Abstract: A sealed, passively pumped, polycrystalline ceramic vacuum chamber and method for fabricating the chamber are disclosed. The body of the vacuum chamber is made from a polycrystalline ceramic, for example, alumina. The vacuum chamber includes one or more windows made from a transparent ceramic, for example, sapphire, to accommodate optical access, while remaining amorphous-glass free to minimize or eliminate helium permeation. The vacuum chamber components are joined via laser welding or furnace brazing and the completed chamber is bakeable at temperatures up to 400° C. The vacuum chamber can operate at high or ultra-high vacuum pressures for an extended period through the use of one or more getter-based pumps. The vacuum chamber may include one or more atomic sources depending upon the application.

Abstract: A device for rendering safe a detonator firing circuit by short circuiting multiple conductors in the circuit includes a base portion and cable piercing members. The base portion has a cylindrical block and apertures for retentively receiving the cable piercing members. The cable piercing member has a first end to impinge on and penetrate a cable insulation when forcibly attached to an external surface of the cable. The cable piercing member has a low electrical resistance and impedance to generate a short circuit between conductors of the cable. Also, a method for rendering safe a detonator firing circuit of by short circuiting multiple conductor cables or a pigtail connector of a detonator system.