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Silicon detector

Chunsheng Wu, Liping Du, Yulan Tian, Xi Zhang, Ping Wang
A light-addressable potentiometric sensor (LAPS), a silicon-based surface potential detector, is combined with bioengineered olfactory sensory neurons (OSN) for odorant detection. A LAPS chip is used as a transducer to monitor cell membrane potential changes. In addition, a focused movable laser with a diameter comparable to cell sizes is employed to select the desirable single cell for measurement under a microscope. Bioengineered OSNs are coupled to the LAPS surface and employed as sensing elements, which are prepared by the expression of an olfactory receptor of C...
2017: Methods in Molecular Biology
Fei Xia, David Sinefeld, Bo Li, Chris Xu
We introduce a simple wavefront sensing scheme for aberration measurement of pulsed laser beams in near-infrared wavelengths (<2200  nm), where detectors are not always available or are very expensive. The method is based on two-photon absorption in a silicon detector array for longer wavelengths detection. We demonstrate the simplicity of such implementations with a commercially available Shack-Hartmann wavefront sensor and discuss the detection sensitivity of this method.
March 15, 2017: Optics Letters
Jacob T Held, Samuel Duncan, K Andre Mkhoyan
Quantitative ADF-STEM imaging paired with image simulations has proven to be a powerful technique for determining the three dimensional location of substitutionally doped atoms in thin films. Expansion of this technique to lightly-doped nanocrystals requires an understanding of the influence of specimen mistilt on dopant visibility due to the difficulty of accurate orientation determination in such systems as well as crystal movement under the beam. In this study, the effects of specimen mistilt on ADF-STEM imaging are evaluated using germanium-doped silicon nanocrystals as model systems...
March 7, 2017: Ultramicroscopy
Michael Mengason, Nicholas Ritchie
The evolution of the energy dispersive spectrometer (EDS) from the lithium-drifted silicon detector [Si(Li)] to the silicon drift detector (SDD) has created new opportunities in the field of electron probe X-ray microanalysis. The SDD permits operation at significantly higher count rates than the Si(Li) and also provides a more stable energy scale. X-ray spectra captured by EDS can now be analyzed qualitatively or quantitatively under the same beam conditions as used for wavelength dispersive spectrometry (WDS)...
March 10, 2017: Microscopy and Microanalysis
Mehran Yarahmadi, Sonja Wegener, Otto A Sauer
PURPOSE: To investigate the energy dependence/spectral sensitivity of silicon diodes designed for small-field dosimetry and obtain response factors (RFs) for arbitrary photon spectra using Monte Carlo (MC) simulations. METHODS: The EGSnrc user-code DOSRZnrc was used to calculate the dose deposition in water and in the active volume of a stereotactic diode field detector (SFD). Then the RFs of the SFD were calculated for several circular field sizes and energies at 5 cm depth in water...
March 8, 2017: Medical Physics
Hyeok-Jun Choe, Yong Choi, Wei Hu, Jianhua Yan, Jin Ho Jung
There has been great interest in developing a time-of-flight (TOF) PET to improve the signal-to-noise ratio of PET image relative to that of non-TOF PET. Silicon photomultiplier (SiPM) arrays have attracted attention for use as a fast TOF PET photosensor. Since numerous SiPM arrays are needed to construct a modern human PET, a multiplexing method providing both good timing performance and high channel reduction capability is required to develop a SiPM-based TOF PET. The purpose of this study was to develop a capacitive multiplexing circuit for the SiPM-based TOF PET...
April 7, 2017: Physics in Medicine and Biology
M C Ovejero, A Pérez Vega-Leal, M I Gallardo, J M Espino, A Selva, M A Cortés-Giraldo, R Arráns
The aim of this work is to present a new data acquisition, control, and analysis software system written in LabVIEW. This system has been designed to obtain the dosimetry of a silicon strip detector in polyethylene. It allows the full automation of the experiments and data analysis required for the dosimetric characterization of silicon detectors. It becomes a useful tool that can be applied in the daily routine check of a beam accelerator.
February 2017: Review of Scientific Instruments
Jong-Bum You, Hyeokbin Kwon, Jonghoon Kim, Hyo-Hoon Park, Kyoungsik Yu
We demonstrate silicon ridge waveguide photo-detectors capable of sub-bandgap light absorption and avalanche multiplication. The proposed waveguide photo-detectors contain highly doped PN junction, where a strong electric field can generate the photon-assisted tunneling current for sub-bandgap light incidence and amplify the generated photo-current by the avalanche multiplication effect. The voltage-dependent sub-bandgap absorption coefficient and multiplication gain are experimentally evaluated for various doping configurations to find optimal photo-response with low dark currents...
February 20, 2017: Optics Express
Javad Ghasemi, Manish Bhattarai, Glauco R C Fiorante, Payman Zarkesh-Ha, Sanjay Krishna, Majeed M Hayat
A hardware implementation of a real-time compressed-domain image acquisition system is demonstrated. The system performs front-end computational imaging, whereby the inner product between an image and an arbitrarily-specified mask is implemented in silicon. The acquisition system is based on an intelligent readout integrated circuit (iROIC) that is capable of providing independent bias voltages to individual detectors, which enables implementation of spatial multiplication with any prescribed mask through a bias-controlled response-modulation mechanism...
February 20, 2017: Optics Express
Haijie Zuo, Duk-Yong Choi, Xin Gai, Barry Luther-Davies, Baoping Zhang
We present a novel CMOS-compatible fabrication technique for convex micro-nano lens arrays (MNLAs) with high packing density on the wafer scale. By means of conformal chemical vapor deposition (CVD) of hydrogenated amorphous silicon (a-Si:H) following patterning of silicon pillars via electron beam lithography (EBL) and plasma etching, large areas of a close packed silicon lens array with the diameter from a few micrometers down to a few hundred nanometers was fabricated. The resulting structure shows excellent surface roughness and high uniformity...
February 20, 2017: Optics Express
K Khrustalev, V Yu Popov, Yu S Popov
We present a new second generation SiPIN based electron-photon coincidence detector system developed by Lares Ltd. for use in the Noble Gas measurement systems of the International Monitoring System and the On-site Inspection verification regimes of the Comprehensive Nuclear-Test Ban Treaty (CTBT). The SiPIN provide superior energy resolution for electrons. Our work describes the improvements made in the second generation detector cells and the potential use of such detector systems for other applications such as In-Situ Kr-85 measurements for non-proliferation purposes...
February 14, 2017: Applied Radiation and Isotopes
Matteo Morrocchi, Giovanni Ambrosi, Maria Giuseppina Bisogni, Filippo Bosi, Marco Boretto, Piergiorgio Cerello, Maria Ionica, Ben Liu, Francesco Pennazio, Maria Antonietta Piliero, Giovanni Pirrone, Vasile Postolache, Richard Wheadon, Alberto Del Guerra
BACKGROUND: Monolithic scintillators read out by arrays of photodetectors represent a promising solution to obtain high spatial resolution and the depth of interaction (DOI) of the annihilation photon. We have recently investigated a detector geometry composed of a monolithic scintillator readout on two sides by silicon photomultiplier (SiPM) arrays, and we have proposed two parameters for the DOI determination: the difference in the number of triggered SiPMs on the two sides of the detector and the difference in the maximum collected signal on a single SiPM on each side...
December 2017: EJNMMI Physics
Matthew J Byrd, Erman Timurdogan, Zhan Su, Christopher V Poulton, Nicholas M Fahrenkopf, Gerald Leake, Douglas D Coolbaugh, Michael R Watts
We propose a mode-evolution-based coupler for high saturation power germanium-on-silicon photodetectors. This coupler uniformly illuminates the intrinsic germanium region of the detector, decreasing saturation effects, such as carrier screening, observed at high input powers. We demonstrate 70% more photocurrent generation (9.1-15.5 mA) and more than 40 times higher opto-electrical bandwidth (0.7-31 GHz) than conventional butt-coupled detectors under high-power illumination. The high-power and high-speed performance of the device, combined with the compactness of the coupling method, will enable new applications for integrated silicon photonics systems...
February 15, 2017: Optics Letters
Valerio Tabacchini, Suleman Surti, Giacomo Borghi, Joel S Karp, Dennis R Schaart
We have recently built and characterized the performance of a monolithic scintillator detector based on a 32 mm  ×  32 mm  ×  22 mm LYSO:Ce crystal read out by digital silicon photomultiplier (dSiPM) arrays coupled to the crystal front and back surfaces in a dual-sided readout (DSR) configuration. The detector spatial resolution appeared to be markedly better than that of a detector consisting of the same crystal with conventional back-sided readout (BSR). Here, we aim to evaluate the influence of this difference in the detector spatial response on the quality of reconstructed images, so as to quantify the potential benefit of the DSR approach for high-resolution, whole-body time-of-flight (TOF) positron emission tomography (PET) applications...
February 13, 2017: Physics in Medicine and Biology
Alan T Marshall
It is shown that accurate x-ray microanalysis of frozen-hydrated and dry organic compounds, such as model biological samples, is possible with a silicon drift detector in combination with XPP (exponential model of Pouchou and Pichoir matrix correction) software using 'remote standards'. This type of analysis is also referred to as 'standardless analysis'. Analyses from selected areas or elemental images (maps) were identical. Improvements in x-ray microanalytical hardware and software, together with developments in cryotechniques, have made the quantitative analysis of cryoplaned frozen-hydrated biological samples in the scanning electron microscope a much simpler procedure...
February 9, 2017: Journal of Microscopy
P Sibson, C Erven, M Godfrey, S Miki, T Yamashita, M Fujiwara, M Sasaki, H Terai, M G Tanner, C M Natarajan, R H Hadfield, J L O'Brien, M G Thompson
Improvement in secure transmission of information is an urgent need for governments, corporations and individuals. Quantum key distribution (QKD) promises security based on the laws of physics and has rapidly grown from proof-of-concept to robust demonstrations and deployment of commercial systems. Despite these advances, QKD has not been widely adopted, and large-scale deployment will likely require chip-based devices for improved performance, miniaturization and enhanced functionality. Here we report low error rate, GHz clocked QKD operation of an indium phosphide transmitter chip and a silicon oxynitride receiver chip-monolithically integrated devices using components and manufacturing processes from the telecommunications industry...
February 9, 2017: Nature Communications
Li Tao, Henry M Daghighian, Craig S Levin
We compare the performance of two detector materials, cadmium telluride (CdTe) and bismuth silicon oxide (BSO), for optical property modulation-based radiation detection method for positron emission tomography (PET), which is a potential new direction to dramatically improve the annihilation photon pair coincidence time resolution. We have shown that the induced current flow in the detector crystal resulting from ionizing radiation determines the strength of optical modulation signal. A larger resistivity is favorable for reducing the dark current (noise) in the detector crystal, and thus the higher resistivity BSO crystal has a lower (50% lower on average) noise level than CdTe...
January 2017: Journal of Medical Imaging
Valerio Adinolfi, Edward H Sargent
The detection of infrared radiation enables night vision, health monitoring, optical communications and three-dimensional object recognition. Silicon is widely used in modern electronics, but its electronic bandgap prevents the detection of light at wavelengths longer than about 1,100 nanometres. It is therefore of interest to extend the performance of silicon photodetectors into the infrared spectrum, beyond the bandgap of silicon. Here we demonstrate a photovoltage field-effect transistor that uses silicon for charge transport, but is also sensitive to infrared light owing to the use of a quantum dot light absorber...
February 8, 2017: Nature
Saransh Singh, Marc De Graef
The dictionary-based approach to the indexing of diffraction patterns is applied to electron channeling patterns (ECPs). The main ingredients of the dictionary method are introduced, including the generalized forward projector (GFP), the relevant detector model, and a scheme to uniformly sample orientation space using the "cubochoric" representation. The GFP is used to compute an ECP "master" pattern. Derivative free optimization algorithms, including the Nelder-Mead simplex and the bound optimization by quadratic approximation are used to determine the correct detector parameters and to refine the orientation obtained from the dictionary approach...
February 6, 2017: Microscopy and Microanalysis
Lingxia Huang, Yibin Zhou, Liuwei Meng, Di Wu, Yong He
This study investigated the potential of using hyperspectral imaging technique in tandem with chemometrics for rapid and invasive predicting total anthocyanin content and antioxidant activity of mulberry fruit. Two calibration methods of partial least square regression and least-squares support vector machines and three wavelength selection algorithms of successive projections algorithm, uninformation variable elimination, and competitive adaptive reweighted sampling were applied. The best prediction models for the analysis of total anthocyanin content and antioxidant activity had Rval(2) of 0...
June 1, 2017: Food Chemistry
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