SU1211828A1 - Device for generating ultraviolet radiation - Google Patents

Abstract

The invention relates to gas discharge lamps and can be used, for example, in spectroscopy. The purpose of the invention is to increase the reliability of stabilizing the intensity of the output UV radiation. The cathode 2 material during ignition of the glow. In the gap, the cathode 2 - anode 4 is deposited on the surface of the window 6. When the radiation intensity decreases, the signal from the intensity comparison unit 10 through the source 12 ignites an additional low-current glow discharge between the electrodes 5 and 7. Positive plasma ions The glow cathode-2 anode 4 is accelerated and sputter is sprayed on window 6. Electrode 7, which is the anode, is connected to the anode 4 through a resistor 9 and is in the form of a grid. The projection of the grid of the electrode 7 onto the surface of the window 6 is within the limits of the projection of the grid of the electrode 5. The invention is additional to the author. St. No. 1 il. i (Л С

Description

one

The invention relates to gas discharge lamps emitting in a given spectral region, and can be used in spectroscopy, photochemistry, etc. The invention is an improvement of the known device described in ed. St. No. 1069033,

The purpose of the invention is to increase the reliability of stabilization of the intensity of the output UV radiation during operation by increasing the transparency of the output window.

The drawing shows a diagram of the device.

The device for creating UV radiation contains a flask 1, in which hermetically placed having external leads (not shown) are hollow cathode 2, screen 3, anode 4 and auxiliary electrode 5 in the form of a ring with a mesh of low material fixed on it the coefficient of dispersion (in the case of a quartz bulb 1, the electrode 5 V1z is made of molybdenum). Electrode 5 is installed near the exit window 6 of a material that is transparent to UV radiation, mainly quartz. Between the electrode) m 5 and the inner surface of the window 6, there is an additional anode 7, the design of which is similar to that of the electrode 5, connected via a dielectric conductor 8 insulated by dielectric tubes and a high-resistance resistor 9 to the anode A, which is the closest to the window 6 electrode node of the lamp. Such a connection allows to simplify the placement in the flask 1 of the insulated terminals 8 and the resistor 9. The lamp is also simplified because, by placing the resistor 9 inside the flask 1, the number of individual hermetic leads in the flask 1 is reduced. Especially important when making flask 1 of quartz glass. Flask 1 is filled with inert gas. On the way (along arrow A) radiation from flask 1 is through window 6, partially deflecting (along arrow B) radiation is set to control unit 10, plate 11, and the output of high voltage source 12, voltage is connected to the output of electrode 5 on the outlet is constant, and plus is connected to ground (grounded). The resistance of the resistor 9 is selected from such a calculation.

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It is necessary that the discharge current between electrodes 5 and 7 be of the same order as the ion current on window 6.

When powering up the main elements between the cathode 2 and the anode 4, a glow discharge is ignited, the radiation of which through the window 6 is directed to the object (along arrow B), and part of the radiation is deflected by the plate

10 ko 11 (according to arrow B) in block 10, where the radiation intensity is compared with a given limit level. During operation of the device, the electrode, mainly the cathode 2,

15 are dispersed in the glow discharge, a part of the products of this spray reaches the surface of the window 6 and accumulates on it, an image, visually hardly detectable, but retarding the UV radiation, therefore during operation the intensity of the UV radiation of the lamp decreases. The intensity of the radiation to a predetermined limit, block 10, turns on the source 12, and a high-voltage (5 kV) constant negative voltage appears on the electrode 5. Under the influence of this voltage between the electrodes 5 and 7, a low-Q glowing discharge occurs, moreover, the positive plasma ions of the glowing discharge between the cathode 2 and the anode 4, penetrating in the direction of the window 6, are accelerated in the direction of the electrode 5, acquiring at the same time, the energy sufficient for spraying on the window 6. As the electrodes 5 and 7 are made in the form of a relatively rare mesh of thin molybdenum wire, the main part of the positive ions reaches the surface of window 6, but unlike the known device, when approaching the window 6 is not reduced energy ions have been formed upon the low-current glow discharge between the electrodes is 5 m 7 electrons under the influence of the repulsive negative field electrode 5 move toward the window 6 and neutralize the positive charge on its surface. This process is stable throughout the lamp's lifetime, since ke depends on changes in the surface properties of electrodes 5 and 7, as well as window 6 (such as secondary electron emission, surface resistance, etc.), so unlike

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The window cleaning device 6 is carried out with high efficiency in all lamp samples during their entire service life. The glow of a low-current glow discharge between electrodes 5 and 7 is very weak and does not noticeably affect the radiation of the device. Electrode 5, operating in this discharge as a cathode, is made of sparse material according to the basic invention, therefore its spraying in a low-current discharge is very small and does not affect the operation of the device. The coincidence of the projections of the grids of the electrodes 5 and 7 on the window 6 eliminates the additional radiation shielding, and also minimizes the accelerated positive ions captured by the electrode 7. This positive effect is achieved even if the density of the cells of the grid of the electrode 7 is less than that of the grid of the electrode 5, by a factor of 2-3. Under these conditions, after switching on the source 12, an effective cleaning of the surface of the window 6 occurs, and the UV intensity of the device increases, the unit 10 detects this and turns off the source 12, after which the discharge between the electrodes 5 and 7 goes out and the lamp goes into normal operation. Thus, during the operation of the device, the intensity of the UV radiation generated by it fluctuates only within the specified limits.

The proposed device for creating UV radiation ensures the reproduction of the intensity level from Composer B Alexandrov Editor L. Avramenko Tehred O. Vashchishi a Corrector E. Roshko

Order 648/58 Circulation 644 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Rauschsk. nab. d. 4/5

Branch PPP Patent, Uzhgorod, st. Project, 4

radiation with less time finding a high-voltage power source in the on state than in the case of the known device, since the window cleaning efficiency of UV-retarding films appearing on it increases as compared with the known device, and the indicated efficiency is maintained at an increased stable level throughout the entire operation time of devices a, regardless of the change in material properties of the launch window and other parts. All this increases the reliability of the device while ensuring a high level of stability of the UV radiation, respectively, increasing the technical and operational characteristics of the equipment in which the device is used.

Claims (1)

Invention Formula A device for producing ultraviolet radiation. St. No. 1069033, characterized in that, in order to increase the reliability of stabilizing the intensity of the output ultraviolet radiation during operation, it is provided with an additional grid-shaped anode, located between the auxiliary electrode and the output window and electrically connected via a resistor to the main anode. the grid of the additional anode on the inner surface of the window is within the projection of the grid of the auxiliary electrode on the same surface.