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[en] A bunch-by-bunch feedback system has been developed to suppress longitudinal coupled-bunch instabilities at the KEK-PF. A longitudinal kicker based on a DAFNE-type overdamped cavity has been designed and installed in the ring, and a general purpose signal processor, called iGp, has been developed by the collaboration of the KEK, SLAC, and INFN-LNF. The entire feedback loop has been closed by the end of June 2007, and the feedback system has successfully suppressed the longitudinal dipole-mode instabilities up to 430 mA.
[en] The Stanford Linear Accelerator Center (SLAC) uses a maintenance management philosophy that is best described as opportunistic or event-driven. Opportunistic maintenance can be defined as a systematic method of collecting, investigating, pre-planning, and publishing a set of proposed maintenance tasks and acting on them when there is an unscheduled failure or repair ''opportunity''. Opportunistic maintenance can be thought of as a modification of the run-to-fail maintenance management philosophy. This maintenance plan was adopted and developed to improve the overall availability of SLAC's linear accelerator, beam delivery systems, and associated controls, power systems, and utilities. In the late 1980's, as the technical complexity of the accelerator facility increased, variations on a conventional maintenance plan were used with mixed results. These variations typically included some type of regular periodic interruption to operations. The periodic shutdowns and unscheduled failures were additive and resulted in unsatisfactory availability. Maintenance issues are evaluated in a daily meeting that includes the accelerator managers, maintenance supervisors and managers, safety office personnel, program managers, and accelerator operators. Lists of pending maintenance tasks are made available to the general SLAC population by a World Wide Web site on a local internet. A conventional information system which pre-dates the WWW site is still being used to provide paper copies to groups that are not yet integrated into the WWW system. The local internet provides real time maintenance information, allowing people throughout the facility to track progress on tasks with essentially real-time status updates. With the introduction of opportunistic maintenance, the accelerator's availability has been measurably better. This paper will discuss processes, rolls and responsibilities of key maintenance groups, and management tools developed to support opportunistic maintenance
[en] The two mile long Main Drive Line (MDL) distributes 476MHz at each of the 31 sectors along its length. Each of the 31 sectors has a six times multiplier which drives the 2856MHz phase reference system for that sector. This system is used to set and maintain phase of the accelerator structures over time. During previous runs significant down time resulted from sector phasing which was required after multiplier replacement. A system was designed to calibrate the phase of the 476MHz input to the phase of the 2856MHz output of the multiplier units. This enabled multipliers to be replaced without rephasing sectors.
[en] SESAME is a rather unique effort to nurture both high quality research and scientific collaboration in the Middle East. Eliezer Rabinovici of the Racah Institute of Physics will present a personal perspective on how the project came about, where it is now and where it may be heading for.
[en] Alternative chicane-type beam lines are proposed for exact emittance exchange between horizontal phase space (x; x(prime)) and longitudinal phase space (z; (delta)). Methods to achieve exact phase space exchanges, i.e. mapping x to z, x(prime) to (delta), z to x and (delta) to x(prime) are suggested. Methods to mitigate the thick-lens effect of the transverse cavity on emittance exchange are discussed. Some applications of the phase space exchanger and the feasibility of an emittance exchange experiment with the proposed chicane-type beam line at SLAC are discussed.
[en] The SLAC Damped Detuned Structure (DDS) is an accelerator structure designed to suppress the long range transverse wakefields which limit the performance of high current multibunch accelerators. We discuss the conceptual considerations which have led to its development and discuss the steps involved in arriving at a design
[en] Increasing the peak rf power available from X-band microwave tubes by means of rf pulse compression is envisioned as a way of achieving the few-hundred-megawatt power levels needed to drive a next-generation linear collider with 50-100 MW klystrons. SLED-II is a method of pulse compression similar in principal to the SLED method currently in use on the SLC and the LEP injector linac. It utilizes low-loss resonant delay lines in place of the storage cavities of the latter. This produces the added benefit of a flat-topped output pulse. At SLAC, the authors have designed and constructed a prototype SLED-II pulse-compression system which operates in the circulator TE01 mode. It includes a circular-guide 3-dB coupler and other novel components. Low-power and initial high-power tests have been made, yielding a peak power multiplication of 4.8 at an efficiency of 40%. The system will be used in providing power for structure tests in the ASTA (Accelerator Structures Test Area) bunker. An upgraded second prototype will have improved efficiency and will serve as a model for the pulse compression system of the NLCTA (Next Linear Collider Test Accelerator)
[en] The year 2005 was named the World Year of Physics in recognition of the 100th anniversary of Albert Einstein's legacy in the field of physics. The video covers many of Einstein's long-standing achievements, particularly those related to the landmark papers of 1905.
[en] Everyone knows that lasers can be bright. From Goldfinger to Star Wars, intense lasers carry a 'death ray' reputation in popular culture. But what is intense light, anyway? How can you even make or direct something that will blast to smithereens any material that it encounters? And how can something as ephemeral as a ray of light turn into an irresistible force? Is there an ultimate intensity, a brightest light? We'll answer these questions, and more.