The DArk Matter Particle Explorer mission

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.Comment: 45 pages, including 29 figures and 6 tables. Published in Astropart. Phy

Direct detection of a break in the teraelectronvolt cosmic-ray spectrum of electrons and positrons

High energy cosmic ray electrons plus positrons (CREs), which lose energy quickly during their propagation, provide an ideal probe of Galactic high-energy processes and may enable the observation of phenomena such as dark-matter particle annihilation or decay. The CRE spectrum has been directly measured up to $\sim 2$ TeV in previous balloon- or space-borne experiments, and indirectly up to $\sim 5$ TeV by ground-based Cherenkov $\gamma$-ray telescope arrays. Evidence for a spectral break in the TeV energy range has been provided by indirect measurements of H.E.S.S., although the results were qualified by sizeable systematic uncertainties. Here we report a direct measurement of CREs in the energy range $25~{\rm GeV}-4.6~{\rm TeV}$ by the DArk Matter Particle Explorer (DAMPE) with unprecedentedly high energy resolution and low background. The majority of the spectrum can be properly fitted by a smoothly broken power-law model rather than a single power-law model. The direct detection of a spectral break at $E \sim0.9$ TeV confirms the evidence found by H.E.S.S., clarifies the behavior of the CRE spectrum at energies above 1 TeV and sheds light on the physical origin of the sub-TeV CREs.Comment: 18 pages, 6 figures, Nature in press, doi:10.1038/nature2447

Machine learning methods for helium flux analysis with DAMPE experiment

DAMPE is a space-borne experiment for the measurement of the cosmic-ray fluxes at energies up to around 100 TeV per nucleon. At energies above several tens of TeV, the electronics of DAMPE calorimeter would saturate, leaving certain bars with no energy recorded. It is also observed that at high energies the tracker and the scintillator detector that serve for the charge identification become heavily populated with back-splash tracks. Both effects interfere in precise measurements of the helium flux at highest energies. In the present contribution we discuss the application of machine learning techniques for the treatment of DAMPE data, to compensate the calorimeter energy lost by saturation and to identify helium events

Charge measurement of cosmic rays by Plastic Scintillator Detector of DAMPE

Plastic Scintillator Detector (PSD) of DArk Matter Particle Explorer (DAMPE) is designed to measure the charge of cosmic-rays and it servers as a veto for gamma-rays. In this work, we present some updated correction methods to further improve the quality of PSD charge measurement, especially for heavy nuclei. DAMPE has collected nearly 10 billions events by middle of 2021, it has substantial potential to measure the spectra of cosmic ray nuclei up to hundreds of TeV energies. These measurements could largely benefit from the correction of the PSD signal

Direct Measurement of the Cosmic-Ray Iron Spectrum with the Dark Matter Particle Explorer

Dark Matter Particle Explorer(DAMPE) is a calorimetric-type, satellite-borne detector for observations of high energy electrons, gamma-rays, and cosmic-ray nuclei. Using five years data collected with DAMPE from January 1, 2016 to December 31, 2020, we analyzed the spectrum of iron. Detailed studies of the fragmentation of iron in the detector have been performed using Monte Carlo simulations

Search for gamma-ray lines in the Galaxy with DAMPE

DArk Matter Particle Explorer (DAMPE) has a great potential in the search of monochromatic and sharp gamma-ray structures in GeV-TeV range thanks to its good energy resolution. In this work, we search for gamma-ray line structures using 5.0 years of DAMPE data. To improve the sensitivity, we develop two types of data sets and adopt the signal-to-noise ratio optimized regions of interest (ROIs) for different DM density profiles. No line signals or candidates, including those located at 133 GeV and 43 GeV, are found between 10 GeV and 300 GeV in the Galaxy. Therefore we calculate the 95% confidence level constraints on the velocity-averaged cross section for χχ → γγ and the decay lifetime for χ → γν with systematic uncertainties included. Our constraints on DM parameters are mostly comparable to the Fermi-LAT 5.8-yr results. The lower limit for DM decay lifetime below 100 GeV are better than that of Fermi-LAT

Performance of the DAMPE silicon-tungsten tracker-converter during the first 5 years of in-orbit operations

Since its launch, in December 2015, the satellite-based DAMPE (DArk Matter Particle Explorer) particle detector is taking data smoothly. The Silicon-Tungsten tracKer-converter (STK) of DAMPE consists of six tracking planes (6x, 6y) of single-sided silicon micro-strip detectors mounted on seven support trays. The STK is able to measure the charge and precisely reconstruct the track of traversing charged particles. Tungsten plates (1 mm thick) are integrated in the second, third and fourth tray from the top to serve as γ → e+e- converters. Commissioned rapidly after the launch, the STK is running extremely well since then. The STK in-orbit calibration and performance during its first more than 5 years of operation, including the noise behaviour and the thermal and mechanical stability, are presented in this contribution