arXiv subjects

Yue-Kun Heng

Publications and source records attributed to Yue-Kun Heng.

6 recordsLinked to original sources

arXiv2024

Design & Optimization of the HV divider for JUNO 20-inch PMT

The Jiangmen Underground Observatory (JUNO) is a 20-kton liquid scintillator detector that employs 20,000 20-inch photomultiplier tubes (PMTs) as photon sensors, with 5,000 dynode-PMTs from HAMAMATSU Photonics K.K. (HPK), and 15,000 MCP-PMTs from North Night Vision Technology (NNVT) installed in pure water. JUNO aims to provide long-lasting and the best performance operation by utilizing a high-transparency liquid scintillator, high detection efficiency PMTs, and specially designed electronics including water-proof potting for the high voltage (HV) dividers of PMTs. In this paper, we present a summary of the design and optimization of HV dividers for both types of 20-inch PMTs, which includes collection efficiency, charge resolution, HV divider current, pulse shape, and maximum amplitude restriction. We have developed and finalized four schemes of the HV divider for different scenarios, including the final version selected by JUNO. All 20,000 20-inch PMTs have successfully undergone production and burning tests.

physics.ins-det↗

arXiv2024

Design and Experimental Application of a Radon Diffusion Chamber for Determining Diffusion Coefficients in Membrane Materials

In recent years, the issue of radon emanation and diffusion has become a critical concern for rare decay experiments, such as JUNO and PandaX-4T. This paper introduces a detector design featuring a symmetric radon detector cavity for the quantitative assessment of membrane materials' radon blocking capabilities. The performance of this design is evaluated through the application of Fick's Law and the diffusion equation considering material solubility. Our detector has completed measurements of radon diffusion coefficients for four types of membrane materials currently used in experiments, which also confirms the rationality of this detector design. The findings are instrumental in guiding the selection and evaluation of optimal materials for radon shielding to reduce radon background, contributing to boost sensitivities of rare event research.

physics.ins-det↗

arXiv2019

A quantitative approach to select PMTs for large detectors

Photomultiplier tubes (PMTs) are widely used in neutrino and other experiments for the detection of weak light. To date PMTs are the most sensitive single photon detector per unit area. In addition to the quantum efficiency for photon detection, there are a number of other specifications, such as rate and amplitude of after-pulses, dark noise rate, transit time spread, radioactive background of glass, peak-to-valley ratio, etc. All affect the photon detection and hence the physics goals. In addition, cost is another major factor for large experiments. It is important to know how to properly take into account all these parameters and choose the most appropriate PMTs. In this paper, we present an approach to quantify the impact of all parameters on the physics goals, including cost and risk. This method has been successfully used in the JUNO experiment. It can be applied to other experiments with large number of PMTs.

physics.ins-det↗

arXiv2017

A study of aging effects of barrel Time-Of-Flight system in the BESIII experiment

The Time-Of-Flight system consisting of plastic scintillation counters plays an important role for particle identification in the BESIII experiment at the BEPCII double ring $e^+e^-$ collider. Degradation of the detection efficiency of the barrel TOF system has been observed since the start of physical data taking and this effect has triggered intensive and systematic studies about aging effects of the detector. The aging rates of the attenuation lengths and relative gains are obtained based on the data acquired in past several years. This study is essential for ensuring an extended operation of the barrel TOF system in optimal conditions.

physics.ins-det↗

arXiv2016

Evaluation of new large area PMT with high quantum efficiency

The neutrino detector of the Jiangmen Underground Neutrino Observatory (JUNO) is designed to use 20 kilotons of liquid scintillator and approximately 16,000 20-inch photomultipliers (PMTs).One of the options is to use the 20-inch R12860 PMT with high quantum efficiency which has recently been developed by Hamamatsu Photonics. The performance of the newly developed PMT preproduction samples is evaluated. The results show that its quantum efficiency is $30\%$ at $400 nm$. Its Peak/Valley (P/V) ratio for the single photoelectron is 4.75 and the dark count rate is $27 kHz$ at the threshold of 3 mV while the gain is at $1 \times 10^7$. The transit time spread of a single photoelectron is $2.86 ns$. Generally the performances of this new 20-inch PMT are improved over the old one of R3600.

physics.ins-det↗

arXiv2015

The study of the aging behavior on large area MCP-PMT

Aging experiments of a novel type of large area MCP-PMT made by JUNO collaboration were conducted.In these aging experiments, the multi-photoelectron spectrum and single photoelectron spectrum were measured daily,as well as the MCP resistance of the second PMT before and after the experiment. Two PMTs were aged successivelyfor cross check. The first PMT was aged for 52 days, while the other one was aged for 84 days. In order to study the mechanism of the aging process, the high voltage on the second PMT was increased to accelerate its aging process when the cumulative output of charge from its anode was about 4 C. From our study, it can be known that large area MCP-PMT aging had a strong relationship with the related MCPs. In accordance with the PMT aging curve,a PMT aging model was setup and a general aging formula was given.

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