Method to measure the position offset of multiple light spots in a distributed aperture laser angle measurement system.

Science.gov (United States)

Jing, Xiaoli; Cheng, Haobo; Xu, Chunyun; Feng, Yunpeng

2017-02-20

In this paper, an accurate measurement method of multiple spots' position offsets on a four-quadrant detector is proposed for a distributed aperture laser angle measurement system (DALAMS). The theoretical model is put forward, as well as the corresponding calculation method. This method includes two steps. First, as the initial estimation, integral approximation is applied to fit the distributed spots' offset function; second, the Boltzmann function is employed to compensate for the estimation error to improve detection accuracy. The simulation results attest to the correctness and effectiveness of the proposed method, and tolerance synthesis analysis of DALAMS is conducted to determine the maximum uncertainties of manufacturing and installation. The maximum angle error is less than 0.08° in the prototype distributed measurement system, which shows the stability and robustness for prospective applications.

Electron Generation and Transport in Intense Relativistic Laser-Plasma Interactions Relevant to Fast Ignition ICF

Energy Technology Data Exchange (ETDEWEB)

Ma, Tammy Yee Wing [Univ. of California, San Diego, CA (United States)

2010-01-01

The reentrant cone approach to Fast Ignition, an advanced Inertial Confinement Fusion scheme, remains one of the most attractive because of the potential to efficiently collect and guide the laser light into the cone tip and direct energetic electrons into the high density core of the fuel. However, in the presence of a preformed plasma, the laser energy is largely absorbed before it can reach the cone tip. Full scale fast ignition laser systems are envisioned to have prepulses ranging between 100 mJ to 1 J. A few of the imperative issues facing fast ignition, then, are the conversion efficiency with which the laser light is converted to hot electrons, the subsequent transport characteristics of those electrons, and requirements for maximum allowable prepulse this may put on the laser system. This dissertation examines the laser-to-fast electron conversion efficiency scaling with prepulse for cone-guided fast ignition. Work in developing an extreme ultraviolet imager diagnostic for the temperature measurements of electron-heated targets, as well as the validation of the use of a thin wire for simultaneous determination of electron number density and electron temperature will be discussed.

Measurement of the fast electron distribution in laser-plasma experiments in the context of the 'fast ignition' approach to inertial confinement fusion

International Nuclear Information System (INIS)

Batani, Dimitri; Morace, Alessio

2010-01-01

The recent 'fast ignition approach' to ICF relies on the presence of fast electrons to provide the 'external' ignition spark triggering the nuclear fusion reaction in the compressed core of a thermonuclear target. Such fast electron beam is produced by the interaction of a short-pulse high-intensity laser with the target itself. In this context, it becomes essential to characterize the density of fast electrons and their average energy (i.e. the 'laser to fast electron' energy conversion efficiency) but also the finer details of the velocity and angular distribution. In this work we will discuss several techniques used to determine the fast electron distribution function.

Fast ion beam-laser interactions

International Nuclear Information System (INIS)

Berry, H.G.; Young, L.; Engstroem, L.; Hardis, J.E.; Somerville, L.P.; Ray, W.J.; Kurtz, C.

1985-01-01

The authors are using collinear laser excitation of fast ion beams to study a number of atomic structure problems. The problems include the determination of fine and hyperfine structure in light positive and negative ions, plus measurements of absolute wavelengths of light from two-electron ions. In addition the authors intend to use a similar experimental arrangement to study excitation and decay of high Rydberg states first in the absence of fields and then in crossed electric and magnetic fields

Characterization of the fast electrons distribution produced in a high intensity laser target interaction

Energy Technology Data Exchange (ETDEWEB)

Westover, B. [Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California 92093 (United States); Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Chen, C. D.; Patel, P. K.; McLean, H. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Beg, F. N., E-mail: fbeg@ucsd.edu [Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California 92093 (United States)

2014-03-15

Experiments on the Titan laser (∼150 J, 0.7 ps, 2 × 10{sup 20} W cm{sup −2}) at the Lawrence Livermore National Laboratory were carried out in order to study the properties of fast electrons produced by high-intensity, short pulse laser interacting with matter under conditions relevant to Fast Ignition. Bremsstrahlung x-rays produced by these fast electrons were measured by a set of compact filter-stack based x-ray detectors placed at three angles with respect to the target. The measured bremsstrahlung signal allows a characterization of the fast electron beam spectrum, conversion efficiency of laser energy into fast electron kinetic energy and angular distribution. A Monte Carlo code Integrated Tiger Series was used to model the bremsstrahlung signal and infer a laser to fast electron conversion efficiency of 30%, an electron slope temperature of about 2.2 MeV, and a mean divergence angle of 39°. Simulations were also performed with the hybrid transport code ZUMA which includes fields in the target. In this case, a conversion efficiency of laser energy to fast electron energy of 34% and a slope temperature between 1.5 MeV and 4 MeV depending on the angle between the target normal direction and the measuring spectrometer are found. The observed temperature of the bremsstrahlung spectrum, and therefore the inferred electron spectrum are found to be angle dependent.

Ultra-fast movies of thin-film laser ablation

Science.gov (United States)

Domke, Matthias; Rapp, Stephan; Schmidt, Michael; Huber, Heinz P.

2012-11-01

Ultra-short-pulse laser irradiation of thin molybdenum films from the glass substrate side initiates an intact Mo disk lift off free from thermal effects. For the investigation of the underlying physical effects, ultra-fast pump-probe microscopy is used to produce stop-motion movies of the single-pulse ablation process, initiated by a 660-fs laser pulse. The ultra-fast dynamics in the femtosecond and picosecond ranges are captured by stroboscopic illumination of the sample with an optically delayed probe pulse of 510-fs duration. The nanosecond and microsecond delay ranges of the probe pulse are covered by an electronically triggered 600-ps laser. Thus, the setup enables an observation of general laser ablation processes from the femtosecond delay range up to the final state. A comparison of time- and space-resolved observations of film and glass substrate side irradiation of a 470-nm molybdenum layer reveals the driving mechanisms of the Mo disk lift off initiated by glass-side irradiation. Observations suggest that a phase explosion generates a liquid-gas mixture in the molybdenum/glass interface about 10 ps after the impact of the pump laser pulse. Then, a shock wave and gas expansion cause the molybdenum layer to bulge, while the enclosed liquid-gas mixture cools and condenses at delay times in the 100-ps range. The bulging continues for approximately 20 ns, when an intact Mo disk shears and lifts off at a velocity of above 70 m/s. As a result, the remaining hole is free from thermal effects.

Iodine laser of high efficiency and fast repetition rate

Energy Technology Data Exchange (ETDEWEB)

Hohla, K; Witte, K J

1976-07-01

The scaling laws of an iodine laser of high efficiency and fast repetition rate are reported. The laser is pumped with a new kind of low pressure Hg-UV-lamps which convert 32% of the electrical input in UV-light in the absorption band of the iodine laser and which can be fired up to 100 Hz. Details of a 10 kJ/1 nsec system as dimensions, energy density, repetition rate, flow velocity, gas composition and gas pressure and the overall efficiency are given which is expected to be about 2%.

Success Factors in Offset Deals: A Case Study Based Examination

OpenAIRE

Heinz Kirchwehm

2014-01-01

The requests for offset obligations occurs primarily in the area of arms imports and covers the full range of industrial and commercial benefits that companies provide to foreign governments as inducements or conditions for the purchase of military goods and services. Increasingly, all major contracts ask for offset obligations. They are now key differentiators in major contracts and it is a fast growing market. For the suppliers, offsets are a key differentiator in earning new business and t...

Fast ion generation by a picosecond high-power laser

Czech Academy of Sciences Publication Activity Database

Badziak, J.; Parys, P.; Wolowski, J.; Hora, H.; Krása, Josef; Láska, Leoš; Rohlena, Karel

2005-01-01

Roč. 35, č. 1 (2005), s. 5-22 ISSN 0078-5466 R&D Projects: GA MŠk(CZ) ME 238 Grant - others:International Atomic Energy in Vienna(XE) 11535/RO; State Commitee for Scientific Research (KBN)(PL) 1 PO3B 082 19 and 1 PO3B 043 26 Institutional research plan: CEZ:AV0Z10100523 Keywords : fast ion * plasma * picosecond laser Subject RIV: BH - Optics, Masers, Lasers Impact factor: 0.459, year: 2005

Loop-mirror laser neural network using a fast liquid-crystal display

NARCIS (Netherlands)

Mos, E.C.; Schleipen, J.J.H.B.; Waardt, de H.; Khoe, G.D.

1999-01-01

In our laser neural network (LNN) all-optical threshold action is obtained by application of controlled optical feedback to a laser diode. Here an extended experimental LNN is presented with as many as 32 neurons and 12 inputs. In the setup we use a fast liquid-crystal display to implement an

100 TW CPA Nd: Glass laser for fast ignition research

International Nuclear Information System (INIS)

Fujita, H.; Daido, H.; Jitsuno, T.

2001-01-01

A 100 TW chirped pulse amplification (CPA) Nd:glass laser has been developed to investigate the fast ignition concept. The ultrashort-pulse (60 TW, 42 J, 0.7 ps) was focused on plane targets, plane targets with preformed plasma, and high density compressed plasmas produced by the GEKKO-XII (12 beam, 20 kJ) laser. Focus intensity of >10 19 W/cm 2 has been achieved. (author)

Modulation format identification enabled by the digital frequency-offset loading technique for hitless coherent transceiver.

Science.gov (United States)

Fu, Songnian; Xu, Zuying; Lu, Jianing; Jiang, Hexun; Wu, Qiong; Hu, Zhouyi; Tang, Ming; Liu, Deming; Chan, Calvin Chun-Kit

2018-03-19

We propose a blind and fast modulation format identification (MFI) enabled by the digital frequency-offset (FO) loading technique for hitless coherent transceiver. Since modulation format information is encoded to the FO distribution during digital signal processing (DSP) at the transmitter side (Tx), we can use the fast Fourier transformation based FO estimation (FFT-FOE) method to obtain the FO distribution of individual data block after constant modulus algorithm (CMA) pre-equalization at the receiver side, in order to realize non-data-aided (NDA) and fast MFI. The obtained FO can be also used for subsequent FO compensation (FOC), without additional complexity. We numerically investigate and experimentally verify the proposed MFI with high accuracy and fast format switching among 28 Gbaud dual-polarization (DP)-4/8/16/64QAM, time domain hybrid-4/16QAM, and set partitioning (SP)-128QAM. In particular, the proposed MFI brings no performance degradation, in term of tolerance of amplified spontaneous emission (ASE) noise, laser linewidth, and fiber nonlinearity. Finally, a hitless coherent transceiver enabled by the proposed MFI with switching-block of only 2048 symbols is demonstrated over 1500 km standard single mode fiber (SSMF) transmission.

Lateral propagation of fast electrons at the laser-irradiated target surfaces

International Nuclear Information System (INIS)

Li, Y T; Lin, X X; Liu, B C; Du, F; Wang, S J; Li, C; Zhou, M L; Zhang, L; Liu, X; Wang, J; Liu, X L; Chen, L M; Wang, Z H; Ma, J L; Wei, Z Y; Zhang, J; Liu, F; Liu, F

2010-01-01

Lateral propagation of fast electrons at the target surfaces irradiated by femtosecond intense laser pulses is measured by k α x-ray imaging technique when a preplasma is presented. An annular halo surrounding a bright spot is observed in the x-ray images when the scale length of the electron density is large. For an incidence angle of 70 0 the x-ray images show a non-symmetrical distribution peaked to the laser propagation direction. The x-ray photons in the halo are mainly excited by the fast electrons that flow in the preplasma when their paths intersect the high density regions near the target surface.

Advantage of Fast Fourier Interpolation for laser modeling

International Nuclear Information System (INIS)

Epatko, I.V.; Serov, R.V.

2006-01-01

The abilities of a new algorithm: the 2-dimensional Fast Fourier Interpolation (FFI) with magnification factor (zoom) 2 n whose purpose is to improve the spatial resolution when necessary, are analyzed in details. FFI procedure is useful when diaphragm/aperture size is less than half of the current simulation scale. The computation noise due to FFI procedure is less than 10 -6 . The additional time for FFI is approximately equal to one Fast Fourier Transform execution time. For some applications using FFI procedure, the execution time decreases by a 10 4 factor compared with other laser simulation codes. (authors)

Fast ions and hot electrons in the laser--plasma interaction

International Nuclear Information System (INIS)

Gitomer, S.J.; Jones, R.D.; Begay, F.; Ehler, A.W.; Kephart, J.F.; Kristal, R.

1986-01-01

Data on the emission of energetic ions produced in laser--matter interactions have been analyzed for a wide variety of laser wavelengths, energies, and pulse lengths. Strong correlation has been found between the bulk energy per AMU for fast ions measured by charge cups and the x-ray-determined hot electron temperature. Five theoretical models have been used to explain this correlation. The models include (1) a steady-state spherically symmetric fluid model with classical electron heat conduction, (2) a steady-state spherically symmetric fluid model with flux limited electron heat conduction, (3) a simple analytic model of an isothermal rarefaction followed by a free expansion, (4) the lasneX hydrodynamics code [Comments Plasma Phys. Controlled Fusion 2, 85 (1975)], calculations employing a spherical expansion and simple initial conditions, and (5) the lasneX code with its full array of absorption, transport, and emission physics. The results obtained with these models are in good agreement with the experiments and indicate that the detailed shape of the correlation curve between mean fast ion energy and hot electron temperature is due to target surface impurities at the higher temperatures (higher laser intensities) and to the expansion of bulk target material at the lower temperatures (lower laser intensities)

Ultrahigh-brightness KrF laser system for fast ignition studies

International Nuclear Information System (INIS)

Shaw, M.J.; Ross, I.N.; Hooker, C.J.; Dodson, J.M.; Hirst, G.J.; Lister, J.M.D.; Divall, E.J.; Kidd, A.K.; Hancock, S.; Damerell, A.R.; Wyborn, B.E.

1999-01-01

The main requirements for a fast igniter laser beam are reviewed and shown to favour short wavelength and ultrahigh brightness. These requirements are met by the new KrF laser system at Rutherford Appleton Laboratory called TITANIA. TITANIA uses two schemes to enhance the laser beam brightness. The first is chirped pulse amplification which is used to enhance brightness by compressing the pulse into the femtosecond region. In this mode TITANIA produces in the region of 250 mJ on target in 700 fs. The second mode of operation uses a Raman technique for beam combining and beam clean-up which is designed to give a single beam of 80 Joules on target in a pulselength of 60 ps. In this scheme the KrF wavelength is Raman shifted to 268 nm. The Raman amplifiers will use gaseous rather than solid windows and experiments which demonstrate their feasibility will be described. A concept for a reactor scale fast igniter beam using the Raman technique will be discussed. (orig.)

Chromatin damage induced by fast neutrons or UV laser radiation

Energy Technology Data Exchange (ETDEWEB)

Radu, L.; Constantinescu, B.; Gazdaru, D.; Mihailescu, I

2002-07-01

Chromatin samples from livers of Wistar rats were subjected to fast neutron irradiation in doses of 10-100 Gy or to a 248 nm excimer laser radiation, in doses of 0.5-3 MJ.m{sup -2}. The action of the radiation on chromatin was monitored by chromatin intrinsic fluorescence and fluorescence lifetimes (of bound ethidium bromide to chromatin) and by analysing fluorescence resonance energy transfer between dansyl chloride and acridine orange coupled to chromatin. For the mentioned doses of UV excimer laser radiation, the action on chromatin was more intense than in the case of fast neutrons. The same types of damage are produced by the two radiations: acidic and basic destruction of chromatin protein structure, DNA strand breaking and the increase of the distance between DNA and proteins in chromatin. (author)

Chromatin damage induced by fast neutrons or UV laser radiation

International Nuclear Information System (INIS)

Radu, L.; Constantinescu, B.; Gazdaru, D.; Mihailescu, I.

2002-01-01

Chromatin samples from livers of Wistar rats were subjected to fast neutron irradiation in doses of 10-100 Gy or to a 248 nm excimer laser radiation, in doses of 0.5-3 MJ.m -2 . The action of the radiation on chromatin was monitored by chromatin intrinsic fluorescence and fluorescence lifetimes (of bound ethidium bromide to chromatin) and by analysing fluorescence resonance energy transfer between dansyl chloride and acridine orange coupled to chromatin. For the mentioned doses of UV excimer laser radiation, the action on chromatin was more intense than in the case of fast neutrons. The same types of damage are produced by the two radiations: acidic and basic destruction of chromatin protein structure, DNA strand breaking and the increase of the distance between DNA and proteins in chromatin. (author)

Laser pulse propagation and enhanced energy coupling to fast electrons in dense plasma gradients

International Nuclear Information System (INIS)

Gray, R J; Carroll, D C; Yuan, X H; Brenner, C M; Coury, M; Quinn, M N; Tresca, O; McKenna, P; Burza, M; Wahlström, C-G; Lancaster, K L; Neely, D; Lin, X X; Li, Y T

2014-01-01

Laser energy absorption to fast electrons during the interaction of an ultra-intense (10 20 W cm −2 ), picosecond laser pulse with a solid is investigated, experimentally and numerically, as a function of the plasma density scale length at the irradiated surface. It is shown that there is an optimum density gradient for efficient energy coupling to electrons and that this arises due to strong self-focusing and channeling driving energy absorption over an extended length in the preformed plasma. At longer density gradients the laser filaments, resulting in significantly lower overall energy coupling. As the scale length is further increased, a transition to a second laser energy absorption process is observed experimentally via multiple diagnostics. The results demonstrate that it is possible to significantly enhance laser energy absorption and coupling to fast electrons by dynamically controlling the plasma density gradient. (paper)

Wide and Fast Wavelength-Swept Fiber Laser Based on Dispersion Tuning for Dynamic Sensing

Directory of Open Access Journals (Sweden)

Shinji Yamashita

2009-01-01

Full Text Available We have developed a unique wide and fast wavelength-swept fiber laser for dynamic and accurate fiber sensing. The wavelength tuning is based on the dispersion tuning technique, which simply modulates the loss/gain in the dispersive laser cavity. By using wideband semiconductor optical amplifiers (SOAs, the sweep range could be as wide as ∼180 nm. Since the cavity contains no mechanical components, such as tunable filters, we could achieve very high sweep rate, as high as ∼200 kHz. We have realized the swept lasers at three wavelength bands, 1550 nm, 1300 nm, and 800 nm, using SOAs along with erbium-doped fiber amplifiers (EDFAs, and in two laser configurations, ring and linear ones. We also succeeded in applying the swept laser for a dynamic fiber-Bragg grating (FBG sensor system. In this paper, we review our researches on the wide and fast wavelength-swept fiber lasers.

Measurements of the divergence of fast electrons in laser-irradiated spherical targets

International Nuclear Information System (INIS)

Yaakobi, B.; Solodov, A. A.; Myatt, J. F.; Delettrez, J. A.; Stoeckl, C.; Froula, D. H.

2013-01-01

In recent experiments using directly driven spherical targets on the OMEGA laser system, the energy in fast electrons was found to reach ∼1% of the laser energy at an irradiance of ∼1.1 × 10 15 W/cm 2 . The fraction of these fast electrons absorbed in the compressed fuel shell depends on their angular divergence. This paper describes measurements of this divergence deduced from a series of shots where Mo-coated shells of increasing diameter (D) were suspended within an outer CH shell. The intensity of the Mo–Kα line and the hard x-ray radiation were found to increase approximately as ∼D 2 , indicating wide divergence of the fast electrons. Alternative interpretations of these results (electron scattering, radiation excitation of Kα, and an electric field due to return current) are shown to be unimportant

Pulsed laser deposition of HfO{sub 2} thin films on indium zinc oxide: Band offsets measurements

Energy Technology Data Exchange (ETDEWEB)

Craciun, D.; Craciun, V., E-mail: valentin.craciun@inflpr.ro

2017-04-01

Highlights: • High quality amorphous IZO and HfO{sub 2} films were obtained by PLD technique. • XPS measurements were used to obtain the valence band alignment in HfO{sub 2}/IZO heterostructure. • A valence band offset (ΔE{sub V}) of 1.75 eV was obtained for the HfO{sub 2}/IZO heterostructure. • A conduction band offset (ΔE{sub C}) of 0.65 eV was estimated for the HfO{sub 2}/IZO heterostructure. - Abstract: One of the most used dielectric films for amorphous indium zinc oxide (IZO) based thin films transistor is HfO{sub 2}. The estimation of the valence band discontinuity (ΔE{sub V}) of HfO{sub 2}/IZO heterostructure grown using the pulsed laser deposition technique, with In/(In + Zn) = 0.79, was obtained from X-ray photoelectron spectroscopy (XPS) measurements. The binding energies of Hf 4d5, Zn 2p3 and In 3d5 core levels and valence band maxima were measured for thick pure films and for a very thin HfO{sub 2} film deposited on a thick IZO film. A value of ΔE{sub V} = 1.75 ± 0.05 eV was estimated for the heterostructure. Taking into account the measured HfO{sub 2} and IZO optical bandgap values of 5.50 eV and 3.10 eV, respectively, a conduction band offset ΔE{sub C} = 0.65 ± 0.05 eV in HfO{sub 2}/IZO heterostructure was then obtained.

Laser fusion reactor design in a fast ignition with a dry wall chamber

International Nuclear Information System (INIS)

Ogawa, Yichi; Goto, Takuya; Ninomiya, Daisuke; Hiwatari, Ryoji; Asaoka, Yoshiyuki; Okano, Kunihiko

2007-01-01

One of the critical issues in laser fusion reactor design is high pulse heat load on the first wall by the X-rays and the fast/debris ions from fusion burn. There are mainly two concepts for the first wall of laser fusion reactor, a dry wall and a liquid metal wall. We should notice that the fast ignition method can achieve sufficiently high pellet gain with smaller (about 1/10 of the conventional central ignition method) input energy. To take advantage of this property, the design of a laser fusion reactor with a small size dry wall chamber may become possible. Since a small fusion pulse leads to a small electric power, high repetition of laser irradiation is required to keep sufficient electric power. Then we tried to design a laser fusion reactor with a dry wall chamber and a high repetition laser. This is a new challenging path to realize a laser fusion plant. Based on the point model of the core plasma, we have estimated that fusion energy in one pulse can be reduced to be 40 MJ with a pellet gain around G>100. To evaluate the validity of this simple estimation and to optimize the pellet design and the pulse shaping for the fast ignition scenario, we have introduced 1-D hydrodynamic simulation code ILESTA-1D and carried out implosion simulations. Since the code is one-dimensional, the detailed physics process of fast heating cannot be reproduced. Thus the fast heating is reflected in the code as the additional artificial heating source in the energy equation. It is modeled as a homogeneous heating of electrons in core region at the time just before when the maximum compression is achieved. At present we obtained the pellet gain G∝100 with the same input energy as the above estimation by a simple point model (350kJ for implosion, 50kJ for heating and assuming 20% coupling of heating laser). A dry wall is exposed to several threats due to the cyclic load by the high energy X-ray and charged particles: surface melting, physical and chemical sputtering

Fast elastic e-H(2s) scattering in laser fields

International Nuclear Information System (INIS)

Vucic, S.; Hewitt, R.; Hewitt, R.

1997-01-01

A numerical method for the evaluation of the Born endash Floquet amplitude for laser-assisted scattering is proposed for the case when a large basis set is required to achieve convergence. The method is applied to analyze the elastic scattering of fast electrons by the H(2s) state in a low-intensity laser field of varying frequency and to study the resonant scattering with increasing laser intensity. While the behavior of an atom in a resonant field of low intensity is determined by virtual transitions between resonant levels, at high intensity a great number of nonresonant virtual transitions may significantly influence laser-assisted processes. As a consequence, the attenuation of resonant effects could appear, as well as the open-quotes localclose quotes stabilization of the atom against ionization. copyright 1997 The American Physical Society

The theoretical and numerical models of the novel and fast tunable semiconductor ring laser

Science.gov (United States)

Zhu, Jiangbo; Zhang, Junwen; Chi, Nan; Yu, Siyuan

2011-01-01

Fast wavelength-tunable semiconductor lasers will be the key components in future optical packet switching networks. Especially, they are of great importance in the optical network nodes: transmitters, optical wavelength-routers, etc. In this paper, a new scheme of a next-generation fast tunable ring laser was given. Tunable lasers in this design have better wavelength tunability compared with others, for they are switched faster in wavelength and simpler to control with the injecting light from an external distributed Bragg-reflector(DBR). Then some discussion of the waveguide material system and coupler design of the ring laser were given. And we also derived the multimode rate equations corresponding to this scheme by analyzing some characteristics of the semiconductor ring cavity, directionality, nonlinear mode competition, optical injection locking, etc. We did MatLab simulation based on the new rate equations to research the process of mode competition and wavelength switching in the laser, and achieved the basic functions of a tunable laser. Finally some discussion of the impact of several key parameters was given.

Policy development for biodiversity offsets: a review of offset frameworks.

Science.gov (United States)

McKenney, Bruce A; Kiesecker, Joseph M

2010-01-01

Biodiversity offsets seek to compensate for residual environmental impacts of planned developments after appropriate steps have been taken to avoid, minimize or restore impacts on site. Offsets are emerging as an increasingly employed mechanism for achieving net environmental benefits, with offset policies being advanced in a wide range of countries (i.e., United States, Australia, Brazil, Colombia, and South Africa). To support policy development for biodiversity offsets, we review a set of major offset policy frameworks-US wetlands mitigation, US conservation banking, EU Natura 2000, Australian offset policies in New South Wales, Victoria, and Western Australia, and Brazilian industrial and forest offsets. We compare how the frameworks define offset policy goals, approach the mitigation process, and address six key issues for implementing offsets: (1) equivalence of project impacts with offset gains; (2) location of the offset relative to the impact site; (3) "additionality" (a new contribution to conservation) and acceptable types of offsets; (4) timing of project impacts versus offset benefits; (5) offset duration and compliance; and (6) "currency" and mitigation replacement ratios. We find substantial policy commonalities that may serve as a sound basis for future development of biodiversity offsets policy. We also identify issues requiring further policy guidance, including how best to: (1) ensure conformance with the mitigation hierarchy; (2) identify the most environmentally preferable offsets within a landscape context; and (3) determine appropriate mitigation replacement ratios.

Laser heating and magnetic compression of plasma in a fast solenoid

International Nuclear Information System (INIS)

Hoida, H.W.; Vlases, G.C.

1978-01-01

A low-β plasma column a few mm in diameter by 22 cm in length is heated by an axially directed CO 2 laser to a high-β state in a fast rising solenoidal field. Successful heating depends on proper timing between the laser pulse and rising field. Typical conditions attained are a line energy density of 6 J/cm, T-barapprox. =40 eV, and n/sub e/approx. =3 x 10 17 e - /cm 3 , with conditions quite uniform along the length. The heating suppresses instabilities which appear under certain conditions in the non-laser-heated case

Ultrafast Laser Engraving Method to Fabricate Gravure Plate for Printed Metal-Mesh Touch Panel

Directory of Open Access Journals (Sweden)

Weiyuan Chen

2015-10-01

Full Text Available In order to engrave gravure plate with fine lines structures, conventional art used lithography with dry/wet etching. Lithography with dry/wet etching method allows to engrave lines with smooth concave shape, but its disadvantages include difficulty in controlling aspect ratio, high and uniform in large size process, substrate material limitation due to etching solution availability, and process complexity. We developed ultra-fast laser technology to directly engrave a stainless plate, a gravure plate, to be used for fabricating 23 in. metal-mesh touch panel by gravure offset printing process. The technology employs high energy pulse to ablate materials from a substrate. Because the ultra-fast laser pulse duration is shorter than the energy dissipation time between material lattices, there is no heating issue during the ablation process. Therefore, no volcano-type protrusion on the engraved line edges occurs, leading to good printing quality. After laser engraving, we then reduce surface roughness of the gravure plate using electro-polishing process. Diamond like carbon (DLC coating layer is then added onto the surface to increase scratch resistance. We show that this procedure can fabricate gravure plate for gravure offset printing process with minimum printing linewidth 10.7 μm. A 23 in. metal-mesh pattern was printed using such gravure plate and fully functional touch panel was demonstrated in this work.

Analysis of effects of laser profiles on fast electron generation by two-dimensional Particle-In-Cell simulations

International Nuclear Information System (INIS)

Hata, M.

2010-01-01

Complete text of publication follows. A cone-guided target is used in the Fast Ignition Realization Experiment project phase-I (FIREX-I) and optimization of its design is performed. However a laser profile is not optimized much, because the laser profile that is the best for core heating is not known well. To find that, it is useful to investigate characteristics of generated fast electrons in each condition of different laser profiles. In this research, effects of laser profiles on fast electron generation are investigated on somewhat simple conditions by two-dimensional Particle-In-Cell simulations. In these simulations, a target is made up of Au pre-plasma and Au plasma. The Au pre-plasma has the exponential profile in the x direction with the scale length L = 4.0 μm and the density from 0.10 n cr to 20 n cr . The Au plasma has the flat profile in the x direction with 10 μm width and 20 n cr . Plasma profiles are uniform in the y direction. The ionization degree and the mass number of plasmas are 40 and 197, where the ionization degree is determined by PINOCO simulations. PINOCO is a two-dimensional radiation hydrodynamics simulation code, which simulates formation of the high-density plasma during the compression phase in the fast ignition. A laser is assumed to propagate as plane wave from the negative x direction to the positive x direction. Laser profiles are supposed to be uniform in the y direction. Three different laser profiles, namely flat one with t flat = 100 fs, Gaussian one with t rise/fall = 47.0 fs and flat + Gaussian one with t rise/fall = 23.5 fs and t flat = 50 fs are used. The energy and the peak intensity are constant with E = 10 7 J/cm 2 and I L = 10 20 W/cm 2 in all cases of different laser profiles. We compare results in each condition of three different laser profiles and investigate effects of laser profiles on fast electron generation. Time-integrated energy spectra are similar in all cases of three different laser profiles. In the

Joint channel/frequency offset estimation and correction for coherent optical FBMC/OQAM system

Science.gov (United States)

Wang, Daobin; Yuan, Lihua; Lei, Jingli; wu, Gang; Li, Suoping; Ding, Runqi; Wang, Dongye

2017-12-01

In this paper, we focus on analysis of the preamble-based joint estimation for channel and laser-frequency offset (LFO) in coherent optical filter bank multicarrier systems with offset quadrature amplitude modulation (CO-FBMC/OQAM). In order to reduce the noise impact on the estimation accuracy, we proposed an estimation method based on inter-frame averaging. This method averages the cross-correlation function of real-valued pilots within multiple FBMC frames. The laser-frequency offset is estimated according to the phase of this average. After correcting LFO, the final channel response is also acquired by averaging channel estimation results within multiple frames. The principle of the proposed method is analyzed theoretically, and the preamble structure is thoroughly designed and optimized to suppress the impact of inherent imaginary interference (IMI). The effectiveness of our method is demonstrated numerically using different fiber and LFO values. The obtained results show that the proposed method can improve transmission performance significantly.

Regenerative similariton laser

Directory of Open Access Journals (Sweden)

Thibault North

2016-05-01

Full Text Available Self-pulsating lasers based on cascaded reshaping and reamplification (2R are capable of initiating ultrashort pulses despite the accumulation of large amounts of nonlinearities in all-fiber resonators. The spectral properties of pulses in self-similar propagation are compatible with cascaded 2R regeneration by offset filtering, making parabolic pulses suitable for the design of a laser of this recently introduced class. A new type of regenerative laser giving birth to similaritons is numerically investigated and shows that this laser is the analog of regenerative sources based solely on self-phase modulation and offset filtering. The regenerative similariton laser does not suffer from instabilities due to excessive nonlinearities and enables ultrashort pulse generation in a simple cavity configuration.

Fast optical shutters for Nova, a high power fusion laser

International Nuclear Information System (INIS)

Bradley, L.P.; Gagnon, W.L.; Carder, B.M.

1977-01-01

Preliminary design and performance test results for fast optical shutters intended for use in the Nova high power fusion laser system are briefly described. Both an opening shutter to protect the pellet target from amplified spontaneous emission (ASE), and a closing shutter to protect the laser from light reflected back from the target are discussed. Faraday rotators, synchronized by a 400 Hz oscillator, provide an opening shutter mechanism with an opening time of approximately 10 μs. A plasma closing shutter, employing electrical sublimation of a foil, provide a shutter closing time of 70 ns +- 20 ns. Energy for foil sublimation is provided by discharge of a 42 J capacitor bank. Implementation of these shutter techniques in the Nova system is anticipated to improve laser output power and efficiency

Fast physical random bit generation with chaotic semiconductor lasers

Science.gov (United States)

Uchida, Atsushi; Amano, Kazuya; Inoue, Masaki; Hirano, Kunihito; Naito, Sunao; Someya, Hiroyuki; Oowada, Isao; Kurashige, Takayuki; Shiki, Masaru; Yoshimori, Shigeru; Yoshimura, Kazuyuki; Davis, Peter

2008-12-01

Random number generators in digital information systems make use of physical entropy sources such as electronic and photonic noise to add unpredictability to deterministically generated pseudo-random sequences. However, there is a large gap between the generation rates achieved with existing physical sources and the high data rates of many computation and communication systems; this is a fundamental weakness of these systems. Here we show that good quality random bit sequences can be generated at very fast bit rates using physical chaos in semiconductor lasers. Streams of bits that pass standard statistical tests for randomness have been generated at rates of up to 1.7 Gbps by sampling the fluctuating optical output of two chaotic lasers. This rate is an order of magnitude faster than that of previously reported devices for physical random bit generators with verified randomness. This means that the performance of random number generators can be greatly improved by using chaotic laser devices as physical entropy sources.

Automated assembly of fast-axis collimation (FAC) lenses for diode laser bar modules

Science.gov (United States)

Miesner, Jörn; Timmermann, Andre; Meinschien, Jens; Neumann, Bernhard; Wright, Steve; Tekin, Tolga; Schröder, Henning; Westphalen, Thomas; Frischkorn, Felix

2009-02-01

Laser diodes and diode laser bars are key components in high power semiconductor lasers and solid state laser systems. During manufacture, the assembly of the fast axis collimation (FAC) lens is a crucial step. The goal of our activities is to design an automated assembly system for high volume production. In this paper the results of an intermediate milestone will be reported: a demonstration system was designed, realized and tested to prove the feasibility of all of the system components and process features. The demonstration system consists of a high precision handling system, metrology for process feedback, a powerful digital image processing system and tooling for glue dispensing, UV curing and laser operation. The system components as well as their interaction with each other were tested in an experimental system in order to glean design knowledge for the fully automated assembly system. The adjustment of the FAC lens is performed by a series of predefined steps monitored by two cameras concurrently imaging the far field and the near field intensity distributions. Feedback from these cameras processed by a powerful and efficient image processing algorithm control a five axis precision motion system to optimize the fast axis collimation of the laser beam. Automated cementing of the FAC to the diode bar completes the process. The presentation will show the system concept, the algorithm of the adjustment as well as experimental results. A critical discussion of the results will close the talk.

Conceptual design of a fast-ignition laser fusion reactor FALCON-D

International Nuclear Information System (INIS)

Goto, T.; Ogawa, Y.; Okano, K.; Hiwatari, R.; Asaoka, Y.; Someya, Y.; Sunahara, A.; Johzaki, T.

2008-10-01

A new conceptual design of the laser fusion power plant FALCON-D (Fast ignition Advanced Laser fusion reactor CONcept with a Dry wall chamber) has been proposed. The fast ignition method can achieve the sufficient fusion gain for a commercial operation (∼100) with about 10 times smaller fusion yield than the conventional central ignition method. FALCON-D makes full use of this property and aims at designing with a compact dry wall chamber (5 - 6 m radius). 1-D/2-D hydrodynamic simulations showed the possibility of the sufficient gain achievement with a 40 MJ target yield. The design feasibility of the compact dry wall chamber and solid breeder blanket system was shown through the thermomechanical analysis of the dry wall and neutronics analysis of the blanket system. A moderate electric output (∼400 MWe) can be achieved with a high repetition (30 Hz) laser. This dry wall concept not only reduces some difficulties accompanied with a liquid wall but also enables a simple cask maintenance method for the replacement of the blanket system, which can shorten the maintenance time. The basic idea of the maintenance method for the final optics system has also been proposed. Some critical R and D issues required for this design are also discussed. (author)

Fast automotive diesel exhaust measurement using quantum cascade lasers

Science.gov (United States)

Herbst, J.; Brunner, R.; Lambrecht, A.

2013-12-01

Step by step, US and European legislations enforce the further reduction of atmospheric pollution caused by automotive exhaust emissions. This is pushing automotive development worldwide. Fuel efficient diesel engines with SCRtechnology can impede NO2-emission by reduction with NH3 down to the ppm range. To meet the very low emission limits of the Euro6 resp. US NLEV (National Low Emission Vehicle) regulations, automotive manufacturers have to optimize continuously all phases of engine operation and corresponding catalytic converters. Especially nonstationary operation holds a high potential for optimizing gasoline consumption and further reducing of pollutant emissions. Test equipment has to cope with demanding sensitivity and speed requirements. In the past Fraunhofer IPM has developed a fast emission analyzer called DEGAS (Dynamic Exhaust Gas Analyzer System), based on cryogenically cooled lead salt lasers. These systems have been used at Volkswagen AG`s test benches for a decade. Recently, IPM has developed DEGAS-Next which is based on cw quantum cascade lasers and thermoelectrically cooled detectors. The system is capable to measure three gas components (i.e. NO, NO2, NH3) in two channels with a time resolution of 20 ms and 1 ppm detection limits. We shall present test data and a comparison with fast FTIR measurements.

High-intensity subpicosecond laser pulse propagation in a 1-cm capillary tube and fast ignitor experiments

International Nuclear Information System (INIS)

Malka, G.; Courtois, C.; Cros, B.; Matthieussent, G.; Borghesi, M.; Gaillard, R.; Mackinnon, A.J.; Willi, O.; Danson, C.; Neely, D.; Altenberd, D.; Feurer, T.; Forster, E.; Gibbon, P.; Sauerbray, R.; Teubner, U.; Theobald, W.; Uschmann, I.; Amiranoff, F.; Baton, S.; Gremillet, L.; Fuchs, J.; Marques, J.R.; Gallant, P.; Kieffer, J.C.; Pepin, H.; Adam, J.C.; Heron, A.; Laval, G.; Mora, P.

2000-01-01

We present an abstract of ultra short and intense laser plasma interaction experiments which were performed with the 100 TW P102 laser facility at CEA/Limeil-Valenton. Laser interaction at relativistic regime (I>10 18 W/cm 2 ) has been investigated with different 'targets': overdense plasma, underdense plasma, free electrons and capillary tube. These experiments are of great interests for the Fast Ignitor concept and the Laser Particle Accelerator. (authors)

Fast ion generation in femto- and picosecond laser plasma at low fluxes of heating radiation

International Nuclear Information System (INIS)

Faenov, A.Ya.; Pikuz, T.A.; Magunov, A.I.

2006-01-01

X-ray spectra from fluoroplastic targets irradiated by laser pulses with duration of 60 fs to 1 ps have been investigated experimentally. It is shown that, when the contrast of the laser pulse is sufficiently low, the effect of self-focusing of the main laser pulse in the plasma produced by the prepulse can significantly enhance the generation efficiency of fast particles. In this case, ions with energies as high as ∼1 MeV are observed at relatively low laser intensities [ru

Plasma physics study and laser development for the fast ignition realization experiment (FIREX) project

International Nuclear Information System (INIS)

Azechi, H.; Mima, K.; Fujimoto, Y.

2008-10-01

Since the approval of the first phase of Fast Ignition Realization Experiment (FIREX-I), we have devoted our efforts on designing advanced targets and constructing the world highest-energy Peta Watt laser. The new target design has the following features. The coupling efficiency from the heating laser to the thermal energy of the compressed core plasma can be increased by the two ways:1) Low-Z foam layer on the inner surface of the cone for optimum absorption. 2) Double cone. Electrons generated in the inner surface of the double cone will return by sheathe potential generated between two cones. The implosion performance can be improved by three ways: 3) Low-Z plastic layer on the outer surface of the cone may suppress the expansion of the Au cone that flows into the interior of the compressed core. 4) Br doped plastic ablator may significantly moderate the Rayleigh-Taylor instability, making implosion more stable. 5) Evacuation of the target center to prevent gas jets from destroying the cone tip. For project robustness, we also explore 6) impact ignition scheme that eliminates complexity of laser-plasma interaction while keeping the compactness advantage of fast ignition. The fully integrated fast ignition experiment is scheduled on 2009. If subsequent FIREX-II will start as proposed, the ignition and burn will be demonstrated shortly after the ignition at NIF and LMJ, providing a scientific database of both central and fast ignition. (author)

High-intensity subpicosecond laser pulse propagation in a 1-cm capillary tube and fast ignitor experiments

Energy Technology Data Exchange (ETDEWEB)

Malka, G.; Courtois, C.; Cros, B.; Matthieussent, G. [Paris-11 Univ., 91 - Orsay (France). Lab. de Physique des Gaz et des Plasmas; Blanchot, N.; Bonnaud, G.; Busquet, M.; Canaud, B.; Desenne, D.; Diskier, L.; Garconnet, J.P.; Louis-Jacquet, M.; Lefebvre, E.; Lours, L.; Mens, A.; Miquel, J.L.; Peyrusse, O.; Rousseaux, C. [CEA/Limeil Valenton, 94 - Villeneuve Saint Georges (France); Borghesi, M.; Gaillard, R.; Mackinnon, A.J.; Willi, O. [Imperial Coll., Plasma Physics Groups, London (United Kingdom); Danson, C.; Neely, D. [Rutherford Appleton Lab., Chilton (United Kingdom); Altenberd, D.; Feurer, T.; Forster, E.; Gibbon, P.; Sauerbray, R.; Teubner, U.; Theobald, W.; Uschmann, I. [Institut fur Optik und Quantenelektronik, Jena (Germany); Amiranoff, F.; Baton, S.; Gremillet, L.; Fuchs, J.; Marques, J.R. [Ecole Polytechnique, Lab. d' Utilisation de Lasers Intenses, CNRS-CEA, 91 - Palaiseau (France); Gallant, P.; Kieffer, J.C.; Pepin, H. [INRS Energie et Materiaux, Quebec (Canada); Adam, J.C.; Heron, A.; Laval, G.; Mora, P. [Ecole Polytechnique, 91 - Palaiseau (France). Centre de Physique Theorique

2000-07-01

We present an abstract of ultra short and intense laser plasma interaction experiments which were performed with the 100 TW P102 laser facility at CEA/Limeil-Valenton. Laser interaction at relativistic regime (I>10{sup 18} W/cm{sup 2}) has been investigated with different 'targets': overdense plasma, underdense plasma, free electrons and capillary tube. These experiments are of great interests for the Fast Ignitor concept and the Laser Particle Accelerator. (authors)

Super fast physical-random number generation using laser diode frequency noises

Science.gov (United States)

Ushiki, Tetsuro; Doi, Kohei; Maehara, Shinya; Sato, Takashi; Ohkawa, Masashi; Ohdaira, Yasuo

2011-02-01

Random numbers can be classified as either pseudo- or physical-random in character. Pseudo-random numbers' periodicity renders them inappropriate for use in cryptographic applications, but naturally-generated physical-random numbers have no calculable periodicity, thereby making them ideally-suited to the task. The laser diode naturally produces a wideband "noise" signal that is believed to have tremendous capacity and great promise, for the rapid generation of physical-random numbers for use in cryptographic applications. We measured a laser diode's output, at a fast photo detector and generated physical-random numbers from frequency noises. We then identified and evaluated the binary-number-line's statistical properties. The result shows that physical-random number generation, at speeds as high as 40Gbps, is obtainable, using the laser diode's frequency noise characteristic.

Efficient Fixed-Offset GPR Scattering Analysis

DEFF Research Database (Denmark)

Meincke, Peter; Chen, Xianyao

2004-01-01

The electromagnetic scattering by buried three-dimensional penetrable objects, as involved in the analysis of ground penetrating radar systems, is calculated using the extended Born approximation. The involved scattering tensor is calculated using fast Fourier transforms (FFT's). We incorporate...... in the scattering calculation the correct radiation patterns of the ground penetrating radar antennas by using their plane-wave transmitting and receiving spectra. Finally, we derive an efficient FFT-based method to analyze a fixed-offset configuration in which the location of the transmitting antenna is different...

Development of a Fiber-Optics Microspatially Offset Raman Spectroscopy Sensor for Probing Layered Materials.

Science.gov (United States)

Vandenabeele, Peter; Conti, Claudia; Rousaki, Anastasia; Moens, Luc; Realini, Marco; Matousek, Pavel

2017-09-05

Microspatially offset Raman spectroscopy (micro-SORS) has been proposed as a valuable approach to sample molecular information from layers that are covered by a turbid (nontransparent) layer. However, when large magnifications are involved, the approach is not straightforward, as spatial constraints exist to position the laser beam and the objective lens with the external beam delivery or, with internal beam delivery, the maximum spatial offset achievable is restricted. To overcome these limitations, we propose here a prototype of a new micro-SORS sensor, which uses bare glass fibers to transfer the laser radiation to the sample and to collect the Raman signal from a spatially offset zone to the Raman spectrometer. The concept also renders itself amenable to remote delivery and to the miniaturization of the probe head which could be beneficial for special applications, e.g., where access to sample areas is restricted. The basic applicability of this approach was demonstrated by studying several layered structure systems. Apart from proving the feasibility of the technique, also, practical aspects of the use of the prototype sensor are discussed.

Research on imploded plasma heating by short pulse laser for fast ignition

International Nuclear Information System (INIS)

Kodama, R.; Kitagawa, Y.; Mima, K.

2001-01-01

Since the peta watt module (PWM) laser was constructed in 1995, investigated are heating processes of imploded plasmas by intense short pulse lasers. In order to heat the dense plasma locally, a heating laser pulse should be guided into compressed plasmas as deeply as possible. Since the last IAEA Fusion Conference, the feasibility of fast ignition has been investigated by using the short pulse GEKKO MII glass laser and the PWM laser with GEKKO XII laser. We found that relativistic electrons are generated efficiently in a preformed plasma to heat dense plasmas. The coupling efficiency of short pulse laser energy to a solid density plasma is 40% when no plasmas are pre-formed, and 20% when a large scale plasma is formed by a long pulse laser pre-irradiation. The experimental results are confirmed by numerical simulations using the simulation code 'MONET' which stands for the Monte-Carlo Electron Transport code developed at Osaka. In the GEKKO XII and PWM laser experiments, intense heating pulses are injected into imploded plasmas. As a result of the injection of heating pulse, it is found that high energy electrons and ions could penetrate into imploded core plasmas to enhance neutron yield by factor 3∼5. (author)

Signal enhancement of neutral He emission lines by fast electron bombardment of laser-induced He plasma

Directory of Open Access Journals (Sweden)

Hery Suyanto

2016-08-01

Full Text Available A time-resolved spectroscopic study is performed on the enhancement signals of He gas plasma emission using nanosecond (ns and picosecond (ps lasers in an orthogonal configuration. The ns laser is used for the He gas plasma generation and the ps laser is employed for the ejection of fast electrons from a metal target, which serves to excite subsequently the He atoms in the plasma. The study is focused on the most dominant He I 587.6 nm and He I 667.8 nm emission lines suggested to be responsible for the He-assisted excitation (HAE mechanism. The time-dependent intensity enhancements induced by the fast electrons generated with a series of delayed ps laser ablations are deduced from the intensity time profiles of both He emission lines. The results clearly lead to the conclusion that the metastable excited triplet He atoms are actually the species overwhelmingly produced during the recombination process in the ns laser-induced He gas plasma. These metastable He atoms are believed to serve as the major energy source for the delayed excitation of analyte atoms in ns laser-induced breakdown spectroscopy (LIBS using He ambient gas.

Signal enhancement of neutral He emission lines by fast electron bombardment of laser-induced He plasma

Energy Technology Data Exchange (ETDEWEB)

Suyanto, Hery [Department of Physics, Faculty of Mathematics and Natural Sciences, Udayana University, Kampus Bukit Jimbaran, Denpasar 80361, Bali (Indonesia); Pardede, Marincan [Department of Electrical Engineering, University of Pelita Harapan, 1100 M.H. Thamrin Boulevard, Lippo Village, Tangerang 15811 (Indonesia); Hedwig, Rinda [Department of Computer Engineering, Bina Nusantara University, 9 K.H. Syahdan, Jakarta 14810 (Indonesia); Marpaung, Alion Mangasi [Department of Physics, Faculty of Mathematics and Natural Sciences, Jakarta State University, Rawamangun, Jakarta 12440 (Indonesia); Ramli, Muliadi [Department of Chemistry, Faculty of Mathematics and Natural Sciences, Syiah Kuala University, Darussalam, Banda Aceh 23111, NAD (Indonesia); Lie, Tjung Jie; Kurniawan, Koo Hendrik, E-mail: kurnia18@cbn.net.id [Research Center of Maju Makmur Mandiri Foundation, 40 Srengseng Raya, Kembangan, Jakarta Barat 11630 (Indonesia); Abdulmadjid, Syahrun Nur [Department of Physics, Faculty of Mathematics and Natural Sciences, Syiah Kuala University, Darussalam, Banda Aceh 23111, NAD (Indonesia); Tjia, May On [Research Center of Maju Makmur Mandiri Foundation, 40 Srengseng Raya, Kembangan, Jakarta Barat 11630 (Indonesia); Physics of Magnetism and Photonics Group, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, 10 Ganesha,Bandung 40132 (Indonesia); Kagawa, Kiichiro [Research Center of Maju Makmur Mandiri Foundation, 40 Srengseng Raya, Kembangan, Jakarta Barat 11630 (Indonesia); Fukui Science Education Academy, Takagi Chuo 2 chome, Fukui 910-0804 (Japan)

2016-08-15

A time-resolved spectroscopic study is performed on the enhancement signals of He gas plasma emission using nanosecond (ns) and picosecond (ps) lasers in an orthogonal configuration. The ns laser is used for the He gas plasma generation and the ps laser is employed for the ejection of fast electrons from a metal target, which serves to excite subsequently the He atoms in the plasma. The study is focused on the most dominant He I 587.6 nm and He I 667.8 nm emission lines suggested to be responsible for the He-assisted excitation (HAE) mechanism. The time-dependent intensity enhancements induced by the fast electrons generated with a series of delayed ps laser ablations are deduced from the intensity time profiles of both He emission lines. The results clearly lead to the conclusion that the metastable excited triplet He atoms are actually the species overwhelmingly produced during the recombination process in the ns laser-induced He gas plasma. These metastable He atoms are believed to serve as the major energy source for the delayed excitation of analyte atoms in ns laser-induced breakdown spectroscopy (LIBS) using He ambient gas.

Noise-based frequency offset modulation in wideband frequency-selective fading channels

NARCIS (Netherlands)

Meijerink, Arjan; Cotton, S.L.; Bentum, Marinus Jan; Scanlon, W.G.

2009-01-01

A frequency offset modulation scheme using wideband noise carriers is considered. The main advantage of such a scheme is that it enables fast receiver synchronization without channel adaptation, while providing robustness to multipath fading and in-band interference. This is important for low-power

Enhanced hole boring with two-color relativistic laser pulses in the fast ignition scheme

Energy Technology Data Exchange (ETDEWEB)

Yu, Changhai; Tian, Ye; Li, Wentao; Wang, Wentao; Zhang, Zhijun; Qi, Rong; Wang, Cheng [State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Deng, Aihua, E-mail: aihuadeng1985@gmail.com [Department of Physics and Astronomy, University of California, Los Angeles, California 90095 (United States); Liu, Jiansheng, E-mail: michaeljs-liu@siom.ac.cn [State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Collaborative Innovation Center of IFSA (CICIFSA), Shanghai Jiao Tong University, Shanghai 200240 (China)

2016-08-15

A scheme of using two-color laser pulses for hole boring into overdense plasma as well as energy transfer into electron and ion beams has been studied using particle-in-cell simulations. Following an ultra-short ultra-intense hole-boring laser pulse with a short central wavelength in extreme ultra-violet range, the main infrared driving laser pulse can be guided in the hollow channel preformed by the former laser and propagate much deeper into an overdense plasma, as compared to the case using the infrared laser only. In addition to efficiently transferring the main driving laser energy into energetic electrons and ions generation deep inside the overdense plasma, the ion beam divergence can be greatly reduced. The results might be beneficial for the fast ignition concept of inertial confinement fusion.

Ultra High Intensity laser produced fast electron transport in under-dense and over-dense matter

International Nuclear Information System (INIS)

Manclossi, Mauro

2006-01-01

This thesis is related to inertial fusion research, and particularly concerns the approach to fast ignition, which is based on the use of ultra-intense laser pulses to ignite the thermonuclear fuel. Until now, the feasibility of this scheme has not been proven and depends on many fundamental aspects of the underlying physics, which are not yet fully understood and which are also very far from controls. The main purpose of this thesis is the experimental study of transport processes in the material over-dense (solid) and under-dense (gas jet) of a beam of fast electrons produced by pulse laser at a intensity of some 10 19 Wcm -2 . (author)

Fast all-optical flip-flop based on a single distributed feedback laser diode.

Science.gov (United States)

Huybrechts, Koen; Morthier, Geert; Baets, Roel

2008-07-21

Since there is an increasing demand for fast networks and switches, the electronic data processing imposes a severe bottleneck and all-optical processing techniques will be required in the future. All-optical flip-flops are one of the key components because they can act as temporary memory elements. Several designs have already been demonstrated but they are often relatively slow or complex to fabricate. We demonstrate experimentally fast flip-flop operation in a single DFB laser diode which is one of the standard elements in today's telecommunication industry. Injecting continuous wave light in the laser diode, a bistability is obtained due to the spatial hole burning effect. We can switch between the two states by using pulses with energies below 200 fJ resulting in flip-flop operation with switching times below 75 ps and repetition rates of up to 2 GHz.

Fast random-number generation using a diode laser's frequency noise characteristic

Science.gov (United States)

Takamori, Hiroki; Doi, Kohei; Maehara, Shinya; Kawakami, Kohei; Sato, Takashi; Ohkawa, Masashi; Ohdaira, Yasuo

2012-02-01

Random numbers can be classified as either pseudo- or physical-random, in character. Pseudo-random numbers are generated by definite periodicity, so, their usefulness in cryptographic applications is somewhat limited. On the other hand, naturally-generated physical-random numbers have no calculable periodicity, thereby making them ideal for the task. Diode lasers' considerable wideband noise gives them tremendous capacity for generating physical-random numbers, at a high rate of speed. We measured a diode laser's output with a fast photo detector, and evaluated the binary-numbers from the diode laser's frequency noise characteristics. We then identified and evaluated the binary-number-line's statistical properties. We also investigate the possibility that much faster physical-random number parallel-generation is possible, using separate outputs of different optical-path length and character, which we refer to as "coherence collapse".

Petawatt laser system for fast ignitor studies at ILE, Osaka University

International Nuclear Information System (INIS)

Izawa, Y.; Kitagawa, Y.; Fujita, H.

2003-01-01

A petawatt laser system has been developed for the fast ignitor studies. Three new technologies were introduced; an optical parametric chirped pulse amplifier (OPCPA) in the front end for suppression of prepulse below 10 -8 the main pulse, a deformable mirror for correction of wave front distortion and the chirped pulse amplification in the GEKKO-XII. The system delivered successfully the output energy of 420 J in 470 fs on target, which corresponds to the focal intensity of more than 10 20 W/cm 2 . By using the PW laser, the heating experiments of the high density plasma imploded by GEKKO-XII started. (author)

Pulsed Nd-YAG laser welding of Prototype Fast Breeder Reactor fuel elements

International Nuclear Information System (INIS)

Suresh Varma, P.V.; Gupta, Amit; Amit, K.; Bhatt, R.B.; Afzal, Mohd.; Panakkal, J.P.; Kamath, H.S.

2009-02-01

End plug welding of Prototype Fast Breeder Reactor (PFBR) fuel elements involves welding of fully Austenitic Stainless Steel (ASS) of grade D9 clad tube with 316M end plug. Pulsed Gas Tungsten Arc Welding (GTAW) is being used for the production of PFBR fuel elements at Advanced Fuel Fabrication Facility (AFFF). GTAW is an established process for end plug welding and hence adopted by many countries. GTAW has got certain limitations like heat input, arc gap sensitivity and certain sporadic defects like tungsten inclusion. Experiments have been carried out at AFFF to use Laser Beam Welding (LBW) technique as LBW offers a number of advantages over the former process. This report mainly deals with the optimization of laser parameters for welding of PFBR fuel elements. To facilitate pulsed Nd-YAG laser spot welding, parameters like peak power, pulse duration, pulse energy, frequency and defocusing of laser beam on to the work piece have been optimized. On the basis of penetration requirement laser welding parameters have been optimized. (author)

Offset drilling obligations

International Nuclear Information System (INIS)

Boyd, K.D.; Kalmakoff, J.J.

1998-01-01

A review of the 'offset well' clause found in freehold and Crown natural gas and petroleum leases was presented. The objective was to provide lessors and lessees with a clear understanding of the rights and obligations associated with offset wells. It was noted that offset well obligations vary according to the form of lease used, the type of offsetting well, the regulatory regime and the geophysical characteristics of the producing formation. Some suggestions were made as to how current versions of the offset well clause can be amended to overcome some of the problems encountered in applying the clause to an offset horizontal well that has been drilled on adjoining lands. Failure to resolve the new issues presented by horizontal drilling technology in terms of documentation, which records respective rights and obligations on the basis of generally accepted principles, will result in large numbers of conflicts and unnecessary litigation. 144 refs., 1 fig

Fast femtosecond laser ablation for efficient cutting of sintered alumina substrates

Science.gov (United States)

Oosterbeek, Reece N.; Ward, Thomas; Ashforth, Simon; Bodley, Owen; Rodda, Andrew E.; Simpson, M. Cather

2016-09-01

Fast, accurate cutting of technical ceramics is a significant technological challenge because of these materials' typical high mechanical strength and thermal resistance. Femtosecond pulsed lasers offer significant promise for meeting this challenge. Femtosecond pulses can machine nearly any material with small kerf and little to no collateral damage to the surrounding material. The main drawback to femtosecond laser machining of ceramics is slow processing speed. In this work we report on the improvement of femtosecond laser cutting of sintered alumina substrates through optimisation of laser processing parameters. The femtosecond laser ablation thresholds for sintered alumina were measured using the diagonal scan method. Incubation effects were found to fit a defect accumulation model, with Fth,1=6.0 J/cm2 (±0.3) and Fth,∞=2.5 J/cm2 (±0.2). The focal length and depth, laser power, number of passes, and material translation speed were optimised for ablation speed and high quality. Optimal conditions of 500 mW power, 100 mm focal length, 2000 μm/s material translation speed, with 14 passes, produced complete cutting of the alumina substrate at an overall processing speed of 143 μm/s - more than 4 times faster than the maximum reported overall processing speed previously achieved by Wang et al. [1]. This process significantly increases processing speeds of alumina substrates, thereby reducing costs, making femtosecond laser machining a more viable option for industrial users.

Flash Kα radiography of laser-driven solid sphere compression for fast ignition

International Nuclear Information System (INIS)

Sawada, H.; Lee, S.; Nagatomo, H.; Arikawa, Y.; Nishimura, H.; Ueda, T.; Shigemori, K.; Fujioka, S.; Shiroto, T.; Ohnishi, N.; Sunahara, A.; Beg, F. N.; Theobald, W.; Pérez, F.; Patel, P. K.

2016-01-01

Time-resolved compression of a laser-driven solid deuterated plastic sphere with a cone was measured with flash Kα x-ray radiography. A spherically converging shockwave launched by nanosecond GEKKO XII beams was used for compression while a flash of 4.51 keV Ti Kα x-ray backlighter was produced by a high-intensity, picosecond laser LFEX (Laser for Fast ignition EXperiment) near peak compression for radiography. Areal densities of the compressed core were inferred from two-dimensional backlit x-ray images recorded with a narrow-band spherical crystal imager. The maximum areal density in the experiment was estimated to be 87 ± 26 mg/cm"2. The temporal evolution of the experimental and simulated areal densities with a 2-D radiation-hydrodynamics code is in good agreement.

Flash Kα radiography of laser-driven solid sphere compression for fast ignition

Energy Technology Data Exchange (ETDEWEB)

Sawada, H. [Department of Physics, University of Nevada Reno, Reno, Nevada 89557 (United States); Lee, S.; Nagatomo, H.; Arikawa, Y.; Nishimura, H.; Ueda, T.; Shigemori, K.; Fujioka, S. [Institute of Laser Engineering, Osaka University, Suita, Osaka (Japan); Shiroto, T.; Ohnishi, N. [Department of Aerospace Engineering, Tohoku University, Sendai, Miyagi (Japan); Sunahara, A. [Institute of Laser Technology, Nishi-ku, Osaka (Japan); Beg, F. N. [University of California San Diego, La Jolla, California 92093 (United States); Theobald, W. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States); Pérez, F. [LULI, Ecole Polytechnique, Palaiseau, Cedex (France); Patel, P. K. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

2016-06-20

Time-resolved compression of a laser-driven solid deuterated plastic sphere with a cone was measured with flash Kα x-ray radiography. A spherically converging shockwave launched by nanosecond GEKKO XII beams was used for compression while a flash of 4.51 keV Ti Kα x-ray backlighter was produced by a high-intensity, picosecond laser LFEX (Laser for Fast ignition EXperiment) near peak compression for radiography. Areal densities of the compressed core were inferred from two-dimensional backlit x-ray images recorded with a narrow-band spherical crystal imager. The maximum areal density in the experiment was estimated to be 87 ± 26 mg/cm{sup 2}. The temporal evolution of the experimental and simulated areal densities with a 2-D radiation-hydrodynamics code is in good agreement.

Loop Mirror Laser Neural Network with a Fast Liquid-Crystal Display

Science.gov (United States)

Mos, Evert C.; Schleipen, Jean J. H. B.; de Waardt, Huug; Khoe, Djan G. D.

1999-07-01

In our laser neural network (LNN) all-optical threshold action is obtained by application of controlled optical feedback to a laser diode. Here an extended experimental LNN is presented with as many as 32 neurons and 12 inputs. In the setup we use a fast liquid-crystal display to implement an optical matrix vector multiplier. This display, based on ferroelectric liquid-crystal material, enables us to present 125 training examples s to the LNN. To maximize the optical feedback efficiency of the setup, a loop mirror is introduced. We use a -rule learning algorithm to train the network to perform a number of functions toward the application area of telecommunication data switching.

Conceptual design of the fast ignition laser fusion power plant (KOYO-Fast). 6. Design of chamber and reactor system

International Nuclear Information System (INIS)

Kozaki, Yasuji; Norimatsu, Takayoshi; Furukawa, Hiroyuki; Hayashi, Takumi; Souman, Yoshihito; Nishikawa, Masabumi; Tomabechi, Ken

2007-01-01

A conceptual design of the reactor chamber system with LiPb liquid wall based on the fast ignition cone target design and the related reactor systems with exhaust system, laser beam shutter, blanket and cooling system are summarized. The multi overflow fall method was investigated as the structure of chamber and repeating 4 Hz pulse potential. The ablation depth of LiPb liquid wall was estimated and the conditions of repeat of operation were evaluated. The basic design of chamber, selection and conditions of liquid wall chamber, recycle type multi overflow fall (MOF) wall, LiPb two layers blanket structure, basic specification of reactor system, laser beam line shutter, design of chamber exhaust system, cooling system, tritium recovery system, power plant total design and arrangement of chamber and laser beam, and issues are stated. (S.Y.)

Enhancement of the Number of Fast Electrons Generated in a Laser Inverse Cone Interaction

International Nuclear Information System (INIS)

Yan-Ling, Ji; Gang, Jiang; Wei-Dong, Wu; Ji-Cheng, Zhang; Yong-Jian, Tang

2010-01-01

Enhancement of the energy-conversion efficiency from laser to target electrons is demonstrated by two-dimensional particle-in-cell simulations in a laser-inverse cone interaction. When an intense short-pulse laser illuminates the inverse cone target, the electrons at the cone end are accelerated by the ponderomotive force. Then these electrons are guided and confined to transport along the inverse cone walls by the induced electromagnetic fields. A device consisting of inverse hollow-cone and multihole array plasma is proposed in order to increase the energy-conversion efficiency from laser to electrons. Particle-in-cell simulations present that the multiholes transpiercing the cone end help to enhance the number of fast electrons and the maximum electron energy significantly. (physics of gases, plasmas, and electric discharges)

A final report to the Laboratory Directed Research and Development committee on Project 93-ERP-075: ''X-ray laser propagation and coherence: Diagnosing fast-evolving, high-density laser plasmas using X-ray lasers''

International Nuclear Information System (INIS)

Wan, A.S.; Cauble, R.; Da Silva, L.B.; Libby, S.B.; Moreno, J.C.

1996-02-01

This report summarizes the major accomplishments of this three-year Laboratory Directed Research and Development (LDRD) Exploratory Research Project (ERP) entitled ''X-ray Laser Propagation and Coherence: Diagnosing Fast-evolving, High-density Laser Plasmas Using X-ray Lasers,'' tracking code 93-ERP-075. The most significant accomplishment of this project is the demonstration of a new laser plasma diagnostic: a soft x-ray Mach-Zehnder interferometer using a neonlike yttrium x-ray laser at 155 angstrom as the probe source. Detailed comparisons of absolute two-dimensional electron density profiles obtained from soft x-ray laser interferograms and profiles obtained from radiation hydrodynamics codes, such as LASNEX, will allow us to validate and benchmark complex numerical models used to study the physics of laser-plasma interactions. Thus the development of soft x-ray interferometry technique provides a mechanism to probe the deficiencies of the numerical models and is an important tool for, the high-energy density physics and science-based stockpile stewardship programs. The authors have used the soft x-ray interferometer to study a number of high-density, fast evolving, laser-produced plasmas, such as the dynamics of exploding foils and colliding plasmas. They are pursuing the application of the soft x-ray interferometer to study ICF-relevant plasmas, such as capsules and hohlraums, on the Nova 10-beam facility. They have also studied the development of enhanced-coherence, shorter-pulse-duration, and high-brightness x-ray lasers. The utilization of improved x-ray laser sources can ultimately enable them to obtain three-dimensional holographic images of laser-produced plasmas

Carrier Frequency Offset Estimation and I/Q Imbalance Compensation for OFDM Systems

Directory of Open Access Journals (Sweden)

M. Omair Ahmad

2007-01-01

Full Text Available Two types of radio-frequency front-end imperfections, that is, carrier frequency offset and the inphase/quadrature (I/Q imbalance are considered for orthogonal frequency division multiplexing (OFDM communication systems. A preamble-assisted carrier frequency estimator is proposed along with an I/Q imbalance compensation scheme. The new frequency estimator reveals the relationship between the inphase and the quadrature components of the received preamble and extracts the frequency offset from the phase shift caused by the frequency offset and the cross-talk interference due to the I/Q imbalance. The proposed frequency estimation algorithm is fast, efficient, and robust to I/Q imbalance. An I/Q imbalance estimation/compensation algorithm is also presented by solving a least-square problem formulated using the same preamble as employed for the frequency offset estimation. The computational complexity of the I/Q estimation scheme is further reduced by using part of the short symbols with a little sacrifice in the estimation accuracy. Computer simulation and comparison with some of the existing algorithms are conducted, showing the effectiveness of the proposed method.

Self-focusing and its related interactions at very high laser intensities for fast ignition at Osaka University

International Nuclear Information System (INIS)

Tanaka, K.A.; Kodama, R.; Izumi, N.; Takahashi, K.; Heya, M.; Fujita, H.; Kato, Y.; Kitagawa, Y.; Mima, K.; Miyanaga, N.; Norimatsu, T.; Sentoku, Y.; Sunahara, A.; Takabe, H.; Yamanaka, T.; Koase, T.; Iwatani, T.; Ohtani, F.; Miyakoshi, T.; Habara, H.; Tanpo, M.; Tohyama, S.; Weber, F.A.; Barbee, T.W.; Dasilva, L.B.; Dasilva, L.B.

2000-01-01

At the Institute of Laser Engineering, various type of experiments related to fast ignition were performed with the 12-beam laser system GEKKO XII and the newly added 100 TW beams line. Using both X-ray and UV laser probes, drilling via ponderomotive laser light self-focusing was studied to show drilling well into the overdense plasma over a distance of 100 μm at a self-focused laser intensity of 10 18 W/cm 2 . This type of self-focusing accelerated electrons up to 0.1 to 1 MeV and was also applied to an imploding shell. (authors)

Conceptual design of a fast-ignition laser fusion reactor based on a dry wall chamber

International Nuclear Information System (INIS)

Ogawa, Y; Goto, T; Okano, K; Asaoka, Y; Hiwatari, R; Someya, Y

2008-01-01

The fast ignition is quite attractive for a compact laser fusion reactor, because a sufficiently high pellet gain is available with a small input energy. We designed an inertial fusion reactor based on Fast-ignition Advanced Laser fusion reactor CONcept, called FALCON-D, where a dry wall is employed for a chamber wall. A simple point model shows that the pellet gain G∼100 is available with laser energies of 350kJ for implosion, 50kJ for heating. This results in the fusion yield of 40 MJ in one shot. By increasing the repetition rate up to 30 Hz, the fusion power of 1.2 GWth becomes available. Plant system analysis shows the net electric power to be about 0.4 GWe In the fast ignition it is available to employ a low aspect ratio pellet, which is favorable for the stability during the implosion phase. Here the pellet aspect ratio is reduced to be 2 ∼ 4, and the optimization of the pulse shape for the implosion laser are carried out by using the 1-D hydrodynamic simulation code ILESTA-1D. A ferritic steel with a tungsten armour is employed for the chamber wall. The feasibility of this dry wall concept is studied from various engineering aspects such as surface melting, physical and chemical sputtering, blistering and exfoliation by helium retention, and thermo-mechanical fatigue, and it is found that blistering and exfoliation due to the helium retention and fatigue failure due to cyclic thermal load are major concerns. The cost analysis shows that the construction cost is moderate but the cost of electricity is slightly expensive

Conceptual design of a fast-ignition laser fusion reactor based on a dry wall chamber

Energy Technology Data Exchange (ETDEWEB)

Ogawa, Y [High Temperature Plasma Center, University of Tokyo, Chiba (Japan); Goto, T; Okano, K [Graduate School of Frontier Sciences, University of Tokyo, Chiba (Japan); Asaoka, Y; Hiwatari, R [Central Research Institute for Electric Power Industry, Komae, Tokyo (Japan); Someya, Y [Graduate School of Engineering, Musashi Institute of Technology, Tokyo (Japan)], E-mail: ogawa@ppl.k.u-tokyo.ac.jp

2008-05-15

The fast ignition is quite attractive for a compact laser fusion reactor, because a sufficiently high pellet gain is available with a small input energy. We designed an inertial fusion reactor based on Fast-ignition Advanced Laser fusion reactor CONcept, called FALCON-D, where a dry wall is employed for a chamber wall. A simple point model shows that the pellet gain G{approx}100 is available with laser energies of 350kJ for implosion, 50kJ for heating. This results in the fusion yield of 40 MJ in one shot. By increasing the repetition rate up to 30 Hz, the fusion power of 1.2 GWth becomes available. Plant system analysis shows the net electric power to be about 0.4 GWe In the fast ignition it is available to employ a low aspect ratio pellet, which is favorable for the stability during the implosion phase. Here the pellet aspect ratio is reduced to be 2 {approx} 4, and the optimization of the pulse shape for the implosion laser are carried out by using the 1-D hydrodynamic simulation code ILESTA-1D. A ferritic steel with a tungsten armour is employed for the chamber wall. The feasibility of this dry wall concept is studied from various engineering aspects such as surface melting, physical and chemical sputtering, blistering and exfoliation by helium retention, and thermo-mechanical fatigue, and it is found that blistering and exfoliation due to the helium retention and fatigue failure due to cyclic thermal load are major concerns. The cost analysis shows that the construction cost is moderate but the cost of electricity is slightly expensive.

Conceptual design of a fast-ignition laser fusion reactor based on a dry wall chamber

Science.gov (United States)

Ogawa, Y.; Goto, T.; Okano, K.; Asaoka, Y.; Hiwatari, R.; Someya, Y.

2008-05-01

The fast ignition is quite attractive for a compact laser fusion reactor, because a sufficiently high pellet gain is available with a small input energy. We designed an inertial fusion reactor based on Fast-ignition Advanced Laser fusion reactor CONcept, called FALCON-D, where a dry wall is employed for a chamber wall. A simple point model shows that the pellet gain G~100 is available with laser energies of 350kJ for implosion, 50kJ for heating. This results in the fusion yield of 40 MJ in one shot. By increasing the repetition rate up to 30 Hz, the fusion power of 1.2 GWth becomes available. Plant system analysis shows the net electric power to be about 0.4 GWe In the fast ignition it is available to employ a low aspect ratio pellet, which is favorable for the stability during the implosion phase. Here the pellet aspect ratio is reduced to be 2 ~ 4, and the optimization of the pulse shape for the implosion laser are carried out by using the 1-D hydrodynamic simulation code ILESTA-1D. A ferritic steel with a tungsten armour is employed for the chamber wall. The feasibility of this dry wall concept is studied from various engineering aspects such as surface melting, physical and chemical sputtering, blistering and exfoliation by helium retention, and thermo-mechanical fatigue, and it is found that blistering and exfoliation due to the helium retention and fatigue failure due to cyclic thermal load are major concerns. The cost analysis shows that the construction cost is moderate but the cost of electricity is slightly expensive.

Repetitive 1 Hz fast-heating fusion driver HAMA pumped by diode pumped solid state laser

International Nuclear Information System (INIS)

Mori, Yoshitaka; Sekine, Takashi; Komeda, Osamu

2014-01-01

We describe a repetitive fast-heating fusion driver called HAMA pumped by Diode Pumped Solid State Laser (DPSSL) to realize the counter irradiation of sequential implosion and heating laser beams. HAMA was designed to activate DPSSL for inertial confinement fusion (ICF) research and to realize a unified ICF machine for power plants. The details of a four-beam alignment scheme and the results of the counter irradiation of stainless plates are shown. (author)

Inter-comparison of laser photoacoustic spectroscopy and gas chromatography techniques for measurements of ethene in the atmosphere.

Science.gov (United States)

Kuster, William C; Harren, Frans J M; de Gouw, Joost A

2005-06-15

Laser photoacoustic spectroscopy (LPAS) is highly suitable for the detection of ethene in air due to the overlap between its strongest absorption lines and the wavelengths accessible by high-powered CO2 lasers. Here, we test the ability of LPAS to measure ethene in ambient air by comparing the measurements in urban air with those from a gas chromatography flame-ionization detection (GC-FID) instrument. Over the course of several days, we obtained quantitative agreement between the two measurements. Over this period, the LPAS instrument had a positive offset of 330 +/- 140 pptv (parts-per-trillion by volume) relative to the GC-FID instrument, possibly caused by interference from other species. The detection limit of the LPAS instrument is currently estimated around 1 ppbv and is limited by this offset and the statistical noise in the data. We conclude that LPAS has the potential to provide fast-response measurements of ethene in the atmosphere, with significant advantages over existing techniques when measuring from moving platforms and in the vicinity of emission sources.

Laser-driven ablation through fast electrons in PALS experiment at the laser radiation intensity of 1–50 PW/cm2

Czech Academy of Sciences Publication Activity Database

Gus’kov, S.Yu.; Demchenko, N. N.; Kasperczuk, A.; Pisarczyk, T.; Kalinowska, Z.; Chodukowski, T.; Renner, Oldřich; Šmíd, Michal; Krouský, Eduard; Pfeifer, Miroslav; Skála, Jiří; Ullschmied, Jiří; Pisarczyk, P.

2014-01-01

Roč. 32, č. 1 (2014), s. 177-195 ISSN 0263-0346 R&D Projects: GA MŠk LM2010014; GA MŠk EE2.3.20.0279 EU Projects: European Commission(XE) 284464 - LASERLAB-EUROPE Grant - others:AVČR(CZ) M100101208; LaserZdroj (OP VK 3)(XE) CZ.1.07/2.3.00/20.0279 Institutional support: RVO:68378271 ; RVO:61389021 Keywords : inertial confinement fusion * shock ignition * laser-produced plasma * three-frame interferometry * X-ray spectroscopy * fast electron generation Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.295, year: 2014

Carbon offsetting: sustaining consumption?

OpenAIRE

Heather Lovell; Harriet Bulkeley; Diana Liverman

2009-01-01

In this paper we examine how theories of sustainable and ethical consumption help us to understand a new, rapidly expanding type of consumer product designed to mitigate climate change: carbon offsets. The voluntary carbon offset market grew by 200% between 2005 and 2006, and there are now over 150 retailers of voluntary carbon offsets worldwide. Our analysis concentrates on the production and consumption of carbon offsets, drawing on ideas from governmentality and political ecology about how...

The effect of offset cues on saccade programming and covert attention.

Science.gov (United States)

Smith, Daniel T; Casteau, Soazig

2018-02-01

Salient peripheral events trigger fast, "exogenous" covert orienting. The influential premotor theory of attention argues that covert orienting of attention depends upon planned but unexecuted eye-movements. One problem with this theory is that salient peripheral events, such as offsets, appear to summon attention when used to measure covert attention (e.g., the Posner cueing task) but appear not to elicit oculomotor preparation in tasks that require overt orienting (e.g., the remote distractor paradigm). Here, we examined the effects of peripheral offsets on covert attention and saccade preparation. Experiment 1 suggested that transient offsets summoned attention in a manual detection task without triggering motor preparation planning in a saccadic localisation task, although there were a high proportion of saccadic capture errors on "no-target" trials, where a cue was presented but no target appeared. In Experiment 2, "no-target" trials were removed. Here, transient offsets produced both attentional facilitation and faster saccadic responses on valid cue trials. A third experiment showed that the permanent disappearance of an object also elicited attentional facilitation and faster saccadic reaction times. These experiments demonstrate that offsets trigger both saccade programming and covert attentional orienting, consistent with the idea that exogenous, covert orienting is tightly coupled with oculomotor activation. The finding that no-go trials attenuates oculomotor priming effects offers a way to reconcile the current findings with previous claims of a dissociation between covert attention and oculomotor control in paradigms that utilise a high proportion of catch trials.

Fast pulsing dynamics of a vertical-cavity surface-emitting laser operating in the low-frequency fluctuation regime

International Nuclear Information System (INIS)

Sciamanna, M.; Rogister, F.; Megret, P.; Blondel, M.; Masoller, C.; Abraham, N. B.

2003-01-01

We analyze the dynamics of a vertical-cavity surface-emitting laser with optical feedback operating in the low-frequency fluctuation regime. By focusing on the fast pulsing dynamics, we show that the two linearly polarized modes of the laser exhibit two qualitatively different behaviors: they emit pulses in phase just after a power dropout and they emit pulses out of phase after the recovery process of the output power. As a consequence, two distinct statistical distributions of the fast pulsating total intensity are observed, either monotonically decaying from the noise level or peaked around the mean intensity value. We further show that gain self-saturation of the lasing transition strongly modifies the shape of the intensity distribution

A vision-based system for fast and accurate laser scanning in robot-assisted phonomicrosurgery.

Science.gov (United States)

Dagnino, Giulio; Mattos, Leonardo S; Caldwell, Darwin G

2015-02-01

Surgical quality in phonomicrosurgery can be improved by open-loop laser control (e.g., high-speed scanning capabilities) with a robust and accurate closed-loop visual servoing systems. A new vision-based system for laser scanning control during robot-assisted phonomicrosurgery was developed and tested. Laser scanning was accomplished with a dual control strategy, which adds a vision-based trajectory correction phase to a fast open-loop laser controller. The system is designed to eliminate open-loop aiming errors caused by system calibration limitations and by the unpredictable topology of real targets. Evaluation of the new system was performed using CO(2) laser cutting trials on artificial targets and ex-vivo tissue. This system produced accuracy values corresponding to pixel resolution even when smoke created by the laser-target interaction clutters the camera view. In realistic test scenarios, trajectory following RMS errors were reduced by almost 80 % with respect to open-loop system performances, reaching mean error values around 30 μ m and maximum observed errors in the order of 60 μ m. A new vision-based laser microsurgical control system was shown to be effective and promising with significant positive potential impact on the safety and quality of laser microsurgeries.

Mono-Exponential Fitting in T2-Relaxometry: Relevance of Offset and First Echo.

Directory of Open Access Journals (Sweden)

David Milford

Full Text Available T2 relaxometry has become an important tool in quantitative MRI. Little focus has been put on the effect of the refocusing flip angle upon the offset parameter, which was introduced to account for a signal floor due to noise or to long T2 components. The aim of this study was to show that B1 imperfections contribute significantly to the offset. We further introduce a simple method to reduce the systematic error in T2 by discarding the first echo and using the offset fitting approach.Signal curves of T2 relaxometry were simulated based on extended phase graph theory and evaluated for 4 different methods (inclusion and exclusion of the first echo, while fitting with and without the offset. We further performed T2 relaxometry in a phantom at 9.4T magnetic resonance imaging scanner and used the same methods for post-processing as in the extended phase graph simulated data. Single spin echo sequences were used to determine the correct T2 time.The simulation data showed that the systematic error in T2 and the offset depends on the refocusing pulse, the echo spacing and the echo train length. The systematic error could be reduced by discarding the first echo. Further reduction of the systematic T2 error was reached by using the offset as fitting parameter. The phantom experiments confirmed these findings.The fitted offset parameter in T2 relaxometry is influenced by imperfect refocusing pulses. Using the offset as a fitting parameter and discarding the first echo is a fast and easy method to minimize the error in T2, particularly for low to intermediate echo train length.

Energy distribution of the fast electron from Cu and CH targets irradiated with fs-laser pulses

International Nuclear Information System (INIS)

Cai Dafeng; Gu Yuqiu; Zheng Zhijian; Zhou Weimin; Jiao Chunye

2014-01-01

In order to investigate the effect of target's material on fast electron energy distribution, the energy distribution of fast electrons from the front and the rear of Cu and CH targets have been measured during the interaction of femtosecond laser-foil targets. The results show that the fast electron spectrums from the front of Cu and CH targets are similar, which show energy distribution of fast electrons depends very little on material of targets. The fast electron spectrums from the rear of Cu and CH targets are obviously dissimilar, which indicate a mighty effect of target material on fast electron transport. The fast electron spectrums from the Cu target is 'soften', which is due to electron recirculation and self-magnetic field produced by electrons transported in the target. The fast electron spectrums from the CH target is a Maxwellian distribution, which is due to collision effect when electrons transport in the target. (authors)

Petawatt laser system for the fast ignition studies at ILE, Osaka University

International Nuclear Information System (INIS)

Izawa, Y.

2002-01-01

We have developed a PW Nd:glass laser system, which can deliver 1 PW output with 500 J in 0.5 ps, to study a fast ignitor concept in laser fusion. In the front end of this system, the optical parametric chirped-pulse amplifier (OPCPA) was introduced. The OPCPA solves several problems arising in an existing Ti:sapphire regenerative amplifier, such as low single-pass gain, high prepulse and output fluctuation. A booster amplifier is a Cassegrain-type three pass disk system having a 350 mm clear aperture, which generated 1.1 kJ output energy with the spectral width of 3.7 nm corresponding to 0.5 ps in Fourier transform limited pulse. The spatial phase aberration mainly caused in the booster amplifier is corrected using a deformable mirror. The laser pulse is compressed by a pair of 1-m diffraction gratings and focused by a parabolic mirror. The timing jitter between PW laser and GEKKO XII is less than 10 ps, which was attained by injecting a weak pulse splitted out from the front end into the preamplifier of GEKKO XII. (author)

Relativistic self focussing of laser beams at fast ignitor inertial fusion with volume ignition

International Nuclear Information System (INIS)

Osman, F.; Castillo, R.; Hora, H.

1999-01-01

The alternative to the magnetic confinement fusion is inertial fusion energy mostly using lasers as drivers for compression and heating of pellets with deuterium and tritium fuel. Following the present technology of lasers with pulses of some megajoules energy and nanosecond duration, a power station for very low cost energy production (and without the problems of well erosion of magnetic confinement) could be available within 15 to 20 years. For the pellet compression, the scheme of spark ignition was mostly applied but its numerous problems with asymmetries and instabilities may be overcome by the alternative scheme of high gain volume ignition. This is a well established option of inertial fusion energy with lasers where a large range of possible later improvements is implied with respect to laser technology or higher plasma compression leading to energy production of perhaps five times below the present lowest level cost from fission reactors. A further improvement may be possible by the recent development of lasers with picosecond pulse duration using the fast igniter scheme which may reach even higher fusion gains with laser pulse energies of some 100 kilojoules

Great Apes and Biodiversity Offset Projects in Africa: The Case for National Offset Strategies

Science.gov (United States)

Kormos, Rebecca; Kormos, Cyril F.; Humle, Tatyana; Lanjouw, Annette; Rainer, Helga; Victurine, Ray; Mittermeier, Russell A.; Diallo, Mamadou S.; Rylands, Anthony B.; Williamson, Elizabeth A.

2014-01-01

The development and private sectors are increasingly considering “biodiversity offsets” as a strategy to compensate for their negative impacts on biodiversity, including impacts on great apes and their habitats in Africa. In the absence of national offset policies in sub-Saharan Africa, offset design and implementation are guided by company internal standards, lending bank standards or international best practice principles. We examine four projects in Africa that are seeking to compensate for their negative impacts on great ape populations. Our assessment of these projects reveals that not all apply or implement best practices, and that there is little standardization in the methods used to measure losses and gains in species numbers. Even if they were to follow currently accepted best-practice principles, we find that these actions may still fail to contribute to conservation objectives over the long term. We advocate for an alternative approach in which biodiversity offset and compensation projects are designed and implemented as part of a National Offset Strategy that (1) takes into account the cumulative impacts of development in individual countries, (2) identifies priority offset sites, (3) promotes aggregated offsets, and (4) integrates biodiversity offset and compensation projects with national biodiversity conservation objectives. We also propose supplementary principles necessary for biodiversity offsets to contribute to great ape conservation in Africa. Caution should still be exercised, however, with regard to offsets until further field-based evidence of their effectiveness is available. PMID:25372894

Application of ultra-fast high-resolution gated-image intensifiers to laser fusion studies

International Nuclear Information System (INIS)

Lieber, A.J.; Benjamin, R.F.; Sutphin, H.D.; McCall, G.H.

1975-01-01

Gated-image intensifiers for fast framing have found high utility in laser-target interaction studies. X-ray pinhole camera photographs which can record asymmetries of laser-target interactions have been instrumental in further system design. High-resolution high-speed x-ray images of laser irradiated targets are formed using pinhole optics and electronically amplified by proximity focused channelplate intensifiers before being recorded on film. Spectral resolution is obtained by filtering. In these applications shutter duration is determined by source duration. Electronic gating serves to reduce background thereby enhancing signal-to-noise ratio. Cameras are used to view the self light of the interaction but may also be used for shadowgraphs. Sources for shadowgraphs may be sequenced to obtain a series of pictures with effective rates of 10 10 frame/s. Multiple aperatures have been used to obtain stereo x-ray views, yielding three dimensional information about the interactions. (author)

Analysis of two colliding laser-produced plasmas by emission spectroscopy and fast photography

Energy Technology Data Exchange (ETDEWEB)

Sanchez-Ake, C., E-mail: citlali.sanchez@ccadet.unam.m [Centro de Ciencias Aplicadas y Desarrollo Tecnologico, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-186, Mexico D.F., C.P. 04510 (Mexico); Mustri-Trejo, D. [Centro de Ciencias Aplicadas y Desarrollo Tecnologico, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-186, Mexico D.F., C.P. 04510 (Mexico); Garcia-Fernandez, T. [Universidad Autonoma de la Ciudad de Mexico, Prolongacion San Isidro 151, Col. San Lorenzo Tezonco, Mexico DF, C.P. 09790 (Mexico); Villagran-Muniz, M. [Centro de Ciencias Aplicadas y Desarrollo Tecnologico, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-186, Mexico D.F., C.P. 04510 (Mexico)

2010-05-15

In this work two colliding laser-induced plasmas (LIP) on Cu and C were studied by means of time resolved emission spectroscopy and fast photography. The experiments were performed using two opposing parallel targets of Cu and C in vacuum, ablated with two synchronized ns lasers. The results showed an increased emission intensity from copper ions Cu II (368.65, 490.97, 493.16, 495.37 and 630.10 nm) and Cu III (374.47 and 379.08 nm) due to the ionization that occurs during collisions of Cu and C species. It was found that the optimum delay between pulses, which yields the maximum emission enhancement of Cu ions, depends on the sampling distance. On the other hand, the emission intensity of C lines, C II (426.70 nm), C III (406.99 and 464.74 nm) and C IV (465.83 nm), decreased and the formation of C{sub 2} molecules was observed. A comparison between the temporal evolution of the individual plasmas and their collision performed by combining imaging and the time resolved emission diagnostics, revealed an increase of the electron temperature and electron density and the splitting of the plume into slow and fast components.

THE ODD OFFSET BETWEEN THE GALACTIC DISK AND ITS BAR IN NGC 3906

Energy Technology Data Exchange (ETDEWEB)

Swardt, Bonita de [South African Astronomical Observatory, Observatory, 7935 Cape Town (South Africa); Sheth, Kartik; Kim, Taehyun; Muñoz-Mateos, Juan-Carlos [National Radio Astronomy Observatory/NAASC, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Stephen Pardy; Elena D’ Onghia; Eric Wilcots [Department of Astronomy, University of Wisconsin, 475 North Charter Street, Madison, WI 53706 (United States); Hinz, Joannah [MMTO, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Regan, Michael W. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Athanassoula, E.; Bosma, Albert [Aix Marseille Université, CNRS, LAM (Laboratoire d’Astrophysique de Marseille) UMR 7326, F-13388 Marseille (France); Buta, Ronald J. [Department of Physics and Astronomy, University of Alabama, Box 870324, Tuscaloosa, AL 35487 (United States); Cisternas, Mauricio; Erroz-Ferrer, Santiago [Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife (Spain); Comerón, Sébastien [Division of Astronomy, Department of Physical Sciences, University of Oulu, Oulu, FI-90014 (Finland); Gadotti, Dimitri A. [European Southern Observatory, Casilla 19001, Santiago 19 (Chile); Paz, Armando Gil de [Departamento de Astrofísica, Universidad Complutense de Madrid, Madrid E-28040 (Spain); Jarrett, Thomas H. [Astronomy Department, University of Cape Town, Rondebosch 7701 (South Africa); Elmegreen, Bruce G. [IBM Research Division, T.J. Watson Research Center, Yorktown Hts., NY 10598 (United States); Ho, Luis C. [The Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); and others

2015-07-20

We use mid-infrared 3.6 and 4.5 μm imaging of NGC 3906 from the Spitzer Survey of Stellar Structure in Galaxies (S{sup 4}G) to understand the nature of an unusual offset between its stellar bar and the photometric center of an otherwise regular, circular outer stellar disk. We measure an offset of ∼910 pc between the center of the stellar bar and photometric center of the stellar disk; the bar center coincides with the kinematic center of the disk determined from previous HI observations. Although the undisturbed shape of the disk suggests that NGC 3906 has not undergone a significant merger event in its recent history, the most plausible explanation for the observed offset is an interaction. Given the relatively isolated nature of NGC 3906 this interaction could be with dark matter substructure in the galaxy's halo or from a recent interaction with a fast moving neighbor that remains to be identified. Simulations aimed at reproducing the observed offset between the stellar bar/kinematic center of the system and the photometric center of the disk are necessary to confirm this hypothesis and constrain the interaction history of the galaxy.

Searching for Fast Radio Bursts with the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO)

Science.gov (United States)

Fisher, Ryan Patrick; Hughey, Brennan; Howell, Eric; LIGO Collaboration

2018-01-01

Although Fast Radio Bursts (FRB) are being detected with increasing frequency, their progenitor systems are still mostly a mystery. We present the plan to conduct targeted searches for gravitational-wave counterparts to these FRB events in the data from the first and second observing runs of the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO).

Study of Nuclear Moments and Mean Square Charge Radii by Collinear Fast-Beam Laser Spectroscopy

CERN Multimedia

2002-01-01

The collinear fast-beam laser technique is used to measure atomic hyperfine structures and isotope shifts of unstable nuclides produced at ISOLDE. This gives access to basic nuclear ground-state and isomeric-state properties such as spins, magnetic dipole and electric quadrupole moments, and the variation of the nuclear mean square charge radius within a sequence of isotopes. \\\\ \\\\ Among the various techniques used for this purpose, the present approach is of greatest versatility, due to the direct use of the beams from the isotope separator. Their phase-space properties are exploited to achieve high sensitivity and resolution. The optical spectra of neutral atoms are made accessible by converting the ion beams into fast atomic beams. This is accomplished in the charge-exchange cell which is kept at variable potential ($\\pm$10~kV) for Doppler-tuning of the effective laser wavelength. The basic optical resolution of 10$^{-8}$ requires a 10$^{-5}$ stability of the 60~kV main acceleration voltage and low energy ...

Proton- and x-ray beams generated by ultra-fast CO2 lasers for medical applications

Science.gov (United States)

Pogorelsky, Igor; Polyanskiy, Mikhail; Yakimenko, Vitaly; Ben-Zvi, Ilan; Shkolnikov, Peter; Najmudin, Zulfikar; Palmer, Charlotte A. J.; Dover, Nicholas P.; Oliva, Piernicola; Carpinelli, Massimo

2011-05-01

Recent progress in using picosecond CO2 lasers for Thomson scattering and ion-acceleration experiments underlines their potentials for enabling secondary radiation- and particle- sources. These experiments capitalize on certain advantages of long-wavelength CO2 lasers, such as higher number of photons per energy unit, and favorable scaling of the electrons' ponderomotive energy and critical plasma density. The high-flux x-ray bursts produced by Thomson scattering of the CO2 laser off a counter-propagating electron beam enabled high-contrast, time-resolved imaging of biological objects in the picosecond time frame. In different experiments, the laser, focused on a hydrogen jet, generated monoenergetic proton beams via the radiation-pressure mechanism. The strong power-scaling of this regime promises realization of proton beams suitable for laser-driven proton cancer therapy after upgrading the CO2 laser to sub-PW peak power. This planned improvement includes optimizing the 10-μm ultra-short pulse generation, assuring higher amplification in the CO2 gas under combined isotopic- and power-broadening effects, and shortening the postamplification pulse to a few laser cycles (150-200 fs) via chirping and compression. These developments will move us closer to practical applications of ultra-fast CO2 lasers in medicine and other areas.

The evolution of two-dimensional effects in fast electron transport from high intensity laser plasma interactions

International Nuclear Information System (INIS)

Amiranoff, F.; Eidmann, K.; Sigel, R.; Fedosejevs, R.; Maaswinkel, A.; Teng, Y.L.; Kilkenny, J.D.; Hares, J.D.; Bradley, D.K.; MacGowan, B.J.

1982-04-01

Measurements of local and remote energy deposition by fast electrons have been made in 1.3 μm and 1.05 μm laser irradiation experiments with plane targets and various pulse lengths. From optical and X-ray streak photography and spatially resolved Kα yield measurements it is found that up to 30% of the absorbed laser energy spreads laterally to distances of several millimeters from the focal spot with a spreading velocity in excess of 10 8 cm sec -1 . (orig.)

Photoconductive Detectors with Fast Temporal Response for Laser Produced Plasma Experiments

International Nuclear Information System (INIS)

M. J. May; C. Halvorson; T. Perry; F. Weber; P. Young; C. Silbernagel

2008-01-01

Processes during laser plasma experiments typically have time scales that are less than 100 ps. The measurement of these processes requires X-ray detectors with fast temporal resolution. We have measured the temporal responses and linearity of several different X-ray sensitive Photoconductive Detectors (PCDs). The active elements of the detectors investigated include both diamond (natural and synthetic) and GaAs crystals. The typical time responses of the GaAs PCDs are approximately 60 ps, respectively. Some characterizations using X-ray light from a synchrotron light source are presented

Microstructure and lubricating property of ultra-fast laser pulse textured silicon carbide seals

Science.gov (United States)

Chen, Chien-Yu; Chung, Chung-Jen; Wu, Bo-Hsiung; Li, Wang-Long; Chien, Chih-Wei; Wu, Ping-Han; Cheng, Chung-Wei

2012-05-01

Most previous studies have employed surface patterning to improve the performance of lubrication systems. However, few have experimentally analyzed improved effects on friction reduction in SiC mechanical seals by ultra-fast laser pulse texturing. This work applies surface texturing on a non-contact mechanical seal and analyzes the characteristics of the resultant surface morphology. A femtosecond laser system is employed to fabricate micro/nanostructures on the SiC mechanical seal, and generates microscale-depth stripes and induces nanostructures on the seal surface. This work examines the morphology and cross section of the SiC nanostructures that correspond to the different scanning speeds of the laser pulse. Results show that varying the scanning speed enables the application of nanostructures of different amplitudes and widths on the surface of the seal. The friction coefficient of the introduced SiC full-textured seal is about 20% smaller than that of a conventional SiC mechanical seal. Hence, femtosecond laser texturing is effective and enables direct fabrication of the surface micro/nanostructures of SiC seals. This technique also serves as a potential approach to lubricating applications.

Microstructure and lubricating property of ultra-fast laser pulse textured silicon carbide seals

Energy Technology Data Exchange (ETDEWEB)

Chen, Chien-Yu.; Li, Wang-Long [National Cheng Kung University, Department of Materials Science and Engineering, Tainan, Taiwan (China); Chung, Chung-Jen; Wu, Bo-Hsiung [National Cheng Kung University, Center for Micro/Nano Science and Technology, Tainan, Taiwan (China); Chien, Chih-Wei; Wu, Ping-Han; Cheng, Chung-Wei [ITRI South, Industrial Technology, Research Institute, Laser Application Technology Center, Tainan, Taiwan (China)

2012-05-15

Most previous studies have employed surface patterning to improve the performance of lubrication systems. However, few have experimentally analyzed improved effects on friction reduction in SiC mechanical seals by ultra-fast laser pulse texturing. This work applies surface texturing on a non-contact mechanical seal and analyzes the characteristics of the resultant surface morphology. A femtosecond laser system is employed to fabricate micro/nanostructures on the SiC mechanical seal, and generates microscale-depth stripes and induces nanostructures on the seal surface. This work examines the morphology and cross section of the SiC nanostructures that correspond to the different scanning speeds of the laser pulse. Results show that varying the scanning speed enables the application of nanostructures of different amplitudes and widths on the surface of the seal. The friction coefficient of the introduced SiC full-textured seal is about 20% smaller than that of a conventional SiC mechanical seal. Hence, femtosecond laser texturing is effective and enables direct fabrication of the surface micro/nanostructures of SiC seals. This technique also serves as a potential approach to lubricating applications. (orig.)

Ellipticity and the offset angle of high harmonics generated by homonuclear diatomic molecules

International Nuclear Information System (INIS)

Odzak, S; Milosevic, D B

2011-01-01

In our recent paper (2010 Phys. Rev. A 82 023412) we introduced a theory of high-order harmonic generation by diatomic molecules exposed to an elliptically polarized laser field and have shown that the nth harmonic emission rate has contributions of the components of the T-matrix element in the direction of the laser-field polarization and in the direction perpendicular to it. Using both components of the T-matrix element we now develop a theoretical approach for calculating ellipticity and the offset angle of high harmonics. We show that the emitted harmonics generated by aligned molecules are elliptically polarized even if the applied field is linearly polarized. Using examples of N 2 , O 2 and Ar 2 molecules we show the existence of extrema and sudden changes of the harmonic ellipticity and the offset angle for particular molecular alignment and explain them by the destructive two-centre interference. Taking into account that the aligned molecules are an anisotropic medium for high harmonic generation, we introduce elliptic dichroism as a measure of this anisotropy, for both components of the T-matrix element. We propose that the measurement of the elliptic dichroism may reveal further information about the molecular structure.

The voluntary offset - approaches and limitations

International Nuclear Information System (INIS)

2012-06-01

After having briefly presented the voluntary offset mechanism which aims at funding a project of reduction or capture of greenhouse gas emissions, this document describes the approach to be followed to adopt this voluntary offset, for individuals as well as for companies, communities or event organisations. It describes other important context issues (projects developed under the voluntary offset, actors of the voluntary offsetting market, market status, offset labels), and how to proceed in practice (definition of objectives and expectations, search for needed requirements, to ensure the meeting of requirements with respect to expectations). It addresses the case of voluntary offset in France (difficult implantation, possible solutions)

Ultrafast, high repetition rate, ultraviolet, fiber-laser-based source: application towards Yb+ fast quantum-logic.

Science.gov (United States)

Hussain, Mahmood Irtiza; Petrasiunas, Matthew Joseph; Bentley, Christopher D B; Taylor, Richard L; Carvalho, André R R; Hope, Joseph J; Streed, Erik W; Lobino, Mirko; Kielpinski, David

2016-07-25

Trapped ions are one of the most promising approaches for the realization of a universal quantum computer. Faster quantum logic gates could dramatically improve the performance of trapped-ion quantum computers, and require the development of suitable high repetition rate pulsed lasers. Here we report on a robust frequency upconverted fiber laser based source, able to deliver 2.5 ps ultraviolet (UV) pulses at a stabilized repetition rate of 300.00000 MHz with an average power of 190 mW. The laser wavelength is resonant with the strong transition in Ytterbium (Yb+) at 369.53 nm and its repetition rate can be scaled up using high harmonic mode locking. We show that our source can produce arbitrary pulse patterns using a programmable pulse pattern generator and fast modulating components. Finally, simulations demonstrate that our laser is capable of performing resonant, temperature-insensitive, two-qubit quantum logic gates on trapped Yb+ ions faster than the trap period and with fidelity above 99%.

A GPS Satellite Clock Offset Prediction Method Based on Fitting Clock Offset Rates Data

Directory of Open Access Journals (Sweden)

WANG Fuhong

2016-12-01

Full Text Available It is proposed that a satellite atomic clock offset prediction method based on fitting and modeling clock offset rates data. This method builds quadratic model or linear model combined with periodic terms to fit the time series of clock offset rates, and computes the model coefficients of trend with the best estimation. The clock offset precisely estimated at the initial prediction epoch is directly adopted to calculate the model coefficient of constant. The clock offsets in the rapid ephemeris (IGR provided by IGS are used as modeling data sets to perform certain experiments for different types of GPS satellite clocks. The results show that the clock prediction accuracies of the proposed method for 3, 6, 12 and 24 h achieve 0.43, 0.58, 0.90 and 1.47 ns respectively, which outperform the traditional prediction method based on fitting original clock offsets by 69.3%, 61.8%, 50.5% and 37.2%. Compared with the IGU real-time clock products provided by IGS, the prediction accuracies of the new method have improved about 15.7%, 23.7%, 27.4% and 34.4% respectively.

Measurement of ZnO/Al2O3 Heterojunction Band Offsets by in situ X-Ray Photoelectron Spectroscopy

International Nuclear Information System (INIS)

Lei Hong-Wen; Zhang Hong; Wang Xue-Min; Zhao Yan; Yan Da-Wei; Jiang Zhong-Qian; Yao Gang; Zeng Ti-Xian; Wu Wei-Dong

2013-01-01

ZnO films are grown on c-sapphire substrates by laser molecular beam epitaxy. The band offsets of the ZnO/Al 2 O 3 heterojunction are studied by in situ x-ray photoelectron spectroscopy. The valence band of Al 2 O 3 is found to be 3.59±0.05eV below that of ZnO. Together with the resulting conduction band offset of 2.04±0.05eV, this indicates that a type-I staggered band line exists at the ZnO/Al 2 O 3 heterojunction

7 CFR 400.129 - Salary offset.

Science.gov (United States)

2010-01-01

... 7 Agriculture 6 2010-01-01 2010-01-01 false Salary offset. 400.129 Section 400.129 Agriculture... Years § 400.129 Salary offset. (a) Debt collection by salary offset is feasible if: the cost to the Government of collection by salary offset does not exceed the amount of the debt; there are no legal...

Improving beam spectral and spatial quality by double-foil target in laser ion acceleration for ion-driven fast ignition

International Nuclear Information System (INIS)

Huang, Chenkun; Albright, Brian J.

2010-01-01

Mid-Z ion driven fast ignition inertial fusion requires ion beams of 100s of MeV energy and < 10% energy spread. An overdense run-scale foil target driven by a high intensity laser pulse can produce an ion beam that has attractive properties for this application. The Break Out Afterburner (BOA) is one laser-ion acceleration mechanism proposed to generate such beams, however the late stages of the BOA tend to produce too large of an energy spread. The spectral and spatial qualities of the beam quickly evolve as the ion beam and co-moving electrons continue to interact with the laser. Here we show how use of a second target foil placed behind a nm-scale foil can substantially reduce the temperature of the co-moving electrons and improve the ion beam energy spread. Particle-In-Cell simulations reveal the dynamics of the ion beam under control. Optimal conditions for improving the spectral and spatial spread of the ion beam is explored for current laser and target parameters, leading to generation of ion beams of energy 100s of MeV and 6% energy spread, a vital step for realizing ion-driven fast ignition.

Fast ignition realization experiment with high-contrast kilo-joule peta-watt LFEX laser and strong external magnetic field

Science.gov (United States)

Fujioka, Shinsuke; Arikawa, Yasunobu; Kojima, Sadaoki; Johzaki, Tomoyuki; Nagatomo, Hideo; Sawada, Hiroshi; Lee, Seung Ho; Shiroto, Takashi; Ohnishi, Naofumi; Morace, Alessio; Vaisseau, Xavier; Sakata, Shohei; Abe, Yuki; Matsuo, Kazuki; Farley Law, King Fai; Tosaki, Shota; Yogo, Akifumi; Shigemori, Keisuke; Hironaka, Yoichiro; Zhang, Zhe; Sunahara, Atsushi; Ozaki, Tetsuo; Sakagami, Hitoshi; Mima, Kunioki; Fujimoto, Yasushi; Yamanoi, Kohei; Norimatsu, Takayoshi; Tokita, Shigeki; Nakata, Yoshiki; Kawanaka, Junji; Jitsuno, Takahisa; Miyanaga, Noriaki; Nakai, Mitsuo; Nishimura, Hiroaki; Shiraga, Hiroyuki; Kondo, Kotaro; Bailly-Grandvaux, Mathieu; Bellei, Claudio; Santos, João Jorge; Azechi, Hiroshi

2016-05-01

A petawatt laser for fast ignition experiments (LFEX) laser system [N. Miyanaga et al., J. Phys. IV France 133, 81 (2006)], which is currently capable of delivering 2 kJ in a 1.5 ps pulse using 4 laser beams, has been constructed beside the GEKKO-XII laser facility for demonstrating efficient fast heating of a dense plasma up to the ignition temperature under the auspices of the Fast Ignition Realization EXperiment (FIREX) project [H. Azechi et al., Nucl. Fusion 49, 104024 (2009)]. In the FIREX experiment, a cone is attached to a spherical target containing a fuel to prevent a corona plasma from entering the path of the intense heating LFEX laser beams. The LFEX laser beams are focused at the tip of the cone to generate a relativistic electron beam (REB), which heats a dense fuel core generated by compression of a spherical deuterized plastic target induced by the GEKKO-XII laser beams. Recent studies indicate that the current heating efficiency is only 0.4%, and three requirements to achieve higher efficiency of the fast ignition (FI) scheme with the current GEKKO and LFEX systems have been identified: (i) reduction of the high energy tail of the REB; (ii) formation of a fuel core with high areal density using a limited number (twelve) of GEKKO-XII laser beams as well as a limited energy (4 kJ of 0.53-μm light in a 1.3 ns pulse); (iii) guiding and focusing of the REB to the fuel core. Laser-plasma interactions in a long-scale plasma generate electrons that are too energetic to efficiently heat the fuel core. Three actions were taken to meet the first requirement. First, the intensity contrast of the foot pulses to the main pulses of the LFEX was improved to >109. Second, a 5.5-mm-long cone was introduced to reduce pre-heating of the inner cone wall caused by illumination of the unconverted 1.053-μm light of implosion beam (GEKKO-XII). Third, the outside of the cone wall was coated with a 40-μm plastic layer to protect it from the pressure caused by imploding

Laser fusion research with GEKKO XII and PW laser system at Osaka

International Nuclear Information System (INIS)

Izawa, Y.; Mima, K.; Azechi, H.; Fujioka, S.; Fujita, H.; Fujimoto, Y.; Jitsuno, T.; Johzaki, Y.; Kitagawa, Y.; Kodama, R.; Kondo, K.; Miyanaga, N.; Nagai, K.; Nagatomo, H.; Nakai, M.; Nishihara, K.; Nishimura, H.; Norimatsu, T.; Shiraga, H.; Shigemori, K.; Sunahara, A.; Tanaka, K.A.; Tsubakimoto, K.; Nakao, Y.; Norreys, P.; Sakagami, H.

2005-01-01

Fast heating of the compressed core plasma up to 500eV has been successfully demonstrated by injecting a 400J/0.6ps PW laser into a compressed CD shell through a hollow gold cone. According to this result, we started the FIREX (Fast Ignition Realization Experiment) project toward demonstrating the ignition of the highly compressed DT fuel by the high energy PW laser heating. A new heating laser LFEX (Laser for Fast Ignition Experiment) is under construction. In this paper the progresses in the experimental studies on scientific issues related to fast ignition and the integrated code development toward the FIREX will be reported. Research results on implosion hydrodynamics, Rayleigh-Taylor instability growth and a new stabilization mechanism are also reported. (author)

Atomic spectroscopy with diode lasers

International Nuclear Information System (INIS)

Tino, G.M.

1994-01-01

Some applications of semiconductor diode lasers in atomic spectroscopy are discussed by describing different experiments performed with lasers emitting in the visible and in the near-infrared region. I illustrate the results obtained in the investigation of near-infrared transitions of atomic oxygen and of the visible intercombination line of strontium. I also describe how two offset-frequency-locked diode lasers can be used to excite velocity selective Raman transitions in Cs. I discuss the spectral resolution, the accuracy of frequency measurements, and the detection sensitivity achievable with diode lasers. (orig.)

Fast ignition realization experiment with high-contrast kilo-joule peta-watt LFEX laser and strong external magnetic field

Energy Technology Data Exchange (ETDEWEB)

Fujioka, Shinsuke, E-mail: sfujioka@ile.osaka-u.ac.jp; Arikawa, Yasunobu; Kojima, Sadaoki; Nagatomo, Hideo; Lee, Seung Ho; Morace, Alessio; Vaisseau, Xavier; Sakata, Shohei; Abe, Yuki; Matsuo, Kazuki; Farley Law, King Fai; Tosaki, Shota; Yogo, Akifumi; Shigemori, Keisuke; Hironaka, Yoichiro; Fujimoto, Yasushi; Yamanoi, Kohei; Norimatsu, Takayoshi; Tokita, Shigeki; Nakata, Yoshiki [Institute of Laser Engineering, Osaka University, 2-6 Yamada-Oka, Suita, Osaka 565-0871 Japan (Japan); and others

2016-05-15

A petawatt laser for fast ignition experiments (LFEX) laser system [N. Miyanaga et al., J. Phys. IV France 133, 81 (2006)], which is currently capable of delivering 2 kJ in a 1.5 ps pulse using 4 laser beams, has been constructed beside the GEKKO-XII laser facility for demonstrating efficient fast heating of a dense plasma up to the ignition temperature under the auspices of the Fast Ignition Realization EXperiment (FIREX) project [H. Azechi et al., Nucl. Fusion 49, 104024 (2009)]. In the FIREX experiment, a cone is attached to a spherical target containing a fuel to prevent a corona plasma from entering the path of the intense heating LFEX laser beams. The LFEX laser beams are focused at the tip of the cone to generate a relativistic electron beam (REB), which heats a dense fuel core generated by compression of a spherical deuterized plastic target induced by the GEKKO-XII laser beams. Recent studies indicate that the current heating efficiency is only 0.4%, and three requirements to achieve higher efficiency of the fast ignition (FI) scheme with the current GEKKO and LFEX systems have been identified: (i) reduction of the high energy tail of the REB; (ii) formation of a fuel core with high areal density using a limited number (twelve) of GEKKO-XII laser beams as well as a limited energy (4 kJ of 0.53-μm light in a 1.3 ns pulse); (iii) guiding and focusing of the REB to the fuel core. Laser–plasma interactions in a long-scale plasma generate electrons that are too energetic to efficiently heat the fuel core. Three actions were taken to meet the first requirement. First, the intensity contrast of the foot pulses to the main pulses of the LFEX was improved to >10{sup 9}. Second, a 5.5-mm-long cone was introduced to reduce pre-heating of the inner cone wall caused by illumination of the unconverted 1.053-μm light of implosion beam (GEKKO-XII). Third, the outside of the cone wall was coated with a 40-μm plastic layer to protect it from the pressure caused

Magnetic collimation of fast electrons in specially engineered targets irradiated by ultraintense laser pulses

International Nuclear Information System (INIS)

Cai Hongbo; Zhu Shaoping; Wu Sizhong; Chen Mo; Zhou Cangtao; He, X. T.; Yu Wei; Nagatomo, Hideo

2011-01-01

The efficient magnetic collimation of fast electron flow transporting in overdense plasmas is investigated with two-dimensional collisional particle-in-cell numerical simulations. It is found that the specially engineered targets exhibiting either high-resistivity-core-low-resistivity-cladding structure or low-density-core-high-density-cladding structure can collimate fast electrons. Two main mechanisms to generate collimating magnetic fields are found. In high-resistivity-core-low-resistivity-cladding structure targets, the magnetic field at the interfaces is generated by the gradients of the resistivity and fast electron current, while in low-density-core-high-density-cladding structure targets, the magnetic field is generated by the rapid changing of the flow velocity of the background electrons in transverse direction (perpendicular to the flow velocity) caused by the density jump. The dependences of the maximal magnetic field on the incident laser intensity and plasma density, which are studied by numerical simulations, are supported by our analytical calculations.

Free-electron laser driven by the LBNL laser-plasma accelerator

International Nuclear Information System (INIS)

Schroeder, C.B.; Fawley, W.M.; Gruner, F.; Bakeman, M.; Nakamura, K.; Robinson, K.E.; Toth, Cs.; Esarey, E.; Leemans, W.P.

2008-01-01

A design of a compact free-electron laser (FEL), generating ultra-fast, high-peak flux, XUV pulses is presented. The FEL is driven by ahigh-current, 0.5 GeV electron beam from the Lawrence Berkeley National Laboratory (LBNL) laser-plasma accelerator, whose active acceleration length is only a few centimeters. The proposed ultra-fast source (∼10 fs) would be intrinsically temporally synchronized to the drive laser pulse, enabling pump-probe studies in ultra-fast science. Owing to the high current (>10 kA) of the laser-plasma-accelerated electron beams, saturated output fluxes are potentially greater than 10 13 photons/pulse. Devices based both on self-amplified spontaneous emission and high-harmonic generated input seeds, to reduce undulator length and fluctuations, are considered.

Low Offset AC Correlator.

Science.gov (United States)

This patent describes a low offset AC correlator avoids DC offset and low frequency noise by frequency operating the correlation signal so that low...noise, low level AC amplification can be substituted for DC amplification. Subsequently, the high level AC signal is demodulated to a DC level. (Author)

5 CFR 179.307 - Administrative offset.

Science.gov (United States)

2010-01-01

... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Administrative offset. 179.307 Section 179.307 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS CLAIMS COLLECTION STANDARDS Administrative Offset § 179.307 Administrative offset. (a) If the debtor does not...

Fast electron transport in shaped solid targets

International Nuclear Information System (INIS)

Anle Lei; Cao, L.H.; He, X.T.; Zhang, W.Y.; Tanaka, K.A.; Kodama, R.; Mima, K.; Nakamura, T.; Normatsu, T.; Yu, W.

2010-01-01

Complete text of publication follows. The scheme of fast ignition fusion energy relies on the ultra-intense ultra-short (UIUS) laser energy transport into the compressed core plasma. One solution is to insert a hollow cone in the fuel shell to block the UIUS laser from the coronal plasma, thus allowing it to reach the core plasma. The cone not only can guide the UIUS laser to its tip, but can play important roles in the specific cone-in-shell target designed for FI. It was found in a PIC simulation that the cone can guide the fast electrons generated at the inner wall to propagate along the wall surface toward its tip, which would increase the energy density at the tip and might enhance the heating of the core plasma. Surface guiding of fast electrons with planar foil targets has been demonstrated experimentally. However, the guided fast electrons will mix the electrons generated ahead by the laser light with a planar target, and hence one cannot experimentally quantitatively validate the guide of the fast electrons. We investigate the cone guiding of fast electrons with an inverse cone target. We found a novel surface current of fast electrons propagating along the cone wall. The fast electrons generated at the planar outer tip of the inverse cone are guided and confined to propagate along the inverse cone wall to form a surface current by induced transient electric and magnetic fields associated with the current itself. Once departing from the source at the outer tip, this surface current of fast electrons is 'clean', neither experiencing the interacting laser light nor mixing fast electrons ahead, unlike those in cone or planar targets. This surface current in the inverse cone may explicitly give the capability of the guide of fast electron energy by the cone wall. The guiding and confinement of fast electrons is of important for fast ignition in inertial confinement fusion and several applications in high energy density science.

A study of fast electron energy transport in relativistically intense laser-plasma interactions with large density scalelengths

Energy Technology Data Exchange (ETDEWEB)

Scott, R. H. H.; Norreys, P. A. [Department of Physics, Blackett Laboratory, Imperial College London, Prince Consort Road, London, SW7 2AZ (United Kingdom); Central Laser Facility, STFC Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxford OX11 0QX (United Kingdom); Perez, F.; Baton, S. D. [LULI, Ecole Polytechnique, UMR 7605, CNRS/CEA/UPMC, Route de Saclay, 91128 Palaiseau (France); Santos, J. J.; Nicolai, Ph.; Hulin, S. [Univ. Bordeaux/CNRS/CEA, CELIA, UMR 5107, 33405 Talence (France); Ridgers, C. P. [Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom); Department of Physics, Blackett Laboratory, Imperial College London, Prince Consort Road, London, SW7 2AZ (United Kingdom); Davies, J. R. [GoLP, Instituto de Plasmas e Fusao Nuclear - Laboratorio Associado, Instituto Superior Tecnico, 1049-001 Lisboa (Portugal); Lancaster, K. L.; Trines, R. M. G. M. [Central Laser Facility, STFC Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxford OX11 0QX (United Kingdom); Bell, A. R.; Tzoufras, M. [Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom); Central Laser Facility, STFC Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxford OX11 0QX (United Kingdom); Rose, S. J. [Department of Physics, Blackett Laboratory, Imperial College London, Prince Consort Road, London, SW7 2AZ (United Kingdom)

2012-05-15

A systematic experimental and computational investigation of the effects of three well characterized density scalelengths on fast electron energy transport in ultra-intense laser-solid interactions has been performed. Experimental evidence is presented which shows that, when the density scalelength is sufficiently large, the fast electron beam entering the solid-density plasma is best described by two distinct populations: those accelerated within the coronal plasma (the fast electron pre-beam) and those accelerated near or at the critical density surface (the fast electron main-beam). The former has considerably lower divergence and higher temperature than that of the main-beam with a half-angle of {approx}20 Degree-Sign . It contains up to 30% of the total fast electron energy absorbed into the target. The number, kinetic energy, and total energy of the fast electrons in the pre-beam are increased by an increase in density scalelength. With larger density scalelengths, the fast electrons heat a smaller cross sectional area of the target, causing the thinnest targets to reach significantly higher rear surface temperatures. Modelling indicates that the enhanced fast electron pre-beam associated with the large density scalelength interaction generates a magnetic field within the target of sufficient magnitude to partially collimate the subsequent, more divergent, fast electron main-beam.

Proton Fast Ignition

International Nuclear Information System (INIS)

Key, M H; Freeman, R R; Hatchett, S P; MacKinnon, A J; Patel, P K; Snavely, R A; Stephens, R B

2006-04-01

Fast ignition (FI) by a laser generated ballistically focused proton beam is a more recently proposed alternative to the original concept of FI by a laser generated beam of relativistic electrons. It has potential advantages in less complex energy transport into dense plasma. Recent successful target heating experiments motivate further investigation of the feasibility of proton fast ignition. The concept, the physics and characteristics of the proton beams, the recent experimental work on focusing of the beams and heating of solid targets and the overall prospects for proton FI are discussed

Development of fast ignition integrated interconnecting code (FI3) for fast ignition scheme

International Nuclear Information System (INIS)

Nagatomo, H.; Johzaki, T.; Mima, K.; Sunahara, A.; Nishihara, K.; Izawa, Y.; Sakagami, H.; Nakao, Y.; Yokota, T.; Taguchi, T.

2005-01-01

The numerical simulation plays an important role in estimating the feasibility and performance of the fast ignition. There are two key issues in numerical analysis for the fast ignition. One is the controlling the implosion dynamics to form a high density core plasma in non-spherical implosion, and the other is heating core plasma efficiency by the short pulse high intense laser. From initial laser irradiation to final fusion burning, all the physics are coupling strongly in any phase, and they must be solved consistently in computational simulation. However, in general, it is impossible to simulate laser plasma interaction and radiation hydrodynamics in a single computational code, without any numerical dissipation, special assumption or conditional treatment. Recently, we have developed 'Fast Ignition Integrated Interconnecting code' (FI 3 ) which consists of collective Particle-in-Cell code, Relativistic Fokker-Planck hydro code, and 2-dimensional radiation hydrodynamics code. And those codes are connecting with each other in data-flow bases. In this paper, we will present detail feature of the FI 3 code, and numerical results of whole process of fast ignition. (author)

41 CFR 105-56.018 - Salary offset.

Science.gov (United States)

2010-07-01

... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false Salary offset. 105-56... Administration 56-SALARY OFFSET FOR INDEBTEDNESS OF FEDERAL EMPLOYEES TO THE UNITED STATES Centralized Salary Offset (CSO) Procedures-GSA as Creditor Agency § 105-56.018 Salary offset. When a match occurs and all...

41 CFR 105-56.028 - Salary offset.

Science.gov (United States)

2010-07-01

... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false Salary offset. 105-56... Administration 56-SALARY OFFSET FOR INDEBTEDNESS OF FEDERAL EMPLOYEES TO THE UNITED STATES Centralized Salary Offset (CSO) Procedures-GSA as Paying Agency § 105-56.028 Salary offset. When a match occurs and all...

34 CFR 31.11 - Offset process.

Science.gov (United States)

2010-07-01

... 34 Education 1 2010-07-01 2010-07-01 false Offset process. 31.11 Section 31.11 Education Office of the Secretary, Department of Education SALARY OFFSET FOR FEDERAL EMPLOYEES WHO ARE INDEBTED TO THE UNITED STATES UNDER PROGRAMS ADMINISTERED BY THE SECRETARY OF EDUCATION § 31.11 Offset process. (a) The...

Physical studies of fast ignition in China

International Nuclear Information System (INIS)

He, X T; Cai, Hong-bo; Wu, Si-zhong; Cao, Li-hua; Zhang, Hua; He, Ming-qing; Chen, Mo; Wu, Jun-feng; Zhou, Cang-tao; Zhou, Wei-Min; Shan, Lian-qiang; Wang, Wei-wu; Zhang, Feng; Bi, Bi; Zhao, Zong-qing; Gu, Yu-qiu; Zhang, Bao-han; Wang, Wei; Fang, Zhi-heng; Lei, An-le

2015-01-01

Fast ignition approach to inertial confinement fusion is one of the important goals today, in addition to central hot spot ignition in China. The SG-IIU and PW laser facilities are coupled to investigate the hot spot formation for fast ignition. The SG-III laser facility is almost completed and will be coupled with tens kJ PW lasers for the demonstration of fast ignition. In recent years, for physical studies of fast ignition, we have been focusing on the experimental study of implosion symmetry, M-band radiation preheating and mixing, advanced fast ignition target design, and so on. In addition, the modeling capabilities and code developments enhanced our ability to perform the hydro-simulation of the compression implosion, and the particle-in-cell (PIC) and hybrid-PIC simulation of the generation, transport and deposition of relativistic electron beams. Considerable progress has been achieved in understanding the critical issues of fast ignition. (paper)

Attention-dependent sound offset-related brain potentials.

Science.gov (United States)

Horváth, János

2016-05-01

When performing sensory tasks, knowing the potentially occurring goal-relevant and irrelevant stimulus events allows the establishment of selective attention sets, which result in enhanced sensory processing of goal-relevant events. In the auditory modality, such enhancements are reflected in the increased amplitude of the N1 ERP elicited by the onsets of task-relevant sounds. It has been recently suggested that ERPs to task-relevant sound offsets are similarly enhanced in a tone-focused state in comparison to a distracted one. The goal of the present study was to explore the influence of attention on ERPs elicited by sound offsets. ERPs elicited by tones in a duration-discrimination task were compared to ERPs elicited by the same tones in not-tone-focused attentional setting. Tone offsets elicited a consistent, attention-dependent biphasic (positive-negative--P1-N1) ERP waveform for tone durations ranging from 150 to 450 ms. The evidence, however, did not support the notion that the offset-related ERPs reflected an offset-specific attention set: The offset-related ERPs elicited in a duration-discrimination condition (in which offsets were task relevant) did not significantly differ from those elicited in a pitch-discrimination condition (in which the offsets were task irrelevant). Although an N2 reflecting the processing of offsets in task-related terms contributed to the observed waveform, this contribution was separable from the offset-related P1 and N1. The results demonstrate that when tones are attended, offset-related ERPs may substantially overlap endogenous ERP activity in the postoffset interval irrespective of tone duration, and attention differences may cause ERP differences in such postoffset intervals. © 2016 Society for Psychophysiological Research.

Offsets - An opportunity of Financing

International Nuclear Information System (INIS)

PRIN, Coralie

2008-01-01

Nuclear Research Reactors sometimes need to implement projects to upgrade, revamp or convert their reactor, acquire new fuel elements, etc. However, as their activities are mainly of noncommercial nature, they sometimes lack of financial resources to implement these projects by themselves. Several solutions exist: loans, governmental budget, subsidies from international organizations (IAEA). Offsets are another source of financing. They also are free of charge for the reactor. The objective of offsets is to Identify, implement and finance projects that: directly create or sustain a local economic activity of high-added value, would not have happened without the Obligor's intervention, and are of crucial importance given the country's political background (favor employment, technology transfers, training and education, research and development, etc.). Companies worldwide are willing to finance local projects to fulfill their Offset Obligation. Local organizations or institutions are willing to invest to increase their activities but lack of financial resources. Offset regulations are an opportunity on both sides and are free for the local organization. The monetary value of an Offset obligation is calculated as a percentage of the main contract price (or as a percentage of the imported part value). That percentage depends on the Country's legislation and on the nature of the main contract (defense or civilian). This value has to be compensated by an equivalent economic value (a Project's cost is different from its value). There is two ways of assessing a value: - Political aspects: The Project is of political importance for the country (development of an export capability, technology and/or know-how transfers) and the project in line with the country's political priorities (employment, research, international presence, etc.). - Economic benefits: the project directly sustains or creates additional activities, turnover, R and D, employment, etc. It benefits directly

Fast for sure: new developments in laser beam cutting of thin sheet metal; Mit Sicherheit schnell: neue Entwicklungen zum Laserstrahlschneiden von Fein- und Feinstblechen

Energy Technology Data Exchange (ETDEWEB)

Petring, D.; Schneider, F.; Thelen, C.; Poprawe, R.l [Fraunhofer-Institut fuer Lasertechnik (ILT), Aachen (Germany)

1999-04-01

Presently laser beam cutting is a rapidly developing technology. New laser sources with higher power and improved beam quality as well as the modern drive and control equipment together with advanced process developments allow a significant increase in cutting speed at excellent quality features. Recent results in laser beam slitting of sheet metal coils and in fast cutting of car body sheets illustrate this trend. It will be continued be even higher powers and new types of lasers. (orig.)

Magneto-optical polarization rotation in a ladder-type atomic system for tunable offset locking

Energy Technology Data Exchange (ETDEWEB)

Parniak, Michał, E-mail: michal.parniak@fuw.edu.pl; Leszczyński, Adam; Wasilewski, Wojciech [Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw (Poland)

2016-04-18

We demonstrate an easily tunable locking scheme for stabilizing frequency-sum of two lasers on a two-photon ladder transition based on polarization rotation in warm rubidium vapors induced by magnetic field and circularly polarized drive field. Unprecedented tunability of the two-photon offset frequency is due to strong splitting and shifting of magnetic states in external field. In our experimental setup, we achieve two-photon detuning of up to 700 MHz.

Concept of a staged FEL enabled by fast synchrotron radiation cooling of laser-plasma accelerated beam by solenoidal magnetic fields in plasma bubble

Science.gov (United States)

Seryi, Andrei; Lesz, Zsolt; Andreev, Alexander; Konoplev, Ivan

2017-03-01

A novel method for generating GigaGauss solenoidal fields in a laser-plasma bubble, using screw-shaped laser pulses, has been recently presented. Such magnetic fields enable fast synchrotron radiation cooling of the beam emittance of laser-plasma accelerated leptons. This recent finding opens a novel approach for design of laser-plasma FELs or colliders, where the acceleration stages are interleaved with laser-plasma emittance cooling stages. In this concept paper, we present an outline of what a staged plasma-acceleration FEL could look like, and discuss further studies needed to investigate the feasibility of the concept in detail.

Experimental study of hot electrons propagation and energy deposition in solid or laser-shock compressed targets: applications to fast igniter

International Nuclear Information System (INIS)

Pisani, F.

2000-02-01

In the fast igniter scheme, a recent approach proposed for the inertial confinement fusion, the idea is to dissociate the fuel ignition phase from its compression. The ignition phase would be then achieved by means of an external energy source: a fast electron beam generated by the interaction with an ultra-intense laser. The main goal of this work is to study the mechanisms of the hot electron energy transfer to the compressed fuel. We intent in particular to study the role of the electric and collisional effects involved in the hot electron propagation in a medium with properties similar to the compressed fuel. We carried out two experiments, one at the Vulcan laser facility (England) and the second one at the new LULI 100 TW laser (France). During the first experiment, we obtained the first results on the hot electron propagation in a dense and hot plasma. The innovating aspect of this work was in particular the use of the laser-shock technique to generate high pressures, allowing the strongly correlated and degenerated plasma to be created. The role of the electric and magnetic effects due to the space charge associated with the fast electron beam has been investigated in the second experiment. Here we studied the propagation in materials with different electrical characteristics: an insulator and a conductor. The analysis of the results showed that only by taking into account simultaneously the two propagation mechanisms (collisions and electric effects) a correct treatment of the energy deposition is possible. We also showed the importance of taking into account the induced modifications due to the electrons beam crossing the target, especially the induced heating. (author)

A transportable methane stabilized He-Ne laser

Science.gov (United States)

Akimoto, Yoshiaki

1987-06-01

The performance of a transportable methane stabilized He-Ne laser system, developed for a wavelength-optical frequency standard according to the 1983 Comite Consultatif pour la Definition du Metier, is discussed. An offset-locked laser system using a phase comparison technique is described which is used to evaluate the stabilized laser system. A frequency stability of 2.5 x 10 to the -12th tau exp -1/2, and a resettability of 1 x 10 to the -11th, are estimated for the stabilized laser system.

Magnetically Assisted Fast Ignition

OpenAIRE

Wang, W.-M.; Gibbon, P.; Sheng, Z.-M.; Li, Y.-T.

2015-01-01

Fast ignition (FI) is investigated via integrated particle-in-cell simulation including both generation andtransport of fast electrons, where petawatt ignition lasers of 2 ps and compressed targets of a peak density of300 g cm−3 and areal density of 0.49 g cm−2 at the core are taken. When a 20 MG static magnetic field isimposed across a conventional cone-free target, the energy coupling from the laser to the core is enhancedby sevenfold and reaches 14%. This value even exceeds that obtained u...

41 CFR 105-56.019 - Offset amount.

Science.gov (United States)

2010-07-01

... Administration 56-SALARY OFFSET FOR INDEBTEDNESS OF FEDERAL EMPLOYEES TO THE UNITED STATES Centralized Salary... referred for offset under this subpart is $100. (b) The amount offset from a salary payment under this... resolved to the satisfaction of GSA. ...

41 CFR 105-56.029 - Offset amount.

Science.gov (United States)

2010-07-01

... Administration 56-SALARY OFFSET FOR INDEBTEDNESS OF FEDERAL EMPLOYEES TO THE UNITED STATES Centralized Salary... salary offset under this subpart is $100. (b) The amount offset from a salary payment under this subpart... otherwise resolved to the satisfaction of the creditor agency. ...

5 CFR 1639.27 - Procedures for salary offset.

Science.gov (United States)

2010-01-01

... 5 Administrative Personnel 3 2010-01-01 2010-01-01 false Procedures for salary offset. 1639.27... Salary Offset § 1639.27 Procedures for salary offset. (a) The Board will coordinate salary deductions... pay and will implement the salary offset. (c) Deductions will begin within three official pay periods...

Design of a free-electron laser driven by the LBNL laser-plasma-accelerator

International Nuclear Information System (INIS)

Schroeder, C.B.; Fawley, W.M.; Montgomery, A.L.; Robinson, K.E.; Gruner, F.; Bakeman, M.; Leemans, W.P.

2007-01-01

We discuss the design and current status of a compact free-electron laser (FEL), generating ultra-fast, high-peak flux, VUV pulses driven by a high-current, GeV electron beam from the existing Lawrence Berkeley National Laboratory (LBNL) laser-plasma accelerator, whose active acceleration length is only a few cm. The proposed ultra-fast source would be intrinsically temporally synchronized to the drive laser pulse, enabling pump-probe studies in ultra-fast science with pulse lengths of tens of fs. Owing to the high current ( and 10 kA) of the laser-plasma-accelerated electron beams, saturated output fluxes are potentially greater than 1013 photons/pulse. Devices based both on SASE and high-harmonic generated input seeds, to reduce undulator length and fluctuations, are considered

22 CFR 309.17 - Procedures for salary offset.

Science.gov (United States)

2010-04-01

... 22 Foreign Relations 2 2010-04-01 2010-04-01 true Procedures for salary offset. 309.17 Section 309.17 Foreign Relations PEACE CORPS DEBT COLLECTION Salary Offset § 309.17 Procedures for salary offset. Unless otherwise provided by statute or contract, the following procedures apply to salary offset: (a...

7 CFR 3.46 - Offset against tax refunds.

Science.gov (United States)

2010-01-01

... 7 Agriculture 1 2010-01-01 2010-01-01 false Offset against tax refunds. 3.46 Section 3.46 Agriculture Office of the Secretary of Agriculture DEBT MANAGEMENT Administrative Offset § 3.46 Offset against tax refunds. USDA will take action to effect administrative offset against tax refunds due to debtors...

Vision and spectroscopic sensing for joint tracing in narrow gap laser butt welding

Science.gov (United States)

Nilsen, Morgan; Sikström, Fredrik; Christiansson, Anna-Karin; Ancona, Antonio

2017-11-01

The automated laser beam butt welding process is sensitive to positioning the laser beam with respect to the joint because a small offset may result in detrimental lack of sidewall fusion. This problem is even more pronounced in case of narrow gap butt welding, where most of the commercial automatic joint tracing systems fail to detect the exact position and size of the gap. In this work, a dual vision and spectroscopic sensing approach is proposed to trace narrow gap butt joints during laser welding. The system consists of a camera with suitable illumination and matched optical filters and a fast miniature spectrometer. An image processing algorithm of the camera recordings has been developed in order to estimate the laser spot position relative to the joint position. The spectral emissions from the laser induced plasma plume have been acquired by the spectrometer, and based on the measurements of the intensities of selected lines of the spectrum, the electron temperature signal has been calculated and correlated to variations of process conditions. The individual performances of these two systems have been experimentally investigated and evaluated offline by data from several welding experiments, where artificial abrupt as well as gradual deviations of the laser beam out of the joint were produced. Results indicate that a combination of the information provided by the vision and spectroscopic systems is beneficial for development of a hybrid sensing system for joint tracing.

5 CFR 179.211 - Notice of salary offset.

Science.gov (United States)

2010-01-01

... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Notice of salary offset. 179.211 Section... COLLECTION STANDARDS Salary Offset § 179.211 Notice of salary offset. (a) Upon receipt of proper... certification as the debtor, a written notice of salary offset. Such notice shall, at a minimum: (1) State that...

Generation and transport of fast electrons in the interaction of high intensity laser with matter; Generation et transport des electrons rapides dans l'interaction laser-matiere a haut flux

Energy Technology Data Exchange (ETDEWEB)

Popescu, H

2005-10-15

The general context of this study is the Inertial Confinement for thermonuclear controlled fusion and, more precisely, the Fast Igniter (FI). In this context the knowledge of the generation and transport of fast electrons is crucial. This thesis is an experimental study of the generation and transport of fast electrons in the interaction of a high intensity laser ({>=} 10{sup 19} W/cm{sup 2}) with a solid target. The main diagnostic used here is the transition radiation. This radiation depends on the electrons which produce it and thus it gives important information on the electrons: energy, temperature, propagation geometry, etc. The spectral, temporal and spatial analysis permitted to put in evidence the acceleration of periodic electron bunches which, in this case, emit a Coherent Transition Radiation (CTR). During this thesis we have developed some theoretical models in order to explain the experimental results. We find this way two kinds of electron bunches, emitted either at the laser frequency ({omega}{sub 0}), either at the double of this frequency (2{omega}{sub 0}), involving several acceleration mechanisms: vacuum heating / resonance absorption and Lorentz force, respectively. These bunches are also observed in the PIC (particle-in-cell) simulations. The electron temperature is of about 2 MeV in our experimental conditions. The electrons are emitted starting from a point source (which is the laser focal spot) and then propagate in a ballistic way through the target. In some cases they can be re-injected in the target by the electrostatic field from the target edges. This diagnostic is only sensitive to the coherent relativistic electrons, which explains the weak total energy that they contain (about a few mJ). The CTR signal emitted by those fast electrons is largely dominating the signal emitted by the less energetic electrons, even if they contain the major part of the energy (about 1 J). (author)

Enhanced Model for Fast Ignition

Energy Technology Data Exchange (ETDEWEB)

Mason, Rodney J. [Research Applications Corporation, Los Alamos, NM (United States)

2010-10-12

Laser Fusion is a prime candidate for alternate energy production, capable of serving a major portion of the nation's energy needs, once fusion fuel can be readily ignited. Fast Ignition may well speed achievement of this goal, by reducing net demands on laser pulse energy and timing precision. However, Fast Ignition has presented a major challenge to modeling. This project has enhanced the computer code ePLAS for the simulation of the many specialized phenomena, which arise with Fast Ignition. The improved code has helped researchers to understand better the consequences of laser absorption, energy transport, and laser target hydrodynamics. ePLAS uses efficient implicit methods to acquire solutions for the electromagnetic fields that govern the accelerations of electrons and ions in targets. In many cases, the code implements fluid modeling for these components. These combined features, "implicitness and fluid modeling," can greatly facilitate calculations, permitting the rapid scoping and evaluation of experiments. ePLAS can be used on PCs, Macs and Linux machines, providing researchers and students with rapid results. This project has improved the treatment of electromagnetics, hydrodynamics, and atomic physics in the code. It has simplified output graphics, and provided new input that avoids the need for source code access by users. The improved code can now aid university, business and national laboratory users in pursuit of an early path to success with Fast Ignition.

Boundary Layer Instabilities Generated by Freestream Laser Perturbations

Science.gov (United States)

Chou, Amanda; Schneider, Steven P.

2015-01-01

A controlled, laser-generated, freestream perturbation was created in the freestream of the Boeing/AFOSR Mach-6 Quiet Tunnel (BAM6QT). The freestream perturbation convected downstream in the Mach-6 wind tunnel to interact with a flared cone model. The geometry of the flared cone is a body of revolution bounded by a circular arc with a 3-meter radius. Fourteen PCB 132A31 pressure transducers were used to measure a wave packet generated in the cone boundary layer by the freestream perturbation. This wave packet grew large and became nonlinear before experiencing natural transition in quiet flow. Breakdown of this wave packet occurred when the amplitude of the pressure fluctuations was approximately 10% of the surface pressure for a nominally sharp nosetip. The initial amplitude of the second mode instability on the blunt flared cone is estimated to be on the order of 10 -6 times the freestream static pressure. The freestream laser-generated perturbation was positioned upstream of the model in three different configurations: on the centerline, offset from the centerline by 1.5 mm, and offset from the centerline by 3.0 mm. When the perturbation was offset from the centerline of a blunt flared cone, a larger wave packet was generated on the side toward which the perturbation was offset. The offset perturbation did not show as much of an effect on the wave packet on a sharp flared cone as it did on a blunt flared cone.

12 CFR 1408.39 - Procedures for salary offset.

Science.gov (United States)

2010-01-01

... 12 Banks and Banking 7 2010-01-01 2010-01-01 false Procedures for salary offset. 1408.39 Section... STATES Offset Against Salary § 1408.39 Procedures for salary offset. (a) The Chairman, or designee of the... periods following the date of mailing or delivery of the Notice of Intent to Collect by Salary Offset. (c...

12 CFR 608.839 - Procedures for salary offset.

Science.gov (United States)

2010-01-01

... 12 Banks and Banking 6 2010-01-01 2010-01-01 false Procedures for salary offset. 608.839 Section... OWED THE UNITED STATES Offset Against Salary § 608.839 Procedures for salary offset. (a) The Chairman... Intent to Collect by Salary Offset. (c)(1) If the amount of the debt is equal to or is less than 15...

Effect of prepulse on fast electron lateral transport at the target surface irradiated by intense femtosecond laser pulses

International Nuclear Information System (INIS)

Lin, X. X.; Li, Y. T.; Liu, B. C.; Liu, F.; Du, F.; Wang, S. J.; Lu, X.; Chen, L. M.; Zhang, L.; Liu, X.; Wang, J.; Liu, F.; Liu, X. L.; Wang, Z. H.; Ma, J. L.; Wei, Z. Y.; Zhang, J.

2010-01-01

The effects of preplasma on lateral fast electron transport at front target surface, irradiated by ultraintense (>10 18 W/cm 2 ) laser pulses, are investigated by Kα imaging technique. A large annular Kα halo with a diameter of ∼560 μm surrounding a central spot is observed. A specially designed steplike target is used to identify the possible mechanisms. It is believed that the halos are mainly generated by the lateral diffusion of fast electrons due to the electrostatic and magnetic fields in the preplasma. This is illustrated by simulated electron trajectories using a numerical model.

13 CFR 120.1722 - SBA's offset rights.

Science.gov (United States)

2010-01-01

... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false SBA's offset rights. 120.1722... of SBA Secondary Market Guarantee Program for First Lien Position 504 Loan Pools § 120.1722 SBA's offset rights. SBA shall have the right to offset any amount owed by Lender to SBA, including, without...

Utilization of curve offsets in additive manufacturing

Science.gov (United States)

Haseltalab, Vahid; Yaman, Ulas; Dolen, Melik

2018-05-01

Curve offsets are utilized in different fields of engineering and science. Additive manufacturing, which lately becomes an explicit requirement in manufacturing industry, utilizes curve offsets widely. One of the necessities of offsetting is for scaling which is required if there is shrinkage after the fabrication or if the surface quality of the resulting part is unacceptable. Therefore, some post-processing is indispensable. But the major application of curve offsets in additive manufacturing processes is for generating head trajectories. In a point-wise AM process, a correct tool-path in each layer can reduce lots of costs and increase the surface quality of the fabricated parts. In this study, different curve offset generation algorithms are analyzed to show their capabilities and disadvantages through some test cases and improvements on their drawbacks are suggested.

The carrier transport mechanism and band offset at the interface of ZnO/n-Si(111) heterojunction

Energy Technology Data Exchange (ETDEWEB)

Li, Yapeng, E-mail: liyp1984@126.com [School of Materials Science and Engineering, Shaanxi University of Technology, Hanzhong 723001 (China); Li, Yingfeng [School of Electrical Engineering, Shaanxi University of Technology, Hanzhong 723001 (China); Wang, Jianyuan [School of Nature and Applied Science, Northwestern Polytechnical University, Xi' an 710072 (China); He, Zhirong; Zhang, Yonghong; Yu, Qi; Hou, Juncai [School of Materials Science and Engineering, Shaanxi University of Technology, Hanzhong 723001 (China)

2017-05-15

Highlights: • The carrier transport deviated from ideal thermionic emission model. • One deep level present at the interface of ZnO/n-Si(111) heterojunction. • The band offsets of ZnO/n-Si(111) heterojunction are a type-II band alignment. - Abstract: The ZnO films were deposited on the surface of n-Si(111) substrate by pulsed laser deposition for fabrication of ZnO/n-Si(111) heterojunction. The carrier transport mechanism, deep level defects and band offsets at the interface of ZnO/n-Si(111) heterojunction were investigated by current- voltage measurement, deep level transient spectroscopy, X-ray photoelectron spectroscopy, respectively. The results showed that the barrier height and ideality factor values varied in the different linear voltage range by using the thermionic emission model, which was due to the deep level participated in carrier transport. Meanwhile, it was found that one deep level appeared at the interface of ZnO/n-Si(111) heterojunction with densities of the deep level about 8.5 × 10{sup 16} cm{sup −3} and activation energies about 224 m eV, which originated from O{sup 2−} vacancies of ZnO films. In addition, the valence band offset of the ZnO/n-Si(111) heterojunction can be calculated to be −2.4 ± 0.15 eV. The conduction band offset is deduced to be −3.5 ± 0.15 eV from the valence band offset value, indicating that the band offsets of ZnO/n-Si(111) heterojunction is a type-II band alignment.

10 CFR 1015.215 - Federal salary offset.

Science.gov (United States)

2010-01-01

... 10 Energy 4 2010-01-01 2010-01-01 false Federal salary offset. 1015.215 Section 1015.215 Energy... Administrative Collection of Claims § 1015.215 Federal salary offset. (a) DOE may authorize Treasury to offset a Federal salary to satisfy delinquent debt in accordance with 5 U.S.C. 5514, Installment Deduction for...

Coherent spectroscopy of a {Lambda} atomic system and its prospective application to tunable frequency offset locking

Energy Technology Data Exchange (ETDEWEB)

Kale, Y B [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Ray, Ayan [Radioactive Ion Beam Group, Variable Energy Cyclotron Centre, Kolkata 700064 (India); Lawande, Q V [Theoretical Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Jagatap, B N, E-mail: yogeshwar84@rediffmail.com, E-mail: ayan_ray_in@rediffmail.com, E-mail: bnj@barc.gov.in [Atomic and Molecular Physics Division and Homi Bhabha National Institute, Bhabha Atomic Research Centre, Mumbai 400 085 (India)

2011-09-15

We investigate the coherent pump-probe spectroscopy of a three-level {Lambda} system, 6s{sub 1/2}F = 3,4{yields}6p{sub 3/2}F{sup '}= 4, in the hyperfine manifold of D{sub 2} transition (852 nm) of cesium with particular reference to the sub-Doppler linewidth resonance arising from Aulter-Townes (AT) splitting and the possibility of using it for realizing a scheme for tunable atomic frequency offset locking (AFOL). We discuss here the theoretical framework for a {Lambda} system interacting with a coherent pump and probe and use it to describe the process of modulation transfer in the AT and electromagnetically induced transparency regimes. We further employ an experimental scheme consisting of a strong pump and a pair of weak probes to resolve the sub-Doppler linewidth ({approx}8 MHz) AT resonance and study its dependence on pump intensity and detuning. In order to explore the possibility of using such a sub-Doppler linewidth resonance for AFOL, we use its first derivative signal as a frequency discriminator to stabilize the probe laser. The frequency stability of the probe is characterized by means of error signal analysis. This study reveals that while the frequency stability of the AT locked laser is limited by the pump laser, the tuning range of the offset frequency lock can cover the entire Doppler profile and its immediate neighbourhood, thereby providing a simple and cost effective alternative to the external modulator. The study described in this paper contributes to the discussion on the subtle link between dressed state spectroscopy and AFOL, which is relevant for developing a master-slave-type laser system in the domain of coherent photon-atom interaction.

Fast diamond photoconductors

International Nuclear Information System (INIS)

Pochet, T.

1993-01-01

Preliminary results on the response of type Ib and IIa diamond photodetectors to fast laser pulse exposures at 265 and 530 nm are presented. The influence of the applied bias, the laser wavelengths and the light intensity on the detector sensitivity is studied. Also, recent measurements with 1.25 MeV gamma ray pulses are reported. (authors). 13 refs., 7 figs., 1 tab

Development of key technologies in DPSSL system for fast-ignition, laser fusion reactor - FIREX, HALNA, and protection of final optics

International Nuclear Information System (INIS)

Norimatsu, T.; Azechi, H.; Fujimoto, Y.; Jitsuno, T.; Kanabe, T.; Kodama, R.; Kondo, K.; Miyanaga, N.; Nagatomo, H.; Nakatsuka, M.; Shiraga, H.; Tanaka, K.A.; Tsubakimoto, K.; Yamanaka, M.; Yasuhara, R.; Izawa, Y.; Kawashima, T.; Kurita, T.; Matsumoto, O.; Tsuchiya, Y.; Sekine, T.; Kan, H.

2005-01-01

A critical path to a laser fusion power plant is construction of a reliable, efficient, high repetitive energy driver including the relation with the reactor environment. At ILE, Osaka University, FIREX project has been proposed and the phase I to show heating of compressed fuel to 5 keV has started with construction of the FIREX laser. This project will demonstrate physics of fast ignition and elemental studies are carried out to obtain persuasive data to find the path to the goal. A diode-laser-pumped, solid-state-laser (DPSSL) HALNA-10 succeeded in operation of 7.5J output power at 10 Hz rep-rate. Contamination of final optics by metal vapor was studied using a 1/10 model of the beam duct. The result indicated that contamination can be controlled with high speed shutters and a low pressure buffer gas. (author)

Effects of buried high-Z layers on fast electron propagation

International Nuclear Information System (INIS)

Yang, Xiaohu; Zhuo, Hongbin; Ma, Yanyun; Shao, Fuqiu; Xu, Han; Yin Yan; Borghesi, M.

2014-01-01

The transport through high density plasmas of relativistic electron beams generated by ultra-intense laser-plasma interaction has potential applications in laser-driven ion acceleration and in the fast igniter scheme for inertial confinement fusion. By extending a prior model [A.R. Bell, J.R. Davies, S.M. Guerin, Phys. Rev. E 58, 2471 (1998)], the magnetic field generated during the transport of a fast electron beam driven by an ultra-intense laser in a solid target is derived analytically and applied to estimate the effect of such field on fast electron propagation through a buried high-Z layer in a lower-Z target. It is found that the effect gets weaker with the increase of the depth of the buried layer, the divergence of the fast electrons, and the laser intensity, indicating that magnetic field effects on the fast electron divergence as measured from K a X-ray emission may need to be considered for moderate laser intensities. On the basis of the calculations, some considerations are made on how one can mitigate the effect of the magnetic field generated at the interface. (authors)

A direct-conversion WLAN transceiver baseband with DC offset compensation and carrier leakage reduction

Energy Technology Data Exchange (ETDEWEB)

Yuan Fang; Yan Jun; Ma Heping; Shi Yin [Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China); Foster, Dai Fa, E-mail: fyuan@sci-inc.com.c [Department of Electrical and Computer Engineering, Auburn University, Auburn, AL 36849-5201 (United States)

2010-10-15

A dual-band direct-conversion WLAN transceiver baseband compliant with the IEEE 802.11a/b/g standards is described. Several critical techniques for receiver DC offset compensation and transmitter carrier leakage rejection calibration are presented that enable the direct-conversion architecture to meet all WLAN specifications. The receiver baseband VGA provides 62 dB gain range with steps of 2 dB and a DC offset cancellation circuit is introduced to remove the offset from layout and self-mixing. The calibration loop achieves constant high-pass pole when gain changes; and a fast response time by programming the pole to 1 MHz during preamble and to 30 kHz during receiving data. The transmitter baseband employs an auto-calibration loop with on-chip AD and DA to suppress the carrier leakage, and AD can be powered down after calibration to save power consumption. The chip consumes 17.52 mA for RX baseband VGA and DCOC, and 8.3 mA for TX carrier leakage calibration (5.88 mA after calibration) from 2.85 V supply. Implemented in a 0.35 {mu}m SiGe technology, they occupy 0.68 mm{sup 2} and 0.18 mm{sup 2} die size respectively. (semiconductor integrated circuits)

Transcanalicular laser dacryocystorhinostomy using low energy 810 nm diode laser

Directory of Open Access Journals (Sweden)

Sanjiv K Gupta

2012-01-01

Conclusions: Transcanalicular Laser DCR can be safely performed using a low power 810 nm diode laser. The surgery is elegant, minimally invasive, allows fast rehabilitation, and has an excellent success rate.

Emissions trading with offset markets and free quota allocations

Energy Technology Data Exchange (ETDEWEB)

Rosendahl, Knut Einar; Strand, Jon

2012-07-01

We study interactions between a 'policy bloc's' emissions quota market and an offset market where emissions offsets can be purchased from a non-policy 'fringe' of countries (such as for the CDM under the Kyoto Protocol). Policy-bloc firms are assumed to benefit from free quota allocations that are updated according to either past emissions or past outputs. We show that both overall abatement, and the allocation of given abatement between the policy bloc and the fringe, tend to be inefficient. When the policy-bloc quota market and offset markets are fully integrated (and firms buy offsets directly from the fringe), and all quotas and offsets must be traded at a single price, it is optimal for the policy bloc to either not constrain the offset market whatsoever, or to ban offsets completely. The former (latter) case occurs when free allocation of quotas is not too generous (very generous), and the offset market can profitably deliver large (only a small) quota amounts. Governments of policy countries would however instead prefer to buy offsets directly from the fringe at a price below the policy-bloc quota price. The offset price will then be below the marginal damage cost of emissions, and the quota price in the policy bloc above marginal damage cost. This solution is also inefficient as the policy bloc (acting as a monopsonist) purchases too few offsets from the fringe.(Author)

Intensity-Stabilized Fast-Scanned Direct Absorption Spectroscopy Instrumentation Based on a Distributed Feedback Laser with Detection Sensitivity down to 4 × 10−6

Directory of Open Access Journals (Sweden)

Gang Zhao

2016-09-01

Full Text Available A novel, intensity-stabilized, fast-scanned, direct absorption spectroscopy (IS-FS-DAS instrumentation, based on a distributed feedback (DFB diode laser, is developed. A fiber-coupled polarization rotator and a fiber-coupled polarizer are used to stabilize the intensity of the laser, which significantly reduces its relative intensity noise (RIN. The influence of white noise is reduced by fast scanning over the spectral feature (at 1 kHz, followed by averaging. By combining these two noise-reducing techniques, it is demonstrated that direct absorption spectroscopy (DAS can be swiftly performed down to a limit of detection (LOD (1σ of 4 × 10−6, which opens up a number of new applications.

A scheme for recording a fast process at nanosecond scale by using digital holographic interferometry with continuous wave laser

Science.gov (United States)

Wang, Jun; Zhao, Jianlin; Di, Jianglei; Jiang, Biqiang

2015-04-01

A scheme for recording fast process at nanosecond scale by using digital holographic interferometry with continuous wave (CW) laser is described and demonstrated experimentally, which employs delayed-time fibers and angular multiplexing technique and can realize the variable temporal resolution at nanosecond scale and different measured depths of object field at certain temporal resolution. The actual delay-time is controlled by two delayed-time fibers with different lengths. The object field information in two different states can be simultaneously recorded in a composite hologram. This scheme is also suitable for recording fast process at picosecond scale, by using an electro-optic modulator.

D-Cluster Converter Foil for Laser-Accelerated Deuteron Beams: Towards Deuteron-Beam-Driven Fast Ignition

International Nuclear Information System (INIS)

Miley, George H.

2012-01-01

Fast Ignition (FI) uses Petawatt laser generated particle beam pulse to ignite a small volume called a pre-compressed Inertial Confinement Fusion (ICF) target, and is the favored method to achieve the high energy gain per target burn needed for an attractive ICF power plant. Ion beams such as protons, deuterons or heavier carbon ions are especially appealing for FI as they have relative straight trajectory, and easier to focus on the fuel capsule. But current experiments have encountered problems with the 'converter-foil' which is irradiated by the Petawatt laser to produce the ion beams. The problems include depletion of the available ions in the convertor foils, and poor energy efficiency (ion beam energy/ input laser energy). We proposed to develop a volumetrically-loaded ultra-high-density deuteron deuterium cluster material as the basis for converter-foil for deuteron beam generation. The deuterons will fuse with the ICF DT while they slow down, providing an extra 'bonus' energy gain in addition to heating the hot spot. Also, due to the volumetric loading, the foil will provide sufficient energetic deuteron beam flux for 'hot spot' ignition, while avoiding the depletion problem encountered by current proton-driven FI foils. After extensive comparative studies, in Phase I, high purity PdO/Pd/PdO foils were selected for the high packing fraction D-Cluster converter foils. An optimized loading process has been developed to increase the cluster packing fraction in this type of foil. As a result, the packing fraction has been increased from 0.1% to 10% - meeting the original Phase I goal and representing a significant progress towards the beam intensities needed for both FI and pulsed neutron applications. Fast Ignition provides a promising approach to achieve high energy gain target performance needed for commercial Inertial Confinement Fusion (ICF). This is now a realistic goal for near term in view of the anticipated ICF target burn at the National Ignition

22 CFR 1007.8 - Procedures for salary offset.

Science.gov (United States)

2010-04-01

... 22 Foreign Relations 2 2010-04-01 2010-04-01 true Procedures for salary offset. 1007.8 Section 1007.8 Foreign Relations INTER-AMERICAN FOUNDATION SALARY OFFSET § 1007.8 Procedures for salary offset... final salary or leave payments in accordance with 31 U.S.C. 3716. ...

17 CFR 141.8 - Procedures for salary offset.

Science.gov (United States)

2010-04-01

... 17 Commodity and Securities Exchanges 1 2010-04-01 2010-04-01 false Procedures for salary offset. 141.8 Section 141.8 Commodity and Securities Exchanges COMMODITY FUTURES TRADING COMMISSION SALARY OFFSET § 141.8 Procedures for salary offset. (a) Deductions to liquidate an employee's debt will be by...

38 CFR 1.992 - Procedures for salary offset.

Science.gov (United States)

2010-07-01

... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false Procedures for salary offset. 1.992 Section 1.992 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS GENERAL PROVISIONS Salary Offset Provisions § 1.992 Procedures for salary offset. (a) Types of collection...

22 CFR 34.16 - Procedures for salary offset.

Science.gov (United States)

2010-04-01

... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Procedures for salary offset. 34.16 Section 34.16 Foreign Relations DEPARTMENT OF STATE CLAIMS AND STOLEN PROPERTY DEBT COLLECTION Salary Offset § 34.16 Procedures for salary offset. Unless otherwise provided by statute or contract, the following...

New solid laser: Ceramic laser. From ultra stable laser to ultra high output laser

International Nuclear Information System (INIS)

Ueda, Kenichi

2006-01-01

An epoch-making solid laser is developed. It is ceramic laser, polycrystal, which is produced as same as glass and shows ultra high output. Ti 3+ :Al 2 O 3 laser crystal and the CPA (chirped pulse amplification) technique realized new ultra high output lasers. Japan has developed various kinds of ceramic lasers, from 10 -2 to 67 x 10 3 w average output, since 1995. These ceramic lasers were studied by gravitational radiation astronomy. The scattering coefficient of ceramic laser is smaller than single crystals. The new fast ignition method is proposed by Institute of Laser Engineering of Osaka University, Japan. Ultra-intense short pulse laser can inject the required energy to the high-density imploded core plasma within the core disassembling time. Ti 3+ :Al 2 O 3 crystal for laser, ceramic YAG of large caliber for 100 kW, transparent laser ceramic from nano-crystals, crystal grain and boundary layer between grains, the scattering coefficient of single crystal and ceramic, and the derived release cross section of Yb:YAG ceramic are described. (S.Y.)

A fast automatic power control circuit for a small form-factor pluggable laser diode drive

Energy Technology Data Exchange (ETDEWEB)

Wang Huan; Wang Zhigong; Xu Jian; Miao Peng; Li Wei [Institute of RF- and OE-ICs, Southeast University, Nanjing 210096 (China); Luo Yin; Yang Siyong, E-mail: wanghuan@seu.edu.c [Jiangsu Sino-Chip OE-IC Co. Ltd, Nanjing 210016 (China)

2010-06-15

A fast automatic power control (APC) circuit for a laser diode driver (LDD) has been implemented in a 0.6-{mu}m BiCMOS process. The APC circuit adopts double-loops and variable-bandwidth techniques to achieve a turn-on time of < 400 {mu}s for most kinds of TOSAs. Thus, it meets the small form-factor pluggable (SFP) agreement. Such techniques make a good tradeoff between stability, accuracy, turn-on time, noise and convenience. The measured results indicate that the APC circuit is suitable for SFP LDD. (semiconductor integrated circuits)

16 CFR 1027.8 - Procedures for salary offset.

Science.gov (United States)

2010-01-01

... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Procedures for salary offset. 1027.8 Section 1027.8 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION GENERAL SALARY OFFSET § 1027.8 Procedures for salary offset. (a) Deductions to liquidate an employee's debt will be by the method and in the...

5 CFR 1215.8 - Procedures for salary offset.

Science.gov (United States)

2010-01-01

... 5 Administrative Personnel 3 2010-01-01 2010-01-01 false Procedures for salary offset. 1215.8... MANAGEMENT Salary Offset § 1215.8 Procedures for salary offset. (a) Deductions to liquidate an employee's... payment due to a separated employee including but not limited to final salary payment or leave in...

45 CFR 607.8 - Procedures for salary offset.

Science.gov (United States)

2010-10-01

... 45 Public Welfare 3 2010-10-01 2010-10-01 false Procedures for salary offset. 607.8 Section 607.8 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION SALARY OFFSET § 607.8 Procedures for salary offset. (a) Deductions to liquidate an employee's debt will be by...

32 CFR 1697.8 - Procedures for salary offset.

Science.gov (United States)

2010-07-01

... 32 National Defense 6 2010-07-01 2010-07-01 false Procedures for salary offset. 1697.8 Section 1697.8 National Defense Other Regulations Relating to National Defense SELECTIVE SERVICE SYSTEM SALARY OFFSET § 1697.8 Procedures for salary offset. (a) Deductions to liquidate an employee's debt will be by...

14 CFR 1261.603 - Procedures for salary offset.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Procedures for salary offset. 1261.603... salary offset. If NASA is both the paying and creditor agency, the following requirements must be met... of the debt through salary offset by deductions from the employee's current disposable pay, stating...

5 CFR 179.212 - Procedures for salary offset.

Science.gov (United States)

2010-01-01

... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Procedures for salary offset. 179.212... COLLECTION STANDARDS Salary Offset § 179.212 Procedures for salary offset. (a) The Director or his or her designee shall coordinate salary deductions under this subpart. (b) OPM payroll office shall determine the...

47 CFR 1.1951 - Offset against tax refunds.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 1 2010-10-01 2010-10-01 false Offset against tax refunds. 1.1951 Section 1... Claims Owed the United States Cooperation with the Internal Revenue Service § 1.1951 Offset against tax refunds. The Commission will take action to effect administrative offset against tax refunds due to...

Governing the carbon offset market

OpenAIRE

Lovell, Heather C.

2010-01-01

Carbon offsets are produced and sold under the international climate change regime (the United Nations Kyoto Protocol) and also within an expanding voluntary offset market in which companies and individuals can voluntarily opt to compensate for their greenhouse gas emissions. The volume of carbon produced and consumed within compliance and voluntary markets has grown dramatically in the last 5 years, raising a number of governance challenges. This Focus Article gives an overview of the govern...

Fast photography of XeCl laser-induced plasma of graphite in vacuum and in nitrogen atmosphere

International Nuclear Information System (INIS)

Acquaviva, S; De Giorgi, M L

2003-01-01

Fast photography with a gated intensified close-coupled device camera was applied to provide a visualization of the temporal and spatial evolution of chemical species in a plasma induced by a 308 nm laser during graphite ablation, in vacuum and in nitrogen atmosphere. A sequence of frames of the luminous plume was recorded, using narrow interference filters, and plasma expansion velocity was estimated from the acquired images. Present observations agree with optical emission spectroscopic investigations performed under the same experimental conditions

29 CFR 1650.110 - Implementation of salary offset.

Science.gov (United States)

2010-07-01

... 29 Labor 4 2010-07-01 2010-07-01 false Implementation of salary offset. 1650.110 Section 1650.110... Procedures for the Collection of Debts by Salary Offset § 1650.110 Implementation of salary offset. (a... proposed voluntary repayment agreement, deductions will begin in the next bi-weekly salary payment after a...

45 CFR 33.10 - Procedures for salary offset.

Science.gov (United States)

2010-10-01

... 45 Public Welfare 1 2010-10-01 2010-10-01 false Procedures for salary offset. 33.10 Section 33.10 Public Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL ADMINISTRATION SALARY OFFSET § 33.10 Procedures for salary offset. (a) Method and source of deductions. Unless the employee and the Secretary have...

Angle-sensitive and fast photovoltage of silver nanocluster embeded ZnO thin films induced by 1.064-μm pulsed laser

International Nuclear Information System (INIS)

Song-Qing, Zhao; Li-Min, Yang; Wen-Wei, Liu; Kun, Zhao; Yue-Liang, Zhou; Qing-Li, Zhou

2010-01-01

Silver nanocluster embedded ZnO composite thin film was observed to have an angle-sensitive and fast photovoltaic effect in the angle range from −90° to 90°, its peak value and the polarity varied regularly with the angle of incidence of the 1.064-μm pulsed Nd:YAG laser radiation onto the ZnO surface. Meanwhile, for each photovoltaic signal, its rising time reached ∼2 ns with an open-circuit photovoltage of ∼2 ns full width at half-maximum. This angle-sensitive fast photovoltaic effect is expected to put this composite film a candidate for angle-sensitive and fast photodetector. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

40 CFR 13.21 - Employee salary offset-general.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Employee salary offset-general. 13.21... STANDARDS Administrative Offset § 13.21 Employee salary offset—general. (a) Purpose. This section... collection by salary offset under 5 U.S.C. 5514 of debts owed EPA and debts owed to other Federal agencies by...

45 CFR 708.10 - Procedures for salary offset.

Science.gov (United States)

2010-10-01

... 45 Public Welfare 3 2010-10-01 2010-10-01 false Procedures for salary offset. 708.10 Section 708... COLLECTION BY SALARY OFFSET FROM INDEBTED CURRENT AND FORMER EMPLOYEES § 708.10 Procedures for salary offset... to final salary payment, retired pay, or lump sum leave, etc. as of the date of separation to the...

Modematic: a fast laser beam analyzing system for high power CO2-laser beams

Science.gov (United States)

Olsen, Flemming O.; Ulrich, Dan

2003-03-01

The performance of an industrial laser is very much depending upon the characteristics of the laser beam. The ISO standards 11146 and 11154 describing test methods for laser beam parameters have been approved. To implement these methods in industry is difficult and especially for the infrared laser sources, such as the CO2-laser, the availabl analyzing systems are slow, difficult to apply and having limited reliability due to the nature of the detection methods. In an EUREKA-project the goal was defined to develop a laser beam analyzing system dedicated to high power CO2-lasers, which could fulfill the demands for an entire analyzing system, automating the time consuming pre-alignment and beam conditioning work required before a beam mode analyses, automating the analyzing sequences and data analysis required to determine the laser beam caustics and last but not least to deliver reliable close to real time data to the operator. The results of this project work will be described in this paper. The research project has led to the development of the Modematic laser beam analyzer, which is ready for the market.

Economic and ecological outcomes of flexible biodiversity offset systems.

Science.gov (United States)

Habib, Thomas J; Farr, Daniel R; Schneider, Richard R; Boutin, Stan

2013-12-01

The commonly expressed goal of biodiversity offsets is to achieve no net loss of specific biological features affected by development. However, strict equivalency requirements may complicate trading of offset credits, increase costs due to restricted offset placement options, and force offset activities to focus on features that may not represent regional conservation priorities. Using the oil sands industry of Alberta, Canada, as a case study, we evaluated the economic and ecological performance of alternative offset systems targeting either ecologically equivalent areas (vegetation types) or regional conservation priorities (caribou and the Dry Mixedwood natural subregion). Exchanging dissimilar biodiversity elements requires assessment via a generalized metric; we used an empirically derived index of biodiversity intactness to link offsets with losses incurred by development. We considered 2 offset activities: land protection, with costs estimated as the net present value of profits of petroleum and timber resources to be paid as compensation to resource tenure holders, and restoration of anthropogenic footprint, with costs estimated from existing restoration projects. We used the spatial optimization tool MARXAN to develop hypothetical offset networks that met either the equivalent-vegetation or conservation-priority targets. Networks that required offsetting equivalent vegetation cost 2-17 times more than priority-focused networks. This finding calls into question the prudence of equivalency-based systems, particularly in relatively undeveloped jurisdictions, where conservation focuses on limiting and directing future losses. Priority-focused offsets may offer benefits to industry and environmental stakeholders by allowing for lower-cost conservation of valued ecological features and may invite discussion on what land-use trade-offs are acceptable when trading biodiversity via offsets. Resultados Económicos y Ecológicos de Sistemas de Compensación de

Diamond Light Source Booster fast orbit feedback system

International Nuclear Information System (INIS)

Gayadeen, S.; Duncan, S.R.; Christou, C.; Heron, M.T.; Rowland, J.

2012-01-01

The Fast Orbit Feedback system that has been installed on the Diamond Light Source Storage ring has been replicated on the Booster synchrotron in order to provide a test bed for the development of the Storage Ring controller design. To realise this the Booster is operated in DC mode. The electron beam is regulated in two planes using the Fast Orbit Feedback system, which takes the beam position from 22 beam position monitors for each plane, and calculates offsets to 44 corrector power supplies at a sample rate of 10 kHz. This paper describes the design and realization of the controller for the Booster Fast Orbit Feedback, presents results from the implementation and considers future development

Experimental study of fast electron transport in the framework of fast ignition for inertial fusion

International Nuclear Information System (INIS)

Vauzour, B.

2012-01-01

The framework of this PhD thesis is the validation of the fast ignition scheme for the nuclear fusion by inertial confinement. It consists in the experimental study of the various processes involved in fast electron beams propagation, produced by intense laser pulses (10 19 W.cm -2 ), through dense matter either solid or compressed. In this work we present the results of three experiments carried out on different laser facilities in order to generate fast electron beams in various conditions and study their propagation in different states of matter, from the cold solid to the warm and dense plasma.The first experiment was performed with a high intensity contrast on the UHI100 laser facility (CEA Saclay). The study of fast electron energy deposition inside thin aluminium targets highlights a strong target heating at shallow depths, where the collective effects are predominant, thus producing a steep temperature profile between front (300 eV) and rear (20 eV) sides over 20μm thickness. A numerical simulation of the experiment shows that this temperature gradient induces the formation of a shock wave, breaking through the rear side of the target and thus leading to increase the thermal emission. The experimental chronometry of the shock breakthrough allowed validating the model of the collective transport of electrons.Two other experiments were dedicated to the study of fast electron beam propagation inside compressed targets. In the first experiment on the LULI2000 laser facility, the plane compression geometry allowed to precisely dissociate the energy losses due to resistive effects from those due to the collisional ones. By comparing our experimental results with simulations, we observed a significative increase of the fast electron beam energy losses with the compression and the target heating to temperatures close to the Fermi temperature. The second experiment, performed in a cylindrical geometry, demonstrated a fast electron beam guiding phenomenon due to

Common-image gathers in the offset domain from reverse-time migration

KAUST Repository

Zhan, Ge

2014-04-01

Kirchhoff migration is flexible to output common-image gathers (CIGs) in the offset domain by imaging data with different offsets separately. These CIGs supply important information for velocity model updates and amplitude-variation-with-offset (AVO) analysis. Reverse-time migration (RTM) offers more insights into complex geology than Kirchhoff migration by accurately describing wave propagation using the two-way wave equation. But, it has difficulty to produce offset domain CIGs like Kirchhoff migration. In this paper, we develop a method for obtaining offset domain CIGs from RTM. The method first computes the RTM operator of an offset gather, followed by a dot product of the operator and the offset data to form a common-offset RTM image. The offset domain CIGs are then achieved after separately migrating data with different offsets. We generate offset domain CIGs on both the Marmousi synthetic data and 2D Gulf of Mexico real data using this approach. © 2014.

DFT-based offset-QAM OFDM for optical communications.

Science.gov (United States)

Zhao, Jian

2014-01-13

We experimentally demonstrate and numerically investigate a discrete-Fourier-transform (DFT) based offset quadrature-amplitude-modulation (offset-QAM) orthogonal frequency division multiplexing (OFDM) system. We investigate the scheme using a set of square-root-raised-cosine functions and a set of super-Gaussian functions as signal spectra. It is shown that offset-QAM OFDM exhibits negligible penalty for all investigated spectra, in contrast to rectangular-function based Nyquist FDM (N-FDM) and sinc-function based conventional OFDM (C-OFDM). The required guard interval (GI) length for dispersion compensation in offset-QAM OFDM is analyzed and shown to scale with twice the subcarrier spacing rather than the full OFDM bandwidth. Experimental results show that 38-Gb/s offset-16QAM OFDM supports 600-km fiber transmission with negligible penalty in the absence of GI while a GI length of eight is required in C-OFDM. Further numerical simulations show that by avoiding the GI, 112-Gb/s polarization multiplexed offset-4QAM OFDM can achieve 23% increase in net data rate over C-OFDM under the same transmission reach. We also discuss the design of the pulse-shaping filter in the DFT-based implementation and show that when compared to N-FDM, the required memory length of the filter for pulse shaping can be reduced from 60 to 2 in offset-QAM OFDM regardless of the fiber length.

Analytical model for fast-shock ignition

International Nuclear Information System (INIS)

Ghasemi, S. A.; Farahbod, A. H.; Sobhanian, S.

2014-01-01

A model and its improvements are introduced for a recently proposed approach to inertial confinement fusion, called fast-shock ignition (FSI). The analysis is based upon the gain models of fast ignition, shock ignition and considerations for the fast electrons penetration into the pre-compressed fuel to examine the formation of an effective central hot spot. Calculations of fast electrons penetration into the dense fuel show that if the initial electron kinetic energy is of the order ∼4.5 MeV, the electrons effectively reach the central part of the fuel. To evaluate more realistically the performance of FSI approach, we have used a quasi-two temperature electron energy distribution function of Strozzi (2012) and fast ignitor energy formula of Bellei (2013) that are consistent with 3D PIC simulations for different values of fast ignitor laser wavelength and coupling efficiency. The general advantages of fast-shock ignition in comparison with the shock ignition can be estimated to be better than 1.3 and it is seen that the best results can be obtained for the fuel mass around 1.5 mg, fast ignitor laser wavelength ∼0.3  micron and the shock ignitor energy weight factor about 0.25

Carbon offset potentials and design: Anticipating future public policy

International Nuclear Information System (INIS)

Trexler, M.C.; Kosloff, L.H.; Gowen, M.

1994-01-01

Carbon offsets offer CO 2 emitters the opportunity to compensate for some proportion of their CO 2 emissions through the pursuit of emissions reduction or carbon sequestration projects beyond their own operational boundaries. The flexibility to pursue carbon offsets ''off-site'' can dramatically reduce the costs of achieving a given net emissions reduction. The future role of carbon offsets, however, continues to be a topic of considerable debate. Several processes are currently under way nationally and internationally that will help shape this role. This paper discusses how alternative policy outcomes could encourage or restrict the viability of carbon offsets as a component of corporate climate change mitigation portfolios and proposes criteria by which projects should be evaluated prior to the finalization of national or international policy frameworks. Based on these outcomes, the potential for offsets could be very large or very modest. It is vital that policy development in the offset arena account for the still voluntary nature of mitigation efforts and that the objective of climate change mitigation not be forgotten in the push for offset rules and regulations. At the same time, carbon offsets are far from a panacea for climate change mitigation and should be evaluated in the context of a larger global mitigation portfolio

Biodiversity offsets and the challenge of achieving no net loss.

Science.gov (United States)

Gardner, Toby A; VON Hase, Amrei; Brownlie, Susie; Ekstrom, Jonathan M M; Pilgrim, John D; Savy, Conrad E; Stephens, R T Theo; Treweek, Jo; Ussher, Graham T; Ward, Gerri; Ten Kate, Kerry

2013-12-01

Businesses, governments, and financial institutions are increasingly adopting a policy of no net loss of biodiversity for development activities. The goal of no net loss is intended to help relieve tension between conservation and development by enabling economic gains to be achieved without concomitant biodiversity losses. biodiversity offsets represent a necessary component of a much broader mitigation strategy for achieving no net loss following prior application of avoidance, minimization, and remediation measures. However, doubts have been raised about the appropriate use of biodiversity offsets. We examined what no net loss means as a desirable conservation outcome and reviewed the conditions that determine whether, and under what circumstances, biodiversity offsets can help achieve such a goal. We propose a conceptual framework to substitute the often ad hoc approaches evident in many biodiversity offset initiatives. The relevance of biodiversity offsets to no net loss rests on 2 fundamental premises. First, offsets are rarely adequate for achieving no net loss of biodiversity alone. Second, some development effects may be too difficult or risky, or even impossible, to offset. To help to deliver no net loss through biodiversity offsets, biodiversity gains must be comparable to losses, be in addition to conservation gains that may have occurred in absence of the offset, and be lasting and protected from risk of failure. Adherence to these conditions requires consideration of the wider landscape context of development and offset activities, timing of offset delivery, measurement of biodiversity, accounting procedures and rule sets used to calculate biodiversity losses and gains and guide offset design, and approaches to managing risk. Adoption of this framework will strengthen the potential for offsets to provide an ecologically defensible mechanism that can help reconcile conservation and development. Balances de Biodiversidad y el Reto de No Obtener P�

How economic contexts shape calculations of yield in biodiversity offsetting.

Science.gov (United States)

Carver, L; Sullivan, S

2017-10-01

We examined and analyzed methods used to create numerical equivalence between sites affected by development and proposed conservation offset sites. Application of biodiversity offsetting metrics in development impact and mitigation assessments is thought to standardize biodiversity conservation outcomes, sometimes termed yield by those conducting these calculations. The youth of biodiversity offsetting in application, however, means little is known about how biodiversity valuations and offset contracts between development and offset sites are agreed on in practice or about long-term conservation outcomes. We examined how sites were made commensurable and how biodiversity gains or yields were calculated and negotiated for a specific offset contract in a government-led pilot study of biodiversity offsets in England. Over 24 months, we conducted participant observations of various stages in the negotiation of offset contracts through repeated visits to 3 (anonymized) biodiversity offset contract sites. We conducted 50 semistructured interviews of stakeholders in regional and local government, the private sector, and civil society. We used a qualitative data analysis software program (DEDOOSE) to textually analyze interview transcriptions. We also compared successive iterations of biodiversity-offsetting calculation spreadsheets and planning documents. A particular focus was the different iterations of a specific biodiversity impact assessment in which the biodiversity offsetting metric developed by the U.K.'s Department for Environment, Food and Rural Affairs was used. We highlight 3 main findings. First, biodiversity offsetting metrics were amended in creative ways as users adapted inputs to metric calculations to balance and negotiate conflicting requirements. Second, the practice of making different habitats equivalent to each other through the application of biodiversity offsetting metrics resulted in commensuration outcomes that may not provide projected

5 CFR 179.213 - Coordinating salary offset with other agencies.

Science.gov (United States)

2010-01-01

... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Coordinating salary offset with other... REGULATIONS CLAIMS COLLECTION STANDARDS Salary Offset § 179.213 Coordinating salary offset with other agencies... intent of this regulation. (2) The designated salary offset coordinator will be responsible for: (i...

The Effect of Allowing Pollution Offsets with Imperfect Enforcement

OpenAIRE

Hilary Sigman; Howard F. Chang

2011-01-01

Public policies for pollution control, including climate change policies, sometimes allow polluters in one sector subject to an emissions cap to offset excessive emissions in that sector with pollution abatement in another sector. The government may often find it more costly to verify offset claims than to verify compliance with emissions caps. Concerns about such difficulties in enforcement may lead regulators to restrict the use of offsets. In this paper, we demonstrate that allowing offset...

Kinetic Simulation of Fast Electron Transport with Ionization Effects and Ion Acceleration

International Nuclear Information System (INIS)

Robinson, A. P. L.; Bell, A. R.; Kingham, R. J.

2005-01-01

The generation of relativistic electrons and multi-MeV ions is central to ultra intense (> 1018Wcm-2) laser-solid interactions. The production of energetic particles by lasers has a number of potential applications ranging from Fast Ignition ICF to medicine. In terms of the relativistic (fast) electrons the areas of interest can be divided into three areas. Firstly there is the absorption of laser energy into fast electrons and MeV ions. Secondly there is the transport of fast electrons through the solid target. Finally there is a transduction stage, where the fast electron energy is imparted. This may range from being the electrostatic acceleration of ions at a plasma-vacuum interface, to the heating of a compressed core (as in Fast Ignitor ICF).We have used kinetic simulation codes to study the transport stage and electrostatic ion acceleration. (Author)

The development of laser fusion research

Energy Technology Data Exchange (ETDEWEB)

Mima, Kunioki [Osaka Univ., Suita (Japan). Inst. of Laser Engineering

1998-11-01

Laser fusion research started soon after the invention of laser. In 1972, the research was declassified and nuclear fusion by laser inplosion was proposed by J. Nuckolls. Since then, 26 years has passed and laser implosion experiments demonstrated 1000 times solid density compression. By the demonstration of 1000 times solid density, the mission of the laser fusion research shifted from `implosion physics` to `ignition and high gain`, namely demonstration of fusion output of 100 times input laser energy. By the recent developments of laser technology, ultra intense laser became available and opened up a new ignition scheme which is called `Fast Ignition`. The technology for the diode pumped solid state laser (DPSSL) is developed toward a laser driver for reactor. U.S. and France are constructing MJ lasers for demonstrating ignition and burn and Osaka University is investigating the fast ignition and the equivalent plasma of confinement (EPOC) toward high gain. (author)

The development of laser fusion research

International Nuclear Information System (INIS)

Mima, Kunioki

1998-01-01

Laser fusion research started soon after the invention of laser. In 1972, the research was declassified and nuclear fusion by laser inplosion was proposed by J. Nuckolls. Since then, 26 years has passed and laser implosion experiments demonstrated 1000 times solid density compression. By the demonstration of 1000 times solid density, the mission of the laser fusion research shifted from 'implosion physics' to 'ignition and high gain', namely demonstration of fusion output of 100 times input laser energy. By the recent developments of laser technology, ultra intense laser became available and opened up a new ignition scheme which is called 'Fast Ignition'. The technology for the diode pumped solid state laser (DPSSL) is developed toward a laser driver for reactor. U.S. and France are constructing MJ lasers for demonstrating ignition and burn and Osaka University is investigating the fast ignition and the equivalent plasma of confinement (EPOC) toward high gain. (author)

Offset Compound Gear Drive

Science.gov (United States)

Stevens, Mark A.; Handschuh, Robert F.; Lewicki, David G.

2010-01-01

The Offset Compound Gear Drive is an in-line, discrete, two-speed device utilizing a special offset compound gear that has both an internal tooth configuration on the input end and external tooth configuration on the output end, thus allowing it to mesh in series, simultaneously, with both a smaller external tooth input gear and a larger internal tooth output gear. This unique geometry and offset axis permits the compound gear to mesh with the smaller diameter input gear and the larger diameter output gear, both of which are on the same central, or primary, centerline. This configuration results in a compact in-line reduction gear set consisting of fewer gears and bearings than a conventional planetary gear train. Switching between the two output ratios is accomplished through a main control clutch and sprag. Power flow to the above is transmitted through concentric power paths. Low-speed operation is accomplished in two meshes. For the purpose of illustrating the low-speed output operation, the following example pitch diameters are given. A 5.0 pitch diameter (PD) input gear to 7.50 PD (internal tooth) intermediate gear (0.667 reduction mesh), and a 7.50 PD (external tooth) intermediate gear to a 10.00 PD output gear (0.750 reduction mesh). Note that it is not required that the intermediate gears on the offset axis be of the same diameter. For this example, the resultant low-speed ratio is 2:1 (output speed = 0.500; product of stage one 0.667 reduction and stage two 0.750 stage reduction). The design is not restricted to the example pitch diameters, or output ratio. From the output gear, power is transmitted through a hollow drive shaft, which, in turn, drives a sprag during which time the main clutch is disengaged.

12 CFR 313.49 - Coordinating salary offset with other agencies.

Science.gov (United States)

2010-01-01

... 12 Banks and Banking 4 2010-01-01 2010-01-01 false Coordinating salary offset with other agencies... PRACTICE PROCEDURES FOR CORPORATE DEBT COLLECTION Salary Offset § 313.49 Coordinating salary offset with... employee has consented to the salary offset in writing or has signed a statement acknowledging receipt of...

Southern San Andreas Fault evaluation field activity: approaches to measuring small geomorphic offsets--challenges and recommendations for active fault studies

Science.gov (United States)

Scharer, Katherine M.; Salisbury, J. Barrett; Arrowsmith, J. Ramon; Rockwell, Thomas K.

2014-01-01

In southern California, where fast slip rates and sparse vegetation contribute to crisp expression of faults and microtopography, field and high‐resolution topographic data (fault, analyze the offset values for concentrations or trends along strike, and infer that the common magnitudes reflect successive surface‐rupturing earthquakes along that fault section. Wallace (1968) introduced the use of such offsets, and the challenges in interpreting their “unique complex history” with offsets on the Carrizo section of the San Andreas fault; these were more fully mapped by Sieh (1978) and followed by similar field studies along other faults (e.g., Lindvall et al., 1989; McGill and Sieh, 1991). Results from such compilations spurred the development of classic fault behavior models, notably the characteristic earthquake and slip‐patch models, and thus constitute an important component of the long‐standing contrast between magnitude–frequency models (Schwartz and Coppersmith, 1984; Sieh, 1996; Hecker et al., 2013). The proliferation of offset datasets has led earthquake geologists to examine the methods and approaches for measuring these offsets, uncertainties associated with measurement of such features, and quality ranking schemes (Arrowsmith and Rockwell, 2012; Salisbury, Arrowsmith, et al., 2012; Gold et al., 2013; Madden et al., 2013). In light of this, the Southern San Andreas Fault Evaluation (SoSAFE) project at the Southern California Earthquake Center (SCEC) organized a combined field activity and workshop (the “Fieldshop”) to measure offsets, compare techniques, and explore differences in interpretation. A thorough analysis of the measurements from the field activity will be provided separately; this paper discusses the complications presented by such offset measurements using two channels from the San Andreas fault as illustrative cases. We conclude with best approaches for future data collection efforts based on input from the Fieldshop.

Quadrupole to BPM offset determination in Indus-2

International Nuclear Information System (INIS)

Jena, Saroj; Ghodke, A.D.; Singh, G.

2009-01-01

A feasibility of finding the quadrupole to BPM offset using beam based alignment (BBA) technique in Indus-2 has been studied. The measurements of the offsets between BPM and quadrupoles could be performed by using quadratic fitting for the minima of the orbit response w. r. t. changes in the quadrupole strengths. These offsets will be integrated to the orbit data during closed orbit correction. There are 72 quadrupoles and 56 BPMs in Indus-2. However the assessment of Quad-BPM offsets is not feasible in some cases due to non-availability of BPM adjacent to quadrupole and also in some cases because of a large phase advance between quadrupole and nearby BPM. Here single corrector method is used to obtain these offsets and assumed the current of each quadrupole can be varied independently. A graphical user interface (GUI) is developed in MATLAB for the use of BBA in Indus-2. (author)

Nuclear Ground State Properties in Strontium by Fast Beam Laser Spectroscopy

CERN Multimedia

2002-01-01

Hyperfine structures and isotope shifts of strontium isotopes with A=78 to A=100 were measured by collinear fast beam laser spectroscopy. Nuclear spins, moments and changes in mean square charge radii are extracted from the data. The spins and moments of most of the odd isotopes are explained in the framework of the single particle model. The changes in mean square charge radii show a decrease with increasing neutron number below the N=50 shell closure. Above N=50 the charge radii increase regularly up to N=59 before revealing a strong discontinuity, indicating the onset of strong ground state deformation. A comparison of the droplet model shows that for the transitional isotopes below and above N=50, the zero point quadrupole motion describes part of the observed shell effect. Calculations carried out in the Hartree-Fock plus BCS model suggest an additional change in the surface region of the charge distribution at spherical shape. From these calculations it is furthermore proposed, that the isotopes $^7

Cancellation of birefringence in DBR laser through principal axis offset by a rotation of 90°

Science.gov (United States)

Zaini, M. K. A.; Lai, M. H.; Islam, M. R.; Lim, K. S.; Ahmad, H.

2018-04-01

The cancellation of birefringence in the distributed Bragg reflector based on 90° rotation offset method is demonstrated. It is found that the birefringence, which causes the peak bifurcation has been eliminated and a single peak is produced at each resonance in the output spectrum. This modification is an economic solution for eliminating the birefringence of the optical fibre devices.

15 CFR 19.10 - How will Commerce entities use administrative offset (offset of non-tax Federal payments) to...

Science.gov (United States)

2010-01-01

... 15 Commerce and Foreign Trade 1 2010-01-01 2010-01-01 false How will Commerce entities use administrative offset (offset of non-tax Federal payments) to collect a Commerce debt? 19.10 Section 19.10 Commerce and Foreign Trade Office of the Secretary of Commerce COMMERCE DEBT COLLECTION Procedures To...

Snap Down Voltage of a Fast-Scanning Micromirror with Vertical Electrostatic Combdrives

Science.gov (United States)

Wada, Hiroyuki; Lee, Daesung; Zappe, Stefan; Krishnamoorthy, Uma; Solgaard, Olav

2004-02-01

The parallel transition mode of the snap down of a fast-scanning mirror with vertical combdrives was analyzed. The snap down voltage of such a mirror significantly decreased when offsets between the ideal and actual upper movable comb teeth were more than 0.1 μm. When gap between the upper and lower comb teeth was decreased to increase torque, snap down voltage significantly decreased. The largest offset is induced by the lithography step in the fabrication process of the mirror. Self-alignment is required to increase the resonant frequency of the scanning mirror.

Time-resolved diagnostics of excimer laser-generated ablation plasmas used for pulsed laser deposition

Energy Technology Data Exchange (ETDEWEB)

Geohegan, D.B.

1994-09-01

Characteristics of laser plasmas used for pulsed laser deposition (PLD) of thin films are examined with four in situ diagnostic techniques: Optical emission spectroscopy, optical absorption spectroscopy, ion probe studies, and gated ICCD (intensified charge-coupled-device array) fast photography. These four techniques are complementary and permit simultaneous views of the transport of ions, excited states, ground state neutrals and ions, and hot particulates following KrF laser ablation of YBCO, BN, graphite and Si in vacuum and background gases. The implementation and advantages of the four techniques are first described in order to introduce the key features of laser plasmas for pulsed laser deposition. Aspects of the interaction of the ablation plume with background gases (i.e., thermalization, attenuation, shock formation) and the collision of the plasma plume with the substrate heater are then summarized. The techniques of fast ICCD photography and gated photon counting are then applied to investigate the temperature, velocity, and spatial distribution of hot particles generated during KrF ablation of YBCO, BN, Si and graphite. Finally, key features of fast imaging of the laser ablation of graphite into high pressure rare gases are presented in order to elucidate internal reflected shocks within the plume, redeposition of material on a surface, and formation of hot nanoparticles within the plume.

Time-resolved diagnostics of excimer laser-generated ablation plasmas used for pulsed laser deposition

International Nuclear Information System (INIS)

Geohegan, D.B.

1994-01-01

Characteristics of laser plasmas used for pulsed laser deposition (PLD) of thin films are examined with four in situ diagnostic techniques: Optical emission spectroscopy, optical absorption spectroscopy, ion probe studies, and gated ICCD (intensified charge-coupled-device array) fast photography. These four techniques are complementary and permit simultaneous views of the transport of ions, excited states, ground state neutrals and ions, and hot particulates following KrF laser ablation of YBCO, BN, graphite and Si in vacuum and background gases. The implementation and advantages of the four techniques are first described in order to introduce the key features of laser plasmas for pulsed laser deposition. Aspects of the interaction of the ablation plume with background gases (i.e., thermalization, attenuation, shock formation) and the collision of the plasma plume with the substrate heater are then summarized. The techniques of fast ICCD photography and gated photon counting are then applied to investigate the temperature, velocity, and spatial distribution of hot particles generated during KrF ablation of YBCO, BN, Si and graphite. Finally, key features of fast imaging of the laser ablation of graphite into high pressure rare gases are presented in order to elucidate internal reflected shocks within the plume, redeposition of material on a surface, and formation of hot nanoparticles within the plume

Offset Trace-Based Video Quality Evaluation Network Transport

DEFF Research Database (Denmark)

Seeling, P.; Reisslein, M.; Fitzek, Frank

2006-01-01

Video traces contain information about encoded video frames, such as frame sizes and qualities, and provide a convenient method to conduct multimedia networking research. Although wiedely used in networking research, these traces do not allow to determine the video qaulityin an accurate manner...... after networking transport that includes losses and delays. In this work, we provide (i) an overview of frame dependencies that have to be taken into consideration when working with video traces, (ii) an algorithmic approach to combine traditional video traces and offset distortion traces to determine...... the video quality or distortion after lossy network transport, (iii) offset distortion and quality characteristics and (iv) the offset distortion trace format and tools to create offset distortion traces....

10 CFR 16.15 - Procedures for internal salary offset.

Science.gov (United States)

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Procedures for internal salary offset. 16.15 Section 16.15 Energy NUCLEAR REGULATORY COMMISSION SALARY OFFSET PROCEDURES FOR COLLECTING DEBTS OWED BY FEDERAL EMPLOYEES TO THE FEDERAL GOVERNMENT § 16.15 Procedures for internal salary offset. (a) Deductions to...

Developing the Physics Basis of Fast Ignition Experiments at Future Large Fusion-class lasers

International Nuclear Information System (INIS)

Mackinnon, A J; Key, M H; Hatchett, S; MacPhee, A G; Foord, M; Tabak, M; Town, R J; Patel, P K

2008-01-01

The Fast Ignition (FI) concept for Inertial Confinement Fusion (ICF) has the potential to provide a significant advance in the technical attractiveness of Inertial Fusion Energy (IFE) reactors. FI differs from conventional 'central hot spot' (CHS) target ignition by using one driver (laser, heavy ion beam or Z-pinch) to create a dense fuel and a separate ultra-short, ultra-intense laser beam to ignite the dense core. FI targets can burn with ∼ 3X lower density fuel than CHS targets, resulting in (all other things being equal) lower required compression energy, relaxed drive symmetry, relaxed target smoothness tolerances, and, importantly, higher gain. The short, intense ignition pulse that drives this process interacts with extremely high energy density plasmas; the physics that controls this interaction is only now becoming accessible in the lab, and is still not well understood. The attraction of obtaining higher gains in smaller facilities has led to a worldwide explosion of effort in the studies of FI. In particular, two new US facilities to be completed in 2009/2010, OMEGA/OMEGA EP and NIF-ARC (as well as others overseas) will include FI investigations as part of their program. These new facilities will be able to approach FI conditions much more closely than heretofore using direct drive (dd) for OMEGA/OMEGA EP and indirect drive (id) for NIF-ARC. This LDRD has provided the physics basis for the development of the detailed design for integrated Fast ignition experiments on these facilities on the 2010/2011 timescale. A strategic initiative LDRD has now been formed to carry out integrated experiments using NIF ARC beams to heat a full scale FI assembled core by the end of 2010

Raman fiber distributed feedback lasers.

Science.gov (United States)

Westbrook, Paul S; Abedin, Kazi S; Nicholson, Jeffrey W; Kremp, Tristan; Porque, Jerome

2011-08-01

We demonstrate fiber distributed feedback (DFB) lasers using Raman gain in two germanosilicate fibers. Our DFB cavities were 124 mm uniform fiber Bragg gratings with a π phase shift offset from the grating center. Our pump was at 1480 nm and the DFB lasers operated on a single longitudinal mode near 1584 nm. In a commercial Raman gain fiber, the maximum output power, linewidth, and threshold were 150 mW, 7.5 MHz, and 39 W, respectively. In a commercial highly nonlinear fiber, these figures improved to 350 mW, 4 MHz, and 4.3 W, respectively. In both lasers, more than 75% of pump power was transmitted, allowing for the possibility of substantial amplification in subsequent Raman gain fiber. © 2011 Optical Society of America

Buying a laser - Tips and pearls

Directory of Open Access Journals (Sweden)

Sanjeev J Aurangabadkar

2014-01-01

Meticulous planning of the type of machine, specifications, financial aspects, maintenance and warranties is important.It is wise to sign a contract or agreement between the buyer and seller before purchase of a laser which covers key aspects of installation, after sales service and maintenance of the machine.Adequate training is essential; understanding laser physics and laser-tissue interaction goes a long way in getting the best out of the machine.The credibility of the dealer and company should be ascertained in order to be assured of after-sales service.Buying used machines, sharing of equipment to offset high initial investments is a good option but even more care is required to ensure proper functioning and maintenance.

Achieving biodiversity benefits with offsets: Research gaps, challenges, and needs.

Science.gov (United States)

Gelcich, Stefan; Vargas, Camila; Carreras, Maria Jose; Castilla, Juan Carlos; Donlan, C Josh

2017-03-01

Biodiversity offsets are becoming increasingly common across a portfolio of settings: national policy, voluntary programs, international lending, and corporate business structures. Given the diversity of ecological, political, and socio-economic systems where offsets may be applied, place-based information is likely to be most useful in designing and implementing offset programs, along with guiding principles that assure best practice. We reviewed the research on biodiversity offsets to explore gaps and needs. While the peer-reviewed literature on offsets is growing rapidly, it is heavily dominated by ecological theory, wetland ecosystems, and U.S.-based research. Given that majority of offset policies and programs are occurring in middle- and low-income countries, the research gaps we identified present a number of risks. They also present an opportunity to create regionally based learning platforms focused on pilot projects and institutional capacity building. Scientific research should diversify, both topically and geographically, in order to support the successful design, implementation, and monitoring of biodiversity offset programs.

Multi-analysis and modeling of asymmetry offset for Hall effect structures

Energy Technology Data Exchange (ETDEWEB)

Paun, Maria-Alexandra, E-mail: maria_paun2003@yahoo.com

2017-03-15

The topological (asymmetry) offset voltage of CMOS cross-like Hall cells is analyzed in this paper. In order to attain the stated objective, different approaches have been considered. Both circuit and three-dimensional models have been developed. Variation of the misalignment offset with the biasing current has been studied through physical and circuit models. The latter is a non-homogenous finite elements model, which relies on using parameterized resistances and current-controlled current sources, of CMOS Hall cells. The displacement offset for various asymmetries and the offset variation with the temperature were investigated through the circuit model developed. Various experimental results for the single and magnetic equivalent offset have also been provided. - Highlights: • In this paper both physical and circuit models have been proposed for the evaluation of Hall cells offset. • Variation of the misalignment offset with the biasing current has been studied. • The displacement offset for various asymmetries and the offset variation with the temperature were investigated. • Various experimental results for single and magnetic equivalent offset were provided. • The obtained simulation results are in accordance with the experimental data.

An intercomparison of the thermal offset for different pyranometers

Science.gov (United States)

Sanchez, G.; Cancillo, M. L.; Serrano, A.

2016-07-01

An unprecedented intensive intercomparison campaign focused on the experimental measurement of the thermal offset of pyranometers has been conducted at Badajoz (Spain) with the participation of three main manufacturers. The purpose of this study is to compare the thermal offset of six commercially available pyranometers, being some of them widely used and others recently commercialized. In this campaign, the capping methodology has been used to experimentally measure the daytime thermal offset of the pyranometers. Thus, a short but intense campaign has been conducted in two selected summer days under clear-sky conditions, covering a large range of solar zenith angle, irradiance, and temperature. Along the campaign, a total of 305 capping events have been performed, 61 for each pyranometer. The daytime thermal offset obtained for different pyranometers ranges between 0 and -16.8 W/m2 depending on the environmental conditions, being sometimes notably higher than values estimated indoors by manufacturers. The thermal offset absolute value of all instruments shows a diurnal cycle, increasing from sunrise to central hours of the day and decreasing from midafternoon to sunset. The analysis demonstrates that thermal offset is notably higher and more variable during daytime than during nighttime, requiring specific daytime measurements. Main results emphasize the key role played by wind speed in modulating the thermal offset.

Channel estimation in DFT-based offset-QAM OFDM systems.

Science.gov (United States)

Zhao, Jian

2014-10-20

Offset quadrature amplitude modulation (offset-QAM) orthogonal frequency division multiplexing (OFDM) exhibits enhanced net data rates compared to conventional OFDM, and reduced complexity compared to Nyquist FDM (N-FDM). However, channel estimation in discrete-Fourier-transform (DFT) based offset-QAM OFDM is different from that in conventional OFDM and requires particular study. In this paper, we derive a closed-form expression for the demultiplexed signal in DFT-based offset-QAM systems and show that although the residual crosstalk is orthogonal to the decoded signal, its existence degrades the channel estimation performance when the conventional least-square method is applied. We propose and investigate four channel estimation algorithms for offset-QAM OFDM that vary in terms of performance, complexity, and tolerance to system parameters. It is theoretically and experimentally shown that simple channel estimation can be realized in offset-QAM OFDM with the achieved performance close to the theoretical limit. This, together with the existing advantages over conventional OFDM and N-FDM, makes this technology very promising for optical communication systems.

Sample Adaptive Offset Optimization in HEVC

Directory of Open Access Journals (Sweden)

Yang Zhang

2014-11-01

Full Text Available As the next generation of video coding standard, High Efficiency Video Coding (HEVC adopted many useful tools to improve coding efficiency. Sample Adaptive Offset (SAO, is a technique to reduce sample distortion by providing offsets to pixels in in-loop filter. In SAO, pixels in LCU are classified into several categories, then categories and offsets are given based on Rate-Distortion Optimization (RDO of reconstructed pixels in a Largest Coding Unit (LCU. Pixels in a LCU are operated by the same SAO process, however, transform and inverse transform makes the distortion of pixels in Transform Unit (TU edge larger than the distortion inside TU even after deblocking filtering (DF and SAO. And the categories of SAO can also be refined, since it is not proper for many cases. This paper proposed a TU edge offset mode and a category refinement for SAO in HEVC. Experimental results shows that those two kinds of optimization gets -0.13 and -0.2 gain respectively compared with the SAO in HEVC. The proposed algorithm which using the two kinds of optimization gets -0.23 gain on BD-rate compared with the SAO in HEVC which is a 47 % increase with nearly no increase on coding time.

High-power direct diode laser output by spectral beam combining

Science.gov (United States)

Tan, Hao; Meng, Huicheng; Ruan, Xu; Du, Weichuan; Wang, Zhao

2018-03-01

We demonstrate a spectral beam combining scheme based on multiple mini-bar stacks, which have more diode laser combining elements, to increase the combined diode laser power and realize equal beam quality in both the fast and slow axes. A spectral beam combining diode laser output of 1130 W is achieved with an operating current of 75 A. When a 9.6 X de-magnifying telescope is introduced between the output mirror and the diffraction grating, to restrain cross-talk among diode laser emitters, a 710 W spectral beam combining diode laser output is achieved at the operating current of 70 A, and the beam quality on the fast and slow axes of the combined beam is about 7.5 mm mrad and 7.3 mm mrad respectively. The power reduction is caused by the existence of a couple resonator between the rear facet of the diode laser and the fast axis collimation lens, and it should be eliminated by using diode laser chips with higher front facet transmission efficiency and a fast axis collimation lens with lower residual reflectivity.

The future of the Fast Breeder

International Nuclear Information System (INIS)

Lefevre, J.C.

1990-01-01

Fast Breeder Reactors (FBRs) can produce more fissile nuclei than they consume whilst, at the same time, generating energy using fast neutrons. By conversion of uranium isotope 238 into a fissionable fuel, FBRs provide over 60 times more energy than can be extracted from the uranium reserves by thermal reactors. Their development is therefore an essential objective in the next century, particularly for those industrialised countries that have little or no energy resources of their own. The European countries which have been engaged in the development of FBRs for more than 25 years have decided to collaborate in an advanced design, the European Fast Reactor (EFR) which uses the best of previous national projects and draws on extensive operating experience from FBR plants in Europe. The naturally safe characteristics and technological features of sodium-cooled Fast Reactors will be fully utilised in an EFR design which meets the same safety level as the Light Water Reactors (LWRs). Owing to technical progress and series construction effect, the EFR is expected to achieve competitiveness with contemporary LWRs with the higher capital cost of the Fast Reactor offset by its markedly lower fuel cycle cost. (author)

Ultrafast photoconductor detector-laser-diode transmitter

International Nuclear Information System (INIS)

Wang, C.L.; Davis, B.A.; Davies, T.J.; Nelson, M.A.; Thomas, M.C.; Zagarino, P.A.

1987-01-01

We report the results of an experiment in which we used an ultrafast, photoconductive, radiation detector to drive a fast laser-diode transmitter. When we irradiated the neutron-damaged Cr-doped GaAs detector with 17-MeV electron beams, the temporal response was measured to be less than 30 ps. The pulses from this detector modulated a fast GaAlAs laser diode to transmit the laser output through 30- and 1100-m optical fibers. Preliminary results indicate that 50- and 80-ps time resolutions, respectively, are obtainable with these fibers. We are now working to integrate the photoconductive detector and the laser diode transmitter into a single chip

KrF lasers as inertial fusion drivers

International Nuclear Information System (INIS)

Harris, D.B.; Berggren, R.R.; Kurnit, N.A.; Lowenthal, D.D.; Berger, R.G.; Eggleston, J.M.; Ewing, J.J.; Kushner, M.J.

1986-01-01

A new type of KrF laser system has been proposed that has a significantly higher efficiency than pure angular multiplexed KrF lasers. This system uses electron-beam-sustained discharge lasers to pump a high gain Raman amplifier. The discharge lasers can operate at a higher efficiency than e-beam pumped lasers, and the forward Raman scattering process has both a high gain and high quantum efficiency using the rotational transition. The Raman system cost and performance has been examined and compared to the pure angular multiplexed system. The discharge-Raman system has a higher efficiency (12% vs 9%) and a higher cost ($140/joule vs $100/joule). For an ICF power plant driver, the higher efficiency offsets the higher cost, making the discharge-Raman system appear to be an attractive alternative to the pure angular multiplexed system

KrF lasers as inertial fusion drivers

International Nuclear Information System (INIS)

Harris, D.B.; Berggren, R.R.; Kurnit, N.A.; Lowenthal, D.D.; Berger, R.G.; Eggleston, J.M.; Ewing, J.J.; Kushner, M.J.

1985-01-01

A new type of KrF laser system has been proposed that has a significantly higher efficiency than pure angular multiplexed KrF lasers. This system uses electron-beam-sustained discharge lasers to pump a high gain Raman amplifier. The discharge lasers can operate at a higher efficiency than e-beam pumped lasers, and the forward Raman scattering process has both a high gain and high quantum efficiency using the rotational transition. The Raman system cost and performance has been examined and compared to the pure angular multiplexed system. The discharge-Raman system has a higher efficiency (12.3% vs 9.1%) and a higher cost ($140/joule vs $100/joule). For an ICF power plant driver, the higher efficiency offsets the higher cost, making the discharge-Raman system appear to be an attractive alternative to the pure angular multiplexed system

Handbook of Carbon Offset Programs. Trading Systems, Funds, Protocols and Standards

Energy Technology Data Exchange (ETDEWEB)

Kollmuss, Anja; Lazarus, Michael; Lee, Carrie; Polycarp, Clifford (SEI-US (United States)); LeFranc, Maurice (US EPA (United States))

2010-03-15

Greenhouse gas (GHG) offsets have long been promoted as an important element of a comprehensive climate policy approach. Offset programs can reduce the overall cost of achieving a given emission goal by enabling emission reductions to occur where costs are lower. Offsets have the potential to deliver sustainability co-benefits, through technology development and transfer. They can also develop human and institutional capacity for reducing emissions in sectors and locations not included in a cap and trade or a mandatory government policy. However, offsets can pose a risk to the environmental integrity of climate actions, especially if issues surrounding additionality, permanence, leakage, quantification and verification are not adequately addressed. The challenge is to design offset programs and policies that can maximize their potential benefits while minimizing their potential risks. This handbook provides a systematic and comprehensive review of existing offset programs. It looks are what offsets are, how offset mechanisms function, and the successes and pitfalls they have encountered. Coverage includes offset programs across the full swath of applications including mandatory and voluntary systems, government regulated and private markets, carbon offset funds, and accounting and reporting protocols such as the WBCSD/WRI GHG Protocol and ISO 14064. Learning from the successes and failures of these programs will be essential to crafting effective climate policy. A reference for regulators, policy makers, business leaders and NGOs concerned with the design and operation of GHG offset programs world-wide

Relationship between acoustic voice onset and offset and selected instances of oscillatory onset and offset in young healthy males and females

Science.gov (United States)

Patel, Rita; Forrest, Karen; Hedges, Drew

2016-01-01

Objective To investigate the relationship between (1) onset of the acoustic signal and pre-phonatory phases associated with oscillatory onset and (2) offset of the acoustic signal with the post-phonatory events associated with oscillatory offset across vocally healthy adults. Subjects and Methods High-speed videoendoscopy was captured simultaneously with the acoustic signal during repeated production of /hi.hi.hi/ at typical pitch and loudness from 56 vocally healthy adults (age 20–42 years; 21 male, 35 female). The relationship between the acoustic sound pressure signal and oscillatory onset /offset events from the glottal area waveforms (GAW), were statistically investigated using a multivariate linear regression analysis. Results The onset of the acoustic signal (X1a) is a significant predictor of the onset of first oscillations (X1g) and onset of sustained oscillations (X2g). X1a as well as gender are significant predictors of the first instance of medial contact (X1.5g). The offset of the acoustic signal (X2a) is a significant predictor of the first instance of oscillatory offset (X3g), first instance of incomplete glottal closure (X3.5g), and cessation of vocal fold motion (X4g). Conclusions The acoustic signal onset is closely related to the first medial contact of the vocal folds but the latency between these events is longer for females compared to males. The offset of the acoustic signal occurs immediately after incomplete glottal adduction. The emerging normative group latencies between the onset/offset of the acoustic and the GAW from this study appear promising for future investigations. PMID:27769696

Plasma Channel Diagnostic Based on Laser Centroid Oscillations

International Nuclear Information System (INIS)

Gonsalves, Anthony; Nakamura, Kei; Lin, Chen; Osterhoff, Jens; Shiraishi, Satomi; Schroeder, Carl; Geddes, Cameron; Toth, Csaba; Esarey, Eric; Leemans, Wim

2010-01-01

A technique has been developed for measuring the properties of discharge-based plasma channels by monitoring the centroid location of a laser beam exiting the channel as a function of input alignment offset between the laser and the channel. The centroid position of low-intensity ( 14 Wcm -2 ) laser pulses focused at the input of a hydrogen-filled capillary discharge waveguide was scanned and the exit positions recorded to determine the channel shape and depth with an accuracy of a few %. In addition, accurate alignment of the laser beam through the plasma channel can be provided by minimizing laser centroid motion at the channel exit as the channel depth is scanned either by scanning the plasma density or the discharge timing. The improvement in alignment accuracy provided by this technique will be crucial for minimizing electron beam pointing errors in laser plasma accelerators.

Research on Stress Neutral Layer Offset in the Straightening Process

Directory of Open Access Journals (Sweden)

Hailian Gui

2015-01-01

Full Text Available The stress neutral layer offset is analyzed by theoretical and numerical calculation methods. In traditional straightening theory, the stress neutral layer was consistent with the geometric central layer. However, there is a phenomenon that the stress neutral layer has some offset with the geometric neutral layer. This offset is a very important factor for improving the precision of the straightening force. The formula of the stress neutral layer offset is obtained by a theoretical method and the change law is given by numerical calculation method. The neutral layer offset theory provides the theoretical basis for establishing the model of straightening force precisely.

Experimental study of fast electron transport and of the propagation of shock waves generated by laser in the framework of inertial fusion

International Nuclear Information System (INIS)

Sakaki, T.

2016-01-01

This document presents 3 experiments carried out within the framework of inertial fusion. The first experiment was devoted to the study of fast electron beam transport in a compressed target. The implosion of the target with a cylindrical geometry was carried out with the GEKKO XII laser facility (ILE Osaka, Japan). The fast electron beam was generated by the LFEX laser (∼10"1"9 W/cm"2) and its propagation through the compressed cylinder was observed with several X-ray diagnostics. This experiment showed the guiding effect of the electron beam resulting from self-generated magnetic fields. Furthermore, the results of this experiment were in good agreement with numerical simulations. Two other experiments were performed to study the propagation of strong shock waves created by lasers in a plasma. They were carried out with different laser systems. In the first experiment with the Gekko XII laser, we observed the creation and the propagation of two successive shock waves in an ablation plasma in CH and Be. The objective of characterizing the amplification of a transmitted shock by the collision of two counter-propagating shocks has been partially realized. The comparison of the experimental results with the hydrodynamic simulations enabled us to confirm an amplification of the shock by a factor 2 in pressure in the condition of this experiment. The shot with a Be target allowed the development and validation of the diagnostic method of X-ray radiography for shock wave propagation. The second experiment was performed with PHELIX GSI laser (Darmstadt, Germany). The purpose of this experiment was to study the generation of strong shocks. They were applied to study the equation of state of carbon in the WDM state. The condition of pressure and density for the carbon were obtained by deducing the pressure and the velocity of the shock wave chronometric diagnostics employed in this experiment. In this experiment, diamond was at the metallic liquid phase with a pressure

Characteristics and structure of turbulent 3D offset jets

International Nuclear Information System (INIS)

Agelin-Chaab, M.; Tachie, M.F.

2011-01-01

Highlights: → We investigated three-dimensional turbulent offset jets using particle image velocimetry. → We examined the effects of offset height and Reynolds number on the structure of 3D offset jets. → Effects of Reynolds number and offset height on the decay and growth rates exist close to the exit. → This study provides additional insight and comprehensive data for validating numerical models. - Abstract: Three-dimensional turbulent offset jets were investigated using a particle image velocimetry technique. The measurements were performed at three different exit Reynolds numbers and for four offset heights. The results in the early region of flow development clearly show significant effects of Reynolds number and offset height on the decay of maximum mean velocity and growth of the shear layer. On the contrary, the decay and spread rates were found to be nearly independent of offset height at larger downstream distances. The decay rates of 1.18 ± 0.03 as well as the spread rates of 0.055 ± 0.001 and 0.250 ± 0.005 obtained, respectively, in the wall-normal and lateral directions fall in the range of values reported in previous studies. The locations of the maximum mean velocities increased nearly linearly with streamwise distance in the self-similar region. Analysis from two-point velocity correlations revealed substantially larger structures in the outer layer and self-similar region than in the inner layer and developing region. It was also observed that the hairpin vortices in the inner regions of the wall jets are inclined at angles of 11.2 o ± 0.6 o , which are in good agreement with reported values in boundary layer studies.

Application of Gaussian beam ray-equivalent model and back-propagation artificial neural network in laser diode fast axis collimator assembly.

Science.gov (United States)

Yu, Hao; Rossi, Giammarco; Braglia, Andrea; Perrone, Guido

2016-08-10

The paper presents the development of a tool based on a back-propagation artificial neural network to assist in the accurate positioning of the lenses used to collimate the beam from semiconductor laser diodes along the so-called fast axis. After training using a Gaussian beam ray-equivalent model, the network is capable of indicating the tilt, decenter, and defocus of such lenses from the measured field distribution, so the operator can determine the errors with respect to the actual lens position and optimize the diode assembly procedure. An experimental validation using a typical configuration exploited in multi-emitter diode module assembly and fast axis collimating lenses with different focal lengths and numerical apertures is reported.

Fusion ignition via a magnetically-assisted fast ignition approach

OpenAIRE

Wang, W. -M.; Gibbon, P.; Sheng, Z. -M.; Li, Y. T.; Zhang, J.

2016-01-01

Significant progress has been made towards laser-driven fusion ignition via different schemes, including direct and indirect central ignition, fast ignition, shock ignition, and impact ignition schemes. However, to reach ignition conditions, there are still various technical and physical challenges to be solved for all these schemes. Here, our multi-dimensional integrated simulation shows that the fast-ignition conditions could be achieved when two 2.8 petawatt heating laser pulses counter-pr...

Formation of Offset and Dual Active Galactic Nuclei

Science.gov (United States)

Barrows, Scott; Comerford, Julia M.; Greene, Jenny E.

2018-06-01

Galaxy mergers are effective mechanisms for triggering accretion onto supermassive black holes (SMBHs) and thereby powering active galactic nuclei (AGN). In the merger scenario, when the SMBH from only one galaxy is accreting we observe a spatially offset AGN, and when the SMBHs from both galaxies are accreting we observe a dual AGN. Understanding the merger conditions that lead to the formation of offset AGN versus dual AGN is fundamental to informing models of hierarchical SMBH growth and the physics leading to the accretion of matter onto SMBHs. However, while the role of galaxy mergers for AGN triggering has been well-studied, the efficiency with which these events trigger offset AGN versus dual AGN is currently unclear. One reason for this gap in knowledge can be attributed to the observational difficulties in distinguishing between offset and dual AGN since doing so requires high spatial resolution, especially in the small separation regime where merger-driven AGN triggering is most likely to occur. To overcome this hurdle, we have utilized the spatial resolution of the Chandra X-ray Observatory to develop a unique sample of AGN hosted by late-stage galaxy mergers. Moreover, we have recently acquired Hubble Space Telescope imaging for a subset of these systems to examine the role that their merger morphologies play in SMBH growth and the formation of offset and dual AGN. We find that offset AGN are predominately found in minor mergers, whereas dual AGN are usually hosted by major mergers and galaxies with large morphological asymmetries. Furthermore, in both offset and dual AGN, the rate of SMBH growth increases toward more major mergers and larger morphological asymmetries. These results are in agreement with numerical simulations predicting that merger morphology is a relevant parameter governing SMBH merger-driven growth, and these results are the first to observationally confirm these trends at small pair separations.

Carbon offsets, reversal risk and US climate policy

Directory of Open Access Journals (Sweden)

Chen Yihsu

2009-06-01

Full Text Available Abstract Background One controversial issue in the larger cap-and-trade debate is the proper use and certification of carbon offsets related to changes in land management. Advocates of an expanded offset supply claim that inclusion of such activities would expand the scope of the program and lower overall compliance costs, while opponents claim that it would weaken the environmental integrity of the program by crediting activities that yield either nonexistent or merely temporary carbon sequestration benefits. Our study starts from the premise that offsets are neither perfect mitigation instruments nor useless "hot air." Results We show that offsets provide a useful cost containment function, even when there is some threat of reversal, by injecting additional "when-flexibility" into the system. This allows market participants to shift their reduction requirements to periods of lower cost, thereby facilitating attainment of the least-cost time path without jeopardizing the cumulative environmental integrity of the system. By accounting for market conditions in conjunction with reversal risk, we develop a simple offset valuation methodology, taking into account the two most important factors that typically lead offsets to be overvalued or undervalued. Conclusion The result of this paper is a quantitative "model rule" that could be included in future legislation or used as a basis for active management by a future "carbon fed" or other regulatory authority with jurisdiction over the US carbon market to actively manage allowance prices.

Offset Implementations for Turkey’s International Defense Acquisitions

Science.gov (United States)

2008-12-01

has been a source of confusion in the field of offsets and countertrade (Schmidt, 1989, p. 4) Compensatory trade agreements — or reciprocal trade...complementary policy instruments. Countertrade and offset terms have usually been overall terms to define and classify reciprocal trade agreements...motives and characteristics in nature. Author Grant T. Hammond classifies reciprocal trade as countertrade , offsets and barter — which involve all

Contextual segment-based classification of airborne laser scanner data

NARCIS (Netherlands)

Vosselman, George; Coenen, Maximilian; Rottensteiner, Franz

2017-01-01

Classification of point clouds is needed as a first step in the extraction of various types of geo-information from point clouds. We present a new approach to contextual classification of segmented airborne laser scanning data. Potential advantages of segment-based classification are easily offset

OLT-centralized sampling frequency offset compensation scheme for OFDM-PON.

Science.gov (United States)

Chen, Ming; Zhou, Hui; Zheng, Zhiwei; Deng, Rui; Chen, Qinghui; Peng, Miao; Liu, Cuiwei; He, Jing; Chen, Lin; Tang, Xionggui

2017-08-07

We propose an optical line terminal (OLT)-centralized sampling frequency offset (SFO) compensation scheme for adaptively-modulated OFDM-PON systems. By using the proposed SFO scheme, the phase rotation and inter-symbol interference (ISI) caused by SFOs between OLT and multiple optical network units (ONUs) can be centrally compensated in the OLT, which reduces the complexity of ONUs. Firstly, the optimal fast Fourier transform (FFT) size is identified in the intensity-modulated and direct-detection (IMDD) OFDM system in the presence of SFO. Then, the proposed SFO compensation scheme including phase rotation modulation (PRM) and length-adaptive OFDM frame has been experimentally demonstrated in the downlink transmission of an adaptively modulated optical OFDM with the optimal FFT size. The experimental results show that up to ± 300 ppm SFO can be successfully compensated without introducing any receiver performance penalties.

36 CFR 1011.10 - How will the Presidio Trust use administrative offset (offset of non-tax federal payments) to...

Science.gov (United States)

2010-07-01

... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false How will the Presidio Trust... Trust Debts § 1011.10 How will the Presidio Trust use administrative offset (offset of non-tax federal...) If not already transferred to the FMS under § 1011.9 of this part, the Presidio Trust will refer any...

Estimates of Future Supply of International Greenhouse Gas Offsets: A Critical Review

Energy Technology Data Exchange (ETDEWEB)

Erickson, Peter; Lazarus, Michael (Stockholm Environment Inst. (United States)), e-mail: mlaz@sei-us.org; Kelly, Alexia (World Resources Inst., (United States))

2010-07-01

This report reviews estimates of the projected availability (i.e., supply) of international offsets, evaluates the various methods used and outlines factors that should be incorporated into future analyses of international offset supply and quality. U.S. policymakers have relied on offsets from developing countries as a primary form of cost containment in proposed cap-and-trade legislation. These legislative proposals allow for emitters to use up to 1.5 billion tons CO{sub 2}e of offsets from developing countries to meet their annual compliance obligations. In this paper, we review estimates of the projected availability (i.e., supply) of international offsets, and evaluate the various methods used. We find that: (1) Estimates of supply of international offsets to global markets vary widely, with estimates differing by billions of tons CO{sub 2}e annually in 2020; (2) Despite the variation, existing studies suggest that by 2020 gross international offset supply will likely exceed U.S. demand for international offsets under current Congressional cap-and-trade designs; (3) Competition with governments and entities with emission reduction obligations (e.g. the EU), as well as with policies and measures undertaken by developing countries as part of their own mitigation contributions, could reduce the net offset supply available to U.S. entities; and (4) Several important offset program design and market factors that are central to future offset markets and credit issuance (e.g., sources of offset supply, program stringency and crediting methods, establishment of international governance and market structures) have yet to be systematically considered in offset supply assessments. This paper outlines factors that should be incorporated into future analyses of international offset supply and quality. 7 Such analyses could prove particularly germane as policy makers continue to deliberate on the role of international offsets, including whether and how to recognize credits

41 CFR 105-56.027 - Centralized salary offset computer match.

Science.gov (United States)

2010-07-01

... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false Centralized salary... Services Administration 56-SALARY OFFSET FOR INDEBTEDNESS OF FEDERAL EMPLOYEES TO THE UNITED STATES Centralized Salary Offset (CSO) Procedures-GSA as Paying Agency § 105-56.027 Centralized salary offset...

41 CFR 105-56.017 - Centralized salary offset computer match.

Science.gov (United States)

2010-07-01

... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false Centralized salary... Services Administration 56-SALARY OFFSET FOR INDEBTEDNESS OF FEDERAL EMPLOYEES TO THE UNITED STATES Centralized Salary Offset (CSO) Procedures-GSA as Creditor Agency § 105-56.017 Centralized salary offset...

A stabilized optical frequency comb based on an Er-doped fiber femtosecond laser

Science.gov (United States)

Xia, Chuanqing; Wu, Tengfei; Zhao, Chunbo; Xing, Shuai

2018-03-01

An optical frequency comb based on a 250 MHz home-made Er-doped fiber femtosecond laser is presented in this paper. The Er-doped fiber laser has a ring cavity and operates mode-locked in femtosecond regime with the technique of nonlinear polarization rotation. The pulse duration is 118 fs and the spectral width is 30 nm. A part of the femtosecond laser is amplified in Er-doped fiber amplifier before propagating through a piece of highly nonlinear fiber for expanding the spectrum. The carrier-envelope offset frequency of the comb which has a signal-to-noise ratio more than 35 dB is extracted by means of f-2f beating. It demonstrates that both carrier-envelope offset frequency and repetition frequency keep phase locked to a Rubidium atomic clock simultaneously for 2 hours. The frequency stabilized fiber combs will be increasingly applied in optical metrology, attosecond pulse generation, and absolute distance measurement.

Net present biodiversity value and the design of biodiversity offsets.

Science.gov (United States)

Overton, Jacob McC; Stephens, R T Theo; Ferrier, Simon

2013-02-01

There is an urgent need to develop sound theory and practice for biodiversity offsets to provide a better basis for offset multipliers, to improve accounting for time delays in offset repayments, and to develop a common framework for evaluating in-kind and out-of-kind offsets. Here, we apply concepts and measures from systematic conservation planning and financial accounting to provide a basis for determining equity across type (of biodiversity), space, and time. We introduce net present biodiversity value (NPBV) as a theoretical and practical measure for defining the offset required to achieve no-net-loss. For evaluating equity in type and space we use measures of biodiversity value from systematic conservation planning. Time discount rates are used to address risk of non-repayment, and loss of utility. We illustrate these concepts and measures with two examples of biodiversity impact-offset transactions. Considerable further work is required to understand the characteristics of these approaches.

Measuring coseismic displacements with point-like targets offset tracking

KAUST Repository

Hu, Xie; Wang, Teng; Liao, Mingsheng

2014-01-01

Offset tracking is an important complement to measure large ground displacements in both azimuth and range dimensions where synthetic aperture radar (SAR) interferometry is unfeasible. Subpixel offsets can be obtained by searching for the cross-correlation peak calculated from the match patches uniformly distributed on two SAR images. However, it has its limitations, including redundant computation and incorrect estimations on decorrelated patches. In this letter, we propose a simple strategy that performs offset tracking on detected point-like targets (PT). We first detect image patches within bright PT by using a sinc-like template from a single SAR image and then perform offset tracking on them to obtain the pixel shifts. Compared with the standard method, the application on the 2010 M 7.2 El Mayor-Cucapah earthquake shows that the proposed PT offset tracking can significantly increase the cross-correlation and thus result in both efficiency and reliability improvements. © 2013 IEEE.

Ultrafast photoconductive detector-laser-diode transmitter

International Nuclear Information System (INIS)

Wang, C.L.; Davies, T.J.; Nelson, M.A.; Thomas, M.C.; Zagarino, P.A.; Davis, B.A.

1987-01-01

The authors report the results of an experiment in which they used an ultrafast, photoconductive, radiation detector to drive a fast laser-diode transmitter. When they irradiated the neutron-damaged Cr-doped Ga/As detector with 17-MeV electron beams, the temporal response of was measured to be less than 30 ps. The pulses from this detector modulated a fast GaAlAs laser diode to transmit the laser output through 30- and 1100-m optical fibers. Preliminary results indicate that 50- and 80-ps time resolutions, respectively, are obtainable with these fibers. They are now working to integrate the photoconductive detector and the laser diode transmitter into a single chip

12 CFR 1704.29 - Coordinating salary offset with other agencies.

Science.gov (United States)

2010-01-01

... 12 Banks and Banking 7 2010-01-01 2010-01-01 false Coordinating salary offset with other agencies... HOUSING AND URBAN DEVELOPMENT OFHEO ORGANIZATION AND FUNCTIONS DEBT COLLECTION Salary Offset § 1704.29 Coordinating salary offset with other agencies. (a) Responsibility of OFHEO as the creditor agency. (1) OFHEO...

Fast Prototyping of Sensorized Cell Culture Chips and Microfluidic Systems with Ultrashort Laser Pulses

Directory of Open Access Journals (Sweden)

Sebastian M. Bonk

2015-03-01

Full Text Available We developed a confined microfluidic cell culture system with a bottom plate made of a microscopic slide with planar platinum sensors for the measurement of acidification, oxygen consumption, and cell adhesion. The slides were commercial slides with indium tin oxide (ITO plating or were prepared from platinum sputtering (100 nm onto a 10-nm titanium adhesion layer. Direct processing of the sensor structures (approximately three minutes per chip by an ultrashort pulse laser facilitated the production of the prototypes. pH-sensitive areas were produced by the sputtering of 60-nm Si3N4 through a simple mask made from a circuit board material. The system body and polydimethylsiloxane (PDMS molding forms for the microfluidic structures were manufactured by micromilling using a printed circuit board (PCB milling machine for circuit boards. The microfluidic structure was finally imprinted in PDMS. Our approach avoided the use of photolithographic techniques and enabled fast and cost-efficient prototyping of the systems. Alternatively, the direct production of metallic, ceramic or polymeric molding tools was tested. The use of ultrashort pulse lasers improved the precision of the structures and avoided any contact of the final structures with toxic chemicals and possible adverse effects for the cell culture in lab-on-a-chip systems.

5 CFR 1639.28 - Coordinating salary offset with other agencies.

Science.gov (United States)

2010-01-01

... 5 Administrative Personnel 3 2010-01-01 2010-01-01 false Coordinating salary offset with other... CLAIMS COLLECTION Salary Offset § 1639.28 Coordinating salary offset with other agencies. (a... employee is in the process of separating and has not received a final salary check or other final payment(s...

Attention capture by contour onsets and offsets: no special role for onsets.

Science.gov (United States)

Watson, D G; Humphreys, G W

1995-07-01

In five experiments, we investigated the power of targets defined by the onset or offset of one of an object's parts (contour onsets and offsets) either to guide or to capture visual attention. In Experiment 1, search for a single contour onset target was compared with search for a single contour offset target against a static background of distractors; no difference was found between the efficiency with which each could be detected. In Experiment 2, onsets and offsets were compared for automatic attention capture, when both occurred simultaneously. Unlike in previous studies, the effects of overall luminance change, new-object creation, and number of onset and offset items were controlled. It was found that contour onset and offset items captured attention equally well. However, display size effects on both target types were also apparent. Such effects may have been due to competition for selection between multiple onset and offset stimuli. In Experiments 3 and 4, single onset and offset stimuli were presented simultaneously and pitted directly against one another among a background of static distractors. In Experiment 3, we examined "guided search," for a target that was formed either from an onset or from an offset among static items. In Experiment 4, the onsets and offsets were uncorrelated with the target location. Similar results occurred in both experiments: target onsets and offsets were detected more efficiently than static stimuli which needed serial search; there remained effects of display size on performance; but there was still no advantage for onsets. In Experiment 5, we examined automatic attention capture by single onset and offset stimuli presented individually among static distractors. Again, there was no advantage for onset over offset targets and a display size effect was also present. These results suggest that, both in isolation and in competition, onsets that do not form new objects neither guide nor gain automatic attention more efficiently

Possible correlations between gamma-ray burst and its host galaxy offset

Science.gov (United States)

Wang, Fei-Fei; Zou, Yuan-Chuan; Liu, Yu; Liao, Bin; Moharana, Reetanjali

2018-06-01

We collected the information of 304 gamma-ray bursts (GRBs) from the literature, and analyzed the correlations among the host galaxy offsets (the distance from the site of the GRB to the center of its host galaxy), T90,i (the duration T90 in rest-frame), TR45,i (the duration TR45 in rest-frame), Eγ,iso (the isotropic equivalent energy), Lγ,iso (=Eγ,iso /T90,i, the isotropic equivalent luminosity) and Lpk (peak luminosity). We found that T90,i, TR45,i, Eγ,iso, Lpk have negative correlation with offset, which is consistent with origin of short GRBs (SGRBs) and long GRBs (LGRBs). On separate analysis, we found similar results for log ⁡Eγ,iso - log ⁡ (offset) and log ⁡Lpk - log ⁡ (offset) relations in case of SGRBs only, while no obvious relation for LGRBs. There is no correlations between offset and Lγ,iso. We also put the special GRB 170817A and GRB 060218A on the plots. The two GRBs both have low luminosity and small offset. In the log ⁡ (offset) - log ⁡T90,i plot, we found GRB 170817A locates in between the two regions of SGRBs and LGRBs and it is the outlier in the offset -Eγ,iso, offset -Lγ,iso and offset -Lpk plots. Together with GRB 060218A being an outlier in all plots, it indicates the speciality of GRBs 170817A and 060218A, and might imply more subgroups of the GRB samples.

Alternative method for determining the constant offset in lidar signal

Science.gov (United States)

Vladimir A. Kovalev; Cyle Wold; Alexander Petkov; Wei Min Hao

2009-01-01

We present an alternative method for determining the total offset in lidar signal created by a daytime background-illumination component and electrical or digital offset. Unlike existing techniques, here the signal square-range-correction procedure is initially performed using the total signal recorded by lidar, without subtraction of the offset component. While...

Proceedings of national laser symposium (NLS-2000)

International Nuclear Information System (INIS)

Mallik, Amitav; Srivastava, K.N.; Pal, Suranjan

2000-01-01

This proceedings comprise of a series of invited talks on selected topics in lasers and wide range of contributed papers. The main topics are laser physics and research, laser devices and technology, laser materials and spectroscopy, quantum optics, non-linear optics ultra-fast phenomenon, laser produced plasma, high power lasers, laser instrumentation, medical applications and industrial applications of lasers and fiber optics. The papers relevant to INIS Database are indexed separately

Offsets and conservation of the species of the EU habitats and birds directives.

Science.gov (United States)

Regnery, Baptiste; Couvet, Denis; Kerbiriou, Christian

2013-12-01

Biodiversity offsets are intended to achieve no net loss of biodiversity due to economic and human development. A variety of biodiversity components are addressed by offset policies. It is required that loss of protected species due to development be offset under the EU Habitats and Birds Directives in Europe. We call this type of offset a species-equality offset because the offset pertains to the same species affected by the development project. Whether species equality can be achieved by offset design is unknown. We addressed this gap by reviewing derogation files (i.e., specific files that describe mitigation measures to ensure no net loss under the EU Habitats and Birds Directives) from 85 development projects in France (2009-2010). We collected information on type of effect (reversible vs. irreversible) and characteristics of affected and offset sites (i.e., types of species, total area). We analyzed how the type of effect and the affected-site characteristics influenced the occurrence of offset measures. The proportion of species targeted by offset measures (i.e., offset species) increased with the irreversibility of the effect of development and the conservation status of the species affected by development (i.e., affected species). Not all effects on endangered species (International Union for Conservation of Nature Red List) were offset; on average, 82% of affected species would be offset. Twenty-six percent of species of least concern were offset species. Thirty-five percent of development projects considered all affected species in their offset measures. Species richness was much lower in offset sites than in developed sites even after offset proposals. For developed areas where species richness was relatively high before development, species richness at offset sites was 5-10 times lower. The species-equality principle appears to have been applied only partially in offset policies, as in the EU directives. We suggest the application of this principle

1 Hz fast-heating fusion driver HAMA pumped by a 10 J green diode-pumped solid-state laser

International Nuclear Information System (INIS)

Mori, Y.; Komeda, O.; Nakayama, S.; Ishii, K.; Hanayama, R.; Fujita, K.; Okihara, S.; Sekine, T.; Satoh, N.; Kurita, T.; Kawashima, T.; Kan, H.; Nakamura, N.; Kondo, T.; Fujine, M.; Azuma, H.; Hioki, T.; Kakeno, M.; Motohiro, T.; Nishimura, Y.

2013-01-01

A Ti : sapphire laser HAMA pumped by a diode-pumped solid-state laser (DPSSL) is developed to enable a high-repetitive inertial confinement fusion (ICF) experiment to be conducted. To demonstrate a counter-irradiation fast-heating fusion scheme, a 3.8 J, 0.4 ns amplified chirped pulse is divided into four beams: two counter-irradiate a target with intensities of 6 × 10 13 W cm −2 , and the remaining two are pulse-compressed to 110 fs for heating the imploded target with intensities of 2 × 10 17 W cm −2 . HAMA contributed to the first demonstration by showing that a 10 J class DPSSL is adaptable to ICF experiments and succeeded in DD neutron generation in the repetition mode. Based on HAMA, we can design and develop an integrated repetitive ICF experiment machine by including target injection and tracking. (paper)

Diagnosing high density, fast-evolving plasmas using x-ray lasers

International Nuclear Information System (INIS)

Cauble, R.; Da Silva, L.B.; Barbee, T.W. Jr.

1994-09-01

As x-ray laser (XRL) research has matured, it has become possible to reliably utilize XRLs for applications in the laboratory. Laser coherence, high brightness and short pulse duration all make the XRL a unique tool for the diagnosis of laboratory plasmas. The high brightness of XRLs makes them well-suited for imaging and for interferometry when used in conjunction with multilayer mirrors and beamsplitters. We have utilized a soft x-ray laser in such an imaging system to examine laser-produced plasmas using radiography, moire deflectometry, and interferometry. Radiography experiments yield 100-200 ps snapshots of laser driven foils at a resolution of 1-2 μm. Moire deflectometry with an XRL has been used to probe plasmas at higher density than by optical means. Interferograms, which allow direct measurement of electron density in laser plasmas, have been obtained with this system

Measuring coalignment of retroreflectors with large lateral incoming-outgoing beam offset

Energy Technology Data Exchange (ETDEWEB)

Schütze, Daniel, E-mail: Daniel.Schuetze@aei.mpg.de; Sheard, Benjamin S.; Heinzel, Gerhard; Danzmann, Karsten [Max Planck Institute for Gravitational Physics (Albert Einstein Institute) and Institute for Gravitational Physics, Leibniz Universität Hannover, Callinstr. 38, 30167 Hanover (Germany); Farrant, David [Commonwealth Scientific and Industrial Research Organisation, Bradfield Road, Lindfield, NSW 2070 (Australia); Shaddock, Daniel A. [Centre for Gravitational Physics, Australian National University, Acton, ACT 0200 (Australia)

2014-03-15

A method based on phase-shifting Fizeau interferometry is presented with which retroreflectors with large incoming-outgoing beam separations can be tested. The method relies on a flat Reference Bar that is used to align two auxiliary mirrors parallel to each other to extend the aperture of the interferometer. The method is applied to measure the beam coalignment of a prototype Triple Mirror Assembly of the GRACE Follow-On Laser Ranging Interferometer, a future satellite-to-satellite tracking device for Earth gravimetry. The Triple Mirror Assembly features a lateral beam offset of incoming and outgoing beam of 600 mm, whereas the acceptance angle for the incoming beam is only about ±2 mrad. With the developed method, the beam coalignment of the prototype Triple Mirror Assembly was measured to be 9 μrad with a repeatability of below 1 μrad.

Measuring coalignment of retroreflectors with large lateral incoming-outgoing beam offset

International Nuclear Information System (INIS)

Schütze, Daniel; Sheard, Benjamin S.; Heinzel, Gerhard; Danzmann, Karsten; Farrant, David; Shaddock, Daniel A.

2014-01-01

A method based on phase-shifting Fizeau interferometry is presented with which retroreflectors with large incoming-outgoing beam separations can be tested. The method relies on a flat Reference Bar that is used to align two auxiliary mirrors parallel to each other to extend the aperture of the interferometer. The method is applied to measure the beam coalignment of a prototype Triple Mirror Assembly of the GRACE Follow-On Laser Ranging Interferometer, a future satellite-to-satellite tracking device for Earth gravimetry. The Triple Mirror Assembly features a lateral beam offset of incoming and outgoing beam of 600 mm, whereas the acceptance angle for the incoming beam is only about ±2 mrad. With the developed method, the beam coalignment of the prototype Triple Mirror Assembly was measured to be 9 μrad with a repeatability of below 1 μrad

Common-image gathers in the offset domain from reverse-time migration

KAUST Repository

Zhan, Ge; Zhang, Minyu

2014-01-01

Kirchhoff migration is flexible to output common-image gathers (CIGs) in the offset domain by imaging data with different offsets separately. These CIGs supply important information for velocity model updates and amplitude-variation-with-offset (AVO

45 CFR 1179.8 - Procedures for salary offset.

Science.gov (United States)

2010-10-01

... 45 Public Welfare 3 2010-10-01 2010-10-01 false Procedures for salary offset. 1179.8 Section 1179... AND THE HUMANITIES NATIONAL ENDOWMENT FOR THE HUMANITIES SALARY OFFSET § 1179.8 Procedures for salary... to final salary payment or leave in accordance with 31 U.S.C. 3716. ...

6 CFR 13.44 - Right to administrative offset.

Science.gov (United States)

2010-01-01

... 6 Domestic Security 1 2010-01-01 2010-01-01 false Right to administrative offset. 13.44 Section 13.44 Domestic Security DEPARTMENT OF HOMELAND SECURITY, OFFICE OF THE SECRETARY PROGRAM FRAUD CIVIL REMEDIES § 13.44 Right to administrative offset. The amount of any penalty or assessment that has become...

22 CFR 213.21 - Employee salary offset-general.

Science.gov (United States)

2010-04-01

... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Employee salary offset-general. 213.21 Section... § 213.21 Employee salary offset—general. (a) Purpose. This section establishes USAID's policies and... account of an employee. (b) Scope. The provisions of this section apply to collection by salary offset...

Impacts of GNSS position offsets on global frame stability

Science.gov (United States)

Griffiths, Jake; Ray, Jim

2014-05-01

Positional offsets appear in Global Navigation Satellite System (GNSS) time series for a variety of reasons. Antenna or radome changes are the most common cause for these discontinuities. Many others are from earthquakes, receiver changes, and different anthropogenic modifications at or near the stations. Some jumps appear for unknown or undocumented reasons. The accurate determination of station velocities, and therefore geophysical parameters and terrestrial reference frames, requires that positional offsets be correctly found and compensated. Williams (2003) found that undetected offsets introduce a random walk error component in individual station time series. The topic of detecting positional offsets has received considerable attention in recent years (e.g., Detection of Offsets in GPS Experiment; DOGEx), and most research groups using GNSS have adopted a combination of manual and automated methods for finding them. The removal of a positional offset is usually handled by estimating the average station position on both sides of the discontinuity, assuming a constant, continuous velocity. This is sufficient in the absence of time-correlated errors. However, GNSS time series contain systematic and power-law errors (white to random walk noise). In this paper, we aim to evaluate the impact to both individual station results and the overall stability of the global reference frame from adding increasing numbers of positional discontinuities. We use the International GNSS Service (IGS) weekly SINEX files, and iteratively insert positional offset parameters at the midpoint of each data segment. Each iteration includes a restacking of the modified SINEX files using the CATREF software from Institut National de l'Information Géographique et Forestière (IGN) to estimate: regularized station positions, secular velocities, Earth orientation parameters, Helmert frame alignment parameters, and the empirical shifts across all positional discontinuities. A comparison of the

Advanced Concept Exploration for Fast Ignition Science Program, Final Report

Energy Technology Data Exchange (ETDEWEB)

Stephens, Richard Burnite [General Atomics; McLean, Harry M. [Lawrence Livermore National Laboratory; Theobald, Wolfgang [Laboratory for Laser Energetics; Akli, Kramer U. [The Ohio State University; Beg, Farhat N. [University of California, San Diego; Sentoku, Yasuhiko [University of Nevada, Reno; Schumacher, Douglass W. [The Ohio State University; Wei, Mingsheng [General Atomics

2013-09-04

The Fast Ignition (FI) Concept for Inertial Confinement Fusion (ICF) has the potential to provide a significant advance in the technical attractiveness of Inertial Fusion Energy reactors. FI differs from conventional “central hot spot” (CHS) target ignition by decoupling compression from heating: using a laser (or heavy ion beam or Z pinch) drive pulse (10’s of nanoseconds) to create a dense fuel and a second, much shorter (~10 picoseconds) high intensity pulse to ignite a small volume within the dense fuel. The physics of fast ignition process was the focus of our Advanced Concept Exploration (ACE) program. Ignition depends critically on two major issues involving Relativistic High Energy Density (RHED) physics: The laser-induced creation of fast electrons and their propagation in high-density plasmas. Our program has developed new experimental platforms, diagnostic packages, computer modeling analyses, and taken advantage of the increasing energy available at laser facilities to advance understanding of the fundamental physics underlying these issues. Our program had three thrust areas: • Understand the production and characteristics of fast electrons resulting from FI relevant laser-plasma interactions and their dependence on laser prepulse and laser pulse length. • Investigate the subsequent fast electron transport in solid and through hot (FI-relevant) plasmas. • Conduct and understand integrated core-heating experiments by comparison to simulations. Over the whole period of this project (three years for this contract), we have greatly advanced our fundamental understanding of the underlying properties in all three areas: • Comprehensive studies on fast electron source characteristics have shown that they are controlled by the laser intensity distribution and the topology and plasma density gradient. Laser pre-pulse induced pre-plasma in front of a solid surface results in increased stand-off distances from the electron origin to the high density

"3D_Fault_Offsets," a Matlab Code to Automatically Measure Lateral and Vertical Fault Offsets in Topographic Data: Application to San Andreas, Owens Valley, and Hope Faults

Science.gov (United States)

Stewart, N.; Gaudemer, Y.; Manighetti, I.; Serreau, L.; Vincendeau, A.; Dominguez, S.; Mattéo, L.; Malavieille, J.

2018-01-01

Measuring fault offsets preserved at the ground surface is of primary importance to recover earthquake and long-term slip distributions and understand fault mechanics. The recent explosion of high-resolution topographic data, such as Lidar and photogrammetric digital elevation models, offers an unprecedented opportunity to measure dense collections of fault offsets. We have developed a new Matlab code, 3D_Fault_Offsets, to automate these measurements. In topographic data, 3D_Fault_Offsets mathematically identifies and represents nine of the most prominent geometric characteristics of common sublinear markers along faults (especially strike slip) in 3-D, such as the streambed (minimum elevation), top, free face and base of channel banks or scarps (minimum Laplacian, maximum gradient, and maximum Laplacian), and ridges (maximum elevation). By calculating best fit lines through the nine point clouds on either side of the fault, the code computes the lateral and vertical offsets between the piercing points of these lines onto the fault plane, providing nine lateral and nine vertical offset measures per marker. Through a Monte Carlo approach, the code calculates the total uncertainty on each offset. It then provides tools to statistically analyze the dense collection of measures and to reconstruct the prefaulted marker geometry in the horizontal and vertical planes. We applied 3D_Fault_Offsets to remeasure previously published offsets across 88 markers on the San Andreas, Owens Valley, and Hope faults. We obtained 5,454 lateral and vertical offset measures. These automatic measures compare well to prior ones, field and remote, while their rich record provides new insights on the preservation of fault displacements in the morphology.

ND:GLASS LASER DESIGN FOR LASER ICF FISSION ENERGY (LIFE)

International Nuclear Information System (INIS)

Caird, J.A.; Agrawal, V.; Bayramian, A.; Beach, R.; Britten, J.; Chen, D.; Cross, R.; Ebbers, C.; Erlandson, A.; Feit, M.; Freitas, B.; Ghosh, C.; Haefner, C.; Homoelle, D.; Ladran, T.; Latkowski, J.; Molander, W.; Murray, J.; Rubenchik, S.; Schaffers, K.; Siders, C.W.; Stappaerts, E.; Sutton, S.; Telford, S.; Trenholme, J.; Barty, C.J.

2008-01-01

We have developed preliminary conceptual laser system designs for the Laser ICF (Inertial Confinement Fusion) Fission Energy (LIFE) application. Our approach leverages experience in high-energy Nd:glass laser technology developed for the National Ignition Facility (NIF), along with high-energy-class diode-pumped solid-state laser (HEC-DPSSL) technology developed for the DOE's High Average Power Laser (HAPL) Program and embodied in LLNL's Mercury laser system. We present laser system designs suitable for both indirect-drive, hot spot ignition and indirect-drive, fast ignition targets. Main amplifiers for both systems use laser-diode-pumped Nd:glass slabs oriented at Brewster's angle, as in NIF, but the slabs are much thinner to allow for cooling by high-velocity helium gas as in the Mercury laser system. We also describe a plan to mass-produce pump-diode lasers to bring diode costs down to the order of $0.01 per Watt of peak output power, as needed to make the LIFE application economically attractive

22 CFR 213.22 - Salary offset when USAID is the creditor agency.

Science.gov (United States)

2010-04-01

... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Salary offset when USAID is the creditor agency... Administrative Offset § 213.22 Salary offset when USAID is the creditor agency. (a) Due process requirements... through salary offset, USAID will first provide the employee with the opportunity to pay in full the...

7 CFR 3.81 - Procedures for salary offset: when deductions may begin.

Science.gov (United States)

2010-01-01

... 7 Agriculture 1 2010-01-01 2010-01-01 false Procedures for salary offset: when deductions may... Salary Offset § 3.81 Procedures for salary offset: when deductions may begin. (a) Deductions to liquidate... Offset Salary to collect from the employee's current pay. (b) If the employee filed a petition for a...

40 CFR 13.22 - Salary offset when EPA is the creditor agency.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Salary offset when EPA is the creditor... COLLECTION STANDARDS Administrative Offset § 13.22 Salary offset when EPA is the creditor agency. (a... through salary offset, EPA will first provide the employee with the opportunity to pay in full the amount...

1978 annual report on laser fusion research

International Nuclear Information System (INIS)

Johnson, R.R.

1978-01-01

Progress during this period is reported for each of the following topics: (1) spherical shell fuel containers, (2) polymer research, (3) cryogenic technology, (4) fabrication technology, (5) implosion physics, (6) fast ion measurements of laser-produced spherical plasmas, (7) absorbed energy measurements, (8) diagnostics, (9) fast ion energy loss in dense plasmas, (10) electron transport, (11) ionization equation of state, (12) profile modification by pondermotive forces, (13) pondermotive potential effects on Ohm's law, (14) effect of flux-limited thermal transport on critical surface jump conditions, (15) spherical rarefaction shocks, (16) explosively heated Gaussian objects, (17) bandwidth broadening, (18) frequency doubling experiments, (19) advanced laser candidates, (20) glass laser operation, and (21) 2TW laser upgrade

45 CFR 33.8 - Voluntary repayment agreement in lieu of salary offset.

Science.gov (United States)

2010-10-01

... 45 Public Welfare 1 2010-10-01 2010-10-01 false Voluntary repayment agreement in lieu of salary... SALARY OFFSET § 33.8 Voluntary repayment agreement in lieu of salary offset. (a)(1) In response to the... notice of intent to offset. An employee who wishes to repay the debt without salary offset shall also...

Supression of laser breakdown by pulsed nonequilibrium ns discharge

Science.gov (United States)

Starikovskiy, A. Y.; Semenov, I. E.; Shneider, M. N.

2016-10-01

The avalanche ionization induced by infrared laser pulses was investigated in a pre-ionized argon gas. Pre-ionization was created by a high-voltage pulsed nanosecond discharge developed in the form of a fast ionization wave. Then, behind the front of ionization wave additional avalanche ionization was initiated by the focused Nd-YAG laser pulse. It was shown that the gas pre-ionization inhibits the laser spark generation. It was demonstrated that the suppression of laser spark development in the case of strong gas pre-ionization is because of fast electron energy transfer from the laser beam focal region. The main mechanism of this energy transfer is free electrons diffusion.

Interfacial microstructure and mechanical property of Ti6Al4V/A6061 dissimilar joint by direct laser brazing without filler metal and groove

International Nuclear Information System (INIS)

Song, Zhihua; Nakata, Kazuhiro; Wu, Aiping; Liao, Jinsun

2013-01-01

Laser brazing of Ti6Al4V and A6061-T6 alloys with 2 mm thickness was conducted by focusing laser beam on aluminum alloy side, and the effect of laser offset distance on microstructure and mechanical properties of the dissimilar butt joint was investigated. Laser offset has a great influence on the thickness of interfacial intermetallic compound (IMC) layer and the mechanical property of joint. The thickness of interfacial IMC layer is less than 500 nm, and the average tensile strength of the joint reaches 64% of aluminum base material strength, when suitable welding conditions are used. The interfacial IMC is TiAl 3 . The formation of interfacial IMC layer and its effect on mechanical property of the joint are discussed in the present study.

Flexible Laser Metal Cutting

DEFF Research Database (Denmark)

Villumsen, Sigurd; Jørgensen, Steffen Nordahl; Kristiansen, Morten

2014-01-01

This paper describes a new flexible and fast approach to laser cutting called ROBOCUT. Combined with CAD/CAM technology, laser cutting of metal provides the flexibility to perform one-of-a-kind cutting and hereby realises mass production of customised products. Today’s laser cutting techniques...... possess, despite their wide use in industry, limitations regarding speed and geometry. Research trends point towards remote laser cutting techniques which can improve speed and geometrical freedom and hereby the competitiveness of laser cutting compared to fixed-tool-based cutting technology...... such as punching. This paper presents the concepts and preliminary test results of the ROBOCUT laser cutting technology, a technology which potentially can revolutionise laser cutting....

36 CFR 1201.32 - What are NARA's procedures for salary offset?

Science.gov (United States)

2010-07-01

... for salary offset? 1201.32 Section 1201.32 Parks, Forests, and Public Property NATIONAL ARCHIVES AND RECORDS ADMINISTRATION GENERAL RULES COLLECTION OF CLAIMS Salary Offset § 1201.32 What are NARA's procedures for salary offset? (a) NARA will coordinate salary deductions under this subpart as appropriate...

BPM Offset Determination by Sinusoidal Quadrupole K-modulation

CERN Document Server

Baer, T; Wenninger, J

2011-01-01

To ensure an adequate orbit steering that maximizes the machine aperture, a good knowledge of the BPM measurement offsets is crucial. During this MD, a sinusoidal k-modulation of individually powered quadrupoles was performed to determine the offsets of the nearby BPMs. An accuracy of 10µm for the determination of the absolute beam position is reached.

Conceptual design study for a laser fusion hybrid

International Nuclear Information System (INIS)

Maniscalco, J.A.

1976-01-01

Lawrence Livermore Laboratory and Bechtel Corporation have been involved in a joint effort to conceptually design a laser fusion hybrid reactor. The design which has evolved is a depleted-uranium fueled fast-fission blanket which produces fissile plutonium and electricity. A major objective of the design study was to evaluate the feasibility of producing fissile fuel with laser fusion. This feasibility evaluation was carried out by analyzing the integrated engineering performance of the complete conceptual design and by identifying the required laser/pellet performance. The performance of the laser fusion hybrid has also been compared to a typical fast breeder reactor. The results show that the laser fusion hybrid produces enough fissile material to fuel more than six light water reactors (LWRs) of equivalent thermal power while operating in a regime which requires an order of magnitude less laser and pellet performance than pure laser fusion. In comparison to a fast breeder reactor the hybrid produces 10 times more fissile fuel. An economic analysis of the design shows that the cost of electricity in a combined hybrid-LWR scenario increases by only 20 to 40 percent when the capital cost of the hybrid ranges from 2 to 3 times more than an LWR

Conceptual design study for a laser fusion hybrid

International Nuclear Information System (INIS)

Maniscalco, J.A.

1976-09-01

Lawrence Livermore Laboratory and Bechtel Corporation have been involved in a joint effort to conceptually design a laser fusion hybrid reactor. The design which has evolved is a depleted-uranium fueled fast-fission blanket which produces fissile plutonium and electricity. A major objective of the design study was to evaluate the feasibility of producing fissile fuel with laser fusion. This feasibility evaluation was carried out by analyzing the integrated engineering performance of the complete conceptual design and by identifying the required laser/pellet performance. The performance of the laser fusion hybrid has also been compared to a typical fast breeder reactor. The results show that the laser fusion hybrid produces enough fissile material to fuel more than six light water reactors (LWR's) of equivalent thermal power while operating in a regime which requires an order of magnitude less laser and pellet performance than pure laser fusion. In comparison to a fast breeder reactor the hybrid produces 10 times more fissile fuel. An economic analysis of the design shows that the cost of electricity in a combined hybrid-LWR scenario is insensitive to the capital cost of the hybrid, increasing by only 20 to 40 percent when the capital cost of the hybrid ranges from 2 to 3 times more than an LWR

Linear induction accelerator requirements for ion fast ignition

International Nuclear Information System (INIS)

Logan, G.

1998-01-01

Fast ignition (fast heating of DT cores afief compression) reduces driver energy (by 10 X or more) by reducing the implosion velocity and energy for a given fuel compression ratio. For any type of driver that can deliver the ignition energy fast enough, fast ignition increases the target gain compared to targets using fast implosions for central ignition, as long as the energy to heat the core after compression is comparable to or less than the slow compression energy, and as long as the coupling efficiency of the fast ignitor beam to heat the core is comparable to the overall efficiency of compressing the core (in terms of beam energy-to-DT-efficiency). Ion driven fast ignition, compared to laser-driven fast ignition, has the advantage of direct (dE/dx) deposition of beam energy to the DT, eliminating inefficiencies for conversion into hot electrons, and direct ion heating also has a more favorable deposition profile with the Bragg-peak near the end of an ion range chosen to be deep inside a compressed DT core. While Petawatt laser experiments at LLNL have demonstrated adequate light-to-hot-electron conversion efficiency, it is not yet known if light and hot electrons can channel deeply enough to heat a small portion of a IOOOxLD compressed DT core to ignition. On the other hand, lasers with chirped-pulse amplification giving thousand-fold pulse compressions have been demonstrated to produce the short pulses, small focal spots and Petawatt peak powers approaching those required for fast ignition, whereas ion accelerators that can produce sufficient beam quality for similar compression ratios and focal spot sizes of ion bunches have not yet been demonstrated, where an imposed coherent velocity tilt plays the analogous role for beam compression as does frequency chirp with lasers. Accordingly, it is the driver technology, not the target coupling physics, that poses the main challenge to ion-driven fast ignition. As the mainline HIF program is concentrating on

Offsetting the impacts of mining to achieve no net loss of native vegetation.

Science.gov (United States)

Sonter, L J; Barrett, D J; Soares-Filho, B S

2014-08-01

Offsets are a novel conservation tool, yet using them to achieve no net loss of biodiversity is challenging. This is especially true when using conservation offsets (i.e., protected areas) because achieving no net loss requires avoiding equivalent loss. Our objective was to determine if offsetting the impacts of mining achieves no net loss of native vegetation in Brazil's largest iron mining region. We used a land-use change model to simulate deforestation by mining to 2020; developed a model to allocate conservation offsets to the landscape under 3 scenarios (baseline, no new offsets; current practice, like-for-like [by vegetation type] conservation offsetting near the impact site; and threat scenario, like-for-like conservation offsetting of highly threatened vegetation); and simulated nonmining deforestation to 2020 for each scenario to quantify avoided deforestation achieved with offsets. Mines cleared 3570 ha of native vegetation by 2020. Under a 1:4 offset ratio, mining companies would be required to conserve >14,200 ha of native vegetation, doubling the current extent of protected areas in the region. Allocating offsets under current practice avoided deforestation equivalent to 3% of that caused by mining, whereas allocating under the threat scenario avoided 9%. Current practice failed to achieve no net loss because offsets did not conserve threatened vegetation. Explicit allocation of offsets to threatened vegetation also failed because the most threatened vegetation was widely dispersed across the landscape, making conservation logistically difficult. To achieve no net loss with conservation offsets requires information on regional deforestation trajectories and the distribution of threatened vegetation. However, in some regions achieving no net loss through conservation may be impossible. In these cases, other offsetting activities, such as revegetation, will be required. © 2014 Society for Conservation Biology.

Offsets : An innovative approach to reducing greenhouse gases

International Nuclear Information System (INIS)

Steward, B.

1998-01-01

One of the most innovative ways to address climate change is the use of offsets, which refers to actions taken outside of a company's operations, domestically and internationally, to reduce greenhouse gas emissions. This paper is devoted to a discussion of Suncor Energy's action plan for greenhouse gases which include offsets, and to an explanation of the reasons why offsets are fundamental to successful greenhouse gas management. Suncor Energy Inc., has developed a plan with seven elements to meet their target of stabilizing their greenhouse gas emissions at 1990 levels by year 2000. The seven elements include: (1) energy efficiency and process improvements at their oil sands facility, (2) the development of alternative and renewable sources of energy, such as ethanol blended gasolines and the use of wind turbines to generate electricity, (3) promoting environmental and economic research to develop more advanced oil and gas technology to reduce greenhouse gas emissions, (4) implementing a constructive public policy input in support of sustainable development, (5) educating employees, customers and communities on global climate change, (6) measuring and reporting the company's environmental progress, and (7) pursuing domestic and international offset opportunities such as transfer of technology to developing countries, cogeneration of energy using natural gas, energy efficiency, renewable energy sources, emission reduction purchases and forest conservation. Of these proposed measures, offsets are the critical element which could spell the difference between success and failure in managing greenhouse gas emissions and the difference between economic hardship and economic opportunity

24 CFR 17.137 - Procedures for salary offset: imposition of interest.

Science.gov (United States)

2010-04-01

... 24 Housing and Urban Development 1 2010-04-01 2010-04-01 false Procedures for salary offset: imposition of interest. 17.137 Section 17.137 Housing and Urban Development Office of the Secretary... the Government Salary Offset Provisions § 17.137 Procedures for salary offset: imposition of interest...

24 CFR 17.136 - Procedures for salary offset: methods of collection.

Science.gov (United States)

2010-04-01

... 24 Housing and Urban Development 1 2010-04-01 2010-04-01 false Procedures for salary offset: methods of collection. 17.136 Section 17.136 Housing and Urban Development Office of the Secretary... the Government Salary Offset Provisions § 17.136 Procedures for salary offset: methods of collection...

24 CFR 17.135 - Procedures for salary offset: types of collection.

Science.gov (United States)

2010-04-01

... 24 Housing and Urban Development 1 2010-04-01 2010-04-01 false Procedures for salary offset: types of collection. 17.135 Section 17.135 Housing and Urban Development Office of the Secretary... the Government Salary Offset Provisions § 17.135 Procedures for salary offset: types of collection. A...

12 CFR 608.841 - Requesting current paying agency to offset salary.

Science.gov (United States)

2010-01-01

... salary. 608.841 Section 608.841 Banks and Banking FARM CREDIT ADMINISTRATION ADMINISTRATIVE PROVISIONS COLLECTION OF CLAIMS OWED THE UNITED STATES Offset Against Salary § 608.841 Requesting current paying agency to offset salary. (a) To request a paying agency to impose a salary offset against amounts owed to...

Laser excited novel near-infrared photoluminescence bands in fast neutron-irradiated MgO·nAl2O3

International Nuclear Information System (INIS)

Rahman, Abu Zayed Mohammad Saliqur; Haseeb, A.S.M.A.; Xu, Qiu; Evslin, Jarah; Cinausero, Marco

2016-01-01

New near-infrared photoluminescence bands were observed in neutron-irradiated spinel single crystal upon excitation by a 532 nm laser. The surface morphology of the unirradiated and fast neutron-irradiated samples was investigated using atomic force microscopy and scanning probe microscopy. Fast neutron-irradiated samples show a strong emission peak at 1685 nm along with weak bands at 1065 and 2365 nm. The temperature dependence of the photoluminescence intensity was also measured. At lower temperatures, the dominant peak at 1685 nm shifts toward lower energy whereas the other peaks remain fixed. Activation energies of luminescence quenching were estimated to be 5.7 and 54.6 meV for the lower and higher temperature regions respectively. - Highlights: • AFM and SPM were conducted to understand surface morphology of the unirrad and neutron-irradiated spinel. • Novel photoluminescence band at 1685 nm along with weak bands at 1065 and 2365 was observed. • Activation energy for luminescence quenching was estimated from Arrhenius equation.

Contribution to the replacement of cobalt-free hardfacing coating by laser cladding in fast neutron reactors

International Nuclear Information System (INIS)

De-Tran, Van

2014-01-01

This thesis contributes to the replacement of the coating of Stellite 6 which is used in friction areas for the primary circuit of the fast neutron reactor. It contains three parts: 1) A literature review for selecting the materials and the deposition process 2) A parametric study to get healthy deposits (good adhesion with the substrate, little porosity, no cracks, low dilution) 3) A study wear behavior of deposits obtained, at high temperature (200 C) under an atmosphere inert gas, to determine the wear resistance of materials selected without the influence of an eventual oxidation layer. From the literature review, it appears the following choices implemented in our study: * the method laser cladding with advantages such as: - Good adhesion (metallurgical) - High cooling speed - Low dilution rate - Wide parametric range * two nickel-based alloys: Colmonoy-52 and Tribaloy-700. These alloys have good dry wear behavior and could be deposited by the laser. In the manufacturing part of the healthy deposit, firstly, we characterized the metal powder. Then, a parametric study was performed to look for a good parametric range that makes us getting a healthy deposit of Stellite 6 (reference) of Colmonoy-52 and Tribaloy-700. In this case, relationships among three main process parameters laser cladding (laser beam power, surface scanning speed, rate of powder) with the microstructure and chemical composition of the deposit are studied. In study the wear behavior, a pin-on-disc type of tribological was used and tests were carried out in argon at room temperature and 200 C. We investigated the wear mechanism of the best deposition of Stellite 6, Colmonoy-52 and Tribaloy-700. The wear resistance of these materials were thoroughly compared. (author) [fr

7 CFR 3.83 - Procedures for salary offset: methods of collection.

Science.gov (United States)

2010-01-01

... 7 Agriculture 1 2010-01-01 2010-01-01 false Procedures for salary offset: methods of collection. 3.83 Section 3.83 Agriculture Office of the Secretary of Agriculture DEBT MANAGEMENT Federal Salary Offset § 3.83 Procedures for salary offset: methods of collection. (a) General. A debt will be collected...

Femtosecond laser pulses for fast 3-D surface profilometry of microelectronic step-structures.

Science.gov (United States)

Joo, Woo-Deok; Kim, Seungman; Park, Jiyong; Lee, Keunwoo; Lee, Joohyung; Kim, Seungchul; Kim, Young-Jin; Kim, Seung-Woo

2013-07-01

Fast, precise 3-D measurement of discontinuous step-structures fabricated on microelectronic products is essential for quality assurance of semiconductor chips, flat panel displays, and photovoltaic cells. Optical surface profilers of low-coherence interferometry have long been used for the purpose, but the vertical scanning range and speed are limited by the micro-actuators available today. Besides, the lateral field-of-view extendable for a single measurement is restricted by the low spatial coherence of broadband light sources. Here, we cope with the limitations of the conventional low-coherence interferometer by exploiting unique characteristics of femtosecond laser pulses, i.e., low temporal but high spatial coherence. By scanning the pulse repetition rate with direct reference to the Rb atomic clock, step heights of ~69.6 μm are determined with a repeatability of 10.3 nm. The spatial coherence of femtosecond pulses provides a large field-of-view with superior visibility, allowing for a high volume measurement rate of ~24,000 mm3/s.

Constraining The Abundance Of Massive Black Hole Binaries By Spectroscopic Monitoring Of Quasars With Offset Broad Emission Lines

Science.gov (United States)

Liu, Xin; Shen, Y.

2012-05-01

A fraction of quasars have long been known to show significant bulk velocity offsets (of a few hundred to thousands of km/s) in the broad permitted emission lines with respect to host galaxy systemic redshift. Various scenarios may explain these features such as massive black hole binaries or broad line region gas kinematics. As previously demonstrated by the dedicated work of Eracleous and colleagues, long-term spectroscopic monitoring provides a promising test to discriminate between alternative scenarios. Here, we present a sample of 300 shifted-line quasars homogeneously selected from the SDSS DR7. For 60 of them, we have conducted second-epoch optical spectra using MMT/BCS, ARC 3.5m/DIS, and/or FLWO 1.5m/FAST. These new observations, combined with the existing SDSS spectra, enable us to constrain the velocity drifts of these shifted broad lines with time baselines of a few years up to a decade. Previous work has been focusing on objects with extreme velocity offsets: > 1000 km/s. Our work extends to the parameter space of smaller velocity offsets, where larger velocity drifts would be expected in the binary scenario. Our results may be used to identify strong candidates for and to constrain the abundance of massive black hole binaries, which are expected in the hierarchical universe, but have so far been illusive.

12 CFR 1408.41 - Requesting current paying agency to offset salary.

Science.gov (United States)

2010-01-01

... salary. 1408.41 Section 1408.41 Banks and Banking FARM CREDIT SYSTEM INSURANCE CORPORATION COLLECTION OF CLAIMS OWED THE UNITED STATES Offset Against Salary § 1408.41 Requesting current paying agency to offset salary. (a) To request a paying agency to impose a salary offset against amounts owed to the debtor, the...

7 CFR 3.82 - Procedures for salary offset: types of collection.

Science.gov (United States)

2010-01-01

... 7 Agriculture 1 2010-01-01 2010-01-01 false Procedures for salary offset: types of collection. 3.82 Section 3.82 Agriculture Office of the Secretary of Agriculture DEBT MANAGEMENT Federal Salary Offset § 3.82 Procedures for salary offset: types of collection. A debt will be collected in a lump-sum...

7 CFR 400.141 - Internal Revenue Service (IRS) Tax Refund Offset.

Science.gov (United States)

2010-01-01

... 7 Agriculture 6 2010-01-01 2010-01-01 false Internal Revenue Service (IRS) Tax Refund Offset. 400...-Regulations for the 1986 and Succeeding Crop Years § 400.141 Internal Revenue Service (IRS) Tax Refund Offset... debt owing to any Federal agency by offset against a taxpayer's Federal income tax refund. This section...

THE NATURE OF ACTIVE GALACTIC NUCLEI WITH VELOCITY OFFSET EMISSION LINES

Energy Technology Data Exchange (ETDEWEB)

Müller-Sánchez, F.; Comerford, J. [Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO 80309 (United States); Stern, D. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Harrison, F. A. [California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States)

2016-10-10

We obtained Keck/OSIRIS near-IR adaptive optics-assisted integral-field spectroscopy to probe the morphology and kinematics of the ionized gas in four velocity-offset active galactic nuclei (AGNs) from the Sloan Digital Sky Survey. These objects possess optical emission lines that are offset in velocity from systemic as measured from stellar absorption features. At a resolution of ∼0.″18, OSIRIS allows us to distinguish which velocity offset emission lines are produced by the motion of an AGN in a dual supermassive black hole system, and which are produced by outflows or other kinematic structures. In three galaxies, J1018+2941, J1055+1520, and J1346+5228, the spectral offset of the emission lines is caused by AGN-driven outflows. In the remaining galaxy, J1117+6140, a counterrotating nuclear disk is observed that contains the peak of Pa α emission 0.″2 from the center of the galaxy. The most plausible explanation for the origin of this spatially and kinematically offset peak is that it is a region of enhanced Pa α emission located at the intersection zone between the nuclear disk and the bar of the galaxy. In all four objects, the peak of ionized gas emission is not spatially coincident with the center of the galaxy as traced by the peak of the near-IR continuum emission. The peaks of ionized gas emission are spatially offset from the galaxy centers by 0.″1–0.″4 (0.1–0.7 kpc). We find that the velocity offset originates at the location of this peak of emission, and the value of the offset can be directly measured in the velocity maps. The emission-line ratios of these four velocity-offset AGNs can be reproduced only with a mixture of shocks and AGN photoionization. Shocks provide a natural explanation for the origin of the spatially and spectrally offset peaks of ionized gas emission in these galaxies.

38 CFR 3.658 - Offsets; dependency and indemnity compensation.

Science.gov (United States)

2010-07-01

... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false Offsets; dependency and... AFFAIRS ADJUDICATION Pension, Compensation, and Dependency and Indemnity Compensation Adjustments and Resumptions § 3.658 Offsets; dependency and indemnity compensation. (a) When an award of dependency and...

Optical design and analysis of carbon dioxide laser fusion systems using interferometry and fast Fourier transform techniques

International Nuclear Information System (INIS)

Viswanathan, V.K.

1979-01-01

The optical design and analysis of the LASL carbon dioxide laser fusion systems required the use of techniques that are quite different from the currently used method in conventional optical design problems. The necessity for this is explored and the method that has been successfully used at Los Alamos to understand these systems is discussed with examples. This method involves characterization of the various optical components in their mounts by a Zernike polynomial set and using fast Fourier transform techniques to propagate the beam, taking diffraction and other nonlinear effects that occur in these types of systems into account. The various programs used for analysis are briefly discussed

Black-body anomaly: analysis of temperature offsets

International Nuclear Information System (INIS)

Szopa, M.; Hofmann, R.; Schwarz, M.; Giacosa, F.

2008-01-01

Based on the postulate that photon propagation is governed by a dynamically broken SU(2) gauge symmetry (scale ∝10 -4 eV) we make predictions for temperature offsets due to a low-temperature (a few times the present CMB temperature) spectral anomaly at low frequencies. Temperature offsets are extracted from least-square fits of the anomalous black-body spectra to their conventional counterparts. We discuss statistical errors, compare our results with those obtained from calibration data of the FIRAS instrument, and point out that our predicted offsets are screened by experimental errors given the frequency range used by FIRAS to perform their spectral fits. We also make contact with the WMAP observation by blueshifting their frequency bands. Although our results hint towards a strong dynamical component in the CMB dipole and an explanation of low-l suppression, it is important in view of its particle-physics implications that the above postulate be verified/falsified by an independent low-temperature black-body precision experiment. (orig.)

Offset-electrode profile acquisition strategy for electrical resistivity tomography

Science.gov (United States)

Robbins, Austin R.; Plattner, Alain

2018-04-01

We present an electrode layout strategy that allows electrical resistivity profiles to image the third dimension close to the profile plane. This "offset-electrode profile" approach involves laterally displacing electrodes away from the profile line in an alternating fashion and then inverting the resulting data using three-dimensional electrical resistivity tomography software. In our synthetic and field surveys, the offset-electrode method succeeds in revealing three-dimensional structures in the vicinity of the profile plane, which we could not achieve using three-dimensional inversions of linear profiles. We confirm and explain the limits of linear electrode profiles through a discussion of the three-dimensional sensitivity patterns: For a homogeneous starting model together with a linear electrode layout, all sensitivities remain symmetric with respect to the profile plane through each inversion step. This limitation can be overcome with offset-electrode layouts by breaking the symmetry pattern among the sensitivities. Thanks to freely available powerful three-dimensional resistivity tomography software and cheap modern computing power, the requirement for full three-dimensional calculations does not create a significant burden and renders the offset-electrode approach a cost-effective method. By offsetting the electrodes in an alternating pattern, as opposed to laying the profile out in a U-shape, we minimize shortening the profile length.

ND:GLASS LASER DESIGN FOR LASER ICF FISSION ENERGY (LIFE)

Energy Technology Data Exchange (ETDEWEB)

Caird, J A; Agrawal, V; Bayramian, A; Beach, R; Britten, J; Chen, D; Cross, R; Ebbers, C; Erlandson, A; Feit, M; Freitas, B; Ghosh, C; Haefner, C; Homoelle, D; Ladran, T; Latkowski, J; Molander, W; Murray, J; Rubenchik, S; Schaffers, K; Siders, C W; Stappaerts, E; Sutton, S; Telford, S; Trenholme, J; Barty, C J

2008-10-28

We have developed preliminary conceptual laser system designs for the Laser ICF (Inertial Confinement Fusion) Fission Energy (LIFE) application. Our approach leverages experience in high-energy Nd:glass laser technology developed for the National Ignition Facility (NIF), along with high-energy-class diode-pumped solid-state laser (HEC-DPSSL) technology developed for the DOE's High Average Power Laser (HAPL) Program and embodied in LLNL's Mercury laser system. We present laser system designs suitable for both indirect-drive, hot spot ignition and indirect-drive, fast ignition targets. Main amplifiers for both systems use laser-diode-pumped Nd:glass slabs oriented at Brewster's angle, as in NIF, but the slabs are much thinner to allow for cooling by high-velocity helium gas as in the Mercury laser system. We also describe a plan to mass-produce pump-diode lasers to bring diode costs down to the order of $0.01 per Watt of peak output power, as needed to make the LIFE application economically attractive.

Progress of laser nuclear fusion research

International Nuclear Information System (INIS)

Shiraga, Hiroyuki

2017-01-01

This paper describes the principle and features of nuclear fusion using laser, as well as its basic concepts such as high-temperature / high-density implosion system and fast ignition of fuel. At present, researches aiming at nuclear fusion ignition have been developing. As the current state of researches, this paper reviews the situations of FIREX (Fast Ignition Realization Experiment) project of Japan focusing on direct irradiation implosion and fast ignition system, as well as NIF (National Ignition Facility) project of the U.S. aiming at ignition combustion based on indirect irradiation implosion and central ignition system. In collaboration with the National Institute for Fusion Science, Osaka University started FIREX-1 project in 2003. It built a heating laser LFEX of 10 kJ/1 to 10ps, and started an implosion/heating integration experiment in 2009. Currently, it is developing experiment to achieve heating to 5 keV. At NIF, the self-heating of central sparks via energy of α particles generated in the nuclear fusion reaction has been realized. This paper also overviews R and D issues surrounding the lasers for reactors for use in laser nuclear fusion power generators. (A.O.)

A Computer Simulation of the System-Wide Effects of Parallel-Offset Route Maneuvers

Science.gov (United States)

Lauderdale, Todd A.; Santiago, Confesor; Pankok, Carl

2010-01-01

Most aircraft managed by air-traffic controllers in the National Airspace System are capable of flying parallel-offset routes. This paper presents the results of two related studies on the effects of increased use of offset routes as a conflict resolution maneuver. The first study analyzes offset routes in the context of all standard resolution types which air-traffic controllers currently use. This study shows that by utilizing parallel-offset route maneuvers, significant system-wide savings in delay due to conflict resolution of up to 30% are possible. It also shows that most offset resolutions replace horizontal-vectoring resolutions. The second study builds on the results of the first and directly compares offset resolutions and standard horizontal-vectoring maneuvers to determine that in-trail conflicts are often more efficiently resolved by offset maneuvers.

Offsets in International Weapons Acquisitions: The Turkish Experience

Science.gov (United States)

2002-03-01

Countertrade : In addition to the types of offsets defined above, various types of commercial countertrade arrangements may be required. A contract may...Offsets, Industrial Participation and Countertrade ,” A Compendium of Developments in the Military and Civil Sectors 1995-2000, Presidential Commission...www.ssm.gov.tr/english/projekriterlering.htm ) Internet accessed 14 January 2002b. Schaffer, Lindsey. Winning The Countertrade War, (New York, John Wiley

Ultra fast imaging of a laser wake field accelerator

Energy Technology Data Exchange (ETDEWEB)

Saevert, Alexander; Schnell, Michael; Nicolai, Maria; Reuter, Maria; Schwab, Matthew B.; Moeller, Max [Friedrich-Schiller-Universitaet, Jena (Germany); Mangles, Stuart P.D.; Cole, Jason M.; Poder, Kristjan; Najmudin, Zulfikar [The John Adams Institute Imperial College, London (United Kingdom); Jaeckel, Oliver; Paulus, Gerhard G.; Spielmann, Christian; Kaluza, Malte C. [Friedrich-Schiller-Universitaet, Jena (Germany); Helmholtz Institut Jena, Jena (Germany)

2014-07-01

Ultra intense laser pulses are known to excite plasma waves with a relativistic phase velocity. By harnessing these waves it is possible to generate quasi-monoenergetic, ultra-short electron pulses with kinetic energies from 0.1 to 2 GeV by guiding the laser pulse over several Rayleigh lengths. To further improve the stability of these particle pulses and ultimately to be able to tailor the energy spectrum toward their suitability for various applications, the physics underlying the different acceleration scenarios need to be understood as completely as possible. To be able to resolve the acceleration process diagnostics well-suited for this plasma environment need to be designed and realized. By using sub-10 fs probe pulses we were able to freeze the transient accelerating structure in the plasma. We will present the first results of an experiment which was carried out with the 30 TW JETi Laser and a few cycle probe pulse at the Institute of Optics and Quantum Electronics Jena. The resulting snapshots show unprecedented details from the laser plasma interaction and allow a direct comparison to computer simulations.

Synchronisation of a femtosecond laser and a Q-switched laser to within 50 ps

International Nuclear Information System (INIS)

Katin, E V; Lozhkarev, V V; Palashov, O V; Khazanov, E A

2003-01-01

A Nd:YLF laser emitting 2-ns pulses synchronised with a femtosecond Cr:forsterite laser is built. The pulse duration and synchronisation are ensured by two Pockels cells, in which voltage pulses are synchronised with the femtosecond laser by fast emitter-coupled logic elements. One of the Pockels cells ensures Q-switching, while the other cuts a short pulse from a 15-ns Q-switched pulse. The experimental results show that the two-step scheme proposed for synchronisation of a Q-switched laser and a passively mode-locked laser provides quite simple and reliable synchronisation of these lasers with a jitter of a few tens of picoseconds. (control of laser radiation parameters)

Tuning SISO offset-free Model Predictive Control based on ARX models

DEFF Research Database (Denmark)

Huusom, Jakob Kjøbsted; Poulsen, Niels Kjølstad; Jørgensen, Sten Bay

2012-01-01

, the proposed controller is simple to tune as it has only one free tuning parameter. These two features are advantageous in predictive process control as they simplify industrial commissioning of MPC. Disturbance rejection and offset-free control is important in industrial process control. To achieve offset......In this paper, we present a tuning methodology for a simple offset-free SISO Model Predictive Controller (MPC) based on autoregressive models with exogenous inputs (ARX models). ARX models simplify system identification as they can be identified from data using convex optimization. Furthermore......-free control in face of unknown disturbances or model-plant mismatch, integrators must be introduced in either the estimator or the regulator. Traditionally, offset-free control is achieved using Brownian disturbance models in the estimator. In this paper we achieve offset-free control by extending the noise...

Laser speckle contrast imaging of skin blood perfusion responses induced by laser coagulation

Energy Technology Data Exchange (ETDEWEB)

Ogami, M; Kulkarni, R; Wang, H; Reif, R; Wang, R K [University of Washington, Department of Bioengineering, Seattle, Washington 98195 (United States)

2014-08-31

We report application of laser speckle contrast imaging (LSCI), i.e., a fast imaging technique utilising backscattered light to distinguish such moving objects as red blood cells from such stationary objects as surrounding tissue, to localise skin injury. This imaging technique provides detailed information about the acute perfusion response after a blood vessel is occluded. In this study, a mouse ear model is used and pulsed laser coagulation serves as the method of occlusion. We have found that the downstream blood vessels lacked blood flow due to occlusion at the target site immediately after injury. Relative flow changes in nearby collaterals and anastomotic vessels have been approximated based on differences in intensity in the nearby collaterals and anastomoses. We have also estimated the density of the affected downstream vessels. Laser speckle contrast imaging is shown to be used for highresolution and fast-speed imaging for the skin microvasculature. It also allows direct visualisation of the blood perfusion response to injury, which may provide novel insights to the field of cutaneous wound healing. (laser biophotonics)

41 CFR 105-56.008 - Pre-offset paper hearing.

Science.gov (United States)

2010-07-01

... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false Pre-offset paper hearing. 105-56.008 Section 105-56.008 Public Contracts and Property Management Federal Property Management... General Services Administration Employees § 105-56.008 Pre-offset paper hearing. If a hearing is to be...

The solid state detector technology for picosecond laser ranging

Science.gov (United States)

Prochazka, Ivan

1993-01-01

We developed an all solid state laser ranging detector technology, which makes the goal of millimeter accuracy achievable. Our design and construction philosophy is to combine the techniques of single photon ranging, ultrashort laser pulses, and fast fixed threshold discrimination while avoiding any analog signal processing within the laser ranging chain. The all solid state laser ranging detector package consists of the START detector and the STOP solid state photon counting module. Both the detectors are working in an optically triggered avalanche switching regime. The optical signal is triggering an avalanche current buildup which results in the generation of a uniform, fast risetime output pulse.

Femtosecond laser-matter interaction theory, experiments and applications

CERN Document Server

Gamaly, Eugene G

2011-01-01

Basics of Ultra-Short Laser-Solid InteractionsSubtle Atomic Motion Preceding a Phase Transition: Birth, Life and Death of PhononsUltra-Fast Disordering by fs-Lasers: Superheating Prior to Entropy CatastropheAblation of SolidsUltra-Short Laser-Matter Interaction Confined Inside a Bulk of Transparent SolidApplications of Ultra-Short Laser-Matter InteractionsConclusion Remarks.

Antiproton fast ignition for inertial confinement fusion

International Nuclear Information System (INIS)

Perkins, L.J.

1999-01-01

With 180 MJ/microg, antiprotons offer the highest stored energy per unit mass of any known entity. The use of antiprotons to promote fast ignition in an inertial confinement fusion (ICF) capsule and produce high target gains with only modest compression of the main fuel is investigated. Unlike standard fast ignition where the ignition energy is supplied by energetic, short pulse laser, the energy here is supplied through the ionization energy deposited when antiprotons annihilate at the center of a compressed fuel capsule. This can be considered in-situ fast ignition as it obviates the need for the external injection of the ignition energy. In the first of two candidate schemes, the antiproton package is delivered by a low-energy ion beam. In the second, autocatalytic scheme, the antiprotons are preemplaced at the center of the capsule prior to compression. In both schemes, the author estimates that ∼10 12 antiprotons are required to initiate fast ignition in a typical ICF capsule and show that incorporation of a thin, heavy metal shell is desirable to enhance energy deposition within the ignitor zone. In addition to eliminating the need for a second, energetic fast laser and vulnerable final optics, this scheme would achieve central ignition without reliance on laser channeling through halo plasma or Hohlraum debris. However, in addition to the practical difficulties of storage and manipulation of antiprotons at low energy, the other large uncertainty for the practicality of such a speculative scheme is the ultimate efficiency of antiproton production in an external, optimized facility. Estimates suggest that the electrical wall plug energy per pulse required for the separate production of the antiprotons is of the same order as that required for the conventional slow compression driver

22 CFR 213.23 - Salary offset when USAID is not the creditor agency.

Science.gov (United States)

2010-04-01

... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Salary offset when USAID is not the creditor... Administrative Offset § 213.23 Salary offset when USAID is not the creditor agency. (a) USAID will use salary... installment, if a date other than the next established pay period. (b) Requests for salary offset must be sent...

On determining fluxgate magnetometer spin axis offsets from mirror mode observations

Science.gov (United States)

Plaschke, Ferdinand; Narita, Yasuhito

2016-09-01

In-flight calibration of fluxgate magnetometers that are mounted on spacecraft involves finding their outputs in vanishing ambient fields, the so-called magnetometer offsets. If the spacecraft is spin-stabilized, then the spin plane components of these offsets can be relatively easily determined, as they modify the spin tone content in the de-spun magnetic field data. The spin axis offset, however, is more difficult to determine. Therefore, usually Alfvénic fluctuations in the solar wind are used. We propose a novel method to determine the spin axis offset: the mirror mode method. The method is based on the assumption that mirror mode fluctuations are nearly compressible such that the maximum variance direction is aligned to the mean magnetic field. Mirror mode fluctuations are typically found in the Earth's magnetosheath region. We introduce the method and provide a first estimate of its accuracy based on magnetosheath observations by the THEMIS-C spacecraft. We find that 20 h of magnetosheath measurements may already be sufficient to obtain high-accuracy spin axis offsets with uncertainties on the order of a few tenths of a nanotesla, if offset stability can be assumed.

On determining fluxgate magnetometer spin axis offsets from mirror mode observations

Directory of Open Access Journals (Sweden)

F. Plaschke

2016-09-01

Full Text Available In-flight calibration of fluxgate magnetometers that are mounted on spacecraft involves finding their outputs in vanishing ambient fields, the so-called magnetometer offsets. If the spacecraft is spin-stabilized, then the spin plane components of these offsets can be relatively easily determined, as they modify the spin tone content in the de-spun magnetic field data. The spin axis offset, however, is more difficult to determine. Therefore, usually Alfvénic fluctuations in the solar wind are used. We propose a novel method to determine the spin axis offset: the mirror mode method. The method is based on the assumption that mirror mode fluctuations are nearly compressible such that the maximum variance direction is aligned to the mean magnetic field. Mirror mode fluctuations are typically found in the Earth's magnetosheath region. We introduce the method and provide a first estimate of its accuracy based on magnetosheath observations by the THEMIS-C spacecraft. We find that 20 h of magnetosheath measurements may already be sufficient to obtain high-accuracy spin axis offsets with uncertainties on the order of a few tenths of a nanotesla, if offset stability can be assumed.

Fast Growth of GaN Epilayers via Laser-Assisted Metal-Organic Chemical Vapor Deposition for Ultraviolet Photodetector Applications.

Science.gov (United States)

Rabiee Golgir, Hossein; Li, Da Wei; Keramatnejad, Kamran; Zou, Qi Ming; Xiao, Jun; Wang, Fei; Jiang, Lan; Silvain, Jean-François; Lu, Yong Feng

2017-06-28

In this study, we successfully developed a carbon dioxide (CO 2 )-laser-assisted metal-organic chemical vapor deposition (LMOCVD) approach to fast synthesis of high-quality gallium nitride (GaN) epilayers on Al 2 O 3 [sapphire(0001)] substrates. By employing a two-step growth procedure, high crystallinity and smooth GaN epilayers with a fast growth rate of 25.8 μm/h were obtained. The high crystallinity was confirmed by a combination of techniques, including X-ray diffraction, Raman spectroscopy, transmission electron microscopy, and atomic force microscopy. By optimizing growth parameters, the ∼4.3-μm-thick GaN films grown at 990 °C for 10 min showed a smooth surface with a root-mean-square surface roughness of ∼1.9 nm and excellent thickness uniformity with sharp GaN/substrate interfaces. The full-width at half-maximum values of the GaN(0002) X-ray rocking curve of 313 arcsec and the GaN(101̅2) X-ray rocking curve of 390 arcsec further confirmed the high crystallinity of the GaN epilayers. We also fabricated ultraviolet (UV) photodetectors based on the as-grown GaN layers, which exhibited a high responsivity of 0.108 A W -1 at 367 nm and a fast response time of ∼125 ns, demonstrating its high optical quality with potential in optoelectronic applications. Our strategy thus provides a simple and cost-effective means toward fast and high-quality GaN heteroepitaxy growth suitable for fabricating high-performance GaN-based UV detectors.

Notes on Laser Acceleration

International Nuclear Information System (INIS)

Tajima, T.

2008-01-01

This note intends to motivate our effort toward the advent of new methods of particle acceleration, utilizing the fast rising laser technology. By illustrating the underlying principles in an intuitive manner and thus less jargon-clad fashion, we seek a direction in which we shall be able to properly control and harness the promise of laser acceleration. First we review the idea behind the laser wakefield. We then go on to examine ion acceleration by laser. We examine the sheath acceleration in particular and look for the future direction that allows orderly acceleration of ions in high energies

Buying a laser - tips and pearls.

Science.gov (United States)

Aurangabadkar, Sanjeev J; Mysore, Venkataram; Ahmed, E Suhail

2014-04-01

Lasers and aesthetic procedures have transformed dermatology practice. They have aided in the treatment of hitherto untreatable conditions and allowed better financial remuneration to the physician. The availability of a variety of laser devices of different makes, specifications and pricing has lead to confusion and dilemma in the mind of the buying physician. There are presently no guidelines available for buying a laser. Since purchase of a laser involves large investments, careful consideration to laser specifications, training, costing, warranty, availability of spares, and reliability of service are important prerequisites. This article describes various factors that are needed to be considered and also attempts to lay down criteria to be assessed while buying a laser system that will be useful to physicians before investing in a laser machine. Meticulous planning of the type of machine, specifications, financial aspects, maintenance and warranties is important.It is wise to sign a contract or agreement between the buyer and seller before purchase of a laser which covers key aspects of installation, after sales service and maintenance of the machine.Adequate training is essential; understanding laser physics and laser-tissue interaction goes a long way in getting the best out of the machine.The credibility of the dealer and company should be ascertained in order to be assured of after-sales service.Buying used machines, sharing of equipment to offset high initial investments is a good option but even more care is required to ensure proper functioning and maintenance.

Performance and Vibration Analyses of Lift-Offset Helicopters

Directory of Open Access Journals (Sweden)

Jeong-In Go

2017-01-01

Full Text Available A validation study on the performance and vibration analyses of the XH-59A compound helicopter is conducted to establish techniques for the comprehensive analysis of lift-offset compound helicopters. This study considers the XH-59A lift-offset compound helicopter using a rigid coaxial rotor system as a verification model. CAMRAD II (Comprehensive Analytical Method of Rotorcraft Aerodynamics and Dynamics II, a comprehensive analysis code, is used as a tool for the performance, vibration, and loads analyses. A general free wake model, which is a more sophisticated wake model than other wake models, is used to obtain good results for the comprehensive analysis. Performance analyses of the XH-59A helicopter with and without auxiliary propulsion are conducted in various flight conditions. In addition, vibration analyses of the XH-59A compound helicopter configuration are conducted in the forward flight condition. The present comprehensive analysis results are in good agreement with the flight test and previous analyses. Therefore, techniques for the comprehensive analysis of lift-offset compound helicopters are appropriately established. Furthermore, the rotor lifts are calculated for the XH-59A lift-offset compound helicopter in the forward flight condition to investigate the airloads characteristics of the ABC™ (Advancing Blade Concept rotor.

5 CFR 179.209 - Voluntary repayment agreement as alternative to salary offset.

Science.gov (United States)

2010-01-01

... alternative to salary offset. 179.209 Section 179.209 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS CLAIMS COLLECTION STANDARDS Salary Offset § 179.209 Voluntary repayment agreement as alternative to salary offset. (a)(1) In response to a notice of intent, an employee may propose...

The beam based alignment technique for the measurements of beam position monitors offsets and beam offsets from quadrupoles in the Pohang Light Source

International Nuclear Information System (INIS)

Kim, K.H.; Huang, J.Y.; Ko, I.S.

1999-01-01

The beam based alignment (BBA) technique is applied to the 2-GeV storage ring of the Pohang Light Source to measure the offsets of beam position monitors. This measurement is particularly necessary for beam position monitors (BPMs) plugged into a long (∼10 m) aluminum chamber, since the mechanical deformation of the vacuum chamber is experienced after repeated heating for the outgassing process, and the BPM positions are changed accordingly. A part of the excitation current of each quadrupole magnet is shunted through an electronic shunt circuit. Then, the closed orbit receives a perturbation due to the current reduction. Using two quadrupole magnets, we can measure the offset of each BPM. Also, the BBA technique is applied to measure the beam offsets from the center of quadrupole magnets, and gives information to the survey team about which quadrupole magnets should be aligned mostly. In this process, we introduce the merit function to reduce various errors such as BPM characteristic changes and the lattice imperfection. By minimizing the merit function, we can get the beam offset as the maximized expectation value. This paper presents the BBA technique used and experimental results taken from the 2-GeV Pohang Light Source (PLS) storage ring. When the BPM offset is measured, it is observed that a 3% of the shunt current is suitable. (author)

Laser-assisted chemical vapor deposition setup for fast synthesis of graphene patterns

Science.gov (United States)

Zhang, Chentao; Zhang, Jianhuan; Lin, Kun; Huang, Yuanqing

2017-05-01

An automatic setup based on the laser-assisted chemical vapor deposition method has been developed for the rapid synthesis of graphene patterns. The key components of this setup include a laser beam control and focusing unit, a laser spot monitoring unit, and a vacuum and flow control unit. A laser beam with precision control of laser power is focused on the surface of a nickel foil substrate by the laser beam control and focusing unit for localized heating. A rapid heating and cooling process at the localized region is induced by the relative movement between the focalized laser spot and the nickel foil substrate, which causes the decomposing of gaseous hydrocarbon and the out-diffusing of excess carbon atoms to form graphene patterns on the laser scanning path. All the fabrication parameters that affect the quality and number of graphene layers, such as laser power, laser spot size, laser scanning speed, pressure of vacuum chamber, and flow rates of gases, can be precisely controlled and monitored during the preparation of graphene patterns. A simulation of temperature distribution was carried out via the finite element method, providing a scientific guidance for the regulation of temperature distribution during experiments. A multi-layer graphene ribbon with few defects was synthesized to verify its performance of the rapid growth of high-quality graphene patterns. Furthermore, this setup has potential applications in other laser-based graphene synthesis and processing.

Laser Cutting of Thin Nickel Bellows

Science.gov (United States)

Butler, C. L.

1986-01-01

Laser cutting technique produces narrow, precise, fast, and repeatable cuts in thin nickel-allow bellows material. Laser cutting operation uses intense focused beam to melt material and assisting gas to force melted material through part thickness, creating void. When part rotated or moved longitudinally, melting and material removal continuous and creates narrow, fast, precise, and repeatable cut. Technique used to produce cuts of specified depths less than material thickness. Avoids distortion, dents, and nicks produced in delicate materials during lathe trimming operations, which require high cutting-tool pressure and holding-fixture forces.

38 CFR 1.991 - Procedures for salary offset: when deductions may begin.

Science.gov (United States)

2010-07-01

... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false Procedures for salary offset: when deductions may begin. 1.991 Section 1.991 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS GENERAL PROVISIONS Salary Offset Provisions § 1.991 Procedures for salary offset...

Non-destructive evaluation of fiber-reinforced composites with a fast 2D fiber-optic laser-ultrasound scanner

Science.gov (United States)

Pelivanov, Ivan; Buma, Takashi; Xia, Jinjun; Wei, Chen-Wei; Shtokolov, Alex; O'Donnell, Matthew

2015-03-01

Laser ultrasonic (LU) inspection represents an attractive, non-contact method to evaluate composite materials. Current non-contact systems, however, have relatively low sensitivity compared to contact piezoelectric detection. They are also difficult to adjust, very expensive, and strongly influenced by environmental noise. Here, we demonstrate that most of these drawbacks can be eliminated by combining a new generation of compact, inexpensive fiber lasers with new developments in fiber telecommunication optics and an optimally designed balanced probe scheme. In particular, a new type of a balanced fiber-optic Sagnac interferometer is presented as part of an all-optical LU pump-probe system for high speed non-destructive testing and evaluation (NDT&E) of aircraft composites. The performance of the LU system is demonstrated on a composite sample typically used in the aircraft industry. Wide-band ultrasound probe signals are generated directly at the sample surface with a pulsed diode-pumped laser delivering nanosecond laser pulses at a 1 kHz repetition rate with a pulse energy of 2 mJ. A balanced fiber-optic Sagnac interferometer is employed to detect pressure signals in a 1-10 MHz frequency range at the same point (an 8 μm focal spot) on the composite surface. A fast (up to 100 mm/s) 2D translation system is employed to move the sample during scanning and produce a complete B-scan consisting of one thousand A-scans in less than a second. The sensitivity of this system, in terms of the noise equivalent pressure, is found to be only 10 dB above the Nyquist thermal noise limit. To our knowledge, this is the best reported sensitivity for a non-contact ultrasonic detector of this dimension.

An x-ray technique for precision laser beam synchronization

International Nuclear Information System (INIS)

Landen, O.L.; Lerche, R.A.; Hay, R.G.; Hammel, B.A.; Kalantar, D.; Cable, M.D.

1994-01-01

A new x-ray technique for recording the relative arrival times of multiple laser beams at a common target with better than ± 10 ps accuracy has been implemented at the Nova laser facility. 100 ps, 3ω Nova beam are focused to separate locations on a gold ribbon target viewed from the side. The measurement consists of using well characterized re-entrant x-ray streak cameras for 1-dimensional streaked imaging of the > 3 keV x-rays emanating from these isolated laser plasmas. After making the necessary correction for the differential laser, x-ray and electron transit times involved, timing offsets as low as ± 7 ps are resolved, and on subsequent shots, corrected for, verified and independently checked. This level of synchronization proved critical in meeting the power balance requirements for indirectly-driven pulse-shaped Nova implosions

Localisation of beam offset jitter sources at ATF2

CERN Document Server

Pfingstner, J; Patecki, M; Schulte, D; Tomás, R

2014-01-01

For the commissioning and operation of modern particle accelerators, automated error detection and diagnostics methods are becoming increasingly important. In this paper, we present two such methods, which are capable of localising sources of beam offset jitter with a combination of correlation studies and so called degree of freedom plots. The methods were applied to the ATF2 beam line at KEK, where one of the major goals is the reduction of the beam offset jitter. Results of this localisation are shown in this paper. A big advantage of the presented method is its high robustness especially to varying optics parameters. Therefore, we believe that the developed beam offset jitter localisation methods can be easily applied to other accelerators.

PEP Laser Surveying System

International Nuclear Information System (INIS)

Lauritzen, T.; Sah, R.C.

1979-03-01

A Laser Surveying System has been developed to survey the beam elements of the PEP storage ring. This system provides automatic data acquisition and analysis in order to increase survey speed and to minimize operator error. Two special instruments, the Automatic Readout Micrometer and the Small Automatic Micrometer, have been built for measuring the locations of fiducial points on beam elements with respect to the light beam from a laser. These instruments automatically encode offset distances and read them into the memory of an on-line computer. Distances along the beam line are automatically encoded with a third instrument, the Automatic Readout Tape Unit. When measurements of several beam elements have been taken, the on-line computer analyzes the measured data, compared them with desired parameters, and calculates the required adjustments to beam element support stands

Tracing Supermassive Black Hole Growth with Offset and Dual AGN

Science.gov (United States)

Comerford, Julia

The growth of supermassive black holes is tied to the evolution of their host galaxies, but we are still missing a fundamental understanding of how and when supermassive black holes build up their mass. Black hole mass growth can be traced when the black holes are powered as active galactic nuclei (AGN), and AGN activity can be triggered by the stochastic accretion of gas or by gas inflows driven by galaxy mergers. Galaxy merger simulations make a series of predictions about the AGN that are triggered by mergers: (1) major mergers preferentially trigger higher-luminosity AGN, (2) minor mergers more often trigger AGN activity in one supermassive black hole while major mergers more often trigger AGN activity in both black holes in a merger, and (3) black hole mass growth peaks when the black holes approach the center (theory have been limited by the difficulty in defining a clean observational sample of AGN in galaxy mergers and the observational challenge of spatially resolving two AGN with small (dual AGN as a new observational tool that can be used to address how and when supermassive black hole mass growth occurs. A merger of two galaxies brings two supermassive black holes together, and the two black holes exist at kpc-scale separations for 100 Myr before ultimately merging. While the black holes are at kpc-scale separations, they are known as dual AGN when both of them are fueled as AGN and offset AGN when only one is fueled as an AGN. Since offset and dual AGN only occur in galaxy mergers, by their very definition, they provide a clean observational sample of black hole mass growth in galaxy mergers. The small, kpc-scale separations of offset and dual AGN also enable an observational test of black hole fueling near the centers of merger-remnant galaxies. The full potential of offset and dual AGN for such studies of black hole mass growth has not yet been realized, due to the small number of such systems known. To date, only 13 confirmed offset and dual AGN are

24 CFR 17.134 - Procedures for salary offset: when deductions may begin.

Science.gov (United States)

2010-04-01

... 24 Housing and Urban Development 1 2010-04-01 2010-04-01 false Procedures for salary offset: when deductions may begin. 17.134 Section 17.134 Housing and Urban Development Office of the Secretary, Department... Government Salary Offset Provisions § 17.134 Procedures for salary offset: when deductions may begin. (a...

20 CFR 361.11 - Procedures for salary offset: When deductions may begin.

Science.gov (United States)

2010-04-01

... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false Procedures for salary offset: When deductions... § 361.11 Procedures for salary offset: When deductions may begin. (a) Deductions to liquidate an... a debt is completed, offset shall be made from subsequent payments of any nature (e.g., final salary...

Fast optics for the Rutherford laser compression experiments

International Nuclear Information System (INIS)

Micholas, D.J.

1976-12-01

The compression chamber optical system proposed for the Rutherford Laboratory Laser compression experiments is described. The system corrects for longitudinal spherical aberration giving a final spot size approximately 15 μm. This could theoretically be improved. The two laser beams are focused via a pair of F/1.2 aspheric lenses onto a double-pass 'clam shell' aspheric mirror system. An analysis of the lens and mirror system is given and compared with an alternative ellipsoidal system already developed. The problems of manufacturing aspheric lenses to operate at 1.06 μm are outlined and an alternative novel approach to this design given. (author)

Measurement of the spectral shift of the 3d→4p transitions in Ar+, Cl+ and S+ by means of collinear fast-beam laser spectroscopy

International Nuclear Information System (INIS)

Eichhorn, A.

1981-01-01

The spectral shift of the 3d→4p transitions in Ar + ( 36 Ar + and 40 Ar + ) Cl + ( 35 Cl + and 37 Cl + ) and S + ( 32 S + + 34 S + ) were measured by means of collinear fast-beam laser spectroscopy. Since the volume effect is neglectible only the normal and specific mass effect give contributions to the spectral shift. (BEF)

Policy development for environmental licensing and biodiversity offsets in Latin America.

Directory of Open Access Journals (Sweden)

Ana Villarroya

Full Text Available Attempts to meet biodiversity goals through application of the mitigation hierarchy have gained wide traction globally with increased development of public policy, lending standards, and corporate practices. With interest in biodiversity offsets increasing in Latin America, we seek to strengthen the basis for policy development through a review of major environmental licensing policy frameworks in Argentina, Brazil, Chile, Colombia, Mexico, Peru and Venezuela. Here we focused our review on an examination of national level policies to evaluate to which degree current provisions promote positive environmental outcomes. All the surveyed countries have national-level Environmental Impact Assessment laws or regulations that cover the habitats present in their territories. Although most countries enable the use of offsets only Brazil, Colombia, Mexico and Peru explicitly require their implementation. Our review has shown that while advancing quite detailed offset policies, most countries do not seem to have strong requirements regarding impact avoidance. Despite this deficiency most countries have a strong foundation from which to develop policy for biodiversity offsets, but several issues require further guidance, including how best to: (1 ensure conformance with the mitigation hierarchy; (2 identify the most environmentally preferable offsets within a landscape context; (3 determine appropriate mitigation replacement ratios; and (4 ensure appropriate time and effort is given to monitor offset performance.

Policy development for environmental licensing and biodiversity offsets in Latin America.

Science.gov (United States)

Villarroya, Ana; Barros, Ana Cristina; Kiesecker, Joseph

2014-01-01

Attempts to meet biodiversity goals through application of the mitigation hierarchy have gained wide traction globally with increased development of public policy, lending standards, and corporate practices. With interest in biodiversity offsets increasing in Latin America, we seek to strengthen the basis for policy development through a review of major environmental licensing policy frameworks in Argentina, Brazil, Chile, Colombia, Mexico, Peru and Venezuela. Here we focused our review on an examination of national level policies to evaluate to which degree current provisions promote positive environmental outcomes. All the surveyed countries have national-level Environmental Impact Assessment laws or regulations that cover the habitats present in their territories. Although most countries enable the use of offsets only Brazil, Colombia, Mexico and Peru explicitly require their implementation. Our review has shown that while advancing quite detailed offset policies, most countries do not seem to have strong requirements regarding impact avoidance. Despite this deficiency most countries have a strong foundation from which to develop policy for biodiversity offsets, but several issues require further guidance, including how best to: (1) ensure conformance with the mitigation hierarchy; (2) identify the most environmentally preferable offsets within a landscape context; (3) determine appropriate mitigation replacement ratios; and (4) ensure appropriate time and effort is given to monitor offset performance.

Diode Lasers used in Plastic Welding and Selective Laser Soldering - Applications and Products

Science.gov (United States)

Reinl, S.

Aside from conventional welding methods, laser welding of plastics has established itself as a proven bonding method. The component-conserving and clean process offers numerous advantages and enables welding of sensitive assemblies in automotive, electronic, medical, human care, food packaging and consumer electronics markets. Diode lasers are established since years within plastic welding applications. Also, soft soldering using laser radiation is becoming more and more significant in the field of direct diode laser applications. Fast power controllability combined with a contactless temperature measurement to minimize thermal damage make the diode laser an ideal tool for this application. These advantages come in to full effect when soldering of increasingly small parts in temperature sensitive environments is necessary.

Improved SAR Amplitude Image Offset Measurements for Deriving Three-Dimensional Coseismic Displacements

KAUST Repository

Wang, Teng; Jonsson, Sigurjon

2015-01-01

Offsets of synthetic aperture radar (SAR) images have played an important role in deriving complete three-dimensional (3-D) surface displacement fields in geoscientific applications. However, offset maps often suffer from multiple outliers and patch-like artifacts, because the standard offset-measurement method is a regular moving-window operation that does not consider the scattering characteristics of the ground. Here, we show that by focusing the offset measurements on predetected strong reflectors, the reliability and accuracy of SAR offsets can be significantly improved. Application to the 2011 Van (Turkey) earthquake reveals a clear deformation signal from an otherwise decorrelated interferogram, making derivation of the 3-D coseismic displacement field possible. Our proposed method can improve mapping of coseismic deformation and other ground displacements, such as glacier flow and landslide movement when strong reflectors exist.

Improved SAR Amplitude Image Offset Measurements for Deriving Three-Dimensional Coseismic Displacements

KAUST Repository

Wang, Teng

2015-02-03

Offsets of synthetic aperture radar (SAR) images have played an important role in deriving complete three-dimensional (3-D) surface displacement fields in geoscientific applications. However, offset maps often suffer from multiple outliers and patch-like artifacts, because the standard offset-measurement method is a regular moving-window operation that does not consider the scattering characteristics of the ground. Here, we show that by focusing the offset measurements on predetected strong reflectors, the reliability and accuracy of SAR offsets can be significantly improved. Application to the 2011 Van (Turkey) earthquake reveals a clear deformation signal from an otherwise decorrelated interferogram, making derivation of the 3-D coseismic displacement field possible. Our proposed method can improve mapping of coseismic deformation and other ground displacements, such as glacier flow and landslide movement when strong reflectors exist.

A multi-laser system for a fast sampling Thomson scattering diagnostic

International Nuclear Information System (INIS)

Trost, P.K.; Carlstrom, T.N.; DeBoo, J.C.; Greenfield, C.M.; Hsieh, C.L.; Snider, R.T.

1990-10-01

A multi-laser system is being developed for the DIII-D Thomson scattering diagnostic. This system combines the beams from up to eight Nd:YAG lasers onto a common beamline in which the beams are nearly parallel and are all focused into a small, common area within the desired scattering volume. Each laser can be fired at a constant rate (20 Hz per laser) for a high average repetition rate, or together in a ''burst,'' which will give very high sampling rates (10--20 kHz) for short periods. The burst mode will be triggerable by plasma events, which will allow for study of transient phenomena, but will require non-periodic firing of the lasers. Beamline diagnostics include position sensitive detectors for computer controlled feedback alignment of the 35 m beamline, an image position detection system for monitoring the alignment of the collection lens to the scattering volume, and a 1-D reticon camera for divergence monitoring. The effects of the non-periodic firing of the lasers will be monitored with the reticon camera. 3 refs., 5 figs

Spatially Offset Active Galactic Nuclei. II. Triggering in Galaxy Mergers

Energy Technology Data Exchange (ETDEWEB)

Barrows, R. Scott; Comerford, Julia M. [Department of Astrophysical and Planetary Sciences, University of Colorado Boulder, Boulder, CO 80309 (United States); Greene, Jenny E. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Pooley, David, E-mail: Robert.Barrows@Colorado.edu [Department of Physics and Astronomy, Trinity University, San Antonio, TX 78212 (United States)

2017-04-01

Galaxy mergers are likely to play a role in triggering active galactic nuclei (AGNs), but the conditions under which this process occurs are poorly understood. In Paper I, we constructed a sample of spatially offset X-ray AGNs that represent galaxy mergers hosting a single AGN. In this paper, we use our offset AGN sample to constrain the parameters that affect AGN observability in galaxy mergers. We also construct dual-AGN samples with similar selection properties for comparison. We find that the offset AGN fraction shows no evidence for a dependence on AGN luminosity, while the dual-AGN fractions show stronger evidence for a positive dependence, suggesting that the merger events forming dual AGNs are more efficient at instigating accretion onto supermassive black holes than those forming offset AGNs. We also find that the offset and dual-AGN fractions both have a negative dependence on nuclear separation and are similar in value at small physical scales. This dependence may become stronger when restricted to high AGN luminosities, although a larger sample is needed for confirmation. These results indicate that the probability of AGN triggering increases at later merger stages. This study is the first to systematically probe down to nuclear separations of <1 kpc (∼0.8 kpc) and is consistent with predictions from simulations that AGN observability peaks in this regime. We also find that the offset AGNs are not preferentially obscured compared to the parent AGN sample, suggesting that our selection may be targeting galaxy mergers with relatively dust-free nuclear regions.

Spatially Offset Active Galactic Nuclei. II. Triggering in Galaxy Mergers

Science.gov (United States)

Barrows, R. Scott; Comerford, Julia M.; Greene, Jenny E.; Pooley, David

2017-04-01

Galaxy mergers are likely to play a role in triggering active galactic nuclei (AGNs), but the conditions under which this process occurs are poorly understood. In Paper I, we constructed a sample of spatially offset X-ray AGNs that represent galaxy mergers hosting a single AGN. In this paper, we use our offset AGN sample to constrain the parameters that affect AGN observability in galaxy mergers. We also construct dual-AGN samples with similar selection properties for comparison. We find that the offset AGN fraction shows no evidence for a dependence on AGN luminosity, while the dual-AGN fractions show stronger evidence for a positive dependence, suggesting that the merger events forming dual AGNs are more efficient at instigating accretion onto supermassive black holes than those forming offset AGNs. We also find that the offset and dual-AGN fractions both have a negative dependence on nuclear separation and are similar in value at small physical scales. This dependence may become stronger when restricted to high AGN luminosities, although a larger sample is needed for confirmation. These results indicate that the probability of AGN triggering increases at later merger stages. This study is the first to systematically probe down to nuclear separations of <1 kpc (˜0.8 kpc) and is consistent with predictions from simulations that AGN observability peaks in this regime. We also find that the offset AGNs are not preferentially obscured compared to the parent AGN sample, suggesting that our selection may be targeting galaxy mergers with relatively dust-free nuclear regions.

7 CFR 3.80 - Written agreement to repay debts as alternative to salary offset.

Science.gov (United States)

2010-01-01

... salary offset. 3.80 Section 3.80 Agriculture Office of the Secretary of Agriculture DEBT MANAGEMENT Federal Salary Offset § 3.80 Written agreement to repay debts as alternative to salary offset. (a) Notification by employee. The employee may propose, in response to a Notice of Intent to Offset Salary, a...

Update on markets for forestry offsets

International Nuclear Information System (INIS)

Neeff, T.; Eichler, L.; Deecke, I.; Fehse, J.

2007-01-01

This guide is an update of the book 'Guidebook to Markets and Commercialization of CDM forestry projects'. The document provides information on the development of CMD methodologies, projects registered and markets since the publication of the first version. In addition it introduces the emerging non-Kyoto markets, it presents a classification of the existing developments, it describes each market including the buyer's preferences and it discusses the use of standards and quality criteria and transaction costs. We focus on markets for offsets from developing countries, rather than domestic offsets in developed countries. Section 1 is an introduction to the topic and an overview of the most recent developments. Sections 2 and 3 look at recent experiences and market developments for CDM reforestation projects. These sections are meant to be an update of the above mentioned guidebook and thus refrain from an exhaustive description. Section 4 assesses non-Kyoto markets for carbon offsets from forestry projects. It includes a description of the various market schemes and types of buyers. The section attempts to provide the project developer with useful information for developing a project following buyer' requirements. Finally, section 5 puts the assessment of opportunities for forestry in the broader context of the larger carbon markets. The report then concludes with a comparison of advantages and disadvantages of the CDM and non-Kyoto schemes from the project developer's point of view

Collimated fast electron beam generation in critical density plasma

Energy Technology Data Exchange (ETDEWEB)

Iwawaki, T., E-mail: iwawaki-t@eie.eng.osaka-u.ac.jp; Habara, H.; Morita, K.; Tanaka, K. A. [Graduate School of Engineering, Osaka University, 2-1, Yamada-oka, Suita, Osaka 565-0871 (Japan); Baton, S.; Fuchs, J.; Chen, S. [LULI, CNRS-Ecole Polytechnique-Université Pierre et Marie Curie-CEA, 91128 Palaiseau (France); Nakatsutsumi, M. [LULI, CNRS-Ecole Polytechnique-Université Pierre et Marie Curie-CEA, 91128 Palaiseau (France); European X-Ray Free-Electron Laser Facility (XFEL) GmbH (Germany); Rousseaux, C. [CEA, DAM, DIF, F-91297 Arpajon (France); Filippi, F. [La SAPIENZA, University of Rome, Dip. SBAI, 00161 Rome (Italy); Nazarov, W. [School of Chemistry, University of St. Andrews, North Haugh, St. Andrews, Fife KY16 9ST, Scotland (United Kingdom)

2014-11-15

Significantly collimated fast electron beam with a divergence angle 10° (FWHM) is observed when an ultra-intense laser pulse (I = 10{sup 14 }W/cm{sup 2}, 300 fs) irradiates a uniform critical density plasma. The uniform plasma is created through the ionization of an ultra-low density (5 mg/c.c.) plastic foam by X-ray burst from the interaction of intense laser (I = 10{sup 14 }W/cm{sup 2}, 600 ps) with a thin Cu foil. 2D Particle-In-Cell (PIC) simulation well reproduces the collimated electron beam with a strong magnetic field in the region of the laser pulse propagation. To understand the physical mechanism of the collimation, we calculate energetic electron motion in the magnetic field obtained from the 2D PIC simulation. As the results, the strong magnetic field (300 MG) collimates electrons with energy over a few MeV. This collimation mechanism may attract attention in many applications such as electron acceleration, electron microscope and fast ignition of laser fusion.

Combining landscape-level conservation planning and biodiversity offset programs: a case study.

Science.gov (United States)

Underwood, Jared G

2011-01-01

Habitat loss is a major factor in the endangerment and extinction of species around the world. One promising strategy to balance continued habitat loss and biodiversity conservation is that of biodiversity offsets. However, a major concern with offset programs is their consistency with landscape-level conservation goals. While merging offset policies and landscape-level conservation planning is thought to provide advantages over a traditional disconnected approach, few such landscape-level conservation-offset plans have been designed and implemented, so the effectiveness of such a strategy remains uncertain. In this study, we quantitatively assess the conservation impact of combining landscape-level conservation planning and biodiversity offset programs by comparing regions of San Diego County, USA with the combined approach to regions with only an offset program. This comparison is generally very difficult due to a variety of complicating factors. We overcome these complications and quantify the benefits to rare and threatened species of implementing a combined approach by assessing the amount of each species' predicted distribution, and the number of documented locations, conserved in comparison to the same metric for areas with an offset policy alone. We found that adoption of the combined approach has increased conservation for many rare species, often 5-10 times more than in the comparison area, and that conservation has been focused in the areas most important for these species. The level of conservation achieved reduces uncertainty that these species will persist in the region into the future. This San Diego County example demonstrates the potential benefits of combining landscape-level conservation planning and biodiversity offset programs.

The spammed code offset method

NARCIS (Netherlands)

Skoric, B.; Vreede, de N.

2013-01-01

Helper data schemes are a security primitive used for privacy-preserving biometric databases and Physical Unclonable Functions. One of the oldest known helper data schemes is the Code Offset Method (COM). We propose an extension of the COM: the helper data is accompanied by many instances of fake

The spammed code offset method

NARCIS (Netherlands)

Skoric, B.; Vreede, de N.

2014-01-01

Helper data schemes are a security primitive used for privacy-preserving biometric databases and physical unclonable functions. One of the oldest known helper data schemes is the code offset method (COM). We propose an extension of the COM: the helper data are accompanied by many instances of fake

Sensor development and integration for robotized laser welding

NARCIS (Netherlands)

Iakovou, D.

2009-01-01

Laser welding requires fast and accurate positioning of the laser beam over the seam trajectory. The task of accurate positioning of the laser tools is performed by robotic systems. It is therefore necessary to teach the robot the path it has to follow. Seam teaching is implemented in several ways:

Upgrade of repetitive fast-heating fusion driver HAMA to implode a shell target by using diode pumped solid state laser

International Nuclear Information System (INIS)

MORI, Yoshitaka; NISHIMURA, Yasuhiko; Nakayama, Suisei; HANAYAMA, Ryohei; ISHII, Katsuhiro; SEKINE, Takashi; SATO, Nakahiro; KURITA, Takashi; KAWASHIMA, Toshiyuki; KAN, Hirofumi; KOMEDA, Osamu; NAKAMURA, Naoki; KONDO, Takuya; FUJINE, Manabu; SUNAHARA, Atsushi; MIURA, Eisuke; AZUMA, Hirozumi; HIOKI, Tatsumi; KAKENO, Mitsutaka; KAJINO, Tsutomu

2016-01-01

The HAMA is 1-Hz fast heating fusion driver pumped by a 10 J second-harmonic of diode-pumped Nd:glass laser: KURE-1. We have upgraded HAMA to realize an implosion of spherical shell target by using a remaining fundamental beam from KURE-1. This beam of 6 J/1 Hz is transported to the current counter irradiation system. The resulting beam includes three pulses in sequence: 2.2 J/15 ns and 0.7 J/300 ps for implosion, and 0.5 J/ 190 fs for heating. We estimate the implosion dynamics from 1-D radiation hydrodynamic code (START- 1D). It indicates a possibility of tailored-pulse implosion by optimizing the beam spot sizes of imploding beams on the target surface. This upgrade leads to a demonstration of repetitive implosion and additional heating of a spherical shell target in accordance with a repetition of laser operation and that of a target injection system. (paper)

High-performance OPCPA laser system

International Nuclear Information System (INIS)

Zuegel, J.D.; Bagnoud, V.; Bromage, J.; Begishev, I.A.; Puth, J.

2006-01-01

Optical parametric chirped-pulse amplification (OPCPA) is ideally suited for amplifying ultra-fast laser pulses since it provides broadband gain across a wide range of wavelengths without many of the disadvantages of regenerative amplification. A high-performance OPCPA system has been demonstrated as a prototype for the front end of the OMEGA Extended Performance (EP) Laser System. (authors)

High-performance OPCPA laser system

Energy Technology Data Exchange (ETDEWEB)

Zuegel, J.D.; Bagnoud, V.; Bromage, J.; Begishev, I.A.; Puth, J. [Rochester Univ., Lab. for Laser Energetics, NY (United States)

2006-06-15

Optical parametric chirped-pulse amplification (OPCPA) is ideally suited for amplifying ultra-fast laser pulses since it provides broadband gain across a wide range of wavelengths without many of the disadvantages of regenerative amplification. A high-performance OPCPA system has been demonstrated as a prototype for the front end of the OMEGA Extended Performance (EP) Laser System. (authors)

Design of fundamental building blocks for fast binary readout CMOS sensors used in high-energy physics experiments

Energy Technology Data Exchange (ETDEWEB)

Degerli, Yavuz [CEA Saclay, IRFU/SEDI, 91191 Gif-sur-Yvette Cedex (France)], E-mail: degerli@cea.fr

2009-04-21

In this paper, design details of key building blocks for fast binary readout CMOS monolithic active pixel sensors developed for charged particle detection are presented. Firstly, an all-NMOS pixel architecture with in-pixel amplification and reset noise suppression which allows fast readout is presented. This pixel achieves high charge-to-voltage conversion factors (CVF) using a few number of transistors inside the pixel. It uses a pre-amplifying stage close to the detector and a simple double sampling (DS) circuitry to store the reset level of the detector. The DS removes the offset mismatches of amplifiers and the reset noise of the detector. Offset mismatches of the source follower are also corrected by a second column-level DS stage. The second important building block of these sensors, a low-power auto-zeroed column-level discriminator, is also presented. These two blocks transform the charge of the impinging particle into binary data. Finally, some experimental results obtained on CMOS chips designed using these blocks are presented.

Determination of the Thermal Offset of the Eppley Precision Spectral Pyranometer

Science.gov (United States)

Haeffelin, Martial; Kato, Seiji; Smith, Amie M.; Rutledge, C. Ken; Charlock, Thomas P.; Mahan, J. Robert

2001-01-01

Eppley's precision spectral pyranometer (PSP) is used in networks around the world to measure downwelling diffuse and global solar irradiance at the surface of the Earth. In recent years several studies have shown significant discrepancy between irradiances measured by pyranometers and those computed by atmospheric radiative transfer models. Pyranometer measurements have been questioned because observed diffuse irradiances sometimes are below theoretical minimum values for a pure molecular atmosphere, and at night the instruments often produce nonzero signals ranging between + 5 and - 10 W/sq m. We install thermistor sondes in the body of a PSP as well as on its inner dome to monitor the temperature gradients within the instrument, and we operate a pyrgeometer (PIR) instrument side by side with the PSP. We derive a relationship between the PSP output and thermal radiative exchange by the dome and the detector and a relationship between the PSP output and the PIR thermopile output (net-IR). We determine the true PSP offset by quickly capping the instrument at set time intervals. For a ventilated and shaded PSP, the thermal offset can reach - 15 W/sq m under clear skies, whereas it remains close to zero for low overcast clouds. We estimate the PSP thermal offset by two methods: (1) using the PSP temperatures and (2) using the PIR net-IR signal. The offset computed from the PSP temperatures yields a reliable estimate of the true offset (+/- 1 W/sq m). The offset computed from net-IR is consistent with the true offset at night and under overcast skies but predicts only part of the true range under clear skies.

Strain and temperature characteristics of the LP11 mode based on a few-mode fiber Bragg grating and core-offset splicing

Science.gov (United States)

Jin, Wenxing; Xu, Yao; Jiang, Youchao; Wu, Yue; Yao, Shuzhi; Xiao, Shiying; Qi, Yanhui; Ren, Wenhua; Jian, Shuisheng

2018-02-01

We propose and demonstrate a ring fiber laser based on a few-mode fiber Bragg grating for strain and temperature sensing using only the LP11 mode. The core-offset splicing method is used to ensure effective coupling from the fundamental mode to the LP11 mode. A stable erbium-doped fiber laser operating as a single LP11 mode with a 3 dB linewidth of about 0.02 nm and an optical signal-to-noise ratio over 42 dB is achieved by appropriately adjusting the polarization controller between the optical circulator and the few-mode fiber Bragg grating. A high axial strain sensitivity of 0.8778 pm μ\\varepsilon-1 and a temperature sensitivity of 9.9214 pm °C-1 are achieved with the advantages of all-fiber, simple construction and easy control.

Semiconductor lasers stability, instability and chaos

CERN Document Server

Ohtsubo, Junji

2017-01-01

This book describes the fascinating recent advances made concerning the chaos, stability and instability of semiconductor lasers, and discusses their applications and future prospects in detail. It emphasizes the dynamics in semiconductor lasers by optical and electronic feedback, optical injection, and injection current modulation. Applications of semiconductor laser chaos, control and noise, and semiconductor lasers are also demonstrated. Semiconductor lasers with new structures, such as vertical-cavity surface-emitting lasers and broad-area semiconductor lasers, are intriguing and promising devices. Current topics include fast physical number generation using chaotic semiconductor lasers for secure communication, development of chaos, quantum-dot semiconductor lasers and quantum-cascade semiconductor lasers, and vertical-cavity surface-emitting lasers. This fourth edition has been significantly expanded to reflect the latest developments. The fundamental theory of laser chaos and the chaotic dynamics in se...

Digital frequency offset-locked He–Ne laser system with high beat frequency stability, narrow optical linewidth and optical fibre output

Science.gov (United States)

Sternkopf, Christian; Manske, Eberhard

2018-06-01

We report on the enhancement of a previously-presented heterodyne laser source on the basis of two phase-locked loop (PLL) frequency coupled internal-mirror He–Ne lasers. Our new system consists of two digitally controlled He–Ne lasers with slightly different wavelengths, and offers high-frequency stability and very narrow optical linewidth. The digitally controlled system has been realized by using a FPGA controller and transconductance amplifiers. The light of both lasers was coupled into separate fibres for heterodyne interferometer applications. To enhance the laser performance we observed the sensitivity of both laser tubes to electromagnetic noise from various laser power supplies and frequency control systems. Furthermore, we describe how the linewidth of a frequency-controlled He–Ne laser can be reduced during precise frequency stabilisation. The digitally controlled laser source reaches a standard beat frequency deviation of less than 20 Hz (with 1 s gate time) and a spectral full width at half maximum (FWHM) of the beat signal less than 3 kHz. The laser source has enough optical output power to serve a fibre-coupled multi axis heterodyne interferometer. The system can be adjusted to output beat frequencies in the range of 0.1 MHz–20 MHz.

Pulsar Pair Cascades in Magnetic Fields with Offset Polar Caps

Science.gov (United States)

Harding, Alice K.; Muslimov, Alex G.

2012-01-01

Neutron star magnetic fields may have polar caps (PC) that are offset from the dipole axis, through field-line sweepback near the light cylinder or non-symmetric currents within the star. The effects of such offsets on electron-positron pair cascades are investigated, using simple models of dipole magnetic fields with small distortions that shift the PCs by different amounts or directions. Using a Monte Carlo pair cascade simulation, we explore the changes in the pair spectrum, multiplicity and energy flux across the PC, as well as the trends in pair flux and pair energy flux with spin-down luminosity, L(sub sd). We also give an estimate of the distribution of heating flux from returning positrons on the PC for different offsets. We find that even modest offsets can produce significant increases in pair multiplicity, especially for pulsars that are near or beyond the pair death lines for centered PCs, primarily because of higher accelerating fields. Pair spectra cover several decades in energy, with the spectral range of millisecond pulsars (MSPs) two orders of magnitude higher than for normal pulsars, and PC offsets allow significant extension of all spectra to lower pair energies. We find that the total PC pair luminosity L(sub pair) is proportional to L(sub sd), with L(sub pair) approximates 10(exp -3) L(sub sd) for normal pulsars and L(sub pair) approximates 10(exp -2) L(sub sd) for MSPs. Remarkably, the total PC heating luminosity for even large offsets increases by less than a factor of two, even though the PC area increases by much larger factors, because most of the heating occurs near the magnetic axis.

Fast method for geometric calibration of detectors and matching testing between two detectors

International Nuclear Information System (INIS)

Pechenova, O.Yu.

2002-01-01

A fast method of geometric calibration of detectors has been proposed. The main idea of this method is to determine offsets by fitting the real data distribution by analytic functions which describe the motion of one detector relative to the other one. This method can be applicable to offsets determination for one detector relative to the other detector or for one part of the detector relative to its other part. The detectors should be placed perpendicular to the beam axis. The form of analytic functions depends on the geometry of the experiment and direction of the coordinate axes. The analytic functions have been obtained using the rotation matrices. This method can be applied to the matching testing between two detectors

Temperature Induced Voltage Offset Drifts in Silicon Carbide Pressure Sensors

Science.gov (United States)

Okojie, Robert S.; Lukco, Dorothy; Nguyen, Vu; Savrun, Ender

2012-01-01

We report the reduction of transient drifts in the zero pressure offset voltage in silicon carbide (SiC) pressure sensors when operating at 600 C. The previously observed maximum drift of +/- 10 mV of the reference offset voltage at 600 C was reduced to within +/- 5 mV. The offset voltage drifts and bridge resistance changes over time at test temperature are explained in terms of the microstructure and phase changes occurring within the contact metallization, as analyzed by Auger electron spectroscopy and field emission scanning electron microscopy. The results have helped to identify the upper temperature reliable operational limit of this particular metallization scheme to be 605 C.

Physical mechanisms of SiNx layer structuring with ultrafast lasers by direct and confined laser ablation

International Nuclear Information System (INIS)

Rapp, S.; Heinrich, G.; Wollgarten, M.; Huber, H. P.; Schmidt, M.

2015-01-01

In the production process of silicon microelectronic devices and high efficiency silicon solar cells, local contact openings in thin dielectric layers are required. Instead of photolithography, these openings can be selectively structured with ultra-short laser pulses by confined laser ablation in a fast and efficient lift off production step. Thereby, the ultrafast laser pulse is transmitted by the dielectric layer and absorbed at the substrate surface leading to a selective layer removal in the nanosecond time domain. Thermal damage in the substrate due to absorption is an unwanted side effect. The aim of this work is to obtain a deeper understanding of the physical laser-material interaction with the goal of finding a damage-free ablation mechanism. For this, thin silicon nitride (SiN x ) layers on planar silicon (Si) wafers are processed with infrared fs-laser pulses. Two ablation types can be distinguished: The known confined ablation at fluences below 300 mJ/cm 2 and a combined partial confined and partial direct ablation at higher fluences. The partial direct ablation process is caused by nonlinear absorption in the SiN x layer in the center of the applied Gaussian shaped laser pulses. Pump-probe investigations of the central area show ultra-fast reflectivity changes typical for direct laser ablation. Transmission electron microscopy results demonstrate that the Si surface under the remaining SiN x island is not damaged by the laser ablation process. At optimized process parameters, the method of direct laser ablation could be a good candidate for damage-free selective structuring of dielectric layers on absorbing substrates

25 CFR 513.30 - When may the Commission use salary offset to collect debts?

Science.gov (United States)

2010-04-01

... 25 Indians 2 2010-04-01 2010-04-01 false When may the Commission use salary offset to collect... GENERAL PROVISIONS DEBT COLLECTION Salary Offset § 513.30 When may the Commission use salary offset to... salary offset under the authority of: 5 U.S.C. 5514; 31 U.S.C. 3716; 5 CFR part 550, subpart K; 31 CFR...

36 CFR 1201.33 - How will NARA coordinate salary offsets with other agencies?

Science.gov (United States)

2010-07-01

... salary offsets with other agencies? 1201.33 Section 1201.33 Parks, Forests, and Public Property NATIONAL ARCHIVES AND RECORDS ADMINISTRATION GENERAL RULES COLLECTION OF CLAIMS Salary Offset § 1201.33 How will NARA coordinate salary offsets with other agencies? (a) Responsibilities of NARA as the creditor agency...

Development of electrical excited CO2-laser with transversal gas flow as well an axial flowed CO2-laser for material treatment, in particular for cutting

International Nuclear Information System (INIS)

Wollermann-Windgasse, R.; Ackermann, F.

1987-04-01

The project describes the development of a new generation of CO 2 -lasers using high frequency discharge (13.56 MHz) for laser excitation by capacitive dielectrical input. HF-excitation has a lot of advantages compared with direct current technology, these are higher electrical input power into the plasma, better homogeneity and stability of discharges. In addition to this, HF-excitation shows excellent possibilities for pulsing and modulation. As a result of this, there are compact powerful laser systems with the possibility of scaling up to the multi-kW-range. The examination included fast transversal flowed as well as fast axial flowed systems. In the end of this project development prototypes with laser output power of 1000 W, 1500 W and 3000 W were available. Detailed attempts of application show that these lasers on grounds of excellent laser output quality and controlability of laser power specifically to each process make possible new ways for material treatment by laser. (orig./HP) [de

The Determinants Of United States Government Policy And Practice Towards Offsets In International Trade

National Research Council Canada - National Science Library

Milligan, Joseph

2003-01-01

.... Offsets are increasing as a percentage of defense exports. Because US industry leads worldwide defense exports, US offsets policy and the potential impact of offsets on US national security are highly significant...

A Review of Offset Programs: Trading Systems, Funds, Protocols, Standards and Retailers

Energy Technology Data Exchange (ETDEWEB)

Kollmuss, Anja; Lazarus, Michael; Lee, Carrie; Polycarp, Clifford

2008-11-15

Carbon or greenhouse gas (GHG) offsets have long been promoted as an important element of a comprehensive climate policy approach. Offset programs can reduce the overall cost of achieving a given emission goal by enabling emission reductions to occur where costs are lower. Furthermore, offsets have the potential to deliver sustainability co-benefits, spurred through technology development and transfer, and to develop human and institutional capacity for reducing emissions in sectors and locations not included in a cap and trade or a mandatory government policy. However, offsets can pose a risk to the environmental integrity of climate actions, especially if issues surrounding additionality, permanence, leakage, quantification and verification are not adequately addressed. The challenge for policymakers is clear: to design offset programs and policies that can maximize their potential benefits while minimizing their potential risks. The goal of this review is to provide an up-to-date analysis and synthesis of the most influential offset programs and activities, to reflect on lessons learned, and thus to inform participants and designers of current and future offset programs. Our intention is to periodically update this review to stay abreast of ongoing developments, and to develop a website portal to make this information more accessible. This version targets programs that meet one or more of the following criteria: - a significant volume of credit transactions occurring or anticipated; - an established set of rules or protocols - path-breaking, novel or otherwise notable initiatives or important lessons learned

Optimisation of 1.3 μm strained-layer semiconductor lasers

International Nuclear Information System (INIS)

Pacey, C.

1999-03-01

The objectives of the research undertaken have been to investigate the properties of semiconductor lasers operating at around 1.3 μm. The aim of the investigation is to suggest modifications which give rise to improved operating characteristics especially in the high temperature (approaching 85 deg. C) range. The investigation can be divided into 2 sections: a theoretical approach and an experimental section. The theoretical study examined the performance of compressively strained InGaAsP/InP multiple quantum-well lasers emitting at 1.3 μm. in order to investigate the important factors and trends in the threshold current density and differential gain with strain, well width and well number. Structures with a fixed compressive strain of 1% but variable well width, and also with a fixed well width but variable strain from 0% to 1.4% have been considered. It has been found that there is little benefit to having compressive strains greater than 1%. For structures with a fixed 1% compressive strain and unstrained barriers, an optimum structure for lowest threshold current density and a high differential gain has been found to consist of six 35 A quantum-wells. In addition, compensated strain (CS) structures with compressive wells and tensile barriers have been examined. It is shown that the conduction band offset can be significantly increased and the valence band offset reduced in such structures, to give band-offset ratios comparable with aluminium based 1.3 μm devices. The gain calculations performed suggest that there is little degradation in the threshold carrier density or differential gain due to these alterations in the band offsets; and hence a better laser performance is expected due to a reduction in thermal leakage currents due to the improved electron confinement. The experimental study concentrates on looking at certain key design parameters to investigate their effect on the laser performance. These design parameters range from the number of quantum

Kinematics of reflections in subsurface offset and angle-domain image gathers

Science.gov (United States)

Dafni, Raanan; Symes, William W.

2018-05-01

Seismic migration in the angle-domain generates multiple images of the earth's interior in which reflection takes place at different scattering-angles. Mechanically, the angle-dependent reflection is restricted to happen instantaneously and at a fixed point in space: Incident wave hits a discontinuity in the subsurface media and instantly generates a scattered wave at the same common point of interaction. Alternatively, the angle-domain image may be associated with space-shift (regarded as subsurface offset) extended migration that artificially splits the reflection geometry. Meaning that, incident and scattered waves interact at some offset distance. The geometric differences between the two approaches amount to a contradictory angle-domain behaviour, and unlike kinematic description. We present a phase space depiction of migration methods extended by the peculiar subsurface offset split and stress its profound dissimilarity. In spite of being in radical contradiction with the general physics, the subsurface offset reveals a link to some valuable angle-domain quantities, via post-migration transformations. The angle quantities are indicated by the direction normal to the subsurface offset extended image. They specifically define the local dip and scattering angles if the velocity at the split reflection coordinates is the same for incident and scattered wave pairs. Otherwise, the reflector normal is not a bisector of the opening angle, but of the corresponding slowness vectors. This evidence, together with the distinguished geometry configuration, fundamentally differentiates the angle-domain decomposition based on the subsurface offset split from the conventional decomposition at a common reflection point. An asymptotic simulation of angle-domain moveout curves in layered media exposes the notion of split versus common reflection point geometry. Traveltime inversion methods that involve the subsurface offset extended migration must accommodate the split geometry

Growth of superconducting MgB2 films by pulsed-laser deposition using a Nd-YAG laser

International Nuclear Information System (INIS)

Badica, P; Togano, K; Awaji, S; Watanabe, K

2006-01-01

Thin films of MgB 2 on r-cut Al 2 O 3 substrates have been grown by pulsed-laser deposition (PLD) using a Nd-YAG laser (fourth harmonic-266 nm) instead of the popular KrF excimer laser. The growth window to obtain superconducting films is laser energy 350-450 mJ and vacuum pressure with Ar-buffer gas of 1-8/10 Pa (initial background vacuum 0.5-1 x 10 -3 Pa). Films were deposited at room temperature and post-annealed in situ and ex situ at temperatures of 500-780 0 C and up to 1 h. Films are randomly oriented with maximum critical temperature (offset of resistive transition) of 27 K. SEM/TEM/EDS investigations show that they are mainly composed of small sphere-like particles (≤20 nm), and contain oxygen and some carbon, uniformly distributed in the flat matrix, but the amount of Mg and/or oxygen is higher in the aggregates-droplets (100-1000 nm) observed on the surface of the film's matrix. Some aspects of the processing control and dependences on film characteristics are discussed. The technique is promising for future development of coated conductors

Optimizing laser crater enhanced Raman spectroscopy.

Science.gov (United States)

Lednev, V N; Sdvizhenskii, P A; Grishin, M Ya; Filichkina, V A; Shchegolikhin, A N; Pershin, S M

2018-03-20

Raman signal enhancement by laser crater production was systematically studied for 785 nm continuous wave laser pumping. Laser craters were produced in L-aspartic acid powder by a nanosecond pulsed solid state neodymium-doped yttrium aluminum garnet laser (532 nm, 8 ns, 1 mJ/pulse), while Raman spectra were then acquired by using a commercial spectrometer with 785 nm laser beam pumping. The Raman signal enhancement effect was studied in terms of the number of ablating pulses used, the lens-to-sample distance, and the crater-center-laser-spot offset. The influence of the experiment parameters on Raman signal enhancement was studied for different powder materials. Maximum Raman signal enhancement reached 11 fold for loose powders but decreased twice for pressed tablets. Raman signal enhancement was demonstrated for several diverse powder materials like gypsum or ammonium nitrate with better results achieved for the samples tending to give narrow and deep craters upon the laser ablation stage. Alternative ways of cavity production (steel needle tapping and hole drilling) were compared with the laser cratering technique in terms of Raman signal enhancement. Drilling was found to give the poorest enhancement of the Raman signal, while both laser ablation and steel needle tapping provided comparable results. Here, we have demonstrated for the first time, to the best of our knowledge, that a Raman signal can be enhanced 10 fold with the aid of simple cavity production by steel needle tapping in rough highly reflective materials. Though laser crater enhancement Raman spectroscopy requires an additional pulsed laser, this technique is more appropriate for automatization compared to the needle tapping approach.

Fast ignition studies at Osaka University

International Nuclear Information System (INIS)

Tanaka, K. A.

2007-01-01

After the invention of the chirped pulse amplification technique [1], the extreme conditions of matters have become available in laboratory spaces and can be studied with the use of ultra intense laser pulse (UILP) with a high energy. One such example is the fast ignition [2] where UILP is used to heat a highly compressed fusion fuel core within 1-10 pico-seconds before the core disassembles. It is predicted possible with use of 50-100 kJ lasers for both imploding the fuel and heating [2] to attain a large fusion gain. Fast ignition was shown to be a promising new scheme for laser fusion [3] with a PW (= 10 1 5 W) UILP and GEKKO XII laser systems at Osaka. Many new physics have been found with use of UILP in a relativistic parameter regime during the process of the fast ignition studies. UILP can penetrate into over-dense plasma for a couple hundred microns distance with a self-focusing and relativistic transparency effects. Hot electrons of 1-100 MeV can be easily created and are under studies for its spectral and emission angle controls. Strong magnetic fields of 10's of MGauss are created to guide these hot electrons along the target surface [4]. Based on these results, a new and largest UILP laser machine of 10 kJ energy at PW UILP peak power is under construction to test if we can achieve the sub-ignition fusion condition at Osaka University. The machine requires challenging optical technologies such as large size (0.9 m) gratings, tiling these gratings for UILP compression; segmenting four large UILP beams to obtain diffraction limited focal spot. We would like to over-view all of these activities. References [1]D. STRICKLAND and G. MOUROU, Opt. Commun., 56, 219 (1985) [2] S. ATZENI et al., Phys Plasmas, 6, 3316 (1999) [3] R. KODAMA, K.A. TANAKA et al., Nature, 418, 933 (2002) [4] A.L. LEI, K.A. TANAKA et al., Phys. Rev. Lett., 96, 255006(2006) ; H. HABARA, K.A. TANAKA et al., Phys. Rev. Lett., 97, 095004 (2006)

Axially perpendicular offset Raman scheme for reproducible measurement of housed samples in a noncircular container under variation of container orientation.

Science.gov (United States)

Duy, Pham K; Chang, Kyeol; Sriphong, Lawan; Chung, Hoeil

2015-03-17

An axially perpendicular offset (APO) scheme that is able to directly acquire reproducible Raman spectra of samples contained in an oval container under variation of container orientation has been demonstrated. This scheme utilized an axially perpendicular geometry between the laser illumination and the Raman photon detection, namely, irradiation through a sidewall of the container and gathering of the Raman photon just beneath the container. In the case of either backscattering or transmission measurements, Raman sampling volumes for an internal sample vary when the orientation of an oval container changes; therefore, the Raman intensities of acquired spectra are inconsistent. The generated Raman photons traverse the same bottom of the container in the APO scheme; the Raman sampling volumes can be relatively more consistent under the same situation. For evaluation, the backscattering, transmission, and APO schemes were simultaneously employed to measure alcohol gel samples contained in an oval polypropylene container at five different orientations and then the accuracies of the determination of the alcohol concentrations were compared. The APO scheme provided the most reproducible spectra, yielding the best accuracy when the axial offset distance was 10 mm. Monte Carlo simulations were performed to study the characteristics of photon propagation in the APO scheme and to explain the origin of the optimal offset distance that was observed. In addition, the utility of the APO scheme was further demonstrated by analyzing samples in a circular glass container.

Multi-peta-watt laser performances

International Nuclear Information System (INIS)

Reichart, A.; Blanchot, N.; Nicolaizeau, M.; Ribeyre, X.; Bettinger, A.

2000-01-01

A multi-Peta-watt laser inside the 'Ligne d'integration laser' building is studied. We present simulations of the different amplification stages to reach broadband 10 kJ pulses in order to obtain a multi-Peta-watt laser beam. The results for preamplifier and power amplifier are detailed. Challenges of a multi-Peta-watt system are to increase the limit of compressed energy an order of magnitude, to perform a focal spot around 100 μm for Fast Ignitor applications, and to provide a temporal contrast better than 10 10 , for X-ray laser and plasma interaction applications. These first 1-D calculations are helpful for the design of a multi-Peta-watt laser. (authors)

Activation of ion implanted Si for backside processing by Ultra-fast Laser Thermal Annealing: Energy homogeneity and micro-scale sheet resistance

DEFF Research Database (Denmark)

Huet, K.; Lin, Rong; Boniface, C

2009-01-01

In this paper ion activation of implanted silicon using ultra-fast laser thermal annealing (LTA) process was discussed. The results stated that there was high dopant activation using LTA process for over 70%, excellent within shot activation uniformity, and there was a possibility for overlap...... parameter optimization. It was observed that, for activation LTA process, shallow box-shaped profiles- high diffusivity of B in liquids and high-temperatures was observed only near the surface in a submicrosecond timescale. Possible solutions were suggested as to low-cost and high-end for overlap...

22 CFR 309.18 - Voluntary repayment agreements as an alternative to salary offset.

Science.gov (United States)

2010-04-01

... to salary offset. 309.18 Section 309.18 Foreign Relations PEACE CORPS DEBT COLLECTION Salary Offset § 309.18 Voluntary repayment agreements as an alternative to salary offset. (a) In response to a notice of intent, an employee may propose a written agreement to repay the debt as an alternative to salary...

40 CFR 13.23 - Salary offset when EPA is not the creditor agency.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Salary offset when EPA is not the... CLAIMS COLLECTION STANDARDS Administrative Offset § 13.23 Salary offset when EPA is not the creditor... period. (4) Unless the employee has consented in writing to the salary deductions or signed a statement...

Absorption of turbulent laser plasma radiation

International Nuclear Information System (INIS)

Silin, V.P.

1979-02-01

Some theoretical results relating to the interaction of high-power laser radiation with a plasma are presented including the development of a theory of parametric instabilities in an inhomogeneous laser plasma which shows that the size of the spatial region in which the turbulent state develops is comparable with the characteristic dimension of a several-fold fluctuation in the plasma density close to its critical value. The conditions are identified under which parametric turbulence gives an anomalous effective collision frequency substantially greater than the normal electron-ion collision frequency. Even during the build-up of strong parametric turbulence, conditions are found for the development of anomalous dissipation which results in heating of the bulk of the electrons. Under opposite conditions, the dynamic behaviour due to the influence of the ponderomotive forces associated with the p component of the radiation field shows that under slow plasma flow conditions, a considerable proportion of the laser energy absorbed by the plasma is transferred to the fast electrons. Suppression of the Cherenkov mechanism for generation of the fast electron component is observed on transition to fast plasma flow conditions. (author)

Laser modulator for LISA pathfinder

Science.gov (United States)

Voland, C.; Lund, G.; Coppoolse, W.; Crosby, P.; Stadler, M.; Kudielka, K.; Özkan, C.

2017-11-01

LISA Pathfinder is an ESA experiment to demonstrate the key technologies needed for the LISA mission to detect gravitational waves in space. The LISA Pathfinder spacecraft represents one arm of the LISA interferometer, containing an optical metrology system and two proof masses as inertial references for the drag-free control system. The LISA Pathfinder payload consists of two drag-free floating test masses located in the inertial sensors with their control electronics and an optical metrology subsystem. The optical metrology subsystem monitors the movement of both test masses relative to each other and to the spacecraft with very high sensitivity and resolution. This is achieved with a heterodyne Mach- Zehnder interferometer. This interferometer requires as input two coherent laser beams with a heterodyne frequency difference of a few kHz. To generate the two laser beams with a heterodyne frequency difference a Nd:YAG laser is used together with the Laser Modulator. The Nd:YAG laser generates a single coherent laser signal at a wavelength of 1064nm which is fibre coupled to the Laser Modulator. The Laser Modulator then generates the two optical beams with the required heterodyne frequency offset. In addition, the Laser Modulator is required to perform laser amplitude stabilization and optical path difference control for the two optical signals. The Laser Modulator consists of an optical unit - the LMU - and RF synthesiser, power amplification and control electronics. These electronics are all housed in the Laser Modulator Electronics (LME). The LMU has four primary functions: • Splitting of the input laser beam into two paths for later superposition in the interferometer. • Applying different frequency shifts to each of the beams. • Providing amplitude modulation control to each of the beams. • Providing active control of the optical path length difference between the two optical paths. The present paper describes the design and performance of the LMU

Japanese citizens’ preferences regarding voluntary carbon offsets: an experimental social survey of Yokohama and Kitakyushu

International Nuclear Information System (INIS)

Nakamura, Hidenori; Kato, Takaaki

2013-01-01

This study uses an experimental social survey in two large Japanese cities to explore citizens’ attitudes toward international voluntary carbon offsetting that encourages low carbon development in developing countries. In particular, the study focuses on whether the offsetting is a contribution to meet national target of greenhouse gas (GHG) emissions reduction under the Kyoto Protocol or reduction beyond the national target, using Kyoto credits generated from climate change mitigation projects in developing countries. The study finds that around 40% of the survey respondents chose real carbon offsetting over a gift certificate as compensation for their participation in the survey, around half of whom chose carbon offsetting contribution to the world. However, most of the current Japanese carbon offsetting providers utilise only the carbon offsetting contribution to the Japanese government. Thus, Japanese citizens have significant untapped potential for undertaking more carbon offsetting to meet targets other than national targets. However, the results also show that there is a general lack of understanding regarding the mechanism of carbon offsetting. Carbon offsetting providers in Japan and other countries that may have national self-imposed targets and allowing the usage of international carbon offsetting should therefore be considered, so as to provide individuals with the options of either contributing to their government to help it meet its national target or contributing to the world to help reduce GHG emissions beyond the national targets.

Guidance document to the BC emission offsets regulation

International Nuclear Information System (INIS)

2010-11-01

British Columbia's (BC) emission offset regulations were established under the Greenhouse Gas Reduction Targets Act passed in 2007. Targets for greenhouse gas (GHG) emission reductions included a 6 percent reduction by 2012; an 18 percent reduction by 2016; a 33 percent reduction by 2020; and an 80 percent reduction by 2050. Carbon neutral agreements began in 2008, and covered emissions produced from government business travel and by provincial government ministries and agencies. This report presented a list of key recommendations developed by the Pacific Carbon Trust for use in future carbon offset projects. Recommendations included the use of correct emission factors when quantifying projected emission reductions from an offset project; the use of a robust data management system; and the use of evidence in supporting additionality arguments. The document outlined planning procedures for project baseline selection processes, protocol selections, and the identification of sources sinks and reservoirs. Issues related to quantification and measurements, emissions factors, and accuracy and uncertainty were also addressed. Validation, verification, and contracting options were also presented. 6 tabs., 3 figs.

Multi-offset GPR methods for hyporheic zone investigations

Science.gov (United States)

Brosten, T.R.; Bradford, J.H.; McNamara, J.P.; Gooseff, M.N.; Zarnetske, J.P.; Bowden, W.B.; Johnston, M.E.

2009-01-01

Porosity of stream sediments has a direct effect on hyporheic exchange patterns and rates. Improved estimates of porosity heterogeneity will yield enhanced simulation of hyporheic exchange processes. Ground-penetrating radar (GPR) velocity measurements are strongly controlled by water content thus accurate measures of GPR velocity in saturated sediments provides estimates of porosity beneath stream channels using petrophysical relationships. Imaging the substream system using surface based reflection measurements is particularly challenging due to large velocity gradients that occur at the transition from open water to saturated sediments. The continuous multi-offset method improves the quality of subsurface images through stacking and provides measurements of vertical and lateral velocity distributions. We applied the continuous multi-offset method to stream sites on the North Slope, Alaska and the Sawtooth Mountains near Boise, Idaho, USA. From the continuous multi-offset data, we measure velocity using reflection tomography then estimate water content and porosity using the Topp equation. These values provide detailed measurements for improved stream channel hydraulic and thermal modelling. ?? 2009 European Association of Geoscientists & Engineers.

Joint compensation scheme of polarization crosstalk, intersymbol interference, frequency offset, and phase noise based on cascaded Kalman filter

Science.gov (United States)

Zhang, Qun; Yang, Yanfu; Xiang, Qian; Zhou, Zhongqing; Yao, Yong

2018-02-01

A joint compensation scheme based on cascaded Kalman filter is proposed, which can implement polarization tracking, channel equalization, frequency offset, and phase noise compensation simultaneously. The experimental results show that the proposed algorithm can not only compensate multiple channel impairments simultaneously but also improve the polarization tracking capacity and accelerate the convergence speed. The scheme has up to eight times faster convergence speed compared with radius-directed equalizer (RDE) + Max-FFT (maximum fast Fourier transform) + BPS (blind phase search) and can track up polarization rotation 60 times and 15 times faster than that of RDE + Max-FFT + BPS and CMMA (cascaded multimodulus algorithm) + Max-FFT + BPS, respectively.

Correlation between centre offsets and gas velocity dispersion of galaxy clusters in cosmological simulations

Science.gov (United States)

Li, Ming-Hua; Zhu, Weishan; Zhao, Dong

2018-05-01

The gas is the dominant component of baryonic matter in most galaxy groups and clusters. The spatial offsets of gas centre from the halo centre could be an indicator of the dynamical state of cluster. Knowledge of such offsets is important for estimate the uncertainties when using clusters as cosmological probes. In this paper, we study the centre offsets roff between the gas and that of all the matter within halo systems in ΛCDM cosmological hydrodynamic simulations. We focus on two kinds of centre offsets: one is the three-dimensional PB offsets between the gravitational potential minimum of the entire halo and the barycentre of the ICM, and the other is the two-dimensional PX offsets between the potential minimum of the halo and the iterative centroid of the projected synthetic X-ray emission of the halo. Haloes at higher redshifts tend to have larger values of rescaled offsets roff/r200 and larger gas velocity dispersion σ v^gas/σ _{200}. For both types of offsets, we find that the correlation between the rescaled centre offsets roff/r200 and the rescaled 3D gas velocity dispersion, σ _v^gas/σ _{200} can be approximately described by a quadratic function as r_{off}/r_{200} ∝ (σ v^gas/σ _{200} - k_2)2. A Bayesian analysis with MCMC method is employed to estimate the model parameters. Dependence of the correlation relation on redshifts and the gas mass fraction are also investigated.

Strain-free Ge/GeSiSn Quantum Cascade Lasers Based on L-Valley Intersubband Transitions

National Research Council Canada - National Science Library

Soret, R. A; Sun, G; Cheng, H; Menendez, J; Khurgin, J

2007-01-01

The authors propose a Ge/Ge0.76Si0.19Sn0.05 quantum cascade laser using intersubband transitions at L valleys of the conduction band which has a clean offset of 150 meV situated below other energy valleys Gamma and X...

Probing Photoinduced Structural Phase Transitions by Fast or Ultra-Fast Time-Resolved X-Ray Diffraction

Science.gov (United States)

Cailleau, Hervé Collet, Eric; Buron-Le Cointe, Marylise; Lemée-Cailleau, Marie-Hélène Koshihara, Shin-Ya

A new frontier in the field of structural science is the emergence of the fast and ultra-fast X-ray science. Recent developments in time-resolved X-ray diffraction promise direct access to the dynamics of electronic, atomic and molecular motions in condensed matter triggered by a pulsed laser irradiation, i.e. to record "molecular movies" during the transformation of matter initiated by light pulse. These laser pump and X-ray probe techniques now provide an outstanding opportunity for the direct observation of a photoinduced structural phase transition as it takes place. The use of X-ray short-pulse of about 100ps around third-generation synchrotron sources allows structural investigations of fast photoinduced processes. Other new X-ray sources, such as laser-produced plasma ones, generate ultra-short pulses down to 100 fs. This opens the way to femtosecond X-ray crystallography, but with rather low X-ray intensities and more limited experimental possibilities at present. However this new ultra-fast science rapidly progresses around these sources and new large-scale projects exist. It is the aim of this contribution to overview the state of art and the perspectives of fast and ultra-fast X-ray scattering techniques to study photoinduced phase transitions (here, the word ultra-fast is used for sub-picosecond time resolution). In particular we would like to largely present the contribution of crystallographic methods in comparison with optical methods, such as pump-probe reflectivity measurements, the reader being not necessary familiar with X-ray scattering. Thus we want to present which type of physical information can be obtained from the positions of the Bragg peaks, their intensity and their shape, as well as from the diffuse scattering beyond Bragg peaks. An important physical feature is to take into consideration the difference in nature between a photoinduced phase transition and conventional homogeneous photoinduced chemical or biochemical processes where

A Framework for Implementing and Valuing Biodiversity Offsets in Colombia: A Landscape Scale Perspective

Directory of Open Access Journals (Sweden)

Shirley Saenz

2013-11-01

Full Text Available Biodiversity offsets provide a mechanism for maintaining or enhancing environmental values in situations where development is sought, despite negative environmental impacts. They seek to ensure that unavoidable deleterious environmental impacts of development are balanced by environmental gains. When onsite impacts warrant the use of offsets there is often little attention paid to make sure that the location of offset sites provides the greatest conservation benefit, ensuring they are consistent with landscape level conservation goals. In most offset frameworks it is difficult for developers to proactively know the offset requirements they will need to implement. Here we propose a framework to address these needs. We propose a series of rules for selecting offset sites that meet the conservation needs of potentially impacted biological targets. We then discuss an accounting approach that seeks to support offset ratio determinations based on a structured and transparent approach. To demonstrate the approach, we present a framework developed in partnership with the Colombian Ministry of Environment and Sustainable Development to reform existing mitigation regulatory processes.

Fast antihydrogen beam spectroscopy

International Nuclear Information System (INIS)

Neumann, R.

1989-01-01

The motivation for production and precision spectroscopy of antihydrogen atoms is outlined. An experimental configuration is considered, concerning laser-microwave spectroscopy of a fast hydrogen beam with characteristics similar to those of an antihydrogen beam emanating from an antiproton-positron overlap region in an antiproton storage ring. In particular, a possible experiment for the measurement of the ground state hyperfine structure splitting is described. (orig.)

Non-dimensional scaling of impact fast ignition experiments

International Nuclear Information System (INIS)

Farley, D R; Shigemori, K; Murakami, M; Azechi, H

2008-01-01

Recent experiments at the Osaka University Institute for Laser Engineering (ILE) showed that 'Impact Fast Ignition' (IFI) could increase the neutron yield of inertial fusion targets by two orders of magnitude [1]. IFI utilizes the thermal and kinetic energy of a laser-accelerated disk to impact an imploded fusion target. ILE researchers estimate a disk velocity of 10 8 cm/sec is needed to ignite the fusion target [2]. To be able to study the IFI concept using lasers different from that at ILE, appropriate non-dimensionalization of the flow should be done. Analysis of the rocket equation gives parameters needed for producing similar IFI results with different lasers. This analysis shows that a variety of laboratory-scale commercial lasers could produce results useful to full-scale ILE experiments

Design of a Piezoelectric-Driven Tilt Mirror for a Fast Laser Scanner

Science.gov (United States)

Park, Jung-Ho; Lee, Hu-Seung; Lee, Jae-Hoon; Yun, So-Nam; Ham, Young-Bog; Yun, Dong-Won

2012-09-01

Recently, laser scanners have been used for laser processing such as cutting, welding, and grooving, especially in the automotive industry. The laser scanners need a high-speed driving to minimize cracks caused by thermal shock of brittle materials. Therefore, a novel laser processing system that is composed of a laser source and a piezoelectric-driven tilt mirror to control the reflection angle of the laser beam, and a stage equipped with the tilt mirror has been investigated. In this study, a piezoelectric-driven tilt mirror is designed and analyzed for scanning performance to achieve a beam spot of 30 µm, a pattern width of 1 mm, an overlap ratio of 70% of the circle area, and a scanning speed of 1 m/s. Then, structural analysis of the tilt mirror with three piezoelectric actuators is performed to determine the maximum reflection angle and resonance frequency. Finally, a prototype tilt mirror is fabricated and its basic characteristics are experimentally investigated and discussed.

Development of the laser alignment system with PSD used for shaft calibration

Science.gov (United States)

Jiao, Guohua; Li, Yulin; Hu, Baowen

2006-02-01

Shaft calibration is an important technique during installation and maintenance of a rotating machine. It requires unique and high-precision measurement instruments with calculation capability, and relies on experience on heavy, high-speed, or high-temperature machines. A high-precision laser alignment system has been designed using PSD (Position Sensing Detector) to change traditional manual way of shaft calibration and to make the measurement easier and more accurate. The system is comprised of two small measuring units (Laser transmitter and detector) and a hand operated control unit or a PC. Such a laser alignment system has been used in some actual shaft alignment with offset resolution 1.5μm and angular resolution 0.1°.

Laser speckle contrast imaging of skin blood perfusion responses induced by laser coagulation

Science.gov (United States)

Ogami, M.; Kulkarni, R.; Wang, H.; Reif, R.; Wang, R. K.

2014-08-01

We report application of laser speckle contrast imaging (LSCI), i.e., a fast imaging technique utilising backscattered light to distinguish such moving objects as red blood cells from such stationary objects as surrounding tissue, to localise skin injury. This imaging technique provides detailed information about the acute perfusion response after a blood vessel is occluded. In this study, a mouse ear model is used and pulsed laser coagulation serves as the method of occlusion. We have found that the downstream blood vessels lacked blood flow due to occlusion at the target site immediately after injury. Relative flow changes in nearby collaterals and anastomotic vessels have been approximated based on differences in intensity in the nearby collaterals and anastomoses. We have also estimated the density of the affected downstream vessels. Laser speckle contrast imaging is shown to be used for highresolution and fast-speed imaging for the skin microvasculature. It also allows direct visualisation of the blood perfusion response to injury, which may provide novel insights to the field of cutaneous wound healing.

Pair Cascades and Deathlines in Magnetic Fields with Offset Polar Caps

Science.gov (United States)

Harding, Alice K.; Muslimov, Alex G.

2012-01-01

We present results of electron-positron pair cascade simulations in a dipole magnetic field whose polar cap is offset from the dipole axis. In such a field geometry, the polar cap is displaced a small fraction of the neutron star radius from the star symmetry axis and the field line radius of curvature is modified. Using the modified parallel electric field near the offset polar cap, we simulate pair cascades to determine the pair deathlines and pair multiplicities as a function of the offset. We find that the pair multiplicity can change dr;unatically with a modest offset, with a significant increase on one side of the polar cap. Lower pair deathlines allow a larger fraction of the pulsar population, that include old and millisecond pulsars, to produce cascades with high multiplicity. The results have some important implications for pulsar particle production, high-energy emission and cosmic-ray contribution.

Scaling Trapped Ion Quantum Computers Using Fast Gates and Microtraps

Science.gov (United States)

Ratcliffe, Alexander K.; Taylor, Richard L.; Hope, Joseph J.; Carvalho, André R. R.

2018-06-01

Most attempts to produce a scalable quantum information processing platform based on ion traps have focused on the shuttling of ions in segmented traps. We show that an architecture based on an array of microtraps with fast gates will outperform architectures based on ion shuttling. This system requires higher power lasers but does not require the manipulation of potentials or shuttling of ions. This improves optical access, reduces the complexity of the trap, and reduces the number of conductive surfaces close to the ions. The use of fast gates also removes limitations on the gate time. Error rates of 10-5 are shown to be possible with 250 mW laser power and a trap separation of 100 μ m . The performance of the gates is shown to be robust to the limitations in the laser repetition rate and the presence of many ions in the trap array.

SU-E-J-259: Quantification of Rotational Localization Offset in Radiation Therapy

International Nuclear Information System (INIS)

Huang, Y; Nguyen, N; Lee, S; Liu, F

2014-01-01

Purpose: To verify the necessity of 6D localization detection and correction in radiation therapy. Methods: An anthropomorphic head and neck phantom was used to test the BrainLab ExacTrac x-ray imaging system. After initial positioning, both ExacTrac and the on-board kV CBCT were used to detect the offset at the same position, using both manual and automatic registration algorithms. Then 6D offset including rotational errors up to 5 degree were introduced. Both ExacTrac and CBCT were used to correct the offsets and the residual errors were evaluated. Finally, 6D offset detected by ExacTrac for a C-Spine patient was reported. Results: The differences in 3D offset detected by ExacTrac and CBCT were 1.5 ± 1.2(Lateral), 2.7 ± 2.7(Vertical), and 4.0 ± 6.3(longitudinal) mm with manual registration while the corresponding differences decreased to 0.6 ± 0.3, 1.0 ± 0.3, and 0.3 ± 0.3 when automatic registration were used. CBCT corrected the translational offset to within 0.5 mm but the rotational errors remained and detected by the ExacTrac system (Yaw=2.1, Roll=1.1, Pitch=1.4 degree). When similar offset was introduced and corrected using ExacTrac, the residual error detected by both CBCT and ExacTrac were within 0.5 mm / 0.5 degree. The average offset from the 112 ExacTrac x-ray corrections for the C-Spine patient was 0.6 ± 1.6 (lateral), 5.4 ± 8(vertical), 1.6±1.1(longitudinal) mm, and 0.7 ± 0.6 (pitch), 0.7 ± 0.4(roll), 1.2 ± 0.7 (yaw) degree. Larger rotational errors, with a maximum of 2.7 degree (corresponds to about 1.5 to 4.5 mm offset for a POI 10 to 30 cm away from the isocenter), were observed when couch rotational were involved. Conclusion: Rotational errors are common in patient localization, especially when couch rotation is involved. Both appropriate imaging system and 6D robotic couch are necessary to detect and correct the rotational localization errors

Forensic analysis of printing inks using tandem Laser Induced Breakdown Spectroscopy and Laser Ablation Inductively Coupled Plasma Mass Spectrometry

Science.gov (United States)

Subedi, Kiran; Trejos, Tatiana; Almirall, José

2015-01-01

Elemental analysis, using either LA-ICP-MS or LIBS, can be used for the chemical characterization of materials of forensic interest to discriminate between source materials originating from different sources and also for the association of materials known to originate from the same source. In this study, a tandem LIBS/LA-ICP-MS system that combines the benefits of both LIBS and LA-ICP-MS was evaluated for the characterization of samples of printing inks (toners, inkjets, intaglio and offset.). The performance of both laser sampling methods is presented. A subset of 9 black laser toners, 10 colored (CMYK) inkjet samples, 12 colored (CMYK) offset samples and 12 intaglio inks originating from different manufacturing sources were analyzed to evaluate the discrimination capability of the tandem method. These samples were selected because they presented a very similar elemental profile by LA-ICP-MS. Although typical discrimination between different ink sources is found to be > 99% for a variety of inks when only LA-ICP-MS was used for the analysis, additional discrimination was achieved by combining the elemental results from the LIBS analysis to the LA-ICP-MS analysis in the tandem technique, enhancing the overall discrimination capability of the individual laser ablation methods. The LIBS measurements of the Ca, Fe, K and Si signals, in particular, improved the discrimination for this specific set of different ink samples previously shown to exhibit very similar LA-ICP-MS elemental profiles. The combination of these two techniques in a single setup resulted in better discrimination of the printing inks with two distinct fingerprint spectra, providing information from atomic/ionic emissions and isotopic composition (m/z) for each ink sample.

Using Vision System Technologies for Offset Approaches in Low Visibility Operations

Science.gov (United States)

Kramer, Lynda J.; Bailey, Randall E.; Ellis, Kyle K.

2015-01-01

Flight deck-based vision systems, such as Synthetic Vision Systems (SVS) and Enhanced Flight Vision Systems (EFVS), have the potential to provide additional margins of safety for aircrew performance and enable the implementation of operational improvements for low visibility surface, arrival, and departure operations in the terminal environment with equivalent efficiency to visual operations. Twelve air transport-rated crews participated in a motion-base simulation experiment to evaluate the use of SVS/EFVS in Next Generation Air Transportation System low visibility approach and landing operations at Chicago O'Hare airport. Three monochromatic, collimated head-up display (HUD) concepts (conventional HUD, SVS HUD, and EFVS HUD) and three instrument approach types (straight-in, 3-degree offset, 15-degree offset) were experimentally varied to test the efficacy of the SVS/EFVS HUD concepts for offset approach operations. The findings suggest making offset approaches in low visibility conditions with an EFVS HUD or SVS HUD appear feasible. Regardless of offset approach angle or HUD concept being flown, all approaches had comparable ILS tracking during the instrument segment and were within the lateral confines of the runway with acceptable sink rates during the visual segment of the approach. Keywords: Enhanced Flight Vision Systems; Synthetic Vision Systems; Head-up Display; NextGen

In-Flight Calibration Methods for Temperature-Dependent Offsets in the MMS Fluxgate Magnetometers

Science.gov (United States)

Bromund, K. R.; Plaschke, F.; Strangeway, R. J.; Anderson, B. J.; Huang, B. G.; Magnes, W.; Fischer, D.; Nakamura, R.; Leinweber, H. K.; Russell, C. T.;

In-Flight Calibration Methods for Temperature-Dependendent Offsets in the MMS Fluxgate Magnetometers

Science.gov (United States)

Bromund, K. R.; Plaschke, F.; Strangeway, R. J.; Anderson, B. J.; Huang, B. G.; Magnes, W.; Fischer, D.; Nakamura, R.; Leinweber, H. K.; Russell, C. T.; Baumjohann, W.; Chutter, M.; Torbert, R. B.; Le, G.; Slavin, J. A.; Kepko, L.

2016-12-01

During the first dayside season of the Magnetospheric Multiscale (MMS) mission, the in-flight calibration process for the Fluxgate magnetometers (FGM) implemented an algorithm that selected a constant offset (zero-level) for each sensor on each orbit. This method was generally able to reduce the amplitude of residual spin tone to less than 0.2 nT within the region of interest. However, there are times when the offsets do show significant short-term variations. These variations are most prominent in the nighttime season (phase 1X), when eclipses are accompanied by offset changes as large as 1 nT. Eclipses are followed by a recovery period as long as 12 hours where the offsets continue to change as temperatures stabilize. Understanding and compensating for these changes will become critical during Phase 2 of the mission in 2017, when the nightside will become the focus of MMS science. Although there is no direct correlation between offset and temperature, the offsets are seen — for the period of any given week — to be well-characterized as function of instrument temperature. Using this property, a new calibration method has been developed that has proven effective in compensating for temperature-dependent offsets during phase 1X of the MMS mission and also promises to further refine calibration quality during the dayside season.

Correction of elevation offsets in multiple co-located lidar datasets

Science.gov (United States)

Thompson, David M.; Dalyander, P. Soupy; Long, Joseph W.; Plant, Nathaniel G.

2017-04-07

IntroductionTopographic elevation data collected with airborne light detection and ranging (lidar) can be used to analyze short- and long-term changes to beach and dune systems. Analysis of multiple lidar datasets at Dauphin Island, Alabama, revealed systematic, island-wide elevation differences on the order of 10s of centimeters (cm) that were not attributable to real-world change and, therefore, were likely to represent systematic sampling offsets. These offsets vary between the datasets, but appear spatially consistent within a given survey. This report describes a method that was developed to identify and correct offsets between lidar datasets collected over the same site at different times so that true elevation changes over time, associated with sediment accumulation or erosion, can be analyzed.

Laser Refractography

CERN Document Server

Rinkevichyus, B.S; Raskovskaya, I.L

2010-01-01

This book describes the basic principles of laser refractography, a flexible new diagnostic tool for measuring optically inhomogeneous media and flows. Laser refractography is based on digital imaging and computer processing of structured laser beam refraction (SLR) in inhomogeneous transparent media. Laser refractograms provide both qualitative and quantitative measurements and can be used for the study of fast and transient processes. In this book, the theoretical basis of refractography is explored in some detail, and experimental setups are described for measurement of transparent media using either 2D (passed radiation) or 3D (scattered radiation) refractograms. Specific examples and applications are discussed, including visualization of the boundary layer near a hot or cold metallic ball in water, and observation of edge effects and microlayers in liquids and gases. As the first book to describe this new and exciting technique, this monograph has broad cross-disciplinary appeal and will be of interest t...

CO2 laser interaction with magnetically confined plasmas. Annual report

International Nuclear Information System (INIS)

Vlases, G.C.; Pietrzyk, Z.A.

1977-08-01

The experimental program involves two basic experimental configurations termed the slow (or steady) solenoid, and the fast solenoid. In the former, the field is essentially steady during the experiment lifetime, the gas (plasma) remains in contact with the wall, and all the heating is done by the laser. In the fast solenoid, the field rises on a timescale comparable to the laser pulse length, removing the plasma from the wall, and contributing to the plasma energy content via compression work. In the slow solenoid, preionization is generally not used, and the laser both creates the plasma and heats it. In the fast solenoid, the preionization technique is relatively critical as it must create conditions leading to a true particle minimum on axis in order to insure favorable refraction of the laser beam (''trapping''). Substantial progress has been made in both experiments this year, particularly with respect to diagnostic capabilities. In addition, the theoretical effort has expanded considerably. Highlights of this year's program are listed and details are contained in the balance of the report

Using forest carbon credits to offset emissions in the downstream business

NARCIS (Netherlands)

Hein, Lars

2017-01-01

A forthcoming report by Concawe, entitled Using Forest Carbon Credits to Offset Emissions in the Downstream Business, investigated whether, and how, forest carbon credits can be used to offset emissions from the European refining and road transport sectors. Forest carbon plays a major role in the

Significant Improvements in Pyranometer Nighttime Offsets Using High-Flow DC Ventilation

Energy Technology Data Exchange (ETDEWEB)

Kutchenreiter, Mark; Michalski, J.J.; Long, C.N.; Habte, Aron

2017-05-22

Accurate solar radiation measurements using pyranometers are required to understand radiative impacts on the Earth's energy budget, solar energy production, and to validate radiative transfer models. Ventilators of pyranometers, which are used to keep the domes clean and dry, also affect instrument thermal offset accuracy. This poster presents a high-level overview of the ventilators for single-black-detector pyranometers and black-and-white pyranometers. For single-black-detector pyranometers with ventilators, high-flow-rate (50-CFM and higher), 12-V DC fans lower the offsets, lower the scatter, and improve the predictability of nighttime offsets compared to lower-flow-rate (35-CFM), 120-V AC fans operated in the same type of environmental setup. Black-and-white pyranometers, which are used to measure diffuse horizontal irradiance, sometimes show minor improvement with DC fan ventilation, but their offsets are always small, usually no more than 1 W/m2, whether AC- or DC-ventilated.

Effects of laser wavelength and density scale length on absorption of ultrashort intense lasers on solid-density targets

Energy Technology Data Exchange (ETDEWEB)

Susumu, Kato; Eiichi, Takahashi; Tatsuya, Aota; Yuji, Matsumoto; Isao, Okuda; Yoshiro, Owadano [National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki (Japan)

2004-07-01

The interaction of intense laser pulses with overdense plasmas has attracted much interest for the fast igniter concept in inertial fusion energy. Hot electron temperatures and electron energy spectra in the course of interaction between intense laser pulse and overdense plasmas are reexamined from a viewpoint of the difference in laser wavelength. The hot electron temperature measured by a particle-in-cell simulation is scaled by I rather than I{lambda}{sup 2} at the interaction with overdense plasmas with fixed ions, where I and {lambda} are the laser intensity and wavelength, respectively. (authors)

Echoic Memory: Investigation of Its Temporal Resolution by Auditory Offset Cortical Responses

OpenAIRE

Nishihara, Makoto; Inui, Koji; Morita, Tomoyo; Kodaira, Minori; Mochizuki, Hideki; Otsuru, Naofumi; Motomura, Eishi; Ushida, Takahiro; Kakigi, Ryusuke

2014-01-01

Previous studies showed that the amplitude and latency of the auditory offset cortical response depended on the history of the sound, which implicated the involvement of echoic memory in shaping a response. When a brief sound was repeated, the latency of the offset response depended precisely on the frequency of the repeat, indicating that the brain recognized the timing of the offset by using information on the repeat frequency stored in memory. In the present study, we investigated the temp...

Fast-shock ignition: a new approach to inertial confinement fusion

Directory of Open Access Journals (Sweden)

AH Farahbod

2013-03-01

Full Text Available  A new concept for inertial confinement fusion called fast-shock ignition (FSI is introduced as a credible scheme in order to obtain high target gain. In the proposed model, the separation of fuel ignition into two successive steps, under the suitable conditions, reduces required ignitor energy for the fuel ignition. The main procedure in FSI concept is compressing the fuel up to stagnation. Then, two high intensity short pulse laser spikes with energy and power lower than those required for shock ignition (SI and fast ignition (FI with a proper delay time are launched at the fuel which increases the central hot-spot temperature and completes the ignition of the precompressed fuel. The introduced semi-analytical model indicates that with fast-shock ignition, the total required energy for compressing and igniting the fuel can be slightly reduced in comparison to pure shock ignition. Furthermore, for fuel mass greater than , the target energy gain increases up to 15 percent and the contribution of fast ignitor under the proper conditions could be decreased about 20 percent compared with pure fast ignition. The FSI scheme is beneficial from technological considerations for the construction of short pulse high power laser drivers. The general advantages of fast-shock ignition over pure shock ignition in terms of figure of merit can be more than 1.3.

45 CFR 2506.33 - How will the Corporation coordinate salary offsets with other agencies?

Science.gov (United States)

2010-10-01

... 45 Public Welfare 4 2010-10-01 2010-10-01 false How will the Corporation coordinate salary offsets... (Continued) CORPORATION FOR NATIONAL AND COMMUNITY SERVICE COLLECTION OF DEBTS Salary Offset § 2506.33 How will the Corporation coordinate salary offsets with other agencies? (a) Responsibilities of the...

Band Offsets at the Interface between Crystalline and Amorphous Silicon from First Principles

Science.gov (United States)

Jarolimek, K.; Hazrati, E.; de Groot, R. A.; de Wijs, G. A.

2017-07-01

The band offsets between crystalline and hydrogenated amorphous silicon (a -Si ∶H ) are key parameters governing the charge transport in modern silicon heterojunction solar cells. They are an important input for macroscopic simulators that are used to further optimize the solar cell. Past experimental studies, using x-ray photoelectron spectroscopy (XPS) and capacitance-voltage measurements, have yielded conflicting results on the band offset. Here, we present a computational study on the band offsets. It is based on atomistic models and density-functional theory (DFT). The amorphous part of the interface is obtained by relatively long DFT first-principles molecular-dynamics runs at an elevated temperature on 30 statistically independent samples. In order to obtain a realistic conduction-band position the electronic structure of the interface is calculated with a hybrid functional. We find a slight asymmetry in the band offsets, where the offset in the valence band (0.29 eV) is larger than in the conduction band (0.17 eV). Our results are in agreement with the latest XPS measurements that report a valence-band offset of 0.3 eV [M. Liebhaber et al., Appl. Phys. Lett. 106, 031601 (2015), 10.1063/1.4906195].

Experimental demonstration of a compact epithermal neutron source based on a high power laser

Science.gov (United States)

Mirfayzi, S. R.; Alejo, A.; Ahmed, H.; Raspino, D.; Ansell, S.; Wilson, L. A.; Armstrong, C.; Butler, N. M. H.; Clarke, R. J.; Higginson, A.; Kelleher, J.; Murphy, C. D.; Notley, M.; Rusby, D. R.; Schooneveld, E.; Borghesi, M.; McKenna, P.; Rhodes, N. J.; Neely, D.; Brenner, C. M.; Kar, S.

2017-07-01

Epithermal neutrons from pulsed-spallation sources have revolutionised neutron science allowing scientists to acquire new insight into the structure and properties of matter. Here, we demonstrate that laser driven fast (˜MeV) neutrons can be efficiently moderated to epithermal energies with intrinsically short burst durations. In a proof-of-principle experiment using a 100 TW laser, a significant epithermal neutron flux of the order of 105 n/sr/pulse in the energy range of 0.5-300 eV was measured, produced by a compact moderator deployed downstream of the laser-driven fast neutron source. The moderator used in the campaign was specifically designed, by the help of MCNPX simulations, for an efficient and directional moderation of the fast neutron spectrum produced by a laser driven source.

20 CFR 361.13 - Procedures for salary offset: Methods of collection.

Science.gov (United States)

2010-04-01

... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false Procedures for salary offset: Methods of collection. 361.13 Section 361.13 Employees' Benefits RAILROAD RETIREMENT BOARD INTERNAL ADMINISTRATION... § 361.13 Procedures for salary offset: Methods of collection. (a) General. A debt will be collected by...

7 CFR 400.138 - Procedures for salary offset; methods of collection.

Science.gov (United States)

2010-01-01

... 7 Agriculture 6 2010-01-01 2010-01-01 false Procedures for salary offset; methods of collection. 400.138 Section 400.138 Agriculture Regulations of the Department of Agriculture (Continued) FEDERAL... Management-Regulations for the 1986 and Succeeding Crop Years § 400.138 Procedures for salary offset; methods...

Ultra-fast laser microprocessing of medical polymers for cell engineering applications

International Nuclear Information System (INIS)

Ortiz, R.; Moreno-Flores, S.; Quintana, I.; Vivanco, MdM; Sarasua, J.R.; Toca-Herrera, J.L.

2014-01-01

Picosecond laser micromachining technology (PLM) has been employed as a tool for the fabrication of 3D structured substrates. These substrates have been used as supports in the in vitro study of the effect of substrate topography on cell behavior. Different micropatterns were PLM-generated on polystyrene (PS) and poly-L-lactide (PLLA) and employed to study cellular proliferation and morphology of breast cancer cells. The laser-induced microstructures included parallel lines of comparable width to that of a single cell (which in this case is roughly 20 μm), and the fabrication of square-like compartments of a much larger area than a single cell (250,000 μm 2 ). The results obtained from this in vitro study showed that though the laser treatment altered substrate roughness, it did not noticeably affect the adhesion and proliferation of the breast cancer cells. However, pattern direction directly affected cell proliferation, leading to a guided growth of cell clusters along the pattern direction. When cultured in square-like compartments, cells remained confined inside these for eleven incubation days. According to these results, laser micromachining with ultra-short laser pulses is a suitable method to directly modify the cell microenvironment in order to induce a predefined cellular behavior and to study the effect of the physical microenvironment on cell proliferation. - Highlights: • Microstructuring of biocompatible polymers by ultra-short pulsed laser technology. • Contact guidance effect on a supracellular scale along microgrooved substrates. • Cell confinement inside square compartments. • Fabrication of a 3D microenvironment that induces predefined behavior of cells

Ultra-fast laser microprocessing of medical polymers for cell engineering applications

Energy Technology Data Exchange (ETDEWEB)

Ortiz, R. [Ultraprecision Processes Unit, Fundación IK4-TEKNIKER, Iñaki Goenaga 5, 20600, Eibar, Gipuzkoa (Spain); Moreno-Flores, S., E-mail: susana.moreno-flores@boku.ac.at [Biosurfaces Unit, CIC biomaGUNE, Po Miramón, 182, 20009, San Sebastián, Donostia (Spain); Quintana, I., E-mail: iban.quintana@tekniker.es [Ultraprecision Processes Unit, Fundación IK4-TEKNIKER, Iñaki Goenaga 5, 20600, Eibar, Gipuzkoa (Spain); Micro and Nanoengineering Unit, CIC microGUNE, Goiru Kalea 9, 20500, Arrasate-Mondragón, Gipuzkoa (Spain); Vivanco, MdM [Cell Biology and Stem Cells Unit, CIC bioGUNE, Technology Park of Bizkaia, Ed. 801A, 48160 Derio (Spain); Sarasua, J.R. [University of the Basque Country (EHU-UPV), School of Engineering, Department of Mining and Metallurgy Engineering and Materials Science, Alameda de Urquijo s/n, 48013 Bilbao (Spain); Toca-Herrera, J.L. [Biosurfaces Unit, CIC biomaGUNE, Po Miramón, 182, 20009, San Sebastián, Donostia (Spain); Micro and Nanoengineering Unit, CIC microGUNE, Goiru Kalea 9, 20500, Arrasate-Mondragón, Gipuzkoa (Spain)

2014-04-01

Picosecond laser micromachining technology (PLM) has been employed as a tool for the fabrication of 3D structured substrates. These substrates have been used as supports in the in vitro study of the effect of substrate topography on cell behavior. Different micropatterns were PLM-generated on polystyrene (PS) and poly-L-lactide (PLLA) and employed to study cellular proliferation and morphology of breast cancer cells. The laser-induced microstructures included parallel lines of comparable width to that of a single cell (which in this case is roughly 20 μm), and the fabrication of square-like compartments of a much larger area than a single cell (250,000 μm{sup 2}). The results obtained from this in vitro study showed that though the laser treatment altered substrate roughness, it did not noticeably affect the adhesion and proliferation of the breast cancer cells. However, pattern direction directly affected cell proliferation, leading to a guided growth of cell clusters along the pattern direction. When cultured in square-like compartments, cells remained confined inside these for eleven incubation days. According to these results, laser micromachining with ultra-short laser pulses is a suitable method to directly modify the cell microenvironment in order to induce a predefined cellular behavior and to study the effect of the physical microenvironment on cell proliferation. - Highlights: • Microstructuring of biocompatible polymers by ultra-short pulsed laser technology. • Contact guidance effect on a supracellular scale along microgrooved substrates. • Cell confinement inside square compartments. • Fabrication of a 3D microenvironment that induces predefined behavior of cells.

Plasma ion emission from high intensity picosecond laser pulse interactions with solid targets

International Nuclear Information System (INIS)

Fews, A.P.; Norreys, P.A.; Beg, F.N.; Bell, A.R.; Dangor, A.E.; Danson, C.N.; Lee, P.; Rose, S.J.

1994-01-01

The fast ion emission from high intensity, picosecond laser plasmas has been measured to give the characteristic ion energy and the amount of laser energy transferred to ions with energies ≥100 keV/nucleon as a function of incident intensity. The characteristic ion energy varies from 0.2 to 1.3 MeV over the range 2.0x10 17 --2.0x10 18 W cm -2 . Ten percent of the laser energy is transferred into MeV ions at 2.0x10 18 W cm -2 . Calculations of stopping power in high density materials are presented that show that fast ions cannot be ignored in modeling fast ignitor schemes

Band offsets in ITO/Ga2O3 heterostructures

Science.gov (United States)

Carey, Patrick H.; Ren, F.; Hays, David C.; Gila, B. P.; Pearton, S. J.; Jang, Soohwan; Kuramata, Akito

2017-11-01

The valence band offsets in rf-sputtered Indium Tin Oxide (ITO)/single crystal β-Ga2O3 (ITO/Ga2O3) heterostructures were measured with X-Ray Photoelectron Spectroscopy using the Kraut method. The bandgaps of the component materials in the heterostructure were determined by Reflection Electron Energy Loss Spectroscopy as 4.6 eV for Ga2O3 and 3.5 eV for ITO. The valence band offset was determined to be -0.78 ± 0.30 eV, while the conduction band offset was determined to be -0.32 ± 0.13 eV. The ITO/Ga2O3 system has a nested gap (type I) alignment. The use of a thin layer of ITO between a metal and the Ga2O3 is an attractive approach for reducing contact resistance on Ga2O3-based power electronic devices and solar-blind photodetectors.

38 CFR 1.990 - Written agreement to repay debt as alternative to salary offset.

Science.gov (United States)

2010-07-01

... repay debt as alternative to salary offset. 1.990 Section 1.990 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS GENERAL PROVISIONS Salary Offset Provisions § 1.990 Written agreement to repay debt as alternative to salary offset. (a) Notification by employee. The employee may propose, in...

Kerr-lens mode-locked Ti:Sapphire laser pumped by a single laser diode

Science.gov (United States)

Kopylov, D. A.; Esaulkov, M. N.; Kuritsyn, I. I.; Mavritskiy, A. O.; Perminov, B. E.; Konyashchenko, A. V.; Murzina, T. V.; Maydykovskiy, A. I.

2018-04-01

The performance of a Ti:sapphire laser pumped by a single 461 nm laser diode is presented for both the continuous-wave and the mode-locked regimes of operation. We introduce a simple astigmatism correction scheme for the laser diode beam consisting of two cylindrical lenses affecting the pump beam along the fast axis of the laser diode, which provides the mode-matching between the nearly square-shaped pump beam and the cavity mode. The resulting efficiency of the suggested Ti:Sapphire oscillator pumped by such a laser diode is analyzed for the Ti:sapphire crystals of 3 mm, 5 mm and 10 mm in length. We demonstrate that such a system provides the generation of ultrashort pulses up to 15 fs in duration with the repetition rate of 87 MHz, the average power being 170 mW.

Digital Offset Calibration of an OPAMP Towards Improving Static Parameters of 90 nm CMOS DAC

Directory of Open Access Journals (Sweden)

D. Arbet

2014-09-01

Full Text Available In this paper, an on-chip self-calibrated 8-bit R-2R digital-to-analog converter (DAC based on digitally compensated input offset of the operational amplifier (OPAMP is presented. To improve the overall DAC performance, a digital offset cancellation method was used to compensate deviations in the input offset voltage of the OPAMP caused by process variations. The whole DAC as well as offset compensation circuitry were designed in a standard 90 nm CMOS process. The achieved results show that after the self-calibration process, the improvement of 48% in the value of DAC offset error is achieved.

Topographic Correction of GPR Profiles Based on Laser Data

International Nuclear Information System (INIS)

Zhang, Di; Zhong, Ruofei; Li, Jia Cun; Zeng, Fanyang

2014-01-01

Data obtained by GPR (Ground Penetrating Radar) are displayed as a continuous cross-sectional profile. Surface, generally, is not flat. As a result, the image becomes distorted and the depth calculated from the surface no longer represents the true and exact position of electrically distinctive layers and objects in materials. In order to get real geologic cross section, GPR data must be corrected. This is paper discusses a new method using the color point cloud data obtained by a Vehicle-borne laser scanning system to compensate for elevation fluctuate. Elevation profile can be extracted from topographic data of survey site acquired using laser scanner, which can then be used to offset the error of GPR data. Through the discrete points in the survey line, each trace of the profile has its own elevation value showing a vertical difference from the reference profile with maximum elevation, then time shifts value of traces vertical offset versus the reference trace of profile can be obtained. At last, the results of topographic correction for radargrams that look extremely like the real geologic cross section are presented, which allows us to get a better profile interpretation and position of the objects and layers in the subsurface

Dependence of Parameters of Laser-Produced Au Plasmas on the Incident Laser Energy of Sub-Nanosecond and Picosecond Laser Pulses

International Nuclear Information System (INIS)

Woryna, E.; Badziak, J.; Makowski, J.; Parys, P.; Vankov, A.B.; Wolowski, J.; Krasa, J.; Laska, L.; Rohlena, K.

2001-01-01

The parameters of Au plasma as functions of laser energy for ps pulses are presented and compared with the ones for sub-ns pulses at nearly the same densities of laser energy. The experiments were performed at the IPPLM with the use of CPA (chirped pulse amplification) Nd:glass laser system. Thick Au foil targets were irradiated by normally incident focused laser beams with maximum intensities of 8x10 16 and 2x10 14 W/cm 2 for ps and sub-ns laser pulses, respectively. The characteristics of ion streams were investigated with the use of ion diagnostics methods based on the time-of flight technique. In these experiments the laser energies were changed in the range from 90 to 700 mJ and the measurements were performed at a given focus position FP = 0 and along the target normal for both the laser pulses. The charge carried by the ions, the maximum ion velocities of fast and thermal ion groups, the maximum ion current density as well as the area of photopeak in dependence on the incident laser energy for sub-ns and ps pulses were investigated and discussed. (author)

Temperature and Voltage Offsets in High-ZT Thermoelectrics

Science.gov (United States)

Levy, George S.

2017-10-01

Thermodynamic temperature can take on different meanings. Kinetic temperature is an expectation value and a function of the kinetic energy distribution. Statistical temperature is a parameter of the distribution. Kinetic temperature and statistical temperature, identical in Maxwell-Boltzmann statistics, can differ in other statistics such as those of Fermi-Dirac or Bose-Einstein when a field is present. Thermal equilibrium corresponds to zero statistical temperature gradient, not zero kinetic temperature gradient. Since heat carriers in thermoelectrics are fermions, the difference between these two temperatures may explain voltage and temperature offsets observed during meticulous Seebeck measurements in which the temperature-voltage curve does not go through the origin. In conventional semiconductors, temperature offsets produced by fermionic electrical carriers are not observable because they are shorted by heat phonons in the lattice. In high-ZT materials, however, these offsets have been detected but attributed to faulty laboratory procedures. Additional supporting evidence for spontaneous voltages and temperature gradients includes data collected in epistatic experiments and in the plasma Q-machine. Device fabrication guidelines for testing the hypothesis are suggested including using unipolar junctions stacked in a superlattice, alternating n/n + and p/p + junctions, selecting appropriate dimensions, doping, and loading.

Temperature and Voltage Offsets in High- ZT Thermoelectrics

Science.gov (United States)

Levy, George S.

2018-06-01

Thermodynamic temperature can take on different meanings. Kinetic temperature is an expectation value and a function of the kinetic energy distribution. Statistical temperature is a parameter of the distribution. Kinetic temperature and statistical temperature, identical in Maxwell-Boltzmann statistics, can differ in other statistics such as those of Fermi-Dirac or Bose-Einstein when a field is present. Thermal equilibrium corresponds to zero statistical temperature gradient, not zero kinetic temperature gradient. Since heat carriers in thermoelectrics are fermions, the difference between these two temperatures may explain voltage and temperature offsets observed during meticulous Seebeck measurements in which the temperature-voltage curve does not go through the origin. In conventional semiconductors, temperature offsets produced by fermionic electrical carriers are not observable because they are shorted by heat phonons in the lattice. In high- ZT materials, however, these offsets have been detected but attributed to faulty laboratory procedures. Additional supporting evidence for spontaneous voltages and temperature gradients includes data collected in epistatic experiments and in the plasma Q-machine. Device fabrication guidelines for testing the hypothesis are suggested including using unipolar junctions stacked in a superlattice, alternating n/ n + and p/ p + junctions, selecting appropriate dimensions, doping, and loading.

20 CFR 361.12 - Procedures for salary offset: Types of collection.

Science.gov (United States)

2010-04-01

... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false Procedures for salary offset: Types of collection. 361.12 Section 361.12 Employees' Benefits RAILROAD RETIREMENT BOARD INTERNAL ADMINISTRATION... § 361.12 Procedures for salary offset: Types of collection. A debt will be collected in a lump sum or in...

7 CFR 400.137 - Procedures for salary offset; types of collection.

Science.gov (United States)

2010-01-01

... 7 Agriculture 6 2010-01-01 2010-01-01 false Procedures for salary offset; types of collection. 400.137 Section 400.137 Agriculture Regulations of the Department of Agriculture (Continued) FEDERAL CROP...-Regulations for the 1986 and Succeeding Crop Years § 400.137 Procedures for salary offset; types of collection...

An Examination of Tailored Training Offsets on Core Mortarman Skills Acquisition

Science.gov (United States)

2016-02-01

Training, Mortar, Mortar Gunner’s Exam , Tests SECURITY CLASSIFICATION OF 19. LIMITATION OF ABSTRACT 20...training offsets in 11C OSUT, and ( c ) provide guidance and tools for developing effective training offsets to enhance Soldiers’ core skills proficiencies...Two-Week Mortar Training Including Gunner’s Exam ............................... 13 Knowledge and Application Tests

Precise Range Determination Using Laser Ranging Data of LAGEOS

Directory of Open Access Journals (Sweden)

Kwang-Ryul Kim

1993-12-01

Full Text Available Satellite laser ranging observation of LAGEOS ¥± has been performed using the SLR System at Sheshan Laser Ranging Station, Shanghai Observatory. And we obtained 1,838 observational points The observed range data is corrected by means of system delay correction using ground target observation, atmospheric refraction delay correction, offset correction, general relativistic correction and tide correction including solid tide, polar tide and ocean tide. As a result, the determined range delay mean value is 19.12m and the mean internal accuracy by means of polynomial fitting and least square method is ¡¾7cm. Corrected observational points are 1,340 and noise ratio to total observational points is 27.1%

24 CFR 17.133 - Written agreement to repay debt as alternative to salary offset.

Science.gov (United States)

2010-04-01

... alternative to salary offset. 17.133 Section 17.133 Housing and Urban Development Office of the Secretary... the Government Salary Offset Provisions § 17.133 Written agreement to repay debt as alternative to salary offset. (a) Notification by employee. The employee may propose, in response to a Notice of Intent...

20 CFR 361.10 - Written agreement to repay debt as alternative to salary offset.

Science.gov (United States)

2010-04-01

... alternative to salary offset. 361.10 Section 361.10 Employees' Benefits RAILROAD RETIREMENT BOARD INTERNAL... EMPLOYEES § 361.10 Written agreement to repay debt as alternative to salary offset. (a) Notification by... debt as an alternative to salary offset. Any employee who wishes to do this must submit a proposed...

Accounting for Uncertainty and Time Lags in Equivalency Calculations for Offsetting in Aquatic Resources Management Programs.

Science.gov (United States)

Bradford, Michael J

2017-10-01

Biodiversity offset programs attempt to minimize unavoidable environmental impacts of anthropogenic activities by requiring offsetting measures in sufficient quantity to counterbalance losses due to the activity. Multipliers, or offsetting ratios, have been used to increase the amount of offsets to account for uncertainty but those ratios have generally been derived from theoretical or ad-hoc considerations. I analyzed uncertainty in the offsetting process in the context of offsetting for impacts to freshwater fisheries productivity. For aquatic habitats I demonstrate that an empirical risk-based approach for evaluating prediction uncertainty is feasible, and if data are available appropriate adjustments to offset requirements can be estimated. For two data-rich examples I estimate multipliers in the range of 1.5:1 - 2.5:1 are sufficient to account for the uncertainty in the prediction of gains and losses. For aquatic habitats adjustments for time delays in the delivery of offset benefits can also be calculated and are likely smaller than those for prediction uncertainty. However, the success of a biodiversity offsetting program will also depend on the management of the other components of risk not addressed by these adjustments.

Accounting for Uncertainty and Time Lags in Equivalency Calculations for Offsetting in Aquatic Resources Management Programs

Science.gov (United States)

Bradford, Michael J.

2017-10-01

Biodiversity offset programs attempt to minimize unavoidable environmental impacts of anthropogenic activities by requiring offsetting measures in sufficient quantity to counterbalance losses due to the activity. Multipliers, or offsetting ratios, have been used to increase the amount of offsets to account for uncertainty but those ratios have generally been derived from theoretical or ad-hoc considerations. I analyzed uncertainty in the offsetting process in the context of offsetting for impacts to freshwater fisheries productivity. For aquatic habitats I demonstrate that an empirical risk-based approach for evaluating prediction uncertainty is feasible, and if data are available appropriate adjustments to offset requirements can be estimated. For two data-rich examples I estimate multipliers in the range of 1.5:1 - 2.5:1 are sufficient to account for the uncertainty in the prediction of gains and losses. For aquatic habitats adjustments for time delays in the delivery of offset benefits can also be calculated and are likely smaller than those for prediction uncertainty. However, the success of a biodiversity offsetting program will also depend on the management of the other components of risk not addressed by these adjustments.

Automatic WEMVA by Focusing Subsurface Offset Virtual Sources

KAUST Repository

Sun, Bingbing

2017-05-26

Macro velocity building is important for subsequent prestack depth migration and full waveform inversion. Wave equation migration velocity analysis (WEMVA) utilizes band-limited waveform to invert the velocity in an automatic manner. Normally, inversion would be implemented by focusing the subsurface offset common image gathers(SOCIGs). We re-examine it with a different perspective and propose to view the SOCIGs and the background wavefield together as subsurface offset virtual sources(SOVS). A linear system connecting the perturbation of the position of those SOVS and velocity is derived and solved subsequently using a conjugate gradient method. Both synthetic and real dataset examples verify the correctness and effectiveness of the proposed method.

Experimental study of hot electrons propagation and energy deposition in solid or laser-shock compressed targets: applications to fast igniter; Etude experimentale de la propagation et du depot d'energie d'electrons rapides dans une cible solide ou comprimee par choc laser: application a l'allumeur rapide

Energy Technology Data Exchange (ETDEWEB)

Pisani, F

2000-02-15

In the fast igniter scheme, a recent approach proposed for the inertial confinement fusion, the idea is to dissociate the fuel ignition phase from its compression. The ignition phase would be then achieved by means of an external energy source: a fast electron beam generated by the interaction with an ultra-intense laser. The main goal of this work is to study the mechanisms of the hot electron energy transfer to the compressed fuel. We intent in particular to study the role of the electric and collisional effects involved in the hot electron propagation in a medium with properties similar to the compressed fuel. We carried out two experiments, one at the Vulcan laser facility (England) and the second one at the new LULI 100 TW laser (France). During the first experiment, we obtained the first results on the hot electron propagation in a dense and hot plasma. The innovating aspect of this work was in particular the use of the laser-shock technique to generate high pressures, allowing the strongly correlated and degenerated plasma to be created. The role of the electric and magnetic effects due to the space charge associated with the fast electron beam has been investigated in the second experiment. Here we studied the propagation in materials with different electrical characteristics: an insulator and a conductor. The analysis of the results showed that only by taking into account simultaneously the two propagation mechanisms (collisions and electric effects) a correct treatment of the energy deposition is possible. We also showed the importance of taking into account the induced modifications due to the electrons beam crossing the target, especially the induced heating. (author)

20 CFR 627.708 - Offset process.

Science.gov (United States)

2010-04-01

... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Offset process. 627.708 Section 627.708 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR GENERAL PROVISIONS GOVERNING... process. (a) In accordance with section 164(d) of the Act, the primary sanction for misexpenditure of JTPA...

The potential for biodiversity offsetting to fund effective invasive species control.

Science.gov (United States)

Norton, David A; Warburton, Bruce

2015-02-01

Compensating for biodiversity losses in 1 location by conserving or restoring biodiversity elsewhere (i.e., biodiversity offsetting) is being used increasingly to compensate for biodiversity losses resulting from development. We considered whether a form of biodiversity offsetting, enhancement offsetting (i.e., enhancing the quality of degraded natural habitats through intensive ecological management), can realistically secure additional funding to control biological invaders at a scale and duration that results in enhanced biodiversity outcomes. We suggest that biodiversity offsetting has the potential to enhance biodiversity values through funding of invasive species control, but it needs to meet 7 key conditions: be technically possible to reduce invasive species to levels that enhance native biodiversity; be affordable; be sufficiently large to compensate for the impact; be adaptable to accommodate new strategic and tactical developments while not compromising biodiversity outcomes; acknowledge uncertainties associated with managing pests; be based on an explicit risk assessment that identifies the cost of not achieving target outcomes; and include financial mechanisms to provide for in-perpetuity funding. The challenge then for conservation practitioners, advocates, and policy makers is to develop frameworks that allow for durable and effective partnerships with developers to realize the full potential of enhancement offsets, which will require a shift away from traditional preservation-focused approaches to biodiversity management. © 2014 Society for Conservation Biology.

High accuracy 3-D laser radar

DEFF Research Database (Denmark)

Busck, Jens; Heiselberg, Henning

2004-01-01

We have developed a mono-static staring 3-D laser radar based on gated viewing with range accuracy below 1 m at 10 m and 1 cm at 100. We use a high sensitivity, fast, intensified CCD camera, and a Nd:Yag passively Q-switched 32.4 kHz pulsed green laser at 532 nm. The CCD has 752x582 pixels. Camera...

Atomic motion in a high-intensity standing wave laser field

International Nuclear Information System (INIS)

Saez Ramdohr, L.F.

1987-01-01

This work discusses the effect of a high-intensity standing wave laser field on the motion of neutral atoms moving with a relatively high velocity. The analysis involves a detailed calculation of the force acting on the atoms and the calculation of the diffusion tensor associated with the fluctuations of the quantum force operator. The high-intensity laser field limit corresponds to a Rabi frequency much greater than the natural rate of the atom. The general results are valid for any atomic velocity. Results are then specialized to the case of slow and fast atoms where the Doppler shift of the laser frequency due to the atomic motion is either smaller or larger than the natural decay rate of the atom. The results obtained for the force and diffusion tensor are applied to a particular ideal experiment that studies the evolution of a fast atomic beam crossing a high-intensity laser beam. The theories developed previously, for a similar laser configuration, discuss only the low atomic velocities case and not the more realistic case of fast atoms. Here, an approximate solution of the equation for the distribution is obtained. Starting from the approximate distribution function, the deflection angle and dispersion angle for the atomic beam with respect to the free motion are calculated

Device for frequency modulation of a laser output spectrum

Science.gov (United States)

Beene, J.R.; Bemis, C.E. Jr.

1984-07-17

A device is provided for fast frequency modulating the output spectrum of multimode lasers and single frequency lasers that are not actively stabilized. A piezoelectric transducer attached to a laser cavity mirror is driven in an unconventional manner to excite resonance vibration of the tranducer to rapidly, cyclicly change the laser cavity length. The result is a cyclic sweeping of the output wavelength sufficient to fill the gaps in the laser output frequency spectrum. When a laser is used to excite atoms or molecules, complete absorption line coverage is made possible.

Through tissue imaging of a live breast cancer tumour model using handheld surface enhanced spatially offset resonance Raman spectroscopy (SESORRS).

Science.gov (United States)

Nicolson, Fay; Jamieson, Lauren E; Mabbott, Samuel; Plakas, Konstantinos; Shand, Neil C; Detty, Michael R; Graham, Duncan; Faulds, Karen

2018-04-21

In order to improve patient survival and reduce the amount of unnecessary and traumatic biopsies, non-invasive detection of cancerous tumours is of imperative and urgent need. Multicellular tumour spheroids (MTS) can be used as an ex vivo cancer tumour model, to model in vivo nanoparticle (NP) uptake by the enhanced permeability and retention (EPR) effect. Surface enhanced spatially offset Raman spectroscopy (SESORS) combines both surface enhanced Raman spectroscopy (SERS) and spatially offset Raman spectroscopy (SORS) to yield enhanced Raman signals at much greater sub-surface levels. By utilizing a reporter that has an electronic transition in resonance with the laser frequency, surface enhanced resonance Raman scattering (SERRS) yields even greater enhancement in Raman signal. Using a handheld SORS spectrometer with back scattering optics, we demonstrate the detection of live breast cancer 3D MTS containing SERRS active NPs through 15 mm of porcine tissue. False color 2D heat intensity maps were used to determine tumour model location. In addition, we demonstrate the tracking of SERRS-active NPs through porcine tissue to depths of up to 25 mm. This unprecedented performance is due to the use of red-shifted chalcogenpyrylium-based Raman reporters to demonstrate the novel technique of surface enhanced spatially offset resonance Raman spectroscopy (SESORRS) for the first time. Our results demonstrate a significant step forward in the ability to detect vibrational fingerprints from a tumour model at depth through tissue. Such an approach offers significant promise for the translation of NPs into clinical applications for non-invasive disease diagnostics based on this new chemical principle of measurement.

Features of a point design for Fast Ignition

International Nuclear Information System (INIS)

Tabak, M; Clark, D; Town, R P J; Key, M H; Amendt, P; Ho, D; Meeker, D J; Shay, H D; Lasinski, B F; Kemp, A; Divol, L; Mackinnon, A J; Patel, P; Strozzi, D; Grote, D P

2010-01-01

Fast Ignition is an inertial fusion scheme in which fuel is first assembled and then heated to the ignition temperature with an external heating source. In this note we consider cone and shell implosions where the energy supplied by short pulse lasers is transported to the fuel by electrons. We describe possible failure modes for this scheme and how to overcome them. In particular, we describe two sources of cone tip failure, an axis jet driven from the compressed fuel mass and hard photon preheat leaking through the implosion shell, and laser prepulse that can change the position of laser absorption and the angular distribution of the emitted electrons.

Features of a point design for fast ignition

International Nuclear Information System (INIS)

Tabak, M.; Clark, D.; Town, R.J.; Key, M.H.; Amendt, P.; Ho, D.; Meeker, D.J.; Shay, H.D.; Lasinski, B.F.; Kemp, A.; Divol, L.; Mackinnon, A.J.; Patel, P.; Strozzi, D.; Grote, D.P.

2009-01-01

Fast Ignition is an inertial fusion scheme in which fuel is first assembled and then heated to the ignition temperature with an external heating source. In this note we consider cone and shell implosions where the energy supplied by short pulse lasers is transported to the fuel by electrons. We describe possible failure modes for this scheme and how to overcome them. In particular, we describe two sources of cone tip failure, an axis jet driven from the compressed fuel mass and hard photon preheat leaking through the implosion shell, and laser prepulse that can change the position of laser absorption and the angular distribution of the emitted electrons.

Maximum torque per ampere control of sensorless induction motor drives with dc offset and parameter compensation

International Nuclear Information System (INIS)

Markadeh, Gholamreza Arab; Hajian, Masood; Soltani, Jafar; Hosseinia, Saeed

2010-01-01

Field orientation control of induction machine (IM) drives is a well-known strategy which has a fast dynamic response. In this paper, the direct rotor flux field orientation control of speed sensorless IM drive is presented. A two level space vector modulation inverter is employed to generate the command stator voltage. In proposed control scheme, a maximum torque per ampere strategy is achieved using a so-called fast flux search method. Based on this method, for a given load torque and rotor speed, the magnitude of rotor reference flux is adjusted step by step until the effective value of stator current becomes minimized finally. In addition, using the IM fifth order model in the stationary reference frame, a nonlinear rotor flux observer is developed which is also capable of motor resistances and rotor speed simultaneously estimation. Moreover, a useful method is introduced for dc offset compensation which is a major problem of ac drives especially at low speeds. The proposed control idea is experimentally implemented in real time using a CPLD board synchronized with a personal computer. Simulation and experimental results are finally presented to confirm the validity and effectiveness of the proposed method.

Extending laser plasma accelerators into the mid-IR spectral domain with a next-generation ultra-fast CO2 laser

Science.gov (United States)

Pogorelsky, I. V.; Babzien, M.; Ben-Zvi, I.; Polyanskiy, M. N.; Skaritka, J.; Tresca, O.; Dover, N. P.; Najmudin, Z.; Lu, W.; Cook, N.; Ting, A.; Chen, Y.-H.

2016-03-01

Expanding the scope of relativistic plasma research to wavelengths longer than the λ/≈   0.8-1.1 μm range covered by conventional mode-locked solid-state lasers would offer attractive opportunities due to the quadratic scaling of the ponderomotive electron energy and critical plasma density with λ. Answering this quest, a next-generation mid-IR laser project is being advanced at the BNL ATF as a part of the user facility upgrade. We discuss the technical approach to this conceptually new 100 TW, 100 fs, λ  =   9-11 μm CO2 laser BESTIA (Brookhaven Experimental Supra-Terawatt Infrared at ATF) that encompasses several innovations applied for the first time to molecular gas lasers. BESTIA will enable new regimes of laser plasma accelerators. One example is shock-wave ion acceleration (SWA) from gas jets. We review ongoing efforts to achieve stable, monoenergetic proton acceleration by dynamically shaping the plasma density profile from a hydrogen gas target with laser-produced blast waves. At its full power, 100 TW BESTIA promises to achieve proton beams at an energy exceeding 200 MeV. In addition to ion acceleration in over-critical plasma, the ultra-intense mid-IR BESTIA will open up new opportunities in driving wakefields in tenuous plasmas, expanding the landscape of laser wakefield accelerator (LWFA) studies into the unexplored long-wavelength spectral domain. Simple wavelength scaling suggests that a 100 TW CO2 laser beam will be capable of efficiently generating plasma ‘bubbles’ a thousand times greater in volume compared with a near-IR solid state laser of an equivalent power. Combined with a femtosecond electron linac available at the ATF, this wavelength scaling will facilitate the study of external seeding and staging of LWFAs.

Evolution of bias field and offset piezoelectric coefficient in bulk lead zirconate titanate with fatigue

International Nuclear Information System (INIS)

Zhang Yong; Baturin, Ivan S.; Aulbach, Emil; Lupascu, Doru C.; Kholkin, Andrei L.; Shur, Vladimir Ya.; Roedel, Juergen

2005-01-01

Hysteresis loops of the piezoelectric coefficient, d 33 =f(E 3 ), are measured on virgin and fatigued lead zirconate titanate ceramics. Four parameters are directly extracted from the measurements: internal bias field E b , offset piezoelectric coefficient d offset , coercive field E c , and remnant piezoelectric coefficient d r . The reduction in d r displays the decreasing switchable polarization with fatigue cycling. E b and d offset are found to be linearly related. After thermal annealing, both offsets disappear, while the increase in E c and the reduction in d r withstand annealing. The microscopic entities responsible for the offsets are less stable than those for reduced switching

Photo-preionization stabilized high-pressure glow-discharge lasers

International Nuclear Information System (INIS)

Von Bergmann, H.M.

1980-07-01

Simple nanosecond stabilization and pulsing techniques were developed to excite high-pressure gas-discharge lasers at high overvoltages and high specific power loadings. The techniques were applied to a variety of ultraviolet and visible laser systems employing fast transmission line pulsers and conventional LC generators. The stabilization procedures are evaluated and the parameters which control the geometry and uniformity of the high-pressure glow discharges are investigated. A detailed study of the formation, distribution and spectral characteristics of the fast surface corona discharges is provided. The stabilization and pulsing techniques were used for the corona and glow discharge excitation of high-pressure ultraviolet N 2 lasers. A detailed spectrally- and temporally-resolved study of the gain, fluorescence and energy extraction characteristics of the atmospheric pressure N 2 plasmas is provided

12 CFR 313.46 - Notice of salary offset where FDIC is the paying agency.

Science.gov (United States)

2010-01-01

... 12 Banks and Banking 4 2010-01-01 2010-01-01 false Notice of salary offset where FDIC is the... AND RULES OF PRACTICE PROCEDURES FOR CORPORATE DEBT COLLECTION Salary Offset § 313.46 Notice of salary... shall send the employee a written notice of salary offset. Such notice shall advise the employee: (1...

12 CFR 1704.27 - Notice of salary offset where OFHEO is the paying agency.

Science.gov (United States)

2010-01-01

... 12 Banks and Banking 7 2010-01-01 2010-01-01 false Notice of salary offset where OFHEO is the..., DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT OFHEO ORGANIZATION AND FUNCTIONS DEBT COLLECTION Salary Offset § 1704.27 Notice of salary offset where OFHEO is the paying agency. (a) Notice. Upon issuance of a proper...

Regional impacts of a program for private forest carbon offset sales

Science.gov (United States)

Darius M. Adams; Ralph Alig; Greg Latta; Eric M. White

2011-01-01

Policymakers are examining wide range of alternatives for climate change mitigation, including carbon offset sales programs, to enhance sequestration in the forest sector. Under an offset sales program, on-the-ground forestry could change as result of both afforestation and modifications in the management of existing forests. These effects could vary markedly by region...

Experimental study of fast electron transport in dense plasmas

International Nuclear Information System (INIS)

Vaisseau, Xavier

2014-01-01

The framework of this PhD thesis is the inertial confinement fusion for energy production, in the context of the electron fast ignition scheme. The work consists in a characterization of the transport mechanisms of fast electrons, driven by intense laser pulses (10 19 - 10 20 W/cm 2 ) in both cold-solid and warm-dense matter. The first goal was to study the propagation of a fast electron beam, characterized by a current density ≥ 10 11 A/cm 2 , in aluminum targets initially heated close to the Fermi temperature by a counter-propagative planar shock. The planar compression geometry allowed us to discriminate the energy losses due to the resistive mechanisms from collisional ones by comparing solid and compressed targets of the same initial areal densities. We observed for the first time a significant increase of resistive energy losses in heated aluminum samples. The confrontation of the experimental data with the simulations, including a complete characterization of the electron source, of the target compression and of the fast electron transport, allowed us to study the time-evolution of the material resistivity. The estimated resistive electron stopping power in a warm-compressed target is of the same order as the collisional one. We studied the transport of the fast electrons generated in the interaction of a high-contrast laser pulse with a hollow copper cone, buried into a carbon layer, compressed by a counter-propagative planar shock. A X-ray imaging system allowed us to visualize the coupling of the laser pulse with the cone at different moments of the compression. This diagnostic, giving access to the fast electron spatial distribution, showed a fast electron generation in the entire volume of the cone for late times of compression, after shock breakout from the inner cone tip. For earlier times, the interaction at a high-contrast ensured that the source was contained within the cone tip, and the fast electron beam was collimated into the target depth by