A. Tykhonov

The test results of the Silicon Tungsten Tracker of DAMPE

V. Gallo∗1, G. Ambrosi2, R. Asfandiyarov1, P. Azzarello1, P. Bernardini3,4, B. Bertucci2,5, A. Bolognini2,5, F. Cadoux1, M. Caprai2, I. De Mitri3,4, M. Domenjoz1, Y. Dong6, M. Duranti2,5, R. Fan6, P. Fusco7,8, F. Gargano7, K. Gong6, D. Guo6, C. Husi1, M. Ionica2,5, D. La Marra1, F. Loparco7,8, G. Marsella3,4, M.N. Mazziotta7,, A. Nardinocchi2,5, L. Nicola1, G. Pelleriti1, W. Peng6, M. Pohl1, V. Postolache2, R. Qiao6, A. Surdo4, A. Tykhonov1, S. Vitillo1, H. Wang6, M. Weber1, D. Wu6, X. Wu1, F. Zhang6

Internal alignment and position resolution of the silicon tracker of DAMPE determined with orbit data

Abstract The DArk Matter Particle Explorer (DAMPE) is a space-borne particle detector designed to probe electrons and gamma-rays in the few GeV to 10 TeV energy range, as well as cosmic-ray proton and nuclei components between 10 GeV and 100 TeV. The silicon–tungsten tracker–converter is a crucial component of DAMPE. It allows the direction of incoming photons converting into electron–positron pairs to be estimated, and the trajectory and charge (Z) of cosmic-ray particles to be identified. It consists of 768 silicon micro-strip sensors assembled in 6 double layers with a total active area of 6.6 m 2 . Silicon planes are interleaved with three layers of tungsten plates, resulting in about one radiation length of material in the tracker. Internal alignment parameters of the tracker have been determined on orbit, with non-showering protons and helium nuclei. We describe the alignment procedure and present the position resolution and alignment stability measurements.

Offline software for the DAMPE experiment

A software framework has been developed for the DArk Matter Particle Explorer (DAMPE) mission, a satellite based experiment. The software framework of DAMPE is mainly written in C++, while the application under this framework is steered in Python script. The framework is comprised of four principal parts: event data module which contains all reconstruction and simulation information based on ROOT input/output (I/O) streaming; a collection of processing models which are used to process each event data, called as algorithms; service module, a series of common tools which provide general functionalities like data communication between algorithms; and event filters. This article presents an overview of the DAMPE offline software framework, and the major architecture design choices during the development. The whole system has been applied to DAMPE data analysis successfully, based on which some results from simulation and beam test experiments are also shown in this article.

In-flight performance of the DAMPE silicon tracker

Abstract DAMPE (DArk Matter Particle Explorer) is a spaceborne high-energy cosmic ray and gamma-ray detector, successfully launched in December 2015. It is designed to probe astroparticle physics in the broad energy range from few GeV to 100 TeV. The scientific goals of DAMPE include the identification of possible signatures of Dark Matter annihilation or decay, the study of the origin and propagation mechanisms of cosmic-ray particles, and gamma-ray astronomy. DAMPE consists of four sub-detectors: a plastic scintillator strip detector, a Silicon–Tungsten tracKer–converter (STK), a BGO calorimeter and a neutron detector. The STK is composed of six double layers of single-sided silicon micro-strip detectors interleaved with three layers of tungsten for photon conversions into electron–positron pairs. The STK is a crucial component of DAMPE, allowing to determine the direction of incoming photons, to reconstruct tracks of cosmic rays and to estimate their absolute charge (Z). We present the in-flight performance of the STK based on two years of in-flight DAMPE data, which includes the noise behavior, signal response, thermal and mechanical stability, alignment and position resolution.

Reconstruction software of the silicon tracker of DAMPE mission

DAMPE is a satellite-borne experiment aimed to probe astroparticle physics in the GeV-TeV energy range. The Silicon tracker (STK) is one of the key components of DAMPE, which allows the reconstruction of trajectories (tracks) of detected particles. The non-negligible amount of material in the tracker poses a challenge to its reconstruction and alignment. In this paper we describe methods to address this challenge. We present the track reconstruction algorithm and give insight into the alignment algorithm. We also present our CAD-to-GDML converter, an in-house tool for implementing detector geometry in the software from the CAD drawings of the detector.