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A proposal has been made for the construction of a new generation of high-luminosity electron-positron colliders known as the Super Tau-Charm Facility (STCF) in China. The STCF aims to achieve a luminosity exceeding $0.5\times 10^{35}$cm${}^{-2}$s${}^{-1}$ and will operate within a center-of-mass energy range of 2 to 7GeV. Given the design challenges of the STCF collider ring, swap-out injection has been proposed as an alternative method for achieving the desired luminosity. Consequently, the STCF injector will explore both off-axis injection and swap-out injection methods concurrently. This paper will detail the ongoing research progress on these two injection techniques.

The Circular Electron–Positron Collider (CEPC) is a 100-km ring $e^{+}{e}^{-}$ collider for a Higgs factory. The injector of CEPC is composed of Linac and Booster. The Linac is a normal conducting S-band Linac with a frequency of 2860 MHz; it provides electron and positron beams at an energy of up to 10 GeV with 100 Hz repetition frequency of 100 Hz. The Linac design and dynamic simulation results are discussed in detail in this paper, including electron bunching system, positron source, electron bypass transport line, damping ring and main Linacs.

The CUP experiment is a first important step of a more ambitious project that investigates the possibility to create new powerful sources of high-frequency monochromatic electromagnetic radiation: crystal undulator and γ-laser based on channeling of positrons in crystals. Moreover, within the CUP project we are going to design a new experimental facility based on positron source. In this work the main goal of the CUP experiment and the first measurements at the DAΦNE BTF facility will be presented.

With the LHC a new era of measurements at the energy frontier has started, and exciting new discoveries are expected. However, also measurements at the precision frontier will be necessary to fully understand the underlying physics model. The programme for the e⁺e⁻ collider projects ILC and CLIC is focused on precision tests of the Standard Model and new physics beyond it at the TeV scale. Polarized positron beams play a crucial role in these analyses. Here, the advantages as well as the requirements using also polarized positron beams for measurements at e⁺e⁻ colliders are discussed.

To achieve the extremely high luminosity for colliding electron-positron beams at the future International Linear Collider¹ (ILC) an undulator-based source with about 230 meters helical undulator and a thin titanium-alloy target rim rotated with tangential velocity of about 100 meters per second are foreseen. The very high density of heat deposited in the target has to be analyzed carefully. The energy deposited by the photon beam in the target has been calculated in FLUKA. The resulting stress in the target material after one bunch train has been simulated in ANSYS.

The ILC positron system uses novel helical undulators to create a powerful photon beam from the main electron beam. This beam is passed through a titanium target to convert it into electron-positron pairs. The target is constructed as a 1 m diameter wheel spinning at 2000 RPM to smear the 1 ms ILC pulse train over 10 cm. A pulsed flux concentrating magnet is used to increase the positron capture efficiency. It is cooled to liquid nitrogen temperatures to maximize the flatness of the magnetic field over the 1 ms ILC pulse train. We report on prototypiog effort on this system.