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3w Transmitted Beam Diagnostic at the Omega Laser Facility

Description: A 3{omega} transmitted beam diagnostic has been commissioned on the Omega Laser at the Laboratory for Laser Energetics, University of Rochester [Soures et.al., Laser Part. Beams 11 (1993)]. Transmitted light from one beam is collected by a large focusing mirror and directed onto a diagnostic platform. The near field of the transmitted light is imaged; the system collects information from twice the original f-cone of the beam. Two gated optical cameras capture the near field image of the transmitted light. Thirteen spatial positions around the measurement region are temporally resolved using fast photodiodes to allow a measure of the beam spray evolution. The Forward stimulated Raman scattering and forward simulated Brillion scattering are spectrally and temporally resolved at 5 independent locations within twice the original f-cone. The total transmitted energy is measured in two spectral bands ({delta}{lambda} < 400 nm and {delta}{lambda} > 400 nm).
Date: April 24, 2006
Creator: Froula, D H; Rekow, V; Sorce, C; Piston, K; Knight, R; Alvarez, S et al.
Partner: UNT Libraries Government Documents Department

Global optical lightning flash rates determined with the Forte satellite

Description: Using FORTE photodiode detector (PDD) observations of lightning, we have determined the geographic distribution of nighttime flash rate density. We estimate the PDD flash detection efficiency to be 62% for total lightning through comparison to lightning observations by the TRMM satellite's Lightning Imaging Sensor (LIS), using cases in which FORTE and TRMM viewed the same storm. We present here both seasonal and l,ot,al flash rate maps. We examine some characteristics of the optical emissions of lightning in both high and low flash rate environments, and find that while lightning occurs less frequently over ocean, oceanic lightning flashes are somewhat more powerful, on average, than those over land.
Date: January 1, 2003
Creator: Light, T. (Tracy E.); Davis, S. M. (Sean M.); Boeck, W. L. (William L.); Jacobson, A. R. & Suszcynsky, D. M. (David M.)
Partner: UNT Libraries Government Documents Department

Fiber positioning and MRS response

Description: This paper provides experimental results on the dependence of the output signal from small-area silicon photodetectors, such as MRS (Metal-Resistive layer-Semiconductor) photodiodes, on the fiber alignment.
Date: May 18, 2004
Creator: al., Pavel Polozov et
Partner: UNT Libraries Government Documents Department

The Status of Thermophotovoltaic Energy Conversion Technology at Lockheed Martin Corp.

Description: In a thermophotovoltaic (TPV) energy conversion system, a heated surface radiates in the mid-infrared range onto photodiodes which are sensitive at these energies. Part of the absorbed energy is converted into electric output. Conversion efficiency is maximized by reducing the absorption of non-convertible energy with some form of spectral control. In a TPV system, many technology options exist. The development efforts have concentrated on flat-plate geometries with greybody radiators, low bandgap quaternary diodes, front surface tandem filters and a multi-chip module (MCM) approach that allows selective fabrication processes to match diode performance. Recently, the authors achieved conversion efficiencies of about 20% (radiator 950 C, diodes 22 C) for a module in a prototypic cavity test environment. These tests employed InGaAsSb diodes with 0.52 eV bandgap and front surface filters for spectral control. This paper provides details of the individual system components and describes the measurement technique used to record these efficiencies.
Date: January 31, 2003
Creator: Brown, E.J.; Baldasaro, P.F.; Burger, S.R.; Danielson, L.R.; DePoy, D.M.; Nichols, G.J. et al.
Partner: UNT Libraries Government Documents Department

AlGaN UV LED and Photodiodes Radiation Hardness and Space Qualifications and Their Applications in Space Science and High Energy Density Physics

Description: This presentation provides an overview of robust, radiation hard AlGaN optoelectronic devices and their applications in space exploration & high energy density physics. Particularly, deep UV LED and deep UV photodiodes are discussed with regard to their applications, radiation hardness and space qualification. AC charge management of UV LED satellite payload instruments, which were to be launched in late 2012, is covered.
Date: May 31, 2011
Creator: Sun, K. X.
Partner: UNT Libraries Government Documents Department

Direct x-ray response of self-scanning photodiode arrays

Description: Self-scanning photodiode arrays were tested for their ability to measure the spatial distribution of low-energy x rays in a wavelength-dispersive spectrometer. X-ray spectral sensitivity was measured with a calibrated dc source of nearly-monochromatic characteristic-x rays with photon energies in the range of 1.5 to 8 keV. Photodiode response was found to be linear with x-ray flux. Exposure to large doses of copper radiation did not affect sensitivity. A mathematical model that describes the experimental data is presented. It was found that spatial resolving power was lowered by the dispersal of photogenerated charges. This effect was investigated with collimated beams and is described with a formula that predicts the loss of diode signals. (auth)
Date: August 13, 1975
Creator: Koppel, L. N.
Partner: UNT Libraries Government Documents Department

Final report on LDRD project 52722 : radiation hardened optoelectronic components for space-based applications.

Description: This report describes the research accomplishments achieved under the LDRD Project 'Radiation Hardened Optoelectronic Components for Space-Based Applications.' The aim of this LDRD has been to investigate the radiation hardness of vertical-cavity surface-emitting lasers (VCSELs) and photodiodes by looking at both the effects of total dose and of single-event upsets on the electrical and optical characteristics of VCSELs and photodiodes. These investigations were intended to provide guidance for the eventual integration of radiation hardened VCSELs and photodiodes with rad-hard driver and receiver electronics from an external vendor for space applications. During this one-year project, we have fabricated GaAs-based VCSELs and photodiodes, investigated ionization-induced transient effects due to high-energy protons, and measured the degradation of performance from both high-energy protons and neutrons.
Date: December 1, 2003
Creator: Hargett, Terry W. (L&M Technologies, Inc.); Serkland, Darwin Keith; Blansett, Ethan L.; Geib, Kent Martin; Sullivan, Charles Thomas; Hawkins, Samuel D. et al.
Partner: UNT Libraries Government Documents Department

Neutron Bang Time Detector Based on a Light Pipe

Description: A neutron bang time detector consisting of a scintillator, light pipe, photomultiplier tube (PMT), and high-bandwidth oscilloscope has been implemented on the 60-beam, 30-kJ OMEGA Laser Facility at the University of Rochester's Laboratory for Laser Energetics. Light from the scintillator, located 23 cm from the target, is transmitted outside the target bay through a 9.6-m-long, 2-in.-diam polished stainless steel pipe to the PMT. The PMT signal is recorded by two channels of a 6-GHz, 10-GS/s Tektronix 6604 oscilloscope. The OMEGA optical fiducial pulse train is recorded on the third oscilloscope channel using a fast photodiode to provide the timing reference to the laser. The bang-time detector is absolutely calibrated in time and is able to measure bang time for neutron yields above 1 x 10{sup 9} with accuracy of better than 25 ps.
Date: May 8, 2008
Creator: Glebov, V Y; Moran, M; Stoeckl, C; Sangster, T C & Cruz, M
Partner: UNT Libraries Government Documents Department

Time-resolved Temperature Measurements in SSPX

Description: We seek to measure time-resolved electron temperatures in the SSPX plasma using soft X-rays from free-free Bremsstrahlung radiation. To increase sensitivity to changes in temperature over the range 100-300 eV, we use two photodiode detectors sensitive to different soft X-ray energies. The detectors, one with a Zr/C coating and the other with a Ti/Pd coating, view the plasma along a common line of sight tangential to the magnetic axis of the spheromak, where the electron temperature is a maximum. The comparison of the signals, over a similar volume of plasma, should be a stronger function of temperature than a single detector in the range of Te< 300 eV. The success of using photodiodes to detect changing temperatures along a chord will make the case for designing an array of the detectors, which could provide a time changing temperature profile over a larger portion of the plasma.
Date: August 14, 2006
Creator: Ludington, A R; Hill, D N; McLean, H S; Moller, J & Wood, R D
Partner: UNT Libraries Government Documents Department

Laser Timing Jitter Measurements using a Dual-Sweep Streak Camera at the A0 Photoinjector

Description: Excellent phase stability of the drive laser is a critical performance specification of photoinjectors such as Fermilab's A0 photoinjector (A0PI). Previous efforts based on the measurement of the power spectrum of the signal of a fast photodiode illuminated by the mode locked infrared laser pulse component indicated a phase jitter of less than 1.4 ps (technique limited). A recently procured dual sweep plugin unit and existing Hamamatsu C5680 streak camera were used to study the phase stability of the UV laser pulse component. Initial measurements with the synchroscan vertical sweep unit locked to 81.25 MHz showed that the phase slew through the micropulse train and the phase jitter micropulse to micropulse were two key aspects that could be evaluated. The phase slew was much less than 100 fs per micropulse, and the total phase jitter (camera, trigger, and laser) was approximately 300 fs RMS for measurements of 50-micropulse trains. Data on the macropulse phase stability were also obtained. A possible upgrade to achieve better phase stability will be also discussed.
Date: April 30, 2009
Creator: Ruan, J.; Lumpkin, A.H.; Santucci, J.K. & /Fermilab
Partner: UNT Libraries Government Documents Department

Nuclear and electronic energy loss by 1 keV to 60 keV ions in silicon : comparison of measurement to SRIM

Description: Comparison of TRIM simulations with measurements of the energy lost to electronic and nuclear stopping processes using 1 00% internal carrier collection efficiency silicon photodiodes shows a large, systematic overestimation by TRIM of electronic energy loss.
Date: January 1, 2003
Creator: Funsten, H. O. (Herbert O.); Harper, R. W. (Ronnie W.); Ritzau, S. M. (Stephen M.) & Korde, R. (Raj)
Partner: UNT Libraries Government Documents Department

Measurement of the hybrid photodiode response - Fiber optic window

Description: The hybrid photodiode (HPD[1]) will be used for the CMS HCAL readout [2]. A fiber-optic front window is used to reduce optical cross-talk between the pixels of the multi-pixel HPD�s. A mismatch of numerical aperture between optical fibers carrying light to the HPD window and the fibers composing the fiber-optic front window of the HPD could lead to light loss. The light loss would appear as a reduced effective quantum efficiency of the device. The goal of this set of measurements was to see if there was in fact a reduction in the effective quantum efficiency of the HPD�s.
Date: January 1, 1999
Creator: Ronzhin, A.; Green, D.; Freeman, J. & Barbaro, P. de
Partner: UNT Libraries Government Documents Department

Spectral correction of silicon photodiode solar radiation detectors

Description: The multi-filter rotating shadowband radiometer (MFRSR) is a ground- based instrument that uses a silicon photodiode sensor to measure shortwave global and diffuse horizontal irradiance from which direct normal irradiance is calculated. Besides this multiplexing advantage, silicon sensors are rugged, stable and have a fast time response. On the other hand, silicon sensors are both thermally and spectrally sensitive. They, as do all pyranometric sensors, have an imperfect cosine response, especially at high solar-zenith angles. In the MFRSR two of these problems are solved. The MFRSR`s cosine response is measured and corrected. An automatic heater maintains the MFRSR detector at a constant temperature near 40 {degree}C. This paper describes a correction scheme, based on sky conditions, to account for the remaining spectral bias. The data base for these corrections was collected in Albany, New York, during 1993. The MFRSR and WMO firstclass thermopile instruments were sampled every 15 seconds and 5- minute averages were compared. The differences in time response between silicon and thermopile instruments contributes substantially to the remaining root-mean-square error reported.
Date: December 31, 1994
Creator: Zhou, C. & Michalsky, J.
Partner: UNT Libraries Government Documents Department

Test of the DEP hybrid photodiode in 5 Tesla Magnet

Description: The CMS detector is designed so that the tile/fiber hadronic calorimeter (HCAL) is immersed in a 4 Tesla magnetic field. The Hybrid Photodiode (HPD) will be used as the photodetector. Below we present the experiment data which we obtained on the HPD behavior in a magnetic field.
Date: October 1, 1997
Creator: Green, D; Freeman, J.; Ronzhin, A.; Cushman, R. & Heering, A.
Partner: UNT Libraries Government Documents Department

Test of DEP hybrid photodiodes

Description: The goal of the measurement was to study some parameters of DEP HYBRID PHOTODIODES (HPD), and the check its performance for CMS calorimetry at LHC. The principal of the HPD operation is described. The schematic view of the HPD. The HPD is vacuum photo device composed of photocathode (PC) and a silicon PIN diode (Si) as multiplication system in a very close proximity geometry. The distance between PC and Si is of the order of several mm and has an electric field < 10 kV. The photoelectron emited by the photocathode multiply by a factor of several thousand in the silicon and the charge is collected on the HPD`s anode. Several types of HPD`s were tested. There was a single channel HPD, called {open_quotes}E-type{close_quotes} with p-side of the silicon facing the HPD`s photocathode and two multipixel HPD (DEP) namely a 25 pixel HPD and a 7 pixel HPD. Both were of {open_quotes}T-type{close_quotes} structure with n-side of silicon facing the photocathode.
Date: August 1, 1997
Creator: Baumbaugh, A.; Binkley, M. & Elias, J.
Partner: UNT Libraries Government Documents Department

[SSC subsystem proposal for pre-shower and Shower Maximum Detectors]. Final report

Description: The basic purpose of this project was to devise low-cost photodetectors and arrays with large dynamic range capable of high-rate, radiation-resistant operation in multi-TeV hadron colliders. This project`s particular application was changed from the Superconducting Super Collider`s SDC detector to the Large Hadron Collider`s CMS after the Superconducting Super Collider project was cancelled. This report describes development and testing of photodetectors, and contains both a table summarizing the properties of different photodetectors and a paper on the performance of an avalanche photodiode photomultiplier tube tested at the CERN PS.
Date: December 31, 1994
Partner: UNT Libraries Government Documents Department

Evaluation of 1024 channel VUV-photo-diodes for soft x-ray diagnostic applications

Description: We tested the operation of 1024 channel diode arrays (Model AXUV-1024, from IRD, Inc.) in subdued room light to establish that they worked and to determine the direction and speed of the scan of the 1024 channels. Further tests were performed in vacuum in the HAP, High-Average-Power Facility. There we found that the bare or glass covered diodes detected primarily visible light as expected, but diodes filtered by aluminized parylene, produced a signal consistent with soft x-rays. It is probable that the spectral response and sensitivity, as discussed below, reproduce that previously demonstrated by 1 to 16 channel VUV-photodiodes; however, significantly more effort would be required to establish that experimentally. These detectors appear to be worth further evaluation where 25 w spatial resolution bolometers or spectrograph detectors of known sensitivity are required, and single-shot or 0.02-0.2s time response is adequate. (Presumably, faster readout would be available with custom drive circuitry.)
Date: April 25, 1997
Creator: Molvik, A. W.
Partner: UNT Libraries Government Documents Department

Improved accuracy for low-cost solar irradiance sensors

Description: Accurate measurements of broadband (full spectrum) solar irradiance are fundamental to the successful implementation of solar power systems, both photovoltaic and solar thermal. Historically, acceptable measurement accuracy has been achieved using expensive thermopile-based pyranometers and pyrheliometers. The measurement limitations and sensitivities of these expensive radiometers are a topic that has been addressed elsewhere. This paper demonstrates how to achieve acceptable accuracy ({+-}3) in irradiance measurements using photodiodes or photovoltaic cells as sensors, and in addition to low-cost, have several operational advantages.
Date: December 31, 1997
Creator: King, D.L.; Boyson, W.E. & Hansen, B.R.
Partner: UNT Libraries Government Documents Department

OPTICALLY BASED CHARGE INJECTION SYSTEM FOR IONIZATION DETECTORS.

Description: An optically coupled charge injection system for ionization based radiation detectors which allows a test charge to be injected without the creation of ground loops has been developed. An ionization like signal from an external source is brought into the detector through an optical fiber and injected into the electrodes by means of a photodiode. As an application example, crosstalk measurements on a liquid Argon electromagnetic calorimeter readout electrodes were performed.
Date: September 11, 2001
Creator: CHEN,H.; CITTERIO,M.; LANNI,F.; LEITE,M.A.L.; RADEKA,V.; RESCIA,S. et al.
Partner: UNT Libraries Government Documents Department

Higher efficiency active quenching circuit for avalanche photodiodes

Description: An improved circuit for actively quenching and recharging avalanche photodiodes (APDs) which allows them to be biased to at least 30V above breakdown is presented. Using this circuit it is possible to achieve the high single photon detection efficiency inherent in Geiger mode APDs while maintaining a modest deadtime. The circuit is described and observed characteristics of the system are shown.
Date: June 1, 1993
Creator: Fenker, H.; Regan, T.; Thomas, J. & Wright, M.
Partner: UNT Libraries Government Documents Department

High density photovoltaic

Description: Photovoltaic technology can directly generate high voltages in a solid state material through the series interconnect of many photovoltaic diodes. We are investigating the feasibility of developing an electrically isolated, high-voltage power supply using miniature photovoltaic devices that convert optical energy to electrical energy.
Date: October 14, 1997
Creator: Haigh, R.E.; Jacobson, G.F. & Wojtczuk, S.
Partner: UNT Libraries Government Documents Department

Silicon-photodiode pyranometers: Operational characteristics, historical experiences, and new calibration procedures

Description: Small, low-cost, silicon-photodiode pyranometers are now widely used for solar irradiance measurements associated with solar thermal and photovoltaic power systems, as well as for agricultural applications. Without correction, the irradiance values indicated by these pyranometers may differ from the true broadband solar irradiance by over 10%. This paper identifies the time-of-day dependent factors responsible for these systematic errors, and describes new procedures that effectively compensate for the systematic influences. Application of the procedures should improve calibration methods and the accuracy of field measurements.
Date: November 1, 1997
Creator: King, D.L. & Myers, D.R.
Partner: UNT Libraries Government Documents Department