A convenient method for calibration of the pulse-length in high field-gradients using Hahn echo-trains

✍ Scribed by Edward W Randall

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 83 KB
• Volume: 8
• Category: Article
• ISSN: 0926-2040
• DOI: 10.1016/s0926-2040(97)00002-7

✦ Synopsis

A new method is presented for calibration of the pulse-length in the case that the sample, which can be either a liquid or a solid, is placed in a high field-gradient such as it experiences in the stray-, fringe-field of a solenoid. The method employs Ž . a pulse-train, with a constant phase, of the form a -t-a -t-echo-t-. This produces Hahn echoes which have variable X

X n Ž phase in the form of phase-alternations along the echo-train. For a s 908 the relative phase-sequence in degrees is 0, 0, 180, . 180 , and we may characterise this by m s 2, since there are two signals of one phase in each group. For other cases with Ž . these phase angles 0 and 180 but different numbers, m, of signals with opposite phase, we have a s 180rm, where m is an integer. q 1997 Elsevier Science B.V.