Active-edge planar radiation sensors

Many systems in medicine, biology, high-energy physics, and astrophysics require large area radiation sensors. In most of these applications, minimizing the amount of dead area or dead material is crucial. We have developed a new type of silicon radiation sensor in which the device is active to within a few microns of the mechanical edge. Their perimeter is made by a plasma etcher rather than a diamond saw. Their edges can be defined and also passivated by growing, in an intermediate step, a field oxide on the side surfaces. In this paper, the basic architecture and results from a synchrotron beam test are presented.     

Certification method for standard thermoresistive voltage transducers

Translated from Izmeritel'naya Tekhnika, No. 2, pp. 25–27, February, 1989.     

Security of solar radiation management geoengineering

Solar Radiation Management (SRM) geoengineering is a proposed response to anthropogenic global warming (AGW) (National Academy of Sciences, 2015). There may be profound – even violent – disagreement on preferred temperature. SRM disruption risks dangerous temperature rise (termination shock). Concentrating on aircraft-delivered Stratospheric Aerosol Injection (SAI), we appraise threats to SRM and defense methodologies. Civil protest and minor cyberattacks are almost inevitable but are manageable (unless state-sponsored). Overt military attacks are more disruptive, but unlikely – although superpowers’ symbolic overt attacks may deter SRM. Unattributable attacks are likely, and mandate use of widely-available weapons. Risks from unsophisticated weapons are therefore higher. An extended supply chain is more vulnerable than a secure airbase – necessitating supply-chain hardening. Recommendations to improve SRM resilience include heterogeneous operations from diverse, secure, well-stocked bases (possibly ocean islands or aircraft carriers); and avoidance of single-point-of-failure risks (e.g. balloons). A distributed, civilian-operated system offers an alternative strategy. A multilateral, consensual SRM approach reduces likely attack triggers.     

Semiconductor film thermoelectric elements as radiation temperature sensors

The sensitivity is calculated for a thermoelectric unit used as a radiation temperature sensor in a null method.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 20, No. 4, pp. 633–641, April. 1971.     

Effect of solar radiation on human head

The paper concerns the use of an analytical model to study the effect of solar radiation on a human-sized head. Considering spherical geometry, the braincase is taken to be consisted of two layers, one representing the scalp and the other the skull. The material of each layer is assumed to be elastic and transversely isotropic. The applicability of the model is illustrated through the computation of the stress-field in the scalp as well as in the skull.     

Galactic and solar radiation exposure to aircrew during a solar cycle

An on-going investigation using a tissue-equivalent proportional counter (TEPC) has been carried out to measure the ambient dose equivalent rate of the cosmic radiation exposure of aircrew during a solar cycle. A semi-empirical model has been derived from these data to allow for the interpolation of the dose rate for any global position. The model has been extended to an altitude of up to 32 km with further measurements made on board aircraft and several balloon flights. The effects of changing solar modulation during the solar cycle are characterised by correlating the dose rate data to different solar potential models. Through integration of the dose-rate function over a great circle flight path or between given waypoints, a Predictive Code for Aircrew Radiation Exposure (PCAIRE) has been further developed for estimation of the route dose from galactic cosmic radiation exposure. This estimate is provided in units of ambient dose equivalent as well as effective dose, based on E/H x (10) scaling functions as determined from transport code calculations with LUIN and FLUKA. This experimentally based treatment has also been compared with the CARI-6 and EPCARD codes that are derived solely from theoretical transport calculations. Using TEPC measurements taken aboard the International Space Station, ground based neutron monitoring, GOES satellite data and transport code analysis, an empirical model has been further proposed for estimation of aircrew exposure during solar particle events. This model has been compared to results obtained during recent solar flare events.     

Low temperature silicon deposition for large area sensors and solar cells

Low temperature deposition methods are needed for realizing large area electronics on alternative substrates like glass, polymer or steel foils. Reasonable electronic quality of low temperature deposited silicon, however, can only be achieved by employing additional, non-thermal sources of energy for promoting and optimizing the surface controlled silicon growth. Methods like very high frequency glow discharge or hot-wire chemical vapour deposition provide a wide range of control over the deposition process, enabling high growth rates, amorphous as well as crystalline silicon deposition and effective hydrogen etching. The current status of these deposition methods is reviewed and the resulting material properties are discussed. Applications like two-terminal colour sensors and photodiodes for retina implantation demonstrate the potential of joining amorphous and crystalline silicon technology into hybrid sensor systems and teach us how to use the building blocks for novel large area electronics.     

Characterization of supported cylinder-planar germanium waveguide sensors with synchrotron infrared radiation

Cylinder-planar Ge waveguides are being developed as evanescent-wave sensors for chemical microanalysis. The only non-planar surface is a cylinder section having a 300-mm radius of curvature. This confers a symmetric taper, allowing for direct coupling into and out of the waveguide's 1-mm(2) end faces while obtaining multiple reflections at the central <30-microm-thick sensing region. Ray-optic calculations indicate that the propagation angle at the central minimum has a strong nonlinear dependence on both angle and vertical position of the input ray. This results in rather inefficient coupling of input light into the off-axis modes that are most useful for evanescent-wave absorption spectroscopy. Mode-specific performance of the cylinder-planar waveguides has also been investigated experimentally. As compared to a blackbody source, the much greater brightness of synchrotron-generated infrared (IR) radiation allows a similar total energy throughput, but restricted to a smaller fraction of the allowed waveguide modes. However, such angle-selective excitation results in a strong oscillatory interference pattern in the transmission spectra. These spectral oscillations are the principal technical limitation on using synchrotron radiation to measure evanescent-wave absorption spectra with the thin waveguides.     

Double-cavity radiometer for high-flux density solar radiation measurements

A radiometric method has been developed, suitable for both total power and flux density profile measurement of concentrated solar radiation. The high-flux density radiation is collected by a first optical cavity, integrated, and driven to a second optical cavity, where, attenuated, it is measured by a conventional radiometer operating under a stationary irradiation regime. The attenuation factor is regulated by properly selecting the aperture areas in the two cavities. The radiometer has been calibrated by a pulsed solar simulator at concentration levels of hundreds of suns. An optical model and a ray-tracing study have also been developed and validated, by which the potentialities of the radiometer have been largely explored.     

Error in the thermoresistive sensor-based feedback measurementconfiguration due to DC amplifier offset voltage

Feedback circuits with thermoresistive sensors have been widely used in the measurement of thermal radiation and fluid flow. In general, the operation of these circuits is explained, assuming an ideal operational amplifier used in the feedback configuration. The effect of the operational amplifier offset voltage on the static performance has been analyzed. The error introduced when used as a measuring instrument, due to input offset voltage, is estimated     

Diurnal discrepancies in spectral solar UV radiation measurements

Unexpected diurnal discrepancies between high-quality spectroradiometers were observed during the 2000 Nordic Ozone Group Intercomparison campaign. The spectral ratios of the irradiances showed a diurnal variation of approximately 2-9%. This cannot be explained by the nonideal angular response of the instruments' input optics in one plane (cosine effect). Instead, by using a radiative transfer model, we show that differences in the angular response in four azimuth planes have the potential to bias the measured data by up to 4.4% (azimuth effect). Other relevant factors are also discussed and quantified and are shown to be significant when diurnal changes in radiation are explained by environmental factors, or when measured data are compared with model or satellite data. Again, intercomparison campaigns have the potential to reveal errors that would otherwise remain undetected.     

考虑太阳辐射的轿车客舱流场与温度场的数值计算

对轿车室内的热环境进行了数值模拟。计算采用SIMPLE算法,紊流采用k-ω模型,考虑了自然对流换热的影响,应用整体求解法计算气固耦合传热问题。采用射线追踪法计算了太阳热负荷,以图形的形式给出其在车内的分配情况,有利于直观地分析其对车内热环境的影响。CFD的计算结果表明,进、回风口的布置不仅影响车室内气流速度和温度的具体数值大小,而且决定了整个流场和温度场的分布结构。     

Radiative properties of snow for clear sky solar radiation

Spectral and integrated radiative properties (reflection, transmission, and the rate of heating) of finegrained wind-packed snow typical of subpolar regions are studied through a model taking into account surface reflection and volumetric multiple scattering. The surface reflection is modeled by a bidirectional reflectance distribution function applicable to powdered dielectric material. For the volumetric multiple scattering, the radiative transfer equation designed for strongly asymmetric scattering is solved. All multiple scattering parameters (single scattering albedo, various moments of the scattering phase function, and optical depth) are related to measurable physical characteristics (density, grain size, and the absorption coefficient of pure ice).Parameterized atmospheric spectral transmission coefficients for scattering and absorption by aerosols and gases are used to obtain the direct and diffuse components of solar flux, incident on the snow-cover. Calculated values of spectral and integrated visible and near infrared reflection and flux attenuation coefficients of snow are compared with observations. The rate of radiative heating at different depths within the snowcover is calculated from the net flux divergence. It is shown that the conventional method of calculating this rate using measured bulk extinction coefficients grossly underestimates the amount of heating within the top few millimeters. This study provides a better overall understanding of the radiative properties of snow under clear sky conditions in terms of the physical characteristics of the snowcover.     

Characterisation of SiC photo-detectors for solar UV radiation monitoring

Silicon carbide has a potential for solar UV radiation monitoring: extremely resistant to UV radiation damage, nearly-blind to visible and infrared radiation and less sensitive to temperature variations than standard radiometric systems. A radiometer composed by three SiC photodiodes has been designed, manufactured and tested under solar radiation. Two photodiodes are equipped with filters in the UVB (280-315 nm) and UVA (315-400 nm) ranges while a third is filtered to match the erythemal action spectrum. UVA, UVB components of the solar radiation as well as UV index (UVI) at the earth's surface have been determined in two site positions in Tuscany, Italy. Data as a function of day-light allowed us to evaluate total optical thickness for UVA and UVB: τ_UVA=0.46 and τ_UVB=1.8. UVI values measured during the year well compares with computed ones used for weather forecast procedures.     

Concentration of solar radiation by white backed photovoltaic panels

In this paper, we present an analysis of the concentration achieved by white backed photovoltaic panels. Concentration is due to the trapping by light scattered in the refractive plate to which the solar cell is bonded. Using the reciprocity relation and assuming the ideal case of a Lambertian distribution, a detailed model is formulated that includes the effects of the thickness and walls of the concentrator. This model converges to the thermodynamic limit and is found to be consistent with experimental results for a wide range of cell sizes. Finally, the model is generalized to multiple-cell photovoltaic panels.     

Exposure to galactic cosmic radiation and solar energetic particles

Several investigations of the radiation field at aircraft altitudes have been undertaken during solar cycle 23 which occurred in the period 1993-2003. The radiation field is produced by the passage of galactic cosmic rays and their nuclear reaction products as well as solar energetic particles through the Earth's atmosphere. Galactic cosmic rays reach a maximum intensity when the sun is least active and are at minimum intensity during solar maximum period. During solar maximum an increased number of coronal mass ejections and solar flares produce high energy solar particles which can also penetrate down to aircraft altitudes. It is found that the very complicated field resulting from these processes varies with altitude, latitude and stage of solar cycle. By employing several active and passive detectors, the whole range of radiation types and energies were encompassed. In-flight data was obtained with the co-operation of many airlines and NASA. The EURADOS Aircraft Crew in-flight data base was used for comparison with the predictions of various computer codes. A brief outline of some recent studies of exposure to radiation in Earth orbit will conclude this contribution.     

太阳日辐照量对太阳能热水系统热性能检测影响研究

针对太阳能热水系统热性能评价规范中对太阳辐照量要求差异较大,影响实际操作的问题,开展太阳辐照量对太阳能热水系统热性能测试的影响规律研究.该文进行86d太阳日辐照量监测和27 d对不同日辐照量下平板太阳能热水系统热性能的短期测试研究.结果显示:南京市满足测试规范要求的日辐照量天气较少,在5～10月约占总天数的28％;随着日辐照量的升高,水箱的温升增加,当日辐照量较大时,贮水箱温升与日辐照量的线性关系不明显;平板太阳能热水系统热性能评定指标系统温升性能At17与太阳日辐照量无关,由太阳能热水系统本身性能决定.对太阳能热水系统热性能检测的日辐照量要求可适当放宽,其标准需开展系统研究;太阳能热水器热水系统的日平均热效率,可作为评定指标之一.     

Characterisation of spectrophotometers used for spectral solar ultraviolet radiation measurements

Spectrophotometers used for spectral measurements of the solar ultraviolet radiation need to be well characterised to provide accurate and reliable data. Since the characterisation and calibration are usually performed in the laboratory under conditions very different from those encountered during solar measurements, it is essential to address all issues concerned with the representativity of the laboratory characterisation with respect to the solar measurements. These include among others the instrument stability, the instrument linearity, the instrument responsivity, the wavelength accuracy, the spectral resolution, stray light rejection and the instrument dependence on ambient temperature fluctuations. These instrument parameters need to be determined often enough so that the instrument changes only marginally in the period between successive characterisations and therefore provides reliable data for the intervening period.     

Anamorphic concentration of solar radiation beyond the one-dimensional thermodynamic limit

We propose and demonstrate a new scheme for anamorphic concentration of a big (40 cm x 40 cm) diffuse light source to achieve an extremely high concentration in one lateral direction at the expense of that in the other direction, to preserve the total (two-dimensional) optical brightness. Such anamorphic concentration is achieved by a combination of two conventional two-dimensional concentrators and a properly designed retroreflector array. Our experiments in search of a diffuse white-light source with properties comparable with those of solar radiation have yielded 28-fold improvement of the one-dimensional concentration ratio compared with those of conventional concentrators and 14-fold improvement compared with the one-dimensional thermodynamic limit.     

Film-type thermoelectric and the rmomagnetic thermal radiation sensors and their output parameters

Voltage-power sensitivity and time constant of a star-type film thermoelectric sensor and time constant of a film thermomagnetic sensor are calculated.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 44, No. 4, pp. 573–580, April, 1983.