WorldWideScience

Sample records for inexpensive silicon photodiode

  1. A radiation detector fabricated from silicon photodiode.

    Science.gov (United States)

    Yamamoto, H; Hatakeyama, S; Norimura, T; Tsuchiya, T

    1984-12-01

    A silicon photodiode is converted to a low energy charged particle radiation detector. The window thickness of the fabricated detector is evaluated to be 50 micrograms/cm2. The area of the depletion region is 13.2 mm2 and the depth of it is estimated to be about 100 microns. The energy resolution (FWHM) is 14.5 ke V for alpha-particles from 241Am and 2.5 ke V for conversion electrons from 109Cd, respectively.

  2. Low Cost silicon photodiodes for alpha spectrometry

    International Nuclear Information System (INIS)

    Khoury, H.; Lopes, A.; Hazin, C.; Lira, C.B.; Silva, E. da

    1998-01-01

    This study was carried out to evaluate the suitability of using commercially available photodiodes for alpha spectrometry, since the principle on which both operate are similar. Photodiodes are low priced compared to the commonly used semiconductor detectors making them potentially useful for research and teaching purposes. Very thin calibrated alpha sources of 2 41 A m, 2 44 C m and 2 35 U , produced at the Metrology Laboratory of IRD/CNEN, were used to test the performance of three photodiodes. The results showed that the responses of the photodiodes were linear with the alpha particle energy and that the energy resolution varied between 0,79% and 0,45%, with an efficiency of 8%. The resolution and efficiency presented by the photodiodes tested are similar to those obtained with other semiconductor detectors, evidencing that they can be used successfully as alpha detectors

  3. Novel vertical silicon photodiodes based on salicided polysilicon trenched contacts

    International Nuclear Information System (INIS)

    Kaminski, Yelena; Shauly, Eitan; Paz, Yaron

    2015-01-01

    The classical concept of silicon photodiodes comprises of a planar design characterized by heavily doped emitters. Such geometry has low collection efficiency of the photons absorbed close to the surface. An alternative, promising, approach is to use a vertical design. Nevertheless, realization of such design is technologically challenged, hence hardly explored. Herein, a novel type of silicon photodiodes, based on salicided polysilicon trenched contacts, is presented. These contacts can be prepared up to 10 μm in depth, without showing any leakage current associated with the increase in the contact area. Consequently, the trenched photodiodes revealed better performance than no-trench photodiodes. A simple two dimensional model was developed, allowing to estimate the conditions under which a vertical design has the potential to have better performance than that of a planar design. At large, the deeper the trench is, the better is the vertical design relative to the planar (up to 10 μm for silicon). The vertical design is more advantageous for materials characterized by short diffusion lengths of the carriers. Salicided polysilicon trenched contacts open new opportunities for the design of solar cells and image sensors. For example, these contacts may passivate high contact area buried contacts, by virtue of the conformity of polysilicon interlayer, thus lowering the via resistance induced recombination enhancement effect

  4. Novel vertical silicon photodiodes based on salicided polysilicon trenched contacts

    Energy Technology Data Exchange (ETDEWEB)

    Kaminski, Yelena [Department of Chemical Engineering, Technion, Haifa (Israel); TowerJazz Ltd. Migdal Haemek (Israel); Shauly, Eitan [TowerJazz Ltd. Migdal Haemek (Israel); Paz, Yaron, E-mail: paz@tx.technion.ac.il [Department of Chemical Engineering, Technion, Haifa (Israel)

    2015-12-07

    The classical concept of silicon photodiodes comprises of a planar design characterized by heavily doped emitters. Such geometry has low collection efficiency of the photons absorbed close to the surface. An alternative, promising, approach is to use a vertical design. Nevertheless, realization of such design is technologically challenged, hence hardly explored. Herein, a novel type of silicon photodiodes, based on salicided polysilicon trenched contacts, is presented. These contacts can be prepared up to 10 μm in depth, without showing any leakage current associated with the increase in the contact area. Consequently, the trenched photodiodes revealed better performance than no-trench photodiodes. A simple two dimensional model was developed, allowing to estimate the conditions under which a vertical design has the potential to have better performance than that of a planar design. At large, the deeper the trench is, the better is the vertical design relative to the planar (up to 10 μm for silicon). The vertical design is more advantageous for materials characterized by short diffusion lengths of the carriers. Salicided polysilicon trenched contacts open new opportunities for the design of solar cells and image sensors. For example, these contacts may passivate high contact area buried contacts, by virtue of the conformity of polysilicon interlayer, thus lowering the via resistance induced recombination enhancement effect.

  5. A 75 GHz silicon metal-semiconductor-metal Schottky photodiode

    International Nuclear Information System (INIS)

    Alexandrou, S.; Wang, C.; Hsiang, T.Y.; Liu, M.Y.; Chou, S.Y.

    1993-01-01

    The ultrafast characteristics of crystalline-silicon metal-semiconductor-metal (MSM) photodiodes with 300 nm finger width and spacing were measured with a subpicosecond electro-optic sampling system. Electrical responses with full width at half maximum as short as 5.5 and 11 ps, at corresponding 3 dB bandwidths of 75 and 38 GHz, were generated by violet and red photons, respectively. The difference is attributed to the photon penetration depth which is much larger than the diode finger spacing at red, but smaller at violet. Light-intensity dependence was also examined at different wavelengths, indicating a linear relation and a higher sensitivity in the violet. These results not only demonstrated the fastest silicon photodetector reported to date, but also pinpointed the dominant speed-limiting factor of silicon MSM photodiodes. A configuration is suggested to improve the speed of these detectors at long wavelengths

  6. Fast neutron damage of silicon pin photodiodes

    International Nuclear Information System (INIS)

    Dabrowski, W.; Korbel, K.; Skoczen, A.

    1990-01-01

    A Hamamatsu Photonics photodiode S1723 was tested with respect to the fast neutron radiation. The device was irradiated with neutrons of energies in the range of 0.5 MeV to 12 MeV from a Po-Be source. The irradiation was performed in several steps starting from the relatively low fluence of 2.5 x 10 10 n x cm -2 . The following characteristics were measured: leakage current vs bias voltage, capacitance vs bias voltage and vs frequency, noise vs time constant of a quasigaussian shaper and spectral density of noise. Significant changes of the leakage current and of the noise were observed at the fluence of neutrons as low as 2.5 x 10 10 n x cm -2 . 8 figs., 3 tabs., 15 refs. (author)

  7. New silicon photodiodes for detection of the 1064nm wavelength radiation

    Science.gov (United States)

    Wegrzecki, Maciej; Piotrowski, Tadeusz; Puzewicz, Zbigniew; Bar, Jan; Czarnota, Ryszard; Dobrowolski, Rafal; Klimov, Andrii; Kulawik, Jan; Kłos, Helena; Marchewka, Michał; Nieprzecki, Marek; Panas, Andrzej; Seredyński, Bartłomiej; Sierakowski, Andrzej; Słysz, Wojciech; Synkiewicz, Beata; Szmigiel, Dariusz; Zaborowski, Michał

    2016-12-01

    In this paper a concept of a new bulk structure of p+-υ-n+ silicon photodiodes optimized for the detection of fast-changing radiation at the 1064 nm wavelength is presented. The design and technology for two types of quadrant photodiodes, the 8-segment photodiode and the 32-element linear photodiode array that were developed according to the concept are described. Electric and photoelectric parameters of the photodiodes mentioned above are presented.

  8. Highly enhanced avalanche probability using sinusoidally-gated silicon avalanche photodiode

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Shingo; Namekata, Naoto, E-mail: nnao@phys.cst.nihon-u.ac.jp; Inoue, Shuichiro [Institute of Quantum Science, Nihon University, 1-8-14 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8308 (Japan); Tsujino, Kenji [Tokyo Women' s Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666 (Japan)

    2014-01-27

    We report on visible light single photon detection using a sinusoidally-gated silicon avalanche photodiode. Detection efficiency of 70.6% was achieved at a wavelength of 520 nm when an electrically cooled silicon avalanche photodiode with a quantum efficiency of 72.4% was used, which implies that a photo-excited single charge carrier in a silicon avalanche photodiode can trigger a detectable avalanche (charge) signal with a probability of 97.6%.

  9. The Use of Self-scanned Silicon Photodiode Arrays for Astronomical Spectrophotometry

    Science.gov (United States)

    Cochran, A. L.

    1984-01-01

    The use of a Reticon self scanned silicon photodiode array for precision spectrophotometry is discussed. It is shown that internal errors are + or - 0.003 mag. Observations obtained with a photodiode array are compared with observations obtained with other types of detectors with agreement, from 3500 A to 10500 A, of 1%. The photometric properties of self scanned photodiode arrays are discussed. Potential pitfalls are given.

  10. Experimental studies on using silicon photodiode as read-out component of CsI(Tl) crystal

    International Nuclear Information System (INIS)

    He Jingtang; Chen Duanbao; Li Zuhao; Mao Yufang; Dong Xiaoli

    1996-01-01

    Experimental studies on using silicon photodiode as the read-out component of CsI(Tl) crystal are reported. The read-out properties of two different types of silicon photodiode produced by Hamamatsu were measured, including relations between energy resolution and bias, shaping time, sensitive area of photodiode and the dimension of the crystal

  11. High quantum efficiency annular backside silicon photodiodes for reflectance pulse oximetry in wearable wireless body sensors

    DEFF Research Database (Denmark)

    Duun, Sune Bro; Haahr, Rasmus Grønbek; Hansen, Ole

    2010-01-01

    The development of annular photodiodes for use in a reflectance pulse oximetry sensor is presented. Wearable and wireless body sensor systems for long-term monitoring require sensors that minimize power consumption. We have fabricated large area 2D ring-shaped silicon photodiodes optimized...

  12. The properties of ITE's silicon avalanche photodiodes within the spectral range used in scintillation detection

    CERN Document Server

    Wegrzecka, I

    1999-01-01

    The design and properties of 3 mm silicon avalanche photodiodes developed at ITE are presented. Their performance parameters within the spectral range applicable in scintillation detection (400-700 nm) are discussed and compared to those for near infrared radiation.

  13. The properties of ITE's silicon avalanche photodiodes within the spectral range used in scintillation detection

    Science.gov (United States)

    Wegrzecka, Iwona; Wegrzecki, Maciej

    1999-04-01

    The design and properties of 3 mm silicon avalanche photodiodes developed at ITE are presented. Their performance parameters within the spectral range applicable in scintillation detection (400-700 nm) are discussed and compared to those for near infrared radiation.

  14. Continuous Holdup Measurements with Silicon P-I-N Photodiodes

    International Nuclear Information System (INIS)

    Bell, Z.W.; Oberer, R.B.; Williams, J.A.; Smith, D.E.; Paulus, M.J.

    2002-01-01

    We report on the behavior of silicon P-I-N photodiodes used to perform holdup measurements on plumbing. These detectors differ from traditional scintillation detectors in that no high-voltage is required, no scintillator is used (gamma and X rays are converted directly by the diode), and they are considerably more compact. Although the small size of the diodes means they are not nearly as efficient as scintillation detectors, the diodes' size does mean that a detector module, including one or more diodes, pulse shaping electronics, analog-to-digital converter, embedded microprocessor, and digital interface can be realized in a package (excluding shielding) the size of a pocket calculator. This small size, coupled with only low-voltage power requirement, completely solid-state realization, and internal control functions allows these detectors to be strategically deployed on a permanent basis, thereby reducing or eliminating the need for manual holdup measurements. In this paper, we report on the measurement of gamma and X rays from 235 U and 238 U contained in steel pipe. We describe the features of the spectra, the electronics of the device and show how a network of them may be used to improve estimates of inventory in holdup

  15. Investigation of silicon/silicon germanium multiple quantum well layers in silicon avalanche photodiodes

    International Nuclear Information System (INIS)

    Loudon, A.Y.

    2002-01-01

    Silicon single photon avalanche diodes (SPADs) are currently utilised in many single photon counting systems due to their high efficiency, fast response times, low voltage operation and potentially low cost. For fibre based applications however (at wavelengths 1.3 and 1.55μm) and eye-safe wavelength applications (>1.4μm), Si devices are not suitable due to their 1.1μm absorption edge and hence greatly reduced absorption above this wavelength. InGaAs/InP or Ge SPADs absorb at these longer wavelengths, but both require cryogenic cooling for low noise operation and III-V integration with conventional Si circuitry is difficult. Si/SiGe is currently attracting great interest for optoelectronic applications and attempts to combine Si avalanche photodiodes with Si/SiGe multiple quantum well absorbing layers have been successful. Here, an effort to utilise this material system has shown an improvement in photon counting efficiency above 1.1μm of more than 30 times compared to an all-Si control device. In addition to its longer wavelength response, this Si/SiGe device has room temperature operation, low cost fabrication and is compatible with conventional Si circuitry. (author)

  16. Silicon photodiode with selective Zr/Si coating for extreme ultraviolet spectral range

    International Nuclear Information System (INIS)

    Aruev, P N; Barysheva, Mariya M; Ber, B Ya; Zabrodskaya, N V; Zabrodskii, V V; Lopatin, A Ya; Pestov, Alexey E; Petrenko, M V; Polkovnikov, V N; Salashchenko, Nikolai N; Sukhanov, V L; Chkhalo, Nikolai I

    2012-01-01

    The procedure of manufacturing silicon photodiodes with an integrated Zr/Si filter for extreme ultraviolet (EUV) spectral range is developed. A setup for measuring the sensitivity profile of detectors with spatial resolution better than 100 μm is fabricated. The optical properties of silicon photodiodes in the EUV and visible spectral ranges are investigated. Some characteristics of SPD-100UV diodes with Zr/Si coating and without it, as well as of AXUV-100 diodes, are compared. In all types of detectors a narrow region beyond the operating aperture is found to be sensitive to the visible light. (photodetectors)

  17. High quantum efficiency annular backside silicon photodiodes for reflectance pulse oximetry in wearable wireless body sensors

    International Nuclear Information System (INIS)

    Duun, Sune; Haahr, Rasmus G; Hansen, Ole; Birkelund, Karen; Thomsen, Erik V

    2010-01-01

    The development of annular photodiodes for use in a reflectance pulse oximetry sensor is presented. Wearable and wireless body sensor systems for long-term monitoring require sensors that minimize power consumption. We have fabricated large area 2D ring-shaped silicon photodiodes optimized for minimizing the optical power needed in reflectance pulse oximetry. To simplify packaging, backside photodiodes are made which are compatible with assembly using surface mounting technology without pre-packaging. Quantum efficiencies up to 95% and area-specific noise equivalent powers down to 30 fW Hz -1/2 cm -1 are achieved. The photodiodes are incorporated into a wireless pulse oximetry sensor system embedded in an adhesive patch presented elsewhere as 'The Electronic Patch'. The annular photodiodes are fabricated using two masked diffusions of first boron and subsequently phosphor. The surface is passivated with a layer of silicon nitride also serving as an optical filter. As the final process, after metallization, a hole in the center of the photodiode is etched using deep reactive ion etch.

  18. Two-dimensional position sensitive silicon photodiode as a charged particle detector

    International Nuclear Information System (INIS)

    Kovacevic, K.; Zadro, M.

    1999-01-01

    A two-dimensional position sensitive silicon photodiode has been tested for measurement of position and energy of charged particles. Position nonlinearity and resolution, as well as energy resolution and ballistic deficit were measured for 5.486 MeV α-particles. The results obtained for different pulse shaping time constants are presented

  19. Three hydrogenated amorphous silicon photodiodes stacked for an above integrated circuit colour sensor

    Energy Technology Data Exchange (ETDEWEB)

    Gidon, Pierre; Giffard, Benoit; Moussy, Norbert; Parrein, Pascale; Poupinet, Ludovic [CEA-LETI, MINATEC, CEA-Grenoble, 17 rue des Martyrs, 38054 Grenoble Cedex 9 (France)

    2010-03-15

    We present theoretical simulation and experimental results of a new colour pixel structure. This pixel catches the light in three stacked amorphous silicon photodiodes encompassed between transparent electrodes. The optical structure has been simulated for signal optimisation. The thickness of each stacked layer is chosen in order to absorb the maximum of light and the three signals allow to linearly calculate the CIE colour coordinates 1 with minimum error and noise. The whole process is compatible with an above integrated circuit (IC) approach. Each photodiode is an n-i-p structure. For optical reason, the upper diode must be controlled down to 25 nm thickness. The first test pixel structure allows a good recovering of colour coordinates. The measured absorption spectrum of each photodiode is in good agreement with our simulations. This specific stack with three photodiodes per pixel totalises two times more signal than an above IC pixel under a standard Bayer pattern 2,3. In each square of this GretagMacbeth chart is the reference colour on the right and the experimentally measured colour on the left with three amorphous silicon photodiodes per pixel. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  20. Scintillation light read-out by thin photodiodes in silicon wells

    CERN Document Server

    Allier, C P; Sarro, P M; Eijk, C W E

    2000-01-01

    Several applications of X-ray and gamma ray imaging detectors, e.g. in medical diagnostics, require millimeter or sub-millimeter spatial resolution and good energy resolution. In order to achieve such features we have proposed a new type of camera, which takes advantage of micromachining technology. It consists of an array of scintillator crystals encapsulated in silicon wells with photodiodes at the bottom. Several parameters of the photodiode need to be optimised: uniformity and efficiency of the light detection, gain, electronic noise and breakdown voltage. In order to evaluate these parameters we have processed 3x3 arrays of 1.8 mm sup 2 , approx 10 mu m thick photodiodes using (1 0 0) wafers etched in a KOH solution. Their optical response at 675 nm wavelength is comparable to that of a 500 mu m thick silicon PIN diode. Their low light detection efficiency is compensated by internal amplification. Several scintillator materials have been positioned in the wells on top of the thin photodiodes, i.e. a 200 ...

  1. Predictable quantum efficient detector based on n-type silicon photodiodes

    Science.gov (United States)

    Dönsberg, Timo; Manoocheri, Farshid; Sildoja, Meelis; Juntunen, Mikko; Savin, Hele; Tuovinen, Esa; Ronkainen, Hannu; Prunnila, Mika; Merimaa, Mikko; Tang, Chi Kwong; Gran, Jarle; Müller, Ingmar; Werner, Lutz; Rougié, Bernard; Pons, Alicia; Smîd, Marek; Gál, Péter; Lolli, Lapo; Brida, Giorgio; Rastello, Maria Luisa; Ikonen, Erkki

    2017-12-01

    The predictable quantum efficient detector (PQED) consists of two custom-made induced junction photodiodes that are mounted in a wedged trap configuration for the reduction of reflectance losses. Until now, all manufactured PQED photodiodes have been based on a structure where a SiO2 layer is thermally grown on top of p-type silicon substrate. In this paper, we present the design, manufacturing, modelling and characterization of a new type of PQED, where the photodiodes have an Al2O3 layer on top of n-type silicon substrate. Atomic layer deposition is used to deposit the layer to the desired thickness. Two sets of photodiodes with varying oxide thicknesses and substrate doping concentrations were fabricated. In order to predict recombination losses of charge carriers, a 3D model of the photodiode was built into Cogenda Genius semiconductor simulation software. It is important to note that a novel experimental method was developed to obtain values for the 3D model parameters. This makes the prediction of the PQED responsivity a completely autonomous process. Detectors were characterized for temperature dependence of dark current, spatial uniformity of responsivity, reflectance, linearity and absolute responsivity at the wavelengths of 488 nm and 532 nm. For both sets of photodiodes, the modelled and measured responsivities were generally in agreement within the measurement and modelling uncertainties of around 100 parts per million (ppm). There is, however, an indication that the modelled internal quantum deficiency may be underestimated by a similar amount. Moreover, the responsivities of the detectors were spatially uniform within 30 ppm peak-to-peak variation. The results obtained in this research indicate that the n-type induced junction photodiode is a very promising alternative to the existing p-type detectors, and thus give additional credibility to the concept of modelled quantum detector serving as a primary standard. Furthermore, the manufacturing of

  2. An amorphous silicon photodiode with 2 THz gain-bandwidth product based on cycling excitation process

    Science.gov (United States)

    Yan, Lujiang; Yu, Yugang; Zhang, Alex Ce; Hall, David; Niaz, Iftikhar Ahmad; Raihan Miah, Mohammad Abu; Liu, Yu-Hsin; Lo, Yu-Hwa

    2017-09-01

    Since impact ionization was observed in semiconductors over half a century ago, avalanche photodiodes (APDs) using impact ionization in a fashion of chain reaction have been the most sensitive semiconductor photodetectors. However, APDs have relatively high excess noise, a limited gain-bandwidth product, and high operation voltage, presenting a need for alternative signal amplification mechanisms of superior properties. As an amplification mechanism, the cycling excitation process (CEP) was recently reported in a silicon p-n junction with subtle control and balance of the impurity levels and profiles. Realizing that CEP effect depends on Auger excitation involving localized states, we made the counter intuitive hypothesis that disordered materials, such as amorphous silicon, with their abundant localized states, can produce strong CEP effects with high gain and speed at low noise, despite their extremely low mobility and large number of defects. Here, we demonstrate an amorphous silicon low noise photodiode with gain-bandwidth product of over 2 THz, based on a very simple structure. This work will impact a wide range of applications involving optical detection because amorphous silicon, as the primary gain medium, is a low-cost, easy-to-process material that can be formed on many kinds of rigid or flexible substrates.

  3. Hybrid graphene/silicon Schottky photodiode with intrinsic gating effect

    Science.gov (United States)

    Di Bartolomeo, Antonio; Luongo, Giuseppe; Giubileo, Filippo; Funicello, Nicola; Niu, Gang; Schroeder, Thomas; Lisker, Marco; Lupina, Grzegorz

    2017-06-01

    We propose a hybrid device consisting of a graphene/silicon (Gr/Si) Schottky diode in parallel with a Gr/SiO2/Si capacitor for high-performance photodetection. The device, fabricated by transfer of commercial graphene on low-doped n-type Si substrate, achieves a photoresponse as high as 3 \\text{A} {{\\text{W}}-1} and a normalized detectivity higher than 3.5× {{10}12} \\text{cm} \\text{H}{{\\text{z}}1/2} {{\\text{W}}-1} in the visible range. It exhibits a photocurrent exceeding the forward current because photo-generated minority carriers, accumulated at Si/SiO2 interface of the Gr/SiO2/Si capacitor, diffuse to the Gr/Si junction. We show that the same mechanism, when due to thermally generated carriers, although usually neglected or disregarded, causes the increased leakage often measured in Gr/Si heterojunctions. We perform extensive I-V and C-V characterization at different temperatures and we measure a zero-bias Schottky barrier height of 0.52 eV at room temperature, as well as an effective Richardson constant A **  =  4× {{10}-5} \\text{A} \\text{c}{{\\text{m}}-2} {{\\text{K}}-2} and an ideality factor n≈ 3.6 , explained by a thin (<1 nm) oxide layer at the Gr/Si interface.

  4. The role of the substrate in Graphene/Silicon photodiodes

    Science.gov (United States)

    Luongo, G.; Giubileo, F.; Iemmo, L.; Di Bartolomeo, A.

    2018-01-01

    The Graphene/Silicon (Gr/Si) junction can function as a Schottky diode with performances strictly related to the quality of the interface. Here, we focus on the substrate geometry and on its effects on Gr/Si junction physics. We fabricate and study the electrical and optical behaviour of two types of devices: one made of a Gr/Si planar junction, the second realized with graphene on an array of Si nanotips. We show that the Gr/Si flat device exhibits a reverse photocurrent higher than the forward current and achieves a photoresponsivity of 2.5 A/W. The high photoresponse is due to the charges photogenerated in Si below a parasitic graphene/SiO2/Si structure, which are injected into the Gr/Si junction region. The other device with graphene on Si-tips displays a reverse current that grows exponentially with the bias. We explain this behaviour by taking into account the tip geometry of the substrate, which magnifies the electric field and shifts the Fermi level of graphene, thus enabling fine-tuning of the Schottky barrier height. The Gr/Si-tip device achieves a higher photoresponsivity, up to 3 A/W, likely due to photocharge internal multiplication.

  5. Generation efficiency of single-photon current pulses in the Geiger mode of silicon avalanche photodiodes

    International Nuclear Information System (INIS)

    Verkhovtseva, A. V.; Gergel, V. A.

    2009-01-01

    Statistical fluctuations of the avalanche's multiplication efficiency were studied as applied to the single-photon (Geiger) mode of avalanche photodiodes. The distribution function of partial multiplication factors with an anomalously wide (of the order of the average) dispersion was obtained. Expressions for partial feedback factors were derived in terms of the average gain and the corresponding dependences on the diode's overvoltage were calculated. Final expressions for the photon-electric pulse's conversion were derived by averaging corresponding formulas over the coordinate of initiating photoelectron generation using the functions of optical photon absorption in silicon.

  6. Miniature silicon photodiodes for photon and electron radiation dosimetry in therapeutical applications

    International Nuclear Information System (INIS)

    Gilar, O.; Petr, I.

    1986-01-01

    The silicon diode is manufactured from P type silicon, the P layer is implanted with boron atoms and the N layer with phosphorus atoms. The diode dimensions are 2x2x0.2 mm. It is encased in elastic tissue-equivalent material. The electrodes are from an Al foil. The diode can be used as an in-vivo dosemeter in human body cavities. When irradiated, it supplies information on the instantaneous dose rate at a given point and on the dose cumulated over a certain time. Its current response to gamma radiation kerma rate is linear, directional sensitivity is isotropic. Temperature sensitivity of the photodiode is shown graphically for the range 20 to 40 degC, and the depth dose distribution measured in a water phantom is given for 6, 12 and 20 MeV photons and electrons. The diode energy dependence shows increased sensitivity to low-energy photons. (M.D.)

  7. High-speed detection at two micrometres with monolithic silicon photodiodes

    Science.gov (United States)

    Ackert, Jason J.; Thomson, David J.; Shen, Li; Peacock, Anna C.; Jessop, Paul E.; Reed, Graham T.; Mashanovich, Goran Z.; Knights, Andrew P.

    2015-06-01

    With continued steep growth in the volume of data transmitted over optical networks there is a widely recognized need for more sophisticated photonics technologies to forestall a ‘capacity crunch’. A promising solution is to open new spectral regions at wavelengths near 2 μm and to exploit the long-wavelength transmission and amplification capabilities of hollow-core photonic-bandgap fibres and the recently available thulium-doped fibre amplifiers. To date, photodetector devices for this window have largely relied on III-V materials or, where the benefits of integration with silicon photonics are sought, GeSn alloys, which have been demonstrated thus far with only limited utility. Here, we describe a silicon photodiode operating at 20 Gbit s-1 in this wavelength region. The detector is compatible with standard silicon processing and is integrated directly with silicon-on-insulator waveguides, which suggests future utility in silicon-based mid-infrared integrated optics for applications in communications.

  8. Performance of a PET detector module utilizing an array of silicon photodiodes to identify the crystal of interaction

    International Nuclear Information System (INIS)

    Moses, W.W.; Derenzo, S.E.; Nutt, R.; Digby, W.M.; Williams, C.W.; Andreaco, M.

    1993-01-01

    The authors initial performance results for a new multi-layer PET detector module consisting of an array of 3 mm square by 30 mm deep BGO crystals coupled on one end to a single photomultiplier tube and on the opposite end to an array of 3 mm square silicon photodiodes. The photomultiplier tube provides an accurate timing pulse and energy discrimination for all the crystals in the module, while the silicon photodiodes identify the crystal of interaction. When a single BGO crystal at +25 C is excited with 511 keV photons, the authors measure a photodiode signal centered at 700 electrons (e - ) with noise of 375 e - fwhm. When a four crystal/photodiode module is excited with a collimated line source of 511 keV photons, the crystal of interaction is correctly identified 82% of the time. The misidentification rate can be greatly reduced and an 8 x 8 crystal/photodiode module constructed by using thicker depletion layer photodiodes or cooling to 0 C

  9. Optical performance of B-layer ultra-shallow-junction silicon photodiodes in the VUV spectral range

    NARCIS (Netherlands)

    Shi, L.; Sarubbi, F.; Nanver, L.K.; Kroth, U.; Gottwald, A.; Nihtianov, S.

    2010-01-01

    In recent work, a novel silicon-based photodiode technology was reported to be suitable for producing radiation detectors for 193 nm deep-ultraviolet light and for the extreme-ultraviolet (EUV) spectral range. The devices were developed and fabricated at the Delft Institute of Microsystems and

  10. Predictions of silicon avalanche photodiode detector performance in water vapor differential absorption lidar

    Science.gov (United States)

    Kenimer, R. L.

    1988-01-01

    Performance analyses are presented which establish that over most of the range of signals expected for a down-looking differential absorption lidar (DIAL) operated at 16 km the silicon avalanche photodiode (APD) is the preferred detector for DIAL measurements of atmospheric water vapor in the 730 nm spectral region. The higher quantum efficiency of the APD's, (0.8-0.9) compared to a photomultiplier's (0.04-0.18) more than offsets the higher noise of an APD receiver. In addition to offering lower noise and hence lower random error the APD's excellent linearity and impulse recovery minimize DIAL systematic errors attributable to the detector. Estimates of the effect of detector system parameters on overall random and systematic DIAL errors are presented, and performance predictions are supported by laboratory characterization data for an APD receiver system.

  11. The performance of photon counting imaging with a Geiger mode silicon avalanche photodiode

    International Nuclear Information System (INIS)

    Qu, Hui-Ming; Zhang, Yi-Fan; Ji, Zhong-Jie; Chen, Qian

    2013-01-01

    In principle, photon counting imaging can detect a photon. With the development of low-level-light image intensifier techniques and low-level-light detection devices, photon counting imaging can now detect photon images under extremely low illumination. Based on a Geiger mode silicon avalanche photodiode single photon counter, an experimental system for photon counting imaging was built through two-dimensional scanning of a SPAD (single photon avalanche diode) detector. The feasibility of the imaging platform was validated experimentally. Two images with different characteristics, namely, the USAF 1951 resolution test panel and the image of Lena, were chosen to evaluate the imaging performance of the experimental system. The results were compared and analysed. The imaging properties under various illumination and scanning steps were studied. The lowest illumination limit of the SPAD photon counting imaging was determined. (letter)

  12. Assembly and test of a silicon photodiode and a selenium cell in a laboratory photometer

    International Nuclear Information System (INIS)

    Mejias Espinoza, Hugo Alberto

    2008-01-01

    A comparison procedure is performed between a selenium cell and a silicon photodiode for measuring the relative amount of light in a laboratory photometer. The measurements were performed with the existing selenium cell in photometer of high sensitivity to see the behavior at different distances. Measurement instruments have been handled with extremely careful in the calibration. Measurements with neutral density filters have been unsuccessful, the final value which has given the multimeter does not vary fairly with the values of the neutral density filters. An improved transducer must be provided to the photometer circuit of high sensitivity to improve the graphics. A current to voltage converter must be supplemented to the phototransistor. Device response has improved to minimal changes in lighting [es

  13. Practical photon number detection with electric field-modulated silicon avalanche photodiodes.

    Science.gov (United States)

    Thomas, O; Yuan, Z L; Shields, A J

    2012-01-24

    Low-noise single-photon detection is a prerequisite for quantum information processing using photonic qubits. In particular, detectors that are able to accurately resolve the number of photons in an incident light pulse will find application in functions such as quantum teleportation and linear optics quantum computing. More generally, such a detector will allow the advantages of quantum light detection to be extended to stronger optical signals, permitting optical measurements limited only by fluctuations in the photon number of the source. Here we demonstrate a practical high-speed device, which allows the signals arising from multiple photon-induced avalanches to be precisely discriminated. We use a type of silicon avalanche photodiode in which the lateral electric field profile is strongly modulated in order to realize a spatially multiplexed detector. Clearly discerned multiphoton signals are obtained by applying sub-nanosecond voltage gates in order to restrict the detector current.

  14. A silicon avalanche photodiode detector circuit for Nd:YAG laser scattering

    International Nuclear Information System (INIS)

    Hsieh, C.L.; Haskovec, J.; Carlstrom, T.N.; DeBoo, J.C.; Greenfield, C.M.; Snider, R.T.; Trost, P.

    1990-06-01

    A silicon avalanche photodiode with an internal gain of about 50 to 100 is used in a temperature controlled environment to measure the Nd:YAG laser Thomson scattered spectrum in the wavelength range from 700 to 1150 nm. A charge sensitive preamplifier has been developed for minimizing the noise contribution from the detector electronics. Signal levels as low as 20 photoelectrons (S/N = 1) can be detected. Measurements show that both the signal and the variance of the signal vary linearly with the input light level over the range of interest, indicating Poisson statistics. The signal is processed using a 100 ns delay line and a differential amplifier which subtracts the low frequency background light component. The background signal is amplified with a computer controlled variable gain amplifier and is used for an estimate of the measurement error, calibration, and Z eff measurements of the plasma. The signal processing has been analyzed using a theoretical model to aid the system design and establish the procedure for data error analysis. 4 refs., 5 figs

  15. Automated and inexpensive method to manufacture solid- state nanopores and micropores in robust silicon wafers

    International Nuclear Information System (INIS)

    Vega, M; Lasorsa, C; Lerner, B; Perez, M; Granell, P

    2016-01-01

    In this work an easy, reproducible and inexpensive technique for the production of solid state nanopores and micropores using silicon wafer substrate is proposed. The technique is based on control of pore formation, by neutralization etchant (KOH) with a strong acid (HCl). Thus, a local neutralization is produced around the nanopore, which stops the silicon etching. The etching process was performed with 7M KOH at 80°C, where 1.23µm/min etching speed was obtained, similar to those published in literature. The control of the pore formation with the braking acid method was done using 12M HCl and different extreme conditions: i) at 25°C, ii) at 80°C and iii) at 80°C applying an electric potential. In these studies, it was found that nanopores and micropores can be obtained automatically and at a low cost. Additionally, the process was optimized to obtain clean silicon wafers after the pore fabrication process. This method opens the possibility for an efficient scale-up from laboratory production. (paper)

  16. Automated and inexpensive method to manufacture solid- state nanopores and micropores in robust silicon wafers

    Science.gov (United States)

    Vega, M.; Granell, P.; Lasorsa, C.; Lerner, B.; Perez, M.

    2016-02-01

    In this work an easy, reproducible and inexpensive technique for the production of solid state nanopores and micropores using silicon wafer substrate is proposed. The technique is based on control of pore formation, by neutralization etchant (KOH) with a strong acid (HCl). Thus, a local neutralization is produced around the nanopore, which stops the silicon etching. The etching process was performed with 7M KOH at 80°C, where 1.23µm/min etching speed was obtained, similar to those published in literature. The control of the pore formation with the braking acid method was done using 12M HCl and different extreme conditions: i) at 25°C, ii) at 80°C and iii) at 80°C applying an electric potential. In these studies, it was found that nanopores and micropores can be obtained automatically and at a low cost. Additionally, the process was optimized to obtain clean silicon wafers after the pore fabrication process. This method opens the possibility for an efficient scale-up from laboratory production.

  17. Development of a PET detector module incorporating a silicon photodiode array

    International Nuclear Information System (INIS)

    Rosenfeld, A.B.; Takacs, G.J.; Lerch, M.L.F.; Simmonds, P.E.

    2000-01-01

    Full text: We are developing a new Positron Emission Tomography (PET) detection sub-module with depth of interaction capability. The new sub-module is simple and robust to minimise module assembly complications and is completely independent of photomultiplier tubes. The new sub-module has also been designed to maximise its flexibility for easy sub-module coupling so as to form a complete, customised, detection module to be used in PET scanners dedicated to human brain and breast, and small animal studies. Blue enhanced, silicon 8x8 detector arrays are used to read out the scintillation crystals, and form the basis of the new module. The new detectors were designed by the Centre for Medical Radiation Physics (CMRP) at the University of Wollongong in collaboration with the High Energy Physics Department, University of Melbourne and produced by SPO D etector , Ukraine. Complementing the work on the silicon photodetectors, we have also carried out simulations of the propagation of the scintillation light in the crystals, and the effect of crystal dimensions and surface treatment on the distribution of light detected by the photodiode array. The distribution of light over the photodiodes has then been used to test various algorithms for calculating the point of interaction of the gamma ray in the crystal. Simulations of the light propagation show that for a crystal of dimensions 25mm x 25mm x 3mm, it is possible to determine the point of interaction in 2 dimensions with an average accuracy of just over 0.5mm. The resulting photon distribution detected by the array. The surface treatment, while having a large effect on the light output, does not have a great effect on the accuracy. If these dimensions change to 25mm x 25mm x 6mm then the surface conditions have a greater effect on the accuracy. It is possible however, with careful surface treatment, to achieve an accuracy of around 0.6mm, only marginally worse than the case for the 3mm thick crystal. Gamma ray

  18. Feasibility study into the use of silicon photo-diodes for the alignment of collimated X-rays on the SRS

    CERN Document Server

    Buffey, S G

    1999-01-01

    Dynamic alignment of beam on the crystal during data collection was studied. Development of silicon photo-diode detectors for the vacuum ultraviolet and soft X-ray spectral regions has led to the use of such devices as beam alignment tools for Protein Crystallography beamlines on the Synchrotron Radiation Source at Daresbury. Quadrant photo-diodes are used to provide signals proportional to the number of photons hitting each photo-diode, these are amplified, digitised and then summed to give the x-y position of the beam centre. (author)

  19. 2 μm wavelength range InP-based type-II quantum well photodiodes heterogeneously integrated on silicon photonic integrated circuits.

    Science.gov (United States)

    Wang, Ruijun; Sprengel, Stephan; Muneeb, Muhammad; Boehm, Gerhard; Baets, Roel; Amann, Markus-Christian; Roelkens, Gunther

    2015-10-05

    The heterogeneous integration of InP-based type-II quantum well photodiodes on silicon photonic integrated circuits for the 2 µm wavelength range is presented. A responsivity of 1.2 A/W at a wavelength of 2.32 µm and 0.6 A/W at 2.4 µm wavelength is demonstrated. The photodiodes have a dark current of 12 nA at -0.5 V at room temperature. The absorbing active region of the integrated photodiodes consists of six periods of a "W"-shaped quantum well, also allowing for laser integration on the same platform.

  20. Microspot-based ELISA in microfluidics: chemiluminescence and colorimetry detection using integrated thin-film hydrogenated amorphous silicon photodiodes.

    Science.gov (United States)

    Novo, Pedro; Prazeres, Duarte Miguel França; Chu, Virginia; Conde, João Pedro

    2011-12-07

    Microfluidic technology has the potential to decrease the time of analysis and the quantity of sample and reactants required in immunoassays, together with the potential of achieving high sensitivity, multiplexing, and portability. A lab-on-a-chip system was developed and optimized using optical and fluorescence microscopy. Primary antibodies are adsorbed onto the walls of a PDMS-based microchannel via microspotting. This probe antibody is then recognised using secondary FITC or HRP labelled antibodies responsible for providing fluorescence or chemiluminescent and colorimetric signals, respectively. The system incorporated a micron-sized thin-film hydrogenated amorphous silicon photodiode microfabricated on a glass substrate. The primary antibody spots in the PDMS-based microfluidic were precisely aligned with the photodiodes for the direct detection of the antibody-antigen molecular recognition reactions using chemiluminescence and colorimetry. The immunoassay takes ~30 min from assay to the integrated detection. The conditions for probe antibody microspotting and for the flow-through ELISA analysis in the microfluidic format with integrated detection were defined using antibody solutions with concentrations in the nM-μM range. Sequential colorimetric or chemiluminescence detection of specific antibody-antigen molecular recognition was quantitatively detected using the photodiode. Primary antibody surface densities down to 0.182 pmol cm(-2) were detected. Multiplex detection using different microspotted primary antibodies was demonstrated.

  1. Low-energy X-ray and gamma spectrometry using silicon photodiodes

    International Nuclear Information System (INIS)

    Silva, Iran Jose Oliveira da

    2000-08-01

    The use of semiconductor detectors for radiation detection has increased in recent years due to advantages they present in comparison to other types of detectors. As the working principle of commercially available photodiodes is similar to the semiconductor detector, this study was carried out to evaluate the use of Si photodiodes for low energy x-ray and gamma spectrometry. The photodiodes investigated were SFH-205, SFH-206, BPW-34 and XRA-50 which have the following characteristics: active area of 0,07 cm 2 and 0,25 cm 2 , thickness of the depletion ranging from 100 to 200 μm and junction capacitance of 72 pF. The photodiode was polarized with a reverse bias and connected to a charge sensitive pre-amplifier, followed by a amplifier and multichannel pulse analyzer. Standard radiation source used in this experiment were 241 Am, 109 Cd, 57 Co and 133 Ba. The X-ray fluorescence of lead and silver were also measured through K- and L-lines. All the measurements were made with the photodiodes at room temperature.The results show that the responses of the photodiodes very linear by the x-ray energy and that the energy resolution in FWHM varied between 1.9 keV and 4.4 keV for peaks corresponding to 11.9 keV to 59 keV. The BPW-34 showed the best energy resolution and the lower dark current. The full-energy peak efficiency was also determined and it was observed that the peak efficiency decreases rapidly above 50 keV. The resolution and efficiency are similar to the values obtained with other semiconductor detectors, evidencing that the photodiodes used in that study can be used as a good performance detector for low energy X-ray and gamma spectrometry. (author)

  2. Readout and characterisation of new silicon pixel photodiode array for use in PET

    International Nuclear Information System (INIS)

    Hooper, P.; Ward, G.; Lerch, R.; Rozenfeld, A.

    2002-01-01

    Full text: Positron emission tomography (PET) is a functional imaging tool, which is able to quantify physiological, and biochemical processes in vivo using short-lived cyclotron-produced radiotracers. The main physical principle of PET is the simultaneous measurement of two 511 keV photons which are emitted in opposite directions following the annihilation of a positron in tissue. The accuracy of tracking these photons determines the accuracy of localising the radiotracer in the body, which is referred to as the spatial resolution of the system. Compared with conventional single photon imaging with gamma cameras, PET provides superior spatial resolution and sensitivity. However, compared with anatomical imaging techniques, the spatial resolution remains relatively poor at approximately 4-6 mm full width at half maximum (FWHM), compared with 1 mm FWHM for MRI. The Centre for Medical Radiation Physics at the University of Wollongong is developing a new Positron Emission Tomography (PET) detection sub-module that will significantly improve the spatial resolution of PET. The new sub-module design is simple and robust to minimise module assembly complications and is completely independent of photomultiplier tubes. The new sub-module has also been designed to maximise its flexibility for easy sub-module coupling so as to form a complete, customised, detection module to be used in PET scanners dedicated to human brain and breast, and small animal studies. A new computer controlled gantry allows the system to be used for PET and SPECT applications. Silicon 8x8 detector arrays have been developed by CMRP and will be optically coupled scintillation crystals and readout using the VIKING tM hybrid preamplifier chip to form the basis of the new module Characterisation of the pixel photodiode array has been performed to check the uniformity of the response of the array. This characterisation has been done using a pulsed, near infra-red laser diode system and alpha particles

  3. Spectral dependence of the main parameters of ITE silicon avalanche photodiodes

    Science.gov (United States)

    Wegrzecka, Iwona; Grynglas, Maria; Wegrzecki, Maciej

    2001-08-01

    New applications for avalanche photodiodes (APDs) as in systems using visible radiation, have prompted the need for the evaluation of detection properties of ITE APDs in the 400 divided by 700 nm spectral range. The paper presents the method and result of studies on the spectral dependence of the gain, dark and noise currents, sensitivity and excess noise factor of ITE APDs. The studies have shown that ITE APDs optimized for the near IR radiation can be effectively applied in the detection of radiation above the 500 nm wavelength.

  4. Miniaturized flow cytometer with 3D hydrodynamic particle focusing and integrated optical elements applying silicon photodiodes

    NARCIS (Netherlands)

    Rosenauer, M.; Buchegger, W.; Finoulst, I.; Verhaert, P.D.E.M.; Vellekoop, M.

    2010-01-01

    In this study, the design, realization and measurement results of a novel optofluidic system capable of performing absorbance-based flow cytometric analysis is presented. This miniaturized laboratory platform, fabricated using SU-8 on a silicon substrate, comprises integrated polymer-based

  5. Radiation Detection Measurements with a New 'Buried Junction' Silicon Avalanche Photodiode

    CERN Document Server

    Lecomte, R; Rouleau, D; Dautet, H; McIntyre, R J; McSween, D; Webb, P

    1999-01-01

    An improved version of a recently developed 'Buried Junction' avalanche photodiode (APD), designed for use with scintillators, is described and characterized. This device, also called the 'Reverse APD', is designed to have a wide depletion layer and thus low capacitance, but to have high gain only for e-h pairs generated within the first few microns of the depletion layer. Thus it has high gain for light from scintillators emitting in the 400-600 nm range, with relatively low dark current noise and it is relatively insensitive to minimum ionizing particles (MIPs). An additional feature is that the metallurgical junction is at the back of the wafer, leaving the front surface free to be coupled to a scintillator without fear of junction contamination. The modifications made in this device, as compared with the earlier diode, have resulted in a lower excess noise factor, lower dark current, and much-reduced trapping. The electrical and optical characteristics of this device are described and measurements of ener...

  6. A low-cost, ultra-fast and ultra-low noise preamplifier for silicon avalanche photodiodes

    Science.gov (United States)

    Gasmi, Khaled

    2018-02-01

    An ultra-fast and ultra-low noise preamplifier for amplifying the fast and weak electrical signals generated by silicon avalanche photodiodes has been designed and developed. It is characterized by its simplicity, compactness, reliability and low cost of construction. A very wide bandwidth of 300 MHz, a very good linearity from 1 kHz to 280 MHz, an ultra-low noise level at the input of only 1.7 nV Hz-1/2 and a very good stability are its key features. The compact size (70 mm  ×  90 mm) and light weight (45 g), as well as its excellent characteristics, make this preamplifier very competitive compared to any commercial preamplifier. The preamplifier, which is a main part of the detection system of a homemade laser remote sensing system, has been successfully tested. In addition, it is versatile and can be used in any optical detection system requiring high speed and very low noise electronics.

  7. Silicon avalanche photodiodes on the base of metal-resistor-semiconductor (MRS) structures

    CERN Document Server

    Saveliev, V

    2000-01-01

    The development of a high quantum efficiency, fast photodetector, with internal gain amplification for the wavelength range 450-600 nm is one of the critical issues for experimental physics - registration of low-intensity light photons flux. The new structure of Silicon Avalanche Detectors with high internal amplification (10 sup 5 -10 sup 6) has been designed, manufactured and tested for registration of visible light photons and charge particles. The main features of Metal-Resistor-Semiconductor (MRS) structures are the high charge multiplication in nonuniform electric field near the 'needle' pn-junction and negative feedback for stabilization of avalanche process due to resistive layer.

  8. Capacitance-voltage investigation of silicon photodiodes damaged by MeV energy light ions

    International Nuclear Information System (INIS)

    Kalinka, G.; Simon, A.; Novak, M.; Kiss, A.Z.

    2006-01-01

    Complete text of publication follows. Nuclear radiation creates not only deep centers, but in addition influences shallow dopant concentration in semiconductors, as well. At a given temperature the maximum frequency a center can respond to depends on its energy level, therefore the capacitance-voltage (C-V) characteristics of radiation damaged semiconductor diodes should ideally be measured as function of frequency in order to obtain the physical and energy depth distribution of ionized centers [1,2]. In our experiments C-V plots of MeV energy ion irradiated photodiodes were taken at fixed 1 kHz frequency, which is low enough to be sensitive at room temperature to some of the deep levels expected. During, for example, an irradiation with 5.5 MeV α particles the capacitance of a p + nn + diode increased significantly at low voltages, but showed rather small changes at higher ones. The former turned out to be merely related to a decrease of the built in voltage, corresponding to a lifetime to relaxation type transition of the semiconductor [3]. Rescaling C-V data for this change, the remaining, actual capacitance changes could be interpreted as related to nuclear recoil caused damage located around the end of particle tracks. C-V technique has also been used for follow up investigation of spontaneous self annealing at room temperature of irradiated samples. This is shown here by plotting capacitance data normalized to their virgin values as function of depletion depth for irradiation with 430 keV protons, whose range is about 5 μm. The sensitivity of the method is illustrated for low fluence of 6.5 MeV oxygen, whose range is 5 μm, too, and where the normalization is now made to data taken one week after the irradiation. Acknowledgement This work was supported by the Hungarian Research and Technology Innovation Fund and the Croatian Ministry of Science, Education and Sports within the framework of the Hungarian-Croatian Intergovernmental Science and Technology Co

  9. Polycrystalline silicon ring resonator photodiodes in a bulk complementary metal-oxide-semiconductor process.

    Science.gov (United States)

    Mehta, Karan K; Orcutt, Jason S; Shainline, Jeffrey M; Tehar-Zahav, Ofer; Sternberg, Zvi; Meade, Roy; Popović, Miloš A; Ram, Rajeev J

    2014-02-15

    We present measurements on resonant photodetectors utilizing sub-bandgap absorption in polycrystalline silicon ring resonators, in which light is localized in the intrinsic region of a p+/p/i/n/n+ diode. The devices, operating both at λ=1280 and λ=1550  nm and fabricated in a complementary metal-oxide-semiconductor (CMOS) dynamic random-access memory emulation process, exhibit detection quantum efficiencies around 20% and few-gigahertz response bandwidths. We observe this performance at low reverse biases in the range of a few volts and in devices with dark currents below 50 pA at 10 V. These results demonstrate that such photodetector behavior, previously reported by Preston et al. [Opt. Lett. 36, 52 (2011)], is achievable in bulk CMOS processes, with significant improvements with respect to the previous work in quantum efficiency, dark current, linearity, bandwidth, and operating bias due to additional midlevel doping implants and different material deposition. The present work thus offers a robust realization of a fully CMOS-fabricated all-silicon photodetector functional across a wide wavelength range.

  10. A discrete model of the development and relaxation of a local microbreakdown in silicon avalanche photodiodes operating in the Geiger mode

    International Nuclear Information System (INIS)

    Vanyushin, I. V.; Gergel, V. A.; Gontar', V. M.; Zimoglyad, V. A.; Tishin, Yu. I.; Kholodnov, V. A.; Shcheleva, I. M.

    2007-01-01

    A new discrete theoretical model of the development and relaxation of a local microbreakdown in silicon avalanche photodiodes operating in the Geiger mode is developed. It is shown that the spreading resistance in the substrate profoundly affects both the amplitude of a single-photon electrical pulse and the possibility of attaining the steady-state form of the avalanche breakdown excluding the Geiger mode of the photodiode's operation. The model is employed to interpret the experimental data obtained using test single-photon cells of avalanche photodiodes fabricated on the basis of the 0.25-μm silicon technology with the use of deep implantation to form the region of avalanche multiplication for the charge carriers. Excellent functional properties of the studied type of the single-photon (Geiger) cell are noted. A typical amplitude characteristic of the cell for optical radiation with the wavelength λ = 0.56 μm in the irradiance range of 10 -3 -10 2 lx is presented; this characteristic indicates that the quantum efficiency of photoconversion is extremely high

  11. Mediating broadband light into graphene–silicon Schottky photodiodes by asymmetric silver nanospheroids: effect of shape anisotropy

    Science.gov (United States)

    Bhardwaj, Shivani; Parashar, Piyush K.; Roopak, Sangita; Ji, Alok; Uma, R.; Sharma, R. P.

    2018-05-01

    Designing thinner, more efficient and cost-effective 2D materials/silicon Schottky photodiodes using the plasmonic concept is one of the most recent quests for the photovoltaic research community. This work demonstrates the enhanced performance of graphene–Si Schottky junction solar cells by introducing asymmetric spheroidal shaped Ag nanoparticles (NPs) embedded in a graphene monolayer (GML). The optical signatures of these Ag NPs (oblate, ortho-oblate, prolate and ortho-prolate) have been analyzed by discrete dipole approximation in terms of extinction efficiency and surface plasmon resonance tunability, against the quasi-static approximation. The spatial field distribution is enhanced by optimizing the size (a eff  =  100 nm) and aspect ratio (0.4) for all of the utilized Ag NPs with an optimized graphene environment (t  =  0.1 nm). An improvement of photon absorption in the thin Si wafer for the polychromatic spectral region (λ ~ 300–1100 nm) under an AM 1.5 G solar spectrum has been observed. This resulted in a photocurrent enhancement from 7.98 mA cm‑2 to 10.0 mA cm‑2 for oblate-shaped NPs integrated into GML/Si Schottky junction solar cells as compared to the bare cell. The structure used in this study to improve the graphene–Si Schottky junction’s performance is also advantageous for other graphene-like 2D material-based Schottky devices.

  12. Normal incidence spectrophotometer using high density transmission grating technology and highly efficiency silicon photodiodes for absolute solar EUV irradiance measurements

    Science.gov (United States)

    Ogawa, H. S.; Mcmullin, D.; Judge, D. L.; Korde, R.

    1992-01-01

    New developments in transmission grating and photodiode technology now make it possible to realize spectrometers in the extreme ultraviolet (EUV) spectral region (wavelengths less than 1000 A) which are expected to be virtually constant in their diffraction and detector properties. Time dependent effects associated with reflection gratings are eliminated through the use of free standing transmission gratings. These gratings together with recently developed and highly stable EUV photodiodes have been utilized to construct a highly stable normal incidence spectrophotometer to monitor the variability and absolute intensity of the solar 304 A line. Owing to its low weight and compactness, such a spectrometer will be a valuable tool for providing absolute solar irradiance throughout the EUV. This novel instrument will also be useful for cross-calibrating other EUV flight instruments and will be flown on a series of Hitchhiker Shuttle Flights and on SOHO. A preliminary version of this instrument has been fabricated and characterized, and the results are described.

  13. X-ray-to-current signal conversion characteristics of trench-structured photodiodes for direct-conversion-type silicon X-ray sensor

    International Nuclear Information System (INIS)

    Ariyoshi, Tetsuya; Funaki, Shota; Sakamoto, Kenji; Baba, Akiyoshi; Arima, Yutaka

    2017-01-01

    To reduce the radiation dose required in medical X-ray diagnoses, we propose a high-sensitivity direct-conversion-type silicon X-ray sensor that uses trench-structured photodiodes. This sensor is advantageous in terms of its long device lifetime, noise immunity, and low power consumption because of its low bias voltage. With this sensor, it is possible to detect X-rays with almost 100% efficiency; sensitivity can therefore be improved by approximately 10 times when compared with conventional indirect-conversion-type sensors. In this study, a test chip was fabricated using a single-poly single-metal 0.35 μm process. The formed trench photodiodes for the X-ray sensor were approximately 170 and 300 μm deep. At a bias voltage of 25 V, the absorbed X-ray-to-current signal conversion efficiencies were 89.3% (theoretical limit; 96.7%) at a trench depth of 170 μm and 91.1% (theoretical limit; 94.3%) at a trench depth of 300 μm. (author)

  14. Nuclear resonant scattering measurements on (57)Fe by multichannel scaling with a 64-pixel silicon avalanche photodiode linear-array detector.

    Science.gov (United States)

    Kishimoto, S; Mitsui, T; Haruki, R; Yoda, Y; Taniguchi, T; Shimazaki, S; Ikeno, M; Saito, M; Tanaka, M

    2014-11-01

    We developed a silicon avalanche photodiode (Si-APD) linear-array detector for use in nuclear resonant scattering experiments using synchrotron X-rays. The Si-APD linear array consists of 64 pixels (pixel size: 100 × 200 μm(2)) with a pixel pitch of 150 μm and depletion depth of 10 μm. An ultrafast frontend circuit allows the X-ray detector to obtain a high output rate of >10(7) cps per pixel. High-performance integrated circuits achieve multichannel scaling over 1024 continuous time bins with a 1 ns resolution for each pixel without dead time. The multichannel scaling method enabled us to record a time spectrum of the 14.4 keV nuclear radiation at each pixel with a time resolution of 1.4 ns (FWHM). This method was successfully applied to nuclear forward scattering and nuclear small-angle scattering on (57)Fe.

  15. 10 μ m-thick four-quadrant transmissive silicon photodiodes for beam position monitor application: electrical characterization and gamma irradiation effects

    Science.gov (United States)

    Rafí, J. M.; Pellegrini, G.; Quirion, D.; Hidalgo, S.; Godignon, P.; Matilla, O.; Juanhuix, J.; Fontserè, A.; Molas, B.; Pothin, D.; Fajardo, P.

    2017-01-01

    Silicon photodiodes are very useful devices as X-ray beam monitors in synchrotron radiation beamlines. Owing to Si absorption, devices thinner than 10 μ m are needed to achieve transmission over 90% for energies above 10 keV . In this work, new segmented four-quadrant diodes for beam alignment purposes are fabricated on both ultrathin (10 μ m-thick) and bulk silicon substrates. Four-quadrant diodes implementing different design parameters as well as auxiliary test structures (single diodes and MOS capacitors) are studied. An extensive electrical characterization, including current-voltage (I-V) and capacitance-voltage (C-V) techniques, is carried out on non-irradiated and gamma-irradiated devices up to 100 Mrad doses. Special attention is devoted to the study of radiation-induced charge build-up in diode interquadrant isolation dielectric, as well as its impact on device interquadrant resistance. Finally, the devices have been characterized with an 8 keV laboratory X-ray source at 108 ph/s and in BL13-XALOC ALBA Synchroton beamline with 1011 ph/s and energies from 6 to 16 keV . Sensitivity, spatial resolution and uniformity of the devices have been evaluated.

  16. Improved bandwidth and quantum efficiency in silicon photodiodes using photon-manipulating micro/nanostructures operating in the range of 700-1060 nm

    Science.gov (United States)

    Cansizoglu, Hilal; Gao, Yang; Ghandiparsi, Soroush; Kaya, Ahmet; Perez, Cesar Bartolo; Mayet, Ahmed; Ponizovskaya Devine, Ekaterina; Cansizoglu, Mehmet F.; Yamada, Toshishige; Elrefaie, Aly F.; Wang, Shih-Yuan; Islam, M. Saif

    2017-08-01

    Nanostructures allow broad spectrum and near-unity optical absorption and contributed to high performance low-cost Si photovoltaic devices. However, the efficiency is only a few percent higher than a conventional Si solar cell with thicker absorption layers. For high speed surface illuminated photodiodes, the thickness of the absorption layer is critical for short transit time and RC time. Recently a CMOS-compatible micro/nanohole silicon (Si) photodiode (PD) with more than 20 Gb/s data rate and with 52 % quantum efficiency (QE) at 850 nm was demonstrated. The achieved QE is over 400% higher than a similar Si PD with the same thickness but without absorption enhancement microstructure holes. The micro/nanoholes increases the QE by photon trapping, slow wave effects and generate a collective assemble of modes that radiate laterally, resulting in absorption enhancement and therefore increase in QE. Such Si PDs can be further designed to enhance the bandwidth (BW) of the PDs by reducing the device capacitance with etched holes in the pin junction. Here we present the BW and QE of Si PDs achievable with micro/nanoholes based on a combination of empirical evidence and device modeling. Higher than 50 Gb/s data rate with greater than 40% QE at 850 nm is conceivable in transceivers designed with such Si PDs that are integrated with photon trapping micro and nanostructures. By monolithic integration with CMOS/BiCMOS integrated circuits such as transimpedance amplifiers, equalizers, limiting amplifiers and other application specific integrated circuits (ASIC), the data rate can be increased to more than 50 Gb/s.

  17. Nano-multiplication region avalanche photodiodes and arrays

    Science.gov (United States)

    Zheng, Xinyu (Inventor); Pain, Bedabrata (Inventor); Cunningham, Thomas J. (Inventor)

    2011-01-01

    An avalanche photodiode with a nano-scale reach-through structure comprising n-doped and p-doped regions, formed on a silicon island on an insulator, so that the avalanche photodiode may be electrically isolated from other circuitry on other silicon islands on the same silicon chip as the avalanche photodiode. For some embodiments, multiplied holes generated by an avalanche reduces the electric field in the depletion region of the n-doped and p-doped regions to bring about self-quenching of the avalanche photodiode. Other embodiments are described and claimed.

  18. Silicon-Based Integration of Groups III, IV, V Chemical Vapor Depositions in High-Quality Photodiodes

    NARCIS (Netherlands)

    Sammak, A.

    2012-01-01

    Heterogeneous integration of III-V semiconductors with silicon (Si) technology is an interesting approach to utilize the advantages of both high-speed photonic and electronic properties. The work presented in this thesis is initiated by this major goal of merging III-V semiconductor technology with

  19. Conception and modelling of photo-detection pixels. PIN photodiodes conceived in amorphous silicon for particles detection

    International Nuclear Information System (INIS)

    Negru, R.

    2008-06-01

    The research done has revealed that the a-Si:H is a material ideally suited for the detection of particles, while being resistant to radiation. It also has a low manufacturing cost, is compatible with existing technology and can be deposited over large areas. Thus, despite the low local mobility of charges (30 cm 2 /V/s), a-Si:H is a material of particular interest for manufacturing high-energy particle detection pixels. As a consequence of this, we have studied the feasibility of an experimental pixel stacked structure based on a-Si:H as a basic sensor element for an electromagnetic calorimeter. The structure of such a pixel consists of different components. First, a silicon PIN diode in a-Si:H is fabricated, followed by a bias resistor and a decoupling capacitor. Before such a structure is made and in order to optimize its design, it is essential to have an efficient behavioural model of the various components. Thus, our primary goal was to develop a two-dimensional physical model of the PIN diode using the SILVACO finite element calculation software. This a-Si:H PIN diode two-dimensional physical model allowed us to study the problem of crosstalk between pixels in a matrix structure of detectors. In particular, we concentrated on the leakage current and the current generated in the volume between neighbouring pixels. The successful implementation of this model in SPICE ensures its usefulness in other professional simulators and especially its integration into a complete electronic structure (PIN diode, bias resistor, decoupling capacity and low noise amplifier). Thanks to these modelling tools, we were able to simulate PIN diode structures in a-Si:H with different thicknesses and different dimensions. These simulations have allowed us to predict that the thicker structures are relevant to the design of the pixel detectors for high energy physics. Applications in astronomy, medical imaging and the analysis of the failure of silicon integrated circuits, can also

  20. Inexpensive Pyranometer

    Science.gov (United States)

    Yanow, Gilbert

    1996-01-01

    Pyranometer generates output potential of about 300 mV in maximum sunlight. Designed to monitor insolation at accuracy within 5 percent of accuracy of instruments ordinarily used for this purpose. Suitable for use in school laboratories and perhaps in commercial facilities where expense of more precise instrument not justified. Slightly more complex pyranometer intended primarily for use in agricultural setting described in "Inexpensive Meter For Total Solar Radiation" (NPO-16741).

  1. Low-energy X-ray and gamma spectrometry using silicon photodiodes; Espectrometria de raios X e gama de baixa energia utilizando fotodiodos de silicio

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Iran Jose Oliveira da

    2000-08-01

    The use of semiconductor detectors for radiation detection has increased in recent years due to advantages they present in comparison to other types of detectors. As the working principle of commercially available photodiodes is similar to the semiconductor detector, this study was carried out to evaluate the use of Si photodiodes for low energy x-ray and gamma spectrometry. The photodiodes investigated were SFH-205, SFH-206, BPW-34 and XRA-50 which have the following characteristics: active area of 0,07 cm{sup 2} and 0,25 cm{sup 2}, thickness of the depletion ranging from 100 to 200 {mu}m and junction capacitance of 72 pF. The photodiode was polarized with a reverse bias and connected to a charge sensitive pre-amplifier, followed by a amplifier and multichannel pulse analyzer. Standard radiation source used in this experiment were {sup 241} Am, {sup 109} Cd, {sup 57} Co and {sup 133} Ba. The X-ray fluorescence of lead and silver were also measured through K- and L-lines. All the measurements were made with the photodiodes at room temperature.The results show that the responses of the photodiodes very linear by the x-ray energy and that the energy resolution in FWHM varied between 1.9 keV and 4.4 keV for peaks corresponding to 11.9 keV to 59 keV. The BPW-34 showed the best energy resolution and the lower dark current. The full-energy peak efficiency was also determined and it was observed that the peak efficiency decreases rapidly above 50 keV. The resolution and efficiency are similar to the values obtained with other semiconductor detectors, evidencing that the photodiodes used in that study can be used as a good performance detector for low energy X-ray and gamma spectrometry. (author)

  2. Microtextured Silicon Surfaces for Detectors, Sensors & Photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Carey, JE; Mazur, E

    2005-05-19

    With support from this award we studied a novel silicon microtexturing process and its application in silicon-based infrared photodetectors. By irradiating the surface of a silicon wafer with intense femtosecond laser pulses in the presence of certain gases or liquids, the originally shiny, flat surface is transformed into a dark array of microstructures. The resulting microtextured surface has near-unity absorption from near-ultraviolet to infrared wavelengths well below the band gap. The high, broad absorption of microtextured silicon could enable the production of silicon-based photodiodes for use as inexpensive, room-temperature multi-spectral photodetectors. Such detectors would find use in numerous applications including environmental sensors, solar energy, and infrared imaging. The goals of this study were to learn about microtextured surfaces and then develop and test prototype silicon detectors for the visible and infrared. We were extremely successful in achieving our goals. During the first two years of this award, we learned a great deal about how microtextured surfaces form and what leads to their remarkable optical properties. We used this knowledge to build prototype detectors with high sensitivity in both the visible and in the near-infrared. We obtained room-temperature responsivities as high as 100 A/W at 1064 nm, two orders of magnitude higher than standard silicon photodiodes. For wavelengths below the band gap, we obtained responsivities as high as 50 mA/W at 1330 nm and 35 mA/W at 1550 nm, close to the responsivity of InGaAs photodiodes and five orders of magnitude higher than silicon devices in this wavelength region.

  3. Actinide oxide photodiode and nuclear battery

    Energy Technology Data Exchange (ETDEWEB)

    Sykora, Milan; Usov, Igor

    2017-12-05

    Photodiodes and nuclear batteries may utilize actinide oxides, such a uranium oxide. An actinide oxide photodiode may include a first actinide oxide layer and a second actinide oxide layer deposited on the first actinide oxide layer. The first actinide oxide layer may be n-doped or p-doped. The second actinide oxide layer may be p-doped when the first actinide oxide layer is n-doped, and the second actinide oxide layer may be n-doped when the first actinide oxide layer is p-doped. The first actinide oxide layer and the second actinide oxide layer may form a p/n junction therebetween. Photodiodes including actinide oxides are better light absorbers, can be used in thinner films, and are more thermally stable than silicon, germanium, and gallium arsenide.

  4. Gallium-based avalanche photodiode optical crosstalk

    International Nuclear Information System (INIS)

    Blazej, Josef; Prochazka, Ivan; Hamal, Karel; Sopko, Bruno; Chren, Dominik

    2006-01-01

    Solid-state single photon detectors based on avalanche photodiode are getting more attention in various areas of applied physics: optical sensors, quantum key distribution, optical ranging and Lidar, time-resolved spectroscopy, X-ray laser diagnostics, and turbid media imaging. Avalanche photodiodes specifically designed for single photon counting semiconductor avalanche structures have been developed on the basis of various materials: Si, Ge, GaP, GaAsP, and InGaP/InGaAs at the Czech Technical University in Prague during the last 20 years. They have been tailored for numerous applications. Trends in demand are focused on detection array construction recently. Even extremely small arrays containing a few cells are of great importance for users. Electrical crosstalk between individual gating and quenching circuits and optical crosstalk between individual detecting cells are serious limitation for array design and performance. Optical crosstalk is caused by the parasitic light emission of the avalanche which accompanies the photon detection process. We have studied in detail the optical emission of the avalanche photon counting structure in the silicon- and gallium-based photodiodes. The timing properties and spectral distribution of the emitted light have been measured for different operating conditions to quantify optical crosstalk. We conclude that optical crosstalk is an inherent property of avalanche photodiode operated in Geiger mode. The only way to minimize optical crosstalk in avalanche photodiode array is to build active quenching circuit with minimum response time

  5. Conception and modelling of photo-detection pixels. PIN photodiodes conceived in amorphous silicon for particles detection; Conception et modelisation de pixels de photodetection: Photodiodes PIN en silicium amorphe en vue de leurs utilisations comme detecteurs de particules

    Energy Technology Data Exchange (ETDEWEB)

    Negru, R

    2008-06-15

    The research done has revealed that the a-Si:H is a material ideally suited for the detection of particles, while being resistant to radiation. It also has a low manufacturing cost, is compatible with existing technology and can be deposited over large areas. Thus, despite the low local mobility of charges (30 cm{sup 2}/V/s), a-Si:H is a material of particular interest for manufacturing high-energy particle detection pixels. As a consequence of this, we have studied the feasibility of an experimental pixel stacked structure based on a-Si:H as a basic sensor element for an electromagnetic calorimeter. The structure of such a pixel consists of different components. First, a silicon PIN diode in a-Si:H is fabricated, followed by a bias resistor and a decoupling capacitor. Before such a structure is made and in order to optimize its design, it is essential to have an efficient behavioural model of the various components. Thus, our primary goal was to develop a two-dimensional physical model of the PIN diode using the SILVACO finite element calculation software. This a-Si:H PIN diode two-dimensional physical model allowed us to study the problem of crosstalk between pixels in a matrix structure of detectors. In particular, we concentrated on the leakage current and the current generated in the volume between neighbouring pixels. The successful implementation of this model in SPICE ensures its usefulness in other professional simulators and especially its integration into a complete electronic structure (PIN diode, bias resistor, decoupling capacity and low noise amplifier). Thanks to these modelling tools, we were able to simulate PIN diode structures in a-Si:H with different thicknesses and different dimensions. These simulations have allowed us to predict that the thicker structures are relevant to the design of the pixel detectors for high energy physics. Applications in astronomy, medical imaging and the analysis of the failure of silicon integrated circuits, can

  6. The Study of Al0.29Ga0.71N-BASED Schottky Photodiodes Grown on Silicon by Plasma-Assisted Molecular Beam Epitaxy

    Science.gov (United States)

    Mohd Yusoff, M. Z.; Hassan, Z.; Chin, C. W.; Hassan, H. Abu; Abdullah, M. J.; Mohammad, N. N.; Ahmad, M. A.; Yusof, Y.

    2013-05-01

    In this paper, the growth and characterization of epitaxial Al0.29Ga0.71N grown on Si(111) by RF-plasma assisted molecular beam epitaxy (MBE) are described. The Al mole fraction was derived from the HR-XRD symmetric rocking curve (RC) ω/2θ scans of (0002) plane as x = 0.29. PL spectrum of sample has shown sharp and intense band edge emission of GaN without the existence of yellow emission band, showing that it is comparable in crystal quality of the sample when compared with previous reports. From the Raman measurement of as-grown Al0.29Ga0.71N layer on GaN/AlN/Si sample. We found that the dominant E2 (high) phonon mode of GaN appears at 572.7 cm-1. The E2 (high) mode of AlN appears at 656.7 cm-1 and deviates from the standard value of 655 cm-1 for unstrained AlN. Finally, AlGaN Schottky photodiode have been fabricated and analyzed by mean of electrical characterization, using current-voltage (I-V) measurement to evaluate the performance of this device.

  7. Electronic response of a photodiode coupled to a boron thin film

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Priscila; Costa, Fabio E.; Raele, Marcus P.; Zahn, Guilherme S.; Geraldo, Bianca; Vieira Junior, Nilson D.; Samad, Ricardo E.; Genezini, Frederico A., E-mail: priscila3.costa@usp.br, E-mail: fredzini@ipen.br [Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil)

    2017-07-01

    A portable thermal neutron detector is proposed in this work using a silicon photodiode coupled to a boron thin film. The aim of this work was to verify the effect in the electronic response of this specific photodiode due to boron deposition, since the direct deposition of boron in the semiconductor surface could affect its electrical properties specifically the p-type layer that affects directly the depletion region of the semiconductor reducing the neutron detector efficiency count. Three boron depositions with different thickness were performed in the photodiode (S3590-09) surface by pulsed laser deposition and the photodiode was characterized, before and after the deposition process, using a radioactive americium source. Energy spectra were used to verify the electronic response of the photodiode, due to the fact that it is possible to relate it to the photopeak pulse height and resolution. Spectra from the photodiode without and with boron film deposition were compared and a standard photodiode (S3590-04) that had the electronic signal conserved was used as reference to the pulse height for electronics adjustments. The photopeak energy resolution for the photodiode without boron layer was 10.26%. For the photodiode with boron deposition at different thicknesses, the resolution was: 7.64 % (0.14 μm), 7.30 % (0.44 μm) and 6.80 % (0.63 μm). From these results it is possible to evaluate that there was not any degradation in the silicon photodiode. (author)

  8. Reliability studies on Si PIN photodiodes under Co-60 gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Prabhakara Rao, Y. P. [Integrated Circuits Division, Bharat Electronics Limited, Bangalore, Karnataka-560013 (India) and Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore, Karnataka-570006 (India); Praveen, K. C.; Gnana Prakash, A. P. [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore, Karnataka-570006 (India); Rani, Y. Rejeena [Integrated Circuits Division, Bharat Electronics Limited, Bangalore, Karnataka-560013 (India)

    2013-02-05

    Silicon PIN photodiodes were fabricated with 250 nm SiO{sub 2} antireflective coating (ARC). The changes in the electrical characteristics, capacitance-voltage characteristics and spectral response after gamma irradiation are systematically studied to estimate the radiation tolerance up to 10 Mrad. The different characteristics studied in this investigation demonstrate that Si PIN photodiodes are suitable for high radiation environment.

  9. I-V and C-V Characterization of a High-Responsivity Graphene/Silicon Photodiode with Embedded MOS Capacitor.

    Science.gov (United States)

    Luongo, Giuseppe; Giubileo, Filippo; Genovese, Luca; Iemmo, Laura; Martucciello, Nadia; Di Bartolomeo, Antonio

    2017-06-27

    We study the effect of temperature and light on the I-V and C-V characteristics of a graphene/silicon Schottky diode. The device exhibits a reverse-bias photocurrent exceeding the forward current and achieves a photoresponsivity as high as 2.5 A / W . We show that the enhanced photocurrent is due to photo-generated carriers injected in the graphene/Si junction from the parasitic graphene/SiO₂/Si capacitor connected in parallel to the diode. The same mechanism can occur with thermally generated carriers, which contribute to the high leakage current often observed in graphene/Si junctions.

  10. I-V and C-V Characterization of a High-Responsivity Graphene/Silicon Photodiode with Embedded MOS Capacitor

    OpenAIRE

    Luongo, Giuseppe; Giubileo, Filippo; Genovese, Luca; Iemmo, Laura; Martucciello, Nadia; Di Bartolomeo, Antonio

    2017-01-01

    We study the effect of temperature and light on the I-V and C-V characteristics of a graphene/silicon Schottky diode. The device exhibits a reverse-bias photocurrent exceeding the forward current and achieves a photoresponsivity as high as 2.5 ? A / W . We show that the enhanced photocurrent is due to photo-generated carriers injected in the graphene/Si junction from the parasitic graphene/SiO2/Si capacitor connected in parallel to the diode. The same mechanism can occur with thermally genera...

  11. Panoramic irradiator dose mapping with pin photodiodes

    International Nuclear Information System (INIS)

    Ferreira, Danilo Cardenuto; Napolitano, Celia Marina; Bueno, Carmen Cecilia

    2011-01-01

    In this work we study the possibility of using commercial silicon PIN photodiodes (Siemens, SFH 00206) for dose mapping in the Panoramic Irradiator facility at IPEN-CNEN/SP. The chosen photodiode, that is encased in 1.2 mm thickness polymer layer, displays promising dosimetric characteristics such as small size (sensitive area of 7.00 mm 2 ), high sensitivity and low dark current (≅ 300 pA, at 0 V) together with low-cost and wide availability. The Panoramic facility is an irradiator Type II with absorbed dose certificated by International Dose Assurance Service (IDAS) offered by the International Agency Energy Atomic (IAEA). The charge registered by the diode as a function of the absorbed dose was in excellent agreement with that one calibrated by IDAS. Besides this, the easy handling and fast response of the SFH00206 diode compared to Fricke chemical dosimeters encouraged us to perform dose mapping around the source. (author)

  12. A Ring-shaped photodiode designed for use in a reflectance pulse oximetry sensor in wireless health monitoring applications

    DEFF Research Database (Denmark)

    Duun, Sune; Haahr, Rasmus Grønbek; Birkelund, Karen

    2010-01-01

    We report a photodiode for use in a reflectance pulse oximeter for use in autonomous and low-power homecare applications. The novelty of the reflectance pulse oximeter is a large ring shaped backside silicon pn photodiode. The ring-shaped photodiode gives optimal gathering of light and thereby...... enable very low light-emitting diode (LED) driving currents for the pulse oximeter. The photodiode also have a two layer SiO2/SiN interference filter yielding 98% transmission at the measuring wavelengths, 660 nm and 940 nm, and suppressing other wavelengths down to 50% transmission. The photodiode has...

  13. Development of a gamma dosimeter using a photodiode

    International Nuclear Information System (INIS)

    Melo, F.A. de.

    1988-05-01

    In the last years, the application of semiconductor detectors in radiation spectroscopy and dosimetry has increased. Silicon diodes have found utility in radiation dosimetry principally because a diode produces a current approximately 18000 times larger than of an ionization chamber of an equal sensitive volume. As the characteristics of the semiconductor detectors are the same as the common photodiode, a gamma dosimeter using this type of electronic component was developed. The photodiode SFH206 operating in photovoltaic mode was used. An electrometric unit was constructed to measure the current generated in this detector. The results obtained showed: the response of the photodiode was linear with the dose and that variation of 40 degrees in the incidence angle of the radiation caused a variation of 5% in the dose determination; the response reproducibility of the photodiode was studied, and the results showed that the variation coefficient is smaller than 0,02%; the small dimension of the silicon photodiode recommend its use as a gamma dosimeter for medical applications. (author). 19 refs, 32 figs, 1 tab

  14. Investigation of avalanche photodiodes

    Energy Technology Data Exchange (ETDEWEB)

    Si Mohand, D.; Benhammou, Y.; Depasse, P.; Goyot, M.; Ille, B.; Linard, E.; Martin, F.; Musienko, Y.

    1996-06-01

    Some characteristics and performances of a set of nine Hamamatsu avalanche photodiodes have been investigated. These APDs have equipped a small 3x3 PbWO{sub 4} crystal matrix in X3 beam during the summer of 1995. This note summarizes the main results of this work. An electromagnetic calorimeter with a high resolution is necessary to search for the Higgs if it has a mass between 80 and 160 GeV. A PbWO{sub 4} crystal option has been chosen by the CMS collaboration to achieve this task. The light is collected and converted into an electric charge by an Avalanche Photodiode (APD) followed by a fast preamplifier. The advantage of the APDs is that they are not sensitive to the strong magnetic field when compared to photomultipliers and they are a small nuclear counter effect when compared to PIN diodes. In this study, we have tested nine low capacitance Hamamatsu APDs (S5345) received in spring, 1995 with an area of 0.2 cm{sup 2}. We have measured the capacitance and dark current for each APD. The gain measurements have also been done with gamma sources, continuous and pulsed light. The gain sensitivity versus bias and temperature have also been investigated succinctly. (author). 8 refs., 16 figs., 1 tab.

  15. Investigation of avalanche photodiodes

    International Nuclear Information System (INIS)

    Si Mohand, D.; Benhammou, Y.; Depasse, P.; Goyot, M.; Ille, B.; Linard, E.; Martin, F.; Musienko, Y.

    1996-06-01

    Some characteristics and performances of a set of nine Hamamatsu avalanche photodiodes have been investigated. These APDs have equipped a small 3x3 PbWO 4 crystal matrix in X3 beam during the summer of 1995. This note summarizes the main results of this work. An electromagnetic calorimeter with a high resolution is necessary to search for the Higgs if it has a mass between 80 and 160 GeV. A PbWO 4 crystal option has been chosen by the CMS collaboration to achieve this task. The light is collected and converted into an electric charge by an Avalanche Photodiode (APD) followed by a fast preamplifier. The advantage of the APDs is that they are not sensitive to the strong magnetic field when compared to photomultipliers and they are a small nuclear counter effect when compared to PIN diodes. In this study, we have tested nine low capacitance Hamamatsu APDs (S5345) received in spring, 1995 with an area of 0.2 cm 2 . We have measured the capacitance and dark current for each APD. The gain measurements have also been done with gamma sources, continuous and pulsed light. The gain sensitivity versus bias and temperature have also been investigated succinctly. (author). 8 refs., 16 figs., 1 tab

  16. Radon measurements with a PIN photodiode

    International Nuclear Information System (INIS)

    Martin-Martin, A.; Gutierrez-Villanueva, J.L.; Munoz, J.M.; Garcia-Talavera, M.; Adamiec, G.; Iniguez, M.P.

    2006-01-01

    Silicon photodiodes are well suited to detect alphas coming from different sources as neutron reactions or radon daughters. In this work a radon in air detecting device, using an 18x18 mm silicon PIN photodiode is studied. The ionized airborne decay products formed during radon diffusion were focused by an accelerating high voltage to the PIN surface. Several conducting rings were disposed inside a cylindrical PVC vessel in such a way that they reproduced the electric field created by a punctual charge located behind PIN position. Alpha spectra coming from the neutral and ionized species deposited on the PIN surface, dominated by 218 Po and 214 Po progeny peaks, were recorded for varying conditions. Those include radon concentration from a Pylon source, high voltage (thousands of volts) and PIN inverse bias voltage. Different parameters such as temperature and humidity were also registered during data acquisition. The increase in the particle collection efficiency with respect to zero electric field was compared with the corresponding to a parallel plates configuration. A discussion is made in terms of the most appropriate voltages for different radon concentrations

  17. 75 MeV boron ion irradiation studies on Si PIN photodiodes

    Energy Technology Data Exchange (ETDEWEB)

    Prabhakara Rao, Y.P.; Praveen, K.C. [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore 570006 (India); Rejeena Rani, Y. [Integrated Circuits Division, Bharat Electronics Limited, Bangalore 560013, Karnataka (India); Tripathi, Ambuj [Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India); Gnana Prakash, A.P., E-mail: gnanap@hotmail.com [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore 570006 (India)

    2013-12-01

    The highly sensitive silicon PIN photodiodes were fabricated to use in radiation environments. The Si PIN photodiodes are coated with 150 nm silicon dioxide (SiO{sub 2}) as anti-reflective (AR) coating. The presence of AR coating on the performance of irradiated PIN photodiodes is studied up to a total dose of 10 Mrad. The effects of 75 MeV boron (B{sup 5+}) ions and {sup 60}Co gamma radiation on the I–V, C–V and spectral responses of PIN photodiodes were studied systematically to understand the radiation tolerance of the devices. The 75 MeV B{sup 5+} irradiation results are compared with {sup 60}Co gamma irradiated results in the same dose range for 1 mm × 1 mm and 10 mm × 10 mm active area PIN photodiodes. The irradiation results show that the ion irradiated PIN photodiodes show more degradation when compared {sup 60}Co gamma irradiated devices. The irradiation results are presented in this paper and the possible mechanism behind the degradation of photodiodes is also discussed in the paper.

  18. High speed photodiodes in standard nanometer scale CMOS technology: a comparative study.

    Science.gov (United States)

    Nakhkoob, Behrooz; Ray, Sagar; Hella, Mona M

    2012-05-07

    This paper compares various techniques for improving the frequency response of silicon photodiodes fabricated in mainstream CMOS technology for fully integrated optical receivers. The three presented photodiodes, Spatially Modulated Light detectors, Double, and Interrupted P-Finger photodiodes, aim at reducing the low speed diffusive component of the photo generated current. For the first photodiode, Spatially Modulated Light (SML) detectors, the low speed current component is canceled out by converting it to a common mode current driving a differential transimpedance amplifier. The Double Photodiode (DP) uses two depletion regions to increase the fast drift component, while the Interrupted-P Finger Photodiode (IPFPD) redirects the low speed component towards a different contact from the main fast terminal of the photodiode. Extensive device simulations using 130 nm CMOS technology-parameters are presented to compare their performance using the same technological platform. Finally a new type of photodiode that uses triple well CMOS technology is introduced that can achieve a bandwidth of roughly 10 GHz without any process modification or high reverse bias voltages that would jeopardize the photodetector and subsequent transimpedance amplifier reliability.

  19. Evaluation of gamma dose effect on PIN photodiode using analytical model

    Science.gov (United States)

    Jafari, H.; Feghhi, S. A. H.; Boorboor, S.

    2018-03-01

    The PIN silicon photodiodes are widely used in the applications which may be found in radiation environment such as space mission, medical imaging and non-destructive testing. Radiation-induced damage in these devices causes to degrade the photodiode parameters. In this work, we have used new approach to evaluate gamma dose effects on a commercial PIN photodiode (BPX65) based on an analytical model. In this approach, the NIEL parameter has been calculated for gamma rays from a 60Co source by GEANT4. The radiation damage mechanisms have been considered by solving numerically the Poisson and continuity equations with the appropriate boundary conditions, parameters and physical models. Defects caused by radiation in silicon have been formulated in terms of the damage coefficient for the minority carriers' lifetime. The gamma induced degradation parameters of the silicon PIN photodiode have been analyzed in detail and the results were compared with experimental measurements and as well as the results of ATLAS semiconductor simulator to verify and parameterize the analytical model calculations. The results showed reasonable agreement between them for BPX65 silicon photodiode irradiated by 60Co gamma source at total doses up to 5 kGy under different reverse voltages.

  20. Measurement of X-ray spectra by PIN photodiode: comparative study

    International Nuclear Information System (INIS)

    Costa, Paulo R.; Furquim, Tania A.C.; Herdade, Silvio B.

    1996-01-01

    Two different approaches for the evaluation of diagnostic X-ray spectra are presented : one based on a semiempirical model and other based on measurements using a silicon PIN photodiode. Measured and calculated values using typical kVp and filter combinations are compared

  1. Geiger-Mode Avalanche Photodiode Arrays Integrated to All-Digital CMOS Circuits.

    Science.gov (United States)

    Aull, Brian

    2016-04-08

    This article reviews MIT Lincoln Laboratory's work over the past 20 years to develop photon-sensitive image sensors based on arrays of silicon Geiger-mode avalanche photodiodes. Integration of these detectors to all-digital CMOS readout circuits enable exquisitely sensitive solid-state imagers for lidar, wavefront sensing, and passive imaging.

  2. Performances of photodiode detectors for top and bottom counting detectors of ISS-CREAM experiment

    Energy Technology Data Exchange (ETDEWEB)

    Hyun, H.J. [Kyungpook National University, Daegu 702-701 (Korea, Republic of); Anderson, T. [Pennsylvania State University, University Park, PA 16802 (United States); Angelaszek, D. [University of Maryland, College Park, MD 20740 (United States); Baek, S.J. [Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Copley, M. [University of Maryland, College Park, MD 20740 (United States); Coutu, S. [Pennsylvania State University, University Park, PA 16802 (United States); Han, J.H.; Huh, H.G. [University of Maryland, College Park, MD 20740 (United States); Hwang, Y.S. [Kyungpook National University, Daegu 702-701 (Korea, Republic of); Im, S. [Pennsylvania State University, University Park, PA 16802 (United States); Jeon, H.B.; Kah, D.H.; Kang, K.H.; Kim, H.J. [Kyungpook National University, Daegu 702-701 (Korea, Republic of); Kim, K.C.; Kwashnak, K. [University of Maryland, College Park, MD 20740 (United States); Lee, J. [Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Lee, M.H. [University of Maryland, College Park, MD 20740 (United States); Link, J.T. [NASA GSFC, Greenbelt, MD 20771 (United States); CRESST(USRA), Columbia, MD 21044 (United States); Lutz, L. [University of Maryland, College Park, MD 20740 (United States); and others

    2015-07-01

    The Cosmic Ray Energetics and Mass (CREAM) experiment at the International Space Station (ISS) aims to elucidate the source and acceleration mechanisms of high-energy cosmic rays by measuring the energy spectra from protons to iron. The instrument is planned for launch in 2015 at the ISS, and it comprises a silicon charge detector, a carbon target, top and bottom counting detectors, a calorimeter, and a boronated scintillator detector. The top and bottom counting detectors are developed for separating the electrons from the protons, and each of them comprises a plastic scintillator and a 20×20 silicon photodiode array. Each photodiode is 2.3 cm×2.3 cm in size and exhibits good electrical characteristics. The leakage current is measured to be less than 20 nA/cm{sup 2} at an operating voltage. The signal-to-noise ratio is measured to be better than 70 using commercial electronics, and the radiation hardness is tested using a proton beam. A signal from the photodiode is amplified by VLSI (very-large-scale integration) charge amp/hold circuits, the VA-TA viking chip. Environmental tests are performed using whole assembled photodiode detectors of a flight version. Herein, we present the characteristics of the developed photodiode along with the results of the environmental tests.

  3. Performances of photodiode detectors for top and bottom counting detectors of ISS-CREAM experiment

    International Nuclear Information System (INIS)

    Hyun, H.J.; Anderson, T.; Angelaszek, D.; Baek, S.J.; Copley, M.; Coutu, S.; Han, J.H.; Huh, H.G.; Hwang, Y.S.; Im, S.; Jeon, H.B.; Kah, D.H.; Kang, K.H.; Kim, H.J.; Kim, K.C.; Kwashnak, K.; Lee, J.; Lee, M.H.; Link, J.T.; Lutz, L.

    2015-01-01

    The Cosmic Ray Energetics and Mass (CREAM) experiment at the International Space Station (ISS) aims to elucidate the source and acceleration mechanisms of high-energy cosmic rays by measuring the energy spectra from protons to iron. The instrument is planned for launch in 2015 at the ISS, and it comprises a silicon charge detector, a carbon target, top and bottom counting detectors, a calorimeter, and a boronated scintillator detector. The top and bottom counting detectors are developed for separating the electrons from the protons, and each of them comprises a plastic scintillator and a 20×20 silicon photodiode array. Each photodiode is 2.3 cm×2.3 cm in size and exhibits good electrical characteristics. The leakage current is measured to be less than 20 nA/cm 2 at an operating voltage. The signal-to-noise ratio is measured to be better than 70 using commercial electronics, and the radiation hardness is tested using a proton beam. A signal from the photodiode is amplified by VLSI (very-large-scale integration) charge amp/hold circuits, the VA-TA viking chip. Environmental tests are performed using whole assembled photodiode detectors of a flight version. Herein, we present the characteristics of the developed photodiode along with the results of the environmental tests

  4. Study of a PIN photodiode as an ionizing radiation detector for aerospace use

    International Nuclear Information System (INIS)

    Nogueira, S.F.L.; Claro, L.H.; Santos, J.A.; Junior, J.R.; Federico, C.A.

    2017-01-01

    This work aims to study the use of the COTS PIN photodiode with an active area of 7.5 mm 2 as an ionizing radiation detector. The tests were performed with a 60 Co source and with low activity radioisotopic sources of 60 Co, 152 Eu, 137 Cs and 241 Am. The results were obtained by analyzing the current response generated by the photodiodes as a function of an attenuated dose rate in silicon in the range of 0.55 to 11.54 Gy / h

  5. Ultra compact 45 GHz CMOS compatible Germanium waveguide photodiode with low dark current.

    Science.gov (United States)

    DeRose, Christopher T; Trotter, Douglas C; Zortman, William A; Starbuck, Andrew L; Fisher, Moz; Watts, Michael R; Davids, Paul S

    2011-12-05

    We present a compact 1.3 × 4 μm2 Germanium waveguide photodiode, integrated in a CMOS compatible silicon photonics process flow. This photodiode has a best-in-class 3 dB cutoff frequency of 45 GHz, responsivity of 0.8 A/W and dark current of 3 nA. The low intrinsic capacitance of this device may enable the elimination of transimpedance amplifiers in future optical data communication receivers, creating ultra low power consumption optical communications.

  6. Avalanche photodiodes for ISABELLE detectors

    International Nuclear Information System (INIS)

    Strand, R.C.

    1979-01-01

    At ISABELLE some requirements for detecting bursts of photons are not met by standard photomultiplier tubes. The characteristics of immunity to magnetic fields, small size (few mm), low power consumption (approx. 100 mW), insensitivity to optical overloads, and wide dynamic range (approx. 60 dB) are achieved with difficulty, if at all, with PMTs. These are characteristics of the solid state avalanche photodiode (APD), the preferred detector for light-wave communications. Successful field tests with APD detectors stimulated the design of standard optical-fiber communication systems to replace wire carriers by the early 1980's. In other characteristics, i.e., counting rate, pulse-height resolution, effective quantum efficiency, detection efficiency, and reliability, bare APDs are equivalent to standard PMTs. APDs with currently available amplifiers cannot resolve single photoelectrons but they could provide reasonable detection efficiencies and pulse-height resolution for packets of approx. > 100 photons. Commercially available APDs can cost up to 100 times as much as PMTs per active area, but they are potentially much cheaper. Six topics are discussed: (1) detectors for light-wave communication and detectors for particles, (2) avalanche photodiodes, (3) commercially available APDs, (4) dynamic response of PMTs and bare APDs, (5) photon counting with cold APDs, and (6) conclusions and recommendations

  7. Substitution of photomultiplier tubes by photodiodes

    International Nuclear Information System (INIS)

    Teixeira, D.L.

    1990-04-01

    The application of Si semiconductors, either of the conventional or the avalanche type, as light amplifiers in radiation detection, has been studied aiming the substitution of photomultiplier (PM) tubes by photodiodes. The objective of this work is to compare the response of photodiodes and PM tubes when coupled to scintillation crystals. A Hamamatsu Si photodiode, model S 1337-66 B Q, was coupled to a Harshaw NaI (TI) scintillation crystal of window diameter equal to 25,4 mm. Its performance was evaluated by specially designed associated electronics, compatible with the photodiode characteristics. X-ray beams from 30 to 111 KeV were used to determine the response and the repeatability of the scintillator-photodiode and the scintillator-PM tube systems. The repeatability was found to be within 0,27% for the photodiode and 0,57% for the PM tube. This work confirmed that photodiodes can be used as light amplifiers, provided their characteristics, such as light spectrum response, are considered. It also shows that further studies are necessary in order to identify the applications in radiation detection where PM tubes might be replaced by photodiodes. (author)

  8. The photodiodes response in beta dosimetry

    International Nuclear Information System (INIS)

    Khoury, Helen; Amaral, Ademir; Hazin, Clovis; Melo, Francisco

    1996-01-01

    The response of the photodiodes BPY-12, BPW-34 and SFH-206 is tested for use as beta dosimeters. The results obtained show a dose-response relationships as well as less than 1% of coefficient of variation for the reproducibility of their responses. The photodiode BPY-12 has presented a better response in comparison with the others

  9. Gamma ray spectroscopy and timing using LSO and PIN photodiodes

    International Nuclear Information System (INIS)

    Moses, W.W.; Derenzo, S.E.; Melcher, C.L.; Manente, R.A.

    1994-11-01

    The high density, high light output, and short decay time of LSO (lutetium orthosilicate, Lu 2 SiO 5 :Ce) make it an attractive scintillator for gamma ray spectroscopy. The low cost, small size, high quantum efficiency, and ruggedness of silicon photodiodes make them attractive photodetectors for this same application, although their high noise (Compared to a photomultiplier tube) reduces their appeal. In this work the authors measure the gamma ray energy resolution, timing accuracy, and conversion factor from gamma energy to number of electron-hole pairs produced with a 3 x 3 x 22 mm 3 LSO scintillator crystal read out with a 3 x 3 mm 2 silicon PIN photodiode. When the detector is excited with 511 keV photons, a photopeak centered at 1,940 e - with 149 keV fwhm is observed and a timing signal with 35 ns fwhm jitter is produced. When the detector is excited with 1,275 keV photons, a photopeak centered at 4,910 e - with 149 keV fwhm is observed and a timing signal with 25 ns fwhm jitter is produced. While these performance measures are inferior to those obtained with photomultiplier tubes, they are acceptable for some applications

  10. Continued Development Of An Inexpensive Simulator Based CT Scanner For Radiation Therapy Treatment Planning

    Science.gov (United States)

    Peschmann, K. R.; Parker, D. L.; Smith, V.

    1982-11-01

    An abundant number of different CT scanner models has been developed in the past ten years, meeting increasing standards of performance. From the beginning they remained a comparatively expensive piece of equipment. This is due not only to their technical complexity but is also due to the difficulties involved in assessing "true" specifications (avoiding "overde-sign"). Our aim has been to provide, for Radiation Therapy Treatment Planning, a low cost CT scanner system featuring large freedom in patient positioning. We have taken advantage of the concurrent tremendously increased amount of knowledge and experience in the technical area of CT1 . By way of extensive computer simulations we gained confidence that an inexpensive C-arm simulator gantry and a simple one phase-two pulse generator in connection with a standard x-ray tube could be used, without sacrificing image quality. These components have been complemented by a commercial high precision shaft encoder, a simple and effective fan beam collimator, a high precision, high efficiency, luminescence crystal-silicon photodiode detector with 256 channels, low noise electronic preamplifier and sampling filter stages, a simplified data aquisition system furnished by Toshiba/ Analogic and an LSI 11/23 microcomputer plus data storage disk as well as various smaller interfaces linking the electrical components. The quality of CT scan pictures of phantoms,performed by the end of last year confirmed that this simple approach is working well. As a next step we intend to upgrade this system with an array processor in order to shorten recon-struction time to one minute per slice. We estimate that the system including this processor could be manufactured for a selling price of $210,000.

  11. Development of an X-ray detector using photodiodes

    International Nuclear Information System (INIS)

    Gonzalez G, J.; Azorin V, J. C.; Sosa A, M. A.; Ceron, P.

    2016-10-01

    Currently the radiation detectors for medical applications are very high value in the market and are difficult to access as training material. In the Sciences and Engineering Division of the Guanajuato University (Mexico) investigations are carried out related to ionizing radiations, especially with X-rays. To overcome the lack of materials has had to resort to borrowing equipment from other institutions, so its use and availability are intermittent. For these reasons is proposed to design and implement an X-ray detector for the use of the work group and the University. This work aims to build an X-ray semiconductor detector using inexpensive and affordable materials, is also proposed the use of a photodiode sensor and an Arduino analog-digital card and a LCD display showing the data. (Author)

  12. High performance waveguide-coupled Ge-on-Si linear mode avalanche photodiodes.

    Science.gov (United States)

    Martinez, Nicholas J D; Derose, Christopher T; Brock, Reinhard W; Starbuck, Andrew L; Pomerene, Andrew T; Lentine, Anthony L; Trotter, Douglas C; Davids, Paul S

    2016-08-22

    We present experimental results for a selective epitaxially grown Ge-on-Si separate absorption and charge multiplication (SACM) integrated waveguide coupled avalanche photodiode (APD) compatible with our silicon photonics platform. Epitaxially grown Ge-on-Si waveguide-coupled linear mode avalanche photodiodes with varying lateral multiplication regions and different charge implant dimensions are fabricated and their illuminated device characteristics and high-speed performance is measured. We report a record gain-bandwidth product of 432 GHz for our highest performing waveguide-coupled avalanche photodiode operating at 1510nm. Bit error rate measurements show operation with BER-12, in the range from -18.3 dBm to -12 dBm received optical power into a 50 Ω load and open eye diagrams with 13 Gbps pseudo-random data at 1550 nm.

  13. Photodiodes based on fullerene semiconductor

    International Nuclear Information System (INIS)

    Voz, C.; Puigdollers, J.; Cheylan, S.; Fonrodona, M.; Stella, M.; Andreu, J.; Alcubilla, R.

    2007-01-01

    Fullerene thin films have been deposited by thermal evaporation on glass substrates at room temperature. A comprehensive optical characterization was performed, including low-level optical absorption measured by photothermal deflection spectroscopy. The optical absorption spectrum reveals a direct bandgap of 2.3 eV and absorption bands at 2.8 and 3.6 eV, which are related to the creation of charge-transfer excitons. Various photodiodes on indium-tin-oxide coated glass substrates were also fabricated, using different metallic contacts in order to compare their respective electrical characteristics. The influence of a poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) buffer layer between the indium-tin-oxide electrode and the fullerene semiconductor is also demonstrated. These results are discussed in terms of the workfunction for each electrode. Finally, the behaviour of the external quantum efficiency is analyzed for the whole wavelength spectrum

  14. The Physics Show--Inexpensively.

    Science.gov (United States)

    Hultsch, Roland A.

    1982-01-01

    Describes five physics demonstrations using inexpensive and easily obtainable materials. Demonstrations include: (1) sinking ice cubes and diffusion; (2) returnable can; (3) persistent currents in a liquid; (4) light scattering by milk particles; and (5) rotation of a plane of polarization. (JN)

  15. High-End Silicon PDICs

    Directory of Open Access Journals (Sweden)

    H. Zimmermann

    2008-05-01

    Full Text Available An overview on integrated silicon photodiodes and photodiode integrated circuits (PDICs or optoelectronic integrated circuits (OEICs for optical storage systems (OSS and fiber receivers is given. It is demonstrated, that by using low-cost silicon technologies high-performance OEICs being true competitors for some III/V-semiconductor OEICs can be realized. OSS-OEICs with bandwidths of up to 380 MHz and fiber receivers with maximum data rates of up to 11 Gbps are described. Low-cost data comm receivers for plastic optical fibers (POF as well as new circuit concepts for OEICs and highly parallel optical receivers are described also in the following.

  16. Photodiodes utilization as ionizing radiation detectors

    International Nuclear Information System (INIS)

    Khoury, H.J.; Melo, F.A. de

    1987-01-01

    The response of photodiodes to α and γ radiation is studied, using for α spectrometry measures and for γ radiation dosimetry. Therefore, the response of BPY-12 photodiodes as α particle detector is first studied. The results show that the response is linear with the energy of incidence radiation, one resolution 25Kev for energy of 5,4 MeV from 241 Am. For dosimetric measures, the response of SHF-206 photodiodes, when exposed at γ radiation is studied, and the results show taht the response of this detector is linear with the dose ratio, proving its practicability in γ radiation dosimetry. (C.G.C.) [pt

  17. Compact multispectral photodiode arrays using micropatterned dichroic filters

    Science.gov (United States)

    Chandler, Eric V.; Fish, David E.

    2014-05-01

    The next generation of multispectral instruments requires significant improvements in both spectral band customization and portability to support the widespread deployment of application-specific optical sensors. The benefits of spectroscopy are well established for numerous applications including biomedical instrumentation, industrial sorting and sensing, chemical detection, and environmental monitoring. In this paper, spectroscopic (and by extension hyperspectral) and multispectral measurements are considered. The technology, tradeoffs, and application fits of each are evaluated. In the majority of applications, monitoring 4-8 targeted spectral bands of optimized wavelength and bandwidth provides the necessary spectral contrast and correlation. An innovative approach integrates precision spectral filters at the photodetector level to enable smaller sensors, simplify optical designs, and reduce device integration costs. This method supports user-defined spectral bands to create application-specific sensors in a small footprint with scalable cost efficiencies. A range of design configurations, filter options and combinations are presented together with typical applications ranging from basic multi-band detection to stringent multi-channel fluorescence measurement. An example implementation packages 8 narrowband silicon photodiodes into a 9x9mm ceramic LCC (leadless chip carrier) footprint. This package is designed for multispectral applications ranging from portable color monitors to purpose- built OEM industrial and scientific instruments. Use of an eight-channel multispectral photodiode array typically eliminates 10-20 components from a device bill-of-materials (BOM), streamlining the optical path and shrinking the footprint by 50% or more. A stepwise design approach for multispectral sensors is discussed - including spectral band definition, optical design tradeoffs and constraints, and device integration from prototype through scalable volume production

  18. Basic opto-electronics on silicon for sensor applications

    NARCIS (Netherlands)

    Joppe, J.L.; Bekman, H.H.P.Th.; de Krijger, A.J.T.; Albers, H.; Chalmers, J.; Chalmers, J.D.; Holleman, J.; Ikkink, T.J.; Ikkink, T.; van Kranenburg, H.; Zhou, M.-J.; Zhou, Ming-Jiang; Lambeck, Paul

    1994-01-01

    A general platform for integrated opto-electronic sensor systems on silicon is proposed. The system is based on a hybridly integrated semiconductor laser, ZnO optical waveguides and monolithic photodiodes and electronic circuiry.

  19. Electrical crosstalk in front-illuminated photodiode array with different guard ring designs for medical CT applications

    International Nuclear Information System (INIS)

    Ji Fan; Juntunen, Mikko; Hietanen, Iiro

    2009-01-01

    This paper presents electrical crosstalk studies on front-illuminated photodiode arrays for medical computed tomography (CT) applications. Crosstalk is an important factor to the system noise and image quality. The electrical crosstalk depends on silicon substrate properties and photodiode structures. The photodiode samples employed in this paper are planar processed on high-resistivity n-type silicon substrate, resulting in a p+/n-/n+ diode structure. Two types of guard ring structures are designed and applied to the same geometry of two-dimensional photodiode arrays. One structure is an n guard ring in the gap area between pixels, and the other structure is an additional p+ guard ring around each pixel together with the n guard ring. A 10 μm light spot with wavelength of 525 nm is used to scan across the surface of the photodiode array in the electrical crosstalk measurements. The electrical currents of two neighbor pixels are measured and the results are compared between two guard ring designs. The design with the p+ guard ring structure gives better electrical crosstalk suppression. Moreover, the measurement results show much smaller influence on surrounding pixels with the p+ guard ring structure in the case of disconnected pixel. Besides the electrical crosstalk, the light sensitivity within the gap area is also discussed between two guard ring designs.

  20. Development of a gamma dosimeter using a photodiode; Desenvolvimento de um dosimetro para radiacao gama utilizando fotodiodo

    Energy Technology Data Exchange (ETDEWEB)

    Melo, F.A. de

    1988-05-01

    In the last years, the application of semiconductor detectors in radiation spectroscopy and dosimetry has increased. Silicon diodes have found utility in radiation dosimetry principally because a diode produces a current approximately 18000 times larger than of an ionization chamber of an equal sensitive volume. As the characteristics of the semiconductor detectors are the same as the common photodiode, a gamma dosimeter using this type of electronic component was developed. The photodiode SFH206 operating in photovoltaic mode was used. An electrometric unit was constructed to measure the current generated in this detector. The results obtained showed: the response of the photodiode was linear with the dose and that variation of 40 degrees in the incidence angle of the radiation caused a variation of 5% in the dose determination; the response reproducibility of the photodiode was studied, and the results showed that the variation coefficient is smaller than 0,02%; the small dimension of the silicon photodiode recommend its use as a gamma dosimeter for medical applications. (author). 19 refs, 32 figs, 1 tab.

  1. Detection of charged particles through a photodiode: design and analysis

    International Nuclear Information System (INIS)

    Angoli, A.; Quirino, L.L.; Hernandez, V.M.; Lopez del R, H.; Mireles, F.; Davila, J.I.; Rios, C.; Pinedo, J.L.

    2006-01-01

    This project develops and construct an charge particle detector mean a pin photodiode array, design and analysis using a silicon pin Fotodiodo that generally is used to detect visible light, its good efficiency, size compact and reduced cost specifically allows to its use in the radiation monitoring and alpha particle detection. Here, so much, appears the design of the system of detection like its characterization for alpha particles where one is reported as alpha energy resolution and detection efficiency. The equipment used in the development of work consists of alpha particle a triple source composed of Am-241, Pu-239 and Cm-244 with 5,55 KBq as total activity, Maestro 32 software made by ORTEC, a multi-channel card Triumph from ORTEC and one low activity electroplated uranium sample. (Author)

  2. Light induced tunnel effect in CNT-Si photodiode

    Energy Technology Data Exchange (ETDEWEB)

    Aramo, C., E-mail: aramo@na.infn.it [INFN, Sezione di Napoli, Via Cintia 2, 80126 Napoli (Italy); Ambrosio, M. [INFN, Sezione di Napoli, Via Cintia 2, 80126 Napoli (Italy); Bonavolontà, C. [INFN, Sezione di Napoli, Via Cintia 2, 80126 Napoli (Italy); Dip. di Scienze Fisiche, Università degli Studi di Napoli “Federico II”, Via Cintia 2, 80126 Napoli (Italy); Boscardin, M. [Centro per Materiali e i Microsistemi Fondazione Bruno Kessler (FBK), Via Sommarive 18, Povo di Trento, 38123 Trento (Italy); Castrucci, P. [INFN, Sezione di Roma “Tor Vergata”, Dip. di Fisica, Università degli Studi di Roma “Tor Vergata”, Via della Ricerca Scientifica 1, 00133 Roma (Italy); Crivellari, M. [Centro per Materiali e i Microsistemi Fondazione Bruno Kessler (FBK), Via Sommarive 18, Povo di Trento, 38123 Trento (Italy); De Crescenzi, M. [INFN, Sezione di Roma “Tor Vergata”, Dip. di Fisica, Università degli Studi di Roma “Tor Vergata”, Via della Ricerca Scientifica 1, 00133 Roma (Italy); De Lisio, C. [INFN, Sezione di Napoli, Via Cintia 2, 80126 Napoli (Italy); Dip. di Scienze Fisiche, Università degli Studi di Napoli “Federico II”, Via Cintia 2, 80126 Napoli (Italy); Fiandrini, E. [INFN, Sezione di Perugia, Dip. di Fisica, Università degli Studi di Perugia, Piazza Università 1, 06100 Perugia (Italy); and others

    2016-07-11

    Negative differential resistance (NDR), for which the current is a decreasing function of the voltage, has been observed in the current–voltage curves of several types of structures. We measured tunnelling current and NDR by illuminating large area heterojunction obtained by growing Multi Wall Carbon Nanotubes on the surface of n-doped Silicon substrate. In the absence of light, the current flow is null until a junction threshold of about 2.4 V is reached, beyond which the dark current flows at room temperature with a very low intensity of few nA. When illuminated, a current of tens nA is observed at a drain voltage of about 1.5 V. At higher voltage the current intensity decreases according to a negative resistance of the order of MΩ. In the following we report details of tunneling photodiode realized and negative resistance characteristics.

  3. Cobalt release from inexpensive jewellery

    DEFF Research Database (Denmark)

    Thyssen, Jacob Pontoppidan; Jellesen, Morten Stendahl; Menné, Torkil

    2010-01-01

    . Conclusions: This study showed that only a minority of inexpensive jewellery purchased in Denmark released cobalt when analysed with the cobalt spot test. As fashion trends fluctuate and we found cobalt release from dark appearing jewellery, cobalt release from consumer items should be monitored in the future......Objectives: The aim was to study 354 consumer items using the cobalt spot test. Cobalt release was assessed to obtain a risk estimate of cobalt allergy and dermatitis in consumers who would wear the jewellery. Methods: The cobalt spot test was used to assess cobalt release from all items...

  4. Piezo-Phototronic Effect on Selective Electron or Hole Transport through Depletion Region of Vis-NIR Broadband Photodiode.

    Science.gov (United States)

    Zou, Haiyang; Li, Xiaogan; Peng, Wenbo; Wu, Wenzhuo; Yu, Ruomeng; Wu, Changsheng; Ding, Wenbo; Hu, Fei; Liu, Ruiyuan; Zi, Yunlong; Wang, Zhong Lin

    2017-08-01

    Silicon underpins nearly all microelectronics today and will continue to do so for some decades to come. However, for silicon photonics, the indirect band gap of silicon and lack of adjustability severely limit its use in applications such as broadband photodiodes. Here, a high-performance p-Si/n-ZnO broadband photodiode working in a wide wavelength range from visible to near-infrared light with high sensitivity, fast response, and good stability is reported. The absorption of near-infrared wavelength light is significantly enhanced due to the nanostructured/textured top surface. The general performance of the broadband photodiodes can be further improved by the piezo-phototronic effect. The enhancement of responsivity can reach a maximum of 78% to 442 nm illumination, the linearity and saturation limit to 1060 nm light are also significantly increased by applying external strains. The photodiode is illuminated with different wavelength lights to selectively choose the photogenerated charge carriers (either electrons or holes) passing through the depletion region, to investigate the piezo-phototronic effect on electron or hole transport separately for the first time. This is essential for studying the basic principles in order to develop a full understanding about piezotronics and it also enables the development of the better performance of optoelectronics. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Photodiode measurements in Nucte-II

    International Nuclear Information System (INIS)

    Machida, M.; Aramaki, E.A.; Takahashi, T.; Ohara, M.; Nogi, N.

    1989-01-01

    Direct measurements of light emission from plasma produced by a field reversed theta-pinch NUCTE-II have been performed by using a set of photodiode detectors. The analysis shows that the plasma light emission can be related to the bremsstrahlung radiation and it is used to identify η=2 rotational instability parameters as rotation direction, angular velocity, and radial and axial displacement of the plasma column. A rough estimate for the temporal behaviour of the electro temperature has also been obtained by using the photodiode signal together with He-Ne laser interferometer and flux excluded signals. (author) [pt

  6. Transient effects of ionizing radiation in Si, InGaAsP, GaAlSb, and Ge photodiodes

    International Nuclear Information System (INIS)

    Wiczer, J.J.; Barnes, C.E.; Dawson, L.R.

    1980-01-01

    Certain military applications require the continuous operation of optoelectronic information transfer systems during exposure to ionizing radiation. In such an environment the optical detector can be the system element which limits data transmission. We report here the measured electrical and optical characteristics of an irradiation tolerant photodiode fabricated from a double heterojunction structure in the gallium aluminum antimonide (GaAlSb) ternary semiconductor system. A series of tests at Sandia Laboratories' Relativistic Electron Beam Accelerator (REBA) subjected this device and commercially available photodiodes (made from silicon, germanium, and indium gallium arsenide phosphide) to dose rate levels of 10 7 to 10 8 rads/sec. The results of these tests show that the thin GaAlSb double heterojunction photodiode structure generates significantly less unwanted radiation induced current density than that of the next best commercial device

  7. Hybrid amplifier for calorimetry with photodiode readout

    Energy Technology Data Exchange (ETDEWEB)

    Sushkov, V V

    1994-12-31

    A hybrid surface mounted amplifier for the photodiode readout of the EM calorimeter has been developed. The main technical characteristics of the design are presented. The design able to math readout constraints for a high luminosity collider experiment is discussed. 10 refs., 2 tabs., 8 figs.

  8. Dose determination on buildup region using photodiodes

    International Nuclear Information System (INIS)

    Khoury, H.J.; Lopes, F.J.; Melo, F. de A.

    1989-01-01

    A clinical dosemeter using photodiode BPW-34 was developed, allowing the determination of dose on buildup region. The measures were made with X-rays beam of linear accelerator and with gamma radiation of cobalt 60. The results were compared with others made in a ionization chamber. (C.G.C.) [pt

  9. Comparative study of various pixel photodiodes for digital radiography: Junction structure, corner shape and noble window opening

    Science.gov (United States)

    Kang, Dong-Uk; Cho, Minsik; Lee, Dae Hee; Yoo, Hyunjun; Kim, Myung Soo; Bae, Jun Hyung; Kim, Hyoungtaek; Kim, Jongyul; Kim, Hyunduk; Cho, Gyuseong

    2012-05-01

    Recently, large-size 3-transistors (3-Tr) active pixel complementary metal-oxide silicon (CMOS) image sensors have been being used for medium-size digital X-ray radiography, such as dental computed tomography (CT), mammography and nondestructive testing (NDT) for consumer products. We designed and fabricated 50 µm × 50 µm 3-Tr test pixels having a pixel photodiode with various structures and shapes by using the TSMC 0.25-m standard CMOS process to compare their optical characteristics. The pixel photodiode output was continuously sampled while a test pixel was continuously illuminated by using 550-nm light at a constant intensity. The measurement was repeated 300 times for each test pixel to obtain reliable results on the mean and the variance of the pixel output at each sampling time. The sampling rate was 50 kHz, and the reset period was 200 msec. To estimate the conversion gain, we used the mean-variance method. From the measured results, the n-well/p-substrate photodiode, among 3 photodiode structures available in a standard CMOS process, showed the best performance at a low illumination equivalent to the typical X-ray signal range. The quantum efficiencies of the n+/p-well, n-well/p-substrate, and n+/p-substrate photodiodes were 18.5%, 62.1%, and 51.5%, respectively. From a comparison of pixels with rounded and rectangular corners, we found that a rounded corner structure could reduce the dark current in large-size pixels. A pixel with four rounded corners showed a reduced dark current of about 200fA compared to a pixel with four rectangular corners in our pixel sample size. Photodiodes with round p-implant openings showed about 5% higher dark current, but about 34% higher sensitivities, than the conventional photodiodes.

  10. Comparative study of various pixel photodiodes for digital radiography: junction structure, corner shape and noble window opening

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Dong-Uk; Cho, Min-Sik; Lee, Dae-Hee; Yoo, Hyun-Jun; Kim, Myung-Soo; Bae, Jun-Hyung; Kim, Hyoung-Taek; Kim, Jong-Yul; Kim, Hyun-Duk; Cho, Gyu-Seong [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2012-05-15

    Recently, large-size 3-transistors (3-Tr) active pixel complementary metal-oxide silicon (CMOS) image sensors have been being used for medium-size digital X-ray radiography, such as dental computed tomography (CT), mammography and nondestructive testing (NDT) for consumer products. We designed and fabricated 50 μm x 50 μm 3-Tr test pixels having a pixel photodiode with various structures and shapes by using the TSMC 0.25-m standard CMOS process to compare their optical characteristics. The pixel photodiode output was continuously sampled while a test pixel was continuously illuminated by using 550-nm light at a constant intensity. The measurement was repeated 300 times for each test pixel to obtain reliable results on the mean and the variance of the pixel output at each sampling time. The sampling rate was 50 kHz, and the reset period was 200 msec. To estimate the conversion gain, we used the mean-variance method. From the measured results, the n-well/p-substrate photodiode, among 3 photodiode structures available in a standard CMOS process, showed the best performance at a low illumination equivalent to the typical X-ray signal range. The quantum efficiencies of the n+/p-well, n-well/p-substrate, and n+/p-substrate photodiodes were 18.5%, 62.1%, and 51.5%, respectively. From a comparison of pixels with rounded and rectangular corners, we found that a rounded corner structure could reduce the dark current in large-size pixels. A pixel with four rounded corners showed a reduced dark current of about 200 fA compared to a pixel with four rectangular corners in our pixel sample size. Photodiodes with round p-implant openings showed about 5% higher dark current, but about 34% higher sensitivities, than the conventional photodiodes.

  11. An InP/Si heterojunction photodiode fabricated by self-aligned corrugated epitaxial lateral overgrowth

    International Nuclear Information System (INIS)

    Sun, Y. T.; Omanakuttan, G.; Lourdudoss, S.

    2015-01-01

    An n-InP/p-Si heterojunction photodiode fabricated by corrugated epitaxial lateral overgrowth (CELOG) method is presented. N-InP/p-Si heterojunction has been achieved from a suitable pattern containing circular shaped openings in a triangular lattice on the InP seed layer on p-Si substrate and subsequent CELOG of completely coalesced n-InP. To avoid current path through the seed layer in the final photodiode, semi-insulating InP:Fe was grown with adequate thickness prior to n-InP growth in a low pressure hydride vapor phase epitaxy reactor. The n-InP/p-Si heterointerface was analyzed by scanning electron microscopy and Raman spectroscopy. Room temperature cross-sectional photoluminescence (PL) mapping illustrates the defect reduction effect in InP grown on Si by CELOG method. The InP PL intensity measured above the InP/Si heterojunction is comparable to that of InP grown on a native planar substrate indicating low interface defect density of CELOG InP despite of 8% lattice mismatch with Si. The processed n-InP/p-Si heterojunction photodiodes show diode characteristics from the current-voltage (I-V) measurements with a dark current density of 0.324 mA/cm 2 at a reverse voltage of −1 V. Under the illumination of AM1.5 conditions, the InP/Si heterojunction photodiode exhibited photovoltaic effect with an open circuit voltage of 180 mV, a short circuit current density of 1.89 mA/cm 2 , an external quantum efficiency of 4.3%, and an internal quantum efficiency of 6.4%. This demonstration of epitaxially grown InP/Si heterojunction photodiode will open the door for low cost and high efficiency solar cells and photonic integration of III-Vs on silicon

  12. Performance test of Si PIN photodiode line scanner for thermal neutron detection

    Energy Technology Data Exchange (ETDEWEB)

    Totsuka, Daisuke, E-mail: totsuka@imr.tohoku.ac.jp [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Nihon Kessho Kogaku Co., Ltd., 810-5 Nobe-cho Tatebayashi, Gunma 374-0047 (Japan); Yanagida, Takayuki [New Industry Creation Hatchery Center (NICHe) 6-6-10 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579 (Japan); Fukuda, Kentaro; Kawaguchi, Noriaki [Tokuyama Corp., 3 Shibuya Shibuya-ku, Tokyo 150-8383 (Japan); Fujimoto, Yutaka [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Pejchal, Jan [Institute of Physics AS CR, Cukrovarnicka 10, Prague 6, 162-53 (Czech Republic); Yokota, Yuui [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Yoshikawa, Akira [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); New Industry Creation Hatchery Center (NICHe) 6-6-10 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579 (Japan)

    2011-12-11

    Thermal neutron imaging using Si PIN photodiode line scanner and Eu-doped LiCaAlF{sub 6} crystal scintillator has been developed. The pixel dimensions of photodiode are 1.18 mm (width) Multiplication-Sign 3.8 mm (length) with 0.4 mm gap and the module has 192 channels in linear array. The emission peaks of Eu-doped LiCaAlF{sub 6} after thermal neutron excitation are placed at 370 and 590 nm, and the corresponding photon sensitivities of photodiode are 0.04 and 0.34 A/W, respectively. Polished scintillator blocks with a size of 1.18 mm (width) Multiplication-Sign 3.8 mm (length) Multiplication-Sign 5.0 mm (thickness) were wrapped by several layers of Teflon tapes as a reflector and optically coupled to the photodiodes by silicone grease. JRR-3 MUSASI beam line emitting 13.5 meV thermal neutrons with the flux of 8 Multiplication-Sign 10{sup 5} n/cm{sup 2} s was used for the imaging test. As a subject for imaging, a Cd plate was moved at the speed of 50 mm/s perpendicular to the thermal neutron beam. Analog integration time was set to be 416.6 {mu}s, then signals were converted by a delta-sigma A/D converter. After the image processing, we successfully obtained moving Cd plate image under thermal neutron irradiation using PIN photodiode line scanner coupled with Eu-doped LiCaAlF{sub 6} scintillator.

  13. Performance test of Si PIN photodiode line scanner for thermal neutron detection

    International Nuclear Information System (INIS)

    Totsuka, Daisuke; Yanagida, Takayuki; Fukuda, Kentaro; Kawaguchi, Noriaki; Fujimoto, Yutaka; Pejchal, Jan; Yokota, Yuui; Yoshikawa, Akira

    2011-01-01

    Thermal neutron imaging using Si PIN photodiode line scanner and Eu-doped LiCaAlF 6 crystal scintillator has been developed. The pixel dimensions of photodiode are 1.18 mm (width)×3.8 mm (length) with 0.4 mm gap and the module has 192 channels in linear array. The emission peaks of Eu-doped LiCaAlF 6 after thermal neutron excitation are placed at 370 and 590 nm, and the corresponding photon sensitivities of photodiode are 0.04 and 0.34 A/W, respectively. Polished scintillator blocks with a size of 1.18 mm (width)×3.8 mm (length)×5.0 mm (thickness) were wrapped by several layers of Teflon tapes as a reflector and optically coupled to the photodiodes by silicone grease. JRR-3 MUSASI beam line emitting 13.5 meV thermal neutrons with the flux of 8×10 5 n/cm 2 s was used for the imaging test. As a subject for imaging, a Cd plate was moved at the speed of 50 mm/s perpendicular to the thermal neutron beam. Analog integration time was set to be 416.6 μs, then signals were converted by a delta-sigma A/D converter. After the image processing, we successfully obtained moving Cd plate image under thermal neutron irradiation using PIN photodiode line scanner coupled with Eu-doped LiCaAlF 6 scintillator.

  14. Pin-photodiode array for the measurement of fan-beam energy and air kerma distributions of X-ray CT scanners.

    Science.gov (United States)

    Haba, Tomonobu; Koyama, Shuji; Aoyama, Takahiko; Kinomura, Yutaka; Ida, Yoshihiro; Kobayashi, Masanao; Kameyama, Hiroshi; Tsutsumi, Yoshinori

    2016-07-01

    Patient dose estimation in X-ray computed tomography (CT) is generally performed by Monte Carlo simulation of photon interactions within anthropomorphic or cylindrical phantoms. An accurate Monte Carlo simulation requires an understanding of the effects of the bow-tie filter equipped in a CT scanner, i.e. the change of X-ray energy and air kerma along the fan-beam arc of the CT scanner. To measure the effective energy and air kerma distributions, we devised a pin-photodiode array utilizing eight channels of X-ray sensors arranged at regular intervals along the fan-beam arc of the CT scanner. Each X-ray sensor consisted of two plate type of pin silicon photodiodes in tandem - front and rear photodiodes - and of a lead collimator, which only allowed X-rays to impinge vertically to the silicon surface of the photodiodes. The effective energy of the X-rays was calculated from the ratio of the output voltages of the photodiodes and the dose was calculated from the output voltage of the front photodiode using the energy and dose calibration curves respectively. The pin-photodiode array allowed the calculation of X-ray effective energies and relative doses, at eight points simultaneously along the fan-beam arc of a CT scanner during a single rotation of the scanner. The fan-beam energy and air kerma distributions of CT scanners can be effectively measured using this pin-photodiode array. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  15. A compact readout system for multi-pixel hybrid photodiodes

    International Nuclear Information System (INIS)

    Datema, C.P.; Meng, L.J.; Ramsden, D.

    1999-01-01

    Although the first Multi-pixel Hybrid Photodiode (M-HPD) was developed in the early 1990s by Delft Electronic Products, the main obstacle to its application has been the lack of availability of a compact read-out system. A fast, parallel readout system has been constructed for use with the earlier 25-pixel tube with High-energy Physics applications in mind. The excellent properties of the recently developed multi-pixel hybrid photodiodes (M-HPD) will be easier to exploit following the development of the new hybrid read-out circuits described in this paper. This system will enable all of the required read-out functions to be accommodate on a single board into which the M-HPD is plugged. The design and performance of a versatile system is described in which a trigger-signal, derived from the common-side of the silicon anode in the M-HPD, is used to trigger the readout of the 60-anode pixels in the M-HPD. The multi-channel amplifier section is based on the use of a new, commercial VLSI chip, whilst the read-out sequencer uses a chip of its own design. The common anode signal is processed by a fast amplifier and discriminator to provide a trigger signal when a single event is detected. In the prototype version, the serial analogue output data-stream is processed using a PC-mounted, high speed ADC. Results obtained using the new read-out system in a compact gamma-camera and with a small muon tracking-chamber demonstrate the low-noise performance of the system. The application of this read-out system in other position-sensitive or multi-anode photomultiplier tube applications are also described

  16. Silicon photonics fundamentals and devices

    CERN Document Server

    Deen, M Jamal

    2012-01-01

    The creation of affordable high speed optical communications using standard semiconductor manufacturing technology is a principal aim of silicon photonics research. This would involve replacing copper connections with optical fibres or waveguides, and electrons with photons. With applications such as telecommunications and information processing, light detection, spectroscopy, holography and robotics, silicon photonics has the potential to revolutionise electronic-only systems. Providing an overview of the physics, technology and device operation of photonic devices using exclusively silicon and related alloys, the book includes: * Basic Properties of Silicon * Quantum Wells, Wires, Dots and Superlattices * Absorption Processes in Semiconductors * Light Emitters in Silicon * Photodetectors , Photodiodes and Phototransistors * Raman Lasers including Raman Scattering * Guided Lightwaves * Planar Waveguide Devices * Fabrication Techniques and Material Systems Silicon Photonics: Fundamentals and Devices outlines ...

  17. Pentacene-based photodiode with Schottky junction

    International Nuclear Information System (INIS)

    Lee, Jiyoul; Hwang, D.K.; Park, C.H.; Kim, S.S.; Im, Seongil

    2004-01-01

    We have fabricated a metal/organic semiconductor Schottky photodiode based on Al/pentacene junction. Since the energy band gap of thin solid pentacene was determined to be 1.82 eV, as characterized by direct absorption spectroscopy, we measured spectral photoresponses on our Schottky photodiode in the monochromatic light illumination range of 325-650 nm applying a reverse bias of -2 V. The main features of photo-response spectra were found to shift from those of direct absorption spectra toward higher photon energies. It is because the direct absorption spectra mainly show exciton level peaks rather than the true highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) gaps while the photo-response spectra clearly represents the true HOMO-LUMO gap. Our photo-response spectra reveal 1.97 eV as the HOMO-LUMO gap

  18. Silicon radiation detector

    International Nuclear Information System (INIS)

    Benc, I.; Kerhart, J.; Kopecky, J.; Krca, P.; Veverka, V.; Weidner, M.; Weinova, H.

    1992-01-01

    The silicon radiation detector, which is designed for the detection of electrons with energies above 500 eV and of radiation within the region of 200 to 1100 nm, comprises a PIN or PNN + type photodiode. The active acceptor photodiode is formed by a detector surface of shallow acceptor diffusion surrounded by a collector band of deep acceptor diffusion. The detector surface of shallow P-type diffusion with an acceptor concentration of 10 15 to 10 17 atoms/cm 3 reaches a depth of 40 to 100 nm. One sixth to one eighth of the collector band width is overlapped by the P + collector band at a width of 150 to 300 μm with an acceptor concentration of 10 20 to 10 21 atoms/cm 3 down a depth of 0.5 to 3 μm. This band is covered with a conductive layer, of NiCr for instance. (Z.S.)

  19. Results from a test of a Cu-scintillator calorimeter module with photodiode readout

    International Nuclear Information System (INIS)

    Fischer, F.; Kiesling, C.; Lorenz, E.; Mageras, G.; Scholz, S.

    1986-05-01

    A calorimeter module of 17 radiation lengths depth has been built. Wavelength shifter (WLS) bars coupled to rectangular silicon photodiodes (PD's) are use as readout. Considerations in the design of the WLS bars, with particular emphasis on optimising the efficiency for PD readout, are discussed. The energy resolution for electrons has been determined to be about 9%/√E between 2 and 50 GeV. The response to hadrons is presented and the prospects for the construction of a full-sized hadron calorimeter are discussed. (orig.)

  20. Highly segmented large-area hybrid photodiodes with bialkali photocathodes and enclosed VLSI readout electronics

    CERN Document Server

    Braem, André; Filthaut, Frank; Go, A; Joram, C; Weilhammer, Peter; Wicht, P; Dulinski, W; Séguinot, Jacques; Wenzel, H; Ypsilantis, Thomas

    2000-01-01

    We report on the principles, design, fabrication, and operation of a highly segmented, large-area hybrid photodiode, which is being developed in the framework of the LHCb RICH project. The device consists of a cylindrical, 127 mm diameter vacuum envelope capped with a spherical borosilicate UV-glass entrance window, with an active-to-total-area fraction of 81A fountain-focusing electron optics is used to demagnify the image onto a 50 mm diameter silicon sensor, containing 2048 pads of size 1*1 mm/sup 2/. (10 refs).

  1. A photodiode amplifier system for pulse-by-pulse intensity measurement of an x-ray free electron laser.

    Science.gov (United States)

    Kudo, Togo; Tono, Kensuke; Yabashi, Makina; Togashi, Tadashi; Sato, Takahiro; Inubushi, Yuichi; Omodani, Motohiko; Kirihara, Yoichi; Matsushita, Tomohiro; Kobayashi, Kazuo; Yamaga, Mitsuhiro; Uchiyama, Sadayuki; Hatsui, Takaki

    2012-04-01

    We have developed a single-shot intensity-measurement system using a silicon positive-intrinsic-negative (PIN) photodiode for x-ray pulses from an x-ray free electron laser. A wide dynamic range (10(3)-10(11) photons/pulse) and long distance signal transmission (>100 m) were required for this measurement system. For this purpose, we developed charge-sensitive and shaping amplifiers, which can process charge pulses with a wide dynamic range and variable durations (ns-μs) and charge levels (pC-μC). Output signals from the amplifiers were transmitted to a data acquisition system through a long cable in the form of a differential signal. The x-ray pulse intensities were calculated from the peak values of the signals by a waveform fitting procedure. This system can measure 10(3)-10(9) photons/pulse of ~10 keV x-rays by direct irradiation of a silicon PIN photodiode, and from 10(7)-10(11) photons/pulse by detecting the x-rays scattered by a diamond film using the silicon PIN photodiode. This system gives a relative accuracy of ~10(-3) with a proper gain setting of the amplifiers for each measurement. Using this system, we succeeded in detecting weak light at the developmental phase of the light source, as well as intense light during lasing of the x-ray free electron laser. © 2012 American Institute of Physics

  2. Simulations of Si-PIN photodiode based detectors for underground explosives enhanced by ammonium nitrate

    Science.gov (United States)

    Yücel, Mete; Bayrak, Ahmet; Yücel, Esra Barlas; Ozben, Cenap S.

    2018-02-01

    Massive Ammonium Nitrate (NH4-NO3) based explosives buried underground are commonly used in terror attacks. These explosives can be detected using neutron scattering method with some limitations. Simulations are very useful tools for designing a possible detection system for these kind of explosives. Geant4 simulations were used for generating neutrons at 14 MeV energy and tracking them through the scattering off the explosive embedded in soil. Si-PIN photodiodes were used as detector elements in the design for their low costs and simplicity for signal readout electronics. Various neutron-charge particle converters were applied on to the surface of the photodiodes to increase the detection efficiency. Si-PIN photodiodes coated with 6LiF provided the best result for a certain energy interval. Energy depositions in silicon detector from all secondary particles generated including photons were taken into account to generate a realistic background. Humidity of soil, one of the most important parameter for limiting the detection, was also studied.

  3. Relative performance of several inexpensive accelerometers

    Science.gov (United States)

    Evans, John R.; Rogers, John A.

    1995-01-01

    We examined the performance of several low-cost accelerometers for highly cost-driven applications in recording earthquake strong motion. We anticipate applications for such sensors in providing the lifeline and emergency-response communities with an immediate, comprehensive picture of the extent and characteristics of likely damage. We also foresee their use as 'filler' instruments sited between research-grade instruments to provide spatially detailed and near-field records of large earthquakes (on the order of 1000 stations at 600-m intervals in San Fernando Valley, population 1.2 million, for example). The latter applications would provide greatly improved attenuation relationships for building codes and design, the first examples of mainshock information (that is, potentially nonlinear regime) for microzonation, and a suite of records for structural engineers. We also foresee possible applications in monitoring structural inter-story drift during earthquakes, possibly leading to local and remote alarm functions as well as design criteria. This effort appears to be the first of its type at the USGS. It is spurred by rapid advances in sensor technology and the recognition of potential non-classical applications. In this report, we estimate sensor noise spectra, relative transfer functions and cross-axis sensitivity of six inexpensive sensors. We tested three micromachined ('silicon-chip') sensors in addition to classical force-balance and piezoelectric examples. This sample of devices is meant to be representative, not comprehensive. Sensor noise spectra were estimated by recording system output with the sensor mounted on a pneumatically supported 545-kg optical-bench isolation table. This isolation table appears to limit ground motion to below our system noise level. These noise estimates include noise introduced by signal-conditioning circuitry, the analog-to-digital converter (ADC), and noise induced in connecting wiring by ambient electromagnetic fields in

  4. Liquid-helium scintillation detection with germanium photodiodes

    International Nuclear Information System (INIS)

    Luke, P.N.; Haller, E.E.; Steiner, H.M.

    1982-05-01

    Special high-purity germanium photodiodes have been developed for the direct detection of vacuum ultraviolet scintillations in liquid helium. The photodiodes are immersed in the liquid helium, and scintillations are detected through one of the bare sides of the photodiodes. Test results with scintillation photons produced by 5.3-MeV α particles are presented. The use of these photodiodes as liquid-helium scintillation detectors may offer substantial improvements over the alternate detection method requiring the use of wavelength shifters and photomultiplier tubes

  5. Radiation damage effect on avalanche photodiodes

    CERN Document Server

    Baccaro, S; Cavallari, F; Da Ponte, V; Deiters, K; Denes, P; Diemoz, M; Kirn, Th; Lintern, A L; Longo, E; Montecchi, M; Musienko, Y; Pansart, J P; Renker, D; Reucroft, S; Rosi, G; Rusack, R; Ruuska, D; Stephenson, R; Torbet, M J

    1999-01-01

    Avalanche Photodiodes have been chosen as photon sensors for the electromagnetic calorimeter of the CMS experiment at the LHC. These sensors should operate in the 4T magnetic field of the experiment. Because of the high neutron radiation in the detector extensive studies have been done by the CMS collaboration on the APD neutron radiation damage. The characteristics of these devices after irradiation have been analized, with particular attention to the quantum efficiency and the dark current. The recovery of the radiation induced dark current has been studied carefully at room temperature and at slightly lower and higher temperatures. The temperature dependence of the defects decay-time has been evaluated.

  6. Responses of the multi-photodiode readout

    International Nuclear Information System (INIS)

    Tamai, K.

    2000-01-01

    The responses for a signal in various configurations of photodiodes (PDs) and preamplifiers are analyzed by Laplace transformation. The electronic noise in the configuration is derived using the Fourier transformation. The responses and noise are obtained by an analogical extension of the impedance from a single-PD configuration to the multi-PD configuration; however, the noise is not so simple when connected in series. Using the results, we evaluate the energy resolution of the configurations. A series PD connection realizes a better resolution than a parallel connection in the fast shaping

  7. Room Temperature Direct Band Gap Emission from Ge p-i-n Heterojunction Photodiodes

    Directory of Open Access Journals (Sweden)

    E. Kasper

    2012-01-01

    Full Text Available Room temperature direct band gap emission is observed for Si-substrate-based Ge p-i-n heterojunction photodiode structures operated under forward bias. Comparisons of electroluminescence with photoluminescence spectra allow separating emission from intrinsic Ge (0.8 eV and highly doped Ge (0.73 eV. Electroluminescence stems from carrier injection into the intrinsic layer, whereas photoluminescence originates from the highly n-doped top layer because the exciting visible laser wavelength is strongly absorbed in Ge. High doping levels led to an apparent band gap narrowing from carrier-impurity interaction. The emission shifts to higher wavelengths with increasing current level which is explained by device heating. The heterostructure layer sequence and the light emitting device are similar to earlier presented photodetectors. This is an important aspect for monolithic integration of silicon microelectronics and silicon photonics.

  8. Improvement of n-ZnO/p-Si photodiodes by embedding of silver nanoparticles

    International Nuclear Information System (INIS)

    Hu, Zhan-Shuo; Hung, Fei-Yi; Chang, Shoou-Jinn; Chen, Kuan-Jen; Tseng, Yi-Wei; Huang, Bohr-Ran; Lin, Bo-Cheng; Chou, Wei-Yang; Chang, Jay

    2011-01-01

    The photo-current of n-ZnO/p-Si heterojunction photodiodes was improved by embedding Ag nanoparticles in the interface (ZnO/nano-P Ag /p-Si), and the ratio between photo- and dark-current increased by about three orders more than that of a n-ZnO/p-Si specimen. The improvement in the photo-current resulted from the light scattering of embedded Ag nanoparticles. The I–V curve of n-ZnO/p-Si degraded after thermal treatment (A-ZnO/p-Si) because the silicon robbed the oxygen from ZnO to form amorphous silicon dioxide and left an oxygen vacancy. Notably, the properties of ZnO/nano-P Ag /p-Si were better in the time-dependent photoresponse under 10 V bias. Ag nanoparticles (15–20 nm) scattered the UV light randomly and increased the probability for the absorption of ZnO to enhance the properties of the photodiode.

  9. Photon-counting monolithic avalanche photodiode arrays for the super collider

    International Nuclear Information System (INIS)

    Ishaque, A.N.; Castleberry, D.E.; Rougeot, H.M.

    1994-01-01

    In fiber tracking, calorimetry, and other high energy and nuclear physics experiments, the need arises to detect an optical signal consisting of a few photons (in some cases a single photoelectron) with a detector insensitive to magnetic fields. Previous attempts to detect a single photoelectron have involved avalanche photodiodes (APDs) operated in the Geiger mode, the visible light photon counter, and a photomultiplier tube with an APD as the anode. In this paper it is demonstrated that silicon APDs, biased below the breakdown voltage, can be used to detect a signal of a few photons with conventional pulse counting circuitry at room temperature. Moderate cooling, it is further argued, could make it possible to detect a single photoelectron. Monolithic arrays of silicon avalanche photodiodes fabricated by Radiation Monitoring Devices, Inc. (RMD) were evaluated for possible use in the Super Collider detector systems. Measurements on 3 element x 3 element (2 mm pitch) APD arrays, using pulse counting circuitry with a charge sensitive amplifier (CSA) and a Gaussian filter, are reported and found to conform to a simple noise model. The model is used to obtain the optimal operating point. Experimental results are described in Section II, modeling results in Section III, and the conclusions are summarized in Section IV

  10. Analysis of genetically modified organisms by pyrosequencing on a portable photodiode-based bioluminescence sequencer.

    Science.gov (United States)

    Song, Qinxin; Wei, Guijiang; Zhou, Guohua

    2014-07-01

    A portable bioluminescence analyser for detecting the DNA sequence of genetically modified organisms (GMOs) was developed by using a photodiode (PD) array. Pyrosequencing on eight genes (zSSIIb, Bt11 and Bt176 gene of genetically modified maize; Lectin, 35S-CTP4, CP4EPSPS, CaMV35S promoter and NOS terminator of the genetically modified Roundup ready soya) was successfully detected with this instrument. The corresponding limit of detection (LOD) was 0.01% with 35 PCR cycles. The maize and soya available from three different provenances in China were detected. The results indicate that pyrosequencing using the small size of the detector is a simple, inexpensive, and reliable way in a farm/field test of GMO analysis. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Low-cost amplifier for alpha detection with photodiode

    Energy Technology Data Exchange (ETDEWEB)

    Domienikan, Cláudio; Costa, Priscila; Genezini, Frederico A.; Zahn, Guilherme S., E-mail: clanikan@ipen.br, E-mail: pcosta@ipen.br, E-mail: fredzini@ipen.br, E-mail: gzahn@ipen.br [Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil)

    2017-07-01

    A low-cost amplifier for Hamamatsu S3590-09 PIN photodiode to be used in alpha detection is presented. This amplifier consists basically of two circuits: a pulse preamplifier and a shaper-driver. The PIN photodiode is reverse-biased and connected to a charge preamplifier input. Incident alpha particles generate a small current pulse in the photodiode. The integrating circuit of the low noise preamplifier transforms current pulse into a voltage pulse with amplitude proportional to the charge carried by the current pulse. The shaper-driver consists of a differentiator and an integrator and is responsible for filtering and further amplifying the preamplifier signal, generating a NIM-compatible energy pulse. The performance of the set photodiode-amplifier was successively tested through the use of a {sup 243}Am radioactive source. The low-cost photodiode amplifier was designed and constructed at IPEN - CNEN/SP using national components and expertise. (author)

  12. Feasibility studies of using thin entrance window photodiodes for clinical electron beam dosimetry

    International Nuclear Information System (INIS)

    Nascimento, Cristina R.; Asfora, Viviane K.; Barros, Vinicius S.M.; Gonçalves, Josemary A.C.; Andrade, Lucas F.R.; Khoury, Helen J.; Bueno, Carmen C.

    2017-01-01

    The response of the commercial XRA-24 PIN photodiode (5.76 mm 2 active area) for clinical electron beam dosimetry covering the range of 8-12 MeV was investigated. Within this energy range, the charge generated in the diode's sensitive volume is linearly dependent on the absorbed dose up to 320 cGy. However, charge sensitivity coefficients evidenced that the dose response of the diode is slightly dependent on the electron beam energy. Indeed, the diode's energy dependence was within 8.5% for 8-12MeV electron beams. On the other hand, it was also observed an excellent repeatability of these results with a variation coefficient (VC) lower than 0.4%, which is within the 1% tolerance limit recommended by the AAPM TG-62. Furthermore, the agreement between the percentage depth dose profiles (PDD) gathered with the diode and the ionization chamber allowed achieving the electron beam quality within 1% of that obtained with the ionization chamber. Based on these results, the photodiode XRA-24 can be a reliable and inexpensive alternative for electron beams dosimetry. (author)

  13. Feasibility studies of using thin entrance window photodiodes for clinical electron beam dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Nascimento, Cristina R.; Asfora, Viviane K.; Barros, Vinicius S.M.; Gonçalves, Josemary A.C.; Andrade, Lucas F.R.; Khoury, Helen J.; Bueno, Carmen C., E-mail: vsmdbarros@gmail.com, E-mail: vikhoury@gmail.com, E-mail: hjkhoury@gmail.com, E-mail: cristinaramos@smartsat.com.br, E-mail: josemary@ipen.br, E-mail: ccbueno@ipen.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil); Instituto Federal de Educação, Ciência e Tecnologia de Pernambuco (IFPE), Recife-PE (Brazil). Departamento de Energia Nuclear; Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Santa Casa de Misericórdia de Itabuna, BA (Brazil)

    2017-11-01

    The response of the commercial XRA-24 PIN photodiode (5.76 mm{sup 2} active area) for clinical electron beam dosimetry covering the range of 8-12 MeV was investigated. Within this energy range, the charge generated in the diode's sensitive volume is linearly dependent on the absorbed dose up to 320 cGy. However, charge sensitivity coefficients evidenced that the dose response of the diode is slightly dependent on the electron beam energy. Indeed, the diode's energy dependence was within 8.5% for 8-12MeV electron beams. On the other hand, it was also observed an excellent repeatability of these results with a variation coefficient (VC) lower than 0.4%, which is within the 1% tolerance limit recommended by the AAPM TG-62. Furthermore, the agreement between the percentage depth dose profiles (PDD) gathered with the diode and the ionization chamber allowed achieving the electron beam quality within 1% of that obtained with the ionization chamber. Based on these results, the photodiode XRA-24 can be a reliable and inexpensive alternative for electron beams dosimetry. (author)

  14. Determination of the electron-hole pair creation energy for semiconductors from the spectral responsivity of photodiodes

    CERN Document Server

    Scholze, F; Kuschnerus, P; Rabus, H; Richter, M; Ulm, G

    2000-01-01

    Ionizing radiation can be detected by the measurement of the charge carriers produced in a detector. The improved semiconductor technology now allows detectors operating near the physical limits of the detector materials to be designed. The mean energy required for producing an electron-hole pair, W, is a material property of the semiconductor. Here, the determination of W from the spectral responsivity of photodiodes is demonstrated. Using spectrally dispersed synchrotron radiation, different types of semiconductor photodiodes have been examined in the UV-, VUV-, and soft X-ray spectral range. Their spectral responsivity was determined with relative uncertainties between 0.4% and 1% using a cryogenic electrical-substitution radiometer as primary detector standard. Results are presented for silicon n-on-p junction photodiodes and for GaAsP/Au Schottky diodes at room temperature. The investigations for silicon covered the complete spectral range from 3 to 1500 eV, yielding a constant value W=(3.66+-0.03) eV fo...

  15. Diamond photodiodes for x-ray application

    Energy Technology Data Exchange (ETDEWEB)

    Distel, James R [Los Alamos National Laboratory; Smedley, John [BNL; Keister, Jeffrey W [BNL; Muller, Erik [STONY BROOK UNIV.; Jordan - Sweet, Jean [WATSON RESEARCH CENTER; Bohon, Jen [CASE WESTERN RESERVE UNIV.; Dong, Bin [NON LANL

    2009-01-01

    Single crystal high purity CVD diamonds have been metallized and calibrated as photodiodes at the National Synchrotron Light Source (NSLS). Current mode responsivity measurements have been made over a wide range (0.2-28 keV) of photon energies across several beamlines. Linear response has been achieved over ten orders of magnitude of incident flux, along with uniform spatial response. A simple model of responsivity has been used to describe the results, yielding a value of 13.3 {+-} 0.5 eV for the mean pair creation energy. The responsivity vs. photon energy data show a dip for photon energies near the carbon edge (284 eV), indicating incomplete charge collection for carriers created less than one micron from the metallized layer.

  16. Alpha particles spectrometer with photodiode PIN

    International Nuclear Information System (INIS)

    Chacon R, A.; Hernandez V, R.; Hernandez D, V. M.; Vega C, H. R.; Ramirez G, J.

    2009-10-01

    The radiation propagates in form of electromagnetic waves or corpuscular radiation; if the radiation energy causes ionization in environment that crosses it is considered ionizing radiation. To detect radiation several detectors types are used, if the radiation are alpha particles are used detectors proportional type or trace elements. In this work the design results, construction and tests of an alpha particles spectrometer are presented, which was designed starting from a photodiode PIN type. The system design was simulated with a code for electronic circuits. With results of simulation phase was constructed the electronic phase that is coupled to a multichannel analyzer. The resulting electronic is evaluated analyzing the electronic circuit performance before an alphas triple source and alpha radiation that produce two smoke detectors of domestic use. On the tests phase we find that the system allows obtain, in a multichannel, the pulses height spectrum, with which we calibrate the system. (Author)

  17. Inflation Fighters: An Inexpensive Du Nuoy Tensiometer.

    Science.gov (United States)

    Cohen, Sheldon H.

    1983-01-01

    Describes an inexpensive tensiometer, a balance consisting of a plastic drinking straw as the crossarm, a needle as a pivot, and wire loop counter balance to assure proper balance. The instrument permits the quantitative demonstration of interfacial tension and effects of various agents that modify it. (Author/JN)

  18. Inexpensive user tracking using Boltzmann machines

    NARCIS (Netherlands)

    Mocanu, E.; Mocanu, D.C.; Bou Ammar, H.; Zivkovic, Z.; Liotta, A.; Smirnov, E.

    2014-01-01

    Inexpensive user tracking is an important problem in various application domains such as healthcare, human-computer interaction, energy savings, safety, robotics, security and so on. Yet, it cannot be easily solved due to its probabilistic nature, high level of abstraction and uncertainties, on the

  19. Spiral silicon drift detectors

    International Nuclear Information System (INIS)

    Rehak, P.; Gatti, E.; Longoni, A.; Sampietro, M.; Holl, P.; Lutz, G.; Kemmer, J.; Prechtel, U.; Ziemann, T.

    1988-01-01

    An advanced large area silicon photodiode (and x-ray detector), called Spiral Drift Detector, was designed, produced and tested. The Spiral Detector belongs to the family of silicon drift detectors and is an improvement of the well known Cylindrical Drift Detector. In both detectors, signal electrons created in silicon by fast charged particles or photons are drifting toward a practically point-like collection anode. The capacitance of the anode is therefore kept at the minimum (0.1pF). The concentric rings of the cylindrical detector are replaced by a continuous spiral in the new detector. The spiral geometry detector design leads to a decrease of the detector leakage current. In the spiral detector all electrons generated at the silicon-silicon oxide interface are collected on a guard sink rather than contributing to the detector leakage current. The decrease of the leakage current reduces the parallel noise of the detector. This decrease of the leakage current and the very small capacities of the detector anode with a capacitively matched preamplifier may improve the energy resolution of Spiral Drift Detectors operating at room temperature down to about 50 electrons rms. This resolution is in the range attainable at present only by cooled semiconductor detectors. 5 refs., 10 figs

  20. Large area avalanche MRS-photodiodes for nuclear spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ermalitski, F A; Zalesski, V B

    1996-12-31

    Problems of application of avalanche photodiodes (APD) in readout systems of nuclear spectrometers are considered. APD`s with a large sensitive area of a diameter 1-5 mm and a high multiplication coefficient 200-1000 are created. MPS-photodiodes provide for the energy resolution 80% at temperature 231 K for detecting gamma-quanta with energy 662 keV. 4 refs.

  1. Geiger mode avalanche photodiodes for microarray systems

    Science.gov (United States)

    Phelan, Don; Jackson, Carl; Redfern, R. Michael; Morrison, Alan P.; Mathewson, Alan

    2002-06-01

    New Geiger Mode Avalanche Photodiodes (GM-APD) have been designed and characterized specifically for use in microarray systems. Critical parameters such as excess reverse bias voltage, hold-off time and optimum operating temperature have been experimentally determined for these photon-counting devices. The photon detection probability, dark count rate and afterpulsing probability have been measured under different operating conditions. An active- quench circuit (AQC) is presented for operating these GM- APDs. This circuit is relatively simple, robust and has such benefits as reducing average power dissipation and afterpulsing. Arrays of these GM-APDs have already been designed and together with AQCs open up the possibility of having a solid-state microarray detector that enables parallel analysis on a single chip. Another advantage of these GM-APDs over current technology is their low voltage CMOS compatibility which could allow for the fabrication of an AQC on the same device. Small are detectors have already been employed in the time-resolved detection of fluorescence from labeled proteins. It is envisaged that operating these new GM-APDs with this active-quench circuit will have numerous applications for the detection of fluorescence in microarray systems.

  2. Production of a square geometry Americium standard source for use with photodiodes

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Priscila; Geraldo, Bianca; Raele, Marcus P.; Marumo, Júlio T.; Vicente, Roberto; Zahn, Guilherme S.; Genezini, Frederico A., E-mail: priscila3.costa@usp.br, E-mail: fredzini@ipen.br [Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil)

    2017-07-01

    In the development of a thermal neutron detector using a square photodiode and a thin boron film, a radioactive calibration source with the same geometry was needed. An americium-243 standard source was produced by electrodeposition aiming at the calibration of a PIN-type silicon photodiode with a detection area of 10 x 10 mm{sup 2}. To produce the samples two tests were performed. In the first test, a square stainless steel plate (10 x 10 mm{sup 2}) was fixed on the surface of the conventional plate, which was removed after deposition. To reduce the loss of activity of the source, in the second test nail polish was applied on the silver plate leaving only an area of 10 x 10 mm{sup 2} without varnish coating. Once the electrodeposition process was completed, the activity concentration measurement was performed by alpha particle spectrometry. The first method presented a lower activity when compared to the total activity of Am-243 added initially. For the second method, the total activity was concentrate in the exposed square region (without nail polish). The results showed that it is possible to obtain a square geometry source; furthermore, the surrounding nail polish was not contaminated by {sup 243}Am. The comparison of these two approaches indicated that the second method was more efficient as it was possible to concentrate all the americium activity in the delimited square area. (author)

  3. Application of avalanche photodiodes for the measurement of actinides by alpha liquid scintillation counting

    International Nuclear Information System (INIS)

    Reboli, A.

    2005-10-01

    Alpha emitters analysis using liquid scintillation spectroscopy is often used when sensitivity and fast samples preparation are the important points. A more extensive use of this technique is until now limited by its poor resolution compared to alpha particle spectroscopy with semiconductor detectors. To improve the resolution and thus promote this method for the measurement of actinides in environment, we have tested silicon avalanche photodiodes (APD) as new detectors for scintillation photons. The set-up consists of a large area avalanche photodiode (16 mm diameter) coupled to a thin vial containing alpha-emitters within a liquid scintillation cocktail. After optimization of several parameters like bias voltage, temperature, counting geometry and composition of the scintillating cocktail, energy resolutions have been found to be better than those obtained with standard photomultiplier tubes (PMT): 5% (200 keV FWHM) for 232 Th and 4.2% (240 keV FWHM) for 236 Pu. Our results show that the improvement is due to less fluctuations associated with light collection since the spatial response of APDs is more uniform than that of PMTs. The expected gain on quantum efficiency (80% for APDs instead of 25% for PMTs) is nullified by a corresponding increase on electronic noise and excess noise factor. Significant better results are foreseen by using green scintillators (450 - 550 nm wavelengths region) with larger Stokes-shift and blue-enhanced APDs which reach their maximum quantum efficiency in this region. (author)

  4. A fully integrated optical detector with a-Si:H based color photodiodes

    Energy Technology Data Exchange (ETDEWEB)

    Watty, Krystian; Merfort, Christian; Seibel, Konstantin; Schoeler, Lars; Boehm, Markus [Institute for Microsystem Technologies (IMT), University of Siegen, Hoelderlinstr. 3, 57076 Siegen (Germany)

    2010-03-15

    The fabrication of an electrophoresis separation microchip with monolithic integrated excitation light source and variospectral photodiodes for absorption detection is presented in this paper. Microchip based separation techniques are essential elements in the development of fully integrated micro-total analysis systems ({mu}-TAS). An integrated microfluidic device, like an application specific lab-on-microchip (ALM) (Seibel et al., in: MRS Spring Meeting, San Francisco, USA, 2005 1), includes all components, necessary to perform a chemical analysis on chip and it can be used as a stand-alone unit directly at the point of sampling. Variospectral diodes based on hydrogenated amorphous silicon (a-Si:H) technology allow for advanced optical detection schemes, because the spectral sensitivity of the devices can be tailored to fit the emission of specific fluorescent markers. Important features of a-Si:H variospectral photodiodes are a high dynamic range, a bias-tunable spectral sensitivity and a very good linearity for the separation of mixed color signals. Principle of ALM device. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  5. High-performance silicon nanowire bipolar phototransistors

    Science.gov (United States)

    Tan, Siew Li; Zhao, Xingyan; Chen, Kaixiang; Crozier, Kenneth B.; Dan, Yaping

    2016-07-01

    Silicon nanowires (SiNWs) have emerged as sensitive absorbing materials for photodetection at wavelengths ranging from ultraviolet (UV) to the near infrared. Most of the reports on SiNW photodetectors are based on photoconductor, photodiode, or field-effect transistor device structures. These SiNW devices each have their own advantages and trade-offs in optical gain, response time, operating voltage, and dark current noise. Here, we report on the experimental realization of single SiNW bipolar phototransistors on silicon-on-insulator substrates. Our SiNW devices are based on bipolar transistor structures with an optically injected base region and are fabricated using CMOS-compatible processes. The experimentally measured optoelectronic characteristics of the SiNW phototransistors are in good agreement with simulation results. The SiNW phototransistors exhibit significantly enhanced response to UV and visible light, compared with typical Si p-i-n photodiodes. The near infrared responsivities of the SiNW phototransistors are comparable to those of Si avalanche photodiodes but are achieved at much lower operating voltages. Compared with other reported SiNW photodetectors as well as conventional bulk Si photodiodes and phototransistors, the SiNW phototransistors in this work demonstrate the combined advantages of high gain, high photoresponse, low dark current, and low operating voltage.

  6. Monolithic integration of a silica AWG and Ge photodiodes on Si photonic platform for one-chip WDM receiver.

    Science.gov (United States)

    Nishi, Hidetaka; Tsuchizawa, Tai; Kou, Rai; Shinojima, Hiroyuki; Yamada, Takashi; Kimura, Hideaki; Ishikawa, Yasuhiko; Wada, Kazumi; Yamada, Koji

    2012-04-09

    On the silicon (Si) photonic platform, we monolithically integrated a silica-based arrayed-waveguide grating (AWG) and germanium (Ge) photodiodes (PDs) using low-temperature fabrication technology. We confirmed demultiplexing by the AWG, optical-electrical signal conversion by Ge PDs, and high-speed signal detection at all channels. In addition, we mounted a multichannel transimpedance amplifier/limiting amplifier (TIA/LA) circuit on the fabricated AWG-PD device using flip-chip bonding technology. The results show the promising potential of our Si photonic platform as a photonics-electronics convergence.

  7. Thermal imager based on the array light sensor device of 128×128 CdHgTe-photodiodes

    Directory of Open Access Journals (Sweden)

    Reva V. P.

    2010-08-01

    Full Text Available The results of investigation of developed thermal imager for middle (3—5 µm infrared region are presented and its applications features are discussed. The thermal imager consists of cooled to 80 K 128×128 diodes focal plane array on the base of cadmium–mercury–telluride compound and cryostat with temperature checking system. The photodiode array is bonded with readout device (silicon focal processor via indium microcontacts. The measured average value of noise equivalent temperature difference was NETD= 20±4 mK (background radiation temperature T = 300 K, field of view 2θ = 180°, the cooled diaphragm was not used.

  8. Radiation damage of multipixel Geiger-mode avalanche photodiodes irradiated with low-energy γ's and electrons

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Y.; Yun, Y. B. [Yonsei University, Seoul (Korea, Republic of); Ha, J. M. [Yonsei University, Seoul (Korea, Republic of); Electronics and Telecommunications Research Institute, Daejeon (Korea, Republic of); Lee, J. S.; Yoon, Y. S. [Electronics and Telecommunications Research Institute, Daejeon (Korea, Republic of); Eun, J. W. [Namseoul University, Cheonan (Korea, Republic of)

    2012-05-15

    A few types of multipipixel Geiger-mode avalanche photodiodes (also referred to as silicon photomultipliers SiPMs) are irradiated with 1 to 2.5 MeV γ's and electrons. We characterize radiation damage effects appearing in the reverse bias current, the dark current and count rate, the pixel gain, and the photon detection efficiency of the devices. An interesting observation on the dark current and count rate is made and linked to the specific damage caused by the irradiation.

  9. A New and Inexpensive Pyranometer for the Visible Spectral Range

    OpenAIRE

    Martínez, Miguel A.; Andújar, José M.; Enrique, Juan M.

    2009-01-01

    This paper presents the design, construction and testing of a new photodiode-based pyranometer for the visible spectral range (approx. 400 to 750 nm), whose principal characteristics are: accuracy, ease of connection, immunity to noise, remote programming and operation, interior temperature regulation, cosine error minimisation and all this at a very low cost, tens of times lower than that of commercial thermopile-based devices. This new photodiode-based pyranometer overcomes traditional prob...

  10. Response of CMS avalanche photo-diodes to low energy neutrons

    Science.gov (United States)

    Brown, R. M.; Deiters, K.; Ingram, Q.; Renker, D.

    2012-12-01

    The response of the Avalanche Photo-diodes (APDs) installed in the CMS detector at the LHC to neutrons from 241AmBe and 252Cf sources is reported. Signals in size equivalent to those of up to 106 photo-electrons with the nominal APD gain are observed. Measurements with an APD with the protective epoxy coating removed and with the source placed behind the APD show that there is an important response due to recoil protons from neutron interactions with the hydrogen in the epoxy, in addition to signals from neutron interactions with the silicon of the diode. The effective gain of these signals is much smaller than the diode's nominal gain.

  11. A low-noise, wideband, integrated CMOS transimpedance preamplifier for photodiode applications

    International Nuclear Information System (INIS)

    Binkley, D.M.; Paulus, M.J.; Casey, M.E.; Rochelle, J.M.

    1992-01-01

    In this paper, a low-noise, wideband, integrated CMOS transimpedance preamplifier is presented for silicon avalanche photodiode (APD) applications. The preamplifier, fabricated in a standard 2μ CMOS technology, features a transimpedance gain of 45 kΩ, a risetime of 22 ns, a series noise of 1.6nV/Hz 1/2 , and a wideband equivalent input-noise current of 12 nA for a source capacitance of 12 pF. The measured 22 Na timing resolution of 9.2-ns FWHM and energy resolution of 22.4% FWHM for the RCA C30994 BGO/APD detector module coupled to the preamplifier is comparable to the performance reported using charge-sensitive preamplifiers. This illustrates that transimpedance preamplifiers should be considered for APD applications, especially where APD noise current dominates noise from feedback resistors in the 1--kΩ to 50-kΩ range

  12. Simple, inexpensive computerized rodent activity meters.

    Science.gov (United States)

    Horton, R M; Karachunski, P I; Kellermann, S A; Conti-Fine, B M

    1995-10-01

    We describe two approaches for using obsolescent computers, either an IBM PC XT or an Apple Macintosh Plus, to accurately quantify spontaneous rodent activity, as revealed by continuous monitoring of the spontaneous usage of running activity wheels. Because such computers can commonly be obtained at little or no expense, and other commonly available materials and inexpensive parts can be used, these meters can be built quite economically. Construction of these meters requires no specialized electronics expertise, and their software requirements are simple. The computer interfaces are potentially of general interest, as they could also be used for monitoring a variety of events in a research setting.

  13. Fast, inexpensive, diffraction limited cylindrical microlenses

    International Nuclear Information System (INIS)

    Synder, J.J.; Reichert, P.

    1991-01-01

    We have developed a technique for fabricating fast, well corrected cylindrical microlenses. With this technique we have made a number of different microlenses with dimensions and focal lengths in the range of few hundred μm, and diffraction limited numerical apertures as high as 0.9. The microlenses are specifically designed for applications where they can increase the radiance or otherwise enhance the optical characteristics of laser diode light. The fabrication method we use is very versatile, and the microlenses produced this way would be very inexpensive in production quantities. 6 refs., 4 figs

  14. First results of systematic studies done with silicon photomultipliers

    International Nuclear Information System (INIS)

    Bosio, C.; Gentile, S.; Kuznetsova, E.; Meddi, F.

    2008-01-01

    Multicell avalanche photodiode structure operated in Geiger mode usually referred as silicon photomultiplier is a new intensively developing technology for photon detection. Insensitivity to magnetic fields, low operation voltage and small size make silicon photomultipliers very attractive for high-energy physics, astrophysics and medical applications. The presented results are obtained during the first steps taken in order to develop a setup and measurement procedures which allow to compare properties of diverse samples of silicon photomultipliers available on market. The response to low-intensity light was studied for silicon photomultipliers produced by CPTA (Russia), Hamamatsu (Japan), ITC-irst (Italy) and SensL (Ireland).

  15. Micro benchtop optics by bulk silicon micromachining

    Science.gov (United States)

    Lee, Abraham P.; Pocha, Michael D.; McConaghy, Charles F.; Deri, Robert J.

    2000-01-01

    Micromachining of bulk silicon utilizing the parallel etching characteristics of bulk silicon and integrating the parallel etch planes of silicon with silicon wafer bonding and impurity doping, enables the fabrication of on-chip optics with in situ aligned etched grooves for optical fibers, micro-lenses, photodiodes, and laser diodes. Other optical components that can be microfabricated and integrated include semi-transparent beam splitters, micro-optical scanners, pinholes, optical gratings, micro-optical filters, etc. Micromachining of bulk silicon utilizing the parallel etching characteristics thereof can be utilized to develop miniaturization of bio-instrumentation such as wavelength monitoring by fluorescence spectrometers, and other miniaturized optical systems such as Fabry-Perot interferometry for filtering of wavelengths, tunable cavity lasers, micro-holography modules, and wavelength splitters for optical communication systems.

  16. Characterization of new hexagonal large area Geiger Avalanche Photodiodes

    International Nuclear Information System (INIS)

    Boccone, V.; Aguilar, J.A.; Della Volpe, D.; Christov, A.; Montaruli, T.; Rameez, M.; Basili, A.

    2013-06-01

    Photomultipliers (PMTs) are the standard detector for construction of the current generation of imaging Atmospheric Cherenkov Telescopes (IACTs). Despite impressive improvements in QE and reliability in the last years, these devices suffer from the limitation of being unable to operate in the partially illuminated sky (during full or partial moon periods) as the excess light leads to a significant increase in the rate of ageing of the devices themselves and consequently limit the life of the camera. A viable alternative is the large area Geiger-mode avalanche photodiodes (G-APDs also known as Silicon Photomultipliers or SiPMs) that are commercially available from different producers in various types and dimensions. The sufficiency of the maturity of this technology for application to Cherenkov Astronomy has already been demonstrated by the FACT telescope. One of the camera designs under study for the 4 m Davies Cotton Telescope foresees the utilization of a large area G-APDs coupled to non imaging light concentrators. In collaboration with Hamamatsu and deriving from their current technology, we have designed a new hexagonal shaped large area G-APD HEX S12516 which when coupled to a Winston cone of 24 degrees cutting angle allows for a pixel angular resolution of 0.25 degrees for a f/D 1.4 telescope with a diameter of 4 m. The device, available in 2 different cell size configurations (50 μm and 100 μm), is divided into 4 different channels powered in common cathode mode. A temperature sensor was included for a better temperature evaluation in the characterization phase. The first 3 prototypes were fully characterized and the results are compared to the larger area devices commercially available such as the S10985-050C (2x2 array of 3x3 mm 2 G-APDs). The photo-detection efficiency is measured applying the Poisson statistics method using pulsed LED at 7 different wavelengths from 355 to 670 nm and for different bias over-voltages (V ov ). Optical crosstalk and

  17. Study of a PIN photodiode as an ionizing radiation detector for aerospace use; Estudo de um fotodiodo PIN como detector de radiação ionizante para uso aeroespacial

    Energy Technology Data Exchange (ETDEWEB)

    Nogueira, S.F.L.; Claro, L.H.; Santos, J.A.; Junior, J.R.; Federico, C.A., E-mail: msetephanireis@hotmail.com [Instituto de Estudos Avançados (IEAv), São José dos Campos, SP (Brazil). Divisão de Física Aplicada

    2017-07-01

    This work aims to study the use of the COTS PIN photodiode with an active area of 7.5 mm{sup 2} as an ionizing radiation detector. The tests were performed with a {sup 60}Co source and with low activity radioisotopic sources of {sup 60}Co, {sup 152}Eu, {sup 137}Cs and {sup 241}Am. The results were obtained by analyzing the current response generated by the photodiodes as a function of an attenuated dose rate in silicon in the range of 0.55 to 11.54 Gy / h.

  18. Discussion about photodiode architectures for space applications

    Science.gov (United States)

    Gravrand, O.; Destefanis, G.; Cervera, C.; Zanatta, J.-P.; Baier, N.; Ferron, A.; Boulade, O.

    2017-11-01

    configuration is a low flux application but the need for speed distinguishes it from other low flux applications as it usually requires a different ROIC architecture and a photodiode optimized for high response speed.

  19. Properties of the photodiode PiN as neutron detector

    International Nuclear Information System (INIS)

    Adamiec, G.; Iniguez, M.P.; Lorente, A.; Gallego, E.; Voytchev, M.

    2005-01-01

    The photodiode can be used to measure the ambient dose equivalent for an Am-Be source, as well placed in a paraffin sphere with LiF 6 converter as nude with a PE converter. The ratio between the counting rate and the ambient dose equivalent is linear in the two cases. The sensitivity of the diode with the converter 6 LiF is evaluated to 8.4 shocks by micro sievert by square centimeter of active surface of diode. The photodiode with the PE converter has a sensitivity lower of 2.1 shocks by micro sievert by square centimeter (for the Am-Be source) of active surface of diode. About the disadvantages, the disadvantage of photodiode inside the paraffin sphere is its size and weight; the disadvantage of the diode with the PE converter is its sensitivity to the orientation of the neutron flux and the necessity to calibrate for the source type. (N.C.)

  20. Lead contamination of inexpensive plastic jewelry

    Energy Technology Data Exchange (ETDEWEB)

    Yost, Jamie L. [Department of Chemistry, Ashland University, Ashland, Ohio (United States); Weidenhamer, Jeffrey D. [Department of Chemistry, Ashland University, Ashland, Ohio (United States)], E-mail: jweiden@ashland.edu

    2008-04-15

    The neurological hazards of lead to children are well-known. As a result of recent documented cases of lead poisoning, regulatory attention in the United States has focused on the lead content of children's metal jewelry. By contrast, little is known about the possible hazards of plastic jewelry items. The objective of this study was to determine whether inexpensive plastic jewelry is a possible source of toxic lead for children. Samples of more than 100 inexpensive plastic jewelry items were analyzed for lead content. Beads were screened by soaking in 1 M nitric acid. Nine items found to release more than 30 {mu}g of lead per bead were further tested for accessible lead, and scrapings of the bead coatings were analyzed for total lead content. The maximum accessible lead found was 49 {mu}g per bead, which is below the current US Consumer Product Safety Commission limit of 175 {mu}g. However, when the number of beads in each item was taken into account, six of the nine leaded samples contained more than 175 {mu}g accessible lead per item. The lead in these items appears to be associated with lead-based paints used to produce glossy coatings on imitation pearls and similar items. Coatings obtained by scraping individual beads contained 3.5-23% lead, which far exceeds the US regulatory limit of 0.06% lead in paints on items intended for children. Our results demonstrate that plastic jewelry items merit the attention of public health and consumer protection agencies seeking to limit the exposure of children to lead.

  1. Lead contamination of inexpensive plastic jewelry

    International Nuclear Information System (INIS)

    Yost, Jamie L.; Weidenhamer, Jeffrey D.

    2008-01-01

    The neurological hazards of lead to children are well-known. As a result of recent documented cases of lead poisoning, regulatory attention in the United States has focused on the lead content of children's metal jewelry. By contrast, little is known about the possible hazards of plastic jewelry items. The objective of this study was to determine whether inexpensive plastic jewelry is a possible source of toxic lead for children. Samples of more than 100 inexpensive plastic jewelry items were analyzed for lead content. Beads were screened by soaking in 1 M nitric acid. Nine items found to release more than 30 μg of lead per bead were further tested for accessible lead, and scrapings of the bead coatings were analyzed for total lead content. The maximum accessible lead found was 49 μg per bead, which is below the current US Consumer Product Safety Commission limit of 175 μg. However, when the number of beads in each item was taken into account, six of the nine leaded samples contained more than 175 μg accessible lead per item. The lead in these items appears to be associated with lead-based paints used to produce glossy coatings on imitation pearls and similar items. Coatings obtained by scraping individual beads contained 3.5-23% lead, which far exceeds the US regulatory limit of 0.06% lead in paints on items intended for children. Our results demonstrate that plastic jewelry items merit the attention of public health and consumer protection agencies seeking to limit the exposure of children to lead

  2. Substrate and Passivation Techniques for Flexible Amorphous Silicon-Based X-ray Detectors.

    Science.gov (United States)

    Marrs, Michael A; Raupp, Gregory B

    2016-07-26

    Flexible active matrix display technology has been adapted to create new flexible photo-sensing electronic devices, including flexible X-ray detectors. Monolithic integration of amorphous silicon (a-Si) PIN photodiodes on a flexible substrate poses significant challenges associated with the intrinsic film stress of amorphous silicon. This paper examines how altering device structuring and diode passivation layers can greatly improve the electrical performance and the mechanical reliability of the device, thereby eliminating one of the major weaknesses of a-Si PIN diodes in comparison to alternative photodetector technology, such as organic bulk heterojunction photodiodes and amorphous selenium. A dark current of 0.5 pA/mm² and photodiode quantum efficiency of 74% are possible with a pixelated diode structure with a silicon nitride/SU-8 bilayer passivation structure on a 20 µm-thick polyimide substrate.

  3. A Discrete Component Low-Noise Preamplifier Readout for a Linear (1x16) SiC Photodiode Array

    Science.gov (United States)

    Kahle, Duncan; Aslam, Shahid; Herrero, Frederico A.; Waczynski, Augustyn

    2016-01-01

    A compact, low-noise and inexpensive preamplifier circuit has been designed and fabricated to optimally readout a common cathode (1x16) channel 4H-SiC Schottky photodiode array for use in ultraviolet experiments. The readout uses an operational amplifier with 10 pF capacitor in the feedback loop in parallel with a low leakage switch for each of the channels. This circuit configuration allows for reiterative sample, integrate and reset. A sampling technique is given to remove Johnson noise, enabling a femtoampere level readout noise performance. Commercial-off-the-shelf acquisition electronics are used to digitize the preamplifier analogue signals. The data logging acquisition electronics has a different integration circuit, which allows the bandwidth and gain to be independently adjusted. Using this readout, photoresponse measurements across the array between spectral wavelengths 200 nm and 370 nm are made to establish the array pixels external quantum efficiency, current responsivity and noise equivalent power.

  4. Development of an X-ray detector using photodiodes; Desarrollo de un detector de rayos X usando fotodiodos

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez G, J.; Azorin V, J. C.; Sosa A, M. A.; Ceron, P., E-mail: gonzalezgj2012@licifug.ugto.mx [Universidad de Guanajuato, Division de Ciencias e Ingenierias, Loma del Bosque No. 103, Col. Lomas del Campestre, 37150 Leon, Guanajuato (Mexico)

    2016-10-15

    Currently the radiation detectors for medical applications are very high value in the market and are difficult to access as training material. In the Sciences and Engineering Division of the Guanajuato University (Mexico) investigations are carried out related to ionizing radiations, especially with X-rays. To overcome the lack of materials has had to resort to borrowing equipment from other institutions, so its use and availability are intermittent. For these reasons is proposed to design and implement an X-ray detector for the use of the work group and the University. This work aims to build an X-ray semiconductor detector using inexpensive and affordable materials, is also proposed the use of a photodiode sensor and an Arduino analog-digital card and a LCD display showing the data. (Author)

  5. A discrete component low-noise preamplifier readout for a linear (1×16) SiC photodiode array

    Energy Technology Data Exchange (ETDEWEB)

    Kahle, Duncan [NASA, Goddard Space Flight Center, Detector Systems Branch, Greenbelt, MD 20771 (United States); Aslam, Shahid, E-mail: shahid.aslam-1@nasa.gov [NASA, Goddard Space Flight Center, Planetary Systems Laboratory, Greenbelt, MD 20771 (United States); Herrero, Federico A.; Waczynski, Augustyn [NASA, Goddard Space Flight Center, Detector Systems Branch, Greenbelt, MD 20771 (United States)

    2016-09-11

    A compact, low-noise and inexpensive preamplifier circuit has been designed and fabricated to optimally readout a common cathode (1×16) channel 4H-SiC Schottky photodiode array for use in ultraviolet experiments. The readout uses an operational amplifier with 10 pF capacitor in the feedback loop in parallel with a low leakage switch for each of the channels. This circuit configuration allows for reiterative sample, integrate and reset. A sampling technique is given to remove Johnson noise, enabling a femtoampere level readout noise performance. Commercial-off-the-shelf acquisition electronics are used to digitize the preamplifier analog signals. The data logging acquisition electronics has a different integration circuit, which allows the bandwidth and gain to be independently adjusted. Using this readout, photoresponse measurements across the array between spectral wavelengths 200 nm and 370 nm are made to establish the array pixels external quantum efficiency, current responsivity and noise equivalent power.

  6. Visible light photodiodes and photovoltages from detonation nanodiamonds

    Czech Academy of Sciences Publication Activity Database

    Rezek, Bohuslav; Stehlík, Štěpán; Kromka, Alexander; Arnault, J.-C.; Weis, M.; Jakabovič, J.

    2016-01-01

    Roč. 1, č. 14 (2016), s. 971-975 ISSN 2059-8521 R&D Projects: GA ČR GA15-01809S Institutional support: RVO:68378271 Keywords : nanodiamond * photodiode Subject RIV: BM - Solid Matter Physics ; Magnetism

  7. Optical fibers and avalanche photodiodes for scintillator counters

    International Nuclear Information System (INIS)

    Borenstein, S.R.; Palmer, R.B.; Strand, R.C.

    1980-01-01

    Fine hodoscopes can be made of new scintillating optical fibers and one half inch end-on PMT's. An avalanche photodiode with small size and immunity to magnetic fields remains as a tempting new device to be proven as a photodetector for the fibers

  8. Silicone metalization

    Energy Technology Data Exchange (ETDEWEB)

    Maghribi, Mariam N. (Livermore, CA); Krulevitch, Peter (Pleasanton, CA); Hamilton, Julie (Tracy, CA)

    2008-12-09

    A system for providing metal features on silicone comprising providing a silicone layer on a matrix and providing a metal layer on the silicone layer. An electronic apparatus can be produced by the system. The electronic apparatus comprises a silicone body and metal features on the silicone body that provide an electronic device.

  9. Silicon photonic dynamic optical channel leveler with external feedback loop.

    Science.gov (United States)

    Doylend, J K; Jessop, P E; Knights, A P

    2010-06-21

    We demonstrate a dynamic optical channel leveler composed of a variable optical attenuator (VOA) integrated monolithically with a defect-mediated photodiode in a silicon photonic waveguide device. An external feedback loop mimics an analog circuit such that the photodiode directly controls the VOA to provide blind channel leveling within +/-1 dB across a 7-10 dB dynamic range for wavelengths from 1530 nm to 1570 nm. The device consumes approximately 50 mW electrical power and occupies a 6 mm x 0.1 mm footprint per channel. Dynamic leveling is accomplished without tapping optical power from the output path to the photodiode and thus the loss penalty is minimized.

  10. Index of Free and Inexpensive Food and Nutrition Information Materials.

    Science.gov (United States)

    Gordon, Kathleen, Comp.; And Others

    This annotated index contains approximately 2,000 free or inexpensive pamphlets or brochures about food and nutrition. The prime criterion for inclusion of materials was that they be easily available and inexpensive; the cut-off cost was set at $3.00. The majority of materials listed were produced in either Canada or the United States. These…

  11. Silicon nanowire transistors

    CERN Document Server

    Bindal, Ahmet

    2016-01-01

    This book describes the n and p-channel Silicon Nanowire Transistor (SNT) designs with single and dual-work functions, emphasizing low static and dynamic power consumption. The authors describe a process flow for fabrication and generate SPICE models for building various digital and analog circuits. These include an SRAM, a baseband spread spectrum transmitter, a neuron cell and a Field Programmable Gate Array (FPGA) platform in the digital domain, as well as high bandwidth single-stage and operational amplifiers, RF communication circuits in the analog domain, in order to show this technology’s true potential for the next generation VLSI. Describes Silicon Nanowire (SNW) Transistors, as vertically constructed MOS n and p-channel transistors, with low static and dynamic power consumption and small layout footprint; Targets System-on-Chip (SoC) design, supporting very high transistor count (ULSI), minimal power consumption requiring inexpensive substrates for packaging; Enables fabrication of different types...

  12. Radiated power measurement with AXUV photodiodes in EAST tokamak

    International Nuclear Information System (INIS)

    Duan Yanmin; Hu Liqun; Du Wei; Mao Songtao; Chen Kaiyun; Zhang Jizhong

    2013-01-01

    The fast bolometer diagnostic system for absolute radiated power measurement on EAST tokamak is introduced, which is based on the absolute extreme ultraviolet (AXUV) photodiodes. The relative calibration of AXUV detectors is carried out using X-ray tube and standard luminance source in order to evaluate the sensitivity degradation caused by cumulative radiation damage during experiments. The calibration result shows a 23% sensitivity decrease in the X-ray range for the detector suffering ∼27000 discharges, but the sensitivity for the visible light changes little. The radiated power measured by AXUV photodiodes is compared with that measured by resistive bolometer. The total radiated power in main plasma deduced from AXUV detector is lower a factor of 1∼4 than that deduced from resistive bolometer. Some typical measurement results are also shown in this article. (author)

  13. Response of commercial photodiodes for application in alpha spectrometry

    International Nuclear Information System (INIS)

    Ferreira Filho, Alfredo Lopes

    1998-06-01

    The use of semiconductor detector for ionizing radiations spectrometry and dosimetry has been growing in the last years due to its characteristics of fast response, good efficiency for unit of volume and excellent resolution. Since the working principle of a semiconductor detector is identical to that of the semiconductor junctions of commercial electronic devices, a study was carried out on the PIN-photodiodes response, aiming at set up an alpha spectrometry system of low cost and easy acquisition. The tested components have the following characteristics: active area varying between 13.2 and 25 mm 2 , window of thickness equal or lower than 57 mg/cm 2 , depletion area with depth ranging from 10 to 300 μm and junction capacitance of 16 to 20 pF.Am-241, Cm-244, U-233 and Np-237 alpha sources produced by electrodeposition were used to evaluate the response of the devices as a function of the radiation energy. The results have shown a linear response of the photodiodes with the incident alpha particle energy. The resolution varied from 1.6% to 0.45% and the better detection efficiency found was about 7.2. The low cost of the photodiodes and the excellent results obtained at room temperature make such components very attractive for teaching purposes for environmental monitoring. (author)

  14. Novel micropixel avalanche photodiodes (MAPD) with super high pixel density

    International Nuclear Information System (INIS)

    Anfimov, N.; Chirikov-Zorin, I.; Dovlatov, A.; Gavrishchuk, O.; Guskov, A.; Khovanskiy, N.; Krumshtein, Z.; Leitner, R.; Meshcheryakov, G.; Nagaytsev, A.; Olchevski, A.; Rezinko, T.; Sadovskiy, A.; Sadygov, Z.; Savin, I.; Tchalyshev, V.; Tyapkin, I.; Yarygin, G.; Zerrouk, F.

    2011-01-01

    In many detectors based on scintillators the photomultiplier tubes (PMTs) are used as photodetectors. At present photodiodes are finding wide application. Solid state photodetectors allow operation in strong magnetic fields that are often present in applications, e.g. some calorimeters operating near magnets, combined PET and MRT, etc. The photon detection efficiency (PDE) of photodiodes may reach values a few times higher than that of PMTs. Also, they are rigid, compact and have relatively low operating voltage. In the last few years Micropixel Avalanche PhotoDiodes (MAPD) have been developed and started to be used. The MAPD combines a lot of advantages of semiconductor photodetectors and has a high gain, which is close to that of the PMT. Yet, they have some disadvantages, and one of them is a limited dynamic range that corresponds to a total number of pixels. The novel deep microwell MAPD with high pixel density produced by the Zecotek Company partially avoids this disadvantage. In this paper characteristics of these photodetectors are presented in comparison with the PMT characteristics. The results refer to measurements of the gain, PDE, cross-talks, photon counting and applications: beam test results of two different 'Shashlyk' EM calorimeters for COMPASS (CERN) and NICA-MPD (JINR) with the MAPD readout and a possibility of using the MAPD in PET.

  15. Amplifiers dedicated for large area SiC photodiodes

    Science.gov (United States)

    Doroz, P.; Duk, M.; Korwin-Pawlowski, M. L.; Borecki, M.

    2016-09-01

    Large area SiC photodiodes find applications in optoelectronic sensors working at special conditions. These conditions include detection of UV radiation in harsh environment. Moreover, the mentioned sensors have to be selective and resistant to unwanted signals. For this purpose, the modulation of light at source unit and the rejection of constant current and low frequency component of signal at detector unit are used. The popular frequency used for modulation in such sensor is 1kHz. The large area photodiodes are characterized by a large capacitance and low shunt resistance that varies with polarization of the photodiode and can significantly modify the conditions of signal pre-amplification. In this paper two pre-amplifiers topology are analyzed: the transimpedance amplifier and the non-inverting voltage to voltage amplifier with negative feedback. The feedback loops of both pre-amplifiers are equipped with elements used for initial constant current and low frequency signals rejections. Both circuits are analyzed and compared using simulation and experimental approaches.

  16. Novel micropixel avalanche photodiodes (MAPD) with superhigh pixel density

    International Nuclear Information System (INIS)

    Anfimov, N.; Chirikov-Zorin, I.; Dovlatov, A.

    2010-01-01

    In many detectors based on scintillators the photomultiplier tubes (PMTs) are used as photodetectors. At present photodiodes are finding wide application. Solid state photodetectors allow operation in strong magnetic fields that are often present in applications, e.g., some calorimeters operating near magnets, combined PET and MRT, etc. The photon detection efficiency (PDE) of photodiodes may reach values a few times higher than that of PMTs. Also, they are rigid, compact and have relatively low operating voltage. In the last few years Micropixel Avalanche PhotoDiodes (MAPDs) have been developed and started to be used. The MAPD combines a lot of advantages of semiconductor photodetectors and has a high gain, which is close to that of the PMT. Yet, they have some disadvantages, and one of them is a limited dynamic range that corresponds to a total number of pixels. The novel deep microwell MAPD with high pixel density produced by Zecotek Company partially avoids this disadvantage. In this paper characteristics of these photodetectors are presented in comparison with the PMT characteristics. The results refer to measurements of the gain, PDE, cross-talks, photon counting and applications: beam test results of two different 'Shashlyk' EM calorimeters for COMPASS (CERN) and NICA-MPD (JINR) with the MAPD readout and a possibility of using the MAPD in PET

  17. A new and inexpensive pyranometer for the visible spectral range.

    Science.gov (United States)

    Martínez, Miguel A; Andújar, José M; Enrique, Juan M

    2009-01-01

    This paper presents the design, construction and testing of a new photodiode-based pyranometer for the visible spectral range (approx. 400 to 750 nm), whose principal characteristics are: accuracy, ease of connection, immunity to noise, remote programming and operation, interior temperature regulation, cosine error minimisation and all this at a very low cost, tens of times lower than that of commercial thermopile-based devices. This new photodiode-based pyranometer overcomes traditional problems in this type of device and offers similar characteristics to those of thermopile-based pyranometers and, therefore, can be used in any installation where reliable measurement of solar irradiance is necessary, especially in those where cost is a deciding factor in the choice of a meter. This new pyranometer has been registered in the Spanish Patent and Trademark Office under the number P200703162.

  18. A New and Inexpensive Pyranometer for the Visible Spectral Range

    Directory of Open Access Journals (Sweden)

    Miguel A. Martínez

    2009-06-01

    Full Text Available This paper presents the design, construction and testing of a new photodiode-based pyranometer for the visible spectral range (approx. 400 to 750 nm, whose principal characteristics are: accuracy, ease of connection, immunity to noise, remote programming and operation, interior temperature regulation, cosine error minimisation and all this at a very low cost, tens of times lower than that of commercial thermopile-based devices. This new photodiode-based pyranometer overcomes traditional problems in this type of device and offers similar characteristics to those of thermopile-based pyranometers and, therefore, can be used in any installation where reliable measurement of solar irradiance is necessary, especially in those where cost is a deciding factor in the choice of a meter. This new pyranometer has been registered in the Spanish Patent and Trademark Office under the number P200703162.

  19. Silicon CMOS photonics platform for enabling high-speed DQPSK transceivers

    NARCIS (Netherlands)

    Sanchis, P.; Aamer, M.; Brimont, A.; Gutierrez, A.M.; Sotiropoulos, N.; Waardt, de H.; Thomson, D.J.; Gardes, F.Y.; Reed, G.T.; Ribaud, K.; Grosse, P.; Hartmann, J. M.; Fedeli, J.M.; Marris-Morini, D.; Cassan, E.; Vivien, L.; Vermeulen, D.; Roelkens, G.; Hakansson, A.

    2013-01-01

    In this work we review the results obtained under the framework of FP7-HELIOS project for integrated DQPSK transceivers in silicon photonics. A differential DQPSK receiver with balanced zero biased Germanium photodiodes has been demonstrated at 10Gbit/s with an error floor around 10-15. Furthermore,

  20. Detection of charged particles through a photodiode: design and analysis; Deteccion de particulas cargadas mediante un fotodiodo: diseno y analisis

    Energy Technology Data Exchange (ETDEWEB)

    Angoli, A.; Quirino, L.L.; Hernandez, V.M.; Lopez del R, H.; Mireles, F.; Davila, J.I.; Rios, C.; Pinedo, J.L. [UAEN, UAZ, 98000 Zacatecas (Mexico)]. e-mail: toono4@hotmail.com

    2006-07-01

    This project develops and construct an charge particle detector mean a pin photodiode array, design and analysis using a silicon pin Fotodiodo that generally is used to detect visible light, its good efficiency, size compact and reduced cost specifically allows to its use in the radiation monitoring and alpha particle detection. Here, so much, appears the design of the system of detection like its characterization for alpha particles where one is reported as alpha energy resolution and detection efficiency. The equipment used in the development of work consists of alpha particle a triple source composed of Am-241, Pu-239 and Cm-244 with 5,55 KBq as total activity, Maestro 32 software made by ORTEC, a multi-channel card Triumph from ORTEC and one low activity electroplated uranium sample. (Author)

  1. Evaluation of BPW-34 photodiode answer for 10 MeV electron dosimetry

    International Nuclear Information System (INIS)

    Khoury, H.J.; Melo, F.A.; Hazin, C.A.

    1992-01-01

    The viability of commercial photodiodes used for dosimetry of high energy electron beams was studied. The measures were made in a linear accelerators of 10 MeV, using the BPW-34 photodiode. The average energy of electrons on phantom surface and their average range were determined with the photodiode, and the results were compared with the obtained with a ionization chamber of parallel plate. (C.G.C.)

  2. Silicon Photo-Multiplier Radiation Hardness Tests with a White Neutron Beam

    International Nuclear Information System (INIS)

    Montanari, A.; Tosi, N.; Pietropaolo, A.; Andreotti, M.; Baldini, W.; Calabrese, R.; Cibinetto, G.; Luppi, E.; Cotta Ramusino, A.; Malaguti, R.; Santoro, V.; Tellarini, G.; Tomassetti, L.; De Donato, C.; Reali, E.

    2013-06-01

    We report radiation hardness tests performed, with a white neutron beam, at the Geel Electron Linear Accelerator in Belgium on silicon Photo-Multipliers. These are semiconductor photon detectors made of a square matrix of Geiger-Mode Avalanche photo-diodes on a silicon substrate. Several samples from different manufacturers have been irradiated integrating up to about 6.2 x 10 9 1-MeV-equivalent neutrons per cm 2 . (authors)

  3. Exploring "Extreme" Physics with an Inexpensive Plastic Toy Popper

    Science.gov (United States)

    Lapp, David R.

    2008-01-01

    This article describes an activity that can be performed with an inexpensive plastic toy popper. The activity builds skill at analysing motion and results in the calculation of a surprisingly extreme acceleration. (Contains 1 figure.)

  4. Single-photon semiconductor photodiodes for distributed optical fiber sensors: state of the art and perspectives

    Science.gov (United States)

    Ripamonti, Giancarlo; Lacaita, Andrea L.

    1993-03-01

    The extreme sensitivity and time resolution of Geiger-mode avalanche photodiodes (GM- APDs) have already been exploited for optical time domain reflectometry (OTDR). Better than 1 cm spatial resolution in Rayleigh scattering detection was demonstrated. Distributed and quasi-distributed optical fiber sensors can take advantage of the capabilities of GM-APDs. Extensive studies have recently disclosed the main characteristics and limitations of silicon devices, both commercially available and developmental. In this paper we report an analysis of the performance of these detectors. The main characteristics of GM-APDs of interest for distributed optical fiber sensors are briefly reviewed. Command electronics (active quenching) is then introduced. The detector timing performance sets the maximum spatial resolution in experiments employing OTDR techniques. We highlight that the achievable time resolution depends on the physics of the avalanche spreading over the device area. On the basis of these results, trade-off between the important parameters (quantum efficiency, time resolution, background noise, and afterpulsing effects) is considered. Finally, we show first results on Germanium devices, capable of single photon sensitivity at 1.3 and 1.5 micrometers with sub- nanosecond time resolution.

  5. Single photon detection in a waveguide-coupled Ge-on-Si lateral avalanche photodiode.

    Science.gov (United States)

    Martinez, Nicholas J D; Gehl, Michael; Derose, Christopher T; Starbuck, Andrew L; Pomerene, Andrew T; Lentine, Anthony L; Trotter, Douglas C; Davids, Paul S

    2017-07-10

    We examine gated-Geiger mode operation of an integrated waveguide-coupled Ge-on-Si lateral avalanche photodiode (APD) and demonstrate single photon detection at low dark count for this mode of operation. Our integrated waveguide-coupled APD is fabricated using a selective epitaxial Ge-on-Si growth process resulting in a separate absorption and charge multiplication (SACM) design compatible with our silicon photonics platform. Single photon detection efficiency and dark count rate is measured as a function of temperature in order to understand and optimize performance characteristics in this device. We report single photon detection of 5.27% at 1310 nm and a dark count rate of 534 kHz at 80 K for a Ge-on-Si single photon avalanche diode. Dark count rate is the lowest for a Ge-on-Si single photon detector in this range of temperatures while maintaining competitive detection efficiency. A jitter of 105 ps was measured for this device.

  6. Hybrid AlGaN-SiC Avalanche Photodiode for Deep-UV Photon Detection

    Science.gov (United States)

    Aslam, Shahid; Herrero, Federico A.; Sigwarth, John; Goldsman, Neil; Akturk, Akin

    2010-01-01

    The proposed device is capable of counting ultraviolet (UV) photons, is compatible for inclusion into space instruments, and has applications as deep- UV detectors for calibration systems, curing systems, and crack detection. The device is based on a Separate Absorption and Charge Multiplication (SACM) structure. It is based on aluminum gallium nitride (AlGaN) absorber on a silicon carbide APD (avalanche photodiode). The AlGaN layer absorbs incident UV photons and injects photogenerated carriers into an underlying SiC APD that is operated in Geiger mode and provides current multiplication via avalanche breakdown. The solid-state detector is capable of sensing 100-to-365-nanometer wavelength radiation at a flux level as low as 6 photons/pixel/s. Advantages include, visible-light blindness, operation in harsh environments (e.g., high temperatures), deep-UV detection response, high gain, and Geiger mode operation at low voltage. Furthermore, the device can also be designed in array formats, e.g., linear arrays or 2D arrays (micropixels inside a superpixel).

  7. Initial characterization of a BGO-photodiode detector for high resolution positron emission tomography

    International Nuclear Information System (INIS)

    Derenzo, S.E.

    1983-11-01

    Spatial resolution in positron emission tomography is currently limited by the resolution of the detectors. This work presents the initial characterization of a detector design using small bismuth germanate (BGO) crystals individually coupled to silicon photodiodes (SPDs) for crystal identification, and coupled in groups to phototubes (PMTs) for coincidence timing. A 3 mm x 3 mm x 3 mm BGO crystal coupled only to an SPD can achieve a 511 keV photopeak resolution of 8.7% FWHM at -150 0 C, using a pulse peaking time of 10 μs. When two 3 mm x 3 mm x 15 mm BGO crystals are coupled individually to SPDs and also coupled to a common 14 mm diam PMT, the SPDs detect the 511 keV photopeak with a resolution of 30% FWHM at -76 0 C. In coincidence with an opposing 3 mm wide BGO crystal, the SPDs are able to identify the crystal of interaction with good signal-to-noise ratio, and the detector pair resolution is 2 mm FWHM. 32 references, 7 figures, 3 tables

  8. Design and Performance of a Pinned Photodiode CMOS Image Sensor Using Reverse Substrate Bias.

    Science.gov (United States)

    Stefanov, Konstantin D; Clarke, Andrew S; Ivory, James; Holland, Andrew D

    2018-01-03

    A new pinned photodiode (PPD) CMOS image sensor with reverse biased p-type substrate has been developed and characterized. The sensor uses traditional PPDs with one additional deep implantation step to suppress the parasitic reverse currents, and can be fully depleted. The first prototypes have been manufactured on an 18 µm thick, 1000 Ω·cm epitaxial silicon wafers using 180 nm PPD image sensor process. Both front-side illuminated (FSI) and back-side illuminated (BSI) devices were manufactured in collaboration with Teledyne e2v. The characterization results from a number of arrays of 10 µm and 5.4 µm PPD pixels, with different shape, the size and the depth of the new implant are in good agreement with device simulations. The new pixels could be reverse-biased without parasitic leakage currents well beyond full depletion, and demonstrate nearly identical optical response to the reference non-modified pixels. The observed excessive charge sharing in some pixel variants is shown to not be a limiting factor in operation. This development promises to realize monolithic PPD CIS with large depleted thickness and correspondingly high quantum efficiency at near-infrared and soft X-ray wavelengths.

  9. Sheet resistance effects in mercury cadmium telluride implanted photodiodes

    International Nuclear Information System (INIS)

    Fiorito, G.; Gasparrini, G.; Svelto, F.

    1977-01-01

    The frequency response of Hg + implanted Hgsub(1-x)Cdsub(x)Te photodiodes is discussed. This analysis, evaluating both the response to fast laser pulses and the 3 dB rolloff of the diode shot-noise spectrum, showed the necessity of adopting a distributed equivalent circuit model taking into account the implanted layer sheet resistance. Frequency behaviour, in fact, proved not to match a simple p-n junction model based on a lumped standard equivalent circuit. On this basis apparent anomalies previously reported can be explained, and useful suggestions can be obtained for design and fabrication of fast detectors. (author)

  10. Silicon detectors

    International Nuclear Information System (INIS)

    Klanner, R.

    1984-08-01

    The status and recent progress of silicon detectors for high energy physics is reviewed. Emphasis is put on detectors with high spatial resolution and the use of silicon detectors in calorimeters. (orig.)

  11. Increasing the realism of a laparoscopic box trainer: a simple, inexpensive method.

    Science.gov (United States)

    Hull, Louise; Kassab, Eva; Arora, Sonal; Kneebone, Roger

    2010-01-01

    Simulation-based training in medical education is increasing. Realism is an integral element of creating an engaging, effective training environment. Although physical trainers offer a low-cost alternative to expensive virtual reality (VR) simulators, many lack in realism. The aim of this research was to enhance the realism of a laparoscopic box trainer by using a simple, inexpensive method. Digital images of the abdominal cavity were captured from a VR simulator. The images were printed onto a laminated card that lined the bottom and sides of the box-trainer cavity. The standard black neoprene material that encloses the abdominal cavity was replaced with a skin-colored silicon model. The realism of the modified box trainer was assessed by surgeons, using quantitative and qualitative methodologies. Results suggest that the modified box trainer was more realistic than a standard box trainer alone. Incorporating this technique in the training of laparoscopic skills is an inexpensive means of emulating surgical reality that may enhance the engagement of the learner in simulation.

  12. Physical and electrical bandwidths of integrated photodiodes in standard CMOS technology

    NARCIS (Netherlands)

    Radovanovic, S.; Annema, Anne J.; Nauta, Bram

    2003-01-01

    The influence of different geometries (layouts) and structures of high-speed photodiodes in fully standard 0.18 μm CMOS technology on their intrinsic (physical) and electrical bandwidths is analyzed. Three photodiode structures are studied: nwell/p-substrate, p+/nwell/p-substrate and p+/nwell. The

  13. Performance Analysis of Si-Based Ultra-Shallow Junction Photodiodes for UV Radiation Detection

    NARCIS (Netherlands)

    Shi, L.

    2013-01-01

    This thesis presents a performance investigation of newly-developed ultra-shallow junction photodiodes (PureB-diodes) for ultraviolet (UV) radiation detection. The photodiodes are fabricated by pure boron chemical vapor deposition (PureB CVD) technology, which can provide nanometer-thin boron

  14. Dephosphorization of Levitated Silicon-Iron Droplets for Production of Solar-Grade Silicon

    Science.gov (United States)

    Le, Katherine; Yang, Yindong; Barati, Mansoor; McLean, Alexander

    2018-05-01

    The treatment of relatively inexpensive silicon-iron alloys is a potential refining route in order to generate solar-grade silicon. Phosphorus is one of the more difficult impurity elements to remove by conventional processing. In this study, electromagnetic levitation was used to investigate phosphorus behavior in silicon-iron alloy droplets exposed to H2-Ar gas mixtures under various experimental conditions including, refining time, temperature (1723 K to 1993 K), gas flow rate, iron content, and initial phosphorus concentration in the alloy. Thermodynamic modeling of the dephosphorization reaction permitted prediction of the various gaseous products and indicated that diatomic phosphorus is the dominant species formed.

  15. A photodiode based on PbS nanocrystallites for FYTRONIX solar panel automatic tracking controller

    Science.gov (United States)

    Wageh, S.; Farooq, W. A.; Tataroğlu, A.; Dere, A.; Al-Sehemi, Abdullah G.; Al-Ghamdi, Ahmed A.; Yakuphanoglu, F.

    2017-12-01

    The structural, optical and photoelectrical properties of the fabricated Al/PbS/p-Si/Al photodiode based on PbS nanocrystallites were investigated. The PbS nanocrystallites were characterized by X-ray diffraction (XRD), UV-VIS-NIR, Infrared and Raman spectroscopy. The XRD diffraction peaks show that the prepared PbS nanostructure is in high crystalline state. Various electrical parameters of the prepared photodiode were analyzed from the electrical characteristics based on I-V and C-V-G. The photodiode has a high rectification ratio of 5.85×104 at dark and ±4 V. Moreover, The photocurrent results indicate a strong photovoltaic behavior. The frequency dependence of capacitance and conductance characteristics was attributed to depletion region behavior of the photodiode. The diode was used to control solar panel power automatic tracking controller in dual axis. The fabricated photodiode works as a photosensor to control Solar tracking systems.

  16. Bio-inspired nano-photodiode for Low Light, High Resolution and crosstalk-free CMOS image sensing

    KAUST Repository

    Saffih, Faycal; Fitzpatrick, Nathaniel N.; Mohammad, Mohammad Ali; Evoy, S.; Cui, Bo

    2011-01-01

    photodiode morphology. The proposed bio-inspired nanorod photodiode puts the depletion region length on the path of the incident photon instead of on its width, as the case is with the planar photodiodes. The depletion region has a revolving volume

  17. Suppression of irradiation effects in gold-doped silicon detectors

    International Nuclear Information System (INIS)

    McPherson, M.; Sloan, T.; Jones, B.K.

    1997-01-01

    Two sets of silicon detectors were irradiated with 1 MeV neutrons to different fluences and then characterized. The first batch were ordinary p-i-n photodiodes fabricated from high-resistivity (400 Ω cm) silicon, while the second batch were gold-doped powder diodes fabricated from silicon material initially of low resistivity (20 Ω cm). The increase in reverse leakage current after irradiation was found to be more in the former case than in the latter. The fluence dependence of the capacitance was much more pronounced in the p-i-n diodes than in the gold-doped diodes. Furthermore, photo current generation by optical means was less in the gold doped devices. All these results suggest that gold doping in silicon somewhat suppresses the effects of neutron irradiation. (author)

  18. Performance of silicon PIN photodiodes at low temperatures and in high magnetic fields

    Czech Academy of Sciences Publication Activity Database

    Wauters, F.; Kraeva, I.S.; Tandecki, M.; Traykov, E.; Van Gorp, S.; Zákoucký, Dalibor; Severijns, N.

    2009-01-01

    Roč. 604, č. 3 (2009), s. 563-567 ISSN 0168-9002 Institutional research plan: CEZ:AV0Z10480505 Keywords : PIN-diode * beta-particle detection * Magnetic field Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.317, year: 2009

  19. A 500-MHz x-ray counting system with a silicon avalanche photodiode

    International Nuclear Information System (INIS)

    Kishimoto, Shunji

    2009-01-01

    In the present measurements using a Si-APD X-ray detector and a 500-MHz counting system, the maximum output rate of 3.3x10 8 s -1 was achieved for 8-keV X-rays in beamline BL-14A of the Photon Factory. A small Si-APD of 4-pF electric capacity was used as the detector device in order to output a pulse of a width shorter than 2 ns on the baseline. For processing the fast pulses, the discriminator and the scaler having a throughput of >500 MHz, were prepared. Since the acceleration frequency at the PF ring was 500.1 MHz and the empty-bunch spacing was 12/312 bunches per circumference, the expected maximum rate was 4.8x10 8s-1 according to the counting model for a pulsed photon source. The reason why the present system did not reach the expected value was the baseline shift at the amplifier outputs. The rise of +0.2 V was observed at a discriminator output of 3.3x10 8 s -1 , while the pulse height was lower than 0.2 V. The baseline shift was caused by an AC coupling circuit in the amplifier. If a DC coupling circuit can be used for the amplifier, instead of the AC coupling circuit, or an active adjustment to compensate the baseline shift is installed, the counting system will show an ideal response. Although the present system including NIM modules was not so compact, we would like to develop a new fast-counting circuit for a Si-APD array detector of more than 100 channels of small pixels, in near future. (author)

  20. The silicon vertex tracker for star and future applications of silicon drift detectors

    International Nuclear Information System (INIS)

    Bellwied, Rene

    2001-01-01

    The Silicon Vertex Tracker (SVT) for the STAR experiment at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory has recently been completed and installed. First data were taken in July 2001. The SVT is based on a novel semi-conductor technology called Silicon Drift Detectors. 216 large area (6 by 6 cm) Silicon wafers were employed to build a three barrel device capable of vertexing and tracking in a high occupancy environment. Its intrinsic radiation hardness, its operation at room temperature and its excellent position resolution (better than 20 micron) in two dimensions with a one dimensional detector readout, make this technology very robust and inexpensive and thus a viable alternative to CCD, Silicon pixel and Silicon strip detectors in a variety of applications from fundamental research in high-energy and nuclear physics to astrophysics to medical imaging. I will describe the development that led to the STAR-SVT, its performance and possible applications for the near future

  1. Teaching Insect Retinal Physiology with Newly Designed, Inexpensive Micromanipulators

    Science.gov (United States)

    Krans, Jacob; Gilbert, Cole; Hoy, Ron

    2006-01-01

    In this article, we detail how to produce two inexpensive micromanipulators that offer high precision (approximately 25 micrometers) along a single axis of movement. The more expensive of the designs provides improved versatility along multiple axes. Both manipulators offer substantial savings over commercially available micromanipulators with…

  2. Inexpensive Raman Spectrometer for Undergraduate and Graduate Experiments and Research

    Science.gov (United States)

    Mohr, Christian; Spencer, Claire L.; Hippler, Michael

    2010-01-01

    We describe the construction and performance of an inexpensive modular Raman spectrometer that has been assembled in the framework of a fourth-year undergraduate project (costs below $5000). The spectrometer is based on a 4 mW 532 nm green laser pointer and a compact monochromator equipped with glass fiber optical connections, linear detector…

  3. Simple and inexpensive method for CT-guided stereotaxy

    Energy Technology Data Exchange (ETDEWEB)

    Wester, K; Sortland, O; Hauglie-Hanssen, E

    1981-01-01

    A simple and inexpensive method for CT-guided stereotaxy is described. The method requires neither sophisticated computer programs nor additional stereotactic equipment, such as special head holders for the CT, and can be easily obtained without technical assistance. The method is designed to yield the vertical coordinates.

  4. Classroom: inexpensive models for teaching atomic structure and ...

    African Journals Online (AJOL)

    Classroom: inexpensive models for teaching atomic structure and compounds at junior secondary school level of education. WHK Hordzi, BA Mensah. Abstract. No Abstract. Global Journal of Educational Research Vol. 2(1&2) 2003: 33-40. Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL ...

  5. Enthalpy of Vaporization and Vapor Pressures: An Inexpensive Apparatus

    Science.gov (United States)

    Battino, Rubin; Dolson, David A.; Hall, Michael A.; Letcher, Trevor M.

    2007-01-01

    A simple and inexpensive method to determine the enthalpy of vaporization of liquids by measuring vapor pressure as a function of temperature is described. The vapor pressures measured with the stopcock cell were higher than the literature values and those measured with the sidearm rubber septum cell were both higher and lower than literature…

  6. Build an Inexpensive Wind Tunnel to Test CO2 Cars

    Science.gov (United States)

    McCormick, Kevin

    2012-01-01

    As part of the technology education curriculum, the author's eighth-grade students design, build, test, and race CO2 vehicles. To help them in refining their designs, they use a wind tunnel to test for aerodynamic drag. In this article, the author describes how to build a wind tunnel using inexpensive, readily available materials. (Contains 1…

  7. Lightweight Inexpensive Ozone Lidar Telescope Using a Plastic Fresnel Lens

    Science.gov (United States)

    DeYoung, Russell J.; Notari, Anthony; Carrion, William; Pliutau, Denis

    2014-01-01

    An inexpensive lightweight ozone lidar telescope was designed, constructed and operated during an ozone lidar field campaign. This report summarizes the design parameters and performance of the plastic Fresnel lens telescope and shows the ozone lidar performance compared to Zemax calculations.

  8. Design, Development, and Characterization of an Inexpensive Portable Cyclic Voltammeter

    Science.gov (United States)

    Mott, Jenna R.; Munson, Paul J.; Kreuter, Rodney A.; Chohan, Balwant S.; Sykes, Danny G.

    2014-01-01

    The teaching of instrumental analysis for many small colleges and high schools continues to be stymied by high-cost, complicated maintenance, high power requirements, and often the sheer bulk of the instrumentation. Such issues have led us to develop inexpensive instruments as part of a SMILE initiative (small, mobile instruments for laboratory…

  9. Studies of avalanche photodiodes for scintillating fibre tracking readout

    International Nuclear Information System (INIS)

    Fenker, H.; Thomas, J.

    1993-01-01

    Avalanche Photodiodes (APDs) operating in ''Geiger Mode'' have been studied in a fibre tracking readout environment. A fast recharge circuit has been developed for high rate data taking, and results obtained from a model fibre tracker in the test beam at Brookhaven National Laboratory are presented. A high rate calibrated light source has been developed using a commercially available laser diode and has been used to measure the efficiency of the devices. The transmission of the light from a 1mm fibre onto a 0.5mm diameter APD surface has been identified as the main problem in the use of these particular devices for scintillating fibre tracking in the Superconducting Supercollider environment. Solutions to this problem are proposed

  10. Adaptive aperture for Geiger mode avalanche photodiode flash ladar systems

    Science.gov (United States)

    Wang, Liang; Han, Shaokun; Xia, Wenze; Lei, Jieyu

    2018-02-01

    Although the Geiger-mode avalanche photodiode (GM-APD) flash ladar system offers the advantages of high sensitivity and simple construction, its detection performance is influenced not only by the incoming signal-to-noise ratio but also by the absolute number of noise photons. In this paper, we deduce a hyperbolic approximation to estimate the noise-photon number from the false-firing percentage in a GM-APD flash ladar system under dark conditions. By using this hyperbolic approximation function, we introduce a method to adapt the aperture to reduce the number of incoming background-noise photons. Finally, the simulation results show that the adaptive-aperture method decreases the false probability in all cases, increases the detection probability provided that the signal exceeds the noise, and decreases the average ranging error per frame.

  11. Summary of conclusions of the vacuum photodiode working group

    International Nuclear Information System (INIS)

    Willis, W.

    1988-01-01

    This report presents the design of a 30 MV gun. In considering the design of the vacuum photodiode switched to drive the accelerating field in the gun, we have paid attention to the work of the groups on high-voltage pulsing and on the design of the laser. We have found that we can trade off reduced laser power at the cost of a higher charging voltage for our one stage accelerator. We have presented the various parameter sets to the two groups and attempted to measure their enthusiasm for each set, and we have chosen the set that seems to provide an equal level of difficulty on both sides. 1 fig., 1 tab

  12. Avalanche photodiode based time-of-flight mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Ogasawara, Keiichi, E-mail: kogasawara@swri.edu; Livi, Stefano A.; Desai, Mihir I.; Ebert, Robert W.; McComas, David J.; Walther, Brandon C. [Southwest Research Institute, 6220 Culebra Road, San Antonio, Texas 78238 (United States)

    2015-08-15

    This study reports on the performance of Avalanche Photodiodes (APDs) as a timing detector for ion Time-of-Flight (TOF) mass spectroscopy. We found that the fast signal carrier speed in a reach-through type APD enables an extremely short timescale response with a mass or energy independent <2 ns rise time for <200 keV ions (1−40 AMU) under proper bias voltage operations. When combined with a microchannel plate to detect start electron signals from an ultra-thin carbon foil, the APD comprises a novel TOF system that successfully operates with a <0.8 ns intrinsic timing resolution even using commercial off-the-shelf constant-fraction discriminators. By replacing conventional total-energy detectors in the TOF-Energy system, APDs offer significant power and mass savings or an anti-coincidence background rejection capability in future space instrumentation.

  13. An excess noise measurement system for weak responsivity avalanche photodiodes

    Science.gov (United States)

    Qiao, Liang; Dimler, Simon J.; Baharuddin, Aina N. A. P.; Green, James E.; David, John P. R.

    2018-06-01

    A system for measuring, with reduced photocurrent, the excess noise associated with the gain in avalanche photodiodes (APDs), using a transimpedance amplifier front-end and based on phase-sensitive detection is described. The system can reliably measure the excess noise power of devices, even when the un-multiplied photocurrent is low (~10 nA). This is more than one order of magnitude better than previously reported systems and represents a significantly better noise signal to noise ratio. This improvement in performance has been achieved by increasing the value of the feedback resistor and reducing the op-amp bandwidth. The ability to characterise APD performance with such low photocurrents enables the use of low power light sources such as light emitting diode rather than lasers to investigate the APD noise performance.

  14. Silicon-CsI detector array for heavy-ion reactions

    CERN Document Server

    Norbeck, E; Pogodin, P I; Cheng, Y W; Ingram, F D; Bjarki, O; Grévy, S; Magestro, D J; Molen, A M V; Westfall, G D

    2000-01-01

    An array of 60 silicon-CsI(Tl) detector telescopes has been developed along with associated electronics. The close packing of the telescopes required novel designs for the photodiodes and the silicon DELTA E detectors. Newly developed electronics include preamplifiers, shaping amplifiers, test pulse circuitry, and a module to monitor leakage currents in the silicon diodes. The array covers angles from 5 deg. to 18 deg. in the 4 pi Array at the National Superconducting Cyclotron Laboratory at Michigan State University. It measures protons to 150 MeV and has isotopic resolution for intermediate mass nuclei.

  15. Formation and properties of porous silicon layers

    International Nuclear Information System (INIS)

    Vitanov, P.; Kamenova, M.; Dimova-Malinovska, D.

    1993-01-01

    Preparation, properties and application of porous silicon films are investigated. Porous silicon structures were formed by an electrochemical etching process resulting in selective dissolution of the silicon substrate. The silicon wafers used with a resistivity of 5-10Ω.cm were doped with B to concentrations 6x10 18 -1x10 19 Ω.cm -3 in the temperature region 950 o C-1050 o C. The density of each porous films was determined from the weight loss during the anodization and it depends on the surface resistivity of the Si wafer. The density decreases with decreasing of the surface resistivity. The surface of the porous silicon layers was studied by X-ray photoelectron spectroscopy which indicates the presence of SiF 4 . The kinetic dependence of the anode potential and the porous layer thickness on the time of anodization in a galvanostatic regime for the electrolytes with various HF concentration were studied. In order to compare the properties of the resulting porous layers and to establish the dependence of the porosity on the electrolyte, three types of electrolytes were used: concentrated HF, diluted HF:H 2 O=1:1 and ethanol-hydrofluoric solutions HF:C 2 H 5 OH:H 2 O=2:1:1. High quality uniform and reproducible layers were formed using aqueous-ethanol-hydrofluoric electrolyte. Both Kikuchi's line and ring patterns were observed by TEM. The porous silicon layer was single crystal with the same orientation as the substrate. The surface shows a polycrystalline structure only. The porous silicon layers exhibit visible photoluminescence (PL) at room temperature under 480 nm Ar + laser line excitation. The peak of PL was observed at about 730 nm with FWHM about 90 nm. Photodiodes was made with a W-porous silicon junction. The current voltage and capacity voltage characteristics were similar to those of an isotype heterojunction diode. (orig.)

  16. The photodiode of UV-range on the basis of ZnSe

    Directory of Open Access Journals (Sweden)

    Perevertailo V. L.

    2010-03-01

    Full Text Available The construction and technology of Shottky photodiode on the basis of ZnSe, sensible in the ultraviolet region of spectrum are considered. Researches of electrophysical and photo-electric descriptions of photodiodes of Shottky Nі–ZnSe(Te,O–Іn are conducted and it is shown, that they can be applied in devices for radiometry and dissymmetry UV radiations in the ranges UVA, UVB and UVC. Comparison of parameters of developed UV photodiodes based on ZnSe with analogues showed that small capacitance and low value of dark current is their substantial difference of other ones.

  17. Streamlined, Inexpensive 3D Printing of the Brain and Skull

    OpenAIRE

    Naftulin, Jason S.; Kimchi, Eyal Y.; Cash, Sydney S.

    2015-01-01

    Neuroimaging technologies such as Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) collect three-dimensional data (3D) that is typically viewed on two-dimensional (2D) screens. Actual 3D models, however, allow interaction with real objects such as implantable electrode grids, potentially improving patient specific neurosurgical planning and personalized clinical education. Desktop 3D printers can now produce relatively inexpensive, good quality prints. We describe our process for...

  18. Evaluation of electrical crosstalk in high-density photodiode arrays for X-ray imaging applications

    International Nuclear Information System (INIS)

    Ji Fan; Juntunen, Mikko; Hietanen, Iiro

    2009-01-01

    Electrical crosstalk is one of the important parameters in the photodiode array detector for X-ray imaging applications, and it becomes more important when the density of the photodiode array becomes higher. This paper presents the design of the high-density photodiode array with 250 μm pitch and 50 μm gap. The electrical crosstalk of the demonstrated samples is evaluated and compared with different electrode configurations: cathode bias mode and anode bias mode. The measurement results show good electrical crosstalk, ∼0.23%, in cathode bias mode regardless of the bias voltage, and slightly decreased or increased electrical crosstalk in anode bias mode. Moreover, the quantum efficiency is also evaluated from the same samples, and it behaves similar to the electrical crosstalk. Finally, some design guidance of the high-density photodiode array is given based on the discussion.

  19. Readout of scintillator light with avalanche photodiodes for positron emission tomography

    International Nuclear Information System (INIS)

    Chen, Ruru; Fremout, A.; Tavernier, S.; Bruyndonckx, P.; Clement, D.; Loude, J.-F.; Morel, C.

    1999-01-01

    The noise properties and other relevant characteristics of avalanche photodiodes have been investigated with the perspective of replacing photomultiplier tubes in positron emission tomography. It is clearly demonstrated that they are a valid alternative to photomultiplier tubes in this application

  20. Tunneling Current Probe for Noncontract Wafer-Level Photodiode Array Testing

    National Research Council Canada - National Science Library

    Verdun, Horacio

    1999-01-01

    The Tunneling Current Probe (TCP) is an automated picometer-sensitive proximity sensor and current measurement system which measures the current through a photodiode detector array element by establishing a tunneling current...

  1. CsI(Tl)-photodiode detectors for gamma-ray spectroscopy

    CERN Document Server

    Fioretto, E; Viesti, G; Cinausero, M; Zuin, L; Fabris, D; Lunardon, M; Nebbia, G; Prete, G

    2000-01-01

    We report on the performances of CsI(Tl)-photodiode detectors for gamma-ray spectroscopy applications. Light output yield and energy resolution have been measured for different crystals and read-out configurations.

  2. Change of energy dependence for X-rays of photodiode detector

    International Nuclear Information System (INIS)

    Silva, M.F. da; Freitas, L.C. de

    1992-01-01

    The energy dependence of photodiode Siemens SFH-206 for X-rays beams of 24 kV to 50 kV was studied and compared with the ionization chamber of parallel plates. The photodiode presented 450% of maxim change response for the energy band studied. A study was made, using aluminium, acrylic, mylar aluminized and mylar graphitized filters and showed that the two last reduce this maxim change response to 101% and 108%, respectively. (C.G.C.)

  3. Novel technique for reliability testing of silicon integrated circuits

    NARCIS (Netherlands)

    Le Minh, P.; Wallinga, Hans; Woerlee, P.H.; van den Berg, Albert; Holleman, J.

    2001-01-01

    We propose a simple, inexpensive technique with high resolution to identify the weak spots in integrated circuits by means of a non-destructive photochemical process in which photoresist is used as the photon detection tool. The experiment was done to localize the breakdown link of thin silicon

  4. ASIC Readout Circuit Architecture for Large Geiger Photodiode Arrays

    Science.gov (United States)

    Vasile, Stefan; Lipson, Jerold

    2012-01-01

    The objective of this work was to develop a new class of readout integrated circuit (ROIC) arrays to be operated with Geiger avalanche photodiode (GPD) arrays, by integrating multiple functions at the pixel level (smart-pixel or active pixel technology) in 250-nm CMOS (complementary metal oxide semiconductor) processes. In order to pack a maximum of functions within a minimum pixel size, the ROIC array is a full, custom application-specific integrated circuit (ASIC) design using a mixed-signal CMOS process with compact primitive layout cells. The ROIC array was processed to allow assembly in bump-bonding technology with photon-counting infrared detector arrays into 3-D imaging cameras (LADAR). The ROIC architecture was designed to work with either common- anode Si GPD arrays or common-cathode InGaAs GPD arrays. The current ROIC pixel design is hardwired prior to processing one of the two GPD array configurations, and it has the provision to allow soft reconfiguration to either array (to be implemented into the next ROIC array generation). The ROIC pixel architecture implements the Geiger avalanche quenching, bias, reset, and time to digital conversion (TDC) functions in full-digital design, and uses time domain over-sampling (vernier) to allow high temporal resolution at low clock rates, increased data yield, and improved utilization of the laser beam.

  5. Characterization of midwave infrared InSb avalanche photodiode

    Energy Technology Data Exchange (ETDEWEB)

    Abautret, J., E-mail: johan.abautret@ies.univ-montp2.fr; Evirgen, A. [Université Montpellier, IES, UMR 5214, F-34095 Montpellier (France); CNRS, IES, UMR 5214, F-34095 Montpellier (France); SOFRADIR, BP 21, 38113 Veurey-Voroize (France); Perez, J. P.; Christol, P. [Université Montpellier, IES, UMR 5214, F-34095 Montpellier (France); CNRS, IES, UMR 5214, F-34095 Montpellier (France); Rothman, J. [CEA-LETI, 17 rue des Martyrs, 38054 Grenoble Cedex 9 (France); Cordat, A. [SOFRADIR, BP 21, 38113 Veurey-Voroize (France)

    2015-06-28

    This paper focuses on the InSb material potential for the elaboration of Avalanche Photodiodes (APD) for high performance infrared imaging applications, both in passive or active mode. The first InSb electron-APD structure was grown by molecular beam epitaxy, processed and electrically characterized. The device performances are at the state of the art for the InSb epi-diode technology, with a dark current density J(−50 mV) = 32 nA/cm{sup 2} at 77 K. Then, a pure electron injection was performed, and an avalanche gain, increasing exponentially, was observed with a gain value near 3 at −4 V at 77 K. The Okuto–Crowell model was used to determine the electron ionization coefficient α(E) in InSb, and the InSb gain behavior is compared with the one of InAs and MCT APDs.

  6. CMOS-based avalanche photodiodes for direct particle detection

    International Nuclear Information System (INIS)

    Stapels, Christopher J.; Squillante, Michael R.; Lawrence, William G.; Augustine, Frank L.; Christian, James F.

    2007-01-01

    Active Pixel Sensors (APSs) in complementary metal-oxide-semiconductor (CMOS) technology are augmenting Charge-Coupled Devices (CCDs) as imaging devices and cameras in some demanding optical imaging applications. Radiation Monitoring Devices are investigating the APS concept for nuclear detection applications and has successfully migrated avalanche photodiode (APD) pixel fabrication to a CMOS environment, creating pixel detectors that can be operated with internal gain as proportional detectors. Amplification of the signal within the diode allows identification of events previously hidden within the readout noise of the electronics. Such devices can be used to read out a scintillation crystal, as in SPECT or PET, and as direct-conversion particle detectors. The charge produced by an ionizing particle in the epitaxial layer is collected by an electric field within the diode in each pixel. The monolithic integration of the readout circuitry with the pixel sensors represents an improved design compared to the current hybrid-detector technology that requires wire or bump bonding. In this work, we investigate designs for CMOS APD detector elements and compare these to typical values for large area devices. We characterize the achievable detector gain and the gain uniformity over the active area. The excess noise in two different pixel structures is compared. The CMOS APD performance is demonstrated by measuring the energy spectra of X-rays from 55 Fe

  7. Laser annealing heals radiation damage in avalanche photodiodes

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Jin Gyu [University of Waterloo, Institute for Quantum Computing, Waterloo, ON (Canada); University of Waterloo, Department of Electrical and Computer Engineering, Waterloo, ON (Canada); Anisimova, Elena; Higgins, Brendon L.; Bourgoin, Jean-Philippe [University of Waterloo, Institute for Quantum Computing, Waterloo, ON (Canada); University of Waterloo, Department of Physics and Astronomy, Waterloo, ON (Canada); Jennewein, Thomas [University of Waterloo, Institute for Quantum Computing, Waterloo, ON (Canada); University of Waterloo, Department of Physics and Astronomy, Waterloo, ON (Canada); Canadian Institute for Advanced Research, Quantum Information Science Program, Toronto, ON (Canada); Makarov, Vadim [University of Waterloo, Institute for Quantum Computing, Waterloo, ON (Canada); University of Waterloo, Department of Electrical and Computer Engineering, Waterloo, ON (Canada); University of Waterloo, Department of Physics and Astronomy, Waterloo, ON (Canada)

    2017-12-15

    Avalanche photodiodes (APDs) are a practical option for space-based quantum communications requiring single-photon detection. However, radiation damage to APDs significantly increases their dark count rates and thus reduces their useful lifetimes in orbit. We show that high-power laser annealing of irradiated APDs of three different models (Excelitas C30902SH, Excelitas SLiK, and Laser Components SAP500S2) heals the radiation damage and several APDs are restored to typical pre-radiation dark count rates. Of nine samples we test, six APDs were thermally annealed in a previous experiment as another solution to mitigate the radiation damage. Laser annealing reduces the dark count rates further in all samples with the maximum dark count rate reduction factor varying between 5.3 and 758 when operating at -80 C. This indicates that laser annealing is a more effective method than thermal annealing. The illumination power to reach these reduction factors ranges from 0.8 to 1.6 W. Other photon detection characteristics, such as photon detection efficiency, timing jitter, and afterpulsing probability, fluctuate but the overall performance of quantum communications should be largely unaffected by these variations. These results herald a promising method to extend the lifetime of a quantum satellite equipped with APDs. (orig.)

  8. A case for Redundant Arrays of Inexpensive Disks (RAID)

    Science.gov (United States)

    Patterson, David A.; Gibson, Garth; Katz, Randy H.

    1988-01-01

    Increasing performance of CPUs and memories will be squandered if not matched by a similar performance increase in I/O. While the capacity of Single Large Expensive Disks (SLED) has grown rapidly, the performance improvement of SLED has been modest. Redundant Arrays of Inexpensive Disks (RAID), based on the magnetic disk technology developed for personal computers, offers an attractive alternative to SLED, promising improvements of an order of magnitude in performance, reliability, power consumption, and scalability. This paper introduces five levels of RAIDs, giving their relative cost/performance, and compares RAID to an IBM 3380 and a Fujitsu Super Eagle.

  9. A simple and inexpensive retainer for overdenture prosthesis

    Science.gov (United States)

    Kumar, Lakshya; Rao, Jitendra; Yadav, Akanksha

    2013-01-01

    This article describes a clinical case report of a 65-year-old male patient in which an overdenture was fabricated by using a simple, logical and inexpensive means of retentive device. The described mandibular overdenture involves a simple modification in the coping design and a wire lock mechanism which was fabricated during denture processing. The problems associated with copings were overcome by putting the patient on a regimen wherein topical fluoride was applied every week on the abutment. The denture, fabricated involving a wire lock mechanism, was highly retentive and stable. Patient was highly satisfied with the outcome of the treatment. PMID:23861281

  10. The compact and inexpensive arrowhead setup for holographic interferometry

    Energy Technology Data Exchange (ETDEWEB)

    Ladera, Celso L; Donoso, Guillermo, E-mail: clladera@usb.v [Departamento de Fisica, Universidad Simon BolIvar, Apdo. 89000, Caracas 1086 (Venezuela, Bolivarian Republic of)

    2011-07-15

    Hologram recording and holographic interferometry are intrinsically sensitive to phase changes, and therefore both are easily perturbed by minuscule optical path perturbations. It is therefore very convenient to bank on holographic setups with a reduced number of optical components. Here we present a compact off-axis holographic setup that requires neither a collimator nor a beam-splitter, and whose layout is reminiscent of an arrowhead. We show that this inexpensive setup is a good alternative for the study and applications of scientific holography by measuring small displacements and deformations of a body. The arrowhead setup will be found particularly useful for holography and holographic interferometry experiments and projects in teaching laboratories.

  11. Comparison of carrier transport mechanism under UV/Vis illumination in an AZO photodetector and an AZO/p-Si heterojunction photodiode produced by spray pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Shasti, M.; Mortezaali, A., E-mail: mortezaali@alzahra.ac.ir; Dariani, R. S. [Department of Physics, Alzahra University, Tehran 1993893973 (Iran, Islamic Republic of)

    2015-01-14

    In this study, Aluminum doped Zinc Oxide (AZO) layer is deposited on p-type silicon (p-Si) by spray pyrolysis method to fabricate ultraviolet-visible (UV/Vis) photodetector as Al doping process can have positive effect on the photodetector performance. Morphology, crystalline structure, and Al concentration of AZO layer are investigated by SEM, XRD, and EDX. The goal of this study is to analyze the mechanism of carrier transport by means of current-voltage characteristics under UV/Vis illumination in two cases: (a) electrodes connected to the surface of AZO layer and (b) electrodes connected to cross section of heterojunction (AZO/p-Si). Measurements indicate that the AZO/p-Si photodiode exhibits a higher photocurrent and lower photoresponse time under visible illumination with respect to AZO photodetector; while under UV illumination, the above result is inversed. Besides, the internal junction field of AZO/p-Si heterojunction plays an important role on this mechanism.

  12. Comparison of carrier transport mechanism under UV/Vis illumination in an AZO photodetector and an AZO/p-Si heterojunction photodiode produced by spray pyrolysis

    International Nuclear Information System (INIS)

    Shasti, M.; Mortezaali, A.; Dariani, R. S.

    2015-01-01

    In this study, Aluminum doped Zinc Oxide (AZO) layer is deposited on p-type silicon (p-Si) by spray pyrolysis method to fabricate ultraviolet-visible (UV/Vis) photodetector as Al doping process can have positive effect on the photodetector performance. Morphology, crystalline structure, and Al concentration of AZO layer are investigated by SEM, XRD, and EDX. The goal of this study is to analyze the mechanism of carrier transport by means of current-voltage characteristics under UV/Vis illumination in two cases: (a) electrodes connected to the surface of AZO layer and (b) electrodes connected to cross section of heterojunction (AZO/p-Si). Measurements indicate that the AZO/p-Si photodiode exhibits a higher photocurrent and lower photoresponse time under visible illumination with respect to AZO photodetector; while under UV illumination, the above result is inversed. Besides, the internal junction field of AZO/p-Si heterojunction plays an important role on this mechanism

  13. Modelization, fabrication and evaluation avalanche photodiodes polarized in Geiger mode for the single photon in astrophysics applications; Modelisation, fabrication et evaluation des photodiodes a avalanche polarisees en mode Geiger pour la detection du photon unique dans les applications Astrophysiques

    Energy Technology Data Exchange (ETDEWEB)

    Pellion, D

    2008-12-15

    The genesis of the work presented in this this is in the field of very high energy astrophysics. One century ago, scientists identified a new type of messenger coming from space: cosmic rays. This radiation consists of particles (photons or other) of very high energy which bombard the Earth permanently. The passage of cosmic radiations in the Earth's atmosphere results in the creation of briefs luminous flashes (5 ns) of very low intensity (1 pW), a Cherenkov flash, and then becomes visible on the ground. In the current state of the art the best detector of light today is the Photomultiplier tube (PMT), thanks to its characteristics of sensitivity and speed. But there are some drawbacks: low quantum efficiency, cost, weight etc. We present in this thesis a new alternative technology: silicon photon counters, made of photodiodes polarized in Geiger mode. This operating mode makes it possible to obtain an effect of multiplication comparable to that of the PMT. A physical and electrical model was developed to reproduce the behaviour of this detector. We then present in this thesis work an original technological process allowing the realization of these devices in the Center of Technology of LAAS-CNRS, with the simulation of each operation of the process. We developed a scheme for the electric characterization of the device, from the static mode to the dynamic mode, in order to check conformity with SILVACO simulations and to the initial model. Results are already excellent, given this is only a first prototype step, and comparable with the results published in the literature. These silicon devices can intervene in all the applications where there is a photomultiplier and replace it. The applications are thus very numerous and the growth of the market of these detectors is very fast. We present a first astrophysical experiment installed at the 'Pic du Midi' site which has detected Cherenkov flashes from cosmic rays with this new semiconductor technology

  14. Spatial redistribution of radiation in flip-chip photodiodes based on InAsSbP/InAs double heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Zakgeim, A. L. [Russian Academy of Sciences, Scientific and Technological Center for Microelectronics (Russian Federation); Il’inskaya, N. D.; Karandashev, S. A.; Lavrov, A. A., E-mail: ioffeled@mail.ru; Matveev, B. A.; Remennyy, M. A.; Stus’, N. M.; Usikova, A. A. [Russian Academy of Sciences, Ioffe Institute (Russian Federation); Cherniakov, A. E. [Russian Academy of Sciences, Scientific and Technological Center for Microelectronics (Russian Federation)

    2017-02-15

    The spatial distribution of equilibrium and nonequilibrium (including luminescent) IR (infrared) radiation in flip-chip photodiodes based on InAsSbP/InAs double heterostructures (λ{sub max} = 3.4 μm) is measured and analyzed; the structural features of the photodiodes, including the reflective properties of the ohmic contacts, are taken into account. Optical area enhancement due to multiple internal reflection in photodiodes with different geometric characteristics is estimated.

  15. Six-beam homodyne laser Doppler vibrometry based on silicon photonics technology.

    Science.gov (United States)

    Li, Yanlu; Zhu, Jinghao; Duperron, Matthieu; O'Brien, Peter; Schüler, Ralf; Aasmul, Soren; de Melis, Mirko; Kersemans, Mathias; Baets, Roel

    2018-02-05

    This paper describes an integrated six-beam homodyne laser Doppler vibrometry (LDV) system based on a silicon-on-insulator (SOI) full platform technology, with on-chip photo-diodes and phase modulators. Electronics and optics are also implemented around the integrated photonic circuit (PIC) to enable a simultaneous six-beam measurement. Measurement of a propagating guided elastic wave in an aluminum plate (speed ≈ 909 m/s @ 61.5 kHz) is demonstrated.

  16. Development of an integrated four-channel fast avalanche-photodiode detector system with nanosecond time resolution

    Science.gov (United States)

    Li, Zhenjie; Li, Qiuju; Chang, Jinfan; Ma, Yichao; Liu, Peng; Wang, Zheng; Hu, Michael Y.; Zhao, Jiyong; Alp, E. E.; Xu, Wei; Tao, Ye; Wu, Chaoqun; Zhou, Yangfan

    2017-10-01

    A four-channel nanosecond time-resolved avalanche-photodiode (APD) detector system is developed at Beijing Synchrotron Radiation. It uses a single module for signal processing and readout. This integrated system provides better reliability and flexibility for custom improvement. The detector system consists of three parts: (i) four APD sensors, (ii) four fast preamplifiers and (iii) a time-digital-converter (TDC) readout electronics. The C30703FH silicon APD chips fabricated by Excelitas are used as the sensors of the detectors. It has an effective light-sensitive area of 10 × 10 mm2 and an absorption layer thickness of 110 μm. A fast preamplifier with a gain of 59 dB and bandwidth of 2 GHz is designed to readout of the weak signal from the C30703FH APD. The TDC is realized by a Spartan-6 field-programmable-gate-array (FPGA) with multiphase method in a resolution of 1ns. The arrival time of all scattering events between two start triggers can be recorded by the TDC. The detector has been used for nuclear resonant scattering study at both Advanced Photon Source and also at Beijing Synchrotron Radiation Facility. For the X-ray energy of 14.4 keV, the time resolution, the full width of half maximum (FWHM) of the detector (APD sensor + fast amplifier) is 0.86 ns, and the whole detector system (APD sensors + fast amplifiers + TDC readout electronics) achieves a time resolution of 1.4 ns.

  17. Modelization, fabrication and evaluation avalanche photodiodes polarized in Geiger mode for the single photon in astrophysics applications

    International Nuclear Information System (INIS)

    Pellion, D.

    2008-12-01

    The genesis of the work presented in this this is in the field of very high energy astrophysics. One century ago, scientists identified a new type of messenger coming from space: cosmic rays. This radiation consists of particles (photons or other) of very high energy which bombard the Earth permanently. The passage of cosmic radiations in the Earth's atmosphere results in the creation of briefs luminous flashes (5 ns) of very low intensity (1 pW), a Cherenkov flash, and then becomes visible on the ground. In the current state of the art the best detector of light today is the Photomultiplier tube (PMT), thanks to its characteristics of sensitivity and speed. But there are some drawbacks: low quantum efficiency, cost, weight etc. We present in this thesis a new alternative technology: silicon photon counters, made of photodiodes polarized in Geiger mode. This operating mode makes it possible to obtain an effect of multiplication comparable to that of the PMT. A physical and electrical model was developed to reproduce the behaviour of this detector. We then present in this thesis work an original technological process allowing the realization of these devices in the Center of Technology of LAAS-CNRS, with the simulation of each operation of the process. We developed a scheme for the electric characterization of the device, from the static mode to the dynamic mode, in order to check conformity with SILVACO simulations and to the initial model. Results are already excellent, given this is only a first prototype step, and comparable with the results published in the literature. These silicon devices can intervene in all the applications where there is a photomultiplier and replace it. The applications are thus very numerous and the growth of the market of these detectors is very fast. We present a first astrophysical experiment installed at the 'Pic du Midi' site which has detected Cherenkov flashes from cosmic rays with this new semiconductor technology. (author)

  18. Blenderized feeding formulas with nutritious and inexpensive foods

    Directory of Open Access Journals (Sweden)

    Ana Paula Lança BENTO

    Full Text Available ABSTRACT Objective: To propose an inexpensive blenderized tube feeding formula consisting of foods with standard nutritional composition that meets the nutritional requirements of individuals aged more than 51 years. Methods: The enteral diets were formulated mainly with fresh foods and tested for their physical (homogeneity, stability, osmolality, pH, and flow rate and chemical (moisture, ash, protein, lipids, energy, crude fiber, vitamin C, calcium, iron, magnesium, and zinc characteristics. The cost was determined by surveying item prices in supermarkets and stores that specialize in nutritional support. Results: The blenderized tube feeding formula was stable and homogeneous, and had slightly acidic pH, hypertonic osmolality (603mOsm/kg, and flow rate comparable with gravity drip (21 minutes. Proximate composition analysis indicated appropriate levels of proteins, lipids, vitamin C, and zinc. The mean cost of 2000kcal of the standard blenderized tube feeding formula was R$ 12.3±1.4, which is 70% cheaper than the mean cost of similar commercial enteral formulas. Conclusion: The planned diet can be an excellent choice for patients using blenderized tube feeding formulas as it consisted of habitual food items, had physical and nutritional quality, and was inexpensive.

  19. An inexpensive high-temperature optical fiber thermometer

    International Nuclear Information System (INIS)

    Moore, Travis J.; Jones, Matthew R.; Tree, Dale R.; Allred, David D.

    2017-01-01

    An optical fiber thermometer consists of an optical fiber whose tip is coated with a highly conductive, opaque material. When heated, this sensing tip becomes an isothermal cavity that emits like a blackbody. This emission is used to predict the sensing tip temperature. In this work, analytical and experimental research has been conducted to further advance the development of optical fiber thermometry. An inexpensive optical fiber thermometer is developed by applying a thin coating of a high-temperature cement onto the tip of a silica optical fiber. An FTIR spectrometer is used to detect the spectral radiance exiting the fiber. A rigorous mathematical model of the irradiation incident on the detection system is developed. The optical fiber thermometer is calibrated using a blackbody radiator and inverse methods are used to predict the sensing tip temperature when exposed to various heat sources. - Highlights: • An inexpensive coating for an optical fiber thermometer sensing tip is tested. • Inverse heat transfer methods are used to estimate the sensing tip temperature. • An FTIR spectrometer is used as the detector to test the optical fiber thermometer using various heat sources.

  20. An inexpensive yet realistic model for teaching vasectomy

    Directory of Open Access Journals (Sweden)

    Taylor M. Coe

    2015-04-01

    Full Text Available Purpose Teaching the no-scalpel vasectomy is important, since vasectomy is a safe, simple, and cost-effective method of contraception. This minimally invasive vasectomy technique involves delivering the vas through the skin with specialized tools. This technique is associated with fewer complications than the traditional incisional vasectomy (1. One of the most challenging steps is the delivery of the vas through a small puncture in the scrotal skin, and there is a need for a realistic and inexpensive scrotal model for beginning learners to practice this step. Materials and Methods After careful observation using several scrotal models while teaching residents and senior trainees, we developed a simplified scrotal model that uses only three components–bicycle inner tube, latex tubing, and a Penrose drain. Results This model is remarkably realistic and allows learners to practice a challenging step in the no-scalpel vasectomy. The low cost and simple construction of the model allows wide dissemination of training in this important technique. Conclusions We propose a simple, inexpensive model that will enable learners to master the hand movements involved in delivering the vas through the skin while mitigating the risks of learning on patients.

  1. A high-sensitivity, fast-response, rapid-recovery p–n heterojunction photodiode based on rutile TiO{sub 2} nanorod array on p-Si(1 1 1)

    Energy Technology Data Exchange (ETDEWEB)

    Selman, Abbas M., E-mail: alabbasiabbas@yahoo.co.uk [Nano-Optoelectronics Research and Technology Laboratory (N.O.R.), School of Physics, Universiti Sains Malaysia, Penang 11800 (Malaysia); Department of Pharmacology and Toxicology, College of Pharmacy, University of Kufa, Najaf (Iraq); Hassan, Z.; Husham, M.; Ahmed, Naser M. [Nano-Optoelectronics Research and Technology Laboratory (N.O.R.), School of Physics, Universiti Sains Malaysia, Penang 11800 (Malaysia)

    2014-06-01

    The growth and characterization of a p–n heterojunction photodiode were studied. This photodiode was based on rutile TiO{sub 2} nanorods (NRs) grown on p-type (1 1 1)-oriented silicon substrate seeded with a TiO{sub 2} layer synthesized by radio-frequency (RF) reactive magnetron sputtering. Chemical bath deposition (CBD) was performed to grow rutile TiO{sub 2} NRs on Si substrate. The structural and optical properties of the sample were studied by X-ray diffraction (XRD) and field emission-scanning electron microscopy (FESEM) analyses. Results showed the tetragonal rutile structure of the synthesized TiO{sub 2} NRs. Optical properties were further examined by photoluminescence spectroscopy, and a high-intensity UV peak centered at around 392 nm compared with visible defect peaks centered at 527 and 707 nm was observed. Upon exposure to 395 nm light (2.3 mW/cm) at five-bias voltage, the device showed 2.9 × 10{sup 2} sensitivity. In addition, the internal gain of the photodiode was 3.92, and the photoresponse peak was 106 mA/W. Furthermore, the photocurrent was 3.06 × 10{sup −4} A. The response and the recovery times were calculated to be 10.4 and 11 ms, respectively, upon illumination to a pulse UV light (405 nm, 0.22 mW/cm{sup 2}) at five-bias voltage. All of these results demonstrate that this high-quality photodiode can be a promising candidate as a low-cost UV photodetector for commercially integrated photoelectronic applications.

  2. On the use of single large-area photodiodes in scintillation counters

    International Nuclear Information System (INIS)

    Morrell, C.

    1989-12-01

    The compilation of this review was originally intended to assess the possibility of using photodiode-based scintillation counters in fluorescence EXAFS (or FLEXAFS) systems as a low-cost alternative to photomultiplier-based counters. The X-ray energies encountered in FLEXAFS experiments range from a few keV to a few tens of keV, and detectors are required to have some energy resolution and/or high count-rate capability in order to optimize the quality of data collected. The results presented in the reviewed literature imply strongly that photodiodes do not compete successfully with photomultipliers in scintillation counting systems for X-ray energies below the order of 100keV, at least at the present stage of photodiode technology. Nevertheless it is likely that there are other applications requiring X-ray detectors for which a photodiode-based scintillation counter may be perfectly adequate, and it is therefore felt that such a review is still useful. In addition, large-area single photodiodes have much to offer as X-ray detectors in their own right, and several of the considerations regarding their use in scintillation counters are highly relevant to this application. (author)

  3. Evaluation of phase sensitive detection method and Si avalanche photodiode for radiation thermometry

    International Nuclear Information System (INIS)

    Hobbs, M J; Tan, C H; Willmott, J R

    2013-01-01

    We report the evaluation of Si avalanche photodiodes (APDs) for use in radiation thermometry as an alternative to Si photodiodes. We compared their performance when operated under phase sensitive detection (PSD), where the signal is modulated, and direct detection (DD) methods. A Si APD was compared with a Si photodiode with reference black body temperatures of 275 to 600°C, in terms of the mean output voltage and signal-to-noise ratio (SNR), measured at different APD gain values. We found that using both PSD and DD methods, the high internal gain of the Si APD achieved a lower minimum detection temperature in order to satisfy a specific minimum output voltage of the detector-preamplifier combination employed. The use of PSD over DD for the Si APD allowed for improved performance of the thermometer, with a lower minimum measurable temperature, as well as improvement in the SNR. For instance we found that at 350°C, the Si APD biased at 150 V using PSD can provide ∼ 88 times enhancement in the system SNR over that of a Si photodiode using DD. A corresponding temperature error of ±0.05°C was achieved using the APD with PSD compared to an error of ±2.75°C measured using the Si photodiode with DD.

  4. A room temperature LSO/PIN photodiode PET detector module that measures depth of interaction

    International Nuclear Information System (INIS)

    Moses, W.W.; Derenzo, S.E.; Melcher, C.L.; Manente, R.A.

    1994-11-01

    We present measurements of a 4 element PET detector module that uses a 2x2 array of 3 mm square PIN photodiodes to both measure the depth of interaction (DOI) and identify the crystal of interaction. Each photodiode is coupled to one end of a 3x3x25 mm LSO crystal, with the opposite ends of all 4 crystals attached to a single PMT that provides a timing signal and initial energy discrimination. Each LSO crystal is coated with a open-quotes lossyclose quotes reflector, so the ratio of light detected in the photodiode and PMT depends on the position of interaction in the crystal, and is used to determine this position on an event by event basis. This module is operated at +25 degrees C with a photodiode amplifier peaking time of 2 μs. When excited by a collimated beam of 511 keV photons at the photodiode end of the module (i.e. closest to the patient), the DOI resolution is 4 mm fwhm and the crystal of interaction is identified correctly 95% of the time. When excited at the opposite end of the module, the DOI resolution is 13 mm fwhm and the crystal of interaction is identified correctly 73% of the time. The channel to channel variations in performance are minimal

  5. Low-resistivity photon-transparent window attached to photo-sensitive silicon detector

    International Nuclear Information System (INIS)

    Holland, S.E.

    2000-01-01

    The invention comprises a combination of a low resistivity, or electrically conducting, silicon layer that is transparent to long or short wavelength photons and is attached to the backside of a photon-sensitive layer of silicon, such as a silicon wafer or chip. The window is applied to photon sensitive silicon devices such as photodiodes, charge-coupled devices, active pixel sensors, low-energy x-ray sensors and other radiation detectors. The silicon window is applied to the back side of a photosensitive silicon wafer or chip so that photons can illuminate the device from the backside without interference from the circuit printed on the frontside. A voltage sufficient to fully deplete the high-resistivity photosensitive silicon volume of charge carriers is applied between the low-resistivity back window and the front, patterned, side of the device. This allows photon-induced charge created at the backside to reach the front side of the device and to be processed by any circuitry attached to the front side. Using the inventive combination, the photon sensitive silicon layer does not need to be thinned beyond standard fabrication methods in order to achieve full charge-depletion in the silicon volume. In one embodiment, the inventive backside window is applied to high resistivity silicon to allow backside illumination while maintaining charge isolation in CCD pixels

  6. Silicon Qubits

    Energy Technology Data Exchange (ETDEWEB)

    Ladd, Thaddeus D. [HRL Laboratories, LLC, Malibu, CA (United States); Carroll, Malcolm S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2018-02-28

    Silicon is a promising material candidate for qubits due to the combination of worldwide infrastructure in silicon microelectronics fabrication and the capability to drastically reduce decohering noise channels via chemical purification and isotopic enhancement. However, a variety of challenges in fabrication, control, and measurement leaves unclear the best strategy for fully realizing this material’s future potential. In this article, we survey three basic qubit types: those based on substitutional donors, on metal-oxide-semiconductor (MOS) structures, and on Si/SiGe heterostructures. We also discuss the multiple schema used to define and control Si qubits, which may exploit the manipulation and detection of a single electron charge, the state of a single electron spin, or the collective states of multiple spins. Far from being comprehensive, this article provides a brief orientation to the rapidly evolving field of silicon qubit technology and is intended as an approachable entry point for a researcher new to this field.

  7. Silicon photo-multiplier radiation hardness tests with a beam controlled neutron source

    International Nuclear Information System (INIS)

    Angelone, M.; Pillon, M.; Faccini, R.; Pinci, D.; Baldini, W.; Calabrese, R.; Cibinetto, G.; Cotta Ramusino, A.; Malaguti, R.; Pozzati, M.

    2010-01-01

    Radiation hardness tests were performed at the Frascati Neutron Generator on silicon Photo-Multipliers that were made of semiconductor photon detectors built from a square matrix of avalanche photo-diodes on a silicon substrate. Several samples from different manufacturers have been irradiated, integrating up to 7x10 10 1-MeV-equivalent neutrons per cm 2 . Detector performance was recorded during the neutron irradiation, and a gradual deterioration of their properties began after an integrated fluence of the order of 10 8 1-MeV-equivalent neutrons per cm 2 was reached.

  8. Miniature probe with semiconductor photodiode for measuring dose rates in radiotherapy

    International Nuclear Information System (INIS)

    Burian, A.

    1991-01-01

    The probe is designed for gaining information on the magnitude and spatial distribution of the dose which will be absorbed by the patient's body during radiotherapy. The probe satisfies requirements of high-level miniaturization and requirements on the shape and tissue-equivalence of the casing, as well as on efficient electromagnetic shielding. It is fitted with a miniature photodiode. Conductive carbon cement was used for attaching contacts to the photodiode. Efficient electromagnetic shielding was achieved by means of a carbon-based conductive layer. The photodiode casing was made from a mixture of organic materials whose biogenic elements approximate the standard soft human tissue. The geometry of the casing is adapted to the particular field of application of the probe. (Z.S). 2 figs

  9. Indium phosphide-based monolithically integrated PIN waveguide photodiode readout for resonant cantilever sensors

    Energy Technology Data Exchange (ETDEWEB)

    Siwak, N. P. [Department of Electrical and Computer Engineering, Institute for Systems Research, University of Maryland, College Park, Maryland 20742 (United States); Laboratory for the Physical Sciences, 8050 Greenmead Drive, College Park, Maryland 20740 (United States); Fan, X. Z.; Ghodssi, R. [Department of Electrical and Computer Engineering, Institute for Systems Research, University of Maryland, College Park, Maryland 20742 (United States); Kanakaraju, S.; Richardson, C. J. K. [Laboratory for the Physical Sciences, 8050 Greenmead Drive, College Park, Maryland 20740 (United States)

    2014-10-06

    An integrated photodiode displacement readout scheme for a microelectromechanical cantilever waveguide resonator sensing platform is presented. III-V semiconductors are used to enable the monolithic integration of passive waveguides with active optical components. This work builds upon previously demonstrated results by measuring the displacement of cantilever waveguide resonators with on-chip waveguide PIN photodiodes. The on-chip integration of the readout provides an additional 70% improvement in mass sensitivity compared to off-chip photodetector designs due to measurement stability and minimized coupling loss. In addition to increased measurement stability, reduced packaging complexity is achieved due to the simplicity of the readout design. We have fabricated cantilever waveguides with integrated photodetectors and experimentally characterized these cantilever sensors with monolithically integrated PIN photodiodes.

  10. Low-Noise Large-Area Photoreceivers with Low Capacitance Photodiodes

    Science.gov (United States)

    Joshi, Abhay M. (Inventor); Datta, Shubhashish (Inventor)

    2013-01-01

    A quad photoreceiver includes a low capacitance quad InGaAs p-i-n photodiode structure formed on an InP (100) substrate. The photodiode includes a substrate providing a buffer layer having a metal contact on its bottom portion serving as a common cathode for receiving a bias voltage, and successive layers deposited on its top portion, the first layer being drift layer, the second being an absorption layer, the third being a cap layer divided into four quarter pie shaped sections spaced apart, with metal contacts being deposited on outermost top portions of each section to provide output terminals, the top portions being active regions for detecting light. Four transimpedance amplifiers have input terminals electrically connected to individual output terminals of each p-i-n photodiode.

  11. Some n-p (Hg,Cd)Te photodiodes for 8-14 micrometer heterodyne applications

    Science.gov (United States)

    Shanley, J. F.; Flanagan, C. T.

    1980-01-01

    The results describing the dc and CO2 laser heterodyne characteristics of a three element photodiode array and single element and four element photodiode arrays are presented. The measured data shows that the n(+)-p configuration is capable of achieving bandwidths of 475 to 725 MHz and noise equivalent powers of 3.2 x 10 to the minus 20th power W/Hz at 77 K and 1.0 x 10 to the minus 19th power W/Hz at 145 K. The n(+)-n(-)-p photodiodes exhibited wide bandwidths (approximately 2.0 GHz) and fairly good effective heterodyne quantum efficiencies (approximately 13-30 percent at 2.0 GHz). Noise equivalent powers ranging from 1.44 x 10 to the minus 19th power W/Hz to 6.23 x 10 to the minus 20th power W/Hz were measured at 2.0 GHz.

  12. An inexpensive instrument for measuring wave exposure and water velocity

    Science.gov (United States)

    Figurski, J.D.; Malone, D.; Lacy, J.R.; Denny, M.

    2011-01-01

    Ocean waves drive a wide variety of nearshore physical processes, structuring entire ecosystems through their direct and indirect effects on the settlement, behavior, and survivorship of marine organisms. However, wave exposure remains difficult and expensive to measure. Here, we report on an inexpensive and easily constructed instrument for measuring wave-induced water velocities. The underwater relative swell kinetics instrument (URSKI) is a subsurface float tethered by a short (<1 m) line to the seafloor. Contained within the float is an accelerometer that records the tilt of the float in response to passing waves. During two field trials totaling 358 h, we confirmed the accuracy and precision of URSKI measurements through comparison to velocities measured by an in situ acoustic Doppler velocimeter and those predicted by a standard swell model, and we evaluated how the dimensions of the devices, its buoyancy, and sampling frequency can be modified for use in a variety of environments.

  13. A novel inexpensive murine model of oral chronic digitalization.

    Science.gov (United States)

    Helber, Izo; Kanashiro, Rosemeire M; Alarcon, Ernesto A; Antonio, Ednei L; Tucci, Paulo J F

    2004-01-01

    A novel inexpensive murine model of oral administration of digitoxin (100 micro g/kg per day) added to routine chow is described. Serum digitoxin levels achieved after oral (n = 5; 116 +/- 14 ng/mL) and subcutaneous (n = 5; 124 +/- 11 ng/mL) administration were similar. A significant increase in the maximal left ventricular pressure rise of treated (n = 9) compared with control (n = 6) rats (dP/dt: 8956 +/- 233 vs 7980 +/- 234 mmHg/s, respectively; P = 0.01) characterized the positive inotropic action of digitoxin. In addition, no differences were observed in treated compared with control rats with regard to the electrocardiogram and systolic and diastolic left ventricular pressures.

  14. Parallel random number generator for inexpensive configurable hardware cells

    Science.gov (United States)

    Ackermann, J.; Tangen, U.; Bödekker, B.; Breyer, J.; Stoll, E.; McCaskill, J. S.

    2001-11-01

    A new random number generator ( RNG) adapted to parallel processors has been created. This RNG can be implemented with inexpensive hardware cells. The correlation between neighboring cells is suppressed with smart connections. With such connection structures, sequences of pseudo-random numbers are produced. Numerical tests including a self-avoiding random walk test and the simulation of the order parameter and energy of the 2D Ising model give no evidence for correlation in the pseudo-random sequences. Because the new random number generator has suppressed the correlation between neighboring cells which is usually observed in cellular automaton implementations, it is applicable for extended time simulations. It gives an immense speed-up factor if implemented directly in configurable hardware, and has recently been used for long time simulations of spatially resolved molecular evolution.

  15. The CCRT: An inexpensive cosmic ray muon detector

    International Nuclear Information System (INIS)

    Harpell, E.; Langeveld, W.; McShurley, D.; Shapiro, S.; Venuti, J.

    1995-01-01

    In this article the authors describe an inexpensive cosmic ray counter useful for physics demonstrations and experiments. Although many university departments use cosmic ray detectors as part of their upper division laboratory courses, these are often large and expensive devices requiring specialized equipment not usually accessible in high school and college programs. This detector is very compact and can be constructed for about $350 using commercially available materials and small scintillator panels that may be available (in limited supply) from Stanford Linear Accelerator Center (SLAC) and perhaps other accelerator laboratories. In the following, the authors provide detailed instructions for the construction of the detector as well as suggestions for its use in the classroom and laboratory

  16. Sound cable crossing brings inexpensive electric power to Long Island

    International Nuclear Information System (INIS)

    Grzan, J.; Goyette, R.

    1992-01-01

    This paper reports that while many electric-utility customers in New York State benefit from inexpensive hydroelectric power from Canada and upstate New York, lack of sufficient transmission connections have prevented this electricity from reaching Long Island. However, a newly constructed underground/underwater link capable of carrying 700-MW now transmits low-cost electricity to the island, saving money for customers. The self-contained fluid-filled cable used for the underwater portion of the project is the largest underwater cable in the world. The use of high-pressure, fluid-filled pipe-type cable on the land portion represents the largest application of paper-polypropylene-paper (PPP) insulated cable in the United States. State-of-the-art technologies were implemented in the use of temperature monitoring and leak detection systems, SF 6 gas-insulated substation, and underwater cable laying and embedment techniques

  17. A new inexpensive electrochemical meter for oxygen in sodium coolant

    International Nuclear Information System (INIS)

    Periaswami, G.; Rajan Babu, S.S.; Mathews, C.K.

    1987-01-01

    This report describes the development of an inexpensive oxygen meter for sodium coolant and gives the results of the test experiments. Calcia stabilized zirconia has been found to have necessary domain boundary characteristics at low temperatures for use as oxygen sensor in liquid sodium system. It is possible to obtain acceptable sensor cell resistance at temperatures as low as 230 C if K, K 2 O or Na, Na 2 O is used as reference electrode. The performance of these cells has been tested in bench top sodium loops over long periods. Their performance in terms of cell-out put variation with change in oxygen concentration in sodium has been found to be satisfactory. They also have sufficiently long life times since the kinetics of sodium attack on the electrolyte is slow at low temperatures. (author). 17 refs., 6 figs

  18. Silicon Pixel Detectors for Synchrotron Applications

    CERN Document Server

    Stewart, Graeme Douglas

    Recent advances in particle accelerators have increased the demands being placed on detectors. Novel detector designs are being implemented in many different areas including, for example, high luminosity experiments at the LHC or at next generation synchrotrons. The purpose of this thesis was to characterise some of these novel detectors. The first of the new detector types is called a 3D detector. This design was first proposed by Parker, Kenney and Segal (1997). In this design, doped electrodes are created that extend through the silicon substrate. When compared to a traditional photodiode with electrodes on the opposing surfaces, the 3D design can combine a reasonable detector thickness with a small electrode spacing resulting in fast charge collection and limited charge sharing. The small electrode spacing leads to the detectors having lower depletion voltages. This, combined with the fast collection time, makes 3D detectors a candidate for radiation hard applications. These applications include the upgra...

  19. Gamma Large Area Silicon Telescope (GLAST)

    International Nuclear Information System (INIS)

    Godfrey, G.L.

    1993-11-01

    The recent discoveries and excitement generated by EGRET have prompted an investigation into modern technologies ultimately leading to the next generation space-based gamma ray telescope. The goal is to design a detector that will increase the data acquisition rate by almost two orders of magnitude beyond EGRET, while at the same time improving on the angular resolution, the energy measurement of reconstructed gamma rays, and the triggering capability of the instrument. The GLAST proposal is based on the assertion that silicon particle detectors are the technology of choice for space application: no consumables, no gas volume, robust (versus fragile), long lived, and self triggering. The GLAST detector is roughly modeled after EGRET in that a tracking module precedes a calorimeter. The GLAST Tracker has planes of thin radiatior interspersed with planes of crossed-strip (x,y) 300-μm-pitch silicon detectors to measure the coordinates of converted electron-positron pairs. The gap between the layers (∼5 cm) provides a lever arm in track fitting resulting in an angular resolution of 0.1 degree at high energy (the low energy angular resolution at 100 MeV would be about 2 degree, limited by multiple scattering). A possible GLAST calorimeter is made of a mosaic of Csl crystals of order 10 r.l. in depth, with silicon photodiodes readout. The increased depth of the GLAST calorimeter over EGRET's extends the energy range to about 300 GeV

  20. Digital system for acquiring signals from photodiode arrays. No. Program Element 2317-08-03

    International Nuclear Information System (INIS)

    Le Guen, M.; Meric, B.

    1981-01-01

    A model of circuit allowing the digitization and the memorization of signals coming from linear arrays of photodiodes have been realized. The authors first recall the organization and present in the second part some test results on experimental sites. The model consists of 1 - an acquisition, memorization and visualization card (AMV card) for the data from RETICON 121 photodiode strips, 2 - a series transfer card for the memorized data, and 3 - an interface and multiplexing card associated with a system using a 6800 microprocessor allowing the management of eight acquisition cards [fr

  1. Application of PIN photodiodes on the detection of X-rays generated in an electron accelerator

    International Nuclear Information System (INIS)

    Mondragon-Contreras, L.; Ramirez-Jimenez, F.J.; Garcia-Hernandez, J.M.; Torres-Bribiesca, M.A.; Lopez-Callejas, R.; Aguilera-Reyes, E.F.; Pena-Eguiluz, R.; Lopez-Valdivia, H.; Carrasco-Abrego, H.

    2009-01-01

    PIN photodiodes are used in a novel application for the determination, within the energy range from 90 to 485 keV, of the intensity of X-rays generated by an experimental electron accelerator. An easily assembled X-ray monitor has been built with a low-cost PIN photodiode and operational amplifiers. The output voltage signal obtained from this device can be related to the electron beam current and the accelerating voltage of the accelerator in order to estimate the dose rate delivered by bremsstrahlung.

  2. Simulation of Silicon Photomultiplier Signals

    Science.gov (United States)

    Seifert, Stefan; van Dam, Herman T.; Huizenga, Jan; Vinke, Ruud; Dendooven, Peter; Lohner, Herbert; Schaart, Dennis R.

    2009-12-01

    In a silicon photomultiplier (SiPM), also referred to as multi-pixel photon counter (MPPC), many Geiger-mode avalanche photodiodes (GM-APDs) are connected in parallel so as to combine the photon counting capabilities of each of these so-called microcells into a proportional light sensor. The discharge of a single microcell is relatively well understood and electronic models exist to simulate this process. In this paper we introduce an extended model that is able to simulate the simultaneous discharge of multiple cells. This model is used to predict the SiPM signal in response to fast light pulses as a function of the number of fired cells, taking into account the influence of the input impedance of the SiPM preamplifier. The model predicts that the electronic signal is not proportional to the number of fired cells if the preamplifier input impedance is not zero. This effect becomes more important for SiPMs with lower parasitic capacitance (which otherwise is a favorable property). The model is validated by comparing its predictions to experimental data obtained with two different SiPMs (Hamamatsu S10362-11-25u and Hamamatsu S10362-33-25c) illuminated with ps laser pulses. The experimental results are in good agreement with the model predictions.

  3. Near-infrared sub-bandgap all-silicon photodetectors: state of the art and perspectives.

    Science.gov (United States)

    Casalino, Maurizio; Coppola, Giuseppe; Iodice, Mario; Rendina, Ivo; Sirleto, Luigi

    2010-01-01

    Due to recent breakthroughs, silicon photonics is now the most active discipline within the field of integrated optics and, at the same time, a present reality with commercial products available on the market. Silicon photodiodes are excellent detectors at visible wavelengths, but the development of high-performance photodetectors on silicon CMOS platforms at wavelengths of interest for telecommunications has remained an imperative but unaccomplished task so far. In recent years, however, a number of near-infrared all-silicon photodetectors have been proposed and demonstrated for optical interconnect and power-monitoring applications. In this paper, a review of the state of the art is presented. Devices based on mid-bandgap absorption, surface-state absorption, internal photoemission absorption and two-photon absorption are reported, their working principles elucidated and their performance discussed and compared.

  4. Near-Infrared Sub-Bandgap All-Silicon Photodetectors: State of the Art and Perspectives

    Directory of Open Access Journals (Sweden)

    Luigi Sirleto

    2010-11-01

    Full Text Available Due to recent breakthroughs, silicon photonics is now the most active discipline within the field of integrated optics and, at the same time, a present reality with commercial products available on the market. Silicon photodiodes are excellent detectors at visible wavelengths, but the development of high-performance photodetectors on silicon CMOS platforms at wavelengths of interest for telecommunications has remained an imperative but unaccomplished task so far. In recent years, however, a number of near-infrared all-silicon photodetectors have been proposed and demonstrated for optical interconnect and power-monitoring applications. In this paper, a review of the state of the art is presented. Devices based on mid-bandgap absorption, surface-state absorption, internal photoemission absorption and two-photon absorption are reported, their working principles elucidated and their performance discussed and compared.

  5. Design and construction of an inexpensive homemade plant growth chamber.

    Science.gov (United States)

    Katagiri, Fumiaki; Canelon-Suarez, Dario; Griffin, Kelsey; Petersen, John; Meyer, Rachel K; Siegle, Megan; Mase, Keisuke

    2015-01-01

    Plant growth chambers produce controlled environments, which are crucial in making reproducible observations in experimental plant biology research. Commercial plant growth chambers can provide precise controls of environmental parameters, such as temperature, humidity, and light cycle, and the capability via complex programming to regulate these environmental parameters. But they are expensive. The high cost of maintaining a controlled growth environment is often a limiting factor when determining experiment size and feasibility. To overcome the limitation of commercial growth chambers, we designed and constructed an inexpensive plant growth chamber with consumer products for a material cost of $2,300. For a comparable growth space, a commercial plant growth chamber could cost $40,000 or more. Our plant growth chamber had outside dimensions of 1.5 m (W) x 1.8 m (D) x 2 m (H), providing a total growth area of 4.5 m2 with 40-cm high clearance. The dimensions of the growth area and height can be flexibly changed. Fluorescent lights with large reflectors provided a relatively spatially uniform photosynthetically active radiation intensity of 140-250 μmoles/m2/sec. A portable air conditioner provided an ample cooling capacity, and a cooling water mister acted as a powerful humidifier. Temperature, relative humidity, and light cycle inside the chamber were controlled via a z-wave home automation system, which allowed the environmental parameters to be monitored and programmed through the internet. In our setting, the temperature was tightly controlled: 22.2°C±0.8°C. The one-hour average relative humidity was maintained at 75%±7% with short spikes up to ±15%. Using the interaction between Arabidopsis and one of its bacterial pathogens as a test experimental system, we demonstrate that experimental results produced in our chamber were highly comparable to those obtained in a commercial growth chamber. In summary, our design of an inexpensive plant growth chamber

  6. Design and construction of an inexpensive homemade plant growth chamber.

    Directory of Open Access Journals (Sweden)

    Fumiaki Katagiri

    Full Text Available Plant growth chambers produce controlled environments, which are crucial in making reproducible observations in experimental plant biology research. Commercial plant growth chambers can provide precise controls of environmental parameters, such as temperature, humidity, and light cycle, and the capability via complex programming to regulate these environmental parameters. But they are expensive. The high cost of maintaining a controlled growth environment is often a limiting factor when determining experiment size and feasibility. To overcome the limitation of commercial growth chambers, we designed and constructed an inexpensive plant growth chamber with consumer products for a material cost of $2,300. For a comparable growth space, a commercial plant growth chamber could cost $40,000 or more. Our plant growth chamber had outside dimensions of 1.5 m (W x 1.8 m (D x 2 m (H, providing a total growth area of 4.5 m2 with 40-cm high clearance. The dimensions of the growth area and height can be flexibly changed. Fluorescent lights with large reflectors provided a relatively spatially uniform photosynthetically active radiation intensity of 140-250 μmoles/m2/sec. A portable air conditioner provided an ample cooling capacity, and a cooling water mister acted as a powerful humidifier. Temperature, relative humidity, and light cycle inside the chamber were controlled via a z-wave home automation system, which allowed the environmental parameters to be monitored and programmed through the internet. In our setting, the temperature was tightly controlled: 22.2°C±0.8°C. The one-hour average relative humidity was maintained at 75%±7% with short spikes up to ±15%. Using the interaction between Arabidopsis and one of its bacterial pathogens as a test experimental system, we demonstrate that experimental results produced in our chamber were highly comparable to those obtained in a commercial growth chamber. In summary, our design of an inexpensive plant

  7. Passivation of MBE grown InGaSb/InAs superlattice photodiodes

    Science.gov (United States)

    Hill, Cory J.; Keo, Sam S.; Mumolo, Jason M.; Gunapala, Sarath D.

    2005-01-01

    We have performed wet chemical passivation tests on InGaSb/InAs superlattice photodiode structures grown molecular beam epitaxy. The details of the devices growth and characterization as well as the results of chemical passivation involving RuCl3 and H2SO4 with SiO2 dielectric depositions are presented.

  8. Microprocessor system to recover data from a self-scanning photodiode array

    International Nuclear Information System (INIS)

    Koppel, L.N.; Gadd, T.J.

    1975-01-01

    A microprocessor system developed at Lawrence Livermore Laboratory has expedited the recovery of data describing the low energy x-ray spectra radiated by laser-fusion targets. An Intel microprocessor controls the digitization and scanning of the data stream of an x-ray-sensitive self-scanning photodiode array incorporated in a crystal diffraction spectrometer

  9. A Novel Ring Shaped Photodiode for Reflectance Pulse Oximetry in Wireless Applications

    DEFF Research Database (Denmark)

    Duun, Sune; Haahr, Rasmus Grønbek; Birkelund, Karen

    2007-01-01

    gives optimal gathering of light and thereby enabling lower LED drive currents and lower power consumption. To further optimize the photodiode a two layer SiO2/SiN interference filter is employed yielding 98% transmission at the wavelengths of the LED and damping of other wavelengths. The presented...

  10. A Prototype RICH Detector Using Multi-Anode Photo Multiplier Tubes and Hybrid Photo-Diodes

    CERN Document Server

    Albrecht, E; Bibby, J H; Brook, N H; Doucas, G; Duane, A; Easo, S; Eklund, L; French, M; Gibson, V; Gys, Thierry; Halley, A W; Harnew, N; John, M; Piedigrossi, D; Rademacker, J; Simmons, B; Smale, N J; Teixeira-Dias, P; Toudup, L W; Websdale, David M; Wilkinson, G R; Wotton, S A

    2001-01-01

    The performance of a prototype Ring Imaging Cherenkov Detector is studied using a charged particle beam. The detector performance, using CF4 and air as radiators, is described. Cherenkov angle precision and photoelectron yield using hybrid photo-diodes and multi-anode PMTs agree with simulations and are assessed in terms of the requirements of the LHCb experiment.

  11. Scintillation detector composed by new type of avalanche photodiode and CsI(Tl) crystal

    International Nuclear Information System (INIS)

    He Jingtang; Chen Duanbao; Li Zuhao; Mao Yufang; Dong Xiaoli

    1996-01-01

    Using S5345 type of avalanche photodiode produced by Hamamatsu for the CsI(Tl) crystal readout, the spectrum of γ ray were measured. Energy resolution of 6.8% for 1.27 MeV γ ray from 22 Na source was obtained. The relation between energy resolution and coupling area, dimension of crystal, shaping time and bias were measured

  12. Study on the property of the avalanche photodiode as the readout component for scintillation crystals

    International Nuclear Information System (INIS)

    He Jingtang; Chen Duanbao; Zhu Guoyi; Mao Yufang; Dong Xiaoli; Li Zuhao

    1996-01-01

    The new avalanche photodiode (APD) and a CsI(Tl) crystal formed a scintillation detector. The energy spectrum of γ rays was measured by this detector. The measured results were compared with that measured by photomultiplier. Our plan is to use APD as PbWO 4 readout component for forward luminosity electromagnetic calorimeter at τ-C factory

  13. Multi-Layer Organic Squaraine-Based Photodiode for Indirect X-Ray Detection

    Science.gov (United States)

    Iacchetti, Antonio; Binda, Maddalena; Natali, Dario; Giussani, Mattia; Beverina, Luca; Fiorini, Carlo; Peloso, Roberta; Sampietro, Marco

    2012-10-01

    The paper presents an organic-based photodiode coupled to a CsI(Tl) scintillator to realize an X-ray detector. A suitable blend of an indolic squaraine derivative and of fullerene derivative has been used for the photodiode, thus allowing external quantum efficiency in excess of 10% at a wavelength of 570 nm, well matching the scintillator output spectrum. Thanks to the additional deposition of a 15 nm thin layer of a suitable low electron affinity polymer, carriers injection from the metal into the organic semiconductor has been suppressed, and dark current density as low as has been obtained, which is comparable to standard Si-based photodiodes. By using a collimated X-ray beam impinging onto the scintillator mounted over the photodiode we have been able to measure current variations in the order of 150 pA on a dark current floor of less than 50 pA when operating the X-ray tube in switching mode, thus proving the feasibility of indirect X-ray detection by means of organic semiconductors.

  14. Using the combination CsI(Tl) + photodiode for identification and energy measurement of light particles

    International Nuclear Information System (INIS)

    Guinet, D.; Chambon, B.; Cheynis, B.; Demeyer, A.; Drain, D.; Hu, X.C.; Pastor, C.; Vagneron, L.; Zaid, K.; Giorni, A.; Heuer, D.; Lleres, A.; Viano, J.B.

    1989-01-01

    The feasibility of discriminating light charged particles in charge and mass using the CsI(Tl) + photodiode combination is demonstrated. Experiment layout and results for a test using a beam of 30 MeV/nucleon α particles impinging on self-supporting gold and aluminium targets are shown

  15. HPLC-photodiode array detection analysis of curcuminoids in Curcuma species indigenous to Indonesia

    NARCIS (Netherlands)

    Bos, Rein; Windono, Tri; Woerdenbag, Herman J.; Boersma, Ykelien L.; Koulman, Albert; Kayser, Oliver

    An optimized HPLC method with photodiode array detection was developed and applied to analyse the curcuminoids curcumin, demethoxycurcumin, and bis-demethoxycurcumin in rhizomes of Curcuma mangga Val &. v. Zijp, C. heyneana Val. & v. Zijp, C. aeruginosa Roxb. and C. soloensis Val. (Zingiberaceae),

  16. Charge-Separation Dynamics in Inorganic-Organic Ternary Blends for Efficient Infrared Photodiodes

    NARCIS (Netherlands)

    Jarzab, Dorota; Szendrei, Krisztina; Yarema, Maksym; Pichler, Stefan; Heiss, Wolfgang; Loi, Maria A.

    2011-01-01

    Knowledge about the working mechanism of the PbS:P3HT:PCBM [P3HT=poly(3-hexylthiophene), PCBM=[6,6]-phenyl-C(61) -butyric acid methyl ester] hybrid blend used for efficient near-infrared photodiodes is obtained from time-resolved photoluminescence (PL) studies. To understand the role of each

  17. Photodiode area effect on performance of X-ray CMOS active pixel sensors

    Science.gov (United States)

    Kim, M. S.; Kim, Y.; Kim, G.; Lim, K. T.; Cho, G.; Kim, D.

    2018-02-01

    Compared to conventional TFT-based X-ray imaging devices, CMOS-based X-ray imaging sensors are considered next generation because they can be manufactured in very small pixel pitches and can acquire high-speed images. In addition, CMOS-based sensors have the advantage of integration of various functional circuits within the sensor. The image quality can also be improved by the high fill-factor in large pixels. If the size of the subject is small, the size of the pixel must be reduced as a consequence. In addition, the fill factor must be reduced to aggregate various functional circuits within the pixel. In this study, 3T-APS (active pixel sensor) with photodiodes of four different sizes were fabricated and evaluated. It is well known that a larger photodiode leads to improved overall performance. Nonetheless, if the size of the photodiode is > 1000 μm2, the degree to which the sensor performance increases as the photodiode size increases, is reduced. As a result, considering the fill factor, pixel-pitch > 32 μm is not necessary to achieve high-efficiency image quality. In addition, poor image quality is to be expected unless special sensor-design techniques are included for sensors with a pixel pitch of 25 μm or less.

  18. A portable, automated, inexpensive mass and balance calibration system

    International Nuclear Information System (INIS)

    Maxwell, S.L. III; Clark, J.P.

    1987-01-01

    Reliable mass measurements are essential for a nuclear production facility or process control laboratory. DOE Order 5630.2 requires that traceable standards be used to calibrate and monitor equipment used for nuclear material measurements. To ensure the reliability of mass measurements and to comply with DOE traceable requirements, a portable, automated mass and balance calibration system is used at the Savannah River Plant. Automation is achieved using an EPSON HX-20 notebook computer, which can be operated via RS232C interfacing to electronic balances or function with manual data entry if computer interfacing is not feasible. This economical, comprehensive, user-friendly system has three main functions in a mass measurement control program (MMCP): balance certification, calibration of mass standards, and daily measurement of traceable standards. The balance certification program tests for accuracy, precision, sensitivity, linearity, and cornerloading versus specific requirements. The mass calibration program allows rapid calibration of inexpensive mass standards traceable to certified Class S standards. This MMCP permits daily measurement of traceable standards to monitor the reliability of balances during routine use. The automated system verifies balance calibration, stores results for future use, and provides a printed control chart of the stored data. Another feature of the system permits three different weighing routines that accommodate our need for varying degrees of reliability in routine weighing operations. 1 ref

  19. Inexpensive multiplexed library preparation for megabase-sized genomes.

    Directory of Open Access Journals (Sweden)

    Michael Baym

    Full Text Available Whole-genome sequencing has become an indispensible tool of modern biology. However, the cost of sample preparation relative to the cost of sequencing remains high, especially for small genomes where the former is dominant. Here we present a protocol for rapid and inexpensive preparation of hundreds of multiplexed genomic libraries for Illumina sequencing. By carrying out the Nextera tagmentation reaction in small volumes, replacing costly reagents with cheaper equivalents, and omitting unnecessary steps, we achieve a cost of library preparation of $8 per sample, approximately 6 times cheaper than the standard Nextera XT protocol. Furthermore, our procedure takes less than 5 hours for 96 samples. Several hundred samples can then be pooled on the same HiSeq lane via custom barcodes. Our method will be useful for re-sequencing of microbial or viral genomes, including those from evolution experiments, genetic screens, and environmental samples, as well as for other sequencing applications including large amplicon, open chromosome, artificial chromosomes, and RNA sequencing.

  20. Enhancing COSMO-DE ensemble forecasts by inexpensive techniques

    Directory of Open Access Journals (Sweden)

    Zied Ben Bouallègue

    2013-02-01

    Full Text Available COSMO-DE-EPS, a convection-permitting ensemble prediction system based on the high-resolution numerical weather prediction model COSMO-DE, is pre-operational since December 2010, providing probabilistic forecasts which cover Germany. This ensemble system comprises 20 members based on variations of the lateral boundary conditions, the physics parameterizations and the initial conditions. In order to increase the sample size in a computationally inexpensive way, COSMO-DE-EPS is combined with alternative ensemble techniques: the neighborhood method and the time-lagged approach. Their impact on the quality of the resulting probabilistic forecasts is assessed. Objective verification is performed over a six months period, scores based on the Brier score and its decomposition are shown for June 2011. The combination of the ensemble system with the alternative approaches improves probabilistic forecasts of precipitation in particular for high precipitation thresholds. Moreover, combining COSMO-DE-EPS with only the time-lagged approach improves the skill of area probabilities for precipitation and does not deteriorate the skill of 2 m-temperature and wind gusts forecasts.

  1. A lightweight, inexpensive robotic system for insect vision.

    Science.gov (United States)

    Sabo, Chelsea; Chisholm, Robert; Petterson, Adam; Cope, Alex

    2017-09-01

    Designing hardware for miniaturized robotics which mimics the capabilities of flying insects is of interest, because they share similar constraints (i.e. small size, low weight, and low energy consumption). Research in this area aims to enable robots with similarly efficient flight and cognitive abilities. Visual processing is important to flying insects' impressive flight capabilities, but currently, embodiment of insect-like visual systems is limited by the hardware systems available. Suitable hardware is either prohibitively expensive, difficult to reproduce, cannot accurately simulate insect vision characteristics, and/or is too heavy for small robotic platforms. These limitations hamper the development of platforms for embodiment which in turn hampers the progress on understanding of how biological systems fundamentally work. To address this gap, this paper proposes an inexpensive, lightweight robotic system for modelling insect vision. The system is mounted and tested on a robotic platform for mobile applications, and then the camera and insect vision models are evaluated. We analyse the potential of the system for use in embodiment of higher-level visual processes (i.e. motion detection) and also for development of navigation based on vision for robotics in general. Optic flow from sample camera data is calculated and compared to a perfect, simulated bee world showing an excellent resemblance. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  2. A portable, automated, inexpensive mass and balance calibration system

    International Nuclear Information System (INIS)

    Maxwell, S.L. III; Clark, J.P.

    1987-01-01

    Reliable mass measurements are essential for a nuclear production facility or process control laboratory. DOE Order 5630.2 requires that traceable standards be used to calibrate and monitor equipment used for nuclear material measurements. To ensure the reliability of mass measurements and to comply with DOE traceability requirements, a portable, automated mass and balance calibration system is used at the Savannah River Plant. Automation is achieved using an EPSON HX-20 notebook computer, which can be operated via RS232C interfacing to electronic balances or function with manual data entry if computer interfacing is not feasible. This economical, comprehensive, user-friendly system has three main functions in a mass measurement control program (MMCP): balance certification, calibration of mass standards, and daily measurement of traceable standards. The balance certification program tests for accuracy, precision, sensitivity, linearity, and cornerloading versus specific requirements. The mass calibration program allows rapid calibration of inexpensive mass standards traceable to certified Class S standards. This MMCP permits daily measurement of traceable standards to monitor the reliability of balances during routine use. The automated system verifies balance calibration, stores results for future use, and provides a printed control chart of the stored data. Another feature of the system permits three different weighing routines that accommodate their need for varying degrees of reliability in routine weighing operations

  3. A simple and inexpensive method for genomic restriction mapping analysis

    International Nuclear Information System (INIS)

    Huang, C.H.; Lam, V.M.S.; Tam, J.W.O.

    1988-01-01

    The Southern blotting procedure for the transfer of DNA fragments from agarose gels to nitrocellulose membranes has revolutionized nucleic acid detection methods, and it forms the cornerstone of research in molecular biology. Basically, the method involves the denaturation of DNA fragments that have been separated on an agarose gel, the immobilization of the fragments by transfer to a nitrocellulose membrane, and the identification of the fragments of interest through hybridization to /sup 32/P-labeled probes and autoradiography. While the method is sensitive and applicable to both genomic and cloned DNA, it suffers from the disadvantages of being time consuming and expensive, and fragments of greater than 15 kb are difficult to transfer. Moreover, although theoretically the nitrocellulose membrane can be washed and hybridized repeatedly using different probes, in practice, the membrane becomes brittle and difficult to handle after a few cycles. A direct hybridization method for pure DNA clones was developed in 1975 but has not been widely exploited. The authors report here a modification of their procedure as applied to genomic DNA. The method is simple, rapid, and inexpensive, and it does not involve transfer to nitrocellulose membranes

  4. Ultraviolet /UV/ sensitive phosphors for silicon imaging detectors

    Science.gov (United States)

    Viehmann, W.; Cowens, M. W.; Butner, C. L.

    1981-01-01

    The fluorescence properties of UV sensitive organic phosphors and the radiometric properties of phosphor coated silicon detectors in the VUV, UV, and visible wavelengths are described. With evaporated films of coronene and liumogen, effective quantum efficiencies of up to 20% have been achieved on silicon photodiodes in the vacuum UV. With thin films of methylmethacrylate (acrylic), which are doped with organic laser dyes and deposited from solution, detector quantum efficiencies of the order of 15% for wavelengths of 120-165 nm and of 40% for wavelengths above 190 nm have been obtained. The phosphor coatings also act as antireflection coatings and thereby enhance the response of coated devices throughout the visible and near IR.

  5. Photoresponse analysis of the CMOS photodiodes for CMOS x-ray image sensor

    International Nuclear Information System (INIS)

    Kim, Young Soo; Ha, Jang Ho; Kim, Han Soo; Yeo, Sun Mok

    2012-01-01

    Although in the short term CMOS active pixel sensors (APSs) cannot compete with the conventionally used charge coupled devices (CCDs) for high quality scientific imaging, recent development in CMOS APSs indicate that CMOS performance level of CCDs in several domains. CMOS APSs possess thereby a number of advantages such as simpler driving requirements and low power operation. CMOS image sensors can be processed in standard CMOS technologies and the potential of on-chip integration of analog and digital circuitry makes them more suitable for several vision systems where system cost is of importance. Moreover, CMOS imagers can directly benefit from on-going technological progress in the field of CMOS technologies. Due to these advantages, the CMOS APSs are currently being investigated actively for various applications such as star tracker, navigation camera and X-ray imaging etc. In most detection systems, it is thought that the sensor is most important, since this decides the signal and noise level. So, in CMOS APSs, the pixel is very important compared to other functional blocks. In order to predict the performance of such image sensor, a detailed understanding of the photocurrent generation in the photodiodes that comprise the CMOS APS is required. In this work, we developed the analytical model that can calculate the photocurrent generated in CMOS photodiode comprising CMOS APSs. The photocurrent calculations and photo response simulations with respect to the wavelength of the incident photon were performed using this model for four types of photodiodes that can be fabricated in standard CMOS process. n + /p - sub and n + /p - epi/p - sub photodiode show better performance compared to n - well/p - sub and n - well/p - epi/p - sub due to the wider depletion width. Comparing n + /p - sub and n + /p - epi/p - sub photodiode, n + /p - sub has higher photo-responsivity in longer wavelength because of the higher electron diffusion current

  6. A new type photodiode: p-Si/GaN pn junction in series with GaN/Ag Schottky diode

    Energy Technology Data Exchange (ETDEWEB)

    Yakuphanoglu, F., E-mail: fyhanoglu@firat.edu.tr [Department of Physics, Faculty of Science, Firat University, Elazig (Turkey); Department of Physics, Faculty of Science, King Abdulaziz University, Jeddah (Saudi Arabia); Shokr, F.S. [Physics Department, Faculty of Science & Arts, King Abdulaziz University, Rabigh (Saudi Arabia); Gupta, R.K., E-mail: ramguptamsu@gmail.com [Department of Chemistry and Kansas Polymer Research Center, Pittsburg State University, Pittsburg (United States); Al-Ghamdi, Ahmed A. [Department of Physics, Faculty of Science, King Abdulaziz University, Jeddah (Saudi Arabia); Bin-Omran, S. [Department of Physics and Astronomy, College of Science, King Saud University, Riyadh (Saudi Arabia); Al-Turki, Yusuf [Department of Electrical and Computer Engineering, King Abdulaziz University, Jeddah (Saudi Arabia); El-Tantawy, Farid [Department of Physics, Faculty of Science, Suez Canal University, Ismailia (Egypt)

    2015-11-25

    Large quantities of gallium nitride (GaN) nanoparticles were successfully synthesized via a facile sol-gel approach. X-ray diffraction analysis confirms the polycrystalline nature of the GaN with hexagonal wurtzite structure and lattice constants a = 0.3189 nm and c = 0.5185 nm. The morphology of the GaN film was investigated by field emission scanning electron microscopy. The obtained results indicate that the synthesized GaN nanorods have an average length of around 60 nm and an average diameter of 23 nm. The optical band gap of the GaN film was obtained to be 3.4 eV. The gallium nitride/p-Si Schottky diode was fabricated by thermal evaporation technique on p-silicon. The current–voltage (I–V) characteristics of the fabricated diode was tested under dark and various light intensities. T The diode ideality factor and barrier height were computed using forward bias I–V characteristics of the diode and are found to be 1.66 and 0.53 eV, respectively. The obtained results suggest that the film preparation by sol gel method is fast and simple to prepare GaN based photodiode by according to metal organic deposition methods. - Highlights: • Facile method was used to synthesize GaN powder. • The Al/p-Si/GaN/Ag diode was fabricated using thermal evaporator technique. • Al/p-Si/GaN/Ag diode can be used as a photosensor for optoelectronic applications.

  7. Streamlined, Inexpensive 3D Printing of the Brain and Skull.

    Science.gov (United States)

    Naftulin, Jason S; Kimchi, Eyal Y; Cash, Sydney S

    2015-01-01

    Neuroimaging technologies such as Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) collect three-dimensional data (3D) that is typically viewed on two-dimensional (2D) screens. Actual 3D models, however, allow interaction with real objects such as implantable electrode grids, potentially improving patient specific neurosurgical planning and personalized clinical education. Desktop 3D printers can now produce relatively inexpensive, good quality prints. We describe our process for reliably generating life-sized 3D brain prints from MRIs and 3D skull prints from CTs. We have integrated a standardized, primarily open-source process for 3D printing brains and skulls. We describe how to convert clinical neuroimaging Digital Imaging and Communications in Medicine (DICOM) images to stereolithography (STL) files, a common 3D object file format that can be sent to 3D printing services. We additionally share how to convert these STL files to machine instruction gcode files, for reliable in-house printing on desktop, open-source 3D printers. We have successfully printed over 19 patient brain hemispheres from 7 patients on two different open-source desktop 3D printers. Each brain hemisphere costs approximately $3-4 in consumable plastic filament as described, and the total process takes 14-17 hours, almost all of which is unsupervised (preprocessing = 4-6 hr; printing = 9-11 hr, post-processing = Printing a matching portion of a skull costs $1-5 in consumable plastic filament and takes less than 14 hr, in total. We have developed a streamlined, cost-effective process for 3D printing brain and skull models. We surveyed healthcare providers and patients who confirmed that rapid-prototype patient specific 3D models may help interdisciplinary surgical planning and patient education. The methods we describe can be applied for other clinical, research, and educational purposes.

  8. Streamlined, Inexpensive 3D Printing of the Brain and Skull.

    Directory of Open Access Journals (Sweden)

    Jason S Naftulin

    Full Text Available Neuroimaging technologies such as Magnetic Resonance Imaging (MRI and Computed Tomography (CT collect three-dimensional data (3D that is typically viewed on two-dimensional (2D screens. Actual 3D models, however, allow interaction with real objects such as implantable electrode grids, potentially improving patient specific neurosurgical planning and personalized clinical education. Desktop 3D printers can now produce relatively inexpensive, good quality prints. We describe our process for reliably generating life-sized 3D brain prints from MRIs and 3D skull prints from CTs. We have integrated a standardized, primarily open-source process for 3D printing brains and skulls. We describe how to convert clinical neuroimaging Digital Imaging and Communications in Medicine (DICOM images to stereolithography (STL files, a common 3D object file format that can be sent to 3D printing services. We additionally share how to convert these STL files to machine instruction gcode files, for reliable in-house printing on desktop, open-source 3D printers. We have successfully printed over 19 patient brain hemispheres from 7 patients on two different open-source desktop 3D printers. Each brain hemisphere costs approximately $3-4 in consumable plastic filament as described, and the total process takes 14-17 hours, almost all of which is unsupervised (preprocessing = 4-6 hr; printing = 9-11 hr, post-processing = <30 min. Printing a matching portion of a skull costs $1-5 in consumable plastic filament and takes less than 14 hr, in total. We have developed a streamlined, cost-effective process for 3D printing brain and skull models. We surveyed healthcare providers and patients who confirmed that rapid-prototype patient specific 3D models may help interdisciplinary surgical planning and patient education. The methods we describe can be applied for other clinical, research, and educational purposes.

  9. Streamlined, Inexpensive 3D Printing of the Brain and Skull

    Science.gov (United States)

    Cash, Sydney S.

    2015-01-01

    Neuroimaging technologies such as Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) collect three-dimensional data (3D) that is typically viewed on two-dimensional (2D) screens. Actual 3D models, however, allow interaction with real objects such as implantable electrode grids, potentially improving patient specific neurosurgical planning and personalized clinical education. Desktop 3D printers can now produce relatively inexpensive, good quality prints. We describe our process for reliably generating life-sized 3D brain prints from MRIs and 3D skull prints from CTs. We have integrated a standardized, primarily open-source process for 3D printing brains and skulls. We describe how to convert clinical neuroimaging Digital Imaging and Communications in Medicine (DICOM) images to stereolithography (STL) files, a common 3D object file format that can be sent to 3D printing services. We additionally share how to convert these STL files to machine instruction gcode files, for reliable in-house printing on desktop, open-source 3D printers. We have successfully printed over 19 patient brain hemispheres from 7 patients on two different open-source desktop 3D printers. Each brain hemisphere costs approximately $3–4 in consumable plastic filament as described, and the total process takes 14–17 hours, almost all of which is unsupervised (preprocessing = 4–6 hr; printing = 9–11 hr, post-processing = Printing a matching portion of a skull costs $1–5 in consumable plastic filament and takes less than 14 hr, in total. We have developed a streamlined, cost-effective process for 3D printing brain and skull models. We surveyed healthcare providers and patients who confirmed that rapid-prototype patient specific 3D models may help interdisciplinary surgical planning and patient education. The methods we describe can be applied for other clinical, research, and educational purposes. PMID:26295459

  10. Behaviour of large-area avalanche photodiodes under intense magnetic fields for VUV- visible- and X-ray photon detection

    International Nuclear Information System (INIS)

    Fernandes, L.M.P.; Antognini, A.; Boucher, M.; Conde, C.A.N.; Huot, O.; Knowles, P.; Kottmann, F.; Ludhova, L.; Mulhauser, F.; Pohl, R.; Schaller, L.A.; Santos, J.M.F. dos; Taqqu, D.; Veloso, J.F.C.A.

    2003-01-01

    The behaviour of large-area avalanche photodiodes for X-rays, visible and vacuum-ultra-violet (VUV) light detection in magnetic fields up to 5 T is described. For X-rays and visible light detection, the photodiode pulse amplitude and energy resolution were unaffected from 0 to 5 T, demonstrating the insensitivity of this type of detector to strong magnetic fields. For VUV light detection, however, the photodiode relative pulse amplitude decreases with increasing magnetic field intensity reaching a reduction of about 24% at 5 T, and the energy resolution degrades noticeably with increasing magnetic field

  11. Geochemistry of silicon isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Tiping; Li, Yanhe; Gao, Jianfei; Hu, Bin [Chinese Academy of Geological Science, Beijing (China). Inst. of Mineral Resources; Jiang, Shaoyong [China Univ. of Geosciences, Wuhan (China).

    2018-04-01

    Silicon is one of the most abundant elements in the Earth and silicon isotope geochemistry is important in identifying the silicon source for various geological bodies and in studying the behavior of silicon in different geological processes. This book starts with an introduction on the development of silicon isotope geochemistry. Various analytical methods are described and compared with each other in detail. The mechanisms of silicon isotope fractionation are discussed, and silicon isotope distributions in various extraterrestrial and terrestrial reservoirs are updated. Besides, the applications of silicon isotopes in several important fields are presented.

  12. Junction Transport in Epitaxial Film Silicon Heterojunction Solar Cells: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Young, D. L.; Li, J. V.; Teplin, C. W.; Stradins, P.; Branz, H. M.

    2011-07-01

    We report our progress toward low-temperature HWCVD epitaxial film silicon solar cells on inexpensive seed layers, with a focus on the junction transport physics exhibited by our devices. Heterojunctions of i/p hydrogenated amorphous Si (a-Si) on our n-type epitaxial crystal Si on n++ Si wafers show space-charge-region recombination, tunneling or diffusive transport depending on both epitaxial Si quality and the applied forward voltage.

  13. Micromachined silicon seismic accelerometer development

    Energy Technology Data Exchange (ETDEWEB)

    Barron, C.C.; Fleming, J.G.; Montague, S. [and others

    1996-08-01

    Batch-fabricated silicon seismic transducers could revolutionize the discipline of seismic monitoring by providing inexpensive, easily deployable sensor arrays. Our ultimate goal is to fabricate seismic sensors with sensitivity and noise performance comparable to short-period seismometers in common use. We expect several phases of development will be required to accomplish that level of performance. Traditional silicon micromachining techniques are not ideally suited to the simultaneous fabrication of a large proof mass and soft suspension, such as one needs to achieve the extreme sensitivities required for seismic measurements. We have therefore developed a novel {open_quotes}mold{close_quotes} micromachining technology that promises to make larger proof masses (in the 1-10 mg range) possible. We have successfully integrated this micromolding capability with our surface-micromachining process, which enables the formation of soft suspension springs. Our calculations indicate that devices made in this new integrated technology will resolve down to at least sub-{mu}G signals, and may even approach the 10{sup -10} G/{radical}Hz acceleration levels found in the low-earth-noise model.

  14. Silicon nanomaterials platform for bioimaging, biosensing, and cancer therapy.

    Science.gov (United States)

    Peng, Fei; Su, Yuanyuan; Zhong, Yiling; Fan, Chunhai; Lee, Shuit-Tong; He, Yao

    2014-02-18

    Silicon nanomaterials are an important class of nanomaterials with great potential for technologies including energy, catalysis, and biotechnology, because of their many unique properties, including biocompatibility, abundance, and unique electronic, optical, and mechanical properties, among others. Silicon nanomaterials are known to have little or no toxicity due to favorable biocompatibility of silicon, which is an important precondition for biological and biomedical applications. In addition, huge surface-to-volume ratios of silicon nanomaterials are responsible for their unique optical, mechanical, or electronic properties, which offer exciting opportunities for design of high-performance silicon-based functional nanoprobes, nanosensors, and nanoagents for biological analysis and detection and disease treatment. Moreover, silicon is the second most abundant element (after oxygen) on earth, providing plentiful and inexpensive resources for large-scale and low-cost preparation of silicon nanomaterials for practical applications. Because of these attractive traits, and in parallel with a growing interest in their design and synthesis, silicon nanomaterials are extensively investigated for wide-ranging applications, including energy, catalysis, optoelectronics, and biology. Among them, bioapplications of silicon nanomaterials are of particular interest. In the past decade, scientists have made an extensive effort to construct a silicon nanomaterials platform for various biological and biomedical applications, such as biosensors, bioimaging, and cancer treatment, as new and powerful tools for disease diagnosis and therapy. Nonetheless, there are few review articles covering these important and promising achievements to promote the awareness of development of silicon nanobiotechnology. In this Account, we summarize recent representative works to highlight the recent developments of silicon functional nanomaterials for a new, powerful platform for biological and

  15. Radiation profile measurements for edge transport barrier discharges in Compact Helical System using AXUV photodiode arrays

    International Nuclear Information System (INIS)

    Suzuki, C.; Okamura, S.; Minami, T.; Akiyama, T.; Fujisawa, A.; Ida, K.; Isobe, M.; Matsuoka, K.; Nagaoka, K.; Nishimura, S.; Peterson, B. J.; Shimizu, A.; Takahashi, C.; Toi, K.; Yoshimura, Y.

    2005-01-01

    The formation of edge transport barrier (ETB) has recently been found in Compact Helical System (CHS) plasmas heated by co-injected neutral beam injection (NBI) with strong gas puffing. This regime is characterized by the appearance of the steep gradient of the electron density near the edge following the abrupt drop of hydrogen Balmer alpha (H α ) line intensity. In addition to single channel pyroelectric detector as a conventional bolometer, we have employed unfiltered absolute extreme ultraviolet (AXUV) photodiode arrays as a simple and low-cost diagnostic to investigate spatial and temporal variations of radiation emissivity in the ETB discharges. A compact mounting module for a 20 channel AXUV photodiode array including an in-vacuum preamplifier for immediate current-voltage conversion has successfully been designed and fabricated. Two identical modules installed in the upper and lower viewports provide 40 lines of sight covering the inboard and outboard sides within the horizontally elongated cross section of the CHS plasma with wide viewing angle. Although spectral uniformity of the detector sensitivity of the AXUV photodiode is unsatisfied for photon energies lower than 200 eV, it has been confirmed that the signals of AXUV photodiode and pyroelectric detector in the ETB discharges show roughly the same behavior except for the very beginning and end of the discharges. The results of the measurements in typical ETB discharges show that the signals of all the channels of the AXUV photodiode arrays begin to increase more rapidly at the moment of the transition than before. The rate of the increase is larger for the edge viewing chords than for the center viewing ones, which indicates the flattening of the radiation profile following the change in the electron density profile after the formation of the ETB. However, the signals for the edge chords tend to saturate after several tens of milliseconds, while they still continue to increase for the central chords

  16. Single Photon Counting UV Solar-Blind Detectors Using Silicon and III-Nitride Materials

    Science.gov (United States)

    Nikzad, Shouleh; Hoenk, Michael; Jewell, April D.; Hennessy, John J.; Carver, Alexander G.; Jones, Todd J.; Goodsall, Timothy M.; Hamden, Erika T.; Suvarna, Puneet; Bulmer, J.; Shahedipour-Sandvik, F.; Charbon, Edoardo; Padmanabhan, Preethi; Hancock, Bruce; Bell, L. Douglas

    2016-01-01

    Ultraviolet (UV) studies in astronomy, cosmology, planetary studies, biological and medical applications often require precision detection of faint objects and in many cases require photon-counting detection. We present an overview of two approaches for achieving photon counting in the UV. The first approach involves UV enhancement of photon-counting silicon detectors, including electron multiplying charge-coupled devices and avalanche photodiodes. The approach used here employs molecular beam epitaxy for delta doping and superlattice doping for surface passivation and high UV quantum efficiency. Additional UV enhancements include antireflection (AR) and solar-blind UV bandpass coatings prepared by atomic layer deposition. Quantum efficiency (QE) measurements show QE > 50% in the 100–300 nm range for detectors with simple AR coatings, and QE ≅ 80% at ~206 nm has been shown when more complex AR coatings are used. The second approach is based on avalanche photodiodes in III-nitride materials with high QE and intrinsic solar blindness. PMID:27338399

  17. Development of Inexpensive, Efficient and Non-Toxic Thermoelectric Materials

    Science.gov (United States)

    Gali, Anand Pratik

    In the wake of the impending climate change challenges, it is highly necessary to reevaluate our energy utilization technologies and ensure their efficient operation. Fossil fuel powered power-plants account for the majority of the energy production in the United States. With an average efficiency not exceeding 40%, these fossil fuel power plants dissipate exorbitant amounts of wasted heat. One of the ways of making such energy conversion processes more efficient is by incorporating technologies that can harvest this scavenge heat. One of the ways of achieving this is by the use of thermoelectric (TE) materials, which utilize the Seebeck effect to convert thermal gradient into potential difference. Therefore, our research project focusses on development of TE materials, which are inexpensive, efficient, and non-toxic. Fe0.50V0.25Al0.25 is a narrow band-gap semiconductor, ideal for TE applications. Unlike the current market leader Bi0.4Te0.6, Fe0.50V0.25 Al0.25 contains earth abundant and non-toxic constituents making it viable for commercial production. Nevertheless, the TE efficiency, ZT, of Fe0.50V0.25Al0.25 is limited by its high thermal conductivity. Therefore, the goal of the current research is two-fold. Firstly, to design and fabricate apparatus for performing TE characterization on bulk materials. For this purpose, two sets of apparatus were designed and fabricated for measuring high temperature Seebeck coefficient and electrical resistivity. Secondly, to study the influence of doping on TE properties of Fe0.50V0.25Al0.25 alloy. In order to achieve this, vanadium in Fe0.50V0.25Al0.25 was substituted with dopants like Ti, Cr, Zr, W, Nb, Ta. This led to a 20 times improvement in ZT, from the baseline Fe0.50V0.25Al0.25, by effectively reducing the thermal conductivity and increasing the Seebeck coefficient.

  18. Inexpensive Open-Source Data Logging in the Field

    Science.gov (United States)

    Wickert, A. D.

    2013-12-01

    I present a general-purpose open-source field-capable data logger, which provides a mechanism to develop dense networks of inexpensive environmental sensors. This data logger was developed as a low-power variant of the Arduino open-source development system, and is named the ALog ("Arduino Logger") BottleLogger (it is slim enough to fit inside a Nalgene water bottle) version 1.0. It features an integrated high-precision real-time clock, SD card slot for high-volume data storage, and integrated power switching. The ALog can interface with sensors via six analog/digital pins, two digital pins, and one digital interrupt pin that can read event-based inputs, such as those from a tipping-bucket rain gauge. We have successfully tested the ALog BottleLogger with ultrasonic rangefinders (for water stage and snow accumulation and melt), temperature sensors, tipping-bucket rain gauges, soil moisture and water potential sensors, resistance-based tools to measure frost heave, and cameras that it triggers based on events. The source code for the ALog, including functions to interface with a a range of commercially-available sensors, is provided as an Arduino C++ library with example implementations. All schematics, circuit board layouts, and source code files are open-source and freely available under GNU GPL v3.0 and Creative Commons Attribution-ShareAlike 3.0 Unported licenses. Through this work, we hope to foster a community-driven movement to collect field environmental data on a budget that permits citizen-scientists and researchers from low-income countries to collect the same high-quality data as researchers in wealthy countries. These data can provide information about global change to managers, governments, scientists, and interested citizens worldwide. Watertight box with ALog BottleLogger data logger on the left and battery pack with 3 D cells on the right. Data can be collected for 3-5 years on one set of batteries.

  19. Geneva University - Silicon photomultiplier : features and applications

    CERN Multimedia

    Université de Genève

    2012-01-01

    GENEVA UNIVERSITY École de physique Département de physique nucléaire et corspusculaire 24, quai Ernest-Ansermet 1211 Genève 4 Tél.: (022) 379 62 73 Fax: (022) 379 69 92   Wednesday 7 March 2012 SEMINAIRE DE PHYSIQUE CORPUSCULAIRE 11.15 a.m. - Science II, Auditoire 1S081, 30, quai Ernest-Ansermet, 1211 Genève 4 SILICON PHOTOMULTIPLIER : FEATURES AND APPLICATIONS Dr Giulio SARACINO   University of Naples, Federico II   Silicon photomultipliers were developed about ten years ago and their use, unlike traditional photomultiplier tubes, is increasing more and more. They are an evolution of the avalanche photodiode working in Geiger mode regime. Hundreds of such diodes are connected in parallel, allowing single photon response, high detection efficiency, high gain at low bias voltage and very good timing performance. In spite of their Geiger regime, they can be considered linear devices, until the number of photon...

  20. Improved SPICE electrical model of silicon photomultipliers

    Energy Technology Data Exchange (ETDEWEB)

    Marano, D., E-mail: davide.marano@oact.inaf.it [INAF, Osservatorio Astrofisico di Catania, Via S. Sofia 78, I-95123 Catania (Italy); Bonanno, G.; Belluso, M.; Billotta, S.; Grillo, A.; Garozzo, S.; Romeo, G. [INAF, Osservatorio Astrofisico di Catania, Via S. Sofia 78, I-95123 Catania (Italy); Catalano, O.; La Rosa, G.; Sottile, G.; Impiombato, D.; Giarrusso, S. [INAF, Istituto di Astrofisica Spaziale e Fisica Cosmica di Palermo, Via U. La Malfa 153, I-90146 Palermo (Italy)

    2013-10-21

    The present work introduces an improved SPICE equivalent electrical model of silicon photomultiplier (SiPM) detectors, in order to simulate and predict their transient response to avalanche triggering events. In particular, the developed circuit model provides a careful investigation of the magnitude and timing of the read-out signals and can therefore be exploited to perform reliable circuit-level simulations. The adopted modeling approach is strictly related to the physics of each basic microcell constituting the SiPM device, and allows the avalanche timing as well as the photodiode current and voltage to be accurately simulated. Predictive capabilities of the proposed model are demonstrated by means of experimental measurements on a real SiPM detector. Simulated and measured pulses are found to be in good agreement with the expected results. -- Highlights: • An improved SPICE electrical model of silicon photomultipliers is proposed. • The developed model provides a truthful representation of the physics of the device. • An accurate charge collection as a function of the overvoltage is achieved. • The adopted electrical model allows reliable circuit-level simulations to be performed. • Predictive capabilities of the adopted model are experimentally demonstrated.

  1. Highly Sensitive Switchable Heterojunction Photodiode Based on Epitaxial Bi2FeCrO6 Multiferroic Thin Films.

    Science.gov (United States)

    Huang, Wei; Chakrabartty, Joyprokash; Harnagea, Catalin; Gedamu, Dawit; Ka, Ibrahima; Chaker, Mohamed; Rosei, Federico; Nechache, Riad

    2018-04-18

    Perovskite multiferroic oxides are promising materials for the realization of sensitive and switchable photodiodes because of their favorable band gap (heterojunction was fabricated by pulsed laser deposition. The heterojunction photodiode exhibits a large ideality factor ( n = ∼5.0) and a response time as fast as 68 ms, thanks to the effective charge carrier transport and collection at the BFCO/SRO interface. The diode can switch direction when the electric polarization is reversed by an external voltage pulse. The time-resolved photoluminescence decay of the device measured at ∼500 nm demonstrates an ultrafast charge transfer (lifetime = ∼6.4 ns) in BFCO/SRO heteroepitaxial structures. The estimated responsivity value at 500 nm and zero bias is 0.38 mA W -1 , which is so far the highest reported for any FE thin film photodiode. Our work highlights the huge potential for using multiferroic oxides to fabricate highly sensitive and switchable photodiodes.

  2. Proof-of-concept and feasibility demonstrations for an avalanche photodiode/photoelastic modulator-based imaging polarimeter

    Data.gov (United States)

    National Aeronautics and Space Administration — Building on the successful heritage of JPL’s Multiangle SpectroPolarimetric Imager (MSPI), we propose infusing HgCdTe avalanche photodiode (APD) array technology...

  3. Surface passivation of GaInAsSb photodiodes with thioacetamide

    Energy Technology Data Exchange (ETDEWEB)

    Salesse, A.; Joullie, A.; Chevrier, F.; Cuminal, Y.; Ferblantier, G.; Christol, P. [Institut d' Electronique du Sud (IES-CEM2), UMR CNRS 5507, Case 067, Universite Montpellier 2, 34 095 Montpellier Cedex 05 (France); Calas, P. [UMR CNRS 5073 CHIMIE, Case 017, Universite Montpellier 2, 34 095 Montpellier Cedex 05 (France); Nieto, J. [Instituto de Investigacion en Comunicacion Optica (IICO), Universidad Autonoma de San Luis Potosi, Alvaro Obregon 64, San Luis Potosi (Mexico)

    2007-04-15

    AlGaAsSb/GaInAsSb heterojunction mesa photodiodes having 2.2 {mu}m cutoff wavelength, grown by MBE on (p) GaSb substrates, have been passivated using thioacetamide CH{sub 4}CSNH{sub 2} and ammonium sulphide (NH{sub 4}){sub 2}S. Superior characteristics were obtained from devices processed with thioacetamide in acid medium (pH=2.4). At room temperature the surface leakage currents were suppressed, and the photodiodes showed R{sub 0}A product as high as 16 {omega}cm{sup 2} and detectivity D{sup *}(2 {mu}m,0 V){proportional_to}10{sup 10} cmHz{sup 1/2}W{sup -1}. A model explaining sulfuration mechanisms with thioacetamide and (NH{sub 4}){sub 2}S is proposed. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  4. Feasibility study of photodiodes utilization in the soil-moisture determination by gamma transmission

    International Nuclear Information System (INIS)

    Santos, L.A.P. dos.

    1992-08-01

    This study was done to verify the viability of photodiodes, as gamma radiation detector ( 241 Am - Energy=60 KeV), to measure soil water content. The photodiodes used had different mechanical and electrical characteristics, and were tested on soils of different textures. A good linear correlation between the logarithm of the attenuation factor and soil-moisture demonstrated such viability, and that the low photopeak efficiency of these devices is not a limitation to the measurement of soil water content. Furthermore, the stability, the portability, and low cost of such semiconductor devices, including its electronic system, represent relevant characteristics that may justify the development of a reliable gamma meter system for field studies. (author). 37 refs, 21 figs, 20 tabs

  5. Wet etching and chemical polishing of InAs/GaSb superlattice photodiodes

    International Nuclear Information System (INIS)

    Chaghi, R; Cervera, C; Aït-Kaci, H; Grech, P; Rodriguez, J B; Christol, P

    2009-01-01

    In this paper, we studied wet chemical etching fabrication of the InAs/GaSb superlattice mesa photodiode for the mid-infrared region. The details of the wet chemical etchants used for the device process are presented. The etching solution is based on orthophosphoric acid (H 3 PO 4 ), citric acid (C 6 H 8 O 7 ) and H 2 O 2 , followed by chemical polishing with the sodium hypochlorite (NaClO) solution and protection with photoresist polymerized. The photodiode performance is evaluated by current–voltage measurements. The zero-bias resistance area product R 0 A above 4 × 10 5 Ω cm 2 at 77 K is reported. The device did not show dark current degradation at 77 K after exposition during 3 weeks to the ambient air

  6. Setting best practice criteria for self-differencing avalanche photodiodes in quantum key distribution

    Science.gov (United States)

    Koehler-Sidki, Alexander; Dynes, James F.; Lucamarini, Marco; Roberts, George L.; Sharpe, Andrew W.; Savory, Seb J.; Yuan, Zhiliang; Shields, Andrew J.

    2017-10-01

    In recent years, the security of avalanche photodiodes as single photon detectors for quantum key distribution has been subjected to much scrutiny. The most prominent example of this surrounds the vulnerability of such devices to blinding under strong illumination. We focus on self-differencing avalanche photodiodes, single photon detectors that have demonstrated count rates exceeding 1 GCounts/s resulting in secure key rates over 1 MBit/s. These detectors use a passive electronic circuit to cancel any periodic signals thereby enhancing detection sensitivity. However this intrinsic feature can be exploited by adversaries to gain control of the devices using illumination of a moderate intensity. Through careful experimental examinations, we define here a set of criteria for these detectors to avoid such attacks.

  7. Modified Single Photo-diode (MSPD) Detection Technique for SAC-OCDMA System

    Science.gov (United States)

    Abdulqader, Sarah G.; Fadhil, Hilal A.; Aljunid, S. A.

    2015-03-01

    In this paper, a new detection technique called modified single photo-diode (MSPD) detection for SAC-OCDMA system is proposed. The proposed system based on the single photo-diode (SPD) detection technique. The new detection technique is proposed to overcome the limitation of phase-induced intensity noise (PIIN) in SPD detection technique. However, the proposed detection is based on an optical hard limiter (OHL) followed by a SPD and a low-pass filter (LPF) in order to suppress the phase intensity noise (PIIN) at the receiver side. The results show that the MSPD detection based on OHL has a good performance even when the transmission distance is long, which is different from the case of SPD detection technique. Therefore, the MSPD detection technique is shown to be effective to improve the bit error rate (BER<10-9) and to suppress the noise in the practical optical fiber network.

  8. HgCdTe Avalanche Photodiode Detectors for Airborne and Spaceborne Lidar at Infrared Wavelengths

    Science.gov (United States)

    Sun, Xiaoli; Abshire, James B.; Beck, Jeffrey D.; Mitra, Pradip; Reiff, Kirk; Yang, Guangning

    2017-01-01

    We report results from characterizing the HgCdTe avalanche photodiode (APD) sensorchip assemblies (SCA) developed for lidar at infrared wavelength using the high density vertically integrated photodiodes (HDVIP) technique. These devices demonstrated high quantum efficiency, typically greater than 90 between 0.8 micrometers and the cut-off wavelength, greater than 600 APD gain, near unity excess noise factor, 6-10 MHz electrical bandwidth and less than 0.5 fW/Hz(exp.1/2) noise equivalent power (NEP). The detectors provide linear analog output with a dynamic range of 2-3 orders of magnitude at a fixed APD gain without averaging, and over 5 orders of magnitude by adjusting the APD and preamplifier gain settings. They have been successfully used in airborne CO2 and CH4 integrated path differential absorption (IPDA) lidar as a precursor for space lidar applications.

  9. Ageing tests of radiation damaged lasers and photodiodes for the CMS experiment at CERN

    CERN Document Server

    Gill, K; Batten, J; Cervelli, G; Grabit, R; Jensen, F; Troska, Jan K; Vasey, F

    2000-01-01

    The effects of thermally accelerated ageing in irradiated and unirradiated 1310 nm InGaAsP edge-emitting lasers and InGaAs p-i-n photodiodes are presented. 40 lasers (20 irradiated) and 30 photodiodes (19 irradiated) were aged for 4000 hours at 80 degrees C. Periodic measurements were made of laser threshold and efficiency, and p-i-n leakage current and photocurrent. There were no sudden failures and there was very little wearout related degradation in either unirradiated or irradiated sample groups. The results suggest that the tested devices have a sufficiently long lifetime to operate for at least 10 years inside the Compact Muon Solenoid experiment despite being exposed to a harsh radiation environment. (19 refs).

  10. Characterisation of Geiger-mode avalanche photodiodes for medical imaging applications

    Energy Technology Data Exchange (ETDEWEB)

    Britvitch, I. [Swiss Federal Institute of Technology, CH-8092 Zurich (Switzerland)]. E-mail: Ilia.britvitch@psi.ch; Johnson, I. [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Renker, D. [Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Stoykov, A. [Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Lorenz, E. [Swiss Federal Institute of Technology, CH-8092 Zurich (Switzerland); Max Planck Institute for Physics, 80805 Munich (Germany)

    2007-02-01

    Recently developed multipixel Geiger-mode avalanche photodiodes (G-APDs) are very promising candidates for the detection of light in medical imaging instruments (e.g. positron emission tomography) as well as in high-energy physics experiments and astrophysical applications. G-APDs are especially well suited for morpho-functional imaging (multimodality PET/CT, SPECT/CT, PET/MRI, SPECT/MRI). G-APDs have many advantages compared to conventional photosensors such as photomultiplier tubes because of their compact size, low-power consumption, high quantum efficiency and insensitivity to magnetic fields. Compared to avalanche photodiodes and PIN diodes, they are advantageous because of their high gain, reduced sensitivity to pick up and the so-called nuclear counter effect and lower noise. We present measurements of the basic G-APD characteristics: photon detection efficiency, gain, inter-cell crosstalk, dynamic range, recovery time and dark count rate.

  11. Characterisation of Geiger-mode avalanche photodiodes for medical imaging applications

    International Nuclear Information System (INIS)

    Britvitch, I.; Johnson, I.; Renker, D.; Stoykov, A.; Lorenz, E.

    2007-01-01

    Recently developed multipixel Geiger-mode avalanche photodiodes (G-APDs) are very promising candidates for the detection of light in medical imaging instruments (e.g. positron emission tomography) as well as in high-energy physics experiments and astrophysical applications. G-APDs are especially well suited for morpho-functional imaging (multimodality PET/CT, SPECT/CT, PET/MRI, SPECT/MRI). G-APDs have many advantages compared to conventional photosensors such as photomultiplier tubes because of their compact size, low-power consumption, high quantum efficiency and insensitivity to magnetic fields. Compared to avalanche photodiodes and PIN diodes, they are advantageous because of their high gain, reduced sensitivity to pick up and the so-called nuclear counter effect and lower noise. We present measurements of the basic G-APD characteristics: photon detection efficiency, gain, inter-cell crosstalk, dynamic range, recovery time and dark count rate

  12. Thermoluminescent accident dose reader with photodiode; Termoluminiscencni litalnik akcidentnih doz s fotodiodo

    Energy Technology Data Exchange (ETDEWEB)

    Miklavzic, U; Mihelic, M [Institut Jozef Stefan, Ljubljana (Yugoslavia)

    1982-07-01

    The field version of TL reader for accident dose region 0.01-20 Gy is described. For light detection, the thermostated photodiode was used permitting measurements at the ambient temperatures from -20 C degrees to 50 C degrees, and a new mode of the glow curve integration. Results can be presented as integral or peak values of the glow curve. The reader was adapted for dosemeters IJS-TLD08 from sintered CaF2:Mn pellets. (author)

  13. X-ray spectrometry with Peltier-cooled large area avalanche photodiodes

    International Nuclear Information System (INIS)

    Fernandes, L.M.P.; Lopes, J.A.M.; Santos, J.M.F. dos; Conde, C.A.N.

    2004-01-01

    Performance characteristics of the response of a Peltier-cooled large-area avalanche photodiode are investigated. Detector gain, energy linearity, energy resolution and minimum detectable energy are studied at different operation temperatures. Detector energy resolution and lowest detectable X-ray energy present a strong improvement as the operation temperature is reduced from 25 to 15 deg. C and slower improvements are achieved for temperatures below 10 deg. C

  14. Comparison between Conventional OCDMA and Subcarrier Multiplexing SAC OCDMA System Based on Single Photodiode Detection

    OpenAIRE

    Ahmad N. A. A; Junita M. N; Aljunid Syed Alwi; Che Beson Mohd Rashidi; Endut Rosdisham

    2017-01-01

    This paper demonstrates the comparison between conventional OCDMA system and subcarrier multiplexing (SCM) SAC-OCDMA system by applying Recursive Combinatorial (RC) code based on single photodiode detection (SPD). SPD is used in the receiver part to reduce the effect of multiple access interference (MAI) which contributes as a dominant noise in incoherent SAC-OCDMA systems. From this analysis, the performance of SCM OCDMA network could be improved by using lower data rates and higher received...

  15. High speed, wide dynamic range analog signal processing for avalanche photodiode

    CERN Document Server

    Walder, J P; Pangaud, P

    2000-01-01

    A wide dynamic range multi-gain analog transimpedance amplifier integrated circuit has been developed for avalanche photodiode signal processing. The 96 dB input dynamic range is divided into four ranges of 12-bits each in order to provide 40 MHz analog sampled data to a 12-bits ADC. This concept which has been integrated in both BiCMOS and full complementary bipolar technology along with fitted design techniques will be presented.

  16. High speed, wide dynamic range analog signal processing for avalanche photodiode

    International Nuclear Information System (INIS)

    Walder, J.P.; El Mamouni, Houmani; Pangaud, Patrick

    2000-01-01

    A wide dynamic range multi-gain analog transimpedance amplifier integrated circuit has been developed for avalanche photodiode signal processing. The 96 dB input dynamic range is divided into four ranges of 12-bits each in order to provide 40 MHz analog sampled data to a 12-bits ADC. This concept which has been integrated in both BiCMOS and full complementary bipolar technology along with fitted design techniques will be presented

  17. High speed, wide dynamic range analog signal processing for avalanche photodiode

    Energy Technology Data Exchange (ETDEWEB)

    Walder, J.P. E-mail: walder@in2p3.fr; El Mamouni, Houmani; Pangaud, Patrick

    2000-03-11

    A wide dynamic range multi-gain analog transimpedance amplifier integrated circuit has been developed for avalanche photodiode signal processing. The 96 dB input dynamic range is divided into four ranges of 12-bits each in order to provide 40 MHz analog sampled data to a 12-bits ADC. This concept which has been integrated in both BiCMOS and full complementary bipolar technology along with fitted design techniques will be presented.

  18. Bio-inspired nano-photodiode for Low Light, High Resolution and crosstalk-free CMOS image sensing

    KAUST Repository

    Saffih, Faycal

    2011-05-01

    Previous attempts have been devoted to mimic biological vision intelligence at the architectural system level. In this paper, a novel imitation of biological visual system intelligence is suggested, at the device level with the introduction of novel photodiode morphology. The proposed bio-inspired nanorod photodiode puts the depletion region length on the path of the incident photon instead of on its width, as the case is with the planar photodiodes. The depletion region has a revolving volume to increase the photodiode responsivity, and thus its photosensitivity. In addition, it can virtually boost the pixel fill factor (FF) above the 100% classical limit due to decoupling of its vertical sensing area from its limited planar circuitry area. Furthermore, the suggested nanorod photodiode photosensitivity is analytically proven to be higher than that of the planar photodiode. We also show semi-empirically that the responsivity of the suggested device varies linearly with its height; this important feature has been confirmed using Sentaurus simulation. The proposed nano-photorod is believed to meet the increasingly stringent High-Resolution-Low-Light (HRLL) detection requirements of the camera-phone and biomedical imaging markets. © 2011 IEEE.

  19. Optical and electrical characterization of AlGaN based Schottky photodiodes after annealing at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Ngoepe, PNM, E-mail: phuti.ngoepe@up.ac.za; Meyer, WE; Diale, M; Auret, FD; Schalkwyk, L van

    2014-04-15

    In this study a comparison is made between the optical and electrical properties of Ni/Au and Ni/Ir/Au Schottky photodiodes based on Al{sub 0.35}Ga{sub 0.65}N. The effects of inserting Ir between Ni and Au are of particular interest. The comparison in the properties is done after annealing the photodiodes at different temperatures in an argon gas ambient. The reverse current decreased with annealing temperature up to 400 °C for the Ni/Au Schottky photodiode and up to 500 °C for the Ni/Ir/Au photodiode. The Schottky barrier heights increased with increasing annealing temperature. The responsivity of the Ni/Au photodiode was higher than that of the Ni/Ir/Au photodiode. The transmission of the Ni/Au metal layer improved with increasing annealing temperature up to 500 °C and the best transmission of the Ni/Ir/Au metal layer was after 400 °C annealing.

  20. A sensitive ultraviolet light photodiode based on graphene-on-zinc oxide Schottky junction

    Directory of Open Access Journals (Sweden)

    Zhang Teng-Fei

    2016-11-01

    Full Text Available In this study, we present a simple ultraviolet (UV light photodiode by transferring a layer of graphene film on single-crystal ZnO substrate. The as-fabricated heterojunction exhibited typical rectifying behavior, with a Schottky barrier height of 0.623 eV. Further optoelectronic characterization revealed that the graphene-ZnO Schottky junction photodiode displayed obvious sensitivity to 365-nm light illumination with good reproducibility. The responsivity and photoconductive gain were estimated to be 3×104 A/W and 105, respectively, which were much higher than other ZnO nanostructure-based devices. In addition, it was found that the on/off ratio of the present device can be considerably improved from 2.09 to 12.1, when the device was passivated by a layer of AlOx film. These results suggest that the present simply structured graphene-ZnO UV photodiode may find potential application in future optoelectronic devices.

  1. A sensitive ultraviolet light photodiode based on graphene-on-zinc oxide Schottky junction

    Science.gov (United States)

    Zhang, Teng-Fei; Wu, Guo-An; Wang, Jiu-Zhen; Yu, Yong-Qiang; Zhang, Deng-Yue; Wang, Dan-Dan; Jiang, Jing-Bo; Wang, Jia-Mu; Luo, Lin-Bao

    2017-08-01

    In this study, we present a simple ultraviolet (UV) light photodiode by transferring a layer of graphene film on single-crystal ZnO substrate. The as-fabricated heterojunction exhibited typical rectifying behavior, with a Schottky barrier height of 0.623 eV. Further optoelectronic characterization revealed that the graphene-ZnO Schottky junction photodiode displayed obvious sensitivity to 365-nm light illumination with good reproducibility. The responsivity and photoconductive gain were estimated to be 3×104 A/W and 105, respectively, which were much higher than other ZnO nanostructure-based devices. In addition, it was found that the on/off ratio of the present device can be considerably improved from 2.09 to 12.1, when the device was passivated by a layer of AlOx film. These results suggest that the present simply structured graphene-ZnO UV photodiode may find potential application in future optoelectronic devices.

  2. Radiation tests of photodiodes for the ATLAS SCT and PIXEL opto- links

    CERN Document Server

    Hou, L S; Lee, S C; Su, D S; Teng, P K

    2005-01-01

    In previous research, epitaxial Si PIN photodiodes produced by Centronic which will be used in the ATLAS semiconductor tracker have been irradiated with 1 MeV neutrons and 24 GeV protons with fluences up to an equivalent of $10^{15}$ 1 MeV neutrons (1,2) . In this work 30 MeV proton beams were used to irradiate Centronic and Truelight epitaxial Si PIN diodes with accumulated fluences of up to 2.1 multiplied by $10^{14}$-30 MeV p $cm^{-2}$, an equivalent of 5.7 multiplied by $10^{14} cm^{-2}$ 1 MeV neutrons, to reach the pixel radiation environment. The responsivity was measured with different levels of fluence in order to study the responsivity behaviour of two different types of photodiodes. The responsivity behaviour of these two photodiodes was similar: a linear degradation at large fluences, greater than $10^{14}$ 30 MeV p $cm^{-2}$, but with different slopes. The response of the Centronic PIN diode showed a degradation to 73% after a proton fluence of $10^{13}$ p $cm^{-2}$ of 30 MeV and a linear degradat...

  3. A Single-Chip Solar Energy Harvesting IC Using Integrated Photodiodes for Biomedical Implant Applications.

    Science.gov (United States)

    Chen, Zhiyuan; Law, Man-Kay; Mak, Pui-In; Martins, Rui P

    2017-02-01

    In this paper, an ultra-compact single-chip solar energy harvesting IC using on-chip solar cell for biomedical implant applications is presented. By employing an on-chip charge pump with parallel connected photodiodes, a 3.5 × efficiency improvement can be achieved when compared with the conventional stacked photodiode approach to boost the harvested voltage while preserving a single-chip solution. A photodiode-assisted dual startup circuit (PDSC) is also proposed to improve the area efficiency and increase the startup speed by 77%. By employing an auxiliary charge pump (AQP) using zero threshold voltage (ZVT) devices in parallel with the main charge pump, a low startup voltage of 0.25 V is obtained while minimizing the reversion loss. A 4 V in gate drive voltage is utilized to reduce the conduction loss. Systematic charge pump and solar cell area optimization is also introduced to improve the energy harvesting efficiency. The proposed system is implemented in a standard 0.18- [Formula: see text] CMOS technology and occupies an active area of 1.54 [Formula: see text]. Measurement results show that the on-chip charge pump can achieve a maximum efficiency of 67%. With an incident power of 1.22 [Formula: see text] from a halogen light source, the proposed energy harvesting IC can deliver an output power of 1.65 [Formula: see text] at 64% charge pump efficiency. The chip prototype is also verified using in-vitro experiment.

  4. Buried oxide layer in silicon

    Science.gov (United States)

    Sadana, Devendra Kumar; Holland, Orin Wayne

    2001-01-01

    A process for forming Silicon-On-Insulator is described incorporating the steps of ion implantation of oxygen into a silicon substrate at elevated temperature, ion implanting oxygen at a temperature below 200.degree. C. at a lower dose to form an amorphous silicon layer, and annealing steps to form a mixture of defective single crystal silicon and polycrystalline silicon or polycrystalline silicon alone and then silicon oxide from the amorphous silicon layer to form a continuous silicon oxide layer below the surface of the silicon substrate to provide an isolated superficial layer of silicon. The invention overcomes the problem of buried isolated islands of silicon oxide forming a discontinuous buried oxide layer.

  5. Photoresponse analysis of the CMOS photodiodes for CMOS x-ray image sensor

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Soo; Ha, Jang Ho; Kim, Han Soo; Yeo, Sun Mok [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2012-11-15

    Although in the short term CMOS active pixel sensors (APSs) cannot compete with the conventionally used charge coupled devices (CCDs) for high quality scientific imaging, recent development in CMOS APSs indicate that CMOS performance level of CCDs in several domains. CMOS APSs possess thereby a number of advantages such as simpler driving requirements and low power operation. CMOS image sensors can be processed in standard CMOS technologies and the potential of on-chip integration of analog and digital circuitry makes them more suitable for several vision systems where system cost is of importance. Moreover, CMOS imagers can directly benefit from on-going technological progress in the field of CMOS technologies. Due to these advantages, the CMOS APSs are currently being investigated actively for various applications such as star tracker, navigation camera and X-ray imaging etc. In most detection systems, it is thought that the sensor is most important, since this decides the signal and noise level. So, in CMOS APSs, the pixel is very important compared to other functional blocks. In order to predict the performance of such image sensor, a detailed understanding of the photocurrent generation in the photodiodes that comprise the CMOS APS is required. In this work, we developed the analytical model that can calculate the photocurrent generated in CMOS photodiode comprising CMOS APSs. The photocurrent calculations and photo response simulations with respect to the wavelength of the incident photon were performed using this model for four types of photodiodes that can be fabricated in standard CMOS process. n{sup +}/p{sup -}sub and n{sup +}/p{sup -}epi/p{sup -}sub photodiode show better performance compared to n{sup -}well/p{sup -}sub and n{sup -}well/p{sup -}epi/p{sup -}sub due to the wider depletion width. Comparing n{sup +}/p{sup -}sub and n{sup +}/p{sup -}epi/p{sup -}sub photodiode, n{sup +}/p{sup -}sub has higher photo-responsivity in longer wavelength because of

  6. Simple and inexpensive microfluidic devices for the generation of monodisperse multiple emulsions

    KAUST Repository

    Li, Erqiang; Zhang, Jiaming; Thoroddsen, Sigurdur T

    2013-01-01

    of expensive apparatus and a complex manufacturing procedure. Here, we report the design and fabrication of simple and inexpensive microfluidic devices based on microscope glass slides and pulled glass capillaries, for generating monodisperse multiple emulsions

  7. Cherenkov luminescence measurements with digital silicon photomultipliers: a feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Ciarrocchi, Esther; Belcari, Nicola; Guerra, Alberto Del [Department of Physics, University of Pisa, Pisa (Italy); INFN, section of Pisa, Pisa (Italy); Cherry, Simon R. [Department of Biomedical Engineering, University of California, Davis, CA (United States); Lehnert, Adrienne; Hunter, William C. J.; McDougald, Wendy; Miyaoka, Robert S.; Kinahan, Paul E. [Department of Radiology, University of Washington, Seattle, WA (United States)

    2015-11-16

    A feasibility study was done to assess the capability of digital silicon photomultipliers to measure the Cherenkov luminescence emitted by a β source. Cherenkov luminescence imaging (CLI) is possible with a charge coupled device (CCD) based technology, but a stand-alone technique for quantitative activity measurements based on Cherenkov luminescence has not yet been developed. Silicon photomultipliers (SiPMs) are photon counting devices with a fast impulse response and can potentially be used to quantify β-emitting radiotracer distributions by CLI. In this study, a Philips digital photon counting (PDPC) silicon photomultiplier detector was evaluated for measuring Cherenkov luminescence. The PDPC detector is a matrix of avalanche photodiodes, which were read one at a time in a dark count map (DCM) measurement mode (much like a CCD). This reduces the device active area but allows the information from a single avalanche photodiode to be preserved, which is not possible with analog SiPMs. An algorithm to reject the noisiest photodiodes and to correct the measured count rate for the dark current was developed. The results show that, in DCM mode and at (10–13) °C, the PDPC has a dynamic response to different levels of Cherenkov luminescence emitted by a β source and transmitted through an opaque medium. This suggests the potential for this approach to provide quantitative activity measurements. Interestingly, the potential use of the PDPC in DCM mode for direct imaging of Cherenkov luminescence, as a opposed to a scalar measurement device, was also apparent. We showed that a PDPC tile in DCM mode is able to detect and image a β source through its Cherenkov radiation emission. The detector’s dynamic response to different levels of radiation suggests its potential quantitative capabilities, and the DCM mode allows imaging with a better spatial resolution than the conventional event-triggered mode. Finally, the same acquisition procedure and data processing could

  8. Cherenkov luminescence measurements with digital silicon photomultipliers: a feasibility study

    International Nuclear Information System (INIS)

    Ciarrocchi, Esther; Belcari, Nicola; Guerra, Alberto Del; Cherry, Simon R.; Lehnert, Adrienne; Hunter, William C. J.; McDougald, Wendy; Miyaoka, Robert S.; Kinahan, Paul E.

    2015-01-01

    A feasibility study was done to assess the capability of digital silicon photomultipliers to measure the Cherenkov luminescence emitted by a β source. Cherenkov luminescence imaging (CLI) is possible with a charge coupled device (CCD) based technology, but a stand-alone technique for quantitative activity measurements based on Cherenkov luminescence has not yet been developed. Silicon photomultipliers (SiPMs) are photon counting devices with a fast impulse response and can potentially be used to quantify β-emitting radiotracer distributions by CLI. In this study, a Philips digital photon counting (PDPC) silicon photomultiplier detector was evaluated for measuring Cherenkov luminescence. The PDPC detector is a matrix of avalanche photodiodes, which were read one at a time in a dark count map (DCM) measurement mode (much like a CCD). This reduces the device active area but allows the information from a single avalanche photodiode to be preserved, which is not possible with analog SiPMs. An algorithm to reject the noisiest photodiodes and to correct the measured count rate for the dark current was developed. The results show that, in DCM mode and at (10–13) °C, the PDPC has a dynamic response to different levels of Cherenkov luminescence emitted by a β source and transmitted through an opaque medium. This suggests the potential for this approach to provide quantitative activity measurements. Interestingly, the potential use of the PDPC in DCM mode for direct imaging of Cherenkov luminescence, as a opposed to a scalar measurement device, was also apparent. We showed that a PDPC tile in DCM mode is able to detect and image a β source through its Cherenkov radiation emission. The detector’s dynamic response to different levels of radiation suggests its potential quantitative capabilities, and the DCM mode allows imaging with a better spatial resolution than the conventional event-triggered mode. Finally, the same acquisition procedure and data processing could

  9. Linear array of photodiodes to track a human speaker for video recording

    International Nuclear Information System (INIS)

    DeTone, D; Neal, H; Lougheed, R

    2012-01-01

    Communication and collaboration using stored digital media has garnered more interest by many areas of business, government and education in recent years. This is due primarily to improvements in the quality of cameras and speed of computers. An advantage of digital media is that it can serve as an effective alternative when physical interaction is not possible. Video recordings that allow for viewers to discern a presenter's facial features, lips and hand motions are more effective than videos that do not. To attain this, one must maintain a video capture in which the speaker occupies a significant portion of the captured pixels. However, camera operators are costly, and often do an imperfect job of tracking presenters in unrehearsed situations. This creates motivation for a robust, automated system that directs a video camera to follow a presenter as he or she walks anywhere in the front of a lecture hall or large conference room. Such a system is presented. The system consists of a commercial, off-the-shelf pan/tilt/zoom (PTZ) color video camera, a necklace of infrared LEDs and a linear photodiode array detector. Electronic output from the photodiode array is processed to generate the location of the LED necklace, which is worn by a human speaker. The computer controls the video camera movements to record video of the speaker. The speaker's vertical position and depth are assumed to remain relatively constant– the video camera is sent only panning (horizontal) movement commands. The LED necklace is flashed at 70Hz at a 50% duty cycle to provide noise-filtering capability. The benefit to using a photodiode array versus a standard video camera is its higher frame rate (4kHz vs. 60Hz). The higher frame rate allows for the filtering of infrared noise such as sunlight and indoor lighting–a capability absent from other tracking technologies. The system has been tested in a large lecture hall and is shown to be effective.

  10. Linear array of photodiodes to track a human speaker for video recording

    Science.gov (United States)

    DeTone, D.; Neal, H.; Lougheed, R.

    2012-12-01

    Communication and collaboration using stored digital media has garnered more interest by many areas of business, government and education in recent years. This is due primarily to improvements in the quality of cameras and speed of computers. An advantage of digital media is that it can serve as an effective alternative when physical interaction is not possible. Video recordings that allow for viewers to discern a presenter's facial features, lips and hand motions are more effective than videos that do not. To attain this, one must maintain a video capture in which the speaker occupies a significant portion of the captured pixels. However, camera operators are costly, and often do an imperfect job of tracking presenters in unrehearsed situations. This creates motivation for a robust, automated system that directs a video camera to follow a presenter as he or she walks anywhere in the front of a lecture hall or large conference room. Such a system is presented. The system consists of a commercial, off-the-shelf pan/tilt/zoom (PTZ) color video camera, a necklace of infrared LEDs and a linear photodiode array detector. Electronic output from the photodiode array is processed to generate the location of the LED necklace, which is worn by a human speaker. The computer controls the video camera movements to record video of the speaker. The speaker's vertical position and depth are assumed to remain relatively constant- the video camera is sent only panning (horizontal) movement commands. The LED necklace is flashed at 70Hz at a 50% duty cycle to provide noise-filtering capability. The benefit to using a photodiode array versus a standard video camera is its higher frame rate (4kHz vs. 60Hz). The higher frame rate allows for the filtering of infrared noise such as sunlight and indoor lighting-a capability absent from other tracking technologies. The system has been tested in a large lecture hall and is shown to be effective.

  11. Characterization of image converter tubes and photodiodes in the infrared region

    International Nuclear Information System (INIS)

    Fleurot, N.; Nail, M.; Verrecchia, R.; Clement, G.

    1979-01-01

    The detection of near infrared picosecond luminous events is of the highest interest in the laser fusion research. The temporal profile of the 1.06 μm laser pulse, has to be carefully measured with S1 streak cameras which present limitations in the picosecond range. We have undertaken measurement on S1 photodiodes to situate their fatigue threshold and try to understand the limitations of image converter tubes we also present the work undertaken at R.T.C./L.E.P. to produce stable and highly sensitive image converter tubes in the micron range with the ''transfer sensitization method''. (author)

  12. Ge-Based Spin-Photodiodes for Room-Temperature Integrated Detection of Photon Helicity

    KAUST Repository

    Rinaldi, Christian

    2012-05-02

    Spin-photodiodes based on Fe/MgO/Ge(001) heterostructures are reported. These devices perform the room-temperature integrated electrical detection of the spin polarization of a photocurrent generated by circularly polarized photons with a wavelength of 1300 nm, for light pulses with intensity I 0 down to 200 μW. A forward and reverse-biased average photocurrent variation of 5.9% is measured for the complete reversal of the incident light helicity. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Analysis of hybrid subcarrier multiplexing of OCDMA based on single photodiode detection

    Science.gov (United States)

    Ahmad, N. A. A.; Junita, M. N.; Aljunid, S. A.; Rashidi, C. B. M.; Endut, R.

    2017-11-01

    This paper analyzes the performance of subcarrier multiplexing (SCM) of spectral amplitude coding optical code multiple access (SAC-OCDMA) by applying Recursive Combinatorial (RC) code based on single photodiode detection (SPD). SPD is used in the receiver part to reduce the effect of multiple access interference (MAI) which contributes as a dominant noise in incoherent SAC-OCDMA systems. Results indicate that the SCM OCDMA network performance could be improved by using lower data rates and higher number of weight. Total number of users can also be enhanced by adding lower data rates and higher number of subcarriers.

  14. Cherenkov rings from aerogel detected by four large-area hybrid photodiodes

    International Nuclear Information System (INIS)

    Bellunato, T.; Braem, A.; Buzykaev, A.R.; Calvi, M.; Chesi, E.; Danilyuk, A.F.; Easo, S.; Jolly, S.; Joram, C.; Kravchenko, E.A.; Liko, D.; Matteuzzi, C.; Musy, M.; Negri, P.; Neufeld, N.; Onuchin, A.P.; Seguinot, J.; Wotton, S.

    2003-01-01

    We report on the results obtained using thick samples of silica aerogel as radiators for a Ring Imaging Cherenkov counter. Four large-diameter hybrid photodiodes with 2048 channels have been used as photon detectors. Pions and protons with momenta ranging from 6 to 10 GeV/c were separated and identified. The number of photoelectrons and the radius of the Cherenkov rings together with the Cherenkov angle resolution were measured. A comparison with a simulation program based on GEANT4 is discussed

  15. Behavioral electromagnetic models of high‐speed p‐i‐n photodiodes

    DEFF Research Database (Denmark)

    Jiang, Chenhui; Krozer, Viktor; Johansen, Tom Keinicke

    2011-01-01

    This article presents a methodology for developing small‐signal behavioral electromagnetic (EM) models of p‐i‐n photodiodes (PDs) for high‐speed applications. The EM model includes RC bandwidth limitation effect and transit‐time effect. The model is capable of accurately modeling arbitrary comple...... parasitics as well as extracting parasitic values and provide straightforward access to EM characteristics of devices. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:2530–2533, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26327...

  16. Analysis of hybrid subcarrier multiplexing of OCDMA based on single photodiode detection

    Directory of Open Access Journals (Sweden)

    Ahmad N. A. A

    2017-01-01

    Full Text Available This paper analyzes the performance of subcarrier multiplexing (SCM of spectral amplitude coding optical code multiple access (SAC-OCDMA by applying Recursive Combinatorial (RC code based on single photodiode detection (SPD. SPD is used in the receiver part to reduce the effect of multiple access interference (MAI which contributes as a dominant noise in incoherent SAC-OCDMA systems. Results indicate that the SCM OCDMA network performance could be improved by using lower data rates and higher number of weight. Total number of users can also be enhanced by adding lower data rates and higher number of subcarriers.

  17. A transimpedance amplifier for excess noise measurements of high junction capacitance avalanche photodiodes

    International Nuclear Information System (INIS)

    Green, James E; David, John P R; Tozer, Richard C

    2012-01-01

    This paper reports a novel and versatile system for measuring excess noise and multiplication in avalanche photodiodes (APDs), using a bipolar junction transistor based transimpedance amplifier front-end and based on phase-sensitive detection, which permits accurate measurement in the presence of a high dark current. The system can reliably measure the excess noise factor of devices with capacitance up to 5 nF. This system has been used to measure thin, large area Si pin APDs and the resulting data are in good agreement with measurements of the same devices obtained from a different noise measurement system which will be reported separately. (paper)

  18. State-of-the-art performance of GaAlAs/GaAs avalanche photodiodes

    Science.gov (United States)

    Law, H. D.; Nakano, K.; Tomasetta, L. R.

    1979-01-01

    Ga(0.15)Al(0.85)As/GaAs avalanche photodiodes have been successfully fabricated. The performance of these detectors is characterized by a rise time of less than 35 ps, an external quantum efficiency with an antireflection coating of 95% at 0.53 microns, and a microwave optical gain of 42 dB. The dark current density is in the low range (10 to the minus A/sq cm) at one-half the breakdown voltages, and rises to 0.0001 A/sq cm at 42 dB optical gain.

  19. Origin of large dark current increase in InGaAs/InP avalanche photodiode

    Science.gov (United States)

    Wen, J.; Wang, W. J.; Chen, X. R.; Li, N.; Chen, X. S.; Lu, W.

    2018-04-01

    The large dark current increase near the breakdown voltage of an InGaAs/InP avalanche photodiode is observed and analyzed from the aspect of bulk defects in the device materials. The trap level information is extracted from the temperature-dependent electrical characteristics of the device and the low temperature photoluminescence spectrum of the materials. Simulation results with the extracted trap level taken into consideration show that the trap is in the InP multiplication layer and the trap assisted tunneling current induced by the trap is the main cause of the large dark current increase with the bias from the punch-through voltage to 95% breakdown voltage.

  20. Silicon: electrochemistry and luminescence

    NARCIS (Netherlands)

    Kooij, Ernst Stefan

    1997-01-01

    The electrochemistry of crystalline and porous silicon and the luminescence from porous silicon has been studied. One chapter deals with a model for the anodic dissolution of silicon in HF solution. In following chapters both the electrochemistry and various ways of generating visible

  1. MUST: A silicon strip detector array for radioactive beam experiments

    CERN Document Server

    Blumenfeld, Y; Sauvestre, J E; Maréchal, F; Ottini, S; Alamanos, N; Barbier, A; Beaumel, D; Bonnereau, B; Charlet, D; Clavelin, J F; Courtat, P; Delbourgo-Salvador, P; Douet, R; Engrand, M; Ethvignot, T; Gillibert, A; Khan, E; Lapoux, V; Lagoyannis, A; Lavergne, L; Lebon, S; Lelong, P; Lesage, A; Le Ven, V; Lhenry, I; Martin, J M; Musumarra, A; Pita, S; Petizon, L; Pollacco, E; Pouthas, J; Richard, A; Rougier, D; Santonocito, D; Scarpaci, J A; Sida, J L; Soulet, C; Stutzmann, J S; Suomijärvi, T; Szmigiel, M; Volkov, P; Voltolini, G

    1999-01-01

    A new and innovative array, MUST, based on silicon strip technology and dedicated to the study of reactions induced by radioactive beams on light particles is described. The detector consists of 8 silicon strip - Si(Li) telescopes used to identify recoiling light charged particles through time of flight, energy loss and energy measurements and to determine precisely their scattering angle through X, Y position measurements. Each 60x60 mm sup 2 double sided silicon strip detector with 60 vertical and 60 horizontal strips yields an X-Y position resolution of 1 mm, an energy resolution of 50 keV, a time resolution of around 1 ns and a 500 keV energy threshold for protons. The backing Si(Li) detectors stop protons up to 25 MeV with a resolution of approximately 50 keV. CsI crystals read out by photo-diodes which stop protons up to 70 MeV are added to the telescopes for applications where higher energy particles need to be detected. The dedicated electronics in VXIbus standard allow us to house the 968 logic and a...

  2. Silicon heterojunction transistor

    International Nuclear Information System (INIS)

    Matsushita, T.; Oh-uchi, N.; Hayashi, H.; Yamoto, H.

    1979-01-01

    SIPOS (Semi-insulating polycrystalline silicon) which is used as a surface passivation layer for highly reliable silicon devices constitutes a good heterojunction for silicon. P- or B-doped SIPOS has been used as the emitter material of a heterojunction transistor with the base and collector of silicon. An npn SIPOS-Si heterojunction transistor showing 50 times the current gain of an npn silicon homojunction transistor has been realized by high-temperature treatments in nitrogen and low-temperature annealing in hydrogen or forming gas

  3. The chemistry of silicon

    CERN Document Server

    Rochow, E G; Emeléus, H J; Nyholm, Ronald

    1975-01-01

    Pergamon Texts in Organic Chemistry, Volume 9: The Chemistry of Silicon presents information essential in understanding the chemical properties of silicon. The book first covers the fundamental aspects of silicon, such as its nuclear, physical, and chemical properties. The text also details the history of silicon, its occurrence and distribution, and applications. Next, the selection enumerates the compounds and complexes of silicon, along with organosilicon compounds. The text will be of great interest to chemists and chemical engineers. Other researchers working on research study involving s

  4. Silicon Microspheres Photonics

    International Nuclear Information System (INIS)

    Serpenguzel, A.

    2008-01-01

    Electrophotonic integrated circuits (EPICs), or alternatively, optoelectronic integrated circuit (OEICs) are the natural evolution of the microelectronic integrated circuit (IC) with the addition of photonic capabilities. Traditionally, the IC industry has been based on group IV silicon, whereas the photonics industry on group III-V semiconductors. However, silicon based photonic microdevices have been making strands in siliconizing photonics. Silicon microspheres with their high quality factor whispering gallery modes (WGMs), are ideal candidates for wavelength division multiplexing (WDM) applications in the standard near-infrared communication bands. In this work, we will discuss the possibility of using silicon microspheres for photonics applications in the near-infrared

  5. Which Photodiode to Use: A Comparison of CMOS-Compatible Structures.

    Science.gov (United States)

    Murari, Kartikeya; Etienne-Cummings, Ralph; Thakor, Nitish; Cauwenberghs, Gert

    2009-07-01

    While great advances have been made in optimizing fabrication process technologies for solid state image sensors, the need remains to be able to fabricate high quality photosensors in standard CMOS processes. The quality metrics depend on both the pixel architecture and the photosensitive structure. This paper presents a comparison of three photodiode structures in terms of spectral sensitivity, noise and dark current. The three structures are n(+)/p-sub, n-well/p-sub and p(+)/n-well/p-sub. All structures were fabricated in a 0.5 mum 3-metal, 2-poly, n-well process and shared the same pixel and readout architectures. Two pixel structures were fabricated-the standard three transistor active pixel sensor, where the output depends on the photodiode capacitance, and one incorporating an in-pixel capacitive transimpedance amplifier where the output is dependent only on a designed feedback capacitor. The n-well/p-sub diode performed best in terms of sensitivity (an improvement of 3.5 x and 1.6 x over the n(+)/p-sub and p(+)/n-well/p-sub diodes, respectively) and signal-to-noise ratio (1.5 x and 1.2 x improvement over the n(+)/p-sub and p(+)/n-well/p-sub diodes, respectively) while the p(+)/n-well/p-sub diode had the minimum (33% compared to other two structures) dark current for a given sensitivity.

  6. Updated design for a low-noise, wideband transimpedance photodiode amplifier

    International Nuclear Information System (INIS)

    Paul, S. F.; Marsala, R.

    2006-01-01

    The high-speed rotation diagnostic developed for Columbia's HBT-EP tokamak requires a high quantum efficiency, very low drift detector/amplifier combination. An updated version of the circuit developed originally for the beam emission spectroscopy experiment on TFTR is being used. A low dark current (2 nA at 15 V bias), low input source capacitance (2 pF) FFD-040 N-type Si photodiode is operated in photoconductive mode. It has a quantum efficiency of 40% at the 468.6 nm (He II line that is being observed). A low-noise field-effect transistor (InterFET IFN152 with e Na =1.2 nV/√Hz) is used to reduce the noise in the transimpedance preamplifier (A250 AMPTEK op-amp) and a very high speed (unity-gain bandwidth=200 MHz) voltage feedback amplifier (LM7171) is used to restore the frequency response up to 100 kHz. This type of detector/amplifier is photon-noise limited at this bandwidth for incident light with a power of >∼2 nW. The circuit has been optimized using SIMETRIX 4.0 SPICE software and a prototype circuit has been tested successfully. Though photomultipliers and avalanche photodiodes can detect much lower light levels, for light levels >2 nW and a 10 kHz bandwidth, this detector/amplifier combination is more sensitive because of the absence of excess (internally generated) noise

  7. Organic semiconductor photodiode based on indigo carmine/n-Si for optoelectronic applications

    Science.gov (United States)

    Ganesh, V.; Manthrammel, M. Aslam; Shkir, Mohd.; Yahia, I. S.; Zahran, H. Y.; Yakuphanoglu, F.; AlFaify, S.

    2018-06-01

    The fabrication of indigo carmine/n-Si photodiode has been done, and a robust dark and photocurrent-voltage ( I- V), capacitance vs. voltage ( C-V) and conductance vs. voltage ( G-V) studies were done over a wide range of applied voltage and frequencies. The surface morphology was assessed by atomic force microscope (AFM), and the grain size was measured to be about 66 nm. The reverse current increased with both increasing illumination intensity and bias potential, whereas the forward current increased exponentially with bias potential. The responsivity value was also calculated. Barrier height and ideality factor of diode were estimated through a log (I) vs log (V) plot, and obtained to be 0.843 and 4.75 eV, respectively. The Vbi values are found between 0.95 and 1.2V for frequencies ranging between 100 kHz and 1 MHz. The value of R s is found to be lower at higher frequencies which may be due to a certain distribution of localized interface states. A strong frequency and voltage dependency were observed for interface states density N ss in the present indigo carmine/n-Si photodiode, and this explained the observed capacitance and resistance variation with frequency. These results suggest that the fabricated diode has the potential to be applied in optoelectronic devices.

  8. CsI(Tl) with photodiodes for identifying subsurface radionuclide contamination

    International Nuclear Information System (INIS)

    Stromswold, D.C.; Meisner, J.E.; Nicaise, W.F.

    1994-10-01

    At the US Department of Energy's Hanford Site near Richland, Washington, underground radioactive contamination exists as the result of leaks, spills, and intentional disposal of waste products from plutonium-production operations. Characterizing these contaminants in preparation for environmental remediation is a major effort now in progress. In this paper, a cylindrical (15 x 61 mm) CsI(Tl) scintillation detector with two side-mounted photodiodes has been developed to collect spectral gamma-ray data in subsurface contaminated formations at the U.S. Department of Energy's Hanford Site. It operates inside small-diameter, thick-wall steel pipes pushed into the ground to depths up to 20 m by a cone penetrometer. The detector provides a rugged, efficient, magnetic-field-insensitive means for identifying gamma-ray-emitting contaminants (mainly 137 Cs and 60 Co). Mounting two 3 x 30-mm photodiodes end-to-end on a flat area along the detector's side provides efficient light collection over the length of the detector

  9. Light emitting diode, photodiode-based fluorescence detection system for DNA analysis with microchip electrophoresis.

    Science.gov (United States)

    Hall, Gordon H; Glerum, D Moira; Backhouse, Christopher J

    2016-02-01

    Electrophoretic separation of fluorescently end-labeled DNA after a PCR serves as a gold standard in genetic diagnostics. Because of their size and cost, instruments for this type of analysis have had limited market uptake, particularly for point-of-care applications. This might be changed through a higher level of system integration and lower instrument costs that can be realized through the use of LEDs for excitation and photodiodes for detection--if they provide sufficient sensitivity. Here, we demonstrate an optimized microchip electrophoresis instrument using polymeric fluidic chips with fluorescence detection of end-labeled DNA with a LOD of 0.15 nM of Alexa Fluor 532. This represents orders of magnitude improvement over previously reported instruments of this type. We demonstrate the system with an electrophoretic separation of two PCR products and their respective primers. We believe that this is the first LED-induced fluorescence microchip electrophoresis system with photodiode-based detection that could be used for standard applications of PCR and electrophoresis. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Accelerated aging tests of radiation damaged lasers and photodiodes for the CMS tracker optical links

    CERN Document Server

    Gill, K; Batten, J; Cervelli, G; Grabit, R; Jensen, F; Troska, Jan K; Vasey, F

    1999-01-01

    The combined effects of radiation damage and accelerated ageing in COTS lasers and p-i-n photodiodes are presented. Large numbers of these devices are employed in future High Energy Physics experiments and it is vital that these devices are confirmed to be sufficiently robust in terms of both radiation resistance and reliability. Forty 1310 nm InGaAsP edge-emitting lasers (20 irradiated) and 30 InGaAs p- i-n photodiodes (19 irradiated) were aged for 4000 hours at 80 degrees C with periodic measurements made of laser threshold and efficiency, in addition to p-i-n leakage current and photocurrent. There were no sudden failures and there was very little wearout- related degradation in either unirradiated or irradiated sample groups. The results suggest that the tested devices have a sufficiently long lifetime to operate for at least 10 years inside the Compact Muon Solenoid experiment despite being exposed to a harsh radiation environment. (13 refs).

  11. Photodiode-based cutting interruption sensor for near-infrared lasers.

    Science.gov (United States)

    Adelmann, B; Schleier, M; Neumeier, B; Hellmann, R

    2016-03-01

    We report on a photodiode-based sensor system to detect cutting interruptions during laser cutting with a fiber laser. An InGaAs diode records the thermal radiation from the process zone with a ring mirror and optical filter arrangement mounted between a collimation unit and a cutting head. The photodiode current is digitalized with a sample rate of 20 kHz and filtered with a Chebyshev Type I filter. From the measured signal during the piercing, a threshold value is calculated. When the diode signal exceeds this threshold during cutting, a cutting interruption is indicated. This method is applied to sensor signals from cutting mild steel, stainless steel, and aluminum, as well as different material thicknesses and also laser flame cutting, showing the possibility to detect cutting interruptions in a broad variety of applications. In a series of 83 incomplete cuts, every cutting interruption is successfully detected (alpha error of 0%), while no cutting interruption is reported in 266 complete cuts (beta error of 0%). With this remarkable high detection rate and low error rate, the possibility to work with different materials and thicknesses in combination with the easy mounting of the sensor unit also to existing cutting machines highlight the enormous potential for this sensor system in industrial applications.

  12. An iterative method applied to optimize the design of PIN photodiodes for enhanced radiation tolerance and maximum light response

    International Nuclear Information System (INIS)

    Cedola, A.P.; Cappelletti, M.A.; Casas, G.; Peltzer y Blanca, E.L.

    2011-01-01

    An iterative method based on numerical simulations was developed to enhance the proton radiation tolerance and the responsivity of Si PIN photodiodes. The method allows to calculate the optimal values of the intrinsic layer thickness and the incident light wavelength, in function of the light intensity and the maximum proton fluence to be supported by the device. These results minimize the effects of radiation on the total reverse current of the photodiode and maximize its response to light. The implementation of the method is useful in the design of devices whose operation point should not suffer variations due to radiation.

  13. High photocurrent gain in NiO thin film/M-doped ZnO nanorods (M=Ag, Cd and Ni) heterojunction based ultraviolet photodiodes

    Energy Technology Data Exchange (ETDEWEB)

    Echresh, Ahmad, E-mail: ahmadechresh@gmail.com [Department of Science and Technology, Physical Electronics and Nanotechnology Division, Campus Norrköping, Linköping University, SE-601 74 Norrköping (Sweden); Echresh, Mohammad [Department of Physics, Sanati Hoveizeh University, Ahvaz (Iran, Islamic Republic of); Khranovskyy, Volodymyr [Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-5818358183 Linköping (Sweden); Nur, Omer; Willander, Magnus [Department of Science and Technology, Physical Electronics and Nanotechnology Division, Campus Norrköping, Linköping University, SE-601 74 Norrköping (Sweden)

    2016-10-15

    The thermal evaporation method has been used to deposit p-type NiO thin film, which was combined with hydrothermally grown n-type pure and M-doped ZnO nanorods (M=Ag, Cd and Ni) to fabricate a high performance p-n heterojunction ultraviolet photodiodes. The fabricated photodiodes show high rectification ratio and relatively low leakage current. The p-NiO/n-Zn{sub 0.94}Ag{sub 0.06}O heterojunction photodiode displays the highest photocurrent gain (~1.52×10{sup 4}), a photoresponsivity of ~4.48×10{sup 3} AW{sup −1} and a photosensitivity of ~13.56 compared with the other fabricated photodiodes. The predominated transport mechanisms of the p-n heterojunction ultraviolet photodiodes at low and high applied forward bias may be recombination-tunneling and space charge limited current, respectively.

  14. A new inexpensive customized plaque for choroidal melanoma iodine-125 plaque therapy

    International Nuclear Information System (INIS)

    Vine, A.K.; Tenhaken, R.K.; Diaz, R.F.; Maxson, B.B.; Lichter, A.S.

    1989-01-01

    The authors have developed a new inexpensive precious metal alloy plaque for use in customized iodine-125 plaque therapy. Each plaque is formed from two flat circular gold/palladium foils which are used in dental crown work. Using a simple manual mechanism, the two forms are stamped over a customized acrylic die shaped to the dimensions of the tumor base plus a 2-mm margin. Completed plaques consist of a back wall, a 2-mm side wall, and a 1.5-mm wide lip with holes for suture placement. Advantages include: simple construction from inexpensive components, customized shape, and iodine seeds that are readily visible on plane radiographs

  15. Electron Beam Induced Radiation Damage of the Semiconductor Radiation Detector based on Silicon

    International Nuclear Information System (INIS)

    Kim, Han Soo; Kim, Yong Kyun; Park, Se Hwan; Haa, Jang Ho; Kang, Sang Mook; Chung, Chong Eun; Cho, Seung Yeon; Park, Ji Hyun; Yoon, Tae Hyung

    2005-01-01

    A Silicon Surface Barrier (SSB) semiconductor detector which is generally used to detect a charged particle such as an alpha particle was developed. The performance of the developed SSB semiconductor detector was measured with an I-V curve and an alpha spectrum. The response for an alpha particle was measured by Pu-238 sources. A SSB semiconductor detector was irradiated firstly at 30sec, at 30μA and secondly 40sec, 40μA with a 2MeV pulsed electron beam generator in KAERI. And the electron beam induced radiation damage of a homemade SSB detector and the commercially available PIN photodiode were investigated. An annealing effect of the damaged SSB and PIN diode detector were also investigated using a Rapid Thermal Annealing (RTA). This data may assist in designing the silicon based semiconductor radiation detector when it is operated in a high radiation field such as space or a nuclear power plant

  16. Leakage current of amorphous silicon p-i-n diodes made by ion shower doping

    International Nuclear Information System (INIS)

    Kim, Hee Joon; Cho, Gyuseong; Choi, Joonhoo; Jung, Kwan-Wook

    2002-01-01

    In this letter, we report the leakage current of amorphous silicon (a-Si:H) p-i-n photodiodes, of which the p layer is formed by ion shower doping. The ion shower doping technique has an advantage over plasma-enhanced chemical vapor deposition (PECVD) in the fabrication of a large-area amorphous silicon flat-panel detector. The leakage current of the ion shower diodes shows a better uniformity within a 30 cmx40 cm substrate than that of the PECVD diodes. However, it shows a higher leakage current of 2-3 pA/mm 2 at -5 V. This high current originates from the high injection current at the p-i junction

  17. Measurement of synchrotron radiation from the NBS SURF II using a silicon radiometer

    International Nuclear Information System (INIS)

    Schaefer, A.R.

    1980-01-01

    A project is described in which the synchrotron radiation output from the NBS storage ring known as SURF II, is measured using a well characterized silicon based radiometer. This device consists of a silicon photodiode coupled with two interference filters to restrict the spectral response to a finite and convenient spectral region for the measurement. Considerations required for the characterization of the radiometer will be discussed. The absolute radiant flux from the storage ring is also calculable from various machine parameters. A measurement of the number of circulating electrons will be derived from electron counting techniques at low levels. This will yield an important intercomparison between the synchrotron flux measurements determined in two entirely different ways. (orig.)

  18. Modeling charge collection efficiency degradation in partially depleted GaAs photodiodes using the 1- and 2-carrier Hecht equations

    International Nuclear Information System (INIS)

    Auden, E.C.; Vizkelethy, G.; Serkland, D.K.; Bossert, D.J.; Doyle, B.L.

    2017-01-01

    The Hecht equation can be used to model the nonlinear degradation of charge collection efficiency (CCE) in response to radiation-induced displacement damage in both fully and partially depleted GaAs photodiodes. CCE degradation is measured for laser-generated photocurrent as a function of fluence and bias in Al_0_._3Ga_0_._7As/GaAs/Al_0_._2_5Ga_0_._7_5As p-i-n photodiodes which have been irradiated with 12 MeV C and 7.5 MeV Si ions. CCE is observed to degrade more rapidly with fluence in partially depleted photodiodes than in fully depleted photodiodes. When the intrinsic GaAs layer is fully depleted, the 2-carrier Hecht equation describes CCE degradation as photogenerated electrons and holes recombine at defect sites created by radiation damage in the depletion region. If the GaAs layer is partially depleted, CCE degradation is more appropriately modeled as the sum of the 2-carrier Hecht equation applied to electrons and holes generated within the depletion region and the 1-carrier Hecht equation applied to minority carriers that diffuse from the field-free (non-depleted) region into the depletion region. Enhanced CCE degradation is attributed to holes that recombine within the field-free region of the partially depleted intrinsic GaAs layer before they can diffuse into the depletion region.

  19. Analysis of taxines in Taxus plant material and cell cultures by hplc photodiode array and hplc-electrospray mass spectrometry

    NARCIS (Netherlands)

    Theodoridis, G.; Laskaris, G.; Rozendaal, E.L.M.; Verpoorte, R.

    2001-01-01

    A semi-purified Taxus baccata needles extract was analysed by RP-HPLC. More than 18 taxines and cinnamates were detected by photodiode array detection and LC-MS, 10 of them being positively identified. Furthermore, 10-deacetyl baccatin III (paclitaxel's main precursor) and other taxanes were also

  20. 16-element photodiode array for the angular microdeflection detector and for stabilization of a laser radiation direction

    Science.gov (United States)

    Wegrzecki, Maciej; Piotrowski, Tadeusz; Bar, Jan; Dobrowolski, Rafał; Klimov, Andrii; Klos, Helena; Marchewka, Michał; Nieprzecki, Marek; Panas, Andrzej; Prokaryn, Piotr; Seredyński, Bartłomiej; Sierakowski, Andrzej; Słysz, Wojciech; Szmigiel, Dariusz; Zaborowski, Michal

    2016-12-01

    In this paper, the design and technology of two types of 16-element photodiode arrays is described. The arrays were developed by the ITE and are to be used in detection of microdeflection of laser radiation at the Institute of Metrology and Biomedical Engineering in the Faculty of Mechatronics of Warsaw University of Technology. The electrical and photoelectrical parameters of the arrays are presented.

  1. X-ray imager using solution processed organic transistor arrays and bulk heterojunction photodiodes on thin, flexible plastic substrate

    NARCIS (Netherlands)

    Gelinck, G.H.; Kumar, A.; Moet, D.; Steen, J.L. van der; Shafique, U.; Malinowski, P.E.; Myny, K.; Rand, B.P.; Simon, M.; Rütten, W.; Douglas, A.; Jorritsma, J.; Heremans, P.L.; Andriessen, H.A.J.M.

    2013-01-01

    We describe the fabrication and characterization of large-area active-matrix X-ray/photodetector array of high quality using organic photodiodes and organic transistors. All layers with the exception of the electrodes are solution processed. Because it is processed on a very thin plastic substrate

  2. Modeling charge collection efficiency degradation in partially depleted GaAs photodiodes using the 1- and 2-carrier Hecht equations

    Energy Technology Data Exchange (ETDEWEB)

    Auden, E.C., E-mail: eauden@sandia.gov; Vizkelethy, G.; Serkland, D.K.; Bossert, D.J.; Doyle, B.L.

    2017-05-15

    The Hecht equation can be used to model the nonlinear degradation of charge collection efficiency (CCE) in response to radiation-induced displacement damage in both fully and partially depleted GaAs photodiodes. CCE degradation is measured for laser-generated photocurrent as a function of fluence and bias in Al{sub 0.3}Ga{sub 0.7}As/GaAs/Al{sub 0.25}Ga{sub 0.75}As p-i-n photodiodes which have been irradiated with 12 MeV C and 7.5 MeV Si ions. CCE is observed to degrade more rapidly with fluence in partially depleted photodiodes than in fully depleted photodiodes. When the intrinsic GaAs layer is fully depleted, the 2-carrier Hecht equation describes CCE degradation as photogenerated electrons and holes recombine at defect sites created by radiation damage in the depletion region. If the GaAs layer is partially depleted, CCE degradation is more appropriately modeled as the sum of the 2-carrier Hecht equation applied to electrons and holes generated within the depletion region and the 1-carrier Hecht equation applied to minority carriers that diffuse from the field-free (non-depleted) region into the depletion region. Enhanced CCE degradation is attributed to holes that recombine within the field-free region of the partially depleted intrinsic GaAs layer before they can diffuse into the depletion region.

  3. A position sensitive gamma-ray detector which employs photodiode and CsI (T1) crystals

    International Nuclear Information System (INIS)

    Dean, A.J.; Graham, G.; Hopkins, C.J.; Ramsden, D.; Lei, M.

    1987-01-01

    A compact CsI(Tl)/photodiode gamma-ray detector is described which is capable of locating the point of interaction of incident gamma-ray photons in the spectral region around 1 MeV. Laboratory tests are used to quantify both the spectral and positional resolutions of the detectors. Their likely application in space gamma-ray astronomy is also discussed

  4. Enhancing the far-UV sensitivity of silicon CMOS imaging arrays

    Science.gov (United States)

    Retherford, K. D.; Bai, Yibin; Ryu, Kevin K.; Gregory, J. A.; Welander, Paul B.; Davis, Michael W.; Greathouse, Thomas K.; Winter, Gregory S.; Suntharalingam, Vyshnavi; Beletic, James W.

    2014-07-01

    We report our progress toward optimizing backside-illuminated silicon PIN CMOS devices developed by Teledyne Imaging Sensors (TIS) for far-UV planetary science applications. This project was motivated by initial measurements at Southwest Research Institute (SwRI) of the far-UV responsivity of backside-illuminated silicon PIN photodiode test structures described in Bai et al., SPIE, 2008, which revealed a promising QE in the 100-200 nm range as reported in Davis et al., SPIE, 2012. Our effort to advance the capabilities of thinned silicon wafers capitalizes on recent innovations in molecular beam epitaxy (MBE) doping processes. Key achievements to date include: 1) Representative silicon test wafers were fabricated by TIS, and set up for MBE processing at MIT Lincoln Laboratory (LL); 2) Preliminary far-UV detector QE simulation runs were completed to aid MBE layer design; 3) Detector fabrication was completed through the pre-MBE step; and 4) Initial testing of the MBE doping process was performed on monitoring wafers, with detailed quality assessments. Early results suggest that potential challenges in optimizing the UV-sensitivity of silicon PIN type CMOS devices, compared with similar UV enhancement methods established for CCDs, have been mitigated through our newly developed methods. We will discuss the potential advantages of our approach and briefly describe future development steps.

  5. An Inexpensive and Simple Method to Demonstrate Soil Water and Nutrient Flow

    Science.gov (United States)

    Nichols, K. A.; Samson-Liebig, S.

    2011-01-01

    Soil quality, soil health, and soil sustainability are concepts that are being widely used but are difficult to define and illustrate, especially to a non-technical audience. The objectives of this manuscript were to develop simple and inexpensive methodologies to both qualitatively and quantitatively estimate water infiltration rates (IR),…

  6. Using a Raspberry Pi as a Versatile and Inexpensive Display Device

    Directory of Open Access Journals (Sweden)

    Edward Iglesias

    2013-07-01

    Full Text Available This article covers the process by which a library took some unused equipment and added a cheap computing device to produce very inexpensive but effective electronic signage. Hardware and software issues as well as a step-by-step guide through the process are included.

  7. An inexpensive and portable drill rig for bedrock groundwater studies in headwater catchments

    Science.gov (United States)

    C. Gabrielli; J.J. McDonnell

    2011-01-01

    Bedrock groundwater dynamics in headwater catchments are poorly understood and poorly characterized. Here, we present an inexpensive and portable bedrock drilling system designed for use in remote locations. Our system is capable of drilling bedrock wells up to 11 m deep and 38 mm in diameter in a wide range of bedrock types. The drill consists of a lawn mower engine...

  8. Short report: evaluation of a simple and inexpensive photometric device for the measurement of hemoglobin

    NARCIS (Netherlands)

    Borrmann, Steffen; Oyakhirome, Sunny; Esser, Gilbert; Trinkle, Cordula; Issifou, Saadou; Grobusch, Martin P.; Krishna, Sanjeev; Kremsner, Peter G.

    2004-01-01

    We have evaluated the accuracy of a simple and inexpensive photometric device (DHT) for the estimation of the blood concentration of hemoglobin by comparison with an automated, high-resolution, flow cytometry-based hematology analyzer (CellDyn 3000) and a centrifugal quantitative buffy coat

  9. Inexpensive camera systems for detecting martens, fishers, and other animals: guidelines for use and standardization.

    Science.gov (United States)

    Lawrence L.C. Jones; Martin G. Raphael

    1993-01-01

    Inexpensive camera systems have been successfully used to detect the occurrence of martens, fishers, and other wildlife species. The use of cameras is becoming widespread, and we give suggestions for standardizing techniques so that comparisons of data can occur across the geographic range of the target species. Details are given on equipment needs, setting up the...

  10. An Inexpensive Family Index of Risk for Mood Issues Improves Identification of Pediatric Bipolar Disorder

    Science.gov (United States)

    Algorta, Guillermo Perez; Youngstrom, Eric A.; Phelps, James; Jenkins, Melissa M.; Youngstrom, Jennifer Kogos; Findling, Robert L.

    2013-01-01

    Family history of mental illness provides important information when evaluating pediatric bipolar disorder (PBD). However, such information is often challenging to gather within clinical settings. This study investigates the feasibility and utility of gathering family history information using an inexpensive method practical for outpatient…

  11. Design and evaluation of an inexpensive radiation shield for monitoring surface air temperatures

    Science.gov (United States)

    Zachary A. Holden; Anna E. Klene; Robert F. Keefe; Gretchen G. Moisen

    2013-01-01

    Inexpensive temperature sensors are widely used in agricultural and forestry research. This paper describes a low-cost (~3 USD) radiation shield (radshield) designed for monitoring surface air temperatures in harsh outdoor environments. We compared the performance of the radshield paired with low-cost temperature sensors at three sites in western Montana to several...

  12. Could Rice Endosperm Be the Answer for Inexpensive HIV Protection? | Poster

    Science.gov (United States)

    According to a study in Plant Biotechnology Journal, genetically modified rice could be an inexpensive production platform for microbicides that inhibit HIV entry into target cells. Such a method could be one sustainable option for poverty-stricken countries with high rates of AIDS.

  13. Chiral silicon nanostructures

    International Nuclear Information System (INIS)

    Schubert, E.; Fahlteich, J.; Hoeche, Th.; Wagner, G.; Rauschenbach, B.

    2006-01-01

    Glancing angle ion beam assisted deposition is used for the growth of amorphous silicon nanospirals onto [0 0 1] silicon substrates in a temperature range from room temperature to 475 deg. C. The nanostructures are post-growth annealed in an argon atmosphere at various temperatures ranging from 400 deg. C to 800 deg. C. Recrystallization of silicon within the persisting nanospiral configuration is demonstrated for annealing temperatures above 800 deg. C. Transmission electron microscopy and Raman spectroscopy are used to characterize the silicon samples prior and after temperature treatment

  14. Silicon web process development

    Science.gov (United States)

    Duncan, C. S.; Seidensticker, R. G.; Mchugh, J. P.; Skutch, M. E.; Driggers, J. M.; Hopkins, R. H.

    1981-01-01

    The silicon web process takes advantage of natural crystallographic stabilizing forces to grow long, thin single crystal ribbons directly from liquid silicon. The ribbon, or web, is formed by the solidification of a liquid film supported by surface tension between two silicon filaments, called dendrites, which border the edges of the growing strip. The ribbon can be propagated indefinitely by replenishing the liquid silicon as it is transformed to crystal. The dendritic web process has several advantages for achieving low cost, high efficiency solar cells. These advantages are discussed.

  15. Spectrally dependent photovoltages in Schottky photodiode based on (100) B-doped diamond

    International Nuclear Information System (INIS)

    Čermák, Jan; Rezek, Bohuslav; Koide, Yasuo; Takeuchi, Daisuke

    2014-01-01

    Spectrally and spatially resolved photovoltages were measured by Kelvin probe force microscopy (KPFM) on a Schottky photo-diode made of a 4 nm thin tungsten-carbide (WC) layer on a 500 nm oxygen-terminated boron-doped diamond epitaxial layer (O-BDD) that was grown on a Ib (100) diamond substrate. The diode was grounded by the sideways ohmic contact (Ti/WC), and the semitransparent Schottky contact was let unconnected. The electrical potentials across the device were measured in dark (only 650 nm LED of KPFM being on), under broad-band white light (halogen lamp), UV (365 nm diode), and deep ultraviolet (deuterium lamp) illumination. Illumination induced shift of the electrical potential remains within 210 mV. We propose that the photovoltage actually corresponds to a shift of Fermi level inside the BDD channel and thereby explains orders of magnitude changes in photocurrent

  16. Spectrally dependent photovoltages in Schottky photodiode based on (100) B-doped diamond

    Science.gov (United States)

    Čermák, Jan; Koide, Yasuo; Takeuchi, Daisuke; Rezek, Bohuslav

    2014-02-01

    Spectrally and spatially resolved photovoltages were measured by Kelvin probe force microscopy (KPFM) on a Schottky photo-diode made of a 4 nm thin tungsten-carbide (WC) layer on a 500 nm oxygen-terminated boron-doped diamond epitaxial layer (O-BDD) that was grown on a Ib (100) diamond substrate. The diode was grounded by the sideways ohmic contact (Ti/WC), and the semitransparent Schottky contact was let unconnected. The electrical potentials across the device were measured in dark (only 650 nm LED of KPFM being on), under broad-band white light (halogen lamp), UV (365 nm diode), and deep ultraviolet (deuterium lamp) illumination. Illumination induced shift of the electrical potential remains within 210 mV. We propose that the photovoltage actually corresponds to a shift of Fermi level inside the BDD channel and thereby explains orders of magnitude changes in photocurrent.

  17. Low frequency noise in p-InAsSbP/n-InAs infrared photodiodes

    Science.gov (United States)

    Dyakonova, N.; Karandashev, S. A.; Levinshtein, M. E.; Matveev, B. A.; Remennyi, M. A.

    2018-06-01

    We report the first experimental study of low-frequency noise in p-InAsSbP/n-InAs infrared photodiodes. For forward bias, experiments have been carried out at 300 and 77 K, in the photovoltaic regime the measurements have been done at 300 K. At room temperature the current noise spectral density, SI , exhibits the ∼1/f frequency dependence. For low currents, I ≤ I 0 ∼ 4 × 10‑5 A, S I is proportional to I 2, at higher currents this dependence changes to S I ∼ I. At 77 K the noise spectral density is significantly higher than at 300 K, and Lorentzian contributions to noise are observed. The current dependences of spectral noise density can be approximately described as S I ∼ I 1.5 and show particularities suggesting the contribution of defects.

  18. Identification of radiation induced dark current sources in pinned photodiode CMOS image sensors

    International Nuclear Information System (INIS)

    Goiffon, V.; Virmontois, C.; Magnan, P.; Cervantes, P.; Place, S.; Estribeau, M.; Martin-Gonthier, P.; Gaillardin, M.; Girard, S.; Paillet, P.

    2012-01-01

    This paper presents an investigation of Total Ionizing Dose (TID) induced dark current sources in Pinned Photodiodes (PPD) CMOS Image Sensors based on pixel design variations. The influence of several layout parameters is studied. Only one parameter is changed at a time enabling the direct evaluation of its contribution to the observed device degradation. By this approach, the origin of radiation induced dark current in PPD is localized on the pixel layout. The PPD peripheral shallow trench isolation does not seem to play a role in the degradation. The PPD area and a transfer gate contribution independent of the pixel dimensions appear to be the main sources of the TID induced dark current increase. This study also demonstrates that applying a negative voltage on the transfer gate during integration strongly reduces the radiation induced dark current. (authors)

  19. Characterization of total ionizing dose damage in COTS pinned photodiode CMOS image sensors

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zujun, E-mail: wangzujun@nint.ac.cn; Ma, Wuying; Huang, Shaoyan; Yao, Zhibin; Liu, Minbo; He, Baoping; Sheng, Jiangkun; Xue, Yuan [State Key Laboratory of Intense Pulsed Radiation Simulation and Effect, Northwest Institute of Nuclear Technology, P.O.Box 69-10, Xi’an, Shaanxi 710024 (China); Liu, Jing [School of Materials Science and Engineering, Xiangtan University, Hunan (China)

    2016-03-15

    The characterization of total ionizing dose (TID) damage in COTS pinned photodiode (PPD) CMOS image sensors (CISs) is investigated. The radiation experiments are carried out at a {sup 60}Co γ-ray source. The CISs are produced by 0.18-μm CMOS technology and the pixel architecture is 8T global shutter pixel with correlated double sampling (CDS) based on a 4T PPD front end. The parameters of CISs such as temporal domain, spatial domain, and spectral domain are measured at the CIS test system as the EMVA 1288 standard before and after irradiation. The dark current, random noise, dark signal non-uniformity (DSNU), photo response non-uniformity (PRNU), overall system gain, saturation output, dynamic range (DR), signal to noise ratio (SNR), quantum efficiency (QE), and responsivity versus the TID are reported. The behaviors of the tested CISs show remarkable degradations after radiation. The degradation mechanisms of CISs induced by TID damage are also analyzed.

  20. Design and implementation of a prototype for metrology with UVED and photodiodes

    International Nuclear Information System (INIS)

    Hidalgo Padilla, Rodney Ernesto

    2013-01-01

    A test system was developed for measuring radiant flux produced by a UVED, using photodiodes with the aim of improving metrology systems used in LAFTLA (Laboratorio de Fotonica y Tecnologia Laser, Universidad de Costa Rica). The system has been used to calibrate three teams of measurement. The calibration procedure has been to measure the radiation of UVED using the devices. Each device has repeated the measurement process, with a pattern, comparing the values obtained and taking into account the differences between areas of the sensors. Problems with the maximum capacity of measuring equipment were solved, in some cases this capacity was less than the required. Some sources of error have been identified, for example, the differences between the theoretical and actual values of the specifications. (author) [es

  1. Measurement of impurity emission profiles in CHS Plasma using AXUV photodiode arrays and VUV bandpass filters

    International Nuclear Information System (INIS)

    Suzuki, C.; Peterson, B.J.; Ida, K.

    2004-01-01

    We have designed a compact and low-cost diagnostic system for spatiotemporal distributions of specific vacuum ultraviolet (VUV) emission lines from impurities in Compact Helical System (CHS) plasmas. The system consists of 20 channel absolute extreme ultraviolet photodiode arrays combined with interchangeable thin foil filters which have passbands in the VUV region. A compact mounting module which contains all the components including an in-vacuum preamplifier for immediate current-voltage conversion has been designed and successfully fabricated. A preliminary measurement with a single module using an aluminum foil filter has been carried out for monitoring the behavior of oxygen impurity in CHS, and initial results have been obtained. Two identical modules equipped with Versa Module European bus-based analog-digital converters will be available for future tomographic measurements

  2. Impulse response measurement in the HgCdTe avalanche photodiode

    Science.gov (United States)

    Singh, Anand; Pal, Ravinder

    2018-04-01

    HgCdTe based mid-wave infrared focal plane arrays (MWIR FPAs) are being developed for high resolution imaging and range determination of distant camouflaged targets. Effect of bandgap grading on the response time in the n+/ν/p+ HgCdTe electron avalanche photodiode (e-APD) is evaluated using impulse response measurement. Gain normalized dark current density of 2 × 10-9 A/cm2 at low reverse bias for passive mode and 2 × 10-4 A/cm2 at -8 V for active mode is measured in the fabricated APD device, yielding high gain bandwidth product of 2.4 THZ at the maximum gain. Diffusion of carriers is minimized to achieve transit time limited impulse response by introducing composition grading in the HgCdTe epilayer. The noise equivalent photon performance less than one is achievable in the FPA that is suitable for active cum passive imaging applications.

  3. Linear Mode HgCdTe Avalanche Photodiodes for Photon Counting Applications

    Science.gov (United States)

    Sullivan, William, III; Beck, Jeffrey; Scritchfield, Richard; Skokan, Mark; Mitra, Pradip; Sun, Xiaoli; Abshire, James; Carpenter, Darren; Lane, Barry

    2015-01-01

    An overview of recent improvements in the understanding and maturity of linear mode photon counting with HgCdTe electron-initiated avalanche photodiodes is presented. The first HgCdTe LMPC 2x8 format array fabricated in 2011 with 64 micron pitch was a remarkable success in terms of demonstrating a high single photon signal to noise ratio of 13.7 with an excess noise factor of 1.3-1.4, a 7 ns minimum time between events, and a broad spectral response extending from 0.4 micron to 4.2 micron. The main limitations were a greater than 10x higher false event rate than expected of greater than 1 MHz, a 5-7x lower than expected APD gain, and a photon detection efficiency of only 50% when greater than 60% was expected. This paper discusses the reasons behind these limitations and the implementation of their mitigations with new results.

  4. Post-processing Free Quantum Random Number Generator Based on Avalanche Photodiode Array

    International Nuclear Information System (INIS)

    Li Yang; Liao Sheng-Kai; Liang Fu-Tian; Shen Qi; Liang Hao; Peng Cheng-Zhi

    2016-01-01

    Quantum random number generators adopting single photon detection have been restricted due to the non-negligible dead time of avalanche photodiodes (APDs). We propose a new approach based on an APD array to improve the generation rate of random numbers significantly. This method compares the detectors' responses to consecutive optical pulses and generates the random sequence. We implement a demonstration experiment to show its simplicity, compactness and scalability. The generated numbers are proved to be unbiased, post-processing free, ready to use, and their randomness is verified by using the national institute of standard technology statistical test suite. The random bit generation efficiency is as high as 32.8% and the potential generation rate adopting the 32 × 32 APD array is up to tens of Gbits/s. (paper)

  5. Alpha particles spectrometer with photodiode PIN; Espectrometro de particulas alfa con fotodiodo PIN

    Energy Technology Data Exchange (ETDEWEB)

    Chacon R, A.; Hernandez V, R.; Hernandez D, V. M.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidades Academicas de Estudios Nucleares e Ingenieria Electrica, Calle Cipres No. 10, Fracc. La Penuela, 09869 Zacatecas (Mexico); Ramirez G, J. [Instituto Nacional de Estadistica Geografia e Informatica, Direccion General de Innovacion y Tecnologia de Informacion, Av. Heroes de Nacozari Sur 2301, Fracc. Jardines del Parque, 20276 Aguascalientes (Mexico)], e-mail: achruiz@hotmail.com

    2009-10-15

    The radiation propagates in form of electromagnetic waves or corpuscular radiation; if the radiation energy causes ionization in environment that crosses it is considered ionizing radiation. To detect radiation several detectors types are used, if the radiation are alpha particles are used detectors proportional type or trace elements. In this work the design results, construction and tests of an alpha particles spectrometer are presented, which was designed starting from a photodiode PIN type. The system design was simulated with a code for electronic circuits. With results of simulation phase was constructed the electronic phase that is coupled to a multichannel analyzer. The resulting electronic is evaluated analyzing the electronic circuit performance before an alphas triple source and alpha radiation that produce two smoke detectors of domestic use. On the tests phase we find that the system allows obtain, in a multichannel, the pulses height spectrum, with which we calibrate the system. (Author)

  6. X-ray fluorescence hologram data collection with a cooled avalanche photodiode

    CERN Document Server

    Hayashi, K; Matsubara, E I; Kishimoto, S; Mori, T; Tanaka, M

    2002-01-01

    A high counting rate X-ray detector with an appropriate energy resolution is desired for high quality X-ray fluorescence hologram measurements because a holographic pattern is detected as extremely small intensity variations of X-ray fluorescence on a large intensity background. A cooled avalanche photodiode (APD), which has about 10% energy resolution and is designed for a high counting rate, fits the above requirements. Reconstructed atomic images from experimental holograms using the APD system provide us a clear view of the first and second neighbor atoms around an emitter. The present result proved that a combination of this APD system and a synchrotron X-ray source enables us to measure a high quality hologram for a reasonable measurement time.

  7. Burr formation detector for fiber laser cutting based on a photodiode sensor system

    Science.gov (United States)

    Schleier, Max; Adelmann, Benedikt; Neumeier, Benedikt; Hellmann, Ralf

    2017-11-01

    We report a unique sensor system based on a InGaAs photodiode to detect the formation of burr during near infrared fiber laser cutting. The sensor approach encompasses the measurement of the thermal radiation form the process zone, optical filtering, digitalized sampling at 20 kHz, digital filtering using an elliptical band-pass filter 12th order and calculation of the standard deviation. We find a linear correlation between the deduced sensor signal and the generated burr height with this functionality being experimentally confirmed for laser cutting of mild and stainless steel of different thicknesses. The underlying mechanism of this transducer concept is attributed to the melt flow dynamics inside the cut kerf.

  8. Problems and solutions in high-rate multichannel hybrid photodiode design The CMS experience

    CERN Document Server

    Cushman, P B

    2002-01-01

    The unique conditions of the CMS experiment (4 T magnetic field, restricted access, high neutron radiation, and 25-ns bunch-crossings) necessitated the development of a new type of high-rate multichannel hybrid photodiode for the tile/fiber hadronic calorimeter. New complexities arose in the push toward high-rate operation, necessitating design changes in the diode structure and surface treatment. The product is now capable of high-rate operation with low crosstalk and leakage current. Lifetime studies of high-voltage behavior, total charge, and irradiation have shown that the tubes will survive the ten years of CMS running with only a few percent change in gain and manageable leakage current rise. (13 refs).

  9. Ultralow noise midwave infrared InAs-GaSb strain layer superlattice avalanche photodiode

    International Nuclear Information System (INIS)

    Mallick, Shubhrangshu; Banerjee, Koushik; Ghosh, Siddhartha; Plis, Elena; Rodriguez, Jean Baptiste; Krishna, Sanjay; Grein, Christoph

    2007-01-01

    Eye-safe midwavelength infrared InAs-GaSb strain layer superlattice p + -n - -n homojunction avalanche photodiodes (APDs) grown by solid source molecular beam epitaxy were fabricated and characterized. Maximum multiplication gain of 1800 was measured at -20 V at 77 K. Excess noise factors between 0.8 and 1.2 were measured up to gain of 300. Gain of 200 was measured at 120 K. Exponential nature of the gain as a function of reverse bias along with low excess noise factor at higher gain confirms single carrier electron-only impact ionization in the avalanche regime. Decrease in the multiplication gain at higher temperatures correlates with standard APD characteristics

  10. Spectrally dependent photovoltages in Schottky photodiode based on (100) B-doped diamond

    Energy Technology Data Exchange (ETDEWEB)

    Čermák, Jan, E-mail: cermakj@fzu.cz; Rezek, Bohuslav [Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10, 16200 Prague 6 (Czech Republic); Koide, Yasuo [Sensor Materials Center, National Institute for Material Science (NIMS), 1-1 Namiki, Tsukuba 305-0044 (Japan); Takeuchi, Daisuke [Energy Technology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba 305-8568 (Japan)

    2014-02-07

    Spectrally and spatially resolved photovoltages were measured by Kelvin probe force microscopy (KPFM) on a Schottky photo-diode made of a 4 nm thin tungsten-carbide (WC) layer on a 500 nm oxygen-terminated boron-doped diamond epitaxial layer (O-BDD) that was grown on a Ib (100) diamond substrate. The diode was grounded by the sideways ohmic contact (Ti/WC), and the semitransparent Schottky contact was let unconnected. The electrical potentials across the device were measured in dark (only 650 nm LED of KPFM being on), under broad-band white light (halogen lamp), UV (365 nm diode), and deep ultraviolet (deuterium lamp) illumination. Illumination induced shift of the electrical potential remains within 210 mV. We propose that the photovoltage actually corresponds to a shift of Fermi level inside the BDD channel and thereby explains orders of magnitude changes in photocurrent.

  11. Measurement-based characterization of multipixel avalanche photodiodes for scintillating detectors

    CERN Document Server

    Dziewiecki, M

    2012-01-01

    Multipixel avalanche photodiodes (MAPD) are recently gaining popularity in high energy physics experiments as an attractive replacement for photomultiplier tubes, which have been extensively used for many years as a part of various scintillating detectors. Their low price, small dimensions and another features facilitating their use (like mechanical shock resistance, magnetic field immunity or moderate supply voltage) make the MAPDs a good choice for commercial use as well, what is reflected in growing number of producers as well as MAPD models available on the market. This dissertation presents Author’s experience with MAPD measurements and modelling, gained during his work on the T2K (Tokai-to-Kamioka) long-baseline neutrino experiment, carried out by an international collaboration in Japan. First, operation principle of the MAPD, definitions of various parameters and measurement methods are discussed. Then, a device for large-scale MAPD measurements and related data processing methods are described. Fina...

  12. Switching characteristic and capacitance analysis of a-Si:H pinpin photodiodes for visible range telecommunications

    Science.gov (United States)

    Fantoni, A.; Fernandes, M.; Louro, P.; Vieira, M.

    2016-05-01

    The device under study is an a-SiC:H/a-Si:H pinpin photodiodes produced by PECVD (Plasma Enhanced Chemical Vapour Deposition) and has a structure that consists of a p-i'(a-SiC:H)-n/p-i(a-Si:H)-n heterostructure with low conductivity doped layers. This device structure has been demonstrated useful in optical communications that use the WDM technique to encode multiple signals in the visible light range. We present in this work experimental results about C-V measurements of the device under complex conditions of illumination. Also it is presented an analysis based on the transient response of the device when illuminated by a pulsed light, with and without optical bias superposition. Rising and decaying times of the collected photocurrent will be outlined under the different conditions. A simulation study outlines the role played by each pin substructure on the response speed and gives some hint on the possible optimization of this device.

  13. p-Cu2O-shell/n-TiO2-nanowire-core heterostucture photodiodes

    Directory of Open Access Journals (Sweden)

    Hsueh Ting-Jen

    2011-01-01

    Full Text Available Abstract This study reports the deposition of cuprous oxide [Cu2O] onto titanium dioxide [TiO2] nanowires [NWs] prepared on TiO2/glass templates. The average length and average diameter of these thermally oxidized and evaporated TiO2 NWs are 0.1 to 0.4 μm and 30 to 100 nm, respectively. The deposited Cu2O fills gaps between the TiO2 NWs with good step coverage to form nanoshells surrounding the TiO2 cores. The p-Cu2O/n-TiO2 NW heterostructure exhibits a rectifying behavior with a sharp turn-on at approximately 0.9 V. Furthermore, the fabricated p-Cu2O-shell/n-TiO2-nanowire-core photodiodes exhibit reasonably large photocurrent-to-dark-current contrast ratios and fast responses.

  14. Composite metal oxide semiconductor based photodiodes for solar panel tracking applications

    Energy Technology Data Exchange (ETDEWEB)

    Al-Ghamdi, Ahmed A., E-mail: aghamdi90@hotmail.com [Department of Physics, Faculty of Science, King Abdulaziz University, Jeddah (Saudi Arabia); Dere, A. [Department of Physics, Faculty of Science, Firat University, Elazig (Turkey); Tataroğlu, A. [Department of Physics, Faculty of Science, Gazi University, Ankara (Turkey); Arif, Bilal [Department of Physics, Faculty of Science, Firat University, Elazig (Turkey); Yakuphanoglu, F. [Department of Physics, Faculty of Science, King Abdulaziz University, Jeddah (Saudi Arabia); Department of Physics, Faculty of Science, Firat University, Elazig (Turkey); El-Tantawy, Farid [Department of Physics, Faculty of Science, Suez Canal University, Ismailia (Egypt); Farooq, W.A. [Physics and Astronomy Department, College of Science, King Saud University, Riyadh (Saudi Arabia)

    2015-11-25

    The Zn{sub 1−x}Al{sub x}O:Cu{sub 2}O composite films were synthesized by the sol gel method to fabricate photodiodes. The transparent metal oxide Zn{sub 1−x}Al{sub x}O:Cu{sub 2}O thin films were grown on p-Si substrates by spin coating technique. Electrical characterization of the p-Si/AZO:Cu{sub 2}O photodiodes was performed by current–voltage and capacitance–conductance–voltage characteristics under dark and various illumination conditions. The transient photocurrent of the diodes increases with increase in illumination intensity. The photoconducting mechanism of the diodes is controlled by the continuous distribution of trap levels. The photocapacitance and photoconductivity of the diodes are decreased with increasing Cu{sub 2}O content. The series resistance–voltage behavior confirms the presence of the interface states in the interface of the diodes. The photoresponse properties of the diodes indicate that the p-Si/Zn{sub 1−x}Al{sub x}O–Cu{sub 2}O diodes can be used as a photosensor in solar panel tracking applications. - Highlights: • Zn{sub 1−x}Al{sub x}O:Cu{sub 2}O composite films were synthesized by the sol gel method. • p-Si/Zn{sub 1−x}Al{sub x}O–Cu{sub 2}O diodes were fabricated. • p-Si/Zn{sub 1−x}Al{sub x}O–Cu{sub 2}O diodes can be used in the optoelectronic applications.

  15. Periodically poled silicon

    Science.gov (United States)

    Hon, Nick K.; Tsia, Kevin K.; Solli, Daniel R.; Khurgin, Jacob B.; Jalali, Bahram

    2010-02-01

    Bulk centrosymmetric silicon lacks second-order optical nonlinearity χ(2) - a foundational component of nonlinear optics. Here, we propose a new class of photonic device which enables χ(2) as well as quasi-phase matching based on periodic stress fields in silicon - periodically-poled silicon (PePSi). This concept adds the periodic poling capability to silicon photonics, and allows the excellent crystal quality and advanced manufacturing capabilities of silicon to be harnessed for devices based on χ(2)) effects. The concept can also be simply achieved by having periodic arrangement of stressed thin films along a silicon waveguide. As an example of the utility, we present simulations showing that mid-wave infrared radiation can be efficiently generated through difference frequency generation from near-infrared with a conversion efficiency of 50% based on χ(2) values measurements for strained silicon reported in the literature [Jacobson et al. Nature 441, 199 (2006)]. The use of PePSi for frequency conversion can also be extended to terahertz generation. With integrated piezoelectric material, dynamically control of χ(2)nonlinearity in PePSi waveguide may also be achieved. The successful realization of PePSi based devices depends on the strength of the stress induced χ(2) in silicon. Presently, there exists a significant discrepancy in the literature between the theoretical and experimentally measured values. We present a simple theoretical model that produces result consistent with prior theoretical works and use this model to identify possible reasons for this discrepancy.

  16. Nonlinear silicon photonics

    Science.gov (United States)

    Tsia, Kevin K.; Jalali, Bahram

    2010-05-01

    An intriguing optical property of silicon is that it exhibits a large third-order optical nonlinearity, with orders-ofmagnitude larger than that of silica glass in the telecommunication band. This allows efficient nonlinear optical interaction at relatively low power levels in a small footprint. Indeed, we have witnessed a stunning progress in harnessing the Raman and Kerr effects in silicon as the mechanisms for enabling chip-scale optical amplification, lasing, and wavelength conversion - functions that until recently were perceived to be beyond the reach of silicon. With all the continuous efforts developing novel techniques, nonlinear silicon photonics is expected to be able to reach even beyond the prior achievements. Instead of providing a comprehensive overview of this field, this manuscript highlights a number of new branches of nonlinear silicon photonics, which have not been fully recognized in the past. In particular, they are two-photon photovoltaic effect, mid-wave infrared (MWIR) silicon photonics, broadband Raman effects, inverse Raman scattering, and periodically-poled silicon (PePSi). These novel effects and techniques could create a new paradigm for silicon photonics and extend its utility beyond the traditionally anticipated applications.

  17. Nonlinear silicon photonics

    Science.gov (United States)

    Borghi, M.; Castellan, C.; Signorini, S.; Trenti, A.; Pavesi, L.

    2017-09-01

    Silicon photonics is a technology based on fabricating integrated optical circuits by using the same paradigms as the dominant electronics industry. After twenty years of fervid development, silicon photonics is entering the market with low cost, high performance and mass-manufacturable optical devices. Until now, most silicon photonic devices have been based on linear optical effects, despite the many phenomenologies associated with nonlinear optics in both bulk materials and integrated waveguides. Silicon and silicon-based materials have strong optical nonlinearities which are enhanced in integrated devices by the small cross-section of the high-index contrast silicon waveguides or photonic crystals. Here the photons are made to strongly interact with the medium where they propagate. This is the central argument of nonlinear silicon photonics. It is the aim of this review to describe the state-of-the-art in the field. Starting from the basic nonlinearities in a silicon waveguide or in optical resonator geometries, many phenomena and applications are described—including frequency generation, frequency conversion, frequency-comb generation, supercontinuum generation, soliton formation, temporal imaging and time lensing, Raman lasing, and comb spectroscopy. Emerging quantum photonics applications, such as entangled photon sources, heralded single-photon sources and integrated quantum photonic circuits are also addressed at the end of this review.

  18. Silicon germanium mask for deep silicon etching

    KAUST Repository

    Serry, Mohamed

    2014-07-29

    Polycrystalline silicon germanium (SiGe) can offer excellent etch selectivity to silicon during cryogenic deep reactive ion etching in an SF.sub.6/O.sub.2 plasma. Etch selectivity of over 800:1 (Si:SiGe) may be achieved at etch temperatures from -80 degrees Celsius to -140 degrees Celsius. High aspect ratio structures with high resolution may be patterned into Si substrates using SiGe as a hard mask layer for construction of microelectromechanical systems (MEMS) devices and semiconductor devices.

  19. Silicon germanium mask for deep silicon etching

    KAUST Repository

    Serry, Mohamed; Rubin, Andrew; Refaat, Mohamed; Sedky, Sherif; Abdo, Mohammad

    2014-01-01

    Polycrystalline silicon germanium (SiGe) can offer excellent etch selectivity to silicon during cryogenic deep reactive ion etching in an SF.sub.6/O.sub.2 plasma. Etch selectivity of over 800:1 (Si:SiGe) may be achieved at etch temperatures from -80 degrees Celsius to -140 degrees Celsius. High aspect ratio structures with high resolution may be patterned into Si substrates using SiGe as a hard mask layer for construction of microelectromechanical systems (MEMS) devices and semiconductor devices.

  20. Optimization of the digital Silicon Photomultiplier for Cherenkov light detection

    International Nuclear Information System (INIS)

    Frach, T

    2012-01-01

    The Silicon Photomultiplier is a promising alternative to fast vacuum photodetectors. We developed a fully digital implementation of the Silicon Photomultiplier. The sensor is based on a single photon avalanche photodiode (SPAD) integrated in a standard CMOS process. Photons are detected directly by sensing the voltage at the SPAD anode using a dedicated cell electronics block next to each diode. This block also contains active quenching and recharge circuits as well as a one bit memory for the selective inhibit of detector cells. A balanced trigger network is used to propagate the trigger signal from all cells to the integrated time-to-digital converter. Photons are detected and counted as digital signals, thus making the sensor less susceptible to temperature variations and electronic noise. The integration with CMOS logic has the added benefit of low power consumption and possible integration of data post-processing in the sensor. In this paper, we discuss the sensor architecture together with its characteristics, and its possible optimizations for applications requiring the detection of Cherenkov light.

  1. Simple and inexpensive microfluidic devices for the generation of monodisperse multiple emulsions

    KAUST Repository

    Li, Erqiang

    2013-12-16

    Droplet-based microfluidic devices have become a preferred versatile platform for various fields in physics, chemistry and biology. Polydimethylsiloxane soft lithography, the mainstay for fabricating microfluidic devices, usually requires the usage of expensive apparatus and a complex manufacturing procedure. Here, we report the design and fabrication of simple and inexpensive microfluidic devices based on microscope glass slides and pulled glass capillaries, for generating monodisperse multiple emulsions. The advantages of our method lie in a simple manufacturing procedure, inexpensive processing equipment and flexibility in the surface modification of the designed microfluidic devices. Different types of devices have been designed and tested and the experimental results demonstrated their robustness for preparing monodisperse single, double, triple and multi-component emulsions. © 2014 IOP Publishing Ltd.

  2. Process for making silicon

    Science.gov (United States)

    Levin, Harry (Inventor)

    1987-01-01

    A reactor apparatus (10) adapted for continuously producing molten, solar grade purity elemental silicon by thermal reaction of a suitable precursor gas, such as silane (SiH.sub.4), is disclosed. The reactor apparatus (10) includes an elongated reactor body (32) having graphite or carbon walls which are heated to a temperature exceeding the melting temperature of silicon. The precursor gas enters the reactor body (32) through an efficiently cooled inlet tube assembly (22) and a relatively thin carbon or graphite septum (44). The septum (44), being in contact on one side with the cooled inlet (22) and the heated interior of the reactor (32) on the other side, provides a sharp temperature gradient for the precursor gas entering the reactor (32) and renders the operation of the inlet tube assembly (22) substantially free of clogging. The precursor gas flows in the reactor (32) in a substantially smooth, substantially axial manner. Liquid silicon formed in the initial stages of the thermal reaction reacts with the graphite or carbon walls to provide a silicon carbide coating on the walls. The silicon carbide coated reactor is highly adapted for prolonged use for production of highly pure solar grade silicon. Liquid silicon (20) produced in the reactor apparatus (10) may be used directly in a Czochralski or other crystal shaping equipment.

  3. Hydrogen in amorphous silicon

    International Nuclear Information System (INIS)

    Peercy, P.S.

    1980-01-01

    The structural aspects of amorphous silicon and the role of hydrogen in this structure are reviewed with emphasis on ion implantation studies. In amorphous silicon produced by Si ion implantation of crystalline silicon, the material reconstructs into a metastable amorphous structure which has optical and electrical properties qualitatively similar to the corresponding properties in high-purity evaporated amorphous silicon. Hydrogen studies further indicate that these structures will accomodate less than or equal to 5 at.% hydrogen and this hydrogen is bonded predominantly in a monohydride (SiH 1 ) site. Larger hydrogen concentrations than this can be achieved under certain conditions, but the excess hydrogen may be attributed to defects and voids in the material. Similarly, glow discharge or sputter deposited amorphous silicon has more desirable electrical and optical properties when the material is prepared with low hydrogen concentration and monohydride bonding. Results of structural studies and hydrogen incorporation in amorphous silicon were discussed relative to the different models proposed for amorphous silicon

  4. Transformational silicon electronics

    KAUST Repository

    Rojas, Jhonathan Prieto

    2014-02-25

    In today\\'s traditional electronics such as in computers or in mobile phones, billions of high-performance, ultra-low-power devices are neatly integrated in extremely compact areas on rigid and brittle but low-cost bulk monocrystalline silicon (100) wafers. Ninety percent of global electronics are made up of silicon. Therefore, we have developed a generic low-cost regenerative batch fabrication process to transform such wafers full of devices into thin (5 μm), mechanically flexible, optically semitransparent silicon fabric with devices, then recycling the remaining wafer to generate multiple silicon fabric with chips and devices, ensuring low-cost and optimal utilization of the whole substrate. We show monocrystalline, amorphous, and polycrystalline silicon and silicon dioxide fabric, all from low-cost bulk silicon (100) wafers with the semiconductor industry\\'s most advanced high-κ/metal gate stack based high-performance, ultra-low-power capacitors, field effect transistors, energy harvesters, and storage to emphasize the effectiveness and versatility of this process to transform traditional electronics into flexible and semitransparent ones for multipurpose applications. © 2014 American Chemical Society.

  5. Viability study of photodiodes utilization in determination of soil water content by gamma transmission

    International Nuclear Information System (INIS)

    Santos, L.A.P.; Khoury, H.; Carneiro, C.J.G.

    1991-01-01

    An experiment to verify the viability of using silicon photodetectors in a sup(241)Am γ-ray spectroscopy system for measuring soil water content was carried out in disturbed soil cores. The good correlation between the logarithm of the attenuation factor and the water content, r sup(2)=0.99, proves that the low efficiency of these detectors is not a limiting factor in measuring the water content. Furthermore, the small dimensions of the silicon photodetectors and associate electronic equipment are important characteristics that could permit the construction of a portable gammametry system to be used under field conditions. (author)

  6. High performance CaS solar-blind ultraviolet photodiodes fabricated by seed-layer-assisted growth

    International Nuclear Information System (INIS)

    He, Qing Lin; Lai, Ying Hoi; Sou, Iam Keong; Liu, Yi; Beltjens, Emeline; Qi, Jie

    2015-01-01

    CaS, with a direct bandgap of 5.38 eV, is expected to be a strong candidate as the active-layer of high performance solar-blind UV photodiodes that have important applications in both civilian and military sectors. Here, we report that a seed-layer-assisted growth approach via molecular beam epitaxy can result in high crystalline quality rocksalt CaS thin films on zincblende GaAs substrates. The Au/CaS/GaAs solar-blind photodiodes demonstrated , more than five orders in its visible rejection power, a photoresponse of 36.8 mA/w at zero bias and a corresponding quantum efficiency as high as 19% at 235 nm

  7. Large-area, low-noise, high-speed, photodiode-based fluorescence detectors with fast overdrive recovery

    International Nuclear Information System (INIS)

    Bickman, S.; DeMille, D.

    2005-01-01

    Two large-area, low-noise, high-speed fluorescence detectors have been built. One detector consists of a photodiode with an area of 28 mmx28 mm and a low-noise transimpedance amplifier. This detector has a input light-equivalent spectral noise density of less than 3 pW/√(Hz), can recover from a large scattered light pulse within 10 μs, and has a bandwidth of at least 900 kHz. The second detector consists of a 16-mm-diam avalanche photodiode and a low-noise transimpedance amplifier. This detector has an input light-equivalent spectral noise density of 0.08 pW/√(Hz), also can recover from a large scattered light pulse within 10 μs, and has a bandwidth of 1 MHz

  8. On the front and back side quantum efficiency differences in semi-transparent organic solar cells and photodiodes

    Science.gov (United States)

    Bouthinon, B.; Clerc, R.; Verilhac, J. M.; Racine, B.; De Girolamo, J.; Jacob, S.; Lienhard, P.; Joimel, J.; Dhez, O.; Revaux, A.

    2018-03-01

    The External Quantum Efficiency (EQE) of semi-transparent Bulk Hetero-Junction (BHJ) organic photodiodes processed in air shows significant differences when measured from the front or back side contacts. This difference was found significantly reduced when decreasing the active layer thickness or by applying a negative bias. This work brings new elements to help understanding this effect, providing a large set of experiments featuring different applied voltages, active layers, process conditions, and electron and hole layers. By means of detailed electrical simulations, all these measurements have been found consistent with the mechanisms of irreversible photo-oxidation, modeled as deep trap states (and not as p-type doping). The EQE measurement from front and back sides is thus a simple and efficient way of monitoring the presence and amplitude of oxygen contamination in BHJ organic solar cells and photodiodes.

  9. Silicon micromachined vibrating gyroscopes

    Science.gov (United States)

    Voss, Ralf

    1997-09-01

    This work gives an overview of silicon micromachined vibrating gyroscopes. Market perspectives and fields of application are pointed out. The advantage of using silicon micromachining is discussed and estimations of the desired performance, especially for automobiles are given. The general principle of vibrating gyroscopes is explained. Vibrating silicon gyroscopes can be divided into seven classes. for each class the characteristic principle is presented and examples are given. Finally a specific sensor, based on a tuning fork for automotive applications with a sensitivity of 250(mu) V/degrees is described in detail.

  10. Porous silicon gettering

    Energy Technology Data Exchange (ETDEWEB)

    Tsuo, Y.S.; Menna, P.; Pitts, J.R. [National Renewable Energy Lab., Golden, CO (United States)] [and others

    1996-05-01

    The authors have studied a novel extrinsic gettering method that uses the large surface areas produced by a porous-silicon etch as gettering sites. The annealing step of the gettering used a high-flux solar furnace. They found that a high density of photons during annealing enhanced the impurity diffusion to the gettering sites. The authors used metallurgical-grade Si (MG-Si) prepared by directional solidification casing as the starting material. They propose to use porous-silicon-gettered MG-Si as a low-cost epitaxial substrate for polycrystalline silicon thin-film growth.

  11. Silicon etch process

    International Nuclear Information System (INIS)

    Day, D.J.; White, J.C.

    1984-01-01

    A silicon etch process wherein an area of silicon crystal surface is passivated by radiation damage and non-planar structure produced by subsequent anisotropic etching. The surface may be passivated by exposure to an energetic particle flux - for example an ion beam from an arsenic, boron, phosphorus, silicon or hydrogen source, or an electron beam. Radiation damage may be used for pattern definition and/or as an etch stop. Ethylenediamine pyrocatechol or aqueous potassium hydroxide anisotropic etchants may be used. The radiation damage may be removed after etching by thermal annealing. (author)

  12. Silicon integrated circuit process

    International Nuclear Information System (INIS)

    Lee, Jong Duck

    1985-12-01

    This book introduces the process of silicon integrated circuit. It is composed of seven parts, which are oxidation process, diffusion process, ion implantation process such as ion implantation equipment, damage, annealing and influence on manufacture of integrated circuit and device, chemical vapor deposition process like silicon Epitaxy LPCVD and PECVD, photolithography process, including a sensitizer, spin, harden bake, reflection of light and problems related process, infrared light bake, wet-etch, dry etch, special etch and problems of etching, metal process like metal process like metal-silicon connection, aluminum process, credibility of aluminum and test process.

  13. Silicon integrated circuit process

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong Duck

    1985-12-15

    This book introduces the process of silicon integrated circuit. It is composed of seven parts, which are oxidation process, diffusion process, ion implantation process such as ion implantation equipment, damage, annealing and influence on manufacture of integrated circuit and device, chemical vapor deposition process like silicon Epitaxy LPCVD and PECVD, photolithography process, including a sensitizer, spin, harden bake, reflection of light and problems related process, infrared light bake, wet-etch, dry etch, special etch and problems of etching, metal process like metal process like metal-silicon connection, aluminum process, credibility of aluminum and test process.

  14. Silicon nanowire hybrid photovoltaics

    KAUST Repository

    Garnett, Erik C.; Peters, Craig; Brongersma, Mark; Cui, Yi; McGehee, Mike

    2010-01-01

    Silicon nanowire Schottky junction solar cells have been fabricated using n-type silicon nanowire arrays and a spin-coated conductive polymer (PEDOT). The polymer Schottky junction cells show superior surface passivation and open-circuit voltages compared to standard diffused junction cells with native oxide surfaces. External quantum efficiencies up to 88% were measured for these silicon nanowire/PEDOT solar cells further demonstrating excellent surface passivation. This process avoids high temperature processes which allows for low-cost substrates to be used. © 2010 IEEE.

  15. Silicon nanowire hybrid photovoltaics

    KAUST Repository

    Garnett, Erik C.

    2010-06-01

    Silicon nanowire Schottky junction solar cells have been fabricated using n-type silicon nanowire arrays and a spin-coated conductive polymer (PEDOT). The polymer Schottky junction cells show superior surface passivation and open-circuit voltages compared to standard diffused junction cells with native oxide surfaces. External quantum efficiencies up to 88% were measured for these silicon nanowire/PEDOT solar cells further demonstrating excellent surface passivation. This process avoids high temperature processes which allows for low-cost substrates to be used. © 2010 IEEE.

  16. Room-temperature broadband InAsSb flip-chip photodiodes with λcutoff = 4.5 μm

    International Nuclear Information System (INIS)

    Zakhgeim, A. L.; Zotova, N. V.; Il'inskaya, N. D.; Karandashev, S. A.; Matveev, B. A.; Remennyi, M. A.; Stus', N. M.; Chernyakov, A. E.

    2009-01-01

    Equilibrium and nonequilibrium IR images of p-InAsSbP/n-InAsSb/n + -InAs photodiodes including the images obtained in the electroluminescence and negative luminescence modes have been analyzed. The contact reflectivity has been evaluated. The influence of the substrate's doping level and mesa depth on the quantum efficiency and sensitivity of a backside illuminated photodiode sensitive in the 2.7-4.5 μm range is discussed.

  17. Room-temperature broadband InAsSb flip-chip photodiodes with {lambda}{sub cutoff} = 4.5 {mu}m

    Energy Technology Data Exchange (ETDEWEB)

    Zakhgeim, A L [Russian Academy of Sciences, Scientific-Technological Center for Microelectronics and Submicron Heterostructures at Ioffe Physicotechnical Institute (Russian Federation); Zotova, N V; Il' inskaya, N D; Karandashev, S A; Matveev, B. A., E-mail: bmat@iropt3.ioffe.rssi.ru; Remennyi, M A; Stus' , N M [Russian Academy of Sciences, Ioffe Physicotechnical Institute (Russian Federation); Chernyakov, A E [Russian Academy of Sciences, Scientific-Technological Center for Microelectronics and Submicron Heterostructures at Ioffe Physicotechnical Institute (Russian Federation)

    2009-03-15

    Equilibrium and nonequilibrium IR images of p-InAsSbP/n-InAsSb/n{sup +}-InAs photodiodes including the images obtained in the electroluminescence and negative luminescence modes have been analyzed. The contact reflectivity has been evaluated. The influence of the substrate's doping level and mesa depth on the quantum efficiency and sensitivity of a backside illuminated photodiode sensitive in the 2.7-4.5 {mu}m range is discussed.

  18. Enhancing the far-ultraviolet sensitivity of silicon complementary metal oxide semiconductor imaging arrays

    Science.gov (United States)

    Retherford, Kurt D.; Bai, Yibin; Ryu, Kevin K.; Gregory, James A.; Welander, Paul B.; Davis, Michael W.; Greathouse, Thomas K.; Winters, Gregory S.; Suntharalingam, Vyshnavi; Beletic, James W.

    2015-10-01

    We report our progress toward optimizing backside-illuminated silicon P-type intrinsic N-type complementary metal oxide semiconductor devices developed by Teledyne Imaging Sensors (TIS) for far-ultraviolet (UV) planetary science applications. This project was motivated by initial measurements at Southwest Research Institute of the far-UV responsivity of backside-illuminated silicon PIN photodiode test structures, which revealed a promising QE in the 100 to 200 nm range. Our effort to advance the capabilities of thinned silicon wafers capitalizes on recent innovations in molecular beam epitaxy (MBE) doping processes. Key achievements to date include the following: (1) representative silicon test wafers were fabricated by TIS, and set up for MBE processing at MIT Lincoln Laboratory; (2) preliminary far-UV detector QE simulation runs were completed to aid MBE layer design; (3) detector fabrication was completed through the pre-MBE step; and (4) initial testing of the MBE doping process was performed on monitoring wafers, with detailed quality assessments.

  19. Radiation hardness investigation of avalanche photodiodes for the Projectile Spectator Detector readout at the Compressed Baryonic Matter experiment

    Czech Academy of Sciences Publication Activity Database

    Kushpil, Vasilij; Mikhaylov, Vasily; Kushpil, Svetlana; Tlustý, Pavel; Svoboda, Ondřej; Kugler, Andrej

    2015-01-01

    Roč. 787, JUL (2015), s. 117-120 ISSN 0168-9002 R&D Projects: GA MŠk LG12007; GA MŠk LG14004; GA MŠk(CZ) LM2011019 Institutional support: RVO:61389005 Keywords : avalanche photodiodes * single protons detection * radiation hardness * neutron irradiation tests * compressed Baryonic Matter experiment * Projectile Spectator Detector Subject RIV: BG - Nuclear, Atomic and Molecular Physics , Colliders Impact factor: 1.200, year: 2015

  20. Application of avalanche photodiode for soft X-ray pulse-height analyses in the Ht-7 tokamak

    CERN Document Server

    Shi Yue Jiang; Hu Li Qun; Sun Yan Jun; LiuSheng; Ling Bil

    2002-01-01

    An avalanche photodiode (APD) has been used as soft X-ray energy pulse-height analysis system for the measurement of the electron temperature on the HT-7 tokamak. The experimental results obtained with the APD with its inferior energy resolution show a little difference compared to the conventional high energy-resolution Si (Li) detector. Both numerical analysis and experimental results prove that the APD is good enough for application of the electron temperature measurement in tokamaks.

  1. Joining elements of silicon carbide

    International Nuclear Information System (INIS)

    Olson, B.A.

    1979-01-01

    A method of joining together at least two silicon carbide elements (e.g.in forming a heat exchanger) is described, comprising subjecting to sufficiently non-oxidizing atmosphere and sufficiently high temperature, material placed in space between the elements. The material consists of silicon carbide particles, carbon and/or a precursor of carbon, and silicon, such that it forms a joint joining together at least two silicon carbide elements. At least one of the elements may contain silicon. (author)

  2. Investigation of the performance of alpha particle counting and alpha-gamma discrimination by pulse shape with micro-pixel avalanche photodiode

    International Nuclear Information System (INIS)

    Ahmadov, G.; Madatov, R.; Sadigov, A.; Sadygov, Z.; Jafarova, E.; Ahmadov, G.; Sadygov, Z.; Olshevski, A.; Zerrouk, F.; Mukhtarov, R.

    2015-01-01

    Being capable measuring small lights gives possibility to use micro-pixel avalanche photodiodes with scintillators. It is shown two prototypes to use micro-pixel avalanche photodiodes with and without scintillators as alpha and gamma counters in this paper. First prototype is to use two micro-pixel avalanche photodiodes. One for detecting alpha particles and closer to it, the second one with a thin plastic scintillator for detecting gamma rays. Second prototype is called two-layers configuration in which it is used only one micro-pixel avalanche photodiode, but two scntillators with different decay times. One can distinquish alpha particle and gamma ray events by using pulse shape discrimination techniques in the two-layer configuration. In this work an alpha particle and gamma ray counting performance of micro-pixel avalanche photodiodes without scintillators and its combination of plastic and BGO+ plastic scintillators was investigated. Obtained results showed the detection performance of the micro-pixel avalanche photodiodes in combination with plastic scintillator was about the same as conventional semiconductor detectors

  3. Gamma-ray detection with an UV-enhanced photodiode and scintillation crystals emitting at short wavelengths

    International Nuclear Information System (INIS)

    Johansen, G.A.

    1997-01-01

    A low-noise ion implanted photodiode with high spectral response in the deep blue/UV region has been tested as read-out device for scintillation crystals with matching emission spectra (YAP(Ce), GSO(Ce), BGO and CsI(Tl)). This gamma-ray detector concept is attractive in many industrial applications where compactness, reliability and ambient temperature operation are important. The results show that the amount of detected scintillation light energy falls rapidly off as the wavelength of the scintillation light decreases. It is concluded that the dynamic spectral response of the photodiode, due to increasing carrier collection times, is considerably less than the DC response at short wavelengths. The diode is not useful in pulse mode operation with scintillation crystals emitting at wavelengths below about 400 nm. For read-out of CsI(Tl) with 661.6 keV gamma-radiation, however, the photodiode concept shows better energy resolution (7.1%) than other detectors. (orig.)

  4. Determination of the excess noise of avalanche photodiodes integrated in 0.35-μm CMOS technologies

    Science.gov (United States)

    Jukić, Tomislav; Brandl, Paul; Zimmermann, Horst

    2018-04-01

    The excess noise of avalanche photodiodes (APDs) integrated in a high-voltage (HV) CMOS process and in a pin-photodiode CMOS process, both with 0.35-μm structure sizes, is described. A precise excess noise measurement technique is applied using a laser source, a spectrum analyzer, a voltage source, a current meter, a cheap transimpedance amplifier, and a personal computer with a MATLAB program. In addition, usage for on-wafer measurements is demonstrated. The measurement technique is verified with a low excess noise APD as a reference device with known ratio k = 0.01 of the impact ionization coefficients. The k-factor of an APD developed in HV CMOS is determined more accurately than known before. In addition, it is shown that the excess noise of the pin-photodiode CMOS APD depends on the optical power for avalanche gains above 35 and that modulation doping can suppress this power dependence. Modulation doping, however, increases the excess noise.

  5. Photoluminescence and electrical properties of silicon oxide and silicon nitride superlattices containing silicon nanocrystals

    International Nuclear Information System (INIS)

    Shuleiko, D V; Ilin, A S

    2016-01-01

    Photoluminescence and electrical properties of superlattices with thin (1 to 5 nm) alternating silicon-rich silicon oxide or silicon-rich silicon nitride, and silicon oxide or silicon nitride layers containing silicon nanocrystals prepared by plasma-enhanced chemical vapor deposition with subsequent annealing were investigated. The entirely silicon oxide based superlattices demonstrated photoluminescence peak shift due to quantum confinement effect. Electrical measurements showed the hysteresis effect in the vicinity of zero voltage due to structural features of the superlattices from SiOa 93 /Si 3 N 4 and SiN 0 . 8 /Si 3 N 4 layers. The entirely silicon nitride based samples demonstrated resistive switching effect, comprising an abrupt conductivity change at about 5 to 6 V with current-voltage characteristic hysteresis. The samples also demonstrated efficient photoluminescence with maximum at ∼1.4 eV, due to exiton recombination in silicon nanocrystals. (paper)

  6. Advances in silicon nanophotonics

    DEFF Research Database (Denmark)

    Hvam, Jørn Märcher; Pu, Minhao

    Silicon has long been established as an ideal material for passive integrated optical circuitry due to its high refractive index, with corresponding strong optical confinement ability, and its low-cost CMOS-compatible manufacturability. However, the inversion symmetry of the silicon crystal lattice.......g. in high-bit-rate optical communication circuits and networks, it is vital that the nonlinear optical effects of silicon are being strongly enhanced. This can among others be achieved in photonic-crystal slow-light waveguides and in nano-engineered photonic-wires (Fig. 1). In this talk I shall present some...... recent advances in this direction. The efficient coupling of light between optical fibers and the planar silicon devices and circuits is of crucial importance. Both end-coupling (Fig. 1) and grating-coupling solutions will be discussed along with polarization issues. A new scheme for a hybrid III...

  7. Integrated silicon optoelectronics

    CERN Document Server

    Zimmermann, Horst

    2000-01-01

    'Integrated Silicon Optoelectronics'assembles optoelectronics and microelectronics The book concentrates on silicon as the major basis of modern semiconductor devices and circuits Starting from the basics of optical emission and absorption and from the device physics of photodetectors, the aspects of the integration of photodetectors in modern bipolar, CMOS, and BiCMOS technologies are discussed Detailed descriptions of fabrication technologies and applications of optoelectronic integrated circuits are included The book, furthermore, contains a review of the state of research on eagerly expected silicon light emitters In order to cover the topic of the book comprehensively, integrated waveguides, gratings, and optoelectronic power devices are included in addition Numerous elaborate illustrations promote an easy comprehension 'Integrated Silicon Optoelectronics'will be of value to engineers, physicists, and scientists in industry and at universities The book is also recommendable for graduate students speciali...

  8. Silicon microfabricated beam expander

    International Nuclear Information System (INIS)

    Othman, A.; Ibrahim, M. N.; Hamzah, I. H.; Sulaiman, A. A.; Ain, M. F.

    2015-01-01

    The feasibility design and development methods of silicon microfabricated beam expander are described. Silicon bulk micromachining fabrication technology is used in producing features of the structure. A high-precision complex 3-D shape of the expander can be formed by exploiting the predictable anisotropic wet etching characteristics of single-crystal silicon in aqueous Potassium-Hydroxide (KOH) solution. The beam-expander consist of two elements, a micromachined silicon reflector chamber and micro-Fresnel zone plate. The micro-Fresnel element is patterned using lithographic methods. The reflector chamber element has a depth of 40 µm, a diameter of 15 mm and gold-coated surfaces. The impact on the depth, diameter of the chamber and absorption for improved performance are discussed

  9. Silicon microfabricated beam expander

    Science.gov (United States)

    Othman, A.; Ibrahim, M. N.; Hamzah, I. H.; Sulaiman, A. A.; Ain, M. F.

    2015-03-01

    The feasibility design and development methods of silicon microfabricated beam expander are described. Silicon bulk micromachining fabrication technology is used in producing features of the structure. A high-precision complex 3-D shape of the expander can be formed by exploiting the predictable anisotropic wet etching characteristics of single-crystal silicon in aqueous Potassium-Hydroxide (KOH) solution. The beam-expander consist of two elements, a micromachined silicon reflector chamber and micro-Fresnel zone plate. The micro-Fresnel element is patterned using lithographic methods. The reflector chamber element has a depth of 40 µm, a diameter of 15 mm and gold-coated surfaces. The impact on the depth, diameter of the chamber and absorption for improved performance are discussed.

  10. Silicon microfabricated beam expander

    Energy Technology Data Exchange (ETDEWEB)

    Othman, A., E-mail: aliman@ppinang.uitm.edu.my; Ibrahim, M. N.; Hamzah, I. H.; Sulaiman, A. A. [Faculty of Electrical Engineering, Universiti Teknologi MARA Malaysia, 40450, Shah Alam, Selangor (Malaysia); Ain, M. F. [School of Electrical and Electronic Engineering, Engineering Campus, Universiti Sains Malaysia, Seri Ampangan, 14300,Nibong Tebal, Pulau Pinang (Malaysia)

    2015-03-30

    The feasibility design and development methods of silicon microfabricated beam expander are described. Silicon bulk micromachining fabrication technology is used in producing features of the structure. A high-precision complex 3-D shape of the expander can be formed by exploiting the predictable anisotropic wet etching characteristics of single-crystal silicon in aqueous Potassium-Hydroxide (KOH) solution. The beam-expander consist of two elements, a micromachined silicon reflector chamber and micro-Fresnel zone plate. The micro-Fresnel element is patterned using lithographic methods. The reflector chamber element has a depth of 40 µm, a diameter of 15 mm and gold-coated surfaces. The impact on the depth, diameter of the chamber and absorption for improved performance are discussed.

  11. Porous Silicon Nanowires

    Science.gov (United States)

    Qu, Yongquan; Zhou, Hailong; Duan, Xiangfeng

    2011-01-01

    In this minreview, we summarize recent progress in the synthesis, properties and applications of a new type of one-dimensional nanostructures — single crystalline porous silicon nanowires. The growth of porous silicon nanowires starting from both p- and n-type Si wafers with a variety of dopant concentrations can be achieved through either one-step or two-step reactions. The mechanistic studies indicate the dopant concentration of Si wafers, oxidizer concentration, etching time and temperature can affect the morphology of the as-etched silicon nanowires. The porous silicon nanowires are both optically and electronically active and have been explored for potential applications in diverse areas including photocatalysis, lithium ion battery, gas sensor and drug delivery. PMID:21869999

  12. Large area avalanche photodiodes in scintillation and X-rays detection

    International Nuclear Information System (INIS)

    Moszynski, M.; Szawlowski, M.; Kapusta, M.; Balcerzyk, M.

    2002-01-01

    The presented paper summarizes our earlier studies on application of beveled-edge Large Area Avalanche Photodiodes (LAAPDs) in γ-rays scintillation detection. LAAPDs, due to their high quantum efficiency and low excess noise factor allow for better statistical accuracy of the signal as compared to photomultipliers. The device dark noise contribution significantly affects energy resolution only for γ-rays with energy below 50 keV. Notably better or comparable energy resolutions to those observed with a XP2020Q photomultiplier were obtained with the LAAPDs for a number of different scintillators. Particularly, the recorded energy resolutions of 4.3±0.2% and 4.8±0.14% measured with YAP and CsI(Tl) crystals, respectively, for the 662 keV γ-peak from a 137 Cs source belong to the best observed ever with these scintillation detectors. Results of the study of timing with fast scintillators coupled to the LAAPD showed subnanosecond time resolution of 570±30 ps for 60 Co γ-rays detected in LSO crystal. The response of LAAPD to X-rays and factors limiting energy resolution have been discussed too

  13. Large area avalanche photodiodes in scintillation and X-rays detection

    CERN Document Server

    Moszynski, M; Kapusta, M; Balcerzyk, M

    2002-01-01

    The presented paper summarizes our earlier studies on application of beveled-edge Large Area Avalanche Photodiodes (LAAPDs) in gamma-rays scintillation detection. LAAPDs, due to their high quantum efficiency and low excess noise factor allow for better statistical accuracy of the signal as compared to photomultipliers. The device dark noise contribution significantly affects energy resolution only for gamma-rays with energy below 50 keV. Notably better or comparable energy resolutions to those observed with a XP2020Q photomultiplier were obtained with the LAAPDs for a number of different scintillators. Particularly, the recorded energy resolutions of 4.3+-0.2% and 4.8+-0.14% measured with YAP and CsI(Tl) crystals, respectively, for the 662 keV gamma-peak from a sup 1 sup 3 sup 7 Cs source belong to the best observed ever with these scintillation detectors. Results of the study of timing with fast scintillators coupled to the LAAPD showed subnanosecond time resolution of 570+-30 ps for sup 6 sup 0 Co gamma-ray...

  14. Characterization and quality control of avalanche photodiode arrays for the Clear-PEM detector modules

    International Nuclear Information System (INIS)

    Abreu, Conceicao; Amaral, Pedro; Carrico, Bruno; Ferreira, Miguel; Luyten, Joan; Moura, Rui; Ortigao, Catarina; Rato, Pedro; Varela, Joao

    2007-01-01

    Clear-PEM is a Positron Emission Mammography (PEM) prototype being developed in the framework of the Crystal Clear Collaboration at CERN. This device is a dedicated PET camera for mammography, based on LYSO:Ce scintillator crystals, Avalanche PhotoDiodes (APD) and a fast, low-noise electronics readout system, designed to examine both the breast and the axillary lymph node areas, and aiming at the detection of tumors down to 2 mm in diameter. The prototype has two planar detector heads, each composed of 96 detector modules. The Clear-PEM detector module is composed of a matrix of 32 identical 2x2x20 mm 3 LYSO:Ce crystals read at both ends by Hamamatsu S8550 APD arrays (4x8) for Depth-of-Interaction (DoI) capability. The APD arrays were characterized by the measurement of gain and dark current as a function of bias voltage, under controlled temperature conditions. Two independent setups were used. The full set of 398 APD arrays followed a well-defined quality control (QC) protocol, aiming at the rejection of arrays not complying within defined specifications. From a total of 398 arrays, only 2 (0.5%) were rejected, reassuring the trust in these detectors for prototype assembly and future developments

  15. Readout of plastic scintillators with cooled large-area avalanche photodiodes

    Energy Technology Data Exchange (ETDEWEB)

    Mykulyak, A.; Kapusta, M.; Lynen, U.; Moszynski, M.; Mueller, W.F.J.; Orth, H.; Schwarz, C.; Szawlowski, M.; Trautmann, W.; Trzcinski, A.; Wolski, D.; Zwieglinski, B. E-mail: bzw@fuw.edu.pl

    2004-05-11

    Time-of-flight measurements in multifragmentation of heavy, relativistic projectiles require very good time resolution and at the same time the detecting system must cope with a dynamic range of up to 8000:1. We look into the possibility of application of large-area avalanche photodiodes (LAAPDs) as alternative light sensors to meet the above requirements. The paper presents the results of our amplitude and time response studies of a plastic scintillator BC-408 readout with a phi16 mm LAAPD using radioactive sources. The measurements were performed using two different setups. The best time resolution has been obtained by exploiting LAAPD cooling to increase its gain beyond that accessible at room temperature. We reach 610 ps (FWHM) at -26 deg. C for the corresponding LAAPD gain of {approx}900 and the {sup 90}Sr/{sup 90}Y {beta}-ray source. We hope to reach below the desired 400 ps with the latter setup at the higher light levels available with multifragmentation products.

  16. Photodiode Based on CdO Thin Films as Electron Transport Layer

    Science.gov (United States)

    Soylu, M.; Kader, H. S.

    2016-11-01

    Cadmium oxide (CdO) thin films were synthesized by the sol-gel method. The films were analyzed by means of XRD, AFM, and UV/Vis spectrophotometry. X-ray diffraction patterns confirm that the films are formed from CdO with cubic crystal structure and consist of nano-particles. The energy gap of the prepared film was found to be 2.29 eV. The current-voltage ( I- V) characteristics of the CdO/ p-Si heterojunction were examined in the dark and under different illumination intensities. The heterojunction showed high rectifying behavior and a strong photoresponse. Main electrical parameters of the photodiode such as series and shunt resistances ( R s and R sh), saturation current I 0, and photocurrent I ph, were extracted considering a single diode equivalent circuit of a photovoltaic cell. Results indicate that the application of CdO thin films as an electron transport layer on p-Si acts as a photodetector in the field of the UV/visible.

  17. Research on photodiode detector-based spatial transient light detection and processing system

    Science.gov (United States)

    Liu, Meiying; Wang, Hu; Liu, Yang; Zhao, Hui; Nan, Meng

    2016-10-01

    In order to realize real-time signal identification and processing of spatial transient light, the features and the energy of the captured target light signal are first described and quantitatively calculated. Considering that the transient light signal has random occurrence, a short duration and an evident beginning and ending, a photodiode detector based spatial transient light detection and processing system is proposed and designed in this paper. This system has a large field of view and is used to realize non-imaging energy detection of random, transient and weak point target under complex background of spatial environment. Weak signal extraction under strong background is difficult. In this paper, considering that the background signal changes slowly and the target signal changes quickly, filter is adopted for signal's background subtraction. A variable speed sampling is realized by the way of sampling data points with a gradually increased interval. The two dilemmas that real-time processing of large amount of data and power consumption required by the large amount of data needed to be stored are solved. The test results with self-made simulative signal demonstrate the effectiveness of the design scheme. The practical system could be operated reliably. The detection and processing of the target signal under the strong sunlight background was realized. The results indicate that the system can realize real-time detection of target signal's characteristic waveform and monitor the system working parameters. The prototype design could be used in a variety of engineering applications.

  18. Progress in the use of avalanche photodiodes for readout for calorimeters

    International Nuclear Information System (INIS)

    Fenker, H.; Morgan, K.; Regan, T.

    1991-09-01

    During the past year the Superconducting Super Collider Tracking Group has progressed from acquisition of its first avalanche photodiode (APD) to installation of a 96-channel array of the devices. The work was motivated by the desire to learn how to use APDs as the sensitive elements in a fiber tracking detector, moderated by the presence of limited resources and the absence of activity within groups outside the SSC Laboratory on such a project. We chose, therefore, to team up with an ongoing research effort which intended to evaluate both pre-shower and shower-maximum detectors and various means of sensing the light produced. The pre-shower detector is made of layers of scintillating fibers similar to a fiber tracker. The shower-maximum detector uses optical fibers to transmit the light from scintillating plates to the readout devices. Our contribution has been to develop the APD array for use in this test from concept to operation. Currently, the equipment is installed in Fermilab's MP beamline awaiting delivery to the final 36 APDs and exposure to the beam. 9 refs., 18 figs

  19. Anomalous Photovoltaic Response of Graphene-on-GaN Schottky Photodiodes.

    Science.gov (United States)

    Lee, Jae Hyung; Lee, Won Woo; Yang, Dong Won; Chang, Won Jun; Kwon, Sun Sang; Park, Won Il

    2018-04-25

    Graphene has attracted great attention as an alternative to conventional metallic or transparent conducting electrodes. Despite its similarities with conventional electrodes, recent studies have shown that a single-atom layer of graphene possesses unique characteristics, such as a tunable work function and transparencies for electric potential, reactivity, and wetting. Nevertheless, a systematic analysis of graphene and semiconductor junction characteristics has not yet been carried out. Here, we report the photoresponse characteristics of graphene-on-GaN Schottky junction photodiodes (Gr-GaN SJPDs), showing a typical rectifying behavior and distinct photovoltaic and photoelectric responses. Following the initial abrupt response to UV illumination, the Gr-GaN SJPDs exhibited a distinct difference in photocarrier dynamics depending on the applied bias voltage, which is characterized by either a negative or positive change in photocurrent with time. We propose underlying mechanisms for the anomalous photocarrier dynamics based on the interplay between electrostatic molecular interactions over the one-atom-thick graphene and GaN junction and trapped photocarriers at the defect states in the GaN thin film.

  20. Prototype for the measurement of parameters in the Mammography Unity using photodiodes

    International Nuclear Information System (INIS)

    Mercado H, I.; Ramirez J, F.J.; Tovar M, V.; Becerril V, A.

    1999-01-01

    It has been developed a prototype which makes possible to measure the kilo voltage applied to the X-ray tube, the exposure time of the radiation beam and the yield expressed in kerma in air K a (mGy/m As) o a mammography unit. The instrument consists of a radiation detector, an acquisition circuit, a stage of analogical processing of the signal connected to an analogic-digital converter and a display system of the results. The detection section is composed by a pair of photodiodes PIN type in which to do make the measurement of kilo voltage one of them is covered by an aluminium filter (Al) and the other one by a molybdenum filter (Mo). The measurements were done in a mammography unit which possess a generator of high frequency, with a molybdenum anode, a window 8 mm Beryllium (Be) and an additional filtration of 30 μ m Mo. The measurements obtained were compared with commercial instruments finding maximum variations of 2 % of value obtained. This prototype has been developed with the idea to obtain in a future a commercial instrument, for be used mainly in the hospitable institutions as an auxiliary tool in the Quality assurance programs in radiodiagnostic. (Author)

  1. Update on Linear Mode Photon Counting with the HgCdTe Linear Mode Avalanche Photodiode

    Science.gov (United States)

    Beck, Jeffrey D.; Kinch, Mike; Sun, Xiaoli

    2014-01-01

    The behavior of the gain-voltage characteristic of the mid-wavelength infrared cutoff HgCdTe linear mode avalanche photodiode (e-APD) is discussed both experimentally and theoretically as a function of the width of the multiplication region. Data are shown that demonstrate a strong dependence of the gain at a given bias voltage on the width of the n- gain region. Geometrical and fundamental theoretical models are examined to explain this behavior. The geometrical model takes into account the gain-dependent optical fill factor of the cylindrical APD. The theoretical model is based on the ballistic ionization model being developed for the HgCdTe APD. It is concluded that the fundamental theoretical explanation is the dominant effect. A model is developed that combines both the geometrical and fundamental effects. The model also takes into account the effect of the varying multiplication width in the low bias region of the gain-voltage curve. It is concluded that the lower than expected gain seen in the first 2 × 8 HgCdTe linear mode photon counting APD arrays, and higher excess noise factor, was very likely due to the larger than typical multiplication region length in the photon counting APD pixel design. The implications of these effects on device photon counting performance are discussed.

  2. Single-Photon-Sensitive HgCdTe Avalanche Photodiode Detector

    Science.gov (United States)

    Huntington, Andrew

    2013-01-01

    The purpose of this program was to develop single-photon-sensitive short-wavelength infrared (SWIR) and mid-wavelength infrared (MWIR) avalanche photodiode (APD) receivers based on linear-mode HgCdTe APDs, for application by NASA in light detection and ranging (lidar) sensors. Linear-mode photon-counting APDs are desired for lidar because they have a shorter pixel dead time than Geiger APDs, and can detect sequential pulse returns from multiple objects that are closely spaced in range. Linear-mode APDs can also measure photon number, which Geiger APDs cannot, adding an extra dimension to lidar scene data for multi-photon returns. High-gain APDs with low multiplication noise are required for efficient linear-mode detection of single photons because of APD gain statistics -- a low-excess-noise APD will generate detectible current pulses from single photon input at a much higher rate of occurrence than will a noisy APD operated at the same average gain. MWIR and LWIR electron-avalanche HgCdTe APDs have been shown to operate in linear mode at high average avalanche gain (M > 1000) without excess multiplication noise (F = 1), and are therefore very good candidates for linear-mode photon counting. However, detectors fashioned from these narrow-bandgap alloys require aggressive cooling to control thermal dark current. Wider-bandgap SWIR HgCdTe APDs were investigated in this program as a strategy to reduce detector cooling requirements.

  3. Optimization of eyesafe avalanche photodiode lidar for automobile safety and autonomous navigation systems

    Science.gov (United States)

    Williams, George M.

    2017-03-01

    Newly emerging accident-reducing, driver-assistance, and autonomous-navigation technology for automobiles is based on real-time three-dimensional mapping and object detection, tracking, and classification using lidar sensors. Yet, the lack of lidar sensors suitable for meeting application requirements appreciably limits practical widespread use of lidar in trucking, public livery, consumer cars, and fleet automobiles. To address this need, a system-engineering perspective to eyesafe lidar-system design for high-level advanced driver-assistance sensor systems and a design trade study including 1.5-μm spot-scanned, line-scanned, and flash-lidar systems are presented. A cost-effective lidar instrument design is then proposed based on high-repetition-rate diode-pumped solid-state lasers and high-gain, low-excess-noise InGaAs avalanche photodiode receivers and focal plane arrays. Using probabilistic receiver-operating-characteristic analysis, derived from measured component performance, a compact lidar system is proposed that is capable of 220 m ranging with 5-cm accuracy, which can be readily scaled to a 360-deg field of regard.

  4. Evaluation of Space Radiation Effects on HgCdTe Avalanche Photodiode Arrays for Lidar Applications

    Science.gov (United States)

    Sun, Xiaoli; Abshire, James B.; Lauenstein, Jean-Marie; Sullivan, William III; Beck, Jeff; Hubbs, John E.

    2018-01-01

    We report the results from proton and gamma ray radiation testing of HgCdTe avalanche photodiode (APD) arrays developed by Leonardo DRS for space lidar detectors. We tested these devices with both approximately 60 MeV protons and gamma rays, with and without the read out integrated circuit (ROIC). We also measured the transient responses with the device fully powered and with the APD gain from unity to greater than 1000. The detectors produced a large current impulse in response to each proton hit but the response completely recovered within 1 microsecond. The devices started to have persistent damage at a proton fluence of 7e10 protons/cm2, equivalent to 10 krad(Si) total ionization dose. The dark current became much higher after the device was warmed to room temperature and cooled to 80K again, but it completely annealed after baking at 85 C for several hours. These results showed the HgCdTe APD arrays are suitable for use in space lidar for typical Earth orbiting and planetary missions provided that provisions are made to heat the detector chip to 85 C for several hours after radiation damage becomes evident that system performance is impacted.

  5. Measurement of environmental radioactivity with photo-diode and Imaging Plate

    International Nuclear Information System (INIS)

    Mori, C.; Sumi, T.; Gotoh, S.; Saze, T.; Nishizawa, K.

    2000-01-01

    Measurement of environmental radioactivity with photo-diode (PD) and Imaging Plate (IP) was tired. Commercially available Si PIN type PD's generally have depletion layer thickness more than a few hundred micrometer, which is enough for alpha particle measurement. PD's have various features: being usable in normal temperature, high energy resolution and low cost. Radon daughter nuclides positively charged in atmosphere were collected on the PD surface with negative electric potential and measured the pulse height spectra of alpha-particles from the daughter nuclides of Radon in thorium oxide, uranium ore, granite, and concrete. Counting of alpha-particles with IP was tired. Lead plates usually contain Pb-210 (RaD) and emit alpha-particles from Po-210. The alpha-particles from the plate were counted with PD and the plate was exposed to IP. By adjusting the gradation level on the reading out of the latent image, it was possible to count alpha-particle incident image one by one, and the number per 1 cm 2 was compared with the number of count with PD. (author)

  6. Performance Analysis of OCDMA Based on AND Detection in FTTH Access Network Using PIN & APD Photodiodes

    Science.gov (United States)

    Aldouri, Muthana; Aljunid, S. A.; Ahmad, R. Badlishah; Fadhil, Hilal A.

    2011-06-01

    In order to comprise between PIN photo detector and avalanche photodiodes in a system used double weight (DW) code to be a performance of the optical spectrum CDMA in FTTH network with point-to-multi-point (P2MP) application. The performance of PIN against APD is compared through simulation by using opt system software version 7. In this paper we used two networks designed as follows one used PIN photo detector and the second using APD photo diode, both two system using with and without erbium doped fiber amplifier (EDFA). It is found that APD photo diode in this system is better than PIN photo detector for all simulation results. The conversion used a Mach-Zehnder interferometer (MZI) wavelength converter. Also we are study, the proposing a detection scheme known as AND subtraction detection technique implemented with fiber Bragg Grating (FBG) act as encoder and decoder. This FBG is used to encode and decode the spectral amplitude coding namely double weight (DW) code in Optical Code Division Multiple Access (OCDMA). The performances are characterized through bit error rate (BER) and bit rate (BR) also the received power at various bit rate.

  7. Application of An Avalanche Photodiode in Synchrotron-Based Ultra-fast X-Radiography

    International Nuclear Information System (INIS)

    Cheong, S.-K.; Liu Jinyuan; Wang Jin; Powell, Christopher F.

    2004-01-01

    A possibility of using avalanche photodiode has been investigated while operated in current or continuous wave mode to accommodate high-intensity synchrotron x-ray beams in an ultra-fast x-radiography. To achieve a time resolution of 1 μs or better in a time-resolved x-radiograhic experiment, the entire time-sequence of the APD response to the pulsed synchrotron x-ray beam is recorded with time resolution of 1-2 ns. We have characterized the APD detector in the continuous wave mode to reveal its linearity, signal to noise ratio, and the time response with various circuit configurations. We have demonstrated that signal-to-noise ratio better than 1000 can be achieved, which is limited only by Poisson statistics. These detectors, coupled with finely focused x-rays, have been used to study structure and dynamics of supersonic fuel sprays with 50 μm-spatial resolution and μs-temporal resolution in the region close to an injection nozzle

  8. Comparison between Conventional OCDMA and Subcarrier Multiplexing SAC OCDMA System Based on Single Photodiode Detection

    Directory of Open Access Journals (Sweden)

    Ahmad N. A. A

    2017-01-01

    Full Text Available This paper demonstrates the comparison between conventional OCDMA system and subcarrier multiplexing (SCM SAC-OCDMA system by applying Recursive Combinatorial (RC code based on single photodiode detection (SPD. SPD is used in the receiver part to reduce the effect of multiple access interference (MAI which contributes as a dominant noise in incoherent SAC-OCDMA systems. From this analysis, the performance of SCM OCDMA network could be improved by using lower data rates and higher received power. The hybrid SCM OCDMA system shows better performance compare to conventional OCDMA system although the number of users involved is very high. This is because, for hybrid SCM OCDMA system, the number of users can be increased by increasing the number of subcarriers without affect the number of code length and optical codes. Increasing the number of subcarriers will enhance the power consumption by applying hybrid SCM system in OCDMA compared to the conventional OCDMA system. This is because increasing the number of users for hybrid SCM system does not affects the number of code length and the number of optical codes but only increase the number of subcarriers. Thus, hybrid SCM OCDMA system has to increase spectral efficiency and produce better performance compared to conventional of OCDMA system.

  9. Simultaneous multi-element atomic absorption system using photodiode array detector

    International Nuclear Information System (INIS)

    Tong, S.L.; Chin, K.S.

    1994-01-01

    A photodiode array (PDA) detector-multichannel analyser (MCA) system has been coupled to a flame and a graphite furnace atomiser and tested for simultaneous multielement atomic absorption analysis. Multielement hollow cathode lamps (HCL) are used as light source. Spectral lines are dispersed through a spectrograph with triple gratings and detected by a 25.4 mm PDA detector consisting of 1024 elements. The optical MCA system is capable of recording multiple spectra spanned by the spectrograph/PDA. The transmitted intensity spectra obtained for the standard and analyte solutions during flame or graphite furnace atomisation are converted to absorbance spectra using the MCA software provided. Results from the comparison studies show that the linear range and sensitivities for Ni-Co-Fe and Cu-Cr obtained from the simultaneous measurements are within the same order of magnitudes as those from conventional single element determinations using photomultiplier tube detection. The study also shows that non-atomic absorption can be readily corrected by a two-line method where non-atomic absorption lines can be chosen from the spectra recorded simultaneously. The proposed system has been evaluated for the determination of trace elements using NBS standard reference water SRM 1643b

  10. Investigation of Avalanche Photodiodes and Multipixel Photon Counters as Light Detectors for Cosmic Rays

    Science.gov (United States)

    Vasquez, Jaime; Saavedra, Arthur; Ramos, Roxana; Tavares, Pablo; Wade, Marcus; Fan, Sewan; Haag, Brooke

    2013-04-01

    Through the Research Scholars Institute, students of Hartnell Community College experimented with the application of avalanche photodiodes (APDs) as cosmic ray detectors during the summer of 2012. An APD detector was coupled with a 10 meter long wavelength shifting fiber (WSF) wrapped around a cylindrical plastic scintillator to maximize signal detection. A photomultiplier tube (PMT) was used in conjunction to detect the same scintillation light caused by incoming cosmic rays. Two APD detectors were evaluated to confirm the viability of the setup. In addition, a similar setup was recently utilized to implement multi-pixel photon counters (MPPCs) as readout detectors. Under this configuration, a high gain preamplifier was used to amplify the signals for both the MPPC and APD detectors. We report on our results characterizing the MPPC and discuss its overall performance. Compared to the APD, our findings suggest that the MPPC detector has greater sensitivity in detecting weak light signals, and can be used in place of the PMT for certain counting applications.

  11. Thin-Film Quantum Dot Photodiode for Monolithic Infrared Image Sensors.

    Science.gov (United States)

    Malinowski, Pawel E; Georgitzikis, Epimitheas; Maes, Jorick; Vamvaka, Ioanna; Frazzica, Fortunato; Van Olmen, Jan; De Moor, Piet; Heremans, Paul; Hens, Zeger; Cheyns, David

    2017-12-10

    Imaging in the infrared wavelength range has been fundamental in scientific, military and surveillance applications. Currently, it is a crucial enabler of new industries such as autonomous mobility (for obstacle detection), augmented reality (for eye tracking) and biometrics. Ubiquitous deployment of infrared cameras (on a scale similar to visible cameras) is however prevented by high manufacturing cost and low resolution related to the need of using image sensors based on flip-chip hybridization. One way to enable monolithic integration is by replacing expensive, small-scale III-V-based detector chips with narrow bandgap thin-films compatible with 8- and 12-inch full-wafer processing. This work describes a CMOS-compatible pixel stack based on lead sulfide quantum dots (PbS QD) with tunable absorption peak. Photodiode with a 150-nm thick absorber in an inverted architecture shows dark current of 10 -6 A/cm² at -2 V reverse bias and EQE above 20% at 1440 nm wavelength. Optical modeling for top illumination architecture can improve the contact transparency to 70%. Additional cooling (193 K) can improve the sensitivity to 60 dB. This stack can be integrated on a CMOS ROIC, enabling order-of-magnitude cost reduction for infrared sensors.

  12. Configurable Electronics with Low Noise and 14-bit Dynamic Range for Photodiode-based Photon Detectors

    CERN Document Server

    Müller, H; Yin, Z; Zhou, D; Cao, X; Li, Q; Liu, Y; Zou, F; Skaali, B; Awes, T C

    2006-01-01

    We describe the principles and measured performance characteristics of custom configurable 32-channel shaper/digitizer Front End Electronics (FEE) cards with 14-bit dynamic range for use with gain-adjustable photon detectors. The electronics has been designed for the PHOS calorimeter of ALICE with avalanche photodiode (APD) readout operated at -25 C ambient temperature and a signal shaping time of $1 {\\mu}s$. The electronics has also been adopted by the EMCal detector of ALICE with the same APD readout, but operated at an ambient temperature of +20 C and with a shaping time of 100ns. The CR-RC2 signal shapers on the FEE cards are implemented in discrete logic on a 10-layer board with two shaper sections for each input channel. The two shaper sections with gain ratio of 16:1 are digitized by 10-bit ADCs and provide an effective dynamic range of 14 bits. Gain adjustment for each individual APD is available through 32 bias voltage control registers of 10-bit range. The fixed gains and shaping times of the pole-z...

  13. Photodiode read-out of the ALICE photon spectrometer $PbWO_{4}$ crystals

    CERN Document Server

    Man'ko, V I; Sibiryak, Yu; Volkov, M; Klovning, A; Maeland, O A; Odland, O H; Rongved, R; Skaali, B

    1999-01-01

    Proposal of abstract for LEB99, Snowmass, Colorado, 20-24 September 1999The PHOton Spectrometer of the ALICE experiment is an electromagnetic calorimeter of high granularity consisting of 17280 lead-tungstate (PWO) crystals of dimensions 22x22x180 mm3, read out by large-area PIN-diodes with very low-noise front-end electronics. The crystal assembly is operated at -25C to increase the PWO light yield. A 16.1x17.1 mm2 photodiode, optimized for the PWO emissio spectrum at 400-500 nm, has been developed. The 20x20 mm2 preamplifier PCB is attached to the back side of the diode ceramic frame. The charge sensitive preamplifier is built in discrete logic with two input JFETs for optimum matching with the ~150pF PIN-diode. A prototype shaper has been designed and built in discrete logic. For a detector matrix of 64 units the measured ENCs are between 450-550e at -25C. Beam tests demonstrate that the required energy resolution is reached.Summary:The PHOton Spectrometer of the ALICE experiment is an electromagnetic calo...

  14. HIGH-SPEED IMAGING AND WAVEFRONT SENSING WITH AN INFRARED AVALANCHE PHOTODIODE ARRAY

    Energy Technology Data Exchange (ETDEWEB)

    Baranec, Christoph; Atkinson, Dani; Hall, Donald; Jacobson, Shane; Chun, Mark [Institute for Astronomy, University of Hawai‘i at Mānoa, Hilo, HI 96720-2700 (United States); Riddle, Reed [Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Law, Nicholas M., E-mail: baranec@hawaii.edu [Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3255 (United States)

    2015-08-10

    Infrared avalanche photodiode (APD) arrays represent a panacea for many branches of astronomy by enabling extremely low-noise, high-speed, and even photon-counting measurements at near-infrared wavelengths. We recently demonstrated the use of an early engineering-grade infrared APD array that achieves a correlated double sampling read noise of 0.73 e{sup −} in the lab, and a total noise of 2.52 e{sup −} on sky, and supports simultaneous high-speed imaging and tip-tilt wavefront sensing with the Robo-AO visible-light laser adaptive optics (AO) system at the Palomar Observatory 1.5 m telescope. Here we report on the improved image quality simultaneously achieved at visible and infrared wavelengths by using the array as part of an image stabilization control loop with AO-sharpened guide stars. We also discuss a newly enabled survey of nearby late M-dwarf multiplicity, as well as future uses of this technology in other AO and high-contrast imaging applications.

  15. Nanostructured silicon for thermoelectric

    Science.gov (United States)

    Stranz, A.; Kähler, J.; Waag, A.; Peiner, E.

    2011-06-01

    Thermoelectric modules convert thermal energy into electrical energy and vice versa. At present bismuth telluride is the most widely commercial used material for thermoelectric energy conversion. There are many applications where bismuth telluride modules are installed, mainly for refrigeration. However, bismuth telluride as material for energy generation in large scale has some disadvantages. Its availability is limited, it is hot stable at higher temperatures (>250°C) and manufacturing cost is relatively high. An alternative material for energy conversion in the future could be silicon. The technological processing of silicon is well advanced due to the rapid development of microelectronics in recent years. Silicon is largely available and environmentally friendly. The operating temperature of silicon thermoelectric generators can be much higher than of bismuth telluride. Today silicon is rarely used as a thermoelectric material because of its high thermal conductivity. In order to use silicon as an efficient thermoelectric material, it is necessary to reduce its thermal conductivity, while maintaining high electrical conductivity and high Seebeck coefficient. This can be done by nanostructuring into arrays of pillars. Fabrication of silicon pillars using ICP-cryogenic dry etching (Inductive Coupled Plasma) will be described. Their uniform height of the pillars allows simultaneous connecting of all pillars of an array. The pillars have diameters down to 180 nm and their height was selected between 1 micron and 10 microns. Measurement of electrical resistance of single silicon pillars will be presented which is done in a scanning electron microscope (SEM) equipped with nanomanipulators. Furthermore, measurement of thermal conductivity of single pillars with different diameters using the 3ω method will be shown.

  16. Study on Silicon detectors

    International Nuclear Information System (INIS)

    Gervino, G.; Boero, M.; Manfredotti, C.; Icardi, M.; Gabutti, A.; Bagnolatti, E.; Monticone, E.

    1990-01-01

    Prototypes of Silicon microstrip detectors and Silicon large area detectors (3x2 cm 2 ), realized directly by our group, either by ion implantation or by diffusion are presented. The physical detector characteristics and their performances determined by exposing them to different radioactive sources and the results of extensive tests on passivation, where new technological ways have been investigated, are discussed. The calculation of the different terms contributing to the total dark current is reported

  17. MUST: A silicon strip detector array for radioactive beam experiments

    International Nuclear Information System (INIS)

    Blumenfeld, Y.; Auger, F.; Sauvestre, J.E.; Marechal, F.; Ottini, S.; Alamanos, N.; Barbier, A.; Beaumel, D.; Bonnereau, B.; Charlet, D.; Clavelin, J.F.; Courtat, P.; Delbourgo-Salvador, P.; Douet, R.; Engrand, M.; Ethvignot, T.; Gillibert, A.; Khan, E.; Lapoux, V.; Lagoyannis, A.; Lavergne, L.; Lebon, S.; Lelong, P.; Lesage, A.; Le Ven, V.; Lhenry, I.; Martin, J.M.; Musumarra, A.; Pita, S.; Petizon, L.; Pollacco, E.; Pouthas, J.; Richard, A.; Rougier, D.; Santonocito, D.; Scarpaci, J.A.; Sida, J.L.; Soulet, C.; Stutzmann, J.S.; Suomijaervi, T.; Szmigiel, M.; Volkov, P.; Voltolini, G.

    1999-01-01

    A new and innovative array, MUST, based on silicon strip technology and dedicated to the study of reactions induced by radioactive beams on light particles is described. The detector consists of 8 silicon strip - Si(Li) telescopes used to identify recoiling light charged particles through time of flight, energy loss and energy measurements and to determine precisely their scattering angle through X, Y position measurements. Each 60x60 mm 2 double sided silicon strip detector with 60 vertical and 60 horizontal strips yields an X-Y position resolution of 1 mm, an energy resolution of 50 keV, a time resolution of around 1 ns and a 500 keV energy threshold for protons. The backing Si(Li) detectors stop protons up to 25 MeV with a resolution of approximately 50 keV. CsI crystals read out by photo-diodes which stop protons up to 70 MeV are added to the telescopes for applications where higher energy particles need to be detected. The dedicated electronics in VXIbus standard allow us to house the 968 logic and analog channels of the array in one crate placed adjacent to the reaction chamber and fully remote controlled, including pulse visualization on oscilloscopes. A stand alone data acquisition system devoted to the MUST array has been developed. Isotope identification of light charged particles over the full energy range has been achieved, and the capability of the system to measure angular distributions of states populated in inverse kinematics reactions has been demonstrated

  18. Subwavelength silicon photonics

    International Nuclear Information System (INIS)

    Cheben, P.; Bock, P.J.; Schmid, J.H.; Lapointe, J.; Janz, S.; Xu, D.-X.; Densmore, A.; Delage, A.; Lamontagne, B.; Florjanczyk, M.; Ma, R.

    2011-01-01

    With the goal of developing photonic components that are compatible with silicon microelectronic integrated circuits, silicon photonics has been the subject of intense research activity. Silicon is an excellent material for confining and manipulating light at the submicrometer scale. Silicon optoelectronic integrated devices have the potential to be miniaturized and mass-produced at affordable cost for many applications, including telecommunications, optical interconnects, medical screening, and biological and chemical sensing. We review recent advances in silicon photonics research at the National Research Council Canada. A new type of optical waveguide is presented, exploiting subwavelength grating (SWG) effect. We demonstrate subwavelength grating waveguides made of silicon, including practical components operating at telecom wavelengths: input couplers, waveguide crossings and spectrometer chips. SWG technique avoids loss and wavelength resonances due to diffraction effects and allows for single-mode operation with direct control of the mode confinement by changing the refractive index of a waveguide core over a range as broad as 1.6 - 3.5 simply by lithographic patterning. The light can be launched to these waveguides with a coupling loss as small as 0.5 dB and with minimal wavelength dependence, using coupling structures similar to that shown in Fig. 1. The subwavelength grating waveguides can cross each other with minimal loss and negligible crosstalk which allows massive photonic circuit connectivity to overcome the limits of electrical interconnects. These results suggest that the SWG waveguides could become key elements for future integrated photonic circuits. (authors)

  19. Silicon microphotonic waveguides

    International Nuclear Information System (INIS)

    Ta'eed, V.; Steel, M.J.; Grillet, C.; Eggleton, B.; Du, J.; Glasscock, J.; Savvides, N.

    2004-01-01

    Full text: Silicon microphotonic devices have been drawing increasing attention in the past few years. The high index-difference between silicon and its oxide (Δn = 2) suggests a potential for high-density integration of optical functions on to a photonic chip. Additionally, it has been shown that silicon exhibits strong Raman nonlinearity, a necessary property as light interaction can occur only by means of nonlinearities in the propagation medium. The small dimensions of silicon waveguides require the design of efficient tapers to couple light to them. We have used the beam propagation method (RSoft BeamPROP) to understand the principles and design of an inverse-taper mode-converter as implemented in several recent papers. We report on progress in the design and fabrication of silicon-based waveguides. Preliminary work has been conducted by patterning silicon-on-insulator (SOI) wafers using optical lithography and reactive ion etching. Thus far, only rib waveguides have been designed, as single-mode ridge-waveguides are beyond the capabilities of conventional optical lithography. We have recently moved to electron beam lithography as the higher resolutions permitted will provide the flexibility to begin fabricating sub-micron waveguides

  20. Amorphous silicon crystalline silicon heterojunction solar cells

    CERN Document Server

    Fahrner, Wolfgang Rainer

    2013-01-01

    Amorphous Silicon/Crystalline Silicon Solar Cells deals with some typical properties of heterojunction solar cells, such as their history, the properties and the challenges of the cells, some important measurement tools, some simulation programs and a brief survey of the state of the art, aiming to provide an initial framework in this field and serve as a ready reference for all those interested in the subject. This book helps to "fill in the blanks" on heterojunction solar cells. Readers will receive a comprehensive overview of the principles, structures, processing techniques and the current developmental states of the devices. Prof. Dr. Wolfgang R. Fahrner is a professor at the University of Hagen, Germany and Nanchang University, China.

  1. Oxygen defect processes in silicon and silicon germanium

    KAUST Repository

    Chroneos, A.; Sgourou, E. N.; Londos, C. A.; Schwingenschlö gl, Udo

    2015-01-01

    Silicon and silicon germanium are the archetypical elemental and alloy semiconductor materials for nanoelectronic, sensor, and photovoltaic applications. The investigation of radiation induced defects involving oxygen, carbon, and intrinsic defects is important for the improvement of devices as these defects can have a deleterious impact on the properties of silicon and silicon germanium. In the present review, we mainly focus on oxygen-related defects and the impact of isovalent doping on their properties in silicon and silicon germanium. The efficacy of the isovalent doping strategies to constrain the oxygen-related defects is discussed in view of recent infrared spectroscopy and density functional theory studies.

  2. Colloidal characterization of ultrafine silicon carbide and silicon nitride powders

    Science.gov (United States)

    Whitman, Pamela K.; Feke, Donald L.

    1986-01-01

    The effects of various powder treatment strategies on the colloid chemistry of aqueous dispersions of silicon carbide and silicon nitride are examined using a surface titration methodology. Pretreatments are used to differentiate between the true surface chemistry of the powders and artifacts resulting from exposure history. Silicon nitride powders require more extensive pretreatment to reveal consistent surface chemistry than do silicon carbide powders. As measured by titration, the degree of proton adsorption from the suspending fluid by pretreated silicon nitride and silicon carbide powders can both be made similar to that of silica.

  3. Oxygen defect processes in silicon and silicon germanium

    KAUST Repository

    Chroneos, A.

    2015-06-18

    Silicon and silicon germanium are the archetypical elemental and alloy semiconductor materials for nanoelectronic, sensor, and photovoltaic applications. The investigation of radiation induced defects involving oxygen, carbon, and intrinsic defects is important for the improvement of devices as these defects can have a deleterious impact on the properties of silicon and silicon germanium. In the present review, we mainly focus on oxygen-related defects and the impact of isovalent doping on their properties in silicon and silicon germanium. The efficacy of the isovalent doping strategies to constrain the oxygen-related defects is discussed in view of recent infrared spectroscopy and density functional theory studies.

  4. Inexpensive Mie scattering experiment for the classroom manufactured by 3D printing

    International Nuclear Information System (INIS)

    Scholz, Christian; Sack, Achim; Heckel, Michael; Pöschel, Thorsten

    2016-01-01

    Scattering experiments are fundamental for structure analysis of matter on molecular, atomic and sub-atomic length scales. In contrast, it is not standard to demonstrate optical scattering experiments on the undergraduate level beyond simple diffraction gratings. We present an inexpensive Mie scattering setup manufactured with 3D printing and open hardware. The experiment can be used to determine the particle size in dilute monodisperse colloidal suspensions with surprisingly high accuracy and is, thus, suitable to demonstrate relations between scattering measurements and microscopic properties of particles within undergraduate lab course projects. (paper)

  5. Fiber-optic sensors for rapid, inexpensive characterization of soil and ground water contamination

    International Nuclear Information System (INIS)

    Milanovich, F.P.; Yow, J.L. Jr.

    1994-08-01

    The extent and complexity of worldwide environmental contamination are great enough that characterization, remediation, and performance monitoring will be extremely costly and lengthy. Characterization techniques that are rapid, inexpensive, and simple and that do not generate waste are urgently needed. Towards this end LLNL is developing a fiber-optic chemical sensor technology for use in groundwater and vadose-zone monitoring. We use a colorimetric detection technique, based on an irreversible chemical reaction between a specific reagent and the target compound. The accuracy and sensitivity of the sensor (<5 ppb by weight in water, determined by comparison with gas chromatographic standard measurements) are sufficient for environmental monitoring of trichloroethylene (TCE) and chloroform

  6. An efficient, robust, and inexpensive grinding device for herbal samples like Cinchona bark

    DEFF Research Database (Denmark)

    Hansen, Steen Honoré; Holmfred, Else Skovgaard; Cornett, Claus

    2015-01-01

    An effective, robust, and inexpensive grinding device for the grinding of herb samples like bark and roots was developed by rebuilding a commercially available coffee grinder. The grinder was constructed to be able to provide various particle sizes, to be easy to clean, and to have a minimum...... of dead volume. The recovery of the sample when grinding as little as 50 mg of crude Cinchona bark was about 60%. Grinding is performed in seconds with no rise in temperature, and the grinder is easily disassembled to be cleaned. The influence of the particle size of the obtained powders on the recovery...

  7. An Efficient, Robust, and Inexpensive Grinding Device for Herbal Samples like Cinchona Bark.

    Science.gov (United States)

    Hansen, Steen Honoré; Holmfred, Else; Cornett, Claus; Maldonado, Carla; Rønsted, Nina

    2015-01-01

    An effective, robust, and inexpensive grinding device for the grinding of herb samples like bark and roots was developed by rebuilding a commercially available coffee grinder. The grinder was constructed to be able to provide various particle sizes, to be easy to clean, and to have a minimum of dead volume. The recovery of the sample when grinding as little as 50 mg of crude Cinchona bark was about 60%. Grinding is performed in seconds with no rise in temperature, and the grinder is easily disassembled to be cleaned. The influence of the particle size of the obtained powders on the recovery of analytes in extracts of Cinchona bark was investigated using HPLC.

  8. Real-Time and In-Flow Sensing Using a High Sensitivity Porous Silicon Microcavity-Based Sensor

    Directory of Open Access Journals (Sweden)

    Raffaele Caroselli

    2017-12-01

    Full Text Available Porous silicon seems to be an appropriate material platform for the development of high-sensitivity and low-cost optical sensors, as their porous nature increases the interaction with the target substances, and their fabrication process is very simple and inexpensive. In this paper, we present the experimental development of a porous silicon microcavity sensor and its use for real-time in-flow sensing application. A high-sensitivity configuration was designed and then fabricated, by electrochemically etching a silicon wafer. Refractive index sensing experiments were realized by flowing several dilutions with decreasing refractive indices, and measuring the spectral shift in real-time. The porous silicon microcavity sensor showed a very linear response over a wide refractive index range, with a sensitivity around 1000 nm/refractive index unit (RIU, which allowed us to directly detect refractive index variations in the 10−7 RIU range.

  9. Real-Time and In-Flow Sensing Using a High Sensitivity Porous Silicon Microcavity-Based Sensor.

    Science.gov (United States)

    Caroselli, Raffaele; Martín Sánchez, David; Ponce Alcántara, Salvador; Prats Quilez, Francisco; Torrijos Morán, Luis; García-Rupérez, Jaime

    2017-12-05

    Porous silicon seems to be an appropriate material platform for the development of high-sensitivity and low-cost optical sensors, as their porous nature increases the interaction with the target substances, and their fabrication process is very simple and inexpensive. In this paper, we present the experimental development of a porous silicon microcavity sensor and its use for real-time in-flow sensing application. A high-sensitivity configuration was designed and then fabricated, by electrochemically etching a silicon wafer. Refractive index sensing experiments were realized by flowing several dilutions with decreasing refractive indices, and measuring the spectral shift in real-time. The porous silicon microcavity sensor showed a very linear response over a wide refractive index range, with a sensitivity around 1000 nm/refractive index unit (RIU), which allowed us to directly detect refractive index variations in the 10 -7 RIU range.

  10. Energy Conversion Properties of ZnSiP2, a Lattice-Matched Material for Silicon-Based Tandem Photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, Aaron D.; Warren, Emily L.; Gorai, Prashun; Borup, Kasper A.; Krishna, Lakshmi; Kuciauskas, Darius; Dippo, Patricia C.; Ortiz, Brenden R.; Stradins, Paul; Stevanovic, Vladan; Toberer, Eric S.; Tamboli, Adele C.

    2016-11-21

    ZnSiP2 demonstrates promising potential as an optically active material on silicon. There has been a longstanding need for wide band gap materials that can be integrated with Si for tandem photovoltaics and other optoelectronic applications. ZnSiP2 is an inexpensive, earth abundant, wide band gap material that is stable and lattice matched with silicon. This conference proceeding summarizes our PV-relevant work on bulk single crystal ZnSiP2, highlighting the key findings and laying the ground work for integration into Si-based tandem devices.

  11. Simulation training for medical emergencies in the dental setting using an inexpensive software application.

    Science.gov (United States)

    Kishimoto, N; Mukai, N; Honda, Y; Hirata, Y; Tanaka, M; Momota, Y

    2017-11-09

    Every dental provider needs to be educated about medical emergencies to provide safe dental care. Simulation training is available with simulators such as advanced life support manikins and robot patients. However, the purchase and development costs of these simulators are high. We have developed a simulation training course on medical emergencies using an inexpensive software application. The purpose of this study was to evaluate the educational effectiveness of this course. Fifty-one dental providers participated in this study from December 2014 to March 2015. Medical simulation software was used to simulate a patient's vital signs. We evaluated participants' ability to diagnose and treat vasovagal syncope or anaphylaxis with an evaluation sheet and conducted a questionnaire before and after the scenario-based simulation training. The median evaluation sheet score for vasovagal syncope increased significantly from 7/9 before to 9/9 after simulation training. The median score for anaphylaxis also increased significantly from 8/12 to 12/12 (P simulation training. This simulation course improved participants' ability to diagnose and treat medical emergencies and improved their confidence. This course can be offered inexpensively using a software application. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  12. Earthworms Dilong: Ancient, Inexpensive, Noncontroversial Models May Help Clarify Approaches to Integrated Medicine Emphasizing Neuroimmune Systems

    Science.gov (United States)

    Cooper, Edwin L.; Balamurugan, Mariappan; Huang, Chih-Yang; Tsao, Clara R.; Heredia, Jesus; Tommaseo-Ponzetta, Mila; Paoletti, Maurizio G.

    2012-01-01

    Earthworms have provided ancient cultures with food and sources of medicinal cures. Ayurveda, traditional Chinese medicine (TCM), and practices in Japan, Vietnam, and Korea have focused first on earthworms as sources of food. Gradually fostering an approach to potential beneficial healing properties, there are renewed efforts through bioprospecting and evidence-based research to understand by means of rigorous investigations the mechanisms of action whether earthworms are used as food and/or as sources of potential medicinal products. Focusing on earthworms grew by serendipity from an extensive analysis of the earthworm's innate immune system. Their immune systems are replete with leukocytes and humoral products that exert credible health benefits. Their emerging functions with respect to evolution of innate immunity have long been superseded by their well-known ecological role in soil conservation. Earthworms as inexpensive, noncontroversial animal models (without ethical concerns) are not vectors of disease do not harbor parasites that threaten humans nor are they annoying pests. By recognizing their numerous ecological, environmental, and biomedical roles, substantiated by inexpensive and more comprehensive investigations, we will become more aware of their undiscovered beneficial properties. PMID:22888362

  13. Inexpensive Aerial Photogrammetry for Studies of Whales and Large Marine Animals

    Directory of Open Access Journals (Sweden)

    Stephen M. Dawson

    2017-11-01

    Full Text Available We describe a simple system enabling accurate measurement of swimming marine mammals and other large vertebrates from low-altitude single-frame photogrammetry via inexpensive modifications to a “prosumer” unmanned aerial vehicle (UAV equipped with gimballed micro4/3 camera and 25 mm lens. Image scale is established via an independently powered LIDAR/GPS data-logging system recording altitude and GPS location at 1 Hz. Photogrammetric calibration of the camera and lens allowed distortion parameters to be rigorously accounted for during image analysis, via a custom-programmed Graphical User Interface (GUI running in MATLAB. The datalogger, camera calibration methods and measurement software are adaptable to a wide range of UAV platforms. Mean LIDAR accuracy, measured from 10 bridges 9–39 m above water, was 99.9%. We conducted 136 flights in New Zealand's subantarctic Auckland Islands to measure southern right whales. Mean lengths of 10 individual whales, each photographed between 7 and 15 times, had CVs (SD/mean ranging from 0.5 to 1.8% (mean = 1.2%. Repeated measurements of a floating reference target showed a mean error of c.1%. Our system is relatively inexpensive, easily put together, produces accurate, repeatable measurements from single vertical images, and hence is applicable to a wide range of ecological questions in marine and terrestrial habitats.

  14. Vision and Control for UAVs: A Survey of General Methods andof Inexpensive Platforms for Infrastructure Inspection

    Directory of Open Access Journals (Sweden)

    Koppány Máthé

    2015-06-01

    Full Text Available Unmanned aerial vehicles (UAVs have gained significant attention in recent years. Low-cost platforms using inexpensive sensor payloads have been shown to provide satisfactory flight and navigation capabilities. In this report, we survey vision and control methods that can be applied to low-cost UAVs, and we list some popular inexpensive platforms and application fields where they are useful. We also highlight the sensor suites used where this information is available. We overview, among others, feature detection and tracking, optical flow and visual servoing, low-level stabilization and high-level planning methods. We then list popular low-cost UAVs, selecting mainly quadrotors. We discuss applications, restricting our focus to the field of infrastructure inspection. Finally, as an example, we formulate two use-cases for railway inspection, a less explored application field, and illustrate the usage of the vision and control techniques reviewed by selecting appropriate ones to tackle these use-cases. To select vision methods, we run a thorough set of experimental evaluations.

  15. Quantification of video-taped images in microcirculation research using inexpensive imaging software (Adobe Photoshop).

    Science.gov (United States)

    Brunner, J; Krummenauer, F; Lehr, H A

    2000-04-01

    Study end-points in microcirculation research are usually video-taped images rather than numeric computer print-outs. Analysis of these video-taped images for the quantification of microcirculatory parameters usually requires computer-based image analysis systems. Most software programs for image analysis are custom-made, expensive, and limited in their applicability to selected parameters and study end-points. We demonstrate herein that an inexpensive, commercially available computer software (Adobe Photoshop), run on a Macintosh G3 computer with inbuilt graphic capture board provides versatile, easy to use tools for the quantification of digitized video images. Using images obtained by intravital fluorescence microscopy from the pre- and postischemic muscle microcirculation in the skinfold chamber model in hamsters, Photoshop allows simple and rapid quantification (i) of microvessel diameters, (ii) of the functional capillary density and (iii) of postischemic leakage of FITC-labeled high molecular weight dextran from postcapillary venules. We present evidence of the technical accuracy of the software tools and of a high degree of interobserver reliability. Inexpensive commercially available imaging programs (i.e., Adobe Photoshop) provide versatile tools for image analysis with a wide range of potential applications in microcirculation research.

  16. Depth of interaction resolution measurements for a high resolution PET detector using position sensitive avalanche photodiodes

    International Nuclear Information System (INIS)

    Yang Yongfeng; Dokhale, Purushottam A; Silverman, Robert W; Shah, Kanai S; McClish, Mickel A; Farrell, Richard; Entine, Gerald; Cherry, Simon R

    2006-01-01

    We explore dual-ended read out of LSO arrays with two position sensitive avalanche photodiodes (PSAPDs) as a high resolution, high efficiency depth-encoding detector for PET applications. Flood histograms, energy resolution and depth of interaction (DOI) resolution were measured for unpolished LSO arrays with individual crystal sizes of 1.0, 1.3 and 1.5 mm, and for a polished LSO array with 1.3 mm pixels. The thickness of the crystal arrays was 20 mm. Good flood histograms were obtained for all four arrays, and crystals in all four arrays can be clearly resolved. Although the amplitude of each PSAPD signal decreases as the interaction depth moves further from the PSAPD, the sum of the two PSAPD signals is essentially constant with irradiation depth for all four arrays. The energy resolutions were similar for all four arrays, ranging from 14.7% to 15.4%. A DOI resolution of 3-4 mm (including the width of the irradiation band which is ∼2 mm) was obtained for all the unpolished arrays. The best DOI resolution was achieved with the unpolished 1 mm array (average 3.5 mm). The DOI resolution for the 1.3 mm and 1.5 mm unpolished arrays was 3.7 and 4.0 mm respectively. For the polished array, the DOI resolution was only 16.5 mm. Summing the DOI profiles across all crystals for the 1 mm array only degraded the DOI resolution from 3.5 mm to 3.9 mm, indicating that it may not be necessary to calibrate the DOI response separately for each crystal within an array. The DOI response of individual crystals in the array confirms this finding. These results provide a detailed characterization of the DOI response of these PSAPD-based PET detectors which will be important in the design and calibration of a PET scanner making use of this detector approach

  17. Performance improvement of silicon solar cells by nanoporous silicon coating

    Directory of Open Access Journals (Sweden)

    Dzhafarov T. D.

    2012-04-01

    Full Text Available In the present paper the method is shown to improve the photovoltaic parameters of screen-printed silicon solar cells by nanoporous silicon film formation on the frontal surface of the cell using the electrochemical etching. The possible mechanisms responsible for observed improvement of silicon solar cell performance are discussed.

  18. Neuromorphic Silicon Neuron Circuits

    Science.gov (United States)

    Indiveri, Giacomo; Linares-Barranco, Bernabé; Hamilton, Tara Julia; van Schaik, André; Etienne-Cummings, Ralph; Delbruck, Tobi; Liu, Shih-Chii; Dudek, Piotr; Häfliger, Philipp; Renaud, Sylvie; Schemmel, Johannes; Cauwenberghs, Gert; Arthur, John; Hynna, Kai; Folowosele, Fopefolu; Saighi, Sylvain; Serrano-Gotarredona, Teresa; Wijekoon, Jayawan; Wang, Yingxue; Boahen, Kwabena

    2011-01-01

    Hardware implementations of spiking neurons can be extremely useful for a large variety of applications, ranging from high-speed modeling of large-scale neural systems to real-time behaving systems, to bidirectional brain–machine interfaces. The specific circuit solutions used to implement silicon neurons depend on the application requirements. In this paper we describe the most common building blocks and techniques used to implement these circuits, and present an overview of a wide range of neuromorphic silicon neurons, which implement different computational models, ranging from biophysically realistic and conductance-based Hodgkin–Huxley models to bi-dimensional generalized adaptive integrate and fire models. We compare the different design methodologies used for each silicon neuron design described, and demonstrate their features with experimental results, measured from a wide range of fabricated VLSI chips. PMID:21747754

  19. Silicon containing copolymers

    CERN Document Server

    Amiri, Sahar; Amiri, Sanam

    2014-01-01

    Silicones have unique properties including thermal oxidative stability, low temperature flow, high compressibility, low surface tension, hydrophobicity and electric properties. These special properties have encouraged the exploration of alternative synthetic routes of well defined controlled microstructures of silicone copolymers, the subject of this Springer Brief. The authors explore the synthesis and characterization of notable block copolymers. Recent advances in controlled radical polymerization techniques leading to the facile synthesis of well-defined silicon based thermo reversible block copolymers?are described along with atom transfer radical polymerization (ATRP), a technique utilized to develop well-defined functional thermo reversible block copolymers. The brief also focuses on Polyrotaxanes and their great potential as stimulus-responsive materials which produce poly (dimethyl siloxane) (PDMS) based thermo reversible block copolymers.

  20. Neuromorphic silicon neuron circuits

    Directory of Open Access Journals (Sweden)

    Giacomo eIndiveri

    2011-05-01

    Full Text Available Hardware implementations of spiking neurons can be extremely useful for a large variety of applications, ranging from high-speed modeling of large-scale neural systems to real-time behaving systems, to bidirectional brain-machine interfaces. The specific circuit solutions used to implement silicon neurons depend on the application requirements. In this paper we describe the most common building blocks and techniques used to implement these circuits, and present an overview of a wide range of neuromorphic silicon neurons, which implement different computational models, ranging from biophysically realistic and conductance based Hodgkin-Huxley models to bi-dimensional generalized adaptive Integrate and Fire models. We compare the different design methodologies used for each silicon neuron design described, and demonstrate their features with experimental results, measured from a wide range of fabricated VLSI chips.

  1. Floating Silicon Method

    Energy Technology Data Exchange (ETDEWEB)

    Kellerman, Peter

    2013-12-21

    The Floating Silicon Method (FSM) project at Applied Materials (formerly Varian Semiconductor Equipment Associates), has been funded, in part, by the DOE under a “Photovoltaic Supply Chain and Cross Cutting Technologies” grant (number DE-EE0000595) for the past four years. The original intent of the project was to develop the FSM process from concept to a commercially viable tool. This new manufacturing equipment would support the photovoltaic industry in following ways: eliminate kerf losses and the consumable costs associated with wafer sawing, allow optimal photovoltaic efficiency by producing high-quality silicon sheets, reduce the cost of assembling photovoltaic modules by creating large-area silicon cells which are free of micro-cracks, and would be a drop-in replacement in existing high efficiency cell production process thereby allowing rapid fan-out into the industry.

  2. The LHCb Silicon Tracker

    Energy Technology Data Exchange (ETDEWEB)

    Tobin, Mark, E-mail: Mark.Tobin@epfl.ch

    2016-09-21

    The LHCb experiment is dedicated to the study of heavy flavour physics at the Large Hadron Collider (LHC). The primary goal of the experiment is to search for indirect evidence of new physics via measurements of CP violation and rare decays of beauty and charm hadrons. The LHCb detector has a large-area silicon micro-strip detector located upstream of a dipole magnet, and three tracking stations with silicon micro-strip detectors in the innermost region downstream of the magnet. These two sub-detectors form the LHCb Silicon Tracker (ST). This paper gives an overview of the performance and operation of the ST during LHC Run 1. Measurements of the observed radiation damage are shown and compared to the expectation from simulation.

  3. Removal of inclusions from silicon

    Science.gov (United States)

    Ciftja, Arjan; Engh, Thorvald Abel; Tangstad, Merete; Kvithyld, Anne; Øvrelid, Eivind Johannes

    2009-11-01

    The removal of inclusions from molten silicon is necessary to satisfy the purity requirements for solar grade silicon. This paper summarizes two methods that are investigated: (i) settling of the inclusions followed by subsequent directional solidification and (infiltration by ceramic foam filters. Settling of inclusions followed by directional solidification is of industrial importance for production of low-cost solar grade silicon. Filtration is reported as the most efficient method for removal of inclusions from the top-cut silicon scrap.

  4. Silicon photonic integration in telecommunications

    Directory of Open Access Journals (Sweden)

    Christopher Richard Doerr

    2015-08-01

    Full Text Available Silicon photonics is the guiding of light in a planar arrangement of silicon-based materials to perform various functions. We focus here on the use of silicon photonics to create transmitters and receivers for fiber-optic telecommunications. As the need to squeeze more transmission into a given bandwidth, a given footprint, and a given cost increases, silicon photonics makes more and more economic sense.

  5. Silicon Tracking Upgrade at CDF

    International Nuclear Information System (INIS)

    Kruse, M.C.

    1998-04-01

    The Collider Detector at Fermilab (CDF) is scheduled to begin recording data from Run II of the Fermilab Tevatron in early 2000. The silicon tracking upgrade constitutes both the upgrade to the CDF silicon vertex detector (SVX II) and the new Intermediate Silicon Layers (ISL) located at radii just beyond the SVX II. Here we review the design and prototyping of all aspects of these detectors including mechanical design, data acquisition, and a trigger based on silicon tracking

  6. Silicon microphones - a Danish perspective

    DEFF Research Database (Denmark)

    Bouwstra, Siebe; Storgaard-Larsen, Torben; Scheeper, Patrick

    1998-01-01

    Two application areas of microphones are discussed, those for precision measurement and those for hearing instruments. Silicon microphones are under investigation for both areas, and Danish industry plays a key role in both. The opportunities of silicon, as well as the challenges and expectations......, are discussed. For precision measurement the challenge for silicon is large, while for hearing instruments silicon seems to be very promising....

  7. Angle-resolved diffraction grating biosensor based on porous silicon

    Energy Technology Data Exchange (ETDEWEB)

    Lv, Changwu; Li, Peng [School of Physical Science and Technology, Xinjiang University, Urumqi 830046 (China); Jia, Zhenhong, E-mail: jzhh@xju.edu.cn; Liu, Yajun; Mo, Jiaqing; Lv, Xiaoyi [College of Information Science and Engineering, Xinjiang University, Urumqi 830046 (China)

    2016-03-07

    In this study, an optical biosensor based on a porous silicon composite structure was fabricated using a simple method. This structure consists of a thin, porous silicon surface diffraction grating and a one-dimensional porous silicon photonic crystal. An angle-resolved diffraction efficiency spectrum was obtained by measuring the diffraction efficiency at a range of incident angles. The angle-resolved diffraction efficiency of the 2nd and 3rd orders was studied experimentally and theoretically. The device was sensitive to the change of refractive index in the presence of a biomolecule indicated by the shift of the diffraction efficiency spectrum. The sensitivity of this sensor was investigated through use of an 8 base pair antifreeze protein DNA hybridization. The shifts of the angle-resolved diffraction efficiency spectrum showed a relationship with the change of the refractive index, and the detection limit of the biosensor reached 41.7 nM. This optical device is highly sensitive, inexpensive, and simple to fabricate. Using shifts in diffraction efficiency spectrum to detect biological molecules has not yet been explored, so this study establishes a foundation for future work.

  8. CMS silicon tracker developments

    International Nuclear Information System (INIS)

    Civinini, C.; Albergo, S.; Angarano, M.; Azzi, P.; Babucci, E.; Bacchetta, N.; Bader, A.; Bagliesi, G.; Basti, A.; Biggeri, U.; Bilei, G.M.; Bisello, D.; Boemi, D.; Bosi, F.; Borrello, L.; Bozzi, C.; Braibant, S.; Breuker, H.; Bruzzi, M.; Buffini, A.; Busoni, S.; Candelori, A.; Caner, A.; Castaldi, R.; Castro, A.; Catacchini, E.; Checcucci, B.; Ciampolini, P.; Creanza, D.; D'Alessandro, R.; Da Rold, M.; Demaria, N.; De Palma, M.; Dell'Orso, R.; Della Marina, R.D.R.; Dutta, S.; Eklund, C.; Feld, L.; Fiore, L.; Focardi, E.; French, M.; Freudenreich, K.; Frey, A.; Fuertjes, A.; Giassi, A.; Giorgi, M.; Giraldo, A.; Glessing, B.; Gu, W.H.; Hall, G.; Hammarstrom, R.; Hebbeker, T.; Honma, A.; Hrubec, J.; Huhtinen, M.; Kaminsky, A.; Karimaki, V.; Koenig, St.; Krammer, M.; Lariccia, P.; Lenzi, M.; Loreti, M.; Luebelsmeyer, K.; Lustermann, W.; Maettig, P.; Maggi, G.; Mannelli, M.; Mantovani, G.; Marchioro, A.; Mariotti, C.; Martignon, G.; Evoy, B. Mc; Meschini, M.; Messineo, A.; Migliore, E.; My, S.; Paccagnella, A.; Palla, F.; Pandoulas, D.; Papi, A.; Parrini, G.; Passeri, D.; Pieri, M.; Piperov, S.; Potenza, R.; Radicci, V.; Raffaelli, F.; Raymond, M.; Santocchia, A.; Schmitt, B.; Selvaggi, G.; Servoli, L.; Sguazzoni, G.; Siedling, R.; Silvestris, L.; Starodumov, A.; Stavitski, I.; Stefanini, G.; Surrow, B.; Tempesta, P.; Tonelli, G.; Tricomi, A.; Tuuva, T.; Vannini, C.; Verdini, P.G.; Viertel, G.; Xie, Z.; Yahong, Li; Watts, S.; Wittmer, B.

    2002-01-01

    The CMS Silicon tracker consists of 70 m 2 of microstrip sensors which design will be finalized at the end of 1999 on the basis of systematic studies of device characteristics as function of the most important parameters. A fundamental constraint comes from the fact that the detector has to be operated in a very hostile radiation environment with full efficiency. We present an overview of the current results and prospects for converging on a final set of parameters for the silicon tracker sensors

  9. Silicon hybrid integration

    International Nuclear Information System (INIS)

    Li Xianyao; Yuan Taonu; Shao Shiqian; Shi Zujun; Wang Yi; Yu Yude; Yu Jinzhong

    2011-01-01

    Recently,much attention has concentrated on silicon based photonic integrated circuits (PICs), which provide a cost-effective solution for high speed, wide bandwidth optical interconnection and optical communication.To integrate III-V compounds and germanium semiconductors on silicon substrates,at present there are two kinds of manufacturing methods, i.e., heteroepitaxy and bonding. Low-temperature wafer bonding which can overcome the high growth temperature, lattice mismatch,and incompatibility of thermal expansion coefficients during heteroepitaxy, has offered the possibility for large-scale heterogeneous integration. In this paper, several commonly used bonding methods are reviewed, and the future trends of low temperature wafer bonding envisaged. (authors)

  10. Strained Silicon Photonics

    Directory of Open Access Journals (Sweden)

    Ralf B. Wehrspohn

    2012-05-01

    Full Text Available A review of recent progress in the field of strained silicon photonics is presented. The application of strain to waveguide and photonic crystal structures can be used to alter the linear and nonlinear optical properties of these devices. Here, methods for the fabrication of strained devices are summarized and recent examples of linear and nonlinear optical devices are discussed. Furthermore, the relation between strain and the enhancement of the second order nonlinear susceptibility is investigated, which may enable the construction of optically active photonic devices made of silicon.

  11. A novel type heterojunction photodiodes formed junctions of Au/LiZnSnO and LiZnSnO/p-Si in series

    Energy Technology Data Exchange (ETDEWEB)

    Aydin, H. [Department of Metallurgical and Materials Science, Faculty of Engineering, Tunceli University, Tunceli (Turkey); Tataroğlu, A. [Department of Physics, Faculty of Science, Gazi University, Ankara (Turkey); Al-Ghamdi, Ahmed A. [Department of Physics, Faculty of Science, King Abdulaziz University, Jeddah (Saudi Arabia); Yakuphanoglu, F., E-mail: fyhanoglu@firat.edu.tr [Department of Metallurgical and Materials Science, Faculty of Engineering, Tunceli University, Tunceli (Turkey); Department of Physics, Faculty of Science, King Abdulaziz University, Jeddah (Saudi Arabia); El-Tantawy, Farid [Department of Physics, Faculty of Science, Suez Canal University, Ismailia (Egypt); Farooq, W.A. [Physics and Astronomy Department, College of Science, King Saud University, Riyadh (Saudi Arabia)

    2015-03-15

    Highlights: • Lithium–zinc–tin–oxide thin films were prepared by sol gel method. • The Au/LiZnSnO/p-Si/Al photodiodes were fabricated using a LZTO layer grown on p-Si. • The photodiodes with Li-doped ZTO interfacial layer exhibited a better device performance. - Abstract: Lithium–zinc–tin–oxide thin films were prepared by sol gel method. The structural and optical properties of the films were investigated. The optical band gaps of the LiZnSnO films were found to be 3.78 eV for 0 at.% Li, 3.77 eV for 1 at.% Li, 3.87 eV for 3 at.% Li and 3.85 eV for 5 at.% Li, respectively. Au/LiZnSnO/p-Si/Al photodiodes were fabricated using a lithium–zinc–tin–oxide (LZTO, Li–Zn–Sn–O) layer grown on p-Si semiconductor. The electrical characteristics of the photodiodes were analyzed by current–voltage, capacitance–voltage and conductance–voltage measurements. The reverse current of the diodes increases with both the increasing illumination intensity and Li content. It was found that the Li-doped ZTO photodiodes exhibited a better device performance than those with an undoped ZTO.

  12. Elite silicon and solar power

    International Nuclear Information System (INIS)

    Yasamanov, N.A.

    2000-01-01

    The article is of popular character, the following issues being considered: conversion of solar energy into electric one, solar batteries in space and on the Earth, growing of silicon large-size crystals, source material problems relating to silicon monocrystals production, outlooks of solar silicon batteries production [ru

  13. The photovoltaic impact of atomic layer deposited TiO2 interfacial layer on Si-based photodiodes

    Science.gov (United States)

    Karabulut, Abdulkerim; Orak, İkram; Türüt, Abdulmecit

    2018-06-01

    In present work, photocurrent, current-voltage (I-V) and capacitance/conductance-voltage-frequency (C/G-V-f) measurements were analyzed for the photodiode and diode parameters of Al/TiO2/p-Si structure. The TiO2 thin film structure was deposited on p-Si by using atomic layer deposition technique (ALD) and its thickness was about 10 nm. The surface morphology of TiO2 coated on p-Si structure was observed via atomic force microscope (AFM). Barrier height (Φb) and ideality factor (n) values of device were found to be 0.80 eV, 0.70 eV, 0.56 eV and 1.04, 2.24, 10.27 under dark, 10 and 100 mW/cm2, respectively. Some photodiodes parameters such as fill factor (FF), power efficiency (%η), open circuit voltage (Voc), short circuit current (Isc) were obtained from I-V measurement under different light intensity. FF and η were accounted 49.2, 39,0 and 0.05, 0.45 under 10 and 100 mW/cm2 light power intensity, respectively. C-2-V graph was plotted from C-V-f measurements and zero bias voltage (V0), donor concentration (Nd), Fermi energy (EF), barrier height (Φb) and maximum electric field (Em) were determined from C-2-V data for different frequencies. The electrical and photocurrent values demonstrated that it can be used for photodiode, photo detector and photo sensing applications.

  14. Nanosized graphene sheets enhanced photoelectric behavior of carbon film on p-silicon substrate

    Science.gov (United States)

    Yang, Lei; Hu, Gaijuan; Zhang, Dongqing; Diao, Dongfeng

    2016-07-01

    We found that nanosized graphene sheets enhanced the photoelectric behavior of graphene sheets embedded carbon (GSEC) film on p-silicon substrate, which was deposited under low energy electron irradiation in electron cyclotron resonance plasma. The GSEC/p-Si photodiode exhibited good photoelectric performance with photoresponsivity of 206 mA/W, rise and fall time of 2.2, and 4.3 μs for near-infrared (850 nm) light. The origin of the strong photoelectric behavior of GSEC film was ascribed to the appearance of graphene nanosheets, which led to higher barrier height and photoexcited electron-collection efficiency. This finding indicates that GSEC film has the potential for photoelectric applications.

  15. Nanosized graphene sheets enhanced photoelectric behavior of carbon film on p-silicon substrate

    International Nuclear Information System (INIS)

    Yang, Lei; Hu, Gaijuan; Zhang, Dongqing; Diao, Dongfeng

    2016-01-01

    We found that nanosized graphene sheets enhanced the photoelectric behavior of graphene sheets embedded carbon (GSEC) film on p-silicon substrate, which was deposited under low energy electron irradiation in electron cyclotron resonance plasma. The GSEC/p-Si photodiode exhibited good photoelectric performance with photoresponsivity of 206 mA/W, rise and fall time of 2.2, and 4.3 μs for near-infrared (850 nm) light. The origin of the strong photoelectric behavior of GSEC film was ascribed to the appearance of graphene nanosheets, which led to higher barrier height and photoexcited electron-collection efficiency. This finding indicates that GSEC film has the potential for photoelectric applications.

  16. Nanosized graphene sheets enhanced photoelectric behavior of carbon film on p-silicon substrate

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Lei; Hu, Gaijuan; Zhang, Dongqing [Key Laboratory of Education Ministry for Modern Design and Rotor-Bearing System, School of Mechanical Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); Diao, Dongfeng, E-mail: dfdiao@szu.edu.cn [Institute of Nanosurface Science and Engineering (INSE), Shenzhen University, Shenzhen 518060 (China)

    2016-07-18

    We found that nanosized graphene sheets enhanced the photoelectric behavior of graphene sheets embedded carbon (GSEC) film on p-silicon substrate, which was deposited under low energy electron irradiation in electron cyclotron resonance plasma. The GSEC/p-Si photodiode exhibited good photoelectric performance with photoresponsivity of 206 mA/W, rise and fall time of 2.2, and 4.3 μs for near-infrared (850 nm) light. The origin of the strong photoelectric behavior of GSEC film was ascribed to the appearance of graphene nanosheets, which led to higher barrier height and photoexcited electron-collection efficiency. This finding indicates that GSEC film has the potential for photoelectric applications.

  17. Study of the photo-detection efficiency of FBK High-Density silicon photomultipliers

    International Nuclear Information System (INIS)

    Zappalà, G.; Regazzoni, V.; Acerbi, F.; Ferri, A.; Gola, A.; Paternoster, G.; Zorzi, N.; Piemonte, C.

    2016-01-01

    This work presents a study of the factors contributing to the Photo-Detection Efficiency of Silicon Photomultipliers (SiPMs): Quantum Efficiency, Triggering Probability and Fill Factor. Two different SiPM High-Density technologies are tested, NUV-HD, based on n-on-p junction, and RGB-HD, based on p-on-n junction, developed at FBK, Trento. The quantum efficiency was measured on photodiodes produced along with the SiPMs. The triggering probability, as a function of wavelength and bias voltage, was measured on circular Single Photon Avalanche Diodes (SPADs) with 100% fill factor. Square SPADs, having the same layout of single SiPM cells, were studied to measure the effective fill factor and compare it to the nominal value. The comparison of the circular and square SPADs allows to get the transition region size between the effective active area of the cell and the one defined by the layout.

  18. Simulation and measurement of total ionizing dose radiation induced image lag increase in pinned photodiode CMOS image sensors

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jing [School of Materials Science and Engineering, Xiangtan University, Hunan (China); State Key Laboratory of Intense Pulsed Irradiation Simulation and Effect, Northwest Institute of Nuclear Technology, P.O.Box 69-10, Xi’an (China); Chen, Wei, E-mail: chenwei@nint.ac.cn [State Key Laboratory of Intense Pulsed Irradiation Simulation and Effect, Northwest Institute of Nuclear Technology, P.O.Box 69-10, Xi’an (China); Wang, Zujun, E-mail: wangzujun@nint.ac.cn [State Key Laboratory of Intense Pulsed Irradiation Simulation and Effect, Northwest Institute of Nuclear Technology, P.O.Box 69-10, Xi’an (China); Xue, Yuanyuan; Yao, Zhibin; He, Baoping; Ma, Wuying; Jin, Junshan; Sheng, Jiangkun; Dong, Guantao [State Key Laboratory of Intense Pulsed Irradiation Simulation and Effect, Northwest Institute of Nuclear Technology, P.O.Box 69-10, Xi’an (China)

    2017-06-01

    This paper presents an investigation of total ionizing dose (TID) induced image lag sources in pinned photodiodes (PPD) CMOS image sensors based on radiation experiments and TCAD simulation. The radiation experiments have been carried out at the Cobalt −60 gamma-ray source. The experimental results show the image lag degradation is more and more serious with increasing TID. Combining with the TCAD simulation results, we can confirm that the junction of PPD and transfer gate (TG) is an important region forming image lag during irradiation. These simulations demonstrate that TID can generate a potential pocket leading to incomplete transfer.

  19. Evaluation of a fast single-photon avalanche photodiode for measurement of early transmitted photons through diffusive media.

    Science.gov (United States)

    Mu, Ying; Valim, Niksa; Niedre, Mark

    2013-06-15

    We tested the performance of a fast single-photon avalanche photodiode (SPAD) in measurement of early transmitted photons through diffusive media. In combination with a femtosecond titanium:sapphire laser, the overall instrument temporal response time was 59 ps. Using two experimental models, we showed that the SPAD allowed measurement of photon-density sensitivity functions that were approximately 65% narrower than the ungated continuous wave case at very early times. This exceeds the performance that we have previously achieved with photomultiplier-tube-based systems and approaches the theoretical maximum predicted by time-resolved Monte Carlo simulations.

  20. A novel camera type for very high energy gamma-ray astronomy based on Geiger-mode avalanche photodiodes

    International Nuclear Information System (INIS)

    Anderhub, H; Biland, A; Boller, A; Braun, I; Commichau, S; Commichau, V; Dorner, D; Gendotti, A; Grimm, O; Gunten, H von; Hildebrand, D; Horisberger, U; Kraehenbuehl, T; Kranich, D; Lorenz, E; Lustermann, W; Backes, M; Neise, D; Bretz, T; Mannheim, K

    2009-01-01

    Geiger-mode avalanche photodiodes (G-APD) are promising new sensors for light detection in atmospheric Cherenkov telescopes. In this paper, the design and commissioning of a 36-pixel G-APD prototype camera is presented. The data acquisition is based on the Domino Ring Sampling (DRS2) chip. A sub-nanosecond time resolution has been achieved. Cosmic-ray induced air showers have been recorded using an imaging mirror setup, in a self-triggered mode. This is the first time that such measurements have been carried out with a complete G-APD camera.