Detection of the Increment of an Instantaneous Phase in a Long-Base Laser Meter of Small Vibrations

A phase meter for processing signals of a laser meter of small displacements and vibrations at long base distances is described. Vibrations of objects are transformed into small increments of a signal phase at an RF carrier, which are detected by the phase meter and are outputted as signals proportional to microvibrations in the acoustic range. At a given carrier frequency f _c = 10.7 MHz, vibrations are detected within a band f = 3 kHz. Such vibrations produce phase fluctuations of 10^–42, which correspond to magnitudes of 1 nm for a laser wavelength 10 m.     

The Radiation-Monitoring Complex of the СПРУТ-VI System

The radiation-monitoring complex of the -VI system was installed on board the Mir orbital station and used to study the fine structure of the Earth's inner radiation belt in low and near-equatorial latitudes. The complex comprised a system of gas-discharge counters, as well as electron and proton spectrometers. The range of measured energies was 0.1–2.0 MeV for electrons and 0.1–10.0 MeV for protons. The possibility of changing the work program of the complex under spaceflight conditions was provided for.     

Time-of-Flight Characteristics of Scintillation Counters with Fine-Mesh Photomultipliers

The characteristics of the time-of-flight system of scintillation counters with the -527 and R5505 fine-mesh-dynode photomultipliers for high-magnetic-field environment were measured. Scintillation counters with thin plastic scintillators 1, 3, and 5 mm thick were designed to operate in comparatively strong stray magnetic fields of up to several kilogauss. The measurements were carried out in beams of the U-10 proton synchrotron (Institute of Theoretical and Experimental Physics) with proton, ⁺-meson, and ^–-meson momenta of 0.63, 1.03, and 1.28 GeV/c. For counters with scintillator sizes of 1 × 20 × 154 mm (BI-408) and 3 × 20 × 200 and 5 × 20 × 200 mm (Kuraray and SCSN-81), time resolutions of 45–180 ps were obtained. The time resolution of the scintillation counters, in which scintillators 20 mm thick and -527 photomultipliers were used, was found to be 50–80 ps.     

A Combination β–γ-Radiometer and Dose-Rate Meter with an Extended Dynamic Range

A MKC-07 –-radiometer and dose-rate meter based on Geiger–Muller tubes is described. By using an unconventional signal-processing method, it is possible to extend the dynamic range of the instrument by a factor of 10–50, depending on the type and number of detectors in use, and to significantly reduce the error in measuring time-dependent ionizing-radiation intensities. The combination radiometer and dose-rate meter is used to determine the characteristics of constant and nonstationary ionizing-radiation fields.     

Studying the Stability of Nanosecond Light-Pulse Sources Based on Blue GaN and InGaN Light-Emitting Diodes

The results of studying the stability of the parameters of nanosecond light-pulse sources based on bright blue light-emitting diodes are presented. These diodes were developed by the Nichia and Kingbright companies for calibration measurements in the HT-200 deep-water neutrino telescope, the MAGIC atmospheric Cherenkov telescope of high-energy quanta, and the wide-aperture Cherenkov detector of extensive air showers. The time stability of light sources is no worse than 1%. The changes in their light yields within a temperature range of –3 to +45°C are +7 and –9%, respectively.     

The PIBETA spectrometer for studying rare and forbidden decays of muons and pions

The construction and characteristics of the PIBETA spectrometer are described. This spectrometer is designed to implement a program of precise measurement of pion decay ^{+ 0} + e ⁺ + _e at the Paul Scherrer Institute (Switzerland). A spherical calorimeter, consisting of 240 crystals of pure CsI scintillator and embracing a solid angle of 3, is the main detector of the setup. In addition, the spectrometer is composed of an active collimator (which also acts as a beam degrader), a segmented active plastic target, two multiwire cylindrical proportional chambers, a 20-element cylindrical plastic hodoscope, and veto counters of cosmic muons.__________Translated from Pribory i Tekhnika Eksperimenta, No. 2, 2005, pp. 39–48.Original Russian Text Copyright © 2005 by Baranov, Kalinnikov, Karpukhin, Khomutov, A. Korenchenko, S. Korenchenko, Kravchuk, Kuchinskii, Mzhaviya, Rozhdestvenskii, Sidorkin, Tsamalaidze, Sakhelashvili, Frlez, Poanic, Li, Minehart, Smith, Stephens, Ziock, Bertl, Horisberger, Ritt, Schnyder, Wirtz, Ritchie, Supek, Kozlowski.     

Portable Electromagnetic-Acoustic Thickness Meters (EMAT)

Two varieties of contactless electromagnetic-acoustic portable thickness meters with autonomous power supply, created on the basis of up-to-date digital technologies, are described. The instruments implement a new highly efficient design of magnetic field concentrator developed on the basis of new magnetic materials. The -- thickness meter is equipped with a powerful microprocessor-based data processing system, which expands the capabilities of the instrument. The -100 thickness meter is a small-size and small-weight instrument. The main advantage of both instruments is that they can be operated on corroded untreated surfaces without the use of a contact fluid. Both instruments are suitable for testing through coatings of considerable thickness (up to 2 mm) and can be operated under workshop and field conditions.     

Spectrometry and Performance Characteristics of a BGO–ФЭУ-165 Scintiblock in a Temperatire Range of +25 to –140°C

The possibility of the joint operation of a -165 photomultiplier based on microchannel plates and a BGO crystal, which are cooled to a temperature required for the operation of a semiconductor Ge detector, is investigated taking into account the temperature dependence of proper PMT characteristics. The system was cooled from room temperature to –140°C for 8 h. The limiting temperature at which the PMT holds its serviceability was determined, and the temperature changes in the spectroscopic characteristics of the system (the energy resolution and signal-to-noise ratio) were studied.     

A Magnetometer Based on a Hall-Effect Transducer

An induction meter based on a Hall-effect transducer with in-phase signal suppression and thermostabilization circuits is described. It is powered by a 10³-Hz ac line. The maximum relative error in temperature measurements from 0 to 70°C does not exceed 0.7 % for magnetic fields of 50–100 T, 0.4% for 0.1–1 mT, and 0.1% for 1–625 mT. In the range of 50–500 T, the error is determined by an in-phase signal. The contribution of the total temperature error is 0.01% per 50°C. Depending on the induction of the measured magnetic field, the resolution changes from 0.12 to 19 T.     

Identification of Characteristic Features of Envelopes of Testing Pulses with the Help of the Diade Convolution Adaptable to Noise Level: I. Identification of Types of Characteristic Features

A method has been suggested for binary coding of envelopes of measured pulses from eddy-current transducers. The method enables one to identify their characteristic features of various types, such as leading edge, trailing edge, maximum, minimum, horizontal portion, start point of leading edge, end point of leading edge, start point of trailing edge, and end point of trailing edge, using weighted sums of no more than four Hadamard-ordered Walsh functions with numbers 0, 1, 2 ^n–1, and 2 ^n–1 + 1. The paper demonstrates the existence of obvious diade correlations of coded combinations corresponding to specific fragments with both one another and distortions of a current sampling simulated by adding an error vector. These properties make possible an identification of types of characteristic features in current samplings of binary data with four levels of a noise immunity, which are selected in the process of adaptation to the noise intensity with due account of the significance of identified features.     

A Self-Initiated Periodically Pulsed Light Source on Chlorine and Krypton Chloride Molecules

An electric-discharge light source, operating in the spectral range of 170–270 nm on a system of bands of Cl₂ ( = 200 and 257 nm) and KrCl ( = 222 nm) molecules is described. The radiator is pumped by a low-pressure volume discharge in a spherical anode-flat cathode system of electrodes with an interelectrode distance of 6 cm, so that the plasma has no contact with the quartz envelope of the lamp. The working mixtures are P(Kr)/P(Cl₂) = (40–640)/(40–280) Pa. When a dc voltage U 1 kV is applied to the discharge gap, a volume discharge exists only in a periodically pulsed mode (f = 0.1–50 kHz) and represents a source of short-wave radiation with a cylindrical working surface (1 cm in diameter and 6 cm long) and a mean radiation power of 3 W.     

The possibility of testing the structural state of highly-deformed high-carbon steels by the magnetic method

The influence of cold plastic deformation on phase transformations and on the magnetic properties of powder specimens of the Fe-5-at. % C alloy modeling U12 high-carbon steel has been investigated in the context of nondestructive testing. It has been shown that under high plastic deformation dissolution of cementite Fe3C occurs by the scheme -Fe + Fe₃C -Fe + (Fe₃C)_d + -Fe + Am(Fe-C). An increase in the rate of plastic deformation of powders decreases the coercive force from 50 to 13 A/cm due to the low coercivity of the #x03B1;-Fe and Am(Fe-C) phases. The structural state of high-carbon steels following a strong cold plastic deformation can be determined by measuring two magnetic parameters: the coercive force, and the temperature dependence of differential magnetic permeability.Translated from Defektoskopiya, Vol. 40, No. 7, 2004, pp. 42–52.Original Russian Text Copyright © 2004 by A.I. Ulyanov, Arsenteva, Zagainov, A.L. Ulyanov, Elsukov, Dorofeev.     

Analysis of the diamond sawing process

There are three methods in use for separating diamonds, i.e. by cleaving, by laser beam and by sawing. Sawing is one of the main methods used for this purpose. This operation is carried out on special sawing machines equipped with a sawing disk blade, 0.04–0.14 mm thick and 76 mm initial diameter. The rotational velocity (n) of the disk is between 6000 and 12 000 r.p.m. Diamond powder is embedded in the periphery of the disk. The outcome surface of a diamond after the sawing operation must be flat and smooth, Whenever such a surface is actually obtained, the polishing time and the loss in size and weight of the diamonds are reduced.In the present work, the positioning of the diamond to be sawed, with respect to an embedded particle in the disk, to create a favourable cutting angle is discussed. This would make it possible to reduce the rake angle () to near-zero, and thereby the cutting forces. Furthermore, a method to control the morphology and grain size of the diamond powder to be used in the cutting was developed.In the diamond industry, two modes of sawing operations are in practice. One uses the periphery of the disk for the sawing while the other employs a circular hole in the centre of the disk. Analysis of the two modes showed that the hole mode is more promising, as the design in that case requires tensioning of the disk and makes for better lateral stability during the sawing process. In addition the tangential and the radial stresses, developed in both sawing methods, were calculated. To support the above, data was obtained from existing literature and analysed.Nomenclature n rotational velocity of the disk, r.p.m. - rake angle, degrees - back clearance angle, degrees - cutting angle, degrees - m relative frequency - f feed - b disk radius, mm - a disk hole radius, mm - r current disk radiusb>r>a, mm - density of disk material, kg m^–3 - angular velocity - Poisson ratio of disk material - g acceleration of gravity, m s^–2 - _r radial stress, kg cm^–2 - _{r max} highest radial stress, kg cm^–2 - _t tangential stress, kg cm^–2 - tangential stress at outside circumference, kg cm^–2 - tangential stress at inside circumference, kg cm^–2     

The СПРУТ-VI Instrument Complex for the Mir Orbital Station

The basic elements of the instrument package program for orbital stations are presented. The characteristics of the -VI equipment developed for the Mir orbital station within the framework of this program are described. This equipment allows the simultaneous recording of the characteristics of near-earth space (electron, proton, and nucleus fluxes, magnetic fields, and low-frequency electromagnetic waves) and their effect on the elements of spaceborne equipment and systems. The mass of the equipment is 16 kg; the power consumption is no more than 20 W.     

A continuously emitting electric discharge UV lamp

A UV lamp pumped by a dc-current glow discharge in a mixture of helium with iodine vapors inside a quartz discharge tube with an interelectrode distance of 50 cm is described. For the power deposited in discharge (W _el 200 W), the total power emitted by the lamp in the spectral range 200–350 nm is as high as 27 W with an efficiency of 18 %. The lamp service life in the gas-static mode is 400–500 h. The emission is distributed almost equally between the spectral line of iodine atoms = 206.2 nm) 0.12 nm wide and the electron vibrational bands of I₂(B-X) molecules _max = 342 nm). The optimal helium partial pressure is 600–800 Pa.Translated from Pribory i Tekhnika Eksperimenta, No. 1, 2005, pp. 119–121.Original Russian Text Copyright © 2004 by Shuaibov, Grabovaya.     

A Thin-Film Sensitive Element Based on Copper-Doped As20Se80 Glasses for a Precision Temperature Sensor

A sensitive resistive element based on copper-doped As₂₀Se₈₀ glasses for use in a temperature sensor is described. The sensitive element operates in a temperature range from –70 to +70°C. Its electrical resistance is 100 k and linearly depends on the temperature. The sensitivity of the element is 1 k/°C; the accuracy of temperature measurements is 0.01°C.     

Error Corrections in a Sampling Sliding Along a Pulse Envelope Based on Decoding Tables

Code combinations of 2 ⁿ symbols +1 and –1 suggested for identification of characteristic features leading edge, trailing edge, maximum, minimum, horizontal portion, start of leading edge, end of leading edge, start of trailing edge, and end of trailing edge in a binary-code envelope of a pulse measured by an eddy-current transducer (ECT) scanning a tested surface generate a group code. This group code ensures for four levels of noise immunity the maximal likelihood in identification of reference sequences distorted by noise. The structure of a product code, which is also generated by the reference fragments, results in a higher capability of correcting for errors in moving samplings of signal envelopes, in particular, it reduces the degree of uncertainty in identification of the most important features of ECT pulses. The paper suggests simple decoding algorithms and regular logical structures that provide a high efficiency of the procedure eliminating errors in binary sequences of coded envelopes.     

Effect of surface contamination on the UHV tribological behavior of the Cu(111)/Cu(111) interface

Friction and adhesion measurements have been made using two Cu(1 11) samples modified by the presence of atomic adsorbates. Copper surfaces with 10–15 Å thick contaminant films resulting from exposure to the atmosphere exhibited a static friction coefficient of _s = 0.75 ± 0.18. A sharp increase in the friction coefficient was observed when the contaminant layer was reduced to submonolayer thickness by sputtering and for the cleanest Cu(111) surfaces studied the static friction coefficient was _s = 4.4 ± 1.3. To further investigate the tribological effect of submonolayer coverages of surface contamination adhesion experiments were performed using surfaces modified with sulfur adsorbed at coverages in the range _s = 0.0–0.39 ML (saturation). The adhesion coefficient of the clean surfaces (_ad = 0.69 ± 0.20) was markedly reduced by the presence of 0.05 ML of sulfur and decreased monotonically with increasing sulfur coverage to a limiting value of _ad = 0.26 ± 0.07 at _s = 0.39.     

Accelerator of the НГ-12И neutron generator as an implanter of hydrogen ions

The use of an updated accelerator of the -12 neutron generator as a high-current implanter of hydrogen ions (protons and deuterons) with energies of 175–210 MeV into wafers made of crystalline silicon is described. The ion-beam scanning system used ensured nonuniformity in the irradiation of wafers with a diameter of 100 mm of <10%, which allowed the production of silicon-on-insulator wafers by the hydrogen splitting technique. The required particle fluence was 10¹⁷ cm^–2. A slight refinement of the setup allows wafers with diameters of up to 200 mm to be irradiated. The design features of the setup as they apply to different temperature conditions (down to a temperature close to that of liquid nitrogen) of the irradiation of 100-mm-diameter wafers are described.Translated from Pribory i Tekhnika Eksperimenta, No. 1, 2005, pp. 126–129.Original Russian Text Copyright © 2004 by Stepovik, Mokichev, Magda, Kiryushkin, Kozikov, Semkov, Kurochkin, Lukin, Khmelnitskii, Popov.     

Generation of High-Voltage Subnanosecond Pulses with a Peak Power of 700 MW and Repetition Frequency of Up to 3.5 kHz

Test results of a combined subnanosecond modulator with an output impedance of 45 , which incorporates an all-solid-state high-voltage nanosecond charging device (with an inductive energy storage and a semiconductor opening switch) and a pulse sharpener with gas-filled gaps, are presented. The sharpening and cutting spark gaps filled with hydrogen at a pressure of 100 atm ensured the formation of stable pulses with amplitudes of –(180–200) kV and durations of (400–700) ps at a repetition frequency of up to 3.5 kHz. An average output power of 1.4 kW was achieved for the modulator's burst-mode operation with a number of pulses in a packet of 10⁴at a maximum pulse repetition rate.