DESY, Hamburg
PETRA III is a new hard x-ray synchrotron radiation source which will be operated at 6 GeV with an extremely low horizontal emittance of 1 nmrad. This new facility is the result of a conversion of the existing storage ring PETRA II into a light source. The conversion comprises the complete rebuilding of one eighth of the 2304 m long storage ring, which will then house 14 undulator beam lines, the optical and experimental hutches, and the modernization and refurbishment of the remaining seven eighths. In addition two 100 m long damping wiggler sections have been installed which are required to achieve the small design emittance. Construction, installation and technical commissioning have been finished middle of March and then the commissioning with beam started. In this paper we present the results that have been achieved during commissioning with special emphasis on the role of diagnostic systems.
PSI, Villigen
ELETTRA, Basovizza
CERN, Geneva
Currently a X band traveling wave accelerator structure is fabricated in a collaboration between CERN and PSI. It will compensate nonlinearities in the longitudinal phase space at the injector prototype of the PSI-XFEL, whereas CERN will use it to test break down limits and rates in the high gradient regime. Due to the modest beam energies, the operation in the PSI-XFEL injector is quite sensitive to transverse wakes destroying the beam emittance. In that respect, the structure will use an active monitoring of the beam to structure alignment and include two wake field monitors coupling to the transverse higher order modes. These allow steering the beam to the structure axis giving a higher precision than mechanical alignment strategies. Localized offsets due to bends or tilts have individual signatures in the frequency spectrum, which in turn are correlated with different delays in the signal envelope. By taking advantage of this combined with the single bunch mode at the PSI-XFEL, the use of a relatively simple detector type RF front end should be possible, which will not only show beam offsets, but also higher order misalignments as tilts in the structure.
DESY, Hamburg
The Positron Intensity Accumulator PIA at DESY is used to accumulate the intensity and damp down the emittance of the positrons produced in the Linac II before they are injected into DESY II. Up to 19 shots are collected and damped. During the damping process the (baseband) peak current is increased by about a factor 4. Therefore the signal from the circulating beam can be up to 80 times bigger than the injected beam and hence overload any first turn detectors. The injected beam however is bunched by the 3 GHz RF of the linac. By filtering the 3 GHz component of the antenna signal and subsequent demodulation it is possible to set up a BPM system detecting exclusively the injected beam.
CELLS-ALBA Synchrotron, Cerdanyola del Vallès
The design of the stripline kickers shall be adapted to match the line impedance, maximize the effective beam kick, reduce the heat load and minimize the transverse coupling impedance. These kickers are used for either tune measurements or transverse feedback. We describe the ALBA design of these kickers for both Booster and Storage Ring.
Fermilab, Batavia
KEK, Ibaraki
To achieve a low vertical beam emittance at the KEK Accelerator Test Facility (ATF) damping ring, the BPM read-out system is currently upgraded with new high resolution electronics. Based on analog and digital down-conversion techniques, the upgrade includes an automatic gain calibration system to correct for slow drift effects and ensure high reproducable beam position readings. The concept and its technical realization, as well as preliminary beam study results are presented.
DESY, Hamburg
The basic design for the machine protection system (MPS) for the light-source PETRA III is discussed. High synchrotron radiation can damage absorbers and vacuum chambers. Therefore the MPS identifies alarm conditions from different systems, including the BPM, temperature and vacuum systems and creates a dump command within 100us. For diagnostic purposes a post-mortem trigger is implemented and a first alarm detection is planned. The initial commissioning of the MPS with its alarm-delivering systems is described.