arXiv subjects

Xiaoping Jing

Publications and source records attributed to Xiaoping Jing.

7 recordsLinked to original sources

arXiv2026

Realistic Detector Geometry Modeling and Its Impact on Event Reconstruction in JUNO

JUNO is designed to determine the neutrino mass ordering with an energy resolution of 3% at 1 MeV. In the real detector, however, deformations of the central stainless-steel structure during installation lead to deviations of the photomultiplier tube (PMT) positions from their design values. Based on the limited survey data of the PMTs and the stainless-steel truss, we perform a correlation analysis of the measured points and propose a method to predict the positions of all PMTs. Using the resulting realistic geometry, we demonstrate that the detector deformation has a negligible effect on the energy reconstruction. In contrast, inaccuracies in the assumed geometry can introduce vertex biases of up to 40 mm. Incorporating the realistic geometry into the calibration-based PMT response model removes this bias and preserves the stability of the reconstruction algorithms.

physics.ins-det↗

arXiv2025

A highly sensitive SF$_6$-based leak test system for JUNO 3-inch PMT underwater electronics boxes

A total of 25600 3-inch photomultiplier tubes (PMTs), along with their corresponding frontend electronics, have been installed at the Jiangmen Underground Neutrino Observatory (JUNO). These electronics are housed in 200 stainless steel boxes that operate underwater. To verify the sealing integrity of the underwater boxes following integration, we developed an SF$_6$-based leak test system, opting against the typical helium-based system due to helium's ability to penetrate the PMT glass. After a few hours of accumulating leaking SF$_6$ from the underwater boxes, a leak rate detection limit of $2.3\times{10}^{-9}$~Pa$\cdot$m$^3$/s in terms of SF$_6$ was achieved, corresponding to $1.65\times{10}^{-8}$~Pa$\cdot$ m$^3$/s helium equivalent. This meets the sensitivity requirement of 1$\times$10$^{-7}$~Pa$\cdot$m$^3$/s. This system was critical in identifying and replacing a few cases of leaking underwater boxes before installation.

physics.ins-det↗

arXiv2025

The High Voltage Splitter board for the JUNO SPMT system

The Jiangmen Underground Neutrino Observatory (JUNO) in southern China is designed to study neutrinos from nuclear reactors and natural sources to address fundamental questions in neutrino physics. Achieving its goals requires continuous operation over a 20-year period. The small photomultiplier tube (small PMT or SPMT) system is a subsystem within the experiment composed of 25600 3-inch PMTs and their associated readout electronics. The High Voltage Splitter (HVS) is the first board on the readout chain of the SPMT system and services the PMTs by providing high voltage for biasing and by decoupling the generated physics signal from the high-voltage bias for readout, which is then fed to the front-end board. The necessity to handle high voltage, manage a large channel count, and operate stably for 20 years imposes significant constraints on the physical design of the HVS. This paper serves as a comprehensive documentation of the HVS board: its role in the SPMT readout system, the challenges in its design, performance and reliability metrics, and the methods employed for production and quality control.

physics.ins-det↗

arXiv2024

Mass production and performance study on the 20-inch PMT acrylic protection covers in JUNO

The Jiangmen Underground Neutrino Observatory is a neutrino experiment that incorporates 20,012 20-inch photomultiplier tubes (PMTs) and 25,600 3-inch PMTs. A dedicated system was designed to protect the PMTs from an implosion chain reaction underwater. As a crucial element of the protection system, over 20,000 acrylic covers were manufactured through injection molding, ensuring high dimensional precision, mechanical strength, and transparency. This paper presents the manufacturing technology, mass production process, and performance characteristics of the acrylic covers.

physics.ins-det↗

arXiv2022

Design of the PMT underwater cascade implosion protection system for JUNO

Photomultiplier tubes (PMTs) are widely used underwater in large-scale neutrino experiments. As a hollow glass spherelike structure, implosion is unavoidable during long-term operation under large water pressure. There is a possibility of cascade implosion to neighbor PMTs due to shockwave. Jiangmen Underground Neutrino Observatory designed a protection structure for each 20-inch PMT, consisting of a top cover, a bottom cover, and their connection. This paper introduces the requirement and design of the PMT protection system, including the material selection, investigation of manufacture technology, and prototyping. Optimization and validation by simulation and underwater experiments are also presented.

physics.ins-det↗

arXiv2021

Mass production and characterization of 3-inch PMTs for the JUNO experiment

26,000 3-inch photomultiplier tubes (PMTs) have been produced for Jiangmen Underground Neutrino Observatory (JUNO) by the Hainan Zhanchuang Photonics Technology Co., Ltd (HZC) company in China and passed all acceptance tests with only 15 tubes rejected. The mass production began in 2018 and elapsed for about 2 years at a rate of $\sim$1,000~PMTs per month. The characterization of the PMTs was performed in the factory concurrently with production as a joint effort between HZC and JUNO. Fifteen performance parameters were tracked at different sampling rates, and novel working strategies were implemented to improve quality assurance. This constitutes the largest sample of 3-inch PMTs ever produced and studied in detail to date.

physics.ins-det↗

arXiv2017

Commissioning of te China-ADS injector-I testing facility

The 10 MeV accelerator-driven subcritical system (ADS) Injector-I test stand at Institute of High Energy Physics (IHEP) is a testing facility dedicated to demonstrate one of the two injector design schemes [Injector Scheme-I, which works at 325 MHz], for the ADS project in China. The Injector adopted a four vane copper structure RFQ with output energy of 3.2 MeV and a superconducting (SC) section accommodating fourteen \b{eta}g=0.12 single spoke cavities, fourteen SC solenoids and fourteen cold BPMs. The ion source was installed since April of 2014, periods of commissioning are regularly scheduled between installation phases of the rest of the injector. Continuous wave (CW) beam was shooting through the injector and 10 MeV CW proton beam with average beam current around 2 mA was obtained recently. This contribution describe the results achieved so far and the difficulties encountered in CW commissioning.

physics.acc-ph↗