GALEN W. EWING Seton Hall University
S O W Orange. New Jersey 07079
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XCV. A Simple Super-Regenerative Nuclear Quadrupole Spectrometer Employing Self-Quench Frequency Change to Detect Resonance Frequencies
Transitions between energy levels may occur when an oscillating magnetic field is applied. This field interacts with the magnetic dipole moment of the nucleus, p, causing a time dependent perturbation with time dependent Hamiltonian
H ( ~=) - r h [ H A t ) L +H&)I,
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where H , @ ) , H&), and H , @ ) are the components of the polarized radio frequency (rf) field. The rf field may be described by
R. J. Trepanier, M. A. Whitehead and E. P. A. Sullivan McGill University, Montreal, Quebec, Canada H3A 2K6
H = 2H1 cos w,t
p=rP
A simple self-quenching super-regenerative nuclear quadrupole resonance (NQR) spectrometer is described in this article. At resonance the quench frequency (the number of radio frequency pulses per see) increases. This increase in quench frequency is ohserved using an inductive loop placed near the tank circuit which feeds the radio frequency (10 pulses to an oscilloscope, or by using a ratemeter and recorder. Also, at resonance, the plate current alters in the triode oscillator. This latter effect is observed by to the spectrometer adding a low and displaying the resultingsignal on an 0scilloseape or a recorder and is the usual basis for N.Q.R. frequency detection. The solid samples of Na3%103, 1,4-35C1&~H4, and W u 2 0 were studied at room temperature. They gave resonance frequencies of 29.904 f 0.003 MHz,34.256 f 0.007 MHz and 20.024 f 0.002 MHz respectively.
Nuclei with I t 1have a non-spherical nuclear charge distribution and an electric quadrupole moment, Q. For simplicity the electric field will be assumed axially symmetric. The Hamiltonian for the interaction of the nuclear quadrupole moment, has been discussed by Cohen and Reif ( I ) . A suhsew e n t derivation by Das and Hahn ( 2 ) gave
