Tests of a 70 mm aperture quadrupole for the LHC low-$\beta$ insertions

Three 70 mm aperture 1-meter superconducting quadrupole magnets for the LHC low- beta insertions have been designed and built in collaboration between CERN and Oxford Instruments. These magnets feature a four layer coil wound fromtwo 8.2 mm wide graded NbTi cables. In this paper, the authors present the results from the tests at 4.4 K and 1.9 K of the third quadrupole (Q3), with an emphasis on studies concerning quench protection. After a summary of Q3 training in three thermal cycles, quench velocities, peak temperatures in the two superconducting cables and the performance of the layer strip heaters are reported. (6 refs).