The DArk Matter Particle Explorer mission

Abstract: The DArk Matter Particle Explorer (DAMPE), one of the four scientific space science missions within the framework of the Strategic Pioneer Program on Space Science of the Chinese Academy of Sciences, is a general purpose high energy cosmic-ray and gamma-ray observatory, which was successfully launched on December 17th, 2015 from the Jiuquan Satellite Launch Center. The DAMPE scientific objectives include the study of galactic cosmic rays up to $\sim 10$ TeV and hundreds of TeV for electrons/gammas and nuclei respectively, and the search for dark matter signatures in their spectra. In this paper we illustrate the layout of the DAMPE instrument, and discuss the results of beam tests and calibrations performed on ground. Finally we present the expected performance in space and give an overview of the mission key scientific goals.

• The paper presents DAMPE’s comprehensive measurement approach using a multi-component detector system to accurately capture high-energy cosmic rays and gamma rays.
• It highlights the integration of the PSD, STK, BGO, and NUD instruments for precise particle identification and trajectory reconstruction, achieving angular resolutions below 80 micrometers.
• The mission’s results refine cosmic-ray propagation models and dark matter research through rigorous calibration and state-of-the-art energy reconstruction techniques.

Insights into the DArk Matter Particle Explorer Mission

The paper focuses on the DArk Matter Particle Explorer (DAMPE), a high-energy cosmic-ray and gamma-ray observatory. Launched in 2015, it is designed to study phenomena such as galactic cosmic rays and dark matter, examining particles with exceptional precision and range.

Instrumentation and Architecture

DAMPE comprises four main components: the Plastic Scintillator strip Detector (PSD), the Silicon-Tungsten tracKer-converter (STK), the BGO imaging calorimeter, and the NeUtron Detector (NUD). Each component serves specific functions, contributing to DAMPE's comprehensive detection and measurement capabilities.

1. Plastic Scintillator strip Detector (PSD): The PSD identifies the charge of cosmic-ray particles and acts as an anti-coincidence detector for gamma-ray detection. It achieves high charged-particle rejection efficiency and robust dynamic range, supporting accurate cosmic-ray nuclei identification up to iron.
2. Silicon-Tungsten tracKer-converter (STK): The STK improves particle trajectory reconstruction and photon conversion efficiency. Equipped with silicon micro-strip detectors and tungsten layers, it achieves angular resolution below 80 micrometers over a wide incidence range, though charge reconstruction above oxygen remains challenging.
3. BGO Imaging Calorimeter: This core component of DAMPE measures energy deposition, providing electron/hadron discrimination and triggering data acquisition. The calorimeter's design supports a dynamic range that processes electron energies up to 10 TeV without saturation, ensuring accurate measurement and data correlation.
4. NeUtron Detector (NUD): The NUD further aids electron/hadron discrimination, capitalizing on neutron activity differences in hadronic vs. electromagnetic showers. Its complementarity enhances DAMPE's particle identification capabilities.

Performance and Calibration

Through extensive ground calibration, including CERN beam tests, DAMPE's instruments are rigorously verified. These tests validate performance specifications such as energy resolution, charge accuracy, and angular precision. Energy reconstruction is notably refined, accounting for material influence on readings, and leveraging sophisticated correction algorithms stemming from longitudinal shower profiling.

Scientific Objectives

DAMPE's mission focuses on several pivotal astrophysical investigations:

• Cosmic-Ray Origin and Propagation: By measuring spectra of electrons, positrons, and various nuclei up to 100 TeV with high precision, DAMPE explores cosmic-ray acceleration and diffusion processes. Its findings contribute to refining models of cosmic-ray sources and propagation mechanisms.
• Dark Matter Research: DAMPE probes potential dark matter signatures, including spectral anomalies in cosmic rays and gamma rays. Its high energy resolution enhances the search for gamma-ray lines or spectral features indicative of dark matter interactions.
• High-Energy Gamma-ray Phenomena: DAMPE observes astrophysical transients and diffuse emissions at high energies, offering insights into the mechanisms of active galaxies, SNRs, and potentially GRB-related phenomena.

Future Prospects

The DAMPE mission sets a precedent for precision in space-based observations of high-energy particles. Its contributions are anticipated to bolster theoretical models in cosmic-ray physics and dark matter, while opening avenues for the pursuit of unresolved astrophysical questions. Continuous improvements in data analysis and calibration are expected to refine its capabilities further, sustaining its relevance in the astroparticle physics community.