Request for Information Questions and Answers

November 13, 2026

Request for Information 483335
Prototype Stripline Kickers
Questions and Answers

Question 1
Which sealing/joining concept shall be applied to connect the two halves of the body and the port connections to the body? We assume that, from a vacuum standpoint, vacuum brazing is the appropriate method. In this case, accessibility of the electrodes is difficult. We assume that vacuum requirements do not allow using O-rings. Please explain the planned concept. Answer
The ESR vacuum requirements call for all kicker parts to be brazed together. The concept of two half body shells shown in the original STEP geometry was an initial idea, but is probably not suited for this stripline kicker geometry. A central body with transition pieces at both ends is probably a better approach. An updated STEP geometry has been arranged to explain this concept. The inner structure of the central part would be wire-EDM cut and then brazed to the two end pieces, which would have to be milled. This concept was successfully implemented for the APS-U stripline kicker and, many years ago, for a series of shorter stripline BPMs at DESY FLASH. O-rings are not acceptable; everything has to be leak-tight brazed in accordance with the vacuum requirements.
Question 2
The wakefield-induced RF loss will heat the electrode assembly. We understand that heating is to be minimized by optimizing the liquid-cooling design, but even several Kelvin of heating may cause deformation, particularly where an assembly uses two different materials, such as stainless steel and copper. Would it be an option to make the coolant-guiding cover from OFHC? Answer
The beam-induced power dissipation is substantial and has been studied in detail. The associated temperature increase on the individual components has not been studied and is expected to be evaluated by the bidding company. To mitigate heating of the stripline electrodes, several strategies should be followed:
• Darken the electrode surface to increase thermal emissivity and radiation efficiency. A CuO blackening procedure was used successfully for the copper striplines of the APS-U kicker. • Add or integrate liquid-cooling channels on the stripline electrodes while maintaining the odd-mode characteristic impedance of the stripline pair. The cooling-channel cover may be the same material as the striplines; it must be brazed onto the striplines, or the stripline/cooling-channel structure must be manufactured from a single piece of metal. Small changes to the stripline/cooling-channel geometry