Gwo-Huei Luo

Overview of Top‐up Injection at Taiwan Light Source

During the last two years, a series of beam parameters measurement, subsystem checkout, installation of various sensors, control program modification and hardware upgrade made the top‐up injection possible in practical routine operation. Top‐up injection is an operation mode in which the beam current in the storage ring is maintained above certain level by frequent injections. The routine current stability is in the range of 10−3 for long period of operation. The Top‐up injection provides advantages in operation such as lower emittance, higher current, smaller coupling, smaller ID gaps, exotic bunch filling patterns, and higher bunch charge. It also provides constant thermal loading on all components in the storage ring and the optics components of beamlines, as well as constant signal to the beam position monitor. Discussions on the results of some measurements of booster and storage ring, the requirement of hardware upgrade and the summary of routine Top‐up operation will be presented in this paper.

Operational experience of the insertion devices and expectation of the future superconducting wigglers at NSRRC

Since 1995, we have continuously installed five insertion devices (IDs) in the 1.5 GeV storage ring TLS at NSRRC. They include three undulators (U5, U9 and EPU5.6), one 1.8 Tesla wiggler (W20) and one 6 Tesla superconducting wavelength shifter (SWLS). All these five IDs are located in the long straight sections. The real time orbit correction and betatron tune compensation routine have been successfully operated. With these IDs, the machine emittance reduces substantially. We plan to install four more superconducting multi-pole wigglers (SMPWs), one in the long straight and three in the archromat sections. These devices therefore can offer more beam time for the hard X-ray community. The impacts of these IDs on the beam dynamics effects are reported in this paper.

Revision of Booster to Storage Ring Transport Line Design and Injection Scheme for Top-Up Operation at NSRRC

In order to help the operation of constant current, the optics of booster to storage ring transport line (BTS) design is reinvestigated[1]. The initial Twiss parameters are derived by measurement. The optics of the transport line is readjusted according to the measured initial beam parameters. The design of pulse width of the injection kicker is also changed from 1.2 μs to 2.0 μs. The injection scheme is reviewed and the effects of the kicker error on both injected and stored beam are investigated and shown in this report.

The 1.5 GeV operation parameters and performance at SRRC

The storage ring at SRRC is highly promising as an ultraviolet to soft X-ray radiation source for use in basic research and industrial applications. Energy ramping of the storage ring can push the critical photon energy to the edge of hard X-ray. The tune drifting, during the ramping procedure, is expected and should be minimized such that the beam can survive through the ramping process. The betatron frequencies and the ramping function of magnets were carefully monitored in order to avoid the betatron tunes crossing the fatal resonance line. A successful ramping results and lattice parameters were measured and discussed in this paper. The measured photon flux increased by six to seven folds at the X-ray beam line. Life time reaches 9 hours of 200 mA beam current.

First Year Performance of the TPS Booster Ring

Abstract The Taiwan Photon Source (TPS) is a 3-GeV lowemittance light source of circumference 518.4 m. The booster ring is in the same tunnel with the storage ring; its circumference at 496.8 m makes it the largest booster ring in operation in existing light sources. Since the successful commissioning at the end of 2014, the TPS booster ring has been optimized in performance for routine operation. In this paper, we present the system upgrade and the improvement of the ramping procedure to increase the capture and ramping efficiency of the beam charge, the characterization of the optics, etc.

Improvements to the injection efficiency at the Taiwan Light Source

The Taiwan light source began top-up operation in October 2005 with an initial beam current of 200 mA. This was subsequently raised to 300 mA. In the early phase of top-up operation, the injection efficiency varied markably under different machine operating conditions. A procedure to optimize and maintain the injection efficiency is presented. Future improvements and the prospects for a 400 mA top-up operation are discussed.