The present state of development of germanium and InGaAs/InP avalanche photodiodes and InGaAs PIN-FET receivers for 1.3 and 1.55 μm wavelength digital optical fibre systems is reviewed. The design parameters, device structures and performance limitations of these components are discussed and the receiver sensitivities that have been achieved in practice are compared.

Recent developments on a germanium avalanche photodiode (Ge-APD) and an InP/InGaAs-APD with a planar structure are described. The Ge-APD with a wide depletion layer had improved quantum efficiency and response speed at 1.55 μm wavelength. Transmission experiment using the Ge-APD showed 2 to 4 dB improvement in the minimum average received power yielding 10-9 error rate. A planar InP/InGaAs-APD with separated multiplication and absorption regions was fabricated by using a new technique for forming a guard ring. The guard ring junction was realized by Cd diffusion through a thin Si02 film. A low surface impurity density and linearly-graded junction were obtained by tie diffusion technique. A uniform multiplication gain of over 30 was achieved in the sensitive area.

Device structure parameters governing APD performances are discussed and optimum conditions are elucidated for both Ge APDs and heterostructure InGaAs APDs. Two types of Ge APDs with p+n and p+nn- structures were developed for use in 1.0 ~ 1.55 um wavelength. The dark current of Ge APDs was reduced to improve detection sensitivity by newly developed processes. Heterojunction InGaAs APDs were developed, which are formed in a top window type planar structure with an InP cap. Avalanche gain of about 30 and low dark current density of about 2 x 10-5A/cm2 at 0.9VB were obtained. High bit-rate operation was achieved at 450Mb/s.

The particular Cd0.7 Hg0.3Te band structure:almost equality of band gap and spin orbit splitting, provides good ionization properties to this alloy : a high ionization coefficients ratio is expected. The devices elaboration is made by planar technology. A N+/N/P+ structure is achieved by ions implantation followed by a diffusion process. A diffused guard ring allows to avoid surface and junction edge effects. The I (V) characteristic shows a breakdown voltage (VB) of about 100 V. The dark current at 0.95 VB, amounts 100nA.Photodiodes sensitivity is typiclly of 0.7. A/W when M=1.Multiplication coefficients as high as 40 have been measured, the photoresponse spatial homogeneity in gain mode has been also controlled with a lOμm size spot : no microplasma effect have been observed. Photodetectors sensitivity, measured at 500 MHz, remains identical in avalanche operating mode. Good linearity is obtained when plotting P-N schottky noise versus light intensity No excess noise was observed. The study of the avalanche photodiode noise, synchronous with 1.3. μm DEL emission, at 30 MHz with a 1 MHz bandwith has been carried out in relation to the multiplication factor, and has led to an estimation of the ionization coefficient ratio.

Silicon PπPN avalanche photodiodes with fiber pigtails (type CG 5705 FB2) have been submitted to qualification testing in order to evaluate simultaneously the performance of the crystal and the optical output fiber under extreme environmental and operational conditions. Electrical and optical results obtained demonstrate excellent performance of the photodetectors during the qualification testing and prove their suitability for telecommunication equipment.

High frequency wavelength modulation spectroscopy with diode lasers is accomplished by dithering the drive current at RF frequencies between 10 and 250 MHz. This technique is useful for fast and sensitive detection of absorption lines and is applied for fast reading of information from a frequency domain optical memory based upon photochemical hole burning.

The most rapid technical and industrial development in electroptics are now in the fields of optical telecommunications and infrared imaging. The evolution towards the infrared regions (0.8 μm then 1.3 μm and 1.55 μm) of spectral windows used in fiber telecommunications bring them nearer and nearer. Therefore and specially as far as detection functions are concerned parallels very useful in both directions, can be drawn between imagery ans telecommunications. These parallels will be analyzed herein from a fundamental point of view as well as technical and industrial, an interesting example will particularly be studied:the case of HgCdTe technologies that allow to cover both fields from the same semi-conductor.

HgCdTe focal plane arrays (FPA) have been fabricated for use in an Imaging Spectrometer instrument developed by the Jet Propulsion Laboratory for NASA. Imaging Spectrometer, developed for earth remote sensing applications, provides simultaneous imaging in 100 or more spectral bands. This is achieved by placing an area FPA at the focus of a spectrom-eter. The resultant instrument performs as a pushbroom imager with one axis of the focal plane corresponding to spatial information, and the other axis to spectral information. FPA requirements for current imaging spectrometer designs are discussed. A backside-illuminated hybrid FPA architecture which uses HgCdTe photovoltaic detectors interfaced to a Si CCD multiplexer is presented. HgCdTe material is grown by liquid phase epitaxy on CdTe. The detectors are planar, ion implanted junctions on 68 micron centers. 32 x 32 FPAs have been fabricated from this material for use in the 1 - 4.5 micron and in the 1 - 2.4 micron (short wavelength infrared or SWIR) spectral regions. Complete electro-optical characterization has been done in conditions expected in actual operation. The SWIR FPAs have been evaluated at temperatures of 120 - 150K in backgrounds of 1 x 1012 ph/cm2-s to 5 x 1013 ph/cm2-s. Peak quantum efficiency of the arrays is near 70% with excellent uniformity. Broadband spectral response to 1 micron has been achieved by proper epitaxial layer thickness on these backside-illuminated devices. Near background limited performance has been achieved for over 98% of the detectors.

This paper describes a new configuration for a Schottky barrier IRCCD (SB-IRCCD). This device utilizes a Meander Channel CCD (MCCD) for both the vertical and horizontal readout registers. The MCCD has simple electrode configuration consisting of two straight gate electrodes over the meander channel without bus lines and contact holes. This simple electrode configuration increases the fill factor of SB-IRCCD and results in the improvement of its photoresponse. In addition, the versatile electrode configuration of the MCCD simplifies connection (in corner turns) between the vertical and horizontal readout registers. A 64 x 64-element monolithic Schottky barrier infrared meander channel CCD (SB-IRMCCD) with a 23 % fill factor was fabricated with a relaxed 10 μm design rule. This paper also discuss how a fill factor of 57 % will be possible by decreasing the area of the vertical MCCD register to 30 % of the present device.

We present in this paper the performance of a linear array of 30 InSb 3-5 μm detectors multiplexed by a silicon CCD. The InSb detectors are photodiodes built on a p type InSb bulk substrate. The detector technololgy has been specially adapted for multiplexing detectors by n channel CCD's. The InSb detectors have a near-BLIP performance, are highly uniform and do not show any 1/f noise when reverse biased. The InSb array has been multiplexed in the focal plane by a n - channel CCD. The mean detectivity measured at the CCD output is 1.6 x 1011 cm W-1 Hz1/2. The photoresponse nonuniformity is smaller than ± 5 % and the dynamic range is 75 dB. The limiting factors of these kinds of arrays will be discussed.

"Since the mid 1970's focal plane array technologies have been investigated to develop prototypes for a new generation of high sensitivity infra red equipements such as thermal imaging and surveillance systems and missile seekers. These technologies involve to use new design rules in the system conceptiontrade off between state of the art in detector and processing electronic technology, optics, cryogenic and mecanical constraints should be made. In this paper we develop our ideas on system design using focal plane arrays both in 3-5 microns and in 8-10 microns wavelength ranges : focal plane architectural design (scanning versus starring), new optical concept to reduce the backround photon flux, frame averager, digital or analog signal processing in image restoration. Some examples based on our experiences in this field are given".

A novel optical technique for improving the performance of focal plane staring arrays by increasing the fill factor ratio is described. The specific mosaics considered are 64 x 32 and 128 x 64 arrays of infrared detectors with charge coupled devices (IRCCD) made from monolithic silicon. The video enhancement is accomplished by means of a refracting silicon faceplate that redirects focused image irradiance from nonsensitive CCD areas to the infrared detector elements. Operational theory and design parameters for this unique faceplate construction are detailed. With the optimum faceplate configuration installed at the IRCCD front surface, a sensitivity increase of at least 150 percent is predicted from the analysis presented here.

The use of pyroelectric materials and devices in infrared imaging cameras is now a well established technology. The pyroelectric vidicon camera tube has given rise to a range of inexpensive thermal imagers which operate at ambient temperatures, without a requirement for cooling, and are suitable for all but the most demanding roles. The pyroelectric retina of the camera tube is equivalent to a large two dimensional array of detector elements which is addressed and read out by the electron beam. Because of this large number of equivalent elements, in excess of 5 104, the moderate detectivity of the pyroelectric detector is enabled to image temperature differences in the scene down to less than 1°C. In recent research, the attention has turned to solid state readout of large pyroelectric detector arrays and in particular to the possibility of interfacing the pyroelectric array directly with a silicon chip. The aim is to improve both the discrimination of scene temperature and also the physical characteristics such as size, power requirements and ruggedisation. Devices comprising from several hundred detectors up to many thousands in various two-dimensional formats are of immediate interest.

In order to overcome bonding and packaging problems associated with two dimensional arrays of large numbers of elements, a pyroelectric/CCD hybrid is being developed. The device consists of a 256 element two dimensional pyroelectric array directly bonded to a custom CCD. The monolithic pyroelectric array is made of a modified lead zirconate ceramic with element size 216μm square on a 256μm pitch. The CCD incorporates sixteen rows of sixteen element analogue multiplexers. Direct charge injection into the CCD channel is achieved via an array of pads on the top of the CCD which are bonded directly to the pyroelectric, currently with an array of screen printed epoxy resin dots. A solder bonding technique is preferred, but is still under development. The detector array is intended to be used with a mechanical chopper operating at approximately 50Hz frame rate. Devices are tested in a compact camera and display system. Prototype devices have been made with more than 200 working elements and NETD measurements on single elements give results between 1°C and 2°C. The theoretically predicted value is 0.8°C.

A palladium silicide (Pd2Si) Schottky barrier sensor for satellite push-broom multispectral imaging in the 1-3.5 μm short wavelength infrared (SWIR) is being developed. The SWIR sensor will utilize Schottky barrier infrared charge-coupled device (IRCCD) technology to realize dual-band integrated circuits with two linear arrays of 512 detectors each. The monolithic, two-color devices will have 30-μm center-to-center detector spacing and an 80 to 90% fill-factor. These integrated circuits will be suitable for chip-to-chip abutment, thus providing the capability to produce large, multiple-chip focal planes with contiguous, in-line detectors. To date, monolithic 32-x-64 and 64-x-128 palladium silicide interline transfer IRCCDs have been developed. These silicon imagers exhibit a low response nonuniformity of typically 0.2 to 1.6% rms. Spectral response measurements of Pd2Si p-type Si devices yield quantum efficiencies of 7.9% at 1.25 μm, 5.6% at 1.65 μm, and 2.2% at 2.22 μm. Improvement in quantum efficiency is expected by optimizing the different structural parameters of the Pd2Si detectors. The dark current level of Pd2Si detectors permits radiometric operation at 120-125K with a measured dark current of 2 nA/cm2 (120K). This operating temperature is complemented by a low power dissipation of 18 μW per detector for nominal operation of a push-broom 2-x-512 device. These operational parameters will permit the realization of satellite-borne, passively cooled, dual-band focal planes with thousands of detector elements. It has been shown that the performance of the technology will permit the dual-band sensor to meet the noise-equivalent-delta reflectivity (NEAp) requirements for accurate classification of earth resources features.

An advanced airborne pushbroom scanner, MEIS II, has been developed and operated by the Canada Centre for Remote Sensing. The imaging scanner uses charge-coupled device linear array detectors, and covers the near infrared and visible spectral regions, spectral bands being readily selected by means of optical filters. MEIS II has a low noise equivalent radiance and high spatial resolution, and its real-time data processor provides radiometric gain and offset corrections, together with geometric and aircraft roll compensation. The sensor shows an improvement in noise equivalent radiance of at least two orders of magnitude when compared to the rotating-mirror scanner presently in use at CCRS as well as improvements in the geometric fidelity and spatial measurements, with inter-channel registration to within a fraction of a pixel.

Potential astronomical applications of two-dimensional arrays of infrared detectors are reviewed for ground based and for space observations.

In recent years there have been rapid advances in infrared television cameras based upon metal-silicide focal plane arrays. These devices sense infrared via internal photo-emission of hot carriers a process that is analogous to vacuum photoemission. Internal photoemission is very reproducible and large arrays with cell to cell photoresponse uniformity better than 0.5% rms have been demonstrated. This uniformity has been exploited in the design of simplified cameras which require minimal pixel compensation. Projected applications of these cameras include medical diagnostics, reliability studies and infrared astronomy. The present paper will describe the development of the silicide camera technology, outline the physics of camera operation and demonstrate preliminary imagery in astronomy and thermal diagnostics.

In the years 1985-90, satellites equipped with push-broom instruments will provide 20 m resolution images over three visible and near infrared wavelenghts, and panchromatic 10 m resolution images. These are the "Satellites Probatoires d'Observations de la Terre" (SPOT), i.e. Experimental Remote Sensing Satellites of the french earth resources monitoring program. For the following period (1990-2000), this service can be improved in various ways, particularly by adding two SWIR channels centered on 1.65 and 2.2 micrometers and registered with the visible and near infrared channels. This paper shows the expected characteristics of the SWIR detectors, which are suitable for an instrument originating from that of SPOT, and also the procedure leading to the values proposed. The last paragraph gives a few examples of technologies that can be used (detector pattern, multiplex, cooling).

Highly sensitive extrinsic infrared detectors for infrared astronomy in space have been developed at Battelle-Institut e.V., Frankfurt am Main, on behalf of the West German Government (BMFT) and the European Space Agency (ESA). In this paper we will discuss the present status of the performance data of our Si:P and Ge:Be detectors, which feature maximum sensitivity in the wavelength interval from 25 μm to 50 μm. Application of these detectors in the GIRL project (German Infrared Laboratory, to be launched on Spacelab) is being considered. The noise equivalent power (NEP) test data at the photon background flux density expected for this application (≈108 phot/cm2s) are NEP (40 μm, 10 Hz, 3 K) = 8x10-17 W/√Hz (Ge:Be) and NEP (26 μm, 10 Hz, 10 K) = 4x10-17 W/√Hz (Si:P). The cryogenic preamplification will also be discussed briefly.

The Near-Infrared Mapping Spectrometer (NIMS) is one of the science instruments in the Galileo Mission, which will explore Jupiter and its satellites in the late-1980's. The NIMS experiment will map geological units on the surfaces of the Jovian satellites, characterize their mineral content; and for the atmosphere of Jupiter, investigate cloud properties and the spatial and temporal variability of molecular abundances. All the optics are gold-coated reflective and consist of a telescope and a grating spectrometer. The balance of the instrument includes a 17-detector (silicon and indium antimonide) focal plane array, a tuning fork chopper, microprocessor-controlled electronics, and a passive radiative cooler. A wobbling secondary mirror in the telescope provides 20 pixels in one dimension of spatial scanning in a pushbroom mode, with 0.5 mr x 0.5 mr instantaneous field of view. The spectral range is 0.7 - 5.2μ resolution is 0.025μ. NIMS is the first infrared experiment to combine both spatial and spectral mapping capability in one instrument.

Each of the two telescopes of the Infrared Heterodyne Interferometer ( 11 microns) at CERGA is equiped with a near infrared ( 2 microns) imaging system using InSb photodiode and the multiplex encoding technique. Finding an astronomical source and guiding the telescope is made easier by real-time imaging of the 40 x 40 Arcsec2 field ( resolution 32 x 32). Such a system is of full interest for daytime pointing as well as pointing on purely infrared objects. In addition, a permanent correction of turbulence-induced random mispointing is performed. After a brief reminding of the principle, the system is described and the actual as well as the potential capabilities are given.

The design of a hybrid circuit frequency compensation module for use with various infrared instrumentation systems is discussed. The design objective is to achieve essentially the same preamplifier response over a given range of frequencies both at high-level output and at low-level output, when operating at the same temperature as a cryogenic sensor (detector). The design procedure requires that the temperature and/or voltage variation of resistor values used in the module be either (a) measured directly or (b) extracted from comparison of measured and computer-generated frequency response curves. It is found that a computer-aided design procedure using iterative analysis with an ac network analysis program results in reduced design and development time. Also, this procedure leads to a better understanding of problems associated with cryogenic sensor-amplifier interfaces.

Earth Observation from Space calls for new sensors with ever improved performances afforded by advanced technology. The recent concepts of space-borne optical imagers are for most of them based on the push-broom imaging principle whereby each line of the image is electronically scanned by an array of integrated solid-state detectors. The deployment of the push-broom principle in the visible part of the spectrum has come recently in the realm, as illustrated by the SPOT-HRV camera, the German MOMS or the Japanese MOS-1 instrument which represent second generation in space optical instrumentation for Earth observation. The advent of multi-element, self-scanned arrays or IR detectors makes it feasible to extrapolate the push-broom concept towards short, medium and longwavelength infrared, since observation in these bands is highly desirable to complement visible, near IR imagery. However, practical implementation on a space platform entails specific constraints which are sometimes overlooked. More specifically, the potential dwell time advantage afforded by the electronically scanned arrays over the discrete detectors used in conjunction with a mechanical scanner cannot be easily exploited in several cases. This paper emphazises on the most critical difficulties to be overcome, namely interfacing with optics, cooling of large detector arrays, signal processing requirements and in-flight calibration. Suitability of existing devices is discussed with respect to the presently foreseen space applications.

The ESO Infrared Photometer/Spectrophotometers are at present in use on the 3.6 m and 1 m telescopes at our observatory at La Silla in Chile. Each instrument consists of a photometer mount and two detector units, a solid N2 cooled (~55°K) InSb detector for the 1-5 μm region and a bolometer, for the 2-25 μm region, which is cooled to ~l.2°K by pumping on liquid helium. Early next year, two new photometer mounts will be installed on the 2.2 m and on the 3.6 m telescopes, both using an f/35 chopping secondary mirror. The detector units are mechanically and optically identical for these 4 instruments in order to facilitate their operation and maintenance at the observatory. A description of the detector units follows.

A 52 Element InSb Array will be used at ESO for infrared spectrocopy in the 1-5μm region. This array is one of the largest linear arrays ever used in astronomical spectrometers. Tests on this array, carried out in the laboratory, will be demonstrated and first results will be presented. The electronic implications for such an array are described.

The equations used for system infrared calculations are presented. These equations are then rearranged into the forms useful for developing space infrared systems. In the paper, curves and nomograms are presented that exhibit the relationships between many parameters such as detector sizes, diameter of the optics, focal lengths of the optics, ground footprint, D* , angular resolution, target intensity, and quantum efficency

During recent years civil application of thermography in Germany has experienced a remarkable development in general but especially in the building trade. On the one hand there was an increase of user-oriented know-how,and on the other hand a growing public knowledge and acceptance mainly induced by a lot of governmental and commercial publications on energy conservation. From a practical viewpoint a description of interesting possibilities but also narrow limitations of four present-day application areas is given : 1. scanning of buildings from inside and outside - for fault analysis and all kinds of expertises including popular energy conservation consulting 2. mapping of plastered half-timbered houses (constructed in 13.-17. century, plastered in some parts of germany in 18. and 19. century) - for renovation and re-establishment of original historical shape 3. visualization of reinforcement in concrete for careful hole-drilling In large structures f.i. nuclear power plants according to safety regulations 4. localization of leakages in floor heating and tap water systems - for cost effective repair and status reports, mainly by order of insurance-companies.

The spot radiometer is a non-imaging, infrared instrument designed to measure either the temperature of a well-defined surface area or the radiosity from that area. (Radiosity is defined as the total radiation which leaves a surface per unit time per unit area, and is the sum of emitted and reflected radiation.) Typically, the Spot Radiometer is a portable, battery-operated device consisting of a collecting lens or mirror, an infrared detector, an amplifier, signal processor circuitry, and an analog or digital display.

The interfacing of a new type of integrating infrared detector to an analog-to-digital converter is described, and the results of experimental tests of the complete system are presented. The detector utilizes charge storage in impurity levels rather than in potential wells associated with the device architecture. The amount of stored charge depends on the total integrated IR flux on the detector during an exposure. The stored charge is sensed by applying a readout pulse which ejects charge from the impurities by a quantum mechanical process. A greater IR flux results in less charge being sensed during a readout operation. After readout, a detector reset pulse is used to inject and restore charge in the impurity levels. Sensing of charge on readout is accomplished by an FET preamplifier. The signal is amplified and fed to a gated integrator whose output is digitized by a successive approximation analog to digital converter. Data is accumulated in a Hewlett-Packard minicomputer. Integration times from milliseconds to hours have been used in our tests, but a much wider range is possible. The detector doesn't consume any power during integration. Tests of the system usingblackbody sources have demonstrated a capability to detect a very wide range (2 x 106) of IR intensities. Possible applications will be discussed.

C.S.E.E. has marketed for the last twenty years, a series of hot axle-box detectors for trains. The essential element in this equipment is the sensing head which collects the infra-red rays issuing from the axle-boxes and converts them into an electrical signal. The lecture will describe the solutions that have been established in order to create a sensible and viable item of precision equipment, whilst taking into account the necessary constraints due to the railway environment and the technology available at the given epoque.

Infrared-sensors are used in medicine to detect the temperature of the skin. The temperature distribution over the human skin surface gives insight into many physiological problems concerned with thermoregulation and metabolism. Skin temperature patterns in dermatologic, vascular, locomotor and malignant diseases can provide valuable information for clinical diagnosis and therapeutic assessment. Skin temperature can be measured accurately by several means. Infrared thermography can register overall skin temperature and its distribution comprehensively. This noninvasive, no-touch technique is the measurement of skin surface temperature by the emission of heat energy in the infrared portion of the spectrum, with the human skin being an excellent black body radiator. The physical conditions of the skin and the environment are important when determining skin temperature with infrared-sensors. The thermal imaging system has to produce a high quality thermal picture of the skin within a short observation time. The processing of thermographic images by computer methods offers the promise of improving and enhancing the utility of thermography as an clinical and research instrument.

Infrared line scan detection is a thermal mapping method particularly suitable to point out defects in non-destructive testing and for process monitoring control. Infrared systems designed for this type of application must show high performances, 24-hour self-operating as well as low cost. Thermo-electrically cooled infrared detector technology makes it possible to reach this goal. The digital signal generated by the optical scanning head is transmitted by means of optical fibers to the processing unit for industrial process control.

Today infrared techniques have a wide variety of applications in both fire and intrusion alarm systems. Pyroelectric sensors are used in both flame detectors and passive infrared intruder alarms to sense the infrared emission of open flames and the blackbody radiation of human targets, respectively. In this paper we discuss the different applications and demonstrate the impact of the sensor technology on the system performance. It can be shown that in order to get an optimum detector an independent optimization of sensor technology and signal processing is not possible but that the two areas have to be optimized as a whole system.

The rapidly expanding market for pyroelectric detectors in passive infra-red intruder alarms does not call for high performance detectors in the conventional sense, but nevertheless places requirements on the detector which are very demanding in terms of consistency of product and long term reliability. This paper examines some of the areas of interaction between the system requirement and the detector design and highlights the parameters of importance and the ways in which these are achieved in a large volume production environment. Future market trends and the impact on detector design are also discussed.

The problem of false alarms is defined showing the demanding nature of the application. Detector dependencies are discussed relative to reliability, such as: pyroelectric material, possible depolarization, long term stability, use of separate load resistors to achieve predictable time constants, response to temperature changes, soft error rate, potential microphonics, and the need for EMI protection. Highest reliability of the circuit design involves consideration of the internal FET of the detector as well as careful selection of coupling capacitors, resistors and the power supply. The detector signal's dependence on optical design is identified and the relationship of signal-to-noise specified. User handling precautions of the detector are also given. Appendices show 1) the relationship of S/N ratio to false alarm rate in Gaussian terms, 2) failure rates of alarm components, 3) evaluation of approaches to testing, and 4) a brief discussion of soft error mechanisms.

A thermal image of the human body is not a simple concept. The human body is a complex homeotherm, producing heat that must be lost into the environment. Human skin is the dynamic organ which serves as an interface between the body core and environment. Its temperature is therefore influenced by both internal and external conditions. Man is constantly changing his physical and physiological demands throughout his conscious hours. Local skin temperature is therefore influenced by air temperature, humidity, the presence of clothing, and a host of internal influences. Heat flow by conduction from underlying organs and blood convection in particular, warm the skin by the transfer of heat from the core. Changes in blood flow frequently occur, and contribute to the constant demand for thermal equilibrium.

Locomotor diseases is a wide range of about 450 different illnesses with all different pathologies, clinical and prognostic features and response to treatment. No single method will be able to cover the whole spectrum of local and systemic signs and symptoms. Nevertheless there is a need for objective measurements at the site of disease: clinical examination is often enough depending from subjective estimations and personal experiance of the clinician. Laboratory tests only show the systemic effect of the disease, like inflammation. X-rays are restricted to the detection of structural changes appearing late during the pathological process, even when using different techniques. Here IRT offers several advantages to the clinician as well as to the patient. As a non invasive method it monitors the course of disease at the anatomic site of pathology. Quantitative figures calculated from the thermogram,either taken at steady-state or during dynamic tests, are essential for differential diagnosis and follow-up. Advanced IRT camera systems fulfill all requirements set up for medical thermography recently by the National Bureau of Standards. Although, the user should check his system daily with regard to precision of absolute temperature measurements. Standardisation of recording technique is essential as well,to get reliable results. Ambient conditions must be adapted to the locomotor disease pathology under study. Advanced IRT systems , e.g. ZEISS-IKOTHERM, together with image processing capability and special software, e.g. THERMOTOM package, are valuable tools to the rheumatologist for diagnosing and monitoring locomotor diseases.

Pyroelectric ceramics offer a number of advantages over single crystal materials for use in infra-red detectors. This paper discusses these advantages and describes the development of hot-pressed ceramic compositions within the PbZr03-Pb2FeNb06-PbTiO3 system and the control of their relevant electrical properties by doping with uranium oxide.

Cd1-xMnxS is a new family of semiconducting compounds which show good photoresponse in the visible region. Observed photoresponse curves show that the maxima change between 625 nm to 650 nm as x varies from 0.1 to 0.4. This allows the selection of the spectral response according to technological requirements. Before further applications towards photodetection, the growth techniques for these crystals needs to be improved to guarantee the reproductivity and homogeneity of these materials.