China's "super microscope": High Energy Photon Source enters joint commissioning phase

Beijing, March 27, 2025 – The Institute of High Energy Physics (IHEP) of the Chinese Academy of Sciences announced today that the High Energy Photon Source (HEPS), a major national science and technology infrastructure project, has successfully completed its preliminary beam commissioning and officially entered the joint commissioning phase (Figure 1A). With an investment of 4.76 billion RMB (∼$657 million), this “super microscope” is designed to redefine the spatiotemporal resolution limits of matter structure research by delivering X-rays with a brilliance that surpasses that of sunlight by a trillion-fold.

As of the current technological landscape, merely three fourth-generation light source facilities in Sweden, France, and Brazil have been in operation; APS-U in the United States, HEPS in China, and SLS 2.0 in Switzerland are the other facilities under commissioning. As the world’s fifth and Asia’s first fourth-generation synchrotron radiation facility, HEPS is designed to push accelerator and beamline performance close to physical limits, serving as a “super probe” for matter structure exploration. Behind these extreme parameters lies an engineering challenge: how to control particle dynamics and high-precision X-rays under such conditions with innovative technology. With the first idea proposed in 2008 and construction commencing in June 2019, HEPS represents the culmination of a decade of feasibility studies, technical planning, and breakthroughs by Chinese researchers.

The development of the HEPS accelerator complex highlights the immense challenge of balancing key performance indicators such as source brightness, beam emittance, dynamic aperture, and beam lifetime. To achieve ultralow emittance and significantly enhanced brightness, HEPS incorporates novel approaches in accelerator physics and engineering. Its storage ring employs a hybrid multi-bend achromat (MBA) lattice—a “magnetic array” composed of dipole, quadrupole, sextupole, and octupole magnets. By increasing the number of dipoles to reduce deflection angles of individual magnets while deploying high-gradient quadrupoles for stronger focusing—along with reverse-bending dipoles and combined-function magnets—the beam emittance is designed to be the lowest.