Sector Assembly Tests ATLAS New Small Wheel

During the thesis, I worked on the sector assembly where the different plates of the New Small Wheel detector will be connected together. The main question is: “How to minimize the deformation in the total sector while assembling the small Thin Gap Chamber on the MicroMegas?” To found the answer on the question is done desk research and simulations. At the end, the results will be checked with a sector assembly test with laser survey. The most imported factor during the assembly is to minimize the deformation during the complete assembly steps. The imported parts of the sector are the spacer-frame, MicroMegas detectors (MM) and the small-strips Thin Gap Chambers (sTGC). All the different detectors (MM and sTGC) have their own connection with the spacer-frame. The deformation in the wedges and frame is within the tolerance. The total deformation is 706µm. The individual deformation is less than the total acceptable deformation. The deformations get higher when the sector is in a swing. The advice is to minimize the swing when the sector is hanging on two points during the complete assembly with cables. A pillar is designed to fix the sector in Z direction and stop form swinging. Finally, to reach a higher precision on the connection points from the sTGC connections tolerances are changed, also the assembly station is updated. To proof that the deformation of the sector assembly is within the tolerances a survey measurement with a laser tracker was done during the sector assembly. The behaviour of the deformation is as expected. With a total deformation of 1300 µm, the extent is higher because of using dummy detectors and small mistakes during the assembly. For the serial production, the assembly must be done precise and with care to avoid mistakes.