Mobile CT-System for In-situ Inspection in the LHC at CERN

At the European Organisation for Nuclear Research ( CERN) the worlds largest particle accelerator ring, the Large Hadron collider (LHC), is being put into operation. It has been found useful to have a tool for diagnosis of the st ate of components in the interconnection regions of the LHC. This tool, for non-destructive testing (NDT) must w ork without opening the interconnection elements, without breaking the inte grity of the vacuum, and without the need to warm up the sector which would be costly an d time consuming. In addition the NDT tool has to be transportable in order to positi on it anywhere around the 27 km long LHC ring. The approach is an X-Ray inspection with the aim of an unambiguous representation of all structural elements in the interconnection regi ons of the LHC ring. The minimum criterion is to achieve an inspection result which allows verification of the correct position and integrity of all important components. 3D X-Ray computed tomography (3D CT) would be the i deal solution for such an inspection task. But due to the constraints in the LHC tunnel, especially the very limited space behind the LHC ring it is not possible to mov e an X-Ray source and a digital X- Ray detector completely around the interconnections . Therefore it was necessary to develop a mobile 3D X-Ray system which allows for a maximum scanning versatility within the given constraints and provide 3D results based on limited scan angles. Such a mobile X-Ray system is presented in this pap er as well as results from the inspections of the LHC ring interconnections. In addition it will be outlined how the approach us ed in this system could be applied to other applications.