BIW2012 - List of Authors (Hülsmann, P.)

Paper	Title	Page
MOPG001	Field Attenuation of the Magnetic Shield for a Cryogenic Current Comparator	17
	F. Kurian, P. Hülsmann, P. Kowina, D.A. Liakin, H. Reeg, M. Schwickert GSI, Darmstadt, Germany R. Geithner, R. Neubert FSU Jena, Jena, Germany W. Vodel HIJ, Jena, Germany
	Funding: Work supported by EU, DITANET, Project No. ITN-2008-215080 The upcoming FAIR facility requires measurements of very low ion currents during slow extraction from the synchrotron SIS100. A Cryogenic Current Comparator (CCC), with its capability to measure absolute ion beam currents non-destructively down to nA range, is foreseen to be installed in various locations of the high energy beam transport section of FAIR. The current resolution of the CCC is only limited by the system noise, mainly originating from the environmental electromagnetic fields and mechanical vibrations. A meander-shaped superconducting shield geometry covering the pick-up coil efficiently suppresses disturbing non-azimuthal field components. The attenuation of external magnetic field components by the shield in different field directions is studied for various geometrical and material parameters by means of an FEM simulation. The simulation results are compared with attenuation factors obtained by experiments.

TUPG008	Coupling Methods for the Highly Sensitive Cavity Sensor for Longitudinal and Transverse Schottky Measurements	149
	M. Hansli, A. Angelovski, R. Jakoby, A. Penirschke TU Darmstadt, Darmstadt, Germany W. Ackermann, T. Weiland TEMF, TU Darmstadt, Darmstadt, Germany P. Hülsmann, W. Kaufmann GSI, Darmstadt, Germany
	Funding: Work supported by the BMBF: 06DA90351 In order to observe rare isotopes and anti-protons in the Collector Ring (CR) at FAIR, a highly sensitive Schottky cavity sensor is proposed, utilizing the monopole mode for longitudinal and a dipole mode for transverse measurements. Because the charged particle beam excites the dipole mode in the suggested resonator several orders of magnitude smaller than the corresponding monopole mode, it is crucial to extract both components independently without mutual correlation. Particular focus has to be put on the extraction of the dipole mode to sufficiently suppress the strong monopole contribution by taking advantage of a frequency selective coupling mechanism. Utilization of waveguide filters at the measurement frequency of about 300 MHz results in a bulky structure. To reduce the size, different methods for coupling and filtering including dielectric filling of the waveguides are evaluated in this work with respect to their Signal-to-Interference-and-Noise-Ratio. Hereby, key parameters that influence the performance, namely, the shunt impedance of the dipole mode, the suppression of the monopole mode, and the noise behavior of the system are systematically analyzed and optimized.

Paper

Title

Page

Field Attenuation of the Magnetic Shield for a Cryogenic Current Comparator

17

F. Kurian, P. Hülsmann, P. Kowina, D.A. Liakin, H. Reeg, M. Schwickert
GSI, Darmstadt, Germany
R. Geithner, R. Neubert
FSU Jena, Jena, Germany
W. Vodel
HIJ, Jena, Germany

Funding: Work supported by EU, DITANET, Project No. ITN-2008-215080
The upcoming FAIR facility requires measurements of very low ion currents during slow extraction from the synchrotron SIS100. A Cryogenic Current Comparator (CCC), with its capability to measure absolute ion beam currents non-destructively down to nA range, is foreseen to be installed in various locations of the high energy beam transport section of FAIR. The current resolution of the CCC is only limited by the system noise, mainly originating from the environmental electromagnetic fields and mechanical vibrations. A meander-shaped superconducting shield geometry covering the pick-up coil efficiently suppresses disturbing non-azimuthal field components. The attenuation of external magnetic field components by the shield in different field directions is studied for various geometrical and material parameters by means of an FEM simulation. The simulation results are compared with attenuation factors obtained by experiments.

TUPG008

Coupling Methods for the Highly Sensitive Cavity Sensor for Longitudinal and Transverse Schottky Measurements

149

M. Hansli, A. Angelovski, R. Jakoby, A. Penirschke
TU Darmstadt, Darmstadt, Germany
W. Ackermann, T. Weiland
TEMF, TU Darmstadt, Darmstadt, Germany
P. Hülsmann, W. Kaufmann
GSI, Darmstadt, Germany

Funding: Work supported by the BMBF: 06DA90351
In order to observe rare isotopes and anti-protons in the Collector Ring (CR) at FAIR, a highly sensitive Schottky cavity sensor is proposed, utilizing the monopole mode for longitudinal and a dipole mode for transverse measurements. Because the charged particle beam excites the dipole mode in the suggested resonator several orders of magnitude smaller than the corresponding monopole mode, it is crucial to extract both components independently without mutual correlation. Particular focus has to be put on the extraction of the dipole mode to sufficiently suppress the strong monopole contribution by taking advantage of a frequency selective coupling mechanism. Utilization of waveguide filters at the measurement frequency of about 300 MHz results in a bulky structure. To reduce the size, different methods for coupling and filtering including dielectric filling of the waveguides are evaluated in this work with respect to their Signal-to-Interference-and-Noise-Ratio. Hereby, key parameters that influence the performance, namely, the shunt impedance of the dipole mode, the suppression of the monopole mode, and the noise behavior of the system are systematically analyzed and optimized.