The Jiangmen Underground Neutrino Observatory (JUNO) is a 20 kton liquid scintillator detector in a laboratory at 700-m underground. An excellent energy resolution and a large fiducial volume offer exciting opportunities for addressing many important topics in neutrino and astro-particle physics. With six years of data, the neutrino mass ordering can be determined at a 3–4$\sigma$ significance and the neutrino oscillation parameters ${sin}^2{\theta }_{12}$, $\Delta m_{21}^2$, and $\left|\Delta m_{32}^2\right|$ can be measured to a precision of 0.6% or better, by detecting reactor antineutrinos from the Taishan and Yangjiang nuclear power plants. With ten years of data, neutrinos from all past core-collapse supernovae could be observed at a 3$\sigma$ significance; a lower limit of the proton lifetime, $8.34\times 10^{33}$ years (90% C.L.), can be set by searching for $p\to \bar{\nu }{K}^{+}$; detection of solar neutrinos would shed new light on the solar metallicity problem and examine the vacuum-matter transition region. A typical core-collapse supernova at a distance of 10 kpc would lead to $\sim 5000$ inverse-beta-decay events and $\sim 2000$ (300) all-flavor neutrino–proton (electron) elastic scattering events in JUNO. Geo-neutrinos can be detected with a rate of $\sim 400$ events per year. Construction of the detector is very challenging. In this review, we summarize the final design of the JUNO detector and the key R&D achievements, following the Conceptual Design Report in 2015 (Djurcic et al., 2015). All 20-inch PMTs have been procured and tested. The average photon detection efficiency is 28.9% for the 15,000 MCP PMTs and 28.1% for the 5000 dynode PMTs, higher than the JUNO requirement of 27%. Together with the $>20$ m attenuation length of the liquid scintillator achieved in a 20-ton pilot purification test and the $>96\text{\%}$ transparency of the acrylic panel, we expect a yield of 1345 photoelectrons per MeV and an effective relative energy resolution of $3.02\text{\%}/\sqrt{E\mathrm{(MeV\; )}}$ in simulations (Abusleme et al., 2021). To maintain the high performance, the underwater electronics is designed to have a loss rate $<0.5\text{\%}$ in six years. With degassing membranes and a micro-bubble system, the radon concentration in the 35 kton water pool could be lowered to $<10$ mBq/m${}^3$. Acrylic panels of radiopurity $<0.5$ ppt U/Th for the 35.4-m diameter liquid scintillator vessel are produced with a dedicated production line. The 20 kton liquid scintillator will be purified onsite with Alumina filtration, distillation, water extraction, and gas stripping. Together with other low background handling, singles in the fiducial volume can be controlled to $\sim 10\mathrm{Hz}$. The JUNO experiment also features a double calorimeter system with 25,600 3-inch PMTs, a liquid scintillator testing facility OSIRIS, and a near detector TAO.

江门地下中微子观测站 (JUNO) 是一个 20 kton 液体闪烁体探测器，位于地下 700 米的实验室中。出色的能量分辨率和大的基准体积为解决中微子和天体粒子物理学中的许多重要主题提供了令人兴奋的机会。通过六年的数据，中微子质量排序可以确定为 3-4$\sigma$显着性和中微子振荡参数${罪}^2{\theta }_{12}$,$\Delta {米}_{21}^2$， 和$\left|\Delta {米}_{32}^2\right|$通过检测台山和阳江核电站的反应堆反中微子，可以测量到 0.6% 或更高的精度。通过十年的数据，所有过去核心坍缩超新星的中微子都可以在 3$\sigma$意义; 质子寿命的下限，$8.34\times 10^{33}$年（90% CL），可以通过搜索设置$p\to \bar{\nu }{ķ}^{+}$; 太阳中微子的探测将为太阳金属丰度问题提供新的线索，并检查真空物质过渡区。距离 10 kpc 的典型核心坍缩超新星将导致$～5000$ 反β衰变事件和 $～2000$(300) JUNO 中的全味中微子-质子（电子）弹性散射事件。地中微子可以被探测到的速率为$～400$每年的事件。探测器的构造非常具有挑战性。在这篇综述中，我们根据 2015 年的概念设计报告（Djurcic et al., 2015）总结了 JUNO 探测器的最终设计和关键研发成果。所有 20 英寸 PMT 均已采购和测试。15,000 个 MCP PMT 的平均光子探测效率为 28.9%，5000 个打拿极 PMT 的平均光子探测效率为 28.1%，高于 JUNO 要求的 27%。与$>20$ m 在 20 吨中试净化试验中获得的液体闪烁体的衰减长度和 $>96\text{\%}$ 丙烯酸面板的透明度，我们预计每 MeV 的产量为 1345 个光电子，有效的相对能量分辨率为 $3.02\text{\%}/\sqrt{乙\mathrm{(MeV)}}$在模拟中（Abusleme 等人，2021 年）。为了保持高性能，水下电子设备被设计为具有损耗率$<0.5\text{\%}$在六年内。使用脱气膜和微气泡系统，35 kton 水池中的氡浓度可以降低到$<10$ mBq/m${}^3$. 辐射纯度亚克力板$<0.5$ 直径为 35.4 米的液体闪烁体容器的 ppt U/Th 由专用生产线生产。20 kton 液体闪烁体将通过氧化铝过滤、蒸馏、水提取和气提进行现场净化。与其他低背景处理一起，可以控制基准体积中的单曲$～10\mathrm{赫兹}$. JUNO 实验还具有一个带有 25,600 个 3 英寸 PMT 的双量热计系统、一个液体闪烁体测试设施 OSIRIS 和一个近探测器 TAO。