{"title":"Two-pulse frequency-hopped excitation","authors":"Carl A. Michal, Ronald Y. Dong","doi":"10.1002/cmr.a.21416","DOIUrl":null,"url":null,"abstract":"<p>The use of frequency-hopped pulse pairs and pulse pair trains for exciting NMR signals is introduced. Pairs of pulses, each pair lasting one nutation period about the effective field in the rotating frame, can be used to efficiently tip nuclear spin magnetization. In the limit where the frequency difference between the partners in a pair is large, the magnetization dynamics mimic those of an ordinary rectangular rf pulse with rf amplitude scaled down by a factor of π/2. When the amplitude of the applied rf begins to approach the offset frequency however, the excitation bandwidth broadens dramatically in a manner reminiscent of a composite pulse. The effects of the frequency-hopped pulse pairs is described with analytical calculations and numerical simulations, and are shown to agree well with experiment.</p>","PeriodicalId":55216,"journal":{"name":"Concepts in Magnetic Resonance Part A","volume":"45A 6","pages":""},"PeriodicalIF":0.4000,"publicationDate":"2018-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/cmr.a.21416","citationCount":"2","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Concepts in Magnetic Resonance Part A","FirstCategoryId":"92","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1002/cmr.a.21416","RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
引用次数: 2
Abstract
The use of frequency-hopped pulse pairs and pulse pair trains for exciting NMR signals is introduced. Pairs of pulses, each pair lasting one nutation period about the effective field in the rotating frame, can be used to efficiently tip nuclear spin magnetization. In the limit where the frequency difference between the partners in a pair is large, the magnetization dynamics mimic those of an ordinary rectangular rf pulse with rf amplitude scaled down by a factor of π/2. When the amplitude of the applied rf begins to approach the offset frequency however, the excitation bandwidth broadens dramatically in a manner reminiscent of a composite pulse. The effects of the frequency-hopped pulse pairs is described with analytical calculations and numerical simulations, and are shown to agree well with experiment.
期刊介绍：
Concepts in Magnetic Resonance Part A brings together clinicians, chemists, and physicists involved in the application of magnetic resonance techniques. The journal welcomes contributions predominantly from the fields of magnetic resonance imaging (MRI), nuclear magnetic resonance (NMR), and electron paramagnetic resonance (EPR), but also encourages submissions relating to less common magnetic resonance imaging and analytical methods.
Contributors come from academic, governmental, and clinical communities, to disseminate the latest important experimental results from medical, non-medical, and analytical magnetic resonance methods, as well as related computational and theoretical advances.
Subject areas include (but are by no means limited to):
-Fundamental advances in the understanding of magnetic resonance
-Experimental results from magnetic resonance imaging (including MRI and its specialized applications)
-Experimental results from magnetic resonance spectroscopy (including NMR, EPR, and their specialized applications)
-Computational and theoretical support and prediction for experimental results
-Focused reviews providing commentary and discussion on recent results and developments in topical areas of investigation
-Reviews of magnetic resonance approaches with a tutorial or educational approach
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