Developing a Multipacting-free Cathode Unit for a Superconducting RF Photoinjector (SRF gun)

Electron multipacting (MP) is one of the recent difficulty for the SRF gun. Thus, among the several ongoing investigations on this phenomenon, the experimental results indicates that the high MP current has been measured in the cathode unit of the SRF gun at Helmholtz-Zentrum Dresden- Rossendorf research institute. This reduces the efficiency of the SRF system operation by limiting the accelerating gradient in the cavity. Moreover, it might cause an impair of RF components and distortion of the RF signal. The goal of this project is to develop a new cathode unit of SRF gun as a countermeasure to suppress multipacting.

• Numerical simulation of electromagnetic field and multipacting for Rossendorf SRF gun
• Develop a new cathode unit of SRF gun in cooperation with HZDR and HZB, 
• A parametic numerical sensivity studies of the newly designed cathode unit based on stochastic approach
• A Monte Carlo calculation of secondary electron emission coefficient using experimental data in cooperation with University of Siegen

Peer Reviewed Conference Papers:

E. Tafa Tulu, A. Arnold and U. van Rienen. 3D CST Simulation to Understand Multipacting. 16th International Conference on RF Superconductivity, accepted on 16th of July. Paris, France.

E. Tafa Tulu, A. Arnold and U. van Rienen. Different Countermeasures of Electron Amplification in the  Photocathode Unit, Proceedings of IPAC2014, Dresden, Germany. 

Workshop and Meeting Presentations: 

E. Tafa Tulu, A. Arnold, U. van Rienen: Simulation Study on Multipacting Processes in the Rossendorf SRF Gun, 16th Int. Conf. on RF Superconductivity (SRF 2013), Sept. 22-27, Paris, France

E. Tafa Tulu, Gisela Pöplau and U. van Rienen. Numerical Studies of Designs of Clearing Electrodes for Ion Clearing in an ERL, 77th Annual Meeting of the DPG, March 2013, Dresden, Germany.

E. Tafa Tulu, Gisela Pöplau and U. van Rienen. Numerical Studies of Designs of Clearing Electrodes for Ion Clearing in an ERL, KWT 2013, Austria.

E. Tafa Tulu, A. Arnold and U. van Rienen. Multipacting Study in the Rossendorf Superconducting RF Gun (SRF Gun), kickoff meeting 2013, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany.

E. Tafa Tulu and U. van Rienen. Multipacting-freie Kathodeneinheit für supraleitende Hochfrequenz Photoinjektoren (SINEMP), Forschungscamp 2013, University of Rostock, Germany.

E. Tafa Tulu, A. Arnold, Tomasz Galek and U. van Rienen. Suppression Methods of Multipacting in a Superconducting RF Gun, DPG-Tagungen 2014, Dresden, Germany.

E. Tafa Tulu, A. Arnold and U. van Rienen. Multipacting Analysis and Suppression Techniques for Superconducting RF Gun, HOPE-SINEMP meeting 2014, University of Siegen, Siegen, Germany.

E. Tafa Tulu and U. van Rienen. Parametric Study of Superconducting RF Gun, Hope-SINEMP Meeting 2014, University of Rostock, Germany. 

Eden Tafa Tulu, Prasanth Babu Ganta, André Arnold and Ursula van Rienen. Studies on a Modified Cathode Tip for the ELBE Superconducting RF Gun, DPG-Tagungen 2016, Darmstadt, Germany.

E. Tafa Tulu and U. van Rienen. Multi-Dimensional Optimization of Groove Parameters for the Cathode Tip, AG Workshop 2016, Wustrow, Germany.

E. Tafa Tulu and U. van Rienen. Multi-Dimensional Optimization of Groove Parameters for the Cathode Tip, Hope-SINEMP Meeting 2016, Darmstadt, Germany. 

• Prof. Dr. rer. nat. habil. Ursula van Rienen
• Dr. André Arnold