| Paper |
Title |
Page |
| MOPKF013 |
The Influence of the Main Coupler Field on the Transverse Emittance of a Superconducting RF Gun
|
327 |
| |
- D. Janssen
FZR, Dresden
- M. Dohlus
DESY, Hamburg
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For the Rossendorf superconducting RF gun project the influence of the additional RF field, created in the cavity by the RF power flow at the main coupler, is discussed. One end of the gun cavity is occupied by the cathode insert, so all flanges are concentrated on the other end. In the "flange plane" of the cavity two HOM coupler, the pic up and the main coupler are located. If we normalize the RF field in the cavity by the condition Eacc = 25MV/m and assume a beam power of 10kW (CW mode), we obtain an quality factor Qext = 2.2*10**7. A three dimensional field calculation using the MAFIA code, gives the field perturbation near the main coupler. Tracking calculation with ASTRA show,that this perturbation increases the transversel emittance between 1 and 4%, nearly independent from the bunch charge. This result shows, that for average beam powers in the vicinity of 10kW effects, connected with the assymetric input of RF power can be neglected.
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| MOPKF018 |
Injector and Bunch Compressor for the European XFEL Project
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342 |
| |
- Y. Kim, Y. Kim, D. Son
CHEP, Daegu
- M. Dohlus, K. Floettmann, T. Limberg
DESY, Hamburg
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For the proper operation of European XFEL project, we should supply high quality electron beams with low emittance, short bunch length, and low energy spread to a 200 m long undulator. In this paper, we describe the optimization and design concepts of the XFEL injector and bunch compressors to control the beam parameter dilution due to the microbunching instability and CSR.
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| WEPLT062 |
Wakefield Calculations for TTF-II
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1984 |
| |
- I. Zagorodnov, T. Weiland
TEMF, Darmstadt
- M. Dohlus
DESY, Hamburg
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In this paper we estimate long- and short-range wake functions for new elements to be used in TESLA Test Facility (TTF) - II. The wake potentials of the LOLA-IV structure and the 3rd harmonic section are calculated numerically for very short bunches and analytical approximations for wake functions in short and long ranges are obtained by fitting procedures based on analytical estimations. The numerical results are obtained with code ECHO for high relativistic Gaussian bunches with RMS deviation up to 0.015 mm. The calculations are carried out for the complete structures (including bellows, rounding of the irises and the different end cell geometries) supplied with ingoing and outgoing pipes. The low frequency spectra of the wake potentials is calculated using the Prony-Pisarenko method.
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