Performance experiments on the in-vessel core catcher during severe accidents

International Nuclear Information System (INIS)

Kang, Kyoung Ho; Park, Rae Joon; Cho, Young Rho; Kim, Sang Baik

2004-01-01

A US-Korean International Nuclear Energy Research Initiative (INERI) project has been initiated by the Idaho National Engineering and Environmental Laboratory (INEEL), Seoul National University (SNU), Pennsylvania State University (PSU), and the Korean Atomic Energy Research Institute (KAERI) to determine if IVR is feasible for high power reactors up to 1500 MWe by investigating the performance of enhanced ERVC and in-vessel core catcher. This program is initially focusing on the Korean Advanced Power Reactor 1400 MWe (APR1400) design. As for the enhancement of the coolability through the ERVC, boiling tests are conducted by using appropriate coating material on the vessel outer surface to promote downward facing boiling and selecting an improved vessel/insulation design to facilitate water flow and steam venting through the insulation in this program. Another approach for successful IVR are investigated by applying the in-vessel core catcher to provide an 'engineered gap' between the relocated core materials and the water-filled reactor vessel and a preliminary design for an in-vessel core catcher was developed during the first year of this program. Feasibility experiments using the LAVA facility, named LAVA-GAP experiments, are in progress to investigate the core catcher performance based on the conceptual design of the in-vessel core catcher proposed in this INERI project. The experiments were performed using 60kg of Al 2 O 3 thermite melt as a core material simulant with a 1/8 linear scale mock-up of the reactor vessel lower plenum. The hemispherical in-vessel core catcher was installed inside the lower head vessel maintaining a uniform gap of 10mm from the inner surface of the lower head vessel. Two types of the core catchers were used in these experiments. The first one was a single layered in-vessel core catcher without internal coating and the second one was a two layered in-vessel core catcher with an internal coating of 0.5mm-thick ZrO 2 via the plasma

Engineering Protein Hydrogels Using SpyCatcher-SpyTag Chemistry.

Science.gov (United States)

Gao, Xiaoye; Fang, Jie; Xue, Bin; Fu, Linglan; Li, Hongbin

2016-09-12

Constructing hydrogels from engineered proteins has attracted significant attention within the material sciences, owing to their myriad potential applications in biomedical engineering. Developing efficient methods to cross-link tailored protein building blocks into hydrogels with desirable mechanical, physical, and functional properties is of paramount importance. By making use of the recently developed SpyCatcher-SpyTag chemistry, we successfully engineered protein hydrogels on the basis of engineered tandem modular elastomeric proteins. Our resultant protein hydrogels are soft but stable, and show excellent biocompatibility. As the first step, we tested the use of these hydrogels as a drug carrier, as well as in encapsulating human lung fibroblast cells. Our results demonstrate the robustness of the SpyCatcher-SpyTag chemistry, even when the SpyTag (or SpyCatcher) is flanked by folded globular domains. These results demonstrate that SpyCatcher-SpyTag chemistry can be used to engineer protein hydrogels from tandem modular elastomeric proteins that can find applications in tissue engineering, in fundamental mechano-biological studies, and as a controlled drug release vehicle.

A condensed review of the core catcher in the LMR

International Nuclear Information System (INIS)

Lee, Yong Bum; Hahn, Do hee

2001-03-01

The overwhelming emphasis in reactor safety is on the prevention of core meltdown. Moreover, although there have been several accidents that have resulted in some fuel melting, to date there have been no accidents severe enough to cause the syndrome of core collapse, reactor vessel melt-through, containment penetration, and dispersal into the ground. Nevertheless, a number of proposals have been made for the design of core catcher systems to control or stop the motion of the molten core mass should such an accident take place. Core catchers may differ in both their location within the reactor system and in the mechanism that is used to cool and control the motion of the core debris. In this report the classification, configuration and main features of the core catcher are described. And also, the core catcher provisions in constructed and planned LMRs (Liquid Metal Reactors) are summarized

An internal core catcher for a pool L.M.F.B.R. and connected studies

International Nuclear Information System (INIS)

Le Rigoleur, C.; Kayser, G.

1979-01-01

This paper describes an internal core catcher for a pool LMFBR. Problems related to retention of debris are studied: downward progression of debris from the core to the core catcher, debris bed formation, heat transfer below the core catcher plate and to the main vessel, mechanical resistance. These results are used to estimate the performances of the internal core catcher for a given core melt-down-accident. It is seen that for a uniform thickness layer on the core catcher the retention capabilities are satisfactory. Then the problem of a heap of debris is approached. Dryout is studied. Uncertainties related to the bed characteristics and problems of extended dryout beds are put forward

RECOILING MASSIVE BLACK HOLES IN GAS-RICH GALAXY MERGERS

International Nuclear Information System (INIS)

Guedes, Javiera; Madau, Piero; Mayer, Lucio; Callegari, Simone

2011-01-01

The asymmetric emission of gravitational waves produced during the coalescence of a massive black hole (MBH) binary imparts a velocity 'kick' to the system that can displace the hole from the center of its host. Here, we study the trajectories and observability of MBHs recoiling in three (one major, two minor) gas-rich galaxy merger remnants that were previously simulated at high resolution, and in which the pairing of the MBHs had been shown to be successful. We run new simulations of MBHs recoiling in the major merger remnant with Mach numbers in the range 1≤M≤6 and use simulation data to construct a semi-analytical model for the orbital evolution of MBHs in gas-rich systems. We show the following. (1) In major merger remnants the energy deposited by the moving hole into the rotationally supported, turbulent medium makes a negligible contribution to the thermodynamics of the gas. This contribution becomes significant in minor merger remnants, potentially allowing for an electromagnetic signature of MBH recoil. (2) In major merger remnants, the combination of both deeper central potential well and drag from high-density gas confines even MBHs with kick velocities as high as 1200 km s -1 within 1 kpc from the host's center. (3) Kinematically offset nuclei may be observable for timescales of a few Myr in major merger remnants in the case of recoil velocities in the range 700-1000 km s -1 . (4) In minor merger remnants the effect of gas drag is weaker, and MBHs with recoil speeds in the range 300-600 km s -1 will wander through the host halo for longer timescales. When accounting for the probability distribution of kick velocities, however, we find that the likelihood of observing recoiling MBHs in gas-rich galaxy mergers is very low even in the best-case scenario.

Experimental study on natural ventilation performance of one-sided wind catcher

NARCIS (Netherlands)

Montazeri, H.; Azizian, R.

2008-01-01

Hydrodynamic performance of a one-sided wind catcher was investigated by experimental wind tunnel and smoke visualization testing. Wind catchers or what is called Baud-Geers in Persian language was a main component of buildings in central region of Iran and the neighboring countries. A Baud-Geer is

Lifetime measurements using the recoil distance method—achievements and perspectives

Science.gov (United States)

Krücken, R.

2001-07-01

The recoil distance method (RDM) for measuring pico-second nuclear level lifetimes and its use in nuclear structure studies is reviewed and perspectives for the future are presented. High precision measurements in the mass-130 region, studies of multi-phonon states in rare earth nuclei, the investigation of shape coexistence and the recently discovered phenomenon of "magnetic rotation" are reviewed. Prospects for lifetime measurements in exotic regions of nuclei such as the measurement of lifetimes in neutron rich nuclei populated via spontaneous and heavy-ion induced fission are discussed. Other prospects include the use of the RDM technique in conjunction with recoil separators. The relevance of these techniques for experiments with radioactive ion beams will be discussed.

Lifetime measurements using the recoil distance method - achievements and perspectives

International Nuclear Information System (INIS)

Kruecken, R.

2001-01-01

The recoil distance method (RDM) for measuring pico-second nuclear level lifetimes and its use in nuclear structure studies is reviewed and perspectives for the future are presented. High precision measurements in the mass-130 region, studies of multi-phonon states in rare earth nuclei, the investigation of shape coexistence and the recently discovered phenomenon of 'magnetic rotation' are reviewed. Prospects for lifetime measurements in exotic regions of nuclei such as the measurement of lifetimes in neutron rich nuclei populated via spontaneous and heavy-ion induced fission are discussed. Other prospects include the use of the RDM technique in conjunction with recoil separators. The relevance of these techniques for experiments with radioactive ion beams will be discussed

New sacrificial material for ex-vessel core catcher

Energy Technology Data Exchange (ETDEWEB)

Komlev, Andrei A., E-mail: komlev@kth.se [Kungliga Tekniska Högskolan (KTH), AlbaNova University Centre, Nuclear Power Safety Division, Roslagstullsbacken 21, SE-106 91, Stockholm (Sweden); Almjashev, Vyacheslav I., E-mail: vac@mail.ru [A.P. Aleksandrov Research Institute of Technology, NITI, DSAR, Sosnovy Bor, 188540 (Russian Federation); Bechta, Sevostian V., E-mail: bechta@safety.sci.kth.se [Kungliga Tekniska Högskolan (KTH), AlbaNova University Centre, Roslagstullsbacken 21, SE-106 91, Stockholm (Sweden); Khabensky, Vladimir B., E-mail: vladimirkhabensky@gmail.com [A.P. Aleksandrov Research Institute of Technology, NITI, DSAR, Sosnovy Bor, 188540 (Russian Federation); Granovsky, Vladimir S., E-mail: gran@niti.ru [A.P. Aleksandrov Research Institute of Technology, NITI, DSAR, Sosnovy Bor, 188540 (Russian Federation); Gusarov, Victor V., E-mail: victor.v.gusarov@gmail.com [Ioffe Institute, 26 Polytekhnicheskaya Str., St. Petersburg, 194021 (Russian Federation)

2015-12-15

A new functional (sacrificial) material has been developed in the Fe{sub 2}O{sub 3}–SrO–Al{sub 2}O{sub 3}–CaO system based on strontium hexaferrite ceramic in concrete matrix. The method of producing SM has been advanced technologically; this technological effectiveness allows the SM to be used in ex-vessel core catchers with corium spreading as well as in crucible-type core catchers. Critical properties regarding the efficiency of SM in ex-vessel core catchers, such as porosity, pycnometric density, apparent density, solidus and liquidus temperatures, and water content have been measured. Suitable fractions of SrFe{sub 12}O{sub 19} and high alumina cement (HAC) were found in the SM based on thermodynamic analysis of the SM/corium interaction. The use of sacrificial steel as an additional heat adsorption component in the core catcher allowed us to increase the mass fraction range of SrFe{sub 12}O{sub 19} in the SM from 0.3−0.5 to 0.3–0.85. The activation temperature of the SM/corium interaction has been shown to correspond to the liquidus temperature of the local composition at the SM/corium interface. The calculated value of this temperature was 1716 °C. Analysis of phase transformations in the SrO–Fe{sub 2}O{sub 3} system revealed advantages of the SrFe{sub 12}O{sub 19}–based sacrificial material compared with the Fe{sub 2}O{sub 3}-contained material owing to the time proximity of SrFe{sub 12}O{sub 19} decomposition and corium interaction activation. - Highlights: • A sacrificial material (SM) was developed for ex-vessel core catcher. • Suitable proportions in the SrFe{sub 12}O{sub 19}–Al{sub 2}O{sub 3}·CaO–Fe system were determined. • Hydrogen release limitation was shown for ex-vessel corium retention with the SM. • Calculated temperature of the active initiation of corium/SM interaction is 1716 °C. • Functional properties of the SM were measured.

AnimalCatcher: a digital camera to capture various reactions of animals

OpenAIRE

Tsukada, Koji; Oki, Maho; Kurihara, Kazutaka; Furudate, Yuko

2015-01-01

People often have difficulty to take pictures of animals, since animals usually do not react with cameras nor understand verbal directions. To solve this problem, we developed a new interaction technique, AnimalCatcher, which can attract animals' attention easily. The AnimalCatcher shoots various sounds using directional speaker to capture various reactions of animals. This paper describes concepts, implementation, and example pictures taken in a zoo.

Improvements to core-catchers

Energy Technology Data Exchange (ETDEWEB)

Johnson, T C.W.

1969-07-22

A core catcher consists of a generally annular holder adapted to be contained within a core barrel with sets of dogs circumferentially disposed in the holder. Each set of dogs consists of at least 2 dogs of different lengths pivotally mounted in the holder to swing inward. The dogs in each set are vertically superimposed. They are of upward decreasing length, with the arc of swing of the vertically adjacent dogs overlapping. (8 claims)

Experimental Study for Effects of the Stud shape of the Core Catcher System

Energy Technology Data Exchange (ETDEWEB)

Song, Kyusang; Son, Hong Hyun; Jeong, Uiju; Seo, Gwang Hyeok; Shin, Doyoung; Jeun, Gyoodong; Kim, Sung Joong [Hanyang University, Seoul (Korea, Republic of)

2015-05-15

In preparation of potential severe accidents, a nuclear power plant is equipped with diverse systems of engineering safety features or mitigation system dedicated to the severe accidents conditions. As a common strategy, a number of nuclear power plants adopt the in-vessel retention (IVR) and/or external reactor vessel cooling (ERVC) strategies. With the ERVC strategy, an additional system (core catcher system) to catch molten core penetrating the reactor pressure vessel (RPV) was proposed for advanced light water reactor. The core catcher system is for Ex-vessel in the European Advanced Power Reactor 1400 (EU-APR1400) to acquire a European license certificate. It is to confine molten materials in the reactor cavity while keeping coolable geometry in case that the RPV failure occurs. The system consists of a carbon steel body, sacrificial material, protection material and engineered cooling channel. As shown in Fig 1, the engineered cooling channel of the ex-vessel core catcher was adopted to remove sensible heat and decay heat of the molten corium using cooling water flooded from the In-Containment Refueling Water Storage Tank (IRWST) by gravity. A large number of studs are placed in the cooling channel to support the core catcher body. While installation of the studs is unavoidable, the studs tend to interfere in the smooth streamline of the core catcher channel. The distorted streamline could affect the temperature distribution and overall coolability of the system. Thus, it is of importance to investigate the effects of studs on the coolability of the core catcher system. In the current research, to evaluate the effect of a stud on the streamline and natural convective boiling performance, numerical and experimental approaches were taken. As a part of numerical approach, CFD simulation using ANSYS/FLUENT was carried out. The objective was to predict disturbance of the streamline and temperature distribution due to the interference of the studs. Through the CFD

Simulant melt experiments on performance of the in-vessel core catcher

International Nuclear Information System (INIS)

Kyoung-Ho Kang; Rae-Joon Park; Sang-Baik Kim; Suh, K.Y.; Cheung, F.B.; Rempe, J.L.

2005-01-01

Full text of publication follows: LAVA-GAP experiments are in progress to investigate the performance of the in-vessel core catcher using alumina melt as a corium simulant. The hemispherical in-vessel core catcher made of carbon steel was installed inside the lower head vessel with uniform gap of 5 mm or 10 mm to the inner surface of the lower head vessel. As a performance test of the in-vessel core catcher, the effects of base steel and internal coating materials and gap thickness between the core catcher and the lower head vessel were examined in this study. In the LAVA-GAP-2 and LAVA-GAP-3 tests, the base steel was carbon steel and the gap thickness was 10 mm. On the other hand, in the LAVA-GAP-4 and LAVA-GAP-5 tests, the base steel was stainless steel and the gap thickness was 5 mm. Actual composition of the coating material for the LAVA-GAP-4 test was 92% of ZrO 2 - 8% of Y 2 O 3 including 95% of Ni - 5% of Al bond coat same as the LAVA-GAP-3 test. In these tests, the thickness of ZrO 2 internal coating was 0.5 mm. To examine the effects of the coating material, in-vessel core catcher with a 0.6 mm-thick ZrO 2 coating without bond coat was used in the LAVA-GAP-5 test. This report summarizes the experimental results and the post metallurgical inspection results of the LAVA-GAP-4 and LAVA-GAP- 5 tests. In the LAVA-GAP-4 and LAVA-GAP-5 tests, the core catcher was failed and it was stuck to the inner surface of the lower head vessel. LAVA-GAP-4 and LAVA-GAP-5 test results imply that 5 mm thick gap is rather small for sufficient water ingression and steam venting through the gap. In case of small gap size, water is boiled off and steam increases pressure inside the gap and so water can not ingress into the gap at the initial heat up stage. Metallurgical inspections on the test specimens indicate that the internal coating layer might melt totally and dispersed in the base steel and the solidified iron melt and so the detection frequencies of Zr and O are trivial all

Laboratory studies of the meltfront propagation in a borax core-catcher

International Nuclear Information System (INIS)

Dalle Donne, M.; Werle, H.

1980-08-01

A series of seven laboratory experiments concerning the meltdown of a borax core catcher have been performed. By the selection of the simulant materials the most important thermophysical properties of the core catcher materials were taken into account. Fission product heating of the molten core masses was simulated by electrolytically heating of the molten region. The experiments reveal interesting details of the phenomena to be expected during melt-down of a borax core catcher, especially on the flow pattern, the mixing processes of molten materials and the layer formation the melt. The most interesting result is that the ratio of downward to sideward melting rate is heavily reduced by high melting barriers and that a cubic structure of barriers will not equalize downward and sideward melting rates. A super 8 film is available as additional information. (orig.) [de

Recoil ions

International Nuclear Information System (INIS)

Cocke, C.L.; Olson, R.E.

1991-01-01

The collision of a fast moving heavy ion with a neutral atomic target can produce very highly charged but slowly moving target ions. This article reviews experimental and theoretical work on the production and use of recoil ions beyond the second ionization state by beams with specific energies above 0.5 MeV/amu. A brief historical survey is followed by a discussion of theoretical approaches to the problem of the removal of many electrons from a neutral target by a rapid, multiply charged projectile. A discussion of experimental techniques and results for total and differential cross sections for multiple ionization of atomic and molecular targets is given. Measurements of recoil energy are discussed. The uses of recoil ions for in situ spectroscopy of multiply charged ions, for external beams of slow, highly charged ions and in ion traps are reviewed. Some possible future opportunities are discussed. (orig.)

The HERMES recoil detector

International Nuclear Information System (INIS)

Airapetian, A.; Belostotski, S.

2013-02-01

For the final running period of HERA, a recoil detector was installed at the HERMES experiment to improve measurements of hard exclusive processes in charged-lepton nucleon scattering. Here, deeply virtual Compton scattering is of particular interest as this process provides constraints on generalised parton distributions that give access to the total angular momenta of quarks within the nucleon. The HERMES recoil detector was designed to improve the selection of exclusive events by a direct measurement of the four-momentum of the recoiling particle. It consisted of three components: two layers of double-sided silicon strip sensors inside the HERA beam vacuum, a two-barrel scintillating fibre tracker, and a photon detector. All sub-detectors were located inside a solenoidal magnetic field with an integrated field strength of 1Tm. The recoil detector was installed in late 2005. After the commissioning of all components was finished in September 2006, it operated stably until the end of data taking at HERA end of June 2007. The present paper gives a brief overview of the physics processes of interest and the general detector design. The recoil detector components, their calibration, the momentum reconstruction of charged particles, and the event selection are described in detail. The paper closes with a summary of the performance of the detection system.

The HERMES recoil detector

Energy Technology Data Exchange (ETDEWEB)

Airapetian, A. [Giessen Univ. (Germany). Physikalisches Inst.; Michigan Univ., Ann Arbor, MI (United States). Randall Laboratory of Physics; Aschenauer, E.C. [DESY, Zeuthen (Germany); Belostotski, S. [B.P. Konstantinov Petersburg Nuclear Physics Insitute, Gatchina (Russian Federation)] [and others; Collaboration: HERMES Recoil Detector Group

2013-02-15

For the final running period of HERA, a recoil detector was installed at the HERMES experiment to improve measurements of hard exclusive processes in charged-lepton nucleon scattering. Here, deeply virtual Compton scattering is of particular interest as this process provides constraints on generalised parton distributions that give access to the total angular momenta of quarks within the nucleon. The HERMES recoil detector was designed to improve the selection of exclusive events by a direct measurement of the four-momentum of the recoiling particle. It consisted of three components: two layers of double-sided silicon strip sensors inside the HERA beam vacuum, a two-barrel scintillating fibre tracker, and a photon detector. All sub-detectors were located inside a solenoidal magnetic field with an integrated field strength of 1Tm. The recoil detector was installed in late 2005. After the commissioning of all components was finished in September 2006, it operated stably until the end of data taking at HERA end of June 2007. The present paper gives a brief overview of the physics processes of interest and the general detector design. The recoil detector components, their calibration, the momentum reconstruction of charged particles, and the event selection are described in detail. The paper closes with a summary of the performance of the detection system.

Cage effect in recoil studies

International Nuclear Information System (INIS)

Berei, K.

1983-09-01

The role of cage effect is one of the most discussed questions of hot atom chemistry in condensed organic systems. So far no direct evidence is available for assessing the exact contribution of thermal recombinations occurring in the liquid cage to the stabilization processes of recoil atoms. However, some conclusions can be drawn from experimental observations concerning the influence on product yield of hot atom recoil spectra, the effects of density, phase and long range order of the medium as well as from comparisons with systems providing cage walls of different chemical reactivities towards the recoil atom. Recent developments in this field are reviewed based primarily on the investigations of recoil halogen reactions in aliphatic and aromatic hydrocarbons and their haloderivatives. (author)

76 FR 79764 - Requested Administrative Waiver of the Coastwise Trade Laws: Vessel DREAM CATCHER; Invitation for...

Science.gov (United States)

2011-12-22

... DEPARTMENT OF TRANSPORTATION Maritime Administration [Docket No. MARAD-2011-0156] Requested Administrative Waiver of the Coastwise Trade Laws: Vessel DREAM CATCHER; Invitation for Public Comments AGENCY... DREAM CATCHER is: INTENDED COMMERCIAL USE OF VESSEL: ``Passenger charter.'' GEOGRAPHIC REGION: ``Georgia...

Materials interaction tests to identify base and coating materials for an enhanced in-vessel core catcher design

Energy Technology Data Exchange (ETDEWEB)

Rempe, J.L.; Knudson, D.L.; Condie, K.G.; Swank, W.D. [Idaho National Engineering and Environmental Laboratory, Idaho Falls ID (United States); Cheung, F.B. [Pennsylvania State University, Department of Mechanical and Nuclear Engineering, University Park PA (United States); Suh, K.Y. [Seoul National University, Department of Nuclear Engineering, Seoul (Korea, Republic of); Kim, S.B. [Korea Atomic Energy Research Institute, Severe Accident Research Project, Taejon (Korea, Republic of)

2004-07-01

An enhanced in-vessel core catcher is being designed and evaluated, it must ensure In-Vessel Retention of core materials that may relocate under severe accident conditions in advanced reactors. To reduce cost and simplify manufacture and installation, this new core catcher design consists of several interlocking sections that are machined to fit together when inserted into the lower head. If needed, the core catcher can be manufactured with holes to accommodate lower head penetrations. Each section of the core catcher consists of two material layers with an option to add a third layer (if deemed necessary): a base material, which has the capability to support and contain the mass of core materials that may relocate during a severe accident; an insulating oxide coating material on top of the base material, which resists interactions with high-temperature core materials; and an optional coating on the bottom side of the base material to prevent any potential oxidation of the base material during the lifetime of the reactor. Initial evaluations suggest that a thermally-sprayed oxide material is the most promising candidate insulator coating for a core catcher. Tests suggest that 2 coatings can provide adequate protection to a stainless steel core catcher: -) a 500 {mu}m thick zirconium dioxide coating over a 100-200 {mu}m Inconel 718 bond coating, and -) a 500 {mu}m thick magnesium zirconate coating.

Numerical Analysis on Heat Flux Distribution through the Steel Liner of the Ex-vessel Core Catcher

Energy Technology Data Exchange (ETDEWEB)

Oh, Se Hong; Choi, Choeng Ryul [ELSOLTEC, Yongin (Korea, Republic of); Kim, Byung Jo; Lee, Kyu Bok [KEPCO, Gimcheon (Korea, Republic of); Hwang, Do Hyun [KHNP-CRI, Daejeon (Korea, Republic of)

2016-05-15

In order to prevent material failure of steel container of the core catcher system due to high temperatures, heat flux through the steel liner wall must be kept below the critical heat flux (CHF), and vapor dry-out of the cooling channel must be avoided. In this study, CFD methodology has been developed to simulate the heat flux distribution in the core catcher system, involving following physical phenomena: natural convection in the corium pool, boiling heat transfer and solidification/melting of the corium. A CFD methodology has been developed to simulate the thermal/hydraulic phenomena in the core catcher system, and a numerical analysis has been carried out to estimate the heat flux through the steel liner of the core catcher. High heat flux values are formed at the free surface of the corium pool. However, the heat flux through the steel liner is maintained below the critical heat flux.

ZZ RECOIL/B, Heavy Charged Particle Recoil Spectra Library for Radiation Damage Calculation

International Nuclear Information System (INIS)

Gabriel, T.A.; Amburgey, J.D.; Greene, N.M.

1983-01-01

1 - Description of problem or function: Format: GAM-II group structure; Number of groups: 104 neutron and Recoil-energy groups; Nuclides: Elements Included in Charged-Particle Recoil Data Base: Al, W, Ti, Pb, V, Mg, Cr, Be, Mn, C, Fe, Au, Co, Si, Ni, B-10, Cu, B-11, Zr, N, Nb, Li-6, Mo, Li-7, Ta (Data for Ta-181,Ta-182), O, Origin: ENDF/B-IV cross-section data. A heavy charged-particle recoil data base (primary knock-on atom (PKA) spectra) and an analysis program have been created to assist experimentalists in studying, evaluating, and correlating radiation-damage effects in different neutron environments. Since experimentally obtained controlled thermo-nuclear-reactor-type neutron spectra are not presently available, the data base can be extremely useful in relating currently obtainable radiation damage to that which is anticipated in future fusion devices. However, the usefulness of the data base is not restricted to just CTR needs. Most of the elements of interest to the radiation-damage community and all neutron reactions of any significance for these elements have been processed, using available ENDF/B-IV cross-section data, and are included in the data base. Calculated data such as primary recoil spectra, displacement rates, and gas-production rates, obtained with the data base, for different radiation environments are presented and compared with previous calculations. Primary neutrons with energies up to 20 MeV have been considered. The elements included in the data base are listed in Table I. All neutron reactions of significance for these elements (i.e., elastic, inelastic, (n,2n), (n,3n), (n,p), (n,sigma), (n,gamma), etc.,) which have cross sections available from ENDF/B-IV have been processed and placed in the data base. Table I - Elements Included in Charged-Particle Recoil Data Base: Al, W, Ti, Pb, V, Mg, Cr, Be, Mn, C, Fe, Au, Co, Si, Ni, 10 B, Cu, 11 B, Zr, N, Nb, 6 Li, Mo, 7 Li, Ta (Data for Ta 181 ,Ta 182 ), O. 2 - Method of solution: The neutron

D0-brane recoil revisited

Energy Technology Data Exchange (ETDEWEB)

Craps, Ben [Theoretische Natuurkunde, Vrije Universiteit Brussel and The International Solvay Institutes, Pleinlaan 2, B-1050 Brussels (Belgium); Evnin, Oleg [California Institute of Technology 452-48, Pasadena, CA 91125 (United States); Nakamura, Shin [Physics Department, Hanyang University, Seoul, 133-791 (Korea, Republic of)

2006-12-15

One-loop string scattering amplitudes computed using the standard D0-brane conformal field theory (CFT) suffer from infrared divergences associated with recoil. A systematic framework to take recoil into account is the worldline formalism, where fixed boundary conditions are replaced by dynamical D0-brane worldlines. We show that, in the worldline formalism, the divergences that plague the CFT are automatically cancelled in a non-trivial way. The amplitudes derived in the worldline formalism can be reproduced by deforming the CFT with a specific 'recoil operator', which is bilocal and different from the ones previously suggested in the literature.

Evaluation of downmotion time interval molten materials to core catcher during core disruptive accidents postulated in LMFR

International Nuclear Information System (INIS)

Voronov, S.A.; Kiryushin, A.I.; Kuzavkov, N.G.; Vlasichev, G.N.

1994-01-01

Hypothetical core disruptive accidents are postulated to clear potential of a reactor plant to withstand extreme conditions and to generate measures for management and mitigation of accidents consequence. In Russian advanced reactors there is a core catcher below the diagrid to prevent vessel bottom melting and to localize fuel debris. In this paper the calculation technique and estimation of relocation time of molten fuel and materials are presented in the case of core disruptive accidents postulated for LMFR reactor. To evaluate minimum interval of fuel relocation time the calculations for different initial data are provided. Large mass of materials between the core and the catcher in LMFR reactor hinders molten materials relocation toward the vessel bottom. That condition increases the time interval of reaching core catcher by molten fuel. Computations performed allowed to evaluate the minimum molten materials relocation time from the core to the core catcher. This time interval is in a range of 3.5-5.5 hours. (author)

Photofragment angular momentum distribution beyond the axial recoil approximation: Predissociation

International Nuclear Information System (INIS)

Kuznetsov, Vladislav V.; Vasyutinskii, Oleg S.

2007-01-01

We present the quantum mechanical expressions for the angular momentum distribution of the photofragments produced in slow predissociation. The paper is based on our recent theoretical treatment [J. Chem. Phys. 123, 034307 (2005)] of the recoil angle dependence of the photofragment multipole moments which explicitly treat the role of molecular axis rotation on the electronic angular momentum polarization of the fragments. The electronic wave function of the molecule was used in the adiabatic body frame representation. The rigorous expressions for the fragment state multipoles which have been explicitly derived from the scattering wave function formalism have been used for the case of slow predissociation where a molecule lives in the excited quasibound state much longer than a rotation period. Possible radial nonadiabatic interactions were taken into consideration. The optical excitation of a single rotational branch and the broadband incoherent excitation of all possible rotational branches have been analyzed in detail. The angular momentum polarization of the photofragments has been treated in the high-J limit. The polarization of the photofragment angular momenta predicted by the theory depends on photodissociation mechanism and can in many cases be significant

Interpreting Recoil for Undergraduate Students

Science.gov (United States)

Elsayed, Tarek A.

2012-01-01

The phenomenon of recoil is usually explained to students in the context of Newton's third law. Typically, when a projectile is fired, the recoil of the launch mechanism is interpreted as a reaction to the ejection of the smaller projectile. The same phenomenon is also interpreted in the context of the conservation of linear momentum, which is…

Vascular changes of the hand in professional baseball players with emphasis on digital ischemia in catchers.

Science.gov (United States)

Ginn, T Adam; Smith, Adam M; Snyder, Jon R; Koman, L Andrew; Smith, Beth P; Rushing, Julia

2005-07-01

Repetitive trauma to the hand is a concern for baseball players. The present study investigated the effects of repetitive trauma and the prevalence of microvascular pathological changes in the hands of minor league professional baseball players. In contrast to previous investigators, we documented the presence of abnormalities in younger, asymptomatic individuals. Thirty-six baseball players on active minor league rosters underwent a history and physical examination of both hands as well as additional specialized tests, including Doppler ultrasound, a timed Allen test, determination of digital brachial pressure indices, and ring sizing of fingers. Data were compared between gloved hands and throwing hands, hitters and nonhitters, and players at four different positions (catcher [nine subjects], outfielder [seven subjects], infielder [five subjects], and pitcher [fifteen subjects]). Digital brachial indices in the ring fingers of the gloved (p healthy professional baseball players in all positions, with a significantly higher prevalence in catchers, prior to the development of clinically important ischemia. Repetitive trauma resulting from the impact of the baseball also leads to digital hypertrophy in the index finger of the gloved hand of catchers. Gloves currently used by professional catchers do not adequately protect the hand from repetitive trauma.

Recoil mixing in high-fluence ion implantation

International Nuclear Information System (INIS)

Littmark, U.; Hofer, W.O.

1979-01-01

The effect of recoil mixing on the collection and depth distribution of implanted projectiles during high-fluence irradiation of a random solid is investigated by model calculations based on a previously published transport theoretical approach to the general problem of recoil mixing. The most pronounced effects are observed in the maximum implantable amount of projectiles and in the critical fluence for saturation. Both values are significantly increased by recoil mixing. (Auth.)

Complementary scattered and recoiled ion data from TOF-E heavy ion elastic recoil detection analysis

International Nuclear Information System (INIS)

Johnston, P.N.; El Bouanani, M.; Stannard, W.B.; Bubb, I.F.; Cohen, D.D.; Dytlewski, N.; Siegele, R.

1998-01-01

The advantage of Time of Flight and Energy (ToF-E) Heavy Ion Elastic Recoil Detection Analysis (HIERDA) over Rutherford Backscattering (RBS) analysis is its mass and energy dispersive capabilities. The mass resolution of ToF-E HIERDA deteriorates for very heavy elements. The limitation is related to the poor energy resolution of Si detectors for heavy ions. While the energy spectra from ToF-E HIERDA data are normally used to extract depth profiles, this work discusses the benefits of using the time spectra of both the recoiled and the scattered ions for depth profiling. The simulation of the complementary scattered and recoiled ion time spectra improves depth profiling and reduced current limitations when dealing with very heavy ions, such as Pt, Bi, Ta. (authors)

Scintillation efficiency of nuclear recoil in liquid xenon

CERN Document Server

Arneodo, F; Badertscher, A; Benetti, P; Bernardini, E; Bettini, A; Borio di Tigliole, A A; Brunetti, R; Bueno, A G; Calligarich, E; Campanelli, M; Carpanese, C; Cavalli, D; Cavanna, F; Cennini, P; Centro, Sandro; Cesana, A; Cline, D; De Mitri, I; Dolfini, R; Ferrari, A; Gigli-Berzolari, A; Matthey, C; Mauri, F; Mazza, D; Mazzone, L; Meng, G; Montanari, C; Nurzia, G; Otwinowski, S; Palamara, O; Pascoli, D; Pepato, Adriano; Petrera, S; Periale, L; Piano Mortari, G; Piazzoli, A; Picchi, P; Pietropaolo, F; Rancati, T; Rappoldi, A; Raselli, G L; Rebuzzi, D; Revol, Jean Pierre Charles; Rico, J; Rossella, M; Rossi, C; Rubbia, André; Rubbia, Carlo; Sala, P; Scannicchio, D A; Sergiampietri, F; Suzuki, S; Terrani, M; Tian, W; Ventura, Sandro; Vignoli, C; Wang, H; Woo, J; Xu, Z

2000-01-01

We present the results of a test done with a Liquid Xenon (LXe) detector for 'Dark Matter' search, exposed to a neutron beam to produce nuclear recoil events simulating those which would be generated by WIMP's elastic scattering. The aim of the experiment was to measure directly the scintillation efficiency of nuclear recoil. The nuclear recoil considered in the test was in the tens of keV range. The ratio of measured visible energy over the true recoil energy was evaluated to be about 20%, in good agreement with the theoretical predictions.

Ionization and scintillation of nuclear recoils in gaseous xenon

Energy Technology Data Exchange (ETDEWEB)

Renner, J., E-mail: jrenner@lbl.gov [Lawrence Berkeley National Laboratory (LBNL), 1 Cyclotron Road, Berkeley, CA 94720 (United States); Department of Physics, University of California, Berkeley, CA 94720 (United States); Gehman, V.M.; Goldschmidt, A.; Matis, H.S.; Miller, T.; Nakajima, Y.; Nygren, D.; Oliveira, C.A.B.; Shuman, D. [Lawrence Berkeley National Laboratory (LBNL), 1 Cyclotron Road, Berkeley, CA 94720 (United States); Álvarez, V. [Instituto de Física Corpuscular (IFIC), CSIC & Universitat de València, Calle Catedrático José Beltrán, 2, 46980 Paterna, Valencia (Spain); Borges, F.I.G. [Departamento de Fisica, Universidade de Coimbra, Rua Larga, 3004-516 Coimbra (Portugal); Cárcel, S. [Instituto de Física Corpuscular (IFIC), CSIC & Universitat de València, Calle Catedrático José Beltrán, 2, 46980 Paterna, Valencia (Spain); Castel, J.; Cebrián, S. [Laboratorio de Física Nuclear y Astropartículas, Universidad de Zaragoza, Calle Pedro Cerbuna 12, 50009 Zaragoza (Spain); Cervera, A. [Instituto de Física Corpuscular (IFIC), CSIC & Universitat de València, Calle Catedrático José Beltrán, 2, 46980 Paterna, Valencia (Spain); Conde, C.A.N. [Departamento de Fisica, Universidade de Coimbra, Rua Larga, 3004-516 Coimbra (Portugal); and others

2015-09-01

Ionization and scintillation produced by nuclear recoils in gaseous xenon at approximately 14 bar have been simultaneously observed in an electroluminescent time projection chamber. Neutrons from radioisotope α-Be neutron sources were used to induce xenon nuclear recoils, and the observed recoil spectra were compared to a detailed Monte Carlo employing estimated ionization and scintillation yields for nuclear recoils. The ability to discriminate between electronic and nuclear recoils using the ratio of ionization to primary scintillation is demonstrated. These results encourage further investigation on the use of xenon in the gas phase as a detector medium in dark matter direct detection experiments.

Optimizing Higgs factories by modifying the recoil mass

Energy Technology Data Exchange (ETDEWEB)

Gu, Jiayin [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Chinese Academy of Sciences, Beijing (China). Center for Future High Energy Physics; Li, Ying-Ying [Hong Kong Univ. of Science and Technology, Kowloon (China). Dept. of Physics

2017-10-15

It is difficult to measure the WW-fusion Higgs production process (e{sup +}e{sup -}→ν anti νh) at a lepton collider with a center of mass energy of 240-250 GeV due to its small rate and the large background from the Higgsstrahlung process with an invisible Z (e{sup +}e{sup -}→hZ, Z→ν anti ν). We construct a modified recoil mass variable, m{sup p}{sub recoil}, defined using only the 3-momentum of the reconstructed Higgs particle, and show that it can better separate the WW-fusion and Higgsstrahlung events than the original recoil mass variable m{sub recoil}. Consequently, the m{sup p}{sub recoil} variable can be used to improve the overall precisions of the extracted Higgs couplings, in both the conventional framework and the effective-field-theory framework. We also explore the application of the m{sup p}{sub recoil} variable in the inclusive cross section measurements of the Higgsstrahlung process, while a quantitive analysis is left for future studies.

100 group displacement cross sections from RECOIL data base

International Nuclear Information System (INIS)

Gopalakrishnan, V.

1995-01-01

Displacement cross sections in 100 neutron energy groups were calculated from the RECOIL data base using the RECOIL program, for use in DPA (Displacement Per Atom) calculations for FBTR and PFBR materials. 100 group displacement cross sections were calculated using RECOIL-Data Base and RECOIL Program. Modifications were made in the data base to reduce space requirement, and in the program for easy handling on a PC. 2 refs

Calculations with ANSYS/FLOTRAN to a core catcher benchmark

International Nuclear Information System (INIS)

Willschuetz, H.G.

1999-01-01

There are numerous experiments for the exploration of the corium spreading behaviour, but comparable data have not been available up to now in the field of the long-term behaviour of a corium expanded in a core catcher. For the calculations a pure liquid oxidic melt with a homogeneous internal heat source was assumed. The melt was distributed uniformly over the spreading area of the EPR core catcher. All codes applied the well known k-ε-turbulence-model to simulate the turbulent flow regime of this melt configuration. While the FVM-code calculations were performed with three dimensional models using a simple symmetry, the problem was modelled two-dimensionally with ANSYS due to limited CPU performance. In addition, the 2D results of ANSYS should allow a comparison for the planned second stage of the calculations. In this second stage, the behaviour of a segregated metal oxide melt should be examined. However, first estimates and pre-calculations showed that a 3D simulation of the problem is not possible with any of the codes due to lacking computer performance. (orig.)

Chemical effects of fission recoils

International Nuclear Information System (INIS)

Meisels, G.G.; Freeman, J.P.; Gregory, J.P.; Richardson, W.C.; Sroka, G.J.

1978-01-01

The production of nitrogen from nitrous oxide at high density was employed to investigate the energy deposition efficiency of fission recoils produced from fission of U 235 in uranium-palladium foils clad with platinum. Nitrogen production varied linearly with fission recoil dose from 1.1 x 10 20 to 9.0 x 10 20 eV, and was independent of density between 12.5 and 127.5 g l -1 N 2 O. 16.2 +- 0.8% of the fission recoil energy was deposited external to the foil. Electron microprobe analysis showed some unevenness of new foil and polymer buildup on the surface after irradiation of ethylene-oxygen mixtures. Subsequent irradiation in the presence of nitrous oxide restored some of the original efficiency. This is ascribed to chemical oxidation of the polymer induced by reactive intermediates produced from nitrous oxide. (author)

A Preliminary Study of the Core Catcher System on Various Stud Shapes using FLUENT

Energy Technology Data Exchange (ETDEWEB)

Jeong, Uiju; Seo, Gwang Hyeok; Jeun, Gyoodong; Kim, Sung Joong [Hanyang University, Seoul (Korea, Republic of)

2014-10-15

As a kind of in-vessel retention (IVR) strategies, reactor cavity flooding is used for Westinghouse's AP1000 and South Korea's OPR1000. Moreover, the European Pressurized Reactor (EPR) has adopted an ex-vessel core catcher strategy rather than the IVR strategy. Although the mitigation strategies suggested are vigorously considered, there are still various issues due to its uncertainties and complex phenomena during severe accidents. In this study, to assess the effect of studs installed on the core catcher body, a CFD analysis for coolant channels having rectangular or cylinder shaped studs is carried out. In this study, numerical simulations for the different stud shapes of the core catcher system were carried out using ANSYS FLUENT. For a comparison work, the rectangular and cylinder shaped stud were modeled with the same initial and boundary conditions. The major findings observed from this study can be summarized as follows. - The simulation results showed the 31% reduced amount of pressure drop for the case of the cylinder shaped studs as compared with the reference case, which is for the rectangular studs. - The tendency of reduced pressure drop is well in accord with the flow distribution. The fluid velocities around the studs were greatly distorted for the rectangular studs than those around the cylinder studs. - The distorted stream of fluid could affect heat transfer from core catcher body, and result in locally additional damages. This result may suggest the necessity of finding an optimized stud shape. For more improved comparison work, an additional simulation is planned including different stud shapes.

Core catcher cooling for a gas-cooled fast breeder

International Nuclear Information System (INIS)

Dalle Donne, M.; Dorner, S.; Schretzmann, K.

1976-01-01

Water, molten salts, and liquid metals are under discussion as coolants for the core catcher of a gas-cooled fast breeder. The authors state that there is still no technically mature method of cooling a core melt. However, the investigations carried out so far suggest that there is a solution to this problem. (RW/AK) [de

An Evaluation of Magneto Rheological Dampers for Controlling Gun Recoil Dynamics

Directory of Open Access Journals (Sweden)

Mehdi Ahmadian

2001-01-01

Full Text Available The application of magneto rheological dampers for controlling recoil dynamics is examined, using a recoil demonstrator that includes a single-shot 50 caliber BMG rifle action and a MR damper. The demonstrator is selected such that it can adequately represent the velocities that commonly occur in weapons with a recoil system, and can be used for collecting data for analyzing the effects of MR dampers on recoil dynamics. The MR damper is designed so that it can work effectively at the large velocities commonly occurring in gun recoil, and also be easily adjusted to reasonably optimize the damper performance for the recoil demonstrator. The test results show that it is indeed possible to design and use MR dampers for recoil applications, which subject the damper to relative velocities far larger than the applications that such dampers have commonly been used for (i.e., vehicle applications. Further, the results indicate that the recoil force increases and the recoil stroke decreases nonlinearly with an increase in the damping force. Also of significance is the fact that the adjustability of MR dampers can be used in a closed-loop system such that the large recoil forces that commonly occur upon firing the gun are avoided and, simultaneously, the recoil stroke is reduced. This study points to the need for several areas of research including establishing the performance capabilities for MR dampers for gun recoil applications in an exact manner, and the potential use of such dampers for a fire out of battery recoil system.

Gas powered fluid gun with recoil mitigation

Science.gov (United States)

Grubelich, Mark C; Yonas, Gerold

2013-11-12

A gas powered fluid gun for propelling a stream or slug of a fluid at high velocity toward a target. Recoil mitigation is provided that reduces or eliminates the associated recoil forces, with minimal or no backwash. By launching a quantity of water in the opposite direction, net momentum forces are reduced or eliminated. Examples of recoil mitigation devices include a cone for making a conical fluid sheet, a device forming multiple impinging streams of fluid, a cavitating venturi, one or more spinning vanes, or an annular tangential entry/exit.

WIND EROSION INTENSITY DETERMINATION USING SOIL PARTICLE CATCHER DEVICES

Directory of Open Access Journals (Sweden)

Lenka Lackóová

2013-12-01

Full Text Available To analyze wind erosion events in the real terrain conditions, we proposed to construct a prototype of soil particle catcher devices to trap soil particles. With these devices we are able to measure the intensity of wind erosion at six different heights above the soil surface in one location or at three different heights in two places. It is possible to use them for six different places at the same time as well. We performed field measurements to determine the amount of soil particles transported by the wind between 26th – 31st March 2012. Each measuring took 60 minutes. After this time the soil particle catchers were emptied and further measurements carried out. At the beginning we selected two places for measurement (soil HPJ 16 and 37 at two heights, one above the other. Then we used two measuring systems 40 m apart at two sites (D2 and D4 and the soil captured at two heights (0, 1. The maximum weight of soil particles trapped in measuring system D2 at height (0 was 1242.7 g at a wind speed of 9.6 ms-1. At measurement height (1 the maximum weight was 72.7 g trapped at the same average hourly rate, but during different measurement events. The measuring system at D4 trapped the highest amount of soil at a wind speed of 8.9 ms-1 (1141.7 g at height (0 and at a speed of 9.3 ms-1 (22.3 g at height (1. During the measurements with the two basic measuring systems D4 and D2, we measured the wind erosion intensity together with soil particle catchers D1 and D3. D3 was placed between devices D4 and D2, D1 was 20 m ahead D2. Soil particle catchers were placed on the soil surface at height position (0. We measured increasing soil erosion downwind on four locations spaced at 20 m. The results show that with there is an increasing quantity of particles collected as the erosive surface length increases, due to the so-called snowball effect. We analyzed selected trapped soil samples in order to determine the size of the soil particles and their proportion

The Quake-Catcher Network: Bringing Seismology to Homes and Schools

Science.gov (United States)

Lawrence, J. F.; Cochran, E. S.; Christensen, C. M.; Saltzman, J.; Taber, J.; Hubenthal, M.

2011-12-01

The Quake-Catcher Network (QCN) is a collaborative initiative for developing the world's largest, low-cost strong-motion seismic network by utilizing sensors in and attached to volunteer internet-connected computers. QCN is not only a research tool, but provides an educational tool for teaching earthquake science in formal and informal environments. A central mission of the Quake-Catcher Network is to provide scientific educational software and hardware so that K-12 teachers, students, and the general public can better understand and participate in the science of earthquakes and earthquake hazards. With greater understanding, teachers, students, and interested individuals can share their new knowledge, resulting in continued participation in the project, and better preparation for earthquakes in their homes, businesses, and communities. The primary educational outreach goals are 1) to present earthquake science and earthquake hazards in a modern and exciting way, and 2) to provide teachers and educators with seismic sensors, interactive software, and educational modules to assist in earthquake education. QCNLive (our interactive educational computer software) displays recent and historic earthquake locations and 3-axis real-time acceleration measurements. This tool is useful for demonstrations and active engagement for all ages, from K-college. QCN provides subsidized sensors at 49 for the general public and 5 for K-12 teachers. With your help, the Quake-Catcher Network can provide better understanding of earthquakes to a broader audience. Academics are taking QCN to classrooms across the United States and around the world. The next time you visit a K-12 classroom or teach a college class on interpreting seismograms, bring a QCN sensor and QCNLive software with you! To learn how, visit http://qcn.stanford.edu.

Optimizing Higgs factories by modifying the recoil mass

Science.gov (United States)

Gu, Jiayin; Li, Ying-Ying

2018-02-01

It is difficult to measure the WW-fusion Higgs production process ({{{e}}}+{{{e}}}-\\to {{ν }}\\bar{{{ν }}}{{h}}) at a lepton collider with a center of mass energy of 240-250 GeV due to its small rate and the large background from the Higgsstrahlung process with an invisible Z ({{{e}}}+{{{e}}}-\\to {{hZ}},{{Z}}\\to {{ν }}\\bar{{{ν }}}). We construct a modified recoil mass variable, {m}{{recoil}}p, defined using only the 3-momentum of the reconstructed Higgs particle, and show that it can separate the WW-fusion and Higgsstrahlung events better than the original recoil mass variable m recoil. Consequently, the {m}{{recoil}}p variable can be used to improve the overall precisions of the extracted Higgs couplings, in both the conventional framework and the effective-field-theory framework. We also explore the application of the {m}{{recoil}}p variable in the inclusive cross section measurements of the Higgsstrahlung process, while a quantitive analysis is left for future studies. JG is Supported by an International Postdoctoral Exchange Fellowship Program between the Office of the National Administrative Committee of Postdoctoral Researchers of China (ONACPR) and DESY. YYL is Supported by Hong Kong PhD Fellowship (HKPFS) and the Collaborative Research Fund (CRF) (HUKST4/CRF/13G)

Optimal control of gun recoil in direct fire using magnetorheological absorbers

International Nuclear Information System (INIS)

Singh, Harinder J; Wereley, Norman M

2014-01-01

Optimal control of a gun recoil absorber is investigated for minimizing recoil loads and maximizing rate of fire. A multi-objective optimization problem was formulated by considering the mechanical model of the recoil absorber employing a spring and a magnetorheological (MR) damper. The damper forces are predicted by evaluating pressure drops using a nonlinear Bingham-plastic model. The optimization methodology provides multiple optimal design configurations with a trade-off between recoil load minimization and increased rate of fire. The configurations with low or high recoil loads imply low or high rate of fire, respectively. The gun recoil absorber performance is also analyzed for perturbations in the firing forces. The adaptive control of the MR damper for varying gun firing forces provides a smooth operation by returning the recoil mass to its battery position (ready to reload and fire) without incurring an end-stop impact. Furthermore, constant load transmissions are observed with respect to the recoil stroke by implementing optimal control during the simulated firing events. (paper)

Optimal control of gun recoil in direct fire using magnetorheological absorbers

Science.gov (United States)

Singh, Harinder J.; Wereley, Norman M.

2014-05-01

Optimal control of a gun recoil absorber is investigated for minimizing recoil loads and maximizing rate of fire. A multi-objective optimization problem was formulated by considering the mechanical model of the recoil absorber employing a spring and a magnetorheological (MR) damper. The damper forces are predicted by evaluating pressure drops using a nonlinear Bingham-plastic model. The optimization methodology provides multiple optimal design configurations with a trade-off between recoil load minimization and increased rate of fire. The configurations with low or high recoil loads imply low or high rate of fire, respectively. The gun recoil absorber performance is also analyzed for perturbations in the firing forces. The adaptive control of the MR damper for varying gun firing forces provides a smooth operation by returning the recoil mass to its battery position (ready to reload and fire) without incurring an end-stop impact. Furthermore, constant load transmissions are observed with respect to the recoil stroke by implementing optimal control during the simulated firing events.

Thermal-Hydraulic Effects of Stud Shape and Size on the Safety Margin of Core Catcher System

Energy Technology Data Exchange (ETDEWEB)

Song, Kyusang; Son, Hong Hyun; Jeong, Uiju; Kim, Sung Joong [Hanyang University, Seoul (Korea, Republic of)

2015-10-15

With the ERVC strategy, an additional system (core catcher system) to catch molten core penetrating the reactor pressure vessel (RPV) was proposed for advanced light water reactor. The newly engineered corium cooling system, that is, an ex-vessel core catcher system has been designed and adapted in some nuclear power plants such as VVER-1000, EPR, ESBWR, EU-APR1400 to mention a few. For example, Russia adopted a crucible-type core catcher for VVER-1000. On the other hand, a way to catch melt spreading is adopted by several countries, such as EPR in France, ESBWR in USA, ABWR in japan, and EU-APR1400 in Korea In Korea, the core catcher system has been designed and implemented for the European Advanced Power Reactor 1400 (EU-APR1400) to acquire a European license certificate. It is to confine molten materials in the reactor cavity while maintaining a coolable geometry in case that RPV failure occurs. The core catcher system consists of a carbon steel body, sacrificial material, protection material and engineered cooling channel. While installation of the studs is unavoidable, the studs tend to interfere in the smooth streamline of the core catcher channel. The distorted streamline could affect the overall thermal-hydraulic performance including two-phase heat transfer coefficient and critical heat flux (CHF) of the system. Thus, it is of importance to investigate the thermal-hydraulic effects of studs on the coolability, especially the CHF of the core catcher system. With aforementioned importance, pool boiling experiments were carried out with stud shape of, rectangular, cylinder, and elliptic and for stud sizes of 10, 15, 20, and 25 mm under the condition of atmospheric saturated water. A particular attention was focused on observing local vapor behavior around the studs and finding any hot spots, where the vapors are accumulated. The occurrence of the CHF is anticipated at the back side of the studs. The visual observation and CHF measurements indicate that the

Thermal-Hydraulic Effects of Stud Shape and Size on the Safety Margin of Core Catcher System

International Nuclear Information System (INIS)

Song, Kyusang; Son, Hong Hyun; Jeong, Uiju; Kim, Sung Joong

2015-01-01

With the ERVC strategy, an additional system (core catcher system) to catch molten core penetrating the reactor pressure vessel (RPV) was proposed for advanced light water reactor. The newly engineered corium cooling system, that is, an ex-vessel core catcher system has been designed and adapted in some nuclear power plants such as VVER-1000, EPR, ESBWR, EU-APR1400 to mention a few. For example, Russia adopted a crucible-type core catcher for VVER-1000. On the other hand, a way to catch melt spreading is adopted by several countries, such as EPR in France, ESBWR in USA, ABWR in japan, and EU-APR1400 in Korea In Korea, the core catcher system has been designed and implemented for the European Advanced Power Reactor 1400 (EU-APR1400) to acquire a European license certificate. It is to confine molten materials in the reactor cavity while maintaining a coolable geometry in case that RPV failure occurs. The core catcher system consists of a carbon steel body, sacrificial material, protection material and engineered cooling channel. While installation of the studs is unavoidable, the studs tend to interfere in the smooth streamline of the core catcher channel. The distorted streamline could affect the overall thermal-hydraulic performance including two-phase heat transfer coefficient and critical heat flux (CHF) of the system. Thus, it is of importance to investigate the thermal-hydraulic effects of studs on the coolability, especially the CHF of the core catcher system. With aforementioned importance, pool boiling experiments were carried out with stud shape of, rectangular, cylinder, and elliptic and for stud sizes of 10, 15, 20, and 25 mm under the condition of atmospheric saturated water. A particular attention was focused on observing local vapor behavior around the studs and finding any hot spots, where the vapors are accumulated. The occurrence of the CHF is anticipated at the back side of the studs. The visual observation and CHF measurements indicate that the

Heat Transfer Analysis of the European Pressurized Water Reactor (EPR) Core Catcher Test Facility Volley

Energy Technology Data Exchange (ETDEWEB)

Pikkarainen, Mika; Laine, Jani; Purhonen, Heikki; Kyrki-Rajamaeki, Riitta [Lappeenranta University of Technology, P.O. 20 53851 Lappeenranta (Finland); Sairanen, Risto [Radiation and Nuclear Safety Authority, P.O. 14 00881 Helsinki (Finland)

2008-07-01

The EPR is designed to cope with severe accidents, involving core meltdown. A specific melt spreading area has been designed within the containment. This core catcher will be flooded by water, which transfers the decay heat to the containment heat removal system. To improve cooling, horizontal flow channels made of cast iron are located also below the core catcher. STUK, the radiation and nuclear safety authority in Finland, wanted an independent study of the functionality of the core catcher design. Effect of the presence of insulation material and boric acid in the cooling water was to be studied, as well as the general behavior of the system in different phases of the flooding of the core melt spreading area. To verify the function of the core catcher design, a scaled down test facility was built at Lappeenranta University of Technology. Since there are some physical restrictions of a test facility computational tools were applied especially for the tests where steady state conditions could not be reached without endangering the integrity of the test facility. This paper introduces the Volley test facility, computational simulations and compares them with the test results. Simulated temperatures of those Volley tests, which could be run until steady state conditions, are very close to the measured temperatures. It can be concluded also, that the temperatures are evidently below the cast iron melting point with heat fluxes used in the tests, if there is a small flow inside the cooling channels or even in case when only a few adjacent cooling channels are totally dry. (authors)

Heat Transfer Analysis of the European Pressurized Water Reactor (EPR) Core Catcher Test Facility Volley

International Nuclear Information System (INIS)

Pikkarainen, Mika; Laine, Jani; Purhonen, Heikki; Kyrki-Rajamaeki, Riitta; Sairanen, Risto

2008-01-01

The EPR is designed to cope with severe accidents, involving core meltdown. A specific melt spreading area has been designed within the containment. This core catcher will be flooded by water, which transfers the decay heat to the containment heat removal system. To improve cooling, horizontal flow channels made of cast iron are located also below the core catcher. STUK, the radiation and nuclear safety authority in Finland, wanted an independent study of the functionality of the core catcher design. Effect of the presence of insulation material and boric acid in the cooling water was to be studied, as well as the general behavior of the system in different phases of the flooding of the core melt spreading area. To verify the function of the core catcher design, a scaled down test facility was built at Lappeenranta University of Technology. Since there are some physical restrictions of a test facility computational tools were applied especially for the tests where steady state conditions could not be reached without endangering the integrity of the test facility. This paper introduces the Volley test facility, computational simulations and compares them with the test results. Simulated temperatures of those Volley tests, which could be run until steady state conditions, are very close to the measured temperatures. It can be concluded also, that the temperatures are evidently below the cast iron melting point with heat fluxes used in the tests, if there is a small flow inside the cooling channels or even in case when only a few adjacent cooling channels are totally dry. (authors)

A gun recoil system employing a magnetorheological fluid damper

International Nuclear Information System (INIS)

Li, Z C; Wang, J

2012-01-01

This research aims to design and control a full scale gun recoil buffering system which works under real firing impact loading conditions. A conventional gun recoil absorber is replaced with a controllable magnetorheological (MR) fluid damper. Through dynamic analysis of the gun recoil system, a theoretical model for optimal design and control of the MR fluid damper for impact loadings is derived. The optimal displacement, velocity and optimal design rules are obtained. By applying the optimal design theory to protect against impact loadings, an MR fluid damper for a full scale gun recoil system is designed and manufactured. An experimental study is carried out on a firing test rig which consists of a 30 mm caliber, multi-action automatic gun with an MR damper mounted to the fixed base through a sliding guide. Experimental buffering results under passive control and optimal control are obtained. By comparison, optimal control is better than passive control, because it produces smaller variation in the recoil force while achieving less displacement of the recoil body. The optimal control strategy presented in this paper is open-loop with no feedback system needed. This means that the control process is sensor-free. This is a great benefit for a buffering system under impact loading, especially for a gun recoil system which usually works in a harsh environment. (paper)

Sizing of "Mother Ship and Catcher" Concepts for LEO Small Debris Capture

Science.gov (United States)

Bacon, John B.

2009-01-01

Most Low Earth Orbit (LEO) debris lies in a limited number of inclination "bands" associated with launch latitudes, or with specific useful orbit inclinations (such as polar orbits). Such narrow inclination bands generally have a uniform spread over all possible Right Ascensions of Ascending Node (RAANs), creating a different orbit plane for nearly every piece of debris. This complicates concept of rendezvous and capture for debris removal. However, a low-orbiting satellite will always phase in RAAN faster than debris objects in higher orbits at the same inclination, potentially solving the problem. Such a base can serve as a single space-based launch facility (a "mother ship") that can tend and then send tiny individual catcher devices for each debris object, as the facility drifts into the same RAAN as the higher object. This presentation will highlight characteristic system requirements of such an architecture, including structural and navigation requirements, power, mass and dV budgets for both the mother ship and the mass-produced common catcher devices that would clean out selected inclination bands. The altitude and inclination regime over which a band is to be cleared, the size distribution of the debris, and the inclusion of additional mission priorities all affect the sizing of the system. It is demonstrated that major LEO hazardous debris reductions can be realized in each band with a single LEO launch of a single mother ship, with simple attached catchers of total mass less than typical commercial LEO launch capability.

Heat transfer analysis to investigate the core catcher plate assembly in SFR

International Nuclear Information System (INIS)

Patil, Swapnil; Sharma, Anil Kumar; Velusamy, K.; Nashine, B.K.; Selvaraj, P.

2015-01-01

Severe accident scenario in Sodium Cooled Fast Reactor (SFR) is the major concern for public acceptance. After severe accident, the molten core continuously generates substantial decay heat. However, an in-vessel core catcher plate is provided to remove the decay heat passively. The numerical investigation of pool hydraulics phenomena in sodium pool of typical Indian SFR has been carried out. The debris may form a heap with different angle over the core catcher plate due to molten fuel density and interaction force. Therefore, the debris bed with different heap angle has been analyzed for steady and transient state conditions. The governing equation of fluid flow and heat transfer are solved by finite volume method based solver with the k-ε turbulent model. The time period Δ for which temperature is exceeding above safety limit with different debris heap angle have been established. (author)

Nuclear-Recoil Energy Scale in CDMS II Silicon Dark-Matter Detectors

Energy Technology Data Exchange (ETDEWEB)

Agnese, R.; et al.

2018-03-07

The Cryogenic Dark Matter Search (CDMS II) experiment aims to detect dark matter particles that elastically scatter from nuclei in semiconductor detectors. The resulting nuclear-recoil energy depositions are detected by ionization and phonon sensors. Neutrons produce a similar spectrum of low-energy nuclear recoils in such detectors, while most other backgrounds produce electron recoils. The absolute energy scale for nuclear recoils is necessary to interpret results correctly. The energy scale can be determined in CDMS II silicon detectors using neutrons incident from a broad-spectrum $^{252}$Cf source, taking advantage of a prominent resonance in the neutron elastic scattering cross section of silicon at a recoil (neutron) energy near 20 (182) keV. Results indicate that the phonon collection efficiency for nuclear recoils is $4.8^{+0.7}_{-0.9}$% lower than for electron recoils of the same energy. Comparisons of the ionization signals for nuclear recoils to those measured previously by other groups at higher electric fields indicate that the ionization collection efficiency for CDMS II silicon detectors operated at $\\sim$4 V/cm is consistent with 100% for nuclear recoils below 20 keV and gradually decreases for larger energies to $\\sim$75% at 100 keV. The impact of these measurements on previously published CDMS II silicon results is small.

RECOILING SUPERMASSIVE BLACK HOLES IN SPIN-FLIP RADIO GALAXIES

International Nuclear Information System (INIS)

Liu, F. K.; Wang Dong; Chen Xian

2012-01-01

Numerical relativity simulations predict that coalescence of supermassive black hole (SMBH) binaries leads not only to a spin flip but also to a recoiling of the merger remnant SMBHs. In the literature, X-shaped radio sources are popularly suggested to be candidates for SMBH mergers with spin flip of jet-ejecting SMBHs. Here we investigate the spectral and spatial observational signatures of the recoiling SMBHs in radio sources undergoing black hole spin flip. Our results show that SMBHs in most spin-flip radio sources have mass ratio q ∼> 0.3 with a minimum possible value q min ≅ 0.05. For major mergers, the remnant SMBHs can get a kick velocity as high as 2100 km s –1 in the direction within an angle ∼< 40° relative to the spin axes of remnant SMBHs, implying that recoiling quasars are biased to be with high Doppler-shifted broad emission lines while recoiling radio galaxies are biased to large apparent spatial off-center displacements. We also calculate the distribution functions of line-of-sight velocity and apparent spatial off-center displacements for spin-flip radio sources with different apparent jet reorientation angles. Our results show that the larger the apparent jet reorientation angle is, the larger the Doppler-shifting recoiling velocity and apparent spatial off-center displacement will be. We investigate the effects of recoiling velocity on the dust torus in spin-flip radio sources and suggest that recoiling of SMBHs would lead to 'dust-poor' active galactic nuclei. Finally, we collect a sample of 19 X-shaped radio objects and for each object give the probability of detecting the predicted signatures of recoiling SMBH.

Assessment of the MARS Code Using the Two-Phase Natural Circulation Experiments at a Core Catcher Test Facility

Directory of Open Access Journals (Sweden)

Dong Hun Lee

2017-01-01

Full Text Available A core catcher has been developed to maintain the integrity of nuclear reactor containment from molten corium during a severe accident. It uses a two-phase natural circulation for cooling molten corium. Flow in a typical core catcher is unique because (i it has an inclined cooling channel with downwards-facing heating surface, of which flow processes are not fully exploited, (ii it is usually exposed to a low-pressure condition, where phase change causes dramatic changes in the flow, and (iii the effects of a multidimensional flow are very large in the upper part of the core catcher. These features make computational analysis more difficult. In this study, the MARS code is assessed using the two-phase natural circulation experiments that had been conducted at the CE-PECS facility to verify the cooling performance of a core catcher. The code is a system-scale thermal-hydraulic (TH code and has a multidimensional TH component. The facility was modeled by using both one- and three-dimensional components. Six experiments at the facility were selected to investigate the parametric effects of heat flux, pressure, and form loss. The results show that MARS can predict the two-phase flow at the facility reasonably well. However, some limitations are obviously revealed.

Compton recoil electron tracking with silicon strip detectors

International Nuclear Information System (INIS)

O'Neill, T.J.; Ait-Ouamer, F.; Schwartz, I.; Tumer, O.T.; White, R.S.; Zych, A.D.

1992-01-01

The application of silicon strip detectors to Compton gamma ray astronomy telescopes is described in this paper. The Silicon Compton Recoil Telescope (SCRT) tracks Compton recoil electrons in silicon strip converters to provide a unique direction for Compton scattered gamma rays above 1 MeV. With strip detectors of modest positional and energy resolutions of 1 mm FWHM and 3% at 662 keV, respectively, 'true imaging' can be achieved to provide an order of magnitude improvement in sensitivity to 1.6 x 10 - 6 γ/cm 2 -s at 2 MeV. The results of extensive Monte Carlo calculations of recoil electrons traversing multiple layers of 200 micron silicon wafers are presented. Multiple Coulomb scattering of the recoil electron in the silicon wafer of the Compton interaction and the next adjacent wafer is the basic limitation to determining the electron's initial direction

Recoil momenta distributions in the double photoionization

International Nuclear Information System (INIS)

Amusia, M Ya; Liverts, E Z; Drukarev, E G; Mikhai, A I

2014-01-01

We calculate the distributions in recoil momenta for the high energy double photoionization of helium caused by quasifree mechanism. The distributions obtain local maxima at small values of the recoil momenta. This agrees with earlier predictions and recent experimental data. Angular correlations which reach the largest value for 'back-to-back' configuration of photoelectrons are also obtained.

Integrated CFD investigation of heat transfer enhancement using multi-tray core catcher in SFR

International Nuclear Information System (INIS)

Rakhi; Sharma, Anil Kumar; Velusamy, K.

2017-01-01

Highlights: • Heat transfer enhancement using multi-tray core catcher for SFR is investigated. • The capability of a single core collector tray is estimated. • Double and triple collector trays with innovative designs is discussed. • Provision of openings in the trays contributed to enhanced natural circulation. - Abstract: To render future SFR more robust and safe, certain BDBE have been considered in the recent years. A Core Disruptive Accident leading to a whole core meltdown scenario has gained the interest of researchers. Various design concepts and safety measures have been suggested and incorporated in design to address such a low probability scenario. A core catcher concept, in particular, has proved to be inevitable as an in-vessel core retention device in SFR for safe retention of core debris arising out after the severe accident. This study aims to analyse the cooling capability of the innovative design concept of core catcher to remove decay heat of degraded core after the accident. First, the capability of single collection tray is established and then the study is extended to two and three collection trays with different design concepts. Transient forms of governing equations of mass, momentum and energy conservations along with k-ε turbulence model are solved by finite volume based CFD solver. Boussinesq approximation is invoked to model buoyancy in sodium. The study shows that a single collection tray is capable of removing up to 20 MW decay heat load in a typical 500 MWe pool type SFR. Further, studies are carried out to improve the natural circulation of sodium around the source, in the lower plenum and to distribute core debris of the whole core to multiple collection trays. It is found that the double and triple collection trays can accommodate decay loads up to 29 MW. Provision of openings in the collection trays has proved to be effective in improving the heat transfer and sodium flow as well as in distributing the core debris to the

Measurement of Nuclear Recoils in the CDMS II Dark Matter Search

Science.gov (United States)

Fallows, Scott M.

The Cryogenic Dark Matter Search (CDMS) experiment is designed to directly detect elastic scatters of weakly-interacting massive dark matter particles (WIMPs), on target nuclei in semiconductor crystals composed of Si and Ge. These scatters would occur very rarely, in an overwhelming background composed primarily of electron recoils from photons and electrons, as well as a smaller but non-negligible background of WIMP-like nuclear recoils from neutrons. The CDMS~II generation of detectors simultaneously measure ionization and athermal phonon signals from each scatter, allowing discrimination against virtually all electron recoils in the detector bulk. Pulse-shape timing analysis allows discrimination against nearly all remaining electron recoils taking place near detector surfaces. Along with carefully limited neutron backgrounds, this experimental program allowed for "background-free'' operation of CDMS~II at Soudan, with less than one background event expected in each WIMP-search analysis. As a result, exclusionary upper-limits on WIMP-nucleon interaction cross section were placed over a wide range of candidate WIMP masses, ruling out large new regions of parameter space. These results, like any others, are subject to a variety of systematic effects that may alter their final interpretations. A primary focus of this dissertation will be difficulties in precisely calibrating the energy scale for nuclear recoil events like those from WIMPs. Nuclear recoils have suppressed ionization signals relative to electron recoils of the same recoil energy, so the response of the detectors is calibrated differently for each recoil type. The overall normalization and linearity of the energy scale for electron recoils in CDMS~II detectors is clearly established by peaks of known gamma energy in the ionization spectrum of calibration data from a 133Ba source. This electron-equivalent keVee) energy scale enables calibration of the total phonon signal (keVt) by enforcing unity

Recoil-proton fast-neutron counter telescope

Energy Technology Data Exchange (ETDEWEB)

Pavan, P.; Toniolo, D.; Zago, G.; Zannoni, R. (Padua Univ. (Italy). Ist. di Fisica); Galeazzi, G.; Bressanini, G.

1981-12-01

A recoil-proton neutron counter telescope is described composed of a solid-state silicon transmission detector and a NE 102 A plastic scintillator, measuring the energy loss, the energy of the recoil protons and the time of flight between the two detectors. The counter exposed to monoenergetic neutron beams of energy from 6 to 20 MeV presents a low background and a moderate energy resolution. Its absolute efficiency is calculated up to 50 MeV.

Recoil-proton fast-neutron-counter telescope

Energy Technology Data Exchange (ETDEWEB)

Galeazzi, G.; Pavan, P.; Toniolo, D.; Zago, G.; Zannoni, R.; Bressanini, G.

1981-01-01

A proton-recoil neutron counter telescope is described composed of a solid state silicon transmission detector and a NE 102 A plastic scintillator, measuring the energy loss, the energy of the recoil protons and the time-of-flight between the two detectors. The counter exposed to monoenergetic neutron beams of energy from 6 to 20 MeV, presents a low background and a moderate energy resolution. Its absolute efficiency is calculated up to 50 MeV.

KATS experiments to simulate corium spreading in the EPR core catcher concept

International Nuclear Information System (INIS)

Eppinger, B.; Fieg, G.; Schuetz, W.; Stegmaier, U.

2001-01-01

In future Light Water Reactors special devices (core catchers) might be required to prevent containment failure by basement erosion after reactor pressure vessel melt-through during a core meltdown accident. Quick freezing of the molten core masses is desirable to reduce release of radioactivity. Several concepts of core catcher de-vices have been proposed based on the spreading of corium melt onto flat surfaces with subsequent cooling by flooding with water. Therefore a series of experiments to investigate high temperature melt spreading on flat surfaces has been carried out using alumina-iron thermite melts as a simulant. The oxidic thermite melt is conditioned by adding other oxides to simulate a realistic corium melt as close as possible. Spreading of oxidic and metallic melts have been performed in one- and two-dimensional geometry. Substrates were chemically inert ceramic layers, dry concrete and concrete with a shallow water layer on top. (authors)

A study of a wind catcher assisted adsorption cooling channel for natural cooling of a 2-storey building

International Nuclear Information System (INIS)

Haghighi, A.P.; Pakdel, S.H.; Jafari, A.

2016-01-01

This study proposes a new system composing of a wind catcher and a solar driven two-bed silica gel–water adsorption chiller in order to provide natural cooling of a two-story building. The wind catcher provides the required ventilation, and the air flowing though the wind catcher is cooled by the cooling plates fed by the adsorption chiller. The performance of the system is studied theoretically under different ambient conditions such as wind velocity, solar radiation, air temperature and relative humidity. In addition, the influence of geometric parameters such as size of the apertures, wind catcher's height and dimensions of the cooling plates and the number of them are studied. Furthermore, the system's capability to provide thermal comfort in the living space is investigated. It is found that at lower ACH (air change per hour) values, inlet air's temperature and absolute humidity reduce more. In addition, with the rise of the cooling plates' length, the cooling effect increases. The results indicated that with the increase of ACH values, thermal comfort condition is achieved for larger cooling demands. Furthermore, the system was found to be able to cool the air between 10 and 20 °C under different ambient conditions. - Highlights: • A new system consisting of a wind catcher and a solar adsorption chiller is proposed. • The values of ACH were compared under different geometrical parameters. • With the increase of ACH, thermal comfort can be achieved for larger cooling demands. • Thermal comfort is achieved for a maximum of 2200 W cooling demand in a 50 m 3 room. • Application of the system is found to be beneficial in hot and humid climates.

Time-of-flight scattering and recoiling spectrometry

International Nuclear Information System (INIS)

Rabalais, J.W.

1991-01-01

Ion scattering and recoiling spectrometry consists of directing a collimated beam of monoenergetic ions towards a surface and measuring the flux of scattered and recoiled particles from this surface. When the neutral plus ion flux is velocity selected by measuring the flight times from the sample to the detector, the technique is called time-of-flight scattering and recoiling spectrometry (TOF-SARS). TOF-SARS is capable of (1) surface elemental analysis by applying classical mechanics to the velocities of the particles, (2) surface structural analysis by monitoring the angular anisotropies in the particle flux, and (3) ion-surface electron exchange probabilities by analysis of the ion/neutral fractions in the particle flux. Examples of these three areas are presented herein

DSA lifetime measurements in 21Ne at high recoil velocity

International Nuclear Information System (INIS)

Grawe, H.; Heidinger, F.; Kaendler, K.

1977-01-01

States in 21 Ne up to 5 MeV excitation energy have been populated using the inverted reaction 2 H( 20 Ne,pγ). The Doppler shift attenuation (DSA) analysis of the pγ coincidence spectra taken in a Ge(Li) detector at 45 0 and 135 0 and an annular silicon surface barrier detector near 0 0 yielded the lifetimes of 8 states in 21 Ne. Due to the large recoil of vi/c approximately equal to 4% three new lifetimes were determined for the short lived levels at 2.80, 4.68 and 4.73 MeV, namely 10 +- 4 fs, 16 +- 4 fs and 10 +- 4 fs, respectively. The results are compared with rotational and shell model calculations. (orig.) [de

Materials problems related to the core catcher of sodium cooled reactors

International Nuclear Information System (INIS)

Goetzmann, O.

1975-05-01

There are in principal two possible solutions for the external core catcher as far as materials are concerned. 1) A barrier consisting of a material with a high melting point, 2) a tray of comparatively low melting material with a high solubility for the fuel. In case of the first concept one has to look for materials whose melting temperatures are above the temperature of the molten core. Based on metallurgical reasons it seems very likely that the molten core does not exceed a temperature in the range between 2,500 and 2,800 0 C. Due to the compatibility situation with the molten core only a few high melting oxides will be suitable as liner materials for a core catcher. In the second case basalt or concrete, if free of water and lime, are suitable materials. Graphite is a high melting material, however, due to its behaviour with the molten core it should be listed under the second group. By the reaction of graphite with the core materials the melt can be kept liquid down to temperatures of around 1,100 0 C. The evolution of CO by this reaction should be supportable. It is an endothermal reaction. Experiments on the behaviour of core catcher materials have shown that sodium is capable of penetrating into sintered bodies of UO 2 with densities of 90% TD at temperatures higher than 200 0 C. This may lead to the desintegration of these bodies. The exposure to moist air has not done much harm to UO 2 pellets of densities from 80 to 90% TD. Even after one year of exposure, swelling or desintegration could not be observed. Sodium is also capable of penetrating into bodies of synthetic carbon and graphite. Only well graphitized material will not be destroyed. (orig.) [de

Further work on sodium borates as sacrificial materials for a core-catcher

International Nuclear Information System (INIS)

Dalle Donne, M.; Dorner, S.; Roth, A.; Werle, H.

1982-01-01

Sodium borates are suitable low melting point sacrificial materials for a core-catcher of a fast reactor. Concept, design and initial development work have been described previously. Here we report on the measurements of density, volumetric thermal expansion coefficients and viscosity of borax and sodium metaborate, pure and with various percentages of dissolved UO 2 . The density of these molten salts was measured with the buoyancy method in the temperature range 850 - 1300 0 C, while the viscosity was measured in the temperature range 700 - 1250 0 C with a Haake viscosity balance. Simulation experiments with low melting point materials were performed to investigate the ratio of the downward to sideward melt velocity. The results of these experiments show that this ratio is equal to 0.34 for a solid to liquid density ratio rho = 1.66. For the real borax core-catcher rho = 4 and this would correspond to a velocity ratio of about one

Recoil effects of neutron-irradiated metal salts

International Nuclear Information System (INIS)

Lee, B.H.

1980-01-01

The distribution of sup(56)Mn and sup(38)Cl recoil species following radiative neutron capture permanganates, chlorates and perchlorates has been investigated by using ion-exchange chromatography method. The whole of the sup(56)Mn radioactivity in permanganates appeared in two valence states, the sup(38)Cl radioactivity in chlorates in two valence states and also the sup(38)Cl radioactivity in perchlorates in three valence states. Recoil energy was calculated. The internal conversion of sup(38m)Cl isomer transition affects the retention value. The greater the radii of the cation, the higher is the probability of the recoil atom breaking through the secondary cage. In ammonium salt, the ammonium ion behaves as a reducing agent. Crystal structures with their greater free space have shown by retention. (Author)

Transportation system of recoil nucleus by helium jet

International Nuclear Information System (INIS)

Cabral, S.C.; Borges, A.M.; Lemos Junior, O.F.; Auler, L.T.; Silva, A.G. da

1981-01-01

The transportation system of recoil nucleus by helium jet, is studied. It is used a technique aiming to put in the detection area (region of low background) the recoils, produced by nuclear reactions between target and particle beams, those produced with the help of cyclotron CV-28. (E.G.) [pt

Development of an online preparation system for multitracer solutions

Energy Technology Data Exchange (ETDEWEB)

Kasamatsu, Yoshitaka [Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043 (Japan); Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan)], E-mail: kasamatsu.yoshitaka@jaea.go.jp; Yatsukawa, Makoto; Sato, Wataru; Ninomiya, Kazuhiko; Ohki, Toshihiro; Takahashi, Naruto [Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043 (Japan); Yokoyama, Akihiko [Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, Ishikawa 920-1192 (Japan); Kikunaga, Hidetoshi [Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, Ishikawa 920-1192 (Japan); RIKEN, Wako, Saitama 351-0198 (Japan); Kinoshita, Norikazu [Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, Ishikawa 920-1192 (Japan); Shibata, Sadao [Nuclear Safety Technology Center, Rokkasho, Aomori 039-3212 (Japan); Shinohara, Atsushi [Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043 (Japan)

2008-03-15

We have developed a new target-irradiation system for the online preparation of multitracer solutions, where the nuclear-reaction products recoiling out of the target are directly implanted in a solvent as a liquid catcher. A rapid online transportation of the solution has enabled highly efficient recovery of the multitracer solutions having even short-lived radioactive isotopes without any chemical treatments. It has been suggested that the collection efficiency depends on the chemical properties of the recoil elements.

Development of an online preparation system for multitracer solutions

International Nuclear Information System (INIS)

Kasamatsu, Yoshitaka; Yatsukawa, Makoto; Sato, Wataru; Ninomiya, Kazuhiko; Ohki, Toshihiro; Takahashi, Naruto; Yokoyama, Akihiko; Kikunaga, Hidetoshi; Kinoshita, Norikazu; Shibata, Sadao; Shinohara, Atsushi

2008-01-01

We have developed a new target-irradiation system for the online preparation of multitracer solutions, where the nuclear-reaction products recoiling out of the target are directly implanted in a solvent as a liquid catcher. A rapid online transportation of the solution has enabled highly efficient recovery of the multitracer solutions having even short-lived radioactive isotopes without any chemical treatments. It has been suggested that the collection efficiency depends on the chemical properties of the recoil elements

Recoil properties of antimony isotopes produced by the reaction of 570 MeV and 18.2 GeV protons with uranium

CERN Document Server

Hagebø, E

1969-01-01

Using the method of thick target and thick catchers, the ranges and other recoil properties of 13 (12) antimony isotopes between A = 115 and A = 131 (130) have been measured for the reaction of 570 MeV (18·2 GeV) protons with uranium. The kinetic energies T are almost independent of product mass number at 570 MeV but show a strong dependence at 18·2 GeV, the lightest isotopes having only about half the kinetic energy of the heavy ones. \\\\ \\\\The cascade deposition energies for production of antimony isotopes are almost equal at 570 MeV and 18·2 GeV and fit well to straight lines of the form E$^{∗}$ (A, Z) = E$^{∗}$ (A$_{0}$, Z) + b(A − A$_{0}$). Exceptions are the cascade deposition energies for $^{115}$Sb and $^{116}$Sb which seem to be somewhat too high at 18·2 GeV. By comparison with other work it seems that the slope $b$ of these lines is independent of product element, target and of proton irradiation energy above 450 MeV. \\\\ \\\\If we assume at 570 MeV, that the fissioning nucleus is a uranium ...

The influence of target properties on nuclear spectroscopy measurements

International Nuclear Information System (INIS)

Dionisio, J.S.; Vieu, C.; Lagrange, J.M.; Pautrat, M.; Vanhorenbeeck, J.; Passoja, A.

1988-01-01

A broad review of different kinds of in-beam nuclear spectroscopy measurements particularly influenced by the target properties is outlined. To illustrate such an influence a few typical examples of in-beam electron and gamma-ray spectroscopy measurements, performed at the Orsay MP Tandem accelerator, are reported. In particular several applications of the recoil ion catcher method in the study of short-lived nuclear isomers (with half-lives between ten and few hundred nanoseconds) are briefly described. This method is operated mostly with a pulsed heavy ion beam, bombarding a thin self-supported target but avoiding hitting the catcher foil. Moreover, the time of flight filtering properties of this experimental device is improved by a fast detection of compound nucleus deexcitation (performed with an array of several BaF 2 crystals). This kind of measurement shows clearly the importance of the target qualities as well as the need of good focusing properties and time structure for the accelerated particle beam. Finally, the required characteristics of the targets and recoil stopper foils needed for these measurements (and similar ones performed with the recoil ion shadow method) are analyzed in detail for a few typical experimental arrangements. (author). Abstract only

Heavy quark symmetry at large recoil: The case of baryons

International Nuclear Information System (INIS)

Koerner, J.G.; Kroll, P.

1992-02-01

We analyze the large recoil behaviour of heavy baryon transition form factors in semi-leptonic decays. We use a generalized Brodsky-Lepage hard scattering formalism where diquarks are considered as quasi-elementary constituents of baryons. In the limit of infinitely heavy quark masses the large recoil form factors exhibit a new model-independent heavy quark symmetry which is reminiscent but not identical to the Isgur-Wise symmetry at low recoil. (orig.)

The rotationally induced quadrupole pair field in the particle-rotor model

International Nuclear Information System (INIS)

Almberger, J.

1980-04-01

A formalism is developed which makes it possible to consider the influence of the rotationally induced quadrupole pair field and corresponding quasi-particle residual interactions within the particle-rotor model. The Y 21 pair field renormalizes both the Coriolis and the recoil interactions. (Auth.)

Recoil release of fission products from nuclear fuel

International Nuclear Information System (INIS)

Wise, C.

1985-01-01

An analytical approximation is developed for calculating recoil release from nuclear fuel into gas filled interspaces. This expression is evaluated for a number of interspace geometries and shown to be generally accurate to within about 10% by comparison with numerical calculations. The results are applied to situations of physical interest and it is demonstrated that recoil can be important when modelling fission product release from low temperature CAGR pin failures. Furthermore, recoil can contribute significantly in experiments on low temperature fission product release, particularly where oxidation enhancement of this release is measured by exposing the fuel to CO 2 . The calculations presented here are one way of allowing for this, other methods are suggested. (orig.)

Shallow doping of gallium arsenide by recoil implantation

International Nuclear Information System (INIS)

Sadana, D.K.; Souza, J.P. de; Rutz, R.F.; Cardone, F.; Norcott, M.H.

1989-01-01

Si atoms were recoil-implanted into GaAs by bombarding neutral (As + ) or dopant (Si + ) ions through a thin Si cap. The bombarded samples were subsequently rapid thermally or furnace annealed at 815-1000 degree C in Ar or arsine ambient. The presence of the recoiled Si in GaAs and resulting n + -doping was confirmed by secondary ion mass spectrometry and Hall measurements. It was found that sheet resistance of 19 cm 3 and the annealing temperature was > 850 degree C. The present electrical data show that the recoil implant method is a viable alternative to direct shallow implant for n + doping of GaAs. 7 refs., 3 figs., 1 tab

A recoil-proton fast-neutron counter telescope

International Nuclear Information System (INIS)

Pavan, P.; Toniolo, D.; Zago, G.; Zannoni, R.; Galeazzi, G.; Bressanini, G.

1981-01-01

A recoil-proton neutron counter telescope is described composed of a solid-state silicon transmission detector and a NE 102 A plastic scintillator, measuring the energy loss, the energy of the recoil protons and the time of flight between the two detectors. The counter exposed to monoenergetic neutron beams of energy from 6 to 20 MeV presents a low background and a moderate energy resolution. Its absolute efficiency is calculated up to 50 MeV. (author)

CFD-calculations to a core catcher benchmark

International Nuclear Information System (INIS)

Willschuetz, H.G.

1999-04-01

There are numerous experiments for the exploration of the corium spreading behaviour, but comparable data have not been available up to now in the field of the long term behaviour of a corium expanded in a core catcher. The difficulty consists in the experimental simulation of the decay heat that can be neglected for the short-run course of events like relocation and spreading, which must, however, be considered during investigation of the long time behaviour. Therefore the German GRS, defined together with Battelle Ingenieurtechnik a benchmark problem in order to determine particular problems and differences of CFD codes simulating an expanded corium and from this, requirements for a reasonable measurement of experiments, that will be performed later. First the finite-volume-codes Comet 1.023, CFX 4.2 and CFX-TASCflow were used. To be able to make comparisons to a finite-element-code, now calculations are performed at the Institute of Safety Research at the Forschungszentrum Rossendorf with the code ANSYS/FLOTRAN. For the benchmark calculations of stage 1 a pure and liquid melt with internal heat sources was assumed uniformly distributed over the area of the planned core catcher of a EPR plant. Using the Standard-k-ε-turbulence model and assuming an initial state of a motionless superheated melt several large convection rolls will establish within the melt pool. The temperatures at the surface do not sink to a solidification level due to the enhanced convection heat transfer. The temperature gradients at the surface are relatively flat while there are steep gradients at the ground where the no slip condition is applied. But even at the ground no solidification temperatures are observed. Although the problem in the ANSYS-calculations is handled two-dimensional and not three-dimensional like in the finite-volume-codes, there are no fundamental deviations to the results of the other codes. (orig.)

Preliminary design of a borax internal core-catcher for a gas cooled fast reactor

International Nuclear Information System (INIS)

Dalle Donne, M.; Dorner, S.; Schumacher, G.

1976-09-01

Preliminary thermal calculations show that a core-catcher appears to be feasible, which is able to cope with the complete meltdown of the core and blankets of a 1,000 MWe GCFR. This core-catcher is based on borax (Na 2 B 4 O 7 ) as dissolving material of the oxide fuel and of the fission products occuring in oxide form. The borax is contained in steel boxes forming a 2.1 meter thick slab on the base of the reactor cavity inside the prestressed concrete reactor vessel, just underneath the reactor core. The fission products are dispersed in the pool formed by the liquid borax. The heat power density in the pool is conveniently reduced and the resulting heat fluxes at the borders of the pool can be safely carried away through the PCRV liner and its water cooling system. (orig.) [de

Submillisecond Elastic Recoil Reveals Molecular Origins of Fibrin Fiber Mechanics

Science.gov (United States)

Hudson, Nathan E.; Ding, Feng; Bucay, Igal; O’Brien, E. Timothy; Gorkun, Oleg V.; Superfine, Richard; Lord, Susan T.; Dokholyan, Nikolay V.; Falvo, Michael R.

2013-01-01

Fibrin fibers form the structural scaffold of blood clots. Thus, their mechanical properties are of central importance to understanding hemostasis and thrombotic disease. Recent studies have revealed that fibrin fibers are elastomeric despite their high degree of molecular ordering. These results have inspired a variety of molecular models for fibrin’s elasticity, ranging from reversible protein unfolding to rubber-like elasticity. An important property that has not been explored is the timescale of elastic recoil, a parameter that is critical for fibrin’s mechanical function and places a temporal constraint on molecular models of fiber elasticity. Using high-frame-rate imaging and atomic force microscopy-based nanomanipulation, we measured the recoil dynamics of individual fibrin fibers and found that the recoil was orders of magnitude faster than anticipated from models involving protein refolding. We also performed steered discrete molecular-dynamics simulations to investigate the molecular origins of the observed recoil. Our results point to the unstructured αC regions of the otherwise structured fibrin molecule as being responsible for the elastic recoil of the fibers. PMID:23790375

Direct Measurement of Photon Recoil from a Levitated Nanoparticle

Science.gov (United States)

Jain, Vijay; Gieseler, Jan; Moritz, Clemens; Dellago, Christoph; Quidant, Romain; Novotny, Lukas

2016-06-01

The momentum transfer between a photon and an object defines a fundamental limit for the precision with which the object can be measured. If the object oscillates at a frequency Ω0 , this measurement backaction adds quanta ℏΩ0 to the oscillator's energy at a rate Γrecoil, a process called photon recoil heating, and sets bounds to coherence times in cavity optomechanical systems. Here, we use an optically levitated nanoparticle in ultrahigh vacuum to directly measure Γrecoil. By means of a phase-sensitive feedback scheme, we cool the harmonic motion of the nanoparticle from ambient to microkelvin temperatures and measure its reheating rate under the influence of the radiation field. The recoil heating rate is measured for different particle sizes and for different excitation powers, without the need for cavity optics or cryogenic environments. The measurements are in quantitative agreement with theoretical predictions and provide valuable guidance for the realization of quantum ground-state cooling protocols and the measurement of ultrasmall forces.

On the M\\"ossbauer effect and the rigid recoil question

OpenAIRE

Davidson, Mark

2016-01-01

Various theories for the M\\"ossbauer rigid-recoil effect, which enables a crystal to absorb momentum but not appreciable energy, are compared. These suggest that the recoil may not be instantaneous, and that the recoil time could be used to distinguish between them. An experiment is proposed to measure this time. The idea is to use a small sphere whose outer surface is coated with an electrically charged M\\"ossbauer-active element, and then to measure the amount of energy lost due to Bremmsst...

Hydrogen analysis by elastic recoil spectrometry

International Nuclear Information System (INIS)

Tirira, J.; Trocellier, P.

1989-01-01

An absolute, quantitative procedure was developed to determine the hydrogen content and to describe its concentration profile in the near-surface region of solids. The experimental technique used was the elastic recoil detection analysis of protons induced by 4 He beam bombardment in the energy range <=1.8 MeV. The hydrogen content was calculated using a new recoil cross section expression. The analyses were performed in silicon crystals implanted with hydrogen at 10 keV. The implantation dose was evaluated with an accuracy of 10% and the hydrogen depth profile with that of +-10 nm around 200 nm. (author) 10 refs.; 3 figs

Submillisecond elastic recoil reveals molecular origins of fibrin fiber mechanics.

Science.gov (United States)

Hudson, Nathan E; Ding, Feng; Bucay, Igal; O'Brien, E Timothy; Gorkun, Oleg V; Superfine, Richard; Lord, Susan T; Dokholyan, Nikolay V; Falvo, Michael R

2013-06-18

Fibrin fibers form the structural scaffold of blood clots. Thus, their mechanical properties are of central importance to understanding hemostasis and thrombotic disease. Recent studies have revealed that fibrin fibers are elastomeric despite their high degree of molecular ordering. These results have inspired a variety of molecular models for fibrin's elasticity, ranging from reversible protein unfolding to rubber-like elasticity. An important property that has not been explored is the timescale of elastic recoil, a parameter that is critical for fibrin's mechanical function and places a temporal constraint on molecular models of fiber elasticity. Using high-frame-rate imaging and atomic force microscopy-based nanomanipulation, we measured the recoil dynamics of individual fibrin fibers and found that the recoil was orders of magnitude faster than anticipated from models involving protein refolding. We also performed steered discrete molecular-dynamics simulations to investigate the molecular origins of the observed recoil. Our results point to the unstructured αC regions of the otherwise structured fibrin molecule as being responsible for the elastic recoil of the fibers. Copyright © 2013 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Recoil ion charge state distributions in low energy Arq+ - Ar collisions

International Nuclear Information System (INIS)

Vancura, J.; Marchetti, V.; Kostroun, V.O.

1992-01-01

We have measured the recoil ion charge state distributions in Ar q+ -- Ar (8≤q≤16) collisions at 2.3 qkeV and 0.18qkeV by time of flight (TOF) spectroscopy. For Ar 8-16+ , recoil ion charge states up to 6+ are clearly present, indicating that the 3p subshell in the target atom is being depleted, while for Ar 10-16+ , there is evidence that target 3s electrons are also being removed. Comparison of the recoil ion charge state spectra at 2.3 and 0.18 qkeV shows that for a given projectile charge, there is very little dependence of the observed recoil target charge state distribution on projectile energy

Enhancing the sensitivity of recoil-beta tagging

International Nuclear Information System (INIS)

Henderson, J; Jenkins, D G; Davies, P J; Henry, T W; Joshi, P; Nichols, A J; Ruotsalainen, P; Scholey, C; Auranen, K; Grahn, T; Greenlees, P T; Herzáň, A; Jakobsson, U; Julin, R; Juutinen, S; Konki, J; Leino, M; Pakarinen, J; Lotay, G; Obertelli, A

2013-01-01

Tagging with β-particles at the focal plane of a recoil separator has been shown to be an effective technique for the study of exotic proton-rich nuclei. This article describes three new pieces of apparatus used to greatly improve the sensitivity of the recoil-beta tagging technique. These include a highly-pixelated double-sided silicon strip detector, a plastic phoswich detector for discriminating high-energy β-particles, and a charged-particle veto box. The performance of these new detectors is described and characterised, and the resulting improvements are discussed.

The Dream Catcher Meditation: a therapeutic technique used with American Indian adolescents.

Science.gov (United States)

Robbins, R

2001-01-01

This article describes a short-term treatment insight-oriented model for American Indian adolescents, called Dream Catcher Meditation. It is aimed at helping clients' express unconscious conflicts and to facilitate differentiation and healthy mutuality. Though its duration can vary, twelve sessions are outlined here. Session descriptions include goals and sample questions. Also included are anecdotal material and reflections about cultural relevancy.

A supersonic jet target for the cross section measurement of the 12C(α, γ)16O reaction with the recoil mass separator ERNA

Science.gov (United States)

Rapagnani, D.; Buompane, R.; Di Leva, A.; Gialanella, L.; Busso, M.; De Cesare, M.; De Stefano, G.; Duarte, J. G.; Gasques, L. R.; Morales Gallegos, L.; Palmerini, S.; Romoli, M.; Tufariello, F.

2017-09-01

12C(α, γ)16O cross section plays a key-role in the stellar evolution and nucleosynthesis of massive stars. Hence, it must be determined with the precision of about 10% at the relevant Gamow energy of 300 keV. The ERNA (European Recoil mass separator for Nuclear Astrophysics) collaboration measured, for the first time, the total cross section of 12C(α, γ)16O by means of the direct detection of the 16O ions produced in the reaction down to an energy of Ecm = 1.9 MeV. To extend the measurement at lower energy, it is necessary to limit the extension of the He gas target. This can be achieved using a supersonic jet, where the oblique shock waves and expansion fans formed at its boundaries confine the gas, which can be efficiently collected using a catcher. A test version of such a system has been designed, constructed and experimentally characterized as a bench mark for a full numerical simulation using FV (Finite Volume) methods. The results of the commissioning of the jet test version and the design of the new system that will be used in combination with ERNA are presented and discussed.

Comparison of the Recoil of Conventional and Electromagnetic Cannon

Directory of Open Access Journals (Sweden)

Edward M. Schmidt

2001-01-01

Full Text Available The recoil from an electromagnetic (EM railgun is discussed and compared with that from conventional, propellant gas driven cannon. It is shown that, under similar launch conditions, the recoil of the EM gun is less than that of the powder gun; however, use of a muzzle brake on a powder gun can alter this relative behavior.

Self-triggering detectors for recoil nuclei

International Nuclear Information System (INIS)

Aleksanyan, A.S.; Asatiani, T.I.; Gasparyan, A.O.

1975-01-01

Hybrid α-detectors consisting of wide gap spark chambers and signal α detectors are described. The investigations have been carried out with γ-beams of Yerevan Electron Synchrotron. The possibility of using such detectors in the experiments on particle photoproduction on gas helium with the determination of the interaction point, emission angle of the recoil nucleus and its energy by means of range measurement has been shown. It has been shown that self - triggering wide gap spark chamber allows to detect and measure the range of the recoil nuclei α-particles with energies Esub(α) > or approximately (1 - 2) Mev which correspond to momentum transfers apprxomation (10 -2 - 10 -3 ) (GeV/c) 2

Experimental and numerical study on natural ventilation performance of various multi-opening wind catchers

NARCIS (Netherlands)

Montazeri, H.

2011-01-01

Wind catcher as a natural ventilation system is increasingly used in modern buildings to minimize the consumption of non-renewable energy and reduce the harmful emissions. Height, cross section of the air passages and also place and the number of openings are the main factors which affect the

Flow Boiling on a Downward-Facing Inclined Plane Wall of Core Catcher

International Nuclear Information System (INIS)

Kim, Hyoung Tak; Bang, Kwang Hyun; Suh, Jung Soo

2013-01-01

In order to investigate boiling behavior on downward-facing inclined heated wall prior to the CHF condition, an experiment was carried out with 1.2 m long rectangular channel, inclined by 10 .deg. from the horizontal plane. High speed video images showed that the bubbles were sliding along the heated wall, continuing to grow and combining with the bubbles growing at their nucleation sites in the downstream. These large bubbles continued to slide along the heated wall and formed elongated slug bubbles. Under this slug bubble thin liquid film layer on the heated wall was observed and this liquid film prevents the wall from dryout. The length, velocity and frequency of slug bubbles sliding on the heated wall were measured as a function of wall heat flux and these parameters were used to develop wall boiling model for inclined, downward-facing heated wall. One approach to achieve coolable state of molten core in a PWR-like reactor cavity during a severe accident is to retain the core melt on a so-called core catcher residing on the reactor cavity floor after its relocation from the reactor pressure vessel. The core melt retained in the core catcher is cooled by water coolant flowing in an inclined cooling channel underneath as well as the water pool overlaid on the melt layer. Two-phase flow boiling with downward-facing heated wall such as this core catcher cooling channel has drawn a special attention because this orientation of heated wall may reach boiling crisis at lower heat flux than that of a vertical or upward-facing heated wall. Nishikawa and Fujita, Howard and Mudawar, Qiu and Dhir have conducted experiments to study the effect of heater orientation on boiling heat transfer and CHF. SULTAN experiment was conducted to study inclined large-scale structure coolability by water in boiling natural convection. In this paper, high-speed visualization of boiling behavior on downward-facing heated wall inclined by 10 .deg. is presented and wall boiling model for the

Commissioning of a proton-recoil spectrometer

International Nuclear Information System (INIS)

Nunes, J.C.; Faught, R.T.

2000-01-01

Measurements of neutron fluence spectra in fields from bare and heavy-water-moderated 252 Cf were made with a commercially available proton-recoil spectrometer (PRS) that covers 50 keV to 4.5 MeV. Data obtained from these measurements were compared with data from Bonner sphere spectrometry, Monte Carlo simulation and the open literature. Alterations to the input data file used in unfolding recoil-proton pulse-height distributions were made. Understanding the reasons for these changes and considering the effects of some of the results in an appreciation of the significance of parameters used in the unfolding. An uncertainty of 10% is estimated for values of fluence and ambient dose equivalent for the energy region covered by this PRS. (author)

D-particle Recoil Space Times and "Glueball" Masses

CERN Document Server

Mavromatos, Nikolaos E; Mavromatos, Nick E.; Winstanley, Elizabeth

2001-01-01

We discuss the properties of matter in a D-dimensional anti-de-Sitter-type space time induced dynamically by the recoil of a very heavy D(irichlet)-particle defect embedded in it. The particular form of the recoil geometry, which from a world-sheet view point follows from logarithmic conformal field theory deformations of the pertinent sigma-models, results in the presence of both infrared and ultraviolet (spatial) cut-offs. These are crucial in ensuring the presence of mass gaps in scalar matter propagating in the D-particle recoil space time. The analogy of this problem with the Liouville-string approach to QCD, suggested earlier by John Ellis and one of the present authors, prompts us to identify the resulting scalar masses with those obtained in the supergravity approach based on the Maldacena's conjecture, but without the imposition of any supersymmetry in our case. Within reasonable numerical uncertainties, we observe that agreement is obtained between the two approaches for a particular value of the ra...

Study of heat removal by natural convection from the internal core catcher in PFBR using water model experiments

International Nuclear Information System (INIS)

Jasmin Sudha, A.; Punitha, G.; Das, S.K.; Lydia, G.; Murthy, S.S.; Malarvizhi, B.; Harvey, J.; Kannan, S.E.

2005-01-01

Full text of publication follows: In the event of a core meltdown accident in a Fast Breeder Reactor, the molten core material settling on the bottom of the main vessel can endanger the structural integrity of the main vessel. In the design of Prototype Fast Breeder Reactor in India, the construction of which is about to commence, a core catcher is provided as the internal core retention device to collect and retain the core debris in a coolable configuration. Heat transfer by natural convection above and below the core catcher plate, in the zone beneath the core support structure is evaluated from water mockup experiments in the 1:4 geometrically scaled setup. These studies were undertaken towards comparison of experimentally measured temperatures at different locations with the numerical results. The core catcher assembly consists of a core catcher plate, a heat shield plate and a chimney. Decay heat from the core debris is simulated by electrical heating of the heat shield plate. An opening is provided in the cover plate to reproduce the situation in the actual accident where the core debris would have breached a part of the core support structure. Experiments were carried out with different heat flux levels prevailing upon the heat shield plate. Temperature monitoring was done at more than 100 locations, distributed both on the solid components and in water. The temperature data was analysed to get the temperature profile at different steady state conditions. Flow visualisation was also carried out using water soluble dye to establish the direction of the convective currents. The captured images show that water flows through the slots provided in the top portion of the chimney in the upward direction as evidenced from the diffusion of dye injected inside the chimney. Both the temperature data and flow visualisation confirm mixing of water through the opening in the core support structure which indicates that natural convection is set up in that zone

Reprint of: A supersonic jet target for the cross section measurement of the 12C(α, γ)16O reaction with the recoil mass separator ERNA

Science.gov (United States)

Rapagnani, D.; Buompane, R.; Di Leva, A.; Gialanella, L.; Busso, M.; De Cesare, M.; De Stefano, G.; Duarte, J. G.; Gasques, L. R.; Morales Gallegos, L.; Palmerini, S.; Romoli, M.; Tufariello, F.

2018-01-01

12C(α, γ)16O cross section plays a key-role in the stellar evolution and nucleosynthesis of massive stars. Hence, it must be determined with the precision of about 10% at the relevant Gamow energy of 300 keV. The ERNA (European Recoil mass separator for Nuclear Astrophysics) collaboration measured, for the first time, the total cross section of 12C(α, γ)16O by means of the direct detection of the 16O ions produced in the reaction down to an energy of Ecm = 1.9 MeV. To extend the measurement at lower energy, it is necessary to limit the extension of the He gas target. This can be achieved using a supersonic jet, where the oblique shock waves and expansion fans formed at its boundaries confine the gas, which can be efficiently collected using a catcher. A test version of such a system has been designed, constructed and experimentally characterized as a bench mark for a full numerical simulation using FV (Finite Volume) methods. The results of the commissioning of the jet test version and the design of the new system that will be used in combination with ERNA are presented and discussed.

Signal yields of keV electronic recoils and their discrimination from nuclear recoils in liquid xenon

Science.gov (United States)

Aprile, E.; Aalbers, J.; Agostini, F.; Alfonsi, M.; Amaro, F. D.; Anthony, M.; Arneodo, F.; Barrow, P.; Baudis, L.; Bauermeister, B.; Benabderrahmane, M. L.; Berger, T.; Breur, P. A.; Brown, A.; Brown, E.; Bruenner, S.; Bruno, G.; Budnik, R.; Bütikofer, L.; Calvén, J.; Cardoso, J. M. R.; Cervantes, M.; Cichon, D.; Coderre, D.; Colijn, A. P.; Conrad, J.; Cussonneau, J. P.; Decowski, M. P.; de Perio, P.; di Gangi, P.; di Giovanni, A.; Diglio, S.; Eurin, G.; Fei, J.; Ferella, A. D.; Fieguth, A.; Fulgione, W.; Gallo Rosso, A.; Galloway, M.; Gao, F.; Garbini, M.; Geis, C.; Goetzke, L. W.; Grandi, L.; Greene, Z.; Grignon, C.; Hasterok, C.; Hogenbirk, E.; Howlett, J.; Itay, R.; Kaminsky, B.; Kazama, S.; Kessler, G.; Kish, A.; Landsman, H.; Lang, R. F.; Lellouch, D.; Levinson, L.; Lin, Q.; Lindemann, S.; Lindner, M.; Lombardi, F.; Lopes, J. A. M.; Mahlstedt, J.; Manfredini, A.; Maris, I.; Marrodán Undagoitia, T.; Masbou, J.; Massoli, F. V.; Masson, D.; Mayani, D.; Messina, M.; Micheneau, K.; Molinario, A.; Morâ, K.; Murra, M.; Naganoma, J.; Ni, K.; Oberlack, U.; Pakarha, P.; Pelssers, B.; Persiani, R.; Piastra, F.; Pienaar, J.; Pizzella, V.; Piro, M.-C.; Plante, G.; Priel, N.; Ramírez García, D.; Rauch, L.; Reichard, S.; Reuter, C.; Rizzo, A.; Rupp, N.; Saldanha, R.; Dos Santos, J. M. F.; Sartorelli, G.; Scheibelhut, M.; Schindler, S.; Schreiner, J.; Schumann, M.; Scotto Lavina, L.; Selvi, M.; Shagin, P.; Shockley, E.; Silva, M.; Simgen, H.; Sivers, M. V.; Stein, A.; Thers, D.; Tiseni, A.; Trinchero, G.; Tunnell, C.; Vargas, M.; Wang, H.; Wang, Z.; Wei, Y.; Weinheimer, C.; Wittweg, C.; Wulf, J.; Ye, J.; Zhang, Y.; Zhu, T.; Xenon Collaboration

2018-05-01

We report on the response of liquid xenon to low energy electronic recoils below 15 keV from beta decays of tritium at drift fields of 92 V /cm , 154 V /cm and 366 V /cm using the XENON100 detector. A data-to-simulation fitting method based on Markov Chain Monte Carlo is used to extract the photon yields and recombination fluctuations from the experimental data. The photon yields measured at the two lower fields are in agreement with those from literature; additional measurements at a higher field of 366 V /cm are presented. The electronic and nuclear recoil discrimination as well as its dependence on the drift field and photon detection efficiency are investigated at these low energies. The results provide new measurements in the energy region of interest for dark matter searches using liquid xenon.

First measurement of the ionization yield of nuclear recoils in liquid argon

Energy Technology Data Exchange (ETDEWEB)

Joshi, T. [Univ. of California, Berkeley, CA (United States). Dept. of Nuclear Engineering; Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Sangiorgio, Samuele [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Bernstein, A. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Foxe, Michael P. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Pennsylvania State Univ., University Park, PA (United States). Dept. of Mechanical and Nuclear Engineering; Hagmann, Chris [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Jovanovic, Igor [Pennsylvania State Univ., University Park, PA (United States). Dept. of Mechanical and Nuclear Engineering; Kazkaz, K. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Mozin, Vladimir V. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Norman, E. B. [Univ. of California, Berkeley, CA (United States). Dept. of Nuclear Engineering; Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Pereverzev, S. V. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Rebassoo, Finn O. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Sorensen, Peter F. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)

2014-05-01

Liquid phase argon has long been used as a target medium for particle detection via scintillation light. Recently there has been considerable interest in direct detection of both hypothetical darkmatter particles and coherent elastic neutrino nucleus scattering. These as-yet unobserved neutral particle interactions are expected to result in a recoiling argon atom O(keV), generally referred to in the literature as a nuclear recoil. This prompts the question of the available electromagnetic signal in a liquid argon detector. In this Letter we report the first measurement of the ionization yield (Qy), detected electrons per unit energy, resulting from nuclear recoils in liquid argon, measured at 6.7 keV. This is also the lowest energy measurement of nuclear recoils in liquid argon.

Karakteristike trzanja elektromagnetskog topa / Recoil characteristics of an electromagnetic rail gun

Directory of Open Access Journals (Sweden)

Zoran B. Ristić

2009-10-01

Full Text Available U radu je razmatrano trzanje elektromagnetskog šinskog topa i upoređeno sa trzanjem konvencionalnog topa sa barutnim punjenjem. Zaključuje se da je kod elektromagnetskog topa trzanje manje nego kod topa sa barutnim punjenjem. Takođe, pokazano je da pri istim uslovima lansiranja upotreba gasne kočnice topa sa barutnim punjenjem može izmeniti karakteristike trzanja i više ih približiti ponašanju elektromagnetskog topa. / In this paper the electromagnetic rail gun recoil is discussed and compared with the recoil of a conventional, propellant gas driven gun. It is shown that, under similar launch conditions, the recoil of an electromagnetic gun is weaker than that of the powder-driven gun. The use of a muzzle brake on a powder-driven gun can alter its recoil characteristics and make its behavior closer to that of the electromagnetic rail gun.

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

Sonic Rarefaction Wave Low Recoil Gun

National Research Council Canada - National Science Library

Kathe, E

2002-01-01

A principal challenge faced by the U.S. Army TACOM-ARDEC Benet Laboratories in the design of armaments for lightweight future fighting vehicles with lethality overmatch is mitigating the deleterious effects of large caliber cannon recoil...

Recoil implantation of boron into silicon by high energy silicon ions

Science.gov (United States)

Shao, L.; Lu, X. M.; Wang, X. M.; Rusakova, I.; Mount, G.; Zhang, L. H.; Liu, J. R.; Chu, Wei-Kan

2001-07-01

A recoil implantation technique for shallow junction formation was investigated. After e-gun deposition of a B layer onto Si, 10, 50, or 500 keV Si ion beams were used to introduce surface deposited B atoms into Si by knock-on. It has been shown that recoil implantation with high energy incident ions like 500 keV produces a shallower B profile than lower energy implantation such as 10 keV and 50 keV. This is due to the fact that recoil probability at a given angle is a strong function of the energy of the primary projectile. Boron diffusion was showed to be suppressed in high energy recoil implantation and such suppression became more obvious at higher Si doses. It was suggested that vacancy rich region due to defect imbalance plays the role to suppress B diffusion. Sub-100 nm junction can be formed by this technique with the advantage of high throughput of high energy implanters.

A recoil detector of Koala experiment at HESR

Energy Technology Data Exchange (ETDEWEB)

Xu, Huagen [Forschungszentrum Juelich (Germany)

2015-07-01

The concept of the luminosity detector for the PANDA experiment is based on measuring antiproton-proton elastic scattering in the Coulomb-nuclear interference region by 4 planes of HV-MAPS tracking detectors. The absolute precision is limited by the lack of existing data of the physics quantities σ{sub tot}, ρ and b describing the differential cross section as a function of squared 4-momentum transfer t in the relevant beam momentum region. Therefore, the so-called Koala experiment has been proposed to measure antiproton-proton elastic scattering. The goal of Koala experiment is to measure a wide range of t-distribution to determine the parameters σ{sub tot}, ρ and b. The idea is to measure the scattered beam antiprotons at forward angles by tracking detectors and the recoil target protons near 90 {sup circle} by energy detectors. In order to validate this method a recoil detector has been designed and built. Commissioning of the recoil detector by measuring proton-proton elastic scattering has been performed at COSY. Preliminary results of the commissioning are presented.

Elastic recoil detection analysis of ferroelectric films

Energy Technology Data Exchange (ETDEWEB)

Stannard, W.B.; Johnston, P.N.; Walker, S.R.; Bubb, I.F. [Royal Melbourne Inst. of Tech., VIC (Australia); Scott, J.F. [New South Wales Univ., Kensington, NSW (Australia); Cohen, D.D.; Dytlewski, N. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

1996-12-31

There has been considerable progress in developing SrBi{sub 2}Ta{sub 2}O{sub 9} (SBT) and Ba{sub O.7}Sr{sub O.3}TiO{sub 3} (BST) ferroelectric films for use as nonvolatile memory chips and for capacitors in dynamic random access memories (DRAMs). Ferroelectric materials have a very large dielectric constant ( {approx} 1000), approximately one hundred times greater than that of silicon dioxide. Devices made from these materials have been known to experience breakdown after a repeated voltage pulsing. It has been suggested that this is related to stoichiometric changes within the material. To accurately characterise these materials Elastic Recoil Detection Analysis (ERDA) is being developed. This technique employs a high energy heavy ion beam to eject nuclei from the target and uses a time of flight and energy dispersive (ToF-E) detector telescope to detect these nuclei. The recoil nuclei carry both energy and mass information which enables the determination of separate energy spectra for individual elements or for small groups of elements In this work ERDA employing 77 MeV {sup 127}I ions has been used to analyse Strontium Bismuth Tantalate thin films at the heavy ion recoil facility at ANSTO, Lucas Heights. 9 refs., 5 figs.

Elastic recoil detection analysis of ferroelectric films

Energy Technology Data Exchange (ETDEWEB)

Stannard, W B; Johnston, P N; Walker, S R; Bubb, I F [Royal Melbourne Inst. of Tech., VIC (Australia); Scott, J F [New South Wales Univ., Kensington, NSW (Australia); Cohen, D D; Dytlewski, N [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

1997-12-31

There has been considerable progress in developing SrBi{sub 2}Ta{sub 2}O{sub 9} (SBT) and Ba{sub O.7}Sr{sub O.3}TiO{sub 3} (BST) ferroelectric films for use as nonvolatile memory chips and for capacitors in dynamic random access memories (DRAMs). Ferroelectric materials have a very large dielectric constant ( {approx} 1000), approximately one hundred times greater than that of silicon dioxide. Devices made from these materials have been known to experience breakdown after a repeated voltage pulsing. It has been suggested that this is related to stoichiometric changes within the material. To accurately characterise these materials Elastic Recoil Detection Analysis (ERDA) is being developed. This technique employs a high energy heavy ion beam to eject nuclei from the target and uses a time of flight and energy dispersive (ToF-E) detector telescope to detect these nuclei. The recoil nuclei carry both energy and mass information which enables the determination of separate energy spectra for individual elements or for small groups of elements In this work ERDA employing 77 MeV {sup 127}I ions has been used to analyse Strontium Bismuth Tantalate thin films at the heavy ion recoil facility at ANSTO, Lucas Heights. 9 refs., 5 figs.

Penetration of HEPA filters by alpha recoil aerosols

International Nuclear Information System (INIS)

McDowell, W.J.; Seeley, F.G.; Ryan, M.T.

1976-01-01

The self-scattering of alpha-active substances has long been recognized and is attributed to expulsion of aggregates of atoms from the surface of alpha-active materials by alpha emission recoil energy, and perhaps to further propulsion of these aggregates by subsequent alpha recoils. Workers at the University of Lowell recently predicted that this phenomenon might affect the retention of alpha-active particulate matter by HEPA filters, and found support in experiments with 212 Pb. Tests at Oak Ridge National Laboratory have confirmed that alpha-emitting particulate matter does penetrate high-efficiency filter media, such as that used in HEPA filters, much more effectively than do non-radioactive or beta-gamma active aerosols. Filter retention efficiencies drastically lower than the 99.9 percent quoted for ordinary particulate matter were observed with 212 Pb, 253 Es, and 238 Pu sources, indicating that the phenomenon is common to all of these and probably to all alpha-emitting materials of appropriate half-life. Results with controlled air-flow through filters in series are consistent with the picture of small particles dislodged from the ''massive'' surface of an alpha-active material, and then repeatedly dislodged from positions on the filter fibers by subsequent alpha recoils. The process shows only a small dependence on the physical form of the source material. Oxide dust, nitrate salt, and plated metal all seem to generate the recoil particles effectively. The amount penetrating a series of filters depends on the total amount of activity in the source material, its specific activity, and the length of time of air flow

Recoil transporter devices

International Nuclear Information System (INIS)

Madhavan, N.

2005-01-01

The study of sparsely produced nuclear reaction products in the direction of intense primary beam is a challenging task, the pursuit of which has given rise to the advent or several types of selective devices. These range from a simple parallel plate electrostatic deflector to state-of-the-art electromagnetic separators. There is no single device which can satisfy all the requirements of an ideal recoil transporter, simultaneously. An overview of such devices and their building blocks is presented, which may help in the proper choice of the device as per the experimental requirements. (author)

Nuclear reactions excited by recoil protons on a nuclear reactor

International Nuclear Information System (INIS)

Mukhammedov, S.; Khaydarov, A.; Barsukova, E.G.

2006-01-01

The nuclear reactions excited by recoil protons and of the detection possibility of the various chemical elements with the use of these secondary nucleus reactions were investigated. The recoil protons are produced on a nuclear reactor in the result of (n, p) inelastic and elastic scattering interaction of fast neutrons with nuclei of hydrogen. It is well known that the share of fast neutrons in energetic spectrum of reactor's neutrons in comparison with the share of thermal neutrons is small. . Consequently, the share of recoil protons produced in the result of fast neutron interaction with nuclei of light elements, capable to cause the nuclear reactions, is also small, des, due to Coulomb barrier of nuclei the recoil protons can cause the nuclear reactions only on nuclei of light and some middle elements. Our studies show that observable yields have radio nuclides excited in the result of nuclear reactions on Li, B, O, V and Cu. Our experimental results have demonstrated that the proton activation analysis based on the application of secondary nuclear reactions is useful technique to determine large contents of various light and medium chemical elements. Detection limits for studied chemical elements are estimated better than 10 ppm

Measurements of recoil and projectile momentum distributions for 19-MeV F9+ + Ne collisions

International Nuclear Information System (INIS)

Frohne, V.; Cheng, S.; Ali, R.M.; Raphaelian, M.L.; Cocke, C.L.; Olson, R.

1996-01-01

The collision system of 19-MeV F 9+ on Ne has been studied using recoil and projectile momentum spectroscopy. For each event, identified by final recoil and projectile charge state, the three-dimensional momentum vector of the recoil ion and the transverse momentum vector of the projectile ion were measured. The transverse momenta of the recoil and projectile ions were found to be equal in magnitude and opposite in direction, indicating that the transverse momentum exchange is dominated by interactions between the two ion cores. The transverse momentum distributions are well described by nCTMC calculations. The longitudinal momentum distributions of the recoil ions show that a large fraction of the momentum transferred to the projectile is carried off by continuum electrons. The recoil ions are scattered slightly backward, in partial agreement with predictions of nCTMC calculations. copyright 1996 The American Physical Society

Energy and depth resolution in elastic recoil coincidence spectrometry

Energy Technology Data Exchange (ETDEWEB)

Szilagyi, E., E-mail: szilagyi@rmki.kfki.h [KFKI Research Institute for Particle and Nuclear Physics, P.O. Box 49, H-1525 Budapest (Hungary)

2010-06-15

Elastic recoil coincidence spectrometry was implemented into the analytical ion beam simulation program DEPTH. In the calculations, effective detector geometry and multiple scattering effects are considered. Mott's cross section for the identical, spin zero particles is included. Spectra based on the individual detector signal and summing the energy of the recoiled and scattered particles originating from the same scattering events can also be calculated. To calculate this latter case, the dependency of the energy spread contributions had to be reconsidered.

Energy and depth resolution in elastic recoil coincidence spectrometry

International Nuclear Information System (INIS)

Szilagyi, E.

2010-01-01

Elastic recoil coincidence spectrometry was implemented into the analytical ion beam simulation program DEPTH. In the calculations, effective detector geometry and multiple scattering effects are considered. Mott's cross section for the identical, spin zero particles is included. Spectra based on the individual detector signal and summing the energy of the recoiled and scattered particles originating from the same scattering events can also be calculated. To calculate this latter case, the dependency of the energy spread contributions had to be reconsidered.

Exclusive ρ0 production measured with the HERMES recoil detector

International Nuclear Information System (INIS)

Perez Benito, Roberto Francisco

2010-12-01

The Hermes experiment (HERa MEasurement of Spin) at Desy was designed to study the spin structure of the nucleon in semi-inclusive deep inelastic scattering. The internal structure of the nucleon has been investigated in detail and it has been measured that the intrinsic quark spin contribution is only about 30% of the total spin of the nucleon. A formalism to describe the internal structure of the nucleon called Generalised Patron Distributions (GPDs) was developed recently to understand the fundamental structure of the nucleon. These GPDs can be accessed by the measurement of hard exclusive reactions and hard exclusive processes that can be understood in terms of GPDs. The accumulated Hermes data offer access to GPDs in different combinations of beam charge and beam and target helicity asymmetries. To improve exclusivity and to enhance the resolution of kinematic variables to study hard exclusive processes which provide access to the GPDs and hence to the orbital angular momentum of the quarks, in January 2006 a Recoil Detector was installed that surrounded the internal gas target of the Hermes experiment. The Hermes Recoil Detector consisted of three components: a silicon strip detector inside the vacuum, a scintillating fiber tracker and the photon detector. All three detectors were located inside a solenoidal magnet which provided a 1T longitudinal magnetic field. The Recoil Detector improves the selection of exclusive events by a direct measurement of the momentum and track position of the recoiling particle as well as by rejecting non-exclusive background. This detector was an ideal novel tool to combine energy and position measurements for charged particles in a momentum range of 0.1 to 1.4 GeV/c. The Recoil Detector was fully commissioned and operating. Data was taken continuously until the final Hera shutdown in July of 2007. In this thesis we report on the performance of the Recoil Detector and more specifically about the scintillating fiber tracker

Understanding "The Catcher in the Rye": A Student Casebook to Issues, Sources, and Historical Documents.

Science.gov (United States)

Pinsker, Sanford; Pinsker, Ann

The social, cultural, and historical documents and commentary in this casebook illuminate the reading of "The Catcher in the Rye," a novel that has become an important rite of passage for many young adults. In addition to a literary analysis, the casebook acquaints students with the larger world in which Holden Caulfield, the…

The FRS Ion Catcher : A facility for high-precision experiments with stopped projectile and fission fragments

NARCIS (Netherlands)

Plass, W. R.; Dickel, T.; Purushothaman, S.; Dendooven, P.; Geissel, H.; Ebert, J.; Haettner, E.; Jesch, C.; Ranjan, M.; Reiter, M. P.; Weick, H.; Amjad, F.; Ayet, S.; Diwisch, M.; Estrade, A.; Farinon, F.; Greiner, F.; Kalantar-Nayestanaki, N.; Knoebel, R.; Kurcewicz, J.; Lang, J.; Moore, I.; Mukha, I.; Nociforo, C.; Petrick, M.; Pfuetzner, M.; Pietri, S.; Prochazka, A.; Rink, A. -K.; Rinta-Antila, S.; Schaefer, D.; Scheidenberger, C.; Takechi, M.; Tanaka, Y. K.; Winfield, J. S.; Yavor, M. I.

2013-01-01

At the FRS Ion Catcher at GSI, projectile and fission fragments are produced at relativistic energies, separated in-flight, range-focused, slowed down and thermalized in a cryogenic stopping cell. A multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS) is used to perform direct mass

On recoil energy dependent void swelling in pure copper: Theoretical treatment

International Nuclear Information System (INIS)

Golubov, S.I.; Singh, B.N.; Trinkaus, H.

2000-06-01

Over the years, an enormous amount of experimental results have been reported on damage accumulation (e.g. void swelling) in metals and alloys irradiated under vastly different recoil energy conditions. Unfortunately, however, very little is known either experimentally or theoretically about the effect of recoil energy on damage accumulation. Recently, dedicated irradiation experiments using 2.5 MeV electrons, 3.0 MeV protons and fission neutrons have been carried out to determine the effect of recoil energy on the damage accumulation behaviour in pure copper and the results have been reported in Part I of this paper (Singh, Eldrup, Horsewell, Ehrhart and Dworschak 2000). The present paper attempts to provide a theoretical framework within which the effect of recoil energy on damage accumulation behaviour can be understood. The damage accumulation under Frenkel pair production (e.g. 2.5 MeV electron) has been treated in terms of the standard rate theory (SRT) model whereas the evolution of the defect microstructure under cascade damage conditions (e.g. 3.0 MeV protons and fission neutrons) has been calculated within the framework of the production bias model (PBM). Theoretical results, in agreement with experimental results, show that the damage accumulation behaviour is very sensitive to recoil energy and under cascade damage conditions can be treated only within the framework of the PBM. The intracascade clustering of self-interstitial atoms (SIAs) and the properties of SIA clusters such as one-dimensional diffusional transport and thermal stability are found to be the main reasons for the recoil energy dependent vacancy supersaturation. The vacancy supersaturation is the main driving force for the void nucleation and void swelling. In the case of Frenkel pair production, the experimental results are found to be consistent with the SRT model with a dislocation bias value of 2 %. (au)

Measurement of Nuclear Recoils in the CDMS II Dark Matter Search

Energy Technology Data Exchange (ETDEWEB)

Fallows, Scott Mathew [Univ. of Minnesota, Minneapolis, MN (United States)

2014-12-01

The Cryogenic Dark Matter Search (CDMS) experiment is designed to directly detect elastic scatters of weakly-interacting massive dark matter particles (WIMPs), on target nuclei in semiconductor crystals composed of Si and Ge. These scatters would occur very rarely, in an overwhelming background composed primarily of electron recoils from photons and electrons, as well as a smaller but non-negligible background of WIMP-like nuclear recoils from neutrons. The CDMS II generation of detectors simultaneously measure ionization and athermal phonon signals from each scatter, allowing discrimination against virtually all electron recoils in the detector bulk. Pulse-shape timing analysis allows discrimination against nearly all remaining electron recoils taking place near detector surfaces. Along with carefully limited neutron backgrounds, this experimental program allowed for \\background- free" operation of CDMS II at Soudan, with less than one background event expected in each WIMP-search analysis. As a result, exclusionary upper-limits on WIMP-nucleon interaction cross section were placed over a wide range of candidate WIMP masses, ruling out large new regions of parameter space.

Recoil-distance lifetime measurements of the ground-state band in 164Dy, 170Er, and 174Yb

International Nuclear Information System (INIS)

Sie, S.H.; Gebbie, D.W.

1977-06-01

Mean-lives of the 4 + , 6 + and 8 + levels of the ground-state band in 164 Dy, 170 Er and 174 Yb have been measured by the recoil-distance technique following multiple Coulomb excitation with 32 S projectiles of energy 120-140 MeV. The gamma-rays were detected in coincidence with backscattered particles. The results are compared with theoretical predictions of the adiabatic rotor model. The 6 + and 8 + lifetimes in 164 Dy are found to correspond to a slight reduction in B(E2) values over the rotational model prediction, while for for the 4 + state a 12% reduction was observed. In 170 Er and 174 Yb the lifetimes are consistent with rotational model predictions with a slight enhancement of B(E2) values at higher spins. Comparison with other results from Doppler broadened lineshape analysis confirms the need to adjust the electronic stopping powers of Northcliffe and Schilling in the lineshape calculations. (Author)

Synchrotron-radiation experiments with recoil ions

International Nuclear Information System (INIS)

Levin, J.C.

1989-01-01

Studies of atoms, ions and molecules with synchrotron radiation have generally focused on measurements of properties of the electrons ejected during, or after, the photoionization process. Much can also be learned, however, about the atomic or molecular relaxation process by studies of the residual ions or molecular fragments following inner-shell photoionization. Measurements are reported of mean kinetic energies of highly charged argon, krypton, and xenon recoil ions produced by vacancy cascades following inner-shell photoionization using white and monochromatic synchrotron x radiation. Energies are much lower than for the same charge-state ions produced by charged-particle impact. The results may be applicable to design of future angle-resolved ion-atom collision experiments. Photoion charge distributions are presented and compared with other measurements and calculations. Related experiments with synchrotron-radiation produced recoil ion, including photoionization of stored ions and measurement of shakeoff in near-threshold excitation, are briefly discussed. 24 refs., 6 figs., 1 tab

77 FR 44572 - Second Fishing Capacity Reduction Program for the Longline Catcher Processor Subsector of the...

Science.gov (United States)

2012-07-30

... long-line catcher processors harvesting non-pollock groundfish were required to pay and forward a fee... reports (4 hours), and tendering fish buyer/fish seller reports when a person fails either to pay or to... discrepancy in the name appearing on LLP Licenses and other documents was material). (2) [Reserved] (e...

Molecular frame and recoil frame angular distributions in dissociative photoionization of small molecules

International Nuclear Information System (INIS)

Lucchese, R R; Carey, R; Elkharrat, C; Houver, J C; Dowek, D

2008-01-01

Photoelectron angular distributions in the dipole approximation can be written with respect to several different reference frames. A brief review of the molecular frame and recoil frame are given. Experimentally, one approach for obtaining such angular distributions is through angle-resolved coincidence measurements of dissociative ionization. If the system dissociates into two heavy fragments, then the recoil frame angular distribution can be measured. Computed molecular frame and recoil frame photoelectron angular distributions are compared to experimental data for the Cl 2p ionization of CH 3 Cl.

A recoil resilient lumen support, design, fabrication and mechanical evaluation

Science.gov (United States)

Mehdizadeh, Arash; Ali, Mohamed Sultan Mohamed; Takahata, Kenichi; Al-Sarawi, Said; Abbott, Derek

2013-06-01

Stents are artificial implants that provide scaffolding to a cavity inside the body. This paper presents a new luminal device for reducing the mechanical failure of stents due to recoil, which is one of the most important issues in stenting. This device, which we call a recoil-resilient ring (RRR), is utilized standalone or potentially integrated with existing stents to address the problem of recoil. The proposed structure aims to minimize the need for high-pressure overexpansion that can induce intra-luminal trauma and excess growth of vascular tissue causing later restenosis. The RRR is an overlapped open ring with asymmetrical sawtooth structures that are intermeshed. These teeth can slide on top of each other, while the ring is radially expanded, but interlock step-by-step so as to keep the final expanded state against compressional forces that normally cause recoil. The RRRs thus deliver balloon expandability and, when integrated with a stent, bring both radial rigidity and longitudinal flexibility to the stent. The design of the RRR is investigated through finite element analysis (FEA), and then the devices are fabricated using micro-electro-discharge machining of 200-µm-thick Nitinol sheet. The standalone RRR is balloon expandable in vitro by 5-7 Atm in pressure, which is well within the recommended in vivo pressure ranges for stenting procedures. FEA compression tests indicate 13× less reduction of the cross-sectional area of the RRR compared with a typical stainless steel stent. These results also show perfect elastic recovery of the RRR after removal of the pressure compared to the remaining plastic deformations of the stainless steel stent. On the other hand, experimental loading tests show that the fabricated RRRs have 2.8× radial stiffness compared to a two-column section of a commercial stent while exhibiting comparable elastic recovery. Furthermore, testing of in vitro expansion in a mock artery tube shows around 2.9% recoil, approximately 5-11�

A recoil resilient lumen support, design, fabrication and mechanical evaluation

International Nuclear Information System (INIS)

Mehdizadeh, Arash; Al-Sarawi, Said; Abbott, Derek; Ali, Mohamed Sultan Mohamed; Takahata, Kenichi

2013-01-01

Stents are artificial implants that provide scaffolding to a cavity inside the body. This paper presents a new luminal device for reducing the mechanical failure of stents due to recoil, which is one of the most important issues in stenting. This device, which we call a recoil-resilient ring (RRR), is utilized standalone or potentially integrated with existing stents to address the problem of recoil. The proposed structure aims to minimize the need for high-pressure overexpansion that can induce intra-luminal trauma and excess growth of vascular tissue causing later restenosis. The RRR is an overlapped open ring with asymmetrical sawtooth structures that are intermeshed. These teeth can slide on top of each other, while the ring is radially expanded, but interlock step-by-step so as to keep the final expanded state against compressional forces that normally cause recoil. The RRRs thus deliver balloon expandability and, when integrated with a stent, bring both radial rigidity and longitudinal flexibility to the stent. The design of the RRR is investigated through finite element analysis (FEA), and then the devices are fabricated using micro-electro-discharge machining of 200-µm-thick Nitinol sheet. The standalone RRR is balloon expandable in vitro by 5–7 Atm in pressure, which is well within the recommended in vivo pressure ranges for stenting procedures. FEA compression tests indicate 13× less reduction of the cross-sectional area of the RRR compared with a typical stainless steel stent. These results also show perfect elastic recovery of the RRR after removal of the pressure compared to the remaining plastic deformations of the stainless steel stent. On the other hand, experimental loading tests show that the fabricated RRRs have 2.8× radial stiffness compared to a two-column section of a commercial stent while exhibiting comparable elastic recovery. Furthermore, testing of in vitro expansion in a mock artery tube shows around 2.9% recoil, approximately 5�

Recoiling Black Holes: Electromagnetic Signatures, Candidates, and Astrophysical Implications

Directory of Open Access Journals (Sweden)

S. Komossa

2012-01-01

Full Text Available Supermassive black holes (SMBHs may not always reside right at the centers of their host galaxies. This is a prediction of numerical relativity simulations, which imply that the newly formed single SMBH, after binary coalescence in a galaxy merger, can receive kick velocities up to several 1000 km/s due to anisotropic emission of gravitational waves. Long-lived oscillations of the SMBHs in galaxy cores, and in rare cases even SMBH ejections from their host galaxies, are the consequence. Observationally, accreting recoiling SMBHs would appear as quasars spatially and/or kinematically offset from their host galaxies. The presence of the “kicks” has a wide range of astrophysical implications which only now are beginning to be explored, including consequences for black hole and galaxy assembly at the epoch of structure formation, black hole feeding, and unified models of active galactic nuclei (AGN. Here, we review the observational signatures of recoiling SMBHs and the properties of the first candidates which have emerged, including follow-up studies of the candidate recoiling SMBH of SDSSJ092712.65+294344.0.

Experimental study on two-phase flow natural circulation in a core catcher cooling channel for EU-APR1400 using air-water system

Energy Technology Data Exchange (ETDEWEB)

Song, Ki Won [Division of Advanced Nuclear Engineering, POSTECH, Pohang 790-784 (Korea, Republic of); Korea Atomic Energy Research Institute, Daejeon 34057 (Korea, Republic of); Nguyen, Thanh Hung [School of Nuclear Engineering, Purdue University, West Lafayette, IN 47906 (United States); Ha, Kwang Soon; Kim, Hwan Yeol; Song, Jinho [Korea Atomic Energy Research Institute, Daejeon 34057 (Korea, Republic of); Park, Hyun Sun [Division of Advanced Nuclear Engineering, POSTECH, Pohang 790-784 (Korea, Republic of); Revankar, Shripad T., E-mail: shripad@postech.ac.kr [Division of Advanced Nuclear Engineering, POSTECH, Pohang 790-784 (Korea, Republic of); School of Nuclear Engineering, Purdue University, West Lafayette, IN 47906 (United States); Kim, Moo Hwan [Division of Advanced Nuclear Engineering, POSTECH, Pohang 790-784 (Korea, Republic of); Korea Institute of Nuclear Safety, Daejeon 305-338 (Korea, Republic of)

2017-05-15

Highlights: • Two-phase flow regimes and transition behavior were observed in the coolant channel. • Test were conducted for natural circulation with air-water. • Data were obtained on flow regime, void fraction, flow rates and re-wetting time. • The data were related to a cooling capability of core catcher system. - Abstract: Ex-vessel core catcher cooling system driven by natural circulation is designed using a full scaled air-water system. A transparent half symmetric section of a core catcher coolant channel of a pressurized water reactor was designed with instrumentations for local void fraction measurement and flow visualization. Two designs of air-water top separator water tanks are studied including one with modified ‘super-step’ design which prevents gas entrainment into down-comer. In the experiment air flow rates are set corresponding to steam generation rate for given corium decay power. Measurements of natural circulation flow rate, spatial local void fraction distribution and re-wetting time near the top wall are carried out for various air flow rates which simulate boiling-induced vapor generation. Since heat transfer and critical heat flux are strongly dependent on the water mass flow rate and development of two-phase flow on the heated wall, knowledge of two-phase flow characteristics in the coolant channel is essential. Results on flow visualization showing two phase flow structure specifically near the high void accumulation regions, local void profiles, rewetting time, and natural circulation flow rate are presented for various air flow rates that simulate corium power levels. The data are useful in assessing the cooling capability of and safety of the core catcher system.

Limitations to depth resolution in high-energy, heavy-ion elastic recoil detection analysis

International Nuclear Information System (INIS)

Elliman, R.G.; Palmer, G.R.; Ophel, T.R.; Timmers, H.

1998-01-01

The depth resolution of heavy-ion elastic recoil detection analysis was examined for Al and Co thin films ranging in thickness from 100 to 400 nm. Measurements were performed with 154 MeV Au ions as the incident beam, and recoils were detected using a gas ionisation detector. Energy spectra were extracted for the Al and Co recoils and the depth resolution determined as a function of film thickness from the width of the high- and low- energy edges. These results were compared with theoretical estimates calculated using the computer program DEPTH. (authors)

Elastic recoil detection analysis of hydrogen in polymers

Energy Technology Data Exchange (ETDEWEB)

Winzell, T.R.H.; Whitlow, H.J. [Lund Univ. (Sweden); Bubb, I.F.; Short, R.; Johnston, P.N. [Royal Melbourne Inst. of Tech., VIC (Australia)

1996-12-31

Elastic recoil detection analysis (ERDA) of hydrogen in thick polymeric films has been performed using 2.5 MeV He{sup 2+} ions from the tandem accelerator at the Royal Melbourne Institute of Technology. The technique enables the use of the same equipment as in Rutherford backscattering analysis, but instead of detecting the incident backscattered ion, the lighter recoiled ion is detected at a small forward angle. The purpose of this work is to investigate how selected polymers react when irradiated by helium ions. The polymers are to be evaluated for their suitability as reference standards for hydrogen depth profiling. Films investigated were Du Pont`s Kapton and Mylar, and polystyrene. 11 refs., 3 figs.

Elastic recoil detection analysis of hydrogen in polymers

Energy Technology Data Exchange (ETDEWEB)

Winzell, T R.H.; Whitlow, H J [Lund Univ. (Sweden); Bubb, I F; Short, R; Johnston, P N [Royal Melbourne Inst. of Tech., VIC (Australia)

1997-12-31

Elastic recoil detection analysis (ERDA) of hydrogen in thick polymeric films has been performed using 2.5 MeV He{sup 2+} ions from the tandem accelerator at the Royal Melbourne Institute of Technology. The technique enables the use of the same equipment as in Rutherford backscattering analysis, but instead of detecting the incident backscattered ion, the lighter recoiled ion is detected at a small forward angle. The purpose of this work is to investigate how selected polymers react when irradiated by helium ions. The polymers are to be evaluated for their suitability as reference standards for hydrogen depth profiling. Films investigated were Du Pont`s Kapton and Mylar, and polystyrene. 11 refs., 3 figs.

77 FR 58775 - Second Fishing Capacity Reduction Program for the Longline Catcher Processor Subsector of the...

Science.gov (United States)

2012-09-24

... long-line catcher processors harvesting non-pollock groundfish were required to pay and forward a fee... seller reports when a person fails either to pay or to collect the loan repayment fee (2 hours). These... Act, or whether a discrepancy in the name appearing on LLP Licenses and other documents was material...

76 FR 39794 - Fisheries of the Economic Exclusive Zone Off Alaska; Shallow-Water Species Fishery by Catcher...

Science.gov (United States)

2011-07-07

.... 101126522-0640-02] RIN 0648-XA539 Fisheries of the Economic Exclusive Zone Off Alaska; Shallow- Water...; closure. SUMMARY: NMFS is prohibiting directed fishing for species that comprise the shallow-water species... species catch (PSC) sideboard limit specified for the shallow-water species fishery for catcher/processors...

Multivariate techniques of analysis for ToF-E recoil spectrometry data

Energy Technology Data Exchange (ETDEWEB)

Whitlow, H.J.; Bouanani, M.E.; Persson, L.; Hult, M.; Jonsson, P.; Johnston, P.N. [Lund Institute of Technology, Solvegatan, (Sweden), Department of Nuclear Physics; Andersson, M. [Uppsala Univ. (Sweden). Dept. of Organic Chemistry; Ostling, M.; Zaring, C. [Royal institute of Technology, Electrum, Kista, (Sweden), Department of Electronics; Johnston, P.N.; Bubb, I.F.; Walker, B.R.; Stannard, W.B. [Royal Melbourne Inst. of Tech., VIC (Australia); Cohen, D.D.; Dytlewski, N. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

1996-12-31

Multivariate statistical methods are being developed by the Australian -Swedish Recoil Spectrometry Collaboration for quantitative analysis of the wealth of information in Time of Flight (ToF) and energy dispersive Recoil Spectrometry. An overview is presented of progress made in the use of multivariate techniques for energy calibration, separation of mass-overlapped signals and simulation of ToF-E data. 6 refs., 5 figs.

Multivariate techniques of analysis for ToF-E recoil spectrometry data

Energy Technology Data Exchange (ETDEWEB)

Whitlow, H J; Bouanani, M E; Persson, L; Hult, M; Jonsson, P; Johnston, P N [Lund Institute of Technology, Solvegatan, (Sweden), Department of Nuclear Physics; Andersson, M [Uppsala Univ. (Sweden). Dept. of Organic Chemistry; Ostling, M; Zaring, C [Royal institute of Technology, Electrum, Kista, (Sweden), Department of Electronics; Johnston, P N; Bubb, I F; Walker, B R; Stannard, W B [Royal Melbourne Inst. of Tech., VIC (Australia); Cohen, D D; Dytlewski, N [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

1997-12-31

Multivariate statistical methods are being developed by the Australian -Swedish Recoil Spectrometry Collaboration for quantitative analysis of the wealth of information in Time of Flight (ToF) and energy dispersive Recoil Spectrometry. An overview is presented of progress made in the use of multivariate techniques for energy calibration, separation of mass-overlapped signals and simulation of ToF-E data. 6 refs., 5 figs.

A new recoil filter for {gamma}-detector arrays

Energy Technology Data Exchange (ETDEWEB)

Heese, J; Lahmer, W; Maier, K H [Hahn-Meitner-Institut Berlin GmbH (Germany); Janicki, M; Meczynski, W; Styczen, J [Institute of Nuclear Physics, Cracow (Poland)

1992-08-01

A considerable improvement of gamma spectra recorded in heavy ion induced fusion evaporation residues can be achieved when gamma rays are detected in coincidence with the recoiling evaporations residues. This coincidence suppresses gamma rays from fission processes, Coulombic excitation, and reactions with target contaminations, and therefore cleans gamma spectra and improves the peak to background ratio. A sturdy detector for evaporation residues has been designed as an additional detector for the OSIRIS spectrometer. The recoil filter consists of two rings of six and twelve detector elements. In each detector element, nuclei hitting a thin Mylar foil produce secondary electrons, which are electrostatically accelerated and focussed onto a thin plastic scintillator. Recoiling evaporation residues are discriminated from other reaction products and scattered beam by the pulse height of the scintillation signal and time of flight. The detector signal is fast enough to allow the detection of an evaporation residue even if the scattered beam hits the detector first. In-beam experiment were performed with the reactions {sup 40}Ar+{sup 124}Sn, {sup 40}Ar+{sup 152}Sm at 185 MeV beam energy, and {sup 36}Ar+{sup 154,156}Gd at 175 MeV. In the latter two cases, fission amount to 50-75% of the total fusion cross section. 10 refs., 4 figs.

Gravitational recoil from binary black hole mergers: The close-limit approximation

International Nuclear Information System (INIS)

Sopuerta, Carlos F.; Yunes, Nicolas; Laguna, Pablo

2006-01-01

The coalescence of a binary black hole system is one of the main sources of gravitational waves that present and future detectors will study. Apart from the energy and angular momentum that these waves carry, for unequal-mass binaries there is also a net flux of linear momentum that implies a recoil velocity of the resulting final black hole in the opposite direction. Due to the relevance of this phenomenon in astrophysics, in particular, for galaxy merger scenarios, there have been several attempts to estimate the magnitude of this velocity. Since the main contribution to the recoil comes from the last orbit and plunge, an approximation valid at the last stage of coalescence is well motivated for this type of calculation. In this paper, we present a computation of the recoil velocity based on the close-limit approximation scheme, which gives excellent results for head-on and grazing collisions of black holes when compared to full numerical relativistic calculations. We obtain a maximum recoil velocity of ∼57 km/s for a symmetric mass ratio η=M 1 M 2 /(M 1 +M 2 ) 2 ∼0.19 and an initial proper separation of 4M, where M is the total Arnowitt-Deser-Misner (ADM) mass of the system. This separation is the maximum at which the close-limit approximation is expected to provide accurate results. Therefore, it cannot account for the contributions due to inspiral and initial merger. If we supplement this estimate with post-Newtonian (PN) calculations up to the innermost stable circular orbit, we obtain a lower bound for the recoil velocity, with a maximum around 80 km/s. This is a lower bound because it neglects the initial merger phase. We can however obtain a rough estimate by using PN methods or the close-limit approximation. Since both methods are known to overestimate the amount of radiation, we obtain in this way an upper bound for the recoil with maxima in the range of 214-240 km/s. We also provide nonlinear fits to these estimated upper and lower bounds. These

Exclusive {rho}{sup 0} production measured with the HERMES recoil detector

Energy Technology Data Exchange (ETDEWEB)

Perez Benito, Roberto Francisco

2010-12-15

The Hermes experiment (HERa MEasurement of Spin) at Desy was designed to study the spin structure of the nucleon in semi-inclusive deep inelastic scattering. The internal structure of the nucleon has been investigated in detail and it has been measured that the intrinsic quark spin contribution is only about 30% of the total spin of the nucleon. A formalism to describe the internal structure of the nucleon called Generalised Patron Distributions (GPDs) was developed recently to understand the fundamental structure of the nucleon. These GPDs can be accessed by the measurement of hard exclusive reactions and hard exclusive processes that can be understood in terms of GPDs. The accumulated Hermes data offer access to GPDs in different combinations of beam charge and beam and target helicity asymmetries. To improve exclusivity and to enhance the resolution of kinematic variables to study hard exclusive processes which provide access to the GPDs and hence to the orbital angular momentum of the quarks, in January 2006 a Recoil Detector was installed that surrounded the internal gas target of the Hermes experiment. The Hermes Recoil Detector consisted of three components: a silicon strip detector inside the vacuum, a scintillating fiber tracker and the photon detector. All three detectors were located inside a solenoidal magnet which provided a 1T longitudinal magnetic field. The Recoil Detector improves the selection of exclusive events by a direct measurement of the momentum and track position of the recoiling particle as well as by rejecting non-exclusive background. This detector was an ideal novel tool to combine energy and position measurements for charged particles in a momentum range of 0.1 to 1.4 GeV/c. The Recoil Detector was fully commissioned and operating. Data was taken continuously until the final Hera shutdown in July of 2007. In this thesis we report on the performance of the Recoil Detector and more specifically about the scintillating fiber tracker

Recoiling D-branes

International Nuclear Information System (INIS)

Nakamura, Shin

2005-01-01

We propose a new method to describe a recoiling D-brane that is elastically scattered by closed strings in the nonrelativistic region. We utilize the low-energy effective field theory on the worldvolume of the D-brane, and the velocity of the D-brane is described by the time derivative of the expectation values of the massless scalar fields on the worldvolume. The effects of the closed strings are represented by a source term for the massless fields in this method. The momentum conservation condition between the closed strings and the D-brane is derived up to the relative sign of the momentum of the D-brane

Remote recoil: a new wave mean interaction effect

Science.gov (United States)

Bühler, Oliver; McIntyre, Michael E.

2003-10-01

We present a theoretical study of a fundamentally new wave mean or wave vortex interaction effect able to force persistent, cumulative change in mean flows in the absence of wave breaking or other kinds of wave dissipation. It is associated with the refraction of non-dissipating waves by inhomogeneous mean (vortical) flows. The effect is studied in detail in the simplest relevant model, the two-dimensional compressible flow equations with a generic polytropic equation of state. This includes the usual shallow-water equations as a special case. The refraction of a narrow, slowly varying wavetrain of small-amplitude gravity or sound waves obliquely incident on a single weak (low Froude or Mach number) vortex is studied in detail. It is shown that, concomitant with the changes in the waves' pseudomomentum due to the refraction, there is an equal and opposite recoil force that is felt, in effect, by the vortex core. This effective force is called a ‘remote recoil’ to stress that there is no need for the vortex core and wavetrain to overlap in physical space. There is an accompanying ‘far-field recoil’ that is still more remote, as in classical vortex-impulse problems. The remote-recoil effects are studied perturbatively using the wave amplitude and vortex weakness as small parameters. The nature of the remote recoil is demonstrated in various set-ups with wavetrains of finite or infinite length. The effective recoil force {bm R}_V on the vortex core is given by an expression resembling the classical Magnus force felt by moving cylinders with circulation. In the case of wavetrains of infinite length, an explicit formula for the scattering angle theta_* of waves passing a vortex at a distance is derived correct to second order in Froude or Mach number. To this order {bm R}_V {~} theta_*. The formula is cross-checked against numerical integrations of the ray-tracing equations. This work is part of an ongoing study of internal-gravity-wave dynamics in the

Heavy ion recoil spectrometry of SixGe1-x thin films

International Nuclear Information System (INIS)

Walker, S.R.; Johnston, P.N.; Bubb, I.F.; Cohen, D.D.; Dytlewski, N.; Hult, M.; Whitlow, H.J.; Zaring, C.; Oestling, M.

1993-01-01

Mass and energy dispersive recoil spectrometry employing 77 MeV 127 I ions from ANTARES (FN Tandem) facility at Lucas Heights has been used to examine the isotopic composition of samples of Si x Ge 1-x grown at the Australian National University by Electron Beam Evaporation (EBE). The recoiling target nuclei were analysed by a Time Of Flight and Energy (TOF-E) detector telescope composed of two timing pickoff detectors and a surface barrier (energy) detector. From the time of flight and energy, the ion mass can be determined and individual depth distributions for each element can be obtained. Recoil spectrometry has shown the presence of oxygen in the Si x Ge 1-x layer and has enabled the separate determination of energy spectra for individual elements. 9 refs., 3 figs

75 FR 38938 - Fisheries of the Economic Exclusive Zone Off Alaska; Shallow-Water Species Fishery by Catcher...

Science.gov (United States)

2010-07-07

.... 0910131362-0087-02] RIN 0648-XX31 Fisheries of the Economic Exclusive Zone Off Alaska; Shallow- Water Species...: NMFS is prohibiting directed fishing for species that comprise the shallow-water species fishery for... (PSC) sideboard limit specified for the shallow-water species fishery for catcher/processors subject to...

Recoil 18F-chemistry in fluoroalkanes

International Nuclear Information System (INIS)

Linde, K.D. van der.

1982-01-01

This thesis describes the study of the chemical reactions of recoil 18 F-atoms in gaseous fluoromethanes and fluoroethanes. A brief survey of the organic hot atom chemistry is given in Chapter I. Chapter II deals with the experimental procedures used in this investigation. The irradiation facilities, the vapour phase radio-chromatography and the identification, including the synthesis of some fluorocarbons, are described in detail. Chapter III consists of a study on the applicability of perfluoropropene, C 3 F 6 , as scavenger for thermal 18 F-atoms and radicals. Chapters IV, V, VI and VII deal with 18 F-recoil chemistry in gaseous fluoroethanes, using H 2 S as scavenger. Chapter VIII is a short discussion on the hot 18 F-atom based production of 18 F-labeled organic compounds via decay of the intermediate 18 Ne. A target system is proposed for production of this isotope in high energy and ultra high flux particle beams, which possibly would become available in fast breeders and fusion reactors. (Auth.)

Measurements of the ballistic-phonon component resulting from nuclear and electron recoils in crystalline silicon

International Nuclear Information System (INIS)

Lee, A.T.; Cabrera, B.; Dougherty, B.L.; Penn, M.J.; Pronko, J.G.; Tamura, S.

1996-01-01

We present measurements of the ballistic-phonon component resulting from nuclear and electron recoils in silicon at ∼380 mK. The detectors used for these experiments consist of a 300-μm-thick monocrystal of silicon instrumented with superconducting titanium transition-edge sensors. These sensors detect the initial wavefront of athermal phonons and give a pulse height that is sensitive to changes in surface-energy density resulting from the focusing of ballistic phonons. Nuclear recoils were generated by neutron bombardment of the detector. A Van de Graaff proton accelerator and a thick 7 Li target were used. Pulse-height spectra were compared for neutron, x-ray, and γ-ray events. A previous analysis of this data set found evidence for an increase in the ballistic-phonon component for nuclear recoils compared to electron recoils at a 95% confidence level. An improved understanding of the detector response has led to a change in the result. In the present analysis, the data are consistent with no increase at the 68% confidence level. This change stems from an increase in the uncertainty of the result rather than a significant change in the central value. The increase in ballistic phonon energy for nuclear recoils compared to electron recoils as a fraction of the total phonon energy (for equal total phonon energy events) was found to be 0.024 +0.041 -0.055 (68% confidence level). This result sets a limit of 11.6% (95% confidence level) on the ballistic phonon enhancement for nuclear recoils predicted by open-quote open-quote hot spot close-quote close-quote and electron-hole droplet models, which is the most stringent to date. To measure the ballistic-phonon component resulting from electron recoils, the pulse height as a function of event depth was compared to that of phonon simulations. (Abstract Truncated)

In-beam electron spectrometer used in conjunction with a gas-filled recoil separator

International Nuclear Information System (INIS)

Kankaanpaeae, H.; Butler, P.A.; Greenlees, P.T.; Bastin, J.E.; Herzberg, R.D.; Humphreys, R.D.; Jones, G.D.; Jones, P.; Julin, R.; Keenan, A.; Kettunen, H.; Leino, M.; Miettinen, L.; Page, T.; Rahkila, P.; Scholey, C.; Uusitalo, J.

2004-01-01

The conversion-electron spectrometer SACRED has been redesigned for use in conjunction with the RITU gas-filled recoil separator. The system allows in-beam recoil-decay-tagging (RDT) measurements of internal conversion electrons. The performance of the system using standard sources and in-beam is described

catcher: A Software Program to Detect Answer Copying in Multiple-Choice Tests Based on Nominal Response Model

Science.gov (United States)

Kalender, Ilker

2012-01-01

catcher is a software program designed to compute the [omega] index, a common statistical index for the identification of collusions (cheating) among examinees taking an educational or psychological test. It requires (a) responses and (b) ability estimations of individuals, and (c) item parameters to make computations and outputs the results of…

New developments of the recoil distance doppler-shift method

Energy Technology Data Exchange (ETDEWEB)

Fransen, Christoph; Blazhev, Andrey; Braunroth, Thomas; Dewald, Alfred; Goldkuhle, Alina; Jolie, Jan; Litzinger, Julia; Mueller-Gatermann, Claus; Woelk, Dorothea; Zell, Karl-Oskar [Institut fuer Kernphysik, Universitaet zu Koeln (Germany)

2016-07-01

The recoil distance Doppler-shift (RDDS) method is a very valuable technique for measuring lifetimes of excited nuclear states in the picosecond range to deduce absolute transition strengths between nuclear excitations independent on the reaction mechanism. Dedicated plunger devices were built by our group for measurements with this method for a broad range of beam energies ranging from few MeV/u up to relativistic energies of the order of 100 MeV/u. Those were designed to match the constraints defined by state-of-the art γ-ray spectrometers like AGATA, Galileo, Gammasphere. Here we give an overview about recent experiments of our group to determine transition strengths from level lifetimes in exotic nuclei where also recoil separators or mass spectrographs were used for an identification of the recoiling reaction products. The aim is to learn about phenomena like shape phase coexistence in exotic regions and the evolution of the shell structure far from the valley of stability. We also review new plunger devices that are developed by our group for future experimental campaigns with stable and radioactive beams in different energy regimes, e.g., a plunger for HIE-ISOLDE.

Thermal annealing of recoil 56Mn in strontium permanganate under (n,γ) process

International Nuclear Information System (INIS)

Mishra, Shuddhodan P.; Vijaya

2002-01-01

Chemical stabilization of recoil 56 Mn in strontium permanganate (hydrous and anhydrous) has been investigated with a special reference to pre-and post-activation thermal annealing treatments. The retention of 56 Mn in neutron irradiated strontium permanganate showed significant variation on thermal annealing in both pre-and post-activation heated target. The recoil re-entry process obeys simple first order kinetics and the activation energy deduced for thermal annealing process is very low as computed by classical Arrhenius plots. The results observed are discussed in the light of existing ideas for understanding the recoil stabilization mechanism of parent reformation and the nature of precursors in permanganates. (author)

INS gas-filled recoil isotope separator

International Nuclear Information System (INIS)

Miyatake, M.; Nomura, T.; Kawakami, H.

1986-09-01

The characteristics and performance of a small sized gas-filled recoil isotope separator recently made at INS are described. The total efficiency and the ΔBρ/Bρ values have been measured using low velocity 16 O, 40 Ar and 68 As ions and found to be 10 and 5 %, respectively. The Z-dependence of the mean charge is discussed. (author)

Recoil-ion momentum spectroscopy

International Nuclear Information System (INIS)

Ullrich, J.; Moshammer, R.; Doerner, R.; Jagutzki, O.; Mergel, V.; Schmidt-Boecking, H.; Spielberger, L.

1996-10-01

High-resolution recoil-ion momentum spectroscopy (RIMS) is a novel technique to determine the charge state and the complete final momentum vector P R of a recoiling target ion emerging from an ionising collision of an atom with any kind of radiation. It offers a unique combination of superior momentum resolution in all three spatial directions of ΔP R = 0.07 a.u. with a large detection solid angle of ΔΩ R /4π≥ 98%. Recently, low-energy electron analysers based on rigorously new concepts and reaching similar specifications were successfully integrated into RIM spectrometers yielding so-called ''reaction microscopes''. Exploiting these techniques, a large variety of atomic reactions for ion, electron, photon and antiproton impact have been explored in unprecedented detail and completeness. Among them first kinematically complete experiments on electron capture, single and double ionisation in ion-atom collisions at projectile energies between 5 keV and 1.4 GeV. Double photoionisation of He has been investigated at energies E γ close to the threshold (E γ = 80 eV) up to E γ = 58 keV. At E γ >8 keV the contributions to double ionisation after photoabsorption and Compton scattering were kinematically separated for the first time. These and many other results will be reviewed in this article. In addition, the experimental technique is described in some detail and emphasis is given to envisage the rich future potential of the method in various fields of atomic collision physics with atoms, molecules and clusters. (orig.)

Recoil detector test for the day-one experiment at HESR

Energy Technology Data Exchange (ETDEWEB)

Hu, Qiang [Institute of Modern Physics, CAS, 730000 Lanzhou (China); Forschungszentrum Juelich, 52425 Juelich (Germany); Xu, Huagen; Ritman, James [Forschungszentrum Juelich, 52425 Juelich (Germany)

2013-07-01

The proposed day-one experiment at HESR is a dedicated measurement of antiproton-proton elastic scattering. The aim of the day-one experiment is to determine the elastic differential parameters (total cross section σ{sub T}, the ratio of real to imaginary part of the forward scattering amplitude ρ, and the slope parameter B) by measuring a large range of 4-momentum transfer squared t (0.0008-0.1 GeV{sup 2}). The conceptual design of the day-one experiment is to measure the elastic scattered antiproton and recoil proton, by a tracking detector in the small polar angle range and by an energy detector near 90 , respectively. The recoil arm covers a maximum polar angle range from 71 to 90 and consists of two silicon strip detectors (76.8(length) x 50.0(width) x 1.0(thickness) mm{sup 3}) and two germanium detectors (80.4(length) x 50.0(width) x 5.0 (11.0) (thickness) mm{sup 3}). All detectors are single sided structure with 1.2 mm pitch. The silicon detectors will be used to detect recoil protons with energy up to about 12 MeV and the germanium detectors will be used to detect protons with energy from 12 MeV to 60 MeV. At present, one recoil arm is being constructed and the test for the detectors with radioactive sources is on-going. Preliminary test results indicate that all detectors are operational and work properly. The latest test results of these detectors are presented.

A scaling study of the natural circulation flow of the ex-vessel core catcher cooling system of a 1400MW PWR for designing a scale-down test facility

International Nuclear Information System (INIS)

Rhee, Bo. W.; Ha, K. S.; Park, R. J.; Song, J. H.

2012-01-01

A scaling study on the steady state natural circulation flow along the flow path of the ex-vessel core catcher cooling system of 1400MWe PWR is described. The scaling criteria for reproducing the same thermalhydraulic characteristics of the natural circulation flow as the prototype core catcher cooling system in the scale-down test facility is derived and the resulting natural circulation flow characteristics of the prototype and scale-down facility analyzed and compared. The purpose of this study is to apply the similarity law to the prototype EU-APR1400 core catcher cooling system and the model test facility of this prototype system and derive a relationship between the heating channel characteristics and the down-comer piping characteristics so as to determine the down-comer pipe size and the orifice size of the model test facility. As the geometry and the heating wall heat flux of the heating channel of the model test facility will be the same as those of the prototype core catcher cooling system except the width of the heating channel is reduced, the axial distribution of the coolant quality (or void fraction) is expected to resemble each other between the prototype and model facility. Thus using this fact, the down-comer piping design characteristics of the model facility can be determined from the relationship derived from the similarity law

Nuclear recoil scintillation and ionisation yields in liquid xenon from ZEPLIN-III data

Energy Technology Data Exchange (ETDEWEB)

Horn, M., E-mail: m.horn@imperial.ac.uk [High Energy Physics group, Blackett Laboratory, Imperial College London (United Kingdom); Belov, V.A.; Akimov, D.Yu. [Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Araujo, H.M. [High Energy Physics group, Blackett Laboratory, Imperial College London (United Kingdom); Barnes, E.J. [School of Physics and Astronomy, SUPA University of Edinburgh (United Kingdom); Burenkov, A.A. [Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Chepel, V. [LIP-Coimbra and Department of Physics of the University of Coimbra (Portugal); Currie, A. [High Energy Physics group, Blackett Laboratory, Imperial College London (United Kingdom); Edwards, B. [Particle Physics Department, STFC Rutherford Appleton Laboratory, Chilton (United Kingdom); Ghag, C.; Hollingsworth, A. [School of Physics and Astronomy, SUPA University of Edinburgh (United Kingdom); Kalmus, G.E. [Particle Physics Department, STFC Rutherford Appleton Laboratory, Chilton (United Kingdom); Kobyakin, A.S.; Kovalenko, A.G. [Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Lebedenko, V.N. [High Energy Physics group, Blackett Laboratory, Imperial College London (United Kingdom); Lindote, A. [LIP-Coimbra and Department of Physics of the University of Coimbra (Portugal); Particle Physics Department, STFC Rutherford Appleton Laboratory, Chilton (United Kingdom); Lopes, M.I. [LIP-Coimbra and Department of Physics of the University of Coimbra (Portugal); Luescher, R.; Majewski, P. [Particle Physics Department, STFC Rutherford Appleton Laboratory, Chilton (United Kingdom); Murphy, A.StJ. [School of Physics and Astronomy, SUPA University of Edinburgh (United Kingdom)

2011-11-24

Scintillation and ionisation yields for nuclear recoils in liquid xenon above 10 keV{sub nr} (nuclear recoil energy) are deduced from data acquired using broadband Am-Be neutron sources. The nuclear recoil data from several exposures to two sources were compared to detailed simulations. Energy-dependent scintillation and ionisation yields giving acceptable fits to the data were derived. Efficiency and resolution effects are treated using a light collection Monte Carlo, measured photomultiplier response profiles and hardware trigger studies. A gradual fall in scintillation yield below {approx}40 keV{sub nr} is found, together with a rising ionisation yield; both are in agreement with the latest independent measurements. The analysis method is applied to the most recent ZEPLIN-III data, acquired with a significantly upgraded detector and a precision-calibrated Am-Be source, as well as to the earlier data from the first run in 2008. A new method for deriving the recoil scintillation yield, which includes sub-threshold S1 events, is also presented which confirms the main analysis.

Laterally and longitudinally dispersive recoil mass separators

International Nuclear Information System (INIS)

Wollnik, H.

1987-01-01

Principles of laterally dispersive and time-of-flight mass separators are outlined. Special emphasis is given to separators for very energetic recoils for which electrostatic fields would be technologically impossible. The principle of energy isochronous time-of-flight mass separators is shown to be applicable to storage rings. (orig.)

Ex-vessel core catcher design requirements and preliminary concepts evaluation

International Nuclear Information System (INIS)

Friedland, A.J.; Tilbrook, R.W.

1974-01-01

As part of the overall study of the consequences of a hypothetical failure to scram following loss of pumping power, design requirements and preliminary concepts evaluation of an ex-vessel core catcher (EVCC) were performed. EVCC is the term applied to a class of devices whose primary objective is to provide a stable subcritical and coolable configuration within containment following a postulated accident in which it is assumed that core debris has penetrated the Reactor Vessel and Guard Vessel. Under these assumed conditions a set of functional requirements were developed for an EVCC and several concepts were evaluated. The studies were specifically directed toward the FFTF design considering the restraints imposed by the physical design and construction of the FFTF plant

The recoil proton polarization in πp elastic scattering

International Nuclear Information System (INIS)

Seftor, C.J.

1988-09-01

The polarization of the recoil proton for π + p and π - p elastic scattering has been measured for various angles at 547 MeV/c and 625 MeV/c by a collaboration involving The George Washington University; the University of California, Los Angeles; and Abilene Christian University. The experiment was performed at the P 3 East experimental area of the Los Alamos Meson Physics Facility. Beam intensities varied from 0.4 to 1.0 x 10 7 π - 's/sec and from 3.0 to 10.0 x 10 7 π + 's/sec. The beam spot size at the target was 1 cm in the horizontal direction by 2.5 cm in the vertical direction. A liquid-hydrogen target was used in a flask 5.7 cm in diameter and 10 cm high. The scattered pion and recoil proton were detected in coincidence using the Large Acceptance Spectrometer (LAS) to detect and momentum analyze the pions and the JANUS recoil proton polarimeter to detect and measure the polarization of the protons. Results from this experiment are compared with previous measurements of the polarization, with analyzing power data previously taken by this group, and to partial-wave analysis predictions. 12 refs., 53 figs., 18 tabs

Recoil distance lifetime measurements in 122,124Xe

Science.gov (United States)

Govil, I. M.; Kumar, A.; Iyer, H.; Li, H.; Garg, U.; Ghugre, S. S.; Johnson, T.; Kaczarowski, R.; Kharraja, B.; Naguleswaran, S.; Walpe, J. C.

1998-02-01

Lifetimes of the lower-excited states in 122,124Xe are measured using the recoil-distance Doppler-shift technique. The reactions 110Pd(16O,4n)122Xe and 110Pd(18O,4n)124Xe at a beam energy of 66 MeV were used for this experiment. The lifetimes of the 2+, 4+, 6+, and 8+ states of the ground state band were extracted using the computer code LIFETIME including the corrections due to the side feeding and the nuclear deorientation effects. The lifetime of the 2+ state in 122Xe agrees with the recoil distance method (RDM) measurements but for the 124Xe it does not agree with the RDM measurements but agrees with the Coulomb-excitation experiment. The measured B(E2) values for both the nuclei are compared with the standard algebraic and the multishell models.

Water droplet spreading and recoiling upon contact with thick-compact maltodextrin agglomerates.

Science.gov (United States)

Meraz-Torres, Lesvia Sofía; Quintanilla-Carvajal, María Ximena; Téllez-Medina, Darío I; Hernández-Sánchez, Humberto; Alamilla-Beltrán, Liliana; Gutiérrez-López, Gustavo F

2011-11-01

The food and pharmaceutical industries handle a number of compounds in the form of agglomerates which must be put into contact with water for rehydration purposes. In this work, liquid-solid interaction between water and maltodextrin thick-compact agglomerates was studied at different constituent particle sizes for two compression forces (75 and 225 MPa). Rapid droplet spreading was observed which was similar in radius to the expected one for ideal, flat surfaces. Contact angle determinations reported oscillations of this parameter throughout the experiments, being indicative of droplet recoiling on top of the agglomerate. Recoiling was more frequent in samples obtained at 225 MPa for agglomerate formation. Agglomerates obtained at 75 MPa exhibited more penetration of the water. Competition between dissolution of maltodextrin and penetration of the water was, probably, the main mechanism involved in droplet recoiling. Micrographs of the wetting marks were characterized by means of image analysis and the measurements suggested more symmetry of the wetting mark at higher compression force. Differences found in the evaluated parameters for agglomerates were mainly due to compaction force used. No significant effect of particle size in recoiling, penetration of water into the agglomerate, surface texture and symmetry was observed. Copyright © 2011 Society of Chemical Industry.

The Performance of the HRIBF Recoil Mass Spectrometry

International Nuclear Information System (INIS)

Ginter, T.N.

1998-01-01

The Recoil Mass Spectrometer (RMS) is a mass separator located at the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Laboratory. This paper describes the RMS, its performance, its detector systems, and discusses some experiments to illustrate its capabilities

RITA, a promising Monte Carlo code for recoil implantation

International Nuclear Information System (INIS)

Desalvo, A.; Rosa, R.

1982-01-01

A computer code previously set up to simulate ion penetration in amorphous solids has been extended to handle with recoil phenomena. Preliminary results are compared with existing experimental data. (author)

A Study of Nuclear Recoils in Liquid Argon Time Projection Chamber for the Direct Detection of WIMP Dark Matter

Energy Technology Data Exchange (ETDEWEB)

Cao, Huajie [Princeton Univ., NJ (United States)

2014-11-01

Robust results of WIMP direct detection experiments depend on rm understandings of nuclear recoils in the detector media. This thesis documents the most comprehensive study to date on nuclear recoils in liquid argon - a strong candidate for the next generation multi-ton scale WIMP detectors. This study investigates both the energy partition from nuclear recoil energy to secondary modes (scintillation and ionization) and the pulse shape characteristics of scintillation from nuclear recoils.

A study of nuclear recoil backgrounds in dark matter detectors

Science.gov (United States)

Westerdale, Shawn S.

Despite the great success of the Standard Model of particle physics, a preponderance of astrophysical evidence suggests that it cannot explain most of the matter in the universe. This so-called dark matter has eluded direct detection, though many theoretical extensions to the Standard Model predict the existence of particles with a mass on the 1-1000 GeV scale that interact only via the weak nuclear force. Particles in this class are referred to as Weakly Interacting Massive Particles (WIMPs), and their high masses and low scattering cross sections make them viable dark matter candidates. The rarity of WIMP-nucleus interactions makes them challenging to detect: any background can mask the signal they produce. Background rejection is therefore a major problem in dark matter detection. Many experiments greatly reduce their backgrounds by employing techniques to reject electron recoils. However, nuclear recoil backgrounds, which produce signals similar to what we expect from WIMPs, remain problematic. There are two primary sources of such backgrounds: surface backgrounds and neutron recoils. Surface backgrounds result from radioactivity on the inner surfaces of the detector sending recoiling nuclei into the detector. These backgrounds can be removed with fiducial cuts, at some cost to the experiment's exposure. In this dissertation we briefly discuss a novel technique for rejecting these events based on signals they make in the wavelength shifter coating on the inner surfaces of some detectors. Neutron recoils result from neutrons scattering off of nuclei in the detector. These backgrounds may produce a signal identical to what we expect from WIMPs and are extensively discussed here. We additionally present a new tool for calculating (alpha, n) yields in various materials. We introduce the concept of a neutron veto system designed to shield against, measure, and provide an anti-coincidence veto signal for background neutrons. We discuss the research and development

A Study of Nuclear Recoil Backgrounds in Dark Matter Detectors

Energy Technology Data Exchange (ETDEWEB)

Westerdale, Shawn S. [Princeton Univ., NJ (United States)

2016-01-01

Despite the great success of the Standard Model of particle physics, a preponderance of astrophysical evidence suggests that it cannot explain most of the matter in the universe. This so-called dark matter has eluded direct detection, though many theoretical extensions to the Standard Model predict the existence of particles with a mass on the $1-1000$ GeV scale that interact only via the weak nuclear force. Particles in this class are referred to as Weakly Interacting Massive Particles (WIMPs), and their high masses and low scattering cross sections make them viable dark matter candidates. The rarity of WIMP-nucleus interactions makes them challenging to detect: any background can mask the signal they produce. Background rejection is therefore a major problem in dark matter detection. Many experiments greatly reduce their backgrounds by employing techniques to reject electron recoils. However, nuclear recoil backgrounds, which produce signals similar to what we expect from WIMPs, remain problematic. There are two primary sources of such backgrounds: surface backgrounds and neutron recoils. Surface backgrounds result from radioactivity on the inner surfaces of the detector sending recoiling nuclei into the detector. These backgrounds can be removed with fiducial cuts, at some cost to the experiment's exposure. In this dissertation we briefly discuss a novel technique for rejecting these events based on signals they make in the wavelength shifter coating on the inner surfaces of some detectors. Neutron recoils result from neutrons scattering from nuclei in the detector. These backgrounds may produce a signal identical to what we expect from WIMPs and are extensively discussed here. We additionally present a new tool for calculating ($\\alpha$, n)yields in various materials. We introduce the concept of a neutron veto system designed to shield against, measure, and provide an anti-coincidence veto signal for background neutrons. We discuss the research and

Projectile rapidity dependence in target fragmentation

International Nuclear Information System (INIS)

Haustein, P.E.; Cumming, J.B.; Hseuh, H.C.

1979-01-01

The thick-target, thick-catcher technique was used to determine mean kinetic properties of selected products of the fragmentation of Cu by 1 H, 4 He, and 12 C ions (180 to 28,000 MeV/amu). Momentum transfer, as inferred from F/B ratios, is ovserved to occur most efficiently for the lower velocity projectiles. Recoil properties of target fragments vary strongly with product mass, but show only a weak dependence on projectile type. The projectile's rapidity is shown to be a useful variable for quantitative intercomparison of different reactions. These results indicate that E/sub proj//A/sub proj/ is the dominant parameter which governs the mean recoil behavior of target fragments. 20 references

Coincidence measurements of slow recoil ions with projectile ions in 42-MeV Arq+-Ar collisions

International Nuclear Information System (INIS)

Tonuma, T.; Kumagai, H.; Matsuo, T.; Tawara, H.

1989-01-01

Slow Ar recoil-ion production cross sections by projectiles of 1.05-MeV/amu Ar q+ (q=4,6,8,10,12,14) were measured using a projectile-ion--recoil-ion coincidence technique. The present results indicate that the average recoil ion charges left-angle i right-angle increase with increasing the incident projectile charge q and the number of the lost and captured electrons from and/or into projectiles, whereas the projectile charge-changing cross sections for loss ionization decrease steeply with increasing q for low-charge-state projectiles, and those for transfer ionization increase rapidly with increasing q for high-charge-state projectiles. For Ar projectiles with q=10, which corresponds to the equilibrium charge state of Ar projectiles at the present collision energy, the average recoil-ion charges are nearly the same in both loss and transfer ionization, and a pure ionization process plays a much more important role in producing highly charged recoil ions, in contrast to projectile electron loss or transfer processes, which play a role in other projectile charge states

Atom location using recoil ion spectroscopy

International Nuclear Information System (INIS)

O'Connor, D.J.

1985-01-01

Low energy ion scattering (LEIS) using inert gas and alkali ions is widely used in studies of the surface atomic layer. The extreme surface sensitivity of this technique ensures that it yields both compositional and structural information on clean and adsorbate covered surfaces. Low Energy Negative recoil Spectroscopy (LENRS) has been applied to a study of oxygen on Ni(110) to gauge the sensitivity to coverage and site location

Recoil effects in multiphoton electron-positron pair creation

International Nuclear Information System (INIS)

Krajewska, K.; Kaminski, J. Z.

2010-01-01

Triply differential probability rates for electron-positron pair creation in laser-nucleus collisions, calculated within the S-matrix approach, are investigated as functions of the nuclear recoil. Pronounced enhancements of differential probability rates of multiphoton pair production are found for a nonzero momentum transfer from the colliding nucleus. The corresponding rates show a very dramatic dependence on the polarization of the laser field impinging on the nucleus; only for a linearly polarized light are the multiphoton rates for electron-positron pair production considerably large. We focus therefore on this case. Our numerical results for different geometries of the reaction particles demonstrate that, for the linearly polarized laser field of an infinite extent (which is a good approximation for femtosecond laser pulses), the pair creation is far more efficient if the nucleus is detected in the direction of the laser-field propagation. The corresponding angular distributions of the created particles show that the high-energy pairs are predominantly produced in the plane spanned by the polarization vector and the laser-field propagation direction, while the low-energy pairs are rather spread around the latter of the two directions. The enhancement of differential probability rates at each energy sector, defined by the four-momentum conservation relation, is observed with varying the energy of the produced particles. The total probability rates of pair production are also evaluated and compared with the corresponding results for the case when one disregards the recoil effect. A tremendous enhancement of the total probability rates of the electron-positron pair creation is observed if one takes into account the nuclear recoil.

Production, transport and charge capture measurements of highly charged recoil ions

International Nuclear Information System (INIS)

Trebus, U.E.

1989-01-01

An experiment is described to study highly charged recoil ions on-line to the heavy accelerator UNILAC at GSI. The highly charged recoil ions are produced by heavy-ion bombardment of a gas target. Subsequently the slow highly charged recoil ions are extracted from the ionization volume, and guided through a beam transport line to a Wien filter for charge state selection and to a collision region to study charge transfer processes. Several experiments were carried out to show the efficient charge state separation. Charge states up to q = 15 were observed. When using a retarding field analyzer cross sections for single electron capture were determined for different charge states of Xe q+ for q = 4 to 11 and He gas. The experiments demonstrated increasing charge transfer cross sections with increasing charge state q and indicated the effect of near resonant charge capture for q = 6. The flexible data acquisition system used, is described and other future experiments, such as for instance in flight ion-trapping are indicated in the appendix

Heavy ion elastic recoil detection analysis of optoelectronic and semiconductor devices

Energy Technology Data Exchange (ETDEWEB)

Dytlewski, N.; Cohen, D.D. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia); Johnston, P.; Walker, S. [Royal Melbourne Inst. of Tech., VIC (Australia); Whitlow, H.; Hult, M. [Lund Univ. (Sweden); Oestling, M.; Zaring, C. [Royal Inst. of Tech., Stockholm (Sweden)

1993-12-31

In recent years, the use of heavy ion time-of-flight elastic recoil spectrometry (HIERDA) has been applied to analyse multi-phase, thin layer devices used in optoelectronics, semiconductors and solar power generation. HIERDA gives simultaneously, mass resolved elemental concentration vs depth profiles of the matrix constituents, and is particularly suited to the determination of light elements in a heavy matrix. The beam/target interaction process is similar to RBS, but has the difference that the recoiling target atoms are detected instead of the scattered projectile. High energy, heavy ions beams bombard the sample, ejecting recoil atoms which are detected at a forward angle of 45 deg. A time-of-flight and total energy detection system enables the ejected particle`s mass to be identified, and allows energy spectra to be obtained and interpreted in an analogous way to RBS, but with the important difference that the elemental spectra are separated, and not superimposed on a background as in RBS. Some of the measurements made with a HIERDA system on the ANTARES Tandem Accelerator at ANSTO are described. 1 refs., 4 figs.

Heavy ion elastic recoil detection analysis of optoelectronic and semiconductor devices

Energy Technology Data Exchange (ETDEWEB)

Dytlewski, N; Cohen, D D [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia); Johnston, P; Walker, S [Royal Melbourne Inst. of Tech., VIC (Australia); Whitlow, H; Hult, M [Lund Univ. (Sweden); Oestling, M; Zaring, C [Royal Inst. of Tech., Stockholm (Sweden)

1994-12-31

In recent years, the use of heavy ion time-of-flight elastic recoil spectrometry (HIERDA) has been applied to analyse multi-phase, thin layer devices used in optoelectronics, semiconductors and solar power generation. HIERDA gives simultaneously, mass resolved elemental concentration vs depth profiles of the matrix constituents, and is particularly suited to the determination of light elements in a heavy matrix. The beam/target interaction process is similar to RBS, but has the difference that the recoiling target atoms are detected instead of the scattered projectile. High energy, heavy ions beams bombard the sample, ejecting recoil atoms which are detected at a forward angle of 45 deg. A time-of-flight and total energy detection system enables the ejected particle`s mass to be identified, and allows energy spectra to be obtained and interpreted in an analogous way to RBS, but with the important difference that the elemental spectra are separated, and not superimposed on a background as in RBS. Some of the measurements made with a HIERDA system on the ANTARES Tandem Accelerator at ANSTO are described. 1 refs., 4 figs.

Production, transport and charge capture measurements of highly charged recoil ions

International Nuclear Information System (INIS)

Trebus, U.E.

1989-05-01

An experiment is described to study highly charged recoil ions on-line to the heavy ion accelerator UNILAC at GSI. The highly charged recoil ions are produced by heavy ion bombardment of a gas target. Subsequently the slow highly charged recoil ions are extracted from the ionization volume, and guided through a beam transport line to a Wien filter for charge state selection and to a collision region to study charge transfer processes. Several experiments were carried out to show the efficient charge state separation. Charge states up to q=15 were observed. When using a retarding field analyzer cross sections for single electron capture were determined for different charge states of Xe q+ for q=4 to 11 and He gas. The experiments demonstrated increasing charge transfer cross sections with increasing charge state q and indicated the effect of near resonant charge capture for q=6. The flexible data acquisition system used, is described and other future experiments, such as for instance in flight ion-trapping are indicated in the appendix. (orig.)

Recoil-proton polarization in πp elastic scattering at 547 and 625 MeV/c

International Nuclear Information System (INIS)

Seftor, C.J.; Adrian, S.D.; Briscoe, W.J.; Mokhtari, A.; Taragin, M.F.; Sadler, M.E.; Barlow, D.B.; Nefkens, B.M.K.; Pillai, C.

1989-01-01

The polarization of the recoil proton in π + p and π - p elastic scattering using a liquid-hydrogen target has been measured for backward angles at 547 and 625 MeV/c. The scattered pion and recoil proton were detected in coincidence using the large-acceptance spectrometer to detect and analyze the momentum of the pions and the JANUS polarimeter to identify and measure the polarization of the protons. Results from this experiment agree with other measurements of the recoil polarization, with analyzing-power data previously taken by this group, and with predictions of partial-wave analyses

Recoil Considerations for Shoulder-Fired Weapons

Science.gov (United States)

2012-05-01

than would be deduced from the force levels defined by the pressure-time curve of the cartridge. Further and just like a large-caliber weapon mounted...force. If each of the force curves over the time interval were integrated, the result should be the same as that derived from a ballistic pendulum...Kathe, E.; Dillon, R. Sonic Rarefaction Wave Low Recoil Gun; Report ARCCB-TR-2001; U.S. Army Armament Research, Development, and Engineering Center

Accurate measurements of E2 lifetimes using the coincidence recoil-distance method

International Nuclear Information System (INIS)

Bhalla, R.K.; Poletti, A.R.

1984-01-01

Mean lives of four E2 transitions in the (2s, 1d) shell have been measured using the recoil-distance method (RDM). γ-rays de-exciting the level of interest were detected in coincidence with particles detected in an annular detector at a backward angle thereby reducing the background and producing a beam of recoiling nuclei of well-defined energy and recoil direction. Lifetimes measured were: 22 Ne, 1.275 MeV level (2 + -> 0 + ), 5.16 +- 0.13 ps; 26 Mg, 3.588 MeV level (0 + -> 2 + ), 9.29 +- 0.23 ps; 30 Si, 3.788 MeV level (0 + -> 2 + ), 12.00 +- 0.70 ps; 38 Ar, 3.377 MeV level (0 + -> 2 + ), 34.5 +- 1.5 ps. The present measurements are compared to those of previous investigators. For the 22 Ne level, averaged results from four different measurement techniques are compared and found to be in good agreement. The experimental results are compared to shell-model calculations. (orig.)

Primary processes and ionic reactions in the chemistry of recoiling silicon atoms

International Nuclear Information System (INIS)

Gaspar, P.P.; Garmestani, K.; Boo, B.H.; Stewart, G.W.

1993-01-01

Hot atom chemistry has permitted the elucidation of the chemistry of free atoms, and these include the polyvalent atoms of refractory group 14 elements, that is, carbon, silicon and germanium. Since no more than two bonds are formed normally in a single reactive collision of free atoms, the study on the chemistry of atoms like C, Si and Ge that require the formation of more than two bonds to saturate their chemical valence necessarily involves the study of reactive intermediates. By the studies on the chemistry of recoiling 31 Si atoms, the mechanistic conclusions reached are reported. The most important unanswered questions concerning the reaction of recoiling 31 Si atoms in the systems are shown, and progress has been made toward the answering. By using tetramethyl silane as a trapping agent for silicon ions, it has been established that the reaction of 31 Si ions contributes significantly to the formation of products in recoil systems. The studies by various researchers on this theme are reported. (K.I.)

Test of a superheated superconducting granule detector with nuclear recoil measurements

International Nuclear Information System (INIS)

Berger, C.; Czapek, G.; Diggelmann, U.; Flammer, I.; Frei, D.; Furlan, M.; Gabutti, A.; Janos, S.; Moser, U.; Pretzl, K.; Schmiemann, K.; Perret-Gallix, D.; Konter, J.A.; Mango, S.

1993-01-01

The presented results are part of a Superheated Superconducting Granule (SSG) detector development for neutrinos and dark matter. An aluminum SSG detector was exposed to a 70MeV neutron beam to test the detector sensitivity to nuclear recoils. The neutron scattering angels were determined using a scintillator hodoscope. Coincidences between the SSG and the hodoscope signals have been clearly established. Data were taken at an operating temperature of 120mK for different SSG intrinsic thresholds. The proved sensitivity of the detector to nuclear recoils above 10keV is encouraging for possible applications of SSG as a dark matter detector. (orig.)

Dynamical Formation of Horizons in Recoiling D Branes

CERN Document Server

Ellis, Jonathan Richard; Nanopoulos, Dimitri V; Ellis, John

2000-01-01

A toy calculation of string/D-particle interactions within a world-sheet approach indicates that quantum recoil effects - reflecting the gravitational back-reaction on space-time foam due to the propagation of energetic particles - induces the appearance of a microscopic event horizon, or `bubble', inside which stable matter can exist. The scattering event causes this horizon to expand, but we expect quantum effects to cause it to contract again, in a `bounce' solution. Within such `bubbles', massless matter propagates with an effective velocity that is less than the velocity of light in vacuo, which may lead to observable violations of Lorentz symmetry that may be tested experimentally. The conformal invariance conditions in the interior geometry of the bubbles select preferentially three for the number of the spatial dimensions, corresponding to a consistent formulation of the interaction of D3 branes with recoiling D particles, which are allowed to fluctuate independently only on the D3-brane hypersurface.

Calculations of Total and Differential Solid Angles for a Proton Recoil Solid State Detector

Energy Technology Data Exchange (ETDEWEB)

Konijn, J; Lauber, A; Tollander, B

1963-08-15

The solid angles have been computed for a proton recoil counter consisting of a circular hydrogenous foil viewed by an isotropic neutron point source at different distances from the target foil. Tables are given for the total subtended solid angle as well as the differential energy distribution function of the proton recoil spectrum. The influence of finite foil thickness has also been studied.

A laser ablation ion source for the FRS ion catcher

Energy Technology Data Exchange (ETDEWEB)

Rink, Ann-Kathrin; Ebert, Jens; Petrick, Martin; Reiter, Pascal [Justus Liebig Universitaet Giessen (Germany); Dickel, Timo; Geissel, Hans; Plass, Wolfgang; Scheidenberger, Christoph [Justus Liebig Universitaet Giessen (Germany); GSI, Darmstadt (Germany); Purushothamen, Sivaji [GSI, Darmstadt (Germany)

2013-07-01

The FRS Ion Catcher was developed to serve as test bench for the low energy branch of the Super FRS to slow down exotic nuclei and prepare them for further measurements/ experiments. It consists of a cryogenic stopping cell to thermalise the ions, a diagnostic unit for stopping cell characterisation and various radiofrequency quadrupole structures to guide the ions to the Multiple-Reflection Time-of-Flight Mass Spectrometer for mass measurements, α spectroscopy and isobar separation. To characterise the extraction times of the stopping cell, which is one of the main performance parameters of such a cell, a laser ablation ion source has been develped and tested. This ion source provides a sharply defined starting point of the ions for the extraction time measurement. In the future this source will provide reference ions to calibrate the mass spectrometer for accurate mass measurements.

Superheated superconducting granule detector tested with nuclear recoil measurements

International Nuclear Information System (INIS)

Berger, C.; Czapek, G.; Diggelmann, U.; Flammer, I.; Frei, D.; Furlan, M.; Gabutti, A.; Janos, S.; Moser, U.; Pretzl, K.; Schmiemann, K.; Perret-Gallix, D.; Brandt, B. van den; Konter, J.A.; Mango, S.

1993-01-01

The presented results are part of a superheated superconducting granule (SSG) detector development for neutrino and dark matter. The aim of the experiment was to measure the sensitivity of the detector to nuclear recoil energies when exposed to a 70 MeV neutron beam. The detector consists of a small readout coil (diameter 5 mm, length 10 mm) filled with aluminum granules of average diameter 23 μm embedded in an Al 2 O 3 granulate with a 6% volume filling factor. The neutron scattering angles were determined using a scintillator hodoscope. Coincidences between the SSG and the hodoscope signals have been clearly established. Data were taken at an operating temperature of 120 mK for different SSG intrinsic thresholds. The results prove the sensitivity of the detector to nuclear recoils around 10 keV. (orig.)

Dama annual modulation from electron recoils

OpenAIRE

Foot, R.

2018-01-01

Plasma dark matter, which arises in dissipative dark matter models, can give rise to large annual modulation signals from keV electron recoils. Previous work has argued that the DAMA annual modulation signal might be explained in such a scenario. Detailed predictions are difficult due to the inherent complexities involved in modelling the halo plasma interactions with Earth bound dark matter. Here, we consider a simplified phenomenological model for the dark matter density and temperature nea...

On the limitations introduced by energy spread in elastic recoil detection analysis

International Nuclear Information System (INIS)

Szilagyi, E.

2001-01-01

Improvements in experimental techniques have led to monolayer depth resolution in heavy ion elastic recoil detection analysis (HI-ERDA). Evaluation of the spectra, however, is not trivial. The spectra, using even the best experimental set-up, are subject to finite energy resolution of both extrinsic and intrinsic origin. A proper account for energy spread is necessary to extract the correct depth profile from the measured spectra. With calculation of the correct energy (or depth) resolution of a given method, one can decide in advance whether or not the method will resolve details of interest in the depth profile. To achieve the best depth resolution, it is also possible to find optimum parameters for the experiments. The limitations introduced by the energy spread effects are discussed. An example for simulation is shown for high energy resolution HI-ERDA measurements. Satisfactory agreement between the simulated and the measured HI-ERDA spectra taken by 60 MeV 127 I 23+ ions on highly oriented pyrolythic graphite (HOPG) sample is found, in spite of the non-equilibrium charge state of the recoils and the difference in the stopping powers caused by the given charge state of the incident ion and the recoil, which are not taken into account. To achieve more precise data evaluation these effects should be included in simulation codes, or all the subspectra corresponding to different recoils charge states should be measured and summed

On the limitations introduced by energy spread in elastic recoil detection analysis

Energy Technology Data Exchange (ETDEWEB)

Szilagyi, E. E-mail: szilagyi@rmki.kfki.hu

2001-07-01

Improvements in experimental techniques have led to monolayer depth resolution in heavy ion elastic recoil detection analysis (HI-ERDA). Evaluation of the spectra, however, is not trivial. The spectra, using even the best experimental set-up, are subject to finite energy resolution of both extrinsic and intrinsic origin. A proper account for energy spread is necessary to extract the correct depth profile from the measured spectra. With calculation of the correct energy (or depth) resolution of a given method, one can decide in advance whether or not the method will resolve details of interest in the depth profile. To achieve the best depth resolution, it is also possible to find optimum parameters for the experiments. The limitations introduced by the energy spread effects are discussed. An example for simulation is shown for high energy resolution HI-ERDA measurements. Satisfactory agreement between the simulated and the measured HI-ERDA spectra taken by 60 MeV {sup 127}I{sup 23+} ions on highly oriented pyrolythic graphite (HOPG) sample is found, in spite of the non-equilibrium charge state of the recoils and the difference in the stopping powers caused by the given charge state of the incident ion and the recoil, which are not taken into account. To achieve more precise data evaluation these effects should be included in simulation codes, or all the subspectra corresponding to different recoils charge states should be measured and summed.

Controllability analysis and testing of a novel magnetorheological absorber for field gun recoil mitigation

Science.gov (United States)

Ouyang, Qing; Zheng, Jiajia; Li, Zhaochun; Hu, Ming; Wang, Jiong

2016-11-01

This paper aims to analyze the effects of combined working coils of magnetorheological (MR) absorber on the shock mitigation performance and verify the controllability of MR absorber as applied in the recoil system of a field gun. A physical scale model of the field gun is established and a long-stroke MR recoil absorber with four-stage parallel electromagnetic coils is designed to apply separate current to each stage and generate variable magnetic field distribution in the annular flow channel. Based on dynamic analysis and firing stability conditions of the field gun, ideal recoil force-stroke profiles of MR absorber at different limiting firing angles are obtained. The experimental studies are carried out on an impact test rig under different combinations of current loading: conventional unified control mode, separate control mode and timing control mode. The fullness degree index (FDI) is defined as the quantitative evaluation criterion of the controllability of MR absorber during the whole recoil motion. The results show that the force-stroke profile of the novel MR absorber can approach the ideal curve within 25 degrees of the limiting firing angle through judicious exploitation of the adjustable rheological properties of MR fluid.

Nuclear recoil energy scale in liquid xenon with application to the direct detection of dark matter

International Nuclear Information System (INIS)

Sorensen, Peter; Dahl, Carl Eric

2011-01-01

We show for the first time that the quenching of electronic excitation from nuclear recoils in liquid xenon is well-described by Lindhard theory, if the nuclear recoil energy is reconstructed using the combined (scintillation and ionization) energy scale proposed by Shutt et al. We argue for the adoption of this perspective in favor of the existing preference for reconstructing nuclear recoil energy solely from primary scintillation. We show that signal partitioning into scintillation and ionization is well described by the Thomas-Imel box model. We discuss the implications for liquid xenon detectors aimed at the direct detection of dark matter.

Accurate measurements of E2 lifetimes using the coincidence recoil-distance method

Science.gov (United States)

Bhalla, R. K.; Poletti, A. R.

1984-05-01

Mean lives of four E2 transitions in the (2s, 1d) shell have been measured using the recoil-distance method (RDM), γ-rays de-exciting the level of interest were detected in coincidence with particles detected in an annular detector at a backward angle thereby reducing the background and producing a beam of recoiling nuclei of well-defined energy and recoil direction. Lifetimes measured were: 22Ne, 1.275 MeV level (2 + → 0 +), 5.16±0.13 ps; 26Mg, 3.588 MeV level (0 + → 2 +), 9.29±0.23 ps; 30Si, 3.788 MeV level (0 +→ 2 +), 12.00±0.70 ps; 38Ar, 3.377 MeV level (0 + → 2 +), 34.5±1.5 ps. The present measurements are compared to those of previous investigators. For the 22Ne level, averaged results from four different measurement techniques are compared and found to be in good agreement. The experimental results are compared to shell-model calculations.

Role of the recoil effect in two-center interference in X-ray photoionization

International Nuclear Information System (INIS)

Ueda, K.; Liu, X.-J.; Pruemper, G.; Lischke, T.; Tanaka, T.; Hoshino, M.; Tanaka, H.; Minkov, I.; Kimberg, V.; Gel'mukhanov, F.

2006-01-01

X-ray photoelectron spectra of the N 2 molecule are studied both experimentally and theoretically in the extended energy region up to 1 keV. The ratio of the photoionization cross sections for the gerade and ungerade core levels displays a modulation in the high energy region caused by the two-center interference, as predicted by Cohen and Fano (CF) in 1966. The physical background of this CF effect is the same as in Young's double-slit experiment. We have found that the interference pattern deviates significantly from the CF prediction. The origin of such a breakdown of the CF formula is the scattering of the photoelectron inside the molecule and the momentum transfer from the emitted fast photoelectron to the nuclei. Usually the recoil effect is small. We show that the electron recoil strongly affects the two-center interference pattern. Both stationary and dynamical aspects of the recoil effect shed light on the role of the momentum exchange in the two-center interference

SIMULATIONS OF RECOILING MASSIVE BLACK HOLES IN THE VIA LACTEA HALO

International Nuclear Information System (INIS)

Guedes, J.; Madau, P.; Diemand, J.; Kuhlen, M.; Zemp, M.

2009-01-01

The coalescence of a massive black hole (MBH) binary leads to the gravitational-wave recoil of the system and its ejection from the galaxy core. We have carried out N-body simulations of the motion of a M BH = 3.7 x 10 6 M sun MBH remnant in the 'Via Lactea I' simulation, a Milky Way-sized dark matter halo. The black hole receives a recoil velocity of V kick = 80, 120, 200, 300, and 400 km s -1 at redshift 1.5, and its orbit is followed for over 1 Gyr within a 'live' host halo, subject only to gravity and dynamical friction against the dark matter background. We show that, owing to asphericities in the dark matter potential, the orbit of the MBH is highly nonradial, resulting in a significantly increased decay timescale compared to a spherical halo. The simulations are used to construct a semi-analytic model of the motion of the MBH in a time-varying triaxial Navarro-Frenk-White dark matter halo plus a spherical stellar bulge, where the dynamical friction force is calculated directly from the velocity dispersion tensor. Such a model should offer a realistic picture of the dynamics of kicked MBHs in situations where gas drag, friction by disk stars, and the flattening of the central cusp by the returning black hole are all negligible effects. We find that MBHs ejected with initial recoil velocities V kick ∼> 500 km s -1 do not return to the host center within a Hubble time. In a Milky Way-sized galaxy, a recoiling hole carrying a gaseous disk of initial mass ∼M BH may shine as a quasar for a substantial fraction of its 'wandering' phase. The long decay timescales of kicked MBHs predicted by this study may thus be favorable to the detection of off-nuclear quasar activity.

Experiments with recoil ions and other considerations

Energy Technology Data Exchange (ETDEWEB)

Cocke, C.L.

1987-01-01

Some opportunities in collisions physics with slow, multiply charged ions are addressed. A distinction between inner and outer shell collisions is drawn. The applicability of recoil ion sources to outer shell collision systems is discussed, with emphasis on the quality of the beam desired. An example of an inner shell collision is discussed, and the usefulness of not pushing the collision energy too low is pointed out. 13 refs., 14 figs.

Complete and incomplete fusion dynamics in 20Ne + 165Ho system

International Nuclear Information System (INIS)

Linda, Sneha Bharti; Giri, Pankaj K.; Singh, D.; Kumar, Harish; Afzal Ansari, M.; Ali, Rahbar; Rashid, M.H.; Guin, R.; Das, S.K.

2016-01-01

In the present work, an attempt has been made to address some of the important aspects of CF and ICF dynamics for the system 20 Ne + 165 Ho in the projectile energy range 4-8 MeV/nucleon by employing the recoil catcher technique followed by off-line γ-ray spectroscopy. The excitation functions (EFs) of the two ERs 171 Ta and 168 Hf have been measured. In the present measurement no precursor decay contributions has been measured

Systematics on incomplete fusion dynamics at low energy

International Nuclear Information System (INIS)

Rahbar Ali; Afzal Ansari, M.; Kumar, Harish

2016-01-01

In the present work, an attempt has been made to study CF and ICF reaction dynamics extensively by using activation and particle-γ coincidence techniques. The excitation functions (EFs) of evaporation residues (ERs) in 20 Ne + 55 Mn, 19 F + 144 Sm, 20 Ne + 159 Tb and 16 O + 156 Gd systems in the energy range ∼ 3-8 MeV/nucleon have been measured by using recoil catcher activation technique followed by γ-ray spectrometry

Heavy ion recoil spectrometry of Si{sub x}Ge{sub 1-x} thin films

Energy Technology Data Exchange (ETDEWEB)

Walker, S.R.; Johnston, P.N.; Bubb, I.F. [Royal Melbourne Inst. of Tech., VIC (Australia); Cohen, D.D.; Dytlewski, N. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia); Hult, M.; Whitlow, H.J. [Lund Institute of Technology, Solvegatan (Sweden). Department of Nuclear Physics; Zaring, C.; Oestling, M. [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Solid State Electronics

1993-12-31

Mass and energy dispersive recoil spectrometry employing 77 MeV {sup 127}I ions from ANTARES (FN Tandem) facility at Lucas Heights has been used to examine the isotopic composition of samples of Si{sub x}Ge{sub 1-x} grown at the Australian National University by Electron Beam Evaporation (EBE). The recoiling target nuclei were analysed by a Time Of Flight and Energy (TOF-E) detector telescope composed of two timing pickoff detectors and a surface barrier (energy) detector. From the time of flight and energy, the ion mass can be determined and individual depth distributions for each element can be obtained. Recoil spectrometry has shown the presence of oxygen in the Si{sub x}Ge{sub 1-x} layer and has enabled the separate determination of energy spectra for individual elements. 9 refs., 3 figs.

Heavy ion recoil spectrometry of Si{sub x}Ge{sub 1-x} thin films

Energy Technology Data Exchange (ETDEWEB)

Walker, S R; Johnston, P N; Bubb, I F [Royal Melbourne Inst. of Tech., VIC (Australia); Cohen, D D; Dytlewski, N [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia); Hult, M; Whitlow, H J [Lund Institute of Technology, Solvegatan (Sweden). Department of Nuclear Physics; Zaring, C; Oestling, M [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Solid State Electronics

1994-12-31

Mass and energy dispersive recoil spectrometry employing 77 MeV {sup 127}I ions from ANTARES (FN Tandem) facility at Lucas Heights has been used to examine the isotopic composition of samples of Si{sub x}Ge{sub 1-x} grown at the Australian National University by Electron Beam Evaporation (EBE). The recoiling target nuclei were analysed by a Time Of Flight and Energy (TOF-E) detector telescope composed of two timing pickoff detectors and a surface barrier (energy) detector. From the time of flight and energy, the ion mass can be determined and individual depth distributions for each element can be obtained. Recoil spectrometry has shown the presence of oxygen in the Si{sub x}Ge{sub 1-x} layer and has enabled the separate determination of energy spectra for individual elements. 9 refs., 3 figs.

Recoil ion spectroscopy with heavy ions

International Nuclear Information System (INIS)

Beyer, H.F.; Mann, R.

1984-01-01

This chapter examines the production of very high charge state ions in single ion-atom collisions. Topics considered include some aspects of highly ionized atoms, experimental approaches, the production of highly charged target ions (monoatomic targets, recoil energy distribution, molecular fragmentation, outer-shell rearrangement, lifetime measurements, a comparison of projectile-, target-, and plasma-ion stripping), and secondary collision experiments (selective electron capture, potential applications). The heavy-ion beams for the described experiments were provided by accelerators such as tandem Van de Graaff facility and the UNILAC

Elastic recoil detection (ERD) with extremely heavy ions

International Nuclear Information System (INIS)

Forster, J.S.; Davies, J.A.; Siegele, R.; Wallace, S.G.; Zelenitsky, D.

1996-01-01

Extremely heavy-ion beams such as 209 Bi in elastic recoil detection (ERD) make ERD a uniquely valuable technique for thin-film analysis of elements with mass ≤100. We report ERD measurements of compositional analysis of dinosaur eggshells and bones. We also show the capability of the ERD technique on studies of thin-film, high-temperature superconductors. (orig.)

Low energy recoil detection with a spherical proportional counter

Science.gov (United States)

Savvidis, I.; Katsioulas, I.; Eleftheriadis, C.; Giomataris, I.; Papaevangellou, T.

2018-01-01

We present results for the detection of low energy nuclear recoils in the keV energy region, from measurements performed with the Spherical Proportional Counter (SPC). An 241Am-9Be fast neutron source is used in order to obtain neutron-nucleus elastic scattering events inside the gaseous volume of the detector. The detector performance in the keV energy region was measured by observing the 5.9 keV line of a 55Fe X-ray source, with energy resolution of 10% (σ). The toolkit GEANT4 was used to simulate the irradiation of the detector by an 241Am-9Be source, while SRIM was used to calculate the Ionization Quenching Factor (IQF), the simulation results are compared with the measurements. The potential of the SPC in low energy recoil detection makes the detector a good candidate for a wide range of applications, including Supernova or reactor neutrino detection and Dark Matter (WIMP) searches (via coherent elastic scattering).

Characterization of TiAlN thin film annealed under O2 by in situ time of flight direct recoil spectroscopy/mass spectroscopy of recoiled ions and ex situ x-ray photoelectron spectroscopy

International Nuclear Information System (INIS)

Tempez, A.; Bensaoula, A.; Schultz, A.

2002-01-01

The oxidation of an amorphous TiAlN coating has been studied by in situ direct recoil spectroscopy (DRS) and mass spectroscopy of recoiled ions (MSRI) and ex situ x-ray photoelectron spectroscopy (XPS). DRS and MSRI monitored the changes in surface composition as the sample was heated to 460 deg. C under an 18 O 2 pressure of 10 -6 Torr. Angular resolved XPS data were acquired for thickness-dependence information. The initial surface was partially oxidized from air exposure. Both DRS and XPS showed the Al-rich near surface and the presence of N in the subsurface. As shown by DRS and MSRI, oxidation at elevated temperatures yielded surface nitrogen loss and Ti enrichment. XPS confirmed the preferential formation of TiO 2 on the surface. This study also provides a comparison between the direct recoil (neutrals and ions) and the ionic recoil signals. In our conditions, the negative ionic fraction of all elements except H tracks their true surface content variations given by DRS. The results were compared with early work performed on identical samples. In this case the TiAlN film was oxidized with an O 2 pressure in the mTorr range and the surface changes are followed in situ by positive MSRI and XPS. This experiment also indicates that Al and N are buried under TiO 2 but from 600 deg. C

Photoproduction of pions on nuclear in chiral bag model with account of motion effects of recoil nucleon

International Nuclear Information System (INIS)

Dorokhov, A.E.; Kanokov, Z.; Musakhanov, M.M.; Rakhimov, A.M.

1989-01-01

Pion production on a nucleon is studied in the chiral bag model (CBM). A CBM version is investigated in which the pions get into the bag and interact with quarks in a pseudovector way in the entire volume. Charged pion photoproduction amplitudes are found taking into account the recoil nucleon motion effects. Angular and energy distributions of charged pions, polarization of the recoil nucleon, multipoles are calculated. The recoil effects are shon to give an additional contribution to the static approximation of order of 10-20%. At bag radius value R=1 in the calculations are consistent with the experimental data

Hydrogen depth profiling using elastic recoil detection

International Nuclear Information System (INIS)

Doyle, B.L.; Peercy, P.S.

1979-01-01

The elastic recoil detection (ERD) analysis technique for H profiling in the near surface regions of solids is described. ERD is shown to have the capability of detecting H and its isotopes down to concentrations of approx. 0.01 at. % with a depth resolution of a few hundred angstroms. Is is demonstrated that 2.4-MeV He ions can be used successfully to profile 1 H and 2 D using this technique. 12 figures

Proceedings of the symposium on measurements of neutron energy spectra using recoil proton proportional counters

International Nuclear Information System (INIS)

Urabe, Itsumasa

1986-01-01

This is a report of the symposium on measurements of neutron energy spectra using recoil proton proportional counters held at the Research Reactor Institute of Kyoto University on January 27 in 1986. An energy resolution, wall effects of response functions, n · γ discrimination methods and other fundamental properties of recoil proton counters are discussed for a new development of an application of this counter. (author)

Radiation Simulations and Development of Concepts for High Power Beam Dumps, Catchers and Pre-separator Area Layouts for the Fragment Separators for RIA

CERN Document Server

Ronningen, Reginald; Beene, James R; Blideanu, Valetin; Boles, Jason; Bollen, Georg; Burgess, Thomas; Carter, Ken; Conner, David L; Gabriel, Tony A; Geissel, Hans; Gomes, Itacil C; Heilbronn, Lawrence; Iwase, Hiroshi; Lawton, Don; Levand, Anthony; Mansur, Louis; Momozaki, Yoichi; Morrissey, David; Nolen, Jerry; Reed, Claude; Remec, Igor; Rennich, Mark; Reyes, Susana; Sherrill, Bradley; Stein, Werner; Stoyer, Mark; Stracener, Dan; Wendel, Mark; Zeller, Al

2005-01-01

The development of high-power beam dumps and catchers, and pre-separator layouts for proposed fragment separators of the Rare-Isotope Accelerator (RIA) facility are important in realizing how to handle the 400 kW in the primary beam. We will present examples of pre-conceptual designs of beam dumps, fragment catchers, and the pre-separator layout. We will also present examples of ongoing work on radiation simulations using the heavy-ion-transport code PHITS, characterizing the secondary radiation produced by the high-power ion beams interacting with these devices. Results on radiation heating of targets, magnet coils, associated hardware and shielding, component activation, and levels of radiation dose will be presented. These initial studies will yield insight into the impact of the high-power dissipation on fragment separator design, remote handling concepts, nuclear safety and potential facility hazard classification, shielding design, civil construction design, component design, and material choices. Furth...

Deuterium electrodisintegration at high recoil momentum

International Nuclear Information System (INIS)

Steenholen, G.

1996-01-01

The availability of continuous electron beams made it possible to carry out various deuterium electro-disintegration experiments in kinematical domains corresponding to a high recoil momentum. Three such experiments are discussed: 1) the left-right asymmetry with respect to the direction of the momentum transfer has been measured with good precision; 2) cross sections have been obtained in a kinematical region well above the quasi-elastic peak; 3) data have been taken in quasi-elastic kinematics that can be used to study high-momentum components in the deuterium wave function [ru

Magneto optical trap recoil ion momentum spectroscopy: application to ion-atom collisions

International Nuclear Information System (INIS)

Blieck, J.

2008-10-01

87 Rb atoms have been cooled, trapped and prepared as targets for collision studies with 2 and 5 keV Na + projectiles. The physics studied deals with charge exchange processes. The active electron, which is generally the most peripheral electron of the atomic target, is transferred from the target onto the ionic projectile. The ionized target is called recoil ion. The technique used to study this physics is the MOTRIMS (Magneto Optical Trap Recoil Ion Momentum Spectroscopy) technique, which combines a magneto optical trap and a recoil ion momentum spectrometer. The spectrometer is used for the measurement of the recoil ions momentum, which gives access to all the information of the collision: the Q-value (which is the potential energy difference of the active electron on each particle) and the scattering angle of the projectile. The trap provides extremely cold targets to optimize the measurement of the momentum, and to release the latter from thermal motion. Through cinematically complete experiments, the MOTRIMS technique gives access to better resolutions on momentum measurements. Measurements of differential cross sections in initial and final capture states and in scattering angle have been done. Results obtained for differential cross sections in initial and final states show globally a good agreement with theory and an other experiment. Nevertheless, discrepancies with theory and this other experiment are shown for the measurements of doubly differential cross sections. These discrepancies are not understood yet. The particularity of the experimental setup designed and tested in this work, namely a low background noise, allows a great sensitivity to weak capture channels, and brings a technical and scientific gain compared with previous works. (author)

Constraints on the Nature of CID-42: Recoil Kick or Supermassive Black Hole Pair?

Science.gov (United States)

Blecha, Laura; Civano, Francesca; Elvis, Martin; Loeb, Abraham

2012-01-01

The galaxy CXOC J100043.1+020637, also known as CID-42, is a highly unusual object. An apparent galaxy merger remnant, it displays signatures of both an inspiraling, kiloparsecscale active galactic nucleus (AGN) pair and of a recoiling AGN with a kick velocity approximately greater than 1300 km s(exp -1). Among recoiling AGN candidates, CID-42 alone has both spatial offsets (in optical and X-ray bands) and spectroscopic offsets. In order to constrain the relative likelihood of both scenarios, we develop models using hydrodynamic galaxy merger simulations coupled with radiative transfer calculations. Our gas-rich, major merger models are generally well matched to the galactic morphology and to the inferred stellar mass and star formation rate. We show that a recoiling supermassive black hole (SMBH) in CID-42 should be observable as an AGN at the time of observation. However, in order for the recoiling AGN to produce narrow-line emission, it must be observed shortly after the kick while it still inhabits a dense gaseous region, implying a large total kick velocity (vk approximately greater than 2000 km s(exp -1)). For the dual AGN scenario, an unusually large broad-line offset is required, and the best match to the observed morphology requires a galaxy that is less luminous than CID-42. Further, the lack of X-ray emission from one of the two optical nuclei is not easily attributed to an intrinsically quiescent SMBH or to a Compton-thick galactic environment. While the current data do not allow either the recoiling or the dual AGN scenario for CID-42 to be excluded, our models highlight the most relevant parameters for distinguishing these possibilities with future observations. In particular, high-quality, spatially-resolved spectra that can pinpoint the origin of the broad and narrow line features will be critical for determining the nature of this unique source.

Optimizing recoil-isomer tagging with the Argonne fragment mass analyzer

International Nuclear Information System (INIS)

Garnsworthy, A.B.; Lister, C.J.; Regan, P.H.; Blank, B.B.; Cullen, I.J.; Gros, S.; Henderson, D.J.; Jones, G.A.; Liu, Z.; Seweryniak, D.; Shumard, B.R.; Thompson, N.J.; Williams, S.J.; Zhu, S.

2008-01-01

A new focal plane detector arrangement for the Fragment Mass Analyzer (FMA) has been built and tested at Argonne National Laboratory. This set-up is particularly sensitive for performing Recoil-Isomer Tagging on nuclei with isomeric states with lifetimes in the microsecond range. Recoiling nuclei from fusion-evaporation reactions at the target position are dispersed by their ratio of mass to charge (A/q) by the FMA and stopped in low pressure gas (air) at the focal plane. Subsequent gamma decays from isomeric states in the reaction products are observed using Ge detectors. A constant gas flow through the focal plane chamber efficiently removes longer-lived beta-decaying species from sight of the detectors. This set-up has been commissioned successfully with the microsecond isomer in 80 Rb, populated via the 52 Cr( 32 S, 3pn) reaction at 135 MeV

50 CFR Table 47a to Part 679 - Percent of the AFA Catcher/Processor Sector's Pollock Allocation, Numbers of Chinook Salmon Used...

Science.gov (United States)

2010-10-01

... Sector's Pollock Allocation, Numbers of Chinook Salmon Used To Calculate the Opt-out Allocation and... Catcher/Processor Sector's Pollock Allocation, Numbers of Chinook Salmon Used To Calculate the Opt-out... pollock Column E Number of Chinook salmon for the opt-out allocation (8,093) Column F Number of Chinook...

Detection of nuclear recoils in prototype dark matter detectors, made from Al, Sn and Zn superheated superconducting granules

International Nuclear Information System (INIS)

Abplanalp, M.; Van den Brandt, B.; Konter, J.A.; Mango, S.

1995-01-01

This work is part of an ongoing project to develop a superheated superconducting granule (SSG) detector for cold dark matter and neutrinos. The response of SSG devices to nuclear recoils has been explored irradiating SSG detectors with a 70 MeV neutron beam. The aim of the experiment was to test the sensitivity of Sn, Al and Zn SSG detectors to nuclear recoil energies down to a few keV. The detector consisted of a hollow teflon cylinder (0.1 cm 3 inner volume) filled with tiny superconducting metastable granules embedded in a dielectric medium. The nuclear recoil energies deposited in the SSG were determined measuring the neutron scattering angles with a neutron hodoscope. Coincidences in time between the SSG and the hodoscope signals have been clearly established. In this paper the results of the neutron irradiation experiments at different SSG intrinsic thresholds are discussed and compared to Monte Carlo simulations. The results show that SSG are sensitive to recoil energies down to similar 1 keV. The limited angular resolution of the neutron hodoscope prevented us from measuring the SSG sensitivity to even lower recoil energies. (orig.)

Recoil range distribution measurement in 20Ne + 181Ta reaction

International Nuclear Information System (INIS)

Tripathi, R.; Sudarshan, K.; Goswami, A.; Guin, R.; Reddy, A.V.R.

2005-01-01

In order to investigate linear momentum transfer in various transfer channels in 20 Ne + 181 Ta, recoil range distribution measurements have been carried out at E lab = 180 MeV, populating significant number of l-waves above l crit

Implantation of 111In in NTDSi by heavy ion recoil technique

International Nuclear Information System (INIS)

Thakare, S.V.; Tomar, B.S.

1998-01-01

Heavy ion recoil implantation technique has been used to implant 111 In in n-type silicon using medium energy heavy ion accelerator Pelletron, at TIFR, Colaba, Mumbai. The nuclear reaction used for this purpose was 109 Ag( 7 Li,p4n) 111 In. The beam energy was optimised to be 50 MeV for maximum concentration of the implanted probe atoms. The gamma-ray spectrum of the implanted sample after 24 hours was found to contain only 171 and 245 keV gamma rays of 111 In. The penetration depth of ion is increased to 1.6 μm by heavy ion recoil implantation technique as compared to 0.16 μm with the conventional ion implantation technique. (author)

Binary black holes: Spin dynamics and gravitational recoil

International Nuclear Information System (INIS)

Herrmann, Frank; Hinder, Ian; Shoemaker, Deirdre M.; Laguna, Pablo; Matzner, Richard A.

2007-01-01

We present a study of spinning black hole binaries focusing on the spin dynamics of the individual black holes as well as on the gravitational recoil acquired by the black hole produced by the merger. We consider two series of initial spin orientations away from the binary orbital plane. In one of the series, the spins are antialigned; for the second series, one of the spins points away from the binary along the line separating the black holes. We find a remarkable agreement between the spin dynamics predicted at 2nd post-Newtonian order and those from numerical relativity. For each configuration, we compute the kick of the final black hole. We use the kick estimates from the series with antialigned spins to fit the parameters in the Kidder kick formula, and verify that the recoil in the direction of the orbital angular momentum is ∝sinθ and on the orbital plane ∝cosθ, with θ the angle between the spin directions and the orbital angular momentum. We also find that the black hole spins can be well estimated by evaluating the isolated horizon spin on spheres of constant coordinate radius

Citizen Science and Event-Based Science Education with the Quake-Catcher Network

Science.gov (United States)

DeGroot, R. M.; Sumy, D. F.; Benthien, M. L.

2017-12-01

The Quake-Catcher Network (QCN, quakecatcher.net) is a collaborative, citizen-science initiative to develop the world's largest, low-cost strong-motion seismic network through the utilization of sensors in laptops and smartphones or small microelectromechanical systems (MEMS) accelerometers attached to internet-connected computers. The volunteer computers monitor seismic motion and other vibrations and send the "triggers" in real-time to the QCN server hosted at the University of Southern California. The QCN servers sift through these signals and determine which ones represent earthquakes and which ones represent cultural noise. Data collected by the Quake-Catcher Network can contribute to better understanding earthquakes, provide teachable moments for students, and engage the public with authentic science experiences. QCN partners coordinate sensor installations, develop QCN's scientific tools and engagement activities, and create next generation online resources. In recent years, the QCN team has installed sensors in over 225 K-12 schools and free-choice learning institutions (e.g. museums) across the United States and Canada. One of the current goals of the program in the United States is to establish several QCN stations in K-12 schools around a local museum hub as a means to provide coordinated and sustained educational opportunities leading up to the yearly Great ShakeOut Earthquake Drill, to encourage citizen science, and enrich STEM curriculum. Several school districts and museums throughout Southern California have been instrumental in the development of QCN. For educators QCN fulfills a key component of the Next Generation Science Standards where students are provided an opportunity to utilize technology and interface with authentic scientific data and learn about emerging programs such as the ShakeAlert earthquake early warning system. For example, Sunnylands Center in Rancho Mirage, CA leads Coachella Valley Hub, which serves 31 K-12 schools, many of

DVCS at HERMES. The recoil detector and transverse target spin asymmetries

Energy Technology Data Exchange (ETDEWEB)

Murray, M.J.

2008-02-15

The HERMES experiment is a large forward angle spectrometer located at the HERA accelerator ring at DESY, Hamburg. One of the most exciting topics studied at HERMES is Deeply Virtual Compton Scattering (DVCS) which is the simplest interaction that provides a gateway for access to Generalised Parton Distributions (GPDs). GPDs are a theoretical framework which can be used to calculate the total angular momentum of the quarks in the nucleon. As such, they provide one piece of the puzzle of nucleonic spin structure. In 2005, HERMES was upgraded in the target region with a Recoil Detector that allows it to make truly exclusive measurements of the DVCS interaction for the first time. The design and construction of the Recoil Detector is discussed herein, in addition to a complete analysis of the Transverse Target Spin Asymmetry (TTSA) in DVCS. Experimental facilities that enable measurement of this asymmetry are rare. The importance of the information on the TTSA from HERMES is made yet greater as the transversely polarised target that allows the asymmetry to be measured has been replaced by an unpolarised target. This was to allow the Recoil Detector to be installed. The final stage of this thesis shows a model-dependent method for constraining the angular momentum of the quarks in the nucleon and speculates as to the other pieces of the spin puzzle. (orig.)

DVCS at HERMES. The recoil detector and transverse target spin asymmetries

International Nuclear Information System (INIS)

Murray, M.J.

2008-02-01

The HERMES experiment is a large forward angle spectrometer located at the HERA accelerator ring at DESY, Hamburg. One of the most exciting topics studied at HERMES is Deeply Virtual Compton Scattering (DVCS) which is the simplest interaction that provides a gateway for access to Generalised Parton Distributions (GPDs). GPDs are a theoretical framework which can be used to calculate the total angular momentum of the quarks in the nucleon. As such, they provide one piece of the puzzle of nucleonic spin structure. In 2005, HERMES was upgraded in the target region with a Recoil Detector that allows it to make truly exclusive measurements of the DVCS interaction for the first time. The design and construction of the Recoil Detector is discussed herein, in addition to a complete analysis of the Transverse Target Spin Asymmetry (TTSA) in DVCS. Experimental facilities that enable measurement of this asymmetry are rare. The importance of the information on the TTSA from HERMES is made yet greater as the transversely polarised target that allows the asymmetry to be measured has been replaced by an unpolarised target. This was to allow the Recoil Detector to be installed. The final stage of this thesis shows a model-dependent method for constraining the angular momentum of the quarks in the nucleon and speculates as to the other pieces of the spin puzzle. (orig.)

Implantation, recoil implantation, and sputtering

International Nuclear Information System (INIS)

Kelly, R.

1984-01-01

Underlying ion-beam modification of surfaces is the more basic subject of particle-surface interaction. The ideas can be grouped into forward and backward features, i.e. those affecting the interior of the target and those leading to particle expulsion. Forward effects include the stopping of the incident particles and the deposition of energy, both governed by integral equations which are easily set up but difficult to solve. Closely related is recoil implantation where emphasis is placed not on the stopping of the incident particles but on their interaction with target atoms with resulting implantation of these atoms. Backward effects, all of which are denoted as sputtering, are in general either of collisional, thermal, electronic, or exfoliational origin. (Auth.)

Use of nuclear recoil for separating 228Ra, 224Ra, and 233Pa from colloidal thorium

International Nuclear Information System (INIS)

Beydon, J.; Gratot, I.

1968-01-01

By using α-recoil it is possible to separate by dialysis the α disintegration products (224 Ra; 228 Ra) of thorium from colloidal thorium hydroxide.The use of n, γ recoil allows the separation of 233 Pa produced by the neutron irradiation of thorium, on condition that the colloidal thorium hydroxide is irradiated in the presence of a dispersing. (author) [fr

Electrochemical etching amplification of low-let recoil particle tracks in polymers for fast neutron dosimetry

International Nuclear Information System (INIS)

Sohrabi, M.; Morgan, K.Z.

1975-11-01

An electrochemical etching method for the amplification of fast-neutron-induced recoil particle tracks in polymers was investigated. The technique gave superior results over those obtained by conventional etching methods especially when polycarbonate foils were used for recoil particle track amplification. Electrochemical etching systems capable of multi-foil processing were designed and constructed to demonstrate the feasibility of the techniques for large-scale neutron dosimetry. Electrochemical etching parameters were studied including the nature or type of the polymer foil used, foil thickness and its effect on etching time, the applied voltage and its frequency, the chemical composition, concentration, and temperature of the etchant, distance and angle between the electrodes, and the type of particles such as recoil particles including protons. Recoil particle track density, mean track diameter, and optical density as functions of the mentioned parameters were determined. Each parameter was found to have a distinct effect on the etching results in terms of the measured responses. Several new characteristics of this fast neutron dosimetry method were studied especially for personnel dosimetry using various radiation sources such as nuclear reactors, medical cyclotrons, and isotopic neutron sources. The dose range, neutron energy dependence, directional response, fading characteristics, neutron threshold energy, etc. were investigated

Recoil velocity at second post-Newtonian order for spinning black hole binaries

International Nuclear Information System (INIS)

Racine, Etienne; Buonanno, Alessandra; Kidder, Larry

2009-01-01

We compute the flux of linear momentum carried by gravitational waves emitted from spinning binary black holes at second post-Newtonian (2PN) order for generic orbits. In particular we provide explicit expressions of three new types of terms, namely, next-to-leading order spin-orbit terms at 1.5 post-Newtonian (1.5PN) order, spin-orbit tail terms at 2PN order, and spin-spin terms at 2PN order. Restricting ourselves to quasicircular orbits, we integrate the linear-momentum flux over time to obtain the recoil velocity as function of orbital frequency. We find that in the so-called superkick configuration the higher-order spin corrections can increase the recoil velocity up to a factor ∼3 with respect to the leading-order PN prediction. Whereas the recoil velocity computed in PN theory within the adiabatic approximation can accurately describe the early inspiral phase, we find that its fast increase during the late inspiral and plunge, and the arbitrariness in determining until when it should be trusted, makes the PN predictions for the total recoil not very accurate and robust. Nevertheless, the linear-momentum flux at higher PN orders can be employed to build more reliable resummed expressions aimed at capturing the nonperturbative effects until merger. Furthermore, we provide expressions valid for generic orbits, and accurate at 2PN order, for the energy and angular momentum carried by gravitational waves emitted from spinning binary black holes. Specializing to quasicircular orbits we compute the spin-spin terms at 2PN order in the expression for the evolution of the orbital frequency and found agreement with Mikoczi, Vasuth, and Gergely. We also verified that in the limit of extreme mass ratio our expressions for the energy and angular momentum fluxes match the ones of Tagoshi, Shibata, Tanaka, and Sasaki obtained in the context of black hole perturbation theory.

Treatment for the recoil effects of the multi-step heavy-ion nucleon transfers with the orthogonalized coupled-reaction-channel theory

International Nuclear Information System (INIS)

Misono, S.; Imanishi, B.

1997-02-01

We have investigated recoil effects in heavy-ion reactions for the nucleon transfers, and the validity of the spatially local approximation for the non-local transfer interaction defined by the orthogonalized coupled-reaction-channel (OCRC) theory. This approximation makes it easier to treat multi-step transfer processes with the coupled channel method and makes it possible to define the nucleon molecular orbitals with the inclusion of the recoil effects. The transfer interaction is expanded in a power series of the momentum operator, and is approximated by the first order term, i.e., the spatially local term. The numerical calculation for the core-symmetric systems 12 C+ 13 C and 16 O+ 17 O with this approximation shows that the recoil effects are well included in the results at energies lower than a few MeV/nucleon. Furthermore, the OCRC formalism allows us even to employ the complete no-recoil approximation for the calculation of cross sections, even though it is not adequate to use this approximation in the distorted wave Born approximation (DWBA) method. As to polarization, however, the no-recoil approximation is not good even in the OCRC formalism. We discuss the recoil effects on nucleon molecular-orbital states. It is shown that states of the covalent molecular orbitals of the valence (transferred) nucleon are little affected by the recoil effects, as already suggested by Korotky et al. in the full finite-range DWBA analysis of the transfer reaction, 13 C( 13 C, 12 C) 14 C. (author). 59 refs

Detailed Characterization of Nuclear Recoil Pulse Shape Discrimination in the Darkside-50 Direct Dark Matter Experiment

Science.gov (United States)

Ludert, Erin Edkins

While evidence of non-baryonic dark matter has been accumulating for decades, its exact nature continues to remain a mystery. Weakly Interacting Massive Particles (WIMPs) are a well motivated candidate which appear in certain extensions of the Standard Model, independently of dark matter theory. If such particles exist, they should occasionally interact with particles of normal matter, producing a signal which may be detected. The DarkSide-50 direct dark matter experiment aims to detect the energy of recoiling argon atoms due to the elastic scattering of postulated WIMPs. In order to make such a discovery, a clear understanding of both the background and signal region is essential. This understanding requires a careful study of the detector's response to radioactive sources, which in turn requires such sources may be safely introduced into or near the detector volume and reliably removed. The CALibration Insertaion System (CALIS) was designed and built for this purpose in a joint effort between Fermi National Laboratory and the University of Hawaii. This work describes the design and testing of CALIS, its installation and commissioning at the Laboratori Nazionali del Gran Sasso (LNGS) and the multiple calibration campaigns which have successfully employed it. As nuclear recoils produced by WIMPs are indistinguishable from those produced by neutrons, radiogenic neutrons are both the most dangerous class of background and a vital calibration source for the study of the potential WIMP signal. Prior to the calibration of DarkSide-50 with radioactive neutron sources, the acceptance region was determined by the extrapolation of nuclear recoil data from a separate, dedicated experiment, ScENE, which measured the distribution of the pulse shape discrimination parameter, f 90, for nuclear recoils of known energies. This work demonstrates the validity of the extrapolation of ScENE values to DarkSide-50, by direct comparison of the f90 distribution of nuclear recoils from Sc

A Measurement of the Recoil Polarization of Electroproduced Λ(1116)

Energy Technology Data Exchange (ETDEWEB)

McAleer, Simeon B. [Florida State Univ., Tallahassee, FL (United States)

2002-01-01

The CEBAF Large Acceptance Spectrometer at the Thomas Jefferson National Laboratory was used to study the reaction e + p → e' + K⁺ + Λ(1116) for events where Λ(1116) subsequently decayed via the channel Λ(1116) → p + π^-. Data were taken at incident electron beam energies of 2.5, 4.0, and 4.2 GeV during the 1999 E1C run period. They hyperon production spectra span the Q² range from 0.5 to 2.8 GeV² and nearly the entire range in the center of mass angles. The proton angular distribution in the Λ(1116) rest frame is used to deduce the recoil polarization of the hyperon, and the W and cos θ$K+\\atop{cm}$ dependence of the recoil polarization will be presented. The data show sizeable negative polarizations for the Λ(1116) as a function of both cos θ$K+\\atop{cm}$ and W.

The HERMES recoil photon detector and the study of deeply virtual Compton scattering

Energy Technology Data Exchange (ETDEWEB)

Hulse, Charlotte van

2011-03-15

The study of deeply virtual Compton scattering (DVCS) gives information about the contribution of the quark orbital angular momentum to the spin of the proton. DVCS has been studied at the HERMES experiment at DESY in Hamburg. Here 27.6 GeV longitudinally polarized electrons and positrons were scattered off a gaseous proton target. For the analysis of DVCS the recoiling proton could not be detected, but was reconstructed via its missing mass. This method suffers, however, from a 14% background contribution, mainly originating from associated DVCS. In this process the proton does not stay in its ground state but is excited to a {delta}{sup +} resonance. In order to reduce the background contribution down to less than 1%, a recoil detector was installed in the HERMES experiment beginning of 2006. This detector consists of three subcomponents, of which one is the photon detector. The main function of the photon detector is the detection of {delta}{sup +} decay photons. The photon detector was started up and commissioned for the analysis of (associated) DVCS. Subsequently DVCS and associated DVCS were analyzed using the recoil detector. (orig.)

No-recoil approximation to the knock-on exchange potential in the double folding model for heavy-ion collisions

International Nuclear Information System (INIS)

Hagino, K.; Takehi, T.; Takigawa, N.

2006-01-01

We propose the no-recoil approximation, which is valid for heavy systems, for a double folding nucleus-nucleus potential. With this approximation, the nonlocal knock-on exchange contribution becomes a local form. We discuss the applicability of this approximation for elastic scattering of the 6 Li + 40 Ca system. We find that, for this and heavier systems , the no-recoil approximation works as good as another widely used local approximation that employs a local plane wave for the relative motion between the colliding nuclei. We also compare the results of the no-recoil calculations with those of the zero-range approximation often used to handle the knock-on exchange effect

A new recoil distance technique using low energy coulomb excitation in inverse kinematics

Energy Technology Data Exchange (ETDEWEB)

Rother, W., E-mail: wolfram.rother@googlemail.com [Institut fuer Kernphysik der Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); Dewald, A.; Pascovici, G.; Fransen, C.; Friessner, G.; Hackstein, M. [Institut fuer Kernphysik der Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); Ilie, G. [Wright Nuclear Structure Laboratory, Yale University, New Haven, CT 06520 (United States); National Institute of Physics and Nuclear Engineering, P.O. Box MG-6, Bucharest-Magurele (Romania); Iwasaki, H. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 (United States); Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Jolie, J. [Institut fuer Kernphysik der Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); Melon, B. [Dipartimento di Fisica, Universita di Firenze and INFN Sezione di Firenze, Sesto Fiorentino (Firenze) I-50019 (Italy); Petkov, P. [Institut fuer Kernphysik der Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); INRNE-BAS, Sofia (Bulgaria); Pfeiffer, M. [Institut fuer Kernphysik der Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); Pissulla, Th. [Institut fuer Kernphysik der Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); Bundesumweltministerium, Robert-Schuman-Platz 3, D - 53175 Bonn (Germany); Zell, K.-O. [Institut fuer Kernphysik der Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); Jakobsson, U.; Julin, R.; Jones, P.; Ketelhut, S.; Nieminen, P.; Peura, P. [Department of Physics, University of Jyvaeskylae, P.O. Box 35, FI-40014 (Finland); and others

2011-10-21

We report on the first experiment combining the Recoil Distance Doppler Shift technique and multistep Coulomb excitation in inverse kinematics at beam energies of 3-10 A MeV. The setup involves a standard plunger device equipped with a degrader foil instead of the normally used stopper foil. An array of particle detectors is positioned at forward angles to detect target-like recoil nuclei which are used as a trigger to discriminate against excitations in the degrader foil. The method has been successfully applied to measure lifetimes in {sup 128}Xe and is suited to be a useful tool for experiments with radioactive ion beams.

Detailed Characterization of Nuclear Recoil Pulse Shape Discrimination in the DarkSide-50 Direct Dark Matter Experiment

Energy Technology Data Exchange (ETDEWEB)

Edkins, Erin Elisabeth [Univ. of Hawaii, Honolulu, HI (United States)

2017-05-01

While evidence of non-baryonic dark matter has been accumulating for decades, its exact nature continues to remain a mystery. Weakly Interacting Massive Particles (WIMPs) are a well motivated candidate which appear in certain extensions of the Standard Model, independently of dark matter theory. If such particles exist, they should occasionally interact with particles of normal matter, producing a signal which may be detected. The DarkSide-50 direct dark matter experiment aims to detect the energy of recoiling argon atoms due to the elastic scattering of postulated WIMPs. In order to make such a discovery, a clear understanding of both the background and signal region is essential. This understanding requires a careful study of the detector's response to radioactive sources, which in turn requires such sources may be safely introduced into or near the detector volume and reliably removed. The CALibration Insertaion System (CALIS) was designed and built for this purpose in a j oint effort between Fermi National Laboratory and the University of Hawaii. This work describes the design and testing of CALIS, its installation and commissioning at the Laboratori Nazionali del Gran Sasso (LNGS) and the multiple calibration campaigns which have successfully employed it. As nuclear recoils produced by WIMPs are indistinguishable from those produced by neutrons, radiogenic neutrons are both the most dangerous class of background and a vital calibration source for the study of the potential WIMP signal. Prior to the calibration of DarkSide-50 with radioactive neutron sources, the acceptance region was determined by the extrapolation of nuclear recoil data from a separate, dedicated experiment, ScENE, which measured the distribution of the pulse shape discrimination parameter, $f_{90}$, for nuclear recoils of known energies. This work demonstrates the validity of the extrapolation of ScENE values to DarkSide-50, by direct comparison of the $f_{90}$ distributio n of nuclear

Calculations of charged-particle recoils, slowing-down spectra, LET and event-size distributions for fast neutrons and comparisons with measurements

International Nuclear Information System (INIS)

Borak, T.B.; Stinchcomb, T.G.

1979-01-01

A rapid system has been developed for computing charged-particle distributions generated in tissue by any neutron spectra less than 4 MeV. Oxygen and carbon recoils were derived from R-matrix theory, and hydrogen recoils were obtained from cross-section evaluation. Application to two quite different fission-neutron spectra demonstrates the flexibility of this method for providing spectral details of the different types of charged-particle recoils. Comparisons have been made between calculations and measurements of event-size distributions for a sphere of tissue 1 μm in diameter irradiated by these two neutron spectra. LET distributions have been calculated from computed charged-particle recoils and also derived from measurements using the conventional approximation that all charged particles traverse the chamber. The limitations of the approximation for these neutron spectra are discussed. (author)

First high-statistics and high-resolution recoil-ion data from the WITCH retardation spectrometer

Science.gov (United States)

Finlay, P.; Breitenfeldt, M.; Porobić, T.; Wursten, E.; Ban, G.; Beck, M.; Couratin, C.; Fabian, X.; Fléchard, X.; Friedag, P.; Glück, F.; Herlert, A.; Knecht, A.; Kozlov, V. Y.; Liénard, E.; Soti, G.; Tandecki, M.; Traykov, E.; Van Gorp, S.; Weinheimer, Ch.; Zákoucký, D.; Severijns, N.

2016-07-01

The first high-statistics and high-resolution data set for the integrated recoil-ion energy spectrum following the β^+ decay of 35Ar has been collected with the WITCH retardation spectrometer located at CERN-ISOLDE. Over 25 million recoil-ion events were recorded on a large-area multichannel plate (MCP) detector with a time-stamp precision of 2ns and position resolution of 0.1mm due to the newly upgraded data acquisition based on the LPC Caen FASTER protocol. The number of recoil ions was measured for more than 15 different settings of the retardation potential, complemented by dedicated background and half-life measurements. Previously unidentified systematic effects, including an energy-dependent efficiency of the main MCP and a radiation-induced time-dependent background, have been identified and incorporated into the analysis. However, further understanding and treatment of the radiation-induced background requires additional dedicated measurements and remains the current limiting factor in extracting a beta-neutrino angular correlation coefficient for 35Ar decay using the WITCH spectrometer.

Velocity dependence of transient hyperfine field at Pt ions rapidly recoiling through magnetized Fe

International Nuclear Information System (INIS)

Stuchbery, A.E.; Ryan, C.G.; Bolotin, H.H.

1981-01-01

The velocity-dependence of the transient hyperfine magnetic field acting at nuclei of 196 Pt ions rapidly recoiling through thin magnetized Fe was investigated at a number of recoil velocities. The state of interest (2 1 + ) was populated by Coulomb excitation using beams of 80- and 120-MeV 32 S and 150- and 220-MeV 58 Ni ions. The 2 1 + →0 1 + γ-ray angular distribution precession measurements were carried out in coincidence with backscattered projectiles. From these results, the strength of the transient field acting on Pt ions recoiling through magnetized Fe with average velocities in the extended range 2.14<=v/vsub(o)<=4.82 (vsub(o) = c/137) was found to be consistent with a linear velocity dependence and to be incompatible with the specific vsup(0.45+-0.18) dependence which has been previously reported to account well for all ions in the mass range from oxygen through samarium. This seemingly singular behaviour for Pt and other ions in the Pt mass vicinity is discussed

Measurement and analysis of excitation functions in 16O + 103Rh system in the excitation energy range ≅ 2-4 MeV/A

International Nuclear Information System (INIS)

Singh, Devendra P.; Unnati; Sharma, Manoj Kumar; Singh, Pushpendra P.; Singh, B.P.; Prasad, R.; Gupta, Sunita; Rakesh Kumar; Bhardwaj, H.D.

2006-01-01

In the present work, excitation functions for seven evaporation residues (ERs) produced via complete fusion and incomplete fusion processes in 16 O + 103 Rh system have been measured in the energy range ≅ 47-85 MeV, using recoil catcher technique followed by off-line gamma-ray spectrometry. Comparison of the experimental data with statistical model based computer code PACE 2 revealed dominance of incomplete fusion in reactions involving alpha-emission channels. To the best of our knowledge these reactions are being reported for the first time

Scintillation efficiency measurement of Na recoils in NaI(Tl) below the DAMA/LIBRA energy threshold

Energy Technology Data Exchange (ETDEWEB)

Xu, Jingke; Shields, Emily; Calaprice, Frank; Westerdale, Shawn; Froborg, Francis; Suerfu, Burkhant; Alexander, Thomas; Aprahamian, Ani; Back, Henning O.; Casarella, Clark; Fang, Xiao; Gupta, Yogesh K.; Ianni, Aldo; Lamere, Edward; Lippincott, W. Hugh; Liu, Qian; Lyons, Stephanie; Siegl, Kevin; Smith, Mallory; Tan, Wanpeng; Kolk, Bryant Vande

2015-07-01

The dark matter interpretation of the DAMA modulation signal depends on the NaI(Tl) scintillation efficiency of nuclear recoils. Previous measurements for Na recoils have large discrepancies, especially in the DAMA/LIBRA modulation energy region. We report a quenching effect measurement of Na recoils in NaI(Tl) from 3 to 52 keVnr, covering the whole DAMA/LIBRA energy region for dark matter-Na scattering interpretations. By using a low-energy, pulsed neutron beam, a double time-of-flight technique, and pulse-shape discrimination methods, we obtained the most accurate measurement of this kind for NaI(Tl) to date. The results differ significantly from the DAMA reported values at low energies but fall between the other previous measurements. We present the implications of the new quenching results for the dark matter interpretation of the DAMA modulation signal.

Fabrication and testing of the recoil mass spectrometer at Bombay ...

Indian Academy of Sciences (India)

A recoil mass spectrometer (RMS) has been designed, fabricated and installed ... first order and only mass dispersion is obtained at the focal plane of the ... more details, like, the specifications and a typical beam profile through the ... Further experiments are now in progress to characterize the spectrometer, i.e., to measure.

Experimental studies of the formation and decay of hot nuclei

International Nuclear Information System (INIS)

Nifenecker, H.; Blachot, J.; Crancon, J.; Gizon, A.; Lleres, A.

1985-06-01

In the following we shall report on a number of measurements made with different projectiles ranging from 12 C to 40 Ar. In most cases the target was 124 Sn. In this case the reported results were obtained by off line γ counting of series of catchers allowing mass and velocity measurements of the quasi compound or quasi target recoils 11 . We shall also refer to some other results using conventional counter techniques and either lightersup(12,13) or heavier targetssup(14,15,16). We shall first examine the cross section for quasi fusion. We shall then adress the question of the limit of momentum transfer and that of the inference of excitation energies from recoil energies. Finally we discuss the possible observation of a threshold in the excitation energy that nuclei can support without breaking apart

Modeling and Measurement of 39Ar Recoil Loss From Biotite as a Function of Grain Dimensions

Science.gov (United States)

Paine, J. H.; Nomade, S.; Renne, P. R.

2004-12-01

The call for age measurements with less than 1 per mil error puts a demand upon geochronologists to be aware of and quantify a number of problems which were previously negligible. One such factor is 39Ar recoil loss during sample irradiation, a phenomenon which is widely assumed to affect only unusually small crystals having exceptionally high surface/volume ratios. This phenomenon has important implications for thermochronologic studies seeking to exploit a range of closure temperatures arising from variable diffusion radii. Our study focuses on biotite, in which spatial isotope distributions cannot be reliably recovered by stepwise heating and which therefore lack recoil-diagnostic age spectrum behavior. Previous work by Renne et al. [Application of a deuteron-deuteron (D-D) neutron generator to 40Ar/39Ar geochronology, Applied Radiation and Isotopes, in press] used the SRIM code to calculate a ˜20% 39Ar recoil loss from the outermost 0.25 μ m of an infinite slab of phyllosillicate. This result is applied to measured grains of the biotite standard GA1550, a hypabyssal granite from the Mount Dromedary Complex, Australia. We measure the thickness and surface area of 166 grains and approximate the shape of each grain as a cylinder. Grain thickness ranges from 3 to 210 μ m, with an average grain radius of 350 μ m. We predict the amount of 39Ar recoil loss from each grain, finding an expected age error >0.1 % for grains thinner than 150 μ m, a >1% error for grain less than 10 μ m thick, and up to a 3% error for grains less than 3 μ m thick. These modeling results will be tested by analysis of the measured grains after irradiation in the Oregon State University TRIGA reactor. It is important to either account for 39Ar loss in thin biotite grains, or use sufficiently thick ones so that recoil loss is negligible. Our results indicate that only biotite grains thicker than 150 μ m should be used for neutron fluence monitoring in order to avoid bias greater than the

The morphology of collision cascades as a function of recoil energy

International Nuclear Information System (INIS)

Heinisch, H.L.; Singh, B.N.

1989-09-01

An analytical method based on defect densities has been devised to determine the threshold energies for subcascade formation in computer simulated collision cascades. Cascades generated with the binary collision code MARLOWE in Al, Cu, Ag, Au, Fe, Mo and W were analyzed to determine the threshold energy for subcascade formation, the number of subcascades per recoil per unit energy and the average spacing of subcascades. Compared on the basis of reduced damage energy, metals of the same crystal structure have subcascade thresholds at the same reduced energy. The number of subcascades per unit reduced damage energy is about the same for metals of the same crystal structure, and the average spacing of subcascades is about the same in units of lattice parameters. Comparisons between subcascade threshold energies and average recoil energies in fission and fusion neutron environments show the spectral sensitivity of the formation of subcascades

Development of a digital trigger system to identify recoil protons at COMPASS-II

Energy Technology Data Exchange (ETDEWEB)

Buechele, Maximilian; Fischer, Horst; Gorzellik, Matthias; Grussenmeyer, Tobias; Herrmann, Florian; Joerg, Philipp; Koenigsmann, Kay; Kremser, Paul; Schopferer, Sebastian [Albert-Ludwigs-Universitaet Freiburg (Germany)

2014-07-01

The GANDALF framework has been developed to deliver a high precision, high performance detector readout and trigger system for particle physics experiments such as the COMPASS-II experiment at CERN. Combining the high performance pulse digitization and feature extraction capabilities of twelve GANDALF modules, each comprising a Virtex-5 SX95T, with the strong computation power of a Virtex-6 SX315T FGPA operated on the TIGER module, we present a digital trigger system for a recoil proton detector. The trigger system was setup and commissioned successfully during a data taking period in 2012. It was mainly used for the calibration of the recoil proton detector and in tagging mode to identify proton tracks online.

A proton-recoil neutron spectrometer for time-dependent ion temperatures on the National Ignition Facility

International Nuclear Information System (INIS)

Murphy, T.J.

1995-01-01

Ion temperatures from inertial confinement fusion targets are usually determined by measuring the Doppler broadening of the neutron spectrum using the time-of-flight method. Measurement systems are generally designed so that the contribution of the duration of neutron production (∼100 ps) to the width of the neutron signal is negligible. This precludes the possibility of time-dependent ion temperature. If, however, one could measure the neutron energy and arrival time at a detector independently, then time-dependent neutron spectra could be obtained, and ion temperature information deduced. A concept utilizing a proton-recoil neutron spectrometer has been developed in which recoil protons from a small plastic foil are measured. From the energy, arrival time, and recoil angle of the recoil proton, the birth time and energy of the incident neutron can be deduced. The sensitivity of the system is low, but the higher anticipated neutron yields from the proposed National Ignition Facility may make the technique feasible. Large scintillator arrays currently in use on the Nova facility for neutron spectral measurements consist of ∼1,000 channels and detect between 50 and 500 counts for typical time-integrated data. Time-dependent results would then require about an order of magnitude larger system. Key issues for making this system feasible will be keeping the cost per channel low while allowing adequately time (∼ 50 ps), energy (20 keV), and angular resolution (2 mrad) for each of the proton detectors

The HERMES recoil detector. Particle identification and determination of detector efficiency of the scintillating fiber tracker

Energy Technology Data Exchange (ETDEWEB)

Lu, Xianguo

2009-11-15

HERMES is a fixed target experiment using the HERA 27.6 GeV polarized electron/positron beams. With the polarized beams and its gas targets, which can be highly polarized, HERMES is dedicated to study the nucleon spin structure. One of its current physics programs is to measure deeply virtual Compton scattering (DVCS). In order to detect the recoiling proton the Recoil Detector was installed in the target region in the winter of 2005, taking data until the HERA-shutdown in the summer of 2007. The Recoil Detector measured energy loss of the traversing particles with its sub-detectors, including the silicon strip detector and the scintillating fiber tracker. This enables particle identification for protons and pions. In this work a systematic particle identification procedure is developed, whose performance is quantified. Another aspect of this work is the determination of the detector efficiency of the scintillating fiber tracker. (orig.)

First β-ν correlation measurement from the recoil-energy spectrum of Penning trapped Ar35 ions

Science.gov (United States)

Van Gorp, S.; Breitenfeldt, M.; Tandecki, M.; Beck, M.; Finlay, P.; Friedag, P.; Glück, F.; Herlert, A.; Kozlov, V.; Porobic, T.; Soti, G.; Traykov, E.; Wauters, F.; Weinheimer, Ch.; Zákoucký, D.; Severijns, N.

2014-08-01

We demonstrate a novel method to search for physics beyond the standard model by determining the β-ν angular correlation from the recoil-ion energy distribution after β decay of ions stored in a Penning trap. This recoil-ion energy distribution is measured with a retardation spectrometer. The unique combination of the spectrometer with a Penning trap provides a number of advantages, e.g., a high recoil-ion count rate and low sensitivity to the initial position and velocity distribution of the ions and completely different sources of systematic errors compared to other state-of-the-art experiments. Results of a first measurement with the isotope Ar35 are presented. Although currently at limited precision, we show that a statistical precision of about 0.5% is achievable with this unique method, thereby opening up the possibility of contributing to state-of-the-art searches for exotic currents in weak interactions.

Origin of open recoil curves in L1_0-A1 FePt exchange coupled nanocomposite thin film

International Nuclear Information System (INIS)

Goyal, Rajan; Kapoor, Akanksha; Lamba, S.; Annapoorni, S.

2016-01-01

Mixed phase FePt systems with intergranular coupling may be looked upon as natural exchange spring systems. The coupling strength between the soft and hard phase in these systems can be analyzed using recoil curves. However, the origin of open recoil curves depicting the breakdown of exchange coupling or anisotropy variation in hard phase is still an ambiguity and requires an in-depth analysis. In order to investigate this, an analysis of the recoil curves for L1_0–A1 FePt nanocomposite thin films of varying thickness have been performed. The switching field distribution reveals that the maximum of openness of recoil curve is directly proportional to the amount of uncoupled soft phase present in the system. The coupling between the hard and soft phase is also found to increase with the thickness of the film. Monte Carlo simulations on a model three dimensional array of interacting nanomagnetic grains provide further insight into the effect of inter granular exchange interactions between the soft and hard phases. - Highlights: • L1_0-A1 FePt nanocomposites thin films of different thickness have been fabricated by DC sputtering. • Hysteresis curve measurements exhibit perfect single phase (L1_0) like behavior for thicker films. • SFD reveals that the openness of recoil curves is directly linked with the amount of uncoupled soft (A1) phase. • Monte Carlo simulation predicts that the extent of exchange interaction increases with thickness of the film.

Measurements of isomers at the FRS ion catcher

Energy Technology Data Exchange (ETDEWEB)

Hornung, Christine [Justus-Liebig Universitaet Giessen (Germany); Collaboration: FRS Ion Catcher-Collaboration

2016-07-01

Projectile fragmentation and fission reactions at in-flight facilities are important production mechanisms to access short-lived exotic nuclei. It is a challenge to describe the angular momentum distribution after the collision of relativistic nuclei. This can be experimentally accessed by measuring the population of isomeric states. Isomeric ratios and excitation energies of isomers of short-lived exotic nuclei can be determined at the FRS Ion Catcher at GSI. At the FRS, projectile and fission fragments are produced at relativistic energies, separated in-flight and range-focused. They are slowed down and thermalized in a cryogenic stopping cell. In a multi-purpose RFQ beamline alpha spectroscopy can be performed. Alternatively the ions can be transported to a multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS), where masses of the ground and isomeric states can be measured simultaneously with high resolving power. The MR-TOF-MS can also be used to spatially separate the ions in order to provide isomerically clean ion beams. During a recent experiment isomer-to-ground state ratios and excitation energies of uranium projectile and fission fragments produced at 1 GeV/u were measured. The ratios, measured with the MR-TOF-MS, were verified by alpha spectroscopy. Furthermore the ratios were compared to calculations based on an abrasion-ablation model of fragmentation.

Coincident Auger electron and recoil ion momentum spectroscopy for low-energy ion-atom collisions

International Nuclear Information System (INIS)

Laurent, G.; Tarisien, M.; Flechard, X.; Jardin, P.; Guillaume, L.; Sobocinski, P.; Adoui, L.; Bordenave-Montesquieu, A.; Bordenave-Montesquieu, D.; Chesnel, J.-Y.; Fremont, F.; Hennecart, D.; Lienard, E.; Maunoury, L.; Moretto-Capelle, P.; Cassimi, A.

2003-01-01

The recoil ion momentum spectroscopy (RIMS) method combined with the detection of Auger electrons has been used successfully to analyse double electron capture following O 6+ + He collisions at low impact velocities. Although RIMS and Auger spectroscopies are known to be efficient tools to obtain details on the primary processes occurring during the collision, the conjunction of both techniques provides new insights on the electron capture process. In the present experiment, triple coincidence detection of the scattered projectile, the target recoil ion and the Auger electron allows for a precise identification of the doubly excited states O 4+ (1s 2 nln ' l ' ) populated after double electron-capture events

Test of Magnetic Rotation near the band head in ^197,198Pb

Science.gov (United States)

Krücken, R.; Clark, R. M.; Deleplanque, M. A.; Diamond, R. M.; Fallon, P.; Macchiavelli, A. O.; Lee, I. Y.; Schmid, G. J.; Stephens, F. S.; Vetter, K.; Dewald, A.; Peusquens, R.; von Brentano, P.; Baldsiefen, G.; Chmel, S.; Hübel, H.; Becker, J. A.; Bernstein, L. A.; Hauschild, K.

1998-04-01

The concept of magnetic rotation is tested near the band head of shears-bands in ^197,198Pb by means of a lifetime experiment with the recoil distance method (RDM). The experiment was performed using the Gammasphere array in conjunction with the Cologne Plunger. The B(M1) values extracted from the measured lifetimes can prove the applicability of the concept of magnetic rotation for the states near the band head of these shears bands. The RDM results are compared with tilted axis cranking and shell model calculations. Furthermore the results will be used to test earlier DSAM lifetime measurements for states at higher spins. Preliminary results of this topic will be presented. This work is supported by DOE grant numbers DE-AC03-76SF00098 (LBNL), DE-FG02-91ER40609 (Yale), W-7405-ENG-48 (LLNL) and by the German BMBF for Cologne (No. 06 OK 668) and Bonn.

Sizing of "Mother Ship and Catcher" Missions for LEO Small Debris and for GEO Large Object Capture

Science.gov (United States)

Bacon, John B.

2009-01-01

Most LEO debris lies in a limited number of inclination "bands" associated with specific useful orbits. Objects in such narrow inclination bands have all possible Right Ascensions of Ascending Node (RAANs), creating a different orbit plane for nearly every piece of debris. However, a low-orbiting satellite will always phase in RAAN faster than debris objects in higher orbits at the same inclination, potentially solving the problem. Such a low-orbiting base can serve as a "mother ship" that can tend and then send small, disposable common individual catcher/deboost devices--one for each debris object--as the facility drifts into the same RAAN as each higher object. The dV necessary to catch highly-eccentric orbit debris in the center of the band alternatively allows the capture of less-eccentric debris in a wider inclination range around the center. It is demonstrated that most LEO hazardous debris can be removed from orbit in three years, using a single LEO launch of one mother ship--with its onboard magazine of freeflying low-tech catchers--into each of ten identified bands, with second or potentially third launches into only the three highest-inclination bands. The nearly 1000 objects near the geostationary orbit present special challenges in mass, maneuverability, and ultimate disposal options, leading to a dramatically different architecture and technology suite than the LEO solution. It is shown that the entire population of near-GEO derelict objects can be gathered and tethered together within a 3 year period for future scrap-yard operations using achievable technologies and only two earth launches.

In-beam studies of {sup 98}Cd and {sup 102}Sn

Energy Technology Data Exchange (ETDEWEB)

Lipoglavsek, M. [Uppsala Univ. (Sweden)]|[J. Stefan Institute, Ljubljana (Slovenia); Gorska, M.; Schubart, R. [GSI, Darmstadt (Germany)] [and others

1996-12-31

For the first time excited states of the neutron deficient nuclei {sup 98}Cd and {sup 102}Sn were identified using in-beam spectroscopy following fusion evaporation reactions. Half lives of long lived isomeric states in both nuclei were also measured. Due to very low cross sections for producing {sup 98}Cd and {sup 102}Sn with stable beams and targets, a special detector setup utilizing NORDBALL ancillary detectors and a recoil catcher device was used. High {gamma}-ray detection efficiency was achieved with two EUROBALL Ge cluster detectors.

Mass distribution in 20Ne+232Th reaction

International Nuclear Information System (INIS)

Sodaye, Suparna; Tripathi, R.; Sudarshan, K.

2011-01-01

Mass distribution was measured in 20 Ne+ 232 Th reaction at E lab =145 MeV using recoil catcher technique followed by off-line gamma-ray spectrometry. Significant contribution from transfer fission was observed in the yield of comparatively neutron rich fission products. The variance of mass distribution for complete fusion fission, obtained by excluding neutron rich fission products, was observed to be consistent with the values reported in literature for similar reaction systems which showed a deviation from the systematics obtained using random neck rupture and liquid drop model. (author)

Recoil halogen reactions in liquid and frozen aqueous solutions of biomolecules

International Nuclear Information System (INIS)

Arsenault, L.J.; Blotcky, A.J.; Firouzbakht, M.L.; Rack, E.P.; Nebraska Univ., Omaha

1982-01-01

Reactions of recoil 38 Cl, 80 Br and 128 I have been studied in crystalline systems of 5-halouracil, 5-halo-2'-deoxyuridine and 5-halouridine as well as liquid and frozen aqueous solutions of these halogenated biomolecules. In all systems expect crystalline 5-iuodouracil the major product was the radio-labelled halide ion. There was no evidence for other halogen inorganic species. The major labelled organic product was the parent molecule. A recoil atom tracer technique was developed to acquire site information of the biomolecule solutes in the liquid and frozen aqueous systems. For all liquid and frozen aqueous systems, the halogenated biomolecules tended to aggregate. For liquid systems, the tendency for aggregation diminished as the solute concentration approached zero, where the probable state of the solute approached a monomolecular dispersion. Unlike the liquid state, the frozen ice lattice demonstated a ''caging effect'' for the solute aggregates which resulted in constant product yields over the whole concentration range. (orig.)

A study of etching model of alpha-recoil tracks in biotite

International Nuclear Information System (INIS)

Dong Jinquan; Yuan Wanming; Wang Shicheng; Fan Qicheng

2005-01-01

Like fission-track dating, alpha-recoil track (ART) dating is based on the accumulation of nuclear particles that the released from natural radioactivity and produce etchable tracks in solids. ARTs are formed during the alpha-decay of uranium and thorium as well as of their daughter nuclei. When emitting an alpha-particle, the heavy remaining nucleus recoils 30-40 nm, leaving behind a trail of radiation damage. Through etching the ART tracks become visible with the aid of an interference phase-contrast microscope. Under the presupposition that all tracks are preserved since the formation of a sample their total number is a measure of the sample's age. The research for etching model is to accurately determine ART volume density, i.e., the number of ARTs per unit volume. The volume density of many dots in many layers may be determined on a sample using this etching model, and as decreasing the error and increasing the accuracy. (authors)

Neutron electric form factor via recoil polarimetry

International Nuclear Information System (INIS)

Richard Madey; Andrei Semenov; Simon Taylor; Aram Aghalaryan; Erick Crouse; Glen MacLachlan; Bradley Plaster; Shigeyuki Tajima; William Tireman; Chenyu Yan; Abdellah Ahmidouch; Brian Anderson; Razmik Asaturyan; O. Baker; Alan Baldwin; Herbert Breuer; Roger Carlini; Michael Christy; Steve Churchwell; Leon Cole; Samuel Danagoulian; Donal Day; Mostafa Elaasar; Rolf Ent; Manouchehr Farkhondeh; Howard Fenker; John Finn; Liping Gan; Kenneth Garrow; Paul Gueye; Calvin Howell; Bitao Hu; Mark Jones; James Kelly; Cynthia Keppel; Mahbubul Khandaker; Wooyoung Kim; Stanley Kowalski; Allison Lung; David Mack; D. Manley; Pete Markowitz; Joseph Mitchell; Hamlet Mkrtchyan; Allena Opper; Charles Perdrisat; Vina Punjabi; Brian Raue; Tilmann Reichelt; Joerg Reinhold; Julie Roche; Yoshinori Sato; Wonick Seo; Neven Simicevic; Gregory Smith; Samuel Stepanyan; Vardan Tadevosyan; Liguang Tang; Paul Ulmer; William Vulcan; John Watson; Steven Wells; Frank Wesselmann; Stephen Wood; Chen Yan; Seunghoon Yang; Lulin Yuan; Wei-Ming Zhang; Hong Guo Zhu; Xiaofeng Zhu

2003-01-01

The ratio of the electric to the magnetic form factor of the neutron, G En /G Mn , was measured via recoil polarimetry from the quasielastic d((pol-e),e(prime)(pol-n)p) reaction at three values of Q 2 [viz., 0.45, 1.15 and 1.47 (GeV/c) 2 ] in Hall C of the Thomas Jefferson National Accelerator Facility. Preliminary data indicate that G En follows the Galster parameterization up to Q 2 = 1.15 (GeV/c) 2 and appears to rise above the Galster parameterization at Q 2 = 1.47 (GeV/c) 2

Multivariate analysis method for energy calibration and improved mass assignment in recoil spectrometry

International Nuclear Information System (INIS)

El Bouanani, Mohamed; Hult, Mikael; Persson, Leif; Swietlicki, Erik; Andersson, Margaretha; Oestling, Mikael; Lundberg, Nils; Zaring, Carina; Cohen, D.D.; Dytlewski, Nick; Johnston, P.N.; Walker, S.R.; Bubb, I.F.; Whitlow, H.J.

1994-01-01

Heavy ion recoil spectrometry is rapidly becoming a well established analysis method, but the associated data analysis processing is still not well developed. The pronounced nonlinear response of silicon detectors for heavy ions leads to serious limitation and complication in mass gating, which is the principal factor in obtaining energy spectra with minimal cross talk between elements. To overcome the above limitation, a simple empirical formula with an associated multiple regression method is proposed for the absolute energy calibration of the time of flight-energy dispersive detector telescope used in recoil spectrometry. A radical improvement in mass assignment was realized, which allows a more accurate and improved depth profiling with the important feature of making the data processing much easier. ((orig.))

Mixing of phosphorus and antimony ions in silicon by recoil implantation

International Nuclear Information System (INIS)

Kwok, H.L.; Lam, Y.W.; Wong, S.P.; Poon, M.C.

1986-01-01

The effects of mixing phosphorus and antimony ions in silicon by recoil implantation were examined. The electrical properties after ion mixing were investigated, and the results were compared with those obtained using other techniques. Different degrees of activation were also studied, by investigating the annealing behaviour. (U.K.)

Half-life and mass measurement of the short-lived {sup 215}Po isotope (1.78 ms) at the FRS ion catcher

Energy Technology Data Exchange (ETDEWEB)

Rink, Ann-Kathrin; Bergmann, Julian; Ebert, Jens; Hornung, Christine; Miskun, Ivan; Reiter, Moritz P. [Justus-Liebig Universitaet Giessen (Germany); Ayet San Andres, Samuel; Dickel, Timo; Plass, Wolfgang R.; Scheidenberger, Christoph [Justus-Liebig Universitaet Giessen (Germany); GSI, Darmstadt (Germany); Geissel, Hans; Purushothaman, Sivaji [GSI, Darmstadt (Germany)

2016-07-01

At the Low-Energy Branch (LEB) of the Super-FRS at FAIR, precision experiments with exotic nuclei will be performed using ion traps and lasers. The nuclei will be produced at relativistic energies, slowed down, thermalised in a cryogenic stopping cell (CSC) and made available to various experiments. The thermalisation is a challenging task because of the large energy straggling of the nuclei after production, which requires a stopping cell with large areal densities. Also, the process needs to be performed on a millisecond time scale in order to give access to short-lived nuclides. This method has already been successfully applied at the FRS Ion Catcher at GSI using a prototype CSC. Recently the potential of the method has been demonstrated by the mass and half-life measurement of the {sup 215}Po nuclide with a half-life of 1.78 ms only. The multiple-reflection time-of-flight mass spectrometer at the FRS Ion Catcher has been used to determine the mass to a sub-ppm accuracy and to provide a mass-selected beam for alpha spectroscopy. Furthermore, experiments have been performed with the prototype CSC in order to test novel concepts to be used with the final version of the CSC for the LEB.

Kinematic separation and mass analysis of heavy recoiling nuclei

International Nuclear Information System (INIS)

Oganesyan, Yu.Ts.; Eremin, A.V.; Belozerov, A.V.

2002-01-01

Within the past twelve years, the recoil separator VASSILISSA has been used for investigation of evaporation residues produced in heavy-ion induced complete-fusion reactions. In the course of the experimental work in the region of the elements with 92 ≤ Z ≤ 94, fourteen new isotopes have been identified by the parent-daughter correlations. The study of the decay properties and formation cross sections of the isotopes of elements 110, 112, and 114 was performed with the use of the high intensity 48 Ca beams; 232 Th, 238 U and 242 Pu targets were used in the experiments. At the beam energies corresponding to the calculated cross-section maxima of the 3n evaporation channels, the isotopes 277 110, 283 112, and 287 114 were produced and identified. For further experiments aimed at the synthesis of the superheavy element isotopes (Z ≥ 110) with the intensive 48 Ca extracted beams, the improvements in the ion optical system of the separator and of the focal plane detector system have been made. As a result, for heavy recoiling nuclei with masses A ∼ 250, the mass resolution of about 2.5 % was achieved with a good energy and position resolutions of the focal plane detectors

Origin of open recoil curves in L1{sub 0}-A1 FePt exchange coupled nanocomposite thin film

Energy Technology Data Exchange (ETDEWEB)

Goyal, Rajan [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India); Kapoor, Akanksha [M. Tech Nanoscience and Nanotechnology, University of Delhi, Delhi 110007 (India); Lamba, S. [School of Sciences, Indira Gandhi National Open University, New Delhi 110068 (India); Annapoorni, S., E-mail: annapoornis@yahoo.co.in [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India)

2016-11-15

Mixed phase FePt systems with intergranular coupling may be looked upon as natural exchange spring systems. The coupling strength between the soft and hard phase in these systems can be analyzed using recoil curves. However, the origin of open recoil curves depicting the breakdown of exchange coupling or anisotropy variation in hard phase is still an ambiguity and requires an in-depth analysis. In order to investigate this, an analysis of the recoil curves for L1{sub 0}–A1 FePt nanocomposite thin films of varying thickness have been performed. The switching field distribution reveals that the maximum of openness of recoil curve is directly proportional to the amount of uncoupled soft phase present in the system. The coupling between the hard and soft phase is also found to increase with the thickness of the film. Monte Carlo simulations on a model three dimensional array of interacting nanomagnetic grains provide further insight into the effect of inter granular exchange interactions between the soft and hard phases. - Highlights: • L1{sub 0}-A1 FePt nanocomposites thin films of different thickness have been fabricated by DC sputtering. • Hysteresis curve measurements exhibit perfect single phase (L1{sub 0}) like behavior for thicker films. • SFD reveals that the openness of recoil curves is directly linked with the amount of uncoupled soft (A1) phase. • Monte Carlo simulation predicts that the extent of exchange interaction increases with thickness of the film.

Habits and customs of crab catchers in southern Bahia, Brazil.

Science.gov (United States)

Firmo, Angélica M S; Tognella, Mônica M P; Tenório, Gabrielle D; Barboza, Raynner R D; Alves, Rômulo R N

2017-08-23

Brazilian mangrove forests are widely distributed along the coast and exploited by groups of people with customs and habits as diverse as the biology of the mangrove ecosystems. This study identifies different methods of extracting crabs that inhabit the mangrove belts; some of these activities, such as catching individual crabs by hand, are aimed at maintaining natural stocks of this species in Mucuri (south Bahia), Brazil. In the studied community, illegal hunting activities that violate Brazilian legislation limiting the use of tangle-netting in mangrove ecosystem were observed. According to our observations, fishermen, to catch individual crabs, use the tangle-netting technique seeking to increase income and are from families that have no tradition of extraction. This analysis leads us to conclude that catchers from economically marginalised social groups enter mangroves for purposes of survival rather than for purposes of subsistence, because the catching by tangle-netting is a predatory technique. Tangle-netting  technique increase caught but also increases their mortality rate. We emphasise that traditional catching methods are unique to Brazil and that manual capturing of crab should be preserved through public policies aimed at maintaining the crab population.

Range calculations for spallation recoils in ThF4 by use of the computer code 'Marlowe'

International Nuclear Information System (INIS)

Westmeier, W.; Roessler, K.

1978-12-01

The determination of cross sections of spallation reactions requires a knowledge of the target thickness since only the products recoiling from the target are measured and their yield depends on the range. The effective target thickness is a function of the projectile's Z, A and spallation recoil energy and, thus, varies for the individual products. The computer code MARLOWE was used to evaluate energy vs. range curves in the binary collisions approximation. The program was extended to the high energy regime taking into account the stripping of electrons from the projectile and the concomitant changes in the interaction potentials especially for the inelastic part of the collisions. A complementary computer program LATTIC was developed for the parameterization of the lattice description. This code enables the application of MARLOWE to target materials with complicated crystallographic structure. Test calculations for a series of projectile/target combinations showed a reasonable agreement with experimental recoil ranges of Pd, Ag, Os and Ir isotopes from proton induced spallation in Ag, In and Pb targets, respectively. MARLOWE was then applied to calculate product ranges of the 232 Th(p,spall)X-reaction in the ployatomic system ThF 4 . The calculated energy vs. range curves enabled the evaluation of the mean spallation recoil ranges for all possible products, e.g. 170.8 μg/cm 2 for 192 Tl, 115.2 μg/cm 2 for 208 At and 37.1 μg/cm 2 for 223 Ac. (orig.)

Detection of low momentum protons with the new HERMES recoil detector

Energy Technology Data Exchange (ETDEWEB)

Vilardi, Ignazio

2008-10-15

In this theis the recoil detector for the HERMES experiment at HERA is described. It consists of a silicon strip detector, a scintillating fiber tracker, and a photon detector for the {delta}{sup +} background rejection, all surrounded by a superconducting 1 Tesla solenoid. Results of cosmic ray tests are presented. (HSI)

Detection of low momentum protons with the new HERMES recoil detector

International Nuclear Information System (INIS)

Vilardi, Ignazio

2008-10-01

In this theis the recoil detector for the HERMES experiment at HERA is described. It consists of a silicon strip detector, a scintillating fiber tracker, and a photon detector for the Δ + background rejection, all surrounded by a superconducting 1 Tesla solenoid. Results of cosmic ray tests are presented. (HSI)

Recoil corrected bag model calculations for semileptonic weak decays

International Nuclear Information System (INIS)

Lie-Svendsen, Oe.; Hoegaasen, H.

1987-02-01

Recoil corrections to various model results for strangeness changing weak decay amplitudes have been developed. It is shown that the spurious reference frame dependence of earlier calculations is reduced. The second class currents are generally less important than obtained by calculations in the static approximation. Theoretical results are compared to observations. The agreement is quite good, although the values for the Cabibbo angle obtained by fits to the decay rates are somewhat to large

High energy neutron recoil scattering from liquid 4He

International Nuclear Information System (INIS)

Holt, R.S.; Needham, L.M.; Paoli, M.P.

1987-10-01

The neutron recoil scattering from liquid 4 He at 4.2 K and 1.6 K has been observed for a momentum transfer of 150 A -1 using the Electron Volt Spectrometer on the pulsed neutron source, ISIS. The experiment yielded mean atomic kinetic energy values = 14.8 +- 3 K at 4.2 K and = 14.6 +- 3.2 K at 1.6 K in good agreement with values obtained at lower momentum transfers. (author)

Coincident Auger electron and recoil ion momentum spectroscopy for low-energy ion-atom collisions

Energy Technology Data Exchange (ETDEWEB)

Laurent, G. E-mail: glaurent@ganil.fr; Tarisien, M.; Flechard, X.; Jardin, P.; Guillaume, L.; Sobocinski, P.; Adoui, L.; Bordenave-Montesquieu, A.; Bordenave-Montesquieu, D.; Chesnel, J.-Y.; Fremont, F.; Hennecart, D.; Lienard, E.; Maunoury, L.; Moretto-Capelle, P.; Cassimi, A

2003-05-01

The recoil ion momentum spectroscopy (RIMS) method combined with the detection of Auger electrons has been used successfully to analyse double electron capture following O{sup 6+} + He collisions at low impact velocities. Although RIMS and Auger spectroscopies are known to be efficient tools to obtain details on the primary processes occurring during the collision, the conjunction of both techniques provides new insights on the electron capture process. In the present experiment, triple coincidence detection of the scattered projectile, the target recoil ion and the Auger electron allows for a precise identification of the doubly excited states O{sup 4+} (1s{sup 2}nln{sup '}l{sup '}) populated after double electron-capture events.

Electromagnetic transition probabilities in the natural-parity rotational bands of 155,157Gd

International Nuclear Information System (INIS)

Kusakari, H.; Oshima, M.; Uchikura, A.; Sugawara, M.; Tomotani, A.; Ichikawa, S.; Iimura, H.; Morikawa, T.; Inamura, T.; Matsuzaki, M.

1992-01-01

The ground-state rotational bands of 155 Gd and 157 Gd have been investigated through multiple Coulomb excitation with beams of 240-MeV 58 Ni and 305-MeV 81 Br. Gamma-ray branchings and E2/M1 mixing ratios were determined by γ-ray angular-distribution measurement. Nuclear lifetimes of levels up to I=21/2 and 23/2 for 155,157 Gd, respectively, have been measured using the Doppler-shift recoil-distance method. The observed signature dependence of M1 transition rates was found to be inverted in relation to the quasiparticle energy splitting. The data are analyzed in terms of the cranking model

In-situ, real-time, studies of film growth processes using ion scattering and direct recoil spectroscopy techniques.

Energy Technology Data Exchange (ETDEWEB)

Smentkowski, V. S.

1999-04-22

Time-of-flight ion scattering and recoil spectroscopy (TOF-ISARS) enables the characterization of the composition and structure of surfaces with 1-2 monolayer specificity. It will be shown that surface analysis is possible at ambient pressures greater than 3 mTorr using TOF-ISARS techniques; allowing for real-time, in situ studies of film growth processes. TOF-ISARS comprises three analytical techniques: ion scattering spectroscopy (ISS), which detects the backscattered primary ion beam; direct recoil spectroscopy (DRS), which detects the surface species recoiled into the forward scattering direction; and mass spectroscopy of recoiled ions (MSRI), which is 3 variant of DRS capable of isotopic resolution for all surface species--including H and He. The advantages and limitations of each of these techniques will be discussed. The use of the three TOF-ISARS methods for real-time, in situ film growth studies at high ambient pressures will be illustrated. It will be shown that MSRI analysis is possible during sputter deposition. It will be also be demonstrated that the analyzer used for MSRI can also be used for time of flight secondary ion mass spectroscopy (TOF-SIMS) under high vacuum conditions. The use of a single analyzer to perform the complimentary surface analytical techniques of MSRI and SIMS is unique. The dwd functionality of the MSRI analyzer provides surface information not obtained when either MSRI or SIMS is used independently.

Chemical reactions of recoil atoms and thermal atoms of tritium with haloid benzenes

International Nuclear Information System (INIS)

Simirskij, Yu.N.; Firsova, L.P.

1978-01-01

Radiochemical yields have been determined for the products of substitution of hydrogen atoms and halides in Cl-, Br-, and I-benzenes with tritium atoms obtained during thermal dissociation of T 2 and with recoil atoms T arising in nuclear reaction 6 Li(n, P)T. It is shown that in the series of Cl-, Br-, and I-benzenes yields of the products of substitution of halides atoms with tritium grow, whereas those of hydrogen atom substitution change only little. The correlation nature of the yields of substitution products of halide atoms with tritium remains constant in a wide range of the initial kinetic energies of T atoms for the recoil atoms with E 0 =2.7 MeV and for the completely thermolized atoms during thermal dissociation of T 2

Recoil and conversion electron considerations of the {sup 166}Dy/{sup 166}Ho in vivo generator

Energy Technology Data Exchange (ETDEWEB)

Zeevaart, J.R. [North-West Univ., Mmabatho (South Africa). CARST; Szuecs, Z. [Nesca (South African Nuclear Energy Corporation Ltd.), Pretoria (South Africa). Radiochemistry; Hungarian Academy of Sciences, Debrecen (Hungary). Inst. of Nuclear Research; Takacs, S.; Jarvis, N. [Hungarian Academy of Sciences, Debrecen (Hungary). Inst. of Nuclear Research; Jansen, D. [Nesca (South African Nuclear Energy Corporation Ltd.), Pretoria (South Africa). Radiochemistry

2012-07-01

The use of radionuclides as potential therapeutic radiopharmaceuticals is increasingly investigated. An important aspect is the delivery of the radionuclide to the target, i.e. the radionuclide is not lost from the chelating agent. For in vivo generators, it is not only the log K of complexation between the metal ion and the chelator that is important, but also whether the daughter radionuclide stays inside the chelator after decay of the parent radionuclide. In our previous work, we showed that the classical recoil effect is only applicable for decays with a Q value higher than 0.6 MeV (in the atomic mass range around 100). However, Zhernosekov et al. published a result for {sup 140}Nd/{sup 140}Pr (Q = 0.222 MeV) which indicated that > 95% of the daughter ({sup 140}Pr) was lost by a DOTA chelator upon decay of {sup 140}Nd. The authors ascribed this to the ''post-effect''. Their experiment was repeated with the {sup 166}Dy/{sup 166}Ho generator to ascertain whether our calculations were correct. It was found that 72% of the daughter ({sup 166}Ho) was liberated from the DOTA chelator, indicating that the 'post effect' does exist in contrast to our recoil calculations. Upon further investigation, we determined that one should not only consider recoil energy levels but also the mode of decay which was able to explain the partial recoil found for {sup 166}Dy/{sup 166}Ho. It is concluded for the {sup 166}Dy/{sup 166}Ho system that the low recoil energy of the daughter nucleus {sup 166}Ho is not a sufficient reason to rule out release of the nuclide from chelators. On the other hand, we found that the ratio of the {sup 166}Ho that gets released corresponds to the ratio of relaxation of Ho atoms via the Auger process. (orig.)

Direct mass measurements of light neutron-rich nuclei using fast recoil spectrometers

International Nuclear Information System (INIS)

Vieira, D.J.; Wouters, J.M.

1987-01-01

Extensive new mass measurement capabilities have evolved with the development of recoil spectrometers. In the Z = 3 to 9 neutron-rich region alone, 12 neutron-rich nuclei have been determined for the first time by the fast-recoil direct mass measurement method. A recent experiment using the TOFI spectrometer illustrates this technique. A systematic investigation of nuclei that lie along or near the neutron-drip line has provided a valuable first glimpse into the nuclear structure of such nuclei. No evidence for a large single-particle energy gap at N = 14 is observed; however, a change in the two-neutron separation model calculations, and is interpreted in terms of the smaller 1s/sub 1/2/ - 1s/sub 1/2/ interaction compared to that of the 0d/sub 5/2/ - 0d/sub 5/2/ neutron-neutron interaction. 18 refs., 7 figs., 1 tab

Emanation of /sup 232/U daughter products from submicrometer particles of uranium oxide and thorium dioxide by nuclear recoil and inert gas diffusion

Energy Technology Data Exchange (ETDEWEB)

Coombs, M.A.; Cuddihy, R.G. (Lovelace Biomedical and Environmental Research Inst., Albuquerque, NM (USA). Inhalation Toxicology Research Inst.)

1983-01-01

Emanation of /sup 232/U daughter products by nuclear recoil and inert gas diffusion from spherical, submicrometer particles of uranium oxide and thorium dioxide was studied. Monodisperse samples of particles containing 1% /sup 232/U and having physical diameters between 0.1 and 1 ..mu..m were used for the emanation measurements. Thorium-228 ions recoiling from the particles after alpha-decay of /sup 232/U were collected electrostatically on a recoil cathode. Radon-220 diffusing from the particles was swept by an airstream into a 4 l. chamber where the /sup 220/Rn daughters were collected on a second cathode. Mathematical models of radionuclide emanation from spherical particles were used to calculate the recoil range of /sup 228/Th and the diffusion coefficient of /sup 220/Rn in the particle matrix. A /sup 228/Th recoil range of 0.02 ..mu..m and a /sup 220/Rn diffusion coefficient of 3 x 10/sup -14/ cm/sup 2//sec were obtained in both uranium oxide and thorium dioxide particles.

Properties enhancement and recoil loop characteristics for hot deformed nanocrystalline NdFeB permanent magnets

International Nuclear Information System (INIS)

Liu, Z. W.; Huang, Y. L.; Hu, S. L.; Zhong, X. C.; Yu, H. Y.; Gao, X. X.

2013-01-01

Nanocrystalline NdFeB magnets were prepared by spark plasma sintering (SPS) and SPS followed by HD using melt spun ribbons as the starting materials. The microstructure of SPSed and HDed magnets were analyzed. The effects of process including temperature and compression ratio on the microstructure and properties were investigated. High magnetic properties were obtained in anisotropic HDed magnets. The combination of Zn and Dy additions was successfully employed to improve the coercivity and thermal stability of the SPSed magnets. Open recoil loops were found in these magnets with Nd-rich composition and without soft magnetic phase for the first time. The relationship between the recoil loops and microstructure for SPS and HD NdFeB magnets were investigated. The investigations showed that the magnetic properties of SPS+HDed magnets are related to the extent of the aggregation of Nd-rich phase, which was formed during HD due to existence of porosity in SPSed precursor. Large local demagnetization fields induced by the Nd-rich phase aggregation leads to the open loops and significantly reduced the coercivity. By reducing the recoil loop openness, the magnetic properties of HDed NdFeB magnets were successfully improved. (author)

Energy Reduction Multipath Routing Protocol for MANET Using Recoil Technique

Directory of Open Access Journals (Sweden)

Rakesh Kumar Sahu

2018-04-01

Full Text Available In Mobile Ad-hoc networks (MANET, power conservation and utilization is an acute problem and has received significant attention from academics and industry in recent years. Nodes in MANET function on battery power, which is a rare and limited energy resource. Hence, its conservation and utilization should be done judiciously for the effective functioning of the network. In this paper, a novel protocol namely Energy Reduction Multipath Routing Protocol for MANET using Recoil Technique (AOMDV-ER is proposed, which conserves the energy along with optimal network lifetime, routing overhead, packet delivery ratio and throughput. It performs better than any other AODV based algorithms, as in AOMDV-ER the nodes transmit packets to their destination smartly by using a varying recoil off time technique based on their geographical location. This concept reduces the number of transmissions, which results in the improvement of network lifetime. In addition, the local level route maintenance reduces the additional routing overhead. Lastly, the prediction based link lifetime of each node is estimated which helps in reducing the packet loss in the network. This protocol has three subparts: an optimal route discovery algorithm amalgamation with the residual energy and distance mechanism; a coordinated recoiled nodes algorithm which eliminates the number of transmissions in order to reduces the data redundancy, traffic redundant, routing overhead, end to end delay and enhance the network lifetime; and a last link reckoning and route maintenance algorithm to improve the packet delivery ratio and link stability in the network. The experimental results show that the AOMDV-ER protocol save at least 16% energy consumption, 12% reduction in routing overhead, significant achievement in network lifetime and packet delivery ratio than Ad hoc on demand multipath distance vector routing protocol (AOMDV, Ad hoc on demand multipath distance vector routing protocol life

High-energy elastic recoil detection heavy ions for light element analysis

International Nuclear Information System (INIS)

Goppelt-Langer, P.; Yamamoto, S.; Takeshita, H.; Aoki, Y.; Naramoto, H.

1994-01-01

The detection of light and medium heavy elements in not homogeneous solids is a severe problem in ion beam analysis. Heavy elements can be detected by the well established Rutherford backscattering technique (RBS). In a homogeneous host material most impurities can be easily analyzed by secondary ion mass spectroscopy (SIMS). Some isotopes ( 3 He, 6 Li, 10 B) can be measured by nuclear reaction analysis (NRA) using thermal neutrons inducing (n, p) or (n, α) reactions. Others can be detected by energetic ion beams by nuclear reactions (e.g. 15 N( 1 H, αγ) 12 C for analysis of hydrogen). A high content of H, D or T can be also determined by elastic recoil detection using an energetic He beam. The latter technique has been developed to a universal method for detection of light and heavy elements in any target, using a high energetic heavy ion beam and a detector system, which is able to identify the recoils and delivers energy and position of the particles. (author)

Black hole radiation in the brane world and the recoil effect

International Nuclear Information System (INIS)

Frolov, Valeri; Stojkovic, Dejan

2002-01-01

A black hole attached to a brane in a higher-dimensional space emitting quanta into the bulk may leave the brane as a result of a recoil. We study this effect. We consider black holes which have a size much smaller than the characteristic size of extra dimensions. Such a black hole can be effectively described as a massive particle with internal degrees of freedom. We consider an interaction of such particles with a scalar massless field and prove that for a special choice of the coupling constant describing the transition of the particle to a state with smaller mass the probability of massless quanta emission takes the form identical to the probability of the black hole emission. Using this model we calculate the probability for a black hole to leave the brane and study its properties. The discussed recoil effect implies that, for black holes which might be created in the interaction of high energy particles in colliders, the thermal emission of the formed black hole could be terminated and the energy nonconservation can be observed in brane experiments

Boiling crisis as inhibition of bubble detachment by the vapor recoil force

International Nuclear Information System (INIS)

Nikolayev, V.S.; Beysens, D.; Garrabos, Y.

2004-01-01

Boiling crisis is a transition between nucleate and film boiling. In this communication we present a physical model of the boiling crisis based on the vapor recoil effect. Our numerical simulations of the thermally controlled bubble growth at high heat fluxes show how the bubble begins to spread over the heater thus forming a germ for the vapor film. The vapor recoil force not only causes the vapor spreading, it also creates a strong adhesion to the heater that prevents the bubble departure, thus favoring the further bubble spreading. Near the liquid-gas critical point, the bubble growth is very slow and allows the kinetics of the bubble spreading to be observed. Since the surface tension is very small in this regime, only microgravity conditions can preserve a convex bubble shape. Under such conditions, we observed an increase of the apparent contact angle and spreading of the dry spot under the bubble, thus confirming our model of the boiling crisis. (authors)

D-Brane Recoil Mislays Information

CERN Document Server

Ellis, Jonathan Richard; Nanopoulos, Dimitri V

1998-01-01

We discuss the scattering of a light closed-string state off a $D$ brane, taking into account quantum recoil effects on the latter, which are described by a pair of logarithmic operators. The light-particle and $D$-brane subsystems may each be described by a world-sheet with an external source due to the interaction between them. This perturbs each subsystem away from criticality, which is compensated by dressing with a Liouville field whose zero mode we interpret as time. The resulting evolution equations for the $D$ brane and the closed string are of Fokker-Planck and modified quantum Liouville type, respectively. The apparent entropy of each subsystem increases as a result of the interaction between them, which we interpret as the loss of information resulting from non-observation of the other entangled subsystem. We speculate on the possible implications of these results for the propagation of closed strings through a dilute gas of virtual $D$ branes.

The G_E/G_M-ratio of the proton by recoil polarization measurement in e+parrow e'+p

Science.gov (United States)

Punjabi, Vina; Jones, Mark; Perdrisat, Charles F.; Quemener, Gilles

1998-10-01

The recently commissioned Hall A high resolution spectrometers (HRS) and the focal plane polarimeter (FPP) were used to obtain the ratio of the electric and magnetic form factors of the proton, G_E/G_M. This form factor ratio is proportional to the measured ratio of the transverse, P_t, to longitudinal, P_l, components of the recoiling proton polarization. The method takes advantage of the precession of the proton magnetic moment in the hadron HRS, which rotates the longitudinal polarization component into the plane of the FPP analyzer; this allows simultaneous measurement of both components of the polarization. The ratio P_t/P_l is independent of both the electron beam polarization and the polarimeter analyzing power. Most of the data were obtained with polarized beams of 100 μ A with polarization of ~ 0.39 incident on the 15 cm cell of the high power LH2 target. We will report the results for G_E/GM at several values of Q^2 between 0.5 and 3.5 GeV^2.

Model-independent evaluation of recoils channeling impact on visible energy spectra in dark matter particles crystalline detectors

International Nuclear Information System (INIS)

Dyuldya, S.V.; Bratchenko, M.I.

2012-01-01

Proposed is a direct method of Dark Matter crystalline scintillation detectors calibration by means of an atomistic molecular dynamics modeling of their responses to ∼10 keV recoil atoms. Simulations show that the recoils channeling exists in NaI lattice with probabilities of ∼5 - 15 %. It does not affect the mean values of quenching factors but gives rise to high visible energy spectral tails absent in disordered detectors. As a result, the lattice ordering manifests the ∼100 % effect on NaI(Tl) visible energy spectra at 2-6 keV window

Penetration of HEPA filters by alpha recoil aerosols

International Nuclear Information System (INIS)

McDowell, W.J.; Seeley, F.G.; Ryan, M.T.

1976-01-01

Tests at Oak Ridge National Laboratory confirmed that alpha-emitting particulate matter does penetrate high-efficiency filter medium, identical to that used in HEPA filters, much more effectively than do non-radioactive or beta-gamma active aerosols. Filter retention efficiencies drastically lower than the 99.97 percent quoted for ordinary particulate matter have been observed with 212 Pb, 253 Es, and 238 Pu sources, indicating that the phenomenon is common to all of these and probably to all alpha-emitting materials of appropriate half-life. Results with controlled air-flow through filters in series are consistent with the picture of small particles dislodged from the ''massive'' surface of an alpha-active material, and then repeatedly dislodged from positions on the filter fibers, by the alpha recoils. The process shows only a small dependence on the physical form of the source material. Oxide dust, nitrate salt, and plated metal all seem to generate the recoil particles effectively. The amount penetrating a series of filters depends on the total amount of activity in the source material, its specific activity, and the length of time of air flow. Dependence on the air flow velocity is slight. It appears that this phenomenon has not been observed in previous experiments with alpha-active aerosols because the tests did not continue for a sufficiently long time. A theoretical model of the process has been developed, amenable to computer handling, that should allow calculation of the rate constants associated with the transfer through and release of radioactive material from a filter system by this process

Recoil effect on β-decaying in vivo generators, interpreted for 103Pd/103mRh

International Nuclear Information System (INIS)

Szucs, Zoltan; Rooyen, Johann van; Zeevaart, Jan Rijn

2009-01-01

The use of Auger emitters as potential radiopharmaceuticals is being increasingly investigated. One of the radionuclides of interest is 103m Rh, which can be produced from 103 Ru or 103 Pd in an in vivo generator. A potential problem, however, is the recoil of the 103m Rh out of the carrier molecule and even out of the target cell. In order to determine the likelihood of this happening in the 103 Pd/ 103m Rh, case calculations were made to prove that this does not happen. The equations were generalised for all radionuclides with an atomic mass of 10-240 as a tool for determining the recoil threshold of any β-emitting radionuclide.

Microbeam recoil detection for hydration of minerals studies

Energy Technology Data Exchange (ETDEWEB)

Sie, S.H.; Suter, G.F. [CSIRO, North Ryde, NSW (Australia). Exploration and Mining Div.; Chekhmir, A.; Green, T.H. [Macquarie Univ., North Ryde, NSW (Australia)

1993-12-31

The glancing angle geometry is chosen to enable application of the elastic recoil detection microanalysis on thick geological samples, for hydrogen content determination. Simultaneous PIXE measurements can be used to eliminate the problem of uncertainties in beam charge collection. The method is applied to determine the hydration characteristics of silicates, produced experimentally at high pressure and temperature simulating the lower crust and upper mantle conditions. Preliminary results show that the technique can be applied readily on a microscopic (<100 {mu}m) scale for determination of H at fraction of atomic percent level. 9 refs., 3 figs.

Microbeam recoil detection for hydration of minerals studies

Energy Technology Data Exchange (ETDEWEB)

Sie, S H; Suter, G F [CSIRO, North Ryde, NSW (Australia). Exploration and Mining Div.; Chekhmir, A; Green, T H [Macquarie Univ., North Ryde, NSW (Australia)

1994-12-31

The glancing angle geometry is chosen to enable application of the elastic recoil detection microanalysis on thick geological samples, for hydrogen content determination. Simultaneous PIXE measurements can be used to eliminate the problem of uncertainties in beam charge collection. The method is applied to determine the hydration characteristics of silicates, produced experimentally at high pressure and temperature simulating the lower crust and upper mantle conditions. Preliminary results show that the technique can be applied readily on a microscopic (<100 {mu}m) scale for determination of H at fraction of atomic percent level. 9 refs., 3 figs.

Precision lifetime measurements using the recoil distance method

International Nuclear Information System (INIS)

Kruecken, R.

2000-01-01

The recoil distance method (RDM) for the measurements of lifetimes of excited nuclear levels in the range from about 1 ps to 1,000 ps is reviewed. The New Yale Plunger Device for RDM experiments is introduced and the Differential Decay Curve Method for their analysis is reviewed. Results from recent RDM experiments on SD bands in the mass-190 region, shears bands in the neutron deficient lead isotopes, and ground state bands in the mass-130 region are presented. Perspectives for the use of RDM measurements in the study of neutron-rich nuclei are discussed

Precision Lifetime Measurements Using the Recoil Distance Method

Science.gov (United States)

Krücken, R.

2000-01-01

The recoil distance method (RDM) for the measurements of lifetimes of excited nuclear levels in the range from about 1 ps to 1000 ps is reviewed. The New Yale Plunger Device for RDM experiments is introduced and the Differential Decay Curve Method for their analysis is reviewed. Results from recent RDM experiments on SD bands in the mass-190 region, shears bands in the neutron deficient lead isotopes, and ground state bands in the mass-130 region are presented. Perspectives for the use of RDM measurements in the study of neutron-rich nuclei are discussed. PMID:27551587

Recoil generated radiotracers in studies of molecular dynamics

International Nuclear Information System (INIS)

Spicer, L.D.

1981-01-01

This chapter summarizes many of the contributions that the recoil technique of generating excited radiotracer atoms in the presence of a thermal environment is making to the field of chemical dynamics. Specific topics discussed critically include characterization of the generation and behavior of excited molecules including fragmentation kinetics and energy transfer, measurement of thermal and hot kinetic parameters, and studies of reaction mechanisms and stereochemistry as a function of reaction energy. Distinctive features that provide unique approaches to dynamical problems are evaluated in detail and the complementarity with more conventional techniques is addressed. Prospects for future applications are also presented

Production and measurement of dispersion aerosols; application to the transport of deuteron-induced and 84Kr-induced reaction recoils

International Nuclear Information System (INIS)

Schmidt-Ott, W.-D.; Dincklage, R.-D. von

1977-01-01

Dispersion aerosols were produced from various fluids and mixed with helium, nitrogen, and air. The diameter of the aerosols was estimated from their deflection in a low density micro-jet. These two-phase flows were tested for their transport performance for recoils of deuteron-induced reactions at the Goettingen cyclotron. Transport yields of 70%, 90% and 86% were measured when using n-decane with helium, nitrogen, and air, respectively. In comparison to the earlier use of ethylene the amount of disturbing activity induced on the gases was much smaller. The effect of aerosol formation by condensation is discussed. The system was applied in electron- and γ-ray spectroscopy of deuteron-induced reaction recoils. The mixture of n-decane and helium was used for the transport of 84 Kr-induced reaction recoils at the Darmstadt UNILAC. (Auth.)

Effects of recoil-implanted oxygen on depth profiles of defects and annealing processes in P{sup +}-implanted Si studied using monoenergetic positron beams

Energy Technology Data Exchange (ETDEWEB)

Uedono, Akira; Moriya, Tsuyoshi; Tanigawa, Shoichiro [Tsukuba Univ., Ibaraki (Japan). Inst. of Materials Science; Kitano, Tomohisa; Watanabe, Masahito; Kawano, Takao; Suzuki, Ryoichi; Ohdaira, Toshiyuki; Mikado, Tomohisa

1996-04-01

Effects of oxygen atoms recoiled from SiO{sub 2} films on depth profiles of defects and annealing processes in P{sup +}-implanted Si were studied using monoenergetic positron beams. For an epitaxial Si specimen, the depth profile of defects was found to be shifted toward the surface by recoil implantation of oxygen atoms. This was attributed to the formation of vacancy-oxygen complexes and a resultant decrease in the diffusion length of vacancy-type defects. The recoiled oxygen atoms stabilized amorphous regions introduced by P{sup +}-implantation, and the annealing of these regions was observed after rapid thermal annealing (RTA) at 700degC. For a Czochralski-grown Si specimen fabricated by through-oxide implantation, the recoiled oxygen atoms introduced interstitial-type defects upon RTA below the SiO{sub 2}/Si interface, and such defects were dissociated by annealing at 1000degC. (author)

Charge-state related effects in sputtering of LiF by swift heavy ions

Energy Technology Data Exchange (ETDEWEB)

Assmann, W. [Ludwig-Maximilians-Universität München, 85748 Garching (Germany); Ban-d' Etat, B. [Centre de Recherche sur les Ions, les Matériaux et la photonique, CIMAP-GANIL, CEA–CNRS–ENSICAEN–Univ. Caen, 14070 Caen (France); Bender, M. [GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt (Germany); Boduch, P. [Centre de Recherche sur les Ions, les Matériaux et la photonique, CIMAP-GANIL, CEA–CNRS–ENSICAEN–Univ. Caen, 14070 Caen (France); Grande, P.L. [Univ. Fed. Rio Grande do Sul, BR-91501970 Porto Alegre, RS (Brazil); Lebius, H.; Lelièvre, D. [Centre de Recherche sur les Ions, les Matériaux et la photonique, CIMAP-GANIL, CEA–CNRS–ENSICAEN–Univ. Caen, 14070 Caen (France); Marmitt, G.G. [Univ. Fed. Rio Grande do Sul, BR-91501970 Porto Alegre, RS (Brazil); Rothard, H. [Centre de Recherche sur les Ions, les Matériaux et la photonique, CIMAP-GANIL, CEA–CNRS–ENSICAEN–Univ. Caen, 14070 Caen (France); Seidl, T.; Severin, D.; Voss, K.-O. [GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt (Germany); Toulemonde, M., E-mail: toulemonde@ganil.fr [Centre de Recherche sur les Ions, les Matériaux et la photonique, CIMAP-GANIL, CEA–CNRS–ENSICAEN–Univ. Caen, 14070 Caen (France); Trautmann, C. [GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt (Germany); Technische Universität Darmstadt, 64289 Darmstadt (Germany)

2017-02-01

Sputtering experiments with swift heavy ions in the electronic energy loss regime were performed by using the catcher technique in combination with elastic recoil detection analysis. The angular distribution of particles sputtered from the surface of LiF single crystals is composed of a jet-like peak superimposed on a broad isotropic distribution. By using incident ions of fixed energy but different charges states, the influence of the electronic energy loss on both components is probed. We find indications that isotropic sputtering originates from near-surface layers, whereas the jet component may be affected by contributions from depth up to about 150 nm.

Determination of the extraction efficiency for {sup 233}U source α-recoil ions from the MLL buffer-gas stopping cell

Energy Technology Data Exchange (ETDEWEB)

Wense, Lars v.d.; Seiferle, Benedict; Thirolf, Peter G. [Ludwig-Maximilians-Universitaet Muenchen, Garching (Germany); Laatiaoui, Mustapha [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Helmholtz Institut Mainz, Mainz (Germany)

2015-03-01

Following the α decay of {sup 233}U, {sup 229}Th recoil ions are shown to be extracted in a significant amount from the MLL buffer-gas stopping cell. The produced recoil ions and subsequent daughter nuclei are mass purified with the help of a customized quadrupole mass spectrometer. The combined extraction and mass purification efficiency for {sup 229}Th{sup 3+} is determined via MCP-based measurements and via the direct detection of the {sup 229}Th α decay. A large value of (10±2)% for the combined extraction and mass purification efficiency of {sup 229}Th{sup 3+} is obtained at a mass resolution of about 1u/e. In addition to {sup 229}Th, also other α-recoil ions of the {sup 233,} {sup 232}U decay chains are addressed. (orig.)

Processes to Open the Container and the Sample Catcher of the Hayabusa Returned Capsule in the Planetary Material Sample Curation Facility of JAXA

Science.gov (United States)

Fujimura, A.; Abe, M.; Yada, T.; Nakamura, T.; Noguchi, T.; Okazaki, R.; Ishibashi, Y.; Shirai, K.; Okada, T.; Yano, H.;

Experiments with a magnetic separator for heavy recoil ions

International Nuclear Information System (INIS)

Mosler, E.

1981-01-01

Using a triple-focusing (position and momentum), crescent-shaped separator for heavy recoil-ions different experiments were performed. The improvement consists in the enhancement of the transmission from 8% to 25% for 500 keV recoil ions from the reaction 238 U(α, 3n)sup(239m)Pu. For sup(237m)Pu the electromagnetic decay of the 1.1 μs shape isomer into the 82 ns shape isomer was searched for. The upper limit for gamma decay is 1.25 +- 1.25% for Esub(γ) = 200 keV and for electron decay 0.29 +- 0.29% in comparison to isomeric fission. The upper limit for interband transitions is 2.5% (2 delta), from which the upper limit of the partial half-life for the electromagnetic decay of the 1.1 μs isomer is calculated to 44 μs. Due to the performed interpretation the spin difference between both isomers extends at least to ΔI = 3. For sup(238m)U the back-decay into the 1. minimum by the EO-transition and the converted 2 + → 0 + transition in the first decay and the decay by alpha articles was looked for both in single measurements as in a coincidence measurement to L-X-ray quanta. The upper limits are GAMMAsub(EO) = 2.0, GAMMAsub(α)/GAMMAsub(F) = 0.4 and GAMMA(back-decay)/GAMMAsub(F) approx. equal to 100. (orig./HSI) [de

Velocity dependence of enhanced dynamic hyperfine field for Pd ions swiftly recoiling in magnetized Fe

International Nuclear Information System (INIS)

Stuchbery, A.E.; Ryan, G.C.; Bolotin, H.H.; Sie, S.H.

1980-01-01

The velocity-dependence of the magnitude of the enchanced dynamic hyperfine magnetic field (EDF) manifest at nuclei of 108 Pd ions swiftly recoiling through thin magnetized Fe has been investigated at ion velocities higher than have heretofore been examined for the heavier nuclides (i.e., at initial recoil velocities (v/Zv 0 )=0.090 and 0.160, v 0 =c/137). These results for 108 Pd, when taken in conjunction with those of prior similar measurements for 106 Pd at lower velocities, and fitted to a velocity dependence for the EDF, give for the Pd isotopes over the extended velocity range 1.74 0 )<=7.02, p=0.41+-0.15; a result incompatible with previous attributions of a linear velocity dependence for the field

Recent results from the chemistry of recoiling carbon and silicon atoms: The interplay between hot atom chemistry and gas kinetics

International Nuclear Information System (INIS)

Gaspar, P.P.; Garmestani, K.; Ferrieri, R.A.; Wolf, A.P.

1990-01-01

Recent results from the chemistry of recoiling carbon and silicon atoms illustrate the power of an experimental approach to the solution of complex mechanistic problems that combines the study of the reactions of recoiling atoms with conventional gas kinetic techniques. Included will be the reactions of 11 C atoms with anisole, addressing the question whether an aromatic pi-electron system can compete as a reactive site with carbon-hydrogen bonds

A systematic study of actinide production from the interactions of heavy ions with sup 248 Cm

Energy Technology Data Exchange (ETDEWEB)

Leyba, J.D.

1990-09-07

Production cross sections for heavy actinides produced from the interactions of {sup 12}C, {sup 31}P, {sup 40}Ar, and {sup 44}Ca ions with {sup 248}Cm were measured at energies ranging from 0.98 to 1.35 X Coulomb barrier. The recoiling reaction products were collected in copper or gold catcher foils located near the {sup 248}Cm target. Separate fractions of Bk, Cf, Es, Fm, and Md were obtained from a radiochemical separation procedure. For the {sup 12}C system, a He/KCl jet was used to transport the recoiling No activities of interest to a rotating wheel system. The isotopic distributions of the actinide products were found to be essentially symmetric about the maximum with full-widths-at-half-maximum of approximately 2.5 mass units. Isotopic distributions of the {sup 12}C, {sup 31}P, {sup 40}Ar, and {sup 44}Ca systems were found to be very similar to the {sup 40,48}Ca systems studied previously. The maxima of the isotopic distributions generally occurred for those reaction channels which involved the exchange of the fewest number of nucleons between the target and projectile for which the calculated excitation energy was a positive quantity. Additionally, the maxima of the excitation functions occurred at those projectile energies which were consistent with the calculated reaction barriers based upon a binary reaction mechanism. The experimental data from the four systems investigated were compared to several models of heavy ion interactions including a damped reaction mechanism, compound nucleus formation and subsequent particle evaporation, and classical partial wave calculations for binary systems.

Effect of γ-exposure on retention of recoil 56Mn in permanganates

International Nuclear Information System (INIS)

Mishra, S.P.; Vijaya

2002-01-01

Full text: γ-exposure effect on recombination of recoil 56 Mn atom in La, Sr and Ba permanganates were studied with a special emphasis to pre-and post-activation γ-ray irradiation treatment using 60 Co source. Permanganates were inactivated by ionizing radiation as a function of γ-dose without neutron irradiation, however, pronounced effects were seen after neutron activation. Pre-irradiation increase the initial retention and promotes the annealing phenomenon as the introduction of defect into the lattice though on the other hand radiolytic phenomenon may also appear. Pre-activated sample gave higher retention value for lanthanum and barium permanganates in comparison to strontium permanganate at different γ-doses for desired period of gamma annealing than those obtained at corresponding γ-doses for similar length of time in case of post-activated targets. Kinetics of annealing by γ-radiolytic effects follow first order rate law. The observed results are discussed in the light of existing ideas for understanding the recoil stabilization phenomenon of parent reformation and the nature of precursors in permanganates

Commissioning of the recoil silicon detector for the HERMES experiment

International Nuclear Information System (INIS)

Pickert, N.C.

2008-02-01

The reconstruction of the missing mass is limited by the position and momentum resolution of the HERMES spectrometer. In order to reach a higher accuracy in the measurements the backscattered nucleon must also be detected. A detector suited for this must give the possibility, to determine the momentum of the particles over a very large range: from minimally ionizing particles up to protons, which are stopped in the detector. The detector must also be able to discriminate hadrons and mesons as well as cover the complete spatial region around the target. In the winter 2005-2006 such a recoil detector was installed in the HERMES experiment. The detector sonsists of three partial detectors, a silicon counter within the scattering chamber, a sintillating-fiber detector and a photon detector. Before the installation of the detector the silicon modules were tested in a bench test and checked together with the other particle detectors in a test experiment. A large part of this dissertation is dedicated to the planning and performance of these tests as well to the evaluation of them. It could be show, that the modules worked accordly to their specifications, however because of unexpectedly high noise a signal correction became necessary. Different models for the correction were developed and tested in the framework of these thesis. In spite of the high noise cosmic muons could be detected and their energy deposition measured with a signal-to-noise ratio of 2:1. In the winter break 2005-2006 the recoil detector was installed into the HERMES experiment. First diagnosis and analysis software was developed. The silicon detector measured successfully energy depositions of minimally ionizing particles up to protons stopped in the sensor. Minimally ionizing particles could be detected with a signal-to-noise ratio of 5:1. By means of track information of the scintillating-fiber detector protons could be discriminated from pions and other mesons by the silicon detector. The HERMES

Commissioning of the recoil silicon detector for the HERMES experiment

Energy Technology Data Exchange (ETDEWEB)

Pickert, N C

2008-02-15

The reconstruction of the missing mass is limited by the position and momentum resolution of the HERMES spectrometer. In order to reach a higher accuracy in the measurements the backscattered nucleon must also be detected. A detector suited for this must give the possibility, to determine the momentum of the particles over a very large range: from minimally ionizing particles up to protons, which are stopped in the detector. The detector must also be able to discriminate hadrons and mesons as well as cover the complete spatial region around the target. In the winter 2005-2006 such a recoil detector was installed in the HERMES experiment. The detector sonsists of three partial detectors, a silicon counter within the scattering chamber, a sintillating-fiber detector and a photon detector. Before the installation of the detector the silicon modules were tested in a bench test and checked together with the other particle detectors in a test experiment. A large part of this dissertation is dedicated to the planning and performance of these tests as well to the evaluation of them. It could be show, that the modules worked accordly to their specifications, however because of unexpectedly high noise a signal correction became necessary. Different models for the correction were developed and tested in the framework of these thesis. In spite of the high noise cosmic muons could be detected and their energy deposition measured with a signal-to-noise ratio of 2:1. In the winter break 2005-2006 the recoil detector was installed into the HERMES experiment. First diagnosis and analysis software was developed. The silicon detector measured successfully energy depositions of minimally ionizing particles up to protons stopped in the sensor. Minimally ionizing particles could be detected with a signal-to-noise ratio of 5:1. By means of track information of the scintillating-fiber detector protons could be discriminated from pions and other mesons by the silicon detector. The HERMES

Mass and energy dispersive recoil spectrometry of GaAs structures

International Nuclear Information System (INIS)

Hult, M.

1994-01-01

Mass and energy dispersive Recoil Spectrometry (RS) using heavy ions at energies of about 0.2Α-0.8Α MeV has attracted much interest recently due to its potential for separately and unambiguously generating information on isotopic depth distributions. The principal advantages of mass and energy dispersive RS are that both light and heavy elements can be separately studied simultaneously and problems caused by chemical matrix effects are avoided since the technique is based on high energy nucleus-nucleus scattering. In order to elucidate reactions taking place in various GaAs structures, Time of flight-Energy (ToF-E) RS was developed to allow Ga and As to be studied separately down to depths of about 500-800 nm with a depth resolution of about 16 nm at the surface. This was shown in a study of an Al x Ga 1-x As quantum-well structure. The benefits of using ToF-E RS on GaAs structures were further demonstrated in studies of Co/GaAs and CoSi 2 /GaAs reactions, as well as in a study of the composition of MOCVD grown Al x Ga 1-x As. Most recoil measurements employed 127 I at energies of about 50-90 MeV as projectiles. The recoil detector telescope consisted of a silicon energy detector and two carbon foil time pick-off detectors separated by a variable flight length of 213.5-961 mm. The reactions taking place between various thin films and GaAs were also studied using complementary techniques such as XRD, XPS and SEM. Co was found to react extensively with GaAs, already at about 300 degrees C, making it unsuitable as a contact material. Thin films of Co and Si were found to react extensively with each other and to form CoSi 2 at 500 degrees C and above. CoSi 2 , a low resistivity silicide, turned out to be stable on GaAs, at least up to 700 degrees C. Considerable grain growth could cause problems, however, in the use of CoSi 2 -contacts. 112 refs, figs, tabs

Proton-recoil proportional counter tests at TREAT

International Nuclear Information System (INIS)

Fink, C.L.; Eichholz, J.J.; Burrows, D.R.; DeVolpi, A.

1979-01-01

A methane filled proton-recoil proportional counter will be used as a fission neutron detector in the fast-neutron hodoscope. To provide meaningful fuel-motion information the proportional counter should have: a linear response over a wide range of reactor powers background ratio (the number of high energy neutrons detected must be maximized relative to low energy neutrons, and gamma ray sensitivity must be kept small); and a detector efficiency for fission neutrons above 1 MeV of approximately 1%. In addition, it is desirable that the detector and the associated amplifier/discriminator be capable of operating at counting rates in excess of 500 kHz. This paper reports on tests that were conducted on several proportional counters at the TREAT reactor

Three-dimensional recoil-ion momentum analyses in 8.7 MeV O7+-He collisions

International Nuclear Information System (INIS)

Kambara, T.; Tang, J.Z.; Awaya, Y.

1995-01-01

Using high-resolution recoil-ion momentum spectroscopy we have measured the differential cross sections of single-electron capture and target single-ionization processes for 8.7 MeV O 7+ -He collisions as functions of scattering angle. A transverse momentum resolution of ±0.2 au, which corresponds to an angular resolution of about ±1.5x10 -6 rad for the projectile scattering angle, was obtained by intersecting a well collimated O 7+ beam with a target of a supersonic He jet from a pre-cooled gas and by measuring the recoil-ion transverse momentum. For the single capture reaction, information on the n-value of the electron final state in O 6+ (1snl) is obtained from the longitudinal momentum of the recoil ions. In pure single-electron capture, the dominant contributions to capture were found to be those from the n=4 and higher states, whereas single capture accompanied by the ionization of the second target electron mainly populates n=2 to n=4 states. Furthermore, the measured transverse momentum distribution differs significantly between pure single capture and capture with simultaneous ionization. The measured data for the pure capture process compare favourably with theoretical results based on a molecular-state expansion method. Other experimental data are discussed in terms of the classical overbarrier model. (author)

Evaluation of hip internal and external rotation range of motion as an injury risk factor for hip, abdominal and groin injuries in professional baseball players

Directory of Open Access Journals (Sweden)

Xinning Li

2015-12-01

Full Text Available Normal hip range of motion (ROM is essential in running and transfer of energy from lower to upper extremities during overhead throwing. Dysfunctional hip ROM may alter lower extremity kinematics and predispose athletes to hip and groin injuries. The purpose of this study is characterize hip internal/external ROM (Arc and its effect on the risk of hip, hamstring, and groin injuries in professional baseball players. Bilateral hip internal and external ROM was measured on all baseball players (N=201 in one professional organization (major and minor league during spring training. Players were organized according to their respective positions. All injuries were documented prospectively for an entire MLB season (2010 to 2011. Data was analyzed according to position and injuries during the season. Total number of players (N=201 with an average age of 24±3.6 (range=17-37. Both pitchers (N=93 and catchers (N=22 had significantly decreased mean hip internal rotation and overall hip arc of motion compared to the positional players (N=86. Players with hip, groin, and hamstring injury also had decreased hip rotation arc when compared to the normal group. Overall, there is a correlation between decreased hip internal rotation and total arc of motion with hip, hamstring, and groin injuries.

Use of the on-line Moessbauer effect as a contribution to the study of recoil defects in solids

International Nuclear Information System (INIS)

Jeandey, Christian

1974-01-01

This research thesis addresses the study of effects of nuclear reactions, also known as 'after-effects' such as atomic disorders resulted from atom recoil, but also possible chemical modifications. The author more particularly focuses of recoil defects. He reports a critical review of studies of structure defects (in pure metals, ordered alloys, ionic crystals) performed by using conventional resonance absorption, and then presents an analysis of results of the defect creation dynamics as it had been proposed by other authors. He also proposes an overview of the evolution and disappearance of defects during thermal treatments. After a review of experiments based on the on-line Moessbauer effect, the author reports the study of recoil effects in pure metals (iron, hafnium), in alloys (Fe 1-x Al x , FeGe 2 , cubic, monoclinic and hexagonal FeGe), and in organic complexes (ferrous oxalate, different types of hafnium chelate, hafnium oxide). He finally discusses the electronic properties of different types of iron and hafnium chelate in solid phase [fr

Recoil properties of radionuclides formed in photospallation reactions on complex nuclei at intermediate energies

International Nuclear Information System (INIS)

Haba, Hiromitsu; Oura, Yasuji; Shibata, Seiichi; Furukawa, Michiaki; Fujiwara, Ichiro

2001-01-01

A short review is given on our studies of recoil properties of radionuclides formed in photospallation reactions induced by bremsstrahlung of end-point energies (E 0 ) from 600 to 1100 MeV, in which the thick-target thick-catcher method was employed. The measurements have been successful on 14, 24, 26, 31, 21 and 20 nuclides from nat V, nat Cu, 93 Nb, nat Ag, nat Ta, and 197 Au, respectively. Reflecting the resonance character in a photonuclear reaction, the mean ranges FW and BW in the forward and backward directions, respectively, are E 0 -independent at the studied energies and classified into two groups accounting for the (γ, xn) (x ≥ 1) and (γ, xnyp) (x, y ≥ 1) processes. The forward-to-backward ratios (F/B) are independent of the mass difference (ΔA) between a product (A p ) and a target (A t ) and also of A t . The kinematic properties of the product nuclei were analyzed by the two-step vector velocity model. The forward velocity ν after the first step of photon-reaction is quite different from that of proton-reaction at proton energies of E p ≤ 3 GeV, though the difference disappears at higher energies. On the other hand, the mean kinetic energy T of the residual nucleus in the second step is almost equal to that of proton-reaction irrespective of E p . A comparison with T values calculated by the PICA (Photon-Induced Intranuclear Cascade Analysis) code at E 0 =400 MeV was also performed. It was found that although the code well reproduces the experimental results of nat V and nat Cu, the same calculation for heavier targets gives T values lower than the experimental results, indicating some nuclear-structure effect, such as a medium effect notably at A t ≥ 100. An average kinetic energy carried off by the emitted particles ε s =T/(ΔA/A t ) of both photon- and proton-reactions seem to increase with an increase of A t up to around A t =100, and become almost constant at larger A t , implying some change in the nuclear structure effect in this

Status and outlook of the FRS ion catcher at GSI

Energy Technology Data Exchange (ETDEWEB)

Ebert, Jens [Justus-Liebig-Universitaet Giessen (Germany)

2016-07-01

Exotic nuclei are produced in stellar processes like the p- and r-process and are essential for our understanding of nucleosynthesis beyond iron. They have an unusual ratio of neutrons to protons and short half-lives in common. Important production methods for exotic nuclei in the laboratory are projectile fragmentation and fission of heavy ions. Nuclei produced this way have energies up to several GeV/u and must be slowed down and separated from other beam products and contaminants for high-accuracy low-energy experiments with traps and lasers. This is tested by the FRS Ion Catcher, which is a test bench for the low energy branch of the Super-FRS at FAIR. There, the nuclei are separated in-flight, range-bunched, slowed-down in the fragment separator and subsequently thermalized in a cryogenic stopping cell. The ions extracted from the stopping cell will be transported to a multiple-reflection time-of-flight mass spectrometer for high accuracy mass measurements, decay spectroscopy or separation and preparation for further experiments. A novel technical method allows mass measurements of nuclides with half-lifes of about 1ms such as {sup 215}Po. From our online campaign in 2014 almost background-free α-spectroscopy, mass selected decay spectroscopy and measurements of excitation energies and isomeric ratios are presented together with instrumental advances.

Probing the structure of unstable nuclei through the recoiled proton tagged knockout reaction

International Nuclear Information System (INIS)

Ye, Y.; Cao, Z.; Jiang, D.

2010-01-01

Recoiled proton tagged knockout reaction experiments were carried-out for 8 He at 82,5 MeV/u in RIKEN and for 6 He at 65 MeV/u in Lanzhou. The very preliminary results for the distinguish of the reaction mechanism are presented and compared to the kinematics calculation. (authors)

Irradiation of Methane by Recoiling Fission-Fragments

Energy Technology Data Exchange (ETDEWEB)

Hall, G. R.; Galley, M. R. [Imperial College of Science and Technology, London (United Kingdom)

1963-11-15

Pure methane gas (containing <0.003% oxygen and <5 mg H{sub 2}O per m{sup 3}) has been irradiated at pressures ranging from 5 to 50 atmospheres pressure and at 30{sup o}C with recoiling fission - fragments. The gas is contained in a silica ampoule of volume about 9 cm{sup 3} and which also contains a platinum cylinder coated on the inside with 0.5 mg/cm{sup 2} highly enriched uranium oxide. When the ampoule is irradiated in a nuclear reactor with thermal neutrons, about half the fission-fragments recoil from the uranium and dissipate their energy in the methane. In a typical irradiation, methane at 10 atm pressure receives a dose of 5 x 10{sup 21} eV at an integrated reactor flux of 5 x 10{sup 15} neutrons/cm{sup 2}. Neutron flux i s measured by means of a gold-foil flux monitor. The activity of the Au{sup 198} is counted in a 4 {pi} proportional counter. The irradiation products have been detected by using beta-ionization detectors for gas-phase chromatography with suitable columns. The following products have been found: hydrogen, ethane, propane, n-butane, isobutane, n-pentane, iso-pentane, neo-pentane, the seven hexanes. Traces of higher hydrocarbons are undoubtedly present but the analysis of these has not been attempted. Hydrogen is present in greatest yield and the yields of the hydrocarbons decrease in the order given above. Despite previously reported yields of ethylene (G-value-0.1) from gamma and fast - electron irradiations, no ethylene or other unsaturated products have been detected in this work. It would have been possible to detect 10 ppm in the products. This is to be expected as any double bonds which may be produced would almost immediately be hydrogenated by the hydrogen present. Yields for hydrogen, ethane and propane lie within the range of values that have been reported by other workers for gamma and fast electron irradiations. (author)

Sub-recoil cooling up to nano-Kelvin. Direct measurement of spatial coherency length. New tests for Levy statistics

International Nuclear Information System (INIS)

Saubamea, B.

1998-12-01

This thesis presents a new method to measure the temperature of ultracold atoms from the spatial autocorrelation function of the atomic wave-packets. We thus determine the temperature of metastable helium-4 atoms cooled by velocity selective dark resonance, a method known to cool the atoms below the temperature related to the emission or the absorption of a single photon by an atom at rest, namely the recoil temperature. This cooling mechanism prepares each atom in a coherent superposition of two wave-packets with opposite mean momenta, which are initially superimposed and then drift apart. By measuring the temporal decay of their overlap, we have access to the Fourier transform of the momentum distribution of the atoms. Using this method, we can measure temperatures as low as 5 nK, 800 times as small as the recoil temperature. Moreover we study in detail the exact shape of the momentum distribution and compare the experimental results with two different theoretical approaches: a quantum Monte Carlo simulation and an analytical model based on Levy statistics. We compare the calculated line shape with the one deduced from simulations, and each theoretical model with experimental data. A very good agreement is found with each approach. We thus demonstrate the validity of the statistical model of sub-recoil cooling and give the first experimental evidence of some of its characteristics: the absence of steady-state, the self-similarity and the non Lorentzian shape of the momentum distribution of the cooled atoms. All these aspects are related to the non ergodicity of sub-recoil cooling. (author)

Pulse-shape discrimination between electron and nuclear recoils in a NaI(Tl) crystal

International Nuclear Information System (INIS)

Lee, H.S.; Adhikari, G.; Adhikari, P.; Choi, S.; Hahn, I.S.

2015-01-01

We report on the response of a high light-output NaI(Tl) crystal to nuclear recoils induced by neutrons from an Am-Be source and compare the results with the response to electron recoils produced by Compton-scattered 662 keV γ-rays from a 137 Cs source. The measured pulse-shape discrimination (PSD) power of the NaI(Tl) crystal is found to be significantly improved because of the high light output of the NaI(Tl) detector. We quantify the PSD power with a quality factor and estimate the sensitivity to the interaction rate for weakly interacting massive particles (WIMPs) with nucleons, and the result is compared with the annual modulation amplitude observed by the DAMA/LIBRA experiment. The sensitivity to spin-independent WIMP-nucleon interactions based on 100 kg⋅year of data from NaI detectors is estimated with simulated experiments, using the standard halo model.

Pulse-shape discrimination between electron and nuclear recoils in a NaI(Tl) crystal

Energy Technology Data Exchange (ETDEWEB)

Lee, H.S. [Department of Physics, Ewha Womans University,Seoul 120-750 (Korea, Republic of); Adhikari, G.; Adhikari, P. [Department of Physics, Sejong University,Seoul 143-747 (Korea, Republic of); Choi, S. [Department of Physics and Astronomy, Seoul National University,Seoul 151-747 (Korea, Republic of); Hahn, I.S. [Department of Science Education, Ewha Womans University,Seoul 120-750 (Korea, Republic of)

2015-08-18

We report on the response of a high light-output NaI(Tl) crystal to nuclear recoils induced by neutrons from an Am-Be source and compare the results with the response to electron recoils produced by Compton-scattered 662 keV γ-rays from a {sup 137}Cs source. The measured pulse-shape discrimination (PSD) power of the NaI(Tl) crystal is found to be significantly improved because of the high light output of the NaI(Tl) detector. We quantify the PSD power with a quality factor and estimate the sensitivity to the interaction rate for weakly interacting massive particles (WIMPs) with nucleons, and the result is compared with the annual modulation amplitude observed by the DAMA/LIBRA experiment. The sensitivity to spin-independent WIMP-nucleon interactions based on 100 kg⋅year of data from NaI detectors is estimated with simulated experiments, using the standard halo model.

Design and preliminary analysis of in-vessel core catcher made of high-temperature ceramics material in PWR

International Nuclear Information System (INIS)

Xu Hong; Ma Li; Wang Junrong; Zhou Zhiwei

2011-01-01

In order to protect the interior wall of pressure vessel from melting, as an additional way to external reactor vessel cooling (ERVC), a kind of in-vessel core catcher (IVCC) made of high-temperature ceramics material was designed. Through the high-temperature and thermal-resistance characteristic of IVCC, the distributing of heat flux was optimized. The results show that the downward average heat flux from melt in ceramic layer reduces obviously and the interior wall of pressure vessel doesn't melt, keeping its integrity perfectly. Increasing of upward heat flux from metallic layer makes the upper plenum structure's temperature ascend, but the temperature doesn't exceed its melting point. In conclusion, the results indicate the potential feasibility of IVCC made of high-temperature ceramics material. (authors)

Automatic detection of recoil-proton tracks and background rejection criteria in liquid scintillator-micro-capillary-array fast neutron spectrometer

Science.gov (United States)

Mor, Ilan; Vartsky, David; Dangendorf, Volker; Tittelmeier, Kai.; Weierganz, Mathias; Goldberg, Mark Benjamin; Bar, Doron; Brandis, Michal

2018-06-01

We describe an analysis procedure for automatic unambiguous detection of fast-neutron-induced recoil proton tracks in a micro-capillary array filled with organic liquid scintillator. The detector is viewed by an intensified CCD camera. This imaging neutron detector possesses the capability to perform high position-resolution (few tens of μm), energy-dispersive transmission-imaging using ns-pulsed beams. However, when operated with CW or DC beams, it also features medium-quality spectroscopic capabilities for incident neutrons in the energy range 2-20 MeV. In addition to the recoil proton events which display a continuous extended track structure, the raw images exhibit complex ion-tracks from nuclear interactions of fast-neutrons in the scintillator, capillaries quartz-matrix and CCD. Moreover, as expected, one also observes a multitude of isolated scintillation spots of varying intensity (henceforth denoted "blobs") that originate from several different sources, such as: fragmented proton tracks, gamma-rays, heavy-ion reactions as well as events and noise that occur in the image-intensifier and CCD. In order to identify the continuous-track recoil proton events and distinguish them from all these background events, a rapid, computerized and automatic track-recognition-procedure was developed. Based on an appropriately weighted analysis of track parameters such as: length, width, area and overall light intensity, the method is capable of distinguishing a single continuous-track recoil proton from typically surrounding several thousands of background events that are found in each CCD frame.

Analysis of hard exclusive scattering processes of the HERMES recoil experiment

International Nuclear Information System (INIS)

Brodski, Irina

2014-11-01

Deeply virtual Compton Scattering (DVCS), ep → epγ is the simplest reaction giving indication of generalized parton distributions (GPD) of the nucleon. The DVCS process has the same final state as the Bethe-Heitler process (BH). For this reason the access is taken not through the cross-sections directly but through asymmetries between DVCS events depending on charge and polarization of the 27.6 GeV beam. For the first time the azimuthal asymmetry amplitudes according the charge of the lepton beam are extracted using a kinematically complete reconstruction method at the HERMES experiment. The recoil detector installed in 2006 allows the reconstruction of recoiling protons that completes the measurements of the forward detector to cover almost the complete angle range around the vertex. This approach allows suppressing the background processes by almost a complete magnitude compared to the traditional method using only the information of the forward spectrometer. The analysis of the asymmetries was carried out at different values of the kinematic variables t c' x B and Q 2 to investigate the dependence of these variables. This work pushes the limits of the readability of data and shows which periods have been found to be unstable in the data acquisition. It points out the impact of this finding to previous HERMES publications.

Chemical effects of /sup 32/P recoil atom

Energy Technology Data Exchange (ETDEWEB)

Matsuura, N [Tokyo Univ. (Japan). Coll. of General Education

1975-06-01

Szilard-Chalmers' effect of /sup 32/P were reviewed. The concentration method using Szilard-Chalmers' effect in production of radioisotope, circumstances such as exposure time in an atomic pile, states of target substances and the yields by them were discussed. Many kinds of chemical effects, such as chemical effects of /sup 32/P recoil atom in phosphorated glass, studies of the effect of adducts, the threshold of ..gamma..-ray effect, the oxidation number of /sup 32/P in phosphorated glass by exposure time in the pile and the labelling position of /sup 32/P, are associated with caryotransformation (nuclear transformation) by environmental factors. The abovementioned articles were explained concerning /sup 32/P.

CDMS Detector Fabrication Improvements and Low Energy Nuclear Recoil Measurements in Germanium

Energy Technology Data Exchange (ETDEWEB)

Jastram, Andrew [Texas A & M Univ., College Station, TX (United States)

2015-12-01

As the CDMS (Cryogenic Dark Matter Search) experiment is scaled up to tackle new dark matter parameter spaces (lower masses and cross-sections), detector production efficiency and repeatability becomes ever more important. A dedicated facility has been commissioned for SuperCDMS detector fabrication at Texas A&M University (TAMU). The fabrication process has been carefully tuned using this facility and its equipment. Production of successfully tested detectors has been demonstrated. Significant improvements in detector performance have been made using new fabrication methods, equipment, and tuning of process parameters. This work has demonstrated the capability for production of next generation CDMS SNOLAB detectors. Additionally, as the dark matter parameter space is probed further, careful calibrations of detector response to nuclear recoil interactions must be performed in order to extract useful information (in relation to dark matter particle characterzations) from experimental results. A neutron beam of tunable energy is used in conjunction with a commercial radiation detector to characterize ionization energy losses in germanium during nuclear recoil events. Data indicates agreement with values predicted by the Lindhard equation, providing a best-t k-value of 0.146.

A Stylistic Analysis of Four Translations of J. D. Salinger's The Catcher in the Rye

Directory of Open Access Journals (Sweden)

Silva Bratož

2004-12-01

Full Text Available The paper looks at stylistic differences between four translations of J. D. Salinger’s Catcher in the Rye – two Slovene translations, a Serbo-Croatian, and an Italian translation. Firstly, stylistic components relevant to the novel in question are identified. In this respect, the translation of teenage speech and idiom appears to be not only the most conspicuous stylistic feature of the original but also the hardest to translate. Secondly, the ways in which the different translations have rendered certain formal and lexical features of style are compared by determining and describing their function. A large number of examples have been submitted to critical scrutiny, of which only a few representative ones are listed and explained in the paper. Finally, this paper points to some particular difficulties of the four translators in their attempts to reproduce the stylistic components of the original.

Studies of rotational structures in the neutron-rich niobium isotopes 101-103

International Nuclear Information System (INIS)

Paffrath, U.

1989-08-01

The aim of this thesis was to study rotational structures in the low-lying levels of the niobium isotopes 101, 102, and 103. This was performed at the recoil separator JOSEF of the Nuclear Research Facility Juelich by studies of the β-decays of the zirconium isotopes 101-103 into their niobium daughters. By γ-γ respectively X-γ coincidence measurements the already existing term schemes of the niobium isotopes should be verified respectively extended and by γ-γ angular-correlation measurements the rotational structures should be studied. The term schemes of the niobium isotopes 101 and 102 could be confirmed in the framework of the performed experiments while the level scheme of the 103 Nb could be essentially extended. From the X-γ coincidence measurement for a plurality of γ transitions the conversion coefficients and by this the dominant multipolarities could be determined. With these conversion coefficients then also the mixing parameters were calculated. These data together with the results from the γ-γ angular-correlation experiments led to a fixing concerning the spins and parities at a series of levels in all three niobium isotopes. (orig./HSI) [de

Analytic calculation of radiative-recoil corrections to muonium hyperfine splitting: Electron-line contribution

International Nuclear Information System (INIS)

Eides, M.I.; Karshenboim, S.G.; Shelyuto, V.A.

1991-01-01

The detailed account of analytic calculation of radiative-recoil correction to muonium hyperfine splitting, induced by electron-line radiative insertions, is presented. The consideration is performed in the framework of the effective two-particle formalism. A good deal of attention is paid to the problem of the divergence cancellation and the selection of graphs, relevant to radiative-recoil corrections. The analysis is greatly facilitated by use of the Fried-Yennie gauge for radiative photons. The obtained set of graphs turns out to be gauge-invariant and actual calculations are performed in the Feynman gauge. The main technical tricks, with the help of which we have effectively utilized the existence in the problem of the small parameter-mass ratio and managed to perform all calculations in the analytic form are described. The main intermediate results, as well as the final answer, δE rr = (α(Ζα)/π 2 )(m/M)E F (6ζ(3) + 3π 2 In 2 + π 2 /2 + 17/8), are also presented

Commissioning and performance studies of a proton recoil detector at the COMPASS-II experiment

Energy Technology Data Exchange (ETDEWEB)

Joerg, Philipp; Buechele, Maximilian; Fischer, Horst; Gorzellik, Matthias; Grussenmeyer, Tobias; Herrmann, Florian; Koenigsmann, Kay; Kremser, Paul; Schopferer, Sebastian [Physikalisches Institut, Albert-Ludwigs-Universitaet Freiburg (Germany); Collaboration: COMPASS Collaboration

2014-07-01

The COMPASS-II experiment is a fixed target experiment situated at CERN. A tertiary myon beam from the SPS scattered of protons from a liquid hydrogen target is used to measure Deeply Virtual Compton Scattering (DVCS) and Hard Exclusive Meson Production (HEMP). These processes offer a unique way to determine Generalized Parton Distributions, which are related to the total angular momentum of quarks, antiquarks and gluons in the nucleon by Ji's Sum Rule. One of the major parts of the COMPASS-II upgrade is the CAMERA detector. CAMERA is a proton recoil detector surrounding the COMPASS-II liquid hydrogen target. Its purpose is to measure the recoiled target proton in DVCS and HEMP reactions and viz to act as a veto to ensure the exclusivity of the measurement. The talk gives an outline of the detector and its readout electronics. It is focused on the commissioning and performance of the CAMERA detector and gives a brief insight into the ongoing DVCS analysis.

Szilard-Chalmers cation recoil studies in zeolites X and Y. Pt. 3. Recoils from locked to open sites

Energy Technology Data Exchange (ETDEWEB)

Lai, P P; Rees, L V.C. [Imperial Coll. of Science and Technology, London (UK)

1976-01-01

The Szilard-Chalmers recoil of the cations Rb/sup +/, Cs/sup +/, Ba/sup 2 +/, La/sup 3 +/, Co/sup 2 +/, Zn/sup 2 +/, Cu/sup 2 +/ and Na/sup +/ from the sodalite cage and hexagonal prism sites into the supercage sites of zeolites X and Y has been studied. This study is complementary to that described in Lai et al, JCS Faraday I; 72:181 (1976). It has been found that these cations recoil from the sodalite cage sites into the supercage sites with a probability of approximately 90% whereas the corresponding probability for these cations in the hexagonal prism sites (site I) is between 40 and 50% depending on the cation. It is thus possible to determine the preferences shown by these cations for these 'locked-in' sites as a function of temperature of calcination, Tsub(c), concentration and type of other cations contained in these sites. In these studies the cations present in the supercage sites before irradiation were usually NH/sub 4//sup +/ but Ba/sup 2 +/, Ca/sup 2 +/ and Na/sup +/ have also been used. When Tsub(c) > 400/sup 0/C, Rb/sup +/ and Cs/sup +/ began to populate site I. These ions populated this site in zeolite X at lower calcination temperatures than required for zeolite Y. When Tsub(c) was increased from 110 to 220/sup 0/C the occupancy of site I by Ba/sup 2 +/ was greatly enhanced and when Tsub(c) > 440/sup 0/C Ba/sup 2 +/ ions now occupied this site in preference to all other 'locked-in' sites. Barium exhibited a higher affinity for site I in zeolite X than in zeolite Y when Tsub(c) = 110/sup 0/C. If dehydrated La-Y was assumed to have 5 La/sup 3 +/ ions per u.c. in site I, the hydration of this material did not change the concentration of La/sup 3 +/ in site I. Co/sup 2 +/, Zn/sup 2 +/ and Cu/sup 2 +/ ions all exhibited similar affinities for the 'locked-in' sites of zeolites X and Y.

Complete analytic results for radiative-recoil corrections to ground-state muonium hyperfine splitting

International Nuclear Information System (INIS)

Karshenboim, S.G.; Shelyuto, V.A.; Eides, M.E.

1988-01-01

Analytic expressions are obtained for radiative corrections to the hyperfine splitting related to the muon line. The corresponding contribution amounts to (Z 2 a) (Za) (m/M) (9/2 ζ(3) - 3π 2 ln 2 + 39/8) in units of the Fermi hyperfine splitting energy. A complete analytic result for all radiative-recoil corrections is also presented

Experimental analysis of ex-vessel core catcher cooling system performance for EU-APR1400 during severe accident

Energy Technology Data Exchange (ETDEWEB)

Song, K. W.; Park, H. S.; Revankar, S. T. [POSTECH, Pohang (Korea, Republic of); Kim, H. Y. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2016-10-15

In the coolant channel which has a unique design and large scale flow paths, natural circulation is passively activated by buoyancy driven force. Since two-phase flow behavior in a large scale channel is different from that in a small scale channel, the two-phase flow affecting the cooling capability is difficult to be predicted in the large channel. Therefore, cooling experiment in the core catcher coolant path is necessary. Cooling Experiment - Passive Ex-vessel corium retaining and Cooling System(CE-PECS) is constructed in full scale(in height and width) slice of half prototype. It actually simulates steam-water flow in the coolant channel for different decay heat condition of the corium. In this study, thermal power considering of total amount of decay heat 190 kW which corresponds to 40MW of thermal power in the prototype is loaded on the top wall of the CE-PECS coolant channel. Natural circulation flow rate and pressure drops at the two-phase region are measured in various power level. Temperatures of heater block and working fluid in various position along the flow path enable to calculate heat fluxes and heat transfer coefficients distribution. These results are used for evaluating heat removal capability of core catcher facility. Two-phase natural circulation experiment is carried out in CE-PECS facility. Based on the prototypic condition, 190 kW of total power is supplied to the top of the coolant path. Uniform distribution of heat load on the downward facing heater bock produces -300 kW/m2 at 100 % power ratio. Although the experiment should consider the heat loss and heat flux uniformity, several noticeable conclusions have been made as followings; 1. Mass flow rate and two-phase pressure drop are measured in various power conditions. 2. Slightly inclined top wall at the downstream of the channel shows better heat exchange performance than horizontal top wall because enhanced convection due to the increase of void fraction improves local cooling. This

The ANTARES recoil time-of-flight spectrometer

Energy Technology Data Exchange (ETDEWEB)

Martin, J.W.; Russell, G.J. [New South Wales Univ., Kensington, NSW (Australia); Cohen, D.D.; Dytlewski, N. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

1996-12-31

The Australian National Tandem for Applied Research (ANTARES), is a 8MV FN tandem particle accelerator at the Australian Nuclear Science and Technology Organisation. Research on the accelerator is divided between two groups, Accelerator Mass Spectrometry (AMS) and lon Beam Analysis (IBA). The IBA group carries out a range of research projects from nuclear physics to materials characterisation. The major IBA project on the accelerator is a recoil time-of-flight spectrometer which consists of two electrostatic time pulse generators and an ion-implanted surface barrier detector. The spectrometer is ideally suited to the profiling of layered multi-element materials, and has been used to characterise materials such as metal-germanides, optoelectronics, superconductors and catalytic converters. This paper will describe the time-of-flight system as well as some recent materials characterisation results. 1 refs., 3 figs.

The ANTARES recoil time-of-flight spectrometer

Energy Technology Data Exchange (ETDEWEB)

Martin, J W; Russell, G J [New South Wales Univ., Kensington, NSW (Australia); Cohen, D D; Dytlewski, N [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

1997-12-31

The Australian National Tandem for Applied Research (ANTARES), is a 8MV FN tandem particle accelerator at the Australian Nuclear Science and Technology Organisation. Research on the accelerator is divided between two groups, Accelerator Mass Spectrometry (AMS) and lon Beam Analysis (IBA). The IBA group carries out a range of research projects from nuclear physics to materials characterisation. The major IBA project on the accelerator is a recoil time-of-flight spectrometer which consists of two electrostatic time pulse generators and an ion-implanted surface barrier detector. The spectrometer is ideally suited to the profiling of layered multi-element materials, and has been used to characterise materials such as metal-germanides, optoelectronics, superconductors and catalytic converters. This paper will describe the time-of-flight system as well as some recent materials characterisation results. 1 refs., 3 figs.

A note on the random walk theory of recoil movement in prolonged ion bombardment

International Nuclear Information System (INIS)

Koponen, Ismo

1994-01-01

A characteristic function is derived for the probability distribution of final positions of recoil atoms in prolonged ion bombardment of dense matter. The derivation is done within the framework of Poissonian random walk theory using a jump distribution, which is somewhat more general than those studied previously. ((orig.))

Recoil-free Fraction in Amorphous and Nanocrystalline Aluminium Based Alloys

Science.gov (United States)

Sitek, Jozef

2008-10-01

Aluminium based rapidly quenched alloys of nominal composition Al90Fe7Nb3 and Al94Fe2V4 were studied by Mössbauer spectroscopy. We have measured the recoil-free fraction and thermal shift at room and liquid nitrogen temperature. The frequency modes of atomic vibrations were determined and consequently the characteristic Debye temperature was derived. Characteristic temperature calculated from f-factor was lower than those fitted from second order Doppler shift. This indicates the presence of different frequency modes for amorphous and nanocrystalline states.

The B → D*lv form factor at zero recoil

International Nuclear Information System (INIS)

Simone, J.N.; Hashimoto, S.; El-Khadra, A.X.; Kronfeld, A.S.; Mackenzie, P.B.; Ryan, S.M.

2000-01-01

We describe a model independent lattice QCD method for determining the deviation from unity for h A1 (1), the B → D*lv form factor at zero recoil. We extend the double ratio method previously used to determine the B → Dlv form factor. The bulk of statistical and systematic errors cancel in the double ratios we consider, yielding form factors which promise to reduce present theoretical uncertainties in the determination of parallel V cb parallel. We present results from a prototype calculation at a single lattice spacing corresponding to β = 5.7

Direct and Recoil-Induced Electron Emission from Ion-Bombarded Solids

DEFF Research Database (Denmark)

Holmen, G.; Svensson, B.; Schou, Jørgen

1979-01-01

The kinetic emission of secondary electrons from ion-bombarded solid surfaces is split into two contributions, a direct one caused by ionizing collisions between the bombarding ion and target atoms, and an indirect one originating from ionizing collisions undergone by recoil atoms with other target...... atoms. The direct contribution, which has been treated by several authors in previous studies, shows a behavior that is determined primarily by the electronic stopping power of the bombarding ion, while the indirect contribution is nonproportionally related to the nuclear stopping power. This latter...

Multiple scattering problems in heavy ion elastic recoil detection analysis

International Nuclear Information System (INIS)

Johnston, P.N.; El Bouanani, M.; Stannard, W.B.; Bubb, I.F.; Cohen, D.D.; Dytlewski, N.; Siegele, R.

1998-01-01

A number of groups use Heavy Ion Elastic Recoil Detection Analysis (HIERDA) to study materials science problems. Nevertheless, there is no standard methodology for the analysis of HIERDA spectra. To overcome this deficiency we have been establishing codes for 2-dimensional data analysis. A major problem involves the effects of multiple and plural scattering which are very significant, even for quite thin (∼100 nm) layers of the very heavy elements. To examine the effects of multiple scattering we have made comparisons between the small-angle model of Sigmund et al. and TRIM calculations. (authors)

Thin film analysis by instrumental heavy ion activation analysis using distributed recoil ranges of isotopic products

International Nuclear Information System (INIS)

Chowdhury, D.P.; Guin, R.; Saha, S.K.; Sudersanan, M.

2006-01-01

Thin foils (0.1 to 10 μm), metallic or polymeric, are frequently used in nuclear physics and chemistry experiments using ion beams from an accelerator. Very often it is important to know the major, minor and trace element composition of the foil. Several nuclear analytical techniques, namely RBS, ERDA, etc. are available for the near surface analysis. We have applied heavy ion activation analysis (HIAA) to explore the bulk composition of thin films. One of the difficulties in this method of thin film analysis is that the product nuclides from nuclear reaction come out of the sample surface due to high recoil energy. In thick sample, the recoiled nuclides are absorbed in the sample itself. This effect has been used to employ heavy ion activation for the analysis of thin films

Recoil measurement of the 12C(π(,πN))11C reaction between 90 and 350 MeV

International Nuclear Information System (INIS)

Porile, N.T.; Caretto, A.A.; Dropesky, B.J.; Orth, C.J.; Liu, L.C.; Giesler, G.C.

1984-01-01

The effective forward, perpendicular, and backward ranges of 11 C produced in the interaction of 90--350 MeV π +- with carbon have been measured using conventional thick-target thick-catcher activation techniques. With increasing pion energy, the forward ranges decrease, the backward ranges increase, and the perpendicular ranges remain essentially unchanged. However, these trends are much more pronounced for π - than for π + . The results have been compared with an intranuclear cascade code. The ratios of calculated effective ranges for π - and π + bombardment show the same energy dependence as observed experimentally

Comparative study of Monte Carlo particle transport code PHITS and nuclear data processing code NJOY for recoil cross section spectra under neutron irradiation

Energy Technology Data Exchange (ETDEWEB)

Iwamoto, Yosuke, E-mail: iwamoto.yosuke@jaea.go.jp; Ogawa, Tatsuhiko

2017-04-01

Because primary knock-on atoms (PKAs) create point defects and clusters in materials that are irradiated with neutrons, it is important to validate the calculations of recoil cross section spectra that are used to estimate radiation damage in materials. Here, the recoil cross section spectra of fission- and fusion-relevant materials were calculated using the Event Generator Mode (EGM) of the Particle and Heavy Ion Transport code System (PHITS) and also using the data processing code NJOY2012 with the nuclear data libraries TENDL2015, ENDF/BVII.1, and JEFF3.2. The heating number, which is the integral of the recoil cross section spectra, was also calculated using PHITS-EGM and compared with data extracted from the ACE files of TENDL2015, ENDF/BVII.1, and JENDL4.0. In general, only a small difference was found between the PKA spectra of PHITS + TENDL2015 and NJOY + TENDL2015. From analyzing the recoil cross section spectra extracted from the nuclear data libraries using NJOY2012, we found that the recoil cross section spectra were incorrect for {sup 72}Ge, {sup 75}As, {sup 89}Y, and {sup 109}Ag in the ENDF/B-VII.1 library, and for {sup 90}Zr and {sup 55}Mn in the JEFF3.2 library. From analyzing the heating number, we found that the data extracted from the ACE file of TENDL2015 for all nuclides were problematic in the neutron capture region because of incorrect data regarding the emitted gamma energy. However, PHITS + TENDL2015 can calculate PKA spectra and heating numbers correctly.

Hayabusa2 Sample Catcher and Container: Metal-Seal System for Vacuum Encapsulation of Returned Samples with Volatiles and Organic Compounds Recovered from C-Type Asteroid Ryugu

Science.gov (United States)

Okazaki, Ryuji; Sawada, Hirotaka; Yamanouchi, Shinji; Tachibana, Shogo; Miura, Yayoi N.; Sakamoto, Kanako; Takano, Yoshinori; Abe, Masanao; Itoh, Shoichi; Yamada, Keita; Yabuta, Hikaru; Okamoto, Chisato; Yano, Hajime; Noguchi, Takaaki; Nakamura, Tomoki; Nagao, Keisuke

2017-07-01

The spacecraft Hayabusa2 was launched on December 3, 2014, to collect and return samples from a C-type asteroid, 162173 Ryugu (provisional designation, 1999 JU3). It is expected that the samples collected contain organic matter and water-bearing minerals and have key information to elucidate the origin and history of the Solar System and the evolution of bio-related organics prior to delivery to the early Earth. In order to obtain samples with volatile species without terrestrial contamination, based on lessons learned from the Hayabusa mission, the sample catcher and container of Hayabusa2 were refined from those used in Hayabusa. The improvements include (1) a mirror finish of the inner wall surface of the sample catcher and the container, (2) adoption of an aluminum metal sealing system, and (3) addition of a gas-sampling interface for gas collection and evacuation. The former two improvements were made to limit contamination of the samples by terrestrial atmosphere below 1 Pa after the container is sealed. The gas-sampling interface will be used to promptly collect volatile species released from the samples in the sample container after sealing of the container. These improvements maintain the value of the returned samples.

B → Kl{sup +}l{sup -} decay at large hadronic recoil

Energy Technology Data Exchange (ETDEWEB)

Khodjamirian, Alexander; Mannel, Thomas [Siegen University (Germany); Wang, Yuming [TUM (Germany)

2013-07-01

We predict the amplitude of the B → Kl{sup +}l{sup -} decay in the region of the dilepton invariant mass squared 0 < q{sup 2}≤ m{sup 2}{sub J/ψ}, that is, at large hadronic recoil. The B → K form factors entering the factorizable part of the decay amplitude are obtained from QCD light-cone sum rules. The nonlocal effects, generated by the four-quark and penguin operators combined with the electromagnetic interaction, are calculated at q{sup 2}<0, far below the hadronic thresholds. For hard-gluon contributions we employ the QCD factorization approach. The soft-gluon nonfactorizable contributions are estimated from QCD light-cone sum rules. The result of the calculation is matched to the hadronic dispersion relation in the variable q{sup 2}, which is then continued to the kinematical region of the decay. The overall effect of nonlocal contributions in B → Kl{sup +}l{sup -} at large hadronic recoil is moderate. The main uncertainty of the predicted B → Kl{sup +}l{sup -} partial width is caused by the B → K form factors. Furthermore, the isospin asymmetry in this decay is expected to be very small. We investigate the deviation of the observables from the Standard Model predictions by introducing a generic new physics contribution to the effective Hamiltonian.

Effect of pressure on the radiation annealing of recoil atoms in chromates

International Nuclear Information System (INIS)

Stamouli, M.I.

1986-01-01

The effect of pressure on the annealing of recoil atoms by gamma radiation in neutron irradiated potassium chromate, ammonium chromate and ammonium dichromate was studied. In potassium chromate the pressure applied before the gamma-irradiation was found to retard the radiation annealing process. In ammonium chromate and ammonium dichromate the radiation annealing was found to be enhanced in the compressed samples in comparison to the noncompressed ones. (author)

The use of double-decker catcher bearing with face-to-face installed inner layer bearings

Science.gov (United States)

Zhu, Yi-Li; Zheng, Zhong-Qiao

2017-07-01

In active magnetic bearing (AMB) system, the catcher bearings (CB) are indispensable to temporarily support the rotor from directly impacting the stators. In most cases, traditional CB cannot bear the ultra-high speed, vibrations and impacts after a rotor drop event. To address the shortcomings, a double-decker ball bearing (DDBB) with inner two face-to-face angular contact ball bearings are proposed to be used as CB in an AMB system, and the dynamic response of the rotor after a rotor drop event is experimentally analyzed. The results indicate that using a DDBB as a CB helps to reduce the following collision forces after a rotor drop. Larger ball initial contact angles and smaller pre-load force on the inner layer bearings, larger radial clearance of the outer layer bearing and choosing AISI 10AISI 1045 steel which has a larger density for the adapter ring can effectively reduce the maximum impact force after a rotor drop event.

Automation of the helium jet transport system for nuclear recoil products

International Nuclear Information System (INIS)

Bellido, Luis F.; Pedrosa, Paulo S.

1996-09-01

A computer code and an interface hardware to automate the acquisition data and the sample changer in a helium jet transport system of recoil nucleus was developed for an IBM or compatible personal microcomputer. The software works with a Spectrum-ACE/ADCAM ORTEC's multichannel analysers and the interface card uses the 03EFh port to command the sample changer. This system allows to measure, by gamma spectrometry, radionuclides with half-lives of order of seconds produced from nuclear reactions. (author)

Oxygen recoil implant from SiO2 layers into single-crystalline silicon

International Nuclear Information System (INIS)

Wang, G.; Chen, Y.; Li, D.; Oak, S.; Srivastav, G.; Banerjee, S.; Tasch, A.; Merrill, P.; Bleiler, R.

2001-01-01

It is important to understand the distribution of recoil-implanted atoms and the impact on device performance when ion implantation is performed at a high dose through surface materials into single crystalline silicon. For example, in ultralarge scale integration impurity ions are often implanted through a thin layer of screen oxide and some of the oxygen atoms are inevitably recoil implanted into single-crystalline silicon. Theoretical and experimental studies have been performed to investigate this phenomenon. We have modified the Monte Carlo ion implant simulator, UT-Marlowe (B. Obradovic, G. Wang, Y. Chen, D. Li, C. Snell, and A. F. Tasch, UT-MARLOWE Manual, 1999), which is based on the binary collision approximation, to follow the full cascade and to dynamically modify the stoichiometry of the Si layer as oxygen atoms are knocked into it. CPU reduction techniques are used to relieve the demand on computational power when such a full cascade simulation is involved. Secondary ion mass spectrometry (SIMS) profiles of oxygen have been carefully obtained for high dose As and BF 2 implants at different energies through oxide layers of various thicknesses, and the simulated oxygen profiles are found to agree very well with the SIMS data. [copyright] 2001 American Institute of Physics

Ab initio molecular dynamics simulations of low energy recoil events in MgO

International Nuclear Information System (INIS)

Petersen, B. A.; Liu, B.; Weber, W. J.; Oak Ridge National Laboratory; Zhang, Y.; Oak Ridge National Laboratory

2017-01-01

In this paper, low-energy recoil events in MgO are studied using ab initio molecular dynamics simulations to reveal the dynamic displacement processes and final defect configurations. Threshold displacement energies, E_d, are obtained for Mg and O along three low-index crystallographic directions, [100], [110], and [111]. The minimum values for E_d are found along the [110] direction consisting of the same element, either Mg or O atoms. Minimum threshold values of 29.5 eV for Mg and 25.5 eV for O, respectively, are suggested from the calculations. For other directions, the threshold energies are considerably higher, 65.5 and 150.0 eV for O along [111] and [100], and 122.5 eV for Mg along both [111] and [100] directions, respectively. These results show that the recoil events in MgO are partial-charge transfer assisted processes where the charge transfer plays an important role. Finally, there is a similar trend found in other oxide materials, where the threshold displacement energy correlates linearly with the peak partial-charge transfer, suggesting this behavior might be universal in ceramic oxides.

The Final Merger of Massive Black Holes: Recoils, Gravitational Waves, and Electromagnetic Signatures

Science.gov (United States)

Centrella, Joan M.

2010-01-01

The final merger of two massive black holes produces a powerful burst of gravitational radiation, emitting more energy than all the stars in the observable universe combined. The resulting gravitational waveforms will be easily detectable by the space-based LISA out to redshifts z greater than 10, revealing the masses and spins of the black holes to high precision. If the merging black holes have unequal masses, or asymmetric spins, the final black hole that forms can recoil with a velocity exceeding 1000 km/s. And, when the black holes merge in the presence of gas and magnetic fields, various types of electromagnetic signals may also be produced. For more than 30 years, scientists have tried to compute black hole mergers using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. Within the past few years, however, this situation has changed dramatically, with a series of remarkable breakthroughs. This talk will focus on new results that are revealing the dynamics and waveforms of binary black hole mergers, recoil velocities, and the possibility of accompanying electromagnetic outbursts.

A new sliding joint to accommodate recoil of a free-piston-driven expansion tube facility

Science.gov (United States)

Gildfind, D. E.; Morgan, R. G.

2016-11-01

This paper describes a new device to decouple free-piston driver recoil and its associated mechanical vibration from the acceleration tube and test section of The University of Queensland's X3 expansion tube. A sliding joint is introduced to the acceleration tube which axially decouples the facility at this station. When the facility is fired, the upstream section of the facility, which includes the free-piston driver, can recoil upstream freely. The downstream acceleration tube remains stationary. This arrangement provides two important benefits. Firstly, it eliminates nozzle movement relative to the test section before and during the experiment. This has benefits in terms of experimental setup and alignment. Secondly, it prevents transmission of mechanical disturbances from the free-piston driver to the acceleration tube, thereby eliminating mechanically-induced transducer noise in the sensitive pressure transducers installed in this low-pressure tube. This paper details the new design, and presents experimental confirmation of its performance.

A study of CoSix silicide formed by recoil implantation

International Nuclear Information System (INIS)

Kwok, H.L.

1989-01-01

This work investigated the formation of CoSi x silicides on n-Si by recoil implantation through a thin cobalt layer using an inert gas ion beam. The results suggest the formation of a very shallow (35 to 45 nm) silicide surface layer under the specific conditions of preparation. The surface layer resistivity was comparable to values reported for Co 2 Si and CoSi, although below the surface, the resistivity decreased. This appeared to suggest a change-over from cobalt-rich silicides near the surface to a more conducting silicide (CoSi 2 ) at the interface. (author)

Gravitational-recoil effects on fermion propagation in space-time foam

CERN Document Server

Ellis, John R.; Nanopoulos, Dimitri V.; Volkov, G.

2000-01-01

Motivated by the possible experimental opportunities to test quantum gravity via its effects on high-energy neutrinos propagating through space-time foam, we discuss how to incorporate spin structures in our D-brane description of gravitational recoil effects in vacuo. We also point to an interesting analogous condensed-matter system. We use a suitable supersymmetrization of the Born-Infeld action for excited D-brane gravitational backgrounds to argue that energetic fermions may travel slower than the low-energy velocity of light: pulses of neutrinos at energies approaching 10^{19} eV: these would be observable only if M \\gsim 10^{27} GeV.

Recoil separators for radiative capture using radioactive ion beams. Recent advances and detection techniques

Energy Technology Data Exchange (ETDEWEB)

Ruiz, Chris [TRIUMF, Vancouver, BC (Canada); Greife, Uwe; Hager, Ulrike [Colorado School of Mines, Golden, CO (United States)

2014-06-15

Radiative capture reactions involving the fusion of hydrogen or helium are ubiquitous in the stellar history of the universe, and are some of the most important reactions in the processes that govern nucleosynthesis and energy generation in both static and explosive scenarios. However, radiative capture reactions pose some of the most difficult experimental challenges due to extremely small cross sections. With the advent of recoil separators and techniques in inverse kinematics, it is now possible to measure radiative capture reactions on very short-lived radioactive nuclei, and in the presence of high experimental backgrounds. In this paper we review the experimental needs for making measurements of astrophysical importance on radiative capture reactions. We also review some of the important historical advances in the field of recoil separators as well as describe current techniques and performance milestones, including descriptions of some of the separators most recently working at radioactive ion beam facilities, such as DRAGON at TRIUMF and the DRS at the Holifield Radioactive Ion Beam Facility. We will also summarize some of the scientific highlight measurements at the RIB facilities. (orig.)

Measurement of recoil photon polarisation in the electron-proton elastic scattering

International Nuclear Information System (INIS)

Buon, Jean

1965-02-01

This research thesis reports and discusses an experiment which aimed at checking the validity of the Born approximation at the first order in the elastic scattering of high energy electrons on protons. In this experiment, the recoil proton polarisation is measured in an elastic scattering of electrons with energy of 950 MeV and scattering at about 90 degrees in the mass centre system. The author describes the experimental installation, its operation and data collection, reports the analysis of photos and polarisation calculations and errors [fr

Adsorption of Hydrogen and Potassium on GaAs(110) Studied by Time-of-Flight Scattering and Recoiling Spectrometry

International Nuclear Information System (INIS)

Gayone, J.E.

2000-01-01

We study the adsorption of H and K on a GaAs(ll0) surface by Time-of-Flight Ion-Scattering (ISS) and Direct Recoiling (DRS) Spectrometry. The method for cleaning and preparation of the surface consists on cycles of grazing bombardment with 20 keV Ar+ combined with annealing. Since this is the first time that this method is applied to a semiconductor surface, the crystallographic structure of the grazing ion bombarded surface is first characterized by ISS and DRS. The variations of the projectile scattered intensity as a function of the incident and azimuthal angles are interpreted in terms of calculated shadowing and focusing effects. The crystallographic structure of the GaAs(ll0) surface prepared by this method presents the surface relaxation observed for cleaved surfaces. The adsorption of H on GaAs(ll0) is studied as a function of the H 2 exposure and the surface temperature.The behavior of the intensity of projectiles scattered from the first two As and Ga layers is consistent with a process of unrelaxation towards the ideal surface termination upon H adsorption. We have determined that for exposures of 1000 L and 2000 L the AsI-GaI splitting corresponding to the unrelaxed surface is reduced to ΔZ = (0.0 n 0.08) A, as it should be expected for the bulk terminated surface. In addition, the fraction of the surface remaining relaxed as in the clean surface decreases strongly with the H 2 exposure. The H atoms adsorbed on the surface can be detected as recoils produced in quasi-single collisions allowing the study of the adsorption kinetics. The variations of the H recoil intensity with the exposure show that the sticking coefficient changes strongly with the H coverage since the beginning the adsorption. Above ∼ 500 L, the adsorption kinetics deviates from the initial behavior and the sticking coefficient becomes almost constant and small. The simultaneous measurements of the H coverage (with DRS) and the changes in the atomic structure (with ISS) as a

Recent recoil ion momentum spectroscopy experiments at KSU

International Nuclear Information System (INIS)

Abdallah, M.; Cocke, C.L.; Kravis, S.; Montenegro, E.C.; Moshammer, R.; Saleh, L.; Ullrich, J.; Varghese, S.L.; Wolff, W.; Wolf, H.

1997-01-01

Recoil momentum spectroscopy is used to study collisions involving both fast and slow projectiles on He targets. Experiments have been performed on electron capture and loss from fast ions from the KSU LINAC and slow ions from the KSU CRYEBIS using a supersonic jets with a momentum resolution below 0.5 au. Using fast ions, the final states populated in electron capture from He by 10 MeV F 8+ have been resolved with a Q-value resolution of 18 eV, sufficient to separate final channels in which the He + ion is left excited from those in which He + is left in its ground state. With slow ions, electron capture from He by slow bare Ne ions has been studied. A few recent results are discussed. copyright 1997 American Institute of Physics

Natural alpha recoil particle radiation and ionizing radiation sensitivities in quartz detected with EPR: implications for geochronometry

International Nuclear Information System (INIS)

Rink, W.J.; Odom, A.L.

1991-01-01

The electron paramagnetic resonance EPR signals in granitic quartz samples of known age are studied. Time-integrated alpha recoil activity and EPR signal intensity are more significantly correlated than sample age and EPR signal intensity. Neutron activation analysis for internal uranium and thorium in quartz are reported. Natural germanium EPR signals are observed in pegmatitic quartz samples and one granitic quartz. Pegmatitic quartz exhibits germanium EPR center growth competing strongly with E' center growth, apparently leading to depleted natural concentrations of E' centers. Calculations of lattice vacancy accumulation associated with alpha recoil damage are presented and compared with concentrations of paramagnetic oxygen vacancies in the quartz. Based on the results reported, the potential and problems associated with dating quartz are discussed, relating both to accumulated lattice damage and the additive dose methods. (author)

Development of phonon-mediated cryogenic particle detectors with electron and nuclear recoil discrimination

Science.gov (United States)

Nam, Sae Woo

1999-10-01

Observations have shown that galaxies, including our own, are surrounded by halos of ``dark matter''. One possibility is that this may be an undiscovered form of matter, weakly interacting massive particles (WIMPs). This thesis describes the development of silicon based cryogenic particle detectors designed to directly detect interactions with these WIMPs. These detectors are part of a new class of detectors which are able to reject background events by simultaneously measuring energy deposited into phonons versus electron hole pairs. By using the phonon sensors with the ionization sensors to compare the partitioning of energy between phonons and ionizations we can discriminate between electron recoil events (background radiation) and nuclear recoil events (dark matter events). These detectors with built-in background rejection are a major advance in background rejection over previous searches. Much of this thesis will describe work in scaling the detectors from / g prototype devices to a fully functional prototype 100g dark matter detector. In particular, many sensors were fabricated and tested to understand the behavior of our phonon sensors, Quasipartice trapping assisted Electrothermal feedback Transition edge sensors (QETs). The QET sensors utilize aluminum quasiparticle traps attached to tungsten superconducting transition edge sensors patterned on a silicon substrate. The tungsten lines are voltage biased and self-regulate in the transition region. Phonons from particle interactions within the silicon propogate to the surface where they are absorbed by the aluminum generating quasiparticles in the aluminum. The quasiparticles diffuse into the tungsten and couple energy into the tungsten electron system. Consequently, the tungsten increases in resistance and causes a current pulse which is measured with a high bandwidth SQUID system. With this advanced sensor technology, we were able to demonstrate detectors with xy position sensitivity with electron and

The DarkSide-50 Experiment: Electron Recoil Calibrations and A Global Energy Variable

Energy Technology Data Exchange (ETDEWEB)

Hackett, Brianne Rae [Hawaii U.

2017-01-01

Over the course of decades, there has been mounting astronomical evidence for non-baryonic dark matter, yet its precise nature remains elusive. A favored candidate for dark matter is the Weakly Interacting Massive Particle (WIMP) which arises naturally out of extensions to the Standard Model. WIMPs are expected to occasionally interact with particles of normal matter through nuclear recoils. DarkSide-50 aims to detect this type of particle through the use of a two-phase liquid argon time projection chamber. To make a claim of discovery, an accurate understanding of the background and WIMP search region is imperative. Knowledge of the backgrounds is done through extensive studies of DarkSide-50's response to electron and nuclear recoils. The CALibration Insertion System (CALIS) was designed and built for the purpose of introduc- ing radioactive sources into or near the detector in a joint eort between Fermi National Laboratory (FNAL) and the University of Hawai'i at Manoa. This work describes the testing, installation, and commissioning of CALIS at the Laboratori Nazionali del Gran Sasso. CALIS has been used in mul- tiple calibration campaigns with both neutron and sources. In this work, DarkSide-50's response to electron recoils, which are important for background estimations, was studied through the use of calibration sources by constructing a global energy variable which takes into account the anti- correlation between scintillation and ionization signals produced by interactions in the liquid argon. Accurately reconstructing the event energy correlates directly with quantitatively understanding the WIMP sensitivity in DarkSide-50. This work also validates the theoretically predicted decay spectrum of 39Ar against 39Ar decay data collected in the early days of DarkSide-50 while it was lled with atmospheric argon; a validation of this type is not readily found in the literature. Finally, we show how well the constructed energy variable can predict

Segmented detector for recoil neutrons in the p(γ, n)π+ reaction

International Nuclear Information System (INIS)

Korkmaz, E.; O'Rielly, G.V.; Hutcheon, D.A.; Feldman, G.; Jordan, D.; Kolb, N.R.; Pywell, R.E.; Retzlaff, G.A.; Sawatzky, B.D.; Skopik, D.M.; Vogt, J.M.; Cairns, E.; Giesen, U.; Holm, L.; Opper, A.K.; Rozon, F.M.; Soukup, J.

1999-01-01

A segmented neutron detector has been constructed and used for recoil neutron (6-13 MeV) measurements of the reaction γp→nπ + very close to threshold. BC-505 liquid scintillator was used to allow pulse shape discrimination between neutrons and photons. A measurement of the absolute efficiency of the detector was performed using stopped pions in the reaction π - p→nγ. Results of the efficiency calibration are compared to a Monte Carlo simulation. (author)

The Dialectic: Not just the Absolute Recoil, but the World’s Living Fire that Extinguishes and Kindles Itself. Reflections on Slavoj Žižek’s Version of Dialectical Philosophy in "Absolute Recoil: Towards a New Foundation of Dialectical Materialism".

Directory of Open Access Journals (Sweden)

Christian Fuchs

2014-10-01

Full Text Available Slavoj Žižek shows in his book Absolute Recoil (and previous Hegelian works such as Less than Nothing the importance of repeating Hegel’s dialectical philosophy in contemporary capitalism. Žižek contributes especially to a reconceptualisation of dialectical logic and based on it the dialectic of history. The reflections in this paper stress that the dialectic is only the absolute recoil, a sublation that posits its own presuppositions, by working as a living fire that extinguishes and kindles itself. I point out that a new foundation of dialectical materialism needs a proper Heraclitusian foundation. I discuss Žižek’s version of the dialectic that stresses the absolute recoil and the logic of retroactivity and point out its implications for the concept of history as well as Žižek’s own theoretical ambiguities that oscillate between postmodern relativism and mechanical materialism. I argue that Žižek’s version of the dialectic should be brought into a dialogue with the dialectical philosophies of the German Marxists Hans Heinz Holz and Herbert Hörz. Žižek’s achievement is that he helps keeping alive the fire of dialectical materialism in the 21st century. Such a dialectical fire is needed for a proper revolutionary theory.

Cold-target recoil-ion momentum-spectroscopy: First results and future perspectives of a novel high resolution technique for the investigation of collision induced many-particle reactions

International Nuclear Information System (INIS)

Ullrich, J.; Doerner, R.; Mergel, V.; Jagutzki, O.; Spielberger, L.; Schmidt-Boecking, H.

1994-09-01

In order to investigate many-particle reaction dynamics in atomic collisions a novel high-resolution technique has been developed, which determines the momentum and the charge state of the slowly recoiling target ions. Using a very cold, thin, and localized supersonic gas jet target a momentum resolution of better than 0.05 a.u. is obtained by measuring the recoil-ion time-of-flight and the recoil-ion trajectory. Because of the very high detection efficiency of nearly 100% this technique is well suited for many-particle coincidence measurements in ionizing collisions. First experimental results for fast ion and electron impact on helium targets are presented. Future applications in atomic collision physics and related areas are discussed. (orig.)

Chemical effects of 13N produced by recoil protons and deuterons in pile-irradiated methanol and methanol-d4

International Nuclear Information System (INIS)

Sensui, Y.; Tomura, K.; Matsuura, T.

1982-01-01

The stabilized chemical forms of 13 N resulting from the reactions 13 C(p,n) 13 N by a recoil proton and 12 C(d,n) 13 N by a recoil deuteron, were studied in pile-irradiated methanol and methanol-d 4 in the temperature range from 77 to 295 K. Contrary to the target of benzene, cyclohexane, acetone and diethyl ether previously studied, the relative yield of 13 N-compounds did not depend on the irradiation temperature in the present media. In the yield of 13 N-compounds no marked change was observed between methanol and methanol-d 4 , differing from the results between benzene and benzene-d 6 . A mechanism is proposed to explain the results. (author)

Determination of lifetimes of nuclear excited states using the Recoil Distance Doppler Shift Method in combination with magnetic spectrometers

Energy Technology Data Exchange (ETDEWEB)

Doncel, M. [Universidad de Salamanca, Laboratorio de Radiaciones Ionizantes, Salamanca (Spain); Royal Institute of Technology, Department of Physics, Stockholm (Sweden); University of Liverpool, Department of Physics, Oliver Lodge Laboratory, Liverpool (United Kingdom); Gadea, A. [CSIC-University of Valencia, Istituto de Fisica Corpuscular, Valencia (Spain); Valiente-Dobon, J.J. [INFN, Laboratori Nazionali di Legnaro, Legnaro (Italy); Quintana, B. [Universidad de Salamanca, Laboratorio de Radiaciones Ionizantes, Salamanca (Spain); Modamio, V. [INFN, Laboratori Nazionali di Legnaro, Legnaro (Italy); University of Oslo, Oslo (Norway); Mengoni, D. [Dipartimento di Fisica e Astronomia, Universita di Padova, Padova (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Padova, Padova (Italy); Moeller, O.; Pietralla, N. [Technische Universitaet Darmstadt, Institut fuer Kernphysik, Darmstadt (Germany); Dewald, A. [Institut fuer Kernphysik, Universitaet Koeln (Germany)

2017-10-15

The current work presents the determination of lifetimes of nuclear excited states using the Recoil Distance Doppler Shift Method, in combination with spectrometers for ion identification, normalizing the intensity of the peaks by the ions detected in the spectrometer as a valid technique that produces results comparable to the ones obtained by the conventional shifted-to-unshifted peak ratio method. The technique has been validated using data measured with the γ-ray array AGATA, the PRISMA spectrometer and the Cologne plunger setup. In this paper a test performed with the AGATA-PRISMA setup at LNL and the advantages of this new approach with respect to the conventional Recoil Distance Doppler Shift Method are discussed. (orig.)

Observation of fission residues in the 16O + 181Ta system at Elab ≈ 6 MeV/A

Directory of Open Access Journals (Sweden)

Singh B. P.

2011-10-01

Full Text Available Present paper reports on the production cross-section of 24 fission like events (30 ≤ Z ≤ 60 formed via complete fusion-fission and/or incomplete fusion-fission processes in 16O+181Ta system at energies ≈ 6 MeV/A. Experiments have been performed using the recoil-catcher technique followed by off-line γ-spectroscopy. The measured cross-section of fission-like events is satisfactorily described by a statistical model code. Further, an attempt has been made to study the mass and isotopic yield distributions of fission fragments. The variance of the presently measured isotopic yield distributions has been found to be in agreement with the literature values for some other fissioning systems.

Molecular catchers for pharmacologically active substances in wastewaters, a theoretical study

International Nuclear Information System (INIS)

Salazar Valencia, P J; Pérez Merchancano, S T; Bolívar Marinez, L E; Paredes, H

2016-01-01

A basic and pressing need in the treatment of residual waste waters for urban and rural centers is the removal of pharmacological active residues from them, these resides are originated in a wide array of domestic, agricultural and industrial sources and can't be removed in the residual waters treatment plants by conventional methods, the result is the incorporation of them into the ecosystem altering the physiology and behavior of living organisms. Among the most active pharmacological substances found in very high concentration in residual waters is paracetamol, an analgesic of very wide excessive use due to its ease of access and low cost [1]. No pharmacological substance is entirely absorbed by the human organism and therefore a wide family of molecular residues is excreted by the urinary tract. In this work we have used the AM1 (Austin Model 1), PM3 (Parametric Method 3) and ZINDO/CI semiempirical methods, from the NDO (Neglect Differential Overlap) family [2] to study and observe the structural, electronic and optical characteristics of paracetamol while immersed in different basic and acidic aqueous environments, either alone or interacting with lignosulphonates. We have previously found that lignosulphonates, a lignin derivatives of wide industrial applications, can be engineered as a binding and flocculant agent and acts as molecular catchers therefore showing the potential to be used as a mean to filter and eliminate molecular residues from the residual waters [3]. (paper)

Control of recoil losses in nanomechanical SiN membrane resonators

Science.gov (United States)

Borrielli, A.; Marconi, L.; Marin, F.; Marino, F.; Morana, B.; Pandraud, G.; Pontin, A.; Prodi, G. A.; Sarro, P. M.; Serra, E.; Bonaldi, M.

2016-09-01

In the context of a recoil damping analysis, we have designed and produced a membrane resonator equipped with a specific on-chip structure working as a "loss shield" for a circular membrane. In this device the vibrations of the membrane, with a quality factor of 107, reach the limit set by the intrinsic dissipation in silicon nitride, for all the modes and regardless of the modal shape, also at low frequency. Guided by our theoretical model of the loss shield, we describe the design rationale of the device, which can be used as effective replacement of commercial membrane resonators in advanced optomechanical setups, also at cryogenic temperatures.

Calibration of a compact magnetic proton recoil neutron spectrometer

Energy Technology Data Exchange (ETDEWEB)

Zhang, Jianfu, E-mail: zhang_jianfu@163.com [School of Nuclear Science and Technology, Xi' an Jiaotong University, Xi' an 710049 (China); Northwest Institute of Nuclear Technology, Xi' an 710024 (China); Ouyang, Xiaoping; Zhang, Xianpeng [School of Nuclear Science and Technology, Xi' an Jiaotong University, Xi' an 710049 (China); Northwest Institute of Nuclear Technology, Xi' an 710024 (China); Ruan, Jinlu [Northwest Institute of Nuclear Technology, Xi' an 710024 (China); Zhang, Guoguang [Applied Institute of Nuclear Technology, China Institute of Atomic Energy, Beijing 102413 (China); Zhang, Xiaodong [Northwest Institute of Nuclear Technology, Xi' an 710024 (China); Qiu, Suizheng, E-mail: szqiu@mail.xjtu.edu.cn [School of Nuclear Science and Technology, Xi' an Jiaotong University, Xi' an 710049 (China); Chen, Liang; Liu, Jinliang; Song, Jiwen; Liu, Linyue; Yang, Shaohua [Northwest Institute of Nuclear Technology, Xi' an 710024 (China)

2016-04-21

Magnetic proton recoil (MPR) neutron spectrometer is considered as a powerful instrument to measure deuterium–tritium (DT) neutron spectrum, as it is currently used in inertial confinement fusion facilities and large Tokamak devices. The energy resolution (ER) and neutron detection efficiency (NDE) are the two most important parameters to characterize a neutron spectrometer. In this work, the ER calibration for the MPR spectrometer was performed by using the HI-13 tandem accelerator at China Institute of Atomic Energy (CIAE), and the NDE calibration was performed by using the neutron generator at CIAE. The specific calibration techniques used in this work and the associated accuracies were discussed in details in this paper. The calibration results were presented along with Monte Carlo simulation results.

Influence of crystal defects on the chemical reactivity of recoil atoms in oxygen-containing chromium compounds

International Nuclear Information System (INIS)

Costea, T.

1969-01-01

The influence of crystal defects on the chemical reactivity of recoil atoms produced by the reaction 50 Cr (n,γ) 51 Cr in oxygen-containing chromium compounds has been studied. Three methods have been used to introduce the defects: doping (K 2 CrO 4 doped with BaCrO 4 ), irradiation by ionizing radiation (K 2 CrO 4 irradiated in the presence of Li 2 CO 3 ) and non-stoichiometry (the semi-conducting oxides of the CrO 3 -Cr 2 O 3 series). The thermal annealing kinetics of the irradiated samples have been determined, and the activation energy has been calculated. In all cases it has been observed that there is a decrease in the activation energy for thermal annealing in the presence of the defects. In order to explain the annealing process, an electronic mechanism has been proposed based on the interaction between the recoil species and the charge-carriers (holes or electrons). (author) [fr

Neutron spectrometry for D-T plasmas in JET, using a tandem annular-radiator proton-recoil spectrometer

Energy Technology Data Exchange (ETDEWEB)

Hawkes, N.P.; Bond, D.S.; Kiptily, V.; Jarvis, O.N. E-mail: onj@jet.uk; Conroy, S.W

2002-01-01

A selection of the 14-MeV neutron spectra obtained at the JET Joint Undertaking tokamak during the deuterium-tritium operating campaign in 1997 are presented and analyzed. While several neutron spectrometers were operational during this campaign, the present paper is concerned solely with one: the tandem annular-radiator proton-recoil spectrometer (or proton recoil telescope, for brevity). During neutral beam heating with combined d- and t-beams, analysis of the spectra can define the core fuel composition (D:T) ratio. The spectra are sensitive to the population balance of the fast ions streaming in directions parallel and opposite to that of the injected beams. During ICRF heating of minority deuterium in bulk tritium plasmas, the spectra provide measurements of the effective temperature of the fast-deuteron energy tail and of its relative strength, which vary with the deuterium concentration. This information contributes to the overall understanding of the fusion performance of the various operating scenarios.

Conception of a New Recoil Proton Telescope for Real-Time Neutron Spectrometry in Proton-Therapy

Science.gov (United States)

Combe, Rodolphe; Arbor, Nicolas; el Bitar, Ziad; Higueret, Stéphane; Husson, Daniel

2018-01-01

Neutrons are the main type of secondary particles emitted in proton-therapy. Because of the risk of secondary cancer and other late occurring effects, the neutron dose should be included in the out-of-field dose calculations. A neutron spectrometer has to be used to take into account the energy dependence of the neutron radiological weighting factor. Due to its high dependence on various parameters of the irradiation (beam, accelerator, patient), the neutron spectrum should be measured independently for each treatment. The current reference method for the measurement of the neutron energy, the Bonner Sphere System, consists of several homogeneous polyethylene spheres with increasing diameters equipped with a proportional counter. It provides a highresolution reconstruction of the neutron spectrum but requires a time-consuming work of signal deconvolution. New neutron spectrometers are being developed, but the main experimental limitation remains the high neutron flux in proton therapy treatment rooms. A new model of a real-time neutron spectrometer, based on a Recoil Proton Telescope technology, has been developed at the IPHC. It enables a real-time high-rate reconstruction of the neutron spectrum from the measurement of the recoil proton trajectory and energy. A new fast-readout microelectronic integrated sensor, called FastPixN, has been developed for this specific purpose. A first prototype, able to detect neutrons between 5 and 20 MeV, has already been validated for metrology with the AMANDE facility at Cadarache. The geometry of the new Recoil Proton Telescope has been optimized via extensive Geant4 Monte Carlo simulations. Uncertainty sources have been carefully studied in order to improve simultaneously efficiency and energy resolution, and solutions have been found to suppress the various expected backgrounds. We are currently upgrading the prototype for secondary neutron detection in proton therapy applications.

Possibility of obtaining enriched americium-242g by the elution of recoil atoms from zeolite

Energy Technology Data Exchange (ETDEWEB)

Shafiev, A I; Vityutnev, V M; Ivanov, V M; Yakovlev, G N

1974-12-31

On the example of production the possibility of obtaining enriched actinide isotopes by the elution of recotl atoms with the use of a zeolite- americium-241 target was shown. The enrichment factor and the recoil atoms of / sup 242g/Am yield depend on preliminary target treatment and solution composition used for elution. (auth)

LISA detection of massive black hole binaries: imprint of seed populations and extreme recoils

International Nuclear Information System (INIS)

Sesana, A; Volonteri, M; Haardt, F

2009-01-01

All the physical processes involved in the formation, merging and accretion history of massive black holes along the hierarchical build-up of cosmic structures are likely to leave an imprint on the gravitational waves detectable by future space-borne missions, such as LISA. We report here the results of recent studies, carried out by means of dedicated simulations of black hole build-up, aiming at understanding the impact on LISA observations of two ingredients that are crucial in every massive black hole formation scenario, namely: (i) the nature and abundance of the first black hole seeds and (ii) the large gravitational recoils following the merger of highly spinning black holes. We predict LISA detection rates spanning two orders of magnitude, in the range 3-300 events per year, depending on the detail of the assumed massive black hole seed model. On the other hand, large recoil velocities do not dramatically compromise the efficiency of LISA observations. The number of detections may drop substantially (by ∼60%), in scenarios characterized by abundant light seeds, but if seeds are already massive and/or relatively rare, the detection rate is basically unaffected.

Gravitational-wave memory revisited: Memory from the merger and recoil of binary black holes

International Nuclear Information System (INIS)

Favata, Marc

2009-01-01

Gravitational-wave memory refers to the permanent displacement of the test masses in an idealized (freely-falling) gravitational-wave interferometer. Inspiraling binaries produce a particularly interesting form of memory-the Christodoulou memory. Although it originates from nonlinear interactions at 2.5 post-Newtonian order, the Christodoulou memory affects the gravitational-wave amplitude at leading (Newtonian) order. Previous calculations have computed this non-oscillatory amplitude correction during the inspiral phase of binary coalescence. Using an 'effective-one-body' description calibrated with the results of numerical relativity simulations, the evolution of the memory during the inspiral, merger, and ringdown phases, as well as the memory's final saturation value, are calculated. Using this model for the memory, the prospects for its detection are examined, particularly for supermassive black hole binary coalescences that LISA will detect with high signal-to-noise ratios. Coalescing binary black holes also experience center-of-mass recoil due to the anisotropic emission of gravitational radiation. These recoils can manifest themselves in the gravitational-wave signal in the form of a 'linear' memory and a Doppler shift of the quasi-normal-mode frequencies. The prospects for observing these effects are also discussed.

COREL, Ion Implantation in Solids, Range, Straggling Using Thomas-Fermi Cross-Sections. RASE4, Ion Implantation in Solids, Range, Straggling, Energy Deposition, Recoils. DAMG2, Ion Implantation in Solids, Energy Deposition Distribution with Recoils

International Nuclear Information System (INIS)

Brice, D. K.

1979-01-01

1 - Description of problem or function: COREL calculates the final average projected range, standard deviation in projected range, standard deviation in locations transverse to projected range, and average range along path for energetic atomic projectiles incident on amorphous targets or crystalline targets oriented such that the projectiles are not incident along low index crystallographic axes or planes. RASE4 calculates the instantaneous average projected range, standard deviation in projected range, standard deviation in locations transverse to projected range, and average range along path for energetic atomic projectiles incident on amorphous targets or crystalline targets oriented such that the projectiles are not incident along low index crystallographic axes or planes. RASE4 also calculates the instantaneous rate at which the projectile is depositing energy into atomic processes (damage) and into electronic processes (electronic excitation), the average range of target atom recoils projected onto the direction of motion of the projectiles, and the standard deviation in the recoil projected range. DAMG2 calculates the distribution in depth of the energy deposited into atomic processes (damage), electronic processes (electronic excitation), or other energy-dependent quality produced by energetic atomic projectiles incident on amorphous targets or crystalline targets oriented such that the projectiles are not incident along low index crystallographic axes or planes. 2 - Method of solution: COREL: The truncated differential equation which governs the several variables being sought is solved through second-order by trapezoidal integration. The energy-dependent coefficients in the equation are obtained by rectangular integration over the Thomas-Fermi elastic scattering cross section. RASE4: The truncated differential equation which governs the range and straggling variables is solved through second-order by trapezoidal integration. The energy

Light output response of EJ-309 liquid organic scintillator to 2.86-3.95 MeV carbon recoil ions due to neutron elastic and inelastic scatter

Science.gov (United States)

Norsworthy, Mark A.; Ruch, Marc L.; Hamel, Michael C.; Clarke, Shaun D.; Hausladen, Paul A.; Pozzi, Sara A.

2018-03-01

We present the first measurements of energy-dependent light output from carbon recoils in the liquid organic scintillator EJ-309. For this measurement, neutrons were produced by an associated particle deuterium-tritium generator and scattered by a volume of EJ-309 scintillator into stop detectors positioned at four fixed angles. Carbon recoils in the scintillator were isolated using triple coincidence among the associated particle detector, scatter detector, and stop detectors. The kinematics of elastic and inelastic scatter allowed data collection at eight specific carbon recoil energies between 2.86 and 3.95 MeV. We found the light output caused by carbon recoils in this energy range to be approximately 1.14% of that caused by electrons of the same energy, which is comparable to the values reported for other liquid organic scintillators. A comparison of the number of scattered neutrons at each angle to a Monte Carlo N-Particle eXtended simulation indicates that the ENDF/B-VII.1 evaluation of differential cross sections for 14.1 MeV neutrons on carbon has discrepancies with the experiment as large as 55%, whereas those reported in the JENDL-4.0u evaluation agree with experiment.

The study of the ion-crystal interaction by using the blocking technique for scattered recoils

International Nuclear Information System (INIS)

Karamyan, S.A.

1989-01-01

Experimental data are presented on the orientation effects observed in the fast heavy ion irradiated diamond, Si and Ge crystals by recording recoil nuclei. The volume capture of medium-weight nuclei to channeling has first been revealed and studied. Ion damaging power is systematized and the anomalously low damaging power is Xe ions is established. 18 refs.; 9 figs

Binary and Recoil Collisions in Strong Field Double Ionization of Helium

International Nuclear Information System (INIS)

Staudte, A.; Villeneuve, D. M.; Corkum, P. B.; Ruiz, C.; Becker, A.; Schoeffler, M.; Schoessler, S.; Meckel, M.; Doerner, R.; Zeidler, D.; Weber, Th.

2007-01-01

We have investigated the correlated momentum distribution of both electrons from nonsequential double ionization of helium in a 800 nm, 4.5x10 14 W/cm 2 laser field. Using very high resolution coincidence techniques, we find a so-far unobserved fingerlike structure in the correlated electron momentum distribution. The structure can be interpreted as a signature of the microscopic dynamics in the recollision process. We identify features corresponding to the binary and recoil lobe in field-free (e,2e) collisions. This interpretation is supported by analyzing ab initio solutions of a fully correlated three-dimensional helium model

The XMM-Newton spectrum of a candidate recoiling supermassive black hole: An elusive inverted P-Cygni profile

Energy Technology Data Exchange (ETDEWEB)

Lanzuisi, G.; Civano, F.; Marchesi, S.; Hickox, R. [Department of Physics and Astronomy, Dartmouth College, Wilder Laboratory, Hanover, NH 03855 (United States); Comastri, A.; Cappelluti, N. [INAF-Osservatorio Astronomico di Bologna, via Ranzani 1, I-40127 Bologna (Italy); Costantini, E. [SRON, Netherlands Institute for Space Research, Sorbonnelaan, 2, 3584 CA Utrecht (Netherlands); Elvis, M.; Fruscione, A. [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States); Mainieri, V. [European Southern Observatory, Karl-Schwarschild-Strasse 2, D-85748 Garching bei Munchen (Germany); Jahnke, K. [Max Planck Institute for Astronomy, Konigstuhl 17, D-69117 Heidelberg (Germany); Komossa, S. [Max-Planck-Institut fuer Radioastronomie, Auf dem Huegel 69, D-53121 Bonn (Germany); Piconcelli, E. [INAF-Osservatorio Astronomico di Roma, via Frascati 33, I-00040 Monteporzio Catone (Italy); Vignali, C.; Brusa, M. [Dipartimento di Astronomia, Universitá degli Studi di Bologna, via Ranzani 1, I-40127 Bologna (Italy)

2013-11-20

We present a detailed spectral analysis of new XMM-Newton data of the source CXOC J100043.1+020637, also known as CID-42, detected in the COSMOS survey at z = 0.359. Previous works suggested that CID-42 is a candidate recoiling supermassive black hole (SMBH) showing also an inverted P-Cygni profile in the X-ray spectra at ∼6 keV (rest) with an iron emission line plus a redshifted absorption line (detected at 3σ in previous XMM-Newton and Chandra observations). Detailed analysis of the absorption line suggested the presence of ionized material flowing into the black hole at high velocity. In the new long XMM-Newton observation, while the overall spectral shape remains constant, the continuum 2-10 keV flux decrease of ∼20% with respect to previous observation and the absorption line is undetected. The upper limit on the intensity of the absorption line is EW < 162 eV. Extensive Monte Carlo simulations show that the nondetection of the line is solely due to variation in the properties of the inflowing material, in agreement with the transient nature of these features, and that the intensity of the line is lower than the previously measured with a probability of 98.8%. In the scenario of CID-42 as a recoiling SMBH, the absorption line can be interpreted as being due to an inflow of gas with variable density that is located in the proximity of the SMBH and recoiling with it. New monitoring observations will be requested to further characterize this line.

Experimental investigation of the triple differential cross section for electron impact ionization of N{sub 2} and CO{sub 2} molecules at intermediate impact energy and large ion recoil momentum

Energy Technology Data Exchange (ETDEWEB)

Lahmam-Bennani, A; Staicu Casagrande, E M; Naja, A, E-mail: azzedine.bennani@u-psud.f [Universite Paris-Sud 11, Laboratoire des Collisions Atomiques et Moleculaires (LCAM), Bat. 351, 91405 Orsay Cedex (France)

2009-12-14

The (e,2e) triple differential cross sections (TDCS) are measured for the ionization of nitrogen and carbon dioxide molecules in a coplanar asymmetric geometry for a wide range of ejected electron energies and at an incident energy about 500-700 eV. This kinematics corresponds to a large momentum imparted to the ion, and is meant to enhance the recoil scattering. The experimental binary and recoil angular distributions of the TDCS are characterized both by a shift towards larger angles with respect to the momentum transfer direction and by a large intensity in the recoil region, in particular for the ionization of the 'inner' N{sub 2}(2{sigma}{sub g}) molecular orbital. The data are compared with the results of calculations using the first Born approximation-two centre continuum (FBA-TCC) theoretical model for treating differential electron impact ionization. The experimentally observed shifts and recoil intensity enhancement are not predicted by the model calculations, which rather yield a TDCS symmetrically distributed around the momentum transfer direction, and completely fail in describing the recoil distribution. It is hoped that these new results will stimulate the development of more refined theories for correctly modelling single ionization of molecules.

Monte-Carlo simulation of heavy ion elastic recoil detection analysis data to include the effects of large angle plural scattering

International Nuclear Information System (INIS)

Johnston, P.N.; Franich, R.D.

1999-01-01

Heavy Ion Elastic Recoil Detection Analysis (HIERDA) is becoming widely used to study a range of problems in materials science, however there is no standard methodology for the analysis of HIERDA spectra. Major impediments are the effects of multiple and plural scattering which are very significant, even for quite thin (∼100nm) layers of very heavy elements. To examine the effects of multiple scattering a fast FORTRAN version of TRIM has been adapted to simulate the spectrum of backscattered and recoiled ions reaching the detector. Two problems have been initially investigated. In the first, the detector is positioned beyond the critical angle for single scattering from a pure vanadium target where traditional slab analysis would not predict any scattered yield. In the second, a thin Au layer on a Si substrate is modelled for two different thicknesses of the substrate to investigate the effect of the substrate chosen. The use of multiple processors enabled the acquisition of statistically reasonable simulation spectra for scattered and recoiled ions. For each target modelled, 10 9 incident ions were tracked. The results of the simulations are compared with experimental measurements performed using ToF-E HIERDA at Lucas Heights and show good agreement except in the long tails due to Plural Scattering

Production of highly ionized recoil ions in heavy ion impact

International Nuclear Information System (INIS)

Tawara, H.; Tonuma, T.; Be, S.H.; Shibata, H.; Kase, M.; Kambara, T.; Kumagai, H.; Kohno, I.

1985-01-01

The production mechanisms of highly ionized recoil ions in energetic, highly charged heavy ion impact are compared with those in photon and electron impact. In addition to the innershell ionization processes which are important in photon and electron impact, the electron transfer processes are found to play a key role in heavy ion impact. In molecular targets are also observed highly ionized monoatomic ions which are believed to be produced through production of highly ionized molecular ions followed by prompt dissociation. The observed N 6+ ions produced in 1.05MeV/amu Ar 12+ ions on N 2 molecules are produced through, for example, N 2 12+ *→N 6+ +N 6+ process. (author)

Electric form factor of the proton through recoil polarization

International Nuclear Information System (INIS)

Punjabi, V.

2000-01-01

The electromagnetic form factors of the nucleon, G E and G M , describe the charge and current distribution inside the nucleon and thus are quite intimately related to its structure. Jefferson Lab experiment 93-027 measured P l and Pt, the longitudinal and transverse recoil proton polarization, respectively, for the 1 H(e-vector,e'p-vector) reaction in the four-momentum transfer squared range of 0.5 to 3.5 GeV 2 , using the Hall A facility with two high resolution spectrometers and a Focal Plane Polarimeter. The ratio G Ep /G Mp is directly proportional to the ratio P t /P l . These data have unprecedented precision, and show for the first time that the Q 2 dependence of G Ep and G Mp is very different. (author)

Investigations of space charge effects in the cryogenic gas filled stopping cell for the FRS ion catcher

Energy Technology Data Exchange (ETDEWEB)

Heisse, Fabian [IKTP, TU Dresden (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung (Germany); Dickel, Timo; Plass, Wolfgang; Geissel, Hans; Scheidenberger, Christoph [II. Physikalisches Institut, JLU Giessen (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung (Germany); Reiter, Moritz Pascal; Rink, Ann-Kathrin [II. Physikalisches Institut, JLU Giessen (Germany); Zuber, Kai [IKTP, TU Dresden (Germany); Collaboration: FRS Ion Catcher-Collaboration

2015-07-01

At the FRS Ion Catcher experiment precision mass measurements of short lived projectile and fission fragments are performed. Therefore highly charged ions with relativistic energies need to be thermalized to kinetic energies of several eV. This process takes place in the cryogenic gas filled stopping cell (CSC). All stopping cells suffer at large ion rates under space charge effects, which lead to decreasing efficiencies and can also influence the extraction time. Thus the understanding of space charge effects is of greatest importance to make full use of the higher yields at future rare ion beam facilities like FAIR. For this purpose simulation with the software SIMION {sup registered} concerning space charge effects were done. In this presentation the calculated transport efficiency of the CSC for different intensities, electric fields and spill structures are discussed and compared with measured results. Furthermore an outlook and first results of the simulation for the new CSC for the Low-Energy Branch at FAIR are given.

The HERMES recoil photon-detector and nuclear p{sub t}-Broadening at HERMES

Energy Technology Data Exchange (ETDEWEB)

Haarlem, Y. van

2007-09-15

The first part of this work consists of hardware research and development done in order to construct and test a photon-detector as one of the three detectors of the HERMES recoil detector. The HERMES recoil detector consists of a target cell, a silicon-detector, a scintillating fiber tracker, and a photon-detector. All are inside a super-conducting magnet. The silicon detector uses energy deposition to determine the momentum of the particle because in its energy range the energy deposition is an unambiguous function of the momentum of the particle. The scintillating fiber tracker is located outside the beam-vacuum and is surrounded by the photon-detector. It consists of two barrels with layers of scintillating fibers. It detects particles by converting their energy deposition into light. It measures two space points of a charged particle and from the bending of the assigned track (in the magnetic field provided by the super-conducting magnet) a momentum measurement can be derived. The photon-detector is located between the scintillating fiber tracker and the magnet. It consists (from the inside out) of three layers of tungsten showering material followed by scintillating strips. The second part of this work is an analysis performed concerning the transverse momentum broadening of hadrons produced in deep-inelastic scattering on a nuclear target compared to a D target. (orig.)

Study of Nuclear Collisions of 86 MeV/a.m.u. $^{12}$C with Heavy Targets by Collection of the Heavy Recoil Nuclei

CERN Multimedia

2002-01-01

The aim of this experiment is twofold:\\\\ \\\\ Firstly to test the possibilities of collection of the heavy recoil nuclei with the device presented schematically on the figure. The recoil nuclei escaping from the irradiated target are first thermalised in a gas (N^2). One then takes advantage of their remaining charge to collect them with an electric field on the surface of a solid state detector. Tests already performed with other beams give absolute efficiency around 5\\%. The best conditions of collections with very energetic |1|2C have first to be tested. Secondly to get some insight into nuclear reaction mechanisms induced by 86~MeV/a.m.u. |1|2C using the possibilities of this recoil chamber. Two kinds of mechanisms should occur in these interactions. If the incident energy is damped (deep inelastic reaction, fusion), the heavy nucleus will be highly excited and the residual nuclei will lie along the @G^n/@G^p~=~1~line. For heavy nuclei this line is located at about 25~mass units from the stability line. If ...

Broadband light generation at ~1300 nm through spectrally recoiled solitons and dispersive waves

DEFF Research Database (Denmark)

Falk, Peter Andreas; Frosz, Michael Henoch; Bang, Ole

2008-01-01

We experimentally study the generation of broadband light at ~1300 nm from an 810 nm Ti:sapphire femtosecond pump laser. We use two photonic crystal fibers with a second infrared zero-dispersion wavelength (λZ2) and compare the efficiency of two schemes: in one fiber λZ2=1400 nm and the light...... at 1300 nm is composed of spectrally recoiled solitons; in the other fiber λZ2=1200 nm and the light at 1300 nm is composed of dispersive waves....

''LIFETIME'': a computer program for analyzing Doppler-shift recoil-distance nuclear lifetime data

International Nuclear Information System (INIS)

Wells, J.C.; Fewell, M.P.; Johnson, N.R.

1985-10-01

The program LIFETIME is designed to extract lifetimes of nuclear levels from Doppler-shift recoil-distance experiments by performing a least-square fit to the experimental data (shifted and unshifted photopeak intensities and branching ratios). Initial populations of levels and transition rates between levels are treated as variable parameters. In terms of these parameters the population of each level as a function of time is determined by the Bateman equations, and the shifted and unshifted intensities are calculated. 19 refs., 5 figs

Direct determination of recoil ion detection efficiency for coincidence time-of-flight studies of molecular fragmentation

International Nuclear Information System (INIS)

Ben-Itzhak, I.; Carnes, K.D.; Ginther, S.G.; Johnson, D.T.; Norris, P.J.; Weaver, O.L.

1993-01-01

Molecular fragmentation of diatomic and small polyatomic molecules caused by fast ion impact has been studied. The evaluation of the cross sections of the different fragmentation channels depends strongly on the recoil ion detection efficiency, ε r (single ions proportional to ε r , and ion pairs to ε 2 r , etc.). A method is suggested for the direct determination of this detection efficiency. This method is based on the fact that fast H + + CH 4 collisions produce C 2+ fragments only in coincidence with H + and H + 2 fragments, that is, there is a negligible number of C 2+ singles, if any. The measured yield of C 2+ singles is therefore due to events in which the H + m of the H + m + C 2+ ion pair was not detected and thus is proportional to 1 - ε r . Methane fragmentation caused by 1 MeV proton impact is used to evaluate directly the recoil ion detection efficiency and to demonstrate the method of deriving the cross sections of all breakup channels. (orig.)

On unfolding counting-rate spectra of recoil-proton neutron detectors

International Nuclear Information System (INIS)

Yeivin, Yehuda

1983-01-01

This note proposes a possible scheme for unfolding recoil-proton neutron detector data, in which at first the undistorted proton source spectrum is derived. The main argument in favour of this scheme is that, compared with the conventional scheme, it necessitates somewhat weaker assumptions with respect to the unknown spectrum above the detector's upper energy cutoff, and would therefore be more reliable. We also demonstrate a simple, elementary proof of the wall effect correction for spherical detectors, and, in order to gain insight of the potential merits of the proposed unfolding scheme, illustrate our main argument by considering a hypothetic linear range-energy relation, in which case complete unfolding becomes possible with no assumptions at all on the proton spectrum above the cutoff energy. (author)

Sustainable eye-catcher. Greenhouse complex Anthura in Bleiswijk, Netherlands; Duurzame blikvanger. Kassencomplex Anthura in Bleiswijk

Energy Technology Data Exchange (ETDEWEB)

Overeijnder, F. [Overeijnder Van den Dool, Capelle aan den IJssel (Netherlands); Snellens, N.C. [Priva, De Lier (Netherlands)

2011-06-15

The architecture is impressive and a true eye catcher. Anthura's greenhouse building complex seems futuristic, but also stems from the design of the impressive greenhouses of the Royal Botanic Gardens of Kew, in London and the distinguished orangeries of castles and palaces. At the same time, the complex is a beautiful and modern example of sustainable and innovative entrepreneurship in glasshouse horticulture. The new 'Hortus Anthura' offers a pleasant and healthy climate for both crops and employees, is a great addition to the surrounding area, saves the environment and the climate and provides higher quality products. [Dutch] De indrukwekkende architectuur is een regegrechte blikvanger. Het kassencomplex van Anthura in Bleiswijk doet futuristisch aan, maar grijpt ook terug op de vormgeving van indrukwekkende greenhouses in de Royal Botanic Gardens van Kew in Londen en de deftige oranjerieen van kastelen en paleizen. Tegelijk is het complex een fraai en actueel voorbeeld van duurzaam en innovatief ondernemen in de glastuinbouw. De nieuwe 'Hortus Anthura' biedt zowel de planten als de medewerkers een goed leefklimaat, is een aanwinst voor de omgeving, spaart milieu en klimaat en levert een kwalitatief beter product.

Ejection of fast recoil atoms from solids under ion bombardment (medium-energy ion scattering by solid surfaces: Pt. 3)

International Nuclear Information System (INIS)

Dodonoy, A.I.; Mashkova, E.S.; Molchanov, V.A.

1989-01-01

This paper is the third part of our review surface scattering. Part I, which was devoted to the scattering of ions by the surfaces of disordered solids, was published in 1972; Part II, concerning scattering by crystal surfaces, was published in 1974. Since the publication of these reviews the material contained in them has become obsolete in many respects. A more recent account of the status of the problem has been given in a number of studies, including the book by E.S. Mashkova and V.A. Molchanov, Medium-Energy Ion Scattering by Solid Surfaces (Atomizdat, Moscow, 1980), than extended version of which was published by North-Holland in 1985. We note, however, that at the time these reviews were written the study of fast recoil atoms had not been carried out systematically; the problem was studied only as a by-product of surface scattering and sputtering. For this reason, in the above-mentioned works and in other reviews the data relating to recoil atoms were considered only occasionally. In recent years there have appeared a number of works - theoretical, experimental and computer -specially devoted to the study of the ejection of recoil atoms under ion bombardment. A number of interesting effects, which are due to the crystal structure of the target, have been discovered. It therefore, appeared desirable to us to systematize the available material and to present it as Part III of our continuing review. (author)

Techniques for measuring the atomic recoil frequency using a grating-echo atom interferometer

Science.gov (United States)

Barrett, Brynle

I have developed three types of time-domain echo atom interferometer (AIs) that use either two or three standing-wave pulses in different configurations. Experiments approaching the transit time limit are achieved using samples of laser-cooled rubidium atoms with temperatures AI. This interferometer uses two standing-wave pulses applied at times t = 0 and t = T 21 to create a superposition of atomic momentum states differing by multiples of the two-photon momentum, ħq = 2 ħk where k is the optical wave number, that interfere in the vicinity of t = 2T 21. This interference or "echo" manifests itself as a density grating in the atomic sample, and is probed by applying a near-resonant traveling-wave "read-out" pulse and measuring the intensity of the coherent light Bragg-scattered in the backward direction. The scattered light from the grating is associated with a λ/2-periodic modulation produced by the interference of momentum states differing by ħq. Interfering states that differ by more than ħq—which produce higher-frequency spatial modulation within the sample—cannot be detected due to the nature of the Bragg scattering detection technique employed in the experiment. The intensity of the scattered light varies in a periodic manner as a function of the standing-wave pulse separation, T21. The fundamental frequency of this modulation is the two-photon atomic recoil frequency, ω q = ħq2/2M, where q = 2k and M is the mass of the atom (a rubidium isotope in this case). The recoil frequency, ω q, is related to the recoil energy, Eq = ħωq, which is the kinetic energy associated with the recoil of the atom after a coherent two-photon scattering process. By performing the experiment on a suitably long time scale ( T21 >> τq = π/ω q ˜32 μs), ωq can be measured precisely. Since ωq contains the ratio of Planck's constant to the mass of the atom, h/M, a precise measurement of ωq can be used as a strict test of quantum theories of the electromagnetic force

Analysis of a Compressible Fluid Soft Recoil (CFSR) Concept Applied to a 155 MM Howitzer

Science.gov (United States)

1979-03-01

Nitrile or Buna-N ( NBR ) rubber with ’ backup rings of nylotron. HITRILE NVLOTRON Piston seals An unresolved problem is that the coefficient of...fluid at atmospheric pressure Poisson’s ratio for Nitrile rubber dynamic coefficient of friction for rubber mass of recoiling parts weight of...Greene, tweed 5 Co. Palmetto catalog.) 43 [i^ - 0.50 = coefficient of friction (An approximate figure for rubber supplied by RIA Rubber

Some aspects of the use of proton recoil proportional counters for fast neutron personnel dosimeters

International Nuclear Information System (INIS)

Yule, T.J.; Bennett, E.F.

1984-01-01

Gas-filled proton recoil proportional counters have been used extensively for the measurement of neutron spectra in degraded fission-spectrum environments. Some considerations relating to the use of these counters for personnel dosimetry are here described. High sensitivity and good accuracy in the determination of dose-equivalent can be obtained if relatively high pressure hydrogen-filled proportional counters are used as the active element in a dosimeter system

Taking account of the recoil effect under a light particle scattering on two heavy particles

International Nuclear Information System (INIS)

Peresypkin, V.V.

1978-01-01

Proceeding from the Faddeev equations the derivation of the Bruekner formula describing a light particle scattering by a system of two fixed force centers is presented. Using the zero-range two-particle potential and assuming the ratio of the incident particle mass to the heavy particle mass to be a small perturbation parameter the correction to the Bruekner formula is obtained taking into account the heavy particle recoil

Development and evaluation of a collection apparatus for recoil products for study of the deexcitation process of "2"3"5"mU

International Nuclear Information System (INIS)

Shigekawa, Y.; Kasamatsu, Y.; Shinohara, A.

2016-01-01

The nucleus "2"3"5"mU is an isomer with extremely low excitation energy (76.8 eV) and decays dominantly through the internal conversion (IC) process. Because outer-shell electrons are involved in the IC process, the decay constant of "2"3"5"mU depends on its chemical environment. We plan to study the deexcitation process of "2"3"5"mU by measuring the energy spectra of IC electrons in addition to the decay constants for various chemical forms. In this paper, the preparation method of "2"3"5"mU samples from "2"3"9Pu by using alpha-recoil energy is reported. A Collection Apparatus for Recoil Products was fabricated, and then collection efficiencies under various conditions were determined by collecting "2"2"4Ra recoiling out of "2"2"8Th electrodeposited and precipitated sources. The pressure in the apparatus (vacuum or 1 atm of N_2 gas) affected the variations of the collection efficiencies depending on the negative voltage applied to the collector. The maximum values of the collection efficiencies were mainly affected by the thickness of the "2"2"8Th sources. From these results, the suitable conditions of the "2"3"9Pu sources for preparation of "2"3"5"mU were determined. In addition, dissolution efficiencies were determined by washing collected "2"2"4Ra with solutions. When "2"2"4Ra was collected in 1 atm of N_2 gas and dissolved with polar solutions such as water, the dissolution efficiencies were nearly 100%. The method of rapid dissolution of recoil products would be applicable to rapid preparation of short-lived "2"3"5"mU samples for various chemical forms.

Szilard-Chalmers cation recoil studies in zeolites X and Y

International Nuclear Information System (INIS)

Lai, P.P.; Rees, L.V.C.

1976-01-01

The Szilard-Chalmers recoil of the cations Rb + , Cs + , Ba 2+ , La 3+ , Co 2+ , Zn 2+ , Cu 2+ and Na + from the sodalite cage and hexagonal prism sites into the supercage sites of zeolites X and Y has been studied. This study is complementary to that described in Lai et al, JCS Faraday I; 72:181 (1976). It has been found that these cations recoil from the sodalite cage sites into the supercage sites with a probability of approximately 90% whereas the corresponding probability for these cations in the hexagonal prism sites (site I) is between 40 and 50% depending on the cation. It is thus possible to determine the preferences shown by these cations for these 'locked-in' sites as a function of temperature of calcination, Tsub(c), concentration and type of other cations contained in these sites. In these studies the cations present in the supercage sites before irradiation were usually NH 4 + but Ba 2+ , Ca 2+ and Na + have also been used. When Tsub(c) > 400 0 C, Rb + and Cs + began to populate site I. These ions populated this site in zeolite X at lower calcination temperatures than required for zeolite Y. When Tsub(c) was increased from 110 to 220 0 C the occupancy of site I by Ba 2+ was greatly enhanced and when Tsub(c) > 440 0 C Ba 2+ ions now occupied this site in preference to all other 'locked-in' sites. Barium exhibited a higher affinity for site I in zeolite X than in zeolite Y when Tsub(c) = 110 0 C. If dehydrated La-Y was assumed to have 5 La 3+ ions per u.c. in site I, the hydration of this material did not change the concentration of La 3+ in site I. Co 2+ , Zn 2+ and Cu 2+ ions all exhibited similar affinities for the 'locked-in' sites of zeolites X and Y. (author)

Calibration of Recoil-In-Vacuum attenuations from first principles: comparison with recent experimental data on Fe isotopes

International Nuclear Information System (INIS)

Stone, Nicholas James; Stone, Jirina Rikovska; Stuchbery, Andrew E.; Jonsson, Per

2015-01-01

Precession of aligned nuclear spin systems in ions recoiling from the target into vacuum (RIV) with consequent attenuation of angular distributions of emitted radiation is, in principle, a versatile method for measurement of g-factors of nuclear excited states of lifetimes in the pico-second range (Stone et al., Phys. Rev. Lett., 94, 192501, 2005 and Stuchbery and Stone, Phys. Rev. C, 76, 034307, 2007). Calibration of the observed attenuations has been achieved in favourable cases through comparison with measurements on states having previously known g-factors and lifetimes. The general lack of suitable states with known g-factors has limited application of the RIV method. This paper concerns the present status of efforts to describe the states of excited ions recoiling into vacuum in detail so that the average interaction can be estimated with useful precision from a-priori theory. The calculations use the GRASP2K package (Froese-Fischer et al. 1997 and Jonsson, Comp. Phys. Comm., 177, 597, 2007 & 184, 2197, 2013) to obtain, for each recoiling ion change state, the individual possible electronic states, their configurations, lifetimes and hyperfine interactions. It is assumed that all possible ionic states are produced, up to a chosen excitation energy. This energy is selected to approximate the energy at which all states have lifetimes far shorter than the nuclear state of interest. It is further assumed that the ionic state total electron angular momenta are randomly oriented in space. The first estimates of the average attenuation of emission distributions, as a function of the product g τ of the nuclear state g-factor and mean lifetime, used an averaged precession frequency obtained neglecting transitions between electronic states. Improved calculations, which include such transitions, are described

Dispersion in a thermal plasma including arbitrary degeneracy and quantum recoil.

Science.gov (United States)

Melrose, D B; Mushtaq, A

2010-11-01

The longitudinal response function for a thermal electron gas is calculated including two quantum effects exactly, degeneracy, and the quantum recoil. The Fermi-Dirac distribution is expanded in powers of a parameter that is small in the nondegenerate limit and the response function is evaluated in terms of the conventional plasma dispersion function to arbitrary order in this parameter. The infinite sum is performed in terms of polylogarithms in the long-wavelength and quasistatic limits, giving results that apply for arbitrary degeneracy. The results are applied to the dispersion relations for Langmuir waves and to screening, reproducing known results in the nondegenerate and completely degenerate limits, and generalizing them to arbitrary degeneracy.

An electrostatic plunger device and the analysis of recoil-distance spectra

International Nuclear Information System (INIS)

Marchie van Voorthuysen, E.H. du; Smith, Ph.B.

1975-01-01

In the electrostatic plunger apparatus, a large stopper foil is drawn towards the target electrostatically. The attracting field is controlled in a feedback loop by the capacity, so that the distance is stabilized during the measurement. Formulae for line-shape analysis of γ-ray spectra from recoil-distance lifetime measurements (RDM) are given. A measurement of the life-time of the 1759 keV level in 26 Al is reported yielding (3.4+-0.6)ps, in agreement with results from Doppler-shift attenuation, but in disagreement with other RDM results. In addition, accurate stopping-power measurements are reported for 2-9MeV alpha particles in Al, Ni, Cu, Au and Mylar. (Auth.)

Design of magnetic analysis system for magnetic proton recoil spectrometer

International Nuclear Information System (INIS)

Qi Jianmin; Jiang Shilun; Zhou Lin; Peng Taiping

2010-01-01

Magnetic proton recoil (MPR) spectrometer is a novel diagnostic instrument with high performance for measurements of the neutron spectra from inertial confinement fusion (ICF) experiments and high power fusion devices. The design of the magnetic analysis system, which is a key part of the compact MPR-type spectrometer, has been completed through two-dimensional beam transport simulations and three-dimensional particle transport simulation. The analysis of the system's parameters and performances was performed, as well as system designs based on preferential principles of energy resolution, detection efficiency, and count rate, respectively. The results indicate that the magnetic analysis system can achieve a detection efficiency of 10 -5 ∼ 10 -4 level at the resolution range of 1.5% to 3.0% and fulfill the design goals of the compact MPR spectrometer. (authors)

Recoil 18F chemistry. XI. High pressure investigation of 1,1-difluoroethane

International Nuclear Information System (INIS)

Manning, R.G.; Root, J.W.

1980-01-01

Nuclear recoil 18 F reactions in CH 3 CHF 2 have been investigated throughout the effective pressure range 0.3--190 atm. The principal reaction channel is F-to-HF abstraction for which the combined yield from quasithermal and energetic processes in the presence of 5 mole% H 2 S additive is 83.4% +- 0.2%. A reaction mechanism is proposed that involves the organic product forming channels F-for-F, F-for-αH, F-for-βH, F-for-CH 3 and F-for-CHF 2 . The results are compared with those reported for the 18 F+CH 3 CF 3 system

A possible in vivo generator 103Pd/103mRh-Recoil considerations

International Nuclear Information System (INIS)

Rooyen, Johann van; Szucs, Zoltan; Rijn Zeevaart, Jan

2008-01-01

The use of Auger emitters as potential radiopharmaceuticals is increasingly investigated. One such radionuclide of interest is 103m Rh. This can be produced from 103 Ru or from 103 Pd in an in vivo generator. A potential problem with this concept is the recoil of the 103m Rh out of the carrier molecule and even out of the target cell. In order to determine whether this would happen in the 103 Pd/ 103m Rh case calculations were done to prove that this does not happen. From theoretical considerations it seems that the 103 Pd/ 103m Rh in vivo generator system would be possible

Automation of experiments at Dubna Gas-Filled Recoil Separator

Science.gov (United States)

Tsyganov, Yu. S.

2016-01-01

Approaches to solving the problems of automation of basic processes in long-term experiments in heavy ion beams of the Dubna Gas-Filled Recoil Separator (DGFRS) facility are considered. Approaches in the field of spectrometry, both of rare α decays of superheavy nuclei and those for constructing monitoring systems to provide accident-free experiment running with highly radioactive targets and recording basic parameters of experiment, are described. The specific features of Double Side Silicon Strip Detectors (DSSSDs) are considered, special attention is paid to the role of boundary effects of neighboring p-n transitions in the "active correlations" method. An example of an off-beam experiment attempting to observe Zeno effect is briefly considered. Basic examples for nuclear reactions of complete fusion at 48Ca ion beams of U-400 cyclotron (LNR, JINR) are given. A scenario of development of the "active correlations" method for the case of very high intensity beams of heavy ions at promising accelerators of LNR, JINR, is presented.

Development of bubble chambers with enhanced stability and sensitivity to low-energy nuclear recoils

International Nuclear Information System (INIS)

Bolte, W.J.; Collar, J.I.; Crisler, M.; Hall, J.; Holmgren, D.; Nakazawa, D.; Odom, B.; O'Sullivan, K.; Plunkett, R.; Ramberg, E.; Raskin, A.; Sonnenschein, A.; Vieira, J.D.

2007-01-01

The viability of using Bubble Chambers as dark matter particle detectors is considered. Techniques leading to the enhanced chamber stability needed for this new application are described in detail. Prototype trials show that sensitivity to the low-energy nuclear recoils induced by Weakly Interacting Massive Particles (WIMP) is possible in conditions of extreme insensitivity to minimum ionizing backgrounds. An understanding of detector response is demonstrated using existing theoretical models. We briefly comment on the prospects for detection of supersymmetric dark matter with large CF 3 I chambers

Detailed evaluation of two phase natural circulation flow in the cooling channel of the ex-vessel core catcher for EU-APR1400

Energy Technology Data Exchange (ETDEWEB)

Park, Rae-Joon, E-mail: rjpark@kaeri.re.kr; Ha, Kwang-Soon; Rhee, Bo-Wook; Kim, Hwan Yeol

2016-03-15

Highlights: • Ex-vessel core catcher of PECS is installed in EU-APR1400. • CE-PECS has been conducted to test a cooling capability of the PECS. • Two phase flow in CE-PECS and PECS was analyzed using RELAP5/MOD3. • RELAP5 results are very similar to the CE-PECS data. • The super-step design is suitable for steam injection into the downcomer in PECS. - Abstract: The ex-vessel core catcher of the PECS (Passive Ex-vessel corium retaining and Cooling System) is installed to retain and cool down the corium in the reactor cavity of the EU (European Union)-APR (Advanced Power Reactor) 1400. A verification experiment on the cooling capability of the PECS has been conducted in the CE (Cooling Experiment)-PECS. Simulations of a two-phase natural circulation flow using the RELAP5/MOD3 computer code in the CE-PECS and PECS have been conducted to predict the two-phase flow characteristics, to determine the natural circulation mass flow rate in the cooling channel, and to evaluate the scaling in the experimental design of the CE-PECS. Particularly from a comparative study of the prototype PECS and the scaled test facility of the CE-PECS, the orifice loss coefficient in the CE-PECS was found to be 6 to maintain the coolant circulation mass flux, which is approximately 273.1 kg/m{sup 2} s. The RELAP5 results on the coolant circulation mass flow rate are very similar to the CE-PECS experimental results. An increase in the coolant injection temperature and the heat flux lead to an increase in the coolant circulation mass flow rate. In the base case simulation, a lot of vapor was injected into the downcomer, which leads to an instability of the two-phase natural circulation flow. A super-step design at a downcomer inlet is suitable to prevent vapor injection into the downcomer piping.

Detailed evaluation of two phase natural circulation flow in the cooling channel of the ex-vessel core catcher for EU-APR1400

International Nuclear Information System (INIS)

Park, Rae-Joon; Ha, Kwang-Soon; Rhee, Bo-Wook; Kim, Hwan Yeol

2016-01-01

Highlights: • Ex-vessel core catcher of PECS is installed in EU-APR1400. • CE-PECS has been conducted to test a cooling capability of the PECS. • Two phase flow in CE-PECS and PECS was analyzed using RELAP5/MOD3. • RELAP5 results are very similar to the CE-PECS data. • The super-step design is suitable for steam injection into the downcomer in PECS. - Abstract: The ex-vessel core catcher of the PECS (Passive Ex-vessel corium retaining and Cooling System) is installed to retain and cool down the corium in the reactor cavity of the EU (European Union)-APR (Advanced Power Reactor) 1400. A verification experiment on the cooling capability of the PECS has been conducted in the CE (Cooling Experiment)-PECS. Simulations of a two-phase natural circulation flow using the RELAP5/MOD3 computer code in the CE-PECS and PECS have been conducted to predict the two-phase flow characteristics, to determine the natural circulation mass flow rate in the cooling channel, and to evaluate the scaling in the experimental design of the CE-PECS. Particularly from a comparative study of the prototype PECS and the scaled test facility of the CE-PECS, the orifice loss coefficient in the CE-PECS was found to be 6 to maintain the coolant circulation mass flux, which is approximately 273.1 kg/m"2 s. The RELAP5 results on the coolant circulation mass flow rate are very similar to the CE-PECS experimental results. An increase in the coolant injection temperature and the heat flux lead to an increase in the coolant circulation mass flow rate. In the base case simulation, a lot of vapor was injected into the downcomer, which leads to an instability of the two-phase natural circulation flow. A super-step design at a downcomer inlet is suitable to prevent vapor injection into the downcomer piping.

Reactions of recoil tritium generated by the 3He(n,p)3H reaction with aromatic compounds -intramolecular tritium distribution and radiochemical yield

International Nuclear Information System (INIS)

Nogawa, N.; Morikawa, Naotake; Oohashi, Kunio; Matuoka, H.; Moki, T.; Moriya, T.

1986-01-01

Reactions of recoil tritium with benzoic acid, acetanilide and β-phenethyl alcohol were studied using the 3 He(=n,p) 3 H reaction. The tritium distribution in the aromatic ring is approximately uniform in all the irradiated compounds and the tritium activity per C-H bond in the methyl and ethylene groups is 7 to 8 relative to that of the corresponding ring as standard. These findings are substantially the same as those obtained previously by the 6 Li(n,α) 3 H reactions, suggesting the same mechanism of tritiation for both recoil reactions. The tritiated parent compounds were obtained in high radiochemical yields: 45% for benzoic acid, 30% for acetanilide, 12% for β-phenethyl alcohol. (author)

Bio-mechanical assessment toward throwing and lifting process of i-LOCA (Innovative Lobster Catcher)

Science.gov (United States)

Sudiarno, A.; Dewi, D. S.; Putri, M. A.

2018-04-01

Indonesia is the country rich in marine resource, one of which is lobster. East java, one of Indonesian province, especially in Region of Gresik and Lamogan, has very huge potential of lobster. Current condition shown that lobster catch by the fisherman mostly depend on lucky factor, which the lobster unintentionally trapped in fisherman’s fish net. By using this mechanism, the number of lobster catch cannot be optimum. Previous researches have produced two versions of i-LOCA, Innovative Lobster Catcher, a special tool for catching the lobster. Although produce more lobster catch, second version of i-LOCA still needs to be scrutinized, one of that is bio-mechanical assessment. The second version of i-LOCA still has no tool to ease throwing and lifting it into the sea. This condition cause Musculoskeletal Disorder (MSD) toward the fisherman. This research perform bio-mechanical assessment toward throwing and lifting process in order to suggest improvement for i-LOCA as the third version. Based on body moment calculation, we found that throwing and lifting process of third version of i-LOCA, each was 3 times and 2 times better than second version of i-LOCA. Meanwhile, Rapid Entire Body Assessment (REBA) score of throwing and lifting process for third version of i-LOCA can be reduced by 5 points compared to second version of i-LOCA.

Comparison of in vivo acute stent recoil between the bioabsorbable everolimus-eluting coronary stent and the everolimus-eluting cobalt chromium coronary stent: insights from the ABSORB and SPIRIT trials

DEFF Research Database (Denmark)

Tanimoto, Shuzou; Serruys, Patrick W; Thuesen, Leif

2007-01-01

OBJECTIVES: This study sought to evaluate and compare in vivo acute stent recoil of a novel bioabsorbable stent and a metallic stent. BACKGROUND: The bioabsorbable everolimus-eluting coronary stent (BVS) is composed of a poly-L-lactic acid backbone, coated with a bioabsorbable polymer containing...... the antiproliferative drug, everolimus, and expected to be totally metabolized and absorbed in the human body. Because the BVS is made from polymer, it may have more acute recoil than metallic stents in vivo. METHODS: A total of 54 patients, who underwent elective stent implantation for single de novo native coronary...... artery lesions, were enrolled: 27 patients treated with the BVS and 27 patients treated with the everolimus-eluting cobalt chromium stent (EES). Acute absolute recoil, assessed by quantitative coronary angiography, was defined as the difference between mean diameter of the last inflated balloon...

Laser cooling of 85Rb atoms to the recoil-temperature limit

Science.gov (United States)

Huang, Chang; Kuan, Pei-Chen; Lan, Shau-Yu

2018-02-01

We demonstrate the laser cooling of 85Rb atoms in a two-dimensional optical lattice. We follow the two-step degenerate Raman sideband cooling scheme [Kerman et al., Phys. Rev. Lett. 84, 439 (2000), 10.1103/PhysRevLett.84.439], where a fast cooling of atoms to an auxiliary state is followed by a slow cooling to a dark state. This method has the advantage of independent control of the heating rate and cooling rate from the optical pumping beam. We operate the lattice at a Lamb-Dicke parameter η =0.45 and show the cooling of spin-polarized 85Rb atoms to the recoil temperature in both dimensions within 2.4 ms with the aid of adiabatic cooling.

Simulant melt experiments on performance of the in-vessel core catcher

International Nuclear Information System (INIS)

Kang, Kyoung-Ho; Park, Rae-Joon; Kim, Sang-Baik; Suh, K.Y.; Cheung, F.B.; Rempe, J.L.

2007-01-01

In order to enhance the feasibility of in-vessel retention (IVR) of molten core material during a severe accident for high-power reactors, an in-vessel core catcher (IVCC) was designed and evaluated as part of a joint United States-Korean International Nuclear Energy Research Initiative (INERI). The proposed IVCC is expected to increase the thermal margin for success of IVR by providing an 'engineered gap' for heat transfer from materials that relocate during a severe accident and potentially serving as a sacrificial material under a severe accident. In this study, LAVA-GAP experiments were performed to investigate the thermal and mechanical performance of the IVCC using the alumina melt as simulant. The LAVA-GAP experiments aim to examine the feasibility and sustainability of the IVCC under the various test conditions using 1/8th scale hemispherical test sections. As a feasibility test of the proposed IVCC in this INERI project, the effects of IVCC base steel materials, internal coating materials, and gap size between the IVCC and the vessel lower head were examined. The test results indicated that the internally coated IVCC has high thermal performance compared with the uncoated IVCC. In terms of integrity of the base steel, carbon steel is superior to stainless steel and the effect of bond coat is found to be trivial for the tests performed in this study. The thermal load is mitigated via boiling heat removal in the gap between the IVCC and the vessel lower head. The current test results imply that gaps less than 10 mm are not enough to guarantee effective cooling induced by water ingression and steam venting there through. Selection of endurable material and pertinent gap size is needed to implement the proposed IVCC concept into advanced reactor designs

Dispersion in thermal plasma including arbitrary degeneracy and quantum recoil

International Nuclear Information System (INIS)

Mushtaq, A.; Melrose, D.B.

2012-01-01

The longitudinal response function for a thermal electron gas was calculated including two quantum effects exactly, degeneracy and the quantum recoil. The Fermi-Dirac distribution was expanded in powers of a parameter that is small in the non-degenerate limit and the response function was evaluated in terms of the conventional plasma dispersion function to arbitrary order in this parameter. The infinite sum was performed in terms of poly logarithms in the long-wavelength and quasi-static limits, giving results that apply for arbitrary degeneracy. The results were applied to the dispersion relations for Langmuir waves and to screening, reproducing known results in the non-degenerate and completely degenerate limits], and generalizing them to arbitrary degeneracy. The occupation number for the completely degenerate limit is shown. The importance of the results regarding to semiconductor plasmas were highlighted. (orig./A.B.)

Multiple scattering effects in depth resolution of elastic recoil detection

International Nuclear Information System (INIS)

Wielunski, L.S.; Harding, G.L.

1998-01-01

Elastic Recoil Detection (ERD) is used to profile hydrogen and other low mass elements in thin films at surface and interfaces in a similar way that Rutherford Backscattering Spectroscopy (RBS) is used to detect and profile heavy elements. It is often assumed that the depth resolutions of these two techniques are similar. However, in contrast to typical RBS, the depth resolution of ERD is limited substantially by multiple scattering. In experimental data analysis and/or spectra simulations of a typical RBS measurement multiple scattering effects are often ignored. Computer programs used in IBA, such as RUMP, HYPRA or RBX do not include multiple scattering effects at all. In this paper, using practical thin metal structures with films containing intentionally introduced hydrogen, we demonstrate experimental ERD depth resolution and sensitivity limitations. The effects of sample material and scattering angle are also discussed. (authors)

Dual magnetic separator for TRIμP

International Nuclear Information System (INIS)

Berg, G.P.A.; Dermois, O.C.; Dammalapati, U.; Dendooven, P.; Harakeh, M.N.; Jungmann, K.; Onderwater, C.J.G.; Rogachevskiy, A.; Sohani, M.; Traykov, E.; Willmann, L.; Wilschut, H.W.

2006-01-01

The TRIμP facility, under construction at KVI, requires the production and separation of short-lived and rare isotopes. Direct reactions, fragmentation and fusion-evaporation reactions in normal and inverse kinematics are foreseen to produce nuclides of interest with a variety of heavy-ion beams from the superconducting cyclotron AGOR. For this purpose, we have designed, constructed and commissioned a versatile magnetic separator that allows efficient injection into an ion catcher, i.e., gas-filled stopper/cooler or thermal ionizer, from which a low energy radioactive beam will be extracted. The separator performance was tested with the production and clean separation of 21 Na ions, where a beam purity of 99.5% could be achieved. For fusion-evaporation products, some of the features of its operation as a gas-filled recoil separator were tested

Consistent empirical physical formula construction for recoil energy distribution in HPGe detectors by using artificial neural networks

International Nuclear Information System (INIS)

Akkoyun, Serkan; Yildiz, Nihat

2012-01-01

The gamma-ray tracking technique is a highly efficient detection method in experimental nuclear structure physics. On the basis of this method, two gamma-ray tracking arrays, AGATA in Europe and GRETA in the USA, are currently being tested. The interactions of neutrons in these detectors lead to an unwanted background in the gamma-ray spectra. Thus, the interaction points of neutrons in these detectors have to be determined in the gamma-ray tracking process in order to improve photo-peak efficiencies and peak-to-total ratios of the gamma-ray peaks. In this paper, the recoil energy distributions of germanium nuclei due to inelastic scatterings of 1–5 MeV neutrons were first obtained by simulation experiments. Secondly, as a novel approach, for these highly nonlinear detector responses of recoiling germanium nuclei, consistent empirical physical formulas (EPFs) were constructed by appropriate feedforward neural networks (LFNNs). The LFNN-EPFs are of explicit mathematical functional form. Therefore, the LFNN-EPFs can be used to derive further physical functions which could be potentially relevant for the determination of neutron interactions in gamma-ray tracking process.

Recoil proton polarization of neutral pion photoproduction from proton in the energy range between 400 MeV and 1142 MeV

International Nuclear Information System (INIS)

Kato, S.; Miyachi, T.; Sugano, K.; Toshioka, K.; Ukai, K.

1979-08-01

The recoil proton polarization of the reaction γp → π 0 p were measured at a C.M. angle of 100 0 for incident photon energies between 451 and 1106 MeV, and at an angle of 130 0 for energies from 400 MeV to 1142 MeV. One photon decayed from a π 0 -meson and a recoil proton were detected in coincidence. Two kinds of polarization scatterers were employed. In the range of proton kinetic energy less than 420 MeV and higher than 346 MeV, carbon plates and liquid hydrogen were used for determining the polarization. Results are compared with recent phenomenological analyses. From the Comparison between the present data and the asymmetry data given by the polarized target, the contribution of the invariant amplitudes A 3 can be estimated to be small at 100 0 . (author)

A G/NARRLI Effort. Measuring the Ionization Yield of Low-Energy Nuclear Recoils in Liquid Argon

Energy Technology Data Exchange (ETDEWEB)

Joshi, Tenzing Henry Yatish [Univ. of California, Berkeley, CA (United States)

2014-01-01

Liquid argon has long been used for particle detection due to its attractive drift properties, ample abundance, and reasonable density. The response of liquid argon to lowenergy O(10² -10⁴4 eV) interactions is, however, largely unexplored. Weakly interacting massive particles such as neutrinos and hypothetical dark-matter particles (WIMPs) are predicted to coherently scatter on atomic nuclei, leaving only an isolated low-energy nuclear recoil as evidence. The response of liquid argon to low-energy nuclear recoils must be studied to determine the sensitivity of liquid argon based detectors to these unobserved interactions. Detectors sensitive to coherent neutrino-nucleus scattering may be used to monitor nuclear reactors from a distance, to detect neutrinos from supernova, and to test the predicted behavior of neutrinos. Additionally, direct detection of hypothetical weakly interacting dark matter would be a large step toward understanding the substance that accounts for nearly 27% of the universe. In this dissertation I discuss a small dual-phase (liquid-gas) argon proportional scintillation counter built to study the low-energy regime and several novel calibration and characterization techniques developed to study the response of liquid argon to low-energy O(10² -10⁴ eV) interactions.

Recoil chemistry and solid state exchange in cobalt complexes : a new model

International Nuclear Information System (INIS)

Ramshesh, V.

1981-01-01

During the last thirty years considerable work has been done on various aspects of recoil chemistry and solid state exchange in cobalt complexes. Several interesting features such as 'oxygen effect', 'water of hydration effect', 'dilution with isomorphous materials', etc., have been observed. These data led workers to reject the older hypothesis based on 'fragmentation' and 'recombination' and suggest models based on exciton or electron induced exchange. However some recent data show that perhaps both the processes viz., thermal annealing in n-irradiated systems and solid state exchange are not bulk processes. This has led the author to propose a new model. In this model greater emphasis is placed on dissociation reactions followed by recombination and/or exchange reactions. (author)

Recoil-ion fractions in collisions of keV Ar sup + and Kr sup + ions with clean and adsorbate covered GaAs(1 1 0) surfaces

CERN Document Server

Gayone, J E; Grizzi, O; Vergara, L I; Passeggi, M C G; Vidal, R; Ferron, J

2002-01-01

Ion scattering and recoiling spectroscopy with time of flight analysis is used to study the ion fractions of Ga and As atoms recoiled in collisions of 5 keV Ar sup + and Kr sup + with clean GaAs(1 1 0) and with GaAs(1 1 0) covered with H, alkali metals (K and Cs) and fluorides (AlF sub 3). For the case of the clean surface, the Ga ion fraction is positive, large (approx 50%) and independent of the projectile type. The As ion fraction is also positive, low for Ar sup + (<10%) and relatively large (25%) for Kr sup + projectiles. The adsorption of H produces slight changes in both the As and Ga ion fractions, which is in agreement with the adsorption model where H reacts with both As and Ga atoms. The adsorption of alkalis produces strong changes in the ion fractions. At the beginning of the alkali adsorption the neutralization of Ga recoils increases fast with the coverage and follows approximately the variation of the work function. At coverages above half of the saturation value, where the work function ha...

Fried-Yennie gauge recalculation of the electron line induced radiative-recoil corrections to muonium hyperfine splitting

International Nuclear Information System (INIS)

Brook, V.Yu.; Eides, M.I.; Karshenboim, S.G.; Shelyuto, V.A.

1989-01-01

A new analytic calculation of radiative-recoil corrections to muonium ground-state hyperfine splitting induced by electron line insertions is performed. The starting point of this calculation is presented by the Fried-Yennie gauge expression for the electron line factor. The final result confirms the one obtained previously from the apparently different expression in the Feynman gauge and removes the slight discrepancy which existed in the literature between the calculations in different gauges. (orig.)

Annealing behavior of alpha recoil tracks in phlogopite

International Nuclear Information System (INIS)

Gao Shaokai; Yuan Wanming; Dong Jinquan; Bao Zengkuan

2005-01-01

Alpha recoil tracks (ARTs) formed during the a-decay of U, Th as well as their daughter nuclei are used as a new dating method which is to some extent a complementarity of fission track dating due to its ability to determine the age of young mineral. ARTs can be observable under phase-contrast interference microscope through chemical etching. In order to study the annealing behavior of ARTs in phlogopite, two methods of annealing experiments were executed. Samples were annealed in the electronic tube furnace at different temperatures ranging from 250 degree C to 450 degree C in steps of 50 degree C. For any given annealing temperature, different annealing times were used until total track fading were achieved. It is found that ARTs anneal much more easily than fission tracks, the annealing ratio increase non-linearly with annealing time and temperature. Using the Arrhenius plot, an activation energy of 0.68ev is finally found for 100% removal of ARTs, which is less than the corresponding value for fission tracks (FTs). Through extending the annealing time to geological time, a much lower temperature range of the sample's cooling history can be got.

Multiple scattering effects in depth resolution of elastic recoil detection

Energy Technology Data Exchange (ETDEWEB)

Wielunski, L.S.; Harding, G.L. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), Lindfield, NSW (Australia). Telecommunications and Industrial Physics; Szilagyi, E. [KFKI Research Institute for Particle and Nuclear Physics, Budapest, (Hungary)

1998-06-01

Elastic Recoil Detection (ERD) is used to profile hydrogen and other low mass elements in thin films at surface and interfaces in a similar way that Rutherford Backscattering Spectroscopy (RBS) is used to detect and profile heavy elements. It is often assumed that the depth resolutions of these two techniques are similar. However, in contrast to typical RBS, the depth resolution of ERD is limited substantially by multiple scattering. In experimental data analysis and/or spectra simulations of a typical RBS measurement multiple scattering effects are often ignored. Computer programs used in IBA, such as RUMP, HYPRA or RBX do not include multiple scattering effects at all. In this paper, using practical thin metal structures with films containing intentionally introduced hydrogen, we demonstrate experimental ERD depth resolution and sensitivity limitations. The effects of sample material and scattering angle are also discussed. (authors). 19 refs., 4 figs.

Differential cross section and recoil polarization measurements for the gamma p to K+ Lambda reaction using CLAS at Jefferson Lab

Energy Technology Data Exchange (ETDEWEB)

McCracken, Michael E. [Carnegie Mellon Univ., Pittsburgh, PA (United States)

2010-02-01

We present measurements of the differential cross section and Lambda recoil polarization for the gamma p to K+ Lambda reaction made using the CLAS detector at Jefferson Lab. These measurements cover the center-of-mass energy range from 1.62 to 2.84 GeV and a wide range of center-of-mass K+ production angles. Independent analyses were performed using the K+ p pi- and K+ p (missing pi -) final-state topologies; results from these analyses were found to exhibit good agreement. These differential cross section measurements show excellent agreement with previous CLAS and LEPS results and offer increased precision and a 300 MeV increase in energy coverage. The recoil polarization data agree well with previous results and offer a large increase in precision and a 500 MeV extension in energy range. The increased center-of-mass energy range that these data represent will allow for independent study of non-resonant K+ Lambda photoproduction mechanisms at all production angles.

Computer simulation of high-energy recoils in FCC metals: cascade shapes and sizes

International Nuclear Information System (INIS)

Heinisch, H.L.

1981-01-01

Displacement cascades in copper generated by primary knock-on atoms with energies from 1 keV to 500 keV were produced with the computer code MARLOWE. The sizes and other features of the point defect distributions were measured as a function of energy. In the energy range from 30 keV to 50 keV there is a transition from compact single damage regions to chains of generally closely-spaced, but distinct multiple damage regions. The average spacing between multiple damage regions remains constant with energy. Only a small fraction of the recoils from fusion neutrons is expected to produce widely separated subcascades

Studies of (p, γ) reactions with the Daresbury Recoil Separator at ORNL'S HRIBF

International Nuclear Information System (INIS)

Fitzgerald, R.; Abbotoy, E.; Bardayan, D.W.; Blackmon, J.C.; Champagne, A.E.; Chen, A.A.; Greife, U.; Hill, D.W.; James, A.N.; Kozub, R.L.; Lewis, T.A.; Livesay, R.; Ma, Z.; Mahan, S.L.; McConnell, J.W.; Milner, W.T.; Moazen, B.H.; Parker, P.D.; Pierce, D.E.; Roettger, M.E.; Sahin, L.; Shapira, D.; Smith, M.S.; Strieder, F.; Swartz, K.B.; Thomas, J.S.; Visser, D.W.

2005-01-01

The fusion of protons with radioactive nuclei is important in stellar explosions such as novae and X-ray bursts and for the production of neutrinos in the sun. The Daresbury Recoil Separator and a windowless gas target system have been installed at ORNL's Holifield Radioactive Ion Beam Facility (HRIBF) for measurements of proton capture reactions in inverse kinematics with radioactive ion beams. The performance of the system has been characterized with a number of experiments using stable ion beams. We report on results from these commissioning measurements and plans for measurements of the 1 H( 17 F, 18 Ne) and 1 H( 7 Be, 8 B) reactions

Rotator cuff tendon connections with the rotator cable.

Science.gov (United States)

Rahu, Madis; Kolts, Ivo; Põldoja, Elle; Kask, Kristo

2017-07-01

The literature currently contains no descriptions of the rotator cuff tendons, which also describes in relation to the presence and characteristics of the rotator cable (anatomically known as the ligamentum semicirculare humeri). The aim of the current study was to elucidate the detailed anatomy of the rotator cuff tendons in association with the rotator cable. Anatomic dissection was performed on 21 fresh-frozen shoulder specimens with an average age of 68 years. The rotator cuff tendons were dissected from each other and from the glenohumeral joint capsule, and the superior glenohumeral, coracohumeral, coracoglenoidal and semicircular (rotator cable) ligaments were dissected. Dissection was performed layer by layer and from the bursal side to the joint. All ligaments and tendons were dissected in fine detail. The rotator cable was found in all specimens. It was tightly connected to the supraspinatus (SSP) tendon, which was partly covered by the infraspinatus (ISP) tendon. The posterior insertion area of the rotator cable was located in the region between the middle and inferior facets of the greater tubercle of the humerus insertion areas for the teres minor (TM), and ISP tendons were also present and fibres from the SSP extended through the rotator cable to those areas. The connection between the rotator cable and rotator cuff tendons is tight and confirms the suspension bridge theory for rotator cuff tears in most areas between the SSP tendons and rotator cable. In its posterior insertion area, the rotator cable is a connecting structure between the TM, ISP and SSP tendons. These findings might explain why some patients with relatively large rotator cuff tears can maintain seamless shoulder function.

Experimental simulation of fragmentation and stratification of core debris on the core catcher of a fast breeder reactor

Energy Technology Data Exchange (ETDEWEB)

Pillai, Dipin S.; Vignesh, R. [Indian Institute of Technology, Chennai, Tamil Nadu (India); Sudha, A. Jasmin, E-mail: jasmin@igcar.gov.in [Safety Engineering Division, Reactor Design Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu (India); Pushpavanam, S.; Sundararajan, T. [Indian Institute of Technology, Chennai, Tamil Nadu (India); Nashine, B.K.; Selvaraj, P. [Safety Engineering Division, Reactor Design Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu (India)

2016-05-15

Highlights: • Fragmentation of two simultaneous metals jets in a bulk coolant analysed. • Particle size from experiments compared with theoretical analysis. • Jet breakup modes explained using dimensionless numbers. • Settling aspects of aluminium and lead debris on collector plate studied. • Results analysed in light of core debris settling on core catcher in a FBR. - Abstract: The complex and coupled phenomena of two simultaneous molten metal jets fragmenting inside a quiescent liquid pool and settling on a collector plate are experimentally analysed in the context of safety analysis of a fast breeder reactor (FBR) in the post accident heat removal phase. Following a hypothetical core melt down accident in a FBR, a major portion of molten nuclear fuel and clad/structural material which are collectively termed as ‘corium’ undergoes fragmentation in the bulk coolant sodium in the lower plenum of the reactor main vessel and settles on the core catcher plate. The coolability of this decay heat generating debris bed is dependent on the particle size distribution and its layering i.e., stratification. Experiments have been conducted with two immiscible molten metals of different densities poured inside a coolant medium to understand their fragmentation behaviour and to assess the possibility of formation of a stratified debris bed. Molten aluminium and lead have been used as simulants in place of molten stainless steel and nuclear fuel to facilitate easy handling. This paper summarizes the major findings from these experiments. The fragmentation of the two molten metals are explained in the light of relevant dimensionless numbers such as Reynolds number and Weber Number. The mass median diameter of the fragmented debris is predicted from nonlinear stability analysis of slender jets for lead jet and using Rayleigh's classical theory of jet breakup for aluminium jet. The agreement of the predicted values with the experimental results is good. These

High-resolution elastic recoil detection utilizing Bayesian probability theory

International Nuclear Information System (INIS)

Neumaier, P.; Dollinger, G.; Bergmaier, A.; Genchev, I.; Goergens, L.; Fischer, R.; Ronning, C.; Hofsaess, H.

2001-01-01

Elastic recoil detection (ERD) analysis is improved in view of depth resolution and the reliability of the measured spectra. Good statistics at even low ion fluences is obtained utilizing a large solid angle of 5 msr at the Munich Q3D magnetic spectrograph and using a 40 MeV 197 Au beam. In this way the elemental depth profiles are not essentially altered during analysis even if distributions with area densities below 1x10 14 atoms/cm 2 are measured. As the energy spread due to the angular acceptance is fully eliminated by ion-optical and numerical corrections, an accurate and reliable apparatus function is derived. It allows to deconvolute the measured spectra using the adaptive kernel method, a maximum entropy concept in the framework of Bayesian probability theory. In addition, the uncertainty of the reconstructed spectra is quantified. The concepts are demonstrated at 13 C depth profiles measured at ultra-thin films of tetrahedral amorphous carbon (ta-C). Depth scales of those profiles are given with an accuracy of 1.4x10 15 atoms/cm 2

Proton-recoil proportional-counter array for neutron-image construction

International Nuclear Information System (INIS)

Fink, C.L.; Eichholz, J.J.; DeVolpi, A.

1984-01-01

The fuel-motion measurement capability of the fast-neutron hodoscope has been upgraded by the addition of a 360-detector proton-recoil proportional-counter array, which detects high-energy fission neutrons. The current sensitive amplifier/discriminator module for each detector fits into a 12.7 by 12.7 by 102 mm package and cost less than $100 per module. It has a 50 ns rise time, a noise level of 100 nA, and a deadtime per event of 200 ns. Provision has been provided for the independent adjustment of the input current versus discriminator voltage for each module. The new proportional-counters cost approximately $400 each. Each detector has been tested to have the same gain versus voltage response. A space-charge model relating count-rate changes to space-charge effects has also been developed. The new detector array has been operational for approximately two years and has become the main detector system in fuel-motion analysis. It has significantly improved the linearity, stability, count-rate capability, and setup ease of the hodoscope

Cosmic ray-induced spallation recoil tracks in meteoritic phosphates: simulation at the CERN synchrocyclotron

Energy Technology Data Exchange (ETDEWEB)

Perron, C [Centre National de la Recherche Scientifique (CNRS), 75 - Paris (France). Inst. d` Astrophysique; [Museum National d` Histoire Naturelle, 75 - Paris (France)

1994-12-31

Annealed meteoritic phosphate crystals have been irradiated by 600 MeV protons to simulate cosmic ray irradiation in space. Spallation recoil tracks were then revealed, which mimic fission tracks, specially when observed in the SEM. A production yield of 9.3 {+-} 2.2 x 10{sup 8} spallation track per proton has been obtained for merrillite, and a substantially lower value (2.5 per proton) for apatite. A nominal production yield in space of 6 tracks per year has been derived, which may be used for a rough estimate of spallation track densities in chondritic merrillite. (Author).

Production of high specific activity 27Mg by fast neutron irradiation and recoil-aided leaching

International Nuclear Information System (INIS)

Wierczinski, B.; Goeij, J.J.M. de; Volkers, K.J.

2000-01-01

High specific activity 27 Mg was produced via recoil-aided leaching from alumina in aqueous medium during irradiation with fast neutrons from a nuclear reactor. After irradiation the aqueous medium was passed through an IC-chelate column, the 24 Na formed during irradiation was removed by elution with 0.25 ml . l -1 sodium acetate and subsequently the 27 Mg was eluted with 2 mol . l -1 hydrochloric acid. Irradiation of alumina with a particle size of 3 μm and a specific surface area of 100 m 2 . g -1 in Milli-Q Plus Water yielded 90% of the total 27 Mg activity produced. Under standard conditions activities of about 8 . 10 5 Bq and specific activities of ca. 10 13 Bq . mol -1 were obtained at the end of irradiation. The standard working conditions involved irradiation of 200 mg alumina dispersed in 0.5 ml liquid in a fast neutron flux of 3 . 10 15 m -2 . s -1 for 15 min, a waiting time of 10 min, and a processing time of 15 minutes. Various alumina samples with different particle sizes and specific surfaces were tested, and the 27 Mg yields were fitted to a mathematical function. Since the high leaching yields cannot only be explained by recoil only, other phenomena such as diffusion and leaching aided by the high hydration energy of the Mg 2+ ion are probably involved. (orig.)

Quality factor for charged particle recoils as a function of neutron energy

International Nuclear Information System (INIS)

Borak, T.B.; Stinchcomb, T.G.

1980-01-01

A method has been developed for computing the quality factor for any neutron spectrum with a maximum energy of 4 MeV. Calculated values for 41 adjacent neutron energy intervals from thermal to 4 MeV are tabulated. The table includes the fraction of absorbed dose and neutron dose equivalent produced by hydrogen recoils in soft tissue with the remaining fraction due to heavier particles. The production rate of 2.2 MeV photons from hydrogen capture in tissue is also given. The quality factor for a neutron spectrum of interest can be obtained from a weighted integration over the values listed. The total dose equivalent must include the contributions of absorbed dose from photons having a quality factor of unity. (author)

Moving towards first science with the St. George recoil separator

Science.gov (United States)

Meisel, Zachary; Berg, G. P. A.; Gilardy, G.; Moran, M.; Schmitt, J.; Seymour, C.; Stech, E.; Couder, M.

2015-10-01

The St. George recoil mass separator has recently been coupled to the 5MV St. Ana accelerator at the University of Notre Dame's Nuclear Science Lab. St. George is a unique tool designed to measure radiative alpha-capture reactions for nuclei up to A = 40 in inverse kinematics in order to directly obtain cross sections required for astrophysical models of stellar and explosive helium burning. Commissioning of St. George is presently taking place with primary beams of hydrogen, helium, and oxygen. In this presentation, results will be shown for the measured energy acceptance of St. George, which compare favorably to COSY results when employing the calculated optimal ion-optical settings. Additionally, future plans will be discussed, such as assessing the angular acceptance of St. George and the re-integration of HiPPO at the separator target position to provide a dense, windowless helium gas-jet target. The material presented in this work is partially supported by the National Science Foundation Grant No. 1419765.

Proton recoil spectra in spherical proportional counters calculated with finite element and Monte Carlo methods

Energy Technology Data Exchange (ETDEWEB)

Benmosbah, M. [Laboratoire de Chimie Physique et Rayonnement Alain Chambaudet, UMR CEA E4, Universite de Franche-Comte, 16 route de Gray, 25030 Besancon Cedex (France); Groetz, J.E. [Laboratoire de Chimie Physique et Rayonnement Alain Chambaudet, UMR CEA E4, Universite de Franche-Comte, 16 route de Gray, 25030 Besancon Cedex (France)], E-mail: jegroetz@univ-fcomte.fr; Crovisier, P. [Service de Protection contre les Rayonnements, CEA Valduc, 21120 Is/Tille (France); Asselineau, B. [Laboratoire de Metrologie et de Dosimetrie des Neutrons, IRSN, Cadarache BP3, 13115 St Paul-lez-Durance (France); Truffert, H.; Cadiou, A. [AREVA NC, Etablissement de la Hague, DQSSE/PR/E/D, 50444 Beaumont-Hague Cedex (France)

2008-08-11

Proton recoil spectra were calculated for various spherical proportional counters using Monte Carlo simulation combined with the finite element method. Electric field lines and strength were calculated by defining an appropriate mesh and solving the Laplace equation with the associated boundary conditions, taking into account the geometry of every counter. Thus, different regions were defined in the counter with various coefficients for the energy deposition in the Monte Carlo transport code MCNPX. Results from the calculations are in good agreement with measurements for three different gas pressures at various neutron energies.

Wave-driven Rotation in Supersonically Rotating Mirrors

Energy Technology Data Exchange (ETDEWEB)

A. Fetterman and N.J. Fisch

2010-02-15

Supersonic rotation in mirrors may be produced by radio frequency waves. The waves produce coupled diffusion in ion kinetic and potential energy. A population inversion along the diffusion path then produces rotation. Waves may be designed to exploit a natural kinetic energy source or may provide the rotation energy on their own. Centrifugal traps for fusion and isotope separation may benefit from this wave-driven rotation.

Wave-driven Rotation in Supersonically Rotating Mirrors

International Nuclear Information System (INIS)

Fetterman, A.; Fisch, N.J.

2010-01-01

Supersonic rotation in mirrors may be produced by radio frequency waves. The waves produce coupled diffusion in ion kinetic and potential energy. A population inversion along the diffusion path then produces rotation. Waves may be designed to exploit a natural kinetic energy source or may provide the rotation energy on their own. Centrifugal traps for fusion and isotope separation may benefit from this wave-driven rotation.

Some recoil corrections to the hydrogen hyperfine splitting

International Nuclear Information System (INIS)

Bodwin, G.T.; Yennie, D.R.

1988-01-01

We compute all of the recoil corrections to the ground-state hyperfine splitting in hydrogen, with the exception of the proton polarizability, that are required to achieve an accuracy of 1 ppm. Our approach includes a unified treatment of the corrections that would arise from a pointlike Dirac proton and the corrections that are due to the proton's non-QED structure. Our principal new results are a calculation of the relative order-α 2 (m/sub e//m/sub p/) contributions that arise from the proton's anomalous magnetic moment and a systematic treatment of the relative order-α(m/sub e//m/sub p/) contributions that arise from form-factor corrections. In the former calculation we introduce some new technical improvements and are able to evaluate all of the expressions analytically. In the latter calculation, which has been the subject of previous investigations by other authors, we express the form-factor corrections in terms of two-dimensional integrals that are convenient for numerical evaluation and present numerical results for the commonly used dipole parametrization of the form factors. Because we use a parametrization of the form factors that differs slightly from the ones used in previous work, our numerical results are shifted from older ones by a small amount

Radiation Recoil Effects on the Dynamical Evolution of Asteroids

Science.gov (United States)

Cotto-Figueroa, Desiree

The Yarkovsky effect is a radiation recoil force that results in a semimajor axis drift in the orbit that can cause Main Belt asteroids to be delivered to powerful resonances from which they could be transported to Earth-crossing orbits. This force depends on the spin state of the object, which is modified by the YORP effect, a variation of the Yarkovsky effect that results in a torque that changes the spin rate and the obliquity. Extensive analyses of the basic behavior of the YORP effect have been previously conducted in the context of the classical spin state evolution of rigid bodies (YORP cycle). However, the YORP effect has an extreme sensitivity to the topography of the asteroids and a minor change in the shape of an aggregate asteroid can stochastically change the YORP torques. Here we present the results of the first simulations that self-consistently model the YORP effect on the spin states of dynamically evolving aggregates. For these simulations we have developed several algorithms and combined them with two codes, TACO and pkdgrav. TACO is a thermophysical asteroid code that models the surface of an asteroid using a triangular facet representation and which can compute the YORP torques. The code pkdgrav is a cosmological N-body tree code modified to simulate the dynamical evolution of asteroids represented as aggregates of spheres using gravity and collisions. The continuous changes in the shape of an aggregate result in a different evolution of the YORP torques and therefore aggregates do not evolve through the YORP cycle as a rigid body would. Instead of having a spin evolution ruled by long periods of rotational acceleration and deceleration as predicted by the classical YORP cycle, the YORP effect is self-limiting and stochastic on aggregate asteroids. We provide a statistical description of the spin state evolution which lays out the foundation for new simulations of a coupled Yarkovsky/YORP evolution. Both self-limiting YORP and to a lesser

Rotating flow

CERN Document Server

Childs, Peter R N

2010-01-01

Rotating flow is critically important across a wide range of scientific, engineering and product applications, providing design and modeling capability for diverse products such as jet engines, pumps and vacuum cleaners, as well as geophysical flows. Developed over the course of 20 years' research into rotating fluids and associated heat transfer at the University of Sussex Thermo-Fluid Mechanics Research Centre (TFMRC), Rotating Flow is an indispensable reference and resource for all those working within the gas turbine and rotating machinery industries. Traditional fluid and flow dynamics titles offer the essential background but generally include very sparse coverage of rotating flows-which is where this book comes in. Beginning with an accessible introduction to rotating flow, recognized expert Peter Childs takes you through fundamental equations, vorticity and vortices, rotating disc flow, flow around rotating cylinders and flow in rotating cavities, with an introduction to atmospheric and oceanic circul...

Rotational seismology

Science.gov (United States)

Lee, William H K.

2016-01-01

Rotational seismology is an emerging study of all aspects of rotational motions induced by earthquakes, explosions, and ambient vibrations. It is of interest to several disciplines, including seismology, earthquake engineering, geodesy, and earth-based detection of Einstein’s gravitation waves.Rotational effects of seismic waves, together with rotations caused by soil–structure interaction, have been observed for centuries (e.g., rotated chimneys, monuments, and tombstones). Figure 1a shows the rotated monument to George Inglis observed after the 1897 Great Shillong earthquake. This monument had the form of an obelisk rising over 19 metres high from a 4 metre base. During the earthquake, the top part broke off and the remnant of some 6 metres rotated about 15° relative to the base. The study of rotational seismology began only recently when sensitive rotational sensors became available due to advances in aeronautical and astronomical instrumentations.

COMMENT ON THE BLACK HOLE RECOIL CANDIDATE QUASAR SDSS J092712.65+294344.0

International Nuclear Information System (INIS)

Shields, G. A.; Bonning, E. W.; Salviander, S.

2009-01-01

The Sloan Digital Sky Survey (SDSS) quasar J092712.65+294344.0 has been proposed as a candidate for a supermassive black hole (∼10 8.8 M sun ) ejected at high speed from the host galactic nucleus by gravitational radiation recoil, or alternatively for a supermassive black hole binary. This is based on a blueshift of 2650 km s -1 of the broad emission lines ('b-system') relative to the narrow emission lines ('r-system') presumed to reflect the galaxy velocity. New observations with the Hobby-Eberly Telescope (HET) confirm the essential features of the spectrum. We note a third redshift system, characterized by weak, narrow emission lines of [O III] and [O II] at an intermediate velocity 900 km s -1 redward of the broad-line velocity ('i-system'). A composite spectrum of SDSS QSOs similar to J0927+2943 illustrates the feasibility of detecting the calcium K absorption line in spectra of sufficient quality. The i-system may represent the QSO host galaxy or a companion. Photoionization requires the black hole to be ∼3 kpc from the r-system emitting gas, implying that we are observing the system only 10 6 yr after the recoil event and contributing to the low probability of observing such a system. The HET observations give an upper limit of 10 km s -1 per year on the rate of change of the velocity difference between the r- and b-systems, constraining the orbital phase in the binary model. These considerations and the presence of a cluster of galaxies apparently containing J0927+2943 favor the idea that this system represents a superposition of two active galactic nuclei.

Hydrogen determination using secondary processes of recoil proton interaction with sample material

International Nuclear Information System (INIS)

Muminov, V.A.; Khajdarov, R.A.; Navalikhin, L.V.; Pardaev, Eh.

1980-01-01

Possibilities of hydrogen content determination in different materials according to secondary processes of interaction of recoil protons(irradiation in the field of fast neutrons) with sample material resulting in the appearance of characteristic X-ray irradiation are studied. Excitated irradiation is recorded with a detector placed in the protective screen and located at a certain distance from the object analyzed and neutron source. The method is tested taking as an example analysis of bromine-containing samples (30% Br, 0.5% H) and tungsten dioxide. The determination limit of hydrogen content constitutes 0.05% at confidence coefficient of 0.9. Neutron flux constituted 10 3 neutrons/cm 2 xs, the time of measurement being 15-20 minutes, the distance from the sample to the detector being 12-15 cm [ru

Connection of a He-jet recoil transport system to an ion source

International Nuclear Information System (INIS)

Sheppard, G.A.

1977-02-01

In an effort to make non-gaseous fission products available for on-line separation and study with the TRISTAN facility, an investigation of the operational characteristics of a He-jet recoil transport system and a TRISTAN-type ion source was conducted after interfacing them with a skimmer. So that experimental results could be understood and controlled, studies of the dynamics of choked flow in a capillary and of the transport characteristics were made. Satisfactory performance of the He-jet system was obtained, but large temperature and pressure gradients thwarted early attempts to efficiently couple the He-jet to the ion source. The pressure-related difficulties have been overcome by employing a skimmer to remove extraneous gases before injection of the activities into the ion source, but efforts to conquer the temperature-related problems continue

Semileptonic weak and electromagnetic interactions in nuclei: recoil polarization in muon capture

International Nuclear Information System (INIS)

Rosenfelder, R.

1979-01-01

An analysis of the polarization of the recoiling nucleus following the capture of polarized muons by nuclei is performed. New general expressions for arbitrary nuclear spin are obtained in terms of the same reduced matrix elements which govern inelastic electron scattering and β-decay. As an application the A = 12 system is considered and uncertainties in the nuclear structure are studied by using different sets of one-body density matrices. With the canonical values of the weak form factors (i.e. absence of second-class currents) a fairly good agreement with the experimental data is achieved including the inelastic form factor at high momentum transfers and the recently measured average 12 B polarization. Implications of the new corrected value of the average polarization on weak form factors and nuclear structure are discussed. (Auth.)

Etching behaviour of alpha-recoil tracks in natural dark mica studied via artificial ion tracks

International Nuclear Information System (INIS)

Lang, M.; Glasmacher, U.A.; Neumann, R.; Wagner, G.A.

2003-01-01

Alpha-recoil tracks (ARTs) created by the α-decay of U, Th, and their daughter nuclei, are used by a new dating method to determine the formation age of dark mica bearing Quaternary and Neogene volcanic rocks and the cooling age of plutonic and metamorphic rocks [Chem. Geol. 166 (2000) 127, Science 155 (1967) 1103]. The age equation combines the volumetric density of ARTs with the U and Th contents. Etching latent ARTs (diameter 30-100 nm) in the mica mineral phlogopite by HF and measuring the areal density of triangular etch pits by optical and scanning force microscopy (SFM) leads to a linear growth of ART areal density versus etching time. The ART volume density is a function of the slope of the areal density and the etching rate (v eff ). Therefore, the determination of v eff is essential for the calculation of an age value. To determine the etching parameters such as etching efficiency and v eff , phlogopite samples were irradiated with 80 keV Au ions. Irradiated surfaces were etched with 4% HF at 23±2 deg. C during successive time intervals and after each interval studied with SFM. The etching rate v eff was determined by different techniques. To evaluate the threshold of etchability, the energy losses of the Au ions and α-recoil nuclei in phlogopite were calculated with the SRIM00 code. The etching efficiency of the Au ion tracks was then used to predict the corresponding etching efficiency of the natural radioactive nuclei

Dynamics and mechanisms of hot chemistry stimulated by recoil methods. Progress report, March 1, 1977--February 28, 1978

International Nuclear Information System (INIS)

Spicer, L.D.

1977-11-01

Evaluation of the nuclear recoil chemical activation process in cyclobutane-t and subsequent collisional energy transfer processes has shown: The average quanta of energy transferred from cyclobutane excited to vibrational energies near 100 kcal/mole upon collision is in the kcal/collision range, and also the hot tritium for hydrogen replacement reaction deposits about 46% of its kinetic energy into internal modes of the cyclobutane-t and the energy distribution of activated molecules is relatively independent of the composition of mixed bath systems. An evaluation of the average energy at which recoil stimulated, hot hydrogen replacement reaction in cyclohexane and n-butane occurs has been made as a function of added moderator. Calculated results indicate that the average reaction energy is relatively independent of composition over the range from 0 to 99% moderation with noble gases in well scavenged systems of moderate reactivity. Geometrical isomerization accompanying the gas phase chlorine atom replacement reaction in 2,3 dichlorohexafluoro-2-butene as a function of moderation has been investigated. Both a thermal or near thermal reaction path having a trans/cis product ratio of 1.3 and a high energy process which preferentially forms trans product from both cis and trans reactant are found

The Magnetic Recoil Spectrometer for time-resolved neutron measurements (MRSt) at the NIF

Science.gov (United States)

Parker, C. E.; Frenje, J. A.; Wink, C. W.; Gatu Johnson, M.; Lahmann, B.; Li, C. K.; Seguin, F. H.; Petrasso, R. D.; Hilsabeck, T. J.; Kilkenny, J. D.; Bionta, R.; Casey, D. T.; Khater, H. Y.; Forrest, C. J.; Glebov, V. Yu.; Sorce, C.; Hares, J. D.; Siegmund, O. H. W.

2017-10-01

The next-generation Magnetic Recoil Spectrometer, called MRSt, will provide time-resolved measurements of the DT-neutron spectrum. These measurements will provide critical information about the time evolution of the fuel assembly, hot-spot formation, and nuclear burn in Inertial Confinement Fusion (ICF) implosions at the National Ignition Facility (NIF). The neutron spectrum in the energy range 12-16 MeV will be measured with high accuracy ( 5%), unprecedented energy resolution ( 100 keV) and, for the first time ever, time resolution ( 20 ps). An overview of the physics motivation, conceptual design for meeting these performance requirements, and the status of the offline tests for critical components will be presented. This work was supported in part by the U.S. DOE, LLNL, and LLE.

Recoil distance measurements of litetimes of levels in 2120F and 16N

International Nuclear Information System (INIS)

Kozub, R.L.; Mateja, J.F.; Lin, J.; Lister, C.J.; Olness, J.; Warburton, E.K.; Bynum, M.R.; Matthews, T.L.

1981-01-01

The previously-reported measurements of meanlives of 20 21 F levels using the recoil-distance method (RDM) and 18 O + 7 Li reactions have been repeated using improved experimental techniques. In addition, the lifetimes of two 16 N levels were measured, using the same experimental setup and 11 B + 7 Li reactions. Data were taken using the BNL precision plunger, in which were mounted a stretched Ta stopper foil (approx. 20 /sub cm 2 //sup mg/ thick) and a 300 μg/cm 2 - thick Li target condensed onto a stretched, 1.4 mg/cm 2 - thick Ta backing. Changes in target-to-stopper distance (d) could be controlled to an accuracy of about +- 1 μm, and were monitored by measuring target-to-stopper capacitance

Global rotation

International Nuclear Information System (INIS)

Rosquist, K.

1980-01-01

Global rotation in cosmological models is defined on an observational basis. A theorem is proved saying that, for rigid motion, the global rotation is equal to the ordinary local vorticity. The global rotation is calculated in the space-time homogeneous class III models, with Godel's model as a special case. It is shown that, with the exception of Godel's model, the rotation in these models becomes infinite for finite affine parameter values. In some directions the rotation changes sign and becomes infinite in a direction opposite to the local vorticity. The points of infinite rotation are identified as conjugate points along the null geodesics. The physical interpretation of the infinite rotation is discussed, and a comparison with the behaviour of the area distance at conjugate points is given. (author)

Anion effect on the retention of recoil atom of coordination crystalline compounds

International Nuclear Information System (INIS)

Dimotakis, P.N.; Papadopoulos, B.P.

1980-01-01

The anion effect of various cobaltic crystalline compounds - having the same cation and differing in anion -on the retention of neutron activated central cobalt atom has been studied. The cation was trans-dichloro(bis)ethylenediamine cobalt(III) and the anions were simple spherical anions (Cl - , Br - , I - ), planar anions (NO 3 - ), trigonal pyramidal anions (ClO 3 - , BrO 3 - ), tetrahedral anions (SO 4 2- , CrO 4 2- , MnO 4 - ) and linear anions (SCN - ). The cobalt-60 activity after reactor irradiation either in simple Co 2+ cation or in cobaltic complex cation determined the retention values. In all irradiations at ordinary temperature and at liquid nitrogen temperature the results showed an effect of the different anions, depending on the geometry, volume and charge, on the recombination of the recoil cobalt with the ligands in the coordination sphere. (author)

Neutron scattering facility for the calibration of the response to nuclear recoils

International Nuclear Information System (INIS)

Jochum, J.; Feilitzsch, F. von; Huber, M.; Jagemann, T.; Lachenmaier, T.; Lanfranchi, J.-C.; Potzel, W.; Ruedig, A.; Schnagl, J.; Stark, M.; Wulandari, H.; Chambon, B.; Drain, D.; Gascon, J.; Jesus, M. de; Martineau, O.; Simon, E.; Stern, M.

2002-01-01

A possibility to search for elementary particles as dark matter candidates is to detect elastic scattering with cryogenic detectors. For the interpretation of the data one has to determine the detector response to nuclear recoils, the so-called quenching factors. They can differ for the heat-, for the scintillation- and for the ionization-signal and can be measured by scattering of neutrons. The CRESST- and the EDELWEISS-collaborations have set up a neutron scattering facility for cryogenic detectors at the tandem-accelerator of the Munich 'Maier-Leibniz-Labor.' The scattering angle and the time-of-flight of the neutrons are measured by an array of liquid scintillator cells. The pulsed high energy (11 MeV) neutron beam is created by nuclear reaction of a 11 B on a H 2 -gas target. The set-up and the results of first tests are presented

The Differential Cross Section and Λ Recoil Polarization from γδ -> Κ0(ρ)

Energy Technology Data Exchange (ETDEWEB)

Compton, Nicholas [Ohio Univ., Athens, OH (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

2017-04-30

Presented is the analysis of the differential cross section and Λ recoil polarization from the reaction γδ -> Κ0(ρ). This work measured these observables over beam energies from 0.90 GeV to 3.0 GeV. These measurements are the first in this channel to cover such a wide range of energies. The data were taken using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Laboratory (JLAB) along with a tagged photon beam. This analysis was completed by identifying events of interest that decayed into the final state topology of π-π+,π-&rho'(ρ). Through conservation of energy and momentum, the Κ0, Λ and missing mass of the spectator proton were reconstructed. Utilizing the same analysis techniques, the observables were measured on two different experiments with good agreement. Photoproduction of strange mesons from the neutron are difficult to measure, consequently there are only a few measurements of this kind. Despite that, these reactions supply essential complementary data to those on the proton. The differential cross sections and the recoil polarization extracted, span the region where new nucleon resonances have been found from studies of the reaction γρ -> Κ+Λ. Comparisons between the Κ+Λ and Κ0Λ cross section demonstrate that possible interference terms near 1900 MeV are less pronounced in the latter. This unexpected result inspired a partial wave analyses (PWA) to be fitted to the data. The fit solution shows that this measurement fostered an improvement on the knowledge of observed resonance parameters, necessary to understanding these excited states. The study of nucleon resonances is a key motivating factor since the resonance masses can be calculated from the theory of the strong nuclear force, called quantum chromodynamics, or QCD.

Polarization of recoil deuteron in ed elastic scattering at medium energies

International Nuclear Information System (INIS)

Bhalerao, R. S.

1981-12-01

Vector and tensor polarizations of the recoil deuteron in ed elastic scattering are calculated for THETA=0deg-180deg and q 2 2 . A longitudinally polarized electron beam is assumed to scatter off an unpolarized deuteron target. Calculations are made in the relativistic impulse approximation using a recently described approach based on the Bethe-Salpeter equation. Results are different, at high q 2 even qualitatively so, from those of a non-relativistic calculation, and a relativistic calculation which takes the spectator nucleon on-mass-shell. In the light of these results a recent suggestion that the polarization measurements would throw new light on the off-shell behavior and tensor force strength of the NN interaction are reexamined. Results are also presented for the three deuteron form factors Gsub(C), Gsub(Q), and Gsub(M), and the often-needed related quantities Ssub(S), Ssub(Q), and Ssub(M). The latter results may have an important implication in high-momentum transfer reactions involving deuteron. (author)

A saúde e os riscos dos pescadores e catadores de caranguejo da Baía de Guanabara The health and risks of fishermen and crab catchers of Guanabara Bay

Directory of Open Access Journals (Sweden)

Márcia Ferreira Mendes Rosa

2010-06-01

Full Text Available O artigo discute a saúde, os riscos e o trabalho dos pescadores e catadores de caranguejo da região da APA de Guapimirim na Baía de Guanabara. Eles são típicos trabalhadores informais, sem proteção e garantias trabalhistas. Estão expostos a vários riscos no seu dia a dia, como acidentes com embarcações, com os apetrechos de pesca, com o próprio pescado, afogamentos, além de estarem expostos à grande radiação e variações climáticas. Há ainda a sobrecarga de peso e trabalho e a própria atividade noturna que potencializa mais os riscos. A partir de uma amostra de cem trabalhadores, que relataram por meio de uma pesquisa exploratória e descritiva de abordagem quanti-qualitativa, traçou-se um perfil dos mesmos. São trabalhadores que possuem baixa escolaridade, predominando o primeiro grau incompleto (63% e com 12% do total de analfabetos. Uma parcela desses trabalhadores (44% relataram possuir doenças ou agravos à saúde. Essas doenças estão relacionadas à sobrecarga de peso, à grande jornada de trabalho e todas as situações de periculosidade a que estão expostos em suas atividades. Foram identificadas grandes dificuldades desses trabalhadores em realizar o seu labor, havendo a necessidade urgente de encontrar medidas que possam melhorar suas condições de trabalho e vida.The article discusses the health, risks and the work of fishermen and crab catchers in region of APA Guapimirim in Guanabara Bay. Fishermen and crab catchers are typical informal workers, they suffer from lack of protection and working guarantee. They are exposed to working risks day by day such as accidents with fishing boat, fishing equipment, the own fish, drowning, as well as a lot of radiation and climatic variation. There are still the weight and work overload, as well as the activities done at night that increase the potential risks. A sample of 100 fishermen and crab catchers had told by quantitative-qualitative research that it was possible

Mass spectroscopy of recoiled ions, secondary ion mass spectroscopy, and Auger electron spectroscopy investigation of Y2O3-stabilized ZrO2(100) and (110)

International Nuclear Information System (INIS)

Herman, G.S.; Henderson, M.A.; Starkweather, K.A.; McDaniel, E.P.

1999-01-01

We have studied the (100) and (110) surfaces of yttria-stabilized cubic ZrO 2 using Auger electron spectroscopy, low energy electron diffraction (LEED), direct recoil spectroscopy, mass spectroscopy of recoiled ions (MSRI), and secondary ion mass spectroscopy (SIMS). The concentration of yttrium at the surface was weakly influenced by the surface structure under the experimental conditions investigated. Both MSRI and SIMS indicated a more enhanced yttrium signal than zirconium signal at the surface compared to the respective bulk concentrations. The surfaces were not very well ordered as indicated by LEED. The yttria-stabilized cubic ZrO 2 single crystal surfaces may not be a suitable model material for pure phase ZrO 2 surfaces due to significant yttria concentrations at the surface. copyright 1999 American Vacuum Society

Recoil ion momentum spectroscopy in atomic and nuclear physics: applications to low energy ion-atom/molecule collisions and to beta-neutrino angular correlation in beta decay

International Nuclear Information System (INIS)

Flechard, X.

2012-12-01

Since the early 1990's, Recoil Ion Momentum Spectroscopy is an ideal tool for ion-atom and ion-molecule collisions study. We detail here the development of this experimental technique during the last twenty years, illustrated with some of the most striking results obtained at GANIL (Caen) and J.R. Mac Donald Laboratory (Kansas State University). Recoil Ion Momentum Spectroscopy is also particularly well suited for β-ν angular correlation measurements in nuclear β decay. The LPCTrap experiment, installed at GANIL, is based on this technique, coupled to the use of a Paul trap for the radioactive ions confinement. The precise measurements performed with this setup allow both, to test specific aspects of the Standard Model of elementary particles, and to study the electron shake-off process following β decay. (author)

Trapping of slow recoil ions: past results and speculations on the future

International Nuclear Information System (INIS)

Prior, M.H.

1983-01-01

A simple electrostatic ion trap has been utilized to capture low energy recoil ions made by fast heavy ion impact upon a neon gas target. The heavy ion beams have been provided by the LBL SuperHILAC and the work has so far concentrated upon studies of the decay of the trapped ion population in time following creation by the pulsed HILAC beam (3.3 msec pulse length, 36Hz repetition rate). The various charge states decay predominantly via electron capture collisions with the ambient gas in the ion trap. By varying the gas composition and density, one can determine the electron capture rate constants from which an effective (velocity averaged) capture cross-section can be obtained. The uniqueness of this work lies in the high charge states, up to Ne 10 + (fully stripped), and the low mean collision energies available (in the range 1.0 to 70.0 eV)

Investigation of incomplete fusion dynamics by measurement of excitation functions in the 20Ne + 59Co system

International Nuclear Information System (INIS)

Singh, D.; Linda, Sneha Bharti; Giri, Pankaj K.; Singh, Smita Shree; Kumar, Harish; Afzal Ansari, M.; Ali, Rahbar; Rashid, M.H.; Guin, R.; Das, S.K.

2015-01-01

In the present work, an attempt has been made to address some important aspects of CF and ICF dynamics for the system 20 Ne + 59 Co in the projectile energy range ≈ 62–150 MeV by using recoil catcher activation technique with the following off-line γ-ray spectroscopy. Excitation Functions (EFs) for the following reactions: 59 Co(Ne, α p4n) 70 Ga, 59 Co(Ne, 3αp3n) 63 Zn, 59 Co (Ne, 3αp4n) 62 Zn and 59 Co (Ne, 4α3n) 60 Cu have been measured. No precursor decay contribution has been observed for these measured evaporation residues. The measured values of total fusion cross-sections of the above evaporation residues have been compared with the theoretical total complete fusion cross sections calculated by code PACE-2, which do not take into account ICF contribution

Lower Extremity Muscle Activation and Kinematics of Catchers When Throwing Using Various Squatting and Throwing Postures

Directory of Open Access Journals (Sweden)

Yi-Chien Peng, Kuo-Cheng Lo, Lin-Hwa Wang

2015-09-01

Full Text Available This study investigated the differences in joint motions and muscle activities of the lower extremities involved in various squatting postures. The motion capture system with thirty-one reflective markers attached on participants was used for motion data collection. The electromyography system was applied over the quadriceps, biceps femoris, tibialis anterior, and gastrocnemius muscles of the pivot and stride leg. The joint extension and flexion in wide squatting are greater than in general squatting (p = 0.005. Knee joint extension and flexion in general squatting are significantly greater than in wide squatting (p = 0.001. The adduction and abduction of the hip joint in stride passing are significantly greater than in step squatting (p = 0.000. Furthermore, the adduction and abduction of the knee joint in stride passing are also significantly greater than in step squatting (p = 0.000. When stride passing is performed, the muscle activation of the hamstring of the pivot foot in general squatting is significantly greater than in wide squatting (p < 0.05, and this difference continues to the stride period. Most catchers use a general or wide squatting width, exclusive of a narrow one. Therefore, the training design for strengthening the lower extremity muscles should consider the appropriateness of the common squat width to enhance squat-up performance. For lower limb muscle activation, wide squatting requires more active gastrocnemius and tibialis anterior muscles. Baseball players should extend the knee angle of the pivot foot before catching the ball.

Performance of the Recoil Mass Spectrometer and its detector systems at the Holifield Radioactive Ion Beam Facility

International Nuclear Information System (INIS)

Gross, C.J.; Ginter, T.N.; Shapira, D.; Milner, W.T.; McConnell, J.W.; James, A.N.; Johnson, J.W.; Mas, J.; Mantica, P.F.; Auble, R.L.; Das, J.J.; Blankenship, J.L.; Hamilton, J.H.; Robinson, R.L.; Akovali, Y.A.; Baktash, C.; Batchelder, J.C.; Bingham, C.R.; Brinkman, M.J.; Carter, H.K.; Cunningham, R.A.; Davinson, T.; Fox, J.D.; Galindo-Uribarri, A.; Grzywacz, R.; Liang, J.F.; MacDonald, B.D.; MacKenzie, J.; Paul, S.D.; Piechaczek, A.; Radford, D.C.; Ramayya, A.V.; Reviol, W.; Rudolph, D.; Rykaczewski, K.; Toth, K.S.; Weintraub, W.; Williams, C.; Woods, P.J.; Yu, C.-H.; Zganjar, E.F.

2000-01-01

The recently commissioned Recoil Mass Spectrometer (RMS) at the Holifield Radioactive Ion Beam Facility (HRIBF) is described. Consisting of a momentum separator followed by an E-D-E Rochester-type mass spectrometer, the RMS is the centerpiece of the nuclear structure endstation at the HRIBF. Designed to transport ions with rigidities near K=100, the RMS has acceptances of ±10% in energy and ±4.9% in mass-to-charge ratio. Recent experimental results are used to illustrate the detection capabilities of the RMS, which is compatible with many detectors and devices

The B → D* vertical bar ν form factor at zero recoil and the determination of vertical bar Vcb vertical bar

International Nuclear Information System (INIS)

Simone, J.N.; Hashimoto, S.; Kronfeld, A.S.; Mackenzie, P.B.; Ryan, S.M.

2002-01-01

We summarize our lattice QCD study of the form factor at zero recoil in the decay B → D* vertical bar ν. After careful consideration of all sources of systematic uncertainty, we find, h A 1 (1) 0.913 +24+17 -17-30 , where the first uncertainty is from statistics and fitting while the second combined uncertainty is from all other systematic effects

First measurement of the VESUVIO neutron spectrum in the 30-80 MeV energy range using a Proton Recoil Telescope technique

Science.gov (United States)

Cazzaniga, C.; Tardocchi, M.; Croci, G.; Frost, C.; Giacomelli, L.; Grosso, G.; Hjalmarsson, A.; Rebai, M.; Rhodes, N. J.; Schooneveld, E. M.; Gorini, G.

2013-11-01

Measurements of the fast neutron energy spectrum at the ISIS spallation source are reported. The measurements were performed with a Proton Recoil Telescope consisting of a thin plastic foil placed in the neutron beam and two scintillator detectors. Results in the neutron energy range 30 MeV < En < 80 MeV are in good agreement with Monte Carlo simulations of the neutron spectrum.

Suction is kid's play: extremely fast suction in newborn seahorses

Science.gov (United States)

Van Wassenbergh, Sam; Roos, Gert; Genbrugge, Annelies; Leysen, Heleen; Aerts, Peter; Adriaens, Dominique; Herrel, Anthony

2009-01-01

Ongoing anatomical development typically results in a gradual maturation of the feeding movements from larval to adult fishes. Adult seahorses are known to capture prey by rotating their long-snouted head extremely quickly towards prey, followed by powerful suction. This type of suction is powered by elastic recoil and requires very precise coordination of the movements of the associated feeding structures, making it an all-or-none phenomenon. Here, we show that newborn Hippocampus reidi are able to successfully feed using an extremely rapid and powerful snout rotation combined with a high-volume suction, surpassing that observed in adult seahorses. An inverse dynamic analysis shows that an elastic recoil mechanism is also used to power head rotation in newborn H. reidi. This illustrates how extreme levels of performance in highly complex musculoskeletal systems can be present at birth given a delayed birth and rapid development of functionally important structures. The fact that the head skeleton of newborn seahorses is still largely cartilaginous may not be problematic because the hydrodynamic stress on the rotating snout appeared considerably lower than in adult syngnathids. PMID:19324657

Cold-target recoil-ion momentum spectroscopy for diagnostics of high harmonics of the extreme-ultraviolet free-electron laser light source at SPring-8

International Nuclear Information System (INIS)

Liu, X.-J.; Fukuzawa, H.; Pruemper, G.; Ueda, K.; Okunishi, M.; Shimada, K.; Motomura, K.; Saito, N.; Iwayama, H.; Nagaya, K.; Yao, M.; Rudenko, A.; Ullrich, J.; Foucar, L.; Czasch, A.; Schmidt-Boecking, H.; Doerner, R.; Nagasono, M.; Higashiya, A.; Yabashi, M.

2009-01-01

We have developed a cold-target recoil-ion momentum spectroscopy apparatus dedicated to the experiments using the extreme-ultraviolet light pulses at the free-electron laser facility, SPring-8 Compact SASE Source test accelerator, in Japan and used it to measure spatial distributions of fundamental, second, and third harmonics at the end station.

On Averaging Rotations

DEFF Research Database (Denmark)

Gramkow, Claus

1999-01-01

In this article two common approaches to averaging rotations are compared to a more advanced approach based on a Riemannian metric. Very offten the barycenter of the quaternions or matrices that represent the rotations are used as an estimate of the mean. These methods neglect that rotations belo...... approximations to the Riemannian metric, and that the subsequent corrections are inherient in the least squares estimation. Keywords: averaging rotations, Riemannian metric, matrix, quaternion......In this article two common approaches to averaging rotations are compared to a more advanced approach based on a Riemannian metric. Very offten the barycenter of the quaternions or matrices that represent the rotations are used as an estimate of the mean. These methods neglect that rotations belong...

Potku – New analysis software for heavy ion elastic recoil detection analysis

International Nuclear Information System (INIS)

Arstila, K.; Julin, J.; Laitinen, M.I.; Aalto, J.; Konu, T.; Kärkkäinen, S.; Rahkonen, S.; Raunio, M.; Itkonen, J.; Santanen, J.-P.; Tuovinen, T.; Sajavaara, T.

2014-01-01

Time-of-flight elastic recoil detection (ToF-ERD) analysis software has been developed. The software combines a Python-language graphical front-end with a C code computing back-end in a user-friendly way. The software uses a list of coincident time-of-flight–energy (ToF–E) events as an input. The ToF calibration can be determined with a simple graphical procedure. The graphical interface allows the user to select different elements and isotopes from a ToF–E histogram and to convert the selections to individual elemental energy and depth profiles. The resulting sample composition can be presented as relative or absolute concentrations by integrating the depth profiles over user-defined ranges. Beam induced composition changes can be studied by displaying the event-based data in fractions relative to the substrate reference data. Optional angular input data allows for kinematic correction of the depth profiles. This open source software is distributed under the GPL license for Linux, Mac, and Windows environments

Potku – New analysis software for heavy ion elastic recoil detection analysis

Energy Technology Data Exchange (ETDEWEB)

Arstila, K., E-mail: kai.arstila@jyu.fi [Department of Physics, University of Jyväskylä, P.O. Box 35, FI-40014, Jyväskylä (Finland); Julin, J.; Laitinen, M.I. [Department of Physics, University of Jyväskylä, P.O. Box 35, FI-40014, Jyväskylä (Finland); Aalto, J.; Konu, T.; Kärkkäinen, S.; Rahkonen, S.; Raunio, M.; Itkonen, J.; Santanen, J.-P.; Tuovinen, T. [Department of Mathematical Information Technology, University of Jyväskylä, P.O. Box 35, FI-40014, Jyväskylä (Finland); Sajavaara, T. [Department of Physics, University of Jyväskylä, P.O. Box 35, FI-40014, Jyväskylä (Finland)

2014-07-15

Time-of-flight elastic recoil detection (ToF-ERD) analysis software has been developed. The software combines a Python-language graphical front-end with a C code computing back-end in a user-friendly way. The software uses a list of coincident time-of-flight–energy (ToF–E) events as an input. The ToF calibration can be determined with a simple graphical procedure. The graphical interface allows the user to select different elements and isotopes from a ToF–E histogram and to convert the selections to individual elemental energy and depth profiles. The resulting sample composition can be presented as relative or absolute concentrations by integrating the depth profiles over user-defined ranges. Beam induced composition changes can be studied by displaying the event-based data in fractions relative to the substrate reference data. Optional angular input data allows for kinematic correction of the depth profiles. This open source software is distributed under the GPL license for Linux, Mac, and Windows environments.

Crowd-Sourcing Seismic Data for Education and Research Opportunities with the Quake-Catcher Network

Science.gov (United States)

Sumy, D. F.; DeGroot, R. M.; Benthien, M. L.; Cochran, E. S.; Taber, J. J.

2016-12-01

The Quake Catcher Network (QCN; quakecatcher.net) uses low cost micro-electro-mechanical system (MEMS) sensors hosted by volunteers to collect seismic data. Volunteers use accelerometers internal to laptop computers, phones, tablets or small (the size of a matchbox) MEMS sensors plugged into desktop computers using a USB connector to collect scientifically useful data. Data are collected and sent to a central server using the Berkeley Open Infrastructure for Network Computing (BOINC) distributed computing software. Since 2008, sensors installed in museums, schools, offices, and residences have collected thousands of earthquake records, including the 2010 M8.8 Maule, Chile, the 2010 M7.1 Darfield, New Zealand, and 2015 M7.8 Gorkha, Nepal earthquakes. In 2016, the QCN in the United States transitioned to the Incorporated Research Institutions for Seismology (IRIS) Consortium and the Southern California Earthquake Center (SCEC), which are facilities funded through the National Science Foundation and the United States Geological Survey, respectively. The transition has allowed for an influx of new ideas and new education related efforts, which include focused installations in several school districts in southern California, on Native American reservations in North Dakota, and in the most seismically active state in the contiguous U.S. - Oklahoma. We present and describe these recent educational opportunities, and highlight how QCN has engaged a wide sector of the public in scientific data collection, particularly through the QCN-EPIcenter Network and NASA Mars InSight teacher programs. QCN provides the public with information and insight into how seismic data are collected, and how researchers use these data to better understand and characterize seismic activity. Lastly, we describe how students use data recorded by QCN sensors installed in their classrooms to explore and investigate felt earthquakes, and look towards the bright future of the network.

Separation of fission products by the use of recoil; Separation des produits de fission par utilisation du recul

Energy Technology Data Exchange (ETDEWEB)

Henry, R; Beydon, J; Bardy, A [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

1960-07-01

We have studied fission recoil in U{sub 3}O{sub 8} organic solvent mixtures. The organic phase chosen was first naphtalene then terphenyl. Graphite and activated carbon were also tried out as recoil media. We first verified that the fission fragments are ejected from the uranium oxide particles under our experimental conditions. The retention phenomenon observed is due to an adsorption occurring either during irradiation or during the chemical treatment. Using naphthalene or terphenyl, the individual separation of the fission products has made it possible to show the influence of the chemical nature of the recoil medium on the retention of each fission product. We put forward a hypothesis concerning this phenomenon: experiments carried out using 'scavengers', together with kinetic studies make it possible to explain the retention phenomenon and to choose the most favorable conditions for reducing this retention to a low value. The thermal recombination kinetics demonstrate the influence of the fission ion charge on the final value of the retention for a given temperature. The origins of this thermal recombination are discussed. (author) [French] On a etudie le recul de fission dans les melanges U{sub 3}0{sub 8}, phase organique. La phase organique choisie a ete le naphtalene puis le terphenyle. Le graphite et le charbon actif ont egalement ete essayes comme milieux de recul. On a d'abord determine que les fragments de fission sortent des particules d'oxyde d'uranium avec un rendement de 100 pour cent dans nos conditions experimentales. Le phenomene de retention observe est du a une adsorption ayant lieu pendant l'irradiation ou pendant le traitement chimique. Dans le naphtalene et le terphenyle, la separation individuelle des produits de fission a permis de mettre en evidence l'influence de la nature chimique du milieu de recul sur la retention de chaque produit de fission. On avance une hypothese sur ce phenomene: des experiences effectuees avec des 'scavengers

Spectral flux of the p-7Li(C Q-M neutron source measured by proton recoil telescope

Directory of Open Access Journals (Sweden)

Simakov S.P.

2010-10-01

Full Text Available The cyclotron-based fast neutron source at NPI produces mono-energetic neutron fields up to 35 MeV neutron energy using the p + 7Li(carbon backing reactions. To be applied for activation cross-section measurements, not only the intensity of neutron peak, but also the contribution of low-energy continuum in the spectra must be well determined. Simulations of the spectral flux from present source at a position of irradiated samples were performed using CYRIC TOF-data validated in the present work against LA150h by calculations with the transport Monte Carlo code MCNPX. Simulated spectra were tested by absolute measurements using a proton-recoil telescope technique. The recoil-proton spectrometer consisted of a shielded scattering chamber with polyethylene and carbon radiators and the ΔE1-ΔE2-E telescope of silicon-surface detectors located to the neutron beam axis at 45° in the laboratory system. Si-detectors were handled by usual data acquisition system. Dead-time – and pulse-overlap losses of events were determined from the count rate of pulse generator registered during duty cycle of accelerator operation. The proton beam charge and data were taken in the list mode for later replay and analysis. The calculations for 7Li(p,n and 12C(p,n reactions reasonably reproduce CYRIC TOF neutron source spectra. The influence of neutron source set-up (proton beam dimensions, 7Li-foil, carbon stopper, cooling medium, target support/chamber and the geometry-arrangement of irradiated sample on the spectral flux is discussed in details.

Detection of exclusive reactions in the Hermes Recoil Fiber Tracker

International Nuclear Information System (INIS)

Keri, Tibor

2008-08-01

(Recoil Detector) with an unpolarized target at this position. This detector consists of the Silicon Strip Detector, the SFT (Scintillating Fiber Tracker), the Photon Detector and is surrounded by a 1T superconducting magnet. It provides several space points for tracking and thus momentum reconstruction. The energy deposition in the various detectors is used to achieve particle identification. The main part of the thesis work was the implementation of the SFT and the RD readout system. Before the installation of the RD a series of test runs were carried out to proof the concept of the detector, to measure the internal alignment and to prepare the installation. These test runs for the SFT are described and major results are shown. Furthermore a preliminary analysis of the latest data 06d/06d0 was carried out to show the performance of the installed Recoil Detector in combination with the HERMES forward spectrometer. (orig.)

Detection of exclusive reactions in the Hermes Recoil Fiber Tracker

Energy Technology Data Exchange (ETDEWEB)

Keri, Tibor

2008-08-15

the RD (Recoil Detector) with an unpolarized target at this position. This detector consists of the Silicon Strip Detector, the SFT (Scintillating Fiber Tracker), the Photon Detector and is surrounded by a 1T superconducting magnet. It provides several space points for tracking and thus momentum reconstruction. The energy deposition in the various detectors is used to achieve particle identification. The main part of the thesis work was the implementation of the SFT and the RD readout system. Before the installation of the RD a series of test runs were carried out to proof the concept of the detector, to measure the internal alignment and to prepare the installation. These test runs for the SFT are described and major results are shown. Furthermore a preliminary analysis of the latest data 06d/06d0 was carried out to show the performance of the installed Recoil Detector in combination with the HERMES forward spectrometer. (orig.)

 Ischemic Stroke Secondary to Aortic Dissection Following Rifle Butt Recoil Chest Injury: A Case Report

Directory of Open Access Journals (Sweden)

John Valiath

2011-11-01

Full Text Available  Ischemic stroke secondary to aortic dissection is not uncommon. We present a patient with left hemiplegia secondary to Stanford type A aortic dissection extending to the supra-aortic vessels, which was precipitated by rifle butt recoil chest injury. The diagnosis of aortic dissection was delayed due to various factors. Finally, the patient underwent successful Bentall procedure with complete resolution of symptoms. This case emphasizes the need for caution in the use of firearms for recreation and to take precautions in preventing such incidents. In addition, this case illustrates the need for prompt cardiovascular physical examination in patients presenting with stroke.

First measurement of the VESUVIO neutron spectrum in the 30–80 MeV energy range using a Proton Recoil Telescope technique

International Nuclear Information System (INIS)

Cazzaniga, C; Tardocchi, M; Croci, G; Grosso, G; Rebai, M; Gorini, G; Frost, C; Rhodes, N J; Schooneveld, E M; Giacomelli, L; Hjalmarsson, A

2013-01-01

Measurements of the fast neutron energy spectrum at the ISIS spallation source are reported. The measurements were performed with a Proton Recoil Telescope consisting of a thin plastic foil placed in the neutron beam and two scintillator detectors. Results in the neutron energy range 30 MeV n < 80 MeV are in good agreement with Monte Carlo simulations of the neutron spectrum

Measurement of the proton form factors ratio G_E/G_M to Q² = 5.6 GeV² by recoil polarimetry

Energy Technology Data Exchange (ETDEWEB)

Gayou, Olivier [College of William and Mary, Williamsburg, VA (United States)

2002-01-01

In this thesis, we present the results of the experiment E99-007, which measured the ratio of the electric to magnetic form factors of the proton to the four momentum transfer square Q² = 5.6 GeV², by recoil polarimetry. Data were taken in 2000 at the Thomas Jefferson National Accelerator Facility in Virginia, USA. A 4.6 GeV polarized electron beam was scattered off a cryogenic hydrogen target. The polarization of the recoil proton was measured in the Focal Plane Polarimeter, located after one of the two High Resolution Spectrometers in the hall. The ratio of the transverse to longitudinal components of the recoil proton polarization is proportional to the ratio of the form factors. Elastic events were selected by detecting the scattered electron in a large acceptance lead-glass calorimeter. The main result of this experiment is the linear decrease of the form factor ratio with increasing Q², corresponding to different spatial distributions of the electric charge and the magnetization. Numerous theoretical calculations show that relativistic effects, such as mixing of spin states due to Lorentz boosts, are important to account for the observed data in this critical intermediate kinematic region.

Multiple and double scattering contributions to depth resolution and low energy background in hydrogen elastic recoil detection

Energy Technology Data Exchange (ETDEWEB)

Wielunski, L.S. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), Lindfield, NSW (Australia). Div. of Applied Physics

1996-12-31

The sensitivity of hydrogen elastic recoil detection ( ERD ) is usually limited by the low energy background in the ERD spectrum. A number of 4.5 MeV He{sup ++} hydrogen ERD spectra from different hydrogen implanted samples are compared. The samples are chosen with different atomic numbers from low Z (carbon) to high Z (tungsten carbide) to observe the effects of multiple scattering and double scattering within the sample material. The experimental depth resolution and levels of the low energy background in ERD spectra are compared with theoretical predictions from multiple and double scattering. 10 refs., 2 tabs., 5 figs.

Multiple and double scattering contributions to depth resolution and low energy background in hydrogen elastic recoil detection

Energy Technology Data Exchange (ETDEWEB)

Wielunski, L S [Commonwealth Scientific and Industrial Research Organisation (CSIRO), Lindfield, NSW (Australia). Div. of Applied Physics

1997-12-31

The sensitivity of hydrogen elastic recoil detection ( ERD ) is usually limited by the low energy background in the ERD spectrum. A number of 4.5 MeV He{sup ++} hydrogen ERD spectra from different hydrogen implanted samples are compared. The samples are chosen with different atomic numbers from low Z (carbon) to high Z (tungsten carbide) to observe the effects of multiple scattering and double scattering within the sample material. The experimental depth resolution and levels of the low energy background in ERD spectra are compared with theoretical predictions from multiple and double scattering. 10 refs., 2 tabs., 5 figs.

Coincident detection of electrons ejected at large angles and target recoil ions produced in multiply ionizing collisions for the 1-MeV/u Oq++Ar collision system

International Nuclear Information System (INIS)

Gaither III, C.C.; Breinig, M.; Berryman, J.W.; Hasson, B.F.; Richards, J.D.; Price, K.

1993-01-01

The angular distributions of energetic electrons ejected at angles between 45 degree and 135 degree with respect to the incident-beam direction have been measured in coincidence with the charge states of the target recoil ions produced in multiply ionizing collisions for the 1-MeV/u O q+ (q=4,7)+Ar collision systems. These measurements have been made for ∼179-, ∼345-, and ∼505-eV electrons. Additionally, the energy distributions of electrons ejected into specific angular regions have been measured. Ar LMM satellite Auger electrons appear as a peak in the energy spectrum of electrons ejected at all large angles. The center of this peak is found at an electron energy of ∼179 eV. Electrons with ∼179 eV energy, ejected at large angles, are preferentially produced in coincidence with recoil ions of charge state 4+. Electrons with ∼345 eV energy and ∼505 eV energy ejected at large angles are preferentially produced in coincidence with recoil ions of charge state 3+. The angular distributions for these electrons are strongly peaked in the forward direction; essentially no electrons are observed at angles larger than 90 degree. These results are consistent with the dominant production mechanism for energetic electrons ejected at large angles being a binary-encounter process. Differential cross sections have been calculated from these angular distributions. They are on the order of 10 -21 cm 2 /(eV sr)

The extraction of lifetimes of weakly-populated nuclear levels in recoil distance method experiments

International Nuclear Information System (INIS)

Kennedy, D.L.; Stuchbery, A.E.; Bolotin, H.H.

1979-01-01

Two analytic techniques are described which extend the conventional analysis of recoil-distance method (RDM) data. The first technique utilizes the enhanced counting statistics of the composite spectrum formed by the addition of all γ-ray spectra recorded at the different target-to-stopper distances employed, in order to extract the lifetimes of levels whose observed depopulating γ-ray transitions have insufficient statistics to permit conventional analysis. The second technique analyses peak centroids rather than peak areas to account for contamination by flight distance dependent background. The results from a recent study of the low-lying excited states in 196 198 Pt for those levels whose lifetimes could be extracted by conventional RDM analysis are shown to be in good agreement with those obtained using the new methods of analysis

Asteroid rotation rates

International Nuclear Information System (INIS)

Binzel, R.P.; Farinella, P.

1989-01-01

Within the last decade the data base of asteroid rotation parameters (rotation rates and lightcurve amplitudes) has become sufficiently large to identify some definite rends and properties which can help us to interpret asteroid collisional evolution. Many significant correlations are found between rotation parameters and diameter, with distinct changes occurring near 125 km. The size range, which is also the diameter above which self-gravity may become important, perhaps represents a division between surviving primordial asteroids and collisional fragments. A Maxwellian is able to fit the observed rotation rate distributions of asteroids with D>125 km, implying that their rotation rates may be determined by collisional evolution. Asteroids with D<125 km show an excess of slow rotators and their non-Maxwellian distributions suggests that their rotation rates are more strongly influenced by other processes, such as the distribution resulting from their formation in catastrophic disruption events. Other correlations observed in the data set include different mean rotation rates for C, S and M type asteroids implying that their surface spectra are indicative of bulk properties

On Averaging Rotations

DEFF Research Database (Denmark)

Gramkow, Claus

2001-01-01

In this paper two common approaches to averaging rotations are compared to a more advanced approach based on a Riemannian metric. Very often the barycenter of the quaternions or matrices that represent the rotations are used as an estimate of the mean. These methods neglect that rotations belong ...... approximations to the Riemannian metric, and that the subsequent corrections are inherent in the least squares estimation.......In this paper two common approaches to averaging rotations are compared to a more advanced approach based on a Riemannian metric. Very often the barycenter of the quaternions or matrices that represent the rotations are used as an estimate of the mean. These methods neglect that rotations belong...

Lattice QCD calculation of the B(s )→D(s) *ℓν form factors at zero recoil and implications for |Vc b|

Science.gov (United States)

Harrison, Judd; Davies, Christine T. H.; Wingate, Matthew; Hpqcd Collaboration

2018-03-01

We present results of a lattice QCD calculation of B →D* and Bs→Ds* axial vector matrix elements with both states at rest. These zero recoil matrix elements provide the normalization necessary to infer a value for the CKM matrix element |Vc b| from experimental measurements of B¯ 0→D*+ℓ-ν ¯ and B¯s0→Ds*+ℓ-ν¯ decay. Results are derived from correlation functions computed with highly improved staggered quarks (HISQ) for light, strange, and charm quark propagators, and nonrelativistic QCD for the bottom quark propagator. The calculation of correlation functions employs MILC Collaboration ensembles over a range of three lattice spacings. These gauge field configurations include sea quark effects of charm, strange, and equal-mass up and down quarks. We use ensembles with physically light up and down quarks, as well as heavier values. Our main results are FB→D *(1 )=0.895 ±0.01 0stat±0.024sys and FBs→Ds*(1 )=0.883 ±0.01 2stat±0.02 8sys . We discuss the consequences for |Vc b| in light of recent investigations into the extrapolation of experimental data to zero recoil.

The design of a proton recoil telescope for 14 MeV neutron spectrometry

Energy Technology Data Exchange (ETDEWEB)

Hawkes, N.P.; Bond, D.S.; Croft, S.; Jarvis, O.N. E-mail: onj@jet.uk; Sherwood, A.C

2002-01-01

As part of the design effort for a 14 MeV neutron spectrometer for the Joint European Torus (JET), computer codes were developed to calculate the response of a proton recoil telescope comprising a proton radiator film mounted in front of a proton detector. The codes were used to optimise the geometrical configuration in terms of efficiency and resolution, bearing in mind the constraints imposed by the proposed application as a JET neutron diagnostic for the Deuterium-Tritium phase. A prototype instrument was built according to the optimised design, and tested with monoenergetic 14 MeV neutrons from the Harwell 500 keV Van de Graaff accelerator. The measured energy resolution and absolute efficiency were found to be in acceptable agreement with the calculations. Based on this work, a multi-radiator production version of the spectrometer has now been constructed and successfully deployed at JET.

The design of a proton recoil telescope for 14 MeV neutron spectrometry

International Nuclear Information System (INIS)

Hawkes, N.P.; Bond, D.S.; Croft, S.; Jarvis, O.N.; Sherwood, A.C.

2002-01-01

As part of the design effort for a 14 MeV neutron spectrometer for the Joint European Torus (JET), computer codes were developed to calculate the response of a proton recoil telescope comprising a proton radiator film mounted in front of a proton detector. The codes were used to optimise the geometrical configuration in terms of efficiency and resolution, bearing in mind the constraints imposed by the proposed application as a JET neutron diagnostic for the Deuterium-Tritium phase. A prototype instrument was built according to the optimised design, and tested with monoenergetic 14 MeV neutrons from the Harwell 500 keV Van de Graaff accelerator. The measured energy resolution and absolute efficiency were found to be in acceptable agreement with the calculations. Based on this work, a multi-radiator production version of the spectrometer has now been constructed and successfully deployed at JET

Rotator cuff exercises

Science.gov (United States)

... 25560729 . Read More Frozen shoulder Rotator cuff problems Rotator cuff repair Shoulder arthroscopy Shoulder CT scan Shoulder MRI scan Shoulder pain Patient Instructions Rotator cuff - self-care Shoulder surgery - discharge Using your ...

Recoil effects in the hyperfine structure of QED bound states

International Nuclear Information System (INIS)

Bodwin, G.T.; Yennie, D.R.; Gregorio, M.A.

1985-01-01

The authors give a general discussion of the derivation from field theory of a formalism for the perturbative solution of the relativistic two-body problem. The lowest-order expression for the four-point function is given in terms of a two-particle three-dimensional propagator in a static potential. It is obtained by fixing the loop energy in the four-dimensional formalism at a point which is independent of the loop momentum and is symmetric in the two particle variables. This method avoids awkward positive- and negative-energy projectors, with their attendant energy square roots, and allows one to recover the Dirac equation straightforwardly in the nonrecoil limit. The perturbations appear as a variety of four-dimensional kernels which are rearranged and regrouped into convenient sets. In particular, they are transformed from the Coulomb to the Feynman gauge, which greatly simplifies the expressions that must be evaluated. Although the approach is particularly convenient for the precision analysis of QED bound states, it is not limited to such applications. The authors use it to give the first unified treatment of all presently known recoil corrections to the muonium hyperfine structure and also to verify the corresponding contributions through order α 2 lnαE/sub F/ in positronium. The required integrals are evaluated analytically

Identification of fission-like events in the 16O + 181Ta system: Mass and isotopic yield distribution

International Nuclear Information System (INIS)

Sharma, Vijay R.; Yadav, Abhishek; Singh, Devendra P.; Unnati,; Singh, B. P.; Prasad, R.; Singh, Pushpendra P.; Sharma, Manoj K.; Kumar, R.; Golda, K. S.; Sinha, A. K.

2011-01-01

In this paper, nuclear reaction cross sections for 24 fission-like fragments (30≤Z≤60) have been measured for the 6.5 MeV/A 16 O + 181 Ta system. The recoil-catcher activation technique was employed followed by off-line γ spectroscopy. The isotopic yield distributions for yttrium and indium isotopes have been obtained from the experimental data. The variance of the presently measured isotopic yield distributions have been found to be in agreement with the literature values. However, the variance of the mass distribution of fission residues has found to be narrower as compared to other relatively heavier systems. A self-consistent approach to determining the isobaric charge dispersion parameters has been adopted. The measured fission cross sections at 97 and 100 MeV are satisfactorily described by a statistical model code. An attempt has been made to explain the production cross sections of intermediate mass residues in the fission of heavy residues populated via complete and/or incomplete fusion processes.

Effect of projectile structure on evaporation residue yields in incomplete fusion reactions

CERN Document Server

Babu, K S; Sudarshan, K; Shrivastava, B D; Goswami, A; Tomar, B S

2003-01-01

The excitation functions of heavy residues, representing complete and incomplete fusion products, produced in the reaction of sup 1 sup 2 C and sup 1 sup 3 C on sup 1 sup 8 sup 1 Ta have been measured over the projectile energy range of 5 to 6.5 MeV/nucleon by the recoil catcher method and off-line gamma-ray spectrometry. Comparison of the measured excitation functions with those calculated using the PACE2 code based on the statistical model revealed the occurrence of incomplete fusion reactions in the formation of alpha emission products. The fraction of incomplete fusion cross sections in the sup 1 sup 2 C + sup 1 sup 8 sup 1 Ta reaction was found to be higher, by a factor of approx 2, than that in the sup 1 sup 3 C + sup 1 sup 8 sup 1 Ta reaction. The results have been discussed in terms of the effect of alpha cluster structure of the projectile on incomplete fusion reactions.

Isotopic production cross-sections and recoil velocities of spallation-fission fragments in the reaction 238U(1A GeV)+e

CERN Document Server

Pereira, J; Wlazlo, W; Benlliure, J; Casarejos, E; Armbruster, P; Bernas, M; Enqvist, T; Legrain, R; Leray, S; Rejmund, F; Mustapha, B; Schmidt, K.-H; Stéphan, C; Taïeb, J; Tassan-Got, L; Volant, C; Boudard, A; Czajkowski, S; 10.1103/PhysRevC.75.014602

2007-01-01

Fission fragments of 1A GeV 238U nuclei interacting with a deuterium target have been investigatedwith the Fragment Separator (FRS) at GSI (Darmstadt) by measuring their isotopicproduction cross-sections and recoil velocities. The results, along with those obtained recently forspallation-evaporation fragments, provide a comprehensive analysis of the spallation nuclear productionsin the reaction 238U(1A GeV)+d. Details about experiment performance, data reductionand results will be presented.

Laboratory experiments on the formation and recoil jet transport of aerosol by laser ablation

Science.gov (United States)

Hirooka, Yoshi; Tanaka, Kazuo A.; Imamura, Keisuke; Okazaki, Katsuya

2016-05-01

In a high-repetition rate inertial fusion reactor, the first wall will be subjected to repeated ablation along with pellet implosions, which then leads to the formation of aerosol to scatter and/or deflect laser beams for the subsequent implosion, affecting the overall reactor performance. Proposed in the present work is a method of in-situ directed transport of aerosol particles by the use of laser ablation-induced jet recoil momenta. Lithium and carbon are used as the primary ablation targets, the former of which is known to form aerosol in the form of droplet, and the latter of which tends to form carbon nanotubes. Laboratory-scale experiments have been conducted to irradiate airborne aerosol particles with high-intensity laser to produce ablation-induced jet. Data have indicated a change in aerosol flow direction, but only in the case of lithium.

Rotational motion in nuclei

International Nuclear Information System (INIS)

Bohr, A.

1976-01-01

Nuclear structure theories are reviewed concerned with nuclei rotational motion. The development of the deformed nucleus model facilitated a discovery of rotational spectra of nuclei. Comprehensive verification of the rotational scheme and a successful classification of corresponding spectra stimulated investigations of the rotational movement dynamics. Values of nuclear moments of inertia proved to fall between two marginal values corresponding to rotation of a solid and hydrodynamic pattern of an unrotating flow, respectively. The discovery of governing role of the deformation and a degree of a symmetry violence for determining rotational degrees of freedon is pointed out to pave the way for generalization of the rotational spectra

g-Factor measurements of first 2+ states of heavy Te isotopes based on nuclear spin de orientation for nuclei recoiling in vacuum

International Nuclear Information System (INIS)

Danchev, M.; Pavan, J.; Stone, N.J.; Stuchbery, A.E.; Baktash, C.; Beene, J.; Benczer-Koller, N.; Bingham, C.R.; Dupak, J.; Galindo-Uribarri, A.; Gross, C.J.; Kumbartzki, G.; Radford, D.C.; Stone, J.R.; Timlin, C.L.; Yu, C.-H.; Zamfir, N.V.

2005-01-01

We demonstrate that the recoil-in-vacuum (RIV) method can be used to determine the g-factor of the Coulumb excited first 2 + state of 132 Te. This was possible owing to advantages provided by CLARION (ORNL clover multi-detector array) and the segmented charged particle detector HyBall. Calibratory experiments were performed with 122,126,13 Te and a g-factor of 132 Te was deduced g = (+)0.35(5)

Towards 100Sn with GASP + Si-ball + Recoil Mass Spectrometer: High-spin states of 105Sn and 103In

International Nuclear Information System (INIS)

De Angelis, G.; Farnea, E.; Gadea, A.; Sferrazza, M.; Ackermann, D.; Bazzacco, D.; Bednarczyk, P.; Bizzeti, P.G.; Bizzeti Sona, A.M.; Brandolini, F.; Burch, R.; Buscemi, A.; De Acuna, D.; De Poli, M.; Fahlander, C.; Li, Y.; Lipoglavsek, M.; Lunardi, S.; Makishima, A.; Menegazzo, R.; Mueller, L.; Napoli, D.; Ogawa, M.; Pavan, P.; Rossi-Alvarez, C.; Scarlassara, F.; Segato, G.F.; Seweryniak, D.; Soramel, F.; Spolaore, P.; Zanon, R.

1995-01-01

Very proton rich nuclei in the A∼100 region have been investigated using the GASP array coupled with the Recoil Mass Spectrometer (RMS) and the GASP Si-ball. High-spin states of 105 Sn and 103 In nuclei formed with the reaction 58 Ni+ 50 Cr at 210MeV have been investigated up to similar 10 and 7MeV of excitation energy respectively. We have confirmed the known excited states for both nuclei and extended to higher spin the level scheme. The experimental level schemes are compared with shell model calculations. ((orig.))

The gravitational-wave recoil from the ringdown phase of coalescing black hole binaries

International Nuclear Information System (INIS)

Le Tiec, Alexandre; Blanchet, Luc; Will, Clifford M

2010-01-01

The gravitational recoil or 'kick' of a black hole formed from the merger of two orbiting black holes, and caused by the anisotropic emission of gravitational radiation, is an astrophysically important phenomenon. We combine (i) an earlier calculation, using post-Newtonian theory, of the kick velocity accumulated up to the merger of two non-spinning black holes, (ii) a 'close-limit approximation' calculation of the radiation emitted during the ringdown phase, and based on a solution of the Regge-Wheeler and Zerilli equations using initial data accurate to second post-Newtonian order. We prove that ringdown radiation produces a significant 'anti-kick'. Adding the contributions due to inspiral, merger and ringdown phases, our results for the net kick velocity agree with those from numerical relativity to 10-15% over a wide range of mass ratios, with a maximum velocity of 180 km s -1 at a mass ratio of 0.38. (fast track communication)

ASTROPHYSICS. Exclusion of leptophilic dark matter models using XENON100 electronic recoil data.

Science.gov (United States)

2015-08-21

Laboratory experiments searching for galactic dark matter particles scattering off nuclei have so far not been able to establish a discovery. We use data from the XENON100 experiment to search for dark matter interacting with electrons. With no evidence for a signal above the low background of our experiment, we exclude a variety of representative dark matter models that would induce electronic recoils. For axial-vector couplings to electrons, we exclude cross sections above 6 × 10(-35) cm(2) for particle masses of m(χ) = 2 GeV/c(2). Independent of the dark matter halo, we exclude leptophilic models as an explanation for the long-standing DAMA/LIBRA signal, such as couplings to electrons through axial-vector interactions at a 4.4σ confidence level, mirror dark matter at 3.6σ, and luminous dark matter at 4.6σ. Copyright © 2015, American Association for the Advancement of Science.

Recoil and Vibration in an Archery Bow Equipped with a Multi-Rod Stabilizer

Directory of Open Access Journals (Sweden)

Igor Zaniewski

2012-01-01

Full Text Available The aim of this research is to create a mechanical and mathematical model of a multi-rod stabilizer for the sport archery bow and to analyze its capability to damp disagreeable recoil and vibration of the bow during internal ballistic motion. The research methods are based on the Euler-Bernoulli theory of beam bending, Lagrange equations of the second kind, the Cauchy problem, and the Runge-Kutta method. A mathematical software package was used to analyze the problem. The approach to the problem of sport-bow stabilization in the vertical plane that is proposed in this paper addresses the practical needs both of applied engineering mechanics and of the sport of archery. Numerical results from computer simulation are presented in both tabular and graphical form. The common motion of the string and arrow (internal ballistic motion is accompanied by intense vibration which is caused by disruption of the static force balance at the moment of string release.

The fuzzy bag and baryonic properties with center of mass and recoil corrections

International Nuclear Information System (INIS)

Pilotto, F.

2003-01-01

The fuzzy bag is a hadronic model which has features both of the bag model (energy-momentum conservation, QCD vacuum energy) and of relativistic potential models (confinement achieved through a potential). It is also a chiral model, with the unique property that the pion field is suppressed in the interior of the bag by means of a scalar potential, and yet chiral symmetry is preserved. This scalar potential allows one to control how far the pion field can penetrate in the interior of the bag. We calculate the masses of the fundamental baryon octet taking into account the center of mass, one-gluon exchange and one-pion exchange corrections. We also calculate the nucleon axial charge, charge radii and magnetic moments including center of mass and recoil corrections. The agreement with experiment is excellent, and the results indicate that the pion field is suppressed only very close to the center of the bag. (orig.)