An event display for the Transition Radiation Detector in ALICE

Abstract

Abstract Particle collider experiments generate huge volumes of complex data, and event displays provide a useful visual representation to accelerate the learning process towards physics results. Event displays are also used to verify expected behaviour, identify anomalous data, or explain important results. They often have a steep learning curve, a high barrier to entry, or are tightly bound to a specific environment. The upgrade of ALICE in preparation for Run 3 of the LHC requires modifications to existing event displays. We present here a cross-platform, browser-based event display, focused on interactive 2-dimensional projections of collision data from ALICE, specifically focused on the operation of the Transition Radiation Detector (TRD). It is driven by a flexible intermediate JSON data format suitable for web-based displays, and a generic task to convert existing data acquired in previous runs to this format. The relationship between raw and reconstructed data in the TRD is illustrated through a novel pairing of raw and reconstructed data in a unified interactive view. A formal design study methodology was used to guide these choices, and the display was evaluated by both scientists and the public, through a series of case studies.