diagnostics
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| MOPP034 | Upgrades of the Laser Beam-line at PITZ | laser, cathode, photo-cathode, emittance | 110 |
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Funding: This work has partly been supported by the European Community, contract numbers RII3-CT-2004-506008 and 011935, an by the "Impunls-und Vernetzungsfonds" of the Helmholtz Association, contract number VH-FZ-05 In spring of 2005 an essential upgrade of the photocathode laser and of the 27 m long laser beam-line took place at PITZ. A detectable improvement of the laser beam profile at the photocathode is expected. This improvement should lead to an additional reduction of the transverse emittance of the electron beam. The upgraded laser consists of a fully laser diode pumped scheme of pulse train oscillator, pre-amplifiers and booster amplifiers. The main advantages of this upgrade are improved stability, easier maintenance and long-term operations at 10 Hz repetition rate. In addition, the scheme of the optical beam-line was changed: The distance between the beam shaping aperture and the cathode was strongly reduced. Therefore a further improvement of the laser beam profile at the photocathode is expected. The laser beam-line is upgraded by an enlarged number of remotely controlled optical elements that allows the fine tuning of the laser beam characteristics during the running. New diagnostics tools are included in the laser beam-line. The paper focuses on the design of the new optical beam-line. It describes the results of electron beam measurements using the upgraded laser and the new PITZ2 electron beam-line in detail. |
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| MOPP053 | Incorporation of a PbSe Array Based Spectrograph into EPICS using LabView at the JLab FEL Facility | controls, fel, optics, spectrometer | 180 |
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Funding: This work supported by the Office of Naval Research, the Joint Technology Office, the Commonwealth of Virginia, the Air Force Research Laboratory, the Army Night Vision Lab, and by DOE Contract DE-AC05-84ER40150. A real-time spectrograph with a 1Hz update rate was designed and installed at the JLab FEL facility using a Cal Sensors PbSe array and a Roper Scientific SpectraPro 300 monochrometer. This paper describes the implementation of EPICS channel access on a remote PC running LabView with modification of vendor supplied LabView VI's to allow display of FEL light spectra in real-time on a remote workstation. This allows PC based diagnostics to be used in EPICS |
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| MOPP055 | The Infrared Undulator Project at the VUV-FEL | undulator, radiation, electron, resonance | 183 |
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Funding: University of Hamburg A special electromagnetic wiggler generating infrared radiation in the range 1-200 microns is planned to be installed at the DESY VUV-FEL in Hamburg by autumn 2006. The device is located after the FEL undulators, using the spent electron beam. The purpose is two-fold: first, it will serve longitudinal electron beam diagnostics, similar to other methods currently investigated using the coherent emission of radiation at wavelengths similar to the bunch length, and second it will be used as a powerful (100 MW peak) source for short (few ps) infrared radiation pulses. The natural, perfect synchronization with the VUV pulses will allow for pump-probe experiments with high timing precision. This paper will give an overview of the project, including the infrared beam transport line. |
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| THPP033 | Diagnostics Beamline for the SRF Gun Project | emittance, electron, gun, injector | 530 |
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Funding: Funded by the Bundesministerium für Bildung und Forschung, the State of Berlin and the Zukunftsfonds Berlin A superconducting rf photo electron injector (SRF gun) is currently under construction by a collaboration between BESSY, DESY, FZR and MBI. The project aims at the design and setup of an CW SRF gun including a diagnostics beamline for the ELBE FEL and to address R&D issues on low emittance injectors for future light sources such as the BESSY FEL. Of critical importance for the injector performance is the control of the electron beam parameters. For this reason a compact diagnostics beamline is under development serving a multitude of operation settings ranging from low-charge (77pC), low-emittance (1 pi mm mrad) mode to high-charge (2.5nC) operation of the gun. For these operation modes beam dynamics simulations are resulting in boundary conditions for the beam instrumentation. Proven and mature technology is projected wherever possible, for example for current and beam position monitoring. The layout of the beam profile and emittance measurement systems is described. For the bunch length, which varies between 5 and 50 ps, two schemes using Electro-optical sampling and Cherenkov radiation are detailed. The beam energy and energy spread is measured with an especially designed 180 degree spectrometer. |
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| THPP048 | Spatial Coherence Effects in the Transition Radiation Spectrum for Relativistic Charged Beams: Theoretical Results and Beam Diagnostics Implications | radiation, electron, photon, scattering | 576 |
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In the electromagnetic radiative phenomena originated by relativistic charged beams, angular distortions as well as variations of the photon flux are commonly observed as a function of the ratio between the beam transverse size and the observed wavelength, even at a wavelength shorter than the longitudinal bunch length. In the framework of a single particle theory of the transition radiation, diffractive alterations of the spectrum due, for instance, to the finite size of the radiator screen are already known. For relativistic three-dimensional charged beams, it could be interesting to check if the transition radiation emission undergoes modifications depending on the finite value of the beam transverse size with respect to the observed wavelength. Taking into account the beam diagnostics applications of the transition radiation in a linear accelerator, such an experimental check can offer promising perspectives. The theoretical background and physical basis of the spatial coherence effects affecting the spectral distribution of the transition radiation intensity in conditions of temporal incoherence will be presented. The main beam diagnostics applications will be also contoured. |
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