IPAC2011 - List of Authors (Aderhold, S.)

Paper	Title	Page
MOPC085	Quality Assessment for Industrially Produced High-Gradient Superconducting Cavities	274
	F. Schlander, S. Aderhold, E. Elsen, D. Reschke, M. Wenskat DESY, Hamburg, Germany
	Funding: This work is supported by the Commission of the European Communities under the 7th Framework Programme “Construction of New Infrastructures – Preparatory Phase”, contract number 206711. A series of some 600 superconducting 1.3 GHz cavities will start being delivered to DESY by industry in early 2012. Although a considerably smaller gradient satisfies the needs for the European XFEL the electro-polished cavities (50% of the delivery) are deemed to be suitable for gradients in excess of 35 MV/m, the performance goal of the International Linear Collider (ILC). Specifically 24 cavities will be supplied without helium tank to enable further investigations. The results may serve to improve overall performance; limitations such as field emission and thermal breakdown of superconductivity ("quench") are still under investigation. For this matter the DESY ILC group has developed tools to monitor aspects of the cavity fabrication. An automated optical mapping system (OBACHT) is being commissioned and will be complemented by software for automated cavity surface feature recognition. For cold RF tests a Second Sound setup for locating the positions of the thermal breakdown is routinely used. These diagnostic tools will give guidance on post-processing cavities for best performance. The current status of these projects will be described.

TUPC033	Verifying the Single Bunch Capability of the New Injector at ELSA*	1072
	S. Mey, O. Boldt, W. Hillert, N. Hofmann, F. Klarner, D. Krönung, A. Roth, M. Schedler ELSA, Bonn, Germany S. Aderhold DESY, Hamburg, Germany
	Funding: Funded by the DFG within the SFB / TR 16 and the Helmholtz Alliance HA 10¹ "Physics at the Terascale". In order to enhance the operating capabilities of the Bonn University Accelerator Facility, ELSA, a new injector is currently under commissioning. One of its main purpose is to allow a single pulse mode. The injector produces a single electron bunch with 1.5 A pulse current. Design and optimization of the injector have been performed with EGUN, PARMELA and numerical simulations based on the numerical integration of the paraxial equation. A 1 ns long pulse is produced by a thermionic electron source with 90 kV anode - cathode voltage, then compressed and pre-accelerated by a subsequent 500 MHz RF cavity and a four-cell travelling wave buncher. Finally, the bunch will be accelerated to 20 MeV by the main LINAC section. Measurements have been conducted concerning the resulting pulse length and pulse charge to confirm the predictions made by simulations and to investigate the efficiency of the injector system.

Paper

Title

Page

Quality Assessment for Industrially Produced High-Gradient Superconducting Cavities

274

F. Schlander, S. Aderhold, E. Elsen, D. Reschke, M. Wenskat
DESY, Hamburg, Germany

Funding: This work is supported by the Commission of the European Communities under the 7th Framework Programme “Construction of New Infrastructures – Preparatory Phase”, contract number 206711.
A series of some 600 superconducting 1.3 GHz cavities will start being delivered to DESY by industry in early 2012. Although a considerably smaller gradient satisfies the needs for the European XFEL the electro-polished cavities (50% of the delivery) are deemed to be suitable for gradients in excess of 35 MV/m, the performance goal of the International Linear Collider (ILC). Specifically 24 cavities will be supplied without helium tank to enable further investigations. The results may serve to improve overall performance; limitations such as field emission and thermal breakdown of superconductivity ("quench") are still under investigation. For this matter the DESY ILC group has developed tools to monitor aspects of the cavity fabrication. An automated optical mapping system (OBACHT) is being commissioned and will be complemented by software for automated cavity surface feature recognition. For cold RF tests a Second Sound setup for locating the positions of the thermal breakdown is routinely used. These diagnostic tools will give guidance on post-processing cavities for best performance. The current status of these projects will be described.

TUPC033

Verifying the Single Bunch Capability of the New Injector at ELSA*

1072

S. Mey, O. Boldt, W. Hillert, N. Hofmann, F. Klarner, D. Krönung, A. Roth, M. Schedler
ELSA, Bonn, Germany
S. Aderhold
DESY, Hamburg, Germany

Funding: Funded by the DFG within the SFB / TR 16 and the Helmholtz Alliance HA 10¹ "Physics at the Terascale".
In order to enhance the operating capabilities of the Bonn University Accelerator Facility, ELSA, a new injector is currently under commissioning. One of its main purpose is to allow a single pulse mode. The injector produces a single electron bunch with 1.5 A pulse current. Design and optimization of the injector have been performed with EGUN, PARMELA and numerical simulations based on the numerical integration of the paraxial equation. A 1 ns long pulse is produced by a thermionic electron source with 90 kV anode - cathode voltage, then compressed and pre-accelerated by a subsequent 500 MHz RF cavity and a four-cell travelling wave buncher. Finally, the bunch will be accelerated to 20 MeV by the main LINAC section. Measurements have been conducted concerning the resulting pulse length and pulse charge to confirm the predictions made by simulations and to investigate the efficiency of the injector system.