P. Raghavan

Table of nuclear moments

This table is a compilation of experimental data on static nuclear magnetic dipole ane electric quadrupole moments for ground state and excited states of nuclides from {sup 1}H to {sup 254}Es. Listed along with the moments are the associated excitation energy, half-life, spin, and parity of the nuclear state, and the experimental method employed. The literature has been surveyed through early 1988. For those cases for which no new or improved data has been reported since 1977, selected data from the compilation in Appendix VII of the {ital Table} {ital of} {ital Isotopes}, edited by C. M. Lederer and V. S. Shirley (Wiley, New York, 1978), with appropriate revisions, have been included.

A new approach to stroboscopic resonance measurements of the nuclear quadrupole interaction

A new stroboscopic resonance method for the measurement of the quadrupole interaction of long-lived nuclear isomers excited by pulsed beams with a fixed repetition frequency is demonstrated. The method utilizes the phenomenon of beats which occurs when a magnetic perturbation is introduced in the presence of a pure quadrupole interaction. The nuclear precession is thus controlled by the beat frequencies which can be varied by the external magnetic field which is oriented parallel to the symmetry axis of the crystal. Stroboscopic resonance can be achieved by varying thebeat frequency to be an integral multiple of the beam pulsing frequency. The method is demonstrated using the 398 keV level of69Ge excited and recoil implanted into a single crystal of tin by means of a heavyion reaction.

Sign of the electric field gradient in Cd Metal

Abstract The sign of the quadrupole coupling constant e 2 qQ of the 247 keV level of 111 Cd in Cd metal is determined to be positive, using the β-γ PAC technique. With Q >0, this implies a positive EFG for Cd verifying the recent theoretical prediction of Mohapatra et al.

Hyperfine interaction studies with pulsed heavy-ion beams

Heavy-ion reactions using pulsed beams have had a strong impact on the study of hyperfine interactions. Unique advantages offered by this technique have considerably extended the scope, detail and systematic range of its applications beyond that possible with radioactivity or light-ion reactions. This survey will cover a brief description of the methodological aspects of the field and recent applications to selected problems in nuclear and solid state physics illustrating its role. These include measurements of nuclear magnetic and electric quadrupole moments of high spin isomers, measurements of hyperfine magnetic fields at impurities in 3d and rare-earths ferromagnetic hosts, studies of paramagnetic systems, especially those exhibiting valence instabilities, and investigations of electric field gradients of impurities in noncubic metals. Future prospects of this technique will be briefly assessed.

Temperature dependence of the quadrupole interaction of69Ge Tl and113Sn Sn

The quadrupole interaction constants of69GeT1 and113SnSn were measured by means of the perturbed angular distribution technique as a function of temperature in the range of 80K≦T≦508 K and 80K≦T≦480 K, respectively. Isomeric states in69Ge and113Sn were populated by the heavy ion reactions56Fe(16O, 2p n) and100Mo(16O, 3n) and recoil implanted into polycrystalline Tl- and single crystalline Sn-backings. In the case of113SnSn, where the quadrupole coupling is weak, a special single crystal geometry was employed to enhance the sensitivity of the measurement. Within the limits of the errors the temperature dependence for both systems follows the empirical T1.5-dependence. While a strong temperature dependence comparable to InIn is observed for69GeT1, that for113SnSn is weaker than expected. The strength of the temperature dependence for113SnSn does not agree with the predictions of a lattice vibration model proposed recently for the temperature dependence of the quadrupole interaction.

Hyperfine field at strontium nuclei in nickel

The hyperfine field Hhf for SrNi has been measured by the TDPAD method using recoil implantation of an 8+ isomer of86Sr in Ni following heavy ion reactions. Two fieldsites populated about equally with Hhf(1)=−38.6(18) kOe and Hhf(2)=−54.2(11) kOe have been observed. These field values are well explained by conduction electron polarization alone.