A Super Conducting 60 cm Warm Bore Cosine Theta Dipole Magnet for the Jefferson Lab Super High Momentum Spectrometer (SHMS)

Abstract

The Jefferson Lab 12 GeV upgrade involves building a new 12 GeV/c spectrometer for JLAB Hall C called the Super High Momentum Spectrometer (SHMS). This device achieves 4.5 mSr acceptance at bend angles from 5.5 degrees to 40 degrees by using five magnetic elements. The other magnetic elements of the SHMS, including the small SC dipole used to achieve the small 5.5 degree scattering angle, are described elsewhere in this conference. The 4.5 T SC dipole provides momentum analysis for particles from 1 to 12 GeV/c and has bend strength of 13.5 Tm. The magnetic design, including multipole strengths, will be presented. The dipole's cold mass uses a stainless steel shrink fit force collar, titanium keys and a copper stabilized super conductor consisting of a 36 strand surplus SSC outer cable wave soldered to a copper extruded substrate. This combination provides for a very conservative magnet that can be assembled with little or no tooling and has a high degree of stability. The force collar mechanical analysis will be presented as well as details of the magnet cryostat.