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The results of the study enable us to conclude the following: the β decay of249Bk is accompanied by an L series of x rays from the daughter product Cf. The yield of this radiation is low: ω(Lα+Lβ+ Lγ) ≈ 10−4 (β disintegration)−1, but because of the high specific β activity of249Bk, 1 μg of this isotope emits ∼3.7·105 x-ray quanta per minute. This enables us to detect a fairly small amount of Bk (∼0.01 μg) on the basis of x rays in a period of 5–10 min. The rapid accumulation of the daughter product249Cf does not interfere with the determination of the249Bk on the basis of x rays. Even when the mixture contains equal numbers of Bk and Cf nuclei, the ratio of the Lα lines corresponding to them is 0.46. Therefore the composition of a mixture of249Bk+249Cf can be determined on the basis of x rays over broad ranges of variation of the relative concentrations of Bk+Cf, roughly from 0.03 to 80. It is important to note that for relative measurements it is not necessary to prepare special specimens, since x rays with energies of 15–20 keV are not strongly absorbed in the solution and in the walls of the chemical vessel.

1. In the249Bk(15N, 4n)260Ku reaction an isotope of kurchatovium (element 104) is obtained which decays by spontaneous fission with a half-life of ∼0.1 sec. This result is in complete agreement with conclusions of earlier works [1, 3, 5] in which260Ku was synthesized in other combinations of target and particle:242Pu+22Ne,246Cm+18O. 2. The failure to observe260Ku with T1/2≈0.1 sec at Berkeley [10, 11] resulted from improper experimental arrangements and data processing. 3. The detection of the spontaneous fission of nuclei of an unknown isotope when background is properly considered and suppressed permits the identification of the Z and A of the nuclei under study.

In experiments on the irradiation of Pu242 and Pu239 with O16 and O18 ions in the extracted beam of the 310-era cyclotron of the Joint Institute for Nuclear Research, isotopes of 102254, 102253 and 102252 have been synthesized. Their properties are given below: Isotope T1/2, sec Eα, meV 102254 75±15 8.11±0.03 102253 95±10 8.01±0.03 102252 4.5±1.5 8.41±0.03

This paper investigates certain characteristics of p-n structures, prepared on a base of germanium obtained by the hydride method. The purpose of the study is to estimate the degree of purity of the germanium and its applicability for the preparation of the detectors with a high energy resolution. Monocrysstals of the p type were used. On completion of diffusion of the lithium in the samples by means of the procedure described, a protective groove was cut out. The apparatus spectra of Fe-55 and Am-241 are shown. The characteristics of the detectors obtained confirm the excellent quality and high purity of the germanium hydride.