Profiles of paint layer samples obtained in the fringe field of a high field magnet by means of very short broadband frequency-modulated pulses

Profiles of paint layer samples obtained in the fringe field of a high field magnet by means of very short broadband frequency-modulated pulses

© 2020 John Wiley & Sons, Ltd.

Bibliographische Detailangaben
Veröffentlicht in:Magnetic resonance in chemistry : MRC. - 1985. - 58(2020), 9 vom: 12. Sept., Seite 870-879
1. Verfasser: Taugeron, Pierre (VerfasserIn)
Weitere Verfasser: Bricaud, Sullivan, Kehlet, Cindie, Dittmer, Jens
Format: Online-Aufsatz
Sprache:English
Veröffentlicht: 2020
Zugriff auf das übergeordnete Werk:Magnetic resonance in chemistry : MRC
Schlagworte:Journal Article 1H NMR depth profiles frequency-modulated pulses paint
Beschreibung
Zusammenfassung:© 2020 John Wiley & Sons, Ltd.
In this article, we describe the acquisition of depth profiles, in particular of paint layers, in the static gradient of a high field magnet, providing a superior sensitivity. The main objective are reference profiles that help to understand scans made with noninvasive unilateral nuclear magnetic resonance (NMR), which often suffers from poor signal-to-noise ratio when working with real samples. Various technical aspects like the coil geometry and the limit of resolution are investigated. A major advancement is the use of frequency-modulated pulses that are very broadband and at the same time very short (25 μs). The latter is necessary to allow the acquisition of a CPMG echo train of old, rigid paint material. Despite being far from adiabatic, they provide uniform excitation and refocusing over 1 MHz, which corresponds to about 400 μm with the used gradient. We show that the uniformity is even sufficient to obtain biexponential relaxation profiles. With these tools, a paint sample from a restoration campaign is analyzed with different contrast criteria: The original and two layers from former restoration attempts can be visualized, and furthermore, the relaxation profiles allow to study the migration of plasticizing molecules
Beschreibung:Date Revised 07.12.2020
published: Print-Electronic
Citation Status PubMed-not-MEDLINE
ISSN:1097-458X
DOI:10.1002/mrc.5038