PMT calibration for the JSNS^2-II far detector with an embedded LED system

Abstract The JSNS^2-II (the second phase of JSNS^2, J-PARC Sterile Neutrino Search at J-PARC Spallation Neutron Source) is an experiment aimed at searching for sterile neutrinos. This experiment has entered its second phase, employing two liquid scintillator detectors located at near and far positions from the neutrino source. Recently, the far detector of the experiment has been completed and is currently in the calibration phase. The following properties of all functioning Photo-Multiplier-Tubes (PMTs) to detect the neutrino events in the far detector have been calibrated: PMT gain, its dependence of supplied High Voltage (HV), Peak-to-Valley (PV), and signal timing. This paper presents a detailed description of the calibration process utilizing the LED system. The LED system of the far detector uses two Ultra-Violet (UV) LEDs, which are effective in calibrating all of the PMTs at once. The UV light is converted into the visible light wavelengths inside liquid scintillator via the wavelength shifters, providing pseudo-isotropic light. To achieve a good energy resolution for physics events, a relative gain adjustment of up to 10% is required for all functioning PMTs. This will be achieved using the HV curves measured and the results of the LED calibration. The Peak-to-Valley (PV) ratio values, which distinguish the single photo-electron signal from the pedestal, are similar to those from the production company. Additionally, the precision of the PMT signal timing is measured to be 2.1 ns. This meets the event reconstruction requirement of 10 ns.

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Publication Details

Journal
Journal of Instrumentation
Published
2025-10-01
DOI
https://doi.org/10.1088/1748-0221/20/10/t10003
Primary Topic
Particle physics theoretical and experimental studies
Type
article
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article

PMT calibration for the JSNS^2-II far detector with an embedded LED system

Tomoyuki Maruyama, M. Yeh, R. Wang, Shinichi Sakamoto et al.
Journal of Instrumentation
Particle physics theoretical and experimental studies
article

PMT calibration for the JSNS^2-II far detector with an embedded LED system

Tomoyuki Maruyama, M. Yeh, R. Wang, Shinichi Sakamoto, J. Spitz, Kentaro Suzuya, Sang Youn Kim, Ji-Young Choi, R.G. Park, Myung-Ki Cheoun, E. M. Kim, T. Iida, Wen‐Jyi Hwang, Byung‐Joo Park, J.S. Park, Sin Kyu Kang, T. Dodo, F. Suekane, Manae Harada, Junhee Ryu, E. J. Kim, Takayuki Shima, Y. Takeuchi, M. Y. Pac, C. Rott, S. Masuda, S. J. M. Peeters, I. Yu, K. K. Joo, J.B. Park, T. Nakano, H.W. Park, T. Kawasaki, Shin-ichiro Meigo, T. Konno, Kenichi Sakai, Y. Kasugai, Wei Qiang Wang, Ji Soo Park, Yuji Yamaguchi, E. Marzec, Jinhyeok Jang, D. H. Lee, J. H. Choi, J. Goh, H. I. Jang, S. Hasegawa, D. H. Moon, Y. Sugaya, K. Nishikawa, M. Niiyama, C. Little, C. D. Shin, Hirotsugu Kinoshita, D. E. Jung, S. B. Kim, I. S. Yeo
article en

Abstract

Abstract The JSNS^2-II (the second phase of JSNS^2, J-PARC Sterile Neutrino Search at J-PARC Spallation Neutron Source) is an experiment aimed at searching for sterile neutrinos. This experiment has entered its second phase, employing two liquid scintillator detectors located at near and far positions from the neutrino source. Recently, the far detector of the experiment has been completed and is currently in the calibration phase. The following properties of all functioning Photo-Multiplier-Tubes (PMTs) to detect the neutrino events in the far detector have been calibrated: PMT gain, its dependence of supplied High Voltage (HV), Peak-to-Valley (PV), and signal timing. This paper presents a detailed description of the calibration process utilizing the LED system. The LED system of the far detector uses two Ultra-Violet (UV) LEDs, which are effective in calibrating all of the PMTs at once. The UV light is converted into the visible light wavelengths inside liquid scintillator via the wavelength shifters, providing pseudo-isotropic light. To achieve a good energy resolution for physics events, a relative gain adjustment of up to 10% is required for all functioning PMTs. This will be achieved using the HV curves measured and the results of the LED calibration. The Peak-to-Valley (PV) ratio values, which distinguish the single photo-electron signal from the pedestal, are similar to those from the production company. Additionally, the precision of the PMT signal timing is measured to be 2.1 ns. This meets the event reconstruction requirement of 10 ns.

Journal of InstrumentationVol. 20(10)
Chonnam National University (KR), Japan Atomic Energy Agency (JP), Seoul National University of Science and Technology (KR), High Energy Accelerator Research Organization (JP), Soongsil University (KR), University of Tsukuba (JP), Sun Yat-sen University (CN), Dongshin University (KR), University of Sussex (GB), Kyoto Sangyo University (JP), Jeonju National University of Education (KR), Brookhaven National Laboratory (US), Tohoku University (JP), University of Utah (US), University of Michigan (US), Japan Proton Accelerator Research Complex (JP), Kyungpook National University (KR), Kyung Hee University (KR), Gwangju Institute of Science and Technology (KR), Seoyeong University (KR), Advanced Science Research Center (JP), Kitasato University (JP), Jeonbuk National University (KR), Sungkyunkwan University (KR), Michigan State University (US), The University of Osaka (JP)
Openalex Percentile: Top 87%
Particle physics theoretical and experimental studies
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