• K. Sakaue, A. Endo, M. Washio
  RISE, Tokyo

We will present a design of high brightness light source for EUV lithography mask inspection. The required system parameters are minimum brightness of 2500W/mm2/Sr at 13.5nm/2% bandwidth. Our design consists of super-conducting DC RF-gun as a radiator and 10.74nm CO₂ laser stacked in an optical cavity as a laser undulator. Recent achievements of each component technologies, which is 1.3GHz SC-RF-gun, 10kW average power short pulse CO₂ laser, and laser storage optical super-cavity, indicate the feasibility of producing required brightness based on laser Compton undulator. Design parameters of high brightness EUV source, the technological gap of the present component technologies and required further developments will be resented at the conference.

• D. Filippetto, M. Bellaveglia, E. Chiadroni, A. Gallo, B. Marchetti
  INFN/LNF, Frascati (Roma)
• A. Cianchi
  INFN-Roma II, Roma
• A. Mostacci
  Rome University La Sapienza, Roma
• C. Ronsivalle
  ENEA C.R. Frascati, Frascati (Roma)

Ultra-short electron bunch production is attractive for a large number of applications ranging from short wavelength free electron lasers (FEL), THz radiation production, linear colliders and plasma wake field accelerators. SPARC is a test facility able to accelerate high brightness beam from RF guns up to 150 MeV allowing a wide range of beam physics experiments. Those experiments require detailed beam measurements and careful data analysis. In this paper we discuss the techniques currently used in our machine; by combining quadrupoles, RF deflector, spectrometer dipole and reliable data analysis codes, we manage to characterize the 6D phase space and the beam slice properties. We focus on the ongoing studies on the emittance compensation in the velocity bunching regime.

• H. Kashiwagi, I. Ishibori, T. Ishizaka, S. Kurashima, N. Miyawaki, T. Nara, S. Okumura, W. Yokota, K. Yoshida, Y. Yuri, T. Yuyama
  JAEA/TARRI, Gunma-ken

It is important to match the injection beam emittance to the acceptance of an accelerator for high beam transmission A system to evaluate transverse beam matching has been developed in the JAEA AVF cyclotron facility. In this presentation, concepts of an apparatus for transverse acceptance measurement will be reported. The apparatus consists of a phase-space collimator in the injection beam line and beam current monitor after the cyclotron. The collimator consists of two pairs of position defining slits and angle defining slits to inject an arbitrarily small portion of transverse phase-space into the cyclotron. Measurement of the acceptance is made by testing every portion in the whole phase-space, which should large enough to cover the acceptance. The acceptance can be estimated from the sum of the portions of the beam which passes through the system.

• Q. Luo, J. Fang, D.H. He, B. Sun
  USTC/NSRL, Hefei, Anhui

An s-band re-entrant cavity BPM system is designed for new high brightness injector at HLS. A prototype cavity BPM system was manufactured for off-line test, which is also called cold test. According to the results of computer simulation, wire scanning off-line test method can be used to calibrate the BPM and estimate the performance of the on-line BPM system. Cross-talk problem was detected during the cold test. Ignoring nonlinear effect, transformation matrix is a way to correct cross-talk. Analysis of cold test results showed that position resolution of prototype BPM is better than 3 μm.

• G. Pöplau, U. van Rienen
  Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock

Precise and fast 3D space-charge calculations for bunches of charged particles are still of growing importance in recent accelerator designs. Whereas an adaptive discretization of a bunch is often required for efficient space charge calculations in practice, such a technique is not implemented in many computer codes. For instance, the FFT Poisson solver that is often applied allows only an equidistant mesh. An adaptive discretization following the particle density distribution is implemented in the GPT tracking code (General Particle Tracer, Pulsar Physics) together with a multigrid Poisson solver. The disadvantage of this approach is that jumps in the distribution of particles are not taken into account and the hierarchical construction of meshes in multigrid can not be used. In this paper we present an approach to an adaptive discretization which is based on the multigrid technique. The goal is that the error estimator needed for the adaptive distribution of mesh lines can be calculated directly from the multigrid procedure. The algorithm will be investigated for several particle distributions and compared to that adaptive discretization method implemented in GPT.

• F.V. Hartemann, F. Albert, S.G. Anderson, C.P.J. Barty, A.J. Bayramian, T.S. Chu, R.R. Cross, C.A. Ebbers, D.J. Gibson, R.A. Marsh, D.P. McNabb, M. J. Messerly, M. Shverdin, C. Siders
  LLNL, Livermore, California
• E.N. Jongewaard, T.O. Raubenheimer, S.G. Tantawi, A.E. Vlieks
  SLAC, Menlo Park, California
• V. A. Semenov
  UCB, Berkeley, California

Recent progress in accelerator physics and laser technology have enabled the development of a new class of tunable gamma-ray light sources based on Compton scattering between a high-brightness, relativistic electron beam and a high intensity laser pulse produced via chirped-pulse amplification (CPA). A precision, tunable Mono-Energetic Gamma-ray (MEGa-ray) source driven by a compact, high-gradient X-band linac is currently under development and construction at LLNL. High-brightness, relativistic electron bunches produced by an X-band linac designed in collaboration with SLAC will interact with a Joule-class, 10 ps, diode-pumped CPA laser pulse to generate tunable γ-rays in the 0.5-2.5 MeV photon energy range via Compton scattering. This MEGa-ray source will be used to excite nuclear resonance fluorescence in various isotopes. Applications include homeland security, stockpile science and surveillance, nuclear fuel assay, and waste imaging and assay. The source design, key parameters, and current status are presented, along with important applications, including nuclear resonance fluorescence, photo-fission, and medical imaging.

• T. Nakamura
  JASRI/SPring-8, Hyogo-ken

Multiturn circulation of a beam from an energy recovery linac (ERL) in a light source with bunch-by-bunch switching devices with RF cavities can reduce the output current of the ERL by a factor of the number of turns of the circulation, keeping the average current of the light source*. This scheme eases the requirement of an electron gun and an ERL, and lead to the possibility of cost-effective multi-pass ERL scheme. In previous work*, the scheme to increase the number of circulation with a ring shaped beam transport was proposed. In this work we propose a scheme without ring-shaped transport and it can be applied to various shapes of ERLs and light sources. As an example, we show a nine-turn circulation light source with the combination of newly proposed three-turn circulation system. The detail of the system, the brightness including the growth of emittance and energy spread by radiation excitation, and the effect of round-to-flat beam conversion which is a possible method for the reduction of the growth of the horizontal emittance are discussed.

* T. Nakamura, Phys. Rev. ST Accel. Beams 11, 032803 (2008).

• J.N. Corlett, K.M. Baptiste, J.M. Byrd, P. Denes, R.W. Falcone, J. Feng, J. Kirz, D. Li, H.A. Padmore, C. F. Papadopoulos, G. Penn, J. Qiang, D. Robin, R.D. Ryne, F. Sannibale, R.W. Schoenlein, J.W. Staples, C. Steier, T. Vecchione, M. Venturini, W. Wan, R.P. Wells, R.B. Wilcox, J.S. Wurtele, A. Zholents
  LBNL, Berkeley, California
• A.E. Charman, E. Kur
  UCB, Berkeley, California

Recent reports have identified the scientific requirements for a future soft x-ray light source and a high-repetition-rate FEL facility responsive to them is being studied at LBNL. The facility is based on a CW superconducting linear accelerator with beam supplied by a high-brightness, high-repetition-rate photocathode electron gun, and on an array of FELs to which the beam is distributed, each operating at high repetition rate and with even pulse spacing. Dependent on the experimental requirements, the individual FELs may be configured for either SASE, HGHG, EEHG, or oscillator mode of operation, and will produce high peak and average brightness x-rays with a flexible pulse format ranging from sub-femtoseconds to hundreds of femtoseconds. We are developing a design concept for a 10‐beamline, coherent, soft x‐ray FEL array powered by a 2.5 GeV superconducting accelerator operating with a 1 MHz bunch repetition rate. Electron bunches are fanned out through a spreader, distributing beams to an array of 10 independently configurable FEL beamlines with nominal bunch rates up to 100 kHz. Additionally, one beamline could be configured to operate at higher repetition rate.

• C. Steier, B.J. Bailey, A. Biocca, A. Madur, H. Nishimura, G.J. Portmann, S. Prestemon, D. Robin, S.L. Rossi, F. Sannibale, T. Scarvie, D. Schlueter, W. Wan, L. Yang
  LBNL, Berkeley, California

The Advanced Light Source is one of the earliest 3rd generation light sources. With an active upgrade program it has remained competitive over the years. The latest in a series of upgrades is a lattice upgrade project that was started in 2009. When it will be completed, the ALS will operate with a horizontal emittance of 2.2 nm and an effective emittance of 2.6 nm. Combined with the high current of 500 mA and the small vertical emittance the ALS already operates at this upgrade will keep it competitive for years to come. The presentation will present the status of the upgrade, including beam dynamics studies and lattice optimizations as well as the magnet design and status.

• Y. Cai, K.L.F. Bane, K.J. Bertsche, A. Chao, R.O. Hettel, X. Huang, Z. Huang, C.-K. Ng, Y. Nosochkov, A. Novokhatski, T. Rabedeau, J.A. Safranek, G.V. Stupakov, L. Wang, M.-H. Wang, L. Xiao
  SLAC, Menlo Park, California

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 PEP-II tunnel. The design features a hybrid lattice with double bend achromat cells in two arcs and theoretical minimum emittance cells in the remaining four arcs. Damping wigglers 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 intra-beam 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 10²² (ph/s/mm²/mrad²/0.1% 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 paper, we will present the study of the lattice properties, nonlinear dynamics, intra-beam scattering and Touschek lifetime, and collective instabilities. Finally, we discuss the possibility of partial lasing at soft X-ray wavelengths using a long undulator in a straight section.

• G. Rakowsky
  BNL, Upton, Long Island, New York

Various magnet sorting strategies have been used to minimize trajectory and phase errors in undulators, ranging from intuitive pairing of stronger and weaker magnets, to full 3D FEM simulation with actual Helmholtz coil magnet data. We present a simpler approach, first deriving trajectory displacement, kick angle and phase error signatures of each component of magnetization error from a 3D Radia* undulator model. Then, for a given sequence of magnets, the trajectory and phase profiles are computed by cumulatively summing the scaled displacements and phase errors. The rms error is then minimized by swapping magnets according to one's favorite optimization method. A fast, simple magnet swapping algorithm, implemented in Mathematica, is described. 100,000 iterations take only minutes, so dozens of solutions can be compared. This approach was applied recently at NSLS to a short in-vacuum undulator, which required no trajectory or phase shimming. We also obtain trajectory and phase error signatures of some mechanical errors, to guide "virtual shimming" and specifying mechanical tolerances. Finally, multipole signatures of some simple inhomogeneities are modeled.

* O. Chubar, P. Elleaume, J. Chavanne, "A 3D Magnetostatics Computer Code for Insertion Devices", SRI97 Conference August 1997, J. Synchrotron Rad. (1998). 5, 481-484

• J.B. Rosenzweig, G. Andonian, A. Fukasawa, E. Hemsing, G. Marcus, A. Marinelli, P. Musumeci, B.D. O'Shea, F.H. O'Shea, C. Pellegrini, D. Schiller, G. Travish
  UCLA, Los Angeles, California
• P.H. Bucksbaum, M.J. Hogan, P. Krejcik
  SLAC, Menlo Park, California
• M. Ferrario
  INFN/LNF, Frascati (Roma)
• S.J. Full
  Penn State University, University Park, Pennsylvania
• P. Muggli
  USC, Los Angeles, California

Recent initiatives at UCLA concerning ultra-short, GeV electron beam generation have been aimed at achieving sub-fs pulses capable of driving X-ray free-electron lasers (FELs) in single-spike mode. This uses of very low charge beams, which may allow existing FEL injectors to produce few-100 attosecond pulses, with very high brightness. Towards this end, recent experiments at the Stanford X-ray FEL (LCLS, first of its kind, built with essential UCLA leadership) have produced ~2 fs, 20 pC electron pulses. We discuss here extensions of this work, in which we seek to exploit the beam brightness in FELs, in tandem with new developments at UCLA in cryogenic undulator technology, to create compact accelerator/undulator systems that can lase below 0.15 Angstroms, or be used to permit 1.5 Angstrom operation at 4.5 GeV. In addition, we are now developing experiments which use the present LCLS fs pulses to excite plasma wakefields exceeding 1 TV/m, permitting a table-top TeV accelerator for frontier high energy physics applications.