Pulse power modulator development for CERN's compact linear collider

Janne Holma

Research output: ThesisLicenciate's thesis


This thesis presents the design steps and a prototype for a high precision pulse power modulator. Prototyping of the pulse modulator is a part of the feasibility study of Compact Linear Collider (CLIC) study. The CLIC design relies on Pre-Damping Rings (PDR) and Damping Rings (DR) to achieve the very low emittance through synchrotron radiation. The pulse power modulators for the DR kickers must provide extremely flat, high-voltage pulses. The specifications of the 2 GHz baseline called for a 160 ns duration flattop of 12.5 kV, 250 A, with a combined ripple and drop of not more than +-0.02 %. In the beginning of the thesis, a literature review is presented to choose the topology for a high precision pulse power modulator. A modulator based on solid-state switches, the inductive adder, has been selected as the most promising approach to meeting the specifications. This topology allows the use of both digital and analogue modulation techniques. Then, the electrical and mechanical design of the inductive adder is presented, especially for matching the output impedance of the modulator to a load. The reasoning for selecting the main components for an inductive adder is also covered. The thesis also presents simulation studies of applying different compensation methods for achieving the required pulse waveform for the CLIC DR extraction kicker system. The design methods have been verified by building a prototype inductive adder and testing it with up to 1.4 kV output voltages. The simulations studies and the initial measurements have shown that the required high precision for CLIC DR kicker inductive adder is very probably feasible with the developed design.
Original languageEnglish
QualificationLicentiate's degree
Awarding Institution
  • Aalto University
  • J. Ovaska, Seppo, Supervising Professor
  • Barnes, Michael, Thesis Advisor, External person
Publication statusPublished - 2014
MoE publication typeG3 Licentiate thesis


  • Pulse power modulator
  • Inductive adder
  • Kicker system
  • Feasibility study


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