Use Of Lamps Research Articles

A Modified Version of the Grimm's Glow Discharge Lamp for Use as a Demountable Hollow Cathode Emission Source. I. Construction Details

Abstract A commercially available hollow cathode emission source is modified in order to improve its applicability. Its main advantages consist in the practical prevention of short circuits, variable distances between cathode and anode, and the possibility of visual observation of the discharge. The lamp was satisfactorily tested with aluminium, copper and graphite cathodes.

A Modified Version of the Grimm's Glow Discharge Lamp for Use as a Demountable Hollow Cathode Emission Source. III. Blackening as a Function of Discharge Parameters

Abstract The influence of anode distance from hollow cathode on the blackening∗ of spectral lines excited by means of the modified Grimm's lamp was investigated for three representative cathodic materials, i.e. aluminium, copper and graphite using argon as the carrier gas. On the basis of the experimental results as well as voltage-current characteristic curves at distances of 7, 15, 20, 25 and 33 mm, it was possible to conclude that the optimal sets of discharge parameters for all the materials investigated are based on an electrode distance of 20-25 mm. In the case of copper a distance of 33 mm was also found to be highly suitable. An increase in the emission of copper lines at the largest anodic length with increasing pressure of the noble gas was also observed, in contrast with the behavior of the same element at shorter distances. A tentative interpretation of the phenomenon is given.

Continuous discharge Penning source with emission lines between 50 Å and 300 Å

We have developed a modified Penning discharge lamp for use in the soft x-ray and extreme uv spectral regions. The source produces a number of intense lines in the 50-300-A range and can be operated for substantial periods of time at high output levels before refurbishment is required. Refurbishment of this source, when required, is very easily effected.

Preparation and operation of selenium electrodeless discharge lamps for use in atomic-fluorescence flame spectrometry

Preparation and operation of selenium electrodeless discharge lamps for use in atomic-fluorescence flame spectrometry

Reproducible method for the preparation and operation of microwave-excited electrodeless discharge lamps for use in atomic-fluorescence spectrometry. Additional experience with cadmium lamps

Results are presented of experience with a previously reported method for the preparation and operation of cadmium microwave-excited electrodeless discharge lamps. The method can be used while employing alternative microwave-excitation equipment but it is necessary to alter the levels of the factors that control the preparation and operation of the lamps. Lamps of identical performance are produced with the alternative equipment. A mean atomic-fluorescence detection limit of 0.07 µg l–1 with a relative standard deviation of 25% was achieved for 12 cadmium lamps prepared in two batches of six with a time interval of 4 months between them.

Determination of the line shapes of atomic nitrogen resonance lines by magnetic scans

A technique is given for calibrating an atomic nitrogen resonance lamp for use in determining column densities of atoms in specific states. A discharge lamp emitting the NI multiplets at 1200 A and 1493 A is studied by obtaining absorption by atoms in a magnetic field (0-2.5 T). This magnetic scanning technique enables the determination of the absorbing atom column density, and an empirical curve of growth is obtained because the atomic f-value is known. Thus, the calibrated lamp can be used in the determination of atomic column densities.

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.

Some Characteristics of a Pulsed Xenon Lamp for Use as a Light Source in Kinetic Spectrophotometry

This paper presents details of the electrical and optical characteristics of Osram XBO 250, 14 V, 18 A, high pressure xenon arc lamps during 1 msec current pulses of several hundred amperes which are used as analyzing light sources in kinetic spectrophotometry. The lamps are operated continuously at their normal rating between pulses and the arc provides a path of high electrical conductivity for the pulse current. As a result the volume occupied by the discharge and the potential drop between the electrodes do not change very much during a pulse, whereas the radiance of the discharge increases by a large factor which depends on current and wavelength. At 450 A the increase in radiance is about 700× in the far ultraviolet, about 300× in the visible, and about 50× in the infrared. XBO 250 lamps operated in this way can withstand many thousands of pulses without excessive deterioration. A circuit for producing the current pulses is described.

Electronic modulation of microwave-excited electrodeless discharge lamps for use in atomic-fluorescence spectrometry

Electronic modulation of electrodeless discharge lamps has been investigated with respect to frequency of operation and modulation waveform. The optimal frequency of operation was found to be ca. 20,000 Hz, using a square waveform, and modulation was best achieved by adding the modulation waveform to the reference of the stabilizing element in the microwave power supply. Optimal operating conditions have been established for d.c. and a.c. modes of operation for several sources.

Self-modulated spectral calibration lamps for use with lock-in amplifier systems

The majority of gas discharge spectral calibration lamps are run from the 'mains' in series with an appropriate inductor. The intensity output from these lamps consists primarily of a 100 Hz component which has a certain phase lag with respect to the mains. In many laboratory spectrometers the signal from the photomultiplier or photoconductive detector is recovered using a lock-in amplifier (phase-sensitive detector). A circuit is described which provides a suitable variable phase 100 Hz reference signal for the lock-in amplifier system when a calibration lamp is being used. It is shown that this method of extracting the signal is just as sensitive as that using an additional mechanical modulator (chopper), and has a number of advantages.

A Comparison of Lamps for Use in High Continuous Power Nd:YAG Lasers

The efficiency of krypton, xenon, and tungsten-iodine lamps for pumping Nd: YAG are compared both spectroscopically and by laser pumping. The relative pumping efficiencies of xenon and tungsten to krypton are 0.86 and 1.1, respectively. However, because the tungsten filament uses a higher percentage of its power in overcoming the laser threshold, the krypton lamp with its larger power density yielded the best over-all efficiency. An output power of 105 W was obtained at an input power of 3610 W for an over-all efficiency of 2.9%.

Hollow-Cathode Lamp for Use in Emission and Absorption

Demountable hollow-cathode lamps have frequent application as sample emission sources in high resolution spectroscopy1,2 and as light emission sources in atomic absorption spectrometry.3,4 We are interested in both of these uses and also the application of the lamps for the sample absorption sources in atomic absorption spectrometry.

Improvements in a Source for Use in the Vacuum Ultraviolet*

An improved version of a low-pressure hot cathode discharge lamp for use in the vacuum ultraviolet is described. It has been used with hydrogen, helium, argon, and nitrogen to furnish line radiation from below 500 A to about 1650 A and continuum radiation from hydrogen from 1650 A to 3500 A. The lamp operates at low voltages, is reliable, and simple to rejuvenate when the output becomes low. Figures are given on its output as seen through a specific monochromator.

Improved, Single Flash, Continuum Source for Use below 2000 A*

A high-intensity, low-energy flash lamp for use below 2000 A is described. The radiation from a single flash, at 4000 v and 15 mfd, produces an emission continuum to 1500 A which is of sufficient intensity to be used with either photographic or photomultiplier techniques. A densitometer trace of the Schumann-Runge O2 absorption band system is shown. Also, oscilloscope traces are presented which were taken at 1700 A. These show attenuation of the signal as a function of oxygen concentration.

A simple 500 Mc/s oscillator for use with electrodeless mercury-198 lamps

The oscillator, simply adjustable in frequency from 300 to 500 Mc/s, consists of a parallel line resonator associated with a double triode developed for mobile transmitters. It is intended for the excitation of electrodeless mercury-198 lamps for use in interferometry.

The Seasoning of Tungsten Filament Incandescent Lamps for Use as Photometric Standards

The rate of seasoning of gas-filled and vacuum tungsten lamps is consistent with the view that recrystallisation of the tungsten filament is the main process involved. The changes during seasoning indicate a decrease in emissivity of the filament which is largely non-selective with regard to wave-length. Seasoning at a relatively low colour temperature almost completely stabilises standard lamps for operation at higher temperatures, and has the advantages of producing less blackening on the envelope and expending less of the useful life of the lamp.

Improved Hydrogen Discharge Lamp for Use in Refractometry

Improved Hydrogen Discharge Lamp for Use in Refractometry

An ophthalmoscope for use in operations.

IT IS generally recognized that ophthalmoscopic control is a sine qua non for the surgical repair of retinal detachment. Both the direct and the indirect technics as usually practiced have well known disadvantages in the theater—loss of time with either method, danger of sepsis with the former. The apparatus to be described was first devised for the removal of a cysticercus from the vitreous. 1 Its application to the surgical treatment of other conditions followed automatically. A head lamp for use in operations, like that commonly used by otolaryngologists, was fitted with a perforated mirror so that it was possible to look through the hole in the mirror along the axis of the reflected beam of light, as with an ophthalmoscope (fig. 1). It was subsequently found that a similar suitable apparatus is available commercially. 2 A pair of + 4.0 D. sph. spectacles is worn. The upper and lower segments

A Steady Mercury Lamp for Use in Research

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A candle lamp for use during action

A candle lamp for use during action