Interferometric Methods for Surface Testing. High-Order White-Light Interferometer

A high-order white-light interferometer for three-dimensional fast noncontact testing of optical surface profiles is described. The device ensures measurements of absolute flatness deviations to an accuracy of /1000 within a wide technological field of 80 mm (the resolution in the plane is 0.1 mm).     

A Microwave Generator on a Gunn Diode with an Open Resonator

An oscillator on a Gunn diode with an open resonator is described. The diode is located in a cut of one of two mirrors, which consists of two parts. This mirror simultaneously plays a role of the electrodes and cooling system. The main characteristics of the oscillator operating at a frequency of 40 GHz are as follows: 30 mW (the output power), 20 kHz (the oscillation linewidth), 10^–7 (the relative short-term stability), and up to 2 GHz (the range of mechanical tuning within a single zone at a slope of the tuning characteristic of 1.19 GHz/mm).     

A Shipborne Laser Fluorimeter for Studying Sea-Water Fluorescence Spectra

A shipborne laser fluorimeter making it possible to determine promptly the concentration of chlorophyll A in sea water is described. The measurement error is 35% at chlorophyll concentrations of 0.1–3 g/l, and the single-measurement duration is 1 min.     

Time-of-Flight Trigger Based on a Time-to-Amplitude Converter

A time-of-flight trigger based on a time-to-amplitude converter and differential discriminator is described. The trigger has a short decision time (60 ns) and high (100%) efficiency of useful event selection.     

A Study of Distortions in Double-Sided Emulsion Films by FoMos

FoMos makes double-sided emulsion tapes. Films of desired size cut from such tapes are used as emulsion trackers. The technique for measuring distortions is described, and the results of measurements are presented for several films cut from different sections of a standard piece of double-sided tape with a length of 7 m and a useable width of 20 cm. The standard plastic base of the tape under investigation is 190 m thick; 50-m-thick layers of diluted PX3 emulsion–gel are applied to its opposite sides.     

Capacitive Discharge Excilamps

UV radiating sources on KrCl ( 222 nm), XeCl ( 308 nm), and XeBr ( 282 nm) molecules excited by a capacitive discharge are described. The sources have a simple design of the radiator and are characterized by a high radiation efficiency (up to 25%), a lifetime of up to 2500 h, and a radiation band half-width of 4–8 nm.     

Efficient Generation of Microwave Oscillations at Harmonics of the Conductance of a Gunn Diode

Basic characteristics of prototype oscillators operating at the second (19 GHz) and third (36 GHz) harmonics of the negative conductance of a 3715 Gunn diode are presented. The output power of these oscillators is 1.5–8.0 mW and the range of electronic frequency tuning is up to 390 MHz.     

Optical Transmission of Silica Fibers Exposed to γ Rays

The results of a study of the dynamics of an induced attenuation of light in optical fibers exposed to radiation are presented. The doses were as high as 10 and 100 Mrad at dose rates of 10 and 100 rad/s. Two types (silica–silica and polymer–silica) of fibers produced by INFOS (Russia), Polymicro (USA), and Hestibel (Turkey) were investigated.     

An Energy Source Based on Helical Explosion–Magnetic Generators for High-Impedance Loads

A transportable standard module developed at the Institute of Experimental Physics as a component of an energy source for modeling current pulses of positive lightning is described. The source is designed as a combination of several unified helical explosion–magnetic generators with output transformers and an inner diameter of the stator of 200 mm. According to our calculations, the source generates current pulses with an amplitude of up to 100 kA in loads with an inductance of 100 H and a resistance of several tens of ohms. The results from testing a typical module operating with a circuit having an inductance of 100 H and a resistance of 4 are presented. The experimental data coincide well with the results of a mathematical simulation of the module's operation.     

A Position-Sensitive Detector for the Polarized-Neutron Spectrometer

A linear detector of thermal neutrons, developed at the Laboratory for High Energies (Joint Institute for Nuclear Research), is used in the polarized-neutron spectrometer of the -2 reactor (JINR). The data are acquired in the regime of frame-by-frame survey to select neutrons with a wavelength = 1–12 Å by the time of flight. The neutron-detection efficiency is 70% for a wavelength of 2 Å. The detector exhibits a low sensitivity to -rays, a differential nonlinearity of 1.5%, and a spatial resolution of 1.5 mm at counting rates of 10⁵events/s.     

A Coordinate Detector for Studying Horizontal Fluxes of Cosmic Rays

A DECOR coordinate detector is a multilayer system of plastic streamer tube chambers located around a NEVOD Cerenkov water calorimeter. The basic characteristics of the detector are as follows: the area is 100 m², the angular resolution is 1°, and the space resolution is 1 cm. The structure of the detector, data acquisition and trigger systems, and results obtained during the operation of a pilot assembly (8 chamber layers and a working area of 8.4 m²) are given.     

Single-Electron Characteristics of a ФЭУ-184U Photomultiplier Tube

Single-electron and time characteristics of a -184U photomultiplier tube with a uviol window are presented. The -184U single-electron resolution can reach a value of 63–64%, and, in case of single-electron light-striking of the photocathode, the photoelectron transit time distribution (full width at half maximum) is 6 ns.     

A Gas-Ion Ribbon Beam Source with a Wide-Aperture Cold Hollow Cathode

A source of gas-ion ribbon beams on the basis of a glow discharge in a prolonged electrode system with a closed drift of fast electrons is described. This drift ensures a uniform plasma ion emission in the transverse direction relative to the magnetic induction vector. A discharge with a current of up to 3.5 A and a voltage of 400–600 V in a magnetic field of 6 mT is maintained under a gas flow of 40 cm³atm/min and ensures a saturation ion current density from plasma of up to 4 mA/cm² (±5%) over a length of 50 cm. Using slit-type optics with an aperture of 50 × 1 cm, a ribbon beam with a current of up to 0.2 A and an energy of argon ions of up to 25 keV has been obtained. Methods of the concentration of discharge near the emissive slit and the effect of the electron drift on the ion emission from the plasma are considered. The optimal conditions for ion beam formation are determined.     

A Subnanosecond Voltage Divider on Coupled Lines

The divider consists of two electrically and magnetically coupled coaxial lines inserted one into the other and having a single common outer conductor. One is an oil-filled line transmitting the main high-voltage pulse, and the other is a low-impedance measuring line, whose input is connected through a cable to the input of an oscilloscope. The experiment has confirmed the calculated division factor of 300 and a reproduction of the shape of the recorded pulse by the divider without distortions. The divider was used for recording bipolar pulses with ±120-kV amplitudes, a duration of 0.8 ns, and a rise time of 0.2 ns.     

A Helical Magnetic-Cumulation Generator with a Compact Transformer

Experimental data on a helical magnetic-cumulation generator with an output step-up transformer formed by two coaxial solenoids is presented. The inner diameter of the helix is 50 mm. Compared with the transformers described earlier, this transformer has a smaller size. The transformer can feed an energy of 1 kJ into a 100-H high-impedance load.     

Baikal-2 Two-Channel Photomultiplier Tube

A two-channel photomultiplier tube is developed to use as part of a QUASAR-370 hybrid photodetector. The test results of the amplitude and time responses are described. The time resolution is 340 ps; the peak-to-valley ratio of the charge distribution of single photoelectron pulses is 1.5.     

The Tribological Properties of Monolayer KCl Films on Iron in Ultrahigh Vacuum: Modeling the Extreme-Pressure Lubricating Interface

The friction coefficients of thin KCl films deposited onto clean iron in ultrahigh vacuum are measured using a tungsten carbide tip. A rapid decrease is found in the friction coefficient from 2 for clean iron to 0.27 ± 0.03 after the deposition of 40 Å of KCl. Based on previous contact resistance measurements, this was proposed to be due to the completion of the first layer of KCl. The first-layer KCl coverage was measured by adsorbing deuterium onto an iron surface partially covered by KCl, where deuterium selectively adsorbs onto the iron. This revealed that the first monolayer is complete after the deposition of 40 Å of KCl and that the first-layer KCl film coverage _KCl ⁽¹⁾ is given by _KCl ⁽¹⁾ = 1 - exp(-0.39±0.02t), where t is the film thickness. XPS data suggest that heating a KCl film to 550 K causes it to wet the surface. This leads to decreases in the friction coefficients for thin KCl films in accord with the idea that friction is reduced by the first monolayer of KCl on iron. Temperature-programmed desorption data indicate that KCl in the first monolayer is 5 kJ/mol more stable than the multilayer consistent with the wetting behavior. Finally, the kinetic data are analyzed to suggest that the first-layer film is 2.6 Å thick.     

A Vacuum Feedthrough Insulator at a Voltage of ∼1 MV

The design and results of tests of a vacuum feedthrough insulator for a pulsed electron accelerator with a voltage of 1 MV, a current of 20 kA, and a half-height voltage-pulse duration of 400 ns are presented. A method for distributing the voltage over the sections of the insulator due to an electron emission from specially created surfaces is proposed.     

An Aerogel Threshold Cerenkov Counter

The results of a study of the properties of aerogel manufactured at the Laboratory of Nuclear Problems, Joint Institute for Nuclear Research, are presented. The technology of the production of aerogel samples and the optical characteristics of these samples are briefly described. A formula relating the refractive index of the aerogel to its density with regard to the dispersion of light is analyzed. The results of testing of an aerogel threshold Cerenkov counter are presented. Testing was performed using a beam of charged particles with momenta p ranging from p = 0.4–2.5 GeV/. The efficiency of pion detection with p 1 GeV/ was 97%; the efficiency of proton detection with p 2.5 GeV/c, 4%.     

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.