[en] This invention relates to an improved wide-range radiation gage having a controlled-gain photodetector for determining a material property. Hereinafter, the invention is described with reference to accurately measuring a wide range of steel plate thicknesses, or steel strip thicknesses, in a hot steel rolling mill which normally produces a steel product under variable operating conditions. However, it will become apparent that the invention is equally applicable to gaging other materials, and other properties such as weight per unit area or density, and to other industrial installations as well as to a variety of laboratory apparatus

[en] Here, in this review article we discuss new updates on PID techniques, other than the Cherenkov method. In particular, we discuss recent efforts to develop high resolution timing, placing an emphasis on small scale test results.

[en] Some theoretical considerations and practical results regarding the utilization of the ROL 50 photovoltaic cell in a leveling control system and glass quality control equipment are presented. (authors)

[en] Two measurement techniques are investigated to characterize photodetector linearity. A model for the two-tone and three-tone photodetector systems is developed to thoroughly investigate the influences of setup components on the measurement results. We demonstrate that small bias shifts from the quadrature point of the modulator will induce deviation into measurement results of the two-tone system, and the simulation results correspond well to experimental and calculation results. (authors)

[en] The importance of laser radiation sources in photodetector calibration processes is considered and shown. As an example of that, a recently made work comparing the spectral radiant flux measurement uncertainty of several absolute radiometers is described

[en] Highlights: • Morphology evolution of the MoS₂ film was investigated, and the grain boundaries were clearly illustrated. • Continuous MoS₂ film (2~3 mm) with high quality single crystalline grains (20~100 μm) was achieved. • Polymer electrolyte (PEO: LiClO₄ =8:1) was introduced to form the side-gated FET. • The highly transparent flexible photodetector demonstrated high responsivity (33.3A/W) and good stability. In this paper, we demonstrate a large-area flexible photodetector based on vertically stacked atomically thin MoS₂/graphene film. The MoS₂ film is grown by CVD method. We have realized the growth of several square millimeter continuous monolayer MoS₂ film via precisely control the atmosphere and temperature in the tube furnace. In experiment, the MoS₂ and graphene film was transferred on PET substrate successively. Polymer electrolyte composed of PEO and LiClO₄ was introduced to fabricate the side-gated flexible photodetector. The devices exhibit high performance at low operation voltage. External responsivity is about 3.5 A/W at V_gs = −1 V, V_ds = 1 V with incident power of 60 μW (520 nm). Noteworthy is that the transmittance of the heterostructure at 520 nm is only about 10.5%, the internal responsivity even reaches to about 33.3 A/W, which is higher than most of the flexible photodetectors based on nanomaterials. Besides, the devices display high stability during transient on/off test. We believe the MoS₂/graphene photodetector would be a promising candidate in flexible electronic system. Besides, such hybrid film design is also portable and meaningful for future photodetector investigation.

No abstract available

[en] Four types of photon counters are discussed in terms of information, fidelity, and physical reversibility: conventional photon counter, quantum counter, and their quantum nondemolition (QND) versions. It is shown that when a photon field to be measured is in an arbitrary superposition of vacuum and one-photon states, the quantum counter is the most reversible, the QND version of conventional photon counter provides the most information, and the QND version of the quantum counter causes the smallest state change. Our results suggest that the physical reversibility of a counter tends to decrease the amount of information obtained by the counter.

[en] The aim of this paper is a critical investigation of some correction factors in the quantum-efficiency calibration of photodetectors, in the photon-counting regime, by means of correlated photons generated through a parametric down-conversion process inside a non-linear crystal. An analysis is given of the main correction factors found in a real experimental situation, with different techniques for performing coincidence counts. (authors)

[en] Currently, many radiation spectrometers are offered by different manufactures depending on the type of detector. It is known that stationary spectrometers have such parameters as high efficiency, low error rate, low noise factor. However, there are some problems with the use of stationary devices for the study of radiation control or expeditionary work. These problems are associated with the requirements of the devices for high operating voltage, clean laboratory conditions, temperatures of liquid nitrogen and special geometric preparation of samples for their work. Because of these problems, the use and demand of mobile radiation monitoring devices is growing. A new mobile radiation spectrometer was proposed in the work. The main part of the proposed spectrometer is a semiconductor photodetector. These photodetectors were developed by our scientific and technical group and have a wide potential for application in such fields as high-energy physics, medicine, spectrometry and radiation safety.