The Dimensions and Number of Turns for the Tracker Solenoids As-Built compared to the Original Magnet Design

摘要

The two tracker solenoids for MICE [1]-[3] as-built are different from the original design proposed by Wang NMR [4]. The Wang NMR design is in turn different from the magnet design proposed in the original MICE tracker magnet specification [5]. The two tracker solenoids where fabricated with niobium titanium conductor supplied to LBNL by Luvata under a specification written by LBNL [6]. This report compares the as-built tracker solenoids to the original Wang NMR design [4]. The as-built solenoid coils are thicker by 5 to 8 percent than called for the original design. This means that the current center is moved outward from 0.2 to 0.5 percent. In both tracker magnets, the thickness of end coil 2 was increased by 2-layers over the original design [5]. Thus, the current center for end coil 2 was moved outward by 0.7 percent. The number of turns per layer was underestimated in the original design from 2 to 4 percent. As a result, the current in each of the five tracker solenoid coils must be increased. In turn, the two as built tracker solenoids are compared to each other. In the ways that matter, the two tracker solenoids are nearly identical to each other. The largest difference between the two magnets that matters is a 0.05 percent change in the current in the center coil of the three coil set that forms the spectrometer solenoid. Since this is the largest variation that matters, it can be concluded that coils M1, coils M2, and the spectrometer solenoid can be connected in series without affecting the beam dynamics of MICE. This includes the two tuned end coils as well. The position of the coils within the cryostats vacuum vessel appears to be acceptable.