sensitivity to dark photon signals and contributes a valuable advancement in detector technology for particle physics. The design methodology may offer good references for future high-energy physics experiments.
“We hope our work will provide a practical foundation for future studies in dark matter detection,” said Zhiyu ZHAO, “The DarkSHINE ECAL highlights the importance of developing robust, high-performance calorimetry detectors to support ongoing exploration of dark matter mystery being one of the key scientific puzzles in fundamental physics.”
The complete study is accessible via DOI: 10.1007/s41365-024-01618-8.