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Embedded underwater front-end electronics for the 3-inch photomultipliers in the JUNO experiment

Fuente: arXiv

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Bibliographische Detailangaben
Hauptverfasser:	Cerna, Cedric, He, Miao, Jiang, Xiaoshan, Ochoa-Ricoux, Juan Pedro, Perrot, Frederic, Abusleme, Angel, Adam, Thomas, An, Fengpeng, Andreopoulos, Costas, Andronico, Giuseppe, de Andre, Joao Pedro Athayde Marcondes, Anfimov, Nikolay, Antonelli, Vito, Antoshkina, Tatiana, Auguste, Didier, Balashov, Nikita, Barresi, Andrea, Basilico, Davide, Baussan, Eric, Beretta, Marco, Bergnoli, Antonio, Biktemerova, Svetlana, Birkenfeld, Thilo, Blyth, Simon, Boehles, Manuel, Bolshakova, Anastasia, Bongrand, Mathieu, Bordereau, Clement, Borghesi, Matteo, Breton, Dominique, Brigatti, Augusto, Brugnera, Riccardo, Bruno, Riccardo, Budano, Antonio, Busto, Jose, Buchner, Marcel, Cabrera, Anatael, Caccianiga, Barbara, Cai, Hao, Cai, Xiao, Cai, Yi-zhou, Callier, Stephane, Cammi, Antonio, Campeny, Augustin, Cao, Guofu, Cao, Jun, Cao, Yaoqi, Caruso, Rossella, Giudice, Nunzio, Gonchar, Maxim, Gong, Guanda, Gong, Guanghua, Gornushkin, Yuri, Grassi, Marco, Gromov, Maxim, Gromov, Vasily, Gu, Minhao, Gu, Xiaofei, Gu, Yu, Guan, Mengyun, Guan, Yuduo, Guardone, Nunzio, Guizzetti, Rosa Maria, Guo, Cong, Guo, Wanlei, Hagner, Caren, Han, Hechong, Han, Yang, Hao, Chuanhui, Hariharan, Vidhya Thara, He, Wei, He, Xinhai, Heinz, Tobias, Hellmuth, Patrick, Heng, Yuekun, Herrera, Rafael, Hor, YuenKeung, Hou, Shaojing, Houria, Fatima, Claverie, Gerard, Clementi, Catia, Clerbaux, Barbara, Coletta, Claudio, Chiesa, Davide, Chimenti, Pietro, Chu, Ziliang, Chukanov, Artem, Molla, Marta Colomer, Mantovani, Fabio, Mari, Stefano M., Martini, Agnese, Martyn, Johann, Mayer, Matthias, Mayilyan, Davit, Meng, Yue, Meregaglia, Anselmo, Miramonti, Lino, Montuschi, Michele, Morton-Blake, Iwan, Mu, Xiangyi, Murgod, Lakshmi, Nastasi, Massimiliano, Naumov, Dmitry V., Naumova, Elena, Nemchenok, Igor, Neuerburg, Elisabeth, Nikolaev, Alexey, Ning, Feipeng, Ning, Zhe, Niu, Yujie, Nunokawa, Hiroshi, Oberauer, Lothar, Olivares, Sebastian, Olshevskiy, Alexander, Orestano, Domizia, Ortica, Fausto, Othegraven, Rainer, Pan, Yifei, Paoloni, Alessandro, Parker, George, Pei, Yatian, Pelicci, Luca, Peng, Anguo, Peng, Yu, Peng, Zhaoyuan, Percalli, Elisa, Perrin, Willy, Petrucci, Fabrizio, Pilarczyk, Oliver, Popov, Artyom, Poussot, Pascal, Previtali, Ezio, Qi, Fazhi, Qi, Ming, Qian, Sen, Qian, Xiaohui, Wu, Zhaoxiang, Wu, Zhi, Wurm, Michael, Wurtz, Jacques, Xia, Dongmei, Xian, Shishen, Xiang, Ziqian, Xiao, Fei, Xiao, Pengfei, Xiao, Tianying, Xiao, Xiang, Xie, Wei-Jun, Xie, Xiaochuan, Xie, Yuguang, Xing, Zhizhong, Xu, Benda, Xu, Cheng, Xu, Chuang, Xu, Donglian, Xu, Fanrong, Xu, Jiayang, Xu, Jilei, Xu, Jinghuan, Xu, Meihang, Xu, Shiwen, Xu, Xunjie, Xue, Dongyang, Xue, Jingqin, Yan, Baojun, Yan, Qiyu, Yan, Taylor, Yan, Xiongbo, Yang, Changgen, Yang, Chengfeng, Yang, Fengfan, Yang, Jie, Yang, Kaiwei, Yang, Lei, Yang, Pengfei, Yang, Xiaoyu, Yang, Xuhui, Yang, Zekun, Yao, Haifeng, Ye, Jiaxuan, Ye, Mei, Ye, Ziping, Yermia, Frederic, Yin, Jilong, Yin, Weiqing, Yin, Xiaohao, You, Zhengyun, Yu, Boxiang, Yu, Chiye, Yu, Chunxu, Yu, Hongzhao, Yu, Peidong, Yu, Simi, Yu, Zeyuan, Yuan, Cenxi, Zafar, Noman, Zamora, Jilberto, Zavadskyi, Vitalii, Zeng, Fanrui, Zeng, Shan, Zeng, Tingxuan, Zhan, Liang, Zhang, Bin, Zhang, Feiyang, Zhang, Han, Zhang, Hangchang, Zhang, Haosen, Zhang, Honghao, Zhang, Jiawen, Zhang, Jie, Zhang, Jingbo, Zhang, Junwei, Zhang, Lei, Zhang, Ping, Zhang, Qingmin, Zhang, Rongping, Zhang, Shiqi, Zhang, Shuihan, Zhang, Tao, Zhang, Xiaomei, Zhang, Xu, Zhang, Xuantong, Zhang, Yibing, Zhang, Yinhong, Zhang, Yiyu, Zhang, Yongpeng, Zhang, Yuanyuan, Zhang, Yumei, Zhang, Zhicheng, Zhang, Zhijian, Zhao, Jie, Zhao, Runze, Zhao, Shujun, Zheng, Yangheng, Zhou, Li, Zhou, Shun, Zhou, Xiang, Zhou, Xing, Zhu, Jingsen, Zhu, Kangfu, Zhu, Kejun, Zhuang, Bo, Zhuang, Honglin, Zou, Jiaheng
Format:	Preprint
Veröffentlicht:	2026
Schlagworte:	Instrumentation and Detectors High Energy Physics - Experiment
Online-Zugang:	Acceder al recurso
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_version_	1866913069739802624
author	Cerna, Cedric He, Miao Jiang, Xiaoshan Ochoa-Ricoux, Juan Pedro Perrot, Frederic Abusleme, Angel Adam, Thomas An, Fengpeng Andreopoulos, Costas Andronico, Giuseppe de Andre, Joao Pedro Athayde Marcondes Anfimov, Nikolay Antonelli, Vito Antoshkina, Tatiana Auguste, Didier Balashov, Nikita Barresi, Andrea Basilico, Davide Baussan, Eric Beretta, Marco Bergnoli, Antonio Biktemerova, Svetlana Birkenfeld, Thilo Blyth, Simon Boehles, Manuel Bolshakova, Anastasia Bongrand, Mathieu Bordereau, Clement Borghesi, Matteo Breton, Dominique Brigatti, Augusto Brugnera, Riccardo Bruno, Riccardo Budano, Antonio Busto, Jose Buchner, Marcel Cabrera, Anatael Caccianiga, Barbara Cai, Hao Cai, Xiao Cai, Yi-zhou Callier, Stephane Cammi, Antonio Campeny, Augustin Cao, Guofu Cao, Jun Cao, Yaoqi Caruso, Rossella Giudice, Nunzio Gonchar, Maxim Gong, Guanda Gong, Guanghua Gornushkin, Yuri Grassi, Marco Gromov, Maxim Gromov, Vasily Gu, Minhao Gu, Xiaofei Gu, Yu Guan, Mengyun Guan, Yuduo Guardone, Nunzio Guizzetti, Rosa Maria Guo, Cong Guo, Wanlei Hagner, Caren Han, Hechong Han, Yang Hao, Chuanhui Hariharan, Vidhya Thara He, Wei He, Xinhai Heinz, Tobias Hellmuth, Patrick Heng, Yuekun Herrera, Rafael Hor, YuenKeung Hou, Shaojing Houria, Fatima Claverie, Gerard Clementi, Catia Clerbaux, Barbara Coletta, Claudio Chiesa, Davide Chimenti, Pietro Chu, Ziliang Chukanov, Artem Molla, Marta Colomer Mantovani, Fabio Mari, Stefano M. Martini, Agnese Martyn, Johann Mayer, Matthias Mayilyan, Davit Meng, Yue Meregaglia, Anselmo Miramonti, Lino Montuschi, Michele Morton-Blake, Iwan Mu, Xiangyi Murgod, Lakshmi Nastasi, Massimiliano Naumov, Dmitry V. Naumova, Elena Nemchenok, Igor Neuerburg, Elisabeth Nikolaev, Alexey Ning, Feipeng Ning, Zhe Niu, Yujie Nunokawa, Hiroshi Oberauer, Lothar Olivares, Sebastian Olshevskiy, Alexander Orestano, Domizia Ortica, Fausto Othegraven, Rainer Pan, Yifei Paoloni, Alessandro Parker, George Pei, Yatian Pelicci, Luca Peng, Anguo Peng, Yu Peng, Zhaoyuan Percalli, Elisa Perrin, Willy Petrucci, Fabrizio Pilarczyk, Oliver Popov, Artyom Poussot, Pascal Previtali, Ezio Qi, Fazhi Qi, Ming Qian, Sen Qian, Xiaohui Wu, Zhaoxiang Wu, Zhi Wurm, Michael Wurtz, Jacques Xia, Dongmei Xian, Shishen Xiang, Ziqian Xiao, Fei Xiao, Pengfei Xiao, Tianying Xiao, Xiang Xie, Wei-Jun Xie, Xiaochuan Xie, Yuguang Xing, Zhizhong Xu, Benda Xu, Cheng Xu, Chuang Xu, Donglian Xu, Fanrong Xu, Jiayang Xu, Jilei Xu, Jinghuan Xu, Meihang Xu, Shiwen Xu, Xunjie Xue, Dongyang Xue, Jingqin Yan, Baojun Yan, Qiyu Yan, Taylor Yan, Xiongbo Yang, Changgen Yang, Chengfeng Yang, Fengfan Yang, Jie Yang, Kaiwei Yang, Lei Yang, Pengfei Yang, Xiaoyu Yang, Xuhui Yang, Zekun Yao, Haifeng Ye, Jiaxuan Ye, Mei Ye, Ziping Yermia, Frederic Yin, Jilong Yin, Weiqing Yin, Xiaohao You, Zhengyun Yu, Boxiang Yu, Chiye Yu, Chunxu Yu, Hongzhao Yu, Peidong Yu, Simi Yu, Zeyuan Yuan, Cenxi Zafar, Noman Zamora, Jilberto Zavadskyi, Vitalii Zeng, Fanrui Zeng, Shan Zeng, Tingxuan Zhan, Liang Zhang, Bin Zhang, Feiyang Zhang, Han Zhang, Hangchang Zhang, Haosen Zhang, Honghao Zhang, Jiawen Zhang, Jie Zhang, Jingbo Zhang, Junwei Zhang, Lei Zhang, Ping Zhang, Qingmin Zhang, Rongping Zhang, Shiqi Zhang, Shuihan Zhang, Tao Zhang, Xiaomei Zhang, Xu Zhang, Xuantong Zhang, Yibing Zhang, Yinhong Zhang, Yiyu Zhang, Yongpeng Zhang, Yuanyuan Zhang, Yumei Zhang, Zhicheng Zhang, Zhijian Zhao, Jie Zhao, Runze Zhao, Shujun Zheng, Yangheng Zhou, Li Zhou, Shun Zhou, Xiang Zhou, Xing Zhu, Jingsen Zhu, Kangfu Zhu, Kejun Zhuang, Bo Zhuang, Honglin Zou, Jiaheng
author_facet	Cerna, Cedric He, Miao Jiang, Xiaoshan Ochoa-Ricoux, Juan Pedro Perrot, Frederic Abusleme, Angel Adam, Thomas An, Fengpeng Andreopoulos, Costas Andronico, Giuseppe de Andre, Joao Pedro Athayde Marcondes Anfimov, Nikolay Antonelli, Vito Antoshkina, Tatiana Auguste, Didier Balashov, Nikita Barresi, Andrea Basilico, Davide Baussan, Eric Beretta, Marco Bergnoli, Antonio Biktemerova, Svetlana Birkenfeld, Thilo Blyth, Simon Boehles, Manuel Bolshakova, Anastasia Bongrand, Mathieu Bordereau, Clement Borghesi, Matteo Breton, Dominique Brigatti, Augusto Brugnera, Riccardo Bruno, Riccardo Budano, Antonio Busto, Jose Buchner, Marcel Cabrera, Anatael Caccianiga, Barbara Cai, Hao Cai, Xiao Cai, Yi-zhou Callier, Stephane Cammi, Antonio Campeny, Augustin Cao, Guofu Cao, Jun Cao, Yaoqi Caruso, Rossella Giudice, Nunzio Gonchar, Maxim Gong, Guanda Gong, Guanghua Gornushkin, Yuri Grassi, Marco Gromov, Maxim Gromov, Vasily Gu, Minhao Gu, Xiaofei Gu, Yu Guan, Mengyun Guan, Yuduo Guardone, Nunzio Guizzetti, Rosa Maria Guo, Cong Guo, Wanlei Hagner, Caren Han, Hechong Han, Yang Hao, Chuanhui Hariharan, Vidhya Thara He, Wei He, Xinhai Heinz, Tobias Hellmuth, Patrick Heng, Yuekun Herrera, Rafael Hor, YuenKeung Hou, Shaojing Houria, Fatima Claverie, Gerard Clementi, Catia Clerbaux, Barbara Coletta, Claudio Chiesa, Davide Chimenti, Pietro Chu, Ziliang Chukanov, Artem Molla, Marta Colomer Mantovani, Fabio Mari, Stefano M. Martini, Agnese Martyn, Johann Mayer, Matthias Mayilyan, Davit Meng, Yue Meregaglia, Anselmo Miramonti, Lino Montuschi, Michele Morton-Blake, Iwan Mu, Xiangyi Murgod, Lakshmi Nastasi, Massimiliano Naumov, Dmitry V. Naumova, Elena Nemchenok, Igor Neuerburg, Elisabeth Nikolaev, Alexey Ning, Feipeng Ning, Zhe Niu, Yujie Nunokawa, Hiroshi Oberauer, Lothar Olivares, Sebastian Olshevskiy, Alexander Orestano, Domizia Ortica, Fausto Othegraven, Rainer Pan, Yifei Paoloni, Alessandro Parker, George Pei, Yatian Pelicci, Luca Peng, Anguo Peng, Yu Peng, Zhaoyuan Percalli, Elisa Perrin, Willy Petrucci, Fabrizio Pilarczyk, Oliver Popov, Artyom Poussot, Pascal Previtali, Ezio Qi, Fazhi Qi, Ming Qian, Sen Qian, Xiaohui Wu, Zhaoxiang Wu, Zhi Wurm, Michael Wurtz, Jacques Xia, Dongmei Xian, Shishen Xiang, Ziqian Xiao, Fei Xiao, Pengfei Xiao, Tianying Xiao, Xiang Xie, Wei-Jun Xie, Xiaochuan Xie, Yuguang Xing, Zhizhong Xu, Benda Xu, Cheng Xu, Chuang Xu, Donglian Xu, Fanrong Xu, Jiayang Xu, Jilei Xu, Jinghuan Xu, Meihang Xu, Shiwen Xu, Xunjie Xue, Dongyang Xue, Jingqin Yan, Baojun Yan, Qiyu Yan, Taylor Yan, Xiongbo Yang, Changgen Yang, Chengfeng Yang, Fengfan Yang, Jie Yang, Kaiwei Yang, Lei Yang, Pengfei Yang, Xiaoyu Yang, Xuhui Yang, Zekun Yao, Haifeng Ye, Jiaxuan Ye, Mei Ye, Ziping Yermia, Frederic Yin, Jilong Yin, Weiqing Yin, Xiaohao You, Zhengyun Yu, Boxiang Yu, Chiye Yu, Chunxu Yu, Hongzhao Yu, Peidong Yu, Simi Yu, Zeyuan Yuan, Cenxi Zafar, Noman Zamora, Jilberto Zavadskyi, Vitalii Zeng, Fanrui Zeng, Shan Zeng, Tingxuan Zhan, Liang Zhang, Bin Zhang, Feiyang Zhang, Han Zhang, Hangchang Zhang, Haosen Zhang, Honghao Zhang, Jiawen Zhang, Jie Zhang, Jingbo Zhang, Junwei Zhang, Lei Zhang, Ping Zhang, Qingmin Zhang, Rongping Zhang, Shiqi Zhang, Shuihan Zhang, Tao Zhang, Xiaomei Zhang, Xu Zhang, Xuantong Zhang, Yibing Zhang, Yinhong Zhang, Yiyu Zhang, Yongpeng Zhang, Yuanyuan Zhang, Yumei Zhang, Zhicheng Zhang, Zhijian Zhao, Jie Zhao, Runze Zhao, Shujun Zheng, Yangheng Zhou, Li Zhou, Shun Zhou, Xiang Zhou, Xing Zhu, Jingsen Zhu, Kangfu Zhu, Kejun Zhuang, Bo Zhuang, Honglin Zou, Jiaheng
contents	The Jiangmen Underground Neutrino Observatory (JUNO) is a 20-kton liquid scintillator-based, low-radioactivity, multi-purpose neutrino detector located 693 meters (1800 m.w.e.) underground in the Guangdong province, China. To detect scintillation light produced in the target, the detector is equipped with 17,612 20-inch photomultipliers (PMTs), forming the Large PMT system (LPMT). In addition, 25,600 3-inch photomultipliers (the Small Photomultiplier System or SPMT) are deployed in the gaps between the LPMTs. This paper presents the design and performance of the underwater front-end electronics developed for the SPMT system. It details the individual electronics boards and their key components, the inter-board interfaces, the system-level design, and the firmware architecture that supports data acquisition and control. It also outlines mechanical and thermal integration, board validation procedures, and system performance metrics. The readout chain includes digitization of 128 PMT channels per unit, synchronized time-stamping, charge measurement, event packaging, and bandwidth management. Comprehensive validation confirms the system's readiness to meet JUNO's stringent physics goals. The underwater electronics achieve noise levels as low as 0.04 photoelectrons with minimal crosstalk (below 0.4%) and a bandwidth of 57 MB/s, ensuring reliable single photo-electron detection and operation under high-rate conditions. The SPMT system has now been fully integrated and installed in JUNO. Its commissioning and physics performance will be reported in a future publication.
format	Preprint
id	arxiv_https___arxiv_org_abs_2604_25835
institution	arXiv
publishDate	2026
record_format	arxiv
spellingShingle	Embedded underwater front-end electronics for the 3-inch photomultipliers in the JUNO experiment Cerna, Cedric He, Miao Jiang, Xiaoshan Ochoa-Ricoux, Juan Pedro Perrot, Frederic Abusleme, Angel Adam, Thomas An, Fengpeng Andreopoulos, Costas Andronico, Giuseppe de Andre, Joao Pedro Athayde Marcondes Anfimov, Nikolay Antonelli, Vito Antoshkina, Tatiana Auguste, Didier Balashov, Nikita Barresi, Andrea Basilico, Davide Baussan, Eric Beretta, Marco Bergnoli, Antonio Biktemerova, Svetlana Birkenfeld, Thilo Blyth, Simon Boehles, Manuel Bolshakova, Anastasia Bongrand, Mathieu Bordereau, Clement Borghesi, Matteo Breton, Dominique Brigatti, Augusto Brugnera, Riccardo Bruno, Riccardo Budano, Antonio Busto, Jose Buchner, Marcel Cabrera, Anatael Caccianiga, Barbara Cai, Hao Cai, Xiao Cai, Yi-zhou Callier, Stephane Cammi, Antonio Campeny, Augustin Cao, Guofu Cao, Jun Cao, Yaoqi Caruso, Rossella Giudice, Nunzio Gonchar, Maxim Gong, Guanda Gong, Guanghua Gornushkin, Yuri Grassi, Marco Gromov, Maxim Gromov, Vasily Gu, Minhao Gu, Xiaofei Gu, Yu Guan, Mengyun Guan, Yuduo Guardone, Nunzio Guizzetti, Rosa Maria Guo, Cong Guo, Wanlei Hagner, Caren Han, Hechong Han, Yang Hao, Chuanhui Hariharan, Vidhya Thara He, Wei He, Xinhai Heinz, Tobias Hellmuth, Patrick Heng, Yuekun Herrera, Rafael Hor, YuenKeung Hou, Shaojing Houria, Fatima Claverie, Gerard Clementi, Catia Clerbaux, Barbara Coletta, Claudio Chiesa, Davide Chimenti, Pietro Chu, Ziliang Chukanov, Artem Molla, Marta Colomer Mantovani, Fabio Mari, Stefano M. Martini, Agnese Martyn, Johann Mayer, Matthias Mayilyan, Davit Meng, Yue Meregaglia, Anselmo Miramonti, Lino Montuschi, Michele Morton-Blake, Iwan Mu, Xiangyi Murgod, Lakshmi Nastasi, Massimiliano Naumov, Dmitry V. Naumova, Elena Nemchenok, Igor Neuerburg, Elisabeth Nikolaev, Alexey Ning, Feipeng Ning, Zhe Niu, Yujie Nunokawa, Hiroshi Oberauer, Lothar Olivares, Sebastian Olshevskiy, Alexander Orestano, Domizia Ortica, Fausto Othegraven, Rainer Pan, Yifei Paoloni, Alessandro Parker, George Pei, Yatian Pelicci, Luca Peng, Anguo Peng, Yu Peng, Zhaoyuan Percalli, Elisa Perrin, Willy Petrucci, Fabrizio Pilarczyk, Oliver Popov, Artyom Poussot, Pascal Previtali, Ezio Qi, Fazhi Qi, Ming Qian, Sen Qian, Xiaohui Wu, Zhaoxiang Wu, Zhi Wurm, Michael Wurtz, Jacques Xia, Dongmei Xian, Shishen Xiang, Ziqian Xiao, Fei Xiao, Pengfei Xiao, Tianying Xiao, Xiang Xie, Wei-Jun Xie, Xiaochuan Xie, Yuguang Xing, Zhizhong Xu, Benda Xu, Cheng Xu, Chuang Xu, Donglian Xu, Fanrong Xu, Jiayang Xu, Jilei Xu, Jinghuan Xu, Meihang Xu, Shiwen Xu, Xunjie Xue, Dongyang Xue, Jingqin Yan, Baojun Yan, Qiyu Yan, Taylor Yan, Xiongbo Yang, Changgen Yang, Chengfeng Yang, Fengfan Yang, Jie Yang, Kaiwei Yang, Lei Yang, Pengfei Yang, Xiaoyu Yang, Xuhui Yang, Zekun Yao, Haifeng Ye, Jiaxuan Ye, Mei Ye, Ziping Yermia, Frederic Yin, Jilong Yin, Weiqing Yin, Xiaohao You, Zhengyun Yu, Boxiang Yu, Chiye Yu, Chunxu Yu, Hongzhao Yu, Peidong Yu, Simi Yu, Zeyuan Yuan, Cenxi Zafar, Noman Zamora, Jilberto Zavadskyi, Vitalii Zeng, Fanrui Zeng, Shan Zeng, Tingxuan Zhan, Liang Zhang, Bin Zhang, Feiyang Zhang, Han Zhang, Hangchang Zhang, Haosen Zhang, Honghao Zhang, Jiawen Zhang, Jie Zhang, Jingbo Zhang, Junwei Zhang, Lei Zhang, Ping Zhang, Qingmin Zhang, Rongping Zhang, Shiqi Zhang, Shuihan Zhang, Tao Zhang, Xiaomei Zhang, Xu Zhang, Xuantong Zhang, Yibing Zhang, Yinhong Zhang, Yiyu Zhang, Yongpeng Zhang, Yuanyuan Zhang, Yumei Zhang, Zhicheng Zhang, Zhijian Zhao, Jie Zhao, Runze Zhao, Shujun Zheng, Yangheng Zhou, Li Zhou, Shun Zhou, Xiang Zhou, Xing Zhu, Jingsen Zhu, Kangfu Zhu, Kejun Zhuang, Bo Zhuang, Honglin Zou, Jiaheng Instrumentation and Detectors High Energy Physics - Experiment The Jiangmen Underground Neutrino Observatory (JUNO) is a 20-kton liquid scintillator-based, low-radioactivity, multi-purpose neutrino detector located 693 meters (1800 m.w.e.) underground in the Guangdong province, China. To detect scintillation light produced in the target, the detector is equipped with 17,612 20-inch photomultipliers (PMTs), forming the Large PMT system (LPMT). In addition, 25,600 3-inch photomultipliers (the Small Photomultiplier System or SPMT) are deployed in the gaps between the LPMTs. This paper presents the design and performance of the underwater front-end electronics developed for the SPMT system. It details the individual electronics boards and their key components, the inter-board interfaces, the system-level design, and the firmware architecture that supports data acquisition and control. It also outlines mechanical and thermal integration, board validation procedures, and system performance metrics. The readout chain includes digitization of 128 PMT channels per unit, synchronized time-stamping, charge measurement, event packaging, and bandwidth management. Comprehensive validation confirms the system's readiness to meet JUNO's stringent physics goals. The underwater electronics achieve noise levels as low as 0.04 photoelectrons with minimal crosstalk (below 0.4%) and a bandwidth of 57 MB/s, ensuring reliable single photo-electron detection and operation under high-rate conditions. The SPMT system has now been fully integrated and installed in JUNO. Its commissioning and physics performance will be reported in a future publication.
title	Embedded underwater front-end electronics for the 3-inch photomultipliers in the JUNO experiment
topic	Instrumentation and Detectors High Energy Physics - Experiment
url	https://arxiv.org/abs/2604.25835