Pulse Ripple Research Articles

New spiral beam screen design for the FCC-hh injection kicker magnet

The injection kicker system for the Future Circular Collider (FCC-hh) must satisfy demanding requirements. To achieve low pulse ripple and fast field rise and fall times, the injection system will use ferrite loaded transmission line type magnets. The beam coupling impedance of the kicker magnets is crucial, as this can be a dominant contribution to beam instabilities. In addition, interaction of the high intensity beam with the real part of the longitudinal beam coupling impedance can result in high power deposition in the ferrite yoke. This gives a significant risk that the ferrite yoke will exceed its Curie temperature: hence, a suitable beam screen will be a critical feature. In this paper, we present a novel concept - a spiral beam screen. The fundamental advantage of the new design is a significant reduction of the maximum voltage induced on the screen conductors, thus decreased probability of electrical breakdown. In addition, the longitudinal beam coupling impedance is optimized to minimize power deposition in the magnet.

Theoretical analysis of the stretched optical pulse ripple and novel chirped pulse retrieving algorithm.

Amplitude and phase ripples of an ultrafast chirped pulse complex envelope are considered. The formula that establishes the relation between the pulse complex envelope and its spectrum amplitude was theoretically derived for both cases of the ripple. Based on current results, a linearly chirped pulse can be retrieved using only a spectrum analyzer and Kerr nonlinear medium.

Design of an Ultraprecise 127-MW/3- Solid-State Modulator With Split-Core Transformer

This paper presents the design of an ultraprecise 127-MW/3- $\mu \textrm {s}$ solid-state modulator with split-core transformer. The modulator consists of a power supply, 12 pulse generator modules with active core reset, and a split-core transformer with six cores. In addition, an $LC$ bouncer could be used to compensate the droop of the pulse. This paper includes the design and analysis of the pulse transformer. A volume minimal transformer is investigated for different load capacitances to investigate the achievable rise time and the parameters which can be used to adjust the damping. In addition, the influence of the pulse transformer on the synchronization of the switches is investigated using an enhanced reluctance model. In addition, an $LC$ bouncer circuit is investigated. A multiobjective optimization is performed which shows the required energy of the bouncer for a certain pulse ripple. The flat-top ripple of the presented modulator can be reduced to 0.2%. Because the bouncer degrades the flat-top stability, the bouncer is not implemented. Measurements of the overall system include short-circuit measurements and flat-top stability measurements. They show that the modulator is short-circuit capable. Furthermore, the flat-top stability is determined to be less than 10 ppm at an output voltage of 360 kV.