| Paper |
Title |
Page |
| TOPB003 |
Progress in Large-Scale Femtosecond Timing Distribution and RF-Synchronization
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284 |
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- F.X. Kaertner, H. Byun, J. Chen, F J. Grawert, F.O. Ilday, J. Kim, A. Winter
MIT, Cambridge, Massachusetts
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For future advances in accelerator physics in general and seeding of free electron lasers (FELs) in particular, precise synchronization between low-level RF-system, photo-injector laser, seed radiation as well as potential probe lasers at the FEL output is required. We propose a modular system based on optical pulse trains from mode-locked lasers for timing distribution and timing information transfer in the optical domain to avoid detrimental effects due to amplitude to phase conversion in photo detectors. Synchronization of various RF- and optical sub-systems with femtosecond precision over distances of several hundred meters can be achieved. First experimental results and limitations of the proposed scheme for timing distribution are discussed.
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| MPPP034 |
Collective Effects in the TLS Storage Ring after the Installation of Superconducting RF Cavity
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2360 |
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- P.J. Chou, J. Chen, K.-T. Hsu, C.-C. Kuo, C. Wang, M.-H. Wang
NSRRC, Hsinchu
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A superconducting rf cavity designed by Cornell University was installed in the storage ring at Taiwan Light Source in December of 2004. The purpose of rf system upgrade is to achieve a stored beam current of 400 mA without collective instabilities caused by high-order-modes of rf cavities. Beam measurements related to collective effects are performed. Results are compared with those measured prior to the rf system upgrade. Theoretical studies on collective effects after the rf upgrade are also presented.
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| MPPT032 |
Construction and Performance of Superconducting Magnets for Synchrotron Radiation
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2218 |
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- C.-S. Hwang, C.-H. Chang, C.-K. Chang, H.-P. Chang, C.-T. Chen, H.-H. Chen, J. Chen, J.-R. Chen, Y.-C. Chien, T.-C. Fan, G.-Y. Hsiung, K.-T. Hsu, S-N. Hsu, M.-H. Huang, C.-C. Kuo, F.-Y. Lin
NSRRC, Hsinchu
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Two superconducting magnets, one wavelength shifter (SWLS) with a field of 5 T and one wiggler (SW6) with a field of 3.2 T, were constructed and routinely operated at NSRRC for generating synchrotron x-rays. In addition, three multipole wigglers (IASW) with fields of 3.1 T will be constructed and installed each in the three achromatic short straight sections. A warm beam duct of 20 mm inner gap and a 1.5 W GM type cryo-cooler were chosen for the SWLS to achieve cryogen-free operation. For the SW6, a cold beam duct of 11 mm inner gap was kept at 100 K temperature and no trim coil compensation is necessary for its operation. Meanwhile, no beam loss was observed when the SW6 was quenched. A cryogenic plant with cooling power of 450 W was constructed to supply the liquid helium for the four superconducting wigglers. The design concept, magnetic field quality, the commissioning results, and the operation performance of these magnets will be presented.
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| RPAE049 |
Revision of Booster to Storage Ring Transport Line Design and Injection Scheme for Top-Up Operation at NSRRC
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3085 |
| |
- M.-H. Wang, H.-P. Chang, J. Chen, J.-R. Chen, K.-T. Hsu, C.-C. Kuo, G.-H. Luo
NSRRC, Hsinchu
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In order to help the operation of constant current, the optics of booster to storage ring transport line (BTS) design is reinvestigated. 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 1.2μsecond to 2.0μsecond. The injection scheme is reviewed and the effects of the kicker error on both injected beam and stored beam are investigated and shown in this report.
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| RPPT038 |
Phase Noise Characteristics of Fiber Lasers as Potential Ultra-Stable Master Oscillators
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2521 |
| |
- A. Winter, P. Schmüser
Uni HH, Hamburg
- J. Chen, F.O. Ilday, F.X. Kaertner, J. Kim
MIT, Cambridge, Massachusetts
- H. Schlarb
DESY, Hamburg
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Fourth-generation light sources, such as the European X-Ray free electron laser facility (XFEL) require timing signals distributed over distances of the order of kilometers with a timing jitter in the order of femtoseconds. The master clock for the proposed optical distribution system must operate with exceptionally low timing jitter. A promising approach is the use of a mode-locked laser that generates ultrastable pulses which are distributed via timing stabilized fiber links. Candidates for the pulse source are mode-locked Erbium doped fiber lasers, featuring very low high frequency noise. In this paper, we present a study of the phase noise of various fiber lasers in view of their applicability as laser-based master oscillators for femtosecond timing distributions.
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| RPPT039 |
Stabilized Optical Fiber Links for the XFEL
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2589 |
| |
- A. Winter
Uni HH, Hamburg
- J. Chen, F J. Grawert, F.O. Ilday, F.X. Kaertner, J. Kim
MIT, Cambridge, Massachusetts
- H. Schlarb, B. Schmidt
DESY, Hamburg
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The timing synchronization scheme for the European X-Ray free electron laser facility (XFEL) is based on the generation and distribution of sub-picosecond laser pulses with actively stabilized repetition rate which are used to synchronize local RF oscillators. An integral part of the scheme is the distribution of the optical pulse stream to parts of the facility via optical fiber links. The optical path length of the fiber has to be stabilized against short-term and long-term timing jitter due to environmental effects, such as temperature drifts and acoustic vibrations, to better than 10 fs for distances ranging from tens of meters to several kilometers. In this paper, we present first experimental results for signal transmission through a km-long fiber link with femtosecond stability.
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