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

TL;DR

This paper details the on-orbit alignment process of DAMPE's silicon tracker, demonstrating improved position resolution and stability crucial for accurate cosmic-ray and gamma-ray measurements.

Contribution

It introduces a novel on-orbit alignment method for DAMPE's silicon tracker, enhancing its positional accuracy and stability based on orbit data.

Findings

Alignment parameters achieved high precision

Position resolution improved after alignment

Stable alignment maintained over time

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.