# Accurate GPS-based timestamp facility for Gran Sasso National Laboratory

## TL;DR

This paper presents a GPS-based timestamp system for underground experiments at Gran Sasso Laboratory, achieving 15 ns accuracy and integrating into the laboratory's infrastructure for precise event timing.

## Contribution

The paper introduces a novel underground timestamping system using GPS synchronization, enhancing timing precision for underground experiments.

## Key findings

- Achieved 15 ns time accuracy (1 sigma)
- Successfully integrated into laboratory infrastructure
- Provides precise reference frequencies

## Abstract

A new system to assign accurate timestamps to events recorded by experiments running underground has been designed, installed and tested at INFN Gran Sasso National Laboratory, Italy. This facility is based on a Master unit installed on surface and receiving time information from a GPS receiver, and Slave units placed underground which get data packet from the Master via optical fiber and assign the timestamps. The system is able to provide a time accuracy of 15 ns (1 $\sigma$) and precise reference frequencies to the experiments. It is now part of the infrastructure of the Laboratory for all the experimental activities which need accurate timestamps.