Abstract: A method and apparatus are provided for measuring effective focus of an electron beam directed at a target. The electron beam imparts heat flux into the target to effect a target surface temperature profile thereon. A mathematical process model is used to predict an initial iteration of the temperature profile based on operating beam parameters and based on heat transfer behavioral relationships of the target. The temperature profile is optically measured and then compared with the initial iteration to obtain a residual error therebetween. The predicted temperature profile is iterated by varying the beam focus operating parameter until the residual error is less than a predetermined value for determining the effective beam focus.

Abstract: A compact power circuit configured for circuit breaker applications includes, in one embodiment, a plurality of current transformers, each current transformer being coupled to a respective one of the phase lines of a power line to generate a current proportional to the current in the respective one of the phase lines. The circuit also includes a plurality of operational amplifiers, each of the operational amplifiers being coupled to a respective one of the current transformers. The operational amplifiers generate the phase signals v.sub.a, v.sub.b and v.sub.c respectively. A neutral phase signal Vn is generated by a current transformer coupled to the neutral phase line of the power line. A ground fault signal is generated from the vector sum of signals v.sub.a, v.sub.b, v.sub.c and V.sub.n.

Abstract: A welding fixture includes a stationary tubular outer manifold having an outer flow passage extending radially therethrough for drawing vacuum, and a tubular spindle extending coaxially therethrough. The spindle includes a mandrel at one end over which the bore of a tubular body is positioned. A sleeve at the opposite end of the spindle is used for rotating the spindle. An inner manifold adjoins the sleeve and is disposed inside the outer manifold, and has an inner flow passage extending radially therethrough and disposed in flow communication with the outer passage for drawing vacuum inside the spindle and in turn inside the body for retaining a disk thereon. An annular flange adjoins the mandrel and the inner manifold, and has a seat facing the mandrel for receiving the body at a complementary counterbore, and also includes a bearing land disposed in contact with the outer manifold for rotation thereon.

Abstract: A method is disclosed for operating an electron beam physical vapor deposition apparatus including a vacuum chamber containing an ingot disposed in a crucible, a workpiece disposed above the ingot, and an electron gun for emitting an electron beam to melt and vaporize the ingot to disperse vapors for deposition coating of the workpiece. The method includes directing a primary electron beam with a primary beam focus in a primary scanning pattern across a top surface of the ingot to melt and vaporize the ingot and develop an ingot melt pool floating atop an underlying ingot substrate. A secondary electron beam is superimposed across the ingot top surface in conjunction with the primary electron beam. The secondary electron beam has a secondary beam focus in a secondary scanning pattern to locally and transiently increase vaporization rate of the melt pool.

Abstract: An optical modulator includes pump and signal lasers optically aligned with an optical modulator element having a nonlinear refractive index. In operation, a pulsed optical pump beam is focused inside the modulator element for obtaining oscillatory sagittal and tangential mode radii thereof. A signal beam is propagated through the focus in the modulator element at a crossing angle with the spatially modulated pump beam for phase modulation thereof. Material nonlinearity due to electronic polarization or molecular orientation provides ultrafast rise times with correspondingly high modulation bandwidth.