SU1677739A1 - High-intensity spectral lamp for atomic absorption and fluorescence - Google Patents

Abstract

The invention relates to spectral light sources for use in atomic absorption and atomic fluorescence spectrophotometers. The aim of the invention is to increase the intensity of the radiation of the resonant lines. The spectral high-intensity lamp contains a glass balloon 1, a flat window 2, a thermal cathode 5, a glow discharge cathode 6, an electrical insulating tube 11, and an anode 16. The cathode 6 is made with a discharge cavity 7 in the form of a rectangular through slot. The insulating tube is made with three processes. Mathematical dependences are given between the lengths of the sides of the cathode slit, as well as between the diameters of the processes of the electrically insulating tube and the dimensions of the cathode slit. 3 il.

Description

The invention relates to a class of gas-discharge light sources, in particular to spectral high-intensity lamps emitting narrow resonance lines of various chemical elements.

The purpose of the invention is to increase the intensity of radiation of resonant lines.

Fig. 1 shows a spectral high-intensity gas discharge lamp with a combined discharge for atomic absorption and fluorescence, a general view; in figure 2, 3 - slit cathode, rotated 90 °, section.

The lamp is a cylindrical glass cylinder 1 with a flat window 2 for the radiation to exit. The flask is equipped with a process 3, where a thermal cathode 5 is mounted on two molybdenum leads 4 in the form of a double tungsten helix coated with oxide. Glow cathode 6

has a cylindrical shape with a discharge cavity 7, having the form of a slit with dimensions h - the depth of the slit. 2 - length, s - width. The ratio of these linear dimensions of the discharge cavity satisfies the expression

li: l2: l3 (4.0-3.5) :( 3.0-2.5) - (1.5-1.5) (1.5-4.0).

The glow discharge cathode 6 is provided with a process 8, inside which a hole 9 is drilled to accommodate a molybdenum outlet 10, installed with a small gap inside the electrically insulating tube 11 having processes 12 and 13 with diameter di and process 14 with diameter d2. The cathode 6 is made of some refractory material, for example, a 29 nk alloy (covar) of vacuum melting, and the inner surface is made of a metal whose spectrum is to be obtained. Chip 1-1 turns into

Oh h

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a glass tube 15 in which the pin anode 16 is placed. The second end of the anode 16, the molybdenum lead from the hollow cathode, and the electrically insulating tubes 11 and 15 are mounted on a glass leg 17. The inner surface 18 of the discharge cavity of the cathode 7 is made of a material whose spectrum is necessary to obtain. The lamp is filled with inert gas to the required pressure through the appendage 19. When such a lamp is connected to the power supply, the glowing discharge is triggered between the side surface 18 of the discharge cavity of the cathode 7 and the anode 16. Under the influence of intense ion bombardment, the cathode material is sprayed. Sputtered products in the form of neutral atoms fall into the region of the cathode glow and are additionally excited in the positive column of the arc discharge, burning between the thermal cathode 5 and the anode 16. The radiation leaves the cavity of the cathode through flat windows 2.

These differences make it possible to increase the radiation intensity of the resonance lines by using a hollow cathode with a slit discharge cavity, efficient use of an arc discharge passing directly through the discharge cavity of the cathode, and the use of an electrically insulating tube, the design of which allows both discharges to pass through short directly through the slit discharge cavity, and the radiation output in the direction perpendicular to the discharge axis.

An example of a specific implementation. The lamp is a cylindrical glass cylinder with a flat window for exit of radiation, made of UT 49 material. The cylinder has a glass process of 040 mm and a length of 50 mm, inside of which a spiral thermocathode coated with a molybdenum pin is attached.

triple calcium carbonate, strontium and barium. A glow discharge cathode is installed inside a glass tube with a gap of 0.5 mm and has three processes. The processes facing the thermocat and anode have diameters of 12.0 in the direction of a flat window of 010 mm. The length of each process is 8.0 mm. The anodic process passes directly into the tube, inside which there is a molybdenum rod with a diameter of 1.5 mm, which is simultaneously both the output and the anode. The lamp is filled with neon inert gas to a pressure of 8 mm Hg.

Claims (1)

Invention Formula Spectral high-intensity lamp for atomic absorption and fluorescence, containing a flask with a flat window for the output of radiation, inside which a thermal cathode, an anode and a cathode are installed A discharge with a cavity having a rectangular shape in cross section, the walls of which are made of a material that determines the emission spectrum, characterized in that, in order to increase the intensity of the radiation of the resonance lines, it is equipped with an electrically insulating tube made with three spikes, two. of which have the same diameter di and are located on the discharge axis, the perpendicular direction of the radiation output, and the third is coaxial with the window, the anode and cathode of the glow discharge are located inside the specified tube, and the cathode cavity is made through and has a slit shape in the direction discharge axis with the following ratio of tube sizes and sizes h: l2: l3 (4.0-3.5) :( 3.0-2.5) :( 1.5-0.5) n and where p (1.5-4.0); And, 2 and s - the depth, length and width of the slit, a ds - the diameter of the third process of the tube. 7 ft Fig1 eri a 2