STUDY OF NUCLEAR PHYSICS USING BRUTE FORCE LOW-TEMPERATURE NUCLEAR POLARIZATION

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Brute-force NMR-ON (BF-NMRON) is an attractive method for measuring g-factors without the knowledge of hyperfine interaction and hyperfine anomaly. The samples of ィイD175ィエD1SeFe, ィイD190ィエD1NbCu, ィイD190ィエD1NbNb, ィイD196ィエD1TcNb and ィイD1101mィエD1RhCu were prepared by recoil implantation into host metals (2μm) using 50MeV and 75MeV alpha- beams. Cooling down of the sample to low temperature about 10 mK was performed with a ィイD13ィエD1He/ィイD14ィエD1H dilution refrigerator. The vertical polarization field was provided by an NbィイD23ィエD2Sn superconducting solenoid with 12T maximum field at 4.2K. The manufacturer's computed homogeneity is 5x10ィイD1-4ィエD1 in 1 cm d.s.v. The hyperfine field of ィイD175ィエD1SeFe was determined to be 67.9(7)T by measuring the resonances at the external magnetic field of 0.2, 2 and 6T.We have succeeded in measuring BF-NMRON for ィイD190ィエD1NbCu, ィイD190ィエD1NbNb, ィイD196ィエD1TcNb and ィイD1101mィエD1RhCu. The resonance frequencies of ィイD190ィエD1NbCu and ィイD190ィエD1NbNb at 12T are 56.448(2) MHz and 56.57(1) MHz, respectively. The resonance widths are 21(1) kHz and 49(3) kHz. The resonance frequency of ィイD1101mィエD1RhCu at 12T is 110.8775(3) MHz. The width is 17(1) kHz. The relaxation time was also measured. To measure the absolute value of the magnetic field and the linearity of the field strength vs. the electric current the resonances of the well-known ィイD1110mィエD1AgAg made by a reactor were measured at various external field between 12T and 2T. The resonance width at 12T is 26(2) kHz. With the known magnetic moments and the field correction the Knight shifts of ィイD190ィエD1NbCu, ィイD190ィエD1NbNb, ィイD196ィエD1TcNb and ィイD1101mィエD1RhCu were determined.