PAC07 - List of Authors (Huang, X.)

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Huang, X.

Paper	Title	Page
TUZAAB03	Emittance Measurement and Modeling for the Fermilab Booster	799
	X. Huang S.-Y. Lee IUCF, Bloomington, Indiana K. Y. Ng Fermilab, Batavia, Illinois
	Funding: DOE/NSF We systematically measured the emittance evolution of a fast cycling proton accelerator on a turn-by-turn basis under various beam intensities via an ionization profile monitor (IPM). The vertical emittance growth rate was derived and phenomenologically analyzed. The transverse and longitudinal components in the horizontal beam size were separated by making use of their different evolution behaviors. The quadrupole mode beam size oscillation after transition crossing is also studied and explained. We found a considerable space-charge-induced emittance growth rate component in the vertical plane but not as much for the horizontal plane. We carried out multiparticle simulations to understand the mechanism of space-charge-induced emittance growth. The major sources of emittance growth were found to be the random skew-quadrupole and dipole field errors in the presence of large space-charge tune spread. PRSTAB 9, 014202 (2006)
	Slides
TUPMS050	Simulation of Ultra-Short Pulses in a Storage Ring	1305
	X. Huang
	Simulation study was performed with the tracking code Elegant [M. Borland, APS Report LS-287] to show beam quality evolution for a short, intense electron bunch after being injected to the SPEAR3 storage ring. The electron bunch with an intensity of 1mA (0.78nC) and a length of nearly 1ps (FWHM) is found to degrade rapidly due to coherent synchrotron radiation (CSR) which causes large uneven longitudinal phase space distortion. The bunch length remains short and the longitudinal line density remains smooth for about 10 turns. For such a beam to circulate in the ring, a total of 10MV rf power is needed to compensate for the energy loss. * M. Borland, APS Report LS-287
TUPMS051	Low Alpha Mode for SPEAR3	1308
	X. Huang W. J. Corbett, Y. Nosochkov, J. A. Safranek, J. J. Sebek, A. Terebilo SLAC, Menlo Park, California
	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 30hrs. The bunch length was measured to be 6.9ps, compared to 17ps 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 and bunch lengths.
TUOCAB01	A New Code for Orbit Response Matrix Analysis	804
	L. Yang X. Huang SLAC, Menlo Park, California S.-Y. Lee IUCF, Bloomington, Indiana B. Podobedov BNL, Upton, Long Island, New York
	Funding: NSF PHY-0552389, DOE DE-FG02-92ER40747 The Orbit Response Matrix (ORM) has been successfully used extensively in accelerator modeling. However, in many cases, the existing codes can not find a correct model. We develop a new code that solve the convergence and coupling problems. We test our code by carrying out systematic study of accelerator models. Effects measurement errors and the completeness of information will be addressed in this study. Possible inclusion of phase information will be discussed.
	Slides
TUPMS055	SPEAR3 Accelerator Physics Update	1311
	J. A. Safranek W. J. Corbett, S. M. Gierman, R. O. Hettel, X. Huang, J. J. Sebek, A. Terebilo SLAC, Menlo Park, California
	The SPEAR3 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 & improvement, fast orbit feedback, new chicane optics, low alpha optics & short bunches, low emittance optics, and new insertion devices. The accelerator physics group has a strong program to characterize and improve SPEAR3 performance.
FRPMS064	Electron Beam Lifeime in SPEAR3: Measurement and Simulation	4153
	W. J. Corbett X. Huang, M. J. Lee, P. Lui SLAC, Menlo Park, California B. Sayyar-Rodsari Pavilion Technologies, Inc, Austin, Texas
	Funding: Work supported by US Department of Energy Contract DE-AC03-76SF00515 and Office of Basic Energy Sciences, Division of Chemical Sciences. The primary contributing factors to electron beam lifetime in a storage ring are elastic and inelastic gas scattering, and intrabeam scattering. In order to further quantify the relative contributions of each mechanism, a series of measurements using vertical scraper position and rf-voltage sweeps were performed in SPEAR3 with fill patterns featuring different single-bunch and total beam currents. In parallel, an analytic beam-lifetime simulator was developed taking scattering cross-sections, rf-bucket height and bunch lengthening effects into account. In this paper, we compare measured results with the simulated results in an effort to develop a comprehensive model for electron beam lifetime under a variety of operating conditions.
FRPMS065	Bunch Length Measurements in SPEAR3	4159
	W. J. Corbett A. S. Fisher, X. Huang, J. A. Safranek, J. J. Sebek SLAC, Menlo Park, California A. H. Lumpkin ANL, Argonne, Illinois W. Y. Mok Life Imaging Technology, Palo Alto, California
	Funding: Work supported by US Department of Energy Contract DE-AC03-76SF00515 and Office of Basic Energy Sciences, Division of Chemical Sciences. In the nominal SPEAR3 storage ring optics, the natural radiation pulse length is 40ps fwhm per bunch. Due to the double-bend achromat lattice configuration, it is relatively straightforward to reduce the momentum compaction factor (α) and hence reduce the bunch length by modest values. In this paper we present streak camera measurements of the bunch length in the nominal optics, and with ~α/20 and α/50 optics as a function of single-bunch current. The results demonstrate <10ps fwhm radiation pulses with up 5x10⁸ particles/bunch (~100μ amp). Radiation pulse power, bunch length scaling and broadband impedance estimates are discussed.