Gyromagnetic ratios of the 4+ and 6+ rotational states of184W

Abstract

The nuclear Larmor precession has been observed for the 2 +, 4 + and 6 + rotational states of ls4W in the hyperfine field of WFge by application of the TDPAC and the IPAC techniques. A carrier free radioactive source of lS4mRe alloyed with high purity iron was used for all three measurements. (5) with the sign convention of Krane and Steffen.

Gyromagnetic ratio of the 2+ rotational state of184W and observation of a large hyperfine anomaly with respect to183Wg in iron

“…The measured time spectrum looks very similar to that shown in Fig. 3 of [1], but the statistical accuracy was improved. For a precise time calibration we applied the following technique: We mounted the detectors at a distance of 2 m and observed for a 22Na source the shift of the coincidence peak of the annihilation quanta in the time spectrum when the source was moved along the line between the detectors.…”

“…This so-called "after effect" is not expected for metallic environments since the atomic shells recover there much faster because of the availability of very mobile conduction electrons. The decays of 18~Re and 184"Re offer a unique opportunity to further investigate this question by making use of the 8.3 ~ts isomeric level of a84W at 1285keV, see decay scheme of 184mRe in [1]. If the described EC-"after effect" would be responsible for the fast component of the observed attenuation the effect should disappear for any other y-y cascade with the same intermediate state, however being fed by the 8.3 ~ts level.…”

“…By inserting for the g-factor of the 2 + state the average value of the most reliable data published for IPAC and integral perturbed angular distribution (IPAD) measurements with external magnetic fields we obtained a hyperfine field for ~84W2+ F e* which was by more than 10% larger than that known from spin echo experiments with 18aWgF__ee [2]. As was mentioned in [1] this difference may be explained by the Bohr-Weisskopf effect [-3J although it is astonishingly large. Since the weakest point in the derivation is the absolute value of the g-factor of the 2 + state, we found it worthwhile to remeasure this g-factor with high accuracy by use of our 10T superconducting magnet.…”

“…(2) Another fraction was dissolved in boiling H20 2 (30%) and the 18~Re activity was separated carrierfree by an ion exchange procedure described in detail in [1]. The activity was evaporated to dryness and taken up in a few drops of 2M H2SO 4 and was used in this form as liquid source; it is then essentially in the chemical form of [ReO4J-ions.…”

“…In our recent investigation of the magnetic moment of the 4 + and 6 + states of lS4W by use of the integral perturbed angular correlation (IPAC) method [1] we calibrated the hyperfine field of the ~84ReF__~e sample by observing the spin rotation in the 2 + states by a time differential measurement. By inserting for the g-factor of the 2 + state the average value of the most reliable data published for IPAC and integral perturbed angular distribution (IPAD) measurements with external magnetic fields we obtained a hyperfine field for ~84W2+ F e* which was by more than 10% larger than that known from spin echo experiments with 18aWgF__ee [2].…”