Testing Results for Nb-Ti, 120-mm-Aperture, Low-B Quadrupole Models for the LHC High-Luminosity Insertion

Abstract

The design and construction of a 120 mm wide-aperture, Nb-Ti superconducting quadrupole magnet for the LHC insertion region is part of a study towards a luminosity upgrade of the LHC at CERN, envisaged for 2020-22. The main challenges for this accelerator quality magnet are to operate reliably with the high heat and radiation loads that

Design Studies for the Low-Beta Quadrupoles for the LHC Luminosity Upgrade

“…This was the starting point of our analysis, were we considered two 140-mm-aperture lay-outs, the first one with the Nb 3 Sn technology (MQXF) and a back-up with Nb-Ti (MQXD). Both cases are a scaling of existing 120-mm-aperture short models, one in Nb 3 Sn (HQ, a 0.8-m-long model built by LARP and tested in several versions [6]), and one in Nb-Ti (MQXC, 1.8-m-long model built at CERN and recently tested [8]). Since HQ and MQXC are in an advanced stage of development, and present many of the technological features needed for this application, we also considered two lay-outs based on this aperture.…”

Magnet Design of the 150 mm Aperture Low-<formula formulatype="inline"><tex Notation="TeX">$\beta$</tex> </formula> Quadrupoles for the High Luminosity LHC

“…With an aperture of 120 mm and an operating gradient of 118 T/m, the magnet was characterized by a twolayer coil wound with the 15 mm wide cables from the LHC main dipoles and it used self-supporting collars. In two consecutive tests MQXC reached the nominal gradient [21], [22]. Simultaneously to the development of MQXC, LARP started working on a Nb 3 Sn quadrupole for the "Phase-II" luminosity upgrade.…”

CLIQ : a new quench protection technology for superconducting magnets

“…The example is based on the geometry of a Nb-Ti quadrupole accelerator magnet composed of four blocks of windings in two layers [83,106,109,110]. Let P1-P4 be the four magnet poles, ordered counter-clockwise.…”

“…Figure 2.4 shows the initial magnetic field distribution B a,0 in the quadrupole coil cross-section, assuming an initial current of I 0 =12.6 kA, corresponding to the magnet nominal current. The enthalpy per unit volume W q [Jm −3 ] required to initiate a transition to the normal state, shown in figure 2.5, is calculated based on this magnetic-field distribution, an initial homogeneous temperature of T 0 =1.9 K, and the physical properties of the conductor [109,110]. At this current level it ranges between 50 µJmm −3 in the high-field inner layer and 220 µJmm −3 in the low-field, mid-plane outer region.…”

“…CLIQ is tested on the 1.6 m long, 8.4 mH, Nb-Ti quadrupole model magnet for the LHC upgrade [83,106,109,110], whose cross-section and magnetic field distribution are presented in figure 2.4. Given the electrical order of the poles, an optimized 1-CLIQ Crossed-Pole configuration, like the one shown in figure 3.11e, is applied with a single CLIQ terminal connected to the midpoint of the coil.…”