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Sample records for silicon pin photodiodes

  1. Fast neutron damage of silicon pin photodiodes

    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)

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

    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

  3. Radon measurements with a PIN photodiode

    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

  4. Panoramic irradiator dose mapping with pin photodiodes

    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)

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

    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

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

    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.

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

    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

  8. 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

    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

  9. 75 MeV boron ion irradiation studies on Si PIN photodiodes

    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.

  10. Alpha particles spectrometer with photodiode PIN

    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)

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

    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

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

    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.

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

    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

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

    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

  15. A radiation detector fabricated from silicon photodiode.

    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.

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

    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.

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

    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.

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

    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.

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

    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.

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

    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.

  1. Alpha particles spectrometer with photodiode PIN; Espectrometro de particulas alfa con fotodiodo PIN

    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)

  2. Low Cost silicon photodiodes for alpha spectrometry

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

    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.

  4. Properties of the photodiode PiN as neutron detector

    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.)

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

    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.

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

    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 ...

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

    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.

  8. 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

    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.

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

    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

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

    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.

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

    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

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

    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.

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

    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

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

    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%.

  15. Performance Analysis of OCDMA Based on AND Detection in FTTH Access Network Using PIN & APD Photodiodes

    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.

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

    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.

  17. Identification of radiation induced dark current sources in pinned photodiode CMOS image sensors

    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)

  18. Characterization of total ionizing dose damage in COTS pinned photodiode CMOS image sensors

    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.

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

    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

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

    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...

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

    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.

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

    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.

  3. An iterative method applied to optimize the design of PIN photodiodes for enhanced radiation tolerance and maximum light response

    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.

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

    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)

  5. Leakage current of amorphous silicon p-i-n diodes made by ion shower doping

    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

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

    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)

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

    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.

  8. Simulation and measurement of total ionizing dose radiation induced image lag increase in pinned photodiode CMOS image sensors

    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.

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

    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

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

    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.)

  11. Simulation for spectral response of solar-blind AlGaN based p-i-n photodiodes

    Xue, Shiwei; Xu, Jintong; Li, Xiangyang

    2015-04-01

    In this article, we introduced how to build a physical model of refer to the device structure and parameters. Simulations for solar-blind AlGaN based p-i-n photodiodes spectral characteristics were conducted in use of Silvaco TCAD, where device structure and parameters are comprehensively considered. In simulation, the effects of polarization, Urbach tail, mobility, saturated velocities and lifetime in AlGaN device was considered. Especially, we focused on how the concentration-dependent Shockley-Read-Hall (SRH) recombination model affects simulation results. By simulating, we analyzed the effects in spectral response caused by TAUN0 and TAUP0, and got the values of TAUN0 and TAUP0 which can bring a result coincides with test results. After that, we changed their values and made the simulation results especially the part under 255 nm performed better. In conclusion, the spectral response between 200 nm and 320 nm of solar-blind AlGaN based p-i-n photodiodes were simulated and compared with test results. We also found that TAUN0 and TAUP0 have a large impact on spectral response of AlGaN material.

  12. Silicide Schottky Contacts to Silicon: Screened Pinning at Defect Levels

    Drummond, T.J.

    1999-03-11

    Silicide Schottky contacts can be as large as 0.955 eV (E{sub v} + 0.165 eV) on n-type silicon and as large as 1.05 eV (E{sub c} {minus} 0.07 eV) on p-type silicon. Current models of Schottky barrier formation do not provide a satisfactory explanation of occurrence of this wide variation. A model for understanding Schottky contacts via screened pinning at defect levels is presented. In the present paper it is shown that most transition metal silicides are pinned approximately 0.48 eV above the valence band by interstitial Si clusters. Rare earth disilicides pin close to the divacancy acceptor level 0.41 eV below the conduction band edge while high work function silicides of Ir and Pt pin close to the divacancy donor level 0.21 eV above the valence band edge. Selection of a particular defect pinning level depends strongly on the relative positions of the silicide work function and the defect energy level on an absolute energy scale.

  13. Application of a radiation detector in the interdisciplinary study. 1. Portable fluorescent X-ray analysis using the Si-PIN photodiode

    Ito, Yutaka

    2000-01-01

    As a semiconductor used for X-ray detector has excellent resolution, it must be cooled by liquid nitrogen at its use, which is a limitation on its actual use and applications. Then, a compound detector with wider bandwidth such as CdTe and HgI 2 has conventionally been used to attempt to use the detector at room temperature. Here was adopted an Si-PIN photodiode for a representative small type semiconductor detector unnecessary for liquid nitrogen, to introduce small and portable fluorescent X-ray analyzer for its application. As Si-PIN can work at room temperature, it has large leak current and insufficiently spread empty phase, so it is used by cooling due to Peltier element and so on. Then, here was used an X-ray detector, XR-100CR of AMPTEK Inc. composed of Si-PIN photodiode and a Pre-AMP. And, for a portable fluorescent X-ray analyzer, the Si-PIN photodiode detector of AMPTEK Inc., and a closely sealed small radiation source of 50 μ Ci 241 Am for excitation of X-ray in specimen were used. Its working principle consists of excitation of elements in a specimen with X- and gamma-ray from 241 Am, and detection of emitted fluorescent X-ray with Si-PIN photodiode. (G.K.)

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

    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

  15. Influence of transfer gate design and bias on the radiation hardness of pinned photodiode CMOS image sensors

    Goiffon, V.; Estribeau, M.; Cervantes, P.; Molina, R.; Magnan, P.; Gaillardin, M.

    2014-01-01

    The effects of Cobalt 60 gamma-ray irradiation on pinned photodiode (PPD) CMOS image sensors (CIS) are investigated by comparing the total ionizing dose (TID) response of several transfer gate (TG) and PPD designs manufactured using a 180 nm CIS process. The TID induced variations of charge transfer efficiency (CTE), pinning voltage, equilibrium full well capacity (EFWC), full well capacity (FWC) and dark current measured on the different pixel designs lead to the conclusion that only three degradation sources are responsible for all the observed radiation effects: the pre-metal dielectric (PMD) positive trapped charge, the TG sidewall spacer positive trapped charge and, with less influence, the TG channel shallow trench isolation (STI) trapped charge. The different FWC evolutions with TID presented here are in very good agreement with a recently proposed analytical model. This work also demonstrates that the peripheral STI is not responsible for the observed degradations and thus that the enclosed layout TG design does not improve the radiation hardness of PPD CIS. The results of this study also lead to the conclusion that the TG OFF voltage bias during irradiation has no influence on the radiation effects. Alternative design and process solutions to improve the radiation hardness of PPD CIS are discussed. (authors)

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

    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.

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

    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.

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

    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.

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

    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.

  20. Photoelectric characteristics of an inverse U-shape buried doping design for crosstalk suppression in pinned photodiodes

    Cao Chen; Zhang Bing; Li Xin; Wu Longsheng; Wang Junfeng

    2014-01-01

    A design of an inverse U-shape buried doping in a pinned photodiode (PPD) of CMOS image sensors is proposed for electrical crosstalk suppression between adjacent pixels. The architecture achieves no extra fill factor consumption, and proper built-in electric fields can be established according to the doping gradient created by the injections of the extremely low P-type doping buried regions in the epitaxial layer, causing the excess electrons to easily drift back to the photosensitive area rarely with a diffusion probability; the overall junction capacitance and photosensitive area extensions for a full well capacity (FWC) and internal quantum efficiency (IQE) improving are achieved by the injection of a buried N-type doping. By considering the image lag issue, the process parameters of all the injections have been precisely optimized. Optical simulation results based on the finite difference time domain method show that compared to the conventional PPD, the electrical crosstalk rate of the proposed architecture can be decreased by 60%–80% at an incident wavelength beyond 450 nm, IQE can be clearly improved at an incident wavelength between 400 and 600 nm, and the FWC can be enhanced by 107.5%. Furthermore, the image lag performance is sustained to a perfect low level. The present study provides important guidance on the design of ultra high resolution image sensors. (semiconductor devices)

  1. Waveguide-integrated vertical pin photodiodes of Ge fabricated on p+ and n+ Si-on-insulator layers

    Ito, Kazuki; Hiraki, Tatsurou; Tsuchizawa, Tai; Ishikawa, Yasuhiko

    2017-04-01

    Vertical pin structures of Ge photodiodes (PDs) integrated with Si optical waveguides are fabricated by depositing Ge epitaxial layers on Si-on-insulator (SOI) layers, and the performances of n+-Ge/i-Ge/p+-SOI PDs are compared with those of p+-Ge/i-Ge/n+-SOI PDs. Both types of PDs show responsivities as high as 1.0 A/W at 1.55 µm, while the dark leakage current is different, which is consistent with previous reports on free-space PDs formed on bulk Si wafers. The dark current of the p+-Ge/i-Ge/n+-SOI PDs is higher by more than one order of magnitude. Taking into account the activation energies for dark current as well as the dependence on PD area, the dark current of the n+-Ge/i-Ge/p+-SOI PDs is dominated by the thermal generation of carriers via mid-gap defect levels in Ge, while for the p+-Ge/i-Ge/n+-SOI PDs, the dark current is ascribed to not only thermal generation but also other mechanisms such as locally formed conduction paths.

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

    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.)

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

    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.

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

    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

  5. Temperature dependent characterization of gallium arsenide X-ray mesa p-i-n photodiodes

    Lioliou, G., E-mail: G.Lioliou@sussex.ac.uk; Barnett, A. M. [Semiconductor Materials and Devices Laboratory, Department Engineering and Design, School of Engineering and Informatics, University of Sussex, Falmer, Brighton BN1 9QT (United Kingdom); Meng, X.; Ng, J. S. [Department of Electronic and Electrical Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD (United Kingdom)

    2016-03-28

    Electrical characterization of two GaAs p{sup +}-i-n{sup +} mesa X-ray photodiodes over the temperature range 0 °C to 120 °C together with characterization of one of the diodes as an X-ray detector over the temperature range 0 °C to 60 °C is reported as part of the development of photon counting X-ray spectroscopic systems for harsh environments. The randomly selected diodes were fully etched and unpassivated. The diodes were 200 μm in diameter and had 7 μm thick i layers. The leakage current density was found to increase from (3 ± 1) nA/cm{sup −2} at 0 °C to (24.36 ± 0.05) μA/cm{sup −2} at 120 °C for D1 and from a current density smaller than the uncertainty (0.2 ± 1.2) nA/cm{sup −2} at 0 °C to (9.39 ± 0.02) μA/cm{sup −2} at 120 °C for D2 at the maximum investigated reverse bias (15 V). The best energy resolution (FWHM at 5.9 keV) was achieved at 5 V reverse bias, at each temperature; 730 eV at 0 °C, 750 eV at 20 °C, 770 eV at 40 °C, and 840 eV at 60 °C. It was found that the parallel white noise was the main source of the photopeak broadening only when the detector operated at 60 °C, at 5 V, 10 V, and 15 V reverse bias and at long shaping times (>5 μs), whereas the sum of the dielectric noise and charge trapping noise was the dominant source of noise for all the other spectra.

  6. Testing of the KRI-developed Silicon PIN Radioxenon Detector

    Foxe, Michael P.; McIntyre, Justin I.

    2015-01-01

    Radioxenon detectors are used for the verification of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) in a network of detectors throughout the world called the International Monitoring System (IMS). The Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) Provisional Technical Secretariat (PTS) has tasked Pacific Northwest National Laboratory (PNNL) with testing a V.G. Khlopin Radium Institute (KRI) and Lares Ltd-developed Silicon PIN detector for radioxenon detection. PNNL measured radioxenon with the silicon PIN detector and determined its potential compared to current plastic scintillator beta cells. While the PNNL tested Si detector experienced noise issues, a second detector was tested in Russia at Lares Ltd, which did not exhibit the noise issues. Without the noise issues, the Si detector produces much better energy resolution and isomer peak separation than a conventional plastic scintillator cell used in the SAUNA systems in the IMS. Under the assumption of 1 cm 3 of Xe in laboratory-like conditions, 24-hr count time (12-hr count time for the SAUNA), with the respective shielding the minimum detectable concentrations for the Si detector tested by Lares Ltd (and a conventional SAUNA system) were calculated to be: 131m Xe - 0.12 mBq/m 3 (0.12 mBq/m 3 ); 133 Xe - 0.18 mBq/m 3 (0.21 mBq/m 3 ); 133m Xe - 0.07 mBq/m 3 (0.15 mBq/m 3 ); 135 Xe - 0.45 mBq/m 3 (0.67 mBq/m 3 ). Detection limits, which are one of the important factors in choosing the best detection technique for radioxenon in field conditions, are significantly better than for SAUNA-like detection systems for 131m Xe and 133m Xe, but similar for 133 Xe and 135 Xe. Another important factor is the amount of ''memory effect'' or carry over signal from one radioxenon measurement to the subsequent sample. The memory effect is reduced by a factor of 10 in the Si PIN detector compared to the current plastic scintillator cells. There is potential for further reduction with the

  7. A compact 16-module camera using 64-pixel CsI(Tl)/Si p-i-n photodiode imaging modules

    Choong, W.-S.; Gruber, G. J.; Moses, W. W.; Derenzo, S. E.; Holland, S. E.; Pedrali-Noy, M.; Krieger, B.; Mandelli, E.; Meddeler, G.; Wang, N. W.; Witt, E. K.

    2002-10-01

    We present a compact, configurable scintillation camera employing a maximum of 16 individual 64-pixel imaging modules resulting in a 1024-pixel camera covering an area of 9.6 cm/spl times/9.6 cm. The 64-pixel imaging module consists of optically isolated 3 mm/spl times/3 mm/spl times/5 mm CsI(Tl) crystals coupled to a custom array of Si p-i-n photodiodes read out by a custom integrated circuit (IC). Each imaging module plugs into a readout motherboard that controls the modules and interfaces with a data acquisition card inside a computer. For a given event, the motherboard employs a custom winner-take-all IC to identify the module with the largest analog output and to enable the output address bits of the corresponding module's readout IC. These address bits identify the "winner" pixel within the "winner" module. The peak of the largest analog signal is found and held using a peak detect circuit, after which it is acquired by an analog-to-digital converter on the data acquisition card. The camera is currently operated with four imaging modules in order to characterize its performance. At room temperature, the camera demonstrates an average energy resolution of 13.4% full-width at half-maximum (FWHM) for the 140-keV emissions of /sup 99m/Tc. The system spatial resolution is measured using a capillary tube with an inner diameter of 0.7 mm and located 10 cm from the face of the collimator. Images of the line source in air exhibit average system spatial resolutions of 8.7- and 11.2-mm FWHM when using an all-purpose and high-sensitivity parallel hexagonal holes collimator, respectively. These values do not change significantly when an acrylic scattering block is placed between the line source and the camera.

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

    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

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

    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.

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

    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)

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

    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

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

    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.

  13. The silicon-silicon oxide multilayers utilization as intrinsic layer on pin solar cells

    Colder, H.; Marie, P.; Gourbilleau, F.

    2008-01-01

    Silicon nanostructures are promising candidate for the intrinsic layer on pin solar cells. In this work we report on new material: silicon-rich silicon oxide (SRSO) deposited by reactive magnetron sputtering of a pure silica target and an interesting structure: multilayers consisting of a stack of SRSO and pure silicon oxide layers. Two thicknesses of the SRSO sublayer, t SRSO , are studied 3 nm and 5 nm whereas the thickness of silica sublayer is maintaining at 3 nm. The presence of nanocrystallites of silicon, evidenced by X-Ray diffraction (XRD), leads to photoluminescence (PL) emission at room temperature due to the quantum confinement of the carriers. The PL peak shifts from 1.3 eV to 1.5 eV is correlated to the decreasing of t SRSO from 5 nm down to 3 nm. In the purpose of their potential utilization for i-layer, the optical properties are studied by absorption spectroscopy. The achievement a such structures at promising absorption properties. Moreover by favouring the carriers injection by the tunnel effect between silicon nanograins and silica sublayers, the multilayers seem to be interesting for solar cells

  14. Signal amplification and leakage current suppression in amorphous silicon p-i-n diodes by field profile tailoring

    Hong, W.S.; Zhong, F.; Mireshghi, A.; Perez-Mendez, V.

    1999-01-01

    The performance of amorphous silicon p-i-n diodes as radiation detectors in terms of signal amplitude can be greatly improved when there is a built-in signal gain mechanism. The authors describe an avalanche gain mechanism which is achieved by introducing stacked intrinsic, p-type, and n-type layers into the diode structure. They replaced the intrinsic layer of the conventional p-i-n diode with i 1 -p-i 2 -n-i 3 multilayers. The i 2 layer (typically 1 ∼ 3 microm) achieves an electric field > 10 6 V/cm, while maintaining the p-i interfaces to the metallic contact at electric fields 4 V/cm, when the diode is fully depleted. For use in photo-diode applications the whole structure is less than 10 microm thick. Avalanche gains of 10 ∼ 50 can be obtained when the diode is biased to ∼ 500 V. Also, dividing the electrodes to strips of 2 microm width and 20 microm pitch reduced the leakage current up to an order of magnitude, and increased light transmission without creating inactive regions

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

    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

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

    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. Gamma-ray vulnerability of light-emitting diodes injection-laser diodes and pin-photodiodes for 1.3 μm wavelength-fiber optics

    Breuze, G.; Serre, J.

    1992-01-01

    With the increasing use of optical data links, it becomes essential to test for radiation vulnerability not only the transmission support - fiber and cable - but also fiber-end electro-optical components that could be exposed to hostile environment. Presently there is a significant number of radiation tests of optical fibers [1,2,3[. Here are only given a few results obtained on gradient index multimode fibers with and without phosphor. These data provide an important contribution to the improvement of all standard electro-optical pigtailed components working on the 1.3 μm wavelength: light-emitting diodes (LED), injection-laser diode modules (LDM) and pin-photodiodes (PD). Multicomponent LDM behaviour under CO 60 exposure was extensively tested. Hardened optical data links allow now to ensure medium data transmission rates on appreciable fiber - lengths despite medium steady - state gamma-ray exposure

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

    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

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

    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)

  20. 2 μm wavelength range InP-based type-II quantum well photodiodes heterogeneously integrated on silicon photonic integrated circuits.

    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.

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

    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.

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

    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)

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

    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

  4. Advances in the project about Pin type silicon radiation detectors

    Ramirez F, J.; Cerdeira, A.; Aceves, M.; Diaz, A.; Estrada, M.; Rosales, P.; Cabal, A.E.; Montano L, M.; Leyva, A.

    1998-01-01

    The obtained advances in the collaboration project ININ-CINVESTAV about development of Pin type semiconductor radiation detectors here are presented. It has been characterized the response to different types of radiation made in CINVESTAV and INAOE. Measurements have been realized with different types of sensitive to charge preamplifiers determining the main characteristics which must be executed to be able to be employed with low capacitance detectors. As applications it has been possible to measure the irradiation time in a mammography machine and X-ray energy spectra have been obtained in the order of 14 KeV, with 4 KeV at ambient temperature. The future actions of project have been indicated and the possible applications of these detectors. (Author)

  5. Silicon P.I.N. Junctions used for studies of radiation damage

    Lanore, J.

    1964-06-01

    Irradiation of silicon P.I.N. junction has been studied primarily for the purpose of developing a radiation damage dosimeter, but also for the purpose of investigating silicon itself. It is known that the rate of recombination of electrons and holes is a linear function of defects introduced by neutron irradiation. Two methods have been used to measure that rate of recombination: forward characteristic measurements, recovery time measurements. In order to explain how these two parameters depend on recombination rate we have given a theory of the P.I.N. junction. We have also given an idea of the carrier lifetime dependence versus temperature. Annealing effects in the range of 70 to 700 K have also been studied, we found five annealing stages with corresponding activation energies. As an application for these studies, we developed a radiation damage dosimeter with which we made several experiments in facilities such as Naiade or Marias. (author) [fr

  6. Comparison of silicon pin diode detector fabrication processes using ion implantation and thermal doping

    Zhou, C.Z.; Warburton, W.K.

    1996-01-01

    Two processes for the fabrication of silicon p-i-n diode radiation detectors are described and compared. Both processes are compatible with conventional integrated-circuit fabrication techniques and yield very low leakage currents. Devices made from the process using boron thermal doping have about a factor of 2 lower leakage current than those using boron ion implantation. However, the boron thermal doping process requires additional process steps to remove boron skins. (orig.)

  7. An improved PIN photodetector with integrated JFET on high-resistivity silicon

    Dalla Betta, Gian-Franco; Piemonte, Claudio; Boscardin, Maurizio; Gregori, Paolo; Zorzi, Nicola; Fazzi, Alberto; Pignatel, Giorgio U.

    2006-01-01

    We report on a PIN photodetector integrated with a Junction Field Effect Transistor (JFET) on a high-resistivity silicon substrate. Owing to a modified fabrication technology, the electrical and noise characteristics of the JFET transistor have been enhanced with respect to the previous versions of the device, allowing the performance to be significantly improved. In this paper, the main design and technological aspects relevant to the proposed structure are addressed and experimental results from the electrical characterization are discussed

  8. Dark current spectroscopy of space and nuclear environment induced displacement damage defects in pinned photodiode based CMOS image sensors

    Belloir, Jean-Marc

    2016-01-01

    CMOS image sensors are envisioned for an increasing number of high-end scientific imaging applications such as space imaging or nuclear experiments. Indeed, the performance of high-end CMOS image sensors has dramatically increased in the past years thanks to the unceasing improvements of microelectronics, and these image sensors have substantial advantages over CCDs which make them great candidates to replace CCDs in future space missions. However, in space and nuclear environments, CMOS image sensors must face harsh radiation which can rapidly degrade their electro-optical performances. In particular, the protons, electrons and ions travelling in space or the fusion neutrons from nuclear experiments can displace silicon atoms in the pixels and break the crystalline structure. These displacement damage effects lead to the formation of stable defects and to the introduction of states in the forbidden bandgap of silicon, which can allow the thermal generation of electron-hole pairs. Consequently, non ionizing radiation leads to a permanent increase of the dark current of the pixels and thus a decrease of the image sensor sensitivity and dynamic range. The aim of the present work is to extend the understanding of the effect of displacement damage on the dark current increase of CMOS image sensors. In particular, this work focuses on the shape of the dark current distribution depending on the particle type, energy and fluence but also on the image sensor physical parameters. Thanks to the many conditions tested, an empirical model for the prediction of the dark current distribution induced by displacement damage in nuclear or space environments is experimentally validated and physically justified. Another central part of this work consists in using the dark current spectroscopy technique for the first time on irradiated CMOS image sensors to detect and characterize radiation-induced silicon bulk defects. Many types of defects are detected and two of them are identified

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

    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.

  10. Comparison of proton microbeam and gamma irradiation for the radiation hardness testing of silicon PIN diodes

    Jakšić, M.; Grilj, V.; Skukan, N.; Majer, M.; Jung, H. K.; Kim, J. Y.; Lee, N. H.

    2013-09-01

    Simple and cost-effective solutions using Si PIN diodes as detectors are presently utilized in various radiation-related applications in which excessive exposure to radiation degrades their charge transport properties. One of the conventional methods for the radiation hardness testing of such devices is time-consuming irradiation with electron beam or gamma-ray irradiation facilities, high-energy proton accelerators, or with neutrons from research reactors. Recently, for the purpose of radiation hardness testing, a much faster nuclear microprobe based approach utilizing proton irradiation has been developed. To compare the two different irradiation techniques, silicon PIN diodes have been irradiated with a Co-60 gamma radiation source and with a 6 MeV proton microbeam. The signal degradation in the silicon PIN diodes for both irradiation conditions has been probed by the IBIC (ion beam induced charge) technique, which can precisely monitor changes in charge collection efficiency. The results presented are reviewed on the basis of displacement damage calculations and NIEL (non-ionizing energy loss) concept.

  11. Effect of swift heavy Kr ions on complex permittivity of silicon PIN diode

    Li, Yun; Su, Ping; Yang, Zhimei; Ma, Yao; Gong, Min

    2016-01-01

    Highlights: • The complex permittivity has been studied on Si PIN irradiated by heavy Kr ions. • DLTS was used to investigate damages formed in PIN diode during irradiation. • The recombination of carriers has important influence on the complex permittivity. - Abstract: The complex permittivity has been researched on silicon PIN diodes irradiated by 2150 MeV heavy Kr ions in this article. The difference of complex permittivity spectra from 1 to 10^7 Hz between irradiated and unirradiated were observed and discussed. The current-voltage (I-V) and capacitance-voltage (C-V) characteristics were measured at room temperature (300 K) to study the change of electrical properties in diode after irradiation. Deep level transient spectroscopy (DLTS) was used to investigate damages caused by 2150 MeV heavy Kr ions in diode. Two extra electron traps were observed, which were located at E C -0.31 eV and E C -0.17 eV. It indicated that new defects have been formed in PIN diode during irradiation. A comparison of the results illustrated that not only the carrier density but also the recombination of electron-hole pair have important influences on the properties of complex permittivity. These results offer a further indication of the mechanism about the complex permittivity property of semiconductor device, which could help to make the applications for the semiconductor device controlled by electric signals come true in the fields of optoelectronic integrated circuits, plasma antenna and so on.

  12. Temperature dependence of the radiation induced change of depletion voltage in silicon PIN detectors

    Ziock, H.J.; Holzscheiter, K.; Morgan, A.; Palounek, A.P.T.; Ellison, J.; Heinson, A.P.; Mason, M.; Wimpenny, S.J.; Barberis, E.; Cartiglia, N.; Grillo, A.; O'Shaughnessy, K.; Rahn, J.; Rinaldi, P.; Rowe, W.A.; Sadrozinski, H.F.W.; Seiden, A.; Spencer, E.; Webster, A.; Wichmann, R.; Wilder, M.; Coupal, D.; Pal, T.

    1993-01-01

    The silicon microstrip detectors that will be used in the SDC experiment at the Superconducting Super Collider (SSC) will be exposed to very large fluences of charged particles, neutrons, and gammas. The authors present a study of how temperature affects the change in the depletion voltage of silicon PIN detectors damaged by radiation. They study the initial radiation damage and the short-term and long-term annealing of that damage as a function of temperature in the range from -10 degrees C to +50 degrees C, and as a function of 800 MeV proton fluence up to 1.5 x 10 14 p/cm 2 . They express the pronounced temperature dependencies in a simple model in terms of two annealing time constants which depend exponentially on the temperature

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

    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

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

    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...

  15. Effect of swift heavy Kr ions on complex permittivity of silicon PIN diode

    Li, Yun [Key Laboratory of Radiation Physics and Technology of Ministry of Education, Sichuan University, Chengdu 610064 (China); College of Physical Science and Technology, Sichuan University, Chengdu, Sichuan 610064 (China); Su, Ping, E-mail: pingsu@scu.edu.cn [Key Laboratory of Radiation Physics and Technology of Ministry of Education, Sichuan University, Chengdu 610064 (China); Key Lab of Microelectronics Sichuan Province, Sichuan University, Chengdu, Sichuan 610064 (China); College of Physical Science and Technology, Sichuan University, Chengdu, Sichuan 610064 (China); Yang, Zhimei; Ma, Yao [Key Lab of Microelectronics Sichuan Province, Sichuan University, Chengdu, Sichuan 610064 (China); College of Physical Science and Technology, Sichuan University, Chengdu, Sichuan 610064 (China); Gong, Min, E-mail: mgong@scu.edu.cn [Key Laboratory of Radiation Physics and Technology of Ministry of Education, Sichuan University, Chengdu 610064 (China); Key Lab of Microelectronics Sichuan Province, Sichuan University, Chengdu, Sichuan 610064 (China); College of Physical Science and Technology, Sichuan University, Chengdu, Sichuan 610064 (China)

    2016-12-01

    Highlights: • The complex permittivity has been studied on Si PIN irradiated by heavy Kr ions. • DLTS was used to investigate damages formed in PIN diode during irradiation. • The recombination of carriers has important influence on the complex permittivity. - Abstract: The complex permittivity has been researched on silicon PIN diodes irradiated by 2150 MeV heavy Kr ions in this article. The difference of complex permittivity spectra from 1 to 10^7 Hz between irradiated and unirradiated were observed and discussed. The current-voltage (I-V) and capacitance-voltage (C-V) characteristics were measured at room temperature (300 K) to study the change of electrical properties in diode after irradiation. Deep level transient spectroscopy (DLTS) was used to investigate damages caused by 2150 MeV heavy Kr ions in diode. Two extra electron traps were observed, which were located at E{sub C}-0.31 eV and E{sub C}-0.17 eV. It indicated that new defects have been formed in PIN diode during irradiation. A comparison of the results illustrated that not only the carrier density but also the recombination of electron-hole pair have important influences on the properties of complex permittivity. These results offer a further indication of the mechanism about the complex permittivity property of semiconductor device, which could help to make the applications for the semiconductor device controlled by electric signals come true in the fields of optoelectronic integrated circuits, plasma antenna and so on.

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

    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.

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

    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.

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

    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

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

    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.

  20. Integrated Amorphous Silicon p-i-n Temperature Sensor for CMOS Photonics

    Sandro Rao

    2016-01-01

    Full Text Available Hydrogenated amorphous silicon (a-Si:H shows interesting optoelectronic and technological properties that make it suitable for the fabrication of passive and active micro-photonic devices, compatible moreover with standard microelectronic devices on a microchip. A temperature sensor based on a hydrogenated amorphous silicon p-i-n diode integrated in an optical waveguide for silicon photonics applications is presented here. The linear dependence of the voltage drop across the forward-biased diode on temperature, in a range from 30 °C up to 170 °C, has been used for thermal sensing. A high sensitivity of 11.9 mV/°C in the bias current range of 34–40 nA has been measured. The proposed device is particularly suitable for the continuous temperature monitoring of CMOS-compatible photonic integrated circuits, where the behavior of the on-chip active and passive devices are strongly dependent on their operating temperature.

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

    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

  2. Silicon Waveguide with Lateral p-i-n Diode for Nonlinearity Compensation by On-Chip Optical Phase Conjugation

    Gajda, A.; Da Ros, Francesco; Porto da Silva, Edson

    2018-01-01

    A 1-dB Q-factor improvement through optical phase conjugation in a silicon waveguide with a lateral p-i-n diode enables BER

  3. A filter technique for optimising the photon energy response of a silicon pin diode dosemeter

    Olsher, R.H.; Eisen, Y.

    1996-01-01

    Unless they are energy compensated, silicon PIN diodes used in electronic pocket dosemeters, have significant over-response below 200 keV. Siemens is using three diodes in parallel with individual filters to produce excellent energy and angular response. An algorithm based on the photon spectrum of a single diode could be used to flatten the energy response. The commercial practice is to use a single diode with a simple filter to flatten the energy response, despite the mediocre low energy photon. The filter technique with an opening has been used for energy compensating GM detectors and proportional counters and a new variation of it has been investigated which compensates the energy response of a silicon PIN diode and maintains an extended low energy response. It uses a composite filter of two or more materials with several openings whose individual area is in the range of 15% to 25% of the diode's active area. One opening is centred over the diode's active area and others are located at the periphery of the active area to preserve a good polar response to ±45 o . Monte Carlo radiation transport methods were used to simulate the coupled electron-photon transport through a Hamamatsu S2506-01 diode and to determine the energy response of the diode for a variety of filters. In current mode, the resultant dosemeter energy response relative to air dose was within -15% and +30% for 0 o incidence over the energy range from 15 keV to 1 MeV. In pulse mode, the resultant dosemeter energy response was within -25% and +50% for 0 o incidence over the energy range from 30 keV to 10 MeV. For ±45 o incidence, the energy response was within -25% and +40% from 40 keV to 10 MeV. Theoretical viability of the filter technique has been shown in this work (Author)

  4. Effects of the intrinsic layer width on the band-to-band tunneling current in p-i-n GaN-based avalanche photodiodes

    Wang, Ling; Bao, Xichang; Zhang, Wenjing; Li, Chao; Yuan, Yonggang; Xu, Jintong; Zhang, Yan; Li, Xiangyang

    2009-01-01

    Dark current is critical for GaN-based avalanche photodiodes because it significantly increases the noise current and limits the multiplication factor. It has been found that the band-to-band tunneling current is the dominant origin of the dark current for avalanche photodiodes at the onset of breakdown voltage. Experimentally, for GaN-based avalanche photodiodes with a thinner intrinsic layer, the dark current increases nearly exponentially with the applied voltage even at a lower bias voltage. In this paper, the intrinsic layer (i-layer) width of GaN-based avalanche photodiodes has been varied to study its effect on the band-to-band tunneling current. A widely used equation was used to calculate the band-to-band tunneling current of avalanche photodiodes with different i-layer widths (i-layer 0.1 µm, 0.2 µm and 0.4 µm). At −40 V, the band-to-band tunneling current significantly reduces by a magnitude of 10 −15 A with an increase in the i-layer width from 0.1 µm to 0.2 µm, and a magnitude of 10 −29 A with an increase in the i-layer width from 0.2 µm to 0.4 µm. Then, GaN-based avalanche photodiodes (i-layer 0.1 µm, 0.2 µm and 0.4 µm) with different-sized mesa were fabricated. Also, the measurement of dark current of all three different structures was performed, and their multiplication factors were given

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

    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.

  6. High-speed and efficient silicon modulator based on forward-biased pin diodes

    Suguru eAkiyama

    2014-11-01

    Full Text Available Silicon modulators, which use the free-carrier-plasma effect, were studied, both analytically and experimentally. It was demonstrated that the loss-efficiency product, a-VpL, was a suitable figure of merit for silicon modulators that enabled their intrinsic properties to be compared. Subsequently, the dependence of VpL on frequency was expressed by using the electrical parameters of a phase shifter when the modulator was operated by assuming a simple driving configuration. A diode-based modulator operated in forward biased mode was expected from analyses to provide more efficient operation than that in reversed mode at high frequencies due to its large capacitance. We obtained an a-VpL of 9.5 dB-V at 12.5 GHz in experiments by using the fabricated phase shifter with pin diodes operated in forward biased mode. This a-VpL was comparable to the best modulators operated in depletion mode. The modulator exhibited a clear eye opening at 56 Gb/s operated by 2 V peak-to-peak signals that was achieved by incorporating such a phase shifter into a ring resonator.

  7. Characterization of Lateral Structure of the p-i-n Diode for Thin-Film Silicon Solar Cell.

    Kiaee, Zohreh; Joo, Seung Ki

    2018-03-01

    The lateral structure of the p-i-n diode was characterized for thin-film silicon solar cell application. The structure can benefit from a wide intrinsic layer, which can improve efficiency without increasing cell thickness. Compared with conventional thin-film p-i-n cells, the p-i-n diode lateral structure exploited direct light irradiation on the absorber layer, one-side contact, and bifacial irradiation. Considering the effect of different carrier lifetimes and recombinations, we calculated efficiency parameters by using a commercially available simulation program as a function of intrinsic layer width, as well as the distance between p/i or n/i junctions to contacts. We then obtained excellent parameter values of 706.52 mV open-circuit voltage, 24.16 mA/Cm2 short-circuit current, 82.66% fill factor, and 14.11% efficiency from a lateral cell (thickness = 3 μm; intrinsic layer width = 53 μm) in monofacial irradiation mode (i.e., only sunlight from the front side was considered). Simulation results of the cell without using rear-side reflector in bifacial irradiation mode showed 11.26% front and 9.72% rear efficiencies. Our findings confirmed that the laterally structured p-i-n cell can be a potentially powerful means for producing highly efficient, thin-film silicon solar cells.

  8. The measurement of phi 60 mm x 600 mu m silicon PIN detector gamma sensitivity and time respond

    Hu Meng Chun; Ye Wen Ying

    2002-01-01

    phi 60 mm x 600 mu m silicon PIN detector is a large area and high sensitive one which has been developed in near years. The authors have measured their gamma sensitivity and the time response. The experiment and theoretical calculated results in: sup 6 sup 0 Co gamma sensitivity is about 5 fC centre dot cm sup 2 /MeV, the rise time is about 10 ns and the half-high-width time is about 35 ns

  9. Prediction of the Response of the Commercial BPW34FS Silicon p-i-n Diode Used as Radiation Monitoring Sensors up to Very High Fluences

    Mekki, J; Glaser, M; Moll, M; Dusseau, L

    2010-01-01

    The effect of radiation damage on Silicon p-i-n diodes has been studied. I-V characteristics of BPW34FS silicon p-i-n diodes irradiated with 24 GeV/c protons up to 6.3 x 10(15) n(eq)/cm(2) have been measured and analyzed. A parameterization predicting the radiation response in the fluence range relevant for the use of the diodes as radiation monitors in Super-LHC experiments is presented.

  10. Characterisation of Al{sub 0.52}In{sub 0.48}P mesa p-i-n photodiodes for X-ray photon counting spectroscopy

    Butera, S., E-mail: S.Butera@sussex.ac.uk; Lioliou, G.; Barnett, A. M. [Semiconductor Materials and Device Laboratory, School of Engineering and Informatics, University of Sussex, Brighton BN1 9QT (United Kingdom); Krysa, A. B. [EPSRC National Centre for III-V Technologies, University of Sheffield, Mappin Street, Sheffield S1 3JD (United Kingdom)

    2016-07-14

    Results characterising the performance of thin (2 μm i-layer) Al{sub 0.52}In{sub 0.48}P p{sup +}-i-n{sup +} mesa photodiodes for X-ray photon counting spectroscopy are reported at room temperature. Two 200 μm diameter and two 400 μm diameter Al{sub 0.52}In{sub 0.48}P p{sup +}-i-n{sup +} mesa photodiodes were studied. Dark current results as a function of applied reverse bias are shown; dark current densities <3 nA/cm{sup 2} were observed at 30 V (150 kV/cm) for all the devices analysed. Capacitance measurements as a function of applied reverse bias are also reported. X-ray spectra were collected using 10 μs shaping time, with the device illuminated by an {sup 55}Fe radioisotope X-ray source. Experimental results showed that the best energy resolution (FWHM) achieved at 5.9 keV was 930 eV for the 200 μm Al{sub 0.52}In{sub 0.48}P diameter devices, when reverse biased at 15 V. System noise analysis was also carried out, and the different noise contributions were computed.

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

    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)

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

    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

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

    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.

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

    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)

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

    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.

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

    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.

  17. Luminescence in amorphous silicon p-i-n diodes under double-injection dispersive-transport-controlled recombination

    Han, D.; Wang, K.; Yeh, C.; Yang, L.; Deng, X.; Von Roedern, B.

    1997-01-01

    The temperature and electric-field dependence of the forward bias current and the electroluminescence (EL) in hydrogenated amorphous silicon (a-Si:H) p-i-n and n-i-p diodes have been studied. Both the current and the EL efficiency temperature dependence show three regions depending on either hopping-controlled or multiple-trapping or ballistic transport mechanisms. Comparing the thermalization-controlled geminate recombination processes of photoluminescence to the features of EL, the differences can be explained by transport-controlled nongeminate recombination in trap-rich materials. copyright 1997 The American Physical Society

  18. 20 Gbps operation of membrane-based GaInAs/InP waveguide-type p-i-n photodiode bonded on Si substrate

    Gu, Zhichen; Inoue, Daisuke; Amemiya, Tomohiro; Nishiyama, Nobuhiko; Arai, Shigehisa

    2018-02-01

    A GaInAs/InP waveguide-type p-i-n membrane photodetector is shown to be a strong candidate for on-chip optical interconnection. A responsivity of 0.95 A/W is estimated for a device length of 30 µm. The 3 dB cutoff frequency is measured to be 13.3 GHz at a reverse bias of 3 V, which is in good agreement with the observed clear eye opening pattern up to 20 Gbps for a non-return-to-zero signal. Moreover, a bit error rate of less than 1 × 10-9 is obtained at data rates of 20 and 10 Gbps with input powers of -10 and -13 dBm, respectively.

  19. 10 μ m-thick four-quadrant transmissive silicon photodiodes for beam position monitor application: electrical characterization and gamma irradiation effects

    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.

  20. Method of producing p-i-n structures by compensation of lithium ions from both side of silicon

    Muminov, R.A.; Radjapov, S.A.; Saymbetov, A.K.; Tursunkulov, O.M.; Pindurin, Yu.S.

    2007-01-01

    Full text: Semiconductor nuclear radiation detectors are needed to solve certain problems in nuclear spectroscopy. The development of efficiency detectors became possible with advances in growing high purify silicon single crystals with the required properties, satisfying the requirements for obtaining detectors based on them. One important requirement for obtaining detectors with sensitive area is that its resistance must be high. This is achieved by using the lithium ion drift process in the volume of the semiconductor detector. Thus it has been developed and created silicon semiconductor nuclear radiation detectors with vide range of diameter of sensitive area up to 100 mm and thickness (from 1mm to 10mm). At present work a new method for producing p-i-n structures was developed to decrease substantially the time required for compensation of silicon by lithium ions and to eliminate at the same time the negative consequences of holding the crystal at a high temperature and under a high voltage. Drift of lithium ions from two ends of prepared samples is conducted to a depth sufficient for the required compensation of the initial acceptor impurity in silicon. The method described above was used to fabricate a batch of Si(Li) detectors with a 1-10 mm thick and 10-110 mm in diameter sensitive region. The thickness of the sensitive region was determined by performing standard measurements and chemical pigmentation. Advantages of detectors are they have improved properties and less time for compensation of lithium ions. (authors)

  1. Silicon PIN diode based electron-gamma coincidence detector system for Noble Gases monitoring.

    Khrustalev, K; Popov, V Yu; Popov, Yu S

    2017-08-01

    We present a new second generation SiPIN based electron-photon coincidence detector system developed by Lares Ltd. for use in the Noble Gas measurement systems of the International Monitoring System and the On-site Inspection verification regimes of the Comprehensive Nuclear-Test Ban Treaty (CTBT). The SiPIN provide superior energy resolution for electrons. Our work describes the improvements made in the second generation detector cells and the potential use of such detector systems for other applications such as In-Situ Kr-85 measurements for non-proliferation purposes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Nano-multiplication region avalanche photodiodes and arrays

    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.

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

    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

  4. Investigation of avalanche photodiodes

    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.

  5. Investigation of avalanche photodiodes

    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

  6. Silicon PIN diode hybrid arrays for charged particle detection: Building blocks for vertex detectors at the SSC

    Kramer, G.; Gaalema, S.; Shapiro, S.L.; Dunwoodie, W.M.; Arens, J.F.; Jernigan, J.G.

    1989-05-01

    Two-dimensional arrays of solid state detectors have long been used in visible and infrared systems. Hybrid arrays with separately optimized detector and readout substrates have been extensively developed for infrared sensors. The characteristics and use of these infrared readout chips with silicon PIN diode arrays produced by MICRON SEMICONDUCTOR for detecting high-energy particles are reported. Some of these arrays have been produced in formats as large as 512 /times/ 512 pixels; others have been radiation hardened to total dose levels beyond 1 Mrad. Data generation rates of 380 megasamples/second have been achieved. Analog and digital signal transmission and processing techniques have also been developed to accept and reduce these high data rates. 9 refs., 15 figs., 2 tabs

  7. Phase regeneration of DPSK signals in a silicon waveguide with reverse-biased p-i-n junction

    Da Ros, Francesco; Vukovic, Dragana; Gajda, Andrzej

    2014-01-01

    Phase regeneration of differential phase-shift keying (DPSK) signals is demonstrated using a silicon waveguide as nonlinear medium for the first time. A p-i-n junction across the waveguide enables decreasing the nonlinear losses introduced by free-carrier absorption (FCA), thus allowing phase......-sensitive extinction ratios as high as 20 dB to be reached under continuous-wave (CW) pumping operation. Furthermore the regeneration properties are investigated under dynamic operation for a 10-Gb/s DPSK signal degraded by phase noise, showing receiver sensitivity improvements above 14 dB. Different phase noise...... frequencies and amplitudes are examined, resulting in an improvement of the performance of the regenerated signal in all the considered cases....

  8. A Low-Noise X-ray Astronomical Silicon-On-Insulator Pixel Detector Using a Pinned Depleted Diode Structure.

    Kamehama, Hiroki; Kawahito, Shoji; Shrestha, Sumeet; Nakanishi, Syunta; Yasutomi, Keita; Takeda, Ayaki; Tsuru, Takeshi Go; Arai, Yasuo

    2017-12-23

    This paper presents a novel full-depletion Si X-ray detector based on silicon-on-insulator pixel (SOIPIX) technology using a pinned depleted diode structure, named the SOIPIX-PDD. The SOIPIX-PDD greatly reduces stray capacitance at the charge sensing node, the dark current of the detector, and capacitive coupling between the sensing node and SOI circuits. These features of the SOIPIX-PDD lead to low read noise, resulting high X-ray energy resolution and stable operation of the pixel. The back-gate surface pinning structure using neutralized p-well at the back-gate surface and depleted n-well underneath the p-well for all the pixel area other than the charge sensing node is also essential for preventing hole injection from the p-well by making the potential barrier to hole, reducing dark current from the Si-SiO₂ interface and creating lateral drift field to gather signal electrons in the pixel area into the small charge sensing node. A prototype chip using 0.2 μm SOI technology shows very low readout noise of 11.0 e - rms , low dark current density of 56 pA/cm² at -35 °C and the energy resolution of 200 eV(FWHM) at 5.9 keV and 280 eV (FWHM) at 13.95 keV.

  9. Progress report on the use of hybrid silicon pin diode arrays in high energy physics

    Shapiro, S.L.; Jernigan, J.G.; Arens, J.F.

    1990-05-01

    We report on the successful effort to develop hybrid PIN diode arrays and to demonstrate their potential as components of vertex detectors. Hybrid pixel arrays have been fabricated by the Hughes Aircraft Co. by bump-bonding readout chips developed by Hughes to an array of PIN diodes manufactured by Micron Semiconductor Inc. These hybrid pixel arrays were constructed in two configurations. One array format has 10 x 64 pixels, each 120 μm square; and the other format has 256 x 156 pixels, each 30 μm square. In both cases, the thickness of the PIN diode layer is 300 μm. Measurements of detector performance show that excellent position resolution can be achieved by interpolation. By determining the centroid of the charge cloud which spreads charge into a number of neighboring pixels, a spatial resolution of a few microns has been attained. The noise has been measured to be about 300 electrons (rms) at room temperature, as expected from KTC and dark current considerations, yielding a signal-to-noise ratio of about 100 for minimum ionizing particles. 4 refs., 17 figs

  10. Defects influence on short circuit current density in p-i-n silicon solar cell

    Wagah F Mohamad; Alhan M Mustafa

    2006-01-01

    The admittance analysis method has been used to calculate the collection efficiency and the short circuit current density in a-Si:H p-i-n solar cell, as a function of the thickness of i-layer. Its is evident that the results of the short circuit current can be used to determine the optimal thickness of the i-layer of a cell, and it will be more accurate in comparison with the previous studies using a constant generation rate or an empirical exponential function for the generation of charge carriers throughout the i-layer

  11. Highly transparent front electrodes with metal fingers for p-i-n thin-film silicon solar cells

    Moulin Etienne

    2015-01-01

    Full Text Available The optical and electrical properties of transparent conductive oxides (TCOs, traditionally used in thin-film silicon (TF-Si solar cells as front-electrode materials, are interlinked, such that an increase in TCO transparency is generally achieved at the cost of reduced lateral conductance. Combining a highly transparent TCO front electrode of moderate conductance with metal fingers to support charge collection is a well-established technique in wafer-based technologies or for TF-Si solar cells in the substrate (n-i-p configuration. Here, we extend this concept to TF-Si solar cells in the superstrate (p-i-n configuration. The metal fingers are used in conjunction with a millimeter-scale textured foil, attached to the glass superstrate, which provides an antireflective and retroreflective effect; the latter effect mitigates the shadowing losses induced by the metal fingers. As a result, a substantial increase in power conversion efficiency, from 8.7% to 9.1%, is achieved for 1-μm-thick microcrystalline silicon solar cells deposited on a highly transparent thermally treated aluminum-doped zinc oxide layer combined with silver fingers, compared to cells deposited on a state-of-the-art zinc oxide layer.

  12. Silicon radiation detector

    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.)

  13. Low-cost amplifier for alpha detection with photodiode

    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)

  14. Recombination centers and electrical characteristics in silicon power p-i-n diodes irradiated with high energy electrons

    Fuochi, P.G.; Martelli, A.; Passerini, B.; Zambelli, M.

    1988-01-01

    Recombination centers introduced by irradiation with 12 MeV electrons in large area silicon diodes with p-i-n structure are studied with the Deep Level Transient Spectroscopy technique (DLTS). The effects of these levels on the electrical characteristics of the devices are related to their position Esub(t) in the silicon forbidden gap, their concentration and their electron capture cross section. Changes of defect configuration during an annealing process at 360 0 C have been observed and a detailed analysis of the DLTS spectra has shown a complex defect pattern. Four major recombination centers have been identified: Esub(c) - Esub(t) = 0.17 eV, Esub(c) - Esub(t) = 0.19 eV, Esub(c) -Esub(t) 0.31 eV, Esub(c) - Esub(t) = 0.39 eV, where Esub(c) is the energy corresponding to the lower limit of the conduction band. The first energy level, known as A-center, is the dominant recombination level controlling the minority carrier lifetime after room temperature irradiation. As the annealing proceeds the center at Esub(c) - Esub(t) = 0.31 eV becomes the dominant one. The complex structure of the centers has been studied and demonstrated with the aid of proper modelling implemented on a set of numerical simulation tools. In this way it has been possible to analyze more accurately the defect kinetics during annealing. The study of the defect behaviour during the annealing process has resulted in an improved application of electron irradiation as a standard production technique in the manufacturing process of high power devices. (author)

  15. Dual-polarization wavelength conversion of 16-QAM signals in a single silicon waveguide with a lateral p-i-n diode [Invited

    Da Ros, Francesco; Gajda, Andrzej; Liebig, Erik

    2018-01-01

    with an optical signal-to-noise ratio penalty below 0.7 dB. High-quality converted signals are generated thanks to the low polarization dependence (≤0.5 dB) and the high conversion efficiency (CE) achievable. The strong Kerr nonlinearity in silicon and the decrease of detrimental free-carrier absorption due......A polarization-diversity loop with a silicon waveguide with a lateral p-i-n diode as a nonlinear medium is used to realize polarization insensitive four-wave mixing. Wavelength conversion of seven dual-polarization 16-quadrature amplitude modulation (QAM) signals at 16 GBd is demonstrated...

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

    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)

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

    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. Silicon P.I.N. Junctions used for studies of radiation damage; Etude de l'irradiation aux neutrons rapides du silicium au moyen de jonctions P.I.N

    Lanore, J [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1964-06-01

    Irradiation of silicon P.I.N. junction has been studied primarily for the purpose of developing a radiation damage dosimeter, but also for the purpose of investigating silicon itself. It is known that the rate of recombination of electrons and holes is a linear function of defects introduced by neutron irradiation. Two methods have been used to measure that rate of recombination: forward characteristic measurements, recovery time measurements. In order to explain how these two parameters depend on recombination rate we have given a theory of the P.I.N. junction. We have also given an idea of the carrier lifetime dependence versus temperature. Annealing effects in the range of 70 to 700 K have also been studied, we found five annealing stages with corresponding activation energies. As an application for these studies, we developed a radiation damage dosimeter with which we made several experiments in facilities such as Naiade or Marias. (author) [French] L'irradiation de structures P.I.N. etait faite dans le but d'etudier principalement la mise au point d'un dosimetre a ''radiation damage'' et aussi pour etudier plus profondement le silicium lui-meme. On sait que le taux de recombinaison electrons-trous est une fonction lineaire du taux de defauts introduits par irradiation aux neutrons. Deux methodes ont ete utilisees pour atteindre ce taux de recombinaison: mesures de la caracteristique directe, mesures du temps de retournement. Pour expliquer de quelle facon ces parametres dependent du taux de recombinaison. Nous avons donne une theorie de la jonction P.I.N. Nous avons aussi donne l'allure des variations du temps de vie des porteurs en fonction de la temperature. Nous avons d'autre part effectue des recuits entre 70 et 700 K, domaine dans lequel nous avons trouve cinq etapes de ''guerison'' avec les energies d'activation correspondantes. En application de ces etudes nous avons mis ou point un dosimetre a ''radiation damage'' avec lequel nous avons effectue des

  19. Silicon P.I.N. Junctions used for studies of radiation damage; Etude de l'irradiation aux neutrons rapides du silicium au moyen de jonctions P.I.N

    Lanore, J. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1964-06-01

    Irradiation of silicon P.I.N. junction has been studied primarily for the purpose of developing a radiation damage dosimeter, but also for the purpose of investigating silicon itself. It is known that the rate of recombination of electrons and holes is a linear function of defects introduced by neutron irradiation. Two methods have been used to measure that rate of recombination: forward characteristic measurements, recovery time measurements. In order to explain how these two parameters depend on recombination rate we have given a theory of the P.I.N. junction. We have also given an idea of the carrier lifetime dependence versus temperature. Annealing effects in the range of 70 to 700 K have also been studied, we found five annealing stages with corresponding activation energies. As an application for these studies, we developed a radiation damage dosimeter with which we made several experiments in facilities such as Naiade or Marias. (author) [French] L'irradiation de structures P.I.N. etait faite dans le but d'etudier principalement la mise au point d'un dosimetre a ''radiation damage'' et aussi pour etudier plus profondement le silicium lui-meme. On sait que le taux de recombinaison electrons-trous est une fonction lineaire du taux de defauts introduits par irradiation aux neutrons. Deux methodes ont ete utilisees pour atteindre ce taux de recombinaison: mesures de la caracteristique directe, mesures du temps de retournement. Pour expliquer de quelle facon ces parametres dependent du taux de recombinaison. Nous avons donne une theorie de la jonction P.I.N. Nous avons aussi donne l'allure des variations du temps de vie des porteurs en fonction de la temperature. Nous avons d'autre part effectue des recuits entre 70 et 700 K, domaine dans lequel nous avons trouve cinq etapes de ''guerison'' avec les energies d'activation correspondantes. En application de ces etudes nous avons mis ou point un

  20. Contact pin-printing of albumin-fungicide conjugate for silicon nitride-based sensors biofunctionalization: Multi-technique surface analysis for optimum immunoassay performance

    Gajos, Katarzyna, E-mail: katarzyna.gajos@doctoral.uj.edu.pl [M. Smoluchowski Institute of Physics, Jagiellonian University, Łojasiewicza, 11, 30-348 Kraków (Poland); Budkowski, Andrzej [M. Smoluchowski Institute of Physics, Jagiellonian University, Łojasiewicza, 11, 30-348 Kraków (Poland); Tsialla, Zoi; Petrou, Panagiota [Institute of Nuclear & Radiological Sciences & Technology, Energy & Safety, NCSR Demokritos, P. Grigoriou & Neapoleos St., Aghia Paraksevi 15310, Athens (Greece); Awsiuk, Kamil; Dąbczyński, Paweł [M. Smoluchowski Institute of Physics, Jagiellonian University, Łojasiewicza, 11, 30-348 Kraków (Poland); Bernasik, Andrzej [Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, Mickiewicza 30, 30-059 Kraków (Poland); Academic Centre for Materials and Nanotechnology, AGH University of Science and Technology, Mickiewicza 30, 30-059 Kraków (Poland); Rysz, Jakub [M. Smoluchowski Institute of Physics, Jagiellonian University, Łojasiewicza, 11, 30-348 Kraków (Poland); Misiakos, Konstantinos; Raptis, Ioannis [Department of Microelectronics, Institute of Nanoscience and Nanotechnology, NCSR Demokritos, P. Grigoriou & Neapoleos St., Aghia Paraksevi 15310, Athens (Greece); Kakabakos, Sotirios [Institute of Nuclear & Radiological Sciences & Technology, Energy & Safety, NCSR Demokritos, P. Grigoriou & Neapoleos St., Aghia Paraksevi 15310, Athens (Greece)

    2017-07-15

    Highlights: • Contact pin-printing of overlapping probe spots and spotting by hand are compared. • Contact pin-printing favors probe immobilization with two-fold higher surface density. • Incomplete monolayer develops to bilayer as printing solution concentration increases. • Blocking molecules complete probe monolayer but reduce probe bilayer. • Surface immunoreaction increases with probe concentration in printing solution. - Abstract: Mass fabrication of integrated biosensors on silicon chips is facilitated by contact pin-printing, applied for biofunctionalization of individual Si{sub 3}N{sub 4}-based transducers at wafer-scale. To optimize the biofunctionalization for immunochemical (competitive) detection of fungicide thiabendazole (TBZ), Si{sub 3}N{sub 4} surfaces are modified with (3-aminopropyl)triethoxysilane and examined after: immobilization of BSA-TBZ conjugate (probe) from solutions with different concentration, blocking with bovine serum albumin (BSA), and immunoreaction with a mouse monoclonal antibody against TBZ. Nanostructure, surface density, probe composition and coverage uniformity of protein layers are evaluated with Atomic Force Microscopy, Spectroscopic Ellipsometry, Time-of-Flight Secondary Ion Mass Spectrometry and X-ray Photoelectron Spectroscopy. Contact pin-printing of overlapping probe spots is compared with hand spotted areas. Contact pin-printing resulted in two-fold increase of immobilized probe surface density as compared to hand spotting. Regarding BSA-TBZ immobilization, an incomplete monolayer develops into a bilayer as the concentration of BSA-TBZ molecules in the printing solution increases from 25 to 100 μg/mL. Upon blocking, however, a complete protein monolayer is formed for all the BSA-TBZ concentrations used. Free surface sites are filled with BSA for low surface coverage with BSA-TBZ, whereas loosely bound BSA-TBZ molecules are removed from the BSA-TBZ bilayer. As a consequence immunoreaction efficiency

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

    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)

  2. Advances in the project about Pin type silicon radiation detectors; Avances en el proyecto sobre detectores de radiacion de silicio tipo PIN

    Ramirez F, J. [Instituto Nacional de Investigaciones Nucleares, Laboratorio de Detectores de Radiacion, A.P. 18-1027, 11801 Mexico D.F. (Mexico); Cerdeira, A.; Aceves, M.; Diaz, A.; Estrada, M.; Rosales, P.; Cabal, A.E.; Montano L, M.; Leyva, A

    1998-07-01

    The obtained advances in the collaboration project ININ-CINVESTAV about development of Pin type semiconductor radiation detectors here are presented. It has been characterized the response to different types of radiation made in CINVESTAV and INAOE. Measurements have been realized with different types of sensitive to charge preamplifiers determining the main characteristics which must be executed to be able to be employed with low capacitance detectors. As applications it has been possible to measure the irradiation time in a mammography machine and X-ray energy spectra have been obtained in the order of 14 KeV, with 4 KeV at ambient temperature. The future actions of project have been indicated and the possible applications of these detectors. (Author)

  3. High-performance silicon nanowire bipolar phototransistors

    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.

  4. Contact pin-printing of albumin-fungicide conjugate for silicon nitride-based sensors biofunctionalization: Multi-technique surface analysis for optimum immunoassay performance

    Gajos, Katarzyna; Budkowski, Andrzej; Tsialla, Zoi; Petrou, Panagiota; Awsiuk, Kamil; Dąbczyński, Paweł; Bernasik, Andrzej; Rysz, Jakub; Misiakos, Konstantinos; Raptis, Ioannis; Kakabakos, Sotirios

    2017-07-01

    Mass fabrication of integrated biosensors on silicon chips is facilitated by contact pin-printing, applied for biofunctionalization of individual Si3N4-based transducers at wafer-scale. To optimize the biofunctionalization for immunochemical (competitive) detection of fungicide thiabendazole (TBZ), Si3N4 surfaces are modified with (3-aminopropyl)triethoxysilane and examined after: immobilization of BSA-TBZ conjugate (probe) from solutions with different concentration, blocking with bovine serum albumin (BSA), and immunoreaction with a mouse monoclonal antibody against TBZ. Nanostructure, surface density, probe composition and coverage uniformity of protein layers are evaluated with Atomic Force Microscopy, Spectroscopic Ellipsometry, Time-of-Flight Secondary Ion Mass Spectrometry and X-ray Photoelectron Spectroscopy. Contact pin-printing of overlapping probe spots is compared with hand spotted areas. Contact pin-printing resulted in two-fold increase of immobilized probe surface density as compared to hand spotting. Regarding BSA-TBZ immobilization, an incomplete monolayer develops into a bilayer as the concentration of BSA-TBZ molecules in the printing solution increases from 25 to 100 μg/mL. Upon blocking, however, a complete protein monolayer is formed for all the BSA-TBZ concentrations used. Free surface sites are filled with BSA for low surface coverage with BSA-TBZ, whereas loosely bound BSA-TBZ molecules are removed from the BSA-TBZ bilayer. As a consequence immunoreaction efficiency increases with the printing probe concentration.

  5. Actinide oxide photodiode and nuclear battery

    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.

  6. Gallium-based avalanche photodiode optical crosstalk

    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

  7. EFFECT OF SILICON, NITROGEN AND POTASSIUM IN THE INCIDENCE OF TOMATO PIN WORM IN INDUSTRIAL TOMATO PLANTS

    Marília Cristina dos Santos2*

    2013-12-01

    of two stems per plant. It was observed a decrease in the number of pinworm leaf mines with an increase in silicon and potassium doses and an increase in the number of mines with an increase on nitrogen doses.

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

    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.

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

    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)

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

    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)

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

    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.

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

    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...

  13. Electron transport through rectifying self-assembled monolayer diodes on silicon: Fermi-level pinning at the molecule-metal interface.

    Lenfant, S; Guerin, D; Tran Van, F; Chevrot, C; Palacin, S; Bourgoin, J P; Bouloussa, O; Rondelez, F; Vuillaume, D

    2006-07-20

    We report the synthesis and characterization of molecular rectifying diodes on silicon using sequential grafting of self-assembled monolayers of alkyl chains bearing a pi group at their outer end (Si/sigma-pi/metal junctions). We investigate the structure-performance relationships of these molecular devices, and we examine the extent to which the nature of the pi end group (change in the energy position of their molecular orbitals) drives the properties of these molecular diodes. Self-assembled monolayers of alkyl chains (different chain lengths from 6 to 15 methylene groups) functionalized by phenyl, anthracene, pyrene, ethylene dioxythiophene, ethylene dioxyphenyl, thiophene, terthiophene, and quaterthiophene were synthesized and characterized by contact angle measurements, ellipsometry, Fourier transform infrared spectroscopy, and atomic force microscopy. We demonstrate that reasonably well-packed monolayers are obtained in all cases. Their electrical properties were assessed by dc current-voltage characteristics and high-frequency (1-MHz) capacitance measurements. For all of the pi groups investigated here, we observed rectification behavior. These results extend our preliminary work using phenyl and thiophene groups (Lenfant et al., Nano Lett. 2003, 3, 741). The experimental current-voltage curves were analyzed with a simple analytical model, from which we extracted the energy position of the molecular orbital of the pi group in resonance with the Fermi energy of the electrodes. We report experimental studies of the band lineup in these silicon/alkyl pi-conjugated molecule/metal junctions. We conclude that Fermi-level pinning at the pi group/metal interface is mainly responsible for the observed absence of a dependence of the rectification effect on the nature of the pi groups, even though the groups examined were selected to have significant variations in their electronic molecular orbitals.

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

    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...

  15. Pin care

    ... Drugs & Supplements Videos & Tools Español You Are Here: Home → Medical Encyclopedia → Pin care URL of this page: //medlineplus.gov/ency/patientinstructions/000481.htm Pin care To use the sharing features on this page, please enable JavaScript. Broken bones can be fixed in surgery with metal ...

  16. Development of a gamma dosimeter using a photodiode

    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

  17. Electron Beam Induced Radiation Damage of the Semiconductor Radiation Detector based on Silicon

    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

  18. Enhancing the far-UV sensitivity of silicon CMOS imaging arrays

    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.

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

    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.

  20. Happy Pinning

    Fausing, Bent

    2012-01-01

    This is about Pinterest, but with a different approach than usual to social networks. Pinterest is an image site par excellence. The images are as Windows that open outwards and also lets us look inwards and displays the soul and heart, the unintentional or pre-conscious desires. Happy Pinning!...

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

    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.

  2. Response of commercial photodiodes for application in alpha spectrometry

    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)

  3. Highly Efficient p-i-n Type Organic Light-emitting Diodes Using ...

    operating voltage of 3.0 V. In addition, impressive characteristics of white .... low voltage drops in the transport layers due to their ... thermal evaporation in high vacuum or organic vapor ... the calibrated silicon photodiode above the OLEDs.

  4. Radiation effects in the Si-PIN detector on the Near Earth Asteroid Rendezvous mission

    Starr, R; Evans, L G; Floyd, S R; McClanahan, T P; Trombka, J I; Goldsten, J O; Maurer, R H; McNutt, R L; Roth, D R

    1999-01-01

    A Si-PIN photodiode is being used as a solar X-ray monitor on the X-ray/gamma-ray spectrometer experiment which is flying on the Near Earth Asteroid Rendezvous spacecraft. Since its launch in February 1996 this photodiode has experienced several brief failures. These anomalies and other performance characteristics will be described. Efforts to reproduce these failures in ground tests with flight spare equipment will also be discussed.

  5. Spectroscopic amplifier for pin diode; Amplificador espectroscopico para diodo Pin

    Alonso M, M. S.; Hernandez D, V. M.; Vega C, H. R., E-mail: bebe.luna_s@hotmail.com [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico)

    2014-10-15

    The photodiode remains the basic choice for the photo-detection and is widely used in optical communications, medical diagnostics and field of corpuscular radiation. In detecting radiation it has been used for monitoring radon and its progeny and inexpensive spectrometric systems. The development of a spectroscopic amplifier for Pin diode is presented which has the following characteristics: canceler Pole-Zero (P/Z) with a time constant of 8 μs; constant gain of 57, suitable for the acquisition system; 4th integrator Gaussian order to waveform change of exponential input to semi-Gaussian output and finally a stage of baseline restorer which prevents Dc signal contribution to the next stage. The operational amplifier used is the TLE2074 of BiFET technology of Texas Instruments with 10 MHz bandwidth, 25 V/μs of slew rate and a noise floor of 17 nv/(Hz)1/2. The integrated circuit has 4 operational amplifiers and in is contained the total of spectroscopic amplifier that is the goal of electronic design. The results show like the exponential input signal is converted to semi-Gaussian, modifying only the amplitude according to the specifications in the design. The total system is formed by the detector, which is the Pin diode, a sensitive preamplifier to the load, the spectroscopic amplifier that is what is presented and finally a pulse height analyzer (Mca) which is where the spectrum is shown. (Author)

  6. Spectroscopic amplifier for pin diode

    Alonso M, M. S.; Hernandez D, V. M.; Vega C, H. R.

    2014-10-01

    The photodiode remains the basic choice for the photo-detection and is widely used in optical communications, medical diagnostics and field of corpuscular radiation. In detecting radiation it has been used for monitoring radon and its progeny and inexpensive spectrometric systems. The development of a spectroscopic amplifier for Pin diode is presented which has the following characteristics: canceler Pole-Zero (P/Z) with a time constant of 8 μs; constant gain of 57, suitable for the acquisition system; 4th integrator Gaussian order to waveform change of exponential input to semi-Gaussian output and finally a stage of baseline restorer which prevents Dc signal contribution to the next stage. The operational amplifier used is the TLE2074 of BiFET technology of Texas Instruments with 10 MHz bandwidth, 25 V/μs of slew rate and a noise floor of 17 nv/(Hz)1/2. The integrated circuit has 4 operational amplifiers and in is contained the total of spectroscopic amplifier that is the goal of electronic design. The results show like the exponential input signal is converted to semi-Gaussian, modifying only the amplitude according to the specifications in the design. The total system is formed by the detector, which is the Pin diode, a sensitive preamplifier to the load, the spectroscopic amplifier that is what is presented and finally a pulse height analyzer (Mca) which is where the spectrum is shown. (Author)

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

    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).

  8. Hydrogenated amorphous silicon p-i-n solar cells deposited under well controlled ion bombardment using pulse-shaped substrate biasing

    Wank, M. A.; van Swaaij, R.; R. van de Sanden,; Zeman, M.

    2012-01-01

    We applied pulse-shaped biasing (PSB) to the expanding thermal plasma deposition of intrinsic hydrogenated amorphous silicon layers at substrate temperatures of 200 degrees C and growth rates of about 1?nm/s. Fourier transform infrared spectroscopy of intrinsic films showed a densification with

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

    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.

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

    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...

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

    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.

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

    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

  13. Role of SiNx Barrier Layer on the Performances of Polyimide Ga2O3-doped ZnO p-i-n Hydrogenated Amorphous Silicon Thin Film Solar Cells

    Wang, Fang-Hsing; Kuo, Hsin-Hui; Yang, Cheng-Fu; Liu, Min-Chu

    2014-01-01

    In this study, silicon nitride (SiNx) thin films were deposited on polyimide (PI) substrates as barrier layers by a plasma enhanced chemical vapor deposition (PECVD) system. The gallium-doped zinc oxide (GZO) thin films were deposited on PI and SiNx/PI substrates at room temperature (RT), 100 and 200 °C by radio frequency (RF) magnetron sputtering. The thicknesses of the GZO and SiNx thin films were controlled at around 160 ± 12 nm and 150 ± 10 nm, respectively. The optimal deposition parameters for the SiNx thin films were a working pressure of 800 × 10−3 Torr, a deposition power of 20 W, a deposition temperature of 200 °C, and gas flowing rates of SiH4 = 20 sccm and NH3 = 210 sccm, respectively. For the GZO/PI and GZO-SiNx/PI structures we had found that the GZO thin films deposited at 100 and 200 °C had higher crystallinity, higher electron mobility, larger carrier concentration, smaller resistivity, and higher optical transmittance ratio. For that, the GZO thin films deposited at 100 and 200 °C on PI and SiNx/PI substrates with thickness of ~000 nm were used to fabricate p-i-n hydrogenated amorphous silicon (α-Si) thin film solar cells. 0.5% HCl solution was used to etch the surfaces of the GZO/PI and GZO-SiNx/PI substrates. Finally, PECVD system was used to deposit α-Si thin film onto the etched surfaces of the GZO/PI and GZO-SiNx/PI substrates to fabricate α-Si thin film solar cells, and the solar cells’ properties were also investigated. We had found that substrates to get the optimally solar cells’ efficiency were 200 °C-deposited GZO-SiNx/PI. PMID:28788494

  14. Role of SiNx Barrier Layer on the Performances of Polyimide Ga2O3-doped ZnO p-i-n Hydrogenated Amorphous Silicon Thin Film Solar Cells

    Fang-Hsing Wang

    2014-02-01

    Full Text Available In this study, silicon nitride (SiNx thin films were deposited on polyimide (PI substrates as barrier layers by a plasma enhanced chemical vapor deposition (PECVD system. The gallium-doped zinc oxide (GZO thin films were deposited on PI and SiNx/PI substrates at room temperature (RT, 100 and 200 °C by radio frequency (RF magnetron sputtering. The thicknesses of the GZO and SiNx thin films were controlled at around 160 ± 12 nm and 150 ± 10 nm, respectively. The optimal deposition parameters for the SiNx thin films were a working pressure of 800 × 10−3 Torr, a deposition power of 20 W, a deposition temperature of 200 °C, and gas flowing rates of SiH4 = 20 sccm and NH3 = 210 sccm, respectively. For the GZO/PI and GZO-SiNx/PI structures we had found that the GZO thin films deposited at 100 and 200 °C had higher crystallinity, higher electron mobility, larger carrier concentration, smaller resistivity, and higher optical transmittance ratio. For that, the GZO thin films deposited at 100 and 200 °C on PI and SiNx/PI substrates with thickness of ~1000 nm were used to fabricate p-i-n hydrogenated amorphous silicon (α-Si thin film solar cells. 0.5% HCl solution was used to etch the surfaces of the GZO/PI and GZO-SiNx/PI substrates. Finally, PECVD system was used to deposit α-Si thin film onto the etched surfaces of the GZO/PI and GZO-SiNx/PI substrates to fabricate α-Si thin film solar cells, and the solar cells’ properties were also investigated. We had found that substrates to get the optimally solar cells’ efficiency were 200 °C-deposited GZO-SiNx/PI.

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

    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.

  16. Internal fuel pin oxidizer

    Andrews, M.G.

    1978-01-01

    A nuclear fuel pin has positioned within it material which will decompose to release an oxidizing agent which will react with the cladding of the pin and form a protective oxide film on the internal surface of the cladding

  17. Avalanche photodiodes for ISABELLE detectors

    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

  18. Substitution of photomultiplier tubes by photodiodes

    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)

  19. The photodiodes response in beta dosimetry

    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

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

    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.

  1. Photodiodes based on fullerene semiconductor

    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

  2. High-End Silicon PDICs

    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.

  3. Photodiodes utilization as ionizing radiation detectors

    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

  4. MICROCONTROLLER PIN CONFIGURATION TOOL

    Bhaskar Joshi; F. Mohammed Rizwan; Dr. Rajashree Shettar

    2012-01-01

    Configuring the micro controller with large number of pins is tedious. Latest Infine on microcontroller contains more than 200 pins and each pin has classes of signals. Therefore the complexity of the microcontroller is growing. It evolves looking into thousands of pages of user manual. For a user it will take days to configure the microcontroller with the peripherals. We need an automated tool to configure the microcontroller so that the user can configure the microcontroller without having ...

  5. Compact multispectral photodiode arrays using micropatterned dichroic filters

    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

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

    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.

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

    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

  8. High spatial resolution radiation detectors based on hydrogenated amorphous silicon and scintillator

    Jing, T.; Lawrence Berkeley Lab., CA

    1995-05-01

    Hydrogenated amorphous silicon (a-Si:H) as a large-area thin film semiconductor with ease of doping and low-cost fabrication capability has given a new impetus to the field of imaging sensors; its high radiation resistance also makes it a good material for radiation detectors. In addition, large-area microelectronics based on a-Si:H or polysilicon can be made with full integration of peripheral circuits, including readout switches and shift registers on the same substrate. Thin a-Si:H p-i-n photodiodes coupled to suitable scintillators are shown to be suitable for detecting charged particles, electrons, and X-rays. The response speed of CsI/a-Si:H diode combinations to individual particulate radiation is limited by the scintillation light decay since the charge collection time of the diode is very short (< 10ns). The reverse current of the detector is analyzed in term of contact injection, thermal generation, field enhanced emission (Poole-Frenkel effect), and edge leakage. A good collection efficiency for a diode is obtained by optimizing the p layer of the diode thickness and composition. The CsI(Tl) scintillator coupled to an a-Si:H photodiode detector shows a capability for detecting minimum ionizing particles with S/N ∼20. In such an arrangement a p-i-n diode is operated in a photovoltaic mode (reverse bias). In addition, a p-i-n diode can also work as a photoconductor under forward bias and produces a gain yield of 3--8 for shaping times of 1 micros. The mechanism of the formation of structured CsI scintillator layers is analyzed. Initial nucleation in the deposited layer is sensitive to the type of substrate medium, with imperfections generally catalyzing nucleation. Therefore, the microgeometry of a patterned substrate has a significant effect on the structure of the CsI growth

  9. High spatial resolution radiation detectors based on hydrogenated amorphous silicon and scintillator

    Jing, Tao [Univ. of California, Berkeley, CA (United States). Dept. of Engineering-Nuclear Engineering

    1995-05-01

    Hydrogenated amorphous silicon (a-Si:H) as a large-area thin film semiconductor with ease of doping and low-cost fabrication capability has given a new impetus to the field of imaging sensors; its high radiation resistance also makes it a good material for radiation detectors. In addition, large-area microelectronics based on a-Si:H or polysilicon can be made with full integration of peripheral circuits, including readout switches and shift registers on the same substrate. Thin a-Si:H p-i-n photodiodes coupled to suitable scintillators are shown to be suitable for detecting charged particles, electrons, and X-rays. The response speed of CsI/a-Si:H diode combinations to individual particulate radiation is limited by the scintillation light decay since the charge collection time of the diode is very short (< 10ns). The reverse current of the detector is analyzed in term of contact injection, thermal generation, field enhanced emission (Poole-Frenkel effect), and edge leakage. A good collection efficiency for a diode is obtained by optimizing the p layer of the diode thickness and composition. The CsI(Tl) scintillator coupled to an a-Si:H photodiode detector shows a capability for detecting minimum ionizing particles with S/N ~20. In such an arrangement a p-i-n diode is operated in a photovoltaic mode (reverse bias). In addition, a p-i-n diode can also work as a photoconductor under forward bias and produces a gain yield of 3--8 for shaping times of 1 {micro}s. The mechanism of the formation of structured CsI scintillator layers is analyzed. Initial nucleation in the deposited layer is sensitive to the type of substrate medium, with imperfections generally catalyzing nucleation. Therefore, the microgeometry of a patterned substrate has a significant effect on the structure of the CsI growth.

  10. Basic opto-electronics on silicon for sensor applications

    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.

  11. Enhancing the far-ultraviolet sensitivity of silicon complementary metal oxide semiconductor imaging arrays

    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.

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

    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.

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

    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. Light induced tunnel effect in CNT-Si photodiode

    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.

  15. A transimpedance amplifier for excess noise measurements of high junction capacitance avalanche photodiodes

    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)

  16. Study of PIN diode energy traps created by neutrons

    Sopko, V; Dammer, J; Sopko, B; Chren, D

    2013-01-01

    Characterization of radiation defects is still ongoing and finds greater application in the increasing radiation doses on semiconductor detectors in experiments. Studying the changes of silicon PIN diode for high doses of radiation is the fundamental motivation for our measurements. In this article we describe the behavior of the PIN diode and development of the disorder caused by neutrons from a 252Cf and doses up to 8 Gy. The calibration curve for PIN diode shows the effect of disorders as the changes of the voltampere characteristics depending on the dose of neutron irradiation. The measured values for defects are in good agreement with created energy traps.

  17. PINS Spectrum Identification Guide

    A.J. Caffrey

    2012-03-01

    The Portable Isotopic Neutron Spectroscopy—PINS, for short—system identifies the chemicals inside munitions and containers without opening them, a decided safety advantage if the fill chemical is a hazardous substance like a chemical warfare agent or an explosive. The PINS Spectrum Identification Guide is intended as a reference for technical professionals responsible for the interpretation of PINS gamma-ray spectra. The guide is divided into two parts. The three chapters that constitute Part I cover the science and technology of PINS. Neutron activation analysis is the focus of Chapter 1. Chapter 2 explores PINS hardware, software, and related operational issues. Gamma-ray spectral analysis basics are introduced in Chapter 3. The six chapters of Part II cover the identification of PINS spectra in detail. Like the PINS decision tree logic, these chapters are organized by chemical element: phosphorus-based chemicals, chlorine-based chemicals, etc. These descriptions of hazardous, toxic, and/or explosive chemicals conclude with a chapter on the identification of the inert chemicals, e.g. sand, used to fill practice munitions.

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

    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.

  19. Fuel pin transfer tool

    Patenaude, R. S.

    1985-01-01

    A fuel pin transfer tool has a latching device of the collet type attached to a first member movable vertically through a long work stroke enabling a fuel pin in an under water assembly to be engaged and withdrawn therefrom or placed therein and released. The latching device has a collet provided with a plurality of resilient fingers having cam portions normally spaced apart to receive the upper end of a fuel pin between them and a second member, movable vertically through a short stroke relative to the first member is provided with cam portions engageable with those of the fingers and is yieldably and resiliently held in a raised position in which its cam portions engage those of the fingers and force the fingers into their pin-gripping positions. When a predetermined force is applied to the second member, it is so moved that its cam portions are disengaged from the cam portions of the fingers permitting the latter to move into their normal relationship in which a gripped pin is released or another pin received but with their pin-gripping relationship positively re-established and maintained once the force on the tubular member is lessened. Movement of the first member in either direction and movement of the second member into its raised position is attended by forces inadequate to affect the integrity of fuel pin cladding. That force is applied in the preferred embodiment, by a power operated actuator which is within the upper portion of a housing and, in the preferred embodiment, carried by the long stroke member but always in the upper housing portion which is of a material sufficiently translucent to enable the actuator to be observed throughout the work stroke and is sufficiently light in weight to prevent the tool from being top heavy

  20. Photodiode measurements in Nucte-II

    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

  1. Flux Pinning in Superconductors

    Matsushita, Teruo

    2007-01-01

    The book covers the flux pinning mechanisms and properties and the electromagnetic phenomena caused by the flux pinning common for metallic, high-Tc and MgB2 superconductors. The condensation energy interaction known for normal precipitates or grain boundaries and the kinetic energy interaction proposed for artificial Nb pins in Nb-Ti, etc., are introduced for the pinning mechanism. Summation theories to derive the critical current density are discussed in detail. Irreversible magnetization and AC loss caused by the flux pinning are also discussed. The loss originally stems from the ohmic dissipation of normal electrons in the normal core driven by the electric field induced by the flux motion. The readers will learn why the resultant loss is of hysteresis type in spite of such mechanism. The influence of the flux pinning on the vortex phase diagram in high Tc superconductors is discussed, and the dependencies of the irreversibility field are also described on other quantities such as anisotropy of supercondu...

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

    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

  3. Accelerated aging tests of radiation damaged lasers and photodiodes for the CMS tracker optical links

    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).

  4. Hybrid amplifier for calorimetry with photodiode readout

    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.

  5. Dose determination on buildup region using photodiodes

    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

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

    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.

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

    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.

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

    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

  9. Determination of the excess noise of avalanche photodiodes integrated in 0.35-μm CMOS technologies

    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.

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

    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

  11. Sensitive pre-amplifier to load for Pin diodes

    Jacobo V, R. Y.; Hernandez D, V.; Ramirez J, F. J.

    2013-10-01

    The electronic instrumentation is indispensable for the measurement and characterization of the radiation. By means of this essential characteristics of the radiation are determined, as activity and their energy components. The nuclear instrumentation is based on the technical characteristics of the radiation detectors and the electronic devices associates (amplifiers, ana logical and digital converters, multichannel analyzers, etc.) The radiation detectors are very important instruments in fields as the nuclear physics, medicine, radiological protection, industry and in other fields, since they are the only method to capture the radiation and to be able to quantify it in precise form. To detect radiation diverse detector types are used, as the semiconductor type, inside them are the photodiodes type Pin. In this work the results that were obtained of the design, simulation, construction and tests of a preamplifier that was designed starting from a photodiode type Pin are presented. The system was designed and simulated with a program for electronic circuits, in this were carried out many tests being obtained a compact design and achieving the best necessary characteristics for its optimization. With the results of the simulation phase the electronics phase was built, which was couples to a spectroscopic amplifier and a multichannel analyzer. The total of the system was evaluated analyzing its performance before a triple source of alphas. Of the tests phase we find that the system allows obtaining, in a multichannel analyzer, the pulses height spectrum, with a good resolution and with this was calibrated the multichannel analyzer

  12. Modeling charge collection efficiency degradation in partially depleted GaAs photodiodes using the 1- and 2-carrier Hecht equations

    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.

  13. Modeling charge collection efficiency degradation in partially depleted GaAs photodiodes using the 1- and 2-carrier Hecht equations

    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.

  14. PINS-3X Operations

    E.H. Seabury

    2013-09-01

    Idaho National Laboratory’s (INL’s) Portable Isotopic Neutron Spectroscopy System (PINS) non-intrusively identifies the chemical fill of munitions and sealed containers. The PINS-3X variant of the system is used to identify explosives and uses a deuterium-tritium (DT) electronic neutron generator (ENG) as the neutron source. Use of the system, including possession and use of the neutron generator and shipment of the system components requires compliance with a number of regulations. This report outlines some of these requirements as well as some of the requirements in using the system outside of INL.

  15. Characteristics of fabricated si PIN-type radiation detectors on cooling temperature

    Kim, Han Soo; Jeong, Manhee; Kim, Young Soo [Korea Atomic Energy Research Institute, Jeongeup-si 580-185 (Korea, Republic of); Lee, Dong Hun [Korea Research Institute of Standards and Science, Daejeon 305-340 (Korea, Republic of); Cho, Seung Yeon [Environmental Health Center, Yonsei University, Wonju-si 1184-4 (Korea, Republic of); Ha, Jang Ho [Korea Atomic Energy Research Institute, Jeongeup-si 580-185 (Korea, Republic of)

    2015-06-01

    Si PIN photodiode radiation detectors with three different active areas (3×3 mm{sup 2}, 5×5 mm{sup 2}, and 10×10 mm{sup 2}) were designed and fabricated at the Korea Atomic Energy Research Institute (KAERI) for low energy X- and gamma-ray detection. In Si-based semiconductor radiation detectors, one of the noise sources is thermal noise, which degrades their energy resolution performance. In this study, the temperature effects on the energy resolution were investigated using a 3×3 mm{sup 2} active area PIN photodiode radiation detector using a Thermoelectric Module (TEM) from room temperature to −23 °C. Energy resolutions from 25 keV auger electrons to 81 keV gamma-ray from a Ba-133 calibration source were measured and compared at every 10 °C interval. At −23 °C, energy resolutions were improved by 15.6% at 25 keV, 4.0% at 31 keV, and 1.2% at 81 keV in comparison with resolutions at room temperature. CsI(Tl)/PIN photodiode radiation detectors were also fabricated for relatively high energy gamma-ray detection. Energy resolutions for Cs-137, Co-60, and Na-22 sources were measured and compared with the spectral responsivity.

  16. Sensitive pre-amplifier to load for Pin diodes; Pre-amplificador sensible a carga para diodos PIN

    Jacobo V, R. Y.; Hernandez D, V. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98060 Zacatecas (Mexico); Ramirez J, F. J., E-mail: yoshimarv@gmail.com [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2013-10-15

    The electronic instrumentation is indispensable for the measurement and characterization of the radiation. By means of this essential characteristics of the radiation are determined, as activity and their energy components. The nuclear instrumentation is based on the technical characteristics of the radiation detectors and the electronic devices associates (amplifiers, ana logical and digital converters, multichannel analyzers, etc.) The radiation detectors are very important instruments in fields as the nuclear physics, medicine, radiological protection, industry and in other fields, since they are the only method to capture the radiation and to be able to quantify it in precise form. To detect radiation diverse detector types are used, as the semiconductor type, inside them are the photodiodes type Pin. In this work the results that were obtained of the design, simulation, construction and tests of a preamplifier that was designed starting from a photodiode type Pin are presented. The system was designed and simulated with a program for electronic circuits, in this were carried out many tests being obtained a compact design and achieving the best necessary characteristics for its optimization. With the results of the simulation phase the electronics phase was built, which was couples to a spectroscopic amplifier and a multichannel analyzer. The total of the system was evaluated analyzing its performance before a triple source of alphas. Of the tests phase we find that the system allows obtaining, in a multichannel analyzer, the pulses height spectrum, with a good resolution and with this was calibrated the multichannel analyzer.

  17. Silicon photonics fundamentals and devices

    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 ...

  18. Pinning Down versus Density

    Juhász, István; Soukup, Lajos; Szentmiklóssy, Zoltán

    2015-01-01

    The pinning down number $ {pd}(X)$ of a topological space $X$ is the smallest cardinal $\\kappa$ such that for any neighborhood assignment $U:X\\to \\tau_X$ there is a set $A\\in [X]^\\kappa$ with $A\\cap U(x)\

  19. Pin clad strains in Phenix

    Languille, A.

    1979-07-01

    The Phenix reactor has operated for 4 years in a satisfactory manner. The first 2 sub-assembly loadings contained pins clad in solution treated 316. The principal pin strains are: diametral strain (swelling and irradiation creep), ovality and spiral bending of the pin (interaction of wire and pin cluster and wrapper). A pin cluster irradiated to a dose of 80 dpa F reached a pin diameter strain of 5%. This strain is principally due to swelling (low fission gas pressure). The principal parameters governing the swelling are instantaneous dose, time and temperature for a given type of pin cladding. Other types of steel are or will be irradiated in Phenix. In particular, cold-worked titanium stabilised 316 steel should contribute towards a reduction in the pin clad strains and increase the target burn-up in this reactor. (author)

  20. Radiation monitoring with CVD diamonds and PIN diodes at BaBar

    Bruinsma, M. [University of California Irvine, Irvine, CA 92697 (United States); Burchat, P. [Stanford University, Stanford, CA 94305-4060 (United States); Curry, S. [University of California Irvine, Irvine, CA 92697 (United States)], E-mail: scurry@slac.stanford.edu; Edwards, A.J. [Stanford University, Stanford, CA 94305-4060 (United States); Kagan, H.; Kass, R. [Ohio State University, Columbus, OH 43210 (United States); Kirkby, D. [University of California Irvine, Irvine, CA 92697 (United States); Majewski, S.; Petersen, B.A. [Stanford University, Stanford, CA 94305-4060 (United States)

    2007-12-11

    The BaBar experiment at the Stanford Linear Accelerator Center has been using two polycrystalline chemical vapor deposition (pCVD) diamonds and 12 silicon PIN diodes for radiation monitoring and protection of the Silicon Vertex Tracker (SVT). We have used the pCVD diamonds for more than 3 years, and the PIN diodes for 7 years. We will describe the SVT and SVT radiation monitoring system as well as the operational difficulties and radiation damage effects on the PIN diodes and pCVD diamonds in a high-energy physics environment.

  1. Pentacene-based photodiode with Schottky junction

    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

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

    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.)

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

    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).

  4. Nuclear fuel pin

    Hartley, Kenneth; Moulding, T.L.J.; Rostron, Norman.

    1979-01-01

    Fuel pin for use in fast breeder nuclear reactors containing fissile and fertile areas of which the fissile and fertile materials do not mix. The fissile material takes the shape of large and small diameter microspheres (the small diameter microspheres can pass through the interstices between the large microspheres). The barrier layers being composed of microspheres with a diameter situated between those of the large and small microspheres ensure that the materials do not mix [fr

  5. Pinning in nonmagnetic borocarbides

    Zholobenko, A.N.; Mikitik, G.P.; Fil, V.D.; Kim, J.D.; Lee, S.I.

    2005-01-01

    The field dependences of the Labush parameter in nonmagnetic borocarbides are measured by the method which does not require the free flux flow regime. The anticipated critical current densities are estimated. These values are by two orders of magnitude higher than those measured 'directly' in transport (magnetic) experiments. The giant peak-effect in the field dependences of the Labush parameter is revealed in the Y-based borocarbides. Its behavior is well approximated by the collective pinning theory

  6. Optimization of Packaging for PIN Photodiode Modules for 100Gbit/s Ethernet Applications

    Jiang, Chenhui; Johansen, Tom Keinicke; Krozer, Viktor

    2007-01-01

    In this paper the packaging of optical components is investigated employing a conductor backed coplanar waveguide (CBCPW). The study is performed using 3D electromagnetic (EM) simulations in a broadband range up to 110GHz. Higher-order resonances are observed in both measurement and simulation...... results. Based on the verified EM simulation setup, the origin of resonances is identified and remedies are suggested in the paper. Several optimization schemes for achieving good transmission characteristics for the planar structure as well as for the coax-CPW transition are proposed such as properly...

  7. Liquid-helium scintillation detection with germanium photodiodes

    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

  8. Radiation damage effect on avalanche photodiodes

    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.

  9. Responses of the multi-photodiode readout

    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

  10. Compact silicon photonics-based multi laser module for sensing

    Ayotte, S.; Costin, F.; Babin, A.; Paré-Olivier, G.; Morin, M.; Filion, B.; Bédard, K.; Chrétien, P.; Bilodeau, G.; Girard-Deschênes, E.; Perron, L.-P.; Davidson, C.-A.; D'Amato, D.; Laplante, M.; Blanchet-Létourneau, J.

    2018-02-01

    A compact three-laser source for optical sensing is presented. It is based on a low-noise implementation of the Pound Drever-Hall method and comprises high-bandwidth optical phase-locked loops. The outputs from three semiconductor distributed feedback lasers, mounted on thermo-electric coolers (TEC), are coupled with micro-lenses into a silicon photonics (SiP) chip that performs beat note detection and several other functions. The chip comprises phase modulators, variable optical attenuators, multi-mode-interference couplers, variable ratio tap couplers, integrated photodiodes and optical fiber butt-couplers. Electrical connections between a metallized ceramic and the TECs, lasers and SiP chip are achieved by wirebonds. All these components stand within a 35 mm by 35 mm package which is interfaced with 90 electrical pins and two fiber pigtails. One pigtail carries the signals from a master and slave lasers, while another carries that from a second slave laser. The pins are soldered to a printed circuit board featuring a micro-processor that controls and monitors the system to ensure stable operation over fluctuating environmental conditions. This highly adaptable multi-laser source can address various sensing applications requiring the tracking of up to three narrow spectral features with a high bandwidth. It is used to sense a fiber-based ring resonator emulating a resonant fiber optics gyroscope. The master laser is locked to the resonator with a loop bandwidth greater than 1 MHz. The slave lasers are offset frequency locked to the master laser with loop bandwidths greater than 100 MHz. This high performance source is compact, automated, robust, and remains locked for days.

  11. Amorphous silicon based radiation detectors

    Perez-Mendez, V.; Cho, G.; Drewery, J.; Jing, T.; Kaplan, S.N.; Qureshi, S.; Wildermuth, D.; Fujieda, I.; Street, R.A.

    1991-07-01

    We describe the characteristics of thin(1 μm) and thick (>30μm) hydrogenated amorphous silicon p-i-n diodes which are optimized for detecting and recording the spatial distribution of charged particles, x-rays and γ rays. For x-ray, γ ray, and charged particle detection we can use thin p-i-n photosensitive diode arrays coupled to evaporated layers of suitable scintillators. For direct detection of charged particles with high resistance to radiation damage, we use the thick p-i-n diode arrays. 13 refs., 7 figs

  12. Switching characteristic and capacitance analysis of a-Si:H pinpin photodiodes for visible range telecommunications

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

    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)

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

    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)

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

    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.

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

    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

  17. Transformation of Helicopter PinS Procedures for Airplanes

    Jakub Kraus

    2013-09-01

    Full Text Available This article deals with the possibility to use existing helicopter Point in Space procedures with minor changes for airplanes. The basis is to find parts of PinS procedures that need to be changed, suggest these changes, and then determine whether the revised procedures could be usable and could bring the benefits for airplane operations.

  18. Pinning, de-pinning and re-pinning of a slowly varying rivulet

    Paterson, C.; Wilson, S.K.; Duffy, B.R.

    2013-01-01

    The solutions for the unidirectional flow of a thin rivulet with prescribed volume flux down an inclined planar substrate are used to describe the locally unidirectional flow of a rivulet with constant width (i.e. pinned contact lines) but slowly varying contact angle as well as the possible pinning and subsequent de-pinning of a rivulet with constant contact angle and the possible de-pinning and subsequent re-pinning of a rivulet with constant width as they flow in the azimuthal direction from the top to the bottom of a large horizontal cylinder. Despite being the same locally, the global behaviour of a rivulet with constant width can be very different from that of a rivulet with constant contact angle. In particular, while a rivulet with constant non-zero contact angle can always run from the top to the bottom of the cylinder, the behaviour of a rivulet with constant width depends on the value of the width. Specifically, while a narrow rivulet can run all the way from the top to the bottom of the cylinder, a wide rivulet can run from the top of the cylinder only to a critical azimuthal angle. The scenario in which the hitherto pinned contact lines of the rivulet de-pin at the critical azimuthal angle and the rivulet runs from the critical azimuthal angle to the bottom of the cylinder with zero contact angle but slowly varying width is discussed. The pinning and de-pinning of a rivulet with constant contact angle, and the corresponding situation involving the de-pinning and re-pinning of a rivulet with constant width at a non-zero contact angle which generalises the de-pinning at zero contact angle discussed earlier, are described. In the latter situation, the mass of fluid on the cylinder is found to be a monotonically increasing function of the constant width. © 2013 Elsevier Masson SAS. All rights reserved.

  19. Pinning, de-pinning and re-pinning of a slowly varying rivulet

    Paterson, C.

    2013-09-01

    The solutions for the unidirectional flow of a thin rivulet with prescribed volume flux down an inclined planar substrate are used to describe the locally unidirectional flow of a rivulet with constant width (i.e. pinned contact lines) but slowly varying contact angle as well as the possible pinning and subsequent de-pinning of a rivulet with constant contact angle and the possible de-pinning and subsequent re-pinning of a rivulet with constant width as they flow in the azimuthal direction from the top to the bottom of a large horizontal cylinder. Despite being the same locally, the global behaviour of a rivulet with constant width can be very different from that of a rivulet with constant contact angle. In particular, while a rivulet with constant non-zero contact angle can always run from the top to the bottom of the cylinder, the behaviour of a rivulet with constant width depends on the value of the width. Specifically, while a narrow rivulet can run all the way from the top to the bottom of the cylinder, a wide rivulet can run from the top of the cylinder only to a critical azimuthal angle. The scenario in which the hitherto pinned contact lines of the rivulet de-pin at the critical azimuthal angle and the rivulet runs from the critical azimuthal angle to the bottom of the cylinder with zero contact angle but slowly varying width is discussed. The pinning and de-pinning of a rivulet with constant contact angle, and the corresponding situation involving the de-pinning and re-pinning of a rivulet with constant width at a non-zero contact angle which generalises the de-pinning at zero contact angle discussed earlier, are described. In the latter situation, the mass of fluid on the cylinder is found to be a monotonically increasing function of the constant width. © 2013 Elsevier Masson SAS. All rights reserved.

  20. Study of the Radiation-Hardness of VCSEL and PIN

    Gan, K K; Fernando, W; Kagan, H P; Kass, R D; Lebbai, M R M; Merritt, H; Moore, J R; Nagarkar, A; Rizatdinova, F; Skubic, P L; Smith, D S; Strang, M

    2009-01-01

    The silicon trackers of the ATLAS experiment at the Large Hadron Collider (LHC) at CERN (Geneva) use optical links for data transmission. An upgrade of the trackers is planned for the Super LHC (SLHC), an upgraded LHC with ten times higher luminosity. We study the radiation-hardness of VCSELs (Vertical-Cavity Surface-Emitting Laser) and GaAs and silicon PINs using 24 GeV/c protons at CERN for possible application in the data transmission upgrade. The optical power of VCSEL arrays decreases significantly after the irradiation but can be partially annealed with high drive currents. The responsivities of the PIN diodes also decrease significantly after irradiation, but can be recovered by operating at higher bias voltage. This provides a simple mechanism to recover from the radiation damage.

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

    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...

  2. Ge/Si (100) heterojunction photodiodes fabricated from material grown by low-energy plasma-enhanced chemical vapour deposition

    Osmond, Johann; Isella, Giovanni; Chrastina, Daniel; Kaufmann, Rolf; Kaenel, Hans von

    2008-01-01

    We have fabricated a series of p-i-n Ge/Si heterojunction photodetectors with different thicknesses of the intrinsic Ge layer, different doping levels of the p and n layers and different diode diameters. Epitaxial Ge was deposited on Si(100) using low-energy plasma-enhanced CVD (LEPECVD) followed by cyclic annealing. Dark current values as low as 0.04 mA/cm 2 were achieved for 1 μm thick p-i-n photodiodes on lightly doped substrates at - 1 V bias, and external quantum efficiencies of 56% at 1.30 μm and 44% at 1.55 μm for 3 μm thick p + -i-n + photodiodes on highly doped substrates under 0.5 V reverse bias. For a 30 μm diameter diode a RC frequency of 21 GHz is obtained at a reverse bias of 1 V. With such characteristics, these diodes are attractive for telecommunication and optoelectronic applications

  3. Vortex pinning and creep experiments

    Kes, P.H.

    1991-01-01

    A brief review of basic flux-pinning and flux-creep ingredients and a selection of experimental results on high-temperature-superconductivity compounds is presented. Emphasis is put on recent results and on those properties which are central to the emerging understanding of the flux-pinning and flux-creep mechanisms of these fascinating materials

  4. Diamond photodiodes for x-ray application

    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.

  5. Photodiode read-out of the ALICE photon spectrometer $PbWO_{4}$ crystals

    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...

  6. Spiral silicon drift detectors

    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

  7. Automated fuel pin loading system

    Christiansen, D.W.; Brown, W.F.; Steffen, J.M.

    An automated loading system for nuclear reactor fuel elements utilizes a gravity feed conveyor which permits individual fuel pins to roll along a constrained path perpendicular to their respective lengths. The individual lengths of fuel cladding are directed onto movable transports, where they are aligned coaxially with the axes of associated handling equipment at appropriate production stations. Each fuel pin can be be reciprocated axially and/or rotated about its axis as required during handling steps. The fuel pins are inerted as a batch prior to welding of end caps by one of two disclosed welding systems.

  8. Pinning down the axion

    Dabholkar, A.; Quashnock, J.M.

    1990-01-01

    Davis has argued that, without inflation, the decay of axionic strings is the primary source of axions. This implies a cosmological lower bound on the axion mass of 10 -5 to 10 -3 eV. In order to obtain a sharper bound it is essential to know the spectrum of emitted axions and the detailed motion of a global string strongly coupled to the axionic field. To this end, we obtain self-consistent, renormalized equations that describe the dynamics of a radiating global string interacting with its surrounding axionic field. We describe the numerical formalism for evolving string trajectories using these equations. From the numerical and analytical evidence we argue that, with appropriate renormalization, the motion of an interacting cosmic string loop can be well approximated by the motion of a free Nambu-Goto string. This implies a lower bound for the axion mass of 10 -3 eV. Together with the recent upper bound of 4x10 -4 eV from the supernova SN1987a, this marginally rules out the invisible axion, or at least pins down the axion mass to a very narrow window around 10 -3 eV. This still leaves open the window around 2 eV for hardronic axions, but in that case the axion is no longer a serious dark matter candidate. (orig.)

  9. Microtextured Silicon Surfaces for Detectors, Sensors & Photovoltaics

    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.

  10. Large area avalanche MRS-photodiodes for nuclear spectroscopy

    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.

  11. Pinning Mechanisms in YBCO Tapes

    Spera, Marcello; Ballarino, Amalia

    2015-01-01

    In this thesis work, a study on flux pinning mechanisms of commercial YBCO tapes is presented. This study has been performed via critical current characterization using transport (via direct I-V curves) and magnetization (via a Vibrating Sample Magnetometer) measurements. The latter ones turned out to be better concerning the comprehension of the pinning landscape of the provided samples, as a wider range of magnetic fields and temperatures is available for those measurements in the setup I used. The comparison of the experimental data with existing theoretical models allowed me to draw a picture of the pinning mechanisms underlying in each sample, and they turned out to be quite different one another. Moreover, for high-performance research tapes, another interesting feature has been found: the counterplay between the self-field critical current and the in-field one. Very well engineered artificial pinning structures limit the self-field critical current density due to the hi...

  12. Geiger mode avalanche photodiodes for microarray systems

    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.

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

    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)

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

    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.)

  15. Automated system for loading nuclear fuel pins

    Marshall, J.L.

    1983-10-01

    A completely automatic and remotely controlled fuel pin fabrication system is being designed by the Westinghouse Hanford Company. The Pin Operations System will produce fuel pins for the Fast Flux Test Facility (FFTF) and the Clinch River Breeder Reactor Plant (CRBRP). The system will assemble fuel pin components into cladding tubes in a controlled environment. After fuel loading, the pins are filled with helium, the tag gas capsules are inserted, and the top end cap welded. Following welding, the pins are surveyed to assure they are free of contamination and then the pins are helium leak tested

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

    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.

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

    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.

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

    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.

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

    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.

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

    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

  1. First results of systematic studies done with silicon photomultipliers

    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).

  2. Micro benchtop optics by bulk silicon micromachining

    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.

  3. Enhanced pinning in superconducting thin films with graded pinning landscapes

    Motta, M.; Colauto, F.; Ortiz, W. A.; Fritzsche, J.; Cuppens, J.; Gillijns, W.; Moshchalkov, V. V.; Johansen, T. H.; Sanchez, A.; Silhanek, A. V.

    2013-05-01

    A graded distribution of antidots in superconducting a-Mo79Ge21 thin films has been investigated by magnetization and magneto-optical imaging measurements. The pinning landscape has maximum density at the sample border, decreasing linearly towards the center. Its overall performance is noticeably superior than that for a sample with uniformly distributed antidots: For high temperatures and low fields, the critical current is enhanced, whereas the region of thermomagnetic instabilities in the field-temperature diagram is significantly suppressed. These findings confirm the relevance of graded landscapes on the enhancement of pinning efficiency, as recently predicted by Misko and Nori [Phys. Rev. B 85, 184506 (2012)].

  4. Characterization of new hexagonal large area Geiger Avalanche Photodiodes

    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

  5. Stress relaxation of thermally bowed fuel pins

    Crossland, I.G.; Speight, M.V.

    1983-01-01

    The presence of cross-pin temperature gradients in nuclear reactor fuel pins produces differential thermal expansion which, in turn, causes the fuel pin to bow elastically. If the pin is restrained in any way, such thermal bowing causes the pin to be stressed. At high temperatures these stresses can relax by creep and it is shown here that this causes the pin to suffer an additional permanent deflection, so that when the cross-pin temperature difference is removed the pin remains bowed. By representing the cylindrical pin by an equivalent I-beam, the present work examines this effect when it takes place by secondary creep. Two restraint systems are considered, and it is demonstrated that the rate of relaxation depends mainly upon the creep equation, and hence the temperature, and also the magnitude of the initial stresses. (author)

  6. Defect pin behaviour in the DFR

    Sloss, W.M.; Bagley, K.Q.; Edmonds, E.; Potter, P.E.

    1979-01-01

    A program of defective fuel pin irradiations has been carried out in the DFR. This program employed fuel pins which had failed during previous irradiations (natural defects) and pins in which simulated failures (artificial defects) had been induced prior to irradiation or during an intermediate examination stage at moderate or substantial burnups. The artificial defects simulated longitudinal ruptures and were normally located at positions near the top, middle and bottom of the pin where clad temperatures were 450, 540 and 630 0 C respectively. The fuel was mixed U-Pu oxide, and fuel form, stoichiometry, clad type, pin diameter, linear rating, and burnup were among the variables examined. The defect pin tests were normally carried out in single pin or trefoil type vehicles. After irradiation all the pins were subjected to the normal nondestructive examination procedures and the visual, radiographic, gamma-scanning, and dimensional change results are presented. Several pins were destructively examined and the metallographic data are discussed

  7. MONJU fuel pin performance analysis

    Kitagawa, H.; Yamanaka, T.; Hayashi, H.

    1979-01-01

    Monju fuel pin has almost the same properties as other LMFBR fuel pins, i.e. Phenix, PFR, CRBR, but would be irradiated under severe conditions: maximum linear heat rate of 381 watt/cm, hot spot cladding temperature of 675 deg C, peak burnup of 131,000 MWd/t, peak fluence (E greater than 0.1 MeV) of 2.3 10 23 n/cm 2 . In order to understand in-core performance of Monju fuel pin, its thermal and mechanical behaviour was predicted using the fast running performance code SIMPLE. The code takes into account pellet-cladding interaction due to thermal expansion and swelling, gap conductance, structural changes of fuel pellets, fission product gas release with burnup and temperature increase, swelling and creep of fuel pellets, corrosion of cladding due to sodium flow and chemical attack by fission products, and cumulative damage of the cladding due to thermal creep

  8. Neutron radiography of fuel pins

    Jackson, C.N. Jr.; Powers, H.G.; Burgess, C.A.

    1975-01-01

    Neutron radiography performed with a reactor source has been shown to be a superior radiographic method for the examination of unirradiated mixed oxide fuel pins at the Hanford Engineering Development Laboratory. Approximately 1,700 fuel pins were contained in a sample that demonstrated the capability of the method for detecting laminations, structural flaws, fissile density variation, hydrogenous inclusions and voids in assembled fuel pins. The nature, extent, and importance of the detected conditions are substantiated by gamma autoradiography and by destructive analysis employing alpha autoradiography, electron microprobe and visual inspection. Also, a series of radiographs illustrate the response of neutron radiography as compared to low voltage and high voltage x-ray and gamma source Iridium 192 radiography. (U.S.)

  9. Mode of failure of LMFBR fuel pins

    Washburn, D.F.

    1975-01-01

    The objectives of the irradiation test described were to evaluate mixed-oxide fuel performance and to confirm the design adequacy of the FFTF fuel pins. After attainment of the initial objectives the irradiation of several of the original fuel pins was continued until a cladding breach occurred. The consequences of a cladding breach were evaluated by reconstituting the original 37-pin subassembly into two 19-pin subassemblies after a burnup at 50,000 MWd/MTM (5.2 a/o). The original pins were supplemented with fresh pins as necessary. Irradiation of the subassemblies was continued until a cladding breach occurred. Results are presented and discussed

  10. Improved charge collection of the buried p-i-n a-Si:H radiation detectors

    Fujieda, I.; Cho, G.; Conti, M.; Drewery, J.; Kaplan, S.N.; Perez-Mendez, V.; Qureshi, S.; Street, R.A.

    1989-09-01

    Charge collection in hydrogenated amorphous silicon (a-Si:H) radiation detectors is improved for high LET particle detection by adding thin intrinsic layers to the usual p-i-n structure. This buried p-i-n structure enables us to apply higher bias and the electric field is enhanced. When irradiated by 5.8 MeV α particles, the 5.7 μm thick buried p-i-n detector with bias 300V gives a signal size of 60,000 electrons, compared to about 20,000 electrons with the simple p-i-n detectors. The improved charge collection in the new structure is discussed. The capability of tailoring the field profile by doping a-Si:H opens a way to some interesting device structures. 17 refs., 7 figs

  11. Discussion about photodiode architectures for space applications

    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.

  12. Improved pinning regime by energetic ions using reduction of pinning potential

    Weinstein, Roy; Gandini, Alberto; Sawh, Ravi-Persad; Parks, Drew; Mayes, Bill

    2003-05-15

    When ion damage is used to create pinning centers, full columnar pinning centers provide the largest pinning potential, U{sub pin}, but not the greatest J{sub c} or pinned field, B{sub pin}. Some of the characteristics of columnar defects which limit J{sub c} and B{sub pin} are discussed, including reduction of percolation path, and the need for a larger number of columns of damage, for pinning, than are usually estimated. It is concluded that columnar pinning centers are limited to B{sub pin}<4 T, and also severely reduce J{sub c}. Evidence is reviewed that aligned damage, or broken-columnar pinning centers, described herein, can provide orders of magnitude higher J{sub c}, and higher pinned field, despite providing lower U{sub pin}. A pinning center morphology is discussed which utilizes multiple-in-line-damage (MILD). For, e.g., present day large grain HTS J{sub c}, obtainable by MILD pinning, is estimated to be of the order of 10{sup 6} A/cm{sup 2} at 77 K, even when crystal plane alignment and weak links are not improved. Pinned field is increased by over an order of magnitude. An experiment is proposed to confirm these observations, and to directly compare MILD to columnar pinning centers. It will also determine the optimum MILD structure. Other measurements of interest, made possible by the same data set, are described.

  13. A compact, discrete CsI(Tl) scintillator/Si photodiode gamma camera for breast cancer imaging

    Gruber, Gregory J. [Univ. of California, Berkeley, CA (United States)

    2000-01-01

    Recent clinical evaluations of scintimammography (radionuclide breast imaging) are promising and suggest that this modality may prove a valuable complement to X-ray mammography and traditional breast cancer detection and diagnosis techniques. Scintimammography, however, typically has difficulty revealing tumors that are less than 1 cm in diameter, are located in the medial part of the breast, or are located in the axillary nodes. These shortcomings may in part be due to the use of large, conventional Anger cameras not optimized for breast imaging. In this thesis I present compact single photon camera technology designed specifically for scintimammography which strives to alleviate some of these limitations by allowing better and closer access to sites of possible breast tumors. Specific applications are outlined. The design is modular, thus a camera of the desired size and geometry can be constructed from an array (or arrays) of individual modules and a parallel hole lead collimator for directional information. Each module consists of: (1) an array of 64 discrete, optically-isolated CsI(Tl) scintillator crystals 3 x 3 x 5 mm3 in size, (2) an array of 64 low-noise Si PIN photodiodes matched 1-to-1 to the scintillator crystals, (3) an application-specific integrated circuit (ASIC) that amplifies the 64 photodiode signals and selects the signal with the largest amplitude, and (4) connectors and hardware for interfacing the module with a motherboard, thereby allowing straightforward computer control of all individual modules within a camera.

  14. A compact, discrete CsI(Tl) scintillator/Si photodiode gamma camera for breast cancer imaging

    Gruber, Gregory J.

    2000-01-01

    Recent clinical evaluations of scintimammography (radionuclide breast imaging) are promising and suggest that this modality may prove a valuable complement to X-ray mammography and traditional breast cancer detection and diagnosis techniques. Scintimammography, however, typically has difficulty revealing tumors that are less than 1 cm in diameter, are located in the medial part of the breast, or are located in the axillary nodes. These shortcomings may in part be due to the use of large, conventional Anger cameras not optimized for breast imaging. In this thesis I present compact single photon camera technology designed specifically for scintimammography which strives to alleviate some of these limitations by allowing better and closer access to sites of possible breast tumors. Specific applications are outlined. The design is modular, thus a camera of the desired size and geometry can be constructed from an array (or arrays) of individual modules and a parallel hole lead collimator for directional information. Each module consists of: (1) an array of 64 discrete, optically-isolated CsI(Tl) scintillator crystals 3 x 3 x 5 mm 3 in size, (2) an array of 64 low-noise Si PIN photodiodes matched 1-to-1 to the scintillator crystals, (3) an application-specific integrated circuit (ASIC) that amplifies the 64 photodiode signals and selects the signal with the largest amplitude, and (4) connectors and hardware for interfacing the module with a motherboard, thereby allowing straightforward computer control of all individual modules within a camera

  15. Multicenter Study of Pin Site Infections and Skin Complications Following Pinning of Pediatric Supracondylar Humerus Fractures.

    Combs, Kristen; Frick, Steven; Kiebzak, Gary

    2016-12-03

    Pediatric supracondylar humerus fractures are the most common elbow fractures in pediatric patients. Surgical fixation using pins is the primary treatment for displaced fractures. Pin site infections may follow supracondylar humerus fracture fixation; the previously reported incidence rate in the literature is 2.34%, but there is significant variability in reported incidence rates of pin site infection. This study aims to define the incidence rate and determine pre-, peri-, and postoperative factors that may contribute to pin site infection following operative reduction, pinning, and casting. A retrospective chart analysis was performed over a one-year period on patients that developed pin site infection. A cast care form was added to Nemours' electronic medical records (EMR) system (Epic Systems Corp., Verona, WI) to identify pin site infections for retrospective review. The cast care form noted any inflamed or infected pins. Patients with inflamed or infected pin sites underwent a detailed chart review. Preoperative antibiotic use, number and size of pins used, method of postoperative immobilization, pin dressings, whether postoperative immobilization was changed prior to pin removal, and length of time pins were in place was recorded. A total of 369 patients underwent operative reduction, pinning, and casting. Three patients developed a pin site infection. The pin site infection incidence rate was 3/369=0.81%. Descriptive statistics were reported for the three patients that developed pin site infections and three patients that developed pin site complications. Pin site infection development is low. Factors that may contribute to the development of pin site infection include preoperative antibiotic use, length of time pins are left in, and changing the cast prior to pin removal.

  16. Fuel pin bowing in CAGR

    Crossland, I.G.

    1982-01-01

    Some of the more important mechanisms by which pin bowing can occur in Advanced Gas Cooled Reactors are examined. These include creep relaxation of the stresses which occur when thermal bowing is restrained and asymmetric axial clad creep. The clad temperature changes which accompany such bowing are also investigated and the theoretical results briefly compared with the empirical behaviour. (author)

  17. Suspension scheme for fuel pin

    Butts, C.E.; Gray, H.C.

    1975-01-01

    A description is presented of a nuclear fuel pin suspension arrangement comprising, in combination, a rod; a first beam member connected to said rod at one end; a plurality of parallel-spaced slidable fuel support plates attached to said first beam member, the longitudinal axis of first beam member being perpendicular to the longitudinal axis of each of said fuel support plates, a first coupling means disposed along the length of the first beam member for permitting slidable fuel support plates parallel movement with respect to the longitudinal axis of said first beam member, a second coupling means located at one end of each of slidable fuel plates for slidably engaging first coupling means of first beam member, a second beam member connected to the other end of each of parallel-spaced slidable fuel support plates and providing an extension, second beam member being provided with a third coupling means disposed along the length of second beam member at one end thereof; and a plurality of fuel pins provided with a fourth coupling means located at one end of each fuel pin for slidably engaging third coupling means of second beam member to permit each fuel pin parallel movement with respect to the longitudinal axis of second beam member. (U.S.)

  18. Prototype for the measurement of parameters in the Mammography Unity using photodiodes

    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)

  19. Measurement of environmental radioactivity with photo-diode and Imaging Plate

    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)

  20. Visible light photodiodes and photovoltages from detonation nanodiamonds

    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

  1. Optical fibers and avalanche photodiodes for scintillator counters

    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

  2. Fabrication of detectors and transistors on high-resistivity silicon

    Holland, S.

    1988-06-01

    A new process for the fabrication of silicon p-i-n diode radiation detectors is described. The utilization of backside gettering in the fabrication process results in the actual physical removal of detrimental impurities from critical device regions. This reduces the sensitivity of detector properties to processing variables while yielding low diode reverse-leakage currents. In addition, gettering permits the use of processing temperatures compatible with integrated-circuit fabrication. P-channel MOSFETs and silicon p-i-n diodes have been fabricated simultaneously on 10 kΩ/centerreverse arrowdot/cm silicon using conventional integrated-circuit processing techniques. 25 refs., 5 figs

  3. Silicone metalization

    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.

  4. Large volume cryogenic silicon detectors

    Braggio, C.; Boscardin, M.; Bressi, G.; Carugno, G.; Corti, D.; Galeazzi, G.; Zorzi, N.

    2009-01-01

    We present preliminary measurements for the development of a large volume silicon detector to detect low energy and low rate energy depositions. The tested detector is a one cm-thick silicon PIN diode with an active volume of 31 cm 3 , cooled to the liquid helium temperature to obtain depletion from thermally-generated free carriers. A thorough study has been done to show that effects of charge trapping during drift disappears at a bias field value of the order of 100V/cm.

  5. Large volume cryogenic silicon detectors

    Braggio, C. [Dipartimento di Fisica, Universita di Padova, via Marzolo 8, 35131 Padova (Italy); Boscardin, M. [Fondazione Bruno Kessler (FBK), via Sommarive 18, I-38100 Povo (Italy); Bressi, G. [INFN sez. di Pavia, via Bassi 6, 27100 Pavia (Italy); Carugno, G.; Corti, D. [INFN sez. di Padova, via Marzolo 8, 35131 Padova (Italy); Galeazzi, G. [INFN lab. naz. Legnaro, viale dell' Universita 2, 35020 Legnaro (Italy); Zorzi, N. [Fondazione Bruno Kessler (FBK), via Sommarive 18, I-38100 Povo (Italy)

    2009-12-15

    We present preliminary measurements for the development of a large volume silicon detector to detect low energy and low rate energy depositions. The tested detector is a one cm-thick silicon PIN diode with an active volume of 31 cm{sup 3}, cooled to the liquid helium temperature to obtain depletion from thermally-generated free carriers. A thorough study has been done to show that effects of charge trapping during drift disappears at a bias field value of the order of 100V/cm.

  6. Pinning synchronization of a mobile agent network

    Wang, Lei; Sun, You-xian

    2009-01-01

    We investigate the problem of controlling a group of mobile agents in a plane in order to move them towards a desired orbit via pinning control, in which each agent is associated with a chaotic oscillator coupled with those of neighboring agents, and the pinning strategy is to have the common linear feedback acting on a small fraction of agents by random selection. We explore the effects of the pinning probability, feedback gains and agent density in the pinning synchronization of a mobile agent network under a fast-switching constraint, and perform numerical simulations for validation. In particular, we show that there exists a critical pinning density for network synchronization with an unbounded region: above the threshold, the dynamical network can be controlled by pinning; below it, anarchy prevails. And for the network with a single bounded synchronization region, pinning control has little effect as regards enhancing network synchronizability

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

    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.

  8. Radiated power measurement with AXUV photodiodes in EAST tokamak

    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)

  9. Unicortical self-drilling external fixator pins reduce thermal effects during pin insertion.

    Greinwald, Markus; Varady, Patrick A; Augat, Peter

    2017-12-14

    External fixation is associated with the risk of pin loosening and pin infection potentially associated to thermal bone necrosis during pin insertion. This study aims to investigate if the use of external fixator systems with unicortical pins reduces the heat production during pin insertion compared to fixators with bicortical pins. Porcine bone specimens were employed to determine bone temperatures during insertion of fixator pins. Two thermographic cameras were used for a simultaneous temperature measurement on the bone surface (top view) and a bone cross-section (front view). Self-drilling unicortical and bicortical pins were inserted at different rotational speeds: (30-600) rpm. Maximum and mean temperatures of the emerging bone debris, bone surface and bone cross-section were analyzed. Maximum temperatures of up to 77 ± 26 °C were measured during pin insertion in the emerging debris and up to 42 ± 2 °C on the bone surface. Temperatures of the emerging debris increased with increasing rotational speeds. Bicortical pin insertion generated significantly higher temperatures at low insertion speed (30 rpm) CONCLUSION: The insertion of external fixator pins can generate a considerable amount of heat around the pins, primarily emerging from bone debris and at higher insertion speeds. Our findings suggest that unicortical, self-drilling fixator pins have a decreased risk for thermal damage, both to the surrounding tissue and to the bone itself.

  10. Pin Wire Coating Trip Report

    Spellman, G P

    2004-01-01

    A meeting to discuss the current pin wire coating problems was held at the Reynolds plant in Los Angeles on 2MAR04. The attendance list for Reynolds personnel is attached. there was an initial presentation which gave a brief history and the current status of pin wire coating at Reynolds. There was a presentation by Lori Primus on the requirements and issues for the coating. There was a presentation by Jim Smith of LANL on the chemistry and to some extent process development done to date. There was a long session covering what steps should be taken in the short term and, to a lesser extent, the long term. The coating currently being used is a blend of two polymers, polyethersulfone and polyparabanic acid (PPA) and some TiO2 filler. This system was accepted and put into production when the pin wire coating was outsourced to another company in 1974. When that company no longer was interested, the wire coating was brought in-house to Reynolds. At that time polyparabanic acid was actually a commercial product available from Exxon under the trade name Tradlon. However, it appears that the material used at Reynolds was synthesized locally. Also, it appears that a single large batch was synthesized in that time period and used up to 1997 when the supply ran out. The reason for the inclusion of TiO2 is not known although it does act as a rheological thickener. However, a more controlled thickening can be obtained with materials such as fumed silica. This material would have less likelihood of causing point imperfections in the coatings. Also, the mixing technique being used for all stages of the process is a relatively low shear ball mill process and the author recommends a high shear process such as a three roll paint mill, at least for the final mixing. Since solvent is added to the powder at Reynolds, it may be that they need to have the paint mill there

  11. Transient survivability of LMR oxide fuel pins

    Weber, E.T.; Pitner, A.L.; Bard, F.E.; Culley, G.E.; Hunter, C.W.

    1986-01-01

    Fuel pin integrity during transient events must be assessed for both the core design and safety analysis phases of a reactor project. A significant increase in the experience related to limits of integrity for oxide fuel pins in transient overpower events has been realized from testing of fuel pins irradiated in FFTF and PFR. Fourteen FFTF irradiated fuel pins were tested in TREAT, representing a range of burnups, overpower ramp rates and maximum overpower conditions. Results of these tests along with similar testing in the PFR/TREAT program, provide a demonstration of significant safety margins for oxide fuel pins. Useful information applied in analytical extrapolation of fuel pin test data have been developed from laboratory transient tests on irradiated fuel cladding (FCTT) and on unirradiated fuel pellet deformation. These refinements in oxide fuel transient performance are being applied in assessment of transient capabilities of long lifetime fuel designs using ferritic cladding

  12. Cesium migration in LMFBR fuel pins

    Karnesky, R.A.; Jost, J.W.; Stone, I.Z.

    1978-10-01

    The factors affecting the axial migration of cesium in mixed oxide fuel pins and the effects of cesium migration on fuel pin performance are examined. The development and application of a correlated model which will predict the occurrence of cesium migration in a mixed oxide (75 w/o UO 2 + 25 w/o PuO 2 ) fuel pins over a wide range of fabrication and irradiation conditions are described

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

    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.

  14. Amplifiers dedicated for large area SiC photodiodes

    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.

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

    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

  16. FFTF fuel pin design bases and performance

    Cox, C.M.; Hanson, J.E.; Roake, W.E.; Slember, R.J.; Weber, C.E.; Millunzi, A.C.

    1975-04-01

    The FFTF fuel pin was conservatively designed to meet thermal and structural performance requirements in the categories normal operation, upset events, emergency events, and hypothetical, faulted events. The fuel pin operating limits consistent with these requirements were developed from a strong fuel pin irradiation testing program scoped to define the performance capability under relevant steady state and transient conditions. Comparison of the results of the irradiation testing program with design requirements indicates that the FFTF fuel pin can exceed its goal burnup of 80,000 MWd/MTM. (U.S.)

  17. Integral Fast Reactor fuel pin processor

    Levinskas, D.

    1993-01-01

    This report discusses the pin processor which receives metal alloy pins cast from recycled Integral Fast Reactor (IFR) fuel and prepares them for assembly into new IFR fuel elements. Either full length as-cast or precut pins are fed to the machine from a magazine, cut if necessary, and measured for length, weight, diameter and deviation from straightness. Accepted pins are loaded into cladding jackets located in a magazine, while rejects and cutting scraps are separated into trays. The magazines, trays, and the individual modules that perform the different machine functions are assembled and removed using remote manipulators and master-slaves

  18. Magnetic pinning in superconductor-ferromagnet multilayers

    Bulaevskii, L. N.; Chudnovsky, E. M.; Maley, M. P.

    2000-01-01

    We argue that superconductor/ferromagnet multilayers of nanoscale period should exhibit strong pinning of vortices by the magnetic domain structure in magnetic fields below the coercive field when ferromagnetic layers exhibit strong perpendicular magnetic anisotropy. The estimated maximum magnetic pinning energy for single vortex in such a system is about 100 times larger than the pinning energy by columnar defects. This pinning energy may provide critical currents as high as 10 6 -10 7 A/cm 2 at high temperatures (but not very close to T c ) at least in magnetic fields below 0.1 T. (c) 2000 American Institute of Physics

  19. Magnetic pinning in superconductor-ferromagnet multilayers

    Bulaevskii, L. N. [Department of Physics and Astronomy, CUNY Lehman College 250 Bedford Park Boulevard West, Bronx, New York 10468-1589 (United States); Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Chudnovsky, E. M. [Department of Physics and Astronomy, CUNY Lehman College, 250 Bedford Park Boulevard West, Bronx, New York 10468-1589 (United States); Maley, M. P. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2000-05-01

    We argue that superconductor/ferromagnet multilayers of nanoscale period should exhibit strong pinning of vortices by the magnetic domain structure in magnetic fields below the coercive field when ferromagnetic layers exhibit strong perpendicular magnetic anisotropy. The estimated maximum magnetic pinning energy for single vortex in such a system is about 100 times larger than the pinning energy by columnar defects. This pinning energy may provide critical currents as high as 10{sup 6}-10{sup 7} A/cm{sup 2} at high temperatures (but not very close to T{sub c}) at least in magnetic fields below 0.1 T. (c) 2000 American Institute of Physics.

  20. Fabrication of FFTF fuel pin wire wrap

    Epperson, E.M.

    1980-06-01

    Lateral spacing between FFTF fuel pins is required to provide a passageway for the sodium coolant to flow over each pin to remove heat generated by the fission process. This spacing is provided by wrapping each fuel pin with type 316 stainless steel wire. This wire has a 1.435mm (0.0565 in.) to 1.448mm (0.0570 in.) diameter, contains 17 +- 2% cold work and was fabricated and tested to exacting RDT Standards. About 500 kg (1100 lbs) or 39 Km (24 miles) of fuel pin wrap wire is used in each core loading. Fabrication procedures and quality assurance tests are described

  1. Analysis of IV characteristics of solar cells made of hydrogenated amorphous, polymorphous and microcrystalline silicon

    Hamadeh, H.

    2009-03-01

    The IV characteristics of pin solar cells made of amorphous, polymorphous and microcrystalline silicon were investigated. The temperature dependence was measured in the temperature range between 150 K and 395 K. This range covers the most terrestrial applications condition. Using simplex procedure, the IV parameter of the cells were deduce using line fitting. It has been shown that polymorphous silicon shows electrical properties that are close to properties of microcrystalline silicon but as it is well known, polymorphous silicon shows higher absorption similar to amorphous silicon. The polymorphous silicon solar cells showed higher efficiencies, lower shunting and higher filling factors. In the above mentioned temperature range, polymorphous silicon is the better material for the manufacturing of thin film hydrogenated silicon pin solar cells. More investigations concerning the structural properties are necessary to make stronger conclusions in regards to the stability of the material, what we hope to do in the future. (author)

  2. Reduction of halo pin site morbidity with a new pin care regimen.

    Kazi, Hussain Anthony; de Matas, Marcus; Pillay, Robin

    2013-06-01

    A retrospective analysis of halo device associated morbidity over a 4-year period. To assess the impact of a new pin care regimen on halo pin site related morbidity. Halo orthosis treatment still has a role in cervical spine pathology, despite increasing possibilities of open surgical treatment. Published figures for pin site infection range from 12% to 22% with pin loosening from 7% to 50%. We assessed the outcome of a new pin care regimen on morbidity associated with halo spinal orthoses, using a retrospective cohort study from 2001 to 2004. In the last two years, our pin care regimen was changed. This involved pin site care using chlorhexidene & regular torque checking as part of a standard protocol. Previously, povidone iodine was used as skin preparation in theatre, followed by regular sterile saline cleansing when pin sites became encrusted with blood. There were 37 patients in the series, the median age was 49 (range, 22-83) and 20 patients were male. The overall infection rate prior to the new pin care protocol was 30% (n=6) and after the introduction, it dropped to 5.9% (n=1). This difference was statistically significant (p<0.05). Pin loosening occurred in one patient in the group prior to the formal pin care protocol (3%) and none thereafter. Reduced morbidity from halo use can be achieved with a modified pin cleansing and tightening regimen.

  3. Phosphorylation of conserved PIN motifs directs Arabidopsis PIN1 polarity and auxin transport

    Huang, F.; Kemel Zago, M.; Abas, L.; van Marion, A.; Galván-Ampudia, C.S.; Offringa, R.

    2010-01-01

    Polar cell-to-cell transport of auxin by plasma membrane-localized PIN-FORMED (PIN) auxin efflux carriers generates auxin gradients that provide positional information for various plant developmental processes. The apical-basal polar localization of the PIN proteins that determines the direction of

  4. A fiber-optic technique for the measurement of contact angle in a clearance-fit pin-loaded hole

    Prabhakaran, R.; Naik, R. A.

    1987-01-01

    A fiber-optic technique for measuring contact angle during pin loading of a specimen is proposed. The experimental design and procedures for loading a 49.8-mm-diameter instrumented pin into an quasi-isotropic graphite-epoxy specimen are described. The optical fiber was located just above the surface of the pin outer diameter in order to obtain accurate pin-hole contact-angle measurements at increasing load levels. The movement of the optical fiber through the no-contact, contact, and no-contact regions is discussed; the photodiode output decreased monotonically as the fiber moved from the no-contact to the contact region and then decreased monotonically as the fiber moved from the contact region to the no-contact region. Variations in the contact angle measurements are examined as function of applied load level. The measurements are compared to contact angle values obtained using a finite element analysis and an electrical technique; it is determined that the data correlate well.

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

    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,

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

    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.)

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

    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)

  8. Synchronizability on complex networks via pinning control

    Keywords. Complex network; the pinning synchronization; synchronizability. ... The findings reveal the relationship between the decreasing speed of maximum eigenvalue sequence of the principal submatrices for coupling matrix and the synchronizability on complex networks via pinning control. We discuss the ...

  9. Breached-pin testing in the US

    Mahagin, D.E.; Lambert, J.D.B.

    1981-04-01

    Experience gained at EBR-II by the late 1970's from a significant number of failures in experimental fuel-pin irradiations forms the basis of a program directed towards the characterization of breached pins. The questions to be answered and the issues raised by further testing are discussed

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

    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.

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

    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.

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

    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).

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

    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

  14. TACO: fuel pin performance analysis

    Stoudt, R.H.; Buchanan, D.T.; Buescher, B.J.; Losh, L.L.; Wilson, H.W.; Henningson, P.J.

    1977-08-01

    The thermal performance of fuel in an LWR during its operational lifetime must be described for LOCA analysis as well as for other safety analyses. The determination of stored energy in the LOCA analysis, for example, requires a conservative fuel pin thermal performance model that is capable of calculating fuel and cladding behavior, including the gap conductance between the fuel and cladding, as a function of burnup. The determination of parameters that affect the fuel and cladding performance, such as fuel densification, fission gas release, cladding dimensional changes, fuel relocation, and thermal expansion, should be accounted for in the model. Babcock and Wilcox (B and W) has submitted a topical report, BAW-10087P, December 1975, which describes their thermal performance model TACO. A summary of the elements that comprise the TACO model and an evaluation are presented

  15. Incommensurate pinning mechanism in KCP

    Apostol, M.; Baldea, I.

    1984-07-01

    A new pinning mechanism (termed incommensurate) is put forward for K 2 Pt(CN) 4 Brsub(0.3)x3.2H 2 O(KCP) based on the Q-quasi-modulated distribution of the bromine anions (Br-bar) along the chain axis (Q/2 being the Fermi momentum reduced to the first Brillouin zone). The different origins of the direct current (d.c.) thermally-activated gap and optical gap are thereby explained. The spectrum of the collective excitations (amplitudons and phasons) and the dielectric function are calculated for the charge density wave (CDW) state. Fair agreement is obtained with the optical and neutron scattering data. (author)

  16. Pinning impulsive control algorithms for complex network

    Sun, Wen; Lü, Jinhu; Chen, Shihua; Yu, Xinghuo

    2014-01-01

    In this paper, we further investigate the synchronization of complex dynamical network via pinning control in which a selection of nodes are controlled at discrete times. Different from most existing work, the pinning control algorithms utilize only the impulsive signals at discrete time instants, which may greatly improve the communication channel efficiency and reduce control cost. Two classes of algorithms are designed, one for strongly connected complex network and another for non-strongly connected complex network. It is suggested that in the strongly connected network with suitable coupling strength, a single controller at any one of the network's nodes can always pin the network to its homogeneous solution. In the non-strongly connected case, the location and minimum number of nodes needed to pin the network are determined by the Frobenius normal form of the coupling matrix. In addition, the coupling matrix is not necessarily symmetric or irreducible. Illustrative examples are then given to validate the proposed pinning impulsive control algorithms

  17. Resistance projection welding small pins in vacuum tube feedthrough assembly

    Kuncz, F. Jr.

    1980-01-01

    Resistance projection welding of two stainless steel pins to a cup is successfully accomplished by specially designed electrodes and by forming domes on the pin ends. Details of electrode and pin construction are given, as well as welding parameters

  18. High energy x-ray radiography and computed tomography of bridge pins

    Green, R E; Logan, C M; Martz, H E; Updike, E; Waters, A M

    1999-01-01

    Bridge pins were used in the hanger assemblies for some multi-span steel bridges built prior to the 1980's, and are sometimes considered fracture critical elements of a bridge. During a test on a bridge conducted by the Federal Highway Administration (FHWA), ultrasonic field inspection results indicated that at least two pins contained cracks. Several pins were removed and selected for further examination. This provided an excellent opportunity to learn more about these pins and the application of x-ray systems at Lawrence Livermore National Laboratory (LLNL), as well as to learn more about the application of different detectors recently obtained by LLNL. Digital radiographs and computed tomography (CT) were used to characterize the bridge pins, using a LINAC x-ray source with a 9-MV bremsstrahlung spectrum. We will describe the performance of two different digital radiographic detectors. One is a detector system frequently used at LLNL consisting of a scintillator glass optically coupled to a CCD camera. The other detector is a new amorphous silicon detector recently acquired by LLNL

  19. Pin fin compliant heat sink with enhanced flexibility

    Schultz, Mark D.

    2018-04-10

    Heat sinks and methods of using the same include a top and bottom plate, at least one of which has a plurality of pin contacts flexibly connected to one another, where the plurality of pin contacts have vertical and lateral flexibility with respect to one another; and pin slice layers, each having multiple pin slices, arranged vertically between the top and bottom plates such that the plurality of pin slices form substantially vertical pins connecting the top and bottom plates.

  20. Sheet resistance effects in mercury cadmium telluride implanted photodiodes

    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)

  1. Silicon detectors

    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.)

  2. Cesium chemistry in GCFR fuel pins

    Fee, D.C.; Johnson, C.E.

    1979-01-01

    The fuel rod design for the Gas Cooled Fast-Breeder Reactor (GCFR) is similar to that employed for the Liquid Metal Fast Breeder Reactor (LMFBR) with the exception of the unique features inherent to the use of helium as the coolant. These unique design features include the use of (1) vented and pressure-equalized fuel rods, and (2) ribbed cladding along 75% of the fuel section. The former design feature enables reduction in cladding thickness and prevention of possible creep collapse of the cladding due to the high coolant pressure (8.5 MPa). The latter design feature brings about improved heat transfer characteristics. Each GCFR fuel rod is vented to a manifold whereby gaseous fission products diffusing out of the fuel pin are retained on charcoal traps. As a result, the internal pressure of a GCFR fuel pin does not increase during irradiation. In addition, the venting system also maintains the pressure within the fuel pin slightly below (0.3 to 0.5 MPa) the coolant pressure outside the fuel pin. Consequently, should a breach occur in the cladding, helium flows into the breached fuel pin thereby minimizing fission product contamination of the coolant. These desirable aspects of a GCFR fuel pin can be maintained only as long as axial gas transport paths are available and operating within the fuel pin

  3. Vortex lattice melting, pinning and kinetics

    Doniach, S.; Ryu, S.; Kapitulnik, A.

    1994-01-01

    The phenomenology of the high T c superconductors is discussed both at the level of the thermodynamics of melting of the Abrikosov flux lattice and in terms of the melting and kinetics of the flux lattice for a pinned system. The authors review results on 3D melting obtained by a Monte Carlo simulation approach in which the 2D open-quotes pancakeclose quotes vortices are treated as statistical variables. The authors discuss pinning in the context of the strong pinning regime in which the vortex density given in terms of the applied field B is small compared to that represented by an effective field B pin measuring the pinning center density. The authors introduce a new criterion for the unfreezing of a vortex glass on increase of magnetic field or temperature, in the strong pinning, small field unit. The authors model this limit in terms of a single flux line interacting with a columnar pin. This model is studied both analytically and by computer simulation. By applying a tilt potential, the authors study the kinetics of the vortex motion in an external current and show that the resulting current-voltage characteristic follows a basic vortex glass-like scaling relation in the vicinity of the depinning transition

  4. Computer simulation of vortex pinning in type II superconductors. II. Random point pins

    Brandt, E.H.

    1983-01-01

    Pinning of vortices in a type II superconductor by randomly positioned identical point pins is simulated using the two-dimensional method described in a previous paper (Part I). The system is characterized by the vortex and pin numbers (N/sub v/, N/sub p/), the vortex and pin interaction ranges (R/sub v/, R/sub p/), and the amplitude of the pin potential A/sub p/. The computation is performed for many cases: dilute or dense, sharp or soft, attractive or repulsive, weak or strong pins, and ideal or amorphous vortex lattice. The total pinning force F as a function of the mean vortex displacment X increases first linearly (over a distance usually much smaller than the vortex spacing and than R/sub p/) and then saturates, fluctuating about its averaging F-bar. We interpret F-bar as the maximum pinning force j/sub c/B of a large specimen. For weak pins the prediction of Larkin and Ovchinnikov for two-dimensional collective pinning is confirmed: F-bar = const. iW/R/sub p/c 66 , where W-bar is the mean square pinning force and c 66 is the shear modulus of the vortex lattice. If the initial vortex lattice is chosen highly defective (''amorphous'') the constant is 1.3--3 times larger than for the ideal triangular lattice. This finding may explain the often observed ''history effect.'' The function F-bar(A/sub p/) exhibits a jump, which for dilute, sharp, attractive pins occurs close to the ''threshold value'' predicted for isolated pins by Labusch. This jump reflects the onset of plastic deformation of the vortex lattice, and in some cases of vortex trapping, but is not a genuine threshold

  5. A new CMOS SiGeC avalanche photo-diode pixel for IR sensing

    Augusto, Carlos; Forester, Lynn; Diniz, Pedro C.

    2009-05-01

    Near-infra-red sensing with silicon is limited by the bandgap of silicon, corresponding to a maximum wavelength of absorption of 1.1 μm. A new type of CMOS sensor is presented, which uses a SiGeC epitaxial film in conjunction with novel device architecture to extend absorption into the infra-red. The SiGeC film composition and thickness determine the spectrum of absorption; in particular for SiGeC superlattices, the layer ordering to create pseudo direct bandgaps is the critical parameter. In this new device architecture, the p-type SiGeC film is grown on an active region surrounded by STI, linked to the S/D region of an adjacent NMOS, under the STI by a floating N-Well. On a n-type active, a P-I-N device is formed, and on a p-type active, a P-I-P device is formed, each sensing different regions of the spectrum. The SiGeC films can be biased for avalanche operation, as the required vertical electric field is confined to the region near the heterojunction interface, thereby not affecting the gate oxide of the adjacent NMOS. With suitable heterojunction and doping profiles, the avalanche region can also be bandgap engineered, allowing for avalanche breakdown voltages that are compatible with CMOS devices.

  6. Electro-optical fuel pin identification system

    Kirchner, T.L.

    1978-09-01

    A prototype Electro-Optical Fuel Pin Identification System referred to as the Fuel Pin Identification System (FPIS) has been developed by the Hanford Engineering Development Laboratory (HEDL) in support of the Fast Flux Test Facility (FFTF) presently under construction at HEDL. The system is designed to remotely read an alpha-numeric identification number that is roll stamped on the top of the fuel pin end cap. The prototype FPIS consists of four major subassemblies: optical read head, digital compression electronics, video display, and line printer

  7. Flux pinning characteristics of YBCO coated conductor

    Matsushita, T.; Watanabe, T.; Fukumoto, Y.; Yamauchi, K.; Kiuchi, M.; Otabe, E.S.; Kiss, T.; Watanabe, T.; Miyata, S.; Ibi, A.; Muroga, T.; Yamada, Y.; Shiohara, Y.

    2005-01-01

    Flux pinning properties of PLD-processed YBCO coated conductors deposited on IBAD substrate are investigated. The thickness of YBCO layer is changed in the range of 0.27-1.0 μm. The thickness dependence of critical current density, n-value and irreversibility field are measured in a wide range of magnetic field. The results are compared with the theoretical flux creep-flow model. It is found that these pinning properties are strongly influenced by the thickness as well as the pinning strength. Optimum condition for high field application of this superconductor is discussed

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

    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

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

    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

  10. Pinning and creep in superconductors

    Ovchinnikov, Yu.N.

    1994-01-01

    All superconductors can be separated into two large groups: type I and type II. The behaviour of these two groups in a magnetic field is quite different. The superconductors of type I, in a strong magnetic field, enter the intermediate state. Phenomenological picture of this state was given by Landau. The type II superconductors, in strong magnetic fields, form the mixed state (or Shubnikov phase). The microscopic picture of the mixed state was given by Abrikosov on the basis of Ginzburg-Landau equations. In ideal homogeneous superconductors the free energy is not changed if all the vortex structure is shifted on some distance u. The transport current will be proportional, therefore, to the electric field E. All the real superconductors, however, are inhomogeneous. Inhomogeneities interact with vortex lattice and pin it. In this new state the transport current below some critical value does not lead to the motion of the flux lattice and to the energy dissipation. The value of critical current strongly depends on the type of inhomogeneities, on the value of magnetic field and on temperature. In new layered superconductors, the critical current depends also on the orientation of the magnetic field B with respect to the layer planes. Temperature and quantum fluctuations lead to the transition between different metastable states in superconductors with current. As a result, the vortex lattice slowly moves (creep phenomenon). Below we will briefly discuss all these phenomena. (orig.)

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

    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.

  12. Vortex pinning by point defect in superconductors

    Liao Hongyin; Zhou Shiping; Du Haochen

    2003-01-01

    We apply the periodic time-dependent Ginzburg-Landau model to study vortex distribution in type-II superconductors with a point-like defect and square pinning array. A defect site will pin vortices, and a periodic pinning array with right geometric parameters, which can be any form designed in advance, shapes the vortex pattern as external magnetic field varies. The maximum length over which an attractive interaction between a pinning centre and a vortex extends is estimated to be about 6.0ξ. We also derive spatial distribution expressions for the order parameter, vector potential, magnetic field and supercurrent induced by a point defect. Theoretical results and numerical simulations are compared with each other and they are consistent

  13. Pinning Synchronization of Switched Complex Dynamical Networks

    Liming Du

    2015-01-01

    Full Text Available Network topology and node dynamics play a key role in forming synchronization of complex networks. Unfortunately there is no effective synchronization criterion for pinning synchronization of complex dynamical networks with switching topology. In this paper, pinning synchronization of complex dynamical networks with switching topology is studied. Two basic problems are considered: one is pinning synchronization of switched complex networks under arbitrary switching; the other is pinning synchronization of switched complex networks by design of switching when synchronization cannot achieved by using any individual connection topology alone. For the two problems, common Lyapunov function method and single Lyapunov function method are used respectively, some global synchronization criteria are proposed and the designed switching law is given. Finally, simulation results verify the validity of the results.

  14. Nuclear fuel pin controlled failure device

    Schlenker, L.D.

    1975-01-01

    Each fuel pin of a fuel assembly for a water-cooled nuclear reactor is provided with means for rupturing the cladding tube at a predetermined location if an abnormal increase in pressure of the gases present occurs due to a loss-of-coolant accident. Preferably all such rupture means are oriented to minimize the hydraulic resistance to the flow of emergency core coolant such as all rupture means pointing in the same direction. Rupture means may be disposed at different elevations in adjacent fuel pins and, further, fuel pins may be provided with two or more rupture means, one of which is in the upper portion of the fuel pin. Rupture means are mechanical as by providing a locally weakened condition of a controlled nature in the cladding. (U.S.)

  15. Ultrasonic inspections of fuel alignment pins

    Rathgeb, W.; Schmid, R.

    1994-01-01

    As a remedy to the practical problem of defects in fuel alignment pins made of Inconel X750, an inspection technique has been developed which fully meets the requirements of detecting defects. The newly used fuel alignment pins made of austenite are easy to test and therefore satisfy the necessity of further inspections.For the fuel alignment pins of the upper core structure a safe and fast inspection technique was made available. The inspection sensitivity is high and it is possible to give quantitative directions concerning defect orientation and depth. After the required inspections had been concluded in 1989, a total of 18 inspections were carried out in various national and international nuclear power plants in the following years. During this time more than 6000 fuel alignment pines were examined.For the fuel alignment pins the inspection technique provided could increase the understanding of the defect process. This technique contributed to the development of an adaptive and economical repair strategy. ((orig.))

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

    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. Application of PIN diodes in Physics Research

    Ramirez-Jimenez, F. J.; Mondragon-Contreras, L.; Cruz-Estrada, P.

    2006-01-01

    A review of the application of PIN diodes as radiation detectors in different fields of Physics research is presented. The development and research in semiconductor technology, the use of PIN diodes in particle counting, X-and γ-ray spectroscopy, medical applications and charged particle spectroscopy are considered. Emphasis is made in the activities realized in the different research and development Mexican institutions dealing with this kind of radiation detectors

  18. IMp: The customizable LEGO® Pinned Insect Manipulator

    Steen Dupont

    2015-02-01

    Full Text Available We present a pinned insect manipulator (IMp constructed of LEGO® building bricks with two axes of movement and two axes of rotation. In addition we present three variants of the IMp to emphasise the modular design, which facilitates resizing to meet the full range of pinned insect specimens, is fully customizable, collapsible, affordable and does not require specialist tools or knowledge to assemble.

  19. IMp: The customizable LEGO® Pinned Insect Manipulator

    Dupont, Steen; Price, Benjamin; Blagoderov, Vladimir

    2015-01-01

    Abstract We present a pinned insect manipulator (IMp) constructed of LEGO® building bricks with two axes of movement and two axes of rotation. In addition we present three variants of the IMp to emphasise the modular design, which facilitates resizing to meet the full range of pinned insect specimens, is fully customizable, collapsible, affordable and does not require specialist tools or knowledge to assemble. PMID:25685035

  20. Anisotropic flux pinning in high Tc superconductors

    Kolesnik, S.; Igalson, J.; Skoskiewicz, T.; Szymczak, R.; Baran, M.; Pytel, K.; Pytel, B.

    1995-01-01

    In this paper we present a comparison of the results of FC magnetization measurements on several Pb-Sr-(Y,Ca)-Cu-O crystals representing various levels of flux pinning. The pinning centers in our crystals have been set up during the crystal growth process or introduced by neutron irradiation. Some possible explanations of the observed effects, including surface barrier, flux-center distribution and sample-shape effects, are discussed. ((orig.))

  1. Investigation on macroscopic cross section model for BWR pin-by-pin core analysis - 118

    Fujita, T.; Tada, K.; Yamamoto, A.; Yamane, Y.; Kosaka, S.; Hirano, G.

    2010-01-01

    A cross section model used in the pin-by-pin core analysis for BWR is investigated. In the pin-by-pin core calculation method, pin-cell averaged cross sections are calculated for many combinations of state and history variables that have influences on the cross section and are tabulated prior to the core calculations. Variation of a cross section in a core simulator is classified into two different types, i.e., the instantaneous effect and the history effect. The instantaneous effect is incorporated by the variation of cross section which is caused by the instantaneous change of state variables. For this effect, the exposure, the void fraction, the fuel temperature, the moderator temperature and the control rod are used as indexes. The history effect is the cumulative effect of state variables. We treat this effect with a unified approach using the spectral history. To confirm accuracy of the cross section model, the pin-by-pin fission rate distribution and the k-infinity of fuel assembly which are obtained with the tabulated and the reference cross sections are compared. For the instantaneous effect, the present cross section model well reproduces the reference results for all off-nominal conditions. For the history effect, however, considerable differences both on the pin-by-pin fission rate distribution and the k-infinity are observed at high exposure points. (authors)

  2. A macroscopic cross-section model for BWR pin-by-pin core analysis

    Fujita, Tatsuya; Endo, Tomohiro; Yamamoto, Akio

    2014-01-01

    A macroscopic cross-section model used in boiling water reactor (BWR) pin-by-pin core analysis is studied. In the pin-by-pin core calculation method, pin-cell averaged cross sections are calculated for many combinations of core state and depletion history variables and are tabulated prior to core calculations. Variations of cross sections in a core simulator are caused by two different phenomena (i.e. instantaneous and history effects). We treat them through the core state variables and the exposure-averaged core state variables, respectively. Furthermore, the cross-term effect among the core state and the depletion history variables is considered. In order to confirm the calculation accuracy and discuss the treatment of the cross-term effect, the k-infinity and the pin-by-pin fission rate distributions in a single fuel assembly geometry are compared. Some cross-term effects could be negligible since the impacts of them are sufficiently small. However, the cross-term effects among the control rod history (or the void history) and other variables have large impacts; thus, the consideration of them is crucial. The present macroscopic cross-section model, which considers such dominant cross-term effects, well reproduces the reference results and can be a candidate in practical applications for BWR pin-by-pin core analysis on the normal operations. (author)

  3. Thermo-Optic Characterization of Silicon Nitride Resonators for Cryogenic Photonic Circuits

    Elshaari, A.W.A.; Esmaeil Zadeh, I.; Jöns, K.D.; Zwiller, Val

    2016-01-01

    <p>In this paper, we characterize the Thermo-optic properties of silicon nitride ring resonators between 18 and 300 K. The Thermo-optic coefficients of the silicon nitride core and the oxide cladding are measured by studying the temperature dependence of the resonance wavelengths. The resonant modes

  4. Improved pinning by multiple in-line damage

    Weinstein, Roy [Beam Particle Dynamics Laboratories, University of Houston, Houston, TX 77204-5005 (United States); Sawh, Ravi-Persad [Beam Particle Dynamics Laboratories, University of Houston, Houston, TX 77204-5005 (United States); Gandini, Alberto [Beam Particle Dynamics Laboratories, University of Houston, Houston, TX 77204-5005 (United States); Parks, Drew [Beam Particle Dynamics Laboratories, University of Houston, Houston, TX 77204-5005 (United States)

    2005-02-01

    Columnar pinning centres provide the largest pinning potential, U{sub pin}, but not the greatest J{sub c} or pinnable field, B{sub pin}. Characteristics of ion-generated columnar defects which limit J{sub c} and B{sub pin} are discussed, including reduction of the percolation path, and the need for a larger number of columns of damage, for pinning, than are usually estimated. It is concluded that columnar pinning centres limit B{sub pin} to less than 4 T, and also severely reduce J{sub c}. The goal of maximizing U{sub pin}, via columnar centres, appears to have obscured a more rewarding approach and resulted in neglect of a large regime of ion interactions. Evidence is reviewed that multiple in-line damage (MILD), described herein, can provide orders of magnitude higher J{sub c} and B{sub pin}, despite providing lower U{sub pin}. The MILD pinning centre morphology is discussed, and it is estimated that for present-day large grain high T{sub c} superconductors, a J{sub c} value of {approx}10{sup 6}Acm{sup -2} is obtainable at 77 K, even when crystal plane alignment and weak links are not improved. In addition, the pinned field is increased by over an order of magnitude. An experiment is proposed to confirm these calculations, directly compare MILD pinning to continuous columnar pinning, and determine the optimum MILD structure. Applications of MILD pinning are discussed.

  5. InGaAs/GaAsSb Type-II superlattice based photodiodes for short wave infrared detection

    Uliel, Y.; Cohen-Elias, D.; Sicron, N.; Grimberg, I.; Snapi, N.; Paltiel, Y.; Katz, M.

    2017-08-01

    Short Wave Infra-Red (SWIR) photodetectors operating above the response cutoff of InGaAs- based detectors (1.7-2.5 μm) are required for both defense and civil applications. Type II Super-Lattices (T2SL) were recently proposed For near- room temperature SWIR detection as a possible system enabling bandgap adjustment in the required range. The work presented here focuses on a T2SL with alternating nano-layers of InGaAs and GaAsSb lattice-matched to an InP substrate. A near room temperature SWIR cutoff of 2.4 μm was measured. Electrical junctions were realized using Zn diffusion p-doping process. We realized and studied both mesa- and selective diffusion- based p-i-n photodiodes. Dark currents of mesa-based devices were 1.5 mA/cm2 and 32 μA/cm2 at 300 and 230 K respectively. Dark currents were reduced to 1.2 mA/cm2 and 12 μA/cm2 respectively by utilizing the selective diffusion process. The effect of operating voltage is discussed. At 300 K the quantum efficiency was up to 40% at 2.18 μm in mesa devices. D∗ was 1.7 ×1010cm ·√{Hz } /W at 2 μm.

  6. Ge/graded-SiGe multiplication layers for low-voltage and low-noise Ge avalanche photodiodes on Si

    Miyasaka, Yuji; Hiraki, Tatsurou; Okazaki, Kota; Takeda, Kotaro; Tsuchizawa, Tai; Yamada, Koji; Wada, Kazumi; Ishikawa, Yasuhiko

    2016-04-01

    A new structure is examined for low-voltage and low-noise Ge-based avalanche photodiodes (APDs) on Si, where a Ge/graded-SiGe heterostructure is used as the multiplication layer of a separate-absorption-carrier-multiplication structure. The Ge/SiGe heterojunction multiplication layer is theoretically shown to be useful for preferentially enhancing impact ionization for photogenerated holes injected from the Ge optical-absorption layer via the graded SiGe, reflecting the valence band discontinuity at the Ge/SiGe interface. This property is effective not only for the reduction of operation voltage/electric field strength in Ge-based APDs but also for the reduction of excess noise resulting from the ratio of the ionization coefficients between electrons and holes being far from unity. Such Ge/graded-SiGe heterostructures are successfully fabricated by ultrahigh-vacuum chemical vapor deposition. Preliminary pin diodes having a Ge/graded-SiGe multiplication layer act reasonably as photodetectors, showing a multiplication gain larger than those for diodes without the Ge/SiGe heterojunction.

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

    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)

  8. Heterogeneous neutron-leakage model for PWR pin-by-pin calculation

    Li, Yunzhao; Zhang, Bin; Wu, Hongchun; Shen, Wei

    2017-01-01

    Highlights: •The derivation of the formula of the leakage model is introduced. This paper evaluates homogeneous and heterogeneous leakage models used in PWR pin-by-pin calculation. •The implements of homogeneous and heterogeneous leakage models used in pin-cell homogenization of the lattice calculation are studied. A consistent method of cooperation between the heterogeneous leakage model and the pin-cell homogenization theory is proposed. •Considering the computational cost, a new buckling search scheme is proposed to reach the convergence faster. The computational cost of the newly proposed neutron balance scheme is much less than the power-method scheme and the linear-interpolation scheme. -- Abstract: When assembly calculation is performed with the reflective boundary condition, a leakage model is usually required in the lattice code. The previous studies show that the homogeneous leakage model works effectively for the assembly homogenization. However, it becomes different and unsettled for the pin-cell homogenization. Thus, this paper evaluates homogeneous and heterogeneous leakage models used in pin-by-pin calculation. The implements of homogeneous and heterogeneous leakage models used in pin-cell homogenization of the lattice calculation are studied. A consistent method of cooperation between the heterogeneous leakage model and the pin-cell homogenization theory is proposed. Considering the computational cost, a new buckling search scheme is proposed to reach the convergence faster. For practical reactor-core applications, the diffusion coefficients determined by the transport cross-section or by the leakage model are compared with each other to determine which one is more accurate for the Pressurized Water Reactor pin-by-pin calculation. Numerical results have demonstrated that the heterogeneous leakage model together with the diffusion coefficient determined by the heterogeneous leakage model would have the higher accuracy. The new buckling search

  9. Studies of avalanche photodiodes for scintillating fibre tracking readout

    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

    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

    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

    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. Development of an X-ray detector using photodiodes

    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)

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

    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.

  15. Pinning of fullerene lowest unoccupied molecular orbital edge at the interface with standing up copper phthalocyanine

    Wang, Chenggong; Irfan, Irfan; Turinske, Alexander J.; Gao, Yongli

    2012-01-01

    The electronic structure evolution of interfaces of fullerene (C 60 ) with copper phthalocyanine (CuPc) on highly oriented pyrolitic graphite (HOPG) and on native silicon oxide has been investigated with ultra-violet photoemission spectroscopy and inverse photoemission spectroscopy. The lowest unoccupied molecular orbital edge of C 60 was found to be pinned at the interface with CuPc on SiO 2 . A substantial difference in the electron affinity of CuPc on the two substrates was observed as the orientation of CuPc is lying flat on HOPG and standing up on SiO 2 . The ionization potential and electron affinity of C 60 were not affected by the orientation of CuPc due to the spherical symmetry of C 60 molecules. We observed band bending in C 60 on the standing-up orientation of CuPc molecules, while the energy levels of C 60 on the flat lying orientation of CuPc molecules were observed to be flat. - Highlights: ► Orientation of copper phthalocyanine (CuPc) on ordered graphite and silicon oxide. ► Pinning of lowest unoccupied molecular orbital edge of C60 to the Fermi level on CuPc. ► No C60 pinning or band bending was observed on flat laying CuPc. ► Results are useful for organic photovoltaic and organic light emitting diode research.

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

    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.

  17. Formation and properties of porous silicon layers

    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.)

  18. Whole-Pin Furnace system: An experimental facility for studying irradiated fuel pin behavior under potential reactor accident conditions

    Liu, Y.Y.; Tsai, H.C.; Donahue, D.A.; Pushis, D.O.; Savoie, F.E.; Holland, J.W.; Wright, A.E.; August, C.; Bailey, J.L.; Patterson, D.R.

    1990-05-01

    The whole-pin furnace system is a new in-cell experimental facility constructed to investigate how irradiated fuel pins may fail under potential reactor accident conditions. Extensive checkouts have demonstrated excellent performance in remote operation, temperature control, pin breach detection, and fission gas handling. The system is currently being used in testing of EBIR-II-irradiated Integral Fast Reactor (IFR) metal fuel pins; future testing will include EBR-II-irradiated mixed-oxide fuel pins. 7 refs., 4 figs

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

    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.

  20. Phase-sensitive optical processing in silicon waveguides

    Petermann, Klaus; Gajda, A.; Dziallas, Claudia

    2015-01-01

    Parametric optical signal processing is reviewed for silicon nano-rib-waveguides with a reverse-biased pin-junction. Phase-sensitive parametric amplification with a phase-sensitive extinction of more than 20 dB has been utilized for the regeneration of DPSK signals...

  1. Statistics of dislocation pinning at localized obstacles

    Dutta, A. [S. N. Bose National Centre for Basic Sciences, Salt Lake, Kolkata 700098 (India); Bhattacharya, M., E-mail: mishreyee@vecc.gov.in; Barat, P. [Variable Energy Cyclotron Centre, 1/AF Bidhannagar, Kolkata 700064 (India)

    2014-10-14

    Pinning of dislocations at nanosized obstacles like precipitates, voids, and bubbles is a crucial mechanism in the context of phenomena like hardening and creep. The interaction between such an obstacle and a dislocation is often studied at fundamental level by means of analytical tools, atomistic simulations, and finite element methods. Nevertheless, the information extracted from such studies cannot be utilized to its maximum extent on account of insufficient information about the underlying statistics of this process comprising a large number of dislocations and obstacles in a system. Here, we propose a new statistical approach, where the statistics of pinning of dislocations by idealized spherical obstacles is explored by taking into account the generalized size-distribution of the obstacles along with the dislocation density within a three-dimensional framework. Starting with a minimal set of material parameters, the framework employs the method of geometrical statistics with a few simple assumptions compatible with the real physical scenario. The application of this approach, in combination with the knowledge of fundamental dislocation-obstacle interactions, has successfully been demonstrated for dislocation pinning at nanovoids in neutron irradiated type 316-stainless steel in regard to the non-conservative motion of dislocations. An interesting phenomenon of transition from rare pinning to multiple pinning regimes with increasing irradiation temperature is revealed.

  2. Pinning impulsive control algorithms for complex network

    Sun, Wen [School of Information and Mathematics, Yangtze University, Jingzhou 434023 (China); Lü, Jinhu [Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing 100190 (China); Chen, Shihua [College of Mathematics and Statistics, Wuhan University, Wuhan 430072 (China); Yu, Xinghuo [School of Electrical and Computer Engineering, RMIT University, Melbourne VIC 3001 (Australia)

    2014-03-15

    In this paper, we further investigate the synchronization of complex dynamical network via pinning control in which a selection of nodes are controlled at discrete times. Different from most existing work, the pinning control algorithms utilize only the impulsive signals at discrete time instants, which may greatly improve the communication channel efficiency and reduce control cost. Two classes of algorithms are designed, one for strongly connected complex network and another for non-strongly connected complex network. It is suggested that in the strongly connected network with suitable coupling strength, a single controller at any one of the network's nodes can always pin the network to its homogeneous solution. In the non-strongly connected case, the location and minimum number of nodes needed to pin the network are determined by the Frobenius normal form of the coupling matrix. In addition, the coupling matrix is not necessarily symmetric or irreducible. Illustrative examples are then given to validate the proposed pinning impulsive control algorithms.

  3. Development of a fast pin-by-pin transport solver in ARCADIA registered

    Geemert, R. van

    2009-01-01

    For satisfaction of future global customer needs, dedicated efforts are being coordinated internationally and pursued continuously at AREVA NP. The currently ongoing CONVERGENCE project is committed to the development of the ARCADIA registered next generation core simulation software package. ARCADIA registered will be put to global use by all AREVA NP business regions, for the entire spectrum of core design processes, licensing computations and safety studies. As part of the currently ongoing trend towards more sophisticated neutronics methodologies, an SP 3 nodal transport concept (van Geemert 2008) has been developed for ARTEMIS (Hobson 2008) which is the steady-state and transient core simulation part of ARCADIA registered . For enabling a high computational performance, the SP 3 calculations are accelerated by applying multi-level coarse mesh rebalancing (van Geemert 2006). In the current implementation, SP 3 is typically about 1.4 times as expensive computationally as SP 1 (diffusion). The developed SP 3 solution concept is foreseen as the future computational workhorse for many-group 3D pin-by-pin full core computations by ARCADIA registered . With the entire numerical workload being highly parallelizable through domain decomposition techniques, associated CPU-time requirements that adhere to the efficiency needs in the nuclear industry can be expected to become feasible in the near future. The accuracy enhancement obtainable by using SP 3 instead of SP 1 has been verified by a detailed comparison of ARTEMIS 16-group pin-by-pin SP N results with KAERI's DeCart reference results (Kozlowski 2003) for the 2D pin-by-pin Purdue UO 2 /MOX benchmark. Within the associated pin-by-pin grid, large pin-to-pin variations in cross-section values occur due to the explicit modelling of guide tubes, gadolinium pins as well as the heterogeneous distribution of MOX assemblies and UO 2 assemblies featuring significantly different burnups. With a pin-by-pin grid as

  4. PINS Testing and Modification for Explosive Identification

    Seabury, E.H.; Caffrey, A.J.

    2011-01-01

    The INL's Portable Isotopic Neutron Spectroscopy System (PINS)1 non-intrusively identifies the chemical fill of munitions and sealed containers. PINS is used routinely by the U.S. Army, the Defense Threat Reduction Agency, and foreign military units to determine the contents of munitions and other containers suspected to contain explosives, smoke-generating chemicals, and chemical warfare agents such as mustard and nerve gas. The objects assayed with PINS range from softball-sized M139 chemical bomblets to 200 gallon DOT 500X ton containers. INL had previously examined2 the feasibility of using a similar system for the identification of explosives, and based on this proof-of-principle test, the development of a dedicated system for the identification of explosives in an improvised nuclear device appears entirely feasible. INL has been tasked by NNSA NA-42 Render Safe Research and Development with the development of such a system.

  5. Peripheral pin alignment system for fuel assemblies

    Anthony, A.J.

    1981-01-01

    An alignment system is provided for nuclear fuel assemblies in a nuclear core. The core support structure of the nuclear reactor includes upwardly pointing alignment pins arranged in a square grid and engage peripheral depressions formed in the lateral periphery of the lower ends of each of the fuel assemblies of the core. In a preferred embodiment, the depressions are located at the corners of the fuel assemblies so that each depression includes one-quarter of a cylindrical void. Accordingly, each fuel assembly is positioned and aligned by one-quarter of four separate alignment pins which engage the fuel assemblies at their lower exterior corners. (author)

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

    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.

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

    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

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

    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...

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

    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.

  10. Balanced PIN-TIA photoreceiver with integrated 3 dB fiber coupler for distributed fiber optic sensors

    Datta, Shubhashish; Rajagopalan, Sruti; Lemke, Shaun; Joshi, Abhay

    2014-06-01

    We report a balanced PIN-TIA photoreceiver integrated with a 3 dB fiber coupler for distributed fiber optic sensors. This detector demonstrates -3 dB bandwidth >15 GHz and coupled conversion gain >65 V/W per photodiode through either input port of the 3 dB coupler, and can be operated at local oscillator power of +17 dBm. The combined common mode rejection of the balanced photoreceiver and the integrated 3 dB coupler is >20 dB. We also present measurement results with various optical stimuli, namely impulses, sinusoids, and pseudo-random sequences, which are relevant for time domain reflectometry, frequency domain reflectometry, and code correlation sensors, respectively.

  11. Pinning, flux diodes and ratchets for vortices interacting with conformal pinning arrays

    Olson Reichhardt, C. J.; Wang, Y. L.; Argonne National Laboratory; Xiao, Z. L.; Northern Illinois University, DeKalb, IL

    2016-01-01

    A conformal pinning array can be created by conformally transforming a uniform triangular pinning lattice to produce a new structure in which the six-fold ordering of the original lattice is conserved but where there is a spatial gradient in the density of pinning sites. Here we examine several aspects of vortices interacting with conformal pinning arrays and how they can be used to create a flux flow diode effect for driving vortices in different directions across the arrays. Under the application of an ac drive, a pronounced vortex ratchet effect occurs where the vortices flow in the easy direction of the array asymmetry. When the ac drive is applied perpendicular to the asymmetry direction of the array, it is possible to realize a transverse vortex ratchet effect where there is a generation of a dc flow of vortices perpendicular to the ac drive due to the creation of a noise correlation ratchet by the plastic motion of the vortices. We also examine vortex transport in experiments and compare the pinning effectiveness of conformal arrays to uniform triangular pinning arrays. In conclusion, we find that a triangular array generally pins the vortices more effectively at the first matching field and below, while the conformal array is more effective at higher fields where interstitial vortex flow occurs.

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

    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.)

  13. Design of a terahertz CW photomixer based on PIN and superlattice PIN devices

    Krozer, Viktor; Eichhorn, Finn

    2006-01-01

    We present the design of a photomixer LO based on standard and superlattice PIN diodes, operating at 1 THz. The design is based on a direct integration of a double slot antenna with the PIN device and a suitable matching circuit. The antenna has been designed together with a dielectric lens using...... Ansoft HFSS EM simulation. The large-signal PIN diode model employed in the work has been improved compared to our previously developed model presented earlier in a 3 THz design. We demonstrate that the antenna characteristic changes drastically with the device in place....

  14. Tapered leaf support pin for operating plant guide tubes

    Land, J.T.; Hopkins, R.J.; Ford, D.E.

    1991-01-01

    This patent describes a mounting system for removably mounting the lower flange of a control rod guide tube over an opening in the upper core plate of a nuclear reactor comprising at least one elongated support pin mounted on the guide tube lower flange and resiliently receivable in a bore formed in the upper core plate. It comprises a support pin having a longitudinal axis and comprising a first pin portion mountable on the guide tube lower flange, and a second pin portion receivable within the upper core plate bore, the second pin portion including a solid body section adjacent the first pin portion and having an outer diameter which is accommodated by the bore by a close clearance fit; locking means mounted on the first pin portion of the support pin for retaining the guide tube lower flange between the solid body section of the second pin portion and the locking means; and a washer disposed around the first pin portion between the locking means and the control rod guide tube flange, the washer and the locking means including mutually engaging rounded surfaces for eliminating bending moments and stresses on the support pin during mounting of the locking means on the first pin portion of the support pin

  15. Self-consistent modeling of amorphous silicon devices

    Hack, M.

    1987-01-01

    The authors developed a computer model to describe the steady-state behaviour of a range of amorphous silicon devices. It is based on the complete set of transport equations and takes into account the important role played by the continuous distribution of localized states in the mobility gap of amorphous silicon. Using one set of parameters they have been able to self-consistently simulate the current-voltage characteristics of p-i-n (or n-i-p) solar cells under illumination, the dark behaviour of field-effect transistors, p-i-n diodes and n-i-n diodes in both the ohmic and space charge limited regimes. This model also describes the steady-state photoconductivity of amorphous silicon, in particular, its dependence on temperature, doping and illumination intensity

  16. ASIC Readout Circuit Architecture for Large Geiger Photodiode Arrays

    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.

  17. Characterization of midwave infrared InSb avalanche photodiode

    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.

  18. CMOS-based avalanche photodiodes for direct particle detection

    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

  19. Laser annealing heals radiation damage in avalanche photodiodes

    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.)

  20. Cladding properties under simulated fuel pin transients

    Hunter, C.W.; Johnson, G.D.

    1975-01-01

    A description is given of the HEDL fuel pin testing program utilizing a recently developed Fuel Cladding Transient Tester (FCTT) to generate the requisite mechanical property information on irradiated and unirradiated fast reactor fuel cladding under temperature ramp conditions. The test procedure is described, and data are presented

  1. Turban pin aspiration: new fashion, new syndrome.

    Ilan, Ophir; Eliashar, Ron; Hirshoren, Nir; Hamdan, Kasem; Gross, Menachem

    2012-04-01

    Turban pin aspiration syndrome is a new clinical entity afflicting young Islamic girls wearing a turban.The goal of this study was to present our experience in diagnosis and treatment of this new entity, define its clinical and epidemiologic features, and shed a new light on the role of fashion in the increased incidence. A retrospective study in a tertiary university hospital. Review of clinical parameters and epidemiologic features of 26 patients diagnosed with turban pin aspiration syndrome admitted to the Hadassah-Hebrew University Hospitals in Jerusalem from 1990 to 2010. All patients were Muslim females with an average age of 16 years. In all cases, the history was positive for accidental aspiration. Most of the pins were located in the trachea (42%). In 20 cases, the pins were extracted by rigid bronchoscopy without major complications. Fluoroscopy-assisted rigid bronchoscopy was used successfully in three cases. In one case, the object was self-ejected by coughing before the bronchoscopy, and two patients were referred to the chest unit for thoracotomy. Clinicians should be aware of this distinct form of foreign body aspiration, its method of diagnosis, and extraction techniques. A cultural investigation showed a difference in the turban-fastening technique of young girls as compared with their mothers. Removal by rigid bronchoscopy is a safe method with a high success rate and should be considered as the preferred extraction method of choice. Copyright © 2012 The American Laryngological, Rhinological, and Otological Society, Inc.

  2. Radiographic examination methods for fuel pins

    Smirnov, V.P.; Dvoretskii, V.G.

    1987-11-01

    To study the fast neutron reactor fuel pins structure the NIIAR Institute used x diffraction, neutronic radiography and autoradiographies. The two first methods are used for internal macrostructure studies, the third method for the plutonium and uranium radial distribution. These methods and the main results are indicated in this document [fr

  3. Physicist pins hopes on particle collider

    2007-01-01

    Physicist pins hopes on particle collider By Deseret Morning News Published: Monday, Dec. 31, 27 12:4 a.m. MST FONT Scott Thomas, a 187 State University graduate, is working at the frontiers of science. The theoretical physicist is crafting ways to extract fundamental secrets that seem certain to be uncovered by the Large Hadron Collider.

  4. Analytical method for reconstruction pin to pin of the nuclear power density distribution

    Pessoa, Paulo O.; Silva, Fernando C.; Martinez, Aquilino S., E-mail: ppessoa@con.ufrj.br, E-mail: fernando@con.ufrj.br, E-mail: aquilino@imp.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil)

    2013-07-01

    An accurate and efficient method for reconstructing pin to pin of the nuclear power density distribution, involving the analytical solution of the diffusion equation for two-dimensional neutron energy groups in homogeneous nodes, is presented. The boundary conditions used for analytic as solution are the four currents or fluxes on the surface of the node, which are obtained by Nodal Expansion Method (known as NEM) and four fluxes at the vertices of a node calculated using the finite difference method. The analytical solution found is the homogeneous distribution of neutron flux. Detailed distributions pin to pin inside a fuel assembly are estimated by the product of homogeneous flux distribution by local heterogeneous form function. Furthermore, the form functions of flux and power are used. The results obtained with this method have a good accuracy when compared with reference values. (author)

  5. Analytical method for reconstruction pin to pin of the nuclear power density distribution

    Pessoa, Paulo O.; Silva, Fernando C.; Martinez, Aquilino S.

    2013-01-01

    An accurate and efficient method for reconstructing pin to pin of the nuclear power density distribution, involving the analytical solution of the diffusion equation for two-dimensional neutron energy groups in homogeneous nodes, is presented. The boundary conditions used for analytic as solution are the four currents or fluxes on the surface of the node, which are obtained by Nodal Expansion Method (known as NEM) and four fluxes at the vertices of a node calculated using the finite difference method. The analytical solution found is the homogeneous distribution of neutron flux. Detailed distributions pin to pin inside a fuel assembly are estimated by the product of homogeneous flux distribution by local heterogeneous form function. Furthermore, the form functions of flux and power are used. The results obtained with this method have a good accuracy when compared with reference values. (author)

  6. Pinning control of complex networked systems synchronization, consensus and flocking of networked systems via pinning

    Su, Housheng

    2013-01-01

    Synchronization, consensus and flocking are ubiquitous requirements in networked systems. Pinning Control of Complex Networked Systems investigates these requirements by using the pinning control strategy, which aims to control the whole dynamical network with huge numbers of nodes by imposing controllers for only a fraction of the nodes. As the direct control of every node in a dynamical network with huge numbers of nodes might be impossible or unnecessary, it’s then very important to use the pinning control strategy for the synchronization of complex dynamical networks. The research on pinning control strategy in consensus and flocking of multi-agent systems can not only help us to better understand the mechanisms of natural collective phenomena, but also benefit applications in mobile sensor/robot networks. This book offers a valuable resource for researchers and engineers working in the fields of control theory and control engineering.   Housheng Su is an Associate Professor at the Department of Contro...

  7. PROCOPE, Collision Probability in Pin Clusters and Infinite Rod Lattices

    Amyot, L.; Daolio, C.; Benoist, P.

    1984-01-01

    1 - Nature of physical problem solved: Calculation of directional collision probabilities in pin clusters and infinite rod lattices. 2 - Method of solution: a) Gauss integration of analytical expressions for collision probabilities. b) alternately, an approximate closed expression (not involving integrals) may be used for pin-to-pin interactions. 3 - Restrictions on the complexity of the problem: number of fuel pins must be smaller than 62; maximum number of groups of symmetry is 300

  8. Optimization study on pin tip diameter of an impact-pin nozzle at high pressure ratio

    Kumar, C. Palani; Lee, Kwon Hee [FMTRC, Daejoo Machinery Co. Ltd., Daegu (Korea, Republic of); Park, Tae Choon; Cha, Bong Jun [Engine Components Research Team, Korea Aerospace Research Institute, Daejeon (Korea, Republic of); Kim, Heuy Dong [Dept. of Mechanical Engineering, Andong National University, Andong (Korea, Republic of)

    2016-09-15

    Wet compression system is typically installed in a gas turbine engine to increase the net power output and efficiency. A crucial component of the wet compression system is the nozzle which generates fine water droplets for injection into the compressor. The main objective of present work is to optimize a kind of nozzle called impact-pin spray nozzle and thereby produce better quality droplets. To achieve this, the dynamics occurring in the water jet impinging on the pin tip, the subsequent formation of water sheet, which finally breaks into water droplets, must be studied. In this manuscript, the progress on the numerical studies on impact-pin nozzle are reported. A small computational domain covering the orifice, pin tip and the region where primary atomization occurs is selected for numerical analysis. The governing equations are selected in three dimensional cartesian form and simulations are performed to predict the dynamics of water jet impinging on the pin. Systematic studies were carried out and the results leading to the choice of turbulence model and the effect of pin tip diameter are reported here. Further studies are proposed to show the future directions of the present research work.

  9. A physico-genetic module for the polarisation of auxin efflux carriers PIN-FORMED (PIN)

    Hernández-Hernández, Valeria; Barrio, Rafael A.; Benítez, Mariana; Nakayama, Naomi; Romero-Arias, José Roberto; Villarreal, Carlos

    2018-05-01

    Intracellular polarisation of auxin efflux carriers is crucial for understanding how auxin gradients form in plants. The polarisation dynamics of auxin efflux carriers PIN-FORMED (PIN) depends on both biomechanical forces as well as chemical, molecular and genetic factors. Biomechanical forces have shown to affect the localisation of PIN transporters to the plasma membrane. We propose a physico-genetic module of PIN polarisation that integrates biomechanical, molecular, and cellular processes as well as their non-linear interactions. The module was implemented as a discrete Boolean model and then approximated to a continuous dynamic system, in order to explore the relative contribution of the factors mediating PIN polarisation at the scale of single cell. Our models recovered qualitative behaviours that have been experimentally observed and enable us to predict that, in the context of PIN polarisation, the effects of the mechanical forces can predominate over the activity of molecular factors such as the GTPase ROP6 and the ROP-INTERACTIVE CRIB MOTIF-CONTAINING PROTEIN RIC1.

  10. Primary hip spica with crossed retrograde intramedullary rush pins ...

    Bursitis and penetration of pins at the site of Rush pin insertion is a complication associated with this method of treatment. Conclusion: Closed reduction and internal fixation with crossed Rush pins was a superior treatment method in terms of early weight bearing and restoration of normal anatomy. Keywords: Femoral ...

  11. Some aspects of continuum physics used in fuel pin modeling

    Bard, F.E.

    1975-06-01

    The mathematical formulation used in fuel pin modeling is described. Fuel pin modeling is not a simple extension of the experimental and interpretative methods used in classical mechanics. New concepts are needed to describe materials in a reactor environment. Some aspects of continuum physics used to develop these new constitutive equations for fuel pins are presented. (U.S.)

  12. Post irradiation examination on test fuel pins for PWR

    Fogaca Filho, N.; Ambrozio Filho, F.

    1981-01-01

    Certain aspects of irradiation technology on test fuel pins for PWR, are studied. The results of post irradiation tests, performed on test fuel pins in hot cells, are presented. The results of the tests permit an evaluation of the effects of irradiation on the fuel and cladding of the pin. (Author) [pt

  13. Temperature and pinning strength dependence of the critical current of a superconductor with a square periodic array of pinning sites

    Benkraouda, M.; Obaidat, I.M.; Al Khawaja, U.

    2006-01-01

    We have conducted extensive series of molecular dynamic simulations on driven vortex lattices interacting with periodic square arrays of pinning sites. In solving the over damped equation of vortex motion we took into account the vortex-vortex repulsion interaction, the attractive vortex-pinning interaction, and the driving Lorentz force at several values of temperature. We have studied the effect of varying the driving Lorentz force and varying the pinning strength on the critical current for several pinning densities, and temperature values. We have found that the pinning strength play an important role in enhancing the critical current over the whole temperature range. At low temperatures, the critical current was found to increase linearly with increasing the pinning strengths for all pinning densities. As the temperature increases, the effect of small pinning strengths diminishes and becomes insignificant at high temperatures

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

    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.

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

    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

  16. 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

    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

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

    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.

  18. Al{sub 0.2}Ga{sub 0.8}As X-ray photodiodes for X-ray spectroscopy

    Whitaker, M.D.C., E-mail: M.Whitaker@sussex.ac.uk; Lioliou, G.; Butera, S.; Barnett, A.M.

    2016-12-21

    Three custom-made Al{sub 0.2}Ga{sub 0.8}As p-i-n mesa X-ray photodiodes (200 µm diameter, 3 µm i layer) were electrically characterised and investigated for their response to illumination with soft X-rays from an {sup 55}Fe radioisotope X-ray source (Mn Kα = 5.9 keV; Mn Kβ = 6.49 keV). The AlGaAs photodiodes were shown to be suitable for photon counting X-ray spectroscopy at room temperature. When coupled to a custom-made low-noise charge-sensitive preamplifier, a mean energy resolution (as quantified by the full width at half maximum of the 5.9 keV photopeak) of 1.24 keV was measured at room temperature. Parameters such as the depletion width (1.92 µm at 10 V), charge trapping noise (61.7 e{sup −} rms ENC at 5 V, negligible at 10 V) and the electronic noise components (known dielectric noise (63.4 e{sup −} rms), series white noise (27.7 e{sup −} rms), parallel white noise (9.5 e{sup −} rms) and 1/f series noise (2.2 e{sup −} rms) at 10 V reverse bias) affecting the achieved energy resolution were computed. The estimated charge trapping noise and mean energy resolution were compared to similar materials (e.g. Al{sub 0.8}Ga{sub 0.2}As) previously reported, and discussed. These results are the first demonstration of photon counting X-ray spectroscopy with Al{sub 0.2}Ga{sub 0.8}As reported to date.

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

    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.

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

    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.

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

    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)

  2. Pinning impulsive synchronization of stochastic delayed coupled networks

    Tang Yang; Fang Jian-An; Wong W K; Miao Qing-Ying

    2011-01-01

    In this paper, the pinning synchronization problem of stochastic delayed complex network (SDCN) is investigated by using a novel hybrid pinning controller. The proposed hybrid pinning controller is composed of adaptive controller and impulsive controller, where the two controllers are both added to a fraction of nodes in the network. Using the Lyapunov stability theory and the novel hybrid pinning controller, some sufficient conditions are derived for the exponential synchronization of such dynamical networks in mean square. Two numerical simulation examples are provided to verify the effectiveness of the proposed approach. The simulation results show that the proposed control scheme has a fast convergence rate compared with the conventional adaptive pinning method. (general)

  3. Compact silicon photonic resonance-sssisted variable optical attenuator.

    Wang, Xiaoxi; Aguinaldo, Ryan; Lentine, Anthony; DeRose, Christopher; Starbuck, Andrew L; Trotter, Douglas; Pomerene, Andrew; Mookherjea, Shayan

    2016-11-28

    A two-part silicon photonic variable optical attenuator is demonstrated in a compact footprint which can provide a high extinction ratio at wavelengths between 1520 nm and 1620 nm. The device was made by following the conventional p-i-n waveguide section by a high-extinction-ratio second-order microring filter section. The rings provide additional on-off contrast by utilizing a thermal resonance shift, which harvested the heat dissipated by current injection in the p-i-n junction. We derive and discuss a simple thermal-resistance model in explanation of these effects.

  4. 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)

    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.

  5. The pin pixel detector--neutron imaging

    Bateman, J E; Derbyshire, G E; Duxbury, D M; Marsh, A S; Rhodes, N J; Schooneveld, E M; Simmons, J E; Stephenson, R

    2002-01-01

    The development and testing of a neutron gas pixel detector intended for application in neutron diffraction studies is reported. Using standard electrical connector pins as point anodes, the detector is based on a commercial 100 pin connector block. A prototype detector of aperture 25.4 mmx25.4 mm has been fabricated, giving a pixel size of 2.54 mm which matches well to the spatial resolution typically required in a neutron diffractometer. A 2-Dimensional resistive divide readout system has been adapted to permit the imaging properties of the detector to be explored in advance of true pixel readout electronics. The timing properties of the device match well to the requirements of the ISIS-pulsed neutron source.

  6. Elementary pinning force for a superconducting vortex

    Hyun, O.B.; Finnemore, D.K.; Schwartzkopf, L.; Clem, J.R.

    1987-01-01

    The elementary pinning force f/sub p/ has been measured for a single vortex trapped in one of the superconducting layers of a cross-strip Josephson junction. At temperatures close to the transition temperature the vortex can be pushed across the junction by a transport current. The vortex is found to move in a small number of discrete steps before it exits the junction. The pinning force for each site is found to be asymmetric and to have a value of about 10/sup -6/ N/m at the reduced temperature, t = T/T/sub c/ = 0.95. As a function of temperature, f/sub p/ is found to vary approximately as (1-t)/sup 3/2/. .AE

  7. Top-nozzle mounted replacement guide pin assemblies

    Gilmore, C.B.; Andrews, W.H.

    1993-01-01

    A replacement guide pin assembly is provided for aligning a nuclear fuel assembly with an upper core plate of a nuclear reactor core. The guide pin assembly includes a guide pin body having a radially expandable base insertable within a hole in the top nozzle, a ferrule insertable within the guide pin base and capable of imparting a radially and outwardly directed force on the expandable base to expand it within the hole of the top nozzle and thereby secure the guide pin body to the top nozzle in response to a predetermined displacement of the ferrule relative to the guide pin body along its longitudinal axis, and a lock screw interfitted with the ferrule and threaded into the guide pin body so as to produce the predetermined displacement of the ferrule. (author)

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

    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)

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

    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.

  10. Timing analysis of PWR fuel pin failures

    Jones, K.R.; Wade, N.L.; Katsma, K.R.; Siefken, L.J.; Straka, M.

    1992-09-01

    Research has been conducted to develop and demonstrate a methodology for calculation of the time interval between receipt of the containment isolation signals and the first fuel pin failure for loss-of-coolant accidents (LOCAs). Demonstration calculations were performed for a Babcock and Wilcox (B ampersand W) design (Oconee) and a Westinghouse (W) four-loop design (Seabrook). Sensitivity studies were performed to assess the impacts of fuel pin bumup, axial peaking factor, break size, emergency core cooling system availability, and main coolant pump trip on these times. The analysis was performed using the following codes: FRAPCON-2, for the calculation of steady-state fuel behavior; SCDAP/RELAP5/MOD3 and TRACPF1/MOD1, for the calculation of the transient thermal-hydraulic conditions in the reactor system; and FRAP-T6, for the calculation of transient fuel behavior. In addition to the calculation of fuel pin failure timing, this analysis provides a comparison of the predicted results of SCDAP/RELAP5/MOD3 and TRAC-PFL/MOD1 for large-break LOCA analysis. Using SCDAP/RELAP5/MOD3 thermal-hydraulic data, the shortest time intervals calculated between initiation of containment isolation and fuel pin failure are 10.4 seconds and 19.1 seconds for the B ampersand W and W plants, respectively. Using data generated by TRAC-PF1/MOD1, the shortest intervals are 10.3 seconds and 29.1 seconds for the B ampersand W and W plants, respectively. These intervals are for a double-ended, offset-shear, cold leg break, using the technical specification maximum peaking factor and applied to fuel with maximum design bumup. Using peaking factors commensurate widi actual bumups would result in longer intervals for both reactor designs. This document also contains appendices A through J of this report

  11. New KID dosemeter for measurement of cosmic dosimetry

    Peksova, D.; Kakona, M.; Krist, P.; Kocur, Z.; Larina, K. V.; Ploc, O.

    2018-01-01

    The KID dosemeter is a small semiconductor low-power detector developed for common use. The current design is special designed after measuring cosmic rays on aircraft decks. The design concept is the same world-class devices Internet of Things (IoT). As a detection element detector were tested three variants a) PIN HAMAMATSU S2744-09 photodiode, b) 9 parallel Vishay photodiodes TEMD5080X01, c) 16 Vishay photodiode TEMD5080X01 again in parallel connection. All variants are silicon PIN photodiode. (authors)

  12. Performance measurements of hybrid PIN diode arrays

    Jernigan, J.G.; Arens, J.F.; Collins, T.; Herring, J.; Shapiro, S.L.; Wilburn, C.D.

    1990-05-01

    We report on the successful effort to develop hybrid PIN diode arrays and to demonstrate their potential as components of vertex detectors. Hybrid pixel arrays have been fabricated by the Hughes Aircraft Co. by bump bonding readout chips developed by Hughes to an array of PIN diodes manufactured by Micron Semiconductor Inc. These hybrid pixel arrays were constructed in two configurations. One array format having 10 x 64 pixels, each 120 μm square, and the other format having 256 x 256 pixels, each 30 μm square. In both cases, the thickness of the PIN diode layer is 300 μm. Measurements of detector performance show that excellent position resolution can be achieved by interpolation. By determining the centroid of the charge cloud which spreads charge into a number of neighboring pixels, a spatial resolution of a few microns has been attained. The noise has been measured to be about 300 electrons (rms) at room temperature, as expected from KTC and dark current considerations, yielding a signal-to-noise ratio of about 100 for minimum ionizing particles. 4 refs., 13 figs

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

    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

  14. Silicon Qubits

    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.

  15. Three-Terminal Amorphous Silicon Solar Cells

    Cheng-Hung Tai

    2011-01-01

    Full Text Available Many defects exist within amorphous silicon since it is not crystalline. This provides recombination centers, thus reducing the efficiency of a typical a-Si solar cell. A new structure is presented in this paper: a three-terminal a-Si solar cell. The new back-to-back p-i-n/n-i-p structure increased the average electric field in a solar cell. A typical a-Si p-i-n solar cell was also simulated for comparison using the same thickness and material parameters. The 0.28 μm-thick three-terminal a-Si solar cell achieved an efficiency of 11.4%, while the efficiency of a typical a-Si p-i-n solar cell was 9.0%. Furthermore, an efficiency of 11.7% was achieved by thickness optimization of the three-terminal solar cell.

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

    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.

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

    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

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

    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.

  19. Applicability of the diffusion and simplified P3 theories for BWR pin-by-pin core analysis

    Tada, Kenichi; Yamamoto, Akio; Kitamura, Yasunori; Yamane, Yoshihiro; Watanabe, Masato; Noda, Hiroshi

    2007-01-01

    The pin-by-pin fine mesh core calculation method is considered as a candidate of next-generation core calculation method for BWR. In this study, the diffusion and the simplified P 3 (SP 3 ) theories are applied to the pin-by-pin core analysis of BWR. Performances of the diffusion and the SP 3 theories for cell-homogeneous pin-by-pin fine mesh BWR core analysis are evaluated through comparison with cell-heterogeneous detailed transport calculation by the method of characteristics (MOC). In this study, two-dimensional, 2x2 multi-assemblies geometry is used to compare the prediction accuracies of the diffusion and the SP 3 theories. The 2x2 multi- assemblies geometry consists of two types of 9x9 UO 2 assembly that have two different enrichment splittings. To mitigate the cell-homogenization error, the SPH method is applied for the pin-by-pin fine mesh calculation. The SPH method is a technique that reproduces a result of heterogeneous calculation by that of homogeneous calculation. The calculation results indicated that diffusion theory shows larger discrepancy than that of SP 3 theory on pin-wise fission rates. Furthermore, the accuracy of the diffusion theory would not be sufficient for the pin-by-pin fine mesh calculation. In contrast to the diffusion theory, the SP 3 theory shows much better accuracy on pin wise fission rates. Therefore, if the SP 3 theory is applied, the accuracy of the pin-by-pin fine mesh BWR core analysis will be higher and will be sufficient for production calculation. (author)

  20. Silicon Pixel Detectors for Synchrotron Applications

    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...

  1. Abrasive Wear Resistance of Tool Steels Evaluated by the Pin-on-Disc Testing

    Bressan, José Divo; Schopf, Roberto Alexandre

    2011-05-01

    Present work examines tool steels abrasion wear resistance and the abrasion mechanisms which are one main contributor to failure of tooling in metal forming industry. Tooling used in cutting and metal forming processes without lubrication fails due to this type of wear. In the workshop and engineering practice, it is common to relate wear resistance as function of material hardness only. However, there are others parameters which influences wear such as: fracture toughness, type of crystalline structure and the occurrence of hard precipitate in the metallic matrix and also its nature. In the present investigation, the wear mechanisms acting in tool steels were analyzed and, by normalized tests, wear resistance performance of nine different types of tool steels were evaluated by pin-on-disc testing. Conventional tool steels commonly used in tooling such as AISI H13 and AISI A2 were compared in relation to tool steels fabricated by sintering process such as Crucible CPM 3V, CPM 9V and M4 steels. Friction and wear testing were carried out in a pin-on-disc automated equipment which pin was tool steel and the counter-face was a abrasive disc of silicon carbide. Normal load of 5 N, sliding velocity of 0.45 m/s, total sliding distance of 3000 m and room temperature were employed. The wear rate was calculated by the Archard's equation and from the plotted graphs of pin cumulated volume loss versus sliding distance. Specimens were appropriately heat treated by quenching and three tempering cycles. Percentage of alloying elements, metallographic analyses of microstructure and Vickers microhardness of specimens were performed, analyzed and correlated with wear rate. The work is concluded by the presentation of a rank of tool steel wear rate, comparing the different tool steel abrasion wear resistance: the best tool steel wear resistance evaluated was the Crucible CPM 9V steel.

  2. Gamma Large Area Silicon Telescope (GLAST)

    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

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

    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

  4. A proposed parameterization of interface discontinuity factors depending on neighborhood for pin-by-pin diffusion computations for LWR

    Herrero, Jose Javier; Garcia-Herranz, Nuria; Ahnert, Carol

    2011-01-01

    There exists an interest in performing full core pin-by-pin computations for present nuclear reactors. In such type of problems the use of a transport approximation like the diffusion equation requires the introduction of correction parameters. Interface discontinuity factors can improve the diffusion solution to nearly reproduce a transport solution. Nevertheless, calculating accurate pin-by-pin IDF requires the knowledge of the heterogeneous neutron flux distribution, which depends on the boundary conditions of the pin-cell as well as the local variables along the nuclear reactor operation. As a consequence, it is impractical to compute them for each possible configuration. An alternative to generate accurate pin-by-pin interface discontinuity factors is to calculate reference values using zero-net-current boundary conditions and to synthesize afterwards their dependencies on the main neighborhood variables. In such way the factors can be accurately computed during fine-mesh diffusion calculations by correcting the reference values as a function of the actual environment of the pin-cell in the core. In this paper we propose a parameterization of the pin-by-pin interface discontinuity factors allowing the implementation of a cross sections library able to treat the neighborhood effect. First results are presented for typical PWR configurations. (author)

  5. A proposed parameterization of interface discontinuity factors depending on neighborhood for pin-by-pin diffusion computations for LWR

    Herrero, Jose Javier; Garcia-Herranz, Nuria; Ahnert, Carol, E-mail: herrero@din.upm.es, E-mail: nuria@din.upm.es, E-mail: carol@din.upm.es [Departamento de Ingenieria Nuclear, Universidad Politecnica de Madrid (Spain)

    2011-07-01

    There exists an interest in performing full core pin-by-pin computations for present nuclear reactors. In such type of problems the use of a transport approximation like the diffusion equation requires the introduction of correction parameters. Interface discontinuity factors can improve the diffusion solution to nearly reproduce a transport solution. Nevertheless, calculating accurate pin-by-pin IDF requires the knowledge of the heterogeneous neutron flux distribution, which depends on the boundary conditions of the pin-cell as well as the local variables along the nuclear reactor operation. As a consequence, it is impractical to compute them for each possible configuration. An alternative to generate accurate pin-by-pin interface discontinuity factors is to calculate reference values using zero-net-current boundary conditions and to synthesize afterwards their dependencies on the main neighborhood variables. In such way the factors can be accurately computed during fine-mesh diffusion calculations by correcting the reference values as a function of the actual environment of the pin-cell in the core. In this paper we propose a parameterization of the pin-by-pin interface discontinuity factors allowing the implementation of a cross sections library able to treat the neighborhood effect. First results are presented for typical PWR configurations. (author)

  6. Genome-wide identification and evolution of the PIN-FORMED (PIN) gene family in Glycine max.

    Liu, Yuan; Wei, Haichao

    2017-07-01

    Soybean (Glycine max) is one of the most important crop plants. Wild and cultivated soybean varieties have significant differences worth further investigation, such as plant morphology, seed size, and seed coat development; these characters may be related to auxin biology. The PIN gene family encodes essential transport proteins in cell-to-cell auxin transport, but little research on soybean PIN genes (GmPIN genes) has been done, especially with respect to the evolution and differences between wild and cultivated soybean. In this study, we retrieved 23 GmPIN genes from the latest updated G. max genome database; six GmPIN protein sequences were changed compared with the previous database. Based on the Plant Genome Duplication Database, 18 GmPIN genes have been involved in segment duplication. Three pairs of GmPIN genes arose after the second soybean genome duplication, and six occurred after the first genome duplication. The duplicated GmPIN genes retained similar expression patterns. All the duplicated GmPIN genes experienced purifying selection (K a /K s genome sequence of 17 wild and 14 cultivated soybean varieties. Our research provides useful and comprehensive basic information for understanding GmPIN genes.

  7. Simulation of Silicon Photomultiplier Signals

    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.

  8. Robustness of pinning a general complex dynamical network

    Wang Lei; Sun Youxian

    2010-01-01

    This Letter studies the robustness problem of pinning a general complex dynamical network toward an assigned synchronous evolution. Several synchronization criteria are presented to guarantee the convergence of the pinning process locally and globally by construction of Lyapunov functions. In particular, if a pinning strategy has been designed for synchronization of a given complex dynamical network, then no matter what uncertainties occur among the pinned nodes, synchronization can still be guaranteed through the pinning. The analytical results show that pinning control has a certain robustness against perturbations on network architecture: adding, deleting and changing the weights of edges. Numerical simulations illustrated by scale-free complex networks verify the theoretical results above-acquired.

  9. Is magnetic pinning a dominant mechanism in Nb-Ti

    Cooley, L.D.; Lee, P.J.; Larbalestier, D.C.

    1991-01-01

    In this paper, the authors compare the pinning behavior of an artificial pinning center (APC) composite and a nanometer-filament Nb 46.5 wt% Ti composite to that of a conventional Nb 48 wt% Ti composite. The microstructure of the APC composite resembles the conventional composite, where ribbons of normal metal form the pinning centers, whereas the nanometer-filament composite has no internal normal metal but pins instead at the filament surface. The APC composite exhibits much stronger pinning relative to B c 2 than the conventional composite (21.4 GN/m 3 , 7 T vs. 18.9 GN/m 3 , 11 T), which is possibly due to the increased amount of pinning center (50 vol.% vs. 25 vol.%), however the proximity effect reduces the B c 2 unfavorably

  10. Ferromagnetic artificial pinning centers in multifilamentary superconducting wires

    Wang, J.Q.; Rizzo, N.D.; Prober, D.E.

    1997-01-01

    The authors fabricated multifilamentary NbTi wires with ferromagnetic (FM) artificial pinning centers (APCs) to enhance the critical current density (J c ) in magnetic fields. They used a bundle and draw technique to process the APC wires with either Ni or Fe as the pinning centers. Both wires produced higher J c in the high field range (5-9 T) than previous non-magnetic APC wires similarly processed, even though the authors have not yet optimized pin percentage. Using a magnetometer they found that the pins remained ferromagnetic for the wires with maximum J c . However, they did observe a substantial loss of FM material for the wires where the pin diameter approached 3 nm. Thus, they expect further enhancement of J c with better pin quality

  11. Correlation of creep and swelling with fuel pin performance

    Jackson, R.J.; Washburn, D.F.; Garner, F.A.; Gilbert, E.R.

    1975-09-01

    The HEDL PNL-11 experiment described was one in a series of fueled subassemblies irradiated in EBR-II to demonstrate the adequacy of the FFTF fuel pin design. The cladding material, dimensions, and fuel density are prototypic of FFTF. Because neutron flux in EBR-II is lower than in FFTF, the uranium enrichment is higher in these experimental fuel pins, irradiated in EBR-II, than the FFTF enrichment for comparable linear heat rates. Some pertinent oprating conditions for the center fuel pin in this experiment are listed. This 37-pin subassembly represents, at 110,000 MWd/MTM, the highest burnup yet attained by a prototypic FFTF subassembly. Similarly, this is the highest fluence presently attained by prototypic fuel pins. A cladding breach occurred in one fuel pin which is presently being examined. Results are presented and discussed

  12. Analysis of three idealized reactor configurations: plate, pin, and homogeneous

    McKnight, R.D.

    1983-01-01

    Detailed Monte Carlo calculations have been performed for three distinct configurations of an idealized fast critical assembly. This idealized assembly was based on the LMFBR benchmark critical assembly ZPR-6/7. In the first configuration, the entire core was loaded with the plate unit cell of ZPR-6/7. In the second configuration, the entire core was loaded with the ZPR sodium-filled pin calandria. The actual ZPR pin calandria are loaded with mixed (U,Pu) oxide pins which closely match the composition of the ZPR-6/7 plate unit cell. For the present study, slight adjustments were made in the atom concentrations and the length of the pin calandria in order to make the core boundaries and average composition for the pin-cell configuration identical to those of the plate-cell configuration. In the third configuration, the core was homogeneous, again with identical core boundaries and average composition as the plate and pin configurations

  13. Analytic models for fuel pin transient performance

    Bard, F.E.; Fox, G.L.; Washburn, D.F.; Hanson, J.E.

    1976-09-01

    HEDL's ability to analyze various mechanisms that operate within a fuel pin has progressed substantially through development of codes such as PECTCLAD, which solves cladding response, and DSTRESS, which solves fuel response. The PECTCLAD results show good correlation with a variety of mechanical tests on cladding material and also demonstrate the significance of cladding strength when applying the life fraction rule. The DSTRESS results have shown that fuel deforms sufficiently during overpower transient tests that available volumes are filled, whether in the form of a central cavity or start-up cracks

  14. Optimum Prestress of Tanks with Pinned Base

    Brøndum-Nielsen, Troels

    1998-01-01

    Amin Ghali and Eleanor Elliott presented in their paper an interesting suggestion for prestressing of circular tanks without sliding joints. For many prestressed tanks the following construction procedure is adopted:In order to ensure compressive hoop forces in the wall near the base, the wall...... is allowed to slide freely in the radial direction during tensioning (free base).After tensioning such displacements are prevented (pinned base). The present paper addresses the problem of prestress of such tanks.Keywords: circular prestressing; creep properties; prestressed concrete; redistribution...

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

    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.

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

    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.

  17. On the obstructions to non-Cliffordian pin structures

    Chamblin, A. (Dept. of Applied Maths and Theoretical Physics, Univ. of Cambridge (United Kingdom))

    1994-07-01

    We derive the topological obstructions to the existence of non-Cliffordian pin structures on four-dimensional spacetimes. We apply these obstructions to the study of non-Cliffordian pin-Lorentz cobordism. We note that our method of derivation applies equally well in any dimension and in any signature, and we present a general format for calculating obstructions in these situations. Finally, we interpret the breakdown of pin structure and discuss the relevance of this to aspects of physics. (orig.)

  18. Sodium erosion of boron carbide from breached absorber pins

    Basmajian, J.A.; Baker, D.E.

    1981-03-01

    The purpose of the irradiation experiment was to provide an engineering demonstration of the irradiation behavior of breached boron carbide absorber pins. By building defects into the cladding of prototypic absorber pins, and performing the irradiation under typical FFTF operating conditions, a qualitative assessment of the consequences of a breach was achieved. Additionally, a direct comparison of pin behavior with that of the ex-reactor test could be made

  19. Cell homogenization methods for pin-by-pin core calculations tested in slab geometry

    Yamamoto, Akio; Kitamura, Yasunori; Yamane, Yoshihiro

    2004-01-01

    In this paper, performances of spatial homogenization methods for fuel or non-fuel cells are compared in slab geometry in order to facilitate pin-by-pin core calculations. Since the spatial homogenization methods were mainly developed for fuel assemblies, systematic study of their performance for the cell-level homogenization has not been carried out. Importance of cell-level homogenization is recently increasing since the pin-by-pin mesh core calculation in actual three-dimensional geometry, which is less approximate approach than current advanced nodal method, is getting feasible. Four homogenization methods were investigated in this paper; the flux-volume weighting, the generalized equivalence theory, the superhomogenization (SPH) method and the nonlinear iteration method. The last one, the nonlinear iteration method, was tested as the homogenization method for the first time. The calculations were carried out in simplified colorset assembly configurations of PWR, which are simulated by slab geometries, and homogenization performances were evaluated through comparison with the reference cell-heterogeneous calculations. The calculation results revealed that the generalized equivalence theory showed best performance. Though the nonlinear iteration method can significantly reduce homogenization error, its performance was not as good as that of the generalized equivalence theory. Through comparison of the results obtained by the generalized equivalence theory and the superhomogenization method, important byproduct was obtained; deficiency of the current superhomogenization method, which could be improved by incorporating the 'cell-level discontinuity factor between assemblies', was clarified

  20. Development of 3D pseudo pin-by-pin calculation methodology in ANC

    Zhang, B.; Mayhue, L.; Huria, H.; Ivanov, B.

    2012-01-01

    Advanced cores and fuel assembly designs have been developed to improve operational flexibility, economic performance and further enhance safety features of nuclear power plants. The simulation of these new designs, along with strong heterogeneous fuel loading, have brought new challenges to the reactor physics methodologies currently employed in the industrial codes for core analyses. Control rod insertion during normal operation is one operational feature in the AP1000 R plant of Westinghouse next generation Pressurized Water Reactor (PWR) design. This design improves its operational flexibility and efficiency but significantly challenges the conventional reactor physics methods, especially in pin power calculations. The mixture loading of fuel assemblies with significant neutron spectrums causes a strong interaction between different fuel assembly types that is not fully captured with the current core design codes. To overcome the weaknesses of the conventional methods, Westinghouse has developed a state-of-the-art 3D Pin-by-Pin Calculation Methodology (P3C) and successfully implemented in the Westinghouse core design code ANC. The new methodology has been qualified and licensed for pin power prediction. The 3D P3C methodology along with its application and validation will be discussed in the paper. (authors)

  1. Trending on Pinterest: an examination of pins about skin tanning.

    Banerjee, Smita C; Rodríguez, Vivian M; Greene, Kathryn; Hay, Jennifer L

    2018-04-10

    Rates of melanoma and nonmelanoma skin cancers are on the rise in the USA with data revealing disproportionate increase in female young adults. The popularity of intentional skin tanning among U.S. adolescents is attributed to several factors, including prioritization of physical appearance, media images of tanned celebrities, ease of availability of artificial tanning facilities, and more recently, the prevalence and celebration of tanned skin on social media. Pinterest, as the third most popular social media platform, was searched for "pins" about skin tanning. The resultant "pins" were examined to understand the extent and characteristics of skin tanning portrayed on Pinterest. We analyzed pins on Pinterest about skin tanning (n = 501) through a quantitative content analysis. Overall, results indicated an overwhelmingly protanning characteristic of pins about skin tanning on Pinterest, with over 85% of pins promoting tanning behavior. The pins were generally characterized by the portrayal of a female subject (61%) and provided positive reinforcement for tanning (49%). Use of tanning for enhancing appearance was the main positive outcome expectancy portrayed in the pins (35%), and nudity or exposure of skin on arms (32%) and legs (31%) was evident in about a third of pins. With overwhelmingly positive pins promoting tanning, use of female subjects, exhibiting nudity, and appearance enhancement, there seems be to a consistent targeting of female users to accept tanning as a socially acceptable and popular behavior. The findings indicate a need for developing sun protection messages and the leveraging of social media for dissemination of skin cancer prevention and detection messages.

  2. The pin pixel detector--X-ray imaging

    Bateman, J E; Derbyshire, G E; Duxbury, D M; Marsh, A S; Simmons, J E; Stephenson, R

    2002-01-01

    The development and testing of a soft X-ray gas pixel detector, which uses connector pins for the anodes is reported. Based on a commercial 100 pin connector block, a prototype detector of aperture 25.4 mm centre dot 25.4 mm can be economically fabricated. The individual pin anodes all show the expected characteristics of small gas detectors capable of counting rates reaching 1 MHz per pin. A 2-dimensional resistive divide readout system has been developed to permit the imaging properties of the detector to be explored in advance of true pixel readout electronics.

  3. Reconstruction calculation of pin power for ship reactor core

    Li Haofeng; Shang Xueli; Chen Wenzhen; Wang Qiao

    2010-01-01

    Aiming at the limitation of the software that pin power distribution for ship reactor core was unavailable, the calculation model and method of the axial and radial pin power distribution were proposed. Reconstruction calculations of pin power along axis and radius was carried out by bicubic and bilinear interpolation and cubic spline interpolation, respectively. The results were compared with those obtained by professional reactor physical soft with fine mesh difference. It is shown that our reconstruction calculation of pin power is simple and reliable as well as accurate, which provides an important theoretic base for the safety analysis and operating administration of the ship nuclear reactor. (authors)

  4. Vortex pinning landscape in MOD-TFA YBCO nanostroctured films

    Gutierrez, J.; Puig, T.; Pomar, A.; Obradors, X.

    2008-03-01

    A methodology of general validity to study vortex pinning in YBCO based on Jc transport measurements is described. It permits to identify, separate and quantify three basic vortex pinning contributions associated to anisotropic-strong, isotropic-strong and isotropic-weak pinning centers. Thereof, the corresponding vortex pinning phase diagrams are built up. This methodology is applied to the new solution-derived YBCO nanostructured films, including controlled interfacial pinning by the growth of nanostructured templates by means of self-assembled processes [1] and YBCO-BaZrO3 nanocomposites prepared by modified solution precursors. The application of the methodology and comparison with a standard solution-derived YBCO film [2], enables us to identify the nature and the effect of the additional pinning centers induced. The nanostructured templates films show c-axis pinning strongly increased, controlling most of the pinning phase diagram. On the other hand, the nanocomposites have achieved so far, the highest pinning properties in HTc-superconductors [3], being the isotropic-strong defects contribution the origin of their unique properties. [1] M. Gibert et al, Adv. Mat. vol 19, p. 3937 (2007) [2] Puig.T et al, SuST EUCAS 2007 (to be published) [3] J. Gutierrez et al, Nat. Mat. vol. 6, p. 367 (2007) * Work supported by HIPERCHEM, NANOARTIS and MAT2005-02047

  5. ITP Hanford Type 40 pin electrical connector failure analysis

    Imrich, K.J.

    1993-01-01

    Corrosion products observed on the ITP Hanford Type 40 pin electrical connectors would be expected to adversely affect the power and control signals supplied to process equipment in the filter cell by the connectors. Corrosion products were consistent with those found on similar pins in DWPF. The recommendations based on the findings in this investigation are as follows: (1) Replace male and female rhodium plated pins with gold plated pins. (2) Replace the galvanized carbon steel spring on the male connector with a stainless steel spring. (3) Install protective caps over Hanford connectors when jumpers are removed

  6. Fuel-pin cladding transient failure strain criterion

    Bard, F.E.; Duncan, D.R.; Hunter, C.W.

    1983-01-01

    A criterion for cladding failure based on accumulated strain was developed for mixed uranium-plutonium oxide fuel pins and used to interpret the calculated strain results from failed transient fuel pin experiments conducted in the Transient Reactor Test (TREAT) facility. The new STRAIN criterion replaced a stress-based criterion that depends on the DORN parameter and that incorrectly predicted fuel pin failure for transient tested fuel pins. This paper describes the STRAIN criterion and compares its prediction with those of the stress-based criterion

  7. Dynamic Phases of Vortices in Superconductors with Periodic Pinning

    Reichhardt, C.; Olson, C.; Nori, F.

    1997-01-01

    We present results from extensive simulations of driven vortex lattices interacting with periodic arrays of pinning sites. Changing an applied driving force produces a rich variety of novel dynamical plastic flow phases which are very distinct from those observed in systems with random pinning arrays. Signatures of the transition between these different dynamical phases include sudden jumps in the current-voltage curves as well as marked changes in the vortex trajectories and vortex lattice order. Several dynamical phase diagrams are obtained as a function of commensurability, pinning strength, and spatial order of the pinning sites. copyright 1997 The American Physical Society

  8. Positioning and locking device for fuel pin to grid attachment

    Frick, T.M.; Wineman, A.L.

    1976-01-01

    A positioning and locking device for fuel pin to grid attachment provides an inexpensive means of positively positioning and locking the individual fuel pins which make up the driver fuel assemblies used in nuclear reactors. The device can be adapted for use with a currently used attachment grid assembly design and insures that the pins remain in their proper position throughout the in-reactor life of the assembly. This device also simplifies fuel bundle assembly in that a complete row of fuel pins can be added to the bundle during each step of assembly. 8 claims, 8 drawing figures

  9. Heat transfer in a fuel pin shipping container

    Ingham, J.G.

    1980-01-01

    Maximum cladding temperatures occur when the IDENT 1578 fuel pin shipping container is installed in the T-3 Cask. The maximum allowable cladding temperature of 800 0 F is reached when the rate of energy deposited in the 19-pin basket reaches 400 watts. Since 45% of the energy which is generated in the fuel escapes the 19-pin basket without being deposited, mostly gamma energy, the maximum allowable rate of heat generation is 400/.55 = 727 watts. Similarly, the maximum allowable cladding temperature of 800 0 F is reached when the rate of energy deposited in the 40-pin basket reaches 465 watts. Since 33% of the energy which is generated in the fuel escapes the 40-pin basket without being deposited, mostly gamma energy, the maximum allowable rate of heat generation is 465/.66 = 704 watts. The IDENT 1578 fuel pin shipping container therefore meets its thermal design criteria. IDENT 1578 can handle fuel pins with a decay heat load of 600 watts while maintaining the maximum fuel pin cladding temperature below 800 0 F. The emissivities which were determined from the test results for the basket tubes and container are relatively low and correspond to new, shiny conditions. As the IDENT 1578 container is exposed to high temperatures for extended periods of time during the transportation of fuel pins, the emissivities will probably increase. This will result in reduced temperatures

  10. Nano-engineered pinning centres in YBCO superconducting films

    Crisan, A., E-mail: adrian.crisan@infim.ro [National Institute for Materials Physics Bucharest, 105 bis Atomistilor Str., 077125 Magurele (Romania); School of Metallurgy and Materials, University of Birmingham, Edgbaston, B15 2TT Birmingham (United Kingdom); Dang, V.S. [School of Metallurgy and Materials, University of Birmingham, Edgbaston, B15 2TT Birmingham (United Kingdom); Nano and Energy Center, VNU Hanoi University of Science, 334 Nguyen Trai, Thanh Xuan, Hanoi (Viet Nam); Mikheenko, P. [School of Metallurgy and Materials, University of Birmingham, Edgbaston, B15 2TT Birmingham (United Kingdom); Department of Physics, University of Oslo, P.O. Box 1048 Blindern, N-0316 Oslo (Norway)

    2017-02-15

    Highlights: • Power applications of YBCO films/coated conductors in technological relevant magnetic fields requires nano-engineered pinning centre. • Three approaches have been proposed: substrate decoration, quasi-multilayers, and targets with secondary phase nano-inclusions. • Combination of all three approaches greatly increased critical current in YBCO films. • Bulk pinning force, pinning potential, and critical current density are estimated and discussed in relation with the type and strength of pinning centres related to the defects evidenced by Transmission Electron Microscopy. - Abstract: For practical applications of superconducting materials in applied magnetic fields, artificial pinning centres in addition to natural ones are required to oppose the Lorentz force. These pinning centres are actually various types of defects in the superconductor matrix. The pinning centres can be categorised on their dimension (volume, surface or point) and on their character (normal cores or Δκ cores). Different samples have been produced by Pulsed Laser Deposition, with various thicknesses, temperatures and nanostructured additions to the superconducting matrix. They have been characterized by SQUID Magnetic Properties Measurement System and Physical Properties Measurement System, as well as by Transmission Electron Microscopy (TEM). Correlations between pinning architecture, TEM images, and critical currents at various fields and field orientations will be shown for a large number of YBa{sub 2}Cu{sub 3}O{sub x} films with various types and architectures of artificial pinning centres.

  11. Prototype for the measurement of parameters in the Mammography Unity using photodiodes; Prototipo para la medicion de parametros en una Unidad de Mamografia utilizando fotodiodos

    Mercado H, I.; Ramirez J, F.J.; Tovar M, V.; Becerril V, A. [Instituto Nacional de Investigaciones Nucleares, Salazar, Estado de Mexico C.P. 52045 (Mexico)

    1999-07-01

    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 {mu} 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)

  12. Accelerated stress testing of amorphous silicon solar cells

    Stoddard, W. G.; Davis, C. W.; Lathrop, J. W.

    1985-01-01

    A technique for performing accelerated stress tests of large-area thin a-Si solar cells is presented. A computer-controlled short-interval test system employing low-cost ac-powered ELH illumination and a simulated a-Si reference cell (seven individually bandpass-filtered zero-biased crystalline PIN photodiodes) calibrated to the response of an a-Si control cell is described and illustrated with flow diagrams, drawings, and graphs. Preliminary results indicate that while most tests of a program developed for c-Si cells are applicable to a-Si cells, spurious degradation may appear in a-Si cells tested at temperatures above 130 C.

  13. FABRICE process for the refrabrication of experimental pins in a hot cell, from pins pre-irradiated in power reactors

    Vignesoult, N.; Atabek, R.; Ducas, S.

    1982-06-01

    The Fabrice ''hot cell refabrication'' process for small pins from very long irradiated fuel elements was developed at the CEA to allow parametric studies of the irradiation behavior of pins from nuclear power plants. Since this operation required complete assurance of the validity of the process, qualification of the fabrication was performed on test pins, refabricated in the hot cell, as well as irradiation qualification. The latter qualification was intended to demonstrate that, in identical experimental irradiation conditions, the refabricated Fabrice pins behaved in the same way as whole pins with the same initial characteristics. This qualification of the Fabrice process, dealing with more than twenty pins at different burnups, showed that fabrication did not alter: the inherent characteristics of the sampled fuel element and the irradiation behavior of the sampled fuel element [fr

  14. Passivation of MBE grown InGaSb/InAs superlattice photodiodes

    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.

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

    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

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

    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...

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

    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.

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

    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

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

    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

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

    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.

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

    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

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

    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),

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

    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

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

    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.

  5. Material accountancy for metallic fuel pin casting

    Bucher, R.G.; Orechwa, Y.; Beitel, J.C.

    1995-01-01

    The operation of the Fuel Conditioning Facility (FCF) is based on the electrometallurgical processing of spent metallic reactor fuel. The pin casting operation, although only one of several operations in FCF, was the first to be on-line. As such, it has served to demonstrate the material accountancy system in many of its facets. This paper details, for the operation of the pin casting process with depleted uranium, the interaction between the mass tracking system (MTG) and some of the ancillary computer codes which generate pertinent information for operations and material accountancy. It is necessary to distinguish between two types of material balance calculations -- closeout for operations and material accountancy for safeguards. The two have much in common, for example, the mass tracking system database and the calculation of an inventory difference, but, in general, are not congruent with regard to balance period and balance spatial domain. Moreover, the objective, assessment, and reporting requirements of the calculated inventory difference are very different in the two cases

  6. The Egyptian Hair Pin: practical, sacred, fatal

    Joann Fletcher

    2016-11-01

    Full Text Available Generally regarded as little more than a mundane tool employed in daily life, the humble hairpin occasionally played a rather more prominent role in history than has perhaps been appreciated. As the most ancient implements associated with hair styling, simple pins of bone and ivory were commonly employed in Egypt by c.4000 BC as a means of securing long hair in an upswept style (e.g. Petrie and Mace 1901, 21, 34. Although their occasional use by men undermines the assumption that hairpins are 'a relatively certain example of a “gendered” artefact' (Wilfong 1997, 67, the vast majority have been found in female burials. They can be made of bone and ivory, wood, steatite, glass, gold, silver and bronze, and two 12cm long bronze examples were found within the hair of Princess Ahmosi c.1550 BC (Fletcher 1995, 376, 441 while the hair of an anonymous woman at Gurob c.AD 110 had been secured in a bun with pins of bone, tortoiseshell and silver (Walker and Bierbrier 1997, 209.

  7. Method and device for cleaning fuel pins

    Matsumoto, Kaname; Oohigashi, Yoshiaki.

    1985-01-01

    Purpose: To remove clads or scales deposited on the outer surface of fuel pins in BWR type reactors. Method: A fuel assembly taken out of a reactor core is vertically contained without detaching a channel box in a scrubber tower disposed in a liquid tight manner within a fuel pool. Then, a specifically prepared slurry is caused to flow and uprise from the bottom of the scrubber tower into the channel box and then discharged from the top of the tower. The slurry is prepared by mixing pure water and granules (for example, as activated carbon, ion exchanger resin, iron and molecular sieve) of such a granular size as not causing clogging in the channel box of the fuel assembly and having a larger specific gravity than pure water. The slurry flown into the channel box scrubs the surface of fuel pins to scrape off clads or scales. Then, discharged slurry is sent to a hydraulic cyclone to separate the granules from the clads or scales. (Ikeda, J.)

  8. Lightning Pin Injection Testing on MOSFETS

    Ely, Jay J.; Nguyen, Truong X.; Szatkowski, George N.; Koppen, Sandra V.; Mielnik, John J.; Vaughan, Roger K.; Wysocki, Philip F.; Celaya, Jose R.; Saha, Sankalita

    2009-01-01

    Lightning transients were pin-injected into metal-oxide-semiconductor field-effect transistors (MOSFETs) to induce fault modes. This report documents the test process and results, and provides a basis for subsequent lightning tests. MOSFETs may be present in DC-DC power supplies and electromechanical actuator circuits that may be used on board aircraft. Results show that unprotected MOSFET Gates are susceptible to failure, even when installed in systems in well-shielded and partial-shielded locations. MOSFET Drains and Sources are significantly less susceptible. Device impedance decreased (current increased) after every failure. Such a failure mode may lead to cascading failures, as the damaged MOSFET may allow excessive current to flow through other circuitry. Preliminary assessments on a MOSFET subjected to 20-stroke pin-injection testing demonstrate that Breakdown Voltage, Leakage Current and Threshold Voltage characteristics show damage, while the device continues to meet manufacturer performance specifications. The purpose of this research is to develop validated tools, technologies, and techniques for automated detection, diagnosis and prognosis that enable mitigation of adverse events during flight, such as from lightning transients; and to understand the interplay between lightning-induced surges and aging (i.e. humidity, vibration thermal stress, etc.) on component degradation.

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

    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.

  10. Radiation effects on breakdown in silicon multiguarded diodes

    Bisello, D.; Da Rold, M.; Franzin, L.; Wheadon, R.

    1996-01-01

    The authors have investigated the current-voltage characteristics of silicon PIN diodes with a number of different multiguard structures. These structures were designed to increase the overall device breakdown voltage. The same measurements were carried out after gamma irradiation at different doses and neutron irradiation at fluences beyond type-inversion. This study is a first step towards defining guard structures optimized for operation in high-radiation environments such as those expected at the LHC

  11. Minimum ionizing particle detection using amorphous silicon diodes

    Xi, J.; Hollingsworth, R.E.; Buitrago, R.H. (Glasstech Solar, Inc., Wheat Ridge, CO (USA)); Oakley, D.; Cumalat, J.P.; Nauenberg, U. (Colorado Univ., Boulder (USA). Dept. of Physics); McNeil, J.A. (Colorado School of Mines, Golden (USA). Dept. of Physics); Anderson, D.F. (Fermi National Accelerator Lab., Batavia, IL (USA)); Perez-Mendez, V. (Lawrence Berkeley Lab., CA (USA))

    1991-03-01

    Hydrogenated amorphous silicon pin diodes have been used to detect minimum ionizing electrons with a pulse height signal-to-noise ratio exceeding 3. A distinct signal was seen for shaping times from 100 to 3000 ns. The devices used had a 54 {mu}m thick intrinsic layer and an active area of 0.1 cm{sup 2}. The maximum signal was 3200 electrons with a noise width of 950 electrons for a shaping time of 250 ns. (orig.).

  12. BARS - a heterogeneous code for 3D pin-by-pin LWR steady-state and transient calculation

    Avvakumov, A.V.; Malofeev, V.M.

    2000-01-01

    A 3D pin-by-pin dynamic model for LWR detailed calculation was developed. The model is based on a coupling of the BARS neutronic code with the RELAP5/MOD3.2 thermal hydraulic code. This model is intended to calculate a fuel cycle, a xenon transient, and a wide range of reactivity initiated accidents in a WWER and a PWR. Galanin-Feinberg heterogeneous method was realized in the BARS code. Some results for a validation of the heterogeneous method are presented for reactivity coefficients, a pin-by-pin power distribution, and a fast pulse transient. (Authors)

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

    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

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

    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.

  15. Amorphous silicon pixel radiation detectors and associated thin film transistor electronics readout

    Perez-Mendez, V.; Cho, G.; Drewery, J.; Jing, T.; Kaplan, S.N.; Mireshghi, A.; Wildermuth, D.; Goodman, C.; Fujieda, I.

    1992-07-01

    We describe the characteristics of thin (1 μm) and thick (> 30 μm) hydrogenated amorphous silicon p-i-n diodes which are optimized for detecting and recording the spatial distribution of charged particles, x-ray, γ rays and thermal neutrons. For x-ray, γ ray, and charged particle detection we can use thin p-i-n photosensitive diode arrays coupled to evaporated layers of suitable scintillators. For thermal neutron detection we use thin (2∼5 μm) gadolinium converters on 30 μm thick a-Si:H diodes. For direct detection of minimum ionizing particles and others with high resistance to radiation damage, we use the thick p-i-n diode arrays. Diode and amorphous silicon readouts as well as polysilicon pixel amplifiers are described

  16. Gamma and Proton-Induced Dark Current Degradation of 5T CMOS Pinned Photodiode 0.18 mu{m} CMOS Image Sensors

    Martin, E.; Nuns, T.; David, J.-P.; Gilard, O.; Vaillant, J.; Fereyre, P.; Prevost, V.; Boutillier, M.

    2014-02-01

    The radiation tolerance of a 0.18 μm technology CMOS commercial image sensor has been evaluated with Co60 and proton irradiations. The effects of protons on the hot pixels and dynamic bias and duty cycle conditions during gamma irradiations are studied.

  17. Pinning in BSCCO above the ordinary irreversibility line

    Indenbom, M. V.; van der Beek, C. J.; Berseth, V.; Konczykowski, M.; Motohira, N.; Berger, H.; Benoit, W.

    1996-12-01

    Frequency-dependent observations of magnetic flux structures are used to show that pinning plays a principal role in the whole mixed state in Bi2Sr2CaCu2O8 (BSCCO) single crystals. We speculate that the random pinning force on the moving vortices may dominate over thermal fluctuations and considerably modify the position of the vortex lattice phase transition.

  18. Inscuteable Regulates the Pins-Mud Spindle Orientation Pathway

    Mauser, Jonathon F.; Prehoda, Kenneth E.

    2012-01-01

    During asymmetric cell division, alignment of the mitotic spindle with the cell polarity axis ensures that the cleavage furrow separates fate determinants into distinct daughter cells. The protein Inscuteable (Insc) is thought to link cell polarity and spindle positioning in diverse systems by binding the polarity protein Bazooka (Baz; aka Par-3) and the spindle orienting protein Partner of Inscuteable (Pins; mPins or LGN in mammals). Here we investigate the mechanism of spindle orientation by the Insc-Pins complex. Previously, we defined two Pins spindle orientation pathways: a complex with Mushroom body defect (Mud; NuMA in mammals) is required for full activity, whereas binding to Discs large (Dlg) is sufficient for partial activity. In the current study, we have examined the role of Inscuteable in mediating downstream Pins-mediated spindle orientation pathways. We find that the Insc-Pins complex requires Gαi for partial activity and that the complex specifically recruits Dlg but not Mud. In vitro competition experiments revealed that Insc and Mud compete for binding to the Pins TPR motifs, while Dlg can form a ternary complex with Insc-Pins. Our results suggest that Insc does not passively couple polarity and spindle orientation but preferentially inhibits the Mud pathway, while allowing the Dlg pathway to remain active. Insc-regulated complex assembly may ensure that the spindle is attached to the cortex (via Dlg) before activation of spindle pulling forces by Dynein/Dynactin (via Mud). PMID:22253744

  19. IMp: The customizable LEGO(®) Pinned Insect Manipulator.

    Dupont, Steen; Price, Benjamin; Blagoderov, Vladimir

    2015-01-01

    We present a pinned insect manipulator (IMp) constructed of LEGO® building bricks with two axes of movement and two axes of rotation. In addition we present three variants of the IMp to emphasise the modular design, which facilitates resizing to meet the full range of pinned insect specimens, is fully customizable, collapsible, affordable and does not require specialist tools or knowledge to assemble.

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

    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

  1. Geochemistry of silicon isotopes

    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.

  2. Cracking Bank PINs by Playing Mastermind

    Focardi, Riccardo; Luccio, Flaminia L.

    The bank director was pretty upset noticing Joe, the system administrator, spending his spare time playing Mastermind, an old useless game of the 70ies. He had fought the instinct of telling him how to better spend his life, just limiting to look at him in disgust long enough to be certain to be noticed. No wonder when the next day the director fell on his chair astonished while reading, on the newspaper, about a huge digital fraud on the ATMs of his bank, with millions of Euros stolen by a team of hackers all around the world. The article mentioned how the hackers had 'played with the bank computers just like playing Mastermind', being able to disclose thousands of user PINs during the one-hour lunch break. That precise moment, a second before falling senseless, he understood the subtle smile on Joe's face the day before, while training at his preferred game, Mastermind.

  3. The lumped parameter model for fuel pins

    Liu, W S [Ontario Hydro, Toronto, ON (Canada)

    1996-12-31

    The use of a lumped fuel-pin model in a thermal-hydraulic code is advantageous because of computational simplicity and efficiency. The model uses an averaging approach over the fuel cross section and makes some simplifying assumptions to describe the transient equations for the averaged fuel, fuel centerline and sheath temperatures. It is shown that by introducing a factor in the effective fuel conductivity, the analytical solution of the mean fuel temperature can be modified to simulate the effects of the flux depression in the heat generation rate and the variation in fuel thermal conductivity. The simplified analytical method used in the transient equation is presented. The accuracy of the lumped parameter model has been compared with the results from the finite difference method. (author). 4 refs., 2 tabs., 4 figs.

  4. Effective augmentation of networked systems and enhancing pinning controllability

    Jalili, Mahdi

    2018-06-01

    Controlling dynamics of networked systems to a reference state, known as pinning control, has many applications in science and engineering. In this paper, we introduce a method for effective augmentation of networked systems, while also providing high levels of pinning controllability for the final augmented network. The problem is how to connect a sub-network to an already existing network such that the pinning controllability is maximised. We consider the eigenratio of the augmented Laplacian matrix as a pinning controllability metric, and use graph perturbation theory to approximate the influence of edge addition on the eigenratio. The proposed metric can be effectively used to find the inter-network links connecting the disjoint networks. Also, an efficient link rewiring approach is proposed to further optimise the pinning controllability of the augmented network. We provide numerical simulations on synthetic networks and show that the proposed method is more effective than heuristic ones.

  5. Artificial pinning center technology to enhance vortex pinning in YBCO coated conductors

    Matsumoto, Kaname; Mele, Paolo

    2010-01-01

    Crystalline defects on the nano-scale, which are called artificial pinning centers (APCs), were successfully introduced into high-temperature superconductors (HTS) by nanotechnology, in order to strongly pin the quantized vortices. The critical current densities, J c , of the HTS films were dramatically improved by APCs. It is possible to form APCs in high-quality epitaxial films, keeping the desired dimensionality, volume fraction, spatial distribution and so on. The in-field J c of HTS films at 77 K was improved by one order of magnitude compared with previous values using APCs. This technology can be applied to the coated conductor technology in progress, and a high J c has already been reported. A current outline of the research is described in this review.

  6. Retractable Pin Tools for the Friction Stir Welding Process

    1998-01-01

    Two companies have successfully commercialized a specialized welding tool developed at the Marshall Space Flight Center (MSFC). Friction stir welding uses the high rotational speed of a tool and the resulting frictional heat created from contact to crush, 'stir' together, and forge a bond between two metal alloys. It has had a major drawback, reliance on a single-piece pin tool. The pin is slowly plunged into the joint between two materials to be welded and rotated as high speed. At the end of the weld, the single-piece pin tool is retracted and leaves a 'keyhole,' something which is unacceptable when welding cylindrical objects such as drums, pipes and storage tanks. Another drawback is the requirement for different-length pin tools when welding materials of varying thickness. An engineer at the MSFC helped design an automatic retractable pin tool that uses a computer-controlled motor to automatically retract the pin into the shoulder of the tool at the end of the weld, preventing keyholes. This design allows the pin angle and length to be adjusted for changes in material thickness and results in a smooth hole closure at the end of the weld. Benefits of friction stir welding, using the MSFC retractable pin tool technology, include the following: The ability to weld a wide range of alloys, including previously unweldable and composite materials; provision of twice the fatigue resistance of fusion welds and no keyholes; minimization of material distortion; no creation of hazards such as welding fumes, radiation, high voltage, liquid metals, or arcing; automatic retraction of the pin at the end of the weld; and maintaining full penetration of the pin.

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

    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

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

    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

  9. A pinning puzzle: two similar, non-superconducting chemical deposits in YBCO-one pins, the other does not

    Sawh, Ravi-Persad; Weinstein, Roy; Gandini, Alberto; Skorpenske, Harley; Parks, Drew, E-mail: Weinstein@uh.ed [Beam Particle Dynamics Laboratories, University of Houston, Houston, TX 77204-5005 (United States); Department of Physics, University of Houston, Houston, TX 77204-5005 (United States); Texas Center for Superconductivity at UH, University of Houston, Houston, TX 77204-5002 (United States)

    2009-09-15

    The pinning effects of two kinds of U-rich deposits in YBCO (YBa{sub 2}Cu{sub 3}O{sub 7-{delta}}) are compared. One is a five-element compound, (U{sub 0.6}Pt{sub 0.4})YBa{sub 2}O{sub 6}, which is a paramagnetic double perovskite which forms as profuse stable nanosize deposits, and pins very well. The other is a four-element compound, (U{sub 0.4}Y{sub 0.6})BaO{sub 3}, which is a ferromagnetic single perovskite which forms as profuse stable nanosize deposits and pins very weakly or not at all. The pinning comparison is done with nearly equal deposit sizes and number of deposits per unit volume for the two compounds. Evidence for the pinning capability, chemical makeup, x-ray diffraction signature, and magnetic properties of the two compounds is reported.

  10. Geneva University - Silicon photomultiplier : features and applications

    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...

  11. Improved SPICE electrical model of silicon photomultipliers

    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.

  12. Low power frontend ASIC (Anusuchak) for dosimeter using Si-PIN detector

    Darad, A.; Chandratre, V.B.

    2010-01-01

    A low power ASIC (Anusuchak) for silicon PIN detector signal processing channel designed for pocket dosimeter in 0.35 μm CMOS process. The ASIC contains two channels one for Beta particle and other for Gamma ray. The channel is a CSA integrated with a shaper, gain stage and comparator with total power consumption of 4.6 mW. The ASIC has gain of 12 mV/fC and can be raised to 29 mV/fC without degrading the noise, power or linearity specification of the channel. The channel has a peaking time of 1.2 μs with baseline recovery within 5.3 μs and noise figure of 420 e- at 0 pF. The noise slope is 17 e-/pF. The ASIC is designed for single supply of 3.3 V for which battery is available. (author)

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

    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.

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

    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...

  15. Use of Peltier cells in high resolution alpha spectrometry

    Bueno, C.C.; Santos, M.D.S.; Goncalves, J.A.C.

    1994-01-01

    The experiments with low-cost commercial silicon PIN photodiodes have shown the possibility of their transformation for use as alpha detectors with performance comparable with surface barrier detectors which are more expensive. Utilizing the silicon photodiode with reverse bias, an energy resolution for 241 Am alpha particles of 28 KeV and 23 KeV were obtained at room temperature and at -30 0 C respectively. (author). 4 refs, 4 figs

  16. Surface passivation of GaInAsSb photodiodes with thioacetamide

    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.)

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

    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

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

    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

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

    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.

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

    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.