10 Be in commercial beryllium

¹⁰Be has been observed at a level of about 10^?14 in four commercially available beryllium compounds. The possibility that this ¹⁰Be arises from cross-talk in the ion source has been eliminated. On the other hand, beryllium oxide extracted from beryl crystals found at a depth of 30–40 feet in a lithium mine in South Dakota shows no indication of containing ¹⁰Be. An upper limit on its ${}^{10}\text{Be}\text{:}{}^9\text{Be}$ ratio is 1.7 × 10^?15 at the 95% confidence level.     

Aging of beryllium

A survey of studies devoted to the possibility of increasing the plasticity of technical-purity beryllium within the temperature region 400–600°C is given. It is shown that the heat treatment of beryllium at 600–800°C leads to the deposition of the superfluous phases from the supersaturated solution. This is accompanied by a substantial change in the properties of the metal, in particular, the plastic and strength characteristics, hardness, creep, and electric resistance. The results of metallographic, electron microscopic, electron diffraction, x-ray diffraction, and other investigations of the microstructure of beryllium in various states are cited. The mechanism of the aging of beryllium is described on the basis of the available data, and practical conclusions are drawn on the possibilities of increasing the plasticity of beryllium at high temperatures.Translated from Atomnaya Énergiya, Vol. 19, No. 2, pp. 144–153, August, 1965     

Migration of helium in irradiated beryllium

Kurchatovskii Institute, Russian Scientific Center. Siberian Branch, Scientific Research and Design Institute for Power Technology. Translated from Atomnaya Énergiya, Vol. 73, No. 2, pp. 157-158, August 1992.     

State of helium in irradiated beryllium

Experimental data are presented on the change of the pycnometric density and unit-cell volume of beryllium irradiated in an SM reactor to neutron fluence 14·10²² cm^–2. The behavior of the unit-cell volume as a function of the neutron fluence is similar to the data for other metals. This and data on the volume change in beryllium oxide, where a large amount of gas is also formed during irradiation, make it possible to evaluate critically the assertion that helium forms a solid substitution solution. It is proposed that helium is confined in small accumulations.     

Radiation damage in beryllium oxide single crystals

Radiation damage in single crystal BeO has been studied using ⁶⁰Co gamma, 2 MeV electron, and epithermal neutron irradiations. The temperature of irradiation and the accumulated dose were kept within the range in which the change in the $\text{a}$ lattice parameter has been found to predominate. The observed changes produced by ⁶⁰Co irradiation are attributed to ionization of crystal impurities. Both electron and neutron irradiation produce optical absorption bands at about 5.25 and 6.5 eV. The energy at which the band peak occurs varies slightly with the conditions of irradiation and from sample to sample. No e.p.r. resonance could be correlated with either band. Neither F⁺ nor V^? centers were observed. The data from the annealing of these two bands indicate that they arise from different but related defects and that they are not due to simple point defects.     

Accurate wavefunction for atomic beryllium

We describe the most accurate to date configuration-interaction wavefunction for Be ground state Ψ = ΣΦ_K^(p)a_Kp where Φ_K^(p) is a LS eigenfunction for configuration K and electron coupling p. We present tables for the coefficients a_Kp associated with the invariant portions of the wavefunction. We also specify the electron couplings and phase factors of the Φ_K^(p)'s and the orbital basis ψ_ilm = R_il(r)Y_lm(θ,φ) characterized by R_il = ΣS_jla_jli and S_jl = N_jlr^(n_j?1) exp (?Z_jlr). Our wavefunction, after inclusion of approximate relativistic and radiative corrections, gives a total electronic energy for ⁹Be of ?14.668 451 (28) a.u. in agreement with the latest experimental-theoretical value of ?14.668 452 (2) a.u.