It has been shown that a transverse deflecting cavity (TDC)-based de-chirper can be made by altering the drift sections in a TDC-based chirper to form negative drifts. While five appropriately configured quadrupole magnets can implement such negative drifts, this approach is limited by spatial and experimental constraints. In this study, we investigate an alternative configuration that uses three quadrupole magnets to form a negative identity transport section between the TDCs instead of a negative drift. To assess the robustness of this proposed design, a computational study has been conducted on initial beam conditions to determine the operational limitations. This includes the effects of space charge and initial transverse beam conditions, such as beam size and divergence, on the resulting transverse emittance.

It has been shown that a transverse deflecting cavity (TDC)-based de-chirper can be made by altering the drift sections in a TDC-based chirper to form negative drifts. While five appropriately configured quadrupole magnets can implement such negative drifts, this approach is limited by spatial and experimental constraints. In this study, we investigate an alternative configuration that uses three quadrupole magnets to form a negative identity transport section between the TDCs instead of a negative drift. To assess the robustness of this proposed design, a computational study has been conducted on initial beam conditions to determine the operational limitations. This includes the effects of space charge and initial transverse beam conditions, such as beam size and divergence, on the resulting transverse emittance.

We present a compact electron buncher that uses a permanent magnet setup for beam focusing. The buncher modulates the input direct-current beam into 5.7-GHz bunch train. The buncher consists of two radiofrequency (RF) cavities. Immediately downstream of each RF cavity, there is an electrostatic potential depression (EPD) section. An EPD section in an electrically insulated beam pipe biased with a negative high voltage. The EPD method remarkably shortens the buncher structure by rapidly forming the bunch train. Each of the RF cavities and the EPD sections uses an individual set of rectangular permanent magnets, arranged in a circular array, which provide a solenoid-like focusing field. The polarity of the magnets is configured to form an alternating on-axis magnetic field orientation for minimizing the total weight. Coarse adjustment of the magnetic field is achieved by adding or removing permanent magnet rectangles. For fine adjustments, the rectangles are moved evenly in the radial direction. We show simulation results of the buncher performance and the tunable magnetic focusing. Initial experimental results are also reported.

The Transverse Deflecting Cavity Based Chirper (TCBC) is a novel concept of imposing and removing a significant energy chirp of an ultra-relativistic electron beam. The TCBC method requires much less footprint, compared to the conventional chirping and dechirping method involving operating a linear accelerator off-crest. When the compressed bunch is very short, the dechirping has to rely on the wakefields. We present our updated design of the L-band traverse deflecting cavity (TDC) for demonstrating the TCBC concept at the Argonne Wakefield Accelerator (AWA) facility. Our TDC design update is based on the original design provided by Tsinghua University. The TDC design update focused on ensuring improved performance under more intense electromagnetic fields, reducing the peak pulsed temperature rise. The tuners of the TDC were meanwhile reworked to allow greater adjustability of the resonant frequency and of the electromagnetic field balance among the cells. We also report the tolerance study of the TDC. Two copies of the TDC with the updated design are currently under fabrication with Dymenso, LLC.