A setup for studying rare decays of heavy and superheavy elements

A new setup composed of 32 pairs of semiconductor detectors, systems of data acquisition, storage, and processing, and a vacuum system has been developed at the Flerov Laboratory of Nuclear Reactions of the Joint Institute for Nuclear Research. The setup can be used for low-background measurements and is intended to study radioactive decays of relatively long-lived isotopes of heavy and superheavy elements in a geometry close to 4π.     

Experimental setup for studying dynamics of the calcium interaction in cells

A calcium cell signaling system is one of the first, which were formed in the course of evolution of systems. The understanding of calcium binding–uncaging dynamics is crucial in studies of corresponding intracellular processes. By now, a great number of calcium-dependent processes have been investigated. However, works that fully consider these processes are absent. This is specified in many respects by the instrumental abilities. In this work, requirements for the experimental setup intended for comprehensive studies of calcium interaction dynamics are briefly formulated, its block diagram is described, and the results of test experiments are presented.     

Use of ion beam techniques for studying the leaching properties of lead implanted silicates

Na and H depth profiling has been performed on samples of soda-lime glass and albite subjected to Pb ion implantation and leaching, by means of resonant nuclear reactions. Before leaching, the implanted albite samples show a particular Na depth profile with a marked depletion at the range of the incident Pb ions but an unchanged surface concentration. For soda-lime glass, a Na surface depletion has been noted, which increases with the ion dose. After leaching, the compositional change in albite is limited to the implanted layer, whereas in soda-lime glass it proceeds at much larger depths and exhibits a linear time dependence for short leach times. In addition Pb implantation is found to drastically increase H penetration in vitreous silica. Such ion induced effects are discussed with reference to the use of ion implantation to simulate internal irradiation due to α-decay.     

An automated setup for studying thin ferroelectric films by the thermal-noise method

Determination of the initial permittivity (the permittivity in a weak electric field—a field that is much lower than the coercive field) of thin ferroelectric films is the most important problem in studying such objects. For this purpose, the thermal-noise method is a convenient tool. In this case, in contrast to the bridge method, a measuring voltage that can create a significant field in a sample is not applied to it, but a thermalnoise voltage that depends on the film capacitance is measured across a load resistor, which is connected in parallel to the specimen. Below, an automated setup using the LabVIEW package is described. The technique was first applied to studying thin films. A significant difference between the results of measuring the permittivity of thin films by the bridge and thermal-noise methods has been revealed.     

MASHA separator on the heavy ion beam for determining masses and nuclear physical properties of isotopes of heavy and superheavy elements

The MASHA mass spectrometer designed for identifying superheavy elements by their masses is described. The separation efficiency has been measured in the autonomous mode using four calibrated leakages of noble gases. The total separation efficiency of the mass spectrometer with a hot catcher and an ion source based on the electron cyclotron resonance has been determined using the ⁴⁰Ar beam. Test experiments have been carried out, in which α-active Hg isotopes produced in complete fusion reaction ⁴⁰Ar + ¹⁴⁴Sm → ^{184 ? xn} Hg + xn, have been detected in the focal plane of the mass spectrometer. The separation time and efficiency have been determined for short-lived Hg isotopes.     

A setup for studying thermal characteristics of metals at high temperatures

A setup for studying the radiation characteristics of metals based on calorimetry of metals exposed to electron heating under high-vacuum conditions has been developed. A new design of the cathode-anode unit ensures a uniform distribution of the electron flow over the sample surface. The created decelerating field prevents secondary electrons from leaving the cathode-anode unit. The serviceability of the setup was tested via measurements of the integral hemispherical emissivity of extremely pure titanium (>99.91 mass %). The emissivity changes in the temperature range 1155–1165 K, associated with the restructuring of the crystal lattice from a close-packed hexagonal structure into a body-centered cubic structure, has been revealed.     

An experimental system for studying the dynamics of the pulsed subnanosecond electric breakdown of gas gaps

In order to study pulsed gas breakdown initiation dynamics, a subnanosecond voltage pulse with a width of 0.2–4 ns and a height of 20–150 kV is applied to a gas-discharge gap. The voltage rise rate ranges from 6×10¹³ to 7.5×10¹⁴ V/s. The amplitude and duration of subnanosecond high-voltage pulses are adjusted continuously, as well as the magnitude and profile of the discharge current. The glow accompanying prebreakdown and breakdown processes in the gap is registered by a high-speed electron-optical camera.     

The Oxford-Diamond In Situ Cell for studying chemical reactions using time-resolved X-ray diffraction

A versatile, infrared-heated, chemical reaction cell has been assembled and commissioned for the in situ study of a range of chemical syntheses using time-resolved energy-dispersive X-ray diffraction (EDXRD) on Beamline I12 at the Diamond Light Source. Specialized reactor configurations have been constructed to enable in situ EDXRD investigation of samples under non-ambient conditions. Chemical reactions can be studied using a range of sample vessels such as alumina crucibles, steel hydrothermal autoclaves, and glassy carbon tubes, at temperatures up to 1200 °C.     

A setup for studying the characteristics of 218Po transfer in air

An experimental setup and a technique for studying the characteristics of ²¹⁸Po transfer in air is described. The experimental technique is based on detecting α decays of ²¹⁸Po atoms that precipitate by diffusion on the surface of a semiconductor detector from a closed volume filled with air with an admixture of ²²²Rn. It is shown that, under conditions of electrostatic precipitation inside a radiometer chamber, a fraction of ²¹⁸Po atoms attach to coarse particles for which sedimentation may play an important role. The rates of attachment of free 218Po atoms to aerosols are obtained.     

A magneto-optical setup for studying the time evolution of nanoscale domain-wall displacements under pulsed magnetization

A magneto-optical setup for studying the time evolution of nanoscale domain-wall displacements of domain walls in magnetic films with a regular domain structure is described. Methods for spatial filtering of the output optical flux using the Fourier image of the domain structure and the impulse transient response in the real-time mode are applied in the setup. This allowed an increase in the sensitivity to domain-wall displacements of up to 5 nm and registration of their evolution with a temporal resolution of 1 ns.     

Testing a prototype of the charge-measuring system for the NUCLEON setup

While preparing for the NUCLEON experiment, a prototype of the experimental setup was tested on a beam of high-energy ions. The response of the charge-measuring system was investigated. The test experiment was simulated. The simulated charge distributions were compared to the experimental data.     

A setup for measurements of free-electron lifetime in a gas phase

A setup for measuring the lifetime of free electrons in a neutral buffer gas that contains an electronegative impurity is described. This setup is intended for prompt diagnostics of carcinogenicity of chemical compounds and consists of an ionization chamber with laser photoionization of the cathode, a gas system, and a system for collection and processing of experimental data based on an HBJI45 amplitude-to-digital converter. The techniques for preparing the tested gaseous mixtures and processing the experimental results are described. The results of measurements of the lifetimes and calculated free-electron capture constants for a CO₂ + O₂ calibrating mixture and mixtures of CO₂ with organic molecules are presented. The setup allows measurements of the lifetimes of free electrons in mixtures in the range 0.5–70 μs at measurement errors of 0.2–6%, respectively, and study of two or three potentially carcinogenic substances a week.     

An experimental setup for studying neutron-neutron final state interaction on the neutron channel of the Moscow Meson Factory

A setup for measuring the singlet nn-scattering length in the n + d → p + n + n reaction is described. It is composed of a neutron hodoscope with an angular aperture of 12° and a scintillation detector for protons escaping at an angle of 90° with the beam direction. The exit angles and the energies of a proton and both neutrons are measured. The neutron energies are measured using the time-of-flight method. At a time resolution of ∼0.6 ns and a flight base of ∼5.5 m, the accuracy in measuring the neutron energy is ∼1% at an energy of ∼15 MeV. The dependence of the reaction yield on the relative energy of two neutrons is investigated. The neutron-neutron final-state interaction manifests itself as a peak in this distribution.     

烟气排放连续监测系统的烟气参数在线监测技术

简要介绍了烟气排放连续监测系统的烟气参数监测项目及技术要求,包括炯气流速、烟气水分含量、烟气含氧量在线监测技术。对烟气参数在线监测的应用与发展进行了探讨。     

A data acquisition system of the FODS setup

A data acquisition system of the focusing double-arm spectrometer (FODS) setup is described. The information from each recording electronic module is read in response to each trigger by an ЛЭ-74 high-speed controller with a buffer memory and is transmitted by a PCI-7200 extension card to the computer memory at the end of the spill. All crates are read in parallel, ensuring a high speed of operation of the system (8000 events per spill for one spectrometer arm). The system is able to read data from different detectors (drift chambers, proportional chambers, calorimeters, Cherenkov radiation ring spectrometer, etc.), possesses a high flexibility, i.e., ensures readout of information for several types of triggers (inclusive, arm coincidence, two particles in one arm, etc.), and enables calibration of detectors in each spill. The software is based on the MIDAS project with an open initial code and allows one to control operation of all detectors during experiments.     

Production and quality control of optical elements for the end cap hadron calorimeter of the CMS setup

An end cap hadron calorimeter, in which scintillators with wavelength-shifting fibers are used as the active elements, has been designed for the compact muon spectrometer (CMS) now under construction at CERN. A total of 1368 optical elements containing 21 096 scintillators have already been manufactured. The production and quality control procedures for these optical elements are described.Translated from Pribory i Tekhnika Eksperimenta, No. 1, 2005, pp. 36–45.Original Russian Text Copyright ¢ 2004 by Abramov, Volkov, Goncharov, Zaichenko, Korablev, Korneev, Krinitsyn, Kryshkin, Markov, Talov, Turchanovich.     

带孔弹性元件温度场的模拟实验方法

在一些特殊应用场合,传感器弹性元件处于温度梯度场而产生热应力,实验研究温度场及热应力分布是采取补偿措施的前提和基础,本文介绍了带孔弹性元件温度场研究的模拟实验方法,并根据获得数据整理出温度分布随几何参数变化的部分拟合方程。     

Development of an experimental setup for microflow measurement using interferometry

The precise measurement of micro and nanoflow of incompressible liquids (below 1 μL/h) is a complex task due to several factors involved in, namely, evaporation, adsorption and the existence of air bubbles within the system. Nevertheless, the importance of its measurement is undeniable in equipment such as insulin pumps, or medical drug delivery devices for new-born, microchip flow pumps, to mention few.The work herein presented was developed in a partnership between the Volume and Flow Laboratory (LVC) of the Portuguese Institute of Quality (IPQ) and the Department of Mechanical and Industrial Engineering (DEMI) of The New University of Lisbon under the project MeDD II – Metrology for Drug Delivery. It had the main objective of conceiving a new Portuguese standard for the measurement of ultra-low flow using interferometry, with a target uncertainty of 1% (k = 2). Therefore, the new setup relies on an interferometer made up of a laser unit, two retroreflector cubes, one beam splitter, as well as a flow generator (a Nexus syringe pump) and a computer for data acquisition.Experimental tests on a Flow generator and a Coriolis flow meter were carried out at different flow rates. With the innovative methodology developed during the present research, it was possible to measure flow rates of an incompressible fluid (water) down to 1 μL/h with an uncertainty of 3% (k = 2).     

A device for studying the scattering properties of fluid droplet samples

Scattering indicatrices can yield substantial information on the composition and properties of samples in studies of dispersive media by optical methods. This paper describes a simple and convenient experimental setup that allows measurements of the scattering indicatrices (at angles from −90° to +90°) of fluid samples in the form of sessile droplets with concurrent recording and estimation of the geometrical parameters of the lateral projection of a droplet sample. The results of studying samples of blood with different levels of hematocrit and different types of erythrocyte aggregation are presented. The device can be used both in scientific research for studying physical properties of liquids and in clinical diagnostic practice for staging a number of existing hematological, immunological, and biochemical tests.     

Testing the electronic system for the γ-quantum detector of the SVD-2 setup

Firmware for checking the electronic equipment for recording signals of the hodoscope γ-quantum detector is described. The detector has 1344 channels for measuring charges of nanosecond pulses arriving from outputs of photomultiplier tubes. The testing system is intended to test the electronics at each level of its hierarchical structure and also to perform the initial check of the γ-quantum detector itself.