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Author TonThat, D. M. ♦ Clarke, J.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword INSTRUMENTATION, INCLUDING NUCLEAR AND PARTICLE DETECTORS ♦ MAGNETIC SPECTROMETERS ♦ SQUID DEVICES ♦ NUCLEAR MAGNETIC RESONANCE ♦ NUCLEAR QUADRUPOLE RESONANCE ♦ ELECTRONIC CIRCUITS ♦ MHZ RANGE 01-100 ♦ ALUMINIUM 27 ♦ RUBY
Abstract A spectrometer based on a dc superconducting quantum interference device (SQUID) has been developed for the direct detection of nuclear magnetic resonance (NMR) or nuclear quadrupole resonance (NQR) at frequencies up to 5 MHz. The sample is coupled to the input coil of the niobium-based SQUID via a nonresonant superconducting circuit. The flux locked loop involves the direct offset integration technique with additional positive feedback in which the output of the SQUID is coupled directly to a low-noise preamplifier. Precession of the nuclear quadrupole spins is induced by a magnetic field pulse with the feedback circuit disabled; subsequently, flux locked operation is restored and the SQUID amplifies the signal produced by the nuclear free induction signal. The spectrometer has been used to detect {sup 27}Al NQR signals in ruby (Al{sub 2}O{sub 3}[Cr{sup 3+}]) at 359 and 714 kHz. {copyright} {ital 1996 American Institute of Physics.}
ISSN 00346748
Educational Use Research
Learning Resource Type Article
Publisher Date 1996-08-01
Publisher Department Lawrence Berkeley National Laboratory
Publisher Place United States
Journal Review of Scientific Instruments
Volume Number 67
Issue Number 8
Organization Lawrence Berkeley National Laboratory


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