We summarize the recent activity of our group in the calibration, monitoring and gain stabilization of photodetectors, primarily silicon photomultipliers, in calorimeters using scintillator as active medium. The task originally solved for the CALICE analog hadron calorimeter founds application in other experiments.
The Daya Bay Reactor Neutrino Experiment has measured the last unknown neutrino mixing angle, {theta}13, to be non-zero at the 7.7{sigma} level. This is the most precise measurement to {theta}13 to date. To further enhance the understanding of the response of the antineutrino detectors (ADs), a detailed calibration of an AD with the Manual Calibration System (MCS) was undertaken during the summer 2012 shutdown. The MCS is capable of placing a radioactive source with a positional accuracy of 25 mm in R direction, 20 mm in Z axis and 0.5{deg} in {Phi} direction. A detailed description of the MCS is presented followed by a summary of its performance in the AD calibration run.
Jiangmen Underground Neutrino Observatory (JUNO) is designed to determine the neutrino mass hierarchy using a 20 kton liquid scintillator detector. To calibrate detector boundary effect, the Guide Tube Calibration System (GTCS) has been designed to deploy a radioactive source along a given longitude on the outer surface of the detector. In this paper, we studied the physics case of this system via simulation, which leads to a mechanical design.
A cable loop source calibration system is developed for the Jiangmen Underground Neutrino Observatory, a 20 kton spherical liquid scintillator neutrino experiment. This system is capable of deploying radioactive sources into different positions of the detector in a vertical plane with a few-cm position accuracy. The design and the performance of the prototype are reported in this paper.
The MAJORANA Collaboration is searching for the neutrinoless double-beta decay of the nucleus $^{76}$Ge. The MAJORANA DEMONSTRATOR is an array of germanium detectors deployed with the aim of implementing background reduction techniques suitable for a 1-tonne $^{76}$Ge-based search. The ultra low-background conditions require regular calibrations to verify proper function of the detectors. Radioactive line sources can be deployed around the cryostats containing the detectors for regular energy calibrations. When measuring in low-background mode, these line sources have to be stored outside the shielding so they do not contribute to the background. The deployment and the retraction of the source are designed to be controlled by the data acquisition system and do not require any direct human interaction. In this paper, we detail the design requirements and implementation of the calibration apparatus, which provides the event rates needed to define the pulse-shape cuts and energy calibration used in the final analysis as well as data that can be compared to simulations.
A Guide Tube Calibration System (GTCS) has been designed for the Jiangmen Underground Neutrino Observatory (JUNO), in order to measure the detector energy response near the outer radius of the active volume. Recently, a prototype system has been constructed and tested, and the calibration algorithm has also been studied to evaluate the risk when the simulation tuning and the error control fail. In this paper, we first report its construction and the performance tests in the lab. Then the influence on the global energy measurement caused by the simulation bias of GTCS is discussed, in order to make sure the algorithm is qualified.