Automatic scanning of nuclear emulsions with wide-angle acceptance for nuclear fragment detection

TL;DR

This paper introduces a novel automated nuclear emulsion scanning system with wide-angle acceptance up to |tanθ|<3.0, utilizing GPU technology to improve detection of nuclear fragments and enhance particle physics experiments like OPERA.

Contribution

The system achieves wide-angle track recognition in nuclear emulsions and employs GPU-based algorithms, surpassing previous angular limitations and increasing analysis efficiency.

Findings

Recognizes nuclear fragment tracks at |tanθ|<3.0

Uses GPU for fast and flexible track recognition

Reduces background in tau decay detection in OPERA

Abstract

Nuclear emulsion, a tracking detector with sub-micron position resolution, has played a successful role in the field of particle physics and the analysis speed has been substantially improved by the development of automated scanning systems. This paper describes a newly developed automated scanning system and its application to the analysis of nuclear fragments emitted almost isotropically in nuclear evaporation. This system is able to recognize tracks of nuclear fragments up to |tan{\theta}|< 3.0 (where {\theta} is the track angle with respect to the perpendicular to the emulsion film), while existing systems have an angular acceptance limited to |tan{\theta}|< 0.6. The automatic scanning for such a large angle track in nuclear emulsion is the first trial. Furthermore the track recognition algorithm is performed by a powerful Graphics Processing Unit (GPU) for the first time. This GPU has a sufficient computing power to process large area scanning data with a wide angular acceptance and enough flexibility to allow the tuning of the recognition algorithm. This new system will in particular be applied in the framework of the OPERA experiment : the background in the sample of tau decay candidates due to hadronic interactions will be reduced by a better detection of the emitted nuclear fragments.