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1

Neutron radiation hardness of vacuum compatible two-component adhesives  

NASA Astrophysics Data System (ADS)

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.

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

2009-04-01

2

Hard Solar Flare Radiations  

NASA Astrophysics Data System (ADS)

The space craft measurements during a solar flare demonstrate that electron precipitation with energy up to hundreds keV along the magnetic field lines to solar surface takes place. Precipitation of these particles on the solar surface is analogous with particle precipitation in aurora, but the energy in aurora is not so big. The thermal source of X-ray radiation in the corona appears above an active region. Such scenario of the flare is explained by electrodynamical solar flare model based on 3D MHD numerical simulation that demonstrate the energy accumulated in a current sheet can exceed 1e32 erg. The coronal source appears in the current sheet during fast energy release due to magnetic reconnection. The electron beams are accelerated in the field-aligned currents that generated by the Hall electric field produced in the current sheet. The development of neutron monitor data demonstrates two components of solar cosmic rays. The prompt cosmic ray component is generated during main energy release. This component consists of protons moving along the interplanetary magnetic lines. The exponential spectrum of these protons is in agreement with particle acceleration by the Lorenz electric field along the magnetic singular line in a current sheet. The similar effect has been observed in the laboratory experiments with high power discharge - pinch discharge. The similarity and difference of particle acceleration in a linear pinch effect and in the current sheet is discussed. The flares produce also a delayed component with power spectrum E^{-gamma} with gamma ~ 5. Such big gamma is difficult to explain by acceleration in a shock. Apparently, the delayed component spectrum is formed during particle diffusion in the turbulent magnetic field.

Podgorny, I.; Podgorny, A.; Vashenyuk, E.

2008-09-01

3

Impact of aging on radiation hardness  

SciTech Connect

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.

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

1997-07-01

4

Radiation-Hardness Data For Semiconductor Devices  

NASA Technical Reports Server (NTRS)

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.

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

1984-01-01

5

Determination of hardness and hardness penetration depth of metal components by Non Linear Harmonics Analysis  

NASA Astrophysics Data System (ADS)

For the characterization of steel quality, hardness is a very important parameter. The magneto-inductive Non Linear Harmonics Analysis (NLHA) has been developed and used as a non destructive technique for measuring core hardness, surface hardness and hardness penetration depth of steel components. A description of the working principle of NLHA is given together with the setup of a typical hardness measuring system. Examples are given for the determination of carbon content in steel foils, measurement of core hardness in gear bolts where the hardness was controlled by tempering. Further results demonstrate measurements of core hardness, surface hardness and hardness penetration depth of nitration hardened steel samples. The final example shows a hardness profile of a case hardened shaft.

Stegemann, D.; Reimche, W.; Feiste, K. L.; Reichert, Ch.; Marques-Fetter, P.

1999-12-01

6

Radiation-hard static induction transistor  

NASA Astrophysics Data System (ADS)

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

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

1988-12-01

7

Development of radiation hard scintillators  

SciTech Connect

The authors have demonstrated that the radiation stability of scintillators made from styrene polymer is very much improved by compounding with pentaphenyltrimethyltrisiloxane (DC 705 vacuum pump oil). The resulting scintillators are softer than desired, so they decided to make the scintillators directly from monomer where the base resin could be easily crosslinked to improve the mechanical properties. They can now demonstrate that scintillators made directly from the monomer, using both styrene and 4-methyl styrene, are also much more radiation resistant when modified with DC705 oil. In fact, they retain from 92% to 95% of their original light output after gamma irradiation to 10 Mrads in nitrogen with air annealing. When these scintillators made directly from monomer are compared with scintillators of the same composition made from polymer the latter have much higher light outputs. They commonly reach 83% while those made form monomer give only 50% to 60% relative to the reference, BC408. When oil modified scintillators using both p-terphenyl and tetraphenylbutadiene are compared with identical scintillators except that they use 3 hydroxy-flavone as the only luminophore the radiation stability is the same. However the 3HF system gives only 30% as much light as BC408 instead of 83% when both are measured with a green extended Phillips XP2081B phototube.

Markley, F.; Davidson, M.; Keller, J.; Foster, G.; Pla-Dalmau, A. [Fermi National Accelerator Lab., Batavia, IL (United States); Harmon, J.; Biagtan, E.; Schueneman, G. [Univ. of Florida, Gainesville, FL (United States). Physics Dept.; Senchishin, V. [Inst. for Single Crystals, Kharkov (Ukraine); Gustfason, H.; Rivard, M. [Univ. of Michigan, Ann Arbor, MI (United States)

1993-11-01

8

Radiation hardness assurances categories for COTS technologies  

SciTech Connect

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

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

1997-03-01

9

Characterization of Radiation Hard Silicon Materials  

SciTech Connect

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.

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

2009-02-24

10

New component of hard X-rays in solar flares  

Microsoft Academic Search

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

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

1981-01-01

11

February 24, 2009 Radiation-Hardness of VCSEL/PIN  

E-print Network

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

Gan, K. K.

12

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

NASA Astrophysics Data System (ADS)

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.

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

13

Radiation Hardness Assurance (RHA) for Space Systems  

NASA Technical Reports Server (NTRS)

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.

Poivey, Christian; Buchner, Stephen

2007-01-01

14

Fault-Tolerant, Radiation-Hard DSP  

NASA Technical Reports Server (NTRS)

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.

Czajkowski, David

2011-01-01

15

Component mixers and a hardness result for counterfeiting quantum money  

E-print Network

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.

Andrew Lutomirski

2011-07-01

16

Component mixers and a hardness result for counterfeiting quantum money  

E-print Network

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.

Lutomirski, Andrew

2011-01-01

17

Radiation Hard AlGaN Detectors and Imager  

SciTech Connect

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.

None

2012-05-01

18

High efficiency, radiation-hard solar cells  

SciTech Connect

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.

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

2004-10-22

19

1500 Gate standard cell compatible radiation hard gate array  

Microsoft Academic Search

The G1500 gate array combines Sandia Labs' 4\\/3..mu.. CMOS silicon gate radiation hard process with a novel gate isolated standard cell compatible design for quick turnaround time, low cost, and radiation hardness. This device is hard to 5 x 10⁵ rads, utilizes a configuration that provides high packing density, and is supported on both the Daisy and Mentor workstations. This

B. D. Mills; B. D. Shafer; E. P. Melancon

1984-01-01

20

Geometric optimization for radiation hardness assurance  

NASA Astrophysics Data System (ADS)

The probability of a single event effect occurring is generally a function of the energy deposited in a sensitive volume, which is typically expressed as the absorbed dose in that volume. For short segments of high energy particle tracks, the dose due to a single event is proportional to the chord length through the sensitive volume. Thus, the distribution of dose in chord length is likely to relate to the probability of single event effects. For various geometries, a differential chord length distribution was generated and from this the dose distribution, frequency mean chord length, and dose mean chord length were calculated. In every case, the dose mean chord length was greater than the frequency mean chord length by a minimum of 26% and increased with the eccentricity of the volume. The large value of the dose mean chord length relative to the frequency mean chord length demonstrates the need to consider rare, long-chord-length crossings in radiation hardness testing, despite their relatively low probability of occurrence.

Northum, J.; Guetersloh, S.

21

Implementing QML for radiation hardness assurance  

NASA Astrophysics Data System (ADS)

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 manufacture of 400-k-ohm feedback resistors required to provide SEU tolerance do not conform to 6 sigma quality standards. For total-dose, interface trap charge, Delta Vit, shifts measured on transistors are correlated with circuit response in the space environment. Statistical process control (SPC) is illustrated for Delta Vit, and violations of SPC rules are interpreted in terms of continuous improvement. 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, 3-D device-plus-circuit codes, and improved design simulators.

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

1990-12-01

22

Method for producing hard-surfaced tools and machine components  

DOEpatents

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.

McHargue, Carl J. (Farragut, TN)

1985-01-01

23

Method for producing hard-surfaced tools and machine components  

DOEpatents

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.

McHargue, C.J.

1981-10-21

24

New X-ray lasers schemes - Toward the hard radiation  

Microsoft Academic Search

Possibilities for creating an active medium for hard X-ray lasers using superbright (intensity in excess of 10 exp 17 W\\/sq cm) laser radiation pumping are examined. Several possible X-ray laser schemes are evaluated, and their advantages and disadvantages discussed. It is shown that an inner ionization type scheme is particularly promising for the realization of hard X-ray lasers.

V. V. Korobkin; M. Yu. Romanovskij

1992-01-01

25

Golden Rule of Radiation Hardness: a Study of Strain Effect on Controlled Radiation Damage  

NASA Astrophysics Data System (ADS)

Stain is widely presented in microstructures. Strain effect to radiation hardness is critical in understanding and engineering nano-materials. Here we studied the strain effect on the controlled radiation damage in monolayer hexagonal boron nitride (h-BN) through ab initio density functional theory calculations. We observed a general behavior of reduction in the radiation hardness by the strain, for both B-vacancy and N-vacancy configurations, in both compressive and tensive strain states, at the directions of zigzag, armchair and bi-axial. We proposed a golden rule of the radiation hardness states that any effort adding energy to the system will reduce the radiation hardness. Such golden rule of radiation hardness could be widely applied to material design and engineering for those devices working in irradiation-enrich environments, for example, electronic and optoelectronic devices in outer space.

Peng, Qing; Ji, Wei; de, Suvranu

2012-02-01

26

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

Microsoft Academic Search

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

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

1998-01-01

27

Electromagnetic Radiation Hardness of Diamond Detectors  

E-print Network

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

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

2001-08-22

28

Electromagnetic Radiation Hardness of Diamond Detectors  

E-print Network

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

Behnke, T; Ghodbane, N; Imhof, A; Martínez, C; Zeuner, W

2002-01-01

29

Curve Fitting Solar Cell Degradation Due to Hard Particle Radiation  

NASA Technical Reports Server (NTRS)

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.

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

2003-01-01

30

Solar cell nanotechnology for improved efficiency and radiation hardness  

Microsoft Academic Search

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

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

2006-01-01

31

R&D proposal for a fast and radiation hard crystal calorimeter at LHC  

E-print Network

Homogeneous crystal calorimeters are so far the best in terms of energy resolution and compactness. Large scale detectors have been built for several experiments and the engineering problems are well understood. One of these crystals, BaF2, is already well known as a fast and radiation hard scintillator. From our systematic studies of scintillation properties and radiation damage mechanisms of several scintillators, we believe that a complete family of fluorides crystals or glasses should behave like BaF2, but with a shorter radiation length and no slow component. The purpose of this R&D program is to study these materials in order to design a fast, compact, precise and radiation hard electromagnetic calorimeter for the LHC.

Lecoq, P

1990-01-01

32

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

E-print Network

for ultra-radiation hard semiconductor detectors for the inner tracker regions in high energy physicsComparing radiation tolerant materials and devices for ultra rad-hard tracking detectors Mara radiation hard than float zone silicon or with special detector structures with improved radiation

California at Santa Cruz, University of

33

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

PubMed

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. PMID:24880371

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

2014-05-01

34

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

35

Hard X-Ray Radiation in the Coma Cluster Spectrum  

NASA Astrophysics Data System (ADS)

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

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

1999-03-01

36

Neutron radiation hardness tests of SiPMs  

NASA Astrophysics Data System (ADS)

Hall D at Jefferson Laboratory is building its new GlueX spectrometer to study QCD gluonic excitations. The hermetic detector includes a scintillating fiber-lead barrel calorimeter where the photodetectors must operate in a high magnetic field. The silicon photomultiplier (SiPM) array manufactured by Hamamatsu Corporation was chosen for the photodetector of the BCAL. We report on the measurement of neutron radiation hardness of SiPMs at Jefferson Lab.

Qiang, Yi; Zorn, Carl; Barbosa, Fernando; Smith, Elton

2013-10-01

37

Development of a radiation-hard CMOS process  

NASA Technical Reports Server (NTRS)

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.

Power, W. L.

1983-01-01

38

Radiation-hard electrical coil and method for its fabrication  

DOEpatents

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.

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

1982-06-29

39

Hard X-ray Radiation in the Coma Cluster  

NASA Astrophysics Data System (ADS)

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

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

1998-12-01

40

Transient radiation hardness of the CMOSV 1. 25 micron technology  

SciTech Connect

Several devices fabricated in the AT and T/Sandia CMOSV 1.25 {mu}m technology have been characterized for transient radiation hardness. Dose rates upset levels exceeding 10{sup 9} rad (Si)/s were obtained on 16-bit microprocessor, 64K SRAM and 256K SRAM ICs. In this paper experimental data on neutron irradiated parts is given. Secondary photocurrents are shown to exist in logic structures which do not have adequate p-well contact placement. Layout guidelines are developed which allow the IC designer to eliminate secondary photocurrents in a given design.

Wunsch, T.F.; Hash, G.L.; Hewlett, F.W.; Treece, R.K. (Sandia National Labs., Albuquerque, NM (United States))

1991-12-01

41

Beetle—a radiation hard readout chip for the LHCb experiment  

NASA Astrophysics Data System (ADS)

A new radiation hard pipelined readout chip is being developed for the LHCb-experiment. Appropriate design measures have been taken to ensure the radiation hardness against total ionising dose effects in excess of 45 Mrad, as well as radiation effects induced by single particles.

Agari, M.; van Bakel, N.; Bauer, C.; Baumeister, D.; van Beuzekom, M.; Feuerstack-Raible, M.; Harnew, N.; Hofmann, W.; Jans, E.; Klous, S.; Knöpfle, K. T.; Löchner, S.; Schmelling, M.; Sexauer, E.; Smale, N.; Trunk, U.; Verkooijen, H.

2004-02-01

42

Strategies for Radiation Hardness Testing of Power Semiconductor Devices  

NASA Technical Reports Server (NTRS)

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.

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

43

Nanostructuring induced enhancement of radiation hardness in GaN epilayers  

SciTech Connect

The radiation hardness of as-grown and electrochemically nanostructured GaN epilayers against heavy ion irradiation was studied by means of photoluminescence (PL) and resonant Raman scattering (RRS) spectroscopy. A nanostructuring induced enhancement of the GaN radiation hardness by more than one order of magnitude was derived from the PL and RRS analyses. These findings show that electrochemical nanostructuring of GaN layers is a potentially attractive technology for the development of radiation hard devices.

Ursaki, V. V.; Tiginyanu, I. M.; Volciuc, O.; Popa, V.; Skuratov, V. A.; Morkoc, H. [Laboratory of Low-Dimensional Semiconductor Structures, Institute of Applied Physics, Academy of Sciences of Moldova, Chisinau 2028 (Moldova, Republic of) and National Center for Materials Study and Testing, Technical University of Moldova, Chisinau 2004 (Moldova); Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, 141980 Dubna, Moscow region (Russian Federation); Department of Electrical and Computer Engineering, Virginia Commonwealth University, Richmond, Virginia 23284 and Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284 (United States)

2007-04-16

44

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

SciTech Connect

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

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

2011-08-15

45

Integrating analog-to-digital converter radiation hardness test technique and results  

Microsoft Academic Search

The integrating ADC CMOS IC radiation hardness tests were performed. Dose rate, total dose and structural damage test techniques and results are presented and analyzed. It was found that low radiation hardness is inherent to an integrating ADC due to its operation principles

O. A. Kalashnikov; A. A. Demidov; V. S. Figurov; A. Y. Nikiforov; S. A. Polevich; V. A. Telets; S. A. Maljudin; A. S. Artamonov

1998-01-01

46

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

E-print Network

ELECTROMECHANICAL, THERMAL PROPERTIES AND RADIATION HARDNESS TESTS OF PIEZOELECTRIC ACTUATORS a dedicated facility located at CERI institute (Orléans, France) for radiation hardness tests of actuators a decrease of the maximum displacement X of the actuators tested from X ~40µm @ 300K down to 1.8µm-3.5 µm @ 1

Paris-Sud XI, Université de

47

Gas-chromatographic determination of the main components of hard-coal tar and its fractions  

SciTech Connect

The component compositions of the hard-coal pitches from a number of coke and chemicals factories of the UkrSSR have been investigated with the aid of gasliquid chromatography. It has been shown that the results of analysis can be used for the operative control of the quality of the fractions obtained.

Nabivach, V.M.; Berlizov, Yu.S.; Chernyshov, Yu.A.; Gerasimenko, V.A.; Gribanova, T.I.; Grumbery, L.R.; Ryabozad, A.S.; Shvarts, S.G.; Voitenko, B.I.

1983-01-01

48

Fault tolerant, radiation hard, high performance digital signal processor  

NASA Technical Reports Server (NTRS)

An architecture has been developed for a high-performance VLSI digital signal processor that is highly reliable, fault-tolerant, and radiation-hard. The signal processor, part of a spacecraft receiver designed to support uplink radio science experiments at the outer planets, organizes the connections between redundant arithmetic resources, register files, and memory through a shuffle exchange communication network. The configuration of the network and the state of the processor resources are all under microprogram control, which both maps the resources according to algorithmic needs and reconfigures the processing should a failure occur. In addition, the microprogram is reloadable through the uplink to accommodate changes in the science objectives throughout the course of the mission. The processor will be implemented with silicon compiler tools, and its design will be verified through silicon compilation simulation at all levels from the resources to full functionality. By blending reconfiguration with redundancy the processor implementation is fault-tolerant and reliable, and possesses the long expected lifetime needed for a spacecraft mission to the outer planets.

Holmann, Edgar; Linscott, Ivan R.; Maurer, Michael J.; Tyler, G. L.; Libby, Vibeke

1990-01-01

49

Radiation-hard/high-speed parallel optical engine  

NASA Astrophysics Data System (ADS)

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.

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

2012-12-01

50

Comptonization of low-frequency radiation in accretion disks Angular distribution and polarization of hard X-ray radiation  

SciTech Connect

Analytical consideration is given to the comptonization of photons and its effects on the radiation emitted from accretion disks of compact X-ray sources, such as black holes and neutron stars. Attention is given to the photon distribution during escape from the disk, the angular distribution of hard radiation from the disk, the polarization of hard radiation and the electron temperature distribution over the optical depth. It is shown that the hard radiation spectrum is independent of the low-frequency photon source distribution. The angular distribution and polarization of the outgoing X-rays are a function of the optical depth. A Thomson approximation is used to estimate the angular distribution of the hard radiation and the polarization over the disk. The polarization results are compared with OSO-8 satellite data for Cyg X-1 and show good agreement at several energy levels. 17 references.

Suniaev, R.A.; Titarchuk, L.G.

1984-01-01

51

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

NASA Astrophysics Data System (ADS)

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

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

1995-10-01

52

GaAs ICs for new defense systems offer speed and radiation hardness benefits  

NASA Astrophysics Data System (ADS)

In connection with rapid technical growth affecting the world of electronic warfare (EW), it will be necessary to design both electronic support measure and electronic countermeasure systems with improved algorithms and processing techniques. The designs will have to be implemented with higher speed electronic components. It is pointed out that the performance advantages of GaAs integrated circuits, particularly in the area of speed, make this technology the prime candidate for satisfying next generation wideband signal and data processing system requirements. GaAs digital integrated circuits offer advantages in speed, power dissipation, radiation hardness, and operating temperature range. Activities to reduce electron transit time for the improvement of device speed are focused on second generation GaAs devices referred to as heterostructures, since they consist of two different material systems, GaAs and AlGaAs. New developments related to the use of GaAs ICs are reviewed.

Firstenberg, A.; Rooslid, S.

1985-03-01

53

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

E-print Network

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

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

2009-12-22

54

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

NASA Technical Reports Server (NTRS)

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.

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

1985-01-01

55

Evaluation of the Timepix chip radiation hardness using a 60Co source  

NASA Astrophysics Data System (ADS)

Radiation damage is a widely studied topic for its effects on detectors and supporting electronics in various practical applications. Radiation hardness and stability of the detector properties are critical parameters in applications of semiconductor radiation detectors. The 0.25 ?m CMOS technology used in fabrication of the Medipix2 and Timepix chips provides high degree of inherent radiation hardness. We present the study of operational, detection and signal processing properties of the irradiated Timepix chip exposed to a high-flux 60Co source reaching the operational limits of the chip.

?arná, Mária; Du?evová, Kate?ina; Hejtmánek, Martin; Kon?ek, Ond?ej; Mar?išovský, Michal

2013-12-01

56

The soft X-ray component and the hard continuum curvature in black hole binaries  

NASA Astrophysics Data System (ADS)

We propose a 40ksec joint XMM-Newton/NuSTAR observation of the black hole binary Swift J1753.5-0127 in its persistent faint low/hard state. This will constrain the radial stratification of the corona and the spectral curvature of the low/hard state continuum in the unprecedented 0.7-70keV band. This will then give the most unambigious measure of the strength of the soft X-ray component and resolve some of the controversies over the accretion geometry. The observation will also help with ongoing calibration/cross- calibration efforts for both satellites. This observation is not time critical, and will be feasible when it best suits the satellites' schedules. An ongoing AMI LA radio monitoring programme of Swift J1753.5-0127 will be adapted to coincide with this XMM-Newton/NuSTAR observation.

Kolehmainen, Mari

2013-10-01

57

Effect Of Clock Mode On Radiation Hardness Of An ADC  

NASA Technical Reports Server (NTRS)

Report discusses techniques for testing and evaluating effects of total dosages of ionizing radiation on performances of high-resolution successive-approximation analog-to-digital converters (ADCs), without having to test each individual bit or transition. Reduces cost of testing by reducing tests to few critical parametric measurements, from which one determines approximate radiation failure levels providing good approximations of responses of converters for purpose of total-dose-radiation evaluations.

Lee, Choon I.; Rax, Bernie G.; Johnston, Allan H.

1995-01-01

58

Optimum laboratory radiation source for hardness assurance testing  

Microsoft Academic Search

Silicon-on-insulator (SOI) and bulk-silicon transistors were irradiated using X-ray, Co-60 gamma, and proton radiation sources. Co-60 gamma irradiation generates larger radiation-induced threshold voltage shifts (by a factor of two) in SOI buried oxides and in parasitic field oxides under low-field conditions than X-ray or proton irradiation. For all devices examined, the radiation-induced threshold voltage shifts generated by X-ray irradiation were

J. R. Schwank; M. R. Shaneyfelt; P. Paillet; D. E. Beutler; V. Ferlet-Cavrois; B. L. Draper; R. A. Loemaker; P. E. Dodd; F. W. Sexton

2001-01-01

59

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

E-print Network

Transition radiation in metal-metal multilayer nanostructures as a medical source of hard x at developing an x-ray source for medical applications, which is based on using low-energy relativistic in mind, we have considered also the unwanted effects due to bremsstrahlung radiation, absorption

Kaplan, Alexander

60

Results of radiation hardness tests and performance tests of the HS9008RH flash ADC  

Microsoft Academic Search

Results from tests characterizing the performance and radiation hardness of the HS9008RH flash analog to digital convertor (FADC) are presented. These tests were performed primarily to evaluate the suitability of this device for use in the GEM Central Tracker at the SSC experiment. Basic performance characteristics and susceptibility of these characteristics to radiation were examined. Performance test results indicate that

S. Nutter; G. Tarle; H. B. Crawley; R. McKay; W. T. Meyer; E. I. Rosenberg; W. D. Thomas

1994-01-01

61

Radiation-hardness testing of electronic devices: A study of facility dosimetry practices  

Microsoft Academic Search

As part of a program to develop better quality assurance in the measurement of total dose in the field of radiation-hardness testing of electronic devices, a survey was conducted at twelve radiation test facilities. The survey was carried out through personal visits during which various characteristics of the test facilities and dosimetry procedures were noted. This report summarizes the results

J. C. Humphreys; S. E. Chappell

1976-01-01

62

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

SciTech Connect

This report describes the research accomplishments achieved under the LDRD Project 'Radiation Hardened Optoelectronic Components for Space-Based Applications.' The aim of this LDRD has been to investigate the radiation hardness of vertical-cavity surface-emitting lasers (VCSELs) and photodiodes by looking at both the effects of total dose and of single-event upsets on the electrical and optical characteristics of VCSELs and photodiodes. These investigations were intended to provide guidance for the eventual integration of radiation hardened VCSELs and photodiodes with rad-hard driver and receiver electronics from an external vendor for space applications. During this one-year project, we have fabricated GaAs-based VCSELs and photodiodes, investigated ionization-induced transient effects due to high-energy protons, and measured the degradation of performance from both high-energy protons and neutrons.

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

2003-12-01

63

Radiation hardness of Si strip detectors with integrated coupling capacitors  

Microsoft Academic Search

Si strip detectors with integrated coupling capacitors between diode and metallization and with separate bias resistors for each strip have been exposed to ionising radiation. Results from measurements of detector response before and after irradiation are presented.

H. Dijkstra; R. Horisberger; L. Hubbeling; G. Maehlum; A. Peisert; P. Weilhammer; T. Tuuva; L. Evensen

1989-01-01

64

Mapping daily and monthly radiation components using METEOSAT data  

Microsoft Academic Search

The aim of the study is to present actual daily and climatically representative monthly maps of the surface radiation balance components derived from METEOSAT data. The encrypted digital images are now available in every three hours in Hungary. Hence, the first problem to solve is the estimation of diurnal mean radiation components from the archived 1–3 observations of the day

A. Rimóczi-Paál; J. Kerényi; J. Mika; R. Randriamampianina; I. Dobi; Z. Imecs; T. Szentimrey

1999-01-01

65

Total dose hardness assurance testing using laboratory radiation sources  

Microsoft Academic Search

NMOS transistors were irradiated using X-ray, Co-60 gamma, electron, and proton radiation sources. The charge yield was estimated for protons of different energies and electrons, and compared with values obtained for X-ray and Co-60 irradiations.

P. Paillet; J. R. Schwank; M. R. Shaneyfelt; V. Ferlet-Cavrois; R. L. Jones; O. Flament; E. W. Blackmore

2003-01-01

66

FPIX2: A radiation-hard pixel readout chip for BTeV  

SciTech Connect

A radiation-hard pixel readout chip, FPIX2, is being developed at Fermilab for the recently approved BTeV experiment. Although designed for BTeV, this chip should also be appropriate for use by CDF and DZero. A short review of this development effort is presented. Particular attention is given to the circuit redesign which was made necessary by the decision to implement FPIX2 using a standard deep-submicron CMOS process rather than an explicitly radiation-hard CMOS technology, as originally planned. The results of initial tests of prototype 0.25{micro} CMOS devices are presented, as are plans for the balance of the development effort.

David C. Christian et al.

2000-12-11

67

High-temperature, radiation-hard electronic technology  

NASA Astrophysics Data System (ADS)

We report on two novel high temperature and potentially highly neutron and gamma radiation resistant electronc technologies that are suitable for nuclear and space applications. The operational effects on these technologies from gamma radiation doses up to 10 megarads and 1-MeV equivalent neutron fluences up to 1014 neutrons/cm2 are examined using a calibrated (to appropriate ASTM standards) irradiation chamber in the University of Utah TRIGA Nuclear Reactor. The first high temperature, harsh environment technology is based on microminiature vacuum (MTV) devices. The second high temperature technology is gallium arsenide (GaAs) metal semiconductor field effect transistor (MESFET)-based devices and circuits that can operate at temperatures up to 350 °C. This MESFET-based technology also allows a wide range of control with respect to the MESFET's enhanced resistance to breakdown at elevated temperatures. The MESFET-based technology has general applicability and works equally well with both enhancement and depletion n-channel MESFET's.

Sadwick, Larry P.; Zhang, Jenny; Schaeffer, Donald; Petelenz, Danka; Crofts, Richard J.; Yao-Hsien Feng, Hwu, R. Jennifer; Sandquist, Gary M.; Slaughter, D. M.

1995-01-01

68

Linear polydiorganosiloxanes as plastic bases for radiation hard scintillators  

Microsoft Academic Search

Melt-processible (spinnable) polydiorganosiloxanes have been tested. The polymers offer advantages over previously explored thermosetting siloxane systems. Radiation damage to the optical properties of this polymer have been measured and are smaller than other known optical polymers. Most importantly, intramolecular proton transfer dyes (e.g. 3-Hydroxyflavone) exhibit large Stokes shifted fluorescence in the thermoplastic, unlike that in comparable thermosetting systems. A plastic

J. Harmon; J. Gaynor; V. Feygelman; J. Walker

1991-01-01

69

Axial ion-electron emission microscopy of IC radiation hardness  

NASA Astrophysics Data System (ADS)

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 stopping power for heavy ions is near a maximum at this velocity, and their range is ˜20 ?m in Si. These ions therefore represent the most ionizing form of radiation in nature, and are nearly ideal for performing single event effects testing of integrated circuits. Unfortunately, the energy definition of the RFQ-boosted ions is rather poor (˜ a few %), which makes problematic the focussing of such ions to the submicron spots required for REM. To circumvent this problem, we have invented ion electron emission microscopy (IEEM). One can perform REM with the IEEM system without focussing or scanning the ion beam. This is because the position on the sample where each ion strikes is determined by projecting ion-induced secondary electrons at high magnification onto a single electron position sensitive detector. This position signal is then correlated with each REM event. The IEEM system is now mounted along the beam line in an axial geometry so that the ions pass right through the electron detector (which is annular), and all of the electrostatic lenses used for projection. The beam then strikes the sample at normal incidence which results in maximum ion penetration and removes a parallax problem experienced in an earlier system. Details of both the RFQ-booster and the new axial IEEM system are given together with some of the initial results of performing REM on Sandia-manufactured radiation hardened integrated circuits.

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

2002-05-01

70

Radiation Hardness and Linearity Studies of CVD Diamonds  

E-print Network

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

Behnke, T; Ghodbane, N; Imhof, A

2003-01-01

71

Radiation Hardness and Linearity Studies of CVD Diamonds  

E-print Network

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

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

2002-12-09

72

Chapter 10 Radiation effects in electronic components  

Microsoft Academic Search

A silicon device, operating in a radiation environment, and not designed or protected for that purpose will eventually fail. If we exclude dose rate effects, which are not treated in this chapter, there exist two basic failure modes: one due to displacement damage, the other one due to ionizing dose effect.When an energetic particle penetrates inside a material it generates

D. Bräunig; F. Wulf

1999-01-01

73

Radiation induced modification in nanoscale hardness of ZnO cone structures  

NASA Astrophysics Data System (ADS)

In this paper, the effect of ion irradiation on nanoscale hardness of ZnO microcones is reported. The hardness of ZnO cones determined by nanoindentation using atomic force microscope initially increases from 4.7±1.4 to 9.5±1.6 GPa after irradiation with 1.2 MeV Ar+8 ions at an ion fluence of 1015 ions cm-2 and then decreases with increasing ion fluence. This change in mechanical hardness has been correlated with the residual stress of the sample revealed by Raman peak shift in the E2(H) mode. These results show that the generally reported radiation-hard nature of ZnO depends critically on irradiation conditions, especially the irradiation temperature.

Nagar, Rupali; Teki, R.; Koratkar, N.; Sathe, V. G.; Kanjilal, D.; Mehta, B. R.; Singh, J. P.

2010-09-01

74

X-ray silicon detectors for measuring hard x-ray radiation damage effects  

Microsoft Academic Search

For high sensitivity hard x-ray detector applications there is a solid-state alternative using high purity silicon as starting material. The paper presents some original results concerning a radiation hardened technology to be used for obtaining x-ray silicon detectors and the behavior of the special designed devices in a specific radiation environment. Original processing sequences were experimentally tested and results concerning

Delia Wagner; Eugenia T. Halmagean; Dido Y. Loukas; K. Misiakos; Elisabeth Tsoi; A. Veron; M. Ohanisian

1997-01-01

75

Radiation hardness tests of scintillating tile\\/WLS fiber calorimeter modules  

Microsoft Academic Search

The radiation hardness properties of a tile\\/fiber calorimeter with different materials or with different optical path layouts have been studied. Ten calorimeter modules of a geometry similar to that of the proposed SDC calorimeter were irradiated using the BEPC electron beam (1.1 or 1.3 GeV). Radiation damage was quantified by measuring the light yield at various locations within the calorimeter

S. W. Han; L. D. Hu; N. Z. Liu; H. S. Mao; H. Z. Shi; Y. P. Tan; G. L. Wang; C. D. Zhang; G. Zhang; L. S. Zhang; Z. X. Zhang; X. J. Zhao; L. S. Zheng; X. C. Zhong; Y. S. Zhou; A. Byon-Wagner; D. Green; A. Para; K. Johnson; V. Barnes

1995-01-01

76

Hard-x-ray radiation from short-pulse laser-produced plasmas  

Microsoft Academic Search

The generation of hard-x-ray radiation (???25 keV) from short-pulse Ti:sapphire laser-produced plasmas is studied. Solid targets are irradiated by 0.2–10 ps laser pulses in the intensity range of 5×1013?5×1016 W\\/cm2. It is shown that the measured dose rates obey a simple scaling law.

Boris N. Chichkov; Carsten Momma; Andreas Tünnermann; Susanne Meyer; Thomas Menzel; Bernd Wellegehausen

1996-01-01

77

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

E-print Network

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.

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

78

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

PubMed

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

Belaldavar, C; Hallikerimath, S; Angadi, Pv; Kale, Ad

2014-11-01

79

10th International Conference on Large Scale Applications and Radiation Hardness of Semiconductor Detectors  

NASA Astrophysics Data System (ADS)

The primary goal of the Conference is to review the present status of the Semiconductor Detector apparatuses in the field of High Energy or Astroparticle Physics. In both cases the requests on the detector systems are very demanding: very large instrumented surface, radiation hardness and high reliability. During the conference a large part of the talks will be devoted to describe the pixel and microstrip silicon-based detectors operated in the LHC experiments (Alice, Atlas, CMS, LHCb). The operational experience and the detector performance with the p-p runs 2010-2011 will be discussed. A fraction of the talks will describe possible LHC luminosity upgrade (HL-LHC) and recent developments on detector radiation hardness. The astroparticle detectors activity will also be reviewed. Topics related to the development and applications of detector electronics will be presented too. Finally semiconductor applications in different fields, like medical Dosimetry and Photomultipliers will be rapidly touched.

80

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

Microsoft Academic Search

The electromagnetic calorimeter of PANDA at the FAIR facility will rely on the operation of lead tungstate (PbWO4, PWO) scintillating crystals at temperatures near -25?C to provide sufficient resolution for photons in the energy range from 8GeV down to 10MeV. The radiation hardness of PWO crystals was studied at the IHEP (Protvino) irradiation facility in the temperature range from +20?C

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

2007-01-01

81

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

Microsoft Academic Search

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

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

1997-01-01

82

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

Microsoft Academic Search

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

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

83

Radiation hardness test of FSSR, a multichannel, mixed signal chip for microstrip detector readout  

Microsoft Academic Search

The Fermilab Silicon Strip Readout (FSSR) chip is a 128-channel, mixed signal circuit, which was designed for processing the signals from the microstrip detectors of the BTeV experiment at the Tevatron collider. The design was carried out in a 0.25 mum CMOS technology, whose intrinsic radiation hardness is supposed to satisfy the application requirements. Such features were further improved by

Lodovico Ratti; Massimo Manghisoni; V. Re; G. Traversi; A. Candelori

2005-01-01

84

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

NASA Astrophysics Data System (ADS)

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

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

2013-09-01

85

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

EU contract number RII3-CT-2003-506395 CARE-Note-07-004-SRF SRF Radiation hardness tests was developed at IPN Orsay and used previously for radiation hardness test of calibrated cryogenic thermometers operated for radiation hardness tests of several piezoelectric actuators at T~4.2 K. This new apparatus

Paris-Sud XI, Université de

86

APPLICATION SPECIFIC RADIATION TESTS FOR COTS EEE COMPONENTS  

Microsoft Academic Search

To assess the suitability of epoxy-encapsulated COTS EEE components for space appli- cations, a suite of new radiation test procedures for parts selection and up-screening were developed at the Technical University of Denmark (DTU). For Total Ionising Dose (TID) tests the electron emitter Sr-90\\/Y-90 is used instead of conventional gamma emit- ters like Co-60. The easily shielded electron radiation allows

Gøsta Thuesen; Peter Buch Guldager; John Leif Jørgensen

87

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

E-print Network

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...

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

2014-01-01

88

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

NASA Astrophysics Data System (ADS)

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

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

2003-09-01

89

SOLAR RADIATION DURABILITY OF MATERIALS, COMPONENTS AND SYSTEMS FOR PHOTOVOLTAICS  

E-print Network

SOLAR RADIATION DURABILITY OF MATERIALS, COMPONENTS AND SYSTEMS FOR PHOTOVOLTAICS Myles P. Murray 1 exposed photovoltaic materials, is defined as the rate of photodarkening or photobleaching of a material testing. The potential to predict power losses in a photovoltaic system over time caused

Rollins, Andrew M.

90

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

SciTech Connect

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

Yi Qiang, Carl Zorn, Fernando Barbosa, Elton Smith

2013-01-01

91

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

E-print Network

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.

Yi Qiang; Carl Zorn; Fernando Barbosa; Elton Smith

2012-07-16

92

Radiation mitigating properties of the lignan component in flaxseed  

PubMed Central

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

2013-01-01

93

Radiation Specifications for Fission Power Conversion Component Materials  

NASA Technical Reports Server (NTRS)

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

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

2011-01-01

94

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

NASA Astrophysics Data System (ADS)

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

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

2010-11-01

95

Radiation hardness of a silicon MESFET 4K x 1 sRAM  

SciTech Connect

A comprehensive study of the radiation hardness of the silicon MESFET technology using LOCOS isolation is reported. A MESFET 4K x 1 sRAM fabricated on bulk silicon using LOCOS isolation has essentially no change in performance through 28.5 Mrad(Si) total gamma dose, the maximum dose tested. Transient gamma upset of the memory occurs at 1 x 10/sup 7/ Rad(Si)/s. Discrete MESFET and LOCOS device characteristics are also reported as a function of total gamma dose.

Houston, T.W.; Darley, H.M.; Hite, L.R.; Lapierre, D.C.; Shedd, W.M.; Zugich, M.H.

1984-12-01

96

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

E-print Network

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

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

2010-02-18

97

Total dose radiation hard 0.35 {micro}m SOI CMOS technology  

SciTech Connect

This paper presents the total dose radiation performance of 0.35 {micro}m SOI CMOS devices fabricated in a radiation hard full dose SIMOX technology. The radiation performance is characterized by transistor threshold voltage shifts, transistor array leakage currents, and 256K SRAM standby currents as a function of total dose up to 190 Mrad (SiO{sub 2}). The worst case threshold voltage shifts of front channels are less than 60 mV for PMOS transistors /at 1 Mrad(SiO{sub 2}) and less than 10 mV for NMOS transistors. No significant radiation induced leakage currents are observed in small transistor arrays to 10 Mrad(SiO{sub 2}). Standby currents of 256K SRAMs are less than the 1.5 mA specification over the total dose range of 1 Mrad(SiO{sub 2}). The results suggest high density SRAMs and ASIC fabricated in this technology will perform well in harsh radiation environment.

Liu, S.T. [Honeywell Solid State Electronics Center, Plymouth, MN (United States)] [Honeywell Solid State Electronics Center, Plymouth, MN (United States); Jenkins, W.C.; Hughes, H.L. [Naval Research Lab., Washington, DC (United States)] [Naval Research Lab., Washington, DC (United States)

1998-12-01

98

Development of radiation hard semiconductor sensors for charged particle tracking at very high luminosities  

NASA Astrophysics Data System (ADS)

The RD50 collaboration (sponsored by the European Organization for Nuclear Research CERN) has been exploring the development of radiation hard semiconductor devices for very high-luminosity colliders since 2002. The target fluence to qualify detectors set by the anticipated dose for the innermost tracking layers of the future upgrade of the CERN large hadron collider (LHC) is 1016 1 MeV neutron equivalent (neq) cm-2. This is much larger than typical fluences in space, but is mainly limited to displacement and total dose damage, without the single-event effects typical for the space environment. RD50 investigates radiation hardening from many angles, including: Search for alternative semiconductor to replace silicon, improvement of the intrinsic tolerance of the substrate material (p- vs. n-type, initial doping concentration, oxygen concentration), optimization of the readout geometry (collection of holes or electrons, surface treatment), novel detector designs (3D, edge-less, interconnects).

Betancourt, Christopher; Fadeyev, Vitaliy; Sadrozinski, Hartmut F.; Wright, John

2010-09-01

99

A PCI Express optical link based on low-cost transceivers qualified for radiation hardness  

NASA Astrophysics Data System (ADS)

In this paper we want to demonstrate that an optical physical medium is compatible with the second generation of PCI Express. The benefit introduced by the optical decoupling of a PCI Express endpoint is twofold: it allows for a geographical detachment of the device and it remains compliant with the usual PCI accesses to the legacy I/O and memory spaces. We propose two boards that can bridge the PCI Express protocol over optical fiber. The first is a simple optical translator while the second is a more robust switch developed for connecting up to four devices to a single host. Such adapters are already working in the control and data acquisition system of a particle detector at CERN and hence they had been qualified for radiation hardness. The positive outcomes of the radiation tests of four types of off-the-shelf transceivers are finally reported.

Triossi, A.; Barrientos, D.; Bellato, M.; Bortolato, D.; Isocrate, R.; Rampazzo, G.; Ventura, S.

2013-02-01

100

Radiation-hardness testing of electronic devices: a survey of facility dosimetry practices. Final report Jan--Sep 1976  

Microsoft Academic Search

As part of a program to develop better quality assurance in the measurement of total dose in the field of radiation-hardness testing of electronic devices, a survey was conducted at twelve radiation test facilities. The survey was carried out through personal visits during which various characteristics of the test facilities and dosimetry procedures were noted. This report summarizes the results

J. C. Humphreys; S. E. Chappell

1976-01-01

101

Radiation accident dosimetry on electronic components by OSL.  

PubMed

In the event of large-scale radiation accidents and considering a growing terrorism concern, non-invasive and sufficiently accurate retrospective dosimetry methods are necessary to carry out a fast population triage in order to determine which radiation-exposed individuals need medical treatment. Retrospective dosimetry using different electronic components such as resistors, capacitors, and integrated circuits present on mobile phone circuit boards have been considered. Their response has been investigated with luminescence techniques (OSL, IRSL, and TL). The majority of these electronic components exhibit radiation-induced luminescence signals, and the OSL technique seems the most promising for these materials. Results concerning three types of components that present the most interesting OSL characteristics (in terms of signal annealing and sensitivity) and that are the most often present on mobile phone circuit boards are presented. Preheating effects on OSL signal, sensitization, and dose-response curves from 0.7 to 27 Gy for resistors and from 0.7 to 160 Gy for capacitors and integrated circuits, dose recovery tests, and signal stability 10 h after irradiation have been studied and interests and limits of their use evaluated. PMID:20065718

Bassinet, C; Trompier, F; Clairand, I

2010-02-01

102

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

NASA Astrophysics Data System (ADS)

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

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

1999-08-01

103

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

Microsoft Academic Search

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.

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

2006-01-01

104

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

SciTech Connect

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

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

2013-06-10

105

A 0.13$\\mu$m CMOS technology Its radiation hardness and its application in high energy physics experiments  

E-print Network

Radiation hardness is a major concern for electronics in high luminosity colliders for high energy physics (HEP). For several years, the HEP community has studied and evaluated radiation hard technologies suitable for the development of analog, digital, and mixed signal application specific integrated circuits. The European Organization for Nuclear Research (CERN) uses currently extensively a commercial 0.25?m complementary metal oxide semiconductor (CMOS) technology for the custom-developed integrated circuits for instrumentation in the Large Hadron Collider. This technology has been carefully evaluated in the past and several measures have been taken to assert the radiation hardness of its applications. To explore the benefits of more advanced technologies, to stay in line with technology progress and in order to prepare for a phase out of this quarter micron technology, a 0.13?m CMOS technology has been analyzed. This thesis outlines, after a theoretical introduction into the fields of ra...

Hänsler, Kurt

2004-01-01

106

First radiation hardness results of the TeraPixel Active Calorimeter (TPAC) sensor  

NASA Astrophysics Data System (ADS)

The TeraPixel Active Calorimeter (TPAC) sensor is a novel Monolithic Active Pixel Sensors (MAPS) device developed for use as the active layers of a large area, digital electromagnetic calorimeter (DECAL) at a future e+e- collider. Further applications, which include the tracking and vertex systems for future lepton colliders and LHC upgrades have been proposed and it is therefore essential to characterise the behaviour of the sensor for these applications. We present the first studies of radiation hardness testing of the TPAC sensor. The performance of the sensor has been evaluated after exposures up to 5 Mrad of 50 keV x-rays. Under realistic ILC operating conditions a maximum decrease in the signal to noise ratio of 8% (15%) was observed after 200 krad (5 Mrad) which is already sufficient for proposed applications in future e+e- colliders.

Price, T.; Watson, N.; Wilson, J.; Rajovic, V.; Cussans, D.; Goldstein, J.; Head, R.; Nash, S.; Page, R.; Velthuis, J.; Strube, J.; Stanitzki, M.; Dauncey, P.; Gao, R.; Nomerotski, A.; Coath, R.; Crooks, J.; Turchetta, R.; Tyndel, M.; Worm, S.; Zhang, Z.

2013-01-01

107

Holotomography: Quantitative phase tomography with micrometer resolution using hard synchrotron radiation x rays  

NASA Astrophysics Data System (ADS)

Because the refractive index for hard x rays is slightly different from unity, the optical phase of a beam is affected by transmission through an object. Phase images can be obtained with extreme instrumental simplicity by simple propagation provided the beam is coherent. But, unlike absorption, the phase is not simply related to image brightness. A holographic reconstruction procedure combining images taken at different distances from the specimen was developed. It results in quantitative phase mapping and, through association with three-dimensional reconstruction, in holotomography, the complete three-dimensional mapping of the density in a sample. This tool in the characterization of materials at the micrometer scale is uniquely suited to samples with low absorption contrast and radiation-sensitive systems.

Cloetens, P.; Ludwig, W.; Baruchel, J.; Van Dyck, D.; Van Landuyt, J.; Guigay, J. P.; Schlenker, M.

1999-11-01

108

Absorption of laser radiation by components of disperse layer  

NASA Astrophysics Data System (ADS)

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 of 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 method is proposed for estimation of quantity of absorbed energy and its deep distribution separately for each structure component of the layer, i.e. for particles and a bulk. The computational results are given for a layer with the following parameters: a mean size of light-scattering particles, d = 0.3 mcm; size distribution of particles is logarithmically normal one with polydispersity, Cv=20%; volume concentration of particles, Vc=5, 7.5, 10 and 15%; thickness of the layer, H=10 mcm. Computations were performed for wavelength ? = 442 nm.

Kozakov, Oleg N.

2004-06-01

109

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

NASA Astrophysics Data System (ADS)

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

Nguyen, Sandy Linhsa

110

Modeling of Radiation Hardness of a CCD with High-Speed Column Parallel Readout  

NASA Astrophysics Data System (ADS)

Charge Coupled Devices (CCDs) have been successfully used in several high energy physics experiments over the past two decades. Their high spatial resolution and thin sensitive layers make them an excellent tool for studying short-lived particles. The Linear Collider Flavour Identification (LCFI) collaboration is developing Column-Parallel CCDs (CPCCDs) for the vertex detector of a future Linear Collider. The CPCCDs can be read out many times faster than standard CCDs, significantly increasing their operating speed. Radiation hardness is an important aspect in the CCD development. Bulk radiation damage in the silicon leads to electron traps and hence to charge transfer inefficiency (CTI). The effects of the two trap levels 0.17 and 0.44 eV are considered. We have extended our Analytic Model to include the effects of the shape of the signal charge packet and the clock voltage on the CTI determination. The CTI values determined with the Analytic Model largely agree with those from a full TCAD simulation.

Sopczak, André; Aoulmit, Salim; Bekhouche, Khaled; Bowdery, Chris; Buttar, Craig; Damerell, Chris; Djendaoui, Dahmane; Dehimi, Lakhdar; Greenshaw, Tim; Koziel, Michal; Maneuski, Dzmitry; Nomerotski, Andrei; Stefanov, Konstantin; Tikkanen, Tuomo; Woolliscroft, Tim; Worm, Steve

2009-12-01

111

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

NASA Astrophysics Data System (ADS)

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.

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

112

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

NASA Astrophysics Data System (ADS)

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.

Baptista, Brian

113

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

NASA Technical Reports Server (NTRS)

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.

Lauenstein, Jean-Marie

2011-01-01

114

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

PubMed Central

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

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

2014-01-01

115

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

NASA Astrophysics Data System (ADS)

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.

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

2006-09-01

116

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

Microsoft Academic Search

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

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

2000-01-01

117

Radiation hard detectors from silicon enriched with both oxygen and thermal donors: improvements in donor removal and long-term stability with regard to neutron irradiation  

Microsoft Academic Search

Detectors made on the silicon wafers with high concentration of thermal donors (TD), which were introduced during the high temperature long time (HTLT) oxygenation procedure, have been investigated in the study of radiation hardness with regard to neutron irradiation and donor removal problems in irradiated high resistivity Si detectors. Two facts have been established as the evidence of radiation hardness

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

2002-01-01

118

Radiation-Hard SpaceWire/Gigabit Ethernet-Compatible Transponder  

NASA Technical Reports Server (NTRS)

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.

Katzman, Vladimir

2012-01-01

119

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

SciTech Connect

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.

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

1995-12-31

120

Demonstration of Boron Arsenide Heterojunctions: A Radiation Hard Wide Band Gap Semiconductor Device  

SciTech Connect

B{sub 12}As{sub 2}/SiC pn heterojunction diodes based on the radiation-hard B{sub 12}As{sub 2} deposited on (0001) n-type 4H-SiC via chemical vapor deposition were demonstrated. The diodes exhibit good rectifying behavior with an ideality factor of 1.8 and a leakage current as low as 9.4 x 10{sup -6} A/cm{sup 2}. Capacitance-voltage measurements using a two-frequency technique showed a hole concentration of - 1.8-2.0 x 10{sup 17} cm{sup -3} in B{sub 12}As{sub 2} with a slight increase near the interface due to the presence of an interfacial layer to accommodate lattice mismatch. Band offsets between the B{sub 12}As{sub 2} and SiC were estimated to be - 1.06 eV and 1.12 eV for conduction band and valance band, respectively.

Gong, Y.; Tapajna, M; Bakalova, S; Zhang, Y; Edgar, H; Zhang, Y; Dudley, M; Hopkins, M; Kuball, M

2010-01-01

121

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

NASA Technical Reports Server (NTRS)

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.

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

1995-01-01

122

Biochemical changes in blood components after lethal doses of radiation. Final report Oct 80-Sep 81  

SciTech Connect

Nonpeptide, peptide, and protein blood components were measured postirradiation in Wistar rats to investigate biochemical changes that might be related to or form the basis of radiation-induced emesis. The rats were irradiated with lethal doses of radiation, and blood components were analyzed at various times postirradiation. The blood-component levels were compared to those of nonirradiated controls to determine if any significant changes occurred due to the radiation.

Magro, A.M.

1982-10-01

123

Influence of growing and doping methods on radiation hardness of n-Si irradiated by fast-pile neutrons  

Microsoft Academic Search

Silicon n-type samples with resistivity ~2.5·103 Ohm·cm grown by the method of a floating-zone in vacuum (FZ), in argon atmosphere (Ar) and received by the method of trans- mutation doping (NTD) are investigated before and after irradiation by various doses of fast- pile neutrons at room temperature. The radiation hardness of n-type silicon is shown to be determined first of

A. P. Dolgolenko; P. G. Litovchenko; A. P. Litovchenko; M. D. Varentsov; V. F. Lastovetsky; G. P. Gaidar

124

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

NASA Technical Reports Server (NTRS)

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.

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

1991-01-01

125

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

DOEpatents

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

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

1999-01-01

126

A built-in SRAM for radiation hard CMOS pixel sensors dedicated to high energy physics experiments  

NASA Astrophysics Data System (ADS)

CMOS pixel sensors (CPS) are attractive candidates for charged particle tracking in high energy physics experiments. However, CPS chips fabricated with standard CMOS processes, especially the built-in SRAM IP cores, are not radiation hard enough for this application. This paper presents a radiation hard SRAM for improving the CPS radiation tolerance. The SRAM cell is hardened by increasing the static noise margin (SNM) and adding P+ guard rings in layout. The peripheral circuitry is designed by building a radiation-hardened logic library. The SRAM internal timing control is hardened by a self-adaptive timing design. Finally, the SRAM design was implemented and tested in the Austriamicrosystems (AMS) 0.35 ?m standard CMOS process. The prototype chips are adapted to work with frequencies up to 80 MHz, power supply voltages from 2.9 V to 3.3 V and temperatures from 0 °C to 60 °C. The single event latchup (SEL) tolerance is improved from 5.2 MeV cm2/mg to above 56 MeV cm2/mg. The total ionizing dose (TID) tolerance is enhanced by the P+ guard rings and the self-adaptive timing design. The single event upset (SEU) effects are also alleviated due to the high SNM SRAM cell and the P+ guard rings. In the near future, the presented SRAM will be integrated in the CPS chips for the STAR experiments.

Wei, Xiaomin; Gao, Deyuan; Doziere, Guy; Hu, Yann

2013-02-01

127

Radiation hardening of components and systems for nuclear rocket vehicle applications  

NASA Technical Reports Server (NTRS)

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

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

1972-01-01

128

Spaceflight Ka-Band High-Rate Radiation-Hard Modulator  

NASA Technical Reports Server (NTRS)

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

Jaso, Jeffery M.

2011-01-01

129

The Very Bright and Nearby GRB130427A: the Extra Hard Spectral Component and Implications for Very High-Energy Gamma-Ray Observations of Gamma-Ray Bursts  

NASA Astrophysics Data System (ADS)

The extended high-energy gamma-ray (>100 MeV) emission occurring after the prompt gamma-ray bursts (GRBs) is usually characterized by a single power-law spectrum, which has been explained as the afterglow synchrotron radiation. We report on the Fermi Large Area Telescope (LAT) observations of the >100 MeV emission from the very bright and nearby GRB 130427A, up to 100 GeV. By performing time-resolved spectral fits of GRB 130427A, we found a strong evidence of an extra hard spectral component above a few GeV that exists in the extended high-energy emission of this GRB. This extra spectral component may represent the first clear evidence of the long sought-after afterglow inverse Compton emission. Prospects for observations at the very high-energy gamma-rays, i.e., above 100 GeV, are described.

Tam, Pak-Hin Thomas

2014-03-01

130

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

E-print Network

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

Sibille, Jennifer Ann

2013-05-31

131

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

NASA Technical Reports Server (NTRS)

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.

Poivey, Christian

2003-01-01

132

Hard Photons Powerful Radiation of Electron Bunch Interacting with Plasma Beat Wayes  

NASA Astrophysics Data System (ADS)

Radiation process of electron bunch moving towards plasma beat waves is investigated. The plasma beat waves are excited by two laser pulses with difference of frequencies coinciding with plasma frequency. Then a strong longitudinally periodic electric field is generated. This brings to the longitudinal oscillations of bunch electrons with plasma frequency. As a result a powerful so called "hybrid radiation" is generated with combined properties of transition radiation and undulator radiation.

Shamamian, A.; Gevorgian, L.

2010-04-01

133

Radiation hardness of a polycrystalline chemical-vapor-deposited diamond detector irradiated with 14 MeV neutrons  

NASA Astrophysics Data System (ADS)

Chemical-vapor-deposited (CVD) diamond films are considered as neutron detectors for nuclear fusion devices because of their radiation hardness. Data about the radiation hardness of polycrystalline CVD diamond films exposed to 14 MeV neutron are missing in literature so the actual capability of CVD diamond detectors to withstand fusion device conditions must be truly demonstrated. In this work a polycrystalline CVD diamond detector, 101?m thick, was irradiated for the first time with 14 MeV neutrons produced by the Fusion Neutron Source of the Japan Atomic Energy Research Institute with the goal to study its radiation hardness. The 14 MeV neutron fluence was 8×1014n/cm2. The film performances were studied before and after the 14 MeV neutron irradiation by using 5.5 MeV ? from Am241 source, both in the pumped and the "as-grown" state. A comparison with previous measurements performed in more soft neutron spectra (mean neutron energy of 1-2 MeV) is reported pointing out the more damaging effects of the 14 MeV neutrons. It was found that annealing at 500 °C and redeposition of the gold contact followed by a proper pumping procedure will restore more than 70% the initial working conditions of the irradiated detector. An analysis of the neutron field expected in the neutron camera of the International Thermonuclear Reactor fusion tokamak was also performed, showing the capability of CVD diamond detector to withstand the 14 MeV neutron fluence expected in about one year of operation.

Angelone, M.; Pillon, M.; Balducci, A.; Marinelli, M.; Milani, E.; Morgada, M. E.; Pucella, G.; Tucciarone, A.; Verona-Rinati, G.; Ochiai, Kentaro; Nishitani, Takeo

2006-02-01

134

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

PubMed

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

Suzuki, Motohiro

2014-11-01

135

Radiation heat transfer in SOFC materials and components  

NASA Astrophysics Data System (ADS)

Radiative transport within the electrode and electrolyte layers, as well as surface-to-surface radiation within the fuel and oxygen flow channels, has the potential to dramatically influence temperature fields and overall operating conditions of solid oxide fuel cells (SOFCs). On a larger scale, radiation from the stack to the environment, including heat losses through insulation, must be accounted for in the plant design, and is of critical importance for effective thermal management of the high temperature stack. In this report, we discuss the current state-of-the-art and the challenges that remain in understanding, predicting, and quantifying the effects of radiation in SOFC materials and systems. These phenomena are of great interest and importance not only from a fundamental perspective but also from a systems design point of view. Last, but not the least in importance, the determination of radiative properties of the materials involved - either through experimental methods or predictive models - must be an ongoing effort as new materials are continuously being developed.

Damm, David L.; Fedorov, Andrei G.

136

Heat pipe radiation cooling of advanced hypersonic propulsion system components  

NASA Technical Reports Server (NTRS)

Heat transfer, heat pipe, and system studies were performed to assess the newly proposed heat pipe radiation cooling (HPRC) concept. With an HPRC system, heat is removed from the ramburner and nozzle of a hypersonic aircraft engine by a surrounding, high-temperature, heat pipe nacelle structure, transported to nearby external surfaces, and rejected to the environment by thermal radiation. With HPRC, the Mach number range available for using hydrocarbon fuels for aircraft operation extends into the Mach 4 to Mach 6 range, up from the current limit of about Mach 4. Heat transfer studies using a newly developed HPRC computer code determine cooling system and ramburner and nozzle temperatures, heat loads, and weights for a representative combined-cycle engine cruising at Mach 5 at 80,000 ft altitude. Heat pipe heat transport calculations, using the Los Alamos code HTPIPE, reveal that adequate heat trasport capability is available using molybdenum-lithium heat pipe technology. Results show that the HPRC system radiator area is limited in size to the ramburner-nozzle region of the engine nacelle; reasonable system weights are expected; hot section temperatures are consistent with advanced structural materials development goals; and system impact on engine performance is minimal.

Martin, R. A.; Keddy, M.; Merrigan, M. A.; Silverstein, C. C.

1991-01-01

137

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

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

138

Space Radiation Shielding Studies for Astronaut and Electronic Component Risk Assessment  

NASA Technical Reports Server (NTRS)

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

Fuchs, Jordan Robert

2010-01-01

139

RADIATION HARDNESS / TOLERANCE OF SI SENSORS / DETECTORS FOR NUCLEAR AND HIGH ENERGY PHYSICS EXPERIMENTS.  

SciTech Connect

Silicon sensors, widely used in high energy and nuclear physics experiments, suffer severe radiation damage that leads to degradations in sensor performance. These degradations include significant increases in leakage current, bulk resistivity, and space charge concentration. The increase in space charge concentration is particularly damaging since it can significantly increase the sensor full depletion voltage, causing either breakdown if operated at high biases or charge collection loss if operated at lower biases than full depletion. Several strategies can be used to make Si detectors more radiation had tolerant to particle radiations. In this paper, the main radiation induced degradations in Si detectors will be reviewed. The details and specifics of the new engineering strategies: material/impurity/defect engineering (MIDE); device structure engineering (DSE); and device operational mode engineering (DOME) will be given.

LI,Z.

2002-09-09

140

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

NASA Technical Reports Server (NTRS)

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.

Barnes, C.; Johnston, A.

1999-01-01

141

FERMI OBSERVATIONS OF GRB 090510: A SHORT-HARD GAMMA-RAY BURST WITH AN ADDITIONAL, HARD POWER-LAW COMPONENT FROM 10 keV TO GeV ENERGIES  

SciTech Connect

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{sub 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 {approx}20 keV and above {approx}100 MeV. The onset of the high-energy spectral component appears to be delayed by {approx}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{sup +5.8}{sub -2.6} GeV, the highest ever measured from a short GRB. Observation of this photon sets a minimum bulk outflow Lorentz factor, {Gamma}{approx_gt} 1200, using simple {gamma}{gamma} opacity arguments for this GRB at redshift z = 0.903 and a variability timescale on the order of tens of ms for the {approx}100 keV-few MeV flux. Stricter high confidence estimates imply {Gamma} {approx_gt} 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.

Ackermann, M.; Bechtol, K.; Berenji, B.; Blandford, R. D.; Bloom, E. D.; Borgland, A. W.; Bouvier, A. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Asano, K. [Interactive Research Center of Science, Tokyo Institute of Technology, Meguro City, Tokyo 152-8551 (Japan); Atwood, W. B. [Santa Cruz Institute for Particle Physics, Department of Physics and Department of Astronomy and Astrophysics, University of California at Santa Cruz, Santa Cruz, CA 95064 (United States); Axelsson, M. [Department of Astronomy, Stockholm University, SE-106 91 Stockholm (Sweden); Baldini, L.; Bellazzini, R.; Bregeon, J. [Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa (Italy); Ballet, J. [Laboratoire AIM, CEA-IRFU/CNRS/Universite Paris Diderot, Service d'Astrophysique, CEA Saclay, 91191 Gif sur Yvette (France); Barbiellini, G. [Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, I-34127 Trieste (Italy); Baring, M. G. [Department of Physics and Astronomy, Rice University, MS-108, P.O. Box 1892, Houston, TX 77251 (United States); Bastieri, D. [Istituto Nazionale di Fisica Nucleare, Sezione di Padova, I-35131 Padova (Italy); Bhat, P. N. [Center for Space Plasma and Aeronomic Research (CSPAR), University of Alabama in Huntsville, Huntsville, AL 35899 (United States); Bissaldi, E. [Max-Planck Institut fuer extraterrestrische Physik, 85748 Garching (Germany); Bonamente, E., E-mail: jchiang@slac.stanford.ed, E-mail: sylvain.guiriec@lpta.in2p3.f, E-mail: j.granot@herts.ac.u, E-mail: ohno@astro.isas.jaxa.j [Istituto Nazionale di Fisica Nucleare, Sezione di Perugia, I-06123 Perugia (Italy)

2010-06-20

142

Single-shot analysis of hard x-ray laser radiation using a noninvasive grating spectrometer.  

PubMed

We present a spectrometer setup based on grating dispersion for hard x-ray free-electron lasers. This setup consists of a focusing spectrometer grating and a charge-integrating microstrip detector. Measurement results acquired at Linac Coherent Light Source are presented, demonstrating noninvasive monitoring of single-shot spectra with a resolution of 2.0×10(-4) ±0.3×10(-4) at photon energy of 6 keV with more than 95% transmission of the main beam. PMID:23258009

Karvinen, Petri; Rutishauser, Simon; Mozzanica, Aldo; Greiffenberg, Dominic; Jurani?, Pavle N; Menzel, Andreas; Lutman, Alberto; Krzywinski, Jacek; Fritz, David M; Lemke, Henrik T; Cammarata, Marco; David, Christian

2012-12-15

143

Radiative decay Y (4260 )?X (3872 )+? involving hadronic molecular and charmonium components  

NASA Astrophysics Data System (ADS)

We apply a phenomenological Lagrangian approach to the radiative decay Y (4260 )?X (3872 )+? . 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.

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

2014-10-01

144

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

SciTech Connect

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.

NONE

1990-07-15

145

A Numerical Study of Material Parameter Sensitivity in the Production of Hard Metal Components Using Powder Compaction  

NASA Astrophysics Data System (ADS)

Modeling of hard metal powder inserts is analyzed based on a continuum mechanics approach. In particular, one commonly used cutting insert geometry is studied. For a given advanced constitutive description of the powder material, the material parameter space required to accurately model the mechanical behavior is determined. These findings are then compared with the corresponding parameter space that can possibly be determined from a combined numerical/experimental analysis of uniaxial die powder compaction utilizing inverse modeling. The analysis is pertinent to a particular WC/Co powder and the finite element method is used in the numerical investigations of the mechanical behavior of the cutting insert.

Andersson, Daniel C.; Lindskog, Per; Staf, Hjalmar; Larsson, Per-Lennart

2014-06-01

146

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

NASA Astrophysics Data System (ADS)

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

Spartiotis, Konstantinos; Pyyhtiä, Jouni; Schulman, Tom

2003-11-01

147

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

NASA Astrophysics Data System (ADS)

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.

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

2014-09-01

148

Distribution of toxic and radiation components in air particulates.  

PubMed

The concentrations of several toxic heavy metals and volatile organic compounds (VOCs) in various types of Hungarian fly-ash fine particulates were investigated by means of instrumental neutron activation analysis, X-ray fluorescence analysis and gas chromatography, coupled with mass spectrometry. Within a power station, particulate samples were taken from the boiler zone (BO), from the electrostatic dust filter chamber (FI) and from the flue-gas at the top of the stack (ST). Enrichment rates of the toxic metals both in FI and ST particulate fractions related to the BO concentrations were calculated to enable the temperature dependence on the adsorption of the toxic components to be studied. In addition, both the total amounts of the VOCs and their partial distributions in accordance with the number of carbon atoms were also studied in fly-ash particulates. From them, 31 organic species were identified and determined. Since Hungarian brown coals have high uranium and thorium contents, the specific radioactivities of the daughter isotopes of both the 232Th and 238U decay series were also measured and are discussed. PMID:8560225

Rausch, H; Sziklai, I L; Borossay, J; Torkos, K; Rikker, T; Zemplén-Papp, E

1995-12-01

149

Radiation Hardness Tests of a Scintillation Detector with Wavelength Shifting Fiber Readout  

SciTech Connect

We have performed radiation tolerance tests on the BCF-99-29MC wavelength shifting fibers and the BC404 plastic scintillator from Bicron as well as on silicon rubber optical couplers. We used the 60Co gamma source at the Instituto de Ciencias Nucleares facility to irradiate 30-cm fiber samples with doses from 50 Krad to 1 Mrad. We also irradiated a 10x10 cm2 scintillator detector with the WLS fibers embedded on it with a 200 krad dose and the optical conectors between the scintillator and the PMT with doses from 100 to 300 krad. We measured the radiation damage on the materials by comparing the pre- and post-irradiation optical transparency as a function of time.

Alfaro, R.; Sandoval, A. [Instituto de Fisica - UNAM (Mexico); Cruz, E.; Martinez, M. I.; Paic, G. [Instituto de Ciencias Nucleares - UNAM (Mexico); Montano, L. M. [CINVESTAV (Mexico)

2006-09-25

150

Impact of radiation hardness and operating temperatures of silicon carbide electronics on space power system mass  

Microsoft Academic Search

The effect of silicon carbide (SiC) electronics operating temperatures on Power Management and Distribution (PMAD), or Power Conditioning (PC), subsystem radiator size and mass requirements was evaluated for three power output levels (100 kWe, 1 MWe, and 10 MWe) for near term technology (i.e. 1500 K turbine inlet temperature) Closed Cycle Gas Turbine (CCGT) power systems with a High Temperature

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

1999-01-01

151

Impact of radiation hardness and operating temperatures of silicon carbide electronics on space power system mass  

Microsoft Academic Search

The effect of silicon carbide (SiC) electronics operating temperatures on Power Management and Distribution (PMAD), or Power Conditioning (PC), subsystem radiator size and mass requirements was evaluated for three power output levels (100 kWe,1 MWe, and 10 MWe) for near term technology (i.e. 1500 K turbine inlet temperature) Closed Cycle Gas Turbine (CCGT) power systems with a High Temperature Gas

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

1999-01-01

152

Radiation-hard design principles utilized in CMOS 8085 microprocessor family  

Microsoft Academic Search

A microprocessor family has been designed in radiation-hardened bulk, silicon-gate CMOS and the three main family members are logic emulations of Intel NMOS devices: SA3000, a general-purpose 8-bit central processing unit (CPU) (Intel 8085A); SA3001, a 256 x 8-bit static RAM with two 8-bit I\\/O ports, one 6-bit I\\/O port and a timer (Intel 8155\\/56); SA3002, a 2K x 8-bit

W. S. Kim; T. M. Mnich; W. T. Corbett; R. K. Treece; A. E. Giddings; J. L. Jorgensen

1983-01-01

153

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

Microsoft Academic Search

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

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

154

GaAs ICs for new defense systems offer speed and radiation hardness benefits  

Microsoft Academic Search

In connection with rapid technical growth affecting the world of electronic warfare (EW), it will be necessary to design both electronic support measure and electronic countermeasure systems with improved algorithms and processing techniques. The designs will have to be implemented with higher speed electronic components. It is pointed out that the performance advantages of GaAs integrated circuits, particularly in the

A. Firstenberg; S. Rooslid

1985-01-01

155

Performance of Multilayer Monochromators for Hard X-Ray Imaging with Coherent Synchrotron Radiation  

NASA Astrophysics Data System (ADS)

We present a study in which multilayers of different periodicity (from 2.5 to 5.5 nm), composition (W/Si, Mo/Si, Pd/B4C, Ru/B4C), and numbers of layers have been compared. Particularly, we chose mirrors with similar intrinsic quality (roughness and reflectivity) to study their performance (flatness and coherence of the outgoing beam) as monochromators in synchrotron radiography. The results indicate that material composition is the dominating factor for the performance. This is important to consider for future developments in synchrotron-based hard x-ray imaging methods. In these techniques, multilayer monochromators are popular because of their good tradeoff between spectral bandwidth and photon flux density of the outgoing beam, but sufficient homogeneity and preservation of the coherent properties of the reflected beam are major concerns. The experimental results we collected may help scientists and engineers specify multilayer monochromators and can contribute to better exploitation of the advantages of multilayer monochromators in microtomography and other full-field imaging techniques.

Dietsch, R.; Rack, A.; Weitkamp, T.; Riotte, M.; Rack, T.; Holz, T.; Krämer, M.; Weissbach, D.; Morawe, Ch.; Siewert, F.; Medu?a, M.; Cloetens, P.; Ziegler, E.

2011-09-01

156

Proton radiation hardness of single-nanowire transistors using robust organic gate nanodielectrics  

SciTech Connect

In this contribution, the radiation tolerance of single ZnO nanowire field-effect transistors (NW-FETs) fabricated with a self-assembled superlattice (SAS) gate insulator is investigated and compared with that of ZnO NW-FETs fabricated with a 60 nm SiO{sub 2} gate insulator. A total-radiation dose study was performed using 10 MeV protons at doses of 5.71 and 285 krad(Si). The threshold voltage (V{sub th}) of the SAS-based ZnO NW-FETs is not shifted significantly following irradiation at these doses. In contrast, V{sub th} parameters of the SiO{sub 2}-based ZnO NW-FETs display average shifts of {approx}-4.0 and {approx}-10.9 V for 5.71 and 285 krad(Si) H{sup +} irradiation, respectively. In addition, little change is observed in the subthreshold characteristics (off current, subthreshold slope) of the SAS-based ZnO NW-FETs following H{sup +} irradiation. These results strongly argue that the bulk oxide trap density and interface trap density formed within the SAS and/or at the SAS-ZnO NW interface during H{sup +} irradiation are significantly lower than those for the corresponding SiO{sub 2} gate dielectrics. The radiation-robust SAS-based ZnO NW-FETs are thus promising candidates for future space-based applications in electronics and flexible displays.

Ju, Sanghyun; Lee, Kangho; Janes, David B.; Dwivedi, Ramesh C.; Baffour-Awuah, Habibah; Wilkins, R.; Yoon, Myung-Han; Facchetti, Antonio; Mark, Tobin J. [School of Electrical and Computer Engineering, The Institute for Nanoelectronics and Computing, and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States); NASA/Center for Applied Radiation Research (CARR), and Department of Electrical Engineering, Prairie View A and M University, Prairie View, Texas 77446 (United States); Department of Chemistry, and the Materials Research Center, and the Institute for Nanoelectronics and Computing, Northwestern University, Evanston, Illinois 60208-3113 (United States); Northwestern University, Evanston, Illinois 60208-3113 (United States)

2006-08-14

157

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

NASA Astrophysics Data System (ADS)

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.

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

158

Beta Backscatter Measures the Hardness of Rubber  

NASA Technical Reports Server (NTRS)

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

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

1986-01-01

159

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

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

Scofield, John H.

160

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

PubMed Central

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

Schroer, Christian G.; Falkenberg, Gerald

2014-01-01

161

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

PubMed

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

Schroer, Christian G; Falkenberg, Gerald

2014-09-01

162

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

NASA Astrophysics Data System (ADS)

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

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

1999-01-01

163

Radiation hardness studies in a CCD with high-speed column parallel readout  

NASA Astrophysics Data System (ADS)

Charge Coupled Devices (CCDs) have been successfully used in several high energy physics experiments over the past two decades. Their high spatial resolution and thin sensitive layers make them an excellent tool for studying short-lived particles. The Linear Collider Flavour Identification (LCFI) collaboration is developing Column-Parallel CCDs (CPCCDs) for the vertex detector of the International Linear Collider (ILC). The CPCCDs can be read out many times faster than standard CCDs, significantly increasing their operating speed. The results of detailed simulations of the charge transfer inefficiency (CTI) of a prototype CPCCD including the variation of model parameters are reported. The effects of bulk radiation damage on the CTI of a CPCCD are studied by simulating the effects of two electron trap levels, 0.17 and 0.44 eV, at different concentrations and operating temperatures. The dependence of the CTI on different occupancy levels (percentage of hit pixels) and readout frequencies is also studied. The optimal operating temperature for the CPCCD, where the effects of the charge trapping are at a minimum, is found to be about 230 K for the range of readout speeds proposed for the ILC. The results of the full simulation have been compared with an analytic model.

Sopczak, A.; Aoulmit, S.; Bekhouche, K.; Bowdery, C.; Buttar, C.; Damerell, C.; Davies, G.; Djendaoui, D.; Dehimi, L.; Greenshaw, T.; Koziel, M.; Maneuski, D.; Stefanov, K.; Tikkanen, T.; Woolliscroft, T.; Worm, S.

2008-05-01

164

The Effect of Hard Radiation on the Electronic, Optical, and Recombination Properties of the (Al, Ga, In)-P and (Al, Ga)-As Compounds and their Solid Solutions  

NASA Astrophysics Data System (ADS)

The data of the experimental and theoretical investigations into the electronic, optical, and recombination properties of AlP, InP, GaP, AlAs, GaAs, and their solid solutions exposed to hard radiation are discussed. The influence of hard radiation on the properties of laser and light-emitting diode (LED) structures based on these materials is analyzed.

Brudnyi, V. N.

2013-12-01

165

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

NASA Astrophysics Data System (ADS)

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.

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

2014-09-01

166

WHAT is the radiation budget? The Earth's radiation budget fundamentally comprises of two components. Incoming shortwave  

E-print Network

using cloud ice data, water vapour and temperature profiles from the NASA A-Train Microwave Limb Sounder the Aqua A-train platform. The likely radiative effect of upper tropospheric clouds and water vapour, which is a function of temperature. Clouds, aerosols, water vapour and other greenhouse gases play a key

167

Electronic Components and Systems and their Radiation Qualification for Use in the LHC Machine  

E-print Network

Studies, taking into account the expected radiation doses for the different sections in the LHC accelerator tunnel, such as regular arcs and dispersion suppressors, show that electronic equipment can be considered for installation under the magnets. An estimate based on work carried out for String 2, the LHC Magnet String Program and extrapolated to the whole LHC machine gives a total of several thousands electronic crates to be housed under the magnets. This represents a substantial installation and a large expenditure. In order to qualify electronic equipment for installation in the LHC tunnel, from its radiation hardness point of view at the dose levels considered, an on-line radiation test facility has ben created and installed along a secondary beam line in the north experimental area of the SPS accelerator. The object of this paper is to present the type of electronic equipment and systems planned to be installed in the tunnel of the LHC and to give some preliminary results on radiation tests made for t...

Rausch, R

1999-01-01

168

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

NASA Technical Reports Server (NTRS)

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.

Becher, J.; Kernell, R. L.

1981-01-01

169

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

NASA Astrophysics Data System (ADS)

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

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

2013-08-01

170

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

NASA Astrophysics Data System (ADS)

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.

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

2006-01-01

171

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

PubMed

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

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

2006-01-01

172

Radiation effects on optical components of a laser radar sensor designed for remote metrology in ITER  

SciTech Connect

A frequency modulated laser radar is being developed for in-vessel metrology and viewing of plasma-facing surfaces. Some optical components of this sensor must withstand intense gamma radiation (3 {times} 10{sup 6} rad/h) during operation. The authors have tested the effect of radiation on a silica core polarization maintaining optical fiber and on TeO{sub 2} crystals at doses up to {approximately} 10{sup 9} rad. Additional tests are planned for evaluating the performance of a complete acousto-optic (AO) scanning device. The progress made in these tests is also described.

Menon, M.M.; Grann, E.B. [Oak Ridge National Lab., TN (United States); Slotwinski, A. [Coleman Research Corp., Springfield, VA (United States)

1997-09-01

173

Evaluation of 20-min and Annual Radiation Budget Components and Cloudiness in a Mountainous Valley  

NASA Astrophysics Data System (ADS)

Logan, Utah (USA) is among cities located in the mountainous valley in the western portion of Rocky Mountains in North America. It is the county seat of Cache Valley, a metropolitan area with a population of about 100,000. The valley had the polluted air in the USA during January 2004. To evaluate the daily and annual radiation budget and cloudiness in this mountainous valley, we set up a radiation station in the middle of the valley to measure the 20- min radiation budget components namely: incoming (Rso) and outgoing (Rso) solar or shortwave radiation, using to CM21 Kipp and Zonen (one inverted) and incoming (Rli) (or atmospheric) and outgoing (Rlo) or terrestrial) longwave radiation using two CG1 Kipp and Zonen Pyrgeometers (one inverted) during the year of 2003. All pyranometers and Pyrgeometers were ventilated with four CV2 Kipp and Zonen ventilation systems throughout the year to prevent deposition of dew, frost and snow, which otherwise would disturb the measurements. We also measured the 2-m air temperature and relative humidity along with surface temperature. All measurements were taken every 2 s, averaged to 20 min, continuously throughout the year 2000. A Met One heated rain gauge measured precipitation. Comparison of the annual radiation budget components indicates that about 25% of the annual Rsi (5848.6 MJ/ (squared m-y)) was reflected back to sky as Rso. Rli and Rlo amounted to 9968.7 and 13303.5 MJ/ (squared m-y)), respectively. This yielded about 1364.9 MJ/ (squared m- y)) available energy (Rn). Having the 2-m air temperature and moisture data and comparison between the theoretical and the measured longwave radiation, we evaluated the 20-m cloudy conditions throughout the year of 2003. The average cloud base height was 587 m (ranged from zero for foggy conditions to about 3000 m). Annual cloudiness contributed about 139.1 MJ/ (squared m-y)) more energy in this valley.

Malek, E.

2007-05-01

174

Comparisons of Exact Results for the Virtual Photon Contribution to Single Hard Bremsstrahlung in Radiative Return for Electron-Positron Annihilation  

E-print Network

We compare fully differential exact results for the virtual photon correction to single hard photon bremsstrahlung obtained using independent calculations, both for electron-positron annihilation at high-energy colliders and for radiative return applications. The results are compared using Monte Carlo evaluations of the matrix elements as well as by direct analytical evaluation of certain critical limits. Special attention is given to the issues of numerical stability and the treatment of finite-mass corrections. It is found that agreement on the order of 10^{-5} or better is obtained over most of the range of hard photon energies, at CMS energies relevant to both high energy collisions and radiative return experiments.

S. Jadach; B. F. L. Ward; S. A. Yost

2006-02-21

175

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

NASA Astrophysics Data System (ADS)

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

Bardi, Marcelo Augusto Gonçalves; Machado, Luci Diva Brocardo

2012-09-01

176

An experimental test for the charge state of the 'anomalous' helium component. [galactic cosmic radiation  

NASA Technical Reports Server (NTRS)

Observations of phase lags between intensity variations for various particle species and energy ranges in the low-energy galactic cosmic radiation during the general intensity decrease observed in 1974-1975 show that, for particles whose charge state is known (i.e., 'normal' cosmic-ray components), particles with higher rigidities respond more quickly to changes in modulation conditions than do those with lower rigidities. When compared with particles of known energy and charge, the behavior of the 'anomalous' low-energy helium component is consistent with these observations only if the helium is singly rather than doubly charged.

Mckibben, R. B.

1977-01-01

177

Effect of small flares in the neutral component of secondary cosmic radiation  

NASA Technical Reports Server (NTRS)

The results are presented of an investigation of the effect of small flares, scale divisions 1 and 1(+), in the neutron component of secondary cosmic radiation from the data of neutron supermonitors at the stations of Kiev, Bukhta Tiksi, and Deep River. It is shown that flares of scale divisions 1 and 1(+) are accompanied by an effect in the neutron component amounting to about 0.4%. A mechanism is presented for calculating the outflow of particles accelerated in small flares, owing to diffusion across the magnetic field of a trap.

Bondarenko, V. I.; Raychenko, L. V.; Yukhimuk, A. K.

1974-01-01

178

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

E-print Network

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

Michael A. Ivanov

2006-09-19

179

The attenuation length of the high energy nucleonic component of the cosmic radiation near sea level  

Microsoft Academic Search

Summary  From the analysis of neutron data obtained at two widely separated stations, it is shown that during 1957 the attenuation\\u000a length of the high energy nucleonic component of the cosmic radiation near sea level was (138.1±0.8) g cm?2 at high geomagnetic latitudes. Analysis of data from a number of stations shows that the amplitudes of Forbush type decreases\\u000a increase by

K. G. McCracken; D. H. Johns

1959-01-01

180

Radiation Test Programme On Cots Components Needed For The Large Hadron Collider At Cern  

E-print Network

The future Large Hadron Collider to be built at CERN will use superconducting magnets cooled down to 1.2 K. To preserve the superconductivity, the energy deposition resulting from beam losses must be kept at a minimum level. As a consequence, the radiation doses will also be low; the absorbed dose levels in the components located outside the cryostat, in the tunnel, are calculated to be of the order of 1 to 10 Gy per year.

Rausch And Tavlet; R. Rausch; R. Rausch; M. Tavlet; M. Tavlet

181

A principal component-based radiative transfer forward model (PCRTM) for hyperspectral instruments  

NASA Astrophysics Data System (ADS)

Modern Infrared satellite sensors such as AIRS, CrIS, TES, GIFTS and IASI are all capable of providing high spatial and spectral resolution infrared spectra. To fully exploit the vast amount of spectral information from these instruments, super fast radiative transfer models are needed. This paper presents a novel radiative transfer model based on principal component analysis. The model is very accurate and flexible. Its execution speed is a factor of 3-30 times faster than channel-based fast models. Due to its high speed and compressed spectral information format, it has great potential for super fast one-dimensional physical retrievals and for Numerical Weather Prediction (NWP) large volume radiance data assimilation applications. The model has been successfully developed for the NAST-I and AIRS instruments. The PCRTM model performs monochromatic radiative transfer calculations and is suitable to include multiple scattering calculations to account for clouds and aerosols.

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

2005-01-01

182

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

NASA Astrophysics Data System (ADS)

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

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

2012-08-01

183

A critical assessment of direct radiative effects of different aerosol types on surface global radiation and its components  

NASA Astrophysics Data System (ADS)

A critical assessment of direct radiative effects of different aerosol types on surface global, direct and diffuse radiation is presented. The analysis is based on measurements of aerosol optical properties and surface solar radiation (SSR) of cloud-free days at the Baseline Surface Radiation Network (BSRN) and Aerosol Robotic Network station (AERONET) of Xianghe over the North China Plain between October 2004 and May 2012. Six aerosol types are classified based on aerosol size and absorption from the AERONET retrieval products, including two coarse-mode dominated aerosol types: dust (DU: fine mode fraction (FMF)<0.4) and polluted dust (PD: FMF within 0.4-0.7) and four fine-mode dominated aerosol types (FMF>0.7) but with different single scattering albedo (SSA): highly absorbing (HA: SSA<0.85), moderately absorbing (MA: SSA within 0.85-0.90), slightly absorbing (SA: SSA within 0.90-0.95) and very weakly absorbing (WA: SSA>0.95). Dramatic differences in aerosol direct radiative effect (ADRE) on global SSR and its components between the six aerosol types have been revealed. ADRE efficiency on global SSR for solar zenight angle (SZA) between 55° and 65° ranges from -106 W m-2 for WA to -181 W m-2 for HA. The minimum ADRE efficiency on diffuse SSR is derived for HA aerosols, being 113 W m-2 that is about half of that by DU, the maximum value of six aerosol types. ADRE efficiency on global SSR by DU and PD (-141 to -150 W m-2 for SZA between 55° and 65°) is comparable to that by MA, although 100 W m-2 more direct SSR is extincted by DU and PD than by MA. DU and PD induce more diffuse SSR than MA that offsets larger reduction of direct SSR by DU and PD. Implications of the results to related researches are detailed discussed. The results are derived from aerosol and radiation data in the North China Plain, however the method can be used to any other stations with similar measurements.

Xia, Xiangao

2014-12-01

184

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

NASA Technical Reports Server (NTRS)

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

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

1999-01-01

185

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

NASA Astrophysics Data System (ADS)

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

Jacobs, Geoffrey P.

1998-11-01

186

3-mm anisotropy measurement and the quadrupole component in the cosmic background radiation  

SciTech Connect

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

Lubin, P.M.; Epstein, G.L.; Smoot, G.F.

1983-02-21

187

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

SciTech Connect

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.

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

1982-11-01

188

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

NASA Technical Reports Server (NTRS)

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

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

1993-01-01

189

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

NASA Astrophysics Data System (ADS)

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

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

1993-01-01

190

Development of an Adaptive Optical System for Sub-10-nm Focusing of Synchrotron Radiation Hard X-rays  

SciTech Connect

In the hard x-ray region, to obtain the theoretical resolution or diffraction-limited focusing size in an imaging optical system, both ultraprecise optics and highly accurate alignment are necessary. An adaptive optical system is used for the compensation of aberrations in various optical systems, such as optical microscopes and space telescopes. In situ wavefront control of hard x-rays is also effective for realizing ideal performance. The aim of this paper is to develop an adaptive optical system for sub-10-nm hard x-ray focusing. The adaptive optical system performs the wavefront measurement using a phase retrieval algorithm and wavefront control using grazing-incidence deformable mirrors. Several results of experiments using the developed system are reported.

Mimura, H.; Kimura, T.; Matsuyama, S. [Department of Precision Science and Technology, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); JST CREST, Yamada-oka, Suita, Osaka 565-0871 (Japan); Yokoyama, H. [Department of Precision Science and Technology, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); Yumoto, H. [SPring-8/JASRI, 1-1-1 Koto Sayo, Hyogo 679-5148 (Japan); Tamasaku, K.; Koumura, Y.; Yabashi, M. [SPring-8/RIKEN, 1-1-1 Koto Sayo, Hyogo 679-5148 (Japan); Ishikawa, T. [SPring-8/JASRI, 1-1-1 Koto Sayo, Hyogo 679-5148 (Japan); SPring-8/RIKEN, 1-1-1 Koto Sayo, Hyogo 679-5148 (Japan); Yamauchi, K. [Department of Precision Science and Technology, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); JST CREST, Yamada-oka, Suita, Osaka 565-0871 (Japan); Center for Ultraprecision Science and Technology, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan)

2011-09-09

191

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

Microsoft Academic Search

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

A. Fernandez Fernandez

2001-01-01

192

A proposed hardness assurance test methodology for bipolar linear circuits and devices in a space ionizing radiation environment  

Microsoft Academic Search

A hardness assurance test approach has been developed for bipolar linear circuits and devices in space. It consists of an initial test for dose rate sensitivity and a characterization test method to develop the conditions for a lot acceptance test at high dose rate. For parts with adequate design margin and\\/or well behaved parts a generic elevated temperature irradiation test

Ronald L. Pease; Lewis M. Cohn; Daniel M. Fleetwood; Mark A. Gehlhausen; Tom L. Turflinger; Dennis B. Brown; Allan H. Johnston

1997-01-01

193

Radiation hardness studies of CdTe and HgI2 for the SIXS particle detector on-board the BepiColombo spacecraft  

NASA Astrophysics Data System (ADS)

We report of the radiation hardness measurements that were performed in the developing work of a particle detector on-board ESA's forthcoming BepiColombo spacecraft. Two different high- Z semiconductor compounds, cadmium telluride (CdTe) and mercuric iodide (HgI 2), were irradiated with 22 MeV protons in four steps to attain the estimated total dose of 1012 p/cm2 for the mission time. The performance of the detectors was studied before and after every irradiation with radioactive 55Fe source Mn K ? 5.9 keV emission line. We studied the impact of the proton beam exposure on detector leakage current, energy resolution and charge collection efficiency (CCE). Also the reconstructive effect of annealing on radiation induced damage was tested for CdTe detector.

Ahoranta, J.; Uunila, M.; Huovelin, J.; Andersson, H.; Vainio, R.; Virtanen, A.; Kettunen, H.

2009-07-01

194

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

NASA Technical Reports Server (NTRS)

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

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

2010-01-01

195

Radiation emission by extreme relativistic electrons and pair production by hard photons in a strong plasma wakefield.  

PubMed

The radiation spectrum of extreme relativistic electrons and the probability of electron-positron pair production by energetic photons in a strong plasma wakefield are derived in the framework of a semiclassical approach. It is shown that the radiation losses of a relativistic electron in the plasma wakefield scale proportionally to epsilon2/3 in the quantum limit when the energy of the radiated photon becomes close to the electron energy epsilon . The quantum effects will play a key role in future plasma-based accelerators operating at ultrahigh electron energy. PMID:17677200

Nerush, E; Kostyukov, I

2007-05-01

196

Flavoring components of raw monsooned arabica coffee and their changes during radiation processing.  

PubMed

Volatile aroma principles, nonvolatile taste constituents (caffeine and chlorogenic and caffeic acids), and glycosidically bound aroma compounds of monsooned and nonmonsooned raw arabica coffee were analyzed using gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC). Among the most potent odor active constituents known to contribute to the aroma of the green beans, 3-isopropyl-2-methoxypyrazine, 3-isobutyl-2-methoxypyrazine, 4-vinylguaiacol, beta-damascenone, (E)-2-nonenal, trans,trans-2,4-decadienal, phenylacetaldehyde, and 3-methylbutyric acid were detected by GC-MS in both samples. A decrease in content of methoxypyrazines and an increase in 4-vinylguaiacol and isoeugenol resulted in a dominant spicy note of monsooned coffee. These phenolic compounds exist partly as their glycosides, and their release from the bound precursors during monsooning accounted for their higher content in monsooned coffee. A considerable decrease in astringent chlorogenic acid as a consequence of hydrolysis to bitter caffeic acid was noted in monsooned coffee. Radiation processing of nonmonsooned beans at a dose of 5 kGy resulted in an increased rate of monsooning. At this dose a quantitative increase in most of the aroma active components could be observed in all samples studied. Hydrolysis of chlorogenic acid to caffeic acid was noted in radiation-processed monsooned coffee beans irrespective of whether the treatment was carried out before or after monsooning. These changes were, however, not observed in irradiated, nonmonsooned coffee beans, suggesting an enzymatic rather than a radiolytic cleavage of chlorogenic acid. A rationale behind the mechanism of monsooning and radiation-induced enhancement of the monsooning process is discussed. PMID:14690378

Variyar, Prasad S; Ahmad, Rasheed; Bhat, Rajeev; Niyas, Zareena; Sharma, Arun

2003-12-31

197

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

E-print Network

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

Nagpal, Charu

2008-10-10

198

RHOBOT: Radiation hardened robotics  

SciTech Connect

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

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

1997-10-01

199

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

SciTech Connect

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)

Fluke, D.J.

1984-08-01

200

Comparative study of UV radiation hardness of n+p and p+n duo-lateral position sensitive detectors  

NASA Astrophysics Data System (ADS)

We report experimental results on the degree of radiation damage in two duo-lateral position sensitive detectors (LPSDs) exposed to 193 nm and 253 nm ultraviolet (UV) beam. One of the detectors was an in-house fabricated n+p LPSD and the other was a commercially available p+n LPSD. We report that at both wavelengths, the degradation damage from the UV photons absorption caused a much more significant deterioration in responsivity in the p+n LPSD than in the n+p LPSD. By employing a simple method, we were able to visualize the radiation damage on the active area of the LPSDs using 3-dimensional graphs. We were also able to characterize the impact of radiation damage on the linearity and position error of the detectors.

Xerviar Esebamen, Omeime; Thungström, Göran; Nilsson, Hans-Erik; Lundgren, Anders

2014-11-01

201

Effects of simulated space radiation on immunoassay components for life-detection experiments in planetary exploration missions.  

PubMed

The Life Marker Chip (LMC) instrument is part of the proposed payload on the ESA ExoMars rover that is scheduled for launch in 2018. The LMC will use antibody-based assays to detect molecular signatures of life in samples obtained from the shallow subsurface of Mars. For the LMC antibodies, the ability to resist inactivation due to space particle radiation (both in transit and on the surface of Mars) will therefore be a prerequisite. The proton and neutron components of the mission radiation environment are those that are expected to have the dominant effect on the operation of the LMC. Modeling of the radiation environment for a mission to Mars led to the calculation of nominal mission fluences for proton and neutron radiation. Various combinations and multiples of these values were used to demonstrate the effects of radiation on antibody activity, primarily at the radiation levels envisaged for the ExoMars mission as well as at much higher levels. Five antibodies were freeze-dried in a variety of protective molecular matrices and were exposed to various radiation conditions generated at a cyclotron facility. After exposure, the antibodies' ability to bind to their respective antigens was assessed and found to be unaffected by ExoMars mission level radiation doses. These experiments indicated that the expected radiation environment of a Mars mission does not pose a significant risk to antibodies packaged in the form anticipated for the LMC instrument. PMID:22897155

Derveni, Mariliza; Hands, Alex; Allen, Marjorie; Sims, Mark R; Cullen, David C

2012-08-01

202

ARTICLES: Synthesis of holographic components for optical data storage and transmission systems allowing for characteristics of semiconductor laser radiation  

Microsoft Academic Search

An analysis is made of the theoretical processes of computer synthesis of Fourier holograms for a holographic permanent memory system, and of focusing and collimating kinoform components for optical communication lines. An allowance is made for the characteristics of radiation of semiconductor lasers. The transfer function is determined for a Fourier hologram in a memory capable of compensating largely for

A. Akaev

1982-01-01

203

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

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

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

2012-06-01

204

Angular Dependence of the Radiative Gluon Spectrum and the Energy Loss of Hard Jets in QCD Media  

E-print Network

The induced momentum spectrum of soft gluons radiated from a high energy quark propagating through a QCD medium is derived in the BDMPS formalism. A calorimetric measurement for the medium dependent energy lost by a jet with opening angle $\\theta_{{\\rm cone}}$ is proposed.The fraction of this energy loss with respect to the integrated one appears to be the relevant observable.It exhibits a universal behaviour in terms of the variable $\\theta^2_{{\\rm cone}} L^3 \\hat q$ where $L$ is the size of the medium and $\\hat q$ the transport coefficient. Phenomenological implications for the differences between cold and hot QCD matter are discussed.

R. Baier; Yu. L. Dokshitzer; A. H. Mueller; D. Schiff

1999-07-07

205

A comparison of field-only electronic portal imaging hard copies with double exposure port films in radiation therapy treatment setup confirmation to determine its clinical application in a radiotherapy center  

Microsoft Academic Search

Purpose: To determine in which treatment sites field-only hard copy electronic portal images (EPI) captured during a treatment exposure could replace traditional double exposed port films in a busy radiation oncology department.Methods and Materials: The three linear accelerators in the William Buckland Radiotherapy Centre (WBRC) at the Alfred Hospital in Melbourne are each equipped with an electronic portal imaging device

Kay Hatherly; Josephine Smylie; Alan Rodger

1999-01-01

206

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

NASA Astrophysics Data System (ADS)

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.

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

207

Constant-pitch microprism-array optical device for beam condensers in hard x-ray synchrotron radiation beamlines  

NASA Astrophysics Data System (ADS)

A constant-pitch microprism-array optical device has been developed. It is a modified version of the previously reported quasi-Fresnel lens [Kagoshima et al., Appl. Phys. Lett. 101, 163102 (2012)]. The modification eases the fabrication of the lens, although it degrades some of the focusing performance. It consists of twenty 50-?m-wide right-angle microprisms, whose slope angles gradually increase to 67.8° at the outer side. By inclining the array, the aspect ratio of the microprisms becomes large enough for X-ray use. The effective slope angle can be enlarged to 86.4° at an inclination angle of 80.5°. A 10-keV synchrotron beam with a size of 680 ?m (V) × 660 ?m (H) was two-dimensionally condensed to 130 ?m (V) × 380 ?m (H) with a photon flux density gain of ˜3. We also show that the microprism array is suitable for practical use below the critical radiation dose rate.

Kagoshima, Y.; Takano, H.; Takeda, S.

2013-06-01

208

Active Radiation Monitoring Sensors for the High-Energy Physics  

E-print Network

; Validation test in "LHC-like" environment; Integration issues at the LHC Experiments; Conclusions damage are not expected, but · Some components might be not well qualified in radiation hardness; · Some long-term effects in complex radiation field are not predictable; Radiation level survey needed

209

Radiation tolerance qualification for maintenance tasks in the future fusion reactors: from fibre-optic components to robust data links  

Microsoft Academic Search

The future International Thermonuclear Experimental Reactor (ITER) requires remote handling tools for its maintenance that will operate in a harsh environment. The numerous instrumentation cables for this maintenance equipment call for (de)multiplexing solutions, in order to reduce the umbilical size. Fibre-optic data links, using commercial-off-the-shelf (COTS) components, are seriously considered as a radiation tolerant solution, offering wavelength encoded multiplexing possibilities.

M. Van Uffelen; A. Fernandez Fernandez; B. Brichard; F. Berghmans; M. Decréton

2003-01-01

210

Multi-component measurements of the Jefferson Lab energy recovery linac electron beam using optical transition and diffraction radiation  

SciTech Connect

DOI: http://dx.doi.org/10.1103/PhysRevSTAB.11.082801
High brightness electron accelerators, such as energy recovery linacs (ERL), often have complex particle distributions that can create difficulties in beam transport as well as matching to devices such as wigglers used to generate radiation from the beam. Optical transition radiation (OTR), OTR interferometry (OTRI) and optical diffraction-transition radiation interferometry (ODTRI) have proven to be effective tools for diagnosing both the spatial and angular distributions of charged particle beams. OTRI and ODTRI have been used to measure rms divergences and optical transverse phase space mapping has been demonstrated using OTRI. In this work we present the results of diagnostic experiments using OTR and ODR conducted at the Jefferson Laboratory 115 MeV ERL which show the presence of two separate components within the spatial and angular distributions of the beam. By assuming a correlation between the spatial and angular fe

Holloway, Michael; Fiorito, Ralph; Shkvarunets, Anatoly; O'Shea, Patrick; Benson, Stephen; Douglas, David; Evtushenko, Pavel; Jordan, Kevin

2008-08-01

211

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

E-print Network

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.

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

212

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

SciTech Connect

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

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

2010-11-01

213

Patient-Assessed Late Toxicity Rates and Principal Component Analysis After Image-Guided Radiation Therapy for Prostate Cancer  

SciTech Connect

Purpose: The aims of this study were to determine the incidence of patient-assessed late toxicity after high-dose, image-guided radiation therapy in a cohort of men with prostate cancer; and to correlate toxicity with conventional dosimetric parameters and rectal and bladder dose-volume histograms (DVH) reduced using principal component analysis. Methods and Materials: Toxicity questionnaires were sent to 690 men treated for localized prostate cancer to 75.6 Gy or 79.8 Gy using three-dimensional conformal radiation therapy (3DCRT) or intensity-modulated radiation therapy (IMRT) between 1997 and 2003 at the Princess Margaret Hospital. Toxicity was graded according to the modified Radiation Therapy Oncology Group (RTOG)-late effects normal tissue (LENT) scoring system. Late rectal and bladder toxicity scores were dichotomized as < Grade 2 and {>=} Grade 2, and correlated with dosimetric parameters and with the first three principal components of rectal and bladder DVHs. Results: In all, 63% of the patients completed the questionnaire. At a median follow-up of 37 months, the incidence of late rectal toxicity RTOG Grades 1, 2, and 3 was 25.2%, 2.5%, and 0.7% respectively. The incidence of late urinary toxicity RTOG Grade 1, 2, and 3 was 16.5%, 8.8%, and 0.9% respectively. Maintenance of erectile function sufficient for intercourse was reported in 68%. No dosimetric parameter analyzed, including principal component analysis reduction of DVHs, correlated with late toxicity. Conclusions: Postal questionnaire was effective for collection of patient-assessed late toxicity data. The incidence of late toxicity was low, with a lack of correlation to dosimetric parameters. We attribute this to the use of conformal techniques and daily image guidance.

Skala, Marketa [Department of Radiation Oncology, Princess Margaret Hospital and University of Toronto, Toronto, ON (Canada); Rosewall, Tara [Department of Radiation Therapy, Princess Margaret Hospital and University of Toronto, Toronto, ON (Canada); Dawson, Laura [Department of Radiation Oncology, Princess Margaret Hospital and University of Toronto, Toronto, ON (Canada); Divanbeigi, Lorella [Department of Radiation Therapy, Princess Margaret Hospital and University of Toronto, Toronto, ON (Canada); Lockwood, Gina [Department of Biostatistics, Princess Margaret Hospital and University of Toronto, Toronto, ON (Canada); Thomas, Christopher [Department of Medical Physics, Princess Margaret Hospital and University of Toronto, Toronto, ON (Canada); Crook, Juanita [Department of Radiation Oncology, Princess Margaret Hospital and University of Toronto, Toronto, ON (Canada); Chung, Peter [Department of Radiation Oncology, Princess Margaret Hospital and University of Toronto, Toronto, ON (Canada); Warde, Padraig [Department of Radiation Oncology, Princess Margaret Hospital and University of Toronto, Toronto, ON (Canada); Catton, Charles [Department of Radiation Oncology, Princess Margaret Hospital and University of Toronto, Toronto, ON (Canada)]. E-mail: charles.catton@rmp.uhn.on.ca

2007-07-01

214

Qualification of electronic components and systems in a LHC Tunnel Radiation Environment  

E-print Network

Around 10.200 electronic crates will be installed in the LHC underground areas of which some 4.200 will be connected to the machine control network. Some of the electronic equipment will be housed under the cryostats of the main dipoles inside the tunnel. Other equipment will be placed alongside the tunnel, in the alcoves or in galleries parallel to the machine. In the regular arcs and in the dispersion suppressors areas the expected annual dose is low, i.e. only a few Gy/y. However, preliminary radiation tests showed that electronic equipment fails even at such low dose rates. Since radiation qualification of all tunnel electronics is essential in order to guarantee its reliable operation over the lifetime of the machine, a LHC radiation test facility was commissioned in the North Experimental Area of the SPS accelerator. This paper presents the simulation study concerning the radiation environment of the LHC Radiation Test Facility and gives an overview of the various underground electronic systems as they ...

Rausch, R; Wijnands, Thijs

2002-01-01

215

SRS conversion of XeCl laser radiation into shifted Stokes components  

SciTech Connect

An experimental study and a theoretical simulation were made of stimulated Raman scattering (SRS) conversion into shifted components. It was found that there were optimal values of the pressure and focal distance for conversion into the first 'blue' satellite of the first Stokes component. A study was made of the spatial and temporal dynamics of SRS conversion, which took into account generation of the shifted components. It was demonstrated theoretically and experimentally that the satellite intensity could be enhanced significantly by additional electron-collision excitation of the vibrational levels in the conversion medium or by the application of pairs of pump pulses. The maximum efficiency of conversion to the first 'blue' satellite of the first Stokes component was 10% and the satellite intensity reached one-third of the intensity of the main Stokes line. (nonlinear optical phenomena and devices)

Kaul', V B; Kunts, S E; Mel'chenko, S V [Institute of High Current Electronics, Siberian Branch, Russian Academy of Sciences, Tomsk (Russian Federation)

1998-01-31

216

Evaluation of 20-min and Annual Radiation Budget Components and Cloudiness in a Mountainous Valley  

Microsoft Academic Search

Logan, Utah (USA) is among cities located in the mountainous valley in the western portion of Rocky Mountains in North America. It is the county seat of Cache Valley, a metropolitan area with a population of about 100,000. The valley had the polluted air in the USA during January 2004. To evaluate the daily and annual radiation budget and cloudiness

E. Malek

2007-01-01

217

Radiation Effects and Hardening Techniques for Spacecraft Microelectronics  

NASA Astrophysics Data System (ADS)

The natural radiation from the Van Allen belts, solar flares, and cosmic rays found outside of the protection of the earth's atmosphere can produce deleterious effects on microelectronics used in space systems. Historically civil space agencies and the commercial satellite industry have been able to utilize components produced in special radiation hardened fabrication process foundries that were developed during the 1970s and 1980s under sponsorship of the Departments of Defense (DoD) and Energy (DoE). In the post--cold war world the DoD and DoE push to advance the rad--hard processes has waned. Today the available rad--hard components lag two-plus technology node generations behind state- of-the-art commercial technologies. As a result space craft designers face a large performance gap when trying to utilize available rad--hard components. Compounding the performance gap problems, rad--hard components are becoming increasingly harder to get. Faced with the economic pitfalls associated with low demand versus the ever increasing investment required for integrated circuit manufacturing equipment most sources of rad--hard parts have simply exited this market in recent years, leaving only two domestic US suppliers of digital rad--hard components. This paper summarizes the radiation induced mechanisms that can cause digital microelectronics to fail in space, techniques that can be applied to mitigate these failure mechanisms, and ground based testing used to validate radiation hardness/tolerance. The radiation hardening techniques can be broken down into two classes, Hardness By Process (HBP) and Hardness By Design (HBD). Fortunately many HBD techniques can be applied to commercial fabrication processes providing space craft designer with radiation tolerant Application Specific Integrated Circuits (ASICs) that can bridge the performance gap between the special HBP foundries and the commercial state-of-the-art performance.

Gambles, J. W.; Maki, G. K.

2002-01-01

218

Experimental shielding evaluation of the radiation protection provided by the structurally significant components of residential structures.  

PubMed

The human health and environmental effects following a postulated accidental release of radioactive material to the environment have been a public and regulatory concern since the early development of nuclear technology. These postulated releases have been researched extensively to better understand the potential risks for accident mitigation and emergency planning purposes. The objective of this investigation is to provide an updated technical basis for contemporary building shielding factors for the US housing stock. Building shielding factors quantify the protection from ionising radiation provided by a certain building type. Much of the current data used to determine the quality of shielding around nuclear facilities and urban environments is based on simplistic point-kernel calculations for 1950s era suburbia and is no longer applicable to the densely populated urban environments realised today. To analyse a building's radiation shielding properties, the ideal approach would be to subject a variety of building types to various radioactive sources and measure the radiation levels in and around the building. While this is not entirely practicable, this research analyses the shielding effectiveness of ten structurally significant US housing-stock models (walls and roofs) important for shielding against ionising radiation. The experimental data are used to benchmark computational models to calculate the shielding effectiveness of various building configurations under investigation from two types of realistic environmental source terms. Various combinations of these ten shielding models can be used to develop full-scale computational housing-unit models for building shielding factor calculations representing 69.6 million housing units (61.3%) in the United States. Results produced in this investigation provide a comparison between theory and experiment behind building shielding factor methodology. PMID:24487195

Dickson, E D; Hamby, D M

2014-03-01

219

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 ...

220

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

PubMed

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

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

2008-10-01

221

Diagnostic components in harsh radiation environments: Possible overlap in R and D requirements of inertial confinement and magnetic fusion systems  

SciTech Connect

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

Bourgade, J. L.; Leray, J. L.; Baggio, J.; Girard, S. [CEA/DAM Ile de France, Bruyeres le Chatel, 91297 Arpajon Cedex (France); Costley, A. E.; Dentan, M.; Bertalot, L.; Vayakis, G. [ITER Organization, Cadarache, 13108 St Paul-Les-Durance (France); Reichle, R.; Hutter, T. [Association EURATOM-CEA, DSM/IRFM, CEA-Cadarache, 13108 St. Paul-lez-Durance (France); Hodgson, E. R.; Morono, A. [EURATOM/CIEMAT Fusion Association, 28040 Madrid (Spain); Hsing, W.; Eder, D.; Moran, M. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Glebov, V.; Shmayda, W.; Sangster, T. C.; Stoeckl, C.; Pien, G. [Laboratory for Laser Energetics (LLE), University of Rochester, 250E. River Rd, Rochester, New York 14623 (United States)] (and others)

2008-10-15

222

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

NASA Technical Reports Server (NTRS)

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.

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

1994-01-01

223

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

NASA Astrophysics Data System (ADS)

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.

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

2013-05-01

224

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

SciTech Connect

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.

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

2013-05-10

225

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

SciTech Connect

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.

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

226

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

NASA Astrophysics Data System (ADS)

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.

Goren, Tom; Rosenfeld, Daniel

2014-03-01

227

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

E-print Network

memory machines. ACKNOWLEDGMENTS I would like to thank my adviser, Lawrence Rauchwerger for the critical help he has provided during the duration of my master's work. I also thank Nancy Amato, Marvin Adams, and the rest of the ASCI group at Texas ASM... Hewlett Packard V-Class server at Texas AkM University. This machine is a 16-processor ccUMA SMP running 200 MHz PA-RISC processors. Our implementation of ModifiedDCSC is optimized for the detection and elim- ination of strongly connected components...

McLendon, William Clarence

2012-06-07

228

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

NASA Astrophysics Data System (ADS)

The mineralogy of desert dust is important due to its effect on radiation, clouds and biogeochemical cycling of trace nutrients. This study presents the simulation of dust radiative forcing as a function of both mineral composition and size at the global scale using mineral soil maps for estimating emissions. Externally mixed mineral aerosols in the bulk aerosol module in the Community Atmosphere Model version 4 (CAM4) and internally mixed mineral aerosols in the modal aerosol module in the Community Atmosphere Model version 5.1 (CAM5) embedded in the Community Earth System Model version 1.0.5 (CESM) are speciated into common mineral components in place of total dust. The simulations with mineralogy are compared to available observations of mineral atmospheric distribution and deposition along with observations of clear-sky radiative forcing efficiency. Based on these simulations, we estimate the all-sky direct radiative forcing at the top of the atmosphere as +0.05 W m-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 +0.17 W m-2) and of dust with optimized optical properties, wet scavenging and particle size distribution in CAM4 and CAM5, -0.05 and -0.17 W m-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.

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

2014-07-01

229

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

NASA Technical Reports Server (NTRS)

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.

Mcgarrity, J. M.

1980-01-01

230

Polaradiometric pyrometer in which the parallel and perpendicular components of radiation reflected from an unpolarized light source are equalized with the thermal radiation emitted from a measured object to determine its true temperature  

NASA Technical Reports Server (NTRS)

A radiation pyrometer for measuring the true temperature of a body is provided by detecting and measuring thermal radiation from the body based on the principle that the effects of angular emission I(sub 1) and reflection I(sub 2) on the polarization states p and s of radiation are complementary such that upon detecting the combined partial polarization state components I(sub p) =I(sub 1p) + I(sub 2p) and I(sub s)=I(sub 1s) + I(sub 2s) and adjusting the intensity of the variable radiation source of the reflected radiation I(sub 2) until the combined partial radiation components I(sub p) and I(sub s) are equal, the effects of emissivity as well as diffusivity of the surface of the body are eliminated, thus obviating the need for any post processing of brightness temperature data.

Abtahi, Ali A. (Inventor)

1995-01-01

231

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

SciTech Connect

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

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

2008-05-08

232

Hard Metal Disease  

PubMed Central

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

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

1962-01-01

233

Coherent terahertz radiation from high-harmonic component of modulated free-electron beam in a tapered two-asymmetric grating structure  

SciTech Connect

Based on the mechanism of incoherent diffraction radiation excited by an electron bunch in a waveguide with periodic structure, this paper presents the concept of coherent terahertz (THz) radiation from the high-harmonic component of a modulated free-electron beam in a tapered two-asymmetric grating structure. The results show that in this mechanism 0.43 THz radiation can be generated with 10 A/cm{sup 2} current density, and the efficiency can reach 0.5%. Because of the low required current density and relative high efficiency, this concept shows the application potential for electron-beam-driven terahertz sources.

Zhang Yaxin; Zhou Yucong; Dong Liang; Liu Shenggang [Terahertz Science and Technology Research Center, University of Electronic Science and Technology of China, Chengdu 610054 (China)

2012-09-17

234

Enhancement of the aerosol direct radiative effect by semi-volatile aerosol components: airborne measurements in North-Western Europe  

NASA Astrophysics Data System (ADS)

A case study of atmospheric aerosol measurements exploring the impact of the vertical distribution of aerosol chemical composition upon the radiative budget in North-Western Europe is presented. Sub-micron aerosol chemical composition was measured by an Aerodyne Aerosol Mass Spectrometer (AMS) on both an airborne platform and a ground-based site at Cabauw in the Netherlands. The examined period in May 2008 was characterised by enhanced pollution loadings in North-Western Europe and was dominated by ammonium nitrate and Organic Matter (OM). Both ammonium nitrate and OM were observed to increase with altitude in the atmospheric boundary layer. This is primarily attributed to partitioning of semi-volatile gas phase species to the particle phase at reduced temperature and enhanced relative humidity. Increased ammonium nitrate concentrations in particular were found to strongly increase the ambient scattering potential of the aerosol burden, which was a consequence of the large amount of associated water as well as the enhanced mass. During particularly polluted conditions, increases in aerosol optical depth of 50-100% were estimated to occur due to the observed increase in secondary aerosol mass and associated water uptake. Furthermore, the single scattering albedo was also shown to increase with height in the boundary layer. These enhancements combined to increase the negative direct aerosol radiative forcing by close to a factor of two at the median percentile level. Such increases have major ramifications for regional climate predictions as semi-volatile components are often not included in aerosol models. The results presented here provide an ideal opportunity to test regional and global representations of both the aerosol vertical distribution and subsequent impacts in North-Western Europe. North-Western Europe can be viewed as an analogue for the possible future air quality over other polluted regions of the Northern Hemisphere, where substantial reductions in sulphur dioxide emissions have yet to occur. Anticipated reductions in sulphur dioxide in polluted regions will result in an increase in the availability of ammonia to form ammonium nitrate as opposed to ammonium sulphate. This will be most important where intensive agricultural practises occur. Our observations over North-Western Europe, a region where sulphur dioxide emissions have already been reduced, indicate that failure to include the semi-volatile behaviour of ammonium nitrate will result in significant errors in predicted aerosol direct radiative forcing. Such errors will be particularly significant on regional scales.

Morgan, W. T.; Allan, J. D.; Bower, K. N.; Esselborn, M.; Harris, B.; Henzing, J. S.; Highwood, E. J.; Kiendler-Scharr, A.; McMeeking, G. R.; Mensah, A. A.; Northway, M. J.; Osborne, S.; Williams, P. I.; Krejci, R.; Coe, H.

2010-04-01

235

Enhancement of the aerosol direct radiative effect by semi-volatile aerosol components: airborne measurements in North-Western Europe  

NASA Astrophysics Data System (ADS)

A case study of atmospheric aerosol measurements exploring the impact of the vertical distribution of aerosol chemical composition upon the radiative budget in North-Western Europe is presented. Sub-micron aerosol chemical composition was measured by an Aerodyne Aerosol Mass Spectrometer (AMS) on both an airborne platform and a ground-based site at Cabauw in the Netherlands. The examined period in May 2008 was characterised by enhanced pollution loadings in North-Western Europe and was dominated by ammonium nitrate and Organic Matter (OM). Both ammonium nitrate and OM were observed to increase with altitude in the atmospheric boundary layer. This is primarily attributed to partitioning of semi-volatile gas phase species to the particle phase at reduced temperature and enhanced relative humidity. Increased ammonium nitrate concentrations in particular were found to strongly increase the ambient scattering potential of the aerosol burden, which was a consequence of the large amount of associated water as well as the enhanced mass. During particularly polluted conditions, increases in aerosol optical depth of 50-100% were estimated to occur due to the observed increase in secondary aerosol mass and associated water uptake. Furthermore, the single scattering albedo was also shown to increase with height in the boundary layer. These enhancements combined to increase the negative direct aerosol radiative forcing by close to a factor of two at the median percentile level. Such increases have major ramifications for regional climate predictions as semi-volatile components are often not included in aerosol models. The results presented here provide an ideal opportunity to test regional and global representations of both the aerosol vertical distribution and subsequent impacts in North-Western Europe. North-Western Europe can be viewed as an analogue for the possible future air quality over other polluted regions of the Northern Hemisphere, where substantial reductions in sulphur dioxide emissions have yet to occur. Anticipated reductions in sulphur dioxide in polluted regions will result in an increase in the availability of ammonia to form ammonium nitrate as opposed to ammonium sulphate. This will be most important where intensive agricultural practises occur. Our observations over North-Western Europe, a region where sulphur dioxide emissions have already been reduced, indicate that failure to include the semi-volatile behaviour of ammonium nitrate will result in significant errors in predicted aerosol direct radiative forcing. Such errors will be particularly significant on regional scales.

Morgan, W. T.; Allan, J. D.; Bower, K. N.; Esselborn, M.; Harris, B.; Henzing, J. S.; Highwood, E. J.; Kiendler-Scharr, A.; McMeeking, G. R.; Mensah, A. A.; Northway, M. J.; Osborne, S.; Williams, P. I.; Krejci, R.; Coe, H.

2010-09-01

236

MIL-STD-1553 VLSI components  

NASA Astrophysics Data System (ADS)

The performance, physical and electrical characteristics of novel VLSI components which will support all MIL-STD-1553 terminals are described. A transceiver, protocol, and computer interface set of chips supports remote terminal unit, bus controller, and bus monitor modes of operation. A discussion of these VLSI components is given, and their special features are explored. These features include size and packaging options, radiation hardness, power, and reliability considerations. The special capabilities of these devices are highlighted, along with programming options that facilitate a broad array of applications.

Friedman, Steven N.

237

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

SciTech Connect

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.

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

238

Considerations for IC and Component Selection for Space Systems  

NASA Technical Reports Server (NTRS)

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

LaBel, Kenneth A.; Cohn, Lewis M.

2008-01-01

239

Wear of hard materials by hard particles  

SciTech Connect

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.

Hawk, Jeffrey A.

2003-10-01

240

Rad-Hard/HI-REL FPGA  

NASA Technical Reports Server (NTRS)

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.

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

1997-01-01

241

Electromagnetic Analysis of Synchronous and Asynchronous Circuits using Hard  

E-print Network

Electromagnetic Analysis of Synchronous and Asynchronous Circuits using Hard Disc Heads Theo and electromagnetic analysis (EMA) · Construction of different sensors for EMA · Differential EMA on synchronous the magnetic field component ­ Inductive hard disc head (circa 1990) ­ Giant magnetoresistive hard disc head

Moore, Simon

242

Analysis of ITO/Mg:GaN interfaces by synchrotron radiation hard X-ray photoemission spectroscopy and their electrical characteristics  

NASA Astrophysics Data System (ADS)

Interfacial chemical states and Schottky barrier heights (SBHs) for indium tin oxide (ITO) electrodes on Mg:GaN films have been investigated by high-resolution hard X-ray photoemission spectroscopy (HX-PES), and have been correlated with electrical properties. HX-PES has revealed that the large downward band bending of 2.6 eV was drastically reduced by ITO deposition and annealing, resulting in low SBH of 0.2 eV which is well correlated with good ohmic contact. Improvements of electrical properties can be attributed to the combination of (1) the interfacial layer with large work function, (2) the ordered interfacial dipole layer and (3) activation by ITO catalytic effect.

Toyoshima, Y.; Horiba, K.; Oshima, M.; Ohta, J.; Fujioka, H.; Miki, H.; Ueda, S.; Yamashita, Y.; Yoshikawa, H.; Kobayashi, K.

243

Hardness testing. 2nd edition  

SciTech Connect

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.

Chandler, H. [ed.

1999-07-01

244

XIV International Conference on Atmospheric Electricity, August 08-12, 2011, Rio de Janeiro, Brazil Understanding Electron Run-away and Hard Radiation  

E-print Network

XIV International Conference on Atmospheric Electricity, August 08-12, 2011, Rio de Janeiro, Brazil: Terrestrial gamma-ray flashes are observed above thunderclouds. Energetic radiation is also reported from lightning leaders approaching ground, and it is measured during the initial streamer-leader phase of meter

Ebert, Ute

245

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

PubMed Central

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

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

2013-01-01

246

RAD hard PROM design study  

NASA Technical Reports Server (NTRS)

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.

1981-01-01

247

Long-term changes in net radiation and its components above a pine forest and a grass surface in Germany  

NASA Astrophysics Data System (ADS)

Long-term measurements (1974-1993 and 1996, respectively) of the net radiation (Q), global radiation (G), reflected global radiation (R), long-wave atmospheric radiation (A) and thermal radiation (E) of a pine forest in Southern Germany (index p) and of a grass surface in Northern Germany (index g) are compared. The influence of changes in surface properties is discussed. There are, in the case of the pine stand, forest growth and forest management and in the case of the grass surface, the shifting of the site from a climatic garden to a horizontal roof. Both series of radiant fluxes are analyzed with respect to the influences of the weather (cloudiness, heat advection). To eliminate the different influence of the solar radiation of the two sites, it is necessary to normalize by means of the global radiation G, yielding the radiation efficiency Q/G, the albedo R/G=? and the normalized long-wave net radiation (A+E)/G. Furthermore, the long-term mean values and the long-term trend of yearly mean values are discussed and, moreover, a comparison is made of individual monthly values. Qp is twice as large as Qg. The reason for this is the higher values of G and A above the pine forest and half values of ?p compared to ?g. Ep is only a little greater than Eg. The time series of the radiation fluxes show the following trends: Qp declines continuously despite a slight increase of Gp. This is mainly due to the long-wave radiation fluxes. The net radiation of the grass surface Qg shows noticeably lower values after the merging of the site. This phenomenon is also dominated by the long-wave radiation processes. Although the properties of both site surfaces alter, Ep and Eg remain relatively stable. Ap and Ag show a remarkable decrease however. The reason for this is to be found in a modification of the heat advection, showing a more pronounced impact on the more continentally exposed site (pine forest). Compared to ?g, ?p shows only a small variability. The changes of ?p can be easily explained as resulting from the influence on the albedo of alterations in cloudiness and the changes in the water storage in stand and soil produced by varying weather conditions. The influence of the forest management is only small and short-termed. ?g reacted with a leap on site merging, followed by a continuous drop. The drop of the grass surface albedo ?g on top of the observatory is probably related to the gradual development of the newly sown lawn there and the resultant change in the specific hydrological balance of the soil. A decreasing radiation efficiency Q/G at both sites is observed, which is principally due to an increase in -(A+E)/G. The investigation discovered changes in the long-wave radiation processes. Its influence in Q should lead to more attention to the long-wave radiation processes in routine monitoring of radiation.

Kessler, A.; Jaeger, L.

1999-02-01

248

Overview: Hard Rock Penetration  

SciTech Connect

The Hard Rock Penetration program is developing technology to reduce the costs of drilling and completing geothermal wells. Current projects include: lost circulation control, rock penetration mechanics, instrumentation, and industry/DOE cost shared projects of the Geothermal Drilling organization. Last year, a number of accomplishments were achieved in each of these areas. A new flow meter being developed to accurately measure drilling fluid outflow was tested extensively during Long Valley drilling. Results show that this meter is rugged, reliable, and can provide useful measurements of small differences in fluid inflow and outflow rates. By providing early indications of fluid gain or loss, improved control of blow-out and lost circulation problems during geothermal drilling can be expected. In the area of downhole tools for lost circulation control, the concept of a downhole injector for injecting a two-component, fast-setting cementitious mud was developed. DOE filed a patent application for this concept during FY 91. The design criteria for a high-temperature potassium, uranium, thorium logging tool featuring a downhole data storage computer were established, and a request for proposals was submitted to tool development companies. The fundamental theory of acoustic telemetry in drill strings was significantly advanced through field experimentation and analysis. A new understanding of energy loss mechanisms was developed.

Dunn, J.C.

1992-08-01

249

How Hard is Chocolate?  

NSDL National Science Digital Library

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.

2007-12-20

250

Ultrasonic material hardness depth measurement  

DOEpatents

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.

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

1997-07-08

251

Radiation  

Cancer.gov

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

252

Radiation Hardness Studies of InGaAs and Si Photodiodes at 30, 52, & 98 MeV and Fluences to 5 × 1011 PROTONS/CM2  

NASA Astrophysics Data System (ADS)

Here we report the results of an investigation into the effects of ionizing radiation on commercial off-the-shelf InGaAs and Si photodiodes. The photodiodes were exposed to 30, 52, and 98 MeV protons with fluences ranging from 108 - 5 × 1011 protons/cm2 at the Indiana University Cyclotron Facility. We tested the photodiodes for changes to their dark current and their relative responsivity as a function of wavelength. The Si photodiodes showed increasing damage to their responsivity with increasing fluence; the InGaAs photodiodes showed significantly increased dark current as the fluence increased. In addition, we monitored the absolute responsivity of the InGaAs photodiodes over their entire bandpass. Our measurements showed no evidence for broadband degradation or graying of the response at the fluences tested. All measurements in this investigation were made relative to detectors traceable to NIST standards.

Baptista, B. J.; Mufson, S. L.

2013-09-01

253

Vulnerability and behavioral response to ultraviolet radiation in the components of a foliar mite prey-predator system  

NASA Astrophysics Data System (ADS)

Ambient ultraviolet-B (UVB) radiation impacts plant-dwelling arthropods including herbivorous and predatory mites. However, the effects of UVB on prey-predator systems, such as that between the herbivorous spider mite and predatory phytoseiid mite, are poorly understood. A comparative study was conducted to determine the vulnerability and behavioral responses of these mites to ultraviolet (UV) radiation. First, we analyzed dose-response (cumulative irradiance-mortality) curves for the eggs of phytoseiid mites ( Neoseiulus californicus, Neoseiulus womersleyi, and Phytoseiulus persimilis) and the spider mite ( Tetranychus urticae) to UVB radiation from a UV lamp. This indicated that the phytoseiid mites were more vulnerable than the spider mite, although P. persimilis was slightly more tolerant than the other two phytoseiid mites. Second, we compared the avoidance behavior of adult female N. californicus and two spider mite species ( T. urticae, a lower leaf surface user; Panonychus citri, an upper leaf surface user) in response to solar UV and visible light. N. californicus actively avoided both types of radiation, whereas P. citri showed only minimal avoidance behavior. T. urticae actively avoided UV as well as N. californicus but exhibited a slow response to visible light as well as P. citri. Such variation in vulnerability and avoidance behavior accounts for differences in the species adaptations to solar UVB radiation. This may be the primary factor determining habitat use among these mites on host plant leaves, subsequently affecting accessibility by predators and also intraguild competition.

Tachi, Fuyuki; Osakabe, Masahiro

2012-12-01

254

Vulnerability and behavioral response to ultraviolet radiation in the components of a foliar mite prey-predator system.  

PubMed

Ambient ultraviolet-B (UVB) radiation impacts plant-dwelling arthropods including herbivorous and predatory mites. However, the effects of UVB on prey-predator systems, such as that between the herbivorous spider mite and predatory phytoseiid mite, are poorly understood. A comparative study was conducted to determine the vulnerability and behavioral responses of these mites to ultraviolet (UV) radiation. First, we analyzed dose-response (cumulative irradiance-mortality) curves for the eggs of phytoseiid mites (Neoseiulus californicus, Neoseiulus womersleyi, and Phytoseiulus persimilis) and the spider mite (Tetranychus urticae) to UVB radiation from a UV lamp. This indicated that the phytoseiid mites were more vulnerable than the spider mite, although P. persimilis was slightly more tolerant than the other two phytoseiid mites. Second, we compared the avoidance behavior of adult female N. californicus and two spider mite species (T. urticae, a lower leaf surface user; Panonychus citri, an upper leaf surface user) in response to solar UV and visible light. N. californicus actively avoided both types of radiation, whereas P. citri showed only minimal avoidance behavior. T. urticae actively avoided UV as well as N. californicus but exhibited a slow response to visible light as well as P. citri. Such variation in vulnerability and avoidance behavior accounts for differences in the species adaptations to solar UVB radiation. This may be the primary factor determining habitat use among these mites on host plant leaves, subsequently affecting accessibility by predators and also intraguild competition. PMID:23093097

Tachi, Fuyuki; Osakabe, Masahiro

2012-12-01

255

Session: Hard Rock Penetration  

SciTech Connect

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.

Tennyson, George P. Jr.; Dunn, James C.; Drumheller, Douglas S.; Glowka, David A.; Lysne, Peter

1992-01-01

256

Hardness Tester for Polyur  

NASA Technical Reports Server (NTRS)

Rubber-hardness tester modified for use on rigid polyurethane foam. Provides objective basis for evaluation of improvements in foam manufacturing and inspection. Typical acceptance criterion requires minimum hardness reading of 80 on modified tester. With adequate correlation tests, modified tester used to measure indirectly tensile and compressive strengths of foam.

Hauser, D. L.; Buras, D. F.; Corbin, J. M.

1987-01-01

257

Memory Hard Drive Peripherals  

E-print Network

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

Stojmenovic, Ivan

258

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

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

259

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

E-print Network

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

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

2014-01-01

260

HARD BREMSSTRAHLUNG PHOTONS FROM GRAVITON EXCHANGE  

E-print Network

HARD BREMSSTRAHLUNG PHOTONS FROM GRAVITON EXCHANGE #3; LC-TH-2004-015 T. BUANES, E.W. DVERGSNES Abstract We review photon Bremsstrahlung in extra-dimensional models with massive gravitons. The photon spectrum is harder than in the Standard Model. In the RS scenario, radiative return to gravitons below

261

Passive exposure of Earth radiation budget experiment components. LDEF experiment AO-147: Post-flight examinations and tests  

NASA Technical Reports Server (NTRS)

The flight spare sensors of the Earth Radiation Budget (ERB) experiment of the Nimbus 6 and 7 missions were flown aboard the LDEF. The preliminary post retrieval examination and test results are presented here for the sensor windows and filters, the thermopile sensors and a cavity radiometer.

Hickey, John R.

1992-01-01

262

The Diffuse Galactic gamma Radiation: The Compton Contribution and Component Separation by Energy Interval and Galactic Coordinates.  

National Technical Information Service (NTIS)

The radiation to be expected from cosmic ray interactions with matter and photons was examined. Particular emphasis is placed on the Compton emission. Both the photon density in and near the visible region and that in the region are deduced from the estim...

D. A. Kniffen, C. E. Fichtel

1981-01-01

263

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

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

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

2014-01-01

264

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

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

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

2014-01-01

265

Development of a plasma panel radiation detector  

E-print Network

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.

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

266

On the quality of the hardness kernel and the Fukui function to evaluate the global hardness.  

PubMed

An approximated hardness kernel, which includes the second derivative with respect to the density of the kinetic energy, the electron-electron coulomb repulsion, and the exchange density functionals, has been tested for the calculation of the global hardness. The results obtained for a series of 40 cations and neutral systems and 16 anions represent in most cases an improvement of the results obtained using the HOMO-LUMO gap approach and indicate the viability of this approach to evaluate global hardness. In addition, the relevance of the Fukui function approximation and the role of the three components of the hardness kernel in the evaluation of the global hardness have been analyzed. PMID:17186480

Torrent-Sucarrat, Miquel; Salvador, Pedro; Geerlings, Paul; Solà, Miquel

2007-01-30

267

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

NASA Technical Reports Server (NTRS)

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.

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

1976-01-01

268

Extraction of chemical information of suspensions using radiative transfer theory to remove multiple scattering effects: application to a model two-component system.  

PubMed

An approach for removing multiple light scattering effects using the radiative transfer theory (RTE) in order to improve the performance of multivariate calibration models is proposed. This approach is then applied to the problem of building calibration models for predicting the concentration of a scattering (particulate) component. Application of this approach to a simulated four component system showed that it will lead to calibration models which perform appreciably better than when empirically scatter corrected measurements of diffuse transmittance (T(d)) or reflectance (R(d)) are used. The validity of the method was also tested experimentally using a two-component (polystyrene-water) system. While the proposed method led to a model that performed better than the one built using R(d), its performance was worse compared to when T(d) measurements were used. Analysis indicates that this is because the model built using T(d) benefits from the strong secondary correlation between particle concentration and path length traveled by the photons which occurs due to the system containing only two components. On the other hand, the model arising from the proposed methodology uses essentially only the chemical (polystyrene) signal. Thus, this approach can be expected to work better in multicomponent systems where the path length correlation would not exist. PMID:19694478

Steponavicius, Raimundas; Thennadil, Suresh N

2009-09-15

269

A study of hard X-ray associated meter-decameter bursts observed on December 19, 1979  

NASA Technical Reports Server (NTRS)

The results of a study of the relationship of a complex meter-decameter wavelength radio burst observed with the Clark Lake E-W and N-S interferometers, with a hard X-ray burst observed with the X-ray spectrometer aboard ISEE-3 are presented. The radio burst consisted of several type III's, reverse drift type III's, a U burst, and type II and type IV bursts. The X-ray emission was also complex. The radio as well as hard X-ray emissions were observed before the flash phase of the flare; they were not always associated and it is conjectured that this may constitute evidence for acceleration of electrons high in the corona. On the other hand, all components of the reverse drift burst were associated with hard X-ray subpeaks, indicating multiple injection of electron beams along field lines with different density gradients. While the type II burst appeared to be related to the hard X-ray burst, a detailed correspondence between individual features of the radio and hard X-ray burst emissions could not be found. The type IV burst started after all hard X-ray emissions ceased. Its source appeared to be a magnetic arch, presumably containing energetic electrons reponsible for the gyrosynchrotron radiation of type IV.

Kundu, M. R.; Gergely, T. E.; Kane, S. R.; Sawant, H. S.

1986-01-01

270

Dynamic hardness testing of metallic materials  

Microsoft Academic Search

A method of hardness testing is presented based on the measurement of the kinetic energy components of impact and rebound of the testing body. The testing instrument consists of an impact device and an electronic indicator device. The impact and rebound velocities are measured in a contactless manner by means of an electromagnetic transmitter and the result from dividing the

D. Leeb

1979-01-01

271

Radiators  

SciTech Connect

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, the spigot carrying an O-ring seal and either latching fingers or a resilient latching circlip.

Webster, D. M.

1985-07-30

272

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

NASA Astrophysics Data System (ADS)

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

Kovalev, Valerii I.

1995-11-01

273

AMORPHOUS ALLOY SURFACE COATINGS FOR HARD CHROMIUM REPLACEMENT - PHASE I  

EPA Science Inventory

Hard chromium coatings (0.25 to10 mil thick) are used extensively for imparting wear and erosion resistance to components in both industrial and military applications. The most common means of depositing hard chromium has been through the use of chromic acid baths containing ...

274

Statistical Modeling for Radiation Hardness Assurance  

NASA Technical Reports Server (NTRS)

We cover the models and statistics associated with single event effects (and total ionizing dose), why we need them, and how to use them: What models are used, what errors exist in real test data, and what the model allows us to say about the DUT will be discussed. In addition, how to use other sources of data such as historical, heritage, and similar part and how to apply experience, physics, and expert opinion to the analysis will be covered. Also included will be concepts of Bayesian statistics, data fitting, and bounding rates.

Ladbury, Raymond L.

2014-01-01

275

A Fiber Detector Radiation Hardness Test  

E-print Network

An intense 146 MeV/c pion beam was stopped inside a scintillating fiber detector made out of 12 planes with 16 pixels each, where every pixel consists out of 8 times 8 scintillating fibers of 500 mkm diameter dense packed. The detector was irradiated for 52 hours to more than 1 Mrad at its center. Before and directly after the irradiation the detector has been exposed to a particle beam to compare the corresponding light output. This study was continued during the following three months using cosmic rays. No damage was found taking into account the measurement errors of 5-10 %. In contrast a 9 cm deep lucite degrader became irreversibly non-transparent in the irradiation region.

J. Baehr; R. Nahnhauer; S. Nerreter; R. Shanidze

1999-07-13

276

Hard superconducting nitrides  

PubMed Central

Detailed study of the equation of state, elasticity, and hardness of selected superconducting transition-metal nitrides reveals interesting correlations among their physical properties. Both the bulk modulus and Vickers hardness are found to decrease with increasing zero-pressure volume in NbN, HfN, and ZrN. The computed elastic constants from first principles satisfy c11 > c12 > c44 for NbN, but c11 > c44 > c12 for HfN and ZrN, which are in good agreement with the neutron scattering data. The cubic ?-NbN superconducting phase possesses a bulk modulus of 348 GPa, comparable to that of cubic boron nitride, and a Vickers hardness of 20 GPa, which is close to sapphire. Theoretical calculations for NbN show that all elastic moduli increase monotonically with increasing pressure. These results suggest technological applications of such materials in extreme environments. PMID:15728352

Chen, Xiao-Jia; Struzhkin, Viktor V.; Wu, Zhigang; Somayazulu, Maddury; Qian, Jiang; Kung, Simon; Christensen, Axel N?rlund; Zhao, Yusheng; Cohen, Ronald E.; Mao, Ho-kwang; Hemley, Russell J.

2005-01-01

277

CSI: Hard Drive  

ERIC Educational Resources Information Center

Acting on information from students who reported seeing a classmate looking at inappropriate material on a school computer, school officials used forensics software to plunge the depths of the PC's hard drive, searching for evidence of improper activity. Images were found in a deleted Internet Explorer cache as well as deleted file space.…

Sturgeon, Julie

2008-01-01

278

Generating Hard Satisfiability Problems  

Microsoft Academic Search

We report results from large-scale experiments in satisfiability testing. As has been observed by others, testing the satisfiability of random formulas often appears surprisingly easy. Here we show that by using the right distribution of instances, and appropriate parameter valu es, it is possible to generate random formulas that are hard, that is, for which satisfiability testing is quite difficult.

Bart Selman; David G. Mitchell; Hector J. Levesque

1996-01-01

279

Hard Sphere Gas Model  

NSDL National Science Digital Library

The Ejs Hard Sphere Gas model displays a three-dimensional (ideal) gas made out of hard disks. Particles are initialized with a random speed and in a random direction and move with constant velocity until a collision occurs. You can modify this simulation if you have Ejs installed by right-clicking within the plot and selecting âOpen Ejs Modelâ from the pop-up menu item. Ejs Hard Sphere Gas model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_newton_HardShpereGas.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models for statistical mechanics are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Christian, Wolfgang

2008-07-06

280

Hardness vs Randomness  

Microsoft Academic Search

We present a simple ne wc onstruction of a pseudorandom bit generator ,b ased on the constant depth generators of (N). It stretches a short string of truly random bits into a long string that looks random to an ya lgorithm from a comple xity class C (eg P, NC, PSPACE, ... )u sing an arbitrary function that is hard

Noam Nisan; Avi Wigderson

1994-01-01

281

Work Hard. Be Nice  

ERIC Educational Resources Information Center

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,…

Mathews, Jay

2009-01-01

282

Hard Times Hit Schools  

ERIC Educational Resources Information Center

Hard-to-grasp dollar amounts are forcing real cuts in K-12 education at a time when the cost of fueling buses and providing school lunches is increasing and the demands of the federal No Child Left Behind Act still loom larger over states and districts. "One of the real challenges is to continue progress in light of the economy," said Gale Gaines,…

McNeil, Michele

2008-01-01

283

Ionizing radiation  

NASA Technical Reports Server (NTRS)

The penetrating ionizing space radiations are found to be extremely diverse in the energy range of both their particulate and their electromagnetic components. Radiation terms and measures and ionizing radiation classes and sources are presented. Whole body radiation effects are examined, including radiation intensity and rate effectiveness factors. Radiation effects on specific body systems, such as blood, skin, visual, and reproductive systems are also discussed.

Warren, S.; Grahn, D.

1973-01-01

284

Erosion testing of hard materials and coatings  

SciTech Connect

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).

Hawk, Jeffrey A.

2005-04-29

285

Nonvolatile Rad-Hard Holographic Memory  

NASA Technical Reports Server (NTRS)

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.

Chao, Tien-Hsin; Zhou, Han-Ying; Reyes, George; Dragoi, Danut; Hanna, Jay

2001-01-01

286

An interpretation of fluctuations in enzyme catalysis rate, spectral diffusion, and radiative component of lifetimes in terms of electric field fluctuations  

PubMed Central

Time-dependent fluctuations in the catalysis rate (?k(t)) observed in single-enzyme experiments were found in a particular study to have an autocorrelation function decaying on the same time scale as that of spectral diffusion ??0(t). To interpret this similarity, the present analysis focuses on a factor in enzyme catalysis, the local electrostatic interaction energy (E) at the active site and its effect on the activation free energy barrier. We consider the slow fluctuations of the electrostatic interaction energy (?E(t)) as a contributor to ?k(t) and relate the latter to ??0(t). The resulting relation between ?k(t) and ??0(t) is a dynamic analog of the solvatochromism used in interpreting solvent effects on organic reaction rates. The effect of the postulated ?E(t) on fluctuations in the radiative component (??r?1(t)) of the fluorescence decay of chromophores in proteins also is examined, and a relation between ??r?1(t) and ??0(t) is obtained. Experimental tests will determine whether the correlation functions for ?k(t), ??0(t), and ??r?1 are indeed similar for any enzyme. Measurements of dielectric dispersion, ?(?), for the enzyme discussed elsewhere will provide further insight into the correlation function for ?E(t). They also will determine whether fluctuations in the nonradiative component ?nr?1 of the lifetime decay has a different origin, fluctuations in distance for example. PMID:17911244

Prakash, Meher K.; Marcus, R. A.

2007-01-01

287

Hard Copy Market Overview  

NASA Astrophysics Data System (ADS)

A number of Color Hard Copy (CHC) market drivers are currently indicating strong growth in the use of CHC technologies for the business graphics marketplace. These market drivers relate to product, software, color monitors and color copiers. The use of color in business graphics allows more information to be relayed than is normally the case in a monochrome format. The communicative powers of full-color computer generated output in the business graphics application area will continue to induce end users to desire and require color in their future applications. A number of color hard copy technologies will be utilized in the presentation graphics arena. Thermal transfer, ink jet, photographic and electrophotographic technologies are all expected to be utilized in the business graphics presentation application area in the future. Since the end of 1984, the availability of color application software packages has grown significantly. Sales revenue generated by business graphics software is expected to grow at a compound annual growth rate of just over 40 percent to 1990. Increased availability of packages to allow the integration of text and graphics is expected. Currently, the latest versions of page description languages such as Postscript, Interpress and DDL all support color output. The use of color monitors will also drive the demand for color hard copy in the business graphics market place. The availability of higher resolution screens is allowing color monitors to be easily used for both text and graphics applications in the office environment. During 1987, the sales of color monitors are expected to surpass the sales of monochrome monitors. Another major color hard copy market driver will be the color copier. In order to take advantage of the communications power of computer generated color output, multiple copies are required for distribution. Product introductions of a new generation of color copiers is now underway with additional introductions expected during 1987. The color hard copy market continues to be in a state of constant change, typical of any immature market. However, much of the change is positive. During 1985, the color hard copy market generated 1.2 billion. By 1990, total market revenue is expected to exceed 5.5 billion. The business graphics CHC application area is expected to grow at a compound annual growth rate greater than 40 percent to 1990.

Testan, Peter R.

1987-04-01

288

Radiation-Tolerant DC-DC Converters  

NASA Technical Reports Server (NTRS)

A document discusses power converters suitable for space use that meet the DSCC MIL-PRF-38534 Appendix G radiation hardness level P classification. A method for qualifying commercially produced electronic parts for DC-DC converters per the Defense Supply Center Columbus (DSCC) radiation hardened assurance requirements was developed. Development and compliance testing of standard hybrid converters suitable for space use were completed for missions with total dose radiation requirements of up to 30 kRad. This innovation provides the same overall performance as standard hybrid converters, but includes assurance of radiation- tolerant design through components and design compliance testing. This availability of design-certified radiation-tolerant converters can significantly reduce total cost and delivery time for power converters for space applications that fit the appropriate DSCC classification (30 kRad).

Skutt, Glenn; Sable, Dan; Leslie, Leonard; Graham, Shawn

2012-01-01

289

Hard X-Ray Emission from the Galaxy Cluster A2256.  

PubMed

After the positive detection by BeppoSAX of hard X-ray radiation up to approximately 80 keV in the Coma Cluster spectrum, we present evidence for nonthermal emission from A2256 in excess of thermal emission at a 4.6 sigma confidence level. In addition to this power-law component, a second nonthermal component already detected by ASCA could be present in the X-ray spectrum of the cluster, which is not surprising given the complex radio morphology of the cluster central region. The spectral index of the hard tail detected by the Phoswich Detection System on board BeppoSAX is marginally consistent with that expected for the inverse Compton model. A value of approximately 0.05 µG is derived for the intracluster magnetic field of the extended radio emission in the northern regions of the cluster, while a higher value of approximately 0.5 µG could be present in the central radio halo, which is likely related to the hard tail detected by ASCA. PMID:10790058

Fusco-Femiano; Dal Fiume D; De Grandi S; Feretti; Giovannini; Grandi; Malizia; Matt; Molendi

2000-05-01

290

Hard X-Ray Emission from the Galaxy Cluster A2256  

NASA Astrophysics Data System (ADS)

After the positive detection by BeppoSAX of hard X-ray radiation up to ~80 keV in the Coma Cluster spectrum, we present evidence for nonthermal emission from A2256 in excess of thermal emission at a 4.6 ? confidence level. In addition to this power-law component, a second nonthermal component already detected by ASCA could be present in the X-ray spectrum of the cluster, which is not surprising given the complex radio morphology of the cluster central region. The spectral index of the hard tail detected by the Phoswich Detection System on board BeppoSAX is marginally consistent with that expected for the inverse Compton model. A value of ~0.05 ?G is derived for the intracluster magnetic field of the extended radio emission in the northern regions of the cluster, while a higher value of ~0.5 ?G could be present in the central radio halo, which is likely related to the hard tail detected by ASCA.

Fusco-Femiano, Roberto; Dal Fiume, Daniele; De Grandi, Sabrina; Feretti, Luigina; Giovannini, Gabriele; Grandi, Paola; Malizia, Angela; Matt, Giorgio; Molendi, Silvano

2000-05-01

291

Hard-on-Hard Lubrication in the Artificial Hip under Dynamic Loading Conditions  

PubMed Central

The tribological performance of an artificial hip joint has a particularly strong influence on its success. The principle causes for failure are adverse short- and long-term reactions to wear debris and high frictional torque in the case of poor lubrication that may cause loosening of the implant. Therefore, using experimental and theoretical approaches models have been developed to evaluate lubrication under standardized conditions. A steady-state numerical model has been extended with dynamic experimental data for hard-on-hard bearings used in total hip replacements to verify the tribological relevance of the ISO 14242-1 gait cycle in comparison to experimental data from the Orthoload database and instrumented gait analysis for three additional loading conditions: normal walking, climbing stairs and descending stairs. Ceramic-on-ceramic bearing partners show superior lubrication potential compared to hard-on-hard bearings that work with at least one articulating metal component. Lubrication regimes during the investigated activities are shown to strongly depend on the kinematics and loading conditions. The outcome from the ISO gait is not fully confirmed by the normal walking data and more challenging conditions show evidence of inferior lubrication. These findings may help to explain the differences between the in vitro predictions using the ISO gait cycle and the clinical outcome of some hard-on-hard bearings, e.g., using metal-on-metal. PMID:23940772

Sonntag, Robert; Reinders, Jörn; Rieger, Johannes S.; Heitzmann, Daniel W. W.; Kretzer, J. Philippe

2013-01-01

292

Hard X-ray emission in laser-induced vacuum discharge  

NASA Astrophysics Data System (ADS)

The dynamics of fast laser-induced vacuum discharge, with a rather small value of amplitude of current ([less-than-or-equal] 10 kA), as well as the voltage and energy of the capacitor bank ([less-than-or-equal] 20 kV and 20 J, respectively), have been investigated. It has been experimentally demonstrated that the initiations conditions determined by the energy and duration of the laser radiation, fundamentally determine the dynamics of the discharge. Two types of space and time separated plasma instabilities are revealed. It was found that the first of instabilities occurs at the initial stage of the discharge and is caused by a pinch structure, which takes place in front of a cathode jet extending in vacuum. The second type of instabilities arises at the top or recession of the current and is accompanied by the generation of hard (energy [greater-than-or-equal]100 keV) bremsstrahlung X-ray radiation from the anode area. The excess energy of the hard components of radiation over the potential of the current source is associated with the effects of plasma-erosive breaking.

Korobkin, Yu. V.; Romanov, I. V.; Rupasov, A. A.; Shikanov, A. S.; Gupta, P. D.; Khan, R. A.; Kumbhare, S. R.; Moorti, A.; Naik, P. A.

2005-09-01

293

Evidence that the bursting component of the X-ray radiation from 3C 111 originates in the PC-scale jet  

NASA Astrophysics Data System (ADS)

Evidence is presented indicating that the bursting component of the X-ray radiation detected in the nuclear region of the active radio galaxy 3C 111 comes from the blobs ejected in the pc-scale jet and not from the accretion disc. After each new outburst the radio flux density associated with it increases to a peak in ˜1 year and then subsides over a period of 1-2 years with the flux falling off exponentially as the blob moves outward and dissipates. Similar peaks (bursts) are seen in the X-ray light curve and a cross-correlation between the two shows a very high correlation with the X-ray peaks leading the radio peaks by ˜100 days. A second cross-correlation, this time between the radio event start times and the X-ray light curve, also shows a significant correlation. When this is taken together with the long (˜1 yr) delay between the start of each ejection event and its associated X-ray peak it indicates that this bursting component of the X-ray flux must be associated with the ejected blobs in the pc-scale jet and not with the accretion disc. Because X-ray telescopes do not have the resolution required to resolve the accretion disc area from the pc-scale jet, this paper is the first to present observational evidence that can pinpoint the point of origin of at least those long-timescale X-ray bursts with durations of 1-3 yrs.

Bell, M. B.; Comeau, S. P.

2012-05-01

294

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.

2012-10-12

295

Hard metal composition  

DOEpatents

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.

Sheinberg, H.

1983-07-26

296

Hard physics in PHENIX  

E-print Network

We review recent results on hard observables in p+p, d+A and A+A collisions obtained by the PHENIX experiment. Emphasis is put on those measurements that provide insight into the properties of hot QCD media expected to be created in nucleus-nucleus collisions at RHIC energies. Direct photon spectra, jet properties and heavy quarks production measured in p+p and d+Au collisions are compared to the same observables extracted in heavy ion collisions to find modifications due to the presence of hot QCD matter.

D. Peressounko; for the PHENIX collaboration

2005-12-08

297

Towards a New Component Composition Process  

Microsoft Academic Search

Component Based Development is considered to be a promising technology to cure the software crisis. However, until now designing and developing component-based applications turns out to be very hard. Current component based development not only involves a component configuration phase, but also writing a lot of glue -code. Much of the existing glue-code in current systems is written to \\

Wim Vanderperren; Bart Wydaeghe

2001-01-01

298

Exciting Hard Spheres  

E-print Network

We investigate the collision cascade that is generated by a single moving incident particle on a static hard-sphere gas. We argue that the number of moving particles at time t grows as t^{xi} and the number collisions up to time t grows as t^{eta}, with xi=2d/(d+2) and eta=2(d+1)/(d+2) and d the spatial dimension. These growth laws are the same as those from a hydrodynamic theory for the shock wave emanating from an explosion. Our predictions are verified by molecular dynamics simulations in d=1 and 2. For a particle incident on a static gas in a half-space, the resulting backsplatter ultimately contains almost all the initial energy.

T. Antal; P. L. Krapivsky; S. Redner

2008-05-25

299

Data Mining for CNC Machine Adjustment Decision in Hard Disk Drive Arm Manufacturing: Empirical Study  

Microsoft Academic Search

The numbers of hard disk drive heads manufactured in Thailand have increased rapidly in the past few years, and one of the\\u000a most important components of the hard disk drive head is the hard disk drive arm. This component has been produced in large\\u000a amounts and has been a major income source for a case study company. The manufacturing process

Pongsak Holimchayachotikul; Wimalin Laosiritaworn

300

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

NASA Technical Reports Server (NTRS)

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.

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

2003-01-01

301

EVOLUTIONS IN HARDNESS SCALES DEFINITION  

Microsoft Academic Search

A conventional characteristic of hardness measurements is the strong dependency on the official definition of each scale. For this reason, and to assure a good connection between National Metrology Institutes (NMIs), scientific organizations (e.g., IMEKO1) and international organizations for standardization (e.g., ISO 2 and OIML 3 ), a new Working Group on Hardness (WGH) was created a few years ago

Giulio Barbato; Alessandro Germak; Konrad Herrmann; Samuel Low

302

Effects of differences in hardness measurement procedures on the traceability chain and calibration process  

NASA Astrophysics Data System (ADS)

Establishment of traceability in hardness measurement is still under discussion at the ISO TC 164 SC 3 subcommittee on hardness testing. Two paths for establishing traceability are proposed for the Rockwell hardness measurement in ISO 6508-1. One way is taking a route to SI units through direct calibration of machine components, and the other way is taking a route to a hardness measurement standard through indirect calibration of machine performance. In addition to this, the difference in hardness measurement procedures between Rockwell and Brinell/Vickers hardness causes further confusion in establishing a traceability chain and an uncertainty evaluation process. This confusion is partly caused by the characteristics of hardness value, i.e. a procedure-dependent property. In this paper, methods used for the establishment of traceability for Rockwell, Brinell and Vickers hardness measurements are discussed based on the concept defined in the VIM.

Tak, Nae Hyung; Moo Lee, Hae; Bahng, Gunwoong

2013-06-01

303

Hard rock drilling problems explained by hard rock pressure plots  

SciTech Connect

Hard rock drilling problems are frustrating. Hard rock pore pressure interpretation is baffling. Because of slow drilling in hard streaks and absence of kicks (in overpressured shale sections), it is generally assumed pore pressures are close to ''normal'' over long depth intervals. Many hard rock drilling problems could not be logically explained, if this were the case. Nothing could be further from the truth. Hard rocks are difficult to drill because of the extreme zig-zags from overpressured shales to sub-normally pressured sands and carbonates. It is impossible to drill anywhere near balanced in both situations, simultaneously. Hard rock drilling problems caused by underbalance or overbalance (or both) are a result. But, a better understanding of the presence and magnitude of these pressure shifts will help minimize the worst extremes of imbalance and more intelligently strike an optimum compromise, realizing that mud density and, especially, mud chemistry can never completely solve these hard rock drilling problems. Well log pressure plots in these erratic stratigraphies are so difficult to interpret that they often have been considered useless. The example pore pressure plots shown here, including the Pressure Evaluation Profile (PEP) log -- a side by side comparison of several different pressure sensitive responses -- help interpret and explain many of these problems in a simple, logical manner.

Gill, J.A.

1983-02-01

304

Hardness Assurance Techniques for New Generation COTS Devices  

NASA Technical Reports Server (NTRS)

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.

Lee, C. I.; Rax, B. G.; Johnston, A. H.

1996-01-01

305

THE HARD X-RAY SPECTRUM OF NGC 1365: SCATTERED LIGHT, NOT BLACK HOLE SPIN  

SciTech Connect

Active galactic nuclei (AGNs) show excess X-ray emission above 10 keV compared with extrapolation of spectra from lower energies. Risaliti et al. have recently attempted to model the hard X-ray excess in the type 1.8 AGN NGC 1365, concluding that the hard excess most likely arises from Compton-scattered reflection of X-rays from an inner accretion disk close to the black hole. Their analysis disfavored a model in which the hard excess arises from a high column density of circumnuclear gas partially covering a primary X-ray source, despite such components being required in the NGC 1365 data below 10 keV. Using a Monte Carlo radiative transfer approach, we demonstrate that this conclusion is invalidated by (1) use of slab absorption models, which have unrealistic transmission spectra for partial covering gas, (2) neglect of the effect of Compton scattering on transmitted spectra, and (3) inadequate modeling of the spectrum of scattered X-rays. The scattered spectrum is geometry-dependent and, for high global covering factors, may dominate above 10 keV. We further show that, in models of circumnuclear gas, the suppression of the observed hard X-ray flux by reprocessing may be no larger than required by the ''light bending'' model invoked for inner disk reflection, and the expected emission line strengths lie within the observed range. We conclude that the time-invariant ''red wing'' in AGN X-ray spectra is probably caused by continuum transmitted through and scattered from circumnuclear gas, not by highly redshifted line emission, and that measurement of black hole spin is not possible.

Miller, L. [Department of Physics, Oxford University, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom); Turner, T. J. [Department of Physics, University of Maryland Baltimore County, Baltimore, MD 21250 (United States)

2013-08-10

306

Synthesis and characterization of hard/soft bimagnetic nanoparticles  

NASA Astrophysics Data System (ADS)

Bimagnetic nanoparticles are synthesized from high-temperature solution method by growing soft magnetic phases on a hard magnetic phase. The hard phase is chosen as the FePt phase and the soft phases include Fe3O4, CoFe2O4 and FeCo. The soft phases can be coated or attached to the hard phase by changing reaction conditions. When the soft phases are coated on the hard phase, core/shell structured bimagnetic nanoparticles are formed; when the soft phases are attached to the hard phase, brick-like bimagnetic nanoparticles are formed. Magnetic properties of these nanoparticles are affected by dimensions of the soft and hard components due to the exchange coupling between them. Upon reductive annealing, an assembly of the bimagnetic nanoparticles is transformed into a hard magnetic nanocomposite with enhanced energy product which is 35% higher than single FePt phase. With proper choice of materials and dimension of both phases, these bimangetic nanoparticles may be used as building blocks for novel functional nanomaterials for various applications.

Nandwana, Vikas; Shankar Chaubey, Girija; Yano, Kazuaki; Liu, J. Ping

2007-03-01

307

Discovery of hard X-ray features around hotspots of Cygnus A  

E-print Network

We present results of analysis of a Chandra observation of Cygnus A in which the X-ray hotspots at the ends of the jets are mapped in detail. A hardness map reveals previously unknown structure in the form of outer and inner hard arcs around the hotspots, with hardness significantly enhanced compared with the hotspot central regions. The outer hard arcs may constitute the first detection of the bow shock; the inner hard arcs may reveal where the jets impact on the hotspots. We argue that these features cannot result from electrons radiating by the synchrotron self-Compton process. Instead we consider two possible sources of the hard emission: the outer arcs may be due to thermal radiation of hot intracluster gas compressed at the bow shock. Alternatively, both outer and inner arcs may be due to synchrotron radiation of electrons accelerated in turbulent regions highly perturbed by shocks and shear flows. Comparison of measured hardness ratios with simulations of the hardness ratios resulting from these processes show that it is more diffcult to explain the observations with a thermal model. Although we cannot rule out a thermal model, we argue in favour of the non-thermal explanation. The hard regions in the secondary hotspots suggest that jet activity is still powering these hotspots.

M. Balucinska-Church; M. Ostrowski; L. Stawarz; M. J. Church

2004-11-17

308

Nanopatterned ferroelectrics for ultrahigh density rad-hard nonvolatile memories.  

SciTech Connect

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.

Brennecka, Geoffrey L.; Stevens, Jeffrey; Scrymgeour, David; Gin, Aaron V.; Tuttle, Bruce Andrew

2010-09-01

309

Radiation Damage to Electronics in the Beam Tunnel of the Next Linear Collider  

SciTech Connect

Radiation damage to electronics in the Linac tunnel of the Next Linear Collider due to ionizing and non-ionizing effects has been estimated with detailed FLUKA simulations. Results for total dose deposited in silicon and for displacement damage by neutrons, protons and charged pions are presented. It is shown that non-radiation-hard electronics could be severely damaged unless sufficiently shielded against radiation. A scenario is proposed in which the electronic components are located in niches in the beam tunnel wall which are shielded by layers of polyethylene.

Roesler, Stefan

2000-06-27

310

Ejs Hard Disk Gas Model  

NSDL National Science Digital Library

The Ejs Hard Disk Gas model displays a two-dimensional gas made out of hard disks. Particles are initialized with a speed v=1 in a random direction and move with constant velocity until a collision occurs. You can modify this simulation if you have Ejs installed by right-clicking within the plot and selecting âOpen Ejs Modelâ from the pop-up menu item. Ejs Hard Disk Gas model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_newton_HardDiskGas.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models for statistical mechanics are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Christian, Wolfgang

2008-07-06

311

Confined Hard Disk System Model  

NSDL National Science Digital Library

The Confined Hard Disk System is an idealized statistical mechanics model that simulates a two-dimensional system of hard disks confined to a box with a constant temperature thermal reservoir at one end and a movable piston at the other. Slow-moving particles are color-coded as blue and fast particles are color-coded as yellow. The model computes and plots the time evolution of the kinetic energy K per particle, the pressure P, and the volume V. The model also displays histograms and mean values of these quantities. The Confined Hard Disk System was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_stp_hd_ConfinedHardDiskSystem.jar file will run the program if Java is installed.

Christian, Wolfgang

2010-12-27

312

STP Hard Disks Metropolis Program  

NSDL National Science Digital Library

The STP Hard Disks Metropolis program is a Monte Carlo simulation of hard disks in two dimensions. The default initial condition is a rectangular configuration of N=64 particles in a box of length L = 40. You can slowly increase the density of the gas (by setting the minimum scale length between centers to a value slightly less than 1) to explore phase transitions. STP HardDisksMetropolis is part of a suite of Open Source Physics programs that model aspects of Statistical and Thermal Physics (STP). The program is distributed as a ready-to-run (compiled) Java archive. Double-clicking the stp_HardDisksMetropolis.jar file will run the program if Java is installed on your computer. Additional programs can be found by searching ComPADRE for Open Source Physics, STP, or Statistical and Thermal Physics.

Gould, Harvey; Tobochnik, Jan; Christian, Wolfgang; Cox, Anne

2009-03-06

313

Radio imaging observations of hard x-ray microflares observed by RHESSI  

NASA Astrophysics Data System (ADS)

We describe the properties of two sets of microflares observed simultaneously by RHESSI (Ramaty High Energy Solar Spectroscopic Imager) in hard X-rays and by two radio imaging instruments--NoRH (Nobeyama Radio Heliograph) in microwaves (17 GHz) and NRH (Nancay Radio Heliograph) at metric wavelengths. The two sets of events occurred in two different time zones, and as a result we do not have simultaneous imaging data in microwaves and metric wavlengths for the same RHESSI events. We'll discuss four events--two observed by NoRH in microwaves and two observed by NRH in meter waves, along with RHESSI events. The microwave (17 GHz) events occurred in AR 9934 at 03:58 UT May 3, 2002 and at 05:08 UT May 4, 2002. We have detected microwave (17 & 34 GHz) emissions in association with RHESSI microflares in the energy range 3-50 keV. The microwave emission comes from footpoints for higher energies, and from the entire mini or small flaring loop for lower energies. The relative positions of microwaves and hard X-rays are as they should be in normal flares. Sometimes the two sources coincide, at other times the two sources are at opposite ends of the flaring loop. One sees the mini flaring loops clearly in NoRH images. RHESSI maps at the time of maximum X-ray emission during the event of May 3, 2002 clearly show an X-ray loop in the range 3-6 keV and two footpoints of the loop in the 6-12 and 12-25 keV ranges. These footpoints are located above opposite magnetic polarities as seen in overlays of hard X-ray images on the MDI images. The MDI magnetograms taken before the microflares show rapid evolution of the magnetic field, including sometimes the emergence of a new region. The hard X-ray spectrum of microwave associated RHESSI microflares can be fit by a thermal component (EM ˜ 3× 1046 cm-3) at low energies (3-6 keV) and a nonthermal component (with slope -3.2) at higher energies. The two metric events imaged by NRH occurred on August 5 and September 3, 2003, one located on the disk and the other at the limb. The RHESSI microflare sources are compact. They are accompanied by a series of metric type III bursts at 150-410 MHz originating from sources located above the RHESSI HXR source. Their source positions show frequency dispersion as expected from plasma radiation sources. The properties of these microflare sources in hard X-rays, microwave and meter wavelengths will be discussed.

Kundu, M.; Trottet, G.; Garaimov, V.; Grigis, P.

314

Residual stress control and design of next-generation ultra-hard gear steels  

NASA Astrophysics Data System (ADS)

In high power density transmission systems, Ni-Co secondary hardening steels have shown great potential for next-generation gear applications due to their excellent strength, toughness and superior fatigue performance. Study of residual stress generation and evolution in Ferrium C61 and C67 gear steels revealed that shot peening and laser peening processes effectively produce desired beneficial residual stress in the steels for enhanced fatigue performance. Surface residual stress levels of -1.4GPa and -1.5GPa were achieved in shot peened C61 and laser peened C67, respectively, without introducing large surface roughness or defects. Higher compressive residual stress is expected in C67 according to a demonstrated correlation between attainable residual stress and material hardness. Due to the lack of appropriate shot media, dual laser peening is proposed for future peening optimization in C67. A novel non-destructive synchrotron radiation technique was implemented and applied for the first time for residual stress distribution analysis in gear steels with large composition and property gradients. Observed substantial residual stress redistribution and material microstructure change during the rolling contact fatigue screening test with extremely high 5.4GPa load indicates the unsuitability of the test as a fatigue life predictor. To exploit benefits of higher case hardness and associated residual stress, a new material and process (CryoForm70) aiming at 70Rc surface hardness was designed utilizing the systems approach based on thermodynamics and secondary hardening mechanisms. The composition design was first validated by the excellent agreement between experimental and theoretical core martensite start temperature in the prototype. A novel cryogenic deformation process was concurrently designed to increase the case martensite volume fraction from 76% to 92% for enhanced strengthening efficiency and surface hardness. High temperature vacuum carburizing was optimized for desired carbon content profiles using carbon diffusion simulation in the multi-component system. After cyclic tempering with intermediate cryogenic treatment, a case hardness of 68.5 +/- 0.3Rc at 0.72 +/- 0.2wt% carbon content was achieved. The design demonstrated the effectiveness of cryogenic deformation in promoting martensite transformation for high carbon and high alloy steels. Good agreement between achieved and predicted case and core hardness supports the effectiveness of the computational design approach.

Qian, Yana

315

HARD CLAM HYBRIDS FOR FLORIDAAQUACULTURE: HATCHERY CULTURE  

E-print Network

HARD CLAM HYBRIDS FOR FLORIDAAQUACULTURE: HATCHERY CULTURE John Scarpa: Harbor Branch Oceanographic and Aquatic Sciences, Gainesville, FL 32653 Introduction The hard clam (Mercenaria mercenaria notata summers of Florida. Southern hard clams, Mercenaria campechiensis, may have production traits

Florida, University of

316

Easy Problems are Sometimes Hard  

Microsoft Academic Search

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

Ian P. Gent; Toby Walsh

1994-01-01

317

Annihilation radiation in cosmic gamma-ray bursts  

NASA Astrophysics Data System (ADS)

The emission features observed in the energy spectra of cosmic gasmma-ray bursts imply the existence of two radiation components of comparable intensity. The softer component is similar to the continua of featureless bursts. The fast decrease in the intensity of this radiation with increasing photon energy is apparently due to the neutron star's magnetosphere being opague to hard photons because of the formation of electron-positron pairs in single-photon (gamma, B) and two-photon (gamma, gamma) processes. The hard component originates from the annihilation of electron-positron pairs, its spectrum representing a broad line with an extended power-law wing. Such a shape of the spectrum is apparently due to either thermal broadening in a source with a spatially inhomogeneous and rapidly time-varying plasma temperature, or nonthermal energy distribution of particles in their motion along the magnetic field lines. It is assumed that the sources of these components are spatially separated, the annihilation radiation escaping from the polar regions of a strongly magnetized neutron star in a collimated beam without appreciable attenuation.

Golenetskii, S. V.; Mazets, E. P.; Aptekar, R. L.; Gurian, Iu. A.; Ilinskii, V. N.

1986-07-01

318

Interfacial phenomena in hard-rod fluids  

NASA Astrophysics Data System (ADS)

This thesis addresses questions of interfacial ordering in hard-rod fluids at coexistence of the isotropic and nematic phases and in their contact with simple model substrates. It is organized as follows. Chapter II provides some background information about the relation between the statistical mechanical and thermodynamical level of descriptions of bulk hard-rod fluids, as well as introduces the asymptotically exact Onsager model, and some basic facts of interfacial thermodynamics. Chapter III represents studies of the simplest free IN interface in a fluid of monodisperse Onsager hard rods. For the analysis of this system we develop an efficient perturbative method to determine the (biaxial) one-particle distribution function in inhomogeneous systems. Studies of the free planar isotropic-nematic interfaces are continued in Chapter IV, where they are considered in binary mixtures of hard rods. For sufficiently different particle shapes the bulk phase diagrams of these mixtures exhibit a triple point, where an isotropic (I) phase coexists with two nematic phases (N1 and N2) of different composition. For all explored mixtures we find that upon approach of the triple point the IN2 interface shows complete wetting by an intervening N1 film. We compute the surface tension of isotropic-nematic interfaces, and find a remarkable increase with fractionation. These studies are complemented by an analysis of bulk phase behavior and interfacial properties of nonadditive binary mixtures of thin and thick hard rods in Chapter V. The formulation of this model was motivated by recent experiments in the group of Fraden, who explored the phase behavior of a mixture of viruses with different effective diameters. In our model, species of the same types are considered as interacting with the hard-core repulsive potential, whereas the excluded volume for dissimilar rods is taken to be larger (smaller) then for the pure hard rods. Such a nonadditivity enhances (reduces) fractionation at the isotropic-nematic (IN) coexistence and may induce (suppress) a demixing of the high-density nematic phase into two nematic phases of different composition (N1 and N2). Studies of their interfaces show an increase of the surface tension with fractionation at the IN interface, and complete wetting of the IN2 interface by the N1 phase upon approach of the triple point coexistence. In all explored cases bulk and interfacial properties of the nonadditive mixtures exhibit a surprising similarity with the properties of additive mixtures of larger diameter ratio. In Chapter VI we consider properties of a monodisperse hard-rod fluid in contact with the single wall (W). Studies of surface properties of a fluid of Onsager hard rods represent significant numerical difficulties, therefore we consider a simpler model fluid of hard rods with a restricted number of allowed orientations. Within this model, known as the Zwanzig model, we explore the thermodynamic properties of a fluid of monodisperse hard rods in contact with a model substrate represented by a hard wall with a short-ranged attractive or repulsive ``tail''. The attraction enhances the orientational ordering near the wall in both isotropic and nematic phases, and shifts the transition from uniaxial (U) to biaxial (B) symmetry in the isotropic surface layer to lower chemical potentials, whereas the wetting properties of the substrate remain similar to those of the pure hard wall. The soft repulsion reduces the density in the surface layer, which leads to the shift (or even suppression) of the UB transition, and strong modification of wetting properties. At the WI interface one always finds the wetting transition at sufficiently large repulsion, whereas a drying transition at the WN interface is observed only for sufficiently long-ranged potentials. In Chapter VII we explore some limitations of models of hard-rod fluids with a finite number of allowed orientations. Within Onsager's second virial theory we construct their bulk phase diagrams. For a one-component fluid, we show that the discretization of the orien

Shundyak, K. Y.

2004-05-01

319

Polarization effects on hard target calibration of lidar systems  

NASA Technical Reports Server (NTRS)

The theory of hard target calibration of lidar backscatter data, including laboratory measurements of the pertinent target reflectance parameters, is extended to include the effects of polarization of the transmitted and received laser radiation. The bidirectional reflectance-distribution function model of reflectance is expanded to a 4 x 4 matrix allowing Mueller matrix and Stokes vector calculus to be employed. Target reflectance parameters for calibration of lidar backscatter data are derived for various lidar system polarization configurations from integrating sphere and monostatic reflectometer measurements. It is found that correct modeling of polarization effects is mandatory for accurate calibration of hard target reflectance parameters and, therefore, for accurate calibration of lidar backscatter data.

Kavaya, Michael J.

1987-01-01

320

30 CFR 77.1710-1 - Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced...  

Code of Federal Regulations, 2012 CFR

...Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced...Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively different in color...

2012-07-01

321

30 CFR 77.1710-1 - Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced...  

Code of Federal Regulations, 2011 CFR

...Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced...Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively different in color...

2011-07-01

322

30 CFR 75.1720-1 - Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced...  

Code of Federal Regulations, 2011 CFR

...Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced...Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively different in color...

2011-07-01

323

30 CFR 75.1720-1 - Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced...  

Code of Federal Regulations, 2012 CFR

...Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced...Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively different in color...

2012-07-01

324

30 CFR 77.1710-1 - Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced...  

Code of Federal Regulations, 2013 CFR

...Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced...Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively different in color...

2013-07-01

325

30 CFR 77.1710-1 - Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced...  

Code of Federal Regulations, 2010 CFR

...Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced...Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively different in color...

2010-07-01

326

30 CFR 75.1720-1 - Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced...  

Code of Federal Regulations, 2010 CFR

...Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced...Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively different in color...

2010-07-01

327

30 CFR 75.1720-1 - Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced...  

Code of Federal Regulations, 2013 CFR

...Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced...Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively different in color...

2013-07-01

328

CONTROL OF LASER RADIATION PARAMETERS: Generation of Stark spectral components in Nd:YAP and Nd:YAG lasers by using volume Bragg gratings  

NASA Astrophysics Data System (ADS)

Generation of Stark spectral components in free-running Q-switched Nd:YAP (1064 nm and 1073 nm) and Nd:YAG (1062 nm) lasers is obtained. For this purpose reflecting volume Bragg gratings placed into the laser resonator and permitting to tune the laser emission spectrum were used. Stable generation of Stark components in both lasers is obtained. The possibility of obtaining two-frequency generation in an Nd-glass laser with the help of these gratings is shown.

Vorob'ev, Nikolai S.; Glebov, L. B.; Smirnov, V. I.; Chapurin, I. V.

2009-01-01

329

Estimation of global solar radiation in Nigeria using a modified Angstrom model and the trend analysis of the allied meteorological components  

NASA Astrophysics Data System (ADS)

The trend of some common and related atmospheric variables were investigated in the light of climate change on annual time scale and a suitable scheme was further developed for the simulation of annual global solar radiation in Nigeria. In this connection, annual trends of global solar radiation, air temperature, precipitation, relative humidity and sunshine hours was carried out, covering about 13 tropical stations during 1975-2006 in Nigeria using F-test as the significance test technique. It was found that nine stations exhibited an upward trend in global solar radiation series, of which 6 passed F-test at 1% significant level. At 11 stations, precipitation had shown an increasing trends but none passed F-test at 2.5% and hence, not significant. About 98.8% of the stations displayed an upward trend in sunshine hours of which 16% passed F-test at 1% significant level. On trend analysis for relative humidity series, eight stations exhibited a positive trend and only one station passed F-test at 1% significant level. The trend of temperature series in Nigeria under the period under investigation was found to be increasing at 12 stations and eight stations passed the F-test at 1% significant level. The other objective of this study was to determine a more suitable empirical equation by modifying Angstrom model for the estimation of global solar radiation using all data for all 14 stations pooled together to predict global solar radiation using linear and multiple linear regression. This was done to improve the low performance of the Angstrom model used for the annual estimation of global solar radiation. The model parameters 'a' and 'b' of Angstrom model were parameterized in terms of the geographical locations (latitude, longitude and elevation) and the meteorological variables (sunshine hour, precipitation, relative humidity and temperature), respectively. This scheme gave better simulation of the global solar radiation compared wi! th other schemes and the original Angstrom models. In addition, the pr eferential consideration of relative humidity to precipitation as potent contributing factor in the estimation of global solar radiation was also established.

Ogolo, E. O.

2014-06-01

330

Radiation Processing -an overview  

E-print Network

1 Radiation Processing - an overview Arne Miller Risø High Dose Reference Laboratory Risø DTU DK irradiation · Material modification #12;3 Content ­ Part 2 · Environmental applications · Other applications ­ radiation hardness testing ­ semiconductors ­ microlitography ­ gem stones · Dosimetry · Quality assurance

331

Hard Hat Use and Inspection Hard hats are an important piece of personal protective equipment (PPE). Hard hats worn  

E-print Network

Hard Hat Use and Inspection Hard hats are an important piece of personal protective equipment (PPE). Hard hats worn at Berkeley Lab must comply with the requirements of ANSI Z89.1 for impact protection follow manufacturer's recommendations for specific inspection procedures. Hard Hat Inspection - Bullard

Eisen, Michael

332

Hard diffraction -- 20 years later  

E-print Network

The idea of diffractive processes with a hard scale involved, to resolve the underlying parton dynamics, was published 1985 and experimentally verified 1988. Today hard diffraction is an active research field with high-quality data and new theoretical models. The trend from Regge-based pomeron models to QCD-based parton level models has given insights on QCD dynamics involving perturbative gluon exchange mechanisms, including the predicted BFKL-dynamics, as well as novel ideas on non-perturbative colour fields and their interactions. Extrapolations to the LHC include the interesting possibility of diffractive Higgs production.

Gunnar Ingelman

2005-12-12

333

On Hadronic Models for the Anomalous $?$-ray Emission Component in GRB 941017  

E-print Network

Gonz\\'alez et al. (2003) have reported the discovery of an anomalous radiation component from ~ 1 -- 200 MeV in GRB 941017. This component varies independently of and contains >~ 3 times the energy found in the prompt ~ 50 keV -- 1 MeV radiation component that is well described by the relativistic synchrotron-shock model. Acceleration of hadrons to very high energies by GRBs could give rise to a separate emission component. Two models, both involving acceleration of ultra-high energy cosmic rays with subsequent photomeson interactions, are considered. The first involves a pair-photon cascade initiated by photohadronic processes in the GRB blast wave. Calculations indicate that the cascade produces a spectrum that is too soft to explain the observations. A second model is proposed where photopion interactions in the GRB blast-wave shell give rise to an escaping collimated neutron beam. The outflowing neutrons undergo further photopion interactions to produce a beam of hyper-relativistic electrons that can lose most of their energy during a fraction of a gyroperiod in the Gauss-strength magnetic fields found in the circumburst medium. This secondary electron beam produces a hard synchrotron radiation spectrum that could explain the anomalous component in GRB 941017.

C. D. Dermer; A. Atoyan

2003-12-09

334

COMPONENTS OF LASER SYSTEMS AND PROCESSES OCCURRING IN THEM: Fast-response system for stabilization of the axis of the angular distribution of laser radiation  

NASA Astrophysics Data System (ADS)

A fast-acting system for stabilization of the axis of the angular distribution of radiation from a continuous-flow CO2 laser is considered. The results of a simulation experiment are reported: they show that it is possible to suppress, by 24-28 dB, fluctuations of the position of the axis in the spectral range 0-20 Hz. This makes the proposed system a promising method for large-aperture laser beams.

Vinogradov, E. G.; Glebova, S. N.; Pavlov, N. V.; Razhenkov, E. T.

1988-09-01

335

Synchrotron Radiation  

SciTech Connect

This book covers the physical aspects of synchrotron radiation generation and is designed as a textbook and reference for graduate students, teachers and scientists utilizing synchrotron radiation. It is my hope that this text may help especially students and young researchers entering this exciting field to gain insight into the characteristics of synchrotron radiation. Discovered in 1945, synchrotron radiation has become the source of photons from the infrared to hard x-rays for a large community of researchers in basic and applied sciences. This process was particularly supported by the development of electron accelerators for basic research in high energy physics. Specifically, the development of the store ring and associated technologies resulted in the availability of high brightness photon beams far exceeding other sources. In this text, the physics of synchrotron radiation for a variety of magnets is derived from first principles resulting in useful formulas for the practitioner. Since the characteristics and quality of synchrotron radiation are intimately connected with the accelerator and electron beam producing this radiation, a short overview of relevant accelerator physics is included.

Wiedemann, Helmut

2003-08-11

336

Hard X-Ray and Gamma Ray Detectors and Applications V, edited by Larry A. Franks, Arnold Burger, Ralph B. James, Paul L. Hink, Proceedings of SPIE Vol. 5198 (SPIE, Bellingham, WA, 2004)  

E-print Network

Hard X-Ray and Gamma Ray Detectors and Applications V, edited by Larry A. Franks, Arnold Burger-time". Initial tests have shown these devices to be extremely radiation hard and potentially capable of operating to take advantage of the radiation hardness of gas-filled fission chambers while being compact like

Shultis, J. Kenneth

337

Electronic Components  

NSDL National Science Digital Library

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.

Lesurf, Jim

2013-08-13

338

Hard Trying and These Recipes  

ERIC Educational Resources Information Center

Writers thrive when they are motivated to work hard, have regular opportunities to practice and reflect, and benefit from a knowledgeable teacher who knows writing. Student feedback to lessons during writing workshop helped guide Nancie Atwell in her quest to provide the richest and most efficient path to better writing.

Atwell, Nancie

2003-01-01

339

Indentation hardness testing of rock  

Microsoft Academic Search

The indentation testing was used for characterisation of hardness of rock materials. During the test, an indentor under applied load penetrated into the rock surface forming a crater. The testing procedure was developed to be in line with other ISRM Suggested Methods. The results show that standardised indentation testing allows for characterisation of mechanical properties of rock and that there

T Szwedzicki

1998-01-01

340

TESTING HARDNESS OF METAL ITEMS WITH MET-UD COMBINED PORTABLE HARDNESS TESTER  

Microsoft Academic Search

A new approach to portable hardness testers has been developed and introduced. It makes it possible to inspect hardness by one and the same hardness tester applying both, the ultrasonic contact impedance method and rebound method. Hardness tester wide possibilities which allow to inspect hardness of metal and alloy products with all standardized scales (Rockwell, Brinell, Vickers and Shore) have

Edward Aslanyan; Alexander Doynikov; Victor Pivovarov

341

XMM-Newton Detection of Hard X-ray Emission in the Nitrogen-Type Wolf-Rayet Star WR110  

E-print Network

We have used the excellent sensitivity of XMM-Newton to obtain the first high-quality X-ray spectrum of a Wolf-Rayet (WR) star which is not known to be a member of a binary system. Our target, the nitrogen-type star WR 110 (= HD 165688) was also observed and detected with the VLA at four different frequencies. The radio data are in excellent agreement with that expected for free-free wind emission. and the ionized mass-loss rate is derived. The X-ray emission measure distribution shows a dominant contribution from cool plasma at kT$_{cool}$ = 0.5 keV (6 MK) which is only weakly absorbed. We argue that this cool emission originates at hundreds of radii if the wind is spherical and homogeneous and derive shock velocities and the X-ray filling factor using radiative shock models. A surprising result is the unambiguous detection of a hard X-ray component clearly seen in the hard-band images and the spectra. This hard component accounts for about half of the observed flux and can be acceptably fitted by a hot optically thin thermal plasma or a power-law model. If the emission is thermal, then a temperature kT$_{hot}$ $\\geq$ 3 keV is derived. Such high temperatures are not predicted by current instability-driven wind shock models. We examine several alternatives and show that the hard emission could be accounted for by the WR wind shocking onto a close stellar companion which has so far escaped detection. However, until persuasive evidence for binarity is found we are left with the intriguing possibility that the hard X-ray emission is produced entirely by the Wolf-Rayet star.

S. L. Skinner; S. A. Zhekov; M. Guedel; W. Schmutz

2002-03-18

342

Hardness ratio evolutionary curves of gamma-ray bursts expected by the curvature effect  

E-print Network

We have investigated the gamma-ray bursts pulses assumed to arise from relativistically expending fireballs. We find, due to the curvature effect, the evolutionary curve of the raw hardness ratio (when the background count is included) varies significantly, depending on the hardness of a burst. For a soft burst, an upside-down pulse of its raw hardness ratio curve (HRC) would be observed; for a hard burst, its raw HRC shows a pulse-like profile with a sinkage in its decaying phase; for a very hard burst, the raw HRC possesses a pulse-like profile without a sinkage in its decaying phase. For a pulse-like raw HRC as shown in the case of the hard and very hard bursts, its peak would appear in advance of that of the corresponding light curve. We have studied here the HRC of GRB 920216, GRB 920830 and GRB 990816 in detail. The features of the raw HRC expected in the hard burst are observed in these bursts. A fit to the three bursts shows that the curvature effect alone could indeed account for the predicted characteristics of HRCs. In addition, we find that the observed hardness ratio tends to be harder at the beginning of the pulses than what the curvature effect could predict and be softer at the late time of the pulses. We believe this is an evidence showing the existence of intrinsic hard-to-soft radiation.

Y. -P. Qin; C. -Y. Su; J. H. Fan; A. C. Gupta

2007-01-04

343

Long-term variability of AGN at hard X-rays  

NASA Astrophysics Data System (ADS)

Aims: Variability at all observed wavelengths is a distinctive property of active galactic nuclei (AGN). Hard X-rays provide us with a view of the innermost regions of AGN, mostly unbiased by absorption along the line of sight. Characterizing the intrinsic hard X-ray variability of a large AGN sample and comparing it to the results obtained at lower X-ray energies can significantly contribute to our understanding of the mechanisms underlying the high-energy radiation. Methods: Swift/BAT provides us with the unique opportunity to follow, on time scales of days to years and with regular sampling, the 14-195 keV emission of the largest AGN sample available up to date for this kind of investigation. As a continuation of an early work using the first 9 months of BAT data, we study the amplitude of the variations and their dependence on subclass and on energy, for a sample of 110 radio quiet and radio loud AGN selected from the BAT 58-month survey. Results: About 80% of the AGN in the sample are found to exhibit significant variability on month-to-year time scales. In particular, radio loud sources are the most variable, and Seyfert 1.5-2 galaxies are slightly more variable than Seyfert 1, while absorbed and unabsorbed objects show similar timing properties. The amplitude of the variations and their energy dependence are incompatible with variability being driven at hard X-rays by changes in the absorption column density. In general, the variations in the 14-24 and 35-100 keV bands are correlated well, suggesting a common origin to the variability across the BAT energy band. However, radio quiet AGN display on average 10% larger variations at 14-24 keV than at 35-100 keV, and a softer-when-brighter behavior for most of the Seyfert galaxies with detectable spectral variability on a time scale of a month. In addition, sources with harder spectra are found to be more variable than softer ones, unlike what it is observed below 10 keV. These properties are generally consistent with a variable, in flux and shape, power law continuum, pivoting at energies ? 50 keV, to which a constant reflection component is superposed. When the same time scales are considered, the timing properties of AGN at hard X-rays are comparable to those at lower energies, with at least some of the differences possibly ascribable to components contributing differently in the two energy domains (e.g., reflection, absorption). Table 2 is available in electronic form at http://www.aanda.org

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

2014-03-01

344

Increased Radiation Hardness of Short-Channel Electron-Irradiated Si1-xGex Source/Drain p-Type Metal Oxide Semiconductor Field-Effect Transistors at Higher Ge Content  

NASA Astrophysics Data System (ADS)

In this work, it is shown that the maximum hole mobility of compressively strained Si1-xGex source-drain (S/D) p-MOSFETs is degraded after high-fluence 2 MeV electron irradiation, suggesting the loss of strain in the Si channel caused by the radiation-induced displacement damage. This is supported by the fact that the mobility reduction after irradiation is larger for SiGe S/D devices than for Si references at the same fluence (5×1017 cm-2) and becomes more pronounced for shorter gate lengths. At the same time, however, it is found that the extent of mobility reduction becomes smaller for p-MOSFETs with a higher Ge content (35%, compared with 20 or 30%). Finally, it is concluded that, for shorter devices, the displacement-damage-related degradation mechanism becomes less pronounced with increasing Ge content in Si1-xGex S/D regions.

Nakashima, Toshiyuki; Yoneoka, Masashi; Tsunoda, Isao; Takakura, Kenichiro; Bargallo Gonzalez, Mireia; Simoen, Eddy; Claeys, Cor; Yoshino, Kenji

2013-09-01

345

Wear behaviour of composite laminates with hard superficial layers  

SciTech Connect

Intrinsic material properties of polymeric composite materials as rigidity and mechanical strength can be satisfactory for many applications while the superficial properties as wear resistance and corrosion cannot be satisfactory for specific employment conditions. Recent studies have shown that it is possible to change the superficial properties of composite laminates by the deposition of hard material films. The coating of composite components, however, brings a major complication during the fabrication process, for a special technological step is necessary. In this paper the authors propose to improve the superficial properties using hard particles embedded into the resin directly during the fabrication of the external layers of the laminate. In this way laminates have been obtained, where the superficial layers have been impregnated with resin with different hard particles. Results of wear tests show an increase of the wear resistance while SEM analysis show the rupture mechanisms of the fibers.

Visconti, I.C.; Langella, A.; Capuano, P. [Univ. of Naples (Italy). Dept. of Materials and Production

1993-12-31

346

COMPONENTS OF LASER SYSTEMS AND STABILITY PROBLEMS: Parametric generation of tunable picosecond light pulses as a result of pumping with radiation from a stimulated Raman scattering compressor  

NASA Astrophysics Data System (ADS)

Typical parametric oscillations were observed in a laser with a stimulated Raman scattering compressor. This laser generated pulses of ~ 15 ps duration at a wavelength of 0.63 ?m and the width of the spectrum was ~ 0.7 cm- 1. The parametric radiation was tunable within the range 1-1.5 ?m. A study was made of the statistical properties of the generation process. The energy stability of the pulses generated in such an optical parametric oscillator was twice as high as in the case when pumping was provided by a picosecond YAG:Nd laser with passive mode locking.

Buzyalis, R. R.; Dementjev, Aleksandr S.; Deringas, A. L.; Kabelka, V. I.; Kosenko, E. K.; Milyauskas, A. A.

1988-08-01

347

LIFE Materials: Topical Assessment Report for LIFE Volume 1 TOPIC: Solid First Wall and Structural Components TASK: Radiation Effects on First Wall  

SciTech Connect

This report consists of the following chapters: CHAPTER A: LIFE Requirements for Materials. Part 1: The structure of the First Wall--Basic requirements; A qualitative view of the challenge; The candidate materials; and Base-line material's properties. CHAPTER B: Summary of Existing Knowledge--Brief historical introduction; Design window; The temperature window; Evolution of the design window with damage; Damage calculations; He and H production; Swelling resistance; Incubation dose for swelling; Design criterion No. 1, Strength; Design criterion No. 2, Corrosion resistance; Design criterion No. 3, Creep resistance; Design criterion No. 4, Radiation induced embrittlement; and Conclusions. CHAPTER C: Identification of Gaps in Knowledge & Vulnerabilities. CHAPTER D: Strategy and Future Work.

Caro, A

2008-11-26

348

How do monomeric components of a polymer gel dosimeter respond to ionising radiation: A steady-state radiolysis towards preparation of a 3D polymer gel dosimeter  

NASA Astrophysics Data System (ADS)

Ionising radiation-induced reactions of aqueous single monomer solutions and mixtures of poly(ethylene glycol) diacrylate (PEGDA) and N, N'-methylenebisacrylamide (Bis) in a steady-state condition are presented below and above gelation doses in order to highlight reactions in irradiated 3D polymer gel dosimeters, which are assigned for radiotherapy dosimetry. Both monomers are shown to undergo radical polymerisation and cross-linking, which result in the measured increase in molecular weight and radius of gyration of the formed polydisperse polymer coils. The formation of nanogels was also observed for Bis solutions at a low concentration. In the case of PEGDA-Bis mixtures, co-polymerisation is suggested as well. At a sufficiently high radiation dose, the formation of a polymer network was observed for both monomers and their mixture. For this reason a sol-gel analysis for PEGDA and Bis was performed gravimetrically and a proposition of an alternative to this method employing a nuclear magnetic resonance technique is made. The two monomers were used for preparation of 3D polymer gel dosimeters having the acronyms PABIG and PABIG nx. The latter is presented for the first time in this work and is a type of the formerly established PABIG polymer gel dosimeter. The elementary characteristics of the new composition are presented, underlining the ease of its preparation, low dose threshold, and slightly increased sensitivity but lower quasi-linear range of dose response in comparison to PABIG.

Kozicki, Marek

2011-12-01

349

Automated measurement system employing eddy currents to adjust probe position and determine metal hardness  

DOEpatents

A system for measuring the hardness of cartridge cases employs an eddy current probe for inducing and sensing eddy currents in each cartridge case. A first component of the sensed signal is utilized in a closed loop system for accurately positioning the probe relative to the cartridge case both in the lift off direction and in the tangential direction, and a second component of the sensed signal is employed as a measure of the hardness. The positioning and measurement are carried out under closed loop microprocessor control facilitating hardness testing on a production line basis.

Prince, James M. (Kennewick, WA); Dodson, Michael G. (Richland, WA); Lechelt, Wayne M. (Benton City, WA)

1989-01-01

350

Automated measurement system employing eddy currents to adjust probe position and determine metal hardness  

DOEpatents

A system for measuring the hardness of cartridge cases employs an eddy current probe for inducing and sensing eddy currents in each cartridge case. A first component of the sensed signal is utilized in a closed loop system for accurately positioning the probe relative to the cartridge case both in the lift off direction and in the tangential direction, and a second component of the sensed signal is employed as a measure of the hardness. The positioning and measurement are carried out under closed loop microprocessor control facilitating hardness testing on a production line basis. 14 figs.

Prince, J.M.; Dodson, M.G.; Lechelt, W.M.

1989-07-18

351

Enhanced Low Dose Rate Effects in Bipolar Circuits: A New Hardness Assurance Problem for NASA  

NASA Technical Reports Server (NTRS)

Many bipolar integrated circuits are much more susceptible to ionizing radiation at low dose rates than they are at high dose rates typically used for radiation parts testing. Since the low dose rate is equivalent to that seen in space, the standard lab test no longer can be considered conservative and has caused the Air Force to issue an alert. Although a reliable radiation hardness assurance test has not yet been designed, possible mechanisms for low dose rate enhancement and hardness assurance tests are discussed.

Johnston, A.; Barnes, C.

1995-01-01

352

Radiation microscope for SEE testing using GeV ions.  

SciTech Connect

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.

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

2009-09-01

353

Hard Photodisintegration of 3He  

NASA Astrophysics Data System (ADS)

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.

Granados, Carlos

2011-02-01

354

Weld cladding of hard surfaces  

NASA Astrophysics Data System (ADS)

A literature study about clad welding of hard surfaces on steel is performed. The purpose was to see what kind of methods are mainly used, and particular attention is paid to clad welding of rolls. The main impression from this study is that several methods are in use. Some of these must be considered as 'too exotic' for the aim of the program, such as laser build-up welding. However, clad welding of hard surfaces to rolls is widely used around the world, and there is no need for particularly advanced welding methods to perform the work. The welding consumables and the way the welding is carried out is of more important character. The report will give some comments to this, and hopefully will give a short review of the current technology in this field.

Habrekke, T.

1993-02-01

355

Hard Disk PVT System Model  

NSDL National Science Digital Library

The Hard Disk PVT System simulates a two-dimensional system of particles confined between a thermal reservoir and a piston. This computer model is designed to study the equation of state for hard disks without other interactions. Slow-moving particles are color-coded as blue and fast particles are color-coded as yellow. Users can set the initial particle energy, the initial particle separation, and the thermal reservoir temperature Tr. The thermal conductivity parameter ? determines the probability that a collision with the thermal wall will affect (thermalize) the colliding particle. If the conductivity is one, the particle velocity after a reservoir collision is set according to Maxwell-Boltzmann statistics. If the conductivity is zero, all reservoir collisions are elastic and the internal energy E of the system is conserved.   Particles in this model have unit mass and interact through contact forces. Collision times are computed analytically because particles and pistons move with constant velocity between collisions. The time evolution algorithm advances the particle and piston positions from collision to collision until the requested time step ?t is achieved. The time evolution is then paused, data is accumulated, and the screen is redrawn. The Hard Disk PVT model is a supplemental simulation for the article "Pressure Oscillations in Adiabatic Compression" by Roland Stout in The Physics Teacher 49(5), 280-281 (2011) and has been approved by the author and The Physics Teacher editor. The model was developed using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_stp_hd_HardDiskPVTSystem.jar file will run the program if Java is installed.

Christian, Wolfgang

2011-03-12

356

A Dynamic Hard Sphere Model  

Microsoft Academic Search

A simple two-dimensional model, in which uniform hard spheres are made to move steadily and apparently nearly at random, is described. At low sphere density the model exhibits ``gas-like'' behavior. As the density is increased the behavior becomes more ``liquid-like'' and then ``crystallization'' occurs. Many dynamic atomic phenomena, believed to occur in the gas, liquid, or solid state, are illustrated

D. Turnbull; R. L. Cormia

1960-01-01

357

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 ...

358

Hard scattering and QCD Fundamentals at RHIC  

E-print Network

In 1998, at the 4th QCD workshop, Rolf Baier asked me whether jets could be measured in Au+Au collisions because he had a prediction of a QCD medium-effect (energy loss via soft gluon radiation induced by multiple scattering) on color-charged partons traversing a hot-dense-medium composed of screened color-charges. I reviewed the possibilities in a talk explaining that there was a general consensus that for Au+Au central collisions at $\\sqrt{s_{NN}}=200$ GeV, leading particles are the only way to find jets because of the large particle density. The good news was that hard-scattering in p-p collisions was originally observed by the method of leading particles and that these techniques could be used to study hard-scattering and jets in Au+Au collisions. Notably, I described ``How everything you want to know about jets can be found using 2-particle correlations''. In fact, the predicted ``jet quenching'' and other new phenomena were discovered by this method. However, this past year, I had to soften the statement to {\\em almost everything} because we found by explicit calculation in PHENIX that the away-side two-particle correlation $p_{T_a}$ spectrum from a $\\pi^0$ trigger with $p_{T_t}$ is not sensitive to the fragmentation function--overturning a belief dating from the seminal paper of Feynman, Field and Fox in 1977. A new formula was derived which showed that the shape of the $p_{T_a}$ spectrum depends only on the power $n$ of the parton invariant cross section so that NLO pQCD calculations of the two particle away-side correlations are, in fact, less sensitive to the shape of the fragmentation function than calculations of the inclusive $\\pi^0$ cross section.

M. J. Tannenbaum

2008-06-02

359

Radiation-Hardened Solid-State Drive  

NASA Technical Reports Server (NTRS)

A method is provided for a radiationhardened (rad-hard) solid-state drive for space mission memory applications by combining rad-hard and commercial off-the-shelf (COTS) non-volatile memories (NVMs) into a hybrid architecture. The architecture is controlled by a rad-hard ASIC (application specific integrated circuit) or a FPGA (field programmable gate array). Specific error handling and data management protocols are developed for use in a rad-hard environment. The rad-hard memories are smaller in overall memory density, but are used to control and manage radiation-induced errors in the main, and much larger density, non-rad-hard COTS memory devices. Small amounts of rad-hard memory are used as error buffers and temporary caches for radiation-induced errors in the large COTS memories. The rad-hard ASIC/FPGA implements a variety of error-handling protocols to manage these radiation-induced errors. The large COTS memory is triplicated for protection, and CRC-based counters are calculated for sub-areas in each COTS NVM array. These counters are stored in the rad-hard non-volatile memory. Through monitoring, rewriting, regeneration, triplication, and long-term storage, radiation-induced errors in the large NV memory are managed. The rad-hard ASIC/FPGA also interfaces with the external computer buses.

Sheldon, Douglas J.

2010-01-01

360

Radiation effects microscopy for failure analysis of microelectronic devices.  

SciTech Connect

Microelectronic devices in satellites and spacecraft are exposed to high energy cosmic radiation. Furthermore, Earth-based electronics can be affected by terrestrial radiation. The radiation causes a variety of Single Event Effects (SEE) that can lead to failure of the devices. High energy heavy ion beams are being used to simulate both the cosmic and terrestrial radiation to study radiation effects and to ensure the reliability of electronic devices. Broad beam experiments can provide a measure of the radiation hardness of a device (SEE cross section) but they are unable to pinpoint the failing components in the circuit. A nuclear microbeam is an ideal tool to map SEE on a microscopic scale and find the circuit elements (transistors, capacitors, etc.) that are responsible for the failure of the device. In this paper a review of the latest radiation effects microscopy (REM) work at Sandia will be given. Different SEE mechanisms (Single Event Upset, Single Event Transient, etc.) and the methods to study them (Ion Beam Induced Charge (IBIC), Single Event Upset mapping, etc.) will be discussed. Several examples of using REM to study the basic effects of radiation in electronic devices and failure analysis of integrated circuits will be given.

Doyle, Barney Lee; Dodd, Paul Emerson; Vizkelethy, Gyorgy; Shaneyfelt, Marty Ray; Brice, David Kenneth; Schwank, James Ralph

2004-10-01

361

Computational Modeling Develops Ultra-Hard Steel  

NASA Technical Reports Server (NTRS)

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.

2007-01-01

362

Heritability of juvenile growth for the hard clam Mercenaria mercenaria  

Microsoft Academic Search

The heritability of juvenile growth in the hard clamMercenaria mercenaria (L.) sampled from Wellfleet Harbor, USA, in 1987, was analyzed in two experiments using standard quantitative genetic methods. In the first experiment, culture density was not controlled and was found to have a significant impact upon the non-additive genetic component of growth, possibly through genotype-environment correlation. Variable clam density appeared

P. D. Rawson; T. J. Hilbish

1990-01-01

363

COMPONENTS OF LASER SYSTEMS AND PROCESSES OCCURRING IN THEM: Utilization of competition between counterpropagating waves for modulation and stabilization of the radiation emitted from a ring laser  

NASA Astrophysics Data System (ADS)

Theoretical and experimental investigations were made of the possibility of increasing the efficiency of intracavity modulation and stabilization of the radiation emitted from ring lasers by utilization of the competition between counterpropagating waves. It was established that in the case of solid-state ring lasers one can switch rapidly the direction of counterpropagating waves both in the case of forced mode locking and in the case of single-mode emission without spike transient processes at a relaxation frequency typical of solid-state lasers. An analysis was made of the conditions for significant reduction of the switching time and a method is suggested for achieving this by simultaneous modulation of the amplitude nonreciprocity and of the coupling between counterpropagating waves. It is shown that highly stable unidirectional single-mode operation of a solid-state ring laser can be achieved as a result of weak modulation of the resonator perimeter. Various time dependences of the intensities of counterpropagating waves and stabilization of bidirectional operation of a solid-state ring laser were achieved using a magnetooptic feedback loop.

Kornienko, L. S.; Nani?, O. E.; Shelaev, A. N.

1988-09-01

364

DISTRIBUTED VERIFICATION AND HARDNESS OF DISTRIBUTED APPROXIMATION  

E-print Network

DISTRIBUTED VERIFICATION AND HARDNESS OF DISTRIBUTED APPROXIMATION ATISH DAS SARMA, STEPHAN HOLZER on the hardness of distributed approximation for many classical optimization problems including minimum spanning the previous hardness of approximation bound of Elkin [STOC 2004] as well as the lower bound for (exact) MST

365

Distributed Verification and Hardness of Distributed Approximation  

E-print Network

Distributed Verification and Hardness of Distributed Approximation Atish Das Sarma Google Foundation (BSF). Permission to make digital or hard copies of all or part of this work for personal on the hardness of distributed approxi- mation for many classical optimization problems including minimum spanning

366

Collisions of Nuclei: New Ideas for Hard  

E-print Network

Collisions of Nuclei: New Ideas for Hard Probes Rainer Fries Texas A&M University & RIKEN BNL collisions and hard probes Hadron chemistry and flavor conversions Tomography + development of a new test Equilibration, thermalization Quark Gluon Plasma Non-perturbative dynamics Hard particles (PT > 1 -2GeV): Rare

367

Instrumented hardness testing using a flat punch  

Microsoft Academic Search

Instrumented hardness tests using a flat punch were performed and analysed using an original approach. The quality of the hardness-flow stress correlation using this particular type of indenter is investigated. It is found that some characteristic force values of the instrumented hardness test are very well correlated to yield and tensile strength.

M. Scibetta; E. Lucon; R. Chaouadi; E. van Walle

2003-01-01

368

Artificially soft and hard surfaces in electromagnetics  

Microsoft Academic Search

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

Per-Simon Kildal

1990-01-01

369

Kinetics of hardness evolution during annealing of gamma-irradiated polycarbonate  

SciTech Connect

This study focuses on the evolution in microhardness values that accompany isothermal annealing in gamma-irradiated polycarbonate (PC). Hardness increases with increasing annealing time, temperature, and gamma radiation dose. A model composed of a mixture of first and zero order structure relaxation is proposed to interpret the hardness data. The rate constant data fit the Arrhenius equation, and the corresponding activation energy decreases with increasing dose. The extent of structural relaxation that controls the hardness in post-annealed PC increases with increasing annealing temperature and dose. The model demonstrates that hardness evolution in PC is an endothermic process. By contrast, when the model is applied to irradiated poly(methyl methacrylate) and hydroxyethyl methacrylate copolymer, hardness evolution is an exothermic process.

Yeh, S. H.; Chen, P. Y.; Lee, Sanboh [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Harmon, Julie [Department of Chemistry, University of South Florida, Tampa, Florida 33620-5250 (United States)

2012-12-01

370

Plasticity-induced damage layer is a precursor to wear in radiation-cross-linked UHMWPE acetabular components for total hip replacement. Ultra-high-molecular-weight polyethylene.  

PubMed

The mechanism for the improved wear resistance of cross-linked ultra-high-molecular-weight polyethylene (UHMWPE) remains unclear. This study investigated the effect of cross-linking achieved by gamma irradiation in nitrogen on the tribologic, mechanical, and morphologic properties of UHMWPE. The goal of this study was to relate UHMWPE properties to the wear mechanism in acetabular-bearing inserts. Wear simulation of acetabular liners was followed by detailed characterization of the mechanical behavior and crystalline morphology at the articulating surface. The wear rate was determined to be directly related to the ductility, toughness, and strain-hardening behavior of the UHMWPE. The concept of a plasticity-induced damage layer is introduced to explain the near-surface orientation of the crystalline lamellae observed in the wear-tested acetabular liners. Cross-linking reduces abrasive wear of acetabular components by substantially reducing--but not eliminating--the plasticity-induced damage layer that precedes abrasive wear. PMID:10475563

Edidin, A A; Pruitt, L; Jewett, C W; Crane, D J; Roberts, D; Kurtz, S M

1999-08-01

371

Hard X-ray emission of the Earth's atmosphere: Monte Carlo simulations  

Microsoft Academic Search

We perform Monte Carlo simulations of cosmic ray-induced hard X-ray radiation from the Earth's atmosphere. We find that the shape of the spectrum emergent from the atmosphere in the energy range 25-300 keV is mainly determined by Compton scatterings and photoabsorption, and is almost insensitive to the incident cosmic ray spectrum. We provide a fitting formula for the hard X-ray

S. Sazonov; E. Churazov; R. Sunyaev; M. Revnivtsev

2007-01-01

372

Hard body amphiphiles at a hard wall JOSEPH M. BRADER1y  

E-print Network

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

Ott, Albrecht

373

Hardness Standardization Our objective is to standardize and improve hardness measurement  

E-print Network

Hardness Standardization METALS Our objective is to standardize and improve hardness measurement both in the U.S. and internationally. NIST is the U.S. National Metrology Institute (NMI) for hardness, and as such, is responsible for traceability in hardness measurements. Objective Impact and Customers

374

Hard Questions 1 When Hard Questions are Asked: Evaluating Writing Centers  

E-print Network

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

Northern British Columbia, University of

375

The Hard Problem of Cooperation  

PubMed Central

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

Eriksson, Kimmo; Strimling, Pontus

2012-01-01

376

Measurements of the hard-x-ray reflectivity of iridium  

SciTech Connect

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.

Romaine, S.; Bruni, R.; Gorenstein, P.; Zhong, Z

2007-01-10

377

Different progenitors of short hard gamma-ray bursts  

E-print Network

We consider the spatial offsets of short hard gamma-ray bursts (SHBs) from their host galaxies. We show that all SHBs with extended duration soft emission components lie very close to their hosts. We suggest that NS-BH binary mergers offer a natural explanation for the properties of this extended duration/low offset group. SHBs with large offsets have no observed extended emission components and are less likely to have an optically detected afterglow, properties consistent with NS-NS binary mergers occurring in low density environments.

Eleonora Troja; Andrew R. King; Paul T. O'Brien; Nicola Lyons; Giancarlo Cusumano

2007-11-19

378

Hard Core entropy: lower bounds  

E-print Network

We establish lower bounds for the entropy of the Hard Core Model on a few 2d lattices $\\scriptstyle {\\rm {\\bf L}}.$ In this model the allowed configurations inside $\\scriptstyle \\{0,1\\}^{{\\rm {\\bf L}}}$ are the one's in which the nearest neighbor $\\scriptstyle 1$'s are forbidden. Our method which is based on a sequential fill-in scheme is unbiassed and thereby yields in principle arbitrarily good estimates for the topological entropy. The procedure also gives some detailed information on the support of the measure of maximal entropy.

Kari Eloranta

2009-07-23

379

Response of nickel surface to pulsed fusion plasma radiations  

NASA Astrophysics Data System (ADS)

Nickel based alloys are being projected as suitable materials for some components of the next generation fusion reactor because of compatible thermal, electrical and mechanical properties. Pure nickel material is tested here for possibility of similar application purpose. Nickel samples (> 99.5 % purity) are exposed here to plasma radiations produced due to D-D fusion reaction inside an 11.5 kJ plasma focus device. The changes in the physical properties of the nickel surface at microscopic level which in turn change the mechanical properties are analyzed using scanning electron microscope, optical microscope, glancing incident X-ray diffractometer and Vicker's hardness gauge. The results are reported here.

Niranjan, Ram; Rout, R. K.; Srivastava, R.; Chakravarthy, Y.; Patel, N. N.; Alex, P.; Gupta, Satish C.

2014-04-01

380

Estimates of HZE particle contributions to SPE radiation exposures on interplanetary missions  

NASA Technical Reports Server (NTRS)

Estimates of radiation doses resulting from possible HZE (high energy heavy ion) components of Solar Particle Events (SPEs) are presented for crews of manned interplanetary missions. The calculations assume a model spectrum obtained by folding measured solar flare HZE particle abundances with the measured energy spectra of SPE alpha particles. These hypothetical spectra are then transported through aluminum spacecraft shielding. The results, presented as estimates of absorbed dose and dose equivalent, indicate that HZE components by themselves are not a major concern for crew protection but should be included in any overall risk assessment. The predictions are found to be sensitive to the assumed spectral hardness parameters.

Townsend, L. W.; Cucinotta, F. A.; Wilson, J. W.; Bagga, R.

1994-01-01

381

Automated laser fabrication of cemented carbide components  

NASA Astrophysics Data System (ADS)

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.

Paul, C. P.; Khajepour, A.

2008-07-01

382

Leptonic tensor for hard photon emission in annihilation channel.Dirac tensor with heavy photon  

E-print Network

For the large-angles hard photon emission by initial leptons in process of high energy annihilation of $e^+ e^- \\to $ to hadrons the Dirac tensor is obtained, taking into account the lowest order radiative corrections. The case of large-angles emission of two hard photons by initial leptons is considered. This result is being completed by the kinematics case of collinear hard photons emission as well as soft virtual and real photons and can be used for construction of Monte-Carlo generators.

V. V. Bytev; E. A. Kuraev; E. S. Scherbakova

2011-12-12

383

Possible evidence for beaming in flares from microwave and hard X-ray imaging and spectra  

NASA Technical Reports Server (NTRS)

The magnetic field strength and number of burst-producing energetic electrons are presently deduced for the impulsive phase of a solar flare at microwave wavelengths, with the VLA, and hard X-rays, with the SMM Hard X-ray Burst Spectrometer. The combined data indicate that the number of microwave-emitting electrons is at least three orders of magnitude smaller than the number of thick target electrons producing the hard X-rays; this is suggested to be due to the high beaming and inefficient radiation of gyrosynchrotron emission by comparison with isotropically distributed electrons.

Schmahl, E. J.; Kundu, M. R.; Dennis, B. R.

1986-01-01

384

Hardness correlation for uranium and its alloys  

SciTech Connect

The hardness of 16 different uranium-titanium (U-Ti) alloys was measured on six (6) different hardness scales (R/sub A/, R/sub B/, R/sub C/, R/sub D/, Knoop, and Vickers). The alloys contained between 0.75 and 2.0 wt % Ti. All of the alloys were solutionized (850/sup 0/C, 1 h) and ice-water quenched to produce a supersaturated martensitic phase. A range of hardnesses was obtained by aging the samples for various times and temperatures. The correlation of various hardness scales was shown to be virtually identical to the hardness-scale correlation for steels. For more-accurate conversion from one hardness scale to another, least-squares-curve fits were determined for the various hardness-scale correlations. 34 figures, 5 tables.

Humphreys, D L; Romig, Jr, A D

1983-03-01

385

Mn incorporation into the GaAs lattice investigated by hard x-ray photoelectron spectroscopy and diffraction  

SciTech Connect

Photoelectron spectroscopy and diffraction have been used to investigate structural changes during the annealing process of Ga{sub 1-x}Mn{sub x}As samples. Hard x-ray radiation helped in observing photoelectron core-level spectra and electron diffraction from the bulk underlying the oxidized surface layer. High electron-energy resolution enabled us to separate the components due to substitutional and interstitial Mn atoms in the intrinsic Mn 2p{sub 3/2} photoemission profile, resulting in two peaks at 638.8 and 639.5 eV binding energy, respectively. The peaks display the known characteristic behavior after annealing, that is, an almost complete reduction of the interstitial component and preservation of the substitutional component. In the photoelectron diffraction, a sensitivity of high-energy polar plots to the incorporation sites of photoemitting atoms into the atomic lattice has been shown. As a consequence, the experimental polar plots from substitutional and interstitial Mn atoms, which are supported theoretically, show characteristic features that provide structural information. From the similarities and differences of the polar plots for Mn and Ga, we have confirmed the assignment of components within the intrinsic part of the photoemission Mn 2p{sub 3/2} signal suggested by photoelectron spectroscopy.

Bartos, I.; Cukr, M.; Jiricek, P. [Institute of Physics, Academy of Sciences of the Czech Republic, CZ-162 53 Prague 6 (Czech Republic); Pis, I. [Charles University, Faculty of Mathematics and Physics, Department of Surface and Plasma Science, CZ-180 00 Prague 8 (Czech Republic); Kobata, M.; Kobayashi, K. [National Institute for Materials Science, SPring-8, Hyogo (Japan); Sugiyama, T.; Ikenaga, E. [Japan Synchrotron Radiation Research Institute, SPring-8, Hyogo (Japan)

2011-06-15

386

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

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. PMID:23088412

Moeller, Ralf; Reitz, Günther; Li, Zuofeng; Klein, Stuart; Nicholson, Wayne L

2012-11-01

387

Probing Strangeness in Hard Processes  

E-print Network

Since the discovery of strangeness almost five decades ago, interest in this degree of freedom has grown up and now its investigation spans the scales from quarks to nuclei. Measurements with identified strange hadrons can provide important information on several hot topics in hadronic physics: the strange distribution and fragmentation functions, the nucleon tomography and quark orbital momentum, accessible through the study of the {\\it generalized} parton distribution and the {\\it transverse momentum dependent} parton distribution functions, the quark hadronization in the nuclear medium, the hadron spectroscopy and the search for exotic mesons. The CLAS12 large acceptance spectrometer in Hall B at the Jefferson Laboratory upgraded with a RICH detector together with the 12 GeV CEBAF high intensity, high polarized electron beam can open new possibilities to study strangeness in hard processes allowing breakthroughs in all those areas. This paper summarizes the physics case for a RICH detector for CLAS12. Many topics have been intensively discussed at the International Workshop "Probing Strangeness in Hard Processes" (PSHP2010) \\cite{PSHP-workshop} held in Frascati, Italy in October 2010. The authors of this papers like to thank all speakers and participants of the workshop for their contribution and very fruitful discussion.

H. Avakian; M. Battaglieri; E. Cisbani; M. Contalbrigo; U. D'Alesio; R. De Leo; R. Devita; P. Di Nezza; D. Hasch; V. Kubarovsky; M. Mirazita; M. Osipenko; L. Pappalardo; P. Rossi

2012-02-09

388

Hard and Soft Safety Verifications  

NASA Technical Reports Server (NTRS)

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.

Wetherholt, Jon; Anderson, Brenda

2012-01-01

389

The New Hard X-ray Mission  

NASA Astrophysics Data System (ADS)

The Italian New Hard X-ray Mission (NHXM) is an evolution of the HEXIT-Sat concept, extending up to 80 keV the fine imaging capability today available only at E<10 keV, with the further addition of photoelectric imaging polarimetry. NHXM consists of four identical mirrors, with a 10 m focal length, achieved after launch by means of a deployable structure. Three of the four telescopes will have at their focus three identical spectro-imaging cameras, while a X-ray imaging polarimeter will be placed at the focus of the fourth. In order to ensure a low and stable background, NHXM will be place on a low Earth equatorial orbit. NHXM will provide a real breakthrough on a number of hot astrophysical issues, broadly falling under two main topics: i) censing the black holes in the Universe and probing the physics of accretion in the most diverse conditions; ii) investigating the particle acceleration mechanisms at work in different contexts, and the effects of radiative transfer in highly magnetized plasmas and strong gravitational fields.

Pareschi, Giovanni; Tagliaferri, Gianpiero; Argan, Andrea; Bellazzini, Ronaldo; Catalano, Osvaldo; Costa, Enrico; Cusumano, Giancarlo; Fiore, Fabrizio; Fiorini, Carlo; Malaguti, Giuseppe; Matt, Giorgio; Mereghetti, Sandro; Micela, Giuseppina; Perola, Giuseppe Cesare; Villa, Gabriele

2010-07-01

390

Pulsar Wind Nebulae from Radio to Hard X-rays  

NASA Astrophysics Data System (ADS)

When a pulsar spins down, the vast majority of its rotational energy is carried away by the relativistic wind. The consequent interaction of the wind with the surrounding environment results in a synchrotron nebula, known as a pulsar wind nebula (PWN), which emits broad-band radiation across the entire electromagnetic spectrum, from radio to X-rays, to gamma-rays. Due to the long synchrotron lifetime, radio emission of a PWN can act as a direct calorimeter to reveal the integrated history of a system. At the other extreme of the synchrotron spectrum, hard X-rays trace the most energetic particles, directly probing the acceleration process. Combining observations from both regimes can provide important insights into the physical conditions and evolution of PWNe. In this talk, I will review the PWN physics and recent observational results. Prospects on upcoming hard X-ray missions, including NuSTAR, Astrosat, and Astro-H will also be discussed.

Ng, Stephen C.-Y.

2012-07-01

391

Polarization effects on hard target calibration of lidar systems.  

PubMed

The theory of hard target calibration of lidar backscatter data, including laboratory measurements of the pertinent target reflectance parameters, is extended to include the effects of polarization of the transmitted and received laser radiation. The bidirectional reflectance-distribution function model of reflectance is expanded to a 4 x 4 matrix allowing Mueller matrix and Stokes vector calculus to be employed. Target reflectance parameters for calibration of lidar backscatter data are derived for various lidar system polarization configurations from integrating sphere and monostatic reflectometer measurements. It is found that correct modeling of polarization effects is mandatory for accurate calibration of hard target reflectance parameters and, therefore, for accurate calibration of lidar backscatter data. PMID:20454226

Kavaya, M J

1987-03-01

392

Hard X-ray emission of Sco X-1  

NASA Astrophysics Data System (ADS)

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.

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

2014-12-01

393

Nanomechanics of hard films on compliant substrates.  

SciTech Connect

Development of flexible thin film systems for biomedical, homeland security and environmental sensing applications has increased dramatically in recent years [1,2,3,4]. These systems typically combine traditional semiconductor technology with new flexible substrates, allowing for both the high electron mobility of semiconductors and the flexibility of polymers. The devices have the ability to be easily integrated into components and show promise for advanced design concepts, ranging from innovative microelectronics to MEMS and NEMS devices. These devices often contain layers of thin polymer, ceramic and metallic films where differing properties can lead to large residual stresses [5]. As long as the films remain substrate-bonded, they may deform far beyond their freestanding counterpart. Once debonded, substrate constraint disappears leading to film failure where compressive stresses can lead to wrinkling, delamination, and buckling [6,7,8] while tensile stresses can lead to film fracture and decohesion [9,10,11]. In all cases, performance depends on film adhesion. Experimentally it is difficult to measure adhesion. It is often studied using tape [12], pull off [13,14,15], and peel tests [16,17]. More recent techniques for measuring adhesion include scratch testing [18,19,20,21], four point bending [22,23,24], indentation [25,26,27], spontaneous blisters [28,29] and stressed overlayers [7,26,30,31,32,33]. Nevertheless, sample design and test techniques must be tailored for each system. There is a large body of elastic thin film fracture and elastic contact mechanics solutions for elastic films on rigid substrates in the published literature [5,7,34,35,36]. More recent work has extended these solutions to films on compliant substrates and show that increasing compliance markedly changes fracture energies compared with rigid elastic solution results [37,38]. However, the introduction of inelastic substrate response significantly complicates the problem [10,39,40]. As a result, our understanding of the critical relationship between adhesion, properties, and fracture for hard films on compliant substrates is limited. To address this issue, we integrated nanomechanical testing and mechanics-based modeling in a program to define the critical relationship between deformation and fracture of nanoscale films on compliant substrates. The approach involved designing model film systems and employing nano-scale experimental characterization techniques to isolate effects of compliance, viscoelasticity, and plasticity on deformation and fracture of thin hard films on substrates that spanned more than two orders of compliance magnitude exhibit different interface structures, have different adhesion strengths, and function differently under stress. The results of this work are described in six chapters. Chapter 1 provides the motivation for this work. Chapter 2 presents experimental results covering film system design, sample preparation, indentation response, and fracture including discussion on the effects of substrate compliance on fracture energies and buckle formation from existing models. Chapter 3 describes the use of analytical and finite element simulations to define the role of substrate compliance and film geometry on the indentation response of thin hard films on compliant substrates. Chapter 4 describes the development and application of cohesive zone model based finite element simulations to determine how substrate compliance affects debond growth. Chapter 5 describes the use of molecular dynamics simulations to define the effects of substrate compliance on interfacial fracture of thin hard tungsten films on silicon substrates. Chapter 6 describes the Workshops sponsored through this program to advance understanding of material and system behavior.

Reedy, Earl David, Jr. (Sandia National Laboratories, Albuquerque, NM); Emerson, John Allen (Sandia National Laboratories, Albuquerque, NM); Bahr, David F. (Washington State University, Pullman, WA); Moody, Neville Reid; Zhou, Xiao Wang; Hales, Lucas (University of Minnesota, Minneapolis, MN); Adams, David Price (Sandia National Laboratories, Albuquerque, NM); Yeager,John (Washington State University, Pullman, WA); Nyugen, Thao D. (Johns Hopkins University, Baltimore, MD); Corona, Edmundo (Sandia National Laboratories, Albuquerque, NM); Kennedy, Marian S. (Clemson University, Clemson, SC); Cordill, Megan J. (Erich Schmid Institute, Leoben, Austria)

2009-09-01

394

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

PubMed

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

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

2014-04-28

395

Probing Strangeness in Hard Processes  

E-print Network

Since the discovery of strangeness almost five decades ago, interest in this degree of freedom has grown up and now its investigation spans the scales from quarks to nuclei. Measurements with identified strange hadrons can provide important information on several hot topics in hadronic physics: the strange distribution and fragmentation functions, the nucleon tomography and quark orbital momentum, accessible through the study of the {\\it generalized} parton distribution and the {\\it transverse momentum dependent} parton distribution functions, the quark hadronization in the nuclear medium, the hadron spectroscopy and the search for exotic mesons. The CLAS12 large acceptance spectrometer in Hall B at the Jefferson Laboratory upgraded with a RICH detector together with the 12 GeV CEBAF high intensity, high polarized electron beam can open new possibilities to study strangeness in hard processes allowing breakthroughs in all those areas. This paper summarizes the physics case for a RICH detector for CLAS12. Many...

Avakian, H; Cisbani, E; Contalbrigo, M; D'Alesio, U; De Leo, R; Devita, R; Di Nezza, P; Hasch, D; Mirazita, M; Osipenko, M; Pappalardo, L; Rossi, P

2012-01-01

396

Hard-gapped Holographic Superconductors  

E-print Network

In this work we discuss the zero temperature limit of a "p-wave" holographic superconductor. The bulk description consists of a non-Abelian SU(2) gauge fields minimally coupled to gravity. We numerically construct the zero temperature solution which is the gravity dual of the superconducting ground state of the "p-wave" holographic superconductors. The solution is a smooth soliton with zero horizon size and shows an emergent conformal symmetry in the IR. We found the expected superconducting behavior. Using the near horizon analysis we show that the system has a "hard gap" for the relevant gauge field fluctuations. At zero temperature the real part of the conductivity is zero for an excitation frequency less than the gap frequency. This is in contrast with what has been observed in similar scalar- gravity-gauge systems (holographic superconductors). We also discuss the low but finite temperature behavior of our solution.

Pallab Basu; Jianyang He; Anindya Mukherjee; Hsien-Hang Shieh

2009-11-26

397

FDC, rapid fabrication of structural components  

Microsoft Academic Search

Solid freeform fabrication (SFF) is used to make 3-D components directly from computer-aided design (CAD) files. Many SFF techniques have been developed to fabricate parts and prototypes from CAD without hard tooling, dies or molds. Most of these techniques have been commercialized for fabrication of polymer and plastic parts for design verification and form and fit. Other SFF techniques are

M. K. Agarwala; A. Bandyopadhyay; R. van Weeren; A. Safari; S. C. Danforth; N. A. Langrana; V. R. Jamalabad; P. J. Whalen

1996-01-01

398

ELECTRODEPOSITION OF NANOCRYSTALLINE COBALT ALLOY COATINGS AS A HARD CHROME ALTERNATIVE  

Microsoft Academic Search

Replacement of hard chromium (Cr) plating in aircraft manufacturing activities and maintenance depots is a high priority for the U.S. Department of Defense. Hard Cr plating is a critical process that is used extensively within military aircraft maintenance depots for applying wear and\\/or corrosion resistant coatings to various aircraft components and for general re-build of worn or corroded parts during

Ruben A. Prado; Diana Facchini; Neil Mahalanobis; Francisco Gonzalez; Gino Palumbo

399

Shoe midsole hardness, sex and age effects on lower extremity kinematics during running.  

PubMed

Previous studies investigating the effects of shoe midsole hardness on running kinematics have often used male subjects from within a narrow age range. It is unknown whether shoe midsole hardness has the same kinematic effect on male and female runners as well as runners from different age categories. As sex and age have an effect on running kinematics, it is important to understand if shoe midsole hardness affects the kinematics of these groups in a similar fashion. However, current literature on the effects of sex and age on running kinematics are also limited to a narrow age range distribution in their study population. Therefore, this study tested the influence of three different midsole hardness conditions, sex and age on the lower extremity kinematics during heel-toe running. A comprehensive analysis approach was used to analyze the lower-extremity kinematic gait variables for 93 runners (male and female) aged 16-75 years. Participants ran at 3.33±0.15 m/s on a 30 m-long runway with soft, medium and hard midsoles. A principal component analysis combined with a support vector machine showed that running kinematics based on shoe midsole hardness, sex, and age were separable and classifiable. Shoe midsole hardness demonstrated a subject-independent effect on the kinematics of running. Additionally, it was found that age differences affected the more dominant movement components of running compared to differences due to the sex of a runner. PMID:22507350

Nigg, Benno M; Baltich, Jennifer; Maurer, Christian; Federolf, Peter

2012-06-01

400

Analysis of hard carbon for lithium-ion batteries by hard X-ray photoelectron spectroscopy  

NASA Astrophysics Data System (ADS)

Non-graphitizable carbon (hard carbon) as a negative electrode material for lithium-ion batteries is investigated by X-ray photoelectron spectroscopy, and hard X-ray photoelectron spectroscopy (HX-PES). HX-PES spectra have peaks of both the solid electrolyte interphase on the hard carbon surface and the hard carbon itself. The change in spectrum with state of charge is observed by HX-PES. Hard carbon has two types of lithium insertion site; between graphene sheets and into nano-scale voids. These spectroscopic results are consistent with the lithium insertion mechanism into hard carbon.

Hori, Hironobu; Shikano, Masahiro; Kobayashi, Hironori; Koike, Shinji; Sakaebe, Hikari; Saito, Yoshiyasu; Tatsumi, Kuniaki; Yoshikawa, Hideki; Ikenaga, Eiji

2013-11-01

401

Zone Plates for Hard X-Ray FEL Radiation  

SciTech Connect

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.

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

402

A High Performance Radiation-Hard Field Programmable Analog Array  

Microsoft Academic Search

Abstract – While interest, availability and use of FPAAs have grown, FPAAs still have not achieved the same,success as FPGAs in the digital domain. This results from several factors,including the lack of CAD tools, small circuit density, small bandwidth and layout dependent,noise figures. These factors are all related toeach other, making the design of a high performance,FPAA a multi-dimensional ,problem.

Ji Luo; Joseph B. Bernstein; J. Ari Tuchman; Hu Huang; Kuan-jung Chung; Anthony L. Wilson

2004-01-01

403

Radiation-hard semiconductor detectors for SuperLHC  

Microsoft Academic Search

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

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

404

Space Radiation Effects and Hardness Assurance for Linear Integrated Circuits  

NASA Technical Reports Server (NTRS)

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.

Johnston, A. H.

2000-01-01

405

Radiation damage  

E-print Network

a) Radiation damage in organic materials. This series of lectures will give an overview of radiation effects on materials and components frequently used in accelerator engineering and experiments. Basic degradation phenomena will be presented for organic materials with comprehensive damage threshold doses for commonly used rubbers, thermoplastics, thermosets and composite materials. Some indications will be given for glass, scintillators and optical fibres. b) Radiation effects in semiconductor materials and devices. The major part of the time will be devoted to treat radiation effects in semiconductor sensors and the associated electronics, in particular displacement damage, interface and single event phenomena. Evaluation methods and practical aspects will be shown. Strategies will be developed for the survival of the materials under the expected environmental conditions of the LHC machine and detectors. I will describe profound revolution in our understanding of black holes and their relation to quantum me...

Heijne, Erik H M; CERN. Geneva

1998-01-01

406

JPL Radiation Effects Facilities  

NASA Technical Reports Server (NTRS)

Radiation Effects Group investigates the effects of space radiation on present and future microelectronic and optoelectronic technologies, evaluate the risk of using them in specific space missions, and recommend component and design techniques for JPL and NASA programs to reduce reliability risk from space radiation.

Thorbourn, Dennis

2013-01-01

407

Black hole transient during transition from hard to soft state  

NASA Astrophysics Data System (ADS)

We propose a ToO observation of a transient black-hole candidate, either known or unknown, during its transition from hard to soft state. This transition, which takes place at high flux levels, encompasses marked changes in the properties of the accretion flow and it includes the time at which the ejection of an accelerating relativistic jet stops abruptly. The study of the soft spectral component as well as the behaviour of the iron line is important for our understanding of the accretion disc during state transition. We would like to investigate in particular the process responsible for the disappearance of the variability in the soft energy band, which has been detected in the hard state with XMM-Newton, but is absent in the soft state.

Stiele, Holger

2013-10-01

408

Hardness and Tensile Strength of Multifilamentary Metal-matrix Composite Superconductors for the Large Hadron Collider (LHC)  

E-print Network

Conventional indentation hardness measurements to obtain load independent Vickers hardness values for the different phases in multifilamentary superconducting (SC) wires are described. The concept of composite hardness is validated for a binary metal-matrix metal-filament Nb-Ti/Cu composite wire. The tensile materials properties of the individual wire components are estimated from their indentation hardness. The potential and limitations of this approach are critically discussed, based on a comparison with tensile test results obtained for wires and extracted Nb-Ti filaments.

Scheuerlein, C; Leroy, D; Oberli, L; Rehmer, B

2007-01-01

409

Non-destructive component separation using infrared radiant energy  

DOEpatents

A method for separating a first component and a second component from one another at an adhesive bond interface between the first component and second component. Typically the method involves irradiating the first component with infrared radiation from a source that radiates substantially only short wavelengths until the adhesive bond is destabilized, and then separating the first component and the second component from one another. In some embodiments an assembly of components to be debonded is placed inside an enclosure and the assembly is illuminated from an IR source that is external to the enclosure. In some embodiments an assembly of components to be debonded is simultaneously irradiated by a multi-planar array of IR sources. Often the IR radiation is unidirectional. In some embodiments the IR radiation is narrow-band short wavelength infrared radiation.

Simandl, Ronald F. (Knoxville, TN); Russell, Steven W. (Knoxville, TN); Holt, Jerrid S. (Knoxville, TN); Brown, John D. (Harriman, TN)

2011-03-01

410

Statistical Mechanics of One-Dimensional Multicomponent Gases of Molecules with Hard Cores and Weak Long-Range Interactions  

Microsoft Academic Search

The models of one-dimensional r-component gas of molecules with hard cores of different diameters sigma1, sigma2, \\\\cdots, sigmar (sigmai{=}diameter of the hard core for the i-th component) and with attractive interaction potentials -2aij\\/L (aij{=}positive constant, i, j{=}1, 2, \\\\cdots, r, L{=}length of the vessel of the gas, L-->?) or with attractive interaction potentials -aijgammae-gamma R (aij{=}positive constant, i, j{=}1, 2,

Kazuyosi Ikeda

1986-01-01

411

The Elusive Soft Emission from Hard X-ray Symbiotic System RT Cru  

NASA Astrophysics Data System (ADS)

RT Cru is a fascinating member of a new class of hard X-ray emitting symbiotic binaries showing X-ray emission extending to over 50keV. While its hard X-ray emission has been studied in detail, the soft component of the spectrum, including flares, remains elusive, since previous observations have focused on the high-energy regime. We propose Chandra HRC-S/LETG observations to determine the spatial, spectral, and temporal characteristics of the source of the soft X-ray emission with a goal to establish the origin of the soft component, and determine whether and how it is tied to the hard component. Determining the origin of the soft emission is a crucial piece of the puzzle to understanding the geometry, energetics, and the environment of WD accretion in this class of symbiotic systems.

Karovska, Margarita

2014-09-01

412

Studies of the Performance of Radiatino Hard GaAs Photodetectors  

NASA Astrophysics Data System (ADS)

Gallium Arsenide (GaAs) photodetectors are a type of semiconducting photodetector that should be able to withstand much higher levels of radiation than commonly used silicon photomultipliers (SIPMs). At the University of Virginia we are characterizing GaAs devices as compared to SIPMs by studying the I/V curve in breakdown region, the breakdown voltage, dark noise, and response to photons. Measurements of single photon avalanche diodes (SPADs) and PMC (multiple SPAD chips) are being made focusing on the breakdown region for hardness tests. The SPADs and PMCs will be exposed to high levels of radiation in test beam environments so that post-irradiation performance can be characterized as well. Ultimately GaAs photodetectors could prove to be effective radiation-hard detectors with applications in high radiation environments like those found at the upgraded high-luminosity Large Hadron Collider (LHC).

Goodell, Joseph

2011-10-01

413

Phase diagram of hard tetrahedra.  

PubMed

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

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

2011-11-21

414

Effect of substrate hardness and film structure on indentation depth criteria for film hardness testing  

Microsoft Academic Search

The indentation depth limits for the Vickers microhardness testing of amorphous, polycrystalline, multilayer and single crystal coatings were investigated. The coating\\/substrate hardness ratio was varied in the range from 0.01 to 20. The critical indentation depth hc, below which the substrate has a negligible effect on the hardness, was estimated from the experimentally obtained hardness versus indentation depth curves. The

Ilze Manika; Janis Maniks

2008-01-01

415

Structure, preparation and properties of refractory compounds and systems (hard materials and hard metals)  

NASA Technical Reports Server (NTRS)

The hardness optimization of cemented carbides is discussed. TaC-based cermets, cermets with low nonmetal/metal ratios, and composites with hard phases formed by the decomposition of Ta carbon-nitrides are described. The optimization of WC hard alloys with a FeCoNi binder, and phase relations in nitride and nitride/metal systems are reported.

Holleck, H.; Thuemmier, F.

1983-01-01

416

Periodically kicked hard oscillators G. A. Cecchi  

E-print Network

Periodically kicked hard oscillators G. A. Cecchi Departamento de Fisica, U.N.L.P.,Argentina D. L for publication 25 November 1992) A model of a hard oscillator with analytic solution is presented. Its behavior. It is shown that the general structure of such an oscillator includes four distinct regions; the outer two

417

Retraction of Hard, Lozano, and Tversky (2006)  

ERIC Educational Resources Information Center

Reports a retraction of "Hierarchical encoding of behavior: Translating perception into action" by Bridgette Martin Hard, Sandra C. Lozano and Barbara Tversky (Journal of Experimental Psychology: General, 2006[Nov], Vol 135[4], 588-608). All authors retract this article. Co-author Tversky and co-author Hard believe that the research results cannot…

Hard, B. M.; Lozano, S. C.; Tversky, B.

2008-01-01

418

Spectral Bounds on General Hard Core Predicates ?  

E-print Network

of functions computable in AC 0 . The above bound on sensitivity is obtained by (lower) bounding the high order(x). A hard core predicate, though a basic primitive, has remarkably potency: { If f is a permutation, a hard of Goldmann and Naslund [2] shows that they cannot, in general, be computed in AC 0 . We strengthen

Russell, Alexander

419

Matrix of Hard and Soft Skills  

NSDL National Science Digital Library

This document was developed by Access Tech Careers to support successful course completion for students with learning disabilities. This matrix displays intersections between hard skills, including reading, writing, oral communication, and math, with soft skills, including critical thinking, teamwork, professionalism, and adaptability. It can help instructors integrate hard and soft skills in course planning.

2012-07-24

420

Multiple Components of the Luminous Compact X-ray Source at the Edge of Holmberg II observed by ASCA and ROSAT  

E-print Network

We report the results of the analysis of ASCA/ROSAT observations of the compact luminous X-ray source found at the edge of the nearby star-forming dwarf galaxy Holmberg II (UGC 4305).Our ASCA spectrum revealed that the X-ray emission extends to the hard band and can be best described by a power-law with a photon spectral index of 1.9. The ASCA spectrum does not fit with a multi-color disk blackbody. The joint ASCA-ROSAT spectrum suggests two components to the spectrum: the hard power-law component and a warm thermal plasma kT~0.3[keV]. An additional absorption over that of our galaxy is required. The wobble correction of the ROSAT HRI image has clearly unveiled the existence of an extended component which amounts to 27+/-5% of the total X-ray emission. These observations indicate that there are more than one component in the X-ray emission. The properties of the point-like component is indicative of an accretion onto an intermediate mass blackhole, unless a beaming is taking place. We argue that the extended component does not come from electron scattering and/or reflection by scattered optically-thick clouds of the central radiation. Possible explanations of this X-ray source include multiple supernova remnants feeding an intermediate-mass blackhole. (abridged)

Takamitsu Miyaji; Ingo Lehmann; Guenther Hasinger

2001-02-28

421

H-alpha and hard X-ray development in two-ribbon flares  

NASA Technical Reports Server (NTRS)

Morphological features of two-ribbon flares have been studied, using simultaneous ISEE-3 hard X-ray records and high-resolution Big Bear H-alpha movies for more than 20 events. Long-lasting and complex hard X-ray bursts are almost invariably found associated with flares of the two-ribbon type. At least three events are found, namely March 31, 1979, April 10, 1980, and July 1, 1980, where the occurrence of individual spikes in hard X-ray radiation coincides with suddenly enhanced H-alpha emission covering the sunspot penumbra. There definitely exist important (greater than or equal to 1 B) two-ribbon flares without significant hard X-ray emission.

Dwivedi, B. N.; Hudson, H. S.; Kane, S. R.; Svestka, Z.

1984-01-01

422

Hardness-based plasticity and fracture model for quench-hardenable boron steel (22MnB5)  

NASA Astrophysics Data System (ADS)

A comprehensive strain hardening and fracture characterization of different grades of boron steel blanks has been performed, providing the foundation for the implementation into the modular material model (MMM) framework developed by Volkswagen Group Research for an explicit crash code. Due to the introduction of hardness-based interpolation rules for the characterized main grades, the hardening and fracture behavior is solely described by the underlying Vickers hardness. In other words, knowledge of the hardness distribution within a hot-formed component is enough to set up the newly developed computational model. The hardness distribution can be easily introduced via an experimentally measured hardness curve or via hardness mapping from a corresponding hot-forming simulation. For industrial application using rather coarse and computationally inexpensive shell element meshes, the user material model has been extended by a necking/post-necking model with reduced mesh-dependency as an additional failure mode. The present paper mainly addresses the necking/post-necking model.

Greve, L.; Eller, T. K.; Medricky, M.; Andres, M.

2013-12-01

423

Hardness-based plasticity and fracture model for quench-hardenable boron steel (22MnB5)  

SciTech Connect

A comprehensive strain hardening and fracture characterization of different grades of boron steel blanks has been performed, providing the foundation for the implementation into the modular material model (MMM) framework developed by Volkswagen Group Research for an explicit crash code. Due to the introduction of hardness-based interpolation rules for the characterized main grades, the hardening and fracture behavior is solely described by the underlying Vickers hardness. In other words, knowledge of the hardness distribution within a hot-formed component is enough to set up the newly developed computational model. The hardness distribution can be easily introduced via an experimentally measured hardness curve or via hardness mapping from a corresponding hot-forming simulation. For industrial application using rather coarse and computationally inexpensive shell element meshes, the user material model has been extended by a necking/post-necking model with reduced mesh-dependency as an additional failure mode. The present paper mainly addresses the necking/post-necking model.

Greve, L., E-mail: lars.greve@volkswagen.de; Medricky, M., E-mail: miloslav.medricky@volkswagen.de; Andres, M., E-mail: miloslav.medricky@volkswagen.de [Volkswagen AG, Letter Box 1777, Wolfsburg, 38436 (Germany); Eller, T. K., E-mail: tom.karl.eller@volkswagen.de [Volkswagen AG, Letter Box 1777, Wolfsburg, 38436, Germany, and University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands)

2013-12-16

424

Hardness of group IVA and IVB nitrides  

NASA Astrophysics Data System (ADS)

The hardnesses of various phases of group IVA and IVB nitrides (M3N4, M=C, Si, Ge, Sn, Ti, Zr or Hf; MN, M=Ti, Zr or Hf) were calculated using the bond electronegativity model for material hardness. The hardnesses of group IV nitrides increase with an increase in their average coordination numbers except for carbon nitrides, for which increasing the average coordination numbers results in a reduction in hardness. We suggest that for light-element compounds, the diamond-like structure represents the hardest one among all possible structures, whereas a high coordination number is generally required for heavy-element compounds to achieve high hardness values. This work provides a useful guide for designing novel nitride materials having excellent mechanical performances.

Li, Keyan; Xue, Dongfeng

2010-05-01

425

Total-dose hardness assurance-testing for CMOS devices in space environment  

Microsoft Academic Search

A practical method for total-dose hardness assurance testing for CMOS devices in a space environment is presented to predict the radiation-induced threshold voltage shift and leakage current. Simple radiation response models for the threshold voltage shift and leakage current are given. The model parameters can be determined by laboratory irradiation testing with Co-60 gamma-rays at a high dose rate. Using

Hiroshi Kamimura; Masaharu Sakagami; Shunsuke Uchida; Masataka Kato

1992-01-01

426

Component-based hardware\\/software co-verification  

Microsoft Academic Search

We present a novel component-based approach to hard- ware\\/software co-verification of embedded systems using model checking. Due to their diverse applications and of- ten strict physical constraints, embedded systems are in- creasingly component-based and include only the neces- sary components for their missions. In our approach, a component model for embedded systems which unifies the concepts of hardware IPs (i.e.,

Fei Xie; Guowu Yang; Xiaoyu Song

2006-01-01

427

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  

E-print Network

[Abridged] We develop and benchmark a fast and easy-to-use effective-opacity formalism for line and continuum radiative transfer in an accelerating two-component clumpy medium. The formalism bridges the limits of optically thin and thick clumps, and is here used to i) design a simple vorosity-modified Sobolev with exact integration (vmSEI) method for 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. 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), but that severe solution degeneracies exist. For an inter-clump density set to 1 % of the mean density, we for O and B supergiants derive upward empirical mass-loss corrections of typically factors of either ~5 or ~50, depending on which of the two applicable solutions...

Sundqvist, J O; Owocki, S P

2014-01-01

428

Semiconductor radiation detector  

DOEpatents

A semiconductor detector for ionizing electromagnetic radiation, neutrons, and energetic charged particles. The detecting element is comprised of a compound having the composition I-III-VI.sub.2 or II-IV-V.sub.2 where the "I" component is from column 1A or 1B of the periodic table, the "II" component is from column 2B, the "III" component is from column 3A, the "IV" component is from column 4A, the "V" component is from column 5A, and the "VI" component is from column 6A. The detecting element detects ionizing radiation by generating a signal proportional to the energy deposited in the element, and detects neutrons by virtue of the ionizing radiation emitted by one or more of the constituent materials subsequent to capture. The detector may contain more than one neutron-sensitive component.

Bell, Zane W. (Oak Ridge, TN); Burger, Arnold (Knoxville, TN)

2010-03-30

429

Effects of total dose irradiation on single-event upset hardness.  

SciTech Connect

The effect of total dose on SEU hardness is investigated as a function of temperature and power supply voltage to determine worst case hardness assurance test conditions for space environments. SRAMs from six different vendors were characterized for single-event upset (SEU) hardness at proton energies from 20 to 500 MeV and at temperatures of 25 and 80 C after total dose irradiating the SRAMs with either protons, Co-60 gamma rays, or low-energy x-rays. It is shown that total dose irradiation and the bias configuration during total dose irradiation and SEU characterization can substantially affect SEU hardness for some SRAMs. For one SRAM, the bias configuration made more than two orders of magnitude difference in SEU cross section at the highest total dose level examined. In addition, it is shown that increasing the temperature during SEU characterization can also increase the effect of total dose on SEU hardness. As a result, worst-case SEU hardness assurance test conditions are the maximum total dose and temperature of the system environment, and the minimum operating voltage of the SRAM. In contrast to previous works, our results using selective area x-ray irradiations show that the source of the effect of total dose on SEU hardness is radiation-induced leakage currents in the memory cells. The increase in SEU cross section with total dose appears to be consistent with radiation-induced currents originating in the memory cells affecting the output bias levels of bias level shift circuitry used to control the voltage levels to the memory cells and/or due to the lowering of the noise margin of individual memory cells caused by radiation-induced leakage currents.

Paillet, Philippe (CEA/DIF, Bruyeres-le-Chatel, France); Ferlet-Cavrois, V. (CEA/DIF, Bruyeres-le-Chatel, France); Flores, Richard S.; Schwank, James Ralph; Felix, James Andrew; Shaneyfelt, Marty Ray; Hash, Gerald Leon; Cole, Edward Isaac, Jr.; Blackmore, E. W. (TRIUMF, Vancouver, BC); Dodd, Paul Emerson; Baggio, J. (CEA/DIF, Bruyeres-le-Chatel, France)

2005-04-01

430

Hard Gamma Ray Emission from the Starburst Galaxy NGC 253  

NASA Technical Reports Server (NTRS)

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.

Jackson, James M.; Marscher, Alan M.

1996-01-01

431