Deflection Signal Research Articles

An approach to the infrared study of materials by photothermal beam deflection spectroscopy

Infrared Fourier transform photothermal beam deflection spectroscopy (PBDS) is briefly outlined. It involves heating a surface by the photothermal effect, using infrared (IR) radiation from a scanning interferometer; energy is transferred to the gas above the surface and the resulting refractive index gradient in the gas is detected by observing the deflection of a laser beam grazing the solid's surface; the deflection is related to the IR radiation which is absorbed, so that the Fourier transform of the deflection signal results in the IR spectrum. PBDS is especially useful for materials which scatter and/or absorb IR radiation so extensively that conventional transmission/absorption techniques are not possible. A variety of examples of applications are given, including spectra of polymers, floor tile, polyester thread and fabric, leather, cellulose, paper, lichen and bone.

Fast and accurate electron‐beam deflection circuits using two kinds of D‐A converters

AbstractThis paper presents results of the investigation on the characteristics of the electron‐beam deflection circuit which utilizes a fast D‐A converter and a high‐resolution D‐A converter. The scanning rate depends on glitches of the fast D‐A converter. The setting time calculated by the first‐order approximation model agrees well with the measured result. If the newly proposed deglitching circuit was used, the glitches were reduced to below 10% and the settling time for ±0.0004% was 0.7 μs. The deflection signal stability depends on the high‐resolution D‐A converter. The short‐term stability was ±1 ppm/10 hours without temperature compensation. The long‐term stability with temperature compensation was ±3 ppm/1 month.

Low profile electron collector system

The design of the exposure region of an Electron-Beam Microfabrication System is usually a compromise between beam formation, deflection, and registration signal collection. In systems where a post final lens deflection assembly is used, this region is inevitably restricted in space and access for signal collection becomes difficult. Annular planar detectors of the silicon semiconductor diode type have been used in these situations but are restricted in their range of electron energy response and noise performance. An attractive alternative is the channel plate electron multiplier which can be configured into a compact annular assembly with low profile (6 mm). Additionally, it is sensitive to low energy secondary, and high energy backscattered electrons and can be made selectively sensitive to the higher energy electrons alone by suitable biasing. In the design implementation described, an annular channel plate is provided with a signal collection plate and electronic drive scheme to decouple the output signal from the relative high bias potential needed on the plate. The system has proved useful in viewing a variety of registration features in the EBMF 2 Microfabricator ranging from high contrast metallic marks used in drift correction to low contrast etch pits in silicon covered with electron resist for direct slice writing.

Time-resolved scalar measurements in a confined turbulent premixed flame

Measurements of power spectral density and probability density function of related scalar properiteis—density gradient, temperature and positive ion current—in a confined turbulent pre-mixed propane-air flame are reported. The techniques employed comprise quantitative laser schlieren, a water-cooled Langmuir probe and an exposed-bead thermocouple, compensated electrically for the effects of thermal inertia. The comparatively large-scale, ordered structures in the flowfield, evident from instantaneous schlieren photographs, are investigated by cross-correlation of simultaneous laser deflection signals measured at different axial positions. The several techniques are compared in terms of the particular insight which they each afford and their inherent performance. Comparison with expectation from simple theoretical models, based on thin-flame descriptions of the instantaneous turbulent field, whilst presenting a broad measure of agreement, highlight ambiguities in the interpretation of the relationship between positive ion current and temperature.

A Jumbo for Vertical Deflection and Video Signal Processing Circuits in TV Receiver

A monolithic single chip IC for TV vertical deflection and video signal processing circuits has been successfully developed. The IC incorporates video pre-amplifier, noise canceller, sync separator, horizontal AFC, horizontal oscillator, vertical integrator, vertical oscillator and vertical deflection amplifier with vertical output stage. The 118 ×114 mil chip, containing 107 transistors, 25 diodes, 157 resistors and 4 capacitors, is sealed in a 24 pin dual-in-line power package. The allowable maximum power dissipation of this IC is 2.1 watts at an ambient temperature of 70 °C, therefore this IC can be used in a 12" B/W TV receiver without an additional heat sink.

試作マイクロバランスにおける微小重量変化の検出

With objection of absolute measurement of sputtering yield, the microbalance has been constructed. In the balance system, weight change was followed from observation of the deflection of the balance. The deflection was optically magnified and was converted to electrical output by means of a linear photopotentiometer. To the weaker deflection signal due to smaller weight change than the noise, separation of the signal from the noise was an important problem. Of the noises, the fluctuating noises were induced from 1) propagation of mechanical vibration (1070 Hz) to the balance and the optical alignment, and 2) propagation of sample oscillation to the balance (1Hz), and periodical thermal expansion or shrink of the optical alignment in the thermostatic room (0.02 Hz). The amplitude of fluctuating noises having higher frequency components than 1 Hz could be damped by a factor of 5 by the use of a low pass filter (cutoff frequency is 0.1 Hz). Then the amplifier gain to the deflection signal could be increased by a factor of 5. As a result of the improvement of S/N, the increase of the sensitivity from 5×10-7 g/mV to 7.3×10-8 g/mV was achieved. The minimum detectable weight change per hour was also reduced from 10-6 g/hr to 3.7×10-8 g/hr.

Radiation damage mechanisms in some organic molecular crystals

Since the relative intensities of electron diffraction spots are a very sensitive measure of the long range order within a crystal, we have designed and built a digital Scanning electron diffractometer to record them as irradiation proceeds. This system is connected to a JEOL JEM 100C electron microscope and generates deflection signals which tilt the illumination incident on the specimen, causing the electron diffraction pattern to be scanned across a scintillator-photomultiplier assembly located below the microscope. The signals are digital, so that the scan consists of a series of discrete steps, with variable but accurately controlled time intervals between. In this work it has been found most convenient to scan along a single row of diffraction spots. To this end the step size is set so that after each step either a spot or an intermediate continuous background region is coincident with the optic axis. During the time interval between steps the detector output (proportional to the current in the spot) is integrated, digitised, and stored in a solid state memory prior to output to the computer for analysis.

Technique for a contour display of photoemission uniformity

A contour plotter has been designed to display the sensitivity uniformity of photocathodes in quantized format on the Z axis of an oscilloscope. An optical scanner, synchronously driven by the oscilloscope X-Y deflection signals is used to raster scan the photocathode with a focused light beam. Sensitivity, resolution, and scanning time are sufficient to use the plotter to monitor sequential processing steps for photocathodes in demountable, ultrahigh vacuum systems. A general description of the contour plotter system and a detailed circuit description are given. An example relating to cesium uniformity on a III-V photocathode is presented to illustrate the use of the contour plotter.

Computer Controlled Pattern Generating System for use with Electron-Beam Writing Instruments

Recent advances in electron sources and electron resists have resulted in a significant increase in potential exposure rate in electron-beam writing instruments. This in turn places stringent requirements on the pattern generating electronics which must be fast enough to avoid their limiting potential system throughout, yet flexible enough to be capable of creating all normally required geometries. A computer-controlled pattern generation system is described which is designed to meet these requirements. In this system, the speed limitation due to the calculation and data-transfer rate of modern minicomputers is avoided by the use of an auxiliary special-purpose logic processor. Patterns are built up from a basic trapezoid shape with two sides parallel to rectangular cartesian coordinate axes. The computer has only to specify the basic parameters defining a trapezoid and the auxiliary processor will then output coordinates representing the end points of lines defining the figure in a raster-scan format. These coordinates, which may be generated at rates up to 1 MHz are passed to a pair of precision ramp generators. The ramp generators, which are based on commercially available 16-bit digital-to-analog converters, then produce the analog deflection signals needed to define the line, at a sweep rate which may be varied under computer control over six orders-of-magnitude. Particular care has been taken to reduce the switching spikes, inherent in digital-to-analog converters, to negligible proportions on the output waveform.

The cumulative interaction of finite amplitude waves in strings

A “two time scale” asymptotic expansion procedure describing the modulation of a propagating simple wave governed by a system of non-linear partial differential equations is applied to the deflection waves of non-linear elastic strings. Rapid deflection signals propagating into a general slowly varying disturbance are modulated. In addition, they themselves affect the equations for that disturbance. The two effects are separated naturally when, to prevent the cumulative growth inherent in most “high frequency” procedures, an averaging technique is introduced. The interaction of two deflection waves is given as a specific example.

Early Scanning Electron Microscopy

The transmission electron microscope can be traced back to the work of K. Knoll and E. Ruska in Berlin who succeeded in 1931 in demonstrating a two lens electron microscope. The scanning electron microscope may also be traced back to the work of M. Knoll in 1935, during a study of secondary electron emission from surfaces. Two cathode ray tubes were used with a time-base generator supplying deflection signals to both tubes at once. The specimen under test was sealed into the first tube and the electron beam from the gun was scanned across the specimen surface and the variations in specimen current formed the signal. This signal was used to modulate the grid of the second cathode ray tube and the image displayed gave the variation in secondary emission on the specimen surface. In one case the word “Stuggart” was shown.

Cathode-Ray Oscilloscope Intensity Modulator

An electronic system is described for modulating the beam intensity of a cathode-ray oscilloscope in such a manner as to reduce variations in trace brightness due to differences in writing speed. A voltage derived by a push-pull differentiating amplifier from the vertical deflection signal is added to the instrument's intensity-control voltage. By use of this system, improved photographs of wave forms can be obtained.