The design of high current RFQ\'s is heavily strained by thermo-mechanical considerations, which eventually have an impact on machining costs, cooling systems, etc. A 1-meter long copper prototype of the SPIRAL2 RFQ has been specifically built to corroborate design options. An innovative method has been developed, allowing real-time observation of mechanical deformations of RFQ vanes, with full-scale RF power and water cooling. Digital images are acquired by a CCD camera, and processed by a dedicated software. Processing includes contrast stretching, low-pass filtering, and block-correlation followed by interpolation. Sub-pixel relative motions of RFQ electrode ends are clearly detected and measured, with RMS errors in the range 0.6 to 1.8 micron. |
