The OPERA global readout and GPS distribution system

TL;DR

The paper describes the design and implementation of a sophisticated, synchronized, and distributed readout and GPS timing system for the OPERA neutrino oscillation experiment, enabling precise data collection and event synchronization.

Contribution

It introduces a novel global readout architecture using Ethernet-capable sensors and a GPS-locked clock system for large-scale particle physics experiments.

Findings

Successful deployment of a triggerless, continuous readout system.

Precise synchronization of all detector channels via GPS.

Enhanced data acquisition reliability and timing accuracy.

Abstract

OPERA is an experiment dedicated to the observation of $\nu_\mu$ into $\nu_\tau$ oscillations in appearance mode using a pure $\nu_\mu$ beam (CNGS) produced at CERN and detected at Gran Sasso. The experiment exploits a hybrid technology with emulsions and electronics detectors \cite{opera}. The OPERA readout is performed through a triggerless, continuously running, distributed and highly available system. Its global architecture is based on Ethernet-capable smart sensors with microprocessing and network interface directly at the front-end stage. An unique interface board is used for the full detector reading out ADC-, TDC- or Controller-boards. All the readout channels are synchronized through a GPS-locked common bidirectional clock distribution system developped on purpose in a PCI format. It offers a second line to address all channels and the off-line synchronization with the CNGS to select the events.