A METHOD AND APPARATUS FOR DETECTING A SUBSTANCE USING NUCLEAR RESONANCE

A METHOD AND APPARATUS FOR DETECTING A SUBSTANCE USING NUCLEAR RESONANCE

A method and apparatus for detecting a prescribed substance in a specimen, using nuclear quadrupole resonance or nuclear magnetic resonance. The nuclei of the specimen are irradiated with a modified steady state free precession RF pulse sequence comprising a plurality of pulses. The pulse sequence i...

Ausführliche Beschreibung

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Bibliographische Detailangaben
Hauptverfasser: RUDAKOV, TARAS, NIKOLAEVITCH, BELIAKOV, ALEXANDRE, VLADISLAVOVITCH, CHISHOLM, WARRICK, PAUL, MIKHALTSEVITCH, VASSILI, TIMOFEEVITCH
Format: Patent
Sprache:eng ; fre
Schlagworte:
MEASURING
MEASURING ELECTRIC VARIABLES
MEASURING MAGNETIC VARIABLES
PHYSICS
TESTING
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Beschreibung
Zusammenfassung:A method and apparatus for detecting a prescribed substance in a specimen, using nuclear quadrupole resonance or nuclear magnetic resonance. The nuclei of the specimen are irradiated with a modified steady state free precession RF pulse sequence comprising a plurality of pulses. The pulse sequence includes pairs of pulses offset from each other by a prescribed phase shift to produce a plurality of nuclear resonance echo signals from the prescribed substance, if present. The pulse sequence is constructed with pairs of pulses where phases of adjacent pulse pairs are offset by 90 DEG of the type: [ tau /2 - ( theta - DELTA tau - theta )>0< DEG - tau - ( theta - DELTA tau - theta )>90 DEG < - tau /2]>n0 DEG < - tau - ( theta - DELTA tau - theta )>90 DEG < -