Investigation on Surface Insulation Strength of Machinable Ceramic Material under Pulsed Voltage in Vacuum

NASA Astrophysics Data System (ADS)

Zhang, Guan-Jun; Zhao, Wen-Bin; Ma, Xin-Pei; Li, Guang-Xin; Ma, Kui; Zheng, Nan; Yan, Zhang

Ceramic material has been widely used as insulator in vacuum. Their high hardness and brittle property brings some difficulty in the application. A new kind of machinable ceramic was invented recently. The ceramic can be machined easily and accurately after being sintered, which provides the possibility of making the insulator with fine and complicated configuration. The paper studies its surface insulation performance and flashover phenomena under pulsed excitation in vacuum. The ceramic samples with different crystallization parameters are tested under the vacuum level of 10-4 Pa. The machinable ceramic behaves better surface insulation performance than comparative the Al2O3 and glass sample. The effect of crystallization level on the trap density and flashover current is also presented. After flashover shots many times, the surface microscopic patterns of different samples are observed to investigate the damage status, which can be explained by the thermal damage mechanism.

Inner surface flash-over of insulator of low-inductance high-voltage self-breakdown gas switch and its application

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Hong-bo, E-mail: walkman67@163.com; Liu, Jin-liang

2014-04-15

In this paper, the inner surface flash-over of high-voltage self-breakdown switch, which is used as a main switch of pulse modulator, is analyzed in theory by employing the method of distributed element equivalent circuit. Moreover, the field distortion of the switch is simulated by using software. The results of theoretical analysis and simulation by software show that the inner surface flash-over usually starts at the junction points among the stainless steel, insulator, and insulation gas in the switch. A switch with improved structure is designed and fabricated according to the theoretical analysis and simulation results. Several methods to avoid innermore » surface flash-over are used to improve the structure of switch. In experiment, the inductance of the switch is no more than 100 nH, the working voltage of the switch is about 600 kV, and the output voltage and current of the accelerator is about 500 kV and 50 kA, respectively. And the zero-to-peak rise time of output voltage at matched load is less than 30 ns due to the small inductance of switch. The original switch was broken-down after dozens of experiments, and the improved switch has been worked more than 200 times stably.« less

Study on the Pulsed Flashover Characteristics of Solid-Solid Interface in Electrical Devices Poured by Epoxy Resin

NASA Astrophysics Data System (ADS)

Li, Manping; Wu, Kai; Yang, Zhanping; Ding, Man; Liu, Xin; Cheng, Yonghong

2014-09-01

In electrical devices poured by epoxy resin, there are a lot of interfaces between epoxy resin and other solid dielectrics, i.e. solid-solid interfaces. Experiments were carried out to study the flashover characteristics of two typical solid-solid interfaces (epoxy-ceramic and epoxy-PMMA) under steep high-voltage impulse for different electrode systems (coaxial electrodes and finger electrodes) and different types of epoxy resin (neat epoxy resin, polyether modified epoxy resin and polyurethane modified epoxy resin). Results showed that, the flashover of solid-solid interface is similar to the breakdown of solid dielectric, and there are unrecoverable carbonated tracks after flashover. Under the same distance of electrodes, the electric stress of coaxial electrodes is lower than that of finger electrodes; and after the flashover, there are more severe breakdown and larger enhanced surface conductivity at interface for coaxial electrodes, as compared with the case of finger electrode. The dielectric properties are also discussed.

Surface charge accumulation of solid insulator under nanosecond pulse in vacuum: 3D distribution features and mechanism

NASA Astrophysics Data System (ADS)

Qi, Bo; Gao, Chunjia; Sun, Zelai; Li, Chengrong

2017-11-01

Surface charge accumulation can incur changes in electric field distribution, involved in the electron propagation process, and result in a significant decrease in the surface flashover voltage. The existing 2D surface charge measurement fails to meet the actual needs in real engineering applications that usually adopt the 45° conical frustum insulators. The present research developed a novel 3D measurement platform to capture surface charge distribution on solid insulation under nanosecond pulse in a vacuum. The results indicate that all surface charges are positive under a positive pulse and negative under a negative pulse. Surface charges tend to accumulate more near the upper electrode. Surface charge density increases significantly with the increase in pulse counts and amplitudes. Accumulation of surface charge results in a certain decrease of flashover voltage. Taking consideration of the secondary electron emission for the surface charge accumulation, four materials were obtained to demonstrate the effects on surface charge. Combining the effect incurred by secondary electron emission and the weighty action taken by surface charge accumulation on the flashover phenomena, the discharge mechanism along the insulator surface under nanosecond pulse voltage was proposed.

High voltage insulation of bushing for HTS power equipment

NASA Astrophysics Data System (ADS)

Kim, Woo-Jin; Choi, Jae-Hyeong; Kim, Sang-Hyun

2012-12-01

For the operation of high temperature superconducting (HTS) power equipments, it is necessary to develop insulating materials and high voltage (HV) insulation technology at cryogenic temperature of bushing. Liquid nitrogen (LN2) is an attractive dielectric liquid. Also, the polymer insulating materials are expected to be used as solid materials such as glass fiber reinforced plastic (GFRP), polytetra-fluoroethylene (PTFE, Teflon), Silicon (Si) rubber, aromatic polyamide (Nomex), EPDM/Silicon alloy compound (EPDM/Si). In this paper, the surface flashover characteristics of various insulating materials in LN2 are studied. These results are studied at both AC and impulse voltage under a non-uniform field. The use of GFRP and Teflon as insulation body for HTS bushing should be much desirable. Especially, GFRP is excellent material not only surface flashover characteristics but also mechanical characteristics at cryogenic temperature. The surface flashover is most serious problem for the shed design in LN2 and operation of superconducting equipments.

Low Current Surface Flashover for Initiation of Electric Propulsion Devices

NASA Astrophysics Data System (ADS)

Dary, Omar G.

There has been a recent increase in interest in miniaturization of propulsion systems for satellites. These systems are needed to propel micro- and nano-satellites, where platforms are much smaller than conventional satellites and require smaller levels of thrust. Micro-propulsion systems for these satellites are in their infancy and they must manage with smaller power systems and smaller propellant volumes. Electric propulsion systems operating on various types of electric discharges are typically used for these needs. One of the central components of such electrical micropropulsion systems are ignitor subsystems, which are required for creation the breakdown and initiation of the main discharge. Ignitors have to provide reliable ignition for entire lifetime of the micropropulsion system. Electric breakdown in vacuum usually require high voltage potentials of hundreds of kilovolts per mm to induce breakdown. The breakdown voltage can be significantly decreased (down to several kVs per mm) if dielectric surface flashover is utilized. However, classical dielectric surface flashover operates at large electric current (100s of Amperes) and associated with overheating and damage of the electrodes/dielectric assembly after several flashover events. The central idea of this work was to eliminate the damage to the flashover electrode assembly by limiting the flashover currents to low values in milliampere range (Low Current Surface Flashover -LCSF) and utilize LCSF system as an ignition source for the main discharge on the micropropulsion system. The main objective of this research was to create a robust LCSF ignition system, capable producing a large number of surface flashover triggering events without significant damage to the LCSF electrode assembly. The thesis aims to characterize the plasma plume created at LCSF, study electrodes ablation and identify conditions required for robust triggering of main discharge utilized on micro-propulsion system. Conditioning of a new LCSF assembly (flashover current was limited to <100 mA in all experiments) was measured and breakdown voltages in the range of 8kV to 12kV were observed for the fully conditioned assembly. No damage to the LCSF electrode assembly was observed after about 104 LCSF events. The LCSF assembly created sufficient amount of seed plasma in order to bridge a vacuum gap between the high-current electrodes and to reliably ignite high-current arcs (10A-12A arc were used in this work). Ignition of the high-current arc was observed at three different cases of LCSF with limiting currents 100 mA, 33 mA and 20 mA respectively. Plasma parameter measurements were conducted with variety of Langmuir probes inside the LCSF plume. Ion currents created by the LCSF were primarily expelled directly perpendicular from the insulator surface. The plasma expansion for the LCSF assembly was measured to be 2 x 106-6 x 106 cm/s. Plasma density was measured to range 10 10-1011 cm-3. The plasma density was maximal near the LCSF assembly and quickly reduced radially. Temporal decay of the plasma was observed on a time scale of about 5 micros after the LCSF event. The results of this work are significant for creation of ignitor for micropropulsion systems. LCSF system offers reliable triggering for numerous ignition pulses for entire lifetime of the micropropulsion system and reduces complexity and volume of the system by excluding moving parts and the need for an external gas tanks.

Study on the method of improving the flashover voltage of 110kV suspension porcelain insulators based on neural network genetic algorithm

NASA Astrophysics Data System (ADS)

Zhang, Ruiqi; Cai, Li; Chen, Junwu; Wang, Luo; Tan, Xuefeng

2018-04-01

This paper presents a new method to improve 110kV porcelain insulator flashover voltage by adding a metal ring on the insulator cap, which can not only effectively reduce the field strength of the steel cap, but also reduce the tangential field intensity of the umbrella group and inhibit the development of the discharge process, thus the flashover voltage can be increased. The surface strength calculation model of 110kV porcelain insulator is established by the finite element method (FEM), and the parameters of the metal ring are designed by neural network genetic algorithm (BP-GA). Then the experiments were carried out to verify the results, and the results show that the metal ring plate under the optimum parameters can greatly improve the flashover voltage.

Surface insulating properties of titanium implanted alumina ceramics by plasma immersion ion implantation

NASA Astrophysics Data System (ADS)

Zhu, Mingdong; Song, Falun; Li, Fei; Jin, Xiao; Wang, Xiaofeng; Wang, Langping

2017-09-01

The insulating property of the alumina ceramic in vacuum under high voltage is mainly limited by its surface properties. Plasma immersion ion implantation (PIII) is an effective method to modify the surface chemical and physical properties of the alumina ceramic. In order to improve the surface flashover voltage of the alumina ceramic in vacuum, titanium ions with an energy of about 20 keV were implanted into the surface of the alumina ceramic using the PIII method. The surface properties of the as-implanted samples, such as the chemical states of the titanium, morphology and surface resistivity, were characterized by X-ray photoelectron spectroscopy, scanning electron microscope and electrometer, respectively. The surface flashover voltages of the as-implanted alumina samples were measured by a vacuum surface flashover experimental system. The XPS spectra revealed that a compound of Ti, TiO2 and Al2O3 was formed in the inner surface of the alumina sample. The electrometer results showed that the surface resistivity of the implanted alumina decreased with increased implantation time. In addition, after the titanium ion implantation, the maximum hold-off voltage of alumina was increased to 38.4 kV, which was 21.5% higher than that of the unimplanted alumina ceramic.

Morphology and FT-IR analysis of anti-pollution flashover coatings with adding nano SiO2 particles

NASA Astrophysics Data System (ADS)

Guo, Kai; Du, Yishu; Wu, Yaping; Mi, Xuchun; Li, Xingeng; Chen, Suhong

2017-12-01

By adding nano SiO2 particles, an enhanced K-PRTV anti-pollution flashover coating had been prepared. Optical profile meter (GT-K), atomic force microscopy (AFM), infrared spectrometer (FT-IR) and EDS characterization were carried out on the coating surface analysis. Those results has been use to optimize the further design and platform of the enhanced K-PRTV pollution flash coating experiment. It is also to improve the plan formulation, formulation optimization and preparation of the hydrophobic modified K-PRTV which is based on anti-pollution coating experiment. More importantly, the anti-pollution flashover K-PRTV coating with super hydrophobic modified is the great significance for K-PRTV coating.

Deposition of SiC x H y O z thin film on epoxy resin by nanosecond pulsed APPJ for improving the surface insulating performance

NASA Astrophysics Data System (ADS)

Qing, XIE; Haofan, LIN; Shuai, ZHANG; Ruixue, WANG; Fei, KONG; Tao, SHAO

2018-02-01

Non-thermal plasma surface modification for epoxy resin (EP) to improve the insulation properties has wide application prospects in gas insulated switchgear and gas insulated transmission line. In this paper, a pulsed Ar dual dielectrics atmospheric-pressure plasma jet (APPJ) was used for SiC x H y O z thin film deposition on EP samples. The film deposition was optimized by varying the treatment time while other parameters were kept at constants (treatment distance: 10 mm, precursor flow rate: 0.6 l min-1, maximum instantaneous power: 3.08 kW and single pulse energy: 0.18 mJ). It was found that the maximum value of flashover voltages for negative and positive voltage were improved by 18% and 13% when the deposition time was 3 min, respectively. The flashover voltage reduced as treatment time increased. Moreover, all the surface conductivity, surface charge dissipation rate and surface trap level distribution reached an optimal value when thin film deposition time was 3 min. Other measurements, such as atomic force microscopy and scanning electron microscope for EP surface morphology, Fourier transform infrared spectroscopy and x-ray photoelectron spectroscopy for EP surface compositions, optical emission spectra for APPJ deposition process were carried out to better understand the deposition processes and mechanisms. The results indicated that the original organic groups (C-H, C-C, C=O, C=C) were gradually replaced by the Si containing inorganic groups (Si-O-Si and Si-OH). The reduction of C=O in ester group and C=C in p-substituted benzene of the EP samples might be responsible for shallowing the trap level and then enhancing the flashover voltage. However, when the plasma treatment time was longer than 3 min, the significant increase of the surface roughness might increase the trap level depth and then deteriorate the flashover performance.

Temporal response of a surface flashover on a velvet cathode in a relativistic diode

DOE PAGES

Coleman, J. E.; Moir, D. C.; Crawford, M. T.; ...

2015-03-11

Surface flashover of a carbon fiber velvet cathode generates a discharge from which electrons are relativistically accelerated to γ ranging from 4.9 to 8.8 through a 17.8 cm diode. This discharge is assumed to be a hydrocarbon mixture. Our objective is to quantify the dynamics over the ~100 ns pulse of the plasma discharge generated on the surface of the velvet cathode and across the anode-cathode (A-K) gap. We present a qualitative comparison of calculated and measured results, which includes time resolved measurements with a photomultiplier tube and charge-coupled device images. Additionally, initial visible spectroscopy measurements will also be presentedmore » confirming the ion species are dominated by hydrogen.« less

Temporal response of a surface flashover on a velvet cathode in a relativistic diode

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coleman, J. E.; Moir, D. C.; Crawford, M. T.

2015-03-15

Surface flashover of a carbon fiber velvet cathode generates a discharge from which electrons are relativistically accelerated to γ ranging from 4.9 to 8.8 through a 17.8 cm diode. This discharge is assumed to be a hydrocarbon mixture. The principal objective of these experiments is to quantify the dynamics over the ∼100 ns pulse of the plasma discharge generated on the surface of the velvet cathode and across the anode-cathode (A-K) gap. A qualitative comparison of calculated and measured results is presented, which includes time resolved measurements with a photomultiplier tube and charge-coupled device images. In addition, initial visible spectroscopy measurements willmore » also be presented confirming the ion species are dominated by hydrogen.« less

Surface discharge related properties of fiberglass reinforced plastic insulator for use in neutral beam injector of JT-60U.

PubMed

Yamano, Y; Takahashi, M; Kobayashi, S; Hanada, M; Ikeda, Y

2008-02-01

Neutral beam injection (NBI) used for JT-60U is required to generate negative ions of 500 keV energies. To produce such high-energy ions, three-stage electrostatic accelerators consisting of three insulator rings made of fiberglass reinforced plastic (FRP) are applied. The surface discharges along FRP insulators are one of the most serious problems in the development of NBI. To increase the hold-off voltage against surface flashover events, it is necessary to investigate the FRP insulator properties related to surface discharges in vacuum. This paper describes surface flashover characteristics for FRP and alumina samples under vacuum condition. The results show that the fold-off voltages for FRP samples are inferior to those of alumina ceramics. In addition, measurement results of surface resistivity and volume resistivity under vacuum and atmospheric conditions, secondary electron emission characteristics, and cathodoluminescence under some keV electron beam irradiation are also reported. These are important parameters to analyze surface discharge of insulators in vacuum.

Surface discharge related properties of fiberglass reinforced plastic insulator for use in neutral beam injector of JT-60Ua)

NASA Astrophysics Data System (ADS)

Yamano, Y.; Takahashi, M.; Kobayashi, S.; Hanada, M.; Ikeda, Y.

2008-02-01

Neutral beam injection (NBI) used for JT-60U is required to generate negative ions of 500keV energies. To produce such high-energy ions, three-stage electrostatic accelerators consisting of three insulator rings made of fiberglass reinforced plastic (FRP) are applied. The surface discharges along FRP insulators are one of the most serious problems in the development of NBI. To increase the hold-off voltage against surface flashover events, it is necessary to investigate the FRP insulator properties related to surface discharges in vacuum. This paper describes surface flashover characteristics for FRP and alumina samples under vacuum condition. The results show that the fold-off voltages for FRP samples are inferior to those of alumina ceramics. In addition, measurement results of surface resistivity and volume resistivity under vacuum and atmospheric conditions, secondary electron emission characteristics, and cathodoluminescence under some keV electron beam irradiation are also reported. These are important parameters to analyze surface discharge of insulators in vacuum.

Surface Electric Strength of Thermoplastic Materials in Vacuum

DTIC Science & Technology

1981-11-27

For all the 1 lengths of investigated samples the flashover voltage showed the tendency of going down as the pressure increased from 133.322xi0" 6 Pa to...0,4 =326%10-8 133.32?*0 133= 322 -10V Figure 5.1. Flashover voltage as a function of pressure for samplesfrom polymethylmethacrylate. Direct...course of switching surge 400/2000 ýis L -76 AV L 1t0 01 1󈧶 01’O Tr W33.322.106 033.32210-" I33.322-10Ŗ 133.)2210- W3. 322 . 10-" Pa Figure 5.2

Creeping flashover characteristics improvement of nanofluid/pressboard system with TiO2 nanoparticles

NASA Astrophysics Data System (ADS)

Huang, Meng; Wang, Lei; Ge, Yang; Lv, Yu-zhen; Qi, Bo; Li, Cheng-rong

2018-03-01

Creeping flashover easily occurs at the interface between oil and pressboard in transformer and thus results in outage of power transmission system. Investigations have shown that creeping flashover characteristics at oil/pressboard interface can be improved by the addition of TiO2 nanoparticles, but the mechanism is still not thoroughly known. In this work, creeping flashover performance at nanofluid/pressboard interface modified by different sizes of nanoparticles were studied and the mechanism was presented as well. Nanofluids with the same concentration but with different sizes of TiO2 nanoparticles were prepared, and pressboards impregnated with them were prepared as well. After that, their creeping flashover characteristics were measured and compared. Nanoparticle's size affected the creeping flashover performance along oil/pressboard greatly under both AC and lightning impulse voltages. The highest creeping flashover voltage can be enhanced by as high as 12.2% and 32.0% respectively. The underlying electric field distribution and charge transportation behaviors were analyzed to demonstrate the influence of nanoparticle's size. By the addition of nanoparticles with a smaller size, the dielectric constant of nanofluid was increased closer to that of the pressboard, thus they were matched better. Moreover, charge was easier to dissipate from the oil/pressboard interface and electric field distortion at the interface was consequently reduced. Therefore, the electric field was more like a uniform field and the forward development of flashover was more difficult, leading to a better performance of creeping flashover of oil-impregnated pressboard.

Effects of nano-SiO{sub 2} particles on surface tracking characteristics of silicone rubber composites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Yong, E-mail: tjuliuyong@tju.edu.cn; Li, Zhonglei; Du, Boxue

Compared with neat silicone rubber composites (SiRCs), SiRCs filled with nano-sized SiO{sub 2} particles at weight ratios from 0.1 to 1.0 wt. % exhibit a higher surface flashover voltage and a greater resistance to surface tracking. Scanning electron microscopy images of tracking morphologies indicate that the SiO{sub 2} particles are situated in close proximity to the polymeric chains and act as bridges to stabilize the chains and maintain the structure of the composite. Higher concentrations of nano-sized SiO{sub 2} particles, however, (above 0.3 wt. %) produce defects in the molecular network which lead to reductions in both the surface flashover voltage and the resistancemore » to surface tracking, although these reduced values are still superior to those of neat SiRCs. Therefore, SiRCs filled with nano-sized SiO{sub 2} particles, especially at an optimal weight ratio (0.1 to 0.3 wt. %), may have significant potential applications as outdoor insulators for power systems.« less

Modeling of surface flashover on spacecraft

NASA Technical Reports Server (NTRS)

Kushner, Mark J.

1991-01-01

A model for predicting the onset of surface flashover discharges (SFDs) in the context of high voltage pulse power modulators was developed and used to investigate mechanisms leading to the onset of SFDs. We demonstrated that it is possible to analyze surface discharges in a manner similar to gas phase discharges using transport coefficients such as the first Townsend coefficient. Our parameterization of various methods to prevent, or at least delay, the onset of SFDs was not particularly successful in that many of the strategies that we investigated do not yield significantly improved performance. The only safe strategy to reduce the occurrence of SFDs is to prevent the dielectric from being charged in the first place. This leads one to consider passive or active schemes which employ the low pressure of attaching gases which flood the surface prior or coincident to pulsing the high voltage apparatus. Our calculations indicate that only small amounts gas (10s Torr effective pressure at substrate) would be sufficient for many of the anticipated applications. If the surface is flooded only when high voltage is applied across the dielectric, the gas consumption would be nominal.

Skin Effect Simulation for Area 11 Dense Plasma Focus Hot Plate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meehan, B. Timothy

Two arc flashover events occurred at the DPF Area 11 facility. These flashover events happened in the same location on the bank current delivery plates. The damage from one of these events can be seen on the left-hand side of Figure 1. Since the flashovers occurred in the same area of the bank, and the reliability of the bank is important for future DPF experiments, a failure analysis effort was initiated. Part of this failure analysis effort was an effort to understand the physical reasons behind why the flashover happened, and why it happened in the same place twice. Thismore » paper summarizes an effort to simulate the current flow in the bank in order to understand the reasons for the flashover.« less

Evaluation of Kapton pyrolysis, arc tracking, and flashover on SiO(x)-coated polyimide insulated samples of flat flexible current carriers for Space Station Freedom

NASA Technical Reports Server (NTRS)

Stueber, Thomas J.; Mundson, Chris

1993-01-01

Kapton polyimide wiring insulation was found to be vulnerable to pyrolization, arc tracking, and flashover when momentary short-circuit arcs have occurred on aircraft power systems. Short-circuit arcs between wire pairs can pyrolize the polyimide resulting in a conductive char between conductors that may sustain the arc (arc tracking). Furthermore, the arc tracking may spread (flashover) to other wire pairs within a wire bundle. Polyimide Kapton will also be used as the insulating material for the flexible current carrier (FCC) of Space Station Freedom (SSF). The FCC, with conductors in a planar type geometric layout as opposed to bundles, is known to sustain arc tracking at proposed SSF power levels. Tests were conducted in a vacuum bell jar that was designed to conduct polyimide pyrolysis, arc tracking, and flashover studies on samples of SSF's FCC. Test results will be reported concerning the minimal power level needed to sustain arc tracking and the FCC susceptibility to flashover. Results of the FCC arc tracking tests indicate that only 22 volt amps were necessary to sustain arc tracking (proposed SSF power level is 400 watts). FCC flashover studies indicate that the flashover event is highly unlikely.

Voltage Sag due to Pollution Induced Flashover Across Ceramic Insulator Strings

NASA Astrophysics Data System (ADS)

Reddy B, Subba; Goswami, Arup Kumar

2017-11-01

Voltage sag or voltage dips are significant to industrial reliability. There is a necessity to characterize the feeder level power quality (PQ) and the PQ performance among various utility companies. Contamination/pollution induced flashover is the ultimate consequence of the creeping discharges across the insulator strings which induce voltage sag. These have a severe threat on the safe and reliable operation of power systems. In the present work an attempt has been made to experimentally investigate the occurrence of voltage sag/dips during pollution induced flashovers. Results show significant dip/sag in the voltage magnitude during the flashover process.

External insulation of electrified railway and energy saving analysis

NASA Astrophysics Data System (ADS)

Dun, Xiaohong

2018-04-01

Through the analysis of the formation process of insulator surface fouling and the cause of fouling of the insulator, the electrified railway was explored to utilize the coating material on the surface of the insulator to achieve the effect of flashover prevention. At the same time the purpose of energy conservation can be achieved.

Mechanism and influencing factors on critical pulse width of oil-immersed polymer insulators under short pulses

NASA Astrophysics Data System (ADS)

Zhao, Liang; Su, Jian Cang; Li, Rui; Zeng, Bo; Cheng, Jie; Zheng, Lei; Yu, Bin Xiong; Wu, Xiao Long; Zhang, Xi Bo; Pan, Ya Feng

2015-04-01

The critical pulse width (τc) is a pulse width at which the surface flashover threshold (Ef) is equal to the bulk breakdown threshold (EBD) for liquid-polymer composite insulation systems, which is discovered by Zhao et al. [Annual Report Conference on Electrical Insulation and Dielectric Phenomena (IEEE Dielectrics and Electrical Insulation Society, Shenzhen, China, 2013), Vol. 2, pp. 854-857]. In this paper, the mechanism of τc is interpreted in perspective of the threshold and the time delay (td) of surface flashover and bulk breakdown, respectively. It is found that two changes appear as the pulse width decreases which are responsible for the existence of τc: (1) EBD is lower than Ef; (2) td of bulk breakdown is shorter than td of surface flashover. In addition, factors which have influences on τc are investigated, such as the dielectric type, the insulation length, the dielectric thickness, the dielectrics configuration, the pulse number, and the liquid purity. These influences of factors are generalized as three types if τc is expected to increase: (1) factors causing EBD to decrease, such as increasing the pulse number or employing a dielectric of lower EBD; (2) factors causing Ef to increase, such as complicating the insulator's configuration or increasing the liquid purity; (3) factors causing EBD and Ef to increase together, but Ef increases faster than EBD, such as decreasing the dielectric thickness or the insulation length. With the data in references, all the three cases are verified experimentally. In the end, a general method based on τc for solid insulation design is presented and the significance of τc on solid insulation design and on solid demolition are discussed.

On the surface trapping parameters of polytetrafluoroethylene block

NASA Astrophysics Data System (ADS)

Zhang, Guan-Jun; Yang, Kai; Zhao, Wen-Bin; Yan, Zhang

2006-12-01

Surface flashover phenomena under high electric field are closely related to the surface characteristics of a solid insulating material between energized electrodes. Based on measuring the surface potential decaying curve of polytetrafluoroethylene (PTFE) block charged by a needle-plane corona discharge, its surface trapping parameters are calculated with the isothermal current theory, and the correlative curve between the surface trap density and its energy level is obtained. The maximum density of electron traps and hole traps in the surface layer of PTFE presents a similar value of ∼2.7 × 1017 eV-1 m-3, and the energy level of its electron and hole traps is of about 0.85-1.0 eV and 0.80-0.90 eV, respectively. Via the X-ray photoelectron spectroscopy (XPS) technique, the F, C, K and O elements are detected on the surface of PTFE samples, and F shows a remarkable atom proportion of ∼73.3%, quite different from the intrinsic distribution corresponding to its chemical formula. The electron traps are attributed to quantities of F atoms existing on the surface of PTFE due to its molecular chain with C atoms surrounded by F atoms spirally. It is considered that the distortions of chemical and electronic structure on solid surface are responsible for the flashover phenomena occurring at a low applied voltage.

Spatiotemporal temperature and density characterization of high-power atmospheric flashover discharges over inert poly(methyl methacrylate) and energetic pentaerythritol tetranitrate dielectric surfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tang, V.; Grant, C. D.; McCarrick, J. F.

2012-03-01

A flashover arc source that delivered up to 200 mJ on the 100s-of-ns time-scale to the arc and a user-selected dielectric surface was characterized for studying high-explosive kinetics under plasma conditions. The flashover was driven over thin pentaerythritol tetranitrate (PETN) and poly(methyl methacrylate) (PMMA) dielectric films and the resultant plasma was characterized in detail. Time- and space-resolved temperatures and electron densities of the plasma were obtained using atomic emission spectroscopy. The hydrodynamics of the plasma was captured through fast, visible imaging. Fourier transform infrared spectroscopy (FTIR) was used to characterize the films pre- and post-shot for any chemical alterations. Time-resolvedmore » infrared spectroscopy (TRIR) provided PETN depletion data during the plasma discharge. For both types of films, temperatures of 1.6-1.7 eV and electron densities of {approx}7-8 x 10{sup 17}/cm{sup 3}{approx}570 ns after the start of the discharge were observed with temperatures of 0.6-0.7 eV persisting out to 15 {mu}s. At 1.2 {mu}s, spatial characterization showed flat temperature and density profiles of 1.1-1.3 eV and 2-2.8 x 10{sup 17}/cm{sup 3} for PETN and PMMA films, respectively. Images of the plasma showed an expanding hot kernel starting from radii of {approx}0.2 mm at {approx}50 ns and reaching {approx}1.1 mm at {approx}600 ns. The thin films ablated or reacted several hundred nm of material in response to the discharge. First TRIR data showing the in situ reaction or depletion of PETN in response to the flashover arc were successfully obtained, and a 2-{mu}s, 1/e decay constant was measured. Preliminary 1 D simulations compared reasonably well with the experimentally determined plasma radii and temperatures. These results complete the first steps to resolving arc-driven PETN reaction pathways and their associated kinetic rates using in situ spectroscopy techniques.« less

NASCAP simulation of laboratory charging tests using multiple electron guns

NASA Technical Reports Server (NTRS)

Mandell, M. J.; Katz, I.; Parks, D. E.

1981-01-01

NASCAP calculations have been performed simulating exposure of a spacecraft-like model to multiple electron guns. The results agree well with experiment. It is found that magnetic field effects are fairly small, but substantial differential charging can result from electron gun placement. Conditions for surface flashover are readily achieved.

Mechanism and influencing factors on critical pulse width of oil-immersed polymer insulators under short pulses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Liang, E-mail: zhaoliang@ninit.ac.cn; Li, Rui; Zheng, Lei

2015-04-15

The critical pulse width (τ{sub c}) is a pulse width at which the surface flashover threshold (E{sub f}) is equal to the bulk breakdown threshold (E{sub BD}) for liquid-polymer composite insulation systems, which is discovered by Zhao et al. [Annual Report Conference on Electrical Insulation and Dielectric Phenomena (IEEE Dielectrics and Electrical Insulation Society, Shenzhen, China, 2013), Vol. 2, pp. 854–857]. In this paper, the mechanism of τ{sub c} is interpreted in perspective of the threshold and the time delay (t{sub d}) of surface flashover and bulk breakdown, respectively. It is found that two changes appear as the pulse widthmore » decreases which are responsible for the existence of τ{sub c}: (1) E{sub BD} is lower than E{sub f}; (2) t{sub d} of bulk breakdown is shorter than t{sub d} of surface flashover. In addition, factors which have influences on τ{sub c} are investigated, such as the dielectric type, the insulation length, the dielectric thickness, the dielectrics configuration, the pulse number, and the liquid purity. These influences of factors are generalized as three types if τ{sub c} is expected to increase: (1) factors causing E{sub BD} to decrease, such as increasing the pulse number or employing a dielectric of lower E{sub BD}; (2) factors causing E{sub f} to increase, such as complicating the insulator's configuration or increasing the liquid purity; (3) factors causing E{sub BD} and E{sub f} to increase together, but E{sub f} increases faster than E{sub BD}, such as decreasing the dielectric thickness or the insulation length. With the data in references, all the three cases are verified experimentally. In the end, a general method based on τ{sub c} for solid insulation design is presented and the significance of τ{sub c} on solid insulation design and on solid demolition are discussed.« less

Effects of the injected plasma on the breakdown process of the trigatron gas switch under low working coefficient

NASA Astrophysics Data System (ADS)

Chen, Li; Yang, Lanjun; Qiu, Aici; Huang, Dong; Liu, Shuai

2018-01-01

Based on the surface flashover discharge, the injected plasma was generated, and the effects on the breakdown process of the trigatron gas switch were studied in this paper. The breakdown model caused by the injected plasma under the low working coefficient (<0.7) was established. The captured framing images showed that the injected plasma distorted the electrical field of the gap between the frontier of the injected plasma and the opposite electrode, making it easier to achieve the breakdown critical criterion. The calculation results indicated that the breakdown delay time was mainly decided by the development of the injected plasma, as without considering the effects of the photo-ionization and the invisible expansion process, the breakdown delay time of the calculation results was 20% higher than the experimental results. The morphology of the injected plasma generated by polyethylene surface flashover was more stable and regular than ceramic, leading to a 30% lower breakdown delay time when the working coefficient is larger than 0.2, and the difference increased sharply when the working coefficient is lower than 0.2. This was significant for improving the trigger performance of the trigatron gas switch under low working coefficient.

Influence of sub-surface damage evolution on low-energy-plasma-driven deuterium permeation through tungsten

NASA Astrophysics Data System (ADS)

Kapser, Stefan; Balden, Martin; Fiorini da Silva, Tiago; Elgeti, Stefan; Manhard, Armin; Schmid, Klaus; Schwarz-Selinger, Thomas; von Toussaint, Udo

2018-05-01

Low-energy-plasma-driven deuterium permeation through tungsten at 300 K and 450 K has been investigated. Microstructural analysis by scanning electron microscopy, assisted by focused ion beam, revealed sub-surface damage evolution only at 300 K. This damage evolution was correlated with a significant evolution of the deuterium amount retained below the plasma-exposed surface. Although both of these phenomena were observed for 300 K exposure temperature only, the deuterium permeation flux at both exposure temperatures was indistinguishable within the experimental uncertainty. The permeation flux was used to estimate the maximum ratio of solute-deuterium to tungsten atoms during deuterium-plasma exposure at both temperatures and thus in the presence and absence of damage evolution. Diffusion-trapping simulations revealed the proximity of damage evolution to the implantation surface as the reason for an only insignificant decrease of the permeation flux.

Creation of deuterium protective layer below the tungsten surface

NASA Astrophysics Data System (ADS)

Krstic, Predrag; Kaganovich, Igor; Startsev, Edward

2014-10-01

By cumulative irradiation of both pre-damaged and virgin surfaces of monocrystal tungsten by deuterium atoms of impact energy of few tens of eV, we simulate by classical molecular dynamics the creation of a deuterium protective layer. The depth and width of the layer depend on the deuterium impact energy and the diffusion rate of deuterium in tungsten, the latter being influenced by the tungsten temperature and damage. Found simulation results are in concert with the experimental results, found recently in DIFFER. Support of the PPPL LDRD project acknowledged.

Studies on the determination of surface deuterium in AISI 1062, 4037, and 4140 steels by secondary ion mass spectrometry

NASA Astrophysics Data System (ADS)

Sastri, V. S.; Donepudi, V. S.; McIntyre, N. S.; Johnston, D.; Revie, R. W.

1988-12-01

The concentration of deuterium at the surface of cathodically charged high strength steels AISI 1062, 4037, and 4140 has been determined by secondary ion mass spectrometry (SIMS). The beneficial effects of pickling in NAP (a mixture of nitric, acetic, and phosphoric acids) to remove surfacebound deuterium have been observed.

Room/corner tests of wall linings with 100/300 kW burner

Treesearch

M. A. Dietenberger; O. Grexa; R. H. White; M. S. Sweet; M. Janssens

1995-01-01

Six room/comer tests of common wall linings were conducted with gypsum-lined ceiling exposed to propane burning at 100 kW for 10 min followed by 300 kW for 10 min. This test protocol is an option provided by ISO 9705. The flashover event occurred at 1,000 kW rate of heat release within several seconds of observing flames out the doorway. The time to flashover of the...

Protection of Electrical Systems from EM Hazards - Design Guide.

DTIC Science & Technology

1981-09-01

cm) Surface flashover Voltage (KV/cm) This criterion should be met for lighting voltage stresses of either polarity applied at up to 1000 KV/v sec rate...suppressor devices can be predicted. The part failure rate models in the handbook include the effects of part electrical stress , thermal stress , operating... stress . This test series contained over one million device hours of operation at temperatures uF to 145°C. The average duration of testing ranges from

Characterization of the Electrostatic Environment of Launchers

NASA Astrophysics Data System (ADS)

Soyah, Jamila; Mantion, Pascal; Herlem, Yannick

2016-05-01

The purpose of this study was to update knowledge in characterization of the electrostatic environment of launchers in order to be able to propose reductions of design constraints.The first part of this study showed that flashover discharges are the most energetic discharges likely to occur on a launcher. They are mostly due to accumulations of charges by triboelectricity on the external surface of the launcher while flying through clouds containing a lot of small solid particles.Actually flashover discharges are mitigated by limiting the surface's resistance of dielectric materials such as thermal protection set on the external skin of the launcher, thanks to antistatic paints that avoid significant accumulations of charges.But this specified limitation leads to a lot of non- conformances during production phases and, as a result, this leads to additional costs and delays in launches campaigns. That is why on-ground tests have been defined in order to assess the accessibility of a relaxation of those specifications, which would reduce non-conformances.On-ground tests have been carried out, in the second part, on samples of thermal protections covered with antistatic paints with different degraded values of surface resistance. These tests aimed at checking in which conditions a surface discharge can occur in order to deduce a relationship between characteristics of the samples (surface resistance, half-discharge time) and the occurrence of a surface discharge, at ambient pressure and at low pressure.In the third part, in-flight experiments have been defined in order to confirm some hypotheses considered in the study and to assess some parameters in a more accurate way like the incoming charges density per surface unit or the voltage between stages when they get separated, in order to assess more accurately whether the unwinding equalization wire dedicated to maintain the electrostatic balance between stages is necessary or not.

Studies of lithiumization and boronization of ATJ graphite PFCs for NSTX-U

NASA Astrophysics Data System (ADS)

Dominguez, Javier; Bedoya, Felipe; Krstic, Predrag; Allain, Jean Paul; Neff, Anton; Luitjohan, Kara

2016-10-01

We examine and compare the effects of boron and lithium conditioning on ATJ graphite surfaces bombarded by low-energy deuterium atoms on deuterium retention and chemical sputtering. We use atomistic simulations and compare them with experimental in-situ ex-tempore studies with X-ray photoelectron spectroscopy (XPS), to understand the effects of deuterium exposure on the chemistry in lithiated, boronized and oxidized amorphous carbon surfaces. Our results are validated qualitatively by comparison with experiments and with classical-quantum molecular dynamic simulations. We explain the important role of oxygen in D retention for lithiated surfaces and the suppression of the oxygen role by boron in boronized surfaces. The calculated increase of the oxygen role in deuterium uptake after D accumulation in a B-C-O surface configuration is discussed. The sputtering yield per low-energy D impact is significantly smaller in boronized surfaces than in lithiated surfaces. This work was supported by the USDOE Grants DE-SC0013752 (PSK), DE-SC0010717 (JPA and FB) and DE-SC0010719 (AN) and by National council for Science and Technology of Mexico (CONACyT) through postdoctoral fellowship # 267898 (JD).

The temperature and ion energy dependence of deuterium retention in lithium films

NASA Astrophysics Data System (ADS)

Buzi, Luxherta; Koel, Bruce E.; Skinner, Charles H.

2016-10-01

Lithium conditioning of plasma facing components in magnetic fusion devices has improved plasma performance and lowered hydrogen recycling. For applications of lithium in future high heat flux and long pulse duration machines it is important to understand and parameterize deuterium retention in lithium. This work presents surface science studies of deuterium retention in lithium films as a function of surface temperature, incident deuterium ion energy and flux. Initial experiments are performed on thin (3-30 ML) lithium films deposited on a single crystal molybdenum substrate to avoid effects due to grain boundaries, intrinsic defects and impurities. A monoenergetic and mass-filtered deuterium ion beam was generated in a differentially pumped Colutron ion gun. Auger electron spectroscopy and X-ray photoelectron spectroscopy were used to identify the elemental composition and temperature programmed desorption was used to measure the deuterium retention under the different conditions. Support was provided through DOE Contract Number DE-AC02-09CH11466.

Surface degradation of polymer insulators under accelerated climatic aging in weather-ometer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, G.; McGrath, P.B.; Burns, C.W.

1996-12-31

Climatic aging experiments were conducted on two types of outdoor polymer insulators by using a programmable weather-ometer. The housing materials for the insulators were silicone rubber (SR) and ethylene propylene diene monomer (EPDM). The accelerated aging stresses were comprised of ultraviolet radiation, elevated temperature, temperature cycling, thermal shock and high humidity. Their effects on the insulator surface conditions and electrical performance wee examined through visual inspection and SEM studies, contact angle measurements, thermogravimetric analysis (TGA), energy dispersive spectroscopy (EDS) analysis, and 50% impulse flashover voltage tests. The results showed a significant damage on the insulator surface caused by some ofmore » the imposed aging stresses. The EDS analysis suggested a photooxidation process that happened on the insulator surface during the aging period.« less

Deuterium Retention and Physical Sputtering of Low Activation Ferritic Steel

NASA Astrophysics Data System (ADS)

T, Hino; K, Yamaguchi; Y, Yamauchi; Y, Hirohata; K, Tsuzuki; Y, Kusama

2005-04-01

Low activation materials have to be developed toward fusion demonstration reactors. Ferritic steel, vanadium alloy and SiC/SiC composite are candidate materials of the first wall, vacuum vessel and blanket components, respectively. Although changes of mechanical-thermal properties owing to neutron irradiation have been investigated so far, there is little data for the plasma material interactions, such as fuel hydrogen retention and erosion. In the present study, deuterium retention and physical sputtering of low activation ferritic steel, F82H, were investigated by using deuterium ion irradiation apparatus. After a ferritic steel sample was irradiated by 1.7 keV D+ ions, the weight loss was measured to obtain the physical sputtering yield. The sputtering yield was 0.04, comparable to that of stainless steel. In order to obtain the retained amount of deuterium, technique of thermal desorption spectroscopy (TDS) was employed to the irradiated sample. The retained deuterium desorbed at temperature ranging from 450 K to 700 K, in the forms of DHO, D2, D2O and hydrocarbons. Hence, the deuterium retained can be reduced by baking with a relatively low temperature. The fluence dependence of retained amount of deuterium was measured by changing the ion fluence. In the ferritic steel without mechanical polish, the retained amount was large even when the fluence was low. In such a case, a large amount of deuterium was trapped in the surface oxide layer containing O and C. When the fluence was large, the thickness of surface oxide layer was reduced by the ion sputtering, and then the retained amount in the oxide layer decreased. In the case of a high fluence, the retained amount of deuterium became comparable to that of ferritic steel with mechanical polish or SS 316L, and one order of magnitude smaller than that of graphite. When the ferritic steel is used, it is required to remove the surface oxide layer for reduction of fuel hydrogen retention. Ferritic steel sample was exposed to the environment of JFT-2M tokamak in JAERI and after that the deuterium retention was examined. The result was roughly the same as the case of deuterium ion irradiation experiment.

Deuterium retention and surface modification of tungsten macrobrush samples exposed in FTU Tokamak

NASA Astrophysics Data System (ADS)

Maddaluno, G.; Giacomi, G.; Rufoloni, A.; Verdini, L.

2007-06-01

The effect of discrete structures such as macrobrush or castellated surfaces on power handling and deuterium retention of plasma facing components is to be assessed since such geometrical configurations are needed for increasing the lifetime of the armour to heat-sink joint. Four small macrobrush W and W + 1%La2O3 samples have been exposed in the Frascati Tokamak Upgrade (FTU) scrape-off layer up to the last closed flux surface by means of the Sample Introduction System. FTU is an all metal machine with no carbon source inside vacuum vessel; it exhibits ITER relevant energy and particle fluxes on the plasma facing components. Here, results on morphological surface changes (SEM), chemical composition (EDX) and deuterium retention (TDS) are reported.

Overview of HIT-SI Results and Plans

NASA Astrophysics Data System (ADS)

Ennis, D. A.; Akcay, C.; Hansen, C. J.; Hicks, N. K.; Hossack, A. C.; Jarboe, T. R.; Marklin, G. J.; Nelson, B. A.; Victor, B. S.

2011-10-01

Experiments in the Helicity Injected Torus-Steady Inductive (HIT-SI) device have achieved record spheromak current amplification during operations in deuterium plasmas. HIT-SI investigates steady inductive helicity injection with the aim of forming and sustaining a high-beta equilibrium in a spheromak geometry using two semi-toroidal injectors. Recent operations in deuterium plasmas have produced toroidal plasma currents greater than 50 kA, with current amplifications (Itor / Iinj) > 3 , and poloidal flux amplifications (ψpol /ψinj) > 10 . High performance deuterium discharges are achieved by initially conditioning the plasma-facing alumina surface of the HIT-SI confinement volume with helium plasmas. During subsequent deuterium operation the alumina surface strongly pumps deuterium, thereby limiting the density in the confinement volume. Additional measurements during high current deuterium discharges demonstrate reduced current and electron density fluctuations, impurity O III ion temperatures up to 50 eV and a toroidal current persistence for 0.6 ms after the injectors are shut off. Progress and plans for the HIT-SI3 configuration, with three injectors mounted on the same side of the confinement volume, will also be presented. Work supported by USDoE and ARRA.

Structural Changes in the Vanadium Sample Surface Induced by Pulsed High-Temperature Deuterium Plasma and Deuterium Ion Fluxes

NASA Astrophysics Data System (ADS)

Borovitskaya, I. V.; Pimenov, V. N.; Gribkov, V. A.; Padukh, M.; Bondarenko, G. G.; Gaidar, A. I.; Paramonova, V. V.; Morozov, E. V.

2017-11-01

The structural changes in the vanadium sample surface are studied as functions of the conditions of irradiation by pulsed high-temperature deuterium plasma and deuterium ion fluxes in the Plasma Focus installation. It is found that processes of partial evaporation, melting, and crystallization of the surface layer of vanadium samples take place in the plasma flux power density range q = 108-1010 W/cm2 and the ion flux density range q = 1010-1012 W/cm2. The surface relief is wavelike. There are microcracks, gas-filled bubbles (blisters), and traces of fracture on the surface. The blisters are failed in the solid state. The character of blister fracture is similar to that observed during usual ion irradiation in accelerators. The samples irradiated at relatively low power density ( q = 107-108 W/cm2) demonstrate the ejection of microparticles (surface fragments) on the side facing plasma. This process is assumed to be due to the fact that the unloading wave formed in the sample-target volume reaches its irradiated surface. Under certain irradiation conditions (sample-anode distance, the number of plasma pulses), a block microstructure with block sizes of several tens of microns forms on the sample surfaces. This structure is likely to form via directional crack propagation upon cooling of a thin melted surface layer.

Implanted Deuterium Retention and Release in Carbon-Coated Beryllium

NASA Astrophysics Data System (ADS)

Anderl, R. A.; Longhurst, G. R.; Pawelko, R. J.; Oates, M. A.

1997-06-01

Deuterium implantation experiments have been conducted on samples of clean and carbon-coated beryllium. These studies entailed preparation and characterization of beryllium samples coated with carbon thicknesses of 100, 500, and 1000 Å. Heat treatment of a beryllium sample coated with carbon to a thickness of approximately 100 Å revealed that exposure to a temperature of 400°C under high vacuum conditions was sufficient to cause substantial diffusion of beryllium through the carbon layer, resulting in more beryllium than carbon at the surface. Comparable concentrations of carbon and beryllium were observed in the bulk of the coating layer. Higher than expected oxygen levels were observed throughout the coating layer as well. Samples were exposed to deuterium implantation followed by thermal desorption without exposure to air. Differences were observed in deuterium retention and postimplantation release behavior in the carbon-coated samples as compared with bare samples. For comparable implantation conditions (sample temperature of 400°C and an incident deuterium flux of approximately 6 × 1019 D/m2-s), the quantity of deuterium retained in the bare sample was less than that retained in the carbon-coated samples. Further, the release of the deuterium took place at lower temperatures for the bare beryllium surfaces than for carbon-coated beryllium samples.

Evidence for Nuclear Tensor Polarization of Deuterium Molecules in Storage Cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

van den Brand, J.; Bulten, H.; Zhou, Z.

1997-02-01

Deuterium molecules were obtained by recombination, on a copper surface, of deuterium atoms prepared in specific hyperfine states. The molecules were stored for about 5ms in an open-ended cylindrical cell, placed in a 23mT magnetic field, and their tensor polarization was measured by elastic scattering of 704MeV electrons. The results of the measurements are consistent with the deuterium molecules retaining the tensor polarization of the initial atoms. {copyright} {ital 1997} {ital The American Physical Society}

DYNAMIC DEUTERIUM ENRICHMENT IN COMETARY WATER VIA ELEY–RIDEAL REACTIONS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yao, Yunxi; Giapis, Konstantinos P., E-mail: giapis@cheme.caltech.edu

2017-01-20

The deuterium-to-hydrogen ratio (D/H) in water found in the coma of Jupiter family comet (JFC) 67P/Churyumov–Gerasimenko was reported to be (5.3 ± 0.7) × 10{sup −4}, the highest among comets and three times the value for other JFCs with an ocean-like ratio. This discrepancy suggests the diverse origins of JFCs and clouds the issue of the origin of Earth’s oceanic water. Here we demonstrate that Eley–Rideal reactions between accelerated water ions and deuterated cometary surface analogs can lead to instantaneous deuterium enrichment in water scattered from the surface. The reaction proceeds with H{sub 2}O{sup +} abstracting adsorbed D atoms, formingmore » an excited H{sub 2}DO* state, which dissociates subsequently to produce energetic HDO. Hydronium ions are also produced readily by the abstraction of H atoms, consistent with H{sub 3}O{sup +} detection and abundance in various comets. Experiments with water isotopologs and kinematic analysis on deuterated platinum surfaces confirmed the dynamic abstraction mechanism. The instantaneous fractionation process is independent of the surface temperature and may operate on the surface of cometary nuclei or dust grains, composed of deuterium-rich silicates and carbonaceous chondrites. The requisite energetic water ions have been detected in the coma of 67P in two populations. This dynamic fractionation process may temporarily increase the water D/H ratio, especially as the comet gets closer to the Sun. The magnitude of the effect depends on the water ion energy-flux and the deuterium content of the exposed cometary surfaces.« less

Vacuum-surface flashover switch with cantilever conductors

DOEpatents

Caporaso, George J.; Sampayan, Stephen E.; Kirbie, Hugh C.

2001-01-01

A dielectric-wall linear accelerator is improved by a high-voltage, fast rise-time switch that includes a pair of electrodes between which are laminated alternating layers of isolated conductors and insulators. A high voltage is placed between the electrodes sufficient to stress the voltage breakdown of the insulator on command. A light trigger, such as a laser, is focused along at least one line along the edge surface of the laminated alternating layers of isolated conductors and insulators extending between the electrodes. The laser is energized to initiate a surface breakdown by a fluence of photons, thus causing the electrical switch to close very promptly. Such insulators and lasers are incorporated in a dielectric wall linear accelerator with Blumlein modules, and phasing is controlled by adjusting the length of fiber optic cables that carry the laser light to the insulator surface.

Deuterium uptake and sputtering of simultaneous lithiated, boronized, and oxidized carbon surfaces irradiated by low-energy deuterium

NASA Astrophysics Data System (ADS)

Domínguez-Gutiérrez, F. J.; Krstić, P. S.; Allain, J. P.; Bedoya, F.; Islam, M. M.; Lotfi, R.; van Duin, A. C. T.

2018-05-01

We study the effects of deuterium irradiation on D-uptake by simultaneously boronized, lithiated, oxidized, and deuterated carbon surfaces. We present analysis of the bonding chemistry of D for various concentrations of boron, lithium, oxygen, and deuterium on carbon surfaces using molecular dynamics with reactive force field potentials, which are here adapted to include the interaction of boron and lithium. We calculate D retention and sputtering yields of each constituent of the Li-C-B-O mixture and discuss the role of oxygen in these processes. The extent of the qualitative agreement between new experimental data for B-C-O-D obtained in this paper and computational data is provided. As in the case of the Li-C-O system, comparative studies where experimental and computational data complement each other (in this case on the B-Li-C-O system) provide deeper insights into the mechanisms behind the role that O plays in the retention of D, a relevant issue in fusion machines.

Investigation of the delay time distribution of high power microwave surface flashover

NASA Astrophysics Data System (ADS)

Foster, J.; Krompholz, H.; Neuber, A.

2011-01-01

Characterizing and modeling the statistics associated with the initiation of gas breakdown has proven to be difficult due to a variety of rather unexplored phenomena involved. Experimental conditions for high power microwave window breakdown for pressures on the order of 100 to several 100 torr are complex: there are little to no naturally occurring free electrons in the breakdown region. The initial electron generation rate, from an external source, for example, is time dependent and so is the charge carrier amplification in the increasing radio frequency (RF) field amplitude with a rise time of 50 ns, which can be on the same order as the breakdown delay time. The probability of reaching a critical electron density within a given time period is composed of the statistical waiting time for the appearance of initiating electrons in the high-field region and the build-up of an avalanche with an inherent statistical distribution of the electron number. High power microwave breakdown and its delay time is of critical importance, since it limits the transmission through necessary windows, especially for high power, high altitude, low pressure applications. The delay time distribution of pulsed high power microwave surface flashover has been examined for nitrogen and argon as test gases for pressures ranging from 60 to 400 torr, with and without external UV illumination. A model has been developed for predicting the discharge delay time for these conditions. The results provide indications that field induced electron generation, other than standard field emission, plays a dominant role, which might be valid for other gas discharge types as well.

Study of ion-irradiated tungsten in deuterium plasma

NASA Astrophysics Data System (ADS)

Khripunov, B. I.; Gureev, V. M.; Koidan, V. S.; Kornienko, S. N.; Latushkin, S. T.; Petrov, V. B.; Ryazanov, A. I.; Semenov, E. V.; Stolyarova, V. G.; Danelyan, L. S.; Kulikauskas, V. S.; Zatekin, V. V.; Unezhev, V. N.

2013-07-01

Experimental study aimed at investigation of neutron induced damage influence on fusion reactor plasma facing materials is reported. Displacement damage was produced in tungsten by high-energy helium and carbon ions at 3-10 MeV. The reached level of displacement damage ranged from several dpa to 600 dpa. The properties of the irradiated tungsten were studied in steady-state deuterium plasma on the LENTA linear divertor simulator. Plasma exposures were made at 250 eV of ion energy to fluence 1021-1022 ion/сm2. Erosion dynamics of the damaged layer and deuterium retention were observed. Surface microstructure modifications and important damage of the 5 μm layer shown. Deuterium retention in helium-damaged tungsten (ERD) showed its complex behavior (increase or decrease) depending on implanted helium quantity and the structure of the surface layer.

Irradiation effect on deuterium behaviour in low-dose HFIR neutron-irradiated tungsten

DOE PAGES

Shimada, Masashi; Cao, G.; Otsuka, T.; ...

2014-12-01

Tungsten samples were irradiated by neutrons in the High Flux Isotope Reactor, Oak Ridge National Laboratory at reactor coolant temperatures of 50-70°C to low displacement damage of 0.025 and 0.3 dpa under the framework of the US-Japan TITAN program (2007-2013). After cooling down, the HFIR neutron-irradiated tungsten samples were exposed to deuterium plasmas in the Tritium Plasma Experiment, Idaho National Laboratory at 100, 200 and 500 °C twice at the ion fluence of 5×10²⁵ m⁻² to reach a total ion fluence of 1×10²⁶ m⁻² in order to investigate the near surface deuterium retention and saturation via nuclear reaction analysis. Finalmore » thermal desorption spectroscopy was performed to elucidate irradiation effect on total deuterium retention. Nuclear reaction analysis results showed that the maximum near surface (<5 µm depth) deuterium concentration increased from 0.5 at % D/W in 0.025 dpa samples to 0.8 at. % D/W in 0.3 dpa samples. The large discrepancy between the total retention via thermal desorption spectroscopy and the near surface retention via nuclear reaction analysis indicated the deuterium was migrated and trapped in bulk (at least 50 µm depth for 0.025 dpa and 35 µm depth for 0.025 dpa) at 500 °C case even in the relatively low ion fluence of 10²⁶ m⁻².« less

Physicochemical Processes on Ice Dust Towards Deuterium Enrichment

NASA Astrophysics Data System (ADS)

Watanabe, Naoki

2017-06-01

Water and some organic molecules were found to be deuterium enriched toward various astronomical targets. Understanding the deuterium-fractionation process pertains directly to know how and when molecules are created. Although gas phase chemistry is certainly important for deuterium enrichment, the role of physicochemical processes on the dust surfaces should be also considered. In fact, the extreme deuterium enrichment of formaldehyde and methanol requires the dust grain-surface process. In this context, we have performed a series of experiments on the formation of deuterated species of water and simple organic molecules. From the results of these experiments and related works, I will discuss the key processes for the deuterium enrichment on dust. For deuterium chemistry, another important issue is the ortho-to-para ratio (OPR) of H_{2}, which is closely related to the formation of H_{2}D^{+} and thus the deuterium fractionation of molecules in the gas phase. Because the radiative nuclear spin conversion of H_{2} is forbidden, the ortho-para conversion is very slow in the gas phase. In contrast, it was not obvious how the nuclear spins behave on cosmic dust. Therefore, it is desirable to understand how the OPR of H_{2} is determined on the dust surfaces. We have tackled this issue experimentally. Using experimental techniques of molecular beam, photostimulated-desorption, and resonance-enhanced multiphoton ionization, we measured the OPRs of H_{2} photodesorbed from amorphous solid water at around 10 K, which is an ice dust analogue. It was first demonstrated that the rate of spin conversion from ortho to para drastically increases from 2.4 × 10^{-4} to 1.7 × 10^{-3} s^{-1} within the very narrow temperature window of 9.2 to16 K. The observed strong temperature cannot be explained by solely state-mixing models ever proposed but by the energy dissipation model via two phonon process. I will present our recent experiments regarding this.

Deuterium retention in tungsten in dependence of the surface conditions

NASA Astrophysics Data System (ADS)

Ogorodnikova, O. V.; Roth, J.; Mayer, M.

2003-03-01

The paper reviews hydrogen isotope retention and migration in tungsten (W). Due to a large scatter of the deuterium (D) retention database, new measurements of ion-driven D retention in polycrystalline W foil have been performed to clarify the mechanism of hydrogen isotope inventory in W. Deuterium retention has been investigated as a function of ion fluence, implantation temperature, incident energy and surface conditions. Special attention has been given on the investigation of D retention in thin films of tungsten carbide and tungsten oxide which can be formed on W surface in a fusion device. Such kinds of films increase the D retention in W. Several points are reviewed: (i) inventory in pure W, (ii) inventory in W pre-implanted by carbon ions and (iii) inventory in tungsten oxide.

Research on plasma-puff initiation of high Coulomb transfer switches

NASA Technical Reports Server (NTRS)

Venable, Demetrius D.; Han, Kwang S.

1993-01-01

The plasma-puff triggering mechanism based on hypocycloidal pinch geometry was investigated to determine the optimal operating conditions for an azimuthally uniform surface flashover which initiates plasma-puff under wide ranges of fill gas pressures of Ar, He and N2. Research is presented and resulting conference papers are attached. These papers include 'Characteristics of Plasma-Puff Trigger for an Inverse-Pinch Plasma Switch'; 'Ultra-High-Power Plasma Switch INPUTS for Pulse Power Systems'; 'Characteristics of Switching Plasma in an Inverse-Pinch Switch'; 'Comparative Study of INPIStron and Spark Gap'; and 'INPIStron Switched Pulsed Power for Dense Plasma Pinches.'

The Principle and the Application of Self-cleaning Anti-pollution Coating in Power System

NASA Astrophysics Data System (ADS)

Zhao, Y. J.; Zhang, Z. B.; Liu, Y.; Wang, J. H.; Teng, J. L.; Wu, L. S.; Zhang, Y. L.

2017-11-01

The common problem existed in power system is analyzed in this paper. The main reason for the affection of the safe and stable operation to power equipment is flash-over caused by dirt and discharge. Using the self-cleaning anti-pollution coating in the power equipment surface is the key to solve the problem. In the work, the research progress and design principle about the self-cleaning anti-pollution coating was summarized. Furthermore, the preparation technology was also studied. Finally, the application prospect of hard self-cleaning anti-pollution coating in power system was forecast.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kozioziemski, B.

A foam shell, 1.2 mm outer diameter with a 35 μm thick foam layer, is used to quickly form a solid deuterium layer for ICF. Figures show the visible light microscope image and a corresponding schematic representation. In each case, images show the empty foam shell, with the dark and light patches due to the foam imperfections; the foam shell with liquid deuterium filling the foam (in this case, the liquid level exceeds the foam level because the deuterium will shrink when it freezes); and an image of the shell taken 10 minutes after the center image, after the temperaturemore » was reduced by 2 K to freeze the deuterium. This image shows that the majority of the solid deuterium has no observable defects, with the exception of the isolated crystal that formed on the foam surface. The next step is to get the correct level of liquid and cooling rate to prevent the extra crystal on the surface. In contrast, typical ICF DT fuel layers require ~13 hours to solidify in order to be defect free with a success rate of approximately 20%.« less

Selective deuterium ion acceleration using the Vulcan petawatt laser

NASA Astrophysics Data System (ADS)

Krygier, A. G.; Morrison, J. T.; Kar, S.; Ahmed, H.; Alejo, A.; Clarke, R.; Fuchs, J.; Green, A.; Jung, D.; Kleinschmidt, A.; Najmudin, Z.; Nakamura, H.; Norreys, P.; Notley, M.; Oliver, M.; Roth, M.; Vassura, L.; Zepf, M.; Borghesi, M.; Freeman, R. R.

2015-05-01

We report on the successful demonstration of selective acceleration of deuterium ions by target-normal sheath acceleration (TNSA) with a high-energy petawatt laser. TNSA typically produces a multi-species ion beam that originates from the intrinsic hydrocarbon and water vapor contaminants on the target surface. Using the method first developed by Morrison et al. [Phys. Plasmas 19, 030707 (2012)], an ion beam with >99% deuterium ions and peak energy 14 MeV/nucleon is produced with a 200 J, 700 fs, > 10 20 W / cm 2 laser pulse by cryogenically freezing heavy water (D2O) vapor onto the rear surface of the target prior to the shot. Within the range of our detectors (0°-8.5°), we find laser-to-deuterium-ion energy conversion efficiency of 4.3% above 0.7 MeV/nucleon while a conservative estimate of the total beam gives a conversion efficiency of 9.4%.

Trapping state of hydrogen isotopes in carbon and graphite investigated by thermal desorption spectrometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Atsumi, H.; Tanabe, T.; Shikama, T.

Thermal desorption spectrometry (TDS) has been investigated to obtain fundamental information of tritium behavior in graphite and carbon materials especially at high temperatures. 29 brands of graphite, HOPG, glassy carbon and CFC materials charged with deuterium gas are tested up to the temperature of 1735 K with a heating rate of 0.1 K/s. TDS spectra have five peaks at 600-700 K, around 900 K, 1200 K, 1300-1450 K and 1600-1650 K. The amounts of released deuterium have been compared with crystallographic parameters derived from XRD analysis. The results can be summarized as follows. First, TDS spectra of deuterium were quitemore » varied among the samples tested, such as existence of peaks, peak temperatures and release amounts of deuterium. Secondly, TDS spectra may consist of five peaks, which are peak 1 (600-700 K), peak 2 (around 900 K), peak 3 (around 1200 K), peak 4 (1300-1450 K) and peak 5 (1600-1650 K). Thirdly, the correlations between the estimated surface area of edge surface and the total amount of released deuterium could be observed for peaks 4 and 5. Fourthly, high energy trapping site (peak 5) may exist even at edge surface or a near surface region, not only for intercalary. And fifth, in order to obtain the lower tritium retention for graphite and CFC materials, the material should be composed of a filler grain with a smaller crystallite size or having the smaller net edge surface in its structure. It is shown that heat treatment does not reduce originally existing trapping sites but trapping sites generated by neutron irradiation for instance can be reduced in some degree.« less

Micro-NRA and micro-3HIXE with 3He microbeam on samples exposed in ASDEX Upgrade and Pilot-PSI machines

NASA Astrophysics Data System (ADS)

Kelemen, Mitja; Založnik, Anže; Vavpetič, Primož; Pečovnik, Matic; Pelicon, Primož; Hakola, Antti; Lahtinen, Aki; Karhunen, Juuso; Piip, Kaarel; Paris, Peeter; Laan, Matti; Krieger, Karl; Oberkofler, Martin; van der Meiden, Hennie; Markelj, Sabina

2017-08-01

Micro nuclear reaction analysis (micro-NRA) exploiting the nuclear reaction D(3He,p)4He was used for post-mortem analyses of special marker samples, exposed to deuterium plasma inside ASDEX Upgrade (AUG) tokamak and to the deuterium plasma jet in the Pilot-PSI linear plasma gun. Lateral concentration profiles of deuterium and erosion/deposition profiles of the marker materials were obtained by a combination of micro-NRA and particle induced X-ray emission by 3He beam (3HIXE). In the case of AUG samples, where 25 nm thick W marker layers had been deposited on unpolished and polished graphite substrates, the effect of surface roughness on local erosion and deposition was also investigated. The lateral distribution of W concentration showed that erosion is much more distinct in the case of polished samples and the resulting surface shows a ;leopard; skin pattern of W accumulated on carbon aggregates left on the surface from polishing. The Pilot-PSI samples indicated preferential accumulation of deuterium a few mm off from the centre of the region affected by the plasma beam. This is connected with the largest surface modifications while the thick deposited layers at the centre do not favour deuterium retention per se. The results were cross correlated with those obtained using laser-induced breakdown spectroscopy (LIBS). With its quantitative abilities, micro-NRA provided essential calibration data for in situ LIBS operation, as well as for complementary post mortem Secondary Ion Mass Spectroscopy (SIMS).

Rotating Aperture System

DOEpatents

Rusnak, Brian; Hall, James M.; Shen, Stewart; Wood, Richard L.

2005-01-18

A rotating aperture system includes a low-pressure vacuum pumping stage with apertures for passage of a deuterium beam. A stator assembly includes holes for passage of the beam. The rotor assembly includes a shaft connected to a deuterium gas cell or a crossflow venturi that has a single aperture on each side that together align with holes every rotation. The rotating apertures are synchronized with the firing of the deuterium beam such that the beam fires through a clear aperture and passes into the Xe gas beam stop. Portions of the rotor are lapped into the stator to improve the sealing surfaces, to prevent rapid escape of the deuterium gas from the gas cell.

Erosion and deuterium retention of CLF-1 steel exposed to deuterium plasma

NASA Astrophysics Data System (ADS)

Qiao, L.; Wang, P.; Hu, M.; Gao, L.; Jacob, W.; Fu, E. G.; Luo, G. N.

2017-12-01

In recent years reduced activation ferritic martensitic steel has been proposed as the plasma-facing material in remote regions of the first wall. This study reports the erosion and deuterium retention behaviours in CLF-1 steel exposed to deuterium (D) plasma in a linear experimental plasma system as function of incident ion energy and fluence. The incident D ion energy ranges from 30 to 180 eV at a flux of 4 × 1021 D m-2 s-1 up to a fluence of 1025 D m-2. SEM images revealed a clear change of the surface morphology as functions of incident fluence and impinging energy. The mass loss results showed a decrease of the total sputtering yield of CLF-1 steel with increasing incident fluence by up to one order of magnitude. The total sputtering yield of CLF-1 steel after 7.2 × 1024 D m-2 deuterium plasma exposure reduced by a factor of 4 compared with that of pure iron, which can be attributed to the enrichment of W at the surface due to preferential sputtering of iron and chromium. After D plasma exposure, the total deuterium retention in CLF-1 steel samples measured by TDS decreased with increasing incident fluence and energy, and a clear saturation tendency as function of incident fluence or energy was also observed.

Influence of the Groove on Barrier Surface on Creeping Discharge Characteristics in N2 Gas under µs Pulse Voltage

NASA Astrophysics Data System (ADS)

Ueno, Hideki; Kawano, Taichi; Sakamoto, Naoki; Nakayama, Hiroshi

For a needle-plane electrode system with a barrier, which establishes the electric field across the axis of a groove, creeping discharge characteristics in N2 gas under µs pulse voltage applications have been investigated. The distance h between the barrier surface and the needle tip as well as the distance M between the groove center and the needle tip were changed. In the case of h=0.3mm, when the needle tip is located near the far-side groove edge from the plane electrode (M=0.6mm), the flashover voltage has the maximum value. At that time, a growth of a corona is suppressed near the groove edge. These unique characteristics should associate with a field relaxation.

A multi-technique analysis of deuterium trapping and near-surface precipitate growth in plasma-exposed tungsten

DOE PAGES

Kolasinski, Robert; Shimada, Masashi; Oya, Yasuhisa; ...

2015-08-17

We examine how deuterium becomes trapped in plasma-exposed tungsten and forms near-surface platelet-shaped precipitates. How these bubbles nucleate and grow, as well as the amount of deuterium trapped within, is crucial for interpreting the experimental database. Here, we use a combined experimental/theoretical approach to provide further insight into the underlying physics. With the Tritium Plasma Experiment, we exposed a series of ITER-gradetungsten samples to high flux D plasmas (up to 1.5 × 10 22 m -2 s -1) at temperatures ranging between 103 and 554 °C. Retention of deuterium trapped in the bulk, assessed through thermal desorption spectrometry, reached amore » maximum at 230 °C and diminished rapidly thereafter for T > 300 °C. Post-mortem examination of the surfaces revealed non-uniform growth of bubbles ranging in diameter between 1 and 10 μm over the surface with a clear correlation with grain boundaries. Electron back-scattering diffraction maps over a large area of the surface confirmed this dependence; grains containing bubbles were aligned with a preferred slip vector along the <111> directions. Focused ion beam profiles suggest that these bubbles nucleated as platelets at depths of 200 nm–1 μm beneath the surface and grew as a result of expansion of sub-surface cracks. Furthermore, to estimate the amount of deuterium trapped in these defects relative to other sites within the material, we applied a continuum-scale treatment of hydrogen isotope precipitation. Additionally, we propose a straightforward model of near-surface platelet expansion that reproduces bubble sizes consistent with our measurements. For the tungsten microstructure considered here, we find that bubbles would only weakly affect migration of D into the material, perhaps explaining why deep trapping was observed in prior studies with plasma-exposed neutron-irradiated specimens. We foresee no insurmountable issues that would prevent the theoretical framework developed here from being extended to a broader range of systems where precipitation of insoluble gases in ion beam or plasma-exposed metals is of interest.« less

Development of a head-phantom and measurement setup for lightning effects.

PubMed

Machts, Rene; Hunold, Alexander; Leu, Carsten; Haueisen, Jens; Rock, Michael

2016-08-01

Direct lightning strikes to human heads lead to various effects ranging from Lichtenberg figures, over loss of consciousness to death. The evolution of the induced current distribution in the head is of great interest to understand the effect mechanisms. This work describes a technique to model a simplified head-phantom to investigate effects during direct lightning strike. The head-phantom geometry, conductive and dielectric parameters were chosen similar to that of a human head. Three layers (brain, skull, and scalp) were created for the phantom using agarose hydrogel doped with sodium chloride and carbon. The head-phantom was tested on two different impulse generators, which reproduce approximate lightning impulses. The effective current and the current distribution in each layer were analyzed. The biggest part of the current flowed through the brain layer, approx. 70 % in cases without external flashover. Approx. 23 % of the current flowed through skull layer and 6 % through the scalp layer. However, the current decreased within the head-phantom to almost zero after a complete flashover on the phantom occurred. The flashover formed faster with a higher impulse current level. Exposition time of current through the head decreases with a higher current level of the lightning impulse. This mechanism might explain the fact that people can survive a lightning strike. The experiments help to understand lightning effects on humans.

Finite element probabilistic risk assessment of transmission line insulation flashovers caused by lightning strokes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bacvarov, D.C.

1981-01-01

A new method for probabilistic risk assessment of transmission line insulation flashovers caused by lightning strokes is presented. The utilized approach of applying the finite element method for probabilistic risk assessment is demonstrated to be very powerful. The reasons for this are two. First, the finite element method is inherently suitable for analysis of three dimensional spaces where the parameters, such as three variate probability densities of the lightning currents, are non-uniformly distributed. Second, the finite element method permits non-uniform discretization of the three dimensional probability spaces thus yielding high accuracy in critical regions, such as the area of themore » low probability events, while at the same time maintaining coarse discretization in the non-critical areas to keep the number of grid points and the size of the problem to a manageable low level. The finite element probabilistic risk assessment method presented here is based on a new multidimensional search algorithm. It utilizes an efficient iterative technique for finite element interpolation of the transmission line insulation flashover criteria computed with an electro-magnetic transients program. Compared to other available methods the new finite element probabilistic risk assessment method is significantly more accurate and approximately two orders of magnitude computationally more efficient. The method is especially suited for accurate assessment of rare, very low probability events.« less

Hydrogen-deuterium substitution in solid ethanol by surface reactions at low temperatures

NASA Astrophysics Data System (ADS)

Oba, Yasuhiro; Osaka, Kazuya; Chigai, Takeshi; Kouchi, Akira; Watanabe, Naoki

2016-10-01

Ethanol (CH3CH2OH) is one of the most abundant complex organic molecules in star-forming regions. Despite its detection in the gas phase only, ethanol is believed to be formed by low-temperature grain-surface reactions. Methanol, the simplest alcohol, has been a target for observational, experimental, and theoretical studies in view of its deuterium enrichment in the interstellar medium; however, the deuterium chemistry of ethanol has not yet been an area of focus. Recently, deuterated dimethyl ether, a structural isomer of ethanol, was found in star-forming regions, indicating that deuterated ethanol can also be present in those environments. In this study, we performed laboratory experiments on the deuterium fractionation of solid ethanol at low temperatures through a reaction with deuterium (D) atoms at 10 K. Hydrogen (H)-D substitution, which increases the deuteration level, was found to occur on the ethyl group but not on the hydroxyl group. In addition, when deuterated ethanol (e.g. CD3CD2OD) solid was exposed to H atoms at 10 K, D-H substitution that reduced the deuteration level occurred on the ethyl group. Based on the results, it is likely that deuterated ethanol is present even under H-atom-dominant conditions in the interstellar medium.

Diffusion of hydrogen in a hydrogen-saturated tungsten

NASA Astrophysics Data System (ADS)

Krstic, Predrag; Kaganovich, Igor

2015-11-01

Hydrogen diffusion in monoscrystalline tungsten is studied by molecular dynamics with BOP potential in function of hydrogen concentration and temperature. Tungsten surface is prepared by cumulative irradiation of the 25 eV deuterium atoms at various fluences. The diffusion coefficients for T>500K and various D concentrations were calculated from the average slope of the mean square displacements of deuterium as functions of time. The accumulation of deuterium suppresses its diffusion at all temperatures. The results are in a reasonable agreement with the existing experiments. Supported by the LDRD of PPPL.

Surface modification and deuterium retention in reduced-activation steels exposed to low-energy, high-flux pure and helium-seeded deuterium plasmas

NASA Astrophysics Data System (ADS)

Alimov, V. Kh; Ogorodnikova, O. V.; Hatano, Y.; Gasparyan, YuM.; Efimov, V. S.; Mayer, M.; Zhou, Z.; Oyaizu, M.; Isobe, K.; Nakamura, H.; Hayashi, T.

2018-04-01

Surface topography of and deuterium (D) retention in reduced activation ferritic-martensitic Eurofer'97 and ferritic oxide dispersion strengthening ODS-16Cr steels have been studied after exposure at 600 K to low-energy (70 and 200 eV), high-flux (∼1022 D/m2s) pure D and D-10%He plasmas with D fluence of 2 × 1025 D/m2. The methods used were scanning electron microscopy, energy-scanning D(3He,p)4He nuclear reaction, and thermal desorption spectroscopy. As a result of the plasma exposures, nano-sized structures are formed on the steel surfaces. After exposure to pure D plasmas, a significant fraction of D is accumulated in the bulk, at depths larger than 8 μm. After exposures to D-He plasmas, D is retained mainly in the near-surface layers. In spite of the fact that the He fluence was lower than the D fluence, the He retention in the steels is one order of magnitude higher than the D retention.

A Solid-State Deuterium NMR and SFG Study of the Side Chain Dynamics of Peptides Adsorbed onto Surfaces

PubMed Central

Breen, Nicholas F.; Weidner, Tobias; Li, Kun; Castner, David G.; Drobny, Gary P.

2011-01-01

The artificial amphiphilic peptide LKα14 adopts a helical structure at interfaces, with opposite orientation of its leucine (L, hydrophobic) and lysine (K, hydrophilic) side chains. When adsorbed onto surfaces, different residue side chains necessarily have different proximities to the surface, depending on both their position in the helix and the composition of the surface itself. Deuterating the individual leucine residues (isopropyl-d7) permits the use of solid-state deuterium NMR as a site-specific probe of side chain dynamics. In conjunction with SFG as a probe of the peptide binding face, we demonstrate that the mobility of specific leucine side chains at the interface is quantifiable in terms of their surface proximity. PMID:19764755

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tewari, Somesh Vinayak, E-mail: somesh-vinayak@yahoo.com, E-mail: svtewari@barc.gov.in; Sharma, Archana; Mittal, K. C.

An experimental investigation of surface flashover characteristics of PMMA and POM is studied in compressed nitrogen gas environment with nitrogen as the background gas. The operating pressure range is from 1kg/cm{sup 2} to 4kg/cm{sup 2}. It is observed that the breakdown voltage of PMMA is higher than POM owing to a higher permittivity mismatch between POM- nitrogen interface as compared to the PMMA- nitrogen interface. The reduction in spacer efficiency with pressure for PMMA is 11% as compared to POM which shows a higher reduction of 18%. This paper further emphasizes on the role of energy level and density ofmore » charge carrier trapping centers for a reduced breakdown voltage in POM as compared to PMMA.« less

Formation of hydrophobic coating on glass surface using atmospheric pressure non-thermal plasma in ambient air

NASA Astrophysics Data System (ADS)

Fang, Z.; Qiu, Y.; Kuffel, E.

2004-08-01

Non-thermal plasmas under atmospheric pressure are of great interest in material surface processing because of their convenience, effectiveness and low cost. In this paper, the treatment of a glass surface for improving hydrophobicity using a non-thermal plasma generated by a dielectric barrier corona discharge (DBCD) with a needle array-to-plane electrode arrangement in atmospheric air is conducted, and the surface properties of the glass before and after the DBCD treatment are studied using contact angle measurement, surface resistance measurement and the wet flashover voltage test. The effects of the plasma dose (the product of average discharge power and treatment time) of DBCD on the surface modification are studied, and the mechanism of interaction between the plasma and glass surface is discussed. It is found that a layer of hydrophobic coating is formed on the glass surface through DBCD treatment, and the improvement of hydrophobicity depends on the plasma dose of the DBCD. It seems that there is an optimum plasma dose for the surface treatment. The test results of thermal ageing and chemical ageing show that the hydrophobic layer has quite stable characteristics.

Permeation of deuterium implanted into V-15Cr-5Ti

NASA Astrophysics Data System (ADS)

Anderl, R. A.; Longhurst, G. R.; Struttmann, D. A.

1987-02-01

Permeation and reemission of deuterium for the vanadium alloy, V-15Cr-5Ti, was investigated using 3 keV, D 3+ ion beams from a small accelerator. The experiments consisted of measurement of the deuterium reemission and permeation rates as a function of implantation fluence for 0.5 mm thick specimens heated to temperatures from 623 K to 823 K. Implantation-side surface characterization was made by simultaneous measurements of sputtered ions with a secondary ion mass spectrometer (SIMS). For the experimental conditions used, the steady-state deuterium permeation flux in V-15Cr-5Ti is approximately 18% of the implantation flux. This is approximately 1000 times that seen in the austenitic stainless steel, PCA, and 200 times that seen in the ferritic steel, HT-9, under comparable conditions. Measurement of deuterium diffusivity in V-15Cr-5Ti using permeation break-through times indicates that D = 1.4 × 10 -8 exp( -0.11 eV/ kT) (m 2/s), over the temperature range 723 K to 823 K.

Pulsed Plasma Electron Sources

NASA Astrophysics Data System (ADS)

Krasik, Yakov

2008-11-01

Pulsed (˜10-7 s) electron beams with high current density (>10^2 A/cm^2) are generated in diodes with electric field of E > 10^6 V/cm. The source of electrons in these diodes is explosive emission plasma, which limits pulse duration; in the case E < 10^5 V/cm this plasma is not uniform and there is a time delay in its formation. Thus, there is a continuous interest in research of electron sources which can be used for generation of uniform electron beams produced at E <= 10^5 V/cm. In the present report, several types of plasma electron source (PES) will be considered. The first type of PES is fiber-based cathodes, with and without CsI coating. The operation of these cathodes is governed by the formation of the flashover plasma which serves as a source of electrons. The second type of PES is the ferroelectric plasma source (FPS). The operation of FPS, characterized by the formation of dense surface flashover plasma is accompanied also by the generation of fast microparticles and energetic neutrals. The latter was explained by Coulomb micro-explosions of the ferroelectric surface due to an large time-varying electric field at the front of the expanding plasma. A short review of recent achievements in the operation of a multi-FPS-assisted hollow anode to generate a large area electron beam will be presented as well. Finally, parameters of the plasma produced by a multi-capillary cathode with FPS and velvet igniters will be discussed. Ya. E. Krasik, J. Z. Gleizer, D. Yarmolich, A. Krokhmal, V. Ts. Gurovich, S.Efimov, J. Felsteiner V. Bernshtam, and Yu. M. Saveliev, J. Appl. Phys. 98, 093308 (2005). Ya. E. Krasik, A. Dunaevsky, and J. Felsteiner, Phys. Plasmas 8, 2466 (2001). D. Yarmolich, V. Vekselman, V. Tz. Gurovich, and Ya. E. Krasik, Phys. Rev. Lett. 100, 075004 (2008). J. Z. Gleizer, Y. Hadas and Ya. E. Krasik, Europhysics Lett. 82, 55001 (2008).

Coupled interactions between tungsten surfaces and transient high-heat-flux deuterium plasmas

NASA Astrophysics Data System (ADS)

Takamura, S.; Uesugi, Y.

2015-03-01

Fundamental studies on the interactions between transient deuterium-plasma heat pulses and tungsten surfaces were carried out in terms of electrical, mechanical and thermal response in a compact plasma device AIT-PID (Aichi Institute of Technology-Plasma Irradiation Device). Firstly, electron-emission-induced surface-temperature increase is discussed in the surface-temperature range near tungsten's melting point, which is accomplished by controlling the sheath voltage and power transmission factor. Secondly, anomalous penetration of tungsten atomic efflux into the surrounding plasma was observed in addition to a normal layered population; it is discussed in terms of the effect of substantial tungsten influx into the deuterium plasma, which causes dissipation of plasma electron energy. Thirdly, a momentum input from pulsed plasma onto a tungsten target was observed visually. The force is estimated numerically by the accelerated ion flow to the target as well as the reaction of tungsten-vapour efflux. Finally, a discussion follows on the effects of the plasma heat pulses on the morphology of tungsten surface (originally a helium-induced ‘fuzzy’ nanostructure). A kind of bifurcated effect is obtained: melting and annealing. Open questions remain for all the phenomena observed, although sheath-voltage-dependent plasma-heat input may be a key parameter. Discussions on all these phenomena are provided by considering their implications to tokamak fusion devices.

Blistering behavior and deuterium retention in tungsten vanadium alloys exposed to deuterium plasma in the linear plasma device STEP

NASA Astrophysics Data System (ADS)

Wang, Jun; Cheng, Long; Yuan, Yue; Qin, Shao-Yang; Arshad, Kameel; Guo, Wang-Guo; Wang, Zheng; Zhou, Zhang-Jian; Lu, Guang-Hong

2018-03-01

The behavior of tungsten-vanadium (W-V) alloys fabricated by powder metallurgy as a plasma facing material has been studied. W-V alloys with different vanadium concentrations (5 and 10 wt %) manufactured by hot pressing (HP) were exposed to deuterium plasma (flux ∼4.6 × 1021 m-2s-1, fluence ∼5.6 × 1025 m-2, ion energy ∼60 eV, target temperature ∼450 K) in the linear plasma device STEP at Beihang University. Three typical grains are observed on HP sintered W-V alloys and exhibit a significant effect on its performance under deuterium plasma irradiation. Surface blistering only occurs at W-enriched grains and is significantly mitigated in W-V alloys, especially in W-10 V, blistering is completely suppressed. On the other hand, deuterium retention dramatically increases in the W-V alloys due to vanadium addition. The deuterium retention in W-5 wt. % V is about 6.2 times more than that in rolled pure W, and this factor further increases to 6.9 when the V concentration rises to 10 wt %. We ascribe these phenomena to the changes of microstructures and components caused by vanadium addition.

Results Of Insulation Resistance Between Solar Cell String Gaps Without RTV Adhesive Grout After Electrostatic Discharge Tests With Cover Glass Flashover

NASA Astrophysics Data System (ADS)

Hoang, Bao; Wong, Frankie; Redick, Tod; Masui, Hirokazu; Endo, Taishi; Toyoda, Kazuhiro; Cho, Mengu

2011-10-01

A series of electrostatic discharge (ESD) tests was performed on solar array test coupons consisting of Advanced Triple Junction InGaP2/InGaAs/Ge solar cells. The motivation for these tests was to evaluate the effects of ESD on solar array design without room temperature vulcanized (RTV) adhesive grout between the string-to-string parallel gaps. To investigate the threshold of permanently sustained secondary arcs, various combinations of gap width, load voltage and string current were tested in a vacuum chamber equipped with an electron beam gun. This ESD test program included the ESD test circuit with simulated panel coverglass flashover. Although ESD events did not result in permanent sustained arcs, the insulation resistance between strings was found to decrease as the number of secondary arcs accumulated in the gap.

Analysis of the silicone polymer surface aging profile with laser-induced breakdown spectroscopy

NASA Astrophysics Data System (ADS)

Wang, Xilin; Hong, Xiao; Wang, Han; Chen, Can; Zhao, Chenlong; Jia, Zhidong; Wang, Liming; Zou, Lin

2017-10-01

Silicone rubber composite materials have been widely used in high voltage transmission lines for anti-pollution flashover. The aging surface of silicone rubber materials decreases service properties, causing loss of the anti-pollution ability. In this paper, as an analysis method requiring no sample preparation that is able to be conducted on site and suitable for nearly all types of materials, laser-induced breakdown spectroscopy (LIBS) was used for the analysis of newly prepared and aging (out of service) silicone rubber composites. With scanning electron microscopy (SEM) and hydrophobicity test, LIBS was proven to be nearly non-destructive for silicone rubber. Under the same LIBS testing parameters, a linear relationship was observed between ablation depth and laser pulses number. With the emission spectra, all types of elements and their distribution in samples along the depth direction from the surface to the inner part were acquired and verified with EDS results. This research showed that LIBS was suitable to detect the aging layer depth and element distribution of the silicone rubber surface.

Irradiation of nuclear materials with laser-plasma filaments produced in air and deuterium by terrawatt (TW) laser pulses

NASA Astrophysics Data System (ADS)

Avotina, Liga; Lungu, Mihail; Dinca, Paul; Butoi, Bogdan; Cojocaru, Gabriel; Ungureanu, Razvan; Marcu, Aurelian; Luculescu, Catalin; Hapenciuc, Claudiu; Ganea, Paul C.; Petjukevics, Aleksandrs; Lungu, Cristian P.; Kizane, Gunta; Ticos, C. M.; Antohe, Stefan

2018-01-01

Be-C-W mixed materials with variable atomic ratios were exposed to high power (TW) laser induced filamentation plasma in air in normal conditions and in deuterium at a reduced pressure of 20 Torr. Morphological and structural investigations were performed on the irradiated zones for both ambient conditions. The presence of low-pressure deuterium increased the overall ablation rate for all samples. From the elemental concentration point of view, the increase of the carbon percentage has led to an increase in the ablation rate. An increase of the tungsten percentage had the opposite effect. From structural spectroscopic investigations using XPS, Raman and FT-IR of the irradiated and non-irradiated sample surfaces, we conclude that deuterium-induced enhancement of the ablation process could be explained by preferential amorphous carbon removal, possibly by forming deuterated hydrocarbons which further evaporated, weakening the layer structure.

Ice core age dating and paleothermometer calibration based on isotope and temperature profiles from deep boreholes at Vostok Station (East Antarctica)

NASA Astrophysics Data System (ADS)

Salamatin, Andrey N.; Lipenkov, Vladimir Y.; Barkov, Nartsiss I.; Jouzel, Jean; Petit, Jean Robert; Raynaud, Dominique

1998-04-01

An interpretation of the deuterium profile measured along the Vostok (East Antarctica) ice core down to 2755 m has been attempted on the basis of the borehole temperature analysis. An inverse problem is solved to infer a local "geophysical metronome," the orbital signal in the surface temperature oscillations expressed as a sum of harmonics of Milankovich periods. By correlating the smoothed isotopic temperature record to the metronome, a chronostratigraphy of the Vostok ice core is derived with an accuracy of ±3.0-4.5 kyr. The developed timescale predicts an age of 241 kyr at a depth of 2760 m. The ratio δD/δTi between deuterium content and cloud temperature fluctuations (at the top of the inversion layer) is examined by fitting simulated and measured borehole temperature profiles. The conventional estimate of the deuterium-temperature slope corresponding to the present-day spatial ratio (9 per mil/°C) is confirmed in general. However, the mismatch between modeled and measured borehole temperatures decreases noticeably if we allow surface temperature, responsible for the thermal state of the ice sheet, to undergo more intensive precession oscillations than those of the inversion temperature traced by isotope record. With this assumption, we obtain the long-term temporal deuterium-temperature slope to be 5.8-6.5 per mil/°C which implies that the glacial-interglacial temperature increase over central Antarctica was about 15°C in the surface temperature and 10°C in the inversion temperature. Past variations of the accumulation rate and the corresponding changes in the ice-sheet surface elevation are simultaneously simulated.

Deuterium depth profile quantification in a ASDEX Upgrade divertor tile using secondary ion mass spectrometry

NASA Astrophysics Data System (ADS)

Ghezzi, F.; Caniello, R.; Giubertoni, D.; Bersani, M.; Hakola, A.; Mayer, M.; Rohde, V.; Anderle, M.; ASDEX Upgrade Team

2014-10-01

We present the results of a study where secondary ion mass spectrometry (SIMS) has been used to obtain depth profiles of deuterium concentration on plasma facing components of the first wall of the ASDEX Upgrade tokamak. The method uses primary and secondary standards to quantify the amount of deuterium retained. Samples of bulk graphite coated with tungsten or tantalum-doped tungsten are independently profiled with three different SIMS instruments. Their deuterium concentration profiles are compared showing good agreement. In order to assess the validity of the method, the integrated deuterium concentrations in the coatings given by one of the SIMS devices is compared with nuclear reaction analysis (NRA) data. Although in the case of tungsten the agreement between NRA and SIMS is satisfactory, for tantalum-doped tungsten samples the discrepancy is significant because of matrix effect induced by tantalum and differently eroded surface (W + Ta always exposed to plasma, W largely shadowed). A further comparison where the SIMS deuterium concentration is obtained by calibrating the measurements against NRA values is also presented. For the tungsten samples, where no Ta induced matrix effects are present, the two methods are almost equivalent.The results presented show the potential of the method provided that the standards used for the calibration reproduce faithfully the matrix nature of the samples.

Interactions of Deuterium Plasma with Lithiated and Boronized Surfaces in NSTX-U

NASA Astrophysics Data System (ADS)

Krstic, Predrag

2015-09-01

The main research goal of the presented research has been to understand the changes in surface composition and chemistry at the nanoscopic temporal and spatial scales for long pulse Plasma Facing Components (PFCs) and link these to the overall machine performance of the National Spherical Torus Experiment Upgrade (NSTX-U). A study is presented of the lithium surface science, with atomic spatial and temporal resolutions. The dynamic surface responds and evolves in a mixed material environments (D, Li, C, B, O, Mo, W) with impingement of plasma particles in the energy range below 100 eV. The results, obtained by quantum-classical molecular dynamics, include microstructure changes, erosion, surface chemistry, deuterium implantation and permeation. Main objectives of the research are i) a comparison of Li and B deposition on carbon, ii) the role of oxygen and other impurities e.g. boron, carbon in the lithium performance, and iii) how this performance will change when lithium is applied to a high-Z refractory metal substrate (Mo, W). In addition to predicting and understanding the phenomenology of the processes, we will show plasma induced erosion of PFCs, including chemical and physical sputtering yields at various temperatures (300-700 K) as well as deuterium uptake/recycling. This work is supported by the U.S. Department of Energy Office of Science, Office of Fusion Energy Science, Award Number DE-SC0013752.

Surface modification and deuterium retention in reduced-activation steels under low-energy deuterium plasma exposure. Part II: steels pre-damaged with 20 MeV W ions and high heat flux

NASA Astrophysics Data System (ADS)

Ogorodnikova, O. V.; Zhou, Z.; Sugiyama, K.; Balden, M.; Pintsuk, G.; Gasparyan, Yu.; Efimov, V.

2017-03-01

The reduced-activation ferritic/martensitic (RAFM) steels including Eurofer (9Cr) and oxide dispersion strengthened (ODS) steels by the addition of Y2O3 particles investigated in Part I were pre-damaged either with 20 MeV W ions at room temperature at IPP (Garching) or with high heat flux at FZJ (Juelich) and subsequently exposed to low energy (~20-200 eV per D) deuterium (D) plasma up to a fluence of 2.9  ×  1025 D m-2 in the temperature range from 290 K to 700 K. The pre-irradiation with 20 MeV W ions at room temperature up to 1 displacement per atom (dpa) has no noticeable influence on the steel surface morphology before and after the D plasma exposure. The pre-irradiation with W ions leads to the same concentration of deuterium in all kinds of investigated steels, regardless of the presence of nanoparticles and Cr content. It was found that (i) both kinds of irradiation with W ions and high heat flux increase the D retention in steels compared to undamaged steels and (ii) the D retention in both pre-damaged and undamaged steels decreases with a formation of surface roughness under the irradiation of steels with deuterium ions with incident energy which exceeds the threshold of sputtering. The increase in the D retention in RAFM steels pre-damaged either with W ions (damage up to ~3 µm) or high heat flux (damage up to ~10 µm) diminishes with increasing the temperature. It is important to mention that the near surface modifications caused by either implantation of high energy ions or a high heat flux load, significantly affect the total D retention at low temperatures or low fluences but have a negligible impact on the total D retention at elevated temperatures and high fluences because, in these cases, the D retention is mainly determined by bulk diffusion.

On nuclear DD synthesis at the initial stage of nanosecond vacuum discharge with deuterium-loaded Pd anode

NASA Astrophysics Data System (ADS)

Kurilenkov, Yu K.; Gus'kov, S. Yu; Karpukhin, V. T.; Oginov, A. V.; Samoylov, I. S.

2018-01-01

Earlier, there was demonstrated generation of DD neutrons in an interelectrode medium of a low-energy (˜ 1 J) nanosecond vacuum discharge with a hollow cathode and a deuterium-loaded Pd anode. There was revealed essential role of formation of a virtual cathode and a potential well corresponding thereto in the processes of collisional DD synthesis in the interelectrode space. In this work, we have obtained as a result of an experiment and discussed the neutron yield at the very initial stage of the discharge, when the beam of auto-electrons just starts to irradiate the non-ideal surface of the deuterium-loaded Pd anode.

UV irradiation experiments under simulated martian surface conditions: Bio-effects on glycine, phage T7 and isolated T7 DNA

NASA Astrophysics Data System (ADS)

Bérces, Attila; ten Kate, I. L.; Fekete, A.; Hegedus, M.; Garry, J. R. C.; Lammer, Helmut; Ehrenfreund, Pascale; Peeters, Zan; Kovacs, G.; Ronto, G.

Mars is considered as a main target for astrobiologically relevant exploration programmes. In order to explain the non-detection of organic material to a detection level of several parts per billion (ppb) by the Viking landers, several hypotheses have been suggested, including degradation processes occurring on the martian surface and in the martian soil and subsurface. UV exposure experiments have been performed in which thin layers of glycine ( 300 nm), and aqueous suspensions of phage T7 and isolated T7 DNA were irradiated with a Deuterium lamp and for comparison with a Xenon arc lamp, modified to simulate the solar irradiation on the surface of Mars (MarsUV). The glycine sample was subjected to 24 hours of irradiation with MarsUV. The results of this glycine experiment show a destruction rate comparable to the results of previous experiments in which thin layers of glycine were irradiated with a deuterium lamp (ten Kate et al., 2005, 2006). After exposure of different doses of simulated Martian UV radiation a decrease of the biological activity of phages and characteristic changes in the UV absorption spectrum have been detected, indicating the UV damage of isolated and intraphage T7 DNA. The results of our experiments show that intraphage DNA is 4 times more sensitive to simulated martian UV and deuterium lamp radiation than isolated T7 DNA. This result indicates the significant role that phage proteins play in the UV damage. The effect of simulated martian radiation is smaller than the biological defects observed after the exposure with a deuterium lamp for both cases, in intraphage and isolated DNA, despite of the 100 times larger intensity of the MarsUV lamp. The detected spectral differences are about ten times smaller; the biological activity is about 3 - 4 times smaller, indicating that the shorter wavelength UV radiation from the deuterium lamp is more effective in inducing DNA damage, irrespective of being intraphage or isolated.

Deuterium trapping in tungsten

NASA Astrophysics Data System (ADS)

Poon, Michael

Tungsten is one of the primary material candidates being investigated for use in the first-wall of a magnetic confinement fusion reactor. An ion accelerator was used to simulate the type of ion interaction that may occur at a plasma-facing material. Thermal desorption spectroscopy (TDS) was the primary tool used to analyze the effects of the irradiation. Secondary ion mass spectroscopy (SIMS) was used to determine the distribution of trapped D in the tungsten specimen. The tritium migration analysis program (TMAP) was used to simulate thermal desorption profiles from the D depth distributions. Fitting of the simulated thermal desorption profiles with the measured TDS results provided values of the D trap energies. Deuterium trapping in single crystal tungsten was studied as a function of the incident ion fluence, ion flux, irradiation temperature, irradiation history, and surface impurity levels during irradiation. The results show that deuterium was trapped at vacancies and voids. Two deuterium atoms could be trapped at a tungsten vacancy, with trapping energies of 1.4 eV and 1.2 eV for the first and second D atoms, respectively. In a tungsten void, D is trapped as atoms adsorbed on the inner walls of the void with a trap energy of 2.1 eV, or as D2 molecules inside the void with a trap energy of 1.2 eV. Deuterium trapping in polycrystalline tungsten was also studied as a function of the incident fluence, irradiation temperature, and irradiation history. Deuterium trapping in polycrystalline tungsten also occurs primarily at vacancies and voids with the same trap energies as in single crystal tungsten; however, the presence of grain boundaries promotes the formation of large surface blisters with high fluence irradiations at 500 K. In general, D trapping is greater in polycrystalline tungsten than in single crystal tungsten. To simulate mixed materials comprising of carbon (C) and tungsten, tungsten specimens were pre-irradiated with carbon ions prior to D irradiation. Deuterium trapping could be characterized by three regimes: (i) enhanced D retention in a graphitic film formed by the C+ irradiation; (ii) decreased D retention in a modified tungsten-carbon layer; and (iii) D retention in pure tungsten.

Electrohydrodynamic behavior of water droplets on a horizontal super hydrophobic surface and its self-cleaning application

NASA Astrophysics Data System (ADS)

Li, Jian; Wei, Yuan; Huang, Zhengyong; Wang, Feipeng; Yan, Xinzhu; Wu, Zhuolin

2017-05-01

Moisture is a significant factor that affects the insulation performance of outdoor high-voltage insulators in power systems. Accumulation of water droplets on insulators causes severe problems such as flashover of insulators and power outage. In this study, we develop a method to fabricate a micro/nano hierarchical super hydrophobic surface. The as-prepared super hydrophobic surface exhibits a water contact angle (WCA) of 160.4 ± 2°, slide angle (SA) less than 1° and surface free energy (SFE) of 5.99 mJ/m2. We investigated the electrohydropdynamic behavior of water droplet on a horizontal super hydrophobic surface compared with hydrophobic RTV silicone rubber surface which was widely used as anti-pollution coating or shed material of composite insulator. Results show that water droplet tended to a self-propelled motion on the super hydrophobic surface while it tended to elongate and break up on the RTV surface. The micro/nano hierarchical surface structure and chemical components with low surface free energy of the super hydrophobic surface jointly contributed to the reduction of skin fraction drag and subsequently made it possible for the motion of water droplet driven by electric field. Furthermore, the self-propelled motion of water droplets could also sweep away contaminations along its moving trace, which provides super hydrophobic surface a promising anti-pollution prospect in power systems.

Laser-induced desorption determinations of surface diffusion on Rh(111)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seebauer, E.G.; Schmidt, L.D.

Surface diffusion of hydrogen, deuterium and CO on Rh(111) has been investigated by laser-induced thermal desorption (LITD) and compared with previous results for these species on Pt(111) and on other metals. For deuterium in the coverage range 0.02 < theta < 0.33, the pre-exponential factor D/sub 0/ - 8 x 10/sup -2/ cm/sup 2//s, with a diffusion activation energy 3.7 < E/sub diff/ < 4.3 kcal/mol. For CO, E/sub diff/ = 7 kcal/mol, but D/sub 0/ rises from 10/sup -3/ to 10/sup -2/ cm/sup 2//s between theta = 0.01 and 0.40. Values of E/sub diff/ on different surfaces appear tomore » correlate with differences in heats of adsorption in different binding states which form saddle point configurations in surface diffusion. In addition, oxidation reactions on Rh and on several other transition metal surfaces may be limited to CO or H surface diffusion. 30 refs., 3 figs., 1 tab.« less

Follow-on to a report on the Applicability of the “Gallet equation” to the vegetation clearances of NERC Reliability Standard FAC-003-2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kirkham, Harold

2012-08-31

In earlier work, a study done at the Pacific Northwest National Laboratory examined a NERC proposed standard specifying clearances between vegetation and power lines. The method proposed for calculating the clearances was based on the results of testing for high-voltage line designs. An equation developed to relate the results of testing with rod-plane gaps to proposed tower window sizes was incorporated into the calculations. The equation in question, sometimes called the “Gallet equation,” describes the insulation performance of the atmosphere for air gaps of a few meters. The equation was described in the PNNL study as a good and simple-to-usemore » way to solve a problem made difficult by the nonlinear interactions of the variables. For calculations based on this equation, a certain set of assumptions must be made. In particular, a value for a quantity called the “gap factor” is needed. This is the amount by which the gap to be modeled by the equation is stronger than the reference gap that was used in developing the Gallet equation. That reference gap is the gap between a rod and a plane. This follow-on report examines the effect on flashover probabilities of assuming an incorrect value for the gap factor. In particular, the flashover probability is found that would result from using a value of 1.3 when a gap factor of 1.0 should be applied. It is shown that with these assumptions the probability of a flashover changes from being extremely unlikely (about 1 in 1000 chance) to a virtual certainty (about 97% chance).« less

Improving Hydrophobicity of Glass Surface Using Dielectric Barrier Discharge Treatment in Atmospheric Air

NASA Astrophysics Data System (ADS)

Fang, Zhi; Qiu, Yuchang; Wang, Hui; E, Kuffel

2007-10-01

Non-thermal plasmas under atmospheric pressure are of great interest in industrial applications, especially in material surface treatment. In this paper, the treatment of a glass surface for improving hydrophobicity using the non-thermal plasma generated by dielectric barrier discharge (DBD) at atmospheric pressure in ambient air is conducted, and the surface properties of the glass before and after the DBD treatment are studied by using contact angle measurement, surface resistance measurement and wet flashover voltage tests. The effects of the applied voltage and time duration of DBD on the surface modification are studied, and the optimal conditions for the treatment are obtained. It is found that a layer of hydrophobic coating is formed on the glass surface after spraying a thin layer of silicone oil and undergoing the DBD treatment, and the improvement of hydrophobicity depends on DBD voltage and treating time. It seems that there exists an optimum treating time for a certain applied voltage of DBD during the surface treatment. The test results of thermal aging and chemical aging show that the hydrophobic layer has quite stable characteristics. The interaction mechanism between the DBD plasma and the glass surface is discussed. It is concluded that CH3 and large molecule radicals can react with the radicals in the glass surface to replace OH, and the hydrophobicity of the glass surface is improved accordingly.

BROMINATED FLAME RETARDANTS: WHY DO WE CARE?

EPA Science Inventory

Brominated flame retardants (BFRs) save lives and property by preventing the spread of fires or delaying the time of flashover, enhancing the time people have to escape. The worldwide production of BFRs exceeded 200,000 metric tons in 2003 placing them in the high production vol...

Airborne Observations of Water Vapor Deuterium Excess in the Mid-Latitude Lower Troposphere

NASA Astrophysics Data System (ADS)

Salmon, O. E.; Welp, L.; Shepson, P. B.; Stirm, B. H.

2017-12-01

Water vapor is responsible for over half of the natural atmospheric greenhouse effect. As global temperatures increase due to fossil fuel combustion, atmospheric water vapor concentrations are also expected to increase in positive feedback. Additionally, studies have shown that urban areas can influence humidity levels, and the frequency and intensity of precipitation events. It is thus important to understand anthropogenic modification of the hydrological cycle, particularly around urban areas, where over half of the world's population resides. Airborne measurements of water vapor isotopologues containing 2H and 18O were conducted to better understand processes influencing atmospheric moisture levels around urban areas. Airborne measurements were conducted around the Indianapolis and Washington, D.C.-Baltimore areas during afternoon hours in February and March 2016, using a Los Gatos Research Water Vapor Isotope Analyzer installed in Purdue University's experimental aircraft, the Airborne Laboratory for Atmospheric Research. The measurements of 2H and 18O allow for the calculation of deuterium excess (= δ2H - 8*δ18O), which provides information about non-equilibrium processes, such as kinetic effects, air parcel mixing, and transpiration. There are few studies that have reported observations of deuterium excess above the surface level ( 100 m). During the measurement campaign, vertical profiles were frequently conducted from 300 m above the ground to an altitude of approximately 1.5 km, effectively characterizing water vapor isotope profiles spanning the boundary layer and lower free troposphere. Measurements probed the transition from planetary boundary layer air to free troposphere air to provide high resolution deuterium excess information across this interface. Processes such as Rayleigh distillation, atmospheric mixing, and surface fluxes potentially impacting water vapor deuterium excess through the boundary layer and free troposphere with be discussed.

41 CFR 102-80.145 - What is meant by “flashover”?

Code of Federal Regulations, 2010 CFR

2010-07-01

...”? Flashover means fire conditions in a confined area where the upper gas layer temperature reaches 600 °C (1100 °F) and the heat flux at floor level exceeds 20 kW/m2 (1.8 Btu/ft2/sec). Reasonable Worst Case...

41 CFR 102-80.145 - What is meant by “flashover”?

Code of Federal Regulations, 2011 CFR

2011-01-01

...”? Flashover means fire conditions in a confined area where the upper gas layer temperature reaches 600 °C (1100 °F) and the heat flux at floor level exceeds 20 kW/m2 (1.8 Btu/ft2/sec). Reasonable Worst Case...

Deuterium sputtering of Li and Li-O films

NASA Astrophysics Data System (ADS)

Nelson, Andrew; Buzi, Luxherta; Kaita, Robert; Koel, Bruce

2017-10-01

Lithium wall coatings have been shown to enhance the operational plasma performance of many fusion devices, including NSTX and other tokamaks, by reducing the global wall recycling coefficient. However, pure lithium surfaces are extremely difficult to maintain in experimental fusion devices due to both inevitable oxidation and codeposition from sputtering of hot plasma facing components. Sputtering of thin lithium and lithium oxide films on a molybdenum target by energetic deuterium ion bombardment was studied in laboratory experiments conducted in a surface science apparatus. A Colutron ion source was used to produce a monoenergetic, mass-selected ion beam. Measurements were made under ultrahigh vacuum conditions as a function of surface temperature (90-520 K) using x-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES) and temperature programmed desorption (TPD). Results are compared with computer simulations conducted on a temperature-dependent data-calibrated (TRIM) model.

Hydrogen and deuterium transport and inventory parameters through W and W-alloys for fusion reactor applications

NASA Astrophysics Data System (ADS)

Benamati, G.; Serra, E.; Wu, C. H.

2000-12-01

The aim of this work is to measure the hydrogen/deuterium transport and inventory parameters in relevant structural and/or armour materials for the International Thermonuclear Experimental Reactor (ITER) divertor such as W and W-alloys. The W-alloys: W, W + 1% La 2O 3 and W + 5% Re have been investigated. The materials were supplied from the Metallwerk Plansee GmbH (Austria). Measurements were conducted using a time-dependent permeation method over the temperature range 673-873 K with hydrogen and deuterium pressures in the range 10-100 kPa (100-1000 mbar). The samples were also characterized using optical microscopy, SEM and energy dispersive spectroscopy (EDS) in order to investigate the composition, microstructure and morphology of the surfaces and cross-sections through the samples.

Extending the application of deuterium excess as a tracer in surface and groundwaters

NASA Astrophysics Data System (ADS)

Hurst, S.; Krishnamurthy, R. V.

2017-12-01

Stable isotopes of surface and ground waters provide invaluable information on the processes involved in their genesis. A starting point in these applications is the relationship between hydrogen (δ2H) and oxygen (δ18O), exemplified in the so-called Global Meteoric Water Line where δ2H=8δ18O+10 [1]. From this line Dansgaard [2] defined the parameter deuterium excess where d=δ2H-8δ18O. Generally, the d-excess value is fixed at the source, predominantly the equatorial oceans and retained. At an average humidity of about 85% the expected d-excess value is 10. Deviations indicate secondary changes in the air mass or a water body thus making d-excess a useful geophysical tracer. For instance, evaporation results in a higher d-excess in the vapor. Mixing of this water vapor with overhead air mass results in precipitation exhibiting d-excess values higher than Global Meteoric Water Line [3]. Alternatively, the fraction of liquid remaining will have low d-excess and in extreme cases negative d-excess. In this case a plot of d-excess-δ2H will give a straight line with a negative slope. This can be demonstrated from pan evaporation experiments [4]. Deviation from a perfect straight line on the d-excess-δ2H plot indicates a combination of mixing from various source waters and evaporation. This study will discuss various case studies from multiple environments applying this approach using d-excess. References [1] Craig, H. Standard for Reporting Concentrations of Deuterium and Oxygen-18 in Natural Waters. Science 133, 1833-1834 (1961). [2] Dansgaard, W. Stable isotopes in precipitation. Tellus A 16: 436-468 (1964). [3] Machavaram, M. &, Krishnamurthy, R.V. Earth surface evaporative process: a case study from the Great Lakes region of the United States based on deuterium excess in precipitation. Geochim. et Cosmochem. Acta 59, 4279-4283 (1995). [4] Simpson, H.J., Hamza, M.S., & White, J.W.C. Evaporative enrichment of deuterium and 18O in arid zone irrigation. IAEA, 241-256 (1987).

The interaction of molecular hydrogen with α-radiolytic oxidants on a (U,Pu)O2 surface

NASA Astrophysics Data System (ADS)

Bauhn, Lovisa; Hansson, Niklas; Ekberg, Christian; Fors, Patrik; Delville, Rémi; Spahiu, Kastriot

2018-07-01

In order to assess the impact of α-radiolysis of water on the oxidative dissolution of spent fuel, an un-irradiated, annealed MOX fuel pellet with high content of Pu (∼24 wt%), and a specific α-activity of 4.96 GBq/gMOX, was leached in carbonate-containing solutions of low ionic strength. The high Pu content in the pellet stabilizes the (U,Pu)O2(s) matrix towards oxidative dissolution, whereas the α-decays emitted from the surface are expected to produce ∼3.6 × 10-7 mol H2O2/day, contributing to the oxidative dissolution of the pellet. Two sets of leaching tests were conducted under different redox conditions: Ar gas atmosphere and deuterium gas atmosphere. A relatively slow increase of the U and Pu concentrations was observed in the Ar case, with U concentrations increasing from 1·10-6 M after 1 h to ∼7 × 10-5 M after 58 days. Leaching under an atmosphere starting at 1 MPa deuterium gas was undertaken in order to evaluate any effect of dissolved hydrogen on the radiolytic dissolution of the pellet, as well as to investigate any potential recombination of the α-radiolytic products with dissolved deuterium. For the latter purpose, isotopic analysis of the D/H content was carried out on solution samples taken during the leaching. Despite the continuous production of radiolytic oxidants, the concentrations of U and Pu remained quite constant at the level of ∼3 × 10-8 M during the first 30 days, i.e. as long as the deuterium pressure remained higher than 0.8 MPa. These data rule out any oxidative dissolution of the pellet during the first month. The un-irradiated MOX fuel does not contain metallic ε-particles, hence it is mainly the interaction of radiolytic oxidants and dissolved deuterium with the surface of the mixed actinide oxide that causes the neutralization of the oxidants. This conclusion is supported by the steadily increasing levels of HDO measured in the leachate samples.

Hydrogen ion-driven permeation in carbonaceous films

NASA Astrophysics Data System (ADS)

Anderl, R. A.; Holland, D. F.; Longhurst, G. R.

1989-04-01

This paper presents the results of investigations into the permeation properties of amorphous carbonaceous, a-C: H, films produced by plasmachemical deposition techniques. Carbonaceous films on iron substrates with thickness ranging from 60 nm to 110 nm were subjected to high fluence implantations with mass analyzed D +3 ions with energies ranging from 600 eV to 3000 eV and fluxes ranging from 5 × 10 14D/ cm2 s to 5 × 10 15D/ cm2 s, respectively. Deuterium re-emission upstream, deuterium permeation downstream and secondary ions sputtered from the implantation surface were measured as a function of implantation fluence for specimens at 420 K. The present studies indicate that the a-C : H film permeability is directly related to the time, hence the fluence, required to achieve isotopic replacement and saturation of the deuterium ion beam atoms stopped in the implant region. Once the deuterium saturation level is achieved in the layer, a significant fraction of the implanting ions can result in permeation. For the present experiment, this permeation factor was much higher than that for uncoated iron specimens subjected to similar beam conditions. Carbon sputter yields of 0.008-0.01 C/D were determined in this work for 1000-eV to 400-eV deuterium ions incident on a-C : H films.

Recent results on implantation and permeation into fusion reactor materials

NASA Astrophysics Data System (ADS)

Anderl, R. A.; Holland, D. F.; Longhurst, G. R.; Struttman, D. A.

This paper reports on implantation-driven permeation experiments that have been made for primary candidate alloy (PCA) and the ferritic steel HT-9 using deuterium ion beams from an accelerator. The results include measurements of the implantation flux and fluence dependence of the deuterium reemission and permeation for specimens heated to approximately 430(0)C. Simultaneous measurements of the ions sputtered from the specimen front surface with a secondary ion mass spectrometer provided some characterization of the surface condition throughout an experiment. For both materials, the permeation rate was lowered by the implantation process. However, the steady state permeation rate for HT-9 was found to be at least a factor of 5 greater than that for PCA.

CATALYTIC PROPERTIES OF SEMICONDUCTORS.

DTIC Science & Technology

SEMICONDUCTORS, CATALYSTS), (*CATALYSIS, REACTION KINETICS), (* SODIUM COMPOUNDS, TUNGSTATES), (*GALLIUM ALLOYS, ARSENIC ALLOYS), (*YTTERBIUM...COMPOUNDS, SILICIDES ), (*GERMANIUM, CATALYSIS), INTERNAL CONVERSION, EXCHANGE REACTIONS, HEAT OF ACTIVATION, THERMODYNAMICS, DEUTERIUM, POWDERS, SURFACES, HYDROGEN

Comparison of hydrogen and deuterium adsorption on Pd(100).

PubMed

Gladys, M J; Kambali, I; Karolewski, M A; Soon, A; Stampfl, C; O'Connor, D J

2010-01-14

Low energy ion recoil spectroscopy is a powerful technique for the determination of adsorbate position on metal surfaces. In this study, this technique is employed to compare the adsorption sites of hydrogen and deuterium on Pd(100) by detection of either H or D recoil ions produced by Ne(+) bombardment. Comparisons of experimental and Kalypso simulated azimuthal yield distributions show that, at room temperature, both hydrogen isotopes are adsorbed in the fourfold hollow site of Pd(100), however, at different heights above the surface (H-0.20 A and D-0.25 A). The adsorbates remain in the hollow site at all temperatures up to 383 K even though they move up to 0.40-0.45 A above the surface. Density functional theory calculations show a similar coverage dependent adsorption height for both H and D and confirm a real difference between the H and D adsorption heights based on zero point energies.

Method of using deuterium-cluster foils for an intense pulsed neutron source

DOEpatents

Miley, George H.; Yang, Xiaoling

2013-09-03

A method is provided for producing neutrons, comprising: providing a converter foil comprising deuterium clusters; focusing a laser on the foil with power and energy sufficient to cause deuteron ions to separate from the foil; and striking a surface of a target with the deuteron ions from the converter foil with energy sufficient to cause neutron production by a reaction selected from the group consisting of D-D fusion, D-T fusion, D-metal nuclear spallation, and p-metal. A further method is provided for assembling a plurality of target assemblies for a target injector to be used in the previously mentioned manner. A further method is provided for producing neutrons, comprising: splitting a laser beam into a first beam and a second beam; striking a first surface of a target with the first beam, and an opposite second surface of the target with the second beam with energy sufficient to cause neutron production.

Experimental investigations of castellated monoblock structures in TEXTOR

NASA Astrophysics Data System (ADS)

Litnovsky, A.; Philipps, V.; Wienhold, P.; Sergienko, G.; Emmoth, B.; Rubel, M.; Breuer, U.; Wessel, E.

2005-03-01

To insure the thermo-mechanical durability of ITER it is planned to manufacture the castellated armour of the divertor i.e. to split the armour into cells [W. Daener et al., Fusion Eng. Des. 61&62 (2002) 61]. This will cause an increase of the surface area and may lead to carbon deposition and tritium accumulation in the gaps in between cells. To investigate the processes of deposition and fuel accumulation in gaps, a castellated test-limiter was exposed to the SOL plasma of TEXTOR. The geometry of castellation used was the same as proposed for the vertical divertor target in ITER [W. Daener et al., Fusion Eng. Des. 61&62 (2002) 61]. After exposure the limiter was investigated with various surface diagnostic techniques. Deposited layers containing carbon, hydrogen, deuterium and boron were found both on top plasma-facing surfaces and in the gaps. The amount of deuterium in the gaps was at least 30% of that found on the top surfaces.

High translational energy release in H2 (D2) associative desorption from H (D) chemisorbed on C(0001).

PubMed

Baouche, S; Gamborg, G; Petrunin, V V; Luntz, A C; Baurichter, A; Hornekaer, L

2006-08-28

Highly energetic translational energy distributions are reported for hydrogen and deuterium molecules desorbing associatively from the atomic chemisorption states on highly oriented pyrolytic graphite (HOPG). Laser assisted associative desorption is used to measure the time of flight of molecules desorbing from a hydrogen (deuterium) saturated HOPG surface produced by atomic exposure from a thermal atom source at around 2100 K. The translational energy distributions normal to the surface are very broad, from approximately 0.5 to approximately 3 eV, with a peak at approximately 1.3 eV. The highest translational energy measured is close to the theoretically predicted barrier height. The angular distribution of the desorbing molecules is sharply peaked along the surface normal and is consistent with thermal broadening contributing to energy release parallel to the surface. All results are in qualitative agreement with recent density functional theory calculations suggesting a lowest energy para-type dimer recombination path.

Results from the irradiation of stainless steel and copper by 23 MeV γ-quanta in the atmosphere of molecular deuterium at a pressure of 2 kbar

NASA Astrophysics Data System (ADS)

Didyk, A. Yu.; Wisniewski, R.

2014-05-01

Metal samples were arranged inside a "finger-type" high-pressure chamber (DHPC-FT) filled by deuterium. They were two aluminum rods, a copper rod, two specimens of homogeneous YMn2 alloy, and a stainless steel wire. The pressure of molecular deuterium in DHPC-FT was about 2 kbar. The samples were irradiated by braking γ-quanta at a threshold energy of 23 MeV. All the samples were studied using scanning electron microscopy (SEM) and X-ray (roentgen) microelement probe analysis (RMPA). Considerable changes in the surface structure and elemental composition were found for the samples of copper, aluminum, YMn2 alloy, and stainless steel. Unusual results were analyzed in detail and compared with the earlier data.

Preheating temperature effect on tritium retention in VPS-W

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sato, M.; Uchimura, H.; Toda, K.

The W coating by Vacuum Plasma Spraying (VPS) technology is thought to be reasonable for most plasma facing components in future fusion reactors. In this paper the deuterium retention behavior for the Vacuum Plasma Spraying (VPS) tungsten (W) coating has been studied to demonstrate the tritium retention as a function of heating temperature. It has been found that two major deuterium desorption stages were observed at the temperature regions of 400 - 700 K (Stage 1) and 900 - 1100 K (Stage 2), considering that Stage 1 has been linked to the desorption of deuterium trapped by near surface andmore » intrinsic defects, and Stage 2 has been related to the desorption of deuterium bound to impurities as C-D bonds. By heating the sample above 673 K, the major peak of C-1s shifted from C-O bond to C-C bond, where the retention of deuterium as Stage 2 has increased. Therefore it indicates that the hydrogen isotope retention was controlled by the amount of C-C bond in VPS, most of which was contaminated during the VPS coating process. The comparison of several samples (VPS-W with shading, VPS-W without shading and Polycrystalline W (PCW)) shows that the carbon impurity has a large affinity with deuterium and makes stable trapping states compared to that with intrinsic defects and grain boundaries. However, most of them was reduced by heating at 1173 K. Therefore, heating treatment is quite important to get rid of carbon impurities and refrain higher tritium retention in VPS. (authors)« less

Stabilization of sawteeth with third harmonic deuterium ICRF-accelerated beam in JET plasmas

NASA Astrophysics Data System (ADS)

Girardo, Jean-Baptiste; Sharapov, Sergei; Boom, Jurrian; Dumont, Rémi; Eriksson, Jacob; Fitzgerald, Michael; Garbet, Xavier; Hawkes, Nick; Kiptily, Vasily; Lupelli, Ivan; Mantsinen, Mervi; Sarazin, Yanick; Schneider, Mireille

2016-01-01

Sawtooth stabilisation by fast ions is investigated in deuterium (D) and D-helium 3 (He3) plasmas of JET heated by deuterium Neutral Beam Injection combined in synergy with Ion Cyclotron Resonance Heating (ICRH) applied on-axis at 3rd beam cyclotron harmonic. A very significant increase in the sawtooth period is observed, caused by the ICRH-acceleration of the beam ions born at 100 keV to the MeV energy range. Four representative sawteeth from four different discharges are compared with Porcelli's model. In two discharges, the sawtooth crash appears to be triggered by core-localized Toroidal Alfvén Eigenmodes inside the q = 1 surface (also called "tornado" modes) which expel the fast ions from within the q = 1 surface, over time scales comparable with the sawtooth period. Two other discharges did not exhibit fast ion-driven instabilities in the plasma core, and no degradation of fast ion confinement was found in both modelling and direct measurements of fast ion profile with the neutron camera. The developed sawtooth scenario without fast ion-driven instabilities in the plasma core is of high interest for the burning plasmas. Possible causes of the sawtooth crashes on JET are discussed.

A neutron diagnostic for high current deuterium beams.

PubMed

Rebai, M; Cavenago, M; Croci, G; Dalla Palma, M; Gervasini, G; Ghezzi, F; Grosso, G; Murtas, F; Pasqualotto, R; Cippo, E Perelli; Tardocchi, M; Tollin, M; Gorini, G

2012-02-01

A neutron diagnostic for high current deuterium beams is proposed for installation on the spectral shear interferometry for direct electric field reconstruction (SPIDER, Source for Production of Ion of Deuterium Extracted from RF plasma) test beam facility. The proposed detection system is called Close-contact Neutron Emission Surface Mapping (CNESM). The diagnostic aims at providing the map of the neutron emission on the beam dump surface by placing a detector in close contact, right behind the dump. CNESM uses gas electron multiplier detectors equipped with a cathode that also serves as neutron-proton converter foil. The cathode is made of a thin polythene film and an aluminium film; it is designed for detection of neutrons of energy >2.2 MeV with an incidence angle < 45°. CNESM was designed on the basis of simulations of the different steps from the deuteron beam interaction with the beam dump to the neutron detection in the nGEM. Neutron scattering was simulated with the MCNPX code. CNESM on SPIDER is a first step towards the application of this diagnostic technique to the MITICA beam test facility, where it will be used to resolve the horizontal profile of the beam intensity.

A neutron diagnostic for high current deuterium beams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rebai, M.; Perelli Cippo, E.; Cavenago, M.

2012-02-15

A neutron diagnostic for high current deuterium beams is proposed for installation on the spectral shear interferometry for direct electric field reconstruction (SPIDER, Source for Production of Ion of Deuterium Extracted from RF plasma) test beam facility. The proposed detection system is called Close-contact Neutron Emission Surface Mapping (CNESM). The diagnostic aims at providing the map of the neutron emission on the beam dump surface by placing a detector in close contact, right behind the dump. CNESM uses gas electron multiplier detectors equipped with a cathode that also serves as neutron-proton converter foil. The cathode is made of a thinmore » polythene film and an aluminium film; it is designed for detection of neutrons of energy >2.2 MeV with an incidence angle < 45 deg. CNESM was designed on the basis of simulations of the different steps from the deuteron beam interaction with the beam dump to the neutron detection in the nGEM. Neutron scattering was simulated with the MCNPX code. CNESM on SPIDER is a first step towards the application of this diagnostic technique to the MITICA beam test facility, where it will be used to resolve the horizontal profile of the beam intensity.« less

Influence of the Al wire placed in the anode axis on the transformation of the deuterium plasma column in the plasma focus discharge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kubes, P.; Cikhardtova, B.; Cikhardt, J.

In this paper, we describe the influence of an Al wire of 270 μm in diameter placed along the anode axis on the transformation of the deuterium pinch column in a megaampere (MA) plasma focus device. The evolution of the pinched column and of the wire corona was investigated by means of the multiframe interferometry, neutron and X-ray diagnostics. The wire corona did not influence considerably on the evolution of dense plasma structures and neutron production, but it increased the plasma density and consequently, the currents around its surface. The distribution of the closed internal currents (ranging hundreds of kA) andmore » associated magnetic fields amounting to 5 T were also estimated in the dense plasma column and in plasmoidal structures at the near-equilibrium state. The description is based on the balance of the plasma pressure and the pressure of the internal poloidal and toroidal current components compressed by the external pinched column. The dominant number of fusion deuterium-deuterium (D-D) neutrons is produced during the evolution of instabilities, when the uninterrupted wire corona (containing deuterium) connects the dense structures of the pinch, and it did not allow the formation of a constriction of the sub-millimeter diameter.« less

Detection of Deuterium in Icy Surfaces and the D/H Ratio of Icy Objects

NASA Astrophysics Data System (ADS)

Clark, Roger Nelson; Brown, Robert H.; Swayze, Gregg A.; Cruikshank, Dale P.

2017-10-01

Water ice in crystalline or amorphous form is orientationally disordered, which results in very broad absorptions. Deuterium in trace amounts goes into an ordered position, so is not broadened like H2O absorptions. The D-O stretch is located at 4.13 microns with a width of 0.027 micron. Laboratory spectral measurements on natural H2O and deuterium doped ice show the absorption is slightly asymmetric and in reflectance the band shifts from 4.132 to 4.137 microns as abundance decreases. We derive a preliminary absorption coefficient of ~ 80,000 cm^-1 for the D-O stretch compared to about 560 cm^-1 in H2O ice at 4.13 microns, enabling the detection of deuterium at levels less than Vienna Standard Mean Ocean Water (VSMOW), depending on S/N. How accurate the D/H ratios can be derived will require additional lab work and radiative transfer modeling to simultaneously derive the grain size distribution, the abundance of any contaminants, and deuterium abundance. To first order, the grain size distribution can be compensated by computing the D-O stretch band depth to 2-micron H2O ice band depth ratio, which we call Dratio. Colorado fresh water (~80% of VSMOW) has a Dratio of 0.036, at a D/H = 0.0005, the Dratio = 0.15, and at a D/H = 0.0025, the Dratio = 0.42. The VSMOW Dratio is ~ 0.045.We have used VIMS data from the Cassini spacecraft to compute large spectral averages to detect the deuterium in the rings and on the icy satellite surfaces. A B-ring, 21,882 pixel average, at 640 ms/pixel, or 3.89 hours of integration time, shows a 3.5% O-D stretch band depth and a Dratio = 0.045, indicating deuterium abundance equal to VSMOW. Rhea, using 1.89 hours of integration time shows Dratio = 0.052, or slightly higher than VSMOW. Phoebe has an unusually deep O-D stretch band of 1.85% considering the high abundance of dark material suppressing the ice absorptions. We measure a Dratio = 0.11, an enhancement of ~2.4 over VSMOW, but detailed radiative transfer modeling is needed to derive a more accurate ratio. The enhancement is consistent with previous studies that suggest Phoebe's origin might be external to the Saturn system. More satellites and radiative transfer modeling results will be shown at the meeting.

Multiple Paths of Deuterium Fractionation in Protoplanetary Disks

NASA Astrophysics Data System (ADS)

Aikawa, Yuri; Furuya, Kenji; Hincelin, Ugo; Herbst, Eric

2018-03-01

We investigate deuterium chemistry coupled with the nuclear spin-state chemistry of H2 and {{{H}}}3+ in protoplanetary disks. Multiple paths of deuterium fractionation are found; exchange reactions with D atoms, such as HCO+ + D, are effective in addition to those with HD. In a disk model with grain sizes appropriate for dark clouds, the freeze-out of molecules is severe in the outer midplane, while the disk surface is shielded from UV radiation. Gaseous molecules, including DCO+, thus become abundant at the disk surface, which tends to make their column density distribution relatively flat. If the dust grains have grown to millimeter size, the freeze-out rate of neutral species is reduced and the abundances of gaseous molecules, including DCO+ and N2D+, are enhanced in the cold midplane. Turbulent diffusion transports D atoms and radicals at the disk surface to the midplane, and stable ice species in the midplane to the disk surface. The effects of turbulence on chemistry are thus multifold; while DCO+ and N2D+ abundances increase or decrease depending on the regions, HCN and DCN in the gas and ice are greatly reduced at the innermost radii, compared to the model without turbulence. When cosmic rays penetrate the disk, the ortho-to-para ratio (OPR) of H2 is found to be thermal in the disk, except in the cold (≲10 K) midplane. We also analyze the OPR of {{{H}}}3+ and H2D+, as well as the main reactions of H2D+, DCO+, and N2D+, in order to analytically derive their abundances in the cold midplane.

Neutron interrogation systems using pyroelectric crystals and methods of preparation thereof

DOEpatents

Tang, Vincent; Meyer, Glenn A.; Falabella, Steven; Guethlein, Gary; Rusnak, Brian; Sampayan, Stephen; Spadaccini, Christopher M.; Wang, Li-Fang; Harris, John; Morse, Jeff

2017-08-01

According to one embodiment, an apparatus includes a pyroelectric crystal, a deuterated or tritiated target, an ion source, and a common support coupled to the pyroelectric crystal, the deuterated or tritiated target, and the ion source. In another embodiment, a method includes producing a voltage of negative polarity on a surface of a deuterated or tritiated target in response to a temperature change of a pyroelectric crystal, pulsing a deuterium ion source to produce a deuterium ion beam, accelerating the deuterium ion beam to the deuterated or tritiated target to produce a neutron beam, and directing the ion beam onto the deuterated or tritiated target to make neutrons using a voltage of the pyroelectric crystal and/or an HGI surrounding the pyroelectric crystal. The directionality of the neutron beam is controlled by changing the accelerating voltage of the system. Other apparatuses and methods are presented as well.

A ceramic radial insulation structure for a relativistic electron beam vacuum diode.

PubMed

Xun, Tao; Yang, Hanwu; Zhang, Jiande; Liu, Zhenxiang; Wang, Yong; Zhao, Yansong

2008-06-01

For one kind of a high current diode composed of a small disk-type alumina ceramic insulator water/vacuum interface, the insulation structure was designed and experimentally investigated. According to the theories of vacuum flashover and the rules for radial insulators, a "cone-column" anode outline and the cathode shielding rings were adopted. The electrostatic field along the insulator surface was obtained by finite element analysis simulating. By adjusting the outline of the anode and reshaping the shielding rings, the electric fields were well distributed and the field around the cathode triple junction was effectively controlled. Area weighted statistical method was applied to estimate the surface breakdown field. In addition, the operating process of an accelerator based on a spiral pulse forming line (PFL) was simulated through the PSPICE software to get the waveform of charging and diode voltage. The high voltage test was carried out on a water dielectric spiral PFL accelerator with long pulse duration, and results show that the diode can work stably in 420 kV, 200 ns conditions. The experimental results agree with the theoretical and simulated results.

41 CFR 102-80.115 - Is there more than one option for establishing that an equivalent level of safety exists?

Code of Federal Regulations, 2013 CFR

2013-07-01

..., complete sprinkler protection can be expected to prevent flashover in the room of fire origin, limit fire... the times required for egress. If a combination of fire protection systems provides a margin of safety... Contracts and Property Management Federal Property Management Regulations System (Continued) FEDERAL...

41 CFR 102-80.115 - Is there more than one option for establishing that an equivalent level of safety exists?

Code of Federal Regulations, 2012 CFR

2012-01-01

..., complete sprinkler protection can be expected to prevent flashover in the room of fire origin, limit fire... the times required for egress. If a combination of fire protection systems provides a margin of safety... Contracts and Property Management Federal Property Management Regulations System (Continued) FEDERAL...

41 CFR 102-80.115 - Is there more than one option for establishing that an equivalent level of safety exists?

Code of Federal Regulations, 2014 CFR

2014-01-01

..., complete sprinkler protection can be expected to prevent flashover in the room of fire origin, limit fire... the times required for egress. If a combination of fire protection systems provides a margin of safety... Contracts and Property Management Federal Property Management Regulations System (Continued) FEDERAL...

41 CFR 102-80.115 - Is there more than one option for establishing that an equivalent level of safety exists?

Code of Federal Regulations, 2011 CFR

2011-01-01

..., complete sprinkler protection can be expected to prevent flashover in the room of fire origin, limit fire... the times required for egress. If a combination of fire protection systems provides a margin of safety... Contracts and Property Management Federal Property Management Regulations System (Continued) FEDERAL...

Catalytic dehydration of biomass derived 1-propanol to propene over M-ZSM-5 (M = H, V, Cu, or Zn)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lepore, Andrew W.; Li, Zhenglong; Davison, Brian H.

Here, the impetus to explore biomass derived chemicals arises from a desire to enable renewable and sustainable commodity chemicals. To this end, we report catalytic production of propene, a building-block molecule, from 1-propanol. We found that zeolite catalysts are quite versatile and can produce propene at or below 230 C with high selectivity. Increasing the reaction temperature above 230 C shifted product selectivity towards C4+ hydrocarbons. Cu-ZSM-5 was found to exhibit a broader temperature window for high propene selectivity and could function at higher 1-propanol space velocities than H-ZSM-5. A series of experiments with 1-propan(ol-D) showed deuterium incorporation in themore » hydrocarbon product stream including propene suggesting that hydrocarbon pool type pathway might be operational concurrent with dehydration to produce C4+ hydrocarbons. Diffuse reflectance infra-red spectroscopy of 1-propanol and 1-propan(ol-D) over Cu-ZSM-5 in combination with deuterium labeling experiments suggest that deuterium incorporation occurs in two steps. Incorporation of deuterium occurs post dehydration via exchange with the partially deuterated catalyst surface.« less

Catalytic dehydration of biomass derived 1-propanol to propene over M-ZSM-5 (M = H, V, Cu, or Zn)

DOE PAGES

Lepore, Andrew W.; Li, Zhenglong; Davison, Brian H.; ...

2017-04-03

Here, the impetus to explore biomass derived chemicals arises from a desire to enable renewable and sustainable commodity chemicals. To this end, we report catalytic production of propene, a building-block molecule, from 1-propanol. We found that zeolite catalysts are quite versatile and can produce propene at or below 230 C with high selectivity. Increasing the reaction temperature above 230 C shifted product selectivity towards C4+ hydrocarbons. Cu-ZSM-5 was found to exhibit a broader temperature window for high propene selectivity and could function at higher 1-propanol space velocities than H-ZSM-5. A series of experiments with 1-propan(ol-D) showed deuterium incorporation in themore » hydrocarbon product stream including propene suggesting that hydrocarbon pool type pathway might be operational concurrent with dehydration to produce C4+ hydrocarbons. Diffuse reflectance infra-red spectroscopy of 1-propanol and 1-propan(ol-D) over Cu-ZSM-5 in combination with deuterium labeling experiments suggest that deuterium incorporation occurs in two steps. Incorporation of deuterium occurs post dehydration via exchange with the partially deuterated catalyst surface.« less

Monte Carlo simulation of explosive detection system based on a Deuterium-Deuterium (D-D) neutron generator.

PubMed

Bergaoui, K; Reguigui, N; Gary, C K; Brown, C; Cremer, J T; Vainionpaa, J H; Piestrup, M A

2014-12-01

An explosive detection system based on a Deuterium-Deuterium (D-D) neutron generator has been simulated using the Monte Carlo N-Particle Transport Code (MCNP5). Nuclear-based explosive detection methods can detect explosives by identifying their elemental components, especially nitrogen. Thermal neutron capture reactions have been used for detecting prompt gamma emission (10.82MeV) following radiative neutron capture by (14)N nuclei. The explosive detection system was built based on a fully high-voltage-shielded, axial D-D neutron generator with a radio frequency (RF) driven ion source and nominal yield of about 10(10) fast neutrons per second (E=2.5MeV). Polyethylene and paraffin were used as moderators with borated polyethylene and lead as neutron and gamma ray shielding, respectively. The shape and the thickness of the moderators and shields are optimized to produce the highest thermal neutron flux at the position of the explosive and the minimum total dose at the outer surfaces of the explosive detection system walls. In addition, simulation of the response functions of NaI, BGO, and LaBr3-based γ-ray detectors to different explosives is described. Copyright © 2014 Elsevier Ltd. All rights reserved.

ALCHEMIC: Advanced time-dependent chemical kinetics

NASA Astrophysics Data System (ADS)

Semenov, Dmitry A.

2017-08-01

ALCHEMIC solves chemical kinetics problems, including gas-grain interactions, surface reactions, deuterium fractionization, and transport phenomena and can model the time-dependent chemical evolution of molecular clouds, hot cores, corinos, and protoplanetary disks.

Ignition of deuterium-trtium fuel targets

DOEpatents

Musinski, Donald L.; Mruzek, Michael T.

1991-01-01

A method of igniting a deuterium-tritium ICF fuel target to obtain fuel burn in which the fuel target initially includes a hollow spherical shell having a frozen layer of DT material at substantially uniform thickness and cryogenic temperature around the interior surface of the shell. The target is permitted to free-fall through a target chamber having walls heated by successive target ignitions, so that the target is uniformly heated during free-fall to at least partially melt the frozen fuel layer and form a liquid single-phase layer or a mixed liquid/solid bi-phase layer of substantially uniform thickness around the interior shell surface. The falling target is then illuminated from exteriorly of the chamber while the fuel layer is at substantially uniformly single or bi-phase so as to ignite the fuel layer and release energy therefrom.

Ignition of deuterium-tritium fuel targets

DOEpatents

Musinski, D.L.; Mruzek, M.T.

1991-08-27

Disclosed is a method of igniting a deuterium-tritium ICF fuel target to obtain fuel burn in which the fuel target initially includes a hollow spherical shell having a frozen layer of DT material at substantially uniform thickness and cryogenic temperature around the interior surface of the shell. The target is permitted to free-fall through a target chamber having walls heated by successive target ignitions, so that the target is uniformly heated during free-fall to at least partially melt the frozen fuel layer and form a liquid single-phase layer or a mixed liquid/solid bi-phase layer of substantially uniform thickness around the interior shell surface. The falling target is then illuminated from exteriorly of the chamber while the fuel layer is at substantially uniformly single or bi-phase so as to ignite the fuel layer and release energy therefrom. 5 figures.

Neutron tubes

DOEpatents

Leung, Ka-Ngo [Hercules, CA; Lou, Tak Pui [Berkeley, CA; Reijonen, Jani [Oakland, CA

2008-03-11

A neutron tube or generator is based on a RF driven plasma ion source having a quartz or other chamber surrounded by an external RF antenna. A deuterium or mixed deuterium/tritium (or even just a tritium) plasma is generated in the chamber and D or D/T (or T) ions are extracted from the plasma. A neutron generating target is positioned so that the ion beam is incident thereon and loads the target. Incident ions cause D-D or D-T (or T-T) reactions which generate neutrons. Various embodiments differ primarily in size of the chamber and position and shape of the neutron generating target. Some neutron generators are small enough for implantation in the body. The target may be at the end of a catheter-like drift tube. The target may have a tapered or conical surface to increase target surface area.

Stabilization of sawteeth with third harmonic deuterium ICRF-accelerated beam in JET plasmas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Girardo, Jean-Baptiste; CEA, IRFM, F-13108 Saint-Paul-lez-Durance; Sharapov, Sergei

Sawtooth stabilisation by fast ions is investigated in deuterium (D) and D-helium 3 (He3) plasmas of JET heated by deuterium Neutral Beam Injection combined in synergy with Ion Cyclotron Resonance Heating (ICRH) applied on-axis at 3rd beam cyclotron harmonic. A very significant increase in the sawtooth period is observed, caused by the ICRH-acceleration of the beam ions born at 100 keV to the MeV energy range. Four representative sawteeth from four different discharges are compared with Porcelli's model. In two discharges, the sawtooth crash appears to be triggered by core-localized Toroidal Alfvén Eigenmodes inside the q = 1 surface (also called “tornado” modes)more » which expel the fast ions from within the q = 1 surface, over time scales comparable with the sawtooth period. Two other discharges did not exhibit fast ion-driven instabilities in the plasma core, and no degradation of fast ion confinement was found in both modelling and direct measurements of fast ion profile with the neutron camera. The developed sawtooth scenario without fast ion-driven instabilities in the plasma core is of high interest for the burning plasmas. Possible causes of the sawtooth crashes on JET are discussed.« less

Fire endurance research at the Forest Products Laboratory

Treesearch

R. H. White

1990-01-01

Fire endurance research activities and facilities at the FPL concern the ability of a wood member or assembly to withstand the effects of fire while acting as a fire barrier and supporting a load. Fire endurance is generally concerned with the post-flashover portion of the fire. The importance of fire endurance in fire safety is reflected in building code requirements...

Combined and isolated effects of pCO2 and soil water content on carbon isotope discrimination during C3 photosynthesis

NASA Astrophysics Data System (ADS)

Salmon, O. E.; Welp, L.; Shepson, P. B.; Stirm, B. H.

2016-12-01

Water vapor is responsible for over half of the natural atmospheric greenhouse effect. As global temperatures increase due to fossil fuel combustion, atmospheric water vapor concentrations are also expected to increase in positive feedback. Additionally, studies have shown that urban areas can influence humidity levels, and the frequency and intensity of precipitation events. It is thus important to understand anthropogenic modification of the hydrological cycle, particularly around urban areas, where over half of the world's population resides. Airborne measurements of water vapor isotopologues containing 2H and 18O were conducted to better understand processes influencing atmospheric moisture levels around urban areas. Airborne measurements were conducted around the Indianapolis and Washington, D.C.-Baltimore areas during afternoon hours in February and March 2016, using a Los Gatos Research Water Vapor Isotope Analyzer installed in Purdue University's experimental aircraft, the Airborne Laboratory for Atmospheric Research. The measurements of 2H and 18O allow for the calculation of deuterium excess (= δ2H - 8*δ18O), which provides information about non-equilibrium processes, such as kinetic effects, air parcel mixing, and transpiration. There are few studies that have reported observations of deuterium excess above the surface level ( 100 m). During the measurement campaign, vertical profiles were frequently conducted from 300 m above the ground to an altitude of approximately 1.5 km, effectively characterizing water vapor isotope profiles spanning the boundary layer and lower free troposphere. Measurements probed the transition from planetary boundary layer air to free troposphere air to provide high resolution deuterium excess information across this interface. Processes such as Rayleigh distillation, atmospheric mixing, and surface fluxes potentially impacting water vapor deuterium excess through the boundary layer and free troposphere with be discussed.

Properties of the surface snow in Princess Elizabeth Land, East Antarctica - climate and non-climate dependent variability of the surface mass balance and stable water isotopic composition

NASA Astrophysics Data System (ADS)

Vladimirova, D.; Ekaykin, A.; Lipenkov, V.; Popov, S. V.; Petit, J. R.; Masson-Delmotte, V.

2017-12-01

Glaciological and meteorological observations conducted during the past four decades in Princess Elizabeth Land, East Antarctica, are compiled. The database is used to investigate spatial patterns of surface snow isotopic composition and surface mass balance, including detailed information near subglacial lake Vostok. We show diverse relationships between snow isotopic composition and surface temperature. In the most inland part (elevation 3200-3400 m a.s.l.), surface snow isotopic composition varies independently from surface temperature, and is closely related to the distance to the open water source (with a slope of 0.98±0.17 ‰ per 100 km). Surface mass balance values are higher along the ice sheet slope, and relatively evenly distributed inland. The minimum values of snow isotopic composition and surface mass balance are identified in an area XX km southwestward from Vostok station. The spatial distribution of deuterium excess delineates regions influenced by the Indian Ocean and Pacific Ocean air masses, with Vostok area being situated close to their boundary. Anomalously high deuterium excess values are observed near Dome A, suggesting high kinetic fractionation for its moisture source, or specifically high post-deposition artifacts. The dataset is available for further studies such as the assessment of skills of general circulation or regional atmospheric models, and the search for the oldest ice.

Tunneling in hydrogen and deuterium atom addition to CO at low temperatures

NASA Astrophysics Data System (ADS)

Andersson, Stefan; Goumans, T. P. M.; Arnaldsson, Andri

2011-09-01

The hydrogen and deuterium atom addition reactions of CO to form HCO and DCO are addressed by Harmonic Quantum Transition State Theory calculations. Special attention is paid to the reactions at very low temperatures (5-20 K) where it is found that quantum tunneling leads to substantial rates of reaction. This supports experiments in the solid phase, which conclude that these reactions are driven by tunneling at low temperatures. The calculated kinetic isotope effect of kD/ kH = 1/250 is found to be lower than the experimentally deduced value of 0.08 for the surface reaction. Possible reasons for this discrepancy are discussed.

Fast deuterium fractionation in magnetized and turbulent filaments

NASA Astrophysics Data System (ADS)

Körtgen, B.; Bovino, S.; Schleicher, D. R. G.; Stutz, A.; Banerjee, R.; Giannetti, A.; Leurini, S.

2018-04-01

Deuterium fractionation is considered as an important process to infer the chemical ages of prestellar cores in filaments. We present here the first magneto-hydrodynamical simulations including a chemical network to study deuterium fractionation in magnetized and turbulent filaments, with a line-mass of Mlin = 42 M⊙ pc-1 within a radius of R = 0.1 pc, and their substructures. The filaments typically show widespread deuterium fractionation with average values ≳ 0.01. For individual cores of similar age, we observe the deuteration fraction to increase with time, but also to be independent of their average properties such as density, virial or mass-to-magnetic flux ratio. We further find a correlation of the deuteration fraction with core mass, average H2 density and virial parameter only at late evolutionary stages of the filament and attribute this to the lifetime of the individual cores. Specifically, chemically old cores reveal higher deuteration fractions. Within the radial profiles of selected cores, we notice differences in the structure of the deuteration fraction or surface density, which we can attribute to their different turbulent properties. High deuteration fractions of the order 0.01 - 0.1 may be reached within approximately 200 kyrs, corresponding to two free-fall times, as defined for cylindrical systems, of the filaments.

Fast deuterium fractionation in magnetized and turbulent filaments

NASA Astrophysics Data System (ADS)

Körtgen, B.; Bovino, S.; Schleicher, D. R. G.; Stutz, A.; Banerjee, R.; Giannetti, A.; Leurini, S.

2018-07-01

Deuterium fractionation is considered as an important process to infer the chemical ages of prestellar cores in filaments. We present here the first magnetohydrodynamical simulations including a chemical network to study deuterium fractionation in magnetized and turbulent filaments, with a line-mass of Mlin = 42 M⊙ pc-1 within a radius of R= 0.1 pc, and their sub-structures. The filaments typically show widespread deuterium fractionation with average values ≳0.01. For individual cores of similar age, we observe the deuteration fraction to increase with time, but also to be independent of their average properties such as density, virial, or mass-to-magnetic flux ratio. We further find a correlation of the deuteration fraction with core mass, average H2 density, and virial parameter only at late evolutionary stages of the filament and attribute this to the lifetime of the individual cores. Specifically, chemically old cores reveal higher deuteration fractions. Within the radial profiles of selected cores, we notice differences in the structure of the deuteration fraction or surface density, which we can attribute to their different turbulent properties. High deuteration fractions of the order of 0.01-0.1 may be reached within approximately 200 kyr, corresponding to two free-fall times, as defined for cylindrical systems, of the filaments.

Significant Quantum Effects in Hydrogen Activation

DOE PAGES

Kyriakou, Georgios; Davidson, Erlend R. M.; Peng, Guowen; ...

2014-03-31

Dissociation of molecular hydrogen is an important step in a wide variety of chemical, biological, and physical processes. Due to the light mass of hydrogen, it is recognized that quantum effects are often important to its reactivity. However, understanding how quantum effects impact the reactivity of hydrogen is still in its infancy. Here, we examine this issue using a well-defined Pd/Cu(111) alloy that allows the activation of hydrogen and deuterium molecules to be examined at individual Pd atom surface sites over a wide range of temperatures. Experiments comparing the uptake of hydrogen and deuterium as a function of temperature revealmore » completely different behavior of the two species. The rate of hydrogen activation increases at lower sample temperature, whereas deuterium activation slows as the temperature is lowered. Density functional theory simulations in which quantum nuclear effects are accounted for reveal that tunneling through the dissociation barrier is prevalent for H 2 up to ~190 K and for D 2 up to ~140 K. Kinetic Monte Carlo simulations indicate that the effective barrier to H 2 dissociation is so low that hydrogen uptake on the surface is limited merely by thermodynamics, whereas the D 2 dissociation process is controlled by kinetics. These data illustrate the complexity and inherent quantum nature of this ubiquitous and seemingly simple chemical process. Here, examining these effects in other systems with a similar range of approaches may uncover temperature regimes where quantum effects can be harnessed, yielding greater control of bond-breaking processes at surfaces and uncovering useful chemistries such as selective bond activation or isotope separation.« less

Surface modification and deuterium retention in reduced-activation steels under low-energy deuterium plasma exposure. Part I: undamaged steels

NASA Astrophysics Data System (ADS)

Ogorodnikova, O. V.; Zhou, Z.; Sugiyama, K.; Balden, M.; Gasparyan, Yu.; Efimov, V.

2017-03-01

In this paper, reduced-activation ferritic/martensitic (RAFM) steels including Eurofer (9Cr) and oxide dispersion strengthening (ODS) steels by the addition of Y2O3 particles with different amounts of Cr, namely, (9-16)Cr were exposed to low energy deuterium (D) plasma (~20-200 eV per D) up to a fluence of 2.9  ×  1025 D m-2 in the temperature range from 290 K to 700 K. The depth profile of D in steels was measured up to 8 µm depth by nuclear reaction analysis (NRA) and the total retained amount of D in those materials was determined by thermal desorption spectroscopy (TDS). It was found that the D retention in ODS steels is higher compared to Eurofer due to the much higher density of fine dispersoids and finer grain size. This work shows that in addition to the sintering temperature and time, the type, size and concentration of the doping particles have an enormous effect on the increase in the D retention. The D retention in undamaged ODS steels strongly depends on the Cr content: ODS with 12Cr has a minimum and the D retention in the case of ODS with (14-16)Cr is higher compared to (9-12)Cr. The replacing of Ti by Al in ODS-14Cr steels reduces the D retention. The formation of nano-structure surface roughness enriched in W or Ta due to combination of preferential sputtering of light elements and radiation-induced segregation was observed at incident D ion energy of 200 eV for both Eurofer and ODS steels. Both the surface roughness and the eroded layer enhance with increasing the temperature. The surface modifications result in a reduction of the D retention near the surface due to increasing the desorption flux and can reduce the overall D retention.

Deuterium enrichment by selective photoinduced dissociation of a multihalogenated organic compound

DOEpatents

Marling, John B.; Herman, Irving P.

1981-01-01

A method for deuterium enrichment by photoinduced dissociation which uses as the deuterium source a multihalogenated organic compound selected from the group consisting of a dihalomethane, a trihalomethane, a 1,2-dihaloethene, a trihaloethene, a tetrahaloethane and a pentahaloethane. The multihalogenated organic compound is subjected to intense infrared radiation at a preselected wavelength to selectively excite and thereby induce dissociation of substantially only those molecules containing deuterium to provide a deuterium enriched dissociation product. The deuterium enriched product may be combusted with oxygen to provide deuterium enriched water. The deuterium depleted undissociated molecules may be redeuterated by treatment with a deuterium source such as water.

Deuterium transport in Cu, CuCrZr, and Cu/Be

NASA Astrophysics Data System (ADS)

Anderl, R. A.; Hankins, M. R.; Longhurst, G. R.; Pawelko, R. J.

This paper presents the results of deuterium implantation/permeation experiments and TMAP4 simulations for a CuCrZr alloy, for OFHC-Cu and for a Cu/Be bi-layered structure at temperatures from 700 to 800 K. Experiments used a mass-analyzed, 3-keV D 3+ ion beam with particle flux densities of 5 × 10 19 to 7 × 10 19 D/m 2 s. Effective diffusivities and surface molecular recombination coefficients were derived giving Arrhenius pre-exponentials and activation energies for each material: CuCrZr alloy, (2.0 × 10 -2 m 2/s, 1.2 eV) for diffusivity and (2.9 × x10 -14 m 4/s, 1.92 eV) for surface molecular recombination coefficients; OFHC Cu, (2.1 × 10 -6 m 2/s, 0.52 eV) for diffusivity and (9.1 × 10 -18 m 4/s, 0.99 eV) for surface molecular recombination coefficients. TMAP4 simulation of permeation data measured for a Cu/Be bi-layer sample was achieved using a four-layer structure (Cu/BeO interface/Be/BeO back surface) and recommended values for diffusivity and solubility in Be, BeO and Cu.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, T.Q.; Buczkowski, A.; Radzimski, Z.J.

The electrical activity of as-grown and intentionally decorated misfit dislocations in an epitaxial Si/Si(Ge) heterostructure was examined using the electron beam induced current (EBIC) technique in a scanning electron microscope. Misfit dislocations, which were not visible initially, were subsequently activated either by an unknown processing contaminant or a backside metallic impurity. Passivation of these contaminated dislocations was then studied using low energy deuterium ion implantation in a Kaufman ion source. EBIC results show that the recombination activity of the decorated misfit dislocations was dramatically reduced by the deuterium treatment. Although a front side passivation treatment was more effective than amore » backside treatment, a surface ion bombardment damage problem is still evident. 5 refs., 3 figs.« less

High voltage pulse conditioning

DOEpatents

Springfield, Ray M.; Wheat, Jr., Robert M.

1990-01-01

Apparatus for conditioning high voltage pulses from particle accelerators in order to shorten the rise times of the pulses. Flashover switches in the cathode stalk of the transmission line hold off conduction for a determinable period of time, reflecting the early portion of the pulses. Diodes upstream of the switches divert energy into the magnetic and electrostatic storage of the capacitance and inductance inherent to the transmission line until the switches close.

Lithium-based surfaces controlling fusion plasma behavior at the plasma-material interfacea)

NASA Astrophysics Data System (ADS)

Allain, Jean Paul; Taylor, Chase N.

2012-05-01

The plasma-material interface and its impact on the performance of magnetically confined thermonuclear fusion plasmas are considered to be one of the key scientific gaps in the realization of nuclear fusion power. At this interface, high particle and heat flux from the fusion plasma can limit the material's lifetime and reliability and therefore hinder operation of the fusion device. Lithium-based surfaces are now being used in major magnetic confinement fusion devices and have observed profound effects on plasma performance including enhanced confinement, suppression and control of edge localized modes (ELM), lower hydrogen recycling and impurity suppression. The critical spatial scale length of deuterium and helium particle interactions in lithium ranges between 5-100 nm depending on the incident particle energies at the edge and magnetic configuration. Lithium-based surfaces also range from liquid state to solid lithium coatings on a variety of substrates (e.g., graphite, stainless steel, refractory metal W/Mo/etc., or porous metal structures). Temperature-dependent effects from lithium-based surfaces as plasma facing components (PFC) include magnetohydrodynamic (MHD) instability issues related to liquid lithium, surface impurity, and deuterium retention issues, and anomalous physical sputtering increase at temperatures above lithium's melting point. The paper discusses the viability of lithium-based surfaces in future burning-plasma environments such as those found in ITER and DEMO-like fusion reactor devices.

Characteristics of plasma-puff trigger for a inverse-pinch plasma switch

NASA Technical Reports Server (NTRS)

Choi, Eun H.; Venable, Demetrius D.; Han, Kwang S.; Lee, Ja H.

1993-01-01

The plasma-puff triggering mechanism based on a hypocycloidal pinch geometry was investigated to determine the optimal operating conditions for the azimuthally uniform surface flashover which initiates plasma-puff under wide ranges of fill gas pressure of Ar, He and N2. The optimal fill-gas pressure range for the azimuthally uniform plasma-puff was about 120 mTorr less than or equal to P(sub op) less than or equal to 450 Torr for He and N2. For Argon 120 mTorr is less than or equal to P(sub op) is less than or equal to 5 Torr. The inverse-pinch switch was triggered with the plasma-puff and the switching capability under various electrical parameters and working gas pressures of Ar, He and N2 was determined. The azimuthally uniform switching discharges were dependent on the type of fill gas and its fill pressure. A new concept of plasma-focus driven plasma-puff will be discussed in comparison with the current hypocycloidal-pinch plasma-puff triggering.

Modified corrosion protection coatings for Concrete tower of Transmission line

NASA Astrophysics Data System (ADS)

Guo, Kai; Jing, Xiangyang; Wang, Hongli; Yue, Zengwu; Wu, Yaping; Mi, Xuchun; Li, Xingeng; Chen, Suhong; Fan, Zhibin

2017-12-01

By adding nano SiO2 particles, an enhanced K-PRTV anti-pollution flashover coating had been prepared. Optical profile meter (GT-K), atomic force microscopy (AFM) and infrared spectrometer (FT-IR) characterization were carried out on the coating surface analysis. With the use of modified epoxy resin as the base material, the supplemented by phosphate as a corrosion stabilizer, to achieve a corrosion of steel and galvanized steel with rust coating. Paint with excellent adhesion, more than 10MPa (1), resistant to neutral salt spray 1000h does not appear rust point. At the same time coating a large amount of ultra-fine zinc powder can be added for the tower galvanized layer zinc repair function, while the paint in the zinc powder for the tower to provide sacrificial anode protection, to achieve self-repair function of the coating. Compared to the market with a significant reduction in the cost of rust paint, enhance the anti-corrosion properties.

Temperature dependence of deuterium retention mechanisms in tungsten

NASA Astrophysics Data System (ADS)

Roszell, J. P.; Davis, J. W.; Haasz, A. A.

2012-10-01

The retention of 500 eV D+ was measured as a function of implantation temperature in single- (SCW) and poly-crystalline (PCW) tungsten. The results show a decrease in retention of ˜2 orders of magnitude over the temperature range of 350-550 K in SCW and a decrease of an order of magnitude over the temperature range of 600-700 K in PCW. Inspection of the TDS spectra showed a shift in peak location from 600 to 800 K as temperature was increased above 350 K in SCW and above 450 K in PCW specimens. TMAP modeling showed that the change in peak location corresponds to a change in trapping energy from 1.3 eV for the 600 K peak to 2.1 eV for the 800 K peak. It is proposed that for implantations performed above 350 K in SCW and 450 K in PCW, deuterium-containing vacancies are able to diffuse and combine to create stable nano-bubbles within the crystal lattice. The formation of nano-bubbles due to the annihilation of deuterium-vacancy complexes results in a change in the trapping energy from 1.3 to 2.1 eV as well as a decrease in retention as some of the deuterium-vacancy complexes will be destroyed at surfaces or grain boundaries, decreasing the number of trapping sites available.

DEUTERIUM BURNING IN MASSIVE GIANT PLANETS AND LOW-MASS BROWN DWARFS FORMED BY CORE-NUCLEATED ACCRETION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bodenheimer, Peter; D'Angelo, Gennaro; Lissauer, Jack J.

Using detailed numerical simulations, we study the formation of bodies near the deuterium-burning limit according to the core-nucleated giant planet accretion scenario. The objects, with heavy-element cores in the range 5-30 M{sub Circled-Plus }, are assumed to accrete gas up to final masses of 10-15 Jupiter masses (M{sub Jup}). After the formation process, which lasts 1-5 Myr and which ends with a ''cold-start'', low-entropy configuration, the bodies evolve at constant mass up to an age of several Gyr. Deuterium burning via proton capture is included in the calculation, and we determined the mass, M{sub 50}, above which more than 50%more » of the initial deuterium is burned. This often-quoted borderline between giant planets and brown dwarfs is found to depend only slightly on parameters, such as core mass, stellar mass, formation location, solid surface density in the protoplanetary disk, disk viscosity, and dust opacity. The values for M{sub 50} fall in the range 11.6-13.6 M{sub Jup}, in agreement with previous determinations that do not take the formation process into account. For a given opacity law during the formation process, objects with higher core masses form more quickly. The result is higher entropy in the envelope at the completion of accretion, yielding lower values of M{sub 50}. For masses above M{sub 50}, during the deuterium-burning phase, objects expand and increase in luminosity by one to three orders of magnitude. Evolutionary tracks in the luminosity versus time diagram are compared with the observed position of the companion to Beta Pictoris.« less

Measurement of the ratio of hydrogen to deuterium at the KSTAR 2009 experimental campaign

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kwak, Jong-Gu; Wang, Son Jong; Kim, Sun Ho

The control of the ratio of hydrogen to the deuterium is one of the very important issues for ion cyclotron range of frequency (ICRF) minority heating as well as the plasma wall interaction in the tokamak. The ratio of hydrogen to deuterium during the tokamak shot was deduced from the emission spectroscopy measurements during the KSTAR 2009 experimental campaign. Graphite tiles were used for the plasma facing components (PFCs) at KSTAR and its surface area exposed to the plasma was about 11 m{sup 2}. The data showed that it remained as high as around 50% during the campaign period becausemore » graphite tiles were exposed to the air for about two months and the hydrogen contents at the tiles are not fully pumped out due to the lack of baking on the PFC in the 2009 campaign. The validation of the spectroscopy method was checked by using the Zeeman effects and the ratio of hydrogen to the deuterium is compared with results from the residual gas analysis. During the tokamak shot, the ratio is low below 10% initially and saturated after around 1 s. When there is a hydrogen injection to the vessel via ion cyclotron wall conditioning and the boronization process where the carbone is used, the ratio of the hydrogen to the deuterium is increased by up to 100% and it recovers to around 50% after one day of operation. However it does not decrease below 50% at the end of the experimental campaign. It was found that the full baking on the PFC (with a high temperature and sufficient vacuum pumping) is required for the ratio control which guarantees the efficient ICRF heating at the KSTAR 2010 experimental campaign.« less

Modeling Insights into Deuterium Excess as an Indicator of Water Vapor Source Conditions

NASA Technical Reports Server (NTRS)

Lewis, Sophie C.; Legrande, Allegra Nicole; Kelley, Maxwell; Schmidt, Gavin A.

2013-01-01

Deuterium excess (d) is interpreted in conventional paleoclimate reconstructions as a tracer of oceanic source region conditions, such as temperature, where precipitation originates. Previous studies have adopted co-isotopic approaches to estimate past changes in both site and oceanic source temperatures for ice core sites using empirical relationships derived from conceptual distillation models, particularly Mixed Cloud Isotopic Models (MCIMs). However, the relationship between d and oceanic surface conditions remains unclear in past contexts. We investigate this climate-isotope relationship for sites in Greenland and Antarctica using multiple simulations of the water isotope-enabled Goddard Institute for Space Studies (GISS) ModelE-R general circulation model and apply a novel suite of model vapor source distribution (VSD) tracers to assess d as a proxy for source temperature variability under a range of climatic conditions. Simulated average source temperatures determined by the VSDs are compared to synthetic source temperature estimates calculated using MCIM equations linking d to source region conditions. We show that although deuterium excess is generally a faithful tracer of source temperatures as estimated by the MCIM approach, large discrepancies in the isotope-climate relationship occur around Greenland during the Last Glacial Maximum simulation, when precipitation seasonality and moisture source regions were notably different from present. This identified sensitivity in d as a source temperature proxy suggests that quantitative climate reconstructions from deuterium excess should be treated with caution for some sites when boundary conditions are significantly different from the present day. Also, the exclusion of the influence of humidity and other evaporative source changes in MCIM regressions may be a limitation of quantifying source temperature fluctuations from deuterium excess in some instances.

Structural Transformations in Austenitic Stainless Steel Induced by Deuterium Implantation: Irradiation at 295 K

NASA Astrophysics Data System (ADS)

Morozov, Oleksandr; Zhurba, Volodymir; Neklyudov, Ivan; Mats, Oleksandr; Progolaieva, Viktoria; Boshko, Valerian

2016-02-01

Deuterium thermal desorption spectra were investigated on the samples of austenitic steel 18Cr10NiTi pre-implanted at 295 K with deuterium ions in the dose range from 8 × 1014 to 2.7 × 1018 D/cm2. The kinetics of structural transformation development in the steel layer was traced from deuterium thermodesorption spectra as a function of deuterium concentration. Three characteristic regions with different low rates of deuterium amount desorption as the implantation dose increases were revealed: I—the linear region of low implantation doses (up to 1 × 1017 D/cm2); II—the nonlinear region of medium implantation doses (1 × 1017 to 8 × 1017 D/cm2); III—the linear region of high implantation doses (8 × 1017 to 2.7 × 1018 D/cm2). During the process of deuterium ion irradiation, the coefficient of deuterium retention in steel varies in discrete steps. Each of the discrete regions of deuterium retention coefficient variation corresponds to different implanted-matter states formed during deuterium ion implantation. The low-dose region is characterized by formation of deuterium-vacancy complexes and solid-solution phase state of deuterium in the steel. The total concentration of the accumulated deuterium in this region varies between 2.5 and 3 at.%. The medium-dose region is characterized by the radiation-induced action on the steel in the presence of deuterium with the resulting formation of the energy-stable nanosized crystalline structure of steel, having a developed network of intercrystalline boundaries. The basis for this developed network of intercrystalline boundaries is provided by the amorphous state, which manifests itself in the thermodesorption spectra as a widely temperature-scale extended region of deuterium desorption (structure formation with a varying activation energy). The total concentration of the accumulated deuterium in the region of medium implantation doses makes 7 to 8 at.%. The resulting structure shows stability against the action of deuterium ion implantation. This manifests itself in a nearly complete ceasing of deuterium accumulation from a newly implanted dose (radiation-resistant structure).

The Effects of Temperature and Oxidation on Deuterium Retention in Solid and Liquid Lithium Films on Molybdenum Plasma-Facing Components

NASA Astrophysics Data System (ADS)

Capece, Angela

2014-10-01

Liquid metal plasma-facing components (PFCs) enable in-situ renewal of the surface, thereby offering a solution to neutron damage, erosion, and thermal fatigue experienced by solid PFCs. Lithium in particular has a high chemical affinity for hydrogen, which has resulted in reduced recycling and enhanced plasma performance on many fusion devices including TFTR, T11-M, FTU, CDX-U, LTX, TJ-II, and NSTX. A key component to the improvement in plasma performance is deuterium retention in Li; however, this process is not well understood in the complex tokamak environment. Recent surface science experiments conducted at the Princeton Plasma Physics Laboratory have used electron spectroscopy and temperature programmed desorption to understand the mechanisms for D retention in Li coatings on Mo substrates. The experiments were designed to give monolayer-control of Li films and were conducted in ultrahigh vacuum under controlled environments. An electron cyclotron resonance plasma source was used to deliver a beam of deuterium ions to the surface over a range of ion energies. Our work shows that D is retained as LiD in metallic Li films. However, when oxygen is present in the film, either by diffusion from the subsurface at high temperature or as a contaminant during the deposition process, Li oxides are formed that retain D as LiOD. Experiments indicate that LiD is more thermally stable than LiOD, which decomposes to liberate D2 gas and D2O at temperatures 100 K lower than the LiD decomposition temperature. Other experiments show how D retention varies with substrate temperature to provide insight into the differences between solid and liquid lithium films. This work was supported by DOE Contract No. DE AC02-09CH11466.

Effects of temperature and surface contamination on D retention in ultrathin Li films on TZM

DOE PAGES

Capece, A. M.; Roszell, J. P.; Skinner, C. H.; ...

2014-10-29

Here in this work, we investigate deuterium retention at the Mo-Li interface by studying thin Li films three monolayers thick on a TZM Mo alloy. Li films at temperatures between 315 and 460 K were exposed to a deuterium ion beam and D retention was measured using temperature programmed desorption. In the absence of oxygen, D is retained as LiD, and the relative amount of retained D decreases with increasing substrate temperature. In three-monolayer thick lithium oxide films, the amount of D retained was 2.5 times higher than the amount retained as LiD in the metallic Li film. However, oxygenmore » reduces the thermal stability of D in the film, causing D 2O and D 2 to be released from the surface at temperatures 150-200 K below the LiD decomposition temperature. These results highlight the importance of maintaining a metallic Li layer for high D retention in Li films on TZM at elevated temperatures.« less

Effects of temperature and surface contamination on D retention in ultrathin Li films on TZM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Capece, A. M.; Roszell, J. P.; Skinner, C. H.

Here in this work, we investigate deuterium retention at the Mo-Li interface by studying thin Li films three monolayers thick on a TZM Mo alloy. Li films at temperatures between 315 and 460 K were exposed to a deuterium ion beam and D retention was measured using temperature programmed desorption. In the absence of oxygen, D is retained as LiD, and the relative amount of retained D decreases with increasing substrate temperature. In three-monolayer thick lithium oxide films, the amount of D retained was 2.5 times higher than the amount retained as LiD in the metallic Li film. However, oxygenmore » reduces the thermal stability of D in the film, causing D 2O and D 2 to be released from the surface at temperatures 150-200 K below the LiD decomposition temperature. These results highlight the importance of maintaining a metallic Li layer for high D retention in Li films on TZM at elevated temperatures.« less

Structural Transformations in Austenitic Stainless Steel Induced by Deuterium Implantation: Irradiation at 295 K.

PubMed

Morozov, Oleksandr; Zhurba, Volodymir; Neklyudov, Ivan; Mats, Oleksandr; Progolaieva, Viktoria; Boshko, Valerian

2016-12-01

Deuterium thermal desorption spectra were investigated on the samples of austenitic steel 18Cr10NiTi pre-implanted at 295 K with deuterium ions in the dose range from 8 × 10(14) to 2.7 × 10(18) D/cm(2). The kinetics of structural transformation development in the steel layer was traced from deuterium thermodesorption spectra as a function of deuterium concentration. Three characteristic regions with different low rates of deuterium amount desorption as the implantation dose increases were revealed: I-the linear region of low implantation doses (up to 1 × 10(17) D/cm(2)); II-the nonlinear region of medium implantation doses (1 × 10(17) to 8 × 10(17) D/cm(2)); III-the linear region of high implantation doses (8 × 10(17) to 2.7 × 10(18) D/cm(2)). During the process of deuterium ion irradiation, the coefficient of deuterium retention in steel varies in discrete steps. Each of the discrete regions of deuterium retention coefficient variation corresponds to different implanted-matter states formed during deuterium ion implantation. The low-dose region is characterized by formation of deuterium-vacancy complexes and solid-solution phase state of deuterium in the steel. The total concentration of the accumulated deuterium in this region varies between 2.5 and 3 at.%. The medium-dose region is characterized by the radiation-induced action on the steel in the presence of deuterium with the resulting formation of the energy-stable nanosized crystalline structure of steel, having a developed network of intercrystalline boundaries. The basis for this developed network of intercrystalline boundaries is provided by the amorphous state, which manifests itself in the thermodesorption spectra as a widely temperature-scale extended region of deuterium desorption (structure formation with a varying activation energy). The total concentration of the accumulated deuterium in the region of medium implantation doses makes 7 to 8 at.%. The resulting structure shows stability against the action of deuterium ion implantation. This manifests itself in a nearly complete ceasing of deuterium accumulation from a newly implanted dose (radiation-resistant structure).

Vacuum Flashover Characteristics of Laminated Polystyrene Insulators

DTIC Science & Technology

1999-06-01

space charge dominated. A minimum wafer thickness and/or the number of wafers required for the application can be calculated. Equation 1 represents...toward the anode. qn is the fraction of charge deposited on that section of the stack. Equation 1 comes from the assumption that a space charge ...Rodriguez, A.E., and Honig, E.M., "Characterization of an Insulated Space Charge Limited Non-Relativistic Electron Beam Diode Operating at 300 kV/cm

Kapton wire concerns for aerospace vehicles

NASA Technical Reports Server (NTRS)

Vanlaak, J.

1994-01-01

This presentation outlines the background to the concern of using Kapton wire for aerospace vehicles and proposes it should not be utilized in new builds for spacecraft power applications. A NASA HQ investigation concluded that the risk of Kapton arc-tracking/flashover is a credible threat to the shuttle orbiter, but rationale is presented for continued flight for the time being. Recommendations for the protection of the shuttle and the build of the space station are given.

Deuterium desorption from ion-irradiated tantalum and effects on surface morphology

NASA Astrophysics Data System (ADS)

Novakowski, T. J.; Sundaram, A.; Tripathi, J. K.; Gonderman, S.; Hassanein, A.

2018-06-01

Compared to tungsten (W), tantalum (Ta) has shown superior resistance to helium (He)-induced surface morphology changes under fusion-relevant irradiation conditions. However, Ta is also expected to have a stronger interaction with hydrogen isotopes, potentially limiting its use as a plasma-facing material. Despite these concerns, detailed investigations on hydrogen irradiation effects on Ta are scarce. In this study, pristine and fuzzy (He+ ion-irradiated) Ta samples are irradiated with 120 eV deuterium (D) ions at various temperatures and examined with a combination of thermal desorption spectroscopy (TDS), scanning electron microscopy (SEM), and optical reflectivity. TDS reveals discrete D desorption temperatures at 660 and 760 K, corresponding to trapping energies of 1.82 and 2.11 eV, respectively. Although D is retained in Ta both in higher quantities and at higher temperatures compared to W, extreme surface temperatures expected in tokamak divertors may exceed these desorption temperatures and counteract retention. Furthermore, this study indicates that Ta is relatively resistant to adverse surface structuring under D+ ion irradiation. In fact, D+ is shown to prevent and suppress Ta fuzz formation in sequential D+/He+ ion irradiation experiments. While further investigations are needed to elucidate this behavior, these initial investigations show a strong potential for the use of Ta as a PFC material.

Deuterium supersaturation in low-energy plasma-loaded tungsten surfaces

NASA Astrophysics Data System (ADS)

Gao, L.; Jacob, W.; von Toussaint, U.; Manhard, A.; Balden, M.; Schmid, K.; Schwarz-Selinger, T.

2017-01-01

Fundamental understanding of hydrogen-metal interactions is challenging due to a lack of knowledge on defect production and/or evolution upon hydrogen ingression, especially for metals undergoing hydrogen irradiation with ion energy below the displacement thresholds reported in literature. Here, applying a novel low-energy argon-sputter depth profiling method with significantly improved depth resolution for tungsten (W) surfaces exposed to deuterium (D) plasma at 300 K, we show the existence of a 10 nm thick D-supersaturated surface layer (DSSL) with an unexpectedly high D concentration of ~10 at.% after irradiation with ion energy of 215 eV. Electron back-scatter diffraction reveals that the W lattice within this DSSL is highly distorted, thus strongly blurring the Kikuchi pattern. We explain this strong damage by the synergistic interaction of energetic D ions and solute D atoms with the W lattice. Solute D atoms prevent the recombination of vacancies with interstitial W atoms, which are produced by collisions of energetic D ions with W lattice atoms (Frenkel pairs). This proposed damaging mechanism could also be active on other hydrogen-irradiated metal surfaces. The present work provides deep insight into hydrogen-induced lattice distortion at plasma-metal interfaces and sheds light on its modelling work.

Isotopic Probe Illuminates the Role of the Electrode Surface in Proton Coupled Hydride Transfer Electrochemical Reduction of Pyridinium on Pt(111)

DOE PAGES

Zeitler, Elizabeth L.; Ertem, Mehmed Z.; Pander, III, James E.; ...

2015-10-21

A recently proposed mechanism for electrochemical CO 2 reduction on Pt (111) catalyzed by aqueous acidic pyridine solutions suggests that the observed redox potential of ca. -600 mV vs. SCE is due to the one-electron reduction of pyridinium through proton coupled electron transfer (PCET) to form H atoms adsorbed on the Pt surface (H ads). The initial pyridinium reduction was probed isotopically via deuterium substitution. A combined experimental and theoretical analysis found equilibrium isotope effects (EIE) due to deuterium substitution at the acidic pyridinium site. A shift in the cathodic cyclic voltammetric half wave potential of -25 mV was observed,more » consistent with the theoretical prediction of -40 mV based on the recently proposed reaction mechanism where pyridinium is essential to establish a high concentration of Bronsted acid in contact with the substrate CO 2 and with the Pt surface. A prefeature in the cyclic voltammogram was examined under isotopic substitution and indicated an H-ads intermediate in pyridinium reduction. In conclusion, the theoretical prediction and observation of an BM supported the assignment of the cathodic wave to the proposed reduction of pyridinium through PCET forming H ads and eventually H 2 on the Pt surface.« less

SAIDE: A Semi-Automated Interface for Hydrogen/Deuterium Exchange Mass Spectrometry.

PubMed

Villar, Maria T; Miller, Danny E; Fenton, Aron W; Artigues, Antonio

2010-01-01

Deuterium/hydrogen exchange in combination with mass spectrometry (DH MS) is a sensitive technique for detection of changes in protein conformation and dynamics. Since temperature, pH and timing control are the key elements for reliable and efficient measurement of hydrogen/deuterium content in proteins and peptides, we have developed a small, semiautomatic interface for deuterium exchange that interfaces the HPLC pumps with a mass spectrometer. This interface is relatively inexpensive to build, and provides efficient temperature and timing control in all stages of enzyme digestion, HPLC separation and mass analysis of the resulting peptides. We have tested this system with a series of standard tryptic peptides reconstituted in a solvent containing increasing concentration of deuterium. Our results demonstrate the use of this interface results in minimal loss of deuterium due to back exchange during HPLC desalting and separation. For peptides reconstituted in a buffer containing 100% deuterium, and assuming that all amide linkages have exchanged hydrogen with deuterium, the maximum loss of deuterium content is only 17% of the label, indicating the loss of only one deuterium molecule per peptide.

SAIDE: A Semi-Automated Interface for Hydrogen/Deuterium Exchange Mass Spectrometry

PubMed Central

Villar, Maria T.; Miller, Danny E.; Fenton, Aron W.; Artigues, Antonio

2011-01-01

Deuterium/hydrogen exchange in combination with mass spectrometry (DH MS) is a sensitive technique for detection of changes in protein conformation and dynamics. Since temperature, pH and timing control are the key elements for reliable and efficient measurement of hydrogen/deuterium content in proteins and peptides, we have developed a small, semiautomatic interface for deuterium exchange that interfaces the HPLC pumps with a mass spectrometer. This interface is relatively inexpensive to build, and provides efficient temperature and timing control in all stages of enzyme digestion, HPLC separation and mass analysis of the resulting peptides. We have tested this system with a series of standard tryptic peptides reconstituted in a solvent containing increasing concentration of deuterium. Our results demonstrate the use of this interface results in minimal loss of deuterium due to back exchange during HPLC desalting and separation. For peptides reconstituted in a buffer containing 100% deuterium, and assuming that all amide linkages have exchanged hydrogen with deuterium, the maximum loss of deuterium content is only 17% of the label, indicating the loss of only one deuterium molecule per peptide. PMID:25309638

Quantum diffusion of H/D on Ni(111)—A partially adiabatic centroid MD study

NASA Astrophysics Data System (ADS)

Hopkinson, A. R.; Probert, M. I. J.

2018-03-01

We present the results of a theoretical study of H/D diffusion on a Ni(111) surface at a range of temperatures, from 250 K to 75 K. The diffusion is studied using both classical molecular dynamics and the partially adiabatic centroid molecular dynamics method. The calculations are performed with the hydrogen (or deuterium) moving in 3D across a static nickel surface using a novel Fourier interpolated potential energy surface which has been parameterized to density functional theory calculations. The results of the classical simulations are that the calculated diffusion coefficients are far too small and with too large a variation with temperature compared with experiment. By contrast, the quantum simulations are in much better agreement with experiment and show that quantum effects in the diffusion of hydrogen are significant at all temperatures studied. There is also a crossover to a quantum-dominated diffusive regime for temperatures below ˜150 K for hydrogen and ˜85 K for deuterium. The quantum diffusion coefficients are found to accurately reproduce the spread in values with temperature, but with an absolute value that is a little high compared with experiment.

Erosion and Retention Properties of Beyllium

NASA Astrophysics Data System (ADS)

Doerner, R.; Grossman, A.; Luckhardt, S.; Serayderian, R.; Sze, F. C.; Whyte, D. G.

1997-11-01

Experiments in PISCES-B have investigated the erosion and hydrogen retention characteristics of beryllium. The sputtering yield is strongly influenced by trace amounts (≈1 percent) of intrinsic plasma impurities. At low sample exposure temperatures (below 250^oC), the beryllium surface remains free of contaminants and a sputtering yield similar to that of beryllium-oxide is measured. At higher exposure temperatures, impurities deposited on the surface can diffuse into the bulk and reduce their chance of subsequent erosion. These impurities form a surface layer mixed with beryllium which exhibits a reduced sputtering yield. Depth profile analysis has determined the composition and chemical bonding of the impurity layer. The hydrogen isotope retention of beryllium under ITER first wall (temperature = 200^oC, ion flux = 1 x 10^21 m-2 s-1) and baffle (temperature = 500^oC, ion flux = 1 x 10^22 m-2 s-1) conditions has been investigated. The retained deuterium saturates above a fluence of 10^23 m-2 at about 4 x 10^20 m-2 for the 200^oC exposure and at 2 x 10^20 m-2 for the 500^oC case. The TMAP code is used to model the deuterium release characteristics.

Behavior of deuterium retention and surface morphology for VPS–W/F82H

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yasuhisa Oya; Masashi Shimada; Tomonori Tokunaga

The deuterium (D) retention for Vacuum Plasma Spray (VPS)–tungsten (W)/F82H was studied using two different implantation methods, namely D plasma exposure and View the MathML source implantation. The D retention for polished VPS–W/F82H after plasma exposure was found to be reduced compared to that for polycrystalline tungsten. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations indicated that porous structures around grain boundaries and the interface between VPS–W layers would be potential D diffusion paths, leading to low D retention. In the case of View the MathML source implantation, the shape of D2 TDS spectrum was almost the samemore » as that for D plasma-exposed VPS–W/F82H; however, the D retention was quite high for unpolished VPS–W/F82H, indicating that most of D was trapped by the oxide layer, which was produced by the VPS process. The reduction of surface area due to the polishing process also reduces D retention for VPS–W/F82H. These results indicate that controlling the surface chemical states is important for the reduction of tritium retention for future fusion reactors.« less

Development of positron annihilation spectroscopy for investigating deuterium decorated voids in neutron-irradiated tungsten

NASA Astrophysics Data System (ADS)

Taylor, C. N.; Shimada, M.; Merrill, B. J.; Akers, D. W.; Hatano, Y.

2015-08-01

The present work is a continuation of a recent research to develop and optimize positron annihilation spectroscopy (PAS) for characterizing neutron-irradiated tungsten. Tungsten samples were exposed to neutrons in the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory and damaged to 0.025 and 0.3 dpa. Subsequently, they were exposed to deuterium plasmas in the Tritium Plasma Experiment (TPE) at Idaho National Laboratory. The implanted deuterium was desorbed through sample heating to 900 °C, and Doppler broadening (DB)-PAS was performed both before and after heating. Results show that deuterium impregnated tungsten is identified as having a smaller S-parameter. The S-parameter increases after deuterium desorption. Microstructural changes also occur during sample heating. These effects can be isolated from deuterium desorption by comparing the S-parameters from the deuterium-free back face with the deuterium-implanted front face. The application of using DB-PAS to examine deuterium retention in tungsten is examined.

Distribution of deuterium and hydrogen in Zr and Ti foil assemblies under the action of a pulsed deuterium high-temperature plasma

NASA Astrophysics Data System (ADS)

Bondarenko, G. G.; Volobuev, I. V.; Eriskin, A. A.; Kobzev, A. P.; Nikulin, V. Ya.; Peregudova, E. N.; Silin, P. V.; Borovitskaya, I. V.

2017-09-01

Deuteron and proton elastic recoil detection analysis is used to study the accumulation and redistribution of deuterium and hydrogen in assemblies of two high-pure zirconium or titanium foils upon pulsed action of high-temperature deuterium plasma (PHTDP) in a plasma-focus installation PF-4. It is noted that, under the action of PHTDP, an implanted deuterium and hydrogen gas impurity are redistributed in the irradiated foils in large depths, which are significantly larger than the deuterium ion free paths (at their maximum velocity to 108 cm/s). The observed phenomenon is attributed to the carrying out of implanted deuterium and hydrogen under the action of powerful shock waves formed in the metallic foils under the action of PHTDP and/or the acceleration of diffusion of deuterium and hydrogen atoms under the action of a compression-rarefaction shock wave at the shock wave front with the redistribution of deuterium and hydrogen to large depths.

Structural transformations in austenitic stainless steel induced by deuterium implantation: irradiation at 100 K

NASA Astrophysics Data System (ADS)

Morozov, Oleksandr; Zhurba, Volodymyr; Neklyudov, Ivan; Mats, Oleksandr; Rud, Aleksandr; Chernyak, Nikolay; Progolaieva, Viktoria

2015-03-01

Deuterium thermal desorption spectra were investigated on the samples of austenitic stainless steel 18Cr10NiTi preimplanted at 100 K with deuterium ions in the dose range from 3 × 1015 to 5 × 1018 D/cm2. The kinetics of structural transformation development in the implantation steel layer was traced from deuterium thermodesorption spectra as a function of implanted deuterium concentration. At saturation of austenitic stainless steel 18Cr10NiTi with deuterium by means of ion implantation, structural-phase changes take place, depending on the dose of implanted deuterium. The maximum attainable concentration of deuterium in steel is C = 1 (at.D/at.met. = 1/1). The increase in the implanted dose of deuterium is accompanied by the increase in the retained deuterium content, and as soon as the deuterium concentration attains C ≈ 0.5 the process of shear martensitic structural transformation in steel takes place. It includes the formation of bands, body-centered cubic (bcc) crystal structure, and the ferromagnetic phase. Upon reaching the deuterium concentration C > 0.5, the presence of these molecules causes shear martensitic structural transformations in the steel, which include the formation of characteristic bands, bcc crystal structure, and the ferromagnetic phase. At C ≥ 0.5, two hydride phases are formed in the steel, the decay temperatures of which are 240 and 275 K. The hydride phases are formed in the bcc structure resulting from the martensitic structural transformation in steel.

Single crystal diamond detector measurements of deuterium-deuterium and deuterium-tritium neutrons in Joint European Torus fusion plasmas.

PubMed

Cazzaniga, C; Sundén, E Andersson; Binda, F; Croci, G; Ericsson, G; Giacomelli, L; Gorini, G; Griesmayer, E; Grosso, G; Kaveney, G; Nocente, M; Perelli Cippo, E; Rebai, M; Syme, B; Tardocchi, M

2014-04-01

First simultaneous measurements of deuterium-deuterium (DD) and deuterium-tritium neutrons from deuterium plasmas using a Single crystal Diamond Detector are presented in this paper. The measurements were performed at JET with a dedicated electronic chain that combined high count rate capabilities and high energy resolution. The deposited energy spectrum from DD neutrons was successfully reproduced by means of Monte Carlo calculations of the detector response function and simulations of neutron emission from the plasma, including background contributions. The reported results are of relevance for the development of compact neutron detectors with spectroscopy capabilities for installation in camera systems of present and future high power fusion experiments.

On-tissue Direct Monitoring of Global Hydrogen/Deuterium Exchange by MALDI Mass Spectrometry: Tissue Deuterium Exchange Mass Spectrometry (TDXMS)*

PubMed Central

Quanico, Jusal; Franck, Julien

2016-01-01

Hydrogen/deuterium exchange mass spectrometric (H/DXMS) methods for protein structural analysis are conventionally performed in solution. We present Tissue Deuterium Exchange Mass Spectrometry (TDXMS), a method to directly monitor deuterium uptake on tissue, as a means to better approximate the deuterium exchange behavior of proteins in their native microenvironment. Using this method, a difference in deuterium uptake behavior was observed when the same proteins were monitored in solution and on tissue. The higher maximum deuterium uptake at equilibrium for all proteins analyzed in solution suggests a more open conformation in the absence of interacting partners normally observed on tissue. We also demonstrate a difference in the deuterium uptake behavior of a few proteins across different morphological regions of the same tissue section. Modifications of the total number of hydrogens exchanged, as well as the kinetics of exchange, were both observed. These results provide information on the implication of protein interactions with partners as well as on the conformational changes related to these interactions, and illustrate the importance of examining protein deuterium exchange behavior in the presence of its specific microenvironment directly at the level of tissues. PMID:27512083

Protein and Peptide Gas-phase Structure Investigation Using Collision Cross Section Measurements and Hydrogen Deuterium Exchange

NASA Astrophysics Data System (ADS)

Khakinejad, Mahdiar

Protein and peptide gas-phase structure analysis provides the opportunity to study these species outside of their explicit environment where the interaction network with surrounding molecules makes the analysis difficult [1]. Although gas-phase structure analysis offers a unique opportunity to study the intrinsic behavior of these biomolecules [2-4], proteins and peptides exhibit very low vapor pressures [2]. Peptide and protein ions can be rendered in the gas-phase using electrospray ionization (ESI) [5]. There is a growing body of literature that shows proteins and peptides can maintain solution structures during the process of ESI and these structures can persist for a few hundred milliseconds [6-9]. Techniques for monitoring gas-phase protein and peptide ion structures are categorized as physical probes and chemical probes. Collision cross section (CCS) measurement, being a physical probe, is a powerful method to investigate gas-phase structure size [3, 7, 10-15]; however, CCS values alone do not establish a one to one relation with structure(i.e., the CCS value is an orientationally averaged value [15-18]. Here we propose the utility of gas-phase hydrogen deuterium exchange (HDX) as a second criterion of structure elucidation. The proposed approach incudes extensive MD simulations to sample biomolecular ion conformation space with the production of numerous, random in-silico structures. Subsequently a CCS can be calculated for these structures and theoretical CCS values are compared with experimental values to produce a pool of candidate structures. Utilizing a chemical reaction model based on the gas-phase HDX mechanism, the HDX kinetics behavior of these candidate structures are predicted and compared to experimental results to nominate the best in-silico structures which match (chemically and physically) with experimental observations. For the predictive approach to succeed, an extensive technique and method development is essential. To combine CCS measurements and gas-phase HDX studies at the amino acid residue level, for the first time a drift tube is connected to a linear ion trap (LIT) with electron transfer dissociation (ETD) capability[19, 20]. In this manner CCS and per-residue deuterium uptake measurements for a model peptide carried out successfully[19]. In this study, the gas-phase conformations of electrosprayed ions of the model peptide KKDDDDIIKIIK have been examined. Using ion structures obtained from molecular dynamics (MD) simulation and considering charge-site/exchange-site density the level of the maximum total deuterium uptake for the gas-phase ions is explained. Also a new hydrogen accessibility scoring (HAS) model that includes two distance calculations (charge site to carbonyl group and carbonyl group to exchange site) is applied to the in-silico structures to describe the expected HDX behavior for these structures. Further investigation to improve the accuracy of the model is accomplished by a "per-residue" HDX kinetics study of the model peptide [21]. In this study, the ion residence time and the deuterium uptake of each residue is measured at different partial pressures of D2O. Subsequently the contribution each residue to the overall HDX rate of the intact peptide ion is calculated. These rate contributions of the residues exhibit a better fit to HAS than their maximum deuterium uptake. Proteins and peptides with very frequent acidic residue in their sequence provide very poor signal levels when employing positive polarity ESI. Also, the comparison of protonated and deprotonated ions of these biomolecules offers the potential to provide a better structural characterization [22]. Per-residue deuterium uptake values resulting from collision-induced dissociation (CID) of the model peptide KKDDDDIIKIIK were used to investigated the degree of hydrogen deuterium scrambling for deprotonated ions [23]. Remarkably, limited isotopic scrambling was observed in this study of this small model peptide. This data and the per-residue deuterium uptake of the triply-protonated model peptide Acetyl-PAAAAKAAAAKAAAAKAAAAK are exploited to propose a lemma to allocate protonation and deprotonation sites for peptide ions in the gas-phase. Insulin ions, as a small protein model system, are examined to investigate the relation of the maximum deuterium uptake value for each insulin chain to the exposed surface area of each insulin subunit [22]. The results show that the methodology can be applied on the protein complexes to provide information about the exposed surface area of each subunit.

An Advanced ESTCP PELAN System for Surface and Near-surface UXO Discrimination

DTIC Science & Technology

2009-03-01

system was designed and assembled at SAIC. Test slugs representing 30mm to 105mm shells were constructed and filled with inert materials and explosives...results and system design, ESTCP decided to discontinue the effort before the prototype was constructed and demonstrated. iii TABLE OF CONTENTS...RDX and non-explosive plasticizers ) cps counts per second CW Chemical Warfare agent d-T deuterium-tritium DoD Department of Defense DOE

Deuterium retention and release behaviours of tungsten and deuterium co-deposited layers

NASA Astrophysics Data System (ADS)

Qiao, L.; Zhang, H. W.; Xu, J.; Chai, L. Q.; Hu, M.; Wang, P.

2018-04-01

Tungsten (W) layer deposited in argon and deuterium atmosphere by magnetron sputtering was used as a model system to study the deuterium (D) retention and release behavior in co-deposited W layer. After deposition several selected samples were exposed in deuterium plasma at 370 K with a flux of 4.0 × 1021 D/(m2 s) up to a fluence of 1.1 × 1025 D/m2. Structures of co-deposited W layers are investigated by field-emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD), and the corresponding D retention and release behaviors are studied as functions of deposition and exposure parameters using thermal desorption spectroscopy (TDS). Two main D release peaks were detected from TDS spectra located near 600 and 800 K in these W and D co-deposited layers, and total deuterium retention increased linearly as a function of W layer's thickness. After deuterium plasma exposure, the total D retention amount in W layer increases significantly and D release peak shifts to lower temperature. Clearly, despite the high density of defects expected in co-deposited W layers, the initial deuterium retention before exposure to the deuterium plasma is low even for the samples with a W&D layer. But due to the high densities of defects, during the deuterium plasma exposure the deuterium retention increases faster for co-deposited layer than for the bulk W sample.

Fast MAS 1H NMR Study of Water Adsorption and Dissociation on the (100) Surface of Ceria Nanocubes: A Fully Hydroxylated, Hydrophobic Ceria Surface

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gill, Lance; Beste, Ariana; Chen, Banghao

1H nuclear magnetic resonance (NMR) spectroscopy was used to study hydroxylic surface species on ceria nanocubes, a crystalline, high-surface-area CeO 2 that presents mostly (100) facets. Water adsorption and desorption experiments in combination with fast magic angle spinning (MAS, 20–40 kHz) 1H NMR provide high-resolution 1H spectra that allow the observation of ten resonance bands (water or hydroxyl) on or under the (100) surface. Assignments were made using a combination of adsorption and temperature-programmed desorption, quantitative spin counting, deuterium exchange, spin–lattice (T 1) and spin–spin (T 2) relaxation, and DFT calculations. In air, the (100) surface exists as a fullymore » hydroxylated surface. Water adsorption and dissociation on dry ceria surfaces occur first at oxygen vacancies, but Ce 3+ centers are not required since water dissociation is barrier-less on the fully oxidized surface. Surface $-$OH functionality occurs in two resolved bands representing isolated $-$OH (1 ppm) and hydrogen-bonded $-$OH (9 ppm), the latter being dominant. Deuterium exchange of surface hydroxyls with D 2O does not occur under mild or forcing conditions. Despite large differences in the T 1 of surface hydroxyls and physisorbed water, surface hydroxyl T 1 values are independent of the presence or absence of physisorbed water, demonstrating that the protons within these two functional group pools are not in intimate contact. These observations show that, once hydroxylated, the surface $-$OH functionality preferentially forms hydrogen bonds with surface lattice oxygen, i.e., the hydroxylated (100) surface of ceria is hydrophobic. Near this surface it is energetically more favorable for physisorbed water to hydrogen bond to itself rather than to the surface. DFT calculations support this notion. Impurity Na + remaining in incompletely washed ceria nanocubes increases the surface hydrophilicity. In conclusion, sharp, low-field resonances observed in spectra of noncalcined nanocubes arise from kinetically trapped subsurface $-$OH.« less

Fast MAS 1H NMR Study of Water Adsorption and Dissociation on the (100) Surface of Ceria Nanocubes: A Fully Hydroxylated, Hydrophobic Ceria Surface

DOE PAGES

Gill, Lance; Beste, Ariana; Chen, Banghao; ...

2017-03-22

1H nuclear magnetic resonance (NMR) spectroscopy was used to study hydroxylic surface species on ceria nanocubes, a crystalline, high-surface-area CeO 2 that presents mostly (100) facets. Water adsorption and desorption experiments in combination with fast magic angle spinning (MAS, 20–40 kHz) 1H NMR provide high-resolution 1H spectra that allow the observation of ten resonance bands (water or hydroxyl) on or under the (100) surface. Assignments were made using a combination of adsorption and temperature-programmed desorption, quantitative spin counting, deuterium exchange, spin–lattice (T 1) and spin–spin (T 2) relaxation, and DFT calculations. In air, the (100) surface exists as a fullymore » hydroxylated surface. Water adsorption and dissociation on dry ceria surfaces occur first at oxygen vacancies, but Ce 3+ centers are not required since water dissociation is barrier-less on the fully oxidized surface. Surface $-$OH functionality occurs in two resolved bands representing isolated $-$OH (1 ppm) and hydrogen-bonded $-$OH (9 ppm), the latter being dominant. Deuterium exchange of surface hydroxyls with D 2O does not occur under mild or forcing conditions. Despite large differences in the T 1 of surface hydroxyls and physisorbed water, surface hydroxyl T 1 values are independent of the presence or absence of physisorbed water, demonstrating that the protons within these two functional group pools are not in intimate contact. These observations show that, once hydroxylated, the surface $-$OH functionality preferentially forms hydrogen bonds with surface lattice oxygen, i.e., the hydroxylated (100) surface of ceria is hydrophobic. Near this surface it is energetically more favorable for physisorbed water to hydrogen bond to itself rather than to the surface. DFT calculations support this notion. Impurity Na + remaining in incompletely washed ceria nanocubes increases the surface hydrophilicity. In conclusion, sharp, low-field resonances observed in spectra of noncalcined nanocubes arise from kinetically trapped subsurface $-$OH.« less

Direct depth distribution measurement of deuterium in bulk tungsten exposed to high-flux plasma

NASA Astrophysics Data System (ADS)

Taylor, C. N.; Shimada, M.

2017-05-01

Understanding tritium retention and permeation in plasma-facing components is critical for fusion safety and fuel cycle control. Glow discharge optical emission spectroscopy (GD-OES) is shown to be an effective tool to reveal the depth profile of deuterium in tungsten. Results confirm the detection of deuterium. A ˜46 μm depth profile revealed that the deuterium content decreased precipitously in the first 7 μm, and detectable amounts were observed to depths in excess of 20 μm. The large probing depth of GD-OES (up to 100s of μm) enables studies not previously accessible to the more conventional techniques for investigating deuterium retention. Of particular applicability is the use of GD-OES to measure the depth profile for experiments where high deuterium concentration in the bulk material is expected: deuterium retention in neutron irradiated materials, and ultra-high deuterium fluences in burning plasma environment.

Aircraft EMP Isolation Study.

DTIC Science & Technology

1980-07-01

the polarity indicators. Martin’s relationship describes the conditions present when flashover occurs. W. C. Crewson of Pulsar Associates, Inc...I 0 co I I II I I I L- - a’ S-- CD cm 40 S - L Cd) 00 00r 0- L- a’OI CMI 0~ >’i I C 0 u 0CJ CA 0 0 0 m. r- Lo . fl Lo V’ 41.0 r - C 09 4 J -C O O l .oC

Reaction-to-Fire of Wood Products and Other Building Materials: Part 1, Room/Corner Test Performance

Treesearch

Ondrej Grexa; Mark A. Dietenberger; Robert H. White

2012-01-01

This project researched the assessment of reaction-to-fire of common materials using the full-scale room/corner test (ISO 9705) protocol and the predictions of time to flashover using results from the bench-scale cone calorimeter test (ISO 5660-1). Using a burner protocol of 100 kW for 10 min, followed by 300 kW for 10 min and the test materials on the walls only, we...

Electrostatic Discharge Test of Multi-Junction Solar Array Coupons After Combined Space Environmental Exposures

NASA Technical Reports Server (NTRS)

Wright, Kenneth H.; Schneider, Todd; Vaughn, Jason; Hoang, Bao; Funderburk, Victor V.; Wong, Frankie; Gardiner, George

2010-01-01

A set of multi-junction GaAs/Ge solar array test coupons were subjected to a sequence of 5-year increments of combined environmental exposure tests. The test coupons capture an integrated design intended for use in a geosynchronous (GEO) space environment. A key component of this test campaign is conducting electrostatic discharge (ESD) tests in the inverted gradient mode. The protocol of the ESD tests is based on the ISO/CD 11221, the ISO standard for ESD testing on solar array panels. This standard is currently in its final review with expected approval in 2010. The test schematic in the ISO reference has been modified with Space System/Loral designed circuitry to better simulate the on-orbit operational conditions of its solar array design. Part of the modified circuitry is to simulate a solar array panel coverglass flashover discharge. All solar array coupons used in the test campaign consist of 4 cells. The ESD tests are performed at the beginning of life (BOL) and at each 5-year environment exposure point. The environmental exposure sequence consists of UV radiation, electron/proton particle radiation, thermal cycling, and ion thruster plume. This paper discusses the coverglass flashover simulation, ESD test setup, and the importance of the electrical test design in simulating the on-orbit operational conditions. Results from 5th-year testing are compared to the baseline ESD characteristics determined at the BOL condition.

Structural transformations in austenitic stainless steel induced by deuterium implantation: irradiation at 100 K.

PubMed

Morozov, Oleksandr; Zhurba, Volodymyr; Neklyudov, Ivan; Mats, Oleksandr; Rud, Aleksandr; Chernyak, Nikolay; Progolaieva, Viktoria

2015-01-01

Deuterium thermal desorption spectra were investigated on the samples of austenitic stainless steel 18Cr10NiTi preimplanted at 100 K with deuterium ions in the dose range from 3 × 10(15) to 5 × 10(18) D/cm(2). The kinetics of structural transformation development in the implantation steel layer was traced from deuterium thermodesorption spectra as a function of implanted deuterium concentration. At saturation of austenitic stainless steel 18Cr10NiTi with deuterium by means of ion implantation, structural-phase changes take place, depending on the dose of implanted deuterium. The maximum attainable concentration of deuterium in steel is C = 1 (at.D/at.met. = 1/1). The increase in the implanted dose of deuterium is accompanied by the increase in the retained deuterium content, and as soon as the deuterium concentration attains C ≈ 0.5 the process of shear martensitic structural transformation in steel takes place. It includes the formation of bands, body-centered cubic (bcc) crystal structure, and the ferromagnetic phase. Upon reaching the deuterium concentration C > 0.5, the presence of these molecules causes shear martensitic structural transformations in the steel, which include the formation of characteristic bands, bcc crystal structure, and the ferromagnetic phase. At C ≥ 0.5, two hydride phases are formed in the steel, the decay temperatures of which are 240 and 275 K. The hydride phases are formed in the bcc structure resulting from the martensitic structural transformation in steel.

Deuterium permeation behaviors in tungsten implanted with nitrogen

NASA Astrophysics Data System (ADS)

Liang, Chuan-hui; Wang, Dongping; Jin, Wei; Lou, Yuanfu; Wang, Wei; Ye, Xiaoqiu; Chen, Chang-an; Liu, Kezhao; Xu, Haiyan; Wang, Xiaoying; Kleyn, Aart W.

2018-07-01

Surface modification of tungsten due to the cooling species nitrogen seeded in the divertor region, i.e., by nitrogen ion implantation or re-deposition, is considered to affect the permeation behavior of H isotopes. This work focuses on the effect of nitrogen ion implantation into tungsten (W-N) on the deuterium gas-driven permeation behavior. For comparison, both permeation in tungsten implanted with W ion (W-W) and without implantation (pristine W) are studied. These three samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photo-electron spectroscopy (XPS). The SEM results revealed that the W-W sample has various voids on the surface, and the W-N sample has a rough surface with pretty fine microstructures. These are different from the pristine W sample with a smooth and compact surface. The XRD patterns show the disappearance of crystallinity on both W-W and W-N sample surfaces. It indicates that the ion implantation process results in an almost complete conversion from crystalline to amorphous in the sample surfaces. The sputter-depth profiling XPS spectra show that the implanted nitrogen prefers to form a 140 nm thick tungsten nitride layer. In permeation experiments, it was found that the D permeability is temperature dependent. Interestingly, the W-N sample presented a lower D permeability than the W-W sample, but higher than the pristine W sample. Such behavior implies that tungsten nitride acts as a permeation barrier, while defects created by ions implantation can promote permeability. The possible permeation mechanism correlated with sample surface composition and microstructure is consequently discussed in this work.

Deuterium separation by infrared-induced addition reaction

DOEpatents

Marling, John B.

1977-01-01

A method for deuterium enrichment by the infrared-induced addition reaction of a deuterium halide with an unsaturated aliphatic compound. A gaseous mixture of a hydrogen halide feedstock and an unsaturated aliphatic compound, particularly an olefin, is irradiated to selectively vibrationally excite the deuterium halide contained therein. The excited deuterium halide preferentially reacts with the unsaturated aliphatic compound to produce a deuterated addition product which is removed from the reaction mixture.

Desorption dynamics of deuterium in CuCrZr alloy

NASA Astrophysics Data System (ADS)

Thi Nguyen, Lan Anh; Lee, Sanghwa; Noh, S. J.; Lee, S. K.; Park, M. C.; Shu, Wataru; Pitcher, Spencer; Torcy, David; Guillermain, David; Kim, Jaeyong

2017-12-01

Desorption behavior of deuterium (D2) in CuCrZr alloy was investigated considering sample thickness, loading and baking temperature of deuterium followed by the ITER scopes. Cylindrical specimens of 1, 3, 5 mm thick with 4 mm diameter were exposed to deuterium at a pressure of 25 bar at 120, 240 and 350 °C for 24 h, then baked at 800 °C in a vacuum chamber maintained at a pressure lower than 10-7 Torr. Deuterium desorption characteristics such as desorption rate and amount of deuterium in the sample were estimated by analyzing the desorption peaks monitored with a residual gas analyzer (RGA), and the trapping energy of deuterium was calculated using thermal desorption spectroscopy (TDS). Secondary ion mass spectroscopy (SIMS) results showed that deuterium atoms embedded in the sample at a depth of less than 15 μm and desorbed as low as 400 °C. All absorbed deuterium atoms in the specimen were completely retrieved by dynamic pumping at 800 °C in 15 min. The desorption rate of deuterium per unit area was inversely proportional to the increment of the thickness of the sample, and was proportional to the loading temperature. Based on the assumption that a uniform distribution of interstitial sites for deuterium follows the Femi-Dirac statistics, the result of TDS demonstrated that the CuCrZr alloy has two types of trapping energies, which were estimated to be 62 and 79 kJ/mol.

Hydrogen/deuterium exchange studies of native rabbit MM-CK dynamics.

PubMed

Mazon, Hortense; Marcillat, Olivier; Forest, Eric; Vial, Christian

2004-02-01

Creatine kinase (CK) isoenzymes catalyse the reversible transfer of a phosphoryl group from ATP onto creatine. This reaction plays a very important role in the regulation of intracellular ATP concentrations in excitable tissues. CK isoenzymes are highly resistant to proteases in native conditions. To appreciate localized backbone dynamics, kinetics of amide hydrogen exchange with deuterium was measured by pulse-labeling the dimeric cytosolic muscle CK isoenzyme. Upon exchange, the protein was digested with pepsin, and the deuterium content of the resulting peptides was determined by liquid chromatography coupled to mass spectrometry (MS). The deuteration kinetics of 47 peptides identified by MS/MS and covering 96% of the CK backbone were analyzed. Four deuteration patterns have been recognized: The less deuterated peptides are located in the saddle-shaped core of CK, whereas most of the highly deuterated peptides are close to the surface and located around the entrance to the active site. Their exchange kinetics are discussed by comparison with the known secondary and tertiary structures of CK with the goal to reveal the conformational dynamics of the protein. Some of the observed dynamic motions may be linked to the conformational changes associated with substrate binding and catalytic mechanism.

Filamentation in the pinched column of the dense plasma focus

NASA Astrophysics Data System (ADS)

Kubes, P.; Paduch, M.; Cikhardt, J.; Cikhardtova, B.; Klir, D.; Kravarik, J.; Rezac, K.; Zielinska, E.; Sadowski, M. J.; Szymaszek, A.; Tomaszewski, K.; Zaloga, D.

2017-03-01

The paper describes the filamentary structure observed in the high-energy ultraviolet radiation for discharges performed at the hydrogen- or deuterium-filling and at the puffing of hydrogen, deuterium or helium, in a mega-ampere dense plasma-focus facility. The lifetime of this structure overcomes 50 ns. These filaments connect the surface of a pinched column with internal plasmoids formed at different combinations of filling and puffing gases and they should transport some current and plasma. During all the investigated deuterium shots, the fusion-produced neutrons were recorded. Therefore, deuterons should be present in the region of their acceleration, independent of the applied puffing of the gas. Simultaneously with the observed filaments, inside the dense plasma column small plasma-balls of mm-dimensions were observed, which had a similar lifetime (longer than the relaxation time) and quasi-stationary positions in the discharge volume. The observed filaments and balls might be a manifestation of the (i) discrete spatial structure of the current flowing through and around the dense plasma column and (ii) transport of the plasma from external layers to the central region. Their formation and visualization were easier due to the application of air admixtures in the puffed gas.

Baseline study of Oxygen 18 and deuterium in the Roswell, New Mexico, groundwater basin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoy, R.N.; Gross, G.W.

The isotopic ratios of deuterium and oxygen 18 were measured in precipitation, surface, and ground water samples from the Roswell Artesian ground water basin in south-central New Mexico. The narrow range of D and 180 indicates mixing effects which are ascribed to one or more of the following factors: long ground water flow paths; large temperature fluctuations affecting which overwhelm the influence of elevation on precipitation; two sources of atmospheric moisture; interaquifer leakage; and recharge from intermittent streams with the flow-length expanding and contracting over large distances. It is concluded that a more precise definition of circulation patterns on themore » basis of stable isotope differences will require a much greater sampling frequency in both space and time.« less

Interpretation of rotation and momentum transport in the DIII-D edge plasma and comparison with neoclassical theory

DOE PAGES

Stacey, Weston M.; Grierson, Brian A.

2014-05-08

Here, a low-confinement mode discharge which optimizes the capability of the new main-ion chargeexchange-recombination spectroscopy system on DIII-D to measure deuterium toroidal velocity is interpretted in comparison with the predictions of neoclassical theory, with an emphasis on the plasma edge region. The observed peaking in the deuterium toroidal velocity near the separatrix is shown to be consistent with intrinsic co-rotation due to ion orbit loss. In general, the standard neoclassical toroidal and poloidal momentum transport rates are found to be smaller than those inferred from experiment, but a comparison has not yet been made with the more recent extended neoclassicalmore » theory that calculates the effects of poloidal asymmetries using an elongated flux surface representation.« less

Deuterium content of water increases depression susceptibility: the potential role of a serotonin-related mechanism.

PubMed

Strekalova, Tatyana; Evans, Matthew; Chernopiatko, Anton; Couch, Yvonne; Costa-Nunes, João; Cespuglio, Raymond; Chesson, Lesley; Vignisse, Julie; Steinbusch, Harry W; Anthony, Daniel C; Pomytkin, Igor; Lesch, Klaus-Peter

2015-01-15

Environmental factors can significantly affect disease prevalence, including neuropsychiatric disorders such as depression. The ratio of deuterium to protium in water shows substantial geographical variation, which could affect disease susceptibility. Thus the link between deuterium content of water and depression was investigated, both epidemiologically, and in a mouse model of chronic mild stress. We performed a correlation analysis between deuterium content of tap water and rates of depression in regions of the USA. Next, we used a 10-day chronic stress paradigm to test whether 2-week deuterium-depleted water treatment (91 ppm) affects depressive-like behavior and hippocampal SERT. The effect of deuterium-depletion on sleep electrophysiology was also evaluated in naïve mice. There was a geographic correlation between a content of deuterium and the prevalence of depression across the USA. In the chronic stress model, depressive-like features were reduced in mice fed with deuterium-depleted water, and SERT expression was decreased in mice treated with deuterium-treated water compared with regular water. Five days of predator stress also suppressed proliferation in the dentate gyrus; this effect was attenuated in mice fed with deuterium-depleted water. Finally, in naïve mice, deuterium-depleted water treatment increased EEG indices of wakefulness, and decreased duration of REM sleep, phenomena that have been shown to result from the administration of selective serotonin reuptake inhibitors (SSRI). Our data suggest that the deuterium content of water may influence the incidence of affective disorder-related pathophysiology and major depression, which might be mediated by the serotoninergic mechanisms. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

On the deuterium abundance and the importance of stellar mass loss in the interstellar and intergalactic medium

NASA Astrophysics Data System (ADS)

van de Voort, Freeke; Quataert, Eliot; Faucher-Giguère, Claude-André; Kereš, Dušan; Hopkins, Philip F.; Chan, T. K.; Feldmann, Robert; Hafen, Zachary

2018-06-01

We quantify the gas-phase abundance of deuterium and fractional contribution of stellar mass loss to the gas in cosmological zoom-in simulations from the Feedback In Realistic Environments project. At low metallicity, our simulations confirm that the deuterium abundance is very close to the primordial value. The chemical evolution of the deuterium abundance that we derive here agrees quantitatively with analytical chemical evolution models. We furthermore find that the relation between the deuterium and oxygen abundance exhibits very little scatter. We compare our simulations to existing high-redshift observations in order to determine a primordial deuterium fraction of (2.549 ± 0.033) × 10-5 and stress that future observations at higher metallicity can also be used to constrain this value. At fixed metallicity, the deuterium fraction decreases slightly with decreasing redshift, due to the increased importance of mass-loss from intermediate-mass stars. We find that the evolution of the average deuterium fraction in a galaxy correlates with its star formation history. Our simulations are consistent with observations of the Milky Way's interstellar medium (ISM): the deuterium fraction at the solar circle is 85-92 per cent of the primordial deuterium fraction. We use our simulations to make predictions for future observations. In particular, the deuterium abundance is lower at smaller galactocentric radii and in higher mass galaxies, showing that stellar mass loss is more important for fuelling star formation in these regimes (and can even dominate). Gas accreting on to galaxies has a deuterium fraction above that of the galaxies' ISM, but below the primordial fraction, because it is a mix of gas accreting from the intergalactic medium and gas previously ejected or stripped from galaxies.

Groundwater Recharge Processes Revealed By Multi-Tracers Approach in a Headwater, North China Plain

NASA Astrophysics Data System (ADS)

Sakakibara, K.; Tsujimura, M.; Song, X.; Zhang, J.

2014-12-01

Groundwater recharge variation in space and time is crucial for effective water management especially in arid/ semi-arid regions. In order to reveal comprehensive groundwater recharge processes in a catchment with a large topographical relief and seasonal hydrological variations, intensive field surveys were conducted at 4 times in different seasons in Wangkuai watershed, Taihang Mountains, which is a main groundwater recharge zone of North China Plain. The groundwater, spring, stream water and lake water were sampled, and inorganic solute constituents and stable isotopes of oxygen-18 and deuterium were determined on all water samples. Also, the stream flow rate was observed in stable state condition. The stable isotopic compositions, silica and bicarbonate concentrations in the groundwater show close values as those in the surface water, suggesting main groundwater recharge occurs from surface water at mountain-plain transitional zone throughout a year. Also, the deuterium and oxgen-18 in the Wangkuai reservoir and the groundwater in the vicinity of the reservoir show higher values, suggesting the reservoir water, affected by evaporation effect, seems to have an important role for the groundwater recharge in alluvial plain. For specifying the groundwater recharge area and quantifying groundwater recharge rate from the reservoir, an inversion analysis and a simple mixing model were applied in Wangkuai watershed using stable isotopes of oxygen-18 and deuterium. The model results show that groundwater recharge occurs dominantly at the altitude from 357 m to 738 m corresponding to mountain-plain transitional zone, and groundwater recharge rate by Wangkuai reservoir is estimated to be 2.4 % of total groundwater recharge in Wangkuai watershed.

Modelling deuterium release from tungsten after high flux high temperature deuterium plasma exposure

NASA Astrophysics Data System (ADS)

Grigorev, Petr; Matveev, Dmitry; Bakaeva, Anastasiia; Terentyev, Dmitry; Zhurkin, Evgeny E.; Van Oost, Guido; Noterdaeme, Jean-Marie

2016-12-01

Tungsten is a primary candidate for plasma facing materials for future fusion devices. An important safety concern in the design of plasma facing components is the retention of hydrogen isotopes. Available experimental data is vast and scattered, and a consistent physical model of retention of hydrogen isotopes in tungsten is still missing. In this work we propose a model of non-equilibrium hydrogen isotopes trapping under fusion relevant plasma exposure conditions. The model is coupled to a diffusion-trapping simulation tool and is used to interpret recent experiments involving high plasma flux exposures. From the computational analysis performed, it is concluded that high flux high temperature exposures (T = 1000 K, flux = 1024 D/m2/s and fluence of 1026 D/m2) result in generation of sub-surface damage and bulk diffusion, so that the retention is driven by both sub-surface plasma-induced defects (bubbles) and trapping at natural defects. On the basis of the non-equilibrium trapping model we have estimated the amount of H stored in the sub-surface region to be ∼10-5 at-1, while the bulk retention is about 4 × 10-7 at-1, calculated by assuming the sub-surface layer thickness of about 10 μm and adjusting the trap concentration to comply with the experimental results for the integral retention.

Proposal for New Experimental Tests of the Bose-Einstein Condensation Mechanism for Low-Energy Nuclear Reaction and Transmutation Processes in Deuterium Loaded - and Nano-Scale Cavities

NASA Astrophysics Data System (ADS)

Kim, Yeong E.; Koltick, David S.; Reifenberger, Ronald G.; Zubarev, Alexander L.

2006-02-01

Most of experimental results of low-energy nuclear reaction (LENR) reported so far cannot be reproduced on demand. There have been persistent experimental results indicating that the LENR and transmutation processes in condensed matters (LENRTPCM) are surface phenomena rather than bulk phenomena. Recently proposed Bose-Einstein condensation (BEC) mechanism may provide a suitable theoretical description of the surface phenomena. New experiments are proposed and described for testing the BEC mechanism for LENR and transmutation processes in micro- and nano-scale traps. (1) We propose the use of micro- or nano-porous conducting materials as a cathode in electrolysis experiments with heavy water with or without Li in order to stabilize the active surface spots and to enhance the effect for the purpose of improving the reproducibility of excess heat generation and nuclear emission. (2) We propose new experimental tests of the BEC mechanism by measuring the pressure and temperature dependence of LENR events using deuterium gas and these deuterated metals with or without Li. If the LENRTPCM are surface phenomena, the proposed use of micro-/nano-scale porous materials is expected to enhance and scale up the LENRTPCM effects by many order of magnitude, and thus may lead to better reproductivity and theoretical understanding of the phenomena.

Characterization of deuterium clusters mixed with helium gas for an application in beam-target-fusion experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bang, W.; Quevedo, H. J.; Bernstein, A. C.

We measured the average deuterium cluster size within a mixture of deuterium clusters and helium gas by detecting Rayleigh scattering signals. The average cluster size from the gas mixture was comparable to that from a pure deuterium gas when the total backing pressure and temperature of the gas mixture were the same as those of the pure deuterium gas. According to these measurements, the average size of deuterium clusters depends on the total pressure and not the partial pressure of deuterium in the gas mixture. To characterize the cluster source size further, a Faraday cup was used to measure themore » average kinetic energy of the ions resulting from Coulomb explosion of deuterium clusters upon irradiation by an intense ultrashort pulse. The deuterium ions indeed acquired a similar amount of energy from the mixture target, corroborating our measurements of the average cluster size. As the addition of helium atoms did not reduce the resulting ion kinetic energies, the reported results confirm the utility of using a known cluster source for beam-target-fusion experiments by introducing a secondary target gas.« less

Characterization of deuterium clusters mixed with helium gas for an application in beam-target-fusion experiments

DOE PAGES

Bang, W.; Quevedo, H. J.; Bernstein, A. C.; ...

2014-12-10

We measured the average deuterium cluster size within a mixture of deuterium clusters and helium gas by detecting Rayleigh scattering signals. The average cluster size from the gas mixture was comparable to that from a pure deuterium gas when the total backing pressure and temperature of the gas mixture were the same as those of the pure deuterium gas. According to these measurements, the average size of deuterium clusters depends on the total pressure and not the partial pressure of deuterium in the gas mixture. To characterize the cluster source size further, a Faraday cup was used to measure themore » average kinetic energy of the ions resulting from Coulomb explosion of deuterium clusters upon irradiation by an intense ultrashort pulse. The deuterium ions indeed acquired a similar amount of energy from the mixture target, corroborating our measurements of the average cluster size. As the addition of helium atoms did not reduce the resulting ion kinetic energies, the reported results confirm the utility of using a known cluster source for beam-target-fusion experiments by introducing a secondary target gas.« less

Small system for tritium accelerator mass spectrometry

DOEpatents

Roberts, M.L.; Davis, J.C.

1993-02-23

Apparatus for ionizing and accelerating a sample containing isotopes of hydrogen and detecting the ratios of hydrogen isotopes contained in the sample is disclosed. An ion source generates a substantially linear ion beam including ions of tritium from the sample. A radio-frequency quadrupole accelerator is directly coupled to and axially aligned with the source at an angle of substantially zero degrees. The accelerator accelerates species of the sample having different mass to different energy levels along the same axis as the ion beam. A spectrometer is used to detect the concentration of tritium ions in the sample. In one form of the invention, an energy loss spectrometer is used which includes a foil to block the passage of hydrogen, deuterium and [sup 3]He ions, and a surface barrier or scintillation detector to detect the concentration of tritium ions. In another form of the invention, a combined momentum/energy loss spectrometer is used which includes a magnet to separate the ion beams, with Faraday cups to measure the hydrogen and deuterium and a surface barrier or scintillation detector for the tritium ions.

Small system for tritium accelerator mass spectrometry

DOEpatents

Roberts, Mark L.; Davis, Jay C.

1993-01-01

Apparatus for ionizing and accelerating a sample containing isotopes of hydrogen and detecting the ratios of hydrogen isotopes contained in the sample is disclosed. An ion source generates a substantially linear ion beam including ions of tritium from the sample. A radio-frequency quadrupole accelerator is directly coupled to and axially aligned with the source at an angle of substantially zero degrees. The accelerator accelerates species of the sample having different mass to different energy levels along the same axis as the ion beam. A spectrometer is used to detect the concentration of tritium ions in the sample. In one form of the invention, an energy loss spectrometer is used which includes a foil to block the passage of hydrogen, deuterium and .sup.3 He ions, and a surface barrier or scintillation detector to detect the concentration of tritium ions. In another form of the invention, a combined momentum/energy loss spectrometer is used which includes a magnet to separate the ion beams, with Faraday cups to measure the hydrogen and deuterium and a surface barrier or scintillation detector for the tritium ions.

An in situ accelerator-based diagnostic for plasma-material interactions science on magnetic fusion devices.

PubMed

Hartwig, Zachary S; Barnard, Harold S; Lanza, Richard C; Sorbom, Brandon N; Stahle, Peter W; Whyte, Dennis G

2013-12-01

This paper presents a novel particle accelerator-based diagnostic that nondestructively measures the evolution of material surface compositions inside magnetic fusion devices. The diagnostic's purpose is to contribute to an integrated understanding of plasma-material interactions in magnetic fusion, which is severely hindered by a dearth of in situ material surface diagnosis. The diagnostic aims to remotely generate isotopic concentration maps on a plasma shot-to-shot timescale that cover a large fraction of the plasma-facing surface inside of a magnetic fusion device without the need for vacuum breaks or physical access to the material surfaces. Our instrument uses a compact (~1 m), high-current (~1 milliamp) radio-frequency quadrupole accelerator to inject 0.9 MeV deuterons into the Alcator C-Mod tokamak at MIT. We control the tokamak magnetic fields--in between plasma shots--to steer the deuterons to material surfaces where the deuterons cause high-Q nuclear reactions with low-Z isotopes ~5 μm into the material. The induced neutrons and gamma rays are measured with scintillation detectors; energy spectra analysis provides quantitative reconstruction of surface compositions. An overview of the diagnostic technique, known as accelerator-based in situ materials surveillance (AIMS), and the first AIMS diagnostic on the Alcator C-Mod tokamak is given. Experimental validation is shown to demonstrate that an optimized deuteron beam is injected into the tokamak, that low-Z isotopes such as deuterium and boron can be quantified on the material surfaces, and that magnetic steering provides access to different measurement locations. The first AIMS analysis, which measures the relative change in deuterium at a single surface location at the end of the Alcator C-Mod FY2012 plasma campaign, is also presented.

Investigation of Optically Induced Avalanching in GaAs

DTIC Science & Technology

1989-06-01

by Bovino , et al 4 to increase the hold off voltage. The button switch design of Fig. 4c has been used by several researchers5 ’ 7 to obtain the...ul Long flashover palh Figure 3b. 434 Optical Jlatlern a. Mourou Switch b. Bovino Switch c. Button Switch Figure 4. Photoconductive Switches...Technology and Devices Laboratory, ERADCOM (by L. Bovino , et. all) 4 • The deposition recipe for the contacts is 1) 50 ANi (provides contact to GaAs

Impulse Flashover Tests at Edgar Beauchamp High Voltage Test Facility, Dixon, California, in Support of Cutler Insulator Failure Investigation

DTIC Science & Technology

2006-07-01

sites. The strength member of the safety core insulators is a fiberglass belt wrapped around pins in the end fittings. Porcelain tubes cover the belt... porcelain tube and heavily tracked the fiberglass belt but left the belt intact structurally (Figure 1). Figure 1. Cutler safety core insulator ...fail-safe insulators . For these tests, the porcelain tube of the safety core insulator was replaced with a plastic see-through tube. The test report [5

Applicability of the “Gallet equation” to the vegetation clearances of NERC Reliability Standard FAC-003-2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kirkham, Harold

2012-03-31

NERC has proposed a standard to use to specify clearances between vegetation and power lines. The purpose of the rule is to reduce the probability of flashover to a calculably low level. This report was commissioned by FERC’s Office of Electrical Reliability. The scope of the study was analysis of the mathematics and documentation of the technical justification behind the application of the Gallet equation and the assumptions used in the technical reference paper

Advanced Radiation Theory Support Annual Report 2003, Final Report

DTIC Science & Technology

2004-04-19

diameter wires would lose a higher mass fraction. Table 2. Energy Transfers for Ti Loads Dia. & Case H 2 H13 Mass -a-m Z,DE kJ kJ Pg 1000 - Z 428.2...issues covered are (1) issues and directions for future research, (2) zero- and one-dimensional modeling of DQ experiments, (3) enhanced energy ...coupling and x-ray emission in z-pinch implosions, (4) confinement and compression of magnetic flux by plasma shells, and (6) flashover and energy coupling

Ultra-Compact Accelerator Technologies for Application in Nuclear Techniques

NASA Astrophysics Data System (ADS)

Sampayan, S.; Caporaso, G.; Chen, Y.-J.; Carazo, V.; Falabella, S.; Guethlein, G.; Guse, S.; Harris, J. R.; Hawkins, S.; Holmes, C.; Krogh, M.; Nelson, S.; Paul, A. C.; Pearson, D.; Poole, B.; Schmidt, R.; Sanders, D.; Selenes, K.; Sitaraman, S.; Sullivan, J.; Wang, L.; Watson, J.

2009-12-01

We report on compact accelerator technology development for potential use as a pulsed neutron source quantitative post verifier. The technology is derived from our on-going compact accelerator technology development program for radiography under the US Department of Energy and for a clinic sized compact proton therapy systems under an industry sponsored Cooperative Research and Development Agreement. The accelerator technique relies on the synchronous discharge of a prompt pulse generating stacked transmission line structure with the beam transit. The goal of this technology is to achieve ˜10 MV/m gradients for 10 s of nanoseconds pulses and ˜100 MV/m gradients for ˜1 ns systems. As a post verifier for supplementing existing x-ray equipment, this system can remain in a charged, stand-by state with little or no energy consumption. We describe the progress of our overall component development effort with the multilayer dielectric wall insulators (i.e., the accelerator wall), compact power supply technology, kHz repetition-rate surface flashover ion sources, and the prompt pulse generation system consisting of wide-bandgap switches and high performance dielectric materials.

Plasma puff initiation of high Coulomb transfer switches

NASA Technical Reports Server (NTRS)

Venable, D. D.; Choi, E. H.

1990-01-01

The plasma-puff triggering mechanism based on a hypocycloidal pinch geometry was investigated to determine the optimal operating conditions for the azimuthally uniform surface flashover which initiates plasma-puff under wide range of fill gas pressure of Ar, He and N2. The optimal fill gas pressure for the azimuthally uniform plasma-puff was about 120 mTorr and 450 Torr for He and N2, and between 120 mTorr and 5 Torr for Ar. The inverse pinch switch was triggered with the plasma-puff and the switching capability under various electrical parameters and working gas pressures of Ar, He and N2 was determined. It was also shown that the azimuthally uniform switching discharges were dependent on the type of fill gas and its fill pressure. A new concept of plasma-focus driven plasma-puff was also discussed in comparison with the hypocycloidal pinch plasma-puff triggering. The main discharge of inverse pinch switch with plasma-focus driven plasma-puff trigger is found to be more azimuthally uniform than that with hypocycloidal pinch plasma-puff trigger in a gas pressure region between 80 mTorr and 1 Torr.

Quantum tunneling observed without its characteristic large kinetic isotope effects.

PubMed

Hama, Tetsuya; Ueta, Hirokazu; Kouchi, Akira; Watanabe, Naoki

2015-06-16

Classical transition-state theory is fundamental to describing chemical kinetics; however, quantum tunneling is also important in explaining the unexpectedly large reaction efficiencies observed in many chemical systems. Tunneling is often indicated by anomalously large kinetic isotope effects (KIEs), because a particle's ability to tunnel decreases significantly with its increasing mass. Here we experimentally demonstrate that cold hydrogen (H) and deuterium (D) atoms can add to solid benzene by tunneling; however, the observed H/D KIE was very small (1-1.5) despite the large intrinsic H/D KIE of tunneling (≳ 100). This strong reduction is due to the chemical kinetics being controlled not by tunneling but by the surface diffusion of the H/D atoms, a process not greatly affected by the isotope type. Because tunneling need not be accompanied by a large KIE in surface and interfacial chemical systems, it might be overlooked in other systems such as aerosols or enzymes. Our results suggest that surface tunneling reactions on interstellar dust may contribute to the deuteration of interstellar aromatic and aliphatic hydrocarbons, which could represent a major source of the deuterium enrichment observed in carbonaceous meteorites and interplanetary dust particles. These findings could improve our understanding of interstellar physicochemical processes, including those during the formation of the solar system.

Quantum tunneling observed without its characteristic large kinetic isotope effects

PubMed Central

Hama, Tetsuya; Ueta, Hirokazu; Kouchi, Akira; Watanabe, Naoki

2015-01-01

Classical transition-state theory is fundamental to describing chemical kinetics; however, quantum tunneling is also important in explaining the unexpectedly large reaction efficiencies observed in many chemical systems. Tunneling is often indicated by anomalously large kinetic isotope effects (KIEs), because a particle’s ability to tunnel decreases significantly with its increasing mass. Here we experimentally demonstrate that cold hydrogen (H) and deuterium (D) atoms can add to solid benzene by tunneling; however, the observed H/D KIE was very small (1–1.5) despite the large intrinsic H/D KIE of tunneling (≳100). This strong reduction is due to the chemical kinetics being controlled not by tunneling but by the surface diffusion of the H/D atoms, a process not greatly affected by the isotope type. Because tunneling need not be accompanied by a large KIE in surface and interfacial chemical systems, it might be overlooked in other systems such as aerosols or enzymes. Our results suggest that surface tunneling reactions on interstellar dust may contribute to the deuteration of interstellar aromatic and aliphatic hydrocarbons, which could represent a major source of the deuterium enrichment observed in carbonaceous meteorites and interplanetary dust particles. These findings could improve our understanding of interstellar physicochemical processes, including those during the formation of the solar system. PMID:26034285

Effects of local defect growth in direct-drive cryogenic implosions on OMEGA

NASA Astrophysics Data System (ADS)

Igumenshchev, I. V.; Goncharov, V. N.; Shmayda, W. T.; Harding, D. R.; Sangster, T. C.; Meyerhofer, D. D.

2013-08-01

Spherically symmetric, low-adiabat (adiabat α ≲ 3) cryogenic direct-drive-implosion experiments on the OMEGA laser [T. R. Boehly et al., Opt. Commun. 133, 495 (1995)] yield less than 10% of the neutrons predicted in one-dimensional hydrodynamic simulations. Two-dimensional hydrodynamic simulations suggest that this performance degradation can be explained assuming perturbations from isolated defects of submicron to tens-of-micron scale on the outer surface or inside the shell of implosion targets. These defects develop during the cryogenic filling process and typically number from several tens up to hundreds for each target covering from about 0.2% to 1% of its surface. The simulations predict that such defects can significantly perturb the implosion and result in the injection of about 1 to 2 μg of the hot ablator (carbon-deuterium) and fuel (deuterium-tritium) materials from the ablation surface into the targets. Both the hot mass injection and perturbations of the shell reduce the final shell convergence ratio and implosion performance. The injected carbon ions radiatively cool the hot spot, reducing the fuel temperature, and further reducing the neutron yield. The negative effect of local defects can be minimized by decreasing the number and size of these defects and/or using more hydrodynamically stable implosion designs with higher shell adiabat.

Deuterium enrichment by selective photo-induced dissociation of an organic carbonyl compound

DOEpatents

Marling, John B.

1981-01-01

A method for producing a deuterium enriched material by photoinduced dissociation which uses as the working material a gas phase photolytically dissociable organic carbonyl compound containing at least one hydrogen atom bonded to an atom which is adjacent to a carbonyl group and consisting of molecules wherein said hydrogen atom is present as deuterium and molecules wherein said hydrogen atom is present as another isotope of hydrogen. The organic carbonyl compound is subjected to intense infrared radiation at a preselected wavelength to selectively excite and thereby induce dissociation of the deuterium containing species to yield a deuterium enriched stable molecular product. Undissociated carbonyl compound, depleted in deuterium, is preferably redeuterated for reuse.

Direct depth distribution measurement of deuterium in bulk tungsten exposed to high-flux plasma

DOE PAGES

Taylor, Chase N.; Shimada, M.

2017-05-08

Understanding tritium retention and permeation in plasma-facing components is critical for fusion safety and fuel cycle control. Glow discharge optical emission spectroscopy (GD-OES) is shown to be an effective tool to reveal the depth profile of deuterium in tungsten. Results confirm the detection of deuterium. Furthermore, a ~46 µm depth profile revealed that the deuterium content decreased precipitously in the first 7 µm, and detectable amounts were observed to depths in excess of 20 µm. The large probing depth of GD-OES (up to 100s of µm) enables studies not previously accessible to the more conventional techniques for investigating deuterium retention.more » Of particular applicability is the use of GD-OES to measure the depth profile for experiments where high diffusion is expected: deuterium retention in neutron irradiated materials, and ultra-high deuterium fluences in burning plasma environment.« less

Effects of chemical states of carbon on deuterium retention in carbon-containing materials

NASA Astrophysics Data System (ADS)

Oyaidzu, Makoto; Kimura, Hiromi; Nakahata, Toshihiko; Nishikawa, Yusuke; Tokitani, Masayuki; Oya, Yasuhisa; Iwakiri, Hirotomo; Yoshida, Naoaki; Okuno, Kenji

2007-08-01

Deuterium retention behavior in highly oriented pyrolytic graphite (HOPG), poly-crystalline diamond, poly-crystalline SiC, sintered WC, and converted B 4C were investigated to reveal tritium behavior in re-deposition and co-deposition layers. Such layers would contain carbon, when the first wall and/or divertor were made of graphite or carbon-containing materials. Furthermore, the employment of other materials such as tungsten, and first wall conditioning such as boronization would complicate the layers. No different deuterium trapping sites due to carbon from those in HOPG were found in all the samples, where two deuterium trapping processes were observed: hot atom chemical trapping of energetic deuterium by a dangling bond of carbon and thermochemical trapping of thermalized deuterium in a constituent atom vacancy surrounded by carbons. Additionally, the latter reaction could be easily counteracted by or competed with the other deuterium trapping reactions by constituent atoms.

Deuterium gas-driven permeation and subsequent retention in rolled tungsten foils

NASA Astrophysics Data System (ADS)

Liu, Feng; Zhou, Haishan; Li, Xiao-Chun; Xu, Yuping; An, Zhongqing; Mao, Hongmin; Xing, Wenjing; Hou, Qing; Luo, Guang-Nan

2014-12-01

Experiments concerning deuterium gas-driven permeation through rolled tungsten foils in the temperature range of 850-950 K and subsequent deuterium retention have been performed. The steady state permeation flux of deuterium is proportional to the square root of the driving pressure. The permeability of deuterium is in an order of 10-14 mol m-1 s-1 Pa-1/2 in this temperature range and the activation energy for permeation is 1.21 eV. Measurements of diffusivity are significantly affected by the driving pressure, which can be well explained by a saturable-trap model. Thermal desorption spectra of samples feature a single deuterium release peak at about 873 K. TMAP 4 modeling of this peak gives a detrapping energy of 1.70 eV, which fits the dissociation enthalpy of deuterium desorbing from the inner wall of vacancy clusters or pores in tungsten.

Effects of lithium-implantation on the hydrogen retention in both a-C:H and a-SiC:H materials submitted to deuterium bombardment

NASA Astrophysics Data System (ADS)

Barbier, G.; Ross, G. G.; El Khakani, M. A.; Chevarier, N.; Chevarier, A.

1997-02-01

The hydrogen release in plasma facing materials is a challenging problem for the hydrogen recycling. The hydrogen desorption from the a-C:H and a-SiC:H materials induced by deuterium bombardment has been investigated. Prior to the deuterium bombardment, both materials were implanted with different fluences of lithium ions. Before and after each irradiation, depth profiles of H, Li and deuterium were determined by nuclear microanalysis. After deuterium bombardment, it is shown that the retention of the initial hydrogen in both materials was enhanced by increasing the total dose of the implanted Li. For the a-C:H samples, the hydrogen desorption under deuterium bombardment was strongly reduced by lithium implantation. This effect was also evidenced in a-SiC:H samples, even though it is less spectacular than in a-C:H. Also, nuclear analyses showed that the retained dose of deuterium decreases when the lithium concentration increases. This could be a result of the formation of LiH bonds which occurs to the detriment of deuterium retention in both a-C:H and a-SiC:H materials. Preliminary results of both materials exposed to TdeV tokamak discharges confirms the role of Li in hydrogen retention, already observed in deuterium bombardment exposure.

Ignition of a Deuterium Micro-Detonation with a Gigavolt Super Marx Generator

NASA Astrophysics Data System (ADS)

Winterberg, Friedwardt

2009-09-01

The Centurion-Halite experiment demonstrated the feasibility of igniting a deuterium-tritium micro-explosion with an energy of not more than a few megajoule, and the Mike test, the feasibility of a pure deuterium explosion with an energy of more than 106 MJ. In both cases the ignition energy was supplied by a fission bomb explosive. While an energy of a few megajoule, to be released in the time required of less than 10-9 s, can be supplied by lasers and intense particle beams, this is not enough to ignite a pure deuterium explosion. Because the deuterium-tritium reaction depends on the availability of lithium, the non-fission ignition of a pure deuterium fusion reaction would be highly desirable. It is shown that this goal can conceivably be reached with a "Super Marx Generator", where a large number of "ordinary" Marx generators charge (magnetically insulated) fast high voltage capacitors of a second stage Marx generator, called a "Super Marx Generator", ultimately reaching gigavolt potentials with an energy output in excess of 100 MJ. An intense 107 Ampere-GeV proton beam drawn from a "Super Marx Generator" can ignite a deuterium thermonuclear detonation wave in a compressed deuterium cylinder, where the strong magnetic field of the proton beam entraps the charged fusion reaction products inside the cylinder. In solving the stand-off problem, the stiffness of a GeV proton beam permits to place the deuterium target at a comparatively large distance from the wall of a cavity confining the deuterium micro-explosion.

Characterization of a deuterium-deuterium plasma fusion neutron generator

NASA Astrophysics Data System (ADS)

Lang, R. F.; Pienaar, J.; Hogenbirk, E.; Masson, D.; Nolte, R.; Zimbal, A.; Röttger, S.; Benabderrahmane, M. L.; Bruno, G.

2018-01-01

We characterize the neutron output of a deuterium-deuterium plasma fusion neutron generator, model 35-DD-W-S, manufactured by NSD/Gradel-Fusion. The measured energy spectrum is found to be dominated by neutron peaks at 2.2 MeV and 2.7 MeV. A detailed GEANT4 simulation accurately reproduces the measured energy spectrum and confirms our understanding of the fusion process in this generator. Additionally, a contribution of 14 . 1 MeV neutrons from deuterium-tritium fusion is found at a level of 3 . 5%, from tritium produced in previous deuterium-deuterium reactions. We have measured both the absolute neutron flux as well as its relative variation on the operational parameters of the generator. We find the flux to be proportional to voltage V 3 . 32 ± 0 . 14 and current I 0 . 97 ± 0 . 01. Further, we have measured the angular dependence of the neutron emission with respect to the polar angle. We conclude that it is well described by isotropic production of neutrons within the cathode field cage.

Deuterium-lithium plasma as a source of fusion neutrons

NASA Astrophysics Data System (ADS)

Chirkov, A. Yu; Vesnin, V. R.

2017-11-01

The concepts of deuterium-tritium (D-T) fusion neutron source are currently developed for hybrid fusion-fission systems and the waste transmutation ones. The need to use tritium technologies is a deterrent factor in this promising direction of energy production. Potential possibilities of using systems that do not require tritium developments are of a significant interest. A deuterium-deuterium (D-D) reaction is considered for the use in demonstration fusion neutron sources. The product of this reaction is tritium, which will burn in the plasma with the emission of fast neutrons. D-D reaction is significantly slower then D-T reaction. Present study shows an increase in neutron yield using a powerful injection of the beam of deuterium atoms. The reactions of the deuterium with lithium isotopes are considered. In some of these reactions, fast neutrons can be obtained. The results of the calculation of the neutron yield from the deuterium lithium plasma are discussed. The estimates of the parameters needed for the realization of a source of fusion neutrons are presented.

Structure, Dynamics, and Deuterium Fractionation of Massive Pre-stellar Cores

NASA Astrophysics Data System (ADS)

Goodson, Matthew D.; Kong, Shuo; Tan, Jonathan C.; Heitsch, Fabian; Caselli, Paola

2016-12-01

High levels of deuterium fraction in N2H+ are observed in some pre-stellar cores. Single-zone chemical models find that the timescale required to reach observed values ({D}{frac}{{{N}}2{{{H}}}+}\\equiv {{{N}}}2{{{D}}}+/{{{N}}}2{{{H}}}+≳ 0.1) is longer than the free-fall time, possibly 10 times longer. Here, we explore the deuteration of turbulent, magnetized cores with 3D magnetohydrodynamics simulations. We use an approximate chemical model to follow the growth in abundances of N2H+ and N2D+. We then examine the dynamics of the core using each tracer for comparison to observations. We find that the velocity dispersion of the core as traced by N2D+ appears slightly sub-virial compared to predictions of the Turbulent Core Model of McKee & Tan, except at late times just before the onset of protostar formation. By varying the initial mass surface density, the magnetic energy, the chemical age, and the ortho-to-para ratio of H2, we also determine the physical and temporal properties required for high deuteration. We find that low initial ortho-to-para ratios (≲ 0.01) and/or multiple free-fall times (≳ 3) of prior chemical evolution are necessary to reach the observed values of deuterium fraction in pre-stellar cores.

Isotopic separation of snowmelt runoff during an artificial rain-on-snow event

NASA Astrophysics Data System (ADS)

Juras, Roman; Pavlasek, Jirka; Šanda, Martin; Jankovec, Jakub; Linda, Miloslav

2013-04-01

Rain-on-snow events are common phenomenon in the climate conditions of central Europe, mainly during the spring snowmelt period. These events can cause serious floods in areas with seasonal snow. The snowpack hit by rain is able to store a fraction of rain water, but runoff caused by additional snowmelt also increases. Assessment of the rainwater ratio contributing to the outflow from the snowpack is therefore critical for discharge modelling. A rainfall simulator and water enriched by deuterium were used for the study of rainwater behaviour during an artificial rain-on-snow event. An area of 1 m2 of the snow sample, which was 1.2 m deep, consisting of ripped coarse-grained snow, was sprayed during the experiment with deuterium enriched water. The outflow from the snowpack was measured and samples of outflow water were collected. The isotopic content of deuterium was further analyzed from these samples by means of laser spectroscopy for the purpose of hydrograph separation. The concentration of deuterium in snow before and after the experiment was also investigated. The deuterium enriched water above the natural concentration of deuterium in snowpack was detected in the outflow in 7th minute from start of spraying, but the significant increase of deuterium concentration in outflow was observed in 19th minute. The isotopic hydrograph separation estimated, that deuterium enriched rainwater became the major part (> 50% volumetric) of the outflow in 28th minute. The culmination of the outflow (1.23 l min-1) as well as deuterium enriched rainwater fraction (63.5%) in it occurred in 63th minute, i.e. right after the end of spraying. In total, 72.7 l of deuterium enriched water was sprayed on the snowpack in 62 minutes. Total volume of outflow (after 12.3 hours) water was 97.4 l, which contained 48.3 l of deuterium enriched water (i.e. 49.6 %) and 49.1 l (50.4 %) of the melted snowpack. The volume of 24.4 l of deuterium enriched spray-water was stored in the snowpack. The increased total output v. input of the water volume was caused by the warmer spray-water induced snowmelt also connecting separated liquid layers in the snowpack within the process of infiltration and drainage. Key words: deuterium tracer, rainfall simulator, snowmelt

Deuterium used as artificial tracer in column studies under saturated water flow conditions

NASA Astrophysics Data System (ADS)

Koeniger, P.; Geiges, M.; Leibundgut, Ch.

2003-04-01

In contrast to numerous investigations using deuterium as an environmental tracer, hydrological investigations with deuterium-labelled water are rather rare. Currently applications in groundwater studies are restricted due to increasing costs of spiking large water quantities but an application as intelligent tracer might be of advantage especially in combination with other tracers and under distinct environmental conditions. Therefore deuterium was applied as artificial tracer in column experiments that are well proved as a tool to characterise tracer behaviour in recent studies. Deuterium was tested in comparison to the more familiar conservative tracer fluorescein. Varying experimental conditions, e.g. column length (0.5, 1.0, 1.5 m), initial tracer concentration (0.01, 0.02, 0.2 mg) and flow velocity (1.5 to 6.0 m/d) were used to investigate tracer behaviour under saturated water flow conditions. Deuterium was analysed using an H/Device with chrome reduction connected to an isotope ratio mass spectrometer and expressed in relative concentrations [per mill V-SMOW]. Theoretical tracer breakthrough curves were calculated using a one dimensional dispersion model. The results indicate higher mean transport velocities and smaller dispersion for deuterium in all experiments. Due to different molecule properties that also determine the interaction of soil substrate and tracer, deuterium indicates a more conservative transport behaviour. Deuterium is non-toxic, completely soluble, chemically and biologically stable and not subject to light-influenced decay. Furthermore, it shows promise for investigations of water flow in the unsaturated zone, and of interactions of water in soil-plant-atmosphere systems. A further discussion of problems, together with possibilities for applying deuterium as an artificial tracer, will be presented.

First measurements of deuterium-tritium and deuterium-deuterium fusion reaction yields in ignition-scalable direct-drive implosions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Forrest, C. J.; Radha, P. B.; Knauer, J. P.

In this study, the deuterium-tritium (D-T) and deuterium-deuterium neutron yield ratio in cryogenic inertial confinement fusion (ICF) experiments is used to examine multifluid effects, traditionally not included in ICF modeling. This ratio has been measured for ignition-scalable direct-drive cryogenic DT implosions at the Omega Laser Facility using a high-dynamic-range neutron time-of-flight spectrometer. The experimentally inferred yield ratio is consistent with both the calculated values of the nuclear reaction rates and the measured preshot target-fuel composition. These observations indicate that the physical mechanisms that have been proposed to alter the fuel composition, such as species separation of the hydrogen isotopes, aremore » not significant during the period of peak neutron production in ignition-scalable cryogenic direct-drive DT implosions.« less

First measurements of deuterium-tritium and deuterium-deuterium fusion reaction yields in ignition-scalable direct-drive implosions

DOE PAGES

Forrest, C. J.; Radha, P. B.; Knauer, J. P.; ...

2017-03-03

In this study, the deuterium-tritium (D-T) and deuterium-deuterium neutron yield ratio in cryogenic inertial confinement fusion (ICF) experiments is used to examine multifluid effects, traditionally not included in ICF modeling. This ratio has been measured for ignition-scalable direct-drive cryogenic DT implosions at the Omega Laser Facility using a high-dynamic-range neutron time-of-flight spectrometer. The experimentally inferred yield ratio is consistent with both the calculated values of the nuclear reaction rates and the measured preshot target-fuel composition. These observations indicate that the physical mechanisms that have been proposed to alter the fuel composition, such as species separation of the hydrogen isotopes, aremore » not significant during the period of peak neutron production in ignition-scalable cryogenic direct-drive DT implosions.« less

Disassembly time of deuterium-cluster-fusion plasma irradiated by an intense laser pulse.

PubMed

Bang, W

2015-07-01

Energetic deuterium ions from large deuterium clusters (>10nm diameter) irradiated by an intense laser pulse (>10(16)W/cm(2)) produce DD fusion neutrons for a time interval determined by the geometry of the resulting fusion plasma. We present an analytical solution of this time interval, the plasma disassembly time, for deuterium plasmas that are cylindrical in shape. Assuming a symmetrically expanding deuterium plasma, we calculate the expected fusion neutron yield and compare with an independent calculation of the yield using the concept of a finite confinement time at a fixed plasma density. The calculated neutron yields agree quantitatively with the available experimental data. Our one-dimensional simulations indicate that one could expect a tenfold increase in total neutron yield by magnetically confining a 10-keV deuterium fusion plasma for 10ns.

Regio-Selective Intramolecular Hydrogen/Deuterium Exchange in Gas-Phase Electron Transfer Dissociation

NASA Astrophysics Data System (ADS)

Hamuro, Yoshitomo

2017-05-01

Protein backbone amide hydrogen/deuterium exchange mass spectrometry (HDX-MS) typically utilizes enzymatic digestion after the exchange reaction and before MS analysis to improve data resolution. Gas-phase fragmentation of a peptic fragment prior to MS analysis is a promising technique to further increase the resolution. The biggest technical challenge for this method is elimination of intramolecular hydrogen/deuterium exchange (scrambling) in the gas phase. The scrambling obscures the location of deuterium. Jørgensen's group pioneered a method to minimize the scrambling in gas-phase electron capture/transfer dissociation. Despite active investigation, the mechanism of hydrogen scrambling is not well-understood. The difficulty stems from the fact that the degree of hydrogen scrambling depends on instruments, various parameters of mass analysis, and peptide analyzed. In most hydrogen scrambling investigations, the hydrogen scrambling is measured by the percentage of scrambling in a whole molecule. This paper demonstrates that the degree of intramolecular hydrogen/deuterium exchange depends on the nature of exchangeable hydrogen sites. The deuterium on Tyr amide of neurotensin (9-13), Arg-Pro-Tyr-Ile-Leu, migrated significantly faster than that on Ile or Leu amides, indicating the loss of deuterium from the original sites is not mere randomization of hydrogen and deuterium but more site-specific phenomena. This more precise approach may help understand the mechanism of intramolecular hydrogen exchange and provide higher confidence for the parameter optimization to eliminate intramolecular hydrogen/deuterium exchange during gas-phase fragmentation.

Regio-Selective Intramolecular Hydrogen/Deuterium Exchange in Gas-Phase Electron Transfer Dissociation.

PubMed

Hamuro, Yoshitomo

2017-05-01

Protein backbone amide hydrogen/deuterium exchange mass spectrometry (HDX-MS) typically utilizes enzymatic digestion after the exchange reaction and before MS analysis to improve data resolution. Gas-phase fragmentation of a peptic fragment prior to MS analysis is a promising technique to further increase the resolution. The biggest technical challenge for this method is elimination of intramolecular hydrogen/deuterium exchange (scrambling) in the gas phase. The scrambling obscures the location of deuterium. Jørgensen's group pioneered a method to minimize the scrambling in gas-phase electron capture/transfer dissociation. Despite active investigation, the mechanism of hydrogen scrambling is not well-understood. The difficulty stems from the fact that the degree of hydrogen scrambling depends on instruments, various parameters of mass analysis, and peptide analyzed. In most hydrogen scrambling investigations, the hydrogen scrambling is measured by the percentage of scrambling in a whole molecule. This paper demonstrates that the degree of intramolecular hydrogen/deuterium exchange depends on the nature of exchangeable hydrogen sites. The deuterium on Tyr amide of neurotensin (9-13), Arg-Pro-Tyr-Ile-Leu, migrated significantly faster than that on Ile or Leu amides, indicating the loss of deuterium from the original sites is not mere randomization of hydrogen and deuterium but more site-specific phenomena. This more precise approach may help understand the mechanism of intramolecular hydrogen exchange and provide higher confidence for the parameter optimization to eliminate intramolecular hydrogen/deuterium exchange during gas-phase fragmentation. Graphical Abstract ᅟ.

Mass separation of deuterium and helium with conventional quadrupole mass spectrometer by using varied ionization energy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu, Yaowei; Hu, Jiansheng, E-mail: hujs@ipp.ac.cn; Wan, Zhao

2016-03-15

Deuterium pressure in deuterium-helium mixture gas is successfully measured by a common quadrupole mass spectrometer (model: RGA200) with a resolution of ∼0.5 atomic mass unit (AMU), by using varied ionization energy together with new developed software and dedicated calibration for RGA200. The new software is developed by using MATLAB with the new functions: electron energy (EE) scanning, deuterium partial pressure measurement, and automatic data saving. RGA200 with new software is calibrated in pure deuterium and pure helium 1.0 × 10{sup −6}–5.0 × 10{sup −2} Pa, and the relation between pressure and ion current of AMU4 under EE = 25 eVmore » and EE = 70 eV is obtained. From the calibration result and RGA200 scanning with varied ionization energy in deuterium and helium mixture gas, both deuterium partial pressures (P{sub D{sub 2}}) and helium partial pressure (P{sub He}) could be obtained. The result shows that deuterium partial pressure could be measured if P{sub D{sub 2}} > 10{sup −6} Pa (limited by ultimate pressure of calibration vessel), and helium pressure could be measured only if P{sub He}/P{sub D{sub 2}} > 0.45, and the measurement error is evaluated as 15%. This method is successfully employed in EAST 2015 summer campaign to monitor deuterium outgassing/desorption during helium discharge cleaning.« less

Electrical properties of double layer dielectric structures for space technology

NASA Astrophysics Data System (ADS)

Lian, Anqing

1993-04-01

Polymeric films such as polyimide (PI) and polyethylene terephthalate (PET) are used in space technology as thermal blankets. Thin SiO2 and SiN coatings plasma deposited onto PI and PET surfaces were proposed to protect the blanket materials against the space environment. The electrical properties of this kind of dual layer dielectric structure were investigated to understand the mechanisms for suppressing charge accumulation and flashover. Bulk and surface electrical conductivities of thin single-layer PI and PET samples and of the dual layer SiO2 and SiN combinations with PI and PET were measured in a range of applied electrical fields. The capacitance voltage (CV) technique was used for analyzing charge transport and distribution in the structures. The electric current in the bulk of the SiO2/PI and SiN/PI samples was found to depend on the polarity of the electric field. Other samples did not exhibit any such polarity effect. The polarity dependence is attributed to charge trapping at the PI/plasma deposit interface. The CV characteristics of the Al-PI-SiO2-Si structure confirm that charges which can modify the local electric field can be trapped near the interface. A model is proposed to interpret the properties of the currents in dual layer structures. This model can semi-quantitatively explain all the observed results.

Arc initiation in cathodic arc plasma sources

DOEpatents

Anders, Andre

2002-01-01

A "triggerless" arc initiation method and apparatus is based on simply switching the arc supply voltage to the electrodes (anode and cathode). Neither a mechanical trigger electrode nor a high voltage flashover from a trigger electrode is required. A conducting path between the anode and cathode is provided, which allows a hot spot to form at a location where the path connects to the cathode. While the conductive path is eroded by the cathode spot action, plasma deposition ensures the ongoing repair of the conducting path. Arc initiation is achieved by simply applying the relatively low voltage of the arc power supply, e.g. 500 V-1 kV, with the insulator between the anode and cathode coated with a conducting layer and the current at the layer-cathode interface concentrated at one or a few contact points. The local power density at these contact points is sufficient for plasma production and thus arc initiation. A conductive surface layer, such as graphite or the material being deposited, is formed on the surface of the insulator which separates the cathode from the anode. The mechanism of plasma production (and arc initiation) is based on explosive destruction of the layer-cathode interface caused by joule heating. The current flow between the thin insulator coating and cathode occurs at only a few contact points so the current density is high.

The deuterium content of water in some volcanic glasses

USGS Publications Warehouse

Friedman, I.; Smith, R.L.

1958-01-01

The deuterium-hydrogen composition (relative to Lake Michigan water = 0.0) of water extractsd from coexisting perlite and obsidian from eleven different localities was determined. The water content of the obsidians is generally from 0.09 to 0.29 per cent by weight, though two samples from near Olancha, California, contain about 0.92 per cent. The relative deuterium concentration is from -4.6 to -12.3 per cent. The coexisting perlite contains from 2.0 to 3.8 per cent of water with a relative deuterium concentration of -3.1 to -16.6 per cent. The deuterium concentration in the perlites is not related to that in the enclosed obsidian. The deuterium concentration in the perlite water is related to the deuterium concentration of the modern meteoric water and the perlite water contains approximately 4 per cent less deuterium than does the groundwater of the area in which the perlites occur. The above relations hold true for perlites from northern New Mexico, east slope of the Sierra Nevada. California Coast Range, Yellowstone Park, Wyoming, and New Zealand. As the water in the obsidian is unrelated to meteoric water, but the enclosing perlite water is related, we believe that this is evidence for the secondary hydration of obsidian to form high water content perlitic glass. ?? 1958.

Lightning protection of distribution lines

DOE Office of Scientific and Technical Information (OSTI.GOV)

McDermott, T.E.; Short, T.A.; Anderson, J.G.

1994-01-01

This paper reports a study of distribution line lightning performance, using computer simulations of lightning overvoltages. The results of previous investigations are extended with a detailed model of induced voltages from nearby strokes, coupled into a realistic power system model. The paper also considers the energy duty of distribution-class surge arresters exposed to direct strokes. The principal result is that widely separated pole-top arresters can effectively protect a distribution line from induced-voltage flashovers. This means that nearby lightning strokes need not be a significant lightning performance problem for most distribution lines.

Production of heavy water

DOEpatents

Spencer, Larry S.; Brown, Sam W.; Phillips, Michael R.

2017-06-06

Disclosed are methods and apparatuses for producing heavy water. In one embodiment, a catalyst is treated with high purity air or a mixture of gaseous nitrogen and oxygen with gaseous deuterium all together flowing over the catalyst to produce the heavy water. In an alternate embodiment, the deuterium is combusted to form the heavy water. In an alternate embodiment, gaseous deuterium and gaseous oxygen is flowed into a fuel cell to produce the heavy water. In various embodiments, the deuterium may be produced by a thermal decomposition and distillation process that involves heating solid lithium deuteride to form liquid lithium deuteride and then extracting the gaseous deuterium from the liquid lithium deuteride.

Materials Analysis of Transient Plasma-Wall Interactions

DTIC Science & Technology

2014-05-13

such as copper, aluminum, zirconium, titanium, and tungsten) and ceramics (beryllia, aluminum nitride, silicon carbide , etc.). These materials were...formation of silicon carbide . Therefore, a flat Macor disk was polished, and prepared for deuterium exposure by sonicating the sample in both methanol...of silicon constituents whereas the exposed sample clearly shows the addition of carbide and silicon segregation on the surface. 10 AFOSR

Reduced deuterium retention in simultaneously damaged and annealed tungsten

NASA Astrophysics Data System (ADS)

Simmonds, M. J.; Wang, Y. Q.; Barton, J. L.; Baldwin, M. J.; Yu, J. H.; Doerner, R. P.; Tynan, G. R.

2017-10-01

Deuterium (D) retention in polycrystalline tungsten (W) with copper (Cu) ion damage concurrently produced at elevated surface temperature is investigated. An in situ heated stage held W samples at a controlled temperature up to 1243 K, which were subjected to displacement damage produced by 3.4 MeV Cu ions. D retention is subsequently explored by exposure of the W samples held at 383 K to a D2 plasma ion fluence of 1024 D+/m2. Nuclear reaction analysis (NRA), utilizing the D(3He,p)4He nuclear reaction, is used to probe the D concentration in the near surface up to 6 μm. Thermal desorption spectroscopy (TDS) is used to measure outgassed HD and D2 molecules to determine the bulk D concentration. Both NRA and TDS measure a significant reduction in D retention for samples damaged at elevated temperature. TDS quantitatively shows that the lowest energy trap remains largely unaffected while higher energy traps, induced by Cu ions, are annealed and approach intrinsic concentrations as the temperature during ion damage approaches 1243 K. Analysis of TDS data yields an activation energy of (0.10 ± 0.02) eV for recovery of ion-damage induced traps at elevated temperature.

Modeling Deuterium Release from Plasma Implanted Surfaces

NASA Astrophysics Data System (ADS)

Grossman, A. A.; Doerner, R.; Hirooka, Y.; Luckhardt, S. C.; Sze, F. C.

1997-11-01

When energetic ions or atoms of hydrogen isotopes interact with a solid surface, they may either be reflected or they may be implanted, a slowing down process within the subsurface layer of the energetic particles to thermal velocities. Subsequent interactions of the thermalized particles are those of diffusion and trapping within the material and the possibility of re-emission from the solid via desorption. The diffusion equation and its boundary conditions govern the transport of this thermalized hydrogen within the material. Diffusivities obey an Arrhenius law over as much as fourteen orders of magnitude for the temperature range of interest for a fusion reactor first wall and divertor plate. Using TMAP4, a variety of diffusion models are set up for comparison with experiments on PISCES which involve implantation and desorption of deuterium from beryllium, tungsten, carbon and boron carbide. The parameters and characteristics of the models which give the closest fit to the experimental data are reported. At the high fluences of these experiments, it is necessary to take into account saturation effects during implantation using a separate implantation layer with thickness given by TRIM and a higher trapping to lattice ratio than in the bulk in order to model the experimental data.

Enhancement of deuterium retention in damaged tungsten by plasma-induced defect clustering

NASA Astrophysics Data System (ADS)

Jin, Younggil; Roh, Ki-Baek; Sheen, Mi-Hyang; Kim, Nam-Kyun; Song, Jaemin; Kim, Young-Woon; Kim, Gon-Ho

2017-12-01

The enhancement of deuterium retention was investigated for tungsten in the presence of both 2.8 MeV self-ion induced cascade damage and fuel hydrogen isotope plasma. Vacancy clustering in cascade damaged polycrystalline tungsten occurred due to deuterium irradiation and was observed near the grain boundary by using all-step transmission electron microscopy analysis. Analysis of the highest desorption temperature peak using thermal desorption spectroscopy supports reasonable evidence of defect clustering in the damaged polycrystalline tungsten. The defect clustering was neither observed on the damaged polycrystalline tungsten without deuterium irradiation nor on the damaged single-crystalline tungsten with deuterium irradiation. This result implies the synergetic role of deuterium and grain boundary on defect clustering. This study proposes a path for the defect transform from point defect to defect cluster, by the agglomeration between irradiated deuterium and cascade damage-induced defect. This agglomeration may induce more severe damage on the tungsten divertor at which the high fuel hydrogen ions, fast neutrons, and self-ions are irradiated simultaneously and it would increase the in-vessel tritium inventory.

Study of the ionization rate of the released deuterium in vacuum arc discharges with metal deuteride cathodes

NASA Astrophysics Data System (ADS)

Liu, Fei-Xiang; Long, Ji-Dong; Zheng, Le; Dong, Pan; Li, Chen; Chen, Wei

2018-02-01

The ionization rate of the released deuterium from a metal deuteride cathode in vacuum arc discharges is investigated by both experiments and modeling analysis. Experimental results show that the deuterium ionization rate increases from 2% to 30% with the increasing arc current in the range of 2-100 A. Thus the full ionization assumption, as is widely used in arc plasma simulations, is not satisfied for the released deuterium at low discharge current. According to the modeling results, the neutral-to-ion conversion efficiency for the deuterium traveling across the cathodic spot region can be significantly less than one, due to the fast plasma expansion and rarefaction in the vacuum. In addition, the model also reveals that, unlike the metal atoms which are mainly ionized in the sheath region and flow back to the cathode, the deuterium ionization primarily occurs in the quasi-neutral region and moves towards the anode. Consequently, the cathodic sheath layer acts like a filter that increases the deuterium fraction beyond the sheath region.

Tritium target manufacturing for use in accelerators

NASA Astrophysics Data System (ADS)

Bach, P.; Monnin, C.; Van Rompay, M.; Ballanger, A.

2001-07-01

As a neutron tube manufacturer, SODERN is now in charge of manufacturing tritium targets for accelerators, in cooperation with CEA/DAM/DTMN in Valduc. Specific deuterium and tritium targets are manufactured on request, according to the requirements of the users, starting from titanium target on copper substrate, and going to more sophisticated devices. A wide range of possible uses is covered, including thin targets for neutron calibration, thick targets with controlled loading of deuterium and tritium, rotating targets for higher lifetimes, or large size rotating targets for accelerators used in boron neutron therapy. Activity of targets lies in the 1 to 1000 Curie, diameter of targets being up to 30 cm. Special targets are also considered, including surface layer targets for lowering tritium desorption under irradiation, or those made from different kinds of occluders such as titanium, zirconium, erbium, scandium, with different substrates. It is then possible to optimize either neutron output, or lifetime and stability, or thermal behavior.

Experimental study and modelling of deuterium thermal release from Be-D co-deposited layers

NASA Astrophysics Data System (ADS)

Baldwin, M. J.; Schwarz-Selinger, T.; Doerner, R. P.

2014-07-01

A study of the thermal desorption of deuterium from 1 µm thick co-deposited Be-(0.1)D layers formed at 330 K by a magnetron sputtering technique is reported. A range of thermal desorption rates 0 ⩽ β ⩽ 1.0 K s-1 are explored with a view to studying the effectiveness of the proposed ITER wall and divertor bake procedure (β = 0 K s-1) to be carried out at 513 and 623 K. Fixed temperature bake durations up to 24 h are examined. The experimental thermal release data are used to validate a model input into the Tritium Migration and Analysis Program (TMAP-7). Good agreement with experiment is observed for a TMAP-7 model incorporating trap populations of activation energies for D release of 0.80 and 0.98 eV, and a dynamically computed surface D atomic to molecular recombination rate.

Reaction rates and kinetic isotope effects of H{sub 2} + OH → H{sub 2}O + H

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meisner, Jan; Kästner, Johannes, E-mail: kaestner@theochem.uni-stuttgart.de

2016-05-07

We calculated reaction rate constants including atom tunneling of the reaction of dihydrogen with the hydroxy radical down to a temperature of 50 K. Instanton theory and canonical variational theory with microcanonical optimized multidimensional tunneling were applied using a fitted potential energy surface [J. Chen et al., J. Chem. Phys. 138, 154301 (2013)]. All possible protium/deuterium isotopologues were considered. Atom tunneling increases at about 250 K (200 K for deuterium transfer). Even at 50 K the rate constants of all isotopologues remain in the interval 4 ⋅ 10{sup −20} to 4 ⋅ 10{sup −17} cm{sup 3} s{sup −1}, demonstrating thatmore » even deuterated versions of the title reaction are possibly relevant to astrochemical processes in molecular clouds. The transferred hydrogen atom dominates the kinetic isotope effect at all temperatures.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Biewer, Theodore M.; Bigelow, Tim S.; Caneses Marin, Juan F.

The Prototype Material Plasma Exposure Experiment at the Oak Ridge National Laboratory utilizes a variety of power systems to generate and deliver a high heat flux plasma onto the surface of material targets. In the experiments described here, a deuterium plasma is produced via a ~100 kW, 13.56 MHz RF helicon source, to which ~20 kW of 28 GHz microwave power is applied. The electron density and temperature profiles are measured using a Thomson scattering (TS) diagnostic, and indicate that the electron density is centrally peaked. In the core of the plasma column, the electron density is higher than themore » cut-off density (~0.9 × 1019 m -3) for the launched mixture of X- and O-mode electron cyclotron heating waves to propagate. TS measurements indicate electron temperature increases from ~5 eV to ~20 eV during 28 GHz power application when the neutral deuterium pressure is reduced below 0.13 Pa (~1 mTorr.).« less

The effects of deuterium on static posture control

NASA Technical Reports Server (NTRS)

Layne, Charles S.

1990-01-01

A significant operational problem impacting upon the Space Shuttle program involves the astronaut's ability to safely egress from the Orbiter during an emergency situation. Following space flight, astronauts display significant movement problems. One variable which may contribute to increased movement ataxia is deuterium (D2O). Deuterium is present in low levels within the Orbiter's water supply but may accumulate to significant physiological levels during lengthy missions. Deuterium was linked to a number of negative physiological responses, including motion sickness, decreased metabolism, and slowing of neural conduction velocity. The effects of D2O on static postural control in response to a range of dosage levels were investigated. Nine sugjects were divided into three groups of three subjects each. The groups were divided into a low, medium, and a high D2O dosage group. The subjects static posture was assessed with the use of the EquiTest systems, a commercially available postural control evaluation system featuring movable force plates and a visual surround that can be servoed to the subject's sway. In addition to the force plate information, data about the degree of subject sway about the hips and shoulders was obtained. Additionally, surface electromyographic (EMG) data from the selected lower limb muscles were collected along with saliva samples used to determine the amount of deuterium enrichment following D2O ingestion. Two baseline testing sessions were performed using the EquiTest testing protocol prior to ingestion of the D2O. Thirty minutes after dosing, subjects again performed the tests. Two more post-dosing tests were run with an interest interval of one hour. Preliminary data anlaysis indicates that only subjects in the igh dose group displayed any significant static postural problems. Future analyses of the sway and EMG is expected to reveal significant variations in the subject's postural control strategy following D2O dosing. While functionally significant static postural problems were not commonly observed, subjects in both the medium and high dosage groups displayed significant, and in some cases, severe voluntary movement problems.

Palladium-catalyzed Br/D exchange of arenes: Selective deuterium incorporation with versatile functional group tolerance and high efficiency

DOE PAGES

Zhang, Honghai -Hai; Bonnesen, Peter V.; Hong, Kunlun

2015-07-13

There is a facile method for introducing one or more deuterium atoms onto an aromatic nucleus via Br/D exchange with high functional group tolerance and high incorporation efficiency is disclosed. Deuterium-labeled aryl chlorides and aryl borates which could be used as substrates in cross-coupling reactions to construct more complicated deuterium-labeled compounds can also be synthesized by this method.

Is High Primordial Deuterium Consistent with Galactic Evolution?

NASA Astrophysics Data System (ADS)

Tosi, Monica; Steigman, Gary; Matteucci, Francesca; Chiappini, Cristina

1998-05-01

Galactic destruction of primordial deuterium is inevitably linked through star formation to the chemical evolution of the Galaxy. The relatively high present gas content and low metallicity suggest only modest D destruction. In concert with deuterium abundances derived from solar system and/or interstellar observations, this suggests a primordial deuterium abundance in possible conflict with data from some high-redshift, low-metallicity QSO absorbers. We have explored a variety of chemical evolution models including infall of processed material and early, supernovae-driven winds with the aim of identifying models with large D destruction that are consistent with the observations of stellar-produced heavy elements. When such models are confronted with data, we reconfirm that only modest destruction of deuterium (less than a factor of 3) is permitted. When combined with solar system and interstellar data, these results favor the low deuterium abundances derived for the QSO absorbers by Tytler et al.

Tungsten nitride coatings obtained by HiPIMS as plasma facing materials for fusion applications

NASA Astrophysics Data System (ADS)

Tiron, Vasile; Velicu, Ioana-Laura; Porosnicu, Corneliu; Burducea, Ion; Dinca, Paul; Malinský, Petr

2017-09-01

In this work, tungsten nitride coatings with nitrogen content in the range of 19-50 at% were prepared by reactive multi-pulse high power impulse magnetron sputtering as a function of the argon and nitrogen mixture and further exposed to a deuterium plasma jet. The elemental composition, morphological properties and physical structure of the samples were investigated by Rutherford backscattering spectrometry, atomic force microscopy and X-ray diffraction. Deuterium implantation was performed using a deuterium plasma jet and its retention in nitrogen containing tungsten films was investigated using thermal desorption spectrometry. Deuterium retention and release behaviour strongly depend on the nitrogen content in the coatings and the films microstructure. All nitride coatings have a polycrystalline structure and retain a lower deuterium level than the pure tungsten sample. Nitrogen content in the films acts as a diffusion barrier for deuterium and leads to a higher desorption temperature, therefore to a higher binding energy.

New method of a "point-like" neutron source creation based on sharp focusing of high-current deuteron beam onto deuterium-saturated target for neutron tomography

NASA Astrophysics Data System (ADS)

Golubev, S.; Skalyga, V.; Izotov, I.; Sidorov, A.

2017-02-01

A possibility of a compact powerful point-like neutron source creation is discussed. Neutron yield of the source based on deuterium-deuterium (D-D) reaction is estimated at the level of 1011 s-1 (1013 s-1 for deuterium-tritium reaction). The fusion takes place due to bombardment of deuterium- (or tritium) loaded target by high-current focused deuterium ion beam with energy of 100 keV. The ion beam is formed by means of high-current quasi-gasdynamic ion source of a new generation based on an electron cyclotron resonance (ECR) discharge in an open magnetic trap sustained by powerful microwave radiation. The prospects of proposed generator for neutron tomography are discussed. Suggested method is compared to the point-like neutron sources based on a spark produced by powerful femtosecond laser pulses.

Disassembly time of deuterium-cluster-fusion plasma irradiated by an intense laser pulse

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bang, W.

Energetic deuterium ions from large deuterium clusters (>10 nm diameter) irradiated by an intense laser pulse (>10¹⁶ W/cm²) produce DD fusion neutrons for a time interval determined by the geometry of the resulting fusion plasma. We show an analytical solution of this time interval, the plasma disassembly time, for deuterium plasmas that are cylindrical in shape. Assuming a symmetrically expanding deuterium plasma, we calculate the expected fusion neutron yield and compare with an independent calculation of the yield using the concept of a finite confinement time at a fixed plasma density. The calculated neutron yields agree quantitatively with the availablemore » experimental data. Our one-dimensional simulations indicate that one could expect a tenfold increase in total neutron yield by magnetically confining a 10 - keV deuterium fusion plasma for 10 ns.« less

Fast Faraday cup for fast ion beam TOF measurements in deuterium filled plasma focus device and correlation with Lee model

NASA Astrophysics Data System (ADS)

Damideh, Vahid; Ali, Jalil; Saw, Sor Heoh; Rawat, Rajdeep Singh; Lee, Paul; Chaudhary, Kashif Tufail; Rizvi, Zuhaib Haider; Dabagh, Shadab; Ismail, Fairuz Diyana; Sing, Lee

2017-06-01

In this work, the design and construction of a 50 Ω fast Faraday cup and its results in correlation with the Lee Model Code for fast ion beam and ion time of flight measurements for a Deuterium filled plasma focus device are presented. Fast ion beam properties such as ion flux, fluence, speed, and energy at 2-8 Torr Deuterium are studied. The minimum 34 ns full width at half maximum ion signal at 12 kV, 3 Torr Deuterium in INTI PF was captured by a Faraday cup. The maximum ion energy of 67 ± 5 keV at 4 Torr Deuterium was detected by the Faraday cup. Ion time of flight measurements by the Faraday cup show consistent correlation with Lee Code results for Deuterium especially at near to optimum pressures.

Disassembly time of deuterium-cluster-fusion plasma irradiated by an intense laser pulse

DOE PAGES

Bang, W.

2015-07-02

Energetic deuterium ions from large deuterium clusters (>10 nm diameter) irradiated by an intense laser pulse (>10¹⁶ W/cm²) produce DD fusion neutrons for a time interval determined by the geometry of the resulting fusion plasma. We show an analytical solution of this time interval, the plasma disassembly time, for deuterium plasmas that are cylindrical in shape. Assuming a symmetrically expanding deuterium plasma, we calculate the expected fusion neutron yield and compare with an independent calculation of the yield using the concept of a finite confinement time at a fixed plasma density. The calculated neutron yields agree quantitatively with the availablemore » experimental data. Our one-dimensional simulations indicate that one could expect a tenfold increase in total neutron yield by magnetically confining a 10 - keV deuterium fusion plasma for 10 ns.« less

Report on the deuterium retention in CVD coated W on SiC in support of the Ultramet Company’s Small Business Innovation Research (SBIR) project: SOW DE-FG02-07ER84941

DOE Office of Scientific and Technical Information (OSTI.GOV)

Masashi Shimada

2012-06-01

A tungsten (W) coated (0.0005-inch thickness) silicon carbide (SiC) (1.0-inch diameter and 0.19-inch thickness) sample was exposed to a divertor relevant high-flux (~1022 m-2s-1) deuterium plasma at 200 and 400°C in the Idaho National Laboratory’s (INL’s) Tritium Plasma Experiment (TPE), and the total deuterium retention was subsequently measured via the thermal desorption spectroscopy (TDS) method. The deuterium retentions were 6.4x1019 m-2 and 1.7x1020 m-2, for 200 and 400°C exposure, respectively. The Tritium Migration Analysis Program (TMAP) was used to analyze the measured TDS spectrum to investigate the deuterium behavior in the W coated SiC, and the results indicated that mostmore » of the deuterium was trapped in the W coated layer even at 400°C. This thin W layer (0.0005-inch ~ 13µm thickness) prevented deuterium ions from bombarding directly into the SiC substrate, minimizing erosion of SiC and damage creation via ion bombardment. The shift in the D desorption peak in the TDS spectra from 200 C to 400°C can be attributed to D migration to the bulk material. This unexpectedly low deuterium retention and short migration might be due to the porous nature of the tungsten coating, which can decrease the solution concentration of deuterium atoms.« less

Vacuum Ultraviolet Radiation Desorption of Molecular Contaminants Deposited on Quartz Crystal Microbalances

NASA Technical Reports Server (NTRS)

Albyn, Keith; Burns, Dewitt

2006-01-01

Recent quartz crystal microbalance measurements made in the Marshall Space Flight Center, Photo-Deposition Facility, for several materials, recorded a significant loss of deposited contaminants when the deposition surface of the microbalance was illuminated by a deuterium lamp. These measurements differ from observations made by other investigators in which the rate of deposition increased significantly when the deposition surface was illuminated with vacuum ultraviolet radiation. These observations suggest that the accelerated deposition of molecular contaminants on optically sensitive surfaces is dependant upon the contaminant being deposited and must be addressed during the materials selection process by common material screening techniques.

Radiation damage in WC studied with MD simulations

NASA Astrophysics Data System (ADS)

Träskelin, P.; Björkas, C.; Juslin, N.; Vörtler, K.; Nordlund, K.

2007-04-01

Studying radiation damage in tungsten carbide (WC) is of importance due to its applications in fusion reactors. We have used molecular dynamics to study both deuterium induced sputtering and modification of WC surfaces and collision cascades in bulk WC. For collision cascades in bulk WC we note a massive recombination and major elemental asymmetry for the damage. Studying the erosion of WC surfaces, we find that C can erode through swift chemical sputtering, while W does not sputter more easily than from pure W. The amorphization of the surface and the D-content due to the D bombardment is important for the damage production and sputtering process.

Process for manufacturing hollow fused-silica insulator cylinder

DOEpatents

Sampayan, Stephen E.; Krogh, Michael L.; Davis, Steven C.; Decker, Derek E.; Rosenblum, Ben Z.; Sanders, David M.; Elizondo-Decanini, Juan M.

2001-01-01

A method for building hollow insulator cylinders that can have each end closed off with a high voltage electrode to contain a vacuum. A series of fused-silica round flat plates are fabricated with a large central hole and equal inside and outside diameters. The thickness of each is related to the electron orbit diameter of electrons that escape the material surface, loop, and return back. Electrons in such electron orbits can support avalanche mechanisms that result in surface flashover. For example, the thickness of each of the fused-silica round flat plates is about 0.5 millimeter. In general, the thinner the better. Metal, such as gold, is deposited onto each top and bottom surface of the fused-silica round flat plates using chemical vapor deposition (CVD). Eutectic metals can also be used with one alloy constituent on the top and the other on the bottom. The CVD, or a separate diffusion step, can be used to defuse the deposited metal deep into each fused-silica round flat plate. The conductive layer may also be applied by ion implantation or gas diffusion into the surface. The resulting structure may then be fused together into an insulator stack. The coated plates are aligned and then stacked, head-to-toe. Such stack is heated and pressed together enough to cause the metal interfaces to fuse, e.g., by welding, brazing or eutectic bonding. Such fusing is preferably complete enough to maintain a vacuum within the inner core of the assembled structure. A hollow cylinder structure results that can be used as a core liner in a dielectric wall accelerator and as a vacuum envelope for a vacuum tube device where the voltage gradients exceed 150 kV/cm.

Reprint of: Effects of cold deformation, electron irradiation and extrusion on deuterium desorption behavior in Zr-1%Nb alloy

NASA Astrophysics Data System (ADS)

Morozov, O.; Mats, O.; Mats, V.; Zhurba, V.; Khaimovich, P.

2018-01-01

The present article introduces the data of analysis of ranges of ion-implanted deuterium desorption from Zr-1% Nb alloy. The samples studied underwent plastic deformation, low temperature extrusion and electron irradiation. Plastic rolling of the samples at temperature ∼300 K resulted in plastic deformation with the degree of ε = 3.9 and the formation of nanostructural state with the average grain size of d = 61 nm. The high degree of defectiveness is shown in thermodesorption spectrum as an additional area of the deuterium desorption in the temperature ranges 650-850 K. The further processing of the sample (that had undergone plastic deformation by plastic rolling) with electron irradiation resulted in the reduction of the average grain size (58 nm) and an increase in borders concentration. As a result the amount of deuterium desorpted increased in the temperature ranges 650-900 K. In case of Zr-1% Nb samples deformed by extrusion the extension of desorption area is observed towards the temperature reduction down to 420 K. The formation of the phase state of deuterium solid solution in zirconium was not observed. The structural state behavior is a control factor in the process of deuterium thermodesorption spectrum structure formation with a fixed implanted deuterium dose (hydrogen diagnostics). It appears as additional temperature ranges of deuterium desorption depending on the type, character and defect content.

Understanding fuel magnetization and mix using secondary nuclear reactions in magneto-inertial fusion.

PubMed

Schmit, P F; Knapp, P F; Hansen, S B; Gomez, M R; Hahn, K D; Sinars, D B; Peterson, K J; Slutz, S A; Sefkow, A B; Awe, T J; Harding, E; Jennings, C A; Chandler, G A; Cooper, G W; Cuneo, M E; Geissel, M; Harvey-Thompson, A J; Herrmann, M C; Hess, M H; Johns, O; Lamppa, D C; Martin, M R; McBride, R D; Porter, J L; Robertson, G K; Rochau, G A; Rovang, D C; Ruiz, C L; Savage, M E; Smith, I C; Stygar, W A; Vesey, R A

2014-10-10

Magnetizing the fuel in inertial confinement fusion relaxes ignition requirements by reducing thermal conductivity and changing the physics of burn product confinement. Diagnosing the level of fuel magnetization during burn is critical to understanding target performance in magneto-inertial fusion (MIF) implosions. In pure deuterium fusion plasma, 1.01 MeV tritons are emitted during deuterium-deuterium fusion and can undergo secondary deuterium-tritium reactions before exiting the fuel. Increasing the fuel magnetization elongates the path lengths through the fuel of some of the tritons, enhancing their probability of reaction. Based on this feature, a method to diagnose fuel magnetization using the ratio of overall deuterium-tritium to deuterium-deuterium neutron yields is developed. Analysis of anisotropies in the secondary neutron energy spectra further constrain the measurement. Secondary reactions also are shown to provide an upper bound for the volumetric fuel-pusher mix in MIF. The analysis is applied to recent MIF experiments [M. R. Gomez et al., Phys. Rev. Lett. 113, 155003 (2014)] on the Z Pulsed Power Facility, indicating that significant magnetic confinement of charged burn products was achieved and suggesting a relatively low-mix environment. Both of these are essential features of future ignition-scale MIF designs.

Method for nondestructive fuel assay of laser fusion targets

DOEpatents

Farnum, Eugene H.; Fries, R. Jay

1976-01-01

A method for nondestructively determining the deuterium and tritium content of laser fusion targets by counting the x rays produced by the interaction of tritium beta particles with the walls of the microballoons used to contain the deuterium and tritium gas mixture under high pressure. The x rays provide a direct measure of the tritium content and a means for calculating the deuterium content using the initial known D-T ratio and the known deuterium and tritium diffusion rates.

Development of a plasma focus neutron source powered by an explosive magnetic generator

NASA Astrophysics Data System (ADS)

Ablesimov, V. E.; Andrianov, A. V.; Bazanov, A. A.; Glybin, A. M.; Dolin, Yu. N.; Drozdov, I. Yu.; Drozdov, Yu. M.; Duday, P. V.; Zimenkov, A. A.; Ivanov, V. A.; Ivanovskii, A. V.; Kalinychev, A. E.; Karpov, G. V.; Kraev, A. I.; Lomtev, S. S.; Nudikov, V. N.; Pak, S. V.; Pozdov, N. I.; Polyushko, S. M.; Rybakov, A. F.; Skobelev, A. N.; Turov, A. N.; Fevralev, A. Yu.

2015-01-01

This paper presents the results of laboratory and explosive experiments with a plasma focus discharge Mather-type chamber at a discharge current amplitude of 1.3-1.4 MA. It has been found that in laboratory experiments, the yield of a deuterium-deuterium neutrons reached 1011, and in an explosive experiment using the chamber filled with a deuterium-tritium gas mixture, the integral yield of a deuterium-tritium neutrons with an energy of 14 MeV was more than 1012 neutrons.

Ethylene hydrogenation catalysis on Pt(111) single-crystal surfaces studied by using mass spectrometry and in situ infrared absorption spectroscopy

NASA Astrophysics Data System (ADS)

Tillekaratne, Aashani; Simonovis, Juan Pablo; Zaera, Francisco

2016-10-01

The catalytic hydrogenation of ethylene promoted by a Pt(111) single crystal was studied by using a ultrahigh-vacuum surface-science instrument equipped with a so-called high-pressure cell. Kinetic data were acquired continuously during the catalytic conversion of atmospheric-pressure mixtures of ethylene and hydrogen by using mass spectrometry while simultaneously characterizing the surface species in operando mode by reflection-absorption infrared spectroscopy (RAIRS). Many observations reported in previous studies of this system were corroborated, including the presence of adsorbed alkylidyne intermediates during the reaction and the zero-order dependence of the rate of hydrogenation on the pressure of ethylene. In addition, the high quality of the kinetic data, which could be recorded continuously versus time and processed to calculate time-dependent turnover frequencies (TOFs), afforded a more detailed analysis of the mechanism. Specifically, deuterium labeling could be used to estimate the extent of isotope scrambling reached with mixed-isotope-substituted reactants (C2H4 + D2 and C2D4 + H2). Perhaps the most important new observation from this work is that, although extensive H-D exchange takes place on ethylene before being fully converted to ethane, the average stoichiometry of the final product retains the expected stoichiometry of the gas mixture, that is, four regular hydrogen atoms and two deuteriums per ethane molecule in the case of the experiments with C2H4 + D2. This means that no hydrogen atoms are removed from the surface via their inter-recombination to produce X2 (X = H or D). It is concluded that, under catalytic conditions, hydrogen surface recombination is much slower than ethylene hydrogenation and H-D exchange.

H2 Ortho-to-para Conversion on Grains: A Route to Fast Deuterium Fractionation in Dense Cloud Cores?

NASA Astrophysics Data System (ADS)

Bovino, S.; Grassi, T.; Schleicher, D. R. G.; Caselli, P.

2017-11-01

Deuterium fractionation, I.e., the enhancement of deuterated species with respect to non-deuterated ones, is considered to be a reliable chemical clock of star-forming regions. This process is strongly affected by the ortho-to-para H2 ratio. In this Letter we explore the effect of the ortho-para (o-p) H2 conversion on grains on the deuteration timescale in fully-depleted dense cores, including the most relevant uncertainties that affect this complex process. We show that (I) the o-p H2 conversion on grains is not strongly influenced by the uncertainties on the conversion time and the sticking coefficient, and (II) that the process is controlled by the temperature and the residence time of ortho-H2 on the surface, I.e., by the binding energy. We find that for binding energies between 330 and 550 K, depending on the temperature, the o-p H2 conversion on grains can shorten the deuterium fractionation timescale by orders of magnitude, opening a new route for explaining the large observed deuteration fraction D frac in dense molecular cloud cores. Our results suggest that the star formation timescale, when estimated through the timescale to reach the observed deuteration fractions, might be shorter than previously proposed. However, more accurate measurements of the binding energy are needed in order to better assess the overall role of this process.

Measurement of deuterium-labeled phylloquinone in plasma by LC-APCI-MS

USDA-ARS?s Scientific Manuscript database

Deuterium-labeled vegetables were fed to humans for the measurement of both unlabeled and deuterium-labeled phylloquinone in plasma. We developed a technique to determine the quantities of these compounds using liquid chromatography/mass spectrometry with atmospheric pressure chemical ionization (LC...

Thermodynamic and electrical properties of laser-shocked liquid deuterium

NASA Astrophysics Data System (ADS)

He, Zhiyu; Jia, Guo; Zhang, Fan; Luo, Kui; Huang, Xiuguang; Shu, Hua; Fang, Zhiheng; Ye, Junjian; Xie, Zhiyong; Xia, Miao; Fu, Sizu

2018-01-01

Liquid deuterium at high pressure and temperature has been observed to undergo significant electronic structural changes. Reflectivity and temperature measurements of liquid deuterium up to around 70 GPa were obtained using a quartz standard. The observed specific heat of liquid deuterium approaches the Dulong-Petit limit above 1 eV. Discussions on specific heat indicate a molecular dissociation below 1 eV and fully dissociated above 1.5 eV. Also, the electrical conductivity of deuterium estimated from reflectivity reaches 1.3 × 105 (Ωṡm)-1, proving that deuterium in this condition is a conducting degenerate liquid metal and undergo an insulator-metal transition. The results from specific heat, carrier density and conductivity agreed well with each other, which might be a reinforcement of the insulator-metal transition and the molecular dissociation. In addition, a new correction method of reflectivity in temperature calculation was proposed to improve the accuracy of temperature results. A new "dynamic calibration" was introduced in this work to make the experiments simpler and more accurate.

First Measurements of Deuterium-Tritium and Deuterium-Deuterium Fusion Reaction Yields in Ignition-Scalable Direct-Drive Implosions

NASA Astrophysics Data System (ADS)

Forrest, C. J.; Radha, P. B.; Knauer, J. P.; Glebov, V. Yu.; Goncharov, V. N.; Regan, S. P.; Rosenberg, M. J.; Sangster, T. C.; Shmayda, W. T.; Stoeckl, C.; Gatu Johnson, M.

2017-03-01

The deuterium-tritium (D-T) and deuterium-deuterium neutron yield ratio in cryogenic inertial confinement fusion (ICF) experiments is used to examine multifluid effects, traditionally not included in ICF modeling. This ratio has been measured for ignition-scalable direct-drive cryogenic DT implosions at the Omega Laser Facility [T. R. Boehly et al., Opt. Commun. 133, 495 (1997), 10.1016/S0030-4018(96)00325-2] using a high-dynamic-range neutron time-of-flight spectrometer. The experimentally inferred yield ratio is consistent with both the calculated values of the nuclear reaction rates and the measured preshot target-fuel composition. These observations indicate that the physical mechanisms that have been proposed to alter the fuel composition, such as species separation of the hydrogen isotopes [D. T. Casey et al., Phys. Rev. Lett. 108, 075002 (2012), 10.1103/PhysRevLett.108.075002], are not significant during the period of peak neutron production in ignition-scalable cryogenic direct-drive DT implosions.

Site occupancy of interstitial deuterium atoms in face-centred cubic iron

PubMed Central

Machida, Akihiko; Saitoh, Hiroyuki; Sugimoto, Hidehiko; Hattori, Takanori; Sano-Furukawa, Asami; Endo, Naruki; Katayama, Yoshinori; Iizuka, Riko; Sato, Toyoto; Matsuo, Motoaki; Orimo, Shin-ichi; Aoki, Katsutoshi

2014-01-01

Hydrogen composition and occupation state provide basic information for understanding various properties of the metal–hydrogen system, ranging from microscopic properties such as hydrogen diffusion to macroscopic properties such as phase stability. Here the deuterization process of face-centred cubic Fe to form solid-solution face-centred cubic FeDx is investigated using in situ neutron diffraction at high temperature and pressure. In a completely deuterized specimen at 988 K and 6.3 GPa, deuterium atoms occupy octahedral and tetrahedral interstitial sites with an occupancy of 0.532(9) and 0.056(5), respectively, giving a deuterium composition x of 0.64(1). During deuterization, the metal lattice expands approximately linearly with deuterium composition at a rate of 2.21 Å3 per deuterium atom. The minor occupation of the tetrahedral site is thermally driven by the intersite movement of deuterium atoms along the ‹111› direction in the face-centred cubic metal lattice. PMID:25256789

Effect of the change in the load resistance on the high voltage pulse transformer of the intense electron-beam accelerators.

PubMed

Cheng, Xin-bing; Liu, Jin-liang; Qian, Bao-liang; Zhang, Yu; Zhang, Hong-bo

2009-11-01

A high voltage pulse transformer (HVPT) is usually used as a charging device for the pulse forming line (PFL) of intense electron-beam accelerators (IEBAs). Insulation of the HVPT is one of the important factors that restrict the development of the HVPT. Until now, considerable effort has been focused on minimizing high field regions to avoid insulation breakdown between windings. Characteristics of the HVPT have been widely discussed to achieve these goals, but the effects of the PFL and load resistance on HVPT are usually neglected. In this paper, a HVPT is used as a charging device for the PFL of an IEBA and the effect of the change in the load resistance on the HVPT of the IEBA is presented. When the load resistance does not match the wave impedance of the PFL, a high-frequency bipolar oscillating voltage will occur, and the amplitude of the oscillating voltage will increase with the decrease in the load resistance. The load resistance approximates to zero and the amplitude of the oscillating voltage is much higher. This makes it easier for surface flashover along the insulation materials to form and decrease the lifetime of the HVPT.

A study of dielectric breakdown along insulators surrounding conductors in liquid argon

DOE PAGES

Lockwitz, Sarah; Jostlein, Hans

2016-03-22

High voltage breakdown in liquid argon is an important concern in the design of liquid argon time projection chambers, which are often used as neutrino and dark matter detectors. We have made systematic measurements of breakdown voltages in liquid argon along insulators surrounding negative rod electrodes where the breakdown is initiated at the anode. The measurements were performed in an open cryostat filled with commercial grade liquid argon exposed to air, and not the ultra-pure argon required for electron drift. While not addressing all high voltage concerns in liquid argon, these measurements have direct relevance to the design of highmore » voltage feedthroughs especially for averting the common problem of flash-over breakdown. The purpose of these tests is to understand the effects of materials, of breakdown path length, and of surface topology for this geometry and setup. We have found that the only material-specific effects are those due to their permittivity. We have found that the breakdown voltage has no dependence on the length of the exposed insulator. Lastly, a model for the breakdown mechanism is presented that can help inform future designs.« less

Measurement of gluconeogenesis using glucose fragments and mass spectrometry after ingestion of deuterium oxide.

USDA-ARS?s Scientific Manuscript database

We report a new method to measure the fraction of glucose derived from gluconeogenesis using gas chromatography-mass spectrometry and positive chemical ionization. After ingestion of deuterium oxide by subjects, glucose derived from gluconeogenesis is labeled with deuterium. Our calculations of gluc...

Influence of traps on the deuterium behaviour in the low activation martensitic steels F82H and Batman

NASA Astrophysics Data System (ADS)

Serra, E.; Perujo, A.; Benamati, G.

1997-06-01

A time dependent permeation method is used to measure the permeability, diffusivity and solubility of deuterium in the low activation martensitic steels F82H and Batman. The measurements cover the temperature range from 373 to 743 K which includes the onset of deuterium trapping effects on diffusivity and solubility. The results are interpreted using a trapping model. The number of trap sites and their average energies for deuterium in F82H and Batman steels are determined.

Molecular dynamics simulations of hydrogen bombardment of tungsten carbide surfaces

NASA Astrophysics Data System (ADS)

Träskelin, P.; Juslin, N.; Erhart, P.; Nordlund, K.

2007-05-01

The interaction between energetic hydrogen and tungsten carbide (WC) is of interest both due to the use of hydrogen-containing plasmas in thin-film manufacturing and due to the presence of WC in the divertor of fusion reactors. In order to study this interaction, we have carried out molecular dynamics simulations of the low-energy bombardment of deuterium impinging onto crystalline as well as amorphous WC surfaces. We find that prolonged bombardment leads to the formation of an amorphous WC surface layer, regardless of the initial structure of the WC sample. Loosely bound hydrocarbons, which can erode by swift chemical sputtering, are formed at the surface. Carbon-terminated surfaces show larger sputtering yields than tungsten-terminated surfaces. In both cumulative and noncumulative simulations, C is seen to sputter preferentially. Implications for mixed material erosion in ITER are discussed.

Formation of a dual-stage pinch-accelerator in a Z-pinch (plasma focus) device

NASA Astrophysics Data System (ADS)

Behbahani, R. A.; Hirose, A.; Xiao, C.

2018-01-01

A novel dense plasma focus configuration with two separate concentric current sheet run-down regions has been demonstrated to produce several consecutive plasma focusing events. In a proof-of-principle experiment on a low-energy plasma focus device, the measured tube voltages and discharge current have been explained by using circuit analyses of the device. Based on the calculated plasma voltages the occurrence of flash-over phase, axial phase, and compression phase has been discussed. The electrical signals along with the calculated plasma voltages suggest the occurrence of several focusing events in the new structure.

Comparative Study of Hydrogen- and Deuterium-Induced Degradation of Ferroelectric (Pb,La)(Zr,Ti)O3 Capacitors Using Time-of-Flight Secondary Ion Measurement.

PubMed

Takada, Yoko; Okamoto, Naoki; Saito, Takeyasu; Yoshimura, Takeshi; Fujimura, Norifumi; Higuchi, Koji; Kitajima, Akira; Shishido, Rie

2016-10-01

Ferroelectric (Pb,La)(Zr,Ti)O 3 (PLZT) capacitors were fabricated with Pt, Al:ZnO (AZO), or Sn:In 2 O 3 (ITO) top electrodes. Hydrogen- or deuterium-induced degradation was investigated for the three capacitors by annealing in a 3% H 2 /balance N 2 or 3% D 2 /balance N 2 ambient environment at 200 °C and 1 torr. The remnant polarization of all capacitors decreased after annealing in both H 2 and D 2 ambient after 45 min, and the remnant polarization of the Pt/PLZT/Pt capacitor significantly decreased after 45-min annealing compared with that of the AZO/PLZT/Pt and ITO/PLZT/Pt capacitors, even though the initial remnant polarization for the Pt/PLZT/Pt capacitor was larger. Time-of-flight secondary ion mass spectrometry showed slight differences in hydrogen content for the three different capacitors after H 2 annealing. In contrast, the deuterium content of the Pt/PLZT/Pt and AZO/PLZT/Pt or ITO/PLZT/PT capacitors was significantly different after deuterium annealing. Deuterium depth profiles for the Pt/PLZT/Pt capacitor after annealing showed that deuterium conformally exists in the PLZT layer of the Pt/PLZT/Pt capacitor, and deuterium accumulation under the Pt bottom electrode was also observed. This result suggests that diffusion of deuterium in Pt was much higher than that in PLZT. AZO and ITO top electrodes could act as a hydrogen barrier layer for ferroelectric films.

Displacement damage dose and implantation temperature effects on the trapping and release of deuterium implanted into SiC

NASA Astrophysics Data System (ADS)

Muñoz, P.; García-Cortés, I.; Sánchez, F. J.; Moroño, A.; Malo, M.; Hodgson, E. R.

2017-09-01

Radiation damage to flow channel insert (FCI) materials is an important issue for the concept of dual-coolant blanket development in future fusion devices. Silicon Carbide (SiC) is one of the most suitable materials for FCI. Because of the severe radiation environment and exposure to tritium during operation it is of fundamental importance to study hydrogen isotope trapping and release in these materials. Here the trapping, detrapping, and diffusion of deuterium implanted into SiC is studied in correlation with pre- and post-damage induced under different conditions. For this, SiC samples are pre-damaged with 50 keV Ne+ ions at different temperatures (20, 200, 450, 700 °C) to different damage doses (1, 3.6, 7 dpa). Next, deuterium is introduced into the samples at 450 °C by ion implantation at 7 keV. The implanted deuterium retained in the sample is analysed using secondary ion mass spectrometry (SIMS) and thermo-stimulated desorption (TSD) measurements. The results indicate that with increasing neon damage dose, the maximum deuterium desorption occurs at higher temperatures. In contrast, when increasing neon implantation temperature for a fixed dose, the maximum deuterium desorption release temperature decreases. It is interpreted that the neon bombardment produces thermally stable traps for hydrogen isotopes and the stability of this damage increases with neon pre-implantation dose. A decrease of the trapping of implanted deuterium is also observed to occur due to damage recovery by thermal annealing during pre-implantation at the higher temperatures. Finally, direct particle bombardment induced deuterium release is also observed.

Reduced deuterium retention in simultaneously damaged and annealed tungsten

DOE PAGES

Simmonds, M. J.; Wang, Y. Q.; Barton, J. L.; ...

2017-06-24

Deuterium (D) retention in polycrystalline tungsten (W) with copper (Cu) ion damage concurrently produced at elevated surface temperature is investigated in this paper. An in situ heated stage held W samples at a controlled temperature up to 1243 K, which were subjected to displacement damage produced by 3.4 MeV Cu ions. D retention is subsequently explored by exposure of the W samples held at 383 K to a D 2 plasma ion fluence of 10 24 D +/m 2. Nuclear reaction analysis (NRA), utilizing the D( 3He,p) 4He nuclear reaction, is used to probe the D concentration in the nearmore » surface up to 6 μm. Thermal desorption spectroscopy (TDS) is used to measure outgassed HD and D 2 molecules to determine the bulk D concentration. Both NRA and TDS measure a significant reduction in D retention for samples damaged at elevated temperature. TDS quantitatively shows that the lowest energy trap remains largely unaffected while higher energy traps, induced by Cu ions, are annealed and approach intrinsic concentrations as the temperature during ion damage approaches 1243 K. Finally, analysis of TDS data yields an activation energy of (0.10 ± 0.02) eV for recovery of ion-damage induced traps at elevated temperature.« less

Reduced deuterium retention in simultaneously damaged and annealed tungsten

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simmonds, M. J.; Wang, Y. Q.; Barton, J. L.

Deuterium (D) retention in polycrystalline tungsten (W) with copper (Cu) ion damage concurrently produced at elevated surface temperature is investigated in this paper. An in situ heated stage held W samples at a controlled temperature up to 1243 K, which were subjected to displacement damage produced by 3.4 MeV Cu ions. D retention is subsequently explored by exposure of the W samples held at 383 K to a D 2 plasma ion fluence of 10 24 D +/m 2. Nuclear reaction analysis (NRA), utilizing the D( 3He,p) 4He nuclear reaction, is used to probe the D concentration in the nearmore » surface up to 6 μm. Thermal desorption spectroscopy (TDS) is used to measure outgassed HD and D 2 molecules to determine the bulk D concentration. Both NRA and TDS measure a significant reduction in D retention for samples damaged at elevated temperature. TDS quantitatively shows that the lowest energy trap remains largely unaffected while higher energy traps, induced by Cu ions, are annealed and approach intrinsic concentrations as the temperature during ion damage approaches 1243 K. Finally, analysis of TDS data yields an activation energy of (0.10 ± 0.02) eV for recovery of ion-damage induced traps at elevated temperature.« less

Deuterium Labeling Strategies for Creating Contrast in Structure-Function Studies of Model Bacterial Outer Membranes Using Neutron Reflectometry.

PubMed

Le Brun, Anton P; Clifton, Luke A; Holt, Stephen A; Holden, Peter J; Lakey, Jeremy H

2016-01-01

Studying the outer membrane of Gram-negative bacteria is challenging due to the complex nature of its structure. Therefore, simplified models are required to undertake structure-function studies of processes that occur at the outer membrane/fluid interface. Model membranes can be created by immobilizing bilayers to solid supports such as gold or silicon surfaces, or as monolayers on a liquid support where the surface pressure and fluidity of the lipids can be controlled. Both model systems are amenable to having their structure probed by neutron reflectometry, a technique that provides a one-dimensional depth profile through a membrane detailing its thickness and composition. One of the strengths of neutron scattering is the ability to use contrast matching, allowing molecules containing hydrogen and those enriched with deuterium to be highlighted or matched out against the bulk isotopic composition of the solvent. Lipopolysaccharides, a major component of the outer membrane, can be isolated for incorporation into model membranes. Here, we describe the deuteration of lipopolysaccharides from rough strains of Escherichia coli for incorporation into model outer membranes, and how the use of deuterated materials enhances structural analysis of model membranes by neutron reflectometry. © 2016 Elsevier Inc. All rights reserved.

The Effects of Deuterium Oxide on Certain Microorganisms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Giovanni, Rosalie

1960-11-01

The growth of several strains of E. coli and B. subtilis was inhibited by the presence of D 2O; the degree of inhibition exhibited by each strain was specific. The addition of 0.5 per cent NaCl to the D 2O media decreased the inhibition of growth. A deuterium-resistant mutant was obtained from one strain of E.coli. The incorporation of deuterium induces not only phenotypic but also genotypic changes in microorganisms. The effects induced by deuterium depend, however, on the genotype of the strain. The isotope appears to be mutagenic for some strains and some loci but not for others. Variousmore » types of forward mutations were obtained in some of the bacterial strains tested and the frequency of backward mutation was increased in two strains exposed to deuterium. Thymine containing deuterium, possibly in its methyl group, is not capable of inducing any detectable changes in a thymine requiring mutant. Cells, grown in D 2O media and subsequently washed and irradiated in H 2O saline, are more sensitive to ultraviolet irradiation than control cells.« less

First Measurements of Deuterium-Tritium and Deuterium-Deuterium Fusion Reaction Yields in Ignition-Scalable Direct-Drive Implosions.

PubMed

Forrest, C J; Radha, P B; Knauer, J P; Glebov, V Yu; Goncharov, V N; Regan, S P; Rosenberg, M J; Sangster, T C; Shmayda, W T; Stoeckl, C; Gatu Johnson, M

2017-03-03

The deuterium-tritium (D-T) and deuterium-deuterium neutron yield ratio in cryogenic inertial confinement fusion (ICF) experiments is used to examine multifluid effects, traditionally not included in ICF modeling. This ratio has been measured for ignition-scalable direct-drive cryogenic DT implosions at the Omega Laser Facility [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)OPCOB80030-401810.1016/S0030-4018(96)00325-2] using a high-dynamic-range neutron time-of-flight spectrometer. The experimentally inferred yield ratio is consistent with both the calculated values of the nuclear reaction rates and the measured preshot target-fuel composition. These observations indicate that the physical mechanisms that have been proposed to alter the fuel composition, such as species separation of the hydrogen isotopes [D. T. Casey et al., Phys. Rev. Lett. 108, 075002 (2012)PRLTAO0031-900710.1103/PhysRevLett.108.075002], are not significant during the period of peak neutron production in ignition-scalable cryogenic direct-drive DT implosions.

[Influence of deuterium depleted water on freeze-dried tissue isotopic composition and morphofunctional body performance in rats of different generations].

PubMed

Dzhimak, S S; Baryshev, M G; Basov, A A; Timakov, A A

2014-01-01

The influence of deuterium depleted water on the body of different rats generations was investigated in physiological conditions. As a result of this study it was established that the most significant and rapid reduction in D/H equilibrium was observed in plasma (by 36.2%), and lyophilized kidney tissues (by 15.8%). Less pronounced deuterium decrease was characteristic of liver tissue (9.3%) and heart (8.5%). Stabilization of the isotopic exchange reaction rate was fixed in the blood and tissues of rats, starting from the second generation. At the same time when deuterium depleted water (40 ppm) was used in dietary intake, the change in morphological and functional parameters in laboratory animals associated with the processes of adaptation to the effects of substress isotopic D/H gradient was also noted. The study shows that modification of:only drinking water intake regime can't significantly change the deuterium content in tissues of metabolically active organs, because of the concurrent deuterium receipt in food substances of plant and animal origin.

Structure and reaction properties of thin Al films deposited on Ni(110)

NASA Astrophysics Data System (ADS)

Hahn, Peter; Bertino, Massimo F.; Toennies, J. Peter; Ritter, Michael; Weiss, Werner

1998-09-01

A variety of experimental techniques, including scanning tunneling microscopy (STM) and thermal desorption spectroscopy (TDS) have been used to investigate the structure and reaction properties of thin Al films on Ni(110) as a model for technical Raney nickel catalysts. The measurements show that Al grows by the Volmer-Weber growth mode, with Al islands reaching a height of 30 Å before the first Al layer is completed. On exposure to deuterium the TDS spectra indicate that the addition of Al produces a new deuterium chemisorption state with a desorption energy which decreases from 27 to 14 kJ/mol with increasing deuterium coverage. This new bound state is attributed to deuterium atoms bound to adsorption sites in the vicinity of Al islands. Thermal desorption measurements also reveal that the deuterium initial sticking coefficient S0 decreases with Al coverage. The results can be explained by a simple model which shows that for low Al coverages each Al island inhibits deuterium dissociation in a region which is about three times larger than the island area.

Direct measurements and comparisons between deuterium and impurity rotation and density profiles in the H-mode steep gradient region on DIII-D

NASA Astrophysics Data System (ADS)

Haskey, S. R.; Grierson, B. A.; Chrystal, C.; Stagner, L.; Burrell, K.; Groebner, R. J.; Kaplan, D. H.; Nazikian, R.

2016-10-01

The recently commissioned edge deuterium charge exchange recombination (CER) spectroscopy diagnostic on DIII-D is providing direct measurements of the deuterium rotation, temperature, and density in H-mode pedestals. The deuterium temperature and temperature scale length can be 50 % lower than the carbon measurement in the gradient region of the pedestal, indicating that the ion pedestal pressure can deviate significantly from that inferred from carbon CER. In addition, deuterium exhibits a larger toroidal rotation in the co-Ip direction near the separatrix compared with the carbon. These differences are qualitatively consistent with theory-based models that identify thermal ion orbit loss across the separatrix as a source of intrinsic angular momentum. The first direct measurements of the deuterium density pedestal profile show an inward shift of the impurity pedestal compared with the main ions, validating neoclassical predictions from the XGC0 code. Work supported by the U.S. DOE under DE-FC02-04ER54698 and DE-AC02-09CH11466.

Improved Hot Carrier Reliability Characteristics of Metal Oxide Semiconductor Field Effect Transistors with High-k Gate Dielectric by Using High Pressure Deuterium Post Metallization Annealing

NASA Astrophysics Data System (ADS)

Park, Hokyung; Choi, Rino; Lee, Byoung Hun; Hwang, Hyunsang

2007-09-01

High pressure deuterium annealing on the hot carrier reliability characteristics of HfSiO metal oxide semiconductor field effect transistor (MOSFET) was investigated. Comparing with the conventional forming gas (H2/Ar=10%/96%, 480 °C, 30 min) annealed sample, MOSFET annealed in 5 atm pure deuterium ambient at 400 °C showed the improvement of linear drain current, reduction of interface trap density, and improvement of the hot carrier reliability characteristics. These improvements can be attributed to the effective passivation of the interface trap site after high pressure annealing and heavy mass effect of deuterium. These results indicate that high pressure pure deuterium annealing can be a promising process for improving device performance as well as hot carrier reliability, together.

X-Ray-induced Deuterium Enrichment of N-rich Organics in Protoplanetary Disks: An Experimental Investigation Using Synchrotron Light

NASA Astrophysics Data System (ADS)

Gavilan, Lisseth; Remusat, Laurent; Roskosz, Mathieu; Popescu, Horia; Jaouen, Nicolas; Sandt, Christophe; Jäger, Cornelia; Henning, Thomas; Simionovici, Alexandre; Lemaire, Jean Louis; Mangin, Denis; Carrasco, Nathalie

2017-05-01

The deuterium enrichment of organics in the interstellar medium, protoplanetary disks, and meteorites has been proposed to be the result of ionizing radiation. The goal of this study is to simulate and quantify the effects of soft X-rays (0.1-2 keV), an important component of stellar radiation fields illuminating protoplanetary disks, on the refractory organics present in the disks. We prepared tholins, nitrogen-rich organic analogs to solids found in several astrophysical environments, e.g., Titan’s atmosphere, cometary surfaces, and protoplanetary disks, via plasma deposition. Controlled irradiation experiments with soft X-rays at 0.5 and 1.3 keV were performed at the SEXTANTS beamline of the SOLEIL synchrotron, and were immediately followed by ex-situ infrared, Raman, and isotopic diagnostics. Infrared spectroscopy revealed the preferential loss of singly bonded groups (N-H, C-H, and R-N≡C) and the formation of sp3 carbon defects with signatures at ˜1250-1300 cm-1. Raman analysis revealed that, while the length of polyaromatic units is only slightly modified, the introduction of defects leads to structural amorphization. Finally, tholins were measured via secondary ion mass spectrometry to quantify the D, H, and C elemental abundances in the irradiated versus non-irradiated areas. Isotopic analysis revealed that significant D-enrichment is induced by X-ray irradiation. Our results are compared to previous experimental studies involving the thermal degradation and electron irradiation of organics. The penetration depth of soft X-rays in μm-sized tholins leads to volume rather than surface modifications: lower-energy X-rays (0.5 keV) induce a larger D-enrichment than 1.3 keV X-rays, reaching a plateau for doses larger than 5 × 1027 eV cm-3. Synchrotron fluences fall within the expected soft X-ray fluences in protoplanetary disks, and thus provide evidence of a new non-thermal pathway to deuterium fractionation of organic matter.

Observations of interstellar hydrogen and deuterium toward Alpha Centauri A

NASA Technical Reports Server (NTRS)

Landsman, W. B.; Henry, R. C.; Moos, H. W.; Linsky, J. L.

1984-01-01

A composite profile is presented of the Ly-alpha emission line of Alpha Cen A, obtained from 10 individual spectra with the high-resolution spectrograph aboard the International Ultraviolet Explorer (IUE) satellite. There is excellent overall agreement with two previous Copernicus observations. Interstellar deuterium is detected, and a lower limit is set on the deuterium to hydrogen ratio of nDI/nHI greater than 8 x 10 to the -6th. In addition, the deuterium bulk velocity appears blueshifted by 8 + or - 2 km/s with respect to interstellar hydrogen, suggesting a nonuniform medium along the line of sight.

Results of an attempt to measure increased rates of the reaction D-2 + D-2 yields He-3 + n in a nonelectrochemical cold fusion experiment

NASA Technical Reports Server (NTRS)

Fralick, Gustave C.; Decker, Arthur J.; Blue, James W.

1989-01-01

An experiment was performed to look for evidence of deuterium fusion in palladium. The experiment, which involved introducing deuterium into the palladium filter of a hydrogen purifier, was designed to detect neutrons produced in the reaction D-2 + D-2 yields He-3 + n as well as heat production. The neutron counts for deuterium did not differ significantly from background or from the counts for a hydrogen control. Heat production was detected when deuterium, but not hydrogen, was pumped from the purifier.

A Reexamination of Deuterium Fractionation on Mars

NASA Astrophysics Data System (ADS)

Pathare, A.; Paige, D. A.

1997-07-01

The ratio of deuterium to hydrogen in the Martian atmosphere is enhanced by a factor of 5 with respect to the terrestrial value, probably due to fractionation associated with thermal Jeans escape from the top of the atmosphere. Theoretical analyses of the relative efficiency of H and D escape have suggested that the deuterium enrichment implies Mars has outgassed the vast majority of its H2O and that the Martian atmosphere is presently not exchanging water with a juvenile reservoir. However, measurements of high and variable D/H values within hydrous minerals in SNC meteorites strongly suggest that mixing between the atmosphere and juvenile water has taken place. Furthermore, the lack of any observed enrichment of atmospheric (18) O with respect to (16) O, in spite of fractionating nonthermal escape mechanisms, indicates buffering by some juvenile source of oxygen, most probably in the form of a surface or subsurface reservoir of water. We propose that this apparent paradox in the interpretation of isotopic hydrogen and oxygen fractionation --or lack thereof-- can be resolved by re-examining the standard model of deuterium fractionation efficiency on Mars. Specifically, we demonstrate the importance of using upper atmospheric temperatures more representative of the range experienced by the Martian exosphere over the course of the solar cycle. Preliminary calculations involving changes in effusion velocity and diffusive separation as a function of exospheric temperature indicate that incorporating these more representative lower exospheric temperatures will reduce the relative efficiency of D escape, in which case the observed enrichment of deuterium can indeed result from exchange with a juvenile source of water. We are in the process of confirming these computations with a one-dimensional upper atmospheric photochemical model that considers the effects of changing solar activity and exospheric temperature on ionospheric composition. If our initial calculations are correct, and the relative efficiency of D escape is low enough to produce the observed D enrichment by exchange with a juvenile reservoir, then attempts to use the present value of atmospheric D/H to infer the total water outgassed by Mars over billions of years would be in error, since the atmospheric D/H would approach its present value in less than a million years of continual exposure to juvenile water.

Plasma focus sources: Supplement to the Neutron Resonance Radiography Workshop proceedings

NASA Astrophysics Data System (ADS)

Nardi, Vittorio; Brzosko, Jan

1989-01-01

Since their discovery, plasma focus discharges have been recognized as very intense pulsed sources of deuterium-deuterium (D-D) or deuterium-tritium (D-T) fusion-reaction neutrons, with outstanding capabilities. Specifically, the total neutron emission/shot, Y (sub n), and the rate of neutron emission, Y (sub n), of an optimized plasma focus (PF) are higher than the corresponding quantities observed in any other type of pinched discharge at the same level of powering energy W (sub 0). Recent developments have led to the concept and experimental demonstration of an Advanced Plasma Focus System (APF) that consists of a Mather-geometry plasma focus in which field distortion elements (FDEs) are inserted in the inter-electrode gap for increasing the neutron yield/shot, Y (sub n). The FDE-induced redistribution of the plasma current increases Y (sub n) by a factor approximate to or greater than 5 to 10 above the value obtained without FDEs under otherwise identical conditions of operation of the plasma focus. For example, an APF that is fed by a fast capacitor bank with an energy, W (sub 0) = 6 kJ, and voltage, V (sub 0) = 16.5 kV provides Y (sub n) congruent to 4 x 10 to the 9th D-D neutrons/shot (pure D2 filling) and Y (sub n) = 4 x 10 to the 11th D-T neutrons/shot (filling is 50 pct deuterium and 50 pct tritium). The FDE-induced increase of Y (sub n) for fixed values of (W sub 0, V sub 0), the observed scaling law Y (sub n) proportional to W (sub 0) squared for optimized plasma focus systems, and our experience with neutron scattering in bulk objects lead us to the conclusion that we can use an APF as a source of high-intensity neutron pulses (10 to the 14th n/pulse) in the field off neutron radiography (surface and bulk) with a nanosecond or millisecond time resolution.

The Production of Hadrons in Muon Scattering on Deuterium and Xenon Nuclei at 480-GeV (in German)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Soldner-Rembold, Stefan

1992-01-01

For the present thesis the hadronic final states of 6309 muon-deuterium events and 2064 muon-xenon events in the kinematical range Q 2>1 (GeV/c) 2, x>0.002, 0.1< y<0.85, 8< W<30 GeV, and θ>3.5 mrad were studied. The multiplicity distributions of the muon-deuterium events and the muon-xenon events were described by means of the negative binomial distribution in intervals of the c.m. energy W. The two parameters anti n (mean multiplicity) and 1/k show for the muon-deuterium events a linear dependence on ln W2. The mean multiplicity anti n on xenon (anti n=10.43±0.19) is distinctly higher than on deuterium (anti n=7.76±0.07). Themore » rapidity distributions of the positively charged and the negatively charged hadrons from muon-deuterium events are very well described by the Monte-Carlo program LUND. In the two-particle rapidity correlation both short-range and long-range correlations can be detected. The two-particle rapidity correlation in the xenon data are different from the deuterium data in the backward range. This difference indicates that the intranuclear cascade takes place in a limited range of small rapidities - relatively independently on the residual fragmentation process.« less

Observations of Highly Variable Deuterium in the Martian Upper Atmosphere

NASA Astrophysics Data System (ADS)

Clarke, John T.; Mayyasi-Matta, Majd A.; Bhattacharyya, Dolon; Chaufray, Jean-Yves; Chaffin, Michael S.; Deighan, Justin; Schneider, Nicholas M.; Jain, Sonal; Jakosky, Bruce

2017-10-01

One of the key pieces of evidence for historic high levels of water on Mars is the present elevated ratio of deuterium/hydrogen (D/H) in near-surface water. This can be explained by the loss of large amounts of water into space, with the lighter H atoms escaping faster than D atoms. Understanding the specific physical processes and controlling factors behind the present escape of H and D is the key objective of the MAVEN IUVS echelle channel. This knowledge can then be applied to an accurate extrapolation back in time to understand the water history of Mars. Observations of D in the martian upper atmosphere over the first martian year of the MAVEN mission have shown highly variable amounts of D, with a short-lived maximum just after perihelion and during southern summer. The timing and nature of this increase provide constraints on its possible origin. These results will be presented and compared with other measurements of the upper atmosphere of Mars.

Deuterium trapping in the carbon-silicon co-deposition layers prepared by RF sputtering in D2 atmosphere

NASA Astrophysics Data System (ADS)

Zhang, Hongliang; Zhang, Weiyuan; Su, Ranran; Tu, Hanjun; Shi, Liqun; Hu, Jiansheng

2018-04-01

Deuterated carbon-silicon layers co-deposited on graphite and silicon substrates by radio frequency magnetron sputtering in pure D2 plasma were produced to study deuterium trapping and characteristics of the C-Si layers. The C-Si co-deposited layers were examined by ion beam analysis (IBA), Raman spectroscopy (RS), infrared absorption (IR) spectroscopy, thermal desorption spectroscopy (TDS) and scanning electron microscopy (SEM). It was found that the growth rate of the C-Si co-deposition layer decreased with increasing temperature from 350 K to 800 K, the D concentration and C/Si ratios increased differently on graphite and silicon substrates. TDS shows that D desorption is mainly as D2, HD, HDO, CD4, and C2D4 and release peaks occurred at temperatures of less than 900 K. RS and IR analysis reveal that the structure of the C-Si layers became more disordered with increasing temperatures. Rounded areas of peeling with 1-2 μm diameters were observed on the surface.

Impact of temperature during He+ implantation on deuterium retention in tungsten, tungsten with carbon deposit and tungsten carbide

NASA Astrophysics Data System (ADS)

Oya, Yasuhisa; Sato, Misaki; Li, Xiaochun; Yuyama, Kenta; Fujita, Hiroe; Sakurada, Shodai; Uemura, Yuki; Hatano, Yuji; Yoshida, Naoaki; Ashikawa, Naoko; Sagara, Akio; Chikada, Takumi

2016-02-01

Temperature dependence on deuterium (D) retention for He+ implanted tungsten (W) was studied by thermal desorption spectroscopy (TDS) to evaluate the tritium retention behavior in W. The activation energies were evaluated using Hydrogen Isotope Diffusion and Trapping (HIDT) simulation code and found to be 0.55 eV, 0.65 eV, 0.80 eV and 1.00 eV. The heating scenarios clearly control the D retention behavior and, dense and large He bubbles could work as a D diffusion barrier toward the bulk, leading to D retention enhancement at lower temperature of less than 430 K, even if the damage was introduced by He+ implantation. By comparing the D retention for W, W with carbon deposit and tungsten carbide (WC), the dense carbon layer on the surface enhances the dynamic re-emission of D as hydrocarbons, and induces the reduction of D retention. However, by He+ implantation, the D retention was increased for all the samples.

Observations of electron heating during 28 GHz microwave power application in proto-MPEX

DOE PAGES

Biewer, Theodore M.; Bigelow, Tim S.; Caneses Marin, Juan F.; ...

2018-02-01

The Prototype Material Plasma Exposure Experiment at the Oak Ridge National Laboratory utilizes a variety of power systems to generate and deliver a high heat flux plasma onto the surface of material targets. In the experiments described here, a deuterium plasma is produced via a ~100 kW, 13.56 MHz RF helicon source, to which ~20 kW of 28 GHz microwave power is applied. The electron density and temperature profiles are measured using a Thomson scattering (TS) diagnostic, and indicate that the electron density is centrally peaked. In the core of the plasma column, the electron density is higher than themore » cut-off density (~0.9 × 1019 m -3) for the launched mixture of X- and O-mode electron cyclotron heating waves to propagate. TS measurements indicate electron temperature increases from ~5 eV to ~20 eV during 28 GHz power application when the neutral deuterium pressure is reduced below 0.13 Pa (~1 mTorr.).« less

Observations of electron heating during 28 GHz microwave power application in proto-MPEX

NASA Astrophysics Data System (ADS)

Biewer, T. M.; Bigelow, T. S.; Caneses, J. F.; Diem, S. J.; Green, D. L.; Kafle, N.; Rapp, J.; Proto-MPEX Team

2018-02-01

The Prototype Material Plasma Exposure Experiment at the Oak Ridge National Laboratory utilizes a variety of power systems to generate and deliver a high heat flux plasma onto the surface of material targets. In the experiments described here, a deuterium plasma is produced via a ˜100 kW, 13.56 MHz RF helicon source, to which ˜20 kW of 28 GHz microwave power is applied. The electron density and temperature profiles are measured using a Thomson scattering (TS) diagnostic, and indicate that the electron density is centrally peaked. In the core of the plasma column, the electron density is higher than the cut-off density (˜0.9 × 1019 m-3) for the launched mixture of X- and O-mode electron cyclotron heating waves to propagate. TS measurements indicate electron temperature increases from ˜5 eV to ˜20 eV during 28 GHz power application when the neutral deuterium pressure is reduced below 0.13 Pa (˜1 mTorr.).

Protein Structural Analysis via Mass Spectrometry-Based Proteomics

PubMed Central

Artigues, Antonio; Nadeau, Owen W.; Rimmer, Mary Ashley; Villar, Maria T.; Du, Xiuxia; Fenton, Aron W.; Carlson, Gerald M.

2017-01-01

Modern mass spectrometry (MS) technologies have provided a versatile platform that can be combined with a large number of techniques to analyze protein structure and dynamics. These techniques include the three detailed in this chapter: 1) hydrogen/deuterium exchange (HDX), 2) limited proteolysis, and 3) chemical crosslinking (CX). HDX relies on the change in mass of a protein upon its dilution into deuterated buffer, which results in varied deuterium content within its backbone amides. Structural information on surface exposed, flexible or disordered linker regions of proteins can be achieved through limited proteolysis, using a variety of proteases and only small extents of digestion. CX refers to the covalent coupling of distinct chemical species and has been used to analyze the structure, function and interactions of proteins by identifying crosslinking sites that are formed by small multi-functional reagents, termed crosslinkers. Each of these MS applications is capable of revealing structural information for proteins when used either with or without other typical high resolution techniques, including NMR and X-ray crystallography. PMID:27975228

D 2 and DT Liquid-Layer Target Shots on NIF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Walters, Curtis; Alger, Ethan; Bhandarkar, Suhas

Experiments at the National Ignition Facility (NIF) using targets containing a Deuterium-Tritium (DT) fuel layer have, until recently, required that a high-quality layer of solid deuterium-tritium (herein referred to as an "ice-layer") be formed in the capsule. The development of a process to line the inner surface of a target capsule with a foam layer of a thickness that is typical of icelayers has resulted in the ability to field targets with liquid layers wetting the foam. Successful fielding of liquid-layer targets on NIF required not only a foam lined capsule, but also changes to the capsule filling process andmore » the manner with which the inventory is maintained in the capsule. Additionally, changes to target heater power and the temperature drops across target components were required in order to achieve the desired range of shot temperatures. These changes, and the target's performance during four target shots on NIF will be discussed.« less

Kinetic and Mechanistic Studies of the Deuterium Exchange in Classical Keto-Enol Tautomeric Equilibrium Reactions

ERIC Educational Resources Information Center

Nichols, Michael A.; Waner, Mark J.

2010-01-01

An extension of the classic keto-enol tautomerization of beta-dicarbonyl compounds into a kinetic analysis of deuterium exchange is presented. It is shown that acetylacetone and ethyl acetoacetate undergo nearly complete deuterium exchange of the alpha-methylene carbon when dissolved in methanol-d[subscript 4]. The extent of deuteration may be…

Vanadium hydride deuterium-tritium generator

DOEpatents

Christensen, Leslie D.

1982-01-01

A pressure controlled vanadium hydride gas generator to provide deuterium-tritium gas in a series of pressure increments. A high pressure chamber filled with vanadium-deuterium-tritium hydride is surrounded by a heater which controls the hydride temperature. The heater is actuated by a power controller which responds to the difference signal between the actual pressure signal and a programmed pressure signal.

THE BIOLOGY OF DEUTERIUM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Katz, J.J.; Crespi, H.L.; Finkel, A.J.

1958-10-31

g been noted, but the full scope and nature of these effects still remain largely unexplored. Early work was greatly hampered by the difficulties of obtaining deuterium but the development of a vast nuclear energy technology has made deuterium available on a larghe scale. It has now become opportune to undertake comprehensive reports work undertaken on algae, fungi, bacteria, and mammals. Mice will tolerate up to about 40 per cent D/sub 2/O in the drinking water for at least four months; of about 30 per cent heavy water. When deuteration is into various tissues and organs to the amount ofmore » from 40 to 50 per cent of the deuterium in the body fluids. 25 atom per cent, for as long as 12 months without obcal effects of deuterium is the kinetic isotpe effect. In general, bonds to deuterium react less readily than bonds to hydrogen; in consequence, reaction reates are decreased, and a depression in tissue metabolism should result. At concentrations about 30 atom per cen deuterium mice and rats show weakness, neutrmuscular por and death Since neoplastic cells metabolize rapidly, presumably these should be particularly sensitive to the effects of deuteration. Deuteration of host mice resulted in reduced growth rates of injected Krebs-2 ascites tumors and of inoculated P-1534 lymphatic leukemia. The general effects of deuterium on growth has been Chlorella vulgaris and Scenedesmus obliquus, have been have been harvested that yield water of combustion containing more than 90 atom per cent deuterium. The e were altered by deuteration. The fungi Penicillium notatum and Aspergillus fonsecaeus have been grown in media containing various concentrations of D/sub 2/O up to 99.6 per cent, and here, too, morphology, sporulation, pigment production, and growth rate were all affected by deuteration. The results obtained with algae clearly indicate the feasibility of producing fully deuterated compounds of biological significance by biosynthetic procedures. Bacterial studies on Group C hemolytic streptococci, Type I pnemococci, Mycobacterium tuberculosis and M.phlei, and Escherichia coli showed that the growth rates were diminished with elevation of the D/.sub 2/O concentration above 50 per cent and that cessation of growth uniformly occurred at D/sub 2/O levels greater than 90 per cent. Deuterium may also be utilized in the study of metabolism by the administration of deuterated essential metabolites. Experiments are described wherein fungi have been grown on glucose in which the hydrogen on carbon-1 (D-glucose-d/sub 1/) has been completely replaced by deuterium. (auth)« less

Pharmaco-thermodynamics of deuterium-induced oedema in living rat brain via 1H2O MRI: implications for boron neutron capture therapy of malignant brain tumours

NASA Astrophysics Data System (ADS)

Medina, Daniel C.; Li, Xin; Springer, Charles S., Jr.

2005-05-01

In addition to its common usage as a tracer in metabolic and physiological studies, deuterium possesses anti-tumoural activity and confers protection against γ-irradiation. A more recent interest in deuterium emanates from the search for alternatives capable of improving neutron penetrance whilst reducing healthy tissue radiation dose deposition in boron neutron capture therapy of malignant brain tumours. Despite this potential clinical application, deuterium induces brain oedema, which is detrimental to neutron capture therapy. In this study, five adult male rats were titrated with deuterated drinking water while brain oedema was monitored via water proton magnetic resonance imaging. This report concludes that deuterium, as well as deuterium-induced brain oedema, possesses a uniform brain bio-distribution. At a steady-state blood fluid deuteration value of 16%, when the deuterium isotope fraction in drinking water was 25%, a mean oedematous volume change of 9 ± 2% (p-value <0.001) was observed in the rat brain—this may account for neurological and behavioural abnormalities found in mammals drinking highly deuterated water. In addition to characterizing the pharmaco-thermodynamics of deuterium-induced oedema, this report also estimates the impact of oedema on thermal neutron enhancement and effective dose reduction factors using simple linear transport calculations. While body fluid deuteration enhances thermal neutron flux penetrance and reduces dose deposition, oedema has the opposite effect because it increases the volume of interest, e.g., the brain volume. Thermal neutron enhancement and effective dose reduction factors could be reduced by as much as ~10% in the presence of a 9% water volume increase (oedema). All three authors have contributed equally to this work.

Measurement of gluconeogenesis using glucose fragments and mass spectrometry after ingestion of deuterium oxide.

PubMed

Chacko, Shaji K; Sunehag, Agneta L; Sharma, Susan; Sauer, Pieter J J; Haymond, Morey W

2008-04-01

We report a new method to measure the fraction of glucose derived from gluconeogenesis using gas chromatography-mass spectrometry and positive chemical ionization. After ingestion of deuterium oxide by subjects, glucose derived from gluconeogenesis is labeled with deuterium. Our calculations of gluconeogenesis are based on measurements of the average enrichment of deuterium on carbon 1, 3, 4, 5, and 6 of glucose and the deuterium enrichment in body water. In a sample from an adult volunteer after ingestion of deuterium oxide, fractional gluconeogenesis using the "average deuterium enrichment method" was 48.3 +/- 0.5% (mean +/- SD) and that with the C-5 hexamethylenetetramine (HMT) method by Landau et al. (Landau BR, Wahren J, Chandramouli V, Schumann WC, Ekberg K, Kalhan SC; J Clin Invest 98: 378-385, 1996) was 46.9 +/- 5.4%. The coefficient of variation of 10 replicate analyses using the new method was 1.0% compared with 11.5% for the C-5 HMT method. In samples derived from an infant receiving total parenteral nutrition, fractional gluconeogenesis was 13.3 +/- 0.3% using the new method and 13.7 +/- 0.8% using the C-5 HMT method. Fractional gluconeogenesis measured in six adult volunteers after 66 h of continuous fasting was 83.7 +/- 2.3% using the new method and 84.2 +/- 5.0% using the C-5 HMT method. In conclusion, the average deuterium enrichment method is simple, highly reproducible, and cost effective. Furthermore, it requires only small blood sample volumes. With the use of an additional tracer, glucose rate of appearance can also be measured during the same analysis. Thus the new method makes measurements of gluconeogenesis available and affordable to large numbers of investigators under conditions of low and high fractional gluconeogenesis ( approximately 10 to approximately 90) in all subject populations.

Impact on the deuterium retention of simultaneous exposure of tungsten to a steady state plasma and transient heat cycling loads

NASA Astrophysics Data System (ADS)

Huber, A.; Sergienko, G.; Wirtz, M.; Steudel, I.; Arakcheev, A.; Brezinsek, S.; Burdakov, A.; Dittmar, T.; Esser, H. G.; Kreter, A.; Linke, J.; Linsmeier, Ch; Mertens, Ph; Möller, S.; Philipps, V.; Pintsuk, G.; Reinhart, M.; Schweer, B.; Shoshin, A.; Terra, A.; Unterberg, B.

2016-02-01

The impact on the deuterium retention of simultaneous exposure of tungsten to a steady-state plasma and transient cyclic heat loads has been studied in the linear PSI-2 facility with the main objective of qualifying tungsten (W) as plasma-facing material. The transient heat loads were applied by a high-energy laser, a Nd:YAG laser (λ = 1064 nm) with an energy per pulse of up to 32 J and a duration of 1 ms. A pronounced increase in the D retention by a factor of 13 has been observed during the simultaneous transient heat loads and plasma exposure. These data indicate that the hydrogen clustering is enhanced by the thermal shock exposures, as seen on the increased blister size due to mobilization and thermal production of defects during transients. In addition, the significant increase of the D retention during the simultaneous loads could be explained by an increased diffusion of D atoms into the W material due to strong temperature gradients during the laser pulse exposure and to an increased mobility of D atoms along the shock-induced cracks. Only 24% of the retained deuterium is located inside the near-surface layer (d<4 μm). Enhanced blister formation has been observed under combined loading conditions at power densities close to the threshold for damaging. Blisters are not mainly responsible for the pronounced increase of the D retention.

H{sub 2} Ortho-to-para Conversion on Grains: A Route to Fast Deuterium Fractionation in Dense Cloud Cores?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bovino, S.; Grassi, T.; Schleicher, D. R. G.

Deuterium fractionation, i.e., the enhancement of deuterated species with respect to non-deuterated ones, is considered to be a reliable chemical clock of star-forming regions. This process is strongly affected by the ortho-to-para H{sub 2} ratio. In this Letter we explore the effect of the ortho–para (o–p) H{sub 2} conversion on grains on the deuteration timescale in fully-depleted dense cores, including the most relevant uncertainties that affect this complex process. We show that (i) the o–p H{sub 2} conversion on grains is not strongly influenced by the uncertainties on the conversion time and the sticking coefficient, and (ii) that the processmore » is controlled by the temperature and the residence time of ortho-H{sub 2} on the surface, i.e., by the binding energy. We find that for binding energies between 330 and 550 K, depending on the temperature, the o–p H{sub 2} conversion on grains can shorten the deuterium fractionation timescale by orders of magnitude, opening a new route for explaining the large observed deuteration fraction D {sub frac} in dense molecular cloud cores. Our results suggest that the star formation timescale, when estimated through the timescale to reach the observed deuteration fractions, might be shorter than previously proposed. However, more accurate measurements of the binding energy are needed in order to better assess the overall role of this process.« less

Paramagnetic Attraction of Impurity-Helium Solids

NASA Technical Reports Server (NTRS)

Bernard, E. P.; Boltnev, R. E.; Khmelenko, V. V.; Lee, D. M.

2003-01-01

Impurity-helium solids are formed when a mixture of impurity and helium gases enters a volume of superfluid helium. Typical choices of impurity gas are hydrogen deuteride, deuterium, nitrogen, neon and argon, or a mixture of these. These solids consist of individual impurity atoms and molecules as well as clusters of impurity atoms and molecules covered with layers of solidified helium. The clusters have an imperfect crystalline structure and diameters ranging up to 90 angstroms, depending somewhat on the choice of impurity. Immediately following formation the clusters aggregate into loosely connected porous solids that are submerged in and completely permeated by the liquid helium. Im-He solids are extremely effective at stabilizing high concentrations of free radicals, which can be introduced by applying a high power RF dis- charge to the impurity gas mixture just before it strikes the super fluid helium. Average concentrations of 10(exp 19) nitrogen atoms/cc and 5 x 10(exp 18) deuterium atoms/cc can be achieved this way. It shows a typical sample formed from a mixture of atomic and molecular hydrogen and deuterium. It shows typical sample formed from atomic and molecular nitrogen. Much of the stability of Im-He solids is attributed to their very large surface area to volume ratio and their permeation by super fluid helium. Heat resulting from a chance meeting and recombination of free radicals is quickly dissipated by the super fluid helium instead of thermally promoting the diffusion of other nearby free radicals.

The impact of nano-coating on surface charge accumulation of epoxy resin insulator: characteristic and mechanism

NASA Astrophysics Data System (ADS)

Qi, Bo; Gao, Chunjia; Lv, Yuzhen; Li, Chengrong; Tu, Youping; Xiong, Jun

2018-06-01

The flashover phenomenon of the insulator is the main cause for insulating failure of GIS/GIL, and one of the most critical impacting factors is the accumulation of surface charge. The common methods to restrain the surface charge accumulation are reviewed in this paper. Through the reasonable comparison and analysis of these methods, nano-coatings for the insulator were selected as a way to restrain the surface charge accumulation. Based on this, six nano-coated epoxy resin samples with different concentrations of P25-TiO2 nanoparticles were produced. A high precision 3D surface charge measurement system was developed in this paper with a spatial resolution of 4.0 mm2 and a charge resolution of 0.01 µC (m2 · mV)‑1. The experimental results for the epoxy resin sample showed that with the concentration of nanoparticles of the coating material increasing, the surface charge density tended to first decrease and then increase. In the sample coated with 0.5% concentration of nanoparticles, the suppression effect is the optimum, leading to a 63.8% reduction of charge density under DC voltage. The application test for actual nano-coated GIS/GIL basin insulator indicated that the maximum suppression degree for the charge density under DC voltage could reach 48.3%, while it could reach 22.2% for switching impulse voltage and 12.5% for AC context. The control mechanism of nano-coatings on charge accumulation was proposed based on the analysis for surface morphology features and traps characteristics; the shallow traps dominate in the migration of charges while the deep traps operate on the charge accumulation. With the concentration of nanoparticles in nano-coating material mounting up, the density of shallow traps continuously increases, while for deep traps, it first decreases and then increases. For the sample with 0.5% concentration of nanoparticles coated, the competition between shallow traps and deep traps comes to the most balanced state, producing the most significant suppression impact on surface charge accumulation.

Vanadium hydride deuterium-tritium generator

DOEpatents

Christensen, L.D.

1980-03-13

A pressure controlled vanadium hydride gas generator was designed to provide deuterium-tritium gas in a series of pressure increments. A high pressure chamber filled with vanadium-deuterium-tritium hydride is surrounded by a heater which controls the hydride temperature. The heater is actuated by a power controller which responds to the difference signal between the actual pressure signal and a programmed pressure signal.

Temperature derivatives for fusion reactivity of D-D and D-T

DOE Office of Scientific and Technical Information (OSTI.GOV)

Langenbrunner, James R.; Makaruk, Hanna Ewa

Deuterium-tritium (D-T) and deuterium-deuterium (D-D) fusion reaction rates are observable using leakage gamma flux. A direct measurement of γ-rays with equipment that exhibits fast temporal response could be used to infer temperature, if the detector signal is amenable for taking the logarithmic time-derivative, alpha. We consider the temperature dependence for fusion cross section reactivity.

[Consideration of the deuterium-free water supply to an expedition to Mars].

PubMed

Siniak, Iu E; Turusov, V S; Grigor'ev, A I; Zaridze, D G; Gaĭdadymov, V B; Gus'kova, E I; Antoshina, E E; Gor'kova, T G; Trukhanova, L S

2003-01-01

Interplanetary missions, including to Mars, will put crews into severe radiation conditions. Search for methods of reducing the risk of radiation-induced cancer is of the top priority in preparation for the mission to Mars. One of the options is designing life support systems that will generate water with low content of the stable hydrogen isotope (deuterium) to be consumed by crewmembers. Preliminary investigations have shown that a decrease of the deuterium fraction by 65% does impart to water certain anti-cancer properties. Therefore, drinking deuterium-free water has the potential to reduce the risk of cancer consequent to the extreme radiation exposure of the Martian crew.

On the Possibility of Creating a Point-Like Neutron Source

NASA Astrophysics Data System (ADS)

Golubev, S. V.; Skalyga, V. A.; Izotov, I. V.; Sidorov, A. V.; Razin, S. V.; Shaposhnikov, R. A.; Lapin, R. L.; Bokhanov, A. F.; Kazakov, M. Yu.

2018-03-01

We consider the possibility of creating a compact high-power neutron generator with a small emitting area (of the order of 100 μm) and a neutron yield of 1010s-1 on the basis of a deuterium-deuterium fusion reaction (or 1012 s-1 on the basis of a deuterium-tritium fusion reaction). The fusion takes place under bombardment of a deuterium- (or tritium-) saturated target by a high-current (about 100 mA) focused deuterium ion beam with an energy of 100 keV. The ion beam with total current at a level of hundreds of milliamperes and small emittance (less than 0.1 π·mm·mrad), which is crucial for sharp focusing, can be generated by a quasi-gas-dynamic ion source of a new generation created on the basis of a discharge in an open magnetic trap sustained by high-power electromagnetic radiation of the millimeter wavelength range under electron cyclotron resonance conditions. Simulations of the focusing system for the experimentally obtained ion beam show the possibility to create a deuterium ion beam with a transverse size of 200 μm on the neutron-forming target. Prospects for using such a neutron source for neutron tomography are discussed.

Deuterium Enrichment of Amino and Hydroxy Acids Found in the Murchison Meteorite: Constraints on Parent Body Conditions

NASA Technical Reports Server (NTRS)

Lerner, Narcinda R.; Chang, Sherwood (Technical Monitor)

1997-01-01

The alpha-amino and alpha-hydroxy acids found in the Murchison carbonaceous chondrite are deuterium enriched. These compounds are thought to have originated from common deuterium enriched carbonyl precursors, by way of a Strecker synthesis which took place in a solution of HCN, NH3, and carbonyl compounds during the period of aqueous alteration of the meteorite parent body. However, the hydroxy acids found on Murchison are less deuterium enriched than the amino acids. With the objective of determining if the discrepancy in deuterium enrichment between the amino acids and the hydroxy acids found on Murchison is consistent with their formation in a Strecker synthesis, we have measured the deuterium content of alpha-amino and alpha-hydroxy acids produced in solutions of deuterated carbonyl compounds, KCN and NH4Cl, and also in mixtures of such solutions and Allende dust at 263 K and 295 K. Retention of the isotopic signature of the starting carbonyl by both alpha amino acids and alpha hydroxy acids is more dependent upon temperature, concentration and pH than upon the presence of meteorite dust in the solution. The constraints these observations place on Murchison parent body conditions will be discussed.

Effect of gas filling pressure and operation energy on ion and neutron emission in a medium energy plasma focus device

NASA Astrophysics Data System (ADS)

Niranjan, Ram; Rout, R. K.; Srivastava, Rohit; Kaushik, T. C.

2018-03-01

The effects of gas filling pressure and operation energy on deuterium ions and neutrons have been studied in a medium energy plasma focus device, MEPF-12. The deuterium gas filling pressure was varied from 1 to 10 mbar at an operation energy of 9.7 kJ. Also, the operation energy was varied from 3.9 to 9.7 kJ at a deuterium gas filling pressure of 4 mbar. Time resolved emission of deuterium ions was measured using a Faraday cup. Simultaneously, time integrated and time resolved emissions of neutrons were measured using a silver activation detector and plastic scintillator detector, respectively. Various characteristics (fluence, peak density, and most probable energy) of deuterium ions were estimated using the Faraday cup signal. The fluence was found to be nearly independent of the gas filling pressure and operation energy, but the peak density and most probable energy of deuterium ions were found to be varying. The neutron yield was observed to be varying with the gas filling pressure and operation energy. The effect of ions on neutrons emission was observed at each operation condition.

Comparison of the recently proposed super-Marx generator approach to thermonuclear ignition with the deuterium-tritium laser fusion-fission hybrid concept by the Lawrence Livermore National Laboratory

DOE PAGES

Winterberg, F.

2009-01-01

The recently proposed super-Marx generator pure deuterium microdetonation ignition concept is compared to the Lawrence Livermore National Ignition Facility (NIF) Laser deuterium-tritium fusion-fission hybrid concept (LIFE). In a super-Marx generator, a large number of ordinary Marx generators charge up a much larger second stage ultrahigh voltage Marx generator from which for the ignition of a pure deuterium microexplosion an intense GeV ion beam can be extracted. Typical examples of the LIFE concept are a fusion gain of 30 and a fission gain of 10, making up a total gain of 300, with about ten times more energy released into fissionmore » as compared to fusion. This means the substantial release of fission products, as in fissionless pure fission reactors. In the super-Marx approach for the ignition of pure deuterium microdetonation, a gain of the same magnitude can, in theory, be reached. If feasible, the super-Marx generator deuterium ignition approach would make lasers obsolete as a means for the ignition of thermonuclear microexplosions.« less

Source, movement and age of groundwater in the upper part of the Mojave River Basin, California, USA

USGS Publications Warehouse

Izbicki, J.A.; Martin, P.; Michel, R.L.

1995-01-01

Water samples from wells were collected and analysed for oxygen-18, deuterium, tritium, carbon-14, and carbon-13 to determine the source, movement and age of groundwater in the upper part of the Mojave River basin. Water in the alluvial aquifer has a median deuterium composition of -66??? and contains tritium, and was recently recharged by water from the Mojave River. Water in the regional aquifer near the Mojave River, near Summit Valley, and underlying several small washes has deuterium compositions heavier than -60???. Although some water in the regional aquifer near the Mojave River contains tritium, most of this water does not contain tritium. Carbon-14 data indicate that this water was recharged less than 2400 years ago. Water in the remainder of the regional aquifer has a median deuterium composition of -84???, which is as much as 20??? lighter than the volume-weighted deuterium composition of present-day precipitation. These data show that this water was recharged under climatic conditions different from average conditions today. Carbon-14 data indicate that some water in the regional aquifer was recharged more than 20 000 years ago.Water samples from wells were collected and analyzed for oxygen-18, deuterium, tritium, carbon-14, and carbon-13 to determine the source, movement and age of groundwater in the upper part of the Mojave River basin. Water in the alluvial aquifer has a median deuterium composition of -66qq and contains tritium, and was recently recharged by water from the Mojave River. Water in the regional aquifer near the Mojave River, near Summit Valley, and underlying several small washes has deuterium compositions heavier than -60qq. Although some water in the regional aquifer near the Mojave River contains tritium, most of this water does not contain tritium. Carbon-14 data indicate that this water was recharged less than 2400 years ago. Water in the remainder of the regional aquifer has a median deuterium composition of -84qq, which is as much as 20qq lighter than the volume-weighted deuterium composition of present-day precipitation. These data show that this water was recharged under climatic conditions different from average conditions today. Carbon-14 data indicate that some water in the regional aquifer was recharged more than 20 000 years ago.

Lagrangian process attribution of isotopic variations in near-surface water vapour in a 30-year regional climate simulation over Europe

NASA Astrophysics Data System (ADS)

Dütsch, Marina; Pfahl, Stephan; Meyer, Miro; Wernli, Heini

2018-02-01

Stable water isotopes are naturally available tracers of moisture in the atmosphere. Due to isotopic fractionation, they record information about condensation and evaporation processes during the transport of air parcels, and therefore present a valuable means for studying the global water cycle. However, the meteorological processes driving isotopic variations are complex and not very well understood so far, in particular on short (hourly to daily) timescales. This study presents a Lagrangian method for attributing the isotopic composition of air parcels to meteorological processes, which provides new insight into the isotopic history of air parcels. It is based on the temporal evolution of the isotope ratios, the humidity, the temperature, and the location of the air parcels. Here these values are extracted along 7-day backward trajectories started every 6 hours from near the surface in a 30-year regional climate simulation over Europe with the isotope-enabled version of the model of the Consortium for Small-Scale Modelling (COSMOiso). The COSMOiso simulation has a horizontal resolution of 0.25° and is driven at the lateral boundaries by a T106 global climate simulation with the isotope-enabled version of the European Centre Hamburg model (ECHAMwiso). Both simulations are validated against measurements from the Global Network of Isotopes in Precipitation (GNIP), which shows that nesting COSMOiso within ECHAMwiso improves the representation of δ2H and deuterium excess in monthly accumulated precipitation. The method considers all isotopic changes that occur inside the COSMOiso model domain, which, on average, correspond to more than half of the mean and variability in both δ2H and deuterium excess at the air parcels' arrival points. Along every trajectory, the variations in the isotope values are quantitatively decomposed into eight process categories (evaporation from the ocean, evapotranspiration from land, mixing with moister air, mixing with drier air, liquid cloud formation, mixed phase cloud formation, ice cloud formation, and no process). The results show that for air parcels arriving over the ocean, evaporation from the ocean is the primary factor controlling δ2H and deuterium excess. Over land, evapotranspiration from land and mixing with moister air are similarly important. Liquid and mixed phase cloud formation contribute to the variability of δ2H and deuterium excess, especially over continental Europe. In summary, the presented method helps to better understand the linkage between the meteorological history of air parcels and their isotopic composition, and may support the interpretation of stable water isotope measurements in future.

Condensed Matter Nuclear Science

NASA Astrophysics Data System (ADS)

Takahashi, Akito; Ota, Ken-Ichiro; Iwamura, Yashuhiro

Preface -- 1. General. Progress in condensed matter nuclear science / A. Takahashi. Summary of ICCF-12 / X. Z. Li. Overview of light water/hydrogen-based low-energy nuclear reactions / G. H. Miley and P. J. Shrestha -- 2. Excess heat and He detection. Development of "DS-reactor" as the practical reactor of "cold fusion" based on the "DS-cell" with "DS-cathode" / Y. Arata and Y.-C. Zhang. Progress in excess of power experiments with electrochemical loading of deuterium in palladium / V. Violante ... [et al.]. Anomalous energy generation during conventional electrolysis / T. Mizuno and Y. Toriyabe. "Excess heat" induced by deuterium flux in palladium film / B. Liu ... [et al.]. Abnormal excess heat observed during Mizuno-type experiments / J.-F. Fauvarque, P. P. Clauzon and G. J.-M. Lallevé. Seebeck envelope calorimetry with a Pd|D[symbol]O + H[symbol]SO[symbol] electrolytic cell / W.-S. Zhang, J. Dash and Q. Wang. Observation and investigation of nuclear fusion and self-induced electric discharges in liquids / A. I. Koldamasov ... [et al.]. Description of a sensitive seebeck calorimeter used for cold fusion studies / E. Storms. Some recent results at ENEA / M. Apicella ... [et al.]. Heat measurement during plasma electrolysis / K. Iizumi ... [et al.]. Effect of an additive on thermal output during electrolysis of heavy water with a palladium cathode / Q. Wang and J. Dash. Thermal analysis of calorimetric systems / L. D'Aulerio ... [et al.]. Surface plasmons and low-energy nuclear reactions triggering / E. Castagna ... [et al.]. Production method for violent TCB jet plasma from cavity / F. Amini. New results and an ongoing excess heat controversy / L. Kowalski ... [et al.] -- 3. Transmutation. Observation of surface distribution of products by X-ray fluorescence spectrometry during D[symbol] gas permeation through Pd Complexes / Y. Iwamura ... [et al.]. Discharge experiment using Pd/CaO/Pd multi-layered cathode / S. Narita ... [et al.]. Producing transmutation element on multi-layered Pd sample by deuterium permeation / H. Yamada ... [et al.]. Experimental observation and combined investigation of high-performance fusion of iron-region isotopes in optimal growing microbiological associations / V. I. Vysotskii ... [et al.]. Research into low-energy nuclear reactions in cathode sample solid with production of excess heat, stable and radioactive impurity nuclides / A. B. Karabut. Influence of parameters of the glow discharge on change of structure and the isotope composition of the cathode materials / I. B. Savvatimova and D. V. Gavritenkov. Elemental analysis of palladium electrodes after Pd/Pd light water critical electrolysis / Y. Toriyabe ... [et al.]. Progress on the study of isotopic composition in metallic thin films undergone to electrochemical loading of hydrogen / M. Apicella ... [et al.]. In situ accelerator analyses of palladium complex under deuterium permeation / A. Kitamura ... [et al.]. High-resolution mass spectrum for deuterium (hydrogen) gas permeating palladium film / Q. M. Wei ... [et al.]. ICP-MS analysis of electrodes and electrolytes after HNO[symbol]/H[symbol]O electrolysis / S. Taniguchi ... [et al.]. The Italy-Japan project - fundamental research on cold transmutation process for treatment of nuclear wastes / A. Takahashi, F. Celani and Y. Iwamura -- 4. Nuclear physics approach. Reproducible nuclear emissions from Pd/PdO:Dx heterostructure during controlled exothermic deuterium desorption / A. G. Lipson ... [et al.]. Correct identification of energetic alpha and proton tracks in experiments on CR-39 charged particle detection during hydrogen desorption from Pd/PdO:H[symbol] heterostructure / A. S. Roussetski ... [et al.]. Intense non-linear soft X-ray emission from a hydride target during pulsed D bombardment / G. H. Miley ... [et al.]. Enhancement of first wall damage in ITER type TOKAMAK due to LENR effects / A. G. Lipson, G. H. Miley and H. Momota. Generation of DD-reactions in a ferroelectric KD[symbol]PO[symbol] single crystal during transition through curie point (Tc = 220K) / A. G. Lipson ... [et al.]. Study of energetic and temporal characteristics of X-ray emission from solid-state cathode medium of high-current glow discharge / A. B. Karabut. A novel LiF-based detector for X-ray imaging in hydrogen loaded Ni films under laser irradiation / R. M. Montereali ... [et al.]. Observation and modeling of the ordered motion of hypothetical magnetically charged particles on the multilayer surface and the problem of low-energy fusion / S. V. Adamenko and V. I. Vysotskii -- 5. Material science. Evidence of superstoichiometric H/D lenr active sites and high-temperature superconductivity in a hydrogen-cycled Pd/PdO / A. G. Lipson ... [et al.]. New procedures to make active, fractal-like surfaces on thin Pd wires / F. Celani ... [et al.]. Using resistivity to measure H/Pd and D/Pd loading: Method and significance / M. C. H. McKubre and F. L. Tanzella. Measurements of the temperature coefficient of electric resistivity of hydrogen overloaded Pd / A. Spallone ... [et al.]. Magnetic interaction of hypothetical particles moving beneath the electrode/electrolyte interface to elucidate evolution mechanism of vortex appeared on Pd surface after long-term evolution of deuterium in 0.1 m LiOD / H. Numata and M. Ban. Unusual structures on the material surfaces irradiated by low-energy ions / B. Rodionov and I. Savvatimova -- 6. Theory. Context for understanding why particular nanoscale crystals turn-on faster and other LENR effects / S. R. Chubb. Models for anomalies in condensed matter deuterides / P. L. Hagelstein. Time-dependent EQPET analysis of TSC / A. Takahashi. Unifying theory of low-energy nuclear reaction and transmutation processes in deuterated/hydrogenated metals, acoustic cavitation, glow discharge, and deuteron beam experiments / Y. E. Kim and A. L. Zubarev. Catalytic fusion and the interface between insulators and transition metals / T. A. Chubb. Multiple scattering of deuterium wave function near surface of palladium lattice / X. Z. Li ... [et al.]. Theoretical comparison between semi-classical and quantum tunneling effect / F. Frisone. New cooperative mechanisms of low-energy nuclear reactions using super low-energy external field / F. A. Gareev and I. E. Zhidkova. Polyneutron theory of transmutation / J. C. Fisher. The thermal conduction from the centers of the nuclear reactions in solids / K.-I. Tsuchiya. Four-body RST general nuclear wavefunctions and matrix elements / I. Chaudhary and P. L. Hagelstein. Study on formation of tetrahedral or octahedral symmetric condensation by hopping of alkali or alkaline-earth metal ion / H. Miura. Calculations of nuclear reactions probability in a crystal lattice of lanthanum deuteride / V. A. Kirkinskii and Yu. A. Novikov. Possible coupled electron and electron neutrino in nucleus and its physical catalysis effect on D-D cold fusion into helium in Pd / M. Fukuhara. Tunnel resonance of electron wave and force of fluctuation / M. Ban. Types of nuclear fusion in solids / N. Yabuuchi. Neutrino-dineutron reactions (low-energy nuclear reactions induced by D[symbol] gas permeation through Pd complexes - Y. Iwamura effect) / V. Muromtsev, V. Platonov and I. Savvatimova. An explanation of earthquakes by the blacklight process and hydrogen fusion / H. Yamamoto. Theoretical modeling of electron flow action on probability of nuclear fusion of deuterons / A. I. Goncharov and V. A. Kirkinskii.

Ion Mobility Spectrometry-Hydrogen Deuterium Exchange Mass Spectrometry of Anions: Part 2. Assessing Charge Site Location and Isotope Scrambling

NASA Astrophysics Data System (ADS)

Khakinejad, Mahdiar; Ghassabi Kondalaji, Samaneh; Donohoe, Gregory C.; Valentine, Stephen J.

2016-03-01

Ion mobility spectrometry (IMS) coupled with gas-phase hydrogen deuterium exchange (HDX)-mass spectrometry (MS) and molecular dynamic simulations (MDS) has been used for structural investigation of anions produced by electrospraying a sample containing a synthetic peptide having the sequence KKDDDDDIIKIIK. In these experiments the potential of the analytical method for locating charge sites on ions as well as for utilizing collision-induced dissociation (CID) to reveal the degree of deuterium uptake within specific amino acid residues has been assessed. For diffuse (i.e., more elongated) [M - 2H]2- ions, decreased deuterium content along with MDS data suggest that the D4 and D6 residues are charge sites, whereas for the more diffuse [M - 3H]3- ions, the data suggest that the D4, D7, and the C-terminus are deprotonated. Fragmentation of mobility-selected, diffuse [M - 2H]2- ions to determine deuterium uptake at individual amino acid residues reveals a degree of deuterium retention at incorporation sites. Although the diffuse [M - 3H]3- ions may show more HD scrambling, it is not possible to clearly distinguish HD scrambling from the expected deuterium uptake based on a hydrogen accessibility model. The capability of the IMS-HDX-MS/MS approach to provide relevant details about ion structure is discussed. Additionally, the ability to extend the approach for locating protonation sites on positively-charged ions is presented.

Energy Levels of Hydrogen and Deuterium

National Institute of Standards and Technology Data Gateway

SRD 142 NIST Energy Levels of Hydrogen and Deuterium (Web, free access)   This database provides theoretical values of energy levels of hydrogen and deuterium for principle quantum numbers n = 1 to 200 and all allowed orbital angular momenta l and total angular momenta j. The values are based on current knowledge of the revelant theoretical contributions including relativistic, quantum electrodynamic, recoil, and nuclear size effects.

Can perchlorates be transformed to hydrogen peroxide (H2O2) products by cosmic rays on the Martian surface?

NASA Astrophysics Data System (ADS)

Crandall, Parker B.; Góbi, Sándor; Gillis-Davis, Jeffrey; Kaiser, Ralf I.

2017-09-01

Due to their oxidizing properties, perchlorates (ClO4-) are suggested by the planetary science community to play a vital role in the scarcity of organics on the Martian surface. However, alternative oxidation agents such as hydrogen peroxide (H2O2) have received surprisingly little attention. In this study, samples of magnesium perchlorate hexahydrate (Mg(ClO4)2 · 6H2O) were exposed to monoenergetic electrons and D2+ ions separately, sequentially, and simultaneously to probe the effects of galactic cosmic ray exposure of perchlorates and the potential incorporation of hydrogen (deuterium) into these minerals. The experiments were carried out under ultrahigh-vacuum conditions at 50 K, after which the samples were slowly heated to 300 K while the subliming products were monitored by a quadrupole mass spectrometer. In all cases, molecular oxygen (O2) was detected upon the onset of irradiation and also during the warmup phase. In case of a simultaneous D2+-electron exposure, deuterated water (D2O) and deuterium peroxide (D2O2) were also detected in the warmup phase, whereas only small amounts of D2O2 were found after an exclusive D2+ irradiation. These experiments yield the first data identifying hydrogen peroxide as a potential product in the interaction of cosmic rays with perchlorates in the Martian regolith revealing that perchlorates are capable of producing multiple oxidizing agents (O2 and D2O2) that may account for the destruction of organics on the Martian surface.

The permeation behavior of deuterium through 1Cr18Ni9Ti stainless steel with TiN+TiC-TiN multiple films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xiong, Y.; Song, J.; Luo, D.

The prevention of tritium losses via permeation through structure components is an important issue in fusion technology. The production of thin layers on materials with low diffusivity and/or low surface recombination constants (so-called permeation barriers) seems to be the most practical method to reduce or hinder the permeation of tritium through materials. TiN+TiC+TiN multiple films are deposited on the surface of 1Cr18Ni9Ti stainless steel by ion-beam assisted deposition technology. The characteristics of films are tested by XPS ASEM and XRD, which shows that the film are compact and uniform with a thickness of about 15 μm, and have a goodmore » adherence with the substrate below 773 K. The diffraction peaks in the XRD patterns for TiC and TiN are broadened, implying that the multiple films are deposited on the surface of 1Cr18Ni9Ti stainless steel. Meanwhile, the C-H bonded CH{sub 4}-appears in the infrared spectra of multiple films, suggesting that the CH{sub 4}- is in a static state, so hydrogen atom cannot migrate from the site bonded with carbon to a neighboring site. The measured deuterium permeability in 1Cr18Ni9Ti stainless steel coated with multiple films is 2-3 orders of magnitude lower than that of pure 1Cr18Ni9Ti stainless steel substrate from 473 K to 773 K. However, this barrier is partly destroyed above 773 K.« less

Deuterium Enrichment of PAHs by VUV Irradiation of Interstellar Ices

NASA Technical Reports Server (NTRS)

Bernstein, Max P.; Sandford, Scott A.; Allamandola, Louis J.; Gillette, J. Seb; Zare, Richard N.; DeVincenzi, Donald (Technical Monitor)

1998-01-01

Laboratory results demonstrate that polycyclic aromatic hydrocarbons (PAHs) rapidly exchange their hydrogen atoms with those of nearby molecules when they are frozen into low-temperature ices and exposed to vacuum ultraviolet radiation. As a result, PAHs quickly become deuterium-enriched when VUV irradiated in D-containing ices. This mechanism has important consequences for several astrophysical issues owing to the ubiquitous nature of PAHs in the interstellar medium. For example, this process may explain the deuterium enrichments found in PAHs in meteorites and interplanetary dust particles. These results also provide general predictions about the molecular siting of the deuterium on aromatic materials in meteorites if this process produced a significant fraction of their D-enrichment.

Thermally induced hydrosilylation at deuterium-terminated silicon nanoparticles: an investigation of the radical chain propagation mechanism.

PubMed

Holm, Jason; Roberts, Jeffrey T

2009-06-16

Isotopic labeling techniques were employed to study alkene addition to hydrogen- and deuterium-terminated silicon nanoparticles. Deuterium-terminated silicon nanoparticle synthesis is described, as is the characterization of fresh deuterium-terminated particles by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and in situ Fourier transform infrared spectroscopy (FTIR). Particles were refluxed in pure 1-dodecene and subsequently characterized by FTIR and nuclear magnetic resonance (NMR) spectroscopy. (1)H NMR results showed features consistent with dodecyl-terminated nanoparticles. Infrared absorption spectra of refluxed particles showed strong evidence of new C-D bond formation, which is consistent with a radical chain mechanism for alkene addition by hydrosilylation.

Negative-hydrogen-ion production from a nanoporous 12CaO • 7Al2O3 electride surface

NASA Astrophysics Data System (ADS)

Sasao, Mamiko; Moussaoui, Roba; Kogut, Dmitry; Ellis, James; Cartry, Gilles; Wada, Motoi; Tsumori, Katsuyoshi; Hosono, Hideo

2018-06-01

A high production rate of negative hydrogen ions (H‑) was observed from a nanoporous 12CaO • 7Al2O3 (C12A7) electride surface immersed in hydrogen/deuterium low-pressure plasmas. The target was negatively biased at 20–130 V, and the target surface was bombarded by H3 + ions from the plasma. The production rate was compared with that from a clean molybdenum surface. Using the pseudo-exponential work-function dependence of the H‑ production rate, the total H‑ yield from the C12A7 electride surface bombarded at 80 V was evaluated to be 25% of that from a cesiated molybdenum surface with the lowest work-function. The measured H‑ energy spectrum indicates that the major production mechanism is desorption by sputtering. This material has potential to be used as a production surface of cesium-free negative ion sources for accelerators, heating beams in nuclear fusion, and surface modification for industrial applications.

Concentration and removal of tritium and/or deuterium from water contaminated with tritium and/or deuterium

DOEpatents

Meyer, Thomas J.; Narula, Poonam M.

2001-01-01

Concentration of tritium and/or deuterium that is a contaminant in H.sub.2 O, followed by separation of the concentrate from the H.sub.2 O. Employed are certain metal oxo complexes, preferably with a metal from Group VIII. For instance, [Ru.sup.IV (2,2',6',2"-terpyridine)(2,2'-bipyridine)(O)](ClO.sub.4).sub.2 is very suitable.

Production of 14 MeV neutrons by heavy ions

DOEpatents

Brugger, Robert M.; Miller, Lowell G.; Young, Robert C.

1977-01-01

This invention relates to a neutron generator and a method for the production of 14 MeV neutrons. Heavy ions are accelerated to impinge upon a target mixture of deuterium and tritium to produce recoil atoms of deuterium and tritium. These recoil atoms have a sufficient energy such that they interact with other atoms of tritium or deuterium in the target mixture to produce approximately 14 MeV neutrons.

EFFECTS OF DEUTERIUM OXIDE UPON POLIOVIRUS MULTIPLICATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carp, R.I.; Kritchevsky, D.; Koprowski, H.

1960-09-01

The effects of deuterium oxide on the multiplication of CHAT, an attenuated type of poliomyeliths virus, was studied in cells of HeLa and of monkey kidney cells in primary cultures. Yields of virus obtained from deuterated cells were consistently higher than those obtained from controls. The incorporation of deuterium oxide in the growth media resulted in an increase in the average plague size of polio virus. (C.H.)

In-vivo NMR studies of deuterium-labeled photosensitizers in mice tumor model

NASA Astrophysics Data System (ADS)

Ramaprasad, Subbaraya; Liu, Y. H.; Pandey, R. K.; Shiau, Fuu-Yau; Smith, Kevin M.

1993-06-01

Photodynamic therapy (PDT) has emerged as a promising modality for the treatment of cancer. We are using newly synthesized and chemically defined and characterized porphyrin photosensitizers that are specifically labeled with deuterium to perform in vivo NMR studies in a murine tumor model. In vivo magnetic resonance offers the potential for repetitive, safe, noninvasive evaluation of photosensitizers, tumor metabolism, and the effect of PDT on the tumor metabolism. In an effort to monitor noninvasively the photosensitizers in an in vivo tumor model, we are synthesizing several deuterium labeled photosensitizers which absorb red light at or above 630 nm. Development of methods to test these photosensitizers directly in humans is not feasible at this time, since these photosensitizers are new and we do not yet understand the side effects. In addition, we do not understand the potential benefits compared with Photofrin II, the widely used photosensitizer. To perform our in vivo deuterium NMR studies on mouse foot tumors, we have constructed a solenoid coil which operates at 30.7 MHz for the deuterium nucleus. We have been able to detect the deuterium labeled photosensitizer in the tumor after a direct intra-tumor injection. The use of 31P NMR to predict the possible outcome of PDT in these tumors is also discussed.

High energy primary knock-on process in metal deuterium systems initiated by bombardment with noble gas ions

NASA Astrophysics Data System (ADS)

Gann, V. V.; Tolstolutskaya, G. D.

2008-08-01

An experimental study confirms the possibility of nuclear fusion reactions initiating in metal-deuterium targets by bombarding them with ions that are not the reagents of the fusion reaction, in particular, with noble gas ions. The yields of (d,d) and (d,t) reactions were measured as functions of energy (0.4-3.2 MeV) and mass of incident ions (He +, Ne +, Ar +, Kr + and Xe +). Irradiation by heavy ions produced a number of energetic deuterium atoms in the deuteride and deuterium + tritium metal targets. At ion energies of ˜0.1-1 MeV the d-d reaction yields are relatively high. A model of nuclear fusion reaction cross-sections in atomic collision cascades initiated by noble gas ion beam in metal-deuterium target is developed. The method for calculation tritium or deuterium recoil fluxes and the yield of d-d fusion reaction in subsequent collisions was proposed. It was shown that D(d,p)t and D(t,n) 4He reactions mainly occur in energy region of the recoiled D-atom from 10 keV to 250 keV. The calculated probabilities of d-d and d-t fusion reactions were found to be in a good agreement with the experimental data.

External reflection FTIR of peptide monolayer films in situ at the air/water interface: experimental design, spectra-structure correlations, and effects of hydrogen-deuterium exchange.

PubMed Central

Flach, C R; Brauner, J W; Taylor, J W; Baldwin, R C; Mendelsohn, R

1994-01-01

A Fourier transform infrared spectrometer has been interfaced with a surface balance and a new external reflection infrared sampling accessory, which permits the acquisition of spectra from protein monolayers in situ at the air/water interface. The accessory, a sample shuttle that permits the collection of spectra in alternating fashion from sample and background troughs, reduces interference from water vapor rotation-vibration bands in the amide I and amide II regions of protein spectra (1520-1690 cm-1) by nearly an order of magnitude. Residual interference from water vapor absorbance ranges from 50 to 200 microabsorbance units. The performance of the device is demonstrated through spectra of synthetic peptides designed to adopt alpha-helical, antiparallel beta-sheet, mixed beta-sheet/beta-turn, and unordered conformations at the air/water interface. The extent of exchange on the surface can be monitored from the relative intensities of the amide II and amide I modes. Hydrogen-deuterium exchange may lower the amide I frequency by as much as 11-12 cm-1 for helical secondary structures. This shifts the vibrational mode into a region normally associated with unordered structures and leads to uncertainties in the application of algorithms commonly used for determination of secondary structure from amide I contours of proteins in D2O solution. PMID:7919013

The production rate of cosmogenic deuterium at the Moon's surface

NASA Astrophysics Data System (ADS)

Füri, Evelyn; Deloule, Etienne; Trappitsch, Reto

2017-09-01

The hydrogen (D/H) isotope ratio is a key tracer for the source of planetary water. However, secondary processes such as solar wind implantation and cosmic ray induced spallation reactions have modified the primordial D/H signature of 'water' in all rocks and soils recovered on the Moon. Here, we re-evaluate the production rate of cosmogenic deuterium (D) at the Moon's surface through ion microprobe analyses of hydrogen isotopes in olivines from eight Apollo 12 and 15 mare basalts. These in situ measurements are complemented by CO2 laser extraction-static mass spectrometry analyses of cosmogenic noble gas nuclides (3He, 21Ne, 38Ar). Cosmic ray exposure (CRE) ages of the mare basalts, derived from their cosmogenic 21Ne content, range from 60 to 422 Ma. These CRE ages are 35% higher, on average, than the published values for the same samples. The amount of D detected in the olivines increases linearly with increasing CRE ages, consistent with a production rate of (2.17 ± 0.11) ×10-12 mol(g rock)-1 Ma-1. This value is more than twice as high as previous estimates for the production of D by galactic cosmic rays, indicating that for water-poor lunar samples, i.e., samples with water concentrations ≤50 ppm, corrected D/H ratios have been severely overestimated.

The production rate of cosmogenic deuterium at the Moon's surface

DOE PAGES

Füri, Evelyn; Deloule, Etienne; Trappitsch, Reto

2017-07-03

The hydrogen (D/H) isotope ratio is a key tracer for the source of planetary water. However, secondary processes such as solar wind implantation and cosmic ray induced spallation reactions have modified the primordial D/H signature of ‘water’ in all rocks and soils recovered on the Moon. We re-evaluate the production rate of cosmogenic deuterium (D) at the Moon's surface through ion microprobe analyses of hydrogen isotopes in olivines from eight Apollo 12 and 15 mare basalts. Furthermore, these in situ measurements are complemented by CO2 laser extraction-static mass spectrometry analyses of cosmogenic noble gas nuclides ( 3He, 21Ne, 38Ar). Cosmicmore » ray exposure (CRE) ages of the mare basalts, derived from their cosmogenic 21Ne content, range from 60 to 422 Ma. These CRE ages are 35% higher, on average, than the published values for the same samples. The amount of D detected in the olivines increases linearly with increasing CRE ages, consistent with a production rate of (2.17±0.11)×10 -12 mol(g rock) -1 Ma -1. This value is more than twice as high as previous estimates for the production of D by galactic cosmic rays, indicating that for water-poor lunar samples, i.e., samples with water concentrations ≤50 ppm, corrected D/H ratios have been severely overestimated.« less

Isotopic composition of waters from Ethiopia and Kenya: Insights into moisture sources for eastern Africa

NASA Astrophysics Data System (ADS)

Levin, Naomi E.; Zipser, Edward J.; Cerling, Thure E.

2009-12-01

Oxygen and deuterium isotopic values of meteoric waters from Ethiopia are unusually high when compared to waters from other high-elevation settings in Africa and worldwide. These high values are well documented; however, the climatic processes responsible for the isotopic anomalies in Ethiopian waters have not been thoroughly investigated. We use isotopic data from waters and remote data products to demonstrate how different moisture sources affect the distribution of stable isotopes in waters from eastern Africa. Oxygen and deuterium stable isotopic data from 349 surface and near-surface groundwaters indicate isotopic distinctions between waters in Ethiopia and Kenya and confirm the anomalous nature of Ethiopian waters. Remote data products from the Tropical Rainfall Measuring Mission (TRMM) and National Centers for Environmental Prediction (NCEP) reanalysis project show strong westerly and southwesterly components to low-level winds during precipitation events in western and central Ethiopia. This is in contrast to the easterly and southeasterly winds that bring rainfall to Kenya and southeastern Ethiopia. Large regions of high equivalent potential temperatures (θe) at low levels over the Sudd and the Congo Basin demonstrate the potential for these areas as sources of moisture and convective instability. The combination of wind direction data from Ethiopia and θe distribution in Africa indicates that transpired moisture from the Sudd and the Congo Basin is likely responsible for the high isotopic values of rainfall in Ethiopia.

Properties of thick GEM in low-pressure deuterium

NASA Astrophysics Data System (ADS)

Lee, C. S.; Ota, S.; Tokieda, H.; Kojima, R.; Watanabe, Y. N.; Uesaka, T.

2014-05-01

Deuteron inelastic scattering (d, d') provides a promising spectroscopic tool to study nuclear incompressibility. In studies of deuteron inelastic scattering of unstable nuclei, measurements of low-energy recoiled particles is very important. In order to perform these measurements, we are developing a GEM-TPC based gaseous active target, called CAT (Center for nuclear study Active Target), operated with pure deuterium gas. The CAT has been tested with deuterium gas at 1 atm and 100-μm-thick GEMs. The low-pressure operation of CAT is planned in order to improve the detection capability for lower-energy recoil particles. A 400 μm-thick gas electron multiplier (THGEM) was chosen for the low-pressure operation of CAT. However, the properties of THGEM in low-pressure deuterium are currently undocumented. In this work, the performance of THGEM with low-pressure pure deuterium gas has been investigated. The effective gas gain of THGEM has been measured in various conditions using a 5.5-MeV 241Am alpha source. The effective gas gain was measured for 0.2-, 0.3- and 0.4-atm deuterium gas and a gas gain of about 103 was achieved by a double THGEM structure at 0.2 atm. The maximum achieved gain decreased with increasing gas pressure. The dependences of the effective gas gain on the electric field strengths of the drift, transfer and induction regions were investigated. The gain stability as a function of time in hydrogen gas was also tested and a relaxation time of THGEM of about 60 hours was observed with a continuous irradiation of alpha particles, which is significantly longer than previous studies have reported. We have tried to evaluate the gas gain of THGEM in deuterium gas by considering only the Townsend ionization process; however, it turned out that more phenomenological aspects, such as transfer efficiency, should be included in the evaluation. The basic properties of THGEM in low-pressure deuterium have been investigated for the first time.

Long-term erosion of plasma-facing materials with different surface roughness in ASDEX Upgrade

NASA Astrophysics Data System (ADS)

Hakola, A.; Karhunen, J.; Koivuranta, S.; Likonen, J.; Balden, M.; Herrmann, A.; Mayer, M.; Müller, H. W.; Neu, R.; Rohde, V.; Sugiyama, K.; The ASDEX Upgrade Team

2014-04-01

The effect of surface roughness on the long-term erosion patterns of tungsten coatings was investigated in the outer strike-point region of ASDEX Upgrade during its 2010-11 plasma operations. The net erosion rates of rough coatings (Ra = 5-6 μm) were three to seven times smaller than those of smooth coatings (Ra = 0.4-0.8 μm). This is because rough surfaces are largely modified and damaged in the microscopic scale but the material is re-deposited together with boron, deuterium and carbon on the shadowed sides of the most prominent surface features. In addition, we observed that W coatings were eroded on average at a rate of 0.03 nm s-1, which was three to four times smaller than the value for Cr, simulating here steel.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clausing, R.E.

Results are summarized for an investigation of the sorption rates of gases on vapor-deposited titanium films. The usefulness of such films for ultrahigh speed vacuum pumping is appraised. The sorption of hydrogen, deuterium, oxygen, nitrogen, carbon monoxide, carbon dioxide, water vapor, helium, argon, and methane onto titanium films was measured for a variety of circumstances using techniques and apparatus developed for this specific purpose. The information obtained and techniques evolved in this study have shown that large-scale getter pumping is feasible and can be a very effective means of pumping many gases. Sticking fractions larger than 0.8 were obtained formore » hydrogen, deuterium, oxygen, nitrogen, carbon monoxide, and carbon dioxide. The experiments have shown that the sticking fraction for gases on vapor-deposited films is a function of the deposition conditions. There is strong evidence to support the supposition that conditions which favor the formation of a porous, fine-grained film structure with a large surface-to-volume ratio produce films with the highest sorption rates. The technique for measuring sticking fractions is new and in many respects unique. It utilizes a very large sorption surface, thus minimizing the perturbing effect of the instrumentation and evaporation apparatus and reducing the hazard of film contamination due to small leaks in the system or outgassing of system components. The method gives especially good accuracy for measurements of sticking fractions approaching unity. The quantity of gas adsorbed, the gas flux onto the getter surface, and the gas flux leaving the getter surface are measured directly. Any two of these three independent measurements can be used to determine the sticking fraction, thereby providing a means of checking the data. The evaporation techniques, substrate surface, and substrate area were chosen to very nearly duplicate the conditions likely to be encountered in the practical application of large-scale getter pumping. (auth)« less

The Effect of Ion Energy and Substrate Temperature on Deuterium Trapping in Tungsten

NASA Astrophysics Data System (ADS)

Roszell, John Patrick Town

Tungsten is a candidate plasma facing material for next generation magnetic fusion devices such as ITER and there are major operational and safety issues associated with hydrogen (tritium) retention in plasma facing components. An ion gun was used to simulate plasma-material interactions under various conditions in order to study hydrogen retention characteristics of tungsten thus enabling better predictions of hydrogen retention in ITER. Thermal Desorption Spectroscopy (TDS) was used to measure deuterium retention from ion irradiation while modelling of TDS spectra with the Tritium Migration Analysis Program (TMAP) was used to provide information about the trapping mechanisms involved in deuterium retention in tungsten. X-ray Photoelectron Spectroscopy (XPS) and Secondary Ion Mass Spectrometry (SIMS) were used to determine the depth resolved composition of specimens used for irradiation experiments. Carbon and oxygen atoms will be among the most common contaminants within ITER. C and O contamination in polycrystalline tungsten (PCW) specimens even at low levels (˜0.1%) was shown to reduce deuterium retention by preventing diffusion of deuterium into the bulk of the specimen. This diffusion barrier was also responsible for the inhibition of blister formation during irradiations at 500 K. These observations may provide possible mitigation techniques for problems associated with tritium retention and mechanical damage to plasma facing components caused by hydrogen implantation. Deuterium trapping in PCW and single crystal tungsten (SCW) was studied as a function of ion energy and substrate temperature. Deuterium retention was shown to decrease with decreasing ion energy below 100 eV/D+. Irradiation of tungsten specimens with 10 eV/D+ ions was shown to retain up to an order of magnitude less deuterium than irradiation with 500 eV/D+ ions. Furthermore, the retention mechanism for deuterium was shown to be consistent across the entire energy range studied (10-500 eV) with the shallow penetration depth of low energy ions being the major factor in the reduction in retention. A change in retention mechanism was observed as tungsten temperature during irradiation was increased from 300 to 500 K. Modelling of deuterium retention in 300 and 500 K SCW specimens revealed that two traps, 1.0 and 1.3 eV, are involved in retention for irradiations performed at 300K while a single 2.1 eV trap is present for 500 K irradiations. Experiments suggest that the 2.1 eV trap is created during irradiation of tungsten at 500 K and this process also involves the annihilation of the 1.3 and 1.0 eV traps.

Pulse power switch development

NASA Astrophysics Data System (ADS)

Harvey, R.; Gallagher, H.; Hansen, S.

1980-01-01

The objective of this study program has been to define an optimum technical approach to the longer range goal of achieving practical high repetition rate high power spark gap switches. Requirements and possible means of extending the state of the art of crossed field closing switches, vacuum spark gaps, and pressurized spark gaps are presented with emphasis on reliable, efficient and compact devices operable in burst mode at 250-300 kV, 40-60 kA, =1 kHz with approximately 50 nsec pulses rising in approximately 3 ns. Models of these devices are discussed which are based upon published and generated design data and on underlying physical principles. Based upon its relative advantages, limitations and tradeoffs we conclude that the Hughes Crossatron switch is the nearest term approach to reach the switch goal levels. Theoretical, experimental, and computer simulation models of the plasma show a collective ion acceleration mechanism to be active which is predicted to result in current rise times approaching 10 nsec. A preliminary design concept is presented. For faster rise times we have shown a vacuum surface flashover switch to be an interesting candidate. This device is limited by trigger instabilities and will require further basic development. The problem areas relevant to high pressure spark gaps are reviewed.

Enolate Stabilization by Anion-π Interactions: Deuterium Exchange in Malonate Dilactones on π-Acidic Surfaces.

PubMed

Miros, François N; Zhao, Yingjie; Sargsyan, Gevorg; Pupier, Marion; Besnard, Céline; Beuchat, César; Mareda, Jiri; Sakai, Naomi; Matile, Stefan

2016-02-18

Of central importance in chemistry and biology, enolate chemistry is an attractive topic to elaborate on possible contributions of anion-π interactions to catalysis. To demonstrate the existence of such contributions, experimental evidence for the stabilization of not only anions but also anionic intermediates and transition states on π-acidic aromatic surfaces is decisive. To tackle this challenge for enolate chemistry with maximal precision and minimal uncertainty, malonate dilactones are covalently positioned on the π-acidic surface of naphthalenediimides (NDIs). Their presence is directly visible in the upfield shifts of the α-protons in the (1) H NMR spectra. The reactivity of these protons on π-acidic surfaces is measured by hydrogen-deuterium (H-D) exchange for 11 different examples, excluding controls. The velocity of H-D exchange increases with π acidity (NDI core substituents: SO2 R>SOR>H>OR>OR/NR2 >SR>NR2 ). The H-D exchange kinetics vary with the structure of the enolate (malonates>methylmalonates, dilactones>dithiolactones). Moreover, they depend on the distance to the π surface (bridge length: 11-13 atoms). Most importantly, H-D exchange depends strongly on the chirality of the π surface (chiral sulfoxides as core substituents; the crystal structure of the enantiopure (R,R,P)-macrocycle is reported). For maximal π acidity, transition-state stabilizations up to -18.8 kJ mol(-1) are obtained for H-D exchange. The Brønsted acidity of the enols increases strongly with π acidity of the aromatic surface, the lowest measured pKa =10.9 calculates to a ΔpKa =-5.5. Corresponding to the deprotonation of arginine residues in neutral water, considered as "impossible" in biology, the found enolate-π interactions are very important. The strong dependence of enolate stabilization on the unprecedented seven-component π-acidity gradient over almost 1 eV demonstrates quantitatively that such important anion-π activities can be expected only from strong enough π acids. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Deuterium permeation of amorphous alumina coating on 316L prepared by MOCVD

NASA Astrophysics Data System (ADS)

Li, Shuai; He, Di; Liu, Xiaopeng; Wang, Shumao; Jiang, Lijun

2012-01-01

The deuterium permeation behavior of the alumina coating on 316L stainless steel prepared by metal organic chemical vapor deposition (MOCVD) was investigated. The alumina coating was also characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and scanning electron microscope (SEM). It was found that the as-prepared coating consisted of amorphous alumina. This alumina coating had a dense, crack-free and homogeneous morphology. Although the alumina coating was amorphous, effective suppression of deuterium permeation was demonstrated. The deuterium permeability of the alumina coating was 51-60 times less than that of the 316L stainless steel and 153-335 times less than that of the referred low activation martensitic steels at 860-960 K.

Channeling effect in polycrystalline deuterium-saturated CVD diamond target bombarded by deuterium ion beam

NASA Astrophysics Data System (ADS)

Bagulya, A. V.; Dalkarov, O. D.; Negodaev, M. A.; Rusetskii, A. S.; Chubenko, A. P.; Ralchenko, V. G.; Bolshakov, A. P.

2015-07-01

At the ion accelerator HELIS at LPI, the neutron yield is investigated in DD reactions within a strongly textured polycrystalline deuterium-saturated CVD diamond under irradiation by a deuterium ion beam with the energy of less than 30 keV. The measurements of the neutron flux in the beam direction are performed using a multichannel detector based on 3He counters, in dependence on the target angle, β, with respect to the beam axis. A significant anisotropy in the neutron yield is observed. At β = 0° the yield is higher by a factor of 3 as compared to that at β = ±45°. The possible reasons for the anisotropy, including ion channeling, are discussed.

THE EXCHANGE OF DEUTERIUM WITH METHANOL OVER RANEY NICKEL CATALYST AND THE EFFECT OF CERTAIN NITRO COMPOUNDS UPON THE EXCHANGE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, H.A.; Stewart, B.B.

Deuterium gas exchanges slowly with liquid methanol over Raney nickel catalyst at 35 deg . The reaction is zero order with respect to deuterium pressure and has a low activation energy. The influences of catalyst weight, catalyst treatment, and of the presence of certain nitro compounds were studied. Since active Raney nickel can liberate hydrogen directly, a method for determining the origin of hydrogen which undergoes exchange with the deuterium gas was developed. It was shown that the exchanged hydrogen does originate from the hydroxyl hydrogen of methanol. The results are discussed in the light of the mechanism of catalyticmore » exchange and catalytic hydrogenation reactions. (auth)« less

Study the Formation of H2, HD and D2 under Various Interstellar Conditions

NASA Astrophysics Data System (ADS)

Sahu, Dipen; Chakrabarti, Sandip Kumar; Das, Ankan

2016-07-01

Hydrogen is the most abundant molecule in the Interstellar medium (ISM). Formation of gas phase hydrogen molecule is inefficient; perhaps grain surface acts as a necessary ingredients for the formation of H_2 molecule. H atoms accrete on the grain surface, recombine there and desorb in the gas phase. Similarly, deuterium accretion on grain surfaces can produce simple dueterated molecules (HD and D_2) on the ISM. Unlike gas phase reactions, rate equations can not yield accurate result for grain surface reactions due to inherent randomness of surface species. We use Monte-Carlo method to follow this surface chemistry which effectively take care of this randomness. We use square grids and impose periodic boundary condition on them to mimic the spherical nature of grains. Various types of rough surfaces are considered to study the impact on effective production rates. We found that these simple but most important molecules are produced in low temperature (physisorption sites) as well as in high temperature (chemisorption sites) regions.

Photoionization of N,N,N[prime],N[prime]-tetramethylbenzidine in a mixed micelle of ionic and nonionic surfactants: Electron spin-echo modulation and electron spin resonance studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baglioni, P.; Rivara-Minten, E.; Stenland, C.

1991-11-28

Electron spin-echo modulation (ESEM) and electron spin resonance (ESR) spectra of the photogenerated N,N,N[prime],N[prime]-tetramethylbenzidine (TMB) cation radical in frozen mixed micelles of sodium dodecyl sulfate (SDS) or dodecyltrimethylammonium chloride (DTAC) and hexakis(ethylene glycol) monododecyl ether (C[sub 12]E[sub 6]), selectively deuterated along the poly(ethylene glycol) group (C[sub 12]D[sub 6]) or along the alkyl chain ((CD)[sub 12]E[sub 6]), have been studied as a function of the mixed-micelle composition in H[sub 2]O and D[sub 2]O. ESEM effects due to TMB[sup +] interactions with deuterium in D[sub 2]O show a decrease of the TMB[sup +]-water interactions for the system DTAC/C[sub 12]E[sub 6] and anmore » increase for the system SDS/C[sub 12]E[sub 6] that depend on the composition of the mixed micelle. The location of TMB[sup +] in the mixed micelles, deduced by comparing the modulation effects due to interactions of the photocation with water deuteriums or deuteriums of deuterated surfactants, is reported for the SDS/C[sub 12]E[sub 6] and DTAC/C[sub 12]E[sub 6] mixed micelles. The efficiency of charge separation upon the photoionization of TMB to produce TMB[sup +] measured by ESR correlates with the surface charge and with the degree of water penetration into the mixed micelle.« less

Cryogenic target formation using cold gas jets

DOEpatents

Hendricks, Charles D.

1981-01-01

A method and apparatus using cold gas jets for producing a substantially uniform layer of cryogenic materials on the inner surface of hollow spherical members having one or more layers, such as inertially imploded targets. By vaporizing and quickly refreezing cryogenic materials contained within a hollow spherical member, a uniform layer of the materials is formed on an inner surface of the spherical member. Basically the method involves directing cold gas jets onto a spherical member having one or more layers or shells and containing the cryogenic material, such as a deuterium-tritium (DT) mixture, to freeze the contained material, momentarily heating the spherical member so as to vaporize the contained material, and quickly refreezing the thus vaporized material forming a uniform layer of cryogenic material on an inner surface of the spherical member.

Cryogenic target formation using cold gas jets

DOEpatents

Hendricks, Charles D. [Livermore, CA

1980-02-26

A method and apparatus using cold gas jets for producing a substantially uniform layer of cryogenic materials on the inner surface of hollow spherical members having one or more layers, such as inertially imploded targets. By vaporizing and quickly refreezing cryogenic materials contained within a hollow spherical member, a uniform layer of the materials is formed on an inner surface of the spherical member. Basically the method involves directing cold gas jets onto a spherical member having one or more layers or shells and containing the cryogenic material, such as a deuterium-tritium (DT) mixture, to freeze the contained material, momentarily heating the spherical member so as to vaporize the contained material, and quickly refreezing the thus vaporized material forming a uniform layer of cryogenic material on an inner surface of the spherical member.

Plasma-surface interaction in negative hydrogen ion sources

NASA Astrophysics Data System (ADS)

Wada, Motoi

2018-05-01

A negative hydrogen ion source delivers more beam current when Cs is introduced to the discharge, but a continuous operation of the source reduces the beam current until more Cs is added to the source. This behavior can be explained by adsorption and ion induced desorption of Cs atoms on the plasma grid surface of the ion source. The interaction between the ion source plasma and the plasma grid surface of a negative hydrogen ion source is discussed in correlation to the Cs consumption of the ion source. The results show that operation with deuterium instead of hydrogen should require more Cs consumption and the presence of medium mass impurities as well as ions of the source wall materials in the arc discharge enlarges the Cs removal rate during an ion source discharge.

Determination of Backbone Amide Hydrogen Exchange Rates of Cytochrome c Using Partially Scrambled Electron Transfer Dissociation Data

NASA Astrophysics Data System (ADS)

Hamuro, Yoshitomo; E, Sook Yen

2018-05-01

The technological goal of hydrogen/deuterium exchange-mass spectrometry (HDX-MS) is to determine backbone amide hydrogen exchange rates. The most critical challenge to achieve this goal is obtaining the deuterium incorporation in single-amide resolution, and gas-phase fragmentation may provide a universal solution. The gas-phase fragmentation may generate the daughter ions which differ by a single amino acid and the difference in deuterium incorporations in the two analogous ions can yield the deuterium incorporation at the sub-localized site. Following the pioneering works by Jørgensen and Rand, several papers utilized the electron transfer dissociation (ETD) to determine the location of deuterium in single-amide resolution. This paper demonstrates further advancement of the strategy by determining backbone amide hydrogen exchange rates, instead of just determining deuterium incorporation at a single time point, in combination with a wide time window monitoring. A method to evaluate the effects of scrambling and to determine the exchange rates from partially scrambled HDX-ETD-MS data is described. All parent ions for ETD fragmentation were regio-selectively scrambled: The deuterium in some regions of a peptide ion was scrambled while that in the other regions was not scrambled. The method determined 31 backbone amide hydrogen exchange rates of cytochrome c in the non-scrambled regions. Good fragmentation of a parent ion, a low degree of scrambling, and a low number of exchangeable hydrogens in the preceding side chain are the important factors to determine the exchange rate. The exchange rates determined by the HDX-MS are in good agreement with those determined by NMR. [Figure not available: see fulltext.

Determination of Backbone Amide Hydrogen Exchange Rates of Cytochrome c Using Partially Scrambled Electron Transfer Dissociation Data.

PubMed

Hamuro, Yoshitomo; E, Sook Yen

2018-05-01

The technological goal of hydrogen/deuterium exchange-mass spectrometry (HDX-MS) is to determine backbone amide hydrogen exchange rates. The most critical challenge to achieve this goal is obtaining the deuterium incorporation in single-amide resolution, and gas-phase fragmentation may provide a universal solution. The gas-phase fragmentation may generate the daughter ions which differ by a single amino acid and the difference in deuterium incorporations in the two analogous ions can yield the deuterium incorporation at the sub-localized site. Following the pioneering works by Jørgensen and Rand, several papers utilized the electron transfer dissociation (ETD) to determine the location of deuterium in single-amide resolution. This paper demonstrates further advancement of the strategy by determining backbone amide hydrogen exchange rates, instead of just determining deuterium incorporation at a single time point, in combination with a wide time window monitoring. A method to evaluate the effects of scrambling and to determine the exchange rates from partially scrambled HDX-ETD-MS data is described. All parent ions for ETD fragmentation were regio-selectively scrambled: The deuterium in some regions of a peptide ion was scrambled while that in the other regions was not scrambled. The method determined 31 backbone amide hydrogen exchange rates of cytochrome c in the non-scrambled regions. Good fragmentation of a parent ion, a low degree of scrambling, and a low number of exchangeable hydrogens in the preceding side chain are the important factors to determine the exchange rate. The exchange rates determined by the HDX-MS are in good agreement with those determined by NMR. Graphical Abstract ᅟ.

Determination of Backbone Amide Hydrogen Exchange Rates of Cytochrome c Using Partially Scrambled Electron Transfer Dissociation Data

NASA Astrophysics Data System (ADS)

Hamuro, Yoshitomo; E, Sook Yen

2018-03-01

The technological goal of hydrogen/deuterium exchange-mass spectrometry (HDX-MS) is to determine backbone amide hydrogen exchange rates. The most critical challenge to achieve this goal is obtaining the deuterium incorporation in single-amide resolution, and gas-phase fragmentation may provide a universal solution. The gas-phase fragmentation may generate the daughter ions which differ by a single amino acid and the difference in deuterium incorporations in the two analogous ions can yield the deuterium incorporation at the sub-localized site. Following the pioneering works by Jørgensen and Rand, several papers utilized the electron transfer dissociation (ETD) to determine the location of deuterium in single-amide resolution. This paper demonstrates further advancement of the strategy by determining backbone amide hydrogen exchange rates, instead of just determining deuterium incorporation at a single time point, in combination with a wide time window monitoring. A method to evaluate the effects of scrambling and to determine the exchange rates from partially scrambled HDX-ETD-MS data is described. All parent ions for ETD fragmentation were regio-selectively scrambled: The deuterium in some regions of a peptide ion was scrambled while that in the other regions was not scrambled. The method determined 31 backbone amide hydrogen exchange rates of cytochrome c in the non-scrambled regions. Good fragmentation of a parent ion, a low degree of scrambling, and a low number of exchangeable hydrogens in the preceding side chain are the important factors to determine the exchange rate. The exchange rates determined by the HDX-MS are in good agreement with those determined by NMR. [Figure not available: see fulltext.

Hot ion plasma production in HIP-1 using water-cooled hollow cathodes

NASA Technical Reports Server (NTRS)

Reinmann, J. J.; Lauver, M. R.; Patch, R. W.; Layman, R. W.; Snyder, A.

1975-01-01

A steady-state ExB plasma was formed by applying a strong radially inward dc electric field near the mirror throats. Most of the results were for hydrogen, but deuterium and helium plasmas were also studied. Three water-cooled hollow cathodes were operated in the hot-ion plasma mode with the following results: (1) thermally emitting cathodes were not required to achieve the hot-ion mode; (2) steady-state operation (several minutes) was attained; (3) input powers greater than 40 kW were achieved; (4) cathode outside diameters were increased from 1.2 cm (uncooled) to 4.4 cm (water-cooled); (5) steady-state hydrogen plasma with ion temperatures from 185 to 770 eV and electron temperatures from 5 to 21 eV were produced. Scaling relations were empirically obtained for discharge current, ion temperature, electron temperature, and relative ion density as a function of hydrogen gas feed rate, magnetic field, and cathode voltage. Neutrons were produced from deuterium plasma, but it was not established whether thay came from the plasma volume or from the electrode surfaces.

Photoionization of N,N,N',N'-tetramethylbenzidine in anionic-cationic mixed micelles of sodium dodecyl sulfate-dodecyltrimethylammonium chloride: electron spin resonance and electron spin echo modulation studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rivara-Minten, E.; Baglioni, P.; Kevan, L.

1988-05-05

Electron spin echo modulation (ESEM) and electron spin resonance (ESR) spectra of the photogenerated N,N,N',N'-tetramethylbenzidine cation radical (TMB/sup +/) in frozen mixed micelles of dodecyltrimethylammonium chloride (DTAC) and sodium dodecyl sulfate (SDS) have been studied as a function of the mixed micelle composition. ESEM effects due to TMB/sup +/ interactions with deuterium in D/sub 2/O show a decrease of the TMB/sup +/-water interaction that depends on the SDS-DTAC mixed micelle composition and reaches a minimum for the equimolar mixed micelle. The efficiency of charge separation upon photoionization of TMB to produce TMB/sup +/ measured by ESR correlates with the degreemore » of water penetration into the micelle. ESEM effects due to interaction of x-doxylstearic acid nitroxide probes with deuterium in D/sub 2/O show that the decrease of water penetration is due to higher surface packing due to electrostatic attraction among the polar headgroups of the two surfactants.« less

Effect of neutron energy and fluence on deuterium retention behaviour in neutron irradiated tungsten

NASA Astrophysics Data System (ADS)

Fujita, Hiroe; Yuyama, Kenta; Li, Xiaochun; Hatano, Yuji; Toyama, Takeshi; Ohta, Masayuki; Ochiai, Kentaro; Yoshida, Naoaki; Chikada, Takumi; Oya, Yasuhisa

2016-02-01

Deuterium (D) retention behaviours for 14 MeV neutron irradiated tungsten (W) and fission neutron irradiated W were evaluated by thermal desorption spectroscopy (TDS) to elucidate the correlation between D retention and defect formation by different energy distributions of neutrons in W at the initial stage of fusion reactor operation. These results were compared with that for Fe2+ irradiated W with various damage concentrations. Although dense vacancies and voids within the shallow region near the surface were introduced by Fe2+ irradiation, single vacancies with low concentration were distributed throughout the sample for 14 MeV neutron irradiated W. Only the dislocation loops were introduced by fission neutron irradiation at low neutron fluence. The desorption peak of D for fission neutron irradiated W was concentrated at low temperature region less than 550 K, but that for 14 MeV neutron irradiated W was extended toward the higher temperature side due to D trapping by vacancies. It can be said that the neutron energy distribution could have a large impact on irradiation defect formation and the D retention behaviour.

Allosteric Coupling of CARMIL and V-1 Binding to Capping Protein Revealed by Hydrogen-Deuterium Exchange.

PubMed

Johnson, Britney; McConnell, Patrick; Kozlov, Alex G; Mekel, Marlene; Lohman, Timothy M; Gross, Michael L; Amarasinghe, Gaya K; Cooper, John A

2018-05-29

Actin assembly is important for cell motility. The ability of actin subunits to join or leave filaments via the barbed end is critical to actin dynamics. Capping protein (CP) binds to barbed ends to prevent subunit gain and loss and is regulated by proteins that include V-1 and CARMIL. V-1 inhibits CP by sterically blocking one binding site for actin. CARMILs bind at a distal site and decrease the affinity of CP for actin, suggested to be caused by conformational changes. We used hydrogen-deuterium exchange with mass spectrometry (HDX-MS) to probe changes in structural dynamics induced by V-1 and CARMIL binding to CP. V-1 and CARMIL induce changes in both proteins' binding sites on the surface of CP, along with a set of internal residues. Both also affect the conformation of CP's ββ subunit "tentacle," a second distal actin-binding site. Concerted regulation of actin assembly by CP occurs through allosteric couplings between CP modulator and actin binding sites. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.

Computational Simulation of High Energy Density Plasmas

DTIC Science & Technology

2009-10-30

the imploding liner. The PFS depends on a lithium barrier foil slowing the advance of deuterium up the coaxial gun to the corner. There the plasma ...the coaxial gun section, and Figure 4 shows the physical state of the plasma just prior to pinch. Figure 5 shows neutron yield reaching 1014 in this...details the channel geometry between the center cylinder and coaxial gas gun . The deuterium injection starts when the pressure of the deuterium gas in

Damage evaluation of proton irradiated titanium deuteride thin films to be used as neutron production targets

NASA Astrophysics Data System (ADS)

Suarez Anzorena, Manuel; Bertolo, Alma A.; Gagetti, Leonardo; Gaviola, Pedro A.; del Grosso, Mariela F.; Kreiner, Andrés J.

2018-06-01

Titanium deuteride thin films have been manufactured under different conditions specified by deuterium gas pressure, substrate temperature and time. The films were characterized by different techniques to evaluate the deuterium content and the homogeneity of such films. Samples with different concentrations of deuterium, including non deuterated samples, were irradiated with a 150 keV proton beam. Both deposits, pristine and irradiated, were characterized by optical profilometry and scanning electron microscopy.

Creatine Supplementation Increases Total Body Water in Soccer Players: a Deuterium Oxide Dilution Study.

PubMed

Deminice, R; Rosa, F T; Pfrimer, K; Ferrioli, E; Jordao, A A; Freitas, E

2016-02-01

This study aimed to evaluate changes in total body water (TBW) in soccer athletes using a deuterium oxide dilution method and bioelectrical impedance (BIA) formulas after 7 days of creatine supplementation. In a double-blind controlled manner, 13 healthy (under-20) soccer players were divided randomly in 2 supplementation groups: Placebo (Pla, n=6) and creatine supplementation (CR, n=7). Before and after the supplementation period (0.3 g/kg/d during 7 days), TBW was determined by deuterium oxide dilution and BIA methods. 7 days of creatine supplementation lead to a large increase in TBW (2.3±1.0 L) determined by deuterium oxide dilution, and a small but significant increase in total body weight (1.0±0.4 kg) in Cr group compared to Pla. The Pla group did not experience any significant changes in TBW or body weight. Although 5 of 6 BIA equations were sensitive to determine TBW changes induced by creatine supplementation, the Kushner et al. 16 method presented the best concordance levels when compared to deuterium dilution method. In conclusion, 7-days of creatine supplementation increased TBW determined by deuterium oxide dilution or BIA formulas. BIA can be useful to determine TBW changes promoted by creatine supplementation in soccer athletes, with special concern for formula choice. © Georg Thieme Verlag KG Stuttgart · New York.

The Variability of Atmospheric Deuterium Brightness at Mars: Evidence for Seasonal Dependence

NASA Astrophysics Data System (ADS)

Mayyasi, Majd; Clarke, John; Bhattacharyya, Dolon; Deighan, Justin; Jain, Sonal; Chaffin, Michael; Thiemann, Edward; Schneider, Nick; Jakosky, Bruce

2017-10-01

The enhanced ratio of deuterium to hydrogen on Mars has been widely interpreted as indicating the loss of a large column of water into space, and the hydrogen content of the upper atmosphere is now known to be highly variable. The variation in the properties of both deuterium and hydrogen in the upper atmosphere of Mars is indicative of the dynamical processes that produce these species and propagate them to altitudes where they can escape the planet. Understanding the seasonal variability of D is key to understanding the variability of the escape rate of water from Mars. Data from a 15 month observing campaign, made by the Mars Atmosphere and Volatile Evolution Imaging Ultraviolet Spectrograph high-resolution echelle channel, are used to determine the brightness of deuterium as observed at the limb of Mars. The D emission is highly variable, with a peak in brightness just after southern summer solstice. The trends of D brightness are examined against extrinsic as well as intrinsic sources. It is found that the fluctuations in deuterium brightness in the upper atmosphere of Mars (up to 400 km), corrected for periodic solar variations, vary on timescales that are similar to those of water vapor fluctuations lower in the atmosphere (20-80 km). The observed variability in deuterium may be attributed to seasonal factors such as regional dust storm activity and subsequent circulation lower in the atmosphere.

Submolecular regulation of cell transformation by deuterium depleting water exchange reactions in the tricarboxylic acid substrate cycle.

PubMed

Boros, László G; D'Agostino, Dominic P; Katz, Howard E; Roth, Justine P; Meuillet, Emmanuelle J; Somlyai, Gábor

2016-02-01

The naturally occurring isotope of hydrogen ((1)H), deuterium ((2)H), could have an important biological role. Deuterium depleted water delays tumor progression in mice, dogs, cats and humans. Hydratase enzymes of the tricarboxylic acid (TCA) cycle control cell growth and deplete deuterium from redox cofactors, fatty acids and DNA, which undergo hydride ion and hydrogen atom transfer reactions. A model is proposed that emphasizes the terminal complex of mitochondrial electron transport chain reducing molecular oxygen to deuterium depleted water (DDW); this affects gluconeogenesis as well as fatty acid oxidation. In the former, the DDW is thought to diminish the deuteration of sugar-phosphates in the DNA backbone, helping to preserve stability of hydrogen bond networks, possibly protecting against aneuploidy and resisting strand breaks, occurring upon exposure to radiation and certain anticancer chemotherapeutics. DDW is proposed here to link cancer prevention and treatment using natural ketogenic diets, low deuterium drinking water, as well as DDW production as the mitochondrial downstream mechanism of targeted anti-cancer drugs such as Avastin and Glivec. The role of (2)H in biology is a potential missing link to the elusive cancer puzzle seemingly correlated with cancer epidemiology in western populations as a result of excessive (2)H loading from processed carbohydrate intake in place of natural fat consumption. Published by Elsevier Ltd.

Carbon impurities behavior and its impact on ion thermal confinement in high-ion-temperature deuterium discharges on the Large Helical Device

NASA Astrophysics Data System (ADS)

Mukai, K.; Nagaoka, K.; Takahashi, H.; Yokoyama, M.; Murakami, S.; Nakano, H.; Ida, K.; Yoshinuma, M.; Seki, R.; Kamio, S.; Fujiwara, Y.; Oishi, T.; Goto, M.; Morita, S.; Morisaki, T.; Osakabe, M.; LHD Experiment Group1, the

2018-07-01

The behavior of carbon impurities in deuterium plasmas and its impact on thermal confinement were investigated in comparison with hydrogen plasmas in the Large Helical Device (LHD). Deuterium plasma experiments have been started in the LHD and high-ion-temperature plasmas with central ion temperature (T i) of 10 keV were successfully obtained. The thermal confinement improvement could be sustained for a longer time compared with hydrogen plasmas. An isotope effect was observed in the time evolution of the carbon density profiles. A transiently peaked profile was observed in the deuterium plasmas due to the smaller carbon convection velocity and diffusivity in the deuterium plasmas compared with the hydrogen plasmas. The peaked carbon density profile was strongly correlated to the ion thermal confinement improvement. The peaking of the carbon density profile will be one of the clues to clarify the unexplained mechanisms for the formations of ion internal transport barrier and impurity hole on LHD. These results could also lead to a better understanding of the isotope effect in the thermal confinement in torus plasma.

Effect of wetting on nucleation and growth of D2 in confinement

NASA Astrophysics Data System (ADS)

Zepeda-Ruiz, L. A.; Sadigh, B.; Shin, S. J.; Kozioziemski, B. J.; Chernov, A. A.

2018-04-01

We have performed a computational study to determine how the wetting of liquid deuterium to the walls of the material influences nucleation. We present the development of a pair-wise interatomic potential that includes zero-point motion of molecular deuterium. Deuterium is used in this study because of its importance to inertial confinement fusion and the potential to generate a superfluid state if the solidification can be suppressed. Our simulations show that wetting dominates undercooling compared to the pore geometries. We observe a transition from heterogeneous nucleation at the confining wall to homogeneous nucleation at the bulk of the liquid (and intermediate cases) as the interaction with the confining wall changes from perfect wetting to non-wetting. When nucleation is heterogeneous, the temperature needed for solidification changes by 4 K with decreasing deuterium-wall interaction, but it remains independent (and equal to the one from bulk samples) when homogeneous nucleation dominates. We find that growth and quality of the resulting microstructure also depends on the magnitude of liquid deuterium-wall interaction strength.

A Deuterium NMR Study of Bent-Core Liquid Crystals. 1; Synthesis and Characterization of Deuterium-Labeled Oxadiazole-Containing Liquid Crystals

NASA Technical Reports Server (NTRS)

Dingemans, Theo J.; Madsen, Louis A.; Samulski, Edward T.; Bushnell, Dennis M. (Technical Monitor)

2002-01-01

We have synthesized two deuterated boomerang-shaped liquid crystals based on 2,5-bis(4-hydroxyphenyl)-1,3,4-oxadiazole (ODBP). Deuterium was introduced in the rigid 2,5-diphenyl-1,3,4-oxadiazole core and in the aromatic ring of the terminal 4-dodecyloxyphenyl moiety using standard acid catalyzed deuterium exchange conditions. Both compounds, ([4,4'(1,3,4-oxadiazole-2,5-diyl-d4)] di-4-dodecyloxybenzoate: ODBP-d4-Ph-O-C12) and ([4,4'(1,3,4-oxadiazole-2,5-diyl)] di-4-dodecyloxy-benzoate-d4; ODBP-Ph-d4-O-C12) were investigated by nuclear magnetic resonance, optical microscopy and differential scanning calorimetry. The optical textures and thermal behavior of both compounds were found to be identical to the non-deuterated analog [4,4(1,3,4-oxadiazole-2,5-diyl)] di-4-dodecyloxybenzoate (ODBP-Ph-O-C12) which we reported earlier. These compounds exhibit behavior indicative of a biaxial nematic liquid crystal phase, which we hope to confirm using deuterium NMR spectroscopy in the next phase of this study.

Efficient Neutron Production from a Novel Configuration of Deuterium Gas-Puff Z-Pinch

NASA Astrophysics Data System (ADS)

Klir, D.; Kubes, P.; Rezac, K.; Cikhardt, J.; Kravarik, J.; Sila, O.; Shishlov, A. V.; Kovalchuk, B. M.; Ratakhin, N. A.; Kokshenev, V. A.; Labetsky, A. Yu.; Cherdizov, R. K.; Fursov, F. I.; Kurmaev, N. E.; Dudkin, G. N.; Nechaev, B. A.; Padalko, V. N.; Orcikova, H.; Turek, K.

2014-03-01

A novel configuration of a deuterium z pinch has been used to generate fusion neutrons. Injecting an outer hollow cylindrical plasma shell around an inner deuterium gas puff, neutron yields from DD reactions reached Yn=(2.9±0.3)×1012 at 700 ns implosion time and 2.7 MA current. Such a neutron yield means a tenfold increase in comparison with previous deuterium gas puff experiments at the same current generator. The increase of beam-target yields was obtained by a larger amount of current assembled on the z-pinch axis, and subsequently by higher induced voltage and higher energies of deuterons. A stack of CR-39 track detectors on the z-pinch axis showed hydrogen ions up to 38 MeV. Maximum neutron energies of 15 and 22 MeV were observed by radial and axial time-of-flight detectors, respectively. The number of DD neutrons per one joule of stored plasma energy approached 5×107. This implies that deuterium gas puff z pinches belong to the most efficient plasma-based sources of DD neutrons.

Visualization of water transport into soybean nodules by Tof-SIMS cryo system.

PubMed

Iijima, Morio; Watanabe, Toshimasa; Yoshida, Tomoharu; Kawasaki, Michio; Kato, Toshiyuki; Yamane, Koji

2015-04-15

This paper examined the route of water supply into soybean nodules through the new visualization technique of time of flight secondary ion mass spectrometry (Tof-SIMS) cryo system, and obtained circumstantial evidence for the water inflow route. The maximum resolution of the Tof-SIMS imaging used by this study was 1.8 μm (defined as the three pixel step length), which allowed us to detect water movement at the cellular level. Deuterium-labeled water was supplied to soybean plants for 4h and the presence of deuterium in soybean nodules was analyzed by the Tof-SIMS cryo system. Deuterium ions were found only in the endodermis tissue surrounding the central cylinder in soybean nodules. Neither xylem vessels nor phloem complex itself did not indicate any deuterium accumulation. Deuterium-ion counts in the endodermis tissue were not changed by girdling treatment, which restricted water movement through the phloem complex. The results strongly indicated that nodule tissues did not receive water directly from the phloem complex, but received water through root cortex apoplastic pathway from the root axis. Copyright © 2015 Elsevier GmbH. All rights reserved.

The DD Cold Fusion-Transmutation Connection

NASA Astrophysics Data System (ADS)

Chubb, Talbot A.

2005-12-01

LENR theory must explain dd fusion, alpha-addition transmutations, radiationless nuclear reactions, and three-body nuclear particle reactions. Reaction without radiation requires many-body D Bloch+ periodicity in both location and internal structure dependencies. Electron scattering leads to mixed quantum states. The radiationless dd fusion reaction is 2-D Bloch+ -> {}4 He Bloch2+. Overlap between {}4 He Bloch2+ and surface Cs leads to alpha absorption. In the Iwamura et al. studies active deuterium is created by scattering at diffusion barriers.

Nuclear spin polarized H and D by means of spin-exchange optical pumping

NASA Astrophysics Data System (ADS)

Stenger, Jörn; Grosshauser, Carsten; Kilian, Wolfgang; Nagengast, Wolfgang; Ranzenberger, Bernd; Rith, Klaus; Schmidt, Frank

1998-01-01

Optically pumped spin-exchange sources for polarized hydrogen and deuterium atoms have been demonstrated to yield high atomic flow and high electron spin polarization. For maximum nuclear polarization the source has to be operated in spin temperature equilibrium, which has already been demonstrated for hydrogen. In spin temperature equilibrium the nuclear spin polarization PI equals the electron spin polarization PS for hydrogen and is even larger than PS for deuterium. We discuss the general properties of spin temperature equilibrium for a sample of deuterium atoms. One result are the equations PI=4PS/(3+PS2) and Pzz=PSṡPI, where Pzz is the nuclear tensor polarization. Furthermore we demonstrate that the deuterium atoms from our source are in spin temperature equilibrium within the experimental accuracy.

EFFECTS OF HEAVY WATER ON POLIOVIRUS MULTIPLICATION: RESULTS AND SPECULATIONS ON MECHANISM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kritchevsky, D.; Carp, R.I.; Koprowski, H.

1961-07-15

The CHAT strain of type I polio virus was grown on monkey kidney cell monolayers maintained in normal growth medium, in deuterium oxide, and irradiated by 300 r of x radiation. Duplicate cultures were kept at 35 and 40 deg C. Preliminary observations indicated the effect of deuterium oxide on plague size is more pronounced than that of x rays. Different plaque ratios were obtained for virus grown in deuterium oxide at 37 and 40 deg C. Mechanisms by which deuterium oxide influenced virus growth appeared to involve the extent of randomization of the virus structure and to be manifestmore » either by altering the stability of the hydrogen bonding in the molecule or by affecting the transition temperature of the helix-random coil transformation. (C.H.)« less

Conformational Assessment of Adnectin and Adnectin-Drug Conjugate by Hydrogen/Deuterium Exchange Mass Spectrometry

NASA Astrophysics Data System (ADS)

Huang, Richard Y.-C.; O'Neil, Steven R.; Lipovšek, Daša; Chen, Guodong

2018-05-01

Higher-order structure (HOS) characterization of therapeutic protein-drug conjugates for comprehensive assessment of conjugation-induced protein conformational changes is an important consideration in the biopharmaceutical industry to ensure proper behavior of protein therapeutics. In this study, conformational dynamics of a small therapeutic protein, adnectin 1, together with its drug conjugate were characterized by hydrogen/deuterium exchange mass spectrometry (HDX-MS) with different spatial resolutions. Top-down HDX allows detailed assessment of the residue-level deuterium content in the payload conjugation region. HDX-MS dataset revealed the ability of peptide-based payload/linker to retain deuterium in HDX experiments. Combined results from intact, top-down, and bottom-up HDX indicated no significant conformational changes of adnectin 1 upon payload conjugation. [Figure not available: see fulltext.

X-Ray-induced Deuterium Enrichment of N-rich Organics in Protoplanetary Disks: An Experimental Investigation Using Synchrotron Light

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gavilan, Lisseth; Carrasco, Nathalie; Remusat, Laurent

The deuterium enrichment of organics in the interstellar medium, protoplanetary disks, and meteorites has been proposed to be the result of ionizing radiation. The goal of this study is to simulate and quantify the effects of soft X-rays (0.1–2 keV), an important component of stellar radiation fields illuminating protoplanetary disks, on the refractory organics present in the disks. We prepared tholins, nitrogen-rich organic analogs to solids found in several astrophysical environments, e.g., Titan’s atmosphere, cometary surfaces, and protoplanetary disks, via plasma deposition. Controlled irradiation experiments with soft X-rays at 0.5 and 1.3 keV were performed at the SEXTANTS beamline ofmore » the SOLEIL synchrotron, and were immediately followed by ex-situ infrared, Raman, and isotopic diagnostics. Infrared spectroscopy revealed the preferential loss of singly bonded groups (N–H, C–H, and R–N≡C) and the formation of sp{sup 3} carbon defects with signatures at ∼1250–1300 cm{sup −1}. Raman analysis revealed that, while the length of polyaromatic units is only slightly modified, the introduction of defects leads to structural amorphization. Finally, tholins were measured via secondary ion mass spectrometry to quantify the D, H, and C elemental abundances in the irradiated versus non-irradiated areas. Isotopic analysis revealed that significant D-enrichment is induced by X-ray irradiation. Our results are compared to previous experimental studies involving the thermal degradation and electron irradiation of organics. The penetration depth of soft X-rays in μ m-sized tholins leads to volume rather than surface modifications: lower-energy X-rays (0.5 keV) induce a larger D-enrichment than 1.3 keV X-rays, reaching a plateau for doses larger than 5 × 10{sup 27} eV cm{sup −3}. Synchrotron fluences fall within the expected soft X-ray fluences in protoplanetary disks, and thus provide evidence of a new non-thermal pathway to deuterium fractionation of organic matter.« less

Carbon-containing compounds on fusion-related surfaces: Thermal and ion-induced formation and erosion

NASA Astrophysics Data System (ADS)

Linsmeier, Christian

2004-12-01

The deposition of carbon on metals is the unavoidable consequence of the application of different wall materials in present and future fusion experiments like ITER. Presently used and prospected materials besides carbon (CFC materials in high heat load areas) are tungsten and beryllium. The simultaneous application of different materials leads to the formation of surface compounds due to the erosion, transport and re-deposition of material during plasma operations. The formation and erosion processes are governed by widely varying surface temperatures and kinetic energies as well as the spectrum of impinging particles from the plasma. The knowledge of the dependence on these parameters is crucial for the understanding and prediction of the compound formation on wall materials. The formation of surface layers is of great importance, since they not only determine erosion rates, but also influence the ability of the first wall for hydrogen isotope inventory accumulation and release. Surface compound formation, diffusion and erosion phenomena are studied under well-controlled ultra-high vacuum conditions using in-situ X-ray photoelectron spectroscopy (XPS) and ion beam analysis techniques available at a 3 MV tandem accelerator. XPS provides chemical information and allows distinguishing elemental and carbidic phases with high surface sensitivity. Accelerator-based spectroscopies provide quantitative compositional analysis and sensitivity for deuterium in the surface layers. Using these techniques, the formation of carbidic layers on metals is studied from room temperature up to 1700 K. The formation of an interfacial carbide of several monolayers thickness is not only observed for metals with exothermic carbide formation enthalpies, but also in the cases of Ni and Fe which form endothermic carbides. Additional carbon deposited at 300 K remains elemental. Depending on the substrate, carbon diffusion into the bulk starts at elevated temperatures together with additional carbide formation. Depending on the bond nature in the carbide (metallic in the transition metal carbides, ionic e.g. in Be2C), the surface carbide layer is dissolved upon further increased temperatures or remains stable. Carbide formation can also be initiated by ion bombardment, both of chemically inert noble gas ions or C+ or CO+ ions. In the latter case, a deposition-erosion equilibrium develops which leads to a ternary surface layer of constant thickness. A chemical erosion channel is also discussed for the enhanced erosion of thin carbon films on metals by deuterium ions.

Periodic striations on beryllium and tungsten surfaces by indirect femtosecond laser irradiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lungu, C. P.; Ticoş, C. M., E-mail: catalin.ticos@inflpr.ro; Poroşnicu, C.

2014-03-10

Femtosecond laser pulses with λ = 800 nm were focused in air at one atmosphere and in deuterium (D) at low pressure. Submicron periodic structures were observed on surfaces made of Be, W and a mixture of Be-W immersed in these gases and placed nearly parallel with the laser beam, at 300 μm from the focal spot. In air, no structures were observed on Be. For the Be-W mixture, the periodic structures were uniform and parallel when formed in D but irregular in air. In this last case the striations were organized into small patches of 1 to 2 μm in size.

Deuterium diffusion and retention in tungsten coated with barrier layer during ion irradiation

NASA Astrophysics Data System (ADS)

Begrambekov, L. B.; Kaplevsky, A. S.; Dovganyuk, S. S.; Evsin, A. E.; Baryshnikova, I. E.

2017-12-01

The results of the comparative analysis of low-temperature desorption of deuterium from tungsten coated with aluminum and yttrium films under the irradiation by hydrogen plasma with oxygen impurity are presented. The irradiation of aluminum or yttrium coating by H2+1%O2 plasma leads to the desorption of implanted deuterium from the samples. It was shown that the number of atoms desorbed depends on the sign of enthalpy of hydrogen solution in the metal film.

Apparatus for producing laser targets

DOEpatents

Jarboe, T.R.; Baker, W.R.

1975-09-23

This patent relates to an apparatus and method for producing deuterium targets or pellets of 25u to 75u diameter. The pellets are sliced from a continuously spun solid deuterium thread at a rate of up to 10 pellets/second. The pellets after being sliced from the continuous thread of deuterium are collimated and directed to a point of use, such as a laser activated combustion or explosion chamber wherein the pellets are imploded by laser energy or laser produced target plasmas for neutral beam injection. (auth)

Analytic, empirical and delta method temperature derivatives of D-D and D-T fusion reactivity formulations, as a means of verification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Langenbrunner, James R.; Booker, Jane M.

We examine the derivatives with respect to temperature, for various deuterium-tritium (DT) and deuterium-deuterium (D-D) fusion-reactivity formulations. Langenbrunner and Makaruk [1] had studied this as a means of understanding the time and temperature domain of reaction history measured in dynamic fusion experiments. Presently, we consider the temperature derivative dependence of fusion reactivity as a means of exercising and verifying the consistency of the various reactivity formulations.

Neutron streaming studies along JET shielding penetrations

NASA Astrophysics Data System (ADS)

Stamatelatos, Ion E.; Vasilopoulou, Theodora; Batistoni, Paola; Obryk, Barbara; Popovichev, Sergey; Naish, Jonathan

2017-09-01

Neutronic benchmark experiments are carried out at JET aiming to assess the neutronic codes and data used in ITER analysis. Among other activities, experiments are performed in order to validate neutron streaming simulations along long penetrations in the JET shielding configuration. In this work, neutron streaming calculations along the JET personnel entrance maze are presented. Simulations were performed using the MCNP code for Deuterium-Deuterium and Deuterium- Tritium plasma sources. The results of the simulations were compared against experimental data obtained using thermoluminescence detectors and activation foils.

SERS imaging of cell-surface biomolecules metabolically labeled with bioorthogonal Raman reporters.

PubMed

Xiao, Ming; Lin, Liang; Li, Zefan; Liu, Jie; Hong, Senlian; Li, Yaya; Zheng, Meiling; Duan, Xuanming; Chen, Xing

2014-08-01

Live imaging of biomolecules with high specificity and sensitivity as well as minimal perturbation is essential for studying cellular processes. Here, we report the development of a bioorthogonal surface-enhanced Raman scattering (SERS) imaging approach that exploits small Raman reporters for visualizing cell-surface biomolecules. The cells were cultured and imaged by SERS microscopy on arrays of Raman-enhancing nanoparticles coated on silicon wafers or glass slides. The Raman reporters including azides, alkynes, and carbondeuterium bonds are small in size and spectroscopically bioorthogonal (background-free). We demonstrated that various cell-surface biomolecules including proteins, glycans, and lipids were metabolically incorporated with the corresponding precursors bearing a Raman reporter and visualized by SERS microscopy. The coupling of SERS microscopy with bioorthogonal Raman reporters expands the capabilities of live-cell microscopy beyond the modalities of fluorescence and label-free imaging. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Experiments with lithium limiter on T-11M tokamak and applications of the lithium capillary-pore system in future fusion reactor devices

NASA Astrophysics Data System (ADS)

Mirnov, S. V.; Azizov, E. A.; Evtikhin, V. A.; Lazarev, V. B.; Lyublinski, I. E.; Vertkov, A. V.; Prokhorov, D. Yu

2006-06-01

The paper is an overview of recent results of Li limiter testing in T-11M tokamak. The lithium limiter is based on the capillary-pore system (CPS) concept. The Li erosion process and deuterium (D2) and helium (He) sorption by Li first wall were investigated. The ability of capillary forces to confine the liquid Li in the CPS limiter during disruption was demonstrated. The idea of combined lithium limiter with thin (0.6 mm) CPS coating as a solution of the heat removal problem was realized. As a result the quasi steady-state tokamak regime with duration up to 0.3 s and clean (Zeff = 1) deuterium plasma has been achieved. The temporal evolution of the lithium surface temperature during discharge was measured by a IR radiometer and then was recalculated to the surface power load. For the estimation of the Li limiter erosion the Li neutral and ions spectral line emission were observed. The increase in lithium erosion as a result of limiter heating was discovered. The radial distribution of plasma column radiation measurements showed up to 90% of the total radiation losses in a relatively thin (5 cm) boundary layer and only 10% in a plasma centre during discharges with high Li influx. Oscillations of Li emission and saw-tooth-like oscillations of the limiter surface temperature have been detected in discharge regimes with highest Li limiter temperature (>600 °C). A version of Li CPS first wall of DEMO reactor and Li CPS limiter experiment in the International Thermonuclear Energy Reactor are suggested.

Analysis of phosphoinositide 3-kinase inhibitors by bottom-up electron-transfer dissociation hydrogen/deuterium exchange mass spectrometry

PubMed Central

Masson, Glenn R.; Maslen, Sarah L.

2017-01-01

Until recently, one of the major limitations of hydrogen/deuterium exchange mass spectrometry (HDX-MS) was the peptide-level resolution afforded by proteolytic digestion. This limitation can be selectively overcome through the use of electron-transfer dissociation to fragment peptides in a manner that allows the retention of the deuterium signal to produce hydrogen/deuterium exchange tandem mass spectrometry (HDX-MS/MS). Here, we describe the application of HDX-MS/MS to structurally screen inhibitors of the oncogene phosphoinositide 3-kinase catalytic p110α subunit. HDX-MS/MS analysis is able to discern a conserved mechanism of inhibition common to a range of inhibitors. Owing to the relatively minor amounts of protein required, this technique may be utilised in pharmaceutical development for screening potential therapeutics. PMID:28381646

Measurement of quasi-isentropic compressibility of helium and deuterium at pressures of 1500-2000 GPa

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mochalov, M. A., E-mail: postmaster@ifv.vniief.ru; Il'kaev, R. I.; Fortov, V. E.

2012-10-15

The quasi-isentropic compressibility of helium and deuterium plasmas at pressures of up to 1500-2000 GPa has been measured using devices with spherical geometry and an X-ray diagnostic complex comprising three betatrons and a multichannel imaging system with electro-optic gamma detectors. A deuterium density of 4.5 g/cm{sup 3} and a helium density of 3.8 g/cm{sup 3} have been obtained at pressures of 2210 and 1580 GPa, respectively. The internal energy of a deuterium plasma at the indicated pressure is about 1 MJ/cm{sup 3}, which is about 100 times greater than the specific energy of condensed chemical explosives. Analysis of the obtainedmore » data shows that the degree of helium ionization under the achieved plasma compression parameters is about 0.9.« less

Characterisation of deuterium spectra from laser driven multi-species sources by employing differentially filtered image plate detectors in Thomson spectrometers.

PubMed

Alejo, A; Kar, S; Ahmed, H; Krygier, A G; Doria, D; Clarke, R; Fernandez, J; Freeman, R R; Fuchs, J; Green, A; Green, J S; Jung, D; Kleinschmidt, A; Lewis, C L S; Morrison, J T; Najmudin, Z; Nakamura, H; Nersisyan, G; Norreys, P; Notley, M; Oliver, M; Roth, M; Ruiz, J A; Vassura, L; Zepf, M; Borghesi, M

2014-09-01

A novel method for characterising the full spectrum of deuteron ions emitted by laser driven multi-species ion sources is discussed. The procedure is based on using differential filtering over the detector of a Thompson parabola ion spectrometer, which enables discrimination of deuterium ions from heavier ion species with the same charge-to-mass ratio (such as C(6+), O(8+), etc.). Commonly used Fuji Image plates were used as detectors in the spectrometer, whose absolute response to deuterium ions over a wide range of energies was calibrated by using slotted CR-39 nuclear track detectors. A typical deuterium ion spectrum diagnosed in a recent experimental campaign is presented, which was produced from a thin deuterated plastic foil target irradiated by a high power laser.

Characterisation of deuterium spectra from laser driven multi-species sources by employing differentially filtered image plate detectors in Thomson spectrometers

NASA Astrophysics Data System (ADS)

Alejo, A.; Kar, S.; Ahmed, H.; Krygier, A. G.; Doria, D.; Clarke, R.; Fernandez, J.; Freeman, R. R.; Fuchs, J.; Green, A.; Green, J. S.; Jung, D.; Kleinschmidt, A.; Lewis, C. L. S.; Morrison, J. T.; Najmudin, Z.; Nakamura, H.; Nersisyan, G.; Norreys, P.; Notley, M.; Oliver, M.; Roth, M.; Ruiz, J. A.; Vassura, L.; Zepf, M.; Borghesi, M.

2014-09-01

A novel method for characterising the full spectrum of deuteron ions emitted by laser driven multi-species ion sources is discussed. The procedure is based on using differential filtering over the detector of a Thompson parabola ion spectrometer, which enables discrimination of deuterium ions from heavier ion species with the same charge-to-mass ratio (such as C6 +, O8 +, etc.). Commonly used Fuji Image plates were used as detectors in the spectrometer, whose absolute response to deuterium ions over a wide range of energies was calibrated by using slotted CR-39 nuclear track detectors. A typical deuterium ion spectrum diagnosed in a recent experimental campaign is presented, which was produced from a thin deuterated plastic foil target irradiated by a high power laser.

Quasi-Isentropic Compressibility of Deuterium at a Pressure of 12 TPa

NASA Astrophysics Data System (ADS)

Mochalov, M. A.; Il'kaev, R. I.; Fortov, V. E.; Mikhailov, A. L.; Arinin, V. A.; Blikov, A. O.; Komrakov, V. A.; Maksimkin, I. P.; Ogorodnikov, V. A.; Ryzhkov, A. V.

2018-04-01

An experimental result for the quasi-isentropic compressibility of a strongly nonideal deuterium plasma compressed in a spherical device by the pressure P = 11400 GPa (114 Mbar) to the density ρ ≈ 10g/cm3 has been reported. The characteristics of the experimental device, diagnostic methods, and experimental results have been described. The trajectory of motion of metallic shells compressing a deuterium plasma has been recorded using intense pulsed sources of X rays with the boundary energy of electrons up to 60 MeV. The deuterium plasma density ρ ≈ 10g/cm3 has been determined from the measured radius of the shell at the time of its "stop." The pressure of the compressed plasma has been determined from gas-dynamic calculations taking into account the real characteristics of the experimental device.

Influence of displacement damage on deuterium and helium retention in austenitic and ferritic-martensitic alloys considered for ADS service

NASA Astrophysics Data System (ADS)

Voyevodin, V. N.; Karpov, S. A.; Kopanets, I. E.; Ruzhytskyi, V. V.; Tolstolutskaya, G. D.; Garner, F. A.

2016-01-01

The behavior of ion-implanted hydrogen (deuterium) and helium in austenitic 18Cr10NiTi stainless steel, EI-852 ferritic steel and ferritic/martensitic steel EP-450 and their interaction with displacement damage were investigated. Energetic argon irradiation was used to produce displacement damage and bubble formation to simulate nuclear power environments. The influence of damage morphology and the features of radiation-induced defects on deuterium and helium trapping in structural alloys was studied using ion implantation, the nuclear reaction D(3He,p)4He, thermal desorption spectrometry and transmission electron microscopy. It was found in the case of helium irradiation that various kinds of helium-radiation defect complexes are formed in the implanted layer that lead to a more complicated spectra of thermal desorption. Additional small changes in the helium spectra after irradiation with argon ions to a dose of ≤25 dpa show that the binding energy of helium with these traps is weakly dependent on the displacement damage. It was established that retention of deuterium in ferritic and ferritic-martensitic alloys is three times less than in austenitic steel at damage of ∼1 dpa. The retention of deuterium in steels is strongly enhanced by presence of radiation damages created by argon ion irradiation, with a shift in the hydrogen release temperature interval of 200 K to higher temperature. At elevated temperatures of irradiation the efficiency of deuterium trapping is reduced by two orders of magnitude.

Hydrogen isotope separation utilizing bulk getters

DOEpatents

Knize, R.J.; Cecchi, J.L.

1991-08-20

Tritium and deuterium are separated from a gaseous mixture thereof, derived from a nuclear fusion reactor or some other source, by providing a casing with a bulk getter therein for absorbing the gaseous mixture to produce an initial loading of the getter, partially desorbing the getter to produce a desorbed mixture which is tritium-enriched, pumping the desorbed mixture into a separate container, the remaining gaseous loading in the getter being deuterium-enriched, desorbing the getter to a substantially greater extent to produce a deuterium-enriched gaseous mixture, and removing the deuterium-enriched mixture into another container. The bulk getter may comprise a zirconium-aluminum alloy, or a zirconium-vanadium-iron alloy. The partial desorption may reduce the loading by approximately fifty percent. The basic procedure may be extended to produce a multistage isotope separator, including at least one additional bulk getter into which the tritium-enriched mixture is absorbed. The second getter is then partially desorbed to produce a desorbed mixture which is further tritium-enriched. The last-mentioned mixture is then removed from the container for the second getter, which is then desorbed to a substantially greater extent to produce a desorbed mixture which is deuterium-enriched. The last-mentioned mixture is then removed so that the cycle can be continued and repeated. The method of isotope separation is also applicable to other hydrogen isotopes, in that the method can be employed for separating either deuterium or tritium from normal hydrogen. 4 figures.

Hydrogen isotope separation utilizing bulk getters

DOEpatents

Knize, Randall J.; Cecchi, Joseph L.

1991-01-01

Tritium and deuterium are separated from a gaseous mixture thereof, derived from a nuclear fusion reactor or some other source, by providing a casing with a bulk getter therein for absorbing the gaseous mixture to produce an initial loading of the getter, partially desorbing the getter to produce a desorbed mixture which is tritium-enriched, pumping the desorbed mixture into a separate container, the remaining gaseous loading in the getter being deuterium-enriched, desorbing the getter to a substantially greater extent to produce a deuterium-enriched gaseous mixture, and removing the deuterium-enriched mixture into another container. The bulk getter may comprise a zirconium-aluminum alloy, or a zirconium-vanadium-iron alloy. The partial desorption may reduce the loading by approximately fifty percent. The basic procedure may be extended to produce a multistage isotope separator, including at least one additional bulk getter into which the tritium-enriched mixture is absorbed. The second getter is then partially desorbed to produce a desorbed mixture which is further tritium-enriched. The last-mentioned mixture is then removed from the container for the second getter, which is then desorbed to a substantially greater extent to produce a desorbed mixture which is deuterium-enriched. The last-mentioned mixture is then removed so that the cycle can be continued and repeated. The method of isotope separation is also applicable to other hydrogen isotopes, in that the method can be employed for separating either deuterium or tritium from normal hydrogen.

Hydrogen isotope separation utilizing bulk getters

DOEpatents

Knize, Randall J.; Cecchi, Joseph L.

1990-01-01

Tritium and deuterium are separated from a gaseous mixture thereof, derived from a nuclear fusion reactor or some other source, by providing a casing with a bulk getter therein for absorbing the gaseous mixture to produce an initial loading of the getter, partially desorbing the getter to produce a desorbed mixture which is tritium-enriched, pumping the desorbed mixture into a separate container, the remaining gaseous loading in the getter being deuterium-enriched, desorbing the getter to a substantially greater extent to produce a deuterium-enriched gaseous mixture, and removing the deuterium-enriched mixture into another container. The bulk getter may comprise a zirconium-aluminum alloy, or a zirconium-vanadium-iron alloy. The partial desorption may reduce the loading by approximately fifty percent. The basic procedure may be extended to produce a multistage isotope separator, including at least one additional bulk getter into which the tritium-enriched mixture is absorbed. The second getter is then partially desorbed to produce a desorbed mixture which is further tritium-enriched. The last-mentioned mixture is then removed from the container for the second getter, which is then desorbed to a substantially greater extent to produce a desorbed mixture which is deuterium-enriched. The last-mentioned mixture is then removed so that the cycle can be continued and repeated. The method of isotope separation is also applicable to other hydrogen isotopes, in that the method can be employed for separating either deuterium or tritium from normal hydrogen.

Localizing Carbohydrate Binding Sites in Proteins Using Hydrogen/Deuterium Exchange Mass Spectrometry

NASA Astrophysics Data System (ADS)

Zhang, Jingjing; Kitova, Elena N.; Li, Jun; Eugenio, Luiz; Ng, Kenneth; Klassen, John S.

2016-01-01

The application of hydrogen/deuterium exchange mass spectrometry (HDX-MS) to localize ligand binding sites in carbohydrate-binding proteins is described. Proteins from three bacterial toxins, the B subunit homopentamers of Cholera toxin and Shiga toxin type 1 and a fragment of Clostridium difficile toxin A, and their interactions with native carbohydrate receptors, GM1 pentasaccharides (β-Gal-(1→3)-β-GalNAc-(1→4)[α-Neu5Ac-(2→3)]-β-Gal-(1→4)-Glc), Pk trisaccharide (α-Gal-(1→4)-β-Gal-(1→4)-Glc) and CD-grease (α-Gal-(1→3)-β-Gal-(1→4)-β-GlcNAcO(CH2)8CO2CH3), respectively, served as model systems for this study. Comparison of the differences in deuterium uptake for peptic peptides produced in the absence and presence of ligand revealed regions of the proteins that are protected against deuterium exchange upon ligand binding. Notably, protected regions generally coincide with the carbohydrate binding sites identified by X-ray crystallography. However, ligand binding can also result in increased deuterium exchange in other parts of the protein, presumably through allosteric effects. Overall, the results of this study suggest that HDX-MS can serve as a useful tool for localizing the ligand binding sites in carbohydrate-binding proteins. However, a detailed interpretation of the changes in deuterium exchange upon ligand binding can be challenging because of the presence of ligand-induced changes in protein structure and dynamics.

A dual origin for water in carbonaceous asteroids revealed by CM chondrites

NASA Astrophysics Data System (ADS)

Piani, Laurette; Yurimoto, Hisayoshi; Remusat, Laurent

2018-04-01

Carbonaceous asteroids represent the principal source of water in the inner Solar System and might correspond to the main contributors for the delivery of water to Earth. Hydrogen isotopes in water-bearing primitive meteorites, for example carbonaceous chondrites, constitute a unique tool for deciphering the sources of water reservoirs at the time of asteroid formation. However, fine-scale isotopic measurements are required to unravel the effects of parent-body processes on the pre-accretion isotopic distributions. Here, we report in situ micrometre-scale analyses of hydrogen isotopes in six CM-type carbonaceous chondrites, revealing a dominant deuterium-poor water component (δD = -350 ± 40‰) mixed with deuterium-rich organic matter. We suggest that this deuterium-poor water corresponds to a ubiquitous water reservoir in the inner protoplanetary disk. A deuterium-rich water signature has been preserved in the least altered part of the Paris chondrite (δDParis ≥ -69 ± 163‰) in hydrated phases possibly present in the CM rock before alteration. The presence of the deuterium-enriched water signature in Paris might indicate that transfers of ice from the outer to the inner Solar System were significant within the first million years of the history of the Solar System.

Fusion product losses due to fishbone instabilities in deuterium JET plasmas

NASA Astrophysics Data System (ADS)

Kiptily, V. G.; Fitzgerald, M.; Goloborodko, V.; Sharapov, S. E.; Challis, C. D.; Frigione, D.; Graves, J.; Mantsinen, M. J.; Beaumont, P.; Garcia-Munoz, M.; Perez von Thun, C.; Rodriguez, J. F. R.; Darrow, D.; Keeling, D.; King, D.; McClements, K. G.; Solano, E. R.; Schmuck, S.; Sips, G.; Szepesi, G.; Contributors, JET

2018-01-01

During development of a high-performance hybrid scenario for future deuterium-tritium experiments on the Joint European Torus, an increased level of fast ion losses in the MeV energy range was observed during the instability of high-frequency n  =  1 fishbones. The fishbones are excited during deuterium neutral beam injection combined with ion cyclotron heating. The frequency range of the fishbones, 10-25 kHz, indicates that they are driven by a resonant interaction with the NBI-produced deuterium beam ions in the energy range  ⩽120 keV. The fast particle losses in a much higher energy range are measured with a fast ion loss detector, and the data show an expulsion of deuterium plasma fusion products, 1 MeV tritons and 3 MeV protons, during the fishbone bursts. An MHD mode analysis with the MISHKA code combined with the nonlinear wave-particle interaction code HAGIS shows that the loss of toroidal symmetry caused by the n  =  1 fishbones affects strongly the confinement of non-resonant high energy fusion-born tritons and protons by perturbing their orbits and expelling them. This modelling is in a good agreement with the experimental data.

Universes without the weak force: Astrophysical processes with stable neutrons

NASA Astrophysics Data System (ADS)

Grohs, E.; Howe, Alex R.; Adams, Fred C.

2018-02-01

We investigate a class of universes in which the weak interaction is not in operation. We consider how astrophysical processes are altered in the absence of weak forces, including big bang nucleosynthesis (BBN), galaxy formation, molecular cloud assembly, star formation, and stellar evolution. Without weak interactions, neutrons no longer decay, and the universe emerges from its early epochs with a mixture of protons, neutrons, deuterium, and helium. The baryon-to-photon ratio must be smaller than the canonical value in our Universe to allow free nucleons to survive the BBN epoch without being incorporated into heavier nuclei. At later times, the free neutrons readily combine with protons to make deuterium in sufficiently dense parts of the interstellar medium, and provide a power source before they are incorporated into stars. Almost all of the neutrons are incorporated into deuterium nuclei before stars are formed. As a result, stellar evolution proceeds primarily through strong interactions, with deuterium first burning into helium, and then helium fusing into carbon. Low-mass deuterium-burning stars can be long-lived, and higher-mass stars can synthesize the heavier elements necessary for life. Although somewhat different from our own, such universes remain potentially habitable.

Mechanistic studies of the metabolic chiral inversion of (R)-ibuprofen in humans

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baillie, T.A.; Adams, W.J.; Kaiser, D.G.

1989-05-01

The metabolic chiral inversion of R-(-)-ibuprofen has been studied in human subjects by means of specific deuterium labeling and stereoselective gas chromatography-mass spectrometry methodology. After simultaneous p.o. administration of a mixture of R-(-)-ibuprofen (300 mg) and R-(-)-(3,3,3-2H3)ibuprofen (304 mg) to four adult male volunteers, the enantiomeric composition and deuterium content of the drug in serum, and of the drug and its principal metabolites in urine, were followed over a period of 24 hr. The results of these analyses indicated that: (1) conversion of R-(-)- to S-(+)-ibuprofen takes place with complete retention of deuterium at the beta-methyl (C-3) position; (2) chiralmore » inversion of R-(-)-(2H3)ibuprofen is not subject to a discernible deuterium isotope effect; and (3) replacement of the beta-methyl hydrogen atoms by deuterium has no effect on any of the serum pharmacokinetic parameters for R-(-)- or S-(+)-ibuprofen. These data indicate that the process whereby R-(-)-ibuprofen undergoes metabolic inversion in human subjects does not involve 2,3-dehydroibuprofen as an intermediate, and that the underlying mechanism cannot, therefore, entail a desaturation/reduction sequence.« less

Water Sorption and Vapor-Phase Deuterium Exchange Studies on Methemoglobin CC, SC, SS, AS, and AA

PubMed Central

Killion, Philip J.; Cameron, Bruce F.

1972-01-01

Five hemoglobins whose genetic relationship to one another involves one set of alleles, hemoglobins CC, SC, SS, AS, and AA, were studied in the Met form. Two different investigations were conducted at 28°C on these methemoglobins within a McBain gravimetric sorption system: sorption of H2O vapor and vapor-phase deuterium-hydrogen exchange. For each of the five samples there was close agreement between the per cent hydration of polar sites as determined from sorption studies and the maximum per cent of labile hydrogens that were exchanged during the vapor-phase deuterium exchange study. Both studies measured a slight increase in the number of polar sites accessible to H2O or D2O vapor for those samples in which the substituent in the sixth position from the N-terminus of the two β-chains had a positively charged side chain and a slight decrease for those in which the substituent had a negatively charged side chain. The in-exchange of deuterium for hydrogen occurred at a faster observed rate than the out-exchange of hydrogen for deuterium. PMID:5030563

Biotechnological Patents Applications of the Deuterium Oxide in Human Health.

PubMed

da S Mariano, Reysla M; Bila, Wendell C; Trindade, Maria Jaciara F; Lamounier, Joel A; Galdino, Alexsandro S

2017-01-01

Deuterium oxide is a molecule that has been used for decades in several studies related to human health. Currently, studies on D2O have mobilized a "Race for Patenting" worldwide. Several patents have been registered from biomedical and technological studies of D2O showing the potential of this stable isotope in industry and health care ecosystems. Most of the patents related to the applications of the deuterium oxide in human health have been summarized in this review. The following patents databases were consulted: European Patent Office (Espacenet), the United States Patent and Trademark Office (USPTO), the United States Latin America Patents (LATIPAT), Patent scope -Search International and National Patent Collections (WIPO), Google Patents and Free Patents Online. With this review, the information was collected on recent publications including 22 patents related to deuterium oxide and its applications in different areas. This review showed that deuterium oxide is a promising component in different areas, including biotechnology, chemistry and medicine. In addition, the knowledge of this compound was covered, reinforcing its importance in the field of biotechnology and human health. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Cytology is advanced by studying effects of deuterium environment

NASA Technical Reports Server (NTRS)

Bose, S.; Crespi, H. L.; Flaumenhaft, E.; Katz, J. J.

1967-01-01

Research of deuterium effects on biological systems shows deuteriation is not incompatible with life. With the successful cultivation of deuteriated bacteria, work is now being done on extraction of deuterio-compounds from bacteria.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ryan, John James

The E665 spectrometer at Fermila.b measured Deep-Inelastic Scattering of 490 GeV /c muons off several targets: Hydrogen, Deuterium, and Xenon. Events were selected from the Xenon and Deuterium targets, with a range of energy exchange,more » $$\

Cryogenic target formation using cold gas jets

DOEpatents

Hendricks, C.D.

1980-02-26

A method and apparatus using cold gas jets for producing a substantially uniform layer of cryogenic materials on the inner surface of hollow spherical members having one or more layers, such as inertially imploded targets are disclosed. By vaporizing and quickly refreezing cryogenic materials contained within a hollow spherical member, a uniform layer of the materials is formed on an inner surface of the spherical member. Basically the method involves directing cold gas jets onto a spherical member having one or more layers or shells and containing the cryogenic material, such as a deuterium-tritium (DT) mixture, to freeze the contained material, momentarily heating the spherical member so as to vaporize the contained material, and quickly refreezing the thus vaporized material forming a uniform layer of cryogenic material on an inner surface of the spherical member. 4 figs.

Deuterium: Natural variations used as a biological tracer

USGS Publications Warehouse

Gleason, J.D.; Friedman, I.

1970-01-01

The suggestion is made that isotope tracing be carried out by monitoring the natural variations in deuterium concentrations. As an example, the natural variations in deuterium concentrations between food and water collected in Illinois and food and water collected in Colorado were used to determine the residence time of water in the blood and urine of rats. We observed not only a 51/2-day turnover time of water in the blood and urine, but also evidence for the influx of water vapor from the atmosphere through the lungs into the blood.

Research on laser-removal of a deuterium deposit from a graphite sample

NASA Astrophysics Data System (ADS)

Kubkowska, M.; Skladnik-Sadowska, E.; Malinowski, K.; Sadowski, M. J.; Rosinski, M.; Gasior, P.

2014-04-01

The paper presents experimental results of investigation of a removal of deuterium deposits from a graphite target by means of pulsed laser beams. The sample was a part of the TEXTOR limiter with a deuterium-deposited layer. That target was located in the vacuum chamber, pumped out to 5×10-5 Torr, and it was irradiated with a Nd:YAG laser, which generated 3.5-ns pulses of energy of 0.5 J at λ1 = 1063 nm, or 0.1 J at λ3 = 355 nm.

Generation of Mie size microdroplet aerosols with applications in laser-driven fusion experiments.

PubMed

Higginbotham, A P; Semonin, O; Bruce, S; Chan, C; Maindi, M; Donnelly, T D; Maurer, M; Bang, W; Churina, I; Osterholz, J; Kim, I; Bernstein, A C; Ditmire, T

2009-06-01

We have developed a tunable source of Mie scale microdroplet aerosols that can be used for the generation of energetic ions. To demonstrate this potential, a terawatt Ti:Al2O3 laser focused to 2 x 10(19) W/cm2 was used to irradiate heavy water (D2O) aerosols composed of micron-scale droplets. Energetic deuterium ions, which were generated in the laser-droplet interaction, produced deuterium-deuterium fusion with approximately 2 x 10(3) fusion neutrons measured per joule of incident laser energy.

Buscopan labeled with carbon-14 and deuterium.

PubMed

Latli, Bachir; Stiasni, Michael; Hrapchak, Matt; Li, Zhibin; Grinberg, Nelu; Lee, Heewon; Busacca, Carl A; Senanayake, Chris H

2016-11-01

Hyosine butyl bromide, the active ingredient in Buscopan, is an anticholinergic and antimuscarinic drug used to treat pain and discomfort caused by abdominal cramps. A straightforward synthesis of carbon-14- and deuterium-labeled Buscopan was developed using scopolamine, n-butyl-1- 14 C bromide, and n-butyl- 2 H 9 bromide, respectively. In a second carbon-14 synthesis, the radioactive carbon was incorporated in the tropic acid moiety to follow its metabolism. Herein, we describe the detailed preparations of carbon-14- and deuterium-labeled Buscopan. Copyright © 2016 John Wiley & Sons, Ltd.

Isotopic effects in the muon transfer from pmu and dmu to heavier atoms.

PubMed

Dupays, Arnaud

2004-07-23

The results of accurate hyperspherical calculations of the muon-transfer rates from muonic protium and deuterium atoms to nitrogen, oxygen, and neon are reported. Very good agreement with measured rates is obtained and, for the three systems, the isotopic effect is perfectly reproduced. The transfer rate is higher for deuterium in the cases of nitrogen and neon due to constructive interferences between two transfer paths. The lower transfer rate for deuterium in the case of oxygen results from a large resonant contribution. Copyright 2004 The American Physical Society

An isotope-dilution standard GC/MS/MS method for steroid hormones in water

USGS Publications Warehouse

Foreman, William T.; Gray, James L.; ReVello, Rhiannon C.; Lindley, Chris E.; Losche, Scott A.

2013-01-01

An isotope-dilution quantification method was developed for 20 natural and synthetic steroid hormones and additional compounds in filtered and unfiltered water. Deuterium- or carbon-13-labeled isotope-dilution standards (IDSs) are added to the water sample, which is passed through an octadecylsilyl solid-phase extraction (SPE) disk. Following extract cleanup using Florisil SPE, method compounds are converted to trimethylsilyl derivatives and analyzed by gas chromatography with tandem mass spectrometry. Validation matrices included reagent water, wastewater-affected surface water, and primary (no biological treatment) and secondary wastewater effluent. Overall method recovery for all analytes in these matrices averaged 100%; with overall relative standard deviation of 28%. Mean recoveries of the 20 individual analytes for spiked reagent-water samples prepared along with field samples analyzed in 2009–2010 ranged from 84–104%, with relative standard deviations of 6–36%. Detection levels estimated using ASTM International’s D6091–07 procedure range from 0.4 to 4 ng/L for 17 analytes. Higher censoring levels of 100 ng/L for bisphenol A and 200 ng/L for cholesterol and 3-beta-coprostanol are used to prevent bias and false positives associated with the presence of these analytes in blanks. Absolute method recoveries of the IDSs provide sample-specific performance information and guide data reporting. Careful selection of labeled compounds for use as IDSs is important because both inexact IDS-analyte matches and deuterium label loss affect an IDS’s ability to emulate analyte performance. Six IDS compounds initially tested and applied in this method exhibited deuterium loss and are not used in the final method.

Deuterium chemistry in the young massive protostellar core NGC 2264 CMM3

NASA Astrophysics Data System (ADS)

Awad, Z.; Shalabiea, O. M.

2018-01-01

In this work we present the first attempt of modelling the deuterium chemistry in the massive young protostellar core NGC 2264 CMM3. We investigated the sensitivity of this chemistry to the physical conditions in its surrounding environment. The results showed that deuteration, in the protostellar gas, is affected by variations in the core density, the amount of gas depletion onto grain surfaces, the CR ionisation rate, but it is insensitive to variations in the H2 ortho-to-para ratio. Our results, also, showed that deuteration is often enhanced in less-dense, partially depleted (<85%), or cores that are exerted to high CR ionisation rates (≥6.5×10^{-17} s^{-1}). However, in NGC 2264 CMM3, decreasing the amount of gas depleted onto grains and enhancing the CR ionisation rate are often overestimating the observed values in the core. The best fit time to observations occurs around (1-5) × 104 yrs for core densities in the range (1-5)×106 cm^{-3} with CR ionisation rate between (1.7-6.5)×10^{-17} s^{-1}. These values are in agreement with the results of the most recent theoretical chemical model of CMM3, and the time range of best fit is, also, in-line with the estimated age of young protostellar objects. We conclude that deuterium chemistry in protostellar cores is: (i) sensitive to variations in the physical conditions in its environment, (ii) insensitive to changes in the H2 ortho-to-para ratio. We also conclude that the core NGC 2264 CMM3 is in its early stages of chemical evolution with an estimated age of (1-5)×104 yrs.

Synthesis of deuterium labeled ketamine metabolite dehydronorketamine-d₄.

PubMed

Sulake, Rohidas S; Chen, Chinpiao; Lin, Huei-Ru; Lua, Ahai-Chang

2011-10-01

A convenient synthesis of ketamine metabolite dehydronorketamine-d(4), starting from commercially available deuterium labeled bromochlorobenzene, was achieved. Key steps include Grignard reaction, regioselective hydroxybromination, Staudinger reduction, and dehydrohalogenation. Copyright © 2011 Elsevier Ltd. All rights reserved.

Polarized deuterium internal target at AmPS (NIKHEF)

NASA Astrophysics Data System (ADS)

Ferro-Luzzi, M.; Zhou, Z.-L.; van den Brand, J. F. J.; Bulten, H. J.; Alarcon, R.; van Bakel, N.; Botto, T.; Bouwhuis, M.; van Buuren, L.; Comfort, J.; Doets, M.; Dolfini, S.; Ent, R.; Geurts, D.; Heimberg, P.; Higinbotham, D. W.; de Jager, C. W.; Lang, J.; de Lange, D. J.; Norum, B.; Passchier, I.; Poolman, H. R.; Six, E.; Steijger, J.; Szczerba, D.; Unal, O.; de Vries, H.

1998-01-01

We describe the polarized deuterium target internal to the NIKHEF medium-energy electron storage ring. Tensor polarized deuterium was produced in an atomic beam source and injected into a storage cell target. A Breit-Rabi polarimeter was used to monitor the injected atomic beam intensity and polarization. An electrostatic ion-extraction system and a Wien filter were utilized to measure on-line the atomic fraction of the target gas in the storage cell. This device was supplemented with a tensor polarization analyzer using the neutron anisotropy of the 3H(d,n)α reaction at 60 keV. This method allows determining the density-averaged nuclear polarization of the target gas, independent of spatial and temporal variations. We address issues important for polarized hydrogen/deuterium internal targets, such as the effects of spin-exchange collisions and resonant transitions induced by the RF fields of the charged particle beam.

Highly Nuclear-Spin-Polarized Deuterium Atoms from the UV Photodissociation of Deuterium Iodide.

PubMed

Sofikitis, Dimitris; Glodic, Pavle; Koumarianou, Greta; Jiang, Hongyan; Bougas, Lykourgos; Samartzis, Peter C; Andreev, Alexander; Rakitzis, T Peter

2017-06-09

We report a novel highly spin-polarized deuterium (SPD) source, via the photodissociation of deuterium iodide at 270 nm. I(^{2}P_{3/2}) photofragments are ionized with m-state selectivity, and their velocity distribution measured via velocity-map slice imaging, from which the D polarization is determined. The process produces ∼100% electronically polarized D at the time of dissociation, which is then converted to ∼60% nuclear D polarization after ∼1.6  ns. These production times for SPD allow collision-limited densities of ∼10^{18}  cm^{-3} and at production rates of ∼10^{21}  s^{-1} which are 10^{6} and 10^{4} times higher than conventional (Stern-Gerlach separation) methods, respectively. We discuss the production of SPD beams, and combining high-density SPD with laser fusion, to investigate polarized D-T, D-^{3}He, and D-D fusion.

Laser microprobe and resonant laser ablation for depth profile measurements of hydrogen isotope atoms contained in graphite.

PubMed

Yorozu, M; Yanagida, T; Nakajyo, T; Okada, Y; Endo, A

2001-04-20

We measured the depth profile of hydrogen atoms in graphite by laser microprobing combined with resonant laser ablation. Deuterium-implanted graphite was employed for the measurements. The sample was ablated by a tunable laser with a wavelength corresponding to the resonant wavelength of 1S-2S of deuterium with two-photon excitation. The ablated deuterium was ionized by a 2 + 1 resonant ionization process. The ions were analyzed by a time-of-flight mass spectrometer. The deuterium ions were detected clearly with the resonant ablation. The detection limit was estimated to be less than 10(16) atoms/cm(3) in our experiments. We determined the depth profile by considering the etching profile and the etching rate. The depth profile agreed well with Monte Carlo simulations to within a precision of 23 mum for the center position and 4-mum precision for distributions for three different implantation depths.

Electrolytic Installation in Order to Obtain Deuterium and to Fill the Pressure Deposits; INSTALACION ELECTROLITICA PARA LA OBTENCION DE DEUTERIO Y LLENADO DE DEPOSITOS A PRESION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lopez, F.C.; Sanz, A.T.

1959-01-01

In order to obtain deuterium for the feed of accelerator ion sources, a sample and automatic electrolytic installation was constructed. The installation, used with a small compressor, can fill pressure vessels of 1 to 2 liter capacity with deuterium up to a pressure of 4 atmospheres in a few hours of operation. The electrolytic cell has a "V" shape and can operate with only 3 cc of heavy water. The electrodes are platinum and NaOH solution in the proportion of 15 wt.% is the electrolyte. The operation is automatic. The compressor is small, and the charge is low so thatmore » an auxiliary motor is not needed. The compressor piston is the only moving part. Deuterium losses are practically zero. (auth)« less

Modelling third harmonic ion cyclotron acceleration of deuterium beams for JET fusion product studies experiments

NASA Astrophysics Data System (ADS)

Schneider, M.; Johnson, T.; Dumont, R.; Eriksson, J.; Eriksson, L.-G.; Giacomelli, L.; Girardo, J.-B.; Hellsten, T.; Khilkevitch, E.; Kiptily, V. G.; Koskela, T.; Mantsinen, M.; Nocente, M.; Salewski, M.; Sharapov, S. E.; Shevelev, A. E.; Contributors, JET

2016-11-01

Recent JET experiments have been dedicated to the studies of fusion reactions between deuterium (D) and Helium-3 (3He) ions using neutral beam injection (NBI) in synergy with third harmonic ion cyclotron radio-frequency heating (ICRH) of the beam. This scenario generates a fast ion deuterium tail enhancing DD and D3He fusion reactions. Modelling and measuring the fast deuterium tail accurately is essential for quantifying the fusion products. This paper presents the modelling of the D distribution function resulting from the NBI+ICRF heating scheme, reinforced by a comparison with dedicated JET fast ion diagnostics, showing an overall good agreement. Finally, a sawtooth activity for these experiments has been observed and interpreted using SPOT/RFOF simulations in the framework of Porcelli’s theoretical model, where NBI+ICRH accelerated ions are found to have a strong stabilizing effect, leading to monster sawteeth.

Field ionization characteristics of an ion source array for neutron generators

NASA Astrophysics Data System (ADS)

Bargsten Johnson, B.; Schwoebel, P. R.; Resnick, P. J.; Holland, C. E.; Hertz, K. L.; Chichester, D. L.

2013-11-01

A new deuterium ion source is being developed to improve the performance of existing compact neutron generators. The ion source is a microfabricated array of metal tips with an integrated gate (i.e., grid) and produces deuterium ions by field ionizing (or field desorbing) a supply of deuterium gas. Deuterium field ion currents from arrays at source temperatures of 77 K and 293 K are studied. Ion currents from single etched-wire tips operating under the same conditions are used to help understand array results. I-F characteristics of the arrays were found to follow trends similar to those of the better understood single etched-wire tip results; however, the fields achieved by the arrays are limited by electrical breakdown of the structure. Neutron production by field ionization at 293 K was demonstrated for the first time from microfabricated array structures with integrated gates.

Deuterium dilution technique for body composition assessment: resolving methodological issues in children with moderate acute malnutrition.

PubMed

Fabiansen, Christian; Yaméogo, Charles W; Devi, Sarita; Friis, Henrik; Kurpad, Anura; Wells, Jonathan C

2017-08-01

Childhood malnutrition is highly prevalent and associated with high mortality risk. In observational and interventional studies among malnourished children, body composition is increasingly recognised as a key outcome. The deuterium dilution technique has generated high-quality data on body composition in studies of infants and young children in several settings, but its feasibility and accuracy in children suffering from moderate acute malnutrition requires further study. Prior to a large nutritional intervention trial among children with moderate acute malnutrition, we conducted pilot work to develop and adapt the deuterium dilution technique. We refined procedures for administration of isotope doses and collection of saliva. Furthermore, we established that equilibration time in local context is 3 h. These findings and the resulting standard operating procedures are important to improve data quality when using the deuterium dilution technique in malnutrition studies in field conditions, and may encourage a wider use of isotope techniques.

Polarized deuterium internal target at AmPS (NIKHEF)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Norum, Blaine; De Jager, Cornelis; Geurts, D.

1997-08-01

We describe the polarized deuterium target internal to the NIKHEF medium-energy electron storage ring. Tensor polarized deuterium was produced in an atomic beam source and injected into a storage cell target. A Breit-Rabi polarimeter was used to monitor the injected atomic beam intensity and polarization. An electrostatic ion-extraction system and a Wien filter were utilized to measure on-line the atomic fraction of the target gas in the storage cell. This device was supplemented with a tensor polarization analyzer using the neutron anisotropy of the 3H(d,n)sigma reaction at 60 keV. This method allows determining the density-averaged nuclear polarization of the targetmore » gas, independent of spatial and temporal variations. We address issues important for polarized hydrogen/deuterium internal targets, such as the effects of spin-exchange collisions and resonant transitions induced by the RF fields of the charged particle beam.« less

Polarized deuterium internal target at AmPS (NIKHEF)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ferro-Luzzi, M.; NIKHEF, P.O. Box 41882, 1009 DB Amsterdam; Zhou, Z.-L.

1998-01-20

We describe the polarized deuterium target internal to the NIKHEF medium-energy electron storage ring. Tensor polarized deuterium was produced in an atomic beam source and injected into a storage cell target. A Breit-Rabi polarimeter was used to monitor the injected atomic beam intensity and polarization. An electrostatic ion-extraction system and a Wien filter were utilized to measure on-line the atomic fraction of the target gas in the storage cell. This device was supplemented with a tensor polarization analyzer using the neutron anisotropy of the {sup 3}H(d,n){alpha} reaction at 60 keV. This method allows determining the density-averaged nuclear polarization of themore » target gas, independent of spatial and temporal variations. We address issues important for polarized hydrogen/deuterium internal targets, such as the effects of spin-exchange collisions and resonant transitions induced by the RF fields of the charged particle beam.« less

Defect annealing and thermal desorption of deuterium in low dose HFIR neutron-irradiated tungsten

NASA Astrophysics Data System (ADS)

Shimada, Masashi; Hara, Masanori; Otsuka, Teppei; Oya, Yasuhisa; Hatano, Yuji

2015-08-01

Three tungsten samples irradiated at High Flux Isotope Reactor at Oak Ridge National Laboratory were exposed to deuterium plasma (ion fluence of 1 × 1026 m-2) at three different temperatures (100, 200, and 500 °C) in Tritium Plasma Experiment at Idaho National Laboratory. Subsequently, thermal desorption spectroscopy was performed with a ramp rate of 10 °C min-1 up to 900 °C, and the samples were annealed at 900 °C for 0.5 h. These procedures were repeated three times to uncover defect-annealing effects on deuterium retention. The results show that deuterium retention decreases approximately 70% for at 500 °C after each annealing, and radiation damages were not annealed out completely even after the 3rd annealing. TMAP modeling revealed the trap concentration decreases approximately 80% after each annealing at 900 °C for 0.5 h.

First result of deuterium retention in neutron-irradiated tungsten exposed to high flux plasma in TPE

NASA Astrophysics Data System (ADS)

Shimada, Masashi; Hatano, Y.; Calderoni, P.; Oda, T.; Oya, Y.; Sokolov, M.; Zhang, K.; Cao, G.; Kolasinski, R.; Sharpe, J. P.

2011-08-01

With the Japan-US joint research project Tritium, Irradiations, and Thermofluids for America and Nippon (TITAN), an initial set of tungsten samples (99.99% purity, A.L.M.T. Co.) were irradiated by high flux neutrons at 323 K to 0.025 dpa in High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL). Subsequently, one of the neutron-irradiated tungsten samples was exposed to a high-flux deuterium plasma (ion flux: 5 × 1021 m-2 s-1, ion fluence: 4 × 1025 m-2) in the Tritium Plasma Experiment (TPE) at Idaho National Laboratory (INL). The deuterium retention in the neutron-irradiated tungsten was 40% higher in comparison to the unirradiated tungsten. The observed broad desorption spectrum from neutron-irradiated tungsten and associated TMAP modeling of the deuterium release suggest that trapping occurs in the bulk material at more than three different energy sites.

Enzymatic preparation of. cap alpha. - and. beta. -deuterated or tritiated amino acids with l-methionine. gamma. -lyase

DOE Office of Scientific and Technical Information (OSTI.GOV)

Esaki, N.; Sawada, S.; Tanaka, H.

L-Methionine ..gamma..-lyase catalyzes the exchange of ..cap alpha..- and ..beta..-hydrogens of L-methionine and S-methyl-L-cysteine with deuterium or tritium of solvents. The rate of ..cap alpha..-hydrogen exchange with deuterium was about 40 times faster than that of the elimination reactions. The deuterium and tritium were exchanged also with the ..cap alpha..- and ..beta..-hydrogens of the straight-chain amino acids which do not undergo the elimination: L-alanine, L-..cap alpha..-aminobutyrate, L-norvaline, and L-norleucine. No exchange occurs for the D-isomers, acidic L-amino acids, basic L-amino acids, and branched-chain L-amino acids, although ..cap alpha..-hydrogen of glycine, L-trypotophan, and L-phenylalanine is exchanged slowly. These enzymatic hydrogen-exchange reactionsmore » facilitate specific labeling of the L-amino acids with deuterium and tritium.« less

Efficient source for the production of ultradense deuterium D(-1) for laser-induced fusion (ICF).

PubMed

Andersson, Patrik U; Lönn, Benny; Holmlid, Leif

2011-01-01

A novel source which simplifies the study of ultradense deuterium D(-1) is now described. This means one step further toward deuterium fusion energy production. The source uses internal gas feed and D(-1) can now be studied without time-of-flight spectral overlap from the related dense phase D(1). The main aim here is to understand the material production parameters, and thus a relatively weak laser with focused intensity ≤10(12) W cm(-2) is employed for analyzing the D(-1) material. The properties of the D(-1) material at the source are studied as a function of laser focus position outside the emitter, deuterium gas feed, laser pulse repetition frequency and laser power, and temperature of the source. These parameters influence the D(-1) cluster size, the ionization mode, and the laser fragmentation patterns.

Operation and commissioning of IFMIF (International Fusion Materials Irradiation Facility) LIPAc injector.

PubMed

Okumura, Y; Gobin, R; Knaster, J; Heidinger, R; Ayala, J-M; Bolzon, B; Cara, P; Chauvin, N; Chel, S; Gex, D; Harrault, F; Ichimiya, R; Ihara, A; Ikeda, Y; Kasugai, A; Kikuchi, T; Kitano, T; Komata, M; Kondo, K; Maebara, S; Marqueta, A; O'Hira, S; Perez, M; Phillips, G; Pruneri, G; Sakamoto, K; Scantamburlo, F; Senée, F; Shinto, K; Sugimoto, M; Takahashi, H; Usami, H; Valette, M

2016-02-01

The objective of linear IFMIF prototype accelerator is to demonstrate 125 mA/CW deuterium ion beam acceleration up to 9 MeV. The injector has been developed in CEA Saclay and already demonstrated 140 mA/100 keV deuterium beam [R. Gobin et al., Rev. Sci. Instrum. 85, 02A918 (2014)]. The injector was disassembled and delivered to the International Fusion Energy Research Center in Rokkasho, Japan. After reassembling the injector, commissioning has started in 2014. Up to now, 100 keV/120 mA/CW hydrogen and 100 keV/90 mA/CW deuterium ion beams have been produced stably from a 10 mm diameter extraction aperture with a low beam emittance of 0.21 π mm mrad (rms, normalized). Neutron production by D-D reaction up to 2.4 × 10(9) n/s has been observed in the deuterium operation.

Surface cracking and melting of different tungsten grades under transient heat and particle loads in a magnetized coaxial plasma gun

NASA Astrophysics Data System (ADS)

Kikuchi, Y.; Sakuma, I.; Iwamoto, D.; Kitagawa, Y.; Fukumoto, N.; Nagata, M.; Ueda, Y.

2013-07-01

Surface damage of pure tungsten (W), W alloys with 2 wt.% tantalum (W-Ta) and vacuum plasma spray (VPS) W coating on a reduced activation material of ferritic steel (F82H) due to repetitive ELM-like pulsed (˜0.3 ms) deuterium plasma irradiation has been investigated by using a magnetized coaxial plasma gun. Surface cracks appeared on a pure W sample exposed to 10 plasma pulses of ˜0.3 MJ m-2, while a W-Ta sample did not show surface cracks with similar pulsed plasma irradiation. The energy density threshold for surface cracking was significantly increased by the existence of the alloying element of tantalum. No surface morphology change of a VPS W coated F82H sample was observed under 10 plasma pulses of ˜0.3 MJ m-2, although surface melting and cracks in the resolidification layer occurred at higher energy density of ˜0.9 MJ m-2. There was no indication of exfoliation of the W coating from the substrate of F82H after the pulsed plasma exposures.

The biophysical effects of deuterium oxide on biomolecules and living cells through open notebook science

NASA Astrophysics Data System (ADS)

Salvagno, Anthony L.

This dissertation explores various effects of deuterium oxide (D2O also known as heavy water) in nature. Water is everywhere and interacts with just about everything. As such, it would be quite a daunting task to characterize every effect that water exhibits on everything in the universe. This research is a small piece of the puzzle, and provides some fundamental understanding of how water interacts with other molecules. This is done from two viewpoints: (1) the effects of heavy water on living cells and (2) the effects of heavy water on molecules. Varying concentrations of deuterium oxide were used as the growing solvent for four different organisms: S. cerevisiae, E. coli, A. thaliana, and N. tabacum. In each case growth rates and morphology was assessed and compared to the wild type. Organisms were surveyed for potential phenotypes exhibited in the presence of extremely low and high concentrations of D2O. In every organism, growth is increasingly inhibited in higher concentrations of D2O compared to lower concentrations of D2O. In the case of tobacco, a root hair phenotype was exhibited in the presence of deuterium depleted water (<1ppm deuterium atoms). Roots also grew faster in 1% D2O and DDW, compared to natural water. For Arabidopsis, root germination is statistically indistinguishable between DI water and 33% D2O. Growth of the plant in 10% D2O is identical to that of natural water, and potentially healthier. Meanwhile, plants grown in 60% D2O exhibit slower growth and leaf discoloration. Tests on E. coli reveal inconsistent growth rates, but exhibit increased growth in DDW when adapted to D2O. Cellular and colonial morphology is also very distinguished from the wt. Cells appear to remain joined after cellular fission, while colonies exhibit brainy structures. Yeast morphology is quite different. Yeast cells remain joined after mitosis in 99% D2O, causing large cellular aggregates, while colonies become slightly asymmetric. Adaptation of yeast to D2O was not possible. Molecular effects were examined using a variety of tools including: dynamic light spectroscopy, Fourier transform-infrared spectroscopy, cavity ring-down spectroscopy, and optical tweezers. Heat induced protein aggregation was possible in H2O, but prevented in the presence of D2O and analyzed via DLS. Deuterium exchange and replacement was observed and quantified using both FT-IR and CRDS. With FT-IR it was possible to identify differences between solvents, while the time-scale of hydrogen-deuterium exchange was quantified for bulk water with CRDS. Using optical tweezers, DNA was overstretched in both H2O and D2O. The average force for DNA overstretching was found to be ~2.5pN higher in D2O compared to H2O. Deuterium oxide has a stabilizing force on biomolecules, which prevents protein denaturing and can affect the timing for cellular processes. It is because of this molecular property that D2O is observed to affect organisms grown with D2O instead of H2O. Despite this, there seems to be an optimal concentration of deuterium which is above the natural concentration of 155.6ppm. In the presence of deuterium depleted water, cells exhibit signs of stress, further demonstrating that deuterium isn't merely tolerated in solution, but actually required as hypothesized by Gilbert N. Lewis in 1934.

Observer for a thick layer of solid deuterium-tritium using backlit optical shadowgraphy and interferometry.

PubMed

Choux, Alexandre; Busvelle, Eric; Gauthier, Jean Paul; Pascal, Ghislain

2007-11-20

Our work is in the context of the French "laser mégajoule" project, about fusion by inertial confinement. The project leads to the problem of characterizing the inner surface, of the approximately spherical target, by optical shadowgraphy techniques. Our work is entirely based on the basic idea that optical shadowgraphy produces "caustics" of systems of optical rays, which contain a great deal of 3D information about the surface to be characterized. We develop a method of 3D reconstruction based upon this idea plus a "small perturbations" technique. Although computations are made in the special "spherical" case, the method is in fact general and may be extended to several other situations.

Static Chemistry in Disks or Clouds

NASA Astrophysics Data System (ADS)

Semenov, D.; Wiebe, D.

2006-11-01

This FORTRAN77 code can be used to model static, time-dependent chemistry in ISM and circumstellar disks. Current version is based on the OSU'06 gas-grain astrochemical network with all updates to the reaction rates, and includes surface chemistry from Hasegawa & Herbst (1993) and Hasegawa, Herbst, and Leung (1992). Surface chemistry can be modeled either with the standard rate equation approach or modified rate equation approach (useful in disks). Gas-grain interactions include sticking of neutral molecules to grains, dissociative recombination of ions on grains as well as thermal, UV, X-ray, and CRP-induced desorption of frozen species. An advanced X-ray chemistry and 3 grain sizes with power-law size distribution are also included. An deuterium extension to this chemical model is available.

Deuterium-rich Water in Meteorites

NASA Astrophysics Data System (ADS)

Deloule, E.; Robert, F.

1995-09-01

D/H ratios of 2 meteorites (Renazzo CR and Semarkona LL3), which are known to exhibit the largest departures from the terrestrial hydrogen isotopic ratios, have been determined with the CRPG Nancy ion-microprobe. Correlations between the D/H ratios and the chemical compositions (H2O, K, Si, C/H) of plausible hydrogen carriers were observed. From these correlations, it is possible to show that, contrary to previous interpretations, phyllosilicates are the carriers of the deuterium-rich hydrogen in Semarkona and Renazzo : 870 x10-6 D/H 670 x106 (+4600 dD 3300) and 320 x10-6 (dD 1050), respectively. Hydrogen is also present in the chondrules of these two deuterium-rich meteorites. Isotopic equilibrium between the deuterium depleted phases and the deuterium-rich phyllosilicates was never attained. This is illustrated at a micron scale by the D/H ratios obtained continuously during a 3 hours measurement on a same position (see figure below). It can be seen that water-rich mineral(s) having D/H up to 550 x10-6 (dD = +2500) are in contact with a mineral having D/H = 234 x10-6 (dD = +500). The thickness of the boundary where the diffusion of hydrogen took place is restricted to less than 0.2 mm. Such isotopic heterogeneity is quite spectacular if one remembers that the isotopic variations that we can see within these 0.2 mm are an order of magnitude larger than the total observed variations on Earth. The large differences in D/H ratios between matrix (up to 700 x 10-6, dD up to +3500) and chondrules (from 120 x10-6 (dD = -230) to 230 x10-6 (dD = +475)) show that hydrogen in chondrules cannot originate from the matrix by simple contamination or diffusion processes. The high D/H ratios measured in water bearing minerals could not have been produced thermally within a dense solar nebula. Chemical reactions (i.e. involving ions or radicals), taking place in interstellar space or in the outer regions of the nebula at 110-140K are presently the only conceivable mechanisms capable of yielding such isotopic enrichments. Hydrogen isotopic composition and water concentration versus depth in the matrix of Semarkona. The profile was obtained by sputtering the minerals with the primary beam of the ion-probe (0 stands for the surface mineral). Note the complete lack of isotopic homogenisation between the hydrogen bearing phases : the D/H ratio increases within 0.2 mm by more than 300x10-6; that is one order of magnitude larger than the total variations on Earth. Such a distribution demonstrates that no secondary processes altered the pristine isotopic ratios established at the time of mineral formation.

Facility and Methods Developed for Simulated Space Vacuum Ultraviolet Exposure Testing of Polymer Films

NASA Technical Reports Server (NTRS)

Dever, Joyce A.; Pietromica, Anthony J.; Stueber, Thomas J.; Sechkar, Edward A.; Messer, Russell K.

2002-01-01

Vacuum ultraviolet (VUV) radiation of wavelengths between 115 and 200 nm produced by the Sun in the space environment can degrade polymer films, producing changes in their optical, mechanical, and chemical properties. These effects are particularly important for thin polymer films being considered for ultralightweight space structures, because, for most polymers, VUV radiation is absorbed in a thin surface layer. The NASA Glenn Research Center has developed facilities and methods for long-term ground testing of polymer films to evaluate space environmental VUV radiation effects. VUV exposure can also be used as part of combined or sequential simulated space environmental exposures to determine combined damaging effects with other aspects of the space environment, which include solar ultraviolet radiation, solar flare x-rays, electron and proton radiation, atomic oxygen (for low-Earth-orbit missions), and temperature effects. Because the wavelength sensitivity of VUV damage is not well known for most materials, Glenn's VUV facility uses a broad-spectrum deuterium lamp with a magnesium fluoride window that provides output between 115 and 200 nm. Deuterium lamps of this type were characterized by the National Institute of Standards and Technology and through measurements at Glenn. Spectral irradiance measurements show that from approximately 115 to 160 nm, deuterium lamp irradiance can be many times that of air mass zero solar irradiance, and as wavelength increases above approximately 160 nm, deuterium lamp irradiance decreases in comparison to the Sun. The facility is a cryopumped vacuum chamber that achieves a system pressure of approximately 5310(exp -6) torr. It contains four individual VUV-exposure compartments in vacuum, separated by water-cooled copper walls to minimize VUV radiation and any sample contamination cross interactions between compartments. Each VUV-exposure compartment contains a VUV deuterium lamp, a motor-controlled sample stage coupled with a moveable cesium iodide VUV phototube, and two thermocouples for temperature measurement. The vacuum chamber and exterior equipment is shown. Each VUV lamp is located at the top of the chamber with its projection-tube pushed through an O-ring compression fitting. The lamp assemblies are located on ports that can be isolated from the rest of the vacuum chamber, permitting maintenance or replacement of the lamps without breaking vacuum in the main chamber where the samples are located. A view of two of the four interior VUV-exposure compartments, including the moveable sample stages and detector holders is also shown. Glenn is using this facility to support testing of Next Generation Space Telescope sunshield materials that is being led by the NASA Goddard Space Flight Center and to develop an understanding of the wavelength, intensity, and temperature dependence of VUV-induced polymer degradation.

Optimization and Validation of a Surface Wipe Method to Determine Cyanide and Cyanate: Application to the Emergency Destruction System

DTIC Science & Technology

2012-08-01

NJ b WC-7 Grade 42, 55 mm filter paper Whatman, Piscataway, NJ b WC-8 Cellulose nitrate membrane filter, 47 mm Whatman, Piscataway, NJ b WC-9...density polypropylene plastic bottle. 2.5 Standards Sodium cyanide (NaCN, ≥97.0%, CAS no. 143-33-9) and potassium cyanate (KOCN, ≥97.0...Agilent Technologies model 3D CE system, with an ultraviolet (deuterium lamp) diode array detector, was used to determine the quantities of CN and OCN

Compact x-ray source and panel

DOEpatents

Sampayon, Stephen E [Manteca, CA

2008-02-12

A compact, self-contained x-ray source, and a compact x-ray source panel having a plurality of such x-ray sources arranged in a preferably broad-area pixelized array. Each x-ray source includes an electron source for producing an electron beam, an x-ray conversion target, and a multilayer insulator separating the electron source and the x-ray conversion target from each other. The multi-layer insulator preferably has a cylindrical configuration with a plurality of alternating insulator and conductor layers surrounding an acceleration channel leading from the electron source to the x-ray conversion target. A power source is connected to each x-ray source of the array to produce an accelerating gradient between the electron source and x-ray conversion target in any one or more of the x-ray sources independent of other x-ray sources in the array, so as to accelerate an electron beam towards the x-ray conversion target. The multilayer insulator enables relatively short separation distances between the electron source and the x-ray conversion target so that a thin panel is possible for compactness. This is due to the ability of the plurality of alternating insulator and conductor layers of the multilayer insulators to resist surface flashover when sufficiently high acceleration energies necessary for x-ray generation are supplied by the power source to the x-ray sources.

Methods for tritium labeling

DOEpatents

Andres, Hendrik; Morimoto, Hiromi; Williams, Philip G.

1993-01-01

Reagents and processes for reductively introducing deuterium or tritium into organic molecules are described. The reagents are deuterium or tritium analogs of trialkyl boranes, borane or alkali metal aluminum hydrides. The process involves forming these reagents in situ from alkali metal tritides or deuterides.

Point-like neutron source based on high-current electron cyclotron resonance ion source with powerful millimeter wave plasma heating

NASA Astrophysics Data System (ADS)

Golubev, S. V.; Skalyga, V. A.; Izotov, I. V.; Sidorov, A. V.

2018-01-01

A possibility of an intense deuterium ion beam creation for a compact powerful point-like neutron source is discussed. The fusion takes place due to bombardment of deuterium (or tritium) loaded target by high-current focused deuterium ion beam with energy of 100 keV. The ways of high-current and low emittance ion beam formation from the plasma of quasi-gasdynamic ion source of a new generation based on an electron cyclotron resonance discharge in an open magnetic trap sustained by powerful microwave radiation are investigated.

Gas temperature measurements in deuterium hollow cathode glow discharge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Majstorović, Gordana, E-mail: gordana.majstorovic@va.mod.gov.rs; Šišović, Nikola, E-mail: nikolas@ff.bg.ac.rs

2016-03-25

We report results of optical emission spectroscopy measurements of rotational T{sub rot} and translational (gas) temperature of deuterium molecules in a hollow cathode (HC) glow discharge. The rotational temperature of excited electronic state of D{sub 2} was determined from the intensity distribution in the rotational structure of Q branch of the two Fulcher-α diagonal bands: (ν’=ν”=2) and (ν’=ν”=3). The population of excited energy levels, determined from relative line intensities, was used to derive radial rotational temperature distributions as well as gas temperature distribution of deuterium molecule.

Comment on "A centroid molecular dynamics study of liquid para hydrogen and ortho deuterium" [J. Chem. Phys. 121, 6412 (2004)].

PubMed

Miller, Thomas F; Manolopoulos, David E; Madden, Paul A; Konieczny, Martin; Oberhofer, Harald

2005-02-01

We show that the two phase points considered in the recent simulations of liquid para hydrogen by Hone and Voth lie in the liquid-vapor coexistence region of a purely classical molecular dynamics simulation. By contrast, their phase point for ortho deuterium was in the one-phase liquid region for both classical and quantum simulations. These observations are used to account for their report that quantum mechanical effects enhance the diffusion in liquid para hydrogen and decrease it in ortho deuterium.(c) 2005 American Institute of Physics.

Synthesis of 2H- and 13C-substituted dithanes

DOEpatents

Martinez, Rodolfo A.; Alvarez, Marc A.; Silks, III, Louis A.; Unkefer, Clifford J.

2003-01-01

The present invention is directed to labeled compounds, [2-.sup.13 C]dithiane wherein the .sup.13 C atom is directly bonded to one or two deuterium atoms. The present invention is also directed to processes of preparing [2-.sup.13 C]dithiane wherein the .sup.13 C atom is directly bonded to one or two deuterium atoms. The present invention is also directed to labeled compounds, e.g., [.sup.2 H.sub.1-2, .sup.13 C]methanol (arylthio)-, acetates wherein the .sup.13 C atom is directly bonded to exactly one or two deuterium atoms.

Synthesis Of 2h- And 13c-Substituted Dithanes

DOEpatents

Martinez, Rodolfo A.; Alvarez, Marc A.; Silks, III, Louis A.; Unkefer, Clifford J.

2004-05-04

The present invention is directed to labeled compounds, [2-.sup.13 C]dithane wherein the .sup.13 C atom is directly bonded to one or two deuterium atoms. The present invention is also directed to processes of preparing [2-.sup.13 C]dithane wherein the .sup.13 C atom is directly bonded to one or two deuterium atoms. The present invention is also directed to labeled compounds, e.g., [.sup.2 H.sub.1-2, .sup.13 C]methanol (arylthio)-, acetates wherein the .sup.13 C atom is directly bonded to exactly one or two deuterium atoms.

Temperature effects in accumulation of deuterium and helium at the grain boundaries of a nano-grained tungsten

NASA Astrophysics Data System (ADS)

Kaganovich, Igor; Krstic, Predrag; Startsev, Edward

2014-10-01

It has been known that defects in tungsten, in particular at the grain boundaries, are preferable sites for deuterium and helium retention. For the case of the nano-grained boundaries, we study by classical molecular dynamics the cumulative retention of deuterium and helium at impact energies below 100 eV as functions of tungsten temperature at models of the dislocation boundaries. We obtain a strong preference of the retention of the impact particles at the boundaries at high temperature of 1000 K. Support of PPPL LDRD grant acknowledged.

Coincidence charged-current neutrino-induced deuteron disintegration for 2H2 16O

NASA Astrophysics Data System (ADS)

Van Orden, J. W.; Donnelly, T. W.; Moreno, O.

2017-12-01

Semi-inclusive charge-changing neutrino reactions on targets of heavy water are investigated with the goal of determining the relative contributions to the total cross section of deuterium and oxygen in kinematics chosen to emphasize the former. The study is undertaken for conditions where the typical neutrino beam energies are in the few GeV region, and hence relativistic modeling is essential. For this, the previous relativistic approach for the deuteron is employed, together with a spectral function approach for the case of oxygen. Upon optimizing the kinematics of the final-state particles assumed to be detected (typically a muon and a proton) it is shown that the oxygen contribution to the total cross section is suppressed by roughly an order of magnitude compared with the deuterium cross section, thereby confirming that CC ν studies of heavy water can effectively yield the cross sections for deuterium, with acceptable backgrounds from oxygen. This opens the possibility of using deuterium to determine the incident neutrino flux distribution, to have it serve as a target for which the nuclear structure issues are minimal, and possibly to use deuterium to provide improved knowledge of specific aspects of hadronic structure, such as to explore the momentum transfer dependence of the isovector axial-vector form factor of the nucleon.

Development of a Twin-Screw D-2 Extruder for the ITER Pellet Injection System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meitner, Steven J; Baylor, Larry R; Carbajo, Juan J

A twin-screw extruder for the ITER pellet injection system is under development at the Oak Ridge National Laboratory. The extruder will provide a stream of solid hydrogen isotopes to a secondary section, where pellets are cut and accelerated with single-stage gas gun into the plasma. A one-fifth ITER scale prototype extruder has been built to produce a continuous solid deuterium extrusion. Deuterium gas is precooled and liquefied before being introduced into the extruder. The precooler consists of a copper vessel containing liquid nitrogen surrounded by a deuterium gas filled copper coil. The liquefier is comprised of a copper cylinder connectedmore » to a Cryomech AL330 cryocooler, which is surrounded by a copper coil that the precooled deuterium flows through. The lower extruder barrel is connected to a Cryomech GB-37 cryocooler to solidify the deuterium (at approximate to 15 K) before it is forced through the extruder nozzle. A viewport located below the extruder nozzle provides a direct view of the extrusion. A camera is used to document the extrusion quality and duration. A data acquisition system records the extruder temperatures, torque, and speed, upstream, and downstream pressures. This paper will describe the prototype twin-screw extruder and initial extrusion results.« less

Hydrogen/deuterium (H/D) exchange of gelatinized starch studied by two-dimensional (2D) near-infrared (NIR) correlation spectroscopy

NASA Astrophysics Data System (ADS)

Shinzawa, Hideyuki; Mizukado, Junji

2018-05-01

Hydrogen/deuterium (H/D) exchange of gelatinized starch was probed by in-situ near-infrared (NIR) monitoring coupled with two-dimensional (2D) correlation spectroscopy. Gelatinized starch undergoes spontaneous H/D exchange in D2O. During the substitution, the exchange rate essentially becomes different depending on solvent accessibility of various parts of the molecule. Thus, by analyzing the change in the NIR feature observed during the substitution, it becomes possible to sort out local structure and dynamics of the system. 2D correlation analysis of the time-dependent NIR spectra reveals the presence of different local structure of the starch, each having different solvent accessibility. For example, during the H/D exchange, the D2O is first absorbed by starch molecules especially around the surface area between the starch and water, where the water molecules are weakly interacted with the starch molecules. This absorption is quickly followed by the development of HDO species. Further absorption of the D2O results in the penetration of the molecules inside the starch and eventually develops the relatively strong interaction between the HDO and starch molecules because of the presence of dominant starch molecules.

Water D/H Ratio In Low-Mass Protostars

NASA Astrophysics Data System (ADS)

Persson, Magnus V.; Jørgensen, Jes K.; van Dishoeck, Ewine F.; Harsono, Daniel

2013-07-01

Water is an important molecule for our life on Earth, but its way from formation on the surfaces of dust grains to planets and the accompanying chemical processing are not well understood. Through evaporation in the warm inner regions of protostars, water brings complex organics and other species previously locked up in the ice into the gas phase. The water deuterium fractionation (HDO/H2O abundance ratio) has traditionally been used to infer the amount of water that was brought to the Earth by comets. Deducing this ratio in the warm gas of deeply-embedded low-mass protostars allows to extend the discussion of the origin of Earth's water to earlier evolutionary stages. This poster present high-angular resolution, ground based interferometric observations of both HDO and H2(18)O water isotopologues toward several Class~0 low-mass protostars. The emission is compact, and stems from the inner few 100 AU in all sources. The derived amount of deuterium fractionation in water, obtained assuming LTE and optically thin emission, is the same within the uncertainties in all sources and shows only small enhancements compared with Earth's oceans and solar system's comets.

A mechanism for large divertor plasma energy loss via lithium radiation in tokamaks

NASA Astrophysics Data System (ADS)

Rognlien, T. D.; Meier, E. T.; Soukhanovskii, V. A.

2012-10-01

Lithium has been used as a wall-conditioning element in a number of tokamaks over the years, including TFTR, FTU, and NSTX, where core plasma energy confinement and particle control are often found to improve following such conditioning. Here the possible role of Li in providing substantial energy loss for divertor plasmas via line radiation is reported. A multi-charge-state 2D UEDGE fluid model is used where the hydrogenic and Li ions and neutrals are each evolved as separate species and separate equations are solved for the electron and ion temperatures. It is shown that a sufficient level of Li neutrals evolving from the divertor surface via sputtering or evaporation can induce energy detachment of the divertor plasma, yielding a strongly radiating zone near the divertor where ionization and recombination from/to neutral Li can radiate most of the power flowing into the scrape-off layer while maintaining low core contamination. A local peaking of Li emissivity for electron temperatures near 1 eV appears to play an important role in the detachment of the mixed deuterium/Li plasma. Evidence of such behavior from NSTX discharges will be discussed.

Oxygen isotope and deuterium composition of snow cover on the profile of Western Siberia from Tomsk to the Gulf of Ob

NASA Astrophysics Data System (ADS)

Vasil'chuk, Yu. K.; Shevchenko, V. P.; Lisitzin, A. P.; Budantseva, N. A.; Vorobiov, S. N.; Kirpotin, S. N.; Krizkov, I. V.; Manasypov, R. M.; Pokrovsky, O. S.; Chizhova, Ju. N.

2016-12-01

The purpose of this work is to study the variability of the isotope composition (δ18O, δD, d exc) of the snow cover on a long transect of Western Siberia from the southern taiga to the tundra. The study of the snow cover is of paleogeographic, paleogeocryological, and paleohydrological value. The snow cover of western Siberia was sampled on a broadly NS transzonal profile from the environs of Tomsk (southern taiga zone) to the eastern coast of the Gulf of Ob (tundra zone) from February 19 to March 4, 2014. Snow samples were collected at 31 sites. Most of the samples represented by fresh snow, i.e., snow that had fallen a day before the moment of sampling were collected in two areas. In the area of Yamburg, the snow specimens collected from the surface are most probably settled snow of different ages. The values of δ18O in the snow from Tomsk to Yamburg varied from-21.89 to-32.82‰, and the values of δD, from-163.3 to-261.2‰. The value of deuterium excess was in the range of 4.06-19.53‰.

Ion beam enhancement in magnetically insulated ion diodes for high-intensity pulsed ion beam generation in non-relativistic mode

NASA Astrophysics Data System (ADS)

Zhu, X. P.; Zhang, Z. C.; Pushkarev, A. I.; Lei, M. K.

2016-01-01

High-intensity pulsed ion beam (HIPIB) with ion current density above Child-Langmuir limit is achieved by extracting ion beam from anode plasma of ion diodes with suppressing electron flow under magnetic field insulation. It was theoretically estimated that with increasing the magnetic field, a maximal value of ion current density may reach nearly 3 times that of Child-Langmuir limit in a non-relativistic mode and close to 6 times in a highly relativistic mode. In this study, the behavior of ion beam enhancement by magnetic insulation is systematically investigated in three types of magnetically insulated ion diodes (MIDs) with passive anode, taking into account the anode plasma generation process on the anode surface. A maximal enhancement factor higher than 6 over the Child-Langmuir limit can be obtained in the non-relativistic mode with accelerating voltage of 200-300 kV. The MIDs differ in two anode plasma formation mechanisms, i.e., surface flashover of a dielectric coating on the anode and explosive emission of electrons from the anode, as well as in two insulation modes of external-magnetic field and self-magnetic field with either non-closed or closed drift of electrons in the anode-cathode (A-K) gap, respectively. Combined with ion current density measurement, energy density characterization is employed to resolve the spatial distribution of energy density before focusing for exploring the ion beam generation process. Consistent results are obtained on three types of MIDs concerning control of neutralizing electron flows for the space charge of ions where the high ion beam enhancement is determined by effective electron neutralization in the A-K gap, while the HIPIB composition of different ion species downstream from the diode may be considerably affected by the ion beam neutralization during propagation.

Electron spin resonance of an irradiated single crystal of potassium hydrogen maleate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Iwasaki, Machio; Itoh, Koichi

1963-09-15

Electron spin resonance absorptions of x-irradiated single crystals of potassium hydrogen maleate and potassium deuterium maleate were observed. Both compounds gave the same hyperfine structures, although the slightly sharper line widths were observed for the deuterium exchanged compound.

New insights into proton surface mobility processes in PEMFC catalysts using isotopic exchange methods.

PubMed

Ferreira-Aparicio, Paloma

2009-09-01

The surface chemistry and the adsorption/desorption/exchange behavior of a proton-exchange membrane fuel cell catalyst are analyzed as a case study for the development of tailor-made support materials of enhanced performance and stability. By using H2, D2, and CO as probe molecules, the relevance of some surface functional groups of the catalyst support on several diffusion processes taking place during the adsorption is shown. Sulfonic groups associated with the vulcanized carbon black surface have been detected by means of spectroscopic techniques (X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy) and by analysis of the desorbed products during temperature-programmed desorption tests by mass spectrometry. Such hydrophilic species have been observed to favor proton surface mobility and exchange with Pt-adsorbed deuterium even in the presence of adsorbed CO. This behavior is relevant both for the proper characterization of these kinds of catalysts using adsorption probes and for the design of new surface-modified carbon supports, enabling alternative proton-transfer pathways throughout the catalytic layers toward the membrane.

Multi-scale modeling to relate Be surface temperatures, concentrations and molecular sputtering yields

NASA Astrophysics Data System (ADS)

Lasa, Ane; Safi, Elnaz; Nordlund, Kai

2015-11-01

Recent experiments and Molecular Dynamics (MD) simulations show erosion rates of Be exposed to deuterium (D) plasma varying with surface temperature and the correlated D concentration. Little is understood how these three parameters relate for Be surfaces, despite being essential for reliable prediction of impurity transport and plasma facing material lifetime in current (JET) and future (ITER) devices. A multi-scale exercise is presented here to relate Be surface temperatures, concentrations and sputtering yields. Kinetic Monte Carlo (MC) code MMonCa is used to estimate equilibrium D concentrations in Be at different temperatures. Then, mixed Be-D surfaces - that correspond to the KMC profiles - are generated in MD, to calculate Be-D molecular erosion yields due to D irradiation. With this new database implemented in the 3D MC impurity transport code ERO, modeling scenarios studying wall erosion, such as RF-induced enhanced limiter erosion or main wall surface temperature scans run at JET, can be revisited with higher confidence. Work supported by U.S. DOE under Contract DE-AC05-00OR22725.

Development of Approaches for Deuterium Incorporation in Plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Evans, Barbara R

2015-01-01

Soon after the discovery of deuterium, efforts to utilize this stable isotope of hydrogen for labeling of plants began and have proven successful for natural abundance to 20% enrichment. However, isotopic labeling with deuterium (2H) in higher plants at the level of 40% and higher is complicated by both physiological responses, particularly water exchange through transpiration, and inhibitory effects of D2O on germination, rooting, and growth. The highest incorporation of 40 50% had been reported for photoheterotrophic cultivation of the duckweed Lemna. Higher substitution is desirable for certain applications using neutron scattering and nuclear magnetic resonance (NMR) techniques. 1H2H-NMR andmore » mass spectroscopy are standard methods frequently used for determination of location and amount of deuterium substitution. The changes in infrared (IR) absorption observed for H to D substitution in hydroxyl and alkyl groups provide rapid initial evaluation of incorporation. Short-term experiments with cold-tolerant annual grasses can be carried out in enclosed growth containers to evaluate incorporation. Growth in individual chambers under continuous air perfusion with dried sterile-filtered air enables long-term cultivation of multiple plants at different D2O concentrations. Vegetative propagation from cuttings extends capabilities to species with low germination rates. Cultivation in 50% D2O of annual ryegrass and switchgrass following establishment of roots by growth in H2O produces samples with normal morphology and 30 40 % deuterium incorporation in the biomass. Winter grain rye (Secale cereale) was found to efficiently incorporate deuterium by photosynthetic fixation from 50% D2O but did not incorporate deuterated phenylalanine-d8 from the growth medium.« less

[Microbial synthesis of deuterium labelled L-phenylalanine with different levels of isotopic enrichment by facultative methylotrophic bacterium Brevibacterium methylicum with RMP assimilation of carbon].

PubMed

Mosin, O V; Shvets, V I; Skladnev, D A; Ignatov, I

2014-01-01

The preparative microbial synthesis of amino acids labelled with stable isotopes, including deuterium ( 2 H), suitable for biomedical applications by methylotrophic bacteria was studied using L-phenylalanine as example. This amino acid is secreted by Gram-negative aerobic facultative methylotrophic bacteria Brevibacterium methylicum, assimilating methanol via ribulose-5-monophosphate (RMP) cycle of assimilation of carbon, The data on adaptation of L-phenylalanine secreted by methylotrophic bacterium В. methylicum to the maximal concentration of deuterium in the growth medium with 98% 2 Н 2 O and 2% [ 2 Н]methanol, and biosynthesis of deuterium labelled L-phenylalanine With different levels of enrichment are presented. The strain was adapted by means of plating initial cells on firm (2% agarose) minimal growth media with an increasing gradient of 2 Н 2 O concentration from 0; 24.5; 49.0; 73.5 up to 98% 2 Н 2 O followed by subsequent selection of separate colonies stable to the action of 2 Н 2 O. These colonies were capable to produce L-phenylalanine. L-phenylalanine was extracted from growth medium by extraction with isopropanol with the subsequent crystallization in ethanol (output 0.65 g/l). The developed method of microbial synthesis allows to obtain deuterium labelled L-phenylalanine with different levels of isotopic enrichment, depending on concentration of 2 Н 2 O in growth media, from 17% (on growth medium with 24,5% 2 Н 2 O) up to 75% (on growth medium with 98% 2 Н 2 O) of deuterium in the molecule that is confirmed with the data of the electron impact (EI) mass- spectrometry analysis of methyl ethers of N-dimethylamino(naphthalene)-5-sulfochloride (dansyl) phenylalanine in these experimental conditions.

E2C mechanism of elimination reactions. IX. Secondary deuterium isotope effects on rates of bimolecular reactions in alicyclic systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cook, D.

1976-06-11

Secondary ..cap alpha..-deuterium isotope effects on the rates of NBu/sub 4/OAc and NBu/sub 4/Cl promoted bimolecular reactions (E2 and SN2) of cyclohexyl tosylate and cyclohexyl bromide have been studied. The E2 reactions, previously categorized as E2C-like, show ..cap alpha..-deuterium isotope effects in the range 1.14--1.22, while the related SN2 reactions give values in the range 1.05--1.08. The discrepancy in the magnitude of the ..cap alpha..-deuterium isotope effect for the E2 and SN2 processes is consistent with the view that E2C-like reactions use ''looser'' transition states than those used in the concurrent SN2 reactions. While the reported ..cap alpha..-d isotope effectsmore » do not provide positive evidence to support the idea that the base interacts with C/sub ..cap alpha../ in the E2 transition states of the reactions studied, neither do they substantiate claims for dismissal of the concept. A comparison of the secondary ..gamma..-deuterium and ..beta..'-deuterium isotope effects arising in the reaction of cyclohexyl tosylate with NBu/sub 4/OAc in acetone indicates the two isotope effects to be of equivalent magnitude (k/sub ..beta..'-d/k/sub ..gamma..-d/ = 0.98). This observation can only be rationalized for this reaction in terms of a transition state structure in which there is extensive double bond development. It provides compelling evidence against the involvement of any transition state structure which accommodates extensive positive charge development at C/sub ..cap alpha../.« less

Modeling of erosion and deposition patterns on C-W and W-Ta twin limiters exposed to the TEXTOR edge plasmas

NASA Astrophysics Data System (ADS)

Ohya, K.; Tanabe, T.; Rubel, M.; Wada, M.; Ohgo, T.; Hirai, T.; Philipps, V.; Kirschner, A.; Pospieszczyk, A.; Huber, A.; Sergienko, G.; Brezinsek, S.; Noda, N.

2004-08-01

The erosion and deposition patterns on tungsten and tantalum test limiters exposed to the TEXTOR deuterium plasma containing a small amount of C impurity are simulated with the modified EDDY code. At the very top of the W and Ta limiters, there occurs neither erosion nor deposition, but the erosion proceeds slowly along the surface. When approaching the edge, the surface is covered by a thick C layer, which shows a very sharp boundary similar to the observation in surface measurements. In the erosion zone, the re-deposited carbon forms a W (Ta)-C mixed layer with small C concentration. Assumptions for chemical erosion yields of ˜0.01 for W and <0.005 for Ta fit the calculated widths of the deposition zone to the experimentally determined values. Possible reasons for the difference between W and Ta are discussed.

Isotopic Tracers for Delineating Non-Point Source Pollutants in Surface Water

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davisson, M L

2001-03-01

This study tested whether isotope measurements of surface water and dissolved constituents in surface water could be used as tracers of non-point source pollution. Oxygen-18 was used as a water tracer, while carbon-14, carbon-13, and deuterium were tested as tracers of DOC. Carbon-14 and carbon-13 were also used as tracers of dissolved inorganic carbon, and chlorine-36 and uranium isotopes were tested as tracers of other dissolved salts. In addition, large databases of water quality measurements were assembled for the Missouri River at St. Louis and the Sacramento-San Joaquin Delta in California to enhance interpretive results of the isotope measurements. Muchmore » of the water quality data has been under-interpreted and provides a valuable resource to investigative research, for which this report exploits and integrates with the isotope measurements.« less

Hydrogen isotopic substitution of solid methylamine through atomic surface reactions at low temperatures: A potential contribution to the D/H ratio of methylamine in molecular clouds

NASA Astrophysics Data System (ADS)

Oba, Yasuhiro; Chigai, Takeshi; Osamura, Yoshihiro; Watanabe, Naoki; Kouchi, Akira

2014-01-01

We experimentally studied hydrogen (H)-deuterium (D) substitution reactions of solid methylamine (CH3NH2) under astrophysically relevant conditions. We also calculated the potential energy surface for the H-D substitution reactions of methylamine isotopologues using quantum chemical methods. Despite the relatively large energy barrier of more than 18 kJ mol-1, CH3NH2 reacted with D atoms to yield deuterated methylamines at 10 K, suggesting that the H-D substitution reaction proceeds through quantum tunneling. Deuterated methylamines reacted with H atoms as well. On the basis of present results, we propose that methylamine has potential for D enrichment through atomic surface reactions on interstellar grains at very low temperatures in molecular clouds. D enrichment would occur in particular in the methyl group of methylamine.

Tritium Decay Helium-3 Effects in Tungsten

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shimada, M.; Merrill, B. J.

2016-06-01

A critical challenge for long-term operation of ITER and beyond to a Demonstration reactor (DEMO) and future fusion reactor will be the development of plasma-facing components (PFCs) that demonstrate erosion resistance to steady-state/transient heat fluxes and intense neutral/ion particle fluxes under the extreme fusion nuclear environment, while at the same time minimizing in-vessel tritium inventories and permeation fluxes into the PFC’s coolant. Tritium will diffuse in bulk tungsten at elevated temperatures, and can be trapped in radiation-induced trap site (up to 1 at. % T/W) in tungsten [1,2]. Tritium decay into helium-3 may also play a major role in microstructuralmore » evolution (e.g. helium embrittlement) in tungsten due to relatively low helium-4 production (e.g. He/dpa ratio of 0.4-0.7 appm [3]) in tungsten. Tritium-decay helium-3 effect on tungsten is hardly understood, and its database is very limited. Two tungsten samples (99.99 at. % purity from A.L.M.T. Co., Japan) were exposed to high flux (ion flux of 1.0x1022 m-2s-1 and ion fluence of 1.0x1026 m-2) 0.5%T2/D2 plasma at two different temperatures (200, and 500°C) in Tritium Plasma Experiment (TPE) at Idaho National Laboratory. Tritium implanted samples were stored at ambient temperature in air for more than 3 years to investigate tritium decay helium-3 effect in tungsten. The tritium distributions on plasma-exposed was monitored by a tritium imaging plate technique during storage period [4]. Thermal desorption spectroscopy was performed with a ramp rate of 10°C/min up to 900°C to outgas residual deuterium and tritium but keep helium-3 in tungsten. These helium-3 implanted samples were exposed to deuterium plasma in TPE to investigate helium-3 effect on deuterium behavior in tungsten. The results show that tritium surface concentration in 200°C sample decreased to 30 %, but tritium surface concentration in 500°C sample did not alter over the 3 years storage period, indicating possible tritium retention in helium-3 bubble. This paper reports the initial experimental observation of tritium-decay helium-3 in tungsten exposed to deuterium/tritium plasma along with electron microscope analysis and also discusses a Tritium Migration Analysis Program (TMAP) analysis of tritium-decay helium-3 effects on tritium retention in tungsten for DEMO and future fusion reactor. [1] Y. Hatano, et.al., Nucl. Fusion 53 (2013) 073006 [2] M. Shimada, et.al., Nucl. Fusion 55 (2015) 013008 [3] M. Sawan, Fus. Sci. Technol. 66 (2014) 272 [4] T. Otsuka, Fus. Sci. Technol. 60 (2011) 1539 This work was prepared for the U.S. Department of Energy, Office of Fusion Energy Sciences, under the DOE Idaho Field Office contract number DE-AC07-05ID14517.« less

Measurement of deuterium density profiles in the H-mode steep gradient region using charge exchange recombination spectroscopy on DIII-D

DOE PAGES

Haskey, S. R.; Grierson, B. A.; Burrell, K. H.; ...

2016-09-26

Recent completion of a thirty two channel main-ion (deuterium) charge exchange recombination spectroscopy (CER) diagnostic on the DIII-D tokamak enables detailed comparisons between impurity and main-ion temperature, density, and toroidal rotation. In a H-mode DIII-D discharge, these new measurement capabilities are used to provide the deuterium density profile, demonstrate the importance of profile alignment between Thomson scattering and CER diagnostics, and aid in determining the electron temperature at the separatrix. Sixteen sightlines cover the core of the plasma and another sixteen are densely packed towards the plasma edge, providing high resolution measurements across the pedestal and steep gradient region inmore » H-mode plasmas. Extracting useful physical quantities such as deuterium density is challenging due to multiple photoemission processes. Finally, these challenges are overcome using a detailed fitting model and by forward modeling the photoemission using the FIDASIM code, which implements a comprehensive collisional radiative model. Published by AIP Publishing.« less

First-principles simulations of shock front propagation in liquid deuterium

NASA Astrophysics Data System (ADS)

Gygi, Francois; Galli, Giulia

2001-03-01

We present large-scale first-principles molecular dynamics simulations of the formation and propagation of a shock front in liquid deuterium. Molecular deuterium was subjected to supersonic impacts at velocities ranging from 10 to 30 km/s. We used Density Functional Theory in the local density approximation, and simulation cells containing 1320 deuterium atoms. The formation of a shock front was observed and its velocity was measured and compared with the results of laser-driven shock experiments [1]. The pressure and density in the compressed fluid were also computed directly from statistical averages in appropriate regions of the simulation cell, and compared with previous first-principles calculations performed at equilibrium [2]. Details of the electronic structure at the shock front, and their influence on the properties of the compressed fluid will be discussed. [1] J.W.Collins et al. Science 281, 1178 (1998). [2] G.Galli, R.Q.Hood, A.U.Hazi and F.Gygi, Phys.Rev. B61, 909 (2000).

The deuterium depth profile in neutron-irradiated tungsten exposed to plasma

NASA Astrophysics Data System (ADS)

Shimada, Masashi; Cao, G.; Hatano, Y.; Oda, T.; Oya, Y.; Hara, M.; Calderoni, P.

2011-12-01

Tungsten samples (99.99% purity from A.L.M.T. Corp., 6 mm in diameter, 0.2 mm in thickness) were irradiated by high-flux neutrons at 50 °C to 0.025 dpa in the High Flux Isotope Reactor at Oak Ridge National Laboratory. Subsequently, the neutron-irradiated tungsten samples were exposed to high-flux deuterium plasmas (ion flux: 1021-1022 m-2 s-1, ion fluence: 1025-1026 m-2) in the Tritium Plasma Experiment at Idaho National Laboratory. This paper reports the results of deuterium depth profiling in neutron-irradiated tungsten exposed to plasmas at 100, 200 and 500 °C via nuclear reaction analysis (NRA). The NRA measurements show that a significant amount of deuterium (>0.1 at.% D/W) remains trapped in the bulk material (up to 5 μm) at 500 °C. Tritium Migration Analysis Program simulation results using the NRA profiles indicate that different trapping mechanisms exist for neutron-irradiated and unirradiated tungsten.

Deuterium enrichment of polycyclic aromatic hydrocarbons by photochemically induced exchange with deuterium-rich cosmic ices

NASA Technical Reports Server (NTRS)

Sandford, S. A.; Bernstein, M. P.; Allamandola, L. J.; Gillette, J. S.; Zare, R. N.

2000-01-01

The polycyclic aromatic hydrocarbon (PAH) coronene (C24H12) frozen in D2O ice in a ratio of less than 1 part in 500 rapidly exchanges its hydrogen atoms with the deuterium in the ice at interstellar temperatures and pressures when exposed to ultraviolet radiation. Exchange occurs via three different chemical processes: D atom addition, D atom exchange at oxidized edge sites, and D atom exchange at aromatic edge sites. Observed exchange rates for coronene (C24H12)-D2O and d12-coronene (C24D12)-H2O isotopic substitution experiments show that PAHs in interstellar ices could easily attain the D/H levels observed in meteorites. These results may have important consequences for the abundance of deuterium observed in aromatic materials in the interstellar medium and in meteorites. These exchange mechanisms produce deuteration in characteristic molecular locations on the PAHs that may distinguish them from previously postulated processes for D enrichment of PAHs.

Determination of diffusion coefficients of hydrogen and deuterium in Zr-2.5%Nb pressure tube material using hot vacuum extraction-quadrupole mass spectrometry

NASA Astrophysics Data System (ADS)

Shrivastava, Komal Chandra; Kulkarni, A. S.; Ramanjaneyulu, P. S.; Sunil, Saurav; Saxena, M. K.; Singh, R. N.; Tomar, B. S.; Ramakumar, K. L.

2015-06-01

The diffusion coefficients of hydrogen and deuterium in Zr-2.5%Nb alloy were measured in the temperature range 523 to 673 K, employing hot vacuum extraction-quadrupole mass spectrometry (HVE-QMS). One end of the Zr-2.5%Nb alloy specimens was charged electrolytically with the desired hydrogen isotope. After annealing at different temperatures for a predetermined time, the specimens were cut into thin slices, which were analyzed for their H2/D2 content using the HVE-QMS technique. The depth profile data were fitted into the equation representing the solution of Fick's second law of diffusion. The activation energy of hydrogen/deuterium diffusion was obtained from the Arrhenius relation between the diffusion coefficient and temperature. The temperature dependent diffusion coefficient can be represented as DH = 1.41 × 10-7 exp(-36,000/RT) and DD = 6.16 × 10-8 exp(-35,262/RT) for hydrogen and deuterium, respectively.

Measurement of deuterium density profiles in the H-mode steep gradient region using charge exchange recombination spectroscopy on DIII-D.

PubMed

Haskey, S R; Grierson, B A; Burrell, K H; Chrystal, C; Groebner, R J; Kaplan, D H; Pablant, N A; Stagner, L

2016-11-01

Recent completion of a thirty two channel main-ion (deuterium) charge exchange recombination spectroscopy (CER) diagnostic on the DIII-D tokamak [J. L. Luxon, Nucl. Fusion 42, 614 (2002)] enables detailed comparisons between impurity and main-ion temperature, density, and toroidal rotation. In a H-mode DIII-D discharge, these new measurement capabilities are used to provide the deuterium density profile, demonstrate the importance of profile alignment between Thomson scattering and CER diagnostics, and aid in determining the electron temperature at the separatrix. Sixteen sightlines cover the core of the plasma and another sixteen are densely packed towards the plasma edge, providing high resolution measurements across the pedestal and steep gradient region in H-mode plasmas. Extracting useful physical quantities such as deuterium density is challenging due to multiple photoemission processes. These challenges are overcome using a detailed fitting model and by forward modeling the photoemission using the FIDASIM code, which implements a comprehensive collisional radiative model.

Refinement of the experimental dynamic structure factor for liquid para-hydrogen and ortho-deuterium using semi-classical quantum simulation.

PubMed

Smith, Kyle K G; Poulsen, Jens Aage; Cunsolo, A; Rossky, Peter J

2014-01-21

The dynamic structure factor of liquid para-hydrogen and ortho-deuterium in corresponding thermodynamic states (T = 20.0 K, n = 21.24 nm(-3)) and (T = 23.0 K, n = 24.61 nm(-3)), respectively, has been computed by both the Feynman-Kleinert linearized path-integral (FK-LPI) and Ring-Polymer Molecular Dynamics (RPMD) methods and compared with Inelastic X Ray Scattering spectra. The combined use of computational and experimental methods enabled us to reduce experimental uncertainties in the determination of the true sample spectrum. Furthermore, the refined experimental spectrum of para-hydrogen and ortho-deuterium is consistently reproduced by both FK-LPI and RPMD results at momentum transfers lower than 12.8 nm(-1). At larger momentum transfers the FK-LPI results agree with experiment much better for ortho-deuterium than for para-hydrogen. More specifically we found that for k ∼ 20.0 nm(-1) para-hydrogen provides a test case for improved approximations to quantum dynamics.

Measurement of deuterium density profiles in the H-mode steep gradient region using charge exchange recombination spectroscopy on DIII-D

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haskey, S. R.; Grierson, B. A.; Burrell, K. H.

Recent completion of a thirty two channel main-ion (deuterium) charge exchange recombination spectroscopy (CER) diagnostic on the DIII-D tokamak enables detailed comparisons between impurity and main-ion temperature, density, and toroidal rotation. In a H-mode DIII-D discharge, these new measurement capabilities are used to provide the deuterium density profile, demonstrate the importance of profile alignment between Thomson scattering and CER diagnostics, and aid in determining the electron temperature at the separatrix. Sixteen sightlines cover the core of the plasma and another sixteen are densely packed towards the plasma edge, providing high resolution measurements across the pedestal and steep gradient region inmore » H-mode plasmas. Extracting useful physical quantities such as deuterium density is challenging due to multiple photoemission processes. Finally, these challenges are overcome using a detailed fitting model and by forward modeling the photoemission using the FIDASIM code, which implements a comprehensive collisional radiative model. Published by AIP Publishing.« less

Measurement of deuterium density profiles in the H-mode steep gradient region using charge exchange recombination spectroscopy on DIII-D

NASA Astrophysics Data System (ADS)

Haskey, S. R.; Grierson, B. A.; Burrell, K. H.; Chrystal, C.; Groebner, R. J.; Kaplan, D. H.; Pablant, N. A.; Stagner, L.

2016-11-01

Recent completion of a thirty two channel main-ion (deuterium) charge exchange recombination spectroscopy (CER) diagnostic on the DIII-D tokamak [J. L. Luxon, Nucl. Fusion 42, 614 (2002)] enables detailed comparisons between impurity and main-ion temperature, density, and toroidal rotation. In a H-mode DIII-D discharge, these new measurement capabilities are used to provide the deuterium density profile, demonstrate the importance of profile alignment between Thomson scattering and CER diagnostics, and aid in determining the electron temperature at the separatrix. Sixteen sightlines cover the core of the plasma and another sixteen are densely packed towards the plasma edge, providing high resolution measurements across the pedestal and steep gradient region in H-mode plasmas. Extracting useful physical quantities such as deuterium density is challenging due to multiple photoemission processes. These challenges are overcome using a detailed fitting model and by forward modeling the photoemission using the FIDASIM code, which implements a comprehensive collisional radiative model.

DNA Interactions Probed by Hydrogen-Deuterium Exchange (HDX) Fourier Transform Ion Cyclotron Resonance Mass Spectrometry Confirm External Binding Sites on the Minichromosomal Maintenance (MCM) Helicase*

PubMed Central

Graham, Brian W.; Tao, Yeqing; Dodge, Katie L.; Thaxton, Carly T.; Olaso, Danae; Young, Nicolas L.; Marshall, Alan G.

2016-01-01

The archaeal minichromosomal maintenance (MCM) helicase from Sulfolobus solfataricus (SsoMCM) is a model for understanding structural and mechanistic aspects of DNA unwinding. Although interactions of the encircled DNA strand within the central channel provide an accepted mode for translocation, interactions with the excluded strand on the exterior surface have mostly been ignored with regard to DNA unwinding. We have previously proposed an extension of the traditional steric exclusion model of unwinding to also include significant contributions with the excluded strand during unwinding, termed steric exclusion and wrapping (SEW). The SEW model hypothesizes that the displaced single strand tracks along paths on the exterior surface of hexameric helicases to protect single-stranded DNA (ssDNA) and stabilize the complex in a forward unwinding mode. Using hydrogen/deuterium exchange monitored by Fourier transform ion cyclotron resonance MS, we have probed the binding sites for ssDNA, using multiple substrates targeting both the encircled and excluded strand interactions. In each experiment, we have obtained >98.7% sequence coverage of SsoMCM from >650 peptides (5–30 residues in length) and are able to identify interacting residues on both the interior and exterior of SsoMCM. Based on identified contacts, positively charged residues within the external waist region were mutated and shown to generally lower DNA unwinding without negatively affecting the ATP hydrolysis. The combined data globally identify binding sites for ssDNA during SsoMCM unwinding as well as validating the importance of the SEW model for hexameric helicase unwinding. PMID:27044751

Evidence From Hydrogen Isotopes in Meteorites for a Martian Permafrost

NASA Technical Reports Server (NTRS)

Usui, T.; Alexander, C. M. O'D.; Wang, J.; Simon, J. I.; Jones, J. H.

2014-01-01

Fluvial landforms on Mars suggest that it was once warm enough to maintain persistent liquid water on its surface. The transition to the present cold and dry Mars is closely linked to the history of surface water, yet the evolution of surficial water is poorly constrained. We have investigated the evolution of surface water/ ice and its interaction with the atmosphere by measurements of hydrogen isotope ratios (D/H: deuterium/ hydrogen) of martian meteorites. Hydrogen is a major component of water (H2O) and its isotopes fractionate significantly during hydrological cycling between the atmosphere, surface waters, ground ice, and polar cap ice. Based on in situ ion microprobe analyses of three geochemically different shergottites, we reported that there is a water/ice reservoir with an intermediate D/H ratio (delta D = 1,000?2500 %) on Mars. Here we present the possibility that this water/ice reservoir represents a ground-ice/permafrost that has existed relatively intact over geologic time.

Outgassing Measurements for Three Materials, Combined with Vacuum Ultraviolet Radiation Illumination of the Volatile Condensable Materials

NASA Technical Reports Server (NTRS)

Albyn, Keith

2005-01-01

The photolysis of three organic materials, by vacuum ultraviolet (VUV) radiation, has been quantified using 15-MHz temperature-controlled quartz microbalances (TQCM's). The rate at which molecular species, released from the individual samples, condensed on two TQCM s was measured for periods of up to 139.9-hours. The individual samples were heated in an effusion cell and the emitted molecular species collected on a pair of TQCM's which were maintained at -40 degrees Celsius. At several points during the deposition measurement, the deposition surface of one TQCM was illuminated by a 30 Watt deuterium lamp, and the loss of material from that surface was observed. V W illumination of the TQCM, concurrent with condensation, reduced the rate that material was lost from the deposition surface. These measurements present a contrasting picture of molecular deposition, in the presence of VUV, to that presented by other investigators who observed an enhanced rate of molecular deposition, when the deposition surface was illuminated by VUV.

Spectral irradiance standard for the ultraviolet - The deuterium lamp

NASA Technical Reports Server (NTRS)

Saunders, R. D.; Ott, W. R.; Bridges, J. M.

1978-01-01

A set of deuterium lamps is calibrated as spectral irradiance standards in the 200-350-nm spectral region utilizing both a high accuracy tungsten spectral irradiance standard and a newly developed argon mini-arc spectral radiance standard. The method which enables a transfer from a spectral radiance to a spectral irradiance standard is described. The following characteristics of the deuterium lamp irradiance standard are determined: sensitivity to alignment; dependence on input power and solid angle; reproducibility; and stability. The absolute spectral radiance is also measured in the 167-330-nm region. Based upon these measurements, values of the spectral irradiance below 200 nm are obtained through extrapolation.

Estimation of d- 2 H Breakup Neutron Energy Distributions From d- 3 He

DOE PAGES

Hoop, B.; Grimes, S. M.; Drosg, M.

2017-06-19

A method is described to estimate deuteron-on-deuteron breakup neutron distributions at 0° using deuterium bombardment of 3He. Break-up neutron distributions are modeled with the product of a Fermi-Dirac distribution and a cumulative logistic distribution function. Four measured break-up neutron distributions from 6.15- to 12.0-MeV deuterons on 3He are compared with thirteen measured distributions from 6.83- to 11.03-MeV deuterons on deuterium. Model pararmeters that describe d -3He neutron distributions are used to estimate neutron distributions from 6- to 12-MeV deuterons on deuterium.

URBAN STORMWATER TRACING WITH THE NATURALLY OCCURRING DEUTERIUM ISOTOPE

EPA Science Inventory

Measurements of the naturally-occurring deuterium isotope assist the tracing of water components during wet-weather flows in an urban watershed. A transect of installations in the vadose and saturated zones was completed in the vicinity of a small stream and storm sewer. High-r...

Ordered ground states of metallic hydrogen and deuterium

NASA Technical Reports Server (NTRS)

Ashcroft, N. W.

1981-01-01

The physical attributes of some of the more physically distinct ordered states of metallic hydrogen and metallic deuterium at T = 0 and nearby are discussed. The likelihood of superconductivity in both is considered with respect to the usual coupling via the density fluctuations of the ions.

METHOD OF OPERATING A NEUTRONIC REACTOR

DOEpatents

Turkevich, A.

1963-01-22

This patent relates to one step in a method of operating a neutronic reactor consisting of a slurry of fissionable material in heavy water. Deuterium gas is passed through the slurry to sweep gaseous fission products therefrom and the deuterium is then separated from the gaseous fission products. (AEC)

Qualitative and quantitative analysis of mixtures of compounds containing both hydrogen and deuterium

NASA Technical Reports Server (NTRS)

Crespi, H. L.; Harkness, L.; Katz, J. J.; Norman, G.; Saur, W.

1969-01-01

Method allows qualitative and quantitative analysis of mixtures of partially deuterated compounds. Nuclear magnetic resonance spectroscopy determines location and amount of deuterium in organic compounds but not fully deuterated compounds. Mass spectroscopy can detect fully deuterated species but not the location.

The nature of abrupt climate change during the last glacial period from detailed isotopic records from the NGRIP ice core

NASA Astrophysics Data System (ADS)

Popp, T. J.; Svensson, A.; Steffensen, J. P.; Johnsen, S. J.; White, J. W. C.

2009-04-01

Isotopic and chemical impurity records from Greenland ice cores with sub-annual resolution across three fast climate transitions of the last deglacial termination reveal complex patterns of environmental change for the onset of Greenland Interstadial 1 (GI-1 or Bølling), the onset of Greenland Stadial 1 (GS-1 or Younger Dryas), and the onset of the Holocene. In the NGRIP ice core each of these transitions is initiated by a 1-3 year mode shift in deuterium excess, which is a proxy for the Greenland precipitation moisture source. These mode shifts in deuterium excess are decoupled in time from the isotopic (deuterium and oxygen-18) transitions from which they are derived. In general the abrupt isotopic transitions follow the corresponding deuterium excess shifts and span decades rather than years. Similar data from GISP2 confirms the clear deuterium excess mode shifts for transitions from cold states to warm states; however the abrupt deuterium excess transition at the onset of GS-1 is not expressed in a similar way at GISP2. Ironically, it appears that this cooling at the beginning of the Younger Dryas, for which we have theories of the triggering event, is less clearly recorded than warming events, the triggering of which is still poorly understood. Along with other available paleo-data, these results indicate that the sum of an abrupt climate change is composed of multiple responses from different parts of the climate system. These responses can be separated by as little as a single year to a few decades and the collection of these responses result in a variety of abrupt transitions giving each a unique anatomy. Here we expand this type of analysis with new isotope, deuterium excess, and accumulation rate time series from NGRIP across the abrupt transitions associated with several interstadial events of the Last Glacial period (Dansgaard-Oeschger events). Indeed the temporal phasing of deuterium excess and the isotopic content of the ice can vary from one event to the next and emerging patterns may depend on the conditions associated with specific events such as Heinrich Events and ice volume boundary conditions. Together with modeling and chemical impurity data, these patterns will provide clues to the timing and origin of ocean and atmospheric changes that comprise an abrupt climate change. The emerging picture indicates that abrupt climate changes have both a temporal and geographic anatomy that can change from one event to the next in how they are recorded across Greenland.

Role of deuterium desorption kinetics on the thermionic emission properties of polycrystalline diamond films with respect to kinetic isotope effects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Paxton, W. F., E-mail: william.f.paxton@vanderbilt.edu; Howell, M.; Kang, W. P.

2014-06-21

The desorption kinetics of deuterium from polycrystalline chemical vapor deposited diamond films were characterized by monitoring the isothermal thermionic emission current behavior. The reaction was observed to follow a first-order trend as evidenced by the decay rate of the thermionic emission current over time which is in agreement with previously reported studies. However, an Arrhenius plot of the reaction rates at each tested temperature did not exhibit the typical linear behavior which appears to contradict past observations of the hydrogen (or deuterium) desorption reaction from diamond. This observed deviation from linearity, specifically at lower temperatures, has been attributed to non-classicalmore » processes. Though no known previous studies reported similar deviations, a reanalysis of the data obtained in the present study was performed to account for tunneling which appeared to add merit to this hypothesis. Additional investigations were performed by reevaluating previously reported data involving the desorption of hydrogen (as opposed to deuterium) from diamond which further indicated this reaction to be dominated by tunneling at the temperatures tested in this study (<775 °C). An activation energy of 3.19 eV and a pre-exponential constant of 2.3 × 10{sup 12} s{sup −1} were determined for the desorption reaction of deuterium from diamond which is in agreement with previously reported studies.« less

Acceleration of Hydrogen Ions up to 30 MeV and Generation of 3 × 1012 Neutrons in Megaampere Deuterium Gas-Puff Z-Pinch

NASA Astrophysics Data System (ADS)

Klir, D.; Cikhardt, J.; Kravarik, J.; Kubes, P.; Rezac, K.; Sila, O.; Shishlov, A.; Cherdizov, R.; Fursov, F.; Kokshenev, V.; Kovalchuk, B.; Kurmaev, N.; Labetsky, A.; Ratakhin, N.; Orcikova, H.; Turek, K.

2013-10-01

Fusion neutrons were produced with a deuterium gas-puff z-pinch on the GIT-12 generator at the Institute of High Current Electronics in Tomsk. The peak neutron yield from DD reactions reached Yn = (2 . 9 +/- 0 . 3) ×1012 at 100 μg/cm linear mass density of deuterium, 700 ns implosion time and 2.7 MA current. Such a neutron yield means that the scaling law of deuterium z-pinches Yn ~I4 was extended to 3 MA currents. The further increase of neutron yields up to (3 . 7 +/- 0 . 4) ×1012 was achieved by placing a deuterated polyethylene catcher onto the axis. Maximum neutron energies of 15 and 22 MeV were observed by radial and axial nToF detectors, respectively. A stack of CR-39 track detectors showed up to 40 MeV deuterons (or 30 MeV protons) on the z-pinch axis. Since the energy input into plasmas was 70 kJ, the number of DD neutrons per one joule of stored plasma energy exceeded the value of 5 ×107 . This value implies that deuterium gas-puff z-pinches belong to the most efficient plasma-based sources of DD neutrons. This work was partially supported by the GACR grant No. P205/12/0454 and by the RFBR research project No. 13-08-00479-a.

Reexamination of D retention behavior in He ion irradiated RAFMs

NASA Astrophysics Data System (ADS)

Zhou, H.-S.; Xu, Y.-P.; Liu, H.-D.; Lyu, Y.-M.; Liu, F.; Cao, X.-Z.; Wang, B.-Y.; Zhu, T.; Ding, F.; Luo, G.-N.

2018-05-01

Helium (He) effects on deuterium (D) retention in reduced activation ferritic/martensitic steel (RAFMs) have been studied by high-energy He ion pre-injection and following D plasma exposure. He-damaged layers at the surface and inside the material bulk are induced by 3.5 MeV He ion bombardments with and without energy degrader, respectively. Iron (Fe) ion pre-irradiation is performed as a comparison so that He effects are clearly distinguished. It has been found that He injected into the bulk of RAFMs can suppress D retention whereas D behavior is not significantly affected by the damages from high-energy Fe ion. When the damage layers are shifted to the near surface, D retention is enhanced by both of He and Fe pre-irradiation.

Implosion spectroscopy in Rugby hohlraums on OMEGA

NASA Astrophysics Data System (ADS)

Philippe, Franck; Tassin, Veronique; Bitaud, Laurent; Seytor, Patricia; Reverdin, Charles

2014-10-01

The rugby hohlraum concept has been validated in previous experiments on the OMEGA laser facility. This new hohlraum type can now be used as a well-characterized experimental platform to study indirect drive implosion, at higher radiation temperatures than would be feasible at this scale with classical cylindrical hohlraums. Recent experiments have focused on the late stages of implosion and hotspot behavior. The capsules included both a thin buried Titanium tracer layer, 0-3 microns from the inner surface, Argon dopant in the deuterium gas fuel and Germanium doped CH shells, providing a variety of spectral signatures of the plasma conditions in different parts of the target. X-ray spectroscopy and imaging were used to study compression, Rayleigh-Taylor instabilities growth at the inner surface and mix between the shell and gas.

Evidence for primordial water in Earth's deep mantle.

PubMed

Hallis, Lydia J; Huss, Gary R; Nagashima, Kazuhide; Taylor, G Jeffrey; Halldórsson, Sæmundur A; Hilton, David R; Mottl, Michael J; Meech, Karen J

2015-11-13

The hydrogen-isotope [deuterium/hydrogen (D/H)] ratio of Earth can be used to constrain the origin of its water. However, the most accessible reservoir, Earth's oceans, may no longer represent the original (primordial) D/H ratio, owing to changes caused by water cycling between the surface and the interior. Thus, a reservoir completely isolated from surface processes is required to define Earth's original D/H signature. Here we present data for Baffin Island and Icelandic lavas, which suggest that the deep mantle has a low D/H ratio (δD more negative than -218 per mil). Such strongly negative values indicate the existence of a component within Earth's interior that inherited its D/H ratio directly from the protosolar nebula. Copyright © 2015, American Association for the Advancement of Science.

The deuterium puzzle in the symmetric universe

NASA Technical Reports Server (NTRS)

Leroy, B.; Nicolle, J. P.; Schatzman, E.

1973-01-01

An attempt was made to use deuterium abundance in the symmetric universe to prove that no nucleosynthesis takes place during annihilation and therefore neutrons were loss before nucleosynthesis. Data cover nucleosynthesis during the radiative era, cross section estimates, maximum abundance of He-4 at the end of nucleosynthesis area, and loss rate.

76 FR 52994 - Application for a License To Export Heavy Water

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-24

... NUCLEAR REGULATORY COMMISSION Application for a License To Export Heavy Water Pursuant to 10 CFR... (liters). producing an active water). pharmaceutical ingredient known as CTP-499, which incorporates heavy water as the source of deuterium to achieve the hydrogen-deuterium exchange. November 30, 2010 December...

Alkyl group substitution by oxime-bound palladium(II) (the Shaw reaction): Alkly group selectivity and deuterium isotope effects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wells, A.P.; Kitching, W.

1992-08-01

This report provides information regarding the selectivity of alkyl groups and the nature of the transition state for C-H palladation by oxime-bound palladium(II) (the Shaw reaction). The kinetic deuterium isotope effects are also presented. 21 refs.

INVESTIGATION OF ARSINE-GENERATING REACTIONS USING DEUTERIUM-LABELED REAGENTS AND MASS SPECTROMETRY

EPA Science Inventory

Mass spectrometry was used to detect transfer of deuterium from labeled reagents to arsines following hydride-generation reactions. The arsine gases liberated from the reactions of arsenite, arsenate, methylarsonic acid, and dimethylarsinic acid with HC1 and NaBD4 in H2O, or with...

The ratio of the nucleon structure functions F2N for iron and deuterium

NASA Astrophysics Data System (ADS)

Aubert, J. J.; Bassompierre, G.; Becks, K. H.; Best, C.; Böhm, E.; de Bouard, X.; Brasse, F. W.; Broll, C.; Brown, S.; Carr, J.; Clifft, R. W.; Cobb, J. H.; Coignet, G.; Combley, F.; Court, G. R.; D'Agostini, G.; Dau, W. D.; Davies, J. K.; Déclais, Y.; Dobinson, R. W.; Dosselli, U.; Drees, J.; Edwards, A. W.; Edwards, M.; Favier, J.; Ferrero, M. I.; Flauger, W.; Gabathuler, E.; Gamet, R.; Gayler, J.; Gerhardt, V.; Gössling, C.; Haas, J.; Hamacher, K.; Hayman, P.; Henckes, M.; Korbel, V.; Landgraf, U.; Leenen, M.; Maire, M.; Minssieux, H.; Mohr, W.; Montgomery, H. E.; Moser, K.; Mount, R. P.; Norton, P. R.; McNicholas, J.; Osborne, A. M.; Payre, P.; Peroni, C.; Pessard, H.; Pietrzyk, U.; Rith, K.; Schneegans, M.; Sloan, T.; Stier, H. E.; Stockhausen, W.; Thénard, J. M.; Thompson, J. C.; Urban, L.; Villers, M.; Wahlen, H.; Whalley, M.; Williams, D.; Williams, W. S. C.; Williamson, J.; Wimpenny, S. J.

1983-03-01

Using the data on deep inelastic muon scattering on iron and deuterium the ratio of the nucleon structure functions F2N(Fe)/F2N(D) is presented. The observed x-dependence of this ratio is in disagreement with existing theoretical predictions.

Volcanic ash impacts on critical infrastructure

NASA Astrophysics Data System (ADS)

Wilson, Thomas M.; Stewart, Carol; Sword-Daniels, Victoria; Leonard, Graham S.; Johnston, David M.; Cole, Jim W.; Wardman, Johnny; Wilson, Grant; Barnard, Scott T.

2012-01-01

Volcanic eruptions can produce a wide range of hazards. Although phenomena such as pyroclastic flows and surges, sector collapses, lahars and ballistic blocks are the most destructive and dangerous, volcanic ash is by far the most widely distributed eruption product. Although ash falls rarely endanger human life directly, threats to public health and disruption to critical infrastructure services, aviation and primary production can lead to significant societal impacts. Even relatively small eruptions can cause widespread disruption, damage and economic loss. Volcanic eruptions are, in general, infrequent and somewhat exotic occurrences, and consequently in many parts of the world, the management of critical infrastructure during volcanic crises can be improved with greater knowledge of the likely impacts. This article presents an overview of volcanic ash impacts on critical infrastructure, other than aviation and fuel supply, illustrated by findings from impact assessment reconnaissance trips carried out to a wide range of locations worldwide by our international research group and local collaborators. ‘Critical infrastructure’ includes those assets, frequently taken for granted, which are essential for the functioning of a society and economy. Electricity networks are very vulnerable to disruption from volcanic ash falls. This is particularly the case when fine ash is erupted because it has a greater tendency to adhere to line and substation insulators, where it can cause flashover (unintended electrical discharge) which can in turn cause widespread and disruptive outages. Weather conditions are a major determinant of flashover risk. Dry ash is not conductive, and heavy rain will wash ash from insulators, but light rain/mist will mobilise readily-soluble salts on the surface of the ash grains and lower the ash layer’s resistivity. Wet ash is also heavier than dry ash, increasing the risk of line breakage or tower/pole collapse. Particular issues for water supply managers include: monitoring turbidity levels in raw water intakes, and if necessary increasing chlorination to compensate for higher turbidity; managing water demand; and communicating monitoring results with the public to allay fears of contamination. Ash can cause major damage to wastewater disposal systems. Ash deposited onto impervious surfaces such as roads and car parks is very easily washed into storm drains, where it can form intractable masses and lead to long-term flooding problems. It can also enter wastewater treatment plants (WWTPs), both through sewer lines and by direct fallout. Damage to modern WWTPs can run into millions of dollars. Ash falls reduce visibility creating hazards for ground transportation. Dry ash is also readily remobilised by vehicle traffic and wind, and dry and wet ash deposits will reduce traction on paved surfaces, including airport runways. Ash cleanup from road and airports is commonly necessary, but the large volumes make it logistically challenging. Vehicles are vulnerable to ash; it will clog filters and brake systems and abrade moving parts within engines. Lastly, modern telecommunications networks appear to be relatively resilient to volcanic ash fall. Signal attenuation and interference during ash falls has not been reported in eruptions over the past 20 years, with the exception of interference from ash plume-generated lightning. However, some telecommunications equipment is vulnerable to airborne ash, in particular heating, ventilation and air-conditioning (HVAC) systems which may become blocked from ash ingestion leading to overheating. This summary of volcanic ash impacts on critical infrastructure provides insight into the relative vulnerability of infrastructure under a range of different ashfall scenarios. Identifying and quantifying these impacts is an essential step in building resilience within these critical systems. We have attempted to consider interdependencies between sectors in a holistic way using systems thinking. As modern society becomes increasingly complex and interdependent this approach is likely to become increasingly necessary.

Techniques for determining total body water using deuterium oxide

NASA Technical Reports Server (NTRS)

Bishop, Phillip A.

1990-01-01

The measurement of total body water (TBW) is fundamental to the study of body fluid changes consequent to microgravity exposure or treatment with microgravity countermeasures. Often, the use of radioactive isotopes is prohibited for safety or other reasons. It was selected and implemented for use by some Johnson Space Center (JCS) laboratories, which permitted serial measurements over a 14 day period which was accurate enough to serve as a criterion method for validating new techniques. These requirements resulted in the selection of deuterium oxide dilution as the method of choice for TBW measurement. The development of this technique at JSC is reviewed. The recommended dosage, body fluid sampling techniques, and deuterium assay options are described.

Modeling of hydrogen/deuterium dynamics and heat generation on palladium nanoparticles for hydrogen storage and solid-state nuclear fusion.

PubMed

Tanabe, Katsuaki

2016-01-01

We modeled the dynamics of hydrogen and deuterium adsorbed on palladium nanoparticles including the heat generation induced by the chemical adsorption and desorption, as well as palladium-catalyzed reactions. Our calculations based on the proposed model reproduce the experimental time-evolution of pressure and temperature with a single set of fitting parameters for hydrogen and deuterium injection. The model we generated with a highly generalized set of formulations can be applied for any combination of a gas species and a catalytic adsorbent/absorbent. Our model can be used as a basis for future research into hydrogen storage and solid-state nuclear fusion technologies.

Streaked x-ray backlighting with twin-slit imager for study of density profile and trajectory of low-density foam target filled with deuterium liquid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shiraga, H.; Mahigashi, N.; Yamada, T.

2008-10-15

Low-density plastic foam filled with liquid deuterium is one of the candidates for inertial fusion target. Density profile and trajectory of 527 nm laser-irradiated planer foam-deuterium target in the acceleration phase were observed with streaked side-on x-ray backlighting. An x-ray imager employing twin slits coupled to an x-ray streak camera was used to simultaneously observe three images of the target: self-emission from the target, x-ray backlighter profile, and the backlit target. The experimentally obtained density profile and trajectory were in good agreement with predictions by one-dimensional hydrodynamic simulation code ILESTA-1D.

Deuterium Abundance in the Local Interstellar Medium

NASA Technical Reports Server (NTRS)

Ferlet, R.; Gry, C.; Vidal-Madjar, A.

1984-01-01

The present situation of deuterium abundance evaluation in interstellar space is discussed, and it is shown that it should be or = .00001 by studying in more detail lambda the Sco line of sight and by observing two NaI interstellar components toward that star, it can be shown that the D/H evaluation made toward lambda Sco is in fact related to the local interstellar medium (less than 10 pc from the Sun). Because this evaluation is also or = .00001 it is in striking contrast with the one made toward alpha Aur (D/H or = .000018 confirming the fact that the deuterium abundance in the local interstellar medium varies by at least a factor of two over few parsecs.

Microwave-assisted deuterium exchange: the convenient preparation of isotopically labelled analogues for stable isotope dilution analysis of volatile wine phenols.

PubMed

Crump, Anna M; Sefton, Mark A; Wilkinson, Kerry L

2014-11-01

This study reports the convenient, low cost, one-step synthesis of labelled analogues of six volatile phenols, guaiacol, 4-methylguaiacol, 4-ethylguaiacol, 4-ethylphenol, eugenol and vanillin, using microwave-assisted deuterium exchange, for use as internal standards for stable isotope dilution analysis. The current method improves on previous strategies in that it enables incorporation of deuterium atoms on the aromatic ring, thereby ensuring retention of the isotope label during mass spectrometry fragmentation. When used as standards for SIDA, these labelled volatile phenols will improve the accuracy and reproducibility of quantitative food and beverage analysis. Copyright © 2014 Elsevier Ltd. All rights reserved.

A Gamma Polarimeter for Neutron Polarization Measurement in a Liquid Deuterium Target for Parity Violation in Polarized Neutron Capture on Deuterium.

PubMed

Komives, A; Sint, A K; Bowers, M; Snow, M

2005-01-01

A measurement of the parity-violating gamma asymmetry in n-D capture would yield information on N-N parity violation independent of the n-p system. Since cold neutrons will depolarize in a liquid deuterium target in which the scattering cross section is much larger than the absorption cross section, it will be necessary to quantify the loss of polarization before capture. One way to do this is to use the large circular polarization of the gamma from n-D capture and analyze the circular polarization of the gamma in a gamma polarimeter. We describe the design of this polarimeter.

High-resolution spectroscopy of the 1S-2S transition of atomic hydrogen and deuterium

NASA Astrophysics Data System (ADS)

Schmidt-Kaler, F.; Leibfried, D.; Seel, S.; Zimmermann, C.; König, W.; Weitz, M.; Hänsch, T. W.

1995-04-01

Two-photon spectroscopy of the hydrogen 1S-2S transition in a cold atomic beam has reached a resolution Δν/ν of 1 part in 1011 in hydrogen and 7 parts in 1012 in deuterium. The hydrogen and deuterium 1S-2S transition frequencies have been determined with a precision of 1 part in 1011. This leads to an accurate value for the Rydberg constant, while the 1S Lamb shift and the isotope shift are determined with order of magnitude improvements over previous measurements. We describe in detail the 1S-2S spectrometer, calculate the line shape of the resonance, and compare it to the experimental data.

Lightning Protection System for Space Shuttle

NASA Technical Reports Server (NTRS)

1977-01-01

The suitability and cost effectiveness of using a lightning mast for the shuttle service and access tower (SSAT) similar to the type used for the Apollo Soyuz Test Project (ASTP) mobile launcher (ML) was evaluated. Topics covered include: (1) ASTP launch damage to mast, mast supports, grounded overhead wires, and the instrumentation system; (2) modifications required to permit reusing the ASTP mast on the SSAT; (3) comparative costing factors per launch over a 10 year period in repetitive maintenance and refurbishment of the existing and modified masts, mast supports, grounded overhead wires, and ground instrumentation required to sustain mechanical and electrical integrity of the masts; (4) effects of blast testing samples of the ASTP ML type mast (corrosion and electrical flashover); (5) comparison of damages from ASTP launch and from blast testing.

Fission fragment driven neutron source

DOEpatents

Miller, Lowell G.; Young, Robert C.; Brugger, Robert M.

1976-01-01

Fissionable uranium formed into a foil is bombarded with thermal neutrons in the presence of deuterium-tritium gas. The resulting fission fragments impart energy to accelerate deuterium and tritium particles which in turn provide approximately 14 MeV neutrons by the reactions t(d,n).sup.4 He and d(t,n).sup.4 He.

Using secondary nuclear products for inferring the fuel areal density, convergence, and electron temperatures of deuterium filled implosions on the NIF

NASA Astrophysics Data System (ADS)

Lahmann, B.; Frenje, J. A.; Gatu Johnson, M.; Sio, H.; Kabadi, N. V.; Sutcliffe, G.; Seguin, F. H.; Li, C. K.; Petrasso, R. D.; Hartouni, E. P.; Rinderknecht, H. G.; Sayre, D. B.; Yeamans, C. B.; Khan, S. F.; Kyrala, G. A.; Lepape, S.; Berzak-Hopkins, L.; Meezan, N.; Bionta, R.; Ma, T.

2016-10-01

In deuterium-filled inertial confinement fusion implosions, 0.82 MeV 3He and 1.01 MeV T born from the primary DD reaction branches can undergo fusion reactions with the thermal deuterium plasma to create secondary D3He protons and DT neutrons respectively. In regimes of moderate fuel areal density (ρR 5 - 100 mg/cm2) the ratio of both of these secondary yields to the primary yield can be used to infer the fuel ρR, convergence, and an electron temperature (Te) simultaneously. This technique has been used on a myriad of deuterium filled implosion experiments on the NIF using the nuclear time of flight (NTOF) diagnostics to measure the secondary DT neutrons and CR-39 based wedge range filters (WRFs) to measure the secondary D3He protons. Additionally, a comparative study is conducted between the nuclear inferred convergence and x-ray inferred convergence obtained on these experiments. This work was supported in part by LLE, the U.S. DoE (NNSA, NLUF) and LLNL.

Refinement of the experimental dynamic structure factor for liquid para-hydrogen and ortho-deuterium using semi-classical quantum simulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Kyle K. G., E-mail: kylesmith@utexas.edu; Rossky, Peter J., E-mail: peter.rossky@austin.utexas.edu; Poulsen, Jens Aage, E-mail: jens72@chem.gu.se

The dynamic structure factor of liquid para-hydrogen and ortho-deuterium in corresponding thermodynamic states (T = 20.0 K, n = 21.24 nm{sup −3}) and (T = 23.0 K, n = 24.61 nm{sup −3}), respectively, has been computed by both the Feynman-Kleinert linearized path-integral (FK-LPI) and Ring-Polymer Molecular Dynamics (RPMD) methods and compared with Inelastic X Ray Scattering spectra. The combined use of computational and experimental methods enabled us to reduce experimental uncertainties in the determination of the true sample spectrum. Furthermore, the refined experimental spectrum of para-hydrogen and ortho-deuterium is consistently reproduced by both FK-LPI and RPMD results at momentum transfers lower than 12.8 nm{sup −1}.more » At larger momentum transfers the FK-LPI results agree with experiment much better for ortho-deuterium than for para-hydrogen. More specifically we found that for k ∼ 20.0 nm{sup −1} para-hydrogen provides a test case for improved approximations to quantum dynamics.« less

Is Deuterium Nuclear Fusion Catalyzed by Antineutrinos?

NASA Astrophysics Data System (ADS)

Shomer, Isaac

2010-02-01

The hypothesis of Fischbach and Jenkins that neutrinos emitted from the sun accelerate radioactive decay is noted. It is thought that neutrinos accelerate beta decay by reacting with neutron-rich nuclides to form a beta particle and a daughter product, with no antineutrino emitted. Conversely, it is proposed that antineutrinos can react with proton-rich nuclides to cause positron decay, with no neutrino emitted. It is also proposed that the nuclear fusion of the hydrogen bomb is triggered not only by the energy of the igniting fission bomb, but by the antineutrinos created by the rapid beta decay of the daughter products in the fission process. The contemplated mechanism for antineutrino initiated fusion is the following: 1. The antineutrinos from the fission daughter products cause positron decay of deuterium by the process outlined above. 2. In a later fusion step, these positrons subsequently react with neutrons in deuterium to create antineutrinos. Electrons are unavailable to annihilate positrons in the plasma of the hydrogen bomb. 3. These antineutrinos thereafter react with more deuterium to form positrons, thereby propagating a chain reaction. )

Deuterium incorporation experiments from (3R)- and (3S)-[3-2H]leucine into characteristic isoprenoidal lipid-core of halophilic archaea suggests the involvement of isovaleryl-CoA dehydrogenase.

PubMed

Yamauchi, Noriaki; Tanoue, Ryo

2017-11-01

The stereochemical reaction course for the two C-3 hydrogens of leucine to produce a characteristic isoprenoidal lipid in halophilic archaea was observed using incubation experiments with whole cell Halobacterium salinarum. Deuterium-labeled (3R)- and (3S)-[3- 2 H]leucine were freshly prepared as substrates from 2,3-epoxy-4-methyl-1-pentanol. Incorporation of deuterium from (3S)-[3- 2 H]leucine and loss of deuterium from (3R)-[3- 2 H]leucine in the lipid-core of H. salinarum was observed. Taken together with the results of our previous report, involving the incubation of chiral-labeled [5- 2 H]leucine, these results strongly suggested an involvement of isovaleryl-CoA dehydrogenase in leucine conversion to isoprenoid lipid in halophilic archaea. The stereochemical course of the reaction (anti-elimination) might have been the same as that previously reported for mammalian enzyme reactions. Thus, these results suggested that branched amino acids were metabolized to mevalonate in archaea in a manner similar to other organisms.

The water, deuterium, gas and uranium content of tektites

USGS Publications Warehouse

Friedman, I.

1958-01-01

The water content, deuterium concentration of the water, total gas and uranium contents were determined on tektite samples and other glass samples from Texas, Australia, Philippine Islands, Java, French Indo-China, Czechoslovakia, Libyan Desert, Billiton Island, Thailand, French West Africa, Peru, and New Mexico. The water content ranges from 0.24 per cent for the Peru tektite, to 0.0002 per cent for a moldavite. The majority of the tektites have less than 0.05 per cent water, and average 0.005 per cent H2O by weight. No other gases were detected, the lower detection limit being about 1 p.p.m. by weight. The deuterium content of the water in tektites is in the same range as that in terrestrial waters, and varies from 0.010 mole per cent to 0.0166 mole per cent deuterium. The uranium content is about from 1 to 3 p.p.m. The possible origin of tektites is discussed. The experimental data presented favour their being originally terrestrial, but produced by some catastrophic event. An extra-terrestrial source is not ruled out. ?? 1958.

Biomolecular Deuteration for Neutron Structural Biology and Dynamics.

PubMed

Haertlein, Michael; Moulin, Martine; Devos, Juliette M; Laux, Valerie; Dunne, Orla; Forsyth, V Trevor

2016-01-01

Neutron scattering studies provide important information in structural biology that is not accessible using other approaches. The uniqueness of the technique, and its complementarity with X-ray scattering, is greatest when full use is made of deuterium labeling. The ability to produce tailor-made deuterium-labeled biological macromolecules allows neutron studies involving solution scattering, crystallography, reflection, and dynamics to be optimized in a manner that has major impact on the scope, quality, and throughput of work in these areas. Deuteration facilities have now been developed at many neutron centres throughout the world; these are having a crucial effect on neutron studies in the life sciences and on biologically related studies in soft matter. This chapter describes methods that have been developed for the efficient production of deuterium-labeled samples for a wide range of neutron scattering applications. Examples are given that illustrate the use of these samples for each of the main techniques. Perspectives for biological deuterium labeling are discussed in relation to developments at current facilities and those that are planned in the future. © 2016 Elsevier Inc. All rights reserved.

Neutron yield when fast deuterium ions collide with strongly charged tritium-saturated dust particles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Akishev, Yu. S., E-mail: akishev@triniti.ru; Karal’nik, V. B.; Petryakov, A. V.

2017-02-15

The ultrahigh charging of dust particles in a plasma under exposure to an electron beam with an energy up to 25 keV and the formation of a flux of fast ions coming from the plasma and accelerating in the strong field of negatively charged particles are considered. Particles containing tritium or deuterium atoms are considered as targets. The calculated rates of thermonuclear fusion reactions in strongly charged particles under exposure to accelerated plasma ions are presented. The neutron generation rate in reactions with accelerated deuterium and tritium ions has been calculated for these targets. The neutron yield has been calculatedmore » when varying the plasma-forming gas pressure, the plasma density, the target diameter, and the beam electron current density. Deuterium and tritium-containing particles are shown to be the most promising plasmaforming gas–target material pair for the creation of a compact gas-discharge neutron source based on the ultrahigh charging of dust particles by beam electrons with an energy up to 25 keV.« less