Patent ID: 6525535
Filing Date: 2003-02-25
Classification: G01N,G01V

Abstract:
A Nuclear Magnetic Resonance (NMR) apparatus comprising:(a) a permanent magnet assembly for producing a static magnetic field in a region of examination; (b) a primary antenna for generating a first RF magnetic field in a region of examination, said first RF field having a direction substantially perpendicular to a direction of the static field in said region; (c) a secondary antenna generating a second PF magnetic field having a direction substantially perpendicular to the static field in said region, said secondary antenna adaptable to operate in a mode selected from the group consisting of (i) a spoiler mode wherein said second RF field has a substantial component anti-parallel to said first RF field in a specified region, and, (ii) a booster mode wherein said second RF field has a substantial component parallel to said first RF field in a specified region; wherein said spoiler mode is used when the apparatus is used in a large borehole and said booster mode is used when the apparatus is used in a small borehole.