- AutorIn
- Denise E. Freed
- Ulrich M. Scheven
- Martin D. Hürlimann
- Titel
- Split 180° sequences
- Zitierfähige Url:
- https://nbn-resolving.org/urn:nbn:de:bsz:15-qucosa-192244
- Quellenangabe
- Diffusion fundamentals - 10
- Quellenangabe
- Diffusion fundamentals 10 (2009) 19, S. 1-3
- Erstveröffentlichung
- 2009
- Abstract (EN)
- In applications of NMR in inhomogeneous fields, sequences based on the Carr-Purcell-Meiboom-Gill (CPMG) sequence play a central role. The standard CPMG sequence consists of an initial 90° excitation pulse, followed by a long string of 180° refocusing pulses. This creates a series of echoes that decay with characteristic relaxation time T2eff. Here we present a modified sequence, the Split-180° sequence that specifically takes advantage of grossly inhomogeneous fields. In its simplest implementation, the 180° refocusing pulse of the CPMG sequence is split into two separate pulses. This sequence, which can be viewed as a modification of the CPMG sequence, simultaneously generates two types of signal that can be separately detected. One is a CPMG-like signal that decays with the expected relaxation time T2eff. In addition, a second type of signal builds up and approaches a steady-state. The amplitude of this dynamic equilibrium depends on the ratio of the longitudinal to the transverse relaxation times, T1/T2. We present experimental results and summarize the new theory that describes both signals in a unified manner.
- Freie Schlagwörter (DE)
- Diffusion, Transport
- Freie Schlagwörter (EN)
- diffusion, transport
- Klassifikation (DDC)
- 530
- Herausgeber (Institution)
- Schlumberger-Doll Research
- FCT Universidade Nova de Lisboa
- Universität Leipzig
- URN Qucosa
- urn:nbn:de:bsz:15-qucosa-192244
- Veröffentlichungsdatum Qucosa
- 17.12.2015
- Dokumenttyp
- Artikel
- Sprache des Dokumentes
- Englisch