An Acoustic Converter Used to Measure Ionizing Radiation Energy Loss

A monitor is proposed based on ultrasonic production when ionizing radiation passes through a medium. The recording element is a 0.2 mm aluminum plate mounted in a ceramic acoustic converter AC in the form of a wedge of thickness 2 mm. The low plate thickness minimizes the beam parameter distortion, while special technology used in the AC provides high sensitivity. The device has been calibrated in the proton beam from the ITEP accelerator at 200 MeV with 2·10⁹–6·10¹⁰ particles in a pulse and a pulse length of 70 nsec.     

Nonlinear conductivity and current-voltage characteristics of two-dimensional semiconductor superlattices

Electron transport and heating in a two-dimensional semiconductor superlattice with arbitrary orientation of the field (current) relative to the crystallographic axes is investigated in the approximation of constant energy and velocity relaxation times with electron-electron collisions taken into account. The nonlinear conductivity, average electron energies, and interrelationship between field direction and the current excited by it in an unbounded superlattice, as well as the current-voltage characteristics and the transverse electromotive force of a superlattice of finite width are found. Fiz. Tekh. Poluprovodn. 31, 308–310 (March 1997)     

A RHEED study of the transition from two-dimensional to three-dimensional growth in the InAs/GaAs system

A specially developed detection system and an analysis of RHEED diffraction patterns were used to investigate the dynamics of transition from two-dimensional to three-dimensional growth mechanism in the heteroepitaxial InAs/GaAs system. An analysis of the dynamics of the diffraction patterns was used for the first time to investigate the dynamics of formation of quantum dots. A time shift in the dynamic behavior of the diffracted intensity for diffraction patterns recorded at different angles was found. This shift is explained in terms of the size differences in the three-dimensional islands at the initial stage of decay of the pseudomorphic layer. InAs/GaAs quantum dots grown under certain conditions produce reflections at 45° relative to the principal reflections. This is evidence for the ordering of islands in the [001] and [010] crystallographic directions. Fiz. Tekh. Poluprovodn. 31, 1230–1232 (October 1997)     

Predicting Functioning Processes of Uniaxially Oriented Polymeric Materials

Fibre Chemistry - Traditionally, prediction of functioning processes of uniaxially oriented polymeric materials faces objective difficulties due to inhomogeneity of the rheological structure of...     

Mechanical properties of high-temperature alloy ZhS32 at 1150–1250°C

The mechanical properties of single crystals of alloy ZhS32 at a temperature of 1150–1250°C and deformation rates of 3 × 10⁻⁵, 10⁻⁴, and 10⁻³ sec⁻¹ are studied. The characteristics of true ductility in tests for long-term strength in a temperature range of 1150–1250°C are determined. __________ Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 1, pp. 38–40, January, 2006.     

Use of γ Radiation from Short-Lived Fission Products for Detecting <Superscript>235</Superscript>U and <Superscript>239</Superscript>Pu

It is suggested that γ radiation with E _γ > 4900 keV from short-lived fission products produced by thermal neutrons be used to detect ²³⁵U and ²³⁹Pu in samples. A time regime is substantiated: 120 sec irradiation, 60 sec holding time, and 120 sec measurement time. The contribution of the reaction (n, p) on fast neutrons is studied.__________Translated from Atomnaya Energiya, Vol. 98, No. 5, pp. 365–370, May 2005.     

Dependence of the surface morphology of ultrathin bismuth films on mica substrates on the film thickness

The results of studying the surface of 15- to 100-nm-thick bismuth films by atomic-force microscopy are reported. The near-linear character of the dependences of the average surface roughness and the average height of growth patterns on the film thickness is established. It is found that the average crystallite size increases, as the film thickness is increased. A slight dependence of the crystallite size on the film thickness is observed at thicknesses in the range of 27–70 nm.     

Extended depth of focus through imaging system’s phase apodization in coherent and incoherent cases

Effects of image distorting factors in the form of wave aberrations in the coherent and incoherent cases are simulated. It is shown that the defocus can be compensated for not only by use of a cubic phase distribution but also by means of other asymmetric phase functions, including those with a fractional power.