SU983824A1 - Combined magnetic discharge getter ion pump - Google Patents

Description

(54) COMBINED MAGNETIC DISCHARGE GETTERNO-IONNAYA NAAS

one

The invention relates to vacuum technology and can be used for pumping electrovacuum and electrophysical devices, when spraying thin metal films by evaporation, in particle accelerators and other devices.

Known cook magnetically. discharge getter-ion pump, nuclear discharge magnetic discharge stage getter evaporator 13.

The pumping efficiency of such a pump is low due to the insufficient gas infiltration in the region between the getter evaporator and the magnetic discharge pumping stage.

Also known is a combined magneto-discharge getter-ion pump containing a sealed enclosure with pockets and magnetic discharge blocks in them, a getter evaporator and a gas ionizer in the region between the evaporator and E2 pockets}.

In this pump, the ionizer is made in the form of a grid, surrounding the evaporation element and supported by the cooling potential. However, the effect of such an ionisation is low efficiently, since the electrons produced by ionization quickly go to the cell anode, and positive gases cannot get to the body where they can be covered with an evaporator getter, since the body has the potential The baseline Avod cannot serve as a collective of positive ions. Therefore, the ions are collected only on the end cathode surfaces.

ts t x facing the central cavity and having a small area. Due to these PICTURES, the pumping efficiency is reduced.

The aim of the invention is to increase the pumping efficiency.

Claims (2)

The goal is achieved by the fact that in a combined magnetic torch with a getter-ion pump containing a sealed case with pockets placed in it and magnet discharges in them, a getter evaporator and a gas ionizer in the region between the evaporator and the pockets, the ionizer gas is made in the form ultrasonic radiation tel. 1 The drawing shows schematically the proposed combined magnetic-discharge retter-ion pump. The pump includes a housing 1 with an inlet 2 and pockets 3, in which magnetically discharged blocks are placed, which are made of anode 4 and cathode plates 5. A getter evaporator 6 is located in the central chamber of the pump. In case 1, an ultrasonic emitter 7 is mounted, oscillations of which penetrate the region bounded by the evaporator and the pockets of the magnetic discharge units. High electric potential of about 7 kV is applied to anode 4. The cathode bed 5 and pump housing 1 are grounded. Under the action of ultrasonic vibrations of the scientific research institute emitted by the radiator 7 into the region between the evaporator 6 and the pockets 3 with magnetic blocks, so-called cavitation cavities are formed, in which, as a result of the occurrence of large electrical voltages, the gas particles undergo ionization, activation and dissociation. The consequence of these processes is the appearance in the volume of a pump of ions and new electrons, excited gas particles and free radicals into which molecules consisting of homogeneous atoms, as well as complex molecules, are split. Ions and secondary electrons are affected by the electric field, which exists between the evaporator 6 and the anodes 4 due to the high potential difference between them. By acquiring energy in this field, ions are accelerated and reach negatively charged electrodes, including the pump casing, where they are covered with an evaporator getter, and electrons participate in further ionization by colliding them with gas atoms, and then . Excitation with ultrasonic vibrations, ions, and electrons causes chemical activity of the atoms of the evacuated gas. The chemical affinity between titanium atoms, for example, and an excited atom or gas molecule is higher. in the case of the interaction of titanium with unexcited gas particles. Enhanced chemical bonding occurs both in the getter vapors and on the sprayed film when the active gas particles are located near it. The components into which complex molecules such as CO, CO, HjO, CH4, and others break up due to dissociation are better pumped out. After cleavage, such molecules are either ionized and, in the form of ions, go to the corresponding collectors and get dusty with a getter, or are excited and chemically affected with it. The medium for the propagation of ultrasonic vibrations is a cloud consisting of sputtered parts of the getter and carbon, resulting from the thermal dissociation of carbon compounds with hydrogen and other gases near the accumulated evaporator, in combination with the atoms and molecules of the evacuated times and formed by the plasma. Experience shows that in the pressure range of 66-1О Pa, the frequencies of ultrasonic vibrations from 10 to 100 kHz are most effective. In this case, the frequency of the first half of the range corresponds to pressures - 10 Pa, and the second half - by pressure 6610 Pa. The oscillation intensity of the ultrasonic emitter in the range of (1-15) -1O W / m makes it possible to excite particle oscillations taking into account the composition of cf, frequency and the depth of propagation of ultrasonic oscillations. Compared with the known pump MHj in which the number of produced ions in the starting mode is low due to the fact that the discharge voltage drops to 500 V and the electron energy is insufficient for ionization, the generation of ions in cavitation cavities makes it possible to increase the pump start pressure to 66 Pa and halve the duration of the start-up period and the exit to the working pressure level. At the same time, the pumping rate increases, since it depends on the number of ionized and excited atoms and gas molecules, and the pumping selectivity decreases, since all gas molecules ionize regardless of the type of gas, which ions, hitting the collectors, reliably bleed by the getter in their places collect. Thus, the high pumping efficiency, which consists in increasing the starting pressure, reducing the pump start-up time, increasing its pumping speed at high pressures, achieves, due to an increase in the elementary processes in the central cavity of the pump, which is ensured by the ionizing action of ultrasonic radiation in the between the getter evaporator and the pockets of the magnet-discharge units. Claims of the Invention A combined magnetism-type getter-ion pump comprising a hermetic case with pockets and magnetically-mounted blocks inside them, a getter evaporator and a gas ionizer in the region between the evaporator and the pockets, characterized in that, in order to increase the efficiency of pumping, the gas ionizer made in the form of an ultrasonic radiator. Sources of information taken into account in the examination 1. Physics and technology of vacuum. Sat articles. Publishing house of Kazan University, 1974, p. 423. 2. USSR author's certificate number 387465, cl. H O1 J 41/00, 1973. ttf tt