The Double Chooz antineutrino detectors

Abstract

This article describes the setup and performance of the near and far detectors in the Double Chooz experiment. The electron antineutrinos of the Chooz nuclear power plant were measured in two identically designed detectors with different average baselines of about 400 m and 1050 m from the two reactor cores. Over many years of data taking the neutrino signals were extracted from interactions in the detectors with the goal of measuring a fundamental parameter in the context of neutrino oscillation, the mixing angle $$\theta _{13}$$ θ 13 . The central part of the Double Chooz detectors was a main detector comprising four cylindrical volumes filled with organic liquids. From the inside towards the outside there were volumes containing gadolinium-loaded scintillator, gadolinium-free scintillator, a buffer oil and, optically separated, another liquid scintillator acting as veto system. Above this main detector an additional outer veto system using plastic scintillator strips was installed. The technologies developed in Double Chooz were inspiration for several other antineutrino detectors in the field. The detector design allowed implementation of efficient background rejection techniques including use of pulse shape information provided by the data acquisition system. The Double Chooz detectors featured remarkable stability, in particular for the detected photons, as well as high radiopurity of the detector components.

Characterization of the TruSense S310 laser range system for contact-less measurement of liquid levels in large-volume neutrino detectors

“…The dismantling of the Near Detector of the Double Chooz reactor neutrino experiment [5] offered the opportunity to perform a sensor test under the operation conditions of a full-scale neutrino experiment. The TruSense S310 was mounted on top of an acrylic pipe (Detector Chimney) reaching down into the central liquid scintillator volume, the Neutrino Target (see [5] for details).…”

“…The dismantling of the Near Detector of the Double Chooz reactor neutrino experiment [5] offered the opportunity to perform a sensor test under the operation conditions of a full-scale neutrino experiment. The TruSense S310 was mounted on top of an acrylic pipe (Detector Chimney) reaching down into the central liquid scintillator volume, the Neutrino Target (see [5] for details). The laser range system was mounted in the position of the mechanical level measurement system (Tamago, Proservo NMS5) shown in the left panel of figure 8 (taken from [5]), using a customized mechanical fixation for the laser sensor.…”

“…Section 4 presents a series of laboratory experiments dedicated to evaluate the performance of the TruSense S310: short-term precision and long-term stability of the measurement and finally the simultaneous operation of the IR laser with standard bi-alkali photomultiplier tubes (PMTs). Section 5 reports the results of a test deployment of the TruSense S310 in the realistic detector environment of the Double-Chooz Near Detector setup [5]. This in-situ trial run of the system became possible during the draining operations for the Near Detector, permitting a comparison of the capabilities of the laser-range system with a standard hydrostatic pressure sensor.…”

Calibration of photomultiplier tubes

“…A prime example of this case is the ten inches Hamamatsu R7081 photomultiplier tube (PMT) model that has been used in several experiments in particle physics. Double Chooz, RENO and IceCube to name only but a few [1][2][3]. It is known to operate at a nominal gain of 10 7 units of electron charge for about 1500 V of high voltage.…”

The acrylic vessel for JSNS2-II neutrino target

“…Since different liquids are used for the target and the catcher regions, the detector target region must be separated physically, and transparent to allow photons to pass through. Similar to successful designs in reactor neutrino experiments [5][6][7], an acrylic vessel is chosen to separate the JSNS 2 target region.…”