Abstract:
The electron multiplier array consists of a plurality of multiplier channels (1) with each channel generally comprising a substrate (2), an anode (5) and a series of stacked insulation layers (7) and dynode layers (11) describing the walls of the channel. The electron multiplier array is robust and reduces the extent of the correction required for variations in performance between channels.
Abstract:
An optical micro sensor (1) for measuring one or more environmental parameters, such as pressure and temperature, through the modification of incident radiation. The sensor (1) is fabricated using MEMS technology and is adapted to receive an optical fibre (40) which communicates radiation to and from the micro sensor (1). The sensor (1) has an environmentally-sensitive element (4) which modifies the incident radiation communicated by the optical fibre (40). The modified radiation is communicated back along the optical fibre (40) and provides information regarding the environmental conditions surrounding the sensor (1). The pressure sensor is provided with a Fabry Perot cavity (3) in a first surface of a silicon wafer (2). The cavity is covered by a reflector at the environmentally-sensitive element (4). The diameter of the channel (7) holding the optical fibre (40) is greater than the diameter of the cavity (3). The temperature sensor is provided with luminescent material at the element (4). Also, a method of securing an optical fibre to a silicon block is claimed.
Abstract:
An optical micro sensor (1) for measuring one or more environmental parameters, such as pressure and temperature, through the modification of incident radiation. The sensor (1) is fabricated using MEMS technology and is adapted to receive an optical fibre (40) which communicates radiation to and from the micro sensor (1). The sensor (1) has an environmentally-sensitive element (4) which modifies the incident radiation communicated by the optical fibre (40). The modified radiation is communicated back along the optical fibre (40) and provides information regarding the environmental conditions surrounding the sensor 1.
Abstract:
An imaging device comprising an array of pixels fabricated using a microelectronic technology such as CMOS is disclosed. The imaging device provides information regarding rapid increases in incident radiation. The sensor is sensitive to a variable quantity to be imaged, such as visible or non-visible radiation, and a signal representative of the quantity is output. The quantity is measured over a monitoring period, and the timing of the incidence may also be output.
Abstract:
A scanning tunneling microscope tip is used to direct a rapidly switched stream of electrons at a target surface by applying an electrical bias which brings the tip close to the auto-emission threshold, and then using a pulsed laser source directed at the tip to trigger emission. Applications include high time and space resolution spectroscopy, and data recording apparatus.
Abstract:
A permanent magnet assembly for use in for example magnetic resonance imaging apparatus comprises two spaced apart permanent magnets (1,2) which extend between two plates (3,4) of high permeability material. The permanent magnets and plates define a frame extending around an air gap (5) within which a honmogenous magnetic flux is to be generated. The permanent magnets (1,2) define end surfaces which bear against mating surfaces of the plates and poles of the permanent magnets of the same polarity face the same plate. The end surfaces of the permanent magnets are non-planar and shaped such that the lengths of inner side surfaces (10,11) of the permanent magnets that form sides of the air gap (5) are less than the length of outer side surfaces (12,13).
Abstract:
A method of identifying radiation detected in a wall-less proportional gas counter providing a stable pulse height spectrum. The method comprises i) transforming the detected pulse height spectrum (dn/dx) in accordance with the transform u=x where x represents the energy of the detected pulses in the original pulse height spectrum; ii) generating a normalised spectrum in u-space comprising a representation of dn/du as a function of u, where n is the detected pulse count as a function of x; iii) deconvoluting the normalised spectrum in u-space to enhance the spectrum; and iv) determining from the enhanced spectrum the energy (or energies) and/or the intensity (or intensities) of the detected radiation.
Abstract:
A cryostat includes a rotatable mounting arranged to rotate about a first rotational axis, the mounting extending substantially in a first plane, a sample plate arranged in use to support a sample, located on the rotatable mounting, and a heat sink located adjacent the side of the mounting distant from the sample plate. A thermal conductor extends between the sample plate and the heat sink. The conductor extends through an aperture in the rotatable mounting. A rotatable sample holder for a cryostat includes a sample plate having a first side arranged in use to support a sample, a drive gear arranged to rotate about a first rotational axis, and a driven gear arranged to rotate about a second rotational axis, engaged with the drive gear and coupled to the sample plate such that rotation of the drive gear causes the driven gear and sample holder to rotate. The first rotational axis does not intersect the second rotational axis.
Abstract:
A method of fabricating an electron multiplier array in which a plurality of apertures are etched through a construct (20) of a dynode layer (11) and an electrical-insulating layer (12) with a jet of hard powders (22). The construct (20) is then divided into smaller discrete segments and stacked such that the apertures in adjacent segments align to form channels. Alternatively, rather than dividing the construct (20) into smaller segments, a plurality of constructs (20) may instead be stacked to create a large-area electron multiplier array.
Abstract:
The terahertz camera has a fixed objective lens (2) and a plurality of detectors (3) positioned at the focal plane of the objective lens (2). Each of the detectors (3) is mounted on a movable support (10) so that the antenna is capable of movement across the focal plane of the objective lens (2) and is provided with a flexible waveguide (4) for connecting the output of the detector (3) with signal processing means. Each detector (3) is also provided with a retroreflector (6) which is reflective at frequencies other than terahertz frequencies. During use of the camera, the retroreflector (6) of each detector (3) is illuminated at non-terahertz frequencies so that the spatial position of each detector (3) and hence the spatial source of signals generated by the detector can be accurately identified. The terahertz camera is particularly suited for use in security installations and in chemical and food processing industries.