Xiaobiao Huang
SLAC National Accelerator Laboratory
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Featured researches published by Xiaobiao Huang.
ieee particle accelerator conference | 2007
Xiaobiao Huang; J. Safranek; Jeff Corbett; Y. Nosochkov; Jim Sebek; Andrei Terebilo
In the interest of obtaining shorter bunch length for shorter X-ray pulses, we have developed a low-alpha operational mode for SPEAR3. In this mode the momentum compaction factor is reduced by a factor of 21 or more from the usual achromat mode by introducing negative dispersion at the straight sections. We successfully stored 100 mA with the normal fill pattern at a lifetime of 30 hrs. The bunch length was measured to be 6.9 ps, compared to 17 ps in the normal mode. In this paper we report our studies on the lattice design and calibration, orbit stability, higher order alpha measurement, lifetime measurement and its dependence on the sextupoles, injection efficiency, longitudinal stability and bunch lengths.
Physical Review Special Topics-accelerators and Beams | 2015
Xiaobiao Huang; James Safranek
We propose to optimize the nonlinear beam dynamics of existing and future storage rings with direct online optimization techniques. This approach may have crucial importance for the implementation of diffraction limited storage rings. In this paper considerations and algorithms for the online optimization approach are discussed. We have applied this approach to experimentally improve the dynamic aperture of the SPEAR3 storage ring with the robust conjugate direction search method and the particle swarm optimization method. The dynamic aperture was improved by more than 5 mm within a short period of time. Experimental setup and results are presented.
ieee particle accelerator conference | 2007
Jeff Corbett; A.S. Fisher; Xiaobiao Huang; J. Safranek; J. Sebek; A. Lumpkin; F. Sannibale; W. Mok
A series of bunch length measurements were made in SPEAR3 for two different machine optics. In the achromatic optics the bunch length increases from the low-current value of 16.6 ps rms to about 30 ps at 25 ma/bunch yielding an inductive impedance of -0.17 Omega. Reducing the momentum compaction factor by a factor of ~60 [1] yields a low-current bunch length of ~4 ps rms. In this paper we review the experimental setup and results.
Archive | 2010
K. Bane; Kirk Bertsche; Y. Cai; Alex Chao; Willian Corbett; J. Fox; Robert Hettel; Xiaobiao Huang; Z. Huang; Cho-Kuen Ng; Y. Nosochkov; Sasha Novokhatski; Thomas Radedeau; T. Raubenheimer; Claudio Rivetta; J. Safranek; J. Seeman; J. Stöhr; Gennady Stupakov; Lanfa Wang; Min-Huey Wang
Over the past year, we have worked out a baseline design for PEP-X, as an ultra-low emittance storage ring that could reside in the existing 2.2-km PEPII tunnel. The design features a hybrid lattice with double bend achromat (DBA) cells in two arcs and theoretical minimum emittance (TME) cells in the remaining four arcs. Damping wigglers are used to reduce the horizontal emittance to 86 pm-rad at zero current for a 4.5 GeV electron beam. At a design current of 1.5 A, the horizontal emittance increases, due to intrabeam scattering, to 164 pm-rad when the vertical emittance is maintained at a diffraction limited 8 pm-rad. The baseline design will produce photon beams achieving a brightness of 10{sup 22} (ph/s/mm{sup 2}/mrad{sup 2}/0.1% BW) at 10 keV in a 3.5-m conventional planar undulator. Our study shows that an optimized lattice has adequate dynamic aperture, while accommodating a conventional off-axis injection system. In this report, we present the results of study, including the lattice properties, nonlinear dynamics, intra-beam scattering and Touschek lifetime, RF system, and collective instabilities. Finally, we discuss the possibility of partial lasing at soft X-ray wavelengths using a long undulator in a straight section.
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment | 2016
Xi Yang; Xiaobiao Huang
Abstract We propose a method to simultaneously correct linear optics errors and linear coupling for storage rings using turn-by-turn (TbT) beam position monitor (BPM) data. The independent component analysis (ICA) method is used to isolate the betatron normal modes from the measured TbT BPM data. The betatron amplitudes and phase advances of the projections of the normal modes on the horizontal and vertical planes are then extracted, which, combined with dispersion measurement, are used to fit the lattice model. The fitting results are used for lattice correction. The method has been successfully demonstrated on the NSLS-II storage ring.
Journal of Synchrotron Radiation | 2014
Xiaobiao Huang; Thomas Rabedeau; James Safranek
Approaches to generating short X-ray pulses in synchrotron light sources are discussed. In particular, the method of using a superconducting harmonic cavity to generate simultaneously long and short bunches in storage rings and the approach of injecting short bunches from a linac injector into a storage ring for multi-turn circulation are emphasized. If multi-cell superconducting RF (SRF) cavities with frequencies of ∼1.5 GHz can be employed in storage rings, it would be possible to generate stable, high-flux, short-pulse X-ray beams with pulse lengths of 1-10 ps (FWHM) in present or future storage rings. However, substantial challenges exist in adapting todays high-gradient SRF cavities for high-current storage ring operation. Another approach to generating short X-ray pulses in a storage ring is injecting short-pulse electron bunches from a high-repetition-rate linac injector for circulation. Its performance is limited by the microbunching instability due to coherent synchrotron radiation. Tracking studies are carried out to evaluate its performance. Challenges and operational considerations for this mode are considered.
ieee particle accelerator conference | 2007
J. Safranek; W.J. Corbett; Robert Hettel; Xiaobiao Huang; Y. Nosochkov; Jim Sebek; Andrei Terebilo
The SPEAR3 [1,2] storage ring at Stanford Synchrotron Radiation Laboratory has been delivering photon beams for three years. We will give an overview of recent and ongoing accelerator physics activities, including 500 mA fills, work toward top-off injection, long-term orbit stability characterization and improvement, fast orbit feedback, new chicane optics, low alpha optics & short bunches, low emittance optics, and MATLAB software. The accelerator physics group has a strong program to characterize and improve SPEAR3 performance.
Synchrotron Radiation News | 2013
James Safranek; Jeff Corbett; Xiaobiao Huang; Tom Rabedeau; J. Schmerge; Jim Sebek
The SPEAR3 storage ring at SLAC National Accelerator Laboratory, Stanford Synchrotron Radiation Lightsource, is delivering beam in a short-pulse, low-α operational mode. In order to deliver short photon pulses, the stored current in SPEAR3 must be reduced. In low-α mode, we presently deliver 100 mA total current with bunch lengths of 15 psec FWHM, compared to our standard operations with 500 mA and 46 psec FWHM bunch lengths. It is possible to deliver still shorter pulses at lower current. The low-α beam is stored in four bunch trains, interleaved with up to four “camshaft” timing bunches for pump-probe experiments. This simultaneously provides short pulses for timing experiments while ensuring 100 mA for experiments at other beamlines.
Journal Name: ICFA Beam Dyn.Newslett.44:49-60,2007; Journal Volume: 44 | 2011
Greg Portmann; Berkeley Lbl; J. Safranek; Xiaobiao Huang
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment | 2013
Xiaobiao Huang; Jeff Corbett; James Safranek; J. Wu