| Paper |
Title |
Page |
| TUPP023 |
Direct Detection of the Electron Cloud at ANKA
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1580 |
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- S. Casalbuoni, A. W. Grau, M. Hagelstein, A.-S. Müller
FZK, Karlsruhe
- U. Iriso
ALBA, Bellaterra
- E. M. Mashkina
University of Erlangen-Nürnberg, Physikalisches Institut II, Erlangen
- R. Weigel
Max-Planck Institute for Metal Research, Stuttgart
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Low energy electrons generated by the interaction of high energy particles with the beam pipe surface can be detrimental for accelerators performances increasing the vacuum pressure, the heat load and eventually producing beam instabilities. The low energy electrons accumulating in the beam pipe are often referred to as electron cloud. In this presentation we report on the direct evidence of the electron cloud in the electron storage ring of the synchrotron light source ANKA (ANgstrom source KArlsruhe).
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| WEPC046 |
Characterizing THz Coherent Synchrotron Radiation at the ANKA Storage Ring
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2091 |
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- A.-S. Müller, I. Birkel, S. Casalbuoni, B. Gasharova, E. Huttel, Y.-L. Mathis, D. A. Moss, N. J. Smale, P. Wesolowski
FZK, Karlsruhe
- E. Bruendermann
Ruhr-Universität Bochum, Bochum
- T. Bueckle, M. Klein
University of Karlsruhe, Karlsruhe
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In a synchrotron radiation source coherent infrared (IR) radiation is emitted when the bunch length is comparable to the wavelength of the emitted radiation. To generate coherent THz (far IR) radiation, the ANKA storage ring is operated regularly in a dedicated low-alpha optics. Different bunch lengths, corresponding to different spectral ranges of the THz spectrum and various electron beam energies can be offered, depending on user demand. The radiation emitted in the fringe field of a dipole magnet, the so-called edge radiation, is detected at the ANKA-IR beamline. This paper presents radiation properties like THz beam profiles and power measurements in the framework of characterising the coherent THz radiation to optimise the power, frequency and spatial output of the ANKA storage ring. First experiments showed a time averaged power of up to 0.2 mW suggesting a THz pulse peak power of at least several tens of mW.
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| WEPC047 |
Modeling the Shape of Coherent THz Pulses Emitted by Short Bunches in an Electron Storage Ring
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2094 |
| |
- A.-S. Müller, S. Casalbuoni, M. Fitterer, E. Huttel, Y.-L. Mathis
FZK, Karlsruhe
- M. T. Schmelling
MPI-K, Heidelberg
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A sufficiently short electron bunch will emit coherent synchrotron radiation of wavelengths equal to or larger than the bunch length. The shape of the emitted THz pulse depends amongst other things on the original shape and length of the bunch’s charge distribution. A Michelson interferogram of the THz signal therefore contains information on the generating bunch. However, systematic effects make a bunch length measurement based on that technique non-trivial. In order to understand the variables involved, an analytical model of the pulse generation is needed. In this paper, a derivation of the THz pulse shape form first principles with special emphasis in the time domain is presented. The impact of charge distribution parameters on the Michelson interferogram is discussed.
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| WEPC103 |
Design of a Cold Vacuum Chamber for Diagnostics
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2240 |
| |
- S. Casalbuoni, T. Baumbach, A. W. Grau, M. Hagelstein, R. Rossmanith
FZK, Karlsruhe
- V. Baglin, B. Jenninger
CERN, Geneva
- R. Cimino
INFN/LNF, Frascati (Roma)
- M. P. Cox
Diamond, Oxfordshire
- E. M. Mashkina
University of Erlangen-Nürnberg, Physikalisches Institut II, Erlangen
- E. J. Wallén
MAX-lab, Lund
- R. Weigel
Max-Planck Institute for Metal Research, Stuttgart
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Preliminary studies performed with the cold bore superconducting undulator installed in the ANKA storage ring suggest that the beam heat load is mainly due to the electron wall bombardment. Low energy electrons (few eV) are accelerated by the electric field of the beam to the wall of the vacuum chamber, induce non-thermal outgassing from the cryogenic surface and heat the undulator. In this contribution we report on the design of a cold vacuum chamber for diagnostics to be installed in the ANKA (ANgstrom source KArlsruhe) storage ring and possibly in third generation light sources. The diagnostics implemented are: - retarding field analyzers to measure the electron energy and flux,
- temperature sensors to measure the total heat load,
- pressure gauges,
- and a mass spectrometer to measure the gas content.
The aim of this device is to gain a deeper understanding on the heat load mechanisms to a cold vacuum chamber in a storage ring and find effective remedies. The outcome of the study is of relevance for the design and operation of cold bore superconducting insertion devices in synchrotron light sources.
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| WEPC121 |
Magnetic Measurement Device for Superconductive Undulator Mock-up Coils at ANKA
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2291 |
| |
- E. M. Mashkina, B. K. Kostka, E. Steffens
University of Erlangen-Nürnberg, Physikalisches Institut II, Erlangen
- T. Baumbach, A. Bernhard, D. Wollmann
University of Karlsruhe, Karlsruhe
- S. Casalbuoni, A. W. Grau, M. Hagelstein, R. Rossmanith
FZK, Karlsruhe
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A device for precise magnetic measurements of superconductive coils was designed, built and installed at the synchrotron radiation source ANKA, Forschungszentrum Karlsruhe. Accurate magnetic field measurements are a prerequisite for the characterization and optimization of insertion devices. The new device allows measuring the magnetic field magnitude of test coils with a longitudinal precision of 10 μm using a 2D Hall probe bench. The cylindrical liquid He cryostat allows mounting coils of maximum dimensions 50 cm in length and 30 cm in diameter. The set-up is computer controlled. The contribution will present the new device as well as the results obtained.
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| WEPC125 |
Development of Three New Superconducting Insertion Devices for the ANKA Storage Ring
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2300 |
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- R. Rossmanith, S. Casalbuoni, A. W. Grau, M. Hagelstein
FZK, Karlsruhe
- T. Baumbach, A. Bernhard, P. Peiffer, D. Wollmann
University of Karlsruhe, Karlsruhe
- C. Boffo, M. Borlein, W. Walter
BNG, Würzburg
- B. K. Kostka, E. M. Mashkina, E. Steffens
University of Erlangen-Nürnberg, Physikalisches Institut II, Erlangen
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After a first successful test of a superconductive cold bore undulator in ANKA a new generation of superconductive insertion devices is under construction or in a detailed planning phase. The first one, referred to as as SCU14 and now under construction, is an improved version of the existing undulator (14 mm period length, 100 periods long) with a new cooling scheme for small gap operation and a reduced field error. The period length of the second device called SCUW can be switched electrically between 15 and 45 mm. The third one is a superconductive undulator which can tolerate a beam heat load of several Watts in combination with a small field error named SCU2. It is designed for third generation light sources with a heat load of up to 6 Watt from the beam to the cold bore.
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