Attosecond X-ray pulses are a pioneering tools for real-time observation of ultrafast electronic dynamics in atoms and molecules, opening up revolutionary advances in chemistry, materials science, and condensed-matter physics. Existing attosecond sources are, however, constrained by low photon energy and flux, which limits their experimental applications. we present here start-to-end simulations of soft-X-ray FEL, taking advantage of attosecond electron beam generated from PWFA to provide terawatt-level peak power in pulses of merely tens of attoseconds duration. High-brightness electrons produced in PWFA are longitudinally compressed in a magnetic arc and then injected into an undulator. By tuning the undulator taper, two isolated spikes of radiation—each tens of attosecond duration and terawatt peak power are generated for inherent pump–probe application with tunable delays. Such an ultraintense, ultrashort source offers a direct route to table-top X-ray light sources and facilitates attosecond-resolution experiments with unprecedented intensity and time resolution.

During the coherent electron cooling (CeC) experiment at RHIC, we have encountered various challenges to align the electron beam both in the low energy beam transfer line (LEBT) and in the cooling section. For example, the electrons exit the SRF gun with an orbital angle of tens of milli-radian, which is likely caused by the misalignment of the cavity inside the cryostat as well as the tilted cathode. The significant orbital angle leads to transversely asymmetric beam in the LEBT section with deteriorated emittance. In run 23 and run 24, we have demonstrated that such orbital angle at the exit of the gun can be minimized by adjusting the position of the laser spot at the cathode. Another challenge is to align the orbit of the cooling electron beam with the circulating ion beam in the cooling section. Over the past few years, we have developed a procedure to ensure the transverse alignment to the precision of 0.1mm. The proper alignment of the two beams has been confirmed by significant growth of the ion beam’s longitudinal emittance due to its interaction with the electron beam as well as increased signal from the recombination monitor. In this paper, we will present the techniques developed for beam alignment with experimental results obtained in the CeC experiment.

Cooling of hadrons in Electron Ion Collider (EIC) at the injection energy is critical to achieving EIC design parameters. A 13 MeV electron cooler fit for the task is presently under design. This cooler will use RF-accelerated electron bunches and will provide strong cooling of the hadrons having energy of 24 GeV/nucleon. The paper describes optimization of the cooling performance, taking into account space charge, IBS and other effects, and provides physics requirements for the cooler.

GdfidL has been used to calculate the resistive wall heating in the vacuum components of the Electron-Ion Collider (EIC). In this paper, we present the simulation results for the beam-induced resistive wake potentials in various vacuum components of the EIC, including the beam screen and the hadron polarimeter in the hadron storage ring (HSR). The resistive wall losses are calculated from the wake potential computed in the finite-difference 3D electromagnetic code GdfidL and compared to the results obtained from the time-domain solver of another 3D electromagnetic code CST.

The Electron-Ion Collider (EIC) is a next-generation accelerator complex designed to enable high-luminosity collisions between highly polarized electrons and light ions (e.g., He-3). A central component of its Electron Injection System (EIS) is the Rapid Cycling Synchrotron (RCS), which accelerates a single 28 nC electron bunch from 750 MeV to 5, 10, or 18 GeV using an array of 591 MHz five-cell superconducting RF (SRF) cavities—eight at the current design stage. To ensure stable acceleration of high-charge bunches, we conducted detailed impedance and wakefield studies of the SRF cavity structure using both frequency- and time-domain methods. Wakefield solvers (ECHO3D, ECHO1D, CST), eigenmode analysis, and multi-particle tracking with ELEGANT were employed to evaluate longitudinal and transverse impedance effects and to determine instability thresholds. These studies provide critical input for the cavity design and operating parameters required to preserve beam quality and stability in the RCS.

Attosecond X-ray pulses are a pioneering tools for real-time observation of ultrafast electronic dynamics in atoms and molecules, opening up revolutionary advances in chemistry, materials science, and condensed-matter physics. Existing attosecond sources are, however, constrained by low photon energy and flux, which limits their experimental applications. we present here start-to-end simulations of soft-X-ray FEL, taking advantage of attosecond electron beam generated from PWFA to provide terawatt-level peak power in pulses of merely tens of attoseconds duration. High-brightness electrons produced in PWFA are longitudinally compressed in a magnetic arc and then injected into an undulator. By tuning the undulator taper, two isolated spikes of radiation—each tens of attosecond duration and terawatt peak power are generated for inherent pump–probe application with tunable delays. Such an ultraintense, ultrashort source offers a direct route to table-top X-ray light sources and facilitates attosecond-resolution experiments with unprecedented intensity and time resolution.