North Central College, Physics, Aurora, IL 60502
For a number of superconducting quadrupole magnets that have been built and tested at Fermi National Accelerator Laboratory for installation at the Large Hadron Collider (LHC) Interaction Regions, several of them did not reach the target operating current of 12208A. The systematic study of the available quench data has been performed in order to localize the problem region and understand the reason behind the current limitations. The quench antenna seems to give a consistent location for the quenches in the limited magnets, where there are few voltage taps to do this. However, it has not yet been shown whether the antenna can distinguish quenches that originate in the Inner coil from those starting in the Outer coil. As a result, we turn to existing data from High Gradient Quadrupole (HGQ) model magnet program and use information provided from both voltage taps and quench antennas to determine the radial and angular quench positions. We studied three magnets to specifically evaluate the antenna results for Inner versus Outer quenches. The obtained data led to the conclusion that quenches originating in the Inner coil cannot be distinguished using the quench antenna from those starting in the Outer coil. It has been observed that the calculated radius for Outer coil quenches points to the Inner coil region. Moreover, angle measurements don’t appear to be consistent with expectations for all three antenna sections.
[Abstract (DOC)]