Review of Scientific Instruments
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Quantitative mapping of switching behavior in piezoresponse force microscopy The application of ferroelectric materials for nonvolatile memory and ferroelectric data storage necessitates quantitative studies of local switching characteristics and their relationship to material microstructure and defects. Switching spectroscopy piezoresponse force microscopy (SS-PFM) is developed as a quantitative tool for real-space imaging of imprint, coercive bias, remanent and saturation responses, and domain nucleation voltage on the nanoscale. Examples of SS-PFM implementation, data analysis, and data visualization are presented for epitaxial lead zirconate titanate (PZT) thin films and polycrystalline PZT ceramics. Several common artifacts related to the measurement method, environmental factors, and instrument settings are analyzed.
Review of Scientific Instruments - Tập 77 Số 7 - 2006
Radiation resistance of elastomeric O-rings in mixed neutron and gamma fields: Testing methodology and experimental results Materials and components employed in the presence of intense neutron and gamma fields are expected to absorb high dose levels that may induce deep modifications of their physical and mechanical properties, possibly causing loss of their function. A protocol for irradiating elastomeric materials in reactor mixed neutron and gamma fields and for testing the evolution of their main mechanical and physical properties with absorbed dose has been developed. Four elastomeric compounds used for vacuum O-rings, one fluoroelastomer polymer (FPM) based and three ethylene propylene diene monomer rubber (EPDM) based, presently available on the market have been selected for the test. One EPDM is rated as radiation resistant in gamma fields, while the other elastomers are general purpose products. Particular care has been devoted to dosimetry calculations, since absorbed dose in neutron fields, unlike pure gamma fields, is strongly dependent on the material composition and, in particular, on the hydrogen content. The products have been tested up to about 2 MGy absorbed dose. The FPM based elastomer, in spite of its lower dose absorption in fast neutron fields, features the largest variations of properties, with a dramatic increase in stiffness and brittleness. Out of the three EPDM based compounds, one shows large and rapid changes in the main mechanical properties, whereas the other two feature more stable behaviors. The performance of the EPDM rated as radiation resistant in pure gamma fields does not appear significantly better than that of the standard product. The predictive capability of the accelerated irradiation tests performed as well as the applicable concepts of threshold of radiation damage is discussed in view of the use of the examined products in the selective production of exotic species facility, now under construction at the Legnaro National Laboratories of the Italian Istituto Nazionale di Fisica Nucleare. It results that a careful account of dose rate effects and oxygen penetration in the material, both during test irradiations and in operating conditions, is needed to obtain reliable predictions.
Review of Scientific Instruments - Tập 88 Số 11 - 2017
Commissioning and performance of the variable line spacing plane grating monochromator beamline at the Canadian Light Source The variable line spacing plane grating monochromator beamline at the Canadian Light Source (CLS) employs three grazing incidence variable line spacing gratings to cover a photon energy range of 5–250eV. It uses a 185mm period length planar permanent magnet insertion device as the photon source, sharing a straight section with another soft x-ray beamline at the CLS. The commissioning and performance of the beamline is reported. The high resolution photoabsorption spectra of Ar and PF5 gases are reported. A resolving power of over 40 000 for photons in the low energy region and >10000 for a wider energy range (8–200eV) can be achieved. A photon flux of up to 2×1012photons∕sper100mA with slit settings of 50μm has been measured.
Review of Scientific Instruments - Tập 78 Số 8 - 2007
Corona excited supersonic expansion
Review of Scientific Instruments - Tập 57 Số 9 - Trang 2274-2277 - 1986
Some High-Pressure, High-Temperature Apparatus Design Considerations: Equipment for Use at 100 000 Atmospheres and 3000°C Three items of equipment are described in detail; (1) A simple-piston and cylinder device capable of generating pressures to 50 000 atmospheres simultaneously with temperatures of 5000°C, (2) a tetrahedral-anvil device that has been successfully tested at 100 000 atmospheres and 3000°C, and (3) a stepped-piston device capable of developing pressures to 200 000 atmospheres at room temperature.
In addition consideration is given to such problems as (a) geometrical elements of design, (b) higher strength materials, (c) use of mechanical anisotropy in design, (d) electrical leads, (e) thermal and electrical insulation, (f) solid pressure transmitting media, (g) binding rings, (h) internal generation of pressure, (i) multistaging, and (j) calibration.
Review of Scientific Instruments - Tập 29 Số 4 - Trang 267-275 - 1958
Ultra-High-Pressure, High-Temperature Apparatus: the ``Belt'' Equipment is described for maintaining pressures of 100 000 atmos at temperatures in excess of 2000°C for long periods of time. The equipment makes use of conical Carboloy pistons that push into each end of a specially shaped Carboloy chamber. Both chamber and pistons receive lateral support from stressed binding rings. Axial motion of the conical pistons in and out of the chamber is accomplished (while still maintaining a pressure seal) by the use of a specially shaped sandwich gasket made up of naturally occurring pyrophyllite and a steel cone. The arrangement gives a multistaging effect in a single stage. Pyrophyllite in addition to its use in the gasket is also used as pressure transmitting medium, thermal insulation, and electrical insulation. The sample is heated by passage of an electric current through a metal or graphite tube. Methods of pressure and temperature calibration as well as construction details are discussed.
Review of Scientific Instruments - Tập 31 Số 2 - Trang 125-131 - 1960
Use of optimal estimation theory, in particular the Kalman filter, in data analysis and signal processing The Kalman filter, a powerful and useful optimal estimation technique, does not seem to be widely known among physicists. Here we outline the derivation of the algorithm, and give three examples of its use: (a) in estimating the value of a constant, with both system and measurement noise, (b) in numerical differentiation of noisy data, and (c) in optimally estimating the amplitude of a signal with arbitrary but known time dependence superimposed on a noisy background.
Review of Scientific Instruments - Tập 57 Số 11 - Trang 2862-2869 - 1986
A compact fluorescence polarization analyzer with high-transmittance liquid crystal layer Fluorescence polarization (FP) offers easy operation and rapid processing, making it implementable in molecular interaction analysis. Previously we have developed a unique FP measurement system using a liquid crystal (LC) layer and an image sensor. The system is based on a principle of synchronized detection between the switching rate of the LC layer and the sampling rate of the CCD. The FP system realized simultaneous multiple sample detection; however, the measurement precision was lower than that of the conventional FP apparatus. The main drawbacks were low light transmittance of the LC layer and insufficient synchronization between the LC layer and CCD. In this paper, we developed a new FP analyzer based on LC-CCD synchronization detection. By using a newly designed LC with high transmittance and improving synchronization, the performance of the system has been dramatically improved. Additionally, we reduced the cost by using an inexpensive CCD and an LED as the excitation source. Simultaneous FP immunoassay of multiple samples of prostaglandin E2 was performed. The error rate of the FP system is reduced from 16.9% to 3.9%, as comparable to the commercial conventional FP system.
Review of Scientific Instruments - Tập 89 Số 2 - 2018
Large-aperture TV detector with a beryllium-windowed image intensifier for x-ray diffraction A large-aperture (150 mm and 230 mm in diameter) x-ray TV-type detector has been developed for x-ray diffraction with synchrotron radiation. The detector consists of a beryllium-windowed x-ray image intensifier, an optical lens, a charge coupled device (CCD) image sensor, and data acquisition system. The spatial resolution is 270 μm(FWHM), and the dynamic range is 6000:1. The noise level is quantum limited. The nonuniformity of response and image distortion is corrected by software. When a TV-rate (NTSC-mode) CCD is used as an image sensor, time-resolved measurements with a rate of 30 frame/s can be achieved with its noise quantum limited.
Review of Scientific Instruments - Tập 66 Số 2 - Trang 2290-2294 - 1995
Fizeau interferometer for phase shifting interferometry in ultrahigh vacuum We describe a phase shifting interferometer which is based on a frequency-tunable diode laser in a Littrow configuration and is suitable for operation in ultrahigh vacuum. A wave front distortion measurement of a thin glass plate with a repeatability of λ/1000 is presented.
Review of Scientific Instruments - Tập 72 Số 9 - Trang 3726-3727 - 2001
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