Optimization of Chemical Etching Process in Niobium Cavities

Document Type

Conference Proceeding

Publication Date


Publication Title

2004 ASME Design Engineering Technical Conferences and Computers and Information in Engineering Conference


American Society of Mechanical Engineers

First page number:


Last page number:



Superconducting niobium cavities are important components of linear accelerators. Buffered chemical polishing (bcp) on the inner surface of the cavity is a standard procedure to improve its performance. The quality of bcp, however, has not been optimized well in terms of the uniformity of surface smoothness. A finite element computational fluid dynamics (cfd) model was developed to simulate the chemical etching process inside the cavity. The analysis confirmed the observation of other researchers that the sections closer to the axis of the cavity received more etching than other regions. A baffle was used by lanl personnel to direct the flow of the etching fluid toward the walls of the cavity. A new baffle design was tined using optimization techniques. The redesigned baffle significantly improves the performance of the etching process. To verify these results an experimental setup for flow visualization was created. The setup consists of a high speed, high resolution ccd camera. The camera is positioned by a computer-controlled traversing mechanism. A dye injecting arrangement is used for tracking the fluid path. Experimental results are in general agreement with computational findings.


Computational fluid dynamics; Etching; Grinding and polishing; Holes; Linear accelerators; Niobium; Surfaces


Fluid Dynamics | Materials Science and Engineering | Mechanical Engineering | Nuclear Engineering




Conference held: Salt Lake City, Utah, USA, September 28–October 2, 2004


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