Submission of cooling liquid is carried out through the tip 14 in branch pipe 11 and further in a cavity between the cathode and magnetic conductor. The cooling liquid (technically pure water) moves in the cavity, cooling the target, and there through the outlet fitting moves out.
Anode of MRS 7 in section has the form of a ring. The anode fastens by means of ring 16 and lead 17 to case of MRS 1.
For the chambers walls protection, isolating and mobile details from sprayed material in technological installation mounting of shields is provided. Shields are made of sheet stainless steel by thickness of 1 mm. At pollution screens remove and clean or replace new.
Current contact jaws to anodes are isolated wires. The description of the vacuum system and the accelerator with an anode layer design are brought in corresponding sections.
The magnetic system, being one of the basic constructive elements of magnetron system, should form by target surface a field of the established configuration and value with the minimal dispersion for the effective magnetic trap for electrons creation. Researches on prototyping of magnetic fields have allowed revealing the most expedient variants of magnetic system design from the point of view of simplicity and opportunities of magnetic field of demanded geometry and value receiving.
The magnetic system represented in figure 3.3, is enough simple and provides effective localization of plasma. In this design it is possible to use type-setting magnetic blocks, blocking them from above by the general polar tip.
Figure 3.3. The magnetic system of magnetron atomizer design:
1 - magnet; 2 - polar tip; 3 - flux of magnetic field; 4 - magnetic conductor.
For magnetron system it is necessary to provide value of an magnetic field induction B above the dispersion zone of 0,07 tesla. As the field is non-uniform, B makes 0,7 of magnet boundary value of induction: B=0.7·Bmax. Thus, Bmax=0.1/0.7=0.14 tesla [17]. For taking into account of magnetic field dispersion on crossing by power lines of target material we shall increase value of induction in 1,2 times. We shall finally receive demanded value of induction: B=0.17 tesla.
The magnet characteristic is residual induction Br – the maximal value of induction which the material after magnetization before saturation possesses. At partial demagnetization of magnet it is received demanded value of induction.
Thus, a condition of magnetic material choice is fulfilling the requirement:
B<Br. (3.23)
At designing magnetic systems it is recommended to use magnets of mass produce, whenever possible the elementary forms as bars, cylinders and cones as they are cheaper of figured, and the magnetic system collected from them usually possesses smaller dispersion [17]. Cast magnets make from alloys ЮНД4, ЮНДК15, ЮН14ДК24 and ЮН14ДК24Т2. However magnets from ЮН14ДК24 are most common. The value of residual induction of the given alloy makes 1,2 tesla, that meet the condition (3.21), the given alloy can be used in developed system.
Proceeding from MAS design, magnets are collected in the form of cast
bars: 330 items with the sizes 24,5
10,08,0 mm, weight of a magnet - 30g. The
magnetization direction is along the size of 24,5 mm [18].
The materials choice for details of magnetic conductor is defined by following requirements: big maximal magnetic conductivity and a big saturation induction. Proceeding from the named requirements, and also operating conditions of system we choose material of magnetic conductor - m-metal precision alloy 79НМ.
Let's make the stress calculation of MAS anode-collector. Calculation is conducted considering the anode as a casing. The casing is a body, at which one of three measurements is much less than two others.
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