The Results of Tests of the MICE Spectrometer Solenoids

Virostek, Steve; Green, M A

doi:10.1109/tasc.2010.2040603

Cited by 16 publications

(16 citation statements)

References 9 publications

(7 reference statements)

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“…The shunt resistance mass must increase with resistance in order to keep its temperature below 300 K. The three-coil spectrometer set with its four sub-divisions can quench safely by means of quench-back from the mandrel, even when the shunt resistance is very low. This has been demonstrated experimentally [8]. The diodes across the coils protected the magnet when an HTS lead burned out during the test of one of the magnet.…”

Section: The Effect Of the Shunt Resistancementioning

confidence: 88%

The Role of Quench-Back in the Passive Quench Protection of Long Solenoids With Coil Sub-Division

Guo¹,

Green

Wang

et al. 2010

IEEE Trans. Appl. Supercond.

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Abstract-This paper describes how a passive quench protection system can be applied to long superconducting solenoid magnets. When a solenoid coil is long compared to its thickness, the magnet quench process will be dominated by the time needed for quench propagation along the magnet length. Quench-back will permit a long magnet to quench more rapidly in a passive way. Quenchback from a conductive (low resistivity) mandrel is essential for spreading the quench along the length of a magnet. The mandrel must be inductively coupled to the magnet circuit that is being quenched. Current induced in the mandrel by di/dt in the magnet produces heat in the mandrel, which in turn causes the superconducting coil wound on the mandrel to quench. Sub-division is often employed to reduce the voltages to ground within the coil. This paper explores when it is possible for quench-back to be employed for passive quench protection. The role of sub-division of the coil is discussed for long magnets. Index Terms-Magnet Quench-back, Coil Sub-division. INTRODUCTION uench-back is a widely used passive quench protection method that enhances the rate of propagation of the normal zone by using a coupled secondary circuit. As quenching proceeds, the secondary will heat up. If it is in good thermal contact with the magnet winding, it will initiate further quenching-effectively increasing quench propagation velocity and therefore reducing the hot spot temperature. It is particularly effective in a situation where the normal zone hits boundaries rather early in the quenching process and thereafter spreads very slowly in the other dimension [1][2][3].Sub-division provides an alternative path for some of the current by connecting shunt resistors across sections of the magnet, and the shunt resistor can absorb some of the stored energy in the coil. So the hot spot temperature of the coil can This paper describes a passive quench protection system that may be applied to a long superconducting solenoid with sub-division. The role of quench-back in the quench protection of such a solenoid is discussed. I. PASSIVE QUENCH PROTECTION OF A LONG SOLENOID A. Long Solenoid ParametersThe solenoid discussed in this paper is a spectrometer magnet used in the MICE project, shown in Fig. 1 [5]. This magnet consists of two match coils M1 and M2 and three-coil spectrometer section (E1, C, and E2). M1 and M2 are used to match the spectrometer section with the MICE cooling channel. The three-coil section produces a uniform magnetic field (±0.3 percent) within a region that is 1000 mm long and 300 mm in diameter. The uniform field section contains a fiveplane scintillating fiber detector for muon beam emittance analysis. The magnet has an Nb-Ti superconductor with a copper to superconductor ratio of four. The insulated conductor dimensions are 1.65 by 1.00 mm. All five coils are wound on a single 6061-T6-aluminum mandrel. The cryostat consists of 4.2 K helium vessel, an 80 K thermal shield, cold mass supports for 500 kN and a 300 K vacuum vessel. The spectrometer se...

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Section: The Effect Of the Shunt Resistancementioning

confidence: 88%

The Role of Quench-Back in the Passive Quench Protection of Long Solenoids With Coil Sub-Division

Guo¹,

Green

Wang

et al. 2010

IEEE Trans. Appl. Supercond.

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“…The leads for the SuperBend magnets [3], the Venus ion source magnet [4], and the MICE spectrometer solenoids [10] were all built using same conduction cooled copper leads. These leads have a calculated IL/A of 5.2x 10 6 A m -1 at 275 A [11].…”

Section: Optimization Of the Leads From Room Temperaturementioning

confidence: 99%

Tests of copper and HTS leads with a two-stage pulse tube drop-in cooler

Green

Wang

2012

AIP Conference Proceedings

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“…While the copper leads represent over sixty percent of the heat load into the first stage, the other heal loads must not be ignored. It is extremely important that the top of the HTS leads be kept below 60 K. Failure to keep the tops of the HTS cold can cause the leads to fail [14].…”

Section: The Focusing Magnet Design Parametersmentioning

confidence: 99%

Progress on the Design and Fabrication of the MICE Focusing Magnets

Baynham

Bradshaw

Cobb

et al. 2010

IEEE Trans. Appl. Supercond.

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Abstract-The Muon Ionization Cooling Experiment (MICE) focusing solenoid magnets focus the muon beam within the MICE cooling channel on a liquid or solid absorber that is within the warm bore of solenoid. The focusing magnet has a warm bore of 470 mm. This magnet consists of two coils 210-mm long that is separated by an aluminum mandrel that is 200 mm long. Each of the coils has its own leads. The coils may be operated in either the non-flip mode (solenoid mode with both coils at the same polarity) or the flip mode (quadrupole focusing mode where both coils are at opposite polarity). This report describes the focusing solenoid magnet design that will be built by the vendor. The progress on the construction of the first of the focusing magnets will also be discussed in this report. Ultimately three of these magnets will be built. These magnets will be cooled using a pair 1.5 W (at 4.2 K) pulse tube coolers.

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The Results of Tests of the MICE Spectrometer Solenoids

Cited by 16 publications

References 9 publications

The Role of Quench-Back in the Passive Quench Protection of Long Solenoids With Coil Sub-Division

The Role of Quench-Back in the Passive Quench Protection of Long Solenoids With Coil Sub-Division

Tests of copper and HTS leads with a two-stage pulse tube drop-in cooler

Progress on the Design and Fabrication of the MICE Focusing Magnets

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