Modern Photodetector IR-Modules

Journal of Communications Technology and Electronics - In recent years, there has been a rapid improvement in photonics products due to the use of multilayer heterostructures grown on the basis of...     

Single and matrix HgCdTe photovoltaic detectors

The recent researches and technological developments of middle and long wavelength infrared HgCdTe photovoltaic detectors are presented. Structure, topology, design and performance of HgCdTe photodiodes, silicon readout electronics, Focal Plane Arrays both staring and time delay and integration types, thermal imagers are discussed. Negative differential conductance, bistability and high frequency oscillations under background infrared radiation in HgCdTe photodiodes are reported.     

Solid-state photoelectronics of the ultraviolet range (Review)

The state-of-the-art of the development of photodetectors and photoreceiving devices operating in the range of electromagnetic radiation 0.1–0.38 μm is presented. A review of the world achievements and tendencies in the development of this field of photoelectronics based on various semiconducting materials is presented. Main physical and engineering problems of the development of ultraviolet photodetector modules designed on the basis of the А^III-N compounds are considered.     

Analytical model used to calculate focal-plane-array parameters

The theory making it possible to rather accurately predict a complete set of characteristics (signals, noises, and photoelectric parameters) inherent to all components of the photodiode-based focal plane array (FPA) under design and optimize its parameters has been developed. The theory relies on a new approach to the determination of FPA irradiance, which ensures its calculations at any shape of the diaphragm in the light-insulating shield. Both staring and scanning FPAs, the latter of which operate under the condition of time delay and accumulation, are discussed. The theory has been verified using a 320 × 256 FPA. The calculated dependences of the signals and noises of photoelectric components are compared with the experimental values obtained at different accumulation times and background irradiation temperatures. The theoretical data are revealed to be in complete agreement with the experiment, confirming the model validity. The theory will be undoubtedly useful for designers, manufacturers, and users of FPAs. The model can easily be extended to systems with FPAs.     

Photoelectric characteristics of focal plane arrays based on epitaxial layers of indium antimonide deposited on a heavily doped substrate

Photoelectric characteristics of a 320 × 256-element focal plane array (FPA) with a pitch of 30 μm, whose photosensitive element is formed in the InSb epitaxial layer deposited on a heavily doped substrate, have been investigated. For a relative aperture of 1: 0.94 and an integration time of 1.46 ms, the mean value of the noise-equivalent temperature difference is 10.5 mK, the percentage of defective elements is 0.12%, and the correction time is more than 3 h. The FPA has been compared to similar commercial devices based on bulk InSb.     

Energy-Saving Technology of Assorted Glassware Decoration by Plasma Spraying

Glass and Ceramics - An energy-saving technology for decorating assorted glassware by plasma spraying of colored assorted and container glasses was developed. The optimal spraying parameters for...     

Long-Wave Infrared Focal Plane Arrays Based on a Quantum-Well AlGaAs/GaAs Structure with 384 × 288 Elements

The characteristics of focal plane arrays (FPAs) based on (quantum-well infrared photodetector) QWIP structures with 384 × 288 elements spaced at the intervals 25 μm are investigated. The difference in spectral and current–voltage characteristics is established for epitaxial QWIP wafers. The output signal is found to vary over the area of photosensitive elements with gradients in different directions. The photoelectric FPA parameters depend strongly on the temperature of the cooled assembly and the bias at the photosensitive element. The noise-equivalent temperature difference is 30 mK at the frame rate 120 Hz and the cooled assembly temperature 65 K.     

Experience with uranium-erbium fuel at the Ignalinsk Atimic Power Plant

Conclusions Experience with uranium-erbium fuel assemblies at the Ignalinsk Atomic Power Plant confirms the possibility of removing additional absorbers and considerably increasing the depth of fuel burnup, while maintaining permissible values of the steam reactivity and other characteristics important for reactor safety. Conversion of the reactor to uranium-erbium fuel permits not only the maintenance of α_ϕ within specified limits but also compensation for its growth on account of replacement of the control rods. The effectiveness of uranium-erbium fuel up to degrees of burnup close to the design value (∼20 MW·day/kg) has been demonstrated. The good agreement of the theoretical predictions and the actual characteristics offers hope that the complete conversion of reactors to uranium-erbium fuel and appropriate removal of additional absorbers will yield high fuel burnup and considerable improvement in the economic performance of atomic power plants. Other means of increasing the fuel burnup in RBMK-1500 reactors might be to increase the fuel enrichment and erbium content, to use zirconium spacers, and to reduce the operational reserve of reactivity. Ignalinsk Atomic Power Plant. Kurchatovskii Institute Russian Scientific Center. Mashinostroitel'nyi Zavod Joint Stock Company. Scientific-Research and Design Institute of Energy Technology. A. A. Bochvar All-Russian Scientific-Research Institute of Nonferrous Materials. Translated from Atomnaya énergiya, Vol. 85, No. 2, pp. 91–97, August, 1998.     

Optical monitoring of characteristics of the stratospheric aerosol layer and total ozone content at the Siberian Lidar Station (Tomsk: 56° 30′ N; 85° E)

We consider the results of long-term remote optical monitoring obtained at the Siberian Lidar Station of Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences, Tomsk (56° 30′ N, 85° E). The scattering characteristics of stratospheric aerosol layer, obtained according to data of lidar measurements recorded since 1986, are presented. We analyse the trends of changes in the total ozone (TO) content over Tomsk for the period 1996–2013 according to data of spectrophotometric measurements employing Total Ozone Mapping Spectrometer (TOMS) data for the period 1979–1994. We determined the periods of elevated content of stratospheric aerosol over Tomsk after a series of explosive eruptions of volcanoes in the Pacific Ring of Fire and Iceland in 2006–2011. Since the second half of the 1990s we have recorded an increasing TO trend, equalling 0.65 DU/year for the period 1996–2013.     

Ten years (1986–1995) of lidar observations of temporal and vertical structure of stratospheric aerosols over Siberia

The data of laser sensing of the vertical aerosol distribution obtained at Siberian Lidar Station of the Institute of Atmospheric Optics, Tomsk (56.5°N, 85.1°E), Russia in 1986–1995 are analyzed. The data are presented in the form of the scattering ratio R(H), the aerosol backscattering coefficient β^a_π(H), and the integrated aerosol backscattering coefficient between 15 and 30 km Σβ^a_π at the wavelength λ=532 nm. During the period from summer 1986 to summer 1991, Σβ^a_π varied in the range 0.8×10^-4–3×10^-4 sr^-1. Average profiles of R(H) and β^a_π(H) for the main seasons, the annual behaviour of the altitude of the peak scattering ratio and of the tropopause height, and the eigenvectors of the correlation matrix of R(H) are also presented for this period. In succeeding years, the behavior of the stratospheric aerosol layer (SAL) was primarily determined by the Pinatubo volcanic aerosol. Based on an analysis of the scattering ratio profiles, the formation of the vertical volcanic aerosol stratification above Tomsk is demonstrated. The maximum values of Σβ^a_π≈4×10^-3 sr^-1, caused by the volcanic aerosol, were observed in January–February 1992. Between 15 and 30 km, the 1/e-decay time of the stratospheric volcanic aerosol was 357±37 days. Lidar measurements carried out on certain days simultaneously at λ=532, 353, and 628 nm allowed us to investigate the transformation of the exponent A(H) that characterizes the spectral dependence of the volcanic aerosol backscattering coefficient in the wavelength range 353–532 nm and to estimate the geometric cross section of particles S(r).