Use Of Light Source Research Articles

Beta-induced luminescence of some crystalline inorganic materials

The beta-particle-induced luminescence spectra of a number of crystalline solids have been recorded using a single-photon-counting spectrometer in the search for high-stability u.v. light sources for use in analytical instrumentation. Of particular interest are the emissions from CaF2, sapphire and spinel, all of which produce useful emission intensities below 300 nm. The kinetic behaviour of the emissions from 1 : 1 and 1.8 :1 spinels have been studied in some detail, and it is found that the noise level of the emitted light is significantly reduced by the ‘smoothing’ action of a long luminescence decay time. The results are consistent with the view that the spinel emission is associated with the recombination of electrons trapped on [AL]+Mg with holes trapped on [Mg]–Al centres.

0.81 μm band AlGaAs/GaAs double-channel planar buried-heterostructure laser with large optical cavity

0.81 μm-band AlGaAs/GaAs double-channel planar buried-heterostructure laser diodes with large optical cavity have been developed as light sources for use in analogue optical fibre communication systems. Linear light-output/current characteristics and a single-longitudinal-mode spectrum at a modulation frequency f = 100 MHz with modulation index m = 0.9 have been attained.

The resultant dispersion of fiberguide link

The mathematical separation of multimode dispersion and material dispersion on the overall dispersion of an optical fiber will be shown in this letter. The relations derived can be used to evaluate the resultant baseband frequency response of a fiberguide with the use of light sources of various spectral bandwidth. The approximate description of the baseband frequency response characteristics of individual fiber sections permits one to estimate the resultant transmission bandwidth of the fiberguide line.

同軸型放電管励起色素レーザの動作特性

This paper reports simple coaxial flashlamp-excited dye lasers developed and fabricated high power, frequency tunable light sources for use in a variety of spectroscopy and optical instrumentation systems such as laser radars and remote sensors. Optimum design parameters of the discharge tube length and the annular width are obtained. The operational performances used as a dye laser oscillator and an amplifier are investigated using Rhodamine 6G in ethanol and pure water-Ammonyx LO solvents. In the oscillator mode of operation, maximum output energy of about 400 mJ and energy conversion efficiency of 0.12% are realized. In the amplifier mode, effective output gain of 120 is measured and a stable synchronization of the flashlamp discharge with the oscillator laser is attained by utilizing simmer discharge technique. Higher pulse repetition rate and smaller laser beam divergence are possible by using pure water as a dye solvent than ethanol. No remarkable output degradation of the coaxial flashlamp is observed in excess of 1000 shots at 300J input energy.

An evaluation of fluorescent light sources for use in phototherapy of neonatal jaundice.

An evaluation of fluorescent lamps for use in the phototherapy of neonatal jaundice was undertaken by making spectral irradiance measurements of each lamp. Conclusions are drawn on the usefulness of current methods of measuring exposure dose to radiation from the lamps. UV hazards from the lamps are evaluated.

Isotope shift and hyperfine structure in the atomic spectrum of tin

Three lines in the atomic spectrum of tin, λ 3262 Å, λ 3283 Å and λ 6454Å have been studied in emission under high resolution with the use of light sources containing enriched isotopic samples. Results are reported for isotope shifts in these lines for the abundant stable isotopes ( A ≽ 116). Pressure-scanned Fabry–Perot etalons provided the necessary resolution; the spectrograms for λ 6454 Å were recorded and analysed by digital techniques, and for this line hyperfine structure constants required in the interpretation of the data were also evaluated. The results for the three lines are not in good agreement with earlier work, but are shown to be self-consistent by means of a King plot. Their interpretation in terms of the nuclear charge distribution is considered in the following paper.

Light Output Control of a Pulsed Light Source for Use in Stabilizing Scintillation Detectors

A method is described for controlling the light output of a pulsed light source so that a scintillation detector stabilizing system based on the pulsed light source would be able to compensate variations in the light output of the scintillator with temperature as well as other temperature dependent instabilities.

A Simple Multiple Spark System

A simple multiple spark system is described. This spark system was used to provide two spark discharge light sources for use with Schlieren photography. The spark durations were such that shock waves with velocities up to 520 m/sec could be satisfactorily photographed.

Lighting for colour television

Colour television presents a considerable challenge to the studio lighting director. Among other things he must provide high levels of illumination, be able to adjust intensity over a considerable range without causing unacceptable changes in colour rendering and help to maintain high productivity from the studios. The BBC has encouraged the development of improved light sources for use in a new range of studio luminaires. In addition, the latest studio has been equipped with a lighting control system employing computer techniques which enables 100 different combinations of intensity information to be stored and recalled immediately. Among problems which are still to be solved are the production of colour filters able to operate continuously at high temperatures and the development of new high intensity light sources for use in follow-spots and in the production of clouds and other lighting effects.

A Vacuum Spark Light Source for the Extreme Ultraviolet Region

A mechanically triggered spark light source for use in the extreme uv region is described. The source is designed for precise optical placement of the spark and for compatibility with clean ultrahigh vacuum systems. The performance of this source is compared with that of a light source generated by a laser-produced metal plasma. The effect of magnetic confinement of ionic species in the spark is evident in the comparison of the spectra of the spark and the laser-produced plasma.

Arc Jet Excitation Source

A high-temperature light source for use as a spectroscopic excitation source has been developed. Solution samples are injected into a high velocity stream of plasma which is formed by an A-He are burning between a nozzle-shaped anode of copper and a cathode of thoriated tungsten. Electrode erosion, which disturbs the discharge, is eliminated by introducing the sample in such a manner that it contacts neither with the cathode foot of the arc, which is formed on the tip of the negative electrode, nor with the anode foot, which is formed on the inner surface of the nozzle. The discharge is further stabilized by preventing the arc from wandering within the throat of the nozzle by means of an electromagnetic force. Flame temperature of 11,500°K is measured when the arc is operated at 300 amp, power into the arc being 7 kw. Spectral lines originating from upper energy-levels up to 13 eV, such as those of hydrogen, carbon, phosphorus, oxygen, and zinc have been observed.

Arc Jet Excitation Source

A high-temperature light source for use as a spectroscopic excitation source has been developed. Solution samples are injected into a high-velocity stream of plasma which is formed by an argonhelium arc burning between a nozzle-shaped anode of copper and a cathode of thoriated tungsten. Electrode erosion, which disturbs the discharge, is eliminated by introducing the sample in such a manner that it contacts neither with the cathode foot of the arc on the tip of the negative electrode, nor with the anode foot of the arc on the inner surface of the nozzle.The discharge is further stabilized by preventing the arc from wandering within the throat of the nozzle by means of an electromagnetic force.Flame temperature of 11, 500°K has been measured for an arc current of 300 amp.Spectral lines originating from upper energy-levels up to 13eV, such as those of hydrogen, carbon, phosphorus, oxygen, and zinc have been observed.

A Microwave-Powered Hydrogen Lamp for Vacuum Ultraviolet Photochemical Research

An intense hydrogen light source for use in photochemistry is described, which yields intensities of up to 1016 quanta/sec in the 1100–1850 Å spectral region. Intensity measurements were made employing the photochemical formation of ozone in a flow of oxygen and the photoelectric volume effect in a nickel cathode. The intensity distribution was obtained mainly from spectrometric work. Typical observed intensities were 3 × 1015 quanta/sec in the 1400–1650 Å region and 3 × 1015 quanta/sec for Lyman-alpha at 1216 Å. Under the influence of the discharge the transmittance of LiF windows gradually decreases; however, the percentage decrease is a well-reproducible function of time.

Two Light Sources for Use in the Extreme Ultraviolet

Two light sources, one a capillary discharge tube and the other a hollow cathode discharge tube, for use in the extreme ultraviolet are described. Both tubes are rugged, easily demountable, and electrically quiet so that counting techniques can be used. Results are given for resonance lines of H, A, Ne, and He; the He2 molecular continuum; and lines of singly ionized A, Ne, and He. The wavelength region examined lies between 1216 and 256 Å.

The medical use of light sources.

The medical use of light sources.

A Mercury Light Source for Use with a Diffraction Grating

A Mercury Light Source for Use with a Diffraction Grating

A telephotometer employing the maxwellian view principle and its use in measuring atmospheric transmission

The paper describes a Maxwellian View type of telephotometer designed for measurements of atmospheric transmission. The accuracy of measurements obtained with this instrument compares favourably with that given by other methods of measurement. Over distances up to 8000 ft. the instrument does not require the use of light sources of great intensity. The telephotometer and its accessory apparatus are readily transportable. In using the instrument care must be taken to avoid error due to the Stiles-Crawford effect; but provided this and other sources of systematic error are avoided, the error in determining atmospheric transmission should not, under favourable conditions, exceed 5 per cent.

Studies of destructive light sources for use in accelerated weathering systems

Studies of destructive light sources for use in accelerated weathering systems