W. A. Steyert

Nuclear orientation and parity-mixing studies of the decays of 171Er and 169, 175Yb

Abstract Angular distributions of γ-radiations emitted by 171Er and 169, 175Yb have been studied from radioactive samples polarized at low temperatures. The magnetic hyperfine field of Er in ZrFe2 was deduced to be 8.3±1.0 MG, based on the anisotropies of the 171Tm γ-rays. The magnitudes of the 159Yb and 175Yb magnetic moments were deduced to be 0.63±0.09 μN and 0.40±0.05 μN, respectively, based on γ-ray anisotropies following the decay of samples polarized in Au. Gamma rays from 177Lu were observed to be emitted isotropically, indicating the lack of Lu polarization in Au. The E2/M1 and M2/E1 multipole mixing ratios were deduced for most of the mixed γ-transitions in 169, 171Tm and 175Lu. Investigations of the forward-backward asymmetry of the angular distributions of a number of strongly hindered γ-transitions in 169, 171Tm and 175Lu revealed no effect attributable to parity mixing in the nuclear states.

54Mn in Fe for ultralow temperature thermometry

Experimental investigations into the accuracy of nuclear orientation thermometry are reported.54Mn in iron, a primary thermometer useful from 2–40 mK, gives consistent thermometry using both scintillation (3×3 in.-NaI) and solid-state (40-cc-Ge) detectors.60Co-in-iron temperatures are consistent with the54Mn temperatures above 10 mK, but are about 10% higher at 4 mK.125Sb in iron registers a temperature that is perhaps 2 or 3% lower over the 4–15 mK region. Some of the techniques required for the utilization of this type of thermometry are discussed.

Angular distribution of gamma rays resulting from polarized 124Sb, 192Ir and 194Ir

Abstract A 3He-4He dilution refrigerator coupled with adiabatic demagnization has been used to polarize 124Sb, 192Ir and 194Ir dissolved in an iron foil. The angular distributions of the emitted γ-rays are measured. The magnitude of the 124Sb magnetic moment is determined to be ±(1.42±0.1) μN. The angular momentum carried off in many of the β-decays and a number of γ-decay mixing ratios in the daughter nuclei are reported. These results include the observation that 67 ± 12 % of the 2313 keV 124Sb β-rays carry off 2 units of angular momentum, an unusually large proportion. Also, in the 2091 keV E1 γ-rays of 124Te, there is a 0.07±0.03 M2 amplitude admixture.

NUCLEAR ORIENTATION STUDY OF THE DECAY OF

Investigations of the angular distribution of

sup 239

\ensuremath{\gamma}

Np POLARIZED IN ZrFe

radiation from

sub 2

^{239}\mathrm{Np}

: PARITY MIXING IN

polarized at low temperatures in Zr

sup 239

{\mathrm{Fe}}_{2}

Pu AND NUCLEAR STRUCTURE OF

have suggested small forward-backward asymmetries for several of the hindered