Jimmy L Turner

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The beam diagnostics in the linac for the Linac Coherent Light Source (LCLS) X-ray FEL project at SLAC includes optical transition radiation (OTR) screens for measurements of transverse and longitudinal beam properties. We report on observations of coherent light emission from the OTR screens (COTR) at visible wavelengths from the uncompressed and(More)
A scheme for generating two simultaneous hard-x-ray free-electron laser pulses with a controllable difference in photon energy is described and then demonstrated using the self-seeding setup at the Linac Coherent Light Source (LCLS). The scheme takes advantage of the existing LCLS equipment, which allows two independent rotations of the self-seeding diamond(More)
The Linac Coherent Light Source (LCLS) is a SASE xray Free-Electron Laser (FEL) project presently under construction at SLAC [1]. The injector section, from drive laser and RF photocathode gun through first bunch compressor chicane, was installed in fall 2006. Initial system commissioning with an electron beam was completed in August 2007, with the goal of(More)
The luminosity of the SLAC Linear Collider (SLC) has been increased by more than a factor of three during the 1997-98 run. Improved alignment and emittance tuning techniques throughout the accelerator resulted in minimal emittance growth from the damping rings to the final focus. In particular, a revised strategy for wakefield cancellation using precision(More)
Vibration measurements of the linear accelerator structures in the SLC linac show a 1 micron rms vertical motion. This motion reduces to 0.2 micron rms motion when the cooling water to the accelerator structures is turned off. The quadrupoles have 250 nanometer rms vertical motion with the accelerator structure cooling water on and 60 nanometer motion with(More)
We present experimental studies of the gain length and saturation power level from 1.5 nm to 1.5 Å at the Linac Coherent Light Source (LCLS). By disrupting the FEL process with an orbit kick, we are able to measure the X-ray intensity as a function of undulator length. This kick method is cross-checked with the method of removing undulator sections. We also(More)
To assess the functional capability of human milk lymphocytes, we studied phytohemagglutinin-induced lymphokine production by breast milk and, for comparison, peripheral blood lymphocyte cultures. Two lymphokines, lymphocyte-derived chemotactic factor (LDCF) and immune interferon, were assayed in supernatants of milk and blood lymphocyte cultures obtained(More)
There is growing concern that the use of antimicrobials in livestock feeding to enhance growth and to prevent disease is leading to increasing numbers of antibiotic-resistant human and animal pathogens. The exact degree of antibioticresistant organisms attributed to the use of antimicrobial agents in livestock feeding remains to be proven. Despite the lack(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)