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

Self Cite

Abstract-A key issue in the construction of the MICE cooling channel is the magnetic forces between various elements in the cooling channel and the detector magnets. This report describes how the MICE cooling channel magnets are hooked to together so that the longitudinal magnetic forces within the cooling channel can be effectively connected to the base of the experiment. This report presents a magnetic force and stress analysis for the MICE cooling channel magnets, even when longitudinal magnetic forces as large as 700 kN (70 tons) are applied to the vacuum vessel of various magnets within the MICE channel. This report also shows that the detector magnets can be effectively separated from the central MICE cooling channel magnets without damage to either type of magnet component.

Section: The Magnetic Coupling Of the Mice Coilsmentioning

confidence: 99%

“…The coupling between the various magnet circuits manifests itself in how the magnets are affected during a quench and the fact the quenching of one group of magnets in MICE will cause adjacent magnets to quench [6].…”

Section: The Magnetic Coupling Of the Mice Coilsmentioning

confidence: 99%

The Physical Connection and Magnetic Coupling of the MICE Cooling Channel Magnets and the Magnet Forces for Various MICE Operating Modes

Yang

Baynham

Fabricatore³

et al. 2007

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“…The relevant physical parameters of the five coils are given in Table I [3], [4]. The magnet and its shields are cooled by five two-stage 4.2 K coolers [5], [6]. The electrical diagram for the magnet is shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

Unbalanced Quenching in a Long Solenoid With Separately Powered Coils

Green

Pan

Prestemon

et al. 2014

Self Cite

Abstract-Quenches were simulated for a long solenoid composed of five separately powered coils. Two coils, at one end of the magnet, are separately powered by 300-A power supplies, so that the uniform field section of the magnet is matched to the rest of a physics experiment. The three coils in the uniform field end are connected in series and are powered by a single 300-A power supply. The two end coils of the three-coil set use separate 60-A power supplies to trim the uniform field. Quench back from the 6061-Al mandrel is an important part of the quench protection for the three-coil section. Quench propagation from one separately powered coil to the next was simulated by using the Opera3D program of the Vector Fields. Low current quench simulations showed that some coils carry currents for a long time before quenching. Since the magnet doesn't quench all at once, there can be unbalanced forces developed in the coils and the thermal shield.

“…It is particularly effective in a situation where the normal zone hits boundaries early in the quench process and thereafter spreads very slowly in the other dimensions [3][4][5]. When magnets are connected in series, quench-back can potentially cause the other magnets to quench even if they are not inductively coupled [6] [7].…”

Section: Introductionmentioning

confidence: 99%

The Role of Quench-Back in the Passive Quench Protection of Uncoupled Solenoids in Series With and Without Coil Sub-Division

Guo

Green

Wang

et al. 2011

Abstract-This paper is the final paper in a series of papers that discusses passive quench protection for high inductance solenoid magnets [1], [2]. This report describes how passive quench protection system may be applied to superconducting magnets that are connected in series but not inductively coupled. Previous papers have discussed the role of magnet sub-division and quench back from a conductive mandrel in reducing the hot-spot temperature and the peak coil voltages to ground. When magnets are connected in series, quench-back from a conductive mandrel can cause other magnets in a string to quench even without inductive coupling between magnets. The magnet mandrels must be well coupled to the magnet circuit that is being quenched. When magnet circuit sub-division is employed to reduce the voltages-to-ground within magnets, the resistance across the subdivision becomes the most important factor in the successful quenching of the magnet string.Index Terms-Quench-back, Sub-division quench protection