Accession Number : ADA115203

Title :   Nuclear Moment Alignment, Relaxation and Detection Mechanisms.

Descriptive Note : Final rept. Feb 77-Jan 82,


Personal Author(s) : Nicol,A T

PDF Url : ADA115203

Report Date : Feb 1982

Pagination or Media Count : 116

Abstract : The reported physics research is part of an overall program to develop a nuclear magnetic resonance gyro that makes use of an optically pumped alkali metal vapor both to align the magnetic moments of the noble gas nuclei and to detect the weak magnetic fields that are generated by these precessing nuclear moments. Experiments designed to hold constant the rubidium vapor density in an NMR sample cell and thus restrict the spin exchange interaction while varying the cell wall temperature are reported. These experiments lead to longer relaxation times and larger signal amplitudes for the noble gas isotopes at elevated wall temperatures than is observed in the case where alkali metal vapor density is not restricted. (129)Xe magnetic resonance frequency shift experiments are reported in which the transverse relaxation times are found to depend strongly on choice of polarizer, pump light intensity, and alkali vapor density. The results are explained in terms of internally generated field gradients due to spacially non-uniform rubidium polarization across the sample cell. An analytical discussion of the temperature sensitivity of the NMR gyro bias due to quadrupolar frequency shift in (131)Xe is presented. That frequence shift is demonstrated to be a mechanism for the temperature dependence of the gyro bias and the temperature turning point (temperature at which temperature sensitivity of gyro bias becomes zero). Studies of Corning 1720 glass NMR cells, both rubidium hydride coated and non coated, are presented and compared with results for similarly prepared Pyrex cells. Hydride coated cells of both types are found to exhibit similar properties.

Descriptors :   *Gyroscopes, *Nuclear magnetic resonance, *Nuclear moments, *Optical pumping, Alignment, Alkali metals, Vapors, Density, Detectors, Research management, Magnetic moments, Gradients, Field conditions, Rare gases, Magnetic fields, Inertial navigation, Heat resistant glass, Polarization, Isotopes, Hydrides, Rubidium, Amplitude, Relaxation

Subject Categories : Physical Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE