Beam Test Characterization of Silicon Microstrip Detector Flight-Model Ladders for the AMS-02 Upgrade

TL;DR

This paper evaluates the performance of silicon microstrip detector ladders for the AMS-02 upgrade using CERN beam tests, focusing on spatial resolution, response uniformity, and angle dependence.

Contribution

It provides a detailed performance characterization of flight-model silicon microstrip detector ladders for the AMS-02 experiment, including resolution and response consistency.

Findings

Spatial resolution varies from 9.5 to 11.4 micrometers depending on the number of SSDs.

Detector response is consistent across different ladder regions.

Performance depends on particle incidence angle.

Abstract

The AMS-02 experiment plans to install a new silicon microstrip tracker layer (Layer-0) on top of the existing detector, increasing the cosmic-ray acceptance by a factor of 3. Layer-0 employs a design in which multiple silicon microstrip detectors (SSDs) are connected in series to form long detector ladders. We present a detailed performance study of the flight-model ladders using a 350~GeV mixed hadron beam at the CERN SPS. The study focuses on the following aspects: (i) the performance of ladders with different numbers of SSDs, for which the intrinsic spatial resolution at normal incidence varies from $9.5~\mu\mathrm{m}$ to $11.4~\mu\mathrm{m}$ for ladders composed of 8 to 12 SSDs; (ii) the response consistency for particles impacting on the \emph{Head} and \emph{Tail} regions of the ladder; and (iii) the dependence of the detector performance on the particle incidence angle.