• J.A. Safranek, W.J. Corbett, X. Huang, J.J. Sebek
  SLAC, Menlo Park, California
• W.X. Cheng
  BNL, Upton, Long Island, New York

Funding: Work supported by the US Department of Energy, Office of Basic Energy Sciences.

In the past, SPEAR3 has had typically 50 to 70% injection efficiency. Much of the lost injected beam hit the small gap vacuum chambers at the insertion devices. We are now implementing injection with photon beamline shutters open, so these losses create Bremsstrahlung down the photon beamlines, increasing radiation levels on the photon experimental floor. In this paper, we describe work done to better control the booster to SPEAR (BTS) transport line beam so as to reduce losses during injection. We have used new BTS BPM electronics to control the transport line trajectory. The trajectory response on these BPMs has been used to correct the BTS optics. We use turn-by-turn BPM readings of the injected beam in SPEAR to optimize the BTS trajectory in all six transverse and longitudinal coordinates. We use turn-by-turn profile measurements of the injected beam to verify the BTS optics correction. The stainless steel windows have been removed from the BTS vacuum system to reduce the transverse dimensions of the injected beam.

• X. Huang, J.A. Safranek
  SLAC, Menlo Park, California

A preliminary plan for an infrared or terahertz beamline at SSRL is studied. Using chicane in a straight section allows us to redesign a section of the vacuum chamber and extract infrared/terahertz beam with a large acceptance. Under the low alpha operational mode, the terahertz beam power can be greatly enhanced by the coherent synchrotron radiation (CSR) effect. Calculations of photon beam flux and brightness and the shielding and CSR effects are presented.

• R.O. Hettel, K.L.F. Bane, K.J. Bertsche, Y. Cai, A. Chao, V.A. Dolgashev, J.D. Fox, X. Huang, Z. Huang, T. Mastorides, C.-K. Ng, Y. Nosochkov, A. Novokhatski, T. Rabedeau, C.H. Rivetta, J.A. Safranek, J. Seeman, J. Stohr, G.V. Stupakov, S.G. Tantawi, L. Wang, M.-H. Wang, U. Wienands, L. Xiao
  SLAC, Menlo Park, California
• I. Lindau
  Stanford University, Stanford, California
• C. Pellegrini
  UCLA, Los Angeles, California

Funding: This work was supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-76SF00515.

SSRL and SLAC groups are developing a long-range plan to transfer its evolving scientific programs from the SPEAR3 light source to a much higher performing photon source that would be housed in the 2.2-km PEP-II tunnel. While various concepts for the PEP-X light source are under consideration, including ultimate storage ring and ERL configurations, the present baseline design is a very low-emittance storage ring. A hybrid lattice has DBA or QBA cells in two of the six arcs that provide a total ~30 straight sections for ID beam lines extending into two new experimental halls. The remaining arcs contain TME cells. Using ~100 m of damping wigglers the horizontal emittance at 4.5 GeV would be ~0.1 nm-rad with >1 A stored beam. PEP-X will produce photon beams having brightnesses near 1022 at 10 keV. Studies indicate that a ~100-m undulator could have FEL gain and brightness enhancement at soft x-ray wavelengths with the stored beam. Crab cavities or other beam manipulation systems could be used to reduce bunch length or otherwise enhance photon emission properties. The present status of the PEP-X lattice and beam line designs are presented and other implementation options are discussed.

• J.A. Safranek, W.J. Corbett, X. Huang, J.J. Sebek, A. Terebilo
  SLAC, Menlo Park, California

Funding: Work supported by the US Department of Energy, Office of Basic Energy Sciences.

We present nonlinear dynamics measurements and tracking for the SPEAR3 storage ring. SPEAR3 does not have a vertical pinger magnet, so we have developed a method of measuring (x, y) frequency maps by exciting vertical oscillations using a strip line driven with a swept frequency. When the vertical oscillations reach the desired amplitude, the drive is cut, and an injection kicker excites horizontal oscillations. The subsequent free horizontal and vertical betatron oscillations are digitized turn-by-turn. We have used measured and tracked frequency maps in (x, y) and (x, energy) to characterize and optimize the dynamic aperture, injection and lifetime of the SPEAR3 low emittance optics.

• W.X. Cheng, W.J. Corbett, A.S. Fisher, X. Huang, J.A. Safranek, A. Terebilo
  SLAC, Menlo Park, California
• W.Y. Mok
  Life Imaging Technology, Palo Alto, California

Funding: Work sponsored by U.S. Department of Energy Contract DE-AC03-76SF00515 and Office of Basic Energy Sciences, Division of Chemical Sciences.

An intensified, fast-gated CCD camera was recently installed on the visible diagnostic beam line in SPEAR3. The ~2nS electronic gate capability, ability to make multiple-exposure images and to acquire sequences of images provides good diagnostic potential. Furthermore, the addition of a rotating mirror just upstream of the photocathode provides the ability to optically ‘streak’ multiple images across the photocathode. In this paper, we report on several fast-gated camera studies including (1) resonant excitation of vertical bunch motion, (2) imaging of the injected beam with and without emittance-spoiling windows in the upstream transfer line, (3) injection kicker tuning to minimize perturbations to the stored beam and (4) images of short-bunch ‘bursting’ in the low momentum-compaction mode of operation.