Construction and cold test of the superferric decapole for the LHC Luminosity upgrade

The National Institute for Nuclear Physics (INFN) is developing at the Laboratory of Accelerators and Applied Superconductivity (LASA) laboratory (Milano, Italy) the prototypes of five corrector magnets, from skew quadrupole to dodecapole, which will equip the high-luminosity interaction regions of the High Luminosity Large Hadron Collider (HL-LHC). These magnets are based on a superferric design, which allows a relatively simple, compact, and easy to construct magnet. This activity takes place within the framework of a collaboration agreement between European Organization for Nuclear Research (CERN) and INFN. The first prototypes, a sextupole and an octupole, have been tested in 2016 and 2017, respectively. We present here the results of the cold tests of the decapole that has been assembled and tested in the second half of 2017, including the training performed at 4.2 K and the qualification at 2.17 K. We report also on the overall experience gained during construction and tests and the improvements toward the series production. Other important results concern quench studies.