The ALICE Transition Radiation Detector: status and perspectives for Run II

TL;DR

The ALICE Transition Radiation Detector enhances particle tracking and identification in high-energy physics experiments, with recent upgrades improving its coverage and performance for Run II data collection.

Contribution

This paper reports on the status, upgrades, and performance of the ALICE TRD, highlighting its full azimuthal coverage and readiness for Run II.

Findings

Successful electron identification and triggering in Run I

Full azimuthal coverage achieved after upgrades

Detector performance met expectations for Run II

Abstract

The ALICE Transition Radiation Detector contributes to the tracking, particle identification, and triggering capabilities of the experiment. It is composed of six layers of multi-wire proportional chambers, each of which is preceded by a radiator and a Xe/CO$_2$-filled drift volume. The signal is sampled in timebins of 100~ns over the drift length which allows for the reconstruction of chamber-wise track segments, both online and offline. The particle identification is based on the specific energy loss of charged particles and additional transition radiation photons, the latter being a signature for electrons. The detector is segmented into 18 sectors, of which 13 were installed in Run I. The TRD was included in data taking since the LHC start-up and was successfully used for electron identification and triggering. During the Long Shutdown 1, the detector was completed and now covers the full azimuthal acceptance. Furthermore, the readout and trigger components were upgraded. When data taking was started for \runii{}, their performance fulfilled the expectations.