Radiation hard vacuum switch

#The present invention relates to a radiation hard vacuum switch and more specifically to a radiation hardened closing switch for a applied between an anode lead and a cathode lead.

#Circuit designers require a radiation-hard system to couple a trigger signal into an exclusion region without wires and with several kilovolts of isolation so that a capacitor discharge circuit can be switched. Known exclusion region circuits do not have or meet the radiation hardness requirements. These systems utilize a LED light shining through a long opening to impinge on a silicon photodetector with subsequent amplification of the detected light pulse providing the main switch trigger. Due to the presence of many semiconducting elements in such a light amplification configuration, the resulting system is not radiation hard or insensitive.

#Therefore, it is an object of the present invention to provide a vacuum switch system which will overcome the above-noted disadvantages.

#The present invention will become more fully understood from the following detailed description given herein below and the accompanying figures which are given by way of illustration only and thus are not intended to be limitative of the present invention, and wherein:

#FIG. 1 represents a schematic diagram of the plasmatron circuit scheme of the present invention;

#FIG. 2 represents a sectional view of the plasmatron or vacuum switch of the present invention; and

#Referring now to FIG. 1 there is seen a schematic of the plasmatron circuit scheme of the present invention. The plasmatron or trigger circuit is inclusive of a trigger pulse 1, an opening or aperture 2, herein represented dimensionally as a 30 mil diameter.times.60 mil long opening, and the vacuum switch 3 which is triggered via plasma expansion created by the trigger pulse 1 which travels through the aperture 2 to reach the isolated vacuum switch 3. The plasma arc generated is directed by the aperture to the space between the vacuum switch anode and cathode, completing the electrical connection therebetween so as to, in turn, provide the switching action to trigger a main switch 4.

#FIG. 2 illustrates a sectional view of the plasmatron of the present invention. The radiation-hard vacuum switch 10, for the purposes of the present invention, is inclusive of a trigger probe 11, a connecting orifice or aperture 12, and a vacuum switch 13 including an anode 14 and a cathode 15 existing in a vacuum. Ceramic ring 24 electrically isolates anode 14 from shell 16. Ceramic ring 25 isolates the structure supporting cathode 15 from anode 14. The return of the trigger probe 11 is grounded to the shell 16 of the switch 10 through a layer of carbon 17 coating the end of the ceramic cylinder 18 through which the trigger probe 11 extends. When the switch is to close, a trigger pulse is applied to the trigger probe 11, causing a plasma arc to be generated which is directed by the aperture 12 in the shell 16 to the space which exists between anode 14 and cathode 15, causing conduction therebetween. Once the anode voltage arcs to the cathode it sustains conduction. A switch anode lead 19 and switch cathode lead 20 completes the plasmatron structure.

#A vacuum is pulled through a copper tube 21 which is pinched off to hold the vacuum. Slots, not shown, are provided in the sides of the copper tube above the aluminum cathode and vent holes 23 in the shell to ensure that all gas is evacuated. The outer surface of the shell 16 is preferably gold plated to prevent the permeation of gases, typically hydrogen, through the shell. The anode 14 is corrugated to increase its surface area.