The Calibration Units of KM3NeT

TL;DR

This paper details the design and purpose of calibration units for KM3NeT's neutrino telescopes, focusing on ensuring precise positioning and timing calibration in a challenging deep-sea environment.

Contribution

It introduces the design and features of the calibration units tailored for KM3NeT's ARCA and ORCA detectors, emphasizing the ORCA calibration system.

Findings

Calibration units enable nanosecond timing precision.

Positioning accuracy is maintained despite sea currents.

Design differences accommodate the size disparity between ARCA and ORCA.

Abstract

KM3NeT is a deep-sea infrastructure composed of two neutrino telescopes being deployed in the Mediterranean Sea: ARCA, near Sicily in Italy, designed for neutrino astronomy, and ORCA, near Toulon in France, designed for neutrino oscillation physics. To achieve the best performance, the exact location of the optical modules, affected by sea current, must be known at any time and the timing resolution between optical modules must reach the nanosecond. Moreover, the properties of the environment in which the telescopes are deployed must be continuously monitored because they affect the timing and positioning calibration. KM3NeT is going to deploy several dedicated Calibration Units to meet these calibration goals. Because of the difference in size between ARCA and ORCA, the design of the Calibration Unit is not the same for the two sites. This proceeding describes all the devices, features and purposes of the Calibration Units with a focus on the ORCA Calibration Unit.