title: T1-weighting of Hahn echo-trains in the stray-field for deuterium: prospects for imaging using long echo-train summation.
abstract: Hahn-echoes have been observed in stray-field gradients of 37.5 T/m and 74.5 T/m for deuterium in heavy water in a number of forms: liquid, ice, and coordinated in solid copper sulfate and silica gel. In the diamagnetic samples, the application of many pulses (> 1000 or more) in long pulse-trains produced many sustained echoes. This lengthening of T(echo) is caused by T1-weighting of the components of the Hahn echo (even in the absence of spin-locking). In contrast, for the paramagnetic complex, the shortening of T1 greatly reduces T(echo) and only few echoes are obtained. A new protocol for stray field imaging is suggested when T1 is long: long echo-train summation (LETS). The observed magnetisation is much greater for heavy ice than for heavy water because the line-width, and hence the thickness of the excited slice, is greater.
authors.affiliation: ICTPOL/IST, Departamento de Engenharia de Materiais, Lisboa, Portugal.
authors.forename: E W
authors.initials: EW
authors.lastname: Randall
authors.forename: T G
authors.initials: TG
authors.lastname: Nunes
authors.forename: G
authors.initials: G
authors.lastname: Guillot
authors.forename: P R
authors.initials: PR
authors.lastname: Bodart
mesh_terms: D019327:Copper Sulfate / Q000032:analysis; D003903:Deuterium / Q000032:analysis*; D004578:Electron Spin Resonance Spectroscopy; D005782:Gels; D012822:Silicon Dioxide / Q000032:analysis
chemical_list: D005782:Gels; D012822:Silicon Dioxide; D003903:Deuterium; D019327:Copper Sulfate