China lights up ‘super microscope’ hopes with world-leading electron gun beam

China has successfully produced an advanced electron beam using a cutting-edge electron gun, bringing the nation closer to constructing a "super microscope." The Hefei Advanced Light Facility (HALF), located in central China's Anhui province, achieved this milestone on September 20 by firing its first electron beam. High-speed electrons were accelerated to a record-breaking 2.2 billion electron volts by a 192-meter linear accelerator, marking a significant advancement for the fourth-generation light source project.

He Zhigang, a scientist involved in the project, explained that attaining a successful beam signifies a crucial step towards their ultimate objective. He also noted that the beam's quality, stability, and reliability have a profound impact on the experiments conducted at HALF. The University of Science and Technology of China reported that HALF's designed brightness and stability are the highest globally.

The project's chief, Feng Donglai, an academician of the Chinese Academy of Sciences, confirmed that all the critical components for the linear accelerator were developed domestically. Like other light source projects, HALF aims to harness exceptionally bright X-rays, generated when high-speed electrons interact with magnetic fields, to observe matter at the atomic level.

Compared to previous generations, fourth-generation light sources, such as HALF, control electron beams with greater precision, resulting in finer and more concentrated beams that produce brighter X-rays. These X-rays will be up to 100 times brighter and more coherent than those emitted by third-generation sources, enabling novel experimental techniques.

The facility will contain up to 35 experimental stations accessible to scientists worldwide, facilitating breakthroughs in fields such as high-temperature superconductivity, new energy batteries, advanced materials, and life sciences, including Alzheimer's research. The first ten stations will include a platform for extreme ultraviolet lithography, a crucial technology for manufacturing advanced semiconductors currently subject to US-led export controls.

Additional stations will focus on nano-devices. Construction of HALF began in 2023, with the project slated for completion in 2028. HALF, along with the High Energy Photon Source in Beijing and the Shanghai Synchrotron Radiation Facility, will comprise China's advanced light source system, encompassing high-, medium-, and low-energy ranges.

The type of electron beam utilized by HALF was initially considered a by-product of high-energy physics experiments. Early light sources relied on the Beijing Electron-Positron Collider, which commenced operation in the late 1980s. In 1989, China successfully built its first dedicated "super microscope," the Hefei Light Source. Since then, third-generation light sources have yielded significant discoveries, such as unraveling the molecular mechanism of arsenic in treating leukemia, uncovering the three-dimensional structure of the Sars virus, and imaging an ancient dinosaur fossil trapped inside 99 million-year-old amber.