Structure for an LHC 90 mm Quadrupole Magnet

A full-scale mechanical model of the LHC quadrupole magnet structure has been designed, built and tested. The structure will support a 90 mm bore, lm long magnet prototype as part of the US LHC Accelerator Research Program (LARP). The structure utilizes Bladder and Key Technology to control and transfer pre-stress from an outer aluminum shell to an inner coil. Axial aluminum rods take care of pre-stress at the ends—ensuring that the coil is fully constrained along all three axes. The outer alu- minum shell and an inner "dummy coil" (aluminum tube) were ex- tensively instrumented with strain gauges. The gauges were used to monitor and map the effectiveness of the stress relation between the loading structure and a "dummy" coil through varying mechanical load conditions—from bladder and key pre-stress at room temper- ature through cool-down. Test results of the stress distribution in the structure and the in dummy coil is reported and compared with expected results calculated with the structural analysis program ANSYS.