Recent research on photodetectors has been mainly focused on nanostructured materials that form the building blocks of device fabrication. The selection of a suitable material with well-defined properties forms the key issue for the fabrication of photodetectors that cover different ranges of the electromagnetic spectrum. In this review, the latest progress in light detection using nanobelts, nanoribbons, nanosheets and the emerging two-dimensional (2D) materials is reviewed. Particular emphasis is placed on the detection of light by the hybrid structures of the mentioned nanostructured materials in order to enhance the efficiency of the light–matter interaction. The booming research area of black phosphorus based photo-detection is also reviewed. This review provides an overview of basic concepts and new directions towards photodetectors, and highlights potential for the future development of high performance broadband photodetectors.

Present perspectives of broadband photodetectors based on nanobelts, nanoribbons, nanosheets and the emerging 2D materials

A deep underwater Cherenkov telescope has been operating since 1993 in stages of growing size at 1.1 km depth in Lake Baikal. The key component of the telescope is the Optical Module (OM) which houses the highly sensitive phototube QUASAR-370. We describe design and parameters of the QUASAR-370, the layout of the optical module, the front-end electronics and the calibration procedures, and present selected results from the five-year operation underwater. Also, future developments with respect to a telescope consisting from several thousand OMs are discussed.

http://cds.cern.ch/record/361118/files/9903347.pdf

The optical module of the Baikal deep underwater neutrino telescope

Applications of conversion electron Mössbauer spectrometry (CEMS)

Magnetic hyperfine fields near the Fe / Cr (100, 110) interface studied by CEMS

Conversion electron Mossbauer spectroscopy (CEMS) has been used as a standard technique since details for the construction of appropriate electron gas counters were reported. In this paper after a short description of physical bases of CEMS, the methodological aspects of this technique are outlined.

Cems methodology

A low-noise scintillation counter has been developed for the detection of low-intensity, low-energy (several keV) electrons in high vacuum. Performance comparisons with a channeltron for 57 Fe depth-selective conversion electron Mossbauer spectroscopy (DCEMS) show a substantial improvement in counting time in favour of the scintillation detector.

Improvements in 57Fe depth-selective conversion electron Mössbauer spectroscopy by applying a low-noise scintillation electron detector

A large area electro-optical pre-amplifier photomultiplier combination for the DUMAND array is proposed with excellent single and multi-electron resolution compared with conventional photomultipliers. Photo-electrons from a hemispherical photocathode are accelerated to and collected on a fast phosphor screen, behind which a conventional photomultiplier is placed. The combination works as a photomultiplier with a very high gain (~ 50) first dynode. The design will be described and data will be given on collection efficiency, gain, single electron resolution, background, transit time and afterpulses. These properties will be discussed in view of the requirements for the DUMAND array and other applications.

An Electro-Optical Pre-Amplifier Photomultiplier Combination with Integrated Power Supply Offering Excellent Single Electron Resolution for DUMAND

Applications of DCEMS or ICEMS for UHV studies of surfaces and interfaces are often severely limited by long recording times. To clarify the practical means to shorten this time, we introduce the “statistical utility rate” α characterizing the statistical quality of a given measurement. By improving detection efficiency and reducing background contribution simultaneously, we have developed an extremely low-noise scintillation detector (Hamamatsu R1635-02 or R2557 photomultiplier with P-47 thin-layer phosphor). Performance comparison with a channeltron by57Fe-DCEMS measurements on an 90% enriched57Fe foil with 7.2 keV electrons reveals a measuring time gain over an order of magnitude in favour of the scintillation e-detector. Improvements achievable for samples with normal isotope abundance are higher than for enriched ones.

G. Van Aller

Papers

Improvements in 57Fe depth-selective conversion electron Mössbauer spectroscopy by applying a low-noise scintillation electron detector

An Electro-Optical Pre-Amplifier Photomultiplier Combination with Integrated Power Supply Offering Excellent Single Electron Resolution for DUMAND

Performance-improvement in57Fe-DCEMS by an optimized scintillation counter

The influence of an elastic stress on the electrical resistance of copper after plastic deformation