R. Eder

Nicole: New on-line orientation facility at ISOLDE/CERN

This paper presents off-line and on-line orientation results obtained with the new on line nuclear orientation device NICOLE in CERN. Magnetic moments of187,185Ptg and186Irm, electric quadrupole moment ratios between Pt isotopes with mass number 185, 187 and 189, the spin of the 2 h isomer of186Ir and a new decay scheme of184Au involving a metastable state are established. The shape variation versus mass number of the Pt isotopes leads to sign change of the spectroscopic quadrupole moment between A=187 and 185.

Measurements of spectroscopic quadrupole moments of neutron-deficient Au isotopes with quadrupole-interaction-resolved NMR-ON

Abstract We report on measurements of quadrupole-interaction-resolved nuclear magnetic resonance on oriented nuclei ( QI-NMR-ON ) of 3 2 + 193 Au (T 1 2 = 17.5 h)and 3 2 + 195 Au (T 1 2 =183 d) hcp-Co. The results for the magnetic and electric hyperfine splittings are: 193Au: νM = 67.72(2) MHz;νQ = − 15.69(4) MHz;195Au; νM = 71.65(1) MHz; νQ = − 14.34(2) MHz. Taking into account hyperfine anomalies, the magnetic moments are deduced to be: μ( 193 Au ) = 0.1396(6) μ N ; μ( 195 Au ) = 0.1487(6) μ N . With the known quadrupole moment of 193Au, Q = + 0.664(20), b, the electric field gradient of Au in hcp-Co is deduced to be eq = − 0.977(29) × 1017 V/cm2, with which Q( 195 Au ) = + 0.607(18) b is obtained for the spectroscopic quadrupole moment of 195Au. In addition, the experimentally known quadrupole splitting frequencies of 186Au, 198Au and 199Au in hcp-Co can be reinterpreted, giving the results: Q( 186 Au ) = + 3.14(16) b ; Q( 198 Au ) = + 0.640(19) b ; Q( 199 Au ) = + 0.510(16) b .

Time-resolved and time-integral on-line nuclear orientation measurements of neutron-deficient Hg−Au−Pt−Ir nuclei

The methods of time-resolved and time-integral on-line nuclear orientation have been applied to study short lived nuclei with the NICOLE facility (Nuclear Implantation into Cold On-Line Equipment) at ISOLDE-3 in CERN using beams of182–186Hg. The half-lives in these decay chains are of the order of seconds and therefore comparable to the spin-lattice relaxation times of the nuclei in iron. As the relaxation rate depends strongly on the g-factor, g-factors of nuclei in the decay chains can be deduced from the observation of the time evolution of γ-ray anisotropy. Using this technique the existence of an isomer in184Au has been found and the g-factors of184Au,184mAu and182Au have been determined. Accurate half-lives have been extracted from the data.Time-integral nuclear orientation has been observed for short lived as well as longer lived isotopes of the Hg decay chains. From these measurements, after proper correction for incomplete relaxation, the magnetic moments of183mPt,183Ir and182Ir have been derived.The applicability of the time-resolved nuclear orientation technique for nuclei far from stability and its possible limitations is discussed.

No anomaly of the magnetic moment of 174mLu

Abstract With nuclear magnetic resonance on oriented nuclei (NMR-ON) the magnetic hyperfine splitting frequency of 174m Lu (I π =6 − , T 1 2 =142 d ) in Fe was measured to be 138.5(6) MHz. With the known hyperfine field B HF (Lu Fe ) =−72.81 (36) T the magnetic moment of 174m Lu is deduced to be 1.497 (10) μN, which differs conspicuously from the previous literature value. It is discussed in the context of additivity violation of magnetic g-factors reported previously.

The hyperfine field of sodium in iron

The hyperfine field of NaFe has been measured using Low Temperature Nuclear Orientation of cold implanted24Na. The combination of both the γ-and β-anisotropies yields information on the implantation fraction of Na in Fe. Furthermore, an, upper limit for the relaxation time of Na in Fe could be deduced.