Progress on the Coupling Coil for the Mice Channel

Abstract

This report describes the progress on the coupling magnet for the international Muon Ionization Cooling Experiment (MICE). MICE consists of two cells of a SFOFO cooling channel that is similar to that studied in the level 2 study of a neutrino factory. The MICE RF coupling coil module (RFCC module) consists of a 1.56 m diameter superconducting solenoid, mounted around four cells of conventional 201.25 MHz closed RF cavities. This report discusses the progress that has been made on the superconducting coupling coil that is around the center of the RF coupling module. This report describes the process by which one would cool the coupling coil using a single small 4 K cooler. In addition, the coupling magnet power system and quench protection system are also described.

The Inductive Coupling of the Magnets in MICE and its Effect on Quench Protection

“…At the end of the quench the mandrel temperature is a lot cooler than the average coil temperature (52 K versus 82 K). Similar quench studies were done on the coupling magnet (see Table 3) [7], [9]. Figure 3 shows the current decay of the coupling magnet and the coil hot-spot temperature as a function of the time from the quench start.…”

“…The quench-back time is short (~1.1 s) so the energy is more evenly spread between magnets. Thus connecting the three focusing magnets together in series appears to be attractive [7], [8]. At the end of the quench the mandrel temperature is a lot cooler than the average coil temperature (52 K versus 82 K).…”

The Cold Mass Support System and the Helium Cooling System for the MICE Focusing Solenoid

“…3 The focusing magnet is designed to operate in both the gradient mode (flip mode) with the two coils operating at opposite polarity or the solenoid mode (non-flip mode) where the coils operate at the same polarity [4]. The forces and fields at the conductor are much higher when the focusing magnet operates in the flip mode [5]. Table 1 shows the parameters for the MICE focusing magnets while they operate in either mode at the highest muon momentum (240 MeV/c).…”

Progress on the design of the coupling coils for mice and mucool

“…The design limits on the MICE coupling magnets come from the vacuum vessel that surrounds the four RF cavities and the distance between the 201.25-MHz RF cavity couplers [2], [3]. The RF cavities that are used to accelerate muons after they have been cooled using ionization cooling determine the design of the MICE coupling magnet.…”