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Sample records for stopping power

  1. Current stopping power analyses

    International Nuclear Information System (INIS)

    Porter, L.E.

    1983-01-01

    Modified Bethe-Bloch stopping power theory permits fairly accurate calculation of energy losses over a broad interval of projectile velocity v = νc insofar as several parameters appearing in the revised Bethe-Bloch formula have been corectly evaluated. Since the parameters cannot in general be ascertained by calculation from first principles, fits of theory to measurement remain the best method of evaluation. The parameters alluded to are: the target mean excitation energy; the shell correction scaling parameters; the composite single free parameter of the Barkas (projectile-z 3 ) effect correction formalism, and the strength of the correction term; the high velocity density effect correction parameter; and the low velocity charge state parameter. These parameters are discussed

  2. Stopping Power for Degenerate Electrons

    Energy Technology Data Exchange (ETDEWEB)

    Singleton, Jr., Robert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-05-16

    This is a first attempt at calculating the BPS stopping power with electron degeneracy corrections. Section I establishes some notation and basic facts. Section II outlines the basics of the calculation, and in Section III contains some brief notes on how to proceed with the details of the calculation. The remaining work for the calculation starts with Section III.

  3. Electron and Positron Stopping Powers of Materials

    Science.gov (United States)

    SRD 7 NIST Electron and Positron Stopping Powers of Materials (PC database for purchase)   The EPSTAR database provides rapid calculations of stopping powers (collisional, radiative, and total), CSDA ranges, radiation yields and density effect corrections for incident electrons or positrons with kinetic energies from 1 keV to 10 GeV, and for any chemically defined target material.

  4. Measurement of stopping power of heavy ions

    International Nuclear Information System (INIS)

    Kitahara, Tetsuo

    1981-01-01

    The stopping power of heavy ions is discussed. In the low energy region, heavy ions keep some of their orbital electrons, and have equilibrium electron charge. The stopping power of penetrating particles depends on this effective charge. At present, it is hard to estimate this effective charge theoretically, accordingly, the estimation is made experimentally. Another difficulty in this estimation is that the Born approximation is not effective for heavy ions. In the low energy region, electronic stopping and nuclear stopping contribute to the stopping power. For the electronic stopping, a formula for the stopping power was given by Lindhard et al. The experimental values were obtained at GSI, and are inconsistent with the estimation by the Lindhard's formula. In the high energy region, where the Born approximation can be used, the Bethe's formula is applied, but the experimental data are scarce. Oscillations are seen in the Z dependence graph of the experimental stopping cross sections. Experimental works on the stopping power have been done. The differential and the integral methods were carried out. (Kato, T.)

  5. Empirical stopping powers for ions in solids

    International Nuclear Information System (INIS)

    Ziegler, J.F.; Biersack, J.P.; Littmark, U.

    1983-01-01

    The work of Brandt and collaborators on low energy ion stopping powers has been extended to create an empirical formulation for the stopping of ions in solids. The result is a simple computer program (about 60 lines of code) which calculates stopping powers from zero to 100 MeV/amu for all ions in all elemental solids. This code has been compared to the data in about 2000 papers, and has a standard error of 9% for energies above keV/amu. This approach includes high energy relativistic effects and shell-corrections. In the medium energy range it uses stopping theory based on the local-density approximation and Lindhard stopping in a free electron gas. This is applied to realistic Hartree-Fock charge distributions for crystalline solids. In the low energy range it uses the Brandt concepts of ion stripping relative to the Fermi velocity of solids, and also his formalism for the relation of projectile ionization to its effective charge. The details of the calculation are presented, and a broad comparison is shown with experiment. Special comparative examples are shown of both the low energy stopping power oscillations which depend on the atomic number of the ion, and also of the target

  6. Electron stopping powers for transport calculations

    International Nuclear Information System (INIS)

    Berger, M.J.

    1988-01-01

    The reliability of radiation transport calculations depends on the accuracy of the input cross sections. Therefore, it is essential to review and update the cross sections from time to time. Even though the main interest of the author's group at NBS is in transport calculations and their applications, the group spends almost as much time on the analysis and preparation of cross sections as on the development of transport codes. Stopping powers, photon attenuation coefficients, bremsstrahlung cross sections, and elastic-scattering cross sections in recent years have claimed attention. This chapter deals with electron stopping powers (with emphasis on collision stopping powers), and reviews the state of the art as reflected by Report 37 of the International Commission on Radiation Units and Measurements

  7. Stopping Power Measurements: Implications in Nuclear Astrophysics

    International Nuclear Information System (INIS)

    Carmen Angulo; Thierry Delbar; Jean-Sebastien Graulich; Pierre Leleux

    1999-01-01

    The stopping powers of C, CH 2 , Al, Ni, and polyvinylchloride (PVC) for several light ions ( 9 Be, 11 B, 12 C, 14 N, 16 O, 19 F, 20 Ne) with an incident energy of 1 MeV/amu have been measured at the Louvain-la-Neuve cyclotron facility. Stopping powers are given relative to the one for 5.5 MeV 4 He ions with an uncertainty of less than 1%. We compare our results with two widely used semiempirical models and we discuss some implications in nuclear astrophysics studies

  8. Ab initio electronic stopping power in materials

    International Nuclear Information System (INIS)

    Shukri, Abdullah-Atef

    2015-01-01

    The average energy loss of an ion per unit path length when it is moving through the matter is named the stopping power. The knowledge of the stopping power is essential for a variety of contemporary applications which depend on the transport of ions in matter, especially ion beam analysis techniques and ion implantation. Most noticeably, the use of proton or heavier ion beams in radiotherapy requires the knowledge of the stopping power. Whereas experimental data are readily available for elemental solids, the data are much more scarce for compounds. The linear response dielectric formalism has been widely used in the past to study the electronic stopping power. In particular, the famous pioneering calculations due to Lindhard evaluate the electronic stopping power of a free electron gas. In this thesis, we develop a fully ab initio scheme based on linear response time-dependent density functional theory to predict the impact parameter averaged quantity named the random electronic stopping power (RESP) of materials without any empirical fitting. The purpose is to be capable of predicting the outcome of experiments without any knowledge of target material besides its crystallographic structure. Our developments have been done within the open source ab initio code named ABINIT, where two approximations are now available: the Random-Phase Approximation (RPA) and the Adiabatic Local Density Approximation (ALDA). Furthermore, a new method named 'extrapolation scheme' have been introduced to overcome the stringent convergence issues we have encountered. These convergence issues have prevented the previous studies in literature from offering a direct comparison to experiment. First of all, we demonstrate the importance of describing the realistic ab initio electronic structure by comparing with the historical Lindhard stopping power evaluation. Whereas the Lindhard stopping power provides a first order description that captures the general features of the

  9. Seismic stops for nuclear power plants

    International Nuclear Information System (INIS)

    Cloud, R.L.; Leung, J.S.M.; Anderson, P.H.

    1989-01-01

    In the regulated world of nuclear power, the need to have analytical proof of performance in hypothetical design-basis events such as earth quakes has placed a premium on design configurations that are mathematically tractable and easily analyzed. This is particularly true for the piping design. Depending on how the piping analyses are organized and on how old the plant is, there may be from 200 to 1000 separate piping runs to be designed, analyzed, and qualified. In this situation, the development of snubbers seemed like the answer to a piping engineer's prayer. At any place where seismic support was required but thermal motion had to be accommodated, a snubber could be specified. But, as experience has now shown, the program was solved only on paper. This article presents an alternative to conventional snubbers. These new devices, termed Seismic Stops are designed to replace snubbers directly and look like snubbers on the outside. But their design is based on a completely different principle. The original concept has adapted from early seismic-resistant pipe support designs used on fossil power plants in California. The fundamental idea is to provide a space envelope in which the pipe can expand freely between the hot and cold positions, but cannot move outside the envelope. Seismic Stops are designed to transmit any possible impact load, as would occur in an earthquake, away from the pipe itself to the Seismic Stop. The Seismic Stop pipe support is shown

  10. Simulations of enhanced ion stopping power experiments

    International Nuclear Information System (INIS)

    Mehlhorn, T.A.; Maenchen, J.E.; Olsen, J.N.; Johnson, D.J.

    1984-01-01

    As the material in an ICF target is heated and ionized by an intense ion beam, the ion stopping power changes from that of neutral atoms. This changes the energy deposition characteristics of the ion beam and thereby can profoundly influence the target dynamics. An accurate ion energy deposition model is important for designing ICF targets that perform in an optimal fashion. An experiment to measure a time-resolved ion stopping power history in a partially ionized target is being fielded on the PROTO I accelerator at Sandia Labs. This experiment utilizes a voltage ramped Thomson parabola to provide a time-history of the ion energy incident upon and exiting from a cylindrical target foil

  11. Measurement of stopping power of light ions

    International Nuclear Information System (INIS)

    Sakamoto, Naoki

    1981-01-01

    The stopping power of light ions penetrating various materials has been measured. The data of proton stopping power and the mean ionization potentials are presented. The experiments were made by using the 6.75 MeV protons from a cyclotron and the protons in the energy range from 3 to 9 MeV from a tandem Van de Graaff. The windows with and without sample-foils were rotated in front of a semiconductor detector, and the measured energy loss and the thickness of the sample foils were used to estimate the energy loss at the mean energy of protons in the samples. The analyses were made by considering the inner shell correction, Z 1 3 correction and the Bloch correction. The mean ionization potentials were derived from the data. (Kato, T.)

  12. Electron mass stopping power in H2

    Science.gov (United States)

    Fursa, Dmitry V.; Zammit, Mark C.; Threlfall, Robert L.; Savage, Jeremy S.; Bray, Igor

    2017-08-01

    Calculations of electron mass stopping power (SP) of electrons in H2 have been performed using the convergent close-coupling method for incident electron energies up to 2000 eV. Convergence of the calculated SP has been established by increasing the size of the close-coupling expansion from 9 to 491 states. Good agreement was found with the SP measurements of Munoz et al. [Chem. Phys. Lett. 433, 253 (2007), 10.1016/j.cplett.2006.10.114].

  13. Stopping-power ratios for dosimetry

    International Nuclear Information System (INIS)

    Andreo, P.

    1988-01-01

    The determination of the absorbed dose at a specified location in a medium irradiated with an electron or photon beam normally consists of two steps: (1) the determination of the mean absorbed dose to a detector by using a calibration factor or performing an absolute measurement, (2) the determination of the absorbed dose to the medium at the point of interest by calculations based on the knowledge of the absorbed dose to the detector and the different stopping and scattering properties of the medium and the detector material. When the influence of the detector is so small that the electron fluence in the medium is not modified, the ratio of the mass collision stopping power of the two materials accounts for the differences in energy deposition, and provides a conversion factor to relate the absorbed dose in both materials. Today, all national and international dosimetry protocols and codes of practice are based on such procedures, and the user easily can carry out these steps using tabulated data to convert a measured quantity to absorbed dose in the irradiated medium at the location of interest. Effects due to the spatial extension of the detector are taken into account using perturbation correction factors. The Monte Carlo method has become the most common and powerful calculational technique for determining the electron fluence (energy spectra) under different irradiation conditions. Cavity theory is then used to calculate stopping-power ratios. In this chapter, the different steps needed to evaluate s-ratios will be considered, emphasizing the different types of cavity-theory integrals and the Monte Carlo techniques used to derive the necessary electron spectra in the range of energies commonly used in radiation dosimetry, i.e., photon and electron beams with energies up to 50 MeV

  14. 10 blows that stopped nuclear power

    International Nuclear Information System (INIS)

    Komanoff, C.

    1991-01-01

    The author describes these 10 blows in chronological order, 1973 through 1981, namely: (1) Arab Oil Embargo; (2) India Explodes a Bomb; (3) NRC replaces AEC; (4) Fire at Browns Ferry; (5) General Electric and NRC Engineers switch Sides; (6) Amory Lovins Recasts the Energy Debate; (7) The Seabrook Occupation; (8) The Three Mile Island Accident; (9) Federal Reserve Tightens the Money Supply; and (1) Pacific Gas and Electric Co. Gets it Backwards at Diablo Canyon. he stops there, not including the Washington Public Power Supply fiasco and the Chernobyl disaster, feeling nuclear expansion was essentially foreclosed without them. Further, he feels nuclear power seems fated to be forever at the mercy of forces beyond its control

  15. Stopping power for heavy ions in low energy region

    International Nuclear Information System (INIS)

    Kitagawa, Mitsuo

    1983-01-01

    Review is made for the study on the power for stopping heavy ions. The studies on the power for stopping heavy ions passing through materials have been developed in the last twenty years due to the accuracy improvement in the data analysis of the power for stopping light ions, the requirement of data establishment on the power for stopping heavy ions from fusion research and the development of the experimental studies by heavy-ion accelerators. The relation between the analysis of the power for stopping heavy ions and the power for stopping light ions is described from the standpoint that the results on the power for stopping light ions serve as the guide for the study on the power for stopping heavy ions. Both at present and in future. The analysis of stopping power data with the accuracy from +-10 to 20 % is possible from the theoretical analysis of effective electric charge and its systematic table of the numerical data. The outline of the scaling rule on effective electric charge is discussed. The deviation of the experimental data from the scaling rule is discussed by comparing with the measured values of effective electric charge ratio. Various analyses of the power for stopping heavy ions are summarized. (Asami, T.)

  16. Stopping power, its meaning, and its general characteristics

    International Nuclear Information System (INIS)

    Inokuti, Mitio.

    1995-01-01

    This essay presents remarks on the meaning of stopping, power and of its magnitude. More precisely, the first set of remarks concerns the connection of stopping power with elements of particle-transport theory, which describes particle transport and its consequences in full detail, including its stochastic aspects. The second set of remarks concerns the magnitude of the stopping power of a material and its relation with the material's electronic structure and other properties

  17. The IAEA stopping power database, following the trends in stopping power of ions in matter

    Science.gov (United States)

    Montanari, C. C.; Dimitriou, P.

    2017-10-01

    The aim of this work is to present an overview of the state of art of the energy loss of ions in matter, based on the new developments in the stopping power database of the International Atomic Energy Agency (IAEA). This exhaustive collection of experimental data, graphs, programs and comparisons, is the legacy of Helmut Paul, who made it accessible to the global scientific community, and has been extensively employed in theoretical and experimental research during the last 25 years. The field of stopping power in matter is evolving, with new trends in materials of interest, including oxides, nitrides, polymers, and biological targets. Our goal is to identify areas of interest and emerging data needs to meet the requirements of a continuously developing user community.

  18. Stopping, goal-conflict, trait anxiety and frontal rhythmic power in the stop-signal task.

    Science.gov (United States)

    Neo, Phoebe S-H; Thurlow, Jane K; McNaughton, Neil

    2011-12-01

    The medial right frontal cortex is implicated in fast stopping of an initiated motor action in the stop-signal task (SST). To assess whether this region is also involved in the slower behavioural inhibition induced by goal conflict, we tested for effects of goal conflict (when stop and go tendencies are balanced) on low-frequency rhythms in the SST. Stop trials were divided, according to the delays at which the stop signal occurred, into short-, intermediate-, and long-delay trials. Consistent with goal-conflict processing, intermediate-delay trials were associated with greater 7-8 Hz EEG power than short- or long-delay trials at medial right frontal sites (Fz, F4, and F8). At F8, 7-8 Hz power was linked to high trait anxiety and neuroticism. A separate 4-7 Hz power increase was also seen in stop, relative to go, trials, but this was independent of delay, was maximal at the central midline site Cz, and predicted faster stopping. Together with previous data on the SST, these results suggest that the right frontal region could be involved in multiple inhibition mechanisms. We propose a hierarchical model of the control of stopping that integrates the literature on the neural control of fast motor stopping with that on slower, motive-directed behavioural inhibition.

  19. Range and stopping power for slow particles

    International Nuclear Information System (INIS)

    Bastiano, M.; Fernandez, J. E.; Molinari, V. G.

    1997-01-01

    Generally, the effects of thermal agitation and chemical bonding of the target atoms need to be taken into account to compute properly the range and stopping power of particles. These two effects, however, complicate very much the calculation of the above parameters, and for this reason are usually neglected. In fact, when the energy of the test particles (t.p.) is sufficiently high compared to the thermal or bonding energies, these two effects can be safely disregarded. When the energy of the t.p. is of the same order of the thermal agitation or the chemical bonding, on the other hand, such approximation is not realistic, and to obtain meaningful results one must take into account the velocity distribution of the field particles (f.p.). The aim of this paper is to present a simple model describing the transport of particles (e.g., electrons) in the thermal zone, considering the thermal agitation of f.p. with an arbitrary distribution. It will be shown that in the first part of the slowing down the kinetic energy of t.p. is partially transformed into temperature. In the second part, the temperature tends to reach the equilibrium temperature, while average velocity of t.p. becomes zero. (author)

  20. Ion Stopping Powers and Ranges Whenever You Need Them

    DEFF Research Database (Denmark)

    Bassler, Niels; Christensen, Casper; Tørresø, Jesper Rosholm

    A new app "Electronic Stopping Power" for Android mobile phones and tablets, looks up stopping powers using the ICRU 49 (protons and alphas) and the revised ICRU 73 (lithium and heavier ions) tables. In addition, also MSTAR and an implementation of the Bethe equation expanded to low energies...

  1. Stopping power. Projectile and target modeled as oscillators

    International Nuclear Information System (INIS)

    Stevanovic, N.; Nikezic, D.

    2005-01-01

    In this Letter the collision of two quantum harmonic oscillators was considered. The oscillators interact through the Coulomb interaction. Stopping power of projectile was calculated assuming that both, target and projectile may be excited. It has been shown that the frequency of the projectile oscillation, ω p influences on stopping power, particularly in the region of Bragg peak. If, ω p ->0 is substitute in the expression for stopping power derived in this Letter, then it comes to the form when the projectile has been treated as point like charged particle

  2. Nuclear stopping power at high energies

    International Nuclear Information System (INIS)

    Date, S.; Gyulassy, M.; Sumiyoshi, H.

    1985-03-01

    Recent p + A → p + X data are analyzed within the context of the multi-chain and additive quark models. We deduce the average energy loss of a baryon as a function of distance traversed in nuclear matter. Consistency of the multi-chain model is checked by comparing the predictions for p + A → π +- + X with data. We discuss the space-time development of baryon stopping and show how longitudinal growth limits the energy deposition per unit length. Predictions are made for the proton spectra to be measured in nucleus-nucleus collisions at CERN and BNL. Finally, we conclude that the stopping domain for central collisions of heavy ions extends up to center of mass kinetic energies KEsub(em) asymptotically equals 3 +- 1 AGev. (author)

  3. STARCODES, Stopping Power and Ranges for Electrons, Protons, He

    International Nuclear Information System (INIS)

    2000-01-01

    1 - Description of program or function: The 'STAR CODES', ESTAR, PSTAR, and ASTAR, calculate stopping-power and range tables for electrons, protons, and helium ions (alphas), according to methods described in ICRU Reports 37 and 39. 2 - Method of solution: Collision stopping powers are calculated from the theory of Bethe (1930, 1932), with a density-effect correction evaluated according to Sternheimer (1952, 1982). The stopping-power formula contains an important parameter, the mean excitation energy (I-value), which characterizes the stopping properties of a material. The codes provide output for electrons in any stopping material (279 provided) and for protons and helium ions in 74 materials. The calculations include the 1) Collision stopping power, 2) Radiative stopping power (electrons only), 3) Nuclear stopping power (protons and helium ions), 4) Total stopping power, 5) CSDA range, 6) Projected range (protons and helium ions), 7) Density effect parameter (electrons), 8) Radiation yield (electrons), and 9) Detour factor (protons and helium ions). Standard energy grids and files of elements w/ionization-excitation information are included with lookup table capabilities. 3 - Restrictions on the complexity of the problem: The minimum energies used in the calculations are at 1 KeV (protons and helium ions) and 10 KeV (electrons), and the maximum are 1 GeV. The standard energy grids are set at 81 for electrons, equally spaced (logarithmically), 133 for protons, and 122 for helium ions. The lower energy electron calculations (< 10 KeV) have up to 5-10% errors and are considered too fallable

  4. Stopping power of K electrons at extreme relativistic energies

    International Nuclear Information System (INIS)

    Leung, P.T.; Rustgi, M.L.

    1983-01-01

    The recent work of Anholt on K-vacancy production by relativistic projectiles has been applied to calculate the stopping power of the K electrons. The results show that for protons of energy approx.10 3 GeV and heavy target elements, the relativistic contributions to the stopping power amount to several times the resuls due to the longitudinal terms obtained from Walske's work

  5. Stopping power of degenerate electron liquid at metallic densities

    International Nuclear Information System (INIS)

    Tanaka, Shigenori; Ichimaru, Setsuo

    1985-01-01

    We calculate the stopping power of the degenerate electron liquid at metallic densities in the dielectric formalism. The strong Coulomb-coupling effects beyond the random-phase approximation are taken into account through the static and dynamic local-field corrections. It is shown that those strong-coupling and dynamic effects act to enhance the stopping power substantially in the low-velocity regime, leading to an improved agreement with experimental data. (author)

  6. Simulation on effect of stopping nuclear power generation

    International Nuclear Information System (INIS)

    Yajima, Masayuki; Kumakura, Osamu; Sakurai, Norihisa; Nagata, Yutaka; Hattori, Tsuneaki

    1990-01-01

    The effects that the stopping of nuclear power generation exerts on the price of primary energy such as petroleum, LNG and coal and the trend of Japanese energy and economy are analyzed by using the medium term economy forecasting system. In the simulation, the case of stopping nuclear power generation in seven countries of OECD is supposed, and as for the process of stopping, two cases of immediate stopping and stopping by gradual reduction are set up. The models used for the simulation are the world energy model, the competition among energies model and the multiple category model. By the decrease of nuclear power generation, thermal power generation increases, and the demand of fossil fuel increases. As the result, the price of fossil fuel rises (the world energy model), and the price of fossil fuel imported to Japan rises. Also the quantity of fossil fuel import to Japan increase. These price rise and quantity increase exert deflation effect to Japanese economy (the multiple category model). The price rise of fossil fuel affects the competition among energies in Japan through the relative change of secondary energy price (the competition among energies model). The impact to the world and to Japan is discussed. (K.I.)

  7. New developments in stopping power for fast ions

    International Nuclear Information System (INIS)

    Paul, Helmut

    2007-01-01

    We discuss the available stopping power tables and codes, and new experimental methods. Among the semi-empirical stopping power tables, SRIM and MSTAR describe experimental data best. Of the recent theoretical stopping codes CasP, PASS, TCS and dielectric formalism, all describe some data well. PASS is the only theoretical code with an extended table for many ions and targets, but on the average, its predictive value at low energies is less than that of SRIM or MSTAR. The first-principle extended classical trajectory Monte Carlo method is very promising. The ToF-E ERDA arrangements have made it possible to produce accurate data for many ion-target combinations. A new liquid jet target method promises data for liquid water which is an important substance for medical dosimetry

  8. Theoretical model for calculation of molecular stopping power

    International Nuclear Information System (INIS)

    Xu, Y.J.

    1984-01-01

    A modified local plasma model based on the work of Linhard-Winther, Bethe, Brown, and Walske is established. The Gordon-Kim's molecular charged density model is employed to obtain a formula to evaluate the stopping power of many useful molecular systems. The stopping power of H 2 and He gas was calculated for incident proton energy ranging from 100 KeV to 2.5 MeV. The stopping power of O 2 , N 2 , and water vapor was also calculated for incident proton energy ranging from 40 keV to 2.5 MeV. Good agreement with experimental data was obtained. A discussion of molecular effects leading to departure from Bragg's rule is presented. The equipartition rule and the effect of nuclear momentum recoiling in stopping power are also discussed in the appendix. The calculation procedure presented hopefully can easily be extended to include the most useful organic systems such as the molecules composed of carbon, nitrogen, hydrogen and oxygen which are useful in radiation protection field

  9. Measurement of the Barkas effect around the stopping-power maximum for light and heavy targets

    International Nuclear Information System (INIS)

    Moeller, S.P.; Knudsen, H.; Mikkelsen, U.; Paludan, K.; Morenzoni, E.

    1997-01-01

    The first direct measurements of antiproton stopping powers around the stopping power maximum are presented. The LEAR antiproton-beam of 5.9 MeV is degraded to 50-700 keV, and the energy-loss is found by measuring the antiproton velocity before and after the target. The antiproton stopping powers of Si and Au are found to be reduced by 30 and 40% near the electronic stopping power maximum as compared to the equivalent proton stopping power. The Barkas effect, that is the stopping power difference between protons and antiprotons, is extracted and compared to theoretical estimates. (orig.)

  10. Electronic Stopping Power in LiF from First Principles

    International Nuclear Information System (INIS)

    Pruneda, J. M.; Sanchez-Portal, D.; Arnau, A.; Juaristi, J. I.; Artacho, Emilio

    2007-01-01

    Using time-dependent density-functional theory we calculate from first principles the rate of energy transfer from a moving proton or antiproton to the electrons of an insulating material, LiF. The behavior of the electronic stopping power versus projectile velocity displays an effective threshold velocity of ∼0.2 a.u. for the proton, consistent with recent experimental observations, and also for the antiproton. The calculated proton/antiproton stopping-power ratio is ∼2.4 at velocities slightly above the threshold (v∼0.4 a.u.), as compared to the experimental value of 2.1. The projectile energy loss mechanism is observed to be extremely local

  11. Stopping power for heavy ions in gases: a comparative study

    International Nuclear Information System (INIS)

    Diwan, P.K.; Singh, Lakhwant; Singh, Gurinder; Shyam Kumar

    1999-01-01

    The accurate knowledge of stopping power for heavy ions in gases is of paramount importance in nuclear reaction studies for the identification of reaction products involving ΔE-E telescope detectors. In the present work, it has been calculated the stopping power values for different heavy ions, such as Ne, Ar, Cu, Kr and Ag in various gas absorbers like H 2 , He, N 2 , Ne, Ar, Kr and Xe in the energy domain ∼ 2.5-6 MeV/n using the SRIM-98 code recently developed by Ziegler and the formulations of Benton and Henke, Hubert et al, Mukherjee and Nayak and Northcliffe and Schilling. This study has been undertaken in order to establish the validity of various semiempirical formulations for gas targets

  12. Simultaneous wide-range stopping power determination for several ions

    Energy Technology Data Exchange (ETDEWEB)

    Alanko, T. E-mail: tommi.alanko@phys.jyu.fi; Trzaska, W.H.; Lyapin, V.; Raeisaenen, J.; Tiourine, G.; Virtanen, A

    2002-05-01

    A new procedure to extract simultaneously continuous stopping power curves for several ions and several absorbers over a wide energy range and with statistical errors reduced to negligible level is presented. The method combines our novel time-of-flight based method with the capability of our K130 cyclotron and ECR ion-source to produce the so-called ion cocktails. The potential of the method is demonstrated with a 6.0 MeV/u cocktail consisting of {sup 16}O{sup 4+}, {sup 28}Si{sup 7+} and {sup 40}Ar{sup 10+} ions. The stopping power in polycarbonate in the energy range of 0.35-5 MeV/u has been determined with absolute uncertainty of less than 2.3% and with relative below 0.2%. The results are compared with literature data and with SRIM2000 parameterisation including cores and bonds corrections.

  13. Potential information and stopping power from channeling in diamond

    International Nuclear Information System (INIS)

    Edge, R.D.; Derry, J.E.; Fearick, R.W.; Sellschop, J.P.F.

    1983-01-01

    When a carefully cleaned diamond crystal was bombarded with helium nuclei parallel to a low index plane, up to seven peaks in the energy spectrum of backscattered ions were seen. These arose from particles oscillating to and fro across the channel as they progressed along it. Spectra taken with ions incident in different directions in the same plane allowed both the wavelengths of the oscillations in the channel, lambda, and the stopping power within the channel to be obtained. The character of the oscillations changed as the beam deviated from exact alignment with the channel, giving the highest maximum at an angle /psi/ /SUB m/ to the channel. Calculations based on those of Barrett employing lambda, /psi/ /SUB m/, and the stopping power showed a smoother potential for the (111) planar channel, which has a larger spacing, than (100) and (110). The energy dependence of the stopping power and oscillation wavelength was also determined from 0.2 to 1.2 MeV for the (110) planar channel

  14. Stopping powers of solids for low-energy protons

    International Nuclear Information System (INIS)

    Ashley, J.C.; Ritchie, R.H.

    1984-01-01

    Electron gas models are useful approximations for describing the valence electron response of a solid to the passage of a charged particle. A simple free-electron gas model was used by Fermi and Teller to estimate the time required for a mesotron to be stopped in various solids. More recent work has employed the Lindhard dielectric response function, or approximations thereto, for calculations of the valence electron contributions to energy loss per unit pathlength for protons. Such calculations have generally shown rather poor agreement with experimental data for low-energy protons (velocity small compared to the Fermi velocity, v<< v/sub F/). The purpose of this paper is to draw attention to a recent calculation of the stopping power for slow protons using a density-functional formalism. These new results have been shown to give good agreement with experimental data and thus should provide valuable theoretical guidance in estimating stopping powers of solids for which no experimental data are available

  15. Electron stopping power in dosimetry. I. Evolution and present status

    International Nuclear Information System (INIS)

    Andreo, P.

    1985-01-01

    A review of the theory and the evolution of the calculation of the collision stopping power of electrons has been performed. Special emphasis has been given to those aspects and materials used in the dosimetry electron and photon beams. The important parameters mean excitation energy and the density effect correction are considered in detail to clarify the different models and data available at the present time. Updated data, comparisons and results are given using the formulation and numerical values described in this work. (author)

  16. Stopping power for particle therapy: the generic library libdEdx and clinically relevant stopping-power ratios for light ions

    DEFF Research Database (Denmark)

    Lühr, Armin Christian; Toftegaard, Jakob; Kantemiris, Ioannis

    2012-01-01

    to be known accurately for dosimetry. Methods: An open-source computer library called libdEdx (library for energy loss per unit path length, dE/dx, calculations) is developed, providing stopping-power data from data tables and computer programs as well as a stopping-power formula comprising a large list...

  17. Contribution of inner shell electrons to position-dependent stopping powers of a crystal surface

    International Nuclear Information System (INIS)

    Narumi, Kazumasa; Fujii, Yoshikazu; Kishine, Keiji; Kurakake, Hiroshi; Kimura, Kenji; Mannami, Michi-hiko

    1994-01-01

    Position-dependent stopping powers of the (001) surface of SnTe single crystal for specularly reflected 15 - 200 keV H + ions are studied. The position dependence of the experimental stopping powers varies with the energy of ions. From the comparison with the theoretical stopping powers based on both the single ion-electron collision and the collective excitation of the valence electrons, it is concluded that the observed change in the position-dependent stopping powers with energy of H + is due to the variation of contribution of inner shell electrons to stopping. (author)

  18. Materials specificity, quantum length scales, and stopping powers

    International Nuclear Information System (INIS)

    Trickey, S.B.; Wu, Jin Z.; Sabin, John R.

    1994-01-01

    Standard arguments, based primarily on behavior at high projectile energies and classical notions of thickness as a continuous parameter, assert that stopping powers are only modestly affected by target chemistry and aggregation and by sample thickness if the thickness is ''sufficiently small'' (and channeling is avoided). Sufficient thinness usually is defined in terms of freedom from multiple scattering and from projectile charge-state changes. The growing technological importance of extremely thin material layers (e.g. microelectronics) has motivated re-examination of both the thickness and aggregation-state assertions. We give arguments to show that both are inadequate and reappraise recent computations in confirmation. A particular focus is the proper definition of thickness for an ultrathin film of ν atomic planes (ν=1, 2, 3,.s). ((orig.))

  19. Stopping powers and ranges for the heaviest atoms

    International Nuclear Information System (INIS)

    Sagaidak, Roman N.; Utyonkov, Vladimir K.; Dmitriev, Sergey N.

    2015-01-01

    Slowing down and stopping of the heaviest atoms, products of the fusion–evaporation nuclear reactions, during their passage through the Dubna gas-filled recoil separator has been studied using TRIM simulations. The study is important for experiments on the synthesis of super-heavy elements (SHEs) with atomic numbers around Z_P = 114 produced with accelerated heavy ion (HI) beams and extracted with a separator for their detection. The average Mylar stopping power (SP) values obtained with the simulations for HIs with 82 ⩽ Z_P ⩽ 92 reveal almost the same magnitudes, allowing extrapolation to the region of Z_P > 92. Similar extrapolation of the ranges in an He + Ar gas mixture leads to rather small values for the heaviest atoms (Z_P ⩾ 102) as compared to the range for U. The extrapolated values have large uncertainties and should be verified with different approaches. Available SP data obtained for HIs with 18 ⩽ Z_P ⩽ 92 at energies E < 20 MeV/u have been analysed within various semi-empirical approaches. The analysis has shown that existing parameterizations give Mylar SP values for Z_P ⩾ 82 that are very different from each other at energies of interest (around 0.1 MeV/u). We propose to use a general approach based on the HI effective charge parameterization obtained with available SP data for HIs and the hydrogen SP and effective charge corresponding to the same velocity and stopping medium as those for HIs. In this manner, the SPs of the gases H_2, He, C_4H_1_0, and Ar as well as those of the solids Mylar, C, Al, and Ti have been obtained for any atoms with Z_P ⩾ 18 (including the heaviest ones) at their reduced velocities 0.03 ⩽ V_r_e_d ⩽ 5.0. The SP values derived in such a way seem to be more reliable compared to the existing semi-empirical calculations and can be used in the conditioning of experiments on the synthesis of SHEs.

  20. Stopping powers of energetic electrons penetrating condensed matter-theory and application

    International Nuclear Information System (INIS)

    Tan Zhenyu; Xia Yueyuan

    2004-01-01

    In this review article, the motivation of studying inelastic energy loss for energetic electrons penetrating through matter and the corresponding technological importance have been outlined. The theoretical development and method for the calculation of stopping powers are described. The stopping power data tables for a group of polymers and bioorganic compounds are presented, and the application aspects of the stopping power data are briefly discussed. (authors)

  1. Subshell stopping power of the elements for protons in the Born approximation

    International Nuclear Information System (INIS)

    McGuire, E.J.

    1982-01-01

    The generalized oscillator-strength formulation of the Born approximation was used to generate a large sample of subshell excitation and ionization generalized oscillator strengths across the periodic table. These were used to calculate the excitation and ionization contributions to the proton stopping power by individual subshells. The subshell ionization stopping powers are expressed in scaled form, depending on the subshell ionization energy. Detailed comparison of the calculated total proton stopping power is in good agreement with experiment across the periodic table. Detailed calculations show the importance of outer-shell ionization and excitation to the total stopping power for protons with energy less than 10 MeV

  2. The calculation of proton and secondary electron stopping powers in liquid water

    International Nuclear Information System (INIS)

    Marouane, Abdelhak; Inchaouh, Jamal; Ouaskit, Said; Fathi, Ahmed

    2012-01-01

    The stopping power of energetic protons in liquid water has been calculated using a new model based on different theoretical and semi-empirical approaches. In this model, we consider the relativistic corrections along with the electronic and nuclear stopping power. The present work accounts for the different interactions made with electrons and nuclei inside the target. Interactions of the incident particle with the target's electrons dominate in the high energy regime; in the low energy regime, the interactions of the projectile with the target nuclei contribute importantly and are included in the calculation. We also compute the stopping cross sections and the stopping power of secondary electrons ejected from proton and hydrogen ionization impact, and generated by hydrogen electron loss processes. The consideration of secondary electrons' stopping power can contribute to the study of nano-dosimetry. Our results are in good agreement with existing experimental data. This calculation model can be useful for different applications in medical physics and space radiation health, such as hadron therapy for cancer treatment or radiation protection for astronauts. - Highlights: ► We discussed the stopping cross sections at the Bragg peak region of primary and secondary processes. ► We considered the corrections of incident particle energy focusing on the Rudds semi-empirical model. ► We calculated the electronic and nuclear stopping power, and we deduced the total stopping power. ► We calculated the stopping power of the secondary electrons.

  3. Study of the chemical binding effect on the molecular stopping power of V2O5

    International Nuclear Information System (INIS)

    Eisenbarth, S.R.

    1981-01-01

    The stopping powers of V and V 2 O 5 have been measured for helium ions with energies from 0.3 to 2.0 MeV and probable errors of 2.2 and 3.0%, respectively. The vanadium stopping power was 12 and 14% lower than the previous measurement of Chu and Powers (1969) and 2 to 5% lower than the semi-empirical values of Chu and Zeigler (1974) in this energy range. The V 2 O 5 stopping power was found to be 2 to 3.5% lower than the Bragg rule curve calculated with the molecular oxygen values of Bourland, Chu, and Powers (1971) and the present vanadium stopping power. The use of Bragg's rule to extract the oxygen contribution to the molecular stopping power of V 2 O 5 results in a solid oxygen stopping power which is in good agreement with the solid molecular oxygen measurement of Chu, Braun, Davies, Matsunami, and Thompson (1978) and approximately 5% higher than Feng's value (1974) obtained from metal oxides which have wide energy band gaps. The present experiment cautions against the use of a common stopping power for oxygen in Bragg rule calculations for solid compounds as purposed by Feng and by Zeigler and Chu (1976)

  4. Monte Carlo Simulations on the water-to-air stopping power ratio for carbon ion dosimetry

    DEFF Research Database (Denmark)

    Henkner, Katrin; Bassler, Niels; Sobolevsky, Nikolai

    2009-01-01

    Many papers discussed the I value for water given by the ICRU, concluding that a value of about 80±2  eV instead of 67.2  eV would reproduce measured ion depth-dose curves. A change in the I value for water would have an effect on the stopping power and, hence, on the water-to-air stopping power...... tables and ICRU reports. The stopping power ratio is calculated via track-length dose calculation with SHIELD-HIT07. In the calculations, the stopping power ratio is reduced to a value of 1.119 in the plateau region as compared to the cited value of 1.13 in IAEA TRS-398. At low energies the stopping...

  5. Stopping Power of Solid Argon for Helium Ions

    DEFF Research Database (Denmark)

    Besenbacher, F.; Bøttiger, Jørgen; Grauersen, O.

    1981-01-01

    By means of the Rutherford-backscattering method, the stopping cross section of solid argon has been measured for 0.5–3 MeV helium ions to an accuracy of not, vert, similar3%. The results agree within the experimental accuracies with our earlier measurements for gaseous argon over the energy region...

  6. Developments regarding the Bragg rule for stopping power and critical examination of its application to water

    International Nuclear Information System (INIS)

    Kamaratos, E.

    1983-01-01

    A critical comparison is made of various experimental findings regarding the Bragg additivity rule for stopping power. It appears that deviations from the Bragg additivity rule reported a long time ago and ascribed to chemical binding effects and phase effects are real, despite even recent statements of the contrary. Nevertheless, when the Bragg rule is applied to water, critical examination of very recent experimental results for the stopping power in the gaseous state of water, hydrogen and oxygen in this work suggest that the reported deviations from the Bragg additivity rule for the stopping power of gaseous water may be the result of experimental error. (orig.)

  7. Stopping powers for protons in materials of interest in dosimetry and in medical and biological applications

    International Nuclear Information System (INIS)

    Thwaites, D.I.

    1985-01-01

    Stopping powers are required for many radiation applications in medicine and biology. Their accuracy can be critical. Some published calculations for these situations have not included recent developments in stopping power theory or the body of work on deviations from additivity due to phase of chemical binding effects. These areas have recently been reviewed and mean excitation energies recommended for a range of materials of interest. Calculated stopping powers are presented for protons of 0.4 to 200 MeV taking the available information into account. The materials considered are Lucite, ICRU composition muscle and bone, A-150 plastic, a TE gas, acetylene and polystyrene and water and water vapour. With suitable corrections and suitable I values in the Bethe stopping power expression, accuracies of <2% can be achieved. (author)

  8. Consistent calculation of the stopping power for slow ions in two-dimensional electron gases

    International Nuclear Information System (INIS)

    Wang, You-Nian; Ma, Teng-Gai

    1997-01-01

    Within the framework of quantum scattering theory, we present a consistent calculation of the stopping power for slow protons and antiprotons moving in two-dimensional electron gases. The Friedel sum rule is used to determine the screening constant in the scattering potential. For the stopping power our results are compared with that of the random-phase approximation dielectric theory and that predicted by the linear Thomas-Fermi potential. copyright 1997 The American Physical Society

  9. Use of a range scaling method to determine alanine/water stopping power ratios

    International Nuclear Information System (INIS)

    McEwen, M.R.; Sephton, J.P.; Sharpe, P.H.G.; Shipley, D.R.

    2003-01-01

    A phantom composed of alanine dosimeter material has been constructed and depth-dose measurements made in a 10 MeV electron beam. The results have demonstrated the feasibility of using relative depth-dose measurements to determine stopping power ratios in materials of dosimetric interest. Experimental stopping power ratios for alanine dosimeter material and water agreed with the data of ICRU Report 37 within the uncertainty of the experiment (±1.2% at a 95% confidence level)

  10. Range and stopping power tables for 2.5-12MeV/nucleon heavy ions in solids

    International Nuclear Information System (INIS)

    Hubert, F.; Fleury, A.; Bimbot, R.; Gardes, D.

    1978-12-01

    A semi-empirical procedure to compute heavy ion stopping powers is presented. The calculations use recent stopping power values for alpha particles and a new parameterization for the effective charge taking into account the effect to the stopping medium. Stopping powers and ranges are tabulated for moving ions of atomic number 2<=Z<=45 in the energy region 2.5<=E/A<=12 MeV/nucleon for 18 solid materials

  11. Review of stopping power and Coulomb explosion for molecular ion in plasmas

    Directory of Open Access Journals (Sweden)

    Guiqiu Wang

    2018-03-01

    Full Text Available We summarize our theoretical studies for stopping power of energetic heavy ion, diatomic molecular ions and small clusters penetrating through plasmas. As a relevant research field for the heavy ion inertial confinement fusion (HICF, we lay the emphasis on the dynamic polarization and correlation effects of the constituent ion within the molecular ion and cluster for stopping power in order to disclose the role of the vicinage effect on the Coulomb explosion and energy deposition of molecules and clusters in plasma. On the other hand, as a promising scheme for ICF, both a strong laser field and an intense ion beam are used to irradiate a plasma target. So the influence of a strong laser field on stopping power is significant. We discussed a large range of laser and plasma parameters on the coulomb explosion and stopping power for correlated-ion cluster and C60 cluster. Furthermore, in order to indicate the effects of different cluster types and sizes on the stopping power, a comparison is made for hydrogen and carbon clusters. In addition, the deflection of molecular axis for diatomic molecules during the Coulomb explosion is also given for the cases both in the presence of a laser field and laser free. Finally, a future experimental scheme is put forward to measure molecular ion stopping power in plasmas in Xi'an Jiaotong University of China. Keywords: Molecules, Stopping power, Coulomb explosion, Vicinage effect, Laser, PACS Codes: 34.50.Bw, 52.40.Mj, 61.85.+p, 34.50.Dy

  12. Influence of H-C bonds on the stopping power of hard and soft carbonized layers

    International Nuclear Information System (INIS)

    Boutard, D.; Moeller, W.; Scherzer, B.M.U.

    1988-01-01

    Soft and hard carbon-hydrogen films were deposited in a rf glow discharge. Their stopping powers were deduced from depth-profile analysis by means of proton enhanced-cross-section scattering at around 1.5 MeV and 4 He + elastic-recoil detection at 2.6 MeV. In the case of soft films, ion-induced hydrogen depletion allowed study of the dependence of the stopping on hydrogen concentration. The presence of hydrogen increases the stopping power of the film by a factor of up to ∼2 compared to the predicted value for pure carbon. Moreover, Bragg's rule underestimates the total stopping considerably. However, good agreement is obtained with a recent theoretical model by Sabin et al. which takes into account the different C-C and C-H s

  13. Monte Carlo based water/medium stopping-power ratios for various ICRP and ICRU tissues

    International Nuclear Information System (INIS)

    Fernandez-Varea, Jose M; Carrasco, Pablo; Panettieri, Vanessa; Brualla, Lorenzo

    2007-01-01

    Water/medium stopping-power ratios, s w,m , have been calculated for several ICRP and ICRU tissues, namely adipose tissue, brain, cortical bone, liver, lung (deflated and inflated) and spongiosa. The considered clinical beams were 6 and 18 MV x-rays and the field size was 10 x 10 cm 2 . Fluence distributions were scored at a depth of 10 cm using the Monte Carlo code PENELOPE. The collision stopping powers for the studied tissues were evaluated employing the formalism of ICRU Report 37 (1984 Stopping Powers for Electrons and Positrons (Bethesda, MD: ICRU)). The Bragg-Gray values of s w,m calculated with these ingredients range from about 0.98 (adipose tissue) to nearly 1.14 (cortical bone), displaying a rather small variation with beam quality. Excellent agreement, to within 0.1%, is found with stopping-power ratios reported by Siebers et al (2000a Phys. Med. Biol. 45 983-95) for cortical bone, inflated lung and spongiosa. In the case of cortical bone, s w,m changes approximately 2% when either ICRP or ICRU compositions are adopted, whereas the stopping-power ratios of lung, brain and adipose tissue are less sensitive to the selected composition. The mass density of lung also influences the calculated values of s w,m , reducing them by around 1% (6 MV) and 2% (18 MV) when going from deflated to inflated lung

  14. Range-energy relations and stopping powers of organic liquids and vapours for alpha particles

    International Nuclear Information System (INIS)

    Akhavan-Rezayat, A.; Palmer, R.B.J.

    1980-01-01

    Experimental range-energy relations are presented for alpha particles in methyl alcohol, propyl alcohol, dichloromethane, chloroform and carbon tetrachloride in both the liquid and vapour phases. Stopping power values for these materials and for oxygen gas over the energy range 1.0-8.0 MeV are also given. From these results stopping powers have been derived for the -CH 2 -group and for -Cl occurring in chemical combination in the liquid and vapour phases. The molecular stopping power in the vapour phase is shown to exceed that in the liquid phase by 2-6% below 2 MeV, reducing to negligible differences at about 5 MeV for the materials directly investigated and for the -Cl atom. No significant phase effect is observed for the -CH 2 -group, but it is noted that the uncertainties in the values of the derived stopping powers are much greater in this case. Comparison of the experimental molecular stopping powers with values calculated from elemental values using the Bragg additivity rule shows agreement for vapours but not for liquids. (author)

  15. Electronic stopping power of polymers for heavy ions in the ion energy domain of LSS theory

    Energy Technology Data Exchange (ETDEWEB)

    Neetu [Department of Physics, Kurukshetra University, Kurukshetra 136 119, Haryana (India)], E-mail: neetuphy@gmail.com; Pratibha [Department of Physics, Kurukshetra University, Kurukshetra 136 119, Haryana (India); Sharma, V. [Department of Physics, Lovely Professional University, Phagwara 144 402 (India); Diwan, P.K. [Department of Physics, U.I.E.T., Kurukshetra University, Kurukshetra 136119, Haryana (India); Kumar, Shyam [Department of Physics, Kurukshetra University, Kurukshetra 136 119, Haryana (India)

    2009-04-15

    LSS based computed electronic stopping power values have been compared with the corresponding measured values in polymers for heavy ions with Z = 5-29, in the reduced ion velocity region, v{sub red} {<=} 1. Except for limited v{sub red} {approx} 0.6-0.85, the formulation generally shows significantly large deviations with the measured values. The {zeta} factor, which was approximated to be {approx}Z{sub 1}{sup 1/6}, involved in LSS theory has been suitably modified in the light of the available experimental stopping power data. The calculated stopping power values after incorporating modified {zeta} in LSS formula have been found to be in close agreement with measured values in various polymers in the reduced ion velocity range 0.35 {<=} v{sub red} {<=} 1.0.

  16. Electronic stopping power of polymers for heavy ions in the ion energy domain of LSS theory

    International Nuclear Information System (INIS)

    Neetu; Pratibha; Sharma, V.; Diwan, P.K.; Kumar, Shyam

    2009-01-01

    LSS based computed electronic stopping power values have been compared with the corresponding measured values in polymers for heavy ions with Z = 5-29, in the reduced ion velocity region, v red ≤ 1. Except for limited v red ∼ 0.6-0.85, the formulation generally shows significantly large deviations with the measured values. The ζ factor, which was approximated to be ∼Z 1 1/6 , involved in LSS theory has been suitably modified in the light of the available experimental stopping power data. The calculated stopping power values after incorporating modified ζ in LSS formula have been found to be in close agreement with measured values in various polymers in the reduced ion velocity range 0.35 ≤ v red ≤ 1.0.

  17. Direction-dependent stopping power and beam deflection in anisotropic solids

    International Nuclear Information System (INIS)

    Crawford, O.H.

    1989-01-01

    Directional effects on the motion of swift ions in anisotropic media are studied. The stopping power is a function of the direction of the velocity relative to the principle axes of the medium, and there is a nonzero lateral force on the ion tending to bend its trajectory. These effects arise from the anisotropy of the dielectric response, and are distinct from channeling. Simple expressions are derived for the stopping power and lateral force in the nonrelativistic high-velocity limit, and calculations are performed for crystalline graphite. 6 refs., 7 figs

  18. Analytic formula of stopping power for high energy electrons in liquid media

    International Nuclear Information System (INIS)

    Scarlat, F.; Niculescu, V.I.R.

    1994-01-01

    This article is part of a series on the calculation of high energy electron dose using multiple scattering theory. In the current article we present an analytic formula obtained for the collision stopping power (S/ρ) c and the radiative stopping power (S/ρ) r for electrons with energy within 1 MeV - 35 MeV range. For that purpose we used data given for electrons in water in NBS-IR-2550A. The analytical formulae are approximating the data calculated by Berger and Seltzer within 1-2% limit. (Author)

  19. Heavy-ion stopping powers and the low-velocity-projectile z3 effect

    International Nuclear Information System (INIS)

    Porter, L.E.

    1977-01-01

    Recent heavy-ion stopping-power measurements with elemental solid targets have been analyzed in order to ascertain the influence on effective ion charge of incorporating the low-velocity-projectile z 3 effect in Bethe-Bloch calculations. Shell corrections and the mean excitation energy of a given target were held fixed while searching for the best-fit value of a single charge-state parameter. In general, excellent fits to the stopping powers at projectile energies above 0.3 MeV/amu were achieved. Results of the present study compare very favorably with those from other extant methods of analysis

  20. Stopping power of antiprotons in H, H2, and He targets

    DEFF Research Database (Denmark)

    Lühr, Armin Christian; Saenz, Alejandro

    2009-01-01

    The stopping power of antiprotons in atomic and molecular hydrogen as well as helium was calculated in an impact-energy range from 1 keV to 6.4 MeV. In the case of H2 and He the targets were described with a single-active electron model centered on the target. The collision process was treated...... of the corrections to the first-order stopping number, the average energy transferred to the target electrons, and the relative importance of the excitation and the ionization process for the energy loss of the projectile was determined. Finally, the stopping powers of the H, H2, and He targets were directly...

  1. Electronic stopping powers for fluorine ions in 19F+-implanted silver gallium diselenide

    International Nuclear Information System (INIS)

    Liu Xiangdong; Xia Yueyuan; Li Feng; Lu Qingming; Huang Boda

    2004-01-01

    Electronic stopping powers for 80-350 keV 19 F ions in AgGaSe 2 were obtained by range measurement. Depth profiles of 19 F in AgGaSe 2 were measured by using the 19 F(p,αγ) 16 O resonant nuclear reaction at E R =872.1 keV. A proper convolution calculation method was used to extract the true distribution of fluorine from the experimental excitation yield curves. The electronic stopping powers were derived through fitting the projected range distributions, simulated by using the TRIM/XLL code, to the experimentally measured range distributions. The electronic stopping cross-sections were compared with those obtained from Monte Carlo simulation codes

  2. Electronic stopping powers for fluorine ions in {sup 19}F{sup +}-implanted silver gallium diselenide

    Energy Technology Data Exchange (ETDEWEB)

    Liu Xiangdong E-mail: xdliu@sdu.edu.cn; Xia Yueyuan; Li Feng; Lu Qingming; Huang Boda

    2004-08-01

    Electronic stopping powers for 80-350 keV {sup 19}F ions in AgGaSe{sub 2} were obtained by range measurement. Depth profiles of {sup 19}F in AgGaSe{sub 2} were measured by using the {sup 19}F(p,{alpha}{gamma}){sup 16}O resonant nuclear reaction at E{sub R}=872.1 keV. A proper convolution calculation method was used to extract the true distribution of fluorine from the experimental excitation yield curves. The electronic stopping powers were derived through fitting the projected range distributions, simulated by using the TRIM/XLL code, to the experimentally measured range distributions. The electronic stopping cross-sections were compared with those obtained from Monte Carlo simulation codes.

  3. Interaction of heavy ion beams with a hydrogen plasma: plasma lens effect and stopping power enhancement

    International Nuclear Information System (INIS)

    Gardes, D.; Bimbot, R.; Della-Negra, S.; Dumail, M.; Kubica, B.; Richard, A.; Rivet, M.F.; Servajean, A.; Deutsch, C.; Maynard, G.

    1988-01-01

    By coupling a hydrogen plasma to a Tandem accelerator, transmission and energy losses of 2 MeV/u carbon and sulfur beams passing through a plasma target have been investigated. Fluctuations in beam transmission have been observed and attributed to a plasma lens effect. Moreover, energy loss measurements indicate an enhanced stopping power of the plasma relative to its cold matter equivalent

  4. Stopping Power and Energy Straggling of Channeled He-Ions in GaN

    International Nuclear Information System (INIS)

    Turos, A.; Ratajczak, R.; Pagowska, K.; Nowicki, L.; Stonert, A.; Caban, P.

    2011-01-01

    GaN epitaxial layers are usually grown on sapphire substrates. To avoid disastrous effect of the large lattice mismatch a thin polycrystalline nucleation layer is grown at 500 o C followed by the deposition of thick GaN template at much higher temperature. Remnants of the nucleation layer were visualized by transmission electron microscopy as defect agglomeration at the GaN/sapphire interface and provide a very useful depth marker for the measurement of channeled ions stopping power. Random and aligned spectra of He ions incident at energies ranging from 1.7 to 3.7 MeV have been measured and evaluated using the Monte Carlo simulation code McChasy. Impact parameter dependent stopping power has been calculated for channeling direction and its parameters have been adjusted according to experimental data. For virgin, i.e. as grown, samples, the ratio of channeled to random stopping power is constant and amounts to 0.7 in the energy range studied. Defects produced by ion implantation largely influence the stopping power. For channeled ions the variety of possible trajectories leads to different energy loss at a given depth, thus resulting in much larger energy straggling than that for the random path. Beam energy distributions at different depths have been calculated using the McChasy code. They are significantly broader than those predicted by the Bohr formula for random direction. (author)

  5. Power in discursive practices: The case of the STOP EPAs campaign

    NARCIS (Netherlands)

    Del Felice, M.C.

    2014-01-01

    Transnational activism has increased in relation to international trade and development politics in the past decades, yet their power has been inadequately studied. This article analyses the STOP EPAs campaign (2004-2009) which aimed to influence the negotiations of Economic Partnership Agreements

  6. Stopping powers of gases for ions of energy below 200 keV

    International Nuclear Information System (INIS)

    Fukuda, Akira

    1978-01-01

    There has been renewed interest in the stopping power of matters for ions in low energy region. But there is not an established theory in this energy region, and experimental data did not coincide with the curves in some data books. Therefore, precise experimental measurement is still necessary. In present neutron dosimetry, tissues are the object of measurement of absorbed dose. In this experiment, it was intended to use tissue equivalent gas as a target gas. In the experimental apparatus, ions come from the Cockcroft-Walton accelerator are applied to the cell, in which the target gas is admitted from gas source. Gas in the cell is observed with the electrostatic energy analyzer. Stopping power is calculated from the results of energy loss measurement. In this report, only the preliminary results are shown. The tissue equivalent gas is composed of CH 4 , CO 2 and N 2 , each percentage is 64.95, 32.2 and 2.85, respectively. It seems that the stopping powers of noble gases will be useful for the developments of the theory, and the stopping power for He + ions was measured. The results are shown in a figure, and the errors were estimated to be less than 1.5%. At the end of the report, some discussions among a few persons are added. (Wakatsuki, Y.)

  7. Inventory of nuclear power plants and research reactors temporary or definitively stopped in industrialized countries

    International Nuclear Information System (INIS)

    Clauzon, J.; Vaubert, B.

    1984-12-01

    This paper presents data and information on the end of the life of nuclear reactors. One deals more particularly with installations of industrialized countries. This report gives the motivations which have involved the definitive shut down of nuclear power plants and of research reactors in the concerned countries. A schedule of definitive reactor shutdowns is presented. Then, one deals with nuclear power plants of which the construction has been stopped. The reasons of these situations are also given. The temporary difficulties met during the construction or the starting of nuclear power plants these last years are mentioned. Most times, there are economical or political considerations, or safety reasons. Finally, the nuclear power plants stopped for more than two years are mentioned [fr

  8. Simple polynomial approximation to modified Bethe formula low-energy electron stopping powers data

    Energy Technology Data Exchange (ETDEWEB)

    Taborda, A., E-mail: ana.taborda@irsn.fr [Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-HOM/SDI/LEDI, BP-17, 92262 Fontenay-aux-Roses (France); Desbrée, A. [Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-HOM/SDI/LEDI, BP-17, 92262 Fontenay-aux-Roses (France); Reis, M.A. [C" 2TN, Campus Tecnológico e Nuclear, Instituto Superior Técnico, Universidade de Lisboa, EN10 km139.7, 2685-066 Bobadela LRS (Portugal)

    2015-08-01

    A recently published detailed and exhaustive paper on cross-sections for ionisation induced by keV electrons clearly shows that electron phenomena occurring in parallel with X-ray processes may have been dramatically overlooked for many years, mainly when low atomic number species are involved since, in these cases, the fluorescence coefficient is smaller than the Auger yield. An immediate problem is encountered while attempting to tackle the issue. Accounting for electron phenomena requires the knowledge of the stopping power of electrons within, at least, a reasonably small error. Still, the Bethe formula for stopping powers is known to not be valid for electron energies below 30 keV, and its use leads to values far off experimental ones. Recently, a few authors have addressed this problem and both detailed tables of electron stopping powers for various atomic species and attempts to simplify the calculations, have emerged. Nevertheless, its implementation in software routines to efficiently calculate keV electron effects in materials quickly becomes a bit cumbersome. Following a procedure already used to establish efficient methods to calculate ionisation cross-sections by protons and alpha particles, it became clear that a simple polynomial approximation could be set, which allows retrieving the electronic stopping powers with errors of less than 20% for energies above 500 eV and less than 50% for energies between 50 eV and 500 eV. In this work, we present this approximation which, based on just six parameters, allows to recover electron stopping power values that are less than 20% different from recently published experimentally validated tabulated data.

  9. Stopping Power of Be, Al, Cu, Ag, Pt, and Au for 5-12-MeV Protons and Deuterons

    DEFF Research Database (Denmark)

    Andersen, H.H.; Hanke, C.; Sørensen, H.

    1967-01-01

    Recent measurements on stopping power of aluminum have been continued with the stopping materials Be, Cu, Ag, Pt, and Au. The method of measuring stopping powers utilizing a thermometric compensation technique working at liquid-helium temperature has been used. Results are obtained with a standard...... deviation of 0.3%, and agree with other published experimental results and with Bichsel's tabulated values within their stated errors....

  10. Measuring the stopping power of α particles in compact bone for BNCT

    Science.gov (United States)

    Provenzano, L.; Rodríguez, L. M.; Fregenal, D.; Bernardi, G.; Olivares, C.; Altieri, S.; Bortolussi, S.; González, S. J.

    2015-01-01

    The stopping power of α particles in thin films of decalcified sheep femur, in the range of 1.5 to 5.0 MeV incident energy, was measured by transmission of a backscattered beam from a heavy target. Additionally, the film elemental composition was determined by Rutherford Backscattering Spectrometry (RBS). These data will be used to measure boron concentration in thin films of bone using a spectrometry technique developed by the University of Pavia, since the concentration ratio between healthy tissue and tumor is of fundamental importance in Boron Neutron Capture Therapy (BNCT). The present experimental data are compared with numerical simulation results and with tabulated stopping power data of non-decalcified human bone.

  11. Ab initio research of stopping power for energetic ions in solids

    Energy Technology Data Exchange (ETDEWEB)

    He, Bin, E-mail: hebin-rc@163.com; Meng, Xu-Jun; Wang, Jian-Guo

    2017-03-01

    A new physical scenario is suggested to estimate the stopping power of energetic α particles in solid-density Be, Na, and Al at room temperature in an ab initio way based on the average atom model. In the scenario the stopping power is caused by the transition of free electrons to higher energy states and the ionization of bound electrons of the atom. Our results are found generally in good agreement with the recommended data in Al, Be and Na as well as the experimental data in Al. A comparison of energy loss with the recent experiment of protons in Be indicates that the scenario is more reasonable than the local density approximation in this case.

  12. Calculation of the stopping power and the path of charged particles in matter. Application example

    International Nuclear Information System (INIS)

    Barre, Bertrand; Du Lieu, Pierre

    1969-05-01

    The path of a charged particle in matter is calculated by integrating the stopping power of the medium against this particle. Depending on the energy of the particle, stopping powers are calculated using Lindhard, Bethe, or semi-empirical smoothing solutions. After exposing recent theories in this field, the authors present a Fortran subroutine which performs these various operations, and covers all energy domains. This routine is available for operation on IBM 360; it uses a magnetic tape library that can take into account experimental results. The subprogram presentation, leaving the user the option of entering the data and using the results at his discretion, allows a particularly flexible use. At the end of this note, some considerations on possible further improvements in the program, and a bibliography of the articles that have dealt with the question from a theoretical or an experimental point of view are discussed [fr

  13. The Barkas effect and other higher-order Z1-contributions to the stopping power

    International Nuclear Information System (INIS)

    Andersen, H.H.

    1985-01-01

    The experimental evidence for contributions to the stopping power proportional to Z 1 3 (Barkas effect) and Z 1 4 (Bloch correction) at velocities around 10 v 0 is reviewed. Quantitative evidence is found for both terms but it is not possible experimentally to discern whether hard collisions contribute to the Barkas term. Evidence from single-collision events are drawn into the discussion and some experiments which may turn out to be decisive are discussed. (orig.)

  14. Stopping-power and mass energy-absorption coefficient ratios for Solid Water

    International Nuclear Information System (INIS)

    Ho, A.K.; Paliwal, B.R.

    1986-01-01

    The AAPM Task Group 21 protocol provides tables of ratios of average restricted stopping powers and ratios of mean energy-absorption coefficients for different materials. These values were based on the work of Cunningham and Schulz. We have calculated these quantities for Solid Water (manufactured by RMI), using the same x-ray spectra and method as that used by Cunningham and Schulz. These values should be useful to people who are using Solid Water for high-energy photon calibration

  15. Ion energy loss at maximum stopping power in a laser-generated plasma

    International Nuclear Information System (INIS)

    Cayzac, W.

    2013-01-01

    In the frame of this thesis, a new experimental setup for the measurement of the energy loss of carbon ions at maximum stopping power in a hot laser-generated plasma has been developed and successfully tested. In this parameter range where the projectile velocity is of the same order of magnitude as the thermal velocity of the plasma free electrons, large uncertainties of up to 50% are present in the stopping-power description. To date, no experimental data are available to perform a theory benchmarking. Testing the different stopping theories is yet essential for inertial confinement fusion and in particular for the understanding of the alpha-particle heating of the thermonuclear fuel. Here, for the first time, precise measurements were carried out in a reproducible and entirely characterized beam-plasma configuration. It involved a nearly fully-stripped ion beam probing a homogeneous fully-ionized plasma. This plasma was generated by irradiating a thin carbon foil with two high-energy laser beams and features a maximum electron temperature of 200 eV. The plasma conditions were simulated with a two-dimensional radiative hydrodynamic code, while the ion-beam charge-state distribution was predicted by means of a Monte-Carlo code describing the charge-exchange processes of projectile ions in plasma. To probe at maximum stopping power, high-frequency pulsed ion bunches were decelerated to an energy of 0.5 MeV per nucleon. The ion energy loss was determined by a time-of-flight measurement using a specifically developed chemical-vapor-deposition diamond detector that was screened against any plasma radiation. A first experimental campaign was carried out using this newly developed platform, in which a precision better than 200 keV on the energy loss was reached. This allowed, via the knowledge of the plasma and of the beam parameters, to reliably test several stopping theories, either based on perturbation theory or on a nonlinear T-Matrix formalism. A preliminary

  16. Stopping power and range relations for low and high Z ions in solids: a critical analysis

    International Nuclear Information System (INIS)

    Virk, H.S.; Randhawa, G.S.

    1997-01-01

    A critical analysis of various stopping power and range formulations has been made by comparing the calculated stopping power and range values with corresponding experimental values for different low Z (1≤Z≤8) and high Z projectiles (54≤Z≤92) in different targets, e.g. Be, C, Al, Au, Pb, CR-39, Lexan, Mylar, LR-115, CH, (CH)n, TRIFOL-TN, etc. atvarious low and high energies. A comparative study has been made by taking into consideration different target and projectile combinations, e.g., heavy ion-light target, light ion-heavy target and light ion -light target etc., Overall the Ziegler formulation (TRIM-95) provides the best agreement with the experimental results for all projectile and target combinations except for heavy ion-light target combination where it underestimates the stopping power data and overestimates the range data in the range, 2-50 MeV/u. Mukherjee and Nayak formulation totally fails at relativistic and low energies of the projectile, irrespective of the projectile-target combination. Northcliffe and Schilling formulation does not show any particular trend. Benton and Henke formulation gives good agreement between experimental and theoretical data within the range of experimental errors. (orig.)

  17. The measurement of proton stopping power using proton-cone-beam computed tomography

    International Nuclear Information System (INIS)

    Zygmanski, P.; Rabin, M.S.Z.; Gall, K.P.; Rosenthal, S.J.

    2000-01-01

    A cone-beam computed tomography (CT) system utilizing a proton beam has been developed and tested. The cone beam is produced by scattering a 160 MeV proton beam with a modifier that results in a signal in the detector system, which decreases monotonically with depth in the medium. The detector system consists of a Gd 2 O 2 S:Tb intensifying screen viewed by a cooled CCD camera. The Feldkamp-Davis-Kress cone-beam reconstruction algorithm is applied to the projection data to obtain the CT voxel data representing proton stopping power. The system described is capable of reconstructing data over a 16x16x16cm 3 volume into 512x512x512 voxels. A spatial and contrast resolution phantom was scanned to determine the performance of the system. Spatial resolution is significantly degraded by multiple Coulomb scattering effects. Comparison of the reconstructed proton CT values with x-ray CT derived proton stopping powers shows that there may be some advantage to obtaining stopping powers directly with proton CT. The system described suggests a possible practical method of obtaining this measurement in vivo. (author)

  18. Examining real-time time-dependent density functional theory nonequilibrium simulations for the calculation of electronic stopping power

    Science.gov (United States)

    Yost, Dillon C.; Yao, Yi; Kanai, Yosuke

    2017-09-01

    In ion irradiation processes, electronic stopping power describes the energy transfer rate from the irradiating ion to the target material's electrons. Due to the scarcity and significant uncertainties in experimental electronic stopping power data for materials beyond simple solids, there has been growing interest in the use of first-principles theory for calculating electronic stopping power. In recent years, advances in high-performance computing have opened the door to fully first-principles nonequilibrium simulations based on real-time time-dependent density functional theory (RT-TDDFT). While it has been demonstrated that the RT-TDDFT approach is capable of predicting electronic stopping power for a wide range of condensed matter systems, there has yet to be an exhaustive examination of the physical and numerical approximations involved and their effects on the calculated stopping power. We discuss the results of such a study for crystalline silicon with protons as irradiating ions. We examine the influences of key approximations in RT-TDDFT nonequilibrium simulations on the calculated electronic stopping power, including approximations related to basis sets, finite size effects, exchange-correlation approximation, pseudopotentials, and more. Finally, we propose a simple and efficient correction scheme to account for the contribution from core-electron excitations to the stopping power, as it was found to be significant for large proton velocities.

  19. 78 FR 15714 - Welch Motel, Inc., Welch Oil, Inc., Boondocks USA Truck Stop, Bob Welch v. Midland Power...

    Science.gov (United States)

    2013-03-12

    ..., Inc., Welch Oil, Inc., Boondocks USA Truck Stop, Bob Welch v. Midland Power Cooperative, Corn Belt..., Welch Motel, Inc., Welch Oil, Inc., Boondocks USA Truck Stop, and Bob Welch (collectively, Complainants... into a contract to consume all of the electric energy and capacity generated by [[Page 15715...

  20. Evidences of the influence of the electronic stopping power in the elastic energy loss in thin films of amorphous carbon

    International Nuclear Information System (INIS)

    Grande, P.L.; Fichtner, P.F.P.; Behar, M.; Zawislak, E.F.C.

    1988-01-01

    Measurements of deepness of implanted ions in carbon films, show the possibility that the energy elastic component given to the medium, could be affected by the ineslastic stopping parcel, which could cause a total stopping power, smaller than the expected. (A.C.A.S.) [pt

  1. The stopping power and energy straggling of heavy ions in silicon nitride and polypropylene

    Energy Technology Data Exchange (ETDEWEB)

    Mikšová, R., E-mail: miksova@ujf.cas.cz [Nuclear Physics Institute of the Academy of Science of the Czech Republic v.v. i., 250 68 Rez (Czech Republic); Department of Physics, Faculty of Science, J. E. Purkinje University, Ceske Mladeze 8, 400 96 Usti nad Labem (Czech Republic); Hnatowicz, V. [Nuclear Physics Institute of the Academy of Science of the Czech Republic v.v. i., 250 68 Rez (Czech Republic); Macková, A.; Malinský, P. [Nuclear Physics Institute of the Academy of Science of the Czech Republic v.v. i., 250 68 Rez (Czech Republic); Department of Physics, Faculty of Science, J. E. Purkinje University, Ceske Mladeze 8, 400 96 Usti nad Labem (Czech Republic); Slepička, P. [Department of Solid State Engineering, Institute of Chemical Technology, 166 28 Prague (Czech Republic)

    2015-07-01

    The stopping power and energy straggling of {sup 12}C{sup 3+} and {sup 16}O{sup 3+} ions with energies between 4.5 and 7.8 MeV in a 0.166-μm-thin silicon nitride and in 4-μm-thin polypropylene foils were measured by means of an indirect transmission method using a half-covered PIPS detector. Ions scattered from a thin gold layer under a scattering angle of 150° were used. The energy spectra of back-scattered and decelerated ions were registered and evaluated simultaneously. The measured stopping powers were compared with the theoretical predictions simulated by SRIM-2008 and MSTAR codes. SRIM prediction of energy stopping is reasonably close to the experimentally obtained values comparing to MSTAR values. Better agreement between experimental and predicted data was observed for C{sup 3+} ion energy losses comparing to O{sup 3+} ions. The experimental data from Paul’s database and our previous experimental data were also discussed. The obtained experimental energy-straggling data were compared to those calculated by using Bohr’s, Yang’s models etc. The predictions by Yang are in good agreement with our experiment within a frame of uncertainty of 25%.

  2. The stopping power and energy straggling of heavy ions in silicon nitride and polypropylene

    International Nuclear Information System (INIS)

    Mikšová, R.; Hnatowicz, V.; Macková, A.; Malinský, P.; Slepička, P.

    2015-01-01

    The stopping power and energy straggling of 12 C 3+ and 16 O 3+ ions with energies between 4.5 and 7.8 MeV in a 0.166-μm-thin silicon nitride and in 4-μm-thin polypropylene foils were measured by means of an indirect transmission method using a half-covered PIPS detector. Ions scattered from a thin gold layer under a scattering angle of 150° were used. The energy spectra of back-scattered and decelerated ions were registered and evaluated simultaneously. The measured stopping powers were compared with the theoretical predictions simulated by SRIM-2008 and MSTAR codes. SRIM prediction of energy stopping is reasonably close to the experimentally obtained values comparing to MSTAR values. Better agreement between experimental and predicted data was observed for C 3+ ion energy losses comparing to O 3+ ions. The experimental data from Paul’s database and our previous experimental data were also discussed. The obtained experimental energy-straggling data were compared to those calculated by using Bohr’s, Yang’s models etc. The predictions by Yang are in good agreement with our experiment within a frame of uncertainty of 25%

  3. Reaction-in-flight neutrons as a test of stopping power in degenerate plasmas

    Science.gov (United States)

    Hayes, A. C.; Jungman, Gerard; Schulz, A. E.; Boswell, M.; Fowler, M. M.; Grim, G.; Klein, A.; Rundberg, R. S.; Wilhelmy, J. B.; Wilson, D.; Cerjan, C.; Schneider, D.; Sepke, S. M.; Tonchev, A.; Yeamans, C.

    2015-08-01

    We present the first measurements of reaction-in-flight (RIF) neutrons in an inertial confinement fusion system. The experiments were carried out at the National Ignition Facility, using both Low Foot and High Foot drives and cryogenic plastic capsules. In both cases, the high-energy RIF ( En> 15 MeV) component of the neutron spectrum was found to be about 10-4 of the total. The majority of the RIF neutrons were produced in the dense cold fuel surrounding the burning hotspot of the capsule, and the data are consistent with a compressed cold fuel that is moderately to strongly coupled (Γ˜ 0.6) and electron degenerate (θFermi/θe˜ 4). The production of RIF neutrons is controlled by the stopping power in the plasma. Thus, the current RIF measurements provide a unique test of stopping power models in an experimentally unexplored plasma regime. We find that the measured RIF data strongly constrain stopping models in warm dense plasma conditions, and some models are ruled out by our analysis of these experiments.

  4. Stopping power and polarization induced in a plasma by a fast charged particle in circular motion

    Energy Technology Data Exchange (ETDEWEB)

    Villo-Perez, Isidro [Departamento de Electronica, Tecnologia de las Computadoras y Proyectos, Universidad Politecnica de Cartagena, Cartagena (Spain); Arista, Nestor R. [Division Colisiones Atomicas, Centro Atomico Bariloche and Instituto Balseiro, Comision Nacional de Energia Atomica, Bariloche (Argentina); Garcia-Molina, Rafael [Departamento de Fisica, Universidad de Murcia, Murcia (Spain)

    2002-03-28

    We describe the perturbation induced in a plasma by a charged particle in circular motion, analysing in detail the evolution of the induced charge, the electrostatic potential and the energy loss of the particle. We describe the initial transitory behaviour and the different ways in which convergence to final stationary solutions may be obtained depending on the basic parameters of the problem. The results for the stopping power show a resonant behaviour which may give place to large stopping enhancement values as compared with the case of particles in straight-line motion with the same linear velocity. The results also explain a resonant effect recently obtained for particles in circular motion in magnetized plasmas. (author)

  5. Ab initio approach to the ion stopping power at the plasma-solid interface

    Science.gov (United States)

    Bonitz, Michael; Schlünzen, Niclas; Wulff, Lasse; Joost, Jan-Philip; Balzer, Karsten

    2016-10-01

    The energy loss of ions in solids is of key relevance for many applications of plasmas, ranging from plasma technology to fusion. Standard approaches are based on density functional theory or SRIM simulations, however, the applicability range and accuracy of these results are difficult to assess, in particular, for low energies. Here we present an independent approach that is based on ab initio nonequilibrium Green functions theory, e.g. that allows to incorporate electronic correlations effects of the solid. We present the first application of this method to low-temperature plasmas, concentrating on proton and alpha-particle stopping in a graphene layer. In addition to the stopping power we present time-dependent results for the local electron density, the spectral function and the photoemission spectrum that is directly accessible in optical, UV or x-ray diagnostics. http://www.itap.uni-kiel.de/theo-physik/bonitz/.

  6. Improvements in the stopping power library libdEdx and release of the web GUI dedx.au.dk

    International Nuclear Information System (INIS)

    Toftegaard, J; Lühr, A; Bassler, N; Sobolevsky, N

    2014-01-01

    Purpose: In ion beam therapy electronic stopping power data enter in different disciplines, e.g., dose planning, dosimetry, and radiobiology. However, relevant stopping power data are only known within an accuracy of 2%-10%. We started the software library project libdEdx to unify data from several well-known stopping power sources into one ready-to-use package being 1) freely available and 2) easy accessible via a web-based front end. Methods: Currently, stopping power data from PSTAR, ASTAR, MSTAR and ICRU49+73 are implemented along with a version of the Bethe formula. The library is programmed in the language C to provide broad portability and high performance. A clean API provides full access to the underlying functions and thread safety in multi-threaded applications. The possibility to define arbitrary materials complements the list of predefined ICRU materials. Furthermore, we introduced a collection of tools, e.g., inverse stopping power look-up as well as CSDA range calculation and its inverse. Results: On a standard desktop PC libdEdx calculates 22 million look-ups/sec. A web GUI (available at http://dedx.au.dk) provides easy access to libdEdx and download of stopping data and graphs. For compounds, we observe that stopping power data are robust for variations in the mean excitation potential of the constituents as long as the total mean excitation potential is fixated. Conclusion: We released libdEdx (version number 1.2.1: http://sf.net/projects/libdedx/) with a web-based GUI. Future development will focus on implementing further stopping powers sources (e.g., for electrons and nuclear stopping) and relativistic effects.

  7. Measurement of stopping powers of gases for heavy ions of 3 to 13 MeV by nucleon

    International Nuclear Information System (INIS)

    Orliange, I.

    1985-09-01

    The stopping powers of gases have been measured for incident 10 Ne, 18 Ar, 29 Cu, 36 Kr and 47 Ag ions of 3 to 13 MeV/u. These measurements have confirmed the existence of a gas-solid difference for the stopping powers (the stopping power of solids being larger than that of gazes). Such a difference was theoretically postulated by Bohr and Lindhard in 1954, and experimentally observed for the first time by Geissel in 1982. This effect can be qualitatively interpreted by a difference in the ion's effective charge in stopping power. However, the determination of charge state distribution for Ar and Fe ions in two particular cases (Ar + Nsub(2s)or Nsub(2g) and (Fe + Csub(s) or Csub(g)) from a theoric model and experimental cross sections for atomic collisions don't quantitatively account for observed differences [fr

  8. SU-G-TeP1-02: Analytical Stopping Power and Range Parameterization for Therapeutic Energy Intervals

    Energy Technology Data Exchange (ETDEWEB)

    Donahue, W [Louisiana State University, Baton Rouge, LA (United States); Newhauser, W [Louisiana State University, Baton Rouge, LA (United States); Mary Bird Perkins Cancer Center, Baton Rouge, LA (United States); Ziegler, J F [United States Naval Academy, Annapolis, MD (United States)

    2016-06-15

    Purpose: To develop a simple, analytic parameterization of stopping power and range, which covers a wide energy interval and is applicable to many species of projectile ions and target materials, with less than 15% disagreement in linear stopping power and 1 mm in range. Methods: The new parameterization was required to be analytically integrable from stopping power to range, and continuous across the range interval of 1 µm to 50 cm. The model parameters were determined from stopping power and range data for hydrogen, carbon, iron, and uranium ions incident on water, carbon, aluminum, lead and copper. Stopping power and range data was taken from SRIM. A stochastic minimization algorithm was used to find model parameters, with 10 data points per energy decade. Additionally, fitting was performed with 2 and 26 data points per energy decade to test the model’s robustness to sparse Results: 6 free parameters were sufficient to cover the therapeutic energy range for each projectile ion species (e.g. 1 keV – 300 MeV for protons). The model agrees with stopping power and range data well, with less than 9% relative stopping power difference and 0.5 mm difference in range. As few as, 4 bins per decade were required to achieve comparable fitting results to the full data set. Conclusion: This study successfully demonstrated that a simple analytic function can be used to fit the entire energy interval of therapeutic ion beams of hydrogen and heavier elements. Advantages of this model were the small number (6) of free parameters, and that the model calculates both stopping power and range. Applications of this model include GPU-based dose calculation algorithms and Monte Carlo simulations, where available memory is limited. This work was supported in part by a research agreement between United States Naval Academy and Louisiana State University: Contract No N00189-13-P-0786. In addition, this work was accepted for presentation at the American Nuclear Society Annual Meeting

  9. SU-G-TeP1-02: Analytical Stopping Power and Range Parameterization for Therapeutic Energy Intervals

    International Nuclear Information System (INIS)

    Donahue, W; Newhauser, W; Ziegler, J F

    2016-01-01

    Purpose: To develop a simple, analytic parameterization of stopping power and range, which covers a wide energy interval and is applicable to many species of projectile ions and target materials, with less than 15% disagreement in linear stopping power and 1 mm in range. Methods: The new parameterization was required to be analytically integrable from stopping power to range, and continuous across the range interval of 1 µm to 50 cm. The model parameters were determined from stopping power and range data for hydrogen, carbon, iron, and uranium ions incident on water, carbon, aluminum, lead and copper. Stopping power and range data was taken from SRIM. A stochastic minimization algorithm was used to find model parameters, with 10 data points per energy decade. Additionally, fitting was performed with 2 and 26 data points per energy decade to test the model’s robustness to sparse Results: 6 free parameters were sufficient to cover the therapeutic energy range for each projectile ion species (e.g. 1 keV – 300 MeV for protons). The model agrees with stopping power and range data well, with less than 9% relative stopping power difference and 0.5 mm difference in range. As few as, 4 bins per decade were required to achieve comparable fitting results to the full data set. Conclusion: This study successfully demonstrated that a simple analytic function can be used to fit the entire energy interval of therapeutic ion beams of hydrogen and heavier elements. Advantages of this model were the small number (6) of free parameters, and that the model calculates both stopping power and range. Applications of this model include GPU-based dose calculation algorithms and Monte Carlo simulations, where available memory is limited. This work was supported in part by a research agreement between United States Naval Academy and Louisiana State University: Contract No N00189-13-P-0786. In addition, this work was accepted for presentation at the American Nuclear Society Annual Meeting

  10. An apparatus to measure stopping powers for low-energy antiprotons and protons

    CERN Document Server

    Andersen, H H; Ichioka, T; Knudsen, H; Møller, S P; Uggerhøj, U

    2002-01-01

    One of the experiments to be performed under the ASACUSA collaboration at the CERN Antiproton Decelerator is a measurement of the energy loss of low energy antiprotons in thin foils. An electrostatic spectrometer has been developed for this task. We describe the design and initial tests of the apparatus with protons. By changing a high-voltage applied on the target the energy of the projectile ions at impact on the target can easily be varied. In this way we have measured the stopping-power and the energy-loss straggling for protons over a wide energy range to below one keV.

  11. Basic experimental preparation for the measurement of the stopping power of heavy ions in matter

    International Nuclear Information System (INIS)

    Carvalho Brito Brum, H. de.

    1976-02-01

    To measure the stopping power of heavy ions in solid matter one must develop both an experimental apparatus and a data analysis program. This thesis discusses these preparatory works and the methods to be employed. The design, building and testing of a scattering chamber with many detectors; the preparation of thin solid films, their analysis by electron diffraction and their thickness measurements; the testing of the electronic system; the calibration of the 4 MeV Van de Graaf accelerator at PUC/RJ; and the development of an original data analysis computer program are presented. (Author) [pt

  12. Quiet: The Power of Introvert in a World That Can’t Stop Talking

    OpenAIRE

    Sean Schat

    2012-01-01

    Do you pay attention to the differences between extroversion and introversion? It can be fascinating to consider who is and is not aware of  the distinction between the two, as well as the significant formative role they both play in daily perceptions and interactions.  In my experience, more often than not it is the introverts who recognize and appreciate the difference, while too many extroverts remain unaware. In  Quiet: The Power of Introverts in a World That Can’t Stop Talking(2012), Sus...

  13. High post-movement parietal low-beta power during rhythmic tapping facilitates performance in a stop task.

    Science.gov (United States)

    Fischer, Petra; Tan, Huiling; Pogosyan, Alek; Brown, Peter

    2016-09-01

    Voluntary movements are followed by a post-movement electroencephalography (EEG) beta rebound, which increases with practice and confidence in a task. We hypothesized that greater beta modulation reflects less load on cognitive resources and may thus be associated with faster reactions to new stimuli. EEG was recorded in 17 healthy subjects during rhythmically paced index finger tapping. In a STOP condition, participants had to interrupt the upcoming tap in response to an auditory cue, which was timed such that stopping was successful only in ~ 50% of all trials. In a second condition, participants carried on tapping twice after the stop signal (CONTINUE condition). Thus the conditions were distinct in whether abrupt stopping was required as a second task. Modulation of 12-20 Hz power over motor and parietal areas developed with time on each trial and more so in the CONTINUE condition. Reduced modulation in the STOP condition went along with reduced negative mean asynchronies suggesting less confident anticipation of the timing of the next tap. Yet participants were more likely to stop when beta modulation prior to the stop cue was more pronounced. In the STOP condition, expectancy of the stop signal may have increased cognitive load during movement execution given that the task might have to be stopped abruptly. However, within this condition, stopping ability was increased if the preceding tap was followed by a relatively larger beta increase. Significant, albeit weak, correlations confirmed that increased post-movement beta power was associated with faster reactions to new stimuli, consistent with reduced cognitive load. © 2016 The Authors. European Journal of Neuroscience published by Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  14. Simulations of the energy loss of ions at the stopping-power maximum in a laser-induced plasma

    International Nuclear Information System (INIS)

    Cayzac, W.; Malka, G.; Frank, A.; Bagnoud, V.; Blažević, A.; Schlegel, T.; Ortner, A.; Bedacht, S.; Deppert, O.; Knetsch, A.; Schaumann, G.; Wagner, F.; Basko, M.M.; Gericke, D.O.; Hallo, L.; Pépitone, K.; Kraus, D.; Schumacher, D.; Tauschwitz, An.; Vorberger, J.

    2016-01-01

    Simulations have been performed to study the energy loss of carbon ions in a hot, laser-generated plasma in the velocity region of the stopping-power maximum. In this parameter range, discrepancies of up to 30% exist between the various stopping theories and hardly any experimental data are available. The considered plasma, created by irradiating a thin carbon foil with two high-energy laser beams, is fully-ionized with a temperature of nearly 200 eV. To study the interaction at the maximum stopping power, Monte-Carlo calculations of the ion charge state in the plasma are carried out at a projectile energy of 0.5 MeV per nucleon. The predictions of various stopping-power theories are compared and experimental campaigns are planned for a first-time theory benchmarking in this low-velocity range. (paper)

  15. Starting and stopping control on power conditioner in photovoltaic power system; Taiyoko hatsuden system ni okeru power conditioner no kido teishi seigyo ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Hirose, M.; Ishihara, Y.; Todaka, T.; Harada, K. [Doshisha University, Kyoto (Japan); Oshiro, H.; Nakamura, H. [Japan Quality Assurance Organization, Tokyo (Japan)

    1997-11-25

    Studies are made about the control of the power conditioner over the maximum power point tracking (MPPT) function in a photovoltaic power generation system. The analysis is conducted by means of computer simulation into the effect of a start/stop function added to the control of MPPT and the effect on the generation of power of the setting of parameters in the start/stop function. The reduction in output power due to difference between the actual operation point and the optimum operation point is evaluated by use of a load matching correction factor. In this simulation, it is assumed that the solar cell array consists of 13 rows in 5 parallel columns, is capable of a normal output of 3.149kW, has a panel tilted at 30 degrees, and faces due south. The power conditioner is assumed to be a system rated at 3kVA, equipped with system interconnection and back flow features. As a result, it is learned that the stop voltage should be set at 180V or lower and the steady voltage near 185.5V for a good result and that there is not much need after all for the start/stop technique. 2 refs., 8 figs., 2 tabs.

  16. The stopping powers and energy straggling of heavy ions in polymer foils

    Energy Technology Data Exchange (ETDEWEB)

    Mikšová, R., E-mail: miksova@ujf.cas.cz [Nuclear Physics Institute of the Academy of Sciences of the Czech Republic, v.v.i., 250 68 Rez (Czech Republic); Department of Physics, Faculty of Science, J.E. Purkinje University, Ceske Mladeze 8, 400 96 Usti nad Labem (Czech Republic); Macková, A.; Malinský, P. [Nuclear Physics Institute of the Academy of Sciences of the Czech Republic, v.v.i., 250 68 Rez (Czech Republic); Department of Physics, Faculty of Science, J.E. Purkinje University, Ceske Mladeze 8, 400 96 Usti nad Labem (Czech Republic); Hnatowicz, V. [Nuclear Physics Institute of the Academy of Sciences of the Czech Republic, v.v.i., 250 68 Rez (Czech Republic); Slepička, P. [Department of Solid State Engineering, Institute of Chemical Technology, 166 28 Prague (Czech Republic)

    2014-07-15

    The stopping power and energy straggling of {sup 7}Li, {sup 12}C and {sup 16}O ions in thin poly(etheretherketone) (PEEK), polyethylene terephthalate (PET) and polycarbonate (PC) foils were measured in the incident beam energy range of 9.4–11.8 MeV using an indirect transmission method. Ions scattered from a thin gold target at an angle of 150° were registered by a partially depleted PIPS detector, partly shielded with a polymer foil placed in front of the detector. Therefore, the signals from both direct and slowed down ions were visible in the same energy spectrum, which was evaluated by the ITAP code, developed at our laboratory. The ITAP code was employed to perform a Gaussian-fitting procedure to provide a complete analysis of each measured spectrum. The measured stopping powers were compared with the predictions obtained from the SRIM-2008 and MSTAR codes and with previous experimental data. The energy straggling data were compared with those calculated by using Bohr’s, Lindhard–Scharff and Bethe–Livingston theories.

  17. The stopping powers and energy straggling of heavy ions in polymer foils

    International Nuclear Information System (INIS)

    Mikšová, R.; Macková, A.; Malinský, P.; Hnatowicz, V.; Slepička, P.

    2014-01-01

    The stopping power and energy straggling of 7 Li, 12 C and 16 O ions in thin poly(etheretherketone) (PEEK), polyethylene terephthalate (PET) and polycarbonate (PC) foils were measured in the incident beam energy range of 9.4–11.8 MeV using an indirect transmission method. Ions scattered from a thin gold target at an angle of 150° were registered by a partially depleted PIPS detector, partly shielded with a polymer foil placed in front of the detector. Therefore, the signals from both direct and slowed down ions were visible in the same energy spectrum, which was evaluated by the ITAP code, developed at our laboratory. The ITAP code was employed to perform a Gaussian-fitting procedure to provide a complete analysis of each measured spectrum. The measured stopping powers were compared with the predictions obtained from the SRIM-2008 and MSTAR codes and with previous experimental data. The energy straggling data were compared with those calculated by using Bohr’s, Lindhard–Scharff and Bethe–Livingston theories

  18. Secondary electrons as probe of preequilibrium stopping power of ions penetrating solids

    International Nuclear Information System (INIS)

    Kroneberger, K.; Rothard, H.; Koschar, P.; Lorenzen, P.; Groeneveld, K.O.; Clouvas, A.; Veje, E.; Kemmler, J.

    1990-01-01

    The passage of ions through solid media is accompanied by the emission of low energy secondary electrons. At high ion velocities v p (i.e. v p > 10 7 cm/s) the kinetic emission of electrons as a result of direct Coulomb interaction between the ion and the target electron is the dominant initial production mechanism. The energy lost by the ion and, thus, transferred to the electrons is known as electronic stopping power in the solid. Elastic and inelastic interactions of primary, liberated electrons on their way through the bulk and the surface of the solid modify strongly their original energy and angular distribution and, in particular, leads to the transfer of their energy to further, i.e. secondary electrons (SE), such that the main part of the deposited energy of the ion is eventually over transferred to SE. It is, therefore, suggestive to assume a proportionality between the electronic stopping power S sm-bullet of the ion and the total SE yield g, i.e. the number of electrons ejected per ion. Following Sternglass the authors consider schematically for kinetic SE emission contributions from two extreme cases: (a) SEs produced mostly isotropically with large impact parameter, associated with an escape depth L SE from the solid; (b) SEs produced mostly unisotropically in forward direction with small impact parameter (δ-electrons), associated with a transport length L δ

  19. A simulation study on proton computed tomography (CT) stopping power accuracy using dual energy CT scans as benchmark.

    Science.gov (United States)

    Hansen, David C; Seco, Joao; Sørensen, Thomas Sangild; Petersen, Jørgen Breede Baltzer; Wildberger, Joachim E; Verhaegen, Frank; Landry, Guillaume

    2015-01-01

    Accurate stopping power estimation is crucial for treatment planning in proton therapy, and the uncertainties in stopping power are currently the largest contributor to the employed dose margins. Dual energy x-ray computed tomography (CT) (clinically available) and proton CT (in development) have both been proposed as methods for obtaining patient stopping power maps. The purpose of this work was to assess the accuracy of proton CT using dual energy CT scans of phantoms to establish reference accuracy levels. A CT calibration phantom and an abdomen cross section phantom containing inserts were scanned with dual energy and single energy CT with a state-of-the-art dual energy CT scanner. Proton CT scans were simulated using Monte Carlo methods. The simulations followed the setup used in current prototype proton CT scanners and included realistic modeling of detectors and the corresponding noise characteristics. Stopping power maps were calculated for all three scans, and compared with the ground truth stopping power from the phantoms. Proton CT gave slightly better stopping power estimates than the dual energy CT method, with root mean square errors of 0.2% and 0.5% (for each phantom) compared to 0.5% and 0.9%. Single energy CT root mean square errors were 2.7% and 1.6%. Maximal errors for proton, dual energy and single energy CT were 0.51%, 1.7% and 7.4%, respectively. Better stopping power estimates could significantly reduce the range errors in proton therapy, but requires a large improvement in current methods which may be achievable with proton CT.

  20. Study of the stopping power and straggling for alpha particles and protons in organic solids, liquids and gases

    International Nuclear Information System (INIS)

    Haque, A.K.M.; Mohammadi, A.; Nikjoo, H.

    1985-01-01

    The stopping power and straggling for 5.5 MeV alpha particles in liquid and vapour phases of water, methanol, ethanol, propanol, h-hexane, n-octane and cyclohexane, and those for low energy protons in ethylene, styrene and propylene and their polymers, have been measured. Range-energy data have been fitted with inverse stopping power functions to give the cross sections. In each case, five parameters have been adjusted to obtain the best fit. The value of chi-squared per degree of freedom has been calculated, together with the parameters. The theoretical stopping cross section has been considered employing the Bethe-Bloch expression together with various corrections (shell correction using Walske and Bichsel procedure, Z 1 3 contribution according to Ashley and Bloch correction based on Lindhard formalism). The existence of a phase effect has been clearly demonstrated for the stopping of both alpha particles and protons. (author)

  1. Resonant charging and stopping power of slow channelling atoms in a crystalline metal

    International Nuclear Information System (INIS)

    Mason, D R; Race, C P; Foo, M H F; Horsfield, A P; Foulkes, W M C; Sutton, A P

    2012-01-01

    Fast moving ions travel great distances along channels between low-index crystallographic planes, slowing through collisions with electrons, until finally they hit a host atom initiating a cascade of atomic displacements. Statistical penetration ranges of incident particles are reliably used in ion-implantation technologies, but a full, necessarily quantum-mechanical, description of the stopping of slow, heavy ions is challenging and the results of experimental investigations are not fully understood. Using a self-consistent model of the electronic structure of a metal, and explicit treatment of atomic structure, we find by direct simulation a resonant accumulation of charge on a channelling ion analogous to the Okorokov effect but originating in electronic excitation between delocalized and localized valence states on the channelling ion and its transient host neighbours, stimulated by the time-periodic potential experienced by the channelling ion. The charge resonance reduces the electronic stopping power on the channelling ion. These are surprising and interesting new chemical aspects of channelling, which cannot be predicted within the standard framework of ions travelling through homogeneous electron gases or by considering either ion or target in isolation. (paper)

  2. Average stopping powers and the use of non-analyte spiking for the determination of phosphorus and sodium by PIPPS

    International Nuclear Information System (INIS)

    Olivier, C.; Morland, H.J.

    1991-01-01

    By using particle induced prompt photon spectrometry, PIPPS, the ratios of the average stopping powers in samples and standards can be used to determine elemental compositions. Since the average stopping powers in the samples are in general unknown, this procedure poses a problem. It has been shown that by spiking the sample with a known amount of a compound with known stopping power and containing a non-analyte element, appropriate stopping powers in the samples can be determined by measuring the prompt gamma-ray yields induced in the spike. Using 5-MeV protons and lithium compounds as non-analyte spikes, sodium and phosphorus were determined in ivory, while sodium was determined in geological samples. For the stopping power determinations in the samples the 429-keV 7 Li n(1,0) and 478-keV 7 Li (1,0) gamma rays were measured, while for phosphorus and sodium determinations the high yield 1,266-keV 31 P (1,0), 440-keV 23 Na (1,0), 1,634-keV, Na 23 α(1,0) and 1,637-keV 23 Na (2,1) gamma rays were used. The method was tested by analyzing the standard reference materials SRM 91, 120c and 694

  3. Calculations and measurements of the scintillator-to-water stopping power ratio of liquid scintillators for use in proton radiotherapy

    International Nuclear Information System (INIS)

    Scott Ingram, W.; Robertson, Daniel; Beddar, Sam

    2015-01-01

    Liquid scintillators are a promising detector for high-resolution three-dimensional proton therapy dosimetry. Because the scintillator comprises both the active volume of the detector and the phantom material, an ideal scintillator will exhibit water equivalence in its radiological properties. One of the most fundamental of these is the scintillator’s stopping power. The objective of this study was to compare calculations and measurements of scintillator-to-water stopping power ratios to evaluate the suitability of the liquid scintillators BC-531 and OptiPhase HiSafe 3 for proton dosimetry. We also measured the relative scintillation output of the two scintillators. Both calculations and measurements show that the linear stopping power of OptiPhase is significantly closer to water than that of BC-531. BC-531 has a somewhat higher scintillation output. OptiPhase can be mixed with water at high concentrations, which further improves its scintillator-to-water stopping power ratio. However, this causes the solution to become cloudy, which has a negative impact on the scintillation output and spatial resolution of the detector. OptiPhase is preferred over BC-531 for proton dosimetry because its density and scintillator-to-water stopping power ratio are more water equivalent

  4. Electronic stopping power calculation for water under the Lindhard formalism for application in proton computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Guerrero, A. F., E-mail: afguerreror@uqvirtual.edu.co [Departamento de Física, Universidad Del Quindío Cra 15 # 12N Armenia, Quindío (Colombia); Mesa, J., E-mail: jmesa@ibb.unesp.br [Instituto de Biociências de Botucatu da UNESP Distrito de Rubião Jr. s/n°, 18618-000, Botucatu, SP (Brazil)

    2016-07-07

    Because of the behavior that charged particles have when they interact with biological material, proton therapy is shaping the future of radiation therapy in cancer treatment. The planning of radiation therapy is made up of several stages. The first one is the diagnostic image, in which you have an idea of the density, size and type of tumor being treated; to understand this it is important to know how the particles beam interacts with the tissue. In this work, by using de Lindhard formalism and the Y.R. Waghmare model for the charge distribution of the proton, the electronic stopping power (SP) for a proton beam interacting with a liquid water target in the range of proton energies 10{sup 1} eV - 10{sup 10} eV taking into account all the charge states is calculated.

  5. Mean excitation energies for use in Bethe's stopping-power formula

    International Nuclear Information System (INIS)

    Berger, M.J.; Seltzer, S.M.

    1983-01-01

    A review has been made of the mean excitation energies that can be derived from the analysis of stopping-power and range measurements, and from semi-empirical dipole oscillator-strength distributions for gases and dielectric-response functions for solids. On the basis of this review, mean excitation energies have been selected for 43 elemental substances and 54 compounds. Additivity rules have also been considered which allow one to estimate the mean excitation energies for compounds for which no direct data are available. These additivity rules are based on the use of mean excitation energies for atomic constituents which, to a certain extent, take into account the effects of chemical binding and physical aggregation

  6. Mean excitation energy of polystyrene extracted from proton-stopping-power measurements

    International Nuclear Information System (INIS)

    Porter, L.E.

    1980-01-01

    The measured stopping power of polystyrene for 2.2- to 5.9-MeV protons has been analyzed with the Bloch projectile-z 4 correction term and a modified low-velocity projectile-z 3 term included in the Bethe-Bloch formula. When the full-strength Walske K-shell correction was utilized, the mean excitation energy corresponding to the best fit of the measurements was (71.1 +- 1.8) eV. This result was obtained for a value of the free parameter of the low-velocity projectile-z 3 effect formalism of 1.90 +- 0.05, whether or not a Walske L-shell correction was included

  7. Experimental verification of ion stopping power prediction from dual energy CT data in tissue surrogates

    Science.gov (United States)

    Farace, Paolo

    2014-11-01

    A two-steps procedure is presented to convert dual-energy CT data to stopping power ratio (SPR), relative to water. In the first step the relative electron density (RED) is calculated from dual-energy CT-numbers by means of a bi-linear relationship: RED = a HUscH + b HUscL + c, where HUscH and HUscL are scaled units (HUsc = HU + 1000) acquired at high and low energy respectively, and the three parameters a, b and c has to be determined for each CT scanner. In the second step the RED values were converted into SPR by means of published poly-line functions, which are invariant as they do not depend on a specific CT scanner. The comparison with other methods provides encouraging results, with residual SPR error on human tissue within 1%. The distinctive features of the proposed method are its simplicity and the generality of the conversion functions.

  8. Experimental verification of ion stopping power prediction from dual energy CT data in tissue surrogates.

    Science.gov (United States)

    Farace, Paolo

    2014-11-21

    A two-steps procedure is presented to convert dual-energy CT data to stopping power ratio (SPR), relative to water. In the first step the relative electron density (RED) is calculated from dual-energy CT-numbers by means of a bi-linear relationship: RED=a HUscH+b HUscL+c, where HUscH and HUscL are scaled units (HUsc=HU+1000) acquired at high and low energy respectively, and the three parameters a, b and c has to be determined for each CT scanner. In the second step the RED values were converted into SPR by means of published poly-line functions, which are invariant as they do not depend on a specific CT scanner. The comparison with other methods provides encouraging results, with residual SPR error on human tissue within 1%. The distinctive features of the proposed method are its simplicity and the generality of the conversion functions.

  9. Stopping power for arbitrary angle between test particle velocity and magnetic field

    International Nuclear Information System (INIS)

    Cereceda, Carlo; Peretti, Michel de; Deutsch, Claude

    2005-01-01

    Using the longitudinal dielectric function derived previously for charged test particles in helical movement around magnetic field lines, the numerical convergence of the series involved is found and the double numerical integrations on wave vector components are performed yielding the stopping power for arbitrary angle between the test particle velocity and magnetic field. Calculations are performed for particle Larmor radius larger and shorter than Debye length, i.e., for protons in a cold magnetized plasma and for thermonuclear α particles in a dense, hot, and strongly magnetized plasma. A strong decrease is found for the energy loss as the angle varies from 0 to π/2. The range of thermonuclear α particles as a function of the velocity angle with respect to the magnetic field is also given

  10. On beam quality and stopping power ratios for high-energy x-rays

    International Nuclear Information System (INIS)

    Johnsson, S.A.; Ceberg, C.P.; Knoeoes, T.; Nilsson, P.

    2000-01-01

    The aim of this work is to quantitatively compare two commonly used beam quality indices, TPR(20/10) and %dd(10) x , with respect to their ability to predict stopping power ratios (water to air), s w,air , for high-energy x-rays. In particular, effects due to a varied amount of filtration of the photon beam will be studied. A new method for characterizing beam quality is also presented, where the information we strive to obtain is the moments of the spectral distribution. We will show how the moments enter into a general description of the transmission curve and that it is possible to correlate the moments to s w,air with a unique and simple relationship. Comparisons with TPR(20/10) and %dd(10) x show that the moments are well suited for beam quality specification in terms of choosing the correct s w,air . (author)

  11. Average stopping powers for electron and photon sources for radiobiological modeling and microdosimetric applications

    Science.gov (United States)

    Vassiliev, Oleg N.; Kry, Stephen F.; Grosshans, David R.; Mohan, Radhe

    2018-03-01

    This study concerns calculation of the average electronic stopping power for photon and electron sources. It addresses two problems that have not yet been fully resolved. The first is defining the electron spectrum used for averaging in a way that is most suitable for radiobiological modeling. We define it as the spectrum of electrons entering the sensitive to radiation volume (SV) within the cell nucleus, at the moment they enter the SV. For this spectrum we derive a formula that combines linearly the fluence spectrum and the source spectrum. The latter is the distribution of initial energies of electrons produced by a source. Previous studies used either the fluence or source spectra, but not both, thereby neglecting a part of the complete spectrum. Our derived formula reduces to these two prior methods in the case of high and low energy sources, respectively. The second problem is extending electron spectra to low energies. Previous studies used an energy cut-off on the order of 1 keV. However, as we show, even for high energy sources, such as 60Co, electrons with energies below 1 keV contribute about 30% to the dose. In this study all the spectra were calculated with Geant4-DNA code and a cut-off energy of only 11 eV. We present formulas for calculating frequency- and dose-average stopping powers, numerical results for several important electron and photon sources, and tables with all the data needed to use our formulas for arbitrary electron and photon sources producing electrons with initial energies up to  ∼1 MeV.

  12. Defect creation by swift heavy ions: materials modifications in the electronic stopping power regime

    International Nuclear Information System (INIS)

    Toulemonde, M.

    1994-01-01

    The material modifications by swift heavy ions in the electronic stopping power regime are puzzling question: How the energy deposited on the electrons can induced material modifications? In order to answer to this question, the modifications induced in non-radiolytic materials are described and compared to the predictions. In first part the main experimental observations is presented taking into account the irradiation parameters. Then it is shown that the initial phases of the material are very important. Amorphous materials, whatever it is a metal, a semiconductor or an insulator, are till now all sensitive to the high electronic excitation induced by the slowing down of a swift heavy ion. All oxide materials, insulators or conductors, are also sensitive even the MgO, one of most famous exceptions. Crystalline metals or semiconductors are intermediate cases: some are insensitive like Cu and Si respectively while Fe and GeS are sensitive. The main feature is the different values of the electronic stopping power threshold of material modifications. The evolution of the damage creation is described showing that the damage morphology seems to be the same whatever the material is amorphous or crystalline. In second part a try of interpretation of the experimental results will be done on the behalf of the two following models: The Coulomb spike and the thermal spike models. It will be shown that there is some agreement with limited predictions made in the framework of the Coulomb spike model. But it appears that the thermal spike model can account for most of the experimental data using only one free parameter: The electron-phonon strength which is a physical characteristic of the irradiated material. (author). 4 figs., 1 tab., 64 refs

  13. The stopping power and energy straggling of the energetic C and O ions in polyimide

    Energy Technology Data Exchange (ETDEWEB)

    Mikšová, R., E-mail: miksova@ujf.cas.cz [Nuclear Physics Institute of the Academy of Science of the Czech Republic v.v.i, 250 68 Rez (Czech Republic); Department of Physics, Faculty of Science, J.E. Purkinje University, Ceske Mladeze 8, 400 96 Usti nad Labem (Czech Republic); Macková, A. [Nuclear Physics Institute of the Academy of Science of the Czech Republic v.v.i, 250 68 Rez (Czech Republic); Department of Physics, Faculty of Science, J.E. Purkinje University, Ceske Mladeze 8, 400 96 Usti nad Labem (Czech Republic); Slepička, P. [Department of Solid State Engineering, Institute of Chemical Technology, 166 28 Prague (Czech Republic)

    2016-03-15

    The stopping power and energy straggling of {sup 12}C{sup n+} and {sup 16}O{sup n+} heavy ions in the energy range 5.3–8.0 MeV in 8 μm thick polyimide (PI) foil were measured by means of an indirect transmission method using a half-covered a PIPS detector. Ions scattered from thin gold layer, under the scattering angle 150° were detected and the spectrum of ions penetrating the PI foil and without foil was recorded. The values of the experimentally determined stopping powers were compared to the calculated data by SRIM-2013 and MSTAR codes. Measured data were in good agreement with data calculated by SRIM-2013, especially for C ions was observed better agreement than for O ions. The energy straggling was determined and compared to those calculated by using Bohr’s, Bethe–Livingston and Yang models. The measured energy straggling values in the PI foil was corrected for foil roughness and thickness inhomogeneity determined from AFM. Bethe–Livingston predicting formula has been modified to make it appropriate for thicker targets. The energy straggling determined in our experiment was obtained higher than Bohr’s predicted value; the predictions by Yang are in good agreement with our experiment. Bethe–Livingston formulation of the energy straggling shows better agreement with the experimental data after the modified formula implementation which assumes that the thick target was consisted to be composed of n-number of thin layers. Influence of the charge-exchange phenomena to the energy straggling of C and O ions in PI was discussed.

  14. Power Minimization through Packet Retention in Cognitive Radio Sensor Networks under Interference and Delay Constraints: An Optimal Stopping Approach

    Directory of Open Access Journals (Sweden)

    Amr Y. Elnakeeb

    2016-04-01

    Full Text Available The aim of this article is twofold: First, we study the problem of packets retention in a queue with the aim of minimizing transmission power in delay-tolerant applications. The problem is classified as an optimal stopping problem. The optimal stopping rule has been derived as well. Optimal number of released packets is determined in each round through an Integer Linear Programming (ILP optimization problem. This transmission paradigm is tested via simulations in an interference-free environment leading to a significant reduction in transmission power (at least 55%. Second, we address the problem of applying the scheme of packets retention through the Optimal Stopping Policy (OSP to underlay Cognitive Radio Sensor Networks (CRSNs where strict interference threshold does exist. Simulations proved that our scheme outperforms traditional transmission method as far as dropped packet rate and Average Power per Transmitted Packet (APTP are concerned.

  15. A simulation study on proton computed tomography (CT) stopping power accuracy using dual energy CT scans as benchmark

    DEFF Research Database (Denmark)

    Hansen, David Christoffer; Seco, Joao; Sørensen, Thomas Sangild

    2015-01-01

    Background. Accurate stopping power estimation is crucial for treatment planning in proton therapy, and the uncertainties in stopping power are currently the largest contributor to the employed dose margins. Dual energy x-ray computed tomography (CT) (clinically available) and proton CT (in...... development) have both been proposed as methods for obtaining patient stopping power maps. The purpose of this work was to assess the accuracy of proton CT using dual energy CT scans of phantoms to establish reference accuracy levels. Material and methods. A CT calibration phantom and an abdomen cross section...... phantom containing inserts were scanned with dual energy and single energy CT with a state-of-the-art dual energy CT scanner. Proton CT scans were simulated using Monte Carlo methods. The simulations followed the setup used in current prototype proton CT scanners and included realistic modeling...

  16. ESTAR, PSTAR, ASTAR. A PC package for calculating stopping powers and ranges of electrons, protons and helium ions. Version 2

    International Nuclear Information System (INIS)

    Berger, M.J.

    1993-01-01

    A PC package is documented for calculating stopping powers and ranges of electrons, protons and helium ions in matter for energies from 1 keV up to 10 GeV. Stopping powers and ranges for electrons can be calculated for any element, compound or mixture. Stopping powers and ranges of protons and helium ions can be calculated for 74 materials (26 elements and 48 compounds and mixtures). The files are stored on two HD diskettes in compressed form. Both executable files for IBM PC and Fortran-77 source files are provided. All three programs require 5.2 Mb of disk space. This set of two diskettes with detailed documentation is available upon request, cost free, from the IAEA Nuclear Data Section. (author). 25 refs, 4 tabs

  17. Quiet: The Power of Introvert in a World That Can’t Stop Talking

    Directory of Open Access Journals (Sweden)

    Sean Schat

    2012-11-01

    Full Text Available Do you pay attention to the differences between extroversion and introversion? It can be fascinating to consider who is and is not aware of  the distinction between the two, as well as the significant formative role they both play in daily perceptions and interactions.  In my experience, more often than not it is the introverts who recognize and appreciate the difference, while too many extroverts remain unaware. In  Quiet: The Power of Introverts in a World That Can’t Stop Talking(2012, Susan Cain reminds us of the potency and power of the gift of introversion.  She challenges her readers to recognize and celebrate the unique insights and contributions that may be latent in communities and organizations—present, but hidden from view, and likely to remain so unless given the space to flourish and to find a voice. She also suggests that creating a space for the introvert voice may bring unforeseen blessings to an organization or community.

  18. Electronic stopping powers for fluorine ions in {sup 19}F{sup +}-implanted AgGaS{sub 2} crystal

    Energy Technology Data Exchange (ETDEWEB)

    Liu Xiangdong; Xia Yueyuan; Lu Qingming; Li Feng; Huang Boda

    2004-01-15

    Electronic stopping powers for 80-350 keV {sup 19}F ions in AgGaS{sub 2} were obtained by range measurement. Depth profiles of {sup 19}F in AgGaS{sub 2} were measured by using the {sup 19}F(p,{alpha}{gamma}){sup 16}O resonant nuclear reaction at E{sub R}=872.1 keV. A proper convolution calculation method was used to extract the true distribution of fluorine from the experimental excitation yield curves. The electronic stopping powers were derived through fitting the projected range distributions, simulated by using the TRIM/XLL code, to the experimentally measured range distributions. The electronic stopping cross sections were compared with those obtained from Monte Carlo simulation codes.

  19. Electronic stopping powers for fluorine ions in 19F+-implanted AgGaS2 crystal

    International Nuclear Information System (INIS)

    Liu Xiangdong; Xia Yueyuan; Lu Qingming; Li Feng; Huang Boda

    2004-01-01

    Electronic stopping powers for 80-350 keV 19 F ions in AgGaS 2 were obtained by range measurement. Depth profiles of 19 F in AgGaS 2 were measured by using the 19 F(p,αγ) 16 O resonant nuclear reaction at E R =872.1 keV. A proper convolution calculation method was used to extract the true distribution of fluorine from the experimental excitation yield curves. The electronic stopping powers were derived through fitting the projected range distributions, simulated by using the TRIM/XLL code, to the experimentally measured range distributions. The electronic stopping cross sections were compared with those obtained from Monte Carlo simulation codes

  20. Efficiency improvement in proton dose calculations with an equivalent restricted stopping power formalism

    Science.gov (United States)

    Maneval, Daniel; Bouchard, Hugo; Ozell, Benoît; Després, Philippe

    2018-01-01

    The equivalent restricted stopping power formalism is introduced for proton mean energy loss calculations under the continuous slowing down approximation. The objective is the acceleration of Monte Carlo dose calculations by allowing larger steps while preserving accuracy. The fractional energy loss per step length ɛ was obtained with a secant method and a Gauss-Kronrod quadrature estimation of the integral equation relating the mean energy loss to the step length. The midpoint rule of the Newton-Cotes formulae was then used to solve this equation, allowing the creation of a lookup table linking ɛ to the equivalent restricted stopping power L eq, used here as a key physical quantity. The mean energy loss for any step length was simply defined as the product of the step length with L eq. Proton inelastic collisions with electrons were added to GPUMCD, a GPU-based Monte Carlo dose calculation code. The proton continuous slowing-down was modelled with the L eq formalism. GPUMCD was compared to Geant4 in a validation study where ionization processes alone were activated and a voxelized geometry was used. The energy straggling was first switched off to validate the L eq formalism alone. Dose differences between Geant4 and GPUMCD were smaller than 0.31% for the L eq formalism. The mean error and the standard deviation were below 0.035% and 0.038% respectively. 99.4 to 100% of GPUMCD dose points were consistent with a 0.3% dose tolerance. GPUMCD 80% falloff positions (R80 ) matched Geant’s R80 within 1 μm. With the energy straggling, dose differences were below 2.7% in the Bragg peak falloff and smaller than 0.83% elsewhere. The R80 positions matched within 100 μm. The overall computation times to transport one million protons with GPUMCD were 31-173 ms. Under similar conditions, Geant4 computation times were 1.4-20 h. The L eq formalism led to an intrinsic efficiency gain factor ranging between 30-630, increasing with the prescribed accuracy of simulations. The

  1. Stopping power of charged particles from 10 eV/amu to 10 GeV/amu

    International Nuclear Information System (INIS)

    Nakane, Yoshihiro; Tanaka, Shun-ichi; Furihata, Shiori; Iwai, Satoshi.

    1993-08-01

    Electric collision, nuclear collision and total stopping powers in 10 kinds of elements: H 2 , He, Be, C, Al, Fe, Cu, W, Pb and U, and 4 kinds of materials: water, phantom, LiF-TLD and SSNTD (solid state neutron track detector) have been calculated for 10 kinds of charged particles from 10 eV/amu to 10 GeV/amu with STOPPING, SPAR, and RSTAN/RSHEV codes, in which the charged particles are important projectiles for evaluating the dose and detector responses of radiations, and for accelerator shielding calculations. Calculated data are presented in Table and Figure. (author)

  2. Development of methodology for assessment of absorbed dose and stopping power for low energy conversion electrons

    International Nuclear Information System (INIS)

    Almeida, Ivan Pedro Salati de

    1995-08-01

    The evaluation of absorbed dose in the case of external and internal contamination due to radionuclides is sometimes hard, because of the difficulties in the assessment of the absorbed dose caused by electrons with energy less than 100 KeV in mucous membrane. In this work, a methodology for assessment of absorbed dose and stopping power in VYNS (co-polymer of polivinyl chloride - acetate) absorbers, for the 62.5 KeV and 84-88 KeV energy 109 Cd conversion electrons, working with a 4 π proportional pressurized detector, is presented. In order to assure the reproducibility of measurement conditions, one of the detector halves has been used to obtain a spectrum of a thin 109 Cd source, without absorber. The other half of the detector was used in concomitance to obtain spectra with different thicknesses if absorber. The absorbed energy was obtained subtracting each spectrum with absorber from the spectrum without absorber, which were stored in a microcomputer connected to signal processing systems by ACE type interface. The VYNS weight and thickness were evaluated using common radionuclide metrology procedures. As VYNS has characteristics similar to a tissue equivalent material, the results obtained are consistent with dosimetric concepts and have a good agreement with those of the literature. (author)

  3. Experimental study of stopping powers for ions of intermediate atomic numbers

    International Nuclear Information System (INIS)

    Bucher, R.G.

    1975-01-01

    A technique has been developed to measure the energy loss as a function of ion atomic number for the fragments emitted by the spontaneous fission of 252 Cf; the atomic numbers of the fragments were directly measured by the detection of a characteristic K x-ray. The measured energy losses were compared with the theories of Lindhard and of Firsov, with the tabulation of Northcliffe and Schilling, and with the semiempirical formula of Moak and Brown. For the light fragments the measured values are in good agreement with the predictions of Moak--Brown and Northcliffe--Schilling; for the heavy fragments the measured values are approximately midway between the prediction of Moak--Brown and Northcliffe--Schilling and those of Lindhard for xi/sub epsilon/ = 2. The difference in the stopping powers for adjacent ion atomic numbers Z 1 was concluded to be (1.8 +- 0.2) percent for 40 less than or equal to Z 1 less than or equal to 45 at a velocity of 1.36 cm/ns and (2.0 +- 0.1) percent for 53 less than or equal to Z 1 less than or equal to 58 at a velocity of 1.04 cm/ns

  4. Stopping powers of Zr, Pd, Cd, In and Pb for 6.5 MeV protons and mean excitation energies

    International Nuclear Information System (INIS)

    Ishiwari, R.; Shiomi, N.; Sakamoto, N.

    1983-01-01

    Stopping powers of Zr, Pd, Cd, In and Pb have been measured for 6.5 MeV protons. Mean excitation energies have been extracted from the stopping power data by taking into account Bloch correction and Z 1 3 correction. For the shell correction the Bonderup shell correction has been used. The results agree fairly well with those of other authors

  5. Ex vivo validation of a stoichiometric dual energy CT proton stopping power ratio calibration

    Science.gov (United States)

    Xie, Yunhe; Ainsley, Christopher; Yin, Lingshu; Zou, Wei; McDonough, James; Solberg, Timothy D.; Lin, Alexander; Teo, Boon-Keng Kevin

    2018-03-01

    A major source of uncertainty in proton therapy is the conversion of Hounsfield unit (HU) to proton stopping power ratio relative to water (SPR). In this study, we measured and quantified the accuracy of a stoichiometric dual energy CT (DECT) SPR calibration. We applied a stoichiometric DECT calibration method to derive the SPR using CT images acquired sequentially at 80 kVp and 140 kVp . The dual energy index was derived based on the HUs of the paired spectral images and used to calculate the effective atomic number (Z eff), relative electron density ({{ρ }e} ), and SPRs of phantom and biological materials. Two methods were used to verify the derived SPRs. The first method measured the sample’s water equivalent thicknesses to deduce the SPRs using a multi-layer ion chamber (MLIC) device. The second method utilized Gafchromic EBT3 film to directly compare relative ranges between sample and water after proton pencil beam irradiation. Ex vivo validation was performed using five different types of frozen animal tissues with the MLIC and three types of fresh animal tissues using film. In addition, the residual ranges recorded on the film were used to compare with those from the treatment planning system using both DECT and SECT derived SPRs. Bland-Altman analysis indicates that the differences between DECT and SPR measurement of tissue surrogates, frozen and fresh animal tissues has a mean of 0.07% and standard deviation of 0.58% compared to 0.55% and 1.94% respectively for single energy CT (SECT) and SPR measurement. Our ex vivo study indicates that the stoichiometric DECT SPR calibration method has the potential to be more accurate than SECT calibration under ideal conditions although beam hardening effects and other image artifacts may increase this uncertainty.

  6. Simplified derivation of stopping power ratio in the human body from dual-energy CT data.

    Science.gov (United States)

    Saito, Masatoshi; Sagara, Shota

    2017-08-01

    The main objective of this study is to propose an alternative parameterization for the empirical relation between mean excitation energies (I-value) and effective atomic numbers (Z eff ) of human tissues, and to present a simplified formulation (which we called DEEDZ-SPR) for deriving the stopping power ratio (SPR) from dual-energy (DE) CT data via electron density (ρ e ) and Z eff calibration. We performed a numerical analysis of this DEEDZ-SPR method for the human-body-equivalent tissues of ICRU Report 46, as objects of interest with unknown SPR and ρ e . The attenuation coefficients of these materials were calculated using the XCOM photon cross-sections database. We also applied the DEEDZ-SPR conversion to experimental DECT data available in the literature, which was measured for the tissue-characterization phantom using a dual-source CT scanner at 80 kV and 140 kV/Sn. It was found that the DEEDZ-SPR conversion enables the calculation of SPR simply by means of the weighted subtraction of an electron-density image and a low- or high-kV CT image. The simulated SPRs were in excellent agreement with the reference values over the SPR range from 0.258 (lung) to 3.638 (bone mineral-hydroxyapatite). The relative deviations from the reference SPR were within ±0.6% for all ICRU-46 human tissues, except for the thyroid that presented a -1.1% deviation. The overall root-mean-square error was 0.21%. Application to experimental DECT data confirmed this agreement within the experimental accuracy, which demonstrates the practical feasibility of the method. The DEEDZ-SPR conversion method could facilitate the construction of SPR images as accurately as a recent DECT-based calibration procedure of SPR parameterization based directly on the CT numbers in a DECT data set. © 2017 American Association of Physicists in Medicine.

  7. The gaseous emission of polymers under swift heavy ion irradiation: effect of the electronic stopping power

    International Nuclear Information System (INIS)

    Picq, V.

    2000-07-01

    This thesis contributes to a better understanding of the damaging processes, which occur in polymers under swift heavy ion irradiation. The present study is exclusively devoted to the influence of the electronic stopping power, (dE/dx)e, on the molecular emission under irradiation. The irradiated polymers are polyethylene, polypropylene and poly-butene. The (dE/dx)e of the projectiles used varies from 3.5*10 -3 MeV.mg -1 .cm 2 (electron) to 39 MeV.mg -1 .cm 2 ( 58 Ni). We used two different experimental approaches in order to identify the nature of the emitted gases: mass spectrometry and infrared spectroscopy. The first technique is non selective, therefore, we could detect the emission of H 2 and heavy molecules; it also gives information on the diffusion kinetics of the molecules formed. The use of infrared spectroscopy for this kind of analysis is new and the technique was developed at the laboratory. It enables us to identify, without any ambiguity, molecules with up to three carbon atoms. The experimental spectra are analysed by using reference spectra of pure gases, measured in our laboratory. We have quantified precisely each identified gas, and we have followed the evolution of the radiochemical yields with increasing (dE/dx)e. The results, obtained at different (dE/dx)e, inform us on the different mechanisms of gas molecules formation, for example the side group departure and, at high (dE/dx)e, the fragmentation of the main chain which is due to multiple ionisation of the macromolecule. (author)

  8. SU-E-J-149: Secondary Emission Detection for Improved Proton Relative Stopping Power Identification

    Energy Technology Data Exchange (ETDEWEB)

    Saunders, J; Musall, B; Erickson, A [Georgia Institute of Technology, Atlanta, GA (Georgia)

    2015-06-15

    Purpose: This research investigates application of secondary prompt gamma (PG) emission spectra, resulting from nuclear reactions induced by protons, to characterize tissue composition along the particle path. The objective of utilizing the intensity of discrete high-energy peaks of PG is to improve the accuracy of relative stopping power (RSP) values available for proton therapy treatment planning on a patient specific basis and to reduce uncertainty in dose depth calculations. Methods: In this research, MCNP6 was used to simulate PG emission spectra generated from proton induced nuclear reactions in medium of varying composition of carbon, oxygen, calcium and nitrogen, the predominant elements found in human tissue. The relative peak intensities at discrete energies predicted by MCNP6 were compared to the corresponding atomic composition of the medium. Results: The results have shown a good general agreement with experimentally measured values reported by other investigators. Unexpected divergence from experimental spectra was noted in the peak intensities for some cases depending on the source of the cross-section data when using compiled proton table libraries vs. physics models built into MCNP6. While the use of proton cross-section libraries is generally recommended when available, these libraries lack data for several less abundant isotopes. This limits the range of their applicability and forces the simulations to rely on physics models for reactions with natural atomic compositions. Conclusion: Current end-of-range proton imaging provides an average RSP for the total estimated track length. The accurate identification of tissue composition along the incident particle path using PG detection and characterization allows for improved determination of the tissue RSP on the local level. While this would allow for more accurate depth calculations resulting in tighter treatment margins, precise understanding of proton beam behavior in tissue of various

  9. Atmospheric Muon Lifetime, Standard Model of Particles and the Lead Stopping Power for Muons

    Science.gov (United States)

    Gutarra-Leon, Angel; Barazandeh, Cioli; Majewski, Walerian

    2017-01-01

    The muon is a fundamental particles of matter. It decays into three other leptons through an exchange of the weak vector bosons W +/W-. Muons are present in the atmosphere from cosmic ray showers. By detecting the time delay between arrival of the muon and an appearance of the decay electron in our detector, we'll measure muon's lifetime at rest. From the lifetime we should be able to find the ratio gw /MW of the weak coupling constant gw (a weak analog of the electric charge) to the mass of the W-boson MW. Vacuum expectation value v of the Higg's field, which determines the masses of all particles of the Standard Model (SM), could be then calculated from our muon experiment as v =2MWc2/gw =(τ m μc2/6 π3ĥ)1/4m μc2 in terms of muon mass mµand muon lifetime τ only. Using known experimental value for MWc2 = 80.4 GeV we'll find the weak coupling constant gw. Using the SM relation e =gwsin θ√ hc ɛ0 with the experimental value of the Z0-photon weak mixing angle θ = 29o we could find from our muon lifetime the value of the elementary electric charge e. We'll determine the sea-level fluxes of low-energy and high-energy cosmic muons, then we'll shield the detector with varying thicknesses of lead plates and find the energy-dependent muon stopping power in lead.

  10. The selection of stopping power and mass energy absorption coefficient data for the HPA Code of Practice for dosimetry

    International Nuclear Information System (INIS)

    Williams, P.C.

    1985-01-01

    The author draws attention to a discussion by Cunningham and Schultz (1984) which states that, 'with the exception of the NACP and AAPM protocols, the selection of stopping power and energy absorption coefficient ratios has been based upon only the stated accelerating potential of the accelerator', and points out that the HPA Revised Code of Practice should be added to these exceptions. In calculating the HPA's new Csub(lambda) values, a similar, but not identical, approach was taken in order to determine the stopping power and absorption coefficient ratios at each radiation quality. It was recognised that the approximation of a spectrum to a monoenergetic spectrum of between 0.4 and 0.45 of the maximum energy, as had been done in calculating the values, given in ICRU Report 14, was incorrect. (U.K.)

  11. Theoretical studies on the stopping power of deuterium-tritium mixed with uranium plasmas for α particles

    International Nuclear Information System (INIS)

    Wang, Zhigang; Fu, Zhen-Guo; Zhang, Ping

    2014-01-01

    The stopping power of a compressed and highly ionized deuterium-tritium (DT) and uranium (U) plasma for α particles at very high temperatures (T = 5 keV) is examined theoretically with the dimensional continuation method. We show that with increasing density of U, both the magnitude and width of the resonance peak in the stopping power (as a function of the α particle energy), increases because of the ions, while the penetration distance of the α particles decreases. A simple relation of decreasing penetration distance as a function of plasma density is observed, which may be useful for inertial confinement fusion experiments. Moreover, by comparing the results with the case of a DT plasma mixed with beryllium, we find that the effect of a higher Z plasma is stronger, with regard to energy loss as well as the penetration distance of α particles, than that of a lower Z plasma

  12. Calculation of the protons stopping power in water using dielectric formalism in the MELF-GOS approach

    International Nuclear Information System (INIS)

    Ribeiro, Franciane; Mazer, Amanda Cristina; Hormaza, Joel Mesa

    2016-01-01

    In order to calculate the stopping power of protons, there are many very successful models at high energies, which are extrapolated to low-energy regions. From the point of view of application of proton beam in cancer treatment is just this low energy region the most relevant due to the dose deposition profile in depth for protons. In this work, we present a calculation of the stopping power of protons in a water target using the dielectric formalism in MELF-GOS approach. The results when compared to other models show good agreement for energies above 100 keV and lower values below this energy. This result should impact the range of values of protons and the Bragg peak position. (author)

  13. Calculation of inelastic mean free path and stopping power for electrons in solids from an optical-data model

    International Nuclear Information System (INIS)

    Fernandez-Varea, J.M.; Mayol, R.; Salvat, F.; Liljequist, D.

    1992-11-01

    The numerical calculation of electron inelastic mean free path and stopping power from an optical-data model recently proposed by Fernandez-Varea et al. is described in detail. Explicit expressions for the one-electron total cross sections of the two-modes model of the free-electron gas and the δ-oscillator are derived. The inelastic mean free path and the stopping power are obtained as integrals of these one-electron total cross sections weighted by the optical as integrals of these one-electron total cross sections weighted by the optical oscillator strength. The integrals can be easily evaluated, with a selected accuracy, by using the FORTRAN 77 subroutine GABQ described here, which implements a 20-points Gauss adaptive bipartition quadrature method. Source listings of FORTRAN 77 subroutines to compute the one-electron total cross sections are also given

  14. Low-energy proton stopping power of N2, O2, and water vapor, and deviations from Bragg's rule

    International Nuclear Information System (INIS)

    Xu, Y.J.; Khandelwal, G.S.; Wilson, J.W.

    1984-01-01

    A modified local-plasma model, based on the works of Lindhard and Winther, and Bethe, Brown, and Walske is established. The Gordon-Kim model for molecular-electron density is used to calculate stopping power of N 2 , O 2 , and water vapor for protons of energy ranging from 40 keV to 2.5 MeV, resulting in good agreement with experimental data. Deviations from Bragg's rule are evaluated and are discussed under the present theoretical model

  15. Energy dependence of the stopping power of MeV 16O ions in a laser-produced plasma

    International Nuclear Information System (INIS)

    Sakumi, A.; Shibata, K.; Sato, R.; Tsubuku, K.; Nishimoto, T.; Hasegawa, J.; Ogawa, M.; Oguri, Y.; Katayama, T.

    2001-01-01

    The energy dependence of the stopping power of 16 O ions in a laser-produced plasma target was experimentally investigated in the projectile energy range of 150-350 keV/u. In order to produce the target plasma a Q-Switched Nd-glass laser was focused onto a small lithium hydride (LiH) pellet. The plasma electron temperature and the electron line density were 15 eV and 2x10 17 cm -2 , respectively. The energy loss of 16 O ions in the plasma was measured by a time-of-flight (TOF) method. We found that the stopping power in the plasma agreed with the theoretical estimation based on a modified Bohr equation with correction at low velocities. In this evaluation, the effective charge of the projectile was calculated by means of rate equations on the loss and capture of electrons. It has been also found that in this projectile energy range the stopping power of the 16 O ions in the plasma still increases with decreasing projectile energy, while it decreases in cold equivalent

  16. Studies of endothelial monolayer formation on irradiated poly-L-lactide acid with ions of different stopping power and velocity

    Energy Technology Data Exchange (ETDEWEB)

    Arbeitman, Claudia R. [CONICET – Consejo Nacional de Investigaciones Científicas y Técnicas (Argentina); Gerencia de Investigación y Aplicaciones, TANDAR-CNEA (Argentina); UNQ – IMBICE – CCT – CONICET – LA PLATA (Argentina); Grosso, Mariela F. del [CONICET – Consejo Nacional de Investigaciones Científicas y Técnicas (Argentina); Gerencia de Investigación y Aplicaciones, TANDAR-CNEA (Argentina); Ibañez, Irene L. [CONICET – Consejo Nacional de Investigaciones Científicas y Técnicas (Argentina); Behar, Moni [Instituto de Física, UFRGS, Porto Alegre, RS (Brazil); Grasselli, Mariano [UNQ – IMBICE – CCT – CONICET – LA PLATA (Argentina); Bermúdez, Gerardo García [Gerencia de Investigación y Aplicaciones, TANDAR-CNEA (Argentina)

    2015-12-15

    In this work we study cell viability, proliferation and morphology of bovine aortic endothelial cells (BAEC) cultured on poly-L-lactide acid (PLLA) modified by heavy ion irradiation. In a previous study comparing ions beams with the same stopping power we observed an increase in cell density and a better cell morphology at higher ion velocities. In the present work we continued this study using heavy ions beam with different stopping power and ion velocities. To this end thin films of 50 μm thickness were irradiated with 2 MeV/u and 0.10 MeV/u ion beams provided the Tandar (Buenos Aires, Argentina) and Tandetron (Porto Alegre, Brazil) accelerators, respectively. The results suggest that a more dense and elongated cell shapes, similar to the BAEC cells on the internal surface of bovine aorta, was obtained for stopping power of 18.2–22.1 MeV cm{sup 2} mg{sup −1} and ion velocity of 2 MeV/u. On the other hand, for low ion velocity 0.10 MeV/u the cells present a more globular shapes.

  17. Studies of endothelial monolayer formation on irradiated poly-L-lactide acid with ions of different stopping power and velocity

    International Nuclear Information System (INIS)

    Arbeitman, Claudia R.; Grosso, Mariela F. del; Ibañez, Irene L.; Behar, Moni; Grasselli, Mariano; Bermúdez, Gerardo García

    2015-01-01

    In this work we study cell viability, proliferation and morphology of bovine aortic endothelial cells (BAEC) cultured on poly-L-lactide acid (PLLA) modified by heavy ion irradiation. In a previous study comparing ions beams with the same stopping power we observed an increase in cell density and a better cell morphology at higher ion velocities. In the present work we continued this study using heavy ions beam with different stopping power and ion velocities. To this end thin films of 50 μm thickness were irradiated with 2 MeV/u and 0.10 MeV/u ion beams provided the Tandar (Buenos Aires, Argentina) and Tandetron (Porto Alegre, Brazil) accelerators, respectively. The results suggest that a more dense and elongated cell shapes, similar to the BAEC cells on the internal surface of bovine aorta, was obtained for stopping power of 18.2–22.1 MeV cm 2 mg −1 and ion velocity of 2 MeV/u. On the other hand, for low ion velocity 0.10 MeV/u the cells present a more globular shapes.

  18. Technical Note: On the calculation of stopping-power ratio for stoichiometric calibration in proton therapy

    Energy Technology Data Exchange (ETDEWEB)

    Ödén, Jakob [Department of Medical Physics, Karolinska University Hospital, Stockholm SE-17176, Sweden and Department of Medical Radiation Physics, Stockholm University and Karolinska Institutet, Stockholm SE-17176 (Sweden); Zimmerman, Jens; Nowik, Patrik; Poludniowski, Gavin, E-mail: gavin.poludniowski@karolinska.se [Department of Medical Physics, Karolinska University Hospital, Stockholm SE-17176 (Sweden); Bujila, Robert [Department of Medical Physics, Karolinska University Hospital, Stockholm SE-17176, Sweden and Department of Physics, Royal Institute of Technology, Stockholm SE-10691 (Sweden)

    2015-09-15

    Purpose: The quantitative effects of assumptions made in the calculation of stopping-power ratios (SPRs) are investigated, for stoichiometric CT calibration in proton therapy. The assumptions investigated include the use of the Bethe formula without correction terms, Bragg additivity, the choice of I-value for water, and the data source for elemental I-values. Methods: The predictions of the Bethe formula for SPR (no correction terms) were validated against more sophisticated calculations using the SRIM software package for 72 human tissues. A stoichiometric calibration was then performed at our hospital. SPR was calculated for the human tissues using either the assumption of simple Bragg additivity or the Seltzer-Berger rule (as used in ICRU Reports 37 and 49). In each case, the calculation was performed twice: First, by assuming the I-value of water was an experimentally based value of 78 eV (value proposed in Errata and Addenda for ICRU Report 73) and second, by recalculating the I-value theoretically. The discrepancy between predictions using ICRU elemental I-values and the commonly used tables of Janni was also investigated. Results: Errors due to neglecting the correction terms to the Bethe formula were calculated at less than 0.1% for biological tissues. Discrepancies greater than 1%, however, were estimated due to departures from simple Bragg additivity when a fixed I-value for water was imposed. When the I-value for water was calculated in a consistent manner to that for tissue, this disagreement was substantially reduced. The difference between SPR predictions when using Janni’s or ICRU tables for I-values was up to 1.6%. Experimental data used for materials of relevance to proton therapy suggest that the ICRU-derived values provide somewhat more accurate results (root-mean-square-error: 0.8% versus 1.6%). Conclusions: The conclusions from this study are that (1) the Bethe formula can be safely used for SPR calculations without correction terms; (2

  19. Technical Note: On the calculation of stopping-power ratio for stoichiometric calibration in proton therapy

    International Nuclear Information System (INIS)

    Ödén, Jakob; Zimmerman, Jens; Nowik, Patrik; Poludniowski, Gavin; Bujila, Robert

    2015-01-01

    Purpose: The quantitative effects of assumptions made in the calculation of stopping-power ratios (SPRs) are investigated, for stoichiometric CT calibration in proton therapy. The assumptions investigated include the use of the Bethe formula without correction terms, Bragg additivity, the choice of I-value for water, and the data source for elemental I-values. Methods: The predictions of the Bethe formula for SPR (no correction terms) were validated against more sophisticated calculations using the SRIM software package for 72 human tissues. A stoichiometric calibration was then performed at our hospital. SPR was calculated for the human tissues using either the assumption of simple Bragg additivity or the Seltzer-Berger rule (as used in ICRU Reports 37 and 49). In each case, the calculation was performed twice: First, by assuming the I-value of water was an experimentally based value of 78 eV (value proposed in Errata and Addenda for ICRU Report 73) and second, by recalculating the I-value theoretically. The discrepancy between predictions using ICRU elemental I-values and the commonly used tables of Janni was also investigated. Results: Errors due to neglecting the correction terms to the Bethe formula were calculated at less than 0.1% for biological tissues. Discrepancies greater than 1%, however, were estimated due to departures from simple Bragg additivity when a fixed I-value for water was imposed. When the I-value for water was calculated in a consistent manner to that for tissue, this disagreement was substantially reduced. The difference between SPR predictions when using Janni’s or ICRU tables for I-values was up to 1.6%. Experimental data used for materials of relevance to proton therapy suggest that the ICRU-derived values provide somewhat more accurate results (root-mean-square-error: 0.8% versus 1.6%). Conclusions: The conclusions from this study are that (1) the Bethe formula can be safely used for SPR calculations without correction terms; (2

  20. Calculation of the collision stopping power of simple and composed materials for fast electrons considering the density effect with the aid of effective material parameters

    International Nuclear Information System (INIS)

    Geske, G.

    1979-01-01

    With the aid of two effective material parameters a simple expression is presented for the Bethe-Bloch-formula for the calculation of the collision stopping power of materials for fast electrons. The formula has been modified in order to include the density effect. The derivation was accomplished in connection with a formalism given by Kim. It was shown that the material dependence on the collision stopping power is entirely comprehended by the density and two effective material parameters. Thus a simple criterion is given for the comparison of materials as to their collision stopping power

  1. Stopping power of liquid water for carbon ions in the energy range between 1 MeV and 6 MeV

    International Nuclear Information System (INIS)

    Rahm, J M; Baek, W Y; Rabus, H; Hofsäss, H

    2014-01-01

    The stopping power of liquid water was measured for the first time for carbon ions in the energy range between 1 and 6 MeV using the inverted Doppler shift attenuation method. The feasibility study carried out within the scope of the present work shows that this method is well suited for the quantification of the controversial condensed phased effect in the stopping power for heavy ions in the intermediate energy range. The preliminary results of this work indicate that the stopping power of water for carbon ions with energies prevailing in the Bragg-peak region is significantly lower than that of water vapor. In view of the relatively high uncertainty of the present results, a new experiment with uncertainties less than the predicted difference between the stopping powers of both water phases is planned. (paper)

  2. Stopping power measurements with 17-GeV/c protons at the AGS or inclusive proton spectra from proton-nucleus interactions at 17 GeV/c

    International Nuclear Information System (INIS)

    Remsberg, L.P.; Barton, D.S.; Bunce, G.

    1984-01-01

    The problem of nuclear stopping power and its importance to the study of nucleus-nucleus collisions at very high energies was brought to general attention one year ago at Quark Matter 83 by Busza and Goldhaber. In this context, nuclear stopping power can be thought of as the rate of energy (or rapidity) loss of a proton traversing nuclear matter. It does not directly address the important question of energy deposition. Busza and Goldhaber showed that knowledge of nuclear stopping power is needed to estimate the minimum center-of-mass energy required in nucleus-nucleus collisions to ensure the production of very high temperatures at low baryon density. At cm energies of about 1 to 10 GeV/A, the stopping power is important in the estimation of the maximum baryon densities attainable in nucleus-nucleus collisions. The data presented are more relevant to this latter point

  3. Calculation of electronic stopping power along glancing swift heavy ion tracks in perovskites using ab initio electron density data

    Energy Technology Data Exchange (ETDEWEB)

    Osmani, O; Duvenbeck, A; Akcoeltekin, E; Meyer, R; Schleberger, M [Department of Physics, University of Duisburg-Essen, D-47048 Duisburg (Germany); Lebius, H [CIMAP, blvd Henri Becquerel, 14070 Caen (France)], E-mail: marika.schleberger@uni-due.de

    2008-08-06

    In recent experiments the irradiation of insulators of perovskite type with swift (E{approx}100 MeV) heavy ions under glancing incidence has been shown to provide a unique means to generate periodically arranged nanodots at the surface. The physical origin of these patterns has been suggested as stemming from a highly anisotropic electron density distribution within the bulk. In order to show the relevance of the electron density distribution of the target we present a model calculation for the system Xe{sup 23+} {yields} SrTiO{sub 3} that is known to produce the aforementioned surface modifications. On the basis of the Lindhard model of electronic stopping, we employ highly-resolved ab initio electron density data to describe the conversion of kinetic energy into excitation energy along the ion track. The primary particle dynamics are obtained via integration of the Newtonian equations of motion that are governed by a space- and time-dependent frictional force originating from Lindhard stopping. The analysis of the local electronic stopping power along the ion track reveals a pronounced periodic structure. The periodicity length varies strongly with the particular choice of the polar angle of incidence and is directly correlated to the experimentally observed formation of periodic nanodots at insulator surfaces.

  4. Projectile- and charge-state-dependent electron yields from ion penetration of solids as a probe of preequilibrium stopping power

    DEFF Research Database (Denmark)

    Rothard, H.; Schou, Jørgen; Groeneveld, K.-O.

    1992-01-01

    Kinetic electron-emission yields gamma from swift ion penetration of solids are proportional to the (electronic) stopping power gamma approximately Beta-S*, if the preequilibrium evolution of the charge and excitation states of the positively charged ions is taken into account. We show...... by investigating the "transport factor" beta, the energy spectrum of directly ejected recoil electrons and the evolution of ionic charge state inside solids. Estimates of the energy-loss fraction leading to electron emission and the effective charges of the ions near the surface allow a quantitative description...

  5. Ablation of a Deuterium Pellet in a Fusion Plasma Viewed as a Stopping Power Problem

    DEFF Research Database (Denmark)

    Chang, C. T.

    1983-01-01

    At present, the most exploited technology to refuel a future fusion reactor is the high speed injection of macroscopic size pellet of solid hydrogen isotopes. The basic idea is that the ablation of a pellet in a fusion reactor is mainly caused by thermal electrons (~ 10 keV) /1/. Due to the low...... sublimation energy of hydrogen isotopes, shortly after the direct impact of the electrons, a dense cloud forms around the pellet. This cloud of ablated material then serves as a stopping medium for the incoming electrons, thus prolongs the pellet life-time. As a result, the deep penetration of the pellet...

  6. Modified energy-deposition model, for the computation of the stopping-power ratio for small cavity sizes

    International Nuclear Information System (INIS)

    Janssens, A.C.A.

    1981-01-01

    This paper presents a modification to the Spencer-Attix theory, which allows application of the theory to larger cavity sizes. The modified theory is in better agreement with the actual process of energy deposition by delta rays. In the first part of the paper it is recalled how the Spencer-Attix theory can be derived from basic principles, which allows a physical interpretation of the theory in terms of a function describing the space and direction average of the deposited energy. A realistic model for the computation of this function is described and the resulting expression for the stopping-power ratio is calculated. For the comparison between the Spencer-Attix theory and this modified expression a correction factor to the ''Bragg-Gray inhomogeneous term'' has been defined. This factor has been computed as a function of cavity size for different source energies and mean excitation energies; thus, general properties of this factor have been elucidated. The computations have been extended to include the density effect. It has been shown that the computation of the inhomogeneous term can be performed for any expression describing the energy loss per unit distance of the electrons as a function of their energy. Thus an expression has been calculated which is in agreement with a quadratic range-energy relationship. In conclusion, the concrete procedure for computing the stopping-power ratio is reviewed

  7. Dirty tricks: how the nuclear lobby stopped the development of wave power in Britain

    International Nuclear Information System (INIS)

    Jeffery, J.

    1990-01-01

    It is claimed that by misrepresentation of the economic analysis of wave power generation of electricity the nuclear lobby in Britain has prevented development work to continue on wave power, in favour of nuclear power generation. The United Kingdom Department of Energy and the Central Electricity Generating Board, in favour of nuclear power, have not allowed the cost estimation of electricity from wave power generators, especially Salter's Ducks (a wave power generator generated by Professor Salter at Ednburgh University) to be known. Instead the cost (estimated at 4-12p/kWh) has been deliberately exaggerated. This has resulted in wind power becoming the favoured alternative renewable energy source of the future. (UK)

  8. Stopping power measurements for 4-5MeV/nucleon 16O, 40Ar, 63Cu and 84Kr in C, Al, Ni, Ag and Au

    International Nuclear Information System (INIS)

    Bimbot, R.; Della Negra, S.; Gardes, D.; Gauvin, H.; Fleury, A.; Hubert, F.

    1977-01-01

    The stopping powers for (4 and 5 MeV/nucleon) 16 O, 40 Ar, 63 Cu and 84 Kr have been measured in C, Al, Ni, Ag and Au media. The experimental technique consists in measuring accurately the energy of protons elastically scattered at zero degree by the incident and degraded beams. The experimental results have been compared with stopping powers calculated in different ways. Discrepancies as large as 30% have been observed for the heaviest ions in light media (C, Al), the experimental values being higher than the calculated ones. Moreover, this comparison indicates that, from these calculations, no agreement can be obtained in the whole range of incident ions and stopping media. On the contrary, a quantitative agreement was obtained by a new calculation mode which takes into account the variation of the moving ion effective charge with the atomic number of the stopping medium

  9. Evaluation of possible means to stop production of nuclear power in northwest Russia

    International Nuclear Information System (INIS)

    Skaugen, Aud K.

    2007-08-01

    This note illuminates the status and some elements in the Russian efforts on use of nuclear power, with special emphasis on northwest Russia. In addition the report describes an evaluation of the possibilities of Norwegian influence on the nuclear power in northwest Russia and Kola Peninsula

  10. Protection device for use in stopping a turbine generator in nuclear power plant

    International Nuclear Information System (INIS)

    Nagahama, Mizuo.

    1974-01-01

    Object: To supply to as great an extent as possible the residual output of a nuclear reactor to a turbine after the reactor is shutdown and to prevent overpower and motoring of a turbine by connecting a power direction relay to a secondary circuit of a current transformer and an instrumentation transformer at the high voltage side of a main transformer of a transmission bus line. Structure: When the output power of a generator after shuttingdown a nuclear reactor decreases below the sum of the mechanical losses of the turbine and the generator and the power for the house-auxiliaries connected to a fixed bus line, the direction of the current is reversed and the power is supplied from the transmission bus line through a circuit breaker for the generator and a main transformer onto the house-side, whereby a time limit relay of the power direction relay is actuated to disconnect the generator and the turbine. (Kamimura, M.)

  11. Stopping power accuracy and achievable spatial resolution of helium ion imaging using a prototype particle CT detector system

    Directory of Open Access Journals (Sweden)

    Volz Lennart

    2017-09-01

    Full Text Available A precise relative stopping power map of the patient is crucial for accurate particle therapy. Charged particle imaging determines the stopping power either tomographically – particle computed tomography (pCT – or by combining prior knowledge from particle radiography (pRad and x-ray CT. Generally, multiple Coulomb scattering limits the spatial resolution. Compared to protons, heavier particles scatter less due to their lower charge/mass ratio. A theoretical framework to predict the most likely trajectory of particles in matter was developed for light ions up to carbon and was found to be the most accurate for helium comparing for fixed initial velocity. To further investigate the potential of helium in particle imaging, helium computed tomography (HeCT and radiography (HeRad were studied at the Heidel-berg Ion-Beam Therapy Centre (HIT using a prototype pCT detector system registering individual particles, originally developed by the U.S. pCT collaboration. Several phantoms were investigated: modules of the Catphan QA phantom for analysis of spatial resolution and achievable stopping power accuracy, a paediatric head phantom (CIRS and a custom-made phantom comprised of animal meat enclosed in a 2 % agarose mixture representing human tissue. The pCT images were reconstructed applying the CARP iterative reconstruction algorithm. The MTF10% was investigated using a sharp edge gradient technique. HeRad provides a spatial resolution above that of protons (MTF1010%=6.07 lp/cm for HeRad versus MTF10%=3.35 lp/cm for proton radiography. For HeCT, the spatial resolution was limited by the number of projections acquired (90 projections for a full scan. The RSP accuracy for all inserts of the Catphan CTP404 module was found to be 2.5% or better and is subject to further optimisation. In conclusion, helium imaging appears to offer higher spatial resolution compared to proton imaging. In future studies, the advantage of helium imaging compared to other

  12. Measurement of mass stopping power of chitosan polymer loaded with TiO2 for relativistic electron interaction

    Science.gov (United States)

    Babu, S. Ramesh; Badiger, N. M.; Karidurgannavar, M. Y.; Varghese, Jolly. G.

    2018-04-01

    The Mass Stopping Power (MSP) of relativistic electrons in chitosan loaded with TiO2 of different proportions has been measured by recording the spectrum of internal conversion electrons. The internal conversion electrons of energies 614 keV from Cs137, 942 keV and 1016 keV from Bi207 source are allowed to pass through chitosan-TiO2 alloy and transmitted electrons are detected with a Si (Li) detector coupled to an 8 K multichannel analyzer. By knowing the energies of incident electrons and transmitted electrons, the energy loss and the MSP are determined. Thus measured MSP values of the alloys are compared with the values calculated using Braggs additivity rule. The disagreement between theory and experiment is found to increases with increasing TiO2 concentration in chitosan, indicating the influence of chemical environment in the properties of such polymeric membrane.

  13. Stopping power and energy loss cross section of a point charge penetrating through a dense medium of bound electrons

    International Nuclear Information System (INIS)

    Belkacem, A.; Sigmund, P.; Odense Univ.

    1989-01-01

    We have derived the dielectric function ε(k,ω) in the Lindhard approximation for a medium consisting of electrons individually bound by harmonic forces. The dielectric function is expressible in terms of a hypergeometric series and approaches well-known results in the limits of negligible binding, large momentum transfer, and long wavelength, respectively. The stopping power of a moving point charge scales very well with the shifted resonance frequency α 0 = (ω O 2 + ω P 2 ) 1/2 (ω O = oscillator frequency; ω P = plasma frequency) that follows from classical dispersion theory. The results differ noticeably from free-electron behavior even at rather high electron density. The discrete excitation levels of an isolated harmonic oscillator are increasingly shifted and broadened with increasing electron density. 15 refs., 2 figs

  14. UWB Filtering Power Divider with Two Narrow Notch-bands and Wide Stop-band

    Science.gov (United States)

    Wei, Feng; Wang, Xin-Yi; Zou, Xin Tong; Shi, Xiao Wei

    2017-12-01

    A compact filtering ultra-wideband (UWB) microstrip power divider (PD) with two sharply rejected notch-bands and wide stopband is analyzed and designed in this paper. The proposed UWB PD is based on a conventional Wilkinson power divider, while two stub loaded resonators (SLRs) are coupled into two symmetrical output ports to achieve a bandpass filtering response. The simplified composite right/left-handed (SCRLH) resonators are employed to generate the dual notched bands. Defected ground structure (DGS) is introduced to improve the passband performance. Good insertion/return losses, isolation and notch-band rejection are achieved as demonstrated in both simulation and experiment.

  15. Procedures for the selection of stopping power ratios for electron beams: Comparison of IAEA TRS procedures and of DIN procedures with Monte Carlo results

    International Nuclear Information System (INIS)

    Roos, M.; Christ, G.

    2000-01-01

    In the International Code of Practice IAEA TRS-381 the stopping power ratios water/air are selected according to the half-value depth and the depth of measurement. In the German Standard DIN 6800-2 a different procedure is recommended, which, in addition, takes the practical electron range into account; the stopping power data for monoenergetic beams from IAEA TRS-381 are used. Both procedures are compared with recent Monte Carlo calculations carried out for various beams of clinical accelerators. It is found that the DIN procedure shows a slightly better agreement. In addition, the stopping power ratios in IAEA TRS-381 are compared with those in DIN 6800-2 for the reference conditions of the beams from the PTB linac; the maximum deviation is not larger than 0.6%. (author)

  16. Self-Powered, One-Stop, and Multifunctional Implantable Triboelectric Active Sensor for Real-Time Biomedical Monitoring.

    Science.gov (United States)

    Ma, Ye; Zheng, Qiang; Liu, Yang; Shi, Bojin; Xue, Xiang; Ji, Weiping; Liu, Zhuo; Jin, Yiming; Zou, Yang; An, Zhao; Zhang, Wei; Wang, Xinxin; Jiang, Wen; Xu, Zhiyun; Wang, Zhong Lin; Li, Zhou; Zhang, Hao

    2016-10-12

    Operation time of implantable electronic devices is largely constrained by the lifetime of batteries, which have to be replaced periodically by surgical procedures once exhausted, causing physical and mental suffering to patients and increasing healthcare costs. Besides the efficient scavenging of the mechanical energy of internal organs, this study proposes a self-powered, flexible, and one-stop implantable triboelectric active sensor (iTEAS) that can provide continuous monitoring of multiple physiological and pathological signs. As demonstrated in human-scale animals, the device can monitor heart rates, reaching an accuracy of ∼99%. Cardiac arrhythmias such as atrial fibrillation and ventricular premature contraction can be detected in real-time. Furthermore, a novel method of monitoring respiratory rates and phases is established by analyzing variations of the output peaks of the iTEAS. Blood pressure can be independently estimated and the velocity of blood flow calculated with the aid of a separate arterial pressure catheter. With the core-shell packaging strategy, monitoring functionality remains excellent during 72 h after closure of the chest. The in vivo biocompatibility of the device is examined after 2 weeks of implantation, proving suitability for practical use. As a multifunctional biomedical monitor that is exempt from needing an external power supply, the proposed iTEAS holds great potential in the future of the healthcare industry.

  17. Accurate stopping power determination of 15N ions for hydrogen depth profiling by a combination of ion beams and synchrotron radiation

    Science.gov (United States)

    Zier, M.; Reinholz, U.; Riesemeier, H.; Radtke, M.; Munnik, F.

    2012-02-01

    Hydrogen analysis is of particular importance in thin film technology and it is often necessary to obtain a depth profile. The method with the best depth resolution is NRA using the 6385 keV resonance of the 1H( 15N,αγ) 12C nuclear reaction. The correct quantification of the depth and concentration scales in the measured hydrogen profiles relies on accurate stopping power values. We present a method to deduce these values from a combination of two techniques: NRA and X-ray reflectometry (XRR). This method is applied to the determination of the stopping power of ˜6.4 MeV 15N ions in H-containing amorphous Si-layers (a-Si:H). Density-independent stopping powers at different H concentrations are determined by combining the results from NRA and XRR with an overall uncertainty of 3.3%, showing good agreement with SRIM values. This work shows exemplary the methodology for future evaluation of stopping powers for quality assurance in NRA.

  18. Experimental verification of stopping-power prediction from single- and dual-energy computed tomography in biological tissues

    Science.gov (United States)

    Möhler, Christian; Russ, Tom; Wohlfahrt, Patrick; Elter, Alina; Runz, Armin; Richter, Christian; Greilich, Steffen

    2018-01-01

    An experimental setup for consecutive measurement of ion and x-ray absorption in tissue or other materials is introduced. With this setup using a 3D-printed sample container, the reference stopping-power ratio (SPR) of materials can be measured with an uncertainty of below 0.1%. A total of 65 porcine and bovine tissue samples were prepared for measurement, comprising five samples each of 13 tissue types representing about 80% of the total body mass (three different muscle and fatty tissues, liver, kidney, brain, heart, blood, lung and bone). Using a standard stoichiometric calibration for single-energy CT (SECT) as well as a state-of-the-art dual-energy CT (DECT) approach, SPR was predicted for all tissues and then compared to the measured reference. With the SECT approach, the SPRs of all tissues were predicted with a mean error of (-0.84  ±  0.12)% and a mean absolute error of (1.27  ±  0.12)%. In contrast, the DECT-based SPR predictions were overall consistent with the measured reference with a mean error of (-0.02  ±  0.15)% and a mean absolute error of (0.10  ±  0.15)%. Thus, in this study, the potential of DECT to decrease range uncertainty could be confirmed in biological tissue.

  19. SU-C-201-07: Towards Clinical Cherenkov Emission Dosimetry: Stopping Power-To-Cherenkov Power Ratios and Beam Quality Specification of Clinical Electron Beams

    International Nuclear Information System (INIS)

    Zlateva, Y; Seuntjens, J; El Naqa, I

    2016-01-01

    Purpose: We propose a Cherenkov emission (CE)-based reference dosimetry method, which in contrast to ionization chamber-based dosimetry, employs spectrum-averaged electron restricted mass collision stopping power-to-Cherenkov power ratios (SCRs), and we examine Monte Carlo-calculated SCRs and beam quality specification of clinical electron beams. Methods: The EGSnrc user code SPRRZnrc was modified to compute SCRs instead of stopping-power ratios (single medium: water; cut-off: CE threshold (observing Spencer-Attix conditions); CE power: Frank-Tamm). SCRs are calculated with BEAMnrc for realistic electron beams with nominal energies of 6–22 MeV from three Varian accelerators (TrueBeam Clinac 21EX, Clinac 2100C/D) and for mono-energetic beams of energies equal to the mean electron energy at the water surface. Sources of deviation between clinical and mono-energetic SCRs are analyzed quantitatively. A universal fit for the beam-quality index R_5_0 in terms of the depth of 50% CE C_5_0 is carried out. Results: SCRs at reference depth are overestimated by mono-energetic values by up to 0.2% for a 6-MeV beam and underestimated by up to 2.3% for a 22-MeV beam. The variation is mainly due to the clinical beam spectrum and photon contamination. Beam angular spread has a small effect across all depths and energies. The influence of the electron spectrum becomes increasingly significant at large depths, while at shallow depths and high beam energies photon contamination is predominant (up to 2.0%). The universal data fit reveals a strong linear correlation between R_5_0 and C_5_0 (ρ > 0.99999). Conclusion: CE is inherent to radiotherapy beams and can be detected outside the beam with available optical technologies, which makes it an ideal candidate for out-of-beam high-resolution 3D dosimetry. Successful clinical implementation of CE dosimetry hinges on the development of robust protocols for converting measured CE to radiation dose. Our findings constitute a key step

  20. TU-FG-BRB-03: Basis Vector Model Based Method for Proton Stopping Power Estimation From Experimental Dual Energy CT Data

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, S; Politte, D; O’Sullivan, J [Washington University in St. Louis, St. Louis, MO (United States); Han, D; Porras-Chaverri, M; Williamson, J [Virginia Commonwealth University, Richmond, VA (United States); Whiting, B [University of Pittsburgh, Pittsburgh, PA (United States)

    2016-06-15

    Purpose: This work aims at reducing the uncertainty in proton stopping power (SP) estimation by a novel combination of a linear, separable basis vector model (BVM) for stopping power calculation (Med Phys 43:600) and a statistical, model-based dual-energy CT (DECT) image reconstruction algorithm (TMI 35:685). The method was applied to experimental data. Methods: BVM assumes the photon attenuation coefficients, electron densities, and mean excitation energies (I-values) of unknown materials can be approximated by a combination of the corresponding quantities of two reference materials. The DECT projection data for a phantom with 5 different known materials was collected on a Philips Brilliance scanner using two scans at 90 kVp and 140 kVp. The line integral alternating minimization (LIAM) algorithm was used to recover the two BVM coefficient images using the measured source spectra. The proton stopping powers are then estimated from the Bethe-Bloch equation using electron densities and I-values derived from the BVM coefficients. The proton stopping powers and proton ranges for the phantom materials estimated via our BVM based DECT method are compared to ICRU reference values and a post-processing DECT analysis (Yang PMB 55:1343) applied to vendorreconstructed images using the Torikoshi parametric fit model (tPFM). Results: For the phantom materials, the average stopping power estimations for 175 MeV protons derived from our method are within 1% of the ICRU reference values (except for Teflon with a 1.48% error), with an average standard deviation of 0.46% over pixels. The resultant proton ranges agree with the reference values within 2 mm. Conclusion: Our principled DECT iterative reconstruction algorithm, incorporating optimal beam hardening and scatter corrections, in conjunction with a simple linear BVM model, achieves more accurate and robust proton stopping power maps than the post-processing, nonlinear tPFM based DECT analysis applied to conventional

  1. Comprehensive analysis of proton range uncertainties related to patient stopping-power-ratio estimation using the stoichiometric calibration

    Science.gov (United States)

    Yang, Ming; Zhu, X. Ronald; Park, Peter C.; Titt, Uwe; Mohan, Radhe; Virshup, Gary; Clayton, James E.; Dong, Lei

    2012-07-01

    The purpose of this study was to analyze factors affecting proton stopping-power-ratio (SPR) estimations and range uncertainties in proton therapy planning using the standard stoichiometric calibration. The SPR uncertainties were grouped into five categories according to their origins and then estimated based on previously published reports or measurements. For the first time, the impact of tissue composition variations on SPR estimation was assessed and the uncertainty estimates of each category were determined for low-density (lung), soft, and high-density (bone) tissues. A composite, 95th percentile water-equivalent-thickness uncertainty was calculated from multiple beam directions in 15 patients with various types of cancer undergoing proton therapy. The SPR uncertainties (1σ) were quite different (ranging from 1.6% to 5.0%) in different tissue groups, although the final combined uncertainty (95th percentile) for different treatment sites was fairly consistent at 3.0-3.4%, primarily because soft tissue is the dominant tissue type in the human body. The dominant contributing factor for uncertainties in soft tissues was the degeneracy of Hounsfield numbers in the presence of tissue composition variations. To reduce the overall uncertainties in SPR estimation, the use of dual-energy computed tomography is suggested. The values recommended in this study based on typical treatment sites and a small group of patients roughly agree with the commonly referenced value (3.5%) used for margin design. By using tissue-specific range uncertainties, one could estimate the beam-specific range margin by accounting for different types and amounts of tissues along a beam, which may allow for customization of range uncertainty for each beam direction.

  2. Range-energy relations and stopping power of water, water vapour and tissue equivalent liquid for α particles over the energy range 0.5 to 8 MeV

    International Nuclear Information System (INIS)

    Palmer, R.B.J.; Akhavan-Rezayat, Ahmad

    1978-01-01

    Experimental range-energy relations are presented for alpha particles in water, water vapour and tissue equivalent liquid at energies up to 8 MeV. From these relations differential stopping powers are derived at 0.25 MeV energy intervals. Consideration is given to sources of error in the range-energy measurements and to the uncertainties that these will introduce into the stopping power values. The ratio of the differential stopping power of muscle equivalent liquid to that of water over the energy range 0.5 to 7.5 MeV is discussed in relation to the specific gravity and chemical composition of the muscle equivalent liquid. Theoretical molecular stopping power calculations based upon the Bethe formula are also presented for water. The effect of phase upon the stopping power of water is discussed. The molecular stopping power of water vapour is shown to be significantly higher than that of water for energies below 1.25 MeV and above 2.5 MeV, the ratio of the two stopping powers rising to 1.39 at 0.5 MeV and to 1.13 at 7.0 MeV. Stopping power measurements for other liquids and vapours are compared with the results for water and water vapour and some are observed to have stopping power ratios in the vapour and liquid phases which vary with energy in a similar way to water. It is suggested that there may be several factors contributing to the increased stopping power of liquids. The need for further experimental results on a wider range of liquids is stressed

  3. Mean free paths by inelastic interactions, stopping powers, and energy straggling for electrons of energies up to 20 keV in various solids

    International Nuclear Information System (INIS)

    Akkerman, A.F.; Chernov, G.Ya.

    1978-01-01

    For the elements C, Be, Mg, Al, Si, K, Ge, Sb, Bi calculations of the mean free paths and stopping powers of low energy electrons are performed. In the computational model Lindhard's formalism of the dielectric response function for pair and plasmon excitation and the classical cross-section for ionization processes are used. Anomalously high mean free paths and small stopping powers in potassium are found. This behaviour which is connected with low electron concentration in the valence band is expected to hold for all alkali metals. For energies above 10 keV the calculated dE/dx agree well with values calculated from the Bethe-Bloch formula. A Monte-Carlo method is used for the calculation of the energy loss distribution of electrons passing through thin targets. It is noted that Blunck-Leisegang's theory fails to render the energy straggling at electron energies below 10 keV. (author)

  4. Stopping powers of havar and effective charge for 1.4-3.2 MeV/u {sup 127}I-ions

    Energy Technology Data Exchange (ETDEWEB)

    Alanko, T. E-mail: tommi.alanko@phys.jyu.fi; Hyvoenen, J.; Kylloenen, V.; Raeisaenen, J.; Virtanen, A

    2000-06-01

    Stopping powers of havar for 1.4-3.2 MeV/u {sup 127}I-ions have been determined by the transmission technique using two geometrical arrangements. No previous data have been published for havar with this ion. The experimental data are compared with predictions obtained by using Bragg's additivity rule with various parametrizations of the stopping power found in the literature. The values obtained by the parametrizations underestimate the experimental data by 5-11%. The empirical correction scheme of Thwaites yields values in rather good agreement with the present results, especially at energies above 1.9 MeV/u. The effective charges of the {sup 127}I ions were also deduced from the experimental data.

  5. The precision of proton range calculations in proton radiotherapy treatment planning: experimental verification of the relation between CT-HU and proton stopping power

    International Nuclear Information System (INIS)

    Schaffner, B.; Pedroni, E.

    1998-01-01

    The precision in proton radiotherapy treatment planning depends on the accuracy of the information used to calculate the stopping power properties of the tissues in the patient's body. This information is obtained from computed tomography (CT) images using a calibration curve to convert CT Hounsfield units into relative proton stopping power values. The validity of a stoichiometric method to create the calibration curve has been verified by measuring pairs of Hounsfield units and stopping power values for animal tissue samples. It was found that the agreement between measurement and calibration curve is better than 1% if beam hardening effects in the acquisition of the CT images can be neglected. The influence of beam hardening effects on the quantitative reading of the CT measurements is discussed and an estimation for the overall range precision of proton beams is given. It is expected that the range of protons in the human body can be controlled to better than ±1.1% of the water equivalent range in soft tissue and ±1.8% in bone, which translates into a range precision of about 1-3 mm in typical treatment situations. (author)

  6. Experimental study of ion stopping power in warm dense matter: charge-state distribution measurements of ions leaving warm dense matter

    International Nuclear Information System (INIS)

    Gauthier, Maxence

    2013-01-01

    The determination if the ion slowing down process (or stopping power) in warm dense matter is essential especially in the frame of inertial confinement fusion. During my thesis, our interest was driven by the modification of the charge state of ion beam emerging from warm dense matter, this quantity playing a major role in ion stopping power calculation. We took advantage of the properties exhibited by ion beams produced by high intensity short pulse lasers to study during two experiments performed at ELFIE and TITAN facilities, the charge state modification of a carbon and helium ion beams emerging from an aluminum foil isochorically heated by an energetic proton beam. In the first two chapters are presented the major challenges regarding the subject from both a theoretical and experimental point of view. Here are exposed the different simulation tools used during the thesis. The third chapter is devoted to the study of the property of laser-produced ion beams in the scope of our experiments aiming at studying the stopping power. We have studied in particular ion beams generated using lower-than-solid density targets during two experiments: helium gas jet and laser-exploded target. In the last chapter are presented the set-ups and results of the two experiments on the charge state of ion beam emerging from warm dense matter. The data we measured in solid-density cold aluminum are successfully compared with the results already obtained in conventional accelerators. (author) [fr

  7. Stopping powers of havar for 1.6, 2.3 and 3.2 MeV/u heavy ions

    Energy Technology Data Exchange (ETDEWEB)

    Alanko, T. E-mail: tommi.alanko@phys.jyu.fi; Hyvoenen, J.; Kylloenen, V.; Raeisaenen, J.; Virtanen, A

    2000-03-01

    Stopping powers of havar for {sup 28,30}Si-, {sup 36}Ar-, {sup 54,56}Fe- and {sup 80,84}Kr-ions with energies of 1.6, 2.3 and 3.2 MeV/u have been determined by a transmission technique. Sample foils are exposed to the direct beams. No previous data for havar with these ions have been published. The obtained results are brought together with literature havar data for {sup 1}H-, {sup 4}He-, {sup 7}Li-, {sup 11}B-, {sup 12}C-, {sup 14}N-, {sup 16}O- and {sup 127}I-ions at the same ion velocity. The experimental data are compared with the values predicted by the SRIM-2000 parametrization using Bragg's rule. A systematic underestimation, by 6-23%, of the experimental stopping powers was observed. The empirical correction scheme of Thwaites has been applied to the stopping power values obtained by the parametrization. The corrected values agree well with the present results. Also, the effective charge values of the various ions were deduced from the experimental set of data.

  8. Polycarbonate, Mylar and Havar stopping powers for 1.0-3.25 MeV/nucleon {sup 40}Ar-ions

    Energy Technology Data Exchange (ETDEWEB)

    Alanko, T. [Department of Physics, University of Jyvaeskylae, Jyvaeskylae (Finland)]. E-mail: tommi.alanko@phys.jyu.fi; Hyvoenen, J.; Kylloenen, V.; Laitinen, P.; Matilainen, A.; Raeisaenen, J.; Virtanen, A. [Department of Physics, University of Jyvaeskylae, Jyvaeskylae (Finland)

    2001-12-03

    Stopping powers of polycarbonate, Mylar and Havar for 1.0-3.25 MeV/nucleon {sup 40}Ar-ions have been determined by the transmission method in two geometries. The stopping power values were obtained within uncertainty of 2.1-4.5% for the various materials. The present results are compared with the predictions obtained by the most commonly used procedures employed in obtaining stopping powers. These include the Northcliffe and Schilling model, semi-empirical parametrization of Ziegler et al (SRIM2000) with and without the cores and bonds model and the Hubert et al formulation. SRIM2000 values were in good agreement in case of Mylar and Havar, on average within 3% of present results. For polycarbonate the differences were less than 6% on average. The cores and bonds (CAB) model improved the parametrization values slightly. The Northcliffe and Schilling model and the Hubert et al formulation both yielded values within 5% or less for Mylar and polycarbonate. For the Havar the Hubert et al formulation and the present results disagreed by 10% on average. (author)

  9. SU-F-J-195: On the Performance of Four Dual Energy CT Formalisms for Extracting Proton Stopping Powers

    Energy Technology Data Exchange (ETDEWEB)

    Baer, E; Royle, G [University College London, London (United Kingdom); Lalonde, A; Bouchard, H [University of Montreal, Montreal, QC (Canada)

    2016-06-15

    Purpose: Dual energy CT can predict stopping power ratios (SPR) for ion therapy treatment planning. Several approaches have been proposed recently, however accuracy and practicability in a clinical workflow are unaddressed. The aim of this work is to provide a fair comparison of available approaches in a human-like phantom to find the optimal method for tissue characterization in a clinical situation. Methods: The SPR determination accuracy is investigated using simulated DECT images. A virtual human-like phantom is created containing 14 different standard human tissues. SECT (120 kV) and DECT images (100 kV and 140 kV Sn) are simulated using the software ImaSim. The single energy CT (SECT) stoichiometric calibration method and four recently published calibration-based DECT methods are implemented and used to predict the SPRs from simulated images. The difference between SPR predictions and theoretical SPR are compared pixelwize. Mean, standard deviation and skewness of the SPR difference distributions are used as measures for bias, dispersion and symmetry. Results: The average SPR differences and standard deviations are (0.22 ± 1.27)% for SECT, and A) (−0.26 ± 1.30)%, B) (0.08 ± 1.12)%, C) (0.06 ± 1.15)% and D) (−0.05 ± 1.05)% for the four DECT methods. While SPR prediction using SECT is showing a systematic error on SPR, the DECT methods B, C and D are unbiased. The skewness of the SECT distribution is 0.57%, and A) −0.19%, B) −0.56%, C) −0.29% and D) −0.07% for DECT methods respectively. Conclusion: The here presented DECT methods B, C and D outperform the commonly used SECT stoichiometric calibration. These methods predict SPR accurately without a bias and within ± 1.2% (68th percentile). This indicates that DECT potentially improves accuracy of range predictions in proton therapy. A validation of these findings using clinical CT images of real tissues is necessary.

  10. Comparison of x ray computed tomography number to proton relative linear stopping power conversion functions using a standard phantom.

    Science.gov (United States)

    Moyers, M F

    2014-06-01

    Adequate evaluation of the results from multi-institutional trials involving light ion beam treatments requires consideration of the planning margins applied to both targets and organs at risk. A major uncertainty that affects the size of these margins is the conversion of x ray computed tomography numbers (XCTNs) to relative linear stopping powers (RLSPs). Various facilities engaged in multi-institutional clinical trials involving proton beams have been applying significantly different margins in their patient planning. This study was performed to determine the variance in the conversion functions used at proton facilities in the U.S.A. wishing to participate in National Cancer Institute sponsored clinical trials. A simplified method of determining the conversion function was developed using a standard phantom containing only water and aluminum. The new method was based on the premise that all scanners have their XCTNs for air and water calibrated daily to constant values but that the XCTNs for high density/high atomic number materials are variable with different scanning conditions. The standard phantom was taken to 10 different proton facilities and scanned with the local protocols resulting in 14 derived conversion functions which were compared to the conversion functions used at the local facilities. For tissues within ±300 XCTN of water, all facility functions produced converted RLSP values within ±6% of the values produced by the standard function and within 8% of the values from any other facility's function. For XCTNs corresponding to lung tissue, converted RLSP values differed by as great as ±8% from the standard and up to 16% from the values of other facilities. For XCTNs corresponding to low-density immobilization foam, the maximum to minimum values differed by as much as 40%. The new method greatly simplifies determination of the conversion function, reduces ambiguity, and in the future could promote standardization between facilities. Although it

  11. TU-FG-BRB-01: Dual Energy CT Proton Stopping Power Ratio Calibration and Validation with Animal Tissues

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Y; Yin, L; Ainsley, C; McDonough, J; Solberg, T; Lin, A; Teo, B [University of Pennsylvania, Philadelphia, PA (United States)

    2016-06-15

    Purpose: The conversion of Hounsfield Unit (HU) to proton stopping power ratio (SPR) is a main source of uncertainty in proton therapy. In this study, the SPRs of animal tissues were measured and compared with prediction from dual energy CT (DECT) and single energy CT (SECT) calibrations. Methods: A stoichiometric calibration method for DECT was applied to predict the SPR using CT images acquired at 80 kVp and 140 kVp. The dual energy index was derived based on the HUs of the paired spectral images and used to calculate the SPRs of the materials. Tissue surrogates with known chemical compositions were used for calibration, and animal tissues (pig brain, liver, kidney; veal shank, muscle) were used for validation. The materials were irradiated with proton pencil beams, and SPRs were deduced from the residual proton range measured using a multi-layer ion chamber device. In addition, Gafchromic EBT3 films were used to measure the distal dose profiles after irradiation through the tissue samples and compared with those calculated by the treatment planning system using both DECT and SECT predicted SPRs. Results: The differences in SPR between DECT prediction and measurement were −0.31±0.36% for bone, 0.47±0.42% for brain, 0.67±0.15% for liver, 0.51±0.52% for kidney, and −0.96±0.15% for muscle. The corresponding results using SECT were 3.1±0.12%, 1.90±0.45%, −0.66±0.11%, 2.33±0.21%, and −1.70±0.17%. In the film measurements, average distances between film and calculated distal dose profiles were 0.35±0.12 mm for DECT calibration and −1.22±0.12 mm for SECT calibration for a beam with a range of 15.79 cm. Conclusion: Our study indicates that DECT is superior to SECT for proton SPR prediction and has the potential to reduce the range uncertainty to less than 2%. DECT may permit the use of tighter distal and proximal range uncertainty margins for treatment, thereby increasing the precision of proton therapy.

  12. Measurements of output factors with different detector types and Monte Carlo calculations of stopping-power ratios for degraded electron beams

    International Nuclear Information System (INIS)

    Bjoerk, Peter; Knoeoes, Tommy; Nilsson, Per

    2004-01-01

    The aim of the present study was to investigate three different detector types (a parallel-plate ionization chamber, a p-type silicon diode and a diamond detector) with regard to output factor measurements in degraded electron beams, such as those encountered in small-electron-field radiotherapy and intraoperative radiation therapy (IORT). The Monte Carlo method was used to calculate mass collision stopping-power ratios between water and the different detector materials for these complex electron beams (nominal energies of 6, 12 and 20 MeV). The diamond detector was shown to exhibit excellent properties for output factor measurements in degraded beams and was therefore used as a reference. The diode detector was found to be well suited for practical measurements of output factors, although the water-to-silicon stopping-power ratio was shown to vary slightly with treatment set-up and irradiation depth (especially for lower electron energies). Application of ionization-chamber-based dosimetry, according to international dosimetry protocols, will introduce uncertainties smaller than 0.3% into the output factor determination for conventional IORT beams if the variation of the water-to-air stopping-power ratio is not taken into account. The IORT system at our department includes a 0.3 cm thin plastic scatterer inside the therapeutic beam, which furthermore increases the energy degradation of the electrons. By ignoring the change in the water-to-air stopping-power ratio due to this scatterer, the output factor could be underestimated by up to 1.3%. This was verified by the measurements. In small-electron-beam dosimetry, the water-to-air stopping-power ratio variation with field size could mostly be ignored. For fields with flat lateral dose profiles (>3 x 3 cm 2 ), output factors determined with the ionization chamber were found to be in close agreement with the results of the diamond detector. For smaller field sizes the lateral extension of the ionization chamber

  13. Measurements of output factors with different detector types and Monte Carlo calculations of stopping-power ratios for degraded electron beams.

    Science.gov (United States)

    Björk, Peter; Knöös, Tommy; Nilsson, Per

    2004-10-07

    The aim of the present study was to investigate three different detector types (a parallel-plate ionization chamber, a p-type silicon diode and a diamond detector) with regard to output factor measurements in degraded electron beams, such as those encountered in small-electron-field radiotherapy and intraoperative radiation therapy (IORT). The Monte Carlo method was used to calculate mass collision stopping-power ratios between water and the different detector materials for these complex electron beams (nominal energies of 6, 12 and 20 MeV). The diamond detector was shown to exhibit excellent properties for output factor measurements in degraded beams and was therefore used as a reference. The diode detector was found to be well suited for practical measurements of output factors, although the water-to-silicon stopping-power ratio was shown to vary slightly with treatment set-up and irradiation depth (especially for lower electron energies). Application of ionization-chamber-based dosimetry, according to international dosimetry protocols, will introduce uncertainties smaller than 0.3% into the output factor determination for conventional IORT beams if the variation of the water-to-air stopping-power ratio is not taken into account. The IORT system at our department includes a 0.3 cm thin plastic scatterer inside the therapeutic beam, which furthermore increases the energy degradation of the electrons. By ignoring the change in the water-to-air stopping-power ratio due to this scatterer, the output factor could be underestimated by up to 1.3%. This was verified by the measurements. In small-electron-beam dosimetry, the water-to-air stopping-power ratio variation with field size could mostly be ignored. For fields with flat lateral dose profiles (>3 x 3 cm2), output factors determined with the ionization chamber were found to be in close agreement with the results of the diamond detector. For smaller field sizes the lateral extension of the ionization chamber hampers

  14. Hydrogen/oxygen injection stopping method for nuclear power plant and emergent hydrogen/oxygen injection device

    International Nuclear Information System (INIS)

    Ishida, Ryoichi; Ota, Masamoto; Takagi, Jun-ichi; Hirose, Yuki

    1998-01-01

    The present invention provides a device for suppressing increase of electroconductivity of reactor water during operation of a BWR type reactor, upon occurrence of reactor scram of the plant or upon stopping of hydrogen/oxygen injection due to emergent stoppage of an injection device so as not to deteriorate the integrity of a gas waste processing system upon occurrence of scram. Namely, when injection of hydrogen/oxygen is stopped during plant operation, the injection amount of hydrogen is reduced gradually. Subsequently, injection of hydrogen is stopped. With such procedures, the increase of electroconductivity of reactor water can be suppressed upon stoppage of hydrogen injection. When injection of hydrogen/oxygen is stopped upon shut down of the plant, the amount of hydrogen injection is changed depending on the change of the feedwater flow rate, and then the plant is shut down while keeping hydrogen concentration of feedwater to a predetermined value. With such procedures, increase of the reactor water electroconductivity can be suppressed upon stoppage of hydrogen injection. Upon emergent stoppage of the hydrogen/oxygen injection device, an emergent hydrogen/oxygen injection device is actuated to continue the injection of hydrogen/oxygen. With such procedures, elevation of reactor water electroconductivity can be suppressed. (I.S.)

  15. Atomic stopping-power problems encountered in measurements of nuclear γ-ray lifetimes by the Doppler-shift-attenuation method

    International Nuclear Information System (INIS)

    Latta, B.M.; Scanlon, P.J.

    1976-01-01

    The value of the nuclear lifetime of the 3.34-MeV level in 22 Ne as determined by Broude et al. by the Doppler shift attenuation method exhibits variations depending on the atomic number Z 2 of the slowing down medium. The lifetime has been re-evaluated within the framework of the Lindhard-Winther stopping theory, assuming a simple approximate form for the density of electrons associated with an atom in a solid and an effective point charge for the projectile based on experimental stopping powers. Although there are still variations in the value of the lifetime the variations appear to be systematic through the region of the transition elements. (Auth.)

  16. SU-F-T-136: Breath Hold Lung Phantom Study in Using CT Density Versus Relative Stopping Power Ratio for Proton Pencil Beam Scanning System

    Energy Technology Data Exchange (ETDEWEB)

    Syh, J; Wu, H; Rosen, L [Willis-Knighton Medical Center, Shreveport, LA (United States)

    2016-06-15

    Purpose: To evaluate mass density effects of CT conversion table and its variation in current treatment planning system of spot scanning proton beam using an IROC proton lung phantom for this study. Methods: A proton lung phantom study was acquired to Imaging and Radiation Oncology Core Houston (IROC) Quality Assurance Center. Inside the lung phantom, GAF Chromic films and couples of thermal luminescent dosimeter (TLD) capsules embedded in specified PTV and adjacent structures to monitor delivered dosage and 3D dose distribution profiles. Various material such as cork (Lung), blue water (heart), Techron HPV (ribs) and organic material of balsa wood and cork as dosimetry inserts within phantom of solid water (soft tissue). Relative stopping power (RLSP) values were provided. Our treatment planning system (TPS) doesn’t require SP instead relative density was converted relative to water. However lung phantom was irradiated by planning with density override and the results were compared with IROC measurements. The second attempt was conducted without density override and compared with IROC’s. Results: The higher passing rate of imaging and measurement results of the lung phantom irradiation met the criteria by IROC without density override. The film at coronal plane was found to be shift due to inclined cylinder insertion. The converted CT density worked as expected to correlate relative stopping power. Conclusion: The proton lung phantom provided by IROC is a useful tool to qualify our commissioned proton pencil beam delivery with TPS within reliable confidence. The relative mass stopping power ratios of materials were converted from the relative physical density relative to water and the results were satisfied.

  17. Interaction of antiprotons with Rb atoms and a comparison of antiproton stopping powers of the atoms H, Li, Na, K, and Rb

    DEFF Research Database (Denmark)

    Lühr, Armin Christian; Fischer, Nicolas; Saenz, Alejandro

    2009-01-01

    Ionization and excitation cross sections as well as electron-energy spectra and stopping powers of the alkali metal atoms Li, Na, K, and Rb colliding with antiprotons were calculated using a time-dependent channel-coupling approach. An impact-energy range from 0.25 to 4000 keV was considered....... The target atoms are treated as effective one-electron systems using a model potential. The results are compared with calculated cross sections for antiproton-hydrogen atom collisions....

  18. New experimental stopping power data of 4He, 16O, 40Ar, 48Ca and 84Kr projectiles in different solid materials

    Science.gov (United States)

    Trzaska, W. H.; Knyazheva, G. N.; Perkowski, J.; Andrzejewski, J.; Khlebnikov, S. V.; Kozulin, E. M.; Malkiewicz, T.; Mutterer, M.; Savelieva, E. O.

    2018-03-01

    New experimental data on energy loss of 4He, 16O, 40Ar, 48Ca and 84Kr ions in thin, self-supporting foils of C, Al, Ni, Ag, Lu, Au, Pb and Th are presented. The measurements, using the TOF-E method, were done in a very broad energy range around the stopping power maximum; typically from 0.1 to 11 MeV/u. When available, the extracted stopping power values are compared with the previously published data. The overall agreement is good although a fair comparison is difficult as the covered energy range is much larger than in previous measurements. The small error bars and a broad coverage allowed us to test the predictions of theoretical codes: PASS, CasP, and semi-empirical programs: SRIM, LET, MSTAR, and the Hubert table predictions. The deviations of PASS predictions from the experimental data do not exceed 20% for all the measured combinations. CasP predictions are within 15% from the data for heavier ions but diverge up to 40% for lighter ions. Semi-empirical approaches, including SRIM, deviate from the experimental data by less than 5% for the regions already covered by previous experiments but err by about 10-20% for the ion/target combinations that were not measured before: Ca in Lu as well as Kr in Lu, Pb, and Th.

  19. A study of charge state approach to the stopping power of MeV B, N, and O ions in carbon

    International Nuclear Information System (INIS)

    Li, M.M.; O'Connor, D.J.; Timmers, H.; Dastoor, P.C.

    1999-01-01

    The charge state approach has been applied to treat the electronic stopping powers of swift O, N and B ions in carbon foil. According to the charge state model, the contributions to the electronic stopping power of energetic projectiles passing through solid targets are due to collisional interactions and from the charge exchange process. The definition of fractional effective charge from Brandt and Kitagawa has been combined into the current charge state model. Extensive applications of this approach require data of the equilibrium charge state distributions and knowledge of charge-exchange cross sections-involving electronic capture and loss processes. Both measured data and empirical calculations of the equilibrium charge state fraction are used in the study, and the electronic capture cross sections are obtained with the eikonal Brinkman-Kramers approximation (EBK). By comparing the numerical results with the latest experimental data as well as empirical values, it is shown that the present approach slightly overestimates the energy loss at the intermediate velocity region

  20. Stop Ticks

    Science.gov (United States)

    ... PDF file Microsoft PowerPoint file Microsoft Word file Microsoft ... Center for Emerging and Zoonotic Infectious Diseases Page maintained by: Office of the Associate Director for Communication, Digital Media ...

  1. Measurement of the stopping power of water for carbon ions in the energy range of 1 MeV-6 MeV using the inverted Doppler-shift attenuation method

    Energy Technology Data Exchange (ETDEWEB)

    Rahm, Johannes Martin

    2016-10-31

    Cancer therapy using carbon ions has gained increasing interest in the last decade due to its advantageous dose distributions. For the dosimetry and treatment planning, the accurate knowledge of the stopping power of water for carbon ions is of crucial importance. In the high energy region, the stopping power can be calculated rather accurately by means of the Bethe-Bloch formula. In the case of projectile velocities comparable to those of the valence electrons of the target, these calculations are subject to large uncertainties. There exist no experimental data for the stopping power of water for projectile energies prevailing in the so-called Bragg peak region. The currently available stopping power data for water are derived from measurements in water vapour or D{sub 2}O ice and, hence, neglect the dependence on the state of aggregation. The stopping power of water for charged particles is of high interest not only for practical applications but also to consider how physical and chemical state of the target influence the collisional energy transfer. For the measurement of the stopping power of water, the inverted Doppler-shift attenuation method was used in this work. This method has the advantage that the projectile itself is not needed to be detected and can be slowed down entirely in the target. In this method, the stopping power is determined from the Doppler-shift of the gamma-quanta emitted by projectiles during their slow down. This experiment can be performed at atmospheric pressure and consequently, the stopping power of water can be measured in its real physiological condition. In this work, the stopping power of water for carbon ions was measured for the first time in the energy range between 1 MeV and 6 MeV covering the kinetic energies of carbon ions in the Bragg peak region. The experimental method is presented in detail along with the design of the apparatus and of the data acquisition system. A comprehensive analysis of instrumental effects

  2. Electronic stopping power of slow H{sup +} and He{sup 2+} ions in CdTe from first principle

    Energy Technology Data Exchange (ETDEWEB)

    Li, Chang-kai [The Key Laboratory of Beam Technology and Material Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Mao, Fei [School of Nuclear Science and Technology, University of South China, Hengyang 421001 (China); Fu, Yan-long; Liao, Bin [The Key Laboratory of Beam Technology and Material Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Ouyang, Xiao-ping [Northwest Institute of Nuclear Technology, Xi’an 710024 (China); Zhang, Feng-Shou, E-mail: fszhang@bnu.edu.cn [The Key Laboratory of Beam Technology and Material Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator of Lanzhou, Lanzhou 730000 (China)

    2017-02-01

    We study through time-dependent density-functional theory (TDDFT) method the electronic stopping power of low-energy protons and helium ions moving through CdTe under the condition of channeling. The agreement between our calculated results and SRIM data roughly up to the stopping maximum for the proton along the 〈1 0 0〉 and 〈1 1 1〉 crystalline axes and for helium ions along 〈1 0 0〉 crystalline axis is satisfactory, which can be explained by the energy transfer mechanism that electron–hole excitation caused by ions in the solid. However, in the channel of 〈1 1 1〉 for helium ions, a transition between two velocities regimes is observed at about v = 0.4 a.u. This may be an indication of extra energy loss channel beyond the electron–hole excitation. To analyze it, we calculate the amount of electrons captured by the moving projectiles in real time. It is found that the soft transition between two velocities regimes can be attributed to the charge transfer and charge resonance between helium ion and host atoms of CdTe crystal, which are considered as additional energy loss channels.

  3. A new calculation on the stopping power and mean free path for low energy electrons in toluene over energy range of 20-10 000 eV

    International Nuclear Information System (INIS)

    Tan Zhenyu; Xia Yueyuan; Liu Xiangdong; Zhao Mingwen; Zhang Liming

    2009-01-01

    A new calculation of the stopping powers (SP) and inelastic mean free paths (IMFP) for electrons in toluene at energies below 10 keV has been presented. The calculation is based on the dielectric model and on an empirical evaluation approach of optical energy loss function (OELF). The reliability for the evaluated OELFs of several hydrocarbons with available experimental optical data has been systematically checked. For toluene, using the empirical OELF, the evaluated mean ionization potential, is compared with that given by Bragg's rule, and the calculated SP at 10 keV is also compared with the Bethe-Bloch prediction. The present results for SP and IMFP provide an alternative basic data for the study on the energy deposition of low-energy electrons transport through toluene, and also show that the method used in this work may be a good one for evaluating the SP and IMFP for hydrocarbons

  4. Organic materials irradiated at very low temperature and at different stopping powers: examples of polyethylene and of cyclohexane molecules trapped in matrix

    International Nuclear Information System (INIS)

    Melot, M.

    2003-10-01

    This thesis concerns the formation mechanisms of defects created in organic materials during irradiation under vacuum, at very low temperature and at different electronic stopping powers. Analysis have been realised by infrared spectroscopy. The first part concerns polyethylene. Irradiating at 8 K allows to dissociate the direct irradiation effects (in cage reactions) and the radical recombination effects. According to the considered chemical groups, the radical mobility leads to very different changes for the formation radiochemical yields. The second part concerns the irradiation of cyclohexane molecules trapped in a solid argon matrix. We evaluate the contribution of intermolecular and intramolecular reactions. The intermolecular reactions have limited consequences when using low ionising radiations but are crucial for heavy ion irradiations. (author)

  5. SU-E-J-136: Investigation Into Robustness of Stopping Power Calculated by DECT and SECT for Proton Therapy Treatment Planning

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, J [University of Adelaide, Adelaide, SA (Australia); Penfold, S [University of Adelaide, Adelaide, SA (Australia); Royal Adelaide Hospital, Adelaide, SA (Australia)

    2015-06-15

    Purpose: To investigate the robustness of dual energy CT (DECT) and single energy CT (SECT) proton stopping power calibration techniques and quantify the associated errors when imaging a phantom differing in chemical composition to that used during stopping power calibration. Methods: The CIRS tissue substitute phantom was scanned in a CT-simulator at 90kV and 140kV. This image set was used to generate a DECT proton SPR calibration based on a relationship between effective atomic number and mean excitation energy. A SECT proton SPR calibration based only on Hounsfield units (HUs) was also generated. DECT and SECT scans of a second phantom of known density and chemical composition were performed. The SPR of the second phantom was calculated with the DECT approach (SPR-DECT),the SECT approach (SPR-SECT) and finally the known density and chemical composition of the phantom (SPR-ref). The DECT and SECT image sets were imported into the Pinnacle{sup 3} research release of proton therapy treatment planning. The difference in dose when exposed to a common pencil beam distribution was investigated. Results: SPR-DECT was found to be in better agreement with SPR-ref than SPR- SECT. The mean difference in SPR for all materials was 0.51% for DECT and 6.89% for SECT. With the exception of Teflon, SPR-DECT was found to agree with SPR-ref to within 1%. Significant differences in calculated dose were found when using the DECT image set or the SECT image set. Conclusion: The DECT calibration technique was found to be more robust to situations in which the physical properties of the test materials differed from the materials used during SPR calibration. Furthermore, it was demonstrated that the DECT and SECT SPR calibration techniques can Result in significantly different calculated dose distributions.

  6. SU-F-J-193: Efficient Dose Extinction Method for Water Equivalent Path Length (WEPL) of Real Tissue Samples for Validation of CT HU to Stopping Power Conversion

    International Nuclear Information System (INIS)

    Zhang, R; Baer, E; Jee, K; Sharp, G; Flanz, J; Lu, H

    2016-01-01

    Purpose: For proton therapy, an accurate model of CT HU to relative stopping power (RSP) conversion is essential. In current practice, validation of these models relies solely on measurements of tissue substitutes with standard compositions. Validation based on real tissue samples would be much more direct and can address variations between patients. This study intends to develop an efficient and accurate system based on the concept of dose extinction to measure WEPL and retrieve RSP in biological tissue in large number of types. Methods: A broad AP proton beam delivering a spread out Bragg peak (SOBP) is used to irradiate the samples with a Matrixx detector positioned immediately below. A water tank was placed on top of the samples, with the water level controllable in sub-millimeter by a remotely controlled dosing pump. While gradually lowering the water level with beam on, the transmission dose was recorded at 1 frame/sec. The WEPL were determined as the difference between the known beam range of the delivered SOBP (80%) and the water level corresponding to 80% of measured dose profiles in time. A Gammex 467 phantom was used to test the system and various types of biological tissue was measured. Results: RSP for all Gammex inserts, expect the one made with lung-450 material (<2% error), were determined within ±0.5% error. Depends on the WEPL of investigated phantom, a measurement takes around 10 min, which can be accelerated by a faster pump. Conclusion: Based on the concept of dose extinction, a system was explored to measure WEPL efficiently and accurately for a large number of samples. This allows the validation of CT HU to stopping power conversions based on large number of samples and real tissues. It also allows the assessment of beam uncertainties due to variations over patients, which issue has never been sufficiently studied before.

  7. SU-F-J-193: Efficient Dose Extinction Method for Water Equivalent Path Length (WEPL) of Real Tissue Samples for Validation of CT HU to Stopping Power Conversion

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, R; Baer, E; Jee, K; Sharp, G; Flanz, J; Lu, H [Massachusetts General Hospital and Harvard Medical School, Boston, MA (United States)

    2016-06-15

    Purpose: For proton therapy, an accurate model of CT HU to relative stopping power (RSP) conversion is essential. In current practice, validation of these models relies solely on measurements of tissue substitutes with standard compositions. Validation based on real tissue samples would be much more direct and can address variations between patients. This study intends to develop an efficient and accurate system based on the concept of dose extinction to measure WEPL and retrieve RSP in biological tissue in large number of types. Methods: A broad AP proton beam delivering a spread out Bragg peak (SOBP) is used to irradiate the samples with a Matrixx detector positioned immediately below. A water tank was placed on top of the samples, with the water level controllable in sub-millimeter by a remotely controlled dosing pump. While gradually lowering the water level with beam on, the transmission dose was recorded at 1 frame/sec. The WEPL were determined as the difference between the known beam range of the delivered SOBP (80%) and the water level corresponding to 80% of measured dose profiles in time. A Gammex 467 phantom was used to test the system and various types of biological tissue was measured. Results: RSP for all Gammex inserts, expect the one made with lung-450 material (<2% error), were determined within ±0.5% error. Depends on the WEPL of investigated phantom, a measurement takes around 10 min, which can be accelerated by a faster pump. Conclusion: Based on the concept of dose extinction, a system was explored to measure WEPL efficiently and accurately for a large number of samples. This allows the validation of CT HU to stopping power conversions based on large number of samples and real tissues. It also allows the assessment of beam uncertainties due to variations over patients, which issue has never been sufficiently studied before.

  8. Misconceptions impairing the validity of the stopping power tables in the SRIM library and suggestions for doing better in the future

    Science.gov (United States)

    Wittmaack, Klaus

    2016-08-01

    inconsistently from the predictions of Lindhard-Scharff (LS) theory; they also exhibit various forms of exotic velocity dependence. These deviations are primarily due to the fact that the range of validity of BB theory is artificially extended to velocities at which the 'effective-charge' concept is assumed to be applicable. Coupled Z1,2 scaling as in theories of LS or Firsov would be much more appropriate. Overall, the electronic stopping cross sections by SRIM are of unpredictable value and often strongly misleading below 1 MeV/u. (iv) Another consequence of the tight link to the Z1,2 dependence of BB theory is that only 2 × 92 master sets of electronic stopping cross sections were required to generate all conceivable 89 × 92 tables from Se,f-ratios for elemental targets (the tables for H, He and Li projectiles are derived separately). The information contained in the SRIM library at large thus exhibits a highly redundant character. (v) The nuclear stopping cross sections Sn mirror the predictions of the universal potential due by Ziegler, Biersack and Littmark, which differ from alternative suggestions typically by less than 15%. With this uncertainty, range distributions may be calculated with the TRIM program of SRIM, but only at energies where Sn dominates so that uncertainties in Se play a minor role. (vi) As a side aspect, an example is presented illustrating the efforts required to identify incorrect experimental data, notably when respected authors are accountable. (vii) Other approaches to establish stopping power tables are shown to be subject to the same problems as SRIM. It is recommended to add a warning to all theses tables, informing users at which energies the data are likely to lack reliability. (viii) The currently unacceptable quality of Se,f-data below 1 MeV/u could be improved significantly in the future if the user friendly TRIM(SRIM) code were modified to allow simulations with a free choice of nuclear and electronic stopping cross sections

  9. Stopping powers from the inverted doppler shift attenuation method: Z-oscillations; Bragg's rule or chemical effects; solid and liquid state effects

    International Nuclear Information System (INIS)

    Pietsch, W.; Hauser, U.; Neuwirth, W.

    1976-01-01

    With the 'Inverted Doppler Shift Attenuation (IDSA)' method stopping cross sections for swift ions can be measured with an accuracy of about 1%. Here results are reported with lithium and carbon projectiles in very different stopping materials. It turns out that the stopping cross section around Bohr's velocity is linearly dependent on the velocity. Stopping cross sections of elements show the expected Z 2 -oscillations. With compound targets strong deviations from Bragg's rule were found which means that the stopping cross section is influenced by the chemical bonding. In electrolytic solutions effects due to ion-dipole interactions can be observed. These phenomena demonstrate the strong sensitivity of electronic stopping cross sections on the specific distribution of the outer electrons of the target atoms. Further Lindhard's formula has been modified which gives a good description of this influence. (Auth.)

  10. Theoretical variance analysis of single- and dual-energy computed tomography methods for calculating proton stopping power ratios of biological tissues

    International Nuclear Information System (INIS)

    Yang, M; Zhu, X R; Mohan, R; Dong, L; Virshup, G; Clayton, J

    2010-01-01

    We discovered an empirical relationship between the logarithm of mean excitation energy (ln I m ) and the effective atomic number (EAN) of human tissues, which allows for computing patient-specific proton stopping power ratios (SPRs) using dual-energy CT (DECT) imaging. The accuracy of the DECT method was evaluated for 'standard' human tissues as well as their variance. The DECT method was compared to the existing standard clinical practice-a procedure introduced by Schneider et al at the Paul Scherrer Institute (the stoichiometric calibration method). In this simulation study, SPRs were derived from calculated CT numbers of known material compositions, rather than from measurement. For standard human tissues, both methods achieved good accuracy with the root-mean-square (RMS) error well below 1%. For human tissues with small perturbations from standard human tissue compositions, the DECT method was shown to be less sensitive than the stoichiometric calibration method. The RMS error remained below 1% for most cases using the DECT method, which implies that the DECT method might be more suitable for measuring patient-specific tissue compositions to improve the accuracy of treatment planning for charged particle therapy. In this study, the effects of CT imaging artifacts due to the beam hardening effect, scatter, noise, patient movement, etc were not analyzed. The true potential of the DECT method achieved in theoretical conditions may not be fully achievable in clinical settings. Further research and development may be needed to take advantage of the DECT method to characterize individual human tissues.

  11. Stop smoking support programs

    Science.gov (United States)

    Smokeless tobacco - stop smoking programs; Stop smoking techniques; Smoking cessation programs; Smoking cessation techniques ... You can find out about smoking cessation programs from: Your ... Your employer Your local health department The National Cancer ...

  12. Sci-Thur AM: YIS – 04: Stopping power-to-Cherenkov power ratios and beam quality specification for clinical Cherenkov emission dosimetry of electrons: beam-specific effects and experimental validation

    International Nuclear Information System (INIS)

    Zlateva, Yana; Seuntjens, Jan; El Naqa, Issam

    2016-01-01

    Purpose: To advance towards clinical Cherenkov emission (CE)-based dosimetry by investigating beam-specific effects on Monte Carlo-calculated electron-beam stopping power-to-CE power ratios (SCRs), addressing electron beam quality specification in terms of CE, and validating simulations with measurements. Methods: The EGSnrc user code SPRRZnrc, used to calculate Spencer-Attix stopping-power ratios, was modified to instead calculate SCRs. SCRs were calculated for 6- to 22-MeV clinical electron beams from Varian TrueBeam, Clinac 21EX, and Clinac 2100C/D accelerators. Experiments were performed with a 20-MeV electron beam from a Varian TrueBeam accelerator, using a diffraction grating spectrometer with optical fiber input and a cooled back-illuminated CCD. A fluorophore was dissolved in the water to remove CE signal anisotropy. Results: It was found that angular spread of the incident beam has little effect on the SCR (≤ 0.3% at d max ), while both the electron spectrum and photon contamination increase the SCR at shallow depths and decrease it at large depths. A universal data fit of R 50 in terms of C 50 (50% CE depth) revealed a strong linear dependence (R 2 > 0.9999). The SCR was fit with a Burns-type equation (R 2 = 0.9974, NRMSD = 0.5%). Below-threshold incident radiation was found to have minimal effect on beam quality specification (< 0.1%). Experiments and simulations were in good agreement. Conclusions: Our findings confirm the feasibility of the proposed CE dosimetry method, contingent on computation of SCRs from additional accelerators and on further experimental validation. This work constitutes an important step towards clinical high-resolution out-of-beam CE dosimetry.

  13. Sci-Thur AM: YIS – 04: Stopping power-to-Cherenkov power ratios and beam quality specification for clinical Cherenkov emission dosimetry of electrons: beam-specific effects and experimental validation

    Energy Technology Data Exchange (ETDEWEB)

    Zlateva, Yana; Seuntjens, Jan; El Naqa, Issam [McGill University, Cedars Cancer Centre, University of Michigan (United States)

    2016-08-15

    Purpose: To advance towards clinical Cherenkov emission (CE)-based dosimetry by investigating beam-specific effects on Monte Carlo-calculated electron-beam stopping power-to-CE power ratios (SCRs), addressing electron beam quality specification in terms of CE, and validating simulations with measurements. Methods: The EGSnrc user code SPRRZnrc, used to calculate Spencer-Attix stopping-power ratios, was modified to instead calculate SCRs. SCRs were calculated for 6- to 22-MeV clinical electron beams from Varian TrueBeam, Clinac 21EX, and Clinac 2100C/D accelerators. Experiments were performed with a 20-MeV electron beam from a Varian TrueBeam accelerator, using a diffraction grating spectrometer with optical fiber input and a cooled back-illuminated CCD. A fluorophore was dissolved in the water to remove CE signal anisotropy. Results: It was found that angular spread of the incident beam has little effect on the SCR (≤ 0.3% at d{sub max}), while both the electron spectrum and photon contamination increase the SCR at shallow depths and decrease it at large depths. A universal data fit of R{sub 50} in terms of C{sub 50} (50% CE depth) revealed a strong linear dependence (R{sup 2} > 0.9999). The SCR was fit with a Burns-type equation (R{sup 2} = 0.9974, NRMSD = 0.5%). Below-threshold incident radiation was found to have minimal effect on beam quality specification (< 0.1%). Experiments and simulations were in good agreement. Conclusions: Our findings confirm the feasibility of the proposed CE dosimetry method, contingent on computation of SCRs from additional accelerators and on further experimental validation. This work constitutes an important step towards clinical high-resolution out-of-beam CE dosimetry.

  14. Material elemental decomposition in dual and multi-energy CT via a sparsity-dictionary approach for proton stopping power ratio calculation.

    Science.gov (United States)

    Shen, Chenyang; Li, Bin; Chen, Liyuan; Yang, Ming; Lou, Yifei; Jia, Xun

    2018-04-01

    Accurate calculation of proton stopping power ratio (SPR) relative to water is crucial to proton therapy treatment planning, since SPR affects prediction of beam range. Current standard practice derives SPR using a single CT scan. Recent studies showed that dual-energy CT (DECT) offers advantages to accurately determine SPR. One method to further improve accuracy is to incorporate prior knowledge on human tissue composition through a dictionary approach. In addition, it is also suggested that using CT images with multiple (more than two) energy channels, i.e., multi-energy CT (MECT), can further improve accuracy. In this paper, we proposed a sparse dictionary-based method to convert CT numbers of DECT or MECT to elemental composition (EC) and relative electron density (rED) for SPR computation. A dictionary was constructed to include materials generated based on human tissues of known compositions. For a voxel with CT numbers of different energy channels, its EC and rED are determined subject to a constraint that the resulting EC is a linear non-negative combination of only a few tissues in the dictionary. We formulated this as a non-convex optimization problem. A novel algorithm was designed to solve the problem. The proposed method has a unified structure to handle both DECT and MECT with different number of channels. We tested our method in both simulation and experimental studies. Average errors of SPR in experimental studies were 0.70% in DECT, 0.53% in MECT with three energy channels, and 0.45% in MECT with four channels. We also studied the impact of parameter values and established appropriate parameter values for our method. The proposed method can accurately calculate SPR using DECT and MECT. The results suggest that using more energy channels may improve the SPR estimation accuracy. © 2018 American Association of Physicists in Medicine.

  15. TU-FG-BRB-02: The Impact of Using Dual-Energy CT for Determining Proton Stopping Powers: Comparison Between Theory and Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Baer, E; Jee, K [Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts (United States); Zhang, R; Yang, K; Sharp, G; Liu, B [Massachusetts General Hospital, Boston, MA (United States); Lalonde, A [University of Montreal, Montreal, QC (Canada); Royle, G [University College London, London, London (United Kingdom); Bouchard, H [Universite de Montreal, Montreal, QC (Canada); Lu, H [Massachusetts General Hospital and Harvard Medical School, Boston, MA (United States)

    2016-06-15

    Purpose: To evaluate the clinical performance of dual-energy CT (DECT) in determining proton stopping power ratios (SPR) and demonstrate advantages over conventional single-energy CT (SECT). Methods: SECT and DECT scans of tissue-equivalent plastics as well as animal meat samples are performed with a Siemens SOMATOM Definition Flash. The methods of Schneider et al. (1996) and Bourque et al. (2014) are used to determine proton SPR on SECT and DECT images, respectively. Waterequivalent path length (WEPL) measurements of plastics and tissue samples are performed with a 195 MeV proton beam. WEPL values are determined experimentally using the depth-dose shift and dose extinction methods. Results: Comparison between CT-based and experimental WEPL is performed for 12 tissue-equivalent plastic as well as 6 meat boxes containing animal liver, kidney, heart, stomach, muscle and bones. For plastic materials, results show a systematic improvement in determining SPR with DECT, with a mean absolute error of 0.4% compared to 1.7% for SECT. For the meat samples, preliminary results show the ability for DECT to determine WEPL with a mean absolute value of 1.1% over all meat boxes. Conclusion: This work demonstrates the potential in using DECT for determining proton SPR with plastic materials in a clinical context. Further work is required to show the benefits of DECT for tissue samples. While experimental uncertainties could be a limiting factor to show the benefits of DECT over SECT for the meat samples, further work is required to adapt the DECT formalism in the context of clinical use, where noise and artifacts play an important role.

  16. TU-FG-BRB-02: The Impact of Using Dual-Energy CT for Determining Proton Stopping Powers: Comparison Between Theory and Experiments

    International Nuclear Information System (INIS)

    Baer, E; Jee, K; Zhang, R; Yang, K; Sharp, G; Liu, B; Lalonde, A; Royle, G; Bouchard, H; Lu, H

    2016-01-01

    Purpose: To evaluate the clinical performance of dual-energy CT (DECT) in determining proton stopping power ratios (SPR) and demonstrate advantages over conventional single-energy CT (SECT). Methods: SECT and DECT scans of tissue-equivalent plastics as well as animal meat samples are performed with a Siemens SOMATOM Definition Flash. The methods of Schneider et al. (1996) and Bourque et al. (2014) are used to determine proton SPR on SECT and DECT images, respectively. Waterequivalent path length (WEPL) measurements of plastics and tissue samples are performed with a 195 MeV proton beam. WEPL values are determined experimentally using the depth-dose shift and dose extinction methods. Results: Comparison between CT-based and experimental WEPL is performed for 12 tissue-equivalent plastic as well as 6 meat boxes containing animal liver, kidney, heart, stomach, muscle and bones. For plastic materials, results show a systematic improvement in determining SPR with DECT, with a mean absolute error of 0.4% compared to 1.7% for SECT. For the meat samples, preliminary results show the ability for DECT to determine WEPL with a mean absolute value of 1.1% over all meat boxes. Conclusion: This work demonstrates the potential in using DECT for determining proton SPR with plastic materials in a clinical context. Further work is required to show the benefits of DECT for tissue samples. While experimental uncertainties could be a limiting factor to show the benefits of DECT over SECT for the meat samples, further work is required to adapt the DECT formalism in the context of clinical use, where noise and artifacts play an important role.

  17. SU-E-T-161: Characterization and Validation of CT Simulator Hounsfield Units to Relative Stopping Power Values for Proton Treatment Planning

    International Nuclear Information System (INIS)

    Schnell, E; Ahmad, S; De La Fuente Herman, T

    2015-01-01

    Purpose: To develop a calibration curve that includes and minimizes the variations of Hounsfield Unit (HU) from a CT scanner to Relative Stopping Power (RSP) of tissues along the proton beam path. The variations are due to scanner and proton energy, technique, phantom size and placement, and tissue arrangement. Methods: A CIRS 062 M phantom with 10 plugs of known relative electron density (RED) was scanned through a 16 slice GE Discovery CT Simulator scanner. Three setup combinations of plug distributions and techniques clinically implemented for five treatment regions were scanned with energies of 100, 120, and 140 kV. Volumetric HU values were measured for each plug and scan. The RSP values derived through the Bethe-Bloch formula are currently being verified with parallel-plate ionization chamber measurements in water using 80, 150, and 225 MeV proton beam. Typical treatment plans for treatment regions of brain, head-&-neck, chest, abdomen, and pelvis are being planned and dose delivered will be compared with film and Optically Stimulated Luminescence (OSL) measurements. Results: Percentage variations were determined for each variable. For tissues close to water, variations were <1% from any given parameter. Tissues far from water equivalence (lung and bone) showed the greatest sensitivity to change (7.4% maximum) with scanner energy and up to 5.3% with positioning of the phantom. No major variations were observed for proton energies within the treatment range. Conclusion: When deriving a calibration curve, attention should be placed to low and high HU values. A thorough verification process of calculated vs. water-phantom measured RSP values at different proton energies, followed by dose validation of planned vs. measured doses in phantom with film and OSL detectors are currently being undertaken

  18. Mono and sequential ion irradiation induced damage formation and damage recovery in oxide glasses: Stopping power dependence of the mechanical properties

    International Nuclear Information System (INIS)

    Mir, A.H.; Monnet, I.; Toulemonde, M.; Bouffard, S.; Jegou, C.; Peuget, S.

    2016-01-01

    Simple and complex borosilicate glasses were irradiated with single and double ion beams of light and heavy ions over a broad fluence and stopping power range. As a result of the heavy ion irradiation (U, Kr, Au), the hardness was observed to diminish and saturate after a decrease by 35 ± 1%. Unlike slow and swift heavy ion irradiation, irradiation with light ions (He,O) induced a saturation hardness decrease of 18 ± 1% only. During double ion beam irradiation; where glasses were first irradiated with a heavy ion (gold) and then by a light ion (helium), the light ion irradiation induced partial damage recovery. As a consequence of the recovery effect, the hardness of the pre-irradiated glasses increased by 10–15% depending on the chemical composition. These results highlight that the nuclear energy loss and high electronic energy loss (≥4 keV/nm) result in significant and similar modifications whereas light ions with low electronic energy loss (≤1 keV/nm) result in only mild damage formation in virgin glasses and recovery in highly pre-damaged glasses. These results are important to understand the damage formation and recovery in actinide bearing minerals and in glasses subjected to self-irradiation by alpha decays. - Highlights: • Behavior of glasses strongly depends on the electronic energy loss (Se) of the ions. • High Se (≥4 keV/nm) induces large changes in comparison to lower Se values. • Apart from mild damage formation, low Se causes recovery of pre-existing damage. • Alpha induced partial recovery of the damage would occur in nuclear waste glasses.

  19. Experimental study on the influence of charge exchange on the stopping power in the interaction of chlorine with a gas and a deuterium plasma

    International Nuclear Information System (INIS)

    Nectoux, Marie

    1998-01-01

    This thesis is placed in the context of the physics of energy deposition of a multicharged heavy ion beam in matter at intermediate energies. The experiment gave measurements of energy loss as a function of final charge state for chlorine ions at 1.7 MeV/u in deuterium gas or plasma. In this way, we explore the influence of charge state evolution, depending on experimentally measured capture and ionization cross sections and the electron density of the target, on energy loss. The target is cylindrical and enclosed by two fast valves. The plasma is created in the gas by a discharge, which induces a magnetic perturbation of the beam (lens effect). This effect induces a divergent and misaligned outgoing beam. A simulation including charge state and velocity evolution of the projectile in flight in the magnetic field has been made in order to optimize beam analysis, to reach a precision better than 10 -3 in energy measurement. This study led to removal of the target to the 'Split Pole', a refocusing magnetic spectrometer. The first results obtained clearly show the dependence of energy loss on exit charge and especially on its evolution in the target. This is explained in terms of the lengths covered by the projectile in its successive charge states in the target, which depends on target electron density and the medium considered. In plasma, we observed an energy distribution with exit charge twice that observed in gas, because of a strong decrease of charge exchange. A comparison of data obtained in gas with stopping power calculated from Bethe-Bloch-Barkas theory leads to the necessity of including spatial extension of the projectile charge in the theory. (author)

  20. Optimum size of a calibration phantom for x-ray CT to convert the Hounsfield units to stopping power ratios in charged particle therapy treatment planning.

    Science.gov (United States)

    Inaniwa, T; Tashima, H; Kanematsu, N

    2018-03-01

    In charged-particle therapy treatment planning, the volumetric distribution of stopping power ratios (SPRs) of body tissues relative to water is used for patient dose calculation. The distribution is conventionally obtained from computed tomography (CT) images of a patient using predetermined conversion functions from the CT numbers to the SPRs. One of the biggest uncertainty sources of patient SPR estimation is insufficient correction of beam hardening arising from the mismatch between the size of the patient cross section and the calibration phantom for producing the conversion functions. The uncertainty would be minimized by selecting a suitable size for the cylindrical water calibration phantom, referred to as an 'effective size' of the patient cross section, Leffective. We investigated the Leffective for pelvis, abdomen, thorax, and head and neck regions by simulating an ideal CT system using volumetric models of the reference male and female phantoms. The Leffective values were 23.3, 20.3, 22.7 and 18.8 cm for the pelvis, abdomen, thorax, and head and neck regions, respectively, and the Leffective for whole body was 21.0 cm. Using the conversion function for a 21.0-cm-diameter cylindrical water phantom, we could reduce the root mean square deviation of the SPRs and their mean deviation to ≤0.011 and ≤0.001, respectively, in the whole body. Accordingly, for simplicity, the effective size of 21.0 cm can be used for the whole body, irrespective of body-part regions for treatment planning in clinical practice.

  1. Calculation of the protons stopping power in water using dielectric formalism in the MELF-GOS approach; Calculo do poder de freamento de protons em agua utilizando o formalismo dieletrico na aproximacao MELF-GOS

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Franciane; Mazer, Amanda Cristina; Hormaza, Joel Mesa [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Botucatu, SP (Brazil)

    2016-07-01

    In order to calculate the stopping power of protons, there are many very successful models at high energies, which are extrapolated to low-energy regions. From the point of view of application of proton beam in cancer treatment is just this low energy region the most relevant due to the dose deposition profile in depth for protons. In this work, we present a calculation of the stopping power of protons in a water target using the dielectric formalism in MELF-GOS approach. The results when compared to other models show good agreement for energies above 100 keV and lower values below this energy. This result should impact the range of values of protons and the Bragg peak position. (author)

  2. STOPOW/82 program for calculations of stopping powers and ranges for heavy ions in the energy range from 1 keV to 10 GeV/a.m.u

    International Nuclear Information System (INIS)

    Henniger, J.; Horlbeck, B.

    1983-01-01

    The program ST0POW/82 is created to calculate the stopping power and range of ions up to uranium in the energy range 1 keV/a. m. u. - 10 GeV/a. m. u. in any amorphous matter. The program is based on Ziegler's catalogue data and Ahlen's theoretical treatments. The Zsub(eff)sup(3) relativistic Bloch and Mott corrections and corrections on density effect are taken into account in the calculations. An opportunity of 9 different functions removal, derivative on the stopping power and range, for example, primary ionization and LET, and also of ion parameters, such as β, Zsub(eff)sup(2)/βsup(2) is foreseen. The program is written in FORTRAN language in version for the CDC-6500 computer. The program needs a minimized input also for compound targets. So it is useful for many problems in applied sciences and experimental physics

  3. CSDA range, stopping power and mean penetration depth energy relationships in some hydrocarbons and biologic materials for 10 eV to 100 MeV with the modified Rohrlich-Carlson model

    Energy Technology Data Exchange (ETDEWEB)

    Guemues, Hasan [Ondokuz Mayis University, Department of Physics, Faculty of Sciences and Arts, Samsun (Turkey); Bentabet, Abdelouahab [Bordj Bou Arreridj University, LCVRN, SNVSTU Faculty, El Anasser (Algeria)

    2017-05-15

    In this study, for some hydrocarbons and biological compounds, stopping power formula are presented, being valid for low and intermediate electron energies. In addition, calculation of the continuous slowing down approximation range (CSDA range) from the stopping power is also made. Calculation of the CSDA range for some hydrocarbons: C{sub 2}H{sub 6} (ethane), C{sub 4}H{sub 10} (butane), C{sub 6}H{sub 14} (hexane) C{sub 8}H{sub 18} (octane), C{sub 5}H{sub 5}N{sub 5} (adenine) and C{sub 5}H{sub 5}N{sub 5}O (guanine) have been introduced for incident electrons in the energy range 30 eV to 1 MeV. The range of electrons has been calculated within the continuous slowing down approximation (CSDA) using modified Rohrlich and Carlson formula of stopping power. Besides, we have calculated the mean penetration depths using a spherical geometric model developed by Bentabet (Vacuum 86:1855-1859, 35). The results have been compared with the other theoretical results, Monte Carlo code such as PENELOPE predictions and semi-empirical results. The calculated results of CSDA ranges for electrons in the energy range from 20 eV to 100 MeV are found to be in good agreement to within 10% with available date. (orig.)

  4. Determination of electronic stopping powers of 0.05–1 MeV/u {sup 131}Xe ions in C-, Ni- and Au-absorbers with calorimetric low temperature detectors

    Energy Technology Data Exchange (ETDEWEB)

    Echler, A., E-mail: artur.echler@iamp.physik.uni-giessen.de [GSI Helmholtz Center for Heavy Ion Research, Darmstadt (Germany); Institute for Atomic and Molecular Physics, University of Giessen (Germany); Institute for Physics, University of Mainz (Germany); Egelhof, P.; Grabitz, P. [GSI Helmholtz Center for Heavy Ion Research, Darmstadt (Germany); Institute for Physics, University of Mainz (Germany); Kettunen, H. [Department of Physics, University of Jyväskylä (Finland); Kraft-Bermuth, S. [Institute for Atomic and Molecular Physics, University of Giessen (Germany); Laitinen, M. [Department of Physics, University of Jyväskylä (Finland); Müller, K. [Institute for Atomic and Molecular Physics, University of Giessen (Germany); Rossi, M.; Trzaska, W.H.; Virtanen, A. [Department of Physics, University of Jyväskylä (Finland)

    2017-01-15

    A new experimental system for precise determination of electronic stopping powers of heavy ions has been set up at the accelerator laboratory of the University of Jyväskylä. The new setup, combining an established B-ToF system and an array of calorimetric low temperature detectors (CLTDs), has been used for the determination of electronic stopping powers of 0.05–1 MeV/u {sup 131}Xe ions in carbon, nickel and gold. Thereby advantage of the improved linearity and energy resolution of CLTDs as compared to the previously used ionization detector was taken to reduce energy calibration errors and to increase sensitivity for the energy loss determination, in particular at very low energies. The total uncertainties of 3–4% for C- and Ni-targets, and 5–7% for Au-targets, respectively, are dominated by the target properties, i.e. thickness determination and inhomogeneities. The results are compared to data from literature and to predictions of different theoretical computer codes. In the high energy part of the examined energy range the results are in good agreement with previously published data, while new stopping power data for very heavy ions in different Z{sub 2}-materials have been obtained at lower energies. Moreover, unexpectedly strong channeling effects for the transmission of the {sup 131}Xe ions in thin, partly polycrystalline nickel and gold target foils have been observed and investigated.

  5. TU-FG-BRB-04: A New Optimization Method for Pre-Treatment Patient-Specific Stopping-Power by Combining Proton Radiography and X-Ray CT

    International Nuclear Information System (INIS)

    Collins-Fekete, C; Schulte, R; Beaulieu, L; Seco, J

    2016-01-01

    Purpose: The relative stopping power (RSP) uncertainty is the largest contributor to the range uncertainty in proton therapy. The purpose of this work is to develop a robust and systematic method that yields accurate patient specific RSPs by combining pre-treatment X-ray CT and daily proton radiography. Methods: The method is formulated as a penalized least squares optimization (PLSO) problem min(|Ax-B|). The matrix A represents the cumulative path-length crossed in each material computed by calculating proton trajectories through the X-ray CT. The material RSPs are denoted by x and B is the pRad, expressed as water equivalent thickness. The equation is solved using a convex-conic optimizer. Geant4 simulations were made to assess the feasibility of the method. RSP extracted from the Geant4 materials were used as a reference and the clinical HU-RSP curve as a comparison. The PLSO was first tested on a Gammex RMI-467 phantom. Then, anthropomorphic phantoms of the head, pelvis and lung were studied and resulting RSPs were evaluated. A pencil beam was generated in each phantom to evaluate the proton range accuracy achievable by using the optimized RSPs. Finally, experimental data of a pediatric head phantom (CIRS) were acquired using a recently completed experimental pCT scanner. Results: Numerical simulations showed precise RSP (<0.75%) for Gammex materials except low-density lung (LN-300) (1.2%). Accurate RSP have been obtained for the head (µ=−0.10%, 1.5σ=1.12%), lung (µ=−0.33, 1.5σ=1.02%) and pelvis anthropomorphic phantoms (µ=0.12, 1.5σ=0,99%). The range precision has been improved with an average R80 difference to the reference (µ±1.5σ) of −0.20±0.35%, −0.47±0.92% and −0.06±0.17% in the head, lung and pelvis phantoms respectively, compared to the 3.5% clinical margin. Experimental HU-RSP curve have been produced on the CIRS pediatric head. Conclusion: The proposed PLSO with prior knowledge X-ray CT shows promising potential (R80 σ<1.0% over

  6. Agutaynen Glottal Stop.

    Science.gov (United States)

    Quakenbush, J. Stephen

    A study investigated the phonemic and morphophonemic patterning of the glottal stop in Agutaynen, a Meso-Philippine language, and some comparison with two northern Philippine languages. Agutaynen glottal stop has as its sole origin a neutralization of contrast rule, the operation of which can be noted in three different linguistic environments.…

  7. Dosimetric comparison of stopping power calibration with dual-energy CT and single-energy CT in proton therapy treatment planning

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Jiahua [Department of Physics, University of Adelaide, Adelaide, SA 5005 (Australia); Penfold, Scott N., E-mail: scott.penfold@adelaide.edu.au [Department of Physics, University of Adelaide, Adelaide, SA 5005, Australia and Department of Medical Physics, Royal Adelaide Hospital, Adelaide, SA 5000 (Australia)

    2016-06-15

    Purpose: The accuracy of proton dose calculation is dependent on the ability to correctly characterize patient tissues with medical imaging. The most common method is to correlate computed tomography (CT) numbers obtained via single-energy CT (SECT) with proton stopping power ratio (SPR). CT numbers, however, cannot discriminate between a change in mass density and change in chemical composition of patient tissues. This limitation can have consequences on SPR calibration accuracy. Dual-energy CT (DECT) is receiving increasing interest as an alternative imaging modality for proton therapy treatment planning due to its ability to discriminate between changes in patient density and chemical composition. In the current work we use a phantom of known composition to demonstrate the dosimetric advantages of proton therapy treatment planning with DECT over SECT. Methods: A phantom of known composition was scanned with a clinical SECT radiotherapy CT-simulator. The phantom was rescanned at a lower X-ray tube potential to generate a complimentary DECT image set. A set of reference materials similar in composition to the phantom was used to perform a stoichiometric calibration of SECT CT number to proton SPRs. The same set of reference materials was used to perform a DECT stoichiometric calibration based on effective atomic number. The known composition of the phantom was used to assess the accuracy of SPR calibration with SECT and DECT. Intensity modulated proton therapy (IMPT) treatment plans were generated with the SECT and DECT image sets to assess the dosimetric effect of the imaging modality. Isodose difference maps and root mean square (RMS) error calculations were used to assess dose calculation accuracy. Results: SPR calculation accuracy was found to be superior, on average, with DECT relative to SECT. Maximum errors of 12.8% and 2.2% were found for SECT and DECT, respectively. Qualitative examination of dose difference maps clearly showed the dosimetric advantages

  8. Luminescent beam stop

    Energy Technology Data Exchange (ETDEWEB)

    Bryant, Diane; Morton, Simon A.

    2017-10-25

    This disclosure provides systems, methods, and apparatus related to beam stops. In one aspect, a device comprises a luminescent material, a beam stop plate, and an optical fiber. The luminescent material is a parallelepiped having a first side and a second side that are squares and having a third side that is a rectangle or a square. The first side and the second side are perpendicular to the third side. The beam stop plate is attached to the first side of the luminescent material. The optical fiber has a first end and a second end, with the first end of the optical fiber attached to the third side of the luminescent material.

  9. "Stop Diabetes Now!"

    Science.gov (United States)

    ... of this page please turn Javascript on. Feature: Diabetes "Stop Diabetes Now!" Past Issues / Fall 2009 Table of Contents ... Tips for Seniors at Risk for Type 2 Diabetes Lifestyle changes that lead to weight loss—such ...

  10. Depression - stopping your medicines

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000570.htm Depression - stopping your medicines To use the sharing features ... prescription medicines you may take to help with depression, anxiety, or pain. Like any medicine, there are ...

  11. A new method to induce transitions in muonic atoms using a high-power tunable dye laser coupled to a stopping muon beam

    CERN Document Server

    Bertin, A; Duclos, J; Gastaldi, Ugo; Gorini, G; Neri, G; Picard, J; Pitzurra, O; Placci, A; Polacco, E; Stefanini, G; Torelli, G; Vitale, A; Zavattini, E

    1974-01-01

    An apparatus is described in which a ruby-pumped dye laser is used to induce transitions from the 2S to the 2P levels of the muonic ion ( mu He)/sup +/. The dye laser supplies infra-red radiation pulses in the wavelengths (8040-8180) AA, at typical repetition rates of 1 pulse every 4 s, with an energy release per pulse of 300 mJ for 1.2 J pumping energy. A special synchronization procedure is followed to trigger the laser in close coupling with the incoming muon beam which is stopped in a helium target at pressures between 40 and 50 atm. The other performances of the device are fully discussed with reference both to the laser facility and to the special high-pressure helium target. (23 refs).

  12. Stopping the unstoppable

    CERN Multimedia

    2002-01-01

    How do you stop two very high energy proton beams circulating in opposite directions around a 27-kilometre ring? The answer is the beam dumps. Two tunnels, pointing in opposite directions, are being constructed at point 6 of the LHC. These will allow the beams to be directed into two large beam dumps housed at the ends of the tunnels.

  13. Ready to stop

    DEFF Research Database (Denmark)

    Molitoris, Joseph; Dribe, Martin

    2016-01-01

    the Roteman Database for Stockholm, Sweden between 1878 and 1926 to examine the association of socioeconomic status and fertility and the adoption of stopping behaviour during the city's transition. Using piecewise constant hazard models and logistic regression, we find that a clear class pattern arises...

  14. High fluence effects on ion implantation stopping and range

    International Nuclear Information System (INIS)

    Selvi, S.; Tek, Z.; Oeztarhan, A.; Akbas, N.; Brown, I.G.

    2005-01-01

    We have developed a code STOPPO which can be used to modify the more-widely used ion implantation codes to more accurately predict the mean nuclear and electronic stopping power, preferential sputtering and range of heavy ions in monatomic target materials. In our simulations an effective atomic number and effective atomic mass are introduced into conveniently available analytical stopping cross-sections and a better fitting function for preferential sputtering yield is carefully evaluated for each ion implantation. The accuracy of the code confirmed experimentally by comparison with measured Rutherford backscattering spectrometry (RBS) concentration profiles for 130 keV Zr ions implanted into Be to fluences of 1 x 10 17 , 2 x 10 17 and 4 x 10 17 ions/cm 2 . We find a steady increase in the mean nuclear and electronic stopping powers of the target; the increase in nuclear stopping power is much greater than the increase in electronic stopping power

  15. Investigation of RADTRAN Stop Model input parameters for truck stops

    International Nuclear Information System (INIS)

    Griego, N.R.; Smith, J.D.; Neuhauser, K.S.

    1996-01-01

    RADTRAN is a computer code for estimating the risks and consequences as transport of radioactive materials (RAM). RADTRAN was developed and is maintained by Sandia National Laboratories for the US Department of Energy (DOE). For incident-free transportation, the dose to persons exposed while the shipment is stopped is frequently a major percentage of the overall dose. This dose is referred to as Stop Dose and is calculated by the Stop Model. Because stop dose is a significant portion of the overall dose associated with RAM transport, the values used as input for the Stop Model are important. Therefore, an investigation of typical values for RADTRAN Stop Parameters for truck stops was performed. The resulting data from these investigations were analyzed to provide mean values, standard deviations, and histograms. Hence, the mean values can be used when an analyst does not have a basis for selecting other input values for the Stop Model. In addition, the histograms and their characteristics can be used to guide statistical sampling techniques to measure sensitivity of the RADTRAN calculated Stop Dose to the uncertainties in the stop model input parameters. This paper discusses the details and presents the results of the investigation of stop model input parameters at truck stops

  16. Projectile-z3 and -z4 corrections to basic Bethe-Bloch stopping power theory and mean excitation energies of Al, Si, Ni, Ge, Se, Y, Ag and Au

    International Nuclear Information System (INIS)

    Porter, L.E.; Bryan, S.R.

    1980-01-01

    Three independent sets of measurements of the stopping power of solid elemental targets for alpha particles were previously analyzed in terms of basic Bethe-Bloch theory with the low velocity projectile-z 3 correction term included. These data for Al, Si, Ni, Ge, Se, Y, Ag and Au have now been analyzed with the Bloch projectile-z 4 term and a revised projectile-z 3 term incorporated in the Bethe-Bloch formula, the projectile-z 3 revision having been effected by variation of the single free parameter of the projectile-z 3 effect formalism. The value of this parameter, fixed at 1.8 in previous studies, which counteracts inclusion of the projectile-z 4 term is 1.3 +- 0.1 for all target elements except Si. (orig.)

  17. Optimally Stopped Optimization

    Science.gov (United States)

    Vinci, Walter; Lidar, Daniel

    We combine the fields of heuristic optimization and optimal stopping. We propose a strategy for benchmarking randomized optimization algorithms that minimizes the expected total cost for obtaining a good solution with an optimal number of calls to the solver. To do so, rather than letting the objective function alone define a cost to be minimized, we introduce a further cost-per-call of the algorithm. We show that this problem can be formulated using optimal stopping theory. The expected cost is a flexible figure of merit for benchmarking probabilistic solvers that can be computed when the optimal solution is not known, and that avoids the biases and arbitrariness that affect other measures. The optimal stopping formulation of benchmarking directly leads to a real-time, optimal-utilization strategy for probabilistic optimizers with practical impact. We apply our formulation to benchmark the performance of a D-Wave 2X quantum annealer and the HFS solver, a specialized classical heuristic algorithm designed for low tree-width graphs. On a set of frustrated-loop instances with planted solutions defined on up to N = 1098 variables, the D-Wave device is between one to two orders of magnitude faster than the HFS solver.

  18. How Can I Stop Cutting?

    Science.gov (United States)

    ... Educators Search English Español How Can I Stop Cutting? KidsHealth / For Teens / How Can I Stop Cutting? ... in a soft, cozy blanket Substitutes for the Cutting Sensation You'll notice that all the tips ...

  19. Inertial-confinement-fusion applications of ion-stopping theory

    International Nuclear Information System (INIS)

    More, R.M.; Lee, Y.T.; Bailey, D.S.

    1982-01-01

    Methods were developed to calculate: (1) the stopping power of a hot plasma target, (2) the charge-state of a fast ion projectile, and (3) the final disposition of the deposited energy. The first issue refers to the stopping power for protons. The proton stopping power is altered in high-density or high-temperature targets, especially at velocities below the stopping peak. The second issue concerns the application of a proton stopping curve to the arbitrary projectile. The third topic is more specialized to inertial fusion and concerns the partition of deposited energy between ion (nuclear motion) degrees of freedom and those corresponding to bound and free electrons. The question here is whether a thermal equilibrium plasma is produced

  20. Retroactive Stop Loss Special Pay

    Science.gov (United States)

    Pay (RSLSP), providing $500 for each month/partial month served in stop loss status. Service members served under stop loss must submit a claim for the special pay. Throughout the year, the services have or extension of service, became ineligible to receive retroactive stop loss special pay. There may be

  1. GMSB with light stops

    Energy Technology Data Exchange (ETDEWEB)

    Delgado, Antonio [Department of Physics, University of Notre Dame,225 Nieuwland Science Hall, IN 46556, Notre Dame (United States); Theory Division, Physics Department CERN,CH-1211 Geneva 23 (Switzerland); Garcia-Pepin, Mateo [Institut de Física d’Altes Energies, Universitat Autònoma de Barcelona,08193 Bellaterra, Barcelona (Spain); Quiros, Mariano [ICREA at Institut de Física d’Altes Energies, Universitat Autònoma de Barcelona,08193 Bellaterra, Barcelona (Spain)

    2015-08-31

    Gauge mediated supersymmetry breaking (GMSB) is an elegant mechanism to transmit supersymmetry breaking from the hidden to the MSSM observable sector, which solves the supersymmetric flavor problem. However, the smallness of the generated stop mixing requires superheavy stops to reproduce the experimental value of the Higgs mass. A possible way out is to extend the MSSM Higgs sector with singlets and/or triplets providing extra tree-level corrections to the Higgs mass. Singlets will not get any soft mass from GMSB and triplets will contribute to the ρ parameter which could be an issue. In this paper we explore the second possibility by introducing extra supersymmetric triplets with hypercharges Y=(0,±1), with a tree-level custodial SU(2){sub L}⊗SU(2){sub R} global symmetry in the Higgs sector protecting the ρ parameter: a supersymmetric generalization of the Georgi-Machacek model, dubbed as supersymmetric custodial triplet model (SCTM). The renormalization group running from the messenger to the electroweak scale mildly breaks the custodial symmetry. We will present realistic low-scale scenarios (with the NLSP being a Bino-like neutralino or the right-handed stau) based on general (non-minimal) gauge mediation and consistent with all present experimental data. Their main features are: i) Light (∼1 TeV) stops; ii) Exotic couplings (H{sup ±}W{sup ∓}Z and H{sup ±±}W{sup ∓}W{sup ∓}) absent in the MSSM and proportional to the triplets VEV, v{sub Δ}; and, iii) A possible (measurable) universality breaking of the Higgs couplings λ{sub WZ}=r{sub WW}/r{sub ZZ}≠1.

  2. Book Review: Stop, Write!

    Directory of Open Access Journals (Sweden)

    Hans Thulesius

    2013-06-01

    Full Text Available This book on writing grounded theory is intended for the empirical GT researcher who wants to pursue his/her research until publication. It is the first book devoted entirely to such a crucial issue as writing grounded theory. Thus, Stop, Write: Writing Grounded Theory, is a practical book that fills a gap in GT methodology. In the first chapter of the book, Dr. Glaser says, “Stop unending conceptualization, unending data coverage, and unending listening to others who would egg you on with additional data, ideas and/or requirements or simply wait too long”. The book teaches the reader how to actually write a grounded theory by “simply” writing up the sorted memos. This requires efficient sorting that is dealt with in chapter two on Sorting Memos, which includes precious repetition from Theoretical Sensitivity (1978. How writing can be done effectively is outlined in chapter three The Working Paper. Then follows chapter four on how to rework the first draft with the different tasks of editing for language and professionalism. Thereafter Dr. Glaser discusses Writing Problems in chapter five where he gives useful guidance on how to overcome writing blocks and problems with supervisors and dissertation committees. The book also deals with publishing and with collaboration as experienced between Barney Glaser and the cofounder of grounded theory, Anselm Strauss.

  3. GMSB with Light Stops

    CERN Document Server

    Delgado, Antonio; Quiros, Mariano

    2015-01-01

    Gauge mediated supersymmetry breaking (GMSB) is an elegant mechanism to transmit supersymmetry breaking from the hidden to the MSSM observable sector, which solves the supersymmetric flavor problem. However the smallness of the generated stop mixing requires superheavy stops to reproduce the experimental value of the Higgs mass. Two possible ways out are: i) To extend GMSB by direct superpotential messenger-MSSM Yukawa couplings to generate sizeable mixing, thus reintroducing the flavor problem; ii) To extend the MSSM Higgs sector with singlets and/or triplets providing extra tree-level corrections to the Higgs mass. Singlets will not get any soft mass from GMSB and triplets will contribute to the $\\rho$ parameter which could be an issue. In this paper we explore the second way by introducing extra supersymmetric triplets with hypercharges $Y=(0,\\pm 1)$, with a tree-level custodial $SU(2)_L\\otimes SU(2)_R$ global symmetry in the Higgs sector protecting the $\\rho$ parameter: a supersymmetric generalization of ...

  4. Court decisions: Preclusion clause prevents operating stop for Kruemmel nuclear power plant. [Administrative Court of Schleswig, decision 12D 79/83 of Oct. 5, 1983

    Energy Technology Data Exchange (ETDEWEB)

    1984-01-01

    According to section 7b of the Atomic Energy Act, once an incontestable permit has been given under section 7 of the Atomic Energy Act, third parties do not have a right of appeal in any subsequent licensing procedure if the said appeal is based on facts which have been put forward already, or could have been brought forward by any third party having had access to information or to the preliminary licence laid open for public inspection. If the licensing authority decided within the margin of discretion provided by the law, the administrative court may not replace this discretion by discretion of the court. If in accordance with section 1 of the Atomic Energy Act an examination of the issues involved may result in a possible decision confirming the licensing authority's view or also the court's view, the court is obliged to accept the decision taken by the licensing authority, due to the principle of separation of powers, unless the licensing authority decided on the basis of incorrect or irrelevant facts, or left out of consideration facts of major importance.

  5. You can't stop the music: reduced auditory alpha power and coupling between auditory and memory regions facilitate the illusory perception of music during noise.

    Science.gov (United States)

    Müller, Nadia; Keil, Julian; Obleser, Jonas; Schulz, Hannah; Grunwald, Thomas; Bernays, René-Ludwig; Huppertz, Hans-Jürgen; Weisz, Nathan

    2013-10-01

    Our brain has the capacity of providing an experience of hearing even in the absence of auditory stimulation. This can be seen as illusory conscious perception. While increasing evidence postulates that conscious perception requires specific brain states that systematically relate to specific patterns of oscillatory activity, the relationship between auditory illusions and oscillatory activity remains mostly unexplained. To investigate this we recorded brain activity with magnetoencephalography and collected intracranial data from epilepsy patients while participants listened to familiar as well as unknown music that was partly replaced by sections of pink noise. We hypothesized that participants have a stronger experience of hearing music throughout noise when the noise sections are embedded in familiar compared to unfamiliar music. This was supported by the behavioral results showing that participants rated the perception of music during noise as stronger when noise was presented in a familiar context. Time-frequency data show that the illusory perception of music is associated with a decrease in auditory alpha power pointing to increased auditory cortex excitability. Furthermore, the right auditory cortex is concurrently synchronized with the medial temporal lobe, putatively mediating memory aspects associated with the music illusion. We thus assume that neuronal activity in the highly excitable auditory cortex is shaped through extensive communication between the auditory cortex and the medial temporal lobe, thereby generating the illusion of hearing music during noise. Copyright © 2013 Elsevier Inc. All rights reserved.

  6. One-Stop Dispensing

    DEFF Research Database (Denmark)

    Houlind, Morten Baltzer; McNulty, Helle Bach Ølgaard; Treldal, Charlotte

    2018-01-01

    (1) Objective: To assess hospital medication costs and staff time between One-Stop Dispensing (OSD) and the Traditional Medication System (TMS), and to evaluate patient perspectives on OSD. (2) Methods: The study was conducted at Hvidovre Hospital, University of Copenhagen, Denmark in an elective...... gastric surgery and acute orthopedic surgery department. This study consists of three sub-studies including adult patients able to self-manage medication. In Sub-study 1, staff time used to dispense and administer medication in TMS was assessed. Medication cost and OSD staff time were collected in Sub......-study 2, while patient perspectives were assessed in Sub-study 3. Medication costs with two days of discharge medication were compared between measured OSD cost and simulated TMS cost for the same patients. Measured staff time in OSD was compared to simulated staff time in TMS for the same patients...

  7. Development of methodology for assessment of absorbed dose and stopping power for low energy conversion electrons; Desenvolvimento de uma metodologia para estimativa da dose absorvida e do poder de freamento para eletrons de conversao de baixa energia

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Ivan Pedro Salati de

    1995-08-01

    The evaluation of absorbed dose in the case of external and internalcontamination due to radionuclides is sometimes hard, because of the difficulties in the assessment of the absorbed dose caused by electrons with energy less than 100 KeV in mucous membrane. In this work, a methodology for assessment of absorbed dose and stopping power in VYNS (co-polymer of polivinyl chloride - acetate) absorbers, for the 62.5 KeV and 84-88 KeV energy {sup 109} Cd conversion electrons, working with a 4 {pi} proportional pressurized detector, is presented. In order to assure the reproducibility of measurement conditions, one of the detector halves has been used to obtain a spectrum of a thin {sup 109} Cd source, without absorber. The other half of the detector was used in concomitance to obtain spectra with different thicknesses if absorber. The absorbed energy was obtained subtracting each spectrum with absorber from the spectrum without absorber, which were stored in a microcomputer connected to signal processing systems by ACE type interface. The VYNS weight and thickness were evaluated using common radionuclide metrology procedures. As VYNS has characteristics similar to a tissue equivalent material, the results obtained are consistent with dosimetric concepts and have a good agreement with those of the literature. (author)

  8. Optimal design of a beam stop for Indus-2 using finite element heat

    Indian Academy of Sciences (India)

    The radiation source impinges ∼ 1 kW power on the beam stop and the heat transfer capabilities of the beam stop have been evaluated. Temperature distribution in the beam stop has been obtained under various cooling conditions using the finite element analysis calculations with ANSYS software. Design parameters of ...

  9. Has Human Evolution Stopped?

    Directory of Open Access Journals (Sweden)

    Alan R. Templeton

    2010-07-01

    Full Text Available It has been argued that human evolution has stopped because humans now adapt to their environment via cultural evolution and not biological evolution. However, all organisms adapt to their environment, and humans are no exception. Culture defines much of the human environment, so cultural evolution has actually led to adaptive evolution in humans. Examples are given to illustrate the rapid pace of adaptive evolution in response to cultural innovations. These adaptive responses have important implications for infectious diseases, Mendelian genetic diseases, and systemic diseases in current human populations. Moreover, evolution proceeds by mechanisms other than natural selection. The recent growth in human population size has greatly increased the reservoir of mutational variants in the human gene pool, thereby enhancing the potential for human evolution. The increase in human population size coupled with our increased capacity to move across the globe has induced a rapid and ongoing evolutionary shift in how genetic variation is distributed within and among local human populations. In particular, genetic differences between human populations are rapidly diminishing and individual heterozygosity is increasing, with beneficial health effects. Finally, even when cultural evolution eliminates selection on a trait, the trait can still evolve due to natural selection on other traits. Our traits are not isolated, independent units, but rather are integrated into a functional whole, so selection on one trait can cause evolution to occur on another trait, sometimes with mildly maladaptive consequences.

  10. UDI STOP Femminicidio

    Directory of Open Access Journals (Sweden)

    Giovanna Crivelli

    2014-04-01

    Full Text Available L'UDI, Unione Donne in Italia, ha collaborato con l'Osservatorio dei Processi Comunicativi a un numero monografico della rivista scientifica M@gm@ dal titolo "Violenza maschile e femminicidio". Il numero monografico vuole mettere a disposizione le analisi, l’esperienza e la storia nostra e delle nostre interlocutrici, come contributo al nostro comune lavoro di sensibilizzazione, contrasto alla violenza maschile sulle donne – femminicidio. “UDI STOP femminicidio” è da anni la nostra campagna contro la violenza di genere, la collaborazione con l’Osservatorio dei Processi Comunicativi è parte integrante di questo sforzo. Il primo e dichiarato dei nostri progetti politici è il contrasto alla cultura e al potere ideologico che consente il femminicidio, la subordinazione culturale e sociale, la percezione della donna come oggetto di dominio, la riduzione in schiavitù di tante donne, comprese molte donne prostitute... Sappiamo di non voler tradire una “responsabilità di genere” che deve necessariamente concretizzarsi in tanti “gesti responsabili”, nella lunga pazienza quotidiana che consente la sedimentazione di un cambiamento radicale nelle coscienze. Vogliamo continuare ad essere l’associazione che coniuga insieme la soggettività personale e l'assunzione diretta di responsabilità, della progettualità a lungo termine che non trova “contraddittorio” misurarsi con la solidarietà concreta e quotidiana con le altre donne, nel tentativo di far nascere le nuove maniere di pensare.

  11. Stopping the Bottle

    Science.gov (United States)

    ... difficult it can be to break the bottle habit. Longer bottle use may lead to cavities or ... Drinks for Kids Toddlers at the Table: Avoiding Power Struggles View more About Us Contact Us Partners ...

  12. Nitrogen Research Programme STOP

    International Nuclear Information System (INIS)

    Erisman, J.W.; Van der Eerden, L.

    2000-01-01

    Nitrogen pollution is one of the main threats to the environment now in the Netherlands as well as other parts of Europe. In order to address the main gaps on the issues of nitrogen pollution related to the local scale, the Ministries of Housing, Physical Planning and Environment (VROM) and of Agriculture, Nature Management and Fisheries (LNV) have initiated a research programme, the Dutch Nitrogen Research Programme (STOP), which aims to provide a scientific basis to develop and implement policy on a local scale for the realisation and conservation of the EHS ('Dutch Mainframe of Natural Landscapes'). The results of the programme show that the description of emissions from manure in the field is difficult to describe and show large uncertainties. On the contrary, emissions from housings could be modelled well, if local actual data were available. The OPS model to describe the dispersion and deposition was evaluated with the measurements and the limitations were quantified. It appears that the model works well on the long term, whereas on the short term (hours) and short distance (tenths of meters) there is large uncertainty, especially in complex terrain. Critical loads for nitrogen for ecosystems were evaluated. Furthermore, the effect of management options was quantified. A method to determine critical loads as a function of soil conditions, such as acidification and water availability was derived. This resulted in a combination of the soil model SMART and the so-called 'nature planner' (Natuurplanner). It was concluded that the combination of SMART, the nature planner and OPS provide a good tool to develop and support policy on the local scale. 4 refs

  13. On plasma coupling and turbulence effects in low velocity stopping

    Energy Technology Data Exchange (ETDEWEB)

    Kurilenkov, Yu K [Unified Institute for High Temperatures of Russian Academy of Sciences, 13/19 Izhorskaya Str., 125412 Moscow (Russian Federation); Maynard, G [Laboratoire de Physique des Gaz et des Plasmas, UMR-8578, Bat. 210, Universite Paris XI, F-91405 Orsay (France); Barriga-Carrasco, M D [Laboratoire de Physique des Gaz et des Plasmas, UMR-8578, Bat. 210, Universite Paris XI, F-91405 Orsay (France); Valuev, A A [Unified Institute for High Temperatures of Russian Academy of Sciences, 13/19 Izhorskaya Str., 125412 Moscow (Russian Federation)

    2006-04-28

    The problem of stopping power (SP) for projectile ions is analysed in terms of the dielectric function and effective collision frequency for moderately dense and strongly coupled plasmas (SCP). We consider several issues regarding the calculation of stopping power for correlated ensembles of particles and oscillators. In particular, effects of group (few particle) modes, transition from positive to negative dispersion and excitation of collective modes up to suprathermal level at plasma targets are addressed. Linear SP of dense suprathermal (nonlinear) plasma targets at different levels of target plasma turbulence is estimated. The force of suprathermal plasma oscillations on the projectile ions is mostly in the nature of increased frictional drag. The results obtained show the possibility of increasing low velocity stopping (up to 'turbulent' values) in comparison with losses in equilibrium dense plasma targets. Experimental conditions to create specific turbulent targets as well as some connection between stopping phenomena and SCP transport properties are discussed briefly.

  14. On plasma coupling and turbulence effects in low velocity stopping

    International Nuclear Information System (INIS)

    Kurilenkov, Yu K; Maynard, G; Barriga-Carrasco, M D; Valuev, A A

    2006-01-01

    The problem of stopping power (SP) for projectile ions is analysed in terms of the dielectric function and effective collision frequency for moderately dense and strongly coupled plasmas (SCP). We consider several issues regarding the calculation of stopping power for correlated ensembles of particles and oscillators. In particular, effects of group (few particle) modes, transition from positive to negative dispersion and excitation of collective modes up to suprathermal level at plasma targets are addressed. Linear SP of dense suprathermal (nonlinear) plasma targets at different levels of target plasma turbulence is estimated. The force of suprathermal plasma oscillations on the projectile ions is mostly in the nature of increased frictional drag. The results obtained show the possibility of increasing low velocity stopping (up to 'turbulent' values) in comparison with losses in equilibrium dense plasma targets. Experimental conditions to create specific turbulent targets as well as some connection between stopping phenomena and SCP transport properties are discussed briefly

  15. LHC Availability 2017: Technical Stop 1 to Technical Stop 2

    CERN Document Server

    Todd, Benjamin; Apollonio, Andrea; Walsh, David John; CERN. Geneva. ATS Department

    2017-01-01

    This document summarises the LHC machine availability for the period of Technical Stop 1 (TS1) to Technical Stop 2 (TS2) in 2017. This period was dedicated to proton physics with a bunch spacing of 25ns. This note has been produced and ratified by the Availability Working Group which has complied fault information for the period in question using the Accelerator Fault Tracker.

  16. Relativistic theory of stopping for heavy ions

    International Nuclear Information System (INIS)

    Lindhard, J.; So/rensen, A.H.

    1996-01-01

    We calculate the electronic stopping power and the corresponding straggling for ions of arbitrary charge number, penetrating matter at any relativistic energy. The stopping powers are calculated by a simple method. Its starting point is the deviation of the precise theory from first-order quantum perturbation. We show that this deviation can be expressed in terms of the transport cross section, σ tr , for scattering of a free electron by the ion. In the nonrelativistic case the deviation is precisely the Bloch correction to Bethe close-quote s formula; we look into the nonrelativistic case in order to clarify both some features of our method and a seeming paradox in Rutherford scattering. The corresponding relativistic correction is obtained from σ tr for scattering of a Dirac electron in the ion potential. Here, the major practical advantage of the method shows up; we need not find the scattering distribution, but merely a single quantity, σ tr , determined by differences of successive phase shifts. For a point nucleus our results improve and extend those of Ahlen. Our final results, however, are based on atomic nuclei with standard radii. Thereby, the stopping is changed substantially already for moderate values of γ=(1-v 2 /c 2 ) -1/2 . An asymptotic saturation in stopping is obtained. Because of finite nuclear size, recoil corrections remain negligible at all energies. The average square fluctuation in energy loss is calculated as a simple fluctuation cross section for a free electron. The fluctuation in the relativistic case is generally larger than that of the perturbation formula, by a factor of ∼2 endash 3 for heavy ions. But the finite nuclear radius leads to a strong reduction at high energies and the elimination of the factor γ 2 belonging to point nuclei. copyright 1996 The American Physical Society

  17. The gaseous emission of polymers under swift heavy ion irradiation: effect of the electronic stopping power; L'emission gazeuse des polymeres aliphatiques sous irradiation: effet du pouvoir d'arret electronique

    Energy Technology Data Exchange (ETDEWEB)

    Picq, V

    2000-07-01

    This thesis contributes to a better understanding of the damaging processes, which occur in polymers under swift heavy ion irradiation. The present study is exclusively devoted to the influence of the electronic stopping power, (dE/dx)e, on the molecular emission under irradiation. The irradiated polymers are polyethylene, polypropylene and poly-butene. The (dE/dx)e of the projectiles used varies from 3.5*10{sup -3} MeV.mg{sup -1}.cm{sup 2} (electron) to 39 MeV.mg{sup -1}.cm{sup 2} ({sup 58}Ni). We used two different experimental approaches in order to identify the nature of the emitted gases: mass spectrometry and infrared spectroscopy. The first technique is non selective, therefore, we could detect the emission of H{sub 2} and heavy molecules; it also gives information on the diffusion kinetics of the molecules formed. The use of infrared spectroscopy for this kind of analysis is new and the technique was developed at the laboratory. It enables us to identify, without any ambiguity, molecules with up to three carbon atoms. The experimental spectra are analysed by using reference spectra of pure gases, measured in our laboratory. We have quantified precisely each identified gas, and we have followed the evolution of the radiochemical yields with increasing (dE/dx)e. The results, obtained at different (dE/dx)e, inform us on the different mechanisms of gas molecules formation, for example the side group departure and, at high (dE/dx)e, the fragmentation of the main chain which is due to multiple ionisation of the macromolecule. (author)

  18. IMPACTS OF BUS STOP IMPROVEMENTS

    Science.gov (United States)

    2018-03-23

    Improving bus stops by providing shelters, seating, signage, and sidewalks is relatively inexpensive and popular among riders and local officials. Making such improvements, however, is not often a priority for U.S. transit providers because of compet...

  19. A whistle-stop tour of statistics

    National Research Council Canada - National Science Library

    Everitt, Brian

    2012-01-01

    "Preface according to my Penguin English dictionary, whistle-stop, used before a noun means 'consisting of brief stops in several places' and this whistle-stop tour of statistics does just that, with...

  20. Sweet Spots and Door Stops

    Science.gov (United States)

    Thompson, Michael; Tsui, Stella; Leung, Chi Fan

    2011-01-01

    A sweet spot is referred to in sport as the perfect place to strike a ball with a racquet or bat. It is the point of contact between bat and ball where maximum results can be produced with minimal effort from the hand of the player. Similar physics can be applied to the less inspiring examples of door stops; the perfect position of a door stop is…

  1. Probing Light Stops with Stoponium

    CERN Document Server

    Batell, Brian

    2015-01-01

    We derive new limits on light stops from diboson resonance searches in the $\\gamma\\gamma$, $Z \\gamma$, $ZZ$, $WW$ and $hh$ channels from the first run of the LHC. If the two-body decays of the light stop are mildly suppressed or kinematically forbidden, stoponium bound states will form in $pp$ collisions and subsequently decay via the pair annihilation of the constituent stops to diboson final states, yielding striking resonance signatures. Remarkably, we find that stoponium searches are highly complementary to direct collider searches and indirect probes of light stops such as Higgs coupling measurements. Using an empirical quarkonia potential model and including the first two $S$-wave stoponium states, we find that in the decoupling limit $m_{\\widetilde t_1} \\lesssim 130$ GeV is excluded for any value of the stop mixing angle and heavy stop mass by the combination of the latest resonance searches and the indirect constraints. The $\\gamma \\gamma$ searches are the most complementary to the indirect constraint...

  2. Second stop and sbottom searches with a stealth stop

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Hsin-Chia; Li, Lingfeng; Qin, Qin [Department of Physics, University of California,Davis, California 95616 (United States)

    2016-11-29

    The top squarks (stops) may be the most wanted particles after the Higgs boson discovery. The searches for the lightest stop have put strong constraints on its mass. However, there is still a search gap in the low mass region if the spectrum of the stop and the lightest neutralino is compressed. In that case, it may be easier to look for the second stop since naturalness requires both stops to be close to the weak scale. The current experimental searches for the second stop are based on the simplified model approach with the decay modes t̃{sub 2}→t̃{sub 1}Z and t̃{sub 2}→t̃{sub 1}h. However, in a realistic supersymmetric spectrum there is always a sbottom lighter than the second stop, hence the decay patterns are usually more complicated than the simplified model assumptions. In particular, there are often large branching ratios of the decays t̃{sub 2}→b̃{sub 1}W and b̃{sub 1}→t̃{sub 1}W as long as they are open. The decay chains can be even more complex if there are intermediate states of additional charginos and neutralinos in the decays. By studying several MSSM benchmark models at the 14 TeV LHC, we point out the importance of the multi-W final states in the second stop and the sbottom searches, such as the same-sign dilepton and multilepton signals, aside from the traditional search modes. The observed same-sign dilepton excesses at LHC Run 1 and Run 2 may be explained by some of our benchmark models. We also suggest that the vector boson tagging and a new kinematic variable may help to suppress the backgrounds and increase the signal significance for some search channels. Due to the complex decay patterns and lack of the dominant decay channels, the best reaches likely require a combination of various search channels at the LHC for the second stop and the lightest sbottom.

  3. Multi-arm group sequential designs with a simultaneous stopping rule.

    Science.gov (United States)

    Urach, S; Posch, M

    2016-12-30

    Multi-arm group sequential clinical trials are efficient designs to compare multiple treatments to a control. They allow one to test for treatment effects already in interim analyses and can have a lower average sample number than fixed sample designs. Their operating characteristics depend on the stopping rule: We consider simultaneous stopping, where the whole trial is stopped as soon as for any of the arms the null hypothesis of no treatment effect can be rejected, and separate stopping, where only recruitment to arms for which a significant treatment effect could be demonstrated is stopped, but the other arms are continued. For both stopping rules, the family-wise error rate can be controlled by the closed testing procedure applied to group sequential tests of intersection and elementary hypotheses. The group sequential boundaries for the separate stopping rule also control the family-wise error rate if the simultaneous stopping rule is applied. However, we show that for the simultaneous stopping rule, one can apply improved, less conservative stopping boundaries for local tests of elementary hypotheses. We derive corresponding improved Pocock and O'Brien type boundaries as well as optimized boundaries to maximize the power or average sample number and investigate the operating characteristics and small sample properties of the resulting designs. To control the power to reject at least one null hypothesis, the simultaneous stopping rule requires a lower average sample number than the separate stopping rule. This comes at the cost of a lower power to reject all null hypotheses. Some of this loss in power can be regained by applying the improved stopping boundaries for the simultaneous stopping rule. The procedures are illustrated with clinical trials in systemic sclerosis and narcolepsy. © 2016 The Authors. Statistics in Medicine Published by John Wiley & Sons Ltd. © 2016 The Authors. Statistics in Medicine Published by John Wiley & Sons Ltd.

  4. Higgs-Stoponium Mixing Near the Stop-Antistop Threshold

    CERN Document Server

    Bodwin, Geoffrey T; Wagner, Carlos E M

    2016-01-01

    Supersymmetric extensions of the standard model contain additional heavy neutral Higgs bosons that are coupled to heavy scalar top quarks (stops). This system exhibits interesting field theoretic phenomena when the Higgs mass is close to the stop-antistop production threshold. Existing work in the literature has examined the digluon-to-diphoton cross section near threshold and has focused on enhancements in the cross section that might arise either from the perturbative contributions to the Higgs-to-digluon and Higgs-to-diphoton form factors or from mixing of the Higgs boson with stoponium states. Near threshold, enhancements in the relevant amplitudes that go as inverse powers of the stop-antistop relative velocity require resummations of perturbation theory and/or nonperturbative treatments. We present a complete formulation of threshold effects at leading order in the stop-antistop relative velocity in terms of nonrelativistic effective field theory. We give detailed numerical calculations for the case in ...

  5. Stop. Write! Writing Grounded Theory

    Directory of Open Access Journals (Sweden)

    Barney G. Glaser, PhD, Hon. PhD

    2012-06-01

    Full Text Available The message in this book, the dictum in this book, is to stop and write when the Grounded Theory (GT methodology puts you in that ready position. Stop unending conceptualization, unending data coverage, and unending listening to others who would egg you on with additional data, ideas and/or requirements or simply wait too long. I will discuss these ideas in detail. My experience with PhD candidates is that for the few who write when ready, many do not and SHOULD. Simply put, many write-up, but many more should.

  6. Could stops lighten the top?

    International Nuclear Information System (INIS)

    Bilal, A.; Ellis, J.; Fogli, G.L.

    1990-01-01

    The analysis of the presently available electroweak data including radiative corrections in the standard model suggests that the top quark weighs more than the Z 0 . We examine whether squark loops in the minimal supersymmetric model, particularly those involving stops (partners of the top quark), could reduce substantially the preferred range of top quark masses. Given the present lower bounds on squark masses, we find that stop effects can reduce the central value of m t by at most a few GeV, although they do make a very heavy top quark increasingly unlikely. (orig.)

  7. Seismic stops vs. snubbers, a reliable alternative

    International Nuclear Information System (INIS)

    Cloud, R.L.; Anderson, P.H.; Leung, J.S.M.

    1988-01-01

    The Seismic Stops methodology has been developed to provide a reliable alternative for providing seismic support to nuclear power plant piping. The concept is based on using rigid passive supports with large clearances. These gaps permit unrestrained thermal expansion while limiting excessive seismic displacements. This type of restraint has performed successfully in fossil fueled power plants. A simplified production analysis tool has been developed which evaluates the nonlinear piping response including the effect of the gapped supports. The methodology utilizes the response spectrum approach and has been incorporated into a piping analysis computer program RLCA-GAP. Full scale shake table tests of piping specimens were performed to provide test correlation with the developed methodology. Analyses using RLCA-GAP were in good agreement with test results. A sample piping system was evaluated using the Seismic Stops methodology to replace the existing snubbers with passive gapped supports. To provide further correlation data, the sample system was also evaluated using nonlinear time history analysis. The correlation comparisons showed RLCA-GAP to be a viable methodology and a reliable alternative for snubber optimization and elimination. (orig.)

  8. Nuclear stopping in transmission experiments

    International Nuclear Information System (INIS)

    Glazov, Lev G.; Sigmund, Peter

    2003-01-01

    Energy-loss spectra, mean and peak energy loss, and straggling due to elastic nuclear scattering have been studied theoretically as a function of target thickness and deflection angle of an initially monochromatic and well-collimated ion beam. The goal of this work has been to provide a generally valid scheme for nuclear-stopping corrections, allowing to determine electronic-stopping forces from energy-loss spectra measured in transmission geometry. Calculations have been based on the generalized Bothe-Landau theory of energy loss and multiple scattering. Our peak energy losses at zero emergence angle show close (∼10%) agreement with predictions of Fastrup et al. on the basis of the Bohr-Williams theory. However, predicted mean and peak energy losses are found to more sensitively depend on the underlying interatomic potential than unrestricted, i.e. angle-integrated mean or peak energy losses. Both elastic energy loss and multiple scattering are known to obey scaling laws involving only two combinations of the pertinent variables and atomic parameters. The dependence on deflection angle and foil thickness of mean and peak energy loss obeys a simple combination of these scaling laws. Comments are made on potential errors due to uncertainties in the nuclear-stopping correction applied in the literature with specific reference to central papers in low-velocity stopping

  9. Stop searches in flavourful supersymmetry

    CERN Document Server

    Crivellin, Andreas; Tunstall, Lewis C.

    2016-01-01

    Natural realisations of supersymmetry require light stops ${\\tilde t}_1$, making them a prime target of LHC searches for physics beyond the Standard Model. Depending on the kinematic region, the main search channels are ${\\tilde t_1}\\to t \\tilde \\chi^0_1$, ${\\tilde t_1}\\to W b \\tilde \\chi^0_1$ and ${\\tilde t_1}\\to c \\tilde \\chi^0_1$. We first examine the interplay of these decay modes with ${\\tilde c_1}\\to c \\tilde \\chi^0_1$ in a model-independent fashion, revealing the existence of large regions in parameter space which are excluded for any ${\\tilde t_1}\\to c \\tilde \\chi^0_1$ branching ratio. This effect is then illustrated for scenarios with stop-scharm mixing in the right-handed sector, where it has previously been observed that the stop mass limits can be significantly weakened for large mixing. Our analysis shows that once the LHC bounds from ${\\tilde c_1}\\to c \\tilde \\chi^0_1$ searches are taken into account, non-zero stop-scharm mixing leads only to a modest increase in the allowed regions of parameter...

  10. Correlated ion stopping in plasmas

    International Nuclear Information System (INIS)

    Zwicknagel, G.; Deutsch, C.

    1997-01-01

    The basic features of correlated ion stopping in plasmas are demonstrated by employing two opposite extremes of cluster structures, a statistical model with a spatial ion distribution of Gaussian shape and the highly regular configuration of N-ion chains and cubic boxes. In the case of the ion chains the resonant character of correlated stopping due to the interference of the excited wake fields is discussed in detail. The general behavior of correlation effects is summarized and its dependence on the ratio of cluster size and interion spacing to the screening length in the plasma, as well as the ratio of the cluster velocity to the mean electron velocity in the target, is stressed out. The validity and applicability of the dielectric response formalism used for describing correlated stopping is critically reviewed. A scheme is presented to extend the linear formalism to weak nonlinear situations that occur, in particular, for small highly charged clusters at moderate or low velocities. For the Gaussian cluster a fit formula is given, which allows a fast and accurate calculation of the enhancement of stopping due to correlation effects and applies for all degrees of degeneracy of the electrons and arbitrary cluster velocities. copyright 1997 The American Physical Society

  11. Remote Shutoff Stops Runaway Lawnmower

    Science.gov (United States)

    Grambo, Alan A.

    2007-01-01

    In this article, the author describes how electronics students at Central Nine Career Center designed a kill switch circuit to stop a runaway lawnmower. This project is ideal for a career center since the electronics/robotics, small engines and horticulture classes can all work together on their respective parts of the modification, installation…

  12. Reparametrizations with given stop data

    DEFF Research Database (Denmark)

    Raussen, Martin

    2009-01-01

    In [1] we performed a systematic investigation of reparametrizations of continuous paths in a Hausdorff space that relies crucially on a proper understanding of stop data of a (weakly increasing) reprametrizations of the unit interval. I am grateful to Marco Grandis (Genova) for pointing out to me...

  13. Reparametrizations with given stop data

    DEFF Research Database (Denmark)

    Raussen, Martin

    In [1], we performed a systematic investigation of reparametrizations of continuous paths in a Hausdorff space that relies crucially on a proper understanding of stop data of a (weakly increasing) reparametrization of the unit interval. I am indebted to Marco Grandis (Genova) for pointing out tome...

  14. Plagiarism: Can It Be Stopped?

    Science.gov (United States)

    Christensen, G. Jay

    2011-01-01

    Plagiarism can be controlled, not stopped. The more appropriate question to ask is: What can be done to encourage students to "cheat" correctly by doing the assignment the way it was intended? Cheating by college students continues to reach epidemic proportions on selected campuses, as witnessed by the recent episode at Central Florida University,…

  15. Stop researching transformational leadership! Now!

    NARCIS (Netherlands)

    L.G. Tummers (Lars)

    2013-01-01

    markdownabstract__Intro__ Researchers all over the world, stop with your research on transformational leadership! Now! This could be the provocative conclusion after reading the recent article of Profs. Daan van Knippenberg and Sim Sitkin in The Academy of Management Annals (2013). These

  16. Stop researching transformational leadership! Now!

    OpenAIRE

    Tummers, Lars

    2013-01-01

    markdownabstract__Intro__ Researchers all over the world, stop with your research on transformational leadership! Now! This could be the provocative conclusion after reading the recent article of Profs. Daan van Knippenberg and Sim Sitkin in The Academy of Management Annals (2013). These leadership professors write about the problems surrounding transformational leadership.

  17. Persisting roughness when deposition stops.

    Science.gov (United States)

    Schwartz, Moshe; Edwards, S F

    2004-12-01

    Useful theories for growth of surfaces under random deposition of material have been developed by several authors. The simplest theory is that introduced by Edwards and Wilkinson (EW), which is linear and soluble. Its nonlinear generalization by Kardar, Parisi, and Zhang (KPZ) resulted in many subsequent studies. Yet both EW and KPZ theories contain an unphysical feature. When deposition of material is stopped, both theories predict that as time tends to infinity, the surface becomes flat. In fact, of course, the final surface is not flat, but simply has no gradients larger than the gradient related to the angle of repose. We modify the EW and KPZ theories to accommodate this feature and study the consequences for the simpler system which is a modification of the EW equation. In spite of the fact that the equation describing the evolution of the surface is not linear, we find that the steady state in the presence of noise is not very different in the long-wavelength limit from that of the linear EW equation. The situation is quite different from that of EW when deposition stops. Initially there is still some rearrangement of the surface, but that stops as everywhere on the surface the gradient is less than that related to the angle of repose. The most interesting feature observed after deposition stops is the emergence of history-dependent steady-state distributions.

  18. Tourette Syndrome: Help Stop Bullying

    Science.gov (United States)

    ... work on Tourette Syndrome Tourette Association information on bullying What it’s like to have Tourette – Mary tells her story What children wish people knew about Tourette Syndrome CDC Children’s Mental Health StopBullying.gov Features Media Sign up for Features ...

  19. Proposal for a CINDA-type stopping data bibliography (CISDA)

    International Nuclear Information System (INIS)

    Ivascu, M.; Bucurescu, D.; Avrigeanu, V.

    1980-11-01

    The present status and requirements of stopping power data (SD) are reviewed, by considering the significant trends in applications of nuclear data. The need of centralized information on SD is emphasized. If the establishing of compiled and evaluated SD libraries format is possible only through an internationally co-ordinated action, to produce a computerized index to bibliographic references on SD is an easier task. One describes a plan of a CINDA-type SD bibliography (named CISDA - Computer Index of Stopping Data) containing experimental, theoretical and evaluated works for stopping powers, range, energy and range straggling of ions with atomic mass and charge both larger than or equal to 1. The index organization and detailed field descriptions of reference records are presented. (author)

  20. Public inquiry related to the request by EDF of a definitive stopping and complete dismantling of the hardware storage installation of the Monts d'Arree nuclear power plant (INB n.162). Opinion and conclusions of the inquiry commission

    International Nuclear Information System (INIS)

    2010-03-01

    After a recall of the project of stopping and dismantling of the hardware storage installation (INB n.162) which had been created after the stopping and dismantling of the Monts d'Arree heavy water nuclear reactor (INB n.28), this report analyzes the results of the public inquiry, and highlights the arguments of those in favour of this project and those opposed to it. Then, it states the Inquiry Commission's opinion which addresses the request for a national public debate, the project justification, the inquiry file, the site radiological status, the site radiological control during works, the impacts of dismantling, the various risks (for the population and the workers, in terms of fire risks), the issue of radioactive wastes, economic aspects (costs, jobs, local economy, tourism and site image), and site reconversion

  1. Progress in understanding heavy-ion stopping

    Energy Technology Data Exchange (ETDEWEB)

    Sigmund, P., E-mail: sigmund@sdu.dk [Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, DK-5230 Odense M (Denmark); Schinner, A. [Institut für Experimentalphysik, Johannes Kepler Universität, A-4040 Linz (Austria)

    2016-09-01

    We report some highlights of our work with heavy-ion stopping in the energy range where Bethe stopping theory breaks down. Main tools are our binary stopping theory (PASS code), the reciprocity principle, and Paul’s data base. Comparisons are made between PASS and three alternative theoretical schemes (CasP, HISTOP and SLPA). In addition to equilibrium stopping we discuss frozen-charge stopping, deviations from linear velocity dependence below the Bragg peak, application of the reciprocity principle in low-velocity stopping, modeling of equilibrium charges, and the significance of the so-called effective charge.

  2. Progress in understanding heavy-ion stopping

    International Nuclear Information System (INIS)

    Sigmund, P.; Schinner, A.

    2016-01-01

    We report some highlights of our work with heavy-ion stopping in the energy range where Bethe stopping theory breaks down. Main tools are our binary stopping theory (PASS code), the reciprocity principle, and Paul’s data base. Comparisons are made between PASS and three alternative theoretical schemes (CasP, HISTOP and SLPA). In addition to equilibrium stopping we discuss frozen-charge stopping, deviations from linear velocity dependence below the Bragg peak, application of the reciprocity principle in low-velocity stopping, modeling of equilibrium charges, and the significance of the so-called effective charge.

  3. How to Stop Biting Your Nails

    Medline Plus

    Full Text Available ... your fingers and from your nails to your face and mouth. To help you stop biting your ... re inclined to bite may help solve the problem. Try to gradually stop biting your nails: Some ...

  4. How to Stop Biting Your Nails

    Medline Plus

    Full Text Available ... Mohs AUC MyDermPath+ Psoriasis Patient education resources ... Try to gradually stop biting your nails: Some doctors recommend taking a gradual approach to break the habit. Try to stop biting ...

  5. Summary the race to reinvent energy and stop global warming

    CERN Document Server

    2013-01-01

    Complete summary of Fred Krupp and Miriam Horn's book: ""Earth: The Sequel: The Race to Reinvent Energy and Stop Global Warming"". This summary of the ideas from Fred Krupp and Miriam Horn's book ""Earth: The Sequel"" explains how capitalism, as the most powerful economic force in the world, is the only engine of change that has the strength to stop global warming. In their book, the authors demonstrate how this can be achieved by installing a cap-and-trade initiative, providing genuine economic incentives for companies and reducing their carbon footprint. This summary explains their theory in

  6. Why does sleep stop migraine?

    Science.gov (United States)

    Bigal, Marcelo E; Hargreaves, Richard J

    2013-10-01

    The relationship between sleep and migraine headaches is complex. Changes in sleep patterns can trigger migraine attacks, and sleep disorders may be associated with increased migraine frequency. Furthermore, migraine patients and their doctors very consistently report that sleep relieves already established migraine attacks. Herein we will try to answer the question, "Why does sleep stop migraine?" Since evidence for this relationship is largely based on empirical clinical observation, we will not provide a clinical review of the association. Instead, we will focus on the pathophysiology of migraine attacks and its intersections with sleep biology.

  7. Optimal Stopping with Information Constraint

    International Nuclear Information System (INIS)

    Lempa, Jukka

    2012-01-01

    We study the optimal stopping problem proposed by Dupuis and Wang (Adv. Appl. Probab. 34:141–157, 2002). In this maximization problem of the expected present value of the exercise payoff, the underlying dynamics follow a linear diffusion. The decision maker is not allowed to stop at any time she chooses but rather on the jump times of an independent Poisson process. Dupuis and Wang (Adv. Appl. Probab. 34:141–157, 2002), solve this problem in the case where the underlying is a geometric Brownian motion and the payoff function is of American call option type. In the current study, we propose a mild set of conditions (covering the setup of Dupuis and Wang in Adv. Appl. Probab. 34:141–157, 2002) on both the underlying and the payoff and build and use a Markovian apparatus based on the Bellman principle of optimality to solve the problem under these conditions. We also discuss the interpretation of this model as optimal timing of an irreversible investment decision under an exogenous information constraint.

  8. Revised emission factors for gas engines including start/stop emissions

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, Malene; Boll Illerup, J.; Birr-Petersen, K.

    2008-06-15

    Liberalisation of the electricity market has led to Danish gas engine plants increasingly converting to the spot and regulating power markets. In order to offer regulating power, plants need to be able to start and stop the engines at the plants quickly. The liberalisation causes a considerable change of operation practice of the engines e.g. less full load operation hours /year. The project provides an inventory determining the scale of the emissions during the start and stop sequence as well as proposals for engine modifications aimed at reducing start/stop emissions. This report includes calculation of emission factors as well as an inventory of total emissions and reduction potentials. (au)

  9. Optimally stopped variational quantum algorithms

    Science.gov (United States)

    Vinci, Walter; Shabani, Alireza

    2018-04-01

    Quantum processors promise a paradigm shift in high-performance computing which needs to be assessed by accurate benchmarking measures. In this article, we introduce a benchmark for the variational quantum algorithm (VQA), recently proposed as a heuristic algorithm for small-scale quantum processors. In VQA, a classical optimization algorithm guides the processor's quantum dynamics to yield the best solution for a given problem. A complete assessment of the scalability and competitiveness of VQA should take into account both the quality and the time of dynamics optimization. The method of optimal stopping, employed here, provides such an assessment by explicitly including time as a cost factor. Here, we showcase this measure for benchmarking VQA as a solver for some quadratic unconstrained binary optimization. Moreover, we show that a better choice for the cost function of the classical routine can significantly improve the performance of the VQA algorithm and even improve its scaling properties.

  10. How to stop global warming

    International Nuclear Information System (INIS)

    Goldenberg, J.

    1990-01-01

    This paper reports on how to stop global warming. At the Toronto Conference on Climate Change in 1988, the world's industrialized nations agreed on a goal of cutting greenhouse gas emissions 20 percent by the year 2005. This would not stabilize atmospheric levels of greenhouse gases but would at least slow their accumulation. Although difficult to achieve, the Toronto goal is certainly reachable. Newer, more efficient technologies can lower energy consumption without effecting economic output. CFC- substitutes can provide refrigeration. In fact, an international carbon tax of just $1 per barrel of oil, or $6 per ton of coal, would generate more than enough revenue to pay for the necessary fuel-saving measures. This tax could result from an international agreement similar to the 1987 Montreal Protocol, which obliges its signatories to cut down on production of CFCs

  11. Stop Negative Thinking Effects for Drug Dependence

    OpenAIRE

    Windiarti, Sri Endang; Indriati, Indriati; Surachmi, Fajar

    2013-01-01

    The purpose of this study was to determine the effect of therapy stop thinking negatively against drug addiction in Rehabilitation Orphanage Rumah Damai Gunung Pati Semarang. This research is quasy experiment with pretest - posttes without the control group design. Thirty respondents were taken to the reseach sujects. Stop thinking negative therapy before and after thebehavior of drug addiction there are differences (t = 0.00), so it can be stated that the therapy stop thinking negatively inf...

  12. Are Stopped Strings Preferred in Sad Music?

    OpenAIRE

    David Huron; Caitlyn Trevor

    2017-01-01

    String instruments may be played either with open strings (where the string vibrates between the bridge and a hard wooden nut) or with stopped strings (where the string vibrates between the bridge and a performer's finger pressed against the fingerboard). Compared with open strings, stopped strings permit the use of vibrato and exhibit a darker timbre. Inspired by research on the timbre of sad speech, we test whether there is a tendency to use stopped strings in nominally sad music. Specifica...

  13. Slow, stopped and stored light

    International Nuclear Information System (INIS)

    Welch, G.; Scully, M.

    2005-01-01

    Light that can been slowed to walking pace could have applications in telecommunications, optical storage and quantum computing. Whether we use it to estimate how far away a thunderstorm is, or simply take it for granted that we can have a conversation with someone on the other side of the world, we all know that light travels extremely fast. Indeed, special relativity teaches us that nothing in the universe can ever move faster than the speed of light in a vacuum: 299 792 458 ms sup - sup 1. However, there is no such limitation on how slowly light can travel. For the last few years, researchers have been routinely slowing light to just a few metres per second, and have recently even stopped it dead in its tracks so that it can be stored for future use. Slow-light has considerable popular appeal, deriving perhaps from the importance of the speed of light in relativity and cosmology. If everyday objects such as cars or people can travel faster than 'slow' light, for example, then it might appear that relativistic effects could be observed at very low speeds. Although this is not the case, slow light nonetheless promises to play an important role in optical technology because it allows light to be delayed for any period of time desired. This could lead to all-optical routers that would increase the bandwidth of the Internet, and applications in optical data storage, quantum information and even radar. (U.K.)

  14. Stopping atoms with diode lasers

    International Nuclear Information System (INIS)

    Watts, R.N.; Wieman, C.E.

    1986-01-01

    The use of light pressure to cool and stop neutral atoms has been an area of considerable interest recently. Cooled neutral atoms are needed for a variety of interesting experiments involving neutral atom traps and ultrahigh-resolution spectroscopy. Laser cooling of sodium has previously been demonstrated using elegant but quite elaborate apparatus. These techniques employed stabilized dye lasers and a variety of additional sophisticated hardware. The authors have demonstrated that a frequency chirp technique can be implemented using inexpensive diode lasers and simple electronics. In this technique the atoms in an atomic beam scatter resonant photons from a counterpropagating laser beam. The momentum transfer from the photons slows the atoms. The primary difficulty is that as the atoms slow their Doppler shift changes, and so they are no longer in resonance with the incident photons. In the frequency chirp technique this is solved by rapidly changing the laser frequency so that the atoms remain in resonance. To achieve the necessary frequency sweep with a dye laser one must use an extremely sophisticated high-speed electrooptic modulator. With a diode laser, however, the frequency can be smoothly and rapidly varied over many gigahertz simply by changing the injection current

  15. Addressing production stops in the food industry

    DEFF Research Database (Denmark)

    Hansen, Zaza Nadja Lee; Herbert, Luke Thomas; Jacobsen, Peter

    2014-01-01

    This paper investigates the challenges in the food industry which causes the production lines to stop, illustrated by a case study of an SME size company in the baked goods sector in Denmark. The paper proposes key elements this sector needs to be aware of to effectively address production stops......, and gives examples of the unique challenges faced by the SME food industry....

  16. Perceptual assessment of fricative--stop coarticulation.

    Science.gov (United States)

    Repp, B H; Mann, V A

    1981-04-01

    The perceptual dependence of stop consonants on preceding fricatives [Mann and Repp, J. Acoust. Soc. Am. 69, 548--558 (1981)] was further investigated in two experiments employing both natural and synthetic speech. These experiments consistently replicated our original finding that listeners, report velar stops following [s]. In addition, our data confirmed earlier reports that natural fricative noises (excerpted from utterances of [st alpha], [sk alpha], [(formula: see text)k alpha]) contain cues to the following stop consonants; this was revealed in subjects' identifications of stops from isolated fricative noises and from stimuli consisting of these noises followed by synthetic CV portions drawn from a [t alpha]--[k alpha] continuum. However, these cues in the noise portion could not account for the contextual effect of fricative identity ([formula: see text] versus [sp) on stop perception (more "k" responses following [s]). Rather, this effect seems to be related to a coarticulatory influence of a preceding fricative on stop production; Subjects' responses to excised natural CV portions (with bursts and aspiration removed) were biased towards a relatively more forward place of stop articulation when the CVs had originally been preceded by [s]; and the identification of a preceding ambiguous fricative was biased in the direction of the original fricative context in which a given CV portion had been produced. These findings support an articulatory explanation for the effect of preceding fricatives on stop consonant perception.

  17. How to Stop Biting Your Nails

    Medline Plus

    Full Text Available ... of hangnails, or other triggers, such as boredom, stress, or anxiety. By figuring out what causes you to bite your nails, you can figure out how to avoid these situations and develop a plan to stop. Just knowing when you’re inclined to bite may help solve the problem. Try to gradually stop biting ...

  18. All in One Stop? The Accessibility of Work Support Programs at One-Stop Centers.

    Science.gov (United States)

    Richer, Elise; Kubo, Hitomi; Frank, Abbey

    The accessibility of work support programs at one-stop centers was examined in a study during which 33 telephone directors or managers of one-stop centers in 22 states were interviewed by telephone. The interviews established the existence of extensive differences between one-stop centers from the standpoint of all aspects of their operation,…

  19. Organic materials irradiated at very low temperature and at different stopping powers: examples of polyethylene and of cyclohexane molecules trapped in matrix; Materiaux organiques irradies a tres basse temperature et a differents pouvoirs d'arret: cas du polyethylene et des molecules de cyclohexane isolees en matrice

    Energy Technology Data Exchange (ETDEWEB)

    Melot, M

    2003-10-15

    This thesis concerns the formation mechanisms of defects created in organic materials during irradiation under vacuum, at very low temperature and at different electronic stopping powers. Analysis have been realised by infrared spectroscopy. The first part concerns polyethylene. Irradiating at 8 K allows to dissociate the direct irradiation effects (in cage reactions) and the radical recombination effects. According to the considered chemical groups, the radical mobility leads to very different changes for the formation radiochemical yields. The second part concerns the irradiation of cyclohexane molecules trapped in a solid argon matrix. We evaluate the contribution of intermolecular and intramolecular reactions. The intermolecular reactions have limited consequences when using low ionising radiations but are crucial for heavy ion irradiations. (author)

  20. Stopping of hypervelocity clusters in solids

    International Nuclear Information System (INIS)

    Anders, Christian; Ziegenhain, Gerolf; Urbassek, Herbert M; Bringa, Eduardo M

    2011-01-01

    Using molecular-dynamics simulations, we study the processes underlying the stopping of energetic clusters upon impact in matter. We investigate self-bombardment of both a metallic (Cu) and a van-der-Waals bonded (frozen Ar) target. Clusters with sizes up to N = 10 4 atoms and with energies per atom of E/N = 0.1-1600 eV atom -1 were studied. We find that the stopping force exerted on a cluster follows an N 2/3 -dependence with cluster size N; thus large clusters experience less stopping than equi-velocity atoms. In the course of being stopped, the cluster is strongly deformed and attains a roughly pancake shape. Due to the cluster inertia, maximum deformation occurs later than the maximum stopping force. The time scale of projectile stopping is set by t 0 , the time the cluster needs to cover its own diameter before impacting the target; it thus depends on both cluster size and velocity. The time when the cluster experiences its maximum stopping force is around (0.7-0.8)t 0 . We find that the cluster is deformed with huge strain rates of around 1/2t 0 ; this amounts to 10 11 -10 13 s -1 for the cases studied here. (paper)

  1. A light sneutrino rescues the light stop

    Energy Technology Data Exchange (ETDEWEB)

    Chala, M. [Departament de Física Tèorica, Universitat de València and IFIC, Universitat de València-CSIC,Dr. Moliner 50, E-46100 Burjassot (València) (Spain); Delgado, A. [Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556 (United States); Nardini, G. [Albert Einstein Center (AEC), Institute for Theoretical Physics (ITP), University of Bern,Sidlerstrasse 5, CH-3012 Bern (Switzerland); Quirós, M. [Institut de Física d’Altes Energies (IFAE), The Barcelona Institute of Science and Technology (BIST),Institució Catalana de Recerca i Estudis Avançats - ICREA, Campus UAB, 08193 Bellaterra, Barcelona (Spain)

    2017-04-18

    Stop searches in supersymmetric frameworks with R-parity conservation usually assume the lightest neutralino to be the lightest supersymmetric particle. In this paper we consider an alternative scenario in which the left-handed tau sneutrino is lighter than neutralinos and stable at collider scales, but possibly unstable at cosmological scales. Moreover the (mostly right-handed) stop t̃ is lighter than all electroweakinos, and heavier than the scalars of the third generation lepton doublet, whose charged component, τ̃, is heavier than the neutral one, ν̃. The remaining supersymmetric particles are decoupled from the stop phenomenology. In most of the parameter space, the relevant stop decays are only into tτ̃τ, tν̃ν and bν̃τ via off-shell electroweakinos. We constrain the branching ratios of these decays by recasting the most sensitive stop searches. Due to the “double invisible” kinematics of the t̃→tν̃ν process, and the low efficiency in tagging the tτ̃τ decay products, light stops are generically allowed. In the minimal supersymmetric standard model with ∼ 100 GeV sneutrinos, stops with masses as small as ∼ 350 GeV turn out to be allowed at 95% CL.

  2. Application of the RADTRAN 5 stop model

    International Nuclear Information System (INIS)

    Neuhauser, K.S.; Kanipe, R.L.; Weiner, R.F.

    1997-01-01

    A number of environmental impact analyses with the RADTRAN computer code have shown that dose to persons at stops is one of the largest components of incident-free dose during overland carriage of spent fuel and other radioactive materials (e.g., USDOE, 1994). The input data used in these analyses were taken from a 1983 study that reports actual observations of spent fuel shipments by truck. Early RADTRAN stop models, however, were insufficiently flexible to take advantage of the detailed information in the study. A more recent study of gasoline service stations that specialize in servicing large trucks, which are the most likely stop locations for shipments of Type B packages in the United States, has provided additional, detailed data on refueling/meal stops. The RADTRAN 5 computer code for transportation risk analysis allows exposures at stops to be more fully modeled than have previous releases of the code and is able to take advantage of detailed data. It is the intent of this paper first to compare results from RADTRAN and RADTRAN 5 for the old, low-resolution form of input data, and then to demonstrate what effect the new data and input format have on stop-dose estimates for an individual stop and for a hypothetical shipment route. Finally, these estimated public doses will be contrasted with doses calculated for a special population group -- inspectors

  3. Application of the radtran 5 stop model

    International Nuclear Information System (INIS)

    Neuhauser, K.S.; Kanipe, R.L.; Weiner, R.F.

    1998-01-01

    A number of environmental impact analyzes with the RADTRAN computer code have shown that dose to persons at stops is one of the largest components of incident-free dose during overland carriage of spent fuel and other radioactive materials. The input data used in these analyses were taken from a 1983 study that reports actual observations of spent fuel shipments by truck. Early RADTRAN stop models, however, were insufficiently flexible to take advantage of the detailed information in the study. A more recent study of gasoline service stations that specialize in servicing large trucks, which are the most likely stop locations for shipments of Type B packages in the United States, has provided additional, detailed data on refueling/meal stops. The RADTRAN 5 computer code for transportation risk analysis allows exposures at stops to be more fully modelled than have previous releases of the code and is able to take advantage of detailed data. It is the intent of this paper first to compare results from RADTRAN 4 and RADTRAN 5 for the old, low-resolution form of input data, and then to demonstrate what effect the new data and input format have on stop-dose estimates for an individual stop and for a hypothetical shipment route. Finally, these estimated public doses will be contrasted with doses calculated for a special population group-inspectors. (authors)

  4. Energy density, stopping and flow in ultrarelativistic heavy ion collisions

    International Nuclear Information System (INIS)

    Sorge, H.; von Keitz, A.; Mattiello, R.; Stoecker, H.; Greiner, W.

    1990-01-01

    The Lorentz invariant molecular dynamics approach (RQMD) is employed to investigate the space-time evolution of heavy ion collisions at energies (E kin = 10AGeV hor-ellipsis 200AGeV). The calculations for various nucleus nucleus reactions show a high degree of stopping power. The importance of secondary rescattering at these beam energies is demonstrated. The computed nucleon rapidity distributions are compared to available experimental data. It is demonstrated that nonlinear, collective effects like full stopping of target and projectile and matter flow could be expected for heavy projectiles only. For nuclear collisions in the Booster era at BNL and for the lead beam at CERN SPS the authors predict a stimulating future: then a nearly equilibrated, long lived (8 fm/c) macroscopic volume of very high energy density (> 1 GeV/fm 3 ) and baryon density (> 5 times ground state density) is produced

  5. Stop preaching to the converted

    Science.gov (United States)

    Landrum, Asheley R.; Lull, Robert B.

    2017-08-01

    Traditional moral arguments fail to persuade conservative climate sceptics. Pope Francis' gifting of his climate encyclical to President Trump prior to his leaving the Paris Agreement shows that even a religious leader's persuasive power is constrained by how his message resonates with conservative moral values.

  6. Analytical and Experimental Investigation on A Dynamic Thermo-Sensitive Electrical Parameter with Maximum dIC/dt during Turn-off for High Power Trench Gate/Field-Stop IGBT Modules

    DEFF Research Database (Denmark)

    Chen, Yuxiang; Luo, Haoze; Li, Wuhua

    2017-01-01

    collector current during turn-off process is developed in terms of the behavior characteristics of the inside storage carriers. Then, the inherent linear relationship between the maximum collector current falling rate dI{C}/dt and junction temperature T {j} is demonstrated and investigated. Fortunately......, benefitting from the presence of the intrinsic parasitic inductance L{rm eE} between the Kelvin and power emitters of IGBT modules, the maximum dI{C}/dt can be easily measured to validate the theoretical analysis. Consequently, the maximum dI{C}/dt during turn-off process is a promising DTSEP for IGBT module...

  7. Nuclear waste. Last stop Siberia?

    International Nuclear Information System (INIS)

    Popova, L.

    2006-01-01

    Safe and environmentally sound management of nuclear waste and spent fuel is an unresolved problem of nuclear power. But unlike other nuclear nations, Russia has much more problems with nuclear waste. Russia inherited these problems from the military programs and decades of nuclear fuel cycle development. Nuclear waste continue to mount, while the government does not pay serious enough attention to the solution of the waste problem and considers to increase the capacity of nuclear power plants (NPPs). There are more than 1000 nuclear waste storages in Russia.1 More than 70 million tons of the solid waste has been accumulated by the year 2005, including 14 million tons of tails of the decommissioned uranium mine in the North Caucasus. President Putin said that ''infrastructure of the waste processing is extremely insufficient''. (orig.)

  8. How to Stop Biting Your Nails

    Medline Plus

    Full Text Available ... figure out how to avoid these situations and develop a plan to stop. Just knowing when you’ ... a doctor. If you bite your nails and develop a skin or nail infection, consult a board- ...

  9. How to Stop Biting Your Nails

    Medline Plus

    Full Text Available ... your nails to your face and mouth. To help you stop biting your nails, dermatologists recommend the ... stress ball or silly putty instead. This will help keep your hands busy and away from your ...

  10. How to Stop Biting Your Nails

    Medline Plus

    Full Text Available ... and away from your mouth. Identify your triggers: These could be physical triggers, such as the presence ... nails, you can figure out how to avoid these situations and develop a plan to stop. Just ...

  11. How to Stop Biting Your Nails

    Medline Plus

    Full Text Available ... Skin dictionary Camp Discovery Good Skin Knowledge lesson plans and activities Video library Find a dermatologist Why ... how to avoid these situations and develop a plan to stop. Just knowing when you’re inclined ...

  12. Port Authority of Allegheny County Transit Stops

    Data.gov (United States)

    Allegheny County / City of Pittsburgh / Western PA Regional Data Center — All transit stops within the Port Authority of Allegheny County's service area for the November 20, 2016 - March (TBD) 2017 schedule period.

  13. Imagine stopping the progression of Alzheimer's

    Science.gov (United States)

    ... Issue Past Issues Imagine stopping the progression of Alzheimer's Past Issues / Fall 2006 Table of Contents For ... I have friends and loved ones suffering from Alzheimer's. But I can imagine… and hope for… a ...

  14. How to Stop Biting Your Nails

    Medline Plus

    Full Text Available ... Part 2: Origin Part 3: Function Textbook Study notes Image library 3-D animated image library Board ... gradually stop biting your nails: Some doctors recommend taking a gradual approach to break the habit. Try ...

  15. How to Stop Biting Your Nails

    Medline Plus

    Full Text Available ... Mohs AUC MyDermPath+ Psoriasis Patient education resources Practice Management Center Coding and reimbursement Coding MACRA Fee schedule ... your nails: Some doctors recommend taking a gradual approach to break the habit. Try to stop biting ...

  16. Power

    DEFF Research Database (Denmark)

    Elmholdt, Claus Westergård; Fogsgaard, Morten

    2016-01-01

    and creativity suggests that when managers give people the opportunity to gain power and explicate that there is reason to be more creative, people will show a boost in creative behaviour. Moreover, this process works best in unstable power hierarchies, which implies that power is treated as a negotiable....... It is thus a central point that power is not necessarily something that breaks down and represses. On the contrary, an explicit focus on the dynamics of power in relation to creativity can be productive for the organisation. Our main focus is to elaborate the implications of this for practice and theory...

  17. Inseparability of Go and Stop in Inhibitory Control: Go Stimulus Discriminability Affects Stopping Behavior.

    Science.gov (United States)

    Ma, Ning; Yu, Angela J

    2016-01-01

    Inhibitory control, the ability to stop or modify preplanned actions under changing task conditions, is an important component of cognitive functions. Two lines of models of inhibitory control have previously been proposed for human response in the classical stop-signal task, in which subjects must inhibit a default go response upon presentation of an infrequent stop signal: (1) the race model, which posits two independent go and stop processes that race to determine the behavioral outcome, go or stop; and (2) an optimal decision-making model, which posits that observers decides whether and when to go based on continually (Bayesian) updated information about both the go and stop stimuli. In this work, we probe the relationship between go and stop processing by explicitly manipulating the discrimination difficulty of the go stimulus. While the race model assumes the go and stop processes are independent, and therefore go stimulus discriminability should not affect the stop stimulus processing, we simulate the optimal model to show that it predicts harder go discrimination should result in longer go reaction time (RT), lower stop error rate, as well as faster stop-signal RT. We then present novel behavioral data that validate these model predictions. The results thus favor a fundamentally inseparable account of go and stop processing, in a manner consistent with the optimal model, and contradicting the independence assumption of the race model. More broadly, our findings contribute to the growing evidence that the computations underlying inhibitory control are systematically modulated by cognitive influences in a Bayes-optimal manner, thus opening new avenues for interpreting neural responses underlying inhibitory control.

  18. Inseparability of Go and Stop in Inhibitory Control: Go Stimulus Discriminability Affects Stopping Behavior

    Directory of Open Access Journals (Sweden)

    Ning eMa

    2016-03-01

    Full Text Available Inhibitory control, the ability to stop or modify preplanned actions under changing task conditions, is an important component of cognitive functions. Two lines of models of inhibitory control have previously been proposed for human response in the classical stop-signal task, in which subjects must inhibit a default go response upon presentation of an infrequent stop signal: (1 the race model, which posits two independent go and stop processes that race to determine the behavioral outcome, go or stop; and (2 an optimal decision-making model, which posits that observers decides whether and when to go based on continually (Bayesian updated information about both the go and stop stimuli. In this work, we probe the relationship between go and stop processing by explicitly manipulating the discrimination difficulty of the go stimulus. While the race model assumes the go and stop processes are independent, and therefore go stimulus discriminability should not affect the stop stimulus processing, we simulate the optimal model to show that it predicts harder go discrimination results in a longer go reaction time (RT, a lower stop error rate, as well as a faster stop-signal RT. We then present novel behavioral data that validate these model predictions. The results thus favor a fundamentally inseparable account of go and stop processing, in a manner consistent with the optimal model, and contradicting the independence assumption of the race model. More broadly, our findings contribute to the growing evidence that the computations underlying inhibitory control are systematically modulated by cognitive influences in a Bayes-optimal manner, thus opening new avenues for interpreting neural responses underlying inhibitory control.

  19. Conservation system during prolonged stops

    International Nuclear Information System (INIS)

    Fernandez, J.

    2015-01-01

    Although Sta. M. de Garona is currently in cease of operations, a preservation plan has been stablished in order to ensure that every system and component required at full power operation is maintained in adequate conditions, in case NUCLENOR decides a plant restart in near future. Based in different international references (EPRI, EDF, USA plants, combined cycles...), systems and equipment have been layup in the proper way and additional tests and inspections have been carried out to confirm their adequate condition. Plant configuration control has always been preserved and no impact in cease safety functions has taken place. Through this preservation plan, every SSC is maintained in the proper conditions to resume safe and reliable operation of the Plant. (Author)

  20. Clamped seismic metamaterials: ultra-low frequency stop bands

    International Nuclear Information System (INIS)

    Achaoui, Y; Enoch, S; Guenneau, S; Antonakakis, T; Brûlé, S; Craster, R V

    2017-01-01

    The regularity of earthquakes, their destructive power, and the nuisance of ground vibration in urban environments, all motivate designs of defence structures to lessen the impact of seismic and ground vibration waves on buildings. Low frequency waves, in the range 1–10 Hz for earthquakes and up to a few tens of Hz for vibrations generated by human activities, cause a large amount of damage, or inconvenience; depending on the geological conditions they can travel considerable distances and may match the resonant fundamental frequency of buildings. The ultimate aim of any seismic metamaterial, or any other seismic shield, is to protect over this entire range of frequencies; the long wavelengths involved, and low frequency, have meant this has been unachievable to date. Notably this is scalable and the effects also hold for smaller devices in ultrasonics. There are three approaches to obtaining shielding effects: bragg scattering, locally resonant sub-wavelength inclusions and zero-frequency stop-band media. The former two have been explored, but the latter has not and is examined here. Elastic flexural waves, applicable in the mechanical vibrations of thin elastic plates, can be designed to have a broad zero-frequency stop-band using a periodic array of very small clamped circles. Inspired by this experimental and theoretical observation, all be it in a situation far removed from seismic waves, we demonstrate that it is possible to achieve elastic surface (Rayleigh) wave reflectors at very large wavelengths in structured soils modelled as a fully elastic layer periodically clamped to bedrock. We identify zero frequency stop-bands that only exist in the limit of columns of concrete clamped at their base to the bedrock. In a realistic configuration of a sedimentary basin 15 m deep we observe a zero frequency stop-band covering a broad frequency range of 0–30 Hz. (paper)

  1. Human factors in design modifications: panel alternative stop in Almaraz

    International Nuclear Information System (INIS)

    Roman, Y.; Bote, J.

    2015-01-01

    Human Factors Engineering has acquired a crucial role in the development of any design modification (DM), where every aspect relative to any interaction with the human user has to be taken into account at any stage thereof. Considering this, during the last years, Almaraz Nuclear Powe Plants has developed a program of Human Factors Engineering in order to reach the internationally recognized standards or systematic collected on NUREG 0711 Human Factors Engineering Program Review Model (NRC). One of the most important projects of this program at Almaraz Nuclear Power Plant has been the implementation of the Alternative Stop Panel and their corresponding Transfer Panels. (Author)

  2. Bubble formation after a 20-m dive: deep-stop vs. shallow-stop decompression profiles

    NARCIS (Netherlands)

    Schellart, Nico A. M.; Corstius, Jan-Jaap Brandt; Germonpré, Peter; Sterk, Wouter

    2008-01-01

    OBJECTIVES: It is claimed that performing a "deep stop," a stop at about half of maximal diving depth (MDD), can reduce the amount of detectable precordial bubbles after the dive and may thus diminish the risk of decompression sickness. In order to ascertain whether this reduction is caused by the

  3. Measurements of Ion Stopping around the Bragg Peak in High-Energy-Density Plasmas

    Science.gov (United States)

    Frenje, Johan

    2015-11-01

    Over the last few decades, ion stopping in weakly- to strongly-coupled High-Energy-Density (HED) plasmas has been subject to extensive analytical and numerical studies, but only a limited set of experimental data exists to check the validity of these theories. Most of these experiments also did not probe the detailed characteristics of the Bragg peak (peak ion stopping) where the ion velocity is similar to the average thermal electron velocity. To the best of our knowledge, only one exploratory attempt to do this was conducted by Hicks et al., who were able to describe qualitatively the behavior of the Bragg peak for one plasma condition. The work described in this presentation makes significant advances over previous experimental efforts by quantitatively assessing the characteristics of the ion stopping, ranging from low-velocity stopping, through the Bragg peak, to high-velocity stopping for different HED plasma conditions. This was achieved by measuring the energy loss of DD-tritons, D3He-alphas, DD-protons and D3He-protons, with distinctly different velocities, and the results indicate that the stopping power varies strongly with Te and ne. This effort represents the first experimental test of state-of-art plasma-stopping-power theories around the Bragg peak, which is an important first step in our efforts of getting a fundamental understanding of DT-alpha stopping in HED plasmas, a prerequisite for understanding ignition margins in various implosion designs with varying hot spot areal density at the National Ignition Facility. The work described here was performed in part at the LLE National Laser User's Facility (NLUF), and was supported in part by US DOE (Grant No. DE-FG03- 03SF22691), LLNL (subcontract Grant No. B504974) and LLE (subcontract Grant No. 412160-001G).

  4. The extent of the stop coannihilation strip

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, John [King' s College London, Theoretical Particle Physics and Cosmology Group, Department of Physics, London (United Kingdom); CERN, Theory Division, Geneva 23 (Switzerland); Olive, Keith A. [University of Minnesota, School of Physics and Astronomy, Minneapolis, MN (United States); University of Minnesota, William I. Fine Theoretical Physics Institute, School of Physics and Astronomy, Minneapolis, MN (United States); Zheng, Jiaming [University of Minnesota, School of Physics and Astronomy, Minneapolis, MN (United States)

    2014-07-15

    Many supersymmetric models such as the constrained minimal supersymmetric extension of the Standard Model (CMSSM) feature a strip in parameter space where the lightest neutralino χ is identified as the lightest supersymmetric particle, the lighter stop squark t{sub 1} is the next-to-lightest supersymmetric particle (NLSP), and the relic χ cold darkmatter density is brought into the range allowed by astrophysics and cosmology by coannihilation with the lighter stop squark t{sub 1} NLSP. We calculate the stop coannihilation strip in the CMSSM, incorporating Sommerfeld enhancement effects, and we explore the relevant phenomenological constraints and phenomenological signatures. In particular, we show that the t{sub 1} may weigh several TeV, and its lifetime may be in the nanosecond range, features that are more general than the specific CMSSM scenarios that we study in this paper. (orig.)

  5. The stopping rules for winsorized tree

    Science.gov (United States)

    Ch'ng, Chee Keong; Mahat, Nor Idayu

    2017-11-01

    Winsorized tree is a modified tree-based classifier that is able to investigate and to handle all outliers in all nodes along the process of constructing the tree. It overcomes the tedious process of constructing a classical tree where the splitting of branches and pruning go concurrently so that the constructed tree would not grow bushy. This mechanism is controlled by the proposed algorithm. In winsorized tree, data are screened for identifying outlier. If outlier is detected, the value is neutralized using winsorize approach. Both outlier identification and value neutralization are executed recursively in every node until predetermined stopping criterion is met. The aim of this paper is to search for significant stopping criterion to stop the tree from further splitting before overfitting. The result obtained from the conducted experiment on pima indian dataset proved that the node could produce the final successor nodes (leaves) when it has achieved the range of 70% in information gain.

  6. Can Global Warming be Stopped?

    Science.gov (United States)

    Luria, M.

    2013-12-01

    Earlier this year, the CO2 levels exceeded the 400 ppm level and there is no sign that the 1-2 ppm annual increase is going to slow down. Concerns regarding the danger of global warming have been reported in numerous occasions for more than a generation, ever since CO2 levels reached the 350 ppm range in the mid 1980's. Nevertheless, all efforts to slow down the increase have showed little if any effect. Mobile sources, including surface and marine transportation and aviation, consist of 20% of the global CO2 emission. The only realistic way to reduce the mobile sources' CO2 signature is by improved fuel efficiency. However, any progress in this direction is more than compensated by continuous increased demand. Stationary sources, mostly electric power generation, are responsible for the bulk of the global CO2 emission. The measurements have shown, that the effect of an increase in renewable sources, like solar wind and geothermal, combined with conversion from coal to natural gas where possible, conservation and efficiency improvement, did not compensate the increased demand mostly in developing countries. Increased usage of nuclear energy can provide some relief in carbon emission but has the potential of even greater environmental hazard. A major decrease in carbon emission can be obtained by either significant reduction in the cost of non-carbon based energy sources or by of carbon sequestration. The most economical way to make a significant decrease in carbon emission is to apply carbon sequestration technology at large point sources that use coal. Worldwide there are about 10,000 major sources that burn >7 billion metric tons of coal which generate the equivalent of 30 trillion kwh. There is a limited experience in CO2 sequestration of such huge quantities of CO2, however, it is estimated that the cost would be US$ 0.01-0.1 per kwh. The cost of eliminating this quantity can be estimated at an average of 1.5 trillion dollars annually. The major emitters, US

  7. Evaluating the Effects of Traffic on Driver Stopping and Turn Signal Use at a Stop Sign: A Systematic Replication

    Science.gov (United States)

    Lebbon, Angela R.; Austin, John; Van Houten, Ron; Malenfant, Louis E.

    2007-01-01

    The current analyses of observational data found that oncoming traffic substantially affected driver stopping patterns and turn signal use at the target stop sign. The percentage of legal stops and turn signal use by drivers in the presence and absence of traffic was analyzed using a multi-element design. The results showed that legal stops were…

  8. Stopping dynamics of ions passing through correlated honeycomb clusters

    Science.gov (United States)

    Balzer, Karsten; Schlünzen, Niclas; Bonitz, Michael

    2016-12-01

    A combined nonequilibrium Green functions-Ehrenfest dynamics approach is developed that allows for a time-dependent study of the energy loss of a charged particle penetrating a strongly correlated system at zero and finite temperatures. Numerical results are presented for finite inhomogeneous two-dimensional Fermi-Hubbard models, where the many-electron dynamics in the target are treated fully quantum mechanically and the motion of the projectile is treated classically. The simulations are based on the solution of the two-time Dyson (Keldysh-Kadanoff-Baym) equations using the second-order Born, third-order, and T -matrix approximations of the self-energy. As application, we consider protons and helium nuclei with a kinetic energy between 1 and 500 keV/u passing through planar fragments of the two-dimensional honeycomb lattice and, in particular, examine the influence of electron-electron correlations on the energy exchange between projectile and electron system. We investigate the time dependence of the projectile's kinetic energy (stopping power), the electron density, the double occupancy, and the photoemission spectrum. Finally, we show that, for a suitable choice of the Hubbard model parameters, the results for the stopping power are in fair agreement with ab initio simulations for particle irradiation of single-layer graphene.

  9. Are Stopped Strings Preferred in Sad Music?

    Directory of Open Access Journals (Sweden)

    David Huron

    2017-01-01

    Full Text Available String instruments may be played either with open strings (where the string vibrates between the bridge and a hard wooden nut or with stopped strings (where the string vibrates between the bridge and a performer's finger pressed against the fingerboard. Compared with open strings, stopped strings permit the use of vibrato and exhibit a darker timbre. Inspired by research on the timbre of sad speech, we test whether there is a tendency to use stopped strings in nominally sad music. Specifically, we compare the proportion of potentially open-to-stopped strings in a sample of slow, minor-mode movements with matched major-mode movements. By way of illustration, a preliminary analysis of Samuel Barber's famous Adagio from his Opus 11 string quartet shows that the selected key (B-flat minor provides the optimum key for minimizing open string tones. However, examination of a broader controlled sample of quartet movements by Haydn, Mozart and Beethoven failed to exhibit the conjectured relationship. Instead, major-mode movements were found to avoid possible open strings more than slow minor-mode movements.

  10. How to Stop Biting Your Nails

    Medline Plus

    Full Text Available ... gloves to prevent biting. Replace the nail-biting habit with a good habit: When you feel like biting your nails, try ... recommend taking a gradual approach to break the habit. Try to stop biting one set of nails, ...

  11. Car Stopping Distance on a Tabletop

    Science.gov (United States)

    Haugland, Ole Anton

    2013-01-01

    Stopping distances in car braking can be an intriguing topic in physics teaching. It illustrates some basic principles of physics, and sheds valuable light on students' attitude towards aggressive driving. Due to safety considerations, it can be difficult to make experiments with actual car braking. (Contains 2 figures.)

  12. Bystanders Are the Key to Stopping Bullying

    Science.gov (United States)

    Padgett, Sharon; Notar, Charles E.

    2013-01-01

    Bullying is the dominance over another. Bullying occurs when there is an audience. Peer bystanders provide an audience 85% of instances of bullying. If you remove the audience bullying should stop. The article is a review of literature (2002-2013) on the role of bystanders; importance of bystanders; why bystanders behave as they do; resources to…

  13. Brownian Optimal Stopping and Random Walks

    International Nuclear Information System (INIS)

    Lamberton, D.

    2002-01-01

    One way to compute the value function of an optimal stopping problem along Brownian paths consists of approximating Brownian motion by a random walk. We derive error estimates for this type of approximation under various assumptions on the distribution of the approximating random walk

  14. Approximations for stop-loss reinsurance premiums

    NARCIS (Netherlands)

    Reijnen, Rajko; Albers, Willem/Wim; Kallenberg, W.C.M.

    2005-01-01

    Various approximations of stop-loss reinsurance premiums are described in literature. For a wide variety of claim size distributions and retention levels, such approximations are compared in this paper to each other, as well as to a quantitative criterion. For the aggregate claims two models are

  15. Stop-loss premiums under dependence

    NARCIS (Netherlands)

    Albers, Willem/Wim

    1999-01-01

    Stop-loss premiums are typically calculated under the assumption that the insured lives in the underlying portfolio are independent. Here we study the effects of small departures from this assumption. Using Edgeworth expansions, it is made transparent which configurations of dependence parameters

  16. Measurement of the Muon Stopping Power in Lead Tungstate

    CERN Document Server

    Chatrchyan, S; Sirunyan, A M; Adam, W; Arnold, B; Bergauer, H; Bergauer, T; Dragicevic, M; Eichberger, M; Erö, J; Friedl, M; Frühwirth, R; Ghete, V M; Hammer, J; Hänsel, S; Hoch, M; Hörmann, N; Hrubec, J; Jeitler, M; Kasieczka, G; Kastner, K; Krammer, M; Liko, D; Magrans de Abril, I; Mikulec, I; Mittermayr, F; Neuherz, B; Oberegger, M; Padrta, M; Pernicka, M; Rohringer, H; Schmid, S; Schöfbeck, R; Schreiner, T; Stark, R; Steininger, H; Strauss, J; Taurok, A; Teischinger, F; Themel, T; Uhl, D; Wagner, P; Waltenberger, W; Walzel, G; Widl, E; Wulz, C E; Chekhovsky, V; Dvornikov, O; Emeliantchik, I; Litomin, A; Makarenko, V; Marfin, I; Mossolov, V; Shumeiko, N; Solin, A; Stefanovitch, R; Suarez Gonzalez, J; Tikhonov, A; Fedorov, A; Karneyeu, A; Korzhik, M; Panov, V; Zuyeuski, R; Kuchinsky, P; Beaumont, W; Benucci, L; Cardaci, M; De Wolf, E A; Delmeire, E; Druzhkin, D; Hashemi, M; Janssen, X; Maes, T; Mucibello, L; Ochesanu, S; Rougny, R; Selvaggi, M; Van Haevermaet, H; Van Mechelen, P; Van Remortel, N; Adler, V; Beauceron, S; Blyweert, S; D'Hondt, J; De Weirdt, S; Devroede, O; Heyninck, J; Kalogeropoulos, A; Maes, J; Maes, M; Mozer, M U; Tavernier, S; Van Doninck, W; Van Mulders, P; Villella, I; Bouhali, O; Chabert, E C; Charaf, O; Clerbaux, B; De Lentdecker, G; Dero, V; Elgammal, S; Gay, A P R; Hammad, G H; Marage, P E; Rugovac, S; Vander Velde, C; Vanlaer, P; Wickens, J; Grunewald, M; Klein, B; Marinov, A; Ryckbosch, D; Thyssen, F; Tytgat, M; Vanelderen, L; Verwilligen, P; Basegmez, S; Bruno, G; Caudron, J; Delaere, C; Demin, P; Favart, D; Giammanco, A; Grégoire, G; Lemaitre, V; Militaru, O; Ovyn, S; Piotrzkowski, K; Quertenmont, L; Schul, N; Beliy, N; Daubie, E; Alves, G A; Pol, M E; Souza, M H G; Carvalho, W; De Jesus Damiao, D; De Oliveira Martins, C; Fonseca De Souza, S; Mundim, L; Oguri, V; Santoro, A; Silva Do Amaral, S M; Sznajder, A; Fernandez Perez Tomei, T R; Ferreira Dias, M A; Gregores, E M; Novaes, S F; Abadjiev, K; Anguelov, T; Damgov, J; Darmenov, N; Dimitrov, L; Genchev, V; Iaydjiev, P; Piperov, S; Stoykova, S; Sultanov, G; Trayanov, R; Vankov, I; Dimitrov, A; Dyulendarova, M; Kozhuharov, V; Litov, L; Marinova, E; Mateev, M; Pavlov, B; Petkov, P; Toteva, Z; Chen, G M; Chen, H S; Guan, W; Jiang, C H; Liang, D; Liu, B; Meng, X; Tao, J; Wang, J; Wang, Z; Xue, Z; Zhang, Z; Ban, Y; Cai, J; Ge, Y; Guo, S; Hu, Z; Mao, Y; Qian, S J; Teng, H; Zhu, B; Avila, C; Baquero Ruiz, M; Carrillo Montoya, C A; Gomez, A; Gomez Moreno, B; Ocampo Rios, A A; Osorio Oliveros, A F; Reyes Romero, D; Sanabria, J C; Godinovic, N; Lelas, K; Plestina, R; Polic, D; Puljak, I; Antunovic, Z; Dzelalija, M; Brigljevic, V; Duric, S; Kadija, K; Morovic, S; Fereos, R; Galanti, M; Mousa, J; Papadakis, A; Ptochos, F; Razis, P A; Tsiakkouri, D; Zinonos, Z; Hektor, A; Kadastik, M; Kannike, K; Müntel, M; Raidal, M; Rebane, L; Anttila, E; Czellar, S; Härkönen, J; Heikkinen, A; Karimäki, V; Kinnunen, R; Klem, J; Kortelainen, M J; Lampén, T; Lassila-Perini, K; Lehti, S; Lindén, T; Luukka, P; Mäenpää, T; Nysten, J; Tuominen, E; Tuominiemi, J; Ungaro, D; Wendland, L; Banzuzi, K; Korpela, A; Tuuva, T; Nedelec, P; Sillou, D; Besancon, M; Chipaux, R; Dejardin, M; Denegri, D; Descamps, J; Fabbro, B; Faure, J L; Ferri, F; Ganjour, S; Gentit, F X; Givernaud, A; Gras, P; Hamel de Monchenault, G; Jarry, P; Lemaire, M C; Locci, E; Malcles, J; Marionneau, M; Millischer, L; Rander, J; Rosowsky, A; Rousseau, D; Titov, M; Verrecchia, P; Baffioni, S; Bianchini, L; Bluj, M; Busson, P; Charlot, C; Dobrzynski, L; Granier de Cassagnac, R; Haguenauer, M; Miné, P; Paganini, P; Sirois, Y; Thiebaux, C; Zabi, A; Agram, J L; Besson, A; Bloch, D; Bodin, D; Brom, J M; Conte, E; Drouhin, F; Fontaine, J C; Gelé, D; Goerlach, U; Gross, L; Juillot, P; Le Bihan, A C; Patois, Y; Speck, J; Van Hove, P; Baty, C; Bedjidian, M; Blaha, J; Boudoul, G; Brun, H; Chanon, N; Chierici, R; Contardo, D; Depasse, P; Dupasquier, T; El Mamouni, H; Fassi, F; Fay, J; Gascon, S; Ille, B; Kurca, T; Le Grand, T; Lethuillier, M; Lumb, N; Mirabito, L; Perries, S; Vander Donckt, M; Verdier, P; Djaoshvili, N; Roinishvili, N; Roinishvili, V; Amaglobeli, N; Adolphi, R; Anagnostou, G; Brauer, R; Braunschweig, W; Edelhoff, M; Esser, H; Feld, L; Karpinski, W; Khomich, A; Klein, K; Mohr, N; Ostaptchouk, A; Pandoulas, D; Pierschel, G; Raupach, F; Schael, S; Schultz von Dratzig, A; Schwering, G; Sprenger, D; Thomas, M; Weber, M; Wittmer, B; Wlochal, M; Actis, O; Altenhöfer, G; Bender, W; Biallass, P; Erdmann, M; Fetchenhauer, G; Frangenheim, J; Hebbeker, T; Hilgers, G; Hinzmann, A; Hoepfner, K; Hof, C; Kirsch, M; Klimkovich, T; Kreuzer, P; Lanske, D; Merschmeyer, M; Meyer, A; Philipps, B; Pieta, H; Reithler, H; Schmitz, S A; Sonnenschein, L; Sowa, M; Steggemann, J; Szczesny, H; Teyssier, D; Zeidler, C; Bontenackels, M; Davids, M; Duda, M; Flügge, G; Geenen, H; Giffels, M; Haj Ahmad, W; Hermanns, T; Heydhausen, D; Kalinin, S; Kress, T; Linn, A; Nowack, A; Perchalla, L; Poettgens, M; Pooth, O; Sauerland, P; Stahl, A; Tornier, D; Zoeller, M H; Aldaya Martin, M; Behrens, U; Borras, K; Campbell, A; Castro, E; Dammann, D; Eckerlin, G; Flossdorf, A; Flucke, G; Geiser, A; Hatton, D; Hauk, J; Jung, H; Kasemann, M; Katkov, I; Kleinwort, C; Kluge, H; Knutsson, A; Kuznetsova, E; Lange, W; Lohmann, W; Mankel, R; Marienfeld, M; Meyer, A B; Miglioranzi, S; Mnich, J; Ohlerich, M; Olzem, J; Parenti, A; Rosemann, C; Schmidt, R; Schoerner-Sadenius, T; Volyanskyy, D; Wissing, C; Zeuner, W D; Autermann, C; Bechtel, F; Draeger, J; Eckstein, D; Gebbert, U; Kaschube, K; Kaussen, G; Klanner, R; Mura, B; Naumann-Emme, S; Nowak, F; Pein, U; Sander, C; Schleper, P; Schum, T; Stadie, H; Steinbrück, G; Thomsen, J; Wolf, R; Bauer, J; Blüm, P; Buege, V; Cakir, A; Chwalek, T; De Boer, W; Dierlamm, A; Dirkes, G; Feindt, M; Felzmann, U; Frey, M; Furgeri, A; Gruschke, J; Hackstein, C; Hartmann, F; Heier, S; Heinrich, M; Held, H; Hirschbuehl, D; Hoffmann, K H; Honc, S; Jung, C; Kuhr, T; Liamsuwan, T; Martschei, D; Mueller, S; Müller, Th; Neuland, M B; Niegel, M; Oberst, O; Oehler, A; Ott, J; Peiffer, T; Piparo, D; Quast, G; Rabbertz, K; Ratnikov, F; Ratnikova, N; Renz, M; Saout, C; Sartisohn, G; Scheurer, A; Schieferdecker, P; Schilling, F P; Schott, G; Simonis, H J; Stober, F M; Sturm, P; Troendle, D; Trunov, A; Wagner, W; Wagner-Kuhr, J; Zeise, M; Zhukov, V; Ziebarth, E B; Daskalakis, G; Geralis, T; Karafasoulis, K; Kyriakis, A; Loukas, D; Markou, A; Markou, C; Mavrommatis, C; Petrakou, E; Zachariadou, A; Gouskos, L; Katsas, P; Panagiotou, A; Evangelou, I; Kokkas, P; Manthos, N; Papadopoulos, I; Patras, V; Triantis, F A; Bencze, G; Boldizsar, L; Debreczeni, G; Hajdu, C; Hernath, S; Hidas, P; Horvath, D; Krajczar, K; Laszlo, A; Patay, G; Sikler, F; Toth, N; Vesztergombi, G; Beni, N; Christian, G; Imrek, J; Molnar, J; Novak, D; Palinkas, J; Szekely, G; Szillasi, Z; Tokesi, K; Veszpremi, V; Kapusi, A; Marian, G; Raics, P; Szabo, Z; Trocsanyi, Z L; Ujvari, B; Zilizi, G; Bansal, S; Bawa, H S; Beri, S B; Bhatnagar, V; Jindal, M; Kaur, M; 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Yang, Y; Zhang, L; Zhu, K; Zhu, R Y; Akgun, B; Carroll, R; Ferguson, T; Jang, D W; Jun, S Y; Paulini, M; Russ, J; Terentyev, N; Vogel, H; Vorobiev, I; Cumalat, J P; Dinardo, M E; Drell, B R; Ford, W T; Heyburn, B; Luiggi Lopez, E; Nauenberg, U; Stenson, K; Ulmer, K; Wagner, S R; Zang, S L; Agostino, L; Alexander, J; Blekman, F; Cassel, D; Chatterjee, A; Das, S; Gibbons, L K; Heltsley, B; Hopkins, W; Khukhunaishvili, A; Kreis, B; Kuznetsov, V; Patterson, J R; Puigh, D; Ryd, A; Shi, X; Stroiney, S; Sun, W; Teo, W D; Thom, J; Vaughan, J; Weng, Y; Wittich, P; Beetz, C P; Cirino, G; Sanzeni, C; Winn, D; Abdullin, S; Afaq, M A; Albrow, M; Ananthan, B; Apollinari, G; Atac, M; Badgett, W; Bagby, L; Bakken, J A; Baldin, B; Banerjee, S; Banicz, K; Bauerdick, L A T; Beretvas, A; Berryhill, J; Bhat, P C; Biery, K; Binkley, M; Bloch, I; Borcherding, F; Brett, A M; Burkett, K; Butler, J N; Chetluru, V; Cheung, H W K; Chlebana, F; Churin, I; Cihangir, S; Crawford, M; Dagenhart, W; Demarteau, M; Derylo, G; Dykstra, D; Eartly, D P; Elias, J E; Elvira, V D; Evans, D; Feng, L; Fischler, M; Fisk, I; Foulkes, S; Freeman, J; Gartung, P; Gottschalk, E; Grassi, T; Green, D; Guo, Y; Gutsche, O; Hahn, A; Hanlon, J; Harris, R M; Holzman, B; Howell, J; Hufnagel, D; James, E; Jensen, H; Johnson, M; Jones, C D; Joshi, U; Juska, E; Kaiser, J; Klima, B; Kossiakov, S; Kousouris, K; Kwan, S; Lei, C M; Limon, P; Lopez Perez, J A; Los, S; Lueking, L; Lukhanin, G; Lusin, S; Lykken, J; Maeshima, K; Marraffino, J M; Mason, D; McBride, P; Miao, T; Mishra, K; Moccia, S; Mommsen, R; Mrenna, S; Muhammad, A S; Newman-Holmes, C; Noeding, C; O'Dell, V; Prokofyev, O; Rivera, R; Rivetta, C H; Ronzhin, A; Rossman, P; Ryu, S; Sekhri, V; Sexton-Kennedy, E; Sfiligoi, I; Sharma, S; Shaw, T M; Shpakov, D; Skup, E; Smith, R P; Soha, A; Spalding, W J; Spiegel, L; Suzuki, I; Tan, P; Tanenbaum, W; Tkaczyk, S; Trentadue, R; Uplegger, L; Vaandering, E W; Vidal, R; Whitmore, J; Wicklund, E; Wu, W; Yarba, J; Yumiceva, F; Yun, J C; Acosta, D; Avery, P; Barashko, V; Bourilkov, D; Chen, M; Di Giovanni, G P; Dobur, D; Drozdetskiy, A; Field, R D; Fu, Y; Furic, I K; Gartner, J; Holmes, D; Kim, B; Klimenko, S; Konigsberg, J; Korytov, A; Kotov, K; Kropivnitskaya, A; Kypreos, T; Madorsky, A; Matchev, K; Mitselmakher, G; Pakhotin, Y; Piedra Gomez, J; Prescott, C; Rapsevicius, V; Remington, R; Schmitt, M; Scurlock, B; Wang, D; Yelton, J; Ceron, C; Gaultney, V; Kramer, L; Lebolo, L M; Linn, S; Markowitz, P; Martinez, G; Rodriguez, J L; Adams, T; Askew, A; Baer, H; Bertoldi, M; Chen, J; Dharmaratna, W G D; Gleyzer, S V; Haas, J; Hagopian, S; Hagopian, V; Jenkins, M; Johnson, K F; Prettner, E; Prosper, H; Sekmen, S; Baarmand, M M; Guragain, S; Hohlmann, M; Kalakhety, H; Mermerkaya, H; Ralich, R; Vodopiyanov, I; Abelev, B; Adams, M R; Anghel, I M; Apanasevich, L; Bazterra, V E; Betts, R R; Callner, J; Castro, M A; Cavanaugh, R; Dragoiu, C; Garcia-Solis, E J; Gerber, C E; Hofman, D J; Khalatian, S; Mironov, C; Shabalina, E; Smoron, A; Varelas, N; Akgun, U; Albayrak, E A; Ayan, A S; Bilki, B; Briggs, R; Cankocak, K; Chung, K; Clarida, W; Debbins, P; Duru, F; Ingram, F D; Lae, C K; McCliment, E; Merlo, J P; Mestvirishvili, A; Miller, M J; Moeller, A; Nachtman, J; Newsom, C R; Norbeck, E; Olson, J; Onel, Y; Ozok, F; Parsons, J; Schmidt, I; Sen, S; Wetzel, J; Yetkin, T; Yi, K; Barnett, B A; Blumenfeld, B; Bonato, A; Chien, C Y; Fehling, D; Giurgiu, G; Gritsan, A V; Guo, Z J; Maksimovic, P; Rappoccio, S; Swartz, M; Tran, N V; Zhang, Y; Baringer, P; Bean, A; Grachov, O; Murray, M; Radicci, V; Sanders, S; Wood, J S; Zhukova, V; Bandurin, D; Bolton, T; Kaadze, K; Liu, A; Maravin, Y; Onoprienko, D; Svintradze, I; Wan, Z; Gronberg, J; Hollar, J; Lange, D; Wright, D; Baden, D; Bard, R; Boutemeur, M; Eno, S C; Ferencek, D; Hadley, N J; Kellogg, R G; Kirn, M; Kunori, S; Rossato, K; Rumerio, P; Santanastasio, F; Skuja, A; Temple, J; Tonjes, M B; Tonwar, S C; Toole, T; Twedt, E; Alver, B; Bauer, G; Bendavid, J; Busza, W; Butz, E; Cali, I A; Chan, M; D'Enterria, D; Everaerts, P; Gomez Ceballos, G; Hahn, K A; Harris, P; Jaditz, S; Kim, Y; Klute, M; Lee, Y J; Li, W; Loizides, C; Ma, T; Miller, M; Nahn, S; Paus, C; Roland, C; Roland, G; Rudolph, M; Stephans, G; Sumorok, K; Sung, K; Vaurynovich, S; Wenger, E A; Wyslouch, B; Xie, S; Yilmaz, Y; Yoon, A S; Bailleux, D; Cooper, S I; Cushman, P; Dahmes, B; De Benedetti, A; Dolgopolov, A; Dudero, P R; Egeland, R; Franzoni, G; Haupt, J; Inyakin, A; Klapoetke, K; Kubota, Y; Mans, J; Mirman, N; Petyt, D; Rekovic, V; Rusack, R; Schroeder, M; Singovsky, A; Zhang, J; Cremaldi, L M; Godang, R; Kroeger, R; Perera, L; Rahmat, R; Sanders, D A; Sonnek, P; Summers, D; Bloom, K; Bockelman, B; Bose, S; Butt, J; Claes, D R; Dominguez, A; Eads, M; Keller, J; Kelly, T; Kravchenko, I; Lazo-Flores, J; Lundstedt, C; Malbouisson, H; Malik, S; Snow, G R; Baur, U; Iashvili, I; Kharchilava, A; Kumar, A; Smith, K; Strang, M; Alverson, G; Barberis, E; Boeriu, O; Eulisse, G; Govi, G; McCauley, T; Musienko, Y; Muzaffar, S; Osborne, I; Paul, T; Reucroft, S; Swain, J; Taylor, L; Tuura, L; Anastassov, A; Gobbi, B; Kubik, A; Ofierzynski, R A; Pozdnyakov, A; Schmitt, M; Stoynev, S; Velasco, M; Won, S; Antonelli, L; Berry, D; Hildreth, M; Jessop, C; Karmgard, D J; Kolberg, T; Lannon, K; Lynch, S; Marinelli, N; Morse, D M; Ruchti, R; Slaunwhite, J; Warchol, J; Wayne, M; Bylsma, B; Durkin, L S; Gilmore, J; Gu, J; Killewald, P; Ling, T Y; Williams, G; Adam, N; Berry, E; Elmer, P; Garmash, A; Gerbaudo, D; Halyo, V; Hunt, A; Jones, J; Laird, E; Marlow, D; Medvedeva, T; Mooney, M; Olsen, J; Piroué, P; Stickland, D; Tully, C; Werner, J S; Wildish, T; Xie, Z; Zuranski, A; Acosta, J G; Bonnett Del Alamo, M; Huang, X T; Lopez, A; Mendez, H; Oliveros, S; Ramirez Vargas, J E; Santacruz, N; Zatzerklyany, A; Alagoz, E; Antillon, E; Barnes, V E; Bolla, G; Bortoletto, D; Everett, A; Garfinkel, A F; Gecse, Z; Gutay, L; Ippolito, N; Jones, M; Koybasi, O; Laasanen, A T; Leonardo, N; Liu, C; Maroussov, V; Merkel, P; Miller, D H; Neumeister, N; Sedov, A; Shipsey, I; Yoo, H D; Zheng, Y; Jindal, P; Parashar, N; Cuplov, V; Ecklund, K M; Geurts, F J M; Liu, J H; Maronde, D; Matveev, M; Padley, B P; Redjimi, R; Roberts, J; Sabbatini, L; Tumanov, A; Betchart, B; Bodek, A; Budd, H; Chung, Y S; de Barbaro, P; Demina, R; Flacher, H; Gotra, Y; Harel, A; Korjenevski, S; Miner, D C; Orbaker, D; Petrillo, G; Vishnevskiy, D; Zielinski, M; Bhatti, A; Demortier, L; Goulianos, K; Hatakeyama, K; Lungu, G; Mesropian, C; Yan, M; Atramentov, O; Bartz, E; Gershtein, Y; Halkiadakis, E; Hits, D; Lath, A; Rose, K; Schnetzer, S; Somalwar, S; Stone, R; Thomas, S; Watts, T L; Cerizza, G; Hollingsworth, M; Spanier, S; Yang, Z C; York, A; Asaadi, J; Aurisano, A; Eusebi, R; Golyash, A; Gurrola, A; Kamon, T; Nguyen, C N; Pivarski, J; Safonov, A; Sengupta, S; Toback, D; Weinberger, M; Akchurin, N; Berntzon, L; Gumus, K; Jeong, C; Kim, H; Lee, S W; Popescu, S; Roh, Y; Sill, A; Volobouev, I; Washington, E; Wigmans, R; Yazgan, E; Engh, D; Florez, C; Johns, W; Pathak, S; Sheldon, P; Andelin, D; Arenton, M W; Balazs, M; Boutle, S; Buehler, M; Conetti, S; Cox, B; Hirosky, R; Ledovskoy, A; Neu, C; Phillips II, D; Ronquest, M; Yohay, R; Gollapinni, S; Gunthoti, K; Harr, R; Karchin, P E; Mattson, M; Sakharov, A; Anderson, M; Bachtis, M; Bellinger, J N; Carlsmith, D; Crotty, I; Dasu, S; Dutta, S; Efron, J; Feyzi, F; Flood, K; Gray, L; Grogg, K S; Grothe, M; Hall-Wilton, R; Jaworski, M; Klabbers, P; Klukas, J; Lanaro, A; Lazaridis, C; Leonard, J; Loveless, R; Magrans de Abril, M; Mohapatra, A; Ott, G; Polese, G; Reeder, D; Savin, A; Smith, W H; Sourkov, A; Swanson, J; Weinberg, M; Wenman, D; Wensveen, M; White, A

    2010-01-01

    A large sample of cosmic ray events collected by the CMS detector is exploited to measure the specific energy loss of muons in the lead tungstate of the electromagnetic calorimeter. The measurement spans a momentum range from 5 GeV/c to 1 TeV/c. The results are consistent with the expectations over the entire range. The calorimeter energy scale, set with 120 GeV/c electrons, is validated down to the sub-GeV region using energy deposits, of order 100 MeV, associated with low-momentum muons. The muon critical energy in lead tungstate is measured to be 160+5/-6 plus or minus 8 GeV, in agreement with expectations. This is the first experimental determination of muon critical energy.

  17. Formulae for the secondary electron yield and total stopping power ...

    Indian Academy of Sciences (India)

    2Department of Electrical and Biological Physics, Kwangwoon University, 20 Kwangwoon-gil, ..... sample preparation techniques can lead to different ... talline orientation, contamination or submonolayer on the surface of foreign species; a.

  18. Study of the stopping power of various filters

    International Nuclear Information System (INIS)

    Madelaine, G.

    1964-01-01

    The first part is devoted to a study of aerosols obtained from the combustion of various smoke-producing compounds. A trial aerosol of which the size distribution is the closest possible to that of atmospheric dusts has been defined. The efficiency of various filters has been determined for successive increments of the dimensions and not for the whole range of its diameter distribution. The variation in the efficiency of the filtering layers as a function of the filtering speed and particle size has been studied for aerosols having particle diameters of over 0.3 μ. The second part describes an original method for measuring the efficiency of filters for ultra-fine particles (under 0.1 μ) using the fixation properties of radioactive atoms resulting from the decay of thoron. (author) [fr

  19. Lifespan changes in global and selective stopping and performance adjustments

    Directory of Open Access Journals (Sweden)

    Maria Christina Van De Laar

    2011-12-01

    Full Text Available This study examined stopping and performance adjustments in four age groups (M ages: 8, 12, 21, and 76 years. All participants performed on three tasks, a standard two-choice task and the same task in which stop-signal trials were inserted requiring either the suppression of the response activated by the choice stimulus (global stop task or the suppression of the response when one stop signal was presented but not when the other stop signal occurred (selective stop task. The results showed that global stopping was faster than selective stopping in all age groups. Global stopping matured more rapidly than selective stopping. The developmental gain in stopping was considerably more pronounced compared to the loss observed during senescence. All age groups slowed the response on trials without a stop signal in the stop task compared to trials in the choice task, the elderly in particular. In addition, all age groups slowed on trials following stop-signal trials, except the elderly who did not slow following successful inhibits. By contrast, the slowing following failed inhibits was disproportionally larger in the elderly compared to young adults. Finally, sequential effects did not alter the pattern of performance adjustments. The results were interpreted in terms of developmental change in the balance between proactive and reactive control.

  20. Lifespan Changes in Global and Selective Stopping and Performance Adjustments

    Science.gov (United States)

    van de Laar, Maria C.; van den Wildenberg, Wery P. M.; van Boxtel, Geert J. M.; van der Molen, Maurits W.

    2011-01-01

    This study examined stopping and performance adjustments in four age groups (M ages: 8, 12, 21, and 76 years). All participants performed on three tasks, a standard two-choice task and the same task in which stop-signal trials were inserted requiring either the suppression of the response activated by the choice stimulus (global stop task) or the suppression of the response when one stop-signal was presented but not when the other stop-signal occurred (selective stop task). The results showed that global stopping was faster than selective stopping in all age groups. Global stopping matured more rapidly than selective stopping. The developmental gain in stopping was considerably more pronounced compared to the loss observed during senescence. All age groups slowed the response on trials without a stop-signal in the stop task compared to trials in the choice task, the elderly in particular. In addition, all age groups slowed on trials following stop-signal trials, except the elderly who did not slow following successful inhibits. By contrast, the slowing following failed inhibits was disproportionally larger in the elderly compared to young adults. Finally, sequential effects did not alter the pattern of performance adjustments. The results were interpreted in terms of developmental change in the balance between proactive and reactive control. PMID:22180746

  1. Stop feeling: Inhibition of emotional interference following stop-signal trials

    OpenAIRE

    Eyal eKalanthroff; Noga eCohen; Avishai eHenik

    2013-01-01

    Although a great deal of literature has been dedicated to the mutual links between emotion and the selective attention component of executive control, there is very little data regarding the links between emotion and the inhibitory component of executive control. In the current study we employed an emotional stop-signal task in order to examine whether emotion modulates and is modulated by inhibitory control. Results replicated previous findings showing reduced inhibitory control [longer stop...

  2. Confessions of a Librarian or: How I Learned to Stop Worrying and Love Google

    Science.gov (United States)

    Gunnels, Claire B.; Sisson, Amy

    2009-01-01

    Have you ever stopped to think about life before Google? We will make the argument that Google is the first manifestation of Web 2.0, of the power and promise of social networking and the ubiquitous wiki. We will discuss the positive influence of Google and how Google and other social networking tools afford librarians leading-edge technologies…

  3. Experimental study on the influence of charge exchange on the stopping power in the interaction of chlorine with a gas and a deuterium plasma; Etude experimentale de l`influence des echanges de charges sur le pouvoir d`arret dans l`interaction d`ions chlore avec un gaz et un plasma de deuterium

    Energy Technology Data Exchange (ETDEWEB)

    Nectoux, Marie [Inst. de Physique Nucleaire, Paris-11 Univ., 91 - Orsay (France)

    1998-01-06

    This thesis is placed in the context of the physics of energy deposition of a multicharged heavy ion beam in matter at intermediate energies. The experiment gave measurements of energy loss as a function of final charge state for chlorine ions at 1.7 MeV/u in deuterium gas or plasma. In this way, we explore the influence of charge state evolution, depending on experimentally measured capture and ionization cross sections and the electron density of the target, on energy loss. The target is cylindrical and enclosed by two fast valves. The plasma is created in the gas by a discharge, which induces a magnetic perturbation of the beam (lens effect). This effect induces a divergent and misaligned outgoing beam. A simulation including charge state and velocity evolution of the projectile in flight in the magnetic field has been made in order to optimize beam analysis, to reach a precision better than 10{sup -3} in energy measurement. This study led to removal of the target to the `Split Pole`, a refocusing magnetic spectrometer. The first results obtained clearly show the dependence of energy loss on exit charge and especially on its evolution in the target. This is explained in terms of the lengths covered by the projectile in its successive charge states in the target, which depends on target electron density and the medium considered. In plasma, we observed an energy distribution with exit charge twice that observed in gas, because of a strong decrease of charge exchange. A comparison of data obtained in gas with stopping power calculated from Bethe-Bloch-Barkas theory leads to the necessity of including spatial extension of the projectile charge in the theory. (author) 81 refs., 62 figs., 5tabs.

  4. Single start multiple stop time digitizer

    International Nuclear Information System (INIS)

    Deshpande, P.A.; Mukhopadhyay, P.K.; Gopalakrishnan, K.R.

    1997-01-01

    A single start multiple stop time digitizer has been developed which can digitize the time between a start pulse and multiple stop pulses. The system has been designed as a PC add on card. The resolution of the instrument is 10 nSecs and the maximum length of time that it can measure is 1.28 milliseconds. Apart from time digitization, it can also resolve the height of the incoming pulses into 64 levels. After each input pulse the system dead time is less than 300 nSecs. The driver software for this card has been developed on DOS platform. It uses graphical user interface to provide a user friendly environment. The system is intended to be used in time of flight mass spectroscopy experiments. It can also be used for time of flight experiments in nuclear physics. (author). 2 figs

  5. Finite Optimal Stopping Problems: The Seller's Perspective

    Science.gov (United States)

    Hemmati, Mehdi; Smith, J. Cole

    2011-01-01

    We consider a version of an optimal stopping problem, in which a customer is presented with a finite set of items, one by one. The customer is aware of the number of items in the finite set and the minimum and maximum possible value of each item, and must purchase exactly one item. When an item is presented to the customer, she or he observes its…

  6. The TRIUMF stopped π-μ channel

    International Nuclear Information System (INIS)

    Al-Qazzaz, N.M.M.; Beer, G.A.; Mason, G.R.

    1980-01-01

    The TRIUMF π-μ channel (M9) is described and the measured optical paramters are compared with design values. Measured beam characteristics of pions and muons for several different momenta are reported for protons incident on Be and Cu production targets. A beam of cloud muons at the channel momentum, from π decays near the production target, has been obtained having a high stopping density and small spot size. (auth)

  7. Spectroscopy of hypernuclei with stopped kaons

    International Nuclear Information System (INIS)

    Tamura, H.; Brueckner, W.; Doebbeling, H.

    1987-09-01

    Pion momentum spectra from K - absorption at rest on various nuclear targets were measured by means of a magnetic spectrometer with wide momentum range (100 ∼ 300 MeV/c). The ground state of Σ - hypernucleus, if well bound with a narrow width, is expected to be populated in 12 C(stopped K - , π + ) inclusive (untagged) spectrum, but such a peak was not observed. The spectrum is compared with the DWIA calculations by Morimatsu and Yazaki, indicating that the depth of the nuclear potential of Σ - is shallower than 12 MeV, and that its imaginary part is larger than 5 MeV if the potential depth is about 10 MeV. In the 12 C(stopped K - , π - ) spectrum, the ground state ((p3/2) n -1 (s1/2) Λ ) and the excited states ((p3/2) n -1 (p) Λ ) of Λ 12 C were observed, and their formation probabilities were roughly in agreement with the results of DWIA calculations. In the π - spectra on 12 C, 9 Be, and 7 Li targets a distinct peak was observed at 132.1 ± 0.7 MeV/c. It is ascribed to π - from the mesic decay of Λ 4 H; Λ 4 H → 4 He π - . The formation probability of Λ 4 H on C, Be, or Li target is much larger than those of the discrete states of Λ 12 C via the direct (stopped K - , π - ) reaction. (author)

  8. Help Stop the Flu | NIH MedlinePlus the Magazine

    Science.gov (United States)

    ... page please turn Javascript on. Feature: Flu Shot Help Stop the Flu Past Issues / Winter 2011 Table ... CDC recommends that Americans do the following to help stop the flu: Cover nose and mouth with ...

  9. CDC Vital Signs: New Hope for Stopping HIV

    Science.gov (United States)

    ... 27 MB] Read the MMWR Science Clips New Hope for Stopping HIV Testing and Medical Care Save ... acquired immunodeficiency syndrome) and early death. There's new hope today for stopping HIV in the US. Medicines ( ...

  10. Optimal Stopping and Policyholder Behaviour in Life Insurance

    DEFF Research Database (Denmark)

    Gad, Kamille Sofie Tågholt

    . Below, I give a brief overview of the results of each of the chapters. A more thorough overview is presented in Chapter 1. In Chapter 2 we consider a general geometric Lévy process and solve the non-linear optimal stopping problem of maximizing the variance at the stopping time. For solving this problem...... we solve an auxiliary quadratic optimal stopping problem. We show that the solution to maximizing variance depends on whether randomized stopping times are included in the set of stopping times we maximize over. For some problems the inclusion of randomized stopping times increase the value function...... and for some it does not. Even when the value function is not affected by inclusion of randomized stopping times, a solution may be easier to identify when they are. In Chapter 3 we consider the non-linear optimal stopping problem of maximizing the mean minus a positive constant times the variance...

  11. Intelligent Bus Stops in the Flexible Bus Systems

    OpenAIRE

    Razi Iqbal; Muhammad Usman Ghani

    2014-01-01

    The purpose of this paper is to discuss Intelligent Bus Stops in a special Demand Responsive Transit (DRT), the Flexible Bus System. These Intelligent Bus Stops are more efficient and information rich than Traditional Bus Stops. The real time synchronization of the Flexible Bus System makes it unique as compared to Traditional Bus Systems. The Main concern is to make Bus Stops intelligent and information rich. Buses are informed about the no. of passengers waiting at the upcoming ...

  12. Start-Stop Test Procedures on the PEMFC Stack Level

    DEFF Research Database (Denmark)

    Mitzel, Jens; Nygaard, Frederik; Veltzé, Sune

    The test is addressed to investigate the influence on stack durability of a long stop followed by a restart of a stack. Long stop should be defined as a stop in which the anodic compartment is fully filled by air due to stack leakages. In systems, leakage level of the stack is low and time to fil...

  13. Biobjective Optimization and Evaluation for Transit Signal Priority Strategies at Bus Stop-to-Stop Segment

    Directory of Open Access Journals (Sweden)

    Rui Li

    2016-01-01

    Full Text Available This paper proposes a new optimization framework for the transit signal priority strategies in terms of green extension, red truncation, and phase insertion at the stop-to-stop segment of bus lines. The optimization objective is to minimize both passenger delay and the deviation from bus schedule simultaneously. The objective functions are defined with respect to the segment between bus stops, which can include the adjacent signalized intersections and downstream bus stops. The transit priority signal timing is optimized by using a biobjective optimization framework considering both the total delay at a segment and the delay deviation from the arrival schedules at bus stops. The proposed framework is evaluated using a VISSIM model calibrated with field traffic volume and traffic signal data of Caochangmen Boulevard in Nanjing, China. The optimized TSP-based phasing plans result in the reduced delay and improved reliability, compared with the non-TSP scenario under the different traffic flow conditions in the morning peak hour. The evaluation results indicate the promising performance of the proposed optimization framework in reducing the passenger delay and improving the bus schedule adherence for the urban transit system.

  14. Experimental discrimination of ion stopping models near the Bragg peak in highly ionized matter

    Science.gov (United States)

    Cayzac, W.; Frank, A.; Ortner, A.; Bagnoud, V.; Basko, M. M.; Bedacht, S.; Bläser, C.; Blažević, A.; Busold, S.; Deppert, O.; Ding, J.; Ehret, M.; Fiala, P.; Frydrych, S.; Gericke, D. O.; Hallo, L.; Helfrich, J.; Jahn, D.; Kjartansson, E.; Knetsch, A.; Kraus, D.; Malka, G.; Neumann, N. W.; Pépitone, K.; Pepler, D.; Sander, S.; Schaumann, G.; Schlegel, T.; Schroeter, N.; Schumacher, D.; Seibert, M.; Tauschwitz, An.; Vorberger, J.; Wagner, F.; Weih, S.; Zobus, Y.; Roth, M.

    2017-01-01

    The energy deposition of ions in dense plasmas is a key process in inertial confinement fusion that determines the α-particle heating expected to trigger a burn wave in the hydrogen pellet and resulting in high thermonuclear gain. However, measurements of ion stopping in plasmas are scarce and mostly restricted to high ion velocities where theory agrees with the data. Here, we report experimental data at low projectile velocities near the Bragg peak, where the stopping force reaches its maximum. This parameter range features the largest theoretical uncertainties and conclusive data are missing until today. The precision of our measurements, combined with a reliable knowledge of the plasma parameters, allows to disprove several standard models for the stopping power for beam velocities typically encountered in inertial fusion. On the other hand, our data support theories that include a detailed treatment of strong ion-electron collisions. PMID:28569766

  15. Stop feeling: inhibition of emotional interference following stop-signal trials.

    Science.gov (United States)

    Kalanthroff, Eyal; Cohen, Noga; Henik, Avishai

    2013-01-01

    Although a great deal of literature has been dedicated to the mutual links between emotion and the selective attention component of executive control, there is very little data regarding the links between emotion and the inhibitory component of executive control. In the current study we employed an emotional stop-signal task in order to examine whether emotion modulates and is modulated by inhibitory control. Results replicated previous findings showing reduced inhibitory control [longer stop-signal reaction time (SSRT)] following negative, compared to neutral pictures. Most importantly, results show decreased emotional interference following stop-signal trials. These results show that the inhibitory control component of executive control can serve to decrease emotional effects. We suggest that inhibitory control and emotion have a two-way connection in which emotion disrupts inhibitory control and activation of inhibitory control disrupts emotion.

  16. Stop feeling: Inhibition of emotional interference following stop-signal trials

    Directory of Open Access Journals (Sweden)

    Eyal eKalanthroff

    2013-03-01

    Full Text Available Although a great deal of literature has been dedicated to the mutual links between emotion and the selective attention component of executive control, there is very little data regarding the links between emotion and the inhibitory component of executive control. In the current study we employed an emotional stop-signal task in order to examine whether emotion modulates and is modulated by inhibitory control. Results replicated previous findings showing reduced inhibitory control (longer stop-signal reaction time following negative, compared to neutral pictures. Most importantly, results show decreased emotional interference following stop-signal trials. These results show that the inhibitory control component of executive control can serve to decrease emotional effects. We suggest that inhibitory control and emotion have a two-way connection in which emotion disrupts inhibitory control and activation of inhibitory control disrupts emotion.

  17. USABC Development of 12 Volt Battery for Start-Stop Application: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Tataria, H.; Gross, O.; Bae, C.; Cunningham, B.; Barnes, J. A.; Deppe, J.; Neubauer, J.

    2015-02-01

    Global automakers are accelerating the development of fuel efficient vehicles, as a part of meeting regional regulatory CO2 emissions requirements. The micro hybrid vehicles with auto start-stop functionality are considered economical solutions for the stringent European regulations. Flooded lead acid batteries were initially considered the most economical solution for idle-stop systems. However, the dynamic charge acceptance (DCA) at lower state-of-charge (SOC) was limiting the life of the batteries. While improved lead-acid batteries with AGM and VRLA features have improved battery longevity, they do not last the life of the vehicle. The United States Advanced Battery Consortium (or USABC, a consortium of GM, Ford, and Chrysler) analyzed energy storage needs for a micro hybrid automobile with start-stop capability, and with a single power source. USABC has analyzed the start-stop behaviors of many drivers and has developed the requirements for the start-stop batteries (Table 3). The testing procedures to validate the performance and longevity were standardized and published. The guideline for the cost estimates calculations have also been provided, in order to determine the value of the newly developed modules. The analysis effort resulted in a set of requirements which will help the battery manufacturers to develop a module to meet the automotive Original Equipment Manufacturers (OEM) micro hybrid vehicle requirements. Battery developers were invited to submit development proposals and two proposals were selected for 50% cost share with USABC/DOE.

  18. End-Stop Exemplar Based Recognition

    DEFF Research Database (Denmark)

    Olsen, Søren I.

    2003-01-01

    An approach to exemplar based recognition of visual shapes is presented. The shape information is described by attributed interest points (keys) detected by an end-stop operator. The attributes describe the statistics of lines and edges local to the interest point, the position of neighboring int...... interest points, and (in the training phase) a list of recognition names. Recognition is made by a simple voting procedure. Preliminary experiments indicate that the recognition is robust to noise, small deformations, background clutter and partial occlusion....

  19. Jojoba could stop the desert creep

    Energy Technology Data Exchange (ETDEWEB)

    1982-03-25

    The Sahara desert is estimated to be expanding at a rate of 5km a year. The Sudanese government is experimenting with jojoba in six different regions as the bush has the potential to stop this ''desert creep''. The plant, a native to Mexico, is long known for its resistance to drought and for the versatile liquid wax that can be extracted from its seeds. It is estimated that one hectare of mature plants could produce 3000 kg of oil, currently selling at $50 per litre, and so earn valuable foreign currency.

  20. Early Stop Criterion from the Bootstrap Ensemble

    DEFF Research Database (Denmark)

    Hansen, Lars Kai; Larsen, Jan; Fog, Torben L.

    1997-01-01

    This paper addresses the problem of generalization error estimation in neural networks. A new early stop criterion based on a Bootstrap estimate of the generalization error is suggested. The estimate does not require the network to be trained to the minimum of the cost function, as required...... by other methods based on asymptotic theory. Moreover, in contrast to methods based on cross-validation which require data left out for testing, and thus biasing the estimate, the Bootstrap technique does not have this disadvantage. The potential of the suggested technique is demonstrated on various time...

  1. Frame by frame stop motion non-traditional approaches to stop motion animation

    CERN Document Server

    Gasek, Tom

    2011-01-01

    In a world that is dominated by computer images, alternative stop motion techniques like pixilation, time-lapse photography and down-shooting techniques combined with new technologies offer a new, tangible and exciting approach to animation. With over 25 years professional experience, industry veteran, Tom Gasek presents a comprehensive guide to stop motion animation without the focus on puppetry or model animation. With tips, tricks and hands-on exercises, Frame by Frame will help both experienced and novice filmmakers get the most effective results from this underutilized branch of animation

  2. Interaction between two stopped light pulses

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yi-Hsin, E-mail: yhchen920@gmail.com; Lee, Meng-Jung, E-mail: yhchen920@gmail.com; Hung, Weilun, E-mail: yhchen920@gmail.com; Yu, Ite A., E-mail: yu@phys.nthu.edu.tw [Department of Physics and Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Chen, Ying-Cheng [Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan and Department of Physics and Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Chen, Yong-Fan [Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan (China)

    2014-03-05

    The efficiency of a nonlinear optical process is proportional to the interaction time. We report a scheme of all-optical switching based on two motionless light pulses via the effect of electromagnetically induced transparency. One pulse was stopped as the stationary light pulse (SLP) and the other was stopped as stored light. The time of their interaction via the medium can be prolonged and, hence, the optical nonlinearity is greatly enhanced. Using a large optical density (OD) of 190, we achieved a very long interaction time of 6.9 μs. This can be analogous to the scheme of trapping light pulses by an optical cavity with a Q factor of 8×10{sup 9}. With the approach of using moving light pulses in the best situation, a switch can only be activated at 2 photons per atomic absorption cross section. With the approach of employing a SLP and a stored light pulse, a switch at only 0.56 photons was achieved and the efficiency is significantly improved. Moreover, the simulation results are in good agreement with the experimental data and show that the efficiency can be further improved by increasing the OD of the medium. Our work advances the technology in quantum information manipulation utilizing photons.

  3. Contrast effects on stop consonant identification.

    Science.gov (United States)

    Diehl, R L; Elman, J L; McCusker, S B

    1978-11-01

    Changes in the identification of speech sounds following selective adaptation are usually attributed to a reduction in sensitivity of auditory feature detectors. An alternative explanation of these effects is based on the notion of response contrast. In several experiments, subjects identified the initial segment of synthetic consonant-vowel syllables as either the voiced stop [b] or the voiceless stop [ph]. Each test syllable had a value of voice onset time (VOT) that placed it near the English voiced-voiceless boundary. When the test syllables were preceded by a single clear [b] (VOT = -100 msec), subjects tended to identify them as [ph], whereas when they were preceded by an unambiguous [ph] (VOT = 100 msec), the syllables were predominantly labeled [b]. This contrast effect occurred even when the contextual stimuli were velar and the test stimuli were bilabial, which suggests a featural rather than a phonemic basis for the effect. To discount the possibility that these might be instances of single-trial sensory adaptation, we conducted a similar experiment in which the contextual stimuli followed the test items. Reliable contrast effects were still obtained. In view of these results, it appears likely that response contrast accounts for at least some component of the adaptation effects reported in the literature.

  4. Interaction between two stopped light pulses

    International Nuclear Information System (INIS)

    Chen, Yi-Hsin; Lee, Meng-Jung; Hung, Weilun; Yu, Ite A.; Chen, Ying-Cheng; Chen, Yong-Fan

    2014-01-01

    The efficiency of a nonlinear optical process is proportional to the interaction time. We report a scheme of all-optical switching based on two motionless light pulses via the effect of electromagnetically induced transparency. One pulse was stopped as the stationary light pulse (SLP) and the other was stopped as stored light. The time of their interaction via the medium can be prolonged and, hence, the optical nonlinearity is greatly enhanced. Using a large optical density (OD) of 190, we achieved a very long interaction time of 6.9 μs. This can be analogous to the scheme of trapping light pulses by an optical cavity with a Q factor of 8×10 9 . With the approach of using moving light pulses in the best situation, a switch can only be activated at 2 photons per atomic absorption cross section. With the approach of employing a SLP and a stored light pulse, a switch at only 0.56 photons was achieved and the efficiency is significantly improved. Moreover, the simulation results are in good agreement with the experimental data and show that the efficiency can be further improved by increasing the OD of the medium. Our work advances the technology in quantum information manipulation utilizing photons

  5. Nuclear power

    International Nuclear Information System (INIS)

    Anon.

    1980-01-01

    The committee concludes that the nature of the proliferation problem is such that even stopping nuclear power completely could not stop proliferation completely. Countries can acquire nuclear weapons by means independent of commercial nuclear power. It is reasonable to suppose if a country is strongly motivated to acquire nuclear weapons, it will have them by 2010, or soon thereafter, no matter how nuclear power is managed in the meantime. Unilateral and international diplomatic measures to reduce the motivations that lead to proliferation should be high on the foreign policy agenda of the United States. A mimimum antiproliferation prescription for the management of nuclear power is to try to raise the political barriers against proliferation through misuse of nuclear power by strengthening the Non-Proliferation Treaty, and to seek to raise the technological barriers by placing fuel-cycle operations involving weapons-usable material under international control. Any such measures should be considered tactics to slow the spread of nuclear weapons and thus earn time for the exercise of statesmanship. The committee concludes the following about technical factors that should be considered in formulating nuclear policy: (1) rate of growth of electricity use is a primary factor; (2) growth of conventional nuclear power will be limited by producibility of domestic uranium sources; (3) greater contribution of nuclear power beyond 400 GWe past the year 2000 can only be supported by advanced reactor systems; and (4) several different breeder reactors could serve in principle as candidates for an indefinitely sustainable source of energy

  6. Intelligent Bus Stops in the Flexible Bus Systems

    Directory of Open Access Journals (Sweden)

    Razi Iqbal

    2014-09-01

    Full Text Available The purpose of this paper is to discuss Intelligent Bus Stops in a special Demand Responsive Transit (DRT, the Flexible Bus System. These Intelligent Bus Stops are more efficient and information rich than Traditional Bus Stops. The real time synchronization of the Flexible Bus System makes it unique as compared to Traditional Bus Systems. The Main concern is to make Bus Stops intelligent and information rich. Buses are informed about the no. of passengers waiting at the upcoming Bus Stops. If there are no passengers to ride or get off on upcoming Bus Stop, the Bus can skip that Bus Stop and head towards the next Bus Stop where passenger is waiting, which will decrease the ride time of the passengers on the Bus and also the wait time of the passengers waiting on the upcoming Bus Stops. Providing more information at Bus Stops about the Destination (Time to Destination, Distance to Destination etc. and Buses (Bus Location, Arrival Time of Bus etc. makes it easier for the passengers to decide whether to ride a particular Bus or not.

  7. Remune trial will stop; new trials planned.

    Science.gov (United States)

    James, J S

    1999-05-21

    A clinical trial using remune, the anti-HIV vaccine developed by the late Dr. Jonas Salk, has been ended. The study is a clinical-endpoint trial which looks for statistically significant differences in AIDS sickness or death between patients who add remune to their treatment regimens versus those who use a placebo. Agouron Pharmaceuticals and the Immune Response Corporation who were conducting the trial announced their decision to stop it after an analysis by the Data Safety Monitoring Board. No differences in clinical endpoints were found and it was projected that continuing the trial would likely not find any. The companies are now planning two new Phase III trials using viral load testing rather than clinical endpoints as study criteria.

  8. Stop Lepton Associated Production at Hadron Colliders

    CERN Document Server

    Alves, A; Plehn, Tilman

    2003-01-01

    At hadron colliders, the search for R-parity violating supersymmetry can probe scalar masses beyond what is covered by pair production processes. We evaluate the next-to-leading order SUSY-QCD corrections to the associated stop or sbottom production with a lepton through R-parity violating interactions. We show that higher order corrections render the theoretical predictions more stable with respect to variations of the renormalization and factorization scales and that the total cross section is enhanced by a factor up to 70% at the Tevatron and 50% at the LHC. We investigate in detail how the heavy supersymmetric states decouple from the next-to-leading order process, which gives rise to a theory with an additional scalar leptoquark. In this scenario the inclusion of higher order QCD corrections increases the Tevatron reach on leptoquark masses by up to 40 GeV and the LHC reach by up to 200 GeV.

  9. The Novel Microwave Stop-Band Filter

    Directory of Open Access Journals (Sweden)

    R. E. Chernobrovkin

    2008-01-01

    Full Text Available The stop-band filter with the new band-rejection element is proposed. The element is a coaxial waveguide with the slot in the centre conductor. In the frame of this research, the numerical and experimental investigations of the amplitude-frequency characteristics of the filter are carried out. It is noted that according to the slot parameters the two typical resonances (half-wave and quarter-wave can be excited. The rejection band of the single element is defined by the width, depth, and dielectric filling of the slot. Fifth-order Chebyshev filter utilizing the aforementioned element is also synthesized, manufactured, and tested. The measured and simulated results are in good agreement. The experimental filter prototype exhibits the rejection band 0.86 GHz at the level −40 dB.

  10. OPTIMIZATION OF MAGNETIZATION AND MAGNATION REGIMES OF STOPPED THREE-PHASE SYNCHRONOUS MACHINE

    Directory of Open Access Journals (Sweden)

    V. A. VOLKOV

    2018-05-01

    Full Text Available Purpose. Investigation and optimization (minimization of electric energy losses in a stopped synchronous machine with a thyristor exciter under conditions of its magnetization and demagnetization. Methodology. Operator and variational calculus, mathematical analysis and simulation computer simulation. Findings. The mathematical description of the system under study is developed: "thyristor exciter – stopped synchronous machine", which represents the analytical dependencies for electromagnetic processes, as well as the total power and energy losses in the system under magnetization and demagnetization regimes of the synchronous machine. The optimal time functions for changing the flux linkages of the damper winding and the excitation current of the stopped synchronous machine, in which they are minimized by energy in the system under investigation when the machine is magnetized and demagnetized. The dependences of the total energy losses in the system under study on the durations of the magnetization and demagnetization times of the machine are calculated, and their comparison is compared for different types (linear, parabolic and proposed optimal of the trajectories of the change of the linkage, as well as for a linear and exponential change in the excitation current of the machine. Analytic dependencies are obtained using the calculations of electromagnetic and energy transient processes in the "thyristor exciter – stopped synchronous machine" system under the considered types of variation of flux linkage and excitation current of the machine. Originality. It consists in finding the optimal trajectories of the time variation of the excitation current of a stopped synchronous machine and the optimal durations of its magnetization and demagnetization times, which ensure minimization of energy losses in the system "thyristor exciter – stopped synchronous machine". Practical value. It consists in reducing unproductive energy losses in

  11. Stop Codon Reassignment in the Wild

    Energy Technology Data Exchange (ETDEWEB)

    Ivanova, Natalia [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; Schwientek, Patrick [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; Tripp, H. James [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; Rinke, Christian [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; Pati, Amrita [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; Huntemann, Marcel [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; Visel, Axel [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; Woyke, Tanja [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; Kyrpides, Nikos [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; Rubin, Edward [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.

    2014-03-21

    Since the discovery of the genetic code and protein translation mechanisms (1), a limited number of variations of the standard assignment between unique base triplets (codons) and their encoded amino acids and translational stop signals have been found in bacteria and phages (2-3). Given the apparent ubiquity of the canonical genetic code, the design of genomically recoded organisms with non-canonical codes has been suggested as a means to prevent horizontal gene transfer between laboratory and environmental organisms (4). It is also predicted that genomically recoded organisms are immune to infection by viruses, under the assumption that phages and their hosts must share a common genetic code (5). This paradigm is supported by the observation of increased resistance of genomically recoded bacteria to phages with a canonical code (4). Despite these assumptions and accompanying lines of evidence, it remains unclear whether differential and non-canonical codon usage represents an absolute barrier to phage infection and genetic exchange between organisms. Our knowledge of the diversity of genetic codes and their use by viruses and their hosts is primarily derived from the analysis of cultivated organisms. Advances in single-cell sequencing and metagenome assembly technologies have enabled the reconstruction of genomes of uncultivated bacterial and archaeal lineages (6). These initial findings suggest that large scale systematic studies of uncultivated microorganisms and viruses may reveal the extent and modes of divergence from the canonical genetic code operating in nature. To explore alternative genetic codes, we carried out a systematic analysis of stop codon reassignments from the canonical TAG amber, TGA opal, and TAA ochre codons in assembled metagenomes from environmental and host-associated samples, single-cell genomes of uncultivated bacteria and archaea, and a collection of phage sequences

  12. 20 CFR 662.430 - Under what conditions may One-Stop operators designated to operate in a One-Stop delivery system...

    Science.gov (United States)

    2010-04-01

    ... designated to operate in a One-Stop delivery system established prior to the enactment of WIA be designated... DESCRIPTION OF THE ONE-STOP SYSTEM UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT One-Stop Operators § 662.430 Under what conditions may One-Stop operators designated to operate in a One-Stop delivery system...

  13. Design of permanent block stopping to resist strata convergence

    Energy Technology Data Exchange (ETDEWEB)

    Ray, R.E.

    1985-11-01

    Conventional concrete block plastered with a cementitious coating is the most common material used in the construction of permanent stoppings to direct airflow in underground mines in the US. All mines experience various degrees of strata convergence depending on depth of overburden, geological conditions, and type of roof support employed. Strata convergence will cause cracks and joint openings in masonry stoppings, resulting in significant air leakage losses. Where strata convergence is severe, complete structural failure of the stopping can ultimately occur. Reconstruction of damaged or destroyed stoppings adds expensive overheads to mining operations, and even greater expenses are incurred from the additional fan horsepower required to overcome leakage losses. Ideally, a stopping should maintain high resistance to airflow while yielding to strata convergence. By properly incorporating a polyisocyanurate rigid foam material within the masonry block structure, stopping service life can be increased in mines experiencing strata convergence problems such as floor heave, roof loading, and lateral rib movement.

  14. Stopping test of iterative methods for solving PDE

    International Nuclear Information System (INIS)

    Wang Bangrong

    1991-01-01

    In order to assure the accuracy of the numerical solution of the iterative method for solving PDE (partial differential equation), the stopping test is very important. If the coefficient matrix of the system of linear algebraic equations is strictly diagonal dominant or irreducible weakly diagonal dominant, the stopping test formulas of the iterative method for solving PDE is proposed. Several numerical examples are given to illustrate the applications of the stopping test formulas

  15. On poisson-stopped-sums that are mixed poisson

    OpenAIRE

    Valero Baya, Jordi; Pérez Casany, Marta; Ginebra Molins, Josep

    2013-01-01

    Maceda (1948) characterized the mixed Poisson distributions that are Poisson-stopped-sum distributions based on the mixing distribution. In an alternative characterization of the same set of distributions here the Poisson-stopped-sum distributions that are mixed Poisson distributions is proved to be the set of Poisson-stopped-sums of either a mixture of zero-truncated Poisson distributions or a zero-modification of it. Peer Reviewed

  16. Research of the stopping distance for different road conditions

    Directory of Open Access Journals (Sweden)

    Daniel LYUBENOV

    2011-01-01

    Full Text Available In this paper a modern method for determination of stopping distance is represented. Application of the non-contact VBOX 3i 100Hz GPS Data Logger speed and distance measurement system is represented. A description of the total stopping distance of vehicle main components - driver reaction time, vehicle reaction time and vehicle braking capability has been made. Research of the total stopping distance of a vehicle for different road conditions has been made. The results for the stopping distance can be very useful in the expert practice.

  17. Class, geography, and the consumerist turn: UNITE and the Stop Sweatshops Campaign

    OpenAIRE

    Rebecca Johns; Leyla Vural

    2000-01-01

    The late 20th century has seen unions in the industrial and postindustrial countries retrench and struggle to develop new strategies and tactics in the face of a changing political economy. A challenge to the traditional conceptions of the appropriate place and scope of union activity comes from the Union of Needletrades, Industrial and Textile Employees and its innovative leadership in the US-based Stop Sweatshops Campaign. Based on an analysis of the shifting locus of power in the garment i...

  18. Stopping the greenhouse effect - recommendations submitted by the Bundestag Enquete Commission

    International Nuclear Information System (INIS)

    Bach, W.

    1991-01-01

    Details are given about the factors which influence the greenhouse effect and about the impact of the greenhouse effect on the climate. The strategy developed by the enquete commission for the Federal Republic of Germany is essentially based on the international and the EC recommendations for stopping the additional greenhouse effect and for reducing the emission of power-generation trace gases which affect the climate. Different scenarios are analyzed to evaluate the recommended measures. (DG) [de

  19. VRLA automotive batteries for stop&go and dual battery systems

    Science.gov (United States)

    May, G. J.; Calasanzio, D.; Aliberti, R.

    The electrical power requirements for vehicles are continuing to increase and evolve. A substantial amount of effort has been directed towards the development of 36/42 V systems as a route to higher power with reduced current levels but high implementation costs have resulted in the introduction of these systems becoming deferred. In the interim, however, alternator power outputs at 14 V are being increased substantially and at the same time the requirements for batteries are becoming more intensive. In particular, stop&go systems and wire-based vehicle systems are resulting in new demands. For stop&go, the engine is stopped each time the vehicle comes to rest and is restarted when the accelerator is pressed again. This results in an onerous duty cycle with many shallow discharge cycles. Flooded lead-acid batteries cannot meet this duty cycle and valve-regulated lead-acid (VRLA) batteries are needed to meet the demands that are applied. For wire-based systems, such as brake-by-wire or steer-by-wire, electrical power has become more critical and although the alternator and battery provide double redundancy, triple redundancy with a small reserve battery is specified. In this case, a small VRLA battery can be used and is optimised for standby service rather than for repeated discharges. The background to these applications is considered and test results under simulated operating conditions are discussed. Good performance can be obtained in batteries adapted for both applications. Battery management is also critical for both applications: in stop&go service, the state-of-charge (SOC) and state-of-health (SOH) need to be monitored to ensure that the vehicle can be restarted; for reserve or back-up batteries, the SOC and SOH are monitored to verify that the battery is always capable of carrying out the duty cycle if required. Practical methods of battery condition monitoring will be described.

  20. Enhanced stopping of macro-particles in particle-in-cell simulations

    International Nuclear Information System (INIS)

    May, J.; Tonge, J.; Ellis, I.; Mori, W. B.; Fiuza, F.; Fonseca, R. A.; Silva, L. O.; Ren, C.

    2014-01-01

    We derive an equation for energy transfer from relativistic charged particles to a cold background plasma appropriate for finite-size particles that are used in particle-in-cell simulation codes. Expressions for one-, two-, and three-dimensional particles are presented, with special attention given to the two-dimensional case. This energy transfer is due to the electric field of the wake set up in the background plasma by the relativistic particle. The enhanced stopping is dependent on the q 2 /m, where q is the charge and m is the mass of the relativistic particle, and therefore simulation macro-particles with large charge but identical q/m will stop more rapidly. The stopping power also depends on the effective particle shape of the macro-particle. These conclusions are verified in particle-in-cell simulations. We present 2D simulations of test particles, relaxation of high-energy tails, and integrated fast ignition simulations showing that the enhanced drag on macro-particles may adversely affect the results of these simulations in a wide range of high-energy density plasma scenarios. We also describe a particle splitting algorithm which can potentially overcome this problem and show its effect in controlling the stopping of macro-particles

  1. A nurse-led 'stop smoking' initiative.

    Science.gov (United States)

    McGowan, E; MacAuley, D; Anderson, U

    A one-week smoking awareness initiative and subsequent audit in a general practice are described. All patients attending morning surgery during the study period were offered the opportunity to discuss smoking habits at a smoking awareness clinic: 84 smokers attended. They were interviewed by the practice preventive care nurse who took a smoking history, monitored carbon monoxide (CO Hb) levels and offered a follow-up appointment. CO Hb provided immediate feedback on the effect of smoking and patients who smoked 20 or more cigarettes per day had an average CO Hb of 16.1 per cent. Fifteen per cent of smokers made a commitment to stop smoking and agreed to attend follow-up clinics. A random sample (50) of attenders at the initial Smoking Awareness Clinic (84) were followed up by questionnaire six months later. There were 29 replies (58 per cent); 19 patients (65 per cent) found the visit to the clinic helpful, 14 (48 per cent) reduced the number of cigarettes they smoked, and 11 (38 per cent) altered some other aspect of their lifestyle, of whom four modified their diet and four increased exercise. Five patients claimed they had given up smoking.

  2. Towards the end of the technical stop

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    After several weeks of hard work, the short technical stop of the LHC accelerator is coming to an end. Following a very intense campaign to repair and retest many thousand high voltage connectors, the upgraded magnet protection system is being commissioned. During this period, the current in the main dipole and quadrupole magnets is carefully increased up to 6kA, required to collide protons at 7TeV centre-of-mass energy. This has been achieved for most of the sectors.   The parameters of the upgraded magnet protection system are accurately calibrated. This operation is needed in order for the magnet protection system to be triggered only when a real problem occurs. The system is now able to detect a transition from superconducting to normal conducting state of the superconducting cable joints between magnets, a necessary condition to operate the magnet system above 2kA. Highly accurate measurements of the joint resistances have been performed by stepping up the current to 5kA. The magnets and the...

  3. 49 CFR 37.201 - Intermediate and rest stops.

    Science.gov (United States)

    2010-10-01

    ... wheelchair, shall be permitted to leave and return to the bus on the same basis as other passengers. The... passenger to get on and off the bus at the stop (e.g., operate the lift and provide assistance with... DISABILITIES (ADA) Over-the-Road Buses (OTRBs) § 37.201 Intermediate and rest stops. (a) Whenever an OTRB makes...

  4. Stop valve with automatic control and locking for nuclear reactors

    International Nuclear Information System (INIS)

    Chung, D.K.

    1980-01-01

    This invention generally concerns an automatic control and locking stop valve. Specifically it relates to the use of such a valve in a nuclear reactor of the type containing absorber elements supported by a fluid and intended for stopping the reactor in complete safety [fr

  5. Effect of Weight Transfer on a Vehicle's Stopping Distance.

    Science.gov (United States)

    Whitmire, Daniel P.; Alleman, Timothy J.

    1979-01-01

    An analysis of the minimum stopping distance problem is presented taking into account the effect of weight transfer on nonskidding vehicles and front- or rear-wheels-skidding vehicles. Expressions for the minimum stopping distances are given in terms of vehicle geometry and the coefficients of friction. (Author/BB)

  6. STOP4-7 Nederland. Resultaten 2010-2011

    NARCIS (Netherlands)

    Geijsen, L.; Veerman, J.W.; Bastiaanssen, I.L.W.

    2011-01-01

    STOP4-7 is een multimodale interventie voor kinderen van 4 tot 7 jaar met ernstige externaliserende gedragsproblemen en hun opvoeders en leerkrachten. Het doel van STOP4-7 is het aanleren en versterken van sociale en probleemoplossende vaardigheden en het verminderen van ongewenst gedrag. Daarvoor

  7. Note on measuring electronic stopping of slow ions

    Science.gov (United States)

    Sigmund, P.; Schinner, A.

    2017-11-01

    Extracting stopping cross sections from energy-loss measurements requires careful consideration of the experimental geometry. Standard procedures for separating nuclear from electronic stopping treat electronic energy loss as a friction force, ignoring its dependence on impact parameter. In the present study we find that incorporating this dependence has a major effect on measured stopping cross sections, in particular for light ions at low beam energies. Calculations have been made for transmission geometry, nuclear interactions being quantified by Bohr-Williams theory of multiple scattering on the basis of a Thomas-Fermi-Molière potential, whereas electronic interactions are characterized by Firsov theory or PASS code. Differences between the full and the restricted stopping cross section depend on target thickness and opening angle of the detector and need to be taken into account in comparisons with theory as well as in applications of stopping data. It follows that the reciprocity principle can be violated when checked on restricted instead of full electronic stopping cross sections. Finally, we assert that a seeming gas-solid difference in stopping of low-energy ions is actually a metal-insulator difference. In comparisons with experimental results we mostly consider proton data, where nuclear stopping is only a minor perturbation.

  8. Simulating fail-stop in asynchronous distributed systems

    Science.gov (United States)

    Sabel, Laura; Marzullo, Keith

    1994-01-01

    The fail-stop failure model appears frequently in the distributed systems literature. However, in an asynchronous distributed system, the fail-stop model cannot be implemented. In particular, it is impossible to reliably detect crash failures in an asynchronous system. In this paper, we show that it is possible to specify and implement a failure model that is indistinguishable from the fail-stop model from the point of view of any process within an asynchronous system. We give necessary conditions for a failure model to be indistinguishable from the fail-stop model, and derive lower bounds on the amount of process replication needed to implement such a failure model. We present a simple one-round protocol for implementing one such failure model, which we call simulated fail-stop.

  9. New stopping rules for dendrogram classification in TWINSPAN

    Directory of Open Access Journals (Sweden)

    Omid Esmailzadeh

    2015-12-01

    Full Text Available The aim of this study is to propose a modification of TWINSPAN algorithm with introducing new stopping rules for TWINSPAN. Modified TWINSPAN combines the analysis of heterogeneity of the clusters prior to each division to prevent the imposed divisions of homogeneous clusters and it also solved the limitation of classical TWINSPAN in which the number of clusters increases power of two. For this purpose, ecological groups of Box tree stands in Farim forests were classified with using classical and modified TWINSPAN basis of plant species cover percentage of 60 plots with 400 m2 surface area which were made by releve method (by consideration of indicator stand concept. In this relation, five different heterogeneity measures including Whittaker’s beta diversity and total inertia, Sorensen, Jaccard and Orlo´ci dissimilarity indices which representing diversity and distance indices respectively were involved. Sample plots were also classified from basis of topographical properties using cluster analysis with emphasizing Euclidean distance coefficient and Wards clustering method. Results showed that using of two sets of heterogeneity indices lead to different classification dendrograms. In this relation, results of Whittaker’s beta with total inertia as diversity indices were similar and the other three dissimilarity indices have shown similar behavior. Finally, our results reiterated that modified TWINSPAN did not alter the logic of the TWINSPAN classification, but it increased the flexibility of TWINSPAN dendrogram with changing the hierarchy of divisions in the final classification of ecological groups of Box tree stands in Farim forests.

  10. The global polio eradication initiative Stop Transmission of Polio (STOP) program - 1999-2013.

    Science.gov (United States)

    2013-06-21

    In 1988, the Global Polio Eradication Initiative (GPEI) was established through a partnership between the World Health Organization (WHO), Rotary International, CDC, and the United Nations Children's Fund (UNICEF). By 2012, the annual incidence of polio had decreased by >99%, compared with 1988, and the number of countries in which wild poliovirus (WPV) circulation has never been interrupted was reduced to three: Afghanistan, Nigeria, and Pakistan. However, because of the persistence of endemic WPV transmission and recurring outbreaks in polio-free countries after the original polio eradication target date of 2000, the World Health Assembly in 2012 declared the completion of polio eradication a programmatic emergency. A key component of GPEI is the Stop Transmission of Polio (STOP) program, which was developed and initiated by CDC with WHO in 1999 to mobilize additional human resources and technical assistance for countries affected by WPV transmission. During 1999-2013, 1,563 volunteers were identified, trained, and deployed for 2,221 assignments in 69 countries. The number of volunteers increased from 90-120 per year during 1999-2011 to 287 in 2012 and 378 in 2013, and the number of volunteer person-months in the field per year increased from 273 in 1999 to 1,456 in 2012. The STOP program has aided GPEI by strengthening the capacity of country-level immunization programs and by allowing a large cohort of volunteers to gain valuable field experience that prepares them well for subsequent work as staff members of WHO, UNICEF, and other public health agencies.

  11. Global warming: What should we do to stop or slow?

    International Nuclear Information System (INIS)

    Guenalp, B.

    2006-01-01

    Earth is warming much faster than had been predicted. 2005 was the warmest year on record, surpassing 1998. The multinational Arctic Climate Impact Assessment (ACIA) report recently concluded that in Alaska, western Canada, and eastern Russia, average temperatures have increased 3 to 4 degrees Celsius in the past 50 years. Rising temperatures have a dramatic impact on Arctic ice. Since 1978 Arctic sea ice area has shrunk by some 9 percent per decade, and thinned as well. There are three specific events especially worrisome and potentially imminent, although the time frames are a matter of dispute: dramatic sea level rise by the end of the century that would take tens of thousand years to reverse; widespread coral bleaching that could be damage the world's fisheries within three decades; and, within 200 years, a shutdown of the ocean current that moderates temperatures in northern Europe. Global warming is caused by human activities such as burning nature's vast store of coal, oil and nature gas which releases billions of tones carbon dioxide (CO 2 ) every year. If current trends continue, we will raise atmospheric CO 2 concentrations to double pre-industrial levels during this century. That will probably be enough to raise global temperatures by around 2 degree C to 5 degree C. Even if humans stop burning oil and coal tomorrow we have already spewed enough greenhouse gases into the atmosphere to cause temperatures to warm and sea levels to rise for at least another century. So what should we do? We can not continue drawing energy from fossil fuels and there is no chance that the renewable, wind, tide, and water power can provide enough energy and in time. Nuclear energy is the only one immediately available source does not cause global warming. In this presentation consequences and risks of global warming, as well as nuclear power comparisons will be discussed comprehensively

  12. When to stop drying fruit: Insights from hygrothermal modelling

    International Nuclear Information System (INIS)

    Defraeye, Thijs

    2017-01-01

    Highlights: • Partial dehydration reduces energy consumption and processing time and improves product quality. • This study gives a quantitative insight in when fruit drying should be stopped. • Decrease in dryer residence time of 2%, 24% and 70% are found for different stopping criteria. - Abstract: Stopping the drying process prior to complete dehydration reduces energy consumption and processing time but can also improve product quality. Using hygrothermal simulations, different stopping criteria are evaluated, which are based on the final water activity and residual moisture content in the fruit. Their impact on drying time and moisture redistribution kinetics inside fruit is quantified. One of the variants leads to a significant reduction in residence time in the dryer (24%), compared to full dehydration. For this variant, drying is stopped when the average moisture content in the sample reaches the value corresponding to an equilibrium water activity of 60% in the sample, as determined from the sorption isotherm. At the same time, this variant does not induce problems with fruit spoilage, as a sufficiently low water activity is reached after moisture redistribution during relaxation in the ambient environment. In addition, the relation of the drying time to the drying air temperature was quantified for all stopping criteria, as well as the impact of the humidity of the ambient environment in which the dried fruits are placed afterwards. This study gives a better quantitative insight in when fruit drying should be stopped, given specific drying conditions, without having to compromise food safety.

  13. Stop search in the compressed region via semileptonic decays

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Hsin-Chia; Gao, Christina; Li, Lingfeng; Neill, Nicolás A. [Department of Physics, University of California,Davis, California 95616 (United States)

    2016-05-05

    In supersymmetric extensions of the Standard Model, the superpartners of the top quark (stops) play the crucial role in addressing the naturalness problem. For direct pair-production of stops with each stop decaying into a top quark plus the lightest neutralino, the standard stop searches have difficulty finding the stop for a compressed spectrum where the mass difference between the stop and the lightest neutralino is close to the top quark mass, because the events look too similar to the large tt̄ background. With an additional hard ISR jet, the two neutralinos from the stop decays are boosted in the opposite direction and they can give rise to some missing transverse energy. This may be used to distinguish the stop decays from the backgrounds. In this paper we study the semileptonic decay of such signal events for the compressed mass spectrum. Although the neutrino from the W decay also produces some missing transverse energy, its momentum can be reconstructed from the kinematic assumptions and mass-shell conditions. It can then be subtracted from the total missing transverse momentum to obtain the neutralino contribution. Because it suffers from less backgrounds, we show that the semileptonic decay channel has a better discovery reach than the fully hadronic decay channel along the compressed line m{sub t̃}−m{sub χ̃}≈m{sub t}. With 300 fb{sup −1}, the 13 TeV LHC can discover the stop up to 500 GeV, covering the most natural parameter space region.

  14. Conservation of systems during prolonged stops

    International Nuclear Information System (INIS)

    Fernandez Movellan, J.

    2014-01-01

    The objective of the project is to define the configuration, maintenance, and testing/operation of the different systems required in operation to power, in a way that is ensure adequate conservation allowing you to return to the safe operation of the Central with the reliability of such systems. (Author)

  15. ELectron stopping of heavy ions in a matter

    International Nuclear Information System (INIS)

    Akhiezer, I.A.; Davydov, L.N.

    1978-01-01

    The theory of heavy ion stopping by electrons in solids is analyzed with an aim to establish which physical mechanisms are of importance at different ion velocity values v. The theory is presented for deep inelastic collisions taking the main part in stopping at v > Zsub(1)sup(1/3) v 0 (z 1 is the atomic number of the ion, v 0 is the Bohr velocity). Elastic scattering (relative to the incident ion) are investigated. It is shown that the contribution from these processes to the stopping cross-section is predominant at Zsub(1)sup(1/3) v 0 > v > Zsub(1)sup(2/3) v 0

  16. A Phonemic and Acoustic Analysis of Hindko Oral Stops

    Directory of Open Access Journals (Sweden)

    Haroon Ur RASHID

    2014-12-01

    Full Text Available Hindko is an Indo-Aryan language that is mainly spoken in Khyber Pukhtoonkhaw province of Pakistan. This work aims to identify the oral stops of Hindko and determine the intrinsic acoustic cues for them. The phonemic analysis is done with the help of minimal pairs and phoneme distribution in contrastive environments which reveals that Hindko has twelve oral stops with three way series. The acoustic analysis of these segments shows that intrinsically voice onset time (VOT, closure duration and burst are reliable and distinguishing cues of stops in Hindko.

  17. When the engineering has to stop

    International Nuclear Information System (INIS)

    Baker, J.W.

    1985-01-01

    The paper proposes that, in the UK, there needs to be a fundamental change in the attitudes of engineers. Engineering alone is not enough for engineers. They need to see themselves in the broader context of society as a whole. At present there is a general distrust by the general public of science and engineering, mainly because engineers have kept quiet for too long, and have been letting facts speak for themselves when they should have been explaining them. Now it is up to the engineering profession to educate the general public in terms that they can understand, in an attempt to win back wider public support. The paper includes a discussion of some aspects of the UK nuclear power programme: the choice of reactor types; reprocessing and waste disposal; Sizewell-B enquiry; public opinion on civil nuclear power; CEGB public relations. (author)

  18. Project STOP (Spectral Thermal Optimization Program)

    Science.gov (United States)

    Goldhammer, L. J.; Opjorden, R. W.; Goodelle, G. S.; Powe, J. S.

    1977-01-01

    The spectral thermal optimization of solar cell configurations for various solar panel applications is considered. The method of optimization depends upon varying the solar cell configuration's optical characteristics to minimize panel temperatures, maximize power output and decrease the power delta from beginning of life to end of life. Four areas of primary investigation are: (1) testing and evaluation of ultraviolet resistant coverslide adhesives, primarily FEP as an adhesive; (2) examination of solar cell absolute spectral response and corresponding cell manufacturing processes that affect it; (3) experimental work with solar cell manufacturing processes that vary cell reflectance (solar absorptance); and (4) experimental and theoretical studies with various coverslide filter designs, mainly a red rejection filter. The Hughes' solar array prediction program has been modified to aid in evaluating the effect of each of the above four areas on the output of a solar panel in orbit.

  19. Torness - why it should be stopped

    Energy Technology Data Exchange (ETDEWEB)

    1980-12-01

    The subject is discussed under the following headings: South of Scotland Electricity Board's plans; Torness (proposed nuclear power plant) and Craigroyston (proposed pumped storage scheme); no need for it; overcapacity; premature closures (of other SSEB plants); unemployment; not 'local' (reference to workers at Torness); safety unknown; secrecy; halt called for (on safety grounds); mad economics; increasing construction costs; nuclear is not cheaper; a robust economic case (query); AGR problems; Hinkley point incident; Hunterston incident; refuelling; Torness AGR.

  20. Optimal Locations of Bus Stops Connecting Subways near Urban Intersections

    Directory of Open Access Journals (Sweden)

    Yuan Cui

    2015-01-01

    Full Text Available Unsuitable locations of bus stops which provide feeder transportation connecting subways near urban intersections usually lead to the low efficiency of public transport and level of passenger service. A multiobjective optimization model to distribute such stop locations is proposed to attain the shortest total walk distance of passengers and minimum delay time of cars through intersections and travel time of buses. The Pareto frontier and optimal solutions for the proposed model are given by the distance-based and enumerative methods. The Xizhimen bus stop is selected to implement case studies for verifying the validity of the proposed model. The analysis of sensitivity on possible solutions is also carried out in the case studies. The results show that the proposed model is capable of optimizing the locations of bus stops connecting subways near intersections and helpful to improve the level of passengers service and operational efficiency of public transportation.

  1. Observations of NC stop nets for bottlenose dolphin takes

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — To observe the NC stop net fishery to document the entanglement of bottlenose dolphins and movement of dolphins around the nets.

  2. Kidney Dialysis: When Is It Time to Stop?

    Science.gov (United States)

    ... is it time to stop? My 82-year-old husband has been on kidney dialysis for a ... of Privacy Practices Notice of Nondiscrimination Manage Cookies Advertising Mayo Clinic is a not-for-profit organization ...

  3. Analysis of movable bus stop boarding and alighting areas.

    Science.gov (United States)

    2013-05-01

    This study explored the feasibility of using movable and reusable boarding and alighting (B&A) pads at bus stops. : Potential design alternatives in terms of materials and structural support for these pads were evaluated. The review : focused on the ...

  4. Density dependence of stopping cross sections measured in liquid ethane

    International Nuclear Information System (INIS)

    Both, G.; Krotz, R.; Lohmer, K.; Neuwirth, W.

    1983-01-01

    Electronic stopping cross sections for 7 Li projectiles (840--175 keV) have been measured with the inverted Doppler-shift attenuation method in liquid ethane (C 2 H 6 ) at two different densities. The density of the target has been varied by changing the temperature, and measurements have been performed at 0.525 g/cm 3 (199 K) and 0.362 g/cm 3 (287 K). At the higher density the stopping cross section is about 2% smaller. This result agrees with a calculation of the stopping cross section of liquid ethane, applying Lindhard's theory in the local-density approximation using a simple model of the liquid. It is also in agreement with various observations of the so-called physical-state effect, which show that the stopping cross section of the same substance is smaller in a condensed phase than in the gaseous one

  5. We Can Stop HIV One Conversation at a Time

    Centers for Disease Control (CDC) Podcasts

    As part of the We Can Stop HIV One Conversation at a Time campaign, this 30 second PSA encourages Hispanics/Latinos to talk openly about HIV and AIDS with their families, friends, partners, and communities.

  6. Stopping the Spread of Germs at Home, Work and School

    Science.gov (United States)

    ... Pandemic Other Stopping the Spread of Germs at Home, Work & School Language: English (US) Español Recommend on Facebook ... everyone from getting germs or spreading germs at home, work, or school. Clean and disinfect surfaces or objects. ...

  7. Vaccines Stop Illness | NIH MedlinePlus the Magazine

    Science.gov (United States)

    ... please turn JavaScript on. Feature: Diseases and Vaccinations Vaccines Stop Illness Past Issues / Spring 2015 Table of ... like polio and meningitis will affect their children. Vaccine Safety In light of recent questions about vaccine ...

  8. Mechanical stop mechanism for overcoming MEMS fabrication tolerances

    International Nuclear Information System (INIS)

    Hussein, Hussein; Bourbon, Gilles; Le Moal, Patrice; Lutz, Philippe; Haddab, Yassine

    2017-01-01

    A mechanical stop mechanism is developed in order to compensate MEMS fabrication tolerances in discrete positioning. The mechanical stop mechanism is designed to be implemented on SOI wafers using a common DRIE etching process. The various fabrication tolerances obtained due to the etching process are presented and discussed in the paper. The principle and design of the mechanism are then presented. Finally, experiments on microfabricated positioning prototypes show accurate steps unaffected by the fabrication tolerances. (technical note)

  9. Station Stopping of Freight Trains with Pneumatic Braking

    OpenAIRE

    Yun Bai; Baohua Mao; Tinkin Ho; Yu Feng; Shaokuan Chen

    2014-01-01

    In Chinese mainline railway, freight trains need to stop within passenger stations at times because of the delayed passenger trains. Without any decision-support system, it is very difficult for drivers to stop trains within stations with consistency in one braking action. The reasons are that braking performance of train changes with the conditions of braking equipment and the drivers’ subjective evaluations of track profiles and braking distance are vague and imprecise. This paper presents ...

  10. Motor Preparation Disrupts Proactive Control in the Stop Signal Task

    Directory of Open Access Journals (Sweden)

    Wuyi Wang

    2018-05-01

    Full Text Available In a study of the stop signal task (SST we employed Bayesian modeling to compute the estimated likelihood of stop signal or P(Stop trial by trial and identified regional processes of conflict anticipation and response slowing. A higher P(Stop is associated with prolonged go trial reaction time (goRT—a form of sequential effect—and reflects proactive control of motor response. However, some individuals do not demonstrate a sequential effect despite similar go and stop success (SS rates. We posited that motor preparation may disrupt proactive control more in certain individuals than others. Specifically, the time interval between trial and go signal onset—the fore-period (FP—varies across trials and a longer FP is associated with a higher level of motor preparation and shorter goRT. Greater motor preparatory activities may disrupt proactive control. To test this hypothesis, we compared brain activations and Granger causal connectivities of 81 adults who demonstrated a sequential effect (SEQ and 35 who did not (nSEQ. SEQ and nSEQ did not differ in regional activations to conflict anticipation, motor preparation, goRT slowing or goRT speeding. In contrast, SEQ and nSEQ demonstrated different patterns of Granger causal connectivities. P(Stop and FP activations shared reciprocal influence in SEQ but FP activities Granger caused P(Stop activities unidirectionally in nSEQ, and FP activities Granger caused goRT speeding activities in nSEQ but not SEQ. These findings support the hypothesis that motor preparation disrupts proactive control in nSEQ and provide direct neural evidence for interactive go and stop processes.

  11. Unsure When to Stop? Ask Your Semantic Neighbors

    OpenAIRE

    Gonçalves, Ivo; Silva, Sara; Fonseca, Carlos M.; Castelli, Mauro

    2017-01-01

    In iterative supervised learning algorithms it is common to reach a point in the search where no further induction seems to be possible with the available data. If the search is continued beyond this point, the risk of overfitting increases significantly. Following the recent developments in inductive semantic stochastic methods, this paper studies the feasibility of using information gathered from the semantic neighborhood to decide when to stop the search. Two semantic stopping criteria are...

  12. Good news is bad news: Leverage cycles and sudden stops

    OpenAIRE

    Akinci, Ozge; Chahrour, Ryan

    2015-01-01

    We show that a model with imperfectly forecastable changes in future productivity and an occasionally binding collateral constraint can match a set of stylized facts about “sudden stop” events. “Good” news about future productivity raises leverage during times of expansion, increasing the probability that the constraint binds, and a sudden stop occurs, in future periods. The economy exhibits a boom period in the run-up to the sudden stop, with output, consumption, and investment all above tre...

  13. Modeling Stop-and-Go Waves in Pedestrian Dynamics

    OpenAIRE

    Portz, Andrea; Seyfried, Armin

    2010-01-01

    Several spatially continuous pedestrian dynamics models have been validated against empirical data. We try to reproduce the experimental fundamental diagram (velocity versus density) with simulations. In addition to this quantitative criterion, we tried to reproduce stop-and-go waves as a qualitative criterion. Stop-and-go waves are a characteristic phenomenon for the single file movement. Only one of three investigated models satisfies both criteria.

  14. Captivated by nuclear power

    International Nuclear Information System (INIS)

    Kaageson, P.; Kjellstroem, B.

    1984-01-01

    The Swedish decision to discontinue nuclear power production is discussed. The basis of the referendum is presented. A number of cases where the decision to stop production in the year 2010 is counteracted, are described. The political and technical steps to facilitate the settlement are presented. (GB)

  15. The frequentist implications of optional stopping on Bayesian hypothesis tests.

    Science.gov (United States)

    Sanborn, Adam N; Hills, Thomas T

    2014-04-01

    Null hypothesis significance testing (NHST) is the most commonly used statistical methodology in psychology. The probability of achieving a value as extreme or more extreme than the statistic obtained from the data is evaluated, and if it is low enough, the null hypothesis is rejected. However, because common experimental practice often clashes with the assumptions underlying NHST, these calculated probabilities are often incorrect. Most commonly, experimenters use tests that assume that sample sizes are fixed in advance of data collection but then use the data to determine when to stop; in the limit, experimenters can use data monitoring to guarantee that the null hypothesis will be rejected. Bayesian hypothesis testing (BHT) provides a solution to these ills because the stopping rule used is irrelevant to the calculation of a Bayes factor. In addition, there are strong mathematical guarantees on the frequentist properties of BHT that are comforting for researchers concerned that stopping rules could influence the Bayes factors produced. Here, we show that these guaranteed bounds have limited scope and often do not apply in psychological research. Specifically, we quantitatively demonstrate the impact of optional stopping on the resulting Bayes factors in two common situations: (1) when the truth is a combination of the hypotheses, such as in a heterogeneous population, and (2) when a hypothesis is composite-taking multiple parameter values-such as the alternative hypothesis in a t-test. We found that, for these situations, while the Bayesian interpretation remains correct regardless of the stopping rule used, the choice of stopping rule can, in some situations, greatly increase the chance of experimenters finding evidence in the direction they desire. We suggest ways to control these frequentist implications of stopping rules on BHT.

  16. Gluon saturation and baryon stopping in the SPS, RHIC, and LHC energy regions

    International Nuclear Information System (INIS)

    Li Shuang; Feng Shengqin

    2012-01-01

    A new geometrical scaling method with a gluon saturation rapidity limit is proposed to study the gluon saturation feature of the central rapidity region of relativistic nuclear collisions. The net-baryon number is essentially transported by valence quarks that probe the saturation regime in the target by multiple scattering. We take advantage of the gluon saturation model with geometric scaling of the rapidity limit to investigate net baryon distributions, nuclear stopping power and gluon saturation features in the SPS and RHIC energy regions. Predictions for net baryon rapidity distributions, mean rapidity loss and gluon saturation feature in central Pb + Pb collisions at the LHC are made in this paper. (authors)

  17. Critique of one-stop siting in Washington: streamlining review without compromising effectiveness

    International Nuclear Information System (INIS)

    Granger, J.A.; Wise, K.R.

    1980-01-01

    The state of Washington adopted a one-stop power plant siting law in 1970 so that the regulatory elements could be coordinated into a single siting decision. Efficiency improves as duplications and inconsistencies disappear, but increasing lead times and higher costs persist in the state. An analysis of the legislation examines why certain statutory and regulatory provisions allow this to happen, pointing particularly at the review and approval process. Appropriate reforms include adequate funds and staff for the permit agency, early identification of issues, prehearing conferences, and explicit guidelines and standards. 114 references and footnotes

  18. Stopping times in cessation flows of Bingham plastics with slip at the wall

    Science.gov (United States)

    Philippou, Maria; Damianou, Yiolanda; Kaoullas, George; Georgiou, Georgios C.

    2012-09-01

    We solve numerically the cessation of axisymmetric Poiseuille flow of a Bingham plastic assuming that slip occurs along the wall. A power-law expression is used to relate the wall shear stress to the slip velocity. The numerical results show that the velocity becomes and remains uniform before complete cessation and that the stopping time is finite only when the exponent sBingham number and the volumetric flow rate decays exponentially. When s>1, the decay is much slower, i.e. polynomial. The asymptotic expressions for the volumetric flow rate in the case of full-slip are also derived.

  19. Nuclear power in the US

    International Nuclear Information System (INIS)

    Judson, Tim

    2018-01-01

    The Trump government promotes the further operation of aging nuclear power plants in the US by governmental support although several operators close their nuclear power plants due to economic reasons. The Trump government is also repowering the Yucca-Mountain-Project for radioactive waste disposal that was stopped by the Obama government based on geological problems in the region.

  20. Exploring the nearly degenerate stop region with sbottom decays

    Energy Technology Data Exchange (ETDEWEB)

    An, Haipeng [Walter Burke Institute for Theoretical Physics, California Institute of Technology,1200 E. California Blvd, Pasadena, CA, 91125 (United States); Gu, Jiayin [Center for Future High Energy Physics, Institute of High Energy Physics,19B YuquanLu, Chinese Academy of Sciences, Beijing, 100049 (China); DESY,Notkestraße 85, Hamburg, D-22607 (Germany); Wang, Lian-Tao [Enrico Fermi Institute, University of Chicago,5640 S Ellis Ave., Chicago, IL, 60637 (United States); Kavli Institute for Cosmological Physics, University of Chicago,5640 S Ellis Ave., Chicago, IL, 60637 (United States)

    2017-04-13

    A light stop with mass almost degenerate with the lightest neutralino has important connections with both naturalness and dark matter relic abundance. This region is also very hard to probe at colliders. In this paper, we demonstrate the potential of searching for such stop particles at the LHC from sbottom decays, focusing on two channels with final states 2ℓ+E{sub T}{sup miss} and 1b1ℓ+E{sub T}{sup miss}. We found that, if the lightest sbottom has mass around or below 1 TeV and has a significant branching ratio to decay to stop and W (b̃→t̃ W), a stop almost degenerate with neutralino can be excluded up to about 500–600 GeV at the 13 TeV LHC with 300 fb{sup −1} data. The searches we propose are complementary to other SUSY searches at the LHC and could have the best sensitivity to the stop-bino coannihilation region. Since they involve final states which have already been used in LHC searches, a reinterpretation of the search results already has sensitivity. Further optimization could deliver the full potential of these channels.

  1. Exploring the nearly degenerate stop region with sbottom decays

    Energy Technology Data Exchange (ETDEWEB)

    An, Haipeng [California Institute of Technology, Pasadena, CA (United States). Walter Burke Inst. for Theoretical Physics; Gu, Jiayin [Chinese Academy of Sciences, Beijing (China). Inst. of High Energy Physics; Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Wang, Lian-Tao [Chicago Univ., IL (United States). Enrico Fermi Inst.; Chicago Univ., IL (United States). Kavli Inst. for Cosmological Physics

    2016-11-15

    A light stop with mass almost degenerate with the lightest neutralino has important connections with both naturalness and dark matter relic abundance. This region is also very hard to probe at colliders. In this paper, we demonstrate the potential of searching for such stop particles at the LHC from sbottom decays, focusing on two channels with final states 2l+E{sup miss}{sub T} and 1b1l+E{sup miss}{sub T}. We found that, if the lightest sbottom has mass around or below 1 TeV and has a significant branching ratio to decay to stop and W (b→tW), a stop almost degenerate with neutralino can be excluded up to about 500-600 GeV at the 13 TeV LHC with 300 fb{sup -1} data. The searches we propose are complementary to other SUSY searches at the LHC and could have the best sensitivity to the stop-bino coannihilation region. Since they involve final states which have already been used in LHC searches, a reinterpretation of the search results already has sensitivity. Further optimization could deliver the full potential of these channels.

  2. Stopping time of a one-dimensional bounded quantum walk

    International Nuclear Information System (INIS)

    Luo Hao; Zhang Peng; Zhan Xiang; Xue Peng

    2016-01-01

    The stopping time of a one-dimensional bounded classical random walk (RW) is defined as the number of steps taken by a random walker to arrive at a fixed boundary for the first time. A quantum walk (QW) is a non-trivial generalization of RW, and has attracted a great deal of interest from researchers working in quantum physics and quantum information. In this paper, we develop a method to calculate the stopping time for a one-dimensional QW. Using our method, we further compare the properties of stopping time for QW and RW. We find that the mean value of the stopping time is the same for both of these problems. However, for short times, the probability for a walker performing a QW to arrive at the boundary is larger than that for a RW. This means that, although the mean stopping time of a quantum and classical walker are the same, the quantum walker has a greater probability of arriving at the boundary earlier than the classical walker. (paper)

  3. Reciprocity in the electronic stopping of slow ions in matter

    International Nuclear Information System (INIS)

    Sigmund, P.

    2008-01-01

    The principle of reciprocity, i.e., the invariance of the inelastic excitation in ion-atom collisions against interchange of projectile and target, has been applied to the electronic stopping cross section of low-velocity ions and tested empirically on ion-target combinations supported by a more or less adequate amount of experimental data. Reciprocity is well obeyed (within ∼10%) for many systems studied, and deviations exceeding ∼20% are exceptional. Systematic deviations such as gas-solid or metal-insulator differences have been looked for but not identified on the present basis. A direct consequence of reciprocity is the equivalence of Z 1 with Z 2 structure for random slowing down. This feature is reasonably well supported empirically for ion-target combinations involving carbon, nitrogen, aluminium and argon. Reciprocity may be utilized as a criterion to reject questionable experimental data. In cases where a certain stopping cross section has not been or cannot be measured, the stopping cross section for the inverted system may be available and serve as a first estimate. It is suggested to build in reciprocity as a fundamental requirement into empirical interpolation schemes directed at the stopping of low-velocity ions. Examination of the SRIM and MSTAR codes reveals cases where reciprocity is obeyed accurately, but deviations of up to a factor of two are common. In case of heavy ions such as gold, electronic stopping cross sections predicted by SRIM are asserted to be almost an order of magnitude too high. (authors)

  4. Reciprocity in the electronic stopping of slow ions in matter

    Science.gov (United States)

    Sigmund, P.

    2008-04-01

    The principle of reciprocity, i.e., the invariance of the inelastic excitation in ion-atom collisions against interchange of projectile and target, has been applied to the electronic stopping cross section of low-velocity ions and tested empirically on ion-target combinations supported by a more or less adequate amount of experimental data. Reciprocity is well obeyed (within ~10%) for many systems studied, and deviations exceeding ~20% are exceptional. Systematic deviations such as gas-solid or metal-insulator differences have been looked for but not identified on the present basis. A direct consequence of reciprocity is the equivalence of Z1 with Z2 structure for random slowing down. This feature is reasonably well supported empirically for ion-target combinations involving carbon, nitrogen, aluminium and argon. Reciprocity may be utilized as a criterion to reject questionable experimental data. In cases where a certain stopping cross section has not been or cannot be measured, the stopping cross section for the inverted system may be available and serve as a first estimate. It is suggested to build in reciprocity as a fundamental requirement into empirical interpolation schemes directed at the stopping of low-velocity ions. Examination of the SRIM and MSTAR codes reveals cases where reciprocity is obeyed accurately, but deviations of up to a factor of two are common. In case of heavy ions such as gold, electronic stopping cross sections predicted by SRIM are asserted to be almost an order of magnitude too high.

  5. Quantum–classical simulations of the electronic stopping force and charge on slow heavy channelling ions in metals

    International Nuclear Information System (INIS)

    Race, C P; Mason, D R; Foo, M H F; Foulkes, W M C; Sutton, A P; Horsfield, A P

    2013-01-01

    By simulating the passage of heavy ions along open channels in a model crystalline metal using semi-classical Ehrenfest dynamics we directly investigate the nature of non-adiabatic electronic effects. Our time-dependent tight-binding approach incorporates both an explicit quantum mechanical electronic system and an explicit representation of a set of classical ions. The coupled evolution of the ions and electrons allows us to explore phenomena that lie beyond the approximations made in classical molecular dynamics simulations and in theories of electronic stopping. We report a velocity-dependent charge-localization phenomenon not predicted by previous theoretical treatments of channelling. This charge localization can be attributed to the excitation of electrons into defect states highly localized on the channelling ion. These modes of excitation only become active when the frequency at which the channelling ion moves from interstitial point to equivalent interstitial point matches the frequency corresponding to excitations from the Fermi level into the localized states. Examining the stopping force exerted on the channelling ion by the electronic system, we find broad agreement with theories of slow ion stopping (a stopping force proportional to velocity) for a low velocity channelling ion (up to about 0.5 nm fs −1 from our calculations), and a reduction in stopping power attributable to the charge localization effect at higher velocities. By exploiting the simplicity of our electronic structure model we are able to illuminate the physics behind the excitation processes that we observe and present an intuitive picture of electronic stopping from a real-space, chemical perspective. (paper)

  6. Stopping and energy deposition of hadrons in target nuclei

    International Nuclear Information System (INIS)

    Strugalski, Z.

    1983-01-01

    In an analysis of pion-xenon nucleus collisions at 2.34-9 GeV/c momentum events are identified in which incident pions were completely stopped and deposited their energy in target nucleus. Probability of appearance of such ''stopped'' events among any-type pion-xenon collision events depends on the incident pion momentum and is: approximately 0.15 at 2.34 GeV/c, approximately 0.02 at 3.5 GeV/c, and approximately 0 at higher momenta. Formula expressing probability of appearance of the ''stopped'' events is derived. Range-energy relation in nuclear matter for pions and protons is given

  7. Ball Screw Actuator Including a Compliant Ball Screw Stop

    Science.gov (United States)

    Wingett, Paul T. (Inventor); Hanlon, Casey (Inventor)

    2017-01-01

    An actuator includes a ball nut, a ball screw, and a ball screw stop. The ball nut is adapted to receive an input torque and in response rotates and supplies a drive force. The ball screw extends through the ball nut and has a first end and a second end. The ball screw receives the drive force from the ball nut and in response selectively translates between a retract position and a extend position. The ball screw stop is mounted on the ball screw proximate the first end to translate therewith. The ball screw stop engages the ball nut when the ball screw is in the extend position, translates, with compliance, a predetermined distance toward the first end upon engaging the ball nut, and prevents further rotation of the ball screw upon translating the predetermined distance.

  8. Ball Screw Actuator Including an Axial Soft Stop

    Science.gov (United States)

    Wingett, Paul T. (Inventor); Forrest, Steven Talbert (Inventor); Abel, Steve (Inventor); Woessner, George (Inventor); Hanlon, Casey (Inventor)

    2016-01-01

    An actuator includes an actuator housing, a ball screw, and an axial soft stop assembly. The ball screw extends through the actuator housing and has a first end and a second end. The ball screw is coupled to receive a drive force and is configured, upon receipt of the drive force, to selectively move in a retract direction and an extend direction. The axial soft stop assembly is disposed within the actuator housing. The axial soft stop assembly is configured to be selectively engaged by the ball screw and, upon being engaged thereby, to translate, with compliance, a predetermined distance in the extend direction, and to prevent further movement of the ball screw upon translating the predetermined distance.

  9. Why do People Stop Playing On-Line Games?

    DEFF Research Database (Denmark)

    Sudzina, Frantisek; Razmerita, Liana

    2012-01-01

    The recent initial public offering of shares of Zynga, probably the most important on-line game provider, drew interest of potential investors but also of general public to their business model. What the most interested people learned so far is that if Zynga had not changed their accounting...... practice, they would be in red numbers for several months already. This is most likely caused by people stopping to play their games. This paper provides an estimate of what proportion of people, who played on-line games, already stopped playing them. Additionally, it analyzed the reasons why people...... stopped playing on-line games. It also compares Facebook and other on-line games....

  10. Fricative-stop coarticulation: acoustic and perceptual evidence.

    Science.gov (United States)

    Repp, B H; Mann, V A

    1982-06-01

    Eight native speakers of American English each produced ten tokens of all possible CV, FCV, and VFCV utterances with V = [a] or [u], F = [s] or [integral of], and C = [t] or [k]. Acoustic analysis showed that the formant transition onsets following the stop consonant release were systematically influenced by the preceding fricative, although there were large individual differences. In particular, F3 and F4 tended to be higher following [s] than following [integral of]. The coarticulatory effects were equally large in FCV (e.g.,/sta/) and VFCV (e.g.,/asda/) utterances; that is, they were not reduced when a syllable boundary intervened between fricative and stop. In a parallel perceptual study, the CV portions of these utterances (with release bursts removed to provoke errors) were presented to listeners for identification of the stop consonant. The pattern of place-of-articulation confusions, too, revealed coarticulatory effects due to the excised fricative context.

  11. Companion classroom activities for "stop faking it!" force and motion

    CERN Document Server

    Robertson, William C

    2011-01-01

    Never has it been so easy for educators to learn to teach physical science with confidence. Award-winning author Bill Robertson launched his bestselling Stop Faking It! series in 2002 with Force and Motion--offering elementary and middle school teachers a jargon-free way to learn the background for teaching physical science with confidence. Combining easy-to-understand if irreverent explanations and quirky diagrams, Stop Faking It! Force and Motion helped thousands of teachers, parents, and homeschoolers conquer topics from Newton s laws to the physics of space travel. Now Companion Classroom Activities for Stop Faking It! Force and Motion proves an ideal supplement to the original book or a valuable resource of its own. The hands-on activities and highly readable explanations allow students to first investigate concepts, then discuss learned concepts, and finally apply the concepts to everyday situations. Robertson's wit and humor are sure to keep students and teachers entertained while they tackle topics ...

  12. 49 CFR 392.22 - Emergency signals; stopped commercial motor vehicles.

    Science.gov (United States)

    2010-10-01

    ... REGULATIONS DRIVING OF COMMERCIAL MOTOR VEHICLES Stopped Commercial Motor Vehicles § 392.22 Emergency signals; stopped commercial motor vehicles. (a) Hazard warning signal flashers. Whenever a commercial motor vehicle... than necessary traffic stops, the driver of the stopped commercial motor vehicle shall immediately...

  13. Can I Stop Myself From Having a Wet Dream? (For Teens)

    Science.gov (United States)

    ... Can I Stop Myself From Having a Wet Dream? KidsHealth / For Teens / Can I Stop Myself From Having a Wet Dream? Print Can I stop myself from having a wet dream? – Tom* You really can't stop wet dreams, ...

  14. One-stop endoscopic hernia surgery: efficient and satisfactory.

    Science.gov (United States)

    Voorbrood, C E H; Burgmans, J P J; Clevers, G J; Davids, P H P; Verleisdonk, E J M M; Schouten, N; van Dalen, T

    2015-06-01

    One-stop surgery offers patients diagnostic work-up and subsequent surgical treatment on the same day. In the present study, patient satisfaction and efficiency from an institutional perspective were evaluated in patients who were referred for one-stop endoscopic inguinal hernia repair. In a high-volume inguinal hernia clinic, all consecutive patients referred for one-stop surgical treatment, were registered prospectively. An instructed secretary screened patients for eligibility for the one-stop option when the appointment was made. Totally extraperitoneal hernia repair under general anaesthesia was the preferred operative technique. Patient's satisfaction, successful day surgery and institutional efficiency were evaluated. Between January 2010 and January 2012 a total of 349 patients (17 % of all patients in the hernia clinic) were referred for one-stop hernia repair. Mean age was 47.5 years and 96.3 % were males. Three hundred thirty-six patients underwent hernia surgery on the same day (96.3 %). In thirteen patients (3.7 %) no operative repair was done on the day of presentation due to an incorrect diagnosis (n = 7), a watchful waiting policy for asymptomatic hernia (n = 3), rescheduling due to a large scrotal hernia, and there were two "no shows". Following hernia repair 97 % of the patients were discharged on the same day, while ten patients required hospitalization. Based on the questionnaires the main satisfaction score among patients was 9.0 (8.89-9.17 95 % CI) on a scale ranging from 0 to 10. One-stop hernia surgery is feasible and satisfactory from an institutional as well as from a patient's perspective.

  15. A Conceptual Approach for Optimising Bus Stop Spacing

    Science.gov (United States)

    Johar, Amita; Jain, S. S.; Garg, P. k.

    2017-06-01

    An efficient public transportation system is essential of any country. The growth, development and shape of the urban areas are mainly due to availability of good transportation (Shah et al. in Inst Town Plan India J 5(3):50-59, 1). In developing countries, like India, travel by local bus in a city is very common. The accidents, congestion, pollution and appropriate location of bus stops are the major problems arising in metropolitan cities. Among all the metropolitan cities in India, Delhi has highest percentage of growth of population and vehicles. Therefore, it is important to adopt efficient and effective ways to improve mobility in different metropolitan cities in order to overcome the problem and to reduce the number of private vehicles on the road. The primary objective of this paper is to present a methodology for developing a model for optimum bus stop spacing (OBSS). It describes the evaluation of existing urban bus route, data collection, development of model for optimizing urban bus route and application of model. In this work, the bus passenger generalized cost method is used to optimize the spacing between bus stops. For the development of model, a computer program is required to be written. The applicability of the model has been evaluated by taking the data of urban bus route of Delhi Transport Corporation (DTC) in Excel sheet in first phase. Later on, it is proposed to develop a programming in C++ language. The developed model is expected to be useful to transport planner for rational design of the spacing of bus stops to save travel time and to generalize operating cost. After analysis it is found that spacing between the bus stop comes out to be between 250 and 500 m. The Proposed Spacing of bus stops is done considering the points that they don't come nearer to metro/rail station, entry or exit of flyover and near traffic signal.

  16. Light stops and fine-tuning in MSSM

    Energy Technology Data Exchange (ETDEWEB)

    Cici, Ali; Kirca, Zerrin; Uen, Cem Salih [Uludag Univ., Department of Physics, Bursa (Turkey)

    2018-01-15

    We discuss the fine-tuning issue within the MSSM framework. Following the idea that the fine-tuning can measure effects of some missing mechanism, we impose non-universal gaugino masses at the GUT scale, and explore the low scale implications. We realize that the fine-tuning parametrized with Δ{sub EW} can be as low as zero. We consider the stop mass with a special importance and focus on the mass scales as m{sub t} ≤ 700 GeV, which are excluded by the current experiments when the stop decays into a neutralino along with a top quark or a chargino along with a bottom quark. We find that the stop mass can be as low as about 250 GeV with Δ{sub EW} ∝ 50. We find that the solutions in this region can be excluded only up to 60% when stop decays into a neutralino-top quark, and 50% when it decays into a chargino-b quark. Setting 65% CL to be potential exclusion and 95% to be pure exclusion limit such solutions will be tested in near future experiments, which are conducted with higher luminosity. In addition to stop, the region with low fine-tuning and light stops predicts masses for the other supersymmetric particles such as m{sub b} >or similar 700 GeV, m{sub τ} >or similar 1 TeV, m{sub χ{sub 1}{sup {sub ±}}} >or similar 120 GeV. The details for the mass scales and decay rates are also provided by tables of benchmark points. (orig.)

  17. Light stops and fine-tuning in MSSM

    Science.gov (United States)

    Çiçi, Ali; Kırca, Zerrin; Ün, Cem Salih

    2018-01-01

    We discuss the fine-tuning issue within the MSSM framework. Following the idea that the fine-tuning can measure effects of some missing mechanism, we impose non-universal gaugino masses at the GUT scale, and explore the low scale implications. We realize that the fine-tuning parametrized with Δ _{EW} can be as low as zero. We consider the stop mass with a special importance and focus on the mass scales as m_{\\tilde{t}} ≤ 700 GeV, which are excluded by the current experiments when the stop decays into a neutralino along with a top quark or a chargino along with a bottom quark. We find that the stop mass can be as low as about 250 GeV with Δ _{EW} ˜ 50. We find that the solutions in this region can be exluded only up to 60% when stop decays into a neutralino-top quark, and 50% when it decays into a chargino-b quark. Setting 65% CL to be potential exclusion and 95% to be pure exclusion limit such solutions will be tested in near future experiments, which are conducted with higher luminosity. In addition to stop, the region with low fine-tuning and light stops predicts masses for the other supersymmetric particles such as m_{\\tilde{b}} ≳ 700 GeV, m_{\\tilde{τ }} ≳ 1 TeV, m_{\\tilde{χ }1^{± }} ≳ 120 GeV. The details for the mass scales and decay rates are also provided by tables of benchmark points.

  18. International Symposium of Scientists for Nuclear test Stopping

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

    Problems discussed at International Symposium of Scientists for Nuclear Test Stopping in July 1986 in Moscow were considered. Scientists discussed complex of possible measures directed at strengthening of peace supporting mechanism, spoke in support of prohibition of all nuclear weapon tests. Necessity of measures preventing the weapon delivery to space, construction of the regime of using cosmic equipment exclusively for peace was noted. Attention was paid to the problem of control for test stopping (by means of sattelites and seismic methods), cooperation establishment between the USSR Academy of Sciences and the Council for the protection of the USA Natural Resources

  19. Anatomy of maximal stop mixing in the MSSM

    International Nuclear Information System (INIS)

    Bruemmer, Felix; Kraml, Sabine; Kulkarni, Suchita

    2012-05-01

    A Standard Model-like Higgs near 125 GeV in the MSSM requires multi-TeV stop masses, or a near-maximal contribution to its mass from stop mixing. We investigate the maximal mixing scenario, and in particular its prospects for being realized it in potentially realistic GUT models. We work out constraints on the possible GUT-scale soft terms, which we compare with what can be obtained from some well-known mechanisms of SUSY breaking mediation. Finally, we analyze two promising scenarios in detail, namely gaugino mediation and gravity mediation with non-universal Higgs masses.

  20. Anatomy of maximal stop mixing in the MSSM

    Energy Technology Data Exchange (ETDEWEB)

    Bruemmer, Felix [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Kraml, Sabine; Kulkarni, Suchita [CNRS/IN2P3, INPG, Grenoble (France). Laboratoire de Physique Subatomique et de Cosmologie

    2012-05-15

    A Standard Model-like Higgs near 125 GeV in the MSSM requires multi-TeV stop masses, or a near-maximal contribution to its mass from stop mixing. We investigate the maximal mixing scenario, and in particular its prospects for being realized it in potentially realistic GUT models. We work out constraints on the possible GUT-scale soft terms, which we compare with what can be obtained from some well-known mechanisms of SUSY breaking mediation. Finally, we analyze two promising scenarios in detail, namely gaugino mediation and gravity mediation with non-universal Higgs masses.

  1. Maintenance cost savings - snubber elimination with limit stops

    International Nuclear Information System (INIS)

    Monette, P.; Baltus, R.; Cloud, R.L.

    1995-01-01

    ''Active'' snubbers can be replaced with ''passive'' Limit Stops using two separate strategies. One is a straightforward piping re-analysis to optimize the number of dynamics supports and replace remaining snubbers with Limit Stops. A second approach is to take implicit advantage of the margins afforded by the ASME Code Case N-411 damping ratios and simply replace snubbers one-for-one with no re-analysis. Both methods result in major maintenance cost savings and both have been received favorably by the USNRC (United States Nuclear Regulatory Commission). Approaches to maintenance cost reduction using these strategies are discussed in this paper. (Author). 11 refs., 4 figs

  2. Maintenance cost savings - snubber elimination with limit stops

    International Nuclear Information System (INIS)

    Cloud, R.L.; Taylor, W.H.

    1993-01-01

    'Active' snubbers can be replaced with 'passive' Limit Stops using two separate strategies. One is a straightforward piping re-analysis to optimize the number of dynamic supports and replace remaining snubbers with Limit Stops. A second approach is to take implicit advantage of the margins afforded by the ASME Code Case N-411 reduced damping ratios and simply replace snubbers one-for-one with no re-analysis. Both methods result in major maintenance cost savings and both have been discussed with the NRC. Approaches to maintenance cost reduction using these strategies are discussed in this paper

  3. The Stop Transmission of Polio Data Management (STOP DM) assignment and its role in polio eradication and immunization data improvement in Africa

    OpenAIRE

    Benke, Amalia; Williams, Alford Joseph; MacNeil, Adam

    2017-01-01

    The availability and use of high quality immunization and surveillance data are crucial for monitoring all components of the Global Polio Eradication Program (GPEI). The Stop Transmission of Polio (STOP) program was initiated in 1999 to train and mobilize human resources to provide technical support to polio endemic and at-risk countries and in 2002 the STOP data management (STOP DM) deployment was created to provide capacity development in the area of data management for immunization and sur...

  4. P.R. and advertising campaign 'Let us stop smoking together'

    International Nuclear Information System (INIS)

    Kacena, Michal

    1999-01-01

    CEZ is the main supplier of electricity in the Czech republic. (72% of production from coal, 22% of people agree to continue; 25% of production from nuclear, 55% of people agree to continue, but, it is much more politically sensitive). In 1998 a huge six-year ecological programme ended. The CEZ Communication targets are: to point the succesful finishing of the ecological program and its good results, to iprove the company image, to change the public opinion on pollution issues. Communication problems are: how to make the technical topic interesting and understandable to the general public, and how to avoid a criticism and contra-productivity of the advertising? The solution proposed are: to give the information a social 'added value'- our power plants are going to stop smoking. We know it is not easy, so that we want to motivate and help you - try it yourself together with us. 'Let us stop smoking together!'; to combine the advertising and P.R. activities. Now CEZ can continue with the communication about its activities and plans on the new level. The inspiration for the communication about nuclear power plants: 'NPPs do not smoke at a. Let us think about it together!'

  5. Stimulus-response mappings shape inhibition processes: a combined EEG-fMRI study of contextual stopping.

    Directory of Open Access Journals (Sweden)

    Christina F Lavallee

    Full Text Available Humans are rarely faced with one simple task, but are typically confronted with complex stimulus constellations and varying stimulus-relevance in a given situation. Through modifying the prototypical stop-signal task and by combined recording and analysis of electroencephalography (EEG and functional magnetic resonance imaging (fMRI, we studied the effects of stimulus relevance for the generation of a response or its inhibition. Stimulus response mappings were modified by contextual cues, indicating which of two different stimuli following a go stimulus was relevant for stopping. Overall, response inhibition, that is comparing successful stopping to a stop-signal against go-signal related processes, was associated with increased activity in right inferior and left midfrontal regions, as well as increased EEG delta and theta power; however, stimulus-response conditions in which the most infrequent stop-signal was relevant for inhibition, were associated with decreased activity in regions typically involved in response inhibition, as well as decreased activity in the delta and theta bands as compared to conditions wherein the relevant stop-signal frequency was higher. Behaviorally, this (aforementioned condition, which demanded inhibition only from the most infrequent stimulus, was also associated with reduced reaction times and lower error rates. This pattern of results does not align with typical stimulus frequency-driven findings and suggests interplay between task relevance and stimulus frequency of the stop-signal. Moreover, with a multimodal EEG-fMRI analysis, we demonstrated significant parameterization for response inhibition with delta, theta and beta time-frequency values, which may be interpreted as reflecting conflict monitoring, evaluative and/or motor processes as suggested by previous work (Huster et al., 2013; Aron, 2011. Further multimodal results suggest a possible neurophysiological and behavioral benefit under conditions

  6. Is one-stop surgery for carpal tunnel syndrome safe?

    DEFF Research Database (Denmark)

    Jørgensen, Louise Møller; Piil, Karin; Bashir, Asma

    2017-01-01

    OBJECTIVES: The aim of this study was to evaluate one-stop surgery (OSS) for carpal tunnel syndrome (CTS) regarding symptom relief and patient satisfaction. OSS in our setting means only one visit to the hospital for surgery and no hospital appointments for preassessment or follow-up. We hypothes...

  7. What You Can Do to Stop the Flu

    Science.gov (United States)

    ... of this page please turn Javascript on. Feature: Flu What You Can Do to Stop the Flu Past Issues / Fall 2009 Table of Contents To ... Health and Human Services: http://flu.gov NIH Flu Research to Results Scientists at the National Institute ...

  8. Inferring Stop-Locations from WiFi.

    Directory of Open Access Journals (Sweden)

    David Kofoed Wind

    Full Text Available Human mobility patterns are inherently complex. In terms of understanding these patterns, the process of converting raw data into series of stop-locations and transitions is an important first step which greatly reduces the volume of data, thus simplifying the subsequent analyses. Previous research into the mobility of individuals has focused on inferring 'stop locations' (places of stationarity from GPS or CDR data, or on detection of state (static/active. In this paper we bridge the gap between the two approaches: we introduce methods for detecting both mobility state and stop-locations. In addition, our methods are based exclusively on WiFi data. We study two months of WiFi data collected every two minutes by a smartphone, and infer stop-locations in the form of labelled time-intervals. For this purpose, we investigate two algorithms, both of which scale to large datasets: a greedy approach to select the most important routers and one which uses a density-based clustering algorithm to detect router fingerprints. We validate our results using participants' GPS data as well as ground truth data collected during a two month period.

  9. Detector for recoil nuclei stopping in the spark chamber gas

    International Nuclear Information System (INIS)

    Aleksanyan, A.S.; Asatiani, T.L.; Ivanov, V.I.; Mkrtchyan, G.G.; Pikhtelev, R.N.

    1974-01-01

    A detector consisting of the combination of a drift and a wide gap spark chambers and designed to detect recoil nuclei stopping in the spark chamber gas is described. It is shown, that by using an appropriate discrimination the detector allows to detect reliably the recoil nuclei in the presence of intensive electron and γ-quanta beams

  10. On a rational stopping rule for facilities location algorithms

    DEFF Research Database (Denmark)

    Juel, Henrik

    1984-01-01

    In the multifacility location problem, a number of new facilities are to be located so as to minimize a sum of weighted distances. Love and Yeong (1981) developed a lower bound on the optimal value for use in deciding when to stop an iterative solution procedure. The authors develop a stronger...

  11. Stopping particles in the Mont Blanc spark chamber telescopes

    Energy Technology Data Exchange (ETDEWEB)

    Bergamasco, L; Bilokon, H; Piazzoli, B E; Mannocchi, G; Picchi, P [Consiglio Nazionale delle Ricerche, Turin (Italy). Lab. di Cosmo-Geofisica; Turin Univ. (Italy). Ist. di Fisica Generale)

    1982-02-01

    We present the final results on the ratio of stopping to traversing muons as measured by two spark chamber telescopes in the Mont Blanc Station, Italy, at 4300 hg/cm/sup 2/. The experimental results are in agreement with the theoretical values within the limits of the error.

  12. 32 CFR 636.30 - Stopping, standing and parking.

    Science.gov (United States)

    2010-07-01

    ... ENFORCEMENT AND CRIMINAL INVESTIGATIONS MOTOR VEHICLE TRAFFIC SUPERVISION (SPECIFIC INSTALLATIONS) Fort... which obstructs traffic. (g) No driver will stand or park a vehicle, whether occupied or not, except...) Within 20 feet upon the approach to any flashing signal, a stop sign, yield sign, or traffic control...

  13. Inferring Stop-Locations from WiFi

    DEFF Research Database (Denmark)

    Wind, David Kofoed; Sapiezynski, Piotr; Furman, Magdalena Anna

    2016-01-01

    methods are based exclusively on WiFi data. We study two months of WiFi data collected every two minutes by a smartphone, and infer stop-locations in the form of labelled time-intervals. For this purpose, we investigate two algorithms, both of which scale to large datasets: a greedy approach to select...

  14. 14 CFR 25.109 - Accelerate-stop distance.

    Science.gov (United States)

    2010-01-01

    ... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Flight Performance § 25.109 Accelerate-stop distance. (a...) The maximum tire-to-ground wet runway braking coefficient of friction is defined as: ER18FE98.004 Where— Tire Pressure=maximum airplane operating tire pressure (psi); μt/gMAX=maximum tire-to-ground...

  15. Annihilation of antiprotons stopped in liquid hydrogen and deuterium

    International Nuclear Information System (INIS)

    Dalkarov, O.D.; Kerbikov, B.O.; Markushin, V.E.

    1976-01-01

    Detailed analysis is given of stopping antiproton annihilation in liquid hydrogen and deuterium. Connection between capture schedule and properties of bound states in nucleon-antinucleon system is established. The theoretical predictions are compared with experimental data which appeared in 1971-75

  16. Assessing One-stop-shop Best Practices for South African ...

    African Journals Online (AJOL)

    One stop shop (OSS) models are an investment process that came about to create a centralised place for the voluminous documentation required in international trade between companies. Bureaucracy has proven to be a major barrier to the development of international trade, particularly in African countries that still lag ...

  17. Reasons for Starting and Stopping Electronic Cigarette Use

    Directory of Open Access Journals (Sweden)

    Jessica K. Pepper

    2014-10-01

    Full Text Available The aim of our study was to explore reasons for starting and then stopping electronic cigarette (e-cigarette use. Among a national sample of 3878 U.S. adults who reported ever trying e-cigarettes, the most common reasons for trying were curiosity (53%; because a friend or family member used, gave, or offered e-cigarettes (34%; and quitting or reducing smoking (30%. Nearly two-thirds (65% of people who started using e-cigarettes later stopped using them. Discontinuation was more common among those whose main reason for trying was not goal-oriented (e.g., curiosity than goal-oriented (e.g., quitting smoking (81% vs. 45%, p < 0.001. The most common reasons for stopping e-cigarette use were that respondents were just experimenting (49%, using e-cigarettes did not feel like smoking cigarettes (15%, and users did not like the taste (14%. Our results suggest there are two categories of e-cigarette users: those who try for goal-oriented reasons and typically continue using and those who try for non-goal-oriented reasons and then typically stop using. Research should distinguish e-cigarette experimenters from motivated users whose decisions to discontinue relate to the utility or experience of use. Depending on whether e-cigarettes prove to be effective smoking cessation tools or whether they deter cessation, public health programs may need distinct strategies to reach and influence different types of users.

  18. Reasons for starting and stopping electronic cigarette use.

    Science.gov (United States)

    Pepper, Jessica K; Ribisl, Kurt M; Emery, Sherry L; Brewer, Noel T

    2014-10-03

    The aim of our study was to explore reasons for starting and then stopping electronic cigarette (e-cigarette) use. Among a national sample of 3878 U.S. adults who reported ever trying e-cigarettes, the most common reasons for trying were curiosity (53%); because a friend or family member used, gave, or offered e-cigarettes (34%); and quitting or reducing smoking (30%). Nearly two-thirds (65%) of people who started using e-cigarettes later stopped using them. Discontinuation was more common among those whose main reason for trying was not goal-oriented (e.g., curiosity) than goal-oriented (e.g., quitting smoking) (81% vs. 45%, p reasons for stopping e-cigarette use were that respondents were just experimenting (49%), using e-cigarettes did not feel like smoking cigarettes (15%), and users did not like the taste (14%). Our results suggest there are two categories of e-cigarette users: those who try for goal-oriented reasons and typically continue using and those who try for non-goal-oriented reasons and then typically stop using. Research should distinguish e-cigarette experimenters from motivated users whose decisions to discontinue relate to the utility or experience of use. Depending on whether e-cigarettes prove to be effective smoking cessation tools or whether they deter cessation, public health programs may need distinct strategies to reach and influence different types of users.

  19. Drinking and driving behavior at stop signs and red lights.

    Science.gov (United States)

    Wan, Jingyan; Wu, Changxu; Zhang, Yiqi; Houston, Rebecca J; Chen, Chang Wen; Chanawangsa, Panya

    2017-07-01

    Alcohol is one of the principal risk factors for motor vehicle crashes. One factor that contributes to vehicle crashes is noncompliance with stop signs and red lights. The present experiment investigated the effects of alcohol and drinking patterns on driving behavior at stop signs and red lights. 28 participants participated in drinking and simulated driving sessions during which they received a moderate dose of alcohol (0.08% BAC) or a placebo. Simulated driving tasks measured participants' driving performance at stop signs and red lights in response to each dose. Results suggested that alcohol impaired the driver control of speed and direction and prolonged their simple and complex reaction time, which were exhibited by impaired speed and lateral control, longer reaction time when the lights turned yellow, and lower deceleration towards stop signs and red lights. Visual degradation may also occur under alcohol intake. It was also suggested that alcohol impaired non-binge drinkers more severely. To be specific, higher acceleration was observed in impaired non-binge drinkers. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. "STOP the Violence": FCCLA Program Tackles School Issue

    Science.gov (United States)

    Journal of Family and Consumer Sciences, 2004

    2004-01-01

    "STOP the Violence--Students Taking on Prevention" is a program designed to involve students and address school violence at its core from the peer-to- peer perspective. Developed by members of the Family, Career and Community Leaders of America (FCCLA), the program empowers young persons to recognize, report, and reduce the potential for youth…

  1. A Connection between Singular Stochastic Control and Optimal Stopping

    International Nuclear Information System (INIS)

    Espen Benth, Fred; Reikvam, Kristin

    2003-01-01

    We show that the value function of a singular stochastic control problem is equal to the integral of the value function of an associated optimal stopping problem. The connection is proved for a general class of diffusions using the method of viscosity solutions

  2. Negative Thought Stopping. A Key to Performance Enhancement.

    Science.gov (United States)

    Ziegler, Susan G.

    1987-01-01

    The effects of mental training on skill acquisition and performance is currently emphasized in the study of sport psychology and motor learning. This article provides the teacher and coach with general guidelines for understanding and incorporating negative thought stopping training into athletic programs. (MT)

  3. Stop the Tears of Drug and Alcohol Abuse

    Science.gov (United States)

    Shimon, Jane; Gibson, Terry-Ann; Spear, Caile

    2009-01-01

    Objectives: By participating in this Stop the Tears teaching strategy, students will be able to: (1) analyze how alcohol and drug abuse could affect their lives as well as the lives of their friends and family and, (2) create a media message, such as a poster, pamphlet, poem, or song, in which alcohol and drug prevention is advocated specific to…

  4. Impact-parameter-dependent electronic stopping of swift ions

    NARCIS (Netherlands)

    Schinner, A.; Sigmund, P.

    2010-01-01

    A computational scheme has been developed to estimate the mean electronic energy loss of an incident swift ion on an atomic target as a function of the impact parameter between the moving nuclei. The theoretical basis is binary stopping theory. In order to extract impact-parameter dependencies it

  5. 49 CFR 236.516 - Power supply.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Power supply. 236.516 Section 236.516..., Train Control and Cab Signal Systems Standards § 236.516 Power supply. Automatic cab signal, train stop, or train control device hereafter installed shall operate from a separate or isolated power supply...

  6. Stashing the stops in multijet events at the LHC

    Science.gov (United States)

    Diglio, Sara; Feligioni, Lorenzo; Moultaka, Gilbert

    2017-09-01

    While the presence of a light stop is increasingly disfavored by the experimental limits set on R-parity conserving scenarios, the naturalness of supersymmetry could still be safely concealed in the more challenging final states predicted by the existence of non-null R-parity violating couplings. Although R-parity violating signatures are extensively looked for at the Large Hadron Collider, these searches mostly assume 100% branching ratios for the direct decays of supersymmetric particles into Standard Model ones. In this paper we scrutinize the implications of relaxing this assumption by focusing on one motivated scenario where the lightest stop is heavier than a chargino and a neutralino. Considering a class of R-parity baryon number violating couplings, we show on general grounds that while the direct decay of the stop into Standard Model particles is dominant for large values of these couplings, smaller values give rise, instead, to the dominance of a plethora of longer decay chains and richer final states that have been so far barely analyzed at the LHC, thus weakening the impact of the present experimental stop mass limits. We characterize the case for R-parity baryon number violating couplings in the 10-7-10-1 range, in two different benchmark points scenarios within the model-independent setting of the low-energy phenomenological Minimal Supersymmetric Standard Model. We identify the different relevant experimental signatures from stop pair production and decays, estimate the corresponding proton-proton cross sections at √{s }=14 TeV and discuss signal versus background issues.

  7. Coherent resonance stop bands in alternating gradient beam transport

    Science.gov (United States)

    Ito, K.; Okamoto, H.; Tokashiki, Y.; Fukushima, K.

    2017-06-01

    An extensive experimental study is performed to confirm fundamental resonance bands of an intense hadron beam propagating through an alternating gradient linear transport channel. The present work focuses on the most common lattice geometry called "FODO" or "doublet" that consists of two quadrupoles of opposite polarities. The tabletop ion-trap system "S-POD" (Simulator of Particle Orbit Dynamics) developed at Hiroshima University is employed to clarify the parameter-dependence of coherent beam instability. S-POD can provide a non-neutral plasma physically equivalent to a charged-particle beam in a periodic focusing potential. In contrast with conventional experimental approaches relying on large-scale machines, it is straightforward in S-POD to control the doublet geometry characterized by the quadrupole filling factor and drift-space ratio. We verify that the resonance feature does not essentially change depending on these geometric factors. A few clear stop bands of low-order resonances always appear in the same pattern as previously found with the sinusoidal focusing model. All stop bands become widened and shift to the higher-tune side as the beam density is increased. In the space-charge-dominated regime, the most dangerous stop band is located at the bare betatron phase advance slightly above 90 degrees. Experimental data from S-POD suggest that this severe resonance is driven mainly by the linear self-field potential rather than by nonlinear external imperfections and, therefore, unavoidable at high beam density. The instability of the third-order coherent mode generates relatively weak but noticeable stop bands near the phase advances of 60 and 120 degrees. The latter sextupole stop band is considerably enhanced by lattice imperfections. In a strongly asymmetric focusing channel, extra attention may have to be paid to some coupling resonance lines induced by the Coulomb potential. Our interpretations of experimental data are supported by theoretical

  8. Perspectives of nuclear power plants

    International Nuclear Information System (INIS)

    Vajda, Gy.

    2001-01-01

    In several countries the construction of nuclear power plants has been stopped, and in some counties several plants have been decommissioned or are planned to. Therefore, the question arises: have nuclear power plants any future? According to the author, the question should be reformulated: can mankind survive without nuclear power? To examine this challenge, the global power demand and its trends are analyzed. According to the results, traditional energy sources cannot be adequate to supply power. Therefore, a reconsideration of nuclear power should be imminent. The economic, environmental attractions are discussed as opposite to the lack of social support. (R.P.)

  9. Using the Stop Transmission of Polio (STOP) Program to Develop a South Sudan Expanded Program on Immunization Workforce.

    Science.gov (United States)

    Tchoualeu, Dieula D; Hercules, Margaret A; Mbabazi, William B; Kirbak, Anthony L; Usman, Abdulmumini; Bizuneh, Ketema; Sandhu, Hardeep S

    2017-07-01

    In 2009, the international Stop Transmission of Polio (STOP) program began supporting the Global Polio Eradication Initiative in the Republic of South Sudan to address shortages of human resources and strengthen acute flaccid paralysis surveillance. Workforce capacity support is provided to the South Sudan Expanded Program on Immunization by STOP volunteers, implementing partners, and non-governmental organizations. In 2013, the Polio Technical Advisory Group recommended that South Sudan transition key technical support from external partners to national staff as part of the Polio Eradication and Endgame Strategic Plan, 2013-2018. To assist in this transition, the South Sudan Expanded Program on Immunization human resources development project was launched in 2015. This 3-year project aims to build national workforce capacity as a legacy of the STOP program by training 56 South Sudanese at national and state levels with the intent that participants would become Ministry of Health staff on their successful completion of the project. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America.

  10. The Stop Transmission of Polio Data Management (STOP DM) assignment and its role in polio eradication and immunization data improvement in Africa.

    Science.gov (United States)

    Benke, Amalia; Williams, Alford Joseph; MacNeil, Adam

    2017-01-01

    The availability and use of high quality immunization and surveillance data are crucial for monitoring all components of the Global Polio Eradication Program (GPEI). The Stop Transmission of Polio (STOP) program was initiated in 1999 to train and mobilize human resources to provide technical support to polio endemic and at-risk countries and in 2002 the STOP data management (STOP DM) deployment was created to provide capacity development in the area of data management for immunization and surveillance data for these countries. Since 2002, Africa has received the majority of support from the STOP DM program, with almost 80% of assignments being placed in African countries. The STOP DM program has played a valuable role in improving the quality and use of data for the GPEI and has increasingly supported other immunization program data needs. In this report we provide an overview of the history, current status, and future of the STOP DM program, with a specific focus on the African continent.

  11. Introduction to Stopping Time in Stochastic Finance Theory. Part II

    Directory of Open Access Journals (Sweden)

    Jaeger Peter

    2017-12-01

    Full Text Available We start proceeding with the stopping time theory in discrete time with the help of the Mizar system [1], [4]. We prove, that the expression for two stopping times k1 and k2 not always implies a stopping time (k1 + k2 (see Theorem 6 in this paper. If you want to get a stopping time, you have to cut the function e.g. (k1 + k2 ⋂ T (see [2, p. 283 Remark 6.14]. Next we introduce the stopping time in continuous time. We are focused on the intervals [0, r] where r ∈ ℝ. We prove, that for I = [0, r] or I = [0,+∞[ the set {A ⋂ I : A ∈ Borel-Sets} is a σ-algebra of I (see Definition 6 in this paper, and more general given in [3, p.12 1.8e]. The interval I can be considered as a timeline from now to some point in the future. This set is necessary to define our next lemma. We prove the existence of the σ-algebra of the τ -past, where τ is a stopping time (see Definition 11 in this paper and [6, p.187, Definition 9.19]. If τ1 and τ2 are stopping times with τ1 is smaller or equal than τ2 we can prove, that the σ-algebra of the τ1-past is a subset of the σ-algebra of the τ2-past (see Theorem 9 in this paper and [6, p.187 Lemma 9.21]. Suppose, that you want to use Lemma 9.21 with some events, that never occur, see as a comparison the paper [5] and the example for ST(1={+∞} in the Summary. We don’t have the element +1 in our above-mentioned time intervals [0, r[ and [0,+1[. This is only possible if we construct a new σ-algebra on ℝ {−∞,+∞}. This construction is similar to the Borel-Sets and we call this σ-algebra extended Borel sets (see Definition 13 in this paper and [3, p. 21]. It can be proved, that {+∞} is an Element of extended Borel sets (see Theorem 21 in this paper. Now we use the interval [0,+∞] as a basis. We construct a σ-algebra on [0,+∞] similar to the book ([3, p. 12 18e], see Definition 18 in this paper, and call it extended Borel subsets. We prove for stopping times with this given σ-algebra, that

  12. Energy policy and nuclear power. Expectations of the power industry

    International Nuclear Information System (INIS)

    Harig, H.D.

    1995-01-01

    In the opinion of the power industry, using nuclear power in Germany is a responsible attitude, while opting out of nuclear power is not. Electricity utilities will build new nuclear power plants only if the structural economic and ecological advantages of nuclear power are preserved and can be exploited in Germany. The power industry will assume responsibility for new complex, capital-intensive nuclear plants only if a broad societal consensus about this policy can be reached in this country. The power industry expects that the present squandering of nuclear power resources in Germany will be stopped. The power industry is prepared to contribute to finding a speedy consensus in energy policy, which would leave open all decisions which must not be taken today, and which would not constrain the freedom of decision of coming generations. The electricity utilities remain committed proponents of nuclear power. However, what they sell to their customers is electricity, not nuclear power. (orig.) [de

  13. Continuing versus Stopping Prestroke Antihypertensive Therapy in Acute Intracerebral Hemorrhage

    DEFF Research Database (Denmark)

    Krishnan, Kailash; Scutt, Polly; Woodhouse, Lisa

    2016-01-01

    BACKGROUND AND PURPOSE: More than 50% of patients with acute intracerebral hemorrhage (ICH) are taking antihypertensive drugs before ictus. Although antihypertensive therapy should be given long term for secondary prevention, whether to continue or stop such treatment during the acute phase of ICH...... remains unclear, a question that was addressed in the Efficacy of Nitric Oxide in Stroke (ENOS) trial. METHODS: ENOS was an international multicenter, prospective, randomized, blinded endpoint trial. Among 629 patients with ICH and systolic blood pressure between 140 and 220 mmHg, 246 patients who were...... taking antihypertensive drugs were assigned to continue (n = 119) or to stop (n = 127) taking drugs temporarily for 7 days. The primary outcome was the modified Rankin Score at 90 days. Secondary outcomes included death, length of stay in hospital, discharge destination, activities of daily living, mood...

  14. Discrete Analysis of Portfolio Selection with Optimal Stopping Time

    Directory of Open Access Journals (Sweden)

    Jianfeng Liang

    2009-01-01

    Full Text Available Most of the investments in practice are carried out without certain horizons. There are many factors to drive investment to a stop. In this paper, we consider a portfolio selection policy with market-related stopping time. Particularly, we assume that the investor exits the market once his wealth reaches a given investment target or falls below a bankruptcy threshold. Our objective is to minimize the expected time when the investment target is obtained, at the same time, we guarantee the probability that bankruptcy happens is no larger than a given level. We formulate the problem as a mix integer linear programming model and make analysis of the model by using a numerical example.

  15. Stopped-pipe wind instruments: Acoustics of the panpipes

    Science.gov (United States)

    Fletcher, N. H.

    2005-01-01

    Stopped-pipe jet-excited musical instruments are known in many cultures, those best-known today being the panpipes or syrinx of Eastern Europe and of the Peruvian Andes. Although the playing style differs, in each case the instrument consists of a set of graduated bamboo pipes excited by blowing across the open tops. Details of the excitation aerodynamics warrant examination, particularly as the higher notes contain amplitudes of the even harmonics approaching those of the odd harmonics expected from a stopped pipe. Analysis shows that the jet offset is controlled by the fluid dynamics of the jet, and is such that appreciable even-harmonic excitation is generated. The theory is largely confirmed by measurements on a player. .

  16. Ball Screw Actuator Including a Stop with an Integral Guide

    Science.gov (United States)

    Wingett, Paul T. (Inventor); Perek, John (Inventor); Geck, Kellan (Inventor)

    2015-01-01

    An actuator includes a housing assembly, a ball nut, a ball screw, and a ball screw stop. The ball nut is rotationally mounted in the housing assembly, is adapted to receive an input torque, and is configured, upon receipt thereof, to rotate and supply a drive force. The ball screw is mounted within the housing assembly and extends through the ball nut. The ball screw has a first end and a second end, and is coupled to receive the drive force from the ball nut. The ball screw is configured, upon receipt of the drive force, to selectively translate between a stow position and a deploy position. The ball screw stop is mounted on the ball screw to translate therewith and is configured to at selectively engage the housing assembly while the ball screw is translating, and engage the ball nut when the ball screw is in the deploy position.

  17. Improved atomic data for electron-transport predictions by the codes TIGER and TIGERP: II. Electron stopping and range data

    International Nuclear Information System (INIS)

    Peek, J.M.; Halbleib, J.A.

    1983-04-01

    The electron stopping and range data now used in the TIGER and TIGERP electron-transport codes are extracted and compared with other data for these processes. At the smallest collision energies treated by these codes, E approx. 1 keV, the stopping-power is estimated to be accurate for small-Z targets, to be about 25 percent too small for Z near 36 and to be a factor of three too small for Z > 79. These errors decrease with increasing E and the largest error for any target is roughly 20 percent for E = 10 keV. The closely related continuous-slowing-down range is estimated, at 1 keV, to be about 25 percent too small for small-Z targets and a factor of 2 too large for large-Z targets. The electron-transport problem of reflection from planer surfaces is re-investigated with improved stopping-power data. The effects of this change for the examples considered were about the size of the statistical uncertainties in the calculation, 1 to 2 percent

  18. Why alite stops hydrating below 80% relative humidity

    International Nuclear Information System (INIS)

    Flatt, Robert J.; Scherer, George W.; Bullard, Jeffrey W.

    2011-01-01

    It has been observed that the hydration of cement paste stops when the relative humidity drops below about 80%. A thermodynamic analysis shows that the capillary pressure exerted at that RH shifts the solubility of tricalcium silicate, so that it is in equilibrium with water. This is a reflection of the chemical shrinkage in this system: according to Le Chatelier's principle, since the volume of the products is less than that of the reactants, a negative (capillary) pressure opposes the reaction.

  19. We Can Stop HIV One Conversation at a Time

    Centers for Disease Control (CDC) Podcasts

    2014-08-28

    As part of the We Can Stop HIV One Conversation at a Time campaign, this 30 second PSA encourages Hispanics/Latinos to talk openly about HIV and AIDS with their families, friends, partners, and communities.  Created: 8/28/2014 by National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention (NCHHSTP).   Date Released: 8/28/2014.

  20. City Under Siege: Narrating Mumbai Through NonStop Capture

    OpenAIRE

    Yasmin Ibrahim

    2009-01-01

    When Mumbai became the target of terror in the 26/11 attack in 2008, the events in that city, like other tragic global events in recent years, were narrated through new media platforms. The increasing convergence of technologies and mobile telephony enabled new forms of gaze and the ability to bear witness through these new media technologies. The non-stop capture of events through recording equipment embedded in mobile phones and their connectivity to the World Wide Web constructed Mumbai th...

  1. Stopping Mass Killings in Africa: Genocide, Airpower and Intervention

    Science.gov (United States)

    2008-07-01

    University Press Maxwell Air Force Base, Alabama July 2008 20081027249 Muir S. Fairchild Research Information Center Cataloging Data Stopping mass...commander, who controlled the Habr Gedir subclan, and that of All Mahdi Mohamed, a wealthy Mogadishu hotelier and self- proclaimed interim president of...carry a big stick." Yet both the force com- mander and the AETF commander should think hard before employing that stick. A wide array of actors is

  2. How to Stop the Bear: Strategy of Small States

    Science.gov (United States)

    2010-12-01

    stressing the role of international law, and abstentionism from security alliance” (George J. Stein, 1990, p. 4). At the same time, the Dutch were reluctant...NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS Approved for public release; distribution is unlimited HOW TO STOP THE BEAR...estimated to average 1 hour per response, including the time for reviewing instruction, searching existing data sources, gathering and maintaining

  3. One-stop shopping in Africa's minerals supermarket

    International Nuclear Information System (INIS)

    Spira, J.

    1980-01-01

    Johannesburg in South Africa is one of the minerals capitals of the world, providing a one-stop shopping supermarket for the most sought-after strategic minerals. Total annual mineral sales grew from R1563 million in 1970 to R6876 million in 1978. For 1979 the figure exceeded R9700 million. Production, trade and marketing of gold, coal, platinum, uranium, diamonds, iron ore, copper, antimony, mineral sands, asbestos and vanadium are shortly discussed

  4. Analysing passenger arrivals rates and waiting time at bus stops

    OpenAIRE

    Kaparias, I.; Rossetti, C.; Trozzi, V.

    2015-01-01

    The present study investigates the rather under-explored topic of passenger waiting times at public transport facilities. Using data collected from part of London’s bus network by means of physical counts, measurements and observations, and complemented by on-site passenger interviews, the waiting behaviour is analysed for a number of bus stops served by different numbers of lines. The analysis employs a wide range of statistical methods and tools, and concentrates on three aspects: passenger...

  5. Should we stop thinking about inhibition? Searching for individual and age differences in inhibition ability.

    Science.gov (United States)

    Rey-Mermet, Alodie; Gade, Miriam; Oberauer, Klaus

    2018-04-01

    Inhibition is often conceptualized as a unitary construct reflecting the ability to ignore and suppress irrelevant information. At the same time, it has been subdivided into inhibition of prepotent responses (i.e., the ability to stop dominant responses) and resistance to distracter interference (i.e., the ability to ignore distracting information). The present study investigated the unity and diversity of inhibition as a psychometric construct, and tested the hypothesis of an inhibition deficit in older age. We measured inhibition in young and old adults with 11 established laboratory tasks: antisaccade, stop-signal, color Stroop, number Stroop, arrow flanker, letter flanker, Simon, global-local, positive and negative compatibility tasks, and n-2 repetition costs in task switching. In both age groups, the inhibition measures from individual tasks had good reliabilities, but correlated only weakly among each other. Structural equation modeling identified a 2-factor model with factors for inhibition of prepotent responses and resistance to distracter interference. Older adults scored worse in the inhibition of prepotent response, but better in the resistance to distracter interference. However, the model had low explanatory power. Together, these findings call into question inhibition as a psychometric construct and the hypothesis of an inhibition deficit in older age. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  6. Proton stopping using a full conserving dielectric function in plasmas at any degeneracy

    International Nuclear Information System (INIS)

    Barriga-Carrasco, Manuel D.

    2010-01-01

    In this work, we present a dielectric function including the three conservation laws (density, momentum and energy) when we take into account electron-electron collisions in a plasma at any degeneracy. This full conserving dielectric function (FCDF) reproduces the random phase approximation (RPA) and Mermin ones, which confirms this outcome. The FCDF is applied to the determination of the proton stopping power. Differences among diverse dielectric functions in the proton stopping calculation are minimal if the plasma electron collision frequency is not high enough. These discrepancies can rise up to 2% between RPA values and the FCDF ones, and to 8% between the Mermin ones and FCDF ones. The similarity between RPA and FCDF results is not surprising, as all conservation laws are also considered in RPA dielectric function. Even for plasmas with low collision frequencies, those discrepancies follow the same behavior as for plasmas with higher frequencies. Then, discrepancies do not depend on the plasma degeneracy but essentially do on the value of the plasma collision frequency.

  7. Scattering and stopping of swift diatomic molecules under Coulomb explosion

    International Nuclear Information System (INIS)

    Sigmund, P.

    1992-01-01

    The scattering and stopping of the fragments of a fast diatomic molecule under Coulomb explosion has been analysed theoretically. The central assumption in the scheme is the dominance of Coulomb explosion, while electronic stopping (including wake forces) and elastic scattering are treated as perturbations. Charge exchange has been neglected. Coulomb images of penetration phenomena are heavily distorted. For small penetrated layer thicknesses, images appear contracted in the direction of the molecular axis, and expanded perpendicular to it. This distortion is described quantitatively by a linear transformation. General expressions have been derived for the effect of continuous and stochastic forces on the distribution of fragment velocities from Coulomb explosion (the ''ring pattern''). Moreover, relations have been found that allow to scale velocity distributions valid in the absence of Coulomb explosion into distributions allowing for Coulomb explosion. Applications concern the shift in ring pattern due to electronic stopping, the lateral broadening due to multiple scattering, and the effect of zero-point motion on the Coulomb image of a molecule. (orig.)

  8. Scattering and stopping of swift diatomic molecules under Coulomb explosion

    International Nuclear Information System (INIS)

    Sigmund, P.

    1991-01-01

    The scattering and stopping of the fragments of a fast diatomic molecule under Coulomb explosion has been analyzed theoretically. The central assumption in the scheme is the dominance of Coulomb explosion, while electronic stopping (including wake forces) and elastic scattering are treated as perturbations. Charge exchange has been neglected. Coulomb images of penetration phenomena are heavily distorted. For small penetrated layer thicknesses, images appear contracted in the direction of the molecular axis, and expanded perpendicular to it. This distortion is described quantitatively by a linear transformation. General expressions have been derived for the effect of continuous and stochastic forces on the distribution of fragment velocities from Coulomb explosion (the ''ring pattern''). Moreover, relations have been found that allow to scale velocity distributions valid in the absence of Coulomb explosion into distributions allowing for Coulomb explosion. Applications concern the shift in ring pattern due to electronic stopping, the lateral broadening due to multiple scattering and the effect of zero-point motion on the Coulomb image of a molecule. 14 refs., 5 figs

  9. Correlated stopping, proton clusters and higher order proton cumulants

    Energy Technology Data Exchange (ETDEWEB)

    Bzdak, Adam [AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, Krakow (Poland); Koch, Volker [Lawrence Berkeley National Laboratory, Nuclear Science Division, Berkeley, CA (United States); Skokov, Vladimir [RIKEN/BNL, Brookhaven National Laboratory, Upton, NY (United States)

    2017-05-15

    We investigate possible effects of correlations between stopped nucleons on higher order proton cumulants at low energy heavy-ion collisions. We find that fluctuations of the number of wounded nucleons N{sub part} lead to rather nontrivial dependence of the correlations on the centrality; however, this effect is too small to explain the large and positive four-proton correlations found in the preliminary data collected by the STAR collaboration at √(s) = 7.7 GeV. We further demonstrate that, by taking into account additional proton clustering, we are able to qualitatively reproduce the preliminary experimental data. We speculate that this clustering may originate either from collective/multi-collision stopping which is expected to be effective at lower energies or from a possible first-order phase transition, or from (attractive) final state interactions. To test these ideas we propose to measure a mixed multi-particle correlation between stopped protons and a produced particle (e.g. pion, antiproton). (orig.)

  10. When can immunotherapy for insect sting allergy be stopped?

    Science.gov (United States)

    Müller, Ulrich R; Ring, Johannes

    2015-01-01

    Stings by Hymenoptera (honey bees, vespids, ants) can cause systemic allergic reactions (SARs). Venom immunotherapy (VIT) is highly effective and reduces an allergic patient's risk of a recurrent SAR to less than 5-20%. The risk of a recurrent SAR to a re-sting decreases the longer VIT is continued. The recommended duration of VIT is at least 3 to 5 years. Risk factors for recurrent SARs to a sting after stopping VIT have been identified and discussed: Recommendations concerning stopping VIT: For patients without any of the identified risk factors, VIT should be continued for 5 rather than 3 years. In patients with definite risk factors, a longer duration of VIT has to be discussed before stopping it. In mast cell disorders, VIT for life is recommended. Because of the residual risk of SARs after VIT, all patients are advised to carry an epinephrine autoinjector indefinitely and to continue to take measures to avoid Hymenoptera stings. Copyright © 2015 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

  11. Stop and Fricative Devoicing in European Portuguese, Italian and German.

    Science.gov (United States)

    Pape, Daniel; Jesus, Luis M T

    2015-06-01

    This paper describes a cross-linguistic production study of devoicing for European Portuguese (EP), Italian, and German. We recorded all stops and fricatives in four vowel contexts and two word positions. We computed the devoicing of the time-varying patterns throughout the stop and fricative duration. Our results show that regarding devoicing behaviour, EP is more similar to German than Italian. While Italian shows almost no devoicing of all phonologically voiced consonants, both EP and German show strong and consistent devoicing through the entire consonant. Differences in consonant position showed no effect for EP and Italian, but were significantly different for German. The height of the vowel context had an effect for German and EP. For EP, we showed that a more posterior place of articulation and low vowel context lead to significantly more devoicing. However, in contrast to German, we could not find an influence of consonant position on devoicing. The high devoicing for all phonologically voiced stops and fricatives and the vowel context influence are a surprising new result. With respect to voicing maintenance, EP is more like German than other Romance languages.

  12. Pilot survey of subway and bus stop noise levels.

    Science.gov (United States)

    Gershon, Robyn R M; Neitzel, Richard; Barrera, Marissa A; Akram, Muhammad

    2006-09-01

    Excessive noise exposure is a serious global urban health problem, adversely affecting millions of people. One often cited source of urban noise is mass transit, particularly subway systems. As a first step in determining risk within this context, we recently conducted an environmental survey of noise levels of the New York City transit system. Over 90 noise measurements were made using a sound level meter. Average and maximum noise levels were measured on subway platforms, and maximum levels were measured inside subway cars and at several bus stops for comparison purposes. The average noise level measured on the subway platforms was 86 +/- 4 dBA (decibel-A weighting). Maximum levels of 106, 112, and 89 dBA were measured on subway platforms, inside subway cars, and at bus stops, respectively. These results indicate that noise levels in subway and bus stop environments have the potential to exceed recommended exposure guidelines from the World Health Organization (WHO) and U.S. Environmental Protection Agency (EPA), given sufficient exposure duration. Risk reduction strategies following the standard hierarchy of control measures should be applied, where feasible, to reduce subway noise exposure.

  13. Adaptive weak approximation of reflected and stopped diffusions

    KAUST Repository

    Bayer, Christian

    2010-01-01

    We study the weak approximation problem of diffusions, which are reflected at a subset of the boundary of a domain and stopped at the remaining boundary. First, we derive an error representation for the projected Euler method of Costantini, Pacchiarotti and Sartoretto [Costantini et al., SIAM J. Appl. Math., 58(1):73-102, 1998], based on which we introduce two new algorithms. The first one uses a correction term from the representation in order to obtain a higher order of convergence, but the computation of the correction term is, in general, not feasible in dimensions d > 1. The second algorithm is adaptive in the sense of Moon, Szepessy, Tempone and Zouraris [Moon et al., Stoch. Anal. Appl., 23:511-558, 2005], using stochastic refinement of the time grid based on a computable error expansion derived from the representation. Regarding the stopped diffusion, it is based in the adaptive algorithm for purely stopped diffusions presented in Dzougoutov, Moon, von Schwerin, Szepessy and Tempone [Dzougoutov et al., Lect. Notes Comput. Sci. Eng., 44, 59-88, 2005]. We give numerical examples underlining the theoretical results. © de Gruyter 2010.

  14. Maintenance management during long-term stop of JRR-3

    International Nuclear Information System (INIS)

    Matsui, Yutaka; Suwa, Masayuki; Wada, Shigeru

    2016-01-01

    JRR-3 has been continuing its stop state for more than 5 years as of FY2015 after stopping the use operation of the reactor in November 2010. Different responses are required in the maintenance management for operation resumption, compared with those in normal operation. This paper introduces part of the maintenance managements that are performed during long-term stop. The water qualities of primary coolant and secondary coolant are controlled by measuring pH and conductivity, and the prevention of crevice corrosion of equipment is performed. In the management of pumps for coolant circulation, vibration measurement is performed to confirm that there are no signs of abnormality. As the management of the core structure, the bend measurement of beryllium reflector is performed to confirm that there is no hindrance to operation resumption, and the visual inspection of high burnup fuel elements is performed to confirm that abnormality has not occurred. As for the management of monitoring equipment, the equipment required in shutdown period is subjected to calibration work, and the equipment required in operation period is subjected to soundness check based on the results of cooling system operation. As the functional maintenance of the cooling system, cooling system operating test and 10-day continuous operation of the cooling system are monthly performed to confirm the soundness of equipment. In addition, the competence maintenance and capacity improvement of operators are performed through the cooling system operation and reactor simulator training. (A.O.)

  15. Mathematical modeling for optimizing skip-stop rail transit operation strategy using genetic algorithm.

    Science.gov (United States)

    2012-03-01

    "With skip-stop rail transit operation, transit agencies can reduce their operating costs and fleet size, : and passengers can experience reduced in-transit travel times without extra track and technological : improvement. However, since skip-stop op...

  16. Torness: proposed nuclear power station

    International Nuclear Information System (INIS)

    Anon.

    1979-01-01

    The need for and desirability of nuclear power, and in particular the proposed nuclear power station at Torness in Scotland, are questioned. Questions are asked, and answered, on the following topics: position, appearance and cost of the proposed Torness plant, and whether necessary; present availability of electricity, and forecast of future needs, in Scotland; energy conservation and alternative energy sources; radiation hazards from nuclear power stations (outside, inside, and in case of an accident); transport of spent fuel from Torness to Windscale; radioactive waste management; possibility of terrorists making a bomb with radioactive fuel from a nuclear power station; cost of electricity from nuclear power; how to stop Torness. (U.K.)

  17. Shelter from the Storm: Optimizing Distribution of Bus Stop Shelters in Los Angeles

    OpenAIRE

    Law, Philip; Taylor, Brian D.

    2010-01-01

    The functions of bus stop shelters and factors affecting their placement at stops in transit systems are analyzed. Drawing on information from a variety of sources, current shelter placement policy in Los Angeles was found to be guided principally by the revenue-generating potential of shelter advertisements, secondarily by political concerns over geographic equity, and only peripherally on the basis of bus stop use. Using data on shelter and stop locations, boardings, and headways, a methodo...

  18. On NonAsymptotic Optimal Stopping Criteria in Monte Carlo Simulations

    KAUST Repository

    Bayer, Christian; Hoel, Hakon; von Schwerin, Erik; Tempone, Raul

    2014-01-01

    We consider the setting of estimating the mean of a random variable by a sequential stopping rule Monte Carlo (MC) method. The performance of a typical second moment based sequential stopping rule MC method is shown to be unreliable in such settings both by numerical examples and through analysis. By analysis and approximations, we construct a higher moment based stopping rule which is shown in numerical examples to perform more reliably and only slightly less efficiently than the second moment based stopping rule.

  19. 49 CFR 236.335 - Dogs, stops and trunnions of mechanical locking.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Dogs, stops and trunnions of mechanical locking..., AND APPLIANCES Interlocking Rules and Instructions § 236.335 Dogs, stops and trunnions of mechanical locking. Driving pieces, dogs, stops and trunnions shall be rigidly secured to locking bars. Swing dogs...

  20. Overriding actions in Parkinson’s disease : Impaired stopping and changing of motor responses

    NARCIS (Netherlands)

    van den Wildenberg, W.P.M.; Ridderinkhof, K.R.; van Wouwe, N.C.; Neimat, J.S.; Bashore, T.R.; Wylie, S.A.

    2017-01-01

    We administered a stop-change paradigm, an extended version of the stop task that requires (a) stopping an ongoing motor response and (b) changing to an alternative (change) response. Performance of a group of patients diagnosed with Parkinson's disease (PD) and taking dopaminergic medication was

  1. A Bayesian approach for estimating the probability of trigger failures in the stop-signal paradigm

    NARCIS (Netherlands)

    Matzke, D.; Love, J.; Heathcote, A.

    Response inhibition is frequently investigated using the stop-signal paradigm, where participants perform a two-choice response time task that is occasionally interrupted by a stop signal instructing them to withhold their response. Stop-signal performance is formalized as a race between a go and a

  2. Mr. Trump: How I learned to stop worrying and love the patient-aggressor.

    Science.gov (United States)

    Coren, Sidney

    2018-05-01

    This paper offers an integration of social issues, psychoanalytic theory, and analytic experience in the treatment of a patient whose political values and identifications differed significantly from my own. Our political leanings facilitated a dynamic tension of difference, power, and aggression that mirrored how each of us felt in relation to the current social-political milieu. In particular, the sadomasochistic dynamics on display in the treatment offered me a unique way of understanding my relationship with my patient and opened new ways of understanding the political present. In the end, I learned to stop worrying about getting rid of anger, aggression, and splitting, and instead to embrace what these feelings and behaviors can tell me as a therapist, and what they can inform for my patients about the nature of relationality, identity, and difference. © 2018 Wiley Periodicals, Inc.

  3. The extraction of "2"2"9Th"3"+ from a buffer-gas stopping cell

    International Nuclear Information System (INIS)

    Wense, L. von der; Seiferle, B.; Laatiaoui, M.; Thirolf, P.G.

    2016-01-01

    In the whole landscape of atomic nuclei, "2"2"9Th is currently the only known nucleus which could allow for the development of a nuclear-based frequency standard, as it possesses an isomeric state of just 7.6 eV energy above the ground state. The 3+ charge state is of special importance in this context, as Th"3"+ allows for a simple laser-cooling scheme. Here we emphasize the direct extraction of triply-charged "2"2"9Th from a buffer-gas stopping cell. This finding will not only simplify any future approach of "2"2"9Th ion cooling, but is also used for thorium-beam purification and in this way provides a powerful tool for the direct identification of the "2"2"9Th isomer to ground state nuclear transition.

  4. Human haptic perception is interrupted by explorative stops of milliseconds

    Directory of Open Access Journals (Sweden)

    Martin eGrunwald

    2014-04-01

    Full Text Available Introduction: The explorative scanning movements of the hands have been compared to those of the eyes. The visual process is known to be composed of alternating phases of saccadic eye movements and fixation pauses. Descriptive results suggest that during the haptic exploration of objects short movement pauses occur as well. The goal of the present study was to detect these explorative stops (ES during one-handed and two-handed haptic explorations of various objects and patterns, and to measure their duration. Additionally, the associations between the following variables were analyzed: a between mean exploration time and duration of ES, b between certain stimulus features and ES frequency, and c the duration of ES during the course of exploration. Methods: Five different experiments were used. The first two experiments were classical recognition tasks of unknown haptic stimuli (A and of common objects (B. In experiment C space-position information of angle legs had to be perceived and reproduced. For experiments D and E the PHANToM haptic device was used for the exploration of virtual (D and real (E sunken reliefs. Results: In each experiment we observed explorative stops of different average durations. For experiment A: 329.50 ms, experiment B: 67.47 ms, experiment C: 189.92 ms, experiment D: 186.17 ms and experiment E: 140.02 ms. Significant correlations were observed between exploration time and the duration of the ES. Also, ES occurred more frequently, but not exclusively, at defined stimulus features like corners, curves and the endpoints of lines. However, explorative stops do not occur every time a stimulus feature is explored. Conclusions: We assume that ES are a general aspect of human haptic exploration processes. We have tried to interpret the occurrence and duration of ES with respect to the Hypotheses-Rebuild-Model and the Limited Capacity Control System theory.

  5. Nuclear power for beginners

    International Nuclear Information System (INIS)

    Croall, S.; Sempler, K.

    1979-01-01

    Witty, critically, and with expert knowledge, 'Atomic power for beginners' describes the development of nuclear power for military purposes and its 'peaceful uses' against the will of the population. Atomic power, the civil baby of the bomb is not only a danger to our lives - it is enemy to all life as all hard technologies are on which economic systems preoccupied with growth put their hopes. Therefore, 'Atomic power for beginners' does not stop at nuclear engineering but proceeds to investigate its consequences, nationally and with a view to the Third World. And since the consequences are so fatal and it is not enough to say no to nuclear power, it gives some thoughts to a better future - with soft technology and alternative production. (orig.) 891 HP/orig. 892 MKO [de

  6. Capture and transfer of stopped pions in alcohols

    International Nuclear Information System (INIS)

    Harston, M.R.; Armstrong, D.S.; Measday, D.F.; Stanislaus, S.; Weber, P.; Horvath, D.

    1990-02-01

    The pion charge exchange probability in hydrogen for stopped π - has been measured for a series of alcohols. The relative atomic capture probabilities for hydrogen in different chemical environments as well as for the other molecular constituents were extracted from the data using a phenomenological approach. The results allow the prediction of the charge exchange probability in other molecules of similar chemical structure. The charge exchange probability in deuterated methanols was measured and compared to the prediction of our model. A comprehensive picture is obtained if pion transfer from hydrogen to deuterium is included

  7. Equipment for a 'non-stop' water infusion system

    Energy Technology Data Exchange (ETDEWEB)

    Deprez, J C

    1978-01-01

    This paper gives a definition of the non-stop infusion system (technique employed during the winning operation to prevent the emission of coal-dust). The system works at low-output and reduced pressure level; delivery and control is continuous. Explains the principles behind the MECANELEC flow regulator and the SCHLUMBERGER device to monitor correct operation. Describes a SCHLUMBERGER unit used in the Houilleres de Blanzy as well as a combined MECANELEC-SCHLUMBERGER installation in service at HBNPC. This combination allows water infusion to be carried out as required by the conditions. Possibility of introducing necessary improvements (such as a device to prevent leakage) is discussed.

  8. Stop staring facial modeling and animation done right

    CERN Document Server

    Osipa, Jason

    2010-01-01

    The de facto official source on facial animation—now updated!. If you want to do character facial modeling and animation at the high levels achieved in today's films and games, Stop Staring: Facial Modeling and Animation Done Right, Third Edition , is for you. While thoroughly covering the basics such as squash and stretch, lip syncs, and much more, this new edition has been thoroughly updated to capture the very newest professional design techniques, as well as changes in software, including using Python to automate tasks.: Shows you how to create facial animation for movies, games, and more;

  9. Effect of passenger position on fear of danger experienced during sudden bus stops.

    Science.gov (United States)

    Aoki, Takeo; Uetake, Teruo; Shimoda, Masahiro

    2009-06-01

    The purpose of this study was to identify the effect of bus passengers' positions on their fear of danger when a bus stopped suddenly. A temporary bus running course with one bus stop was set up on the campus of the Tokyo University of Agriculture and Technology (TUAT). The bus ran the course 14 times with the bus stopping twice during the course, once at the bus stop and again just after re-starting from the bus stop. The driver was asked to brake more strongly than usual when stopping. Sixteen students (15 males and 1 female) between the ages of 18 and 21 years participated. In turn, all participants were asked to take 14 different postures in the bus. Participants were also asked to report their level of fear on a rating scale each time the bus stopped. The study showed that (1) passengers' fear of danger at the first sudden stop was typically higher than that at the second stop, (2) standing passengers who held hand straps experienced more fear than those who held fixed safety devices, (3) bus passengers sitting on the centre of the rear seat had a great risk of injury if the bus stopped suddenly, and (4) when passengers faced the window and stood transversely with respect to from the moving direction of the bus and the bus stopped suddenly, passengers' fear of danger was affected by the side of the bus on which they stood as well as which hand they used to grasp a safety device.

  10. Development of an automated vehicle stop system for cardiac emergencies

    Directory of Open Access Journals (Sweden)

    Tung T. Nguyen

    2017-06-01

    Full Text Available This paper describes the concept and configuration of a novel automated safety vehicle stop system, and a future prospect of the study. Intrinsic sudden death may cause traffic accident since such accidents sometimes involve not only the driver but also other traffic users such as passengers and pedestrians. Cardiovascular disease (CVD is considered as a serious driving risk factor. The pain and others effects of cardiac events degrade driver’s performance, and CVD causes ischemia brought by the CVD induces incapacity of driving. In the automated safety vehicle stop system, which our research group has developed, steer-sensors collects bio-signals and a camera captures the driver’s posture to monitor driver’s incapability. When the driver loses his or her driving capability, the system takes over the maneuver of the vehicle and automatically drives to a safety spot by observing the traffic environment. An emergency scenario was used to demonstrate the system verifying its potential.

  11. How to stop tobacco use? Tobacco user′s perspective

    Directory of Open Access Journals (Sweden)

    Siddharth Sarkar

    2013-01-01

    Full Text Available Objectives: To explore the tobacco-dependent subject′s perspectives of what measures are likely to work for tobacco cessation. Materials and Methods: Nicotine-dependent male subjects attending a tertiary level de-addiction center in North India were recruited. Demographic and clinical data was recorded. Open-ended questions were asked to know user′s perspective about the measures by which tobacco use can be effectively stopped in the country. The subjects were allowed as many responses as they desired. Results: A total of 46 subjects were recruited. The median age of the sample was 35 years, with median duration of tobacco use being 12 years. All subjects were males, and most were married, employed, and had urban residence. Supply reducing measures were the most commonly reported to stop tobacco (67.4% of subjects followed by people quitting tobacco use by themselves (19.6% and raising awareness through media (13.1%. Conclusion: This pilot study reflects the perspectives of tobacco users for the measures likely to be effective in tobacco cessation. Evaluating the effect of implementation of individual policies may help focusing towards measures that yield greatest benefits.

  12. Particulate air pollution and vascular reactivity: the bus stop study.

    Science.gov (United States)

    Dales, Robert; Liu, Ling; Szyszkowicz, Mietek; Dalipaj, Mary; Willey, Jeff; Kulka, Ryan; Ruddy, Terrence D

    2007-11-01

    Particulate air pollution is associated with cardiovascular morbidity but mechanisms are not well understood. We tested the effects on vascular reactivity of exposure to fine particulates matter mass (PM(2.5)), number of particles bus stops. Flow-mediated vasodilation (FMD) of the brachial artery was then measured by ultrasound and expressed as: (maximum artery diameter after release of a blood pressure cuff inflated above systolic pressure-baseline resting diameter)/baseline resting diameter. A 30 microg/m(3) increase in PM(2.5) exposure corresponded to a 0.48% reduction in FMD, P=0.05 representing a 5% relative change in the maximum ability to dilate. Results were consistent between the two bus stops and not sensitive to type of analysis. No significant association was found between FMD and NO(2), PM(1.0) or traffic density. PM(2.5) may reduce the capacity to vasodilate, a potential explanation for the documented association with cardiovascular morbidity.

  13. Redistribution of Decompression Stop Time from Shallow to Deep Stops Increases Incidence of Decompression Sickness in Air Decompression Dives

    Science.gov (United States)

    2011-07-22

    year old active duty male diver surfaced from a 170/30 air dive at <corr>12:11<corr> on 24AUG06 using MK 20 FFM and following the A-2 “deep stops...effort, and this episode responded immediately to pressure. AGE is unlikely due to the experience of the diver, the MK 20 FFM characteristics, and...from a 170/30 air dive at <corr>12:11<corr> on 24AUG06 using MK 20 FFM and following the A-2 “deep stops” experimental decompression profile

  14. Cooling system of the core of a nuclear reactor while it is being stopped or normally operating

    International Nuclear Information System (INIS)

    Tilliette, Z.

    1986-01-01

    The present invention proposes a cooling system with intermediate gas flow which ensures the reactor core cooling when the primary pumps are stopped either directly by means of main heat-exchange circuits ensuring normally the reactor operation, or by means of separated loops, these ones being able so to operate in an autonomous way for they produce their own electricity needs and also an excedent which is added to the power plant production. The cooling circuit and the heat exchanger are described in detail [fr

  15. Cellular Automata Based Modeling for Evaluating Different Bus Stop Designs in China

    Directory of Open Access Journals (Sweden)

    Haoyang Ding

    2015-01-01

    Full Text Available A cellular automaton model is proposed to simulate mixed traffic flow composed of motor vehicles and bicycles near bus stops. Three typical types of bus stops which are common in China are considered in the model, including two types of curbside bus stops and one type of bus bay stops. Passenger transport capacity of three types of bus stops, which is applied to evaluate the bus stop design, is calculated based on the corresponding traffic flow rate. According to the simulation results, the flow rates of both motor vehicles and bicycles exhibit phase transition from free flow to the saturation one at the critical point. The results also show that the larger the interaction between motor vehicle and bicycle flow is near curbside bus stops, the more the value of saturated flows drops. Curbside bus stops are more suitable when the conflicts between two flows are small and the inflow rate of motor vehicles is low. On the contrary, bus bay stops should be applied due to their ability to reduce traffic conflicts. Findings of this study can provide useful suggestions on bus stop selection considering different inflow rate of motor vehicles and bicycles simultaneously.

  16. Leptonic mono-top from single stop production at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Guang Hua [CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics,Chinese Academy of Sciences,Beijing 100190 (China); Hikasa, Ken-ichi [Department of Physics, Tohoku University,Sendai 980-8578 (Japan); Wu, Lei [Department of Physics and Institute of Theoretical Physics, Nanjing Normal University,Nanjing, Jiangsu 210023 (China); ARC Centre of Excellence for Particle Physics at the Terascale,School of Physics, The University of Sydney,NSW 2006 (Australia); Yang, Jin Min [CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics,Chinese Academy of Sciences,Beijing 100190 (China); Department of Physics, Tohoku University,Sendai 980-8578 (Japan); Zhang, Mengchao [Center for Theoretical Physics and Universe, Institute for Basic Science (IBS),Daejeon 34051 (Korea, Republic of)

    2017-03-16

    Top squark (stop) can be produced via QCD interaction but also the electroweak interaction at the LHC. In this paper, we investigate the observability of the associated production of stop and chargino, pp→t̃{sub 1}χ̃{sub 1}{sup −}, in compressed electroweakino scenarios at 14 TeV LHC. Due to small mass splitting between the lightest neutralino (χ̃{sub 1}{sup 0}) and chargino (χ̃{sub 1}{sup −}), the single stop production can give the mono-top signature through the stop decay t̃{sub 1}→tχ̃{sub 1}{sup 0}. We analyze the leptonic mono-top channel of the single stop production and propose a lab-frame observable cos θ{sub bℓ} to reduce the SM backgrounds. We find that such leptonic mono-top events from the single stop production can be probed at 2σ level at the HL-LHC if m{sub t̃{sub 1}}<760 GeV and m{sub χ̃{sub 1{sup 0}}}<150 GeV. Given a discovery of the stop and a measurement of the single stop production cross section, the stop mixing angle can also be determined from the single stop production at the HL-LHC.

  17. Mini-stop bands in single heterojunction photonic crystal waveguides

    KAUST Repository

    Shahid, N.; Amin, M.; Naureen, S.; Anand, S.

    2013-01-01

    Spectral characteristics of mini-stop bands (MSB) in line-defect photonic crystal (PhC) waveguides and in heterostructure PhC waveguides having one abrupt interface are investigated. Tunability of the MSB position by air-fill factor heterostructure PhC waveguides is utilized to demonstrate different filter functions, at optical communication wavelengths, ranging from resonance-like to wide band pass filters with high transmission. The narrowest filter realized has a resonance-like transmission peak with a full width at half maximum of 3.4 nm. These devices could be attractive for coarse wavelength selection (pass and drop) and for sensing applications. 2013 Copyright 2013 Author(s). This article is distributed under a Creative Commons Attribution 3.0 Unported License.

  18. Answers to science questions from the "stop faking it!" guy

    CERN Document Server

    Robertson, William C

    2009-01-01

    This valuable and entertaining compendium of Bill Robertson's popular Science 101 columns, from NSTA member journal Science and Children, proves you don't have to be a science geek to understand basic scientific concepts. The author of the best-selling Stop Faking It! series explains everything from quarks to photosynthesis, telescopes to the expanding universe, and atomic clocks to curveballs all with his trademark wit and irreverence. The 33 short columns, plus a new introduction, provide an introductory science course of sorts, covering topics in life science, Earth and space science, physical science, technology, and more perfect for K-8 teachers, homeschoolers, or parents who just want to boost their science know-how. Easily understood prose and lively illustrations by cartoonist Brian Diskin make this volume an engaging and, more important, readable course you can pass with flying colors.

  19. Pionic annihilation of antiprotons stopped on sup 3 He

    Energy Technology Data Exchange (ETDEWEB)

    Bendiscioli, G.; Filippini, V.; Rotondi, A.; Salvini, P.; Venaglioni, A. (Pavia Univ. (Italy). Dipt. di Fisica Nucleare e Teorica Istituto Nazionale di Fisica Nucleare, Pavia (Italy)); Bossolasco, S.; Bussa, M.P.; Busso, L.; Fava, L.; Ferrero, L.; Maggiora, A.; Panzieri, D.; Piragino, G.; Piragino, R.; Tosello, F. (Turin Univ. (Italy). Ist. di Fisica Generale Istituto Nazionale di Fisica Nucleare, Turin (Italy)); Batusov, Yu.A.; Falomkin, I.V.; Pontecorvo, G.B.; Rozhdestvensky, A.M.; Sapozhnikov, M.G.; Tretyak, V.I. (Joint Inst. for Nuclear Research, Dubna (USSR)); Guaraldo, C. (Istituto Nazionale di Fisica Nucleare, Frascati (Italy). Lab. Nazionale di Frascati); Lodi Rizzini, E. (Brescia Univ. (Italy). Dipt. di Automazione Industriale Istituto Nazionale di Fisica Nucleare, Turin (Italy)); Haatuft, A.; Halsteinslid, A.; Myklebost, K.; Olsen, J.M. (Bergen Univ. (Norway). Dept. of Physics); Breivik, F.O.; Jacobsen, T.; Soerensen, S.O. (Oslo Univ. (Norway). Physics Dept.); Balestra

    1990-11-26

    The pionic annihilation of antiprotons stopped on {sup 3}He nuclei in a self-shunted streamer chamber exposed to the antiproton beam of LEAR is studied. The data concern charged-particle multiplicity distributions, branching ratios for different final states, the probability of final-state interaction, {pi}{sup -}, {pi}{sup +}, p and d momentum spectra, like and unlike pion angular correlations, {pi} and other charged-particle angular correlations. The comparison of the {sup 3}He data with those obtained on {sup 1}H, {sup 2}H and {sup 4}He does not reveal relevant effects due to the increase of the nucleon number; the small differences can be seen as due to a weak final-state interaction. (orig.).

  20. Pionic annihilation of antiprotons stopped on 3He

    International Nuclear Information System (INIS)

    Bendiscioli, G.; Filippini, V.; Rotondi, A.; Salvini, P.; Venaglioni, A.; Bossolasco, S.; Bussa, M.P.; Busso, L.; Fava, L.; Ferrero, L.; Maggiora, A.; Panzieri, D.; Piragino, G.; Piragino, R.; Tosello, F.; Batusov, Yu.A.; Falomkin, I.V.; Pontecorvo, G.B.; Rozhdestvensky, A.M.; Sapozhnikov, M.G.; Tretyak, V.I.; Guaraldo, C.; Haatuft, A.; Halsteinslid, A.; Myklebost, K.; Olsen, J.M.; Zenoni, A.

    1990-01-01

    The pionic annihilation of antiprotons stopped on 3 He nuclei in a self-shunted streamer chamber exposed to the antiproton beam of LEAR is studied. The data concern charged-particle multiplicity distributions, branching ratios for different final states, the probability of final-state interaction, π - , π + , p and d momentum spectra, like and unlike pion angular correlations, π and other charged-particle angular correlations. The comparison of the 3 He data with those obtained on 1 H, 2 H and 4 He does not reveal relevant effects due to the increase of the nucleon number; the small differences can be seen as due to a weak final-state interaction. (orig.)