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DOE OSTI2010

Nuclear Data Sheets for A = 163

The available data from the various reaction and decay studies leading to nuclides having mass number A=163 have been reviewed. These data are summarized and presented, together with adopted level schemes and properties, for nuclides from Eu (Z=63) through Os (Z=76). {sup 163}Eu represents a new addition to these nuclides. Level structures are now known for {sup 163}Ta and {sup 163}W through high-spin studies and recoil-decay tagging techniques. Several radioactive decays in this mass chain are not known at all or poorly established. No {beta} or {gamma}-ray data are available for {sup 163}Re-{sup 163}W-{sup 163}Ta-{sup 163}Hf {epsilon} decay chain. Those for {sup 163}Hf-{sup 163}Lu-{sup 163}Yb {epsilon} decay chain and {sup 163}Eu-{sup 163}Gd-{sup 163}Tb {beta}{sup -} decay chain are very sketchy. This evaluation is an update and revision of the previous one (2000Si01)

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

NASA NTRS2017

Experimental Observations of Nuclear Activity in Deuterated Materials Subjected to a Low-Energy Photon Beam

Exposure of highly deuterated materials to a low-energy (nom. 2 MeV) photon beam resulted in nuclear activity of both the parent metals of hafnium and erbium and a witness material (molybdenum) mixed with the reactants. Gamma spectral analysis of all deuterated materials, ErD2.8+C36D74+Mo and HfD2+C36D74+Mo, showed that nuclear processes had occurred as shown by unique gamma signatures. For the deuterated erbium specimens, posttest gamma spectra showed evidence of radioisotopes of erbium ((163)Er and (171)Er) and of molybdenum ((99)Mo and (101)Mo) and by beta decay, technetium (99mTc and 101Tc). For the deuterated hafnium specimens, posttest gamma spectra showed evidence of radioisotopes of hafnium (180mHf and 181Hf) and molybdenum ((99)Mo and (101)Mo), and by beta decay, technetium ((99m)Tc and (101)Tc). In contrast, when either the hydrogenated or non-gas-loaded erbium or hafnium materials were exposed to the gamma flux, the gamma spectra revealed no new isotopes. Neutron activation materials showed evidence of thermal and epithermal neutrons. CR-39 solid-state nuclear track detectors showed evidence of fast neutrons with energies between 1.4 and 2.5 MeV and several instances of triple tracks, indicating (is) greater than 10 MeV neutrons. Further study is required to determine the mechanism causing the nuclear activity.

Steinetz, Bruce M.↗

DOE OSTI2016

Hardness, elastic modulus, and wear resistance of hafnium oxide-based films grown by atomic layer deposition

The investigation of mechanical properties of atomic layer deposition HfO{sub 2} films is important for implementing these layers in microdevices. The mechanical properties of films change as a function of composition and structure, which accordingly vary with deposition temperature and post-annealing. This work describes elastic modulus, hardness, and wear resistance of as-grown and annealed HfO{sub 2}. From nanoindentation measurements, the elastic modulus and hardness remained relatively stable in the range of 163–165 GPa and 8.3–9.7 GPa as a function of deposition temperature. The annealing of HfO{sub 2} caused significant increase in hardness up to 14.4 GPa due to film crystallization and densification. The structural change also caused increase in the elastic modulus up to 197 GPa. Wear resistance did not change as a function of deposition temperature, but improved upon annealing.

36 MATERIALS SCIENCE↗