THz-driven dielectric particle accelerator on chip.

Recently, terahertz (THz)-driven particle accelerators have drawn increasing attention. The development of high-energy-gain THz accelerators on chip has been a challenge. Here we propose a concept of an on-chip THz-driven particle accelerator that uses few-cycle THz pulses to drive dielectric prisms. It avoids the serious waveguide dispersion of previous THz linacs based on dielectric lined waveguides and enhances the electron-energy gain. In addition, we propose to use prism stacks to overcome the asynchronization effect when accelerating low-energy particles, by which a longer acceleration length with even higher energy gain can be realized. Compared with the available on-chip dielectric laser accelerators, the proposed scheme avoids serious dielectric dispersion and enhances accelerated bunch charge. Hence, it promises an attractive particle accelerator on chip.

A dual-ring network design for the fast orbit feedback system of the storage ring.

Building reliable fast orbit feedback (FOFB) systems to offer high stability of the beam orbit becomes more challenging for the diffraction-limited storage ring due to the smaller beam size. The beam position measurement and control (BPMC) processor has been developed to streamline the FOFB system architecture by integrating BPM (Beam Position Monitor) electronics and an orbit feedback controller. This paper designs a hierarchical dual-ring network topology based on BPMC processors using parameters derived from the storage ring of the Hefei Advanced Light Facility. To reduce latency and prevent data transmission collisions, we propose a multi-forwarding communication scheme and a communication controller design in a field-programmable gate array. Experimental results verify that this topology operates reliably with the multi-forwarding scheme, providing an approximate communication latency as low as 17.336 µs to support the 30 kHz orbit feedback update rate.

Data synchronization module for multi-dimensional bunch-by-bunch measurement in a storage ring.

Multi-dimensional bunch-by-bunch (BbB) measurements are an efficient tool to research beam dynamics induced by wakefields in storage ring light sources, yet they can have data misplacement problems on high-speed acquisition boards. Hence, a data synchronization module (DSM) was designed to solve the issue of data misplacement. We analyzed different synchronization states in the DSM and conducted testing of the DSM on a field programmable gate array to evaluate its performance. Test results indicate the synchronized DSM data from multiple high-speed acquisition boards corresponds to the bucket number in the bunch filling pattern. We found that the resolution of the longitudinal phase in three-dimensional BbB measurements can be improved with DSM and propose a scheme for multi-dimensional BbB measurements. In this paper, we will detail the structure of DSM and its limitations.

Micro telecom computing architecture.4-based beam position monitor electronics design for storage ring of Hefei advanced light facility.

The Hefei Advanced Light Facility (HALF) is a fourth-generation vacuum ultraviolet and x-ray diffraction limit synchrotron radiation (DLSR) light source now under preliminary research. To achieve ultralow beam emittance and small beam size, the orbit of the beam in the DLSR storage ring should meet the stability requirement at submicrometer scale. The beam position monitor (BPM) electronics measures the orbit and is hence an essential part of the beam orbit control system. In this article, we design a BPM electronics based on the MicroTCA.4 (Micro Telecom Computing Architecture) standards platform, which consists of a MicroTCA.4 module (including a chassis, a power supply, and a digital board), a customized RF front end module, and a frequency synthesizer. In-phase and quadrature sampling and digital signal processing algorithms are implemented to obtain turn-by-turn data, fast acquisition data at a 10 kHz rate, and slow acquisition data at a 10 Hz rate. To evaluate the performance and function of BPM electronics, we conducted offline tests in the laboratory and beam tests based on the storage ring of Hefei Light Source II (HLS II), a light source similar to the HALF as an alternative. Test results indicate that the performance of MicroTCA.4-based BPM electronics can meet the requirements of the HALF storage ring.