Assembly Tests of the First Nb3Sn Low-beta Quadrupole Short Model for the Hi-Lumi LHC (original) (raw)

In preparation for the high luminosity upgrade of the Large Hadron Collider, the LHC Accelerator Research Program (LARP) in collaboration with CERN is pursuing the development of MQXF: a 150 mm aperture high-field Nb 3 Sn quadrupole magnet. The development phase starts with the fabrication and test of several short models (1.2 m magnetic length) and will continue with the development of several long prototypes. All of them are mechanically supported using a shell-based support structure, which has been extensively demonstrated on several R&D models within LARP. The first short model MQXFS-AT has been assembled at LBNL with coils fabricated by LARP and CERN. In this paper, we summarize the assembly process and show how it relies strongly on experience acquired during the LARP 120 mm aperture HQ magnet series. We present comparison between strain gauges data and finite element model analysis. Finally we present the implication of the MQXFS-AT experience on the design of the long prototype support structure.  Index Terms-High Luminosity LHC (HL-LHC), Interaction Regions, quadrupole, LARP, Nb 3 Sn magnet, shell-based support structure, short model. I. INTRODUCTION HE LARGE HADRON COLLIDER is preparing for the High Luminosity Upgrade. Key components of this upgrade are the Interaction region Low- Quadrupoles Q1, Q2 and Q3 [1]. The 150 mm aperture Nb 3 Sn magnets are developed in collaboration between the US-LARP (LHC Accelerator Research Program) and CERN. In this framework, the US is in charge of the ten Q1 and Q3 cold masses; each of them being made out of two 4.9 m long magnets called MQXFA. Each MQXFA magnet has a magnetic length of 4.2 m at cold and is assembled in a stand-alone support structure [2]. The development of these magnets follows a two-step process with the fabrication, assembly and test of the short (MQXFS) and the long prototypes (MQXFA). The MQXFS prototypes are built in collaboration between CERN and LARP, whereas the long prototypes are under the US responsibility. In the past months, mechanical models of the short magnets using aluminum false coils have been assembled and cooled down to validate the support structure both at CERN and within LARP. Results showing excellent agreement between strain gauges data and analysis are Manuscript received