Katharina Witte

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The Photocathode Electron Gun (PEG) at SLAC is required to produce bunch intensities of up to 10 electrons within 2 ns (8 Amps). Operation of PEG has demonstrated a ‘Charge Limit’ phenomenon, whereby the charge that can be extracted from the gun with an intense laser beam saturates at significantly less than 10 electrons (the expected ‘Space Charge Limited’(More)
The Stanford Linear Accelerator has been running with polarized electrons both in the collider (SLC) mode and in the fixed target mode. The accelerator's polarized electron source is based on a thin, strained GaAs photocathode, which is held at a negative high voltage and illuminated by a Titanium Sapphire laser. The reliability of the source was better(More)
The SLAC Gun Test Laboratory apparatus, the first two meters of which is a replica of the SLAC injector, is used to study the production of intense, highly–polarized electron beams required for the Stanford Linear Collider and future linear colliders. The facility has been upgraded with a Mott polarimeter in order to characterize the electron polarization(More)
Grazing incidence and grazing emission X-ray fluorescence spectroscopy (GI/GE-XRF) are techniques that enable nondestructive, quantitative analysis of elemental depth profiles with a resolution in the nanometer regime. A laboratory setup for soft X-ray GEXRF measurements is presented. Reasonable measurement times could be achieved by combining a highly(More)
In this work, a novel laser-produced plasma source is presented which delivers pulsed broadband soft X-radiation in the range between 100 and 1200 eV. The source was designed in view of long operating hours, high stability, and cost effectiveness. It relies on a rotating and translating metal target and achieves high stability through an on-line monitoring(More)
The interaction of the central magnesium atom of chlorophyll a (Chl a) with the carbon and nitrogen backbone was investigated by magnesium K near-edge X-ray absorption fine structure (NEXAFS) spectroscopy in fluorescence detection mode. A crude extract of Chl a was measured as a 1 × 10(-2) mol/L ethanol solution (which represents an upper limit of(More)
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