A novel remotely operated vehicle as the calibration system in JUNO

Abstract

The Jiangmen Underground Neutrino Observatory (JUNO) is a multifunctional neutrino-oscillation experiment, aiming to determine the neutrino mass hierarchy and precisely measure three neutrino oscillation parameters, of which the calibration system is essential to the response of the detector. This paper presents a calibration system consisting of Remotely Operated Vehicles and Sonar Positioning System, focusing on the positioning of the Remotely Operated Vehicles. The design principles and theoretical analysis are discussed as well as specific requirements. The corresponding motion control mode is then proposed. The experiment is further performed to validate the accuracy of horizontal and vertical positioning devices. It is shown that the designed device can satisfy the harsh requirements from JUNO, including radioaction, compatibility, and magnetic effects. The speed limit (1 m/min) at the horizontal plane and positioning accuracy (30 mm/5 min) in three dimensions are also ensured, indicating the performance of the calibration system is well tested. The motion control of the positioning device in the liquid scintillator environment is finally predicted. The proposed Remotely Operated Vehicle together with the Sonar Positioning System can provide the calibration operation in JUNO.

Calibration Strategy for the JUNO Experiment

“…Two dedicated off-axis systems have been created to monitor the detector non-uniformity and perform two-dimensional scans: the Cable Loop System (CLS) [5], movable on a vertical half-plane, and the Guide Tube system (GT) [6,7], surrounding the outside regions of the CD. To complete the hardware system, a Remotely Operated under-LS Vehicle (ROV) [8] will be deployed to the selected locations to investigate spatial non-uniformity, being capable of deploying a radioactive source in almost the entire LS volume.…”

The automatic calibration unit in JUNO

“…Several calibration hardware subsystems have been previously reported in refs. [12][13][14][15]. In this paper, we discuss one of the key components of the calibration system, the ACU, envisioned as a primary tool to perform detector calibration on a regular basis.…”

The Automatic Calibration Unit in JUNO

“…Several hardware subsystems have been previously reported in Refs. [12][13][14][15]. In this paper, we discuss one of the key components of the calibration system, the ACU, envisioned as a primary tool to perform detector calibration on a regular basis.…”