A bulk superconducting MgB<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="mml7" display="inline" overflow="scroll" altimg="si1.gif"><mml:msub><mml:mrow/><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:math> cylinder for holding transversely polarized targets

Statera, M.; Balossino, I.; Barion, L.; Ciullo, G.; Contalbrigo, M.; Lenisa, P.; Lowry, M.; Sandorfi, A. M.; Tagliente, G.

doi:10.1016/j.nima.2017.10.051

Cited by 13 publications

(7 citation statements)

References 10 publications

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“…Passive magnetic shields and cloaks operating at high applied magnetic fields are particularly suited for applications involving particle beams [17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Anisotropy of the thermal conductivity of bulk melt-cast Bi-2212 superconducting tubes

Szewczyk¹,

Stachowiak²,

Mucha³

et al. 2020

Supercond. Sci. Technol.

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We investigate experimentally the anisotropy of the temperature dependence of the thermal conductivity of bulk Bi2Sr2CaCu2O8 (Bi-2212) cylinders fabricated by the melt-cast process. The thermal conductivity κ(T) along the axial and azimuthal directions are found to be equal within experimental uncertainty, while κ along the radial direction is found to be ~ 40% larger than the other two. The results are in qualitative agreement with the weak partial texture of such tubes, corresponding also to an anisotropy of the resistivity ρ(T) above the critical temperature Tc. This resistivity anisotropy in the normal state is responsible for an anisotropy of the electronic contribution of thermal conductivity (∆κe), which is much smaller than the anisotropy ∆κ of the total thermal conductivity. This indicates an anisotropic contribution of the phonons. The temperature dependence of the specific heat C(T) is also measured and shows that C(T)/T exhibits a well-defined maximum close to Tc. The combination of these experimental data can be used for assessing the thermal effects in bulk melt-cast Bi-2212, and underline the importance of taking the anisotropy of κ into account, e.g. for predicting the self-heating when the material is subjected to losses.

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“…Passive magnetic shields and cloaks operating at high applied magnetic fields are particularly suited for applications involving particle beams [17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Anisotropy of the thermal conductivity of bulk melt-cast Bi-2212 superconducting tubes

Szewczyk¹,

Stachowiak²,

Mucha³

et al. 2020

Supercond. Sci. Technol.

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“…typically 0.7 T for mumetal [13]), superconductors can be operated well above 1 tesla [14][15][16]. This feature makes superconductors the ideal materials to screen the stray field emanating from several large scale applications [17] or to create a low magnetic field region within a high external field, as may be required in particle accelerators [18][19][20]. The shielding ability is usually expressed in terms of the shielding factor (SF), i.e.…”

Section: Introductionmentioning

confidence: 99%

Magnetic shielding of various geometries of bulk semi-closed superconducting cylinders subjected to axial and transverse fields

Fagnard

Vanderheyden

Pardo

et al. 2019

Supercond. Sci. Technol.

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We consider the properties of bulk superconductors to be used as low-frequency passive magnetic shields. Although remarkable shielding properties have been recently achieved using high-temperature superconductors of various kinds, one current issue is to assemble medium-size superconducting parts to obtain large superconducting volumes. The aim of the present work is to understand how hollow, semi-closed superconductors can be combined to improve the shielding properties over sizeable volumes. In axisymmetric superconducting geometries subjected to an axial field, 2D modelling can be used to understand important features of the shielding properties. When finite-size superconductors are subjected to a transverse field, 3D modelling must be used. In this work, we use 3D finite-element modelling with an A-f formulation to investigate various geometries in which a tube is closed by a superconducting element shaped like a disk, a cup, or another cup-shaped superconductor that is coaxial with the first. The simulations help in revealing the most performant configurations to use as a function of the geometry of the applied field. Under an axial field, the type of closing is found to be irrelevant and the key ingredient to improve the shielding factor is to reduce the average field in the opening plane, e.g. by using a thicker superconductor near the open end. Under a transverse field, the difference between the shielding properties arise from the different routes taken by flux lines to penetrate the shield. In particular, the presence of flux lines channelled through the gap between a tube and a cup-shaped sample surrounding the tube are detrimental to the shielding properties. The configurations where the tube surrounds the cup-shaped sample are found to yield much higher shielding factors, whose field dependence is further improved when the tube extends slightly beyond the end of the cup. The values of the shielding factors that can be reached under a transverse field of low amplitude are discussed by comparing them to those predicted for an ideal perfectly diamagnetic superconductor of similar dimensions.

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“…We are investigating a concept to use this new target design to provide polarization transverse to the incident direction of the beam using superconducting shielding. Taking advantage of the progress of fellow Jefferson Lab scientists from the HD-Ice group, we will adapt their plan to cancel the CLAS12 solenoidal field and produce a transverse holding field with bulk, superconducting MgB 2 [27]. Our concept would polarize in CLAS12's 5 T field at 100 mbar, and transfer into the target cell, held within the MgB 2 shield.…”

Section: Transversely Polarized Targetmentioning

confidence: 99%

A Concept for Polarized $^3$He Targets for High Luminosity Scattering Experiments in High Magnetic Field Environments

Maxwell,

Milner

2021

Preprint

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We present the conceptual design of a polarized 3 He target to be used for high luminosity scattering experiments within high magnetic field environments. This two-cell target will take advantage of advancements in optical pumping techniques at high magnetic field to create 60% longitudinally polarized 3 He gas in a pumping cell within a uniform magnetic field above 1 T. By transferring the polarized gas to cryogenic target cell, the gas density is increased to create a target thickness suitable for high luminosity applications. We discuss the general design of this scheme, and plans for its application in Jefferson Lab's CLAS12 detector.

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A bulk superconducting MgB2 cylinder for holding transversely polarized targets

Cited by 13 publications

References 10 publications

Anisotropy of the thermal conductivity of bulk melt-cast Bi-2212 superconducting tubes

Anisotropy of the thermal conductivity of bulk melt-cast Bi-2212 superconducting tubes

Magnetic shielding of various geometries of bulk semi-closed superconducting cylinders subjected to axial and transverse fields

A Concept for Polarized $^3$He Targets for High Luminosity Scattering Experiments in High Magnetic Field Environments

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