The results of experimental studies of the shock-induced particle ejection (“dusting”) from a free rough ( R z = 20) surface of lead and copper samples into an evacuated medium are presented. The experimental methods were based on different physical principles. To determine the size of particles by shadow laser-optical imaging more efficiently, a narrow strip was isolated in the center of the free surface of a sample from which an optically transparent stream of particles was ejected. The rest of the surface, substantially larger in size, ejected particles, parameters of which were reliably recorded using optical heterodyne interferometry detection, radiographic imaging, and piezoelectric techniques. This made it possible to obtain more reliable data on the particle size distribution, the velocity of the front of a particle flux, and the density (weight) distribution of the flow in the direction of its motion, necessary to refine the existing models and create more reliable models to describe the phenomenon. Using lead and copper samples, the material of which melts or does not melt under shock wave loading in selected close conditions (amplitude of the shock wave and roughness of the free surface), made it possible to clearly demonstrate the effect of melting on the qualitative pattern and quantitative characteristics of the shock-induced dusting process.

In view of the possible effect of contamination of a plasma by metal particles on the operation of a number of facilities or on the detection of the motion of liners by Doppler methods, a particular attention has been recently focused on the problem of the ejection of particles from the shock-loaded free surface of a sample or on the “dusting” problem. Most information concerns the dusting source associated with the roughness of the surface, manufacturing technology, and the defectiveness and aging of a material. Factors affecting this process such as the profile and amplitude of the pressure on the front of the shock wave arriving at the free surface of the sample, the presence of the gas in front of the free surface, and the pressure in this gas are less studied.

This work presents the results of experiments on the compression of a spherical copper shell loaded by the detonation of a plastic explosive layer. A U-70 accelerator is used for radiographic recording of the convergence of the shell to the center, and metallographic analysis of the copper shell preserved after the experiment is performed. The results of multiframe proton radiography of the convergence of the inner boundary of the copper shell to the center are compared with the results of numerical simulations.

A proton radiography facility with the use of magnetic optics (PUMA proton microscope) has been developed at the TWAC-ITEP accelerator-accumulator facility (the ITEP terawatt accumulator) for measuring the substance density distribution inside static and dynamic objects using the proton beam with an energy of 800 MeV. The proton radiographic image of an object of investigation placed in the object plane of the setup is formed in the plane of the detector with magnification K = 4 with the aid of the magneto-optical system consisting of four quadrupole lenses on permanent magnets. The PUMA facility is intended for measuring objects with an areal density of up to 20 g/cm 2 with a field of vision as large as 20 mm in diameter. The spatial resolution of radiographic images depends strongly on the areal density of the object of investigation. For the PUMA facility, the spatial resolution varies from 60 to 115 μm at an areal density of 0.46–17 g/cm 2 , respectively. The dynamical state of substance can be investigated in four consecutive radiographic images, since the time structure of the proton beam consists of four pulses, each with a duration of 47 ns (full width at half maximum (FWHM)) and an interval of 250 ns between them. This article is devoted to the description of the proton microscope construction. The main metrological characteristics of the facility are described using experiments with static and dynamic objects as an example.

In recent years studies of shock and detonation wave phenomena at extreme dynamic conditions were performed at proton radiography facility developed at the 800 MeV proton beam line of ITEP Terawatt Accelerator (ITEP-TWAC). The facility provides a multi-frame imaging capability at 50 μm spatial and 70 ns temporal resolution. The results of latest studies conducted there are presented, including explosion and detonation of pressed and emulsion high explosives, shock-induced dense non-ideal plasma of argon and xenon and shock loading of non-uniform metal surfaces. New compact explosive generators developed specifically for a use at proton radiography facilities are also presented.

The initiation of detonation of plasticized TATB by shock loading using an initiator pressure charge of an HMX based explosive was studied by radiography. In the experiments, the size of the initiator and the initial density of the TATB charge were varied. During initiation of TATB detonation, part of the material did not react, forming so-called dark zones. As the process goes on, the detonation wave bends around the dark zones, without initiating the material within them. The evolution of the area of dark zones was compared for samples of different initial density and initiators of different sizes. The characteristic boundaries and X−t diagrams of detonation front propagation under different loading conditions were constructed from images of the explosive process. Density distributions behind a divergent detonation wave front at different times were obtained and analyzed.

Detonation initiation in a composite explosive based on HMX and TATB loaded by a divergent shock wave was studied on a U-70 proton accelerator using proton radiography. Density distributions behind the initiating shock front at various times were obtained. Detonation failure due to collision of shock and detonation waves was studied for a plastic-bonded TATB sample using radiography. Characteristic features of the explosive transformation under shock-wave loading were determined from the images obtained.

This paper gives the results of investigation of fast hydrodynamic processes by flash proton radiography based on the U-70 proton synchrotron of the Institute of High Energy Physics (IHEP). The physical setup for proton radiography with a maximum energy of the proton bunch up to 70 GeV and intensity up to 1.5 · 10 13 protons per cycle records up to 29 frames in one projection with the minimum interframe time interval of 165 nsec. At present, the recording area is ≈60 mm in diameter, with the prospect of increasing to 250 mm. The duration of the proton bunches equals 20–30 nsec and can be reduced to 10–15 nsec. Since 2004 and up to now, the Russian Federal Nuclear Center-Institute of Experimental Physics (RFNC-VNIIEF), together with IHEP, have performed static and dynamic experiments on this setup to study: the initiation and propagation of detonation in condensed explosives, shockwave propagation in inert materials; hydrodynamic instabilities in metals; dynamic deformation and fracture of liners and plates; spall fracture; the formation of shaped-charge jets and their interaction with obstacles; other applications of physics of the explosion. The proton radiography complex based on the U-70 accelerator and designed by researchers of RFNC-VNIIEF and IHEP is a unique tool for studying fast processes. The method of proton radiography opens up new opportunities for Russian researchers: multiframe recording, almost unlimited thickness of the objects studied, high spatial resolution, enormous dynamic recording range.

Описана радиографическая установка ускорителя протонов с энергией 70 ГэВ ГНЦ ИФВЭ. Установка создана с использованием имеющейся инфраструктуры в начальной прямолинейной части канала инжекции. Линзы канала инжекции предназначены для транспортировки протонного пучка из У-70 в ускорительно-накопительный комплекс и имеют диаметр 100 мм. Установка рассчитана только на энергию 50 ГэВ с полем обзора 60 мм и позволяет получать при наличии некоторых потерь в канале изображение объектов с оптической толщиной свыше 300 г/см2. Оптическое разрешение установки составляет 0.25 мм. В период 2004–2008 гг. на установке проведен ряд экспериментов с многокадровой регистрацией быстропротекающих процессов. При проведении динамических экспериментов использовались малогабаритные взрывозащитные камеры, а также измерительная система мониторинга состояния камеры и окружающей среды.

A radiographic facility for the 70-GeV proton a ccelerator of the Institute for High Energy Physics is described. The available infrastructure in the initial straight part of the injection channel is used in the facility. The 100-mm-diameter lenses of the injection line ar e intended for transportation of the proton beam from the U-70 accelerator to the accelerating-storage complex. The facility has been designed only for an energy of 50 GeVwith a viewfield of 60 mm and used for imaging of samples with an optical density of > 300 g/cm(2) in the presence of some losses in the line. The optical resolution of the facility is 0.25 mm. A set of experiments aimed at multiframe recording of fast processes were conducted on the facility in 2004-2008. Small-sized explosion-proof chambers, as well as the measuring system for monitoring the state of the chamber and environment, were used in the dynamic experiments.

The details of the ejection of 20- to 200-µm particles with a velocity of 1.0-1.5 km/s from the surfaces of lead and steel samples with a roughness of 5-40 µm (Rz 5-Rz 40) when shock waves with an amplitude of 15 and 27 GPa reach them are visualized with a high-speed streak camera with a CCD matrix and pulsed laser illumination at a pulse duration of 4 ns. The size and velocity distributions of the particles are obtained.

A hierarchical approach to the construction of compound distributions for process-induced faults in IC manufacture is proposed. Within this framework, the negative binomial distribution is treated as level-1 models. The hierarchical approach to fault distribution offers an integrated picture of how fault density varies from region to region within a wafer, from wafer to wafer within a batch, and so on. A theory of compound-distribution hierarchies is developed by means of generating functions. A study of correlations, which naturally appears in microelectronics due to the batch character of IC manufacture, is proposed. Taking these correlations into account is of significant importance for developing procedures for statistical quality control in IC manufacture. With respect to applications, hierarchies of yield means and yield probability-density functions are considered.