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Silicon detector

Haolan Zhao, Stéphane Clemmen, Ali Raza, Roel Baets
We report, to the best of our knowledge, the first demonstration of stimulated Raman spectroscopy enhanced by a nanophotonic integrated circuit. The Raman response of low-concentration dimethyl sulfoxide is evanescently probed via centimeter-long wire waveguides. A signal enhancement of close to five orders of magnitude, as compared to the case of on-chip spontaneous Raman scattering, is demonstrated. This significant enhancement factor allows for the use of continuous-wave lasers with milliwatt-level power and uncooled detectors and, therefore, sets the basis of future all-on-a-chip Raman spectrometers suitable for both gas and liquid detection...
March 15, 2018: Optics Letters
Rai Kou, Taiki Hatakeyama, Jason Horng, Ji-Hun Kang, Yuan Wang, Xiang Zhang, Feng Wang
Mid-infrared light provides numerous unexpected opportunities in scientific discoveries because this wavelength region covers the fingerprints of various molecular vibrational resonances. However, the light generation efficiency and bandwidth have been a long-standing bottleneck which has limited the development so far. Moreover, the light source that can be integrated with other components such as wavelength filters, detectors, and electronics, will be the key factor toward the future practical applications...
March 15, 2018: Optics Letters
Xuhui Geng, Meng Shi, Haijing Ning, Chunbo Feng, Yafeng Guan
A compact and low-cost laser induced fluorescence (LIF) detector based on confocal structure for capillary flow systems was developed and applied for analysis of Her2 protein on single Hela cells. A low-power and low-cost 450 nm laser diode (LD) instead of a high quality laser was used as excitation light source. A compact optical design together with shortened optical path length improved the optical efficiency and detection sensitivity. A superior silicon based photodetector assembly was used for fluorescence detection instead of a photomultiplier (PMT)...
May 15, 2018: Talanta
Suelen F Barros, Vito R Vanin, Alexandre A Malafronte, Nora L Maidana, Marcos N Martins
Dead-time effects in X-ray spectra taken with a digital pulse processor and a silicon drift detector were investigated when the number of events at the low-energy end of the spectrum was more than half of the total, at counting rates up to 56 kHz. It was found that dead-time losses in the spectra are energy dependent and an analytical correction for this effect, which takes into account pulse pile-up, is proposed. This and the usual models have been applied to experimental measurements, evaluating the dead-time fraction either from the calculations or using the value given by the detector acquisition system...
March 1, 2018: Journal of Synchrotron Radiation
G Biasi, M Petasecca, S Guatelli, N Hardcastle, M Carolan, V Perevertaylo, T Kron, A B Rosenfeld
PURPOSE: Flattening filter free (FFF) beams are increasingly being considered for stereotactic radiotherapy (SRT). For the first time, the performance of a monolithic silicon array detector under 6 and 10 MV FFF beams was evaluated. The dosimeter, named "Octa" and designed by the Centre for Medical Radiation Physics (CMRP), was tested also under flattened beams for comparison. METHODS: Output factors (OFs), percentage depth-dose (PDD), dose profiles (DPs) and dose per pulse (DPP) dependence were investigated...
January 2018: Physica Medica: PM
Dong Yuan, Wang Di, Wei Zhi, Fu Tai Ran
In this paper, an experimental study of silicon-based avalanche photodiode (Si-APD) with millisecond pulse laser irradiation was carried out, and the C-V curve of Si-APD was obtained by using a semiconductor analyzer. Based on the single-side abrupt junction character of n+p, combined with the corresponding theoretical derivation, the doping concentration varying with the axial depth of damaged Si-APD was obtained by inverse computation. The lattice dislocation and junction reduction were the fundamental causes of the reduced doping concentration...
February 10, 2018: Applied Optics
Chanyoung Yim, Niall McEvoy, Sarah Riazimehr, Daniel Schneider, Farzan Gity, Scott Monaghan, Paul K Hurley, Max C Lemme, Georg S Duesberg
Platinum diselenide (PtSe2 ) is a group-10 transition metal dichalcogenide (TMD) that has unique electronic properties, in particular a semimetal-to-metal transition when going from bulk to monolayer form. We report on vertical hybrid Schottky barrier diodes (SBDs) of two-dimensional (2D) PtSe2 thin films on crystalline n-type silicon. The diodes have been fabricated by transferring large-scale layered PtSe2 films, synthesized by thermally assisted conversion at back-end-of-the-line CMOS compatible temperatures of pre-deposited Pt films...
February 20, 2018: Nano Letters
Sangeetha Jayakumar, T Saravanan, John Philip
Nanocomposites containing α-Bi2O3, β-Bi2O3 and Bi nanoparticles as nanofillers in vulcanized silicone resin as a matrix are prepared and their diagnostic X-ray attenuation property is studied. The nanocomposites are prepared using a simple solution casting technique, with nanofiller concentration varying from 2-50 wt%. Thermogravimetric analysis and differential scanning calorimetry are performed to study the thermal stability of the nanocomposites. The attenuation property is studied by exposing the nanocomposites containing α-Bi2O3, β-Bi2O3 and Bi nanoparticles to X-rays of energy 30-60 keV...
June 1, 2018: Journal of Nanoscience and Nanotechnology
Zhonghua Kuang, Qian Yang, Xiaohui Wang, Xin Fu, Ning Ren, Ziru Sang, San Wu, Yunfei Zheng, Xianming Zhang, Zhanli Hu, Junwei Du, Dong Liang, Xin Liu, Hairong Zheng, Yongfeng Yang
Detectors with depth-encoding capability and good timing resolution are required to develop high-performance whole-body or total-body PET scanners. In this work, depth-encoding PET detectors that use light sharing between two discrete crystals and single-ended readout with silicon photomultipliers (SiPMs) were manufactured and evaluated. The detectors consisted of two unpolished 3 × 3 × 20 mm 3 LYSO crystals with different coupling materials between them and were read out by Hamamatsu 3 × 3 mm 2 SiPMs with one-to-one coupling...
February 13, 2018: Physics in Medicine and Biology
Maurizio Zani, Vittorio Sala, Gabriele Irde, Silvia Maria Pietralunga, Cristian Manzoni, Giulio Cerullo, Guglielmo Lanzani, Alberto Tagliaferri
The excitation dynamics of defects in insulators plays a central role in a variety of fields from Electronics and Photonics to Quantum computing. We report here a time-resolved measurement of electron dynamics in 100 nm film of aluminum oxide on silicon by Ultrafast Scanning Electron Microscopy (USEM). In our pump-probe setup, an UV femtosecond laser excitation pulse and a delayed picosecond electron probe pulse are spatially overlapped on the sample, triggering Secondary Electrons (SE) emission to the detector...
January 31, 2018: Ultramicroscopy
Modeste Tchakoua Tchouaso, William H Miller
Accurate measurement of beta skin dose remains a challenge. This dose is defined as the dose to the basil layer at 7 mg/cm2 (approximately 70 µm) below the surface of the skin and averaged over an area of 1 cm2. This dose is dependent upon the energy of the beta contamination on the surface of the skin, the area of contamination and the attenuation of this radiation through the 7 mg/cm2 epidermal layer. Ideally, knowing the energy spectra of betas at this level below the surface of the skin would allow accurate prediction of dose...
January 25, 2018: Applied Radiation and Isotopes
Lin Tang, Jie Yu, Jianbin Zhou, Fang Fang, Wenjie Wan, Jianfeng Yao, Songke Yu, Xianli Liao
To get a precise X-ray energy spectrum from the latest high-performance silicon drift detector (fast SDD), a switch reset preamplifier circuit, which has a high signal to noise ratio and small ballistic loss, is used to amplify the weak signal transmitted by the detector. Aiming at the technical problem of fast SDD, which works at high-count rate conditions, we adopt a slow triangle shaping method and use switch reset type preamplifier, and a new method is put forward to remove the false peaks to obtain a precise X-ray spectrum, in essence, to eliminate the distorted pulses transmitted by the detector...
February 2, 2018: Applied Radiation and Isotopes
Suleman Surti, Joel S Karp
The advent of silicon photomultipliers (SiPMs) has introduced the possibility of increased detector performance in commercial whole-body PET scanners. The primary advantage of these photodetectors is the ability to couple a single SiPM channel directly to a single pixel of PET scintillator that is typically 4 mm wide (one-to-one coupled detector design). We performed simulation studies to evaluate the impact of three different event positioning algorithms in such detectors: i) a weighted energy centroid positioning (Anger logic), ii) identifying the crystal with maximum energy deposition (1<sup>st</sup> max crystal), and iii) identifying the crystal with second highest energy deposition (2<sup>nd</sup> max crystal)...
February 7, 2018: Physics in Medicine and Biology
Till Mohr, Andreas Herdt, Wolfgang Elsässer
A 2D tomographic terahertz imaging set-up using a single pixel imaging approach is realized, where a liquid helium cooled bolometer is utilized as a bucket detector and a mercury-arc lamp serves as a broadband terahertz source. The different patterns of the terahertz radiation, which are necessary for the single pixel imaging approach, are realized by spatially addressed photodoping of a high resistivity float zone silicon window, employing a near-infrared laser diode, which is spatially modulated by a digital micromirror device...
February 5, 2018: Optics Express
Ajanta Barh, Peter Tidemand-Lichtenberg, Christian Pedersen
Low noise detection with state-of-the-art mid-infrared (MIR) detectors (e.g., PbS, PbSe, InSb, HgCdTe) is a primary challenge owing to the intrinsic thermal background radiation of the low bandgap detector material itself. However, researchers have employed frequency upconversion based detectors (UCD), operable at room temperature, as a promising alternative to traditional direct detection schemes. UCD allows for the use of a low noise silicon-CCD/camera to improve the SNR. Using UCD, the noise contributions from the nonlinear material itself should be evaluated in order to estimate the limits of the noise-equivalent power of an UCD system...
February 5, 2018: Optics Express
Shuomin Zhong, Taijun Liu, Jifu Huang, Yungui Ma
We theoretically demonstrate a giant power enhancement effect for a line current source in a ε-near-zero (ENZ) two-dimensional (2D) shell with proper physical dimensions. Compared with the traditional high-ε dielectric approach, the ENZ scheme has the prominent advantage that the radiation performance is less sensitive to the outer radius of the shell, which is critically important for real applications where micro-nano fabrications are often involved. The enhancing performance is independent on the position of the source inside the ENZ shell and could be substantially strengthened by incorporating more sources, while the quasi-omnidirectional radiation pattern could be managed to have negligible variance, as evidenced by a particular example with an inner radius of the shell equal to 0...
February 5, 2018: Optics Express
F Kenneth Hopkins, Nicholas G Usechak, Hyunjun Kim, Xiaojin Wang, Hiren Trada, Kevin M Walsh
An innovative approach is proposed and demonstrated for measuring the attenuation of light in optical fibers. The technique utilizes a silicon device containing a v-groove that positions the fiber and detector array along the v-groove. The detectors within the v-groove are designed to partially surround the fiber in order to maximize the coupling of scattered light from the fiber into each detector.
January 20, 2018: Applied Optics
Yaran Li, Qing Xie, Zhiqiang Chen, Qiuqi Xin, Xin Wang, Baozhong Mu, Zhanshan Wang, Shenye Liu, Yongkun Ding
Direct intensity calibration of X-ray grazing-incidence microscopes is urgently needed in quantitative studies of X-ray emission from laser plasma sources in inertial confinement fusion. The existing calibration methods for single reflecting mirrors, crystals, gratings, filters, and X-ray detectors are not applicable for such X-ray microscopes due to the specific optical structure and the restrictions of object-image relation. This article presents a reliable and efficient method that can be performed using a divergent X-ray source and an energy dispersive Si-PIN (silicon positive-intrinsic-negative) detector in an ordinary X-ray laboratory...
January 2018: Review of Scientific Instruments
Gitanjali Kolhatkar, Abderraouf Boucherif, Abderrahim Boucherif, Arthur Dupuy, Luc G Frechette, Richard Ares, Andreas Ruediger
We demonstrate the thermal stability and thermal insulation of graphene-mesoporous silicon nanocomposites. By comparing the morphology of graphene-mesoporous silicon nanocomposite carbonized at 650°C as-formed to that after annealing, we show that this nanocomposite remains stable at temperatures as high as 1050°C due to the presence of a few monolayers of graphene coating on the pore walls. This does not only make this material compatible with most thermal processes but also suggests applications in harsh high temperature environments...
February 1, 2018: Nanotechnology
C De Angelis, A Ampollini, E Basile, E Cisbani, S Della Monaca, F Ghio, R M Montereali, L Picardi, M Piccinini, C Placido, C Ronsivalle, A Soriani, L Strigari, E Trinca, M Vadrucci
The first proton linear accelerator for tumor therapy based on an actively scanned beam up to the energy of 150 MeV, is under development and construction by ENEA-Frascati, ISS and IFO, under the Italian TOP-IMPLART project. Protons up to the energy of 7 MeV are generated by a customized commercial injector operating at 425 MHz; currently three accelerating modules allow proton delivery with energy up to 27 MeV. Beam homogeneity and reproducibility were studied using a 2D ionizing chamber, EBT3 films, a silicon diode, MOSFETs, LiF crystals and alanine dosimetry systems...
January 29, 2018: Radiation Protection Dosimetry
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