Mass Testing and Characterization of 20-inch PMTs for JUNO

Abstract

Main goal of the JUNO experiment is to determine the neutrino mass ordering using a 20 kt liquid-scintillator detector. Its key feature is an excellent energy resolution of at least 3 % at 1 MeV, for which its instruments need to meet a certain quality and thus have to be fully characterized. More than 20,000 20-inch PMTs have been received and assessed by JUNO after a detailed testing program which began in 2017 and elapsed for about four years. Based on this mass characterization and a set of specific requirements, a good quality of all accepted PMTs could be ascertained. This paper presents the performed testing procedure with the designed testing systems as well as the statistical characteristics of all 20inch PMTs intended to be used in the JUNO experiment, covering more than fifteen performance parameters including the photocathode uniformity. This constitutes the largest sample of 20-inch PMTs ever produced and studied in detail to date, i.e. 15,000 of the newly developed 20inch MCP-PMTs from Northern Night Vision Technology Co. (NNVT) and 5,000 of dynode PMTs from Hamamatsu Photonics K. K.(HPK).

Energy reconstruction for large liquid scintillator detectors with machine learning techniques: aggregated features approach

“…JUNO will be equipped with two types of 20-inch PMTs: 25% produced by Hamamatsu and 75% by NNVT. The measured dark current rate for the former ones is 19.3 kHz, the latter ones have the dark rate of 49.3 kHz [23]. Different processes during photo-electron collection and further current amplification, as well as intrinsic effects of electronics, are also simulated.…”

“…Different processes during photo-electron collection and further current amplification, as well as intrinsic effects of electronics, are also simulated. The introduced spread of hit times is 1.3 ns and 7.0 ns for Hamamatsu and NNVT respectively [23]. Then the charge and time information is extracted from PMT pulse shapes and serves as input for reconstruction algorithms.…”

Energy reconstruction for large liquid scintillator detectors with machine learning techniques: aggregated features approach

“…JUNO will be equipped with two types of 20-inch PMTs: 25% produced by Hamamatsu and 75% by NNVT. The measured dark current rate for the former is 19.3 kHz; the latter has the dark rate of 49.3 kHz [24]. Different processes during photo-electron collection and further current amplification, as well as intrinsic effects of electronics, are also simulated.…”

“…Different processes during photo-electron collection and further current amplification, as well as intrinsic effects of electronics, are also simulated. The introduced spread of hit times is 1.3 ns and 7.0 ns for Hamamatsu and NNVT, respectively [24]. Then the charge and time information is extracted from PMT pulse shapes and serves as an input for reconstruction algorithms.…”

Imaging of CsI(Tl) crystal event and double-slit Young's interference by a single photon sensitive camera

“…Photon detection is one of the fundamental technologies widely used in particle physics, astronomy and industry, such as Super-K [1], KamLAND [2], JUNO [3,4], Hubble [5], clinically and preclinically [6], X-ray imaging [7] and long-range imaging [8] etc. The reconstruction of vertex and track is critical in most of the particle physics experiments, where it is always trying to use most of information from photons.…”