Abstract: An apparatus for housing a focal plane array includes a tubular metal stem for housing a cryostat inside of it, and a hollow conical metal housing having its narrow end brazed onto the end of the tubular metal stem. A ceramic electrical interconnection assembly is rigidly sealed onto the wide end of the housing, having embedded electrical connections for providing electrical connections between the interior and exterior of the assembly. A metal ring-shaped mounting structure is rigidly attached to the ceramic interconnection assembly. A ceramic coldplate is sealed over the other end of the rigid metal tube in the interior of the structure for holding the focal plane array. The rigidity of the structure provides a known positional relationship between the coldplate and the mounting ring, to facilitate positioning the focal plane array during dewar installation. A metal cap is sealed to the mounting ring to provide a reworkable, hermetic closure.

Abstract: A double stage Stirling cryogenic cooler with an IR Focal Plane array detector directly mounted on top of the cooler's expander second stage and with the radiation shield assembly mounted and cooled by the expander first stage to a temperature range of 200-100 K.

Abstract: A dewar (20) useful in rapidly cooling a sensor (28) supported thereon includes a bore tube assembly having a cylindrical dewar bore tube (22) with an end cap (24) at one end to close the bore tube (22). The bore tube assembly is cooled by directing a stream of coolant at the interior of the end cap (24). The sensor (28) is mounted directly to the exterior surface of the end cap (24). A cold shield (34) partially encloses the sensor (28). A cold shield support bracket (38) mounts the cold shield (34) to the cylindrical side walls of the dewar bore tube (22) at a mounting location (36) axially displaced from the end cap (24) and therefore less effectively cooled than the end cap (24), so that heat is extracted from the support bracket (38) and the cold shield (34) less rapidly than from the sensor (28). From an uncooled starting condition, the sensor (28) is cooled to its operating temperature, and the cold shield (34) is cooled to its operating temperature, in about the same time.

Abstract: An infrared detector assembly (12) of the type used in munitions and night vision systems having an improved focal plane platform (10) construction. In accordance with this invention, the thermally conductive focal plane platform (10) supports a detector array (26) and integrated readout chips (28). The focal plane platform (10) includes relatively thermally non-conductive inserts (38) disposed in cavities (36) positioned generally below each integrated read out chip (28). The inserts insulate the chips (28) during cryogenic cooling of detector array (26). Freeze-out of the chips (28) is thereby inhibited.

Abstract: An infrared detector comprises an envelope in which a detector element (3) is mounted on an end of a cold finger (1). A chemically-active getter (30) is present in the space between the cold finger (1) and the envelope window (7) and outer wall (2). In accordance with the present invention the getter comprises a porous layer (30) of chemically-active getter material deposited on an inside surface area of the outer wall (2) at a location separated from both the cold finger (1) and the window (7). The getter (30) can be activated (or re-activated) by heating through the portion of the outer wall (2) on which the getter material (30) is deposited, e.g. using a heater coil (50). Preferably the getter material (30) on the outer wall (2) extends around heat reflector, e.g. a reflective surface area of the cold finger (1). The cold finger (1) may be operated to cool the detector element (3) while heating the layer ( 30) to activate the getter.

Abstract: A device for preventing evaporation of liquefied gas in a liquefied gas reservoir used to cool an EDS detector of an electron microscope or the like is disclosed. A cold head of a cryogenic refrigerator is disposed so as to fit an opening of the top of the liquefied gas reservoir and moreover a temperature measuring instrument or a level gauge is disposed within the liquefied gas reservoir so that the cryogenic refrigerator is automatically operated depending on the temperature within the liquefied gas reservoir or on change in the liquid level of liquefied gas. In the manner vaporized gas is condensed and reliquefied, thus suppressing wasteful dissipation of vaporized gas.

Abstract: A detector unit which is capable of outputting electrical signals proportional in magnitude to the intensity of that energy in a beam thereof which lies in two different wavelength bands. A beam splitter directs energy in those bands from the entire compass of the beam to a data detector and a reference detector, and bandpass filters and optical traps in front of those detectors ensure that only energy in the selected bands and from the beam reach them. The detectors are mounted in precisely aligned relationship with each other and the beam splitter on, and are electrically isolated from, a monolithic, conductive, isothermal support which allows them to be maintained at the same, selected temperature by a system including data and reference detector heaters and a temperature responsive controller.

Abstract: A transducer for nondispersive infrared gas analysis has heaters for the data and reference detectors to maintain the detectors at a selected temperature. A heater is also provided to heat the casing of an airway adapter associated with the transducer to a temperature high enough to keep condensation from forming. The detector unit is surrounded and electrostatically shielded by a boxlike component with barndoor extensions which are closed to shield the installed detector unit at that end of the shield through which the detector unit is installed. The detector unit, electrostatic shield, and a circuit board which carries power supply and preamplifier circuits are installed in the transducer housing which has separate end closures sealed thereto with a through fastener and internal guides for locating the shielded detector unit in the housing.

Abstract: A circuit for coupling infrared detector elements maintained in the cryogenic environment with a processing circuit maintained at a substantially higher temperature is disclosed. The circuit comprises a detector output sampling/comparing circuit electrically connectable to an associated detector element. The sampling/comparing circuit is disposable in a cryogenic environment along with the associated detector element. The circuit is constructed to receive power from a power source that is electrically and thermally isolated from the sampling/comparing circuit. The output of the sampling/comparing circuit being communicatable to a processing circuit while remaining electrically and thermally isolated therefrom.

Abstract: A cooling type infrared rays detecting apparatus is disclosed which prevents a fluctuation of an infrared rays image arising from a variation of the cooling temperature. The infrared rays detecting apparatus includes a dummy element mounted adjacent an infrared rays detecting device on a device mounting portion of an inner tube. The dummy element has a similar structure to that of each of infrared rays detecting elements of the infrared rays detecting device and is formed from the same material as the latter. A temperature variation of the dummy element is detected from a variation in resistance of the dummy element, and an output of the infrared rays detecting device is compensated for in response to the thus detected temperature variation to prevent a possible fluctuation of an infrared rays image arising from a temperature variation. Consequently, an infrared rays image of a high quality can be obtained.

Abstract: An infrared detector assembly (10) of the type used in munition and night vision systems having an RF activated getter (50). Such detector assemblies (10) include a tubular coldfinger (22) surrounded by a vacuum and which supports infrared detector array (26) and related components. In accordance with this invention, RF getter (50) is located remote from detector array (26) and engages an inner wall surface (56) of a metallic dewar housing (14). The RF getter (50) is activated via RF inductive heating directly through the metal dewar housing (14) such that sensitive IR detector components and hermetic braze joints are kept below their critical temperature. As a result, the present invention provides longer vacuum life and greater operational reliability of infrared detector assembly (10).

Abstract: A radiation detector assembly (20) includes a radiation detector (2), a silicon readout device (3) coupled to the radiation detector, and a platform 13 for supporting from a first major surface (13a) the readout device and the radiation detector. A second major surface (13b) includes a boss (14) for coupling, via an active brazing operation, to a cryogenic cooler. The platform is monolithic structure comprised of aluminum nitride (AlN) and eliminates at least one adhesive joint found in the prior art. AlN is selected because of its inherent material properties including a higher thermal diffusivity, relative to typical ceramic materials, for providing a reduced cooldown time of the detector to cryogenic temperatures. AlN also has a 300K- 77K thermal contraction characteristic that closely matches that of the silicon readout device and a high modulus of elasticity, thereby reducing distortion of the readout device thus minimizing stresses on indium bump interconnects.

Abstract: A compact low-cost fire detector responds quickly by detecting an increase in the concentration of carbon dioxide gas in the ambient air. The detector also calculates the rate of build-up of carbon dioxide. The detector avoids the use of moving parts by employing a differential temperature black body source of infrared radiation in conjunction with a dual pass band filter. One of the pass bands is located at the 4.26 micron absorption band of carbon dioxide gas and the other pass band is located at 2.20 microns at which none of the atmospheric gases has an absorption band. The latter channel serves as a reference and renders the detector immune to false alarms caused by dust or smoke particles in the air or due to deterioration of certain components. The fire detector makes use of a sample chamber that consists of a serpentine passage in a block of material, the walls of the serpentine passsage being highly reflective so as to act as a light pipe.

Abstract: A low temperature infrared detector for use in a cryostat having a cold finger. A cold plane is mounted upon the cold finger in heat transfer relationship therewith. A read circuit board is mounted upon the cold plane and a detector circuit board is placed over the read circuit and is connected thereto both electrically and thermally. A screen is fitted over the detector circuit board. The screen has a shoulder formed in its bottom wall into which the detection board is press-fitted and a window that frames the detecting circuitry through which the circuitry can be viewed by an IR source. Preferably, the screen is produced using electroforming techniques.

Abstract: An infrared image sensor includes a plurality of Schottky type infrared detecting elements (8) arranged in array formed on one main surface of a semiconductor substrate (1a) or in a vicinity of the one main surface to allow incident infrared rays from the other main surface of the semiconductor substrate (1a). In this infrared image sensor (1), a high concentration impurity layer (12) is provided between one main surface and the other main surface of the semiconductor substrate (1a), which layer being provided with an infrared ray transparent aperture for the corresponding predetermined unit of the grouped infrared detecting elements (8).

Abstract: A totally integrated thermal imaging system has a dewar housing including imaging optics, a scanning mirror and a curved detector array. The imaging optics constitute a meniscus lens and a spherical focusing mirror. The scanning mirror scans the image, and the spherical mirror focuses the scanned image onto the detector array. The meniscus lens advantageously corrects aberrations. A detector support provides access for cryogenic cooling of the detector, and individual cold shielding of the detector elements is made possible by the telecentricity of the optics. Processing electronics, at least a portion of which may also be disposed on the detector support, process the detector signals to display an image. The integrated structure advantageously eliminates any need for separate scanner, imager, detector dewar and electronics modules.

Abstract: An infrared detector is capable of preventing faulty detection attributable to stray infrared rays. The infrared detector comprises an outer cylinder having an inner surface coated with a black film, an inner cylinder having an outer surface coated with a multilayer film capable of suppressing reflection, and an infrared sensing element mounted on the inner cylinder. The combined effect of the black film and the multilayer film prevents the incidence of stray infrared rays, namely, infrared rays scattered by multiple reflection, at the infrared sensing element. The infrared detector can be provided with a plurality of infrared sensing elements to detect infrared rays of frequencies in different frequency bands by providing band-pass filters each having an optical aperture in combination respectively with the infrared sensing elements.

Abstract: A filler apparatus for cryogenic dewars, such as are used in infrared detectors in infrared spectrometers, has an inlet port funnel which is connected to a liquid delivery tube which extends downwardly and into the liquid coolant containment vessel of the detector. A gas discharge tube extends co-axially with and spaced outwardly from the delivery tube and is connected to the fill port of the detector to direct gas resulting from evaporation of coolant within the detector up to a gas outlet funnel which is itself co-axial with and spaced outwardly from the inlet port funnel. A screen is mounted over the tops of the inlet and outlet funnels. The coolant, such as liquid nitrogen, is poured by the operator into the inlet funnel, which may be located at a position on the top surface of the cabinet of the spectrometer, and the operator can observe whether the detector is overfilled by noting whether the coolant liquid overflows into the gas discharge tube or up into the space between the inlet and outlet funnels.

Abstract: A radiometric standard detector responsive to infrared energy comprises an indium antimonide photovoltaic generator, a first mirror and a vacuum dewar including a cold finger and a window. The first mirror and photovoltaic generator are positioned in the dewar to form an optical energy trap. The generator is on the cold finger. A second mirror is external to the dewar. The window, both mirrors and the generator are positioned so a beam of the infrared energy is incident on the window and a portion of the infrared energy incident on the window is reflected from the window to the second mirror, then back to the window.

Abstract: By controlling the temperature of a glass reservoir tube attached to a closed vapor cell, the vapor pressure inside the cell can be accurately controlled. The apparatus for controlling the reservoir temperature includes an electric heater, a temperature sensor, heat straps to distribute and remove heat from the reservoir, and a clamp to hold the apparatus in close thermal contact with the exterior of the reservoir. An external control circuit energizes the reservoir heater as required. In the preferred embodiment the vapor cell functions as an optical filter when filled with a heated metallic vapor such as cesium. The reservoir tube functions as the cold spot of the cell and contains a small pool of the metal in liquid form.This invention was made with Government support under N66001-86-R-0050 awarded by the Department of the Navy. The Government has certain rights in this invention.

Abstract: A detector comprising a pyroelectric detector, a temperature control mechanism including a thermoelectric heating/cooling element for keeping the temperature of the pyroelectric detector constant, a temperature sensor, and a temperature controller responsive to the detection signal from the temperature sensor for controlling power supply to the thermoelectric heating/cooling element, and control unit provided within the temperature controller for pyroelectric detector. Synchronizing the operation of the pyroelectric detector and the thermoelectric heating/cooling element such that the power supply of the thermoelectric heating/cooling element is turned on and off only when data is not being collected by the pyroelectric detector.

Abstract: A two-stage Joule-Thomson cryostat (10) has a first-stage cryostat (12) with a helical-coil heat exchanger (14) and and isenthalpic gas expansion orifice (20) that discharges a mixture of cooled gas and cryogenic liquid into a liquid cryogen plenum (26). A second-stage cryostat (30) with a helical coil heat exchanger (32), wound to a larger diameter than the first-stage heat exchanger coil (14), is wound around and in thermal contact with the liquid cryogen plenum (26). This arrangement achieves a high degree of interstage heat transfer and cooling of the gas flowing in the second-stage heat exchanger coil (32) by the liquid cryogen in the first-stage liquid cryogen plenum (26). In operation, a gas flow management system (60), designed for rapid cooldown, initially passes a first gas of high specific refrigerating capacity through both stages (12 and 30).

Abstract: A method and apparatus for simultaneously cooling and scanning an infrared detector assembly, by mounting the infrared detector assembly on the cold surface of a cylinder-piston type cooling device in the image plane of an optical assembly, and driving the cylinder through reciprocations with respect to the piston to also reciprocate the infrared detector assembly perpendicular to the optical axis of the optical assembly. The disclosed cooling device is a Stirling cooler having a compressor section and an expander section, and the cold surface, which is reciprocated and on which the infrared detector assembly is mounted, is the cold tip on the outer face of the cylinder in the expander section.

Abstract: The invention relates to a cold shielding arrangement for use with either an individual staggered element linear IR array or a staggered arrangement of a plurality of such arrays. The cold shielding arrangement consists of a slitted plate spaced from the arrays, each slit being arranged to restrict the field of view of the pixels in both columns of one array in the scanning direction, and a pair of interdigitated pixel level cold shields set on the surface of each array to restrict the field of view of the pixels in the resolution direction.

Abstract: For use as a substitute for liquid nitrogen cooled energy dispersive x-ray detection in spectrometry, the present invention comprises a cooper cold-finger having a lithium-drifted silicon detector and FET at one end, and a five-stage Peltier cooling stack thermally connected to the fifth stage through copper braid at the other end, an aluminum heat shield surrounding the cold-finger and thermally connected to the fourth stage of the Peltier cooling stack with a copper braid, a plurality of nylon spiders that support the cold finger within the heat shield and isolate them thermally, a stainless steel cap, a plurality of nylon spiders that support the heat shield within the cap and thermally isolates them, a heat sink in thermal communication with the hot end of the cooling stack, a remote water cooling system piped to the heat sink and mechanically isolated from vibrating the silicon detector, an ion pump to create a high-quality vacuum around the silicon detector, a motor drive to adjust the reach of the sili

Abstract: In a spectrophotometer having an oscillating grating, an entrance slit and an exit slit and a light source to irradiate said grating through said entrance slit, the grating and the light source are mounted on a heat sink plate and a fan is provided to blow air over both sides of said heat sink plate. A temperature sensing transducer is mounted in the heat sink plate to sense the temperature of the heat sink plate and the output of the temperature sensor is amplified by an amplifier to energize the electric motor of the fan to control the speed of the fan in accordance with the temperature sensed by the temperature sensor to thereby maintain the temperature of the heat sink plate at a constant value upon the system reaching equilibrium. In this manner, the wavelength drift of the system is reduced to a very low value.

Abstract: The black hole which a cryogenically-cooled infrared (thermal) detector ctes in a scene being observed by another such detector is obscured by inserting a partial transmitter-reflector on the optical axis of the detector. A black-body radiator projects an ambient-temperature image the same size and shape as the black hole onto the transmitter-reflector such that the other detector sees a combined image with no apparent black hole.

Abstract: Check processing apparatus including an offset pair of image-lift sites and an associated "Heat-Dump", with this apparatus preferably built as an add-on, plug-in module to be used in a check-sorting system.

Abstract: An infrared rays detecting apparatus is disclosed wherein the area of a loop provided by an element line and a grounding line formed on an inner tube is minimized to reduce an induced electromotive force to minimize production of noises so that correct detection can be accomplished. A grounding line is interposed for each arbitrary number of element lines on a surface of the inner tube, and the element lines are individually connected to output electrodes of an infrared rays sensor of the multi-element type while the individual grounding lines are connected to a common grounding electrode of the infrared rays sensor.

Abstract: A mesa (31) is formed from polyimide (or a similar polymer material) to achieve a high thermal resistance. In an exemplary thermal imaging application, an array of thermal isolation mesa structures (30) are disposed on an integrated circuit substrate (20) for electrically connecting and bonding a corresponding focal plane array (5) of thermal sensors (10). Each mesa structure (30) includes a polyimide mesa (31) over which is formed a metal conductor (32) that extends from the top of the mesa down a mesa sidewall to an adjacent IC contact pad (22). When the focal plane array (5) is bonded to the corresponding array of thermal isolation mesa structure (30), a thermally isolated, but electrically conductive path is provided between the sensor signal electrode (16) of the thermal sensor (10) and the corresponding contact pad (22) of the integrated circuit substrate (20).

Abstract: A heat imaging camera (3) for sensing convective conditions in boundary layer flows occurring on wind tunnel models (2), particularly at cryogenic temperatures, scans the model from the outside, thereby detecting the temperature distribution on the model surface. Detectors (9) that are sensitive to the long-wave infrared spectrum range are part of the camera and convert the heat information into electrical signals. The temperature distribution is displayed pictorially and graphically with the help of an evaluation unit (50). The detectors (9) are grouped in a detector mosaic (10) in the camera (3).

Abstract: A gas sample collection device and method for cold trapping individual gas bands from a gas source that may include a chromatographic separation and for spectrographically analyzing the individual gas bands. The device includes a vacuum chamber containing a rotatably supported highly thermally conductive transmissive substrate having a highly thermally conductive support axle and at least one transmissive surface for holding a sample deposited thereon. A gas inlet is provided for depositing a mixture of sample and matrix material on the transmissive surface which is maintained at a sufficiently low temperature to cause solidification of the gas. A first set of optical elements directs an incident beam of electromagnetic analytical radiation from a source onto the solidified deposit, while a second set of optical elements directs the portion of incident beam transmitted through the deposit and substrate to a detector that is sensitive to the spectral wavelengths being investigated.

Abstract: An infrared ray detector assembly for detecting a plurality of components such as hydrocarbons, CO.sub.2 and CO gases includes a housing member having a hollow interior and a portion transmissible to infrared rays and a holder member mounted within the hollow interior and having a plurality of separate compartments. An infrared detector is mounted in each compartment, and an optical filter is mounted over each compartment, abutting adjacent filters to respectively limit the wavelength band to each infrared detector, each optical filter having a substrate of approximately the same material and thickness.

Abstract: The invention relates to a spectrophotometer having a light source capable of alternatively producing near infrared radiation and another radiation other than the near infrared radiation, a dispersing section for dispersing radiation from the light source to provide substantially monochromatic radiation so that a sample is irradiated with the substantially monochromatic radiation to thereby provide sample radiation, and a sensing section for sensing the sample radiation. The sample radiation is subjected to energy absorption of a specific wavelength by the sample. The sensing section includes a first sensing unit having a near infrared radiation sensor, a second sensing unit having a visible/ultraviolet radiation sensor and a temperature control unit for holding the near infrared radiation sensor at a substantially constant temperature lower than the room temperature.

Abstract: An instrument for determining the concentration of a particular gas that might be present in a sample has no moving parts and is extremely compact. The instrument uses as a source of radiation a device that has a radiating element whose temperature is alternated between T.sub.1 and T.sub.2 and whose spectrum approximates that of a blackbody. Radiation from this source is passed through a dual pass band filter that has two non-overlapping pass bands, one of which is centered at a wavelength at which the gas absorbs and the other of which is centered at a wavelength at which the sample does not absorb radiation. After passing through this filter, the radiation passes through the sample chamber and then is intercepted by a detector which produces an electrical signal determined by the radiation intercepted. The electrical signal is processed to provide an indication of the concentration of the gas.

Abstract: A miniature multi-temperature radiometric reference is placed in an intermediate image plane (20) of a thermal imaging optical system in order to correct, in a real-time manner, non-uniformities among detectors (30). The radiometric reference comprises at least two reference elements (10) mounted on a thermolelectric cooler (TEC) (1) which may have several stages (6). The reference elements (10) are mounted on the same platform (3) of the TEC (1). Each element (10) has a surface (11), having a substantially uniform temperature, within the depth of focus at the intermediate image plane (20). All of the radiometric reference surfaces (11) are maintained at different temperatures, which can be simultaneously above and below the ambient temperature. This enables determination of a normalized detector response, and subsequent correction of the response of each detector (30) as a function of temperature throughout the range characterized by the temperatures of the reference surfaces (11).

Abstract: A thermal imager employs an intermediate field stop (8) which is preferably placed at an intermediate image plane (P) in front of a cryogenically cooled detector (1) mounted on a substrate (2). Radiation gathered by a telescope is directed onto the detector through an aperture (9) in the field stop. The field stop limits the rays which are emitted by the detector and substrate and which are subsequently retro-reflected back to the detector (called narcissus rays).

Abstract: A method and apparatus for correcting for the ballistic deficit effect that occurs when determining the spectra of radioactive substances with an ionizing radiation detector. Two pulses derived from each output pulse of the detector, each having different peaking times but both containing effects of the ballistic deficit, are compared to produce an error signal related to the difference of the peak heights of these two pulses. A part (or all) of the error signal is added to one of the pulses to produce a corrected amplitude pulse. In order to effectively compare the two pulses, each is separately stretched at its peak height. The corrected amplitude pulse is reformed for better handling by multichannel analyzer analog-to-digital converters, with a plurality of these reformed corrected amplitude pulses then being analyzed by the multichannel analyzer to achieve a nuclear spectra for which the ballistic deficit has been corrected.

Abstract: Apparatus in a thermal radiation detection device including optics having a focal plane comprising a cold mounting surface, a detector array, a standoff and apparatus for protecting the detectors from intense thermal radiation. The detector array includes a plurality of radiation sensitive detectors mounted on a carrier in thermal contact with the cold mounting surface. The standoff defines a cold platform proximate to the detector array and mounted to the cold mounting surface. A substrate includes a film of vanadium trioxide on a first surface, wherein the substrate is mounted to the standoff at the first surface and wherein the substrate is structured and arranged to interpose the vanadium trioxide film between the detector array and a radiation source and is located proximate the focal plane.

Abstract: A focal plane array having an interconnect bump that has high thermal resistivity, and which may be used to interconnect the detector and readout of the array. The detector and readout each have separate heat sinks with separate temperature controls. The readout may thus be operated at a higher temperature than the detector. A high thermal resistance interconnect bump is employed to limit heat leakage from the readout to the detector to an acceptable level, and to enable a thermal gradient to be maintained simultaneously with a net savings in refrigerator power. The heat sink for the detector is made in such a way as to not obscure the active area of the detector, that is, it is annular in shape so as to surround the active area of the detector. The interconnect bump comprises a thermally insulating pedestal comprising a material such as polyimide, for example, with an over-the-edge metallization employed as an electrical contact.

Abstract: A device chamber (12) is evacuated by pumping via an evacuation tube (35) to produce a vacuum space in communication with a chemically-active getter (30) which is provided in the tube (35) to getter gases from the evacuated chamber (12). In accordance with the invention, the getter (30) in the form of one or more movable bodies of the getter material is activated by heating in the evacuation tube (35) at a safe location (36) distant from the chamber (12). It is then moved towards the chamber (12) and is retained in the sealed evacuation-tube outlet (31) of the device. A vacuum-permeable screen (12) in the evacuation-tube outlet (31) inhibits passage of the getter material (30) into the chamber (12) where it might, for example, otherwise damage or obscure an infrared detector element.

Abstract: A thermal radiation sensor is suggested which comprises two receiver surfaces exposed to the radiation, one receiver surface (1) having a high absorption capacity with respect to the thermal radiation, the other (2) having a low absorption capacity, the two receiver surfaces (1) and (2) consist of a NTC resistance material and are combined in a bridge circuit together with two temperature-independent cermet resistors (3) and (4). In order to prevent a dependency of the measurements of such a sensor on the ambient temperature, the NTC resistors (1) and (2) comprise underlying heating layers (6) and (7) which keep the two NTC resistors at a constant temperature. Insulating layers (8) and (9) are provided between the NTC resistors (1) and (2) and the heating layers (6) and (7). The heating layers (6) and (7) consist of a cermet thick film with platinum or of a platinum thick film and have the shape of a meander. The insulating layers (8) and ( 9) preferably consist of a crystallizing glass.

Abstract: A multi-element infrared detector for thermal imaging, wherein the detector includes a main substrate, an aperture plate and a plurality of detector elements formed on the main substrate and arranged thereon in an array. Each detector element having a photosensitive zone and output and common terminal electrodes formed at opposite ends thereof. The aperture plate having at least one aperture for restricting the field of view of the photosensitive zone. The detector includes an auxiliary electrode formed on the rear surface of the aperture plate in a position to contact the common terminal electrodes when the device is assembled. The infrared detector also includes a common metal line formed on the substrate in a position to interconnect a plurality of common terminal electrodes and the auxiliary electrode contacts the common metal line.

Abstract: An Atomic Photo-Absorption Force Microscope 1 includes an Atomic Force Microscope 10 and a radiation source 20 having an output radiation 22 wavelength selected to be preferentially absorbed by atoms or molecules associated with a sample surface 24a under investigation. Absorption of the radiation raises at least one outer shell electron to a higher energy level, resulting in an increase in radius of the atom or molecule. A tip 12 coupled through a lever 14 to the Atomic Force Microscope 10 is scanned over the surface and operates in conjunction with a laser heterodyne interferometer 18 to directly measure the resulting atomic or molecular increase of size, thereby detecting both the presence and location of the atoms or molecules under investingation. Operation in an a.c. mode by chopping the incident radiation 22 and measuring the corresponding a.c. induced tip movement beneficially increases the sensitivity of the technique, particularly if the a.c.

Abstract: A detector array assembly which provides for the closing at operating temperature of normally open contacts between individual sensor contact mesas and readout pads of the respective detector and readout chips comprising a detector array assembly. One or more shape memory separator elements are used in conjunction with one or more biasing springs to control the spacing of the contacts. The force of the biasing spring becomes the dominant force as the apparatus is cooled down to near operating temperature, thus moving the chips closer together and establishing reliable electrical connection between the opposed sets of contacts. At temperatures near and above the normal operating temperature of 77 degrees K., the shape memory separator element provides the dominant force and drives the chips apart to open the contacts.

Abstract: A cryostatic device is divulged for radiation detectors, disposed at the end of a cooled finger. A case, transparent to the radiation to be detected, at least in the vicinity of the detector, forms about the finger and the detector a heat insulating enclosure. An electric circuit brings the detected signal(s) outside the enclosure and radially immobilizes the end of the finger with respect to said case, because its substrate is a disk fast both with said case and with the end of the finger.

Abstract: A radiation shield 40 is mounted to an uncooled portion, such as an outer case 14, of an IR detector assembly 10 such that it surrounds a thermoelectric cooler 16 and a radiation detector 18. The shield 40 has a curved reflective upper surface 42 having the shape of a toric segment and cylindrical or rectangular reflective sidewalls 44 for imaging the detector 18 and the upper cooler stage upon the tops and sides of lower and slightly warmer cooler stages, which absorb and eliminate radiative energy. This beneficially reduces the heat load upon the coldest stage by excluding hotter surfaces from its view, and by inhibiting reflective couplings of unwanted energy admitted by aperture 46. An aperture 46 defines the effective coldstop for the detector 18.

Abstract: An IR sensing system wherein the focal area is located outside the casing at holds a detector array and a bundle of optical fibres leads from the focal area to the detector array in the array such that the inner, emitting end of each fibre of the bundle is in proximate relationship with only one single detector.

Abstract: A cryostat comprises a vacuum vessel, a partition wall for air-tightly separating the vacuum vessel into a first vacuum chamber and a second vacuum chamber, thermal shield tubes encapsulated within the first vacuum chamber, a cooler encapsulated within the thermal shield for containing therein a body to be cooled and cryogen for cooling the body to be cooled, a cryo-cooler disposed outside of the vacuum vessel, which has a cooling portion disposed within the second vacuum chamber, a heat transfer passage along which heat is transferred from the thermal shield tubes to the cooling portion of the cryo-cooler through a part of the partition wall, at least two openings provided in the second vacuum chamber, through which the second vacuum chamber is capable of being opened to atmosphere, and covers each detachably mounted to the respective openings for maintaining the second vacuum chamber at a vacuum condition, on which covers the cryo-cooler is mounted.

Abstract: Measuring system constituted by a radiation detection circuit (3) welded to a reading circuit (2) by metal members (4), which is itself welded to a grooved cover (9) by other metal members (19). The cover (9) is placed on a cryostat cold finger (1) and a cavity (6, 10) contains the two circuits (2, 3). This arrangement obviates the need for bonding and welding electrical connection wires and therefore simplifies assembly, alignment and parallelism of the different parts.