Ackermann, W.

Angelovski, A.

Hansli, M.

Hülsmann, P.

Jakoby, R.

Kaufmann, W.

Müller, W.

Penirschke, A.

Schwickert, M.

Weiland, T.

GSI Repository

Demonstration of the Sensitive Schottky-System for CR ∗A. Penirschke1, M. Hansli1, W. Kaufmann2, P. Hu¨lsmann2, M. Schwickert2, A. Angelovski1,W. Ackermann3, W. Mu¨ller3, T. Weiland3, and R. Jakoby11IMP, TU Darmstadt, Germany; 2GSI, Darmstadt, Germany; 3TEMF, TU Darmstadt, GermanyIntroductionThis report summarizes the development of a sensitivelongitudinal and transversal Schottky-Sensor for the Col-lector Ring CR at FAIR. Based on the equivalent circuitmodel, numerical simulations with CST Microwave Stu-dio, controlled by MATLAB were accomplished to opti-mize the performance of the sensor structure to the needsof the CR. To demonstrate the performance, a scaled non-hermetic demonstrator was optimized, fabricated and char-acterized.Schottky-System DesignResonant cavities exhibit excellent performances withmoderate size for schottky measurements at the ESR [1].The evaluation of the monopole mode TM010 and thedipole mode TM110 allows longitudinal as well as transver-sal schottky measurements. Due to the weak excitation ofthe dipole mode, both modes need to be coupled out in-dependently and, to suppress the monopole mode for theextraction of the transversal signal, rectangular waveguideresonators are foreseen for the CR [2, 3].Figure 1: Non-hermetic demonstrator with a beampipe di-mension of 46.5mm.Structure OptimizationDue to the strong inter-dependence of the relevant pa-rameters and the complex structure, the sensor system can-not be separated into subsystems. To optimize the cou-pling geometry, the simulations with CST Microwave stu-dio are iteratively controlled by MATLAB. The algorithmoptimizes the length of the waveguide for maximum cou-pling between the pillbox and the waveguide resonators un-der condition that the monopole mode is kept constant at200MHz, which can be adjusted by the radius of the pill-box. The algorithm closes with the adaption of the couplinggeometry, until the goal, the maximum gradient of the RQ -value of the dipole mode is achieved.∗Work supported by BMBF: 06DA90351Figure 2: Simulated and measured S-parameters.Non-hermetic demonstratorTo prove the simulation results, a non hermetic demon-strator scaled down by a factor of 8.6 was realized at TUDarmstadt (see ﬁg.1). S-parameter results exhibit verygood agreement between simulation and measurement (ﬁg.2). Preliminary perturbation measurements of the systemexhibits good agreement with the expected behavior forboth, the longitudinal and transversal detection (ﬁg. 3).Figure 3: Preliminary results of the perturbation measure-ments.Summary and OutlookAn iterative optimization algorithm based on Matlabcontrolled CST Microwave Studio simulations have beenveriﬁed by a realized non-hermetic demonstrator. The op-timization of the sensor geometry for the CR is ongoing.References[1] F. Nolden et al., “A Fast and Sensitive Resonant SchottkyPick-up for Heavy Ion Storage Rings”, Nuclear Instrumentsand Methods in Physics Research Section A, 2011.[2] M. Hansli, et al., “T. Conceptual Design of a high SensitiveVersatile Schottky Sensor for the Collector Ring at FAIR ,Proceedings DIPAC11, 2011[3] M. Hansli, et al., “Coupling Methods for the Highly Sensi-tive Cavity Sensor for Longitudinal and Transverse SchottkyMeasurements, Proceedings BIW12, 2012PNI-ACC-10 GSI SCIENTIFIC REPORT 2012366 FAIR@GSI

Demonstration of the Sensitive Schottky-System for CR

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Demonstration of the Sensitive Schottky-System for CR

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