Energy features of fissile nuclei at the scission point for various fission modes

Mass-spectroscopicdata on the yields of heavy products originating from the thermal-neutron-induced fission of ²³⁵U nuclei are presented over broad ranges of mass numbers A (125 ? A ? 155), kinetic energies E _k (40 ? E _k ? 80 MeV), and effective ion charges z* (18 ? z* ? 29). The potential energy of a fissile system at the scission point is analyzed with allowance for the positions of the minima that correspond to the most probable ways of separation of the system for the standard (S2) and superasymmetric (S3) fission modes.     

Studying the interaction of 10-keV electrons with a dielectric surface

The grazing incidence interaction of a 10-keV electron beam with a planar surface of plexiglass is studied experimentally. Moreover, the electron passage through flat channels formed by such surfaces is investigated. The experiments reveal the presence of a guiding effect of the electron passage as in the case of a glass surface. However, there are some features, such as the existence of an initial elevation angle for the case of negative inclination angles of the plate. The formation of self-consistent charge on the surface of the plexiglass and its drain when the current is turned off occur more slowly than on the glass surface. This fact points to the difference in the surface conductivity of insulators.     

Thermal expansion of niobium diselenide in the basal plane at low temperatures

The thermal expansion of a high-quality 2H-NbSe₂ single crystal is precisely measured in the basal plane and the temperature range 5.7–50 K. An anomaly of the thermal expansion in the basal plane is detected, and it is found to be caused by a superconducting transition. The change in thermal expansion coefficient α _ab is used to calculate the pressure derivative of the critical temperature (dT _c /dp _ab ) = (19.0 ± 2.0) × 10^?9 K/Pa, and this derivative agrees well with the reported data. An additional anomaly, which indicates a phase transition, is also detected in the pretransition range. The nature of the detected phase transition is discussed.     

Development of an external cavity quantum cascade laser spectrometer at 7.5 μm for gas detection

We report the development of an external cavity quantum cascade laser spectrometer at 7.5 μm. The quantum cascade laser and its anti-reflection coating were specially developed for this application. We provide details of the external cavity design and data processing. A continuous wave emission is demonstrated from 1,293 up to 1,350 cm^?1. A preliminary test of the spectrometer was realized by measurements on acetone and phosphoryl chloride.