Sample records for radiation hard components

  1. 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.

  2. Impact of aging on radiation hardness

    SciTech Connect

    Shaneyfelt, M.R.; Winokur, P.S.; Fleetwood, D.M. [and others

    1997-07-01

    Burn-in effects are used to demonstrate the potential impact of thermally activated aging effects on functional and parametric radiation hardness. These results have implications on hardness assurance testing. Techniques for characterizing aging effects are proposed.

  3. Radiation hardness studies of CVD diamond detectors

    Microsoft Academic Search

    C. Bauer; I. Baumann; C. Colledani; J. Conway; P. Delpierre; F. Djama; W. Dulinski; A. Fallou; K. K. Gan; R. S. Gilmore; E. Grigoriev; G. Hallewell; S. Han; T. Hessing; K. Honschied; J. Hrubec; D. Husson; H. Kagan; D. Kania; R. Kass; W. Kinnison; K. T. Knöpfle; M. Krammer; T. J. Llewellyn; P. F. Manfredi; L. S. Pan; H. Pernegger; M. Pernicka; R. Plano; V. Re; S. Roe; A. Rudge; M. Schaeffer; S. Schnetzer; S. Somalwar; V. Speziali; R. Stone; R. J. Tapper; R. Tesarek; W. Trischuk; R. Turchetta; G. B. Thomson; R. Wagner; P. Weilhammer; C. White; H. Ziock; M. Zoeller

    1995-01-01

    The inherent properties of diamond make it an ideal material for tracking detectors especially in the high rate, high radiation environments of future colliders such as the LHC. In order to survive in this environment, detectors must be radiation hard. We have constructed charged particle detectors using high quality CVD diamond and performed radiation hardness tests on them. The signal

  4. 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.

  5. 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.

  6. 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.

  7. Implementing QML for radiation hardness assurance

    SciTech Connect

    Winokur, P.S.; Sexton, F.W.; Fleetwood, D.M.; Terry, M.D.; Shaneyfelt, M.R.; Dressendorfer, P.V.; Schwank, J.R. (Sandia National Labs., Albuquerque, NM (USA))

    1990-12-01

    Statistical process control (SPC) of technology parameters relevant to radiation hardness, test structure to IC correlation, and extrapolation from laboratory to threat scenarios are keys to implementing QML for radiation hardness assurance {ital in a cost-effective manner}. Data from approximately 300 wafer lots fabricated in a 4/3-{mu}m and CMOS IIIA (2-{mu}m) technologies are used to demonstrate approaches to, and highlight issues associated with, implementing QML for radiation-hardened CMOS in space applications. An approach is demonstrated to implement QML for single-event upset (SEU) immunity on 16 k SRAMs that involves relating values of feedback resistance to system error rates.

  8. 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.

  9. Radiation hard cryogenic silicon detectors

    Microsoft Academic Search

    L. Casagrande; M. C. Abreu; W. H. Bell; P. Berglund; W. de Boer; E. Borchi; K. Borer; M. Bruzzi; S. Buontempo; S. Chapuy; V. Cindro; P. Collins; N. D'Ambrosio; C. Da Viá; S. Devine; B. Dezillie; Z. Dimcovski; V. Eremin; A. Esposito; V. Granata; E. Grigoriev; F. Hauler; E. Heijne; S. Heising; S. Janos; L. Jungermann; I. Konorov; Z. Li; C. Lourenço; M. Mikuz; T. O. Niinikoski; V. O'Shea; S. Pagano; V. G. Palmieuri; S. Paul; S. Pirollo; K. Pretzl; P. Rato; G. Ruggiero; K. Smith; P. Sonderegger; P. Sousa; E. Verbitskaya; S. Watts; M. Zavrtanik

    2002-01-01

    It has been recently observed that heavily irradiated silicon detectors, no longer functional at room temperature, “resuscitate” when operated at temperatures below 130K. This is often referred to as the “Lazarus effect”. The results presented here show that cryogenic operation represents a new and reliable solution to the problem of radiation tolerance of silicon detectors.

  10. Implementing QML for radiation hardness assurance

    Microsoft Academic Search

    P. S. Winokur; F. W. Sexton; D. M. Fleetwood; M. D. Terry; M. R. Shaneyfelt

    1990-01-01

    The US government has proposed a qualified manufacturers list (QML) methodology to qualify integrated circuits for high reliability and radiation hardness. An approach to implementing QML for single-event upset (SEU) immunity on 16k SRAMs that involves relating values of feedback resistance to system error rates is demonstrated. It is seen that the process capability indices, Cp and Cpk, for the

  11. Implementing QML for radiation hardness assurance

    Microsoft Academic Search

    P. S. Winokur; F. W. Sexton; D. M. Fleetwood; M. D. Terry; M. R. Shaneyfelt; P. V. Dressendorfer; J. R. Schwank

    1990-01-01

    The US government has proposed a qualified manufacturers list (QML) methodology to qualify integrated circuits for high reliability and radiation hardness. An approach to implementing QML for single-event upset (SEU) immunity on 16k SRAMs that involves relating values of feedback resistance to system error rates is demonstrated. It is seen that the process capability indices, Cp and C pk, for

  12. Improved radiation hardness of silicon solar cells

    Microsoft Academic Search

    Hidetoshi Washio; Yoshifumi Tonomura; Minoru Kaneiwa; Tatsuo Saga; O. Anzawa; S. Matsuda

    2000-01-01

    SHARP and NASDA (National Space Development Agency of Japan) have been engaged in the development of silicon space solar cells since 1970s. We started the project to improve the radiation hardness of silicon solar cells in 1998. This project gave fruitful results in BJ (both-side junction) and AHES (advanced high efficiency silicon) structure. The design and manufacturing process for the

  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. 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.

  16. Radiation hardness assurance of space electronics

    Microsoft Academic Search

    Leonard Adams; Andrew Holmes-Siedle

    1992-01-01

    Space radiation causes significant damage to electronic components and the performance of any spacecraft is governed by the performance of the various electronic systems such as scientific instruments, data handling and communications. Instruments for space research employ highly complex electronics and there is an increasing emphasis on imaging instruments which require large amounts of memory and powerful advanced data processing.

  17. 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.

  18. 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.

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

    E-print Network

    Lutomirski, Andrew

    2011-01-01

    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.

  20. Radiation hardness of lead glasses TF1 and TF101

    NASA Astrophysics Data System (ADS)

    Kobayashi, Masaaki; Prokoshkin, Yuri; Singovsky, Alexandre; Takamatsu, Kunio

    1994-06-01

    We have measured the radiation hardness of two types of lead glasses, TF1 and TF101, for low energy ?-rays from 60Co. TF101 containing cerium is a few tens times radiation harder than TF1 which contains no cerium. The radiation hardness, or the tolerable accumulated dose, of TF101 is 2 × 10 3 rad when the degradation of the transmittance is required to be less than 1% for the unit radiation length X0 = 2.8 cm. When the present result is compared with the work of Inyakin et al., the radiation hardness of TF101 glass should be similar for both ?-rays and for high energy hadrons.

  1. 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.

  2. 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.

  3. 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.

  4. Implementing QML (Qualified Manufacturers List) for radiation hardness assurance

    Microsoft Academic Search

    P. S. Winokur; F. W. Sexton; D. M. Fleetwood; M. D. Terry; M. R. Shaneyfelt; P. V. Dressendorfer; J. R. Schwank

    1990-01-01

    Statistical process control (SPC) of technology parameters relevant to radiation hardness, test structure to Integrated Circuit (IC) correlation, and extrapolation from laboratory to threat scenarios are keys to implementing Qualified Manufacture's List (QML) for radiation hardness assurance in a cost-effective manner. Data from approximately 300 wafer lots fabricated in Sandia's 4\\/3-μm and Complementry Metal Oxide Semiconductor (CMOS) IIIA (2-μm) technologies

  5. GaN as a radiation hard particle detector

    Microsoft Academic Search

    J. Grant; R. Bates; W. Cunningham; A. Blue; J. Melone; F. McEwan; J. Vaitkus; E. Gaubas; V. O’Shea

    2007-01-01

    Semiconductor tracking detectors at experiments such as ATLAS and LHCb at the CERN Large Hadron Collider (LHC) will be subjected to intense levels of radiation. The proposed machine upgrade, the Super-LHC (SLHC), to 10 times the initial luminosity of the LHC will require detectors that are ultra-radiation hard. Much of the current research into finding a detector that will meet

  6. 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.

  7. Wafer-level radiation testing for hardness assurance

    Microsoft Academic Search

    M. R. Shaneyfelt; K. L. Hughes; J. R. Schwank; F. W. Sexton; D. M. Fleetwood; P. S. Winokur; E. W. Enlow

    1991-01-01

    To implement the qualified manufacturers list (QML) approach to hardness assurance in a practical and cost-effective manner, one must identify technology parameters that affect radiation hardness and bring them under statistical process control. To aid this effort, the authors have developed a wafer-level test system to map test-structure and IC response across a wafer. This system permits current-voltage and charge-pumping

  8. Conceptual Design of and Radiation Hardness

    E-print Network

    McDonald, Kirk

    Optimization #12;Magnet Design target station experimental hall proton beam Concrete CryostatCryostat--11 Yoke #12;Radiation on CS 7.9W2.0W1.0W0.7W 0.9W1.4W Neutron flux (n/cm2/proton) Maximum heat deposit 10

  9. Total-dose radiation hardness assurance for space electronics

    Microsoft Academic Search

    Peter S. Winokur; Daniel M. Fleetwood

    1991-01-01

    An improved standard total-dose test method is described to qualify electronics for a low-dose radiation environment typical of space systems. The method consists of Co-60 irradiation at a dose rate of 1 to 3 Gy(Si)\\/s (100 to 300 rad(Si)\\/s) and a subsequent 373 K (100 C) bake. New initiatives in radiation hardness assurance are also briefly discussed, including the Qualified

  10. Total-dose radiation hardness assurance for space electronics

    Microsoft Academic Search

    Peter S. Winokur; Daniel M. Fleetwood

    1991-01-01

    An improved standard total-dose test method is described to qualify electronics for a low-dose-rate radiation environment typical of space systems. The method consists of 60Co irradiation at a dose rate of 1-3 Gy(Si)\\/s (100-300 rad(Si)\\/s) and a subsequent 373 K (100 °C) bake. New initatives in radiation hardness assurance are also briefly discussed, including the Qualified Manufactures List (QML) test

  11. Total-dose radiation hardness assurance for space electronics

    Microsoft Academic Search

    Peter S. Winokur; Daniel M. Fleetwood

    1991-01-01

    An improved standard total-dose test method is described to qualify electronics for a low-dose-rate radiation environment typical of space systems. The method consists of 60Co irradiation at a dose rate of 1–3 Gy(Si)\\/s (100–300 rad(Si)\\/s) and a subsequent 373 K (100 °C) bake. New initatives in radiation hardness assurance are also briefly discussed, including the Qualified Manufactures List (QML) test

  12. Total-dose radiation hardness assurance for space electronics

    Microsoft Academic Search

    Peter S. Winokur; Daniel M. Fleetwood

    1990-01-01

    An improved standard total-dose test method is described to qualify electronics for a low-dose radiation environment typical of space systems. The method consists of Co-60 irradiation at a dose rate of 1 to 3 Gy(Si)\\/s (100 to 300 rad(Si)\\/s) and a subsequent 373 K (100 C) bake. New initiatives in radiation hardness assurance are also briefly discussed, including the Qualified

  13. Cryogenic Si detectors for ultra radiation hardness in SLHC environment

    Microsoft Academic Search

    Zheng Li; M. Abreu; P. Anbinderis; T. Anbinderis; N. D’. Ambrosio; W. de Boer; E. Borchi; K. Borer; M. Bruzzi; S. Buontempo; W. Chen; V. Cindro; A. Dierlamm; V. Eremin; E. Gaubas; V. Gorbatenko; E. Grigoriev; F. Hauler; E. Heijne; S. Heising; O. Hempel; R. Herzog; J. Härkönen; I. Ilyashenko; S. Janos; L. Jungermann; V. Kalesinskas; J. Kapturauskas; R. Laiho; P. Luukka; I. Mandic; Rita De Masi; D. Menichelli; M. Mikuz; O. Militaru; T. O. Niinikosky; V. O’. Shea; S. Pagano; S. Paul; K. Piotrzkowski; K. Pretzl; P. Rato Mendes; X. Rouby; G. Ruggiero; K. Smith; P. Sonderegger; P. Sousa; E. Tuominen; E. Tuovinen; E. Verbitskaya; J. Vaitkus; E. Wobst; M. Zavrtanik

    2007-01-01

    Radiation hardness up to 1016neq\\/cm2 is required in the future HEP experiments for most inner detectors. However, 1016neq\\/cm2 fluence is well beyond the radiation tolerance of even the most advanced semiconductor detectors fabricated by commonly adopted technologies: the carrier trapping will limit the charge collection depth to an effective range of 20–30?m regardless of depletion depth. Significant improvement of the

  14. Investigation of Radiation Hardness of Germanium Photovoltaic Cells

    Microsoft Academic Search

    Raymond Hoheisel; Jara Fernandez; Frank Dimroth; Andreas W. Bett

    2010-01-01

    This contribution discusses the radiation hardness of germanium (Ge) photovoltaic cells under space conditions corresponding to an irradiation dose of 1-MeV 1 × 1015 cm-2 electrons. For this purpose, different germanium photovoltaic cell technologies based on p-type substrates are analyzed. The investigation comprises standard Ge photovoltaic cells with a substrate doping concentration of NA = 1 × 1017 cm-3, as

  15. Solar cell nanotechnology for improved efficiency and radiation hardness

    Microsoft Academic Search

    Alexander I. Fedoseyev; Marek Turowski; Qinghui Shao; Alexander A. Balandin

    2006-01-01

    Space electronic equipment, and NASA future exploration missions in particular, require improvements in solar cell efficiency and radiation hardness. Novel nano-engineered materials and quantum-dot array based photovoltaic devices promise to deliver more efficient, lightweight solar cells and arrays which will be of high value to long term space missions. In this paper, we describe issues related to the development of

  16. 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.

  17. Radiation-Hard ASICs for LHC Optical Data Transmission

    E-print Network

    Gan, K. K.

    Radiation-Hard ASICs for LHC Optical Data Transmission K.K. Gan, H.P. Kagan, R.D. Kass, J.R. Moore, D.S. Smith Abstract­We have designed three ASICs for possible applications in the optical links luminosity upgrade. The ASICs include a high-speed driver for the VCSEL, a receiver/decoder to decode

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

    NASA Astrophysics Data System (ADS)

    Rasouli, C.; Pourshahab, B.; Hosseini Pooya, S. M.; Orouji, T.; Rasouli, H.

    2014-05-01

    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.

  19. 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.

  20. Radiation-hard silicon for LH-LHC trackers

    NASA Astrophysics Data System (ADS)

    Soldevila, U.

    2011-12-01

    In order to harvest the maximum physics potential of the CERN Large Hadron Collider (LHC), it is foreseen to significantly increase the LHC luminosity by upgrading the LHC towards the HL-LHC (High Luminosity LHC), also known as sLHC. The final upgrade (Phase-II) will mean unprecedented radiation levels, exceeding the LHC fluences by roughly an order of magnitude. Due to the radiation damage limitations of the silicon sensors presently used, the physics experiments will require new tracking detectors for HL-LHC operation. All-silicon central trackers are being studied in ATLAS, CMS and LHCb, with extremely radiation hard silicon sensors to be employed on the innermost layers. Within the CERN RD50 Collaboration, a massive R&D programme is underway across experimental boundaries to develop silicon sensors with sufficient radiation tolerance. We will present results of several detector technologies and silicon materials at radiation levels corresponding to HL-LHC fluences.

  1. A Radiation Hard Lut Block with Auto-Scrubbing

    Microsoft Academic Search

    Kashfia Haque; Paul Beckett

    2011-01-01

    We present a Silicon-on-Insulator based Look-up Table and configuration memory for application within a radiation hard reconfigurable system. The configuration storage includes a non-volatile EEPROM built using a standard single polysilicon Silicon on Insulator CMOS process linked to a Schmitt sense amplifier and transmission gate LUT structure. A simple current detector of the type used in conventional RAM circuits allows

  2. Performance of radiation hard CCDs as tracking devices

    NASA Astrophysics Data System (ADS)

    Bross, Alan D.; Clegg, Derek B.

    1986-06-01

    We present data on the operation of radiation hard CCDs used as tracking devices. The system consisted of 5 Texas Instruments CCDs with a total number of cells equal to 2.7 × 10 6. The tracking resolution for minimum ionizing particles was measured to be ?x = 4.8 ± 0.2 ?m and ?y = 5.0 ± 0.3 ?m. Two track separation of better than 40 ?m in space was also obtained.

  3. Total-dose radiation hardness assurance for space electronics

    SciTech Connect

    Winokur, P.S.; Fleetwood, D.M.

    1990-01-01

    An improved standard total-dose test method is described to qualify electronics for a low-dose radiation environment typical of space systems. The method consists of {sup 60}Co irradiation at a dose rate of 1--3 Gy(Si)/s (100--300 rad(Si)/s) and a subsequent 373 K (100{degree}C) bake. New initiatives in radiation hardness assurance are also briefly discussed, including the Qualified Manufacturers List (QML) test methodology and the possible use of 1/f noise measurements as a nondestructive screen for oxide-trap charge related failure. 8 refs.

  4. 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.

  5. Radiation-resistant beamline components at LAMPF

    SciTech Connect

    Macek, R.J.; Grisham, D.L.; Lambert, J.e.; Werbeck, R.

    1983-01-01

    A variety of highly radiation-resistant beamline components have been successfully developed at LAMPF primarily for use in the target cells and beam stop area of the intense proton beamline. Design features and operating experience are reviewed for magnets, instrumentation, targets, vacuum seals, vacuum windows, collimators, and beam stops.

  6. Application of hardness-by-design methodology to radiation-tolerant ASIC technologies

    Microsoft Academic Search

    Ronald C. Lacoe; Jon V. Osborn; Rocky Koga; Stephanie Brown; Donald C. Mayer

    2000-01-01

    Radiation-hard ASIC design is enabled by the trend in commercial microelectronics toward increased radiation hardness, demonstrated here with new radiation results on a 0.25-?m commercial process utilizing shallow trench isolation. A design comparison is made between creating ASICs targeting a traditional rad-hard foundry, which may be more than two generations behind commercial foundries, applying hardness-by-design methodology at a commercial foundry,

  7. Radiation hardness of three-dimensional polycrystalline diamond detectors

    NASA Astrophysics Data System (ADS)

    Lagomarsino, Stefano; Bellini, Marco; Corsi, Chiara; Cindro, Vladimir; Kanxheri, Keida; Morozzi, Arianna; Passeri, Daniele; Servoli, Leonello; Schmidt, Christian J.; Sciortino, Silvio

    2015-05-01

    The three-dimensional concept in particle detection is based on the fabrication of columnar electrodes perpendicular to the surface of a solid state radiation sensor. It permits to improve the radiation resistance characteristics of a material by lowering the necessary bias voltage and shortening the charge carrier path inside the material. If applied to a long-recognized exceptionally radiation-hard material like diamond, this concept promises to pave the way to the realization of detectors of unprecedented performances. We fabricated conventional and three-dimensional polycrystalline diamond detectors, and tested them before and after neutron damage up to 1.2 ×1016 cm-2, 1 MeV-equivalent neutron fluence. We found that the signal collected by the three-dimensional detectors is up to three times higher than that of the conventional planar ones, at the highest neutron damage ever experimented.

  8. 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.

  9. 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.

  10. Efficiency and radiation hardness of phosphors in a proton beam

    NASA Astrophysics Data System (ADS)

    Holland, L. R.; Jenkins, G. M.; Fisher, J. H.; Hollerman, W. A.; Shelby, G. A.

    1991-05-01

    A new system has been used to measure the relative peak efficiency and radiation damage endurance of several phosphor-binder combinations on aluminum substrates. The phosphors tested are Gd 2O 2S doped with Pr, Tb, and Eu; Y 2O 2S doped with Tb and Eu; YAG doped with Ce; and ZnS doped with Ag. The binders used are a polysiloxane resin and sodium silicate. Binder with suspended phosphor was sprayed on the heated substrates. Tests were done on a 3 MeV proton beam at the University of Lowell Van de Graaff accelerator. The aluminum substrates are formed as rotatable turrets to facilitate sample changes. Light measurement was by means of a silicon photodiode with no optical filter except a glass window. Ce doped YAG shows the best radiation hardness, while Y 2O 2S doped with Eu shows the highest fluorescence efficiency.

  11. Hydrogenated Amorphous Silicon Radiation Detectors: Material Parameters; Radiation Hardness; Charge Collection

    NASA Astrophysics Data System (ADS)

    Qureshi, Shafi

    Properties of hydrogenated amorphous silicon p -i-n diodes relevant to radiation detection applications were studied. The interest in using this material for radiation detection applications in physics and medicine was motivated by its high radiation hardness and the fact that it can be deposited over large area at relatively low cost. Thick, fully depleted a-Si:H diodes are required for sufficient energy deposition by a charged particle and better signal to noise ratio. A sizeable electric field is essential for charge collection in a-Si:H diodes. The large density of ionized defects that exist in the i layer when the diode is under DC bias causes the electric field to be nonuniform. Material parameters, namely carrier mobility and lifetime and the ionized defect density in thick a-Si:H p-i-n diodes (quantities that affect field shape and charge collection) were studied by the transient photoconductivity method. The ionized defect density thus measured was found to be ~1/3 of the total defect density measured by ESR. The increase in diode leakage current with reverse bias over the operating bias was consistent with the Poole -Frenkel effect, involving excitation of carriers from neutral defects. The diode noise over the operating voltage range was completely explained in terms of the shot noise component for CR-(RC)^4 (pseudo-Gaussian) shaping at 3 mus shaping time and the noise component at 0 V bias (delta and thermal noise) added in quadrature. Irradiation with 1 Mev neutrons produced no significant degradation in leakage current and noise at fluences exceeding 4 times 10 ^{14} cm^ {-2}. Irradiation with 1.4 Mev proton fluence of 1 times 10^ {14} cm^{-2} decreased carrier lifetime by a factor of ~4. Degradation in leakage current and noise became significant at proton fluence of ~10^{13} cm^{-2}. Detected radiation signals had timing and size consistent with measured mobility and lifetime. Significant charge collection was observed in a 31 mu m a-Si:H diode from a minimum ionizing particle (beta particles from Sr-90 source) at shaping times as low as 20 ns. This was also corroborated by measurements with 860 Mev alpha particles at short shaping times. At 100 ns shaping time most of the electrons were collected with only a small contribution to the signal from the hole collection. Further, the charge collection did not change appreciably when shaping time was increased to as long as 3 mus. These measurements suggested that in thicker a-Si:H diodes electron collection alone could produce large enough signals, making a faster a-Si:H device more realistic.

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

    E-print Network

    Zavrtanik, Marko

    2002-01-01

    Nuclear Instruments and Methods in Physics Research A 477 (2002) 299­303 Radiation hard cryogenic 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 been

  13. Implementing QML (Qualified Manufacturers List) for radiation hardness assurance

    SciTech Connect

    Winokur, P.S.; Sexton, F.W.; Fleetwood, D.M.; Terry, M.D.; Shaneyfelt, M.R.; Dressendorfer, P.V.; Schwank, J.R.

    1990-01-01

    Statistical process control (SPC) of technology parameters relevant to radiation hardness, test structure to Integrated Circuit (IC) correlation, and extrapolation from laboratory to threat scenarios are keys to implementing Qualified Manufacture's List (QML) for radiation hardness assurance in a cost-effective manner. Data from approximately 300 wafer lots fabricated in Sandia's 4/3-{mu}m and Complementry Metal Oxide Semiconductor (CMOS) IIIA (2-{mu}m) technologies are used to demonstrate approaches to, and highlight issues associated with, implementing QML for radiation-hardened CMOS in space applications. An approach is demonstrated to implement QML for signal-event upset SEU immunity on 16k SRAMs that involves relating values of feedback resistance to system error rates. It is seen that the process capability indices, C{sub p} and C{sub pk}, for the manufacture of 400 k{Omega} feedback resistors required to provide SEU tolerance do not conform to 6{sigma}'' quality standards. For total-dose, {triangle}V{sub it} shifts measured on transistors are correlated with circuit response in the space environment. SPC is illustrated for {triangle}V{sub it}, and violations of SPC rules are interpreted in terms of continuous improvement. Finally, design validation for SEU, and quality conformance inspections for total-dose, are identified as major obstacles to cost-effective QML implementation. Techniques and tools that will help QML provide real cost savings are identified as physical models, three-dimensional device-plus-circuit codes, and improved design simulators. 29 refs., 10 figs., 1 tab.

  14. 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.

  15. 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

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

    Microsoft Academic Search

    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

    2009-01-01

    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

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

    Microsoft Academic Search

    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

    2010-01-01

    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

  18. Design of radiation hard CMOS APS image sensors for space applications

    Microsoft Academic Search

    E. El-Sayed

    2000-01-01

    The overall objective the research work described in this paper was to design a radiation hard CMOS active pixel sensor (APS), which is intended for use in imaging systems flown on future NASA space missions in the era of ever decreasing mass and power budgets. The radiation hard designs of essential circuits required to enable the design of an experimental

  19. The diffuse component of the cosmic X-radiation

    NASA Technical Reports Server (NTRS)

    Boldt, E. A.; Garmire, C.

    1978-01-01

    The A-2 experiment on HEAO-1 is specifically developed to study the diffuse radiation of the entire X-ray sky over a wide bandwidth, covering both the soft X-ray emission from nearby regions of the galaxy and the isotropic hard X-radiation indicative of remote extragalactic origins. A partial conclusion from the experiment is that a hot thermal plasma, on a scale comparable to that of the universe, may be the principal source of hard X-radiation characteristic of the extragalactic sky. Some key features of this background were defined.

  20. Experimental and Numerical Study of Shot Peened Thin Hard-Coated Components

    Microsoft Academic Search

    S. Baragetti; F. Tordini

    2011-01-01

    A test bench was designed and assembled to carry out impact tests on samples and components. The system allows simple and rapid adjustment of the test parameters, such as the shot size and air pressure, with good repeatability of the results. Tests on steel and light alloys were carried out under both as-produced condition and on thin hard-coated samples. Significant

  1. 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.

  2. Radiation-hard/high-speed parallel optical engine

    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.

    2012-12-01

    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 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. We have received 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. Some preliminary results of the design will be presented.

  3. 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.

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

    SciTech Connect

    Summers, G.P.; Walters, R.J.; Messenger, S.R.; Burke, E.A. [SFA, Inc., Landover, MD (United States); [Burke, Edward A., Woburn, MA (United States)

    1995-10-01

    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 costs.

  5. RADIATION-HARD ASICS FOR OPTICAL DATA TRANSMISSION IN THE ATLAS PIXEL DETECTOR

    E-print Network

    Gan, K. K.

    RADIATION-HARD ASICS FOR OPTICAL DATA TRANSMISSION IN THE ATLAS PIXEL DETECTOR K.K. GAN, K.E. ARMS-hard ASICs for optical data transmission in the ATLAS pixel detector at the LHC at CERN: a driver chip diode. We have successfully implemented both ASICs in 0.25 mm CMOS technology using enclosed layout

  6. Experiences with shape memory alloy: robot grippers for submillimeter hard disk drive components

    Microsoft Academic Search

    Mark H. MacKenzie; Naomi M. An; Matthew D. Giere; James A. Stori; Paul Wright

    1996-01-01

    Grippers for an automated assembly cell are being developed for handling individual sub-millimeter hard-disc drive components. Processing requirements dictate positive gripping with a strong actuator that meets clean room specifications. Proof-of-concept testing of shape memory alloy (SMA) as an actuator was performed. The response time of Ni-Ti 0.076 mm diameter shape memory wire was found to be 0.15 seconds under

  7. Estimation of surface longwave radiation components from ground-based historical net radiation and weather data

    Microsoft Academic Search

    Gi-Hyeon Park; Xiaogang Gao; Soroosh Sorooshian

    2008-01-01

    A methodology for estimating ground upwelling, clear-sky and cloud downwelling longwave radiations (L ?, L sky ?, and L cld ?) and net shortwave radiation (S n ) at 30-min temporal scales based on long-term ground-based net radiations and meteorological observations is described. Components of surface radiation can be estimated from empirical models, cloud radiation models, and remote sensing observations.

  8. 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.

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

    Microsoft Academic Search

    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

    2010-01-01

    Ensuring the radiation hardness of PbWO4 crystals was one of the main\\u000apriorities during the construction of the electromagnetic calorimeter of the\\u000aCMS experiment at CERN. The production on an industrial scale of radiation hard\\u000acrystals and their certification over a period of several years represented a\\u000adifficult challenge both for CMS and for the crystal suppliers. The present\\u000aarticle

  10. Comparison of the radiation hardness of various VLSI technologies for defense applications

    SciTech Connect

    Gibbon, C.F.

    1985-01-01

    In this review the radiation hardness of various potential very large scale (VLSI) IC technologies is evaluated. IC scaling produces several countervailing trends. Reducing vertical dimensions tends to increase total dose hardness, while reducing lateral feature sizes may increase susceptibility to transient radiation effects. It is concluded that during the next decade at least, silicon complimentary MOS (CMOS), perhaps on an insulating substrate (SOI) will be the technology of choice for VLSI in defense systems.

  11. Radiation hardness of SiC based ions detectors for influence of the relative protons

    Microsoft Academic Search

    A. M Ivanov; N. B Strokan; D. V Davydov; N. S Savkina; A. A Lebedev; Yu. T Mironov; G. A Riabov; E. M Ivanov

    2001-01-01

    Nuclear detector radiation hardness is very important for key experiments in high-energy physics, where the irradiation fluence of relativistic particles can be as high as 1015cm?2. In this work, we investigate the radiation hardness of SiC Schottky diode detectors ?600?m, obtained by magnetron sputtering of Ni on surface of 6H–SiC films, grown by sublimation epitaxy in vacuum. Irradiation has been

  12. Hardness measurements of silicone rubber and polyurethane rubber cured by ionizing radiation

    NASA Astrophysics Data System (ADS)

    Basfar, Ahmed Ali

    1997-12-01

    This work investigates the hardness of both silicone rubber and polyurethane rubber cured by ionizing radiation. Shore A hardness is used to characterize the subject elastomers in relation to the crosslinking process. Various formulations of both materials have been investigated in order to achieve the optimum cure conditions. A small amount of a chemical curing agent has been incorporated in some formulations in order to reduce the required dose to achieve full cure conditions. Silicone rubber improved in hardness with increasing absorbed dose, whereas hardness remained constant over a broad range of absorbed doses for polyurethane rubber.

  13. Radiation hardness of fluorinated oxides prepared by liquid phase deposition method following rapid thermal oxidation

    Microsoft Academic Search

    Wei-Shin Lu; Jenq-Shiuh Chou; Si-Chen Lee; Jenn-Gwo Hwu

    1994-01-01

    Liquid phase deposition (LPD following rapid thermal oxidation 2 RTO) is proposed as a method to obtain the fluorinated gate oxides. The radiation effect on these fluorinated oxides prepared by various sequences is studied. It was experimentally observed that all the fluorinated gate oxides are more radiation hard than the rapid thermal oxide (control oxide). Interestingly, the amount of fluorine

  14. Maximally Random Jamming of Two-Dimensional One-Component and Binary Hard Disc Fluids

    E-print Network

    Xinliang Xu; Stuart A. Rice

    2010-10-05

    We report calculations of the density of maximally random jamming (aka random close packing) of one-component and binary hard disc fluids. The theoretical structure used provides a common framework for description of the hard disc liquid to hexatic, the liquid to hexagonal crystal and the liquid-to-maximally random jammed state transitions. Our analysis is based on locating a particular bifurcation of the solutions of the integral equation for the inhomogeneous single particle density at the transition between different spatial structures. The bifurcation of solutions we study is initiated from the dense metastable fluid, and we associate it with the limit of stability of the fluid, which we identify with the transition from the metastable fluid to a maximally random jammed state. For the one-component hard disc fluid the predicted packing fraction at which the metastable fluid to maximally random jammed state transition occurs is 0.84, in excellent agreement with the experimental value 0.84 \\pm 0.02. The corresponding analysis of the limit of stability of a binary hard disc fluid with specified disc diameter ratio and disc composition requires extra approximations in the representations of the direct correlation function, the equation of state, and the number of order parameters accounted for. Keeping only the order parameter identified with the largest peak in the structure factor of the highest density regular lattice with the same disc diameter ratio and disc composition as the binary fluid, the predicted density of maximally random jamming is found to be 0.84 to 0.87, depending on the equation of state used, and very weakly dependent on the ratio of disc diameters and the fluid composition, in agreement with both experimental data and computer simulation data.

  15. The effect of heavy metal contamination in SIMOX on radiation hardness of MOS transistors

    NASA Astrophysics Data System (ADS)

    Ipri, Alfred C.; Jastrzebski, L.; Peters, D.

    1989-12-01

    It is shown that heavy-metal contamination introduced during implantation of oxygen into silicon results in a reduction of SIMOX (separation by implanted oxygen) oxide radiation hardness. Radiation-induced back-channel leakage currents in MOS transistors processed in SIMOX films containing various levels of heavy metals, as measured by surface photovoltage (SPV), are a strong function of heavy metal concentration. It is concluded that SPV measurements of as-implanted SIMOX wafers can be used as a rapid nondestructive quality control inspection technique to predict the radiation hardness of the SIMOX oxide prior to processing.

  16. 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

  17. Experimental study of hard photon radiation processes at HERA

    Microsoft Academic Search

    T. Ahmed; S. Aid; V. Andreev; B. Andrieu; R.-D. Appuhn; M. Arpagaus; A. Babaev; J. Baehr; J. Bán; P. Baranov; E. Barrelet; W. Bartel; M. Barth; U. Bassler; H. Bergstein; H.-J. Behrend; A. Belousov; Ch. Berger; G H Bertrand-Coremans; R. Bernet; M. Besançon; R. Beyer; P. Biddulph; J. C. Bizot; V. Blobel; K. Borras; F. Botterweck; V. Boudry; A. Braemer; F. Brasse; W. Braunschweig; V. Brisson; D. Bruncko; C. Brune; R. Buchholz; L. Büngener; J. Bürger; F. W. Büsser; A. Buniatian; S. Burke; G. Buschhorn; A. J. Campbell; T. Carli; F. Charles; D. Clarke; A. B. Clegg; B. Clerbaux; M. Colombo; J. G. Contreras; C. Cormack; J. A. Coughlan; A. Courau; Ch. Coutures; G. Cozzika; L. Criegee; D. G. Cussans; J. Cvach; S. Dagoret; J. B. Dainton; M. Danilov; W. D. Dau; K. Daum; M. David; E. Deffur; B. Delcourt; L. Del Buono; A. De Roeck; E. A. De Wolf; P. Di Nezza; C. Dollfus; John D Dowell; H. B. Dreis; A. Droutskoi; J. Duboc; D. Düllmann; O. Dünger; H. Duhm; J. Ebert; T. R. Ebert; G. Eckerlin; V. Efremenko; S. Egli; H. Ehrlichmann; S. Eichenberger; R. Eichler; F. Eisele; E. Eisenhandler; R. J. Ellison; E. Elsen; M. Erdmann; W. Erdmann; E. Evrard; L. Favart; A. Fedotov; D. Feeken; R. Felst; Joel Feltesse; J. Ferencei; F. Ferrarotto; K. Flamm; M. Fleischer; M. Flieser; G. Flügge; A. Fomenko; B A Fominykh; M. Forbush; J. Formánek; J. M. Foster; G. Franke; E. Fretwurst; Erwin Gabathuler; K. Gabathuler; K. Gamerdinger; J. Garvey; J. Gayler; M. Gebauer; A. Gellrich; H. Genzel; R. Gerhards; U. Goerlach; L. Goerlich; N. Gogitidze; M. Goldberg; D. Goldner; B. Gonzalez-Pineiro; I. Gorelov; P. Goritchev; C. Grab; H. Grässler; T. Greenshaw; G. Grindhammer; A. Gruber; C. Gruber; J. Haack; Dieter Haidt; L. Hajduk; O. Hamon; M. Hampel; E. M. Hanlon; M. Hapke; W. J. Haynes; J. Heatherington; G. Heinzelmann; R. C. W. Henderson; H. Henschel; R. Herma; I. Herynek; M. F. Hess; W. Hildesheim; P. Hill; K. H. Hiller; C. D. Hilton; J. Hladký; K. C. Hoeger; M. Höppner; R. Horisberger; V. L. Hudgson; Ph. Huet; H. Hufnagel; M. Ibbotson; H. Itterbeck; M.-A. Jabiol; A. Jacholkowska; C. Jacobsson; M. Jaffre; J. Janoth; T. Jansen; L. Jönsson; K. Johannsen; D. P. Johnson; L. Johnson; H. Jung; Peter I P Kalmus; D. Kant; R. Kaschowitz; P. Kasselmann; U. Kathage; J M Katzy; H. H. Kaufmann; S. Kazarian; Ian Richard Kenyon; S. Kermiche; C. Keuker; C. Kiesling; M. Klein; C. Kleinwort; G. Knies; W. Ko; T. Köhler; J. Köhne; H. Kolanoski; F. Kole; S. D. Kolya; V. Korbel; M. Korn; P. Kostka; S. K. Kotelnikov; T. Krämerkämper; M. W. Krasny; H. Krehbiel; D. Krücker; U. Krüger; U. Krüner-Marquis; J. P. Kubenka; H. Küster; M. Kuhlen; J. Kurzhöfer; B. Kuznik; D. Lacour; F. Lamarche; R. Lander; M. P. J. Landon; W. Lange; P. Lanius; J.-F. Laporte; A. Lebedev; C. Leverenz; S. Levonian; Ch. Ley; A. Lindner; G. Lindström; F. Linsel; J. Lipinski; B. List; P. Loch; H. Lohmander; G. C. Lopez; V. Lubimov; D. Lüke; N. Magnussen; E I Malinovskii; S. Mani; R. Maracek; P. Marage; J. Marks; R. Marshall; J. Martens; R D Martin; H.-U. Martyn; J. Martyniak; S. Masson; T. Mavroidis; S. J. Maxfield; S. J. McMahon; A. Mehta; K. Meier; D. Mercer; T. Merz; C. A. Meyer; H. Meyer; J. Meyer; S. Mikocki; D. Milstead; F. Moreau; J. V. Morris; E. Mroczko; G. Müller; K. Müller; P. Murín; V Nagovitsin; R. Nahnhauer; Beate Naroska; Th. Naumann; P. R. Newman; D. Newton; D. Neyret; H. K. Nguyen; T. C. Nicholls; F. Niebergall; C B Niebuhr; R. Nisius; G. Nowak; G. W. Noyes; M. Nyberg-Werther; M N Oakden; H. Oberlack; U. Obrock; J. E. Olsson; D. Ozerov; E. Panaro; A. Panitch; C. Pascaud; G. D. Patel; E. Peppel; E. Perez; J. P. Phillips; Ch. Pichler; D. Pitzl; G. Pope; S. Prell; R. Prosi; G. Rädel; F. Raupach; P. Reimer; S. Reinshagen; P. Ribarics; H. Rick; V. Riech; J. Riedlberger; S. Riess; M. Rietz; E. Rizvi; S. M. Robertson; P. Robmann; H. E. Roloff; R. Roosen; K. Rosenbauer; A. Rostovtsev; F. Rouse; C. Royon; K Rybicki; S. Rusakov; R. Rylko; N. Sahlmann; E. Sanchez; D. P. C. Sankey; M. Savitsky; P. Schacht; S. Schiek; P. Schleper; W. von Schlippe; C. Schmidt; D. Schmidt; G. Schmidt; A. Schöning; V. Schröder; E. Schuhmann; B. Schwab; A. Schwind; U. Seehausen; F. Sefkow; M. Seidel; R. Sell; A. Semenov; V. Shekelyan; I. Sheviakov; H. Shooshtari; L. N. Shtarkov; G. Siegmon; U. Siewert; Y. Sirois; I. O. Skillicorn; P. Smirnov; J. R. Smith; V. Solochenko; Y. Soloviev; J. Spiekermann; H. Spitzer; R. Starosta; M. Steenbock; P. Steffen; R. Steinberg; B. Stella; K. Stephens; J. Stier; J Strachota; U. Stösslein; K. Stolze; U. Straumann; W. Struczinski; J. P. Sutton; S. Tapprogge; R. E. Taylor; V. Tchernyshov; C. Thiebaux; G. Thompson; P. Truöl; J. Turnau; J. Tutas; P. Uelkes; A. Usik; S. Valkár; A. Valkárová; C. Vallée; P. Van Esch; P. Van Mechelen; A. Vartapetian; Y. Vazdik; M. Vecko; P. Verrecchia; G. Villet; K. Wacker; A. Wagener

    1995-01-01

    We present an experimental study of theep?e?+p andep?e?+X processes using data recorded by the H1 detector in 1993 at the electron-proton collider HERA. These processes are employed to measure the luminosity with an accuracy of 4.5 %. A subsample of theep?e?+X events in which the hard photon is detected at angles ??' = 0.45 mrad with respect to the incident

  18. Radiation hardness assurance and reliability testing of InGaAs photodiodes for optical control links for the CMS experiment

    Microsoft Academic Search

    K. Gill; M. Axer; S. Dris; R. Grabit; R. Macias; E. Noah; J. Troska; F. Vasey

    2005-01-01

    A radiation hard 80 Mbit\\/s digital optical link system with 7200 fiber channels is being produced for the CMS Experiment at CERN. A series of tests including radiation damage and thermally accelerated aging have been made to qualify and assure the radiation hardness and reliability of InGaAs photodiodes intended for use in this system.

  19. Component separation for cosmic microwave background radiation

    NASA Astrophysics Data System (ADS)

    Fernández-Cobos, R.; Vielva, P.; Barreiro, R. B.; Martínez-González, E.

    2011-11-01

    Cosmic microwave background (CMB) radiation data obtained by different experiments contains, besides the desired signal, a superposition of microwave sky contributions mainly due to, on the one hand, synchrotron radiation, free-free emission and re-emission of dust clouds in our galaxy; and, on the other hand, extragalactic sources. We present an analytical method, using a wavelet decomposition on the sphere, to recover the CMB signal from microwave maps. Being applied to both temperature and polarization data, it is shown as a significant powerful tool when it is used in particularly polluted regions of the sky. The applied wavelet has the advantages of requiring little computering time in its calculations being adapted to the HEALPix pixelization scheme (which is the format that the community uses to report the CMB data) and offering the possibility of multi-resolution analysis. The decomposition is implemented as part of a template fitting method, minimizing the variance of the resulting map. The method was tested with simulations of WMAP data and results have been positive, with improvements up to 12% in the variance of the resulting full sky map and about 3% in low contaminate regions. Finally, we also present some preliminary results with WMAP data in the form of an angular cross power spectrum C_?^{TE}, consistent with the spectrum offered by WMAP team.

  20. Design and development of a hard tube flexible radiator system

    NASA Technical Reports Server (NTRS)

    Hixon, C. W.

    1980-01-01

    The construction and operational characteristics of an extended life flexible radiator panel is described. The radiator panel consists of a flexible fin laminate and stainless steel flow tubes designed for a 90 percent probability of surviving 5 years in an Earth orbit micrometeoroid environment. The radiator panel rejects 1.1 kW sub t of heat into an environmental sink temperature of 0 F. Total area is 170 square feet and the panel extends 25 feet in the fully deployed position. When retracted the panel rolls onto a 11.5 inch diameter by 52 inch long storage drum, for a final stored diameter of 22 inches.

  1. Estimation of surface longwave radiation components from ground-based historical net radiation and weather data

    Microsoft Academic Search

    Gi-Hyeon Park; Xiaogang Gao; Soroosh Sorooshian

    2008-01-01

    A methodology for estimating ground upwelling, clear-sky and cloud downwelling longwave radiations (L?, Lsky?, and Lcld?) and net shortwave radiation (Sn) at 30-min temporal scales based on long-term ground-based net radiations and meteorological observations is described. Components of surface radiation can be estimated from empirical models, cloud radiation models, and remote sensing observations. The proposed method combines the local calibration

  2. Drag induced radiative loss from semi-hard heavy quarks

    E-print Network

    Abir, Raktim

    2015-01-01

    The case of gluon bremsstrahlung off a heavy quark in extended nuclear matter is revisited within the higher twist formalism. In particular, the in-medium modification of "semi-hard" heavy quarks is studied, where the momentum of the heavy quark is larger but comparable to the mass of the heavy quark ($p \\gtrsim M$). In contrast to all prior calculations, where the gluon emission spectrum is entirely controlled by the transverse momentum diffusion parameter ($\\hat q$), both for light and heavy quarks, in this work, we demonstrate that the gluon emission spectrum for a heavy quark (unlike that for flavors) is also sensitive to $\\hat e$, which so far has been used to quantify the amount of light-cone drag experienced by a parton. This mass dependent effect, due to the non-light-like momentum of a semi-hard heavy-quark, leads to an additional energy loss term for heavy-quarks, while resulting in a negligible modification of light flavor (and high energy heavy flavor) loss. This result can be used to estimate the...

  3. 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....

  4. Radiation hardness of silicon photomultipliers under 60Co ?-ray irradiation

    NASA Astrophysics Data System (ADS)

    Pagano, R.; Lombardo, S.; Palumbo, F.; Sanfilippo, D.; Valvo, G.; Fallica, G.; Libertino, S.

    2014-12-01

    Radiation damage in silicon photomultipliers (SiPM) caused by exposure to 60Co ?-rays is experimentally evaluated and discussed. SiPM devices were irradiated to doses up to 9.4 kGy. Dark current, dark count rate, gain, single photon counting capability, and cross-talk probability among SiPM pixels are evaluated as a function of irradiation dose.

  5. 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...

  6. 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

  7. 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

  8. Suzaku broad-band spectrum of 4U 1705-44: probing the reflection component in the hard state

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

    Iron emission lines at 6.4-6.97 keV, identified with K? 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 disc 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 disc. 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 disc radius is Rin = 17 ± 5Rg (where Rg is the gravitational radius, GM/c2), the emissivity dependence from the disc radius is r-2.5 ± 0.5, the inclination angle with respect to the line of sight is i = 43° ± 5°, and the outer radius of the emitting region in the disc is Rout > 200Rg. We note that the accretion disc does not appear to be truncated at large radii, although the source is in a hard state at ˜3 per cent of the Eddington luminosity for a neutron star. We also find evidence of a broad emission line at low energies, at 3.03 ± 0.03 keV, compatible with emission from mildly ionized argon (Ar XVI-XVII). Argon transitions are not included in the self-consistent reflection models that we used and we therefore added an extra component to our model to fit this feature. The low-energy line appears compatible with being smeared by the same inner disc parameters found for the reflection component.

  9. Laser synchrotron radiation as a compact source of tunable, short pulse hard X-rays

    Microsoft Academic Search

    E. Esarey; P. Sprangle; A. Ting; S. K. Ride

    1993-01-01

    A compact laser synchrotron source (LSS) is proposed as a means of generating tunable, narrow bandwidth, ultrashort pulses of hard X-rays. The LSS is based on the Thomson backscattering of intense laser radiation from a counterstreaming electron beam. Advances in both compact ultraintense solid-state lasers and high brightness rf linac beams make the LSS an attractive compact source of high

  10. Hartmut Sadrozinski RD50 5/06/04 Development of Radiation-hard Front Electronics

    E-print Network

    California at Santa Cruz, University of

    Hartmut Sadrozinski RD50 5/06/04 Development of Radiation-hard Front Electronics for sLHC = Investigation of the SiGe Process David E. Dorfan, Alexander A. Grillo, Hartmut F.-W. Sadrozinski, Bruce Schumm 5/06/04 Synergy of detectors and readout electronics. "Detectors and Electronics: Are These Two

  11. Super-radiation hard detector technologies: 3-D and widegap detectors

    Microsoft Academic Search

    M. Rahman; A. Al-Ajili; R. Bates; A. Blue; W. Cunningham; F. Doherty; M. Glaser; L. Haddad; M. Horn; J. Melone; M. Mikuz; T. Quinn; P. Roy; V. O'Shea; K. M. Smith; J. Vaitkus; V. Wright

    2004-01-01

    The radiation hardness of semiconductor detectors for harsh environments, including nuclear, space, and particle physics, may be enhanced by a number of strategies. We examine the use of materials alternative to silicon, namely silicon carbide and gallium nitride, as well as a nonconventional geometry called \\

  12. ELECTROMECHANICAL, THERMAL PROPERTIES AND RADIATION HARDNESS TESTS OF PIEZOELECTRIC ACTUATORS AT LOW

    E-print Network

    Paris-Sud XI, Université de

    drawing of the test-cell (See [2] for details). VACUUM CHAMBER Feedthrough port Stainless steel ball #12ELECTROMECHANICAL, THERMAL PROPERTIES AND RADIATION HARDNESS TESTS OF PIEZOELECTRIC ACTUATORS for measuring their electromechanical and thermal properties for T in the range 1.8 K-300 K. Different

  13. RD50 Status Report 2008 - Radiation hard semiconductor devices for very high luminosity colliders

    E-print Network

    Balbuena, Juan Pablo; Campabadal, Francesca; Díez, Sergio; Fleta, Celeste; Lozano, Manuel; Pellegrini, Giulio; Rafí, Joan Marc; Ullán, Miguel; Creanza, Donato; De Palma, Mauro; Fedele, Francesca; Manna, Norman; Kierstead, Jim; Li, Zheng; Buda, Manuela; Lazanu, Sorina; Pintilie, Lucian; Pintilie, Ioana; Popa, Andreia-Ioana; Lazanu, Ionel; Collins, Paula; Fahrer, Manuel; Glaser, Maurice; Joram, Christian; Kaska, Katharina; La Rosa, Alessandro; Mekki, Julien; Moll, Michael; Pacifico, Nicola; Pernegger, Heinz; Goessling, Claus; Klingenberg, Reiner; Weber, Jens; Wunstorf, Renate; Roeder, Ralf; Stolze, Dieter; Uebersee, Hartmut; Cihangir, Selcuk; Kwan, Simon; Spiegel, Leonard; Tan, Ping; Bruzzi, Mara; Focardi, Ettore; Menichelli, David; Scaringella, Monica; Breindl, Michael; Eckert, Simon; Köhler, Michael; Kuehn, Susanne; Parzefall, Ulrich; Wiik, Liv; Bates, Richard; Blue, Andrew; Buttar, Craig; Doherty, Freddie; Eklund, Lars; Bates, Alison G; Haddad, Lina; Houston, Sarah; James, Grant; Mathieson, Keith; Melone, J; OShea, Val; Parkes, Chris; Pennicard, David; Buhmann, Peter; Eckstein, Doris; Fretwurst, Eckhart; Hönniger, Frank; Khomenkov, Vladimir; Klanner, Robert; Lindström, Gunnar; Pein, Uwe; Srivastava, Ajay; Härkönen, Jaakko; Lassila-Perini, Katri; Luukka, Panja; Mäenpää, Teppo; Tuominen, Eija; Tuovinen, Esa; Eremin, Vladimir; Ilyashenko, Igor; Ivanov, Alexandr; Kalinina, Evgenia; Lebedev, Alexander; Strokan, Nikita; Verbitskaya, Elena; Barcz, Adam; Brzozowski, Andrzej; Kaminski, Pawel; Kozlowski, Roman; Kozubal, Michal; Luczynski, Zygmunt; Pawlowski, Marius; Surma, Barbara; Zelazko, Jaroslaw; de Boer, Wim; Dierlamm, Alexander; Frey, Martin; Hartmann, Frank; Zhukov, Valery; Barabash, L; Dolgolenko, A; Groza, A; Karpenko, A; Khivrich, V; Lastovetsky, V; Litovchenko, P; Polivtsev, L; Campbell, Duncan; Chilingarov, Alexandre; Fox, Harald; Hughes, Gareth; Jones, Brian Keith; Sloan, Terence; Samadashvili, Nino; Tuuva, Tuure; Affolder, Anthony; Allport, Phillip; Bowcock, Themis; Casse, Gianluigi; Vossebeld, Joost; Cindro, Vladimir; Dolenc, Irena; Kramberger, Gregor; Mandic, Igor; Mikuž, Marko; Zavrtanik, Marko; Zontar, Dejan; Gil, Eduardo Cortina; Grégoire, Ghislain; Lemaitre, Vincent; Militaru, Otilia; Piotrzkowski, Krzysztof; Kazuchits, Nikolai; Makarenko, Leonid; Charron, Sébastien; Genest, Marie-Helene; Houdayer, Alain; Lebel, Celine; Leroy, Claude; Aleev, Andrey; Golubev, Alexander; Grigoriev, Eugene; Karpov, Aleksey; Martemianov, Alxander; Rogozhkin, Sergey; Zaluzhny, Alexandre; Andricek, Ladislav; Beimforde, Michael; Macchiolo, Anna; Moser, Hans-Günther; Nisius, Richard; Richter, Rainer; Gorelov, Igor; Hoeferkamp, Martin; Metcalfe, Jessica; Seidel, Sally; Toms, Konstantin; Hartjes, Fred; Koffeman, Els; van der Graaf, Harry; Visschers, Jan; Kuznetsov, Andrej; Sundnes Løvlie, Lars; Monakhov, Edouard; Svensson, Bengt G; Bisello, Dario; Candelori, Andrea; Litovchenko, Alexei; Pantano, Devis; Rando, Riccardo; Bilei, Gian Mario; Passeri, Daniele; Petasecca, Marco; Pignatel, Giorgio Umberto; Bernardini, Jacopo; Borrello, Laura; Dutta, Suchandra; Fiori, Francesco; Messineo, Alberto; Bohm, Jan; Mikestikova, Marcela; Popule, Jiri; Sicho, Petr; Tomasek, Michal; Vrba, Vaclav; Broz, Jan; Dolezal, Zdenek; Kodys, Peter; Tsvetkov, Alexej; Wilhelm, Ivan; Chren, Dominik; Horazdovsky, Tomas; Kohout, Zdenek; Pospisil, Stanislav; Solar, Michael; Sopko, Vít; Sopko, Bruno; Uher, Josef; Horisberger, Roland; Radicci, Valeria; Rohe, Tilman; Bolla, Gino; Bortoletto, Daniela; Giolo, Kim; Miyamoto, Jun; Rott, Carsten; Roy, Amitava; Shipsey, Ian; Son, SeungHee; Demina, Regina; Korjenevski, Sergey; Grillo, Alexander; Sadrozinski, Hartmut; Schumm, Bruce; Seiden, Abraham; Spence, Ned; Hansen, Thor-Erik; Artuso, Marina; Borgia, Alessandra; Lefeuvre, Gwenaelle; Guskov, J; Marunko, Sergey; Ruzin, Arie; Tylchin, Tamir; Boscardin, Maurizio; Dalla Betta, Gian - Franco; Gregori, Paolo; Piemonte, Claudio; Ronchin, Sabina; Zen, Mario; Zorzi, Nicola; Garcia, Carmen; Lacasta, Carlos; Marco, Ricardo; Marti i Garcia, Salvador; Minano, Mercedes; Soldevila-Serrano, Urmila; Gaubas, Eugenijus; Kadys, Arunas; Kazukauskas, Vaidotas; Sakalauskas, Stanislavas; Storasta, Jurgis; Vidmantis Vaitkus, Juozas; CERN. Geneva. The LHC experiments Committee; LHCC

    2010-01-01

    The objective of the CERN RD50 Collaboration is the development of radiation hard semiconductor detectors for very high luminosity colliders, particularly to face the requirements of a possible upgrade scenario of the LHC.This document reports the status of research and main results obtained after the sixth year of activity of the collaboration.

  14. Irradiation facility at the IBR-2 reactor for investigating material radiation hardness

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

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

  15. Elsevier Science 1 Radiation-hard ASICs for LHC optical data transmission

    E-print Network

    Gan, K. K.

    Elsevier Science 1 Radiation-hard ASICs for LHC optical data transmission K.K. Gan,* H.P. Kagan, R several ASICs for possible applications in a new ATLAS pixel layer for the first phase of the LHC luminosity upgrade. The ASICs include a high-speed driver for the VCSEL, a receiver/decoder to decode

  16. Radiation-hard ASICs for optical data transmission in the first phase of the LHC upgrade

    E-print Network

    Gan, K. K.

    Radiation-hard ASICs for optical data transmission in the first phase of the LHC upgrade K.K. Gan a have designed two ASICs for possible applications in the optical links of a new layer of the pixel. The ASICs include a high-speed driver for the VCSEL and a receiver/decoder to decode the signal received

  17. Gluon Radiation off Hard Quarks in a Nuclear Environment: Opacity Expansion

    E-print Network

    Urs Achim Wiedemann

    2000-08-15

    We study the relation between the Baier-Dokshitzer-Mueller-Peigne-Schiff (BDMPS) and Zakharov formalisms for medium-induced gluon radiation off hard quarks, and the radiation off very few scattering centers. Based on the non-abelian Furry approximation for the motion of hard partons in a spatially extended colour field, we derive a compact diagrammatic and explicitly colour trivial expression for the N-th order term of the kt-differential gluon radiation cross section in an expansion in the opacity of the medium. Resumming this quantity to all orders in opacity, we obtain Zakharov's path-integral expression (supplemented with a regularization prescription). This provides a new proof of the equivalence of the BDMPS and Zakharov formalisms which extends previous arguments to the kt-differential cross section. We give explicit analytical results up to third order in opacity for both the gluon radiation cross section of free incoming and of in-medium produced quarks. The N-th order term in the opacity expansion of the radiation cross section is found to be a convolution of the radiation associated to N-fold rescattering and a readjustment of the probabilities that rescattering occurs with less than N scattering centers. Both informations can be disentangled by factorizing out of the radiation cross section a term which depends only on the mean free path of the projectile. This allows to infer analytical expressions for the totally coherent and totally incoherent limits of the radiation cross section to arbitrary orders in opacity.

  18. Experimental examination of scintillations in the hard component of cosmic rays near sea level

    NASA Astrophysics Data System (ADS)

    Benson, R.; Green, P.

    An instrument designed to observe scintillations in the muon component of the secondary cosmic radiation recently constructed at Texas A&M University is described. The large scintillators in the instrument are separated by lead. Counting information is recorded in short time intervals and stored through microcomputer control on permanent disk files. The data are analyzed to establish the power spectrum of the muon intensity. A best fit to preliminary data shows the fluctuations to be consistent with a certain power law. The theory that cosmic ray scintillations derive from various irregularities in the magnetic fields through which the rays must travel before being detected is tested using ground-level muons that are more directly related to the primary radiation.

  19. Radiation mitigating properties of the lignan component in flaxseed

    PubMed Central

    2013-01-01

    Background Wholegrain flaxseed (FS), and its lignan component (FLC) consisting mainly of secoisolariciresinol diglucoside (SDG), have potent lung radioprotective properties while not abrogating the efficacy of radiotherapy. However, while the whole grain was recently shown to also have potent mitigating properties in a thoracic radiation pneumonopathy model, the bioactive component in the grain responsible for the mitigation of lung damage was never identified. Lungs may be exposed to radiation therapeutically for thoracic malignancies or incidentally following detonation of a radiological dispersion device. This could potentially lead to pulmonary inflammation, oxidative tissue injury, and fibrosis. This study aimed to evaluate the radiation mitigating effects of FLC in a mouse model of radiation pneumonopathy. Methods We evaluated FLC-supplemented diets containing SDG lignan levels comparable to those in 10% and 20% whole grain diets. 10% or 20% FLC diets as compared to an isocaloric control diet (0% FLC) were given to mice (C57/BL6) (n=15-30 mice/group) at 24, 48, or 72-hours after single-dose (13.5 Gy) thoracic x-ray treatment (XRT). Mice were evaluated 4 months post-XRT for blood oxygenation, lung inflammation, fibrosis, cytokine and oxidative damage levels, and survival. Results FLC significantly mitigated radiation-related animal death. Specifically, mice fed 0% FLC demonstrated 36.7% survival 4 months post-XRT compared to 60–73.3% survival in mice fed 10%-20% FLC initiated 24–72 hours post-XRT. FLC also mitigated radiation-induced lung fibrosis whereby 10% FLC initiated 24-hours post-XRT significantly decreased fibrosis as compared to mice fed control diet while the corresponding TGF-beta1 levels detected immunohistochemically were also decreased. Additionally, 10-20% FLC initiated at any time point post radiation exposure, mitigated radiation-induced lung injury evidenced by decreased bronchoalveolar lavage (BAL) protein and inflammatory cytokine/chemokine release at 16 weeks post-XRT. Importantly, neutrophilic and overall inflammatory cell infiltrate in airways and levels of nitrotyrosine and malondialdehyde (protein and lipid oxidation, respectively) were also mitigated by the lignan diet. Conclusions Dietary FLC given early post-XRT mitigated radiation effects by decreasing inflammation, lung injury and eventual fibrosis while improving survival. FLC may be a useful agent, mitigating adverse effects of radiation in individuals exposed to incidental radiation, inhaled radioisotopes or even after the initiation of radiation therapy to treat malignancy. PMID:23557217

  20. Absorption of laser radiation by components of blood

    NASA Astrophysics Data System (ADS)

    Kozakov, Oleg N.

    2008-05-01

    Considering propagation of radiation through light-scattering layers (such as paints, photomaterials, foils, skin etc.), one usually finds out the total energy absorbed by the layer using any experimental, analytical or computational methods. It is insufficient for solving some practical problems. It is important to know the distribution of the absorbed energy among disperse layer components, i.e. among a disperse phase and a bulk. The results of computation by Monte-Carlo technique of absorption of radiation for a blood as a whole, and separately for plasma and for erythrocyte. Computations were performed for wavelength ?=633 nm.

  1. Polymer materials and component evaluation in acidic-radiation environments

    Microsoft Academic Search

    M. Celina; K. T. Gillen; G. M. Malone; R. L. Clough; W. H. Nelson

    2001-01-01

    Polymeric materials used for cable\\/wire insulation, electrical connectors, O-rings, seals, and in critical components such as motors, level switches and resistive thermo-devices were evaluated under accelerated degradation conditions in combined radiation-oxidative elevated-temperature acidic-vapor (nitric\\/oxalic) environments relevant to conditions in isotope processing facilities. Experiments included the assessment of individual materials such as PEEK, polyimides, polyolefin based cable insulation, EPDM rubbers, various

  2. 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

  3. HTLT oxygenated silicon detectors: radiation hardness and long-term stability

    Microsoft Academic Search

    Z. Li; B. Dezillie; M. Bruzzi; W. Chen; V. Eremin; E. Verbitskaya; P. Weilhammer

    2001-01-01

    Silicon detectors fabricated by BNLs high-temperature, long time (HTLT) oxidation technology have been characterized using various techniques for material\\/detector properties and radiation hardness with respect to gamma, proton and neutron irradiation. It has been found that a uniform oxygen distribution with a concentration of 4×1017\\/cm3 has been achieved in high-resistivity FZ silicon with our HTLT technology. With the standard HTLT

  4. A Radiation-Hard Analog Memory In The AVLSI-RA Process

    SciTech Connect

    Britton, C.L. Jr.; Wintenberg, A.L.; Read, K.F.; Simpson, M.L.; Young, G.R. [Oak Ridge National Lab., TN (United States); Clonts, L.G., Kennedy, E.J., Smith, R.S., Swann, B.K. [University of Tennessee, Knoxville (United States); Musser, J.A. [Indiana Univ., Bloomington, IN (United States). Dept. of Physics

    1995-12-31

    A radiation hardened analog memory for an Interpolating Pad Camber has been designed at Oak Ridge National Laboratory and fabricated by Harris Semiconductor in the AVLSI-RA CMOS process. The goal was to develop a rad-hard analog pipeline that would deliver approximately 9-bit performance, a readout settling time of 500ns following read enable, an input and output dynamic range of +/-2.25V, a corrected rms pedestal of approximately 5mV or less, and a power dissipation of less than 10mW/channel. The pre- and post-radiation measurements to 5MRad are presented.

  5. The impact of morphology upon the radiation hardness of ZnO layers.

    PubMed

    Burlacu, A; Ursaki, V V; Skuratov, V A; Lincot, D; Pauporte, T; Elbelghiti, H; Rusu, E V; Tiginyanu, I M

    2008-05-28

    It is shown that ZnO nanorods and nanodots grown by MOCVD exhibit enhanced radiation hardness against high energy heavy ion irradiation as compared to bulk layers. The decrease of the luminescence intensity induced by 130 MeV Xe(23+) irradiation at a dose of 1.5 × 10(14) cm(-2) in ZnO nanorods is nearly identical to that induced by a dose of 6 × 10(12) cm(-2) in bulk layers. The damage introduced by irradiation is shown to change the nature of electronic transitions responsible for luminescence. The change of excitonic luminescence to the luminescence related to the tailing of the density of states caused by potential fluctuations occurs at an irradiation dose around 1 × 10(14) cm(-2) and 5 × 10(12) cm(-2) in nanorods and bulk layers, respectively. More than one order of magnitude enhancement of radiation hardness of ZnO nanorods grown by MOCVD as compared to bulk layers is also confirmed by the analysis of the near-bandgap photoluminescence band broadening and the behavior of resonant Raman scattering lines. The resonant Raman scattering analysis demonstrates that ZnO nanostructures are more radiation-hard as compared to nanostructured GaN layers. High energy heavy ion irradiation followed by thermal annealing is shown to be a way for the improvement of the quality of ZnO nanorods grown by electrodeposition and chemical bath deposition. PMID:21730593

  6. Comparison of hard X-ray spectra obtained by spectrometers on Hinotori and SMM and detection of 'superhot' component

    NASA Technical Reports Server (NTRS)

    Nitta, Nariaki

    1988-01-01

    Hard X-ray spectra in solar flares obtained by the broadband spectrometers aboard Hinotori and SMM are compared. Within the uncertainty brought about by assuming the typical energy of the background X-rays, spectra by the Hinotori spectrometer are usually consistent with those by the SMM spectrometer for flares in 1981. On the contrary, flares in 1982 persistently show 20-50-percent higher flux by Hinotori than by SMM. If this discrepancy is entirely attributable to errors in the calibration of energy ranges, the errors would be about 10 percent. Despite such a discrepancy in absolute flux, in the the decay phase of one flare, spectra revealed a hard X-ray component (probably a 'superhot' component) that could be explained neither by emission from a plasma at about 2 x 10 to the 7th K nor by a nonthermal power-law component. Imaging observations during this period show hard X-ray emission nearly cospatial with soft X-ray emission, in contrast with earlier times at which hard and soft X-rays come from different places.

  7. Optimization of radiation hardness and charge collection of edgeless silicon pixel sensors for photon science

    E-print Network

    Zhang, Jiaguo; Pennicard, David; Sarajlic, Milija; Graafsma, Heinz

    2014-01-01

    Recent progress in active-edge technology of silicon sensors enables the development of large-area tiled silicon pixel detectors with small dead space between modules by utilizing edgeless sensors. Such technology has been proven in successful productions of ATLAS and Medipix-based silicon pixel sensors by a few foundries. However, the drawbacks of edgeless sensors are poor radiation hardness for ionizing radiation and non-uniform charge collection by edge pixels. In this work, the radiation hardness of edgeless sensors with different polarities has been investigated using Synopsys TCAD with X-ray radiation-damage parameters implemented. Results show that if no conventional guard ring is present, none of the current designs are able to achieve a high breakdown voltage (typically < 30 V) after irradiation to a dose of ~10 MGy. In addition, a charge-collection model has been developed and was used to calculate the charges collected by the edge pixels of edgeless sensors when illuminated with X-rays. The mode...

  8. Recent Progress in CERN RD39: Radiation Hard Cryogenic Silicon Detectors for Applications in LHC Experiments and Their Future Upgrades

    Microsoft Academic Search

    E. Tuominen; P. Anbinderis; T. Anbinderis; R. Bates; W. de Boer; E. Borchi; M. Bruzzi; C. Buttar; W. Chen; V. Cindro; S. Czellar; A. Dierlamm; V. Eremin; E. Gaubas; J. Harkonen; E. Heijne; I. Ilyashenko; V. Kalesinskas; M. J. Kortelainen; T. Lampen; Z. Li; P. Luukka; I. Mandic; D. Menichelli; M. Mikuz; O. Militaru; S. Mueller; T. Maenpaa; T. O. Niinikoski; V. O'Shea; C. Parkes; K. Piotrzkowski; S. Pirollo; P. Pusa; J. Raisanen; E. Tuovinen; J. Vaitkus; E. Verbitskaya; S. Vayrynen; M. Zavrtanik

    2009-01-01

    CERN RD39 Collaboration develops radiation-hard cryogenic silicon detectors. Recently, we have demonstrated improved radiation hardness in novel Current Injected Detectors (CID). For detector characterization, we have applied cryogenic Transient Current Technique (C-TCT). In beam tests, heavily irradiated CID detector showed capability for particle detection. Our results show that the CID detectors are operational at the temperature -50degC after the fluence

  9. Recent progress in CERN RD39 Radiation hard cryogenic silicon detectors for applications in LHC experiments and their future upgrades

    E-print Network

    Tuominen, E; Anbinderis, T; Bates, R; de Boer, W; Borchi, E; Bruzzi, M; Buttar, C; Chen, W; Cindro, V; Czellar, S; Dierlamm, A; Eremin, V; Gaubas, E; Härkönen, J; Heijne, E; Ilyashenko, I; Kalesinskas, V; Kortelainen, M J; Lampen, T; Li, Z; Luukka, P; Mandic, I; Menichelli, D; Mikuz, M; Militaru, O; Mueller, S; Mäenpää, T; Niinikoski, T O; O'Shea, V; Parkes, C; Piotrzkowski, K; Pirollo, S; Pusa, P; Räisänen, J; Tuovinen, E.; Vaitkus, J; Verbitskaya, E; Väyrynen, S; Zavrtanik, M; 10.1109/TNS.2009.2013950

    2009-01-01

    CERN RD39 Collaboration develops radiation-hard cryogenic silicon detectors. Recently, we have demonstrated improved radiation hardness in novel Current Injected Detectors (CID). For detector characterization, we have applied cryogenic Transient Current Technique (C-TCT). In beam tests, heavily irradiated CID detector showed capability for particle detection. Our results show that the CID detectors are operational at the temperature -50degC after the fluence of 1 times 1016 1 MeV neutron equivalent/cm2.

  10. Recent progress in CERN RD39: radiation hard cryogenic silicon detectors for applications in LHC experiments and their future upgrades

    Microsoft Academic Search

    E. Tuominen; P. Anbinderis; T. Anbinderis; R. Bates; W. de Boer; E. Borchi; M. Bruzzi; C. Buttar; W. Chen; V. Cindro; S. Czellar; V. Eremin; A. Furgeri; E. Gaubas; J. Harkonen; E. Heijne; I. Ilyashenko; V. Kalesinskas; M. J. Kortelainen; M. Krause; T. Lampen; Z. Li; P. Luukka; I. Mandic; D. Menichelli; M. Mikuz; O. Militaru; S. Mueller; T. Maenpaa; T. O. Niinikoski; V. O'Shea; C. Parkes; K. Piotrzkowski; S. Pirollo; P. Pusa; J. Raisanen; X. Rouby; E. Tuovinen; J. Vaitkus; E. Verbitskaya; S. Vayrynen; M. Zavrtanik

    2008-01-01

    CERN RD39 Collaboration develops radiation-hard cryogenic silicon detectors. Recently, we have demonstrated improved radiation hardness in novel Current Injected Detectors (CID). For detector characterization, we have applied cryogenic Transient Current Technique (C-TCT). In beam tests, heavily irradiated CID detector showed capability for particle detection. Our results show that the CID detectors are operational at the temperature -50°C after 1016 1

  11. 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

  12. 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.

  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. 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.

  15. Recent results from the CERN RD39 Collaboration on super-radiation hard cryogenic silicon detectors for LHC and LHC upgrade

    Microsoft Academic Search

    J. Harkonen; M. Abreu; P. Anbinderis; T. Anbinderis; N. D’Ambrosio; W. de Boer; E. Borchi; K. Borer; M. Bruzzi; S. Buontempo; W. Chen; V. Cindro; B. Dezillie; A. Dierlamm; V. Eremin; E. Gaubas; V. Gorbatenko; V. Granata; E. Grigoriev; S. Grohmann; F. Hauler; E. Heijne; S. Heising; O. Hempel; R. Herzog; I. Ilyashenko; S. Janos; L. Jungermann; V. Kalesinskas; J. Kapturauskas; R. Laiho; Z. Li; P. Luukka; I. Mandic; R. De Masi; D. Menichelli; M. Mikuz; O. Militaru; T. O. Niinikoski; G. Nuessle; V. O’Shea; S. Pagano; S. Paul; B. Perea Solano; K. Piotrzkowski; S. Pirollo; K. Pretzl; M. Rahman; P. Rato Mendes; X. Rouby; G. Ruggiero; K. Smith; P. Sousa; E. Tuominen; E. Tuovinen; J. Vaitkus; E. Verbitskaya; C. Da Viá; L. Vlasenko; M. Vlasenko; E. Wobst; M. Zavrtanik

    2004-01-01

    The CERN RD39 Collaboration is developing super-radiation hard cryogenic Si detectors for applications in experiments of the LHC and the future LHC Upgrade. Radiation hardness up to the fluence of 1016neq\\/cm2 is required in the future experiments. Significant improvement in the radiation hardness of silicon sensors has taken place during the past years. However, 1016neq\\/cm2 is well beyond the radiation

  16. Radiation hardness of plastic scintillating fiber against fast neutron and [gamma]-ray irradiation

    SciTech Connect

    Murakami, Akira; Yoshinaka, Hideki; Goto, Minehiko (Saga Univ. (Japan). Dept. of Physics)

    1993-08-01

    In future collider experiments, where a background radiation level is estimated to be very high, e.g. around 10[sup 2] [approximately] 10[sup 5] Gy/yr and 10[sup 11] [approximately] 10[sup 14] n/cm[sup 2]/yr at SSC, the detectors operating around the collision point in the experiments will encounter a considerable amount of radiation. Therefore, the detectors, especially the calorimeter, are required to be resistive against high radiation levels. From this point of view, it is of great importance to study the effects of radiation damage on the performance of the detectors. The authors report preliminary results of measurements of radiation hardness of the plastic scintillating fiber Kuraray SCSF-81 against irradiation with fast neutrons and [sup 60]Co [gamma]-rays in the region of the neutron fluence from 1 [times] 10[sup 11] to 5 [times] 10[sup 13] n/cm[sup 2] and the integrated [gamma]-ray dose from 890 to 10[sup 5] Gy, respectively. Deterioration of both intrinsic light yield and light transmittance of the SCSF-81 has been studied.

  17. Nuclear Instruments and Methods in Physics Research A 490 (2002) 444455 Radiation-hardness studies of high OH

    E-print Network

    Akgun, Ugur

    2002-01-01

    Nuclear Instruments and Methods in Physics Research A 490 (2002) 444­455 Radiation-hardness studies. Zeyreke a Cukurova University, Adana, Turkey b Texas Tech University, Lubbock, USA c University of Iowa testing and measurement of fibre parameters; Radiation effects on optical elements; Fibres, synthetic

  18. Foreign technology assessment: Environmental evaluation of a radiation-hard oscillator/divider

    NASA Astrophysics Data System (ADS)

    Dvorack, M. A.

    1993-03-01

    Salford Electrical Instruments, Ltd., and the General Electric Company's Hirst Research Center, under contract to the United Kingdom's (UK) Ministry of Defence, developed a radiation-hard, leadless chip-carrier-packaged oscillator/divider. Two preproduction clocks brought to Sandia National Laboratories (SNL) by a potential SNL customer underwent mechanical and thermal environmental evaluation. Because of the subsequent failure of one device and the deteriorating condition of another device, the devices were not subjected to radiation tests. The specifics of the environmental evaluation performed on these two clocks and the postmortem analysis of one unit, which ultimately failed, are described. Clock startup time versus temperature studies were also performed and compared to an SNL-designed clock having the same fundamental frequency.

  19. Radiation hard humidity sensors based on polyimide-coated fiber Bragg gratings

    NASA Astrophysics Data System (ADS)

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

    2013-05-01

    We report on a feasibility analysis for the development of fiber optic humidity sensors to be applied in high-energy physics applications and in particular in experiments actually running at the European Organization for Nuclear Research (CERN). Due to the stringent sensors requirements concerning radiation hardness capability and low temperature operation, we focus our attention on the investigation of fiber optic humidity sensors based on polyimmide (PI)-coated Fiber Bragg Gratings (FBGs). Data here reported, obtained during a wide experimental campaign carried out in the laboratories of CERN, demonstrate that the selected technological platform is able to perform relative humidity (RH) measurements with percent resolution in the temperature range -15-20°C as well as in presence of ionizing radiations up to 10KGray, largely outperforming conventional humidity sensors, currently employed within CERN environment.

  20. Soft X-ray components in the hard state of accreting black holes

    E-print Network

    Caroline D'Angelo; Dimitrios Giannios; Cornelis Dullemond; Henk Spruit

    2008-07-29

    Recent observations of two black hole candidates (GX 339-4 and J1753.5-0127) in the low-hard state (L_X/L_Edd ~ 0.003-0.05) suggest the presence of a cool accretion disk very close to the innermost stable orbit of the black hole. This runs counter to models of the low-hard state in which the cool disk is truncated at a much larger radius. We study the interaction between a moderately truncated disk and a hot inner flow. Ion-bombardment heats the surface of the disk in the overlap region between a two-temperature advection-dominated accretion flow and standard accretion disk, producing a hot (kT_e ~70 keV) layer on the surface of the cool disk. The hard X-ray flux from this layer heats the inner parts of the underlying cool disk, producing a soft X-ray excess. Together with interstellar absorption these effects mimic the thermal spectrum from a disk extending to the last stable orbit. The results show that soft excesses in the low-hard state are a natural feature of truncated disk models.

  1. 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 ...

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

    E-print Network

    Rho, Sangig

    2005-02-17

    . . . . . . . . . . . 58 2. The Deserialization of Java RMI Server Objects . . . . 61 3. Java Classes for Agile Objects Migration Mechanism . 62 a. Interface ao.migration.Migratable . . . . . . . . . 62 b. Class ao.migration.DataSender . . . . . . . . . . . 64 c. Class ao...-defined services either to a client program (which can in turn be a component) or to other components. Besides their well-defined ser- vice interface, components are opaque: They do not make internal implementation details available to their environment. Component...

  3. 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.

  4. Radiation hardness of high resistivity magnetic Czochralski silicon detectors after gamma, neutron, and proton radiations

    Microsoft Academic Search

    Zheng Li; Jaakko Harkonen; Wei Chen; J. Kierstead; Panja Luukka; Eija Tuominen; Etuovine Tuovinen; Elea Verbitskaya; Vladimir Eremin

    2004-01-01

    High resistivity magnetic Czochralski Si detectors were irradiated with 60Co gamma rays, neutrons, and protons to various doses\\/fluences, along with control float zone Si detectors. 1) It has been found that for gamma radiation, magnetic Czochralski Si detectors behave similarly to the high-temperature, long-time (HTLT) oxygenated float zone Si detectors. There is no space charge sign inversion and there is

  5. Effects of gamma radiation on hard dental tissues of albino rats using scanning electron microscope – Part 1

    Microsoft Academic Search

    Nabil El-Faramawy; Reham Ameen; Khaled El-Haddad; Ahmed Maghraby; Medhat El-Zainy

    2011-01-01

    In the present study, 40 adult male albino rats were used to study the effect of gamma radiation on the hard dental tissues (enamel surface, dentinal tubules and the cementum surface). The rats were irradiated at 0.2, 0.5, 1.0, 2.0, 4.0 and 6.0 Gy gamma doses. The effects of irradiated hard dental tissues samples were investigated using a scanning electron microscope.

  6. 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.

  7. "PIN"-ning Down a Nonthermal Component in the Hard X-ray Emission of the Coma Cluster with Suzaku HXD/XIS and XMM-Newton Observations

    E-print Network

    Sarazin, Craig

    "PIN"-ning Down a Nonthermal Component in the Hard X-ray Emission of the Coma Cluster with Suzaku halo known resides in the Coma cluster of galaxies, which is also the X-ray brightest non-cooling core at hard X-ray energies. Thus far, claimed detections of this emission in the Coma cluster

  8. Hydrogenated amorphous silicon radiation detectors: Material parameters, radiation hardness, charge collection

    SciTech Connect

    Qureshi, S.

    1991-01-01

    For nearly two decades now hydrogenated amorphous silicon has generated considerable interest for its potential use in various device applications namely, solar cells, electrolithography, large-area electronics etc. The development of efficient and economic solar cells has been on the forefront of this research. This interest in hydrogenated amorphous silicon has been motivated by the fact that amorphous silicon can be deposited over a large area at relatively low cost compared to crystalline silicon. Hydrogenated amorphous silicon, frequently abbreviated as a-Si:H, used in solar-cell applications is a micron or less thick. The basic device structure is a p-i-n diode where the i layer is the active layer for radiation to interact. This is so because intrinsic a-Si:H has superior electrical properties in comparison to doped a-Si:H which serves the purpose of forming a potential barrier on either end of the i layer. The research presented in this dissertation was undertaken to study the properties of a-Si:H for radiation detection applications in physics and medicine.

  9. Recent advancements in the development of radiation hard semiconductor detectors for S-LHC

    NASA Astrophysics Data System (ADS)

    Fretwurst, E.; Adey, J.; Al-Ajili, A.; Alfieri, G.; Allport, P. P.; Artuso, M.; Assouak, S.; Avset, B. S.; Barabash, L.; Barcz, A.; Bates, R.; Biagi, S. F.; Bilei, G. M.; Bisello, D.; Blue, A.; Blumenau, A.; Boisvert, V.; Bolla, G.; Bondarenko, G.; Borchi, E.; Borrello, L.; Bortoletto, D.; Boscardin, M.; Bosisio, L.; Bowcock, T. J. V.; Brodbeck, T. J.; Broz, J.; Bruzzi, M.; Brzozowski, A.; Buda, M.; Buhmann, P.; Buttar, C.; Campabadal, F.; Campbell, D.; Candelori, A.; Casse, G.; Cavallini, A.; Charron, S.; Chilingarov, A.; Chren, D.; Cindro, V.; Collins, P.; Coluccia, R.; Contarato, D.; Coutinho, J.; Creanza, D.; Cunningham, L.; Dalla Betta, G.-F.; Dawson, I.; de Boer, W.; De Palma, M.; Demina, R.; Dervan, P.; Dittongo, S.; Dolezal, Z.; Dolgolenko, A.; Eberlein, T.; Eremin, V.; Fall, C.; Fasolo, F.; Ferbel, T.; Fizzotti, F.; Fleta, C.; Focardi, E.; Forton, E.; Garcia, C.; Garcia-Navarro, J. E.; Gaubas, E.; Genest, M.-H.; Gill, K. A.; Giolo, K.; Glaser, M.; Goessling, C.; Golovine, V.; González Sevilla, S.; Gorelov, I.; Goss, J.; Gouldwell Bates, A.; Grégoire, G.; Gregori, P.; Grigoriev, E.; Grillo, A. A.; Groza, A.; Guskov, J.; Haddad, L.; Härkönen, J.; Hauler, F.; Hoeferkamp, M.; Hönniger, F.; Horazdovsky, T.; Horisberger, R.; Horn, M.; Houdayer, A.; Hourahine, B.; Hughes, G.; Ilyashenko, I.; Irmscher, K.; Ivanov, A.; Jarasiunas, K.; Johansen, K. M. H.; Jones, B. K.; Jones, R.; Joram, C.; Jungermann, L.; Kalinina, E.; Kaminski, P.; Karpenko, A.; Karpov, A.; Kazlauskiene, V.; Kazukauskas, V.; Khivrich, V.; Khomenkov, V.; Kierstead, J.; Klaiber-Lodewigs, J.; Klingenberg, R.; Kodys, P.; Kohout, Z.; Korjenevski, S.; Koski, M.; Kozlowski, R.; Kozodaev, M.; Kramberger, G.; Krasel, O.; Kuznetsov, A.; Kwan, S.; Lagomarsino, S.; Lassila-Perini, K.; Lastovetsky, V.; Latino, G.; Lazanu, I.; Lazanu, S.; Lebedev, A.; Lebel, C.; Leinonen, K.; Leroy, C.; Li, Z.; Lindström, G.; Linhart, V.; Litovchenko, P.; Litovchenko, A.; Lo Giudice, A.; Lozano, M.; Luczynski, Z.; Luukka, P.; Macchiolo, A.; Makarenko, L. F.; Mandi?, I.; Manfredotti, C.; Manna, N.; Marti i Garcia, S.; Marunko, S.; Mathieson, K.; Melone, J.; Menichelli, D.; Messineo, A.; Metcalfe, J.; Miglio, S.; Mikuž, M.; Miyamoto, J.; Moll, M.; Monakhov, E.; Moscatelli, F.; Naoumov, D.; Nossarzewska-Orlowska, E.; Nysten, J.; Olivero, P.; Oshea, V.; Palviainen, T.; Paolini, C.; Parkes, C.; Passeri, D.; Pein, U.; Pellegrini, G.; Perera, L.; Petasecca, M.; Piemonte, C.; Pignatel, G. U.; Pinho, N.; Pintilie, I.; Pintilie, L.; Polivtsev, L.; Polozov, P.; Popa, A.; Popule, J.; Pospisil, S.; Pozza, A.; Radicci, V.; Rafí, J. M.; Rando, R.; Roeder, R.; Rohe, T.; Ronchin, S.; Rott, C.; Roy, A.; Ruzin, A.; Sadrozinski, H. F. W.; Sakalauskas, S.; Scaringella, M.; Schiavulli, L.; Schnetzer, S.; Schumm, B.; Sciortino, S.; Scorzoni, A.; Segneri, G.; Seidel, S.; Seiden, A.; Sellberg, G.; Sellin, P.; Sentenac, D.; Shipsey, I.; Sicho, P.; Sloan, T.; Solar, M.; Son, S.; Sopko, B.; Sopko, V.; Spencer, N.; Stahl, J.; Stolze, D.; Stone, R.; Storasta, J.; Strokan, N.; Sudzius, M.; Surma, B.; Suvorov, A.; Svensson, B. G.; Tipton, P.; Tomasek, M.; Tsvetkov, A.; Tuominen, E.; Tuovinen, E.; Tuuva, T.; Tylchin, M.; Uebersee, H.; Uher, J.; Ullán, M.; Vaitkus, J. V.; Velthuis, J.; Verbitskaya, E.; Vrba, V.; Wagner, G.; Wilhelm, I.; Worm, S.; Wright, V.; Wunstorf, R.; Yiuri, Y.; Zabierowski, P.; Zaluzhny, A.; Zavrtanik, M.; Zen, M.; Zhukov, V.; Zorzi, N.

    2005-10-01

    The proposed luminosity upgrade of the Large Hadron Collider (S-LHC) at CERN will demand the innermost layers of the vertex detectors to sustain fluences of about 10 16 hadrons/cm 2. Due to the high multiplicity of tracks, the required spatial resolution and the extremely harsh radiation field new detector concepts and semiconductor materials have to be explored for a possible solution of this challenge. The CERN RD50 collaboration "Development of Radiation Hard Semiconductor Devices for Very High Luminosity Colliders" has started in 2002 an R&D program for the development of detector technologies that will fulfill the requirements of the S-LHC. Different strategies are followed by RD50 to improve the radiation tolerance. These include the development of defect engineered silicon like Czochralski, epitaxial and oxygen-enriched silicon and of other semiconductor materials like SiC and GaN as well as extensive studies of the microscopic defects responsible for the degradation of irradiated sensors. Further, with 3D, Semi-3D and thin devices new detector concepts have been evaluated. These and other recent advancements of the RD50 collaboration are presented and discussed.

  10. The ionization processes in the Fe XXVII region of hot iron plasma in the field of hard gamma radiation

    NASA Astrophysics Data System (ADS)

    Illarionov, A. F.

    1989-06-01

    A highly ionized hot plasma of an Fe-56-type heavy element in the field of hard ionizing gamma radiation is studied. Processes of ionization and recombination are discussed for a plasma consisting of fully ionized Fe XXVII and hydrogen-like Fe XXVI ions in the case of a large optical depth of the plasma with respect to photoionization by gamma-ray quanta. An equation of ionization balance is presented for a plasma in the Fe XXVII region formed around a powerful source of hard gamma-ray radiation.

  11. 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.

  12. A radiation hard dipole magnet coils using aluminum clad copper conductors

    SciTech Connect

    Leonhardt, W.J.

    1989-01-01

    A C-type septum dipole magnet is located 600 mm downstream of the primary target in an external beam line of the AGS. Conventional use of fiber glass/epoxy electrical insulation for the magnet coils results in their failure after a relatively short running period, therefore a radiation hard insulation system is required. This is accomplished by replacing the existing copper conductor with a copper conductor having a thin aluminum skin which is anodized to provide the electrical insulation. Since the copper supports a current density of 59 A/mm/sup 2/, no reduction in cross sectional area can be tolerated. Design considerations, manufacturing techniques, and operating experience of a prototype dipole is presented. 3 refs., 4 figs.

  13. Optimization of radiation hardness and charge collection of edgeless silicon pixel sensors for photon science

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Tartarotti Maimone, D.; Pennicard, D.; Sarajlic, M.; Graafsma, H.

    2014-12-01

    Recent progress in active-edge technology of silicon sensors enables the development of large-area tiled silicon pixel detectors with small dead space between modules by utilizing edgeless sensors. Such technology has been proven in successful productions of ATLAS and Medipix-based silicon pixel sensors by a few foundries. However, the drawbacks of edgeless sensors are poor radiation hardness for ionizing radiation and non-uniform charge collection by edge pixels. In this work, the radiation hardness of edgeless sensors with different polarities has been investigated using Synopsys TCAD with X-ray radiation-damage parameters implemented. Results show that if no conventional guard ring is present, none of the current designs are able to achieve a high breakdown voltage (typically < 30 V) after irradiation to a dose of ~ 10 MGy. In addition, a charge-collection model has been developed and was used to calculate the charges collected by the edge pixels of edgeless sensors when illuminated with X-rays. The model takes into account the electric field distribution inside the pixel sensor, the absorption of X-rays, drift and diffusion of electrons and holes, charge sharing effects, and threshold settings in ASICs. It is found that the non-uniform charge collection of edge pixels is caused by the strong bending of the electric field and the non-uniformity depends on bias voltage, sensor thickness and distance from active edge to the last pixel (``edge space"). In particular, the last few pixels close to the active edge of the sensor are not sensitive to low-energy X-rays ( < 10 keV), especially for sensors with thicker Si and smaller edge space. The results from the model calculation have been compared to measurements and good agreement was obtained. The model can be used to optimize the edge design. From the edge optimization, it is found that in order to guarantee the sensitivity of the last few pixels to low-energy X-rays, the edge space should be kept at least 50% of the sensor thickness.

  14. 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.

  15. High Speed, Radiation Hard CMOS Pixel Sensors for Transmission Electron Microscopy

    NASA Astrophysics Data System (ADS)

    Contarato, Devis; Denes, Peter; Doering, Dionisio; Joseph, John; Krieger, Brad

    CMOS monolithic active pixel sensors are currently being established as the technology of choice for new generation digital imaging systems in Transmission Electron Microscopy (TEM). A careful sensor design that couples ?m-level pixel pitches with high frame rate readout and radiation hardness to very high electron doses enables the fabrication of direct electron detectors that are quickly revolutionizing high-resolution TEM imaging in material science and molecular biology. This paper will review the principal characteristics of this novel technology and its advantages over conventional, optically-coupled cameras, and retrace the sensor development driven by the Transmission Electron Aberration corrected Microscope (TEAM) project at the LBNL National Center for Electron Microscopy (NCEM), illustrating in particular the imaging capabilities enabled by single electron detection at high frame rate. Further, the presentation will report on the translation of the TEAM technology to a finer feature size process, resulting in a sensor with higher spatial resolution and superior radiation tolerance currently serving as the baseline for a commercial camera system.

  16. 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.

  17. 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.

  18. Radiation-hard ASICs for optical data transmission in the first phase of the LHC upgrade , P. Buchholzb

    E-print Network

    Gan, K. K.

    Radiation-hard ASICs for optical data transmission in the first phase of the LHC upgrade K.K. Gana Physik, Universität Siegen, Siegen, Germany We have designed two ASICs for possible applications for the first phase of the LHC luminosity upgrade. The ASICs include a high-speed driver for a VCSEL

  19. Bandwidths of Micro Twisted-Pair Cables and Fusion Spliced SIMM-GRIN Fiber and Radiation Hardness of PIN/VCSEL Arrays

    E-print Network

    Gan, K. K.

    factor. The increased data rate and radiation level will pose new challenges for a tracker situated closeBandwidths of Micro Twisted-Pair Cables and Fusion Spliced SIMM-GRIN Fiber and Radiation Hardness and the data acquisition system are transmitted via rad-hard SIMM fibers spliced to rad-tolerant GRIN fibers

  20. Bandwidths of micro twisted-pair cables and fusion spliced SIMM-GRIN fiber and radiation hardness of PIN/VCSEL arrays

    E-print Network

    Gan, K. K.

    factor. The increased data rate and radiation level will pose new challenges for a tracker situated closeBandwidths of micro twisted-pair cables and fusion spliced SIMM-GRIN fiber and radiation hardness and the data acquisition system are transmitted via rad-hard SIMM fibers spliced to rad-tolerant GRIN fibers

  1. Detection of a Spectral Break in the Extra Hard Component of GRB 090926A

    NASA Astrophysics Data System (ADS)

    Ackermann, M.; Ajello, M.; Asano, K.; 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.; Bonamente, E.; Borgland, A. W.; Bouvier, A.; Bregeon, J.; Brez, A.; Briggs, M. S.; Brigida, M.; Bruel, P.; Buehler, R.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caraveo, P. A.; Carrigan, S.; Casandjian, J. M.; Cecchi, C.; Çelik, Ö.; Chaplin, V.; Charles, E.; Chekhtman, A.; Chiang, J.; Ciprini, S.; Claus, R.; Cohen-Tanugi, J.; Connaughton, V.; Conrad, J.; Cutini, S.; Dermer, C. D.; de Angelis, A.; de Palma, F.; Dingus, B. L.; Silva, E. do Couto e.; Drell, P. S.; Dubois, R.; Favuzzi, C.; Fegan, S. J.; Ferrara, E. C.; Focke, W. B.; Frailis, M.; Fukazawa, Y.; Funk, S.; Fusco, P.; Gargano, F.; Gasparrini, D.; Gehrels, N.; Germani, S.; Giglietto, N.; Giordano, F.; Giroletti, M.; Glanzman, T.; Godfrey, G.; Goldstein, A.; Granot, J.; Greiner, J.; Grenier, I. A.; Grove, J. E.; Guiriec, S.; Hadasch, D.; Hanabata, Y.; Harding, A. K.; Hayashi, K.; Hayashida, M.; Hays, E.; Horan, D.; Hughes, R. E.; Itoh, R.; Jóhannesson, G.; Johnson, A. S.; Johnson, W. N.; Kamae, T.; Katagiri, H.; Kataoka, J.; Kippen, R. M.; Knödlseder, J.; Kocevski, D.; Kouveliotou, C.; Kuss, M.; Lande, J.; Latronico, L.; Lee, S.-H.; Llena Garde, M.; Longo, F.; Loparco, F.; Lovellette, M. N.; Lubrano, P.; Makeev, A.; Mazziotta, M. N.; McBreen, S.; McEnery, J. E.; McGlynn, S.; Meegan, C.; Mehault, J.; Mészáros, P.; Michelson, P. F.; Mizuno, T.; Monte, C.; Monzani, M. E.; Moretti, E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Nakajima, H.; Nakamori, T.; Naumann-Godo, M.; Nishino, S.; Nolan, P. L.; Norris, J. P.; Nuss, E.; Ohno, M.; Ohsugi, T.; Okumura, A.; 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.; Petrosian, V.; Piron, F.; Porter, T. A.; Preece, R.; Racusin, J. L.; Rainò, S.; Rando, R.; Rau, A.; Razzano, M.; Razzaque, S.; Reimer, A.; Reimer, O.; Reposeur, T.; Reyes, L. C.; Ripken, J.; Ritz, S.; 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.; Tanaka, T.; Tanaka, Y.; Thayer, J. B.; Thayer, J. G.; Tibaldo, L.; Tierney, D.; Toma, K.; Torres, D. F.; Tosti, G.; Tramacere, A.; Uchiyama, Y.; Uehara, T.; Usher, T. L.; Vandenbroucke, J.; 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.; Wood, K. S.; Wu, X. F.; Yamazaki, R.; Yang, Z.; Ylinen, T.; Ziegler, M.

    2011-03-01

    We report on the observation of the bright, long gamma-ray burst, GRB 090926A, by the Gamma-ray Burst Monitor and Large Area Telescope (LAT) instruments on board the Fermi Gamma-ray Space Telescope. GRB 090926A shares several features with other bright LAT bursts. In particular, it clearly shows a short spike in the light curve that is present in all detectors that see the burst, and this in turn suggests that there is a common region of emission across the entire Fermi energy range. In addition, while a separate high-energy power-law component has already been observed in other gamma-ray bursts, here we report for the first time the detection with good significance of a high-energy spectral break (or cutoff) in this power-law component around 1.4 GeV in the time-integrated spectrum. If the spectral break is caused by opacity to electron-positron pair production within the source, then this observation allows us to compute the bulk Lorentz factor for the outflow, rather than a lower limit.

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

    Microsoft Academic Search

    I. G. Akoev; S. S. Yurov; G. A. Leonteva; Yu. A. Livanova; A. H. Achmadieva; B. S. Fomenko; V. N. Lebedev; V. N. Lukanin

    1973-01-01

    From 15th plenary meeting; Madrid, Spain (10 May 1972). 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

  3. Radiation-Hard SpaceWire/Gigabit Ethernet-Compatible Transponder

    NASA Technical Reports Server (NTRS)

    Katzman, Vladimir

    2012-01-01

    A radiation-hard transponder was developed utilizing submicron/nanotechnology from IBM. The device consumes low power and has a low fabrication cost. This device utilizes a Plug-and-Play concept, and can be integrated into intra-satellite networks, supporting SpaceWire and Gigabit Ethernet I/O. A space-qualified, 100-pin package also was developed, allowing space-qualified (class K) transponders to be delivered within a six-month time frame. The novel, optical, radiation-tolerant transponder was implemented as a standalone board, containing the transponder ASIC (application specific integrated circuit) and optical module, with an FPGA (field-programmable gate array) friendly parallel interface. It features improved radiation tolerance; high-data-rate, low-power consumption; and advanced functionality. The transponder utilizes a patented current mode logic library of radiation-hardened-by-architecture cells. The transponder was developed, fabricated, and radhard tested up to 1 MRad. It was fabricated using 90-nm CMOS (complementary metal oxide semiconductor) 9 SF process from IBM, and incorporates full BIT circuitry, allowing a loop back test. The low-speed parallel LVCMOS (lowvoltage complementary metal oxide semiconductor) bus is compatible with Actel FPGA. The output LVDS (low-voltage differential signaling) interface operates up to 1.5 Gb/s. Built-in CDR (clock-data recovery) circuitry provides robust synchronization and incorporates two alarm signals such as synch loss and signal loss. The ultra-linear peak detector scheme allows on-line control of the amplitude of the input signal. Power consumption is less than 300 mW. The developed transponder with a 1.25 Gb/s serial data rate incorporates a 10-to-1 serializer with an internal clock multiplication unit and a 10-1 deserializer with internal clock and data recovery block, which can operate with 8B10B encoded signals. Three loop-back test modes are provided to facilitate the built-in-test functionality. The design is based on a proprietary library of differential current switching logic cells implemented in the standard 90-nm CMOS 9SF technology from IBM. The proprietary low-power LVDS physical interface is fully compatible with the SpaceWire standard, and can be directly connected to the SFP MSA (small form factor pluggable Multiple Source Agreement) optical transponder. The low-speed parallel interfaces are fully compatible with the standard 1.8 V CMOS input/output devices. The utilized proprietary annular CMOS layout structures provide TID tolerance above 1.2 MRad. The complete chip consumes less than 150 mW of power from a single 1.8-V positive supply source.

  4. Hard plastic cladding fiber (HPCF) based optical components for high speed short reach optical communications

    NASA Astrophysics Data System (ADS)

    Kim, Jun Ki; Kim, Dong Uk; Kim, Tae Young; Park, Chang Soo; Oh, Kyunghwan

    2006-09-01

    We developed the primary components applicable to HPCF links for short reach (SR) and very short reach (VSR) data communication systems. We fabricated 4x4 HPCF fused taper splitter, HPCF pigtailed VCSEL and PIN photodiode for high speed short reach communications and characterized back to back transmission performance of the link composed of these components by measuring eye diagrams and jitters. Adapting the fusion-tapering technique for glass optical fiber, we successfully fabricated a 4x4 HPCF fused taper coupler. The HPCF with a core diameter of 200?m and an outer diameter of 230?m had step refractive index of 1.45 and 1.40 for the core and the clad. The optimized fusion length and tapering waist which make minimum insertion loss of about 7dB and uniform output power splitting ratio with less than 0.5dB are 13mm and 150µm, respectively. As a light source for VSR networks, we chose a vertical cavity surface emitting laser (VCSEL) and developed a package with a HPCF pigtail. After positioning VCSEL and HPCF that made a minimum coupling loss, we glued the HPCF inside ceramic ferrule housing. In HPCF-PIN PD packaging, we added a micro polymer lens tip onto the HPCF ends to match the mode field area to the sensitive area of GaAs or InGaAs PIN PD. Coupling between a PIN PD chip and the lensed HPCF was optimized with the radius of curvature of 156µm with a low coupling loss of 0.3dB, which is compatible to conventional MMF-PD packaging. For 1.25 Gbps data rate, the eyes adequate to eye mask in gigabit Ethernet were wide open after all HPCF transmission link and no significant power penalty was observed.

  5. 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.

  6. Radiation-hard ASICs for optical data transmission in the first phase of the LHC upgrade

    E-print Network

    Gan, K K; Kagan, H P; Kass, R D; Moore, J R; Smith, D S; Wiese, A; Ziolkowskic, M; 10.1088/1748-0221/5/12/C12006

    2010-01-01

    We have designed two ASICs for possible applications in the optical links of a new layer of the pixel detector to be install inside the ATLAS Pixel detector for the first phase of the LHC luminosity upgrade. The ASICs include a high-speed driver for the VCSEL and a receiver/decoder to decode the signal received at the PIN diode to extract the data and clock. Both ASICs contain 4 channels for operation with a VCSEL or PIN array. The ASICs were designed using a 130 nm CMOS process to enhance the radiation-hardness. We have characterized the fabricated ASICs and the performance of the ASICs is satisfactory. The receiver/decoder can properly decode the bi-phase marked input stream with low PIN current and the driver can operate a VCSEL up to ~ 5 Gb/s. The added functionalities are also successful, including redundancy to bypass a broken VCSEL or PIN channel, individual control of VCSEL current, and power-on reset circuit to set all VCSEL currents to a nominal value. The ASICs were irradiated to a dose of 46 Mrad ...

  7. 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.

  8. 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.

  9. 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.

  10. Phase transitions in highly asymmetric binary hard-sphere fluids: Fluid-fluid binodal from a two-component mixture theory.

    PubMed

    Ayadim, A; Amokrane, S

    2006-08-01

    Fluid-fluid binodals of binary hard-sphere mixtures are computed from the recently proposed fundamental measure functional-mean spherical approximation closure of the two-component Ornstein-Zernike equation. The results, especially in the dense fluid region that was not accessible by previous theoretical methods, are compared with the corresponding ones for the one-component fluid of big spheres with effective potential obtained from the same closure. The general trends are those expected for hard-sphere potentials but small difference are detectable. The overall agreement found validates the equivalence of the two descriptions for size ratios R = 8.5 or greater. PMID:17025392

  11. 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.

  12. Development of cryogenic Si detectors by CERN RD39 Collaboration for ultra radiation hardness in SLHC environment

    Microsoft Academic Search

    Zheng Li; M. Abreu; P. Anbinderis; T. Anbinderis; N. D’Ambrosio; W. de Boer; E. Borchi; K. Borer; M. Bruzzi; S. Buontempo; W. Chen; V. Cindro; A. Dierlamm; V. Eremin; E. Gaubas; V. Gorbatenko; E. Grigoriev; F. Hauler; E. Heijne; S. Heising; O. Hempel; R. Herzog; J. Härkönen; I. Ilyashenko; S. Janos; L. Jungermann; V. Kalesinskas; J. Kapturauskas; R. Laiho; P. Luukka; I. Mandic; Rita De Masi; D. Menichelli; M. Mikuz; O. Militaru; T. O. Niinikosky; V. O’Shea; S. Pagano; S. Paul; K. Piotrzkowski; K. Pretzl; P. Rato Mendes; X. Rouby; G. Ruggiero; K. Smith; P. Sonderegger; P. Sousa; E. Tuominen; E. Tuovinen; E. Verbitskaya; J. Vaitkus; E. Wobst; M. Zavrtanik

    2007-01-01

    There are two key approaches in our CERN RD 39 Collaboration efforts to obtain ultra-radiation-hard Si detectors: (1) use of the charge\\/current injection to manipulate the detector internal electric field in such a way that it can be depleted at a modest bias voltage at cryogenic temperature range (?150K), and (2) freezing out of the trapping centers that affects the

  13. 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

  14. 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.

  15. 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.

  16. Soft and hard components of two-particle distributions on ($y_t,\\\\eta,\\\\phi$) from p-p collisions at $\\\\sqrt{s} = 200$ GeV

    Microsoft Academic Search

    R. J. Porter; T. A. Trainor

    2004-01-01

    We report measurements of large-scale two-particle correlations for 200 GeV p-p collisions on momentum components transverse rapidity $y_t$ (pion mass assigned), pseudorapidity $\\\\eta$ and azimuth angle $\\\\phi$. In both transverse $y_t \\\\otimes y_t$ and axial $(\\\\eta\\\\otimes\\\\eta,\\\\phi\\\\otimes\\\\phi) $ two-particle subspaces we observe two components of correlation structure (soft and hard) which we interpret respectively in terms of longitudinal string fragmentation and

  17. Seek control of hard disk drives based on final-state control taking account of the frequency components and the magnitude of control input

    Microsoft Academic Search

    Mitsuo Hirata; Tatsunori Hasegawa; Kenzo Nonami

    2002-01-01

    In this paper, the authors develop a new design method of the reference trajectory for hard disk drives. The control input is assumed to be generated through zero-order-hold and the reference trajectory is designed so that the frequency component of the control input is minimized over the desired frequency points. Input constraints can also be incorporated into the design. Simulation

  18. 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.

  19. Radiative decay Y(4260) -> X(3872) + gamma involving hadronic molecular and charmonium components

    E-print Network

    Yubing Dong; Amand Faessler; Thomas Gutsche; Valery E. Lyubovitskij

    2014-10-29

    We apply a phenomenological Lagrangian approach to the radiative decay Y(4260) -> X(3872) + gamma. The Y(4260) and X(3872) resonances are considered as composite states containing both molecular hadronic and charmonium components. Having a leading molecular component in the X(3872) and a sole molecular configuration for the Y(4260) results in a prediction compatible with present data.

  20. Radiation hardness of plastic scintillators for the Tile Calorimeter of the ATLAS detector

    NASA Astrophysics Data System (ADS)

    Jivan, H.; Mellado, B.; Sideras-Haddad, E.; Erasmus, R.; Liao, S.; Madhuku, M.; Peters, G.; Solvyanov, O.

    2015-06-01

    The radiation damage in polyvinyl toluene based plastic scintillator EJ200 obtained from ELJEN technology was investigated. This forms part of a comparative study conducted to aid in the upgrade of the Tile Calorimeter of the ATLAS detector during which the Gap scintillators will be replaced. Samples subjected to 6 MeV proton irradiation using the tandem accelerator of iThemba LABS, were irradiated with doses of approximately 0.8 MGy, 8 MGy, 25 MGy and 80 MGy. The optical properties were investigated using transmission spectroscopy whilst structural damage was assessed using Raman spectroscopy. Findings indicate that for the dose of 0.8 MGy, no structural damage occurs but a breakdown in the light transfer between base and fluor dopants is observed. For doses of 8 MGy to 80 MGy, structural damage leads to hydrogen loss in the benzene ring of the PVT base which forms free radicals. This results in an additional absorptive component causing increased transmission loss as dose is increased.

  1. 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.

  2. 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

  3. Radiation-Hard Optical Link for SLHC K.K. Gan, W. Fernando, H. Kagan, R. Kass, A. Law, S. Smith

    E-print Network

    Gan, K. K.

    of the Large Hadron Collider (LHC) by a factor of ten to 1035 cm-2 s-1 . Accordingly, the radiation level1 Radiation-Hard Optical Link for SLHC K.K. Gan, W. Fernando, H. Kagan, R. Kass, A. Law, S. Smith the feasibility of fabricating an optical link for the SLHC ATLAS silicon tracker based on the current pixel

  4. Radiation tolerance of opto-electronic components proposed for space-based quantum key distribution

    E-print Network

    Chuan, Tan Yue; Cheng, Cliff; Ling, Alexander

    2015-01-01

    Plasma in low earth orbit can damage electronic components and potentially jeopardise the scientific missions in space. Predicting the accumulated damage and understanding the components' radiation tolerance are important to mission planning. In this manuscript we report on the observed radiation tolerance of single photon detectors and a liquid crystal polarization rotator. We conclude that an uncooled Si APD could continue to operate from more than a month up to beyond the lifetime of the satellite depending on the orbit. The polarization rotator was also unaffected by the exposed dosage.

  5. Soft and hard components of two-particle distributions on ($y_t,\\\\eta,\\\\phi$) from p-p collisions at $\\\\sqrt{s} = 200$ GeV

    Microsoft Academic Search

    R. J. Porter; T. A. Trainor

    2004-01-01

    We report measurements of large-scale two-particle correlations for 200 GeV\\u000ap-p collisions on momentum components transverse rapidity $y_t$ (pion mass\\u000aassigned), pseudorapidity $\\\\eta$ and azimuth angle $\\\\phi$. In both transverse\\u000a$y_t \\\\otimes y_t$ and axial $(\\\\eta\\\\otimes\\\\eta,\\\\phi\\\\otimes\\\\phi) $ two-particle\\u000asubspaces we observe two components of correlation structure (soft and hard)\\u000awhich we interpret respectively in terms of longitudinal string fragmentation\\u000aand

  6. Fermi Observations of GRB 090510: A Short Hard Gamma-Ray Burst with an Additional, Hard Power-Law Component from 10 keV to GeV Energies

    E-print Network

    LAT, The Fermi

    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 is fit by the sum of a Band function with $\\Epeak = 3.9\\pm 0.3$\\,MeV, which is the highest yet measured, and a hard power-law component with photon index $-1.62\\pm 0.03$ that dominates the emission below $\\approx$\\,20\\,keV and above $\\approx$\\,100\\,MeV. The onset of the high-energy spectral component appears to be delayed by $\\sim$\\,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. Observ...

  7. 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.

  8. 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

  9. Radiation-hard analog-to-digital converters for space and strategic applications

    NASA Technical Reports Server (NTRS)

    Gauthier, M. K.; Dantas, A. R. V.

    1985-01-01

    During the course of the Jet Propulsion Laboratory's program to study radiation-hardened analog-to-digital converters (ADCs), numerous milestones have been reached in manufacturers' awareness and technology development and transfer, as well as in user awareness of these developments. The testing of ADCs has also continued with twenty different ADCs from seven manufacturers, all tested for total radiation dose and three tested for neutron effects. Results from these tests are reported.

  10. Radiation hardness of plastic scintillating fiber against fast neutron and gamma -ray irradiation

    Microsoft Academic Search

    Akira Murakami; Hideki Yoshinaka; Minehiko Goto

    1993-01-01

    In future collider experiments, where a background radiation level is estimated to be very high, e.g. around 10[sup 2] [approximately] 10[sup 5] Gy\\/yr and 10[sup 11] [approximately] 10[sup 14] n\\/cm[sup 2]\\/yr at SSC, the detectors operating around the collision point in the experiments will encounter a considerable amount of radiation. Therefore, the detectors, especially the calorimeter, are required to be

  11. Radiation hardness of a wide-bandgap material by the example of SiC nuclear radiation detectors

    NASA Astrophysics Data System (ADS)

    Ivanov, A. M.; Strokan, N. B.; Lebedev, A. A.

    2012-05-01

    A polarization effect characteristically occurs in detectors based on wide-bandgap materials at considerable concentrations of radiation defects. The appearance of an electromotive force in the bulk of a detector is due to the long-term capture of carriers at deep levels related to radiation centers. The kinetics and strength of the polarization field have been determined. The carrier capture by the radiation centers can be controlled by varying the detector temperature, with a compromise reached at the "optimal" temperature between the generation current and the position of the deepest of the levels whose contribution to the loss of charge via capture is negligible. It has been found that the depth of a level of this kind (related to the energy gap width) is close to 1/3, irrespective of a material. The optimal temperatures are strictly individual for materials.

  12. Influence of surface treatment of components on thermal radiation performance in infrared optical systems

    NASA Astrophysics Data System (ADS)

    Luo, Wen-fei; Wu, Jian-peng; Peng, Jia-qi; Zhang, Bin

    2014-09-01

    The existence of self-generated thermal radiation in infrared optical systems exhibits a great impact to the extraction of target signal and further degrades the signal-to-noise ratio (SNR), thus making the self-generated thermal radiation one of the important factors affecting the detective property. In this paper, a refraction-reflection optical system has been taken as an example and the three-dimensional simulation model has been built up using the ASAP optical analysis software. On this basis, the influence of the surface roughness, the level of the optics contaminated by the particles with the uniform and non-uniform distributions, the treatment of the mechanical surface (such as blacking, polishing, roughening) on the self-generated thermal radiation have been focused on discussion. Moreover, the thermal radiation of the system has been evaluated by the effective emissivity. The results indicate that the effective emissivity varies with different surface treatment. The self-generated thermal radiation is more and more serious with the increasing of the effective emissivity, resulting in great difficulty in obtaining and analyzing the target signal. It follows that the surface treatment of components exhibits a significant effect on the stray radiation performance in infrared optical systems. Consequently, appropriate treatments should be taken to diminish the self-generated thermal radiation in order to meet the requirements of the stray radiation performance in practical applications.

  13. 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.

  14. 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.

  15. 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.

  16. Electronegativities in situ, bond hardnesses, and charge-transfer components of bond energies from the topological theory of atoms in molecules

    SciTech Connect

    Cioslowski, J.; Mixon, S.T. (Florida State Univ., Tallahassee (United States))

    1993-02-10

    Rigorous definitions for electronegativities of atoms and functional groups in molecules, bond hardnesses, and the charge-transfer components of the bond energies are proposed. The definitions rely upon values of total energies and their derivatives calculated for molecules composed of fragments with a controlled degree of charge transfer. Such calculations, in which the atomic or fragment charges are obtained with the help of the topological theory of atoms in molecules, are easily accomplished by adding appropriate Lagrange multiplier terms to the electronic Hamiltonian. Numerical examples that are given for 23 different systems indicate that the bond hardnesses are mostly transferable, but because of the electric field generated by the molecular environment the electronegativity differences are not. 27 refs., 1 fig., 1 tab.

  17. 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.

  18. Radiation Protection lessonsRadiation Protection lessons Experiences with operating beams for

    E-print Network

    McDonald, Kirk

    Radiation Protection lessonsRadiation Protection lessons Experiences with operating beams, they are exposed to much lower radiation than compared to a storage location in the target chamberchamber. WANF O'rings in pumps and motors were not specified to be radiation resistant. CNGSCNGS only radiation hard components

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

    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 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.

  20. Centrality dependences of soft and hard components of pt distributions of negative pions in 4He+12C collisions at 4.2A GeV/c

    NASA Astrophysics Data System (ADS)

    Olimov, Khusniddin K.; Iqbal, Akhtar; Lutpullaev, Sagdulla L.; Hadi, Sayyed A.; Glagolev, Viktor V.; Yuldashev, B. S.; Haseeb, Mahnaz Q.

    2015-05-01

    The dependences of the shapes of transverse momentum distributions of the negative pions, produced in minimum bias 4He+12C collisions at a momentum of 4.2 GeV/c per nucleon, on collision centrality and fitting range of pt were analyzed systematically. To study the change in slopes (temperatures) of the pt spectra of ?- with changing collision centrality and fitting pt range, the pt spectra, extracted from the experimental data and quark-gluon string model (QGSM) calculations, were fitted by the one- and two-temperature Hagedorn and Boltzmann functions. Fitting of the experimental pt distributions of ?- in both the whole pt and pt = 0.1-1.2 GeV/c intervals required the two-temperature functions for adequate description of spectra, in agreement with the previous findings for different sets of colliding nuclei and various energies. On the whole, the absolute values of the extracted temperatures were lower in case of fitting range pt = 0.1-0.7 GeV/c as compared to the fitting interval pt = 0.1-1.2 GeV/c. The one-temperature functions were sufficient for fitting satisfactorily the experimental pt distributions of the negative pions in range pt = 0.1-0.7 GeV/c. In contrast to the experimental temperatures, the extracted QGSM temperatures were not sensitive to collision centrality and fitting range of pt. The collision centrality dependences of the temperatures of soft (pt = 0.1-0.5 GeV/c) and hard (pt = 0.5-1.2 GeV/c) components of the experimental pt distributions of the negative pions in 4He+12C collisions at 4.2A GeV/c were studied separately. The extracted temperatures of both soft and hard components of pt distributions of ?- depended on geometry (size) and degree of overlap of colliding nuclei in peripheral, semicentral and central 4He+12C collisions. The temperature of soft pt component of the negative pions was consistently larger in semicentral and central 4He+12C collisions than that in peripheral interactions. The temperature of hard pt component of ?- in 4He+12C collisions decreased consistently with an increase in collision centrality. The physical interpretations of the observed centrality dependences of temperature (T) of soft and hard pt components of the negative pions in 4He+12C collisions were given.

  1. Space radiation shielding studies for astronaut and electronic component risk assessment

    NASA Astrophysics Data System (ADS)

    Fuchs, Jordan; Gersey, Brad; Wilkins, Richard

    The space radiation environment is comprised of a complex and variable mix of high energy charged particles, gamma rays and other exotic species. Elements of this radiation field may also interact with intervening matter (such as a spaceship wall) and create secondary radiation particles such as neutrons. Some of the components of the space radiation environment are highly penetrating and can cause adverse effects in humans and electronic components aboard spacecraft. Developing and testing materials capable of providing effective shielding against the space radiation environment presents special challenges to researchers. Researchers at the Cen-ter for Radiation Engineering and Science for Space Exploration (CRESSE) at Prairie View AM University (PVAMU) perform accelerator based experiments testing the effectiveness of various materials for use as space radiation shields. These experiments take place at the NASA Space Radiation Laboratory at Brookhaven National Laboratory, the proton synchrotron at Loma Linda University Medical Center, and the Los Alamos Neutron Science Center at Los Alamos National Laboratory where charged particles and neutrons are produced at energies similar to those found in the space radiation environment. The work presented in this paper constitutes the beginning phase of an undergraduate research project created to contribute to this ongoing space radiation shielding project. Specifically, this student project entails devel-oping and maintaining a database of information concerning the historical data from shielding experiments along with a systematic categorization and storage system for the actual shielding materials. The shielding materials referred to here range in composition from standard materi-als such as high density polyethylene and aluminum to exotic multifunctional materials such as spectra-fiber infused composites. The categorization process for each material includes deter-mination of the density thickness of individual samples and a clear labeling and filing method that allows immediate cross referencing with other material samples during the experimental design process. Density thickness measurements will be performed using a precision scale that will allow for the fabrication of sets of standard density thicknesses of selected materials for ready use in shielding experiments. The historical data from previous shielding experiments consists primarily of measurements of absorbed dose, dose equivalent and dose distributions from a Tissue Equivalent Proportional Counter (TEPC) as measured downstream of various thicknesses of the materials while being irradiated in one of the aforementioned particle beams. This data has been digitally stored and linked to the composition of each material and may be easily accessed for shielding effectiveness inter-comparisons. This work was designed to facili-tate and increase the efficiency of ongoing space radiation shielding research performed at the CRESSE as well as serve as a way to educate new generations of space radiation researchers.

  2. Principal component-based radiative transfer model for hyperspectral sensors: theoretical concept.

    PubMed

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

    2006-01-01

    Modern infrared satellite sensors such as the Atmospheric Infrared Sounder (AIRS), the Cross-Track Infrared Sounder (CrIS), the Tropospheric Emission Spectrometer (TES), the Geosynchronous Imaging Fourier Transform Spectrometer (GIFTS), and the 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, superfast radiative transfer models are needed. We present 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 the properties of PC scores and instrument line-shape functions. The PCRTM is accurate and flexible. Because of its high speed and compressed spectral information format, it has great potential for superfast one-dimensional physical retrieval and for numerical weather prediction large volume radiance data assimilation applications. The model has been successfully developed for the 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. PMID:16422339

  3. Concept of Double Peak electric field distribution in the development of radiation hard silicon detectors

    Microsoft Academic Search

    E. Verbitskaya; V. Eremin; Z. Li; J. Härkönen; M. Bruzzi

    2007-01-01

    The concept of Double Peak (DP) electric field distribution is considered for the analysis of operational characteristics of irradiated silicon detectors. The key point of the model is trapping of equilibrium carriers to the midgap energy levels of radiation-induced defects, which leads to a non-uniform distribution of space charge concentration with positively and negatively charged regions adjacent to the p+

  4. Separation of hard x-ray synchrotron radiation from electron beam slices

    NASA Astrophysics Data System (ADS)

    He, A.; Chubar, O.; Yu, L. H.

    2014-09-01

    In the electron beam slicing scheme1, 2 considered for National Synchrotron Light Source II (NSLS-II) at Brookhaven National Laboratory, when a low energy electron bunch crosses from top of a high energy storage ring electron bunch, its coulomb force will kick a short slice (slicing bunch) from the core (core bunch) of the storage ring electron bunch. The short slice bunch and the long core bunch when passing through the 3 m long U20 in-vacuum undulator will radiate X-ray pulses with pulse length ~150 fs and 30 ps respectively. To separate the satellite radiation from the core radiation, we propose a conceptual optical scheme allowing for the separation. To get reliable estimates of the separation performances, we apply the Synchrotron Radiation Workshop (SRW) physical optics computer code3, 4 to study the wavefront propagation. As calculations show, at 7.8 keV, the separation signal-to-noise ratio can reach 5~12 and the satellite photon flux per pulse at sample can be 5000~20000 photons/0.1%BW with x-ray pulse length 150 ~ 330 fs depending on the separation method and the crossing angle between the low energy electron bunch and the high energy storage ring bunch. Since the repetition rate of the electron beam slicing system can reach 100 kHz, the average flux per second can reach 5 x 108 ` 2 x 109 photons/sec/0.1%BW.

  5. 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.

  6. Reduction of a collisional-radiative mechanism for argon plasma based on principal component analysis

    NASA Astrophysics Data System (ADS)

    Bellemans, A.; Munafò, A.; Magin, T. E.; Degrez, G.; Parente, A.

    2015-06-01

    This article considers the development of reduced chemistry models for argon plasmas using Principal Component Analysis (PCA) based methods. Starting from an electronic specific Collisional-Radiative model, a reduction of the variable set (i.e., mass fractions and temperatures) is proposed by projecting the full set on a reduced basis made up of its principal components. Thus, the flow governing equations are only solved for the principal components. The proposed approach originates from the combustion community, where Manifold Generated Principal Component Analysis (MG-PCA) has been developed as a successful reduction technique. Applications consider ionizing shock waves in argon. The results obtained show that the use of the MG-PCA technique enables for a substantial reduction of the computational time.

  7. 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.

  8. Radiation interlocks: The choice between conventional hard-wired logic and computer-based systems

    SciTech Connect

    Crook, K.F.

    1986-11-01

    During the past few years, the use of computers in radiation safety systems has become more widespread. This is not surprising given the ubiquitous nature of computers in the modern technological world. But is a computer a good choice for the central logic element of a personnel safety system. Recent accidents at computer controlled medical accelerators would indicate that extreme care must be exercised if malfunctions are to be avoided. The Department of Energy has recently established a sub-committee to formulate recommendations on the use of computers in safety systems for accelerators. This paper will review the status of the committee's recommendations, and describe radiation protection interlock systems as applied to both accelerators and to irradiation facilities. Comparisons are made between the conventional relay approach and designs using computers. 6 refs., 6 figs.

  9. Recent advancements in the development of radiation hard semiconductor detectors for S-LHC

    Microsoft Academic Search

    E. Fretwurst; J. Adey; A. Al-Ajili; G. Alfieri; P. P. Allport; M. Artuso; S. Assouak; B. S. Avset; L. Barabashi; A. Barcz; R. Bates; S. F. Biagi; G. M. Bilei; D. Bisello; A. Blue; A. Blumenau; V. Boisvert; G. Bolla; G. Bondarenko; E. Borchi; L. Borrello; D. Bortoletto; M. Boscardin; L. Bosisio; T. J. V. Bowcock; T. J. Brodbeck; J. Broz; M. Bruzzi; A. Brzozowski; M. Buda; P. Buhmann; C. Buttar; F. Campabadal; D. Campbell; A. Candelori; G. Casse; A. Cavallini; S. Charron; A. Chilingarov; D. Chren; V. Cindro; P. Collins; R. Coluccia; D. Contarato; J. Coutinho; D. Creanza; L. Cunningham; G.-F. Dalla Betta; I. Dawson; W. de Boer; M. De Palma; R. Demina; P. Dervan; S. Dittongo; Z. Dolezal; A. Dolgolenko; T. Eberlein; V. Eremin; C. Fall; F. Fasolo; T. Ferbel; F. Fizzotti; C. Fleta; E. Focardi; E. Forton; C. Garcia; J. E. Garcia-Navarro; E. Gaubas; M.-H. Genest; K. A. Gill; K. Giolo; M. Glaser; C. Goessling; V. Golovine; S. González Sevilla; I. Gorelov; J. Goss; A. Gouldwell Bates; G. Grégoire; P. Gregori; E. Grigoriev; A. A. Grillo; A. Groza; J. Guskov; L. Haddad; J. Härkönen; F. Hauler; M. Hoeferkamp; F. Hönniger; T. Horazdovsky; R. Horisberger; M. Horn; A. Houdayer; B. Hourahine; G. Hughes; I. Ilyashenko; K. Irmscher; A. Ivanov; K. Jarasiunas; K. M. H. Johansen; B. K. Jones; R. Jones; C. Joram; L. Jungermann; E. Kalinina; P. Kaminski; A. Karpenko; A. Karpov; V. Kazlauskiene; V. Kazukauskas; V. Khivrich; V. Khomenkov; J. Kierstead; J. Klaiber-Lodewigs; R. Klingenberg; P. Kodys; Z. Kohout; S. Korjenevski; M. Koski; R. Kozlowski; M. Kozodaev; G. Kramberger; O. Krasel; A. Kuznetsov; S. Kwan; S. Lagomarsino; K. Lassila-Perini; V. Lastovetsky; G. Latino; I. Lazanu; S. Lazanu; A. Lebedev; C. Lebel; K. Leinonen; C. Leroy; Z. Li; G. Lindström; V. Linhart; P. Litovchenko; A. Litovchenko; A. Lo Giudice; M. Lozano; Z. Luczynski; P. Luukka; A. Macchiolo; L. F. Makarenko; I. Mandi?; C. Manfredotti; N. Manna; S. Marti i Garcia; S. Marunko; K. Mathieson; J. Melone; D. Menichelli; A. Messineo; J. Metcalfe; S. Miglio; M. Mikuz; J. Miyamoto; M. Moll; E. Monakhov; F. Moscatelli; D. Naoumov; E. Nossarzewska-Orlowska; J. Nysten; P. Olivero; V. Oshea; T. Palviainen; C. Paolini; C. Parkes; D. Passeri; U. Pein; G. Pellegrini; L. Perera; M. Petasecca; C. Piemonte; G. U. Pignatel; N. Pinho; I. Pintilie; L. Pintilie; L. Polivtsev; P. Polozov; A. Popa; J. Popule; S. Pospisil; A. Pozza; V. Radicci; J. M. Rafí; R. Rando; R. Roeder; T. Rohe; S. Ronchin; C. Rott; A. Roy; A. Ruzin; H. F. W. Sadrozinski; S. Sakalauskas; M. Scaringella; L. Schiavulli; S. Schnetzer; B. Schumm; S. Sciortino; A. Scorzoni; G. Segneri; S. Seidel; A. Seiden; G. Sellberg; P. Sellin; D. Sentenac; I. Shipsey; P. Sicho; T. Sloan; M. Solar; S. Son; B. Sopko; V. Sopko; N. Spencer; J. Stahl; D. Stolze; R. Stone; J. Storasta; N. Strokan; M. Sudzius; B. Surma; A. Suvorov; B. G. Svensson; P. Tipton; M. Tomasek; A. Tsvetkov; E. Tuominen; E. Tuovinen; T. Tuuva; M. Tylchin; H. Uebersee; J. Uher; M. Ullán; J. V. Vaitkus; J. Velthuis; E. Verbitskaya; V. Vrba; G. Wagner; I. Wilhelm; S. Worm; V. Wright; R. Wunstorf; Y. Yiuri; P. Zabierowski; A. Zaluzhny; M. Zavrtanik; M. Zen; V. Zhukov; N. Zorzi

    2005-01-01

    The proposed luminosity upgrade of the Large Hadron Collider (S-LHC) at CERN will demand the innermost layers of the vertex detectors to sustain fluences of about 1016 hadrons\\/cm2. Due to the high multiplicity of tracks, the required spatial resolution and the extremely harsh radiation field new detector concepts and semiconductor materials have to be explored for a possible solution of

  10. Design of radiation hard CMOS APS image sensors in a 0.35-um standard process

    Microsoft Academic Search

    El-Sayed I. Eid; Tony Y. Chan; Eric R. Fossum; Richard H. Tsai; Robert Spagnuolo; John J. Deily

    2001-01-01

    A CMOS APS Image sensor test chip was designed employing the physical design techniques of enclosed geometry and guard ring, and according to the design rules of a 0.35-micrometers CMOS standard process that has a gate oxide thickness of approximately 7.0 nm. Three sets of radiation tolerant photodiode active pixels were developed employing these design techniques. They are N-type, and

  11. Microclimate of a desert playa: evaluation of annual radiation, energy, and water budgets components

    Microsoft Academic Search

    Esmaiel Malek

    2003-01-01

    We set up two automatic weather stations over a playa (the flat floor of an undrained desert basin that, at times, becomes a shallow lake), approximately 65 km east-west by 130 km north-south, located in Dugway (40° 08N, 113° 27W, 1124 m above mean sea level) in northwestern Utah, USA, in 1999. These stations measured the radiation budget components, namely:

  12. 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

  13. Statistical process control for QML (Qualified Manufacturer's List) radiation hardness assurance

    Microsoft Academic Search

    P. S. Winokur; F. W. Sexton; D. M. Fleetwood; J. R. Schwank; M. R. Shaneyfelt; M. D. Terry

    1990-01-01

    Effective testing of highly-complex VLSI circuits employing ever decreasing feature sizes is becoming extremely difficult. This difficulty arises from the inability to routinely provide 100% fault coverage during testing of these complex functions, as well as by a scarcity of functional parts inherent in low-volume\\/high-product-mix military-component manufacturing lines. Under the sponsorship of RADC and DESC, the government has proposed a

  14. EU contract number RII3-CT-2003-506395 CARE-Note-07-004-SRF Radiation hardness tests of piezoelectric actuators with fast neutrons at liquid helium

    E-print Network

    Paris-Sud XI, Université de

    EU contract number RII3-CT-2003-506395 CARE-Note-07-004-SRF SRF Radiation hardness tests RII3-CT-2003-506395 CARE-Note-07-004-SRF Introduction Motorized Fast Active Cold Tuning System (FACTS frequency in SRF cavities of various projects and Test facilities (e.g., TESLA [1], Test Facility (TTF) [2

  15. 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.

    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* John H. Scofield Department of Physics, Oberlin College Oberlin, OH 44074 and D.M. Fleetwood Sandia National Laboratories Albuquerque, NM

  16. Radiation hardness measurements of new permanent magnet materials for high-intensity linac applications

    SciTech Connect

    Barlow, D.B.; Kraus, R.H.; Borden, M.J.

    1998-12-31

    This is the final report of a two-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The radiation resistance of samples of high-strength samarium cobalt permanent-magnet material has been studied. Samples of commercially available material were obtained from four different manufacturers. The remanent field of the samples was measured before and after the samples were irradiated with neutrons produced at the beam stop of the Los Alamos Neutron Science Center (LANSCE) proton accelerator.

  17. 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.

  18. 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.

  19. Radiation Hard Silicon for Medical, Space and High Energy Physics Applications

    SciTech Connect

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

    2009-02-24

    The objective of this paper is to give an overview on how silicon particle detector would survive operational in extremely harsh radiation environment after luminosity upgrade of the CERN LHC (Large Hadron Collider). The Super-LHC would result in an integrated fluence 1 x 10{sup 16} p/cm{sup 2} and that is well beyond the radiation tolerance of even the most advanced semiconductor detectors fabricated by commonly adopted technologies. The Czochralski silicon (Cz-Si) has intrinsically high oxygen concentration. Therefore Cz-Si is considered as a promising material for the tracking systems in future very high luminosity colliders. The fabrication process issues of Cz-Si are discussed and the formation of thermal donors is especially emphasized. N{sup +}/p{sup -}/p{sup +} and p{sup +}/n{sup -}/n{sup +} detectors have been processed on magnetic Czochralski (MCz-Si) wafers. We show measurement data of AC-coupled strip detectors and single pad detectors as well as experimental results of intentional TD doping. Data of spatial homogeneity of electrical properties, full depletion voltage and leakage current, is shown and n and p-type devices are compared. Our results show that it is possible to manufacture high quality n{sup +}/p{sup -}/p{sup +} and p{sup +}/n{sup -}/n{sup +} particle detectors from high resistivity Czochralski silicon.

  20. Radiation-hard ASICs for optical data transmission in the ATLAS pixel detector K.K. Gan, K.E. Arms, M. Johnson, H. Kagan, R. Kass, C. Rush, S. Smith,

    E-print Network

    Gan, K. K.

    Radiation-hard ASICs for optical data transmission in the ATLAS pixel detector K.K. Gan, K.E. Arms Fachbereich Physik, Universitaet Siegen, 57068 Siegen, Germany We have developed two radiation-hard ASICs have successfully implemented both ASICs in 0.25 µm CMOS technology using enclosed layout transistors

  1. Radiation-hard ASICs for optical data transmission in the ATLAS pixel detector K.K. Gan, K.E. Arms, M. Johnson, H. Kagan, R. Kass, C. Rush, S. Smith,

    E-print Network

    Gan, K. K.

    Radiation-hard ASICs for optical data transmission in the ATLAS pixel detector K.K. Gan, K.E. Arms Fachbereich Physik, Universitaet Siegen, 57068 Siegen, Germany We have developed two radiation-hard ASICs have successfully implemented both ASICs in 0.25 mm CMOS technology using enclosed layout transistors

  2. Microclimate of a desert playa: evaluation of annual radiation, energy, and water budgets components

    NASA Astrophysics Data System (ADS)

    Malek, Esmaiel

    2003-03-01

    We set up two automatic weather stations over a playa (the flat floor of an undrained desert basin that, at times, becomes a shallow lake), approximately 65 km east-west by 130 km north-south, located in Dugway (40° 08N, 113° 27W, 1124 m above mean sea level) in northwestern Utah, USA, in 1999. These stations measured the radiation budget components, namely: incoming Rsi and outgoing Rso solar or shortwave radiation, using two Kipp and Zonen pyranometers (one inverted), the incoming Rli (or atmospheric) and outgoing Rlo (or terrestrial) longwave radiation, using two Kipp and Zonen pyrgeometers (one inverted) during the year 2000. These sensors were ventilated throughout the year to prevent dew and frost formation. Summation of these components yields the net radiation Rn. We also measured the air temperatures and humidity at 1 and 2 m and the soil moisture and temperature (Campbell Sci., Inc., CSI) to evaluate the energy budget components (latent (LE), sensible (H), and the soil (Gsur) heat fluxes). The 10 m wind speed U10 and direction (R.M. Young wind monitor), precipitation (CSI), and the surface temperature (Radiation and Energy Balance Systems, REBS) were also measured during 2000. The measurements were taken every 2 s, averaged into 20 min, continuously, throughout the year 2000. The annual comparison of radiation budget components indicates that about 34% of the annual Rsi (6937.7 MJ m-2 year-1) was reflected back to the sky as Rso, with Rli and Rlo amounting to 9943.4 MJ m-2 year-1 and 12 789.7 MJ m-2 year-1 respectively. This yields about 1634.3 MJ m-2 year-1 as Rn, which is about 24% of the annual Rsi. Of the total 1634.3 MJ m-2 year-1 available energy, about 25% was used for the process of evaporation (LE) and 77% for heating the air (H). The annual heat contribution from the soil to the energy budget amounted to 2% during the experimental period. Our studies showed that the total annual measured precipitation amounted to 108.0 mm year-1 during the year 2000, but the total evaporation was 167.6 mm year-1, which means some water was extracted from the shallow water table (about 60 cm on the average depth during the year 2000).

  3. 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.

  4. Artificial diamonds as radiation-hard detectors for ultra-fast fission-fragment timing

    NASA Astrophysics Data System (ADS)

    Oberstedt, S.; Borcea, R.; Bry?, T.; Gamboni, Th.; Geerts, W.; Hambsch, F.-J.; Oberstedt, A.; Vidali, M.

    2013-06-01

    In the framework of the construction of the double time-of-flight spectrometer VERDI, where we aim at measuring pre- and post-neutron masses directly and simultaneously, ultra-fast time pick-up detectors based on artificial diamond material were investigated for the first time with fission fragments from 252Cf (0.5 MeV/uradiation fluence was determined up to at least 109 fission-fragments/cm2 together with more than 3.5×109 neutrons/cm2 and 3×1010?-particles/cm2. This fluence is characteristic for fission experiments. The pre-requisite for the observed signal stability is the application of priming of the diamond material with a strong ?-source for about 48 h. The intrinsic timing resolution of a 100 ?m thick polycrystalline CVD diamond detector with a size of 1×1 cm2 was determined to ?int=(283±41) ps by comparison with Monte-Carlo simulations. Using broadband pre-amplifiers, 4-fold segmented detectors of same total size and with a thickness of 180 ?m show an intrinsic timing resolution of ?int=(106±21) ps. This is highly competitive with the best micro-channel plate detectors. Due to the limited and batch-dependent charge collection efficiency of poly-crystalline diamond material, the detection efficiency for fission fragments may be smaller than 100%.

  5. Thin foil Faraday collectors as a radiation hard fast lost-ion diagnostic

    NASA Astrophysics Data System (ADS)

    Cecil, F. E.; Aakhus-Witt, A.; Hawbaker, J.; Sayers, J.; Bozek, A.; Heidbrink, W. W.; Darrow, D. S.; Debey, T. M.; Marmar, E.

    2003-03-01

    We are investigating thin foil Faraday collectors as a diagnostic for lost fast ions from tokamak fusion plasmas. Prototype devices have been recently installed in the National Spherical Torus Experiment and DIII-D. Initial results from these devices indicate a loss of energetic ions from a variety of plasma conditions. Results from a device installed immediately outside a thin Be window on ALCATOR C-mod, as a test on the response to moderately intense fluxes of soft x rays indicate an upper limit of about 2×10-22 A/photon/cm2 at a plasma electron temperature of 1.8 keV. An important property of the diagnostic is the expected ability to operate under fairly high neutron/gamma radiation backgrounds. We have tested this expectation by measuring the current from a thin (2.5 ?m) Ni foil placed in the core of a TRIGA fission reactor. At a maximum steady-state power of 950 kW (1013 n/cm2/s), a current of 1.2 nA/cm2 was measured.

  6. Radiation hard blocked tunneling band {GaAs}/{AlGaAs} superlattice long wavelength infrared detectors

    NASA Astrophysics Data System (ADS)

    Wu, C. S.; Wen, C. P.; Reiner, P.; Tu, C. W.; Hou, H. Q.

    1996-09-01

    We have developed a novel multiple quantum well (MQW) long wavelength infrared (LWIR) detector which can operate in a photovoltaic detection mode with an intrinsic event discrimination (IED) capability. The detector was constructed using the {GaAs}/{AlGaAs} MQW technology to form a blocked tunneling band superlattice structure with a 10.2 micron wavelength and 2.2 micron bandwidth. The detector exhibited Schottky junction and photovoltaic detection characteristics with extremely low dark current and low noise as a result of a built-in tunneling current blocking layer structure. In order to enhance quantum efficiency, a built-in electric field was created by grading the doping concentration of each quantum well in the MQW region. The peak responsivity of the detector was 0.4 amps/W with a measured detectivity of 6.0 × 10 11 Jones. The external quantum efficiency was measured to be 4.4%. The detector demonstrated an excellent intrinsic event discrimination capability due to the presence of a p-type GaAs hole collector layer, which was grown on top of the n-type electron emitter region of the MQW detector. The best results show that an infrared signal which is as much as 100 times smaller than coincident nuclear radiation induced current can be distinguished and extracted from the noise signal. With this hole collector structure, our detector also demonstrated two-color detection.

  7. The GBTIA, a 5 Gbit/s Radiation-Hard Optical Receiver for the SLHC Upgrades

    E-print Network

    Menouni, M; Moreira, P

    2009-01-01

    The GigaBit Transceiver (GBT) is a high-speed optical transmission system currently under development for HEP applications. This system will implement bi-directional optical links to be used in the radiation environment of the Super LHC. The GigaBit Transimpedance Amplifier (GBTIA) is the front-end optical receiver of the GBT chip set. This paper presents the GBTIA, a 5 Gbit/s, fully differential, and highly sensitive optical receiver designed and implemented in a commercial 0.13 ?m CMOS process. When connected to a PIN-diode, the GBTIA displays a sensitivity better than ?19 dBm for a BER of 10?12. The differential output across an external 50 ? load remains constant at 400 mVpp even for signals near the sensitivity limit. The chip achieves an overall transimpedance gain of 20 k? with a measured bandwidth of 4 GHz. The total power consumption of the chip is less than 120 mW and the chip die size is 0.75 mm x 1.25 mm. Irradiation testing of the chip shows no performance degradation after a dose rate of ...

  8. A seven-crystal Johann-type hard x-ray spectrometer at the Stanford Synchrotron Radiation Lightsource

    PubMed Central

    Sokaras, D.; Weng, T.-C.; Nordlund, D.; Alonso-Mori, R.; Velikov, P.; Wenger, D.; Garachtchenko, A.; George, M.; Borzenets, V.; Johnson, B.; Rabedeau, T.; Bergmann, U.

    2013-01-01

    We present a multicrystal Johann-type hard x-ray spectrometer (?5–18 keV) recently developed, installed, and operated at the Stanford Synchrotron Radiation Lightsource. The instrument is set at the wiggler beamline 6-2 equipped with two liquid nitrogen cooled monochromators – Si(111) and Si(311) – as well as collimating and focusing optics. The spectrometer consists of seven spherically bent crystal analyzers placed on intersecting vertical Rowland circles of 1 m of diameter. The spectrometer is scanned vertically capturing an extended backscattering Bragg angular range (88°–74°) while maintaining all crystals on the Rowland circle trace. The instrument operates in atmospheric pressure by means of a helium bag and when all the seven crystals are used (100 mm of projected diameter each), has a solid angle of about 0.45% of 4? sr. The typical resolving power is in the order of \\documentclass[12pt]{minimal}\\begin{document}$\\frac{E}{\\Delta E} \\sim 10\\,000$\\end{document}E?E?10000. The spectrometer's high detection efficiency combined with the beamline 6-2 characteristics permits routine studies of x-ray emission, high energy resolution fluorescence detected x-ray absorption and resonant inelastic x-ray scattering of very diluted samples as well as implementation of demanding in situ environments. PMID:23742527

  9. 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.

  10. Is it possible to infer the equation of state of a mixture of hard discs from that of the one-component system?

    NASA Astrophysics Data System (ADS)

    Santos, Andres

    Based on exact asymptotic properties of the composition-independent virial coefficients of a binary mixture of hard discs in the limits ? ? ?2/?1 ? 0, ? ? 1 and ? ? ?, R. J. Wheatley (1998, Molec. Phys., 93, 965) has recently proposed an approximate interpolation equation for these coefficients. In this note, the equation of state equivalent to this interpolation is obtained, expressing the compressibility factor of the mixture in terms of that of the pure system. An extension to an arbitrary number of components is also given. The equation of state derived here is compared with another one recently proposed by following a different route (Santos, A., Yuste, S. B., and Lopez de Haro, M., 1999, Molec. Phys., 96, 1) and with Monte Carlo simulation results. It is shown that the latter equation is more accurate than the former one, at least for not too disparate mixtures (0.7 ? ? < 1).

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

    Microsoft Academic Search

    Michael Wright; Jacques Millaud; David Nygren

    1993-01-01

    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

  12. Radiation hardness after very high neutron irradiation of minimum ionizing particle detectors based on 4H-SiC p+n junctions

    Microsoft Academic Search

    F. Moscatelli; A. Scorzoni; A. Poggi; M. Bruzzi; S. Sciortino; S. Lagomarsino; G. Wagner; I. Mandic; R. Nipoti

    2006-01-01

    In this work we analyzed the radiation hardness of SiC p+ n diodes used as minimum ionizing particle (MIP) detectors after very high 1 MeV neutron fluences. The diode structure is based on ion implanted p+ emitter in an n-type epilayer with thickness equal to 55 ?m and donor doping ND=2× 1014cm-3. The diode breakdown voltages were above 1000 V.

  13. Design and production of extremely radiation-hard 26% InGaP\\/GaAs\\/Ge triple-junction solar cells

    Microsoft Academic Search

    Mark A. Stan; Paul R. Sharps; Navid S. Fatemi; Frank Spadafora; Dan Aiken; Hong Q. Hou

    2000-01-01

    The authors report the design and testing of extremely radiation-hard high-efficiency large-area InGaP\\/GaAs\\/Ge triple-junction solar cells. The solar cell junctions are designed for longer minority carrier diffusion lengths after particle irradiation. The power remaining factors after 5E14 and 1E15 electrons\\/cm2 1-MeV electron radiation are 92% and 87.5%, respectively. These results are highest reported to date and are extremely desirable for

  14. 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.

  15. Role of five-quark components in radiative and strong decays of the ?(1405) resonance

    NASA Astrophysics Data System (ADS)

    An, C. S.; Saghai, B.; Yuan, S. G.; He, Jun

    2010-04-01

    Within an extended chiral constituent quark model, the three- and five-quark structure of the S01 resonance ?(1405) is investigated. Helicity amplitudes for electromagnetic decays [?(1405)??(1116)?, ?(1194)?] and transition amplitudes for strong decays [?(1405)??(1194)?, K-p] are derived, as well as the relevant decay widths. The experimental value for the strong decay width, ??(1405)?(??)°=50±2 MeV, is well reproduced with about 50% of a five-quark admixture in the ?(1405). Important effects owing to the configuration mixing among ?12PA, ?82PM, and ?84PM are found. In addition, transitions between the three- and the five-quark components in the baryons turn out to be significant in both radiative and strong decays of the ?(1405) resonance.

  16. 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.

  17. 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.

  18. 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)

  19. 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.

  20. The hard metal diseases.

    PubMed

    Cugell, D W

    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. PMID:1511554

  1. Two free air convection and radiation thermal models for planar magnetic components

    Microsoft Academic Search

    Kien Lai-Dac; Yves Lembeye; Benoit Sarrazin

    2011-01-01

    Thermal is considered as a principal constraint in size reduction of passive components in power electronics. In fact, the maximum temperature rise of component must be kept under a limit that heat dissipation cannot destroy the device materials. Therefore thermal modelling has to be taken in design optimisation of the components. We propose, in this paper, two analytical thermal models

  2. RADIATION EFFECTS ON ELECTRONIC SYSTEMS. DESIGNING ELECTRONIC SYSTEMS FOR NUCLEAR-POWERED AIRCRAFT REQUIRES KNOWING RESPONSE OF SYSTEM COMPONENTS AND MATERIALS TO IRRADIATION

    Microsoft Academic Search

    J. H. Levine; W. F. Ekern

    1960-01-01

    Electronic components were assembled into system and tested in a ; radiation field in order to determine radiation effects. The relative resistance ; of organic and inorganic materials is given in terms of energy absorbed (ergs\\/gm) ; for gamma rays and fast neutrons\\/ cm². Radiation damage to electron tubes ; is caused largely by fracture of the metal-to-glass seal, particularly

  3. 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

  4. Hardness assurance testing and radiation hardening by design techniques for silicon-germanium heterojunction bipolar transistors and digital logic circuits

    Microsoft Academic Search

    Akil K. Sutton

    2009-01-01

    Hydrocarbon exploration, global navigation satellite systems, computed tomography, and aircraft avionics are just a few examples of applications that require system operation at an ambient temperature, pressure, or radiation level outside the range covered by military specifications. The electronics employed in these applications are known as \\

  5. Hardness assurance testing and radiation hardening by design techniques for silicon-germanium heterojunction bipolar transistors and digital logic circuits

    NASA Astrophysics Data System (ADS)

    Sutton, Akil K.

    Hydrocarbon exploration, global navigation satellite systems, computed tomography, and aircraft avionics are just a few examples of applications that require system operation at an ambient temperature, pressure, or radiation level outside the range covered by military specifications. The electronics employed in these applications are known as "extreme environment electronics." On account of the increased cost resulting from both process modifications and the use of exotic substrate materials, only a handful of semiconductor foundries have specialized in the production of extreme environment electronics. Protection of these electronic systems in an extreme environment may be attained by encapsulating sensitive circuits in a controlled environment, which provides isolation from the hostile ambient, often at a significant cost and performance penalty. In a significant departure from this traditional approach, system designers have begun to use commercial off-the-shelf technology platforms with built in mitigation techniques for extreme environment applications. Such an approach simultaneously leverages the state of the art in technology performance with significant savings in project cost. Silicon-germanium is one such commercial technology platform that demonstrates potential for deployment into extreme environment applications as a result of its excellent performance at cryogenic temperatures, remarkable tolerance to radiation-induced degradation, and monolithic integration with silicon-based manufacturing. In this dissertation the radiation response of silicon-germanium technology is investigated, and novel transistor-level layout-based techniques are implemented to improve the radiation tolerance of HBT digital logic.

  6. Acoustic radiation from a pulsating spherical cap set on a spherical baffle near a hard\\/soft flat surface

    Microsoft Academic Search

    Seyyed M. Hasheminejad; Mahdi Azarpeyvand

    2004-01-01

    Radiation of sound from a spherical piston, set in the side of a rigid sphere, undergoing harmonic radial surface vibrations in an acoustic halfspace is analyzed in an exact fashion using the classical method of separation of variables. The method of images in combination with the translational addition theorems for spherical wave functions is employed to take the presence of

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

    E-print Network

    Nagpal, Charu

    2008-10-10

    the experimental studies on SEU in space electronics for SRAMs [15, 22], DRAMs [29], SRAM based Virtex FPGAs [7, 10, 11], ash memory based FPGAs [12], etc. Even though it is true that the amount of radiation received on the surface of the earth is lower than...

  8. Radiation-hard erbium optical fiber and fiber amplifier for both low- and high-dose space missions.

    PubMed

    Girard, S; Laurent, A; Pinsard, E; Robin, T; Cadier, B; Boutillier, M; Marcandella, C; Boukenter, A; Ouerdane, Y

    2014-05-01

    We present a new structure for erbium-doped optical fibers [hole-assisted carbon-coated, (HACC)] that, combined with an appropriate choice of codopants in the core, strongly enhances their radiation tolerance. We built an erbium-doped fiber amplifier based on this HACC fiber and characterize its degradation under ?-ray doses up to 315 krad (SiO2) in the ON mode. The 31 dB amplifier is practically radiation insensitive, with a gain change of merely -2.2×10(-3) dB/krad. These performances authorize the use of HACC doped fibers and amplifiers for various applications in environments associated with today's missions (of doses up to 50 krad) and even for future space missions associated with higher dose constraints. PMID:24784040

  9. Total ionizing dose radiation hardness of the ATLAS MDT-ASD and the HP-Agilent 0.5 um CMOS process

    E-print Network

    Posch, C

    2002-01-01

    A total ionizing dose (TID) test of the MDT-ASD, the ATLAS MDT front-end chip has been performed at the Harvard Cyclotron Lab. The MDT-ASD is an 8-channel drift tube read-out ASIC fabricated in a commercial 0.5 um CMOS process (AMOS14TB). The accumulated TID at the end of the test was 300 krad, delivered by 160 MeV protons at a rate of approximately 70 rad/sec. All 10 irradiated chips retained their full functionality and performance and showed only irrelevantly small changes in device parameters. As the total accumulated dose is substantially higher than the relevant ATLAS Radiation Tolerance Criteria (RTCtid), the results of this test indicate that MDT-ASD meets the ATLAS TID radiation hardness requirements. In addition, the results of this test correspond well with results of a 30 keV gamma TID irradiation test performed by us on an earlier prototype at the CERN x-ray facility as well as with results of other irradiation test on this process found in literature.

  10. Radiation-Hard ASICs for Optical Data Transmission K. K. Gan, P. Buchholz, H. P. Kagan, R. D. Kass, J. R. Moore, D. S. Smith, A. Wiese, M. Ziolkowski

    E-print Network

    Gan, K. K.

    Radiation-Hard ASICs for Optical Data Transmission K. K. Gan, P. Buchholz, H. P. Kagan, R. D. Kass, J. R. Moore, D. S. Smith, A. Wiese, M. Ziolkowski Abstract­ We have designed two ASICs for possible. 056Si74. K. K. Gan, H. P. Kagan, R. D. Kass, J. R. Moore, D. S. Smith are with the Department

  11. The use of passive personal neutron dosemeters to determine the neutron component of cosmic radiation fields in spacecraft

    NASA Astrophysics Data System (ADS)

    Bartlett, D. T.; Hager, L. G.; Tanner, R. T.

    For the altitude range and inclination of the International Space Station (ISS), secondary neutrons can be a major contributor to dose equivalent inside a spacecraft. The exact proportion is very dependent on the amount of shielding of the primary galactic cosmic radiation and trapped particles, but is likely to lie in the range of 10% to 50%. Personal neutron dosemeters of simple design, and processed using simple techniques developed for personal dosimetry may be used to estimate this neutron component. For the etch regime employed, the combination of high LET threshold (there is little response below a restricted LET200 in PADC of about 40 keV ?m-1), and poor angle dependence of response to high-energy charged particles (HZE), results in a much reduced overall response of the neutron dosimeter to the HZE component of the field in spacecraft and no response to protons of energy greater than about 2 MeV. Preliminary measurements indicate that for examples of the HZE component of the radiation fields in spacecraft, a correction of 5 to 10 % is necessary to account for the detector HZE response. Alternatively, an additional chemical etch can be carried out which allows discrimination. Recent results for exposures in low Earth orbit are reported.

  12. A novel epitaxially grown LSO-based thin-film scintillator for micro-imaging using hard synchrotron radiation.

    PubMed

    Douissard, Paul Antoine; Cecilia, Angelica; Martin, Thierry; Chevalier, Valentin; Couchaud, Maurice; Baumbach, Tilo; Dupré, Klaus; Kühbacher, Markus; Rack, Alexander

    2010-09-01

    The efficiency of high-resolution pixel detectors for hard X-rays is nowadays one of the major criteria which drives the feasibility of imaging experiments and in general the performance of an experimental station for synchrotron-based microtomography and radiography. Here the luminescent screen used for the indirect detection is focused on in order to increase the detective quantum efficiency: a novel scintillator based on doped Lu(2)SiO(5) (LSO), epitaxially grown as thin film via the liquid phase epitaxy technique. It is shown that, by using adapted growth and doping parameters as well as a dedicated substrate, the scintillation behaviour of a LSO-based thin crystal together with the high stopping power of the material allows for high-performance indirect X-ray detection. In detail, the conversion efficiency, the radioluminescence spectra, the optical absorption spectra under UV/visible-light and the afterglow are investigated. A set-up to study the effect of the thin-film scintillator's temperature on its conversion efficiency is described as well. It delivers knowledge which is important when working with higher photon flux densities and the corresponding high heat load on the material. Additionally, X-ray imaging systems based on different diffraction-limited visible-light optics and CCD cameras using among others LSO-based thin film are compared. Finally, the performance of the LSO thin film is illustrated by imaging a honey bee leg, demonstrating the value of efficient high-resolution computed tomography for life sciences. PMID:20724778

  13. Principal component-based radiative transfer model for hyperspectral sensors: theoretical concept

    Microsoft Academic Search

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

    2006-01-01

    Modern infrared satellite sensors such as the Atmospheric Infrared Sounder (AIRS), the Cross-Track Infrared Sounder (CrIS), the Tropospheric Emission Spectrometer (TES), the Geosynchronous Imaging Fourier Transform Spectrometer (GIFTS), and the 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, superfast radiative

  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. Quantifying components of aerosol-cloud-radiation interactions in climate models

    NASA Astrophysics Data System (ADS)

    Zelinka, Mark D.; Andrews, Timothy; Forster, Piers M.; Taylor, Karl E.

    2014-06-01

    The interaction of anthropogenic aerosols with radiation and clouds is the largest source of uncertainty in the radiative forcing of the climate during the industrial period. Here we apply novel techniques to diagnose the contributors to the shortwave (SW) effective radiative forcing (ERF) from aerosol-radiation-interaction (ERFari) and from aerosol cloud interaction (ERFaci) in experiments performed in phase 5 of the Coupled Model Intercomparison Project. We find that the ensemble mean SW ERFari+aci of -1.40±0.56 W m-2 comes roughly 25% from ERFari (-0.35±0.20 W m-2) and 75% from ERFaci (-1.04±0.67 W m-2). ERFari is made up of -0.62±0.30 W m-2 due to aerosol scattering opposed by +0.26 ± 0.12 W m-2 due to aerosol absorption and is largest near emission sources. The ERFari from nonsulfate aerosols is +0.13 ± 0.09 W m-2, consisting of -0.15±0.11 W m-2 of scattering and +0.29 ± 0.15 W m-2 of absorption. The change in clear-sky flux is a negatively biased measure of ERFari, as the presence of clouds reduces the magnitude and intermodel spread of ERFari by 40-50%. ERFaci, which is large both near and downwind of emission sources, is composed of -0.99±0.54 W m-2 from enhanced cloud scattering, with much smaller contributions from increased cloud amount and absorption. In models that allow aerosols to affect ice clouds, large increases in the optical depth of high clouds cause substantial longwave and shortwave radiative anomalies. Intermodel spread in ERFaci is dominated by differences in how aerosols increase cloud scattering, but even if all models agreed on this effect, over a fifth of the spread in ERFaci would remain due solely to differences in total cloud amount.

  16. Nuclear hardness assurance for aeronautical systems

    NASA Astrophysics Data System (ADS)

    Patrick, R. P.; Ferry, J. M.

    1980-10-01

    Nuclear hardness assurance for aircraft and airborne systems is considered from the point of view of an affordable research program's formulation and management prior to systems acquisitions. Among the threats to aircraft primary and secondary structures, flight crews, and electronics are: (1) blast overpressures of 1-3 psi for a 1 megaton blast, (2) blast-generated gusts of 75-100 ft/sec, (3) thermal emissions of 20-80 cal/sq cm, and (4) radiation effects such as neutron influence, gamma rate, total gamma dose, and electromagnetic pulse (EMP). The Hardness Assurance Documentation Program is introduced as a method by which hardened baseline systems meeting program requirements can be updated throughout the design and development process. Emphasis is placed on the unique vulnerability of electronic components to nuclear blast effects, above all the EMP generated by high-altitude detonations.

  17. Characterisation of a radiation hard front-end chip for the vertex detector of the LHCb experiment at CERN

    NASA Astrophysics Data System (ADS)

    van Bakel, N.; Baumeister, D.; van Beuzekom, M.; Bulten, H. J.; Feuerstack-Raible, M.; Jans, E.; Ketel, T.; Klous, S.; Löchner, S.; Sexauer, E.; Smale, N.; Snoek, H.; Trunk, U.; Verkooijen, H.

    2003-08-01

    The Beetle is a 128 channel analog pipelined readout chip which is intended for use in the silicon vertex locator (VELO) of the LHCb experiment at CERN. The Beetle chip is specially designed to withstand high radiation doses. Two Beetle1.1 chips bonded to a silicon strip detector have been tested with minimum ionizing particles. The main goal was to measure the signal-to-noise (S/N) ratio of the Beetle1.1 connected to a prototype VELO detector. Furthermore we investigated the general behaviour of the Beetle1.1. In this note we present the chip architecture, the measured (S/N) numbers as well as some characteristics (e.g. risetime, spillover) of the Beetle1.1 chip. Results from a total ionizing dose irradiation test are reported.

  18. Feasibility of modifying the high resolution infrared radiation sounder (HIRS/2) for measuring spectral components of Earth radiation budget

    NASA Technical Reports Server (NTRS)

    Koenig, E. W.; Holman, K. A.

    1980-01-01

    The concept of adding four spectral channels to the 20 channel HIRS/2 instrument for the purpose of determining the origin and profile of radiant existence from the Earth's atmosphere is considered. Methods of addition of three channels at 0.5, 1.0 and 1.6 micron m to the present 0.7 micron m visible channel and an 18-25 micron m channel to the present 19 channels spaced from 3.7 micron m to 15 micron m are addressed. Optical components and physical positions were found that permit inclusion of these added channels with negligible effect on the performance of the present 20 channels. Data format changes permit inclusion of the ERB data in the 288 bits allocated to HIRS for each scan element. A lamp and collimating optic assembly may replace one of the on board radiometric black bodies to provide a reference source for the albedo channels. Some increase in instrument dimensions, weight and power will be required to accommodate the modifications.

  19. 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

  20. 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 ...

  1. Developments for radiation hard silicon detectors by defect engineering—results by the CERN RD48 (ROSE) Collaboration

    NASA Astrophysics Data System (ADS)

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

    2001-06-01

    This report summarises the final results obtained by the RD48 collaboration. The emphasis is on the more practical aspects directly relevant for LHC applications. The report is based on the comprehensive survey given in the 1999 status report (RD48 3rd Status Report, CERN/LHCC 2000-009, December 1999), a recent conference report (Lindström et al. (RD48), and some latest experimental results. Additional data have been reported in the last ROSE workshop (5th ROSE workshop, CERN, CERN/LEB 2000-005). A compilation of all RD48 internal reports and a full publication list can be found on the RD48 homepage (http://cern.ch/RD48/). The success of the oxygen enrichment of FZ-silicon as a highly powerful defect engineering technique and its optimisation with various commercial manufacturers are reported. The focus is on the changes of the effective doping concentration (depletion voltage). The RD48 model for the dependence of radiation effects on fluence, temperature and operational time is verified; projections to operational scenarios for main LHC experiments demonstrate vital benefits. Progress in the microscopic understanding of damage effects as well as the application of defect kinetics models and device modelling for the prediction of the macroscopic behaviour has also been achieved but will not be covered in detail.

  2. Evidence for a Photospheric Component in the Prompt Emission of the Short GRB120323A and its Effects on the GRB Hardness-Luminosity Relation

    E-print Network

    Guiriec, S; Hascoët, R; Vianello, G; Mochkovitch, R; Ryde, F; Kouveliotou, C; Xiong, S; Bhat, P N; Foley, S; Grüber, D; Burgess, J M; McGlynn, S; McEnery, J; Gehrels, N

    2012-01-01

    The short GRB 120323A had the highest flux ever detected with the Fermi/GBM. Here we study its remarkable spectral properties and their evolution using two spectral models: (i) a single emission component scenario, where the spectrum is modeled by the empirical Band function, and (ii) a two component scenario, where thermal (Planck-like) 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 Epeak of the event is unusually soft for a short GRB, while adding a thermal component leads to more typical short GRB values. 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: (i) the values and evolution of the Band function parameters of the two component scenario, ...

  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. Successful Treatment of High Risk and Recurrent Pediatric Desmoids Using Radiation as a Component of Multimodality Therapy

    SciTech Connect

    Jabbari, Siavash [Department of Radiation Oncology, University of California, San Francisco, CA (United States); Andolino, David [Department of Radiation Oncology, Indiana University, Indianapolis, IN (United States); Weinberg, Vivian [Department of Biostatistics, University of California, San Francisco, CA (United States); Missett, Brian T. [Kaiser Permanente Medical Group, Santa Clara, CA (United States); Law, Jason [Department of Pediatrics, University of California, San Francisco, CA (United States); Wara, William M. [Department of Radiation Oncology, University of California, San Francisco, CA (United States); O'Donnell, Richard J. [Department of Orthopedic Surgery, University of California, San Francisco, CA (United States); Matthay, Katherine K.; DuBois, Steven G.; Goldsby, Robert [Department of Pediatrics, University of California, San Francisco, CA (United States); Haas-Kogan, Daphne A. [Department of Radiation Oncology, University of California, San Francisco, CA (United States)], E-mail: dhaaskogan@radonc.ucsf.edu

    2009-09-01

    Purpose: To evaluate the role of radiation therapy (RT) as a component of multimodality therapy for pediatric desmoids. Methods and Materials: Twenty-one children diagnosed between 1987 and 2005 were identified. Median age at start of treatment was 13 years (range, 2-21). Primary therapy consisted of resection alone (10), resection + external beam radiation therapy (EBRT) (5), resection + chemotherapy (CT; 3), EBRT alone (1), and CT alone (2). Results: The median follow-up from start of treatment is 75.7 months (range, 16-162). Examining patients with gross total resections (GTRs) (-) margins and those who had GTRs (+) margins followed by EBRT, only 2 of 7 failed primary treatment. Conversely, 13 of 14 patients with other primary treatments failed locally. Of the 15 patients who recurred, only 1 patient had a GTR (-) margins. Seven of these patients had salvage therapy that did not include RT, and of these only 2 have no evidence of disease (NED) at last follow-up. In contrast, the remaining 8 patients received RT as a component of their final salvage therapy and 7 of these are NED at last follow-up. At last follow-up, no patient has died, although toxicities of therapy have occurred. Conclusions: Local control is difficult to achieve in pediatric patients with desmoids. In the setting in which negative surgical margins cannot be achieved, RT plays a key role in achieving NED status. Even after multiple recurrences, successful salvage is achievable, particularly when high-dose focal therapy is incorporated.

  5. Muon Decay with Parity Nonconserving Interactions and Radiative Corrections in the Two-Component Theory

    Microsoft Academic Search

    Toichiro Kinoshita; Alberto Sirlin

    1957-01-01

    The decay of a polarized muon is studied in the case of the general four-component neutrino theory with the most general parity-nonconserving interaction. A three-parameter formula for the decay-electron distribution is obtained as a generalization of the Michel formula for an unpolarized muon. This general formula is examined to determine to what extent the observed spectrum enables one to decide

  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. 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.

  8. Decomposing aerosol cloud radiative effects into cloud cover, liquid water path and Twomey components in marine stratocumulus

    NASA Astrophysics Data System (ADS)

    Goren, Tom; Rosenfeld, Daniel

    2014-03-01

    A method for separating the three components of the marine stratocumulus (MSC) aerosol cloud interactions radiative effects, i.e., the cloud cover, liquid water path (LWP) and cloud drop radius (Twomey), was developed and tested. It is based on the assumption that changes in MSC cloud regimes that occur at short distance in homogeneous meteorological conditions are related to respective changes in the concentration of cloud condensation nuclei (CCN). The method was applied to 50 cases of well defined transitions from closed to open cells. It was found that the negative cloud radiative effect (CRE) over the closed cells is on average higher by 109 ± 18 Wm- 2 than that over the adjacent open cells. This large negative CRE is composed of the cloud cover (42 ± 8%), LWP (32 ± 8%) and Twomey (26 ± 6%) effects. This shows that the Twomey effect, which is caused by change in droplet concentration for a given LWP, contributes only a quarter of the difference in CRE, whereas the rest is contributed by added cloud water to the open cells both in the horizontal (cloud cover effect) and in the vertical (LWP effect) dimensions. The results suggest the possibility that anthropogenic aerosols that affect MSC-regime-changes might incur large negative radiative forcing on the global scale, mainly due to the cloud cover effect.

  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. 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.

  11. A novel hohlraum with ultrathin depleted-uranium-nitride coating layer for low hard x-ray emission and high radiation temperature

    E-print Network

    Guo, Liang; Xing, Peifeng; Li, Sanwei; Yi, Taimin; Kuang, Longyu; Li, Zhichao; Li, Renguo; Wu, Zheqing; Jing, Longfei; Zhang, Wenhai; Zhan, Xiayu; Yang, Dong; Jiang, Bobi; Yang, Jiamin; Liu, Shenye; Jiang, Shaoen; Li, Yongsheng; Liu, Jie; Huo, Wenyi; Lan, Ke

    2014-01-01

    An ultra-thin layer of uranium nitrides (UN) has been coated on the inner surface of the depleted uranium hohlraum (DUH), which has been proved by our experiment can prevent the oxidization of Uranium (U) effectively. Comparative experiments between the novel depleted uranium hohlraum and pure golden (Au) hohlraum are implemented on Shenguang III prototype laser facility. Under the laser intensity of 6*10^14 W/cm2, we observe that, the hard x-ray (> 1.8 keV) fraction of this uranium hohlraum decreases by 61% and the peak intensity of total x-ray flux (0.1 keV ~ 5 keV) increases by 5%. Two dimensional radiation hydrodynamic code LARED are exploited to interpret the above observations. Our result for the first time indicates the advantage of the UN-coated DUH in generating the uniform x-ray field with a quasi Planckian spectrum and thus has important implications in optimizing the ignition hohlraum design.

  12. Parallel detection and elimination of strongly connected components for radiation transport sweeps 

    E-print Network

    McLendon, William Clarence

    2001-01-01

    approach for finding strongly connected components in a di- rected graph without using depth-first search. The main idea of DCSC is to recursively partition the directed dependence graph (DDG), G = (V, E), so that all SCCs will be entirely contained... at random from G. Starting from v, mark() traverses G in breadth-first order in both forward and backward directions. It finishes when all the predecessors and successors of v have been visited and colored. A vertex is colored as predecessor or successor...

  13. 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.

  14. Hardness variability in commercial and hardened technologies

    Microsoft Academic Search

    M. R. Shaneyfelt; P. S. Winokur; T. L. Meisenheimer; F. W. Sexton; S. B. Roeske; M. G. Knoll

    1994-01-01

    Over the past 10 years, there have been a number of advances in methods to assess and assure the radiation hardness of microelectronics in military and space applications. At the forefront of these is the Qualified Manufacturers List (QML) methodology, in which the hardness of product is 'built-in' through statistical process control (SPC) of technology parameters relevant to the radiation

  15. Modification of solar radiation components under different atmospheric conditions in the Greater Athens Area, Greece

    NASA Astrophysics Data System (ADS)

    Kaskaoutis, D. G.; Kambezidis, H. D.; Jacovides, C. P.; Steven, M. D.

    2006-06-01

    The influence of the atmospheric turbidity on the spectral distribution of solar irradiance components is investigated using ground-based spectroradiometric measurements taken in Athens area during May 1995. It is found that both the diffuse-to-global and diffuse-to-direct-beam irradiance ratios exhibits a strong wavelength dependence and exponential curves associated with 99% of the variance can fit each parameter. These exponential curves are further modified as function of the solar zenith angle and atmospheric turbidity conditions. It is found that the slope of the curves strongly depends on the processes attenuating irradiance and aerosol optical characteristics in the short wavelengths. New relations are proposed, which allow the spectral distribution of diffuse irradiance to be estimated as a function of the measured broadband global and diffuse solar irradiances. The diffuse-to-direct-beam ratio, which is an indicator of the atmospheric transmittance, exhibits a strong wavelength and aerosol-loading dependence. The observed differences between turbid urban and clean rural atmospheres constitute a manifestation of contrasting air properties and influence solar irradiance spectra.

  16. Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence. http://pos.sissa.it RADIATION-HARD ASICS FOR OPTICAL DATA

    E-print Network

    Gan, K. K.

    -NonCommercial-ShareAlike Licence. http://pos.sissa.it RADIATION-HARD ASICS FOR OPTICAL DATA TRANSMISSION K.K. Gan1 , H.P. Kagan, R.D. Kass, J.R. Moore, D.S. Smith Department of Physics The Ohio State University Columbus, OH 43210, USA E-mail: gan@physics.osu.edu P. Buchholz, A. Wiese, M. Ziolkowski Fachbereich Physik Universität Siegen, Siegen

  17. Results of measurements on shuttle missions to the ISS of the neutron component of the radiation field

    NASA Astrophysics Data System (ADS)

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

    Secondary neutrons can be a major contributor to dose equivalent and effective dose inside a spacecraft for the altitude range and inclination of the International Space Station. The exact proportion is very dependent on the amount of shielding of the primary galactic cosmic radiation and trapped particles, but is likely to lie in the range of 10 60%. Neutron personal dosemeters of simple design, processed using simple techniques developed for routine personal dosimetry, have been used to determine the neutron component, including the neutron-like interactions of high energy protons. For the etch regime employed, the combination of high LET threshold (there is little response below a restricted LET200 in PADC of 30 40 keV/?m) and poor angle dependence of response to high-energy charged particles results in a much reduced overall response of the neutron dosemeter to the HZE component of the field in spacecraft and no response to protons of energy greater than about 1 MeV. A correction of 10 20% is necessary to account for the detector HZE response. Alternatively, an additional chemical etch can be carried out which allows discrimination.

  18. 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.

  19. Must "Hard Problems" Be Hard?

    ERIC Educational Resources Information Center

    Kolata, Gina

    1985-01-01

    To determine how hard it is for computers to solve problems, researchers have classified groups of problems (polynomial hierarchy) according to how much time they seem to require for their solutions. A difficult and complex proof is offered which shows that a combinatorial approach (using Boolean circuits) may resolve the problem. (JN)

  20. Calculating Radiation Exposures during Use of 14C-Labeled Nutrients, Food Components, and Biopharmaceuticals To Quantify Metabolic Behavior in Humans

    PubMed Central

    2010-01-01

    14C has long been used as a tracer for quantifying the in vivo human metabolism of food components, biopharmaceuticals, and nutrients. Minute amounts (?1 × 10 ?18 mol) of 14C can be measured with high-throughput 14C-accelerator mass spectrometry (HT 14C-AMS) in isolated chemical extracts of biological, biomedical, and environmental samples. Availability of in vivo human data sets using a 14C 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 14C 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 14C-?-carotene, 14C-?-tocopherol, 14C-lutein, and 14C-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 ?Sv to whole body and from 0.2 to 3.4 ?Sv 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 ?Sv. PMID:20349979

  1. Electromagnetic Analysis of Synchronous and Asynchronous Circuits using Hard

    E-print Network

    Moore, Simon

    Electromagnetic Analysis of Synchronous and Asynchronous Circuits using Hard Disc Heads Theo the magnetic field component ­ Inductive hard disc head (circa 1990) ­ Giant magnetoresistive hard disc head to `scope · Couldn't detect ALU activity, only bus traffic and clock on bond wires #12;Inductive hard disc

  2. Role of Principal Component Analysis in Predicting Toxicity in Prostate Cancer Patients Treated With Hypofractionated Intensity-Modulated Radiation Therapy

    SciTech Connect

    Vesprini, Danny [Department of Radiation Oncology, Sunnybrook Odette Cancer Center, Toronto, Ontario (Canada); Radiation Medicine Program, Princess Margaret Hospital, University Health Network, and Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Sia, Michael [Radiation Medicine Program, Princess Margaret Hospital, University Health Network, and Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Lockwood, Gina [Department of Clinical Study Co-ordination and Biostatistics, Princess Margaret Hospital, University Health Network, Toronto, Ontario (Canada); Moseley, Douglas; Rosewall, Tara; Bayley, Andrew; Bristow, Robert; Chung, Peter; Menard, Cynthia; Milosevic, Michael; Warde, Padraig [Radiation Medicine Program, Princess Margaret Hospital, University Health Network, and Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Catton, Charles, E-mail: charles.catton@rmp.uhn.on.ca [Radiation Medicine Program, Princess Margaret Hospital, University Health Network, and Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada)

    2011-11-15

    Purpose: To determine if principal component analysis (PCA) and standard parameters of rectal and bladder wall dose-volume histograms (DVHs) of prostate cancer patients treated with hypofractionated image-guided intensity-modulated radiotherapy (hypo-IMRT) can predict acute and late gastrointestinal (GI) toxicity. Methods and Materials: One hundred twenty-one patients underwent hypo-IMRT at 3 Gy/fraction, 5 days/week to either 60 Gy or 66 Gy, with daily online image guidance. Acute and late GI and genitourinary (GU) toxicity were recorded weekly during treatment and at each follow-up. All Radiation Therapy Oncology Group (RTOG) criteria toxicity scores were dichotomized as <2 and {>=}2. Standard dosimetric parameters and the first five to six principal components (PCs) of bladder and rectal wall DVHs were tested for association with the dichotomized toxicity outcomes, using logistic regression. Results: Median follow-up of all patients was 47 months (60 Gy cohort= 52 months; 66 Gy cohort= 31 months). The incidence rates of {>=}2 acute GI and GU toxicity were 14% and 29%, respectively, with no Grade {>=}3 acute GU toxicity. Late GI and GU toxicity scores {>=}2 were 16% and 15%, respectively. There was a significant difference in late GI toxicity {>=}2 when comparing the 66 Gy to the 60 Gy cohort (38% vs. 8%, respectively, p = 0.0003). The first PC of the rectal DVH was associated with late GI toxicity (odds ratio [OR], 6.91; p < 0.001), though it was not significantly stronger than standard DVH parameters such as Dmax (OR, 6.9; p < 0.001) or percentage of the organ receiving a 50% dose (V50) (OR, 5.95; p = 0 .001). Conclusions: Hypofractionated treatment with 60 Gy in 3 Gy fractions is well tolerated. There is a steep dose response curve between 60 Gy and 66 Gy for RTOG Grade {>=}2 GI effects with the dose constraints employed. Although PCA can predict late GI toxicity for patients treated with hypo-IMRT for prostate cancer, it provides no additional information over using more standard DVH parameters.

  3. 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

  4. Study of radiation response on single-junction component sub-cells in triple-junction solar cells

    Microsoft Academic Search

    M. Imaizumi; T. Takamoto; T. Sumita; T. Ohshima; M. Yamaguchi; S. Matsuda; A. Ohi; T. Kamiya

    2003-01-01

    The radiation responses of InGaP, (In)GaAs and Ge single-junction sub-cells in a triple-junction space solar cell are studied in order to develop a device simulator which predicts the EOL performance of space solar cells. InGaP top-cells exhibit no significant difference in radiation degradation trends between AM0 light and dark conditions during irradiation. The radiation tolerance of (In)GaAs middle-cells degrades with

  5. Neutron-produced component of radiation background on orbit, surface and subsurface of Mars: data from HEND/Odyssey

    NASA Astrophysics Data System (ADS)

    Mitrofanov, I.; Kozyrev, A.; Litvak, M.; Sanin, A.; Tret'yakov, V.

    The fluxes of neutrons and gamma-rays from Mars are produced by the bombardment of the surface layer by galactic cosmic rays. Subsurface layer of 1-2 meters emits the leakage flux of neutrons, which energy spectrum depends on the composition of subsurface material, mainly on the content of hydrogen in the soil. Gamma rays are produced by nuclei of the main soil elements, which are exited either by inelastic collisions or by capture reactions with neutrons. Therefore, Mars has much enhanced radiation background in comparison with the Earth both on the surface and in the surrounding space up to several thousands kilometers away. Data of neutrons measurements from HEND/Odyssey will be presented both for interplanetary flight to Mars and on the orbit around mars. These data will be transformed into the neutron-produced component of radiation dose at these conditions. The map of neutron-produced doses will be presented for orbital altitude of 400 km above Mars. Model-dependent deconvolution of orbital data will be described, which allows to estimate the leakage flux of neutrons on the surface of Mars. It will be shown that content of ground water is the main factor, which determines the local radiation background on the surface. Using the values of leakage flux of neutrons at the surface, neutron-produced doses will be estimated for different regions of Mars with different content of ground water. Neutron-produced doses will be also estimated in the shallow subsurface of different regions of Mars down to 3 meters. The data for neutron-produced doses over the Mars will be useful for creation of comprehensive engineering model of radiation environment on the planet. rom A soil with larger content of hydrogen moderates much better original neutrons from the energy range about 10-20 MeV down to the thermal energy. On Mars hydrogen is associated with water. Therefore, regions with larger and smaller content of water in the soil emit lower and higher fluxes of epithermal neutrons, and, correspondingly, higher and lower flux of thermal neutrons. The measurements by High Energy Neutron Detector (HEND) on Mars Odyssey have revealed very large regional variation of epithermal neutrons by a factor of 10 on the surface of Mars with linear resolution about 200-300 km. Two huge polward depressions of neutron emission were found above latitudes of 50-60 and identified as Northern and Southern permafrost regions with very high content of water ice up to 50 wt%. They are much larger than the residual polar caps, and could contain the major fraction of subsurface water on the planet. Also, HEND found that two opposite equatorial regions Arabia and Memnonia contain about 10 wt% of water under the top layer of dry soil with a thickness about 30 g/cm2. If the content of water were so large for averaging over 200-300 km along a surface, one could guess that local spots with size of several km could contain the water-ice dominating subsurface. After orbital mapping, the next step of neutron measurements on Mars could be associated with balloon mission, which may cover the circle at high latitudes around a pole and measure content of water ice along a trace with a resolution of 3-5 km. These data may allow to detect the best water-ice rich spots, as targets for future landing missions for direct access to ground water. Finally, the most precise localization of 1-3 meter surface sites with high ground water could be provided by active measurements of Dynamic Albedo of Neutrons (DAN) produced by pulsing neutron generator. DAN could determine a layering structure of ground water, because die away curves of induced thermal and epithermal neutrons depend both on content and depth of water in the subsurface. DAN on the Mars rover is the best facility for searching for ground water ice sites either for their analysis in situ or for returns of water-bearing samples on the Earth.

  6. Roller burnishing of hard turned surfaces

    Microsoft Academic Search

    F. Klocke; J. Liermann

    1998-01-01

    In a hard roller burnishing operation, a hydrostatically borne ceramic ball rolls over the component surface under high pressures. The roughness peaks are flattened and the quality of the workpiece surface is improved. When combined with hard turning, this process provides a manufacturing alternative to grinding and honing operations.The studies determined optimum working parameter ranges. Parameter settings were shown to

  7. Growth enhancement of soybean (Glycine max) upon exclusion of UV-B and UV-B/A components of solar radiation: characterization of photosynthetic parameters in leaves.

    PubMed

    Guruprasad, Kadur; Kadur, Guruprasad; Bhattacharjee, Swapan; Swapan, Bhattacharjee; Kataria, Sunita; Sunita, Kataria; Yadav, Sanjeev; Sanjeev, Yadav; Tiwari, Arjun; Arjun, Tiwari; Baroniya, Sanjay; Sanjay, Baroniya; Rajiv, Abhinav; Abhinav, Rajiv; Mohanty, Prasanna

    2007-01-01

    Exclusion of UV (280-380 nm) radiation from the solar spectrum can be an important tool to assess the impact of ambient UV radiation on plant growth and performance of crop plants. The effect of exclusion of UV-B and UV-A from solar radiation on the growth and photosynthetic components in soybean (Glycine max) leaves were investigated. Exclusion of solar UV-B and UV-B/A radiation, enhanced the fresh weight, dry weight, leaf area as well as induced a dramatic increase in plant height, which reflected a net increase in biomass. Dry weight increase per unit leaf area was quite significant upon both UV-B and UV-B/A exclusion from the solar spectrum. However, no changes in chlorophyll a and b contents were observed by exclusion of solar UV radiation but the content of carotenoids was significantly (34-46%) lowered. Analysis of chlorophyll (Chl) fluorescence transient parameters of leaf segments suggested no change in the F v/F m value due to UV-B or UV-B/A exclusion. Only a small reduction in photo-oxidized signal I (P700+)/unit Chl was noted. Interestingly the total soluble protein content per unit leaf area increased by 18% in UV-B/A and 40% in UV-B excluded samples, suggesting a unique upregulation of biosynthesis and accumulation of biomass. Solar UV radiation thus seems to primarily affect the photomorphogenic regulatory system that leads to an enhanced growth of leaves and an enhanced rate of net photosynthesis in soybean, a crop plant of economic importance. The presence of ultra-violet components in sunlight seems to arrest carbon sequestration in plants. PMID:17665152

  8. CMOS Hardness Assurance through Process Controls and Optimized Design Procedures

    Microsoft Academic Search

    T. J. Sanders

    1977-01-01

    Total Dose Hardness Assurance for complimentary MOS integrated circuits is recognized throughout the industry as a difficult problem. Most of the hardness assurance proposals to date have included a large amount of radiation testing on a diffision lot or wafer basis to help guarantee the hardness of a small group of integrated circuits. This, in general, is very expensive, and

  9. Development of a plasma panel radiation detector

    E-print Network

    Ball, R; Ben-Moshe, M; Benhammou, Y; Bensimon, R; Chapman, J W; Etzion, E; Ferretti, C; Friedman, P S; Levin, D S; Silver, Y; Varner, R L; Weaverdyck, C; Wetzel, R; Zhou, B; Anderson, T; McKinny, K; Bentefour, E H

    2014-01-01

    This article reports on an investigation of a radiation detector based on plasma display panel technology. The plasma panel sensor (PPS) is a variant of micropattern gas radiation detectors. PPS components are non-reactive and intrinsically radiation-hard materials, such as glass substrates, metal electrodes and inert gas mixtures. Plasma display panels used as detectors were tested with cosmic ray muons, beta rays and gamma rays, protons, and thermal neutrons. The results demonstrated risetimes and time resolution of a few nanoseconds, as well as spatial resolution compatible with the pixel pitch.

  10. BOOKSHELF Hard Disk Drive

    E-print Network

    Benmei, Chen

    » BOOKSHELF Hard Disk Drive Servo Systems, 2nd edition by B.M. CHEN, T.H. LEE, K. PENG, and V- widths ever higher as higher frequency disturbances become relevant. THE BOOK Hard Disk Drive Servo I of Hard Disk Drive Servo Systems briefly discusses the history of hard drive control and the disk

  11. 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

  12. 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.

  13. 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

  14. Radiators

    Microsoft Academic Search

    1985-01-01

    A heat-exchange radiator is connected to a fluid flow circuit by a connector which provides one member of an interengageable spigot and socket pair for push-fit, fluid-tight, engagement between the connector and the radiator, with latching formations at least one of which is resilient. Preferably the connector carries the spigot which tapers and engages with a socket of corresponding shape,

  15. Radiation 

    E-print Network

    Unknown

    2011-08-17

    State. s. ABSTRACT This study is an attempt to find a tentative atmospheric index of human comfort and to show its applications for the area of College Station~ Texas. Temperature, relative humidity~ air move- ment, and global short-wave radiation... (direct plus diffuse) were combined into a single numerical expression for outdoor human comfort. The contribution of global short-wave radiation to the heat load on man also is evaluated in a single numerical expression, and expressed as an equivalent...

  16. 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

  17. CONTROL OF LASER RADIATION PARAMETERS: Competition between spectral components of a tunable laser accompanying biharmonic excitation of an acoustooptic deflector

    NASA Astrophysics Data System (ADS)

    Kravchenko, V. I.; Lyushchenko, A. I.; Parkhomenko, Yu N.

    1992-01-01

    An investigation was made of the laws governing the formation of a multifrequency emission spectrum of a laser electronically tuned by an acoustooptic deflector. A model was proposed (and verified) to take into account both the competition between the spectral components in the active medium and the redistribution of their energies (by two sound waves) caused by the absence of selection in the deflector. A mechanism was suggested to account for the substantial difference between the energy efficiencies of the main optical components of the laser and for an auxiliary component which appeared. This mechanism defined a distinctive three-frequency lasing regime. A study was made of the influence of the sound wave parameters on the spectral characteristics, which made it possible to establish several laser control algorithms.

  18. 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.

  19. Investigation of the continual component of high-current vacuum arc radiation in the optical spectral range

    Microsoft Academic Search

    A. A. Logatchev; A. M. Chaly; M. V. Lisnyak; K. K. Zabello; S. M. Shkol'nik

    2010-01-01

    Measurements of continual radiation of a high-current vacuum arc of the length of 8 mm with copper electrodes of 30 mm in diameter at the currents 5.5 kA and 12 kA were carried out. The induction of the external magnetic field that stabilized the arc was ? 0.45 T. Data about relative changes in the distribution of electron concentration in

  20. 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.

  1. 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.

  2. Hardness testing. 2nd edition

    SciTech Connect

    Chandler, H. [ed.

    1999-07-01

    This basic book provides a comprehensive overview of hardness testing, including the various methods and equipment used, testing applications, and the selection of testing methods. The revised and updated second edition features expanded information on microhardness testing, specialized hardness tests; and hardness testing standards. Contents include: introduction to hardness testing; brinell testing; rockwell hardness testing; vickers hardness testing; microhardness testing; scleroscope and leeb hardness testing; hardness testing applications; and selection of hardness testing methods.

  3. Wear of hard materials by hard particles

    SciTech Connect

    Hawk, Jeffrey A.

    2003-10-01

    Hard materials, such as WC-Co, boron carbide, titanium diboride and composite carbide made up of Mo2C and WC, have been tested in abrasion and erosion conditions. These hard materials showed negligible wear in abrasion against SiC particles and erosion using Al2O3 particles. The WC-Co materials have the highest wear rate of these hard materials and a very different material removal mechanism. Wear mechanisms for these materials were different for each material with the overall wear rate controlled by binder composition and content and material grain size.

  4. Radiation

    Microsoft Academic Search

    Erik Seedhouse

    \\u000a It is more than forty years since astronauts ventured beyond Earth’s protective magnetic shield and travelled to the Moon.\\u000a Although the Apollo missions subjected astronauts to space radiation, the short duration minimized the risk, but an ECM will\\u000a subject astronauts to much longer exposure. In fact, astronauts will be in deep space for so long, they will run the risk

  5. Dissecting Soft Radiation with Factorization

    E-print Network

    Tackmann, Frank J.

    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 ...

  6. Hardness variability in commercial and hardened technologies

    SciTech Connect

    Shaneyfelt, M.R.; Winokur, P.S.; Meisenheimer, T.L.; Sexton, F.W.; Roeske, S.B.; Knoll, M.G.

    1994-03-01

    Over the past 10 years, there have been a number of advances in methods to assess and assure the radiation hardness of microelectronics in military and space applications. At the forefront of these is the Qualified Manufacturers List (QML) methodology, in which the hardness of product is ``built-in`` through statistical process control (SPC) of technology parameters relevant to the radiation response, test structure to integrated circuit (IC) correlations, and techniques for extrapolating laboratory test results to varying radiation scenarios. At the same time, there has been renewed interest in the use of commercial technology -- with its enhanced performance, reduced cost, and higher reliability -- in military and space systems. In this paper, we initially demonstrate the application of QML techniques to assure and control the radiation response of hardened technologies. Through several examples, we demonstrate intra-die, wafer-to-wafer, and lot-to-lot variations in a hardened technology. We observe 10 to 30% variations in key technology parameters that result from variability in geometry, process, and design layout. Radiation-induced degradation is seen to mirror preirradiation characteristics. We then evaluate commercial technologies and report considerably higher variability in radiation hardness, i.e., variations by a factor of two to five. This variability is shown to arise from a lack of control of technology parameters relevant to the radiation response, which a commercial manufacturer has no interest in controlling in a normal process flow.

  7. 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.

  8. 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

  9. Effect of UV radiation and temperature on the emission of methane from plant biomass and structural components

    NASA Astrophysics Data System (ADS)

    Vigano, I.; van Weelden, H.; Holzinger, R.; Keppler, F.; McLeod, A.; Röckmann, T.

    2008-06-01

    The recently reported finding that plant matter and living plants produce significant amounts of the important greenhouse gas methane under aerobic conditions has led to an intense scientific and public controversy. Whereas some studies question the up-scaling method that was used to estimate the global source strength, others have suggested that experimental artifacts could have caused the reported signals, and two studies, one based on isotope labeling, have recently reported the absence of CH4 emissions from plants. Here we show using several independent experimental analysis techniques that dry and detached fresh plant matter, as well as several structural plant components, emit significant amounts of methane upon irradiation with UV light and/or heating. Emissions from UV irradiation are almost instantaneous, indicating a direct photochemical process. Long-time irradiation experiments demonstrate that the size of the CH4 producing reservoir is large, exceeding potential interferences from degassing or desorption processes by several orders of magnitude. A dry leaf of a pure 13C plant produces 13CH4 at a similar rate as dry leaves of non-labeled plants produce non-labeled methane.

  10. 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.

  11. 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.

  12. 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.

  13. Integrating fiber optic radiation dosimeter

    SciTech Connect

    Soltani, P.K.; Wrigley, C.Y.; Storti, G.M.; Creager, R.E.

    1989-03-01

    The purpose of this research effort was to determine the feasibility of forming a radiation sensor coupled to an optical fiber capable of measuring gamma photon, x-ray, and beta particle dose rates and integrated dose, and to construct a prototype dosimeter read-out system utilizing the fiber optic sensor. The key component of the prototype dosimeter system is a newly developed radiation sensitive storage phosphor. When this phosphor is excited by energetic radiation, a proportionate population of electron-hole pairs are created which become trapped at specific impurities within the phosphor. Trapped electrons can subsequently be stimulated optically with near-infrared at approximately 1 micrometer wavelength; the electrons can recombine with holes at luminescent centers to produce a luminescence which is directly proportional to the trapped electron population, and thus to the radiation exposure. By attaching the phosphor to the end of an optical fiber, it is possible to transmit both the IR optical stimulation and the characteristic phosphor luminescence through the fiber to and from the read-out instrument, which can be located far (e.g., kilometers) from the radiation field. This document reports on the specific design of the prototype system and its operating characteristics, including its sensitivity to various radiation dose rates and energies, its dynamic range, signal-to-noise ratio at various radiation intensities, and other system characteristics. Additionally, the radiation hardness of the phosphor and fiber are evaluated. 17 refs., 29 figs., 5 tabs.

  14. 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.

  15. A thin diffuse component of the Galactic Ridge X-ray emission and heating of the interstellar medium contributed by the radiation of Galactic X-ray binaries

    E-print Network

    Molaro, Margherita; Sunyaev, Rashid

    2013-01-01

    We suggest a thin (scale height ~80 pc) diffuse component to the Galactic Ridge X-ray emission (GRXE) arising from the scattering of the radiation of bright X-ray binaries (XBs) by the interstellar medium. The morphology of the scattered component is expected to trace the clumpy molecular and HI clouds. We calculate this contribution to the GRXE from known Galactic XBs assuming that they are all persistent. The known XBs sample is however incomplete as it is flux-limited and spans the small lifetime of X-ray astronomy (~50 years), compared to the characteristic time of 1000-10000 years that would contribute to the diffuse emission observed today due to time delays. We therefore also use a simulated sample of sources, to estimate the diffuse emission we should expect in an optimistic case assuming that the X-ray luminosity of our Galaxy is on average similar to that of other galaxies. In the calculations we also take into account the enhancement of the total scattering cross section due to coherence effects in...

  16. Virial coefficients and equations of state for mixtures of hard discs, hard spheres and hard hyperspheres

    NASA Astrophysics Data System (ADS)

    Santos, A.; Yuste, S. B.; López de Haro, M.

    The composition-independent virial coefficients of a d-dimensional binary mixture of (additive) hard hyperspheres following from a recent proposal for the equation of state of the mixture (SANTOS, A., YUSTE, S. B., and LÓPEZ DE HARO, M., 1999, Molec. Phys., 96 , 1) are examined. Good agreement between theoretical estimates and available exact or numerical results is found for d = 2, 3, 4 and 5, except for mixtures whose components are very disparate in size. A slight modification that remedies this deficiency is introduced and the resummation of the associated virial series is carried out, leading to a new proposal for the equation of state. The case of binary hard sphere mixtures (d = 3) is analysed in some detail.

  17. DCE-MRI defined subvolumes of a brain metastatic lesion by principle component analysis and fuzzy-c-means clustering for response assessment of radiation therapy

    SciTech Connect

    Farjam, Reza; Tsien, Christina I.; Lawrence, Theodore S. [Department of Radiation Oncology, University of Michigan, 1500 East Medical Center Drive, SPC 5010, Ann Arbor, Michigan 48109-5010 (United States)] [Department of Radiation Oncology, University of Michigan, 1500 East Medical Center Drive, SPC 5010, Ann Arbor, Michigan 48109-5010 (United States); Cao, Yue, E-mail: yuecao@umich.edu [Department of Radiation Oncology, University of Michigan, 1500 East Medical Center Drive, SPC 5010, Ann Arbor, Michigan 48109-5010 (United States) [Department of Radiation Oncology, University of Michigan, 1500 East Medical Center Drive, SPC 5010, Ann Arbor, Michigan 48109-5010 (United States); Department of Radiology, University of Michigan, 1500 East Medical Center Drive, Med Inn Building C478, Ann Arbor, Michigan 48109-5842 (United States); Department of Biomedical Engineering, University of Michigan, 2200 Bonisteel Boulevard, Ann Arbor, Michigan 48109-2099 (United States)

    2014-01-15

    Purpose: To develop a pharmacokinetic modelfree framework to analyze the dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) data for assessment of response of brain metastases to radiation therapy. Methods: Twenty patients with 45 analyzable brain metastases had MRI scans prior to whole brain radiation therapy (WBRT) and at the end of the 2-week therapy. The volumetric DCE images covering the whole brain were acquired on a 3T scanner with approximately 5 s temporal resolution and a total scan time of about 3 min. DCE curves from all voxels of the 45 brain metastases were normalized and then temporally aligned. A DCE matrix that is constructed from the aligned DCE curves of all voxels of the 45 lesions obtained prior to WBRT is processed by principal component analysis to generate the principal components (PCs). Then, the projection coefficient maps prior to and at the end of WBRT are created for each lesion. Next, a pattern recognition technique, based upon fuzzy-c-means clustering, is used to delineate the tumor subvolumes relating to the value of the significant projection coefficients. The relationship between changes in different tumor subvolumes and treatment response was evaluated to differentiate responsive from stable and progressive tumors. Performance of the PC-defined tumor subvolume was also evaluated by receiver operating characteristic (ROC) analysis in prediction of nonresponsive lesions and compared with physiological-defined tumor subvolumes. Results: The projection coefficient maps of the first three PCs contain almost all response-related information in DCE curves of brain metastases. The first projection coefficient, related to the area under DCE curves, is the major component to determine response while the third one has a complimentary role. In ROC analysis, the area under curve of 0.88 ± 0.05 and 0.86 ± 0.06 were achieved for the PC-defined and physiological-defined tumor subvolume in response assessment. Conclusions: The PC-defined subvolume of a brain metastasis could predict tumor response to therapy similar to the physiological-defined one, while the former is determined more rapidly for clinical decision-making support.

  18. 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.

  19. Ormosils of high hardness

    SciTech Connect

    Iwamoto, Takashi; Mackenzie, J.D. [Univ. of California, Los Angeles, CA (United States). Dept. of Materials Science and Engineering

    1994-12-31

    Organically modified silicates (ormosils) of high hardness were prepared by the reactions of tetraethoxysilane (TEOS) and polydimethylsiloxane (PDMS) aided by ultrasonic irradiation. The mechanisms leading to the hard ormosil formation were investigated by liquid state {sup 29}Si NMR spectroscopy. PDMS chains were found to be broken into shorter chains and/or 4-membered siloxane rings during the reaction and finally, all PDMS chains were chemically incorporated as short chains into silica networks. Vickers hardnesses of the hard ormosils were measured and compared with those of the hardest transparent plastics. Whereas the hardest transparent plastics have Vickers hardness values of less than 25 kg/mm{sup 2}, the hard ormosils have Vickers hardnesses tip to higher than 150 kg/mm{sup 2}. A theoretical model was developed for the calculation of Vickers hardnesses of the hard ormosils and agreed well with experimental results. Predictions based on this theory indicate that even harder ormosils can be made when Al{sub 2}O{sub 3}, ZrO{sub 2} and TiO{sub 2} are substituted for SiO{sub 2}. Results based on these new ormosils are also presented.

  20. A thin diffuse component of the Galactic ridge X-ray emission and heating of the interstellar medium contributed by the radiation of Galactic X-ray binaries

    NASA Astrophysics Data System (ADS)

    Molaro, Margherita; Khatri, Rishi; Sunyaev, Rashid A.

    2014-04-01

    We predict a thin diffuse component of the Galactic ridge X-ray emission (GRXE) arising from the scattering of the radiation of bright X-ray binaries (XBs) by the interstellar medium. This scattered component has the same scale height as that of the gaseous disk (~80 pc) and is therefore thinner than the GRXE of stellar origin (scale height ~130 pc). The morphology of the scattered component is furthermore expected to trace the clumpy molecular and HI clouds. We calculate this contribution to the GRXE from known Galactic XBs assuming that they are all persistent. The known XBs sample is incomplete, however, because it is flux limited and spans the lifetime of X-ray astronomy (~50 years), which is very short compared with the characteristic time of 1000-10 000 years that would have contributed to the diffuse emission observed today due to time delays. We therefore also use a simulated sample of sources, to estimate the diffuse emission we should expect in an optimistic case assuming that the X-ray luminosity of our Galaxy is on average similar to that of other galaxies. In the calculations we also take into account the enhancement of the total scattering cross-section due to coherence effects in the elastic scattering from multi-electron atoms and molecules. This scattered emission can be distinguished from the contribution of low X-ray luminosity stars by the presence of narrow fluorescent K-? lines of Fe, Si, and other abundant elements present in the interstellar medium and by directly resolving the contribution of low X-ray luminosity stars. We find that within 1° latitude of the Galactic plane the scattered emission contributes on average 10 - 30% of the GRXE flux in the case of known sources and over 50% in the case of simulated sources. In the latter case, the scattered component is found to even dominate the stellar emission in certain parts of the Galactic plane. X-rays with energies ?1 keV from XBs should also penetrate deep inside the HI and molecular clouds, where they are absorbed and heat the interstellar medium. We find that this heating rate dominates the heating by cosmic rays (assuming a solar neighborhood energy density) in a considerable part of the Galaxy. Appendices are available in electronic form at http://www.aanda.org

  1. 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.

  2. Memory Hard Drive Peripherals

    E-print Network

    Stojmenovic, Ivan

    1! CSI3131 Topics CPU Memory Hard Drive Peripherals Computing Systems OS Overview StructureDeadlocks M em ory M anagem ent Basic Memory Managermtn Virtual Memory Storage and I/O File Systems Hard Drive Management Swap I/O Management 2 Module 7: Memory Management Reading: Chapter 8 § To provide a detailed

  3. DIELECTRIC SPECTROSCOPY OF HARD RED WINTER WHEAT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The dielectric properties (components of the complex permittivity relative to free space) of ground hard red winter wheat of 11 to 25 percent moisture content were determined by dielectric spectroscopy measurements with an open-ended coaxial-line probe and impedance analyzer over the frequency range...

  4. Radiation hardness of cryogenic silicon detectors

    Microsoft Academic Search

    T. O Niinikoski; M. Abreu; W. Bell; P. Berglund; W de Boer; E. Borchi; K. Borer; M. Bruzzi; S. Buontempo; L. Casagrande; S. Chapuy; V. Cindro; P. Collins; N D’Ambrosio; C Da Viá; S. R. H Devine; B. Dezillie; Z. Dimcovski; V. Eremin; A. Esposito; V. Granata; E. Grigoriev; S. Grohmann; F. Hauler; E. Heijne; S. Heising; S. Janos; L. Jungermann; I. Konorov; Z. Li; C. Lourenço; M. Mikuz; V O’Shea; S. Pagano; V. G Palmieri; S. Paul; S. Pirollo; K. Pretzl; P. Rato Mendes; G. Ruggiero; K. Smith; P. Sonderegger; P. Sousa; E. Verbitskaya; S. Watts; M. Zavrtanik

    2002-01-01

    We shall review test results which show that silicon detectors can withstand at 130K temperature a fluence of 2×1015cm–2 of 1MeV neutrons, which is about 10 times higher than the fluence tolerated by the best detectors operated close to room temperature. The tests were carried out on simple pad devices and on microstrip detectors of different types. The devices were

  5. Application of approximations for joint cumulative k-distributions for mixtures to FSK radiation heat transfer in multi-component high temperature non-LTE plasmas

    NASA Astrophysics Data System (ADS)

    Maurente, André; França, Francis H. R.; Miki, Kenji; Howell, John R.

    2012-08-01

    Approximations for joint cumulative k-distribution for mixtures are efficient for full spectrum k-distribution (FSK) computations. These approximations provide reduction of the database that is necessary to perform FSK computation when compared to the direct approach, which uses cumulative k-distributions computed from the spectrum of the mixture, and also less computational expensive when compared to techniques in which RTE's are required to be solved for each component of the mixture. The aim of the present paper is to extend the approximations for joint cumulative k-distributions for non-LTE media. For doing that, a FSK to non-LTE media formulation well-suited to be applied along with approximations for joint cumulative k-distributions is presented. The application of the proposed methodology is demonstrated by solving the radiation heat transfer in non-LTE high temperature plasmas composed of N, O, N2, NO, N2+ and mixtures of these species. The two more efficient approximations, that is, the superposition and multiplication are employed and analyzed.

  6. Organizing Your Hard Disk.

    ERIC Educational Resources Information Center

    Stocker, H. Robert; Hilton, Thomas S. E.

    1991-01-01

    Suggests strategies that make hard disk organization easy and efficient, such as making, changing, and removing directories; grouping files by subject; naming files effectively; backing up efficiently; and using PATH. (JOW)

  7. Hard X-ray emission from the galaxy cluster A2256

    E-print Network

    Fusco-Femiano, R; De Grandi, S; Feretti, L; Giovannini, G; Grandi, P; Malizia, A; Matt, G; Molendi, S

    2000-01-01

    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 4.6sigma 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, not surprisingly given the complex radio morphology of the cluster central region. The spectral index of the hard tail detected by the PDS onboard BeppoSAX is marginally consistent with that expected by the inverse Compton model. A value of ~0.05 microG 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 microG could be present in the central radio halo, likely related to the hard tail detected by ASCA.

  8. Hard X-ray emission from the galaxy cluster A2256

    E-print Network

    R. Fusco-Femiano; D. Dal Fiume; S. De Grandi; L. Feretti; G. Giovannini; P. Grandi; A. Malizia; G. Matt; S. Molendi

    2000-03-13

    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 4.6sigma 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, not surprisingly given the complex radio morphology of the cluster central region. The spectral index of the hard tail detected by the PDS onboard BeppoSAX is marginally consistent with that expected by the inverse Compton model. A value of ~0.05 microG 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 microG could be present in the central radio halo, likely related to the hard tail detected by ASCA.

  9. Olive leaf extract and its main component oleuropein prevent chronic ultraviolet B radiation-induced skin damage and carcinogenesis in hairless mice.

    PubMed

    Kimura, Yoshiyuki; Sumiyoshi, Maho

    2009-11-01

    Chronic exposure to solar UV radiation damages skin, increasing its thickness and reducing its elasticity, and causes skin cancer. Our aim in this study was to examine the effects of an olive leaf extract and its component oleuropein on skin damage and the incidence of skin tumors caused by long-term UVB irradiation in hairless mice. Male hairless mice (5 wk old) were divided into 6 groups, including a non-UVB group, a vehicle-treated UVB group (control), 2 olive leaf extract-treated UVB groups, and 2 oleuropein-treated UVB groups. Five groups were UVB irradiated (36-180 mJ/cm(2)) 3 times each week for 30 wk and skin thickness and elasticity after UVB irradiation were measured every week. Olive leaf extract (300 and 1000 mg/kg) and oleuropein (10 and 25 mg/kg) were administered orally twice daily every day for 30 wk. The extract and oleuropein significantly inhibited increases in skin thickness and reductions in skin elasticity, and skin carcinogenesis and tumor growth. Furthermore, they prevented increases in the expression of matrix metalloproteinase (MMP)-2, MMP-9, and MMP-13 as well as in levels of vascular endothelial growth factor (VEGF) and cyclooxygenase-2 (COX-2) in the skin. Based on histological evaluation, they prevented increases in the expression of Ki-67 and CD31-positive cells induced by the irradiation. These results suggest that the preventative effects of the olive leaf extract and oleuropein on chronic UVB-induced skin damage and carcinogenesis and tumor growth may be due to inhibition of the expression of VEGF, MMP-2, MMP-9, and MMP-13 through a reduction in COX-2 levels. PMID:19776181

  10. A new approach to the equation of state of silicate melts: An application of the theory of hard sphere mixtures

    E-print Network

    A new approach to the equation of state of silicate melts: An application of the theory of hard melts based on the hard sphere mixture model of a liquid. We assign a hard sphere for each cation. The effective size of a hard sphere for each component in silicate melts is determined. The temperature

  11. Dissecting Soft Radiation with Factorization

    E-print Network

    Iain W. Stewart; Frank J. Tackmann; Wouter J. Waalewijn

    2015-02-10

    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 $gg\\to Hg$ and $gq\\to Zq$, but a negative interference contribution for $q\\bar q\\to Z g$. Hence, measuring these dependencies allows one to separate hadronization, soft ISR, and MPI contributions in the data.

  12. 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).

  13. 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.

  14. Recent results on CVD diamond radiation sensors

    Microsoft Academic Search

    P. Weilhammer; W. Adam; C. Bauer; E. Berdermann; F. Bogani; E. Borchi; M. Bruzzi; C. Colledani; J. Conway; W. Dabrowski; P. Delpierre; A. Deneuville; W. Dulinski; R. v. d. Eijk; B. van Eijk; A. Fallou; D. Fish; M. Fried; K. K. Gan; E. Gheeraert; E. Grigoriev; G. Hallewell; R. Hall-Wilton; S. Han; F. Hartjes; J. Hrubec; D. Husson; H. Kagan; D. Kania; J. Kaplon; R. Kass; K. T. Knopfle; M. Krammer; P. F. Manfredi; D. Meier; LeNormand; L. S. Pan; H. Pernegger; M. Pernicka; R. Plano; V. Re; J. L. Riester; S. Roe; Roff; A. Rudge; M. Schieber; S. Schnetzer; S. Sciortino; V. Speziali; H. Stelzer; R. Stone; R. J. Tapper; R. Tesarek; G. B. Thomson; M. Trawick; W. Trischuk; R. Turchetta

    1998-01-01

    CVD diamond radiation sensors are being developed for possible use in trackers in the LHC experiments. The diamond promises to be radiation hard well beyond particle fluences that can be tolerated by Si sensors. Recent results from the RD 42 collaboration on charge collection distance and on radiation hardness of CVD diamond samples will be reported. Measurements with diamond tracking

  15. Model Predictive Tracking Control for a Head-Positioning in a Hard-Disk-Drive

    E-print Network

    Paris-Sud XI, Université de

    /Write (R/W) head of a Hard-Disk-Drive (HDD) servo-system, which is resolved with two control algorithms rejection, and robustness under parameters uncertainties. I. INTRODUCTION Hard-Disc-Drive servo systems have speed. Fig.1 illustrates the main components of a Hard-Disk-Drive. It consists mainly of a Voice-Coil-Motor

  16. AIR LUBRICATION IN HARD DISK DRIVE Mechanics of Contact and Lubrication

    E-print Network

    Müftü, Sinan

    AIR LUBRICATION IN HARD DISK DRIVE Mechanics of Contact been developing very well in the past few years, the HDD (Hard Disk Drive) is still the most important), inside a single-disk hard drive, we can see 3 components: an arm with a read and write head in front

  17. 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,…

  18. Soft Skills, Hard Science

    E-print Network

    Wu, Mingshen

    Soft Skills, Hard Science: A Program to Improve Job Placement of STEM Graduates with Disabilities 2013 Women & Science Conference1 Wednesday, May 22, 13 #12;Why focus on soft skills? What comes to mind rated recent grads on same skills Perception Reality 8 Wednesday, May 22, 13 #12;what are soft skills

  19. Hard (and Soft) Facts.

    ERIC Educational Resources Information Center

    Kennedy, Mike

    1999-01-01

    Provides guidelines to help schools maintain hard floors and carpets, including special areas in schools and colleges that need attention and the elements needed to have a successful carpet-maintenance program. The importance of using heavy equipment to lessen time and effort is explained as are the steps maintenance workers can take to make the…

  20. RADIATION BALANCE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The balance of energy on the earth's surface represents the difference between incoming and outgoing radiation. There are two components in both the incoming and ongoing fractions and are separated by wavelength as shortwave (less than 5 um) and longwave (greater than 5 um). Shortwave radiation or...

  1. Inverse Compton Origin of the Hard X-ray and Soft gamma-ray Emission from the Galactic Ridge

    SciTech Connect

    Porter, Troy A.; Moskalenko, Igor V.; Strong, Andrew W.; Orlando, Elena; Bouchet, Laurent

    2008-09-30

    A recent re-determination of the non-thermal component of the hard X-ray to soft {gamma}-ray emission from the Galactic ridge, using the SPI instrument on the INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL) Observatory, is shown to be well reproduced as inverse-Compton emission from the interstellar medium. Both cosmic-ray primary electrons and secondary electrons and positrons contribute to the emission. The prediction uses the GALPROP model and includes a new calculation of the interstellar radiation field. This may solve a long-standing mystery of the origin of this emission, and potentially opens a new window on Galactic cosmic rays.

  2. Investigation of Solar Flares Using Spectrally, Spatially, and Temporally Resolved Observations in Gamma Rays, Hard X Rays, and Microwaves

    NASA Technical Reports Server (NTRS)

    Crannell, Carol Jo; Oegerle, William (Technical Monitor)

    2003-01-01

    The high-energy components of solar flares radiate at a wide range of wavelengths. We are using spatially, spectrally, and temporally resolved hard X-ray, gamma-ray, and microwave observations of solar flares to investigate flare models and to understand the flare acceleration process. The hard X-ray and gamma-ray observations are obtained with the Reuven Ramaty High-Energy Solar Spectroscopic Imager (RHESSI) spacecraft that was launched on February 5, 2002. The microwave observations are obtained with the Owens Valley Radio Observatory (OVRO), which has been dedicated to daily observations of solar flares in microwaves with a five-element interferometer since June 1992. These studies are expected to yield exciting new insights into the fundamental physics of the flare acceleration processes.

  3. 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.

  4. Local hardness equalization and the principle of maximum hardness.

    PubMed

    Gázquez, José L; Vela, Alberto; Chattaraj, Pratim K

    2013-06-01

    The chemical potential, hardness, and hyperhardnesses equalization principles are used to show that the leading term associated with charge transfer in the total interaction energy among the fragments in which a molecule is divided is directly proportional to minus the hardness of the molecule in its ground state, as established by the principle of maximum hardness. The additional terms in the interaction energy, associated with the changes in the external potential of the fragments, provide explanation for deviations between the point of maximum hardness and the point of minimum energy. It is also found that the dual descriptor plays a very important role in hardness equalization. PMID:23758354

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. Hard metal composition

    DOEpatents

    Sheinberg, H.

    1983-07-26

    A composition of matter having a Rockwell A hardness of at least 85 is formed from a precursor mixture comprising between 3 and 10 wt % boron carbide and the remainder a metal mixture comprising from 70 to 90% 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 and 14 g/cc. The precursor is preferably hot pressed to yield a composition having greater than 100% of theoretical density.

  10. Components of the Goeckerman Regimen

    Microsoft Academic Search

    Mark J. le Vine; H. A. D. White; John A. Parrish

    1979-01-01

    Although application of tar products and subsequent exposure to ultraviolet radiation (the Goeckerman regimen) has repeatedly been demonstrated to be effective therapy for psoriasis, the therapeutic role of each component has remained uncertain. Utilizing the bilateral comparison technique in 30 hospitalized patients with chronic stable plaque-type psoriasis vulgaris, we closely monitored the clinical responses to ultraviolet radiation (Westinghouse fluorescent FS40

  11. 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.

  12. Resolving the Question of IC443'S Hard Emission

    Microsoft Academic Search

    Jonathan Keohane

    1999-01-01

    AXAF is ideally suited to investigate the hard X-ray region of the SNR IC 443, which is currently thought to be X-ray synchrotron radiation as a result of a particular interaction between a shock and a molecular cloud. Alternate explanations, such as a pulsar powered nebula, have still not been completely ruled out. This proposed observation will image the currently

  13. Radiation microscope for SEE testing using GeV ions.

    SciTech Connect

    Doyle, Barney Lee; Knapp, James Arthur; Rossi, Paolo; Hattar, Khalid M.; Vizkelethy, Gyorgy; Brice, David Kenneth; Branson, Janelle V.

    2009-09-01

    Radiation Effects Microscopy is an extremely useful technique in failure analysis of electronic parts used in radiation environment. It also provides much needed support for development of radiation hard components used in spacecraft and nuclear weapons. As the IC manufacturing technology progresses, more and more overlayers are used; therefore, the sensitive region of the part is getting farther and farther from the surface. The thickness of these overlayers is so large today that the traditional microbeams, which are used for REM are unable to reach the sensitive regions. As a result, higher ion beam energies have to be used (> GeV), which are available only at cyclotrons. Since it is extremely complicated to focus these GeV ion beams, a new method has to be developed to perform REM at cyclotrons. We developed a new technique, Ion Photon Emission Microscopy, where instead of focusing the ion beam we use secondary photons emitted from a fluorescence layer on top of the devices being tested to determine the position of the ion hit. By recording this position information in coincidence with an SEE signal we will be able to indentify radiation sensitive regions of modern electronic parts, which will increase the efficiency of radiation hard circuits.

  14. Methane emissions from six crop species exposed to three components of global climate change: temperature, ultraviolet-B radiation and water stress.

    PubMed

    Qaderi, Mirwais M; Reid, David M

    2009-10-01

    We examined the effects of temperature, ultraviolet-B (UVB) radiation and watering regime on aerobic methane (CH(4)) emission from six crops-faba bean, sunflower, pea, canola, barley and wheat. Plants were grown in controlled-environment growth chambers under two temperature regimes (24/20 and 30/26 degrees C), three levels of UVB radiation [0 (zero), 5 (ambient) and 10 (enhanced) kJ m(-2) d(-1)] and two watering regimes (well watered and water stressed). A gas chromatograph with a flame ionization detector was used to measure CH(4) emission rates [ng g(-1) dry weight (DW) h(-1)] from detached fresh leaves of each species and attached leaves of pea plants. Plant growth [stem height, leaf area (LA) and aboveground dry matter (AG biomass)] and gas exchange [net CO(2) assimilation (A(N)), transpiration (E) and water use efficiency (WUE)] were also determined. We found that higher temperature, water stress and UVB radiation at the zero and enhanced levels significantly enhanced CH(4) emissions. Crop species varied in CH(4) emission, which was highest for pea and lowest for barley. Higher temperature and water stress reduced all growth parameters, whereas ambient and enhanced UVB decreased stem height but increased LA and AG biomass. Higher temperature decreased A(N) and WUE but increased E, whereas water stress decreased A(N) but increased E and WUE. Zero and enhanced UVB reduced A(N) and E. Growth and gas exchange varied with species. Overall, CH(4) emission was negatively correlated with stem height and AG biomass. We conclude that CH(4) emissions may increase under climatic stress conditions and this extra source might contribute to the 'greenhouse effect'. PMID:19678898

  15. Synchrotron radiation total reflection X-ray fluorescence and energy dispersive X-ray fluorescence analysis on AP1™ films applied to the analysis of trace elements in metal alloys for the construction of nuclear reactor core components: a comparison

    NASA Astrophysics Data System (ADS)

    Pepponi, G.; Wobrauschek, P.; Hegedüs, F.; Streli, C.; Zöger, N.; Jokubonis, C.; Falkenberg, G.; Grimmer, H.

    2001-11-01

    Synchrotron radiation induced total reflection X-ray fluorescence and conventional 45° energy dispersive X-ray fluorescence analysis using a 150-nm-thick AP1™ film as sample carrier have been exploited for the elemental analysis of traces in alloys used for the construction of reactor core components of nuclear power plants. Both techniques are well suited for the analysis since they require a low amount of sample (?l), important on one hand because of the limited disposal and on the other hand because of its high specific activity. The methods provide a very low background due to the total reflection phenomenon in TXRF and the thin AP1™ film sample support, respectively. The employment of synchrotron radiation was necessary since there are no laboratory sources which can deliver a collimated beam of the energy and intensity needed to excite the K-shell of the rare earth elements, allowing the achievement of minimum detection limits relevant for the proposed purpose (ng/g range). Moreover, the linear polarization of synchrotron radiation combined with a side-looking detection geometry manages to reduce the scattering due to the remaining matrix of the analyzed samples. Detection limits for Nb and for some of the rare earth elements (pg range for absolute detection limits and ng-?g/g range for concentration detection limits) obtained with the two techniques are presented and the two approaches are compared.

  16. 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.

  17. PUBLISHED VERSION Study of runaway electrons with Hard X-ray spectrometry of tokamak plasmas

    E-print Network

    induced during the current quench phase may produce a large number of runaway electrons with energies electrons using dosimetry of hard x-ray radiations in Damavand tokamak Rev. Sci. Instrum. 85, 053509 (2014 current and its profile during disruption. Keywords: Physics of Plasma, Hard X-Rays, Runaway Electrons

  18. Effects of UV radiation on the growth, photosynthetic and photoprotective components, and reproduction of the Caribbean shallow-water coral Porites furcata

    NASA Astrophysics Data System (ADS)

    Torres-Pérez, J. L.; Armstrong, R. A.

    2012-12-01

    Shallow reef corals can frequently be subjected to high doses of ultraviolet radiation [280-400 nm (UVR)] and have developed mechanisms to cope with this. Nevertheless, slight changes in this stressor may impact their physiology and ultimately their survival. Here, we present results on the effects of artificially enhanced UVR on the growth, reproduction, production of photosynthetic pigments and photoprotective compounds of the Caribbean shallow-water branching coral Porites furcata. Corals were randomly located in one of the three different treatments: normal photosynthetically active radiation (PAR) + UVR; normal PAR+ enhanced UVR; normal PAR+ depleted UVR. Growth rates were measured using the Alizarin red staining method, photosynthetic pigments as well as mycosporine-like amino acids (MAAs) were quantified through high-performance liquid chromatography, and fecundity was estimated after histological analyses. Growth and photosynthetic pigment concentration were negatively correlated with increased UVR, compared to controls exposed to normal UVR. A significant increase in MAAs was also found in colonies under enhanced UVR. Based on their respective concentrations, the primary mycosporine-glycine (?max = 310 nm) and shinorine (?max = 333 nm) are the main contributors to UVR absorption in this species, while the levels of the secondary MAA palythine (?max = 320 nm) tripled toward the end of the 128 days of the experimental period. While several physical factors may influence reef coral physiology, the results suggest that slight increases in UVR can debilitate the skeletal constitution and severely reduce the fecundity of corals living in shallow waters.

  19. Evaluation of aging degradation of structural components

    SciTech Connect

    Chopra, O.K.; Shack, W.J.

    1992-03-01

    Irradiation embrittlement of the neutron shield tank (NST) A212 Grade B steel from the Shippingport reactor, as well as thermal embrittlement of CF-8 cast stainless steel components from the Shippingport and KRB reactors, has been characterized. Increases in Charpy transition temperature (CTT), yield stress, and hardness of the NST material in the low-temperature low-flux environment are consistent with the test reactor data for irradiations at < 232{degrees}C. The shift in CTT is not as severe as that observed in surveillance samples from the High Flux Isotope Reactor (HFIR): however, it shows very good agreement with the results for HFIR A212-B steel irradiated in the Oak Ridge Research Reactor. The results indicate that fluence rate has not effect on radiation embrittlement at rates as low as 2 {times} 10{sup 8} n/cm{sup 2}{center_dot}s at the low operating temperature of the Shippingport NST, i.e., 55{degrees}C. This suggest that radiation damage in Shippingport NST and HFIR surveillance samples may be different because of the neutron spectra and/or Cu and Ni content of the two materials. Cast stainless steel components show relatively modest decreases in fracture toughness and Charpy-impact properties and a small increase in tensile strength. Correlations for estimating mechanical properties of cast stainless steels predict accurate or slightly conservative values for Charpy-impact energy, tensile flow stress, fracture toughness J-R curve, and J{sub IC} of the materials. The kinetics of thermal embrittlement and degree of embrittlement at saturation, i.e., the minimum impact energy achieved after long-term aging, were established from materials that were aged further in the laboratory. The results were consistent with the estimates. The correlations successfully predict the mechanical properties of the Ringhals 2 reactor hot- and crossover-leg elbows (CF-8M steel) after service of {approx}15 y.

  20. Evaluation of aging degradation of structural components

    SciTech Connect

    Chopra, O.K.; Shack, W.J.

    1992-03-01

    Irradiation embrittlement of the neutron shield tank (NST) A212 Grade B steel from the Shippingport reactor, as well as thermal embrittlement of CF-8 cast stainless steel components from the Shippingport and KRB reactors, has been characterized. Increases in Charpy transition temperature (CTT), yield stress, and hardness of the NST material in the low-temperature low-flux environment are consistent with the test reactor data for irradiations at < 232{degrees}C. The shift in CTT is not as severe as that observed in surveillance samples from the High Flux Isotope Reactor (HFIR): however, it shows very good agreement with the results for HFIR A212-B steel irradiated in the Oak Ridge Research Reactor. The results indicate that fluence rate has not effect on radiation embrittlement at rates as low as 2 {times} 10{sup 8} n/cm{sup 2}{center dot}s at the low operating temperature of the Shippingport NST, i.e., 55{degrees}C. This suggest that radiation damage in Shippingport NST and HFIR surveillance samples may be different because of the neutron spectra and/or Cu and Ni content of the two materials. Cast stainless steel components show relatively modest decreases in fracture toughness and Charpy-impact properties and a small increase in tensile strength. Correlations for estimating mechanical properties of cast stainless steels predict accurate or slightly conservative values for Charpy-impact energy, tensile flow stress, fracture toughness J-R curve, and J{sub IC} of the materials. The kinetics of thermal embrittlement and degree of embrittlement at saturation, i.e., the minimum impact energy achieved after long-term aging, were established from materials that were aged further in the laboratory. The results were consistent with the estimates. The correlations successfully predict the mechanical properties of the Ringhals 2 reactor hot- and crossover-leg elbows (CF-8M steel) after service of {approx}15 y.

  1. Electronic Components

    NSDL National Science Digital Library

    Lesurf, Jim

    This page from Jim Lesurf of the University of St. Andrews explains common electronic components in an easily understood format. Resistors, capacitors, diodes, inductors and more are explained here. The difference between passive and active components is also explained. Information about conductors and semiconductors is provided as well.

  2. Crystalline assembly of hard polyhedra via directional entropic forces

    NASA Astrophysics Data System (ADS)

    Damasceno, Pablo F.; Engel, Michael; Glotzer, Sharon C.

    2012-02-01

    Entropic forces are effective forces that result from a system's statistical tendency to increase its entropy. Hard rods and disks spontaneously align and can assemble into layers and columns if those structures increase the configurational space available to the particles. Hard spheres, cubes and even tetrahedra order for the same reason. Here we extend those findings by showing that hard polyhedra can self-assemble into a variety of complex phases, most of them never before reported in systems of single-component hard particles. The role of shape and directional entropic forces in stabilizing these structures will be discussed. Our results suggest new possibilities for self-assembling complex target structures from colloidal building blocks. [4pt] [1] Damasceno, PF; Engel, M; Glotzer, SC. arXiv:1109.1323v1

  3. Maximum Chemical and Physical Hardness

    Microsoft Academic Search

    Ralph G. Pearson

    1999-01-01

    Density functional theory (DFT) is briefly reviewed, especially concepts such as the electronic chemical potential and the hardness of the electron density function. There is much evidence, and a mathematical proof, that this chemical hardness is a maximum for an equilibrium system. The proof is based on a combination of statistical mechanics, the fluctuation-dissipation theorem, and correlation functions. In MO

  4. 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…

  5. Subjective hardness of compliant materials

    Microsoft Academic Search

    Roland Harper; S. S. Stevens

    1964-01-01

    The apparent hardness and softness of nine samples of compliant materials were scaled by direct magnitude estimation and by cross-modal matches to the apparent force exerted on a hand dynamometer and a finger dynamometer, and to the loudness of a band of white noise. The physical hardness (force\\/indentation) of the compliant specimens covered a range of more than 100 to

  6. A first-principles approach to total-dose hardness assurance

    Microsoft Academic Search

    Fleetwood

    1995-01-01

    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

  7. Multifactorial Resistance of Bacillus subtilis Spores to High-Energy Proton Radiation: Role of Spore Structural Components and the Homologous Recombination and Non-Homologous End Joining DNA Repair Pathways

    PubMed Central

    Reitz, Günther; Li, Zuofeng; Klein, Stuart; Nicholson, Wayne L.

    2012-01-01

    Abstract The space environment contains high-energy charged particles (e.g., protons, neutrons, electrons, ?-particles, heavy ions) emitted by the Sun and galactic sources or trapped in the radiation belts. Protons constitute the majority (87%) of high-energy charged particles. Spores of Bacillus species are one of the model systems used for astro- and radiobiological studies. In this study, spores of different Bacillus subtilis strains were used to study the effects of high energetic proton irradiation on spore survival. Spores of the wild-type B. subtilis strain [mutants deficient in the homologous recombination (HR) and non-homologous end joining (NHEJ) DNA repair pathways and mutants deficient in various spore structural components such as dipicolinic acid (DPA), ?/?-type small, acid-soluble spore protein (SASP) formation, spore coats, pigmentation, or spore core water content] were irradiated as air-dried multilayers on spacecraft-qualified aluminum coupons with 218 MeV protons [with a linear energy transfer (LET) of 0.4?keV/?m] to various final doses up to 2500 Gy. Spores deficient in NHEJ- and HR-mediated DNA repair were significantly more sensitive to proton radiation than wild-type spores, indicating that both HR and NHEJ DNA repair pathways are needed for spore survival. Spores lacking DPA, ?/?-type SASP, or with increased core water content were also significantly more sensitive to proton radiation, whereas the resistance of spores lacking pigmentation or spore coats was essentially identical to that of the wild-type spores. Our results indicate that ?/?-type SASP, core water content, and DPA play an important role in spore resistance to high-energy proton irradiation, suggesting their essential function as radioprotectants of the spore interior. Key Words: Bacillus—Spores—DNA repair—Protection—High-energy proton radiation. Astrobiology 12, 1069–1077. PMID:23088412

  8. Cyclic strength of hard metals

    SciTech Connect

    Sereda, N.N.; Gerikhanov, A.K.; Koval'chenko, M.S.; Pedanov, L.G.; Tsyban', V.A.

    1986-02-01

    The authors study the strength of hard-metal specimens and structural elements under conditions of cyclic loading since many elements of processing plants, equipment, and machines are made of hard metals. Fatigue tests were conducted on KTS-1N, KTSL-1, and KTNKh-70 materials, which are titanium carbide hard metals cemented with nickel-molybdenum, nickelcobalt-chromium, and nickel-chromium alloys, respectively. As a basis of comparison, the standard VK-15 (WC+15% Co) alloy was used. Some key physicomechanical characteristics of the materials investigated are presented. On time bases not exceeding 10/sup 6/ cycles, titanium carbide hard metals are comparable in fatigue resistance to the standard tungstencontaining hard metals.

  9. Charpy Impact Energy and Microindentation Hardness of 60-NITINOL

    NASA Technical Reports Server (NTRS)

    Stanford, Malcolm K.

    2012-01-01

    60-NITINOL (60 wt.% Ni 40 wt.% Ti) is being studied as a material for advanced aerospace components. The Charpy impact energy and microindentation hardness has been studied for this material, fabricated by vacuum induction skull melting (casting) and by hot isostatic pressing. Test specimens were prepared in various hardened and annealed heat treatment conditions. The average impact energy ranged from 0.33 to 0.49J for the hardened specimens while the annealed specimens had impact energies ranging from 0.89 to 1.18J. The average hardness values of the hardened specimens ranged from 590 to 676 HV while that of the annealed specimens ranged from 298 to 366 HV, suggesting an inverse relationship between impact energy and hardness. These results are expected to provide guidance in the selection of heat treatment processes for the design of mechanical components.

  10. Hardness and fracture toughness of moissanite

    Microsoft Academic Search

    J. Qian; L. L. Daemen; Y. Zhao

    2005-01-01

    Disparities prevail among the reported hardness and fracture toughness values for hard and brittle materials. A better understanding of the physical nature of hardness and fracture toughness and a standardized technique for reliable measurements of these quantities is urgently needed. We strongly recommend the use of the measured hardness after the bend in the hardness versus load (H?FLoad) curve, when

  11. Campus Access for Students Who Are Hard of Hearing.

    ERIC Educational Resources Information Center

    Warick, Ruth

    A survey of 160 hard of hearing Canadian youth found that educational access was their single highest priority. Supports used by youth in postsecondary education included personal Frequency Modulation (FM) systems, notetaking, oral interpreting, sign interpreting, and tutors. Four components of access to education are identified, with particular…

  12. Globalization of Production: Insights from the Hard Disk Drive Industry

    Microsoft Academic Search

    Peter Gourevitch; Roger Bohn; David McKendrick

    2000-01-01

    Rapid change in the geographical location of production raises important questions regarding the welfare, development potential, and competitive position of different countries and regions. This paper explores in detail the geography of economic activity in a specific industry, the hard disk drive (HDD) component of the computer industry. Firms in the HDD industry are breaking the production system into ever

  13. 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 ...

  14. 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 ...

  15. Stationary radiation of objects with scattering media

    Microsoft Academic Search

    Inna A Vasileva

    2001-01-01

    The radiation observed inside or outside a stationary radiator with a scattering medium is a sum of components, each being determined by, first, the primary radiation from some part of the radiator and, second, the probability of this radiation reaching the region where it is observed. In this review, general and rather simple relations between these components are discussed. These

  16. Hard X-ray and Gamma-ray Emission Induced by Ultra-High Energy Protons in Cluster Accretion Shocks

    E-print Network

    Susumu Inoue; Felix A. Aharonian; Naoshi Sugiyama

    2005-06-05

    All sufficiently massive clusters of galaxies are expected to be surrounded by strong accretion shocks, where protons can be accelerated to $\\sim 10^{18}$-$10^{19}$ eV under plausible conditions. Such protons interact with the cosmic microwave background and efficiently produce very high energy electron-positron pairs, which then radiate synchrotron and inverse Compton emission, peaking respectively at hard X-ray and TeV gamma-ray energies. Characterized by hard spectra (photon indices $\\sim 1.5$) and spatial distribution tracing the accretion shock, these can dominate over other nonthermal components depending on the shock magnetic field. HESS and other Cerenkov telescopes may detect the TeV emission from nearby clusters, notwithstanding its extended nature. The hard X-rays may be observable by future imaging facilities such as NeXT, and possibly also by ASTRO-E2/HXD. Such detections will not only provide a clear signature of ultra-high energy proton acceleration, but also an important probe of the accretion shock itself as well as magnetic fields in the outermost regions of clusters.

  17. Extended hard-X-ray emission in the inner few parsecs of the Galaxy.

    PubMed

    Perez, Kerstin; Hailey, Charles J; Bauer, Franz E; Krivonos, Roman A; Mori, Kaya; Baganoff, Frederick K; Barrière, Nicolas M; Boggs, Steven E; Christensen, Finn E; Craig, William W; Grefenstette, Brian W; Grindlay, Jonathan E; Harrison, Fiona A; Hong, Jaesub; Madsen, Kristin K; Nynka, Melania; Stern, Daniel; Tomsick, John A; Wik, Daniel R; Zhang, Shuo; Zhang, William W; Zoglauer, Andreas

    2015-04-30

    The Galactic Centre hosts a puzzling stellar population in its inner few parsecs, with a high abundance of surprisingly young, relatively massive stars bound within the deep potential well of the central supermassive black hole, Sagittarius A* (ref. 1). Previous studies suggest that the population of objects emitting soft X-rays (less than 10 kiloelectronvolts) within the surrounding hundreds of parsecs, as well as the population responsible for unresolved X-ray emission extending along the Galactic plane, is dominated by accreting white dwarf systems. Observations of diffuse hard-X-ray (more than 10 kiloelectronvolts) emission in the inner 10 parsecs, however, have been hampered by the limited spatial resolution of previous instruments. Here we report the presence of a distinct hard-X-ray component within the central 4 × 8 parsecs, as revealed by subarcminute-resolution images in the 20-40 kiloelectronvolt range. This emission is more sharply peaked towards the Galactic Centre than is the surface brightness of the soft-X-ray population. This could indicate a significantly more massive population of accreting white dwarfs, large populations of low-mass X-ray binaries or millisecond pulsars, or particle outflows interacting with the surrounding radiation field, dense molecular material or magnetic fields. However, all these interpretations pose significant challenges to our understanding of stellar evolution, binary formation, and cosmic-ray production in the Galactic Centre. PMID:25925477

  18. Extended hard-X-ray emission in the inner few parsecs of the Galaxy

    NASA Astrophysics Data System (ADS)

    Perez, Kerstin; Hailey, Charles J.; Bauer, Franz E.; Krivonos, Roman A.; Mori, Kaya; Baganoff, Frederick K.; Barrière, Nicolas M.; Boggs, Steven E.; Christensen, Finn E.; Craig, William W.; Grefenstette, Brian W.; Grindlay, Jonathan E.; Harrison, Fiona A.; Hong, Jaesub; Madsen, Kristin K.; Nynka, Melania; Stern, Daniel; Tomsick, John A.; Wik, Daniel R.; Zhang, Shuo; Zhang, William W.; Zoglauer, Andreas

    2015-04-01

    The Galactic Centre hosts a puzzling stellar population in its inner few parsecs, with a high abundance of surprisingly young, relatively massive stars bound within the deep potential well of the central supermassive black hole, Sagittarius A* (ref. 1). Previous studies suggest that the population of objects emitting soft X-rays (less than 10 kiloelectronvolts) within the surrounding hundreds of parsecs, as well as the population responsible for unresolved X-ray emission extending along the Galactic plane, is dominated by accreting white dwarf systems. Observations of diffuse hard-X-ray (more than 10 kiloelectronvolts) emission in the inner 10 parsecs, however, have been hampered by the limited spatial resolution of previous instruments. Here we report the presence of a distinct hard-X-ray component within the central 4 × 8 parsecs, as revealed by subarcminute-resolution images in the 20-40 kiloelectronvolt range. This emission is more sharply peaked towards the Galactic Centre than is the surface brightness of the soft-X-ray population. This could indicate a significantly more massive population of accreting white dwarfs, large populations of low-mass X-ray binaries or millisecond pulsars, or particle outflows interacting with the surrounding radiation field, dense molecular material or magnetic fields. However, all these interpretations pose significant challenges to our understanding of stellar evolution, binary formation, and cosmic-ray production in the Galactic Centre.

  19. Hard-on-Hard Total Hip Impingement Causes Extreme Contact Stress Concentrations

    PubMed Central

    Elkins, Jacob M.; O’Brien, Megan K.; Stroud, Nicholas J.; Pedersen, Douglas R.; Callaghan, John J.

    2010-01-01

    Background Impingement events, in addition to their role immediately proximate to frank dislocation, hold the potential to damage new-generation hard-on-hard bearings as a result of the relatively unforgiving nature of the materials and designs. Because of the higher stiffness and tighter design tolerances of metal-on-metal and ceramic implants, surgical positioning plausibly has become even more important. Questions/purposes We asked (1) whether, and under what cup orientation conditions, hard-on-hard impingements might challenge implant material failure strength; and (2) whether particle generation propensity at impingement and egress sites would show similar dependence on cup orientation. Methods Realistic computational simulations were enabled by multistage finite element analyses, addressing both global construct motion and loading, and focal stress concentrations at neck impingement and rim egress sites. The global model, validated by a cadaveric simulation in a servohydraulic hip simulator, included both hardware components and advanced anisotropic capsule characterization. Parametric computational runs explored the effect of cup orientation for both ceramic-on-ceramic and metal-on-metal bearing couples for two distinct motion sequences associated with dislocation. Results Stress concentrations from impingement increased nearly linearly with increased cup tilt and with cup anteversion. In some situations, peak values of stress approached or exceeded 1 GPa, levels challenging the yield strength of cobalt-chromium implants, and potentially the fracture strength of ceramics. The tendency for impingement events to generate debris, indexed in terms of a new scraping severity metric, showed orientation dependences similar to that for bulk material failure. Conclusions Damage propensity arising from impingement events in hard total hip bearings is highly orientation-dependent. PMID:20953853

  20. Simulation of the binary hard-sphere crystal/melt interface

    E-print Network

    Davidchack, Ruslan L.; Laird, Brian Bostian

    1996-12-01

    We report results of molecular-dynamics simulations on a planar binary hard-sphere disordered facecentered-cubic [100] crystal/melt interface. From the analysis of the single-particle density and diffusion profiles for the separate components...

  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. Long-Term Variability of AGN at Hard X-Rays

    NASA Technical Reports Server (NTRS)

    Soldi, S.; Beckmann, V.; Baumgartner W. H.; Ponti, G.; Shrader, C. R.; Lubinski, P.; Krimm, H. A.; Mattana, F.; Tueller, J.

    2013-01-01

    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 a 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 on the first 9 months of BAT data, we study the amplitude of the variations, and their dependence on sub-class and on energy, for a sample of 110 radio quiet and radio loud AGN selected from the BAT 58-month survey. About 80 of the AGN in the sample are found to exhibit significant variability on months to years time scales, radio loud sources being the most variable. The amplitude of the variations and their energy dependence are incompatible with variability being driven at hard X-rays by changes of the absorption column density. In general, the variations in the 14-24 and 35-100 keV bands are well correlated, suggesting a common origin of 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 month time scale. In addition, sources with harder spectra are found to be more variable than softer ones. These properties are generally consistent with a variable power law continuum, in flux and shape, 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).

  4. 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 ...

  5. 4H-SiC and novel SI GaAs-based M-S-M radiation hard photodetectors applicable in UV, EUV, and soft x-ray detection: design, technology, and performance testing

    NASA Astrophysics Data System (ADS)

    Dubecký, František; Ková?, Jaroslav; Ková?, Jaroslav; Zatko, Bohumír.; Oswald, Jirí; Hubík, Pavel; Kindl, Dobroslav; Vanko, Gabriel; Gombia, Enos; Ferrari, Claudio; Bohá?ek, Pavol; Šagátová, Andrea; Ne?as, Vladimír.; Seká?ová, Mária

    2013-05-01

    Work reports on results in development of 4H-SiC and semi-insulating (SI) GaAs large area surface barrier detectors. 4H-SiC detectors are based on high purity liquid phase epitaxy layer with the Schottky barrier contact formed by semitransparent Ni. SI GaAs detectors are based on bulk undoped material using novel electrode metallization with improved sensitivity in UV and soft X-ray ranges. The novel detector use semitransparent low work function Mg metal contact giving a new electronic characteristic of the junction. Electrical characteristics of the diodes, photocurrent measurements and pulse height spectra of gamma and low energy X-rays using the 241Am source, are presented. Improvement of 4H-SiC detector resistance to gamma radiation and neutron fluency is demonstrated. Problems with design and application of related ultra-low noise electronics are introduced and discussed.

  6. The virial coefficients of hard hypersphere binary mixtures

    NASA Astrophysics Data System (ADS)

    Enciso, E.; Almarza, N. G.; Gonzalez, M. A.; Bermejo, F. J.

    The third, fourth and fifth virial coefficients of hard hypersphere binary mixtures with dimensionality d = 4, 5 have been calculated for size ratios R ?0.1, R ? ?22 / ?11 , where ? ii is the diameter of component i . The composition independent partial virial coefficients have been evaluated by Monte Carlo integration of the corresponding Mayer modified star diagrams. The results are compared with the predictions of Santos, S., Yuste, S. B., and Lopez de Haro, M., 1999, Molec. Phys ., 96 , 1 of the equation of state of a multicomponent mixture of hard hyperspheres, and the good agreement gives strong support to the validity of that recipe.

  7. An Apparent Hard X-ray Decline of CH Cygni

    E-print Network

    Koji Mukai; Manabu Ishida; Caroline Kilbourne; Hideyuki Mori; Yukikatsu Terada; Kai-Wing Chan; Yang Soong

    2006-09-08

    CH Cygni is a symbiotic star consisting of an M giant and an accreting white dwarf, which is known to be a highly variable X-ray source with a complex, two-component, spectra. Here we report on two Suzaku observations of CH Cyg, taken in 2006 January and May, during which the system was seen to be in a soft X-ray bright, hard X-ray faint state. Based on the extraordinary strength of the 6.4 keV fluorescent Fe K-alpha line, we show that the hard X-rays observed with Suzaku are dominated by scattering.

  8. Preliminary ground test radiation results of NASA's MPTB dual-rate 1773 experiment

    NASA Astrophysics Data System (ADS)

    LaBel, Kenneth A.; Flanegan, Mark C.; Jackson, George L.; Hawkins, Donald K.; Dale, Cheryl J.; Marshall, Paul W.; Johnson, Donald; Seidleck, Christina; Bonebright, Rodney K.; Kim, Jae H.; Chan, Eric Y.; Bocek, Thomas M.; Bartholet, William G.

    1996-10-01

    NASA Goddard Space Flight Center (GSFC) along with the Naval Research Laboratory (NRL) has been at the forefront of the space community in terms of the use of fiber optic data busses and links in the space radiation environment. Previously, we have described the ground radiation test program of the small explorer data system (SEDS) 1773 1 Mbps fiber optic data bus (FODB), as well as its associated in- flight space radiation-induced performance. Further work has also been presented covering higher speed photonic components utilizing III-V materials. Because of the success of the SEDS 1773 FODB coupled with the radiation testing of III-V devices, a second generation FODB capable of both 1 Mbps and 20 Mbps operation is being developed for spaceflight utilization. We present herein preliminary ground test radiation results of hybrid transceiver devices manufactured by Boeing Space Systems that perform the electro-optic and opto-electric translations in support of this medium rate FODB, the AS1773 bus. These devices, designed to be radiation hard (or rad hard), will be flying on NRL's Microelectronics and Photonics Testbed (MPTB) payload as a NASA experiment. This experiment is described in detail elsewhere in this proceedings.

  9. POP Frameworks: Amortizing the Cost of Using Applications as Components

    Microsoft Academic Search

    David Coppit; Kevin J. Sullivan

    Package-oriented programming (POP) is a promising approach to component-based software design. POP treats suites of mass - market application packages as component libraries. Their stan- dardized architectures, programmability, interoperability, rich orthogonal functions, and low cost make them attractive candi- dates as components. However, they also have characteristics that make it hard and risky to find workable designs. Each de- signer

  10. 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.

  11. 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

  12. The Coma Cluster hard X-ray spectrum revisited: still no evidence for a hard tail

    E-print Network

    M. Rossetti; S. Molendi

    2007-02-15

    In this note, we reply to Fusco-Femiano et al. (2004) and Fusco-Femiano et al. (2006), who cast doubts on our analysis of the PDS observations of the Coma Cluster which we describe in Rossetti & Molendi (2004). We discuss the main issues in Fusco-Femiano et al. (2006) and we confirm that the available data do not allow to firmly establish the presence of a non-thermal component in the hard X-ray spectrum of the Coma cluster.

  13. 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.

  14. Deglaciation mechanisms for a paleoproterozoic hard snowball

    NASA Astrophysics Data System (ADS)

    Pierrehumbert, R. T.; Mitchell, J.; Levine, X.

    2006-05-01

    Our earlier work on the Neoproterozoic hard snowball climate indicated that very high CO2 thresholds would be needed for deglaciation, owing to lapse rate feedbacks and snow cover effects that are not represented in standard energy balance models. We examine here a range of similar issues for the Paleoproterozoic, at which time the Sun was still fainter, but the geothermal heat flux was larger. The warmest position in a hard snowball climate occurs in the Summer subtropics, and we have found that many salient features of the climate there can be reproduced using a radiative-convective model, since the lateral heat fluxes are weak in this case. We show that the radiative-convective model reproduces the low tropopause height that leads to a weak greenhouse effect in full GCM simulations. We exploit this simplification to explore the role of surface boundary layer fluxes and atmospheric solar heating in determining the CO2 threshold for deglaciation. This technique is used to estimate deglaciation thresholds for the Paleoproterozoic. Cloud feedbacks remain a major source of uncertainty, but we remark that the shallow depth reached by convection makes extensive high cloud cover unlikely. We discuss also two aspects of ice dynamics that may be relevant to Paleoproterozoic climate and chemistry. The first is the "thin ice" solution proposed by McKay, shot down by Warren et al, but recently tentatively reinvigorated by Pollard and Kasting in the context of an energy balance model. We discuss the problem of whether such solutions are compatible with the lateral heat flux, vertical sensible heat transfer, and snow cover yielded by full GCM simulations, taking cognizance also of the higher geothermal heat flux estimated for the Paleoproterozoic. Finally, we provide some estimates of the mean age of "sea glacier" ice in Paleoproterozoic conditions, which is relevant to the prospects for a H2O2-based oxygenation theory proposed recently by Liang et al.

  15. Component separations.

    PubMed

    Heller, Lior; McNichols, Colton H; Ramirez, Oscar M

    2012-02-01

    Component separation is a technique used to provide adequate coverage for midline abdominal wall defects such as a large ventral hernia. This surgical technique is based on subcutaneous lateral dissection, fasciotomy lateral to the rectus abdominis muscle, and dissection on the plane between external and internal oblique muscles with medial advancement of the block that includes the rectus muscle and its fascia. This release allows for medial advancement of the fascia and closure of up to 20-cm wide defects in the midline area. Since its original description, components separation technique underwent multiple modifications with the ultimate goal to decrease the morbidity associated with the traditional procedure. The extensive subcutaneous lateral dissection had been associated with ischemia of the midline skin edges, wound dehiscence, infection, and seroma. Although the current trend is to proceed with minimally invasive component separation and to reinforce the fascia with mesh, the basic principles of the techniques as described by Ramirez et al in 1990 have not changed over the years. Surgeons who deal with the management of abdominal wall defects are highly encouraged to include this technique in their collection of treatment options. PMID:23372455

  16. Radiation Protection and Licensing FNAL Radiation Physics Team

    E-print Network

    McDonald, Kirk

    Radiation Protection and Licensing K. Vaziri, FNAL Radiation Physics Team Proton Accelerators, 2012 #12;January 13, 2012 Radiation Protection and Licensing 2 Radiation Protection and Licensing 1 5. Tritium control and ground-water protection 6. Radioactive component storage 7. Repair

  17. Life-cycle cost trade studies for hardness assurance

    Microsoft Academic Search

    Douglas G. Millward

    1996-01-01

    Based on hardness assurance (HA) cost trade studies conducted on a low-cost\\/high-volume tactical military system with moderate radiation environments, conventional strategies for design hardening and HA can result in higher life-cycle costs (LCC) than alternate approaches. The trade studies used variables designed to investigate LCC as a function of several critical parameters, including semiconductor procurement option, system quantity, HA testing

  18. Depletion effects in a mixture of hard and attractive colloids.

    PubMed

    Lajovic, A; Tomsic, M; Jamnik, A

    2009-03-14

    Monte Carlo simulation and theory were used to study the potential of mean force (PMF) between a pair of big colloidal (solute) particles suspended in a sea of smaller particles (solvent) interacting via Baxter's sticky hard sphere (SHS) potential. Simulation results were obtained by applying a special simulation technique developed for sampling the hard sphere collision force, while the theoretical predictions were calculated from the analytic solution of the Percus-Yevick/Ornstein-Zernike integral equation for spatial correlations in a two-component mixture at vanishing solute concentration. Both theory and simulation revealed oscillations of the solute-solute PMF with a period equal to the diameter of the solvent molecules. Further, the attractive PMF between solute particles in the SHS fluid decays slower than in a hard sphere solvent. Upon increasing the strength of attraction (stickiness) between the molecules of solvent, these oscillations gradually disappear, the PMF becoming long ranged and attractive at all separations. PMID:19292517

  19. Multicomponent fluids of hard hyperspheres in odd dimensions.

    PubMed

    Rohrmann, René D; Santos, Andrés

    2011-01-01

    Mixtures of hard hyperspheres in odd-space dimensionalities are studied with an analytical approximation method. This technique is based on the so-called rational function approximation and provides a procedure for evaluating equations of state, structure factors, radial distribution functions, and direct correlation functions of additive mixtures of hard hyperspheres with any number of components and in arbitrary odd-dimension space. The method gives the exact solution of the Ornstein-Zernike equation coupled with the Percus-Yevick closure, thus, extending the solution for hard-sphere mixtures [J. L. Lebowitz, Phys. Rev. 133, A895 (1964)] to arbitrary odd dimensions. Explicit evaluations for binary mixtures in five dimensions are performed. The results are compared with computer simulations, and a good agreement is found. PMID:21405686

  20. Mass loss from inhomogeneous hot star winds. III. An effective-opacity formalism for line radiative transfer in accelerating, clumped two-component media, and first results on theory and diagnostics

    NASA Astrophysics Data System (ADS)

    Sundqvist, J. O.; Puls, J.; Owocki, S. P.

    2014-08-01

    Aims: We provide a fast and easy-to-use formalism for treating the reduction in effective opacity associated with optically thick clumps in an accelerating two-component medium. Methods: We develop and benchmark effective-opacity laws for continuum and line radiative transfer that bridge the limits of optically thin and thick clumps. We then use this formalism to i) design a simple method for modeling and analyzing UV wind resonance lines in hot, massive stars, and ii) derive simple correction factors to the line force driving the outflows of such stars. Results: Using a vorosity-modified Sobolev with exact integration (vmSEI) method, we show that, for a given ionization factor, UV resonance doublets may be used to analytically predict the upward corrections in empirically inferred mass-loss rates associated with porosity in velocity space (a.k.a. velocity-porosity, or vorosity). However, we also show the presence of a solution degeneracy: in a two-component clumped wind with given inter-clump medium density, there are always two different solutions producing the same synthetic doublet profile. We demonstrate this by application to SiIV and PV in B and O supergiants and derive, for an inter-clump density set to 1% of the mean density, upward empirical mass-loss corrections of typically factors of either ~5 or ~50, depending on which of the two solutions is chosen. Overall, our results indicate that this solution dichotomy severely limits the use of UV resonance lines as direct mass-loss indicators in current diagnostic models of clumped hot stellar winds. We next apply the effective line-opacity formalism to the standard CAK theory of line-driven winds. A simple vorosity correction factor to the CAK line force is derived, which for normalized velocity filling factor fvel simply scales as fvel?, where ? is the slope of the CAK line-strength distribution function. By analytic and numerical hydrodynamics calculations, we further show that in cases where vorosity is important at the critical point setting the mass-loss rate, the reduced line force leads to a lower theoretical mass loss, by simply a factor fvel. On the other hand, if vorosity is important only above this critical point, the predicted mass loss is not affected, but the wind terminal speed is reduced, by a factor scaling as fvel?/(2-2?). This shows that porosity in velocity space can have a significant impact not only on the diagnostics, but also on the dynamics and theory of radiatively driven winds.

  1. Universal Hard-Loop Actions

    E-print Network

    Czajka, Alina

    2015-01-01

    The effective actions of gauge bosons, fermions and scalars, which are obtained within the hard-loop approximation, are shown to have unique forms for a whole class of gauge theories including QED, scalar QED, super QED, pure Yang-Mills, QCD, super Yang-Mills. The universality occurs irrespective of a field content of each theory and of variety of specific interactions. Consequently, the long-wavelength or semiclassical features of plasma systems governed by these theories such as collective excitations are almost identical. An origin of the universality, which holds within the limits of applicability of the hard-loop approach, is discussed.

  2. Universal Hard-Loop Actions

    E-print Network

    Alina Czajka; Stanislaw Mrowczynski

    2015-05-29

    The effective actions of gauge bosons, fermions and scalars, which are obtained within the hard-loop approximation, are shown to have unique forms for a whole class of gauge theories including QED, scalar QED, super QED, pure Yang-Mills, QCD, super Yang-Mills. The universality occurs irrespective of a field content of each theory and of variety of specific interactions. Consequently, the long-wavelength or semiclassical features of plasma systems governed by these theories such as collective excitations are almost identical. An origin of the universality, which holds within the limits of applicability of the hard-loop approach, is discussed.

  3. Dynamic leaching test of personal computer components

    Microsoft Academic Search

    Yadong Li; Jay B. Richardson; Xiaojun Niu; Ollie J. Jackson; Jeremy D. Laster; Aaron K. Walker

    2009-01-01

    A dynamic leaching test (DLT) was developed and used to evaluate the leaching of toxic substances for electronic waste in the environment. The major components in personal computers (PCs) including motherboards, hard disc drives, floppy disc drives, and compact disc drives were tested. The tests lasted for 2 years for motherboards and 1.5 year for the disc drives. The extraction

  4. Complexation in two-component chlortetracycline-melanin solutions

    NASA Astrophysics Data System (ADS)

    Lapina, V. A.; Pershukevich, P. P.; Dontsov, A. E.; Bel'Kov, M. V.

    2008-01-01

    The spectra and kinetics of fluorescence of two-component solutions of the chlortetracycline (CHTC)-DOPA-melanin (melanin or ME) system in water have been investigated. The data obtained have been compared to similar data for solutions of CHTC-melanosome from bull eye (MB), which contains natural melanin, in K-phosphate buffer at pH 7.4. The overall results indicate the occurrence of complexation between molecules of CHTC and ME as they are being excited. The studies of complexation in the solution of CHTC-MB in the buffer are complicated by the formation of a CHTC-buffer complex. The effect of optical radiation in the range 330-750 nm on the CHTC-ME complex shows selectivity: the greatest change in the spectrum occurs when the wavelength of the exciting radiation coincides with the long-wavelength band maximum of the fluorescence excitation spectrum of the CHTC-ME complex in aqueous solution. In this range, CHTC and especially ME show high photochemical stability. The nature of the radiation effect on the studied compounds in the hard UV range (? < 330 nm) differs greatly from that in the range 330-750 nm. It is apparently accompanied by significant photochemical transmutations of all system components. By comparing the characteristics of the CHTC-ME systems with those of the related drug doxycycline (DC-ME), the conclusion has been made that the chlorine atom plays a vital role in formation of the short-wavelength band in the fluorescence spectrum of the CHTC-ME complex.

  5. What Causes The Increasing Submillimeter Spectral Component Of Solar Flares?

    NASA Astrophysics Data System (ADS)

    Silva, Adriana V. R.; Share, G. H.; Murphy, R. J.; Costa, J. E.; Gimenez de Castro, C. G.; Raulin, J. P.; Kaufmann, P.

    2007-05-01

    The flare on November 2nd, 2003, at 17:17 UT, occurred on the very active region 486 located at S14W56. This X8.3 flare was simultaneously detected by RHESSI and the Solar Submillimeter Telescope (SST) at 212 and 405 GHz. The time profile of the submm emission resembles that of the high energy X-rays observed by RHESSI and the microwaves observed by OVSA. Moreover, the centroid position of the submm radiation is seen to originate within the same flaring loops of the ultraviolet and X-rays sources. Nevertheless, the submm spectra are distinct from the usual microwave spectra, showing a flux density increase with frequency. Three possibilities to explain this increasing radio spectra are discussed: (1) bremsstrahlung from thermal electrons, (2) gyrosynchrotron radiation from accelerated electrons, and finally (3) gyrosynchrotron emission from the positrons produced by pion or radioactive decay after nuclear interactions. It is possible to model the emission as thermal, the problem, however, is to explain the good agreement of the submm temporal profile with those of the non-thermal emission seen in microwaves and hard X-rays. If the submm emission is to be explained by gyrosynchrotron from the same population of accelerated electrons that emit hard X-rays, however, a discrepancy of 300 times more electrons between 40 keV and 20 MeV is found between the fit to the high frequency radio spectra and what was observed by RHESSI, even for a 3000 G field. Finally, synchrotron emission from positrons requires 3.3 - 10 × 105 more positrons than what is inferred from X and gamma-ray observations, thus ruling this out as a possible explanation. In summary, all possibilities listed above run into problems when trying to explain the increasing submm spectra, because of the extreme source parameters required. Therefore, the cause of this new component still remains unknown.

  6. Covering Problems with Hard Capacities

    Microsoft Academic Search

    Julia Chuzhoy; Joseph Naor

    2002-01-01

    We consider the classical vertex cover and set cover problems with the addition of hard capacity constraints. This means that a set (vertex) can only cover a limited number of its elements (adjacent edges) and the number of available copies of each set (vertex) is bounded. This is a natural generalization of the classical problems that also captures resource limitations

  7. Hard scattering in gammap interactions

    Microsoft Academic Search

    T. Ahmed; V. Andreev; B. Andrieu; M. Arpagaus; A. Babayev; H. Bärwolff; J. Ban; P. Baranov; E. Barrelet; W. Bartel; U. Bassler; G. A. Beck; H. P. Beck; H.-J. Behrend; A. Belousov; Ch. Berger; H. Bergstein; G. Bernardi; R. Bernet; U. Berthon; G. Bertrand-Coremans; M. Besancon; P. Biddulph; E. Binder; J. C. Bizot; V. Blobel; K. Borras; P. C. Bosetti; V. Boudry; C. Bourdarios; F. Brasse; U. Braun; W. Braunschweig; V. Brisson; D. Bruncko; J. Bürger; F. W. Büsser; A. Buniatian; S. Burke; G. Buschhorn; A. J. Campbell; T. Carli; F. Charles; D. Clarke; A. B. Clegg; M. Colombo; J. A. Coughlan; A. Courau; C. Coutures; G. Cozzika; L. Criegee; J. Cvach; J. B. Dainton; M. Danilov; A. W. E. Dann; W. D. Dau; M. David; E. Deffur; B. Delcourt; L. Delbuono; M. Devel; A. Deroeck; P. Dingus; C. Dollfus; J. D. Dowell; H. B. Dreis; A. Drescher; J. Duboc; D. Düllmann; O. Dünger; H. Duhm; M. Eberle; J. Ebert; T. R. Ebert; G. Eckerlin; V. Efremenko; S. Egli; S. Eichenberger; R. Eichler; F. Eisele; E. Eisenhandler; N. N. Ellis; R. J. Ellison; E. Elsen; M. Erdmann; E. Evrard; L. Favart; A. Fedotov; D. Feeken; R. Felst; J. Feltesse; Y. Feng; I. F. Fensome; J. Ference; F. Ferrarotto; W. Flauger; M. Fleischer; G. Flügge; A. Fomenko; B. Fominykh; M. Forbush; J. Formanek; J. M. Foster; G. Franke; E. Fretwurst; P. Fuhrmann; E. Gabathuler; K. Gamerdinger; J. Garvey; J. Gayler; A. Gellrich; M. Gennis; U. Gensch; H. Genzel; R. Gerhards; D. Gillespie; L. Godfrey; U. Goerlach; L. Goerlich; M. Goldberg; A. M. Goodall; I. Gorelov; P. Goritchev; C. Grab; H. Grässler; T. Greenshaw; H. Greif; G. Grindhammer; C. Gruber; J. Haack; D. Haidt; L. Hajduk; O. Hamon; D. Handschuh; E. M. Hanlon; M. Hapke; J. Harjes; P. Hartz; R. Haydar; W. J. Haynes; J. Heatherington; V. Hedberg; R. Hedgecock; G. Heinzelmann; R. C. W. Henderson; H. Henschel; R. Herma; I. Herynek; W. Hildesheim; P. Hill; C. D. Hilton; J. Hladky; K. C. Hoeger; Ph. Huet; H. Hufnagel; N. Huot; M. Ibbotson; M. A. Jabiol; A. Jacholkowska; C. Jacobson; M. Jaffre; L. Jönsson; K. Johannsen; D. Johnson; L. Johnson; H. Jung; P. I. P. Kalmus; S. Kasarian; R. Kaschowitz; P. Kasselmann; U. Kathage; H. H. Kaufmann; I. R. Kenyon; S. Kermiche; C. Kiesling; M. Klein; C. Kleinwort; G. Knies; T. Köhler; H. Kolanoski; F. Kole; S. D. Kolya; V. Korbel; M. Korn; P. Kostka; S. K. Kotelnikov; M. W. Krasny; H. Krehbiel; D. Krücker; U. Krüger; J. P. Kubenka; H. Küster; M. Kuhlen; T. Kurca; J. Kurzhöfer; B. Kuznik; R. Lander; M. P. J. Landon; R. Langkau; P. Lanius; J. F. Laporte; A. Lebedev; U. Lenhardt; A. Leuschner; C. Leverenz; D. Levin; S. Levonian; Ch. Ley; G. Lindström; P. Loch; H. Lohmander; G. C. Lopez; D. Lüers; N. Magnussen; E. Malinovski; S. Mani; P. Marage; J. Marks; R. Marshall; J. Martens; R. Martin; H.-U. Martyn; J. Martyniak; S. Masson; A. Mavroidis; S. J. Maxfield; S. J. McMahon; A. Mehta; K. Meier; T. Merz; C. A. Meyer; H. Meyer; J. Meyer; S. Mikocki; V. Milone; E. Monnier; F. Moreau; J. Moreels; J. V. Morris; J. M. Morton; K. Müller; P. Murin; S. A. Murray; V. Nagovizin; B. Naroska; Th. Naumann; D. Newton; H. K. Nguyen; F. Niebergall; R. Nisius; G. Nowak; G. W. Noyes; M. Nyberg; H. Oberlack; U. Obrock; J. E. Olsson; S. Orenstein; F. Ould-Saada; C. Pascaud; G. D. Patel; E. Peppel; S. Peters; H. T. Phillips; J. P. Phillips; Ch. Pichler; W. Pilgram; D. Pitzl; R. Prosi; F. Raupach; K. Rauschnabel; P. Reimer; P. Ribarics; V. Riech; J. Riedlberger; M. Rietz; S. M. Robertson; P. Robmann; R. Roosen; A. Rostovtsev; C. Royon; M. Rudowicz; M. Ruffer; S. Rusakov; K. Rybicki; E. Ryseck; J. Sacton; N. Sahlmann; E. Sanchez; D. P. Sankey; M. Savitsky; P. Schacht; P. Schleper; W. von Schlippe; C. Schmidt; D. Schmidt; W. Schmitz; V. Schröder; M. Schulz; A. Schwind; W. Scobel; U. Seehausen; R. Sell; M. Seman; A. Semenov; V. Shekelyan; I. Sheviakov; H. Shooshtari; G. Siegmon; U. Siewert; Y. Sirois; I. O. Skillicorn; P. Smirnov; J. R. Smith; L. Smolik; Y. Soloviev; H. Spitzer; P. Staroba; M. Steenbock; P. Steffen; R. Steinberg; H. Steiner; B. Stella; K. Stephens; J. Strachota; U. Straumann; W. Struczinski; J. P. Sutton; R. E. Taylor; G. Thompson; R. J. Thompson; I. Tichomirov; C. Trenkel; P. Truöl; V. Tchernyshov; J. Turnau; J. Tutas; L. Urban; A. Usik; S. Valkar; A. Valkarova; C. Vallee; P. Vanesch; A. Vartapetian; J. Vasdik; M. Vecko; P. Verrecchia; R. Vick; G. Villet; E. Vogel; K. Wacker; I. W. Walker; A. Walther; G. Weber; D. Wegener; A. Wegner; H. P. Wellisch; S. Willard; M. Winde; G.-G. Winter; M. Th. Wolff; L. A. Womersley; A. E. Wright; N. Wulff; T. P. Yiou; J. Zacek; P. Zavada; C. Zeitnitz; H. Ziaeepour; M. Zimmer; W. Zimmermann; F. Zomer

    1992-01-01

    We report on the investigation of the final state in interactions of quasi-real photons with protons. The data were taken with the H1 detector at the HERA ep collider. Evidence for hard interactions is seen in both single particle spectra and jet formation. The data can best be described by inclusion of resolved photon processess as predicted by QCD.

  8. FATIGUE OF BIOMATERIALS: HARD TISSUES

    PubMed Central

    Arola, D.; Bajaj, D.; Ivancik, J.; Majd, H.; Zhang, D.

    2009-01-01

    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

  9. Radiation Effects on Superconducting Fusion Magnet Components

    Microsoft Academic Search

    Harald W. Weber

    2011-01-01

    Nuclear fusion devices based on the magnetic confinement principle heavily rely on the existence and performance of superconducting magnets and have always significantly contributed to advancing superconductor and magnet technology to their limits. In view of the presently ongoing construction of the tokamak device ITER and the stellerator device Wendelstein 7X and their record breaking parameters concerning size, complexity of

  10. On dynamics of hard elastic scattering of hadrons

    NASA Astrophysics Data System (ADS)

    Kancheli, O. V.

    2015-05-01

    The main contribution to hard elastic scattering at high energies comes from components of wave functions of colliding hadrons that contain minimal number of partons. We discuss the details of such a mechanism in the regge and parton approaches and estimate the probability that colliding hadrons are in bare states containing only valent partons. The behavior of cross sections in this regime at various energies can give nontrivial information on high energy dynamics.

  11. Implementation of Hard Real-Time Embedded Control Systems

    Microsoft Academic Search

    Matjaz Colnaric; Domen Verber; Roman Gumzej; Wolfgang A. Halang

    1998-01-01

    Although the domain of hard real-time systems has been thoroughly elaborated in the academic sphere, embedded computer control\\u000a systems — being an important component in mechatronic designs — are seldom dealt with consistently. Often, off-the-shelf computer\\u000a systems are used, with no guarantee that they will be able to meet the requirements specified. In this paper, a design for\\u000a embedded control

  12. Development of a fast radiation detector based on barium fluoride scintillation crystal.

    PubMed

    Han, Hetong; Zhang, Zichuan; Weng, Xiufeng; Liu, Junhong; Guan, Xingyin; Zhang, Kan; Li, Gang

    2013-07-01

    Barium fluoride (BaF2) 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. BaF2 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 BaF2 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 BaF2 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. PMID:23902059

  13. 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.

  14. Metals distribution and investigation of L'vov platform surface using principal component analysis, multi-way principal component analysis, micro synchrotron radiation X-ray fluorescence spectrometry and scanning electron microscopy after the determination of Al in a milk slurry sample

    NASA Astrophysics Data System (ADS)

    Pereira-Filho, E. R.; Pérez, C. A.; Poppi, R. J.; Arruda, M. A. Z.

    2002-08-01

    This work describes the use of different strategies/techniques, such as scanning electron microscopy (SEM), multivariate analysis (principal component analysis (PCA) and multi-way PCA) and micro synchrotron radiation X-ray fluorescence (?SRXRF), in order to extract information about platform morphology, metals distribution on its surface, and the performance of conventional and permanent modifiers after slurry analyses using electrothermal atomic absorption spectrometry (ET AAS). With multivariate analysis it was possible to select Zr (500 ?g for each 50 heating cycles) as a permanent chemical modifier for the determination of Al in milk powder slurry samples. Employing multi-way PCA and SEM, it was possible to note the differences in morphology between platforms permanently treated with Zr and those conventionally treated with Mg(NO 3) 2. The use of PCA and SEM also allowed finding similarities between new platforms, and those with and without Zr treatment. Using the ?SRXRF it was possible to establish metals distribution on the L'vov platform and compare the performance of conventional [Mg(NO 3) 2] and permanent (Zr) modifiers.

  15. 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.

  16. Computational Modeling Develops Ultra-Hard Steel

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Glenn Research Center's Mechanical Components Branch developed a spiral bevel or face gear test rig for testing thermal behavior, surface fatigue, strain, vibration, and noise; a full-scale, 500-horsepower helicopter main-rotor transmission testing stand; a gear rig that allows fundamental studies of the dynamic behavior of gear systems and gear noise; and a high-speed helical gear test for analyzing thermal behavior for rotorcraft. The test rig provides accelerated fatigue life testing for standard spur gears at speeds of up to 10,000 rotations per minute. The test rig enables engineers to investigate the effects of materials, heat treat, shot peen, lubricants, and other factors on the gear's performance. QuesTek Innovations LLC, based in Evanston, Illinois, recently developed a carburized, martensitic gear steel with an ultra-hard case using its computational design methodology, but needed to verify surface fatigue, lifecycle performance, and overall reliability. The Battelle Memorial Institute introduced the company to researchers at Glenn's Mechanical Components Branch and facilitated a partnership allowing researchers at the NASA Center to conduct spur gear fatigue testing for the company. Testing revealed that QuesTek's gear steel outperforms the current state-of-the-art alloys used for aviation gears in contact fatigue by almost 300 percent. With the confidence and credibility provided by the NASA testing, QuesTek is commercializing two new steel alloys. Uses for this new class of steel are limitless in areas that demand exceptional strength for high throughput applications.

  17. 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 ...

  18. Hard Photodisintegration of 3He

    NASA Astrophysics Data System (ADS)

    Granados, Carlos

    2011-02-01

    Large angle photodisintegration of two nucleons from the 3He nucleus is studied within the framework of the hard rescattering model (HRM). In the HRM the incoming photon is absorbed by one nucleon's valence quark that then undergoes a hard rescattering reaction with a valence quark from the second nucleon producing two nucleons emerging at large transverse momentum . Parameter free cross sections for pp and pn break up channels are calculated through the input of experimental cross sections on pp and pn elastic scattering. The calculated cross section for pp breakup and its predicted energy dependency are in good agreement with recent experimental data. Predictions on spectator momentum distributions and helicity transfer are also presented.

  19. Laser beam brazing of car body and aircraft components

    SciTech Connect

    Haferkamp, H.; Kreutzburg, K.

    1994-12-31

    At present, when brazing car body components for the automotive industry, manual flame brazing is mostly used. The advantage of brazing as compared to welding, is the lower hardness of the braze metal, making postmachining easier. But manual flame brazing also shows several main disadvantages, such as pores within the seam and a high thermal influence on the workpiece. Therefore, investigations on laser beam brazing concerning the reduction of the technological and economical disadvantages of the flame brazing process were carried out. Laser beam brazing of aluminum alloys is also a main topic of this presentation. The fundamental research in brazing mild steel was done on lap joints. The investigations about brazing mild steel and aluminum alloys have demonstrated that it is possible to braze these metals using laser beam radiation. Laser beam brazing of 3-dimensional mild steel components requires a special program for the brazing sequence, and new specifications in design and fabrication. But comparing seams made by laser beam brazing to manual flame brazing show that there are advantages to using the automated laser process. Laser beam brazing of aluminum alloys makes it possible to join metals with poor brazeability, although brazing conditions lead to a slight melting of the gap sides.

  20. 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...

  1. Hard x-ray detectors for OMEGA and NIF

    SciTech Connect

    Stoeckl, C.; Glebov, V. Yu.; Meyerhofer, D. D.; Seka, W.; Yaakobi, B.; Town, R. P. J.; Zuegel, J. D.

    2001-01-01

    Laser--plasma instabilities that produce an unacceptably high level of hot electrons are potentially dangerous for both direct-drive and indirect-drive inertial confinement laser fusion. The hot electrons preheat the fuel and prevent compression of the capsule to the requisite conditions for ignition. Fast electron generation and preheat can be inferred from the hard x-ray radiation generated by the interaction of the hot electrons with the target. On the University of Rochesters OMEGA laser system, time-resolved hard x-ray detectors have been operating in an energy range from 10 to 500 keV. In this article we will present initial results for the yield and spectrum of the hard x-ray radiation. The concept used on OMEGA can be easily extended to infer the amount of laser energy coupled to suprathermal electrons and to the target for both direct- and indirect-drive implosions on the upcoming National Ignition Facility, as well as to measure the conversion efficiency in high-x-ray-yield experiments.

  2. Radiation Climatology of the Greenland Ice Sheet Derived from Greenland Climate Network Data

    NASA Technical Reports Server (NTRS)

    Steffen, Konrad; Box, Jason

    2003-01-01

    The magnitude of shortwave and longwave dative fluxes are critical to surface energy balance variations over the Greenland ice sheet, affecting many aspects of its climate, including melt rates, the nature of low-level temperature inversions, the katabatic wind regime and buoyant stability of the atmosphere. Nevertheless, reliable measurements of the radiative fluxes over the ice sheet are few in number, and have been of limited duration and areal distribution (e.g. Ambach, 1960; 1963, Konzelmann et al., 1994, Harding et al., 1995, Van den Broeke, 1996). Hourly GC-Net radiation flux measurements spanning 1995-2001 period have been used to produce a monthly dataset of surface radiation balance components. The measurements are distributed widely across Greenland and incorporate multiple sensors

  3. Radiation Protection Aspects of the Linac Coherent Light Source Front End Enclosure

    SciTech Connect

    Vollaire, J.; Fasso, A.; Liu, J.C.; Mao, X.S.; Prinz, A.; Rokni, S.H.; Leitner, M.Santana; /SLAC

    2010-08-26

    The Front End Enclosure (FEE) of the Linac Coherent Light Source (LCLS) is a shielding housing located between the electron dump area and the first experimental hutch. The upstream part of the FEE hosts the commissioning diagnostics for the FEL beam. In the downstream part of the FEE, two sets of grazing incidence mirror and several collimators are used to direct the beam to one of the experimental stations and reduce the bremsstrahlung background and the hard component of the spontaneous radiation spectrum. This paper addresses the beam loss assumptions and radiation sources entering the FEE used for the design of the FEE shielding using the Monte-Carlo code FLUKA. The beam containment system prevents abnormal levels of radiations inside the FEE and ensures that the beam remains in its intended path is also described.

  4. Radiation hardening of a high voltage IC technology (BCDMOS)

    SciTech Connect

    Desko, J.C. Jr.; Darwish, M.N.; Dolly, M.C.; Goodwin, C.A. (AT and T Bell Labs., Reading, PA (USA)); Dawes, W.R. Jr. (Sandia National Labs., Albuquerque, NM (USA)); Titus, J.L. (Naval Weapons Support Center, Crane, IN (USA))

    1990-01-01

    PIC's (Power Integrated Circuits) are becoming increasingly important because they allow integration of high-voltage and high-current power transistors, precision linear control circuitry, and low-voltage logic gates on the same monolithic chip. Integration of power and control functions provide benefits in reduced weight and size, enhanced reliability, and lower costs over conventional designs using these same components packaged separately. However, commercial PIC technologies, including AT T's commercial BCDMOS technology, are susceptible to failure in radiation environments. The relative lack of radiation hardness of the AT T BCDMOS technology was previously reported at this conference. Radiation hardening of PIC technologies is significantly more difficult than for other IC technologies, primarily because of the integration of many different types of devices into the technology. To facilitate integration, different devices share processing sequences. Thus, no one device can be optimized independently of the remaining devices. Since each device has its own distinct radiation response, this adds another set of constraints on the optimization of the overall technology from the point of view of device performance and radiation response. The high-voltage requirements further complicates efforts to harden a PIC technology. Modifying one device to optimize one aspect of its performance can severely impact all the other devices in the technology. 4 refs., 5 figs.

  5. 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

  6. PROTEIN COMPOSITION AND GRAIN HARDNESS IN SORGHUM

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Grain hardness is an important quality trait in sorghum. Grain hardness has been linked to milling and food quality as well as resistance to insects and mold. Despite the importance of grain hardness in sorghum, its biochemical basis is still not well understood. In sorghum, the grain is composed...

  7. 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

  8. Surface Integrity Generated by Precision Hard Turning

    Microsoft Academic Search

    Y. Matsumoto; F. Hashimoto; G. Lahoti

    1999-01-01

    Rolling contact fatigue tests were conducted to find the effect of precision hard turning. The tests showed that hard turning provides as good a fatigue performance as grinding. Hard turning produces compressive residual stresses in a deep subsurface, which contribute to a long fatigue life. The effect of cutting parameters on residual stress was investigated in order to find why

  9. Communication: Radial distribution functions in a two-dimensional binary colloidal hard sphere system

    NASA Astrophysics Data System (ADS)

    Thorneywork, Alice L.; Roth, Roland; Aarts, Dirk G. A. L.; Dullens, Roel P. A.

    2014-04-01

    Two-dimensional hard disks are a fundamentally important many-body model system in classical statistical mechanics. Despite their significance, a comprehensive experimental data set for two-dimensional single component and binary hard disks is lacking. Here, we present a direct comparison between the full set of radial distribution functions and the contact values of a two-dimensional binary colloidal hard sphere model system and those calculated using fundamental measure theory. We find excellent quantitative agreement between our experimental data and theoretical predictions for both single component and binary hard disk systems. Our results provide a unique and fully quantitative mapping between experiments and theory, which is crucial in establishing the fundamental link between structure and dynamics in simple liquids and glass forming systems.

  10. Communication: radial distribution functions in a two-dimensional binary colloidal hard sphere system.

    PubMed

    Thorneywork, Alice L; Roth, Roland; Aarts, Dirk G A L; Dullens, Roel P A

    2014-04-28

    Two-dimensional hard disks are a fundamentally important many-body model system in classical statistical mechanics. Despite their significance, a comprehensive experimental data set for two-dimensional single component and binary hard disks is lacking. Here, we present a direct comparison between the full set of radial distribution functions and the contact values of a two-dimensional binary colloidal hard sphere model system and those calculated using fundamental measure theory. We find excellent quantitative agreement between our experimental data and theoretical predictions for both single component and binary hard disk systems. Our results provide a unique and fully quantitative mapping between experiments and theory, which is crucial in establishing the fundamental link between structure and dynamics in simple liquids and glass forming systems. PMID:24784245

  11. 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

  12. Hard body amphiphiles at a hard wall JOSEPH M. BRADER1y

    E-print Network

    Ott, Albrecht

    Hard body amphiphiles at a hard wall JOSEPH M. BRADER1y , CHRISTIAN VON FERBER2 and MATTHIAS 2003) We investigate the structure of amphiphilic molecules exposed to a substrate that is modelled by a hard wall. Our simple model amphiphiles consist of a hard sphere head group to which a vanishingly thin

  13. Processing and Scheduling Components in an Innovative Network Processor Architecture

    E-print Network

    Vlachos, Kyriakos G.

    Processing and Scheduling Components in an Innovative Network Processor Architecture K. Vlachos1 processing in high speed network interfaces and at the tight coupling of low and high level protocols. The proposed design uses programmable hard-wired components with line rate throughput and is capable

  14. Nanostructural Evolution of Hard Turning Layers in Carburized Steel

    NASA Astrophysics Data System (ADS)

    Bedekar, Vikram

    The mechanisms of failure for components subjected to contact fatigue are sensitive to the structure and properties of the material surface. Although, the bulk material properties are determined by the steel making, forming and the heat treatment; the near surface material properties are altered during final material removal processes such as hard turning or grinding. Therefore, the ability to optimize, modulate and predict the near surface properties during final metal removal operations would be extremely useful in the enhancement of service life of a component. Hard machining is known to induce severely deformed layers causing dramatic microstructural transformations. These transformations occur via grain refinement or thermal phenomena depending upon cutting conditions. The aim of this work is to engineer the near surface nanoscale structure and properties during hard turning by altering strain, strain rate, temperature and incoming microstructure. The near surface material transformations due to hard turning were studied on carburized SAE 8620 bearing steel. Variations in parent material microstructures were introduced by altering the retained austenite content. The strain, strain rate and temperature achieved during final metal cutting were altered by varying insert geometry, insert wear and cutting speed. The subsurface evolution was quantified by a series of advanced characterization techniques such as transmission electron microscopy (TEM), glancing angle X-ray diffraction (GAXRD), X-ray stress evaluation and nanoindentation which were coupled with numerical modeling. Results showed that the grain size of the nanocrystalline near surface microstructure can be effectively controlled by altering the insert geometry, insert wear, cutting speed and the incoming microstructure. It was also evident that the near surface retained austenite decreased at lower cutting speed indicating transformation due to plastic deformation, while it increased at higher cutting speed indicated thermal transformation. Nanoindentation tests showed that the substructures produced by plastic deformation follow the Hall-Petch relationship while the structures produced by thermal transformation did not. This indicated a change in the hardness driver from dislocation hardening to phase transformation, both of which have a significant impact on fatigue life. Using hardness based flow stress numerical model, these relationships between the processing conditions and structural parameters were further explored. Results indicated that the hard turning process design space can be partitioned into three regions based on thermal phase transformations, plastic grain refinement, and a third regime where both mechanisms are active. It was found that the Zener-Holloman parameter can not only be used to predict post-turning grain size but also to partition the process space into regions of dominant microstructural mechanisms.

  15. Microstructures and mechanical properties evaluation of hard chromized austenitic Fe–Mn–Al alloys

    Microsoft Academic Search

    Jyh-Wei Lee

    2005-01-01

    Engineering components with hard coatings usually exhibit improved service behavior and increased lifetime. Hard chromizing technique is employed to deposit chromium nitride and carbides layer on the surface of an austenitic Fe–30.6Mn–6.8Al–0.9C alloy. The (Cr, Fe)2N1?x and (Cr, Fe)23C6 phases are found on the chromized surface, while the internal part of chromized layer is (Cr, Fe)7C3 phase. The thickness of

  16. Space Radiation Effects and Hardness Assurance for Linear Integrated Circuits

    NASA Technical Reports Server (NTRS)

    Johnston, A. H.

    2000-01-01

    New effects that complicate the application of linear devices in space are discussed, including enhanced damage at low dose rate and proton damage, which cause permanent degradation. Transients produced by protons and heavy ions are also discussed.

  17. Investigation of avalanche photodiodes radiation hardness for baryonic matter studies

    E-print Network

    Kushpil, V; Ladygin, V P; Kugler, A; Kushpil, S; Svoboda, O; Tlustý, P

    2015-01-01

    Modern avalanche photodiodes (APDs) with high gain are good device candidates for light readout from detectors applied in relativistic heavy ion collisions experiments. The results of the investigations of the APDs properties from Zecotek, Ketek and Hamamatsu manufacturers after irradiation using secondary neutrons from cyclotron facility U120M at NPI of ASCR in \\v{R}e\\v{z} are presented. The results of the investigations can be used for the design of the detectors for the experiments at NICA and FAIR.

  18. A Bayesian Treatment of Risk for Radiation Hardness Assurance

    NASA Technical Reports Server (NTRS)

    Ladbury, R.; Gorelick, J. L.; Xapsos, M. A.; O'Connor, T.; Demosthenes, Sandor

    2005-01-01

    They construct a Bayesian risk metric with a method that allows for efficient and systematic use of all relevant information and provides rational basis for RHA decisions in terms of costs and mission requirements

  19. Radiation-hard semiconductor detectors for SuperLHC

    Microsoft Academic Search

    M. Bruzzi; J. Adey; A. Al-Ajili; P. Alexandrov; G. Alfieri; P. P. Allport; A. Andreazza; M. Artuso; S. Assouak; B. S. Avset; L. Barabash; E. Baranova; A. Barcz; A. Basile; R. Bates; N. Belova; S. F. Biagi; G. M. Bilei; D. Bisello; A. Blue; A. Blumenau; V. Boisvert; G. Bolla; G. Bondarenko; E. Borchi; L. Borrello; D. Bortoletto; M. Boscardin; L. Bosisio; T. J. V. Bowcock; T. J. Brodbeck; J. Broz; A. Brukhanov; A. Brzozowski; M. Buda; P. Buhmann; C. Buttar; F. Campabadal; D. Campbell; A. Candelori; G. Casse; A. Cavallini; A. Chilingarov; D. Chren; V. Cindro; M. Citterio; P. Collins; R. Coluccia; D. Contarato; J. Coutinho; D. Creanza; W. Cunningham; V. Cvetkov; G.-F. Dalla Betta; G. Davies; I. Dawson; W. de Boer; M. De Palma; R. Demina; P. Dervan; A. Dierlamm; S. Dittongo; L. Dobrzanski; Z. Dolezal; A. Dolgolenko; T. Eberlein; V. Eremin; C. Fall; F. Fasolo; T. Ferbel; F. Fizzotti; C. Fleta; E. Focardi; E. Forton; S. Franchenko; E. Fretwurst; F. Gamaz; C. Garcia; J. E. Garcia-Navarro; E. Gaubas; M.-H. Genest; K. A. Gill; K. Giolo; M. Glaser; C. Goessling; V. Golovine; S. González Sevilla; I. Gorelov; J. Goss; A. Gouldwell; G. Grégoire; P. Gregori; E. Grigoriev; C. Grigson; A. Grillo; A. Groza; J. Guskov; L. Haddad; J. Härkönen; R. Harding; F. Hauler; S. Hayama; M. Hoeferkamp; F. Hönniger; T. Horazdovsky; R. Horisberger; M. Horn; A. Houdayer; B. Hourahine; A. Hruban; G. Hughes; I. Ilyashenko; K. Irmscher; A. Ivanov; K. Jarasiunas; T. Jin; B. K. Jones; R. Jones; C. Joram; L. Jungermann; E. Kalinina; P. Kaminski; A. Karpenko; A. Karpov; V. Kazlauskiene; V. Kazukauskas; V. Khivrich; V. Khomenkov; J. Kierstead; J. Klaiber-Lodewigs; M. Kleverman; R. Klingenberg; P. Kodys; Z. Kohout; S. Korjenevski; A. Kowalik; R. Kozlowski; M. Kozodaev; G. Kramberger; O. Krasel; A. Kuznetsov; S. Kwan; S. Lagomarsino; T. Lari; K. Lassila-Perini; V. Lastovetsky; G. Latino; S. Latushkin; S. Lazanu; I. Lazanu; C. Lebel; K. Leinonen; C. Leroy; Z. Li; G. Lindström; L. Lindstrom; V. Linhart; A. Litovchenko; P. Litovchenko; V. Litvinov; A. Lo Giudice; M. Lozano; Z. Luczynski; P. Luukka; A. Macchiolo; A. Mainwood; L. F. Makarenko; I. Mandi?; C. Manfredotti; S. Marti i Garcia; S. Marunko; K. Mathieson; A. Mozzanti; J. Melone; D. Menichelli; C. Meroni; A. Messineo; S. Miglio; M. Mikuz; J. Miyamoto; M. Moll; E. Monakhov; F. Moscatelli; L. Murin; F. Nava; D. Naoumov; E. Nossarzewska-Orlowska; S. Nummela; J. Nysten; P. Olivero; V. Oshea; T. Palviainen; C. Paolini; C. Parkes; D. Passeri; U. Pein; G. Pellegrini; L. Perera; M. Petasecca; B. Piatkowski; C. Piemonte; G. U. Pignatel; N. Pinho; I. Pintilie; L. Pintilie; L. Polivtsev; P. Polozov; A. I. Popa; J. Popule; S. Pospisil; G. Pucker; V. Radicci; J. M. Rafí; F. Ragusa; M. Rahman; R. Rando; R. Roeder; T. Rohe; S. Ronchin; C. Rott; P. Roy; A. Roy; A. Ruzin; A. Ryazanov; H. F. W. Sadrozinski; S. Sakalauskas; M. Scaringella; L. Schiavulli; S. Schnetzer; B. Schumm; S. Sciortino; A. Scorzoni; G. Segneri; S. Seidel; A. Seiden; G. Sellberg; P. Sellin; D. Sentenac; I. Shipsey; P. Sicho; T. Sloan; M. Solar; S. Son; B. Sopko; N. Spencer; J. Stahl; I. Stavitski; D. Stolze; R. Stone; J. Storasta; N. Strokan; W. Strupinski; M. Sudzius; B. Surma; J. Suuronen; A. Suvorov; B. G. Svensson; P. Tipton; M. Tomasek; C. Troncon; A. Tsvetkov; E. Tuominen; E. Tuovinen; T. Tuuva; M. Tylchin; H. Uebersee; J. Uher; M. Ullán; J. V. Vaitkus; P. Vanni; J. Velthuis; G. Verzellesi; E. Verbitskaya; V. Vrba; G. Wagner; I. Wilhelm; S. Worm; V. Wright; R. Wunstorf; P. Zabierowski; A. Zaluzhny; M. Zavrtanik; M. Zen; V. Zhukov; N. Zorzi

    2005-01-01

    An option of increasing the luminosity of the Large Hadron Collider (LHC) at CERN to 1035cm?2s?1 has been envisaged to extend the physics reach of the machine. An efficient tracking down to a few centimetres from the interaction point will be required to exploit the physics potential of the upgraded LHC. As a consequence, the semiconductor detectors close to the

  20. Zone Plates for Hard X-Ray FEL Radiation

    SciTech Connect

    Nilsson, D.; Holmberg, A.; Vogt, U. [Biomedical and X-Ray Physics, Royal Institute of Technology, KTH-Albanova, SE-106 91 Stockholm (Sweden); Sinn, H. [European XFEL - Notkestrasse 85, D-22607 Hamburg (Germany)

    2011-09-09

    We investigated theoretically the use of zone plates for the focusing of the European X-ray Free Electron Laser (XFEL). In a finite-element simulation the heat load on zone plates placed in the high intensity x-ray beam was simulated for four different zone plate materials: gold, iridium, tungsten, and CVD diamond. The main result of the calculations is that all zone plates remain below the melting temperature throughout a full XFEL pulse train of 3000 pulses. However, if the zone plate is placed in the direct beam it will experience large and rapid temperature fluctuations on the order of 300 K. The situation is relaxed if the optic is placed behind a monochromator and the fluctuations are reduced to around 20 K. Besides heat load, the maximization of the total efficiency of the complete optical system is an important issue. We calculated the efficiency of different zone plates and monochromator systems and found that the final beam size of the XFEL in combination with its monochromaticity will be important parameters.

  1. Hard X-ray emission of Sco X-1

    NASA Astrophysics Data System (ADS)

    Revnivtsev, Mikhail G.; Tsygankov, Sergey S.; Churazov, Eugene M.; Krivonos, Roman A.

    2014-12-01

    We study hard X-ray emission of the brightest accreting neutron star Sco X-1 with INTEGRAL observatory. Up to now INTEGRAL have collected ˜4 Ms of deadtime corrected exposure on this source. We show that hard X-ray tail in time average spectrum of Sco X-1 has a power-law shape without cutoff up to energies ˜200-300 keV. An absence of the high energy cutoff does not agree with the predictions of a model, in which the tail is formed as a result of Comptonization of soft seed photons on bulk motion of matter near the compact object. The amplitude of the tail varies with time with factor more than 10 with the faintest tail at the top of the so-called flaring branch of its colour-colour diagram. We show that the minimal amplitude of the power-law tail is recorded when the component, corresponding to the innermost part of optically thick accretion disc, disappears from the emission spectrum. Therefore, we show that the presence of the hard X-ray tail may be related with the existence of the inner part of the optically thick disc. We estimate cooling time for these energetic electrons and show that they cannot be thermal. We propose that the hard X-ray tail emission originates as a Compton upscattering of soft seed photons on electrons, which might have initial non-thermal distribution.

  2. Influence of water layer thickness on hard tissue ablation with pulsed CO2 laser

    NASA Astrophysics Data System (ADS)

    Zhang, Xianzeng; Zhan, Zhenlin; Liu, Haishan; Zhao, Haibin; Xie, Shusen; Ye, Qing

    2012-03-01

    The theory of hard tissue ablation reported for IR lasers is based on a process of thermomechanical interaction, which is explained by the absorption of the radiation in the water component of the tissue. The microexplosion of the water is the cause of tissue fragments being blasted from hard tissue. The aim of this study is to evaluate the influence of the interdependence of water layer thickness and incident radiant exposure on ablation performance. A total of 282 specimens of bovine shank bone were irradiated with a pulse CO2 laser. Irradiation was carried out in groups: without a water layer and with a static water layer of thickness ranging from 0.2 to 1.2 mm. Each group was subdivided into five subgroups for different radiant exposures ranging from 18 to 84 J/cm2, respectively. The incision geometry, surface morphology, and microstructure of the cut walls as well as thermal injury were examined as a function of the water layer thickness at different radiant exposures. Our results demonstrate that the additional water layer is actually a mediator of laser-tissue interaction. There exists a critical thickness of water layer for a given radiant exposure, at which the additional water layer plays multiple roles, not only acting as a cleaner to produce a clean cut but also as a coolant to prevent bone heating and reduce thermal injury, but also helping to improve the regularity of the cut shape, smooth the cut surface, and enhance ablation rate and efficiency. The results suggest that desired ablation results depend on optimal selection of both water layer thickness and radiant exposure.

  3. Water hydraulic polymer components under irradiation

    Microsoft Academic Search

    Teresa Hernández; Eric R. Hodgson

    2007-01-01

    Polymers will be used as different sealing and glide components in the hydraulic remote handling systems for lifting and moving activities in ITER. The degradation of the polymer materials does not depend only on the radiation dose but also on the irradiation environment, and for remote handling hydraulic applications the components have to work in high humidity or water. In

  4. The Hard Problem of Cooperation

    PubMed Central

    Eriksson, Kimmo; Strimling, Pontus

    2012-01-01

    Based on individual variation in cooperative inclinations, we define the “hard problem of cooperation” as that of achieving high levels of cooperation in a group of non-cooperative types. Can the hard problem be solved by institutions with monitoring and sanctions? In a laboratory experiment we find that the answer is affirmative if the institution is imposed on the group but negative if development of the institution is left to the group to vote on. In the experiment, participants were divided into groups of either cooperative types or non-cooperative types depending on their behavior in a public goods game. In these homogeneous groups they repeatedly played a public goods game regulated by an institution that incorporated several of the key properties identified by Ostrom: operational rules, monitoring, rewards, punishments, and (in one condition) change of rules. When change of rules was not possible and punishments were set to be high, groups of both types generally abided by operational rules demanding high contributions to the common good, and thereby achieved high levels of payoffs. Under less severe rules, both types of groups did worse but non-cooperative types did worst. Thus, non-cooperative groups profited the most from being governed by an institution demanding high contributions and employing high punishments. Nevertheless, in a condition where change of rules through voting was made possible, development of the institution in this direction was more often voted down in groups of non-cooperative types. We discuss the relevance of the hard problem and fit our results into a bigger picture of institutional and individual determinants of cooperative behavior. PMID:22792282

  5. Sampling hard to reach populations.

    PubMed

    Faugier, J; Sargeant, M

    1997-10-01

    Studies on 'hidden populations', such as homeless people, prostitutes and drug addicts, raise a number of specific methodological questions usually absent from research involving known populations and less sensitive subjects. This paper examines the advantages and limitations of nonrandom methods of data collection such as snowball sampling. It reviews the currently available literature on sampling hard to reach populations and highlights the dearth of material currently available on this subject. The paper also assesses the potential for using these methods in nursing research. The sampling methodology used by Faugier (1996) in her study of prostitutes, HIV and drugs is used as a current example within this context. PMID:9354993

  6. Principal component analysis for classifying passive sonar signals

    Microsoft Academic Search

    William Soares-filho; José Manoel De Seixas; Luiz Pereira Calôba

    2001-01-01

    Principal component analysis in the frequency domain is used for neural identification of the radiated noise from ships. For comparison, components are extracted from three different approaches: linear (PCA) and nonlinear (NLPCA) principal component analysis, and neural discriminating analysis (NDA). The classifier using NDA achieves a classification efficiency of about 93% using only 3 components, while the classifiers using PCA

  7. Lightweight and Generative Components II: Binarylevel Components

    E-print Network

    Kamin, Sam

    Lightweight and Generative Components II: Binary­level Components Sam Kamin ? , Miranda Callahan, Lars Clausen Computer Science Department University of Illinois at Urbana­Champaign Urbana, IL 61801 fs­kamin,lrclause,mcallahag@uiuc.edu Abstract. Most software component technologies fail to account for lightweight components (those for which

  8. Radiation Protection Studies for LCLS Tune Up Dump

    SciTech Connect

    Santana-Leitner, M.; Fass, A.; Mao, S.; Nuhn, H.D.; /SLAC; Roesler, S.; /CERN; Rokni, S.; Vollaire, J.; /SLAC

    2010-04-29

    The Linac Coherent Light Source (LCLS) at the Stanford Linear Accelerator Center is a pioneer fourth generation hard x-ray free electron laser that shall start to deliver laser pulses in 2009. Among other components of LCLS that present radiation protection concerns, the tune up dump (tdund) is of special interest because it also constitutes an issue for machine protection, as it is placed close to radiation sensitive components, like electronic devices and permanent magnets in the undulators. This paper first introduces the stopper of tdund looking at the heat load, and then it describes the shielding around the dump necessary to maintain the prompt and residual dose within design values. Next, preliminary comparisons of the magnetization loss in a dedicated on-site magnet irradiation experiment with FLUKA simulations serve to characterize the magnetic response to radiation of magnets like those of LCLS. The previous knowledge, together with the limit for the allowed demagnetization, are used to estimate the lifetime of the undulator. Further simulations provide guidelines on which lifetime can be expected for an electronic device placed at a given distance of tdund.

  9. Hard and Soft Safety Verifications

    NASA Technical Reports Server (NTRS)

    Wetherholt, Jon; Anderson, Brenda

    2012-01-01

    The purpose of this paper is to examine the differences between and the effects of hard and soft safety verifications. Initially, the terminology should be defined and clarified. A hard safety verification is datum which demonstrates how a safety control is enacted. An example of this is relief valve testing. A soft safety verification is something which is usually described as nice to have but it is not necessary to prove safe operation. An example of a soft verification is the loss of the Solid Rocket Booster (SRB) casings from Shuttle flight, STS-4. When the main parachutes failed, the casings impacted the water and sank. In the nose cap of the SRBs, video cameras recorded the release of the parachutes to determine safe operation and to provide information for potential anomaly resolution. Generally, examination of the casings and nozzles contributed to understanding of the newly developed boosters and their operation. Safety verification of SRB operation was demonstrated by examination for erosion or wear of the casings and nozzle. Loss of the SRBs and associated data did not delay the launch of the next Shuttle flight.

  10. Development of CVD diamond radiation detectors

    Microsoft Academic Search

    W Adam; C Bauer; E Berdermann; F Bogani; E Borchi; Mara Bruzzi; C Colledani; J Conway; W Dabrowski; P A Delpierre; A Deneuville; W Dulinski; B van Eijk; A Fallou; D Fisch; F Foulon; M Friedl; K K Gan; E Gheeraert; E A Grigoriev; G D Hallewell; R Hall-Wilton; S Han; F G Hartjes; Josef Hrubec; D Husson; H Kagan; D R Kania; J Kaplon; R Kass; K T Knöpfle; Manfred Krammer; P F Manfredi; D Meier; M Mishina; F Le Normand; L S Pan; H Pernegger; Manfred Pernicka; S Pirollo; V Re; J L Riester; S Roe; D G Roff; A Rudge; S R Schnetzer; S Sciortino; V Speziali; H Stelzer; R Stone; R J Tapper; R J Tesarek; G B Thomson; M L Trawick; W Trischuk; R Turchetta; A M Walsh; R Wedenig; Peter Weilhammer; H J Ziock; M M Zoeller

    1998-01-01

    Diamond is a nearly ideal material for detecting ionizing radiation. Its outstanding radiation hardness, fast charge collection and low leakage current allow a diamond detector to be used in high ra diation, high temperature and in aggressive chemical media. We have constructed charged particle detectors using high quality CVD diamond. Characterization of the diamond samples and various detect ors are

  11. Prevocational Training for the Hard-to-Employ--A Systems Approach. Perspectives on Training the Disadvantaged--The Hard-to-Employ. Personnel Services Review Series 2.

    ERIC Educational Resources Information Center

    Harrison, Don K.

    The author, as former administrative head of Detroit Northern Systems Company, describes that company's successful approach to the training of the hard-core unemployed. The systems approach emphasizes the achievement of goals and sub-goals through an interplay of program components which include training lines of 'tool stations,' back-up classes…

  12. Astronaut radiation exposure in low-earth orbit. Part 1. Galactic cosmic radiation

    Microsoft Academic Search

    Letaw

    1988-01-01

    In recent years, there has been increasing concern about the radiation doses that will be suffered by astronauts on present-day and future space missions. In order to characterize radiation exposure risks on space missions one requires models of space-radiation environments, codes for transporting the components of ionizing radiation, and procedures for assessing radiation risks of a given exposure. To verify

  13. System for inspecting large size structural components

    DOEpatents

    Birks, Albert S. (Columbus, OH); Skorpik, James R. (Kennewick, WA)

    1990-01-01

    The present invention relates to a system for inspecting large scale structural components such as concrete walls or the like. The system includes a mobile gamma radiation source and a mobile gamma radiation detector. The source and detector are constructed and arranged for simultaneous movement along parallel paths in alignment with one another on opposite sides of a structural component being inspected. A control system provides signals which coordinate the movements of the source and detector and receives and records the radiation level data developed by the detector as a function of source and detector positions. The radiation level data is then analyzed to identify areas containing defects corresponding to unexpected variations in the radiation levels detected.

  14. Flexible radiator system

    NASA Technical Reports Server (NTRS)

    Oren, J. A.

    1982-01-01

    The soft tube radiator subsystem is described including applicable system requirements, the design and limitations of the subsystem components, and the panel manufacturing method. The soft tube radiator subsystem is applicable to payloads requiring 1 to 12 kW of heat rejection for orbital lifetimes per mission of 30 days or less. The flexible radiator stowage volume required is about 60% and the system weight is about 40% of an equivalent heat rejection rigid panel. The cost should also be considerably less. The flexible radiator is particularly suited to shuttle orbiter sortie payloads and also whose mission lengths do not exceed the 30 day design life.

  15. Non-thermal Hard X-Ray Emission from Coma and Several Abell Clusters

    SciTech Connect

    Correa, C

    2004-02-05

    We report results of hard X-Ray observations of the clusters Coma, Abell 496, Abell754, Abell 1060, Abell 1367, Abell2256 and Abell3558 using RXTE data from the NASA HEASARC public archive. Specifically we searched for clusters with hard x-ray emission that can be fitted by a power law because this would indicate that the cluster is a source of non-thermal emission. We are assuming the emission mechanism proposed by Vahk Petrosian where the inter cluster space contains clouds of relativistic electrons that by themselves create a magnetic field and emit radio synchrotron radiation. These relativistic electrons Inverse-Compton scatter Microwave Background photons up to hard x-ray energies. The clusters that were found to be sources of non-thermal hard x-rays are Coma, Abell496, Abell754 and Abell 1060.

  16. The interpretation of hard X-ray polarization measurements in solar flares

    NASA Technical Reports Server (NTRS)

    Leach, J.; Petrosian, V.; Emslie, A. G.

    1985-01-01

    Observations of polarization of moderately hard X-rays in solar flares are reviewed and compared with the predictions of recent detailed modeling of hard X-ray bremsstrahlung production by non-thermal electrons. The recent advances in the complexity of the modeling lead to substantially lower predicted polarizations than in earlier models and more fully highlight how various parameters play a role in determining the polarization of the radiation field. The new predicted polarizations are comparable to those predicted by thermal modeling of solar flare hard X-ray production, and both are in agreement with the observations. In the light of these results, new polarization observations with current generation instruments are proposed which could be used to discriminate between non-thermal and thermal models of hard X-ray production in solar flares.

  17. The interpretation of hard X-ray polarization measurements in solar flares

    NASA Technical Reports Server (NTRS)

    Leach, J.; Emslie, A. G.; Petrosian, V.

    1983-01-01

    Observations of polarization of moderately hard X-rays in solar flares are reviewed and compared with the predictions of recent detailed modeling of hard X-ray bremsstrahlung production by non-thermal electrons. The recent advances in the complexity of the modeling lead to substantially lower predicted polarizations than in earlier models and more fully highlight how various parameters play a role in determining the polarization of the radiation field. The new predicted polarizations are comparable to those predicted by thermal modeling of solar flare hard X-ray production, and both are in agreement with the observations. In the light of these results, new polarization observations with current generation instruments are proposed which could be used to discriminate between non-thermal and thermal models of hard X-ray production in solar flares.

  18. Time Analysis of Hard Drive Imaging Tools

    Microsoft Academic Search

    Jack Wesley Riley; David A. Dampier; Rayford B. Vaughn

    2008-01-01

    Computer hard drives often contain evidence that is vital to digital forensic investigations. However, an authenticated working\\u000a copy or “forensic image” of a suspect hard drive must be created before any data can be analyzed. As the capacities of modern\\u000a hard drives increase, the time taken to create a forensic image, let alone analyze the data, increases significantly. This\\u000a paper

  19. Comparison of FDTD Hard Source With FDTD Soft Source and Accuracy Assessment in Debye Media

    Microsoft Academic Search

    Fumie Costen; Jean-Pierre Berenger; Anthony K. Brown

    2009-01-01

    To radiate electromagnetic energy from a single point of a finite difference time domain (FDTD) grid, there are typically two general classes of electromagnetic wave sources; the soft source which consists of impressing a current, and the hard source which consists of impressing an electric field. The physical meaning of the soft source is well understood and its analytical solution

  20. Atomic physics with hard X-rays from high brilliance synchrotron light sources

    SciTech Connect

    Southworth, S.; Gemmell, D.

    1996-08-01

    A century after the discovery of x rays, the experimental capability for studying atomic structure and dynamics with hard, bright synchrotron radiation is increasing remarkably. Tempting opportunities arise for experiments on many-body effects, aspects of fundamental photon-atom interaction processes, and relativistic and quantum-electrodynamic phenomena. Some of these possibilities are surveyed in general terms.

  1. Spectral features in solar hard x-ray and radio events and particle acceleration

    Microsoft Academic Search

    A. O. Benz

    1977-01-01

    Hard x-ray and radio intensities of two major solar outbursts are found to anticorrelate in time with their spectral indices, which, furthermore, are in satisfactory correlation with each other. The radio emission must be synchrotron radiation from the same electron population that causes the x-ray bremsstrahlung. A delay of temporal features, increasing with energy, is clearly observed in one of

  2. HARD X-RAY TAILS AND CYCLOTRON FEATURES IN X-RAY PULSARS

    E-print Network

    Orlandini, Mauro

    HARD X-RAY TAILS AND CYCLOTRON FEATURES IN X-RAY PULSARS Mauro Orlandini and Daniele Dal Fiume Te-fed binaries, or coming from an accretion disc due to Roche-lobe overflow -- disk-fed binaries) into radiation . The dipolar magnetic field of the NS drives the accreted matter onto the magnetic polar caps

  3. HARD X--RAY TAILS AND CYCLOTRON FEATURES IN X--RAY PULSARS

    E-print Network

    Orlandini, Mauro

    HARD X--RAY TAILS AND CYCLOTRON FEATURES IN X--RAY PULSARS Mauro Orlandini and Daniele Dal Fiume Te, or coming from an accretion disc due to Roche­lobe overflow --- disk­fed binaries) into radiation, because magnetic field of the NS drives the accreted matter onto the magnetic polar caps, and if the magnetic field

  4. Resummation for QCD Hard Scattering

    E-print Network

    Kidonakis, N; Kidonakis, Nikolaos; Sterman, George

    1997-01-01

    We resum distributions that are singular at partonic threshold (the elastic limit) in heavy quark production, in terms of logarithmic behavior in moment space. The method may be applied to a variety of cross sections sensitive to the edge of phase space, including transverse momentum distributions. Beyond leading logarithm, dependence on the moment variable is controlled by a matrix renormalization group equation, reflecting the evolution of composite operators that represent the color structure of the underlying hard scattering. At next-to-leading logarithmic accuracy, these evolution equations may be diagonalized, and moment dependence in the cross section is a sum of exponentials. Beyond next-to-leading logarithm, resummation involves matrix-ordering. We give a detailed analysis for the case of heavy quark production by light quark annihilation and gluon fusion.

  5. Electromagnetic Scattering from Foliage Camouflaged Hard Targets,

    E-print Network

    Sarabandi, Kamal

    Electromagnetic Scattering from Foliage Camouflaged Hard Targets, in VHF-band Mojtaba Dehmollaian. Then using this formulation, and single scattering theory the backscattered field from a camouflaged complex

  6. Interfacial free energy of a hard-sphere fluid in contact with curved hard surfaces

    E-print Network

    Laird, Brian Bostian; Hunter, Allie; Davidchack, Ruslan L.

    2012-12-20

    Using molecular-dynamics simulation, we have calculated the interfacial free energy ? between a hard-sphere fluid and hard spherical and cylindrical colloidal particles, as functions of the particle radius R and the fluid ...

  7. Solid-state radiation-emitting compositions and devices

    DOEpatents

    Ashley, C.S.; Brinker, C.J.; Reed, S.; Walko, R.J.

    1992-08-11

    The invention relates to a composition for the volumetric generation of radiation, wherein a first substance functions as a source of exciting radiation, and a second substance interacts with the exciting radiation to provide a second radiation. The compositions comprise a porous substrate which is loaded with: a source of exciting radiation, a component capable of emitting radiation upon interaction with the exciting radiation, or both. Preferably, the composition is an aerogel substrate loaded with both a source of exciting radiation, such as tritium, and a component capable of interacting with the exciting radiation, e.g., a phosphor, to produce radiation of a second energy. 4 figs.

  8. Solid-state radiation-emitting compositions and devices

    DOEpatents

    Ashley, Carol S. (Albuquerque, NM); Brinker, C. Jeffrey (Albuquerque, NM); Reed, Scott (Albuquerque, NM); Walko, Robert J. (Albuquerque, NM)

    1992-01-01

    The invention relates to a composition for the volumetric generation of radiation, wherein a first substance functions as a source of exciting radiation, and a second substance interacts with the exciting radiation to provide a second radiation. The compositions comprise a porous substrate which is loaded with: a source of exciting radiation, a component capable of emitting radiation upon interaction with the exciting radiation, or both. Preferably, the composition is an aerogel substrate loaded with both a source of exciting radiation, such as tritium, and a component capable of interacting with the exciting radiation, e.g., a phosphor, to produce radiation of a second energy.

  9. Radiation tolerant semiconductor sensors for tracking detectors

    Microsoft Academic Search

    2006-01-01

    The CERN RD50 collaboration ``Development of Radiation Hard Semiconductor Devices for Very High Luminosity Colliders'' is developing radiation tolerant tracking detectors for the upgrade of the Large Hadron Collider at CERN (Super-LHC). One of the main challenges arising from the target luminosity of 1035 cm-2 s-1 are the unprecedented high radiation levels. Over the anticipated 5 years lifetime of the

  10. Rolling-contact and wear resistance of hard coatings on bearing-steel substrates

    SciTech Connect

    Erdemir, A.

    1992-02-01

    Ever-increasing needs for high-performance ball- and roller-bearing components that can endure extreme applications have led to a growing interest in hard coatings for improved fatigue life and wear resistance. In particular, hard TiN and TiC coatings and, quite recently, diamond like carbon films have attracted much attention from manufacturers that produce bearing systems for both rolling- and sliding-contact applications. This paper presents an overview that highlights recent incremental progress in achieving improved fatigue and wear resistance in bearing steels through the use of hard coatings. Effects of coating adhesion, thickness, and morphology on fatigue and wear resistance of hard coatings are discussed in detail. Specific references are made to a few mechanistic models that correlate coating thickness and adhesion to improved fatigue life and wear resistance.

  11. Hard Gamma Ray Emission from the Starburst Galaxy NGC 253

    NASA Technical Reports Server (NTRS)

    Jackson, James M.; Marscher, Alan M.

    1996-01-01

    We have completed the study to search for hard gamma ray emission from the starburst galaxy NGC 253. Since supernovae are thought to provide the hard gamma ray emission from the Milky Way, starburst galaxies, with their extraordinarily high supernova rates, are prime targets to search for hard gamma ray emission. We conducted a careful search for hard gamma ray emission from NGC 253 using the archival data from the EGRET experiment aboard the CGRO. Because this starburst galaxy happens to lie near the South Galactic Pole, the Galactic gamma ray background is minimal. We found no significant hard gamma ray signal toward NGC 253, although a marginal signal of about 1.5 sigma was found. Because of the low Galactic background, we obtained a very sensitive upper limit to the emission of greater than 100 MeV gamma-rays of 8 x 10(exp -8) photons/sq cm s. Since we expected to detect hard gamma ray emission, we investigated the theory of gamma ray production in a dense molecular medium. We used a leaky-box model to simulate diffusive transport in a starburst region. Since starburst galaxies have high infrared radiation fields, we included the effects of self-Compton scattering, which are usually ignored. By modelling the expected gamma-ray and synchrotron spectra from NGC 253, we find that roughly 5 - 15% of the energy from supernovae is transferred to cosmic rays in the starburst. This result is consistent with supernova acceleration models, and is somewhat larger than the value derived for the Galaxy (3 - 10%). Our calculations match the EGRET and radio data very well with a supernova rate of 0.08/ yr, a magnetic field B approx. greater than 5 x 10(exp -5) G, a density n approx. less than 100/sq cm, a photon density U(sub ph) approx. 200 eV/sq cm, and an escape time scale tau(sub 0) approx. less than 10 Myr. The models also suggest that NGC 253 should be detectable with only a factor of 2 - 3 improvement in sensitivity. Our results are consistent with the standard picture of gamma-ray acceleration by supernovae.

  12. Hard X-ray Microscopic Imaging Of Human Breast Tissues

    NASA Astrophysics Data System (ADS)

    Park, Sung H.; Kim, Hong T.; Kim, Jong K.; Jheon, Sang H.; Youn, Hwa S.

    2007-01-01

    X-ray microscopy with synchrotron radiation will be a useful tool for innovation of x-ray imaging in clinical and laboratory settings. It helps us observe detailed internal structure of material samples non-invasively in air. And, it also has the potential to solve some tough problems of conventional breast imaging if it could evaluate various conditions of breast tissue effectively. A new hard x-ray microscope with a spatial resolution better than 100 nm was installed at Pohang Light Source, a third generation synchrotron radiation facility in Pohang, Korea. The x-ray energy was set at 6.95 keV, and the x-ray beam was monochromatized by W/B4C monochromator. Condenser and objective zone plates were used as x-ray lenses. Zernike phase plate next to condenser zone plate was introduced for improved contrast imaging. The image of a sample was magnified 30 times by objective zone plate and 20 times by microscope objective, respectively. After additional 10 times digital magnification, the total magnifying power was up to 6000 times in the end. Phase contrast synchrotron images of 10-?m-thick female breast tissue of the normal, fibroadenoma, fibrocystic change and carcinoma cases were obtained. By phase contrast imaging, hard x-rays enable us to observe many structures of breast tissue without sample preparations such as staining or fixation.

  13. GRB 060313: A New Paradigm for Short-Hard Bursts?

    E-print Network

    Peter W. A. Roming; Daniel Vanden Berk; Valentin Palshin; Claudio Pagani; Jay Norris; Pawan Kumar; Hans Krimm; Stephen T. Holland; Caryl Gronwall; A lex J. Blustin; Bing Zhang; Patricia Schady; Takanori Sakamoto; Julian P. Osborne; John A. Nousek; Frank E. Marshall; Peter Meszaros; Sergey V. Golenetskii; Neil Gehrels; Dmitry D. Frederiks; Sergio Campana; David N. Burrows; Patricia T. Boyd; Scott Barthelmy; R. L. Aptekar

    2006-08-03

    We report the simultaneous observations of the prompt emission in the gamma-ray and hard X-ray bands by the Swift-BAT and the KONUS-Wind instruments of the short-hard burst, GRB 060313. The observations reveal multiple peaks in both the gamma-ray and hard X-ray bands suggesting a highly variable outflow from the central explosion. We also describe the early-time observations of the X-ray and UV/Optical afterglows by the Swift XRT and UVOT instruments. The combination of the X-ray and UV/Optical observations provide the most comprehensive lightcurves to date of a short-hard burst at such an early epoch. The afterglows exhibit complex structure with different decay indices and flaring. This behavior can be explained by the combination of a structured jet, radiative loss of energy, and decreasing microphysics parameters occurring in a circum-burst medium with densities varying by a factor of approximately two on a length scale of 10^17 cm. These density variations are normally associated with the environment of a massive star and inhomogeneities in its windy medium. However, the mean density of the observed medium (n approximately 10^?4 cm^3) is much less than that expected for a massive star. Although the collapse of a massive star as the origin of GRB 060313 is unlikely, the merger of a compact binary also poses problems for explaining the behavior of this burst. Two possible suggestions for explaining this scenario are: some short bursts may arise from a mechanism that does not invoke the conventional compact binary model, or soft late-time central engine activity is producing UV/optical but no X-ray flaring.

  14. Effects of radiation on laser diodes.

    SciTech Connect

    Phifer, Carol Celeste

    2004-09-01

    The effects of ionizing and neutron radiation on the characteristics and performance of laser diodes are reviewed, and the formation mechanisms for nonradiative recombination centers, the primary type of radiation damage in laser diodes, are discussed. Additional topics include the detrimental effects of aluminum in the active (lasing) volume, the transient effects of high-dose-rate pulses of ionizing radiation, and a summary of ways to improve the radiation hardness of laser diodes. Radiation effects on laser diodes emitting in the wavelength region around 808 nm are emphasized.

  15. MAKING JAVA HARD REALTIME Peter Puschner

    E-print Network

    MAKING JAVA HARD REAL­TIME Peter Puschner Institut fË?ur Technische Informatik Technische Universit,andyg@cs.york.ac.uk ABSTRACT Due to its portability and security the Java program­ ming language has become very popular. Standard Java is however not suited for programming hard real­time sys­ tems. To overcome this limitation

  16. Hard Spring Wheat Technical Committee, 2008 Crop.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Eleven hard spring wheat lines that were developed by breeders throughout the spring wheat region of the U. S. were grown at up to five locations in 2008 and evaluated for kernel, milling, and bread baking quality against the check variety Glenn. Samples of wheat were milled at the USDA Hard Red Sp...

  17. Hard Metal Alveolitis Accompanied by Rheumatoid Arthritis

    Microsoft Academic Search

    Paula A. Hahtola; Ritva E. Järvenpää; Kari Lounatmaa; Jorma J. Mattila; Immo Rantala; Jukka A. Uitti; Seppo Sutinen

    2000-01-01

    Hard metal lung diseases (HML) are rare, and complex to diagnose. We describe the case of a patient with allergic alveolitis accompanied by rheumatoid arthritis. A sharpener of hard metal by trade, our patient was a 45-year-old, nonsmoking Caucasian female who experienced symptoms of cough and phlegm, and dyspnea on exertion. Preliminary lung findings were inspiratory rales in both basal

  18. Radiation dosimetry.

    PubMed Central

    Cameron, J

    1991-01-01

    This article summarizes the basic facts about the measurement of ionizing radiation, usually referred to as radiation dosimetry. The article defines the common radiation quantities and units; gives typical levels of natural radiation and medical exposures; and describes the most important biological effects of radiation and the methods used to measure radiation. Finally, a proposal is made for a new radiation risk unit to make radiation risks more understandable to nonspecialists. PMID:2040250

  19. Hard breakup of the deuteron into two ? isobars

    NASA Astrophysics Data System (ADS)

    Granados, Carlos G.; Sargsian, Misak M.

    2011-05-01

    We study high-energy photodisintegration of the deuteron into two ? isobars at large center of mass angles within the QCD hard rescattering model (HRM). According to the HRM, the process develops in three main steps: the photon knocks a quark from one of the nucleons in the deuteron; the struck quark rescatters off a quark from the other nucleon sharing the high energy of the photon; then the energetic quarks recombine into two outgoing baryons which have large transverse momenta. Within the HRM, the cross section is expressed through the amplitude of pn??? scattering which we evaluated based on the quark-interchange model of hard hadronic scattering. Calculations show that the angular distribution and the strength of the photodisintegration is mainly determined by the properties of the pn??? scattering. We predict that the cross section of the deuteron breakup to ?++?- is 4-5 times larger than that of the breakup to the ?+?0 channel. Also, the angular distributions for these two channels are markedly different. These can be compared with the predictions based on the assumption that two hard ? isobars are the result of the disintegration of the preexisting ?? components of the deuteron wave function. In this case, one expects the angular distributions and cross sections of the breakup in both ?++?- and ?+?0 channels to be similar.

  20. Hard breakup of the deuteron into two ? -isobars

    NASA Astrophysics Data System (ADS)

    Granados, Carlos; Sargsian, Misak

    2011-04-01

    Photodisintegration of the deuteron into two ?-isobars at large center of mass angles is studied within the QCD hard rescattering model (HRM). According to the HRM, the reaction proceeds in three main steps: the photon knocks the quark from one of the nucleons in the deuteron; the struck quark rescatters off a quark from the other nucleon sharing the high energy of the photon; then the energetic quarks recombine into two outgoing baryons emerging at large transverse momenta. Within the HRM, the cross section is expressed through the amplitude of pn --> ?? scattering which we evaluated based on the quark-interchange model of hard hadronic scattering. We predict that the cross section of the deuteron breakup to ?++?- is 4-5 times larger than that of the breakup to the ?+?0 channel. Also, the angular distributions for these two channels are markedly different. These can be compared with the predictions based on the assumption that two hard ?-isobars are the result of the disintegration of initial ?? components of the deuteron wave function. In this case, the angular distributions and cross sections of the breakup in both ?++?- and ?+?0 channels are expected to be similar. This work was supported by U.S. Department of Energy Grant under contract DE-FG02-01ER41172, and by the FIU DEA program.

  1. Theory of asymmetric nonadditive binary hard-sphere mixtures.

    PubMed

    Roth, R; Evans, R; Louis, A A

    2001-11-01

    It is shown that the formal procedure of integrating out the degrees of freedom of the small spheres in a binary hard-sphere mixture works equally well for nonadditive as it does for additive mixtures. For highly asymmetric mixtures (small size ratios) the resulting effective Hamiltonian of the one-component fluid of big spheres, which consists of an infinite number of many-body interactions, should be accurately approximated by truncating after the term describing the effective pair interaction. Using a density functional treatment developed originally for additive hard-sphere mixtures the zero, one, and two-body contribution to the effective Hamiltonian are determined. It is demonstrated that even small degrees of positive or negative nonadditivity have significant effect on the shape of the depletion potential. The second virial coefficient B2, corresponding to the effective pair interaction between two big spheres, is found to be a sensitive measure of the effects of nonadditivity. The variation of B2 with the density of the small spheres shows significantly different behavior for additive, slightly positive and slightly negative nonadditive mixtures. Possible repercussions of these results for the phase behavior of binary hard-sphere mixtures are discussed and it is suggested that measurements of B2 might provide a means of determining the degree of nonadditivity in real colloidal mixtures. PMID:11735911

  2. Hard-body models of bulk liquid crystals

    NASA Astrophysics Data System (ADS)

    Mederos, Luis; Velasco, Enrique; Martínez-Ratón, Yuri

    2014-11-01

    Hard models for particle interactions have played a crucial role in the understanding of the structure of condensed matter. In particular, they help to explain the formation of oriented phases in liquids made of anisotropic molecules or colloidal particles and continue to be of great interest in the formulation of theories for liquids in bulk, near interfaces and in biophysical environments. Hard models of anisotropic particles give rise to complex phase diagrams, including uniaxial and biaxial nematic phases, discotic phases and spatially ordered phases such as smectic, columnar or crystal. Also, their mixtures exhibit additional interesting behaviours where demixing competes with orientational order. Here we review the different models of hard particles used in the theory of bulk anisotropic liquids, leaving aside interfacial properties and discuss the associated theoretical approaches and computer simulations, focusing on applications in equilibrium situations. The latter include one-component bulk fluids, mixtures and polydisperse fluids, both in two and three dimensions, and emphasis is put on liquid-crystal phase transitions and complex phase behaviour in general.

  3. Hard-body models of bulk liquid crystals.

    PubMed

    Mederos, Luis; Velasco, Enrique; Martínez-Ratón, Yuri

    2014-11-19

    Hard models for particle interactions have played a crucial role in the understanding of the structure of condensed matter. In particular, they help to explain the formation of oriented phases in liquids made of anisotropic molecules or colloidal particles and continue to be of great interest in the formulation of theories for liquids in bulk, near interfaces and in biophysical environments. Hard models of anisotropic particles give rise to complex phase diagrams, including uniaxial and biaxial nematic phases, discotic phases and spatially ordered phases such as smectic, columnar or crystal. Also, their mixtures exhibit additional interesting behaviours where demixing competes with orientational order. Here we review the different models of hard particles used in the theory of bulk anisotropic liquids, leaving aside interfacial properties and discuss the associated theoretical approaches and computer simulations, focusing on applications in equilibrium situations. The latter include one-component bulk fluids, mixtures and polydisperse fluids, both in two and three dimensions, and emphasis is put on liquid-crystal phase transitions and complex phase behaviour in general. PMID:25335432

  4. 1987 Annual Conference on Nuclear and Space Radiation Effects, Snowmass Village, CO, July 28-31, 1987, Proceedings

    NASA Technical Reports Server (NTRS)

    1987-01-01

    Various papers on nuclear and space radiation effects are presented. The general topics addressed include: basic mechanisms of radiation effects, single-event phenomena, temperature and field effects, modeling and characterization of radiation effects, IC radiation effects and hardening, and EMP/SGEMP/IEMP phenomena. Also considered are: dosimetry/energy-dependent effects, sensors in and for radiation environments, spacecraft charging and space radiation effects, radiation effects and devices, radiation effects on isolation technologies, and hardness assurance and testing techniques.

  5. Phase diagram of hard tetrahedra.

    PubMed

    Haji-Akbari, Amir; Engel, Michael; Glotzer, Sharon C

    2011-11-21

    Advancements in the synthesis of faceted nanoparticles and colloids have spurred interest in the phase behavior of polyhedral shapes. Regular tetrahedra have attracted particular attention because they prefer local symmetries that are incompatible with periodicity. Two dense phases of regular tetrahedra have been reported recently. The densest known tetrahedron packing is achieved in a crystal of triangular bipyramids (dimers) with a packing density of 4000/4671 ? 85.63%. In simulation a dodecagonal quasicrystal is observed; its approximant, with periodic tiling (3.4.3(2).4), can be compressed to a packing fraction of 85.03%. Here, we show that the quasicrystal approximant is more stable than the dimer crystal for packing densities below 84% using Monte Carlo computer simulations and free energy calculations. To carry out the free energy calculations, we use a variation of the Frenkel-Ladd method for anisotropic shapes and thermodynamic integration. The enhanced stability of the approximant can be attributed to a network substructure, which maximizes the free volume (and hence the wiggle room) available to the particles and facilitates correlated motion of particles, which further contributes to entropy and leads to diffusion for packing densities below 65%. The existence of a solid-solid transition between structurally distinct phases not related by symmetry breaking--the approximant and the dimer crystal--is unusual for hard particle systems. PMID:22112060

  6. Phase Diagram of Hard Tetrahedra

    E-print Network

    Amir Haji-Akbari; Michael Engel; Sharon C. Glotzer

    2011-11-22

    Advancements in the synthesis of faceted nanoparticles and colloids have spurred interest in the phase behavior of polyhedral shapes. Regular tetrahedra have attracted particular attention because they prefer local symmetries that are incompatible with periodicity. Two dense phases of regular tetrahedra have been reported recently. The densest known tetrahedron packing is achieved in a crystal of triangular bipyramids (dimers) with packing density 4000/4671=85.63%. In simulation a dodecagonal quasicrystal is observed; its approximant, with periodic tiling (3.4.3^2.4), can be compressed to a packing fraction of 85.03%. Here, we show that the quasicrystal approximant is more stable than the dimer crystal for packing densities below 84% using Monte Carlo computer simulations and free energy calculations. To carry out the free energy calculations, we use a variation of the Frenkel-Ladd method for anisotropic shapes and thermodynamic integration. The enhanced stability of the approximant can be attributed to a network substructure, which maximizes the free volume (and hence the 'wiggle room') available to the particles and facilitates correlated motion of particles, which further contributes to entropy and leads to diffusion for packing densities below 65%. The existence of a solid-solid transition between structurally distinct phases not related by symmetry breaking -- the approximant and the dimer crystal-- is unusual for hard particle systems.

  7. Radiation Monitoring Equipment Dosimeter Experiment

    NASA Technical Reports Server (NTRS)

    Hardy, Kenneth A.; Golightly, Michael J.; Quam, William

    1992-01-01

    Spacecraft crews risk exposure to relatively high levels of ionizing radiation. This radiation may come from charged particles trapped in the Earth's magnetic fields, charged particles released by solar flare activity, galactic cosmic radiation, energetic photons and neutrons generated by interaction of these primary radiations with spacecraft and crew, and man-made sources (e.g., nuclear power generators). As missions are directed to higher radiation level orbits, viz., higher altitudes and inclinations, longer durations, and increased flight frequency, radiation exposure could well become a major factor for crew stay time and career lengths. To more accurately define the radiological exposure and risk to the crew, real-time radiation monitoring instrumentation, which is capable of identifying and measuring the various radiation components, must be flown. This presentation describes a radiation dosimeter instrument which was successfully flown on the Space Shuttle, the RME-3.

  8. Radiation effects on semiconductor optical devices for space communications

    Microsoft Academic Search

    L. W. Aukerman; Y. Song; F. L. Vernon Jr.; G. A. Evans; J. Z. Wilcox

    1982-01-01

    A survey of the published literature on radiation effects in laser diodes and photodiodes as applied to space communications is presented. Laser diodes should be relatively hard to nuclear environments, especially if operated well above threshold, and should be quite hard to the natural environment. Photodiodes, on the other hand, may experience excess noise due to sustained ionization by Van

  9. Revisit of interfacial free energy of the hard sphere system near hard wall

    E-print Network

    Mingcheng Yang; Hongru Ma

    2008-06-23

    We propose a simple Monte Carlo method to calculate the interfacial free energy between the substrate and the material. Using this method we investigate the interfacial free energys of the hard sphere fluid and solid phases near a smooth hard wall. According to the obtained interfacial free energys of the coexisting fluid and solid phases and the Young equation we are able to determine the contact angle with high accuracy, cos$\\theta$ = 1:010(31), which indicates that a smooth hard wall can be wetted completely by the hard sphere crystal at the interface between the wall and the hard sphere fluid.

  10. Hard X-ray Emission and Efficient Particle Acceleration by Supernova Remnants

    NASA Astrophysics Data System (ADS)

    Vink, Jacco

    2009-05-01

    I discuss the non-thermal X-ray emission from young supernova remnants. Over the last decade it has become clear from both X-ray and ?-ray observations that young supernovae accelerate particles up to 100 TeV. In soft X-rays the accelerated >10 TeV electrons produce synchrotron radiation, coming from narrow filaments located at the shock fronts. The width of these filaments shows that the magnetic fields are relatively high, thus providing evidence for magnetic field amplification. The synchrotron radiation of several remnants is known to extend into the hard X-ray regime. In particular Cas A, has a spectrum that appears as a power law up to almost 100 TeV. This is very surprising, as a steepening is expected going from the soft to the hard X-ray band. The spectrum is likely a result of many superimposed individual spectra, each steepening at different energies. This implies considerable spatial variation in hard X-rays, an obvious target for Simbol-X. The variations will be important to infer local shock acceleration properties, but also magnetic field fluctuations may cause spatial and temporal variations. Finally, I draw the attention to super bubbles and supernovae as sources of cosmic rays. As such they may be sources of hard X-ray emission. In particular, supernovae exploding inside the dense red supergiants winds of their progenitors ares promising candidates for hard X-ray emission.

  11. HEXTE Studies of Hard X-Ray Tails in Sco X-1

    Microsoft Academic Search

    F. D'Amico; W. Heindl; R. E. Rothschild; D. Gruber

    2000-01-01

    We report the detection of a non-thermal hard X-ray component from Sco X--1 based upon the analysis of 20-220 keV spectra obtained with the HEXTE experiment onboard the RXTE satellite. We find that that the addition of a power-law component to a thermal bremmstrahlung model is required to achieve a good fit in some observations. Using PCA data we were

  12. Radiation hardening of diagnostics for fusion reactors

    SciTech Connect

    Baur, J.F.; Engholm, B.A.; Hacker, M.P.; Maya, I.; Miller, P.H.; Toffolo, W.E.; Wojtowicz, S.S.

    1981-12-01

    A list of the diagnostic systems presently used in magnetic confinement fusion experiments is compiled herein. The radiation-sensitive components are identified, and their locations in zones around the machine are indicated. A table of radiation sensitivities of components is included to indicate the data available from previous work in fission reactor, space probe, and defense-related programs. Extrapolation and application to hardening of fusion diagnostic systems requires additional data that are more specific to the fusion radiation environment and fusion components. A list is also given of present radiation-producing facilities where near-term screening tests of materials and components can be performed.

  13. Reconfigurable, Bi-Directional Flexfet Level Shifter for Low-Power, Rad-Hard Integration

    NASA Technical Reports Server (NTRS)

    DeGregorio, Kelly; Wilson, Dale G.

    2009-01-01

    Two prototype Reconfigurable, Bi-directional Flexfet Level Shifters (ReBiLS) have been developed, where one version is a stand-alone component designed to interface between external low voltage and high voltage, and the other version is an embedded integrated circuit (IC) for interface between internal low-voltage logic and external high-voltage components. Targeting stand-alone and embedded circuits separately allows optimization for these distinct applications. Both ReBiLS designs use the commercially available 180-nm Flex fet Independently Double-Gated (IDG) SOI CMOS (silicon on insulator, complementary metal oxide semiconductor) technology. Embedded ReBiLS circuits were integrated with a Reed-Solomon (RS) encoder using CMOS Ultra-Low-Power Radiation Tolerant (CULPRiT) double-gated digital logic circuits. The scope of the project includes: creation of a new high-voltage process, development of ReBiLS circuit designs, and adjustment of the designs to maximize performance through simulation, layout, and manufacture of prototypes. The primary technical objectives were to develop a high-voltage, thick oxide option for the 180-nm Flexfet process, and to develop a stand-alone ReBiLS IC with two 8-channel I/O busses, 1.8 2.5 I/O on the low-voltage pins, 5.0-V-tolerant input and 3.3-V output I/O on the high-voltage pins, and 100-MHz minimum operation with 10-pF external loads. Another objective was to develop an embedded, rad-hard ReBiLS I/O cell with 0.5-V low-voltage operation for interface with core logic, 5.0-V-tolerant input and 3.3-V output I/O pins, and 100-MHz minimum operation with 10- pF external loads. A third objective was to develop a 0.5- V Reed-Solomon Encoder with embedded ReBilS I/O: Transfer the existing CULPRiT RS encoder from a 0.35-micron bulk-CMOS process to the ASI 180-nm Flexfet, rad-hard SOI Process. 0.5-V low-voltage core logic. 5.0-V-tolerant input and 3.3-V output I/O pins. 100-MHz minimum operation with 10- pF external loads. The stand-alone ReBiLS chip will allow system designers to provide efficient bi-directional communication between components operating at different voltages. Embedding the ReBiLS cells into the proven Reed-Solomon encoder will demonstrate the ability to support new product development in a commercially viable, rad-hard, scalable 180-nm SOI CMOS process.

  14. Closing a Resource Room for Students Who Are Deaf or Hard of Hearing

    ERIC Educational Resources Information Center

    Miller, Kevin J.

    2008-01-01

    Self-contained classrooms and resource rooms have been an important component of the continuum of placements available to students who are deaf or hard of hearing. However, these specialized classrooms have been closing in recent years. A variety of factors are contributing to this, most notably the impact of cochlear implants. This article…

  15. Experience in Manufacture of Hard Waxes. Combined Dewaxing and Deoiling Unit

    Microsoft Academic Search

    I. N. Kachlishvili; T. F. Filippova

    2003-01-01

    Most of the country's oil units are primarily oriented toward production of lube oils. The by–products formed are used as components of furnace residual fuel oil. Even the slack wax obtained in dewaxing of selectively refined raffinates goes into furnace residual fuel oil. The slack wax contains from 80 to 90% hard waxes which, like dewaxed oil, are a valuable

  16. Production by various methods of composite materials based on a hard metal with cubic boron nitride

    Microsoft Academic Search

    V. D. Andreev; V. P. Bondarenko; A. M. Baranovskii; V. P. Pereyaslov; V. P. Kolomiets; I. V. Manzheleev; N. I. Chukhno

    1983-01-01

    During the production of the composite materials under consideration by orthodox sintering the cubic boron nitride and hard metal react with each other, with the formation of borides and appearance of porosity as a result of the evolution of gaseous reaction products, and the strength of the materials is therefore low. During hot pressing the reaction between the components of

  17. Isolation of Cholesterol from Egg Yolk Preparation: Bring a hard-boiled egg yolk to lab!

    E-print Network

    Taber, Douglass

    Isolation of Cholesterol from Egg Yolk Preparation: Bring a hard-boiled egg yolk to lab! Cholesterol (1) is a major component of cell membranes. An egg yolk contains about 200 milligrams of cholesterol, much of it bound as complex lipid. In this experiment, you will purify cholesterol from an egg

  18. Sensors Hard-Failure Diagnosis of Engine Control System Based Accommodation Kalman Filter

    Microsoft Academic Search

    Xu Xiuling; Wang Xiaodong

    2010-01-01

    In recent years, Full-Authority Digital Electronic Control (FADEC) system needs some component redundancy in order to attain sufficient reliability. So sensors failure diagnosis method is developed in this paper. Accommodation filters have been used in hard-failure and simulations have been done in fault sensors in the paper. From the simulation results, the conclusion can be deduced that the fault diagnosis

  19. FINITE ELEMENT ANALYSIS OF FLEXURAL VIBRATIONS IN HARD DISK DRIVE SPINDLE SYSTEMS

    Microsoft Academic Search

    Seungchul Lim

    2000-01-01

    This paper is concerned with the flexural vibration analysis of the hard disk drive (HDD) spindle system by means of the finite element method. In contrast to previous research, every system component is here analytically modelled taking into account its structural flexibility and also the centrifugal effect particularly on the disk. To prove the effectiveness and accuracy of the formulated

  20. Adaptive and Optimal Rejection of Non-Repeatable Disturbance in Hard Disk Drives

    Microsoft Academic Search

    Young-Hoon Kim; Chang-Ik Kang; Masayoshi Tomizuka

    2005-01-01

    This paper presents an efficient control strategy to reduce the non-repeatable position error signal (PES) components caused by mechanical vibration in hard disk drives. A peak filter is designed that plugs into a servo loop in parallel with the existing controller. Based on the PES, the filter's center frequency is adaptively searched for in order to identify a dominant spectral

  1. Shock modeling of the head-media interface in an operational hard disk drive

    Microsoft Academic Search

    Eric M. Jayson; Paul W. Smith; Frank E. Talke

    2003-01-01

    A complete model of an operational hard disk drive (HDD) subject to shock loads is developed to investigate the response of the head\\/media interface. The model is a coupled solution of the structural components and the hydrodynamic lubrication between the magnetic recording head and the disk surface. The structural model is a finite element simulation of the HDD using commercially

  2. Effects of formulation conditions on micellar interactions and solution rheology in multi-component micellar systems

    E-print Network

    Nachbar, Leslie Sarah

    2011-01-01

    Surfactants are crucial to the personal care industry due to their unique surface activity, cleansing, and self assembly properties. Typically, multi-component systems are used in order to maximize mildness, hard water ...

  3. Hardness of oxynitride glasses: topological origin.

    PubMed

    Paraschiv, Georgiana L; Gomez, Sinue; Mauro, John C; Wondraczek, Lothar; Yue, Yuanzheng; Smedskjaer, Morten M

    2015-03-12

    Oxynitride glasses are mixed-anion systems, in which the 2-fold coordinated oxygen atoms have been partially substituted by 3-fold coordinated nitrogen atoms. This so-called nitridation process introduces additional bonds and thereby constrains and compacts the glass network and consequently alters the glass hardness. To explore how and why hardness varies with the degree of nitridation, we have derived a topological model of oxynitride glass hardness using temperature-dependent constraint theory, by which the scaling of glass hardness with nitrogen content can be predicted. A linear model has been derived based on the assumption that the substitution of oxygen atoms with nitrogen atoms is responsible for the hardness increase due to the increase in the number (n) of bond-bending and bond-angular constraints. It turns out that the model agrees with the experimental observation, i.e., an approximate positive linear trend of the hardness change with nitrogen content is observed for a wide range of glass compositions. The topological model may thus be useful for designing new oxynitride glass compositions with targeted hardness values. PMID:25692458

  4. View factors between APT target components

    SciTech Connect

    Kidman, R.B.

    1998-07-01

    In a loss-of-coolant accident (LOCA) in the accelerator production of tritium (APT) target/blanket, radiation heat transfer determines the temperature of the target components. Radiation heat-transfer analysis can only proceed if accurate component-to-component view factors are available. The authors describe and demonstrate the numerical method used to compute the view factors (also called angle factors, configuration factors, and shape factors) between complicated objects. The method is verified on simple objects that have analytic solutions, and then it is used to predict the view factors between the target components of the accelerator production of tritium target/blanket. The method is practical, easy to apply, and can accommodate difficult levels of realism.

  5. Hard X-ray spatial array diagnostics on Joint Texas Experimental Tokamak.

    PubMed

    Huang, D W; Chen, Z Y; Luo, Y H; Tong, R H; Yan, W; Jin, W; Zhuang, G

    2014-11-01

    A spatially distributed hard X-ray detection array has been developed to diagnose the loss of runaway electron with toroidal and poloidal resolution. The hard X-ray radiation in the energy ranges of 0.3-1 MeV resulted from runaway electrons can be measured. The detection array consists of 12 CdTe detectors which are arranged surrounding the tokamak. It is found that most runaway electrons which transport to plasma boundary tend to loss on limiters. The application of electrode biasing probe resulted in enhancement of local runaway loss. Resonant magnetic perturbations enhanced the runaway electrons diffusion and showed an asymmetric poloidal loss rate. PMID:25430258

  6. Planar magnetic component development

    Microsoft Academic Search

    Robert L. Nagel; Michael E. Partridge

    1994-01-01

    Although planar magnetic components are relatively new, the technology offers several advantages. Component properties show less variation because the construction technique keeps the winding in the same relative position each time, and batch processes can be used if the components are all formed on one printed circuit board panel. Assembly is simplified, and labor is reduced. If the component windings

  7. COMPONENT User's Guide Introduction

    E-print Network

    Page, Roderic

    COMPONENT User's Guide Chapter 0 Introduction This chapter provides an overview of COMPONENT the distribution of bootstrap trees n computing distributions of tree comparison measures n comparing distributions;0-2 Introduction COMPONENT User's Guide Overview of features COMPONENT is a standard Microsoft® Windows

  8. Hard X ray imaging telescope

    NASA Astrophysics Data System (ADS)

    Lubin, P.

    1990-03-01

    This final report covers the work carried out under the LLNL Contract Number B063682, Subcontractor Regents University of California at Santa Barbara. The research carried out under this contract involves the construction of a telemetry, target acquisition and guidance system, and of a light-weight gondola to house an x ray spectrometer. This work is part of the design and construction of the balloon experiment, GRATIS, which will perform the first arcminute imaging of cosmic sources in the 30 to 200 keV energy band. Observations conducted with GRATIS are expected to provide data relevant to several key problems in high energy astrophysics including the physical processes responsible for the high energy tail observed in the soft gamma-ray spectra of clusters of galaxies and the origin of both the diffuse and point source components of the gamma-ray emission from the Galactic Center. This report discusses the scientific motivations for this experiment, presents several aspects of the design and construction of the hardware components, gives an overview of the stabilized platform, and demonstrates the expected performance and sensitivity.

  9. Galactic Black Holes in the Hard State: A Multi-Wavelength View of Accretion and Ejection

    NASA Technical Reports Server (NTRS)

    Kalemci; Tomsick, John A.; Migliari; Corbel; Markoff

    2010-01-01

    The canonical hard state is associated with emission from all three fundamental accretion components: the accretion disk, the hot accretion disk corona and the jet. On top of these, the hard state also hosts very rich temporal variability properties (low frequency QPOs in the PDS, time lags, long time scale evolution). Our group has been working on the major questions of the hard state both observationally (with mult i-wavelength campaigns using RXTE, Swift, Suzaku, Spitzer, VLA, ATCA, SMARTS) and theoretically (through jet models that can fit entire SEDs). Through spectral and temporal analysis we seek to determine the geometry of accretion components, and relate the geometry to the formation and emission from a jet. In this presentation I will review the recent contributions of our group to the field, including the Swift results on the disk geometry at low accretion rates, the jet model fits to the hard state SEDs (including Spitzer data) of GRO J1655-40, and the final results on the evolution of spectral (including X-ray, radio and infrared) and temporal properties of elected black holes in the hard states. I will also talk about impact of ASTROSAT to the science objective of our group.

  10. Electronic Teaching: Hard Disks and Networks.

    ERIC Educational Resources Information Center

    Howe, Samuel F.

    1984-01-01

    Describes floppy-disk and hard-disk based networks, electronic systems linking microcomputers together for the purpose of sharing peripheral devices, and presents points to remember when shopping for a network. (MBR)

  11. Novel hard compositions and methods of preparation

    DOEpatents

    Sheinberg, H.

    1981-02-03

    Novel very hard compositions of matter are prepared by using in all embodiments only a minor amount of a particular carbide (or materials which can form the carbide in situ when subjected to heat and pressure); and no strategic cobalt is needed. Under a particular range of conditions, densified compositions of matter of the invention are prepared having hardnesses on the Rockwell A test substantially equal to the hardness of pure tungsten carbide and to two of the hardest commercial cobalt-bonded tungsten carbides. Alternately, other compositions of the invention which have slightly lower hardnesses than those described above in one embodiment also possess the advantage of requiring no tungsten and in another embodiment possess the advantage of having a good fracture toughness value.

  12. One-dimensional gas of hard needles

    E-print Network

    Kardar, Mehran

    We study a one-dimensional gas of needlelike objects as a testing ground for a formalism that relates the thermodynamic properties of “hard” potentials to the probabilities for contacts between particles. Specifically, we ...

  13. [Solar radiation--physicochemical aspects].

    PubMed

    De Lima, J J

    1992-09-01

    The solar radiation spectrum and the properties of its components are studied in the present paper. The history of the sun rays before reaching earth surface is analysed. A simplified analysis of the interaction mechanisms of these components with molecules, the energy absorption capabilities of the latter and the expected biological consequences are considered. Special emphasis are given to the properties of ultra-violet and infra-red radiations and their production considered. PMID:1442194

  14. Hard and flexible optical printed circuit board

    Microsoft Academic Search

    El-Hang Lee; Hyun Sik Lee; S. G. Lee; B. H. O; S. G. Park; K. H. Kim

    2007-01-01

    We report on the design and fabrication of hard and flexible optical printed circuit boards (O-PCBs). The objective is to realize generic and application-specific O-PCBs, either in hard form or flexible form, that are compact, light-weight, low-energy, high-speed, intelligent, and environmentally friendly, for low-cost and high-volume universal applications. The O-PCBs consist of 2-dimensional planar arrays of micro\\/nano-scale optical wires, circuits

  15. EMP simulation for hardness verification testing

    NASA Astrophysics Data System (ADS)

    Beilfuss, J.; Capobianco, J.; Gray, R.

    A serious problem in the development of NEMP (nuclear electromagnetic pulse)-hardened systems is lack of adequate verification testing of the system hardness. The authors describe the development and use of a direct injection system designed specifically for threat-level hardness verification testing of complex systems with a number of electronic shelters interconnected by cables. Details of the theory and design of the synchronous injection system are presented. Experimental results related to the validity of the simulation technique are included.

  16. A Novel Approach to Hardness Testing

    NASA Technical Reports Server (NTRS)

    Spiegel, F. Xavier; West, Harvey A.

    1996-01-01

    This paper gives a description of the application of a simple rebound time measuring device and relates the determination of relative hardness of a variety of common engineering metals. A relation between rebound time and hardness will be sought. The effect of geometry and surface condition will also be discussed in order to acquaint the student with the problems associated with this type of method.

  17. Weakly Hard Real-Time Systems

    Microsoft Academic Search

    Guillem Bernat; Alan Burns; Albert Llamosí

    2001-01-01

    In a hard real-time system it is assumed that no deadline is missed, whereas in a softor rm real-time system deadlines can be missed, although, this usually happens in a nonpredictableway. However, most hard real-time systems could miss some deadlines providedthat it happens in a known and predictable way. Also adding predictability on the patternof missed deadlines for soft and

  18. Survey of interferometric techniques used to test JWST optical components

    Microsoft Academic Search

    H. Philip Stahl; Chris Alongi; Andrea Arneson; Rob Bernier; Bob Brown; Dave Chaney; Glen Cole; Jay Daniel; Lee Dettmann; Ron Eng; Ben Gallagher; Robert Garfield; James Hadaway; Patrick Johnson; Allen Lee; Doug Leviton; Adam Magruder; Michael Messerly; Ankit Patel; Pat Reardon; John Schwenker; Martin Seilonen; Koby Smith; W. Scott Smith

    2010-01-01

    JWST optical component in-process optical testing and cryogenic requirement compliance certification, verification & validation is probably the most difficult metrology job of our generation in astronomical optics. But, the challenge has been met: by the hard work of dozens of optical metrologists; the development and qualification of multiple custom test setups; and several new inventions, including 4D PhaseCam and Leica

  19. Reversible Integer Principal Component Transform for Hyperspectral Imagery Lossless Compression

    Microsoft Academic Search

    Xin Luo; Lei Guo; Zhen Liu

    2007-01-01

    Hyperspectral imagery has very high spectral and spatial correlations. The principal component transform (PCT) is theoretically the optimal transform to decorrelate hyperspectral data. However, since its transformed signal is real number, PCT is hardly applied in the field of lossless compression. The integer PCT based on factorization of the transform matrix in triangular elementary reversible matrices (TERM) is computed in

  20. SATenstein: Automatically Building Local Search SAT Solvers from Components

    Microsoft Academic Search

    Ashiqur R. Khudabukhsh; Lin Xu; Holger H. Hoos; Kevin Leyton-brown

    2009-01-01

    Designing high-performance algorithms for computation- ally hard problems is a difficult and often time-consuming task. In this work, we demonstrate that this task can be automated in the context of stochastic local search (SLS) solvers for the propositional satisfiability problem (SAT). We first introduce a generalised, highly param- eterised solver framework, dubbed SATenstein, that in- cludes components gleaned from or