| Paper |
Title |
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| TUPCH032 |
Precise Measurements of the Vertical Beam Size in the ANKA Storage Ring with an In-air X-ray Detector
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1073 |
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- A.-S. Müller, I. Birkel, E. Huttel, P. Wesolowski
FZK, Karlsruhe
- K.B. Scheidt
ESRF, Grenoble
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A major part of the X-rays generated in the ANKA dipole magnets is unused by the experimental beamlines and is, on a number of dipoles, absorbed in a conical shaped Copper absorber. The 8 mm thickness that it presents lets a tiny fraction of the hard X-rays above 70KeV enter the free air space behind it. The transmitted power of only a few uW/mrad hor. is sufficient to be detected, with sub-second measurement time, by a novel In-Air X-ray detector. This extremely compact and low-cost device is situated just behind the absorber. The design, developed and in use at the ESRF, is based on a Cadmium Tungstenate (CdWO4) scintillator converting X-rays into visible light that is collected and focused onto a commercial CCD camera. Since the small vertical divergence of the high energy photons and the distance of the detector from the source point are known, it is possible to derive the vertical electron beam size with a high intrinsic precision. This paper presents results of beam size measurements as a function of various ANKA machine parameters, that illustrates the great diagnostic potential of this type of detector for a 2.5GeV medium energy light source like ANKA.
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| THPLS011 |
Operation and Recent Development at the ESRF
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3290 |
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- J.-L. Revol, J.C. Biasci, J-F. B. Bouteille, J. Chavanne, P. Elleaume, L. Farvacque, L. Hardy, J. Jacob, G.A. Naylor, E. Plouviez, A. Ropert, K.B. Scheidt
ESRF, Grenoble
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We report on the achieved performance of the ESRF storage ring as well as developments accomplished or underway. A new hybrid filling mode based on groups of bunches and a 4-bunch filling pattern are now delivered to the users. Following the increasing demand of users for beam stability, the fast orbit feedback has been upgraded. The installation of 5 m-long, 8 mm vertical aperture NEG coated aluminum chambers is progressing at a rate of one chamber per shutdown. The increase in current from 200 to 300 mA is being prepared; however, operation in this mode is still impaired by HOM driven longitudinal instabilities. To overcome this difficulty, a longitudinal feedback is being commissioned. HOM damped cavities are also under study to possibly replace the existing five-cell cavities. The policy of preventive maintenance has been continued. However, in 2005 the machine availability was affected by water leaks occurring on front-end absorbers and on one dipole crotch absorber. The crotch absorbers suffer all from the same erosion process that could be delayed by a systematic vertical realignment, leaving time for procurement and replacement of the entire pool.
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