Laser plasma accelerators (LPA) are expected to achieve acceleration gradients several orders of magnitude higher than conventional accelerators, thereby providing a promising route to the development of compact high-energy particle accelerators. However, the electron beams generated by current LPAs exhibit considerable energy spread and significant shot-to-shot energy jitter—issues that are particularly pronounced for high-charge bunches—severely restricting their practical application in fields such as ring injectors. Our team proposed a transfer line configuration integrating an active plasma dechirper, a passive plasma dechirper, and magnetic chicanes (Xueyan Shi et al. New J. Phys. 26, 073045, 2024). Start-to-end simulations demonstrated that for 500 MeV electron beams with a charge of 500 pC, this scheme reduces the energy jitter from ±2% to 0.1% and the energy spread from 1.2% to 0.5%. In the present work, we extend the beam charge to the nanocoulomb (nC) level to explore the performance limits of this approach. Preliminary simulation results show that for a 1 nC electron beam with an initial root-mean-square (rms) energy spread of 1.2% and energy jitter of ±2%, the proposed scheme can reduce these parameters to 0.2% and 0.4%, respectively, while maintaining a transmission efficiency of 81.2%. Additionally, we verified the feasibility of using such LPA-generated beams as injectors for the High Energy Photon Source (HEPS) booster by simulations.

To meet the beam commissioning requirements of the High Energy Photon Source (HEPS), a new pure-Python framework named Pyapas was developed, serving as the foundation for all high-level applications (HLAs) at HEPS. Beam commissioning of the Linac began on March 9, 2023, where the HLAs performed exceptionally well, enabling the Linac to achieve its design specifications and pass acceptance. By mid-2023, the development of all booster HLAs was completed, paving the way for beam commissioning in late July, which proceeded smoothly and concluded with successful acceptance in November 2023.In 2024, the team shifted its full focus to developing HLAs for the storage ring. The development phase was completed in June, followed by several rounds of offline testing with the virtual accelerator and integrated system tests. These efforts ensured the readiness of the HLAs, which supported the successful commissioning of the storage ring and the emission of its first light in October 2024. By the end of 2025, HEPS has met all performance targets and successfully passed process acceptance. This paper provides a concise review of recent progress in HLA development at HEPS, highlights key achievements during booster and storage-ring commissioning, and outlines the roadmap for future work

The Plasma Wakefield Acceleration (PWFA) experimental platform consists of two beamlines. Beamline 1 (BL1) transports the electron-positron beams from the BEPCII linear accelerator to the experimental station, with a beam energy of 2 GeV. Beamline 2 (BL2) is a linear accelerator featuring an energy of 150 MeV and a bunch charge exceeding 5 nC. Currently, both beamline accelerators have entered the beam commissioning phase. Pyapas, an independently developed High-Level Application (HLA) by the Institute of High Energy Physics (IHEP), has been successfully applied to beam commissioning of high-energy light sources. We have achieved the successful porting and application of Pyapas in the beam commissioning of the PWFA linear accelerators.

The High Energy Photon Source (HEPS) is a 35-pm, 1360-m storage ring light source being built in the suburb of Beijing, China. The HEPS construction started in 2019, with the main civil construction finished at the end of 2021. In the past two years, the beam commissioning of the HEPS storage ring had been started and bascially finished. In this paper, we will briefly introduce commissioning of the HEPS storage ring, and relavent physics studies.

The High Energy Photon Source is the first fourth-generation synchrotron light source in Asia. As a green-field facility, HEPS began construction in 2019 and now the commissioning of the storage ring has been basically finished. The booster synchrotron, serving as the second-stage accelerator, completed its initial beam commission-ing between July and November 2023 and was officially put into operation in July 2024 to support the storage ring commissioning. This paper presents the beam per-formance of the booster since the start of operation, key upgrades and optimizations implemented, major opera-tional challenges encountered, and the ongoing plans for further performance enhancement

Measurement of the response matrix serves as the foundation for orbit correction and OPICTS correction. To obtain more accurate response matrix data while minimizing the measurement time, we have meticulously optimized parameters such as the number of data points collected by Beam Position Monitors (BPMs) and the waiting time. Additionally, due to the long overall measurement duration for the entire ring, factors including orbit drift and hysteresis effects during the process can introduce deviations to the measurement results. Therefore, we integrated response matrix measurement with orbit correction and radio frequency (RF) frequency adjustment to further ensure the consistency of the beam state throughout the entire measurement process. This paper will elaborate on the relevant work in detail

The High Energy Photon Source (HEPS) is the first fourth-generation synchrotron light source in Asia. In HEPS storage ring, there are five 166.6 MHz superconducting cavities serving as fundamental cavities and two 499.8 MHz superconducting cavities as active third harmonic cavities. The employment of active harmonic cavities enables ‘ideal bunch lengthening’ at any beam current, laying a foundation for flexible beam operation. Beam commissioning of the HEPS storage ring started on July 23, 2024. Due to the presence of delays in the 166.6 MHz cavities, the 499.8 MHz cavities were temporarily utilized as fundamental cavities to provide the required beam acceleration for the first-year commissioning. Starting from August 2025, we initiated the commissioning of an active double-RF system composed of the 166.6 MHz and 499.8 MHz cavities, successfully realizing ideal bunch lengthening under different beam current. Since August 2025, we have commissioned the active double-RF system, successfully achieving ideal bunch lengthening under various beam current conditions. During the ring commissioning process, some beam phenomena associated with the operation of the double-RF system were observed, and experiences in commissioning active double-RF systems was accumulated. This paper reports the key experiences gained from the commissioning and operation of the active double-RF system in the HEPS storage ring, aiming to provide references for similar accelerator projects.

The High Energy Photon Source (HEPS) adopts on-axis swap-out injection to relax the dynamic-aperture requirement of its ultralow-emittance storage ring. To provide high-charge bunches for swap-out operation, a booster-based beam-recycling scheme has been developed, in which a depleted storage-ring bunch is extracted, transported to the booster, combined with a newly accelerated bunch at high energy, damped, and reinjected into the original storagering bucket. This paper summarizes the commissioning status of this scheme. Closed-loop beam recycling has been demonstrated, paving the way for user operation toward high bunch charge. The results validate the basic beam-recycling architecture and identify the main directions for further optimization toward routine high-charge operation.

Beam-driven plasma wakefield acceleration (PWFA) holds considerable promise for next-generation electron-positron colliders and high-energy free-electron lasers, owing to its ultrahigh accelerating gradients. In particular, sustained experimental breakthroughs worldwide indicate that the field is now entering a critical phase toward key advances. To address fundamental physics and technical challenges associated with both electron and positron acceleration in PWFA, the Institute of High Energy Physics (IHEP) has established a plasma wakefield acceleration experimental platform based on the Beijing Electron-Positron Collider (BEPCII). The platform comprises two beamlines and a petawatt laser system. Beamline I deliver electron and positron beams from BEPCII to the experimental area, while Beamline II is a newly constructed 150 MeV high-performance linear accelerator. Together, these beamlines support a range of plasma acceleration experiments, including positron acceleration, electron-cascade acceleration, high transformer-ratio electron acceleration, and external-injection electron acceleration. Notably, Beamline II is capable of generating electron beams with a bunch charge exceeding 5 nC and a peak current above 10 kA. This paper presents a detailed overview of the physics design and current progress of Beamline II.

The upgrade of Beijing Electron and Positron Collider-II has begun since the shutdown of BEPCII on July 1st in 2024. The hardware replacement and upgrade is expected to finish by the end of the year 2024, and the machine commissioning of BEPCII upgrade project will start at the beginning of the year 2025. In this paper, we will show the commissioning results of the BEPCII uprade project.

Laser plasma accelerators (LPA) are expected to achieve acceleration gradients several orders of magnitude higher than conventional accelerators, thereby providing a promising route to the development of compact high-energy particle accelerators. However, the electron beams generated by current LPAs exhibit considerable energy spread and significant shot-to-shot energy jitter—issues that are particularly pronounced for high-charge bunches—severely restricting their practical applications in fields such as ring injectors. Our team proposed a transfer line configuration integrating an active plasma dechirper, a passive plasma dechirper, and magnetic chicanes (Xueyan Shi et al. New J. Phys. 26, 073045, 2024). Start-to-end simulations demonstrated that for 500 MeV electron beams with a charge of 500 pC, this scheme reduces the energy jitter from ±2% to ±0.1% and the energy spread from 1.2% to 0.5%. In the present work, we extend the beam charge to the nanocoulomb (nC) level to explore the performance limits of this approach. Preliminary simulation results show that for a 1 nC electron beam with an initial root-mean-square (rms) energy spread of 1.2% and energy jitter of ±2%, the proposed scheme can reduce these parameters to 0.4% and ±0.05%, respectively, while maintaining a transmission efficiency of ~82%. Furthermore, simulation results validate the feasibility of adopting LPA beams for HEPS booster injection.

Plasma acceleration is an innovative principle characterized by high acceleration gradients, which has attracted significant interest from major accelerator laboratories worldwide, because of its potential to increase accelerator energy and reduce size. One promising approach involves using existing conventional accelerators as external injectors for plasma-based accelerators, a topic of considerable interest within the research community. At IHEP, we propose utilizing the BEPCII Linac in conjunction with a new linac based on a photocathode RF gun to develop a new plasma acceleration research platform. The platform consists of two beamlines and a PW laser system. This manuscript presents recent progress of the two beamlines of this platform.