Search

TPS (Taiwan Photon Source) beamlines have operated for three years after the successful commission in 2015. Recently, the electromagnetic activated pressure relief valve of cryogenic phase separator of beamline had malfunction due to the rust of its control circuits. After on site observation and temperature records, the water was found to be condensed around the outlet area due to fast temperature dropping near the valve as it was activated. Such situation would cause the rust of metal components due to humidity after a certain period of time. To avoid such event, fan is used to blow the condensed water and silicone heat belts are added to increase the local temperature with unique designed clamp for fixing the fan, sensors and safety circuit breaker. Via the temperature control system, the temperature monitoring, setting and the abnormal situation can be access on web page through Ethernet to make sure the proper operation of the protected devices. The instrument has been operated since Dec. 2018. After four months of operation, the moist situation has been improved and the relief valve is no longer frosted., Proceedings of the 10th Int. Particle Accelerator Conf., IPAC2019, Melbourne, Australia

In order to provide short bunch length for picosecond time-resolved experiments and for coherent IR/THz radiation, low momentum compaction factor (alpha) lattices have been commissioned recently at the Taiwan Photon Source (TPS). The momentum compaction can be positive or negative and its value can be reduced by more than two orders of magnitude. In this paper, we discuss variable low alpha lattice optics, its beam dynamics issues, the measured momentum compaction and bunch lengths as well as beam orbit stability issues, etc., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

The Taiwan Photon Source (TPS) is currently operated in top-up mode for users. In order to improve the stability of the synchrotron light source, vibrations related to the vacuum system have been investigated and improved by turning off pumping systems and reducing the flow rate in chamber cooling water circuits. In this paper, vibrations in different vacuum chambers with normal cooling water condition were investigated, their sources were recorded and clarified and properties of different materials for water tubes were also compared., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

Pulse magnets are used in storage ring injection kickers. The waveform of the the four kickers have strong relation with injection efficiency. A slightly offset of waveform may cause the four kickers mismatched, which would lead to storaged beam loss and decrease injection efficiency. In order to define the peak value and timing of the half-sine waveform which has noises interfering diagnosis, a curve-fitting method was introduced to monitor and fine-tuning the waveform. The waveforms' data are also archived for reference in case of replacing power supplies. By using this method, it helps to retain a consistent injection efficiency after the power supplies maintenance or replacement., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

Accelerator-based coherent THz radiation sources are being studied with the NSRRC high brightness photoinjector which has been installed in the Accelerator Test Area (ATA) recently. This injector is equipped with a laser-driven photocathode rf gun and a 5.2-m long S-band traveling-wave linac for beam acceleration. A few tens MeV, ultrashort bunches of ~100 fs bunch length can be produced from the injector by velocity bunching technique. Tunable narrow-band THz coherent undulator radiation (CUR) can be generated from a U100 planar undulator when it is driven by such beam. One the other hand, broadband THz coherent transition radiation (CTR) generated by passing this beam through a metallic foil is used for determination of bunch length by autocorrelation technique. The experimental setup and results are presented in this paper., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

To find out abnormal situations of the machine for preventive maintenance or machine trip tracking or instability source diagnosis, a large amount of operating data in an accelerator is thus can be used to build a series data analysis program. When the archived data is classified accordingly, the standard deviation (STD), peak-to-peak value and other statistic indexes within the inspection time zone by the belonging families can be used to point out the especially abnormal signals. The analysis program adopts the techniques of parallel calculation and memory optimization to greatly reduce the time for data transmission and analysis and also displays the correlation signals to opera-tors for deeper analysis. This paper illustrated a simple yet effective method for quickly identifying a not-so-obscure hardware issue by simply using a personal computer (PC)., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

In order to provide short-pulse radiation for pump-probe experiments and coherent radiation for THz/IR measurements, we develop low alpha lattices to reduce the momentum compaction factor from nominal operation values 2.4*10⁻⁴ to 2.6*10-5 or lower. The corresponding bunch length at 2.8 MV RF voltage and zero current are from 10.78 ps to 3.55 ps or less. In the low alpha operations, the bunch lengthening as a function of bunch current, the orbit drift and noise enhancements as well as rf stability effect are observed. In this report we will present our studies on the lattice design, optics correction, beam parameters measurements and alpha measurements., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

We developed and tested lattice with lower momentum compaction factor (low alpha) in TPS (Taiwan Photon Source) recently. Operating low alpha lattice can provide picosecond bunch length for time-resolved research and coherent IR/THz synchrotron light. The bunch length around 2.5 picosecond rms was measured by a streak camera* in low alpha mode while operating in the routine users mode** it was around 10 picosecond. This paper presents the related processes and measurements., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

Failure analysis during TPS users operation is im-portant to improve the performance of the TPS storage ring. In this report, we discuss the particular radiation dose patterns, relevant to different beam trips, and the development of a tool to help us analyse this dose distri-bution. We will use this analysing tool to train our ability for future failure analysis to shorten the time it takes to find the problem., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

An optimized injection efficiency is related to a perfect match between the pulsed magnetic fields in the storage ring and transfer line extraction in the TPS. However, misalignment errors, hardware output errors and leakage fields are unavoidable. We study the influence of injection transients on the stored TPS beam and discuss solutions to compensate these. Related simulations and measurements will be presented., Proceedings of the 8th Int. Particle Accelerator Conf., IPAC2017, Copenhagen, Denmark

The TPS commissioning period is from August 2014 to March 2016. The experience of phase I [1] (bare lattice 2014.8~2015.3) and phase II [2,3] (SRF and insertion devices 2015.9~2016.3) commissioning is overviewed. Taiwan Photon Source (TPS) started user operation in March 2016. The delivery user time reached 3211 hours. The continuous improvements of integrated accelerator performance are described and future developments are discussed., Proceedings of the 8th Int. Particle Accelerator Conf., IPAC2017, Copenhagen, Denmark

The Taiwan Photon Source (TPS) is the latest generation of 3 GeV synchrotron light source which subsystem includes magnet, power supply, vacuum, RF system, insertion device, control system, etc. The operating procedures and checking items are complex. To speed up the machine start-up and shut-down procedures, check the system's status, and prevent misoperation, we summarize the procedures for routine operation and develop the integrated control interface, which concentrates most machine information and control functions into a single window. This interface clearly indicates the machine status and improves operational efficiency., Proceedings of the 8th Int. Particle Accelerator Conf., IPAC2017, Copenhagen, Denmark

A part of high brightness photo-injection (HBI) project at NSRRC is intending to adopt Coherent Transition Radiation (CTR) and Coherent Undulator Radiation (CUR) to generate THz radiation with an ultrashort electron bunch. Such high intensity THz sources allow the THz spectrum to be conducted easily with a THz interferometer and a Golay cell detector. Furthermore, the radiation spectrum carries information of the electron distribution which allows ultrashort electron bunch length measurements. For verifying correct measuring procedure during the CTR and CUR experiments, a conventional THz radiation generated by optical rectification from a ZnTe crystal has been performed. The produced THz pulse was sent into a Michelson interferometer which is designed for the autocorrelation of the intense, sub-mm and mm-wavelength, spatially-coherent radiation pulses. The THz spectrum can be further obtained from the interferogram by the Fourier transform process. In such way, the THz spectrum can be investigated if the result is satisfactory and can be applied on the THz CTR and CUR experiments for the next step., Proceedings of the 8th Int. Particle Accelerator Conf., IPAC2017, Copenhagen, Denmark

The 3 GeV Taiwan Photon Source has been routinely operated for public users since September 2016. Orbit reproducibility and stability are critical for the quality of user experiments. Ambient temperature variations and earth tides can cause a change in circumference, changing in turn the beam energy, and orbit drift. Therefore both, orbit correction and rf frequency adjustments are necessary to keep the ring circumference constant. A Fast Orbit Feedback (FOFB) system combined with rf frequency correction deduced from the fast corrector strengths is applied to the FOFB routine. The correlation between the measured frequency variation with ambient temperature and earth tides is also reported in this article., Proceedings of the 8th Int. Particle Accelerator Conf., IPAC2017, Copenhagen, Denmark

The Taiwan Photon Source (TPS), a 3-GeV third generation synchrotron light source, was commissioned in 2014 December and is now currently operated in top-up mode at 300mA for users. During the past two years, the machine was completed to meet design goals with among others the installation of superconducting cavities (SRF), the installation of insertion devices (ID) and the correction of vacuum chamber structure downstream from the IDs. The design goal of 500mA beam current was achieved with a total accumulated beam dose of more than 1000Ah, resulting in three orders of magnitude reduction of out-gassing. As the beam current was increased, a few vacuum problems were encountered, including vacuum leaks, unexpected pressure bursts, etc. Vacuum related issues including high pressure events, lessons learned and operational experience will be presented and discussed in this paper., Proceedings of the 8th Int. Particle Accelerator Conf., IPAC2017, Copenhagen, Denmark

A stable, reliable and well-calibrated beam position monitor (BPM) system is essential for the operation of accelerators. At newly constructed Taiwan Photon Source (TPS), it not only helps us to determine the accelerator parameters, such as Twiss parameters and tune, but also to avoid the damage on accelerator instruments caused by high-energy particle beams or radiation. In this study, we demonstrate a new BPM calibration scheme at TPS storage ring. To excite the electron beams inside accelerator beam pipe by one horizontal or vertical corrector magnet, we measure the response of analog-to-digital converter (ADC) of each BPM pick-up electrodes with different lateral positions and beam currents. Depending on the measured ADC responses, we calibrated the beam position monitor system. Simultaneously, because of limited preparation time after every long shutdown, we are looking for a fast algorithm to ensure the measurement could be done easily and finished as quickly as possible., Proceedings of the 8th Int. Particle Accelerator Conf., IPAC2017, Copenhagen, Denmark

The Taiwan Photon Source (TPS) has been successfully commissioned and has reached now stable operation. Now, the machine must be turned off routinely for week-ly maintenance. While following standard machine turn-on procedures for now, we have developed an automatic turn-on program to accelerate operation, for automatic system status checks and to prevent human errors. The turn-on program process flow includes: turn-on of the LTB (linac to booster transport line), the BTS (booster to storage ring transport line), the SR (storage ring), the BR (booster ring) power supplies and BR&SR pulsers as well as degaussing magnets, turning on the BR&SR RF sys-tems, activating the linac electron source, opening all insertion device (ID) gaps to their parking positions, set-ting all ID phases to zero, controlling all front ends (FEs) and loading the desired machine lattice. Individual pro-cedures can be executed alone depending on the desired practical situation. Experience so far shows, that it takes about 30 minutes to proceed from tunnel safety search to the injection ready state of the light source, including a 20 minute period for magnet degaussing., Proceedings of the 8th Int. Particle Accelerator Conf., IPAC2017, Copenhagen, Denmark

The High brightness injector project at NSRRC aims to develop a100 MeV photo-injector system for light source R&D at NSRRC. This photo-injector system equipped with a photocathode rf gun, a solenoid for emittance compensation, an S-band linac as well as various beamdiagnostic tools. In the beginning of this project, the photocathode rf gun was installed in the booster room of TLS at NSRRC. The normalized beam transverse emittance is 5.5 mm-mrad at ~250 pC with Gaussian laser pulse. Recently, a 100 MeV photo-injector system is being installed in the 38 m by 5 m tunnel of the NSRRC linac test laboratory. The rf gun, the 35 MW high power microwave system and a 5.2 m lina has been set up. The UV driver laser system will be set up in the new temperature controlled clean room in the linac test laboratory. For initial beam test, some beam diagnostic tools are considered. They are presented and discussed in this paper., Proceedings of the 4th International Beam Instrumentation Conference, IBIC2015, Melbourne, Australia

A High brightness injector at NSRRC is built for a VUV/THz free electron laser (FEL) facility and light source R&D. This injector with a photocathode rf gun with a solenoid for emittance compensation, a UV laser system, a 5.2 m S-band linac as well as various beam diagnostic tools has been installed in the linac test laboratory. The main goal is to produce beams with emittance smaller than 1 mm-mrad at energy of ~100 MeV. The other goal is to compress bunches to ~100 fs with charge of 100 pc and energy of ~30 MeV. In this contribution, an overview of the commissioning results of the photocathode rf gun and the laser system will be given. The first beam observation downstream the lianc will be presented in this paper., Proceedings of the 7th Int. Particle Accelerator Conf., IPAC2016, Busan, Korea

To acquire precise beam orbits from beam position monitors (BPMs) in storage ring is one of the most significant diagnosis to measure beam parameters. However, the precise spectrum analyses from BPM data acquisitions such as betatron tune, dynamics aperture and frequency map '..etc. that are depended on more accurate discrete Fourier transform (DFT) or the fast Fourier transform (FFT). A method of the fast Fourier transform correction (FFTc) was employed for the more accurate spectrum measurement in Taiwan Photon Source (TPS). We perform the accuracy and error analyses of this method from some spectral lines in two window functions. And the precise spectrum for betatron tune measurements and related results will be presented., Proceedings of the 7th Int. Particle Accelerator Conf., IPAC2016, Busan, Korea

The Taiwan Photon Source (TPS) is a low-emittance 3-GeV light source at Natioal Synchrotron Radiation Research Center, next to the Taiwan Light source (1.5 GeV). On March 26, 2015, the TPS storage ring with two 5-cell PETRA cavities has successfully operated in 100 mA in top-up mode without the installation of insertion devices (IDs). To reach the design goal of 500 mA, the machine was shut down for 5 months to replace PETRA cavitites with superconducting RF (SRF) cavities and to install 10 IDs: 7 in-vacuum undulators (IU) and 3 elliptically polarized undulators (EPU). The commissioning of TPS storage ring with SRF cavities and IDs began in Sep. 2015. In this paper, we present our results and proceedures of ID commissioning., Proceedings of the 7th Int. Particle Accelerator Conf., IPAC2016, Busan, Korea

The impedance at Taiwan Photon Source was investigated. The effects of bunch current such as a tune change, a synchronous phase shift and a bunch lengthening under operation conditions at various stages were measured; the machine impedances were deduced. This report presents the results with insertion devices in various configurations., Proceedings of the 7th Int. Particle Accelerator Conf., IPAC2016, Busan, Korea

The traditional alarm systems usually set up/low limit for various signals. When the acquired values exceed the limits, the alarm system would be activated. The proposed system in this article can focus on various possible events with many kinds of signals for response judgments. During alarm calling period, data can also be announced and recorded. The system can also monitor various events according to different time shifts. Integrating LabVIEW, mobile phone, AT-command and Bluetooth communication, the system can handle factory broadcast, sending E-mail and SMS message. The above sound and words messages can be set directly at the home-made software interface. The new intelligent alarm system can eliminate the procedure made by man with the added event recording, system stability improvement and debugging function in wider application fields., Proceedings of the 7th Int. Particle Accelerator Conf., IPAC2016, Busan, Korea

Taiwan Photon source (TPS) is in its first stage commissioning in 2014-2015. The vacuum systems of TPS were installed for commissioning since August 2014. After four months performance testing and subsystem integration, the commissioning of booster ring began on 12 December and then the first 3 GeV beam was stored on 31 December. 100mA beam current, 35Ah accumulated beam dose was archived in March 2015 before machine shut down. The average pressure in storage ring is 2.8×10⁻⁸ Pa before commissioning, rising to 1.33×10-7 Pa with 100mA beam current. In 35Ah accumulated beam dose, the target of beam cleaning effect has reached to 8.92×10-10 Pa/mA. The vacuum performance, experience and events during commissioning will be presented in this paper., Proceedings of the 6th Int. Particle Accelerator Conf., IPAC2015, Richmond, VA, USA

The Response Surface Methodology (RSM), is used to study the optimization process of magnet AC in the booster for Taiwan Light Source (TLS) in National Synchrotron Radiation Research Center (NSRRC). A study model was constructed based on the Artificial Neural Network (ANN) theory. The theoretical model and optimization procedure were both implemented to evaluate the model. The details of the study will be reported in this paper., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany

A high brightness photo-injector is under development for single pass FEL research at NSRRC. The gun test facility (GTF) equipped with a photocathode rf gun a compensation solenoid, a S-band high power pulse klystron as well as a UV driver laser has been constructed for testing the photocathode rf gun. The gun is fabricated in house and being tested at the GTF. Since the transverse emittance is a key property of the electron beam from the rf gun, multi-slit method is used to characterize the transverse emittance of the electron beam. Another key property of the electron beam is bunch length. An S-band three-cell deflecting cavity is designed to measure the bunch length. The setup and results of emittance measurement as well as the structure design of the deflecting cavity is reported in this contribution., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany

The oncoming completion of Taiwan Photon Source is closely constructed beside Taiwan Light Source (TLS). Few civil works are continuously under construction. Building the measurement, recording and analysis platform of software and hardware is the one of the main directions of operation group. To diagnose the instability problem of the light source, the external influence must be eliminated. One of the factors causing the instability is the physical vibration. Vibration measurement helps to evaluate if newly installed equipments are suited for adding on or the influence of the earthquake to the stability of TLS and to improve the light source quality for users. Software has been developed to provide assistance to do some preliminary diagnoses at TLS. In this article, some actual cases in routine operation are also presented., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany

A 25-30 MeV S-band linac system that equipped with thermionic cathode rf gun is being constructed at NSRRC for generation of ultrashort relativistitic electron beam. According to simulation studies, high quality GHz repetition rate electron pulses of about 50 pC as short as few tens fsec can be produced. This injector system will be used as the driver for experiments on fsec head-on inverse Compton scattering X-ray source and high power wake field microwave sources. The progress of our construction work will be presented., Proceedings of the 1st International Particle Accelerator Conference, IPAC2010, Kyoto, Japan