Recent days saw the launch event of the second phase of the China Spallation Neutron Source (CSNS), a national major science and technology infrastructure in Dongguan. With the commencement of the second phase, the CSNS is officially "expanding," significantly boosting its research capabilities, broadening its research scope, and enhancing experimental precision and efficiency.

Eleven neutronspectrometers and experimental terminals to be constructed in the second phase

The CSNS, hailed as a "super microscope" for exploring the microstructure of materials, utilizes neutrons as probes to discern materials' microscopic structures. Since its opening over five years ago, the first phase has seen a rapid increase in users, with over 6,000 registered users and a demand surpassing the available machine time. Currently, over 1,500 experiments have been conducted (including over 100 from Hong Kong, Macao, Taiwan, and abroad). Based on this success, the second phase received rapid approval and commenced construction. The preliminary design estimate for the second phase was approved by the National Development and Reform Commission on January 9th, 2024, with a construction period of 5 years and 9 months.

According to Wang Sheng, Deputy Director of the Institute of High Energy Physics, Chinese Academy of Sciences, and General Commander of the CSNS PhaseIIproject, 11 neutron spectrometers and experimental terminals (including 9 neutron spectrometers, 1 high-energy proton beam experimental terminal, and 1 muon source experimental terminal) will be primarily constructed in the second phase. After completion, the number of neutron spectrometers will increase to 20, with the addition of the country's first muon experimental terminal and high-energy proton experimental terminal. Additionally, the power of the accelerator's target beam will increase from the first phase's 100 kilowatts to 500 kilowatts.

Muons are unique particles in the standard model of particle physics and have wide-ranging applications. A high-performance muon source is an important experimental platform for comprehensive scientific research internationally. Wang Sheng explained that muons and neutrons are ideal probes for detecting themicrocosm,each with its own characteristics that complement each other. Once the muon source is completed, it will play an important role in fields such as magnetic materials, new energy materials, and superconducting materials.

Providing crucial support for breakthroughs in national key core technologies

The production of neutrons involves using a high-intensity proton beam to generate neutrons through bombardment. Therefore, the power of the proton beam is one of the important indicators to measure the performance of the facility. In the second phase, the power of the accelerator's target beam will increase to 500 kilowatts, indicating a significant increase in neutron flux. This will enable experimenters to conduct more experiments in the same amount of time and measure even smaller amounts of experimental samples.

If the spallation neutron source is likened to a "super microscope," then the neutron spectrometer is the "lens" of each "microscope." Specifically, the spectrometer uses neutrons as a medium to conduct various experiments or applications, comprising a set of complex experimental devices. The second phase aims to construct 11 neutron spectrometers and experimental terminals.

Once the new facilities are operational, they will provide indispensable support for breakthroughs in national key core technologies in numerous fields, including research into superconducting and magnetic quantum materials, life sciences, catalysis, rare earth functional material design and development, lithium-ion and hydrogen storage battery research and development, deep-sea methane hydrate and shale oil exploration and storage, as well as cancer and antiviral drug research.

Source: Yangcheng Evening News

“超级显微镜”扩容后能干什么？

近日，国家重大科技基础设施中国散裂中子源二期工程启动会在东莞举行。二期工程的开建，意味着中国散裂中子源正式“扩容”，装置研究能力将大幅提升，研究领域将进一步拓展，实验精度和效率将显著提高。

二期工程将建设11台中子谱仪和实验终端

中国散裂中子源被誉为探索物质材料微观结构的“超级显微镜”，是以中子为“探针”，“看穿”材料的微观结构。一期工程建成开放5年多来，用户迅速增加，目前注册用户已超过6000人，机时供不应求。截至目前，已完成1500余项（含港澳台地区及国外100余项）用户实验课题。基于此，二期工程得以快速立项并启动建设。二期工程初步设计概算于2024年1月9日获国家发展改革委批复，建设周期为5年9个月。

据中国科学院高能物理研究所副所长、中国散裂中子源二期工程总指挥王生介绍，二期工程主要建设11台中子谱仪和实验终端（包括9台中子谱仪、1个高能质子束实验终端和1个缪子源实验终端），建成后中子谱仪数量将增加到20台，并新增国内首台缪子实验终端和高能质子实验终端；同时，加速器打靶束流功率将从一期的100千瓦设计指标提高到500千瓦。

缪子是粒子物理标准模型中基本粒子中的一种，性质独特且应用广泛。高性能的缪子源是国际上综合性科学研究的重要实验平台。王生介绍，缪子和中子都是探测微观世界的理想探针，两者各具特色，可以互补。缪子源建成后，将在磁性材料、新能源材料、超导材料等领域发挥重要作用。

将为国家关键核心技术突破提供重要支撑

中子的产生是用强流质子束打靶产生中子，因此质子束束流功率成为衡量装置性能的重要指标之一。二期工程中，加速器打靶束流功率将提高到500千瓦，这意味着中子通量大幅度提升，实验人员能在相同时间内完成更多实验，也能测量更微量的实验样品。

如果把散裂中子源比作“超级显微镜”，那么中子谱仪就是一个个“显微镜”的“眼睛”，具体而言，谱仪就是利用中子作为媒介，开展各种实验或应用的一套复杂实验装置。二期工程要建设11台中子谱仪和实验终端。

新装置上线后，将在超导和磁性量子材料机理研究、生命科学研究、催化等化学化工材料机理研究、稀土功能材料设计研发、锂离子和储氢电池研发、深海可燃冰和页岩油的开采存储、抗癌症和病毒药物研发等众多领域为国家关键核心技术突破提供不可或缺的支撑。

文丨记者 余晓玲
图丨记者 王俊伟
翻译丨刘佳慧