PAC2013 - List of Authors (Sun, Y.)

Paper	Title	Page
MOPHO07	A Seven-bend-achromat Lattice as a Potential Upgrade for the Advanced Photon Source	249
	M. Borland, V. Sajaev, Y. Sun ANL, Argonne, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357. The Advanced Photon Source (APS) is a 7-GeV storage ring light source that has been in operation since 1996. In that time, the emittance has dropped from 8 nm to 3 nm. The increasing feasibility of multi-bend-achromat lattices (e.g., the MAX-IV project) promises the possibility of a much greater reduction in emittance. In this paper, we show the design of a symmetric seven-bend-achromat lattice, including linear optics, nonlinear dynamics optimization, magnet requirements, and performance with errors.

MOPHO10	Optics Design and Beam Dynamics Optimization of a Five-bend Achromat Lattice for the Advanced Photon Source Upgrade	258
	Y. Sun, M. Borland ANL, Argonne, USA
	For the proposed APS upgrade, an ultimate storage ring (USR) with very low emittance has been studied. In this paper, one of the USRs’ lattice design is presented, which is composed of five-bend achromat cells. The linear and non-linear optics are optimized using the MOGA technique. Beam performance and collective effects are also preliminarily evaluated.

MOPHO11	Linear Scaling on Choosing a Bunch Compression Ratio for an FEL Driver	261
	Y. Sun ANL, Argonne, USA
	In this paper, a proper initial bunch length as a function of the main RF frequency and RF phase is estimated analytically by several approaches, assuming that no harmonic RF section is needed to linearize the energy modulation introduced during main RF acceleration. Next the upper limit of the bunch compression ratio in a single stage is evaluated analytically. The analytical relations derived on choosing a proper initial bunch length as a function of main RF frequency are confirmed by numerical simulation. These simple limit provide rough estimations and may be beneficial for choosing bunch compression ratios in different stages of an FEL driver, especially in a first stage bunch compression where there is usually a harmonic RF linearization applied.

MOPHO12	Simulation of an X-band Hard X-ray FEL with LCLS Injector	264
	Y. Sun ANL, Argonne, USA P. Emma LBNL, Berkeley, California, USA T.O. Raubenheimer SLAC, Menlo Park, California, USA
	In this note, it is briefly discussed the accelerator design and start-to-end 3D macro particles simulation (using {\small ELEGANT} and {\small GENESIS}) of an X-band RF driven hard X-ray FEL with LCLS injector. A preliminary design and LiTrack 1D simulation studies were presented before in an older publication~[chris]. In numerical simulations this X-band RF driven hard X-ray FEL achieves/exceeds LCLS-like performance in a much shorter overall length of 350 m, compared with 1200 m in the LCLS case. One key feature of this design is that it may achieve a higher final beam current of 5 kA plus a uniform energy profile, mainly due to the employment of stronger longitudinal wake fields in the last X-band RF linac~[tor].

MOPHO13	Achieving A Quasi Third Order Achromat in APS Upgrade Lattice	267
	Y. Sun, M. Borland ANL, Argonne, USA
	Next generation storage rings require stronger quadrupole focusing to achieve the very low emittance. Stronger sextupoles (usually at smaller dispersion locations) are then necessary to correct the natural chromaticity and head-tail instability. The geometric and chromatic optics abberations introduced by sextupoles have a large impact on the beam dynamics performance. In this paper, it is discussed how to achieve quasi third order achromat in the APS multi-bend achromat (MBA) lattices. Repetitive identical MBA arc cells with specified phase advance and mirror symmetry are employed. The beam dynamics performance of such a design is compared with a normal design.

MOPHO14	Analytical Evaluation of Correlated Timing Jitter Cancellation in a Staged Bunch Compression System	270
	Y. Sun ANL, Argonne, USA
	In this paper, the wake field cancellation scheme on the timing jitter is revisited. The correlated timing jitter effects between the photoinjector laser and linac RF phase are evaluated analytically. It is possible to minimize its impact on the final bunch length (peak current) variation by employing a longer linac with a lower acceleration gradient, between bunch compressor one and two.

MOPHO15	X-band FEL Driver Linac Design with Optics Linearization	273
	Y. Sun ANL, Argonne, USA P. Emma LBNL, Berkeley, California, USA T.O. Raubenheimer, J. Wu SLAC, Menlo Park, California, USA
	In this paper, a compact hard X-ray FEL design is proposed with a single bunch charge of 250 pC, which is based on all X-band RF acceleration and two stage bunch compression. It eliminates the need of a harmonic RF linearization section by employing optics linearization in its first stage bunch compression. Emittance growth in the horizontal plane due to CSR is investigated and minimized, to be on a similar level with the LCLS. An electron bunch distribution at the linac end is taken as the input for an FEL simulation in GENESIS, with a beam energy of 7 GeV. At an FEL radiation wavelength of 0.15 nm, a saturation length of roughly 40 meters can be achieved by employing an undulator with a period of 1.5 cm. Without tapering, an FEL radiation power above 10 GW is achieved with a photon pulse length of 50 fs, which is LCLS-like performance. The overall length of the accelerator plus undulator is around 250 meters which is much shorter than the LCLS length of 1230 meters.

Paper

Title

Page

A Seven-bend-achromat Lattice as a Potential Upgrade for the Advanced Photon Source

249

M. Borland, V. Sajaev, Y. Sun
ANL, Argonne, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357.
The Advanced Photon Source (APS) is a 7-GeV storage ring light source that has been in operation since 1996. In that time, the emittance has dropped from 8 nm to 3 nm. The increasing feasibility of multi-bend-achromat lattices (e.g., the MAX-IV project) promises the possibility of a much greater reduction in emittance. In this paper, we show the design of a symmetric seven-bend-achromat lattice, including linear optics, nonlinear dynamics optimization, magnet requirements, and performance with errors.

MOPHO10

Optics Design and Beam Dynamics Optimization of a Five-bend Achromat Lattice for the Advanced Photon Source Upgrade

258

Y. Sun, M. Borland
ANL, Argonne, USA

For the proposed APS upgrade, an ultimate storage ring (USR) with very low emittance has been studied. In this paper, one of the USRs’ lattice design is presented, which is composed of five-bend achromat cells. The linear and non-linear optics are optimized using the MOGA technique. Beam performance and collective effects are also preliminarily evaluated.

MOPHO11

Linear Scaling on Choosing a Bunch Compression Ratio for an FEL Driver

261

Y. Sun
ANL, Argonne, USA

In this paper, a proper initial bunch length as a function of the main RF frequency and RF phase is estimated analytically by several approaches, assuming that no harmonic RF section is needed to linearize the energy modulation introduced during main RF acceleration. Next the upper limit of the bunch compression ratio in a single stage is evaluated analytically. The analytical relations derived on choosing a proper initial bunch length as a function of main RF frequency are confirmed by numerical simulation. These simple limit provide rough estimations and may be beneficial for choosing bunch compression ratios in different stages of an FEL driver, especially in a first stage bunch compression where there is usually a harmonic RF linearization applied.

MOPHO12

Simulation of an X-band Hard X-ray FEL with LCLS Injector

264

Y. Sun
ANL, Argonne, USA
P. Emma
LBNL, Berkeley, California, USA
T.O. Raubenheimer
SLAC, Menlo Park, California, USA

In this note, it is briefly discussed the accelerator design and start-to-end 3D macro particles simulation (using {\small ELEGANT} and {\small GENESIS}) of an X-band RF driven hard X-ray FEL with LCLS injector. A preliminary design and LiTrack 1D simulation studies were presented before in an older publication~[chris]. In numerical simulations this X-band RF driven hard X-ray FEL achieves/exceeds LCLS-like performance in a much shorter overall length of 350 m, compared with 1200 m in the LCLS case. One key feature of this design is that it may achieve a higher final beam current of 5 kA plus a uniform energy profile, mainly due to the employment of stronger longitudinal wake fields in the last X-band RF linac~[tor].

MOPHO13

Achieving A Quasi Third Order Achromat in APS Upgrade Lattice

267

Y. Sun, M. Borland
ANL, Argonne, USA

Next generation storage rings require stronger quadrupole focusing to achieve the very low emittance. Stronger sextupoles (usually at smaller dispersion locations) are then necessary to correct the natural chromaticity and head-tail instability. The geometric and chromatic optics abberations introduced by sextupoles have a large impact on the beam dynamics performance. In this paper, it is discussed how to achieve quasi third order achromat in the APS multi-bend achromat (MBA) lattices. Repetitive identical MBA arc cells with specified phase advance and mirror symmetry are employed. The beam dynamics performance of such a design is compared with a normal design.

MOPHO14

Analytical Evaluation of Correlated Timing Jitter Cancellation in a Staged Bunch Compression System

270

Y. Sun
ANL, Argonne, USA

In this paper, the wake field cancellation scheme on the timing jitter is revisited. The correlated timing jitter effects between the photoinjector laser and linac RF phase are evaluated analytically. It is possible to minimize its impact on the final bunch length (peak current) variation by employing a longer linac with a lower acceleration gradient, between bunch compressor one and two.

MOPHO15

X-band FEL Driver Linac Design with Optics Linearization

273

Y. Sun
ANL, Argonne, USA
P. Emma
LBNL, Berkeley, California, USA
T.O. Raubenheimer, J. Wu
SLAC, Menlo Park, California, USA

In this paper, a compact hard X-ray FEL design is proposed with a single bunch charge of 250 pC, which is based on all X-band RF acceleration and two stage bunch compression. It eliminates the need of a harmonic RF linearization section by employing optics linearization in its first stage bunch compression. Emittance growth in the horizontal plane due to CSR is investigated and minimized, to be on a similar level with the LCLS. An electron bunch distribution at the linac end is taken as the input for an FEL simulation in GENESIS, with a beam energy of 7 GeV. At an FEL radiation wavelength of 0.15 nm, a saturation length of roughly 40 meters can be achieved by employing an undulator with a period of 1.5 cm. Without tapering, an FEL radiation power above 10 GW is achieved with a photon pulse length of 50 fs, which is LCLS-like performance. The overall length of the accelerator plus undulator is around 250 meters which is much shorter than the LCLS length of 1230 meters.