arXiv subjects

Narongkiat Rodphai

Publications and source records attributed to Narongkiat Rodphai.

4 recordsLinked to original sources

arXiv2025

JUNO 20-inch PMT and electronics system characterization using large pulses of PMT dark counts at the Pan-Asia testing platform

The main goal of the JUNO experiment is to determine the neutrino mass ordering with a 20kt liquid-scintillator detector. The 20-inch PMT and its 1F3 (one for three) electronics are crucial to realize the excellent energy resolution of at least 3% at 1MeV. The knowledge on the PMT and 1F3 electronics response is critical for detector performance understanding. A study of the JUNO 20-inch PMT and 1F3 electronics system characterization is presented using large pulses of PMT dark count at the Pan-Asia testing platform in China. Thanks to its broad amplitude range and high rate, the large pulse signals are also used to investigate the PMT after pulse response.

physics.ins-det↗

arXiv2025

Dark Count Rate Stability of JUNO 20-inch PMTs in Mass Testing

The Jiangmen Underground Neutrino Observatory (JUNO) is an ambitious multipurpose neutrino experiment designed to determine the neutrino mass ordering, with an impressive energy resolution goal of at least 3% at 1 MeV. To achieve a photon detection coverage of approximately 75%, JUNO will utilize two types of 20-inch photomultiplier tubes (PMTs): the large PMT (LPMT) and the microchannel plate PMT (MCP-PMT). A significant concern in high-precision neutrino measurements is the dark count rate (DCR) of PMTs, which introduces noise that can adversely affect energy measurement accuracy. During the mass testing phase of the JUNO 20-inch PMTs, comprehensive measurements of the DCR were undertaken. These measurements not only captured the DCR values of individual PMTs but also examined the stability and temperature dependence of the DCR at an operating gain of (1x10^7). This paper presents a detailed characterization of the DCR of the JUNO 20-inch PMTs, investigating factors such as cooling time, temperature variations, and long-term stability using the JUNO Pan-Asia PMT testing facilities. The results reveal distinct DCR characteristics between the two types of PMTs, providing valuable insights into the nature of DCR and its implications for JUNO's scientific objectives. In addition to performance characterization, we implemented a monitoring system to track DCR stability over time. Notably, several spikes in DCR were identified, prompting a preliminary investigation into their causes. Potential factors contributing to these spikes, such as flasher events, were explored using coincidence rate analysis and complementary imaging techniques. The findings from this study are crucial for optimizing the performance of PMTs in JUNO, ultimately aiding the experiment in achieving its goals related to neutrino physics.

physics.ins-det↗

arXiv2024

Design and Integration of JUNO-OSIRIS

The Jiangmen Underground Neutrino Observatory (JUNO) is a neutrino detection experiment characterized by an acrylic sphere, measuring 35.4 m in diameter, containing 20,000 tons of liquid scintillator. This sphere is encompassed by as many as 17,600 photomultiplier tubes (PMTs) with a 20-inch diameter, achieving an overall coverage of 77.9%. With these impressive capabilities, the JUNO experiment aims to achieve an exceptional effective energy resolution of 3% at 1 MeV. The Online Scintillator Internal Radioactivity Investigation System (OSIRIS) serves as a precursor detector, around 100 m aside in horizontal of the site of the JUNO detector underground, tasked with monitoring and examining the purity of the liquid scintillator prior to its transfer to the JUNO central detector. The OSIRIS, also as a pre-detector of JUNO, is constructed with a cylindrical acrylic vessel designed to hold 18 tons of liquid scintillator. It is situated within a 9-m height cylindrical tank filled with 550 tons of pure water. This detector was specifically engineered to search for the fast coincidence decays of $^{214}$Bi -$^{214}$Po and $^{212}$Bi -$^{212}$Po in the decay chains of $^{238}$U and $^{232}$Th, respectively.OSIRIS has been designed to reach a sensitivity of 10$^{-16}$ g/g for U/Th to test scintillator radiopurity to the level required for the detection of solar neutrinos. Additionally, 64 20-inch microchannel plate PMTs (MCP PMTs) were positioned around the liquid scintillator vessel to observe incoming interactions, along with an additional 12 20-inch MCP PMTs for the water Cherenkov muon veto system. The OSIRIS pre-detector has been fully constructed and integrated, providing a plenty of preliminary results from the air runs. The next step in the process involves commencing the filling soon, aiming to involve an in-depth examination of the impurities within the liquid scintillator.

physics.ins-det↗

arXiv2024

Dark Count of 20-inch PMTs Generated by Natural Radioactivity

The primary objective of the JUNO experiment is to determine the ordering of neutrino masses using a 20-kton liquid-scintillator detector. The 20-inch photomultiplier tube (PMT) plays a crucial role in achieving excellent energy resolution of at least 3% at 1 MeV. Understanding the characteristics and features of the PMT is vital for comprehending the detector's performance, particularly regarding the occurrence of large pulses in PMT dark counts. This research paper aims to further investigate the origin of these large pulses in the 20-inch PMT dark count rate through measurements and simulations. The findings confirm that the main sources of the large pulses are natural radioactivity and muons striking the PMT glass. By analyzing the PMT dark count rate spectrum, it becomes possible to roughly estimate the radioactivity levels in the surrounding environment.

physics.ins-det↗