Valentina Gallo

Design of the readout electronics for the DAMPE Silicon Tracker detector

The Silicon Tracker (STK) is a detector of the DAMPE satellite to measure the incidence direction of high energy cosmic ray. It consists of 6 X-Y double layers of silicon micro-strip detectors with 73,728 readout channels. Its a great challenge to readout the channels and process the huge volume of data in the critical space environment. 1152 Application Specific Integrated Circuits (ASIC) and 384 ADCs are adopted to readout the detector channels. The 192 Tracker Front-end Hybrid (TFH) modules and 8 identical Tracker Readout Board (TRB) modules are designed to control and digitalize the front signals. In this paper, the design of the readout electronics for STK and its performance will be presented in detail.

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.

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.

Measurement of cosmic-ray charge with the DAMPE Silicon-Tungsten Tracker

The DArk Matter Particle Explorer (DAMPE) satellite is a powerful space detector launched on December 17 2015. The main objectives of the mission are in the research for Dark Matter signatures thanks to the detection of electrons and photons in an energy range going from few GeV up to 10 TeV. Moreover, insights on the origin and propagation mechanisms of cosmic rays are also expected thanks to nuclei flux measurements up to 100 TeV. In this context the charge (Z) measurement is crucial to distinguish the different chemical components of cosmic rays and to check the models of propagation in the galaxy. The DAMPE detector is composed of the following sub-detectors: a Plastic Strip scintillator Dectector (PSD), a Silicon-Tungsten tracKer (STK), a Bismuth Germanium Oxide (BGO) imaging calorimeter, and a NeUtron Detector (NUD). The Z-measurement is performed by the PSD and the STK. In this document after a detailed description of the STK, the first results on the absolute ion charge identification using more than one year of STK on-orbit data are discussed, together with the applied calibration procedure.

Studies on Helium flux with DAMPE

Since December 2015 the DAMPE (DArk Matter Particle Experiment) detector is on-orbit at an altitude of 500 km and takes data smoothly. It consists of a Plastic Scintillator strip Detector (PSD), a Silicon-Tungsten tracKer-converter (STK), a BGO imaging calorimeter and a NeUtron Detector (NUD). The charge of incident cosmic rays (CRs) is measured by looking at the energy deposited in the PSD, and the tracks are reconstructed thanks to the high spatial resolution of the STK. The remarkable depth (32 radiation lengths) of the calorimeter allows for an estimate of the CR energy. Then the DAMPE features are suitable to distinguish the elemental composition of CRs and to measure their fluxes in the energy range of 20 GeV - 100 TeV. Here the analysis progress in the study of the Helium component will be presented and discussed.

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.