Alan S. Fisher

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The recently commissioned Linac Coherent Light Source is an X-ray free-electron laser at the SLAC National Accelerator Laboratory. It produces coherent soft and hard X-rays with peak brightness nearly ten orders of magnitude beyond conventional synchrotron sources and a range of pulse durations from 500 to <10 fs (10 s). With these beam characteristics this(More)
PEP-II is a 2.2 km-circumference collider with a 2.1 A, 3.1 GeV positron ring (the low-energy ring) 1 m above a 1 A, 9 GeV electron ring (the high-energy ring); both rings are designed to allow an upgrade to 3 A. Since June 1997, we have had three runs totaling 14 weeks to commission the full HER, reaching a current of 0.75 A. Positrons were transported(More)
Measuring the beam parameters at the interaction point (IP) of ee colliders has historically been both essential and extremely challenging for accelerator builders. Exploiting the shape of the event-vertex distribution to measure bunch length, emittance and IP β-function was pioneered by Cinabro et al. [1][2] using the CLEO detector at CESR; a similar(More)
Plasma accelerators driven by ultra-relativistic electron beams have demonstrated greater than 50 GeV/m acceleration gradients over a distance of a meter [1] though the accelerated particles typically have had a 100% energy spread when a single drive bunch was used. However, it is known that by locally producing electrons via ionization within the(More)
SLAC has two electron accelerators, the Linac Coherent Light Source (LCLS) and the Facility for Advanced Accelerator Experimental Tests (FACET), providing high-charge, high-peak-current, femtosecond electron bunches. These characteristics are ideal for generating intense broadband terahertz (THz) pulses via coherent transition radiation. For LCLS and FACET(More)
Pre-concentration of analytes, or matrix removal to overcome interferences using mini- or micro-columns of exchange media prior to atomic spectrometric detection is becoming increasingly more common. This paper is a review of some of the more recent applications of chelating, ion exchange and other resins and gels that have been used to accomplish this.
High-efficiency acceleration of charged particle beams at high gradients of energy gain per unit length is necessary to achieve an affordable and compact high-energy collider. The plasma wakefield accelerator is one concept being developed for this purpose. In plasma wakefield acceleration, a charge-density wake with high accelerating fields is driven by(More)
PEP-II [1-9] is an e+ecollider with asymmetric energies (3.1 and 9 GeV, respectively) in a 2200 m tunnel at the Stanford Linear Accelerator Center. The collider produces B mesons to study a particle physics effect called CP violation as well as other physics topics. PEP-II was completed in 1998 with the first luminosity generated in July of that year. The(More)