Abstract: A system for time resolved spectroscopy comprises a CCD device arranged to receive a time varying spectrum. Time resolved spectroscopy is the analysis of a spectrum that varies with time due to any cause. The variation with time of the spectrum may be due, for example, to (i) changes of the spectrum from a given sample space with time (such as due to emission decay); and (ii) changes in the spectrum as successive portions of a sample space are sampled (such as laser scanning microscopy). The CCD device comprises an array of photosites arranged to detect the time varying spectrum and to produce signal charge representative of the spectrum, and one or more CCD multiplication registers arranged to receive the signal charge and to provide charge multiplication. An enhancement of speed and sensitivity is given by a storage area which receives the signal charge in parallel from the array of photosites to provide the charge in serial to the one or more multiplication registers.

Abstract: A magnetron including a cathode, an anode axially aligned with the cathode and including a plurality of radial vanes defining resonant cavities, an output coupler connected to a first set of the vanes, a second set of vanes not connected to the output coupler, and extensions formed on only the vanes of the second set, the extensions extending in the axial direction towards the output coupler in a direction parallel to the axis of the anode, the extensions not being connected to the output coupler, whereby a capacitance between the axial extensions and the cathode at least partly compensates for the capacitance between the output coupler and the cathode.

Abstract: A magnetron includes a cathode and a vacuum envelope in which the cathode extends. The vacuum envelope includes a portion extending radially relative to the axis of the cathode. A pair of electrically conducting support arms for supporting the cathode are in electrical connection with cathode supply terminals. The support arms have free ends connected to the cathode by leads. A wall extends across an area of the radially-extending portion. The wall is positioned along the radially-extending portion nearer to an end of the radially-extending portion that is adjacent to the cathode than to an end that is remote from the cathode and the support arms are mounted in the wall.

Abstract: A magnetron includes an anode with an anode casing at least partly surrounding the anode. A pair of permanent magnets on each side of the anode define an interaction region and create a magnetic circuit defining a magnetic field through the interaction region. A mass of magnetically permeable material is positioned in a vicinity of the magnetic circuit. The mass is arranged to be slidable over the anode casing. A locking device secures the position of the mass to set the strength of the magnetic field through the interaction region.

Abstract: A magnetron has a cathode, an anode with vanes, and an insulating surface which faces the cathode and receives material from the cathode due to sputtering at the cathode. A conductor enables the resistance of the film so deposited to be measured, giving an indication of the thickness of the film and the lifetime of the magnetron.

Abstract: A CCD Device of the type for providing charge gain by impact ionisation has a multiplication register. Gain provided by a subset of the elements of the multiplication register are independently controllable from other elements in the register. This enables the register to be used in one setting with the same gain applied to all elements and a different setting with a subset of elements arranged to provide a different gain. By comparing the two signals, the gain provided by each element and the register as a whole may be derived.

Abstract: An imaging apparatus for x-rays includes a scintillator, overlying an array of imaging pixels on a substrate, and at least one trigger pixel array externally peripheral to the array of imaging pixels on the substrate such that the trigger pixel array is not substantially overshadowed by the scintillator from incident x-ray radiation. A layer substantially impervious to light but transparent to x-rays overlays the trigger pixel array, such that the trigger pixels are unresponsive to light but triggered by direct hits from incident x-ray photons.

Abstract: A transformer comprises a secondary winding including a plurality of coaxially arranged toroidal closed magnetic circuits connected in series within an enclosure and a primary winding comprising a plurality of turns including electrically conducting members passing axially through the toroidal closed magnetic circuits, respective ones of the plurality of electrically conducting members being electrically connected by respective electrically conducting strip lines passing along walls of the enclosure to form the continuous primary winding.

Abstract: An enclosure (4) for electrical apparatus (6) has a sealable outlet (8) for partially evacuating the enclosure and a sealable inlet (9)for partially filling the enclosure with a liquid (7) having a vapor pressure at operating temperatures of the apparatus suitable to enhance electrical isolation of the electrical apparatus and suitable to provide convective cooling of the electrical apparatus. The vapor preferably provides a voltage hold-off sufficiently high for operating voltages of the electrical apparatus and has a relative permittivity sufficiently low to prevent stray capacitance in the electrical apparatus above a predetermined limit.

Abstract: An apparatus and method for comminution of ore material includes a radio frequency multi-input, multimode processing resonant cavity arranged for radio frequency electromagnetic irradiation of a stream of ore material passing therethrough. A multi-input measurement resonant cavity, located upstream of the processing resonant cavity may be provided to determine an impedance of ore material to be irradiated in the processing resonant cavity. The radio frequency electrical field generated in the processing resonant cavity is matched to the determined impedance.

Abstract: An apparatus for applying electromagnetic energy to a dielectric fluid includes a chamber (20) to contain the dielectric fluid. A at least three parallel or coaxial electrode plates (401-409) is arranged within the chamber to apply substantially equal electromagnetic energy per unit volume of the dielectric fluid between neighbouring ones of the at least three electrode plates. Electrical conductors (416, 426) are electrically connected to electrode plates to apply a radio frequency electric field between neighbouring ones of the at least three electrode plates. In a first embodiment the electrode share connected in series and in an alternative embodiment the electrodes are connected in parallel.

Abstract: A CCD device of the type which provides gain by impact ionisation in a multiplication register includes an arrangement for production of a first output signal derived from a known input with multiplication applied and a second output signal derived from a different input with unit gain applied. Using the known ratios of the two signals, the gain of the multiplication register can be determined. The two signals can be derived from accumulating thermal charge in elements a CCD image device and by summing charge to produce a signal processed with unity gain and by averaging charge for use with the signal with gain applied. An alternative embodiment uses an extra light source for producing input signals of known ratio.

Abstract: Vertical and horizontal smear in images produced by a CCD imager can be compensated for by detecting the boundaries of the smear and substituting data from an alternative part of the image, or interpolated data within those boundaries. Vertical, or frame transfer, smear can also be compensated for by producing an error signal from charge accumulated during frame transfer and corresponding to one or more masked rows of the CCD imager. This error signal can be subtracted from the line signals corresponding to each row of the CCD images receiving radiation during image acquisitions. The CCD imager includes a multiplication register. The dynamic range of the imager may be extended by varying the gain of the multiplication register, for example on a line-by-line or frame-by-frame basis.

Abstract: A CCD sensor has a shutter to prevent frame shift smear during transfer of an image from the image region to a store region. The CCD sensor has an extended dynamic range, because each integration is in two parts, the second part of which has a different sensitivity than the first part. In order to avoid an asymmetry in the uncovering and covering of the image region, a two-bladed shutter is used.

Abstract: A CCD such as a frame transfer CCD has an extended dynamic range. The image built up in the image region 1 in each integration period is transferred to the store region 2 in each frame transfer period, for example, at a TV signal rate. The dynamic range is increased by dividing the integration period into two parts, and clipping the signal in the first part, but not in the second. The signal is clipped by pulsing the clock electrodes of the image region so as to combine the charges from adjacent wells together, overspill being drained into the anti-blooming structure, consequently reducing well capacity.

Abstract: An RF generator power supply comprises a first switched mode power supply (SMPS) connected in series to a second SMPS by a DC bus. A capacitor is arranged between the outputs of the first SMPS and inputs of the second SMPS to act as a smoothing capacitor for the first SMPS and to supply pulse energy to the second SMPS. The second SMPS has an output connected to an input of a step-up transformer and an output of the step-up transformer is connected to an input of a rectifier connectable to the RF generator. An input of the first SMPS is connectable to a prime power supply to maintain a high power factor with low harmonic content while setting an operating voltage and peak current level for the RF generator. The second SMPS is arranged to feed the step-up transformer and is arranged to operate with a variable duty cycle and/or variable frequency to provide average power control of the RF generator. The second SMPS is rapidly switched off on detection of a power surge through the RF generator.

Abstract: A radiation sensor 10 includes an array of imaging pixels 13 electrically connectable to a readout port. At least one first peripheral row of trigger pixels 11 is located at a first edge of the array, the trigger pixels also being electrically connectable to the readout port but responding faster to x-rays than the imaging pixels. At least one second peripheral row of trigger pixels 12 may be located at a second edge of the array opposed to the first edge. Trigger pixels 11, 12 from the first and second peripheral rows may be addressable alternately in a predetermined pattern to detect a radiation signal for triggering the sensor. Various methods of clocking the sensor are also described. The sensor has particular applicability to intra-oral x-ray imaging.

Abstract: An output window for a vacuum electron device comprises an output waveguide, an intermediate layer of dielectric material joined to the interior of the output waveguide with a vacuum-tight seal, and upper and lower layers of dielectric material spaced apart from the intermediate layer and arranged above and below, respectively, the intermediate layer in a vertical orientation of the output waveguide. The upper and lower layers including openings. Supports extend inwardly into the output waveguide and support the upper and lower layers. Pillars extend through the openings in the lower layer and support the intermediate layer. The openings in the upper and lower layers permit a venting of a region between the upper layer and the intermediate layer and a region between the lower layer and the intermediate layer during the sealing of the intermediate layer while the intermediate layer is supported by the pillars.

Abstract: A photoelectric sensor array is labelled by accumulating charge, preferably charge from a dark current, in at least a portion of the sensor array and reading out the accumulated charge to form an image to determine locations of atypical pixels in the portion of the sensor array. A signature of the sensor array is generated from the locations of atypical pixels and stored. The array is subsequently identified by re-accumulating charge in the portion of the array to form a signature based on the atypical pixels for comparison with the stored signature.

Abstract: An electrical apparatus having a cooling system includes a first cover to cover a first part of the electrical apparatus to be cooled and a second cover substantially enclosing the first cover to define a surrounding space. A base plate on which the first cover is mounted defines an environmentally-sealed enclosure that houses the first part of electrical apparatus. A first circulation device causes air to circulate in the environmentally-sealed enclosure and a second circulation device causes a cooling fluid to circulate around the surrounding space. A heat transfer structure is positioned on each side of the first cover. A third cover is mounted to an opposite side of the base plate from the first cover to define a second enclosure that houses a second part of the electrical apparatus to be cooled. A heat exchange structure is positioned within the second enclosure. The second circulation device is arranged to drive cooling fluid both through the heat exchange structure and through the surrounding space.