Performance Test of a G-M Cooler in Magnetic Field

Kostrov, E. A.; Bagdinov, A. V.; Демихов, Е. И.; Demikhov, T. E.; Лысенко, В. В.; Piskunov, Nikolay

doi:10.1016/j.phpro.2015.06.055

Cited by 13 publications

(5 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The fields around the 1st stage and the 2nd stage are both less than 0.5 T, which is also acceptable for normal operation of the cryocooler according to [50].…”

Section: Cold Head Position and Its Shielding From The Fieldmentioning

confidence: 91%

“…Another special issue is about the cold head position with respect to the magnetic field distribution for the passively shielded magnet. The accepted field on the motor part of the cryocooler is at most 0.03 T in every direction [50]. But it is also preferred that the cold head is as close as possible to the HTS coils for short cooling path.…”

Section: Cold Head Position and Its Shielding From The Fieldmentioning

confidence: 99%

See 1 more Smart Citation

Key designs of a short-bore and cryogen-free high temperature superconducting magnet system for 14 T whole-body MRI

Roell

2021

Supercond. Sci. Technol.

View full text Add to dashboard Cite

A 14 T whole-body magnetic resonance imaging (MRI) magnet is designed with Bi2223 high temperature superconducting (HTS) wire. Owing to the large critical current and large critical tensile strength of the wire type HT-NX at ultra-high field, the magnet is optimized in a compact shape with length of 1.9 m and outer diameter of 1.3 m. It is in the form of stacked double pancakes (DPs) with total wire consumption of 455 km. The DPs with various inner and outer radii enable the electromagnetic design to obtain highly homogeneous field of 1.5 ppm over 400 mm diameter of spherical volume (DSV). Hoopstress by winding process, thermal contraction and Lorenz force is calculated and below the wire strength specification. Considerable reduction of screening current effect in MRI magnet application is proved by a calculation example. Field homogeneity as it is influenced by various systematic tolerances and random geometric tolerances is numerically estimated, for further design optimization and design of shimming system. Iron room for passive shielding with dimension of 5 × 5 × 10 m is found to be with wall thickness of around 30 cm to effectively contain the 5-Gauss field to the wall surface. Cooling strategy for cryogen-free technique is proposed and the magnet coils temperature is calculated as below 8 K based on the estimation of joint Ohmic heating power of 1.0 W. Quench protection adopts circuit subdivision and dumping resistors to restrict the maximum voltage below 1.9 kV. No-insulation technique for the quench protection is also discussed. Some other wire candidates like REBCO and Nb3Sn for development of such ultra-high field MRI magnets are commented.

show abstract

“…The fields around the 1st stage and the 2nd stage are both less than 0.5 T, which is also acceptable for normal operation of the cryocooler according to [50].…”

Section: Cold Head Position and Its Shielding From The Fieldmentioning

confidence: 91%

Section: Cold Head Position and Its Shielding From The Fieldmentioning

confidence: 99%

Key designs of a short-bore and cryogen-free high temperature superconducting magnet system for 14 T whole-body MRI

Roell

2021

Supercond. Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…Layer thickness (mm) region, in this design below 100 mT [20]. The main chamber is made of AISI 304 stainless steel.…”

Section: Componentmentioning

confidence: 99%

Mechanical design of a superconducting demonstrator for magnetic density separation

Kosse

Wessel

Zhou

et al. 2021

Supercond. Sci. Technol.

View full text Add to dashboard Cite

The focus of this paper is on the mechanical design of a NbTi-based demonstrator magnet for magnetic density separation (MDS) that is being constructed at the University of Twente. MDS is a new recycling technology that allows the separation of non-magnetic particles based on their mass density, using a vertical magnetic field gradient and a ferrofluid. The unique mechanical design challenge for this type of magnet is the desired minimization of the distance between a sim1 m2 planar array of cryogenic racetrack coils and the ambient-temperature ferrofluid bath. The optimization of the magnet geometry results in a distance between the coils and ferrofluid of 50 mm. This is made possible by opting for conduction-cooling, for the inclusion of room-temperature rods that pass through the cold mass to support the cryostat, and for the geometry of the cassette that reacts to the Lorentz force.

show abstract

“…In the conduction-cooled superconducting magnet system, the cryocooler instead of liquid helium or nitrogen is used as the heat sink. Since the stray magnetic field will degrade the cooling capacity of the cryocooler [7,8], the cryocooler should be away from the superconducting magnet, and the flexible copper strap is usually used as the thermal link between the second stage of cryocooler and the superconducting magnet. The superconducting magnet must be cooled from room temperature to the operating temperature before starting, and it will take several hours or even ten days [9][10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Optimization of thermal link for a conduction-cooled superconducting magnet system

Liang,

Fang,

Han

et al. 2023

J. Inst.

View full text Add to dashboard Cite

The thermal link between the second stage of cryocooler and the superconducting magnet has a significant influence on the initial cooldown time of conduction-cooled superconducting magnet. In this paper, a numerical investigation is carried out on the initial cooldown characteristics of a superconducting magnet system used flexible copper strap as the thermal link. The optimal shape ratio (cross-sectional area to length) of the copper strap is obtained to minimize the cooldown time. The results show that optimal shape ratio decreases with increasing the length. In addition, the effect of copper purity on the cooldown time is little at the optimal shape ratio or at RRR (Residual Resistive Ratio) > 100.

show abstract

Performance Test of a G-M Cooler in Magnetic Field

Cited by 13 publications

References 4 publications

Key designs of a short-bore and cryogen-free high temperature superconducting magnet system for 14 T whole-body MRI

Key designs of a short-bore and cryogen-free high temperature superconducting magnet system for 14 T whole-body MRI

Mechanical design of a superconducting demonstrator for magnetic density separation

Optimization of thermal link for a conduction-cooled superconducting magnet system

Contact Info

Product

Resources

About