摘要:
The present invention is directed to multiple aperture devices (MADs) for beam shaping in x-ray imaging. Two or more of these binary filters can be placed in an x-ray beam in series to permit a large number of x-ray fluence profiles. However, the relationship between particular MAD designs and the achievable fluence patterns is complex. The present invention includes mathematical and physical models that are used within an optimization framework to find optimal MAD designs. Specifically, given a set of target fluence patterns, the present invention finds, for example, a dual MAD design that is a “best fit” in generating the desired fluence patterns. This process provides a solution for both the design of MAD filters as well as the control actuation that is required (relative motion between MADs) that needs to be specified as part of the operation of a MAD-based fluence field modulation system.
摘要:
A method of manufacturing a semiconductor device, in which in a semiconductor body comprising a boundary between a higher doped region and a lower doped region radiation enhanced diffusion of impurity is effected across the boundary from the higher doped region into the lower doped region to form in the lower doped region a further region the lateral extent of which is substantially constant, said radiation enhanced diffusion being effected by directing a beam of energetic particles towards the boundary from the side thereof at which the lower doped region is present and to produce damage of the crystal structure in the lower doped region at least in the vicinity of the boundary, the orientation of the semiconductor body with respect to the incident beam and the energy of the particles being selected so as to produce channelling of the semiconductor body crystal lattice by the particles with a channelling range in the lower doped region which extends at least to the boundary. The method may be carried out with proton bombardment and particularly some novel junction field effect transistor structures are formed having channel portions of precisely controlled dimensions. The method may be used in the manufacture of a buried channel junction FET having a uniform pinch-off voltage for all parts of the channel. Also the method may be used to yield junction FET structures in which the output characteristics can be predetermined according to the cross-sectional shape of the channel region portions determined by the bombardment induced radiation enhanced diffusion with controlled channelling.
摘要:
The invention relates to a limiter for limiting the output signal from an amplifier, for example, a video amplifier, which limiter is provided with an amplitude-limiting two-terminal network and an auxiliary amplifier, a first terminal of the twoterminal network being connected to the signal output lead of the amplifier and a second terminal being connected to an auxiliary signal output lead of the auxiliary amplifier, a signal being derived from said auxiliary amplifier which is in phase opposition with the output signal from the amplifier. The output terminals of the limiter are connected to said first terminal of the two-terminal network and to a terminal of fixed reference potential respectively.
摘要:
A receiver for a synchronous pulse signal formed with the clock, carrier, and shift frequencies having mutual ratios of integers. The receiver has two channels controlled by a clock pulse generator synchronized to a received signal and followed by a pulse regenerator. The receiver is well suited for an embodiment using integrated circuits.