Taiwan Photon Source Storage Ring Research Articles

Optimization stability and performance of the TPS storage ring dipole magnet power supply

This article focuses on the current status of the dipole magnet power supply (DMPS) and improvement in the Taiwan Photon Source (TPS) storage ring. The DMPS provides a stable and precise magnetic field for the storage ring operation. Appropriate wiring methods are employed to minimize magnetic field interference across the entire TPS area to meet the demands of high-energy output and overcome the challenges of operating at high currents. The target energy is set at 850 V and 750 A, utilizing a single-pole switching voltage regulator as a high-precision constant current source output structure. The system incorporates a closed control loop that uses the Direct Current Current Transducer (DCCT) to provide current signal feedback to the system. FPGA (Field-Programmable Gate Array) calculates PID (Proportional-Integral-Derivative) compensation values, generating a 2.1 kHz pulse width modulation (PWM) signal to regulate the output current. At the same time, insulated gate bipolar transistor (IGBT) modules are switching components. However, even after several years of practical operation, the stability and performance of the DMPS in the storage ring still require improvements. To enhance long-term output current stability and address peripheral issues, the current TPS utilizes the Beam Orbit Feedback (FOFB) system to suppress and fine-tune the magnetic field and compensate for the impact of temperature drift on the DMPS's output current. This improvement ensures a more stable circulation of the photon beam within the storage ring. By optimizing the temperature control circuit of the main control card, the long-term output current stability has been successfully enhanced to within ± 10 ppm. Simultaneously, the FOFB system reduces uncertainties in adjusting the X-axis beam position, improving beam stability and quality. Furthermore, relevant protective measures have been implemented to ensure robust system operation. Ultimately, these improvement measures have successfully met TPS's stringent requirements for the DMPS, enabling the synchrotron accelerator light source to operate at higher performance levels and fostering advanced scientific research. The results of these upgrades underscore the success of the power supply enhancements, making significant contributions to the overall improvement of the Taiwan Photon Source facility.

Optimization and Measurements on the Double Mini-Betay Lattice in the TPS Storage Ring

The Taiwan Photon Source (TPS) is capable of operating in multi-bunch and single-bunch mode. To operate in a hybrid mode as requested by users, we developed a lattice with chromaticities of 0.8/2 (ξx/ξy) to provide higher single bunch currents. Beam dynamics simulations and lattice characterizations including dynamic aperture, frequency map analysis, tune shift with energy, tune shift with amplitude, and betatron coupling will be discussed in this report.

Optimization and Measurements on the Double Mini-Betay Lattice in the TPS Storage Ring

The Taiwan Photon Source (TPS) is capable of operat-ing in multi-bunch and single-bunch mode. To operate in a hybrid mode as requested by users, we developed a lattice with chromaticities of 0.8/2 (x/y) to provide higher single bunch currents. Beam dynamics simulations and lattice characterizations including dynamic aperture, frequency map analysis, tune shift with energy, tune shift with amplitude, and betatron coupling will be discussed in this report.

Improvement the Bending Magnet Power Supply Performance for TPS Storage RING

In the TPS (Taiwan Photon Source) facility, current stability of the electron beam depends on the bending magnet power supply and an orbit FOFB system to compensate the magnetic field. Due to the output current stability of the bending magnet power supply drifts with temperature so the orbit FOFB system should be applied to fine tune magnetic field and the photon beam should circulate in storage ring. In this paper, to stabilize the temperature of regulation circuit’s temperature box of the bending magnet power supply, the long-term output current stability is improve from ± 50ppm to ± 10ppm, and orbit FOFB system substantially reduce the tune X of beam position, effectively increasing the beam current stability and quality. In the TPS (Taiwan Photon Source) facility, current stability of the electron beam depends on the bending magnet power supply and an orbit FOFB system to compensate the magnetic field. Due to the output current stability of the bending magnet power supply drifts with temperature so the orbit FOFB system should be applied to fine tune magnetic field and the photon beam should circulate in storage ring. In this paper, to stabilize the temperature of regulation circuit’s temperature box of the bending magnet power supply, the long-term output current stability is improve from ± 50ppm to ± 10ppm, and orbit FOFB system substantially reduce the tune X of beam position, effectively increasing the beam current stability and quality.

Design and Performance Measurement of Control System for Elliptically Polarized Undulators in Taiwan Photon Source

In phase I of the Taiwan Photon Source (TPS) project, three elliptically polarized undulators (two EPU48 and one EPU46) are installed in the TPS storage ring. The control system for these EPU48 and EPU46 is based on the EPICS architecture; all control functionality is coordinated by the CompactPCI EPICS IOC. The main control components include motors with an encoder for gap adjustment and phase moving, a trimming power supply for corrector magnets, temperature sensors for environmental monitoring of the insertion devices, and an interlock system (limit switches, tilt sensor, emergency button) for safety. The closed-loop control is essential for the gap and phase motion to avoid the effects of magnetic forces. All motors of the gaps must be synchronized to move without tilt. An interface for ID beamline users is included to assist with experiments, such as to control the ID gap or phase and experiments on the fly. The features and benefits of the EPU48 and EPU46 control systems are summarized in this paper.

Taiwan’s science miracle

In the past two decades, a flourishing economy and maturing infrastructure have Taiwanese physicists both staying home more and engaging internationally.

High heat load absorbers in Taiwan Photon Source storage ring

Taiwan Photon Source (TPS) is under construction at the National Synchrotron Radiation Research Center (NSRRC). This 518 m circumference synchrotron accelerator will generate 3 GeV and 500 mA high-energy X-rays. Absorbers in the storage ring will receive relatively high power densities (at a distance of 2.2 m from the dipole source). Three types of crotch absorbers for B1–B3 storage chambers were designed and prototyped. An end absorber in B3 is also designed and implemented to protect the downstream components in the chamber from being heated by the synchrotron radiation. Intensive vacuum brazing between Oxygen Free High Conductivity copper (OFHC) and stainless steel was carried out while fabricating the absorber assembly. The analysis, design and construction of several absorbers are reported in this paper.