title: Field Performance of an Optimized Stack of YBCO Square "Annuli" for a Compact NMR Magnet.
abstract: The spatial field homogeneity and time stability of a trapped field generated by a stack of YBCO square plates with a center hole (square "annuli") was investigated. By optimizing stacking of magnetized square annuli, we aim to construct a compact NMR magnet. The stacked magnet consists of 750 thin YBCO plates, each 40-mm square and 80- μm thick with a 25-mm bore, and has a Ø10 mm room-temperature access for NMR measurement. To improve spatial field homogeneity of the 750-plate stack (YP750) a three-step optimization was performed: 1) statistical selection of best plates from supply plates; 2) field homogeneity measurement of multi-plate modules; and 3) optimal assembly of the modules to maximize field homogeneity. In this paper, we present analytical and experimental results of field homogeneity and temporal stability at 77 K, performed on YP750 and those of a hybrid stack, YPB750, in which two YBCO bulk annuli, each Ø46 mm and 16-mm thick with a 25-mm bore, are added to YP750, one at the top and the other at the bottom.
authors.affiliation: Francis Bitter Magnet Laboratory (FBML), Massachusetts Institute of Technology (MIT), Cambridge, MA 02139 USA.
authors.forename: Seungyong
authors.initials: S
authors.lastname: Hahn
authors.forename: John
authors.initials: J
authors.lastname: Voccio
authors.forename: Stéphane
authors.initials: S
authors.lastname: Bermond
authors.forename: Dong-Keun
authors.initials: DK
authors.lastname: Park
authors.forename: Juan
authors.initials: J
authors.lastname: Bascuñán
authors.forename: Seok-Beom
authors.initials: SB
authors.lastname: Kim
authors.forename: Tomita
authors.initials: T
authors.lastname: Masaru
authors.forename: Yukikazu
authors.initials: Y
authors.lastname: Iwasa
references.citation: IEEE Trans Appl Supercond. 2010 Jun 1;20(3):1037-1040
references.pmid: 20585463
references.citation: IEEE Trans Appl Supercond. 2010 Jun;20(3):718-721
references.pmid: 33132668