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MOP023 |
Theoretical and Practical HOM-Analysis of the Rossendorf SRF Gun | |
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| The success of future synchrotron radiation sources and high power IR free-electron lasers (FELs) largely depends on the development of an appropriate electron source. To this moment, the superconducting radio frequency photoinjector (SRF gun) seems to be a promising candidate to achieve the required brightness and the high average current at the same time. In contrast to normal conducting DC and RF guns, now multi-bunch effects of higher order modes (HOM) and their influence on beam quality are of particular interest. For this reason, we present a method that considers the accelerated motion of the nonrelativistic electrons in the gun cavity to calculate the longitudinal and transverse coupling impedances. Based on this results the required loaded quality factors to reduce the excited fields of the HOMs are determined. Additionally, a second method is discussed using both cavity tuners for selective detuning of the eigenmode spectra, while the fundamental mode frequency is keeping constant. Finally, the results are compared with first beam-based measurements at the existing SRF gun at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR). | ||
| MOP025 | The SRF Photo Injector at ELBE – Design and Status 2013 | 148 |
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Funding: EuCARD, contract number 227579, German Federal Ministry of Education and Research grant 05 ES4BR1/8 In order to improve the gradient of the cavity and the beam quality of the gun, a new design for the SRF photo injector at the Helmholtz-Zentrum Dresden-Rossendorf has been developed. Apart from the special design of the cavity itself – as presented at SRF09, Berlin – the next update will include a separation of input and output of the liquid nitrogen supply system. This is supposed to increase the stability of the nitrogen pressure and enable a better monitoring of its temperature. The implementation of a superconducting solenoid inside the cryomodule is another major improvement. The position of this solenoid can be adjusted with a high precision using two independent step motors, which are thermally isolated from the solenoid itself. The poster will present the progress of turning the first design models into reality. |
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| MOP026 | Emittance Compensation for an SRF Photo Injector | 151 |
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Funding: European Community-Research Infrastructure Activity under the FP7 program (EuCARD, contract number 227579), German Federal Ministry of Education and Research grant 05 ES4BR1/8 A lot of the future electron accelerator projects such like ERLs, high power FELs and also some of the new collider designs rely on the development of particle sources which provide them with high average beam currents at high repetition rates, while maintaining a low emittance. SRF photo injectors represent a promising concept to give just that, offering the option of a continuous wave operation with high bunch charges. Nevertheless, emittance compensation for these electron guns, with the goal to reach the same level as normal conducting sources, is an ongoing challenge. The poster is going to discuss several approaches for the 3-1/2-cell SRF gun installed at the accelerator facility ELBE at the Helmholtz Center Dresden-Rossendorf including the installation of a superconducting solenoid within the injector’s cryostat and present the currently used method to determine the beam’s phase space. |
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