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Measurement and interpretation of the bunched beam transfer function in SIS-18 with space charge

Chorniy, Oleksandr (2008):
Measurement and interpretation of the bunched beam transfer function in SIS-18 with space charge.
Darmstadt, Technische Universität, TU Darmstadt,
[Ph.D. Thesis]

Abstract

Longitudinal Beam Transfer Function (BTF) measurements are employed as a diagnostic tool to determine synchrotron frequencies and damping rates in a synchrotron. The BTF method is employed to measure an effective impedance. The aim of our theoretical study was to understand the influence of space charge effects and longitudinal impedances on the BTF. The BTF models developed in this work are based on the linearized Vlasov equation and on the equation of motion for a driven oscillator with damping factor. To verify the theoretical models numerical simulations studies have been performed. For these studies a PIC (particles-in-cell) code has been developed. As part of this work longitudinal BTF measurements using bunched beams were per- formed in the SIS. In the experiment we excited the bunches using rf phase modulation. The longitudinal bunch oscillations were detected as a function of the rf phase modulation frequency. The measurements were done at different beam intensities. For the interpreta- tion of experimental results the theoretical framework developed in this work was used.

Item Type: Ph.D. Thesis
Erschienen: 2008
Creators: Chorniy, Oleksandr
Title: Measurement and interpretation of the bunched beam transfer function in SIS-18 with space charge
Language: English
Abstract:

Longitudinal Beam Transfer Function (BTF) measurements are employed as a diagnostic tool to determine synchrotron frequencies and damping rates in a synchrotron. The BTF method is employed to measure an effective impedance. The aim of our theoretical study was to understand the influence of space charge effects and longitudinal impedances on the BTF. The BTF models developed in this work are based on the linearized Vlasov equation and on the equation of motion for a driven oscillator with damping factor. To verify the theoretical models numerical simulations studies have been performed. For these studies a PIC (particles-in-cell) code has been developed. As part of this work longitudinal BTF measurements using bunched beams were per- formed in the SIS. In the experiment we excited the bunches using rf phase modulation. The longitudinal bunch oscillations were detected as a function of the rf phase modulation frequency. The measurements were done at different beam intensities. For the interpreta- tion of experimental results the theoretical framework developed in this work was used.

Place of Publication: Darmstadt
Publisher: Technische Universität
Divisions: 18 Department of Electrical Engineering and Information Technology
Date Deposited: 17 Oct 2008 09:23
Official URL: urn:nbn:de:tuda-tuprints-10769
License: Creative Commons: Attribution-Noncommercial-No Derivative Works 3.0
Referees: Weiland, Prof. Dr.- Thomas and Boine-Frankenheim, Prof. Dr. Oliver
Refereed / Verteidigung / mdl. Prüfung: 15 April 2008
Alternative Abstract:
Alternative abstract Language

Messungen der longitudinalen Beam Transfer Function (BTF) werden eingesetzt zur Bestimmung der Synchrotronfrequenzen und der Dampfungsraten in Synchrotrons. Weiterhin kann die BTF Methode zur Messung der effektiven Impedanz, die auf einen Bunch wirkt, benutzt werden. Ziel des theoretischen Teils der vorliegenden Arbeit ist die Charakterisierung der Effekte der Raumladung und longitudinaler Impedanzen auf die BTF. Die BTF Modelle in dieser Arbeit basieren auf der linearisierten Vlasovgleichung sowie auf vereinfachten Oszillator- modellen mit Dämpfungsfaktoren. Zur Überprüfung der theoretischen Modelle wurden numerische Simulationen mit Particle-In-Cell (PIC) Methoden durchgeführt. Im Rahmen des experimentellen Teils dieser Arbeit wurden longitudinale BTF Messungen an gebunchten Ionenstrahlen im SIS-18 Synchrotron durchgeführt. Für diese Messungen wurden die Bunche mittels einer Modulation der HF Phase angeregt. Die resultierenden Bunchschwingungen wurden als Funktion der Modulationsfrequenz aufgezeichnet. Die Messungen wurden für verschiedene Strahlintensitäten durchgeführt. Die Interpretation der Messergebnisse erfolgte im Rahmen der in dieser Arbeit entwickelten theoretischen Modelle.

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