Sample records for radiation hard components

  1. Neutron radiation hardness of vacuum compatible two-component adhesives

    Microsoft Academic Search

    J. Bertsch; L. Goeltl; K. Kirch; B. Lauss; R. Zubler

    2009-01-01

    This paper reports the investigation of the irradiation dependent bonding strength of two-component glues which have low outgassing compatible with vacuum applications. The strength of the glue joints is compared before and after exposure to a thermal neutron fluence of 2.35×1016neutronspercm2. The goal of this work is to establish a glue which is applicable to join glass and metal parts

  2. Neutron radiation hardness of vacuum compatible two-component adhesives

    NASA Astrophysics Data System (ADS)

    Bertsch, J.; Goeltl, L.; Kirch, K.; Lauss, B.; Zubler, R.

    2009-04-01

    This paper reports the investigation of the irradiation dependent bonding strength of two-component glues which have low outgassing compatible with vacuum applications. The strength of the glue joints is compared before and after exposure to a thermal neutron fluence of 2.35×10 neutrons per cm. The goal of this work is to establish a glue which is applicable to join glass and metal parts of the ultra-cold neutron (UCN) guide system at the Paul Scherrer Institute's UCN source.

  3. Radiation hardness measurements on components of a full custom bipolar process

    NASA Astrophysics Data System (ADS)

    Barberis, P.; Benotto, F.; Cartiglia, N.; Dabrowski, W.; Dorfan, D. E.; Giubellino, P.; Pitzl, D.; Rowe, W. A.; Sadrozinski, H. F.-W.; Spencer, E. N.; Turala, M.; Wilder, M.

    1993-05-01

    We present the characterization of various components of the full custom bipolar process SHPi by Tektronix with respect to radiation hardness. The motivation of this work is to design a low-power, low-noise frontend with fast shaping for silicon microstrip detectors. We have tested BJTs ( npn of various size and a lateral pnp), JFETs, Schottky diodes, implanted resistors and NiChrome resistors. The devices were irradiated to 60Co dose of up to 5 Mrad in few steps, to fluence of 5.5?10 13n cm-2 of neutrons from a spallation source in few steps and to fluence of up to 1.1?10 14cm-2 of 650 MeV protons. It allows us to characterize the sensitivity of the devices on both ionization effects and displacement damage. We have measured the radiation effects on the dc parameters and characteristics of all components as well as on noise in npn BJTs of various size considered as candidates for the preamplifier input transistor. The most significant effect which we observe is the decrease of the current gain ? in bipolar transistors for low emitter current densities. Both important noise sources, i.e. the shot noise of the collector current and the thermal noise of the base spread resistance are unaffected by irradiation.

  4. A cloud chamber analysis of cosmic radiation at 3500 m. Part B: Results on the hard and soft components

    Microsoft Academic Search

    A. Lovati; A. Mura; C. Succi; G. Tagliaferri

    1954-01-01

    Summary  A multiplate cloud chamber has been operated at 3500 metres a.s.l., yielding 16000 photographs of random expansions. The present\\u000a paper is intended to investigate some questions pertaining to the general cosmic ray phenomenology. In particular, the zenith\\u000a angle dependence of the directional intensities of both hard and soft component is found to follow a squared cosine law. In\\u000a the range

  5. Evidence for a change in the radiation mechanism in the hard state of GRO J1655-40. Hysteresis in the broad-band noise components

    NASA Astrophysics Data System (ADS)

    Reig, P.; Papadakis, I. E.; Sobolewska, M. A.; Malzac, J.

    2013-11-01

    We have analysed archival data from the Rossi X-ray Timing Explorer (RXTE) to study the aperiodic variability of the black hole binary GRO J1655-40 during the hard state of the 2005 outburst. This work was motivated by the recent finding of a spectral change in the hard state X-ray radiation mechanism in black hole binaries. We computed the 0.008-64 Hz power spectral density during the rise and decay of the 2005 outburst, and we found that they were reasonably well modelled by the sum of two, broad Lorenztian functions in most cases (plus a narrow QPO), which correspond to three different variability components. Our aim is to study the evolution of the timing properties of the source during the outburst, by studying the correlation between the characteristics of the broad-band noise components in the power spectra and the source luminosity. Our results suggest that the whole power spectrum shifts to high (low) frequencies as the source luminosity increases (decreases), in agreement with previous studies of other black hole binaries. However, we also detect a strong `hysteresis' pattern in the `frequency-luminosity' plots, and show that the `critical' luminosity limit, above which the timing properties of the source change, is different during the rise and the decay phase of the outburst. We discuss the general implications of these results in the context of the truncated disc model.

  6. Development of radiation hard scintillators

    SciTech Connect

    Markley, F.; Woods, D.; Pla-Dalmau, A.; Foster, G. (Fermi National Accelerator Lab., Batavia, IL (United States)); Blackburn, R. (Michigan Univ., Nuclear Reactor Lab., Ann Arbor, MI (United States))

    1992-05-01

    Substantial improvements have been made in the radiation hardness of plastic scintillators. Cylinders of scintillating materials 2.2 cm in diameter and 1 cm thick have been exposed to 10 Mrads of gamma rays at a dose rate of 1 Mrad/h in a nitrogen atmosphere. One of the formulations tested showed an immediate decrease in pulse height of only 4% and has remained stable for 12 days while annealing in air. By comparison a commercial PVT scintillator showed an immediate decrease of 58% and after 43 days of annealing in air it improved to a 14% loss. The formulated sample consisted of 70 parts by weight of Dow polystyrene, 30 pbw of pentaphenyltrimethyltrisiloxane (Dow Corning DC 705 oil), 2 pbw of p-terphenyl, 0.2 pbw of tetraphenylbutadiene, and 0.5 pbw of UVASIL299LM from Ferro.

  7. Automated radiation hard ASIC design tool

    NASA Technical Reports Server (NTRS)

    White, Mike; Bartholet, Bill; Baze, Mark

    1993-01-01

    A commercial based, foundry independent, compiler design tool (ChipCrafter) with custom radiation hardened library cells is described. A unique analysis approach allows low hardness risk for Application Specific IC's (ASIC's). Accomplishments, radiation test results, and applications are described.

  8. Radiation-Hardness Data For Semiconductor Devices

    NASA Technical Reports Server (NTRS)

    Price, W. E.; Nichols, D. K.; Brown, S. F.; Gauthier, M. K.; Martin, K. E.

    1984-01-01

    Document presents data on and analysis of radiation hardness of various semiconductor devices. Data specifies total-dose radiation tolerance of devices. Volume 1 of report covers diodes, bipolar transistors, field effect transistors, silicon controlled rectifiers and optical devices. Volume 2 covers integrated circuits. Volume 3 provides detailed analysis of data in volumes 1 and 2.

  9. Radiation-hard static induction transistor

    SciTech Connect

    Hanes, M.H.; Bartko, J.; Hwang, J.M.; Rai-Choudhury, P.; Leslie, S.G.

    1988-12-01

    The static induction transistor (SIT) has been proposed as a preferred power switching device for applications in military and space environments because of its potential for radiation hardness, high-frequency operation, and the incorporation of on-chip smart power sensor and logic functions. Design, fabrication, and characteristics of a 350 V, 100 A buried gate SIT are described. The potential radiation hardness of this class of devices was evaluated by measurement of SIT characteristics after irradiation with 100 Mrad electrons (2 MeV), and up to 10%16% fission neutrons/cm/sup 2/. High-temperature operation and the possibility of radiation damage self-annealing are discussed.

  10. Review of radiation hard electronics activities at European Space Agency

    NASA Astrophysics Data System (ADS)

    Furano, G.; Jansen, R.; Menicucci, A.

    2013-02-01

    Several Research and Development activities are ongoing at European Space Agency [1] to secure the supply of key electronic parts for current and future space avionics systems. Analogously to astro-particle and high-energy physics, the space missions radiation environment drives the radiation hardness requirements, which limits availability of suitable electronic components. In particular for the future ESA flagship Jupiter science mission, the necessary processing, reliability, mass, power performance requirements are difficult to meet with current components and systems with sufficient radiation tolerance margins. Improved radiation characterisation and modelling of the Jupiter radiation environment as well as operational radiation monitoring during the mission will be key in ensuring adequate margins for the operation of electronic components.

  11. Radiation Hardness Assurance for Space Systems

    NASA Technical Reports Server (NTRS)

    Poivey, Christian; Day, John H. (Technical Monitor)

    2002-01-01

    The space radiation environment can lead to extremely harsh operating conditions for on-board electronic box and systems. The characteristics of the radiation environment are highly dependent on the type of mission (date, duration and orbit). Radiation accelerates the aging of the electronic parts and material and can lead to a degradation of electrical performance; it can also create transient phenomena on parts. Such damage at the part level can induce damage or functional failure at electronic box, subsystem, and system levels. A rigorous methodology is needed to ensure that the radiation environment does not compromise the functionality and performance of the electronics during the system life. This methodology is called hardness assurance. It consists of those activities undertaken to ensure that the electronic piece parts placed in the space system perform to their design specifications after exposure to the space environment. It deals with system requirements, environmental definitions, part selection, part testing, shielding and radiation tolerant design. All these elements should play together in order to produce a system tolerant to.the radiation environment. An overview of the different steps of a space system hardness assurance program is given in section 2. In order to define the mission radiation specifications and compare these requirements to radiation test data, a detailed knowledge of the space environment and the corresponding electronic device failure mechanisms is required. The presentation by J. Mazur deals with the Earth space radiation environment as well as the internal environment of a spacecraft. The presentation by J. Schwank deals with ionization effects, and the presentation by T. Weatherford deals with Single particle Event Phenomena (SEP) in semiconductor devices and microcircuits. These three presentations provide more detailed background to complement the sections 3 and 4. Part selection and categorization are discussed in section 5. Section 6 presents the organization of the hardness assurance within a project. Section 7 discusses emerging radiation hardness assurance issues.

  12. Radiation hardness assurances categories for COTS technologies

    SciTech Connect

    Hash, G.L.; Shaneyfelt, M.R.; Sexton, F.W.; Winokur, P.S.

    1997-03-01

    A comparison of the radiation tolerance of three commercial, and one radiation hardened SRAM is presented for four radiation environments. This work has shown the difficulty associated with strictly categorizing a device based solely on its radiation response, since its category depends on the specific radiation environment considered. For example, the 3.3-V Paradigm SRAM could be considered a radiation-tolerant device except for its SEU response. A more useful classification depends on the methods the manufacturer uses to ensure radiation hardness, i.e. whether specific design and process techniques have been used to harden the device. Finally, this work has shown that burned-in devices may fail functionally as much as 50% lower in total dose environments than non-burned-in devices. No burn-in effect was seen in dose-rate upset, latchup, or SEE environments. The user must ensure that total dose lot acceptance testing was performed on burned-in devices.

  13. Characterization of Radiation Hard Silicon Materials

    SciTech Connect

    Luukka, P.; Li, Z.; J. Harkonen, E. Tuovinen, S. Czellar, V. Eremin, E. Tuominen, E. Verbitskaya

    2009-02-24

    Segmented silicon detectors are widely used in modern high-energy physics (HEP) experiments due to their excellent spatial resolution and well-established manufacturing technology. However, in such experiments the detectors are exposed to high fluences of particle radiation, which causes irreversible crystallographic defects in the silicon material. Since 1990's, considerable amount of research has gone into improving the radiation hardness of silicon detectors. One very promising approach is to use magnetic Czochralski silicon (MCz-Si) that has been found to be more radiation hard against charged hadrons than traditional Float Zone silicon material (Fz-Si) used in the current HEP applications. Other approaches include operating the devices at cryogenic temperatures and designing special detector structures such as p-type detectors or semi-3D detectors. In order to demonstrate that the developed technologies are suitable for the HEP experiments, it is necessary to extensively characterize the potentially radiation hard detectors. We have an excellent instrument for this, the Cryogenic Transient Current Technique (C-TCT) measurement setup, which is an effective research tool for studying heavily irradiated silicon detectors. With the C-TCT setup it is possible to extract the full depletion voltage, effective trapping time, electric field distribution and the sign of the space charge in the silicon bulk in the temperature range of 45-300 K. This articles presents a description of this setup and measurement results from detectors processed of MCz-Si.

  14. Radiation-hard/high-speed data transmission using optical links

    NASA Astrophysics Data System (ADS)

    Gan, K. K.; Abi, B.; Fernando, W.; Kagan, H. P.; Kass, R. D.; Lebbai, M. R. M.; Moore, J. R.; Rizatdinova, F.; Skubic, P. L.; Smith, D. S.

    2009-12-01

    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 investigate the radiation-hardness of various components for possible application in the data transmission upgrade. We study the radiation-hardness of VCSELs (Vertical-Cavity Surface-Emitting Laser) and GaAs and silicon PINs from various sources using 24 GeV/c protons at CERN. 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, especially for the GaAs devices. We have designed the ASICs for the opto-link applications and find that the degradation with radiation is acceptable.

  15. February 24, 2009 Radiation-Hardness of VCSEL/PIN

    E-print Network

    Gan, K. K.

    February 24, 2009 Radiation-Hardness of VCSEL/PIN W. Fernando, K.K. Gan, H.P. Kagan, R.D. Kass, J Introduction Radiation hardness of PINs Radiation hardness of VCSELs Summary #12;K.K. Gan ATLAS Upgrade with 50% safety factor #12;K.K. Gan ATLAS Upgrade Week 5 K.K. Gan 5 Radiation-Hardness of Silicon PIN

  16. GLUON RADIATION PATTERNS IN HARD SCATTERING EVENTS

    E-print Network

    Dieter Zeppenfeld

    1995-03-14

    The radiation pattern of relatively soft gluons in hard scattering events is sensitive to the underlying color structure. As an example I consider heavy Higgs production via weak boson fusion at the LHC. A minijet veto, which makes use of the different patterns for signal and backgrounds, provides an effective Higgs search tool. Talk presented at the Conference on Physics {\\it Beyond the Standard Model IV}, Lake Tahoe, California, December 14--18, 1994.

  17. MICROMEGAS: High rate and radiation hardness results

    SciTech Connect

    Puill, G.; Derre, J.; Giomataris, Y.; Rebourgeard, P.

    1999-12-01

    In this report, the authors present results of gain studies using various gas mixtures in a novel structure of gaseous detector called MICROMEGAS which is under development at Saclay. The authors in particular studied the maximum of gain achievable with MICROMEGAS before the discharge. They tried various gas mixtures (Argon, Neon, CF{sub 4}) with various proportions of quencher (Isobutane, Cyclohexane, DME). They also studied the radiation hardness of MICROMEGAS using Argon-Isobutane and CF{sub 4}-Isobutane mixtures.

  18. Radiation Hardness Assurance (RHA) for Space Systems

    NASA Technical Reports Server (NTRS)

    Poivey, Christian; Buchner, Stephen

    2007-01-01

    This presentation discusses radiation hardness assurance (RHA) for space systems, providing both the programmatic aspects of RHA and the RHA procedure. RHA consists of all activities undertaken to ensure that the electronics and materials of a space system perform to their design specifications after exposure to the space radiation environment. RHA also pertains to environment definition, part selection, part testing, spacecraft layout, radiation tolerant design, and mission/system/subsystems requirements. RHA procedure consists of establishing mission requirements, defining and evaluating the radiation hazard, selecting and categorizing the appropriate parts, and evaluating circuit response to hazard. The RHA approach is based on risk management and is confined only to parts, it includes spacecraft layout, system/subsystem/circuit design, and system requirements and system operations. RHA should be taken into account in the early phases of a program including the proposal and feasibility analysis phases.

  19. New component of hard X-rays in solar flares

    Microsoft Academic Search

    R. P. Lin; R. A. Schwartz; R. M. Pelling; K. C. Hurley

    1981-01-01

    We present high resolution (approx.1 keV FWHM) spectral measurements from 13 to 300 keV of a solar flare hard X-ray burst observed on 1980 June 27 by a balloon-borne array of cooled germanium planar detectors. At energies below approx.35 keV we identify a new component of solar flare hard X-rays. This component is characterized by an extremely steep spectrum which

  20. Flux monitor diode radiation hardness testing

    NASA Astrophysics Data System (ADS)

    Lombardi, M. L.; Favalli, A.; Goda, J. M.; Ianakiev, K. D.; Moss, C. E.

    2011-10-01

    A flux monitor diode is being explored as an option for measurement of the output of an X-ray tube that is used for active transmission measurements on a pipe containing UF 6 gas. The measured flux can be used to correct for any instabilities in the X-ray tube or the high voltage power supply. For this measurement, we are using a silicon junction p-n photodiode, model AXUV100GX, developed by International Radiation Detectors, Inc. (IRD, Inc.). This diode has a silicon thickness of 104 ? and a thin (3-7 nm) silicon dioxide junction passivating, protective entrance window. These diodes have been extensively tested for radiation hardness in the UV range. However, we intend to operate mainly in the 10-40 keV X-ray region. We are performing radiation hardness testing over this energy range, with the energy spectrum that would pass through the diode during normal operation. A long-term measurement was performed at a high flux, which simulated over 80 years of operation. No significant degradation was seen over this time. Fluctuations were found to be within the 0.1% operationally acceptable error range. After irradiation, an I- V characterization showed a temporary irradiation effect which decayed over time. This effect is small because we operate the diode without external bias.

  1. Radiation effects on eye components

    NASA Astrophysics Data System (ADS)

    Durchschlag, H.; Fochler, C.; Abraham, K.; Kulawik, B.

    1999-08-01

    The most important water-soluble components of the vertebrate eye (lens proteins, aqueous humor, vitreous, hyaluronic acid, ascorbic acid) have been investigated in aqueous solution, after preceding X- or UV-irradiation. Spectroscopic, chromatographic, electrophoretic, hydrodynamic and analytic techniques have been applied, to monitor several radiation damages such as destruction of aromatic and sulfur-containing amino acids, aggregation, crosslinking, dissociation, fragmentation, and partial unfolding. Various substances were found which were able to protect eye components effectively against radiation, some of them being also of medical relevance.

  2. Radiation-Hard Optical Link for SLHC

    E-print Network

    K. K. Gan

    2008-12-29

    We study the feasibility of fabricating an optical link for the SLHC ATLAS silicon tracker based on the current pixel optical link architecture. The electrical signals between the current pixel modules and the optical modules are transmitted via micro-twisted cables. The optical signals between the optical modules and the data acquisition system are transmitted via radiation-hard/low-bandwidth SIMM fibres fusion spliced to radiation-tolerant/medium-bandwidth GRIN fibres. The link has several nice features. We have measured the bandwidths of the micro twisted-pair cables to be ~ 1 Gb/s and the fusion spliced fibre ribbon to be ~ 2 Gb/s. We have irradiated PIN and VCSEL arrays with 24 GeV protons and find the arrays can operate up to the SLHC dosage. We have also demonstrated the feasibility of fabricating a novel opto-pack for housing VCSEL and PIN arrays with BeO as the substrate.

  3. Radiation Hard AlGaN Detectors and Imager

    SciTech Connect

    None

    2012-05-01

    Radiation hardness of AlGaN photodiodes was tested using a 65 MeV proton beam with a total proton fluence of 3x10{sup 12} protons/cm{sup 2}. AlGaN Deep UV Photodiode have extremely high radiation hardness. These new devices have mission critical applications in high energy density physics (HEDP) and space explorations. These new devices satisfy radiation hardness requirements by NIF. NSTec is developing next generation AlGaN optoelectronics and imagers.

  4. Fault-Tolerant, Radiation-Hard DSP

    NASA Technical Reports Server (NTRS)

    Czajkowski, David

    2011-01-01

    Commercial digital signal processors (DSPs) for use in high-speed satellite computers are challenged by the damaging effects of space radiation, mainly single event upsets (SEUs) and single event functional interrupts (SEFIs). Innovations have been developed for mitigating the effects of SEUs and SEFIs, enabling the use of very-highspeed commercial DSPs with improved SEU tolerances. Time-triple modular redundancy (TTMR) is a method of applying traditional triple modular redundancy on a single processor, exploiting the VLIW (very long instruction word) class of parallel processors. TTMR improves SEU rates substantially. SEFIs are solved by a SEFI-hardened core circuit, external to the microprocessor. It monitors the health of the processor, and if a SEFI occurs, forces the processor to return to performance through a series of escalating events. TTMR and hardened-core solutions were developed for both DSPs and reconfigurable field-programmable gate arrays (FPGAs). This includes advancement of TTMR algorithms for DSPs and reconfigurable FPGAs, plus a rad-hard, hardened-core integrated circuit that services both the DSP and FPGA. Additionally, a combined DSP and FPGA board architecture was fully developed into a rad-hard engineering product. This technology enables use of commercial off-the-shelf (COTS) DSPs in computers for satellite and other space applications, allowing rapid deployment at a much lower cost. Traditional rad-hard space computers are very expensive and typically have long lead times. These computers are either based on traditional rad-hard processors, which have extremely low computational performance, or triple modular redundant (TMR) FPGA arrays, which suffer from power and complexity issues. Even more frustrating is that the TMR arrays of FPGAs require a fixed, external rad-hard voting element, thereby causing them to lose much of their reconfiguration capability and in some cases significant speed reduction. The benefits of COTS high-performance signal processing include significant increase in onboard science data processing, enabling orders of magnitude reduction in required communication bandwidth for science data return, orders of magnitude improvement in onboard mission planning and critical decision making, and the ability to rapidly respond to changing mission environments, thus enabling opportunistic science and orders of magnitude reduction in the cost of mission operations through reduction of required staff. Additional benefits of COTS-based, high-performance signal processing include the ability to leverage considerable commercial and academic investments in advanced computing tools, techniques, and infra structure, and the familiarity of the science and IT community with these computing environments.

  5. Component mixers and a hardness result for counterfeiting quantum money

    E-print Network

    Andrew Lutomirski

    2011-07-01

    In this paper we give the first proof that, under reasonable assumptions, a problem related to counterfeiting quantum money from knots [Farhi et al. 2010] is hard. Along the way, we introduce the concept of a component mixer, define three new classical query problems and associated complexity classes related to graph isomorphism and group membership, and conjecture an oracle separating QCMA from QMA.

  6. High efficiency, radiation-hard solar cells

    SciTech Connect

    Ager III, J.W.; Walukiewicz, W.

    2004-10-22

    The direct gap of the In{sub 1-x}Ga{sub x}N alloy system extends continuously from InN (0.7 eV, in the near IR) to GaN (3.4 eV, in the mid-ultraviolet). This opens the intriguing possibility of using this single ternary alloy system in single or multi-junction (MJ) solar cells of the type used for space-based surveillance satellites. To evaluate the suitability of In{sub 1-x}Ga{sub x}N as a material for space applications, high quality thin films were grown with molecular beam epitaxy and extensive damage testing with electron, proton, and alpha particle radiation was performed. Using the room temperature photoluminescence intensity as a indirect measure of minority carrier lifetime, it is shown that In{sub 1-x}Ga{sub x}N retains its optoelectronic properties at radiation damage doses at least 2 orders of magnitude higher than the damage thresholds of the materials (GaAs and GaInP) currently used in high efficiency MJ cells. This indicates that the In{sub 1-x}Ga{sub x}N is well-suited for the future development of ultra radiation-hard optoelectronics. Critical issues affecting development of solar cells using this material system were addressed. The presence of an electron-rich surface layer in InN and In{sub 1-x}Ga{sub x}N (0 < x < 0.63) was investigated; it was shown that this is a less significant effect at large x. Evidence of p-type activity below the surface in Mg-doped InN was obtained; this is a significant step toward achieving photovoltaic action and, ultimately, a solar cell using this material.

  7. Development of a radiation-hard photomultiplier tube

    NASA Technical Reports Server (NTRS)

    Birnbaum, M. M.; Bunker, R. L.; Roderick, J.; Stephenson, K.

    1984-01-01

    In a radiation-hard photomultiplier tube (PMT) such as has been developed for stabilization of the Galileo spacecraft as it goes through the Jovian high energy radiation belts, the primary effects of high energy electron and proton radiation that must be resisted are the production of fluorescence and Cerenkov emission. The present PMT envelope is ceramic rather than glass, and employs a special, electron-focusing design which will collect, accelerate and amplify electrons only from desired photocathode areas. Tests in a Co-60 radiation facility have shown that the radiation-hard PMT produces less than 2.5 percent of the radiation noise of a standard PMT.

  8. Test bench development for the radiation Hard GBTX ASIC

    NASA Astrophysics Data System (ADS)

    Leitao, P.; Feger, S.; Porret, D.; Baron, S.; Wyllie, K.; Barros Marin, M.; Figueiredo, D.; Francisco, R.; Da Silva, J. C.; Grassi, T.; Moreira, P.

    2015-01-01

    This paper presents the development of the GBTX radiation hard ASIC test bench. Developed for the LHC accelerator upgrade programs, the GBTX implements a bidirectional 4.8 Gb/s link between the radiation hard on-detector custom electronics and the off-detector systems. The test bench was used for functional testing of the GBTX and to evaluate its performance in a radiation environment, by conducting Total Ionizing Dose and Single-Event Upsets tests campaigns.

  9. Measuring the radiation field and radiation hard detectors at JET: Recent developments

    NASA Astrophysics Data System (ADS)

    Murari, A.; Edlington, T.; Angelone, M.; Bertalot, L.; Bolshakova, I.; Bonheure, G.; Brzozowski, J.; Coccorese, V.; Holyaka, R.; Kiptily, V.; Lengar, I.; Morgan, P.; Pillon, M.; Popovichev, S.; Prior, P.; Prokopowicz, R.; Quercia, A.; Rubel, M.; Santala, M.; Shevelev, A.; Syme, B.; Vagliasindi, G.; Villari, R.; Zoita, V. L.; JET-EFDA Contributors

    2008-08-01

    Since in ITER the radiation field will be much more demanding than that of present day devices, research programmes at JET are aimed at developing radiation hard diagnostics and related components. Initially, significant efforts are devoted to determining the radiation field of both the plasma and in the immediate environment with better accuracy. New developments in MCNP calculations and dedicated measurements provide useful information about the radiation field in the Torus Hall, even during non-operational periods. The effect of using Beryllium in the near future for JET first wall, is being assessed. New materials for activation samples are under consideration and will be tested to improve the calibration accuracy of JET neutron diagnostics. The long-term goal of this work is to obtain spectrometric information from an appropriate combination of different materials. Several studies are under way to modify the radiation field at the detectors by using LiH or pure water as neutron filters, to alleviate the problem of the background in ?-ray measurements. A suite of radiation hard detectors for neutrons, magnetic field and charged particles are being developed. Super-heated fluid neutron detectors, used for yield and imaging, are being upgraded, in order to provide a broad-band spectrometric capability. Chemical vapour deposited diamond diodes are being qualified as counters and as spectrometers. Prototypes of Hall probes made of InSb have been installed on the machine and have provided some preliminary results. Si-on-insulator detectors are under development for use in neutral particle analysers and are currently being bench-tested. Some attention is being devoted to optical components, fibres and mirrors, and to investigating radiation hard electronics using reconfigurable Field Programmable Gate Arrays.

  10. Radiation hard diamond sensors for future tracking applications

    Microsoft Academic Search

    W. Adam; W. de Boer; E. Borchi; M. Bruzzi; C. Colledani; P. D’Angelo; V. Dabrowski; W. Dulinski; B. van Eijk; V. Eremin; F. Fizzotti; H. Frais-Kölbl; C. Furetta; K. K. Gan; A. Gorisek; E. Griesmayer; E. Grigoriev; F. Hartjes; J. Hrubec; F. Huegging; H. Kagan; J. Kaplon; R. Kass; K. T. Knöpfle; M. Krammer; W. Lange; A. Logiudice; C. Manfredotti; M. Mathes; D. Menichelli; M. Mishina; L. Moroni; J. Noomen; A. Oh; H. Pernegger; M. Pernicka; R. Potenza; J. L. Riester; A. Rudge; S. Sala; S. Schnetzer; S. Sciortino; R. Stone; C. Sutera; W. Trischuk; J. J. Velthuis; B. Vincenzo; P. Weilhammer; J. Weingarten; N. Wermes; W. Zeuner

    2006-01-01

    Progress in experimental particle physics in the coming decade depends crucially upon the ability to carry out experiments in high-radiation areas. In order to perform these complex and expensive experiments, new radiation hard technologies must be developed. This paper discusses the use of diamond detectors in future tracking applications and their survivability in the highest radiation environments. We present results

  11. Method for producing hard-surfaced tools and machine components

    DOEpatents

    McHargue, Carl J. (Farragut, TN)

    1985-01-01

    In one aspect, the invention comprises a method for producing tools and machine components having superhard crystalline-ceramic work surfaces. Broadly, the method comprises two steps: A tool or machine component having a ceramic near-surface region is mounted in ion-implantation apparatus. The region then is implanted with metal ions to form, in the region, a metastable alloy of the ions and said ceramic. The region containing the alloy is characterized by a significant increase in hardness properties, such as microhardness, fracture-toughness, and/or scratch-resistance. The resulting improved article has good thermal stability at temperatures characteristic of typical tool and machine-component uses. The method is relatively simple and reproducible.

  12. Method for producing hard-surfaced tools and machine components

    DOEpatents

    McHargue, C.J.

    1981-10-21

    In one aspect, the invention comprises a method for producing tools and machine components having superhard crystalline-ceramic work surfaces. Broadly, the method comprises two steps: a tool or machine component having a ceramic near-surface region is mounted in ion-implantation apparatus. The region then is implanted with metal ions to form, in the region, a metastable alloy of the ions and said ceramic. The region containing the alloy is characterized by a significant increase in hardness properties, such as microhardness, fracture-toughness, and/or scratch-resistance. The resulting improved article has good thermal stability at temperatures characteristic of typical tool and machine-component uses. The method is relatively simple and reproducible.

  13. Sustainably Sourced, Thermally Resistant, Radiation Hard Biopolymer

    NASA Technical Reports Server (NTRS)

    Pugel, Diane

    2011-01-01

    This material represents a breakthrough in the production, manufacturing, and application of thermal protection system (TPS) materials and radiation shielding, as this represents the first effort to develop a non-metallic, non-ceramic, biomaterial-based, sustainable TPS with the capability to also act as radiation shielding. Until now, the standing philosophy for radiation shielding involved carrying the shielding at liftoff or utilizing onboard water sources. This shielding material could be grown onboard and applied as needed prior to different radiation landscapes (commonly seen during missions involving gravitational assists). The material is a bioplastic material. Bioplastics are any combination of a biopolymer and a plasticizer. In this case, the biopolymer is a starch-based material and a commonly accessible plasticizer. Starch molecules are composed of two major polymers: amylase and amylopectin. The biopolymer phenolic compounds are common to the ablative thermal protection system family of materials. With similar constituents come similar chemical ablation processes, with the potential to have comparable, if not better, ablation characteristics. It can also be used as a flame-resistant barrier for commercial applications in buildings, homes, cars, and heater firewall material. The biopolymer is observed to undergo chemical transformations (oxidative and structural degradation) at radiation doses that are 1,000 times the maximum dose of an unmanned mission (10-25 Mrad), indicating that it would be a viable candidate for robust radiation shielding. As a comparison, the total integrated radiation dose for a three-year manned mission to Mars is 0.1 krad, far below the radiation limit at which starch molecules degrade. For electron radiation, the biopolymer starches show minimal deterioration when exposed to energies greater than 180 keV. This flame-resistant, thermal-insulating material is non-hazardous and may be sustainably sourced. It poses no hazardous waste threats during its lifecycle. The material composition is radiation-tolerant up to megarad doses, indicating its use as a radiation shielding material. It is lightweight, non-metallic, and able to be mechanically densified, permitting a tunable gradient of thermal and radiation protection as needed. The dual-use (thermal and radiation shielding), sustainable nature of this material makes it suitable for both industrial applications as a sustainable/green building material, and for space applications as thermal protection material and radiation shield.

  14. A study on the radiation hardness of lead tungstate crystals

    Microsoft Academic Search

    R. Y. Zhu; Q. Deng; H. Newman; C. L. Woody; J. A. Kierstead; S. P. Stoll

    1998-01-01

    This report presents recent progress of a study on the radiation damage in lead tungstate (PbWO4) crystals. The dose rate dependence of radiation damage in PbWO4 has been observed. An optimization of the oxygen compensation through post-growth thermal annealing has led to PbWO4 samples with significantly improved radiation hardness. Front irradiation is found to cause a factor of 2 to

  15. Emerging radiation hardness assurance (RHA) issues: a NASA approach for space flight programs

    Microsoft Academic Search

    Kenneth A. LaBel; Allan H. Johnston; Janet L. Barth; Robert A. Reed; Charles E. Barnes

    1998-01-01

    Spacecraft performance requirements drive the utilization of commercial-off-the-shelf (COTS) components and emerging technologies in systems. The response of these technologies to radiation is often complex. This engenders a set of emerging radiation hardness assurance (RHA) issues which include displacement damage in optocouplers, high-precision and hybrid devices, enhanced low dose rate (ELDR) and proton damage enhancement (PDE) in linear circuits, linear

  16. Electromagnetic Radiation Hardness of Diamond Detectors

    E-print Network

    T. Behnke; M. Doucet; N. Ghodbane; A. Imhof; C. Martinez; W. Zeuner

    2001-08-22

    The behavior of artificially grown CVD diamond films under intense electromagnetic radiation has been studied. The properties of irradiated diamond samples have been investigated using the method of thermally stimulated current and by studying their charge collection properties. Diamonds have been found to remain unaffected after doses of 6.8 MGy of 10 keV photons and 10 MGy of MeV-range photons. This observation makes diamond an attractive detector material for a calorimeter in the very forward region of the proposed TESLA detector.

  17. Novel radiation hard microfabricated scintillation detectors with high spatial resolution

    E-print Network

    Dalang, Robert C.

    Novel radiation hard microfabricated scintillation detectors with high spatial resolution A, Switzerland a r t i c l e i n f o Available online 4 July 2009 Keywords: Scintillation detectors Microfabrication Microfluidics a b s t r a c t A novel liquid scintillation detector with high spatial resolution

  18. Curve Fitting Solar Cell Degradation Due to Hard Particle Radiation

    NASA Technical Reports Server (NTRS)

    Gaddy, Edward M.; Cikoski, Rebecca; Mekadenaumporn, Danchai

    2003-01-01

    This paper investigates the suitability of the equation for accurately defining solar cell parameter degradation as a function of hard particle radiation. The paper also provides methods for determining the constants in the equation and compares results from this equation to those obtained by the more traditionally used.

  19. Scintillation Detectors for Radiation-Hard Electromagnetic Calorimeters

    Microsoft Academic Search

    H. Löhner

    2005-01-01

    For the application in the compact and radiation hard electromagnetic (EM) calorimeter in the PANDA detection system at the new GSI facility, we have started to advance scintillation crystals and the light detection technique. PANDA is the universal internal-target detection system for charmonium spectroscopy and the search for glue-balls and hybrid states in antiproton annihilations. In particular, the large dynamic

  20. Study of runaway electrons using dosimetry of hard x-ray radiations in Damavand tokamak

    SciTech Connect

    Rasouli, C.; Pourshahab, B.; Rasouli, H. [Plasma Physics and Nuclear Fusion Research School, Nuclear Science and Technology Research Institute, AEOI, PO Box 14155-1339, Tehran (Iran, Islamic Republic of)] [Plasma Physics and Nuclear Fusion Research School, Nuclear Science and Technology Research Institute, AEOI, PO Box 14155-1339, Tehran (Iran, Islamic Republic of); Hosseini Pooya, S. M.; Orouji, T. [Radiation Application Research School, Nuclear Science and Technology Research Institute, AEOI, PO Box 14155-1339, Tehran (Iran, Islamic Republic of)] [Radiation Application Research School, Nuclear Science and Technology Research Institute, AEOI, PO Box 14155-1339, Tehran (Iran, Islamic Republic of)

    2014-05-15

    In this work several studies have been conducted on hard x-ray emissions of Damavand tokamak based on radiation dosimetry using the Thermoluminescence method. The goal was to understand interactions of runaway electrons with plasma particles, vessel wall, and plasma facing components. Total of 354 GR-200 (LiF:Mg,Cu,P) thermoluminescence dosimeter (TLD) crystals have been placed on 118 points – three TLDs per point – to map hard x-ray radiation doses on the exterior of the vacuum vessel. Results show two distinctive levels of x-ray radiations doses on the exterior of the vessel. The low-dose area on which measured dose is about 0.5 mSv/shot. In the low-dose area there is no particular component inside the vessel. On the contrary, on high-dose area of the vessel, x-ray radiations dose exceeds 30 mSv/shot. The high-dose area coincides with the position of limiters, magnetic probe ducts, and vacuum vessel intersections. Among the high-dose areas, the highest level of dose is measured in the position of the limiter, which could be due to its direct contact with the plasma column and with runaway electrons. Direct collisions of runaway electrons with the vessel wall and plasma facing components make a major contribution for production of hard x-ray photons in Damavand tokamak.

  1. Hard X-Ray Radiation in the Coma Cluster Spectrum

    NASA Astrophysics Data System (ADS)

    Fusco-Femiano, Roberto; Dal Fiume, Daniele; Feretti, Luigina; Giovannini, Gabriele; Grandi, Paola; Matt, Giorgio; Molendi, Silvano; Santangelo, Andrea

    1999-03-01

    Hard X-ray radiation has been detected for the first time in the Coma Cluster by BeppoSAX. Thanks to the unprecedented sensitivity of the Phoswich Detection System (PDS) instrument, the source has been detected up to ~80 keV. There is clear evidence (4.5 ?) for nonthermal emission in excess of thermal emission above ~25 keV. The hard excess is very unlikely to be the result of X Comae, the Seyfert 1 galaxy that is present in the field of view of the PDS. A hard spectral tail that is due to inverse Compton scattering on cosmic microwave background photons is predicted in clusters, like Coma, with radio halos. Combining the present results with radio observations, a volume-averaged intracluster magnetic field of ~0.15 ?G is derived, while the electron energy density of the emitting electrons is ~7×10-14 ergs cm-3.

  2. Radiation hardness of polysulphone and polycarbonate elements for LHC detectors

    E-print Network

    Hauviller, Claude; Bychkov, V; Golikov, V V; Kekelidze, G D; Lobastov, S P; Luschikov, V I; Peshekhonov, V D

    1998-01-01

    In the TRT Inner Detector being developed for ATLAS, elements made from plastic materials are widely used. In order to meet necessary requirements of the construction, these materials should have a high radiation hardness. This work presents a study of mechanical features of polysulphone and polycarbonate in dependence on the radiation dose. The results of measurements have shown a weak dependence of mechanical properties of polysulphone and polycarbonate on the absorbed dose up to the value of 1 MGy. So, the products from these materials could be used to construct detectors at LHC, at least on the mechanical point of view.

  3. Development of a radiation-hard CMOS process

    NASA Technical Reports Server (NTRS)

    Power, W. L.

    1983-01-01

    It is recommended that various techniques be investigated which appear to have the potential for improving the radiation hardness of CMOS devices for prolonged space flight mission. The three key recommended processing techniques are: (1) making the gate oxide thin. It has been shown that radiation degradation is proportional to the cube of oxide thickness so that a relatively small reduction in thickness can greatly improve radiation resistance; (2) cleanliness and contamination control; and (3) to investigate different oxide growth (low temperature dry, TCE and HCL). All three produce high quality clean oxides, which are more radiation tolerant. Technique 2 addresses the reduction of metallic contamination. Technique 3 will produce a higher quality oxide by using slow growth rate conditions, and will minimize the effects of any residual sodium contamination through the introduction of hydrogen and chlorine into the oxide during growth.

  4. Scintillation Detectors for Radiation-Hard Electromagnetic Calorimeters

    NASA Astrophysics Data System (ADS)

    Löhner, H.

    2005-02-01

    For the application in the compact and radiation hard electromagnetic (EM) calorimeter in the PANDA detection system at the new GSI facility, we have started to advance scintillation crystals and the light detection technique. PANDA is the universal internal-target detection system for charmonium spectroscopy and the search for glue-balls and hybrid states in antiproton annihilations. In particular, the large dynamic range from several GeV down to a detection threshold of some MeV for EM radiation and the expected high background rate of neutrons and ions will impose severe requirements on crystals and light sensors. In the magnetic environment of tracking devices the use of Avalanche Photodiodes (APD's) is preferred. In order to achieve suitable resolution for low energy hadrons and photons, the light output of crystals will have to be improved by special production techniques, activation and doping. These procedures might have implications for the radiation hardness. We report on measurements of signal response and radiation damage in crystals of PbWO4 and BGO both from the BTCP (Russia) and SICCAS (China) production sites. Beams of protons, electrons and photons have been applied while detectors with either phototube or APD readout were operated in the range from room temperature to -20°C. Results on light yield and energy resolution are presented. We report on the reduction of light transmission after proton irradiation and results from electron-spin resonance studies on irradiated crystals to analyse the cause of radiation damage.

  5. Impact of Radiation Hardness and Operating Temperatures of Silicon Carbide Electronics on Space Power System Mass

    NASA Technical Reports Server (NTRS)

    Juhasz, Albert J.; Tew, Roy C.; Schwarze, Gene E.

    1998-01-01

    The effect of silicon carbide (SiC) electronics operating temperatures on Power Management and Distribution (PMAD), or Power Conditioning (PC), subsystem radiator size and mass requirements was evaluated for three power output levels (100 kW(e) , 1 MW(e), and 10 MW(e)) for near term technology ( i.e. 1500 K turbine inlet temperature) Closed Cycle Gas Turbine (CCGT) power systems with a High Temperature Gas Reactor (HTGR) heat source. The study was conducted for assumed PC radiator temperatures ranging from 370 to 845 K and for three scenarios of electrical energy to heat conversion levels which needed to be rejected to space by means of the PC radiator. In addition, during part of the study the radiation hardness of the PC electronics was varied at a fixed separation distance to estimate its effect on the mass of the instrument rated reactor shadow shield. With both the PC radiator and the conical shadow shield representing major components of the overall power system the influence of the above on total power system mass was also determined. As expected, results show that the greatest actual mass savings achieved by the use of SiC electronics occur with high capacity power systems. Moreover, raising the PC radiator temperature above 600 K yields only small additional system mass savings. The effect of increased radiation hardness on total system mass is to reduce system mass by virtue of lowering the shield mass.

  6. Radiation-hard electrical coil and method for its fabrication

    DOEpatents

    Grieggs, R.J.; Blake, R.D.; Gac, F.D.

    1982-06-29

    A radiation-hard insulated electrical coil and method for making the same are disclosed. In accordance with the method, a conductor, preferably copper, is wrapped with an aluminum strip and then tightly wound into a coil. The aluminum-wrapped coil is then annealed to relax the conductor in the coiled configuration. The annealed coil is then immersed in an alkaline solution to dissolve the aluminum strip, leaving the bare conductor in a coiled configuration with all of the windings closely packed yet uniformly spaced from one another. The coil is then insulated with a refractory insulating material. In the preferred embodiment, the coil is insulated by coating it with a vitreous enamel and subsequently potting the enamelled coil in a castable ceramic concrete. The resulting coil is substantially insensitive to radiation and may be operated continuously in high radiation environments for long periods of time.

  7. Hard X-ray Radiation in the Coma Cluster

    NASA Astrophysics Data System (ADS)

    Fusco-Femiano, R.; dal Fiume, D.; Feretti, L.; Giovannini, G.; Matt, G.; Molendi, S.

    1998-12-01

    Hard X-ray radiation has been detected for the first time in the Coma cluster spectrum, during the AO-1 observations. Thanks to the unprecedented sensitivity of the Phoswich Detection System (PDS) onboard the Beppo-SAX observatory, the source has been detected up to ~80 keV. There is clear evidence for non-thermal emission in excess to the thermal one above ~25 keV at a 4.5 sigma level. Our analysis is able to exclude that the hard excess may be due to X Comae, a type I Seyfert galaxy present in the FOV of the PDS. A volume-averaged intracluster magnetic field of 0.16 mu G is derived, in order to account for the observed syncrotron radio emission. This value is in contrast with the estimates based on Faraday rotation measurements seen through the hot intracluster medium of the Coma Cluster.

  8. Radiation heating in selected NERVA engine components

    NASA Technical Reports Server (NTRS)

    Courtney, J. C.; Hertelendy, N. A.; Lindsey, B. A.

    1972-01-01

    The role of heating from nuclear radiation in design of the NERVA engine is treated. Some components are subjected to very high gamma heating rates in excess of 0.5 Btu/cubic inch/sec in steel in the primary nozzle or 0.25 Btu/cubic inch/sec in aluminum in the pressure vessel. These components must be cooled by a fraction of the liquid hydrogen propellant before it is passed through the core, heated, and expanded out the nozzle as a gas. Other components that are subjected to lower heating rates such as the thrust structure and the disk shield are designed so that they would not require liquid hydrogen cooling. Typical gamma and neutron heating rates, resulting temperatures, and their design consequences are discussed. Calculational techniques used in the nuclear and thermal analyses of the NERVA engine are briefly treated.

  9. Nuclear Instruments and Methods in Physics Research A 477 (2002) 299303 Radiation hard cryogenic silicon detectors

    E-print Network

    Zavrtanik, Marko

    increase of the depletion voltage. When the radiation fluence approaches 1015 n=cm2 ; standard detectors the radiation hardness of silicon detectors is their operation at cryogenic temperatures. Indeed, it has beenNuclear Instruments and Methods in Physics Research A 477 (2002) 299­303 Radiation hard cryogenic

  10. A general approach to increasing the radiation hardness of complex structure oxide scintillation crystals

    Microsoft Academic Search

    M. V. Korzhik

    2003-01-01

    An approach to increasing the radiation hardness of scintillation materials based on complex structure oxide single crystals is proposed. It is shown that damage of the scintillation mechanism and radiation-induced optical absorption are strongly suppressed when a crystal is doped by a specific impurity. The necessary impurity properties are formulated. The proposed approach is illustrated by radiation hardness improvement of

  11. Strategies for Radiation Hardness Testing of Power Semiconductor Devices

    NASA Technical Reports Server (NTRS)

    Soltis, James V. (Technical Monitor); Patton, Martin O.; Harris, Richard D.; Rohal, Robert G.; Blue, Thomas E.; Kauffman, Andrew C.; Frasca, Albert J.

    2005-01-01

    Plans on the drawing board for future space missions call for much larger power systems than have been flown in the past. These systems would employ much higher voltages and currents to enable more powerful electric propulsion engines and other improvements on what will also be much larger spacecraft. Long term human outposts on the moon and planets would also require high voltage, high current and long life power sources. Only hundreds of watts are produced and controlled on a typical robotic exploration spacecraft today. Megawatt systems are required for tomorrow. Semiconductor devices used to control and convert electrical energy in large space power systems will be exposed to electromagnetic and particle radiation of many types, depending on the trajectory and duration of the mission and on the power source. It is necessary to understand the often very different effects of the radiations on the control and conversion systems. Power semiconductor test strategies that we have developed and employed will be presented, along with selected results. The early results that we have obtained in testing large power semiconductor devices give a good indication of the degradation in electrical performance that can be expected in response to a given dose. We are also able to highlight differences in radiation hardness that may be device or material specific.

  12. The role of radiation hard solar cells in minimizing the costs of global satellite communication systems

    NASA Technical Reports Server (NTRS)

    Summers, Geoffrey P.; Walters, Robert J.; Messenger, Scott R.; Burke, Edward A.

    1996-01-01

    An analysis embodied in a PC computer program is presented, which quantitatively demonstrates how the availability of radiation hard solar cells can help minimize the cost of a global satellite communications system. An important distinction between the currently proposed systems, such as Iridium, Odyssey and Ellipsat, is the number of satellites employed and their operating altitudes. Analysis of the major costs associated with implementing these systems shows that operation at orbital altitudes within the earth's radiation belts (10(exp 3) to 10(exp 4)km) can reduce the total cost of a system by several hundred percent, so long as radiation hard components including solar cells can be used. A detailed evaluation of the predicted performance of photovoltaic arrays using several different planar solar cell technologies is given, including commercially available Si and GaAs/Ge, and InP/Si which is currently under development. Several examples of applying the program are given, which show that the end of life (EOL) power density of different technologies can vary by a factor of ten for certain missions. Therefore, although a relatively radiation-soft technology can usually provide the required EOL power by simply increasing the size of the array, the impact upon the total system budget could be unacceptable, due to increased launch and hardware costs. In aggregate, these factors can account for more than a 10% increase in the total system cost. Since the estimated total costs of proposed global-coverage systems range from $1B to $9B, the availability of radiation-hard solar cells could make a decisive difference in the selection of a particular constellation architecture.

  13. Radiation hardness of the storage phosphor europium doped potassium chloride for radiation therapy dosimetry

    SciTech Connect

    Driewer, Joseph P.; Chen, Haijian; Osvet, Andres; Low, Daniel A.; Li, H. Harold [Department of Radiation Oncology, Washington University School of Medicine, 4921 Parkview Place, Campus Box 8224, St. Louis, Missouri 63110 and Nuclear Science and Engineering Institute, University of Missouri, E4431 Lafferre Hall, Columbia, Missouri 65211 (United States); Department of Radiation Oncology, Washington University School of Medicine, 4921 Parkview Place, Campus Box 8224, St. Louis, Missouri 63110 (United States); Department of Materials Science and Engineering, Friedrich-Alexander-University Erlangen-Nuremberg, Martensstrasse 7, Erlangen 91058 (Germany); Department of Radiation Oncology, Washington University School of Medicine, 4921 Parkview Place, Campus Box 8224, St. Louis, Missouri 63110 (United States)

    2011-08-15

    Purpose: An important property of a reusable dosimeter is its radiation hardness, that is, its ability to retain its dosimetric merits after irradiation. The radiation hardness of europium doped potassium chloride (KCl:Eu{sup 2+}), a storage phosphor material recently proposed for radiation therapy dosimetry, is examined in this study. Methods: Pellet-style KCl:Eu{sup 2+} dosimeters, 6 mm in diameter, and 1 mm thick, were fabricated in-house for this study. The pellets were exposed by a 6 MV photon beam or in a high dose rate {sup 137}Cs irradiator. Macroscopic properties, such as radiation sensitivity, dose response linearity, and signal stability, were studied with a laboratory photostimulated luminescence (PSL) readout system. Since phosphor performance is related to the state of the storage centers and the activator, Eu{sup 2+}, in the host lattice, spectroscopic and temporal measurements were carried out in order to explore radiation-induced changes at the microscopic level. Results: KCl:Eu{sup 2+} dosimeters retained approximately 90% of their initial signal strength after a 5000 Gy dose history. Dose response was initially supralinear over the dose range of 100-700 cGy but became linear after 60 Gy. Linearity did not change significantly in the 0-5000 Gy dose history spanned in this study. Annealing high dose history chips resulted in a return of supralinearity and a recovery of sensitivity. There were no significant changes in the PSL stimulation spectra, PSL emission spectra, photoluminescence spectra, or luminescence lifetime, indicating that the PSL signal process remains intact after irradiation but at a reduced efficiency due to reparable radiation-induced perturbations in the crystal lattice. Conclusions: Systematic studies of KCl:Eu{sup 2+} material are important for understanding how the material can be optimized for radiation therapy dosimetry purposes. The data presented here indicate that KCl:Eu{sup 2+} exhibits strong radiation hardness and lends support for further investigations of this novel material.

  14. Radiation hardness of the storage phosphor europium doped potassium chloride for radiation therapy dosimetry

    PubMed Central

    Driewer, Joseph P.; Chen, Haijian; Osvet, Andres; Low, Daniel A.; Li, H. Harold

    2011-01-01

    Purpose: An important property of a reusable dosimeter is its radiation hardness, that is, its ability to retain its dosimetric merits after irradiation. The radiation hardness of europium doped potassium chloride (KCl:Eu2+), a storage phosphor material recently proposed for radiation therapy dosimetry, is examined in this study. Methods: Pellet-style KCl:Eu2+ dosimeters, 6 mm in diameter, and 1 mm thick, were fabricated in-house for this study. The pellets were exposed by a 6 MV photon beam or in a high dose rate 137Cs irradiator. Macroscopic properties, such as radiation sensitivity, dose response linearity, and signal stability, were studied with a laboratory photostimulated luminescence (PSL) readout system. Since phosphor performance is related to the state of the storage centers and the activator, Eu2+, in the host lattice, spectroscopic and temporal measurements were carried out in order to explore radiation-induced changes at the microscopic level. Results: KCl:Eu2+ dosimeters retained approximately 90% of their initial signal strength after a 5000 Gy dose history. Dose response was initially supralinear over the dose range of 100–700 cGy but became linear after 60 Gy. Linearity did not change significantly in the 0–5000 Gy dose history spanned in this study. Annealing high dose history chips resulted in a return of supralinearity and a recovery of sensitivity. There were no significant changes in the PSL stimulation spectra, PSL emission spectra, photoluminescence spectra, or luminescence lifetime, indicating that the PSL signal process remains intact after irradiation but at a reduced efficiency due to reparable radiation-induced perturbations in the crystal lattice. Conclusions: Systematic studies of KCl:Eu2+ material are important for understanding how the material can be optimized for radiation therapy dosimetry purposes. The data presented here indicate that KCl:Eu2+ exhibits strong radiation hardness and lends support for further investigations of this novel material. PMID:21928642

  15. Transition radiation in metal-metal multilayer nanostructures as a medical source of hard x-ray radiation

    E-print Network

    Kaplan, Alexander

    Transition radiation in metal-metal multilayer nanostructures as a medical source of hard x; accepted 20 July 2006; published online 31 August 2006 We show that a periodic metal-metal multilayer nanostructure can serve as an efficient source of hard x-ray transition radiation. Our research effort is aimed

  16. K.K. Gan IWORID08 1 Radiation-Hard/High-Speed Data

    E-print Network

    Gan, K. K.

    radiation level opto-link production is decoupled from module production use PIN/VCSEL arrays-hardness of PIN arrays Radiation-hardness of VCSEL arrays Summary #12;K.K. Gan IWORID08 3 ATLAS Silicon pixel modules transmit signal to/from pixel modules with micro twisted pairs much reduced

  17. Radiation-hard/high-speed parallel optical links

    NASA Astrophysics Data System (ADS)

    Gan, K. K.; Buchholz, P.; Kagan, H. P.; Kass, R. D.; Moore, J.; Smith, D. S.; Wiese, A.; Ziolkowski, M.

    2013-12-01

    We have designed an ASIC for use in a parallel optical engine for a new layer of the ATLAS pixel detector in the initial phase of the LHC luminosity upgrade. The ASIC is a 12-channel Vertical Cavity Surface Emitting Laser (VCSEL) array driver capable of operating up to 5 Gb/s per channel. The ASIC is designed using a 130 nm CMOS process to enhance the radiation-hardness. A scheme for redundancy has also been implemented to allow bypassing of a broken VCSEL. The ASIC also contains a power-on reset circuit that sets the ASIC to a default configuration with no signal steering. In addition, the bias and modulation currents of the individual channels are programmable. We have tested the ASIC and the performance up to 5 Gb/s is satisfactory. Furthermore, we are able to program the bias and modulation currents and to bypass a broken VCSEL channel. We are currently upgrading our design to allow operation at 10 Gb/s per channel yielding an aggregated bandwidth of 120 Gb/s. Preliminary results of the design will be presented.

  18. Radiation-hard/high-speed parallel optical links

    NASA Astrophysics Data System (ADS)

    Gan, K. K.; Buchholz, P.; Kagan, H. P.; Kass, R. D.; Moore, J.; Smith, D. S.; Wiese, A.; Ziolkowski, M.

    2014-11-01

    We have designed an ASIC for use in a parallel optical engine for a new layer of the ATLAS pixel detector in the initial phase of the LHC luminosity upgrade. The ASIC is a 12-channel VCSEL (Vertical Cavity Surface Emitting Laser) array driver capable of operating up to 5 Gb/s per channel. The ASIC is designed using a 130 nm CMOS process to enhance the radiation-hardness. A scheme for redundancy has also been implemented to allow bypassing of a broken VCSEL. The ASIC also contains a power-on reset circuit that sets the ASIC to a default configuration with no signal steering. In addition, the bias and modulation currents of the individual channels are programmable. The performance of the first prototype ASIC up to 5 Gb/s is satisfactory. Furthermore, we are able to program the bias and modulation currents and to bypass a broken VCSEL channel. We are currently upgrading our design to allow operation at 10 Gb/s per channel yielding an aggregated bandwidth of 120 Gb/s. Some preliminary results of the design will be presented.

  19. Microstructural variations in radiation hard and soft oxides observed through electron spin resonance

    NASA Astrophysics Data System (ADS)

    Lenahan, P. M.; Dressendorfer, P. V.

    1983-12-01

    Microstructural variations have been investigated in radiation-hard and -soft oxides, using electron spin resonance. It is observed that the radiation tolerance of hard and soft oxides grown in both steam and dry oxygen is correlated with two 'trivalent silicon' point defects. One trivalent silicon defect, the P(b) center, is responsible for the radiation-induced interface states. The other center, termed E-prime, appears to be the hole trap.

  20. DISCOVERY OF AN EXTRA HARD SPECTRAL COMPONENT IN THE HIGH-ENERGY AFTERGLOW EMISSION OF GRB 130427A

    SciTech Connect

    Tam, Pak-Hin Thomas [Institute of Astronomy and Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Tang Qingwen; Liu Ruoyu; Wang Xiangyu [School of Astronomy and Space Science, Nanjing University, Nanjing 210093 (China); Hou Shujin, E-mail: phtam@phys.nthu.edu.tw, E-mail: xywang@nju.edu.cn [Department of Astronomy and Institute of Theoretical Physics and Astrophysics, Xiamen University, Xiamen, Fujian 361005 (China)

    2013-07-01

    The extended high-energy gamma-ray (>100 MeV) emission which occurs after prompt gamma-ray bursts (GRBs) is usually characterized by a single power-law spectrum, which has been explained as the afterglow synchrotron radiation. The afterglow inverse Compton emission has long been predicted to be able to produce a high-energy component as well, but previous observations have not clearly revealed such a signature, probably due to the small number of >10 GeV photons even for the brightest GRBs known so far. In this Letter, we report on the Fermi Large Area Telescope observations of the >100 MeV emission from the very bright and nearby GRB 130427A. We characterize the time-resolved spectra of the GeV emission from the GRB onset to the afterglow phase. By performing time-resolved spectral fits of GRB 130427A, we found strong evidence of an extra hard spectral component that exists in the extended high-energy emission of this GRB. We argue that this hard component may arise from the afterglow inverse Compton emission.

  1. Radiation hard programmable delay line for LHCb calorimeter upgrade

    NASA Astrophysics Data System (ADS)

    Mauricio, J.; Gascón, D.; Vilasís, X.; Picatoste, E.; Machefert, F.; Lefrancois, J.; Duarte, O.; Beigbeder, C.

    2014-01-01

    This paper describes the implementation of a SPI-programmable clock delay chip based on a Delay Locked Loop (DLL) in order to shift the phase of the LHC clock (25 ns) in steps of 1ns, with less than 5 ps jitter and 23 ps of DNL. The delay lines will be integrated into ICECAL, the LHCb calorimeter front-end analog signal processing ASIC in the near future. The stringent noise requirements on the ASIC imply minimizing the noise contribution of digital components. This is accomplished by implementing the DLL in differential mode. To achieve the required radiation tolerance several techniques are applied: double guard rings between PMOS and NMOS transistors as well as glitch suppressors and TMR Registers. This 5.7 mm2 chip has been implemented in CMOS 0.35 ?m technology.

  2. The role of radiation hard solar cells in minimizing the costs of global satellite communications systems

    NASA Technical Reports Server (NTRS)

    Summers, Geoffrey P.; Walters, Robert J.; Messenger, Scott R.; Burke, Edward A.

    1995-01-01

    An analysis embodied in a PC computer program is presented which quantitatively demonstrates how the availability of radiation hard solar cells can minimize the cost of a global satellite communication system. The chief distinction between the currently proposed systems, such as Iridium Odyssey and Ellipsat, is the number of satellites employed and their operating altitudes. Analysis of the major costs associated with implementing these systems shows that operation within the earth's radiation belts can reduce the total system cost by as much as a factor of two, so long as radiation hard components including solar cells, can be used. A detailed evaluation of several types of planar solar cells is given, including commercially available Si and GaAs/Ge cells, and InP/Si cells which are under development. The computer program calculates the end of life (EOL) power density of solar arrays taking into account the cell geometry, coverglass thickness, support frame, electrical interconnects, etc. The EOL power density can be determined for any altitude from low earth orbit (LEO) to geosynchronous (GEO) and for equatorial to polar planes of inclination. The mission duration can be varied over the entire range planned for the proposed satellite systems. An algorithm is included in the program for determining the degradation of cell efficiency for different cell technologies due to proton and electron irradiation. The program can be used to determine the optimum configuration for any cell technology for a particular orbit and for a specified mission life. Several examples of applying the program are presented, in which it is shown that the EOL power density of different technologies can vary by an order of magnitude for certain missions. Therefore, although a relatively radiation soft technology can be made to provide the required EOL power by simply increasing the size of the array, the impact on the total system budget could be unacceptable, due to increased launch and hardware costs. In aggregate these factors can account for more than a 10% increase in the total system cost. Since the estimated total costs of proposed global coverage systems range from $1 Billion to $9 Billion, the availability of radiation hard solar cells could make a decisive difference in the selection of a particular constellation architecture.

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

    SciTech Connect

    Hargett, Terry W. (L& M Technologies, Inc.); Serkland, Darwin Keith; Blansett, Ethan L.; Geib, Kent Martin; Sullivan, Charles Thomas; Hawkins, Samuel D.; Wrobel, Theodore Frank; Keeler, Gordon Arthur; Klem, John Frederick; Medrano, Melissa R.; Peake, Gregory Merwin; Karpen, Gary D.; Montano, Victoria A. (L& M Technologies, Inc.)

    2003-12-01

    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.

  4. Radiation hardness qualification of PbWO4 scintillation crystals for the CMS Electromagnetic Calorimeter

    E-print Network

    The CMS Electromagnetic Calorimeter Group; P. Adzic; N. Almeida; D. Andelin; I. Anicin; Z. Antunovic; R. Arcidiacono; M. W. Arenton; E. Auffray; S. Argiro; A. Askew; S. Baccaro; S. Baffioni; M. Balazs; D. Bandurin; D. Barney; L. M. Barone; A. Bartoloni; C. Baty; S. Beauceron; K. W. Bell; C. Bernet; M. Besancon; B. Betev; R. Beuselinck; C. Biino; J. Blaha; P. Bloch; A. Borisevitch; A. Bornheim; J. Bourotte; R. M. Brown; M. Buehler; P. Busson; B. Camanzi; T. Camporesi; N. Cartiglia; F. Cavallari; A. Cecilia; P. Chang; Y. H. Chang; C. Charlot; E. A. Chen; W. T. Chen; Z. Chen; R. Chipaux; B. C. Choudhary; R. K. Choudhury; D. J. A. Cockerill; S. Conetti; S. Cooper; F. Cossutti; B. Cox; D. G. Cussans; I. Dafinei; D. R. Da Silva Di Calafiori; G. Daskalakis; A. David; K. Deiters; M. Dejardin; A. De Benedetti; G. Della Ricca; D. Del Re; D. Denegri; P. Depasse; J. Descamps; M. Diemoz; E. Di Marco; G. Dissertori; M. Dittmar; L. Djambazov; M. Djordjevic; L. Dobrzynski; A. Dolgopolov; S. Drndarevic; G. Drobychev; D. Dutta; M. Dzelalija; A. Elliott-Peisert; H. El Mamouni; I. Evangelou; B. Fabbro; J. L. Faure; J. Fay; A. Fedorov; F. Ferri; D. Franci; G. Franzoni; K. Freudenreich; W. Funk; S. Ganjour; S. Gascon; M. Gataullin; F. X. Gentit; A. Ghezzi; A. Givernaud; S. Gninenko; A. Go; B. Gobbo; N. Godinovic; N. Golubev; P. Govoni; N. Grant; P. Gras; M. Haguenauer; G. Hamel de Monchenault; M. Hansen; J. Haupt; H. F. Heath; B. Heltsley; W. Hintz; R. Hirosky; P. R. Hobson; A. Honma; G. W. S. Hou; Y. Hsiung; M. Huhtinen; B. Ille; Q. Ingram; A. Inyakin; P. Jarry; C. Jessop; D. Jovanovic; K. Kaadze; V. Kachanov; S. Kailas; S. K. Kataria; B. W. Kennedy; P. Kokkas; T. Kolberg; M. Korjik; N. Krasnikov; D. Krpic; Y. Kubota; C. M. Kuo; P. Kyberd; A. Kyriakis; M. Lebeau; P. Lecomte; P. Lecoq; A. Ledovskoy; M. Lethuillier; S. W. Lin; W. Lin; V. Litvine; E. Locci; E. Longo; D. Loukas; P. D. Luckey; W. Lustermann; Y. Ma; M. Malberti; J. Malclès; D. Maletic; N. Manthos; Y. Maravin; C. Marchica; N. Marinelli; A. Markou; C. Markou; M. Marone; V. Matveev; C. Mavrommatis; P. Meridiani; P. Milenovic; P. Miné; O. Missevitch; A. K. Mohanty; F. Moortgat; P. Musella; Y. Musienko; A. Nardulli; J. Nash; P. Nedelec; P. Negri; H. B. Newman; A. Nikitenko; F. Nessi-Tedaldi; M. M. Obertino; G. Organtini; T. Orimoto; M. Paganoni; P. Paganini; A. Palma; L. Pant; A. Papadakis; I. Papadakis; I. Papadopoulos; R. Paramatti; P. Parracho; N. Pastrone; J. R. Patterson; F. Pauss; J-P. Peigneux; E. Petrakou; D. G. Phillips II; P. Piroué; F. Ptochos; I. Puljak; A. Pullia; T. Punz; J. Puzovic; S. Ragazzi; S. Rahatlou; J. Rander; P. A. Razis; N. Redaelli; D. Renker; S. Reucroft; P. Ribeiro; C. Rogan; M. Ronquest; A. Rosowsky; C. Rovelli; P. Rumerio; R. Rusack; S. V. Rusakov; M. J. Ryan; L. Sala; R. Salerno; M. Schneegans; C. Seez; P. Sharp; C. H. Shepherd-Themistocleous; J. G. Shiu; R. K. Shivpuri; P. Shukla; C. Siamitros; D. Sillou; J. Silva; P. Silva; A. Singovsky; Y. Sirois; A. Sirunyan; V. J. Smith; F. Stöckli; J. Swain; T. Tabarelli de Fatis; M. Takahashi; V. Tancini; O. Teller; K. Theofilatos; C. Thiebaux; V. Timciuc; C. Timlin; M. Titov; A. Topkar; F. A. Triantis; S. Troshin; N. Tyurin; K. Ueno; A. Uzunian; J. Varela; P. Verrecchia; J. Veverka; T. Virdee; M. Wang; D. Wardrope; M. Weber; J. Weng; J. H. Williams; Y. Yang; I. Yaselli; R. Yohay; A. Zabi; S. Zelepoukine; J. Zhang; L. Y. Zhang; K. Zhu; R. Y. Zhu

    2009-12-22

    Ensuring the radiation hardness of PbWO4 crystals was one of the main priorities during the construction of the electromagnetic calorimeter of the CMS experiment at CERN. The production on an industrial scale of radiation hard crystals and their certification over a period of several years represented a difficult challenge both for CMS and for the crystal suppliers. The present article reviews the related scientific and technological problems encountered.

  5. Influence of design variables on radiation hardness of silicon MINP solar cells

    NASA Technical Reports Server (NTRS)

    Anderson, W. A.; Solaun, S.; Rao, B. B.; Banerjee, S.

    1985-01-01

    Metal-insulator-N/P silicon (MINP) solar cells were fabricated using different substrate resistivity values, different N-layer designs, and different I-layer designs. A shallow junction into an 0.3 ohm-cm substrate gave best efficiency whereas a deeper junction into a 1 to 4 ohm-cm substrate gave improved radiation hardness. I-layer design variation did little to influence radiation hardness.

  6. Transparency and radiation hardness of Cherenkov crystals NaBi(WO 4) 2:Sc

    Microsoft Academic Search

    V. A. Nefedov; B. I. Zadneprovski; E. G. Devitsin; V. A. Kozlov; S. Yu. Potashov; A. Terkulov

    2001-01-01

    The effects of doping the Cherenkov crystal NaBi(WO4)2 with Sc ions on the optical properties and radiation hardness of this crystal have been studied. The radiation hardness of NaBi(WO4)2:Sc is about 3 times higher than that of undoped NaBi(WO4)2. Analytical estimations give the increase of the number of Cherenkov photons by a factor of 1.3, which leads to an improvement

  7. Duplex Treatment of Tools and Components: Previous or Subsequent Electron Beam Hardening of Thermochemically-Treated and PVD Hard-Coated Steels for Tools and Components

    Microsoft Academic Search

    Gundis Sacher; Rolf Zenker; Heinz-Joachim Spies

    2009-01-01

    The tribological properties of tools and components are improved by wear resistant coatings deposited by thermochemical processing (nitriding, nitrocarburizing) or physical vapor deposition (PVD) technologies. The properties gradient between the very hard and brittle layer and the soft, ductile, but hardenable matrix material can be significantly improved by previous or subsequent electron beam hardening (EBH). The hardness of matrix material

  8. Radiation-Pattern Improvement of Patch Antennas Using a Compact Soft/Hard Surface (SHS) Structure

    E-print Network

    Papapolymerou, Ioannis "John"

    Radiation-Pattern Improvement of Patch Antennas Using a Compact Soft/Hard Surface (SHS) Structure performance of patch antennas on a large-size substrate is to construct an artificial periodic structure the concept of the modern SHS structure to improve the radiation pattern of patch antennas. A single square

  9. Radiation chemistry of major food components

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This book chapter summarizes radiolysis of lipids, proteins, carbohydrates and vitamins. The major focuses of the chapter are on recent developments in radiation chemistry and the use of irradiation to reduce undesirable chemicals in foods. Specifically, formation of volatile sulfur compounds from...

  10. Slope effects on shortwave radiation components and net radiation

    NASA Technical Reports Server (NTRS)

    Walter-Shea, Elizabeth A.; Blad, Blaine L.; Hays, Cynthia J.; Mesarch, Mark A.

    1992-01-01

    The main objective of the International Satellite Land Surface Climatology Project (ISLSCP) has been stated as 'the development of techniques that may be applied to satellite observations of the radiation reflected and emitted from the Earth to yield quantitative information concerning land surface climatological conditions.' The major field study, FIFE (the First ISLSCP Field Experiment), was conducted in 1978-89 to accomplish this objective. Four intensive field campaigns (IFC's) were carried out in 1987 and one in 1989. Factors contributing to observed reflected radiation from the FIFE site must be understood before the radiation observed by satellites can be used to quantify surface processes. Analysis since our last report has focused on slope effects on incoming and outgoing shortwave radiation and net radiation from data collected in 1989.

  11. Radiation hardness by design for mixed signal infrared readout circuit applications

    NASA Astrophysics Data System (ADS)

    Gaalema, Stephen; Gates, James; Dobyns, David; Pauls, Greg; Wall, Bruce

    2013-09-01

    Readout integrated circuits (ROICs) to support space-based infrared detection applications often have severe radiation tolerance requirements. Radiation hardness-by-design (RHBD) significantly enhances the radiation tolerance of commercially available CMOS and custom radiation hardened fabrication techniques are not required. The combination of application specific design techniques, enclosed gate architecture nFETs and intrinsic thin oxide radiation hardness of 180 nm process node commercial CMOS allows realization of high performance mixed signal circuits. Black Forest Engineering has used RHBD techniques to develop ROICs with integrated A/D conversion that operate over a wide range of temperatures (40K-300K) to support infrared detection. ROIC radiation tolerance capability for 256x256 LWIR area arrays and 1x128 thermopile linear arrays is presented. The use of 130 nm CMOS for future ROIC RHBD applications is discussed.

  12. Radiation hardness of silicon dioxide dielectric strength in silicon MOS structures

    Microsoft Academic Search

    Tomasz Brozek

    1992-01-01

    The paper deals with the radiation hardness of the Si-SiO2 system -- the basis of advanced MOS VLSI integrated circuits. While the radiation-induced behavior of such crucial Si-SiO2 parameters as surface and oxide charges have been intensively investigated for many years, the radiation aspects of the dielectric strength of thin oxide films has not been investigated. This work describes experiments

  13. Radiation and Shielding Data for Pu-Al Components

    SciTech Connect

    Vernon, P.B.

    2003-01-06

    Radiation intensities associated with the various Pu-Al fuel and target components considered to date for a Cm244 production program vary according to quantity and isotopic content of the Pu used, age of the Pu since separation, and component design. This report summarizes the results of calculations made to determine expected radiation intensities and includes associated shielding data for use in evaluating future shielding requirements for billet preparation and tube extrusion facilities.

  14. A radiation-hard, low-background multiplexer design for spacecraft imager applications

    NASA Technical Reports Server (NTRS)

    Staller, Craig; Ramirez, Luis; Niblack, Curtiss; Blessinger, Michael; Kleinhans, William

    1992-01-01

    A possible multiplexer design for the focal plane for the Cassini Visible and Infrared Mapping Spectrometer (VIMS) is reviewed. The instrument's requirements for the multiplexed array are summarized. The VIMS instrument has a modest radiation-hardness requirement due to the trajectory and planetary environments in which the instrument will be required to operate. The total ionizing dose hardness requirement is a few tens of kilorads. A thin-gate oxide of a few hundred angstroms thickness is to be used. Field hardness is to be achieved by guard bands or hardened dielectric isolation. The design is argued to meet the low-noise and radiation-hardness required for imaging at Saturn. The design is versatile enough to provide double-correlated and double-uncorrelated sampling, which is accomplished in the signal processing electronics outside the focal plane.

  15. A study on the radiation hardness of lead tungstate crystals

    Microsoft Academic Search

    R. Y. Zhu; Q. Deng; H. Newman; C. L. Woody; J. A. Kierstead; S. P. Stoll

    1997-01-01

    This report presents recent progress of a study on the radiation damage in lead tungstate (PbWO4) crystals. The dose rate dependence of radiation damage in PbWO4 has been observed, confirming our early prediction based upon a kinetic model of color centers. An optimization of the oxygen compensation through post-growth thermal annealing, carried out in Shanghai Institute of Ceramics, has led

  16. GaN-Based High Temperature and Radiation-Hard Electronics for Harsh Environments

    NASA Technical Reports Server (NTRS)

    Son, Kyung-ah; Liao, Anna; Lung, Gerald; Gallegos, Manuel; Hatakeh, Toshiro; Harris, Richard D.; Scheick, Leif Z.; Smythe, William D.

    2010-01-01

    We develop novel GaN-based high temperature and radiation-hard electronics to realize data acquisition electronics and transmitters suitable for operations in harsh planetary environments. In this paper, we discuss our research on metal-oxide-semiconductor (MOS) transistors that are targeted for 500 (sup o)C operation and >2 Mrad radiation hardness. For the target device performance, we develop Schottky-free AlGaN/GaN MOS transistors, where a gate electrode is processed in a MOS layout using an Al2O3 gate dielectric layer....

  17. Suzaku broad-band spectrum of 4U 1705-44: Probing the Reflection component in the hard state

    E-print Network

    Di Salvo, T; Matranga, M; Burderi, L; D'Ai, A; Egron, E; Papitto, A; Riggio, A; Robba, N R; Ueda, Y

    2015-01-01

    Iron emission lines at 6.4-6.97 keV, identified with Kalpha radiative transitions, are among the strongest discrete features in the X-ray band. These are one of the most powerful probes to infer the properties of the plasma in the innermost part of the accretion disk around a compact object. In this paper we present a recent Suzaku observation, 100-ks effective exposure, of the atoll source and X-ray burster 4U 1705-44, where we clearly detect signatures of a reflection component which is distorted by the high-velocity motion in the accretion disk. The reflection component consists of a broad iron line at about 6.4 keV and a Compton bump at high X-ray energies, around 20 keV. All these features are consistently fitted with a reflection model, and we find that in the hard state the smearing parameters are remarkably similar to those found in a previous XMM-Newton observation performed in the soft state. In particular, we find that the inner disk radius is Rin = 17 +/- 5 Rg (where Rg is the Gravitational radius...

  18. Axial ion–electron emission microscopy of IC radiation hardness

    Microsoft Academic Search

    B. L. Doyle; G. Vizkelethy; D. S. Walsh; D. Swenson

    2002-01-01

    A new system for performing radiation effects microscopy (REM) has been developed at Sandia National Laboratory in Albuquerque. This system combines two entirely new concepts in accelerator physics and nuclear microscopy. A radio frequency quadrupole (RFQ) linac is used to boost the energy of ions accelerated by a conventional Tandem Van de Graaff–Pelletron to velocities of 1.9 MeV\\/amu. The electronic

  19. Axial ion-electron emission microscopy of IC radiation hardness

    Microsoft Academic Search

    B. L. Doyle; G. Vizkelethy; D. S. Walsh; D. Swenson

    2002-01-01

    A new system for performing radiation effects microscopy (REM) has been developed at Sandia National Laboratory in Albuquerque. This system combines two entirely new concepts in accelerator physics and nuclear microscopy. A radio frequency quadrupole (RFQ) linac is used to boost the energy of ions accelerated by a conventional Tandem Van de Graaff-Pelletron to velocities of 1.9 MeV\\/amu. The electronic

  20. Improvement in radiation hardness of PbWO 4 scintillating crystals by La-doping

    Microsoft Academic Search

    M. Kobayashi; Y. Usuki; M. Ishii; T. Yazawa; K. Hara; M. Tanaka; M. Nikl; S. Baccaro; A. Cecilia; M. Diemoz; I. Dafinei

    1998-01-01

    La-doping significantly improves the radiation hardness of PbWO4 against ?-ray irradiation. The induced absorption coefficient of La-doped samples is as small as 2 m?1 at 420 nm even at 108 rad (106 Gy). The radiation-induced phosphorescence is more than three orders of magnitude less in La-doped PbWO4 crystals than in undoped ones.

  1. Radiation induced modification in nanoscale hardness of ZnO cone structures

    SciTech Connect

    Nagar, Rupali; Mehta, B. R.; Singh, J. P. [Department of Physics, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016 (India); Teki, R. [Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, 110 8th St., Troy, New York 12180 (United States); Koratkar, N. [Department of Mechanical, Aerospace and Nuclear Engineering, Rensselaer Polytechnic Institute, 110 8th St., Troy, New York 12180 (United States); Sathe, V. G. [UGC-DAE, Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452017 (India); Kanjilal, D. [Inter-University Accelerator Centre, Aruna Asaf Ali Marg, Post Box 10502, New Delhi 110067 (India)

    2010-09-15

    In this paper, the effect of ion irradiation on nanoscale hardness of ZnO microcones is reported. The hardness of ZnO cones determined by nanoindentation using atomic force microscope initially increases from 4.7{+-}1.4 to 9.5{+-}1.6 GPa after irradiation with 1.2 MeV Ar{sup +8} ions at an ion fluence of 10{sup 15} ions cm{sup -2} and then decreases with increasing ion fluence. This change in mechanical hardness has been correlated with the residual stress of the sample revealed by Raman peak shift in the E{sub 2}(H) mode. These results show that the generally reported radiation-hard nature of ZnO depends critically on irradiation conditions, especially the irradiation temperature.

  2. Radiation Hardness and Linearity Studies of CVD Diamonds

    E-print Network

    T. Behnke; M. Doucet; N. Ghodbane; A. Imhof

    2002-12-09

    We report on the behavior of CVD diamonds under intense electromagnetic radiation and on the response of the detector to high density of deposited energy. Diamonds have been found to remain unaffected after doses of 10 MGy of MeV-range photons and the diamond response to energy depositions of up to 250 GeV/cm^3 has been found to be linear to better than 2 %. These observations make diamond an attractive detector material for a calorimeter in the very forward region of the detector proposed for TESLA.

  3. Radiation Hardness of a New Magnetic Thin-Film Recording System

    Microsoft Academic Search

    E. J. Hsieh; J. W. Winslow

    1971-01-01

    Magnetic thin-film memory units of a new transient-recording system designed for nuclear data acquisition were tested for radiation hardness. The films were exposed to neutron and gamma doses on the order of 1012 n\\/cm2 and 104 R, respectively. Analog signals stored in the films were photographed using a Suchow powder technique before and after the exposure.

  4. The radiation hardness test on CsI(Tl) crystals for BESIII

    Microsoft Academic Search

    Boxiang Yu; Cheng Yuan; Xiao Cai; Mingyi Dong; Lei Shang; Jian Fang; Lijun Sun; Zhigang Wang; Zhenghua An; Gang Qin; Li Zhou; Junguang Lu; Tao Hu

    2009-01-01

    The radiation hardness of prototype CsI(Tl) crystals has been tested for the electromagnetic calorimeter for the BESIII detector of the BEPCII. Although samples made by one of the producers were found to be soft under irradiation, the problem was quickly improved when this information was fed back. All the tested crystals were found to meet our requirement. At the same

  5. Irradiation facility at the IBR-2 reactor for investigation of material radiation hardness

    NASA Astrophysics Data System (ADS)

    Bulavin, M.; Cheplakov, A.; Kukhtin, V.; Kulagin, E.; Kulikov, S.; Shabalin, E.; Verkhoglyadov, A.

    2015-01-01

    Description of the irradiation facility and available parameters of the neutron and gamma exposures including the maximal integrated doses are presented in the paper. The research capabilities for radiation hardness tests of materials in high intensity beam of fast neutrons at the IBR-2 reactor of the Joint Institute for Nuclear Research in Dubna (Russia) are outlined.

  6. Radiation-hard power electronics for the ATLAS New Small Wheel

    NASA Astrophysics Data System (ADS)

    Ameel, J.; Amidei, D.; Baccaro, S.; Citterio, M.; Cova, P.; Delmonte, N.; Sekhon Edgar, K.; Edgar, R.; Fiore, S.; Lanza, A.; Latorre, S.; Lazzaroni, M.; Yang, Y.

    2015-01-01

    The New Small Wheel (NSW) is an upgrade for the ATLAS detector to provide enhanced triggering and reconstruction of muons in the forward region. The large LV power demands of the NSW necessitate a point-of-load architecture with on-detector power conversion. The radiation load and magnetic field of this environment, while significant, are nevertheless still in the range where commercial-off-the-shelf power devices may suffice. We present studies on the radiation-hardness and magnetic-field tolerance of several candidate buck converters and linear regulators. Device survival and performance are characterized when exposed to gamma radiation, neutrons, protons and magnetic fields.

  7. Effects of plasma-deposited silicon nitride passivation on the radiation hardness of CMOS integrated circuits

    SciTech Connect

    Clement, J. J.

    1980-01-01

    The use of plasma-deposited silicon nitride as a final passivation over metal-gate CMOS integrated circuits degrades the radiation hardness of these devices. The hardness degradation is manifested by increased radiation-induced threshold voltage shifts caused principally by the charging of new interface states and, to a lesser extent, by the trapping of holes created upon exposure to ionizing radiation. The threshold voltage shifts are a strong function of the deposition temperature, and show very little dependence on thickness for films deposited at 300/sup 0/C. There is some correlation between the threshold voltage shifts and the hydrogen content of the PECVD silicon nitride films used as the final passivation layer as a function of deposition temperature. The mechanism by which the hydrogen contained in these films may react with the Si/SiO/sub 2/ interface is not clear at this point.

  8. J. H. Scofield and D. M. Fleetwood, IEEE Transactions on Nuclear Science NS-38, 1567-77 (December 1991). PHYSICAL BASIS FOR NONDESTRUCTIVE TESTS OF MOS RADIATION HARDNESS*

    E-print Network

    Scofield, John H.

    1991). PHYSICAL BASIS FOR NONDESTRUCTIVE TESTS OF MOS RADIATION HARDNESS* John H. Scofield Department noise and channel mobility measurements may be useful in defining nondestructive hardness assurance test. Implications for hardness assurance testing are discussed. 1. Introduction 2. Experimental Details

  9. Comparison of tetrachromic VOF stain to other histochemical staining techniques for characterizing stromal soft and hard tissue components.

    PubMed

    Belaldavar, C; Hallikerimath, S; Angadi, P V; Kale, A D

    2014-11-01

    The components of hard tissues including dentin, enamel, cementum, bone and other calcified deposits, and mature and immature collagen pose problems for identification in routine hematoxylin and eosin (H & E) stained sections. Use of combinations of stains can demonstrate the components of hard tissues and soft tissues distinctly. We assessed the efficacy of the Verde Luz-orange G-acid fuchsin (VOF) stain for differentiating hard and soft connective tissues and compared results with other histochemical staining techniques. Eighty tissue sections comprising developing tooth (30), ossifying fibroma (30) and miscellaneous pathologies (20) expected to contain varying types of calcified tissues were stained with H & E, VOF, and Masson's trichrome (MT). In developing tooth, VOF demonstrated better differentiation of hard tissues, while it was comparable to MT for ossifying fibroma and miscellaneous pathologies. The intensity of staining was greater with VOF than with the other stains studied. VOF stains hard tissue components distinctly and gives good contrast with the surrounding connective tissue. VOF is comparable to MT, but has added advantages including single step staining, rapid and easy procedures, and it distinguishes the maturity of the tissues. PMID:24830362

  10. Radiation Specifications for Fission Power Conversion Component Materials

    NASA Technical Reports Server (NTRS)

    Bowman, Cheryl L.; Shin, E. Eugene; Mireles, Omar R.; Radel, Ross F.; Qualls, A. Louis

    2011-01-01

    NASA has been supporting design studies and technology development that could provide power to an outpost on the moon, Mars, or an asteroid. One power-generation system that is independent of sunlight or power-storage limitations is a fission-based power plant. There is a wealth of terrestrial system heritage that can be transferred to the design and fabrication of a fission power system for space missions, but there are certain design aspects that require qualification. The radiation tolerance of the power conversion system requires scrutiny because the compact nature of a space power plant restricts the dose reduction methodologies compared to those used in terrestrial systems. An integrated research program has been conducted to establish the radiation tolerance of power conversion system-component materials. The radiation limit specifications proposed for a Fission Power System power convertor is 10 Mrad ionizing dose and 5 x 10(exp 14) neutron per square centimeter fluence for a convertor operating at 150 C. Specific component materials and their radiation tolerances are discussed. This assessment is for the power convertor hardware; electronic components are not covered here.

  11. The isotropic-nematic phase transition of tangent hard-sphere chain fluids--pure components.

    PubMed

    van Westen, Thijs; Oyarzún, Bernardo; Vlugt, Thijs J H; Gross, Joachim

    2013-07-21

    An extension of Onsager's second virial theory is developed to describe the isotropic-nematic phase transition of tangent hard-sphere chain fluids. Flexibility is introduced by the rod-coil model. The effect of chain-flexibility on the second virial coefficient is described using an accurate, analytical approximation for the orientation-dependent pair-excluded volume. The use of this approximation allows for an analytical treatment of intramolecular flexibility by using a single pure-component parameter. Two approaches to approximate the effect of the higher virial coefficients are considered, i.e., the Vega-Lago rescaling and Scaled Particle Theory (SPT). The Onsager trial function is employed to describe the orientational distribution function. Theoretical predictions for the equation of state and orientational order parameter are tested against the results from Monte Carlo (MC) simulations. For linear chains of length 9 and longer, theoretical results are in excellent agreement with MC data. For smaller chain lengths, small errors introduced by the approximation of the higher virial coefficients become apparent, leading to a small under- and overestimation of the pressure and density difference at the phase transition, respectively. For rod-coil fluids of reasonable rigidity, a quantitative comparison between theory and MC simulations is obtained. For more flexible chains, however, both the Vega-Lago rescaling and SPT lead to a small underestimation of the location of the phase transition. PMID:23883045

  12. Development of a radiation hard version of the Analog Pipeline Chip APC128

    E-print Network

    Michael Hilgers; Roland Horisberger

    2001-01-17

    The Analog Pipeline Chip (APC) is a low noise, low power readout chip for silicon micro strip detectors with 128 channels containing an analog pipeline of 32 buffers depth. The chip has been designed for operation at HERA with a power dissipation of 300-400 muW per channel and has been used also in several other particle physics experiments. In this paper we describe the development of a radiation hard version of this chip that will be used in the H1 vertex detector for operation at the luminosity upgraded HERA machine. A 128 channel prototyping chip with several amplifier variations has been designed in the radiation hard DMILL technology and measured. The results of various parameter variations are presented in this paper. Based on this, the design choice for the final production version of the APC128-DMILL has been made.

  13. Radiation-hard ASICs for optical data transmission in the ATLAS pixel detector

    E-print Network

    K. K. Gan

    2003-03-13

    We have developed two radiation-hard ASICs for optical data transmission in the ATLAS pixel detector at the LHC at CERN: a driver chip for a Vertical Cavity Surface Emitting Laser (VCSEL) diode for 80 Mbit/s data transmission from the detector, and a Bi-Phase Mark decoder chip to recover the control data and 40 MHz clock received optically by a PIN diode. We have successfully implemented both ASICs in 0.25 um CMOS technology using enclosed layout transistors and guard rings for increased radiation hardness. We present results from prototype circuits and from irradiation studies with 24 GeV protons up to 57 Mrad (1.9 x 10e15 p/cm2).

  14. Radiation hard silicon detectors—developments by the RD48 (ROSE) collaboration

    Microsoft Academic Search

    G. Lindström; M. Ahmed; S. Albergo; P. Allport; D. Anderson; L. Andricek; M. M. Angarano; V. Augelli; N. Bacchetta; P. Bartalini; R. Bates; U. Biggeri; G. M. Bilei; D. Bisello; D. Boemi; E. Borchi; T. Botila; T. J. Brodbeck; M. Bruzzi; T. Budzynski; P. Burger; F. Campabadal; G. Casse; E. Catacchini; A. Chilingarov; P. Ciampolini; V. Cindro; M. J. Costa; D. Creanza; P. Clauws; C Da Via; G. Davies; W De Boer; R Dell’Orso; M De Palma; B. Dezillie; V. Eremin; O. Evrard; G. Fallica; G. Fanourakis; H. Feick; E. Fretwurst; L. Fonseca; J. Fuster; K. Gabathuler; M. Glaser; P. Grabiec; E. Grigoriev; G. Hall; M. Hanlon; F. Hauler; S. Heising; A. Holmes-Siedle; R. Horisberger; G. Hughes; M. Huhtinen; I. Ilyashenko; A. Ivanov; B. K Jones; L. Jungermann; A. Kaminsky; Z. Kohout; G. Kramberger; M. Kuhnke; S. Kwan; F. Lemeilleur; C. Leroy; M. Letheren; Z. Li; T. Ligonzo; V. Linhart; P. Litovchenko; D. Loukas; M. Lozano; Z. Luczynski; G. Lutz; B. MacEvoy; S. Manolopoulos; A. Markou; C. Martinez; A. Messineo; M. Mikuz; M. Moll; E. Nossarzewska; G. Ottaviani; V. Oshea; G. Parrini; D. Passeri; D. Petre; A. Pickford; I. Pintilie; L. Pintilie; S. Pospisil; R. Potenza; C. Raine; J. M Rafi; P. N Ratoff; R. H Richter; P. Riedler; S. Roe; P. Roy; A. Ruzin; A. I. Ryazanov; A. Santocchia; L. Schiavulli; P. Sicho; I. Siotis; T. Sloan; W. Slysz; K. Smith; M. Solanky; B. Sopko; K. Stolze; B Sundby Avset; B. Svensson; C. Tivarus; G. Tonelli; A. Tricomi; S. Tzamarias; G. Valvo; A. Vasilescu; A. Vayaki; E. Verbitskaya; P. Verdini; V. Vrba; S. Watts; E. R Weber; M. Wegrzecki; I. Wegrzecka; P. Weilhammer; R. Wheadon; C. Wilburn; I. Wilhelm; R. Wunstorf; J. Wüstenfeld; J. Wyss; K. Zankel; P. Zabierowski; D Žontar

    2001-01-01

    The RD48 (ROSE) collaboration has succeeded to develop radiation hard silicon detectors, capable to withstand the harsh hadron fluences in the tracking areas of LHC experiments. In order to reach this objective, a defect engineering technique was employed resulting in the development of Oxygen enriched FZ silicon (DOFZ), ensuring the necessary O-enrichment of about 2×1017 O\\/cm3 in the normal detector

  15. Study of the radiation hardness of CsI(Tl) crystals for the BELLE detector

    Microsoft Academic Search

    K. Kazui; A. Watanabe; S. Osone; B. G Cheon; M. Fukushima; H. Hayashii; X. Q Hu; S. Ichizawa; S. Igarashi; H. Ikeda; K. Kaneyuki; M. H Lee; K. Miyabayashi; S. Noguchi; H. Sagawa; A. Satpathy; R. Suzuki; K. Tamai; T. Tsukamoto; Y. Watanabe; X. C Zhong

    1997-01-01

    The radiation hardness of prototype CsI(Tl) crystals has been tested for the barrel electromagnetic calorimeter for the BELLE detector of the KEK B factory. Although samples made by one of the producers were found to be soft under irradiation, the problem was quickly improved when this information was fed back. All the tested crystals were found to meet our requirement.The

  16. Improvement of optical properties and radiation hardness of NaBi(WO 4) 2 Cherenkov crystals

    Microsoft Academic Search

    B. I Zadneprovski; V. A Nefedov; E. V Polyansky; E. G Devitsin; V. A Kozlov; S. Y Potashov; A. R Terkulov

    2002-01-01

    On the basis of the data on melt evaporation while growing NaBi(WO4)2 Cherenkov crystals, the formation of nonstoichiometry and most probable types of dot defects of the crystals have been considered. The influence of melt nonstoichiometry and doping with Sc on optical transmission and radiation hardness of the crystals has been experimentally investigated. The surplus of WO3 has been established

  17. Volumetric density trends (TB/in.3) for storage components: TAPE, hard disk drives, NAND, and Blu-ray

    NASA Astrophysics Data System (ADS)

    Fontana, R. E.; Decad, G. M.; Hetzler, S. R.

    2015-05-01

    Memory storage components, i.e., hard disk drives, tape cartridges, solid state drives using Flash NAND chips, and now optical cartridges using Blu-ray disks, have provided annual increases in memory capacity by decreasing the area of the memory cell associated with the technology of these components. The ability to reduce bit cell sizes is now being limited by nano-technology physics so that in order for component manufacturers to continue to increase component capacity, volumetric enhancements to the storage component are now being introduced. Volumetric enhancements include adding more tape per cartridge, more disk platters per drive, and more layers of memory cells on the silicon NAND substrate or on the optical disk substrate. This paper describes these volumetric strategies, projects density trends at the bit cell level, and projects volumetric trends at the component level in order to forecast future component capacity trends.

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

    NASA Astrophysics Data System (ADS)

    Jakši?, 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.

  19. Investigations on radiation hardness of DEPFET sensors for the Belle II detector

    NASA Astrophysics Data System (ADS)

    Ritter, Andreas; Andricek, Ladislav; Kleinohl, Tobias; Koffmane, Christian; Lütticke, Florian; Marinas, Carlos; Moser, Hans-Günther; Ninkovic, Jelena; Richter, Rainer; Schaller, Gerhard; Schnecke, Martina; Schopper, Florian

    2013-12-01

    In the upgrade of the Belle detector at KEK (Tsukuba, Japan) the two innermost layers of the vertex detector will be realized by a pixel detector (PXD) consisting of DEPFET (DEpleted P-channel Field Effect Transistor) matrices. As the position of the detector will be very close to the beam pipe, it will suffer from intense radiation levels. The main radiation background is the luminosity related 4-fermion final state radiation, which damages the silicon bulk material and the silicon dioxide from the gate contacts. With the dose expected at Belle II, the DEPFET suffers mainly from additional leakage current and increase in noise. In addition, defects in the silicon dioxide change transistor parameters, e.g. the threshold voltage. We will show results on the hardness factor of electrons after a 10 MeV electron irradiation which was performed in the dose and energy range relevant for the PXD. In addition, we present X-ray irradiations of DEPFET equivalent test structures and compare radiation hardness for different oxide parameters in the prototype production.

  20. A comparative study of the radiation hardness of silicon carbide using light ions

    NASA Astrophysics Data System (ADS)

    Lee, K. K.; Ohshima, T.; Saint, A.; Kamiya, T.; Jamieson, D. N.; Itoh, H.

    2003-09-01

    6H-silicon carbide (SiC) schottky diodes were irradiated at room temperature (RT) with proton, alpha and carbon particles to fluences in the range of 10 8-10 13 ions/cm 2. Both radiative and non-radiative traps are generated due to damage caused by the incident ions. Ionluminescence performed at RT revealed that radiative traps with photon emission energy of 2.32 eV appear after radiation. Electroluminescence measurement indicated that at RT the influence of non-radiative defects dominated over the radiative ones. Ion beam induced charge collection was used to investigate the charge collection efficiency of these diodes. Reduction in the charge pulse height is compared with calculation of non-ionising energy loss (NIEL). NIEL is a good measure of the displacement damage introduced in SiC materials by ionising particles. There is no significant difference in the radiation hardness of n-type and p-type 6H-SiC schottky diodes when irradiated with 2 MeV alpha particles.

  1. On the nature of the sources of hard pulse X-ray radiation

    NASA Technical Reports Server (NTRS)

    Shklovskiy, I. S.

    1978-01-01

    Besides the identified sources of cosmic pulse X-ray radiation with globular clusters NGC 6624, NGC 1851 and MXB 1730-335 several new identifications were made. The source in Norma was probably identified with globular cluster NGC 5927, the source in Aquila with globular cluster NGC 6838 (M71), and the source in Puppis with globular cluster NGC 2298. Gamma pulses discovered by the Vela satellites and X-ray pulses thoroughly measured by the SAS-3, Ariel-5, and ANS satellites are thought to be the same phenomenon. The sources of such a radiation must be some kind of peculiarity at the central part of globular clusters; it is most probably a massive black hole. The sources of hard pulse radiation which cannot be identified with globular clusters are considered to be a new kind of galactic object, invisible globular clusters, which are naked nuclei of globular clusters.

  2. Radiation hardness trends in new microelectronic technologies for the readout of semiconductor detectors

    NASA Astrophysics Data System (ADS)

    Re, Valerio

    2013-12-01

    The semiconductor detector community is taking advantage of the most recent developments in the field of microelectronics for the design of high performance readout chips. Commercial CMOS foundries are progressing towards an aggressive scaling of the device feature size; 3D integration of two or more CMOS layers might provide an alternative or additional way to increase functional density and improve the performance of the detector system. On the other hand, advanced applications of semiconductor detectors in high energy physics, photon science and space experiments require that sensors and front-end electronics stand high levels of radiation. This paper reviews the main mechanisms that influence the radiation tolerance of nanoscale CMOS devices. This provides the basis for a discussion of the impact of radiation hardness criteria on the design and technology choices for microelectronic chips in new semiconductor detector systems.

  3. Radiation Hardness Tests of SiPMs for the JLab Hall D Barrel Calorimeter

    SciTech Connect

    Yi Qiang, Carl Zorn, Fernando Barbosa, Elton Smith

    2013-01-01

    We report on the measurement of the neutron radiation hardness of silicon photomultipliers (SiPMs) manufactured by Hamamatsu Corporation in Japan and SensL in Ireland. Samples from both companies were irradiated by neutrons created by a 1 GeV electron beam hitting a thin lead target at Jefferson Lab Hall A. More tests regarding the temperature dependence of the neutron radiation damage and self-annealing were performed on Hamamatsu SiPMs using a calibrated Am–Be neutron source from the Jefferson Lab Radiation Control group. As the result of irradiation both dark current and dark rate increase linearly as a function of the 1 MeV equivalent neutron fluence and a temperature dependent self-annealing effect is observed

  4. Isotropic-nematic phase equilibria of hard-sphere chain fluids—Pure components and binary mixtures

    NASA Astrophysics Data System (ADS)

    Oyarzún, Bernardo; van Westen, Thijs; Vlugt, Thijs J. H.

    2015-02-01

    The isotropic-nematic phase equilibria of linear hard-sphere chains and binary mixtures of them are obtained from Monte Carlo simulations. In addition, the infinite dilution solubility of hard spheres in the coexisting isotropic and nematic phases is determined. Phase equilibria calculations are performed in an expanded formulation of the Gibbs ensemble. This method allows us to carry out an extensive simulation study on the phase equilibria of pure linear chains with a length of 7 to 20 beads (7-mer to 20-mer), and binary mixtures of an 8-mer with a 14-, a 16-, and a 19-mer. The effect of molecular flexibility on the isotropic-nematic phase equilibria is assessed on the 8-mer+19-mer mixture by allowing one and two fully flexible beads at the end of the longest molecule. Results for binary mixtures are compared with the theoretical predictions of van Westen et al. [J. Chem. Phys. 140, 034504 (2014)]. Excellent agreement between theory and simulations is observed. The infinite dilution solubility of hard spheres in the hard-sphere fluids is obtained by the Widom test-particle insertion method. As in our previous work, on pure linear hard-sphere chains [B. Oyarzún, T. van Westen, and T. J. H. Vlugt, J. Chem. Phys. 138, 204905 (2013)], a linear relationship between relative infinite dilution solubility (relative to that of hard spheres in a hard-sphere fluid) and packing fraction is found. It is observed that binary mixtures greatly increase the solubility difference between coexisting isotropic and nematic phases compared to pure components.

  5. Isotropic-nematic phase equilibria of hard-sphere chain fluids-Pure components and binary mixtures.

    PubMed

    Oyarzún, Bernardo; van Westen, Thijs; Vlugt, Thijs J H

    2015-02-14

    The isotropic-nematic phase equilibria of linear hard-sphere chains and binary mixtures of them are obtained from Monte Carlo simulations. In addition, the infinite dilution solubility of hard spheres in the coexisting isotropic and nematic phases is determined. Phase equilibria calculations are performed in an expanded formulation of the Gibbs ensemble. This method allows us to carry out an extensive simulation study on the phase equilibria of pure linear chains with a length of 7 to 20 beads (7-mer to 20-mer), and binary mixtures of an 8-mer with a 14-, a 16-, and a 19-mer. The effect of molecular flexibility on the isotropic-nematic phase equilibria is assessed on the 8-mer+19-mer mixture by allowing one and two fully flexible beads at the end of the longest molecule. Results for binary mixtures are compared with the theoretical predictions of van Westen et al. [J. Chem. Phys. 140, 034504 (2014)]. Excellent agreement between theory and simulations is observed. The infinite dilution solubility of hard spheres in the hard-sphere fluids is obtained by the Widom test-particle insertion method. As in our previous work, on pure linear hard-sphere chains [B. Oyarzún, T. van Westen, and T. J. H. Vlugt, J. Chem. Phys. 138, 204905 (2013)], a linear relationship between relative infinite dilution solubility (relative to that of hard spheres in a hard-sphere fluid) and packing fraction is found. It is observed that binary mixtures greatly increase the solubility difference between coexisting isotropic and nematic phases compared to pure components. PMID:25681939

  6. Development of radiation-hard optical links for the CMS tracker at CERN

    SciTech Connect

    Vasey, F.; Arbet-Engels, V.; Cervelli, G.; Gill, K.; Grabit, R.; Mommaert, C.; Stefanini, G. [CERN, Geneva (Switzerland). ECP Div.] [CERN, Geneva (Switzerland). ECP Div.; Batten, J.; Troska, J. [Imperial Coll., London (United Kingdom)] [Imperial Coll., London (United Kingdom)

    1998-06-01

    A radiation-hard optical link is under development for readout and control of the tracking detector in the future CMS experiment at the CERN Large Hadron Collider. The authors present the optical system architecture based on edge-emitting InGaAsP laser-diode transmitters operating at a wavelength of 1.3 {micro}m, single mode fiber ribbons, multi-way connectors and InGaAsP in photodiode receivers. They report on radiation hardness tests of lasers, photodiodes, fibers and connectors. Increases of laser threshold and pin leakage currents with hadron fluence have been observed together with decreases in laser slope-efficiency and photodiode responsivity. Short lengths of single-mode optical fiber and multi-way connectors have been found to be little affected by radiation damage. They analyze the analog and digital performance of prototype optical links transmitting data generated at a 40 MSample/s rate. Distortion, settling time, bandwidth, noise, dynamic range and bit-error-rate results are discussed.

  7. Radiation-hard active CMOS pixel sensors for HL-LHC detector upgrades

    NASA Astrophysics Data System (ADS)

    Backhaus, Malte

    2015-02-01

    The luminosity of the Large Hadron Collider (LHC) will be increased during the Long Shutdown of 2022 and 2023 (LS3) in order to increase the sensitivity of its experiments. A completely new inner detector for the ATLAS experiment needs to be developed to withstand the extremely harsh environment of the upgraded, so-called High-Luminosity LHC (HL-LHC). High radiation hardness as well as granularity is mandatory to cope with the requirements in terms of radiation damage as well as particle occupancy. A new silicon detector concept that uses commercial high voltage and/or high resistivity full complementary metal-oxide-semiconductor (CMOS) processes as active sensor for pixel and/or strip layers has risen high attention, because it potentially provides high radiation hardness and granularity and at the same time reduced price due to the commercial processing and possibly relaxed requirements for the hybridization technique. Results on the first prototypes characterized in a variety of laboratory as well as test beam environments are presented.

  8. Plasma dynamics and generation of hard radiations in experiments with cylindrical Z-pinches

    SciTech Connect

    Matveev, Yu. V. [Academy of Sciences of Abkhazia, Sukhum Physicotechnical Institute, Abkhazia (Georgia)

    2010-03-15

    A survey of experimental studies on the generation of hard ionizing radiations from dynamic cylindrical Z-pinches is presented. Comprehensive experimental data do not confirm the hypothesis that charged particles responsible for the generation of hard radiations (neutrons and X-rays) are accelerated in short-scale Z-pinch necks (m = 0). Analysis of the experimental data indicates that, in discharges in pure hydrogen and deuterium, these particles are most probably accelerated in the axial direction along H{sub {phi} {approx}} 0 lines by the induction electric field generated during the initiation of the secondary near-wall breakdown, which disconnects the pinch from the power supply. In discharges excited in heavy gases and at high initial current growth rates (I{sub 0} {>=} 10{sup 12} A/s) in experiments with hydrogen and deuterium contaminated with admixtures arriving from the chamber wall, there is an additional acceleration mechanism related to the growth of the resistance of a radiatively cooled Z-pinch.

  9. The X-ray emission from Nova V382 Velorum I. The hard component observed with BeppoSAX

    E-print Network

    Greiner, Jochen

    The X-ray emission from Nova V382 Velorum ­ I. The hard component observed with BeppoSAX M. Orio,1SAX observations of Nova Velorum 1999 (V382 Vel), carried out in a broad X-ray band covering 0:1­300 keV only 15 d after the discovery and again after 6 months. The nova was detected at day 15 with the Beppo

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

    NASA Astrophysics Data System (ADS)

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

    2010-11-01

    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 7×10 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.

  11. Radiation hardness tests of double-sided 3D strip sensors with passing-through columns

    NASA Astrophysics Data System (ADS)

    Dalla Betta, Gian-Franco; Betancourt, Christopher; Boscardin, Maurizio; Giacomini, Gabriele; Jakobs, Karl; Kühn, Susanne; Lecini, Besnik; Mendicino, Roberto; Mori, Riccardo; Parzefall, Ulrich; Povoli, Marco; Thomas, Maira; Zorzi, Nicola

    2014-11-01

    This paper deals with a radiation hardness study performed on double-sided 3D strip sensors with passing-through columns. Selected results from the characterization of the irradiated sensors with a beta source and a laser setup are reported and compared to pre-irradiation results and to TCAD simulations. The sensor performance in terms of signal efficiency is found to be in good agreement with that of other 3D sensors irradiated at the same fluences and tested under similar experimental conditions.

  12. Silicon Photo-Multiplier radiation hardness tests with a beam controlled neutron source

    E-print Network

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

    2010-06-08

    We report radiation hardness tests performed at the Frascati Neutron Generator on silicon Photo-Multipliers, 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 performances have been recorded during the neutron irradiation and a gradual deterioration of their properties was found to happen already after an integrated fluence of the order of 10^8 1-MeV-equivalent neutrons per cm^2.

  13. Designing radiation hardened CMOS microelectronic components at commercial foundries: space and terrestrial radiation environments and device and circuit techniques to mitigate radiation effects

    Microsoft Academic Search

    R. Locoe

    2005-01-01

    Summary form only given. When using microelectronic components in a radiation environment, such as those experienced by components in space, components used in nuclear reactors and components used for high-energy physics experiments, specific degradation mechanisms must be mitigated to assure proper component performance over the lifetime of the part. Over the last thirty years, the preferred method for fabricating radiation-hardened

  14. Radiative corrections for electron proton elastic scattering taking into account high orders and hard photon emission

    E-print Network

    E. A. Kuraev; A. I. Ahmadov; Yu. M. Bystritskiy; E. Tomasi-Gustafsson

    2013-11-02

    We investigate the effect of high order radiative corrections in unpolarized electron proton elastic scattering and compare with the calculations at lowest order, which are usually applied to experimental data. Particular attention is devoted to the $\\epsilon$ dependence of radiative corrections, which is directly related to the electric proton form factor. We consider in particular the effects of the interference terms for soft and hard photon emission. Both quadratic amplitude describing the collinear emission along the scattered electron as well as the interference with the amplitudes of emission from the initial electron and the emission from protons are important in leading and next to leading approximation and they may compensate in particular kinematical conditions.

  15. Radiation Hardness of Silicon Detectors Manufactured on Epitaxial Material and FZ Bulk Enriched with Oxygen, Carbon, Tin and Platinum

    NASA Astrophysics Data System (ADS)

    Ruzin, A.; Casse, G.; Glaser, M.; Lemeilleur, F.; Talamonti, R.; Watts, S.; Zanet, A.; ROSE Collaboration-RD48

    1999-08-01

    Recent results on the radiation hardness of silicon detectors fabricated on epitaxial and float zone bulk silicon enriched by various impurities, such as carbon, oxygen, tin and platinum are reported. A new methodology of measurements of electrical properties of the devices has been utilized in the experiment. It has been shown that in the case of irradiation by protons, oxygen enriched silicon has better radiation hardness than standard float zone silicon. The carbon enriched silicon detectors, on the other hand, exhibited significantly inferior radiation hardness compared to standard detectors. This study shows for the first time, a violation of the widely used narmalization technique of the various particle irradiations by NIEL coefficients. The study has been carried out in the framework of the RD48 (ROSE) collaboration, which studies the radiation hardening of silicon detectors.

  16. A high frame rate, 16 million pixels, radiation hard CMOS sensor

    NASA Astrophysics Data System (ADS)

    Guerrini, N.; Turchetta, R.; Van Hoften, G.; Henderson, R.; McMullan, G.; Faruqi, A. R.

    2011-03-01

    CMOS sensors provide the possibility of designing detectors for a large variety of applications with all the benefits and flexibility of the widely used CMOS process. In this paper we describe a novel CMOS sensor designed for transmission electron microscopy. The overall design consists of a large 61 × 63 mm2 silicon area containing 16 million pixels arranged in a 4K × 4K array, with radiation hard geometry. All this is combined with a very fast readout, the possibility of region of interest (ROI) readout, pixel binning with consequent frame rate increase and a dynamic range close to 12 bits. The high frame rate has been achieved using 32 parallel analogue outputs each one operating at up to 20 MHz. Binning of pixels can be controlled externally and the flexibility of the design allows several possibilities, such as 2 × 2 or 4 × 4 binning. Other binning configurations where the number of rows and the number of columns are not equal, such as 2 × 1 or 2 × 4, are also possible. Having control of the CMOS design allowed us to optimise the pixel design, in particular with regard to its radiation hardness, and to make optimum choices in the design of other regions of the final sensor. An early prototype was also designed with a variety of geometries in order to optimise the readout structure and these are presented. The sensor was manufactured in a 0.35 ?m standard CMOS process.

  17. Distribution functions of multi-component fluid mixtures of hard spheres

    Microsoft Academic Search

    E. W. Grundke; D. Henderson

    1972-01-01

    A simple algorithm for obtaining accurate pair distribution functions gij of hard-sphere mixtures is proposed. This generalizes the pure-fluid procedure of Verlet and Weis for improving the Percus-Yevick distribution functions. Two theorems are proved concerning the distribution functions yij=exp (uij\\/kT)gij, and an approximation for these functions is proposed. Finally, a method for computing direct correlation functions, given the pair distribution

  18. EVIDENCE FOR A PHOTOSPHERIC COMPONENT IN THE PROMPT EMISSION OF THE SHORT GRB 120323A AND ITS EFFECTS ON THE GRB HARDNESS-LUMINOSITY RELATION

    SciTech Connect

    Guiriec, S.; McEnery, J.; Gehrels, N. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Daigne, F.; Hascoeet, R.; Mochkovitch, R. [Institut d'Astrophysique de Paris UMR 7095 Universite Pierre et Marie Curie-Paris 06 (France); CNRS 98 bis bd Arago, F-75014 Paris (France); Vianello, G. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Ryde, F. [Department of Physics, Royal Institute of Technology, AlbaNova, SE-106 91 Stockholm (Sweden); Kouveliotou, C. [Office of Science and Technology, ZP12, NASA/Marshall Space Flight Center, Huntsville, AL 35812 (United States); Xiong, S.; Bhat, P. N.; Burgess, J. M. [University of Alabama in Huntsville, NSSTC, 320 Sparkman Drive, Huntsville, AL 35805 (United States); Foley, S.; McGlynn, S. [UCD School of Physics, University College Dublin, Dublin 4 (Ireland); Gruber, D., E-mail: sylvain.guiriec@nasa.gov [Max-Planck-Institut fuer extraterrestrische Physik, Giessenbachstrasse 1, D-85748 Garching (Germany)

    2013-06-10

    The short GRB 120323A had the highest flux ever detected with the Gamma-Ray Burst Monitor on board the Fermi Gamma-Ray Space Telescope. Here we study its remarkable spectral properties and their evolution using two spectral models: (1) a single emission component scenario, where the spectrum is modeled by the empirical Band function (a broken power law), and (2) a two-component scenario, where thermal (a Planck-like function) emission is observed simultaneously with a non-thermal component (a Band function). We find that the latter model fits the integrated burst spectrum significantly better than the former, and that their respective spectral parameters are dramatically different: when fit with a Band function only, the E{sub peak} of the event is unusually soft for a short gamma-ray burst (GRB; 70 keV compared to an average of 300 keV), while adding a thermal component leads to more typical short GRB values (E{sub peak} {approx} 300 keV). Our time-resolved spectral analysis produces similar results. We argue here that the two-component model is the preferred interpretation for GRB 120323A based on (1) the values and evolution of the Band function parameters of the two component scenario, which are more typical for a short GRB, and (2) the appearance in the data of a significant hardness-intensity correlation, commonly found in GRBs, when we employee two-component model fits; the correlation is non-existent in the Band-only fits. GRB 110721A, a long burst with an intense photospheric emission, exhibits the exact same behavior. We conclude that GRB 120323A has a strong photospheric emission contribution, observed for the first time in a short GRB. Magnetic dissipation models are difficult to reconcile with these results, which instead favor photospheric thermal emission and fast cooling synchrotron radiation from internal shocks. Finally, we derive a possibly universal hardness-luminosity relation in the source frame using a larger set of GRBs (L{sub i}{sup Band} = (1.59 {+-} 0.84) x 10{sup 50} (E{sub peak,i}){sup 1.33{+-}0.07} erg s{sup -1}), which could be used as a possible redshift estimator for cosmology.

  19. Prestressing Shock Resistant Mechanical Components and Mechanisms Made from Hard, Superelastic Materials

    NASA Technical Reports Server (NTRS)

    DellaCorte, Christopher (Inventor)

    2014-01-01

    A method and an apparatus confer full superelastic properties to the active surface of a mechanical component constructed of a superelastic material prior to service. A compressive load is applied to the active surface of the mechanical component followed by removing the compressive load from the active surface whereby substantially all load strain is recoverable after applying and removing of subsequent compressive loads.

  20. A distributed hard real-time Java system for high mobility components

    E-print Network

    Rho, Sangig

    2005-02-17

    In this work we propose a methodology for providing real-time capabilities to component-based, on-the-fly recon?gurable, distributed systems. In such systems, software components migrate across computational resources at run-time to allow...

  1. Electromagnetic crystal based terahertz thermal radiators and components

    NASA Astrophysics Data System (ADS)

    Wu, Ziran

    This dissertation presents the investigation of thermal radiation from three-dimensional electromagnetic crystals (EMXT), as well as the development of a THz rapid prototyping fabrication technique and its application in THz EMXT components and micro-system fabrication and integration. First, it is proposed that thermal radiation from a 3-D EMXT would be greatly enhanced at the band gap edge frequency due to the redistribution of photon density of states (DOS) within the crystal. A THz thermal radiator could thus be built upon a THz EMXT by utilizing the exceptional emission peak(s) around its band gap frequency. The thermal radiation enhancement effects of various THz EMXT including both silicon and tungsten woodpile structures (WPS) and cubic photonic cavity (CPC) array are explored. The DOS of all three structures are calculated, and their thermal radiation intensities are predicted using Planck's Equation. These calculations show that the DOS of the silicon and tungsten WPS can be enhanced by a factor of 11.8 around 364 GHz and 2.6 around 406 GHz respectively, in comparison to the normal blackbody radiation at same frequencies. An enhancement factor of more than 100 is obtained in calculation from the CPC array. A silicon WPS with a band gap around 200 GHz has been designed and fabricated. Thermal emissivity of the silicon WPS sample is measured with a control blackbody as reference. And enhancements of the emission from the WPS over the control blackbody are observed at several frequencies quite consistent with the theoretical predictions. Second, the practical challenge of THz EMXT component and system fabrication is met by a THz rapid prototyping technique developed by us. Using this technique, the fabrications of several EMXTs with 3D electromagnetic band gaps in the 100-400 GHz range are demonstrated. Characterization of the samples via THz Time-domain Spectroscopy (THz-TDS) shows very good agreement with simulation, confirming the build accuracy of this prototyping approach. Third, an all-dielectric THz waveguide is designed, fabricated and characterized. The design is based on hollow-core EMXT waveguide, and the fabrication is implemented with the THz prototyping method. Characterization results of the waveguide power loss factor show good consistency with the simulation, and waveguide propagation loss as low as 0.03 dB/mm at 105 GHz is demonstrated. Several design parameters are also varied and their impacts on the waveguide performance investigated theoretically. Finally, a THz EMXT antenna based on expanding the defect radius of the EMXT waveguide to a horn shape is proposed and studied. The boresight directivity and main beam angular width of the optimized EMXT horn antenna is comparable with a copper horn antenna of the same dimensions at low frequencies, and much better than the copper horn at high frequencies. The EMXT antenna has been successfully fabricated via the same THz prototyping, and we believe this is the first time an EMXT antenna of this architecture is fabricated. Far-field measurement of the EMXT antenna radiation pattern is undergoing. Also, in order to integrate planar THz solid-state devices (especially source and detector) and THz samples under test with the potential THz micro-system fabricate-able by the prototyping approach, an EMXT waveguide-to-microstrip line transition structure is designed. The structure uses tapered solid dielectric waveguides on both ends to transit THz energy from the EMXT waveguide defect onto the microstrip line. Simulation of the transition structure in a back-to-back configuration yields about -15 dB insertion loss mainly due to the dielectric material loss. The coupling and radiation loss of the transition structure is estimated to be -2.115 dB. The fabrication and characterization of the transition system is currently underway. With all the above THz components realized in the future, integrated THz micro-systems manufactured by the same prototyping technique will be achieved, with low cost, high quality, self-sufficiency, and great customizability.

  2. Effect of surface preparation on the radiation hardness of high-dielectric constant gate dielectric

    NASA Astrophysics Data System (ADS)

    Tsui, Bing-Yue; Su, Ting-Ting; Shew, Bor-Yuan; Huang, Yang-Tung

    2013-03-01

    Effect of surface preparation on the radiation hardness of MOS devices with high dielectric constant gate dielectric of HfO2 and metal gate of TiN is studied using extreme ultra-violet (EUV) light as the radiation source. Three kinds of surface treatment including HF-last, chemical-oxidation, and rapid-thermal-oxidation were evaluated. Among them, chemical-oxidation exhibits the best radiation hardiness in terms of interface traps and border traps. The state-of-the-art MOSFET with a thin high-k dielectric and a high quality chemical oxide interfacial layer shows that the degradation of subthreshold swing is more severe than degradation of threshold voltage. However, the overall degradation is less than 6% even after EUV irradiation to a total dose of 580 mJ/cm2. Off-state current degradation is observed due to the generation of oxide traps and interface traps at the isolation region. This phenomenon does not occur in the conventional optical lithography process but should be considered if EUV lithography is used.

  3. Influence of different components in a TPV PP/EPDM based with low hardness

    NASA Astrophysics Data System (ADS)

    Gheller, J.; Jacobi, M. M.

    2014-05-01

    Thermoplastic vulcanizates (TPVs) are a class of polymeric material obtained by dynamic vulcanization of an elastomer in a melted thermoplastic matrix. This work intend to evaluate different variables in the production of low hardness TPVs made of polypropylene (PP) and ethylene propylene rubber (EPDM), as well the optimization of the variables looking for TPVs with improved performance. In the Study I the influence of PP crystallinity were evaluated, in the Study II the effects of different amounts of dicumyl peroxide (DCP) were evaluated and in the Study III the amount of the phenolic resin were evaluated. This extended abstract presents, in a more detailed way, the results considering the curative phenolic resin content (Study III). The others results and discussions are briefly described in the results and discussions section. The compounds were obtained in a closed mixing chamber and their processability properties, swelling, hardness and tensile strength were evaluated. With the results obtained were possible to evaluate the influence of different ingredients in the TPVs properties. The results were discussed and presented looking for a better understanding of the influence of this variable in the final product, as well the correlation between then.

  4. First study of radiation hardness of lead tungstate crystals at low temperatures

    NASA Astrophysics Data System (ADS)

    Semenov, P. A.; Uzunian, A. V.; Davidenko, A. M.; Derevschikov, A. A.; Goncharenko, Y. M.; Kachanov, V. A.; Khodyrev, V. Y.; Meschanin, A. P.; Minaev, N. G.; Mochalov, V. V.; Melnick, Y. M.; Ryazantsev, A. V.; Vasiliev, A. N.; Burachas, S. F.; Ippolitov, M. S.; Manko, V.; Vasiliev, A. A.; Mochalov, A. V.; Novotny, R.; Tamulaitis, G.

    2007-11-01

    The electromagnetic calorimeter of PANDA at the FAIR facility will rely on the operation of lead tungstate (PbWO 4, PWO) scintillating crystals at temperatures near -25C to provide sufficient resolution for photons in the energy range from 8 GeV down to 10 MeV. The radiation hardness of PWO crystals was studied at the IHEP (Protvino) irradiation facility in the temperature range from +20C (room temperature) down to -23C. These studies have indicated significantly different behavior in the time evolution of the damaging processes well below room temperature. Different signal loss levels at the same dose rate but at different temperatures were observed. The effect of a deep suppression of the crystal recovery process at temperatures below 0C has been seen.

  5. Novel Si ion implantation technique for improving the radiation hardness of SOI pseudo-MOS transistor

    NASA Astrophysics Data System (ADS)

    Zhang, Yanwei; Huang, Huixiang; Bi, Dawei; Tang, Minghua; Zhang, Zhengxuan

    2014-01-01

    The pseudo-MOS transistor is a quick and effective technique for characterizing the electrical properties of silicon-on-insulator (SOI) wafer. We investigated the total ionizing dose (TID) response of pseudo-MOS transistors fabricated on SOI wafers hardened by single or multiple step Si ion implantation. It is demonstrated that the two Si ion implantation methods can both improve the radiation hardness of SOI wafers owing to the generation of deep electron traps in the buried oxide (BOX). However, the lattice damage of top silicon film caused by the single step implantation compared with the multiple degenerates the electrical properties of transistors, especially for the sub-threshold swing. The high resolution transmission electron microscopy (HRTEM) was used to observe the lattice quality.

  6. Radiation hard fiber optic thermo-hygrometers for relative humidity detection in the CMS experiment at CERN

    NASA Astrophysics Data System (ADS)

    Berruti, G.; Consales, M.; Giordano, M.; Buontempo, S.; Breglio, G.; Makovec, A.; Petagna, P.; Cusano, A.

    2014-05-01

    This work investigates the performances and the radiation hardness capability of optical thermo-hygrometers based on Fiber Bragg Gratings (FBG) technology for humidity monitoring in the Compact Muon Solenoid experiment (CMS) at CERN, in Geneva. Extensive characterizations in terms of sensitivity, repeatability and accuracy on 80 specially produced polyimide-coated FBG sensors and 80 commercial temperature FBG sensors are presented. Progressive irradiation campaigns with ?- ionizing radiations were also performed. Results showed that the sensors sensitivity is unchanged after each radiation exposure; while the wavelength peak exhibits a radiation-induced shift. The saturation properties of this shift are discussed.

  7. Mechanical properties of lunar materials under anhydrous, hard vacuum conditions: applications of lunar glass structural components

    SciTech Connect

    Blacic, J.D.

    1984-01-01

    Lunar materials and derivatives such as glass may possess very high tensile strengths compared to equivalent materials on earth because of the absence of hydrolytic weakening processes on the moon and in the hard vacuum of free space. Hydrolyzation of Si-O bonds at crack tips or dislocations reduces the strength of silicates by about an order of magnitude in earth environments. However, lunar materials are extremely anhydrous and hydrolytic weakening will be suppressed in free space. Thus, the geomechanical properties of the moon and engineering properties of lunar silicate materials in space environments will be very different than equivalent materials under earth conditions where the action of water cannot be conveniently avoided. Possible substitution of lunar glass for structural metals in a variety of space engineering applications enhances the economic utilization of the moon. 26 references, 3 figures, 2 tables.

  8. From Exploratory Synthesis to Hard Radiation Detection: Crystal Growth and Characterization of Chalcogenide and Chalcohalide Materials

    NASA Astrophysics Data System (ADS)

    Nguyen, Sandy Linhsa

    In the first half of this thesis work, exploratory synthesis of materials using mixed polychalcogenide fluxes yielded four quaternary mixed Te/S compounds, with the respective chalcogen atoms residing in different crystallographic sites. Two-dimensional thiotellurite compounds (Ag2TeS3) 2·A2S6 (A = Rb, Cs), containing the trigonal pyramidal [TeS 3]2- unit, were synthesized and characterized. These structures are composed of layers of neutral [Ag2TeS3] alternating with charge-balanced salt layers containing the polysulfide chain [S6]2- and alkali metal ions. Using mixed Te/S polychalcogenide fluxes for compound discovery, we then investigated a new set of layered metal dichalcogenides, Ag2Te(MS2)3 (M = V, Nb) crystallizing in the P-62m space group. Ag2Te(MS2)3 contains layers of [Ag2Te] sandwiched between layers of [MS2] (M = V, Nb). The Ag and, more interestingly, Te atoms are linearly coordinated by S atoms in the [MS2] layers. This linear coordination of the Te atom by S atoms is unprecedented in the literature and stabilized by charge transfer within the [Ag2Te] layers. In the latter half, we report the bulk crystal growth and characterization of Tl-based chalcogenide and chalcohalide materials for hard radiation (X- and gamma-ray) detection, which requires high density, wide band gaps, and high resistivity. Lattice hybridization was applied to identify materials with optimal properties for hard radiation detection, resulting in the chalcohalide compound Tl6SI4. Tl6SI4 exhibits low effective mass of carriers, high resistivity, optimal band gap, and large hardness values. The figure of merit mutau products, (mutau) e = 2.1 x 10-3 cm2V-1 and (mutau)h = 2.3 x 10-5 cm2V -1, are comparable to state-of-the-art commercially used materials. Furthermore, high resolution detection of Ag X-rays by Tl6SI 4 was seen at 22 keV (2.6%). Dimensional reduction was used to identify Tl-based chalcogenide materials Tl2MS3 (M = Ge, Sn). Tl2MS3 show great potential for use as hard radiation detectors, with preliminary mutau values on the order of ˜10-4 cm2V -1. Tl2SnS3 shows effective room temperature detection of Ag X-rays with low leakage current in the || direction; this anisotropy indicates that optimization of orientation should increase detector performance. Improvements in crystal growth and processing of these Tl-based compounds should yield detector materials that rival or outperform currently used devices.

  9. Influence of variable tungsten valency on optical transmittance and radiation hardness of lead tungstate (PWO) scintillation crystals

    Microsoft Academic Search

    S. Burachas; S. Beloglovski; I. Makova; Y. Saveliev; M. Ippolitov; V. Manko; S. Nikulin; A. Nyanin; A. Vassiliev; A. Apanasenko; G. Tamulaitis

    2003-01-01

    A new approach to interpret the radiation hardness of PbWO4 (PWO) scintillators is developed by revealing importance of the inclusions of tungsten oxides WO3?x with variable valency. It is demonstrated that the influence of the ionizing radiation on PWO is, in many aspects, similar to the effect of the high-temperature annealing in oxygenless ambient. In both cases, a valency change

  10. Photodiode radiation hardness, lyman-alpha emitting galaxies and photon detection in liquid argon neutrino detectors

    NASA Astrophysics Data System (ADS)

    Baptista, Brian

    My dissertation is comprised of three projects: 1) studies of Lyman-alpha Emitting galaxies (LAEs), 2) radiation hardness studies of InGaAs photodiodes (PDs), and 3) scintillation photon detection in liquid argon (LAr) neutrino detectors. I began work on the project that has now become WFIRST, developing a science case that would use WFIRST after launch for the observation of LAEs. The radiation hardness of PDs was as an effort to support the WFIRST calibration team. When WFIRST was significantly delayed, I joined an R&D effort that applied my skills to work on photon detection in LAr neutrino detectors. I report results on a broadband selection method developed to detect high equivalent width (EW) LAEs. Using photometry from the CFHT-Legacy Survey Deep 2 and 3 fields, I have spectroscopically confirmed 63 z=2.5-3.5 LAEs using the WIYN/Hydra spectrograph. Using UV continuum-fitting techniques I computed properties such as EWs, internal reddening and star formation rates. 62 of my LAEs show evidence to be normal dust-free LAEs. Second, I present an investigation into the effects of ionizing proton radiation on commercial off-the-shelf InGaAs PDs. I developed a monochromator-based test apparatus that utilized NIST-calibrated reference PDs. I tested the PDs for changes to their dark current, relative responsivity as a function of wavelength, and absolute responsivity. I irradiated the test PDs using 30, 52, and 98 MeV protons at the IU Cyclotron Facility. I found the InGaAs PDs showed increased dark current as the fluence increased with no evidence of broadband response degradation at the fluences expected at an L2 orbit and a 10-year mission lifetime. Finally, I detail my efforts on technology development of both optical detector technologies and waveshifting light guide construction for LAr vacuum UV scintillation light. Cryogenic neutrino detectors use photon detection for both accelerator based science and for SNe neutrino detection and proton decay. I have developed waveshifter doped cast acrylic light guides that convert scintillation light and guide the waveshifted light to SiPMs detectors.

  11. Single-Event Gate Rupture in Power MOSFETs: A New Radiation Hardness Assurance Approach

    NASA Technical Reports Server (NTRS)

    Lauenstein, Jean-Marie

    2011-01-01

    Almost every space mission uses vertical power metal-semiconductor-oxide field-effect transistors (MOSFETs) in its power-supply circuitry. These devices can fail catastrophically due to single-event gate rupture (SEGR) when exposed to energetic heavy ions. To reduce SEGR failure risk, the off-state operating voltages of the devices are derated based upon radiation tests at heavy-ion accelerator facilities. Testing is very expensive. Even so, data from these tests provide only a limited guide to on-orbit performance. In this work, a device simulation-based method is developed to measure the response to strikes from heavy ions unavailable at accelerator facilities but posing potential risk on orbit. This work is the first to show that the present derating factor, which was established from non-radiation reliability concerns, is appropriate to reduce on-orbit SEGR failure risk when applied to data acquired from ions with appropriate penetration range. A second important outcome of this study is the demonstration of the capability and usefulness of this simulation technique for augmenting SEGR data from accelerator beam facilities. The mechanisms of SEGR are two-fold: the gate oxide is weakened by the passage of the ion through it, and the charge ionized along the ion track in the silicon transiently increases the oxide electric field. Most hardness assurance methodologies consider the latter mechanism only. This work demonstrates through experiment and simulation that the gate oxide response should not be neglected. In addition, the premise that the temporary weakening of the oxide due to the ion interaction with it, as opposed to due to the transient oxide field generated from within the silicon, is validated. Based upon these findings, a new approach to radiation hardness assurance for SEGR in power MOSFETs is defined to reduce SEGR risk in space flight projects. Finally, the potential impact of accumulated dose over the course of a space mission on SEGR susceptibility is explored. SEGR evaluation of gamma-irradiated power MOSFETs suggests a non-significant SEGR susceptibility enhancement due to accumulated dose from gamma rays. During SEGR testing, an unexpected enhanced dose effect from heavy-ion irradiation was detected. We demonstrate that this effect could be due to direct ionization by two or more ions at the same channel location. The probability on-orbit for such an occurrence is near-zero given the low heavy-ion fluence over a typical mission lifetime, and did not affect SEGR susceptibility. The results of this work can be used to bound the risk of SEGR in power MOSFETs considered for insertion into spacecraft and instruments.

  12. Effects of high pressure thermal treatments in oxygen and helium atmospheres on amorphous silicon dioxide and its radiation hardness

    Microsoft Academic Search

    L. Nuccio; S. Agnello; R. Boscaino; B. Brichard

    2009-01-01

    The effects of thermal treatments at ?400°C in oxygen or helium atmospheres at ?180bar on the radiation hardness of amorphous SiO2 are studied. The generation efficiency of several point defects under ? irradiation is compared to that of the untreated material. All the effects on point defects generation here observed can be explained in terms of changes in the precursor

  13. The effect of oxygen impurities on radiation hardness of FZ silicon detectors for HEP after neutron, proton and gamma irradiation

    Microsoft Academic Search

    B. Dezillie; Z. Li; V. Eremin; W. Chen; L. J. Zhao

    2000-01-01

    The radiation hardness for fast neutrons, high energy protons and 60Co gamma rays of planar detectors processed from highly oxygenated silicon detectors obtained by using high temperature (1200°C), long time (> 200 hours) oxidation technology, are compared with standard silicon detectors. For fast neutron irradiation it is found that there is no advantage of using highly oxygenated silicon FZ detectors

  14. The effect of oxygen impurities on radiation hardness of FZ silicon detectors for HEP after neutron, proton and gamma irradiation

    Microsoft Academic Search

    B. Dezillie; Z. Li; V. Eremin; W. Chen; L. J. Zhao

    1999-01-01

    Radiation hardness for fast neutrons, high energy protons and 60Co gamma rays of planar detectors processed from highly oxygenated silicon detectors obtained by using the high temperature (1200°C), long time (>200 hours) oxidation technology, are compared with standard silicon detectors. For fast neutron irradiation it is found that there is no advantage of using highly oxygenated silicon FZ detectors as

  15. Radiation hardness of silicon detectors manufactured on epitaxial material and FZ bulk enriched with oxygen, carbon, tin and platinum

    Microsoft Academic Search

    A. Ruzin; G. Casse; M. Glaser; F. Lemeilleur; R. Talamonti; S. Watts; A. Zanet

    1999-01-01

    Recent results on the radiation hardness of silicon detectors fabricated on epitaxial and float zone bulk silicon enriched by various impurities, such as carbon, oxygen, tin and platinum are reported. A new methodology of measurements of electrical properties of the devices has been utilized in the experiment. It has been shown that in the case of irradiation by protons, oxygen

  16. Applications of Robust, Radiation Hard AlGaN Optoelectronic Devices in Space Exploration and High Energy Density Physics

    SciTech Connect

    Sun, K.

    2011-05-04

    This slide show presents: space exploration applications; high energy density physics applications; UV LED and photodiode radiation hardness; UV LED and photodiode space qualification; UV LED AC charge management; and UV LED satellite payload instruments. A UV LED satellite will be launched 2nd half 2012.

  17. Experimental methods for the assessment of tribological hard contacts at the device, component, and surface scales

    Microsoft Academic Search

    David Andrew Nickel

    1999-01-01

    Measurement techniques are applied to tribocomponents at three size scales. Device-level parameters are assessed in a displacement-controlled axial bearing test rig. Component-level testing is performed using a miniature radio telemeter embedded in a bearing roller. Contact pressure and temperature are measured with thin-film contact sensors fabricated on steel and glass disks and loaded in an optical EHL (elastohydrodynamic lubrication) test

  18. Radiation hardness studies of n + -in-n planar pixel sensors for the ATLAS upgrades

    NASA Astrophysics Data System (ADS)

    Altenheiner, S.; Goessling, C.; Jentzsch, J.; Klingenberg, R.; Muenstermann, D.; Rummler, A.; Troska, G.; Wittig, T.

    2011-12-01

    The ATLAS experiment at the LHC is planning upgrades of its pixel detector to cope with the luminosity increase foreseen in the coming years within the transition from LHC to Super-LHC (SLHC/HL-LHC). Associated with the increase in instantaneous luminosity is a rise of the target integrated luminosity from 730 to about 3000 fb -1 which directly translates into significantly higher radiation damage. These upgrades consist of the installation of a 4th pixel layer, the insertable b-layer IBL, with a mean sensor radius of only 32 mm from the beam axis, before 2016/17. In addition, the complete pixel detector will be exchanged before 2020/21. Being very close to the beam, the radiation damage of the IBL sensors might be as high as 5×1015 neq cm-2 at their end-of-life. The total fluence of the innermost pixel layer after the SLHC upgrade might even reach 2×1016 neq cm-2. To investigate the radiation hardness and suitability of the current ATLAS pixel sensors for these fluences, n +-in-n silicon pixel sensors from the ATLAS Pixel production have been irradiated by reactor neutrons to the IBL design fluence and been tested with pions at the SPS and with electrons from a 90Sr source in the laboratory. The collected charge after IBL fluences was found to exceed 10 000 electrons per MIP at 1 kV of bias voltage which is in agreement with data collected with strip sensors. After SLHC fluences, still reliable operation of the devices could be observed with a collected charge of more than 5000 electrons per MIP.

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

    SciTech Connect

    Sun, K. X.

    2011-05-31

    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.

  20. Method of using infrared radiation for assembling a first component with a second component

    DOEpatents

    Sikka, Vinod K. (Oak Ridge, TN); Whitson, Barry G. (Corryton, TN); Blue, Craig A. (Knoxville, TN)

    1999-01-01

    A method of assembling a first component for assembly with a second component involves a heating device which includes an enclosure having a cavity for inserting a first component. An array of infrared energy generators is disposed within the enclosure. At least a portion of the first component is inserted into the cavity, exposed to infrared energy and thereby heated to a temperature wherein the portion of the first component is sufficiently softened and/or expanded for assembly with a second component.

  1. Generation of radicals in hard biological tissues under the action of laser radiation

    NASA Astrophysics Data System (ADS)

    Sviridov, Alexander P.; Bagratashvili, Victor N.; Sobol, Emil N.; Omelchenko, Alexander I.; Lunina, Elena V.; Zhitnev, Yurii N.; Markaryan, Galina L.; Lunin, Valerii V.

    2002-07-01

    The formation of radicals upon UV and IR laser irradiation of some biological tissues and their components was studied by the EPR technique. The radical decay kinetics in body tissue specimens after their irradiation with UV light were described by various models. By the spin trapping technique, it was shown that radicals were not produced during IR laser irradiation of cartilaginous tissue. A change in optical absorption spectra and the dynamics of optical density of cartilaginous tissue, fish scale, and a collagen film under exposure to laser radiation in an air, oxygen, and nitrogen atmosphere was studied.

  2. Qualitative Histological Evaluation of Hard and Soft Tissue Components of Human Permanent Teeth Using Various Decalcifying Agents - A Comparative Study

    PubMed Central

    Jawanda, Manveen Kaur; SM, Manjunath; Bharti, Achla

    2014-01-01

    Introduction: Decalcification is the commonly employed technique in histopathology laboratories as a part of calcified tissue preparation for the microscopic examination. Chemical agents are most commonly used for routine decalcification procedures, though some agents adversely affect the tissue integrity and staining properties. Aim: To compare the efficacy of various decalcifying agents by histological evaluation of hard and soft tissue components of teeth. Materials and Methods: The five decalcifying agents namely 10% Nitric acid (HNO3), 10% Formal nitric acid (FNA), 10 % Formic acid (FA), 8% Potassium formate (KF) + 8% Formic acid (FA) and Neutral Ethylenediamenetetracetic acid (EDTA) were used to decalcify 60 human permanent teeth. The specimens were subjected to routine processing, sectioning and staining with hematoxylin and eosin. The stained sections were observed under light microscope by three independent observers and grading was done. Statistical Analysis: Paired sample t-test was done for inter-observer variation. One-way-ANOVA and Post-hoc test was applied to compare the effects of different decalcifying agents. Results: Considering preservation and staining characteristics of both hard and soft tissues, superior results were obtained with 10% HNO3 followed by 10% FNA and EDTA which was according to the respective mean values obtained. But statistically significant difference was shown only with 10% FA & 8% KF + 8% FA. Conclusion: HNO3 was showing the most efficient result as it balances both tissue integrity and time factor suggesting that it can be used as a stable decalcifying agent for routine histopathological diagnosis. PMID:25386527

  3. Radiation hardening of components and systems for nuclear rocket vehicle applications

    NASA Technical Reports Server (NTRS)

    Greenhow, W. A.; Cheever, P. R.

    1972-01-01

    The results of the analysis of the S-2 and S-4B components, although incomplete, indicate that many Saturn 5 components and subsystems, e.g., pumps, valves, etc., can be radiation hardened to meet NRV requirements by material substitution and minor design modifications. Results of these analyses include (1) recommended radiation tolerance limits for over 100 material applications; (2) design data which describes the components of each system; (3) presentation of radiation hardening examples of systems; and (4) designing radiation effects tests to supply data for selecting materials.

  4. Radiation Hard Bandpass Filters for Mid- to Far-IR Planetary Instruments

    NASA Technical Reports Server (NTRS)

    Brown, Ari D.; Aslam, Shahid; Chervenack, James A.; Huang, Wei-Chung; Merrell, Willie C.; Quijada, Manuel; Steptoe-Jackson, Rosalind; Wollack, Edward J.

    2012-01-01

    We present a novel method to fabricate compact metal mesh bandpass filters for use in mid- to far-infrared planetary instruments operating in the 20-600 micron wavelength spectral regime. Our target applications include thermal mapping instruments on ESA's JUICE as well as on a de-scoped JEO. These filters are novel because they are compact, customizable, free-standing copper mesh resonant bandpass filters with micromachined silicon support frames. The filters are well suited for thermal mapping mission to the outer planets and their moons because the filter material is radiation hard. Furthermore, the silicon support frame allows for effective hybridization with sensors made on silicon substrates. Using a Fourier Transform Spectrometer, we have demonstrated high transmittance within the passband as well as good out-of-band rejection [1]. In addition, we have developed a unique method of filter stacking in order to increase the bandwidth and sharpen the roll-off of the filters. This method allows one to reliably control the spacing between filters to within 2 microns. Furthermore, our method allows for reliable control over the relative position and orienta-tion between the shared faces of the filters.

  5. Tests of Radiation-Hard Silicon Microstrip Sensors for CMS in S-LHC

    SciTech Connect

    Luukka, Panja; Maenpaa, Teppo; Tuovinen, Esa; /Helsinki Institute of Physics; Spiegel, Lenny; /Fermilab; Flight, Robert; /Rochester U.

    2011-02-21

    The tests are to study the performance of various silicon microstrip sensors that are sufficiently radiation-hard to be considered as candidates for the CMS outer (R > 25cm) tracker in the second phase of the currently envisioned S-LHC upgrade. The main goal of the beam test is to test Float Zone (FZ) and Magnetic Czochralski (MCz) silicon sensors that have been procured from Hamamatsu by the CMS collaboration as possible replacements for the CMS outer tracker for phase 2 operations. The detectors under test (DUT) will be isntalled in a cold box that contains 10 slots for modules based on CMS Tracker hybrids. Slots 1-4 and 7-10 are occupied by reference planes and slots 5 and 6 are reserved for DUTs. The box is cooled by Peltier elements in thermal contact with the top and bottom aluminum baseplates and is typically operated at around -25 C. A PCI based version of the CMS DAQ is used to read out the 10 slots based on triggers provided by beam scintillation counters. Given the low rate of beam particles the hybrid APVs will be operated in Peak mode, which maximizes the signal-to-noise performance of the readout chips. The internal clock operates at the LHC frequency of 40 MHz.

  6. Pixel frontend electronics in a radiation hard technology for hybrid and monolithic applications

    SciTech Connect

    Pengg, F. [CERN, Geneva (Switzerland)] [CERN, Geneva (Switzerland); [Johannes Kepler Univ. Linz (Austria); Campbell, M.; Heijne, E.H.M.; Snoeys, W. [CERN, Geneva (Switzerland)] [CERN, Geneva (Switzerland)

    1996-06-01

    Pixel detector readout cells have been designed in the radiation hard DMILL technology and their characteristics evaluated before and after irradiation to 14Mrad. The test chip consists of two blocks of six readout cells each. Two different charge amplifiers are implemented, one of them using a capacitive feedback loop, the other the fast signal charge transfer to a high impedance integrating node. The measured equivalent noise charge is 110e{sup {minus}}r.m.s. before and 150e{sup {minus}}r.m.s. after irradiation. With a discriminator threshold set to 5000e{sup {minus}}, which reduces for the same bias setting to 400e{sup {minus}} after irradiation, the threshold variation is 300e{sup {minus}}r.m.s. and 250e{sup {minus}}r.m.s. respectively. The time walk is 40ns before and after irradiation. The use of this SOI technology for monolithic integration of electronics and detector in one substrate is under investigation.

  7. Radiation Evaluation of an Advanced 64Mb 3.3V DRAM and Insights into the Effects of Scaling on Radiation Hardness

    NASA Technical Reports Server (NTRS)

    Shaw, D. C.; Swift, G. M.; Johnston, A. H.

    1995-01-01

    In this paper, total ionizing dose radiation evaluations of the Micron 64 Mb 3.3 V, fast page mode DRAM and the IBM LUNA-ES 16 Mb DRAM are presented. The effects of scaling on total ionizing dose radiation hardness are studied utilizing test structures and a series of 16 Mb DRAMs with different feature sizes from the same manufacturing line. General agreement was found between the threshold voltage shifts of 16 Mb DRAM test structures and the threshold voltage measured on complete circuits using retention time measurements. Retention time measurement data from early radiation doses are shown that allow internal failure modes to be distinguished.

  8. Hard coatings deposited by various thermal processes: Effect on fatigue resistance of typical alloys for helicopter components

    SciTech Connect

    Buffoli, A.; Pesetti, M. [Agusta S.p.A., Samarate (Italy)

    1995-12-31

    Hard coatings are more and more widely applied on helicopter components to repair worn surfaces and to improve wear and fretting resistance. The potential negative effect of these coatings on fatigue life shall be known for the correct design of the component. Different tungsten carbide based, nickel and chromium oxide coatings were applied by Plasma Spray, Detonation Gun, Super Detonation Gun, Jet Coat, CDS and HVOF on specimens made form the following materials: AISI 9310 and AISI 4340 alloy steels and Ti6Al4V titanium alloy. The rotating bending (R = {minus}1) fatigue life of the coated specimens was evaluated and compared with that of the uncoated specimens. Except for the Super D-Gun process, a general reduction in fatigue life is noted on coated steel specimens, varying from {minus}9 to {minus}47%. On coated titanium specimens the reduction in fatigue life is more sensitive, from {minus}15 to {minus}63%, and the beneficial effect of shot-peening is demonstrated.

  9. Radiation induced loss properties and hardness enhancement technique for ErYb doped fibers for avionic applications

    NASA Astrophysics Data System (ADS)

    Yeniay, A.; Gao, R. F.

    2013-03-01

    We present radiation reliability properties and their enhancement of ErYb doped optical fibers in terms of induced loss and lifetime prediction via master curve analysis method. In this study, we are primarily concerned with the effects of ionizing radiation on the performance of double cladded ErYb doped optical fibers in an accelerated low dose ?-radiation environment (i.e. <120 rad/h rate) for high power optical amplifiers to be used in satellite communication systems. We demonstrate a novel method that utilizes pre-radiation exposure and thermal annealing, for enhancing radiation hardness of the fibers with respect to induced optical loss and lifetime prediction. Based on this method, we are able to modify radiation induced loss-rate properties of the fiber with an initial loss penalty, realizing overall loss-budget improvement for relatively long-term deployment (i.e. >5 years). In a direct comparison to non-hardened ErYb doped fibers, we demonstrate approximately 0.16 dB/m of radiation induced loss improvement including an initial loss penalty of 0.14 dB for radiation-hardened fibers over a 10-year duration in a natural low dose (i.e. <0.3 rad/h) radiation environment, i.e. low earth orbit.

  10. Radiation hardness evaluation of a 130 nm SiGe BiCMOS technology for high energy physics applications

    NASA Astrophysics Data System (ADS)

    Díez, S.; Clark, T.; Grillo, A. A.; Kononenko, W.; Martinez-McKinney, F.; Newcomer, F. M.; Norgren, M.; Rescia, S.; Spencer, E.; Spieler, H.; Ullán, M.; Wilder, M.

    2013-10-01

    Final results for a comprehensive radiation hardness evaluation of a high performance, low cost, 130 nm SiGe BiCMOS technology are presented. After a survey of several available SiGe technologies, one was chosen in terms of performance, power consumption, radiation hardness, and cost and it is presented as a suitable technology for the future upgrades of the ATLAS detector of the High Luminosity LHC. Bipolar devices of different sizes and geometries have been evaluated, along with a prototype Front-End readout ASIC designed for binary readout of silicon microstrip detectors. Gamma, neutron and proton irradiations have been performed up to the expected doses and fluences of the experiment.

  11. Radiation hardness of Czochralski silicon, Float Zone silicon and oxygenated Float Zone silicon studied by low energy protons

    Microsoft Academic Search

    J. Härkönen; E. Tuovinen; P. Luukka; E. Tuominen; K. Lassila-Perini; P. Mehtälä; S. Nummela; J. Nysten; A. Zibellini; Z. Li; E. Fretwurst; G. Lindstroem; J. Stahl; F. Hönniger; V. Eremin; A. Ivanov; E. Verbitskaya; P. Heikkilä; V. Ovchinnikov; M. Yli-Koski; P. Laitinen; A. Pirojenko; I. Riihimäki; A. Virtanen

    2004-01-01

    We processed pin-diodes on Czochralski silicon (Cz-Si), standard Float Zone silicon (Fz-Si) and oxygenated Fz-Si. The diodes were irradiated with 10, 20, and 30MeV protons. Depletion voltages and leakage currents were measured as a function of the irradiation dose. Additionally, the samples were characterized by TCT and DLTS methods. The high-resistivity Cz-Si was found to be more radiation hard than

  12. Improvement of optical properties and radiation hardness of NaBi(WO4)2 Cherenkov crystals

    Microsoft Academic Search

    B. I. Zadneprovski; V. A. Nefedov; E. V. Polyansky; E. G. Devitsin; V. A. Kozlov; S. Y. Potashov; A. R. Terkulov

    2002-01-01

    On the basis of the data on melt evaporation while growing NaBi(WO4)2 Cherenkov crystals, the formation of nonstoichiometry and most probable types of dot defects of the crystals have been considered. The influence of melt nonstoichiometry and doping with Sc on optical transmission and radiation hardness of the crystals has been experimentally investigated. The surplus of WO3 has been established

  13. Radiation hardness of Ga0.5In0.5 P/GaAs tandem solar cells

    NASA Technical Reports Server (NTRS)

    Kurtz, Sarah R.; Olson, J. M.; Bertness, K. A.; Friedman, D. J.; Kibbler, A.; Cavicchi, B. T.; Krut, D. D.

    1991-01-01

    The radiation hardness of a two-junction monolithic Ga sub 0.5 In sub 0.5 P/GaAs cell with tunnel junction interconnect was investigated. Related single junction cells were also studied to identify the origins of the radiation losses. The optimal design of the cell is discussed. The air mass efficiency of an optimized tandem cell after irradiation with 10(exp 15) cm (-2) 1 MeV electrons is estimated to be 20 percent using currently available technology.

  14. Radiation Hard Hybrid Pixel Detectors, and a bb¯ Cross-Section Measurement at the CMS Experiment

    NASA Astrophysics Data System (ADS)

    Sibille, Jennifer A.

    Measurements of heavy flavor quark production at hadron colliders provide a good test of the perturbative quantum chromodynamics (pQCD) theory. It is also essential to have a good understanding of the heavy quark production in the search for new physics. Heavy quarks contribute to backgrounds and signals in measurements of higher mass objects, such as the Higgs boson. A key component to each of these measurements is good vertex resolution. In order to ensure reliable operation of the pixel detector, as well as confidence in the results of analyses utilizing it, it is important to study the effects of the radiation on the detector. In the first part of this dissertation, the design of the CMS silicon pixel detector is described. Emphasis is placed on the effects of the high radiation environment on the detector operation. Measurements of the charge collection efficiency, interpixel capacitance, and other properties of the pixel sensors as a function of the radiation damage are presented. In the second part, a measurement of the inclusive bb¯ production cross section using the b ? muD 0X, D0 ? Kpi decay chain with data from the CMS experiment at the LHC is presented. The data were recorded with the CMS experiment at the Large Hadron Collider (CERN) in 2010 using unprescaled single muon triggers corresponding to a total luminosity of 25 pb-1. The differential cross section is measured for pD0mT > 6 GeV/c and |eta| < 2.4 corresponding to a total cross section of 4.36+/-0.54(stat.) +0.28-0.25 (sys.)+/-0.17( B )+/-0.23( L ) mu b.

  15. Design of high-efficiency, radiation-hard, GaInP/GaAs solar cells

    NASA Astrophysics Data System (ADS)

    Kurtz, Sarah R.; Bertness, K. A.; Kibbler, A. E.; Kramer, C.; Olson, J. M.

    1994-09-01

    In recently years, Ga(0.5)In((0.5)P/GaAs cells have drawn increased attention both because of their high efficiencies and because they are well suited for space applications. They can be grown and processed as two-junction devices with roughly twice the voltage and half the current of GaAs cells. They have low temperature coefficients, and have good potential for radiation hardness. We have previously reported the effects of electron irradiation on test cells which were not optimally designed for space. From those results we estimated that an optimally designed cell could achieve 20 percent after irradiation with 10(exp 15) cm(exp -2) 1 MeV electrons. Modeling studies predicted that slightly higher efficiencies may be achievable. Record efficiencies for EOL performance of other types of cells are significantly lower. Even the best Si and InP cells have BOL efficiencies lower than the EOL efficiency we report here. Good GaAs cells have an EOL efficiency of 16 percent. The InP/Ga(0.5)In(0.5)As two-junction, two-terminal device has a BOL efficiency as high as 22.2 percent, but radiation results for these cells were limited. In this study we use the previous modeling and irradiation results to design a set of Ga(0.5)In(0.5)P/GaAs cells that will demonstrate the importance of the design parameters and result in high-efficiency devices. We report record AMO efficiencies: a BOL efficiency of 25.7 percent for a device optimized for BOL performance and two of different designs with EOL efficiencies of 19.6 percent (at 10(exp 15) cm(exp -2) 1MeV electrons). We vary the bottom-cell base doping and the top-cell thickness to show the effects of these two important design parameters. We get an unexpected result indicating that the dopant added to the bottom-cell base also increases the degradation of the top cell.

  16. Design of high-efficiency, radiation-hard, GaInP/GaAs solar cells

    NASA Technical Reports Server (NTRS)

    Kurtz, Sarah R.; Bertness, K. A.; Kibbler, A. E.; Kramer, C.; Olson, J. M.

    1994-01-01

    In recently years, Ga(0.5)In((0.5)P/GaAs cells have drawn increased attention both because of their high efficiencies and because they are well suited for space applications. They can be grown and processed as two-junction devices with roughly twice the voltage and half the current of GaAs cells. They have low temperature coefficients, and have good potential for radiation hardness. We have previously reported the effects of electron irradiation on test cells which were not optimally designed for space. From those results we estimated that an optimally designed cell could achieve 20 percent after irradiation with 10(exp 15) cm(exp -2) 1 MeV electrons. Modeling studies predicted that slightly higher efficiencies may be achievable. Record efficiencies for EOL performance of other types of cells are significantly lower. Even the best Si and InP cells have BOL efficiencies lower than the EOL efficiency we report here. Good GaAs cells have an EOL efficiency of 16 percent. The InP/Ga(0.5)In(0.5)As two-junction, two-terminal device has a BOL efficiency as high as 22.2 percent, but radiation results for these cells were limited. In this study we use the previous modeling and irradiation results to design a set of Ga(0.5)In(0.5)P/GaAs cells that will demonstrate the importance of the design parameters and result in high-efficiency devices. We report record AMO efficiencies: a BOL efficiency of 25.7 percent for a device optimized for BOL performance and two of different designs with EOL efficiencies of 19.6 percent (at 10(exp 15) cm(exp -2) 1MeV electrons). We vary the bottom-cell base doping and the top-cell thickness to show the effects of these two important design parameters. We get an unexpected result indicating that the dopant added to the bottom-cell base also increases the degradation of the top cell.

  17. The impact of microwave stray radiation to in-vessel diagnostic components

    SciTech Connect

    Hirsch, M.; Laqua, H. P.; Hathiramani, D.; Baldzuhn, J.; Biedermann, C.; Cardella, A.; Erckmann, V.; König, R.; Köppen, M.; Zhang, D. [Max-Planck-Institut für Plasmaphysik, Teilinstitut Greifswald, EURATOM Association, D-17489 Greifswald (Germany); Oosterbeek, J.; Brand, H. von der; Parquay, S. [Technische Universiteit Eindhoven, department Technische Natuurkunde, working group for Plasma Physics and Radiation Technology, Den Doelch 2, 5612 AZ Eindhoven (Netherlands); Jimenez, R. [Centro de Investigationes Energeticas, Medioambientales y Technológicas, Association EURATOM/CIEMAT, Avenida Complutense 22, Madrid 28040 (Spain); Collaboration: W7-X Teasm

    2014-08-21

    Microwave stray radiation resulting from unabsorbed multiple reflected ECRH / ECCD beams may cause severe heating of microwave absorbing in-vessel components such as gaskets, bellows, windows, ceramics and cable insulations. In view of long-pulse operation of WENDELSTEIN-7X the MIcrowave STray RAdiation Launch facility, MISTRAL, allows to test in-vessel components in the environment of isotropic 140 GHz microwave radiation at power load of up to 50 kW/m{sup 2} over 30 min. The results show that both, sufficient microwave shielding measures and cooling of all components are mandatory. If shielding/cooling measures of in-vessel diagnostic components are not efficient enough, the level of stray radiation may be (locally) reduced by dedicated absorbing ceramic coatings on cooled structures.

  18. The impact of microwave stray radiation to in-vessel diagnostic components

    NASA Astrophysics Data System (ADS)

    Hirsch, M.; Laqua, H. P.; Hathiramani, D.; Oosterbeek, J.; Baldzuhn, J.; Biedermann, C.; v d Brand, H.; Cardella, A.; Erckmann, V.; Jimenez, R.; König, R.; Köppen, M.; Parquay, S.; Zhang, D.; W7-X Team

    2014-08-01

    Microwave stray radiation resulting from unabsorbed multiple reflected ECRH / ECCD beams may cause severe heating of microwave absorbing in-vessel components such as gaskets, bellows, windows, ceramics and cable insulations. In view of long-pulse operation of WENDELSTEIN-7X the MIcrowave STray RAdiation Launch facility, MISTRAL, allows to test in-vessel components in the environment of isotropic 140 GHz microwave radiation at power load of up to 50 kW/m2 over 30 min. The results show that both, sufficient microwave shielding measures and cooling of all components are mandatory. If shielding/cooling measures of in-vessel diagnostic components are not efficient enough, the level of stray radiation may be (locally) reduced by dedicated absorbing ceramic coatings on cooled structures.

  19. Space Radiation Shielding Studies for Astronaut and Electronic Component Risk Assessment

    NASA Technical Reports Server (NTRS)

    Fuchs, Jordan Robert

    2010-01-01

    The dosimetry component of the Center for Radiation Engineering and Science for Space Exploration (CRESSE) will design, develop and characterize the response of a suite of radiation detectors and supporting instrumentation and electronics with three primary goals that will: (1) Use established space radiation detection systems to characterize the primary and secondary radiation fields existing in the experimental test-bed zones during exposures at particle accelerator facilities. (2) Characterize the responses of newly developed space radiation detection systems in the experimental test-bed zones during exposures at particle accelerator facilities, and (3) Provide CRESSE collaborators with detailed dosimetry information in experimental test-bed zones.

  20. On the Barometer Effect on the Hard Component of the Cosmic Radiation

    Microsoft Academic Search

    H. Trefall

    1955-01-01

    The interpretation of the observed partial correlation between the meson intensity at sea level and the barometric pressure, the other independent variables of the regression equation being the height of the 100 mb level and the stratospheric temperature, is discussed. It is shown that even though the decay effect due to changes in the height of the meson-producing layer is

  1. A National Radiation Oncology Medical Student Clerkship Survey: Didactic Curricular Components Increase Confidence in Clinical Competency

    SciTech Connect

    Jagadeesan, Vikrant S. [Department of Radiation and Cellular Oncology, Pritzker School of Medicine, University of Chicago, Chicago, Illinois (United States); Raleigh, David R. [Department of Radiation Oncology, School of Medicine, University of California–San Francisco, San Francisco, California (United States); Koshy, Matthew; Howard, Andrew R.; Chmura, Steven J. [Department of Radiation and Cellular Oncology, Pritzker School of Medicine, University of Chicago, Chicago, Illinois (United States); Golden, Daniel W., E-mail: dgolden@radonc.uchicago.edu [Department of Radiation and Cellular Oncology, Pritzker School of Medicine, University of Chicago, Chicago, Illinois (United States)

    2014-01-01

    Purpose: Students applying to radiation oncology residency programs complete 1 or more radiation oncology clerkships. This study assesses student experiences and perspectives during radiation oncology clerkships. The impact of didactic components and number of clerkship experiences in relation to confidence in clinical competency and preparation to function as a first-year radiation oncology resident are evaluated. Methods and Materials: An anonymous, Internet-based survey was sent via direct e-mail to all applicants to a single radiation oncology residency program during the 2012-2013 academic year. The survey was composed of 3 main sections including questions regarding baseline demographic information and prior radiation oncology experience, rotation experiences, and ideal clerkship curriculum content. Results: The survey response rate was 37% (70 of 188). Respondents reported 191 unique clerkship experiences. Of the respondents, 27% (19 of 70) completed at least 1 clerkship with a didactic component geared towards their level of training. Completing a clerkship with a didactic component was significantly associated with a respondent's confidence to function as a first-year radiation oncology resident (Wilcoxon rank–sum P=.03). However, the total number of clerkships completed did not correlate with confidence to pursue radiation oncology as a specialty (Spearman ? P=.48) or confidence to function as a first year resident (Spearman ? P=.43). Conclusions: Based on responses to this survey, rotating students perceive that the majority of radiation oncology clerkships do not have formal didactic curricula. Survey respondents who completed a clerkship with a didactic curriculum reported feeling more prepared to function as a radiation oncology resident. However, completing an increasing number of clerkships does not appear to improve confidence in the decision to pursue radiation oncology as a career or to function as a radiation oncology resident. These results support further development of structured didactic curricula for the radiation oncology clerkship.

  2. Spaceflight Ka-Band High-Rate Radiation-Hard Modulator

    NASA Technical Reports Server (NTRS)

    Jaso, Jeffery M.

    2011-01-01

    A document discusses the creation of a Ka-band modulator developed specifically for the NASA/GSFC Solar Dynamics Observatory (SDO). This flight design consists of a high-bandwidth, Quadriphase Shift Keying (QPSK) vector modulator with radiation-hardened, high-rate driver circuitry that receives I and Q channel data. The radiationhard design enables SDO fs Ka-band communications downlink system to transmit 130 Mbps (300 Msps after data encoding) of science instrument data to the ground system continuously throughout the mission fs minimum life of five years. The low error vector magnitude (EVM) of the modulator lowers the implementation loss of the transmitter in which it is used, thereby increasing the overall communication system link margin. The modulator comprises a component within the SDO transmitter, and meets the following specifications over a 0 to 40 C operational temperature range: QPSK/OQPSK modulator, 300-Msps symbol rate, 26.5-GHz center frequency, error vector magnitude less than or equal to 10 percent rms, and compliance with the NTIA (National Telecommunications and Information Administration) spectral mask.

  3. RADECS Short Course Section 4 Radiation Hardness Assurance (RHA) for Space Systems

    NASA Technical Reports Server (NTRS)

    Poivey, Christian

    2003-01-01

    Contents include the following: Introduction. Programmatic aspects of RHA. RHA componens: requirements and specifications; mission radiation environment; and parts selection and radiation tolerance. Analysis at the function/subsystem/system level: TID/DD; SEE. Conclusion.

  4. Radiation Hard Hybrid Pixel Detectors, and a bbbar Cross Section Measurement at the CMS Experiment

    E-print Network

    Sibille, Jennifer Ann

    2013-05-31

    is placed on the effects of the high radiation environment on the detector operation. Measurements of the charge collection efficiency, interpixel capacitance, and other properties of the pixel sensors as a function of the radiation damage are presented...

  5. Penetrating radiation impact on NIF final optic components

    SciTech Connect

    Marshall, C.D.; Speth, J.A.; DeLoach, L.D.; Payne, S.A.

    1996-10-15

    Goal of the National Ignition Facility (NIF) is to achieve thermonuclear ignition in a laboratory environment in inertial confinement fusion (ICF). This will enable NIF to service the DOE stockpile stewardship management program, inertial fusion energy goals, and advance scientific frontiers. All of these applications will make use of the extreme conditions that the facility will create in the target chamber. In the case of a prospected 20 MJ yield scenario, NIF will produce 10{sup 19} neutrons with DT fusion 14 MeV energy per neutron. There will also be high-energy x rays as well as solid, liquid, and gaseous target debris produced either directly or indirectly by the inertial confinement fusion process. A critical design issue is the protection of the final optical components as well as sophisticated target diagnostics in such a harsh environment.

  6. Hard-X-ray magnetic microscopy and local magnetization analysis using synchrotron radiation.

    PubMed

    Suzuki, Motohiro

    2014-11-01

    X-ray measurement offers several useful features that are unavailable from other microscopic means including electron-based techniques. By using X-rays, one can observe the internal parts of a thick sample. This technique basically requires no high vacuum environment such that measurements are feasible for wet specimens as well as under strong electric and magnetic fields and even at a high pressure. X-ray spectroscopy using core excitation provides element-selectivity with significant sensitivities to the chemical states and atomic magnetic moments in the matter. Synchrotron radiation sources produce a small and low-divergent X-ray beam, which can be converged to a spot with the size of a micrometer or less using X-ray focusing optics. The recent development in the focusing optics has been driving X-ray microscopy, which has already gone into the era of X-ray nanoscopy. With the use of the most sophisticated focusing devices, an X-ray beam of 7-nm size has successfully been achieved [1]. X-ray microscopy maintains above-mentioned unique features of X-ray technique, being a perfect complement to electron microscopy.In this paper, we present recent studies on magnetic microscopy and local magnetic analysis using hard X-rays. The relevant instrumentation developments are also described. The X-ray nanospectroscopy station of BL39XU at SPring-8 is equipped with a focusing optics consisting of two elliptic mirrors, and a focused X-ray beam with the size of 100 × 100 nm(2) is available [2]. Researchers can perform X-ray absorption spectroscopy: nano-XAFS (X-ray absorption fine structure) using the X-ray beam as small as 100 nm. The available X-ray energy is from 5 to 16 keV, which allows nano-XAFS study at the K edges of 3d transition metals, L edges of rare-earth elements and 5d noble metals. Another useful capability of the nanoprobe is X-ray polarization tunability, enabling magnetic circular dichroism (XMCD) spectroscopy with a sub-micrometer resolution. Scanning XMCD imaging, XMCD measurement in local areas, and element-specific magnetometry for magnetic particles/magnetic devices as small as 100 nm can be performed. Nano-XAFS application includes visualization of the chemical state in a particle catalyst [3] and phase-change memory devices [4]. For magnetic microscopic study, magnetization reversal processes of an individual magnetic CoPt dot in bit-patterned media have directly been observed [2]. Imaging of the chemical distribution and magnetic domain evolution in a Nd-Fe-B sintered magnet in demagnetization processes is presented. PMID:25359804

  7. Radiation hard sensor materials for the CMS Tracker Phase II Upgrade - Charge collection of different bulk polarities

    NASA Astrophysics Data System (ADS)

    Printz, Martin

    2014-11-01

    The upgrade of the LHC machine to deliver a significantly higher luminosity of about 5 ×1034cm-2s-1 is planned to be operational after 2022. This will simultaneously increase the radiation dose for the inner detector systems, requiring new radiation hard sensor materials for the CMS Tracker. To identify the appropriate materials which are able to withstand the radiation environment in the middle to outer layers of the CMS Tracker during the full lifetime of the high luminosity LHC, a large irradiation and measurement campaign has been conducted. Several test structures and sensors have been designed and manufactured on 18 different combinations of wafer materials, thicknesses and production technologies. The structures have been electrically characterised before and after irradiation with different fluences of neutrons and protons. This paper reports the final results on strip sensor performance considering the comparison of p-in-n technology with n-in-p type. Outcomes from signal and noise measurements before and after annealing depending on the radiation dose are discussed and the final recommendation of the CMS Tracker Collaboration for the strip sensor polarity for the Phase II Upgrade is presented.

  8. A Radiation Hard ASIC for Thermal Instrumentation on the Europa Clipper Mission

    NASA Astrophysics Data System (ADS)

    Quilligan, G.; DuMonthier, J.; Kleynor, I.; Katz, R.; Lakew, B.; Aslam, S.

    2014-02-01

    We describe one key hardware development at Goddard that is undergoing maturation for risk mitigation, a radiation hardened by design (RHBD) multi-channel digitizer (MCD) Application Specific Integrated Circuit (ASIC) for thermopile array readout.

  9. Radiation Hardness Assurance Issues Associated with COTS in JPL Flight Systems: The Challenge of Europa

    NASA Technical Reports Server (NTRS)

    Barnes, C.; Johnston, A.

    1999-01-01

    With the decreasing availability of radiation hardened electronics and the new NASA paradigm of faster, more aggressive and less expensive space missions, there has been an increasing emphasis on using high performance commercial microelectronic parts and circuits in NASA spacecraft.

  10. Comparing radiation tolerant materials and devices for ultra rad-hard tracking Mara Bruzzi

    E-print Network

    California at Santa Cruz, University of

    trapping at radiation-induced defects (with corresponding loss of charge). We will analyse these important characterizing the main electrical conductivity process in the semiconductor bulk. In silicon the characteristic

  11. A Radiation-Hard Silicon Drift Detector Array for Extraterrestrial Element Mapping

    NASA Technical Reports Server (NTRS)

    Gaskin, Jessica; Chen, Wei; De Geronimo, Gianluigi; Keister, Jeff; Li, Shaouri; Li, Zhen; Siddons, David P.; Smith, Graham

    2011-01-01

    Measurement of x-rays from the surface of objects can tell us about the chemical composition Absorption of radiation causes characteristic fluorescence from material being irradiated. By measuring the spectrum of the radiation and identifying lines in the spectrum, the emitting element (s) can be identified. This technique works for any object that has no absorbing atmosphere and significant surface irradiation : Our Moon, the icy moons of Jupiter, the moons of Mars, the planet Mercury, Asteroids and Comets

  12. In-situ minority carrier recombination lifetime measurements at radiation sources for rad-hard IR detector materials

    NASA Astrophysics Data System (ADS)

    Jenkins, Geoffrey D.; Morath, Christian P.; Cowan, Vincent M.

    2014-09-01

    Minority carrier recombination lifetime (MCRL) is a key material parameter for space-based infrared (IR) detector performance affecting both dark current and responsivity. Displacement damage due to energetic massive particles in space environments, such as protons, can significantly degrade the recombination lifetime, thereby reducing detector performance. Therefore, characterizing the change in MCRL with proton dose is of general interest from a radiation-hardness perspective. So-called "bag tests," or measurements taken prior to and following room temperature proton irradiation of the device, are often of limited value to MCRL characterization since thermal annealing effects may be present. Here, progress toward a portable MCRL measurement system employing time resolved photoluminescence (TRPL) is presented. This system can be taken to remote radiation sources where irradiation can be performed on samples followed by TRPL measurements while maintaining temperature throughout. Ideally, this system permits measurement of a lifetime radiation damage factor constant, or the change in lifetime with step-wise changes in proton dose, which is a measure of the defect introduction rate. The pulsed-laser driven TRPL measurement system is able to interrogate IR materials of interest mounted in an optical cryostat held indefinitely at a desired temperature. A system description is given and results of verification measurements are discussed for several IR detector materials.

  13. Radiation hard polyimide-coated FBG optical sensors for relative humidity monitoring in the CMS experiment at CERN

    NASA Astrophysics Data System (ADS)

    Makovec, A.; Berruti, G.; Consales, M.; Giordano, M.; Petagna, P.; Buontempo, S.; Breglio, G.; Szillasi, Z.; Beni, N.; Cusano, A.

    2014-03-01

    This work investigates the performance and the radiation hardness capability of optical thermo-hygrometers based on Fibre Bragg Gratings (FBG) for humidity monitoring in the Compact Muon Solenoid (CMS), one of the four experiments running at CERN in Geneva. A thorough campaign of characterization was performed on 80 specially produced Polyimide-coated RH FBG sensors and 80 commercial temperature FBG sensors. Sensitivity, repeatability and accuracy were studied on the whole batch, putting in evidence the limits of the sensors, but also showing that they can be used in very dry conditions. In order to extract the humidity measurements from the sensor readings, commercial temperature FBG sensors were characterized in the range of interest. Irradiation campaigns with ionizing radiation (?-rays from a Co60 source) at incremental absorbed doses (up to 210 kGy for the T sensors and up to 90 kGy for the RH sensors) were performed on sample of T and RH-Sensors. The results show that the sensitivity of the sensors is unchanged up to the level attained of the absorbed dose, while the natural wavelength peak of each sensor exhibits a radiation-induced shift (signal offset). The saturation properties of this shift are discussed.

  14. Improvement of the radiation hardness of a directly converting high resolution intra-oral X-ray imaging sensor

    NASA Astrophysics Data System (ADS)

    Spartiotis, Konstantinos; Pyyhtiä, Jouni; Schulman, Tom

    2003-11-01

    The radiation tolerance of a directly converting digital intra-oral X-ray imaging sensor reported in Spartiotis et al. [Nucl. Instr. and Meth. A 501 (2003) 594] has been tested using a typical dental X-ray beam spectrum. Radiation induced degradation in the performance of the sensor which consists of CMOS signal readout circuits bump bonded to a high resistivity silicon pixel detector was observed already before a dose (in air) of 1 krad. Both increase in the leakage current of the pixel detector manufactured by Sintef, Norway and signal leakage to ground from the gate of the pixel input MOSFETs of the readout circuit were observed and measured. The sensitive part of the CMOS circuit was identified as the protection diode of the gate of the input MOSFET. After removing the gate protection diode no signal leakage was observed up to a dose of 5 krad (air) which approximately corresponds to 125.000 typical dental X-ray exposures. The radiation hardness of the silicon pixel detector was improved by using a modified oxidation process supplied by Colibrys, Switzerland. The improved pixel detectors showed no increase in the leakage current at dental doses.

  15. Low-mass, intrinsically-hard high temperature radiator. Final report, Phase I

    SciTech Connect

    NONE

    1990-07-15

    This paper reports on the investigation of layered ceramic/metal composites in the design of low-mass hardened radiators for space heat rejection systems. The investigation is part of the Strategic Defence Initiative. This effort evaluated the use of layered composites as a material to form thin-walled, vacuum leaktight heat pipes. The heat pipes would be incorporated into a large heat pipe radiator for waste heat rejection from a space nuclear power source. Composite materials evaluations were performed on combinations of refractory metals and ceramic powders. Fabrication experiments were performed to demonstrate weldability. Two titanium/titanium diboride composite tubes were successfully fabricated into potassium heat pipes and operated at temperatures in excess of 700C. Testing and analysis for composite tubes are described in the report. The study has verified the feasibility of using layered composites for forming thin-walled, light weight heat pipe tubes for use in hardened space radiators.

  16. Fermi Observations of GRB 090510: A Short-Hard Gamma-ray Burst with an Additional, Hard Power-law Component from 10 keV TO GeV Energies

    NASA Astrophysics Data System (ADS)

    Ackermann, M.; Asano, K.; Atwood, W. B.; Axelsson, M.; Baldini, L.; Ballet, J.; Barbiellini, G.; Baring, M. G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Berenji, B.; Bhat, P. N.; Bissaldi, E.; Blandford, R. D.; Bloom, E. D.; Bonamente, E.; Borgland, A. W.; Bouvier, A.; Bregeon, J.; Brez, A.; Briggs, M. S.; Brigida, M.; Bruel, P.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caraveo, P. A.; Carrigan, S.; Casandjian, J. M.; Cecchi, C.; Çelik, Ö.; Charles, E.; Chiang, J.; Ciprini, S.; Claus, R.; Cohen-Tanugi, J.; Connaughton, V.; Conrad, J.; Dermer, C. D.; de Palma, F.; Dingus, B. L.; Silva, E. do Couto e.; Drell, P. S.; Dubois, R.; Dumora, D.; Farnier, C.; Favuzzi, C.; Fegan, S. J.; Finke, J.; Focke, W. B.; Frailis, M.; Fukazawa, Y.; Fusco, P.; Gargano, F.; Gasparrini, D.; Gehrels, N.; Germani, S.; Giglietto, N.; Giordano, F.; Glanzman, T.; Godfrey, G.; Granot, J.; Grenier, I. A.; Grondin, M.-H.; Grove, J. E.; Guiriec, S.; Hadasch, D.; Harding, A. K.; Hays, E.; Horan, D.; Hughes, R. E.; Jóhannesson, G.; Johnson, W. N.; Kamae, T.; Katagiri, H.; Kataoka, J.; Kawai, N.; Kippen, R. M.; Knödlseder, J.; Kocevski, D.; Kouveliotou, C.; Kuss, M.; Lande, J.; Latronico, L.; Lemoine-Goumard, M.; Llena Garde, M.; Longo, F.; Loparco, F.; Lott, B.; Lovellette, M. N.; Lubrano, P.; Makeev, A.; Mazziotta, M. N.; McEnery, J. E.; McGlynn, S.; Meegan, C.; Mészáros, P.; Michelson, P. F.; Mitthumsiri, W.; Mizuno, T.; Moiseev, A. A.; Monte, C.; Monzani, M. E.; Moretti, E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Nakajima, H.; Nakamori, T.; Nolan, P. L.; Norris, J. P.; Nuss, E.; Ohno, M.; Ohsugi, T.; Omodei, N.; Orlando, E.; Ormes, J. F.; Ozaki, M.; Paciesas, W. S.; Paneque, D.; Panetta, J. H.; Parent, D.; Pelassa, V.; Pepe, M.; Pesce-Rollins, M.; Piron, F.; Preece, R.; Rainò, S.; Rando, R.; Razzano, M.; Razzaque, S.; Reimer, A.; Ritz, S.; Rodriguez, A. Y.; Roth, M.; Ryde, F.; Sadrozinski, H. F.-W.; Sander, A.; Scargle, J. D.; Schalk, T. L.; Sgrò, C.; Siskind, E. J.; Smith, P. D.; Spandre, G.; Spinelli, P.; Stamatikos, M.; Stecker, F. W.; Strickman, M. S.; Suson, D. J.; Tajima, H.; Takahashi, H.; Takahashi, T.; Tanaka, T.; Thayer, J. B.; Thayer, J. G.; Thompson, D. J.; Tibaldo, L.; Toma, K.; Torres, D. F.; Tosti, G.; Tramacere, A.; Uchiyama, Y.; Uehara, T.; Usher, T. L.; van der Horst, A. J.; Vasileiou, V.; Vilchez, N.; Vitale, V.; von Kienlin, A.; Waite, A. P.; Wang, P.; Wilson-Hodge, C.; Winer, B. L.; Wu, X. F.; Yamazaki, R.; Yang, Z.; Ylinen, T.; Ziegler, M.

    2010-06-01

    We present detailed observations of the bright short-hard gamma-ray burst GRB 090510 made with the Gamma-ray Burst Monitor (GBM) and Large Area Telescope (LAT) on board the Fermi observatory. GRB 090510 is the first burst detected by the LAT that shows strong evidence for a deviation from a Band spectral fitting function during the prompt emission phase. The time-integrated spectrum is fit by the sum of a Band function with E peak = 3.9 ± 0.3 MeV, which is the highest yet measured, and a hard power-law component with photon index -1.62 ± 0.03 that dominates the emission below ?20 keV and above ?100 MeV. The onset of the high-energy spectral component appears to be delayed by ~0.1 s with respect to the onset of a component well fit with a single Band function. A faint GBM pulse and a LAT photon are detected 0.5 s before the main pulse. During the prompt phase, the LAT detected a photon with energy 30.5+5.8 -2.6 GeV, the highest ever measured from a short GRB. Observation of this photon sets a minimum bulk outflow Lorentz factor, ?gsim 1200, using simple ?? opacity arguments for this GRB at redshift z = 0.903 and a variability timescale on the order of tens of ms for the ?100 keV-few MeV flux. Stricter high confidence estimates imply ? >~ 1000 and still require that the outflows powering short GRBs are at least as highly relativistic as those of long-duration GRBs. Implications of the temporal behavior and power-law shape of the additional component on synchrotron/synchrotron self-Compton, external-shock synchrotron, and hadronic models are considered.

  17. Radiation hardness of high-Q silicon nitride microresonators for space compatible integrated optics.

    PubMed

    Brasch, Victor; Chen, Qun-Feng; Schiller, Stephan; Kippenberg, Tobias J

    2014-12-15

    Integrated optics has distinct advantages for applications in space because it integrates many elements onto a monolithic, robust chip. As the development of different building blocks for integrated optics advances, it is of interest to answer the important question of their resistance with respect to ionizing radiation. Here we investigate effects of proton radiation on high-Q (?(10?)) silicon nitride microresonators formed by a waveguide ring. We show that the irradiation with high-energy protons has no lasting effect on the linear optical losses of the microresonators. PMID:25607027

  18. Investigation of K-shell radiation from two-component wire arrays

    NASA Astrophysics Data System (ADS)

    Papp, Daniel; Ivanov, Vladimir; Mancini, Roberto; Hakel, Peter; Altemara, Sara; Anderson, Austin

    2012-10-01

    Two-component plasma was studied in star and planar wire-array Z pinches. Arrays consisted of Al wires as the first component in all shots and Ti, Cu, Ni, Mo, and Au wires as the second component. Cascading implosion in star arrays provides the mixing of wire materials in one ray during implosion. The implosion dynamic was not affected by variation of materials in wire arrays that allows observation of features of the two-component plasma. Compared to pure Al plasmas, decreased Al K-shell radiation and increased soft x-ray radiation were observed in Al-Au and Al-W plasma. Mixt plasma with 80-90% of Al ions displayed radiative properties similar to pure W or Au Z-pinch plasma. Al K-shell x-ray spectra simulations with the PrismSpect code showed a fall of the electron temperature from 400 eV in Al plasma to 250-300 eV in the Al-W and Al-Au mix. There was no corresponding cooling effect when the second component was Ti, Cu, and Ni. Spectra of the Z-pinch plasmas were compared with the spectra from laser produced Al-Au plasma experiments carried out at the Leopard laser. Work was supported by the DOE/NNSA under UNR grant DE-FC52-06NA27616.

  19. Radiation studies of optical and electronic components used in astronomical satellite studies

    NASA Technical Reports Server (NTRS)

    Becher, J.; Kernell, R. L.

    1981-01-01

    The synchronous orbit of the IUE carries the satellite through Earth's outer electron belt. A 40 mCi Sr90 source was used to simulate these electrons. A 5 mCi source of Co60 was used to simulate bremmstrahlung. A 10 MeV electron Linac and a 1.7 MeV electron Van de Graaf wer used to investigate the energy dependence of radiation effects and to perform radiations at a high flux rate. A 100 MeV proton cyclotron was used to simulate cosmic rays. Results are presented for three instrument systems of the IUE and measurements for specific components are reported. The three instrument systems were the ultraviolet converter, the fine error sensor (FES), and the SEC vidicon camera tube. The components were optical glasses, electronic components, silicon photodiodes, and UV window materials.

  20. Nano and Micro Structures Image Based on Lens-Crystal System For Hard X-Ray Radiation

    NASA Astrophysics Data System (ADS)

    Kuyumchyan, David; Kuyumchyan, Armen; Kohn, Victor; Snigirev, Anatoly; Snigireva, Irina; Shulakov, Evgeny

    2012-02-01

    We present results of imaging properties of the lens-crystal system for hard x-ray radiation. The system is based on a beryllium parabolic refractive lens placed in front of the sample, and an asymmetric silicon single crystal placed behind the sample. We record the magnified x-ray phase contrast image at the x-ray energy 15 keV. The peculiarities of image transformation are investigated both experimentally and theoretically when the focus of refractive lens is moved across and along the optical axis. The computer program was elaborated for a simulation of image formation in the system based on the refractive lens and the crystal with asymmetric Bragg diffraction. The algorithm is based on the FFT procedure.

  1. Estimation of the biological danger of the very high energy component of space radiation.

    PubMed

    Akoev, I G; Yurov, S S; Leontyeva, G A; Livanova, I A; Achmadiyeva, A H; Fomenko, B S; Lebedev, V N; Lukanin, V N

    1973-01-01

    In modelling the action of the high energy component of space radiation in a space ship, the secondary radiation resulting from the interaction of 76 GeV protons with a target was used. The radiation flow consisted of neutrons, mesons of different kinds and charges, protons and gamma-quanta of wide energy spectrum. We studied the influence of radiation on the survival of E. coli B and T4Br+ bacteriophage, on the growth, dry weight and survival of Vicia faba, on the frequency of chromosome aberrations, and number of cells with abnormal mitoses, on the rate of post-irradiation recovery according to these characteristics, and also on the yield of the r-mutants of T4Br+ bacteriophage, their distribution and biochemical identification. The probability of strong interactions with intra-nuclear cascade processes was minor. Their action on the background of the main mass of radiation with an RBE of less than 1 could be considerably masked. Nevertheless, the RBE of combined secondary radiation was sufficiently greater than 137Cs radiation; from approximate curves, it was from 1.2 to 4.0 times as great and in single experimental points it was more than 5. The spectrum of mutation was also different. PMID:12523384

  2. Principal Component-Based Radiative Transfer Model (PCRTM) for Hyperspectral Sensors. Part I; Theoretical Concept

    NASA Technical Reports Server (NTRS)

    Liu, Xu; Smith, William L.; Zhou, Daniel K.; Larar, Allen

    2005-01-01

    Modern infrared satellite sensors such as Atmospheric Infrared Sounder (AIRS), Cosmic Ray Isotope Spectrometer (CrIS), Thermal Emission Spectrometer (TES), Geosynchronous Imaging Fourier Transform Spectrometer (GIFTS) and Infrared Atmospheric Sounding Interferometer (IASI) are capable of providing high spatial and spectral resolution infrared spectra. To fully exploit the vast amount of spectral information from these instruments, super fast radiative transfer models are needed. This paper presents a novel radiative transfer model based on principal component analysis. Instead of predicting channel radiance or transmittance spectra directly, the Principal Component-based Radiative Transfer Model (PCRTM) predicts the Principal Component (PC) scores of these quantities. This prediction ability leads to significant savings in computational time. The parameterization of the PCRTM model is derived from properties of PC scores and instrument line shape functions. The PCRTM is very accurate and flexible. Due to its high speed and compressed spectral information format, it has great potential for super fast one-dimensional physical retrievals and for Numerical Weather Prediction (NWP) large volume radiance data assimilation applications. The model has been successfully developed for the National Polar-orbiting Operational Environmental Satellite System Airborne Sounder Testbed - Interferometer (NAST-I) and AIRS instruments. The PCRTM model performs monochromatic radiative transfer calculations and is able to include multiple scattering calculations to account for clouds and aerosols.

  3. On the problem of the radiation hardness of SiC nuclear radiation detectors at high working temperatures

    SciTech Connect

    Ivanov, A. M., E-mail: Alexandr.Ivanov@mail.ioffe.ru; Sadokhin, A. V.; Strokan, N. B.; Lebedev, A. A. [Russian Academy of Sciences, Ioffe Physical Technical Institute (Russian Federation)

    2011-10-15

    Owing to the radiation-induced pronounced conductivity compensation in silicon carbide, carrier localization (trapping) prevails over recombination in capture of nonequilibrium carriers. This makes it possible, by raising the temperature, to reduce the time of carrier retention by a trapping center to values shorter than the duration of signal shaping by electronic circuits. For structural defects created by 6.5-MeV protons, the temperature excluding degradation of the detector signal via carrier localization is estimated. The values of the appearing generation current the noise of which can restrict the operation of a detector in the spectrometric mode are determined.

  4. Radiative cooling of two-component wire-array Z-pinch plasma

    SciTech Connect

    Ivanov, V. V.; Mancini, R. C.; Papp, D.; Hakel, P.; Durmaz, T. [Department of Physics, University of Nevada, Reno, Nevada 89557 (United States); Florido, R. [Department of Physics, University of Nevada, Reno, Nevada 89557 (United States); Departamento de Física, Universidad de Las Palmas de Gran Canaria, 35017 Las Palmas de Gran Canaria (Spain)

    2014-08-15

    Wire-array two-component Z-pinch plasmas containing Al and other elements were studied experimentally and the observations interpreted with the help of theoretical modeling. Special attention was given to achieving reproducible implosions. Cascading implosions in star wire arrays mix components during the implosion phase and implosion dynamics were not affected by changes in concentration. A reduction in Al K-shell radiation and an increase in soft x-ray radiation emission were observed in Al-W plasma with 84% concentration of Al ions compared to only-Al plasma. Plasma with 84% of Al ions has radiative properties like those of W Z-pinches. The analysis of Al K-shell x-ray spectra with a collisional-radiative atomic kinetics model shows a drop of the electron temperature from 400?eV in pure Al plasma to below 300?eV in the Al-W mix. Al-Au Z-pinches present radiation features similar to Al-W plasma. This is indicative of a similar plasma cooling effect due to the presence of a high-Z element.

  5. Improved Hardness of Single-Crystal ${\\\\rm Nd}^{3+}:{\\\\rm YAG}$ to Ionizing Radiation via Co-Doping with ${\\\\rm Cr}^{3+}$

    Microsoft Academic Search

    Boris L. Glebov; Kelly Simmons-Potter; Brian P. Fox; Dorothy C. Meister

    2012-01-01

    The proliferation of optical elements in systems that are subject to harsh ionizing radiation environments prompts the need for commercially available radiation-hard materials, such as laser materials. In the present study, changes in the material optical absorption are compared for a suite of single-crystal YAG, ${\\\\rm Nd}^{3+}:{\\\\rm YAG}$, and ${\\\\rm Cr}^{3+},{\\\\rm Nd}^{3+}:{\\\\rm YAG}$ laser materials in response to high-dose-rate gamma

  6. The degradation of TPX components by oxygen, elevated temperature, and ionizing radiation

    SciTech Connect

    Farmer, J.C.

    1996-05-31

    TPX is PMP or poly(4-methyl-1-pentene). It has several commercially important characteristics such as high optical transparency, high crystalline melting point, etc., leading to numerous applications including infrared windows, lenses, membranes, food packaging. The life components fabricated from this material may be limited by thermal oxidative and radiation-induced degradation. A preliminary review of the scientific literature was conducted to obtain relevant information on the effects of oxygen, moisture elevated temperature, and radiation on the chemical, thermodynamic, mechanical, and electrical properties of this material. Refs, figs, tabs.

  7. ID22: a multitechnique hard X-ray microprobe beamline at the European Synchrotron Radiation Facility.

    PubMed

    Somogyi, A; Tucoulou, R; Martinez-Criado, G; Homs, A; Cauzid, J; Bleuet, P; Bohic, S; Simionovici, A

    2005-03-01

    The ID22 beamline is dedicated to hard X-ray microanalysis allowing the combination of fluorescence, spectroscopy, diffraction and tomography techniques in a wide energy range from 6 to 70 keV. The recent installation of an in-vacuum undulator, a new sample stage and the adaptation of various focusing optics has contributed to a great improvement in the capabilities of the beamline, which is now accessed by a wide user community issued from medical, earth and environmental science, archaeology and material science. Many applications requiring low detection limits for localization/speciation of trace elements together with structural analysis have been developed at the beamline on the (sub)micrometer scale. The possibility of combining simultaneously different analytical probes offers the opportunity of a thorough study of a given sample or scientific problem. This paper presents a review of the recent developments of the beamline and a detailed description of its capabilities through examples from different fields of applications. PMID:15728973

  8. Radiation-hard Active Pixel Sensors for HL-LHC Detector Upgrades based on HV-CMOS Technology

    NASA Astrophysics Data System (ADS)

    Miucci, A.; Gonella, L.; Hemperek, T.; Hügging, F.; Krüger, H.; Obermann, T.; Wermes, N.; Garcia-Sciveres, M.; Backhaus, M.; Capeans, M.; Feigl, S.; Nessi, M.; Pernegger, H.; Ristic, B.; Gonzalez-Sevilla, S.; Ferrere, D.; Iacobucci, G.; La Rosa, A.; Muenstermann, D.; George, M.; Große-Knetter, J.; Quadt, A.; Rieger, J.; Weingarten, J.; Bates, R.; Blue, A.; Buttar, C.; Hynds, D.; Kreidl, C.; Peric, I.; Breugnon, P.; Pangaud, P.; Godiot-Basolo, S.; Fougeron, D.; Bompard, F.; Clemens, J. C.; Liu, J.; Barbero, M.; Rozanov, A.; HV-CMOS Collaboration

    2014-05-01

    Luminosity upgrades are discussed for the LHC (HL-LHC) which would make updates to the detectors necessary, requiring in particular new, even more radiation-hard and granular, sensors for the inner detector region. A proposal for the next generation of inner detectors is based on HV-CMOS: a new family of silicon sensors based on commercial high-voltage CMOS technology, which enables the fabrication of part of the pixel electronics inside the silicon substrate itself. The main advantages of this technology with respect to the standard silicon sensor technology are: low material budget, fast charge collection time, high radiation tolerance, low cost and operation at room temperature. A traditional readout chip is still needed to receive and organize the data from the active sensor and to handle high-level functionality such as trigger management. HV-CMOS has been designed to be compatible with both pixel and strip readout. In this paper an overview of HV2FEI4, a HV-CMOS prototype in 180 nm AMS technology, will be given. Preliminary results after neutron and X-ray irradiation are shown.

  9. Radiation-hard Active Pixel Sensors for HL-LHC Detector Upgrades based on HV-CMOS Technology

    E-print Network

    Miucci, A et al.

    2014-01-01

    Luminosity upgrades are discussed for the LHC (HL-LHC) which would make updates to the detectors necessary, requiring in particular new, even more radiation-hard and granular, sensors for the inner detector region. 1Corresponding author. c CERN 2014, published under the terms of the Creative Commons Attribution 3.0 License by IOP Publishing Ltd and Sissa Medialab srl. Any further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation and DOI. doi:10.1088/1748-0221/9/05/C050642014 JINST 9 C05064 A proposal for the next generation of inner detectors is based on HV-CMOS: a new family of silicon sensors based on commercial high-voltage CMOS technology, which enables the fabrication of part of the pixel electronics inside the silicon substrate itself. The main advantages of this technology with respect to the standard silicon sensor technology are: low material budget, fast charge collection time, high radiation tolerance, low cost and operation a...

  10. Cryogenic and radiation hard ASIC design for large format NIR/SWIR detector

    NASA Astrophysics Data System (ADS)

    Gao, Peng; Dupont, Benoit; Dierickx, Bart; Müller, Eric; Verbruggen, Geert; Gielis, Stijn; Valvekens, Ramses

    2014-10-01

    An ASIC is developed to control and data quantization for large format NIR/SWIR detector arrays. Both cryogenic and space radiation environment issue are considered during the design. Therefore it can be integrated in the cryogenic chamber, which reduces significantly the vast amount of long wires going in and out the cryogenic chamber, i.e. benefits EMI and noise concerns, as well as the power consumption of cooling system and interfacing circuits. In this paper, we will describe the development of this prototype ASIC for image sensor driving and signal processing as well as the testing in both room and cryogenic temperature.

  11. STUDY OF THE RADIATION HARDNESS OF VCSEL AND PIN K.K. GAN, W. FERNANDO, H.P. KAGAN, R.D. KASS, A. LAW,

    E-print Network

    Gan, K. K.

    are therefore 69 and 34 Mrad, respectively. We irradiated optical modules instrumented with one silicon PIN1 STUDY OF THE RADIATION HARDNESS OF VCSEL AND PIN ARRAYS K.K. GAN, W. FERNANDO, H.P. KAGAN, R. VCSEL arrays operating at 850 nm are used to transmit optical signals while PIN arrays are used

  12. Radiation hardness properties of full-3D active edge silicon sensors

    NASA Astrophysics Data System (ADS)

    Da Viá, C.; Hasi, J.; Kenney, C.; Linhart, V.; Parker, Sherwood; Slavicek, T.; Watts, S. J.; Bem, P.; Horazdovsky, T.; Pospisil, S.

    2008-03-01

    Full-three-dimensional (3D) pixel sensors, with electrodes penetrating through the entire silicon wafer, were fabricated at the Stanford Nanofabrication Facility, Stanford, California, USA. They have 71-?m-inter-electrode spacing, active edges and a compatible geometry to the ATLAS pixel detector readout electronics. Several samples were irradiated with neutrons to different doses up to an equivalent fluence of 8.6×10 15 n 1 MeVeq cm -2. This corresponds to the integrated fluence expected after ˜5 years at the Large Hadron Collider (LHC) with a luminosity of 10 35 cm -2 s -1 at 4 cm from the interaction point, where the ATLAS B-Layer is placed. Before and after irradiation, signals were generated by a 1060 nm infrared laser calibrated to inject a charge of 14 fC. This corresponds to ˜3.5 minimum ionizing particles and should not perturb the charge status of the radiation-induced defects. After 8.6×10 15 n 1 MeVeq cm -2 the signal collected was ˜38% and corresponded to ˜7200e - for a substrate thickness of 235 ?m. Signal efficiency, radiation-induced leakage current and related damage parameters are discussed here and compared with simulations. Full-3D silicon detectors with active edges are being considered for forward proton tagging at the LHC, for the ATLAS pixel B-layer replacement and for the ATLAS pixel upgrade.

  13. Product assurance technology for procuring reliable, radiation-hard, custom LSI/VLSI electronics

    NASA Technical Reports Server (NTRS)

    Buehler, M. G.; Allen, R. A.; Blaes, B. R.; Hicks, K. A.; Jennings, G. A.; Lin, Y.-S.; Pina, C. A.; Sayah, H. R.; Zamani, N.

    1989-01-01

    Advanced measurement methods using microelectronic test chips are described. These chips are intended to be used in acquiring the data needed to qualify Application Specific Integrated Circuits (ASIC's) for space use. Efforts were focused on developing the technology for obtaining custom IC's from CMOS/bulk silicon foundries. A series of test chips were developed: a parametric test strip, a fault chip, a set of reliability chips, and the CRRES (Combined Release and Radiation Effects Satellite) chip, a test circuit for monitoring space radiation effects. The technical accomplishments of the effort include: (1) development of a fault chip that contains a set of test structures used to evaluate the density of various process-induced defects; (2) development of new test structures and testing techniques for measuring gate-oxide capacitance, gate-overlap capacitance, and propagation delay; (3) development of a set of reliability chips that are used to evaluate failure mechanisms in CMOS/bulk: interconnect and contact electromigration and time-dependent dielectric breakdown; (4) development of MOSFET parameter extraction procedures for evaluating subthreshold characteristics; (5) evaluation of test chips and test strips on the second CRRES wafer run; (6) two dedicated fabrication runs for the CRRES chip flight parts; and (7) publication of two papers: one on the split-cross bridge resistor and another on asymmetrical SRAM (static random access memory) cells for single-event upset analysis.

  14. Radiation tests of key components of the ALICE TOF TDC Readout Module

    Microsoft Academic Search

    A. Alici; P. Antonioli; A. Mati; S. Meneghini; M. Pieracci; M. Rizzi; C. Tintori

    The ALICE Time-of-Flight (TOF) system will be a large area (140 m 2 ) detector made by Multigap Resistive Plate Chambers (MRPC). The read-out will be performed by a VME TDC Readout Module (TRM) hosting each 30 High Performance TDC chips (HPTDC). Radiation tests carried out at Zurich PSI with a 60 MeV proton beam line on key components of

  15. An evaluation of radiation damage to solid state components flown in low earth orbit satellites.

    PubMed

    Shin, Myung-Won; Kim, Myung-Hyun

    2004-01-01

    The effects of total ionising radiation dose upon commercial off-the-shelf semiconductors fitted to satellites operating in low Earth orbit (LEO) conditions was evaluated. The evaluation was performed for the Korea Institute of Technology SATellite-1, (KITSAT-1) which was equipped with commercial solid state components. Two approximate calculation models for space radiation shielding were developed. Verification was performed by comparing the results with detailed three-dimensional calculations using the Monte-Carlo method and measured data from KITSAT-1. It was confirmed that the developed approximate models were reliable for satellite shielding calculations. It was also found that commercial semiconductor devices, which were not radiation hardened, could be damaged within their lifetime due to the total ionising dose they are subject to in the LEO environment. To conclude, an intensive shielding analysis should be considered when commercial devices are used. PMID:15103058

  16. Beta Backscatter Measures the Hardness of Rubber

    NASA Technical Reports Server (NTRS)

    Morrissey, E. T.; Roje, F. N.

    1986-01-01

    Nondestructive testing method determines hardness, on Shore scale, of room-temperature-vulcanizing silicone rubber. Measures backscattered beta particles; backscattered radiation count directly proportional to Shore hardness. Test set calibrated with specimen, Shore hardness known from mechanical durometer test. Specimen of unknown hardness tested, and radiation count recorded. Count compared with known sample to find Shore hardness of unknown.

  17. [Changes in chemistry component structure and microstructure characterization of acetylated wood before and after UV radiation].

    PubMed

    Fu, Zhan; Liu, Yi; Xing, Fang-Ru; Guo, Hong-Wu

    2014-11-01

    The poplar powder was acetylated with different duration as sample, processed ray radiation by using ultraviolet test box, contrasting the influences to lightfastness of wood with different acetylation degree, analyzing changing rules of characteristic peaks' intensity which belonged to the chemistry components of samples based on FTIR spectra, and the relationship between duration of acetylation and changes of chemistry components was established, The results showed that: Before UV radiation, the characteristic peaks' intensity of acetylated poplar powder at 1 739 cm(-1) which belonged to C = O in saturated esters compounds and 1 385 cm(-1) which belonged to C-H in acetate were higher than untreated ones', the poplar powder with 40 min's acetylation has the highest characteristic peaks' intensity, highest weight gain rate, remarkable acetylation effect; After UV radiation, characteristic peaks' intensity of Benzene at 1 504 cm(-1) which belonged to lignin of poplar powder was obviously higher than untreated ones', and characteristic peaks' intensity of poplar powder with 40 min's acetylation was the highest, this showed that acetylation could effectively reduce the light degradation of wood chemistry components, in order to improve the lightfastness, especially the poplar powder with 40 min's acetylation; SEM photos showed that, the fibrous surface of acetylated poplar powder was more smooth and had more narrow particle size than untreated ones', so acetylation can effectively improve the stability of wood. PMID:25752036

  18. Hard X-ray nanofocusing at low-emittance synchrotron radiation sources.

    PubMed

    Schroer, Christian G; Falkenberg, Gerald

    2014-09-01

    X-ray scanning microscopy relies on intensive nanobeams generated by imaging a highly brilliant synchrotron radiation source onto the sample with a nanofocusing X-ray optic. Here, using a Gaussian model for the central cone of an undulator source, the nanobeam generated by refractive X-ray lenses is modeled in terms of size, flux and coherence. The beam properties are expressed in terms of the emittances of the storage ring and the lateral sizes of the electron beam. Optimal source parameters are calculated to obtain efficient and diffraction-limited nanofocusing. With decreasing emittance, the usable fraction of the beam for diffraction-limited nanofocusing experiments can be increased by more than two orders of magnitude compared with modern storage ring sources. For a diffraction-limited storage ring, nearly the whole beam can be focused, making these sources highly attractive for X-ray scanning microscopy. PMID:25177988

  19. The performance and radiation hardness of the Outer Tracker detector for LHCb

    NASA Astrophysics Data System (ADS)

    Gersabeck, E.

    2014-06-01

    The LHCb experiment is designed to study B and D-meson decays at the LHC, in the forward region. It is crucial to accurately and efficiently detect the charged decay particles in the high-density particle environment of the LHC. For this, the Outer Tracker (OT) has been constructed. The detector has operated reliably under the challenging LHC conditions in 2011 and 2012. The performance of the detector is discussed in terms of high voltage stability, noise rate and single hit efficiency. New results on the hit resolution are presented. Finally, latest results on the radiation tolerance of this sensitive gas detector are discussed, after having received a total dose corresponding to about 100 mC/cm in the hottest region, and having operated with proton-ion collisions in 2013.

  20. Depletion layer recombination effects on the radiation damage hardness of gallium arsenide cells

    NASA Technical Reports Server (NTRS)

    Garlick, G. F. J.

    1985-01-01

    The significant effect of junction depletion layer recombination on the efficiency of windowed GaAs cells was demonstrated. The effect becomes more pronounced as radiation damage occurs. The depletion is considered for 1 MeV electron fluences up to 10 to the 16th power e/sq m. The cell modeling separates damage in emitter and base or buffer layers using different damage coefficients is reported. The lower coefficient for the emitter predicts less loss of performance at fluences greater than 10 to the 15th power e/sq cm. A method for obtaining information on junction recombination effects as damage proceeds is described; this enables a more complete diagnosis of damage to be made.

  1. Hard X-ray nanofocusing at low-emittance synchrotron radiation sources

    PubMed Central

    Schroer, Christian G.; Falkenberg, Gerald

    2014-01-01

    X-ray scanning microscopy relies on intensive nanobeams generated by imaging a highly brilliant synchrotron radiation source onto the sample with a nanofocusing X-ray optic. Here, using a Gaussian model for the central cone of an undulator source, the nanobeam generated by refractive X-ray lenses is modeled in terms of size, flux and coherence. The beam properties are expressed in terms of the emittances of the storage ring and the lateral sizes of the electron beam. Optimal source parameters are calculated to obtain efficient and diffraction-limited nanofocusing. With decreasing emittance, the usable fraction of the beam for diffraction-limited nanofocusing experiments can be increased by more than two orders of magnitude compared with modern storage ring sources. For a diffraction-limited storage ring, nearly the whole beam can be focused, making these sources highly attractive for X-ray scanning microscopy. PMID:25177988

  2. A Radiation Hard Multi-Channel Digitizer ASIC for Operation in the Harsh Jovian Environment

    NASA Technical Reports Server (NTRS)

    Aslam, Shahid; Aslam, S.; Akturk, A.; Quilligan, G.

    2011-01-01

    In 1995, the Galileo spacecraft arrived at Jupiter to conduct follow-up experiments on pathfinder Pioneer and key Voyager discoveries especially at Io, Europa, Ganymede and Callisto. These new observations helped expand our scientific knowledge of the prominent Galilean satellites; studies revealed diversity with respect to their geology, internal structure, evolution and degree of past and present activity. Jupiter's diverse Galilean satellites, of which three are believed to harbor internal oceans, are central to understanding the habitability of icy worlds. Galileo provided for the first time compelling evidence of a near-surface global ocean on Europa. Furthermore, by understanding the Jupiter system and unraveling the history of its evolution from initial formation to the emergence of possible habitats and life, gives insight into how giant planets and their satellite systems form and evolve. Most important, new light is shed on the potential for the emergence and existence of life in icy satellite oceans. In 2009, NASA released a detailed Jupiter Europa Mission Study (EJSM) that proposed an ambitious Flagship Mission to understand more fully the satellites Europa and Ganymede within the context of the Jovian system. Key to EJSM is the NASA led Jupiter Europa Orbiter (JEO) and the ESA led Jupiter Ganymede Orbiter (JGO). JEO and JGO would execute a choreographed exploration of the Jovian system before settling into orbit around Europa and Ganymede, respectively. The National Academies Planetary Decadal Survey, 2011 has listed the NASA-led JEO as the second highest priority mission for the decade 2013-2022, and if chosen it would be launched in 2020 with arrival at Jupiter in 2025. If the JEO mission is not chosen it is anticipated that there will be opportunities in future decadal cycles. Jupiter Orbit Insertion (JOI) begins a 30-month Jovian system tour followed by nine months of science mapping after Europa Orbit Insertion (EOI) in July 2028. The orbiter will ultimately impact the surface of Europa after the mission is completed. The current JEO mission concept includes a range of instruments on the payload, to monitor dynamic phenomena (such as Io's volcanoes and Jupiters atmosphere), map the Jovian magnetosphere and its interactions with the Galilean satellites, and characterize water oceans beneath the ice shells of Europa and Ganymede. The payload includes a low mass (3.7 Kg) and low power (< 5 W) Thermal Instrument (TI) concept for measuring possible warm thermal anomalies on Europa s cold surface caused by recent (< 10,000 years) eruptive activity. Regions of anomalously high heat flow will be identified by thermal mapping using a nadir pointing, push-broom filter radiometer that provides far-IR imagery in two broad band spectral wavelength regions, 8-20 m and 20-100 m, for surface temperature measurements with better than a 2 K accuracy and a spatial resolution of 250 m/pixel obtained from a 100 Km orbit. The temperature accuracy permits a search for elevated temperatures when combined with albedo information. The spatial resolution is sufficient to resolve Europa's larger cracks and ridge axial valleys. In order to accomplish the thermal mapping, the TI uses sensitive thermopile arrays that are readout by a custom designed low-noise Multi-Channel Digitizer (MCD) ASIC that resides very close to the thermopile linear array outputs. Both the thermopile array and the MCD ASIC will need to show full functionality within the harsh Jovian radiation environment, operating at cryogenic temperatures, typically 150 K to 170 K. In the following, a radiation mitigation strategy together with a low risk Radiation-Hardened-By-Design (RHBD) methodology using commercial foundry processes is given for the design and manufacture of a MCD ASIC that will meet this challenge.

  3. Heat loads to divertor nearby components from secondary radiation evolved during plasma instabilities

    NASA Astrophysics Data System (ADS)

    Sizyuk, V.; Hassanein, A.

    2015-01-01

    A fundamental issue in tokamak operation related to power exhaust during plasma instabilities is the understanding of heat and particle transport from the core plasma into the scrape-off layer and to plasma-facing materials. During abnormal and disruptive operation in tokamaks, radiation transport processes play a critical role in divertor/edge-generated plasma dynamics and are very important in determining overall lifetimes of the divertor and nearby components. This is equivalent to or greater than the effect of the direct impact of escaped core plasma on the divertor plate. We have developed and implemented comprehensive enhanced physical and numerical models in the upgraded HEIGHTS package for simulating detailed photon and particle transport in the evolved edge plasma during various instabilities. The paper describes details of a newly developed 3D Monte Carlo radiation transport model, including optimization methods of generated plasma opacities in the full range of expected photon spectra. Response of the ITER divertor's nearby surfaces due to radiation from the divertor-developed plasma was simulated by using actual full 3D reactor design and magnetic configurations. We analyzed in detail the radiation emission spectra and compared the emission of both carbon and tungsten as divertor plate materials. The integrated 3D simulation predicted unexpectedly high damage risk to the open stainless steel legs of the dome structure in the current ITER design from the intense radiation during a disruption on the tungsten divertor plate.

  4. One more surprise from the Circinus Galaxy: BeppoSAX discovery of a transmission component in hard X-rays

    NASA Astrophysics Data System (ADS)

    Matt, G.; Guainazzi, M.; Maiolino, R.; Molendi, S.; Perola, G. C.; Antonelli, L. A.; Bassani, L.; Brandt, W. N.; Fabian, A. C.; Fiore, F.; Iwasawa, K.; Malaguti, G.; Marconi, A.; Poutanen, J.

    1999-01-01

    The Circinus Galaxy has been observed, for the first time above 10 keV, by BeppoSAX. An excess emission above the extrapolation of the best fit 0.1-10 keV spectrum is apparent in the PDS data. The most likely explanation is that we are observing the nucleus through a column density of ~ 4*E(24) cm(-2) , i.e. large enough to completely block the radiation below 10 keV but small enough to permit partial transmission above this energy.

  5. Proposal to produce novel, transparent radiation hard low refractive index polymers. Final report, 1 October-31 December 1993

    SciTech Connect

    Schuman, P.D.; Harmon, J.

    1994-02-09

    Low and high molecular weight polymers of heptafluorobutyl methacrylate, HFBM, were prepared for commercial evaluation by Bicron, an optical fiber manufacturer. Polymers were evaluated as low refractive index fiber cladding materials. Test results of Low MW polymer solutions gave excellent results. Higher MW polymers were prepared for cladding by melt co-extrusion. Corning Glass Corp, also expressed an interest in these cladding materials. These results appear to be sufficiently unique that a search has been initiated to determine patentability of the soluble fluorocarbon acrylate, methacrylate and copolymer compositions for cladding use. This research resulted in identifying a radiation hard, low refractive index polymer, poly(heptafluorobutyl methacrylate), P(HFBM) as the best candidate for a novel cladding material. P(HFBM) has a refractive index of 1.387. When used to clad a styrene core, the theoretical light propagation efficiency is 50% greater than that of styrene fiber core clad with PMMA, a common commercial cladding material. These polymers will be the only commercial fluorocarbon acrylic cladding polymers available to U.S. manufacturers. Japanese optical fiber manufacturers produce fluorocarbon clad fibers but their polymers are not available to U.S. manufacturers. These polymers can fill an urgent need in the optical fiber market.

  6. Recent results of CERN RD39 collaboration on development of radiation hard Si detectors operated at low to cryogenic temperatures

    NASA Astrophysics Data System (ADS)

    Li, Zheng; Chen, W.; Eremin, V.; Ha¨rko¨nen, J.; Luukka, P.; Tuominen, E.; Tuovinen, E.; Verbitskaya, E.

    2013-08-01

    Recent results of CERN RD39 collaboration on the development of radiation hard Si detectors operated at low to cryogenic temperatures will be presented in this paper. It has been found, in comparisons of results of simulation and charge collection data of pad and strip detectors, the charge-injected-diode (CID) operation mode of Si detectors reduces the free carrier trapping, resulting in a much higher charge collection at the SLHC fluence than that in a standard Si detector. The reduction in free carrier trapping by almost a factor of 3 is due to the fact that the CID mode pre-fills the traps, making them neutral and not active in trapping of particle-induced free carriers (signal). It has been found that, electron traps can be pre-filled by injection of electrons from the n+ contact. The CID mode of detector operation can be achieved by a modestly low temperature of ?-40 °C and a operation bias of <600 V. Results of one CID detector application as LHC beam-loss-monitor (BLM) will be presented. Non-irradiated Si detectors has been shown, with tests by laser using our cryogenic transient-current-technique (TCT), to work quite well at LHe temperature (4 K), which are very stable with no polarization and good charge collection efficiency.

  7. Principal component analysis and radiative transfer modelling of Spitzer Infrared Spectrograph spectra of ultraluminous infrared galaxies

    NASA Astrophysics Data System (ADS)

    Hurley, P. D.; Oliver, S.; Farrah, D.; Wang, L.; Efstathiou, A.

    2012-08-01

    The mid-infrared spectra of ultraluminous infrared galaxies (ULIRGs) contain a variety of spectral features that can be used as diagnostics to characterize the spectra. However, such diagnostics are biased by our prior prejudices on the origin of the features. Moreover, by using only part of the spectrum they do not utilize the full information content of the spectra. Blind statistical techniques such as principal component analysis (PCA) consider the whole spectrum, find correlated features and separate them out into distinct components. We further investigate the principal components (PCs) of ULIRGs derived in Wang et al. We quantitatively show that five PCs are optimal for describing the Infrared Spectrograph spectra. These five components (PC1-PC5) and the mean spectrum provide a template basis set that reproduces spectra of all z < 0.35 ULIRGs within the noise. For comparison, the spectra are also modelled with a combination of radiative transfer models of both starbursts and the dusty torus surrounding active galactic nuclei (AGN). The five PCs typically provide better fits than the models. We argue that the radiative transfer models require a colder dust component and have difficulty in modelling strong polycyclic aromatic hydrocarbon features. Aided by the models we also interpret the physical processes that the PCs represent. The third PC is shown to indicate the nature of the dominant power source, while PC1 is related to the inclination of the AGN torus. Finally, we use the five PCs to define a new classification scheme using 5D Gaussian mixture modelling and trained on widely used optical classifications. The five PCs, average spectra for the four classifications and the code to classify objects are made available at: .

  8. BeppoSAX observations of 2-Jy lobe-dominated broad-line sources - I. The discovery of a hard X-ray component

    NASA Astrophysics Data System (ADS)

    Padovani, Paolo; Morganti, Raffaella; Siebert, Joachim; Vagnetti, Fausto; Cimatti, Andrea

    1999-04-01

    We present new BeppoSAX LECS, MECS and PDS observations of five lobe-dominated, broad-line active galactic nuclei selected from the 2-Jy sample of southern radio sources. These include three radio quasars and two broad-line radio galaxies. ROSAT PSPC data, available for all the objects, are also used to constrain the spectral shape better in the soft X-ray band. The collected data cover the energy range 0.1 - 10 keV, reaching ~ 50 keV for one source (Pictor A). The main result from the spectral fits is that all sources have a hard X-ray spectrum with energy index alpha_x ~ 0.75 in the 2 - 10 keV range. This is at variance with the situation at lower energies where these sources exhibit steeper spectra. Spectral breaks Delta alpha_x ~ 0.5 at 1 - 2 keV characterize in fact the overall X-ray spectra of our objects. The flat, high-energy slope is very similar to that displayed by flat-spectrum/core-dominated quasars, which suggests that the same emission mechanism (most likely inverse Compton) produces the hard X-ray spectra in both classes. Finally, a (weak) thermal component is also present at low energies in the two broad-line radio galaxies included in our study.

  9. BeppoSAX observations of 2 Jy lobe-dominated broad-line sources: the discovery of a hard X-ray component

    NASA Astrophysics Data System (ADS)

    Morganti, Raffaella; Padovani, Paolo; Siebert, Joachim; Cimatti, Andrea; Tadhunter, Clive N.; Vagnetti, Fausto

    1999-01-01

    We present new BeppoSAX LECS, MECS, and PDS observations of five lobe-dominated, broad-line active galactic nuclei selected from the 2 Jy sample of southern radio sources. These include three radio quasars and two broad-line radio galaxies. ROSAT PSPC data, available for all the objects, are also used to better constrain the spectral shape in the soft X-ray band. The collected data cover the 0.1-10keV energy range, reaching 40keV for one source. Detailed spectral fitting shows that all sources have a flat hard X-ray spectrum with energy index ?x~0.75 in the 2-10keV energy range. This is a new result, which is at variance with the situation at lower energies where these sources exhibit steeper spectra. Spectral breaks ~0.5 at 1-2keV characterize the overall X-ray spectra of our objects. The flat, high-energy slope is very similar to that displayed by flat-spectrum/core-dominated quasars, which suggests that the same emission mechanism (most likely inverse Compton) produces the hard X-ray spectra in both classes. Contrary to the optical evidence for some of our sources, no absorption above the Galactic value is found in our sample. Finally, a (weak) thermal component is also present at low energies in the two broad-line radio galaxies included in our study.

  10. Multiple, independent components of ultraviolet radiation mutagenesis in Escherichia coli K-12 uvrB5.

    PubMed Central

    Smith, K C; Sargentini, N J

    1979-01-01

    Reversion systems involving the lacZ53(amber) and leuB19)missense) mutations were developed to study the mutant frequency response of Escherichia coli K-12 uvrB5 (SR250) to ultraviolet radiation (254 nm). A one-hit mutant frequency response was discernible at ultraviolet radiation fluences below approximately 0.5 J m-2. At higher fluences the overall mutant frequency response could be resolved into one-hit and two-hit components. A new interpretation of the published data on E. coli K-12 indicates that SR250 is not unique in this respect. In addition, the Lac reversion system showed enhanced mutagenesis after ultraviolet radiation fluences of approximately 1 to 3 J m-2, whereas the Leu reversion system did not. We conclude that the complex ultraviolet radiation mutant frequency response curves for E. coli K-12 uvrB5 were the result of three independent mutagenic processes for Lac reversion and two for Leu reversion. PMID:387735

  11. Extension of Compressibility-Route Cubic Equations of State and the Radial Distribution Functions at Contact to Multi-Component Hard-Sphere Mixtures

    NASA Astrophysics Data System (ADS)

    Sun, Jiu-Xun; Jin, Ke; Cai, Ling-Cang; Wu, Qiang

    2014-08-01

    The equation of state (EOS) for hard-sphere fluid derived from compressibility routes of Percus-Yevick theory (PYC) is extended. The two parameters are determined by fitting well-known virial coefficients of pure fluid. The extended cubic EOS can be directly extended to multi-component mixtures, merely demanding the EOS of mixtures also is cubic and combining two physical conditions for the radial distribution functions at contact (RDFC) of mixtures. The calculated virial coefficients of pure fluid and predicted compressibility factors and RDFC for both pure fluid and mixtures are excellent as compared with the simulation data. The values of RDFC for mixtures with extremely large size ratio 10 are far better than the BGHLL expressions in literature.

  12. Very fast X-ray spectral variability in Cygnus X-1: origin of the hard- and soft-state emission components

    NASA Astrophysics Data System (ADS)

    Skipper, Chris J.; McHardy, Ian M.; Maccarone, Thomas J.

    2013-09-01

    The way in which the X-ray photon index, ?, varies as a function of count rate is a strong diagnostic of the emission processes and emission geometry around accreting compact objects. Here we present the results from a study using a new, and simple, method designed to improve sensitivity to the measurement of the variability of ? on very short time-scales. We have measured ? in ˜2 million spectra, extracted from observations with a variety of different accretion rates and spectral states, on time-scales as short as 16 ms for the high-mass X-ray binary Cygnus X-1 (and in a smaller number of spectra for the low-mass X-ray binary GX 339-4), and have cross-correlated these measurements with the source count rate. In the soft-state cross-correlation functions (CCFs), we find a positive peak at zero lag, stronger and narrower in the softer observations. Assuming that the X-rays are produced by Compton scattering of soft seed photons by high-energy electrons in a corona, these results are consistent with Compton cooling of the corona by seed photons from the inner edge of the accretion disc, the truncation radius of which increases with increasing hardness ratio. The CCFs produced from the hard-state observations, however, show an anti-correlation which is most easily explained by variation in the energy of the electrons in the corona rather than in variation of the seed photon flux. The hard-state CCFs can be decomposed into a narrow anti-correlation at zero lag, which we tentatively associate with the effects of self-Comptonization of cyclo-synchrotron seed photons in either a hot, optically thin accretion flow or the base of the jet, and a second, asymmetric component which we suggest is produced as a consequence of a lag between the soft and hard X-ray emission. The lag may be caused by a radial temperature/energy gradient in the Comptonizing electrons combined with the inward propagation of accretion rate perturbations.

  13. Influence of Natural Convection and Thermal Radiation Multi-Component Transport in MOCVD Reactors

    NASA Technical Reports Server (NTRS)

    Lowry, S.; Krishnan, A.; Clark, I.

    1999-01-01

    The influence of Grashof and Reynolds number in Metal Organic Chemical Vapor (MOCVD) reactors is being investigated under a combined empirical/numerical study. As part of that research, the deposition of Indium Phosphide in an MOCVD reactor is modeled using the computational code CFD-ACE. The model includes the effects of convection, conduction, and radiation as well as multi-component diffusion and multi-step surface/gas phase chemistry. The results of the prediction are compared with experimental data for a commercial reactor and analyzed with respect to the model accuracy.

  14. Studies on the immobilization of biofunctional components by radiation polymerization and their applications

    NASA Astrophysics Data System (ADS)

    Kaetsu, Isao; Kumakura, Minoru; Fujimura, Takashi; Yoshida, Masaru; Asano, Masaharu; Kasai, Noboru; Tamada, Masao

    The recent progress on the studies of immobilization of various biofunctional components mainly by mean of radiation polymerization as well as their practical applications to biomedical and biochemical fields were reviewed. The immobilization of drugs for the controlled release and targetting, the immobilization of antigens and antibodies for the immunodiagnosis, and the immobilization of microorganisms and tissue cells for the cell culture and the biomass conversion were the main topics in this review. The new findings on the enhanced immobilization methods and the polymeric carriers for immobilization were also attached.

  15. A review on the effects of ionizing radiation on blood and blood components

    NASA Astrophysics Data System (ADS)

    Jacobs, Geoffrey P.

    1998-11-01

    The major application of blood irradiation is for the prevention of graft-versus-host disease on immunodeficient patients by the abrogation of T-lymphocytes. Despite screening of blood donations, transfusion associated transmission of infections due to contaminated blood products is common. Hence, there is potential for the application of irradiation for the inactivation of pathogenic microbes in blood products. Literature on the effect of radiation on blood components is reviewed in order to make a rational decision on the feasibility of their irradiation.

  16. 3 mm Anisotropy Measurement: On the Quadrupole Component in theCosmic Background Radiation

    SciTech Connect

    Lubin, Philip M.; Epstein, Gerald L.; Smoot, George F.

    1982-11-01

    We have mapped the large-scale anisotropy in the cosmic background radiation at 3 mm wavelength using a liquid-helium-cooled balloon-borne radiometer sensitive enough to detect the dipole in one gondola rotation (1 minute). Statistical errors on the dipole and quadrupole components are below 0.1 mK with less than 0.1 m K galactic contribution. We find a dipole consistent with previous measurements but disagree with recent quadrupole reports. The measurement is also useful in searching for spectral distortions.

  17. Radiation and temperature effects on electronic components investigated under the CSTI High Capacity Power Project

    SciTech Connect

    Shwarze, G.E. [National Aeronautics and Space Administration, Cleveland, OH (United States). Lewis Research Center; Niedra, J.M. [Sverdrup Technology, Inc., Brook Park, OH (United States) Lewis Research Center Group; Frasca, A.J. [Wittenberg Univ., Springfield, OH (United States); Wieserman, W.R. [Univ. of Pittsburgh, Johnstown, PA (United States)

    1994-09-01

    The effects of nuclear radiation and high temperature environments must be fully known and understood for the electronic components and materials used in both the Power Conditioning and Control subsystem and the reactor Instrumentation and Control subsystem of future high capacity nuclear space power systems. This knowledge is required by the designer of these subsystems in order to develop highly reliable, long-life power systems for future NASA missions. A review and summary of the experimental results obtained for the electronic components and materials investigated under the power management element of the CSTI high capacity power project will be presented in this paper: (1) Neutron, gamma ray, and temperature effects on power semiconductor switches, (2) Temperature and frequency effects on soft magnetic materials; and (3) Temperature effects on rare earth permanent magnets.

  18. Radiation and temperature effects on electronic components investigated under the CSTI high capacity power project

    NASA Technical Reports Server (NTRS)

    Schwarze, Gene E.; Niedra, Janis M.; Frasca, Albert J.; Wieserman, William R.

    1993-01-01

    The effects of nuclear radiation and high temperature environments must be fully known and understood for the electronic components and materials used in both the Power Conditioning and Control subsystem and the reactor Instrumentation and Control subsystem of future high capacity nuclear space power systems. This knowledge is required by the designer of these subsystems in order to develop highly reliable, long-life power systems for future NASA missions. A review and summary of the experimental results obtained for the electronic components and materials investigated under the power management element of the Civilian Space Technology Initiative (CSTI) high capacity power project are presented: (1) neutron, gamma ray, and temperature effects on power semiconductor switches, (2) temperature and frequency effects on soft magnetic materials; and (3) temperature effects on rare earth permanent magnets.

  19. Accompanying of parameters of color, gloss and hardness on polymeric films coated with pigmented inks cured by different radiation doses of ultraviolet light

    NASA Astrophysics Data System (ADS)

    Bardi, Marcelo Augusto Gonçalves; Machado, Luci Diva Brocardo

    2012-09-01

    In the search for alternatives to traditional paint systems solvent-based, the curing process of polymer coatings by ultraviolet light (UV) has been widely studied and discussed, especially because of their high content of solids and null emission of VOC. In UV-curing technology, organic solvents are replaced by reactive diluents, such as monomers. This paper aims to investigate variations on color, gloss and hardness of print inks cured by different UV radiation doses. The ratio pigment/clear coating was kept constant. The clear coating presented higher average values for König hardness than pigmented ones, indicating that UV-light absorption has been reduced by the presence of pigments. Besides, they have indicated a slight variation in function of cure degree for the studied radiation doses range. The gloss loss related to UV light exposition allows inferring that some degradation occurred at the surface of print ink films.

  20. Principal Component Analysis and Radiative Transfer modelling of Spitzer IRS Spectra of Ultra Luminous Infrared Galaxies

    E-print Network

    Hurley, Peter D; Farrah, Duncan; Wang, Lingyu; Efstathiou, Andreas

    2012-01-01

    The mid-infrared spectra of ultraluminous infrared galaxies (ULIRGs) contain a variety of spectral features that can be used as diagnostics to characterise the spectra. However, such diagnostics are biased by our prior prejudices on the origin of the features. Moreover, by using only part of the spectrum they do not utilise the full information content of the spectra. Blind statistical techniques such as principal component analysis (PCA) consider the whole spectrum, find correlated features and separate them out into distinct components. We further investigate the principal components (PCs) of ULIRGs derived in Wang et al.(2011). We quantitatively show that five PCs is optimal for describing the IRS spectra. These five components (PC1-PC5) and the mean spectrum provide a template basis set that reproduces spectra of all z<0.35 ULIRGs within the noise. For comparison, the spectra are also modelled with a combination of radiative transfer models of both starbursts and the dusty torus surrounding active gala...

  1. Hubble diagrams of soft and hard radiation sources in the graviton background: to an apparent contradiction between supernova 1a and gamma-ray burst observations

    E-print Network

    Michael A. Ivanov

    2007-01-10

    In the sea of super-strong interacting gravitons, non-forehead collisions with gravitons deflect photons, and this deflection may differ for soft and hard radiations. As a result, the Hubble diagram would not be a universal function and it will have a different view for such sources as supernovae in visible light and gamma-ray bursts. Observations of these two kinds are compared here with the limit cases of the Hubble diagram.

  2. Luminescence properties of a Lu2O3:Eu3+ nano-phosphor and radiation hardness measurements with a proton beam

    NASA Astrophysics Data System (ADS)

    Oh, Myeongjin; Kim, H. J.; Kim, Sunghwan; Cheon, ChongKyu

    2012-07-01

    Eu3+-doped Lu2O3 phosphors typically have an emission wavelength in the red region. The transition of Eu3+ is due to the 5D0 ? 7F2 transition at 610 nm. To produce the Lu2O3:Eu3+ phosphors, we used a co-precipitation method with lutetium nitrate hydrate (Lu(NO3)3·6H2O), europium nitrate hydrate (Eu(NO3)3·6H2O) and diethanolamine (C4H11NO2). The phosphors were sintered at temperatures from 1,100 °C to 1,700 °C by using an electric furnace in an air atmosphere. Then, we obtained the luminescence properties of the phosphors, such as emission and excitation spectra, Field-emission scanning electron microscopy images, X-ray diffraction patterns, radiation hardness, etc. Lu2O3:Eu3+ showed the highest efficiency when sintered at 1,600 °C with a 6%Eu3+ concentration. For the radiation hardness test, a 45-MeV, 10-nA proton beam (MC-50 cyclotron at the KIRMS) was used. Three samples were irradiated with the proton beam: 10, 20, and 40 minutes. The total irradiation dose was approximately 105 ˜ 106 Gy. We did not observe any remarkable changes in the intensity of the luminescence or in the range of the emission wavelength. Hence, we conclude that Lu2O3:Eu3+ phosphors are radiation hard.

  3. Radiation hard vacuum switch

    DOEpatents

    Boettcher, Gordon E. (Albuquerque, NM)

    1990-01-01

    A vacuum switch with an isolated trigger probe which is not directly connected to the switching electrodes. The vacuum switch within the plasmatron is triggered by plasma expansion initiated by the trigger probe which travels through an opening to reach the vacuum switch elements. The plasma arc created is directed by the opening to the space between the anode and cathode of the vacuum switch to cause conduction.

  4. RHOBOT: Radiation hardened robotics

    SciTech Connect

    Bennett, P.C.; Posey, L.D. [Sandia National Labs., Albuquerque, NM (United States)

    1997-10-01

    A survey of robotic applications in radioactive environments has been conducted, and analysis of robotic system components and their response to the varying types and strengths of radiation has been completed. Two specific robotic systems for accident recovery and nuclear fuel movement have been analyzed in detail for radiation hardness. Finally, a general design approach for radiation-hardened robotics systems has been developed and is presented. This report completes this project which was funded under the Laboratory Directed Research and Development program.

  5. Radiation Qualification of Electronics Components used for the ATLAS Level-1 Muon Endcap Trigger System

    E-print Network

    Ichimiya, R; Arai, Y; Ikeno, M; Sasaki, O; Ohshita, H; Takada, N; Hane, Y; Hasuko, K; Nomoto, H; Sakamoto, H; Shibuya, K; Takemoto, T; Fukunaga, C; Toshima, K; Sakuma, T; 2004 IEEE Nuclear Science Symposium And Medical Imaging Conference

    2004-01-01

    The ATLAS end-cap muon level-1 trigger system is divided into three parts; one off-detector part and two on-detector parts. Application specific IC (ASIC) and anti-fuse FPGA (Field Programmable Gate Array) are actively used in on-detector parts. Data transfer with Low-Voltage Data Signaling serial link (LVDS link) is used between two on-detector parts (15m apart) and G-Link (Hewlett-Packard 1.4Gbaud high speed data link) with optical transmission(90m) is used from one of the on-detector parts to the off-detector part. These components will suffer for ten years the radiation of approximately 200Gy of total ionizing dose (TID) and a hadron fluence of 2x10^10 hadrons/c^m2. We have investigated systematically the radiation susceptibility to both total ionizing dose and single event effects for ASIC, FPGA, and Commercial Off The Shelf (COTS) serializer and deserializer chipsets for LVDS (two candidates) and G-Link (one) together. In this presentation we report the result of irradiation tests for these devices and ...

  6. Analysis of Spectroscopic Radiation Portal Monitor Data Using Principal Components Analysis

    SciTech Connect

    Runkle, Robert C.; Tardiff, Mark F.; Anderson, K K.; Carlson, Deborah K.; Smith, L E.

    2006-06-01

    Many international border crossings screen cargo for illicit nuclear material using radiation portal monitors (RPMs) that measure the gamma-ray flux emitted by vehicles. Screening often consists of primary, which acts as a trip-wire for suspect vehicles, and secondary, which locates the radiation source and performs isotopic identification. The authors present a method of anomaly detection for primary screening that uses past observations of gamma-ray signatures to define an expected benign vehicle population. Newly acquired spectra are then compared to this expected population using statistical criteria that reflect acceptable alarm rates and probabilities of detection. Shown here is an analysis of spectroscopic RPM data collected at an international border crossing using this technique. The raw data were analyzed to develop an expected benign vehicle population by decimating the original pulse-height channels, extracting composite variables with principal components analysis, and estimating variance-weighted distances from the ''mean vehicle spectra'' with the Mahalanobis distance metric. The following analysis considers data acquired with both NaI(Tl)-based and plastic scintillator-based RPMs. For each system, performance estimates for anomaly sources are compared to common nuisance sources. The algorithm reported here shows promising results in that it is more sensitive to the anomaly sources than common nuisance sources for both RPM types.

  7. A Principal Component-Based Radiative Transfer Forward Model (PCRTM) for Vertically in Homogeneous Cloud

    NASA Technical Reports Server (NTRS)

    Li, Hui; Liu, Xu; Yang, Ping; Kratz, David P.

    2010-01-01

    A principal-component based radiative transfer model (PCRTM) is developed for simulating the infrared spectral radiance at the top of the atmosphere (TOA). The PCRTM approach removes the redundancy in radiative transfer calculation in high resolution infrared spectra, and saves significant amount of computational time with great accuracy. In PCRTM, both ice and water clouds are treated as effective transmissivity and reflectivity stored in a pre-calculated lookup tables. These quantities are calculated using cloud single scattering properties such as cloud optical depth, cloud particle size, cloud phase, etc. The cloud can be inserted into any pressure layer in the PCRTM model (up to 100 layers). The effective temperature of each cloud layer is treated as a function of its optical depth. To test the accuracy of this approximation, the results are compared with the more rigorous DISORT model, which treats cloud as a plane parallel layer. The root-mean-square error of PCRTM, with respect to DISORT results, is generally less than 0.5 K in brightness temperature. However, the CPU time required by PCRTM was approximately two orders of magnitude less than that required by DISORT.

  8. Holey fibre delivered radiation for laser curing and trimming of direct write components

    NASA Astrophysics Data System (ADS)

    Delmonte, T.; Raja, S.; McDonald, J.; Sidhu, J.; O'Driscoll, E. J.; Flanagan, J. C.; Hayes, J. R.; Petrovich, M. N.; Finazzi, V.; Polletti, F.; Richardson, D. J.; Hand, D. P.

    2006-09-01

    In this paper we demonstrate how Holey Fibre (HF) technology can positively impact the field of materials processing and fabrication, specifically Direct Write (DW). DW is the large scale, patterned deposition of functional materials onto both flat and conformal surfaces. Currently, DW techniques involve thermal post-processing whereby the entire structure is enclosed inside an oven, so limiting the DW technique to small, heat resistant surfaces. Selectively laser curing the ink would allow the ink to be brought up to the required temperature without heating the surrounding substrate material. In addition the ability to trim components would allow miniature circuits to be written and devices to be tuned by changing the capacitance or resistance. HF technology enables in-situ curing and trimming of direct write components using the same rig and length of fibre. HF's with mode areas in excess of 450?m2 can be routinely fabricated allowing high power transmission whilst retaining the high beam quality of the radiation source. We will present results of curing and trimming trials which demonstrate that HF's provide a distinct advantage over standard multimode fibres by allowing both curing and machining to be achieved through a single delivery fibre.

  9. Radiation damage and repair in cells and cell components. Part 2. Physical radiations and biological significance. Final report

    SciTech Connect

    Fluke, D.J.

    1984-08-01

    The report comprises a teaching text, encompassing all physical radiations likely to be of biological interest, and the relevant biological effects and their significance. Topics include human radiobiology, delayed effects, radiation absorption in organisms, aqueous radiation chemistry, cell radiobiology, mutagenesis, and photobiology. (ACR)

  10. Radiation hardness of passive fibre optic components for the future thermo-nuclear fusion reactor instrumentation links

    Microsoft Academic Search

    A. Fernandez Fernandez

    2001-01-01

    Abstract: thermon uclearfusionreactor ITER will requireremote-hanA#0 equipment to monNNfl itsoperation anto allow hazard-freemand-freexAN durinitsfrequen tmain ten3#periods. Heavy shielded umbilicals willbe required tocon5N3 thesen2A5 an the actuators with theirinrx0flNj tationMultiplexinsen#0 signfl3turn out tobeessential to ease the umbilicalmancalx5 t. Wearecon33NxF0#fibre optic technxfljN , with itsintrinfl#wavelenflfl multiplexin(WDM) capabilities, tohanA5 these ITERmultiplexin...

  11. Status of the hard X-ray microprobe beamline ID22 of the European Synchrotron Radiation Facility.

    PubMed

    Martínez-Criado, Gema; Tucoulou, Rémi; Cloetens, Peter; Bleuet, Pierre; Bohic, Sylvain; Cauzid, Jean; Kieffer, Isabelle; Kosior, Ewelina; Labouré, Sylvain; Petitgirard, Sylvain; Rack, Alexander; Sans, Juan Angel; Segura-Ruiz, Jaime; Suhonen, Heikki; Susini, Jean; Villanova, Julie

    2012-01-01

    The ESRF synchrotron beamline ID22, dedicated to hard X-ray microanalysis and consisting of the combination of X-ray fluorescence, X-ray absorption spectroscopy, diffraction and 2D/3D X-ray imaging techniques, is one of the most versatile instruments in hard X-ray microscopy science. This paper describes the present beamline characteristics, recent technical developments, as well as a few scientific examples from recent years of the beamline operation. The upgrade plans to adapt the beamline to the growing needs of the user community are briefly discussed. PMID:22186639

  12. A pixel unit-cell targeting 16 ns resolution and radiation hardness in a column read-out particle vertex detector

    SciTech Connect

    Wright, M.; Millaud, J.; Nygren, D.

    1992-10-01

    A pixel unit cell (PUC) circuit architecture, optimized for a column read out architecture, is reported. Each PUC contains an integrator, active filter, comparator, and optional analog store. The time-over-threshold (TOT) discriminator allows an all-digital interface to the array periphery readout while passing an analog measure of collected charge. Use of (existing) radiation hard processes, to build a detector bump-bonded to a pixel readout array, is targeted. Here, emphasis is on a qualitative explanation of how the unique circuit implementation benefits operation for Super Collider (SSC) detector application.

  13. The radiative-adiabatic model of 2-component (2 + 2) greenhouse effect is applicable for wide range of planetary environment

    Microsoft Academic Search

    A. V. Karnaukhov

    2004-01-01

    In earlier works (1) it is shown that the radiative-adiabatic model make it possible the analytical solution for the 2-component (2 + 2) greenhouse effect in the case of the optical dense atmosphere (Earth, Venus). Now we have obtained the analytical estimation of greenhouse effect not only for the planets with the high optical density of atmosphere but also for

  14. Total-dose radiation effects data for semiconductor devices, volume 1. [radiation resistance of components for the Galileo Project

    NASA Technical Reports Server (NTRS)

    Price, W. E.; Martin, K. E.; Nichols, D. K.; Gauthier, M. K.; Brown, S. F.

    1981-01-01

    Steady-state, total-dose radiation test data are provided in graphic format, for use by electronic designers and other personnel using semiconductor devices in a radiation environment. Data are presented by JPL for various NASA space programs on diodes, bipolar transistors, field effect transistors, silicon-controlled rectifiers, and optical devices. A vendor identification code list is included along with semiconductor device electrical parameter symbols and abbreviations.

  15. A delay-efficient radiation-hard digital design approach using code word state preserving (cwsp) elements

    E-print Network

    Nagpal, Charu

    2008-10-10

    With the relentless shrinking of the minimum feature size of VLSI Integrated Circuits (ICs), reduction in operating voltages and increase in operating frequencies, VLSI circuits are becoming more vulnerable to radiation strikes. As a result...

  16. The hard metal diseases

    SciTech Connect

    Cugell, D.W. (Department of Medicine, Northwestern University Medical School, Chicago, IL (United States))

    1992-06-01

    Hard metal is a mixture of tungsten carbide and cobalt, to which small amounts of other metals may be added. It is widely used for industrial purposes whenever extreme hardness and high temperature resistance are needed, such as for cutting tools, oil well drilling bits, and jet engine exhaust ports. Cobalt is the component of hard metal that can be a health hazard. Respiratory diseases occur in workers exposed to cobalt--either in the production of hard metal, from machining hard metal parts, or from other sources. Adverse pulmonary reactions include asthma, hypersensitivity pneumonitis, and interstitial fibrosis. A peculiar, almost unique form of lung fibrosis, giant cell interstitial pneumonia, is closely linked with cobalt exposure.66 references.

  17. Fermi Observations of GRB 090510: A Short-Hard Gamma-ray Burst with an Additional, Hard Power-law Component from 10 keV TO GeV Energies

    Microsoft Academic Search

    M. Ackermann; K. Asano; W. B. Atwood; M. Axelsson; L. Baldini; J. Ballet; G. Barbiellini; M. G. Baring; D. Bastieri; K. Bechtol; R. Bellazzini; B. Berenji; P. N. Bhat; E. Bissaldi; R. D. Blandford; E. D. Bloom; E. Bonamente; A. W. Borgland; A. Bouvier; J. Bregeon; A. Brez; M. S. Briggs; M. Brigida; P. Bruel; S. Buson; G. A. Caliandro; R. A. Cameron; P. A. Caraveo; S. Carrigan; J. M. Casandjian; C. Cecchi; Ö. Çelik; E. Charles; J. Chiang; S. Ciprini; R. Claus; J. Cohen-Tanugi; V. Connaughton; J. Conrad; C. D. Dermer; F. de Palma; B. L. Dingus; E. do Couto e. Silva; P. S. Drell; R. Dubois; D. Dumora; C. Farnier; C. Favuzzi; S. J. Fegan; J. Finke; W. B. Focke; M. Frailis; Y. Fukazawa; P. Fusco; F. Gargano; D. Gasparrini; N. Gehrels; S. Germani; N. Giglietto; F. Giordano; T. Glanzman; G. Godfrey; J. Granot; I. A. Grenier; M.-H. Grondin; J. E. Grove; S. Guiriec; D. Hadasch; A. K. Harding; E. Hays; D. Horan; R. E. Hughes; G. Jóhannesson; W. N. Johnson; T. Kamae; H. Katagiri; J. Kataoka; N. Kawai; R. M. Kippen; J. Knödlseder; D. Kocevski; C. Kouveliotou; M. Kuss; J. Lande; L. Latronico; M. Lemoine-Goumard; M. Llena Garde; F. Longo; F. Loparco; B. Lott; M. N. Lovellette; P. Lubrano; A. Makeev; M. N. Mazziotta; J. E. McEnery; S. McGlynn; C. Meegan; P. Mészáros; P. F. Michelson; W. Mitthumsiri; T. Mizuno; A. A. Moiseev; C. Monte; M. E. Monzani; E. Moretti; A. Morselli; I. V. Moskalenko; S. Murgia; H. Nakajima; T. Nakamori; P. L. Nolan; J. P. Norris; E. Nuss; M. Ohno; T. Ohsugi; N. Omodei; E. Orlando; J. F. Ormes; M. Ozaki; W. S. Paciesas; D. Paneque; J. H. Panetta; D. Parent; V. Pelassa; M. Pepe; M. Pesce-Rollins; F. Piron; R. Preece; S. Rainò; R. Rando; M. Razzano; S. Razzaque; A. Reimer; S. Ritz; A. Y. Rodriguez; M. Roth; F. Ryde; H. F.-W. Sadrozinski; A. Sander; J. D. Scargle; T. L. Schalk; C. Sgrò; E. J. Siskind; P. D. Smith; G. Spandre; P. Spinelli; M. Stamatikos; F. W. Stecker; M. S. Strickman; D. J. Suson; H. Tajima; H. Takahashi; T. Takahashi; T. Tanaka; J. B. Thayer; J. G. Thayer; D. J. Thompson; L. Tibaldo; K. Toma; D. F. Torres; G. Tosti; A. Tramacere; Y. Uchiyama; T. Uehara; T. L. Usher; A. J. van der Horst; V. Vasileiou; N. Vilchez; V. Vitale; A. von Kienlin; A. P. Waite; P. Wang; C. Wilson-Hodge; B. L. Winer; X. F. Wu; R. Yamazaki; Z. Yang; T. Ylinen; M. Ziegler

    2010-01-01

    We present detailed observations of the bright short-hard gamma-ray burst GRB 090510 made with the Gamma-ray Burst Monitor (GBM) and Large Area Telescope (LAT) on board the Fermi observatory. GRB 090510 is the first burst detected by the LAT that shows strong evidence for a deviation from a Band spectral fitting function during the prompt emission phase. The time-integrated spectrum

  18. Prevention of ultraviolet radiation-induced suppression of accessory cell function of Langerhans cells by Aloe vera gel components.

    PubMed

    Lee, C K; Han, S S; Mo, Y K; Kim, R S; Chung, M H; Park, Y I; Lee, S K; Kim, Y S

    1997-10-01

    The active components of Aloe vera gel that can prevent ultraviolet B (UVB)-induced suppression of accessory cell function of Langerhans cells (LC) were purified by activity-guided sequential fractionation followed by in vitro functional assay. The functional assay was based on the fact that exposure of freshly isolated murine epidermal cells (EC) to UVB radiation resulted in impairment of accessory cell function of LC, as measured by their ability to support anti-CD3 monoclonal antibody (mAb)-primed T-cell mitogenesis. This UVB-suppressed LC accessory cell function was prevented by addition of partially purified Aloe gel components to cultures of UVB-irradiated EC. The Aloe gel components appeared to prevent events occurring within the first 24 h after UVB irradiation that lead to the impairment of accessory cell function. The Aloe gel components did not cause proliferation of anti-CD3 mAb-primed T-cells, nor did induce proliferation of normal EC. The activity-guided final purification of Aloe gel components resulted in the isolation of two components. Both of the components were small molecular weight (MW) substances with an apparent MW of less than 1,000 Da but different from each other in net charge characteristics at pH 7.4. These results suggest that Aloe vera gel contains at least two small molecular weight immunomodulators that may prevent UVB-induced immune suppression in the skin. PMID:9403333

  19. Characterization and Application of Hard X-Ray Betatron Radiation Generated by Relativistic Electrons from a Laser-Wakefield Accelerator

    E-print Network

    Schnell, Michael; Uschmann, Ingo; Jansen, Oliver; Kaluza, Malte Christoph; Spielmann, Christian

    2015-01-01

    The necessity for compact table-top x-ray sources with higher brightness, shorter wavelength and shorter pulse duration has led to the development of complementary sources based on laser-plasma accelerators, in contrast to conventional accelerators. Relativistic interaction of short-pulse lasers with underdense plasmas results in acceleration of electrons and in consequence in the emission of spatially coherent radiation, which is known in the literature as betatron radiation. In this article we report on our recent results in the rapidly developing field of secondary x-ray radiation generated by high-energy electron pulses. The betatron radiation is characterized with a novel setup allowing to measure the energy, the spatial energy distribution in the far-field of the beam and the source size in a single laser shot. Furthermore, the polarization state is measured for each laser shot. In this way the emitted betatron x-rays can be used as a non-invasive diagnostic tool to retrieve very subtle information of t...

  20. Gizzard and other lean mass components increase, yet Basal Metabolic Rates decrease, when red knots Calidris canutus are shifted from soft to hard-shelled food

    Microsoft Academic Search

    Theunis Piersma; James A. Gessaman; Anne Dekinga; G. Henk Visser

    2004-01-01

    We measured basal metabolic rate (BMR), body mass, lean mass, and gizzard mass of captive red knots Calidris canutus islandica maintained on a trout chow diet (soft- texture, low ash and water content) for several years and then shifted to small mussels Mytilus edulis (hard-texture, high ash and water content). During a 3-week period of feeding on mussels, body mass,

  1. Metal/ceramic composite heat pipes for a low-mass, intrinsically-hard 875 K radiator. [Ti

    SciTech Connect

    Rosenfeld, J.H.; Ernst, D.M. (Thermacore, Inc., 780 Eden Road, Lancaster, Pennsylvania (USA)); Nardone, V.C. (United Technologies Research Center, Silver Lane, MS 13, East Hartford, Connecticut (USA))

    1991-01-10

    Thermacore, Inc. of Lancaster, Pennsylvania has recently completed Phase I of a development program to investigate the use of layered metal/ceramic composites in the design of low-mass hardened radiators for space heat rejection systems. This effort evaluated the use of layered composites as a material to form thin-walled, vacuum leaktight heat pipes. The heat pipes would be incorporated into a large heat pipe radiator for waste heat rejection from a space nuclear power source. This approach forms an attractive alternative to carbon/carbon, or silicon-carbide fiber reinforced metal heat pipes by offering a combination of low mass and improved fabricability. Thermacore and United Technologies Research Center have jointly developed an approach for fabrication of layered composite thin-walled heat pipes for use in hardened space radiators. Potassium heat pipes with wall thicknesses as low a 0.3 mm have been built and tested. Wall thicknesses as low as 0.13 mm are believed to be achievable with this approach.

  2. Study of the ratio of non-neutron to neutron dose components of cosmic radiation at typical commercial flight altitudes.

    PubMed

    Romero, A M; Saez-Vergara, J C; Rodriguez, R; Domínguez-Mompell, R

    2004-01-01

    CIEMAT, in close co-operation with Iberia Airlines, carried out an extensive programme of in-flight measurements, covering both hemispheres, during the years 2001 and 2002. Although the instrumentation onboard included different active devices, the results presented here were obtained from a polyethylene/tungsten-moderated rem meter (SWENDI2; Eberline) and an ionisation chamber (RSS-131; Reuter-Stokes) used for measuring the ambient dose equivalent due to the neutron and the non-neutron components of cosmic radiation, respectively. This paper presents a study of each of the dose components mentioned as a function of the vertical cut-off rigidity and the flight altitude. The ratio between the two components is also presented to determine the variations in cosmic radiation composition as a function of the aforementioned parameters. The experimental results have also been compared with those predicted by the code EPCARD3.2 for the non-neutron and the neutron components of the ambient dose equivalent. PMID:15353674

  3. Photosynthetically active components of global solar radiation: Measurements and model computations

    Microsoft Academic Search

    C. R. Nagaraja Rao

    1984-01-01

    Summary  A three-year(1980–82) record of global solar radiation measurements made at Corvallis, Oregon, U.S.A. (44°34N, 123°14W; 65.5 m) has been utilized to determine the distribution of radiant energy in broad spectral intervals in the visible (0.385–0.695 m) region of the spectrum which is often referred to as the photosynthetically active radiation or PAR band. The mean values of the ratios borne

  4. On the Radiating and Nonradiating Components of Scalar, Electromagnetic, and Weak Gravitational Sources

    Microsoft Academic Search

    Edwin A. Marengo; Richard W. Ziolkowski

    1999-01-01

    We derive a new description of two complementary classes of scalar, vector, or tensor sources, namely, nonradiating (NR) sources and sources that lack a NR part, i.e., ``purely radiating'' sources. The class of purely radiating sources is shown to be exactly the class of solutions-within the source's support-of the homogeneous form of the associated partial differential equation relating the sources

  5. Impact of Bone Marrow Radiation Dose on Acute Hematologic Toxicity in Cervical Cancer: Principal Component Analysis on High Dimensional Data

    SciTech Connect

    Yun Liang [Department of Radiation Oncology, Center for Advanced Radiotherapy Technologies, University of California San Diego, La Jolla, California (United States); Messer, Karen [Division of Biostatistics and Bioinformatics, Moores Cancer Center, University of California San Diego, La Jolla, California (United States); Rose, Brent S.; Lewis, John H.; Jiang, Steve B.; Yashar, Catheryn M.; Mundt, Arno J. [Department of Radiation Oncology, Center for Advanced Radiotherapy Technologies, University of California San Diego, La Jolla, California (United States); Mell, Loren K., E-mail: lmell@ucsd.ed [Department of Radiation Oncology, Center for Advanced Radiotherapy Technologies, University of California San Diego, La Jolla, California (United States)

    2010-11-01

    Purpose: To study the effects of increasing pelvic bone marrow (BM) radiation dose on acute hematologic toxicity in patients undergoing chemoradiotherapy, using a novel modeling approach to preserve the local spatial dose information. Methods and Materials: The study included 37 cervical cancer patients treated with concurrent weekly cisplatin and pelvic radiation therapy. The white blood cell count nadir during treatment was used as the indicator for acute hematologic toxicity. Pelvic BM radiation dose distributions were standardized across patients by registering the pelvic BM volumes to a common template, followed by dose remapping using deformable image registration, resulting in a dose array. Principal component (PC) analysis was applied to the dose array, and the significant eigenvectors were identified by linear regression on the PCs. The coefficients for PC regression and significant eigenvectors were represented in three dimensions to identify critical BM subregions where dose accumulation is associated with hematologic toxicity. Results: We identified five PCs associated with acute hematologic toxicity. PC analysis regression modeling explained a high proportion of the variation in acute hematologicity (adjusted R{sup 2}, 0.49). Three-dimensional rendering of a linear combination of the significant eigenvectors revealed patterns consistent with anatomical distributions of hematopoietically active BM. Conclusions: We have developed a novel approach that preserves spatial dose information to model effects of radiation dose on toxicity, which may be useful in optimizing radiation techniques to avoid critical subregions of normal tissues. Further validation of this approach in a large cohort is ongoing.

  6. High-performance wear-resistant ion-plasma coatings based on five-component nitrides for a hard-alloy cutting tool operating under constant loads

    Microsoft Academic Search

    A. O. Volkhonskii; I. V. Blinkov; A. V. Elyutin; O. B. Podstyazhonok

    2010-01-01

    Studies are made of multicomponent coatings obtained in the system Ti–Al–Cr–Zr–Nb–N by the Arc-PVD method on vacuum-type ion-plasma\\u000a unit Bulat – NNV 6.6-I1. The coatings were obtained in a medium of reactive gaseous nitrogen. The study results showed that\\u000a the coatings exhibit high values for hardness and durability when used under continuous cutting conditions.

  7. New types of multi-component hard coatings deposited by ARC PVD on steel pre-treated by pulsed plasma beams

    Microsoft Academic Search

    Z. Werner; J. Stanis?awski; J. Piekoszewski; E. A. Levashov; W Szymczyk

    2003-01-01

    The paper presents the results of experiments on depositing of the multicomponent Ti–B–N, Ti–Si–N, and Ti–B–Si–N coatings on HSS steel using the ARC PVD technique in a novel two-step approach with the plasma pulse pretreatment. The coatings were characterized by X-ray diffraction and tribological tests (nanohardness measurements, scratch tests, wear resistance). The Ti–B–N coatings showed the highest values of hardness,

  8. Radiation damage and repair in cells and cell components. Radiation-induced repair. Progress report, 1981-1982

    SciTech Connect

    Not Available

    1982-01-01

    Progress in research on the description and interpretation of radiation-induced repair in cells is reported. It has been found that for the p-recA data induction seems to follow a model of fractional site occupancy rather than being all-or-none. Other areas investigated include: (1) the induction of the RecA-gene product; (2) the effect of uv-phage lambda infection on Rec-A protein synthesis; (3) induced uv radioresistance; (4) cold-shock effects; (5) lambda-prophage induction by x-rays and uv; (6) photoreactivation of uv-induced dimers; and (7) a comparative study of S.O.S. phenomena in various strains of E. coli. (ACR)

  9. Fusion Reactor Materials and Components: Issues Related to Radioactivity and Radiation-Induced Effects

    SciTech Connect

    Rubel, M

    2004-03-15

    A concise overview is given on materials applied in fusion technology. The influence of plasma operation on the behaviour of reactor components and diagnostic systems is discussed with emphasis on effects caused by fast particles reaching the reactor wall. Issues related to primary and induced radioactivity are reviewed: tritium inventory and transmutation. Tritium breeding in the reactor blanket, separation of hydrogen isotopes and safety aspects in handling radio-contaminated components are also addressed.

  10. A position sensitive highly radiation hard and fast hadron calorimeter for a lead ion experiment at CERN SPS

    NASA Astrophysics Data System (ADS)

    Chiavassa, E.; Dellacasa, G.; De Marco, N.; Gallio, M.; Guaita, P.; Musso, A.; Piccotti, A.; Scomparin, E.; Vercellin, E.

    1995-12-01

    We present the performance of the Zero Degree Calorimeter (ZDC) built for the NA50 experiment at the CERN SPS. This detector measures the Cherenkov light produced in silica optical fibres embedded in tantalum and offers the double advantage of being highly radiation resistant (up to several Grad) and very fast (signal width of the order of 10 ns). It has an active volume of 5 × 5 × 65 cm 3 with a fibre to tantalum volume ratio of {1}/{17}; the fibres are positioned at an angle of 0° with respect to the beam direction and have a diameter of 365 ?m. The measured energy resolution ( {?}/{E}) is 30% for protons at 205 GeV and 5% for lead ions at 160 GeV/nucleon. The detector exhibits also very good localising properties since it can detect the impact point of the lead beam on its front face with a precision better than 0.4 mm rms.

  11. The effect of hard/soft segment composition on radiation stability of poly(ester-urethane)s

    NASA Astrophysics Data System (ADS)

    Walo, Marta; Przybytniak, Gra?yna; ?yczko, Krzysztof; Pi?tek-Hnat, Marta

    2014-01-01

    In this paper studies on the structures and radiation stability of four poly(ester-urethane)s (PUR)s synthesized from oligo(ethylene-butylene adipate)diol of various molecular weights and isophorone diisocyanate/1,4-butanediol are reported. PURs with 40 and 60 wt% soft segments were irradiated at ambient temperature with a high energy electron beam to a dose of 112 kGy. The effect of different segmental compositions on thermal and mechanical properties of polyurethanes, both before and after irradiation, were investigated using mechanical testing and dynamic mechanical thermal analysis. ATR-FTIR spectroscopy was used to study the progress of polycondensation, structure of synthesized polymers and extent of phase separation were determined on a basis of the contribution of hydrogen bonding in poly(ester-urethane)s. Correlation between degree of phase separation and mechanical and thermal properties of poly(ester-urethane)s was found.

  12. Solar heating system, and improved heat collecting and radiating components, for livestock-confining buildings

    Microsoft Academic Search

    1983-01-01

    A system is disclosed for heating a building adapted to confine animals includes a solar collector, means for storing the heat absorbed by the collector and heat radiating floor mats which use such heat. The collector includes panels each having lightweight, clear, parallel plastic tubes secured at their ends to headers of similar material. The tubes are disposed in troughs

  13. Solar heating system, and improved heat collecting and radiating components, for livestock-confining buildings

    Microsoft Academic Search

    1984-01-01

    A system for heating a building adapted to confine animals includes a solar collector, means for storing the heat absorbed by the collector and heat radiating floor mats which use such heat. The collector includes panels each having lightweight, clear, parallel plastic tubes secured at their ends to headers of similar material. The tubes are disposed in troughs in the

  14. Nimbus-6 and -7 Earth Radiation Budget (ERB) sensor details and component tests

    NASA Technical Reports Server (NTRS)

    Soule, H. V.; Kyle, H. L.; Jacobowitz, H.; Hickey, J.

    1983-01-01

    Construction details and operating characteristics are described for the thermopile (used in the solar and fixed-Earth channels) and the pyroelectric detector (used in the Earth-scanning channels) carried on the Nimbus 6 and the Nimbus 7 satellites for gathering Earth radiation budget data. Properties of the black coating for the detectors, and sensor testing and calibration are discussed.

  15. Metabolomics-based component profiling of hard and semi-hard natural cheeses with gas chromatography/time-of-flight-mass spectrometry, and its application to sensory predictive modeling.

    PubMed

    Ochi, Hiroshi; Naito, Hiroshige; Iwatsuki, Keiji; Bamba, Takeshi; Fukusaki, Eiichiro

    2012-06-01

    Gas chromatography/time-of-flight mass spectrometry (GC/TOF-MS) was used to analyze hydrophilic low molecular weight components, including amino acids, fatty acids, amines, organic acids, and saccharides, in cheese, and the sensometric application for practical metabolomic studies in the food industry is described. Derivatization of target analytes was conducted prior to the GC/TOF-MS analysis. Data on 13 cheeses, six Cheddar cheeses, six Gouda cheeses and one Parmigiano-Reggiano cheese, were analyzed by multivariate analysis. The uniqueness of the Parmigiano-Reggiano cheese metabolome was revealed. Principal component analysis (PCA) showed no grouping of the Cheddar cheeses and Gouda cheeses according to production method or country of origin. The PCA loading plot confirms that many amino acids contribute positively to PC1, suggesting that PC1 is closely related to degradation of proteins, and that lactic acid contributed positively to PC2, whereas glycerol contributed negatively to PC2, suggesting that factors regarding degradation of carbohydrates and fats were expressed in PC2. Partial least squares (PLS) regression models were constructed to predict the relationship between the metabolite profile and two sensory attributes, "Rich flavor" and "Sour flavor", which were related to maturation. The compounds that play an important role in constructing each sensory prediction model were identified as 12 amino acids and lactose for "Rich flavor", and 4-aminobutyric acid, ornithine, succinic acid, lactic acid, proline and lactose for "Sour flavor". The present study revealed that metabolomics-based component profiling, focusing on hydrophilic low molecular weight components, was able to predict the sensory characteristics related to ripening. PMID:22386562

  16. Measurements of the high energy neutron component of cosmic radiation fields in aircraft using etched track dosemeters.

    PubMed

    Bartlett, D T; Hager, L G; Tanner, R J; Steele, J D

    2001-06-01

    Measurements of the complex cosmic radiation field in aircraft at altitude are made with a passive survey meter comprising routine-use thermoluminescent detectors and etched track detectors. The energy dependence of response of the etched track detectors used to determine the neutron component has been characterized, partly, up to a neutron energy of 180 MeV. The neutron detectors are routinely calibrated in the CERN/EC Reference Field. The 15% determination level for total dose equivalent is 100 microSv. The evidence is that the passive survey meter provides a reliable determination of route dose. PMID:11852944

  17. Diagnostic components in harsh radiation environments: possible overlap in R&D requirements of inertial confinement and magnetic fusion systems.

    PubMed

    Bourgade, J L; Costley, A E; Reichle, R; Hodgson, E R; Hsing, W; Glebov, V; Decreton, M; Leeper, R; Leray, J L; Dentan, M; Hutter, T; Moroño, A; Eder, D; Shmayda, W; Brichard, B; Baggio, J; Bertalot, L; Vayakis, G; Moran, M; Sangster, T C; Vermeeren, L; Stoeckl, C; Girard, S; Pien, G

    2008-10-01

    The next generation of large scale fusion devices--ITER/LMJ/NIF--will require diagnostic components to operate in environments far more severe than those encountered in present facilities. This harsh environment is the result of high fluxes of neutrons, gamma rays, energetic ions, electromagnetic radiation, and in some cases, debris and shrapnel, at levels several orders of magnitude higher than those experienced in today's devices. The similarities and dissimilarities between environmental effects on diagnostic components for the inertial confinement and magnetic confinement fusion fields have been assessed. Areas in which considerable overlap have been identified are optical transmission materials and optical fibers in particular, neutron detection systems and electronics needs. Although both fields extensively use cables in the hostile environment, there is little overlap because the environments and requirements are very different. PMID:19044617

  18. Prevention of ultraviolet radiation-induced suppression of contact hypersensitivity by Aloe vera gel components

    Microsoft Academic Search

    Chong Kil Lee; Seong Sun Han; Young Keun Shin; Myung Hee Chung; Young In Park; Seung Ki Lee; Yeong Shik Kim

    1999-01-01

    We have recently reported that Aloe vera gel contains small molecular weight immunomodulators, G1C2F1, that restore ultraviolet B (UVB)-suppressed accessory cell function of epidermal Langerhans cells (LC) in vitro. In the present study we evaluated the UVB-protective activity of G1C2F1 in vivo. Exposure of the shaved abdominal skin of mice to 2.4 KJ\\/m2 of UVB radiation resulted in suppression of contact

  19. Assessment of the Water Quality Components in Turbid Estuarine Waters Based on Radiative Transfer Approximations

    EPA Science Inventory

    Bio-geo-optical data collected in the Neuse River Estuary, North Carolina, USA were used to develop a semi-empirical optical algorithm for assessing inherent optical properties associated with water quality components (WQCs). Three wavelengths (560, 665 and 709 nm) were explored ...

  20. Modeling dust as component minerals in the Community Atmosphere Model: development of framework and impact on radiative forcing

    NASA Astrophysics Data System (ADS)

    Scanza, R. A.; Mahowald, N.; Ghan, S.; Zender, C. S.; Kok, J. F.; Liu, X.; Zhang, Y.; Albani, S.

    2015-01-01

    The mineralogy of desert dust is important due to its effect on radiation, clouds and biogeochemical cycling of trace nutrients. This study presents the simulation of dust radiative forcing as a function of both mineral composition and size at the global scale, using mineral soil maps for estimating emissions. Externally mixed mineral aerosols in the bulk aerosol module in the Community Atmosphere Model version 4 (CAM4) and internally mixed mineral aerosols in the modal aerosol module in the Community Atmosphere Model version 5.1 (CAM5) embedded in the Community Earth System Model version 1.0.5 (CESM) are speciated into common mineral components in place of total dust. The simulations with mineralogy are compared to available observations of mineral atmospheric distribution and deposition along with observations of clear-sky radiative forcing efficiency. Based on these simulations, we estimate the all-sky direct radiative forcing at the top of the atmosphere as + 0.05 Wm-2 for both CAM4 and CAM5 simulations with mineralogy. We compare this to the radiative forcing from simulations of dust in release versions of CAM4 and CAM5 (+0.08 and +0.17 Wm-2) and of dust with optimized optical properties, wet scavenging and particle size distribution in CAM4 and CAM5, -0.05 and -0.17 Wm-2, respectively. The ability to correctly include the mineralogy of dust in climate models is hindered by its spatial and temporal variability as well as insufficient global in situ observations, incomplete and uncertain source mineralogies and the uncertainties associated with data retrieved from remote sensing methods.

  1. Investigation on the long-term radiation hardness of low resistivity starting silicon materials for RT silicon detectors in high energy physics

    SciTech Connect

    Li, Z.

    1994-02-01

    Relatively low resistivity (200 to 1000 {Omega}-cm) starting silicon materials have been studied in the search of room temperature neutron radiation-hard silicon detectors. It has been found that, moderate resistivity (300-700 {Omega}-cm) silicon detectors, after being irradiated to 5.0 {times} 10{sup 13} to 2.0 {times} 10{sup 14} n/cm{sup 2}, are extremely stable in terms of the detector full depletion voltage (V{sub d}) or the net effective concentration of ionized space charges (N{sub eff} ---- there is little ``reverse annealing`` of N{sub eff} at RT and elevated temperatures as compared with large reverse annealing observed for high resistivity silicon detectors. Detectors with starting resistivity of 300-700 {Omega}-cm have been found to be stable, during the equivalent of one year RT anneal that would reach the saturation of the first stage of reverse anneal, within then N{sub eff} window of {vert_bar}N{sub eff}{vert_bar}{le} 2.5 {times} 10{sup 12} cm{sup {minus}3} (V{sub d} = 180 V for d = 300 {mu}m) in a working range of 5.0 {times} 10{sup 13} to 1.5 {times} 10{sup 14} n/cm{sup 2}, or a net neutron radiation tolerance of 1.0 {times} 10{sup 14} n/cm{sup 2}. The observed effects are in very good agreement with an early proposed model, which predicted among others, that there might be an off set between the reverse annealing effect and the partial annealing of the P-V centers that leads to the partial recovery of the shallow impurity donors.

  2. Analysis of radiation risk from alpha particle component of solar particle events

    NASA Technical Reports Server (NTRS)

    Cucinotta, F. A.; Townsend, L. W.; Wilson, J. W.; Golightly, M. J.; Weyland, M.

    1994-01-01

    The solar particle events (SPE) will contain a primary alpha particle component, representing a possible increase in the potential risk to astronauts during an SPE over the often studied proton component. We discuss the physical interactions of alpha particles important in describing the transport of these particles through spacecraft and body shielding. Models of light ion reactions are presented and their effects on energy and linear energy transfer (LET) spectra in shielding discussed. We present predictions of particle spectra, dose, and dose equivalent in organs of interest for SPE spectra typical of those occurring in recent solar cycles. The large events of solar cycle 19 are found to have substantial increase in biological risk from alpha particles, including a large increase in secondary neutron production from alpha particle breakup.

  3. Analysis of radiation risk from alpha particle component of soalr particle events

    NASA Technical Reports Server (NTRS)

    Cucinotta, F. A.; Townsend, L. W.; Wilson, J. W.; Golightly, M. J.; Weyland, M.

    1994-01-01

    The Solar Particle Events (SPE) will contain a primary alpha particle component, representing a possible increase in the potential risk to astronauts during an SPE over the often studied proton component. We discuss the physical interactions of alpha particles important in describing the transport of these particles through spacecraft and body shielding. Models of light ion reactions are presented and their effects on energy and Linear Energy Transfer (LET) spectra in shielding are discussed. We present predictions of particle spectra, dose, and dose equivalent in organs of interest for SPE spectra typical of those occurring in recent solar cycles. The large events of solar cycle 19 are found to have substantial increase in biological risk from alpha particles, including a large increase in secondary neutron production from alpha particle breakup.

  4. The magnetic, basal, and radiative-equilibrium components in Mount Wilson Ca II H + K fluxes

    SciTech Connect

    Schrijver, C.J.; Dobson, A.K.; Radick, R.R. (National Solar Observatory, Sunspot, NM (USA); Joint Institute for Laboratory Astrophysics, Boulder, CO (USA))

    1989-06-01

    Mount Wilson Ca II H + K flux measurements of cool dwarf stars are analyzed and compared with stellar Mg II h + k fluxes, variability amplitudes, rotation rates, and solar data. It is concluded that the Mount Wilson Ca II H + K fluxes comprise three principal parts: (1) a photospheric contribution in the line wings, (2) a basal chromospheric component that appears to be unrelated to stellar magnetic activity and is, therefore, possibly nonmagnetic in origin, and (3) a chromospheric component which is associated with magnetically active regions and the (quiet and active) network. The basal chromosphere appears to cover the entire surface of magnetically inactive stars. The basal Ca II H + K flux density for solar-type stars equals the average emission observed in the centers of solar supergranulation cells, where the magnetic flux density is small. 27 refs.

  5. The magnetic, basal, and radiative-equilibrium components in Mount Wilson Ca II H + K fluxes

    NASA Technical Reports Server (NTRS)

    Schrijver, C. J.; Dobson, Andrea K.; Radick, Richard R.

    1989-01-01

    Mount Wilson Ca II H + K flux measurements of cool dwarf stars are analyzed and compared with stellar Mg II h + k fluxes, variability amplitudes, rotation rates, and solar data. It is concluded that the Mount Wilson Ca II H + K fluxes comprise three principal parts: (1) a photospheric contribution in the line wings, (2) a basal chromospheric component that appears to be unrelated to stellar magnetic activity and is, therefore, possibly nonmagnetic in origin, and (3) a chromospheric component which is associated with magnetically active regions and the (quiet and active) network. The basal chromosphere appears to cover the entire surface of magnetically inactive stars. The basal Ca II H + K flux density for solar-type stars equals the average emission observed in the centers of solar supergranulation cells, where the magnetic flux density is small.

  6. Inferring ultraviolet anatomical exposure patterns while distinguishing the relative contribution of radiation components

    NASA Astrophysics Data System (ADS)

    Vuilleumier, Laurent; Milon, Antoine; Bulliard, Jean-Luc; Moccozet, Laurent; Vernez, David

    2013-05-01

    Exposure to solar ultraviolet (UV) radiation is the main causative factor for skin cancer. UV exposure depends on environmental and individual factors, but individual exposure data remain scarce. While ground UV irradiance is monitored via different techniques, it is difficult to translate such observations into human UV exposure or dose because of confounding factors. A multi-disciplinary collaboration developed a model predicting the dose and distribution of UV exposure on the basis of ground irradiation and morphological data. Standard 3D computer graphics techniques were adapted to develop a simulation tool that estimates solar exposure of a virtual manikin depicted as a triangle mesh surface. The amount of solar energy received by various body locations is computed for direct, diffuse and reflected radiation separately. Dosimetric measurements obtained in field conditions were used to assess the model performance. The model predicted exposure to solar UV adequately with a symmetric mean absolute percentage error of 13% and half of the predictions within 17% range of the measurements. Using this tool, solar UV exposure patterns were investigated with respect to the relative contribution of the direct, diffuse and reflected radiation. Exposure doses for various body parts and exposure scenarios of a standing individual were assessed using erythemally-weighted UV ground irradiance data measured in 2009 at Payerne, Switzerland as input. For most anatomical sites, mean daily doses were high (typically 6.2-14.6 Standard Erythemal Dose, SED) and exceeded recommended exposure values. Direct exposure was important during specific periods (e.g. midday during summer), but contributed moderately to the annual dose, ranging from 15 to 24% for vertical and horizontal body parts, respectively. Diffuse irradiation explained about 80% of the cumulative annual exposure dose.

  7. Inferring ultraviolet anatomical exposure patterns while distinguishing the relative contribution of radiation components

    SciTech Connect

    Vuilleumier, Laurent [Federal Office of Meteorology and Climatology, MeteoSwiss, Payerne (Switzerland); Milon, Antoine; Vernez, David [Institute of Work and Health, University of Lausanne and Geneva, Lausanne (Switzerland); Bulliard, Jean-Luc [Cancer Epidemiology Unit, Centre Hospitalier Universitaire Vaudois and University of Lausanne, Lausanne (Switzerland); Moccozet, Laurent [Institute of Services Science, University of Geneva (Switzerland)

    2013-05-10

    Exposure to solar ultraviolet (UV) radiation is the main causative factor for skin cancer. UV exposure depends on environmental and individual factors, but individual exposure data remain scarce. While ground UV irradiance is monitored via different techniques, it is difficult to translate such observations into human UV exposure or dose because of confounding factors. A multi-disciplinary collaboration developed a model predicting the dose and distribution of UV exposure on the basis of ground irradiation and morphological data. Standard 3D computer graphics techniques were adapted to develop a simulation tool that estimates solar exposure of a virtual manikin depicted as a triangle mesh surface. The amount of solar energy received by various body locations is computed for direct, diffuse and reflected radiation separately. Dosimetric measurements obtained in field conditions were used to assess the model performance. The model predicted exposure to solar UV adequately with a symmetric mean absolute percentage error of 13% and half of the predictions within 17% range of the measurements. Using this tool, solar UV exposure patterns were investigated with respect to the relative contribution of the direct, diffuse and reflected radiation. Exposure doses for various body parts and exposure scenarios of a standing individual were assessed using erythemally-weighted UV ground irradiance data measured in 2009 at Payerne, Switzerland as input. For most anatomical sites, mean daily doses were high (typically 6.2-14.6 Standard Erythemal Dose, SED) and exceeded recommended exposure values. Direct exposure was important during specific periods (e.g. midday during summer), but contributed moderately to the annual dose, ranging from 15 to 24% for vertical and horizontal body parts, respectively. Diffuse irradiation explained about 80% of the cumulative annual exposure dose.

  8. CLARO-CMOS: a fast, low power and radiation-hard front-end ASIC for single-photon counting in 0.35 micron CMOS technology

    NASA Astrophysics Data System (ADS)

    Andreotti, M.; Baldini, W.; Calabrese, R.; Carniti, P.; Cassina, L.; Cotta Ramusino, A.; Fiorini, M.; Giachero, A.; Gotti, C.; Luppi, E.; Maino, M.; Malaguti, R.; Pessina, G.; Tomassetti, L.

    2015-01-01

    The CLARO-CMOS is a prototype ASIC designed for fast photon counting with multi-anode photomultiplier tubes (MaPMT). The CLARO features a 5 ns peaking time, a recovery time to baseline smaller than 25 ns, and a power consumption of less than 1 mW per channel. The chip was designed in 0.35 ?m CMOS technology, and was tested for radiation hardness with neutrons up to 1014 1 MeV neq/cm2, X-rays up to 40 kGy and protons up to 76 kGy. Its capability to read out single photons at high rate from a Hamamatsu R11265 MaPMT, the baseline photon detector for the LHCb RICH upgrade, was demonstrated both with test bench measurements and with actual signals from a R11265 MaPMT. The presented results allowed CLARO to be chosen as the front-end readout chip in the upgraded LHCb RICH detector.

  9. Annual Conference on Nuclear and Space Radiation Effects, 17th, Cornell University, Ithaca, N.Y., July 15-18, 1980, Proceedings

    NASA Technical Reports Server (NTRS)

    Mcgarrity, J. M.

    1980-01-01

    The conference covered the radiation effects on devices, circuits, and systems, physics and basic radiation effects in materials, dosimetry and radiation transport, spacecraft charging, and space radiation effects. Other subjects included single particle upset phenomena, systems-generated electromagnetic pulse phenomena, fabrication of hardened components, testing techniques, and hardness assurance.

  10. Modeling dust as component minerals in the Community Atmosphere Model: development of framework and impact on radiative forcing

    SciTech Connect

    Scanza, Rachel; Mahowald, N.; Ghan, Steven J.; Zender, C. S.; Kok, J. F.; Liu, Xiaohong; Zhang, Y.; Albani, Samuel

    2015-01-01

    The mineralogy of desert dust is important due to its effect on radiation, clouds and biogeochemical cycling of trace nutrients. This study presents the simulation of dust radiative forcing as a function of both mineral composition and size at the global scale using mineral soil maps for estimating emissions. Externally mixed mineral aerosols in the bulk aerosol module in the Community Atmosphere Model version 4 (CAM4) and internally mixed mineral aerosols in the modal aerosol module in the Community Atmosphere Model version 5.1 (CAM5) embedded in the Community Earth System Model version 1.0.5 (CESM) are speciated into common mineral components in place of total dust. The simulations with mineralogy are compared to available observations of mineral atmospheric distribution and deposition along with observations of clear-sky radiative forcing efficiency. Based on these simulations, we estimate the all-sky direct radiative forcing at the top of the atmosphere as +0.05Wm?2 for both CAM4 and CAM5 simulations with mineralogy and compare this both with simulations of dust in release versions of CAM4 and CAM5 (+0.08 and +0.17Wm?2) and of dust with optimized optical properties, wet scavenging and particle size distribution in CAM4 and CAM5, ?0.05 and ?0.17Wm?2, respectively. The ability to correctly include the mineralogy of dust in climate models is hindered by its spatial and temporal variability as well as insufficient global in-situ observations, incomplete and uncertain source mineralogies and the uncertainties associated with data retrieved from remote sensing methods.

  11. Revealing a hard X-ray spectral component reverberating within one light hour of the central Supermassive Black Hole in Ark 564

    E-print Network

    Giustini, M; Reeves, J N; Miller, L; Legg, E; Kraemer, S B; George, I M

    2015-01-01

    Ark 564 (z=0.0247) is an X-ray bright NLS1. By using advanced X-ray timing techniques, Legg et al. (2012) discovered an excess of "delayed" emission in the hard X-ray band (4-7.5 keV) following about 1000 seconds after "flaring" light in the soft X-ray band (0.4-1 keV). We report on the X-ray spectral analysis of eight XMM-Newton and one Suzaku observation of Ark 564. High-resolution spectroscopy was performed with the RGS in the soft X-ray band, while broad-band spectroscopy was performed with the EPIC-pn and XIS/PIN instruments. We analysed time-averaged, flux-selected, and time-resolved spectra. Despite the large variability in flux, the broad band spectral shape of Ark 564 is not dramatically varying and can be reproduced either by a superposition of a power law and a blackbody emission, or by a Comptonized power law emission model. High resolution spectroscopy revealed the presence of ionised gas along the line of sight at the systemic redshift of the source, with a low column density and a range of ioni...

  12. Prevention of ultraviolet radiation-induced suppression of contact hypersensitivity by Aloe vera gel components.

    PubMed

    Lee, C K; Han, S S; Shin, Y K; Chung, M H; Park, Y I; Lee, S K; Kim, Y S

    1999-05-01

    We have recently reported that Aloe vera gel contains small molecular weight immunomodulators, G1C2F1, that restore ultraviolet B (UVB)-suppressed accessory cell function of epidermal Langerhans cells (LC) in vitro. In the present study we evaluated the UVB-protective activity of G1C2F1 in vivo. Exposure of the shaved abdominal skin of mice to 2.4 KJ/m2 of UVB radiation resulted in suppression of contact sensitization through the skin to 41.1%, compared to normal unirradiated skin. Topical application of G1C2F1 immediately after irradiation reduced this suppression significantly. The percentage recovery of UVB-suppressed contact hypersensitivity (CHS) response was 52.3, 77.3, and 86.6% when the irradiated skin was treated once with 0.1, 0.5, and 2.5 mg/ml of G1C2F1-containing cream, respectively. G1C2F1 did not show nonspecific stimulatory activity on CHS response. The present study, together with the previous observation, show that Aloe vera gel contains small molecular weight immunomodulators that prevent UVB-induced immune suppression in the skin by restoration of UVB-induced damages on epidermal LC. PMID:10408627

  13. Radiation damage and repair in cells and cell components. Progress report, 1980-1981

    SciTech Connect

    Not Available

    1981-01-01

    One aim has been to see whether, in E.coli, the various phenomena which were ascribed to the induction of the recA gene produce (p-recA) are really manifestations of one process. It was concluded that this is true for septum inhibition, Weigle-reactivation, induced inhibition of post radiation DNA degradation, and with the additional concept of a premutational lesion, for uv mutagenesis. lambda prophage induction may perhaps be brought into line with p-recA induction with the consideration of the additional secondary aspects of (a) activation of p-recA to make it enzymatically active and (b) the need to have the concentration of activated p-recA high enough to keep up with the rate of production of lambda-repressors. Revertants seem to be in more than one class and two of these can not easily be explained by the idea that p-recA contains an error-prone repair enzyme that makes errors at mutagenic lesions.

  14. Physics-based modeling of power system components for the evaluation of low-frequency radiated electromagnetic fields

    NASA Astrophysics Data System (ADS)

    Barzegaranbaboli, Mohammadreza

    The low-frequency electromagnetic compatibility (EMC) is an increasingly important aspect in the design of practical systems to ensure the functional safety and reliability of complex products. The opportunities for using numerical techniques to predict and analyze system's EMC are therefore of considerable interest in many industries. As the first phase of study, a proper model, including all the details of the component, was required. Therefore, the advances in EMC modeling were studied with classifying analytical and numerical models. The selected model was finite element (FE) modeling, coupled with the distributed network method, to generate the model of the converter's components and obtain the frequency behavioral model of the converter. The method has the ability to reveal the behavior of parasitic elements and higher resonances, which have critical impacts in studying EMI problems. For the EMC and signature studies of the machine drives, the equivalent source modeling was studied. Considering the details of the multi-machine environment, including actual models, some innovation in equivalent source modeling was performed to decrease the simulation time dramatically. Several models were designed in this study and the voltage current cube model and wire model have the best result. The GA-based PSO method is used as the optimization process. Superposition and suppression of the fields in coupling the components were also studied and verified. The simulation time of the equivalent model is 80-100 times lower than the detailed model. All tests were verified experimentally. As the application of EMC and signature study, the fault diagnosis and condition monitoring of an induction motor drive was developed using radiated fields. In addition to experimental tests, the 3DFE analysis was coupled with circuit-based software to implement the incipient fault cases. The identification was implemented using ANN for seventy various faulty cases. The simulation results were verified experimentally. Finally, the identification of the types of power components were implemented. The results show that it is possible to identify the type of components, as well as the faulty components, by comparing the amplitudes of their stray field harmonics. The identification using the stray fields is nondestructive and can be used for the setups that cannot go offline and be dismantled.

  15. IC and Component Selection for Space Systems

    NASA Technical Reports Server (NTRS)

    Label, Kenneth A.; Cohn, Lewis M.

    2007-01-01

    This viewgraph presentation reviews the integrated circuit (IC) and selections of the IC components for space systems. Included in the discussion are a overview of semiconductors and the evolution of integrated circuit. It also reviews the three different viewpoints of the IC selection: technical, programmatic, and risk. From a radiation perspective there are four criteria for selecting ICs for space systems: guaranteed hardness, historical ground-based data, historical flight usage, and unknown assurance.

  16. A Technique Using Principal Component Analysis to Compare Seasonal Cycles of Earth Radiation from CERES and Model Computations

    NASA Technical Reports Server (NTRS)

    Smith, G. Louis; Mlynczak, Pamela E.; Potter, Gerald L.

    2012-01-01

    A method for quantitatively comparing the seasonal cycles of two global data sets is presented. The seasonal cycles of absorbed solar radiation (ASR) and outgoing longwave radiation (OLR) have been computed from an eight-year data set from the Clouds and Earth's Radiant Energy System (CERES) scanning radiometers and from a model data set produced by the NASA Goddard Space Flight Center Global Modeling and Assimilation Office. To compare the seasonal cycles from these two data sets, principal component (PC) analysis is used, where the PCs express the time variations and the corresponding empirical orthogonal functions (EOFs) describe the geographic variations. Ocean has a long thermal response time compared to land, so land and ocean are separated for the analysis. The root-mean square values for the seasonal cycles of ASR and OLR are extremely close for the two data sets. The first three PCs are quite close, showing that the time responses and magnitudes over the globe are very similar. The agreement between the two sets of PCs is quantified by computing the matrix of inner products of the two sets. For ASR over land, the first PCs of CERES and the model agree to better than 99.9%. The EOF maps are similar for most of the globe, but differ in a few places, and the agreement of the EOF maps is likewise quantified. Maps of differences between the annual cycles show regions of agreement and disagreement.

  17. A radiation hard vacuum switch

    DOEpatents

    Boettcher, G.E.

    1988-07-19

    A vacuum switch with an isolated trigger probe which is not directly connected to the switching electrodes. The vacuum switch within the plasmatron is triggered by plasma expansion initiated by the trigger probe which travels through an opening to reach the vacuum switch elements. The plasma arc created is directed by the opening to the space between the anode and cathode of the vacuum switch to cause conduction. 3 figs.

  18. Diagnostic Components in Harsh Radiation Environments: Possible Overlap in R&D Requirements of IC and MF Systems

    SciTech Connect

    Bourgade, J L; Costley, A E; Reichle, R; Hodgson, E R; Hsing, W; Glebov, V; Decreton, M; Leeper, R; Leray, J L; Dentan, M; Hutter, T; Morono, A; Eder, D; Shmayda, W; Brichard, B; Baggio, J; Bertalot, L; Vayakis, G; Moran, M; Sangster, T C; Vermeeren, L; Stoeckl, C; Girard, S; Pien, G

    2008-05-08

    The next generation of large scale fusion devices--ITER/LMJ/NIF--will require diagnostic components to operate in environments far more severe than those encountered in present facilities. This harsh environment will be induced by fluxes of neutrons, gamma rays, energetic ions, electromagnetic radiation, and in some cases debris and shrapnel, at levels several orders of magnitude higher than those experienced in today's devices. For several years the question of possible synergy between inertial and the magnetic confinement research has been pursued by members of the respective communities. A first joint workshop specifically devoted to the identification and promotion of these synergies was organized in France, at Aix-en-Provence from June 27th to 29th, 2007. The workshop was attended by about 50 invited specialists. The participants identified a number of subject areas where common overlapping interests could benefit from additional interactions and meetings: windows, optical fibers, mirrors, cables, electronic components and 14 MeV neutron sources. In this paper we summarize the findings of these working groups. We put the discussion into context by including a brief description of the environments and the physical effects that have to be handled.

  19. Generalized cubic equation of state and the radial distribution functions at contact for multi-component hard-sphere mixtures with large size ratio

    NASA Astrophysics Data System (ADS)

    Sun, Jiu-Xun; Wu, Qiang; Cai, Ling-Cang; Jin, Ke

    2014-06-01

    A generalized cubic (GC) equation of state (EOS) with two independent parameters is proposed. The GC EOS can include EOS from both virial and compressibility routes of Percus-Yevick theory in it as special cases. The two parameters are determined by fitting well-known virial coefficients of pure fluid. The generalized cubic EOS can be directly and consistently extended to multi-component mixtures merely demanding of the EOS of mixtures also is cubic, and combining two strict physical conditions for the radial distribution functions at contact (RDFC) of mixtures. The calculated virial coefficients of pure fluid and predicted compressibility factors and RDFC for both pure fluid and mixtures are excellent as compared with the simulation data. The values of RDFC for mixtures with extremely large size ratio are far better than the expressions in literature.

  20. Calculating radiation exposures during use of (14)C-labeled nutrients, food components, and biopharmaceuticals to quantify metabolic behavior in humans.

    PubMed

    Kim, Seung-Hyun; Kelly, Peter B; Clifford, Andrew J

    2010-04-28

    (14)C has long been used as a tracer for quantifying the in vivo human metabolism of food components, biopharmaceuticals, and nutrients. Minute amounts (< or =1 x 10 (-18) mol) of (14)C can be measured with high-throughput (14)C-accelerator mass spectrometry (HT (14)C-AMS) in isolated chemical extracts of biological, biomedical, and environmental samples. Availability of in vivo human data sets using a (14)C tracer would enable current concepts of the metabolic behavior of food components, biopharmaceuticals, or nutrients to be organized into models suitable for quantitative hypothesis testing and determination of metabolic parameters. In vivo models are important for specification of intake levels for food components, biopharmaceuticals, and nutrients. Accurate estimation of the radiation exposure from ingested (14)C is an essential component of the experimental design. Therefore, this paper illustrates the calculation involved in determining the radiation exposure from a minute dose of orally administered (14)C-beta-carotene, (14)C-alpha-tocopherol, (14)C-lutein, and (14)C-folic acid from four prior experiments. The administered doses ranged from 36 to 100 nCi, and radiation exposure ranged from 0.12 to 5.2 microSv to whole body and from 0.2 to 3.4 microSv to liver with consideration of tissue weighting factor and fractional nutrient. In comparison, radiation exposure experienced during a 4 h airline flight across the United States at 37000 ft was 20 microSv. PMID:20349979

  1. Production of CMS FPIX detector modules and development of novel radiation-hard silicon sensors for future upgrades of the LHC

    NASA Astrophysics Data System (ADS)

    Koybasi, Ozhan

    The Compact Muon Solenoid (CMS) experiment currently taking data at the Large Hadron Collider (LHC) has the largest ever built all-silicon tracking system with a pixel detector as the innermost component. The pixel detector consists of three 53 cm long barrel layers (BPIX) at radial distances of r= 4.4, 7.3, and 10.2 cm from the interaction point complemented with two end-cap disks (FPIX) on each side of the interaction region covering radial distances from ˜6 cm to 15 cm. The development, production, and qualification of the silicon detector modules used for the construction of the CMS FPIX disks are described. The plan for the luminosity upgrade of the LHC foresees a phase I upgrade increasing the peak luminosity from 1034 cm.2s.1 (original design figure) to 2-3 x 1034 cm-2s-1 after about 5 years of operation, followed by phase II upgrade eventually reaching a value of 5x1034 cm-2 s-1 (the so-called "High Luminosity-LHC" or "HL-LHC"). At Phase I, the CMS pixel detector will be replaced by a new detector, which will have an additional fourth barrel layer at r=16 cm and two extra forward disks on each side with radial coverage of all disks increased to r =4.5-16.1 cm. Although the present non- n silicon pixel sensor technology meets the performance requirements, it is possible to achieve the same performance with the relatively new n-on-p technology, which would reduce the cost by ˜50%. The phase II upgrade, on the other hand, faces a challenge for the detector technology to be adopted for the innermost tracking layers (at r ˜ 4 cm) where the radiation fluence is expected to reach values close to 1016 neq /cm2, since the conventional planar silicon sensors are functional only up to a fluence of ˜1015 neq/cm2. The 3D silicon sensor technology is regarded as one of the most promising solutions for the radiation tolerance requirements of innermost pixel tracking layers at the HL-LHC. Improvements to the current n-on-n silicon pixel sensor design; and development of n-on-p planar silicon and of 3D silicon sensor technologies are presented.

  2. Comparison of proton therapy techniques for treatment of the whole brain as a component of craniospinal radiation

    PubMed Central

    2013-01-01

    Background For treatment of the entire cranium using passive scattering proton therapy (PSPT) compensators are often employed in order to reduce lens and cochlear exposure. We sought to assess the advantages and consequences of utilizing compensators for the treatment of the whole brain as a component of craniospinal radiation (CSI) with PSPT. Moreover, we evaluated the potential benefits of spot scanning beam delivery in comparison to PSPT. Methods Planning computed tomography scans for 50 consecutive CSI patients were utilized to generate passive scattering proton therapy treatment plans with and without Lucite compensators (PSW and PSWO respectively). A subset of 10 patients was randomly chosen to generate scanning beam treatment plans for comparison. All plans were generated using an Eclipse treatment planning system and were prescribed to a dose of 36 Gy(RBE), delivered in 20 fractions, to the whole brain PTV. Plans were normalized to ensure equal whole brain target coverage. Dosimetric data was compiled and statistical analyses performed using a two-tailed Student’s t-test with Bonferroni corrections to account for multiple comparisons. Results Whole brain target coverage was comparable between all methods. However, cribriform plate coverage was superior in PSWO plans in comparison to PSW (V95%; 92.9?±?14 vs. 97.4?±?5, p?component of CSI treatments, offers additional normal tissue sparing which is likely of clinical significance. PMID:24344645

  3. Considerations for IC and Component Selection for Space Systems

    NASA Technical Reports Server (NTRS)

    LaBel, Kenneth A.; Cohn, Lewis M.

    2008-01-01

    This viewgraph presentation addresses the integrated cycling and component selection technologies for aerospace systems. The topics include: 1) Semiconductors: The Evolution of ICs - Availability and Technology; 2) IC Selection Requirements - three fields of thought, "The Good", "The Bad" and "The Ugly"; 3) Reliability and Radiation; 4) Radiation Perspective-Four methods of selecting ICs for space systems, Guaranteed hardness, historical ground-based radiation data, historical flight usage, and unknown assurance; 5) Understanding Risk, including risk trade space and ASICs and FPGA sample selection criteria.

  4. Inclusion of an ultraviolet radiation transfer component in an urban forest effects model for predicting tree influences on potential below-canopy exposure to UVB radiation

    Microsoft Academic Search

    Gordon M. Heisler; Richard H. Grant; David J. Nowak; Wei Gao; Daniel E. Crane; Jeffrey T. Walton

    2003-01-01

    Evaluating the impact of ultraviolet-B radiation (UVB) on urban populations would be enhanced by improved predictions of the UVB radiation at the level of human activity. This paper reports the status of plans for incorporating a UVB prediction module into an existing Urban Forest Effects (UFORE) model. UFORE currently has modules to quantify urban forest structure, urban tree volatile organic

  5. Inclusion of an Ultraviolet Radiation Transfer Component in an Urban Forest Effects Model for Predicting Tree Influences on Potential Below-Canopy Exposure to WB Radiation

    Microsoft Academic Search

    Gordon M. Hei; David J. Nowak; Daniel E. Crane; Jeffrey T. Walton; USDA UV-B

    Evaluating the impact of ultraviolet-B radiation (UVB) on urban populations would be enhanced by improved predictions of the UVB radiation at the level of human activity. This paper reports the status of plans for incorporating a UVB prediction module into an existing Urban Forest Effects (UFORE) model. UFORE currently has modules to quantify urban forest structure, urban tree volatile organic

  6. Radiation

    Cancer.gov

    DCEG researchers carry out a broad-based research program designed to identify, understand, and quantify the risk of cancer in populations exposed to medical, occupational, or environmental radiation. They study ionizing radiation exposures (e.g., x-rays,

  7. Studies of beam induced radiation for experiment 735 at the CO interaction region and its effect on detector components

    Microsoft Academic Search

    F. Turkot; C. Hojvat; W. Anderson; C. S. Lindsey; N. Biswas; J. Piekarz; A. Bujak

    1985-01-01

    A series of measurement is reported that were conducted to evaluate the amount of radiation present in the Fermilab Collider tunnel under different circumstances. Also to be determined is the effect of radiation on scintillators, phototubes, and their electronics, possible damage to drift chamber wires due to high counting rates and possible damage to the drift chamber electronics. Background and

  8. Estimating reflected and emitted components of the radiation balance using remotely-sensed spectral data from KUREX-91

    NASA Technical Reports Server (NTRS)

    Blad, B. L.; Walter-Shea, E. A.; Mesarch, M. A.; Hays, C. J.; Deering, D.; Eck, T.

    1992-01-01

    The estimation of incoming and outgoing radiation streams using bidirectional spectral reflectances and bidirectional thermal emittances is described. Good agreement between measured and modeled estimates of the radiation balance is obtained. The data used were collected over selected grassland sites on the Streletskaya Steppe Reserve in Russia in July 1991. Results from this study compare well with results obtained during the first ISLSCP field experiment (FIFE) study in Kansas in 1987-89.

  9. The reversal of the rotational modulation rates of the north and south components of Saturn kilometric radiation near equinox

    E-print Network

    Gurnett, Donald A.

    The reversal of the rotational modulation rates of the north and south components of Saturn; accepted 15 November 2010; published 17 December 2010. [1] It has been known for many years that Saturn of the northern and southern components reversed near Saturn's recent equinox, which occurred on 11 August 2009

  10. Recombination dynamics of excitons with low non-radiative component in semi-polar (10-11)-oriented GaN/AlGaN multiple quantum wells

    SciTech Connect

    Rosales, D.; Gil, B.; Bretagnon, T.; Guizal, B. [CNRS, Laboratoire Charles Coulomb, UMR 5221, F-34095 Montpellier (France); Université Montpellier 2, Laboratoire Charles Coulomb, UMR 5221, F-34095 Montpellier (France); Izyumskaya, N.; Monavarian, M.; Zhang, F.; Okur, S.; Avrutin, V.; Özgür, Ü.; Morkoç, H. [Department of Electrical and Computer Engineering, Virginia Commonwealth University, Richmond, Virginia 23238 (United States)

    2014-09-07

    Optical properties of GaN/Al{sub 0.2}Ga{sub 0.8}N multiple quantum wells grown with semi-polar (10-11) orientation on patterned 7°-off Si (001) substrates have been investigated. Studies performed at 8?K reveal the in-plane anisotropic behavior of the QW photoluminescence (PL) intensity for this semi-polar orientation. The time resolved PL measurements were carried out in the temperature range from 8 to 295?K to deduce the effective recombination decay times, with respective radiative and non-radiative contributions. The non-radiative component remains relatively weak with increasing temperature, indicative of high crystalline quality. The radiative decay time is a consequence of contribution from both localized and free excitons. We report an effective density of interfacial defects of 2.3?×?10{sup 12} cm{sup ?2} and a radiative recombination time of ?{sub loc}?=?355 ps for the localized excitons. This latter value is significantly larger than those reported for the non-polar structures, which we attribute to the presence of a weak residual electric field in the semi-polar QW layers.

  11. Recombination dynamics of excitons with low non-radiative component in semi-polar (10-11)-oriented GaN/AlGaN multiple quantum wells

    NASA Astrophysics Data System (ADS)

    Rosales, D.; Gil, B.; Bretagnon, T.; Guizal, B.; Izyumskaya, N.; Monavarian, M.; Zhang, F.; Okur, S.; Avrutin, V.; Özgür, Ü.; Morkoç, H.

    2014-09-01

    Optical properties of GaN/Al0.2Ga0.8N multiple quantum wells grown with semi-polar (10-11) orientation on patterned 7°-off Si (001) substrates have been investigated. Studies performed at 8 K reveal the in-plane anisotropic behavior of the QW photoluminescence (PL) intensity for this semi-polar orientation. The time resolved PL measurements were carried out in the temperature range from 8 to 295 K to deduce the effective recombination decay times, with respective radiative and non-radiative contributions. The non-radiative component remains relatively weak with increasing temperature, indicative of high crystalline quality. The radiative decay time is a consequence of contribution from both localized and free excitons. We report an effective density of interfacial defects of 2.3 × 1012 cm-2 and a radiative recombination time of ?loc = 355 ps for the localized excitons. This latter value is significantly larger than those reported for the non-polar structures, which we attribute to the presence of a weak residual electric field in the semi-polar QW layers.

  12. Rad-hard electronics development program for SSC liquid-argon calorimeters

    SciTech Connect

    Stevens, A.; Dawson, J. (Argonne National Lab., IL (USA). High Energy Physics Div.); Kraner, H.; Radeka, V.; Rescia, S. (Brookhaven National Lab., Upton, NY (USA))

    1990-01-01

    The development program for radiation-hard low-noise low-power front-end electronics for SSC calorimetry is described. Radiation doses of up to 20 MRad and neutron fluences of 10{sup 14} neutrons/cm{sup 2} are expected over ten years of operation. These effects are simulated by exposing JFETs to neutrons and ionizing radiation and measuring the resulting bias, leakage current and noise variations. In the case of liquid-argon calorimeters, a large part of the front-end circuitry may be located directly within the low-temperature environment (90 K), placing additional constraints on the choice of components and on the design. This approach minimizes the noise and the response time. The radiation damage test facilities at Argonne will also be described. These include sources of neutrons, electrons, and gamma radiation. 8 refs., 9 figs.

  13. Hard Metal Disease

    PubMed Central

    Bech, A. O.; Kipling, M. D.; Heather, J. C.

    1962-01-01

    In Great Britain there have been no published reports of respiratory disease occurring amongst workers in the hard metal (tungsten carbide) industry. In this paper the clinical and radiological findings in six cases and the pathological findings in one are described. In two cases physiological studies indicated mild alveolar diffusion defects. Histological examination in a fatal case revealed diffuse pulmonary interstitial fibrosis with marked peribronchial and perivascular fibrosis and bronchial epithelial hyperplasia and metaplasia. Radiological surveys revealed the sporadic occurrence and low incidence of the disease. The alterations in respiratory mechanics which occurred in two workers following a day's exposure to dust are described. Airborne dust concentrations are given. The industrial process is outlined and the literature is reviewed. The toxicity of the metals is discussed, and our findings are compared with those reported from Europe and the United States. We are of the opinion that the changes which we would describe as hard metal disease are caused by the inhalation of dust at work and that the component responsible may be cobalt. Images PMID:13970036

  14. Activation of eNOS in endothelial cells exposed to ionizing radiation involves components of the DNA damage response pathway.

    PubMed

    Nagane, Masaki; Yasui, Hironobu; Sakai, Yuri; Yamamori, Tohru; Niwa, Koichi; Hattori, Yuichi; Kondo, Takashi; Inanami, Osamu

    2015-01-01

    In this study, the involvement of ataxia telangiectasia mutated (ATM) kinase and heat shock protein 90 (HSP90) in endothelial nitric oxide synthase (eNOS) activation was investigated in X-irradiated bovine aortic endothelial cells. The activity of nitric oxide synthase (NOS) and the phosphorylation of serine 1179 of eNOS (eNOS-Ser1179) were significantly increased in irradiated cells. The radiation-induced increases in NOS activity and eNOS-Ser1179 phosphorylation levels were significantly reduced by treatment with either an ATM inhibitor (Ku-60019) or an HSP90 inhibitor (geldanamycin). Geldanamycin was furthermore found to suppress the radiation-induced phosphorylation of ATM-Ser1181. Our results indicate that the radiation-induced eNOS activation in bovine aortic endothelial cells is regulated by ATM and HSP90. PMID:25498542

  15. A Radiation-Hard Dual Channel 4-bit Pipeline for a 12-bit 40 MS/s ADC Prototype with extended Dynamic Range for the ATLAS Liquid Argon Calorimeter Readout Electronics Upgrade at the CERN LHC

    E-print Network

    Jayanth Kuppambatti; Jaroslav Ban; Timothy Andeen; Peter Kinget; Gustaaf Brooijmans

    2013-07-31

    The design of a radiation-hard dual channel 12-bit 40 MS/s pipeline ADC with extended dynamic range is presented, for use in the readout electronics upgrade for the ATLAS Liquid Argon Calorimeters at the CERN Large Hadron Collider. The design consists of two pipeline A/D channels with four Multiplying Digital-to-Analog Converters with nominal 12-bit resolution each. The design, fabricated in the IBM 130 nm CMOS process, shows a performance of 68 dB SNDR at 18 MHz for a single channel at 40 MS/s while consuming 55 mW/channel from a 2.5 V supply, and exhibits no performance degradation after irradiation. Various gain selection algorithms to achieve the extended dynamic range are implemented and tested.

  16. A radiation-hard dual channel 4-bit pipeline for a 12-bit 40 MS/s ADC prototype with extended dynamic range for the ATLAS Liquid Argon Calorimeter readout electronics upgrade at the CERN LHC

    NASA Astrophysics Data System (ADS)

    Kuppambatti, J.; Ban, J.; Andeen, T.; Kinget, P.; Brooijmans, G.

    2013-09-01

    The design of a radiation-hard dual-channel 12-bit 40 MS/s pipeline ADC with extended dynamic range is presented, for use in the readout electronics upgrade for the ATLAS Liquid Argon Calorimeters at the CERN Large Hadron Collider. The design consists of two pipeline A/D channels with four Multiplying Digital-to-Analog Converters with nominal 12-bit resolution each. The design, fabricated in the IBM 130 nm CMOS process, shows a performance of 68 dB SNDR at 18 MHz for a single channel at 40 MS/s while consuming 55 mW/channel from a 2.5 V supply, and exhibits no performance degradation after irradiation. Various gain selection algorithms to achieve the extended dynamic range are implemented and tested.

  17. The in vivo effects of 2.45 GHz microwave radiation on rabbit serum components and sleeping times

    Microsoft Academic Search

    R. T. Wangemann; S. F. Cleary

    1976-01-01

    Summary An investigation was conducted to determine the effects of relatively low power density microwave exposures on various serum components of the Dutch rabbit. Both continuous wave and pulsed mode exposures at 2.45 GHz were used at power densities of 25, 10 and 5 mW\\/cm2. Studies of 10 serum components were performed. Additional studies were conducted on changes in sleeping

  18. Ultra-Low Power High Temperature and Radiation Hard Complementary Metal-Oxide-Semiconductor (CMOS) Silicon-on-Insulator (SOI) Voltage Reference

    PubMed Central

    Boufouss, El Hafed; Francis, Laurent A.; Kilchytska, Valeriya; Gérard, Pierre; Simon, Pascal; Flandre, Denis

    2013-01-01

    This paper presents an ultra-low power CMOS voltage reference circuit which is robust under biomedical extreme conditions, such as high temperature and high total ionized dose (TID) radiation. To achieve such performances, the voltage reference is designed in a suitable 130 nm Silicon-on-Insulator (SOI) industrial technology and is optimized to work in the subthreshold regime of the transistors. The design simulations have been performed over the temperature range of ?40–200 °C and for different process corners. Robustness to radiation was simulated using custom model parameters including TID effects, such as mobilities and threshold voltages degradation. The proposed circuit has been tested up to high total radiation dose, i.e., 1 Mrad (Si) performed at three different temperatures (room temperature, 100 °C and 200 °C). The maximum drift of the reference voltage VREF depends on the considered temperature and on radiation dose; however, it remains lower than 10% of the mean value of 1.5 V. The typical power dissipation at 2.5 V supply voltage is about 20 ?W at room temperature and only 75 ?W at a high temperature of 200 °C. To understand the effects caused by the combination of high total ionizing dose and temperature on such voltage reference, the threshold voltages of the used SOI MOSFETs were extracted under different conditions. The evolution of VREF and power consumption with temperature and radiation dose can then be explained in terms of the different balance between fixed oxide charge and interface states build-up. The total occupied area including pad-ring is less than 0.09 mm2. PMID:24351635

  19. Rad-Hard/HI-REL FPGA

    NASA Technical Reports Server (NTRS)

    Wang, Jih-Jong; Cronquist, Brian E.; McGowan, John E.; Katz, Richard B.

    1997-01-01

    The goals for a radiation hardened (RAD-HARD) and high reliability (HI-REL) field programmable gate array (FPGA) are described. The first qualified manufacturer list (QML) radiation hardened RH1280 and RH1020 were developed. The total radiation dose and single event effects observed on the antifuse FPGA RH1280 are reported on. Tradeoffs and the limitations in the single event upset hardening are discussed.

  20. Ab initio Based Modeling of Radiation Effects in MultiComponent Alloys: Final Scientific\\/Technical Report

    Microsoft Academic Search

    Dane Morgan

    2010-01-01

    The project began March 13, 2006, allocated for three years, and received a one year extension from March 13, 2009 to March 12, 2010. It has now completed 48 of 48 total months. The project was focused on using ab initio methods to gain insights into radiation induced segregation (RIS) in Ni-Fe-Cr alloys. The project had the following key accomplishments;

  1. Resistance of Bacillus subtilis Spore DNA to Lethal Ionizing Radiation Damage Relies Primarily on Spore Core Components and DNA Repair, with Minor Effects of Oxygen Radical Detoxification

    PubMed Central

    Raguse, Marina; Reitz, Günther; Okayasu, Ryuichi; Li, Zuofeng; Klein, Stuart; Setlow, Peter; Nicholson, Wayne L.

    2014-01-01

    The roles of various core components, including ?/?/?-type small acid-soluble spore proteins (SASP), dipicolinic acid (DPA), core water content, and DNA repair by apurinic/apyrimidinic (AP) endonucleases or nonhomologous end joining (NHEJ), in Bacillus subtilis spore resistance to different types of ionizing radiation including X rays, protons, and high-energy charged iron ions have been studied. Spores deficient in DNA repair by NHEJ or AP endonucleases, the oxidative stress response, or protection by major ?/?-type SASP, DPA, and decreased core water content were significantly more sensitive to ionizing radiation than wild-type spores, with highest sensitivity to high-energy-charged iron ions. DNA repair via NHEJ and AP endonucleases appears to be the most important mechanism for spore resistance to ionizing radiation, whereas oxygen radical detoxification via the MrgA-mediated oxidative stress response or KatX catalase activity plays only a very minor role. Synergistic radioprotective effects of ?/?-type but not ?-type SASP were also identified, indicating that ?/?-type SASP's binding to spore DNA is important in preventing DNA damage due to reactive oxygen species generated by ionizing radiation. PMID:24123749

  2. RAD hard PROM design study

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The results of a preliminary study on the design of a radiation hardened fusible link programmable read-only memory (PROM) are presented. Various fuse technologies and the effects of radiation on MOS integrated circuits are surveyed. A set of design rules allowing the fabrication of a radiation hardened PROM using a Si-gate CMOS process is defined. A preliminary cell layout was completed and the programming concept defined. A block diagram is used to describe the circuit components required for a 4 K design. A design goal data sheet giving target values for the AC, DC, and radiation parameters of the circuit is presented.

  3. Irradiate-anneal screening of total dose effects in semiconductor devices. [radiation hardening of spacecraft components of Mariner spacecraft

    NASA Technical Reports Server (NTRS)

    Stanley, A. G.; Price, W. E.

    1976-01-01

    An extensive investigation of irradiate-anneal (IRAN) screening against total dose radiation effects was carried out as part of a program to harden the Mariner Jupiter/Saturn 1977 (MJS'77) spacecraft to survive the Jupiter radiation belts. The method consists of irradiating semiconductor devices with Cobalt-60 to a suitable total dose under representative bias conditions and of separating the parts in the undesired tail of the distribution from the bulk of the parts by means of a predetermined acceptance limit. The acceptable devices are then restored close to their preirradiation condition by annealing them at an elevated temperature. IRAN was used when lot screen methods were impracticable due to lack of time, and when members of a lot showed a diversity of radiation response. The feasibility of the technique was determined by testing of a number of types of linear bipolar integrated circuits, analog switches, n-channel JFETS and bipolar transistors. Based on the results of these experiments a number of device types were selected for IRAN of flight parts in the MJS'77 spacecraft systems. The part types, screening doses, acceptance criteria, number of parts tested and rejected as well as the program steps are detailed.

  4. Production of CMS FPIX detector modules and development of novel radiation-hard silicon sensors for future upgrades of the LHC

    Microsoft Academic Search

    Ozhan Koybasi

    2011-01-01

    The Compact Muon Solenoid (CMS) experiment currently taking data at the Large Hadron Collider (LHC) has the largest ever built all-silicon tracking system with a pixel detector as the innermost component. The pixel detector consists of three 53 cm long barrel layers (BPIX) at radial distances of r= 4.4, 7.3, and 10.2 cm from the interaction point complemented with two

  5. Rockwell Hardness Measurement of

    E-print Network

    Colton, Jonathan S.

    960-5 Rockwell Hardness Measurement of Metallic Materials Samuel R. Low NISTrecommended p r a c t i c e g u i d e Special Publication 960-5 #12;i Rockwell Hardness Measurement of Metallic Materials: (202) 512­2250 Mail: Stop SSOP, Washington, DC 20402-0001 #12;N FOREWORD The Rockwell hardness test

  6. BOOKSHELF Hard Disk Drive

    E-print Network

    Benmei, Chen

    - widths ever higher as higher frequency disturbances become relevant. THE BOOK Hard Disk Drive Servo examples. In chapters 2­5 of Hard Disk Drive Servo Systems it is easy to forget that one is reading a book about disk drive control rather than a book on general control theory. Hard Disk Drive Servo Systems

  7. A Comparison of Out-of-Field Dose and Its Constituent Components for Intensity-Modulated Radiation Therapy Versus Conformal Radiation Therapy: Implications for Carcinogenesis

    SciTech Connect

    Ruben, Jeremy D., E-mail: jeremy.ruben@wbrc.org.au [William Buckland Radiotherapy Centre, The Alfred, Melbourne (Australia); Monash University, Melbourne (Australia); Lancaster, Craig M.; Jones, Phillip; Smith, Ryan L. [William Buckland Radiotherapy Centre, The Alfred, Melbourne (Australia)

    2011-12-01

    Purpose: To investigate differences in scatter and leakage between 6-MV intensity-modulated radiation therapy (IMRT) and three-dimensional conformal radiation therapy (3DCRT); to describe the relative contributions of internal patient scatter, collimator scatter, and head leakage; and to discuss implications for second cancer induction. Methods and Materials: Dose was measured at increasing distances from the field edge in a water bath with a sloping wall (1) under full scatter conditions, (2) with the field edge abutting but outside the bath to prevent internal (water) scatter, and (3) with the beam aperture plugged to reflect leakage only. Results: Internal patient scatter from IMRT is 11% lower than 3DCRT, but collimator scatter and head leakage are five and three times higher, respectively. Ultimately, total scattered dose is 80% higher with IMRT; however this difference is small in absolute terms, being 0.14% of prescribed dose. Secondary dose from 3DCRT is mostly due to internal patient scatter, which contributes 70% of the total and predominates until 25 cm from the field edge. For IMRT, however, machine scatter/leakage is the dominant source, contributing 65% of the secondary dose. Internal scatter predominates for just the first 10 cm from field edge, collimator scatter for the next 10 cm, and head leakage thereafter. Conclusions: Out-of-field dose is 80% higher with IMRT, but differences are tiny in absolute terms. Reductions in internal patient scatter with IMRT are outweighed by increased machine scatter and leakage, at least for small fields. Reductions from IMRT in dose to tissues within the portals and in internal scatter, which predominates close to the field edge, means that calculations based solely on dose to distant tissues may overestimate carcinogenic risks.

  8. Inclusion of an ultraviolet radiation transfer component in an urban forest effects model for predicting tree influences on potential below-canopy exposure to UVB radiation

    NASA Astrophysics Data System (ADS)

    Heisler, Gordon M.; Grant, Richard H.; Nowak, David J.; Gao, Wei; Crane, Daniel E.; Walton, Jeffrey T.

    2003-11-01

    Evaluating the impact of ultraviolet-B radiation (UVB) on urban populations would be enhanced by improved predictions of the UVB radiation at the level of human activity. This paper reports the status of plans for incorporating a UVB prediction module into an existing Urban Forest Effects (UFORE) model. UFORE currently has modules to quantify urban forest structure, urban tree volatile organic compound emissions, carbon storage and sequestration in urban vegetation, dry deposition of air pollutants on trees, tree influences on energy use for heating and cooling buildings, tree pollen allergenicity index, and replacement cost of trees. These modeled effects are based upon field sampling to characterize land use, vegetation cover, and building features. The field sampling includes recording of tree species, total height, height to base of live crown, and crown width on randomly selected 0.04-ha (0.1 acre) plots. Distance and direction from sampled trees to buildings are also measured. The input for UFORE modeling of effects includes hourly meteorological data and pollution-concentration data. UFORE has already been used in assessing the urban forest functionof 13 cities in the United States and 5 cities in other countries. The objective of the present work is to enable UFORE to predict the effect of different urban tree densities on potential average human exposure to UVB. The current version of UFORE is written using the Statistical Analysis System (SAS); a new version will be a user-friendly Windows application and will be available for wide distribution. Progress to date on the UVB module consists primarily of examining available modeling and data collection tools. Two methods are proposed for the UVB module. In Method 1, we will derive predicted UVB irradiance at person height, that is, below the urban tree and building canopy, using gap fractions (sky view portions) measured from digitized fisheye photos taken from each of the UFORE plot centers during a UFORE field survey. A promising method for analyzing the photos is the use of Gap Light Analyzer (GLA). A human thermal comfort model will be used to determine the times when people would be comfortable outdoors in light attire, and UVB will be determined for those times. Method 2 will be applied in cases where hemispherical photos cannot be made available, and for making predictions for cities where surveys have already been done. Method 2 will use a 3D canopy UV radiation transfer model to derive based on tree canopy cover maps from GIS analysis of aerial color IR photographs or Landsat TM images. The UV module addition to UFORE will make it useful in epidemiology of UV-related human disease and assessment of UV benefits, such as in vitamin D production, and it will also facilitate consideration of UV exposure in urban forest management.

  9. COMPONENTS OF LASER SYSTEMS: Noise radiation power of phase-conjugate mirrors based on a degenerate four-wave mixing

    NASA Astrophysics Data System (ADS)

    Kovalev, Valerii I.

    1995-11-01

    An experimental investigation was made of the influence of the state of optically polished surfaces of various materials on the scattering coefficient which governs the power of the intrinsic noise of phase-conjugate mirrors based on a degenerate four-wave interaction. The angular dependence of this coefficient was also investigated. The noise power of a phase-conjugate mirror made of InAs, operating at the optimal pump wave intensities 1— 2 MW cm-2, may be reduced to ~2 × 10-7 W per one spatial mode of the radiation to be phase-conjugated. This was achieved by increasing the angle between the axes of the signal and the pump beams up to ~1 rad without a significant reduction of the reflection efficiency, which can be ~500%.

  10. Weak solar flares with a detectable flux of hard X rays: Specific features of microwave radiation in the corresponding active regions

    NASA Astrophysics Data System (ADS)

    Grigor'eva, I. Yu.; Livshits, M. A.

    2014-12-01

    The emission of very weak flares was registered at the Suzaku X-ray observatory in 2005-2009. The photon power spectrum in the 50-110 keV range for a number of these phenomena shows that some electrons accelerate to energies higher than 100 keV. The corresponding flares originate in active regions (ARs) with pronounced sunspots. As in the case of AR 10933 in January 2007 analyzed by us previously (Grigor'eva et al., 2013), the thoroughly studied weak flares in May 2007 are related to the emergence of a new magnetic field in the AR and to the currents that originate in this case. A comparison of the Suzaku data with the RATAN-600 microwave observations indicates that a new polarized source of microwave radiation develops in the AR (or the previously existing source intensifies) one-two days before a weak flare in the emerging flux regions. Arguments in favor of recent views that fields are force-free in the AR corona are put forward. The development of weak flares is related to the fact that the free energy of the currents that flow above the field neutral line at altitudes reaching several thousand kilometers is accumulated and subsequently released.

  11. Design and First Tests of a Radiation-Hard Pixel Sensor for the European X-Ray Free-Electron Laser

    NASA Astrophysics Data System (ADS)

    Schwandt, Joern; Fretwurst, Eckhart; Klanner, Robert; Kopsalis, Ioannis; Zhang, Jiaguo

    2014-08-01

    The high intensity and high repetition rate of the European X-ray Free-Electron Laser, presently under construction in Hamburg, requires silicon sensors which can stand X-ray doses of up to 1 GGy for 3 years of operation at high bias voltage. Within the AGIPD Collaboration the X-ray-radiation damage in MOS Capacitors and Gate-Controlled Diodes fabricated by four vendors on high-ohmic n-type silicon with two crystal orientations and dif- ferent technological parameters, has been studied for doses between 1 kGy and 1 GGy. The extracted values of oxide-charge and surface-current densi- ties have been used in TCAD simulations, and the layout and technological parameters of the AGIPD pixel sensor optimized. It is found that the op- timized layout for high X-ray doses is significantly different from the one for non-irradiated sensors. First sensors and test structures have been de-livered in early 2013. Measurement results for X-ray doses of 0 to 10 MGy and their comparison to simulations are presented. They demonstrate that the optimization has been successful and that the sensors fulfill the required specifications.

  12. Radiation hardness tests and characterization of the CLARO-CMOS, a low power and fast single-photon counting ASIC in 0.35 micron CMOS technology

    NASA Astrophysics Data System (ADS)

    Fiorini, M.; Andreotti, M.; Baldini, W.; Calabrese, R.; Carniti, P.; Cassina, L.; Cotta Ramusino, A.; Giachero, A.; Gotti, C.; Luppi, E.; Maino, M.; Malaguti, R.; Pessina, G.; Tomassetti, L.

    2014-12-01

    The CLARO-CMOS is a prototype ASIC that allows fast photon counting with 5 ns peaking time, a recovery time to baseline smaller than 25 ns, and a power consumption of less than 1 mW per channel. This chip is capable of single-photon counting with multi-anode photomultipliers and finds applications also in the read-out of silicon photomultipliers and microchannel plates. The prototype is realized in AMS 0.35 micron CMOS technology. In the LHCb RICH environment, assuming 10 years of operation at the nominal luminosity expected after the upgrade in Long Shutdown 2 (LS2), the ASIC must withstand a total fluence of about 6×1012 1 MeV neq /cm2 and a total ionizing dose of 400 krad. A systematic evaluation of the radiation effects on the CLARO-CMOS performance is therefore crucial to ensure long term stability of the electronics front-end. The results of multi-step irradiation tests with neutrons and X-rays up to the fluence of 1014 cm-2 and a dose of 4 Mrad, respectively, are presented, including measurement of single event effects during irradiation and chip performance evaluation before and after each irradiation step.

  13. Design and First Tests of a Radiation-Hard Pixel Sensor for the European X-Ray Free-Electron Laser

    E-print Network

    Schwandt, Joern; Klanner, Robert; Kopsalis, Ioannis; Zhang, Jiaguo

    2014-01-01

    The high intensity and high repetition rate of the European X-ray Free-Electron Laser, presently under construction in Hamburg, requires silicon sensors which can stand X-ray doses of up to 1 GGy for 3 years of operation at high bias voltage. Within the AGIPD Collaboration the X-ray-radiation damage in MOS Capacitors and Gate-Controlled Diodes fabricated by four vendors on high-ohmic n-type silicon with two crystal orientations and dif- ferent technological parameters, has been studied for doses between 1 kGy and 1 GGy. The extracted values of oxide-charge and surface-current densi- ties have been used in TCAD simulations, and the layout and technological parameters of the AGIPD pixel sensor optimized. It is found that the op- timized layout for high X-ray doses is significantly different from the one for non-irradiated sensors. First sensors and test structures have been de-livered in early 2013. Measurement results for X-ray doses of 0 to 10 MGy and their comparison to simulations are presented. They demons...

  14. Ab initio Based Modeling of Radiation Effects in Multi-Component Alloys: Final Scientific/Technical Report

    SciTech Connect

    Dane Morgan

    2010-06-10

    The project began March 13, 2006, allocated for three years, and received a one year extension from March 13, 2009 to March 12, 2010. It has now completed 48 of 48 total months. The project was focused on using ab initio methods to gain insights into radiation induced segregation (RIS) in Ni-Fe-Cr alloys. The project had the following key accomplishments • Development of a large database of ab initio energetics that can be used by many researchers in the future for increased understanding of this system. For example, we have the first calculations showing a dramatic stabilization effect of Cr-Cr interstitial dumbbells in Ni. • Prediction of both vacancy and interstitial diffusion constants for Ni-Cr and Ni-Fe for dilute Cr and Fe. This work included generalization of widely used multifrequency models to make use of ab initio derived energetics and thermodynamics. • Prediction of qualitative trends of RIS from vacancy and interstitial mechanisms, suggesting the two types of defect fluxes drive Cr RIS in opposite directions. • Detailed kinetic Monte Carlo modeling of diffusion by vacancy mechanism in Ni-Cr as a function of Cr concentration. The results demonstrate that Cr content can have a significant effect on RIS. • Development of a quantitative RIS transport model, including models for thermodynamic factors and boundary conditions.

  15. Ultrasonic material hardness depth measurement

    DOEpatents

    Good, Morris S. (Richland, WA); Schuster, George J. (Kennewick, WA); Skorpik, James R. (Kennewick, WA)

    1997-01-01

    The invention is an ultrasonic surface hardness depth measurement apparatus and method permitting rapid determination of hardness depth of shafts, rods, tubes and other cylindrical parts. The apparatus of the invention has a part handler, sensor, ultrasonic electronics component, computer, computer instruction sets, and may include a display screen. The part handler has a vessel filled with a couplant, and a part rotator for rotating a cylindrical metal part with respect to the sensor. The part handler further has a surface follower upon which the sensor is mounted, thereby maintaining a constant distance between the sensor and the exterior surface of the cylindrical metal part. The sensor is mounted so that a front surface of the sensor is within the vessel with couplant between the front surface of the sensor and the part.

  16. Ultrasonic material hardness depth measurement

    DOEpatents

    Good, M.S.; Schuster, G.J.; Skorpik, J.R.

    1997-07-08

    The invention is an ultrasonic surface hardness depth measurement apparatus and method permitting rapid determination of hardness depth of shafts, rods, tubes and other cylindrical parts. The apparatus of the invention has a part handler, sensor, ultrasonic electronics component, computer, computer instruction sets, and may include a display screen. The part handler has a vessel filled with a couplant, and a part rotator for rotating a cylindrical metal part with respect to the sensor. The part handler further has a surface follower upon which the sensor is mounted, thereby maintaining a constant distance between the sensor and the exterior surface of the cylindrical metal part. The sensor is mounted so that a front surface of the sensor is within the vessel with couplant between the front surface of the sensor and the part. 12 figs.

  17. Radiation Is an Important Component of Multimodality Therapy for Pediatric Non-Pineal Supratentorial Primitive Neuroectodermal Tumors

    SciTech Connect

    McBride, Sean M.; Daganzo, Sally M. [Department of Radiation Oncology, University of California-San Francisco, San Francisco, CA (United States); Banerjee, Anuradha [Department of Pediatrics, University of California-San Francisco, San Francisco, CA (United States); Gupta, Nalin; Lamborn, Kathleen R.; Prados, Michael D.; Berger, Mitchel S. [Department of Neurological Surgery and Brain Tumor Research Center, University of California-San Francisco, San Francisco, CA (United States); Wara, William M. [Department of Radiation Oncology, University of California-San Francisco, San Francisco, CA (United States); Haas-Kogan, Daphne A. [Department of Radiation Oncology, University of California-San Francisco, San Francisco, CA (United States); Department of Neurological Surgery and Brain Tumor Research Center, University of California-San Francisco, San Francisco, CA (United States)], E-mail: dhaaskogan@radonc.ucsf.edu

    2008-12-01

    Purpose: To review a historical cohort of pediatric patients with supratentorial primitive neuroectodermal tumors (sPNET), to clarify the role of radiation in the treatment of these tumors. Patients and Methods: Fifteen children aged <18 years with non-pineal sPNETs diagnosed between 1992 and 2006 were identified. Initial therapy consisted of surgical resection and chemotherapy in all patients and up-front radiotherapy (RT) in 5 patients. Five patients had RT at the time of progression, and 5 received no RT whatever. Kaplan-Meier estimates of overall survival were then calculated. Results: The median follow-up from diagnosis for all patients was 31 months (range, 0.5-165 months) and for surviving patients was 49 months (range, 10-165). Of the 5 patients who received up-front RT, all were alive without evidence of disease at a median follow-up of 50 months (range, 25-165 months). Only 5 of the 10 patients who did not receive up-front RT were alive at last follow-up. There was a statistically significant difference in overall survival between the patient group that received up-front RT and the group that did not (p = 0.048). In addition, we found a trend toward a statistically significant improvement in overall survival for those patients who received gross total resections (p = 0.10). Conclusions: Up-front RT and gross total resection may confer a survival benefit in patients with sPNET. Local failure was the dominant pattern of recurrence. Efforts should be made to determine patients most likely to have local failure exclusively or as a first recurrence, in order to delay or eliminate craniospinal irradiation.

  18. Persistence of the irradiated host component in thymocyte populations from bone marrow radiation chimeras infected with lymphocytic choriomeningitis virus

    SciTech Connect

    Lynch, F.; Ceredig, R.; Hartley, D.; Doherty, P.C.

    1989-02-01

    The thymus of chimeras made using T cell-depleted donor bone marrow from Thy1.1+ mice and 950 rad Thy 1.2+ recipients is dominated initially by cells expressing the Thy 1.2+ phenotype of the irradiated host. The thymocyte population recovered at 2 weeks after reconstitution comprises 80% Thy 1.2+ cells (host), the remainder being Thy 1.1+ (donor). This situation is normally reversed within a further week, with the host Ty 1.2+ (donor). This situation is normally reversed within a further week, with the host Thy 1.2+ thymocytes being present at a frequency of less than 5% from Week 4. Infection with lymphocytic choriomeningitis virus (LCMV) at 1 week after reconstitution with bone marrow causes a profound and persistent drop in the total number of thymocytes. The decline is equivalent for all categories of donor-derived thymocytes defined by two-color flow microfluorometric analysis for CD4 and CD8. However, there is a partial compensation by the retention of cells originating from the Thy 1.2+ host, which constitute 30-40% of the total thymocyte pool as late as 8 weeks after administration of bone marrow in the LCMV-infected chimeras. These radiation-resistant precursors give rise to CD4-8-, CD4-8+, CD4+8-, and CD4+8+ thymocytes, with the latter category being present at increased frequency. The potential skewing of the mature T cell repertoire as a consequence of persistent virus infection is discussed.

  19. Study of metallic components of historical organ pipes using synchrotron radiation X-ray microfluorescence imaging and grazing incidence X-ray diffraction.

    PubMed

    Herrera, L K; Justo, A; Muñoz-Páez, A; Sans, J A; Martínez-Criado, G

    2009-12-01

    A comparative study of the composition and microstructure of two different brass alloys from reed pipes, one from a Spanish baroque organ and the other from a modern one, was carried out. This study allowed us to determine the procedure followed to produce the brass used to make ancient reed pipes. Moreover the distribution and correlation of lead and other trace elements present into the main component of the brass, the copper and zinc phases, of the historical tongues and shallots were established. This chemical composition was compared with that of a tongue from a twentieth-century organ. The whole study was accomplished using a combination of laboratory and synchrotron radiation techniques. X-ray fluorescence was the technique used to obtain elemental and chemical imaging of the main phases and the trace elements at a sub-micrometer scale. PMID:19730830

  20. New BNL 3D-Trench Electrode Si Detectors for Radiation Hard Detectors for sLHC and for X-ray Applications

    SciTech Connect

    Li Z.

    2011-05-11

    A new international-patent-pending (PCT/US2010/52887) detector type, named here as 3D-Trench electrode Si detectors, is proposed in this work. In this new 3D electrode configuration, one or both types of electrodes are etched as trenches deep into the Si (fully penetrating with SOI or supporting wafer, or non-fully penetrating into 50-90% of the thickness), instead of columns as in the conventional ('standard') 3D electrode Si detectors. With trench etched electrodes, the electric field in the new 3D electrode detectors are well defined without low or zero field regions. Except near both surfaces of the detector, the electric field in the concentric type 3D-Trench electrode Si detectors is nearly radial with little or no angular dependence in the circular and hexangular (concentric-type) pixel cell geometries. In the case of parallel plate 3D trench pixels, the field is nearly linear (like the planar 2D electrode detectors), with simple and well-defined boundary conditions. Since each pixel cell in a 3D-Trench electrode detector is isolated from others by highly doped trenches, it is an electrically independent cell. Therefore, an alternative name 'Independent Coaxial Detector Array', or ICDA, is assigned to an array of 3D-Trench electrode detectors. The electric field in the detector can be reduced by a factor of nearly 10 with an optimal 3D-Trench configuration where the junction is on the surrounding trench side. The full depletion voltage in this optimal configuration can be up to 7 times less than that of a conventional 3D detector, and even a factor of two less than that of a 2D planar detector with a thickness the same as the electrode spacing in the 3D-Trench electrode detector. In the case of non-fully penetrating trench electrodes, the processing is true one-sided with backside being unprocessed. The charge loss due to the dead space associated with the trenches is insignificant as compared to that due to radiation-induced trapping in sLHC environment. Since the large electrode spacing (up to 500 {micro}m) can be realized in the 3D-Trench electrode detector due to their advantage of greatly reduced full depletion voltage, detectors with large pixel cells (therefore small dead volume) can be made for applications in photon science (e.g. X-ray).

  1. New BNL 3D-Trench electrode Si detectors for radiation hard detectors for sLHC and for X-ray applications

    NASA Astrophysics Data System (ADS)

    Li, Zheng

    2011-12-01

    A new international-patent-pending (PCT/US2010/52887) detector type, named here as 3D-Trench electrode Si detectors, is proposed in this work. In this new 3D electrode configuration, one or both types of electrodes are etched as trenches deep into the Si (fully penetrating with SOI or supporting wafer, or non-fully penetrating into 50-90% of the thickness), instead of columns as in the conventional ("standard") 3D electrode Si detectors. With trench etched electrodes, the electric field in the new 3D electrode detectors are well defined without low or zero field regions. Except near both surfaces of the detector, the electric field in the concentric type 3D-Trench electrode Si detectors is nearly radial with little or no angular dependence in the circular and hexangular (concentric-type) pixel cell geometries. In the case of parallel plate 3D trench pixels, the field is nearly linear (like the planar 2D electrode detectors), with simple and well-defined boundary conditions. Since each pixel cell in a 3D-Trench electrode detector is isolated from others by highly doped trenches, it is an electrically independent cell. Therefore, an alternative name "Independent Coaxial Detector Array", or ICDA, is assigned to an array of 3D-Trench electrode detectors. The electric field in the detector can be reduced by a factor of nearly 10 with an optimal 3D-Trench configuration where the junction is on the surrounding trench side. The full depletion voltage in this optimal configuration can be up to 7 times less than that of a conventional 3D detector, and even a factor of two less than that of a 2D planar detector with a thickness the same as the electrode spacing in the 3D-Trench electrode detector. In the case of non-fully penetrating trench electrodes, the processing is true one-sided with backside being unprocessed. The charge loss due to the dead space associated with the trenches is insignificant as compared to that due to radiation-induced trapping in sLHC environment. Since the large electrode spacing (up to 500 ?m) can be realized in the 3D-Trench electrode detector due to their advantage of greatly reduced full depletion voltage, detectors with large pixel cells (therefore small dead volume) can be made for applications in photon science (e.g. X-ray).

  2. The eCDR, a Radiation-Hard 40/80/160/320 Mbit/s CDR with internal VCO frequency calibration and 195 ps programmable phase resolution in 130 nm CMOS

    NASA Astrophysics Data System (ADS)

    Tavernier, F.; Francisco, R.; Bonacini, S.; Poltorak, K.; Moreira, P.

    2013-12-01

    A clock and data recovery IP, the eCDR, is presented which is intended to be implemented on the detector front-end ASICs that need to communicate with the GBTX by means of e-links. The programmable CDR accepts data at 40, 80, 160 or 320Mbit/s and generates retimed data as well as 40, 80, 160 and 320MHz clocks that are aligned to the retimed data. Moreover, all the outputs have a programmable phase with a resolution of 195ps. An internal calibration mechanism enables the eCDR to lock on incoming data even without the availability of any form of reference clock. The radiation-hard design, integrated in a 130nm CMOS technology, operates at a supply voltage between 1.2V and 1.5V. The power consumption is between 28.5mW and 34.5mW, depending on the settings. The eCDR can achieve a very low RMS jitter below 10ps.

  3. Radiation-Tolerant DC-DC Converters

    NASA Technical Reports Server (NTRS)

    Skutt, Glenn; Sable, Dan; Leslie, Leonard; Graham, Shawn

    2012-01-01

    A document discusses power converters suitable for space use that meet the DSCC MIL-PRF-38534 Appendix G radiation hardness level P classification. A method for qualifying commercially produced electronic parts for DC-DC converters per the Defense Supply Center Columbus (DSCC) radiation hardened assurance requirements was developed. Development and compliance testing of standard hybrid converters suitable for space use were completed for missions with total dose radiation requirements of up to 30 kRad. This innovation provides the same overall performance as standard hybrid converters, but includes assurance of radiation- tolerant design through components and design compliance testing. This availability of design-certified radiation-tolerant converters can significantly reduce total cost and delivery time for power converters for space applications that fit the appropriate DSCC classification (30 kRad).

  4. How Hard is Chocolate?

    NSDL National Science Digital Library

    2007-12-20

    Hardness is probably a concept you are well familiar with. You already know that certain materials are harder than others; in fact, you prove it everyday when you chew your food and your teeth don’t break (because your teeth are harder than the foods you chew). Hardness can be defined as a material's ability to resist a change in shape. Modern hardness testers take a well-defined shape and press it into a material with a certain force, observing the indent it leaves in the material when it is removed. In this lesson, you will be performing hardness testing on different bars of chocolate.

  5. HARD BREMSSTRAHLUNG PHOTONS FROM GRAVITON EXCHANGE

    E-print Network

    HARD BREMSSTRAHLUNG PHOTONS FROM GRAVITON EXCHANGE #3; LC-TH-2004-015 T. BUANES, E.W. DVERGSNES Abstract We review photon Bremsstrahlung in extra-dimensional models with massive gravitons. The photon spectrum is harder than in the Standard Model. In the RS scenario, radiative return to gravitons below

  6. Ordering of hard particles between hard walls

    NASA Astrophysics Data System (ADS)

    Chrzanowska, A.; Teixeira, P. I. C.; Ehrentraut, H.; Cleaver, D. J.

    2001-05-01

    The structure of a fluid of hard Gaussian overlap particles of elongation ? = 5, confined between two hard walls, has been calculated from density-functional theory and Monte Carlo simulations. By using the exact expression for the excluded volume kernel (Velasco E and Mederos L 1998 J. Chem. Phys. 109 2361) and solving the appropriate Euler-Lagrange equation entirely numerically, we have been able to extend our theoretical predictions into the nematic phase, which had up till now remained relatively unexplored due to the high computational cost. Simulation reveals a rich adsorption behaviour with increasing bulk density, which is described semi-quantitatively by the theory without any adjustable parameters.

  7. Hard X-rays from Coma Cluster region

    SciTech Connect

    Bazzano, A.; Fusco-Femiano, R.; Ubertini, P.; Perotti, F.; Quadrini, E. (CNR, Istituto di Astrofisica Spaziale, Frascati (Italy) CNR, Istituto di Fisica Cosmica, Milan (Italy))

    1990-10-01

    A high-energy nonthermal component in the 18-130 keV energy band was detected by balloon-borne observations of the region containing the Coma Cluster of galaxies. The emitted photon spectrum is well-described by a single power law of photon index -1.77 and an intensity of 8.9 x 10 to the -5th photons/sq cm/s/KeV at 50 keV. The emission supports the presence of a hard tail, and could be due to the inverse Compton mechanism of relativistic electrons permeating the cluster off the 2.7 K background radiation or the presence in the field of an active galactic nucleus. 30 refs.

  8. Session: Hard Rock Penetration

    SciTech Connect

    Tennyson, George P. Jr.; Dunn, James C.; Drumheller, Douglas S.; Glowka, David A.; Lysne, Peter

    1992-01-01

    This session at the Geothermal Energy Program Review X: Geothermal Energy and the Utility Market consisted of five presentations: ''Hard Rock Penetration - Summary'' by George P. Tennyson, Jr.; ''Overview - Hard Rock Penetration'' by James C. Dunn; ''An Overview of Acoustic Telemetry'' by Douglas S. Drumheller; ''Lost Circulation Technology Development Status'' by David A. Glowka; ''Downhole Memory-Logging Tools'' by Peter Lysne.

  9. Hardness Tester for Polyur

    NASA Technical Reports Server (NTRS)

    Hauser, D. L.; Buras, D. F.; Corbin, J. M.

    1987-01-01

    Rubber-hardness tester modified for use on rigid polyurethane foam. Provides objective basis for evaluation of improvements in foam manufacturing and inspection. Typical acceptance criterion requires minimum hardness reading of 80 on modified tester. With adequate correlation tests, modified tester used to measure indirectly tensile and compressive strengths of foam.

  10. Hard diffraction in CDF

    SciTech Connect

    K. Terashi

    2002-07-12

    We present Run I results on hard diffraction obtained by the CDF Collaboration in proton-antiproton collisions at the Fermilab Tevatron. They are compared with results from the DESY ep collider HERA and/or theoretical predictions to test factorization in hard diffraction. In addition, the CDF program for diffractive studies in Run II is presented briefly.

  11. Scintillation fibers and nanoscintillators for improving the spatial, spectrometric, and time resolution of radiation detectors

    Microsoft Academic Search

    N. V. Klassen; V. N. Kurlov; S. N. Rossolenko; O. A. Krivko; A. D. Orlov; S. Z. Shmurak

    2009-01-01

    Experimental examples demonstrate a significant improvement of the most important parameters (sensitivity; spatial, spectrometric,\\u000a and time resolution; and radiation hardness) of radiation detectors with sensitive elements based on fiber and nanocrystalline\\u000a scintillators instead of conventional bulk single crystals. This improvement is related to several specific features of the\\u000a new scintillator types: improved homogeneity of activator distribution, larger soft X-ray component

  12. Diffuse hard X-ray and gamma-ray emission from M87

    NASA Technical Reports Server (NTRS)

    Dermer, Charles D.; Rephaeli, Yoel

    1988-01-01

    Radio measurements are used to infer the relativistic electron distributions in the central and halo regions of M87. From these distributions and the inferred relativistic proton components, the hard X-ray and gamma-ray spectrum of M87, is predicted, taking into account all relevant radiative processes. The feasibility of measuring the high-energy spectrum of M87 with the High Energy Gamma-Ray Telescope (Egret) on board the Gamma Ray Observatory (GRO) is discussed. Comparison of our calculation with present gamma-ray flux upper limits leads to a lower limit of 1.5 micro-G on the mean value of the halo magnetic field.

  13. Hard sphere mixtures near a hard wall

    Microsoft Academic Search

    JERZY P. NOWORYTA; DOUGLAS HENDERSON; STEFAN SOKO?OWSKI; KWONG-YU CHAN

    1998-01-01

    Hard spheres with ratios of diameters of 3:5 and 1:3 and at various densities are studied by means of grand canonical ensemble (GCE) simulations, first- and second-order Percus—Yevick theory, scaled particle theory (SPT) and density functional theory (DFT). Generally, but not always, the density profiles of the first-order Percus—Yevick (PY1) theory results are smaller at contact than the GCE simulation

  14. Hard Incoherent Radiation in Thick Crystals

    Microsoft Academic Search

    N. F. Shul'Ga; V. V. Syshchenko; A. I. Tarnovsky

    2010-01-01

    The particle flux redistribution in oriented crystals leads to arising of various orientation effects in the yields of processes connected to small impact parameters (nuclear reactions, knocking out delta-electrons etc). Orientation effects of that type in the incoherent bremsstrahlung were discussed earlier in several experimental and theoretical articles. In this paper we present some improved and new results obtained using

  15. Statistical Modeling for Radiation Hardness Assurance

    NASA Technical Reports Server (NTRS)

    Ladbury, Raymond L.

    2014-01-01

    We cover the models and statistics associated with single event effects (and total ionizing dose), why we need them, and how to use them: What models are used, what errors exist in real test data, and what the model allows us to say about the DUT will be discussed. In addition, how to use other sources of data such as historical, heritage, and similar part and how to apply experience, physics, and expert opinion to the analysis will be covered. Also included will be concepts of Bayesian statistics, data fitting, and bounding rates.

  16. TEMPORAL AND SPECTRAL EVOLUTION IN X- AND {gamma}-RAYS OF MAGNETAR 1E 1547.0-5408 SINCE ITS 2008 OCTOBER OUTBURST: THE DISCOVERY OF A TRANSIENT HARD PULSED COMPONENT AFTER ITS 2009 JANUARY OUTBURST

    SciTech Connect

    Kuiper, L.; Hermsen, W. [SRON-National Institute for Space Research, Sorbonnelaan 2, 3584 CA, Utrecht (Netherlands); Den Hartog, P. R. [Stanford University HEPL/KIPAC Physics, 382 via Pueblo Mall Stanford, CA 94305 (United States); Urama, J. O., E-mail: L.M.Kuiper@sron.nl [Department of Physics and Astronomy, University of Nigeria, Nsukka (Nigeria)

    2012-04-01

    The magnetar 1E 1547.0-5408 exhibited outbursts in 2008 October and 2009 January. In this paper, we present in great detail the evolution of the temporal and spectral characteristics of the persistent total and pulsed emission of 1E 1547.0-5408 between {approx}1 and 300 keV starting on 2008 October 3 and ending in 2011 January. We analyzed data collected with the Rossi X-ray Timing Explorer (RXTE) the International Gamma-Ray Astrophysics Laboratory (INTEGRAL), and the Swift satellite. We report the evolution of the pulse frequency, and the measurement at the time of the onset of the 2009 January outburst of an insignificant jump in frequency, but a major frequency derivative jump {Delta}{nu}-dot of +(1.30 {+-} 0.14) Multiplication-Sign 10{sup -11} Hz s{sup -1} ({Delta}{nu}-dot/{nu}-dot of -0.69 {+-} 0.07). Before this {nu}-dot glitch, a single broad pulse is detected, mainly for energies below {approx}10 keV. Surprisingly, {approx}11 days after the glitch a new transient high-energy (up to {approx}150 keV) pulse appears with a Gaussian shape and width 0.23, shifted in phase by {approx}0.31 compared to the low-energy pulse, which smoothly fades to undetectable levels in {approx}350 days. We report the evolution of the pulsed-emission spectra. For energies 2.5-10 keV all pulsed spectra are very soft with photon indices {Gamma} between -4.6 and -3.9. For {approx}10-150 keV, after the {nu}-dot glitch, we report hard non-thermal pulsed spectra, similar to what has been reported for the persistent pulsed emission of some anomalous X-ray pulsars. This pulsed hard X-ray emission reached maximal luminosity 70 {+-} 30 days after the glitch epoch, followed by a gradual decrease by more than a factor of 10 over {approx}300 days. These characteristics differ from those of the total emission. Both, the total soft X-ray (1-10 keV) and hard X-ray (10-150 keV) fluxes, were maximal already 2 days after the 2009 January outburst, and decayed by a factor of {approx}>3 over {approx}400 days. The total spectra can be described with a blackbody (kT values varying in the range 0.57-0.74 keV) plus a single power-law model. The photon index exhibited a hardening ({approx} - 1.4 to {approx} - 0.9) with time, correlated with a decrease in flux in the 20-300 keV band. We discuss these findings in the framework of the magnetar model.

  17. AMORPHOUS ALLOY SURFACE COATINGS FOR HARD CHROMIUM REPLACEMENT - PHASE I

    EPA Science Inventory

    Hard chromium coatings (0.25 to10 mil thick) are used extensively for imparting wear and erosion resistance to components in both industrial and military applications. The most common means of depositing hard chromium has been through the use of chromic acid baths containing ...

  18. Spin and hard processes

    E-print Network

    P. Kroll

    2002-10-16

    It is argued that spin is a fundamental aspect of gauge theories at short distances. As a consequence there are characteristic helicity asymmetries in hard inclusive and exclusive reactions of which a few are discussed.

  19. A Hard X-Ray Power-law Spectral Cutoff in Centaurus X-4

    NASA Astrophysics Data System (ADS)

    Chakrabarty, Deepto; Tomsick, John A.; Grefenstette, Brian W.; Psaltis, Dimitrios; Bachetti, Matteo; Barret, Didier; Boggs, Steven E.; Christensen, Finn E.; Craig, William W.; Fürst, Felix; Hailey, Charles J.; Harrison, Fiona A.; Kaspi, Victoria M.; Miller, Jon M.; Nowak, Michael A.; Rana, Vikram; Stern, Daniel; Wik, Daniel R.; Wilms, Jörn; Zhang, William W.

    2014-12-01

    The low-mass X-ray binary (LMXB) Cen X-4 is the brightest and closest (<1.2 kpc) quiescent neutron star transient. Previous 0.5-10 keV X-ray observations of Cen X-4 in quiescence identified two spectral components: soft thermal emission from the neutron star atmosphere and a hard power-law tail of unknown origin. We report here on a simultaneous observation of Cen X-4 with NuSTAR (3-79 keV) and XMM-Newton (0.3-10 keV) in 2013 January, providing the first sensitive hard X-ray spectrum of a quiescent neutron star transient. The 0.3-79 keV luminosity was 1.1× 1033 D^2_kpc erg s-1, with sime60% in the thermal component. We clearly detect a cutoff of the hard spectral tail above 10 keV, the first time such a feature has been detected in this source class. We show that thermal Comptonization and synchrotron shock origins for the hard X-ray emission are ruled out on physical grounds. However, the hard X-ray spectrum is well fit by a thermal bremsstrahlung model with kTe = 18 keV, which can be understood as arising either in a hot layer above the neutron star atmosphere or in a radiatively inefficient accretion flow. The power-law cutoff energy may be set by the degree of Compton cooling of the bremsstrahlung electrons by thermal seed photons from the neutron star surface. Lower thermal luminosities should lead to higher (possibly undetectable) cutoff energies. We compare Cen X-4's behavior with PSR J1023+0038, IGR J18245-2452, and XSS J12270-4859, which have shown transitions between LMXB and radio pulsar modes at a similar X-ray luminosity.

  20. Radiation Processing -an overview

    E-print Network

    1 Radiation Processing - an overview Arne Miller Risø High Dose Reference Laboratory Risø DTU DK of radiation · Facilities ­ Gamma ­ electrons ­ X-ray ­ Safety · Sterilisation of medical devices · Food ­ radiation hardness testing ­ semiconductors ­ microlitography ­ gem stones · Dosimetry · Quality assurance

  1. The Effect of Total Ionizing Dose Degradation of Laptop Hard Disks

    NASA Technical Reports Server (NTRS)

    Nguyen, D. N.; Guertin, S. M.; Patterson, J. D.

    2005-01-01

    A series of total ionizing dose (TID) measurements were performed on commercial hard drives to explore the possible uses of the devices for the high radiation mission, and to help the understanding of the reliability of current hard drive technology. Three different models from three major manufacturers were tested with the aid of a commercial hard drive test system.

  2. Structural building component

    Microsoft Academic Search

    Hollobaugh

    1981-01-01

    A structural building component having an elongated trough like shell with side walls of adjacent components held together by a clamping means that prevents leakage between the panels and hold the panels against endwise movement relative to each other. The panels include solar radiation absorbing means and heat transfer means in the form of tubes which extend completely through the

  3. Hard X-Ray Emission from the Galaxy Cluster A2256

    NASA Astrophysics Data System (ADS)

    Fusco-Femiano, Roberto; Dal Fiume, Daniele; De Grandi, Sabrina; Feretti, Luigina; Giovannini, Gabriele; Grandi, Paola; Malizia, Angela; Matt, Giorgio; Molendi, Silvano

    2000-05-01

    After the positive detection by BeppoSAX of hard X-ray radiation up to ~80 keV in the Coma Cluster spectrum, we present evidence for nonthermal emission from A2256 in excess of thermal emission at a 4.6 ? confidence level. In addition to this power-law component, a second nonthermal component already detected by ASCA could be present in the X-ray spectrum of the cluster, which is not surprising given the complex radio morphology of the cluster central region. The spectral index of the hard tail detected by the Phoswich Detection System on board BeppoSAX is marginally consistent with that expected for the inverse Compton model. A value of ~0.05 ?G is derived for the intracluster magnetic field of the extended radio emission in the northern regions of the cluster, while a higher value of ~0.5 ?G could be present in the central radio halo, which is likely related to the hard tail detected by ASCA.

  4. Hard X-Ray Emission from the Galaxy Cluster A2256.

    PubMed

    Fusco-Femiano; Dal Fiume D; De Grandi S; Feretti; Giovannini; Grandi; Malizia; Matt; Molendi

    2000-05-01

    After the positive detection by BeppoSAX of hard X-ray radiation up to approximately 80 keV in the Coma Cluster spectrum, we present evidence for nonthermal emission from A2256 in excess of thermal emission at a 4.6 sigma confidence level. In addition to this power-law component, a second nonthermal component already detected by ASCA could be present in the X-ray spectrum of the cluster, which is not surprising given the complex radio morphology of the cluster central region. The spectral index of the hard tail detected by the Phoswich Detection System on board BeppoSAX is marginally consistent with that expected for the inverse Compton model. A value of approximately 0.05 µG is derived for the intracluster magnetic field of the extended radio emission in the northern regions of the cluster, while a higher value of approximately 0.5 µG could be present in the central radio halo, which is likely related to the hard tail detected by ASCA. PMID:10790058

  5. Erosion testing of hard materials and coatings

    SciTech Connect

    Hawk, Jeffrey A.

    2005-04-29

    Erosion is the process by which unconstrained particles, usually hard, impact a surface, creating damage that leads to material removal and component failure. These particles are usually very small and entrained in fluid of some type, typically air. The damage that occurs as a result of erosion depends on the size of the particles, their physical characteristics, the velocity of the particle/fluid stream, and their angle of impact on the surface of interest. This talk will discuss the basics of jet erosion testing of hard materials, composites and coatings. The standard test methods will be discussed as well as alternative approaches to determining the erosion rate of materials. The damage that occurs will be characterized in genera1 terms, and examples will be presented for the erosion behavior of hard materials and coatings (both thick and thin).

  6. Nonvolatile Rad-Hard Holographic Memory

    NASA Technical Reports Server (NTRS)

    Chao, Tien-Hsin; Zhou, Han-Ying; Reyes, George; Dragoi, Danut; Hanna, Jay

    2001-01-01

    We are investigating a nonvolatile radiation-hardened (rad-hard) holographic memory technology. Recently, a compact holographic data storage (CHDS) breadboard utilizing an innovative electro-optic scanner has been built and demonstrated for high-speed holographic data storage and retrieval. The successful integration of this holographic memory breadboard has paved the way for follow-on radiation resistance test of the photorefractive (PR) crystal, Fe:LiNbO3. We have also started the investigation of using two-photon PR crystals that are doubly doped with atoms of iron group (Ti, Cr, Mn, Cu) and of rare-earth group (Nd, Tb) for nonvolatile holographic recordings.

  7. Dissecting soft radiation with factorization.

    PubMed

    Stewart, Iain W; Tackmann, Frank J; Waalewijn, Wouter J

    2015-03-01

    An essential part of high-energy hadronic collisions is the soft hadronic activity that underlies the primary hard interaction. It includes soft radiation from the primary hard partons, secondary multiple parton interactions (MPI), and factorization-violating effects. The invariant mass spectrum of the leading jet in Z+jet and H+jet events is directly sensitive to these effects, and we use a QCD factorization theorem to predict its dependence on the jet radius R, jet p_{T}, jet rapidity, and partonic process for both the perturbative and nonperturbative components of primary soft radiation. We prove that the nonperturbative contributions involve only odd powers of R, and the linear R term is universal for quark and gluon jets. The hadronization model in Pythia8 agrees well with these properties. The perturbative soft initial state radiation (ISR) has a contribution that depends on the jet area in the same way as the underlying event, but this degeneracy is broken by dependence on the jet p_{T}. The size of this soft ISR contribution is proportional to the color state of the initial partons, yielding the same positive contribution for gg?Hg and gq?Zq, but a negative interference contribution for qq[over ¯]?Zg. Hence, measuring these dependencies allows one to separate hadronization, soft ISR, and MPI contributions in the data. PMID:25793802

  8. Dissecting Soft Radiation with Factorization

    NASA Astrophysics Data System (ADS)

    Stewart, Iain W.; Tackmann, Frank J.; Waalewijn, Wouter J.

    2015-03-01

    An essential part of high-energy hadronic collisions is the soft hadronic activity that underlies the primary hard interaction. It includes soft radiation from the primary hard partons, secondary multiple parton interactions (MPI), and factorization-violating effects. The invariant mass spectrum of the leading jet in Z +jet and H +jet events is directly sensitive to these effects, and we use a QCD factorization theorem to predict its dependence on the jet radius R , jet pT, jet rapidity, and partonic process for both the perturbative and nonperturbative components of primary soft radiation. We prove that the nonperturbative contributions involve only odd powers of R , and the linear R term is universal for quark and gluon jets. The hadronization model in Pythia8 agrees well with these properties. The perturbative soft initial state radiation (ISR) has a contribution that depends on the jet area in the same way as the underlying event, but this degeneracy is broken by dependence on the jet pT . The size of this soft ISR contribution is proportional to the color state of the initial partons, yielding the same positive contribution for g g ?H g and g q ?Z q , but a negative interference contribution for q q ¯ ?Z g . Hence, measuring these dependencies allows one to separate hadronization, soft ISR, and MPI contributions in the data.

  9. CSI: Hard Drive

    ERIC Educational Resources Information Center

    Sturgeon, Julie

    2008-01-01

    Acting on information from students who reported seeing a classmate looking at inappropriate material on a school computer, school officials used forensics software to plunge the depths of the PC's hard drive, searching for evidence of improper activity. Images were found in a deleted Internet Explorer cache as well as deleted file space.…

  10. Hardness vs Randomness

    Microsoft Academic Search

    Noam Nisan; Avi Wigderson

    1994-01-01

    We present a simple ne wc onstruction of a pseudorandom bit generator ,b ased on the constant depth generators of (N). It stretches a short string of truly random bits into a long string that looks random to an ya lgorithm from a comple xity class C (eg P, NC, PSPACE, ... )u sing an arbitrary function that is hard

  11. Hard Times Hit Schools

    ERIC Educational Resources Information Center

    McNeil, Michele

    2008-01-01

    Hard-to-grasp dollar amounts are forcing real cuts in K-12 education at a time when the cost of fueling buses and providing school lunches is increasing and the demands of the federal No Child Left Behind Act still loom larger over states and districts. "One of the real challenges is to continue progress in light of the economy," said Gale Gaines,…

  12. Budgeting in Hard Times.

    ERIC Educational Resources Information Center

    Parrino, Frank M.

    2003-01-01

    Interviews with school board members and administrators produced a list of suggestions for balancing a budget in hard times. Among these are changing calendars and schedules to reduce heating and cooling costs; sharing personnel; rescheduling some extracurricular activities; and forming cooperative agreements with other districts. (MLF)

  13. Work Hard. Be Nice

    ERIC Educational Resources Information Center

    Mathews, Jay

    2009-01-01

    In 1994, fresh from a two-year stint with Teach for America, Mike Feinberg and Dave Levin inaugurated the Knowledge Is Power Program (KIPP) in Houston with an enrollment of 49 5th graders. By this Fall, 75 KIPP schools will be up and running, setting children from poor and minority families on a path to college through a combination of hard work,…

  14. Radiation-damage studies, irradiations and high-dose dosimetry for LHC detectors

    E-print Network

    Coninckx, F; León-Florián, E; Leutz, H; Schönbacher, Helmut; Sonderegger, P; Tavlet, Marc; Sopko, B; Henschel, H; Schmidt, H U; Boden, A; Bräunig, D; Wulf, F; Cramariuc, R; Ilie, D; Fattibene, P; Onori, S; Miljanic, S; Paic, G; Razen, B; Razem, D; Rendic, D; CERN. Geneva. Detector Research and Development Committee

    1991-01-01

    The proposal is divided into a main project and special projects. The main project consists of a service similar to the one given in the past to accelerator construction projects at CERN (ISR,SPS,LEP) on high-dose dosimetry, material irradiations, irradiations tests, standardization of test procedures and data compilations. Large experience in this field and numerous radiation damage test data of insulating and structural materials are available. The special projects cover three topics which are of specific interest for LHC detector physicists and engineers at CERN and in other high energy physics institutes, namely: Radiation effects in scintillators; Selection of radiation hard optical fibres for data transmission; and Selection and testing of radiation hard electronic components.

  15. The Space Radiation Environment as it Relates to Electronic System Performance: Or Why Not to Fly Commercial Electronic Components in Space

    NASA Technical Reports Server (NTRS)

    Barth, Janet L.; Xapsos, Michael A.; LaBel, Kenneth A.; Polvey, Christian

    2005-01-01

    This viewgraph presentation offers an overview of the space radiation environment, primarily in near-Earth environments such as Low Earth Orbit (LEO). The presentation describes the Halloween solar event of 2003 as an example of how solar activity can affect spacecraft electronic systems. The lunar radiation environment is also briefly summarized.

  16. Style Components

    Microsoft Academic Search

    Ari Shapiro Yong; Petros Faloutsosá

    We propose a novel method for interactive editing of motion data based on motion decomposition. Our method employs Independent Component Analysis (ICA) to separate motion data into visually meaningful components called style components. The user then interactively identies suitable style components and manipulates them based on a proposed set of operations. In particular, the user can transfer style components from

  17. Hard-on-Hard Lubrication in the Artificial Hip under Dynamic Loading Conditions

    PubMed Central

    Sonntag, Robert; Reinders, Jörn; Rieger, Johannes S.; Heitzmann, Daniel W. W.; Kretzer, J. Philippe

    2013-01-01

    The tribological performance of an artificial hip joint has a particularly strong influence on its success. The principle causes for failure are adverse short- and long-term reactions to wear debris and high frictional torque in the case of poor lubrication that may cause loosening of the implant. Therefore, using experimental and theoretical approaches models have been developed to evaluate lubrication under standardized conditions. A steady-state numerical model has been extended with dynamic experimental data for hard-on-hard bearings used in total hip replacements to verify the tribological relevance of the ISO 14242-1 gait cycle in comparison to experimental data from the Orthoload database and instrumented gait analysis for three additional loading conditions: normal walking, climbing stairs and descending stairs. Ceramic-on-ceramic bearing partners show superior lubrication potential compared to hard-on-hard bearings that work with at least one articulating metal component. Lubrication regimes during the investigated activities are shown to strongly depend on the kinematics and loading conditions. The outcome from the ISO gait is not fully confirmed by the normal walking data and more challenging conditions show evidence of inferior lubrication. These findings may help to explain the differences between the in vitro predictions using the ISO gait cycle and the clinical outcome of some hard-on-hard bearings, e.g., using metal-on-metal. PMID:23940772

  18. A radiation-hardened star scanner for spacecraft guidance and control

    NASA Technical Reports Server (NTRS)

    Birnbaum, M. M.; Bunker, R. L.; Tavolacci, J. T.

    1981-01-01

    A star scanner for the Galileo Project is described. Because it must function in the intense Jupiter radiation field, which consists primarily of high-energy electrons and protons, this star scanner is designed with radiation-hardness as a prime objective. The optics and the multiplier phototube are specially designed to minimize fluorescence and Cerenkov effects, and the electronic components to minimize ionization and displacement damage. The star-scanner layout provides maximum shielding for the optics and phototube. Test results predict successful operation in the expected Jovian radiation environment.

  19. Hard and soft acids and bases: structure and process.

    PubMed

    Reed, James L

    2012-07-01

    Under investigation is the structure and process that gives rise to hard-soft behavior in simple anionic atomic bases. That for simple atomic bases the chemical hardness is expected to be the only extrinsic component of acid-base strength, has been substantiated in the current study. A thermochemically based operational scale of chemical hardness was used to identify the structure within anionic atomic bases that is responsible for chemical hardness. The base's responding electrons have been identified as the structure, and the relaxation that occurs during charge transfer has been identified as the process giving rise to hard-soft behavior. This is in contrast the commonly accepted explanations that attribute hard-soft behavior to varying degrees of electrostatic and covalent contributions to the acid-base interaction. The ability of the atomic ion's responding electrons to cause hard-soft behavior has been assessed by examining the correlation of the estimated relaxation energies of the responding electrons with the operational chemical hardness. It has been demonstrated that the responding electrons are able to give rise to hard-soft behavior in simple anionic bases. PMID:22668421

  20. Eat Smart. Play Hard.

    NSDL National Science Digital Library

    The Food and Nutrition Service of the US Department of Agriculture offers online educational material as part of "Eat Smart. Play Hard." -- a public information campaign designed to promote healthy living in American children. While the site and its materials are geared for use by state and local program coordinators, anyone is welcome to download the available information and activity sheets. Click on Cool Stuff for Kids for nutrition-related puzzles and games. Parents Place offers informational brochures and an educational bookmark.

  1. SUPER HARD SURFACED POLYMERS

    SciTech Connect

    Mansur, Louis K [ORNL] [ORNL; Bhattacharya, R [UES, Incorporated, Dayton, OH] [UES, Incorporated, Dayton, OH; Blau, Peter Julian [ORNL] [ORNL; Clemons, Art [ORNL] [ORNL; Eberle, Cliff [ORNL] [ORNL; Evans, H B [UES, Incorporated, Dayton, OH] [UES, Incorporated, Dayton, OH; Janke, Christopher James [ORNL] [ORNL; Jolly, Brian C [ORNL] [ORNL; Lee, E H [Consultant, Milpitas, CA] [Consultant, Milpitas, CA; Leonard, Keith J [ORNL] [ORNL; Trejo, Rosa M [ORNL] [ORNL; Rivard, John D [ORNL] [ORNL

    2010-01-01

    High energy ion beam surface treatments were applied to a selected group of polymers. Of the six materials in the present study, four were thermoplastics (polycarbonate, polyethylene, polyethylene terephthalate, and polystyrene) and two were thermosets (epoxy and polyimide). The particular epoxy evaluated in this work is one of the resins used in formulating fiber reinforced composites for military helicopter blades. Measures of mechanical properties of the near surface regions were obtained by nanoindentation hardness and pin on disk wear. Attempts were also made to measure erosion resistance by particle impact. All materials were hardness tested. Pristine materials were very soft, having values in the range of approximately 0.1 to 0.5 GPa. Ion beam treatment increased hardness by up to 50 times compared to untreated materials. For reference, all materials were hardened to values higher than those typical of stainless steels. Wear tests were carried out on three of the materials, PET, PI and epoxy. On the ion beam treated epoxy no wear could be detected, whereas the untreated material showed significant wear.

  2. Microcircuit radiation effects databank

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Radiation test data submitted by many testers is collated to serve as a reference for engineers who are concerned with and have some knowledge of the effects of the natural radiation environment on microcircuits. Total dose damage information and single event upset cross sections, i.e., the probability of a soft error (bit flip) or of a hard error (latchup) are presented.

  3. Flank wear prediction of ceramic tools in hard turning

    Microsoft Academic Search

    Dilbag Singh; P. Venkateswara Rao

    2010-01-01

    Due to technical and economical factors, hard turning is competing successfully with the grinding process in the industries.\\u000a Many practical applications require components to be hardened in order to improve their wear behavior. Higher productivity\\u000a and good surface quality are the requirements of the modern industries. However, tool wear is the major problem in hard turning.\\u000a The tool wear models,

  4. Self-diffusion in liquid gallium and hard sphere model

    NASA Astrophysics Data System (ADS)

    Blagoveshchenskii, Nikolay; Novikov, Arkady; Puchkov, Alexander; Savostin, Vadim; Sobolev, Oleg

    2015-01-01

    Incoherent and coherent components of quasielastic neutron scattering have been studied in the temperature range of T = 313 K - 793 K aiming to explore the applicability limits of the hard-sphere approach for the microscopic dynamics of liquid gallium, which is usually considered as a non-hard-sphere system. It was found that the non-hard-sphere effects come into play at the distances shorter than the average interatomic distance. The longer range diffusive dynamics of liquid Ga is dominated by the repulsive forces between the atoms.

  5. Hardness of Materials- Introduction

    NSDL National Science Digital Library

    This lesson plan from Edmonds Community College will serve as an excellent introduction to the hardness of materials. The module illustrates the differences in properties between different materials. Students will determine property differences between different types of materials, observe property differences between materials of the same class, measure, record and report their results and observe differences in results due to operator error. Student, instructor and course evaluation questions are included. This document will serve as a framework for instructors and may be downloaded in PDF format.

  6. Hard metal composition

    DOEpatents

    Sheinberg, Haskell (Los Alamos, NM)

    1986-01-01

    A composition of matter having a Rockwell A hardness of at least 85 is formed from a precursor mixture comprising between 3 and 10 weight percent boron carbide and the remainder a metal mixture comprising from 70 to 90 percent tungsten or molybdenum, with the remainder of the metal mixture comprising nickel and iron or a mixture thereof. The composition has a relatively low density of between 7 to 14 g/cc. The precursor is preferably hot pressed to yield a composition having greater than 100% of theoretical density.

  7. Hard physics in PHENIX

    E-print Network

    D. Peressounko; for the PHENIX collaboration

    2005-12-08

    We review recent results on hard observables in p+p, d+A and A+A collisions obtained by the PHENIX experiment. Emphasis is put on those measurements that provide insight into the properties of hot QCD media expected to be created in nucleus-nucleus collisions at RHIC energies. Direct photon spectra, jet properties and heavy quarks production measured in p+p and d+Au collisions are compared to the same observables extracted in heavy ion collisions to find modifications due to the presence of hot QCD matter.

  8. Hard diffraction in CDF

    SciTech Connect

    Albrow, M.G.; CDF Collaboration

    1997-10-01

    The aim of these studies is to use hard (large Q{sup 2}) processes to investigate the partonic nature of the pomeron. We have measured events with large rapidity gaps between balancing high E{sub T} jets, events with two forward (same-side) jets and a large gap (diffractive di-jet production), diffractive W{sup {+-}} production and diffractive heavy flavor (J/{psi} and b-quark) production. Candidate events of the type double-pomeron {yields} di-jet are observed. I close with a look at the future (Run II).

  9. Colony-stimulating factors for the treatment of the hematopoietic component of the acute radiation syndrome (H-ARS): a review.

    PubMed

    Singh, Vijay K; Newman, Victoria L; Seed, Thomas M

    2015-01-01

    One of the greatest national security threats to the United States is the detonation of an improvised nuclear device or a radiological dispersal device in a heavily populated area. As such, this type of security threat is considered to be of relatively low risk, but one that would have an extraordinary high impact on health and well-being of the US citizenry. Psychological counseling and medical assessments would be necessary for all those significantly impacted by the nuclear/radiological event. Direct medical interventions would be necessary for all those individuals who had received substantial radiation exposures (e.g., >1 Gy). Although no drugs or products have yet been specifically approved by the United States Food and Drug Administration (US FDA) to treat the effects of acute radiation syndrome (ARS), granulocyte colony-stimulating factor (G-CSF), granulocyte macrophage colony-stimulating factor (GM-CSF), and pegylated G-CSF have been used off label for treating radiation accident victims. Recent threats of terrorist attacks using nuclear or radiologic devices makes it imperative that the medical community have up-to-date information and a clear understanding of treatment protocols using therapeutically effective recombinant growth factors and cytokines such as G-CSF and GM-CSF for patients exposed to injurious doses of ionizing radiation. Based on limited human studies with underlying biology, we see that the recombinants, G-CSF and GM-CSF appear to have modest, but significant medicinal value in treating radiation accident victims. In the near future, the US FDA may approve G-CSF and GM-CSF as ‘Emergency Use Authorization’ (EUA) for managing radiation-induced aplasia, an ARS-related pathology. In this article, we review the status of growth factors for the treatment of radiological/nuclear accident victims. PMID:25215458

  10. CONTROL OF LASER RADIATION PARAMETERS: Generation of Stark spectral components in Nd:YAP and Nd:YAG lasers by using volume Bragg gratings

    NASA Astrophysics Data System (ADS)

    Vorob'ev, Nikolai S.; Glebov, L. B.; Smirnov, V. I.; Chapurin, I. V.

    2009-01-01

    Generation of Stark spectral components in free-running Q-switched Nd:YAP (1064 nm and 1073 nm) and Nd:YAG (1062 nm) lasers is obtained. For this purpose reflecting volume Bragg gratings placed into the laser resonator and permitting to tune the laser emission spectrum were used. Stable generation of Stark components in both lasers is obtained. The possibility of obtaining two-frequency generation in an Nd-glass laser with the help of these gratings is shown.

  11. Estimation of global solar radiation in Nigeria using a modified Angstrom model and the trend analysis of the allied meteorological components

    NASA Astrophysics Data System (ADS)

    Ogolo, E. O.

    2014-06-01

    The trend of some common and related atmospheric variables were investigated in the light of climate change on annual time scale and a suitable scheme was further developed for the simulation of annual global solar radiation in Nigeria. In this connection, annual trends of global solar radiation, air temperature, precipitation, relative humidity and sunshine hours was carried out, covering about 13 tropical stations during 1975-2006 in Nigeria using F-test as the significance test technique. It was found that nine stations exhibited an upward trend in global solar radiation series, of which 6 passed F-test at 1% significant level. At 11 stations, precipitation had shown an increasing trends but none passed F-test at 2.5% and hence, not significant. About 98.8% of the stations displayed an upward trend in sunshine hours of which 16% passed F-test at 1% significant level. On trend analysis for relative humidity series, eight stations exhibited a positive trend and only one station passed F-test at 1% significant level. The trend of temperature series in Nigeria under the period under investigation was found to be increasing at 12 stations and eight stations passed the F-test at 1% significant level. The other objective of this study was to determine a more suitable empirical equation by modifying Angstrom model for the estimation of global solar radiation using all data for all 14 stations pooled together to predict global solar radiation using linear and multiple linear regression. This was done to improve the low performance of the Angstrom model used for the annual estimation of global solar radiation. The model parameters 'a' and 'b' of Angstrom model were parameterized in terms of the geographical locations (latitude, longitude and elevation) and the meteorological variables (sunshine hour, precipitation, relative humidity and temperature), respectively. This scheme gave better simulation of the global solar radiation compared wi! th other schemes and the original Angstrom models. In addition, the pr eferential consideration of relative humidity to precipitation as potent contributing factor in the estimation of global solar radiation was also established.

  12. The radiative deceleration of ultrarelativistic jets in active galactic nuclei

    NASA Technical Reports Server (NTRS)

    Melia, Fulvio; Konigl, Arieh

    1989-01-01

    A detailed study of the dynamical interaction between a highly relativistic jet and the thermal radiation field from an AGN accretion disk is reported, and the Comptonized spectrum arising from this interaction is self-consistently determined. A simple model that captures the essential radiative and geometrical features of realistic disk configurations is presented, and the disk radiation field is calculated. The results confirm Phinney's (1987) suggestion that the thermal radiation field produced by accretion in an AGN could be very effective in decelerating ultrarelativistic jets that are accreted by electromagnetic or hydromagnetic forces closer to the central black hole. Terminal Lorentz factors are consistent with the values inferred in superluminal radio sources are readily produced in this model for plausible disk and jet parameters without additional acceleration in the interaction zone. A new interpretation of the hard X-ray component detected in BL Lac spectra is proposed.

  13. The radiative deceleration of ultrarelativistic jets in active galactic nuclei

    SciTech Connect

    Melia, F.; Konigl, A.

    1989-05-01

    A detailed study of the dynamical interaction between a highly relativistic jet and the thermal radiation field from an AGN accretion disk is reported, and the Comptonized spectrum arising from this interaction is self-consistently determined. A simple model that captures the essential radiative and geometrical features of realistic disk configurations is presented, and the disk radiation field is calculated. The results confirm Phinney's (1987) suggestion that the thermal radiation field produced by accretion in an AGN could be very effective in decelerating ultrarelativistic jets that are accreted by electromagnetic or hydromagnetic forces closer to the central black hole. Terminal Lorentz factors are consistent with the values inferred in superluminal radio sources are readily produced in this model for plausible disk and jet parameters without additional acceleration in the interaction zone. A new interpretation of the hard X-ray component detected in BL Lac spectra is proposed. 55 refs.

  14. STFC Cosmic Rays Poster additional notes for teachers Cosmic rays receive mention in school physics as a component of background radiation when tackling the

    E-print Network

    ! As a powerful way of visualising ionising radiation, a simple diffusion cloud chamber cannot be matched. Some://www.pasco.com/prodCatalog/SE/SE-7943_diffusion-cloud-chamber-15-cm-diameter/), and at the top end the German firm PHYWE sells/Campus/Info-Center/Exhibition-Area/The-PHYWE-Diffusion- Cloud-Chamber.htm. #12;June 2012 The detection

  15. Generation of hard quanta in the cross-grooved resonator of a free electron laser

    SciTech Connect

    Baryshnikov, F F; Perebeinos, V V; Cheburkin, N V [State Unitary Enterprise, V.K. Orlov Granat Design Bureau, Moscow (Russian Federation)

    2002-06-30

    A new approach to the generation of powerful tunable hard radiation in the cross-grooved resonator (CGR) of a free electron laser is proposed and discussed. Gamma quanta are generated upon backward Compton scattering of intracavity radiation by the electron beam of a free electron laser with a CGR. The use of a CGR considerably increases the power of intracavity radiation, and hence the power of gamma radiation, and also solves the problem of extraction of hard radiation by eliminating the losses in the depth of the cavity mirror, which were inevitable earlier. (lasers)

  16. Synchrotron Radiation

    SciTech Connect

    Wiedemann, Helmut

    2003-08-11

    This book covers the physical aspects of synchrotron radiation generation and is designed as a textbook and reference for graduate students, teachers and scientists utilizing synchrotron radiation. It is my hope that this text may help especially students and young researchers entering this exciting field to gain insight into the characteristics of synchrotron radiation. Discovered in 1945, synchrotron radiation has become the source of photons from the infrared to hard x-rays for a large community of researchers in basic and applied sciences. This process was particularly supported by the development of electron accelerators for basic research in high energy physics. Specifically, the development of the store ring and associated technologies resulted in the availability of high brightness photon beams far exceeding other sources. In this text, the physics of synchrotron radiation for a variety of magnets is derived from first principles resulting in useful formulas for the practitioner. Since the characteristics and quality of synchrotron radiation are intimately connected with the accelerator and electron beam producing this radiation, a short overview of relevant accelerator physics is included.

  17. Hard gamma ray emission from blazars

    NASA Technical Reports Server (NTRS)

    Marscher, Alan P.; Bloom, Steven D.

    1992-01-01

    The gamma-ray emission expected from compact extragalactic sources of nonthermal radiation is examined. The highly variable objects in this class should produce copious amounts of self-Compton gamma-rays in the compact relativistic jet. This is shown to be a likely interpretation of the hard gamma-ray emission recently detected from the quasar 3C 279 during a period of strong nonthermal flaring at lower frequencies. Ways of discriminating between the self-Compton model and other possible gamma-ray emission mechanisms are discussed.

  18. Hardness of Preorder Checking for Basic Formalisms

    NASA Astrophysics Data System (ADS)

    Bozzelli, Laura; Legay, Axel; Pinchinat, Sophie

    We investigate the complexity of preorder checking when the specification is a flat finite-state system whereas the implementation is either a non-flat finite-state system or a standard timed automaton. In both cases, we show that simulation checking is Exptime-hard, and for the case of a non-flat implementation, the result holds even if there is no synchronization between the parallel components and their alphabets of actions are pairwise disjoint. Moreover, we show that the considered problems become Pspace-complete when the specification is assumed to be deterministic. Additionally, we establish that comparing a synchronous non-flat system with no hiding and a flat system is Pspace-hard for any relation between trace containment and bisimulation equivalence.

  19. Hard exclusive electroproduction of ?+?- pairs

    NASA Astrophysics Data System (ADS)

    Airapetian, A.; Akopov, N.; Akopov, Z.; Amarian, M.; Ammosov, V. V.; Andrus, A.; Aschenauer, E. C.; Augustyniak, W.; Avakian, R.; Avetissian, A.; Avetissian, E.; Bailey, P.; Balin, D.; Baturin, V.; Beckmann, M.; Belostotski, S.; Bernreuther, S.; Bianchi, N.; Blok, H. P.; Böttcher, H.; Borissov, A.; Borysenko, A.; Bouwhuis, M.; Brack, J.; Brüll, A.; Bryzgalov, V.; Capitani, G. P.; Chen, T.; Ciullo, G.; Contalbrigo, M.; Dalpiaz, P. F.; de Leo, R.; Demey, M.; de Nardo, L.; de Sanctis, E.; Devitsin, E.; di Nezza, P.; Düren, M.; Ehrenfried, M.; Elalaoui-Moulay, A.; Elbakian, G.; Ellinghaus, F.; Elschenbroich, U.; Fabbri, R.; Fantoni, A.; Fechtchenko, A.; Felawka, L.; Frullani, S.; Gapienko, G.; Gapienko, V.; Garibaldi, F.; Garrow, K.; Garutti, E.; Gavrilov, G.; Gharibyan, V.; Graw, G.; Grebeniouk, O.; Greeniaus, L. G.; Gregor, I. M.; Griffioen, K. A.; Hafidi, K.; Hartig, M.; Hasch, D.; Heesbeen, D.; Henoch, M.; Hertenberger, R.; Hesselink, W. H. A.; Hillenbrand, A.; Hoek, M.; Holler, Y.; Hommez, B.; Iarygin, G.; Ivanilov, A.; Izotov, A.; Jackson, H. E.; Jgoun, A.; Kaiser, R.; Kinney, E.; Kisselev, A.; Kopytin, M.; Korotkov, V.; Kozlov, V.; Krauss, B.; Krivokhijine, V. G.; Lagamba, L.; Lapikás, L.; Laziev, A.; Lenisa, P.; Liebing, P.; Linden-Levy, L. A.; Lipka, K.; Lorenzon, W.; Lu, H.; Lu, J.; Lu, S.; Ma, B.-Q.; Maiheu, B.; Makins, N. C. R.; Mao, Y.; Marianski, B.; Marukyan, H.; Masoli, F.; Mexner, V.; Meyners, N.; Mikloukho, O.; Miller, C. A.; Miyachi, Y.; Muccifora, V.; Nagaitsev, A.; Nappi, E.; Naryshkin, Y.; Nass, A.; Negodaev, M.; Nowak, W.-D.; Oganessyan, K.; Ohsuga, H.; Osborne, A.; Pickert, N.; Potashov, S.; Potterveld, D. H.; Raithel, M.; Reggiani, D.; Reimer, P. E.; Reischl, A.; Reolon, A. R.; Riedl, C.; Rith, K.; Rosner, G.; Rostomyan, A.; Rubacek, L.; Rubin, J.; Ryckbosch, D.; Salomatin, Y.; Sanjiev, I.; Savin, I.; Schäfer, A.; Schill, C.; Schnell, G.; Schüler, K. P.; Seele, J.; Seidl, R.; Seitz, B.; Shanidze, R.; Shearer, C.; Shibata, T.-A.; Shutov, V.; Sinram, K.; Sommer, W.; Stancari, M.; Statera, M.; Steffens, E.; Steijger, J. J. M.; Stenzel, H.; Stewart, J.; Stinzing, F.; Tait, P.; Tanaka, H.; Taroian, S.; Tchuiko, B.; Terkulov, A.; Tkabladze, A.; Trzcinski, A.; Tytgat, M.; Vandenbroucke, A.; van der Nat, P.; van der Steenhoven, G.; van Haarlem, Y.; Vetterli, M. C.; Vikhrov, V.; Vincter, M. G.; Vogel, C.; Vogt, M.; Volmer, J.; Weiskopf, C.; Wendland, J.; Wilbert, J.; Ybeles Smit, G.; Ye, Y.; Ye, Z.; Yen, S.; Zihlmann, B.; Zupranski, P.; Hermes Collaboration

    2004-10-01

    Hard exclusive electroproduction of ?+?- pairs off hydrogen and deuterium targets has been studied by the HERMES experiment at DESY. Legendre moments and of the angular distributions of ?+ mesons in the center-of-mass frame of the pair have been measured for the first time. Their dependence on the ?+?- invariant mass can be understood as being due to the interference between relative P-wave (isovector) and S-, D-wave (isoscalar) states of the two pions. The increase in magnitude of as Bjorken x increases is interpreted in the framework of generalized parton distributions as an enhancement of flavour non-singlet qqbar exchange for larger values of x, which leads to a sizable admixture of isoscalar and isovector pion pairs. In addition, the interference between P-wave and D-wave states separately for transverse and longitudinal pion pairs has been studied. The data indicate that in the f2 (1270) region at = 3 GeV2 higher-twist effects can be as large as the leading-twist longitudinal component.

  20. Hard X-ray and gamma-rays from supernovae

    NASA Technical Reports Server (NTRS)

    Woosley, S. E.

    1993-01-01

    The hard electromagnetic radiation produced by and accompanying the explosion of supernovae is discussed. This radiation may have three origins: (i) the eruption of the shock wave from the surface of the star; (ii) radioactive decay of unstable isotopes produced during the explosion; and (iii) gamma-rays produced by neutrino annihilation following accretion-induced collapse. Though the latter has been proposed as a mechanism for making cosmological gamma-ray bursts, it is shown that this is unlikely.

  1. Hard (State) Problems

    E-print Network

    John A. Tomsick

    2008-12-16

    For microquasars, the one time when these systems exhibit steady and powerful jets is when they are in the hard state. Thus, our understanding of this state is key to learning about the disk/jet connection. Recent observational and theoretical results have led to questions about whether we really understand the physical properties of this state, and even our basic picture of this state is uncertain. Here, I discuss some of the recent developments and possible problems with our understanding of this state. Overall, it appears that the strongest challenge to the standard truncated disk picture is the detection of broad iron features in the X-ray spectra, and it seems that either there is a problem with the truncated disk picture or there is a problem with the relativistic reflection models used to explain the broad iron features.

  2. Exciting Hard Spheres

    E-print Network

    T. Antal; P. L. Krapivsky; S. Redner

    2008-05-25

    We investigate the collision cascade that is generated by a single moving incident particle on a static hard-sphere gas. We argue that the number of moving particles at time t grows as t^{xi} and the number collisions up to time t grows as t^{eta}, with xi=2d/(d+2) and eta=2(d+1)/(d+2) and d the spatial dimension. These growth laws are the same as those from a hydrodynamic theory for the shock wave emanating from an explosion. Our predictions are verified by molecular dynamics simulations in d=1 and 2. For a particle incident on a static gas in a half-space, the resulting backsplatter ultimately contains almost all the initial energy.

  3. Experiment with the SPR-N Instrument Onboard the CORONAS-F Satellite: Polarization, Temporal, and Spectral Characteristics of the Hard X-Ray of the Solar Flares

    NASA Astrophysics Data System (ADS)

    Zhitnik, I. A.; Logachev, Yu. I.; Bogomolov, A. V.; Bogomolov, V. V.; Denisov, Yu. I.; Kavanosyan, S. S.; Kuznetsov, S. N.; Morozov, O. V.; Myagkova, I. N.; Svertilov, S. I.; Ignatiev, A. P.; Oparin, S. N.; Pertsov, A. A.

    During the experiment with a polarimeter SPR-N onboard the CORONAS-F satellite, polarization of the X-ray of solar flares within the energy ranges of 20-40, 40-60, and 60-100 keV was measured according to Thomson scattering of X-ray photons in Beryllium plates with the following registration of the scattered photons by means of a system of six scintillation detectors based on Cs I(Na). As a result of observations for the period from August 2001 till December 2005, hard X-ray radiation was registered for 128 solar flares. During the event of 29 October 2003 degree of polarization of the radiation within the channels 40-60 and 60-100 keV exceeded 70 %, and within the channel 20-40 keV—50 %. Time profiles of the part of polarized radiation, orientation of the maximum polarization on the solar disc were obtained. The upper limit of the polarized radiation part for 25 events was estimated at the level of 8-40 %. For all registered flares time profiles (with resolution of up to 4 s) were registered, hard X-ray fluxes were determined, and spectrum factor was estimated. For the most powerful events which were observed during October-November 2003 and on January 20, 2005, the data on the dynamics of the characteristics of thermal and non-thermal components of X-radiation were obtained.

  4. THE HARD X-RAY SPECTRUM OF NGC 1365: SCATTERED LIGHT, NOT BLACK HOLE SPIN

    SciTech Connect

    Miller, L. [Department of Physics, Oxford University, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom); Turner, T. J. [Department of Physics, University of Maryland Baltimore County, Baltimore, MD 21250 (United States)

    2013-08-10

    Active galactic nuclei (AGNs) show excess X-ray emission above 10 keV compared with extrapolation of spectra from lower energies. Risaliti et al. have recently attempted to model the hard X-ray excess in the type 1.8 AGN NGC 1365, concluding that the hard excess most likely arises from Compton-scattered reflection of X-rays from an inner accretion disk close to the black hole. Their analysis disfavored a model in which the hard excess arises from a high column density of circumnuclear gas partially covering a primary X-ray source, despite such components being required in the NGC 1365 data below 10 keV. Using a Monte Carlo radiative transfer approach, we demonstrate that this conclusion is invalidated by (1) use of slab absorption models, which have unrealistic transmission spectra for partial covering gas, (2) neglect of the effect of Compton scattering on transmitted spectra, and (3) inadequate modeling of the spectrum of scattered X-rays. The scattered spectrum is geometry-dependent and, for high global covering factors, may dominate above 10 keV. We further show that, in models of circumnuclear gas, the suppression of the observed hard X-ray flux by reprocessing may be no larger than required by the ''light bending'' model invoked for inner disk reflection, and the expected emission line strengths lie within the observed range. We conclude that the time-invariant ''red wing'' in AGN X-ray spectra is probably caused by continuum transmitted through and scattered from circumnuclear gas, not by highly redshifted line emission, and that measurement of black hole spin is not possible.

  5. COMPONENTS OF LASER SYSTEMS AND PROCESSES OCCURRING IN THEM: Fast-response system for stabilization of the axis of the angular distribution of laser radiation

    NASA Astrophysics Data System (ADS)

    Vinogradov, E. G.; Glebova, S. N.; Pavlov, N. V.; Razhenkov, E. T.

    1988-09-01

    A fast-acting system for stabilization of the axis of the angular distribution of radiation from a continuous-flow CO2 laser is considered. The results of a simulation experiment are reported: they show that it is possible to suppress, by 24-28 dB, fluctuations of the position of the axis in the spectral range 0-20 Hz. This makes the proposed system a promising method for large-aperture laser beams.

  6. Advanced radiator concepts

    NASA Technical Reports Server (NTRS)

    Diem-Kirsop, P. S.

    1985-01-01

    The liquid droplet radiator and the liquid belt radiator currently under study by the NASA LeRC are discussed. These advanced concepts offer benefits in reduced mass, compact stowage, and ease of deployment. Operation and components of the radiators are described, heat transfer characteristics are discussed, and critical technologies are identified. The impact of the radiators on large power systems is also assessed.

  7. A component of gamma-radiation-induced cell death in E. coli is programmed and interlinked with activation of caspase-3 and SOS response.

    PubMed

    Wadhawan, Surbhi; Gautam, Satyendra; Sharma, Arun

    2013-08-01

    The current study deals with the molecular mechanism of radiation-induced cell death (RICD) in Escherichia coli. Irradiated E. coli cells displayed markers similar to those found in eukaryotic programmed cell death (PCD) such as caspase-3 activation and phosphatidylserine externalization. RICD was found to be suppressed upon pretreatment with sublethal concentrations of rifampicin or chloramphenicol, indicating the requirement of de novo gene expression. RICD was also found to be inhibited by cell permeable inhibitors of caspase-3 or poly (ADP-ribose) polymerase, indicating the involvement of PCD during RICD in E. coli. Radiation-induced SOS response was alleviated as observed with decrease in LexA level and also reduced cell filamentation frequency in the presence of caspase inhibitor. Further, the inhibitor-mediated rescue was not observed in single-gene knockouts of umuC, umuD, recB and ruvA, the genes which are associated with SOS response. This implies a linkage between SOS response and PCD in radiation-exposed E. coli cells. PMID:23807199

  8. Hardness Assurance Techniques for New Generation COTS Devices

    NASA Technical Reports Server (NTRS)

    Lee, C. I.; Rax, B. G.; Johnston, A. H.

    1996-01-01

    Hardness Assurance (HA) techniques and total dose radiation characterization data for new generation linear and COTS devices from various manufacturers are presented. A bipolar op amp showed significant degradation at HDR, not at low dose rate environment. New generation low-power op amps showed more degradation at low voltage applications. HA test techniques for COTS devices are presented in this paper.

  9. Imaging hard X-ray telescope developments in United States and Europe

    NASA Astrophysics Data System (ADS)

    Zhou, Yi

    The hard X-ray (20 keV up to 1 MeV) energy band is a good window for us to learn the high energy radiation processes in astrophysics. The imaging hard X-ray telescopes provide better resolution and sensitivity for studying hard X-ray astrophysics. In this paper, the recent years developments of imaging hard X-ray telescopes in United States and Europe are introduced, including 1) EXITE2 - a phoswich imaging hard X-ray telescope designed and operated by Harvard-Smithsonian Center for Astrophysics (CfA); 2) EXIST - an imaging hard X-ray all-sky survey, which will be carried by ULDB (EXIST-LITE) or mounted on international space station (EXIST-ISS) in the year of 2010 and 3) HERO - a newly developed hard X-ray optics instrument, built by NASA/MSFC.

  10. K.K. Gan B Layer Workshop 1 Rad-Hard Opto-Link Upgrade

    E-print Network

    Gan, K. K.

    increase in # pixel modules 2 Gb/s #12;K.K. Gan B Layer Workshop 15 PIN Responsivity Si PIN responsivity-pair cables Bandwidth of fusion spliced SIMM-GRIN fibers Radiation hardness/speed of PIN/VCSEL arrays #12;K and opto module simplify both design/production 8 m of rad-hard/low-bandwidth SIMM fiber fusion spliced

  11. Radio imaging observations of hard x-ray microflares observed by RHESSI

    NASA Astrophysics Data System (ADS)

    Kundu, M.; Trottet, G.; Garaimov, V.; Grigis, P.

    We describe the properties of two sets of microflares observed simultaneously by RHESSI (Ramaty High Energy Solar Spectroscopic Imager) in hard X-rays and by two radio imaging instruments--NoRH (Nobeyama Radio Heliograph) in microwaves (17 GHz) and NRH (Nancay Radio Heliograph) at metric wavelengths. The two sets of events occurred in two different time zones, and as a result we do not have simultaneous imaging data in microwaves and metric wavlengths for the same RHESSI events. We'll discuss four events--two observed by NoRH in microwaves and two observed by NRH in meter waves, along with RHESSI events. The microwave (17 GHz) events occurred in AR 9934 at 03:58 UT May 3, 2002 and at 05:08 UT May 4, 2002. We have detected microwave (17 & 34 GHz) emissions in association with RHESSI microflares in the energy range 3-50 keV. The microwave emission comes from footpoints for higher energies, and from the entire mini or small flaring loop for lower energies. The relative positions of microwaves and hard X-rays are as they should be in normal flares. Sometimes the two sources coincide, at other times the two sources are at opposite ends of the flaring loop. One sees the mini flaring loops clearly in NoRH images. RHESSI maps at the time of maximum X-ray emission during the event of May 3, 2002 clearly show an X-ray loop in the range 3-6 keV and two footpoints of the loop in the 6-12 and 12-25 keV ranges. These footpoints are located above opposite magnetic polarities as seen in overlays of hard X-ray images on the MDI images. The MDI magnetograms taken before the microflares show rapid evolution of the magnetic field, including sometimes the emergence of a new region. The hard X-ray spectrum of microwave associated RHESSI microflares can be fit by a thermal component (EM ˜ 3× 1046 cm-3) at low energies (3-6 keV) and a nonthermal component (with slope -3.2) at higher energies. The two metric events imaged by NRH occurred on August 5 and September 3, 2003, one located on the disk and the other at the limb. The RHESSI microflare sources are compact. They are accompanied by a series of metric type III bursts at 150-410 MHz originating from sources located above the RHESSI HXR source. Their source positions show frequency dispersion as expected from plasma radiation sources. The properties of these microflare sources in hard X-rays, microwave and meter wavelengths will be discussed.

  12. LIFE Materials: Topical Assessment Report for LIFE Volume 1 TOPIC: Solid First Wall and Structural Components TASK: Radiation Effects on First Wall

    SciTech Connect

    Caro, A

    2008-11-26

    This report consists of the following chapters: CHAPTER A: LIFE Requirements for Materials. Part 1: The structure of the First Wall--Basic requirements; A qualitative view of the challenge; The candidate materials; and Base-line material's properties. CHAPTER B: Summary of Existing Knowledge--Brief historical introduction; Design window; The temperature window; Evolution of the design window with damage; Damage calculations; He and H production; Swelling resistance; Incubation dose for swelling; Design criterion No. 1, Strength; Design criterion No. 2, Corrosion resistance; Design criterion No. 3, Creep resistance; Design criterion No. 4, Radiation induced embrittlement; and Conclusions. CHAPTER C: Identification of Gaps in Knowledge & Vulnerabilities. CHAPTER D: Strategy and Future Work.

  13. COMPONENTS OF LASER SYSTEMS AND STABILITY PROBLEMS: Parametric generation of tunable picosecond light pulses as a result of pumping with radiation from a stimulated Raman scattering compressor

    NASA Astrophysics Data System (ADS)

    Buzyalis, R. R.; Dementjev, Aleksandr S.; Deringas, A. L.; Kabelka, V. I.; Kosenko, E. K.; Milyauskas, A. A.

    1988-08-01

    Typical parametric oscillations were observed in a laser with a stimulated Raman scattering compressor. This laser generated pulses of ~ 15 ps duration at a wavelength of 0.63 ?m and the width of the spectrum was ~ 0.7 cm- 1. The parametric radiation was tunable within the range 1-1.5 ?m. A study was made of the statistical properties of the generation process. The energy stability of the pulses generated in such an optical parametric oscillator was twice as high as in the case when pumping was provided by a picosecond YAG:Nd laser with passive mode locking.

  14. Nanopatterned ferroelectrics for ultrahigh density rad-hard nonvolatile memories.

    SciTech Connect

    Brennecka, Geoffrey L.; Stevens, Jeffrey; Scrymgeour, David; Gin, Aaron V.; Tuttle, Bruce Andrew

    2010-09-01

    Radiation hard nonvolatile random access memory (NVRAM) is a crucial component for DOE and DOD surveillance and defense applications. NVRAMs based upon ferroelectric materials (also known as FERAMs) are proven to work in radiation-rich environments and inherently require less power than many other NVRAM technologies. However, fabrication and integration challenges have led to state-of-the-art FERAMs still being fabricated using a 130nm process while competing phase-change memory (PRAM) has been demonstrated with a 20nm process. Use of block copolymer lithography is a promising approach to patterning at the sub-32nm scale, but is currently limited to self-assembly directly on Si or SiO{sub 2} layers. Successful integration of ferroelectrics with discrete and addressable features of {approx}15-20nm would represent a 100-fold improvement in areal memory density and would enable more highly integrated electronic devices required for systems advances. Towards this end, we have developed a technique that allows us to carry out block copolymer self-assembly directly on a huge variety of different materials and have investigated the fabrication, integration, and characterization of electroceramic materials - primarily focused on solution-derived ferroelectrics - with discrete features of {approx}20nm and below. Significant challenges remain before such techniques will be capable of fabricating fully integrated NVRAM devices, but the tools developed for this effort are already finding broader use. This report introduces the nanopatterned NVRAM device concept as a mechanism for motivating the subsequent studies, but the bulk of the document will focus on the platform and technology development.

  15. Residual stress control and design of next-generation ultra-hard gear steels

    NASA Astrophysics Data System (ADS)

    Qian, Yana

    In high power density transmission systems, Ni-Co secondary hardening steels have shown great potential for next-generation gear applications due to their excellent strength, toughness and superior fatigue performance. Study of residual stress generation and evolution in Ferrium C61 and C67 gear steels revealed that shot peening and laser peening processes effectively produce desired beneficial residual stress in the steels for enhanced fatigue performance. Surface residual stress levels of -1.4GPa and -1.5GPa were achieved in shot peened C61 and laser peened C67, respectively, without introducing large surface roughness or defects. Higher compressive residual stress is expected in C67 according to a demonstrated correlation between attainable residual stress and material hardness. Due to the lack of appropriate shot media, dual laser peening is proposed for future peening optimization in C67. A novel non-destructive synchrotron radiation technique was implemented and applied for the first time for residual stress distribution analysis in gear steels with large composition and property gradients. Observed substantial residual stress redistribution and material microstructure change during the rolling contact fatigue screening test with extremely high 5.4GPa load indicates the unsuitability of the test as a fatigue life predictor. To exploit benefits of higher case hardness and associated residual stress, a new material and process (CryoForm70) aiming at 70Rc surface hardness was designed utilizing the systems approach based on thermodynamics and secondary hardening mechanisms. The composition design was first validated by the excellent agreement between experimental and theoretical core martensite start temperature in the prototype. A novel cryogenic deformation process was concurrently designed to increase the case martensite volume fraction from 76% to 92% for enhanced strengthening efficiency and surface hardness. High temperature vacuum carburizing was optimized for desired carbon content profiles using carbon diffusion simulation in the multi-component system. After cyclic tempering with intermediate cryogenic treatment, a case hardness of 68.5 +/- 0.3Rc at 0.72 +/- 0.2wt% carbon content was achieved. The design demonstrated the effectiveness of cryogenic deformation in promoting martensite transformation for high carbon and high alloy steels. Good agreement between achieved and predicted case and core hardness supports the effectiveness of the computational design approach.

  16. Measuring the Hardness of Minerals

    ERIC Educational Resources Information Center

    Bushby, Jessica

    2005-01-01

    The author discusses Moh's hardness scale, a comparative scale for minerals, whereby the softest mineral (talc) is placed at 1 and the hardest mineral (diamond) is placed at 10, with all other minerals ordered in between, according to their hardness. Development history of the scale is outlined, as well as a description of how the scale is used…

  17. Hardness Amplification Proofs Require Majority Ronen Shaltiel

    E-print Network

    Viola, Emanuele

    Hardness Amplification Proofs Require Majority Ronen Shaltiel Emanuele Viola April 28, 2010 Abstract Hardness amplification is the fundamental task of converting a -hard function f : {0, 1}n {0, 1} into a (1/2 - )-hard function Amp(f), where f is -hard if small circuits fail to compute f on at least

  18. Murine natural resistance to Trypanosoma lewisi involves complement component C3 and radiation-resistant, silica dust-sensitive effector cells

    SciTech Connect

    Albright, J.W.; Albright, J.F.

    1985-01-01

    The phenomenon of natural (innate) resistance is exemplified by the solid resistance of mice to infection with the rat-specific Trypanosoma lewisi. We provide more information about the mechanism of resistance in this model system. Resistance was not diminished in aged mice or reduced by ionizing radiation or splenectomy. There was no difference in resistance of C5-deficient mice (B10.D2/oSn and AKR) compared with their normocomplementemic counterparts (B10.D2/nSn and C57BL/6). Treatment of mice with cobra venom factor resulted in greatly prolonged survival of T. lewisi in mice. Combined treatment of mice with cobra venom factor and silica dust resulted in not only prolonged survival but also considerable intravascular growth of the parasite and resultant death of the mice. T. lewisi cells from irradiated donor rats, or after surface coat removal with trypsin, were eliminated by inoculated mice more efficiently than were parasites acquired from normal rats. Incubation of trypanosomes obtained from irradiated rats in normal rat serum restored their resistance to rapid elimination. From the results of these studies and other recent investigations, we have concluded that murine resistance to T. lewisi involves activation and binding of C3b by uncoated trypanosomes and concomitant participation of radiation-resistant, silica dust-sensitive effector cells (probably macrophages and neutrophils), and rat plasma proteins, integrated into the trypanosome surface coat, stabilize the coat, make it less susceptible to removal when the trypanosome is present in the mouse bloodstream, and thus delay exposure of underlying molecules (receptors) that activate murine C3.

  19. Hard sphere correlation functions in the Percus-Yevick approximation

    Microsoft Academic Search

    J. W. Perram

    1975-01-01

    A reformulation of the Ornstein-Zernike equation permits rapid and simple numerical calculation of the total correlation functions for single and multi-component systems of hard spheres. Such correlation functions permit the application of sophisticated statistical mechanical perturbation theories to more complicated systems than has been possible heretofore.

  20. Investigations on hard machining of Impax Hi Hard tool steel

    Microsoft Academic Search

    Bala Murugan Gopalsamy; Biswanath Mondal; Sukamal Ghosh; Kristian Arntz; Fritz Klocke

    2009-01-01

    In this paper, experimental investigations are carried out by end milling process on hardened tool steel, Impax Hi Hard (Hardness\\u000a 55 HRC) a newly developed tool steel material used by tool and die making industries. Experiments are performed with an aim\\u000a to study performance investigations of machining parameters such as cutting speed, feed, depth of cut and width of cut

  1. Nonconventional hard-metal compositions

    SciTech Connect

    Sheinberg, H.

    1982-01-01

    A novel hard-metal composition comprising borides and carbides of tungsten, nickel, and iron is made by reaction hot-pressing mixtures of elemental tungsten, nickel, and iron powders with small quantities of boron carbide. The hardness of these compositions is in the range of the hardest conventional tungsten carbide-cobalt compositions. It was subsequently determined that molybdenum can be substituted in part or totally for the tungsten in the composition with a minimum reduction in hardness. This new composition can be used in high-pressure anvils; it sustains higher pressures than commercial carbides without plastic deformation.

  2. Radiation-Hardened Solid-State Drive

    NASA Technical Reports Server (NTRS)

    Sheldon, Douglas J.

    2010-01-01

    A method is provided for a radiationhardened (rad-hard) solid-state drive for space mission memory applications by combining rad-hard and commercial off-the-shelf (COTS) non-volatile memories (NVMs) into a hybrid architecture. The architecture is controlled by a rad-hard ASIC (application specific integrated circuit) or a FPGA (field programmable gate array). Specific error handling and data management protocols are developed for use in a rad-hard environment. The rad-hard memories are smaller in overall memory density, but are used to control and manage radiation-induced errors in the main, and much larger density, non-rad-hard COTS memory devices. Small amounts of rad-hard memory are used as error buffers and temporary caches for radiation-induced errors in the large COTS memories. The rad-hard ASIC/FPGA implements a variety of error-handling protocols to manage these radiation-induced errors. The large COTS memory is triplicated for protection, and CRC-based counters are calculated for sub-areas in each COTS NVM array. These counters are stored in the rad-hard non-volatile memory. Through monitoring, rewriting, regeneration, triplication, and long-term storage, radiation-induced errors in the large NV memory are managed. The rad-hard ASIC/FPGA also interfaces with the external computer buses.

  3. Brain components

    MedlinePLUS Videos and Cool Tools

    The brain is composed of more than a thousand billion neurons. Specific groups of them, working in concert, provide ... of information. The 3 major components of the brain are the cerebrum, cerebellum, and brain stem. The ...

  4. Blood Components

    MedlinePLUS

    ... of volume) suspended in plasma (~55% of volume). Red cells Red cells, or erythrocytes , carry oxygen from the lungs ... frozen plasma. Transfusable Blood Components Summary Whole Blood Red Blood Cells Platelets Plasma Cryoprecipitated AHF COLOR OF ...

  5. HARD CLAM HYBRIDS FOR FLORIDAAQUACULTURE: HATCHERY CULTURE

    E-print Network

    Florida, University of

    HARD CLAM HYBRIDS FOR FLORIDAAQUACULTURE: HATCHERY CULTURE John Scarpa: Harbor Branch Oceanographic and Aquatic Sciences, Gainesville, FL 32653 Introduction The hard clam (Mercenaria mercenaria notata summers of Florida. Southern hard clams, Mercenaria campechiensis, may have production traits

  6. COMPONENTS OF LASER SYSTEMS AND PROCESSES OCCURRING IN THEM: Utilization of competition between counterpropagating waves for modulation and stabilization of the radiation emitted from a ring laser

    NASA Astrophysics Data System (ADS)

    Kornienko, L. S.; Nani?, O. E.; Shelaev, A. N.

    1988-09-01

    Theoretical and experimental investigations were made of the possibility of increasing the efficiency of intracavity modulation and stabilization of the radiation emitted from ring lasers by utilization of the competition between counterpropagating waves. It was established that in the case of solid-state ring lasers one can switch rapidly the direction of counterpropagating waves both in the case of forced mode locking and in the case of single-mode emission without spike transient processes at a relaxation frequency typical of solid-state lasers. An analysis was made of the conditions for significant reduction of the switching time and a method is suggested for achieving this by simultaneous modulation of the amplitude nonreciprocity and of the coupling between counterpropagating waves. It is shown that highly stable unidirectional single-mode operation of a solid-state ring laser can be achieved as a result of weak modulation of the resonator perimeter. Various time dependences of the intensities of counterpropagating waves and stabilization of bidirectional operation of a solid-state ring laser were achieved using a magnetooptic feedback loop.

  7. Effects of Genotype and Environment on the Antioxidant Properties of Hard Winter Wheat Bran

    E-print Network

    Liu, Jian-Guo

    Effects of Genotype and Environment on the Antioxidant Properties of Hard Winter Wheat Bran JEFFREY promoted research on the bioactive components of agricultural products. Wheat is an important agricultural (E) to hard winter wheat bran antioxidant properties, as well as correlations of these properties

  8. Response of nickel surface to pulsed fusion plasma radiations

    SciTech Connect

    Niranjan, Ram, E-mail: niranjan@barc.gov.in; Rout, R. K., E-mail: niranjan@barc.gov.in; Srivastava, R., E-mail: niranjan@barc.gov.in; Gupta, Satish C. [Applied Physics Division, Bhabha Atomic Research Centre, Mumbai-400085 (India); Chakravarthy, Y. [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Mumbai-400085 (India); Patel, N. N. [High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Mumbai-400085 (India); Alex, P. [Materials Processing Division, Bhabha Atomic Research Centre, Mumbai-400085 (India)

    2014-04-24

    Nickel based alloys are being projected as suitable materials for some components of the next generation fusion reactor because of compatible thermal, electrical and mechanical properties. Pure nickel material is tested here for possibility of similar application purpose. Nickel samples (> 99.5 % purity) are exposed here to plasma radiations produced due to D-D fusion reaction inside an 11.5 kJ plasma focus device. The changes in the physical properties of the nickel surface at microscopic level which in turn change the mechanical properties are analyzed using scanning electron microscope, optical microscope, glancing incident X-ray diffractometer and Vicker's hardness gauge. The results are reported here.

  9. 30 CFR 77.1710-1 - Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 false Distinctively colored hard hats or hard caps; identification for newly...1710-1 Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively...

  10. 30 CFR 75.1720-1 - Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 false Distinctively colored hard hats, or hard caps; identification for newly...1720-1 Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively...

  11. 30 CFR 77.1710-1 - Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 false Distinctively colored hard hats or hard caps; identification for newly...1710-1 Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively...

  12. 30 CFR 77.1710-1 - Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 false Distinctively colored hard hats or hard caps; identification for newly...1710-1 Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively...

  13. 30 CFR 77.1710-1 - Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 false Distinctively colored hard hats or hard caps; identification for newly...1710-1 Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively...

  14. 30 CFR 75.1720-1 - Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 false Distinctively colored hard hats, or hard caps; identification for newly...1720-1 Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively...

  15. 30 CFR 75.1720-1 - Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 false Distinctively colored hard hats, or hard caps; identification for newly...1720-1 Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively...

  16. 30 CFR 77.1710-1 - Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 false Distinctively colored hard hats or hard caps; identification for newly...1710-1 Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively...

  17. 30 CFR 75.1720-1 - Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 false Distinctively colored hard hats, or hard caps; identification for newly...1720-1 Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively...

  18. 30 CFR 75.1720-1 - Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 false Distinctively colored hard hats, or hard caps; identification for newly...1720-1 Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively...

  19. Estimates of HZE particle contributions to SPE radiation exposures on interplanetary missions

    NASA Technical Reports Server (NTRS)

    Townsend, L. W.; Cucinotta, F. A.; Wilson, J. W.; Bagga, R.

    1994-01-01

    Estimates of radiation doses resulting from possible HZE (high energy heavy ion) components of Solar Particle Events (SPEs) are presented for crews of manned interplanetary missions. The calculations assume a model spectrum obtained by folding measured solar flare HZE particle abundances with the measured energy spectra of SPE alpha particles. These hypothetical spectra are then transported through aluminum spacecraft shielding. The results, presented as estimates of absorbed dose and dose equivalent, indicate that HZE components by themselves are not a major concern for crew protection but should be included in any overall risk assessment. The predictions are found to be sensitive to the assumed spectral hardness parameters.

  20. Explanation and the Hard Problem

    Microsoft Academic Search

    Wayne Wright

    2007-01-01

    This paper argues that the form of explanation at issue in the hard problem of consciousness is scientifically irrelevant,\\u000a despite appearances to the contrary. In particular, it is argued that the ‘sense of understanding’ that plays a critical role\\u000a in the form of explanation implicated in the hard problem provides neither a necessary nor a sufficient condition on satisfactory\\u000a scientific

  1. Easy Problems are Sometimes Hard

    Microsoft Academic Search

    Ian P. Gent; Toby Walsh

    1994-01-01

    We present a detailed experimental investigation of the easy-hard-easyphase transition for randomly generated instances of satisfiability problems.Problems in the hard part of the phase transition have been extensively usedfor benchmarking satisfiability algorithms. This study demonstrates thatproblem classes and regions of the phase transition previously thought tobe easy can sometimes be orders of magnitude more difficult than the worstproblems in problem

  2. Sintered titanium carbide hard alloys

    Microsoft Academic Search

    G. V. Samsonov; N. N. Sergeev; G. T. Dzodziev; V. K. Vitryanyuk; L. V. Latyaeva

    1971-01-01

    1.A study was made of the preparation of titanium carbide hard alloys with a nickel binder. It is shown that satisfactory mechanical properties (bend strength 107–115 kg\\/mm2, hardness 90–90.5 HRA) are exhibited by 80% TiC-20% Ni alloys produced from fine-milled mixtures by sintering in a vacuum of 5·10-3 mm Hg at a temperature of 1300‡C and an isothermal holding time

  3. QPX Disease in Hard Clams

    NSDL National Science Digital Library

    Debra Barnes

    This New York SeaGrant PDF-brochure examines QPX (Quahog Parasite Unknown, a disease-causing parasite) as it relates to the hard clam fishery in New York. It discusses the origin of QPX, how it infects hard clams, where it has been found, signs of QPX disease, why people in New York should be concerned, and what is being done to control its spread.

  4. XMM-Newton Detection of Hard X-ray Emission in the Nitrogen-Type Wolf-Rayet Star WR110

    E-print Network

    S. L. Skinner; S. A. Zhekov; M. Guedel; W. Schmutz

    2002-03-18

    We have used the excellent sensitivity of XMM-Newton to obtain the first high-quality X-ray spectrum of a Wolf-Rayet (WR) star which is not known to be a member of a binary system. Our target, the nitrogen-type star WR 110 (= HD 165688) was also observed and detected with the VLA at four different frequencies. The radio data are in excellent agreement with that expected for free-free wind emission. and the ionized mass-loss rate is derived. The X-ray emission measure distribution shows a dominant contribution from cool plasma at kT$_{cool}$ = 0.5 keV (6 MK) which is only weakly absorbed. We argue that this cool emission originates at hundreds of radii if the wind is spherical and homogeneous and derive shock velocities and the X-ray filling factor using radiative shock models. A surprising result is the unambiguous detection of a hard X-ray component clearly seen in the hard-band images and the spectra. This hard component accounts for about half of the observed flux and can be acceptably fitted by a hot optically thin thermal plasma or a power-law model. If the emission is thermal, then a temperature kT$_{hot}$ $\\geq$ 3 keV is derived. Such high temperatures are not predicted by current instability-driven wind shock models. We examine several alternatives and show that the hard emission could be accounted for by the WR wind shocking onto a close stellar companion which has so far escaped detection. However, until persuasive evidence for binarity is found we are left with the intriguing possibility that the hard X-ray emission is produced entirely by the Wolf-Rayet star.

  5. Components of both major axial patterning systems of the Bilateria are differentially expressed along the primary axis of a 'radiate' animal, the anthozoan cnidarian Acropora millepora.

    PubMed

    de Jong, Danielle M; Hislop, Nikki R; Hayward, David C; Reece-Hoyes, John S; Pontynen, Patricia C; Ball, Eldon E; Miller, David J

    2006-10-15

    Cnidarians are animals with a single (oral/aboral) overt body axis and with origins that nominally predate bilaterality. To better understand the evolution of axial patterning mechanisms, we characterized genes from the coral, Acropora millepora (Class Anthozoa) that are considered to be unambiguous markers of the bilaterian anterior/posterior and dorsal/ventral axes. Homologs of Otx/otd and Emx/ems, definitive anterior markers across the Bilateria, are expressed at opposite ends of the Acropora larva; otxA-Am initially around the blastopore and later preferentially toward the oral end in the ectoderm, and emx-Am predominantly in putative neurons in the aboral half of the planula larva, in a domain overlapping that of cnox-2Am, a Gsh/ind gene. The Acropora homologs of Pax-3/7, NKX2.1/vnd and Msx/msh are expressed in axially restricted and largely non-overlapping patterns in larval ectoderm. In Acropora, components of both the D/V and A/P patterning systems of bilateral animals are therefore expressed in regionally restricted patterns along the single overt body axis of the planula larva, and two 'anterior' markers are expressed at opposite ends of the axis. Thus, although some specific gene functions appear to be conserved between cnidarians and higher animals, no simple relationship exists between axial patterning systems in the two groups. PMID:16952346

  6. Inorganic particulates in pneumoconiotic lungs of hard metal grinders.

    PubMed Central

    Rüttner, J R; Spycher, M A; Stolkin, I

    1987-01-01

    Data from the analysis of lung dust in 16 metal grinders who had been exposed to hard metals between five and 44 years is reported. The mean latent time between the first exposure and analysis in biopsy or necropsy specimens was 33.6 years. Mineralogical and elementary analysis by a variety of techniques showed small or trace amounts of hard metal in all lungs. Many specimens, however, did not contain all hard metal components, cobalt, for example, being detected in four cases only. All the lungs contained quartz and silicates and in most of the necropsy cases carborundum and corundum could also be shown. Histologically no specific pattern was found. The appearances included mixed dust nodular pneumoconiosis, diffuse interstitial lung fibrosis, and foreign body and sarcoid like granulomatous changes. In view of the mixed dust exposure of the hard metal grinders and the variable histological appearance we think that the term "mixed dust pneumoconiosis in hard metal grinders" is more appropriate than "hard metal lung" to describe this condition. PMID:3676118

  7. Hard Hat Use and Inspection Hard hats are an important piece of personal protective equipment (PPE). Hard hats worn

    E-print Network

    Eisen, Michael

    Hard Hat Use and Inspection Hard hats are an important piece of personal protective equipment (PPE). Hard hats worn at Berkeley Lab must comply with the requirements of ANSI Z89.1 for impact protection follow manufacturer's recommendations for specific inspection procedures. Hard Hat Inspection - Bullard

  8. Long-term variability of AGN at hard X-rays

    NASA Astrophysics Data System (ADS)

    Soldi, S.; Beckmann, V.; Baumgartner, W. H.; Ponti, G.; Shrader, C. R.; Lubi?ski, P.; Krimm, H. A.; Mattana, F.; Tueller, J.

    2014-03-01

    Aims: Variability at all observed wavelengths is a distinctive property of active galactic nuclei (AGN). Hard X-rays provide us with a view of the innermost regions of AGN, mostly unbiased by absorption along the line of sight. Characterizing the intrinsic hard X-ray variability of a large AGN sample and comparing it to the results obtained at lower X-ray energies can significantly contribute to our understanding of the mechanisms underlying the high-energy radiation. Methods: Swift/BAT provides us with the unique opportunity to follow, on time scales of days to years and with regular sampling, the 14-195 keV emission of the largest AGN sample available up to date for this kind of investigation. As a continuation of an early work using the first 9 months of BAT data, we study the amplitude of the variations and their dependence on subclass and on energy, for a sample of 110 radio quiet and radio loud AGN selected from the BAT 58-month survey. Results: About 80% of the AGN in the sample are found to exhibit significant variability on month-to-year time scales. In particular, radio loud sources are the most variable, and Seyfert 1.5-2 galaxies are slightly more variable than Seyfert 1, while absorbed and unabsorbed objects show similar timing properties. The amplitude of the variations and their energy dependence are incompatible with variability being driven at hard X-rays by changes in the absorption column density. In general, the variations in the 14-24 and 35-100 keV bands are correlated well, suggesting a common origin to the variability across the BAT energy band. However, radio quiet AGN display on average 10% larger variations at 14-24 keV than at 35-100 keV, and a softer-when-brighter behavior for most of the Seyfert galaxies with detectable spectral variability on a time scale of a month. In addition, sources with harder spectra are found to be more variable than softer ones, unlike what it is observed below 10 keV. These properties are generally consistent with a variable, in flux and shape, power law continuum, pivoting at energies ? 50 keV, to which a constant reflection component is superposed. When the same time scales are considered, the timing properties of AGN at hard X-rays are comparable to those at lower energies, with at least some of the differences possibly ascribable to components contributing differently in the two energy domains (e.g., reflection, absorption). Table 2 is available in electronic form at http://www.aanda.org

  9. On-board data recorder for hard-target weapons

    SciTech Connect

    Niven, W.A.; Jaroska, M.F.

    1981-03-16

    The Naval Weapons Center has several hard target penetration weapons development programs in progress. One of the critical problem areas in these programs is the extreme difficulty of measuring acceleration-time data from penetration tests due to the hostile nature of the environment. The information is of vital importance in order to produce survivability design criteria for components expected to function in such severe environments. The development of a small, rugged, solid state on-board recorder to capture dynamic data for hard target penetration weapon testing is described.

  10. On-board data recorder for hard-target weapons

    SciTech Connect

    Niven, W.A.; Jaroska, M.F.

    1981-03-16

    The Naval Weapons Center is conducting several hard target penetration weapons development programs. One of the critical problem areas in these programs is the extreme difficulty, due to the hostile nature of the environment, of measuring acceleration-time data from penetration tests. The information is of vital importance in determining design criteria for survivability of components expected to function in such severe environments. This report describes the development of a small, rugged, solid-state on-board recorder to capture dynamic data for testing hard target penetration weapons.

  11. JPL Radiation Effects Facilities

    NASA Technical Reports Server (NTRS)

    Thorbourn, Dennis

    2013-01-01

    Radiation Effects Group investigates the effects of space radiation on present and future microelectronic and optoelectronic technologies, evaluate the risk of using them in specific space missions, and recommend component and design techniques for JPL and NASA programs to reduce reliability risk from space radiation.

  12. XMM-Newton Detection of Hard X-ray Emission in the Nitrogen-Type Wolf-Rayet Star WR110

    E-print Network

    Skinner, S L; Güdel, M; Schmutz, W

    2002-01-01

    We have used the excellent sensitivity of XMM-Newton to obtain the first high-quality X-ray spectrum of a Wolf-Rayet (WR) star which is not known to be a member of a binary system. Our target, the nitrogen-type star WR 110 (= HD 165688) was also observed and detected with the VLA at four different frequencies. The radio data are in excellent agreement with that expected for free-free wind emission. and the ionized mass-loss rate is derived. The X-ray emission measure distribution shows a dominant contribution from cool plasma at kT$_{cool}$ = 0.5 keV (6 MK) which is only weakly absorbed. We argue that this cool emission originates at hundreds of radii if the wind is spherical and homogeneous and derive shock velocities and the X-ray filling factor using radiative shock models. A surprising result is the unambiguous detection of a hard X-ray component clearly seen in the hard-band images and the spectra. This hard component accounts for about half of the observed flux and can be acceptably fitted by a hot opti...

  13. Irradiation Effects on Diagnostic Components for ITER

    NASA Astrophysics Data System (ADS)

    Nishitani, Takeo; Shikama, Tatsuo; Reichel, Roger; Sugie, Tatsuo; Kakuta, Tsunemi; Kasai, Satoshi; Ishitsuka, Etsuo; Yamamoto, Shin

    Irradiation tests on many diagnostic components have been carried out as a part of the R&D program of the ITER Engineering Design Activities (EDA). Five kinds of ITER round robin fibers were irradiated in JMTR and60Co ?-rays. Induced transmission loss of those fibers are much smaller than that of pure SiO2 core fiber. Especially, KU-H2G from Russian Federation and F-doped fibers from Japan have rather good radiation hardness even in the visible range. Those fibers might be available in the diagnostic port of ITER. The transmissivity of KU-1 quartz, which is a candidate of the window material for UV and visible spectroscopy in ITER, was measured under the irradiation of 14 MeV neutrons and ?-rays in the UV range (200 - 400 nm). Significant transmission loss was observed in the wavelength range of 200-300 nm. The Mica substrate bolometer was irradiated in JMTR during three irradiation cycles. Total neutron fluence was about 1×1024 n/m2 which was equivalent to 0.1 dpa. Significant increase in the meander resistance was observed, which was causedby the nuclear transmutation of gold into mercury. The use of gold meanders might be problematic in ITER.

  14. Radiation Symbols

    MedlinePLUS

    Radiation Protection Basics Health Effects Ionizing & Non-Ionizing Radiation Understanding Radiation: Radiation Symbols Radiation Protection Basics Main Page History of Radiation Protection Radiation Warning Symbols Radiation Warning Sign Gallery ...

  15. Hardness ratio evolutionary curves of gamma-ray bursts expected by the curvature effect

    E-print Network

    Y. -P. Qin; C. -Y. Su; J. H. Fan; A. C. Gupta

    2007-01-04

    We have investigated the gamma-ray bursts pulses assumed to arise from relativistically expending fireballs. We find, due to the curvature effect, the evolutionary curve of the raw hardness ratio (when the background count is included) varies significantly, depending on the hardness of a burst. For a soft burst, an upside-down pulse of its raw hardness ratio curve (HRC) would be observed; for a hard burst, its raw HRC shows a pulse-like profile with a sinkage in its decaying phase; for a very hard burst, the raw HRC possesses a pulse-like profile without a sinkage in its decaying phase. For a pulse-like raw HRC as shown in the case of the hard and very hard bursts, its peak would appear in advance of that of the corresponding light curve. We have studied here the HRC of GRB 920216, GRB 920830 and GRB 990816 in detail. The features of the raw HRC expected in the hard burst are observed in these bursts. A fit to the three bursts shows that the curvature effect alone could indeed account for the predicted characteristics of HRCs. In addition, we find that the observed hardness ratio tends to be harder at the beginning of the pulses than what the curvature effect could predict and be softer at the late time of the pulses. We believe this is an evidence showing the existence of intrinsic hard-to-soft radiation.

  16. The Complexity of Hardness Amplification and Derandomization

    E-print Network

    Viola, Emanuele

    The Complexity of Hardness Amplification and Derandomization A thesis presented by Emanuele Viola Emanuele Viola The Complexity of Hardness Amplification and Derandomization Abstract This thesis studies of hardness amplification and deran­ domization. Hardness amplification is the task of taking a function

  17. Using Nondeterminism to Amplify Hardness Alexander Healy

    E-print Network

    Viola, Emanuele

    Using Nondeterminism to Amplify Hardness Alexander Healy Salil Vadhan Harvard University Emanuele Viola ABSTRACT We revisit the problem of hardness amplification in NP, as recently studied by O) , we amplify to hardness 1/2 - 1/n(1) . 2. If s(n) = 2n(1) , we amplify to hardness 1/2-1/2n(1) . 3

  18. Fabrication and characterization of fiber optical components for application in guiding, sensing and molding of THz and mid-IR radiation

    NASA Astrophysics Data System (ADS)

    Mazhorova, Anna

    The terahertz (THz) range refers to electromagnetic waves with frequencies between 100 GHz and 10 THz, or wavelengths between 3 mm and 30 µm. Light between radio waves and infrared has some unique properties. Within the scope of this work I would like to address three main research topics. In Chapter 2, I describe fabrication method and THz characterization of composite films containing either aligned metallic (tin alloy) microwires or chalcogenide As2Se3 microwires. The microwire arrays are made by stack-and-draw fiber fabrication technique using multi-step co-drawing of low-melting-temperature metals or semiconductor glasses together with polymers. Fibers are then stacked together and pressed into composite films. Transmission through metamaterial films is studied in the whole THz range (0.1-20 THz) using a combination of FTIR and TDS. Metal containing metamaterials are found to have strong polarizing properties, while semiconductor containing materials are polarization independent and could have a designable high refractive index. Using the transfer matrix theory, it was shown how to retrieve the complex polarization dependent refractive index of the composite films. We then detail the selfconsistent algorithm for retrieving the optical properties of the metal alloy used in the fabrication of the metamaterial layers by using an effective medium approximation. Finally, we study challenges in fabrication of metamaterials with sub-micrometer metallic wires by repeated stack-and-draw process by comparing samples made using 2, 3 and 4 consecutive drawings. When using metallic alloys we observe phase separation effects and nano-grids formation on small metallic wires. In Chapter 3, we have studied fabrication and bacteria detection application of the lowloss subwavelength THz microstructured fibers. One of the key difficulties in the design of terahertz waveguides lies in the fact that almost all materials are highly absorbing in the terahertz region. Since the lowest absorption loss occurs in dry gases, an efficient waveguide design must maximize the fraction of power guided in the gas. Different types of THz waveguides have been proposed based on this concept including a subwavelength waveguide featuring a core with a size much smaller than the wavelength of light in which a large fraction of the guided light is found outside of the lossy core region. A practical design of such a waveguide was recently proposed in our research group and presents a subwavelength fiber suspended on thin bridges in the middle of a larger protective tube. Large channels formed by the bridges and a tube make a convenient opto-microfluidic system that is easy to fill with liquid analytes or purge with dry gases. Particularly, the THz subwavelength waveguide used in our experiments features a 150 µm core fiber suspended by three 20 µm-thick bridges in the center of a 5.1 mm diameter tube of 4 cm in length. This waveguide design presents several important advantages for bio-sensing applications. First, the waveguide structure allows direct and convenient access to the fiber core and to the evanescent wave guided around it. Second, the outer cladding effectively isolates the core-guided mode from the surrounding environment, (e.g. fiber holders), thereby preventing the undesirable external perturbations of the terahertz signal. Finally, in Chapter 4, low-loss chalcogenide capillary-based waveguides that operate both in the mid-IR and THz spectral ranges are investigated. Chalcogenide glasses have attracted strong interest in a view of optical applications in the near-IR and mid-IR spectral ranges (1-14 µm) due to their relatively low losses and high nonlinearities. Furthermore, chalcogenide glass-based microstructured fibers open many interesting possibilities for a large number of applications in the mid-IR spectral range, where applications in optical sensing, supercontinuum generation and single-mode propagation of IR light, transmission of the CO and CO2 laser radiation have already been demonstrated. We believe that chalcogenide glasses c

  19. Enhanced Low Dose Rate Effects in Bipolar Circuits: A New Hardness Assurance Problem for NASA

    NASA Technical Reports Server (NTRS)

    Johnston, A.; Barnes, C.

    1995-01-01

    Many bipolar integrated circuits are much more susceptible to ionizing radiation at low dose rates than they are at high dose rates typically used for radiation parts testing. Since the low dose rate is equivalent to that seen in space, the standard lab test no longer can be considered conservative and has caused the Air Force to issue an alert. Although a reliable radiation hardness assurance test has not yet been designed, possible mechanisms for low dose rate enhancement and hardness assurance tests are discussed.

  20. Automated laser fabrication of cemented carbide components

    NASA Astrophysics Data System (ADS)

    Paul, C. P.; Khajepour, A.

    2008-07-01

    Automated Laser Fabrication (ALFa) is one of the most rapidly growing rapid-manufacturing technologies. It is similar to laser cladding at process level with different end applications. In general, laser cladding technique is used to deposit materials on the substrate either to improve the surface properties or to refurbish the worn-out parts, while ALFa is capable of near net shaping the components by layer-by-layer deposition of the material directly from CAD model. This manufacturing method is very attractive for low volume manufacturing of hard materials, as near net shaping minimizes machining of hard material and subsequently brings significant savings in time and costly material. To date, many researchers have used this technology to fabricate components using various alloy steels, nickel-based alloys and cobalt-based alloys. In the present study, the work is extended to tungsten carbide cobalt (WC-Co) composites. A set of comprehensive experiments was carried out to study the effect of processing parameters during multi-layer fabrication. The process parameters were optimized for the component-level fabrication. Fabricated components were subjected to dye-penetrant testing, three-point flexural testing, hardness measurement, optical and scanning electron microscopy and X-ray diffraction analysis. The test results revealed that the laser-fabricated material was defect free and more ductile in nature. Thus, ALFa technology, not only produced the quality components, but also minimized machining of hard material and brought significant saving of time and costly WC-Co material.

  1. Automated measurement system employing eddy currents to adjust probe position and determine metal hardness

    DOEpatents

    Prince, James M. (Kennewick, WA); Dodson, Michael G. (Richland, WA); Lechelt, Wayne M. (Benton City, WA)

    1989-01-01

    A system for measuring the hardness of cartridge cases employs an eddy current probe for inducing and sensing eddy currents in each cartridge case. A first component of the sensed signal is utilized in a closed loop system for accurately positioning the probe relative to the cartridge case both in the lift off direction and in the tangential direction, and a second component of the sensed signal is employed as a measure of the hardness. The positioning and measurement are carried out under closed loop microprocessor control facilitating hardness testing on a production line basis.

  2. Automated measurement system employing eddy currents to adjust probe position and determine metal hardness

    DOEpatents

    Prince, J.M.; Dodson, M.G.; Lechelt, W.M.

    1989-07-18

    A system for measuring the hardness of cartridge cases employs an eddy current probe for inducing and sensing eddy currents in each cartridge case. A first component of the sensed signal is utilized in a closed loop system for accurately positioning the probe relative to the cartridge case both in the lift off direction and in the tangential direction, and a second component of the sensed signal is employed as a measure of the hardness. The positioning and measurement are carried out under closed loop microprocessor control facilitating hardness testing on a production line basis. 14 figs.

  3. Radiation Assurance for the Space Environment

    NASA Technical Reports Server (NTRS)

    Barth, Janet L.; LaBel, Kenneth A.; Poivey, Christian

    2004-01-01

    The space radiation environment can lead to extremely harsh operating conditions for spacecraft electronic systems. A hardness assurance methodology must be followed to assure that the space radiation environment does not compromise the functionality and performance of space-based systems during the mission lifetime. The methodology includes a definition of the radiation environment, assessment of the radiation sensitivity of parts, worst-case analysis of the impact of radiation effects, and part acceptance decisions which are likely to include mitigation measures.

  4. Structure and hardness of materials after electron bombardment

    Microsoft Academic Search

    M. M. Krasnoshchekov; A. E. Speshinskii; E. A. Markovskii

    1978-01-01

    1.As the result of electron bombardment there are substantial changes in the structure and properties of Armco iron and steel 45 due simultaneously to thermal and radiation effects.2.After irradiation, the hardness of Armco iron reaches HV 180, annealed steel 45 HV 300, and normalized steel 45 HV 540.3.The microhardness in the section of the sample along the axis of the

  5. Hard diffraction and rapidity gaps

    SciTech Connect

    Brandt, A.

    1995-09-01

    The field of hard diffraction, which studies events with a rapidity gap and a hard scattering, has expanded dramatically recently. A review of new results from CDF, D{O}, H1 and ZEUS will be given. These results include diffractive jet production, deep-inelastic scattering in large rapidity gap events, rapidity gaps between high transverse energy jets, and a search for diffractive W-boson production. The combination of these results gives new insight into the exchanged object, believed to be the pomeron. The results axe consistent with factorization and with a hard pomeron that contains both quarks and gluons. There is also evidence for the exchange of a strongly interacting color singlet in high momentum transfer (36 < {vert_bar}t{vert_bar} < 1000 GeV{sup 2}) events.

  6. Hard Color Coherent Phenomena in Dis

    NASA Astrophysics Data System (ADS)

    Frankfurt, Leonid; Strikman, Mark

    1998-04-01

    We review two new types of hard diffractive processes calculable in QCD: exclusive production of light mesons in the Bjorken limit by longitudinal photons [1-3], exclusive photo and electro production of heavy onium states [2,4], and diffraction of pions (protons) off nucleons into two (three) jets. Both types of processes measure minimal light-cone Fock space components of the hadron wave functions [5]. Generalization of QCD factorization theorem to hard diffractive processes will be explained [3]. We also briefly summarize experimental evidence for onset of perturbative QCD regime in exclusive vector meson production at HERA, and in pion diffraction into two jets from FNAL will be presented. [1] S. J. Brodsky, L. Frankfurt, J. F. Gunion, A. H. Mueller and M. Strikman, Phys. Rev. D50 (1994) 3134. [2] L. Frankfurt, W. Koepf, M.Strikman, Phys. Rev. D54 (1996) 1996. [3] J.C.Collins,L.Frankfurt and M.Strikman,Phys.Rev. D56 (1997)2982. [4] L. Frankfurt, W. Koepf, M.Strikman, Phys.Rev. D57(1998)512. [5] L. Frankfurt, G.A. Miller, M. Strikman, Phys.Lett.B304 (1993)1.

  7. Ordering of hard spheres inside hard cylindrical pores.

    PubMed

    Durán-Olivencia, F J; Gordillo, M C

    2009-06-01

    Isothermal-isobaric simulations on the ordering behavior of hard spheres upon confinement are presented. The radii of the confining cylinders go from 1.1 to 2 in units of the diameters of the hard spheres adsorbed. In all the range of pressures considered the spheres were located in concentric layers, as many as the radius of the hard cylinder would permit. When the pressure increases, the hard spheres go from being loosely arranged to the formation of ordered structures. This change is marked in all cases by a distinct break in the density of spheres in a narrow pressure range. When the tube radius is smaller than 1.5, the high-pressure ordering is determined by the number of coplanar spheres you can have within a circle of radius equal to that of the confining tube. For wider tubes, the change upon compression is determined by the formation of defected two-dimensional triangular lattices wrapped to fit inside the particular cylinder we are considering. PMID:19658477

  8. Hard diffraction -- 20 years later

    E-print Network

    Gunnar Ingelman

    2005-12-12

    The idea of diffractive processes with a hard scale involved, to resolve the underlying parton dynamics, was published 1985 and experimentally verified 1988. Today hard diffraction is an active research field with high-quality data and new theoretical models. The trend from Regge-based pomeron models to QCD-based parton level models has given insights on QCD dynamics involving perturbative gluon exchange mechanisms, including the predicted BFKL-dynamics, as well as novel ideas on non-perturbative colour fields and their interactions. Extrapolations to the LHC include the interesting possibility of diffractive Higgs production.

  9. Hardness of ion implanted ceramics

    SciTech Connect

    Oliver, W.C.; McHargue, C.J.; Farlow, G.C.; White, C.W.

    1985-01-01

    It has been established that the wear behavior of ceramic materials can be modified through ion implantation. Studies have been done to characterize the effect of implantation on the structure and composition of ceramic surfaces. To understand how these changes affect the wear properties of the ceramic, other mechanical properties must be measured. To accomplish this, a commercially available ultra low load hardness tester has been used to characterize Al/sub 2/O/sub 3/ with different implanted species and doses. The hardness of the base material is compared with the highly damaged crystalline state as well as the amorphous material.

  10. Hard X-rays from hybrid X pinches

    NASA Astrophysics Data System (ADS)

    Shelkovenko, T. A.; Pikuz, S. A.; Hoyt, C. L.; Cahill, A. D.; Hammer, D. A.; Tilikin, I. N.; Mingaleev, A. R.; Agafonov, A. V.

    2014-12-01

    X pinches are well known to produce very small, dense plasma pinches ("hot spots") that emit short bursts of 1.5-8 keV radiation. Hard X-ray radiation in the 8-100 keV range is also emitted, only a small portion of which is associated with the X-pinch hot spot. In hybrid X-pinches, the "long" X-ray pulse is terminated by fast closure of the gap between the two conical electrodes by rapidly expanding electrode plasmas. The temporal, spectral, and spatial properties of this higher energy radiation, 10 - 60 keV, have been studied. This radiation was used for point-projection imaging with magnification between 1.5 and 3, and spatial resolution less than100 micrometers was demonstrated.

  11. Semiconductor radiation detector

    DOEpatents

    Bell, Zane W. (Oak Ridge, TN); Burger, Arnold (Knoxville, TN)

    2010-03-30

    A semiconductor detector for ionizing electromagnetic radiation, neutrons, and energetic charged particles. The detecting element is comprised of a compound having the composition I-III-VI.sub.2 or II-IV-V.sub.2 where the "I" component is from column 1A or 1B of the periodic table, the "II" component is from column 2B, the "III" component is from column 3A, the "IV" component is from column 4A, the "V" component is from column 5A, and the "VI" component is from column 6A. The detecting element detects ionizing radiation by generating a signal proportional to the energy deposited in the element, and detects neutrons by virtue of the ionizing radiation emitted by one or more of the constituent materials subsequent to capture. The detector may contain more than one neutron-sensitive component.

  12. Biology of the hard clam Hard clams of the genus Mercenaria

    E-print Network

    Florida, University of

    Biology of the hard clam Hard clams of the genus Mercenaria are found from the Gulf of St. Lawrence of the general- izations may apply to all hard clams. The hard clam is rarely found where salinities average less than 20 parts per thousand (ppt). Hard clams occu- py intertidal and subtidal habitats, where

  13. Spherical reference systems for nonspherical hard interactions

    SciTech Connect

    Williams, G.O.; Lebowitz, J.L.; Percus, J.K.

    1984-12-20

    Results are presented on three complex systems of hard molecules: linear triatomics, heteronuclear dumbbells, and two-component mixtures of dumbbells. In addition to studying the equation of state generated by the median potential, the Barker-Henderson reference system is also investigated and seen to give results nearly indistinguishable from those obtained from the median system. Both reference systems continue to reproduce the bulk thermodynamics of the true systems moderately well. Both reference potentials are found to be approximately additive when applied to mixtures. These results continue to suggest that either of these two reference systems may form the basis of a successful perturbation theory for fluids of nonspherical molecules. 15 references, 5 figures, 9 tables.

  14. Dynamic indentation hardness of materials

    NASA Astrophysics Data System (ADS)

    Koeppel, Brian James

    Indentation hardness is one of the simplest and most commonly used measures for quickly characterizing material response under static loads. Hardness may mean resistance to cutting to a machinist, resistance to wear to a tribologist, or a measure of flow stress to a design engineer. In this simple technique, a predetermined force is applied to an indenter for 5-30 seconds causing it to penetrate a specimen. By measuring the load and the indentation size, a hardness value is determined. However, the rate of deformation during indenter penetration is of the order of 10sp{-4}\\ ssp{-1}. In most practical applications, such as high speed machining or impact, material deforms at strain rates in excess of 10sp3{-}10sp5\\ ssp{-1}. At such high rates, it is well established that the plastic behavior of materials is considerably different from their static counterpart. For example, materials exhibit an increase in their yield stress, flow stress, fracture stress, and fracture toughness at high strain rates. Hence, the use of static hardness as an indicator of material response under dynamic loads may not be appropriate. Accordingly, a simple dynamic indentation hardness tester is developed for characterizing materials at strain rates similar to those encountered in realistic situations. The experimental technique uses elastic stress wave propagation phenomena in a slender rod. The technique is designed to deliver a single indentation load of 100-200 mus duration. Similar to static measurements, the dynamic hardness is determined from the measured load and indentation size. Hardness measurements on a range of metals have revealed that the dynamic hardness is consistently greater than the static hardness. The increase in hardness is strongly dependent on the crystal structure of the material. The observed trends in hardness are also found to be consistent with the yield and flow stresses of these materials under uniaxial compression. Therefore, it is suggested that the current technique can be used to assess the rate sensitive nature of engineering materials. To further characterize the plastic strains within the indentation volume, static microhardness measurements were also performed within this region. The contours of microhardness indicated that the plastic zone beneath the indenter is typically smaller under dynamic conditions compared to static loading for rate sensitive materials. To assess the influence of the elastic modulus, yield stress, and work hardening coefficient on the induced plastic volume, finite element simulations were performed using the explicit finite element code LS-DYNA3D. The parametric study revealed that the yield stress has the most significant influence on the size and shape of the plastic zone. The above microstructural and numerical results can be used as guidelines for proper selection and design of engineering materials in applications involving high strain rate loading. Moreover, the contours of microhardness variation can be used to verify the suitability of analytical models developed for characterizing the deformation behavior of engineering materials under complex three dimensional loads.

  15. Microcircuit radiation effects databank

    NASA Technical Reports Server (NTRS)

    1983-01-01

    This databank is the collation of radiation test data submitted by many testers and serves as a reference for engineers who are concerned with and have some knowledge of the effects of the natural radiation environment on microcircuits. It contains radiation sensitivity results from ground tests and is divided into two sections. Section A lists total dose damage information, and section B lists single event upset cross sections, I.E., the probability of a soft error (bit flip) or of a hard error (latchup).

  16. Non-destructive component separation using infrared radiant energy

    DOEpatents

    Simandl, Ronald F. (Knoxville, TN); Russell, Steven W. (Knoxville, TN); Holt, Jerrid S. (Knoxville, TN); Brown, John D. (Harriman, TN)

    2011-03-01

    A method for separating a first component and a second component from one another at an adhesive bond interface between the first component and second component. Typically the method involves irradiating the first component with infrared radiation from a source that radiates substantially only short wavelengths until the adhesive bond is destabilized, and then separating the first component and the second component from one another. In some embodiments an assembly of components to be debonded is placed inside an enclosure and the assembly is illuminated from an IR source that is external to the enclosure. In some embodiments an assembly of components to be debonded is simultaneously irradiated by a multi-planar array of IR sources. Often the IR radiation is unidirectional. In some embodiments the IR radiation is narrow-band short wavelength infrared radiation.

  17. FATIGUE OF BIOMATERIALS: HARD TISSUES.

    PubMed

    Arola, D; Bajaj, D; Ivancik, J; Majd, H; Zhang, D

    2010-09-01

    The fatigue and fracture behavior of hard tissues are topics of considerable interest today. This special group of organic materials comprises the highly mineralized and load-bearing tissues of the human body, and includes bone, cementum, dentin and enamel. An understanding of their fatigue behavior and the influence of loading conditions and physiological factors (e.g. aging and disease) on the mechanisms of degradation are essential for achieving lifelong health. But there is much more to this topic than the immediate medical issues. There are many challenges to characterizing the fatigue behavior of hard tissues, much of which is attributed to size constraints and the complexity of their microstructure. The relative importance of the constituents on the type and distribution of defects, rate of coalescence, and their contributions to the initiation and growth of cracks, are formidable topics that have not reached maturity. Hard tissues also provide a medium for learning and a source of inspiration in the design of new microstructures for engineering materials. This article briefly reviews fatigue of hard tissues with shared emphasis on current understanding, the challenges and the unanswered questions. PMID:20563239

  18. Playing the Numbers: Hard Choices

    ERIC Educational Resources Information Center

    Doyle, William R.

    2009-01-01

    Stateline.org recently called this recession the worst in 50 years for state budgets. As has been the case in past economic downturns, higher education looks to be particularly hard hit. Funds from the American Recovery and Relief Act may have postponed some of the difficulty for many colleges and universities, but the outlook for public higher…

  19. Materials science Nanotubes get hard

    E-print Network

    Downs, Robert T.

    Materials science Nanotubes get hard under pressure Proc. Natl Acad. Sci. USA doi:10.1073/pnas.0405877101 (2004) When Zhongwu Wang et al. squeezed carbon nanotubes in a diamond anvil cell, they made nanotubes into diamond itself: the carbon material formed under compression at room temperature seems

  20. Is Carbon Hard or Soft?

    NSDL National Science Digital Library

    The representation shows differences in the arrangement of carbon atoms that make up diamonds and graphite. Through text and pictures, the resource describes the difference in arrangement of two different carbon allotropes. The text relates the differences in arrangements to differences in the hardness (properties) of the materials.

  1. Hard electroproduction of vector mesons

    E-print Network

    P. Kroll

    2008-06-16

    It is reported on a global analysis of hard vector-meson electroproduction which is based on the handbag factorization. The generalized parton distributions are constructed from their forward limits with the help of double distributions and the partonic subprocesses are calculated within the modified perturbative approach.

  2. Kinetics of hardness evolution during annealing of gamma-irradiated polycarbonate

    SciTech Connect

    Yeh, S. H.; Chen, P. Y.; Lee, Sanboh [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Harmon, Julie [Department of Chemistry, University of South Florida, Tampa, Florida 33620-5250 (United States)

    2012-12-01

    This study focuses on the evolution in microhardness values that accompany isothermal annealing in gamma-irradiated polycarbonate (PC). Hardness increases with increasing annealing time, temperature, and gamma radiation dose. A model composed of a mixture of first and zero order structure relaxation is proposed to interpret the hardness data. The rate constant data fit the Arrhenius equation, and the corresponding activation energy decreases with increasing dose. The extent of structural relaxation that controls the hardness in post-annealed PC increases with increasing annealing temperature and dose. The model demonstrates that hardness evolution in PC is an endothermic process. By contrast, when the model is applied to irradiated poly(methyl methacrylate) and hydroxyethyl methacrylate copolymer, hardness evolution is an exothermic process.

  3. Hard scattering and QCD Fundamentals at RHIC

    E-print Network

    M. J. Tannenbaum

    2008-06-02

    In 1998, at the 4th QCD workshop, Rolf Baier asked me whether jets could be measured in Au+Au collisions because he had a prediction of a QCD medium-effect (energy loss via soft gluon radiation induced by multiple scattering) on color-charged partons traversing a hot-dense-medium composed of screened color-charges. I reviewed the possibilities in a talk explaining that there was a general consensus that for Au+Au central collisions at $\\sqrt{s_{NN}}=200$ GeV, leading particles are the only way to find jets because of the large particle density. The good news was that hard-scattering in p-p collisions was originally observed by the method of leading particles and that these techniques could be used to study hard-scattering and jets in Au+Au collisions. Notably, I described ``How everything you want to know about jets can be found using 2-particle correlations''. In fact, the predicted ``jet quenching'' and other new phenomena were discovered by this method. However, this past year, I had to soften the statement to {\\em almost everything} because we found by explicit calculation in PHENIX that the away-side two-particle correlation $p_{T_a}$ spectrum from a $\\pi^0$ trigger with $p_{T_t}$ is not sensitive to the fragmentation function--overturning a belief dating from the seminal paper of Feynman, Field and Fox in 1977. A new formula was derived which showed that the shape of the $p_{T_a}$ spectrum depends only on the power $n$ of the parton invariant cross section so that NLO pQCD calculations of the two particle away-side correlations are, in fact, less sensitive to the shape of the fragmentation function than calculations of the inclusive $\\pi^0$ cross section.

  4. A first-principles approach to total-dose hardness assurance

    SciTech Connect

    Fleetwood, D.M. [Sandia National Labs., Albuquerque, NM (United States). Radiation Technology and Assurance Dept.

    1995-11-01

    A first-principles approach to radiation hardness assurance was described that provides the technical background to the present US and European total-dose radiation hardness assurance test methods for MOS technologies, TM 1019.4 and BS 22900. These test methods could not have been developed otherwise, as their existence depends not on a wealth of empirical comparisons of IC data from ground and space testing, but on a fundamental understanding of MOS defect growth and annealing processes. Rebound testing should become less of a problem for advanced MOS small-signal electronics technologies for systems with total dose requirements below 50--100 krad(SiO{sub 2}) because of trends toward much thinner gate oxides. For older technologies with thicker gate oxides and for power devices, rebound testing is unavoidable without detailed characterization studies to assess the impact of interface traps on devices response in space. The QML approach is promising for future hardened technologies. A sufficient understanding of process effects on radiation hardness has been developed that should be able to reduce testing costs in the future for hardened parts. Finally, it is hoped that the above discussions have demonstrated that the foundation for cost-effective hardness assurance tests is laid with studies of the basic mechanisms of radiation effects. Without a diligent assessment of new radiation effects mechanisms in future technologies, one cannot be assured that the present generation of radiation test standards will continue to apply.

  5. Leptonic tensor for hard photon emission in annihilation channel.Dirac tensor with heavy photon

    E-print Network

    V. V. Bytev; E. A. Kuraev; E. S. Scherbakova

    2012-02-01

    For the large-angles hard photon emission by initial leptons in process of high energy annihilation of $e^+ e^- \\to $ to hadrons the Dirac tensor is obtained, taking into account the lowest order radiative corrections. The case of large-angles emission of two hard photons by initial leptons is considered. This result is being completed by the kinematics case of collinear hard photons emission as well as soft virtual and real photons and can be used for construction of Monte-Carlo generators.

  6. Rapidity Gaps in Hard Photoproduction

    E-print Network

    L. E. Sinclair

    1996-06-18

    Recent results obtained from studies of diffractive processes in hard photoproduction performed by the ZEUS collaboration using data delivered by HERA in 1993 and 1994 are presented. In particular, we have found that $(7 \\pm 3)$\\% of events with two jets at a pseudorapidity interval of 3.5 to 4 are inconsistent with a non-diffractive production mechanism. These events may be interpreted as arising due to the exchange of a colour singlet object of negative squared invariant mass ($-t$) around 40~GeV$^2$. We have also probed the structure of the exchanged colour singlet object in low--$t$ diffractive scattering. By comparing the results from photoproduction and electroproduction processes we find that between 30\\% and 80\\% of the momentum of the exchanged colour singlet object which is carried by partons is due to hard gluons.

  7. Why Are Drugs So Hard to Quit?

    MedlinePLUS Videos and Cool Tools

    Video: Why Are Drugs So Hard to Quit? Your browser does not support inline frames or is currently configured not to display inline ... link under the video: In English: Why Are Drugs So Hard to Quit? En español: ¿Por Qué ...

  8. Measurements of the hard-x-ray reflectivity of iridium

    SciTech Connect

    Romaine, S.; Bruni, R.; Gorenstein, P.; Zhong, Z

    2007-01-10

    In connection with the design of a hard-x-ray telescope for the Constellation X-Ray Observatory we measured the reflectivity of an iridium-coated zerodur substrate as a function of angle at 55, 60, 70, and 80 keV at the National Synchrotron Light Source of Brookhaven National Laboratory. The optical constants were derived from the reflectivity data. The real component of the index of refraction is in excellent agreement with theoretical values at all four energies. However, the imaginary component, which is related to the mass attenuation coefficient, is 50% to 70% larger at 55, 60, and 70 keV than theoretical values.

  9. CMS Results on Hard Diffraction

    E-print Network

    Christina Mesropian on behalf of the CMS collaboration

    2013-10-20

    In these proceedings we present CMS results on hard diffraction. Diffractive dijet production in pp collisions at $\\sqrt{s}$=7 TeV is discussed. The cross section for dijet production is presented as a function of $\\tilde{\\xi}$, representing the fractional momentum loss of the scattered proton in single-diffractive events. The observation of W and Z boson production in events with a large pseudo-rapidity gap is also presented.

  10. Microwave assisted hard rock cutting

    DOEpatents

    Lindroth, David P. (Apple Valley, MN); Morrell, Roger J. (Bloomington, MN); Blair, James R. (Inver Grove Heights, MN)

    1991-01-01

    An apparatus for the sequential fracturing and cutting of subsurface volume of hard rock (102) in the strata (101) of a mining environment (100) by subjecting the volume of rock to a beam (25) of microwave energy to fracture the subsurface volume of rock by differential expansion; and , then bringing the cutting edge (52) of a piece of conventional mining machinery (50) into contact with the fractured rock (102).

  11. Development of a fast radiation detector based on barium fluoride scintillation crystal

    SciTech Connect

    Han, Hetong [Northwest Institute of Nuclear Technology, NINT, Xi'an 710024, Shaanxi (China) [Northwest Institute of Nuclear Technology, NINT, Xi'an 710024, Shaanxi (China); School of Nuclear Science and Technology, Xi'an Jiaotong University, XJTU, Xi'an 710049, Shaanxi (China); Zhang, Zichuan; Weng, Xiufeng; Liu, Junhong; Zhang, Kan; Li, Gang [Northwest Institute of Nuclear Technology, NINT, Xi'an 710024, Shaanxi (China)] [Northwest Institute of Nuclear Technology, NINT, Xi'an 710024, Shaanxi (China); Guan, Xingyin [School of Nuclear Science and Technology, Xi'an Jiaotong University, XJTU, Xi'an 710049, Shaanxi (China)] [School of Nuclear Science and Technology, Xi'an Jiaotong University, XJTU, Xi'an 710049, Shaanxi (China)

    2013-07-15

    Barium fluoride (BaF{sub 2}) is an inorganic scintillation material used for the detection of X/gamma radiation due to its relatively high density, equivalent atomic number, radiation hardness, and high luminescence. BaF{sub 2} has a potential capacity to be used in gamma ray timing experiments due to the prompt decay emission components. It is known that the light output from BaF{sub 2} has three decay components: two prompt of those at approximately 195 nm and 220 nm with a decay constant around 600-800 ps and a more intense, slow component at approximately 310 nm with a decay constant around 630 ns which hinders fast timing experiments. We report here the development of a fast radiation detector based on a BaF{sub 2} scintillation crystal employing a special optical filter device, a multiple reflection multi-path ultraviolet region short-wavelength pass light guides (MRMP-short pass filter) by using selective reflection technique, for which the intensity of the slow component is reduced to less than 1%. The methods used for this study provide a novel way to design radiation detector by utilizing scintillation crystal with several emission bands.

  12. Hard Determinism and the Moral "Ought"

    E-print Network

    Kuo, Lenore

    HARD DETERMINISM AND THE MORAL 'OUGHT' LENORE KUO The University of Nebraska at Omaha Philosophers from Aristotle to vanlnwagen 1 have questioned the possibility of preserving ethics if hard determinism is true. Thus it has been argued that we... must reject hard determinism because of the apparent "violence" it does to our basic conception of morality. For example, Howard Hintz maintains that: [Hard determinism) destroys the foundations of all prescriptive ethics except on the arbitrary...

  13. Component Rhinoplasty

    PubMed Central

    Mohmand, Muhammad Humayun; Ahmad, Muhammad

    2014-01-01

    BACKGROUND According to statistics of American Society of Plastic Surgeons, cosmetic rhinoplasty was the second most frequently performed cosmetic surgery. This study shares the experiences with component rhinoplasty. METHODS From 2004 to 2010, all patients underwent aesthetic nasal surgery were enrolled. The patients requiring only correction of septal deviation and those presenting with cleft lip nasal deformity were excluded. All procedures were performed under general anaesthesia with open technique using transcolumellar and infra-cartilageous incisions. The transculomelalr incision was closed with 6-0 polypropylene and infra-cartilagenous incisions by 5-0 absorbable sutures. Non-absorbable sutures were removed on the fifth postoperative day. The septum was fixed by ‘quilting sutures’. Both nostrils were packed with antibiotic ointment containing paraffin gauzes which were removed after 24-48 hours. External nasal splint was applied to be removed on the fifth postoperative day. RESULTS A total of 191 patients were enrolled (male:female ratio=1:1.47). The mean age of female patients was 25.3 years and 29.4 years in males. Among 50.8% of patients, the cause of deformity was not known. Only 21.5% patients had a positive history of trauma. Majority of patients (90.6%) underwent septoplasty. Twenty percent of surgeries were secondary. Spreader grafts were used in 85% of patients. In 11% of patients, conchal grafts were used. For none of patients, the inferior turbinectomy was performed. No case of costal cartilage graft or silicone implant was used. Only 5.6% of patients had redo-surgeries. No abnormal scarring was noted during follow-up. CONCLUSIONS Dorsal hump reduction can be recommended with accuracy and safety without compromising the nasal airway. PMID:25489519

  14. Hard Cider Varieties Suitable for Northern

    E-print Network

    Center #12;Hard Cider Planting at NWMHRC · Planted in 2001 and 2002 · First apples in fall 2004 ­ Most fermented 25 varieties #12;Hard Cider Apples · Cider apples are similar to wine grapes--their qualities are only noteworthy when made into wine or hard cider · Cider apples have flavor characteristics acquired

  15. DISTRIBUTED VERIFICATION AND HARDNESS OF DISTRIBUTED APPROXIMATION

    E-print Network

    DISTRIBUTED VERIFICATION AND HARDNESS OF DISTRIBUTED APPROXIMATION ATISH DAS SARMA, STEPHAN HOLZER on the hardness of distributed approximation for many classical optimization problems including minimum spanning the previous hardness of approximation bound of Elkin [STOC 2004] as well as the lower bound for (exact) MST

  16. Distributed Verification and Hardness of Distributed Approximation

    E-print Network

    Distributed Verification and Hardness of Distributed Approximation Atish Das Sarma Google Foundation (BSF). Permission to make digital or hard copies of all or part of this work for personal on the hardness of distributed approxi- mation for many classical optimization problems including minimum spanning

  17. Empirical Hardness Models for Combinatorial Auctions

    E-print Network

    Shoham, Yoav

    Chapter 19 Empirical Hardness Models for Combinatorial Auctions Kevin Leyton-Brown, Eugene Nudelman and Yoav Shoham In this chapter we consider the empirical hardness of the winner determination problem. We to learn, evaluate and interpret a function from these features to the predicted hardness of an instance

  18. Artificially soft and hard surfaces in electromagnetics

    Microsoft Academic Search

    Per-Simon Kildal

    1990-01-01

    A transversely corrugated surface as used in corrugated horn antennas represents a soft boundary. A hard boundary is made by using longitudinal corrugations filled with dielectric material. The concept of soft and hard surfaces is treated in detail, considering different geometries. It is shown that both the hard and soft boundaries have the advantage of a polarization-independent reflection coefficient for

  19. Using Nondeterminism to Amplify Hardness Alexander Healy

    E-print Network

    Viola, Emanuele

    Using Nondeterminism to Amplify Hardness Alexander Healy Salil Vadhan Division of Engineering revisit the problem of hardness amplification in NP, as recently studied by O'Donnell (JCSS `04). We prove to compute f on a 1/2 - 1/s (n) fraction of inputs. In particular, 1. If s(n) = n(1) , we amplify to hardness

  20. Using Nondeterminism to Amplify Hardness Alexander Healy

    E-print Network

    Vadhan, Salil

    Using Nondeterminism to Amplify Hardness Alexander Healy Salil Vadhan Division of Engineering revisit the problem of hardness amplification in NP, as recently studied by O'Donnell (STOC `02). We prove to compute f on a 1/2 - 1/s (n) fraction of inputs. In particular, 1. If s(n) = n(1) , we amplify to hardness

  1. Texts in Computational Complexity: Amplification of Hardness

    E-print Network

    Goldreich, Oded

    Texts in Computational Complexity: Amplification of Hardness Oded Goldreich Department of Computer a positive side, because hard problem can be ``put to work'' to our benefit, most notably in cryptography. One key issue that arises whenever one tries to utilize hard problem is bridging the gap between

  2. Hard Metric from Cayley Graphs Yuri Rabinovich

    E-print Network

    Newman, Ilan

    Hard Metric from Cayley Graphs Yuri Rabinovich Haifa University Joint work with Ilan Newman #12;Metric distortion and hard metrics The distortion of embedding a metric µ into an Euclidean space, c2(µ] and AR[98] claims that there exists metrics µ such that c2(µ)= (log n). We call such metrics hard. #12

  3. Hardness Amplification within NP against Deterministic Algorithms

    E-print Network

    Guruswami, Venkatesan

    Hardness Amplification within NP against Deterministic Algorithms Parikshit Gopalan Microsoft Carnegie Mellon University. Abstract We study the average-case hardness of the class NP against algorithms these classes, namely we ask: How hard are languages in NP on average for deterministic polynomial time

  4. Input Locality and Hardness Amplification Andrej Bogdanov

    E-print Network

    Rosen, Alon

    Input Locality and Hardness Amplification Andrej Bogdanov Alon Rosen Abstract We establish new hardness amplification results for one-way functions in which each input bit influences only a small number is injective then it is equally hard to invert f on a (1 - )-fraction of inputs. · If f is regular

  5. Kernelization hardness of connectivity problems Michal Pilipczuk

    E-print Network

    Fomin, Fedor V.

    Kernelization hardness of connectivity problems Michal Pilipczuk Faculty of Mathematics, Computer Science and Mechanics University of Warsaw 10th November 2010 Michal Pilipczuk Kernelization hardness of connectivity problems 1/13 #12;Source Kernelization hardness of connectivity problems in d-degenerate graphs WG

  6. 30 CFR 57.15002 - Hard hats.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2012-07-01 false Hard hats. 57.15002 Section 57.15002 Mineral...Surface and Underground § 57.15002 Hard hats. All persons shall wear suitable hard hats when in or around a mine or plant where...

  7. 30 CFR 57.15002 - Hard hats.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 false Hard hats. 57.15002 Section 57.15002 Mineral...Surface and Underground § 57.15002 Hard hats. All persons shall wear suitable hard hats when in or around a mine or plant where...

  8. 30 CFR 57.15002 - Hard hats.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false Hard hats. 57.15002 Section 57.15002 Mineral...Surface and Underground § 57.15002 Hard hats. All persons shall wear suitable hard hats when in or around a mine or plant where...

  9. 30 CFR 56.15002 - Hard hats.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2012-07-01 false Hard hats. 56.15002 Section 56.15002 Mineral...MINES Personal Protection § 56.15002 Hard hats. All persons shall wear suitable hard hats when in or around a mine or plant where...

  10. 30 CFR 57.15002 - Hard hats.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 2010-07-01 false Hard hats. 57.15002 Section 57.15002 Mineral...Surface and Underground § 57.15002 Hard hats. All persons shall wear suitable hard hats when in or around a mine or plant where...

  11. 30 CFR 56.15002 - Hard hats.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 2011-07-01 false Hard hats. 56.15002 Section 56.15002 Mineral...MINES Personal Protection § 56.15002 Hard hats. All persons shall wear suitable hard hats when in or around a mine or plant where...

  12. 30 CFR 56.15002 - Hard hats.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 2010-07-01 false Hard hats. 56.15002 Section 56.15002 Mineral...MINES Personal Protection § 56.15002 Hard hats. All persons shall wear suitable hard hats when in or around a mine or plant where...

  13. 30 CFR 56.15002 - Hard hats.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 false Hard hats. 56.15002 Section 56.15002 Mineral...MINES Personal Protection § 56.15002 Hard hats. All persons shall wear suitable hard hats when in or around a mine or plant where...

  14. 30 CFR 56.15002 - Hard hats.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false Hard hats. 56.15002 Section 56.15002 Mineral...MINES Personal Protection § 56.15002 Hard hats. All persons shall wear suitable hard hats when in or around a mine or plant where...

  15. 30 CFR 57.15002 - Hard hats.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 2011-07-01 false Hard hats. 57.15002 Section 57.15002 Mineral...Surface and Underground § 57.15002 Hard hats. All persons shall wear suitable hard hats when in or around a mine or plant where...

  16. Decreased ventilatory function in hard metal workers

    Microsoft Academic Search

    Y Kusaka; M Iki; S Kumagai; S Goto

    1996-01-01

    OBJECTIVES: To study individual effects on pulmonary function of exposure to hard metal including cobalt. METHODS: All of the workers in a hard metal company (583 men and 120 women) were examined for smoking, respiratory symptoms, ventilatory function, occupational history of exposure to hard metal, and present exposure to airborne cobalt. The ventilatory function indices (forced vital capacity (FVC), forced

  17. Model of hard spheroplatelets near a hard wall

    E-print Network

    A. Kapanowski; M. Abram

    2014-06-16

    A system of hard spheroplatelets near an impenetrable wall is studied in the low-density Onsager approximation. Spheroplatelets have optimal shape between rods and plates, and the direct transition from the isotropic to biaxial nematic phase is present. A simple local approximation for the one-particle distribution function is used. Analytical results for the surface tension and the entropy contributions are derived. The density and the order-parameter profiles near the wall are calculated. The preferred orientation of the short molecule axes is perpendicular to the wall. Biaxiality close to the wall can appear only if the phase is biaxial in the bulk.

  18. Hard\\/soft-acid\\/base principle and the reaction AhBs+AsBh-->AhBh+AsBs

    Microsoft Academic Search

    Jerry Goodisman

    2007-01-01

    A demonstration of the hard\\/soft-acid\\/base principle involves showing that the energy change for AhBs+AsBh-->AhBh+AsBs is always negative. We point out problems with assumptions made about hardness and strength of the components, but emphasize that problems with the way in which energies are calculated are even more important.

  19. Hard Questions 1 When Hard Questions are Asked: Evaluating Writing Centers

    E-print Network

    Northern British Columbia, University of

    Hard Questions 1 When Hard Questions are Asked: Evaluating Writing Centers James H. Bell University of Northern British Columbia 3333 University Way Prince George, BC Canada V2N 4Z9 RUNNING HEAD: Hard Questions Reading and Learning. Thank you to three reviewers for their revision suggestions. #12;Hard Questions 2

  20. Hardness Standardization Our objective is to standardize and improve hardness measurement

    E-print Network

    Hardness Standardization METALS Our objective is to standardize and improve hardness measurement both in the U.S. and internationally. NIST is the U.S. National Metrology Institute (NMI) for hardness, and as such, is responsible for traceability in hardness measurements. Objective Impact and Customers