| Paper | Title | Page |
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| THPAB093 | Synchronization of a Photo-Injector and a High Power Laser With Independent Clocks | 3935 |
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Funding: LAL/IN2P3/CNRS and Université Paris-Sud The plasma acceleration project ESCULAP (ElectronS CoUrts pour L'Acc\'el\'eration Plasma) aims at studying electrons injection into a laser plasma accelerator. This requires the injection of short electron bunches generated by the photo injector PHIL (Photo injector at LAL) into a plasma wave by the high power femtosecond Laser LASERIX. As a first step we have studied how to synchronize PHIL and LASERIX. As these two machines had not been initially designed to work together, simple synchronization solutions were not available. We detail here the synchronisation scheme that we have tested and the experimental results obtained. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB093 | |
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| THPAB105 | Design and Operation of the Integrated 1.3 GHz Optical Reference Module with Femtosecond Precision | 3963 |
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| In modern Free-Electron Lasers like FLASH or the European XFEL, the short and long-term stability of RF reference signals gains in importance. The requirements are driven by the demand for short FEL pulses and low-jitter FEL operation. In previous publications, a novel, integrated Mach-Zehnder Interferometer based scheme for a phase detector between the optical and the electrical domain was presented and evaluated. This Laser-to-RF phase detector is the key component of the integrated 1.3 GHz Optical Reference Module (REFM-OPT) for FLASH and the European XFEL. The REFM-OPT will phase-stabilize 1.3 GHz RF reference signals to the pulsed optical synchronization systems in these accelerators. Design choices in the final hardware configuration are presented together with measurement results and a performance evaluation from the first operation period in the European XFEL. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB105 | |
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| THPAB108 | Femtosecond Optical Synchronization System for the European XFEL | 3969 |
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| Accurate timing synchronization on the femtosecond timescale is an essential installation for time-resolved experiments at free-electron lasers (FELs) such as FLASH and the upcoming European XFEL. Conventional RF timing systems suffer from RF attenuation for such long distances and have reached to date a limit for synchronization precision of around 100 femtoseconds. An optical synchronization system is used at FLASH and is based on the distribution of femtosecond laser pulses over actively stabilized optical fibers. The upcoming European XFEL has raised the demands due to its large number of stabilized optical fibers and a length of 3400 m. The increased lengths for the stabilized optical fibers necessitated major advancement in precision to achieve the requirement of less than 10 femtosecond precision. This paper reports on the status of the laser-based synchronization system at the European XFEL. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB108 | |
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| THPAB109 | Fs Level Laser-to-RF Synchronization at REGAE | 3972 |
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| The Relativistic Electron Gun for Atomic Exploration (REGAE) is a unique linear accelerator capable of producing ultrashort (~ 10 fs) electron bunches for studying fast processes in matter by means of ultrafast electron diffraction (UED) experiments. Additionally, REGAE is suitable for upcoming external injection experiments for laser wakefield acceleration (LWFA). In order to carry out both mentioned experiments, it is crucial to achieve fs level stability in terms of Laser-to-RF synchronization. In this paper we present an advanced laser-to-RF synchronization scheme based on integrated Mach-Zehnder modulator. The setup demonstrated the Titanium Sapphire photo-injector laser synchronization with 11 fs (rms) precision in the bandwidth up to 100 kHz. Long term timing drift measurements showed unprecedented peak-to-peak stability of 31 fs (7 fs rms) over 43 hours of measurement time. In addition, AM-PM coefficient of the MZM based laser-to-RF synchronization setup has been evaluated and showed a factor of 10 improved performance compared to conventional direct conversion based laser synchronization setup. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB109 | |
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| THPAB110 | Custom Optomechanics for the Optical Synchronization System at the European XFEL | 3976 |
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| Free-electron-lasers like the upcoming European XFEL demand highly reliable optical synchronization in range of few femtoseconds. The well known optical synchronization system at FLASH had to be re-engineered to meet XFEL requirements comprising demands like ten times larger lengths and raised numbers of optically synchronized instruments. These requirements directly convert to optomechanical precision and have yielded in a specialized design accounting for economical manufacturing technologies. These efforts resulted in reduced spatial dimensions, improved optical repeatability, maintainability and even reduced production costs. To account for thermal influences the heart of the optical synchronization system is based on an optical table made out of SuperInvar. To fully exploit its excellent thermal expansion coefficient, mechanical details need to be taken into account. This work presents the design and its realization of the re-engineered optomechanical parts of the optical synchronization system, comprising mounting techniques, link stabilization units and optical delay lines for high drift suppression. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB110 | |
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| THPAB111 | Sub-Femtosecond Jitter Ultra High Performance Oscillators for Accelerator Timing | 3979 |
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| Extremely stable RF-Sources are at the heart of Electron Beam Accelerators and impact beam quality and beam energy. Jitter requirements on those sources are very tight and linked to the quest of ever decreasing (XFEL) laser pulse length, currently in the tens of femtoseconds. For the Pohang Accelerator Laboratory in Pohang/Korea, a 2.856GHz phase-lockable oscillator with a jitter performance of 0.8fS (10kHz..10MHz) was developed and deployed, together with a master oscillator that supplies rubidium-stabilized 476MHz for synchronization. In terms of phase noise, these 2.856GHz oscillators exhibit -125dBc/Hz@1kHz, -145dBc/Hz@10kHz and -165dBc/Hz@100kHz offset, while reaching a noise floor of -180dBc/Hz. Using the same technology of a dielectric resonator oscillator, a 3.9GHz source was developed for the European XFEL at DESY/Hamburg, achieving 0.3fS (10kHz/10MHz). Phase noise is down to -125dBc/Hz@1kHz, -155dBc/Hz@10kHz and -175dBc/Hz@100kHz offset, with a noise floor of -180dBc/Hz. The strategy of designing ultra low phase-noise sources with dielectric resonators is outlined, and challenges and limitations within the oscillator design, but also measurement technology are presented. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB111 | |
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| THPAB113 | Time Synchronization for Distant IOCs of the SuperKEKB Accelerators | 3982 |
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| The time synchronization for multi CPU system is always a problem to be worried. The control system of accelerator is no exception since it consists of a lot of CPUs located among large area distantly. The problem appears conspicuously when the beam is aborted. Usually, several hardware show abort signals in one beam abort event. However it is difficult to know which is the source of beam abort and which issues an abort signal under the influence of original failure. We introduce the time synchronization system of the SuperKEKB collider which choose EPICS as the control software. The system utilize Event Timing System and synchronizes the EPICS general time for I/O controllers located distantly. The accuracy of synchronization is around 10ns. It is the excellent performance in terms of synchronization of CPU time. The all abort channels of SuperKEKB are synchronized their issued time. Besides they synchronize with also the injector linac which is operated with the different control system in different network. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB113 | |
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| THPAB118 | Stabilization of Timing System Operation of J-PARC Linac and RCS | 4000 |
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| At the timing system for J-PARC Linac and Rapid Cycling Synchrotron (RCS), the distribution of timing information (beam tag, type, etc.) and the monitoring and control of timing system are performed via the reflective memory (RFM). The more 10 years elapsed after operation start of J-PARC. Therefore, it is concerned about the occurrence of malfunctions due to time-related deterioration of the devices of timing system. Especially, the malfunctions of a management computer to monitor and control the all timing devices and RFMs to configure the timing system data network have a significant impact. Then, the management computer was renewed and PCI-Express RFMs are installed instead of PCI RFMs. However, after renewal computer, the trouble by data corruption of RFM network was happened anew. In this paper, the contents and the results our cause investigation of data corruption and those of the measures employed for stabilizing the timing system operation are presented. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB118 | |
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| THPAB128 | Beam Arrival Time Analisis Based on CBPM at DCLS | 4023 |
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| Dalian Coherent Light Source is the first high gain free electron lasers (FEL) user facility in China, which is dedicated at extreme ultraviolet (EUV) spectral regime of 150-50nm for various scientific fields. In its undulator section, the beam-line was equipped with ten pair of high-precision cavity beam position monitor (CBPM), which can be used for beam position and beam arrival time (BAT) measurement. Based on this, we have done some preliminary research about the beam fight time with the reference cavities of CBPMs for the future research on BAT. In this paper, we presented the scheme of the beam fight time (BFT) research, analyzed the results, and evaluated the consistency and stability of BFT. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB128 | |
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