Title: Development of TQC01, a 90mm Nb3Sn model quadrupole for LHC upgrade based on ss collar
Abstract: Development of TQC01, a 90 mm Nb 3 Sn Model Quadrupole for LHC Upgrade Based on SS Collar R. C. Bossert, G. Ambrosio, N. Andreev, E. Barzi, S. Caspi, D. R. Dietderich, P. Ferracin, A. Ghosh, S. A. Gourlay, A. R. Hafalia, C. R. Hannaford, V. S. Kashikhin, V. V. Kashikhin, A. F. Lietzke, S. Mattafirri, A. D. McInturff, I. Novitski, G. L. Sabbi, D. Turrioni, G. Whitson, R. Yamada, and A. V. Zlobin Abstract—As a first step toward the development of a large-aper- ture superconducting quadrupole for the Large Hadron Collider (LHC) luminosity upgrade, two-layer technological quadrupole models (TQS01 at LBNL and TQC01 at Fermilab) are being constructed within the framework of the US LHC Accelerator Research Program (LARP). Both models use the same coil design, but have different coil support structures. This paper describes the TQC01 design, fabrication technology and summarizes its main parameters. Nb Sn Index Terms—Collars, LARP, LHC IR, magnet, skin, yoke. Nb 3 Sn , quadrupole I. I NTRODUCTION Fig. 1. TQ magnet coil cross section. N IMPORTANT objective of the US LHC Acceler- ator Research Program (LARP) is to develop a quadrupole for an eventual LHC upgrade [1]. US labs (FNAL, BNL and LBL) are collaborating to build and test the ini- tial short models. Two different structures, using the same two-layer, 90 mm aperture shell type epoxy impregnated coil design, are being pursued. The TQS01 structure was developed and tested on a dummy coil at LBNL. In this approach, coils are assembled and reacted against an outer aluminum shell using keys and bladders [2]. A short quadrupole model TQC01 based on stainless steel collars supported by an iron yoke and thick SS skin is being developed at Fermilab. A short 0.3 m long mechanical model is being fabricated and tested to verify the results of the mechanical analysis. The model is instrumented with strain gauges installed on its main components. Stress distribution is monitored during model assembly at room tem- perature and after cooling down to liquid nitrogen temperature. This paper describes the TQC01 design, fabrication technology and summarizes its main parameters. Initial coil fabrication experience is reported. ANSYS 2D calculations and measure- ments on a mechanical model are shown. A TABLE I TQ S PECIFICATIONS II. M AGNET D ESIGN AND A NALYSIS A. Cable and Cross Section The TQ coil design consists of a 2-layer configura- tion with a 90 mm bore and one wedge in the inner layer (Fig. 1). The cable design was developed in collaboration with BNL and LBNL [3]. It is made of 27 strands each .7 mm in dia., with a nominal keystone angle of 1.0 degrees, width of 10.05 mm and mid-thickness of 1.26 mm. Cable for the first set of TQ mag- nets will be made from MJR strand that is currently available in quantities sufficient for two short models. Subsequent magnets will use RRP strand currently under development with higher [3]. TQC01 specifications are shown in Table I. B. Structure The TQC mechanical structure is shown in Fig. 2. It is based on the structure of the MQXB quadrupoles built at Fermilab for the LHC interaction region [4]. MQXB collars are used, with inner layer poles removed and outer layer poles retained for coil Manuscript received September 20, 2005. This work was supported by the Di- rector, Office of Energy Research, Office of High Energy and Nuclear Physics, High Energy Physics Division, U. S. Department of Energy, under Contract DE-AC02-05CH11231. R. Bossert, G. Ambrosio, N. Andreev, E. Barzi, V. S. Kashikhin, V. V. Kashikhin, I. Novitsky, D. Turrioni, G. Whitson, R. Yamada, and A. V. Zlobin are with Fermilab National Accelerator Laboratory, Batavia, IL 60510-0500 USA (e-mail: [email protected]. S. Caspi, D. R. Dietderich, P. Ferracin, S. A. Gourlay, A. R. Hafalia, C. R. Hannaford, A. F. Lietzke, S. Mattafirri, A. D. McInturff, and G. L. Sabbi are with Lawrence Berkeley National Lab, Berkeley, CA 94720 USA. A. Ghosh is with Brookhaven National Laboratory, Upton, NY 11973 USA. Digital Object Identifier 10.1109/TASC.2006.871320