Simulation study of the beam-beam interaction at SPEAR

International Nuclear Information System (INIS)

Tennyson, J.

1980-01-01

A two dimensional simulation study of the beam-beam interaction at SPEAR indicates that quantum fluctuations affecting the horizontal betatron oscillation play a critical role in the vertical beam blowup

Numerical modeling of secondary side thermohydraulics of horizontal steam generator

Energy Technology Data Exchange (ETDEWEB)

Melikhov, V.I.; Melikhov, O.I.; Nigmatulin, B.I. [Research and Engineering Centre of LWR Nuclear Plants Safety, Moscow (Russian Federation)

1995-12-31

A mathematical model for the transient three-dimensional secondary side thermal hydraulics of the horizontal steam generator has been developed. The calculations of the steam generator PGV-1000 and PGV-4 nominal regimes and comparison of numerical and experimental results have been carried out. 7 refs.

Numerical modeling of secondary side thermohydraulics of horizontal steam generator

Energy Technology Data Exchange (ETDEWEB)

Melikhov, V I; Melikhov, O I; Nigmatulin, B I [Research and Engineering Centre of LWR Nuclear Plants Safety, Moscow (Russian Federation)

1996-12-31

A mathematical model for the transient three-dimensional secondary side thermal hydraulics of the horizontal steam generator has been developed. The calculations of the steam generator PGV-1000 and PGV-4 nominal regimes and comparison of numerical and experimental results have been carried out. 7 refs.

Beam-beam diagnostics from closed-orbit distortion

International Nuclear Information System (INIS)

Furman, M.; Chin, Y.H.; Eden, J.; Kozanecki, W.; Tennyson, J.; Ziemann, V.

1992-07-01

We study the applicability of beam-beam deflection techniques as a tuning tool for asymmetric B factories, focusing on PEP-II as an example. Assuming that the closed orbits of the two beams are separated vertically at the interaction point by a local orbit bump that is nominally closed, we calculate the residual beam orbit distortions due to the beam-beam interaction. Difference orbit measurements, performed at points conveniently distant from the interaction point (IP), provide distinct signatures that can be used to maintain the beams in collision and perform detailed optical diagnostics at the IP. A proposal to test this method experimentally at the TRISTAN ring is briefly discussed

Beam-beam effect and luminosity in SPEAR

International Nuclear Information System (INIS)

Wiedemann, H.

1980-07-01

Measurements performed at SPEAR have been discussed and scaling laws for the maximum luminosity and the maximum linear tune shift parameter with energy are shown. There are two distinct regimes, one below 2 GeV where the linear tune shift parameter scales like xi/sub y/ approx. E 2 4 and the other regime where this parameter is constant xi/sub y/ approx. = 0.05 to 0.06. In the lower energy regime the limit is reached when the vertical beam size is blown up to the acceptance of the storage ring. A significant (< 10%) horizontal beam blow up is not observed and the value of the horizontal linear tune shift parameter xi/sub x/ does not seem to be related to the beam-beam limit

Ghost reflections of Gaussian beams in anamorphic optical systems with an application to Michelson interferometer.

Science.gov (United States)

Abd El-Maksoud, Rania H

2016-02-20

In this paper, a methodology is developed to model and analyze the effect of undesired (ghost) reflections of Gaussian beams that are produced by anamorphic optical systems. The superposition of these beams with the nominal beam modulates the nominal power distribution at the recording plane. This modulation may cause contrast reduction, veiling parts of the nominal image, and/or the formation of spurious interference fringes. The developed methodology is based on synthesizing the beam optical paths into nominal and ghost optical beam paths. Similar to the nominal beam, we present the concept that each ghost beam is characterized by a beam size, wavefront radius of curvature, and Gouy phase in the paraxial regime. The nominal and ghost beams are sequentially traced through the system and formulas for estimating the electric field magnitude and phase of each ghost beam at the recording plane are presented. The effective electric field is the addition of the individual nominal and ghost electric fields. Formulas for estimating Gouy phase, the shape of the interference fringes, and the central interference order are introduced. As an application, the theory of the formation of the interference fringes by Michelson interferometer is presented. This theory takes into consideration the ghost reflections that are formed by the beam splitter. To illustrate the theory and to show its wide applicability, simulation examples that include a Mangin mirror, a Michelson interferometer, and a black box optical system are provided.

Observations of beam-beam effects in the LHC 2011

International Nuclear Information System (INIS)

Herr, W.; Alemany, R.; Buffat, X.; Calaga, R.; Giachino, R.; Papotti, G.; Pieloni, T.; Trad, G.; Schaumann, M.

2012-01-01

We have reported on the first studies of beam-beam effects in the LHC with high intensity, high brightness beams and can summarize the results as follows. The effect of the beam-beam interaction on the beam dynamics is clearly established. The LHC allows very large head-on tune shifts above nominal. The effect of long range interactions on the beam lifetime and losses (dynamic aperture) is clearly visible. The number of head-on and/or long range interactions important for losses and all predicted PACMAN effects have been observed. All observations are in good agreement with the expectations

Closed orbit distortion and the beam-beam interaction

Energy Technology Data Exchange (ETDEWEB)

Furman, M.; Chin, Y.H.; Eden, J. [Lawrence Berkeley Lab., CA (United States); Kozanecki, W. [CEA Centre d`Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France)]|[Stanford Linear Accelerator Center, Menlo Park, CA (United States); Tennyson, J.; Ziemann, V. [Stanford Linear Accelerator Center, Menlo Park, CA (United States)

1992-06-01

We study the applicability of beam-beam deflection techniques as a tuning tool for the SLAC/LBL/LLNL B factory, PEP-II. Assuming that the closed orbits of the two beams are separated vertically at the interaction point by a local orbit bump that is nominally closed, we calculate the residual beam orbit distortions due to the beam-beam interaction. Difference orbit measurements, performed at points conveniently distant from the IP, provide distinct coordinate- or frequency-space signatures that can be used to maintain the beams in collision and perform detailed optical diagnostics at the IP. A proposal to test this method experimentally at the TRISTAN ring is briefly discussed.

Closed orbit distortion and the beam-beam interaction

International Nuclear Information System (INIS)

Furman, M.; Chin, Y.H.; Eden, J.; Kozanecki, W.; Tennyson, J.; Ziemann, V.

1992-01-01

We study the applicability of beam-beam deflection techniques as a tuning tool for the SLAC/LBL/LLNL B factory, PEP-II. Assuming that the closed orbits of the two beams are separated vertically at the interaction point by a local orbit bump that is nominally closed, we calculate the residual beam orbit distortions due to the beam-beam interaction. Difference orbit measurements, performed at points conveniently distant from the IP, provide distinct coordinate- or frequency-space signatures that can be used to maintain the beams in collision and perform detailed optical diagnostics at the IP. A proposal to test this method experimentally at the TRISTAN ring is briefly discussed

A self-decoupling piezoresistive sensor for measuring microforce in horizontal and vertical directions

International Nuclear Information System (INIS)

Zhou, Jie; Rong, Weibin; Wang, Lefeng; Gao, Peng; Sun, Lining

2016-01-01

This paper presents the design, fabrication and calibration of a novel two-dimension microforce sensor with nano-Newton resolution. The sensor, mainly composed of a clamped–clamped beam (horizontal detecting beam), an overhanging beam (vertical detecting beam) and a half-folded beam, is highly sensitive to microforces in the horizontal (parallel to the probe of the designed sensor) and vertical (perpendicular to the wafer surface) directions. The four vertical sidewall surface piezoresistors (horizontal piezoresistors) and two surface piezoresistors (vertical piezoresistors) were fabricated to achieve the requirements of two-dimension microforce measurements. Combining the sensor structure with Wheatstone bridge configurations, the microforce decoupling among the x , y , and z direction can be realized. Accordingly, the sensor is capable of detecting microforces in the horizontal and vertical directions independently. The calibration results verified that the sensor sensitivities at room temperature are 210.58 V N −1 and 159.2 V N −1 in the horizontal and vertical directions, respectively. Additionally, the sensor’s corresponding force resolutions are estimated at 2 nN and 3 nN in theory, respectively. The sensor can be used to measure the contact force between manipulating tools and micro-objects, in fields such as microassembly and biological assays. (paper)

Dual-beam CRT

International Nuclear Information System (INIS)

1975-01-01

A dual-beam cathode-ray tube having a pair of electron guns and associated deflection means disposed side-by-side on each side of a central axis is described. The electron guns are parallel and the deflection means includes beam centering plates and angled horizontal deflection plates to direct the electron beams toward the central axis, precluding the need for a large-diameter tube neck in which the entire gun structures are angled. Bowing control plates are disposed adjacent to the beam centering plates to minimize trace bowing, and an intergun shield is disposed between the horizontal deflection plates to control and correct display pattern geometry distortion

Hydrodynamic calculations of 20-TeV beam interactions with the SSC beam dump

International Nuclear Information System (INIS)

Wilson, D.C.; Wingate, C.A.; Goldstein, J.C.; Godwin, R.P.; Mokhov, N.V.

1993-01-01

The 300μs, 400 MJ SSC proton beam must be contained when extracted to the external beam dump. The current design for the SSC beam dump can tolerate the beat load produced if the beam is deflected into a raster scan over the face of the dump. If the high frequency deflecting magnet were to fail, the beam would scan a single strip across the dump face resulting in higher local energy deposition. This could vaporize some material and lead to high pressures. Since the beam duration is comparable to the characteristic time of expected hydrodynamic motions, we have combined the static energy deposition capability of the MARS computer code with the two- and three-dimensional hydrodynamics of the MBA and SPHINX codes. EOS data suggest an energy deposition threshold of 15 kJ/g, below which hydrodynamic effects are minimal. Above this our 2D calculations show a hole boring rate of 7 cm/μs for the nominal beam, and pressures of a few kbar. Scanning the nominal beam faster than 0.08 cm/μs should minimize hydrodynamic effects. 3D calculations support this

Full-Scale Testing of Thermoplastic Composite I-Beams for Bridges

Science.gov (United States)

2017-06-01

beams retained residual deformations after each load cycle. Therefore, a large capacity-reduction factor is advisable for future strength designs...3 Figure 3. Nominal beam dimensions (not to scale...Figure 39. Nominal dimension of machine-cut dog-bone tension specimens. .................. 43 Figure 40. Dog-bone specimen for tensile strength

Beam-scanning system for determination of beam profiles and form factors in merged-beam experiments

International Nuclear Information System (INIS)

Keyser, C.J.; Froelich, H.R.; Mitchell, J.B.A.; McGowan, J.W.

1979-01-01

A beam-scanning system for a merged electron-ion beam experiment is described. This system is used to determine the horizontal and vertical beam profiles and the form factors at three different locations along the axis of the beams. Design details of the wedge-shaped scanners and the electronic circuit for obtaining beam profiles and form factors are described. The form factor derivation for merged beams is given and an expression in terms of measured quantities is derived. (author)

Long-range beam-beam experiments in the relativistic heavy ion collider

International Nuclear Information System (INIS)

Calaga, R; Fischer, W; Milas, N; Robert-Demolaize, G

2014-01-01

Long-range beam-beam effects are a potential limit to the LHC performance with the nominal design parameters, and certain upgrade scenarios under discussion. To mitigate long-range effects, current carrying wires parallel to the beam were proposed and space is reserved in the LHC for such wires. Two current carrying wires were installed in RHIC to study the effect of strong long-range beam-beam effects in a collider, as well as test the compensation of a single long-range interaction. The experimental data were used to benchmark simulations. We summarize this work

A better beam quality

CERN Multimedia

CERN Bulletin

2010-01-01

Progress has been made on two fronts, providing physics data and preparing for higher intensities. Over the Whitsun weekend of May 22 to 24, 5 fills for physics provided almost 30 hours of stable colliding beams, all with bunch intensities around 2x1010 protons and at a β* of 2m. The first three of these fills were with 6 bunches per beam, giving 3 pairs of collisions in all experiments. For the other two fills, the number of bunches per beam was increased to 13, giving 8 pairs of colliding bunches, and for the first time luminosities were pushed above 1029 cm-2s-1, 2 orders of magnitude higher than first collisions in March. In between and after these physics fills, nominal bunches of 1011 protons were successfully ramped and brought into collision in ATLAS and CMS for the first time (not in stable beam conditions and without squeeze). Event rates seen by the experiments were in the expected range for these conditions. In the middle of this work, a short fill with beams of 7 nominal bunches was ...

Correction of beam-beam effects in luminosity measurement at ILC

CERN Document Server

Lukic, S

2015-01-01

Three methods for handling beam-beam effects in luminosity measurement at ILC are tested and evaluated in this work. The first method represents an optimization of the LEPtype asymmetric selection cuts that reduce the counting biases. The second method uses the experimentally reconstructed shape of the √ s ′ spectrum to determine the Beamstrahlung component of the bias. The last, recently proposed, collision-frame method relies on the reconstruction of the collision-frame velocity to define the selection function in the collision frame both in experiment and in theory. Thus the luminosity expression is insensitive to the difference between the CM frame of the collision and the lab frame. The collision-frame method is independent of the knowledge of the beam parameters, and it allows an accurate reconstruction of the luminosity spectrum above 80% of the nominal CM energy. However, it gives no precise infromation about luminosity below 80% of the nominal CM energy. The compatibility of diverse selection cut...

Design and construction of two 10.8 T.m superconducting beam bending magnets

International Nuclear Information System (INIS)

Dow, P.; Kesseler, G.

1978-01-01

Constructional details are given of two superconducting beam bending magnets built at CERN in 1975-77. Each magnet unit has a bending power of 10.8 T.m at the nominal current of 700 A, corresponding to a central induction of 4.75 T in a cold bore of 74 mm diameter. An 'intersecting-ellipses' coil configuration is approximated by 36 horizontally wound racetrack layers of rectangular cross-section with 90 0 bends at the coil ends. A cold-iron magnetic shield serves, in addition, as retaining structure for the electromagnetic forces. The vacuum-insulated liquid helium vessel is surrounded by a radiation shield cooled by helium boil-off gas and supported by a fibre-glass/ stainless steel suspension system. The cryogenic losses of each magnet cryostat are approximately 4 W excluding transfer losses. After successful tests the magnets were placed in a particle beam where they have been regularly operated on automatic control for about one year. (Auth.)

A prospect for the development of an epithermal neutron beam from the horizontal channel at the TRNC for brain tumors treatment based on the BNCT method

International Nuclear Information System (INIS)

Ben-Ghazail, Mustafa Ali

2005-01-01

In this work the epithermal neutron was development from horizontal channel VI at Tajoura research reactor which can be used for Boron Neutron Capture Therapy. The analysis of reactivity and control rod worth is performed by three dimensional continues energy MCNP-4C code with neutron cross section data from the ENDF/B-VI evaluation. The neutron beam which is developed for medical purpose is generated from the reactor core by means of U-235 fission. The neutrons leaking through the cavity of HC in Be-9 reflector is guided through a tube made of stainless steel to patient position. The HC has two wheels. The first wheel is small and is used as a gate. The second is large and have three positions one to close the gate, the second to open the gate while the third for loading collimator. The collimator consists of the moderators and filters to optimize the neutron beam which is installed in the loading position. The HC VI is extended to the room constructed to allow space for other horizontal channels users. materials are used to optimize the neutron beam which was selected depending on neutron beam properties related to core loading and control rod position. The results of the development study show that the required values for the neutron beam characteristic can be nearly reached. The different comparisons of the calculations performed using MCNP-4C code with the requirements values of characteristics neutron beam show that the result values of MCNP-4C code model are reliable. (author)

A horizontal multi-purpose microbeam system

Science.gov (United States)

Xu, Y.; Randers-Pehrson, G.; Marino, S. A.; Garty, G.; Harken, A.; Brenner, D. J.

2018-04-01

A horizontal multi-purpose microbeam system with a single electrostatic quadruplet focusing lens has been developed at the Columbia University Radiological Research Accelerator Facility (RARAF). It is coupled with the RARAF 5.5 MV Singleton accelerator (High Voltage Engineering Europa, the Netherlands) and provides micrometer-size beam for single cell irradiation experiments. It is also used as the primary beam for a neutron microbeam and microPIXE (particle induced x-ray emission) experiment because of its high particle fluence. The optimization of this microbeam has been investigated with ray tracing simulations and the beam spot size has been verified by different measurements.

The Mechanics of a Cantilever Beam with an Embedded Horizontal Crack Subjected to an End Transverse Force, Part A: Modelling

Directory of Open Access Journals (Sweden)

Panos G. Charalambides

2016-05-01

Full Text Available This study addresses the mechanics of a cracked cantilever beam subjected to a transverse force applied at it’s free end. In this Part A of a two Part series of papers, emphasis is placed on the development of a four-beam model for a beam with a fully embedded horizontal sharp crack. The beam aspect ratio, crack length and crack centre location appear as general model parameters. Rotary springs are introduced at the crack tip cross sections as needed to account for the changes in the structural compliance due to the presence of the sharp crack and augmented load transfer through the near-tip transition regions. Guided by recent finite element findings reported elsewhere, the four-beam model is advanced by recognizing two key observations, (a the free surface and neutral axis curvatures of the cracked beam at the crack center location match the curvature of a healthy beam (an identical beam without a crack under the same loading conditions, (b the neutral axis rotations (slope of the cracked beam in the region between the applied load and the nearest crack tip matches the corresponding slope of the healthy beam. The above observations led to the development of close form solutions for the resultant forces (axial and shear and moment acting in the beams above and below the crack. Axial force and bending moment predictions are found to be in excellent agreement with 2D finite element results for all normalized crack depths considered. Shear force estimates dominating the beams above and below the crack as well as transition region length estimates are also obtained. The model developed in this study is then used along with 2D finite elements in conducting parametric studies aimed at both validating the model and establishing the mechanics of the cracked system under consideration. The latter studies are reported in the companion paper Part B-Results and Discussion.

Trajectory measurements and correlations in the final focus beam line at the KEK Accelerator Test Facility

Science.gov (United States)

Renier, Y.; Bambade, P.; Tauchi, T.; White, G. R.; Boogert, S.

2013-06-01

The Accelerator Test Facility 2 (ATF2) commissioning group aims to demonstrate the feasibility of the beam delivery system of the next linear colliders (ILC and CLIC) as well as to define and to test the tuning methods. As the design vertical beam sizes of the linear colliders are about few nanometers, the stability of the trajectory as well as the control of the aberrations are very critical. ATF2 commissioning started in December 2008, and thanks to submicron resolution beam position monitors (BPMs), it has been possible to measure the beam position fluctuation along the final focus of ATF2 during the 2009 runs. The optics was not the nominal one yet, with a lower focusing to make the tuning easier. In this paper, a method to measure the noise of each BPM every pulse, in a model-independent way, will be presented. A method to reconstruct the trajectory’s fluctuations is developed which uses the previously determined BPM resolution. As this reconstruction provides a measurement of the beam energy fluctuations, it was also possible to measure the horizontal and vertical dispersion function at each BPMs parasitically. The spatial and angular dispersions can be fitted from these measurements with uncertainties comparable with usual measurements.

Trajectory measurements and correlations in the final focus beam line at the KEK Accelerator Test Facility

Directory of Open Access Journals (Sweden)

Y. Renier

2013-06-01

Full Text Available The Accelerator Test Facility 2 (ATF2 commissioning group aims to demonstrate the feasibility of the beam delivery system of the next linear colliders (ILC and CLIC as well as to define and to test the tuning methods. As the design vertical beam sizes of the linear colliders are about few nanometers, the stability of the trajectory as well as the control of the aberrations are very critical. ATF2 commissioning started in December 2008, and thanks to submicron resolution beam position monitors (BPMs, it has been possible to measure the beam position fluctuation along the final focus of ATF2 during the 2009 runs. The optics was not the nominal one yet, with a lower focusing to make the tuning easier. In this paper, a method to measure the noise of each BPM every pulse, in a model-independent way, will be presented. A method to reconstruct the trajectory’s fluctuations is developed which uses the previously determined BPM resolution. As this reconstruction provides a measurement of the beam energy fluctuations, it was also possible to measure the horizontal and vertical dispersion function at each BPMs parasitically. The spatial and angular dispersions can be fitted from these measurements with uncertainties comparable with usual measurements.

Commissioning of a medical accelerator photon beam Monte Carlo simulation using wide-field profiles

International Nuclear Information System (INIS)

Pena, J; Franco, L; Gomez, F; Iglesias, A; Lobato, R; Mosquera, J; Pazos, A; Pardo, J; Pombar, M; RodrIguez, A; Sendon, J

2004-01-01

A method for commissioning an EGSnrc Monte Carlo simulation of medical linac photon beams through wide-field lateral profiles at moderate depth in a water phantom is presented. Although depth-dose profiles are commonly used for nominal energy determination, our study shows that they are quite insensitive to energy changes below 0.3 MeV (0.6 MeV) for a 6 MV (15 MV) photon beam. Also, the depth-dose profile dependence on beam radius adds an additional uncertainty in their use for tuning nominal energy. Simulated 40 cm x 40 cm lateral profiles at 5 cm depth in a water phantom show greater sensitivity to both nominal energy and radius. Beam parameters could be determined by comparing only these curves with measured data

Commissioning of a medical accelerator photon beam Monte Carlo simulation using wide-field profiles

Energy Technology Data Exchange (ETDEWEB)

Pena, J [Departamento de Fisica de PartIculas, Facultade de Fisica, 15782 Santiago de Compostela (Spain); Franco, L [Departamento de Fisica de PartIculas, Facultade de Fisica, 15782 Santiago de Compostela (Spain); Gomez, F [Departamento de Fisica de PartIculas, Facultade de Fisica, 15782 Santiago de Compostela (Spain); Iglesias, A [Departamento de Fisica de PartIculas, Facultade de Fisica, 15782 Santiago de Compostela (Spain); Lobato, R [Hospital ClInico Universitario de Santiago, Santiago de Compostela (Spain); Mosquera, J [Hospital ClInico Universitario de Santiago, Santiago de Compostela (Spain); Pazos, A [Departamento de Fisica de PartIculas, Facultade de Fisica, 15782 Santiago de Compostela (Spain); Pardo, J [Departamento de Fisica de PartIculas, Facultade de Fisica, 15782 Santiago de Compostela (Spain); Pombar, M [Hospital ClInico Universitario de Santiago, Santiago de Compostela (Spain); RodrIguez, A [Departamento de Fisica de PartIculas, Facultade de Fisica, 15782 Santiago de Compostela (Spain); Sendon, J [Hospital ClInico Universitario de Santiago, Santiago de Compostela (Spain)

2004-11-07

A method for commissioning an EGSnrc Monte Carlo simulation of medical linac photon beams through wide-field lateral profiles at moderate depth in a water phantom is presented. Although depth-dose profiles are commonly used for nominal energy determination, our study shows that they are quite insensitive to energy changes below 0.3 MeV (0.6 MeV) for a 6 MV (15 MV) photon beam. Also, the depth-dose profile dependence on beam radius adds an additional uncertainty in their use for tuning nominal energy. Simulated 40 cm x 40 cm lateral profiles at 5 cm depth in a water phantom show greater sensitivity to both nominal energy and radius. Beam parameters could be determined by comparing only these curves with measured data.

Calorimetric measurement of the power of high-intensity electron beams

International Nuclear Information System (INIS)

Radak, B.B.; Radosevic, E.; Secerov, B.L.

1987-01-01

A quasi-adiabatic calorimeter is described by which the principal electron beam parameters, viz. electron energy, beam current and (separately) beam power, were determined. The nominal beam power at which these measurements were made was 3 kW (2 mA and 1500 kV). The electron energy was also determined from their range in polyethylene by using the same calorimeter as detector. Considerably lower values than nominal were found both for current (1.56 mA instead of 2.0 mA) and for energy (1260 keV instead of 1500 keV), which brought down the beam power by one third. The reliability and confidence of results was cross-checked and a good mutual agreement was found. (orig.)

Simulation of wire-compensation of long range beam beam interaction in high energy accelerators

International Nuclear Information System (INIS)

Dorda, U.; )

2006-01-01

Full text: We present weak-strong simulation results for the effect of long-range beam-beam (LRBB) interaction in LHC as well as for proposed wire compensation schemes or wire experiments, respectively. In particular, we discuss details of the simulation model, instability indicators, the effectiveness of compensation, the difference between nominal and PACMAN bunches for the LHC, beam experiments, and wire tolerances. The simulations are performed with the new code BBTrack. (author)

SPIDER beam dump as diagnostic of the particle beam

Energy Technology Data Exchange (ETDEWEB)

Zaupa, M., E-mail: matteo.zaupa@igi.cnr.it; Sartori, E. [Università degli Studi di Padova, Via 8 Febbraio 2, Padova 35122 (Italy); Consorzio RFX, Corso Stati Uniti 4, Padova 35127 (Italy); Dalla Palma, M.; Brombin, M.; Pasqualotto, R. [Consorzio RFX, Corso Stati Uniti 4, Padova 35127 (Italy)

2016-11-15

The beam power produced by the negative ion source for the production of ion of deuterium extracted from RF plasma is mainly absorbed by the beam dump component which has been designed also for measuring the temperatures on the dumping panels for beam diagnostics. A finite element code has been developed to characterize, by thermo-hydraulic analysis, the sensitivity of the beam dump to the different beam parameters. The results prove the capability of diagnosing the beam divergence and the horizontal misalignment, while the entity of the halo fraction appears hardly detectable without considering the other foreseen diagnostics like tomography and beam emission spectroscopy.

Low-energy beam transport studies supporting the spallation neutron source 1-MW beam operation.

Science.gov (United States)

Han, B X; Kalvas, T; Tarvainen, O; Welton, R F; Murray, S N; Pennisi, T R; Santana, M; Stockli, M P

2012-02-01

The H(-) injector consisting of a cesium enhanced RF-driven ion source and a 2-lens electrostatic low-energy beam transport (LEBT) system supports the spallation neutron source 1 MW beam operation with ∼38 mA beam current in the linac at 60 Hz with a pulse length of up to ∼1.0 ms. In this work, two important issues associated with the low-energy beam transport are discussed: (1) inconsistent dependence of the post-radio frequency quadrupole accelerator beam current on the ion source tilt angle and (2) high power beam losses on the LEBT electrodes under some off-nominal conditions compromising their reliability.

WEBEXPIR: Windowless target electron beam experimental irradiation

International Nuclear Information System (INIS)

Dierckx, Marc; Schuurmans, Paul; Heyse, Jan; Rosseel, Kris; Tichelen, Katrien Van; Nactergal, Benoit; Vandeplassche, Dirk; Aoust, Thierry; Abs, Michel; Guertin, Arnaud; Buhour, Jean-Michel; Cadiou, Arnaud; Abderrahim, Hamid Ait

2008-01-01

The windowless target electron beam experimental irradiation (WEBEXPIR) program was set-up as part of the MYRRHA/XT-ADS R and D effort on the spallation target design to investigate the interaction of a proton beam with a liquid lead-bismuth eutectic (LBE) free surface. In particular, possible free surface distortion or shockwave effects in nominal conditions and during sudden beam on/off transient situations, as well as possible enhanced evaporation were assessed. An experiment was conceived at the IBA TT-1000 Rhodotron, where a 7 MeV electron beam was used to simulate the high power deposition at the MYRRHA/XT-ADS LBE free surface. The geometry and the LBE flow characteristics in the WEBEXPIR set-up were made as representative as possible of the actual situation in the MYRRHA/XT-ADS spallation target. Irradiation experiments were carried out at beam currents of up to 10 mA, corresponding to 40 times the nominal beam current necessary to reproduce the MYRRHA/XT-ADS conditions. Preliminary analyses show that the WEBEXPIR free surface flow was not disturbed by the interaction with the electron beam and that vacuum conditions stayed well within the design specifications

Beam pointing direction changes in a misaligned Porro prism resonator

Science.gov (United States)

Lee, Jyh-Fa; Leung, Chung-Yee

1988-07-01

The relative change of the beam pointing direction for a misaligned Porro prism resonator has been analyzed, using an oscillation axis concept for the Porro prism resonator to find the beam direction. Expressions for the beam tilting angles are presented which show that the angular misalignment in the horizontal direction will result in beam tilting in both the horizontal and vertical directions. Good agreement between experimental and theoretical results is found.

Testing beam-induced quench levels of LHC superconducting magnets

CERN Document Server

Auchmann, B.; Bednarek, M.; Bellodi, G.; Bracco, C.; Bruce, R.; Cerutti, F.; Chetvertkova, V.; Dehning, B.; Granieri, P.P.; Hofle, W.; Holzer, E.B.; Lechner, A.; Del Busto, E. Nebot; Priebe, A.; Redaelli, S.; Salvachua, B.; Sapinski, M.; Schmidt, R.; Shetty, N.; Skordis, E.; Solfaroli, M.; Steckert, J.; Valuch, D.; Verweij, A.; Wenninger, J.; Wollmann, D.; Zerlauth, M.

2015-06-25

In the years 2009-2013 the Large Hadron Collider (LHC) has been operated with the top beam energies of 3.5 TeV and 4 TeV per proton (from 2012) instead of the nominal 7 TeV. The currents in the superconducting magnets were reduced accordingly. To date only seventeen beam-induced quenches have occurred; eight of them during specially designed quench tests, the others during injection. There has not been a single beam- induced quench during normal collider operation with stored beam. The conditions, however, are expected to become much more challenging after the long LHC shutdown. The magnets will be operating at near nominal currents, and in the presence of high energy and high intensity beams with a stored energy of up to 362 MJ per beam. In this paper we summarize our efforts to understand the quench levels of LHC superconducting magnets. We describe beam-loss events and dedicated experiments with beam, as well as the simulation methods used to reproduce the observable signals. The simulated energy depositio...

Nominal Mass?

Science.gov (United States)

Attygalle, Athula B; Pavlov, Julius

2017-08-01

The current IUPAC-recommended definition of the term "nominal mass," based on the most abundant naturally occurring stable isotope of an element, is flawed. We propose that Nominal mass should be defined as the sum of integer masses of protons and neutrons in any chemical species. In this way, all isotopes and isotopologues can be assigned a definitive identifier. Graphical Abstract ᅟ.

A comparison of protocols for external beam radiotherapy beam calibrations

International Nuclear Information System (INIS)

Saeed Al-Ahbabi, Salma; Bradley, D.A.; Beyomi, M.; Alkatib, Z.; Adhaheri, S.; Darmaki, M.; Nisbet, A.

2012-01-01

A number of codes of practice (CoP) for electron and photon radiotherapy beam dosimetry are currently in use. Comparison is made of the more widely used of these, specifically those of the International Atomic Energy Agency (IAEA TRS-398), the American Association of Physicists in Medicine (AAPM TG-51) and the Institute of Physics and Engineering in Medicine (IPEM 2003). All are based on calibration of ionization chambers in terms of absorbed dose to water, each seeking to reduce uncertainty in delivered dose, providing an even stronger system of primary standards than previous air-kerma based approaches. They also provide a firm, traceable and straight-forward formalism. Included in making dose assessments for the three CoP are calibration coefficients for a range of beam quality indices. Measurements have been performed using clinical photon and electron beams, the absorbed dose to water being obtained following the recommendations given by each code. Electron beam comparisons have been carried out using measurements for electron beams of nominal energies 6, 9, 12, 16 and 20 MeV. Comparisons were also carried out for photon beams of nominal energies 6 and 18 MV. For photon beams use was made of NE2571 cylindrical graphite walled ionization chambers, cross-calibrated against an NE2611 Secondary Standard; for electron beams, PTW Markus and NACP-02 plane-parallel chambers were used. Irradiations were made using Varian 600C/2100C linacs, supported by water tanks and Virtual Water™ phantoms. The absorbed doses for photon and electron beams obtained following these CoP are all in good agreement, with deviations of less than 2%. A number of studies have been carried out by different groups in different countries to examine the consistency of dosimetry codes of practice or protocols. The aim of these studies is to confirm that the goal of those codes is met, namely uniformity in establishment of dosimetry of all radiation beam types used in cancer therapy in the world

A symplectic coherent beam-beam model

International Nuclear Information System (INIS)

Furman, M.A.

1989-05-01

We consider a simple one-dimensional model to study the effects of the beam-beam force on the coherent dynamics of colliding beams. The key ingredient is a linearized beam-beam kick. We study only the quadrupole modes, with the dynamical variables being the 2nd-order moments of the canonical variables q, p. Our model is self-consistent in the sense that no higher order moments are generated by the linearized beam-beam kicks, and that the only source of violation of symplecticity is the radiation. We discuss the round beam case only, in which vertical and horizontal quantities are assumed to be equal (though they may be different in the two beams). Depending on the values of the tune and beam intensity, we observe steady states in which otherwise identical bunches have sizes that are equal, or unequal, or periodic, or behave chaotically from turn to turn. Possible implications of luminosity saturation with increasing beam intensity are discussed. Finally, we present some preliminary applications to an asymmetric collider. 8 refs., 8 figs

Mechanical characteristics of ultra-long horizontal nanocantilevers grown by real-time feedback control on focused-ion-beam chemical vapour deposition

International Nuclear Information System (INIS)

Guo, Dengji; Warisawa, Shin’ichi; Ishihara, Sunao; Kometani, Reo

2015-01-01

Focused-ion-beam chemical vapour deposition (FIB-CVD) has been repeatedly proved to be a useful tool for the growth of three-dimensional (3D) micro- and nano-structures. The strategy of real-time feedback control on FIB-CVD was previously proposed and experimentally demonstrated to be effective for growing ultra-long horizontal nanocantilevers. To fabricate various nanoelectromechanical systems that consist of such types of nanocantilever structures, the mechanical characteristics of ultra-long horizontal nanocantilevers should be investigated. In this study, nanocantilevers with an overhang length of up to 35 μm were grown by using a 30 kV Ga + FIB, a beam current of 0.50 pA and phenanthrene (C 14 H 10 ) as the gas source to deposit a diamond-like carbon structure. The Young’s modulus of each nanocantilever was measured by bending the nanocantilever with a nanopillar whose Young’s modulus was known. The average density of each nanocantilever was calculated from the Young’s modulus and the measured resonant frequency. We found that the mechanical characteristics of each nanocantilever depended on the length of the nanocantilever if the strategy of real-time feedback control was applied in fabrication. The Young’s moduli and the averaged densities of the nanocantilevers with a length of 11 to 34 μm were found to be 86 to 254 GPa and 1950 to 5750 kg m −3 , respectively. With the increase of the overhang length, the Young’s modulus and the average density were found to gradually increase. (paper)

Status of neutron beam utilization at the Dalat nuclear research reactor

International Nuclear Information System (INIS)

Dien, Nguyen Nhi; Hai, Nguyen Canh

2003-01-01

The 500-kW Dalat nuclear research reactor was reconstructed from the USA-made 250-kW TRIGA Mark II reactor. After completion of renovation and upgrading, the reactor has been operating at its nominal power since 1984. The reactor is used mainly for radioisotope production, neutron activation analysis, neutron beam researches and reactor physics study. In the framework of the reconstruction and renovation project of the 1982-1984 period, the reactor core, the control and instrumentation system, the primary and secondary cooling systems, as well as other associated systems were newly designed and installed by the former Soviet Union. Some structures of the reactor, such as the reactor aluminum tank, the graphite reflector, the thermal column, horizontal beam tubes and the radiation concrete shielding have been remained from the previous TRIGA reactor. As a typical configuration of the TRIGA reactor, there are four neutron beam ports, including three radial and one tangential. Besides, there is a large thermal column. Until now only two-neutron beam ports and the thermal column have been utilized. Effective utilization of horizontal experimental channels is one of the important research objectives at the Dalat reactor. The research program on effective utilization of these experimental channels was conducted from 1984. For this purpose, investigations on physical characteristics of the reactor, neutron spectra and fluxes at these channels, safety conditions in their exploitation, etc. have been carried out. The neutron beams, however, have been used only since 1988. The filtered thermal neutron beams at the tangential channel have been extracted using a single crystal silicon filter and mainly used for prompt gamma neutron activation analysis (PGNAA), neutron radiography (NR) and transmission experiments (TE). The filtered quasi-monoenergetic keV neutron beams using neutron filters at the piercing channel have been used for nuclear data measurements, study on

Effects of parasitic beam-beam interaction during the injection process at the PEP-II B Factory

International Nuclear Information System (INIS)

Chin, Y.H.

1992-06-01

This paper is concerned with beam-beam effects during the injection process at the proposed asymmetric SLAC/LBL/LLNL B-Factory, PEP-II. It is shown that the parasitic beam-beam interaction can lead to a significant blowup in the vertical size of the injected beam. Simulation results for the horizontal and the vertical injection schemes are presented, and their performances are studied

Technical Note: On the impact of the incident electron beam energy on the primary dose component of flattening filter free photon beams.

Science.gov (United States)

Kuess, Peter; Georg, Dietmar; Palmans, Hugo; Lechner, Wolfgang

2016-08-01

For commercially available linear accelerators (Linacs), the electron energies of flattening filter free (FFF) and flattened (FF) beams are either identical or the electron energy of the FFF beam is increased to match the percentage depth dose curve (PDD) of the FF beam (in reference geometry). This study focuses on the primary dose components of FFF beams for both kinds of settings, studied on the same Linac. The measurements were conducted on a VersaHD Linac (Elekta, Crawley, UK) for both FF and FFF beams with nominal energies of 6 and 10 MV. In the clinical setting of the VersaHD, the energy of FFFM (Matched) beams is set to match the PDDs of the FF beams. In contrast the incident electron beam of the FFFU beam was set to the same energy as for the FF beam. Half value layers (HVLs) and a dual parameter beam quality specifier (DPBQS) were determined. For the 6 MV FFFM beam, HVL and DPBQS values were very similar compared to those of the 6 MV FF beam, while for the 10 MV FFFM and FF beams, only %dd(10)x and HVL values were comparable (differences below 1.5%). This shows that matching the PDD at one depth does not guarantee other beam quality dependent parameters to be matched. For FFFU beams, all investigated beam quality specifiers were significantly different compared to those for FF beams of the same nominal accelerator potential. The DPBQS of the 6 MV FF and FFFM beams was equal within the measurement uncertainty and was comparable to published data of a machine with similar TPR20,10 and %dd(10)x. In contrast to that, the DPBQS's two parameters of the 10 MV FFFM beam were substantially higher compared to those for the 10 MV FF beam. PDD-matched FF and FFF beams of both nominal accelerator potentials were observed to have similar HVL values, indicating similarity of their primary dose components. Using the DPBQS revealed that the mean attenuation coefficient was found to be the same within the uncertainty of 0.8% for 6 MV FF and 6 MV FFFM beams, while for 10 MV

Split core experiments; Part I. Axial neutron flux distribution measurements in the reactor core with a central horizontal reflector

Energy Technology Data Exchange (ETDEWEB)

Strugar, P; Raisic, N; Obradovic, D; Jovanovic, S [Institute of Nuclear Sciences Boris Kidric, Vinca, Beograd (Serbia and Montenegro)

1965-05-01

A series of critical experiments were performed on the RB reactor in order to determine the thermal neutron flux increase in the central horizontal reflector formed by a split reactor core. The objectives of these experiments were to study the possibilities of improving the thermal neutron flux characteristics of the neutron beam in the horizontal beam tube of the RA research reactor. The construction of RA reactor enables to split the core in two, to form a central horizontal reflector in front of the beam tube. This is achieved by replacing 2% enriched uranium slugs in the fuel channel by dummy aluminium slugs. The purpose of the first series of experiments was to study the gain in thermal neutron component inside the horizontal reflector and the loss of reactivity as a function of the lattice pitch and central reflector thickness.

LHC Report: First stable beams at 6.5 TeV

CERN Multimedia

Mike Lamont, Jorg Wenninger, Jan Uythoven, Stefano Redaelli, Wolfgang Hofle and Massimo Giovannozzi for the LHC team

2015-01-01

Give or take some important loose ends, the morning of Wednesday, 3 June saw the nominal end of an intense eight weeks of beam commissioning and the delivery of the first stable beams at 6.5 TeV. Under the gaze of the media, 3 nominal bunches per beam were taken through the full cycle into collisions. This was followed by the declaration of stable beams, marking the start of Run 2 physics data-taking.   The scenes in the CCC as stable beams at an energy of 6.5 TeV marked the start of run 2 physics at the LHC. The final stages of preparation involved the set-up of the tertiary collimators. These are situated on the incoming beam about 120 to 140 m from the interaction point where the beams are still in separate beam pipes. As the local orbit changes in this region during the squeeze and after the collapse of the separation bumps, the tertiary collimators set-up with respect to the beam is required both at the end of the squeeze and with colliding beams. The orbit and optics at the main collima...

Cryogenics system: strategy to achieve nominal performance and reliable operation

CERN Document Server

Bremer, J; Casas, J; Claudet, S; Delikaris, D; Delruelle, N; Ferlin, G; Fluder, C; Perin, A; Perinic, G; Pezzetti, M; Pirotte, O; Tavian, L; Wagner, U

2012-01-01

During the LHC operation in 2010 and 2011, the cryogenic system has achieved an availability level fulfilling the overall requirement. To reach this level, the cryogenic system has profited like many other beam-dependent systems from the reduced beam parameters. Therefore, impacts of some failures occurred during the LHC operation were mitigated by using the overcapacity margin, the existing built-in redundancy in between adjacent sector cryogenic plants and the "cannibalization" of spares on two idle cryogenic plants. These two first years of operation were also crucial to identify the weaknesses of the present cryogenic maintenance plan and new issues like SEUs. After the LS1, nominal beam parameters are expected and the mitigated measures will be less effective or not applicable at all. Consequently, a consolidation plan to improve the MTBF and the MTTR of the LHC cryogenic system is under definition. Concerning shutdown periods, the present cryogenic sectorization imposes some restrictions in the type of ...

Testing beam-induced quench levels of LHC superconducting magnets

Directory of Open Access Journals (Sweden)

B. Auchmann

2015-06-01

Full Text Available In the years 2009–2013 the Large Hadron Collider (LHC has been operated with the top beam energies of 3.5 and 4 TeV per proton (from 2012 instead of the nominal 7 TeV. The currents in the superconducting magnets were reduced accordingly. To date only seventeen beam-induced quenches have occurred; eight of them during specially designed quench tests, the others during injection. There has not been a single beam-induced quench during normal collider operation with stored beam. The conditions, however, are expected to become much more challenging after the long LHC shutdown. The magnets will be operating at near nominal currents, and in the presence of high energy and high intensity beams with a stored energy of up to 362 MJ per beam. In this paper we summarize our efforts to understand the quench levels of LHC superconducting magnets. We describe beam-loss events and dedicated experiments with beam, as well as the simulation methods used to reproduce the observable signals. The simulated energy deposition in the coils is compared to the quench levels predicted by electrothermal models, thus allowing one to validate and improve the models which are used to set beam-dump thresholds on beam-loss monitors for run 2.

Testing beam-induced quench levels of LHC superconducting magnets

Science.gov (United States)

Auchmann, B.; Baer, T.; Bednarek, M.; Bellodi, G.; Bracco, C.; Bruce, R.; Cerutti, F.; Chetvertkova, V.; Dehning, B.; Granieri, P. P.; Hofle, W.; Holzer, E. B.; Lechner, A.; Nebot Del Busto, E.; Priebe, A.; Redaelli, S.; Salvachua, B.; Sapinski, M.; Schmidt, R.; Shetty, N.; Skordis, E.; Solfaroli, M.; Steckert, J.; Valuch, D.; Verweij, A.; Wenninger, J.; Wollmann, D.; Zerlauth, M.

2015-06-01

In the years 2009-2013 the Large Hadron Collider (LHC) has been operated with the top beam energies of 3.5 and 4 TeV per proton (from 2012) instead of the nominal 7 TeV. The currents in the superconducting magnets were reduced accordingly. To date only seventeen beam-induced quenches have occurred; eight of them during specially designed quench tests, the others during injection. There has not been a single beam-induced quench during normal collider operation with stored beam. The conditions, however, are expected to become much more challenging after the long LHC shutdown. The magnets will be operating at near nominal currents, and in the presence of high energy and high intensity beams with a stored energy of up to 362 MJ per beam. In this paper we summarize our efforts to understand the quench levels of LHC superconducting magnets. We describe beam-loss events and dedicated experiments with beam, as well as the simulation methods used to reproduce the observable signals. The simulated energy deposition in the coils is compared to the quench levels predicted by electrothermal models, thus allowing one to validate and improve the models which are used to set beam-dump thresholds on beam-loss monitors for run 2.

Utilizations of filtered neutron beams at Dalat nuclear research reactor

International Nuclear Information System (INIS)

Hien, P.D.; Chau, L.N.; Tan, V.H.; Hiep, N.T.; Phuong, L.B.

1992-01-01

Neutron beam utilizations in basic and applied researches have been important activities at the Dalat nuclear reactor. The neutron filters with single crystal of silicon are used to produce thermal neutrons at the tangential horizontal channel and quasi-monoenergetic 144 KeV and 54 KeV neutrons at the piercing beam tube. The paper presents some relevant characteristics of the filtered neutron beams at the two horizontal channels. Applications of neutron beams in prompt gamma-ray activation analysis and in nuclear data measurements are briefly described. (author)

Beam profile effects on NPB [neutral particle beam] performance

International Nuclear Information System (INIS)

LeClaire, R.J. Jr.

1988-03-01

A comparison of neutral particle beam brightness for various neutral beam profiles indicates that the widely used assumption of a Gaussian profile may be misleading for collisional neutralizers. An analysis of available experimental evidence shows that lower peaks and higher tails, compared to a Gaussian beam profile, are observed out of collisional neutralizers, which implies that peak brightness is over estimated, and for a given NPB platform-to-target range, the beam current (power), dwell time or some combination of such engagement parameters would have to be altered to maintain a fixed dose on target. Based on the present analysis, this factor is nominally about 2.4 but may actually be as low as 1.8 or as high as 8. This is an important consideration in estimating NPB constellation performance in SDI engagement contexts. 2 refs., 6 figs

Simulation and Measurements of Beam Losses on LHC Collimators During Beam Abort Failures

CERN Document Server

Lari, L; Bruce, R; Goddard, B; Redaelli, S; Salvachua, B; Valentino, G; Faus-Golfe, A

2013-01-01

One of the main purposes of tracking simulations for collimation studies is to produce loss maps along the LHC ring, in order to identify the level of local beam losses during nominal and abnormal operation scenarios. The SixTrack program is the standard tracking tool used at CERN to perform these studies. Recently, it was expanded in order to evaluate the proton load on different collimators in case of fast beam failures. Simulations are compared with beam measurements at 4 TeV. Combined failures are assumed which provide worst-case scenarios of the load on tungsten tertiary collimators.

44 CFR 150.3 - Nomination process.

Science.gov (United States)

2010-10-01

... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Nomination process. 150.3 Section 150.3 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF... Nomination process. (a) The Nominating Officials nominating Firefighters and Civil Defense Officers shall...

Range of Possible Beam Current in Linac4

CERN Document Server

Lallement, J-B; CERN. Geneva. BE Department

2009-01-01

Linac4 is a new accelerator under construction at CERN. It is designed to accelerate H- ions to 160MeV, for injection into the existing Proton Synchrotron Booster (PSB). It is also the front-end of the SPL Linac, a high energy proton driver that will reach the energy of 5GeV. The Linac baseline design has been done for a nominal beam peak current of 70mA but it will certainly have to deal with different currents. 132 out of 155 quadrupoles in the Linac are permanent magnets, this choice of using PMQ having fixed gradient, mainly in the DTL and in the CCDTL may then entail issues concerning the beam transverse matching and quality from current different from the nominal one. In this paper, we present the beam dynamics performances in Linac4 obtained for different currents.

PBFA II lithium beam characterization from inner-shell x-ray images

International Nuclear Information System (INIS)

Moats, A.R.; Derzon, M.S.; Chandler, G.A.; Dukart, R.J.; Haill, T.A.

1994-01-01

The Particle Beam Fusion Accelerator (PBFA II) is not driving targets with ICF-relevant lithium ion beams. During the most recent lithium beam target series, time-integrated x-ray pinhole cameras viewed the ion-induced inner-shell x-ray fluorescence from the central gold cone target and a titanium-coated strip. Ion beam profiles at a nominal 10 mm radius and fixed azimuthal direction were obtained from images of the Ti K α , fluorescence of a Ti-coated Al diagnostic wire. The gold cone gave us beam profiles at a nominal 3 mm radius and at all azimuthal angles from the Au L α fluorescence. From these profiles, we obtained the ion beam vertical focus position, full-width-at-half-maximum, and the degree of azimuthal uniformity for the lithium target shots. For these initial results, beam steering problems were evident. Azimuthal uniformity was measured from the ion beam footprint on the outer Au case (predominantly Au L α ) of the hohlraum target and were found to be in the same range (up to 30%) as for previous proton beam target series. We then present plans for Li beam diagnostics for an upcoming target experimental series

7 CFR 1220.203 - Nominations.

Science.gov (United States)

2010-01-01

... CONSUMER INFORMATION Soybean Promotion and Research Order United Soybean Board § 1220.203 Nominations. All... be filled. (e) Nominations may be submitted in order of preference and for the initial Board, in order of preference for staggered terms. Should the Secretary reject any nomination submitted and there...

Technical Note: On the impact of the incident electron beam energy on the primary dose component of flattening filter free photon beams

International Nuclear Information System (INIS)

Kuess, Peter; Georg, Dietmar; Lechner, Wolfgang; Palmans, Hugo

2016-01-01

Purpose: For commercially available linear accelerators (Linacs), the electron energies of flattening filter free (FFF) and flattened (FF) beams are either identical or the electron energy of the FFF beam is increased to match the percentage depth dose curve (PDD) of the FF beam (in reference geometry). This study focuses on the primary dose components of FFF beams for both kinds of settings, studied on the same Linac. Methods: The measurements were conducted on a VersaHD Linac (Elekta, Crawley, UK) for both FF and FFF beams with nominal energies of 6 and 10 MV. In the clinical setting of the VersaHD, the energy of FFF M (Matched) beams is set to match the PDDs of the FF beams. In contrast the incident electron beam of the FFF U beam was set to the same energy as for the FF beam. Half value layers (HVLs) and a dual parameter beam quality specifier (DPBQS) were determined. Results: For the 6 MV FFF M beam, HVL and DPBQS values were very similar compared to those of the 6 MV FF beam, while for the 10 MV FFF M and FF beams, only %dd(10) x and HVL values were comparable (differences below 1.5%). This shows that matching the PDD at one depth does not guarantee other beam quality dependent parameters to be matched. For FFF U beams, all investigated beam quality specifiers were significantly different compared to those for FF beams of the same nominal accelerator potential. The DPBQS of the 6 MV FF and FFF M beams was equal within the measurement uncertainty and was comparable to published data of a machine with similar TPR 20,10 and %dd(10) x . In contrast to that, the DPBQS’s two parameters of the 10 MV FFF M beam were substantially higher compared to those for the 10 MV FF beam. Conclusions: PDD-matched FF and FFF beams of both nominal accelerator potentials were observed to have similar HVL values, indicating similarity of their primary dose components. Using the DPBQS revealed that the mean attenuation coefficient was found to be the same within the uncertainty of

Cherenkov Fibers for Beam Loss Monitoring at the CLIC Two Beam Module

CERN Document Server

van Hoorne, Jacobus Willem; Holzer, E B

The Compact Linear Collider (CLIC) study is a feasibility study aiming at a nominal center of mass energy of 3TeV and is based on normal conducting travelling-wave accelerating structures, operating at very high field gradients of 100 MV/m. Such high fields require high peak power and hence a novel power source, the CLIC two beam system, has been developed, in which a high intensity, low energy drive beam (DB) supplies energy to a high energy, low intensity main beam (MB). At the Two Beam Modules (TBM), which compose the 2x21km long CLIC main linac, a protection against beam losses resulting from badly controlled beams is necessary and particularly challenging, since the beam power of both main beam (14 MW) and drive beam (70 MW) is impressive. To avoid operational downtimes and severe damages to machine components, a general Machine Protection System (MPS) scheme has been developed. The Beam Loss Monitoring (BLM) system is a key element of the CLIC machine protection system. Its main role will be to detect p...

Horizontal-view interferometer on TEXT-Upgrade

International Nuclear Information System (INIS)

Jiang, Y.; Brower, D.L.

1994-01-01

The first experimental results from the horizontal-view, multichannel, heterodyne FIR interferometer system on TEXT-Upgrade are reported. The system employs parabolic beam-expansion optics and a 15 cm array with minimum channel spacing of 1.5 cm. Profiles of the plasma electron density will be presented. In addition, small-amplitude density perturbations resulting from sawteeth and tearing modes are examined. Due to the double-pass of the laser beam through the plasma and the large distance of the detector array [2.5 m] from the plasma, refractive effects must be addressed for densities greater than 2 x 10 13 cm -3 . A ray tracing code is developed to correct the measured profiles

Evolution of hadron beams under intrabeam scattering

International Nuclear Information System (INIS)

Wei, Jie.

1993-01-01

Based on assumptions applicable to many circular accelerators, we simplify into analytical form the growth rates of a hadron beam under Coulomb intrabeam scattering (IBS). Because of the dispersion that correlates the horizontal closed orbit to the momentum, the scaling behavior of the growth rates are drastically different at energies low and high compared with the transition energy. At high energies the rates are approximately independent of the energy. Asymptotically, the horizontal and longitudinal beam amplitudes are linearly related by the average dispersion. At low energies, the beam evolves such that the velocity distribution in the rest frame becomes isotropic in all the directions

Beams dynamics optimisation of LINAC4 structures for increased operational flexibility

CERN Document Server

Bellodi, G; Garcia Tudela, M; Hein, L M; Lallement, J B; Lombardi, A M; Posocco, P A; Sargsyan, E; Stovall, J

2010-01-01

Linac4 is a new 160 MeV, 40 mA pulsed beam current H- accelerator which will be the source of particles for all proton accelerators at CERN. Construction started in October 2008, and beam commissioning of the 3 MeV front-end is scheduled for early next year. A baseline design of the linac beam dynamics was completed 2 years ago and validated by a systematic campaign of transverse and longitudinal error studies to assess tolerance limits and machine activation levels. Recent studies have been mainly focused on optimising this design to achieve both a smoother performance for nominal beam conditions and to gain operational flexibility for non-nominal scenarios. These include a review of the chopper beam dynamics design, a re-definition of the DTL and CCDTL inter-tank regions and a study of operational schemes for reduced beam currents (either permanent or in pulse-to-pulse mode). These studies have been carried out in parallel to first specifications for a beam commissioning strategy of the linac and its low-en...

Reliability Analysis of the new Link between the Beam Interlock System and the LHC Beam Dumping System Zuverlässigkeitsanalyse der neuen Verbindung zwischen dem Beam Interlock System und dem LHC Beam Dumping System

CERN Document Server

Vatansever, Volkan

The nominal stored energy in each LHC beam is 360 MJ, surpassing the beam energy of other accelerators by orders of magnitude. This energy threatens to damage accelerator components in case of uncontrolled beam losses To avoid damage of accelerator equipment due to impacting beam, the controlled removal of the LHC beams from the collider rings towards the dump block must be guaranteed at all times. Therefore, the LHC Beam Dumping System was built according to high reliability standards. To further reduce the risk of incapability to dump the beams in case of correlated failures in the redundant system, a new direct link from the LHC Beam Interlock System to the Re-triggering Lines of the LHC Beam Dumping System will be implemented for the startup with beam in 2015. This link represents a diverse redundancy to the current implementation, which should neither significantly increase the risk for so-called Asynchronous Beam Dumps nor compromise machine availability. Therefore, a reliability analysis down to the co...

Reble, a radially converging electron beam accelerator

International Nuclear Information System (INIS)

Ramirez, J.J.; Prestwich, K.R.

1976-01-01

The Reble accelerator at Sandia Laboratories is described. This accelerator was developed to provide an experimental source for studying the relevant diode physics, beam propagation, beam energy deposition in a gas using a radially converging e-beam. The nominal parameters for Reble are 1 MV, 200 kA, 20 ns e-beam pulse. The anode and cathode are concentric cylinders with the anode as the inner cylinder. The radial beam can be propagated through the thin foil anode into the laser gas volume. The design and performance of the various components of the accelerator are presented

MIPAS-ENVISAT limb-sounding measurements: trade-off study for improvement of horizontal resolution.

Science.gov (United States)

Ridolfi, Marco; Magnani, Luca; Carlotti, Massimo; Dinelli, Bianca Maria

2004-11-01

The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) is a limb-scanning spectrometer that has operated onboard the Environmental Satellite since the end of March 2002. Common features of limb-scanning experiments are both high vertical resolution and poor horizontal resolution. We exploit the two-dimensional geo-fit retrieval approach [Appl. Opt. 40, 1872-1875 (2001)] to investigate the possibility of improving the horizontal resolution of MIPAS measurements. Two different strategies are considered for this purpose, one exploiting the possibility (offered by the geo-fit analysis method) for an arbitrary definition of the retrieval grid, the other based on the possibility of saving measurement time by degrading the spectral resolution of the interferometer. The performances of the two strategies are compared in terms of the trade-off between the attained horizontal resolution and the retrieval precision. We find that for ozone it is possible to improve by a factor of 2 the horizontal resolution, which in the nominal measurement plan is approximately 530 km. This improvement corresponds to a degradation of the retrieval precision, which on average varies from a factor of 1.4 to 2.5, depending on the adopted spectral resolution.

Implementation and operation of methane plant in Belo Horizonte; Implantacao e operacao da usina de metano de Belo Horizonte

Energy Technology Data Exchange (ETDEWEB)

Loiola, A.V. de; Costa Ribeiro, M.D.B. [Companhia Energetica de Minas Gerais (CEMIG), Belo Horizonte, MG (Brazil)

1990-12-31

The volume of trash deposited on the Belo Horizonte landfill (Southeast Brazil) is 500 ton per day. The organic material contained in this urban residues undergoes an aerobic decomposition, generating the raw biogas. For the utilization of this source of energy, which combustion releases non toxic and non polluted products, a collection, depuration, and compression systems have been built, with a nominal production capacity of 400 Nm{sup 3} per hour of purified biogas. The obtained experience in the plant implementation and pre-operation have permitted the development of new kinds of collection wells, new ways of sealing landfill areas, and the adaptation of national equipment for the operational conditions of the depuration system. 1 ref., 2 figs., 1 tab

Analytic reconstruction algorithms for triple-source CT with horizontal data truncation

International Nuclear Information System (INIS)

Chen, Ming; Yu, Hengyong

2015-01-01

Purpose: This paper explores a triple-source imaging method with horizontal data truncation to enlarge the field of view (FOV) for big objects. Methods: The study is conducted by using theoretical analysis, mathematical deduction, and numerical simulations. The proposed algorithms are implemented in c + + and MATLAB. While the basic platform is constructed in MATLAB, the computationally intensive segments are coded in c + +, which are linked via a MEX interface. Results: A triple-source circular scanning configuration with horizontal data truncation is developed, where three pairs of x-ray sources and detectors are unevenly distributed on the same circle to cover the whole imaging object. For this triple-source configuration, a fan-beam filtered backprojection-type algorithm is derived for truncated full-scan projections without data rebinning. The algorithm is also extended for horizontally truncated half-scan projections and cone-beam projections in a Feldkamp-type framework. Using their method, the FOV is enlarged twofold to threefold to scan bigger objects with high speed and quality. The numerical simulation results confirm the correctness and effectiveness of the developed algorithms. Conclusions: The triple-source scanning configuration with horizontal data truncation cannot only keep most of the advantages of a traditional multisource system but also cover a larger FOV for big imaging objects. In addition, because the filtering is shift-invariant, the proposed algorithms are very fast and easily parallelized on graphic processing units

Flattening filter free beams from TrueBeam and Versa HD units: Evaluation of the parameters for quality assurance

Energy Technology Data Exchange (ETDEWEB)

Fogliata, Antonella, E-mail: antonella.fogliata@humanitas.it; Reggiori, Giacomo; Stravato, Antonella; Scorsetti, Marta; Cozzi, Luca [Radiotherapy and Radiosurgery Department, Humanitas Research Hospital, Milan-Rozzano I-20098 (Italy); Fleckenstein, Jens; Schneider, Frank; Lohr, Frank [Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Mannheim D-68167 (Germany); Pachoud, Marc; Ghandour, Sarah [Radiation Oncology Department, Hôpital Riviera Chablais, Vevey CH-1800 (Switzerland); Krauss, Harald [Radio-Oncology Department, Kaiser Franz Josef Spital, Vienna A-1100 (Austria)

2016-01-15

Purpose: Flattening filter free (FFF) beams generated by medical linear accelerators are today clinically used for stereotactical and non-stereotactical radiotherapy treatments. Such beams differ from the standard flattened beams (FF) in the high dose rate and the profile shape peaked on the beam central axis. Definition of new parameters as unflatness and slope for FFF beams has been proposed based on a renormalization factor for FFF profiles. The present study aims to assess the dosimetric differences between FFF beams generated by linear accelerators from different vendors, and to provide renormalization and parameter data of the two kinds of units. Methods: Dosimetric data from two Varian TrueBeam and two Elekta Versa HD linear accelerators, all with 6 and 10 MV nominal accelerating potentials, FF and FFF modes have been collected. Renormalization factors and related fit parameters according to Fogliata et al. [“Definition of parameters for quality assurance of flattening filter free (FFF) photon beams in radiation therapy,” Med. Phys. 39, 6455–6464 (2012)] have been evaluated for FFF beams of both units and energies. Unflatness and slope parameters from profile curves were evaluated. Dosimetric differences in terms of beam penetration and near-the-surface dose were also assessed. Results: FFF profile parameters have been updated; renormalization factors and unflatness from the Varian units are consistent with the published data. Elekta FFF beam qualities, different from the Varian generated beams, tend to express similar behaviour as the FF beam of the corresponding nominal energy. TPR{sub 20,10} for 6 and 10 MV FF and FFF TrueBeam beams are 0.665, 0.629 (6 MV) and 0.738, 0.703 (10 MV). The same figures for Versa HD units are 0.684, 0.678 (6 MV) and 0.734, 0.721 (10 MV). Conclusions: Renormalization factor and unflatness parameters evaluated from Varian and Elekta FFF beams are provided, in particular renormalization factors table and fit parameters.

End to End Beam Dynamics of the ESS Linac

DEFF Research Database (Denmark)

Thomsen, Heine Dølrath

2012-01-01

The European Spallation Source, ESS, uses a linear accelerator to deliver a high intensity proton beam to the target station. The nominal beam power on target will be 5 MW at an energy of 2.5 GeV. We briefly describe the individual accelerating structures and transport lines through which we have...

Flat beams in the SLC

International Nuclear Information System (INIS)

Adolphsen, C.; Barklow, T.; Burke, D.; Decker, F.J.; Emma, P.; Hildreth, M.; Himel, T.; Krejcik, P.; Limberg, T.; Minty, M.

1993-01-01

The Stanford Linear Collider was designed to operate with round beams; horizontal and vertical emittance made equal in the damping rings. The main motivation was to facilitate the optical matching through beam lines with strong coupling elements like the solenoid spin rotator magnets and the SLC arcs. Tests in 1992 showed that open-quote flat close-quote beams with a vertical to horizontal emittance ratio of around 1/10 can be successfully delivered to the end of the linac. Techniques developed to measure and control the coupling of the SLC arcs allow These beams to be transported to the Interaction Point (IP). Before flat beams could be used for collisions with polarized electrons, a new method of rotating the electron spin orientation with vertical arc orbit bumps had to be developed. Early in the 1993 run, the SLC was switched to open-quote flat close-quote beam operation. Within a short time the peak luminosity of the previous running cycle was reached and then surpassed. The average daily luminosity is now a factor of about two higher than the best achieved last year. In the following the authors present an overview of the problems encountered and their solutions for different parts of the SLC

Characterisation of the Muon Beams for the Muon Ionisation Cooling Experiment

CERN Document Server

Adams, D.; Alekou, A.; Apollonio, M.; Asfandiyarov, R.; Back, J.; Barber, G.; Barclay, P.; de Bari, A.; Bayes, R.; Bayliss, V.; Bertoni, R.; Blackmore, V.J.; Blondel, A.; Blot, S.; Bogomilov, M.; Bonesini, M.; Booth, C.N.; Bowring, D.; Boyd, S.; Bradshaw, T.W.; Bravar, U.; Bross, A.D.; Capponi, M.; Carlisle, T.; Cecchet, G.; Charnley, G.; Cobb, J.H.; Colling, D.; Collomb, N.; Coney, L.; Cooke, P.; Courthold, M.; Cremaldi, L.M.; DeMello, A.; Dick, A.; Dobbs, A.; Dornan, P.; Fayer, S.; Filthaut, F.; Fish, A.; Fitzpatrick, T.; Fletcher, R.; Forrest, D.; Francis, V.; Freemire, B.; Fry, L.; Gallagher, A.; Gamet, R.; Gourlay, S.; Grant, A.; Graulich, J.S.; Griffiths, S.; Hanlet, P.; Hansen, O.M.; Hanson, G.G.; Harrison, P.; Hart, T.L.; Hartnett, T.; Hayler, T.; Heidt, C.; Hills, M.; Hodgson, P.; Iaciofano, A.; Ishimoto, S.; Kafka, G.; Kaplan, D.M.; Karadzhov, Y.; Kim, Y.K.; Kolev, D.; Kuno, Y.; Kyberd, P.; Lau, W.; Leaver, J.; Leonova, M.; Li, D.; Lintern, A.; Littlefield, M.; Long, K.; Lucchini, G.; Luo, T.; Macwaters, C.; Martlew, B.; Martyniak, J.; Middleton, S.; Moretti, A.; Moss, A.; Muir, A.; Mullacrane, I.; Nebrensky, J.J.; Neuffer, D.; Nichols, A.; Nicholson, R.; Nugent, J.C.; Onel, Y.; Orestano, D.; Overton, E.; Owens, P.; Palladino, V.; Palmer, R.B.; Pasternak, J.; Pastore, F.; Pidcott, C.; Popovic, M.; Preece, R.; Prestemon, S.; Rajaram, D.; Ramberger, S.; Rayner, M.A.; Ricciardi, S.; Richards, A.; Roberts, T.J.; Robinson, M.; Rogers, C.; Ronald, K.; Rubinov, P.; Rucinski, R.; Rusinov, I.; Sakamoto, H.; Sanders, D.A.; Santos, E.; Savidge, T.; Smith, P.J.; Snopok, P.; Soler, F.J.P.; Stanley, T.; Summers, D.J.; Takahashi, M.; Tarrant, J.; Taylor, I.; Tortora, L.; Torun, Y.; Tsenov, R.; Tunnell, C.D.; Vankova, G.; Verguilov, V.; Virostek, S.; Vretenar, M.; Walaron, K.; Watson, S.; White, C.; Whyte, C.G.; Wilson, A.; Wisting, H.; Zisman, M.

2013-01-01

A novel single-particle technique to measure emittance has been developed and used to characterise seventeen different muon beams for the Muon Ionisation Cooling Experiment (MICE). The muon beams, whose mean momenta vary from 171 to 281 MeV/c, have emittances of approximately 1.5--2.3 \\pi mm-rad horizontally and 0.6--1.0 \\pi mm-rad vertically, a horizontal dispersion of 90--190 mm and momentum spreads of about 25 MeV/c. There is reasonable agreement between the measured parameters of the beams and the results of simulations. The beams are found to meet the requirements of MICE.

Characterisation of the muon beams for the Muon Ionisation Cooling Experiment

Energy Technology Data Exchange (ETDEWEB)

Adams, D.; et al.,

2013-10-01

A novel single-particle technique to measure emittance has been developed and used to characterise seventeen different muon beams for the Muon Ionisation Cooling Experiment (MICE). The muon beams, whose mean momenta vary from 171 to 281 MeV/c, have emittances of approximately 1.5--2.3 \\pi mm-rad horizontally and 0.6--1.0 \\pi mm-rad vertically, a horizontal dispersion of 90--190 mm and momentum spreads of about 25 MeV/c. There is reasonable agreement between the measured parameters of the beams and the results of simulations. The beams are found to meet the requirements of MICE.

Determinants of nomination committee: New Zealand evidence

Directory of Open Access Journals (Sweden)

Md. Borhan Uddin Bhuiyan

2011-09-01

Full Text Available A sizable volume of corporate governance literature documents that an independent and competent board of directors matter for organizational success. In order to function effectively, board comprises of different sub-committees and the three most common sub-committees are audit committees, compensation committees and nomination committees. Surprisingly, there is a paucity of research in understanding the determinants of nomination committee notwithstanding the importance of an independent nomination committee in board selection process. We contribute to the nomination committee literature by investigating the factors associated with the determination of nomination committees in New Zealand. We find that cross-sectional variation in the firm-specific characteristics affect the existence of nomination committees. This finding casts doubt on the „one-size-fits all‟ approach of corporate governance. Our logistic regression of the nomination committee determinants indicates that firm size, governance regulation and busy directors are positively associated with the existence of nomination committees, whereas firm leverage, controlling shareholders, and director independence are negatively related to the formation of nomination committees.

Nominate an Organization | Distributed Generation Interconnection

Science.gov (United States)

Collaborative | NREL Nominate an Organization Nominate an Organization Do you know of an organization doing high-quality, innovative work on the interconnection of distributed generation? Want to practices by nominating an organization to be profiled in an online case study! Please include your

Growth of high-aspect ratio horizontally-aligned ZnO nanowire arrays.

Science.gov (United States)

Soman, Pranav; Darnell, Max; Feldman, Marc D; Chen, Shaochen

2011-08-01

A method of fabricating horizontally-aligned zinc-oxide (ZnO) nanowire (NW) arrays with full control over the width and length is demonstrated. SEM images reveal the hexagonal structure typical of zinc oxide NWs. Arrays of high-aspect ratio horizontal ZnO NWs are fabricated by making use of the lateral overgrowth from dot patterns created by electron beam lithography (EBL). An array of patterned wires are lifted off and transferred to a flexible PDMS substrate with possible applications in several key nanotechnology areas.

Horizontal maps of echo power in the lower stratosphere using the MU radar

Directory of Open Access Journals (Sweden)

M. Hirono

2004-03-01

Full Text Available In recent works, zenithal and azimuthal angle variations of echo power measured by VHF Stratosphere-Troposphere (ST radars have been analyzed in detail using different radar multi-beam configurations. It was found that the azimuthal angle corresponding to maximum echo power is closely related to the direction of the horizontal wind shear. These properties indicate that local wind shear affects the tilt of the scatterers. Moreover, horizontal maps of echo power collected using a large set of beams steered pulse-to-pulse up to 40 degrees off zenith revealed that the power distribution pattern in the troposphere is often skewed. In this work, a three-dimensional description of echo power variations up to 24 degrees off zenith is shown for measurements in the lower stratosphere (i.e. up to approximately 20km using a "sequential multi-beam" (SMB configuration. Such a description was not possible above the tropopause with classical multi-beam configurations because of the loss of radar sensitivity due to the limited integration time by the use of a large number of beams. This work attempts to complete previous descriptions of the phenomenon by some observations in the lower stratosphere discussed in association with complementary balloon measurements. Key words. Meteorology and atmospheric dynamics (turbulence – Radio Science (remote sensing

The nominalized infinitive in French : structure and change

Directory of Open Access Journals (Sweden)

Petra Sleeman

2010-01-01

Full Text Available Many European languages have both nominal and verbal nominalized infinitives. They differ, however, in the degree to which the nominalized infinitives possess nominal and verbal properties. In this paper, nominalized infinitives in French are analyzed. It is shown that, whereas Old French was like other Romance languages in possessing both nominal and verbal nominalized infinitives, Modern French differs parametrically from other Romance languages in not having verbal infinitives and in allowing nominal infinitives only in a scientific style of speech. An analysis is proposed, within a syntactic approach to morphology. that tries to account for the loss of the verbal properties of the nominalized infinitive in French. It is proposed that the loss results from a change in word order (the loss of the OV word order in favor of the VO word order and a change in the morphological analysis of the nominalized infinitive: instead of a zero suffix analysis, a derivational analysis was adopted by the speakers of French. It is argued that the derivational analysis restricted nominalization to Vo, which made nominalization of infinitives less ìverbalî than in other Romance languages

Monte Carlo simulation of beam characteristics from small fields based on TrueBeam flattening-filter-free mode

International Nuclear Information System (INIS)

Feng, Zhongsu; Yue, Haizhen; Zhang, Yibao; Wu, Hao; Cheng, Jinsheng; Su, Xu

2016-01-01

Through the Monte Carlo (MC) simulation of 6 and 10 MV flattening-filter-free (FFF) beams from Varian TrueBeam accelerator, this study aims to find the best incident electron distribution for further studying the small field characteristics of these beams. By incorporating the training materials of Varian on the geometry and material parameters of TrueBeam Linac head, the 6 and 10 MV FFF beams were modelled using the BEAMnrc and DOSXYZnrc codes, where the percentage depth doses (PDDs) and the off-axis ratios (OARs) curves of fields ranging from 4 × 4 to 40 × 40 cm 2 were simulated for both energies by adjusting the incident beam energy, radial intensity distribution and angular spread, respectively. The beam quality and relative output factor (ROF) were calculated. The simulations and measurements were compared using Gamma analysis method provided by Verisoft program (PTW, Freiburg, Germany), based on which the optimal MC model input parameters were selected and were further used to investigate the beam characteristics of small fields. The Full Width Half Maximum (FWHM), mono-energetic energy and angular spread of the resultant incident Gaussian radial intensity electron distribution were 0.75 mm, 6.1 MeV and 0.9° for the nominal 6 MV FFF beam, and 0.7 mm, 10.8 MeV and 0.3° for the nominal 10 MV FFF beam respectively. The simulation was mostly comparable to the measurement. Gamma criteria of 1 mm/1 % (local dose) can be met by all PDDs of fields larger than 1 × 1 cm 2 , and by all OARs of no larger than 20 × 20 cm 2 , otherwise criteria of 1 mm/2 % can be fulfilled. Our MC simulated ROFs agreed well with the measured ROFs of various field sizes (the discrepancies were less than 1 %), except for the 1 × 1 cm 2 field. The MC simulation agrees well with the measurement and the proposed model parameters can be clinically used for further dosimetric studies of 6 and 10 MV FFF beams

Characterisation of the muon beams for the Muon Ionisation Cooling Experiment

Energy Technology Data Exchange (ETDEWEB)

Adams, D.; Barclay, P.; Bayliss, V.; Bradshaw, T.W.; Courthold, M.; Francis, V.; Fry, L.; Hayler, T.; Hills, M.; Lintern, A.; Macwaters, C.; Nichols, A.; Preece, R.; Ricciardi, S.; Rogers, C.; Stanley, T.; Tarrant, J.; Watson, S.; Wilson, A. [Harwell Oxford, STFC Rutherford Appleton Laboratory, Didcot (United Kingdom); Adey, D.; Back, J.; Boyd, S.; Harrison, P.; Pidcott, C.; Taylor, I. [University of Warwick, Department of Physics, Coventry (United Kingdom); Alekou, A.; Apollonio, M.; Barber, G.; Colling, D.; Dobbs, A.; Dornan, P.; Fayer, S.; Fish, A.; Hunt, C.; Leaver, J.; Long, K.; Martyniak, J.; Middleton, S.; Pasternak, J.; Richards, A.; Santos, E.; Savidge, T.; Takahashi, M. [Imperial College London, Department of Physics, Blackett Laboratory, London (United Kingdom); Asfandiyarov, R.; Blondel, A.; Graulich, J.S.; Karadzhov, Y.; Verguilov, V.; Wisting, H. [Universite de Geneve, DPNC, Section de Physique, Geneva (Switzerland); De Bari, A.; Cecchet, G. [Sezione INFN Pavia (Italy); Dipartimento di Fisica Nucleare e Teorica, Pavia (Italy); Bayes, R.; Forrest, D.; Nugent, J.C.; Soler, F.J.P.; Walaron, K. [The University of Glasgow, School of Physics and Astronomy, Glasgow (United Kingdom); Bertoni, R.; Bonesini, M.; Lucchini, G. [Sezione INFN Milano Bicocca (Italy); Dipartimento di Fisica G. Occhialini, Milano (Italy); Blackmore, V.J.; Carlisle, T.; Cobb, J.H.; Lau, W.; Rayner, M.A.; Tunnell, C.D. [University of Oxford, Department of Physics, Oxford (United Kingdom); Blot, S.; Kim, Y.K. [University of Chicago, Enrico Fermi Institute, Chicago, IL (United States); Bogomilov, M.; Kolev, D.; Rusinov, I.; Tsenov, R.; Vankova, G. [St. Kliment Ohridski University of Sofia, Department of Atomic Physics, Sofia (Bulgaria); Booth, C.N.; Hodgson, P.; Nicholson, R.; Overton, E.; Robinson, M.; Smith, P.J. [University of Sheffield, Department of Physics and Astronomy, Sheffield (United Kingdom); Bowring, D.; DeMello, A.; Gourlay, S.; Li, D.; Prestemon, S.; Virostek, S.P.; Zisman, M.S. [Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Bravar, U. [University of New Hampshire, Durham, NH (United States); Bross, A.D.; Fitzpatrick, T.; Leonova, M.; Moretti, A.; Neuffer, D.; Popovic, M.; Rubinov, P.; Rucinski, R. [Fermilab, Batavia, IL (United States); Capponi, M.; Iaciofano, A.; Orestano, D.; Pastore, F.; Tortora, L. [Sezione INFN Roma Tre e Dipartimento di Fisica, Roma (Italy); Charnley, G.; Collomb, N.; Gallagher, A.; Grant, A.; Griffiths, S.; Hartnett, T.; Martlew, B.; Moss, A.; Muir, A.; Mullacrane, I.; Owens, P.; White, C. [STFC Daresbury Laboratory, Cheshire (United Kingdom); Coney, L.; Fletcher, R.; Hanson, G.G.; Heidt, C. [University of California, Riverside, CA (United States); Cooke, P.; Gamet, R. [University of Liverpool, Department of Physics, Liverpool (United Kingdom); Cremaldi, L.M.; Hart, T.L.; Luo, T.; Sanders, D.A.; Summers, D.J. [University of Mississippi, Oxford, MS (United States); Dick, A.J.; Ronald, K.; Whyte, C.G. [University of Strathclyde, Department of Physics, Glasgow (United Kingdom); Filthaut, F. [NIKHEF, Amsterdam (Netherlands); Freemire, B.; Hanlet, P.; Kafka, G.; Kaplan, D.M.; Rajaram, D.; Snopok, P.; Torun, Y. [Illinois Institute of Technology, Chicago, IL (United States); Hansen, O.M.; Ramberger, S.; Vretenar, M. [CERN, Geneva (Switzerland); Ishimoto, S. [Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki (Japan); Kuno, Y.; Sakamoto, H. [Osaka University, Graduate School of Science, Department of Physics, Toyonaka, Osaka (Japan); Kyberd, P.; Littlefield, M.; Nebrensky, J.J. [Brunel University, Uxbridge (United Kingdom); Onel, Y. [University of Iowa, Department of Physics and Astronomy, Iowa City, IA (United States); Palladino, V. [Universita Federico II, Sezione INFN Napoli (Italy); Dipartimento di Fisica, Napoli (Italy); Palmer, R.B. [Brookhaven National Laboratory, Upton, NY (US); Roberts, T.J. [Muons, Inc., Batavia, IL (US); Collaboration: The MICE Collaboration

2013-10-15

A novel single-particle technique to measure emittance has been developed and used to characterise seventeen different muon beams for the Muon Ionisation Cooling Experiment (MICE). The muon beams, whose mean momenta vary from 171 to 281 MeV/c, have emittances of approximately 1.2-2.3 {pi} mm-rad horizontally and 0.6-1.0 {pi} mm-rad vertically, a horizontal dispersion of 90-190 mm and momentum spreads of about 25 MeV/c. There is reasonable agreement between the measured parameters of the beams and the results of simulations. The beams are found to meet the requirements of MICE. (orig.)

Characterisation of the muon beams for the Muon Ionisation Cooling Experiment

International Nuclear Information System (INIS)

Adams, D.; Barclay, P.; Bayliss, V.; Bradshaw, T.W.; Courthold, M.; Francis, V.; Fry, L.; Hayler, T.; Hills, M.; Lintern, A.; Macwaters, C.; Nichols, A.; Preece, R.; Ricciardi, S.; Rogers, C.; Stanley, T.; Tarrant, J.; Watson, S.; Wilson, A.; Adey, D.; Back, J.; Boyd, S.; Harrison, P.; Pidcott, C.; Taylor, I.; Alekou, A.; Apollonio, M.; Barber, G.; Colling, D.; Dobbs, A.; Dornan, P.; Fayer, S.; Fish, A.; Hunt, C.; Leaver, J.; Long, K.; Martyniak, J.; Middleton, S.; Pasternak, J.; Richards, A.; Santos, E.; Savidge, T.; Takahashi, M.; Asfandiyarov, R.; Blondel, A.; Graulich, J.S.; Karadzhov, Y.; Verguilov, V.; Wisting, H.; De Bari, A.; Cecchet, G.; Bayes, R.; Forrest, D.; Nugent, J.C.; Soler, F.J.P.; Walaron, K.; Bertoni, R.; Bonesini, M.; Lucchini, G.; Blackmore, V.J.; Carlisle, T.; Cobb, J.H.; Lau, W.; Rayner, M.A.; Tunnell, C.D.; Blot, S.; Kim, Y.K.; Bogomilov, M.; Kolev, D.; Rusinov, I.; Tsenov, R.; Vankova, G.; Booth, C.N.; Hodgson, P.; Nicholson, R.; Overton, E.; Robinson, M.; Smith, P.J.; Bowring, D.; DeMello, A.; Gourlay, S.; Li, D.; Prestemon, S.; Virostek, S.P.; Zisman, M.S.; Bravar, U.; Bross, A.D.; Fitzpatrick, T.; Leonova, M.; Moretti, A.; Neuffer, D.; Popovic, M.; Rubinov, P.; Rucinski, R.; Capponi, M.; Iaciofano, A.; Orestano, D.; Pastore, F.; Tortora, L.; Charnley, G.; Collomb, N.; Gallagher, A.; Grant, A.; Griffiths, S.; Hartnett, T.; Martlew, B.; Moss, A.; Muir, A.; Mullacrane, I.; Owens, P.; White, C.; Coney, L.; Fletcher, R.; Hanson, G.G.; Heidt, C.; Cooke, P.; Gamet, R.; Cremaldi, L.M.; Hart, T.L.; Luo, T.; Sanders, D.A.; Summers, D.J.; Dick, A.J.; Ronald, K.; Whyte, C.G.; Filthaut, F.; Freemire, B.; Hanlet, P.; Kafka, G.; Kaplan, D.M.; Rajaram, D.; Snopok, P.; Torun, Y.; Hansen, O.M.; Ramberger, S.; Vretenar, M.; Ishimoto, S.; Kuno, Y.; Sakamoto, H.; Kyberd, P.; Littlefield, M.; Nebrensky, J.J.; Onel, Y.; Palladino, V.; Palmer, R.B.; Roberts, T.J.

2013-01-01

A novel single-particle technique to measure emittance has been developed and used to characterise seventeen different muon beams for the Muon Ionisation Cooling Experiment (MICE). The muon beams, whose mean momenta vary from 171 to 281 MeV/c, have emittances of approximately 1.2-2.3 π mm-rad horizontally and 0.6-1.0 π mm-rad vertically, a horizontal dispersion of 90-190 mm and momentum spreads of about 25 MeV/c. There is reasonable agreement between the measured parameters of the beams and the results of simulations. The beams are found to meet the requirements of MICE. (orig.)

Preliminary analysis of beam trip and beam jump events in an ADS prototype

International Nuclear Information System (INIS)

D'Angelo, A.; Bianchini, G.; Carta, M.

2001-01-01

A core dynamics analysis relevant to some typical current transient events has been carried out on an 80 MW energy amplifier prototype (EAP) fuelled by mixed oxides and cooled by lead-bismuth. Fuel and coolant temperature trends relevant to recovered beam trip and beam jump events have been preliminary investigated. Beam trip results show that the drop in temperature of the core outlet coolant would be reduced a fair amount if the beam intensity could be recovered within few seconds. Due to the low power density in the EAP fuel, the beam jump from 50% of the nominal power transient evolves benignly. The worst thinkable current transient, beam jump with cold reactor, mainly depends on the coolant flow conditions. In the EAP design, the primary loop coolant flow is assured by natural convection and is enhanced by a particular system of cover gas injection into the bottom part of the riser. If this system of coolant flow enhancement is assumed in function, even the beam jump with cold reactor event evolves without severe consequences. (authors)

Characteristics of photon beams from Philips SL25 linear accelerators

International Nuclear Information System (INIS)

Palta, J.R.; Ayyangar, K.; Daftari, I.; Suntharalingam, N.

1990-01-01

The Philips SL25 accelerator is a multimodality machine offering asymmetric collimator jaws and a new type of beam bending and transport system. It produces photon beams, nominally at 6 and 25 MV, and a scattered electron beam with nine selectable energies between 4 and 22 MeV. Dosimetric characteristics for the 6- and 25-MV photon beams are presented with respect to field flatness, surface and depth dose characteristics, isodose distribution, field size factors for both open and wedged fields, and narrow beam transmission data in different materials

Parametric motivation bases of floranimic nomination

Directory of Open Access Journals (Sweden)

Olga P. Ryabko

2016-09-01

Full Text Available The period of further development in the cognitive theory of nomination has been extensive in recent years. Our research has been concentrated on the formation of conceptual foundations in cognitive theory of flora nomination. The macrofield of flora namings embraces three microfields: parametric, pragmatic and locative-temporal ones. They determine motivation processes in cognitive theory of flora nomination, i.e., the presentation of systematic qualities in flora namings in the English language. The description and characterization of such qualities presupposes the existence of their taxonomic organization and methodology criteria, both general and practical ones. Flora namings on the phenomenological level are considered to be the products of naöve-cognitive consciousness of language speakers. They are determined, from the one hand, by the external perceptive adaptations (parametric nomination and, from the other hand, by practical needs (pure pragmatic nomination and local-temporal nomination. In this article we have concentrated on the complex parametric motivated basis of flora nomination. It is presented by a number of qualities, firstly, by dominative qualities («form», «appearance and manner of growth», «color», secondly, by peripheral qualities («odour», «taste», «size» and, finally, by minor qualities («sound», «weight», «genger». In the structure of complex parametric nomination the only one conerete qualitative element from the whole combination of qualities becomes the leading one. The cultural-archetypal dominant element determines. In each concrete situation, the choice of preferable prototypal motivated quality.

Beam Induced Hydrodynamic Tunneling in the Future Circular Collider Components

CERN Document Server

AUTHOR|(CDS)2083092; Burkart, Florian; Schmidt, Rudiger; Shutov, A; Wollmann, Daniel; Piriz, A

2016-01-01

A future circular collider (FCC) has been proposed as a post-Large Hadron Collider accelerator, to explore particle physics in unprecedented energy ranges. The FCC is a circular collider in a tunnel with a circumference of 80–100 km. The FCC study puts an emphasis on proton-proton high-energy and electron-positron high-intensity frontier machines. A proton-electron interaction scenario is also examined. According to the nominal FCC parameters, each of the 50 TeV proton beams will carry an amount of 8.5 GJ energy that is equivalent to the kinetic energy of an Airbus A380 (560 t) at a typical speed of 850  km/h . Safety of operation with such extremely energetic beams is an important issue, as off-nominal beam loss can cause serious damage to the accelerator and detector components with a severe impact on the accelerator environment. In order to estimate the consequences of an accident with the full beam accidently deflected into equipment, we have carried out numerical simulations of interaction of a FCC...

Graham nominated to Head OSTP

Science.gov (United States)

President Ronald Reagan has nominated William R. Graham as science advisor and director of the Office of Science and Technology (OSTP). Graham, who is currently deputy director of the National Aeronautics and Space Administration (NASA), had been acting director of the agency until the nomination of James C. Fletcher.Graham's nomination, which must be confirmed by the U.S. Senate, comes 6 months after the resignation of George A. Keyworth from the post. John P. McTague had been acting science advisor since Keyworth's resignation (Eos, December 10, 1985, p. 1219).

Reliability of buildings in service limit state for maximum horizontal displacements

Directory of Open Access Journals (Sweden)

A. G. B. Corelhano

Full Text Available Brazilian design code ABNT NBR6118:2003 - Design of Concrete Structures - Procedures - [1] proposes the use of simplified models for the consideration of non-linear material behavior in the evaluation of horizontal displacements in buildings. These models penalize stiffness of columns and beams, representing the effects of concrete cracking and avoiding costly physical non-linear analyses. The objectives of the present paper are to investigate the accuracy and uncertainty of these simplified models, as well as to evaluate the reliabilities of structures designed following ABNT NBR6118:2003[1&] in the service limit state for horizontal displacements. Model error statistics are obtained from 42 representative plane frames. The reliabilities of three typical (4, 8 and 12 floor buildings are evaluated, using the simplified models and a rigorous, physical and geometrical non-linear analysis. Results show that the 70/70 (column/beam stiffness reduction model is more accurate and less conservative than the 80/40 model. Results also show that ABNT NBR6118:2003 [1] design criteria for horizontal displacement limit states (masonry damage according to ACI 435.3R-68(1984 [10] are conservative, and result in reliability indexes which are larger than those recommended in EUROCODE [2] for irreversible service limit states.

The influence of lateral beam profile modifications in scanned proton and carbon ion therapy: a Monte Carlo study

CERN Document Server

Parodi, K; Kraemer, M; Sommerer, F; Naumann, J; Mairani, A; Brons, S

2010-01-01

Scanned ion beam delivery promises superior flexibility and accuracy for highly conformal tumour therapy in comparison to the usage of passive beam shaping systems. The attainable precision demands correct overlapping of the pencil-like beams which build up the entire dose distribution in the treatment field. In particular, improper dose application due to deviations of the lateral beam profiles from the nominal planning conditions must be prevented via appropriate beam monitoring in the beamline, prior to the entrance in the patient. To assess the necessary tolerance thresholds of the beam monitoring system at the Heidelberg Ion Beam Therapy Center, Germany, this study has investigated several worst-case scenarios for a sensitive treatment plan, namely scanned proton and carbon ion delivery to a small target volume at a shallow depth. Deviations from the nominal lateral beam profiles were simulated, which may occur because of misaligned elements or changes of the beam optic in the beamline. Data have been an...

7 CFR 1221.101 - Nominations.

Science.gov (United States)

2010-01-01

... Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS... INFORMATION ORDER Sorghum Promotion, Research, and Information Order Sorghum Promotion, Research, and Information Board § 1221.101 Nominations. All nominations authorized under this section shall be made in the...

2 MeV, 60 kW dual-beam type electron accelerator irradiation facility

International Nuclear Information System (INIS)

Yotsumoto, Keiichi; Kanazawa, Takao; Haruyama, Yasuyuki; Agematsu, Takashi; Mizuhashi, Kiyoshi; Sunaga, Hiromi; Washino, Masamitsu; Tamura, Naoyuki

1984-02-01

The specification of new irradiation facility which has been constructed from 1978 through 1981 as the replacement of 1st Accelerator of JAERI, TRCRE are described. The accelerator is the Cockcroft-Walton type and both vertical and horizontal accelerating tubes are arranged on a single high voltage generator. Transferring of the high voltage to the horizontal accelerating tube is performed with the high voltage changing system in the pressure vessel. The output ratings of the accelerator are 2 MV of acceleration voltage and 30 mA of beam current. By providing the dual beam system, two irradiation rooms, one for vertical and the other for horizontal beam, are independently operationable. Persons can enter the horizontal irradiation room for experimental setting even when the vertical irradiation room is in operation. The specification of the buildings, the exhaust air treatment system, the irradiation conveyor and the safety observation system are also described. (author)

Round beams generated by vertical dispersion

International Nuclear Information System (INIS)

Bagley, P.

1990-01-01

Simulations suggest that in e + e - storage rings collisions of round beams (equal emittances and equal β*) can produce very large tune shifts and luminosities. We understand how to make equal β*s, but generating equal emittances is more difficult. We describe an equal emittance scheme that uses several skew quads to couple horizontal dispersion into vertical dispersion. These skew quads also produce a coupling bump. At the interaction point and at other points outside the coupling bump, the motion is not coupled, so that the 'A' normal mode corresponds to horizontal motion and the 'B' normal mode corresponds to vertical motion. We present a round beam lattice for CESR that incorporates this scheme

Horizontal maps of echo power in the lower stratosphere using the MU radar

Directory of Open Access Journals (Sweden)

M. Hirono

2004-03-01

Full Text Available In recent works, zenithal and azimuthal angle variations of echo power measured by VHF Stratosphere-Troposphere (ST radars have been analyzed in detail using different radar multi-beam configurations. It was found that the azimuthal angle corresponding to maximum echo power is closely related to the direction of the horizontal wind shear. These properties indicate that local wind shear affects the tilt of the scatterers. Moreover, horizontal maps of echo power collected using a large set of beams steered pulse-to-pulse up to 40 degrees off zenith revealed that the power distribution pattern in the troposphere is often skewed. In this work, a three-dimensional description of echo power variations up to 24 degrees off zenith is shown for measurements in the lower stratosphere (i.e. up to approximately 20km using a "sequential multi-beam" (SMB configuration. Such a description was not possible above the tropopause with classical multi-beam configurations because of the loss of radar sensitivity due to the limited integration time by the use of a large number of beams. This work attempts to complete previous descriptions of the phenomenon by some observations in the lower stratosphere discussed in association with complementary balloon measurements.

Key words. Meteorology and atmospheric dynamics (turbulence – Radio Science (remote sensing

Beam Cleaning in Experimental IRs in HL-LHC for the Incoming Beam

CERN Document Server

Garcia-Morales, H; Bruce, Roderik; Redaelli, Stefano

2015-01-01

The HL-LHC will store 675 MJ of energy per beam, about 300 MJ more than the nominal LHC. Due to the increase in stored energy and a different interaction region (IR) optics layout, the collimation system for the incoming beam must be revisited in order to avoid dangerous losses that could cause quenches or machine damage. This paper studies the effectiveness of the current LHC collimation system in intercepting cleaning losses close to the experiments in the HL-LHC. The study reveals that additional tertiary collimators would be beneficial in order to protect not only the final focusing triplets but also the two quadrupoles further upstream.

Beam cleaning of the incoming beam in experimental IRs in HL-LHC

CERN Document Server

Garcia Morales, Hector; Redaelli, Stefano; De Maria, Riccardo; CERN. Geneva. ATS Department

2017-01-01

The HL-LHC will store 675 MJ of energy per beam, about 300 MJ more than the nominal LHC. Due to the increase in stored energy and a different interaction region (IR) layout and optics design, the collimation system for the incoming beam must be revisited in order to avoid dangerous losses that could cause quenches and machine damage. This paper studies the effectiveness of the current LHC collimation system in intercepting cleaning losses close to the experiments in the HL-LHC. The study reveals that in addition to the triplet also the Q4 needs local protection, which could be provided by an additional pair of TCTs.

Variation of Shrinkage Strain within the Depth of Concrete Beams

Directory of Open Access Journals (Sweden)

Jong-Hyun Jeong

2015-11-01

Full Text Available The variation of shrinkage strain within beam depth was examined through four series of time-dependent laboratory experiments on unreinforced concrete beam specimens. Two types of beam specimens, horizontally cast and vertically cast, were tested; shrinkage variation was observed in the horizontally cast specimens. This indicated that the shrinkage variation within the beam depth was due to water bleeding and tamping during the placement of the fresh concrete. Shrinkage strains were measured within the beam depth by two types of strain gages, surface-attached and embedded. The shrinkage strain distribution within the beam depth showed a consistent tendency for the two types of gages. The test beams were cut into four sections after completion of the test, and the cutting planes were divided into four equal sub-areas to measure the aggregate concentration for each sub-area of the cutting plane. The aggregate concentration increased towards the bottom of the beam. The shrinkage strain distribution was estimated by Hobbs’ equation, which accounts for the change of aggregate volume concentration.

BATMAN beam properties characterization by the beam emission spectroscopy diagnostic

Science.gov (United States)

Bonomo, F.; Ruf, B.; Barbisan, M.; Cristofaro, S.; Schiesko, L.; Fantz, U.; Franzen, P.; Pasqualotto, R.; Riedl, R.; Serianni, G.; Wünderlich, D.

2015-04-01

The ITER neutral beam heating systems are based on the production and acceleration of negative ions (H/D) up to 1 MV. The requirements for the beam properties are strict: a low core beam divergence (BATMAN (BAvarian Test MAchine for Negative ions) allows for deepening the knowledge of the determination of the beam properties. One of the diagnostics routinely used to this purpose is the Beam Emission Spectroscopy (BES): the Hα light emitted in the beam is detected and the corresponding spectra are evaluated to estimate the beam divergence and the stripping losses. The BES number of lines of sight in BATMAN has been recently increased: five horizontal lines of sight providing a vertical profile of the beam permit to characterize the negative ion beam properties in relation to the source parameters. Different methods of Hα spectra analysis are here taken into account and compared for the estimation of the beam divergence and the amount of stripping. In particular, to thoroughly study the effect of the space charge compensation on the beam divergence, an additional hydrogen injection line has been added in the tank, which allows for setting different background pressure values (one order of magnitude, from about 0.04 Pa up to the source pressure) in the beam drift region.

7 CFR 958.28 - Nominations.

Science.gov (United States)

2010-01-01

... and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE ONIONS GROWN IN CERTAIN DESIGNATED... Nominations. Nominations from which the Secretary may select the members of the Idaho-Eastern Oregon Onion... more meetings of producers and of handlers in each of the districts, or portions of the production area...

7 CFR 932.29 - Nominations.

Science.gov (United States)

2010-01-01

... Secretary: (i) Meetings shall be held in each producer district for the purpose of selecting candidates for the member and alternate member nominations; (ii) Those candidates selected at the producer meetings... meetings called by the committee, the independent handlers shall nominate a qualified person for each...

Generation of vector beams using a double-wedge depolarizer: Non-quantum entanglement

Science.gov (United States)

Samlan, C. T.; Viswanathan, Nirmal K.

2016-07-01

Propagation of horizontally polarized Gaussian beam through a double-wedge depolarizer generates vector beams with spatially varying state of polarization. Jones calculus is used to show that such beams are maximally nonseparable on the basis of even (Gaussian)-odd (Hermite-Gaussian) mode parity and horizontal-vertical polarization state. The maximum nonseparability in the two degrees of freedom of the vector beam at the double wedge depolarizer output is verified experimentally using a modified Sagnac interferometer and linear analyser projected interferograms to measure the concurrence 0.94±0.002 and violation of Clauser-Horne-Shimony-Holt form of Bell-like inequality 2.704±0.024. The investigation is carried out in the context of the use of vector beams for metrological applications.

Final design of kaon beam K2 at KEK

International Nuclear Information System (INIS)

Kurokawa, Shin-ichi; Yamamoto, Akira.

1977-09-01

Final design of the 2.3 GeV/c kaon beam K2 is given. The K2 beam starts from the production target in slow extracted beam. Momentum range is 1 GeV/c through 2.3 GeV/c. Nominal total beam length is 27.9 m and solid-angle momentum acceptance is 6.25 msr%ΔP/P. Using a platinum target of diameter 3 mm and length 6 cm, 2.0 GeV/c beam fluxes of 1.0 x 10 6 K + and 5.2 x 10 5 K - per 10 12 13 GeV/c incident protons are expected at the final focus. (auth.)

Condensation heat transfer characteristics of R410A-oil mixture in 5 mm and 4 mm outside diameter horizontal microfin tubes

Energy Technology Data Exchange (ETDEWEB)

Huang, Xiangchao; Ding, Guoliang; Hu, Haitao; Zhu, Yu [Institute of Refrigeration and Cryogenics, Shanghai Jiaotong University, Shanghai 200240 (China); Gao, Yifeng [International Copper Association Shanghai Office, Shanghai 200020 (China); Deng, Bin [Institute of Heat Transfer Technology, Golden Dragon Precise Copper Tube Group Inc., Shanghai 200135 (China)

2010-10-15

Condensation heat transfer characteristics of R410A-oil mixture in 5 mm and 4 mm outside diameter horizontal microfin tubes were investigated experimentally. The experimental condensing temperature is 40 C, and nominal oil concentration range is from 0% to 5%. The test results indicate that the presence of oil deteriorates the heat transfer. The deterioration effect is negligible at nominal oil concentration of 1%, and becomes obvious with the increase of nominal oil concentration. At 5% nominal oil concentration, the heat transfer coefficient of R410A-oil mixture is found to have a maximum reduction of 25.1% and 23.8% for 5 mm and 4 mm tubes, respectively. The predictabilities of the existing condensation heat transfer correlations were verified with the experimental data, and Yu and Koyama correlation shows the best predictability. By replacing the pure refrigerant properties with the mixture's properties, Yu and Koyama correlation has a deviation of -15% to + 20% in predicting the local condensation heat transfer coefficient of R410A-oil mixture. (author)

Simulation of Solar Radiation Incident on Horizontal and Inclined Surfaces

Directory of Open Access Journals (Sweden)

MA Basunia

2012-12-01

Full Text Available A computer model was developed to simulate the hourly, daily and monthly average of daily solar radiation on horizontal and inclined surfaces. The measured hourly and daily solar radiation was compared with simulated radiation, and favourable agreement was observed for the measured and predicted values on clear days. The measured and simulated monthly averages of total (diffuse and beam daily solar radiation were compared and a reasonable agreement was observed for a number of stations in Japan. The simulation showed that during the rice harvesting season, September to October, there is a daily average of 14.7 MJ/m2 of solar irradiation on a horizontal surface in Matsuyama, Japan. There is a similar amount of solar radiation on a horizontal surface during the major rice harvesting season, November to December, in Bangladesh. This radiation can be effectively utilized for drying rough rice and other farm crops.

First operational experience with the LHC machine protection system when operating with beam energies beyond the 100MJ range

CERN Document Server

Assmann, R; Ferro-Luzzi, M; Goddard, B; Lamont, M; Schmidt, R; Siemko, A; Uythoven, J; Wenninger, J; Zerlauth, M

2012-01-01

The Large Hadron Collider (LHC) at CERN has made remarkable progress during 2011, surpassing its ambitious goal for the year in terms of luminosity delivered to the LHC experiments. This achievement was made possible by a progressive increase of beam intensities by more than 5 orders of magnitude during the first months of operation, reaching stored beam energies beyond the 100MJ range at the end of the year, less than a factor of 4 from the nominal design value. The correct functioning of the machine protection systems is vital during the different operational phases, for initial operation and even more when approaching nominal beam parameters where already a small fraction of the stored energy is sufficient to damage accelerator equipment or experiments in case of uncontrolled beam loss. Safe operation of the machine in presence of such high intensity proton beams is guaranteed by the interplay of many different systems: beam dumping system, beam interlocks, beam instrumentation, equipment monitoring, colli...

NASA, NOAA administrators nominated

Science.gov (United States)

Richman, Barbara T.

President Ronald Reagan recently said he intended to nominate James Montgomery Beggs as NASA Administrator and John V. Byrne as NOAA Administrator. These two positions are key scientific posts that have been vacant since the start of the Reagan administration on January 20. The President also said he intends to nominate Hans Mark as NASA Deputy Administrator. At press time, Reagan had not designated his nominee for the director of the Office of Science and Technology Policy.

Formation of a uniform ion beam using octupole magnets for BioLEIR facility at CERN

Science.gov (United States)

Amin, T.; Barlow, R.; Ghithan, S.; Roy, G.; Schuh, S.

2018-04-01

The possibility to transform the Low Energy Ion Ring (LEIR) accelerator at CERN into a multidisciplinary, biomedical research facility (BioLEIR) was investigated based on a request from the biomedical community. BioLEIR aims to provide a unique facility with a range of fully stripped ion beams (e.g. He, Li, Be, B, C, N, O) and energies suitable for multidisciplinary biomedical, clinically-oriented research. Two horizontal and one vertical beam transport lines have been designed for transporting the extracted beam from LEIR to three experimental end-stations. The vertical beamline was designed for a maximum energy of 75 MeV/u, while the two horizontal beamlines shall deliver up to a maximum energy of 440 MeV/u. A pencil beam of 4.3 mm FWHM (Full Width Half Maximum) as well as a homogeneous broad beam of 40 × 40 mm2, with a beam homogeneity better than ±4%, are available at the first horizontal (H1) irradiation point, while only a pencil beam is available at the second horizontal (H2) and vertical (V) irradiation points. The H1 irradiation point shall be used to conduct systematic studies of the radiation effect from different ion species on cell-lines. The H1 beamline was designed to utilize two octupole magnets which transform the Gaussian beam distribution at the target location into an approximately uniformly distributed rectangular beam. In this paper, we report on the multi-particle tracking calculations performed using MAD-X software suite for the H1 beam optics to arrive at a homogeneous broad beam on target using nonlinear focusing techniques, and on those to create a Gaussian pencil beam on target by adjusting quadrupoles strengths and positions.

LHC beam dump system : analysis of beam commissioning, performance and the consequences of abnormal operation

International Nuclear Information System (INIS)

Kramer, T.

2011-01-01

The LHC accelerates proton beams to a momentum of up to 7 TeV/c. At this energy level and with nominal beam intensity the stored energy of 360 MJ per beam is sufficient to melt 500 kg of copper. In addition up to 10 GJ are stored within the LHC magnet system at top energy. lt is obvious that such a machine needs well designed safety and protection systems. The LHC Beam Dump System (LBDS) is such a system and one of the most critical once concerning machine protection and safe operation. lt is used to dispose of high intensity beams between 450 GeV and 7 TeV and is thus designed to fast extract beam in a loss free way and to transfer it to an external absorber. For each ring systems of 15 horizontal fast kicker magnets (MKD), 15 vertically deflecting magnetic septa (MSD) and 10 diluter kicker magnets (MKB) are installed. This thesis is concerned with the analysis of the LBDS performance under normal operating parameters as well as under abnormal conditions like in the event of asynchronous beam abort or missing MKD elements. Therefore a sophisticated simulation environment was developed based on the use of the MAD-X tracking code. A system of tracking jobs was set up to study failure cases and losses for various dump events. Those jobs can be distributed to available CPU power and be calculated in parallel. Studies into the consequences of abnormal beam dump actions have been performed. Different error scenarios have been evaluated including an asynchronous dump action, prefire cases, and the impact of different orbit and collimator settings. Losses at locations in the ring and the beam dump transfer lines have been quantified as a function of different settings of the dump system protection elements. The implications for the setup and operation of these protection elements are discussed. Particle distributions can be created according to the used orbit. Simulations with different orbit parameters (including magnet field errors, beam position read out errors

Beam position measurement system at the Fermilab main accelerator

International Nuclear Information System (INIS)

Kerns, Q.A.

1975-01-01

The beam position system of the Fermilab Main Ring contains one horizontal and one vertical Electrostatic Beam Pickup in each of the 96 cells of the machine. A pair of 75 ohm cables transmits the induced signal from the machine tunnel to the nearest service building. In each of the 24 service buildings, there is a solid-state multiplexer and a beam position detector which processes the A-B signal pairs to produce an intensity-normalized voltage proportional to beam displacement. This voltage is digitized, read into buffer of the Lockheed MAC A, and in turn transferred to the Xerox 530. Horizontal or vertical orbits can be obtained in 50 millisec. Orbits are obtained at injection and at a Main Ring Sample time, if requested, anywhere on the acceleration cycle. Injection orbits can be flattened automatically by a program that sets dipole trim magnets. (auth)

Nominalization in Igbo Language: A Morphological Approach ...

African Journals Online (AJOL)

Nominalization is a process of creating nouns from other word classes. The Igbo language as a verbal language derives so many nominal from verbs. Some scholars of Igbo studies are not well informed on how so many nominal have their root or etymology on verb roots. In the light of this background, the researcher ...

Polarized proton target with horizontal spin orientation

International Nuclear Information System (INIS)

Bunyatova, Eh.I.; Kiselev, Yu.F.; Kozlenko, N.G.

1988-01-01

Proton target, the polarization vector of which may be arbitrary oriented in horizontal plane relatively to the beam, is developed and tested. 70% value of polarization is obtained. 0.6 K temperature is acquired through 3 He pumping out continuous cycle. 1.2-propylene glycol - Cr(V) was used as working medium. Magnetic system is made in the form of Helmholtz sperconducting coils with working curren close to critical one. Target polarization is measured by NMR technique using original system of proton signal processing

Deverbal Nominals and Telicity in Japanese.

Science.gov (United States)

Tsujimura, Natsuko; Iida, Masayo

1999-01-01

Investigates deverbal nominalization involving the suffix "kake" in Japanese. Argues that kake nominalization induces two different meanings, the halfway and the inception reading, and different constraints are called for depending on these two meanings. (Author/VWL)

BEARING CAPACITY OF A HORIZONTALLY LOADED SINGLE PILE SUPPORT WITH SLEEPERS

Directory of Open Access Journals (Sweden)

Buslov Anatoliy Semenovich

2015-09-01

Full Text Available The supports of a overhead wiring used in transport take up substantial loads both because of wires and constructions holding them and wind, dynamic and other extraordinary impacts. In case of using single-member piles a question about their stability appears. For this reason different sleepers constructions are used. In order to improve the bearing capacity of horizontally loaded single pile supports of the contact systems used in urban, road and rail transport, power lines, etc.., it is recommended to use sleepers as horizontally laid under the ground in the depth of support beams. The calculation methods for different support sleepers of different lengths and cross sections are not well investigated. The proposed calculation method allows determining the carrying capacity of horizontally loaded bearings with soil pieces of different structural dimensions and their location in the soil, which allows choosing the best option for cost and material consumption. The calculations offered by the authors prove the efficiency of sleepers use in order to increase the bearing capacity of horizontally loaded piles and the possibility to chose their size.

Production of intermediate energy beams by high speed rotors

International Nuclear Information System (INIS)

Nutt, C.W.; Bale, T.J.; Cosgrove, P.; Kirby, M.J.

1975-01-01

A rotor apparatus intended for the study of gas/surface interaction processes is presently nearing completion. The carbon fiber rotors under consideration are constructed with shapes derived from long thin cylindrical rods oriented with the longest axis in a horizontal plane, and spun in a horizontal plane about an axis which is perpendicular to the long axis and passes through the mid-point of the cylinder. The beam formation processes are discussed and rotor diagrams presented. Performance of these types of high speed rotor show them to have a very important future as sources of intermediate energy molecular beams

Beam property studies in the PLS diagnostic beamline

CERN Document Server

Ko, I S; Seon, D K; Kim, C B; Lee, T Y

1999-01-01

A diagnostic beamline has been operated in the Pohang Light Source (PLS) storage ring for the diagnostics of electron and photon beam properties. It consists of two 1:1 imaging systems: a visible-light imaging system and a soft X-ray imaging system. We have measured the transverse and the longitudinal structures of beams by using a streak camera to obtain a visible image. Accurate transverse beam size have been measured to be 186 mu m horizontally and 43.1 mu m vertically by using soft X-ray images with minimum diffraction errors. The corresponding emittances are 11.7 nm-rad horizontally and 0.59 nm-rad vertically. By comparing the measured data with the design values, we confirmed that the PLS storage ring has reached its designed performance within an error of 3.3 % in the transverse direction.

Performance test results of ion beam transport for SST-1 neutral beam injector

Energy Technology Data Exchange (ETDEWEB)

Jana, M R; Mattoo, S K [Institute for Plasma Research Bhat, Gandhinagar-382428, Gujarat (India); Uhlemann, R, E-mail: mukti@ipr.res.i [Forschungszentrum Juelich, Institute fur Energieforschung IEF-4, Plasmaphysik D-52425 Juelich (Germany)

2010-02-01

A neutral beam injector is built at IPR to heat the plasma of SST-1 and its upgrade. It delivers a maximum beam power of 1.7 MW for 55 kV Hydrogen beam or 80 kV Deuterium beam. At lower beam voltage, the delivered power falls to 500 kW at 30 kV Hydrogen beam which is adequate to heat SST-1 plasma ions to {approx} 1 keV. Process of acceleration of ions to the required beam voltage, conversion of ions to neutrals and removal of un-neutralized ions and the beam diagnostic systems occupy a large space. The consequence is that linear extent of the neutral beam injector is at least a few meters. Also, port access provides a very narrow duct. Even a very good injector design and fabrication practices keep beam divergence at a very low but finite value. The result is beam transport becomes an important issue. Since a wide area beam is constructed by hundreds of beam lets, it becomes essential they be focused in such a way that beam transport loss is minimized. Horizontal and vertical focal lengths are two parameters, in addition to beam divergence, which give a description of the beam transport. We have obtained these two parameters for our injector by using beam transport code; making several hundred simulation runs by varying optical parameters of the beam. The selected parameters set has been translated into the engineering features of the extractor grid set of the ion source. Aperture displacement technique is used to secure the horizontal beam focusing at 5.4 m. Combination of both aperture displacement and inclining of two grid halves to {approx} 17 mrad are secured for vertical beam focusing at 7 m from earth grid of the ion source. The gaps between the design, engineered and performance tested values usually arise due to lack of exercising control over fabrication processes or due to inaccuracies in the assumption made in the model calculations of beam optics and beam transport. This has been the case with several injectors, notably with JET injector. To overcome

Medical linear accelerator mounted mini-beam collimator: design, fabrication and dosimetric characterization.

Science.gov (United States)

Cranmer-Sargison, G; Crewson, C; Davis, W M; Sidhu, N P; Kundapur, V

2015-09-07

The goal of this work was to design, build and experimentally characterize a linear accelerator mounted mini-beam collimator for use at a nominal 6 MV beam energy. Monte Carlo simulation was used in the design and dosimetric characterization of a compact mini-beam collimator assembly mounted to a medical linear accelerator. After fabrication, experimental mini-beam dose profiles and central axis relative output were measured and the results used to validate the simulation data. The simulation data was then used to establish traceability back to an established dosimetric code of practice. The Monte Carlo simulation work revealed that changes in collimator blade width have a greater influence on the valley-to-peak dose ratio than do changes in blade height. There was good agreement between the modeled and measured profile data, with the exception of small differences on either side of the central peak dose. These differences were found to be systematic across all depths and result from limitations associated with the collimator fabrication. Experimental mini-beam relative output and simulation data agreed to better than ± 2.0%, which is well within the level of uncertainty required for dosimetric traceability of non-standard field geometries. A mini-beam collimator has now been designed, built and experimentally characterized for use with a commercial linear accelerator operated at a nominal 6 MV beam energy.

Instability of compensated beam-beam collisions

International Nuclear Information System (INIS)

Rosenzweig, J.B.; Autin, B.; Chen, Pisin.

1989-01-01

The beam-beam disruption phenomena in linear colliders are increasingly seen as a source of serious problems for these machines. A plasma compensation scheme, in which the motion of the plasma electrons in the presence of the colliding beams provides neutralizing charge and current densities, has been proposed and studied. But natural alternative to this scheme is to consider the overlapping of nearly identical high energy e + and e/sup /minus// bunches, and the collision of two such pairs - in other words, collision of two opposing relativistic positronium plasmas. It should be noticed that while the luminosity for all collisions is increased by a factor of four in this scheme, the event rate for e + e/sup /minus// collisions is only increased by a factor of two. The other factor of two corresponds to the addition of e + e + and e/sup /minus//e/sup /minus// collisions to the interaction point. This beam compensation scheme, which has been examined through computer simulation by Balakin and Solyak in the Soviet Union, promises full neutralization of beam charges and currents. These numerical investigations have shown that plasma instabilities exist in this nominally neutral system. Although the implementation of this idea seems technically daunting, the potential benefits (beamstrahlung and disruption suppression, relaxation of final focus system constraints) are such that we should consider the physics of these collisions further. In the remainder of this paper, we theoretically analyze the issues of stability and bunch parameter tolerances in this scheme. 11 refs

Endogenous Growth, Monetary Shocks and Nominal Rigidities

OpenAIRE

Annicchiarico, Barbara; Pelloni, Alessandra; Lorenza, Rossi

2010-01-01

We introduce endogenous growth in an otherwise standard NK model with staggered prices and wages. Some results follow: (i) monetary volatility negatively affects long-run growth; (ii) the relation between nominal volatility and growth depends on the persistence of the nominal shocks and on the Taylor rule considered; (iii) a Taylor rule with smoothing increases the negative effect of nominal volatility on mean growth.

The echolocation transmission beam of free-ranging Indo-Pacific humpback dolphins (Sousa chinensis).

Science.gov (United States)

Fang, Liang; Wu, Yuping; Wang, Kexiong; Pine, Matthew K; Wang, Ding; Li, Songhai

2017-08-01

While the transmission beam of odontocetes has been described in a number of studies, the majority of them that have measured the transmission beam in two dimensions were focused on captive animals. Within the current study, a dedicated cross hydrophone array with nine elements was used to investigate the echolocation transmission beam of free-ranging Indo-Pacific humpback dolphins. A total of 265 on-axis clicks were analyzed, from which the apparent peak to peak source levels ranged between 168 to 207 dB (mean 184.5 dB ± 6.6 dB). The 3-dB beam width along the horizontal and vertical plane was 9.6° and 7.4°, respectively. Measured separately, the directivity index of the horizontal and vertical plane was 12.6 and 13.5 dB, respectively, and the overall directivity index (both planes combined) was 29.5 dB. The beam shape was slightly asymmetrical along the horizontal and vertical axis. Compared to other species, the characteristics of the transmitting beam of Indo-Pacific humpback dolphins were relatively close to the bottlenose dolphin (Tursiops truncatus), likely due to the similarity in the peak frequency and waveform of echolocation clicks and comparable body sizes of the two species.

Accidental Beam Losses and Protection in the LHC

Science.gov (United States)

Schmidt, R.; Working Group On Machine Protection

2005-06-01

At top energy (proton momentum 7 TeV/c) with nominal beam parameters, each of the two LHC proton beams has a stored energy of 350 MJ threatening to damage accelerator equipment in case of accidental beam loss. It is essential that the beams are properly extracted onto the dump blocks in case of failure since these are the only elements that can withstand full beam impact. Although the energy stored in the beams at injection (450 GeV/c) is about 15 times smaller compared to top energy, the beams must still be properly extracted in case of large accidental beam losses. Failures must be detected at a sufficiently early stage and initiate a beam dump. Quenches and power converter failures will be detected by monitoring the correct functioning of the hardware systems. In addition, safe operation throughout the cycle requires the use of beam loss monitors, collimators and absorbers. Ideas of detection of fast beam current decay, monitoring of fast beam position changes and monitoring of fast magnet current changes are discussed, to provide the required redundancy for machine protection.

Accidental Beam Losses and Protection in the LHC

International Nuclear Information System (INIS)

Schmidt, R.; Wenninger, J.

2005-01-01

At top energy (proton momentum 7 TeV/c) with nominal beam parameters, each of the two LHC proton beams has a stored energy of 350 MJ threatening to damage accelerator equipment in case of accidental beam loss. It is essential that the beams are properly extracted onto the dump blocks in case of failure since these are the only elements that can withstand full beam impact. Although the energy stored in the beams at injection (450 GeV/c) is about 15 times smaller compared to top energy, the beams must still be properly extracted in case of large accidental beam losses. Failures must be detected at a sufficiently early stage and initiate a beam dump. Quenches and power converter failures will be detected by monitoring the correct functioning of the hardware systems. In addition, safe operation throughout the cycle requires the use of beam loss monitors, collimators and absorbers. Ideas of detection of fast beam current decay, monitoring of fast beam position changes and monitoring of fast magnet current changes are discussed, to provide the required redundancy for machine protection

Surface Resistance Measurements and Estimate of the Beam-Induced Resistive Wall Heating of the LHC Dipole Beam Screen

CERN Document Server

Caspers, Friedhelm; Ruggiero, F; Tan, J

1999-01-01

An estimate of the resistive losses in the LHC beam screen is given from cold surface resistance measurements using the shielded pair technique, with particular emphasis on the effect of a high magnetic field. Two different copper coating methods, namely electro-deposition and co-lamination, have been evaluated. Experimental data are compared with theories including the anomalous skin effect and the magneto-resistance effect. It is shown whether the theory underestimates or not the losses depends strongly on the RRR value, on the magnetic field and on the surface characteristics. In the pessimistic case and for nominal machine parameters, the estimated beam-induced resistive wall heating can be as large as 260 mW/m for two circulating beams.

Cryogenics system: strategy to achieve nominal performance and reliable operation

International Nuclear Information System (INIS)

Bremer, J.; Brodzinski, K.; Casas, J.; Claudet, S.; Delikaris, D.; Delruelle, N.; Ferlin, G.; Fluder, C.; Perin, A.; Perinic, G.; Pezzetti, M.; Pirotte, O.; Tavian, L.; Wagner, U.

2012-01-01

During the LHC operation in 2010 and 2011, the cryogenic system has achieved an availability level fulfilling the overall requirement. To reach this level, the cryogenic system has profited like many other beam-dependent systems from the reduced beam parameters. Therefore, impacts of some failures occurred during the LHC operation were mitigated by using the over-capacity margin, the existing built-in redundancy in between adjacent sector cryogenic plants and the 'cannibalization' of spares on two idle cryogenic plants. These two first years of operation were also crucial to identify the weaknesses of the present cryogenic maintenance plan and new issues like SEUs. After the LS1, nominal beam parameters are expected and the mitigated measures will be less effective or not applicable at all. Consequently, a consolidation plan to improve the MTBF and the MTTR of the LHC cryogenic system is under definition. Concerning shutdown periods, the present cryogenic sectorization imposes some restrictions in the type of interventions (e.g. cryo-magnet removal) which can be done without affecting the operating conditions of the adjacent sector. This creates additional constrains and possible extra down-time in the schedule of the shutdowns including the hardware commissioning. This presentation focuses on the consolidation plan foreseen during the LS1 to improve the performance of the LHC cryogenic system in terms of availability and sectorization. (authors)

Beam based measurement of beam position monitor electrode gains

Directory of Open Access Journals (Sweden)

D. L. Rubin

2010-09-01

Full Text Available Low emittance tuning at the Cornell Electron Storage Ring (CESR test accelerator depends on precision measurement of vertical dispersion and transverse coupling. The CESR beam position monitors (BPMs consist of four button electrodes, instrumented with electronics that allow acquisition of turn-by-turn data. The response to the beam will vary among the four electrodes due to differences in electronic gain and/or misalignment. This variation in the response of the BPM electrodes will couple real horizontal offset to apparent vertical position, and introduce spurious measurements of coupling and vertical dispersion. To alleviate this systematic effect, a beam based technique to measure the relative response of the four electrodes has been developed. With typical CESR parameters, simulations show that turn-by-turn BPM data can be used to determine electrode gains to within ∼0.1%.

Beam based measurement of beam position monitor electrode gains

Science.gov (United States)

Rubin, D. L.; Billing, M.; Meller, R.; Palmer, M.; Rendina, M.; Rider, N.; Sagan, D.; Shanks, J.; Strohman, C.

2010-09-01

Low emittance tuning at the Cornell Electron Storage Ring (CESR) test accelerator depends on precision measurement of vertical dispersion and transverse coupling. The CESR beam position monitors (BPMs) consist of four button electrodes, instrumented with electronics that allow acquisition of turn-by-turn data. The response to the beam will vary among the four electrodes due to differences in electronic gain and/or misalignment. This variation in the response of the BPM electrodes will couple real horizontal offset to apparent vertical position, and introduce spurious measurements of coupling and vertical dispersion. To alleviate this systematic effect, a beam based technique to measure the relative response of the four electrodes has been developed. With typical CESR parameters, simulations show that turn-by-turn BPM data can be used to determine electrode gains to within ˜0.1%.

Operating experience with high beam currents and transient beam loading in the SLC damping rings

International Nuclear Information System (INIS)

Minty, M.G.; Akre, R.; Krejcik, P.; Siemann, R.H.

1995-01-01

During the 1994 SLC run the nominal operating intensity in the damping rings was raised from 3.5 x 10 10 to greater than 4 x 10 10 particles per bunch (ppb). Stricter regulation of rf system parameters was required to maintain stability of the rf system and particle beam. Improvements were made in the feedback loops which control the cavity amplitude and loading angles. Compensation for beam loading was also required to prevent klystron saturation during repetition rate changes. To minimize the effects of transient loading on the rf system, the gain of the direct rf feedback loop and the loading angles were optimized

Single-shot beam size measurements using visible-light interferometry at CESR

Energy Technology Data Exchange (ETDEWEB)

Wang, S.T., E-mail: sw565@cornell.edu [Cornell Laboratory for Accelerator-based Science and Education, Cornell University, Ithaca, NY 14853 (United States); Holtzapple, R. [Physics Department, California Polytechnic State University, San Luis Obispo, CA 93407 (United States); Rubin, D.L. [Cornell Laboratory for Accelerator-based Science and Education, Cornell University, Ithaca, NY 14853 (United States)

2017-03-01

A new primary mirror for a visible-light beam size monitor (vBSM) was designed and installed in the Cornell Electron-Positron Storage Ring (CESR). The vertical angular acceptance of the mirror was doubled to allow double-slit interferometry with large slit separation (>12 mm). In addition, the diffraction associated with the first generation mirror has been eliminated. The resolution of the vertical beam size measurements has been dramatically improved but is ultimately limited by the beam motion. Two fast-response detectors, a Photomultiplier Tube (PMT) array and a gated camera, were employed to study the beam motion. The advantages and limitations of both devices are discussed in this paper. The gated camera was also used to measure single-shot beam width and motion of each bunch in a multi-bunch train. We measured significantly more horizontal motion of electron as compared to positron bunch trains in otherwise identical machine condition. This difference may be a signature for the difference between electron cloud build-up for positron bunch trains versus ions effects characteristic of electron bunch trains. - Highlights: • A new extraction mirror for synchrotron radiation was designed and installed in CESR. • The sensitivity of interferometer was increased and the diffraction effect was eliminated. • Two fast-response detectors were employed to study the effect of beam motion. • First time single-shot bunch-by-bunch horizontal beam size measurements using interferometry was observed from gated camera. • The difference in single bunch horizontal dynamics was observed between a positron and an electron train.

First beam in Linac4 DTL

CERN Multimedia

Katarina Anthony

2014-01-01

Following the installation of the Linac4 Drift Tube Linac (DTL) earlier this summer (see here), the first DTL tank saw beams at 12 MeV on 5 August.   Transverse emittance measured at 12 MeV after the DTL tank1 using a temporary slit-and-grid emittance device. You never forget your first beam. That was especially true for the Linac4 DTL team, as it followed years of design, construction and vigorous testing. "We performed countless measurements of the geometry, vacuum and magnet polarisation of the DTL tanks while we were in the workshop," says Suitbert Ramberger, project engineer for the Linac4 DTL. "Add that preparation to the excellent RF conditioning that we carried out in the weeks before the beam tests and I was confident that the acceleration with beam would fully meet expectations!" Indeed it did. Beam commissioning tests ran until 21 August and found the DTL operating with nominal transmission. This successful run has confirmed the innovative design ...

SU-E-T-273: Radiation Shielding for a Fixed Horizontal-Beam Linac in a Shipping Container and a Conventional Treatment Vault

International Nuclear Information System (INIS)

Hsieh, M; Balter, P; Beadle, B; Chi, P; Stingo, F; Court, L

2014-01-01

Purpose: A fixed horizontal-beam linac, where the patient is treated in a seated position, could lower the overall costs of the treatment unit and room shielding substantially. This design also allows the treatment room and control area to be contained within a reduced space, such as a shipping container. The main application is the introduction of low-cost, high-quality radiation therapy to low- and middle-income regions. Here we consider shielding for upright treatments with a fixed-6MV-beam linac in a shipping container and a conventional treatment vault. Methods: Shielding calculations were done for two treatment room layouts using calculation methods in NCRP Report 151: (1) a shipping container (6m × 2.4m with the remaining space occupied by the console area), and (2) the treatment vault in NCRP 151 (7.8m by 5.4m by 3.4m). The shipping container has a fixed gantry that points in one direction at all times. For the treatment vault, various beam directions were evaluated. Results: The shipping container requires a primary barrier of 168cm concrete (4.5 TVL), surrounded by a secondary barrier of 3.6 TVL. The other walls require between 2.8–3.3 TVL. Multiple shielding calculations were done along the side wall. The results show that patient scatter increases in the forward direction and decreases dramatically in the backward direction. Leakage scatter also varies along the wall, depending largely on the distance between the gantry and the wall. For the treatment room, fixed-beam requires a slightly thicker primary barrier than the conventional linac (0.6 TVL), although this barrier is only needed in the center of one wall. The secondary barrier is different only by 0–0.2 TVL. Conclusion: This work shows that (1) the shipping container option is achievable, using indigenous materials for shielding and (2) upright treatments can be performed in a conventional treatment room with minimal additional shielding. Varian Medical Systems

SU-E-T-273: Radiation Shielding for a Fixed Horizontal-Beam Linac in a Shipping Container and a Conventional Treatment Vault

Energy Technology Data Exchange (ETDEWEB)

Hsieh, M; Balter, P; Beadle, B; Chi, P; Stingo, F; Court, L [The University of Texas MD Anderson Cancer Center, Houston, TX (United States)

2014-06-01

Purpose: A fixed horizontal-beam linac, where the patient is treated in a seated position, could lower the overall costs of the treatment unit and room shielding substantially. This design also allows the treatment room and control area to be contained within a reduced space, such as a shipping container. The main application is the introduction of low-cost, high-quality radiation therapy to low- and middle-income regions. Here we consider shielding for upright treatments with a fixed-6MV-beam linac in a shipping container and a conventional treatment vault. Methods: Shielding calculations were done for two treatment room layouts using calculation methods in NCRP Report 151: (1) a shipping container (6m × 2.4m with the remaining space occupied by the console area), and (2) the treatment vault in NCRP 151 (7.8m by 5.4m by 3.4m). The shipping container has a fixed gantry that points in one direction at all times. For the treatment vault, various beam directions were evaluated. Results: The shipping container requires a primary barrier of 168cm concrete (4.5 TVL), surrounded by a secondary barrier of 3.6 TVL. The other walls require between 2.8–3.3 TVL. Multiple shielding calculations were done along the side wall. The results show that patient scatter increases in the forward direction and decreases dramatically in the backward direction. Leakage scatter also varies along the wall, depending largely on the distance between the gantry and the wall. For the treatment room, fixed-beam requires a slightly thicker primary barrier than the conventional linac (0.6 TVL), although this barrier is only needed in the center of one wall. The secondary barrier is different only by 0–0.2 TVL. Conclusion: This work shows that (1) the shipping container option is achievable, using indigenous materials for shielding and (2) upright treatments can be performed in a conventional treatment room with minimal additional shielding. Varian Medical Systems.

29 CFR 452.58 - Self-nomination.

Science.gov (United States)

2010-07-01

... GENERAL STATEMENT CONCERNING THE ELECTION PROVISIONS OF THE LABOR-MANAGEMENT REPORTING AND DISCLOSURE ACT... candidates and thus is inconsistent with the provisions of title IV. 34 Self-nomination is permissible only if the members are afforded additional methods whereby they may nominate the candidates of their...

Present status of beam position stabilization at photon factory storage ring

International Nuclear Information System (INIS)

Nakamura, Norio

1990-01-01

Stabilization of photon beam position became a major issue in the operation of the storage rings dedicated as synchrotron radiation source. At the Photon Factory storage ring (PF ring), the orbit movement appeared remarkably when the low-emittance operation started. This orbit movement became a serious problem to synchrotron radiation users because the photon beam to drift with a large amplitude. The horizontal and vertical orbit feedback systems were constructed and developed in order to suppress the orbit movement globally. As a result, the horizontal and vertical orbit movements were reduced by a factor of five and ten, respectively. In addition, another type of feedback system using a local bump was constructed. In the test operation, this system could remove the fast photon beam motion as well as the slow photon beam drift for a beamline. (author)

The IFMIF-EVEDA accelerator beam dump design

International Nuclear Information System (INIS)

Iglesias, D.; Arranz, F.; Arroyo, J.M.; Barrera, G.; Branas, B.; Casal, N.; Garcia, M.; Lopez, D.; Martinez, J.I.; Mayoral, A.; Ogando, F.; Parro, M.; Oliver, C.; Rapisarda, D.; Sanz, J.; Sauvan, P.; Ibarra, A.

2011-01-01

The IFMIF-EVEDA accelerator will be a 9 MeV, 125 mA cw deuteron accelerator prototype for verifying the validity of the 40 MeV accelerator design for IFMIF. A beam dump designed for maximum power of 1.12 MW will be used to stop the beam at the accelerator exit. The conceptual design for the IFMIF-EVEDA accelerator beam dump is based on a conical beam stop made of OFE copper. The cooling system uses an axial high velocity flow of water pressurized up to 3.4 x 10 5 Pa to avoid boiling. The design has been shown to be compliant with ASME mechanical design rules under nominal full power conditions. A sensitivity analysis has been performed to take into account the possible margin on the beam properties at the beam dump entrance. This analysis together with the study of the maintenance issues and the mounting and dismounting operations has led to the complete design definition.

UHV photoelectron x-ray beam position monitor

International Nuclear Information System (INIS)

Johnson, E.D.; Oversluizen, T.

1989-01-01

As part of our research program to develop viable beam position monitors for both the X-ray and VUV beamlines at the NSLS, we have constructed vertical photon beam position monitors which are presently mounted in two front-ends in the X-ray ring. These area-type detectors are located before the safety shutters and are, therefore, able to monitor the beam position even during injection. The features of this type of monitor which contribute to its long-term stability, position sensitivity, and immunity to horizontal beam motion have been examined and will be discussed. 6 refs., 4 figs

Nominal Group as Qualifier to "Someone"

Science.gov (United States)

Sujatna, Eva Tuckyta Sari; Wahyuni, Sri

2017-01-01

The paper titled "Nominal Group as Qualifier to 'Someone'" investigated types of qualifiers which are embedded to the head "someone" in a nominal group. This research was conducted in the light of Systemic Functional Linguistics analysis. The data was analyzed, classified then described using descriptive qualitative method.…

Parasitic crossing at an asymmetric B factory, APIARY

International Nuclear Information System (INIS)

Chin, Y.H.

1991-05-01

Effects of parasitic crossings (''near miss'' collisions of two counter-rotating beams at unwanted positions near the IP) are studied in terms of computer simulations for an asymmetric B Factory, APIARY- 6.3d. Beams are separated horizontally at the first parasitic crossing points by about 7.6 times the horizontal rms size of the low energy beam (the larger in size of the two beams), σ 0x,+ . Simulations, including both the beam collision at the IP and parasitic crossings, have been performed for different separation distances, d. It is found that the ratio d/σ 0x,+ is a good scaling parameter of beam blowup behavior. The results show that beam blowup due to the parasitic crossings is diminished for d ≥ 7σ 0x,+ , in agreement with the bunch separation experiment at CESR. Thus, the nominal separation 7.6 σ 0x,+ turns out to be acceptable, but with only a small margin. Some methods to mitigate the effects of the parasitic crossings are discussed. 3 refs. , 5 figs., 2 tabs

Size effect in self consolidating concrete beams with and without ...

Indian Academy of Sciences (India)

the decrease in nominal stress of notched beam is more when compared with that ... The differences between HPC and SCC is essentially in the use of special .... elements fail in ductile or plastic manner, while large sized elements of the ...

Protection against Accidental Beam Losses at the LHC

CERN Document Server

Wenninger, Jörg

2005-01-01

Protection of the LHC against uncontrolled beam losses is of prime importance due to the very high stored beam energy. For nominal beam intensities, each of the two 7 TeV/c proton beams has a stored energy of 360 MJ threatening to damage accelerator equipment. At injection a number of passive beam absorbers must be correctly positioned and specific procedures have been proposed to ensure safe injection of high intensity. The LHC beam dump block being the only LHC element that can safety absorb the full LHC beam, it is essential that the beams are extracted unto the dump block in case of emergency. The failure time constants extend from 100 microseconds to few seconds depending on the equipment. Failures must be detected at a sufficiently early stage and transmitted to the beam interlock system that triggers the beam dumping system. To ensure safe operation the machine protection system uses a variety of systems to detect such failures. The strategy for protection of the LHC will be illustrated, with emphasis ...

Petition nominations for 1990-1992

Science.gov (United States)

The nominees listed below are those of the Union and section nominating committees and have been approved by the AGU Council.Nominations may also be made by membership petition. There are no age, nationality, residence or other analogous restrictions on who may serve as a n officer. Petitions should be sent to the General Secretary, AGU, 2000 Florida Avenue N.W., Washington, DC 20009. They must be received no later than July 7, 1989.

BATMAN beam properties characterization by the beam emission spectroscopy diagnostic

International Nuclear Information System (INIS)

Bonomo, F.; Ruf, B.; Schiesko, L.; Fantz, U.; Franzen, P.; Riedl, R.; Wünderlich, D.; Barbisan, M.; Pasqualotto, R.; Serianni, G.; Cristofaro, S.

2015-01-01

The ITER neutral beam heating systems are based on the production and acceleration of negative ions (H/D) up to 1 MV. The requirements for the beam properties are strict: a low core beam divergence (< 0.4 °) together with a low source pressure (≤ 0.3 Pa) would permit to reduce the ion losses along the beamline, keeping the stripping particle losses below 30%. However, the attainment of such beam properties is not straightforward. At IPP, the negative ion source testbed BATMAN (BAvarian Test MAchine for Negative ions) allows for deepening the knowledge of the determination of the beam properties. One of the diagnostics routinely used to this purpose is the Beam Emission Spectroscopy (BES): the H α light emitted in the beam is detected and the corresponding spectra are evaluated to estimate the beam divergence and the stripping losses. The BES number of lines of sight in BATMAN has been recently increased: five horizontal lines of sight providing a vertical profile of the beam permit to characterize the negative ion beam properties in relation to the source parameters. Different methods of H α spectra analysis are here taken into account and compared for the estimation of the beam divergence and the amount of stripping. In particular, to thoroughly study the effect of the space charge compensation on the beam divergence, an additional hydrogen injection line has been added in the tank, which allows for setting different background pressure values (one order of magnitude, from about 0.04 Pa up to the source pressure) in the beam drift region

An Alternative High Luminosity LHC with Flat Optics and Long-Range Beam-Beam Compensation

CERN Document Server

AUTHOR|(CDS)2070952; Valishev, Aleksander; Shatilov, Dmitry

2015-01-01

In the baseline scenario of the High-Luminosity LHC (HL-LHC), the geometric loss of luminosity in the two high luminosity experiments due to collisions with a large crossing angle is recovered by tilting the bunches in the interaction region with the use of crab cavities. A possible backup scenario would rely on a reduced crossing angle together with flat optics (with different horizontal and vertical β∗ values) for the preservation of luminosity performance. However, the reduction of crossing angle coupled with the flat optics significantly enhances the strength of long-range beam-beam interactions. This paper discusses the possibility to mitigate the long-range beam-beam effects by current bearing wire compensators (or e-lens). We develop a new HL-LHC parameter list and analyze it in terms of integrated luminosity performance as compared to the baseline. Further, we evaluate the operational scenarios using numerical simulations of single-particle dynamics with beam-beam effects.

An Alternative High Luminosity LHC with Flat Optics and Long-Range Beam-Beam Compensation

Energy Technology Data Exchange (ETDEWEB)

Fartoukh, Stephane [CERN; Valishev, Alexander [Fermilab; Shatilov, Dmitry [BINP, Novosibirsk

2015-06-01

In the baseline scenario of the High-Luminosity LHC (HL-LHC), the geometric loss of luminosity in the two high luminosity experiments due to collisions with a large crossing angle is recovered by tilting the bunches in the interaction region with the use of crab cavities. A possible backup scenario would rely on a reduced crossing angle together with flat optics (with different horizontal and vertical $\\beta^{\\ast}$values) for the preservation of luminosity performance. However, the reduction of crossing angle coupled with the flat optics significantly enhances the strength of long-range beam-beam interactions. This paper discusses the possibility to mitigate the long-range beam-beam effects by current bearing wire compensators (or e-lens). We develop a new HL-LHC parameter list and analyze it in terms of integrated luminosity performance as compared to the baseline. Further, we evaluate the operational scenarios using numerical simulations of single-particle dynamics with beam-beam effects.

36 CFR 73.7 - World Heritage nomination process.

Science.gov (United States)

2010-07-01

... inscribed as a World Heritage Site. (j) Who is notified when a U.S. property has been nominated to the World... INTERIOR WORLD HERITAGE CONVENTION § 73.7 World Heritage nomination process. (a) What is the U.S. World... Future U.S. World Heritage nominations) and requests that public and private sources recommend properties...

Energy deposition in the window of the TOTEM Roman pot for the nominal TOTEM run

CERN Document Server

Dimovasili, E

2005-01-01

The TOTEM Roman Pot needs to be protected from possible accidents. One of the most serious accident scenarios is the beam loss during an asynchronous abort dump. In this case of dump failure it is possible that a deflected bunch hits the Roman Pot, causing severe damage to its thin window. This technical note discusses the results of FLUKA Monte Carlo studies that have been performed in order to calculate the energy deposition and the temperature increase in the thin window due to the nominal LHC bunch.

An MCNP-based model of a medical linear accelerator x-ray photon beam.

Science.gov (United States)

Ajaj, F A; Ghassal, N M

2003-09-01

The major components in the x-ray photon beam path of the treatment head of the VARIAN Clinac 2300 EX medical linear accelerator were modeled and simulated using the Monte Carlo N-Particle radiation transport computer code (MCNP). Simulated components include x-ray target, primary conical collimator, x-ray beam flattening filter and secondary collimators. X-ray photon energy spectra and angular distributions were calculated using the model. The x-ray beam emerging from the secondary collimators were scored by considering the total x-ray spectra from the target as the source of x-rays at the target position. The depth dose distribution and dose profiles at different depths and field sizes have been calculated at a nominal operating potential of 6 MV and found to be within acceptable limits. It is concluded that accurate specification of the component dimensions, composition and nominal accelerating potential gives a good assessment of the x-ray energy spectra.

An Approach to the Nominal Predicates in English and Romanian

Directory of Open Access Journals (Sweden)

Nicoleta Florina Mincă

2017-06-01

Full Text Available The paper is meant to be an approach to the use of nominal predicates in English and Romanian. In English there are two kinds of nominal predicates: the nominal predicate proper, concerned with the state or quality of the subject, and the double/complex predicate, which is a rather widespread form in English. In Romanian nominal predicates can be split into two categories: the proper nominal predicate, made up of a predicative and the copula “a fi” and the verbal nominal predicate, made up of a predicative and a lexical and grammatical copula. The predicative achievement within the nominal predicate structure is often similar to the subject achievement.

Beam-based alignment of C-shaped quadrupole magnets

International Nuclear Information System (INIS)

Portmann, G.; Robin, D.

1998-06-01

Many storage rings have implemented a method of finding the positional offset between the electrical center of the beam position monitors (BPM) and the magnetic center of the adjacent quadrupole magnets. The algorithm for accomplishing this is usually based on modulating the current in the quadrupole magnet and finding the beam position that minimizes the orbit perturbation. When the quadrupole magnet is C-shaped, as it is for many light sources, the modulation method can produce an erroneous measurement of the magnetic center in the horizontal plane. When the current in a C-shaped quadrupole is changed, there is an additional dipole component in the vertical field. Due to nonlinearities in the hysteresis cycle of the C-magnet geometry, the beam-based alignment technique at the Advanced Light Source (ALS) deviated horizontally by .5 mm from the actual magnetic center. By modifying the technique, the offsets were measured to an accuracy of better than 50 microm

Experience with Kicker Beam Coupling Reduction Techniques

CERN Document Server

Gaxiola, Enrique; Caspers, Friedhelm; Ducimetière, Laurent; Kroyer, Tom

2005-01-01

SPS beam impedance is still one of the worries for operation with nominal LHC beam over longer periods, once the final configuration will be installed in 2006. Several CERN SPS kickers suffer from significant beam induced ferrite heating. In specific cases, for instance beam scrubbing, the temperature of certain ferrite yokes went beyond the Curie point. Several retrofit impedance reduction techniques have been investigated theoretically and with practical tests. We report on experience gained during the 2004 SPS operation with resistively coated ceramic inserts in terms of kicker heating, pulse rise time, operating voltage, and vacuum behaviour. For another technique using interleaved metallic stripes we observed significant improvements in bench measurements. Advantages and drawbacks of both methods and potential combinations of them are discussed and simulation as well as measured data are shown. Prospects for further improvements beyond 2006 are briefly outlined.

Desing and construction of a horizontally placed superconducting magnet and its cryostat for an electron beam ion source

International Nuclear Information System (INIS)

Kobayashi, N.; Ohtani, S.; Kaneko, Y.; Iwai, T.; Okuno, K.

1981-03-01

An electron beam ion source nicknamed NICE-I (Naked Ion Collision Experiments) has been constructed at IPP for studies of atomic processes in fusion plasmas. A super conducting magnet is adopted to generate a strong, stable and homogenious magnetic field to compress a high density electron beam. The solenoid is 1 m long, the inner diameter is 100 mm and the maximum magnetic field is 2T. It is placed horizontally and coaxially with a liquid nitrogen (L-N 2 ) reservoir and a vaccum vessel. In order to fix their axes inmovable even when the reservoirs are cooled by L-N 2 and He, a structure having spokes strained uniformly like a wheel is used between the vaccum vessel and the L-N 2 reservoir and also between the L-N 2 reservoir and the solenoid bore. The electrodes, such as the electron gun, the drift tubes and so on, are mounted on the radiation shields fixed on the L-N 2 reservoir, and they are centered to the solenoid bore within the precision of 0.1 mm. The evapolation rate of L-He is about 1.4 l/h, which is not so much larger than the estimated value. This provides a continuous operation for 16 hours with a charge of 50 l L-He including the precooling of the reservoir. The ultimate pressure 4 x 10 -10 Torr is achived in the vacuum vessel, and the residual gas pressure in the ionization region is expected to be much lower than 1 x 10 -10 Torr. The consideration for mechanical strength and the heat conduction of the materials related to the design are described as well as the details of the structure. (author)

Photon beam position monitor

Science.gov (United States)

Kuzay, Tuncer M.; Shu, Deming

1995-01-01

A photon beam position monitor for use in the front end of a beamline of a high heat flux and high energy photon source such as a synchrotron radiation storage ring detects and measures the position and, when a pair of such monitors are used in tandem, the slope of a photon beam emanating from an insertion device such as a wiggler or an undulator inserted in the straight sections of the ring. The photon beam position monitor includes a plurality of spaced blades for precisely locating the photon beam, with each blade comprised of chemical vapor deposition (CVD) diamond with an outer metal coating of a photon sensitive metal such as tungsten, molybdenum, etc., which combination emits electrons when a high energy photon beam is incident upon the blade. Two such monitors are contemplated for use in the front end of the beamline, with the two monitors having vertically and horizontally offset detector blades to avoid blade "shadowing". Provision is made for aligning the detector blades with the photon beam and limiting detector blade temperature during operation.

Electron beam characteristics on a Philips SL25

International Nuclear Information System (INIS)

Palta, J.R.; Daftari, I.K.; Ayyangar, K.M.; Suntharalingam, N.

1990-01-01

Dosimetry measurements at nominal electron energies of 4, 6, 8, 10, 12, 15, 17, 20, and 22 MeV were made for different sized, open-sided applicators on two Philips SL25 linear accelerators. Measurements include beam flatness, percentage depth dose, surface dose, isodose curves, field size dependence, output at extended distances, virtual source position, and required low melting point alloy thickness for field shaping. These measurements are presented to document the characteristics of electron beams with a new type of applicator design on this series of Philips accelerators

Beam based alignment at the KEK accelerator test facility

International Nuclear Information System (INIS)

Ross, M.; Nelson, J.; Woodley, M.; Wolski, A.

2002-01-01

The KEK Accelerator Test Facility (ATF) damping ring is a prototype low emittance source for the NLC/JLC linear collider. To achieve the goal normalized vertical emittance gey = 20 nm-rad, magnet placement accuracy better than 30 mm must be achieved. Accurate beam-based alignment (BBA) is required. The ATF arc optics uses a FOBO cell with two horizontally focusing quadrupoles, two sextupoles and a horizontally defocusing gradient dipole, all of which must be aligned with BBA. BBA at ATF uses the quadrupole and sextupole trim windings to find the trajectory through the center of each magnet. The results can be interpreted to assess the accuracy of the mechanical alignment and the beam position monitor offsets

Measurement of an electron-beam size with a beam profile monitor using Fresnel zone plates

International Nuclear Information System (INIS)

Iida, K.; Nakamura, N.; Sakai, H.; Shinoe, K.; Takaki, H.; Fujisawa, M.; Hayano, H.; Nomura, M.; Kamiya, Y.; Koseki, T.; Amemiya, Y.; Aoki, N.; Nakayama, K.

2003-01-01

We present a non-destructive and real-time beam profile monitor using Fresnel zone plates (FZPs) and the measurement of an electron-beam size with this monitor in the KEK-Accelerator Test Facility (ATF) damping ring. The monitor system has the structure of a long-distance X-ray microscope, where two FZPs constitute an X-ray imaging optics. The synchrotron radiation from the electron beam at the bending magnet is monochromatized by a crystal monochromator and the transverse electron beam image is twenty times magnified by the two FZPs and detected on an X-ray CCD camera. The expected spatial resolution for the selected photon energy of 3.235 keV is sufficiently high to measure the horizontal and vertical beam sizes of the ATF damping ring. With the beam profile monitor, we succeeded in obtaining a clear electron-beam image and measuring the extremely small beam size less than 10 μm. The measured magnification of the X-ray imaging optics in the monitor system was in good agreement with the design value

Candidate nomination, intra-party democracy, and election violence in Africa

DEFF Research Database (Denmark)

Seeberg, Merete Bech; Wahman, Michael; Skaaning, Svend-Erik

2018-01-01

This article introduces a special issue on candidate nomination, intra-party democracy, and election violence in Africa. Although a burgeoning literature on African democratization has focused on the topic of electoral violence, little attention has been given to violence during party nominations...... of the involvement of electoral management bodies and external monitors, and violence often results. Rather than developing an elaborate theoretical framework on the causes of nomination violence, our ambition in this introduction is to introduce the concept of nomination violence and situate it in the literatures...... on intra-party democracy and election violence. We also offer new descriptive data on nomination rules and nomination violence across parties on the African continent. The data show that nomination violence is a prevalent problem across both democracies and electoral autocracies. However, the level...

Achievement and Evaluation of the Beam Vacuum Performance of the LHC Long Straight Sections

CERN Document Server

Bregliozzi, G; Blanchard, S; Hansen, J; Jiménez, J M; Weiss, K

2008-01-01

The bake-out and activation of the TiZrV NEG coatings of the 6 km Long Straight Sections (LSS) of the Large Hadron Collider (LHC) is in its final step. After the bakeout and the NEG activation, the average ultimate pressure, over more than one hundred vacuum sectors, is below 10^-10 Pa. Therefore, the nominal requirement for the four experimental insertions is fulfilled. The nominal performances are also ensured for all the insertions housing the collimator systems, the RF cavities and the beam dumping systems. The main difficulties encountered during the bake-out and the activation of the NEG coated chambers is presented and discussed. In particular, the acceptance test and the limiting factors of the reached ultimate pressures are addressed. Furthermore, the influence on the ultimate pressures of the beam components (collimators, beam instrumentation, etc.) is discussed. Finally, preliminary results obtained from a NEG vacuum pilot sector installed in the laboratory and dedicated to the evaluation of the NE...

Compensation of the open-quotes Pacmanclose quotes tune spread by tailoring the beam current

International Nuclear Information System (INIS)

Furman, M.A.

1995-04-01

' Factory'-like e + -e - colliders presently under design or construction achieve high luminosity by resorting to large numbers of closely-spaced bunches. The short bunch spacing implies that there are unavoidable parasitic collisions (PCs) in the neighborhood of the interaction point (IP). Since the bunch population of the beam is not uniform due to an intentional ion-clearing gap, the bunches at the head or tail of the train (open-quotes pacman bunchesclose quotes) experience different beam-beam tune shifts than those away from the edges (open-quotes typical bunchesclose quotes). The author presents here a method to minimize the vertical tune spread at the expense of increasing the horizontal tune spread (it is assumed that there is only one IP). Since the beam-beam dynamics for flat beams typically tolerates a significantly higher horizontal tune spread than a vertical tune spread, this method implies a net advantage. The author presents this discussion in the context of the PEP-II collider

STOCK PRICES, 1900-1995: THE REAL AND NOMINAL STORY

Directory of Open Access Journals (Sweden)

Kenneth Weiher

2000-01-01

Full Text Available Prompted by the inflation-adjusted Dow Jones Industrials Average setting its first record high in almost thirty years in 1995, this paper studies the impact of inflation on nominal and real stock prices from a theoretical, historical, and empirical perspective. While stocks are an excellent longterm hedge against inflation, nominal stock prices stagnate and real stock prices fall during a period of rapid inflation. Both nominal and real stockprices then go through a catch-up phase during the subsequent disinflation period. The history for this century is consistent with this pattern. Regression analysis between real and nominal stock prices as the dependent variables and inflation as the independent variable shows statistically significant evidence that (a nominal stock returns are positively related to inflation while real stock returns are not; and (b both nominal and real stock returns are negatively related to accelerations of inflation and positively related to decelerations.

Measurement scheme of kicker impedances via beam-induced voltages of coaxial cables

Energy Technology Data Exchange (ETDEWEB)

Shobuda, Yoshihiro, E-mail: yoshihiro.shobuda@j-parc.jp [J-PARC Center, JAEA and KEK, 2-4 Shirakata Shirane, Tokaimura, Nakagun, Ibaraki 319-1195 (Japan); Irie, Yoshiro [KEK, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Toyama, Takeshi; Kamiya, Junichiro [J-PARC Center, JAEA and KEK, 2-4 Shirakata Shirane, Tokaimura, Nakagun, Ibaraki 319-1195 (Japan); Watanabe, Masao [Ministry of Education, Culture, Sports, Science and Technology, 3-2-2 Kasumigaseki, Chiyoda, Tokyo 100-8959 (Japan)

2013-06-11

A new theory, which satisfies the causality condition, is developed to describe impedances of kicker magnets with coaxial cables. The theoretical results well describe measurement results, which are obtained by standard wire methods. On the other hand, when beams pass through the kicker, voltages are induced at the terminals of coaxial cables. In other words, by analyzing the voltages, the kicker impedance for the beams can be obtained. The observed impedances are consistent with the theoretical results. The theory describes the impedance for non-relativistic beams, as well. The theoretical, simulation and measurement results indicate that the horizontal kicker impedance is drastically reduced by the non-relativistic effect. -- Highlights: ► We develop an innovative method to measure kicker impedance including power cable. ► By analyzing voltages at the ends of coaxial cables, the impedance is derived. ► The horizontal impedance is reduced as the beam becomes non-relativistic.

Slow beam raster system at CEBAF

International Nuclear Information System (INIS)

Yan, C.; Beaufait, J.; Carlini, R.; Cuevas, C.; Vulcan, W.; Wines, R.

1994-01-01

A bedstead air-core raster magnet is being installed now, it will be used at CEBAF to scan the beam on the Hall C polarized target and the beam dump with fixed frequency 60 Hz in horizontal, 103.4 Hz in vertical. The x and y raster magnets are driven by Variac transformer and SUMIT-OMO inverter respectively. Both of them provide an approximate sine current waveform with peak current 20 A, corresponding to a maximum deflection angle 1 mr

LHC Damper Beam commissioning in 2010

CERN Document Server

Höfle, W; Schokker, M; Valuch, D

2011-01-01

The LHC transverse dampers were commissioned in 2010 with beam and their use at injection energy of 450 GeV, during the ramp and in collisions at 3.5 TeV for Physics has become part of the standard operations pro- cedure. The system proved important to limit emittance blow-up at injection and to maintain smaller than nominal emittances throughout the accelerating cycle. We describe the commissioning of the system step-by-step as done in 2010 and summarize its performance as achieved for pro- ton as well as ion beams in 2010. Although its principle function is to keep transverse oscillations under control, the system has also been used as an exciter for abort gap clean- ing and tune measurement. The dedicated beam position measurement system with its low noise properties provides additional possibilities for diagnostics.

Beam-beam effects in high energy e+e- storage rings: resonant amplification of vertical dimensions for flat beams

International Nuclear Information System (INIS)

Bambade, P.

1984-06-01

In this thesis, we present a phenomenological study of the beam-beam effect in e + e - storage rings. We are in particular interested in the blow-up of the vertical dimension observed in this kind of accelerator. A detailed analysis of the electromagnetic field generated by the very flat bunches stored, and seen by the counter-rotating particles shows that two-dimensional non-linear resonances, which couple vertical and horizontal betatron oscillations, play a very important role. Moreover, the ''weak beam-strong beam'' approximation holds rather well in the case of very flat bunches. Perturbative analysis enables us to predict the effects from the strongest coupling resonance: 20sub(x)-20sub(y) = integer. We find that mainly the tails of the vertical distribution are affected, and we give a criterion concerning the optimal distance to this resonance in the case of a storage ring such as LEP. Finally, the results and in particular the validity of the single resonance approximation are checked through a numerical simulation [fr

Surface-induced errors in target strength and position estimates during horizontal acoustic surveys

Czech Academy of Sciences Publication Activity Database

Balk, Helge; Sovegjarto, B.S.; Tušer, Michal; Frouzová, Jaroslava; Muška, Milan; Draštík, Vladislav; Baran, Roman; Kubečka, Jan

2017-01-01

Roč. 188, APR (2017), s. 149-156 ISSN 0165-7836 R&D Projects: GA MŠk(CZ) EE2.3.20.0204; GA ČR GAP504/12/1186 Institutional support: RVO:60077344 Keywords : hydroacoustics * surface boundary * shallow water * horizontal beaming * simulations Subject RIV: GL - Fish ing OBOR OECD: Fish ery Impact factor: 2.185, year: 2016

The source of real and nominal exchange rate fluctuations in Thailand: Real shock or nominal shock

OpenAIRE

Le Thanh, Binh

2015-01-01

This paper examines the source of exchange rate fluctuations in Thailand. We employed a structural vector auto-regression (SVAR) model with the long-run neutrality restriction of Blanchard and Quah (1989) to investigate the changes in real and nominal exchange rates from 1994 to 2015. In this paper, we assume that there are two types of shocks which related to exchange rate movements: real shocks and nominal shocks. The empirical analysis indicates that real shocks are the fundamental compon...

Longitudinal beam parameters and quality checks of the LHC beam in the SPS: further results and comparisons

CERN Document Server

Papotti, G; Linnecar, T; Shaposhnikova, E; Tückmantel, Joachim; CERN. Geneva. AB Department

2008-01-01

Controlled longitudinal emittance blow up is used, along with other measures, to stabilize the nominal LHC beam in the SPS. Two Machine Development studies (MDs) were carried out in 2007 to evaluate the effectiveness of different noise settings for the longitudinal blow up of the beam. The noise settings are affected by both the presence of the 800 MHz RF system and intensity effects which modify the synchrotron frequency distribution inside the bunch. The results for the first MD are reported in Note [1]. This Note reports on the results of the second MD, carried out on 2007-10-17, as well as the comparison between the two in order to analyse the differences between the two occasions. Figures of merit are used that allow rapid evaluation of the quality of the beam as for example stability and bunch length uniformity across batches.

Beam induced hydrodynamic tunneling in the future circular collider components

Directory of Open Access Journals (Sweden)

N. A. Tahir

2016-08-01

Full Text Available A future circular collider (FCC has been proposed as a post-Large Hadron Collider accelerator, to explore particle physics in unprecedented energy ranges. The FCC is a circular collider in a tunnel with a circumference of 80–100 km. The FCC study puts an emphasis on proton-proton high-energy and electron-positron high-intensity frontier machines. A proton-electron interaction scenario is also examined. According to the nominal FCC parameters, each of the 50 TeV proton beams will carry an amount of 8.5 GJ energy that is equivalent to the kinetic energy of an Airbus A380 (560 t at a typical speed of 850  km/h. Safety of operation with such extremely energetic beams is an important issue, as off-nominal beam loss can cause serious damage to the accelerator and detector components with a severe impact on the accelerator environment. In order to estimate the consequences of an accident with the full beam accidently deflected into equipment, we have carried out numerical simulations of interaction of a FCC beam with a solid copper target using an energy-deposition code (fluka and a 2D hydrodynamic code (big2 iteratively. These simulations show that, although the penetration length of a single FCC proton and its shower in solid copper is about 1.5 m, the full FCC beam will penetrate up to about 350 m into the target because of the “hydrodynamic tunneling.” These simulations also show that a significant part of the target is converted into high-energy-density matter. We also discuss this interesting aspect of this study.

Beam Induced Hydrodynamic Tunneling in the Future Circular Collider Components

Science.gov (United States)

Tahir, N. A.; Burkart, F.; Schmidt, R.; Shutov, A.; Wollmann, D.; Piriz, A. R.

2016-08-01

A future circular collider (FCC) has been proposed as a post-Large Hadron Collider accelerator, to explore particle physics in unprecedented energy ranges. The FCC is a circular collider in a tunnel with a circumference of 80-100 km. The FCC study puts an emphasis on proton-proton high-energy and electron-positron high-intensity frontier machines. A proton-electron interaction scenario is also examined. According to the nominal FCC parameters, each of the 50 TeV proton beams will carry an amount of 8.5 GJ energy that is equivalent to the kinetic energy of an Airbus A380 (560 t) at a typical speed of 850 km /h . Safety of operation with such extremely energetic beams is an important issue, as off-nominal beam loss can cause serious damage to the accelerator and detector components with a severe impact on the accelerator environment. In order to estimate the consequences of an accident with the full beam accidently deflected into equipment, we have carried out numerical simulations of interaction of a FCC beam with a solid copper target using an energy-deposition code (fluka) and a 2D hydrodynamic code (big2) iteratively. These simulations show that, although the penetration length of a single FCC proton and its shower in solid copper is about 1.5 m, the full FCC beam will penetrate up to about 350 m into the target because of the "hydrodynamic tunneling." These simulations also show that a significant part of the target is converted into high-energy-density matter. We also discuss this interesting aspect of this study.

A redundancy-removing feature selection algorithm for nominal data

Directory of Open Access Journals (Sweden)

Zhihua Li

2015-10-01

Full Text Available No order correlation or similarity metric exists in nominal data, and there will always be more redundancy in a nominal dataset, which means that an efficient mutual information-based nominal-data feature selection method is relatively difficult to find. In this paper, a nominal-data feature selection method based on mutual information without data transformation, called the redundancy-removing more relevance less redundancy algorithm, is proposed. By forming several new information-related definitions and the corresponding computational methods, the proposed method can compute the information-related amount of nominal data directly. Furthermore, by creating a new evaluation function that considers both the relevance and the redundancy globally, the new feature selection method can evaluate the importance of each nominal-data feature. Although the presented feature selection method takes commonly used MIFS-like forms, it is capable of handling high-dimensional datasets without expensive computations. We perform extensive experimental comparisons of the proposed algorithm and other methods using three benchmarking nominal datasets with two different classifiers. The experimental results demonstrate the average advantage of the presented algorithm over the well-known NMIFS algorithm in terms of the feature selection and classification accuracy, which indicates that the proposed method has a promising performance.

24 CFR 597.202 - Submission of nominations for designation.

Science.gov (United States)

2010-04-01

... nominated urban area satisfies the poverty rate tests set forth in § 597.103; (4) The nominated urban area... 24 Housing and Urban Development 3 2010-04-01 2010-04-01 false Submission of nominations for designation. 597.202 Section 597.202 Housing and Urban Development Regulations Relating to Housing and Urban...

Beam losses due to abrupt crab cavity failures in the LHC

International Nuclear Information System (INIS)

Baer, T.; Barranco, J.; Calaga, R.; Tomas, R.; Wenninger, B.; Yee, B.; Zimmermann, F.

2011-01-01

A major concern for the implementation of crab crossing in a future High-Luminosity LHC (HL-LHC) is machine protection in an event of a fast crab-cavity failure. Certain types of abrupt crab-cavity amplitude and phase changes are simulated to characterize the effect of failures on the beam and the resulting particle-loss signatures. The time-dependent beam loss distributions around the ring and particle trajectories obtained from the simulations allow for a first assessment of the resulting beam impact on LHC collimators and on sensitive components around the ring. Results for the nominal LHC lattice is presented.

Dual deflectable beam strip engine development.

Science.gov (United States)

Dulgeroff, C. R.; Zuccaro, D. E.; Kami, S.; Schnelker, D. E.; Ward, J. W.

1972-01-01

This paper describes a dual beam thruster that has been designed, constructed, and tested. The system is suitable for two-axes attitude control and is comprised of two orthogonal strips, each capable of producing 0.30 mlb thrust and beam deflections of more than plus or minus 20 deg. The nominal specific impulse for the thruster is 5000 sec, and the thrust level from each strip can be varied from 0 to 100%. Neutralizer filaments that were developed and life tested over 2000 hours producing more than 40 mA of electron emission per watt of input power are also discussed. The system power required for clean ionizers is approximately 200 W.

Disruption effects on the beam size measurement

Energy Technology Data Exchange (ETDEWEB)

Raimondi, P.; Decker, F.J.; Chen, P.

1995-06-01

At the SLC Final Focus with higher currents and smaller beam sizes, the disruption parameter D{sub y} is close to one and so the pinch effect should produce a luminosity enhancement. Since a flat beam-beam function is fit to deflection scan data to measure the beam size, disruption can affect the measurement. Here the authors discuss the quantitative effects of disruption for typical SLC beam parameters. With 3.5 10{sup 10} particles per pulse, bunch length of 0.8 mm and beam sizes of 2.1 {mu}m horizontally and 0.55 {mu}m vertically, the measured vertical size can be as much as 25% bigger than the real one. Furthermore during the collision the spot size actually decrease, producing an enhancement factor H{sub D} of about 1.25. This would yield to a true luminosity which is 1.6 times that which is estimated from the beam-beam deflection fit.

Disruption effects on the beam size measurement

International Nuclear Information System (INIS)

Raimondi, P.; Decker, F.J.; Chen, P.

1995-01-01

At the SLC Final Focus with higher currents and smaller beam sizes, the disruption parameter D y is close to one and so the pinch effect should produce a luminosity enhancement. Since a flat beam-beam function is fit to deflection scan data to measure the beam size, disruption can affect the measurement. Here the authors discuss the quantitative effects of disruption for typical SLC beam parameters. With 3.5 10 10 particles per pulse, bunch length of 0.8 mm and beam sizes of 2.1 μm horizontally and 0.55 μm vertically, the measured vertical size can be as much as 25% bigger than the real one. Furthermore during the collision the spot size actually decrease, producing an enhancement factor H D of about 1.25. This would yield to a true luminosity which is 1.6 times that which is estimated from the beam-beam deflection fit

Preparation of the beam for PS-MTE at the PSB

CERN Document Server

Chanel, M; CERN. Geneva. BE Department

2009-01-01

The Multi-Turn Extraction(MTE)1 at the PS requires, from the PSB, a beam(up to 6.5 1012 protons/ring) with a large horizontal emittance to better produce the five beamlets and a vertical emittance as small as possible. The ways to produce this beam and adjust the parameters are described in this note.

Dosimetric consequences of pencil beam width variations in scanned beam particle therapy

International Nuclear Information System (INIS)

Chanrion, M A; Ammazzalorso, F; Wittig, A; Engenhart-Cabillic, R; Jelen, U

2013-01-01

Scanned ion beam delivery enables the highest degree of target dose conformation attainable in external beam radiotherapy. Nominal pencil beam widths (spot sizes) are recorded during treatment planning system commissioning. Due to changes in the beam-line optics, the actual spot sizes may differ from these commissioning values, leading to differences between planned and delivered dose. The purpose of this study was to analyse the dosimetric consequences of spot size variations in particle therapy treatment plans. For 12 patients with skull base tumours and 12 patients with prostate carcinoma, scanned-beam carbon ion and proton treatment plans were prepared and recomputed simulating spot size changes of (1) ±10% to simulate the typical magnitude of fluctuations, (2) ±25% representing the worst-case scenario and (3) ±50% as a part of a risk analysis in case of fault conditions. The primary effect of the spot size variation was a dose deterioration affecting the target edge: loss of target coverage and broadening of the lateral penumbra (increased spot size) or overdosage and contraction of the lateral penumbra (reduced spot size). For changes ⩽25%, the resulting planning target volume mean 95%-isodose line coverage (CI-95%) deterioration was ranging from negligible to moderate. In some cases changes in the dose to adjoining critical structures were observed. (paper)

Nominalized clauses, clausal arguments and agreement

OpenAIRE

Picallo, M. Carme

2001-01-01

Strict minimalist assumptions require adopting the hypothesis that argument clauses and nominalized clauses are assigned Phi features. The data examined suggest that the interpretable Phi content of these arguments is specified as [-P, -N, -G]. We conclude that all arguments (of the clausal or of the nominal types) are subject to the operation Agree with a functional category. All arguments behave alike as far as abstract computational operations is concerned. The computational component is b...

Deflection system for charged-particle beam

Energy Technology Data Exchange (ETDEWEB)

Bates, T

1982-01-13

A system is described for achromatically deflecting a beam of charged particles without producing net divergence of the beam comprising three successive magnetic deflection means which deflect the beam alternately in opposite directions; the first and second deflect by angles of less than 50/sup 0/ and the third by an angle of at least 90/sup 0/. Particles with different respective energies are transversely spaced as they enter the third deflection means, but emerge completely superimposed in both position and direction and may be brought to a focus in each of two mutually perpendicular planes, a short distance thereafter. Such a system may be particularly compact, especially in the direction in which the beam leaves the system. It is suitable for deflecting a beam of electrons from a linear accelerator so producing a vertical beam of electron (or with an X-ray target, of X-rays) which can be rotated about a horizontal patient for radiation therapy.

Nominalizations in Spanish. Studies in Linguistics and Language Learning, Volume V.

Science.gov (United States)

Falk, Julia Sableski

Using methods developed in transformational generative grammar, three types of nominal constructions in Spanish are treated in this paper: Fact nominalizations ("[El] Escribir es agradable"), Manner nominalizations ("El tocar [de la mujer] es agradable"), and Abstract noun nominalizations ("La construccion rapida de esta escuela es dudosa"). While…

Demonstration of two-beam acceleration in CTF II

CERN Document Server

Bossart, Rudolf; Carron, G; Chanudet, M; Chautard, F; Delahaye, J P; Godot, J C; Hutchins, S; Kamber, I; Martínez, C; Suberlucq, Guy; Tenenbaum, P G; Thorndahl, L; Valentini, M; Wilson, Ian H; Wuensch, Walter

1999-01-01

The second phase of the Compact LInear Collider (CLIC) Test Facility (CTF II) at CERN has demon-strated the feasibility of two-beam acceleration at 30 GHz using a high-charge drive beam, running paral lel to the main beam, as the RF power source. To date accelerating gradients of 59 MV/m at 30 GHz have been achieved. In CTF II, the two beams are generated by 3 GHz RF photo-injectors and are acceler ated in 3 GHz linacs, before injection into the 30 GHz modules. The drive beam linac has to accelerate a 16 ns long train of 48 bunches, each with a nominal charge of 13.4 nC. To cope with the very su bstantial beam-loading special accelerating structures are used (running slightly off the bunch repetition frequency). A magnetic chicane compresses the bunches to less than 5 ps fwhm, this is needed for efficient 30 GHz power generation. The 30 GHz modules are fully-engineered representative sections of CLIC, they include a 30 GHz decelerator for the drive beam, a 30 GHz accelerator for the main beam, high resolution...

Ferrofluid meniscus in a horizontal or vertical magnetic field

International Nuclear Information System (INIS)

Rosensweig, R.E.; Elborai, S.; Lee, S.-H.; Zahn, M.

2005-01-01

An optical system using reflections of a narrow laser beam to measure the height and shape of a ferrofluid meniscus in response to uniform applied magnetic fields finds that meniscus height on a vertical flat wall decreases in horizontal applied field and increases in vertical applied field. An approximate energy minimization analysis predicts meniscus height in directional agreement with measurements. This study is a first step in calculating the tangential surface force acting in flows where magnetization magnitude and direction lag a changing magnetic field direction, and the meniscus shape is magnetically perturbed

In RC buildings, the vertical and horizontal members (ie, the beams ...

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 10; Issue 4. Learning Earthquake Design and Construction - 18. How do Beams in RC Buildings Resist Earthquakes? C V R Murty. Classroom Volume 10 Issue 4 April 2005 pp 87-90 ...

Neutral beam injection system design for KSTAR tokamak

Energy Technology Data Exchange (ETDEWEB)

Choi, B.H.; Lee, K.W.; Chung, K.S.; Oh, B.H.; Cho, Y.S.; Bae, Y.D.; Han, J.M. [Korea Atomic Energy Research Institute, Taejon (Korea)

1998-06-01

The NBI system for KSTAR (Korean Superconducting Tokamak Advanced Research) has been designed based on conventional positive ion beam technology. One beam line consists of three ion sources, three neutralizers, one bending magnet, and one drift tube. This system will deliver 8 MW deuterium beam to KSTAR plasma in normal operation to support the advanced experiments on heating, current drive and profile control. The key technical issues in this design were high power ion source(120 kV, 65 A), long pulse operation (300 seconds; world record is 30 sec), and beam rotation from vertical to horizontal direction. The suggested important R and D points on ion source and beam line components are also included. (author). 7 refs., 27 figs., 1 tab.

Steel septum magnets for the LHC beam injection and extraction

CERN Document Server

Bidon, S; Guinand, M; Gyr, Marcel; Sassowsky, M; Weisse, E; Weterings, W; Abramov, A; Ivanenko, A I; Kolatcheva, E; Lapyguina, O; Ludmirsky, E; Mishina, N; Podlesny, P; Riabov, A; Tyurin, N

2002-01-01

The Large Hadron Collider (LHC) will be a superconducting accelerator and collider to be installed in the existing underground LEP ring tunnel at CERN. It will provide proton-proton collisions with a centre of mass energy of 14 TeV. The proton beams coming from the SPS will be injected into the LHC at 450 GeV by vertically deflecting kicker magnets and horizontally deflecting steel septum magnets (MSI). The proton beams will be dumped from the LHC with the help of two extraction systems comprising horizontally deflecting kicker magnets and vertically deflecting steel septum magnets (MSD). The MSI and MSD septa are laminated iron-dominated magnets using an all welded construction. The yokes are constructed from two different half cores, called coil core and septum core. The septum cores comprise circular holes for the circulating beams. This avoids the need for careful alignment of the usually wedge-shaped septum blades used in classical Lambertson magnets. The MSI and MSD septum magnets were designed and buil...

Beam tomography or ART in accelerator physics

International Nuclear Information System (INIS)

Fraser, J.S.

1978-11-01

Projections of charged particle beam current density have been used for many years as a measure of beam position and size. The conventional practice of obtaining only two projections, usually in the horizontal and vertical planes, puts a severe limit on the detail that can be recovered from the projections. A third projection provides sufficient improvement to justify the addition of a wire to the conventional wire scanner in certain cases. A group of programs using algebraic reconstruction techniques was written to reconstruct beam current density from beam projections obtained at three or more specific or arbitrary angles around the beam. A generalized program, which makes use of arbitrary 2 x 2 transfer matrices between projections, can be used to reconstruct transverse or longitudinal emittance from appropriate projections. Reconstruction examples of beam current density and transverse and longitudinal emittance using experimental data from the Clinton P. Anderson Meson Physics Facility (LAMPF) accelerator beam are given

Fixed target beams

CERN Document Server

Kain, V; Cettour-Cave, S; Cornelis, K; Fraser, M A; Gatignon, L; Goddard, B; Velotti, F

2017-01-01

The CERN SPS (Super Proton Synchrotron) serves asLHC injector and provides beam for the North Area fixedtarget experiments. At low energy, the vertical acceptancebecomes critical with high intensity large emittance fixed tar-get beams. Optimizing the vertical available aperture is a keyingredient to optimize transmission and reduce activationaround the ring. During the 2016 run a tool was developed toprovide an automated local aperture scan around the entirering.The flux of particles slow extracted with the1/3inte-ger resonance from the Super Proton Synchrotron at CERNshould ideally be constant over the length of the extractionplateau, for optimum use of the beam by the fixed target ex-periments in the North Area. The extracted intensity is con-trolled in feed-forward correction of the horizontal tune viathe main SPS quadrupoles. The Mains power supply noiseat 50 Hz and harmonics is also corrected in feed-forwardby small amplitude tune modulation at the respective fre-quencies with a dedicated additional quad...

Flying wire beam profile monitor at the J-PARC MR

International Nuclear Information System (INIS)

Igarashi, Susumu; Arakawa, Dai; Hashimoto, Yoshinori; Teshima, Masaki; Toyama, Takeshi; Hanamura, Kotoku

2008-01-01

A flying wire beam profile monitor has been assembled and installed at the main ring of the Japan Proton Accelerator Research Complex. The monitor is to measure the horizontal beam profile using a carbon fiber of 7 μmφ. The fiber crosses the beam with the speed of 10 m/s. Secondary particles from the beam-wire scattering is detected using a scintillation counter. The scintillator signal as a function of the wire position is to be reconstructed as a beam profile. The high scanning speed and the minimum material are necessary for the accurate beam profile measurement. The monitor has been operated in the beam commissioning run of the main ring. The beam profile data have been successfully acquired after the reduction of the beam background. (author)

Biaxial nominal state of stress at the crack front

International Nuclear Information System (INIS)

Dietmann, H.; Kussmaul, K.

1979-01-01

In fracture toughness testing with CT-specimens there is an unaxial nominal stress state caused by the nominal stress psub(y) perpendicular to the crack surface. This paper investigates the question whether the fracture toughness, or generally speaking, the fracture load, is influenced by additional nominal stresses psub(x) and psub(z) in the crack surface, i.e. by a multiaxial stress state. (orig.)

An embeddable optical strain gauge based on a buckled beam.

Science.gov (United States)

Du, Yang; Chen, Yizheng; Zhu, Chen; Zhuang, Yiyang; Huang, Jie

2017-11-01

We report, for the first time, a low cost, compact, and novel mechanically designed extrinsic Fabry-Perot interferometer (EFPI)-based optical fiber sensor with a strain amplification mechanism for strain measurement. The fundamental design principle includes a buckled beam with a coated gold layer, mounted on two grips. A Fabry-Perot cavity is produced between the buckled beam and the endface of a single mode fiber (SMF). A ceramic ferrule is applied for supporting and orienting the SMF. The principal sensor elements are packaged and protected by two designed metal shells. The midpoint of the buckled beam will experience a deflection vertically when the beam is subjected to a horizontally/axially compressive displacement. It has been found that the vertical deflection of the beam at midpoint can be 6-17 times larger than the horizontal/axial displacement, which forms the basis of a strain amplification mechanism. The user-configurable buckling beam geometry-based strain amplification mechanism enables the strain sensor to achieve a wide range of strain measurement sensitivities. The designed EFPI was used to monitor shrinkage of a square brick of mortar. The strain was measured during the drying/curing stage. We envision that it could be a good strain sensor to be embedded in civil materials/structures under a harsh environment for a prolonged period of time.

An embeddable optical strain gauge based on a buckled beam

Science.gov (United States)

Du, Yang; Chen, Yizheng; Zhu, Chen; Zhuang, Yiyang; Huang, Jie

2017-11-01

We report, for the first time, a low cost, compact, and novel mechanically designed extrinsic Fabry-Perot interferometer (EFPI)-based optical fiber sensor with a strain amplification mechanism for strain measurement. The fundamental design principle includes a buckled beam with a coated gold layer, mounted on two grips. A Fabry-Perot cavity is produced between the buckled beam and the endface of a single mode fiber (SMF). A ceramic ferrule is applied for supporting and orienting the SMF. The principal sensor elements are packaged and protected by two designed metal shells. The midpoint of the buckled beam will experience a deflection vertically when the beam is subjected to a horizontally/axially compressive displacement. It has been found that the vertical deflection of the beam at midpoint can be 6-17 times larger than the horizontal/axial displacement, which forms the basis of a strain amplification mechanism. The user-configurable buckling beam geometry-based strain amplification mechanism enables the strain sensor to achieve a wide range of strain measurement sensitivities. The designed EFPI was used to monitor shrinkage of a square brick of mortar. The strain was measured during the drying/curing stage. We envision that it could be a good strain sensor to be embedded in civil materials/structures under a harsh environment for a prolonged period of time.

Technical Note: Using experimentally determined proton spot scanning timing parameters to accurately model beam delivery time.

Science.gov (United States)

Shen, Jiajian; Tryggestad, Erik; Younkin, James E; Keole, Sameer R; Furutani, Keith M; Kang, Yixiu; Herman, Michael G; Bues, Martin

2017-10-01

To accurately model the beam delivery time (BDT) for a synchrotron-based proton spot scanning system using experimentally determined beam parameters. A model to simulate the proton spot delivery sequences was constructed, and BDT was calculated by summing times for layer switch, spot switch, and spot delivery. Test plans were designed to isolate and quantify the relevant beam parameters in the operation cycle of the proton beam therapy delivery system. These parameters included the layer switch time, magnet preparation and verification time, average beam scanning speeds in x- and y-directions, proton spill rate, and maximum charge and maximum extraction time for each spill. The experimentally determined parameters, as well as the nominal values initially provided by the vendor, served as inputs to the model to predict BDTs for 602 clinical proton beam deliveries. The calculated BDTs (T BDT ) were compared with the BDTs recorded in the treatment delivery log files (T Log ): ∆t = T Log -T BDT . The experimentally determined average layer switch time for all 97 energies was 1.91 s (ranging from 1.9 to 2.0 s for beam energies from 71.3 to 228.8 MeV), average magnet preparation and verification time was 1.93 ms, the average scanning speeds were 5.9 m/s in x-direction and 19.3 m/s in y-direction, the proton spill rate was 8.7 MU/s, and the maximum proton charge available for one acceleration is 2.0 ± 0.4 nC. Some of the measured parameters differed from the nominal values provided by the vendor. The calculated BDTs using experimentally determined parameters matched the recorded BDTs of 602 beam deliveries (∆t = -0.49 ± 1.44 s), which were significantly more accurate than BDTs calculated using nominal timing parameters (∆t = -7.48 ± 6.97 s). An accurate model for BDT prediction was achieved by using the experimentally determined proton beam therapy delivery parameters, which may be useful in modeling the interplay effect and patient throughput. The model may

Specialists' meeting on thermodynamics of FBR fuel subassemblies under nominal and non-nominal operating conditions. Summary report

Energy Technology Data Exchange (ETDEWEB)

1979-01-01

The purpose of the meeting was to provide a forum for exchange of information on thermo- and fluiddynamic investigations of LMFBR-subassembly. Special emphasis was placed on nominal and non-nominal conditions. The technical part of the meeting was divided into four sessions, as follows: status of the thermo- and fluiddynamic activities; physical and mathematical modelling of single phase; rod bundle thermohydraulics; experimental investigations; and future R and D. Separate abstracts are included for each of the papers.

Initial Measurements of CSR from a Bunch-Compressed Beam at APS

CERN Document Server

Lumpkin, Alex H; Borland, M; Sereno, N S

2005-01-01

The interest in bunch compression to generate higher peak current electron beams with low emittance continues in the free-electron laser (FEL) community. At the Advanced Photon source (APS) we have both an rf thermionic gun and an rf photocathode (PC) gun on the S-band linac. At the 150-MeV point in the linac, we have a flexible chicane bunch compressor whose four dipoles bend the beam in the horizontal plane. There is also a vertical bend dipole after the chicane that allows measurement of energy and horizontal beam size at the imaging screen station to study possible effects on emittance due to coherent synchrotron radiation (CSR) in the chicane. A far-infrared (FIR) coherent radiation monitor is located downstream of the chicane as well. We have begun recommissioning of this device with coherent transition radiation (CTR), but we also have directly observed CSR from the bunch-compressed beam as it transits the vertical dipole and goes into the down leg. The unique geometry allows simultaneous tracking of b...

Beam Loss Monitoring for LHC Machine Protection

Science.gov (United States)

Holzer, Eva Barbara; Dehning, Bernd; Effnger, Ewald; Emery, Jonathan; Grishin, Viatcheslav; Hajdu, Csaba; Jackson, Stephen; Kurfuerst, Christoph; Marsili, Aurelien; Misiowiec, Marek; Nagel, Markus; Busto, Eduardo Nebot Del; Nordt, Annika; Roderick, Chris; Sapinski, Mariusz; Zamantzas, Christos

The energy stored in the nominal LHC beams is two times 362 MJ, 100 times the energy of the Tevatron. As little as 1 mJ/cm3 deposited energy quenches a magnet at 7 TeV and 1 J/cm3 causes magnet damage. The beam dumps are the only places to safely dispose of this beam. One of the key systems for machine protection is the beam loss monitoring (BLM) system. About 3600 ionization chambers are installed at likely or critical loss locations around the LHC ring. The losses are integrated in 12 time intervals ranging from 40 μs to 84 s and compared to threshold values defined in 32 energy ranges. A beam abort is requested when potentially dangerous losses are detected or when any of the numerous internal system validation tests fails. In addition, loss data are used for machine set-up and operational verifications. The collimation system for example uses the loss data for set-up and regular performance verification. Commissioning and operational experience of the BLM are presented: The machine protection functionality of the BLM system has been fully reliable; the LHC availability has not been compromised by false beam aborts.

Beam-machine Interaction at the CERN LHC

CERN Document Server

Boccone, V; Brugger, M; Calviani, M; Cerutti, F; Esposito, L S; Ferrari, A; Lechner, A; Mereghetti, A; Nowak, E; Shetty, N V; Skordis, E; Versaci, R; Vlachoudis, V

2014-01-01

The radiation field generated by a high energy and intensity accelerator is of concern in terms of element functionality threat, component damage, electronics reliability, and material activation, but also provides signatures that allow actual operating conditions to be monitored. The shower initiated by an energetic hadron involves many different physical processes, down to slow neutron interactions and fragment de-excitation, which need to be accurately described for design purposes and to interpret operation events. The experience with the transport and interaction Monte Carlo code FLUKA at the Large Hadron Collider (LHC), operating at CERN with 4 TeV proton beams (and equivalent magnetic rigidity Pb beams) and approaching nominal luminosity and energy, is presented. Design, operation and upgrade challenges are reviewed in the context of beam-machine interaction account and relevant benchmarking examples based on radiation monitor measurements are shown.

Application of digital beam position processor Libera on tune measurement

International Nuclear Information System (INIS)

Zhang Chunhui; Sun Baogen; Cao Yong; Lu Ping; Li Jihao

2006-01-01

Digital signal processing (DSP) is widely used in the field of beam diagnostics. Especially, DSP achieves very good performance in beam position signal analysis and betatron tune measurement. In Hefei light source, when beam was excited by narrow-band Gaussian white nose, Libera, a digital beam position processor, was used to process the signals from beam position monitor (BPM), which contained betatron oscillation. Fast Fourier transform (FFT) was applied to finding out betatron resonance frequency, from which the decimal part of betatron oscillation tune was calculated. By this means, the measure of horizontal tune was 3.5352 and the measure of vertical tune is 2.6299. (authors)

Overview of magnetic nonlinear beam dynamics in the RHIC

International Nuclear Information System (INIS)

Luo, Y.; Bai, M.; Beebe-Wang, J.; Bengtsson, J.; Calaga, R.; Fischer, W.; Jain, A.; Pilat, F.; Ptitsyn, V.; Malitsky, N.; Robert-Demolaize, G.; Satogata, T.; Tepikian, S.; Tomas, R.; Trbojevic, D.

2009-01-01

In this article we review our studies of nonlinear beam dynamics due to the nonlinear magnetic field errors in the Relativistic Heavy Ion Collider (RHIC). Nonlinear magnetic field errors, including magnetic field errors in interaction regions (IRs), chromatic sextupoles, and sextupole components from arc main dipoles are discussed. Their effects on beam dynamics and beam dynamic aperture are evaluated. The online methods to measure and correct the IR nonlinear field errors, second order chromaticities, and horizontal third order resonance are presented. The overall strategy for nonlinear corrections in RHIC is discussed

Laser beam deflection-based perimeter scanning of integrated circuits for local overheating location

International Nuclear Information System (INIS)

Perpina, X; Jorda, X; Vellvehi, M; Altet, J; Mestres, N

2009-01-01

In integrated circuits, local overheating (hot spots) can be detected by monitoring the temperature gradients present in the silicon substrate at a given depth, laterally accessing the die with an infra-red laser beam probe. The sensed magnitude is the laser beam deflection, which is proportional to the temperature gradients found along the beam trajectory (mirage effect). Biasing the devices with periodic electrical functions allows employing lock-in detection strategies (noise immunity) and thermally isolating the analysed chip substrate thermal behaviour from the external boundary conditions by setting the excitation frequency (control of the thermal energy penetration depth). Measuring the first harmonic of the deflection signal components (vertical and horizontal) allows performing a fast and accurate location of devices, interconnects or circuits dissipating relatively high power levels without any calibration procedure. It has been concluded that the horizontal component of the beam deflection provides a higher spatial resolution than the vertical one when measurements are performed beyond the thermal energy penetration depth. (fast track communication)

Beam Dump Design for the Rare Isotope Accelerator Fragmentation Line

Energy Technology Data Exchange (ETDEWEB)

Stein, W; Ahle, L E; Reyes, S

2006-05-02

Beam dumps for the heavy ion beams of the fragmentation line of the Rare Isotope Accelerator have been designed. The most severe operational case involves a continuous U beam impacting the beam dump with a power of 295 kW and a nominal spot diameter size of 5 cm. The dump mechanically consists of two rotating barrels with a water cooled outer wall of 2 mm thick aluminum. The barrels are 70 cm in diameter and axially long enough to intercept a variety of other beams. The aluminum wall absorbs approximately 15% of the U beam power with the rest absorbed in the water downstream of the wall. The water acts as an absorber of the beam and as a coolant for the 2 mm aluminum wall. The barrel rotates at less than 400 RPM, maximum aluminum temperatures are less than 100 C and maximum thermal fatigue stresses are low at 3.5 x 10{sup 7} Pa (5 ksi). Rotation of the dump results in relatively low radiation damage levels with an operating lifetime of years for most beams.

LHC Report: 1,033 bunches per beam and counting

CERN Multimedia

Jorg Wenninger for the LHC team

2015-01-01

Following the second technical stop, the first beams were injected into the LHC in the early evening of Saturday, 5 September. About ten days later, the machine was operated with around 1,000 bunches per beam.    Evolution of the stored energy per LHC beam, over time.   The first step after a technical stop consists of running through a full LHC cycle, from injection to collisions and beam dump, with a low-intensity bunch (“probe”) to check all machine settings and equipment. This is followed by a series of collimation and absorber validation tests at different points in the LHC cycle. Low-intensity beams – typically the equivalent of three nominal bunches (3 x 1011 protons) – are expanded transversely or longitudinally, or de-bunched to verify that the collimators and absorbers are correctly intercepting lost particles. The techniques for those validations have been progressively improved, and t...

Bunched beam neutralization

International Nuclear Information System (INIS)

Gammel, G.M.; Maschke, A.W.; Mobley, R.M.

1979-01-01

One of the steps involved in producing an intense ion beam from conventional accelerators for Heavy Ion Fusion (HIF) is beam bunching. To maintain space charge neutralized transport, neutralization must occur more quickly as the beam bunches. It has been demonstrated at BNL that a 60 mA proton beam from a 750 kV Cockcroft--Walton can be neutralized within a microsecond. The special problem in HIF is that the neutralization must occur in a time scale of nanoseconds. To study neutralization on a faster time scale, a 40 mA, 450 kV proton beam was bunched at 16 MHz. A biased Faraday cup sampled the bunched beam at the position where maximum bunching was nominally expected, about 2.5 meters from the buncher. Part of the drift region, about 1.8 meters, was occupied by a series of Gabor lenses. In addition to enhancing beam transport by transverse focussing, the background cloud of electrons in the lenses provided an extra degree of neutralization. With no lens, the best bunch factor was at least 20. Bunch factor is defined here as the ratio of the distance between bunches to the FWHM bunch length. With the lens, it was hoped that the increased plasma frequency would decrease the neutralization time and cause an increase in the bunch factor. In fact, with the lens, the instantaneous current increased about three times, but the bunch factor dropped to about 10. Even with the lens, the FWHM of the bunches at the position of maximum bunching was still comparable to or less than the oscillation period of the surrounding electron plasma. Thus, the electron density in the lens must increase before neutralization could be effective in this case, or bunching should be done at a lower frequency

Machine Protection with a 700 MJ Beam

Science.gov (United States)

Baer, T.; Schmidt, R.; Wenninger, J.; Wollmann, D.; Zerlauth, M.

After the high luminosity upgrade of the LHC, the stored energy per proton beam will increase by a factor of two as compared to the nominal LHC. Therefore, many damage studies need to be revisited to ensure a safe machine operation with the new beam parameters. Furthermore, new accelerator equipment like crab cavities might cause new failure modes, which are not sufficiently covered by the current machine protection system of the LHC. These failure modes have to be carefully studied and mitigated by new protection systems. Finally the ambitious goals for integrated luminosity delivered to the experiments during the era of HL-LHC require an increase of the machine availability without jeopardizing equipment protection.

Prototype system for phase advance measurements of LHC small beam oscillations

CERN Document Server

Olexa, J; Brezovic, Z; Gasior, M

2013-01-01

Magnet lattice parameters of the Large Hadron Collider (LHC) are measured by exciting beam transverse oscillations that allow measuring their phase advance using the beam position measurement (BPM) system. However, the BPM system requires millimetre oscillation amplitudes, with which nominal high intensity beams would cause large particle loss, dangerous for the LHC superconducting magnets. Therefore, such measurements cannot be done often, as they require special low intensity beams with important set-up time. After its first long shut-down the LHC will be equipped with new collimators with embedded BPMs, for which a new front-end electronics has been developed. Its main processing channels based on compensated diode detectors are designed for beam orbit measurement with sub-micrometre resolution. It is planned to extend this system by adding dedicated channels optimised for phase advance measurement, allowing continuous LHC optics measurement with much smaller beam excitation. This subsystem will be based o...

E-line: A new crystal collimator beam line for source size measurements at CHESS

International Nuclear Information System (INIS)

White, Jeffrey A.; Revesz, Peter; Finkelstein, Ken

2007-01-01

A new X-ray beam line has been constructed at cornell high energy synchrotron source (CHESS) to measure the vertical and horizontal source size of the positron particle beam. The cornell laboratory of elementary particle physics (LEPP) operates the storage ring (CESR) for X-ray generation for the CHESS user community by circulating electrons and their antimatter counterpart positrons in counter-rotating beams. As the laboratory reduces the emittances of particle beams to increase X-ray brilliance, there has been an increasing need for diagnostic tools to measure and monitor source size. A beam line front end that accesses the positron synchrotron light has been fitted with an experimental chamber and apparatus of compact design capable of horizontal and vertical source size measurement using the 'crystal collimator' technique, and an additional setup for vertical beam position monitoring using a luminescence-based X-ray video beam position monitoring system. The crystal collimators each consist of two Si(2 2 0) crystals in a dispersive (+,+) arrangement that diffract X-rays to a fluorescent material coated on a view port observed with a CCD camera. Measurements of the positron vertical beam size using the crystal collimation method at E-line are compared with measurements of visible synchrotron light at a remotely located dedicated port on the storage ring

Attempts to isolate a horizontal high diameter (300 mm nominal diameter) pipeline with an ice plug at minimum water flow and without water flow

International Nuclear Information System (INIS)

Corbescu, B.; Gyongyosi, T.; Puiu, D.; Panaitescu, V. N.

2016-01-01

The ice plug isolation technique used for high diameter horizontal pipes is used for repair and maintenance activities on hydraulic installations that use liquid working agents. These techniques do not require shutting down the entire plant. The ice plug development inside the pipe requires using custom specialized equipment for each individual application. This paper briefly describes the experimental technological facilities used for conducting the experiments and highlights the important aspects in an experiment conducted on a horizontal NPS 12 testing section running demineralized water followed by the result analysis and conclusions. The paper is dedicated to specialists working in research and technological engineering. (authors)

Dilution kicker for the SPS beam dump

CERN Multimedia

1974-01-01

In order to reduce thermal stress on the SPS dump material, the fast-ejected beam was swept horizontally across the dump. This was done with the "dilution kicker" MKDH, still in use at the time of writing. The person on the left is Manfred Mayer. See also 7404072X.

Candidate nomination, intra-party democracy, and election violence in Africa

DEFF Research Database (Denmark)

Seeberg, Merete Bech; Wahman, Michael; Skaaning, Svend-Erik

2018-01-01

. When local-level or national-level competition between parties is low, as in much of Africa, electoral politics become a matter of intra-party rather than inter-party competition. Nominations are a part of the electoral process often left to the discretion of poorly institutionalized parties, free......This article introduces a special issue on candidate nomination, intra-party democracy, and election violence in Africa. Although a burgeoning literature on African democratization has focused on the topic of electoral violence, little attention has been given to violence during party nominations...... of the involvement of electoral management bodies and external monitors, and violence often results. Rather than developing an elaborate theoretical framework on the causes of nomination violence, our ambition in this introduction is to introduce the concept of nomination violence and situate it in the literatures...

Ion-optical studies for a range adaptation method in ion beam therapy using a static wedge degrader combined with magnetic beam deflection

International Nuclear Information System (INIS)

Chaudhri, Naved; Saito, Nami; Bert, Christoph; Franczak, Bernhard; Steidl, Peter; Durante, Marco; Schardt, Dieter; Rietzel, Eike

2010-01-01

Fast radiological range adaptation of the ion beam is essential when target motion is mitigated by beam tracking using scanned ion beams for dose delivery. Electromagnetically controlled deflection of a well-focused ion beam on a small static wedge degrader positioned between two dipole magnets, inside the beam delivery system, has been considered as a fast range adaptation method. The principle of the range adaptation method was tested in experiments and Monte Carlo simulations for the therapy beam line at the GSI Helmholtz Centre for Heavy Ions Research. Based on the simulations, ion optical settings of beam deflection and realignment of the adapted beam were experimentally applied to the beam line, and additional tuning was manually performed. Different degrader shapes were employed for the energy adaptation. Measured and simulated beam profiles, i.e. lateral distribution and range in water at isocentre, were analysed and compared with the therapy beam values for beam scanning. Deflected beam positions of up to ±28 mm on degrader were performed which resulted in a range adaptation of up to ±15 mm water equivalence (WE). The maximum deviation between the measured adapted range from the nominal range adaptation was below 0.4 mm WE. In experiments, the width of the adapted beam at the isocentre was adjustable between 5 and 11 mm full width at half maximum. The results demonstrate the feasibility/proof of the proposed range adaptation method for beam tracking from the beam quality point of view.

Peculiarities of Grammatical Properties in Nominal Word Combinations

Directory of Open Access Journals (Sweden)

Irina B. Klienkova

2014-01-01

Full Text Available The article examines some peculiarities if grammatical properties of nominal word combinations based on the study of German-speaking Swiss press. The accumulated experience of linguists is analyzed and certain factors influencing the choice of syntactic relations in nominal word combinations with quantitative meaning are researched. It has been established that the choice of syntactic relations in such word combinations is determined by functional style, semantics and grammatical features of nouns - first or second components in a word combination. The aforementioned factors influencing the choice of syntactic relations in quantitative nominal word combinations are studied on the material of Germanspeaking Swiss press. The research revealed a number of peculiarities. First of all, German-speaking Swiss press uses such syntactic relation as genitive subordination quite often, not only on "special occasion" and unlike its use in Germany does not produce a magniloquent, pompous impression. Secondly, it has been established that the choice of syntactic relations in word combinations of the above-mentioned type of word combinations greatly depends on the semantic meaning of the noun - the first component of the word combination - and does not always coincide with the grammatical properties in nominal combinations in Germany. Thirdly, a clear dependence of syntactic relations choice is observed. Moreover, the article highlights the importance of grammatical features of the second component. These are such features as gender, number, case accompanied by noun declension. All the afore-mentioned features help to define the type of syntactic relations, which nominal quantitative word combinations may be connected by. The results of the comparisons of grammatical properties of quantitative nominal word combinations in German and Swiss press are demonstrated in a table below.

Nominal completion for rewrite systems with binders

OpenAIRE

Fernández, Maribel; Rubio Gimeno, Alberto

2012-01-01

We design a completion procedure for nominal rewriting systems, based on a generalisation of the recursive path ordering to take into account alpha equivalence. Nominal rewriting generalises first-order rewriting by providing support for the specification of binding operators. Completion of rewriting systems with binders is a notably difficult problem; the completion procedure presented in this paper is the first to deal with binders in rewrite rules. Peer Reviewed

Emittance measuring unit for 100% duty factor linac injector beams

Energy Technology Data Exchange (ETDEWEB)

Shubaly, M R; Pachner, J Jr; Ormrod, J H; Ungrin, J; Schriber, S O [ed.

1976-11-01

A description is given of a system to measure the emittance of a 750 keV 100 mA dc proton beam suitable for injection into a 100% duty factor linear accelerator. A relatively slowly pulsed 45/sup 0/ magnet switches the beam to a beam dump inside the emittance measuring unit for approx. 10 s. A fast pulsed 5/sup 0/ magnet then deflects the beam to a multiple aperture ''pepper-pot'' plate for 300 ..mu..s. Beamlets passing through the plate travel 520 mm and produce a pattern on a scintillator screen. A photograph of the pattern is analyzed to determine beam emittance. Preliminary results on low current beams show a gross increase in the emittance in the horizontal plane.

Specialists' meeting on thermodynamics of FBR fuel subassemblies under nominal and non-nominal operating conditions. Summary report

Energy Technology Data Exchange (ETDEWEB)

1979-01-01

The purpose of the meeting was to provide a forum for exchange of information on thermo- and fluiddynamic investigations of LMFBR-subassembly. Special emphasis was placed on nominal and non-nominal conditions. The technical part of the meeting was divided into four sessions, as follows: status of the thermo- and fluiddynamic activities; physical and mathematical modelling of single phase; rod bundle thermohydraulics; experimental investigations; and future R and D. Separate abstracts are included for each of the papers.

Evaluation of the NEG Coating Saturation Level after 3 Years of LHC Beam Operation

CERN Document Server

Bregliozzi, G; Jimenez, J M; Lanza, G; Porcelli, T

2013-01-01

The room temperature vacuum system of the Large Hadron Collider (LHC) at CERN has been designed to ensure vacuum stability and beam lifetime of 100 h with nominal current of 0.56 A per beam at 7 TeV of energy. The requirements for the interaction regions are moreover driven to minimize the background noise of the experiments, to keep the equivalent hydrogen gas density below 1013 molecules of H2 per m3. \

25 CFR 90.30 - Nominating conventions and petitions.

Science.gov (United States)

2010-04-01

...; also, names of any independent candidates nominated by petition of not less than 25 qualified voters... number of qualified voters in attendance, together with the names of candidates nominated for the various... names may be placed on the official ballot. No person shall be considered a candidate for tribal office...

A variable partially polarizing beam splitter

Science.gov (United States)

Flórez, Jefferson; Carlson, Nathan J.; Nacke, Codey H.; Giner, Lambert; Lundeen, Jeff S.

2018-02-01

We present designs for variably polarizing beam splitters. These are beam splitters allowing the complete and independent control of the horizontal and vertical polarization splitting ratios. They have quantum optics and quantum information applications, such as quantum logic gates for quantum computing and non-local measurements for quantum state estimation. At the heart of each design is an interferometer. We experimentally demonstrate one particular implementation, a displaced Sagnac interferometer configuration, that provides an inherent instability to air currents and vibrations. Furthermore, this design does not require any custom-made optics but only common components which can be easily found in an optics laboratory.

Bending Moment Decrease of Reinforced Concrete Beam Supported by Additional CFRP

Directory of Open Access Journals (Sweden)

Mykolas Daugevičius

2011-04-01

Full Text Available The calculation method of reinforced concrete beam with additional CFRP composite is proposed in this article. This method estimates tangential angular concrete deformations in tensioned beam layers between steel and bonded carbon fiber reinforced polymer. The horizontal slip of CFRP composite reduce beam bending moment capacity. An additional coefficient to reduce CFRP resultant force is necessary for better precision of bending moment capacity. Also, various calculation methods of bending moment capacity are considered. Article in Lithuanian

Beam-transport study of an isocentric rotating ion gantry with minimum number of quadrupoles

International Nuclear Information System (INIS)

Pavlovic, Marius; Griesmayer, Erich; Seemann, Rolf

2005-01-01

A beam-transport study of an isocentric gantry for ion therapy is presented. The gantry is designed with the number of quadrupoles down to the theoretical minimum, which is the feature published for the first time in this paper. This feature has been achieved without compromising the ion-optical functions of the beam-transport system that is capable of handling non-symmetric beams (beams with different emittances in vertical and horizontal plane), pencil-beam scanning, double-achromatic optics and beam-size control. Ion-optical properties of the beam-transport system are described, discussed and illustrated by computer simulations performed by the TRANSPORT-code

SPS transverse beam scraping and LHC injection losses

CERN Document Server

Drosdal, L; Bartmann, W; Bracco, C; Cornelis, K; Goddard, B; Meddahi, M; Veyrunes, E

2012-01-01

Machine protection sets strict requirements for the quality of the injected beam, in particular in the transverse plane. Losses at aperture restrictions and protection elements have to be kept at a minimum. Particles in the beam tails are lost at the tight transfer line collimators and can trigger the LHC beam abort system. These particles have to be removed by scrapers in the vertical and horizontal plane in the SPS. Scraping has become vital for high intensity LHC operation. This paper shows the dependence of injection quality on the SPS scraping and discusses an improved scraper setting up strategy for better reproducibility with the current scraper system.

Influence of X-ray beam angulations on the detection of horizontal root fractures

Directory of Open Access Journals (Sweden)

Josue Martos

2015-01-01

Full Text Available Aims: The aim of this study was to evaluate the variation of vertical angle for detection of fractures. Materials and Methods: Twenty-five (25 single-rooted premolar teeth were divided into two groups, fractured teeth (n = 15 and non-fractured teeth (n = 10. Artificially fractured teeth were classified according to location, number of fragments, and direction of fracture line: Horizontal, oblique, or complex. The tooth fragments were juxtaposed with cyanoacrylate, and the specimens (fractured and non-fractured were placed individually in the dental alveolus of a human jaw with the aid of silicone rubber impression material and submitted to eight periapical radiographs in a digital sensor with a vertical range of 10 degrees (−40, −30, −20, −10, 0, +10, +20, +30. Three examiners evaluated the characteristics of the fractures and their correlation with the radiographic diagnosis (perceived or not by varying the vertical angle. Statistical Analysis: Descriptive analysis was performed through the analytical comparison and Kappa test inter-examiner. Results: Among the three examiners, inter-examiner Kappa value was 0.536. The radiographic identification of root fracture in the 15 prepared samples was 60% (nine at angle 0, and at the angles of +10, −10, and −20, it was less than 50%. Conclusions: Multiple radiographs with variations of vertical angle are fundamental to facilitate the diagnosis of horizontal root fractures in premolars.

Heavy crude production from shallow formations: long horizontal wells versus horizontal fractures

Energy Technology Data Exchange (ETDEWEB)

Valko, P.; Economides, M. J. [Texas A and M Univ., TX (United States)

1998-12-31

The feasibility of producing heavy oil from shallow formations using either horizontal wells or short horizontal wells fractured horizontally is demonstrated. The problem of optimum proppant placement is solved in two steps. In step one, the finite productivity performance is considered in general terms showing that the performance is a function of two dimensionless parameters. Following derivation of optimum conditions, the solution is applied to the horizontal fracture consideration. The limiting factor is that to create an effective finite conductivity fracture, the dimensionless fracture conductivity must be on the order of unity, a fracture that is difficult to realize in higher permeability formations. The best candidates for the suggested configuration are shallow or moderate formations, or formations otherwise proven to accept horizontal fractures, and formations with low permeability/viscosity ratio. 7 refs., 2 tabs., 10 figs., 2 appendices.

7 CFR 25.502 - Nominations by State-chartered economic development corporations.

Science.gov (United States)

2010-01-01

... 7 Agriculture 1 2010-01-01 2010-01-01 false Nominations by State-chartered economic development... AND ENTERPRISE COMMUNITIES Special Rules § 25.502 Nominations by State-chartered economic development corporations. Any rural area nominated by an economic development corporation chartered by a State and...

Beam diffusion measurements using collimator scans in the LHC

CERN Document Server

Valentino, Gianluca; Bruce, Roderik; Burkart, Florian; Previtali, Valentina; Redaelli, Stefano; Salvachua, Belen; Stancari, Giuliov; Valishev, Alexander

2013-01-01

The time evolution of beam losses during a collimator scan provides information on halo diffusion and population. This is an essential input for machine performance characterization and for the design of collimation systems. Beam halo measurements in the CERN Large Hadron Collider were conducted through collimator scrapings in a dedicated beam study for the first time at 4 TeV. Four scans were performed with two collimators, in the vertical plane for beam 1 and horizontally for beam 2, before and after bringing the beams into collisions. Inward and outward steps were performed. A diffusion model was used to interpret the observed loss rate evolution in response to the collimator steps. With this technique, diffusion coefficients were estimated as a function of betatron oscillation amplitude from approximately 3 to 7 standard deviations of the transverse beam distribution. A comparison of halo diffusion and core emittance growth rates is also presented.

Beam equipment electromagnetic interaction in accelerators: simulation and experimental benchmarking

CERN Document Server

Passarelli, Andrea; Vaccaro, Vittorio Giorgio; Massa, Rita; Masullo, Maria Rosaria

One of the most significant technological problems to achieve the nominal performances in the Large Hadron Collider (LHC) concerns the system of collimation of particle beams. The use of collimators crystals, exploiting the channeling effect on extracted beam, has been experimentally demonstrated. The first part of this thesis is about the optimization of UA9 goniometer at CERN, this device used for beam collimation will replace a part of the vacuum chamber. The optimization process, however, requires the calculation of the coupling impedance between the circulating beam and this structure in order to define the threshold of admissible intensity to do not trigger instability processes. Simulations have been performed with electromagnetic codes to evaluate the coupling impedance and to assess the beam-structure interaction. The results clearly showed that the most concerned resonance frequencies are due solely to the open cavity to the compartment of the motors and position sensors considering the crystal in o...

Experimental determination of beam quality conversion factors kQ in clinical photon beams using ferrous sulphate (Fricke) dosimetry

International Nuclear Information System (INIS)

Palm, A.; Mattsson, Olof

2002-01-01

The implementation of protocols based on absorbed dose to water standards requires beam quality conversion factors, k Q . Calculated values of k Q are available for ionization chambers used for reference dosimetry. Ideally, k Q should be experimentally determined at the same beam qualities as that of the user. In this work we measure k Q factors in clinical photon beams and compare them with calculated and measured values. Beam quality conversion factors are determined for clinical photon beams of nominal energies 4 MV, 6 MV, 15 MV, and 25 MV, for commonly used cylindrical ionization chambers. Twelve chambers of eight different types are used. For three of them, no experimental data have previously been available. The experimental procedure is based on measurements with ionization chambers and Fricke dosimetry in the reference beam ( 60 Co γ radiation) and in clinical linear accelerator beams. The k Q values determined in this work generally agree within 0.5% with previously reported experimental values both when %dd(10) x and TPR 20,10 are used for beam quality specification. The agreement with calculated data is generally within 0.5%, except for the 15 MV beam. For this beam the measured values are usually between 0.5% and 1% lower than the data taken from the TG-51 protocol or the TRS-398 code of practice. For three NE2571 chambers and three NE2581 chambers, the maximum observed deviation of individual k Q values is 0.2% and 0.4%, respectively

15 years of The Hungarian integral type test facility: horizontal SG related PMK-2 experiments

International Nuclear Information System (INIS)

Perneczky, L.; Ezsoel, G.; Guba, A.; Szabados, L.

2001-01-01

The PMK-2 experimental facility at the KFKI-AEKI, Budapest, is a full pressure, scaled down model of the primary and partly the secondary circuit of the Paks Nuclear Power Plant. This NPP is equipped with four VVER-440/213-type reactors. Such plants are slightly different from PWRs of usual design and have a number of special features as 6-loop primary circuit, horizontal steam generators, loop seal in hot and cold legs, setpoint pressure of passive safety injection tanks (SIT) higher than secondary pressure, etc. The PMK-2 was primarily designed for investigating operational and off-normal transient processes, as well as small-break loss of coolant accidents of Paks NPP. The volume and power scaling ratios are 1:2070. Due to the importance of gravitational forces in both single- and two-phase flow the elevation ratio is 1:1 except for the lower plenum and pressuriser. The six loops of the plant are modelled by a single active loop. Transients can be started from nominal operating conditions. The pressuriser (PRZ) is connected to the lower part of the hot leg as in the reference system. The core model consists of 19 electrically heated rods. The main circulating pump of the PMK-2 serves to produce the nominal operating conditions and to simulate the flow coast-down following pump trip. The horizontal design of the VVER-440 steam generator is modelled by horizontal heat transfer tubes between hot and cold vertical collectors in the primary side. The emergency core cooling systems including the SITs. High and low pressure injection systems of the Paks NPP are also modelled. The first design of the PMK-NVH facility only modelled the primary circuit of plant. This version was used until 1990. The PMK-2 facility is an upgraded version (first of all by addition of a controlled secondary heat removal system) extending the capability of the test loop to modelling transient processes evoked by initiating events in the secondary circuit or including accident sequences in

CERN Vacuum-System Activities during the Long Shutdown 1: The LHC Beam Vacuum

CERN Document Server

Baglin, V; Chiggiato, P; Jimenez, JM; Lanza, G

2014-01-01

After the Long Shutdown 1 (LS1) and the consolidation of the magnet bus bars, the CERN Large Hadron Collider (LHC) will operate with nominal beam parameters. Larger beam energy, beam intensities and luminosity are expected. Despite the very good performance of the beam vacuum system during the 2010-12 physics run (Run 1), some particular areas require attention for repair, consolidation and upgrade. Among the main activities, a large campaign aiming at the repair of the RF bridges of some vacuum modules is conducted. Moreover, consolidation of the cryogenic beam vacuum systems with burst disk for safety reasons is implemented. In addition, NEG cartridges, NEG coated inserts and new instruments for the vacuum system upgrade are installed. Besides these activities, repair, consolidation and upgrades of other beam equipment such as collimators, kickers and beam instrumentations are carried out. In this paper, the motivation and the description for such activities, together with the expected beam vacuum performa...

Windowless Electron Beam Experimental Irradiation WEBExplr

International Nuclear Information System (INIS)

Heyse, J.

2009-01-01

The design of the MYRRHA/XT-ADS, the European eXperimental Accelerator Driven System for the demonstration of Transmutation, includes a high power windowless spallation target operating with liquid LBE (Lead-Bismuth Eutectic) that will be irradiated with a 600 MeV proton beam at currents of up to 2.5 mA. When considering such a high power windowless target design, a number of questions need to be addressed, such as the stability of the free surface flow and its ability to remove the power deposited by the proton beam by forced convection, the compatibility of a large hot LBE reservoir with the beam line vacuum and the outgassing of the LBE in the spallation target circuit. These issues have been studied during previous experiments supported by numerical simulations. Another crucial point in the development of the spallation target is the demonstration of the safe and stable operation of the free LBE surface during irradiation with a high power proton beam. As a first step in this program, the WEBExpIr (Windowless target Electron Beam Experimental Irradiation) experiment was set up. The purpose of the WEBExpIr experiment was to investigate the influence of LBE surface heating caused by a charged particle beam in a situation representative of the MYRRHA/XT-ADS. More in particular, we wanted to assess possible free surface distortion or shockwave effects in nominal conditions and during sudden beam on/off transient situations, as well as possible enhanced evaporation

Electron-beam deposition of vanadium dioxide thin films

Energy Technology Data Exchange (ETDEWEB)

Marvel, R.E.; Appavoo, K. [Vanderbilt University, Interdisciplinary Materials Science Program, Nashville, TN (United States); Choi, B.K. [Vanderbilt University, Department of Electrical Engineering and Computer Science, Nashville, TN (United States); Nag, J. [Vanderbilt University, Department of Physics and Astronomy, Nashville, TN (United States); Haglund, R.F. [Vanderbilt University, Interdisciplinary Materials Science Program, Nashville, TN (United States); Vanderbilt University, Institute for Nanoscale Science and Engineering, Nashville, TN (United States); Vanderbilt University, Department of Physics and Astronomy, Nashville, TN (United States)

2013-06-15

Developing a reliable and efficient fabrication method for phase-transition thin-film technology is critical for electronic and photonic applications. We demonstrate a novel method for fabricating polycrystalline, switchable vanadium dioxide thin films on glass and silicon substrates and show that the optical switching contrast is not strongly affected by post-processing annealing times. The method relies on electron-beam evaporation of a nominally stoichiometric powder, followed by fast annealing. As a result of the short annealing procedure we demonstrate that films deposited on silicon substrates appear to be smoother, in comparison to pulsed laser deposition and sputtering. However, optical performance of e-beam evaporated film on silicon is affected by annealing time, in contrast to glass. (orig.)

Interaction of the CERN Large Hadron Collider (LHC) Beam with Carbon Collimators

CERN Document Server

Schmidt, R; Hoffmann, Dieter H H; Kadi, Y; Shutov, A; Piriz, AR

2006-01-01

The LHC will operate at an energy of 7 TeV with a luminosity of 1034cm-2s-1. This requires two beams, each with 2808 bunches. The energy stored in each beam of 362 MJ. In a previous paper the mechanisms causing equipment damage in case of a failure of the machine protection system was discussed, assuming that the entire beam is deflected into a copper target [1, 2]. Another failure scenario is the deflection of beam into carbon material. Carbon collimators and beam absorbers are installed in many locations around the LHC to diffuse or absorb beam losses. Since the collimator jaws are close to the beam, it is very likely that they are hit first when the beam is accidentally deflected. Here we present the results of two-dimensional hydrodynamic simulations of the heating of a solid carbon cylinder irradiated by the LHC beam with nominal parameters, carried out using the BIG-2 computer code [3] while the energy loss of the 7 TeV protons in carbon is calculated using the well known FLUKA code [4]. Our calculation...

E-line: A new crystal collimator beam line for source size measurements at CHESS

Energy Technology Data Exchange (ETDEWEB)

White, Jeffrey A. [CHESS, Cornell High Energy Synchrotron Source, Cornell University, Ithaca, NY 14850-8001 (United States)], E-mail: jaw7@cornell.edu; Revesz, Peter; Finkelstein, Ken [CHESS, Cornell High Energy Synchrotron Source, Cornell University, Ithaca, NY 14850-8001 (United States)

2007-11-11

A new X-ray beam line has been constructed at cornell high energy synchrotron source (CHESS) to measure the vertical and horizontal source size of the positron particle beam. The cornell laboratory of elementary particle physics (LEPP) operates the storage ring (CESR) for X-ray generation for the CHESS user community by circulating electrons and their antimatter counterpart positrons in counter-rotating beams. As the laboratory reduces the emittances of particle beams to increase X-ray brilliance, there has been an increasing need for diagnostic tools to measure and monitor source size. A beam line front end that accesses the positron synchrotron light has been fitted with an experimental chamber and apparatus of compact design capable of horizontal and vertical source size measurement using the 'crystal collimator' technique, and an additional setup for vertical beam position monitoring using a luminescence-based X-ray video beam position monitoring system. The crystal collimators each consist of two Si(2 2 0) crystals in a dispersive (+,+) arrangement that diffract X-rays to a fluorescent material coated on a view port observed with a CCD camera. Measurements of the positron vertical beam size using the crystal collimation method at E-line are compared with measurements of visible synchrotron light at a remotely located dedicated port on the storage ring.

78 FR 90 - National Medal of Technology and Innovation Call for 2013 Nominations

Science.gov (United States)

2013-01-02

... successful products and services. Eligibility and Nomination Criteria: Nomination Guidelines and nomination...] National Medal of Technology and Innovation Call for 2013 Nominations AGENCY: United States Patent and... Medal of Technology and Innovation (NMTI). Since establishment by Congress in the Stevenson-Wydler...

Experimental Investigations of Cochannel Interference Reduction Effect at High Elevation Base Station Using Beam Tilt and Orthogonal Polarization

Directory of Open Access Journals (Sweden)

Shuta Uwano

2014-01-01

Full Text Available This paper addresses the problem of cochannel interference (CCI generated in a mixed cell architecture in microcellular systems. In this type of microcellular systems in which both microcells and macrocells coexist in the same geographical urban area, the base station antennas mounted on the rooftops of buildings to cover wide circular radio zones suffer severe CCI from the surrounding low base stations. A dielectric-loaded slotted-cylinder antenna (DSCA is applied to horizontally polarized omnidirectional array antennas in a height-diversity configuration with the high gain of 8 dBi, which is comparable to that of a collinear antenna, to reduce the CCI. The measurements conducted in a suburban area clarify the reduction in the CCI for three techniques. The beam-tilt technique reduces the CCI level by approximately 10 dB for both collinear antennas and the DSCA array antennas. The use of horizontal polarization reduces the CCI level by approximately 13 dB for the DSCA array antennas with and without beam tilt. The combination of the beam tilt and horizontal polarization or the DSCA array antennas with beam tilt significantly reduces the CCI level by approximately 23 dB.

Implementation and validation of the linear collider final focus prototype: ATF2 at KEK (Japan); Implementation et validation de la focalisation finale du collisionneur lineaire: ATF2 at KEK (Japan)

Energy Technology Data Exchange (ETDEWEB)

Renier, Y.

2010-06-15

The two linear collider projects (ILC and CLIC) require beam delivery systems with the same local chromaticity correction scheme in the final focus. ATF2 at KEK (Japan), an implementation of this scheme scaled down in energy, uses the beam extracted from ATF, which is one of the most successful damping rings in the world. The ATF2 goals are to prove the feasibility and the stability of the linear collider final focus system and to define and test the experimental correction procedures. The nominal beam sizes at the interaction point are 3 {mu}m horizontally and 37 nm vertically. The work in this thesis was started before the commissioning and covered its first year at KEK. At the beginning, we observed that the stripline BPMs were not working properly so we investigated their behavior in detail. The problem was characterized and later solved in 2010 by upgrading the electronics. We then developed an efficient procedure to check the modeling of the beam line, comparing measurements of transfer matrices to model predictions calculated on line. After obtaining a good agreement, we were able to successfully test the trajectory correction algorithm which had been developed, reducing the difference between BPM measurements and the target values down to 0.5 mm horizontally and 0.2 mm vertically. We also successfully developed an algorithm to reconstruct pulse to pulse beam trajectory fluctuations with sub-micron precision. This reconstruction also gave a precise determination of the energy fluctuation, allowing a global fit of the dispersion function along the beam line with a precision of a few mm. A simple and robust IP beam size tuning method using sextupoles displacements was also studied in simulation, whose performance indicates that, given some assumptions on the error level of the beam, convergence within 20% of the nominal beam size should be possible in 8 hours with a 80% probability. (author)

Implementation and validation of the linear collider final focus prototype: ATF2 at KEK (Japan)

International Nuclear Information System (INIS)

Renier, Y.

2010-06-01

The two linear collider projects (ILC and CLIC) require beam delivery systems with the same local chromaticity correction scheme in the final focus. ATF2 at KEK (Japan), an implementation of this scheme scaled down in energy, uses the beam extracted from ATF, which is one of the most successful damping rings in the world. The ATF2 goals are to prove the feasibility and the stability of the linear collider final focus system and to define and test the experimental correction procedures. The nominal beam sizes at the interaction point are 3 μm horizontally and 37 nm vertically. The work in this thesis was started before the commissioning and covered its first year at KEK. At the beginning, we observed that the stripline BPMs were not working properly so we investigated their behavior in detail. The problem was characterized and later solved in 2010 by upgrading the electronics. We then developed an efficient procedure to check the modeling of the beam line, comparing measurements of transfer matrices to model predictions calculated on line. After obtaining a good agreement, we were able to successfully test the trajectory correction algorithm which had been developed, reducing the difference between BPM measurements and the target values down to 0.5 mm horizontally and 0.2 mm vertically. We also successfully developed an algorithm to reconstruct pulse to pulse beam trajectory fluctuations with sub-micron precision. This reconstruction also gave a precise determination of the energy fluctuation, allowing a global fit of the dispersion function along the beam line with a precision of a few mm. A simple and robust IP beam size tuning method using sextupoles displacements was also studied in simulation, whose performance indicates that, given some assumptions on the error level of the beam, convergence within 20% of the nominal beam size should be possible in 8 hours with a 80% probability. (author)

Tense and Mood in Basque Nominalizations

Directory of Open Access Journals (Sweden)

Jon Ortiz de Urbina

2005-06-01

Full Text Available This article examines the role of tense and mood factors in the selection of complement clauses in Basque, arguing against apparent cases of free variation, discussed here with respect to choice of complement types. In particular, the article concentrates on the ability of some verb classes to take complements in the nominalized form. As with Spanish infinitives, the availability of nominalized complements correlates with the class membership of the main predicate into one of the subjunctive-taking groups. Apparent counterexamples, i.e., predicates which can take both a nominalized/subjunctive complement and an indicative one, will be shown to stem from differences in modality and tense. Variation is considered from a cross-linguistic perspective, and the discussion of the Basque examples is linked to 'double selection' phenomena in Spanish and Romance complements. Particular attention is paid to prospective complements, and a semantic approach is offered to explain why double selection phenomena emerge in this particular case. As expected, while the morphology of Basque and Spanish complement types is strikingly different, the semantic factors intervening in the choice and distribution of complement types will be shown not display the same degree of variation.

500 MHz narrowband beam position monitor electronics for electron synchrotrons

International Nuclear Information System (INIS)

Mohos, I.; Dietrich, J.

1998-01-01

Narrowband beam position monitor electronics were developed in the Forschungszentrum Juelich-IKP for the orbit measurement equipment used at ELSA Bonn. The equipment uses 32 monitor chambers, each with four capacitive button electrodes. The monitor electronics, consisting of an rf signal processing module (BPM-RF) and a data acquisition and control module (BPM-DAQ), sequentially process and measure the monitor signals and deliver calculated horizontal and vertical beam position data via a serial network

500 MHz narrowband beam position monitor electronics for electron synchrotrons

Science.gov (United States)

Mohos, I.; Dietrich, J.

1998-12-01

Narrowband beam position monitor electronics were developed in the Forschungszentrum Jülich-IKP for the orbit measurement equipment used at ELSA Bonn. The equipment uses 32 monitor chambers, each with four capacitive button electrodes. The monitor electronics, consisting of an rf signal processing module (BPM-RF) and a data acquisition and control module (BPM-DAQ), sequentially process and measure the monitor signals and deliver calculated horizontal and vertical beam position data via a serial network.

Online beam energy measurement of Beijing electron positron collider II linear accelerator

Science.gov (United States)

Wang, S.; Iqbal, M.; Liu, R.; Chi, Y.

2016-02-01

This paper describes online beam energy measurement of Beijing Electron Positron Collider upgraded version II linear accelerator (linac) adequately. It presents the calculation formula, gives the error analysis in detail, discusses the realization in practice, and makes some verification. The method mentioned here measures the beam energy by acquiring the horizontal beam position with three beam position monitors (BPMs), which eliminates the effect of orbit fluctuation, and is much better than the one using the single BPM. The error analysis indicates that this online measurement has further potential usage such as a part of beam energy feedback system. The reliability of this method is also discussed and demonstrated in this paper.

Crystal Collimation with Lead Ion Beams at Injection Energy in the LHC

CERN Document Server

Rossi, Roberto; Andreassen, Arvid; Butcher, Mark; Dionisio Barreto, Cristovao Andre; Masi, Alessandro; Mirarchi, Daniele; Montesano, Simone; Lamas Garcia, Inigo; Redaelli, Stefano; Scandale, Walter; Serrano Galvez, Pablo; Rijllart, Adriaan; Valentino, Gianluca; Galluccio, Francesca; CERN. Geneva. ATS Department

2015-01-01

During this MD, performed on December 2nd 2015, bent silicon crystals were tested with ion beams for a possible usage of crystal-assisted collimation. Tests were performed at injection energy, using both horizontal and vertical crystals. Ion channeling was observed for the first time with LHC beams at the record energy of 450 GeV and the channeled beams were probed with scans performed with secondary collimators. Measurements of cleaning efficiency of a crystal-based collimation system were also performed.

Horizontal Air-Water Flow Analysis with Wire Mesh Sensor

International Nuclear Information System (INIS)

De Salve, M; Monni, G; Panella, B

2012-01-01

A Wire Mesh Sensor, based on the measurement of the local instantaneous conductivity of the two-phase mixture, has been used to characterize the fluid dynamics of the gas–liquid interface in a horizontal pipe flow. Experiments with a pipe of a nominal diameter of 19.5 mm and total length of 6 m, have been performed with air/water mixtures, at ambient conditions. The flow quality ranges from 0.00016 to 0.22 and the superficial velocities range from 0.1 to 10.5 m/s for air and from 0.02 to 1.7 m/s for water; the flow pattern is stratified, slug/plug and annular. A sensor (WMS200) with an inner diameter of 19.5 mm and a measuring matrix of 16×16 points equally distributed over the cross-section has been chosen for the measurements. From the analysis of the Wire Mesh Sensor digital signals the average and the local void fraction are evaluated and the flow patterns are identified with reference to space, time and flow rate boundary conditions.

Commissioning status of the decelerator test beam line in CTF3

CERN Document Server

Adli, E; Lillestol, R; Olvegaard, M; Syratchev, I; Carrillo, D; Toral, F; Faus-Golfe, A; Garcia-Garrigos, J J; Kubyshin, Y; Montoro, G

2010-01-01

The CLIC Test Facility (CTF3) at CERN was constructed by the CTF3 collaboration to study the feasibility of the concepts for a compact linear collider. The test beam line (TBL) recently added to the CTF3 machine was designed to study the CLIC decelerator beam dynamics and 12 GHz power production. The beam line consists of a FODO lattice with high precision BPM’s and quadrupoles on movers for precise beam alignment. A total of 16 Power Extraction and Transfer Structures (PETS) will be installed in between the quadrupoles to extract 12 GHz power from the drive beam provided by the CTF3 machine. The CTF3 drive beam with a bunch-train length of 140 ns, 12 GHz bunch repetition frequency and an average current over the train of up to 28 A will be injected into the test beam line. Each PETS structure will produce 135 MW of 12 GHz power at nominal current. The beam will have lost more than 50 % of its initial energy of 150 MeV at the end of the beam line and will contain particles with energies between 65 MeV and 1...

Case study to remove radioactive hazardous sludge from long horizontal storage tanks

International Nuclear Information System (INIS)

Hylton, T.D.; Youngblood, E.L.; Cummins, R.L.

1995-01-01

The removal of radioactive hazardous sludge from waste tanks is a significant problem at several US Department of Energy (DOE) sites. The use of submerged jets produced by mixing pumps lowered into the supernatant/sludge interface to produce a homogeneous slurry is being studied at several DOE facilities. The homogeneous slurry can be pumped from the tanks to a treatment facility or alternative storage location. Most of the previous and current studies with this method are for flat-bottom tanks with vertical walls. Because of the difference in geometry, the results of these studies are not directly applicable to long horizontal tanks such as those used at the Oak Ridge National Laboratory. Mobilization and mixing studies were conducted with a surrogate sludge (e.g., kaolin clay) using submerged jets in two sizes of horizontal tanks. The nominal capacities of these tanks were 0.87 m 3 (230 gal) and 95 m 3 (25,000 gal). Mobilization efficiencies and mixing times were determined for single and bidirectional jets in both tanks with the discharge nozzles positioned at two locations in the tanks. Approximately 80% of the surrogate sludge was mobilized in the 95-m 3 tank using a fixed bidirectional jet (inside diameter = 0.035 m) and a jet velocity of 6.4 m/s (21 ft/s)

Beam diffusion measurements using collimator scans in the LHC

Directory of Open Access Journals (Sweden)

Gianluca Valentino

2013-02-01

Full Text Available The time evolution of beam losses during a collimator scan provides information on halo diffusion and population. This is an essential input for machine performance characterization and for the design of collimation systems. Beam halo measurements in the CERN Large Hadron Collider were conducted through collimator scrapings in a dedicated beam study for the first time at 4 TeV. Four scans were performed with two collimators, in the vertical plane for beam 1 and horizontally for beam 2, before and after bringing the beams into collisions. Inward and outward steps were performed. A diffusion model was used to interpret the observed loss rate evolution in response to the collimator steps. With this technique, diffusion coefficients were estimated as a function of betatron oscillation amplitude from approximately 3 to 7 standard deviations of the transverse beam distribution. A comparison of halo diffusion and core emittance growth rates is also presented.

Horizontal wells in subsurface remediation

International Nuclear Information System (INIS)

Losonsky, G.; Beljin, M.S.

1992-01-01

This paper reports on horizontal wells which offer an effective alternative to vertical wells in various environmental remediation technologies. Hydrogeological advantages of horizontal wells over vertical wells include a larger zone of influence, greater screen length, higher specific capacity and lower groundwater screen entrance velocity. Because of these advantages, horizontal wells can reduce treatment time and costs of groundwater recovery (pump-and-treat), in situ groundwater aeration (sparging) and soil gas extraction (vacuum extraction). Horizontal wells are also more effective than vertical wells in landfill leachate collection (under-drains), bioremediation, and horizontal grout injection

Noninteractive beam position and size monitor for heavy ions

International Nuclear Information System (INIS)

Bogaty, J.M.

1979-01-01

The Ion Beam Fusion development program at Argonne National Laboratory requires noninteractive size measurements of a pulsed, 30 mA, Xe +1 particle beam. Pulses of 100 μs duration will be produced by the 1.5 MV preaccelerator; therefore, fast response diagnostics are required. Techniques of utilizing residual gas ionization to profile particle beams have been reported before. This paper discusses the development of vertical and horizontal beam profile monitors that are synchronously clocked to interface with oscilloscopes and computers. Modern integrated circuitry is utilized which boosts performance to a point where pulses as short as 20 μs can be analyzed. A small, simple ionization chamber is shown which provides sixteen channels of position resolution over 12 cm of aperture

SU-D-BRC-01: An Automatic Beam Model Commissioning Method for Monte Carlo Simulations in Pencil-Beam Scanning Proton Therapy

Energy Technology Data Exchange (ETDEWEB)

Qin, N; Shen, C; Tian, Z; Jiang, S; Jia, X [UT Southwestern Medical Ctr, Dallas, TX (United States)

2016-06-15

Purpose: Monte Carlo (MC) simulation is typically regarded as the most accurate dose calculation method for proton therapy. Yet for real clinical cases, the overall accuracy also depends on that of the MC beam model. Commissioning a beam model to faithfully represent a real beam requires finely tuning a set of model parameters, which could be tedious given the large number of pencil beams to commmission. This abstract reports an automatic beam-model commissioning method for pencil-beam scanning proton therapy via an optimization approach. Methods: We modeled a real pencil beam with energy and spatial spread following Gaussian distributions. Mean energy, and energy and spatial spread are model parameters. To commission against a real beam, we first performed MC simulations to calculate dose distributions of a set of ideal (monoenergetic, zero-size) pencil beams. Dose distribution for a real pencil beam is hence linear superposition of doses for those ideal pencil beams with weights in the Gaussian form. We formulated the commissioning task as an optimization problem, such that the calculated central axis depth dose and lateral profiles at several depths match corresponding measurements. An iterative algorithm combining conjugate gradient method and parameter fitting was employed to solve the optimization problem. We validated our method in simulation studies. Results: We calculated dose distributions for three real pencil beams with nominal energies 83, 147 and 199 MeV using realistic beam parameters. These data were regarded as measurements and used for commission. After commissioning, average difference in energy and beam spread between determined values and ground truth were 4.6% and 0.2%. With the commissioned model, we recomputed dose. Mean dose differences from measurements were 0.64%, 0.20% and 0.25%. Conclusion: The developed automatic MC beam-model commissioning method for pencil-beam scanning proton therapy can determine beam model parameters with

Finite element modelling of reinforced large-opening on the web of steel beam considering axial forces

Science.gov (United States)

Sukrawa, Made

2017-11-01

Experimental and analytical researches on the effect of web opening in steel beams have been repeatedly reported in literature because of the advantages gain from the many function of the opening. Most of the research on this area, however, did not consider deformation and stress in the beam due to axial force. In seismic design of steel structure, the axial force in the beam could be significantly high and therefore worth considering. In this study a beam extracted from a braced frame structure was analyzed using finite element models to investigate the effect of combined bending and axial forces on the deformation and stresses in the vicinity of the opening. Large size of square, rectangular, and circular openings of the same depth were reinforced and placed in pair, symmetrical to the concentrated load at mid span of the beam. Four types of reinforcement were used, all around (AA), short horizontal (SH), long horizontal (LH), and doubler plate (DP). The effect of axial load was also investigated using rigid frame model loaded vertically and laterally. Validation of the modelling technique was done prior to the parametric study. It was revealed that the axial force significantly contributes to the stress concentration near the hole. Stiffener of circular shape was effective to improve the stress distribution around the circular opening. For square and rectangular openings, however, the horizontal stiffener, extended beyond the edge of opening, performed better than the other type of stiffeners.

Money illusion and nominal inertia in experimental asset markets

NARCIS (Netherlands)

Noussair, C.N.; Richter, G.; Tyran, J.R.

2012-01-01

We test whether large but purely nominal shocks affect real asset market prices. We subject a laboratory asset market to an exogenous shock, which either inflates or deflates the nominal fundamental value of the asset while holding the real fundamental value constant. After an inflationary shock,

Money Illusion and Nominal Inertia in Experimental Asset Markets

DEFF Research Database (Denmark)

Noussair, Charles N.; Richter, Gregers; Tyran, Jean-Robert

We test whether large but purely nominal shocks affect real asset market prices. We subject a laboratory asset market to an exogenous shock, which either inflates or deflates the nominal fundamental value of the asset, while holding the real fundamental value constant. After an inflationary shock...

7 CFR 1260.143 - Nominations.

Science.gov (United States)

2010-01-01

... Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE BEEF PROMOTION AND RESEARCH Beef Promotion and Research Order Cattlemen's Beef Promotion and Research Board § 1260.143 Nominations. All...

Properties of horizontally oriented ice crystals observed by polarization lidar over summit, Greenland

Directory of Open Access Journals (Sweden)

Neely Ryan R.

2018-01-01

Full Text Available A source of error in microphysical retrievals and model simulations is the assumption that clouds are composed of only randomly oriented ice crystals. This assumption is frequently not true, as evidenced by optical phenomena such as parhelia. Here, observations from the Cloud, Aerosol and Polarization Backscatter Lidar at Summit, Greenland are utilized along with other sensors and beam imaging to examine the properties of horizontally oriented ice crystals and the environment conditions in which they occur.

Characteristics of Sissi beams in the transport lines of Ganil

International Nuclear Information System (INIS)

Nghiem, P.; Payet, J.; Tkatchenko, A.

1994-01-01

This study is the following of the Sissi primary beam characteristics definition. Its aim is to determine the performances in resolution and in transmission of transport lines which guide the secondary beams until the experimentation rooms. The first part concerns the study of the secondary order characteristics with the help of BETA matrix code for the nominal case. The second part is the same study but but of superior orders carried out with the Zgoubi program. The third part consists to search new regulating to minimise the losses of particles due to the effect of non-linearity. (O.L.). 3 refs., 34 figs., 5 tabs

Experimental Study of the Effect of Beam Loading on RF Breakdown Rate in CLIC High-Gradient Accelerating Structures

CERN Document Server

Tecker, F; Kelisani, M; Doebert, S; Grudiev, A; Quirante, J; Riddone, G; Syratchev, I; Wuensch, W; Kononenko, O; Solodko, A; Lebet, S

2013-01-01

RF breakdown is a key issue for the multi-TeV highluminosity e+e- Compact Linear Collider (CLIC). Breakdowns in the high-gradient accelerator structures can deflect the beam and decrease the desired luminosity. The limitations of the accelerating structures due to breakdowns have been studied so far without a beam present in the structure. The presence of the beam modifies the distribution of the electrical and magnetic field distributions, which determine the breakdown rate. Therefore an experiment has been designed for high power testing a CLIC prototype accelerating structure with a beam present in the CLIC Test Facility (CTF3). A special beam line allows extracting a beam with nominal CLIC beam current and duration from the CTF3 linac. The paper describes the beam optics design for this experimental beam line and the commissioning of the experiment with beam.

Present status of neutron beam facilities at the research reactor, HANARO, and its future prospect

Energy Technology Data Exchange (ETDEWEB)

Lee, Chang-Hee; Kang, Young-Hwan; Kuk, Il-Hiun [Korea Atomic Energy Research Institute, Taejon (Korea)

2001-03-01

Korea has been operating its new research reactor, HANARO, since its first criticality in 1995. It is an open-tank-in-pool type reactor using LEU fuel with thermal neutron flux of 2 x 10{sup 14} nominally at the nose in the D{sub 2}O reflector having 7 horizontal beam ports and a provision of vertical hole for cold neutron source installation. KAERI has pursued an extensive instrument development program since 1992 by the support of the nuclear long-term development program of the government and there are now 4 working instruments. A high resolution powder diffractometer and a neutron radiography facility has been operational since late 1997 and 1996, respectively. A four-circle diffractometer has been fully working since mid 1999 and a small angle neutron spectrometer is just under commissioning phase. With the development of linear position sensitive detector with delay-line readout electronics, we have developed a residual stress instrument as an optional machine to the HRPD for last two years. Around early 1998 informal users program started with friendly users and it became a formal users support program by the ministry of science and technology. Short description for peer group formation and users activities is given. (author)

Present status of neutron beam facilities at the research reactor, HANARO, and its future prospect

International Nuclear Information System (INIS)

Lee, Chang-Hee; Kang, Young-Hwan; Kuk, Il-Hiun

2001-01-01

Korea has been operating its new research reactor, HANARO, since its first criticality in 1995. It is an open-tank-in-pool type reactor using LEU fuel with thermal neutron flux of 2 x 10 14 nominally at the nose in the D 2 O reflector having 7 horizontal beam ports and a provision of vertical hole for cold neutron source installation. KAERI has pursued an extensive instrument development program since 1992 by the support of the nuclear long-term development program of the government and there are now 4 working instruments. A high resolution powder diffractometer and a neutron radiography facility has been operational since late 1997 and 1996, respectively. A four-circle diffractometer has been fully working since mid 1999 and a small angle neutron spectrometer is just under commissioning phase. With the development of linear position sensitive detector with delay-line readout electronics, we have developed a residual stress instrument as an optional machine to the HRPD for last two years. Around early 1998 informal users program started with friendly users and it became a formal users support program by the ministry of science and technology. Short description for peer group formation and users activities is given. (author)

Ions for LHC Beam Physics and Engineering Challenges

CERN Document Server

Maury, Stephan; Baggiolini, Vito; Beuret, Andre; Blas, Alfred; Borburgh, Jan; Braun, Hans Heinrich; Carli, Christian; Chanel, Michel; Fowler, Tony; Gilardoni, S S; Gourber-Pace, Marine; Hancock, Steven; Hill, Charles E; Hourican, Michael; Jowett, John M; Kahle, Karsten; Kuchler, Detlef; Mahner, Edgar; Manglunki, Django; Martini, Michel; Paoluzzi, Mauro M; Pasternak, Jaroslaw; Pedersen, Flemming; Raich, Uli; Rossi, Carlo; Royer, Jean Pierre; Schindl, Karlheinz; Scrivens, Richard; Sermeus, Luc; Shaposhnikova, Elena; Tranquille, Gerard; Vretenar, Maurizio; Zickler, Thomas

2005-01-01

The first phase of the heavy ion physics program at the LHC aims to provide lead-lead collisions at energies of 5.5 TeV per colliding nucleon pair and ion-ion luminosity of 1027 cm-2s-1. The transformation of CERN’s ion injector complex (Linac3-LEIR-PS-SPS) presents a number of beam physics and engineering challenges, which are described in this paper. In the LHC itself, there are fundamental performance limitations due to various beam loss mechanisms. To study these without risk of damage there will be an initial period of operation with a reduced number of nominal intensity bunches. While reducing the work required to commission the LHC with ions in 2008, this will still enable early physics discoveries.

7 CFR 1280.202 - Nominations.

Science.gov (United States)

2010-01-01

... 7 Agriculture 10 2010-01-01 2010-01-01 false Nominations. 1280.202 Section 1280.202 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS... INFORMATION ORDER Lamb Promotion, Research, and Information Order Lamb Promotion, Research, and Information...

Visible-light beam size monitors using synchrotron radiation at CESR

Energy Technology Data Exchange (ETDEWEB)

Wang, S.T., E-mail: sw565@cornell.edu [Cornell Laboratory for Accelerator-Based Science and Education, Cornell University, Ithaca, NY 14853 (United States); Rubin, D.L.; Conway, J.; Palmer, M.; Hartill, D. [Cornell Laboratory for Accelerator-Based Science and Education, Cornell University, Ithaca, NY 14853 (United States); Campbell, R.; Holtzapple, R. [Physics Department, California Polytechnic State University, San Luis Obispo, CA 93407 (United States)

2013-03-01

A beam profile monitor utilizing visible synchrotron radiation (SR) from a bending magnet has been designed and installed in Cornell Electron-Positron Storage Ring (CESR). The monitor employs a double-slit interferometer to measure both the horizontal and vertical beam sizes over a wide range of beam currents. By varying the separation of the slits, beam sizes ranging from 50 to 500 μm can be measured with a resolution of approximately 5 μm. To measure larger beam size (>500 μm), direct imaging can be employed by rotating the double slits away from SR beam path. By imaging the π-polarized component of SR, a small vertical beam size (∼70 μm) was measured during an undulator test run in CESR, which was consistent with the interferometer measurement. To measure the bunch length, a beam splitter is inserted to direct a fraction of light into a streak camera setup. This beam size monitor measures the transverse and longitudinal beam sizes simultaneously, which is successfully used for intrabeam scattering studies. Detailed error analysis is discussed.

Flatness of two-dimensional beam profile measured with an ionization chamber array

International Nuclear Information System (INIS)

Stefanovski, Z.

2006-01-01

Open beam profiles are basic dosimetric characteristics for the formation of the dose calculation algorithms parameters and for determination of beam quality. One characteristic of the beam profiles as a measure for the beam quality is the field flatness defined as ratio of the difference of maximum and minimum dose in central 80% of the field to the sum of these doses in the part of the field. The measurements, instead with an ordinary ionization chamber, were performed with a chamber array in two depths (1.6 cm and 10 cm) in water phantom. Nominal photon beam energy was 6 MV and field size was 25 cm x 25 cm on the water surface. Field flatness was in the range of 1-2 % which is in accordance with the data acquired during the acceptance testing and commissioning of the accelerators. with the array chamber the beam profiles can be performed quickly and preciously. These features recommend a chamber array as an excellent tool for periodic quality control of beam profiles. (Author)

Superconducting magnet system for the J-PARC neutrino beam line. Development, construction and operation of superconducting magnets

International Nuclear Information System (INIS)

Sasaki, Ken-ichi; Nakamoto, Tatsushi; Ajima, Yasuo; Okamura, Takahiro; Ogitsu, Toru; Kimura, Nobuhiro; Terashima, Akio; Tomaru, Takayuki; Higashi, Norio

2010-01-01

Superconducting combined-function magnets have been utilized for the 50-GeV, 750-kW proton beam line in the J-PARC neutrino experiment. The magnets are designed to provide a dipole field of 2.6 T combined with a quadrupole field of 19 T/m in a coil aperture of 173.4 mm at a nominal current of 7,345 A. Following the success of a prototype R and D project, a superconducting magnet system for the J-PARC neutrino beam line has been constructed since 2005. Using a new conceptual beam line with the superconducting combined-function magnets has demonstrated successful beam transport to the target neutrino production. (author)

Technique using axicons for generating flat-top laser-beam profiles

International Nuclear Information System (INIS)

Viswanathan, V.K.; Woodfin, G.L.; Stahl, D.; Carpenter, J.P.; Kyrala, G.

1983-01-01

In certain fusion experiments using CO 2 lasers, like Helios, it is desired to produce a focal spot several times larger than the nominal focal spot, with a flat beam profile. The typical focal spot in Helios is roughly 70 μm and just defocussing the beam produces beam breakup, with several hot spots with roughly the original diameter, and a gaussian distribution. A number of schemes were tried to achieve a large spot with desired characteristics. These are described in the article. Axicons were found to produce spots with desired characteristics. Axicons are lenses or mirrors having a cone-shaped surface. The various schemes are described, as well as an experiment in Helios which confirmed that axicons produced the spots with desirable characteristics. Helios is an 8-beam CO 2 laser which produces 10 kJ at power in excess of 20 TW. It is currently being used for Laser Fusion studies at the Los Alamos National Laboratory

Dosimetric aspects of the therapeutic photon beams from a dual-energy linear accelerator

International Nuclear Information System (INIS)

Al-Ghazi, M.S.A.L.; Arjune, B.; Fiedler, J.A.; Sharma, P.D.

1988-01-01

Parameters of the photon beams (6 and 20 MV) from a dual-energy linear accelerator (Mevatron-KD, Siemens Medical Laboratories, CA) are presented. The depth dose characteristics of the photon beams are d/sub max/ of 1.8 and 3.8 cm and percentage depth dose of 68% and 80% at 10-cm depth and 100-cm source--surface distance for a field size of 10 x 10 cm 2 for 6 and 20 MV, respectively. The 6 and 20 MV beams were found to correspond to nominal accelerating potentials of 4.7 and 17 MV, respectively. The stability of output is within +- 1% and flatness and symmetry are within +- 3%. These figures compare favorably with the manufacturer's specifications

Beam dynamics studies and emittance optimization in the CTF3 linac at CERN

CERN Document Server

Urschütz, Peter; Corsini, Roberto; Döbert, Steffen; Ferrari, Arnaud; Tecker, Frank

2006-01-01

Small transverse beam emittances and well-known lattice functions are crucial for the 30 GHz power production in the Power Extraction and Transfer Structure (PETS) and for the commissioning of the Delay Loop of the CLIC Test Facility 3 (CTF3). Following beam dynamics simulation results, two additional solenoids were installed in the CTF3 injector in order to improve the emittance. During the runs in 2005 and 2006, an intensive measurement campaign to determine Twiss parameters and beam sizes was launched. The results obtained by means of quadrupole scans for different modes of operation suggest emittances well below the nominal .n,rms = 100 ?Î?Êm and a good agreement with PARMELA simulations.

Safety Analysis of the Movable Absorber TCDQ in the LHC Beam Dumping System

CERN Document Server

Filippini, R

2009-01-01

The LHC Beam Dumping System nominally dumps the beam synchronously with the passage of the particle free beam abort gap at the beam dump extraction kickers. In the case of an asynchronous beam dump the TCDQ absorber protects the machine aperture. It is a single sided collimator, positioned close to the beam and it has to follow the beam position and beam size during the energy ramp. This report assesses the different failure scenarios of TCDQ positioning and their likelihood. The failure probability for the two TCDQ systems together is estimated to be 3.6 E-05 (mean value) for one year of LHC operation. This corresponds to a SIL4 safety level, which is considered sufficient. The three dominant failure modes are highlighted. The calculated failure probability refers to scenarios that are generated and developed inside the TCDQ system. Potential failure sources not included are the interaction with external systems: the transmission of the start signal to the PLC from a dedicated timing card and the manual opti...

Synchronous timing of multi-energy fast beam extraction during a single AGS cycle

International Nuclear Information System (INIS)

Gabusi, J.; Naase, S.

1985-01-01

Synchronous triggering of fast beams is required because the field of Kicker Magnets must rise within the open space between one beam bunch and the next. Within the Brookhaven AGS, Fast Extracted Beam (FEB) triggering combines nominal timing, based on beam energy with bunch-to-bunch synchronization, based on the accelerating rf waveform. During beam acceleration, a single bunch is extracted at 22 GeV/c and within the same AGS cycle, the remaining eleven bunches are extracted at 28.4 GeV/c. When the single bunch is extracted, a ''hole'', which is left in the remaining circulating beam, can appear in random locations within the second extraction during successive AGS cycles. To overcome this problem, a synchronous rf/12 counting scheme and logic circuitry are used to keep track of the bunch positions relative to each other, and to place the ''hole'' in any desired location within the second extraction. The rf/12 signal is used also to synchronize experimenters triggers

7 CFR 929.22 - Nomination.

Science.gov (United States)

2010-01-01

... marketing order districts as designated in § 929.20(c). (2) Six qualified persons for members and four... Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... nominations in accordance with this section. (c) Whenever any cooperative marketing organization handles more...

Gradability in the nominal domain

NARCIS (Netherlands)

Constantinescu, Camelia

2011-01-01

This dissertation investigates whether and how gradability is manifested in the nominal domain, as well as the implications this could have for theories of the representation of gradability. It is shown that the various gradability diagnostics proposed in the literature not only yield different

Study on reinforced concrete beams with helical transverse reinforcement

Science.gov (United States)

Kaarthik Krishna, N.; Sandeep, S.; Mini, K. M.

2018-02-01

In a Reinforced Concrete (R.C) structure, major reinforcement is used for taking up tensile stresses acting on the structure due to applied loading. The present paper reports the behavior of reinforced concrete beams with helical reinforcement (transverse reinforcement) subjected to monotonous loading by 3-point flexure test. The results were compared with identically similar reinforced concrete beams with rectangular stirrups. During the test crack evolution, load carrying capacity and deflection of the beams were monitored, analyzed and compared. Test results indicate that the use of helical reinforcement provides enhanced load carrying capacity and a lower deflection proving to be more ductile, clearly indicating the advantage in carrying horizontal loads. An analysis was also carried out using ANSYS software in order to compare the test results of both the beams.

Parametric study on the thermal performance of beam screen samples of the High-Luminosity LHC upgrade

Science.gov (United States)

Borges de Sousa, P.; Morrone, M.; Hovenga, N.; Garion, C.; van Weelderen, R.; Koettig, T.; Bremer, J.

2017-12-01

The High-Luminosity upgrade of the Large Hadron Collider (HL-LHC) will increase the accelerator’s luminosity by a factor 10 beyond its original design value, giving rise to more collisions and generating an intense flow of debris. A new beam screen has been designed for the inner triplets that incorporates tungsten alloy blocks to shield the superconducting magnets and the 1.9 K superfluid helium bath from incoming radiation. These screens will operate between 60 K and 80 K and are designed to sustain a nominal head load of 15 Wm-1, over 10 times the nominal heat load for the original LHC design. Their overall new and more complex design requires them and their constituent parts to be characterised from a thermal performance standpoint. In this paper we describe the experimental parametric study carried out on two principal thermal components: a representative sample of the beam screen with a tungsten-based alloy block and thermal link and the supporting structure composed of an assembly of ceramic spheres and titanium springs. Results from both studies are shown and discussed regarding their impact on the baseline considerations for the thermal design of the beam screens.

Nominal Performance Biosphere Dose Conversion Factor Analysis

International Nuclear Information System (INIS)

Wasiolek, M.

2000-01-01

The purpose of this report was to document the process leading to development of the Biosphere Dose Conversion Factors (BDCFs) for the postclosure nominal performance of the potential repository at Yucca Mountain. BDCF calculations concerned twenty-four radionuclides. This selection included sixteen radionuclides that may be significant nominal performance dose contributors during the compliance period of up to 10,000 years, five additional radionuclides of importance for up to 1 million years postclosure, and three relatively short-lived radionuclides important for the human intrusion scenario. Consideration of radionuclide buildup in soil caused by previous irrigation with contaminated groundwater was taken into account in the BDCF development. The effect of climate evolution, from the current arid conditions to a wetter and cooler climate, on the BDCF values was evaluated. The analysis included consideration of different exposure pathway's contribution to the BDCFs. Calculations of nominal performance BDCFs used the GENII-S computer code in a series of probabilistic realizations to propagate the uncertainties of input parameters into the output. BDCFs for the nominal performance, when combined with the concentrations of radionuclides in groundwater allow calculation of potential radiation doses to the receptor of interest. Calculated estimates of radionuclide concentration in groundwater result from the saturated zone modeling. The integration of the biosphere modeling results (BDCFs) with the outcomes of the other component models is accomplished in the Total System Performance Assessment (TSPA) to calculate doses to the receptor of interest from radionuclides postulated to be released to the environment from the potential repository at Yucca Mountain

Beam heating requirements for a tokamak experimental power reactor

International Nuclear Information System (INIS)

Bertoncini, P.J.; Brooks, J.N.; Fasolo, J.A.; Stacey, W.M. Jr.

1976-01-01

Typical beam heating requirements for effective tokamak experimental power reactor (TEPR) operation have been studied in connection with the Argonne preliminary conceptual TEPR design. For an ignition level plasma (approximately 100 MWt fusion power) for the nominal case envisioned, the neutral beam is only used to heat the plasma to ignition. This typically requires a beam power output of 40 MW at 180 keV for about 3 sec with a total energy of 114 MJ supplied to the plasma. The beam requirements for an ignition device are not very sensitive to changes in wall-sputtered impurity levels or plasma resistivity. For a plasma that must be driven due to poor confinement, the beam must remain on for most of the burn cycle. For representative cases, beam powers of approximately 23 MW are required for a total on-time of 20 to 50 sec. Reqirements on power level, beam energy, on-time, and beam-generation efficiency all represent considerable advances over present technology. For the Argonne TEPR design, a total of 16 to 32 beam injectors is envisioned. For a 40-MW, 180-keV, one-component beam, each injector supplies about 7 to 14 A of neutrals to the plasma. For positive ion sources, about 50 to 100 A of ions are required per injector and some form of particle and/or energy recycling appears to be essential in order to meet the power and efficiency requirements

12 CFR 1261.6 - Nominations for member and independent directorships.

Science.gov (United States)

2010-01-01

... areas: auditing and accounting, derivatives, financial management, organizational management, project... 12 Banks and Banking 7 2010-01-01 2010-01-01 false Nominations for member and independent... § 1261.6 Nominations for member and independent directorships. (a) Election announcement. Within a...

Preliminary design of electrostatic sensors for MITICA beam line components

Energy Technology Data Exchange (ETDEWEB)

Spagnolo, S., E-mail: spagnolo@igi.cnr.it; Spolaore, M.; Dalla Palma, M.; Pasqualotto, R.; Sartori, E.; Serianni, G.; Veltri, P. [Consorzio RFX, Associazione EURATOM-ENEA sulla Fusione, 35127 Padova (Italy)

2016-02-15

Megavolt ITER Injector and Concept Advancement, the full-scale prototype of ITER neutral beam injector, is under construction in Italy. The device will generate deuterium negative ions, then accelerated and neutralized. The emerging beam, after removal of residual ions, will be dumped onto a calorimeter. The presence of plasma and its parameters will be monitored in the components of the beam-line, by means of specific electrostatic probes. Double probes, with the possibility to be configured as Langmuir probes and provide local ion density and electron temperature measurements, will be employed in the neutralizer and in the residual ion dump. Biased electrodes collecting secondary emission electrons will be installed in the calorimeter with the aim to provide a horizontal profile of the beam.

The IFUSP microtron accelerator beam transport line

International Nuclear Information System (INIS)

Rios, Paulo Beolchi

2002-01-01

In this work, the electron optical project of the IFUSP microtron beam transport line is presented, including the operational values for the parameters of the dipolar and quadrupolar electromagnets, as well as their location along the beam line. Analytical calculations and computer simulations were performed to obtain these results, and a programming tool was developed in order to analyze the beam parameters and to help studying racetrack microtrons. The electron optical simulations were split into two different study cases: the microtron booster, and the transfer line. In the first case, it was determined the main operational parameters of a microtron working far from its usual stability conditions. In the latter, it was done the basic design of the linking line between the booster and main (not yet built) microtrons, and between them and the experimental hall, with a total path length of approximately 32 m including large horizontal and vertical deflections with variable beam energy. (author)

Bayesian Dimensionality Assessment for the Multidimensional Nominal Response Model

Directory of Open Access Journals (Sweden)

Javier Revuelta

2017-06-01

Full Text Available This article introduces Bayesian estimation and evaluation procedures for the multidimensional nominal response model. The utility of this model is to perform a nominal factor analysis of items that consist of a finite number of unordered response categories. The key aspect of the model, in comparison with traditional factorial model, is that there is a slope for each response category on the latent dimensions, instead of having slopes associated to the items. The extended parameterization of the multidimensional nominal response model requires large samples for estimation. When sample size is of a moderate or small size, some of these parameters may be weakly empirically identifiable and the estimation algorithm may run into difficulties. We propose a Bayesian MCMC inferential algorithm to estimate the parameters and the number of dimensions underlying the multidimensional nominal response model. Two Bayesian approaches to model evaluation were compared: discrepancy statistics (DIC, WAICC, and LOO that provide an indication of the relative merit of different models, and the standardized generalized discrepancy measure that requires resampling data and is computationally more involved. A simulation study was conducted to compare these two approaches, and the results show that the standardized generalized discrepancy measure can be used to reliably estimate the dimensionality of the model whereas the discrepancy statistics are questionable. The paper also includes an example with real data in the context of learning styles, in which the model is used to conduct an exploratory factor analysis of nominal data.

Rigidity of Nominal Wages of Non-Production Workers in Industrial Sector

Directory of Open Access Journals (Sweden)

Bambang Sulistiyono

2016-06-01

Full Text Available Excess supply of labor leads to low the levels of nominal wages received by workers. The amount of minimum wage rate exceeds the market wage rate. The determination of minimum wage is a factor manifested in the institutional and regulatory Provincial Minimum Wage or a District Minimum Wage. Unfortunately, it has made nominal wages  difficult to drop below the minimum wage level. High or low level of nominal wages are associated with worker productivity. Further, nominal wages are rigid to go down. If they have increased, they can not be dropped in the future even though the company's performance is declined. Knowing that condition, in designing the remuneration system, an employer should pay attention to the rigidity of nominal wages, so that when  company's performance declines, the company will not be interfered because of the wages burden.  Furthermore, unions and government should consider the rigidity impact of nominal wages that go down. Thus, when macroeconomic conditions deteriorate and company's performance drops, the company will not go bankrupt due to high labor costs. If the company goes bankrupt, the workers will loose their jobs as a result of employment termination, while the government will face the unemployment problem. 

Determination of Cross-Sectional Area of Focused Picosecond Gaussian Laser Beam

Science.gov (United States)

Ledesma, Rodolfo; Fitz-Gerald, James; Palmieri, Frank; Connell, John

2018-01-01

Measurement of the waist diameter of a focused Gaussian-beam at the 1/e(sup 2) intensity, also referred to as spot size, is key to determining the fluence in laser processing experiments. Spot size measurements are also helpful to calculate the threshold energy and threshold fluence of a given material. This work reports an application of a conventional method, by analyzing single laser ablated spots for different laser pulse energies, to determine the cross-sectional area of a focused Gaussian-beam, which has a nominal pulse width of approx. 10 ps. Polished tungsten was used as the target material, due to its low surface roughness and low ablation threshold, to measure the beam waist diameter. From the ablative spot measurements, the ablation threshold fluence of the tungsten substrate was also calculated.

Characteristic For Electron Beam Of A Clinac 2100 Linear Accelerator Machine

International Nuclear Information System (INIS)

Sri-Inang S; Nurman; Dani

2003-01-01

This paper describes the measurement of some dosimetric parameters for 6, 9, 12, 16 and 20 MeV electron beam of a CLINAC 2100 linear accelerator machine. The measurement were performed using Wellhofer dosimeter system at focus surface distance of 100 cm and a field size of 15 cm x 15 cm at the water phantom. The dosimetric parameter were automatically calculated from each scan. The result obtained show that the value of the depth of maximum ionization were at 1.30, 2.00, 2.66, 2.45 and 1.76 cm each for 6, 9, 12, 16 and 20 MeV nominal energy. The beam flatness varies between 0.86 to 3.68%, the beam symmetry between 0.0 to 1.55% and the penumbra between 7.4 mm to 12.4 mm. (author)

Vertical and horizontal subsidiarity

Directory of Open Access Journals (Sweden)

Ivan V. Daniluk

2016-02-01

Full Text Available This article makes an attempt to analyze the principle of subsidiarity in its two main manifestations, namely vertical and horizontal, to outline the principles of relations between the state and regions within the vertical subsidiarity, and features a collaboration of the government and civil society within the horizontal subsidiarity. Scientists identify two types, or two levels of the subsidiarity principle: vertical subsidiarity and horizontal subsidiarity. First, vertical subsidiarity (or territorial concerning relations between the state and other levels of subnational government, such as regions and local authorities; second, horizontal subsidiarity (or functional concerns the relationship between state and citizen (and civil society. Vertical subsidiarity expressed in the context of the distribution of administrative responsibilities to the appropriate higher level lower levels relative to the state structure, ie giving more powers to local government. However, state intervention has subsidiary-lower action against local authorities in cases of insolvency last cope on their own, ie higher organisms intervene only if the duties are less authority is insufficient to achieve the goals. Horizontal subsidiarity is within the relationship between power and freedom, and is based on the assumption that the concern for the common good and the needs of common interest community, able to solve community members (as individuals and citizens’ associations and role of government, in accordance horizontal subsidiarity comes to attracting features subsidiarity assistance, programming, coordination and possibly control.

Coupling Impedance of the CERN SPS beam position monitors

CERN Document Server

Salvant, B; Boccard, C; Caspers, Friedhelm; Grudiev, A; Jones, R; Métral, E; Rumolo, G; Zannini, C; Spataro, B; Alesini, D; Migliorati, M; Roncarolo, F; Calaga, R

2010-01-01

A detailed knowledge of the beam coupling impedance of the CERN Super Proton Synchrotron (SPS) is required in order to operate this machine with a higher intensity for the foreseen Large Hadron Collider (LHC) luminosity upgrade. A large number of Beam Position Monitors (BPMs) is currently installed in the SPS, and this is why their contribution to the SPS impedance has to be assessed. This paper focuses on electromagnetic (EM) simulations and bench measurements of the longitudinal and transverse impedance generated by the horizontal and vertical BPMs installed in the SPS machine.

Setting Up Simulations of Failure Scenarios for a Crab Cavity in the Nominal LHC

CERN Document Server

Yee, B

2010-01-01

The crab cavity (CC) represents a possible solution for the problem of the reduction of the luminosity due to a crossing angle. The CC apply a transversal kick on the beam particles that varies with the longitudinal position along the bunch in order to produce an effective head-head collision and to increase the geometry luminosity. For that reason the BE-ABP group at CERN has been performing studies for the implementation of the CC in the LHC. Because machine protection is a critical element of LHC operation, it is essential to study the failure scenarios of the superconducting crab cavity and the possible resulting damage impact and well as to find possible mitigation measures. For this purpose we set up simulation tools to model CC failures in the nominal LHC.

Amorphous track modelling of luminescence detector efficiency in proton and carbon beams

DEFF Research Database (Denmark)

Greilich, Steffen; Grzanka, Leszek; Bassler, Niels

assumptions in a variety of detectors. The library also includes simple particle transportation or can be interfaced to external transport codes. We applied our code to RL and OSL data from fiber-coupled Al2O3:C-detectors in a proton (nominal energies 10 MeV to 60 MeV) and a carbon beam (270 MeV/u). Results...

Multimode laser beam analyzer instrument using electrically programmable optics.

Science.gov (United States)

Marraccini, Philip J; Riza, Nabeel A

2011-12-01

Presented is a novel design of a multimode laser beam analyzer using a digital micromirror device (DMD) and an electronically controlled variable focus lens (ECVFL) that serve as the digital and analog agile optics, respectively. The proposed analyzer is a broadband laser characterization instrument that uses the agile optics to smartly direct light to the required point photodetectors to enable beam measurements of minimum beam waist size, minimum waist location, divergence, and the beam propagation parameter M(2). Experimental results successfully demonstrate these measurements for a 500 mW multimode test laser beam with a wavelength of 532 nm. The minimum beam waist, divergence, and M(2) experimental results for the test laser are found to be 257.61 μm, 2.103 mrad, 1.600 and 326.67 μm, 2.682 mrad, 2.587 for the vertical and horizontal directions, respectively. These measurements are compared to a traditional scan method and the results of the beam waist are found to be within error tolerance of the demonstrated instrument.

An Improved Beam Screen for the LHC Injection Kickers

CERN Document Server

Barnes, M J; Ducimetière, L; Garrel, N; Kroyer, T

2007-01-01

The two LHC injection kicker magnet systems must produce a kick of 1.3 T.m with a flattop duration variable up to 7860 ns, and rise and fall times of less than 900 ns and 3000 ns, respectively. Each system is composed of two resonant charging power supplies (RCPSs) and four 5 WW transmission line kicker magnets with matched terminating resistors and pulse forming networks (PFNs). A beam screen is placed in the aperture of the magnets: the screen consists of a ceramic tube with conductors on the inner wall. The conductors provide a path for the image current of the, high intensity, LHC beam and screen the ferrite against Wake fields. The conductors initially used gave adequately low beam coupling impedance however inter-conductor discharges occurred during pulsing of the magnet: an alternative design was discharge free at the nominal operating voltage but the impedance was too high for the ultimate LHC beam. This paper presents the results of a new development undertaken to meet the often conflicting requireme...

Excitation of the shear horizontal mode in a monolayer by inelastic helium atom scattering

DEFF Research Database (Denmark)

Bruch, L. W.; Hansen, Flemming Yssing

2005-01-01

Inelastic scattering of a low-energy atomic helium beam (HAS) by a physisorbed monolayer is treated in the one-phonon approximation using a time-dependent wave,packet formulation. The calculations show that modes with shear horizontal polarization can be excited near high symmetry azimuths....... The diffraction and inelastic processes arise from a strong coupling of the incident atom to the target and the calculated results show large departures from expectations based on analogies to inelastic thermal neutron scattering....

Improved waterflooding efficiency by horizontal wells

Energy Technology Data Exchange (ETDEWEB)

Popa, C. G. [Petroleum and Gas Univ., Ploesti (Romania); Clipea, M. [SNP Petrom SA, ICPT Campina (Romania)

1998-12-31

The influence of well pattern involving the use of horizontal wells on the overall efficiency of the waterflooding process was analyzed. Three different scenarios were examined: (1) a pattern of using two parallel horizontal wells, one for injection, the other for production, (2) a pattern of one horizontal well for water injection and several vertical wells for production, and (3) a pattern of using vertical wells for injection and one horizontal well for production. In each case, the waterflooding process was simulated using a two phase two dimensional numerical model. Results showed that the pressure loss along the horizontal section had a large influence on the sweep efficiency whether the horizontal well was used for injection or production. Overall, the most successful combination appeared to be using vertical wells for injection and horizontal wells for production. 4 refs., 1 tab., 15 figs.

Crystal Collimation Cleaning Measurements with Proton Beams in LHC

CERN Document Server

Rossi, Roberto; Andreassen, Odd Oyvind; Butcher, Mark; Dionisio Barreto, Cristovao Andre; Masi, Alessandro; Mirarchi, Daniele; Montesano, Simone; Lamas Garcia, Inigo; Redaelli, Stefano; Scandale, Walter; Serrano Galvez, Pablo; Rijllart, Adriaan; Valentino, Gianluca; CERN. Geneva. ATS Department

2016-01-01

During this MD, performed on July 29th, 2016, bent silicon crystal were tested with proton beams for a possible usage of crystal-assisted collimation. Tests were performed at both injection energy and flat top using horizontal and vertical crystal. Loss maps with crystals at 6.5 TeV were measured.

Cone-Beam Computed Tomography Evaluation of Mental Foramen Variations: A Preliminary Study

International Nuclear Information System (INIS)

Sheikhi, Mahnaz; Karbasi Kheir, Mitra; Hekmatian, Ehsan

2015-01-01

Background. Mental foramen is important in surgical operations of premolars because it transfers the mental nerves and vessels. This study evaluated the variations of mental foramen by cone-beam computed tomography among a selected Iranian population. Materials and Methods. A total number of 180 cone-beam computed tomography projections were analyzed in terms of shape, size, direction, and horizontal and vertical positions of mental foramen in the right and left sides. Results. The most common shape was oval, opening direction was posterior-superior, horizontal position was in line with second premolar, and vertical position was apical to the adjacent dental root. The mean of foremen diameter was 3.59 mm. Conclusion. In addition to the most common types of mental foramen, other variations exist, too. Hence, it reflects the significance of preoperative radiographic examinations, especially 3-dimensional images to prevent nerve damage

Dynamics of the off axis intense beam propagation in a spiral inflector

Energy Technology Data Exchange (ETDEWEB)

Goswami, A., E-mail: animesh@vecc.gov.in; Sing Babu, P., E-mail: psb@vecc.gov.in; Pandit, V.S., E-mail: pandit@vecc.gov.in

2017-01-01

In this paper the dynamics of space charge dominated beam in a spiral inflector is discussed by developing equations of motion for centroid and beam envelope for the off axis beam propagation. Evolution of the beam centroid and beam envelope is studied as a function of the beam current for various input beam parameters. The transmission of beam through the inflector is also estimated as a function of the beam current for an on axis and off axis beam by tracking a large number of particles. Simulation studies show that shift of the centroid from the axis at the inflector entrance affects the centroid location at the exit of the inflector and causes reduction in the beam transmission. The centroid shift at the entrance in the horizontal plane (h plane) is more critical as it affects the centroid shift in the vertical plane (u plane) by a large amount near the inflector exit where the available aperture is small. The beam transmission is found to reduce with increase in the centroid shift as well as with the beam current.

Determination of boundaries between ranges of high and low gradient of beam profile.

Science.gov (United States)

Wendykier, Jacek; Bieniasiewicz, Marcin; Grządziel, Aleksandra; Jedynak, Tadeusz; Kośniewski, Wiktor; Reudelsdorf, Marta; Wendykier, Piotr

2016-01-01

This work addresses the problem of treatment planning system commissioning by introducing a new method of determination of boundaries between high and low gradient in beam profile. The commissioning of a treatment planning system is a very important task in the radiation therapy. One of the main goals of this task is to compare two field profiles: measured and calculated. Applying points of 80% and 120% of nominal field size can lead to the incorrect determination of boundaries, especially for small field sizes. The method that is based on the beam profile gradient allows for proper assignment of boundaries between high and low gradient regions even for small fields. TRS 430 recommendations for commissioning were used. The described method allows a separation between high and low gradient, because it directly uses the value of the gradient of a profile. For small fields, the boundaries determined by the new method allow a commissioning of a treatment planning system according to the TRS 430, while the point of 80% of nominal field size is already in the high gradient region. The method of determining the boundaries by using the beam profile gradient can be extremely helpful during the commissioning of the treatment planning system for Intensity Modulated Radiation Therapy or for other techniques which require very small field sizes.

New wiggler beam line for SSRL

International Nuclear Information System (INIS)

Hoyer, E.

1982-08-01

A new high-intensity-beam line with a wiggler magnet source is described. This project, in final stages of design, is a joint effort between Lawrence Berkeley Laboratory (LBL), the Exxon Research and Engineering Company (EXXON), and the Stanford Synchrotron Radiation Laboratory (SSRL). Installation at SSRL will begin in the summer of 1982. The goal of this project is to provide extremely high-brightness synchrotron radiation beams over a broad spectral range from 50 eV to 40 keV. The radiation source is a 27 period (i.e., 55 pole) permanent magnet wiggler of a new design. The wiggler utilizes rare-earth cobalt (REC) material in the steel hybrid configuration to achieve high magnetic fields with short periods. An analysis has been made of the polarization, angular distribution and power density of the radiation produced by the wiggler. Details of the wiggler design are presented. The magnet is outside a thin walled (1mm) variable gap stainless steel vacuum chamber. The chamber gap will be opened to 1.8 cm for beam injection into SPEAR and then closed to 1.0 cm (or less) for operation. Five remotely controlled drives are provided; to change the wiggler gap, to change the vacuum chamber aperture and to position the wiggler. Details of the beam line optics and end stations are presented. Thermal loading on beam line components is severe. The peak power density at 7.5 m is 5 kW/cm 2 for the nominal wiggler field and present SPEAR beam currents and will approach 20 kW/cm 2 with the maximum wiggler field and projected SPEAR beam currents

Dynamic analysis of horizontal axis wind turbine by thin-walled beam theory

Science.gov (United States)

Wang, Jianhong; Qin, Datong; Lim, Teik C.

2010-08-01

A mixed flexible-rigid multi-body mathematical model is applied to predict the dynamic performance of a wind turbine system. Since the tower and rotor are both flexible thin-walled structures, a consistent expression for their deformations is applied, which employs a successive series of transformations to locate any point on the blade and tower relative to an inertial coordinate system. The kinetic and potential energy terms of each flexible body and rigid body are derived for use in the Lagrange approach to formulate the wind turbine system's governing equation. The mode shapes are then obtained from the free vibration solution, while the distributions of dynamic stress and displacement of the tower and rotor are computed from the forced vibration response analysis. Using this dynamic model, the influence of the tower's stiffness on the blade tip deformation is studied. From the analysis, it is evident that the proposed model not only inherits the simplicity of the traditional 1-D beam element, but also able to provide detailed information about the tower and rotor response due to the incorporation of the flexible thin-walled beam theory.

MONOTONIC AND CYCLIC LOADING SIMULATION OF STRUCTURAL STEELWORK BEAM TO COLUMN BOLTED CONNECTIONS WITH CASTELLATED BEAM

Directory of Open Access Journals (Sweden)

SAEID ZAHEDI VAHID

2013-08-01

Full Text Available Recently steel extended end plate connections are commonly used in rigid steel frame due to its good ductility and ability for energy dissipation. This connection system is recommended to be widely used in special moment-resisting frame subjected to vertical monotonic and cyclic loads. However improper design of beam to column connection can leads to collapses and fatalities. Therefore extensive study of beam to column connection design must be carried out, particularly when the connection is exposed to cyclic loadings. This paper presents a Finite Element Analysis (FEA approach as an alternative method in studying the behavior of such connections. The performance of castellated beam-column end plate connections up to failure was investigated subjected to monotonic and cyclic loading in vertical and horizontal direction. The study was carried out through a finite element analysis using the multi-purpose software package LUSAS. The effect of arranging the geometry and location of openings were also been investigated.

Determination of nominal accelerating potential

International Nuclear Information System (INIS)

Nizin, P.; Kase, K.

1986-01-01

We present a simple linear relationship between the nominal accelerating potential (NAP) and the ratios of ionization measurements made with constant source--detector distance and at two different phantom thicknesses. This relationship can be used as a standard, unambiguous method for determining NAP for use in dosimetry and quality control

The processing of raising and nominal control: An eye-tracking study

Directory of Open Access Journals (Sweden)

Patrick eSturt

2015-03-01

Full Text Available According to some views of sentence processing, the memory retrieval processes involved in dependency formation may differ as a function of the type of dependency involved. For example, using closely matched materials in a single experiment Dillon et al (2013 found evidence for retrieval interference in subject-verb agreement, but not in reflexive-antecedent agreement. We report four eye-tracking experiments that examine examine reflexive-antecedent dependencies, combined with raising (e.g. ``John seemed to Tom to be kind to himself...'', or nominal control (e.g. ``John’s agreement with Tom to be kind to himself...''. We hypothesized that dependencies involving raising would (a be processed more quickly, and (b be less subject to retrieval interference, relative to those involving nominal control. This is due to the fact that the interpretation of raising is structurally constrained, while the interpretation of nominal control depends crucially on lexical properties of the control nominal. The results showed evidence of interference when the reflexive-antecedent dependency was mediated by raising or nominal control, but very little evidence that could be interpreted in terms of interference for direct reflexive-antecedent dependencies that did not involve raising or control. However, there was no evidence either for greater interference, or for quicker dependency formation, for raising than for nominal control.

Tests of Local Hadron Calibration Approaches in ATLAS Combined Beam Tests

International Nuclear Information System (INIS)

Grahn, Karl-Johan; Kiryunin, Andrey; Pospelov, Guennadi

2011-01-01

Three ATLAS calorimeters in the region of the forward crack at |η| 3.2 in the nominal ATLAS setup and a typical section of the two barrel calorimeters at |η| = 0.45 of ATLAS have been exposed to combined beam tests with single electrons and pions. Detailed shower shape studies of electrons and pions with comparisons to various Geant4 based simulations utilizing different physics lists are presented for the endcap beam test. The local hadron calibration approach as used in the full Atlas setup has been applied to the endcap beam test data. An extension of it using layer correlations has been tested with the barrel test beam data. Both methods utilize modular correction steps based on shower shape variables to correct for invisible energy inside the reconstructed clusters in the calorimeters (compensation) and for lost energy deposits outside of the reconstructed clusters (dead material and out-of-cluster deposits). Results for both methods and comparisons to Monte Carlo simulations are presented.

77 FR 50987 - Environmental Technologies Trade Advisory Committee, Request for Nominations

Science.gov (United States)

2012-08-23

... DEPARTMENT OF COMMERCE International Trade Administration Environmental Technologies Trade... Commerce. ACTION: Solicitation of Nominations for Membership on the Environmental Technologies Trade...) is requesting nominations for memberships on the Environmental Technologies Trade Advisory Committee...

2-D Low Energy Electron Beam Profile Measurement Based on Computer Tomography Algorithm with Multi-Wire Scanner

CERN Document Server

Yu, Nengjie; Li Qing Feng; Tang, Chuan-Xiang; Zheng, Shuxin

2005-01-01

A new method for low energy electron beam profile measurement is advanced, which presents a full 2-D beam profile distribution other than the traditional 2-D beam profile distribution given by 1-D vertical and horizontal beam profiles. The method is based on the CT (Computer Tomography) algorithm. Multi-sets of data about the 1-D beam profile projections are attained by rotating the multi-wire scanner. Then a 2-D beam profile is reconstructed from these projections with CT algorithm. The principle of this method is presented. The simulation and the experiment results are compared and analyzed in detail.

Optical method for mapping the transverse phase space of a charged particle beam

International Nuclear Information System (INIS)

Fiorito, R.B.; Shkvarunets, A.G.; O'Shea, P.G.

2002-01-01

We are developing an all optical method to map the transverse phase space map of a charged particle beam. Our technique employs OTR interferometry (OTRI) in combination with a scanning pinhole to make local orthogonal (x,y) divergence and trajectory angle measurements as function of position within the transverse profile of the beam. The localized data allows a reconstruction of the horizontal and vertical phase spaces of the beam. We have also demonstrated how single and multiple pinholes can in principle be used to make such measurements simultaneously

45 CFR 1801.10 - Nomination by institution of higher education.

Science.gov (United States)

2010-10-01

... 45 Public Welfare 4 2010-10-01 2010-10-01 false Nomination by institution of higher education. 1801.10 Section 1801.10 Public Welfare Regulations Relating to Public Welfare (Continued) HARRY S... institution of higher education. To be considered in the competition a student must be nominated by the...

Measurements of electron beam emittance in the Accelerator Test Facility damping ring operated in multibunch modes

Directory of Open Access Journals (Sweden)

Yosuke Honda

2003-09-01

Full Text Available We present the measurement results of electron beam emittance in the Accelerator Test Facility damping ring operated in multibunch modes. The measurements were carried out with an upgraded laser wire beam profile monitor. The monitor has now a vertical wire as well as a horizontal one and is able to make much faster measurements thanks to an increased effective laser power inside the cavity. The measured emittance shows no large bunch-to-bunch dependence in either the horizontal or vertical directions. The values of the vertical emittance are similar to those obtained in the single-bunch operation. The present results are an important step toward the realization of a high-energy linear collider.

Beam-beam interaction and Pacman effects in the SSC with random nonlinear multipoles

International Nuclear Information System (INIS)

Goderre, G.P.; Ohnuma, S.

1988-01-01

In order to find the combined effects of beam-beam interaction (head-on and long-range) and random nonlinear multipoles in dipole magnets, transverse tunes and smears have been calculated as a function of oscillation amplitudes. Two types of particles, ''regular'' and ''Pacman,'' have been investigated using a modified version of tracking code TEAPOT. Regular particles experience beam-beam interactions in all four interaction regions (IR's), both head-on and long range, while pacman particles interact with bunches of the other beam in one medium-beta and one low-beta IR's only. The model for the beam-beam interaction is of weak-strong type and the strong beam is assumed to have a round Gaussian charge distribution. Furthermore, it is assumed that the vertical closed orbit deviation arising from the finite crossing angle of 70 μrad is perfectly compensated for regular particles. The same compensation applied to pacman particles creates a closed orbit distortion. Linear tunes are adjusted for regular particles to the design values but there are no nonlinear corrections except for chromaticity correcting sextupoles in two families. Results obtained in this study do not show any reduction of dynamic or linear aperture for pacman particles but some doubts exist regarding the validity of defining the linear aperture from the smear alone. Preliminary results are given for regular particles when (Δp/p) is modulated by the synchrotron oscillation. For these, fifty oscillations corresponding to 26,350 revolutions have been tracked. A very slow increase in the horizontal amplitude, /approximately/4 /times/ 10/sup /minus/4//oscillation (relative), is a possibility but this should be confirmed by trackings of larger number of revolutions. 11 refs., 18 figs., 2 tabs

PSR experience with beam losses, instabilities and space charge effects

International Nuclear Information System (INIS)

Macek, Robert J.

1998-01-01

Average current from the PSR has been limited to ∼70 μA at 20 Hz by beam losses of 0.4 to 0.5 μA which arise from two principal causes, production of H 0 excited states and stored-beam scattering in the stripper foil. To reduce beam losses, an upgrade from the two-step H 0 injection to direct H - injection is underway and will be completed in 1998. Peak intensity from the PSR is limited by a strong instability that available evidence indicates is the two-stream e-p instability. New evidence for the e-p hypothesis is presented. At operating intensities, the incoherent space charge tune shift depresses both horizontal and vertical tunes past the integer without additional beam loss although some intensity-dependent emittance growth is observed

Very Fast Losses of the Circulating LHC Beam, their Mitigation and Machine Protection

CERN Document Server

Baer, Tobias; Elsen, Eckhard

The Large Hadron Collider (LHC) has a nominal energy of 362MJ stored in each of its two counter-rotating beams - over two orders of magnitude more than any previous accelerator and enough to melt 880kg of copper. Therefore, in case of abnormal conditions comprehensive machine protection systems extract the beams safely from the LHC within not more than three turns $\\approx$270$\\mu$s. The first years of LHC operation demonstrated a remarkable reliability of the major machine protection systems. However, they also showed that the LHC is vulnerable to losses of the circulating beams on very fast timescales, which are too fast to ensure an active protection. Very fast equipment failures, in particular of normal-conducting dipole magnets and the transverse damper can lead to such beam losses. Whereas these failures were already studied in the past, other unexpected beam loss mechanisms were observed after the LHC start-up: so-called (un)identified falling objects (UFOs), which are believed to be micrometer-sized m...

Ion movie camera for particle-beam-fusion experiments

International Nuclear Information System (INIS)

Stygar, W.A.; Mix, L.P.; Leeper, R.J.; Maenchen, J.; Wenger, D.F.; Mattson, C.R.; Muron, D.J.

1992-01-01

A camera with a 3 ns time resolution and a continuous (>100 ns) record length has been developed to image a 10 12 --10 13 W/cm 2 ion beam for inertial-confinement-fusion experiments. A thin gold Rutherford-scattering foil placed in the path of the beam scatters ions into the camera. The foil is in a near-optimized scattering geometry and reduces the beam intensity∼seven orders of magnitude. The scattered ions are pinhole imaged onto a 2D array of 39 p-i-n diode detectors; outputs are recorded on LeCroy 6880 transient-waveform digitizers. The waveforms are analyzed and combined to produce a 39-pixel movie which can be displayed on an image processor to provide time-resolved horizontal- and vertical-focusing information

Beam based alignment and its relevance in Indus-2

Energy Technology Data Exchange (ETDEWEB)

Jena, Saroj Kumar; Husain, Riyasat; Gandhi, M. L.; Agrawal, R. K.; Yadav, S.; Ghodke, A. D. [Raja Ramanna Centre for Advanced Technology, Indore (India)

2015-09-15

Initially in the Indus-2 storage ring, the closed orbit distortion (COD) could be best corrected to 1.3 mm rms in the horizontal and 0.43 mm rms in the vertical plane. The strength of the corrector magnets required high values for COD correction. This revealed that offsets in COD readout by the beam position monitors (BPMs) played a role in not achieving a rms COD lower than the above value. Thus, the offset between the electrical center of BPMs and the magnetic center of the nearest quadrupole magnet could be estimated using the beam based alignment (BBA) method. It prefers that the quadrupole magnet is able to be controlled individually and active shunt power supply (ASPS) system was designed for this purpose that works efficiently. This paper describes the methodology of BBA, topology of ASPS and its performance, and COD minimization using the measured BPM offsets. After BBA, the COD could be reduced to 0.45 mm rms and 0.2 mm rms in horizontal and vertical planes, respectively.

Beam based alignment and its relevance in Indus-2

Science.gov (United States)

Jena, Saroj Kumar; Husain, Riyasat; Gandhi, M. L.; Agrawal, R. K.; Yadav, S.; Ghodke, A. D.

2015-09-01

Initially in the Indus-2 storage ring, the closed orbit distortion (COD) could be best corrected to 1.3 mm rms in the horizontal and 0.43 mm rms in the vertical plane. The strength of the corrector magnets required high values for COD correction. This revealed that offsets in COD readout by the beam position monitors (BPMs) played a role in not achieving a rms COD lower than the above value. Thus, the offset between the electrical center of BPMs and the magnetic center of the nearest quadrupole magnet could be estimated using the beam based alignment (BBA) method. It prefers that the quadrupole magnet is able to be controlled individually and active shunt power supply (ASPS) system was designed for this purpose that works efficiently. This paper describes the methodology of BBA, topology of ASPS and its performance, and COD minimization using the measured BPM offsets. After BBA, the COD could be reduced to 0.45 mm rms and 0.2 mm rms in horizontal and vertical planes, respectively.

Horizontal drilling assessment in Western Canada

International Nuclear Information System (INIS)

Catania, Peter; Wilson, Malcolm

1999-01-01

The first horizontal well was drilled in Saskatchewan in 1987. Since then, the number of horizontal wells drilled has escalated rapidly, averaging approximately 500 per year since 1993. When combined with horizontal wells drilled in Alberta, the major Canadian oil-producing province, the total number drilled in 1995 was 978. This total exceeds the National Energy Board (NEB) projected maximum of 816 wells per year. The NEB projections were based on a break-even point for the drilling of horizontal wells of a return of CDN $285,000 using a discount rate of 15%. This corresponded to a cumulative production from each individual well of some 11,000 m 3 . The introduction of a royalty-free production volume of 12,000 m 3 per horizontal well in Saskatchewan was instrumental in stimulating the rapid expansion in the use of horizontal wells and helping Canada to exceed the forecasted drilling level. Within Saskatchewan, daily production from 1964 active horizontal wells is in excess of 20,000 m 3 . Comparative analysis indicates that the average daily production per well has increased from approximately by 40% with the advent of horizontal wells. In total production terms, provincial production has increased from 11.7 million cubic metres in 1989 to 20.9 million m 3 in 1996. This represents an increase of almost 79% based primarily on the extensive use of horizontal wells. In 1996, horizontal wells produced 36% of the province's oil from 12% of the active wells. In the southeastern producing areas of Saskatchewan, the Williston Basin, declining oil-production has jumped 100%, with horizontal wells accounting for approximately 50% of total regional production. Pay zones in this areas, as in most of the province, tend to be relatively thin, with net pay frequently less that 5 m. The modest investment of some CDN $5 million in government research funding 10 years ago to stimulate the development of horizontal wells, combined with a favourable royalty structure, has been at

Development of a Charged Particle Microbeam for Single-Particle Subcellular Irradiations at the MIT Laboratory for Accelerator Beam Application

International Nuclear Information System (INIS)

Yanch, Jacquelyn C.

2004-01-01

The development of a charged particle microbeam for single particle, subcellular irradiations at the Massachusetts Institute of Technology Laboratory for Accelerator Beam Applications (MIT LABA) was initiated under this NEER aeard. The Microbeam apparatus makes use of a pre-existing electrostatic accelerator with a horizontal beam tube

Russian nominal semantics and morphology

DEFF Research Database (Denmark)

Nørgård-Sørensen, Jens

The principal idea behind this book is that lexis and grammar make up a single coherent structure. It is shown that the grammatical patterns of the different classes of Russian nominals are closely interconnected. They can be described as reflecting a limited set of semantic distinctions which ar...... or weaker, of Russian. Students will see a pattern in what is traditionally described as disparate subsystems, and linguists may be inspired to consider the theoretical points concerning language as a coherent system, determining usage.......The principal idea behind this book is that lexis and grammar make up a single coherent structure. It is shown that the grammatical patterns of the different classes of Russian nominals are closely interconnected. They can be described as reflecting a limited set of semantic distinctions which...... are also rooted in the lexical-semantic classification of Russian nouns. The presentation focuses on semantics, both lexical and grammatical, and not least the connection between these two levels of content. The principal theoretical impact is the insight that grammar and lexis should not be seen...

The influence of the solar radiation model on the calcutated solar radiation from a horizontal surface to a tilted surface

DEFF Research Database (Denmark)

Andersen, Elsa; Lund, Hans; Furbo, Simon

2004-01-01

Measured solar radiation data are most commonly available as total solar radiation on a horizontal surface. When using solar radiation measured on horizontal to calculate the solar radiation on tilted surfaces and thereby the thermal performance of different applications such as buildings and solar...... heating systems, different solar radiation models can be used. The calculation of beam radiation from a horizontal surface to a tilted surface can be done exactly whereas different solar radiation models can calculate the sky diffuse radiation. The sky diffuse radiation can either be assumed evenly...... in the calculation. The weather data are measured at the solar radiation measurement station, SMS at the Department of Civil Engineering at the Technical University of Denmark. In this study the weather data are combined with solar collector calculations based on solar collector test carried out at Solar Energy...

Long pulse characteristics of 5 MW ion source for SST-1 neutral beam injector

Energy Technology Data Exchange (ETDEWEB)

Jana, M.R. [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)], E-mail: mukti@ipr.res.in; Mattoo, S.K.; Chakraborty, A.K.; Baruah, U.K.; Patel, G.B.; Jayakumar, P.K. [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)

2008-10-15

We present characteristics of a 5 MW ion source for SST-1 neutral beam injector. Before the source could be tested for its performance, it was conditioned by 480 arc discharges of 1 s and beam extraction of hydrogen species at various beam voltages ranging between 19 kV and 56 kV. Breakdown free beam extraction could be secured only after about 3000 beam second extraction. The ion source is capable of delivering 1.7 MW of neutral beam power at 55 kV with horizontal and vertical focal length of 5.4 m and 7 m respectively. Beam divergence is {approx}0.97 deg. Steady-state beam energy of 31 MJ at 41 kV was achieved during 14 s long beam extraction. We have not noticed any deterioration of beam parameters, including beam divergence during long pulse operation. These results indicate that 0.5 MW of neutral beam power at 30 kV required for heating of plasma in SST-1 can be delivered.

Long pulse characteristics of 5 MW ion source for SST-1 neutral beam injector

International Nuclear Information System (INIS)

Jana, M.R.; Mattoo, S.K.; Chakraborty, A.K.; Baruah, U.K.; Patel, G.B.; Jayakumar, P.K.

2008-01-01

We present characteristics of a 5 MW ion source for SST-1 neutral beam injector. Before the source could be tested for its performance, it was conditioned by 480 arc discharges of 1 s and beam extraction of hydrogen species at various beam voltages ranging between 19 kV and 56 kV. Breakdown free beam extraction could be secured only after about 3000 beam second extraction. The ion source is capable of delivering 1.7 MW of neutral beam power at 55 kV with horizontal and vertical focal length of 5.4 m and 7 m respectively. Beam divergence is ∼0.97 deg. Steady-state beam energy of 31 MJ at 41 kV was achieved during 14 s long beam extraction. We have not noticed any deterioration of beam parameters, including beam divergence during long pulse operation. These results indicate that 0.5 MW of neutral beam power at 30 kV required for heating of plasma in SST-1 can be delivered.

76 FR 76732 - Nominations to the Advisory Committee on Blood Safety and Availability

Science.gov (United States)

2011-12-08

... individuals will be nominated to the Secretary of HHS for consideration of appointment as members of the ACBSA..., Associate Public Health Advisor for Blood, Organ and Tissue Safety Policy, Department of Health and Human.... Nominations In accordance with the charter, persons nominated for appointment as members of the ACBSA should...

76 FR 5424 - Motor Carrier Safety Advisory Committee; Request for Nominations

Science.gov (United States)

2011-01-31

... DEPARTMENT OF TRANSPORTATION Federal Motor Carrier Safety Administration [Docket No. FMCSA-2006-26367] Motor Carrier Safety Advisory Committee; Request for Nominations AGENCY: Federal Motor Carrier Safety Administration (FMCSA), DOT. ACTION: Request for Nominations to the Motor Carrier Safety Advisory...

A dynamic model for beam tube vacuum effects on the SSC cryogenic system

International Nuclear Information System (INIS)

Carcagno, R.H.; Schiesser, W.E.; Shih, H.J.; Xu, X.; Yuecel, A.

1992-01-01

The dynamic interaction between the beam-gas scattering induced energy deposition and the SSC cryogenic system is studied by integrating a cryogenic system dynamic simulator with an adsorption model and a beam-gas scattering and energy deposition model. Simulation results are obtained for a 1km long SSC arc section where the beam tube pressure in one of the dipoles is increased up to 150 times its nominal operating pressure. The beam-gas scattering induced heat loads arising from such high pressure perturbations can be very high locally but do not overload the cryogenic system. They are more likely to induce a magnet quench as they result in coil temperatures that largely exceed the desired operating limit. Simulations are also carried out for the case where a large external heat load of 1W/m is imposed on the coldmass of a half-cell in the section. Results show that the coldmass temperatures rise significantly with the added heat load but the energy deposition in the cold mass due to beam-gas scattering remains low despite the increase in the beam tube temperature

A dynamic model for beam tube vacuum effects on the SSC cryogenic system

International Nuclear Information System (INIS)

Carcagno, R.H.; Schiesser, W.E.; Shih, H.J.; Xu, X.; Yuecel, A.

1992-03-01

The dynamic interaction between the beam-gas scattering induced energy deposition and the SSC cryogenic system is studied by integrating a cryogenic system dynamic simulator with an adsorption model and a beam-gas scattering and energy deposition model. Simulation results are obtained for a 1 km long SSC arc section where the beam tube pressure in one of the dipoles in increased up to 150 times its nominal operating pressure. The beam-gas scattering induced heat loads arising from such high pressure perturbations can be very locally but do not overload the cryogenic system. They are more likely to induce a magnet quench as they result in coil temperatures that largely exceed the desired operating limit. Simulations are also carried out for the case where a large external heat load of 1 W/m is imposed on the coldmass of a half-cell in the section. Results show that the coldmass temperatures rise significantly with the added heat load but the energy deposition in the coldmass due to beam-gas scattering remains low despite the increase in the beam tube temperature

Electron Beam Alignment Strategy in the LCLS Undulators

International Nuclear Information System (INIS)

Nuhn, H

2007-01-01

The x-ray FEL process puts very tight tolerances on the straightness of the electron beam trajectory (2 (micro)m rms) through the LCLS undulator system. Tight but less stringent tolerances of 80 (micro)m rms vertical and 140 (micro)m rms horizontally are to be met for the placement of the individual undulator segments with respect to the beam axis. The tolerances for electron beam straightness can only be met through beam-based alignment (BBA) based on electron energy variations. Conventional alignment will set the start conditions for BBA. Precision-fiducialization of components mounted on remotely adjustable girders and the use of beam-finder wires (BFW) will satisfy placement tolerances. Girder movement due to ground motion and temperature changes will be monitored continuously by an alignment monitoring system (ADS) and remotely corrected. This stabilization of components as well as the monitoring and correction of the electron beam trajectory based on BPMs and correctors will increase the time between BBA applications. Undulator segments will be periodically removed from the undulator Hall and measured to monitor radiation damage and other effects that might degrade undulator tuning

Source Terms for HFIR Beam Tube Shielding Analyses, and a Complete Shielding Analysis of the HB-3 Tube

International Nuclear Information System (INIS)

Bucholz, J.A.

2000-01-01

The High Flux Isotope Reactor (HFIR) at the Oak Ridge National Laboratory is in the midst of a massive upgrade program to enhance experimental facilities. The reactor presently has four horizontal experimental beam tubes, all of which will be replaced or redesigned. The HB-2 beam tube will be enlarged to support more guide tubes, while the HB-4 beam tube will soon include a cold neutron source

Source Terms for HFIR Beam Tube Shielding Analyses, and a Complete Shielding Analysis of the HB-3 Tube

Energy Technology Data Exchange (ETDEWEB)

Bucholz, J.A.

2000-07-01

The High Flux Isotope Reactor (HFIR) at the Oak Ridge National Laboratory is in the midst of a massive upgrade program to enhance experimental facilities. The reactor presently has four horizontal experimental beam tubes, all of which will be replaced or redesigned. The HB-2 beam tube will be enlarged to support more guide tubes, while the HB-4 beam tube will soon include a cold neutron source.

Safe Laser Beam Propagation for Interplanetary Links

Science.gov (United States)

Wilson, Keith E.

2011-01-01

Ground-to-space laser uplinks to Earth–orbiting satellites and deep space probes serve both as a beacon and an uplink command channel for deep space probes and Earth-orbiting satellites. An acquisition and tracking point design to support a high bandwidth downlink from a 20-cm optical terminal on an orbiting Mars spacecraft typically calls for 2.5 kW of 1030-nm uplink optical power in 40 micro-radians divergent beams.2 The NOHD (nominal ocular hazard distance) of the 1030nm uplink is in excess of 2E5 km, approximately half the distance to the moon. Recognizing the possible threat of high power laser uplinks to the flying public and to sensitive Earth-orbiting satellites, JPL developed a three-tiered system at its Optical Communications Telescope Laboratory (OCTL) to ensure safe laser beam propagation through navigational and near-Earth space.

Turbulence-induced persistence in laser beam wandering.

Science.gov (United States)

Zunino, Luciano; Gulich, Damián; Funes, Gustavo; Pérez, Darío G

2015-07-01

We have experimentally confirmed the presence of long-memory correlations in the wandering of a thin Gaussian laser beam over a screen after propagating through a turbulent medium. A laboratory-controlled experiment was conducted in which coordinate fluctuations of the laser beam were recorded at a sufficiently high sampling rate for a wide range of turbulent conditions. Horizontal and vertical displacements of the laser beam centroid were subsequently analyzed by implementing detrended fluctuation analysis. This is a very well-known and widely used methodology to unveil memory effects from time series. Results obtained from this experimental analysis allow us to confirm that both coordinates behave as highly persistent signals for strong turbulent intensities. This finding is relevant for a better comprehension and modeling of the turbulence effects in free-space optical communication systems and other applications related to propagation of optical signals in the atmosphere.

Increased power delivery from the DIII-D neutral beam injection system

International Nuclear Information System (INIS)

Colleraine, A.P.; Callis, R.W.; Hong, R.M.; Kellman, D.H.; Kim, J.; Langhorn, A.R.; Lee, R.; Phillips, J.C.; Wight, J.J.

1989-12-01

The neutral beam system installed on the DIII-D tokamak employs eight 80 kV Long Pulse Sources (LPS) mounted on four beamlines and was originally designed to deliver a nominal 12 MW of H degree power to a plasma for pulses of up to 5 sec duration. Lawrence Berkeley Laboratory designed the LPS for the US Fusion Program to fill the requirements of both the DIII-D and the TFTR machines. Essentially all source components are of a common design; the DIII-D version is therefore conservative in its rated parameters. Recently a neutron shield has been constructed around the torus hall allowing D degree injection to become routine. Because deuterium beams have a better neutralization efficiency, the nominal power delivery per source has been measured to be approximately 2 MW (for a total of 16 MW) without any modifications. However, by reoptimizing the voltage gradients in the source, the perveance can be increased without degrading the optics. A change of gradient grid voltage from 0.83 V accel to 0.79 V accel raises the perveance from 2.5 to 3.0 μPerv with a corresponding gain in beam power of about 20%. The arc power required also must be increased to the range of 100 to 120 kW but this is well within the design limits of the LPS. Further studies of our systems are now underway to assess the possibilities of raising V accel above 80 kV. An additional gain in power is possible by this technique. 6 refs., 6 figs

Single-beam measurements of LHC instability threshold in terms of octupole current

CERN Document Server

Mounet, N; Buffat, X; Burov, A; Hemelsoet, G; Metral, E; Papotti, G; Pieloni, T; Pojer, M; Salvant, B; Trad, G

2012-01-01

This note summarizes two machine development (MD) studies aimed at determining the octupole current needed in the LHC in order to stabilize all headtail instabilities at 4TeV/c, before and after the squeeze, with tight collimator settings, and when a single beam (beam 2) at maximum intensity (1380 bunches, 2.1 1014 protons) is present in the machine. The MDs followed the normal physics operation procedure, at the notable exception that a single beam was used, the other beam containing only one non-colliding nominal bunch. Octupole current (with negative polarity in the focusing octupoles and the opposite in the defocusing ones) was decreased by small steps until the instability threshold was reached. This was performed in two distinct MDs, one before the squeeze and the other after it, testing also several chromaticity values and the effect of the transverse damper in the latter case. Octupole thresholds are shown in each case studied, as well as the rise times of the instabilities observed.

Behavior of bonded and unbonded prestressed normal and high strength concrete beams

Directory of Open Access Journals (Sweden)

O.F. Hussien

2012-12-01

This paper presents an experimental program conducted to study the behavior of bonded and unbounded prestressed normal strength (NSC and high strength concrete (HSC beams. The program consists of a total of nine beams; two specimens were reinforced with non-prestressed reinforcement, four specimens were reinforced with bonded tendons, and the remaining three specimens were reinforced with unbonded tendons. The overall dimensions of the beams are 160 × 340 × 4400-mm. The beams were tested under cyclic loading up to failure to examine its flexural behavior. The main variables in this experimental program are nominal concrete compressive strength (43, 72 and 97 MPa, bonded and unbonded tendons and prestressing index (0%, 70% and 100%. Theoretical analysis using rational approach was also carried out to predict the flexural behavior of the specimens. Evaluation of the analytical work is introduced and compared to the results of the experimental work.

Beam Optics for FCC-ee Collider Ring

CERN Document Server

Oide, Katsunobu; Aumon, S; Benedikt, M; Blondel, A; Bogomyagkov, A V; Boscolo, M; Burkhardt, H; Cai, Y; Doblhammer, A; Haerer, B; Holzer, B; Koop, I; Koratzinos, M; Jowett, John M; Levichev, E B; Medina, L; Ohmi, K; Papaphilippou, Y; Piminov, P A; Shatilov, D N; Sinyatkin, S V; Sullivan, M; Wenninger, J; Wienands, U; Zhou, D; Zimmermann, F

2017-01-01

A beam optics scheme has been designed [ 1 ] for the Future Circular Collider- e + e − (FCC-ee). The main characteristics of the design are: beam energy 45 to 175 GeV, 100 km circumference with two interaction points (IPs) per ring, horizontal crossing angle of 30 mrad at the IP and the crab-waist scheme [ 2 ] with local chromaticity correction. The crab-waist scheme is implemented within the local chromaticity correction system without additional sextupoles, by reducing the strength of one of the two sextupoles for vertical chromatic correction at each side of the IP. So- called “tapering" of the magnets is applied, which scales all fields of the magnets according to the local beam energy to compensate for the effect of synchrotron radiation (SR) loss along the ring. An asymmetric layout near the interaction region reduces the critical energy of SR photons on the incoming side of the IP to values below 100 keV, while matching the geometry to the beam line of the FCC proton collider (FCC-hh) [ 3 ] as clos...

Targeting nominal income growth or inflation?

DEFF Research Database (Denmark)

Jensen, Henrik

2002-01-01

Within a simple New Keynesian model emphasizing forward-looking behavior of private agents, I evaluate optimal nominal income growth targeting versus optimal inflation targeting. When the economy is mainly subject to shocks that do not involve monetary policy trade-offs for society, inflation...

Regular and context-free nominal traces

DEFF Research Database (Denmark)

Degano, Pierpaolo; Ferrari, Gian-Luigi; Mezzetti, Gianluca

2017-01-01

Two kinds of automata are presented, for recognising new classes of regular and context-free nominal languages. We compare their expressive power with analogous proposals in the literature, showing that they express novel classes of languages. Although many properties of classical languages hold ...

Data evaluation and CNGS beam localization with the precision tracker of the OPERA detector

International Nuclear Information System (INIS)

Bick, D.

2007-04-01

In this diploma thesis, the data evaluation for the OPERA precision tracker is presented. Furthermore investigations of a precise CNGS beam localization with the precision tracker are performed. After an overview of past and present developments in neutrino physics, the OPERA detector is presented in this thesis. Emphasis is given to the precision tracker which has been partly commissioned in the end of the last year. A first analysis of the functionality with cosmic muons has been performed, as well as the inclusion of data in the OPERA software framework. Within this thesis some useful tools have been developed which are also presented. Finally, divergence effects from the nominal beam line of the CNGS neutrino beam and possible detection with the precision tracker are studied. (orig.)

Data evaluation and CNGS beam localization with the precision tracker of the OPERA detector

Energy Technology Data Exchange (ETDEWEB)

Bick, D.

2007-04-15

In this diploma thesis, the data evaluation for the OPERA precision tracker is presented. Furthermore investigations of a precise CNGS beam localization with the precision tracker are performed. After an overview of past and present developments in neutrino physics, the OPERA detector is presented in this thesis. Emphasis is given to the precision tracker which has been partly commissioned in the end of the last year. A first analysis of the functionality with cosmic muons has been performed, as well as the inclusion of data in the OPERA software framework. Within this thesis some useful tools have been developed which are also presented. Finally, divergence effects from the nominal beam line of the CNGS neutrino beam and possible detection with the precision tracker are studied. (orig.)

Membership nominations in international scientific assessments

Science.gov (United States)

Leifeld, Philip; Fisher, Dana R.

2017-10-01

International scientific assessments are transnational knowledge-based expert networks with a mandate to advise policymakers. A well-known example is the Millennium Ecosystem Assessment (MA), which synthesized research on ecosystem services between 2001 and 2005, utilizing the knowledge of 1,360 expert members. Little, however, is known about the membership composition and the driving forces behind membership nominations in the MA and similar organizations. Here we introduce a survey data set on recruitment in the MA and analyse nomination patterns among experts as a complex network. The results indicate that membership recruitment was governed by prior contacts in other transnational elite organizations and a range of other factors related to personal affinity. Network analysis demonstrates how some core individuals were particularly influential in shaping the overall membership composition of the group. These findings add to recently noted concerns about the lack of diversity of views represented in international scientific assessments.

PSR experience with beam losses, instabilities and space charge effects

International Nuclear Information System (INIS)

Macek, R.J.

1998-01-01

Average current from the PSR has been limited to ∼70 μA at 20 Hz by beam losses of 0.4 to 0.5 μA which arise from two principal causes, production of H 0 excited states and stored-beam scattering in the stripper foil. To reduce beam losses, an upgrade from the two-step H 0 injection to direct H - injection is underway and will be completed in 1998. Peak intensity from the PSR is limited by a strong instability that available evidence indicates is the two-stream e-p instability. New evidence for the e-p hypothesis is presented. At operating intensities, the incoherent space charge tune shift depresses both horizontal and vertical tunes past the integer without additional beam loss although some intensity-dependent emittance growth is observed. copyright 1998 American Institute of Physics

Characteristics Leading Teachers to Nominate Secondary Students as Gifted in Spain

Science.gov (United States)

Hernandez-Torrano, Daniel; Prieto, Maria Dolores; Ferrandiz, Carmen; Bermejo, Rosario; Sainz, Marta

2013-01-01

What are the characteristics leading teachers to nominate gifted students in Spain? To answer this question, several demographic (i.e., gender, grade) and psychological (i.e., multiple intelligences, emotional intelligence, intellectual aptitude, and divergent thinking) characteristics of 563 secondary students nominated as gifted by their…

Thermomechanical response of Large Hadron Collider collimators to proton and ion beam impacts

Directory of Open Access Journals (Sweden)

Marija Cauchi

2015-04-01

Full Text Available The CERN Large Hadron Collider (LHC is designed to accelerate and bring into collision high-energy protons as well as heavy ions. Accidents involving direct beam impacts on collimators can happen in both cases. The LHC collimation system is designed to handle the demanding requirements of high-intensity proton beams. Although proton beams have 100 times higher beam power than the nominal LHC lead ion beams, specific problems might arise in case of ion losses due to different particle-collimator interaction mechanisms when compared to protons. This paper investigates and compares direct ion and proton beam impacts on collimators, in particular tertiary collimators (TCTs, made of the tungsten heavy alloy INERMET® 180. Recent measurements of the mechanical behavior of this alloy under static and dynamic loading conditions at different temperatures have been done and used for realistic estimates of the collimator response to beam impact. Using these new measurements, a numerical finite element method (FEM approach is presented in this paper. Sequential fast-transient thermostructural analyses are performed in the elastic-plastic domain in order to evaluate and compare the thermomechanical response of TCTs in case of critical beam load cases involving proton and heavy ion beam impacts.

Measuring linac photon beam energy through EPID image analysis of physically wedged fields

Energy Technology Data Exchange (ETDEWEB)

Dawoud, S. M., E-mail: samir.dawoud@leedsth.nhs.uk; Weston, S. J.; Bond, I.; Ward, G. C.; Rixham, P. A.; Mason, J.; Huckle, A. [Department of Medical Physics and Engineering, St. James Institute of Oncology, St. James University Hospital, Leeds LS9 7TF (United Kingdom); Sykes, J. R. [Institute of Medical Physics, School of Physics, The University of Sydney, New South Wales 2006, Australia and Department of Medical Physics and Engineering, St. James Institute of Oncology, St. James University Hospital, Leeds LS9 7TF (United Kingdom)

2014-02-15

Purpose: Electronic portal imaging devices (EPIDs) have proven to be useful tools for measuring several parameters of interest in linac quality assurance (QA). However, a method for measuring linac photon beam energy using EPIDs has not previously been reported. In this report, such a method is devised and tested, based on fitting a second order polynomial to the profiles of physically wedged beams, where the metric of interest is the second order coefficientα. The relationship between α and the beam quality index [percentage depth dose at 10 cm depth (PDD{sub 10})] is examined to produce a suitable calibration curve between these two parameters. Methods: Measurements were taken in a water-tank for beams with a range of energies representative of the local QA tolerances about the nominal value 6 MV. In each case, the beam quality was found in terms of PDD{sub 10} for 100 × 100 mm{sup 2} square fields. EPID images of 200 × 200 mm{sup 2} wedged fields were then taken for each beam and the wedge profile was fitted in MATLAB 2010b (The MathWorks, Inc., Natick, MA). α was then plotted against PDD{sub 10} and fitted with a linear relation to produce the calibration curve. The uncertainty in α was evaluated by taking five repeat EPID images of the wedged field for a beam of 6 MV nominal energy. The consistency of measuring α was found by taking repeat measurements on a single linac over a three month period. The method was also tested at 10 MV by repeating the water-tank crosscalibration for a range of energies centered approximately about a 10 MV nominal value. Finally, the calibration curve from the test linac and that from a separate clinical machine were compared to test consistency of the method across machines in a matched fleet. Results: The relationship betweenα and PDD{sub 10} was found to be strongly linear (R{sup 2} = 0.979) while the uncertainty in α was found to be negligible compared to that associated with measuring PDD{sub 10} in the water-tank (�

Interfacial intermixing in InAs/GaSb short-period-superlattices grown by molecular beam epitaxy

International Nuclear Information System (INIS)

Luna, E.; Satpati, B.; Trampert, A.; Rodriguez, J. B.; Baranov, A. N.; Tournie, E.

2010-01-01

The unique properties of the noncommon-atom InAs/GaSb short-period-superlattices (SPSL) strongly depend on the interface structure. These interfaces are characterized using transmission electron microscopy (TEM). The compositional sharpness is obtained from the comparison of the experimental contrast in g 002 two-beam dark-field TEM images with simulated intensity profiles, which are calculated assuming that the element distribution profiles are described by sigmoidal functions. The interfacial intermixing, defined by the chemical width, is obtained for SPSL with different periods and layer thicknesses, even in the extreme case of nominally less than 3 ML thick InAs layers. Nominal 1 ML InSb layers intentionally inserted are also identified.

30 CFR 285.706 - How do I nominate a CVA for MMS approval?

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 2 2010-07-01 2010-07-01 false How do I nominate a CVA for MMS approval? 285..., Fabrication, and Installation Certified Verification Agent § 285.706 How do I nominate a CVA for MMS approval... (§ 285.610(a)(9)) or GAP (§ 285.645(c)(5)), you must nominate a CVA for MMS approval. You must specify...

78 FR 68838 - National Drinking Water Advisory Council; Request for Nominations

Science.gov (United States)

2013-11-15

... may nominate qualified individuals for membership. The EPA values and welcomes diversity. In an effort..., position, current business address, and email and telephone number. Interested candidates may self-nominate... ``Ethics Requirements for Advisors'' link on the EPA NDWAC Web site, http://water.epa.gov/drink/ndwac/fact...

78 FR 31939 - Solicitation of Nominations for Membership on the National Vaccine Advisory Committee

Science.gov (United States)

2013-05-28

...., Public Health Advisor, National Vaccine Program Office, Department of Health and Human Services, 200... vacated during the calendar year 2013. Nominations In accordance with the charter, persons nominated for... information should be included in the package of material submitted for each individual being nominated for...

76 FR 71566 - Solicitation of Nominations for Membership on the National Vaccine Advisory Committee

Science.gov (United States)

2011-11-18

...., Public Health Advisor, National Vaccine Program Office, Department of Health and Human Services, 200... vacated during the calendar year 2012. Nominations In accordance with the charter, persons nominated for... information should be included in the package of material submitted for each individual being nominated for...

A Study of the Effect of Preschool Children's Participation in Sensorimotor Activities on Their Understanding of the Mechanical Equilibrium of a Balance Beam

Science.gov (United States)

Hadzigeorgiou, Yannis; Anastasiou, Leonidas; Konsolas, Manos; Prevezanou, Barbara

2009-01-01

The purpose of this study was to investigate whether participation in sensorimotor activities by preschool children involving their own bodily balance while walking on a beam over the floor has an effect on their understanding of the mechanical equilibrium of a balance beam. The balance beam consisted of a horizontal stick balancing around its…

Comment on "Collision monochromatization in e+e- colliders"

Science.gov (United States)

Shatilov, D.

2018-02-01

Bogomyagkov and Levichev [Phys. Rev. Accel. Beams 20, 051001 (2017), 10.1103/PhysRevAccelBeams.20.051001] have recently reported on monochromatization in collision schemes with crossing angle. From their results, in particular, it may seem that: (1) horizontal dispersion at the IP can provide monochromatization factor Λ ≫1 while retaining Piwinski angle ϕ >1 , (2) production rate in such a scheme for FCC-ee at 62.5 GeV can be larger than that in the nominal crab waist collision, and (3) strong rf focusing can be used for monochromatization purposes. We demonstrate here that the first two statements are not correct, and the last one is very doubtful.

Correspondence Analysis of Soil around Micropile Composite Structures under Horizontal Load

Directory of Open Access Journals (Sweden)

Hai Shi

2015-01-01

Full Text Available The current approach, which is based on conformal transformation, is to map micropile holes in comparison with unit circle domain. The stress field of soil around a pile plane, as well as the plane strain solution to displacement field distribution, can be obtained by adopting complex variable functions of elastic mechanics. This paper proposes an approach based on Winkler Foundation Beam Model, with the assumption that the soil around the micropiles stemmed from a series of independent springs. The rigidity coefficient of the springs is to be obtained from the planar solution. Based on the deflection curve differential equation of Euler-Bernoulli beams, one can derive the pile deformation and internal force calculation method of micropile composite structures under horizontal load. In the end, we propose reinforcing highway landslides with micropile composite structure and conducting on-site pile pushing tests. The obtained results from the experiment were then compared with the theoretical approach. It has been indicated through validation analysis that the results obtained from the established theoretical approach display a reasonable degree of accuracy and reliability.

Horizontal Accelerator

Data.gov (United States)

Federal Laboratory Consortium — The Horizontal Accelerator (HA) Facility is a versatile research tool available for use on projects requiring simulation of the crash environment. The HA Facility is...

24 CFR 598.510 - Nominations by Economic Development Corporations or the District of Columbia.

Science.gov (United States)

2010-04-01

... 24 Housing and Urban Development 3 2010-04-01 2010-04-01 false Nominations by Economic Development... ZONES: ROUND TWO AND THREE DESIGNATIONS Special Rules § 598.510 Nominations by Economic Development Corporations or the District of Columbia. Any urban area nominated by an Economic Development Corporation...

77 FR 64113 - National Drinking Water Advisory Council: Request for Nominations

Science.gov (United States)

2012-10-18

... person and/or organization may nominate qualified individuals for membership. The EPA values and welcomes..., current business address, and email and telephone number. Interested candidates may self-nominate. The DFO... Requirements for Advisors'' link on the OGWDW NDWAC Web site, http://water.epa.gov/drink/ndwac/fact.cfm . Other...

Non-linear beam dynamics tests in the LHC: LHC dynamic aperture MD on Beam 2 (24th of June 2012)

CERN Document Server

Maclean, E H; Persson, T H B; Redaelli, S; Schmidt, F; Tomas, R; Uythoven, J

2013-01-01

This MD note summarizes measurements performed on LHC Beam 2 during the non-linear machine development (MD) of 24 June 2012. The aim of the measurement was to observe the dynamic aperture of LHC Beam 2, and obtain turn-by-turn (TbT) betatron oscillation data, enabling the study of amplitude detuning and resonance driving terms (RDTs). The regular injections required by the MD also represented an opportunity to test a new coupling feedback routine based on the analysis of injection oscillation data. Initial measurements were performed on the nominal state of the LHC at injection. On completion of this study the Landau octupoles were turned off and corrections for higher-order chromaticities were implemented to reduce the non-linearity of the machine as far as possible. A second set of measurements were then performed. All studies were performed using the LHC aperture kicker (MKA).

Optical beam diagnostics at the Electron Stretcher Accelerator ELSA

International Nuclear Information System (INIS)

Zander, Sven

2013-10-01

At the ELectron Stretcher Accelerator ELSA, a resonant excitation of the horizontal particle oscillations is used to extract the electrons to the experiments. This so-called resonance extraction influences the properties of the extracted beam. The emittance, as a number of the beam quality, was determined by using synchrotron light monitors. To enable broad investigations of the emittance a system of synchrotron light monitors was set up. This system was used to measure the influence of the extraction method on the emittance. Time resolved measurements were conducted to investigate the development of the emittance during an accelerator cycle. To improve the optical beam diagnostics a new beamline to an external laboratory was constructed. There, a new high resolution synchrotron light monitor was commissioned. In addition, a streak camera has been installed to enable longitudinal diagnostics of the beam profiles. First measurements of the longitudinal charge distribution with a time resolution in the range of a few picoseconds were conducted successfully.

75 FR 61751 - National Drinking Water Advisory Council: Request for Nominations

Science.gov (United States)

2010-10-06

... nominations on or before October 31, 2010. ADDRESSES: The preferred form of communication is via e-mail to...) while attending meetings. The Council holds two face-to-face meetings each year, generally in the spring... Protection Agency (EPA or Agency) invites all interested persons to nominate qualified individuals to serve a...

75 FR 60459 - National Committee on Vital and Health Statistics; Nominations

Science.gov (United States)

2010-09-30

... be made without discrimination on the basis of age, race, gender, sexual orientation, HIV status... nominations is close of business, October 22, 2010. Nominations should be sent to the person named below... anniversary this year, provides advice and assistance to the Department on a variety of key health data issues...

Moral disengagement in self-reported and peer-nominated school bullying

DEFF Research Database (Denmark)

Obermann, Marie-Louise

2011-01-01

. Discrepancies between self-reported and peer-nominated bullying involvement indicates that a person’s social reputation has a stronger association with moral disengagement than so far expected. Implications are discussed, highlighting the importance of further research and theory development.......This study examined the relation between moral disengagement and different self-reported and peer-nominated positions in school bullying. The aims of this study were to (1) investigate moral disengagement among children for whom self-reported and peernominated bully status diverged and (2) compare...... levels of disengagement among self-reported and peer-nominated pure bullies, pure victims, bully–victims, and children not involved in bullying. A sample of 739 Danish sixth grade and seventh grade children (mean age 12.6) was included in the study. Moral disengagement was measured using a Danish version...

Call for petition nominations for 1996-1998 Elections

Science.gov (United States)

The nominees listed below are those of the Union and Section nominating committees and have been approved by the AGU Council.Additional nominations may be made by membership petition. All nominees must be Members or Fellows of the Union. Each petition must be accompanied by a letter in which the proposed nominee agrees to be a candidate and to serve if elected. There are no age, nationality, residence, or other analogous restrictions on who may serve as an officer. Petitions should be sent to the General Secretary, American Geophysical Union, 2000 Florida Avenue NW, Washington, DC 20009. They must be received no later than July 21, 1995.

Adaptation of a ladder beam walking task to assess locomotor recovery in mice following spinal cord injury

Science.gov (United States)

Cummings, Brian J.; Engesser-Cesar, Christie; Anderson, Aileen J.

2007-01-01

Locomotor impairments after spinal cord injury (SCI) are often assessed using open-field rating scales. These tasks have the advantage of spanning the range from complete paralysis to normal walking; however, they lack sensitivity at specific levels of recovery. Additionally, most supplemental assessments were developed in rats, not mice. For example, the horizontal ladder beam has been used to measure recovery in the rat after SCI. This parametric task results in a videotaped archival record of the event, is easily administered, and is unambiguously scored. Although a ladder beam apparatus for mice is available, its use in the assessment of recovery in SCI mice is rare, possibly because normative data for uninjured mice and the type of step misplacements injured mice exhibit is lacking. We report the development of a modified ladder beam instrument and scoring system to measure hindlimb recovery in vertebral T9 contusion spinal cord injured mice. The mouse ladder beam allows for the use of standard parametric statistical tests to assess locomotor recovery. Ladder beam performance is consistent across four strains of mice, there are no sex differences, and inter-rater reliability between observers is high. The ladder beam score is proportional to injury severity and can be used to easily separate mice capable of weight-supported stance up to mice with consistent forelimb to hindlimb coordination. Critically, horizontal ladder beam testing discriminates between mice that score identically in terms of stepping frequency in open-field testing. PMID:17197044

Adaptation of a ladder beam walking task to assess locomotor recovery in mice following spinal cord injury.

Science.gov (United States)

Cummings, Brian J; Engesser-Cesar, Christie; Cadena, Gilbert; Anderson, Aileen J

2007-02-27

Locomotor impairments after spinal cord injury (SCI) are often assessed using open-field rating scales. These tasks have the advantage of spanning the range from complete paralysis to normal walking; however, they lack sensitivity at specific levels of recovery. Additionally, most supplemental assessments were developed in rats, not mice. For example, the horizontal ladder beam has been used to measure recovery in the rat after SCI. This parametric task results in a videotaped archival record of the event, is easily administered, and is unambiguously scored. Although a ladder beam apparatus for mice is available, its use in the assessment of recovery in SCI mice is rare, possibly because normative data for uninjured mice and the type of step misplacements injured mice exhibit is lacking. We report the development of a modified ladder beam instrument and scoring system to measure hindlimb recovery in vertebral T9 contusion spinal cord injured mice. The mouse ladder beam allows for the use of standard parametric statistical tests to assess locomotor recovery. Ladder beam performance is consistent across four strains of mice, there are no sex differences, and inter-rater reliability between observers is high. The ladder beam score is proportional to injury severity and can be used to easily separate mice capable of weight-supported stance up to mice with consistent forelimb to hindlimb coordination. Critically, horizontal ladder beam testing discriminates between mice that score identically in terms of stepping frequency in open-field testing.

Digital transverse beam dampers from the Brookhaven AGS

International Nuclear Information System (INIS)

Smith, G.A.; Castillo, V.; Roser, T.; Van Asselt, W.; Witkover, R.; Wong, V.

1995-01-01

A wide band, digital damper system has been developed and is in use at the Brookhaven Alternating Gradient Synchrotron (AGS). The system consists of vertical and horizontal capacitive pickups, analog and digital processing electronics, four 500 Watt wide band power amplifiers, and two pairs of strip line beam kickers. The system is currently used to damp transverse coherent instabilities and injection errors, in both planes, for protons and all species of heavy ions. This paper discusses the system design and operation, particularly with regard to stabilization of the high intensity proton beam. The analog and digital signal processing techniques used to achieve optimum results are discussed. Operational data showing the effect of the damping are presented

A beam position monitor for the diagnostic line in MEBT2 of J-PARC linac

Science.gov (United States)

Miura, A.; Tamura, J.; Kawane, Y.

2017-07-01

In the linac of the Japan Proton Accelerator Research Complex (J-PARC), the neutral hydrogen (H0) beam from the negative hydrogen ion (H-) beam is one of key issues in mitigating beam losses. To diagnose H0 particles, we installed a set of beam-bump magnets to generate a chicane orbit of the H- beam. The beam position monitors (BPMs) in the beam line are used for orbit correction to maintain the beam displacement within 2.0 mm from the duct center. To measure the beam displacement under different drive currents of the beam-bump magnets, a new wide-range BPM was designed and manufactured to evaluate the horizontal beam position by using a correction function to compensate for non-linearity. We also employed the beam profile monitor (WSM: wire scanner monitor) to measure the H- beam profile, which helped us to compare the beam position measurements. In this paper, the design and the performance of the wide-range BPM are described. In addition, we present a comparison of the beam position measured by the BPM and the WSM.

Radiation dosimetry at the BNL High Flux Beam Reactor

International Nuclear Information System (INIS)

Holden, N.E.; Hu, J.P.; Reciniello, R.N.

1998-02-01

The HFBR is a heavy water, D 2 O, cooled and moderated reactor with twenty-eight fuel elements containing a maximum of 9.8 kilograms of 235 U. The core is 53 cm high and 48 cm in diameter and has an active volume of 97 liters. The HFBR, which was designed to operate at forty mega-watts, 40 NW, was upgraded to operate at 60 NW. Since 1991, it has operated at 30 MW. In a normal 30 MW operating cycle the HFBR operates 24 hours a day for thirty days, with a six to fourteen day shutdown period for refueling and maintenance work. While most reactors attempts to minimize the escape of neutrons from the core, the HFBR's D 2 O design allows the thermal neutron flux to peak in the reflector region and maximizes the number of thermal neutrons available to nine horizontal external beams, H-1 to H-9. The HFBR neutron dosimetry effort described here compares measured and calculated energy dependent neutron and gamma ray flux densities and/or dose rates at horizontal beam lines and vertical irradiation thimbles

Interfacial shear behavior of composite flanged concrete beams

Directory of Open Access Journals (Sweden)

Moataz Awry Mahmoud

2014-08-01

Full Text Available Composite concrete decks are commonly used in the construction of highway bridges due to their rapid constructability. The interfacial shear transfer between the top slab and the supporting beams is of great significance to the overall deck load carrying capacity and performance. Interfacial shear capacity is directly influenced by the distribution and the percentage of shear connectors. Research and design guidelines suggest the use of two different approaches to quantify the required interfacial shear strength, namely based on the maximum compressive forces in the flange at mid span or the maximum shear flow at the supports. This paper investigates the performance of flanged reinforced concrete composite beams with different shear connector’s distribution and reinforcing ratios. The study incorporated both experimental and analytical programs for beams. Key experimental findings suggest that concentrating the connectors at the vicinity of the supports enhances the ductility of the beam. The paper proposes a simple and straight forward approach to estimate the interfacial shear capacity that was proven to give good correlation with the experimental results and selected code provisions. The paper presents a method to predict the horizontal shear force between precast beams and cast in-situ slabs.

Social Anxiety and Sociometric Nomination in Spanish Students of Compulsory Secondary Education.

Science.gov (United States)

Delgado, Beatriz; Inglés, Cándido J; Aparisi, David; García-Fernández, José M

2016-07-18

Adolescents with social anxiety can manifest great interference in their relationship with classmates and other peers, as well as in their school performance. The aim of this study was to analyze the sociometric nominations and assessment of students with high social anxiety by their peers and teachers, and to determine whether these assessments differ significantly between evaluators (peers vs. teachers), in a sample of 2022 (51.1% male) Spanish adolescents aged between 12 and 16 years. Social anxiety was assessed using the Social Phobia and Anxiety Inventory questionnaire. Sociometric identification and assessment of various educational aspects of the students was performed through the Socio program and Teacher assessment scales, respectively. Results show that students with high social anxiety were nominated by peers as popular, rejected and neglected with the same frequency and proportionately less nominated as leaders, friendly, cooperative, and quarrelsome students than those without high social anxiety (d .97). Finally, peers significantly nominated students with high social anxiety more as leaders, cooperative, quarrelsome, obedient and good students than their teachers (d social anxiety are valued and nominated by their peers and teachers differently.

Neutron beam applications

International Nuclear Information System (INIS)

Lee, Chang Hee; Lee, J. S.; Seong, B. S.

2000-05-01

For the materials science by neutron technique, the development of the various complementary neutron beam facilities at horizontal beam port of HANARO and the techniques for measurement and analysis has been performed. High resolution powder diffractometer, after the installation and performance test, has been opened and used actively for crystal structure analysis, magnetic structure analysis, phase transition study, etc., since January 1998. The main components for four circle diffractometer were developed and, after performance test, it has been opened for crystal structure analysis and texture measurement since the end of 1999. For the small angle neutron spectrometer, the main component development and test, beam characterization, and the preliminary experiment for the structure study of polymer have been carried out. Neutron radiography facility, after the precise performance test, has been used for the non-destructive test of industrial component. Addition to the development of main instruments, for the effective utilization of those facilities, the scattering techniques relating to quantitative phase analysis, magnetic structure analysis, texture measurement, residual stress measurement, polymer study, etc, were developed. For the neutron radiography, photographing and printing technique on direct and indirect method was stabilized and the development for the real time image processing technique by neutron TV was carried out. The sample environment facilities for low and high temperature, magnetic field were also developed

Friendship Satisfaction in Children with Autism Spectrum Disorder and Nominated Friends

Science.gov (United States)

Petrina, Neysa; Carter, Mark; Stephenson, Jennifer; Sweller, Naomi

2017-01-01

The current study examined the level of friendship satisfaction of children with autism spectrum disorder (ASD) and their nominated friends (with and without diagnosis of ASD). A total of 77 target children with ASD and friends from 49 nominated friendships participated in the study. Relatively high levels of friendship satisfaction were reported…

Vertical and horizontal test results of 3.9-GHz accelerating cavities at FNAL

Energy Technology Data Exchange (ETDEWEB)

Khabiboulline, T.; Edwards, H.; Foley, M.; Harms, E.; Hocker, James Andrew; Mitchell, D.; Rowe, A.; Solyak, N.; /Fermilab

2008-06-01

The 3rd harmonic 3.9GHz accelerating cavity was proposed to improve the beam performance of the VUV FEL, FLASH. In the frame of a collaborative agreement, Fermilab will provide DESY with a cryomodule containing a string of four cavities. Seven 9-cell Nb cavities were tested and six of them did reach accelerating gradient up to 24 MV/m almost twice more than design value of 14 MV/m. Two of these cavities are with new HOM couplers with improved design. In this paper we present all results of the vertical and horizontal tests.

Transition from slug to annular flow in horizontal air-water flow

International Nuclear Information System (INIS)

Reismann, J.; John, H.; Seeger, W.

1981-11-01

The transition from slug to annular flow in horizontal air-water and steam-water flow was investigated. Test sections of 50; 66.6 and 80 mm ID were used. The system pressure was 0.2 and 0.5 MPa in the air-water experiments and 2.5; 5; 7.5 and 10 MPa in the steam-water experiments. For flow pattern detection local impedance probes were used. This method was compared in a part of the experiments with differential pressure and gamma-beam measurements. The flow regime boundary is shifting strongly to smaller values of the superficial gas velocity with increasing pressure. Correlations from literature fit unsatisfactorily the experimental results. A new correlation is presented. (orig.) [de

Horizontal drilling under Lake Erie

Energy Technology Data Exchange (ETDEWEB)

Meller, R.

2001-07-01

Drilling oil wells under Lake Erie calls for horizontal drilling wells to be drilled from shore out into the pay-zone under the lake. The nature and characteristics of horizontal wells as compared to vertical wells are explored. Considerations that have to be taken into account in drilling horizontal wells are explained (the degree of curvature, drilling fluid quality, geosteering in the pay-zone, steering instrumentation, measurements while drilling (MWD), logging while drilling (LWD)). The concept and reasons for extended reach wells are outlined, along with characteristic features of multilateral wells.

Bending magnets for the CBA beam-transport line

International Nuclear Information System (INIS)

Thern, R.E.

1983-01-01

The beam-transport line from the AGS to CBA requires 68 large bending magnets, consisting of pure dipoles and two types of combined function gradient magnets. All three types were designed with magnetic-field calculation program POISSON, using the same exterior dimensions and coil package. The design goal of +-1% momentum acceptance for the transport line required a wide horizontal aperture, with a much-smaller vertical aperture for economy. Two prototypes of one gradient magnet were built, and a facility constructed to measure them and the later production magnets. Measurements were done using both a long coil and a point coil (Rawson-Lush gaussmeter). Preliminary results show δB/B - 3 , δG/G - 2 , and δB 2 /B - 4 cm - 2 over the beam aperture. Due to end effects, the actual gradient differs from the design gradient by 1%, which has been compensated for in the beam-line design

Narrow linewidth operation of a spectral beam combined diode laser bar.

Science.gov (United States)

Zhu, Zhanda; Jiang, Menghua; Cheng, Siqi; Hui, Yongling; Lei, Hong; Li, Qiang

2016-04-20

Our experiment is expected to provide an approach for realizing ultranarrow linewidth for a spectral beam combined diode laser bar. The beams of a diode laser bar are combined in a fast axis after a beam transformation system. With the help of relay optics and a transform lens with a long focal length of 1.5 m, the whole wavelength of a spectral combined laser bar can be narrowed down to 0.48 nm from more than 10 nm. We have achieved 56.7 W cw from a 19-element single bar with an M2 of 1.4  (in horizontal direction)×11.6  (in vertical direction). These parameters are good evidence that all the beams from the diode laser bar are combined together to increase the brightness.

Planck 2015 results. VII. HFI TOI and beam processing

CERN Document Server

Adam, R.; Aghanim, N.; Arnaud, M.; Ashdown, M.; Aumont, J.; Baccigalupi, C.; Banday, A.J.; Barreiro, R.B.; Bartolo, N.; Battaner, E.; Benabed, K.; Benoît, A.; Benoit-Lévy, A.; Bernard, J.-P.; Bersanelli, M.; Bertincourt, B.; Bielewicz, P.; Bock, J.J.; Bonavera, L.; Bond, J.R.; Borrill, J.; Bouchet, F.R.; Boulanger, F.; Bucher, M.; Burigana, C.; Calabrese, E.; Cardoso, J.-F.; Catalano, A.; Challinor, A.; Chamballu, A.; Chary, R.-R.; Chiang, H.C.; Christensen, P.R.; Clements, D.L.; Colombi, S.; Colombo, L.P.L.; Combet, C.; Couchot, F.; Coulais, A.; Crill, B.P.; Curto, A.; Cuttaia, F.; Danese, L.; Davies, R.D.; Davis, R.J.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Delouis, J.-M.; Désert, F.-X.; Diego, J.M.; Dole, H.; Donzelli, S.; Doré, O.; Douspis, M.; Ducout, A.; Dupac, X.; Efstathiou, G.; Elsner, F.; Enßlin, T.A.; Eriksen, H.K.; Falgarone, E.; Fergusson, J.; Finelli, F.; Forni, O.; Frailis, M.; Fraisse, A.A.; Franceschi, E.; Frejsel, A.; Galeotta, S.; Galli, S.; Ganga, K.; Ghosh, T.; Giard, M.; Giraud-Héraud, Y.; Gjerløw, E.; González-Nuevo, J.; Górski, K.M.; Gratton, S.; Gruppuso, A.; Gudmundsson, J.E.; Hansen, F.K.; Hanson, D.; Harrison, D.L.; Henrot-Versillé, S.; Herranz, D.; Hildebrandt, S.R.; Hivon, E.; Hobson, M.; Holmes, W.A.; Hornstrup, A.; Hovest, W.; Huffenberger, K.M.; Hurier, G.; Jaffe, A.H.; Jaffe, T.R.; Jones, W.C.; Juvela, M.; Keihänen, E.; Keskitalo, R.; Kisner, T.S.; Kneissl, R.; Knoche, J.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lamarre, J.-M.; Lasenby, A.; Lattanzi, M.; Lawrence, C.R.; Le Jeune, M.; Leahy, J.P.; Lellouch, E.; Leonardi, R.; Lesgourgues, J.; Levrier, F.; Liguori, M.; Lilje, P.B.; Linden-Vørnle, M.; López-Caniego, M.; Lubin, P.M.; Macías-Pérez, J.F.; Maggio, G.; Maino, D.; Mandolesi, N.; Mangilli, A.; Maris, M.; Martin, P.G.; Martínez-González, E.; Masi, S.; Matarrese, S.; McGehee, P.; Melchiorri, A.; Mendes, L.; Mennella, A.; Migliaccio, M.; Mitra, S.; Miville-Deschênes, M.-A.; Moneti, A.; Montier, L.; Moreno, R.; Morgante, G.; Mortlock, D.; Moss, A.; Mottet, S.; Munshi, D.; Murphy, J.A.; Naselsky, P.; Nati, F.; Natoli, P.; Netterfield, C.B.; Nørgaard-Nielsen, H.U.; Noviello, F.; Novikov, D.; Novikov, I.; Oxborrow, C.A.; Paci, F.; Pagano, L.; Pajot, F.; Paoletti, D.; Pasian, F.; Patanchon, G.; Pearson, T.J.; Perdereau, O.; Perotto, L.; Perrotta, F.; Pettorino, V.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Pietrobon, D.; Plaszczynski, S.; Pointecouteau, E.; Polenta, G.; Pratt, G.W.; Prézeau, G.; Prunet, S.; Puget, J.-L.; Rachen, J.P.; Reinecke, M.; Remazeilles, M.; Renault, C.; Renzi, A.; Ristorcelli, I.; Rocha, G.; Rosset, C.; Rossetti, M.; Roudier, G.; Rowan-Robinson, M.; Rusholme, B.; Sandri, M.; Santos, D.; Sauvé, A.; Savelainen, M.; Savini, G.; Scott, D.; Seiffert, M.D.; Shellard, E.P.S.; Spencer, L.D.; Stolyarov, V.; Stompor, R.; Sudiwala, R.; Sutton, D.; Suur-Uski, A.-S.; Sygnet, J.-F.; Tauber, J.A.; Terenzi, L.; Toffolatti, L.; Tomasi, M.; Tristram, M.; Tucci, M.; Tuovinen, J.; Valenziano, L.; Valiviita, J.; Van Tent, B.; Vibert, L.; Vielva, P.; Villa, F.; Wade, L.A.; Wandelt, B.D.; Watson, R.; Wehus, I.K.; Yvon, D.; Zacchei, A.

2016-01-01

The Planck High Frequency Instrument (HFI) has observed the full sky at six frequencies (100, 143, 217, 353, 545, and 857 GHz) in intensity and at four frequencies in linear polarization (100, 143, 217, and 353 GHz). In order to obtain sky maps, the time-ordered information (TOI) containing the detector and pointing samples must be processed and the angular response must be assessed. The full mission TOI is included in the Planck 2015 release. This paper describes the HFI TOI and beam processing for the 2015 release. HFI calibration and map-making are described in a companion paper. The main pipeline has been modified since the last release (2013 nominal mission in intensity only), by including a correction for the non-linearity of the warm readout and by improving the model of the bolometer time response. The beam processing is an essential tool that derives the angular response used in all the Planck science papers and we report an improvement in the effective beam window function uncertainty of more than a...

A Fast CVD Diamond Beam Loss Monitor for LHC

CERN Document Server

Griesmayer, E; Dobos, D; Effinger, E; Pernegger, H

2011-01-01

Chemical Vapour Deposition (CVD) diamond detectors were installed in the collimation area of the CERN LHC to study their feasibility as Fast Beam Loss Monitors in a high-radiation environment. The detectors were configured with a fast, radiation-hard pre-amplifier with a bandwidth of 2 GHz. The readout was via an oscilloscope with a bandwidth of 1 GHz and a sampling rate of 5 GSPS. Despite the 250 m cable run from the detectors to the oscilloscope, single MIPs were resolved with a 2 ns rise time, a pulse width of 10 ns and a time resolution of less than 1 ns. Two modes of operation were applied. For the analysis of unexpected beam aborts, the loss profile was recorded in a 1 ms buffer and, for nominal operation, the histogram of the time structure of the losses was recorded in synchronism with the LHC period of 89.2 μs. Measurements during the LHC start-up (February to December 2010) are presented. The Diamond Monitors gave an unprecedented insight into the time structure of the beam losses resolving the 400...

A new crossed molecular beam apparatus using time-sliced ion velocity imaging technique

International Nuclear Information System (INIS)

Wu Guorong; Zhang Weiqing; Pan Huilin; Shuai Quan; Jiang Bo; Dai Dongxu; Yang Xueming

2008-01-01

A new crossed molecular beam apparatus has been constructed for investigating polyatomic chemical reactions using the time-sliced ion velocity map imaging technique. A unique design is adopted for one of the two beam sources and allows us to set up the molecular beam source either horizontally or vertically. This can be conveniently used to produce versatile atomic or radical beams from photodissociation and as well as electric discharge. Intensive H-atom beam source with high speed ratio was produced by photodissociation of the HI molecule and was reacted with the CD 4 molecule. Vibrational-state resolved HD product distribution was measured by detecting the CD 3 product. Preliminary results were also reported on the F+SiH 4 reaction using the discharged F atom beam. These results demonstrate that this new instrument is a powerful tool for investigating chemical dynamics of polyatomic reactions.

Electron Cloud Observations during LHC Operation with 25 ns Beams

CERN Document Server

Li, Kevin; Iadarola, Giovanni; Mether, Lotta; Romano, Annalisa; Rumolo, Giovanni; Schenk, Michael

2016-01-01

While during the Run 1 (2010-2012) of the Large Hadron Collider (LHC) most of the integrated luminosity was produced with 50 ns bunch spacing, for the Run 2 start-up (2015) it was decided to move to the nominal bunch spacing of 25 ns. As expected, with this beam configuration strong electron cloud effects were observed in the machine, which had to be mitigated with dedicated 'scrubbing' periods at injection energy. This enabled to start the operation with 25 ns beams at 6.5 TeV, but e-cloud effects continued to pose challenges while gradually increasing the number of circulating bunch trains. This contribution will review the encountered limitations and the mitigation measures that where put in place and will discuss possible strategies for further performance gain.

Formal solution for the fields within a beam-bug calibrator

International Nuclear Information System (INIS)

Fessenden, T J.

1998-01-01

For some time I was bothered by the fact that measurements of offsets in the various bug calibration setups never agreed with the simple formulae (2) used for determining electron beam position in the Livermore induction linacs and transport systems. About 1983 I realized that the discrepancy arises from the way the bug calibrator simulates an electron beam in a conducting pipe. At that time I solved the problem using the method presented here. Unfortunately, I did not write it up at that time. After considerable effort, I was able to repeat the calculation. Since I have little confidence that after a few years I could ever do it again, I felt obliged to write it up in some detail. Our beam bug calibrator consists of two conducting cylinders, nominally concentric, that simulate the electron beam within a drift tube. The radii of the larger cylinder is 2.3 times that of the smaller giving an electrical impedance of 50 Ohms to the coaxial combination. To simulate a beam off-axis within a drift tube, the inner tube is moved relative to the outer tube. This only approximately simulates the motion of a beam because the surface current on the inner tube redistributes in response to the translation. Fortunately, the fields of the translated inner cylinder can be found exactly using complex variable theory (1)

Beam position measurement in transport line-1 of Indus accelerator

International Nuclear Information System (INIS)

Ojha, Avanish; Yadav, Surendra; Holikatti, Anil C.; Puntambekar, T.A.; Pithawa, C.K.

2011-01-01

In Indus Accelerator Complex at RRCAT Indore, 20 MeV electron beam is transported from injector Microtron to Booster Synchrotron through Transport Line-1 (TL-1). This beam has nominal pulse width of 500 ns with repetition rate of 1 Hz. A split electrode type beam position Indicator (BPI) is planned to be used to detect position of beam in TL-1, for which a four-channel processing electronics has been designed and developed. The circuit consists of microcontroller based four-channel peak detector circuit followed by multiplexer and ADC. The microcontroller is triggered from the timing system of microtron, which enables microcontroller to control and synchronize various parts of electronics. Microcontroller also sends the digitized data to a PC on serial link. During development, a problem of overcharging of capacitor was faced, which was resulting in false peak detection. Circuit was simulated and necessary modifications were incorporated in the circuit to solve this problem. A test setup with provision to simulate the beam signal using an antenna was used for testing the circuit in lab and a suitable Graphical User Interface (GUI) program was developed in LabVIEW. This GUI can also be used to calibrate the BPI. The prototype BPI was tested under simulated beam condition, which gave positional accuracy of ± 200 microns. (author)

Evaluation of an aSi-EPID with flattening filter free beams: Applicability to the GLAaS algorithm for portal dosimetry and first experience for pretreatment QA of RapidArc

International Nuclear Information System (INIS)

Nicolini, G.; Clivio, A.; Vanetti, E.; Cozzi, L.; Fogliata, A.; Krauss, H.; Fenoglietto, P.

2013-01-01

Purpose: To demonstrate the feasibility of portal dosimetry with an amorphous silicon mega voltage imager for flattening filter free (FFF) photon beams by means of the GLAaS methodology and to validate it for pretreatment quality assurance of volumetric modulated arc therapy (RapidArc).Methods: The GLAaS algorithm, developed for flattened beams, was applied to FFF beams of nominal energy of 6 and 10 MV generated by a Varian TrueBeam (TB). The amorphous silicon electronic portal imager [named mega voltage imager (MVI) on TB] was used to generate integrated images that were converted into matrices of absorbed dose to water. To enable GLAaS use under the increased dose-per-pulse and dose-rate conditions of the FFF beams, new operational source-detector-distance (SDD) was identified to solve detector saturation issues. Empirical corrections were defined to account for the shape of the profiles of the FFF beams to expand the original methodology of beam profile and arm backscattering correction. GLAaS for FFF beams was validated on pretreatment verification of RapidArc plans for three different TB linacs. In addition, the first pretreatment results from clinical experience on 74 arcs were reported in terms of γ analysis.Results: MVI saturates at 100 cm SDD for FFF beams but this can be avoided if images are acquired at 150 cm for all nominal dose rates of FFF beams. Rotational stability of the gantry-imager system was tested and resulted in a minimal apparent imager displacement during rotation of 0.2 ± 0.2 mm at SDD = 150 cm. The accuracy of this approach was tested with three different Varian TrueBeam linacs from different institutes. Data were stratified per energy and machine and showed no dependence with beam quality and MLC model. The results from clinical pretreatment quality assurance, provided a gamma agreement index (GAI) in the field area for six and ten FFF beams of (99.8 ± 0.3)% and (99.5 ± 0.6)% with distance to agreement and dose difference criteria

Three decision-making aids: brainstorming, nominal group, and Delphi technique.

Science.gov (United States)

McMurray, A R

1994-01-01

The methods of brainstorming, Nominal Group Technique, and the Delphi technique can be important resources for nursing staff development educators who wish to expand their decision-making skills. Staff development educators may find opportunities to use these methods for such tasks as developing courses, setting departmental goals, and forecasting trends for planning purposes. Brainstorming, Nominal Group Technique, and the Delphi technique provide a structured format that helps increase the quantity and quality of participant responses.

CoPt nanoparticles deposited by electron beam evaporation

International Nuclear Information System (INIS)

Castaldi, L.; Giannakopoulos, K.; Travlos, A.; Niarchos, D.; Boukari, S.; Beaurepaire, E.

2005-01-01

Co 50 Pt 50 nanoparticles were co-deposited on thermally oxidized Si substrates by electron beam evaporation at 750 deg C. The mean particle sizes are between ∼5 and ∼20 nm and depend on the nominal thickness of the layer. Different processing conditions resulted in different structural and morphological properties of the samples which led to superparamagnetic and ferromagnetic behaviors. The post-annealing treatment of the CoPt nanograins resulted in the crystallization of the L1 0 ordered phase and in the magnetic hardening of nanoparticles with a maximum coercivity of ∼7.4 kOe

Radiation protection clothing in X-ray diagnostics. Comparison of attenuation equivalents in narrow beam and inverse broad-beam geometry

International Nuclear Information System (INIS)

Pichler, Thomas; Schoepf, T.; Ennemoser, O.

2011-01-01

Purpose: Standard DIN EN 61 331-1 for attenuation measurements in the narrow and broad beam as well as DIN 6857-1 for the determination of shielding properties in the inverse broad-beam geometry are available for testing the attenuation of protection clothing. The attenuation measurements in the narrow beam don't consider scattered radiation and fluorescence due to the arrangement. This leads to the fact that the protective effect of lead-free materials will be misestimated when compared to lead. Therefore, the differences in attenuation equivalents, determined by both test methods for topical radiation protection aprons, were examined. Materials and Methods: The attenuations in inverse broad-beam geometry according to DIN 6857-1 and in the narrow beam according to DIN EN 61 331-1 were measured using commercially available aprons. They were made of lead, lead-reduced and lead-free materials. For determination of the attenuation equivalents, certificated lead-foils with high purity and a precise thickness of 0.1 to 1.25 mm were used. Results: The measurements in the narrow beam according to DIN EN 61 331-1 showed that nearly all aprons reach the required lead equivalent at mid-range tube voltages of 100 kV. At higher and lower tube voltages, the requirements of DIN EN 61 331-3 were largely not met. In contrast, the testing of the same aprons in inverse broad-beam geometry according to DIN 6857-1 showed that only a few aprons meet the requirements for being classified in the nominal protection class. Conclusion: The measurements suggest that testing method DIN 6857-1 has yet to prevail and that manufacturers are just beginning to develop the appropriate protective materials. (orig.)

Penetrating particles in horizontal air showers

International Nuclear Information System (INIS)

Wohlenberg, J.; Boehm, E.

1975-01-01

Particle density and arrival time of muons has been measured in Horizontal Air Showers. 5,600 showers have been recorded in 7,800 hours. Using stringent selection criteria 155 showers have been found horizontal (zenith angle larger 70 0 ) in the size range 4.1 > lg N > 5.5. The muons observed in these showers can be explained by purely electromagnetic origin of horizontal showers. (orig.) [de

SELECTION OF RATIONAL PARAMETERS OF THE NOMINAL MODE OF ELECTRIC LOCOMOTIVES

Directory of Open Access Journals (Sweden)

H. K. Hetman

2017-02-01

Full Text Available Purpose.The railways of Ukraine have been operated the locomotives, which are both morally and physically obsolete. Therefore, to ensure the competitiveness of rail transport it is necessary to update the locomotive fleet, and first of all the fleet of electric locomotives, because electrified railways provide the greater part of passenger and freight traffic. In this connection it is of special importance to determine the optimum parameters of the nominal mode of electric rolling stock. The purpose of the work is to examine the features of solution of these problems with respect to electric locomotives. Methodology. Assuming that the limit values of traction force are determined by the conditions of wheel-rail grip, then the power of the nominal mode can be represented as the product of rated speed, estimated friction coefficient, train weight and the coefficients that represent the ratio of the estimated (starting value of traction force to value of traction force the nominal mode and the ratio of the mass of the locomotive to the train weight. Since the mass of the train is not a constant value, there is always a surplus power of the locomotive fleet required for the mastering of a predetermined volume of transportations. Reduced overcapacity of the locomotive fleet can be achieved by introduction of the locomotives of different power, designed for driving trains of different weight that will result in increased completeness of the power use but also in difficulty in selecting of locomotives for trains in operation. The paper shows the method of calculating the optimum values of power, speed and traction force of the nominal mode. It presents the mathematical model of the relationship of traction rate, excessive capacity and power of the traction unit. Findings.It is proved that the power of the traction unit, the total fleet power requirement and the excess of power in absolute units are proportional to the speed of the nominal mode. To

36 CFR 60.11 - Requests for nominations.

Science.gov (United States)

2010-07-01

... Officer need not process the nomination, unless so requested by the Keeper pursuant to § 60.12. (d) The... also provide notice to the applicant of the time and place of the Review Board meeting at least 30 but...

Observation of helium flow induced beam orbit oscillations at RHIC

International Nuclear Information System (INIS)

Montag, C.; Bonati, R.; Brennan, J.M.; Butler, J.; Cameron, P.; Ganetis, G.; He, P.; Hirzel, W.; Jia, L.X.; Koello, P.; Louie, W.; McIntyre, G.; Nicoletti, A.; Rank, J.; Roser, T.; Satogata, T.; Schmalzle, J.; Sidi-Yekhlef, A.; Sondericker, J.; Tallerico, T.

2006-01-01

Horizontal beam orbit jitter at frequencies around 10 Hz has been observed at RHIC for several years. The distinct frequencies of this jitter have been found at superconducting low-beta quadrupole triplet magnets around the ring, where they coincide with mechanical vibration modes of the cold masses. Recently, we have identified liquid helium flow as the driving force of these oscillations

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

International Nuclear Information System (INIS)

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

2016-01-01

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

OPERATIONAL EXPERIENCE WITH BEAM ABORT SYSTEM FOR SUPERCONDUCTING UNDULATOR QUENCH MITIGATION*

Energy Technology Data Exchange (ETDEWEB)

Harkay, Katherine C.; Dooling, Jeffrey C.; Sajaev, Vadim; Wang, Ju

2017-06-25

A beam abort system has been implemented in the Advanced Photon Source storage ring. The abort system works in tandem with the existing machine protection system (MPS), and its purpose is to control the beam loss location and, thereby, minimize beam loss-induced quenches at the two superconducting undulators (SCUs). The abort system consists of a dedicated horizontal kicker designed to kick out all the bunches in a few turns after being triggered by MPS. The abort system concept was developed on the basis of single- and multi-particle tracking simulations using elegant and bench measurements of the kicker pulse. Performance of the abort system—kick amplitudes and loss distributions of all bunches—was analyzed using beam position monitor (BPM) turn histories, and agrees reasonably well with the model. Beam loss locations indicated by the BPMs are consistent with the fast fiber-optic beam loss monitor (BLM) diagnostics described elsewhere [1,2]. Operational experience with the abort system, various issues that were encountered, limitations of the system, and quench statistics are described.

ATLAS Barrel Toroid magnet reached nominal field

CERN Multimedia

2006-01-01

 On 9 November the barrel toroid magnet reached its nominal field of 4 teslas, with an electrical current of 21 000 amperes (21 kA) passing through the eight superconducting coils as shown on this graph

Intense heavy-ion beam transport with electric and magnetic quadrupoles

International Nuclear Information System (INIS)

Fessenden, T.J.; Hopkins, H.S.

1995-08-01

As part of the small induction recirculator development at LLNL, the authors are testing an injector and transport line that delivers 4 micros beams of potassium with repetition rates up to 10 Hz at a nominal current of 2 mA. The normalized K-V equivalent emittance of the beams is near 0.02 π mm-mrad and is mostly determined by the temperature of the source (0.1 eV). K + ions generated at 80 keV in a Pierce diode are matched to an alternating gradient transport line by seven electric quadrupoles. Two additional quads have been modified to serve as two-axis steerers. The matching section is followed by a transport section comprised of seven permanent magnet quadrupoles. Matching to this section is achieved by adjusting the voltages on the electric quadrupoles to voltages calculated by an envelope matching code. Measurements of beam envelope parameters are made at the matching section entrance and exit as well as at the end of the permanent magnet transport section. Beam current waveforms along the experiment are compared with results from a one-dimension longitudinal dynamics code. Initial experiments show particle loss occurring at the beam head as a result of overtaking. The apparatus is also being used for the development of non or minimally intercepting diagnostics for future recirculator experiments. These include capacitive monitors for determining beam line-charge density and position in the recirculator; flying wire scanners for beam position; and gated TV scanners for measuring beam profiles and emittance

Horizontal violence in Nursing

Directory of Open Access Journals (Sweden)

Tsimoulaki Evangelia

2017-01-01

Full Text Available One’s effort to clarify the definition of horizontal labour violence is of great importance, due to the variety of definitions that are mentioned in the worldwide scientific literature. Furthermore, the reference of multiple forms of such violence herein the nurse professional group is challenging, as well. Another fact of great importance is that, any form of professional violence (horizontal violence, horizontal mobbing in the work place environment can be possibly escalated and include even physical abuse (Bullying, besides the psychological and emotional impact for the victim. The definitions of Horizontal violence, Mobbing and Bullying, include a repeated negative behaviour emanating from at least one “predator” towards at least one “victim”, with work status differences and the existence or lack of physical abuse (Bullying. Horizontal violence is a hostile, aggressive and harmful behaviour which is either overt or concealed and is pointed from an individual to another individual of the same working rank and causes intense emotional pain at the victim. The manifestations vary from humiliating tasks assignment or the victim’s efforts undermining to clearly aggressive behaviors (criticism, intimidation, sarcasm etc.. The reason behind this phenomenon is multifactorial extended not only towards the working environment but also to the personal characteristics of the “predator” as well as the possible “victim”. The researchers emphasize the high incidence of the phenomenon, as well as the cost that is induced by the violent behaviors to both the health professionals and the hospital. Finally, they point out the paradox of the presence of violence inside a system that is designed to promote health.

Stochastic Nominal Wage Contacts in a Cash-in-Advance Model

OpenAIRE

Collard, Fabrice; Ertz, Guy

1996-01-01

We build a simple cash-in-advance model for the German economy, in which we introduce stochastic nominal wage contracts. This allows to weaken the negative effect of the inflation tax such that monetary shocks exert a positive effect on output dynamics. The nominal wage contract model is able to mimic the correlation of inflation and real balances with output. It also lowers the standard deviation of inflation relative to that of output. Further, the variance decomposition analysis indicates ...

Precision analog signal processor for beam position measurements in electron storage rings

International Nuclear Information System (INIS)

Hinkson, J.A.; Unser, K.B.

1995-05-01

Beam position monitors (BPM) in electron and positron storage rings have evolved from simple systems composed of beam pickups, coaxial cables, multiplexing relays, and a single receiver (usually a analyzer) into very complex and costly systems of multiple receivers and processors. The older may have taken minutes to measure the circulating beam closed orbit. Today instrumentation designers are required to provide high-speed measurements of the beam orbit, often at the ring revolution frequency. In addition the instruments must have very high accuracy and resolution. A BPM has been developed for the Advanced Light Source (ALS) in Berkeley which features high resolution and relatively low cost. The instrument has a single purpose; to measure position of a stable stored beam. Because the pickup signals are multiplexed into a single receiver, and due to its narrow bandwidth, the receiver is not intended for single-turn studies. The receiver delivers normalized measurements of X and Y position entirely by analog means at nominally 1 V/mm. No computers are involved. No software is required. Bergoz, a French company specializing in precision beam instrumentation, integrated the ALS design m their new BPM analog signal processor module. Performance comparisons were made on the ALS. In this paper we report on the architecture and performance of the ALS prototype BPM

Diffraction and depths-of-field effects in electron beam imaging at SURF III

International Nuclear Information System (INIS)

Arp, U.

2001-01-01

Imaging an electron beam with visible light is a common method of diagnostics applied to electron accelerators. It is a straightforward way to deduce the transverse electron distribution as well as its changes over time. The electrons stored in the Synchrotron Ultraviolet Radiation Facility (SURF) III at the National Institute of Standards and Technology (NIST) were studied over an extended period of time to characterize the upgraded accelerator. There is good agreement between experimental and theoretical horizontal beam sizes at three different electron energies

Horizontal steam generator thermal-hydraulics

Energy Technology Data Exchange (ETDEWEB)

Ubra, O. [SKODA Praha Company, Prague (Czechoslovakia); Doubek, M. [Czech Technical Univ., Prague (Czechoslovakia)

1995-09-01

Horizontal steam generators are typical components of nuclear power plants with pressure water reactor type VVER. Thermal-hydraulic behavior of horizontal steam generators is very different from the vertical U-tube steam generator, which has been extensively studied for several years. To contribute to the understanding of the horizontal steam generator thermal-hydraulics a computer program for 3-D steady state analysis of the PGV-1000 steam generator has been developed. By means of this computer program, a detailed thermal-hydraulic and thermodynamic study of the horizontal steam generator PGV-1000 has been carried out and a set of important steam generator characteristics has been obtained. The 3-D distribution of the void fraction and 3-D level profile as functions of load and secondary side pressure have been investigated and secondary side volumes and masses as functions of load and pressure have been evaluated. Some of the interesting results of calculations are presented in the paper.

Normal Conducting Separation Dipoles for the LHC Beam Cleaning Insertions

CERN Document Server

Bidon, S; Hans, O; Kalbreier, Willi; Kiselev, O; Petrov, V; Protopopov, I V; Pupkov, Yu A; Ramberger, S; de Rijk, G; Ruvinsky, E; Sukhanov, A

2004-01-01

In the Large Hadron Collider (LHC), two straight sections, IR3 and IR7, will be dedicated to beam cleaning. These cleaning insertions will be equipped with normal conducting magnets. MBW magnets are dipole magnets used to increase the separation of the two beams. They have a core length of 3.4 m and a gap height of 52 mm and will operate at a magnetic field ranging from 0.09 T to 1.53 T. Limitations on the dimensions and total weight of the magnet resulted in a special design with a common yoke for the two beams. The orbits of the two beams will be separated horizontally by a distance between 194 mm and 224 mm in the gap of the magnet. The magnet was designed in collaboration between CERN and BINP. The report presents the main design issues and results of the pre-series acceptance tests including mechanical, electrical and magnetic field measurements.

Flow condensation pressure drop characteristics of R410A-oil mixture inside small diameter horizontal microfin tubes

Energy Technology Data Exchange (ETDEWEB)

Huang, Xiangchao; Ding, Guoliang; Hu, Haitao; Zhu, Yu [Institute of Refrigeration and Cryogenics, Shanghai Jiaotong University, Shanghai 200240 (China); Gao, Yifeng [International Copper Association Shanghai Office, Shanghai 200020 (China); Deng, Bin [Institute of Heat Transfer Technology, Golden Dragon Precise Copper Tube Group Inc., Shanghai 200135 (China)

2010-11-15

Flow condensation pressure drop characteristics of R410A-oil mixture inside small diameter (5.0 mm and 4.0 mm O.D.) horizontal microfin tubes were investigated experimentally covering nominal oil concentrations from 0% to 5%. The research results indicate that, comparing with the frictional pressure drop of pure R410A, the frictional pressure drop of R410A-oil mixture may decrease by maximum of 18% when the vapor quality is lower than 0.6, and increase by maximum of 13% when the vapor quality is higher than 0.6. A new frictional pressure drop correlation for R410A-oil mixture flow condensation inside microfin tubes is developed based on the refrigerant-oil mixture properties, and can agree with 94% of the experimental data within a deviation of -30% to +30%. (author)

Study of the Local Horizon. (Spanish Title: Estudio del Horizonte Local.) Estudo do Horizonte Local

Science.gov (United States)

Ros, Rosa M.

2009-12-01

The study of the horizon is fundamental to easy the first observations of the students at any education center. A simple model, to be developed in each center, allows to easy the study and comprehension of the rudiments of astronomy. The constructed model is presented in turn as a simple equatorial clock, other models (horizontal and vertical) may be constructed starting from it. El estudio del horizonte es fundamental para poder facilitar las primeras observaciones de los alumnos en un centro educativo. Un simple modelo, que debe realizarse para cada centro, nos permite facilitar el estudio y la comprensión de los primeros rudimentos astronómicos. El modelo construido se presenta a su vez como un sencillo modelo de reloj ecuatorial y a partir de él se pueden construir otros modelos (horizontal y vertical). O estudo do horizonte é fundamental para facilitar as primeiras observações dos alunos num centro educativo. Um modelo simples, que deve ser feito para cada centro, permite facilitar o estudo e a compreensão dos primeiros rudimentos astronômicos. O modelo construído apresenta-se, por sua vez, como um modelo simples de relógio equatorial e a partir dele pode-se construir outros modelos (horizontal e vertical)

75 FR 43933 - Request for nominations for members to serve on National Institute of Standards and Technology...

Science.gov (United States)

2010-07-27

... duties. Selection of ISPAB members will not be limited to individuals who are nominated. Nominations that.... Selection of MEP Advisory Board members will not be limited to individuals who are nominated. Nominations... in its official role as the private sector policy advisor of the Institute is concerned. Each such...

77 FR 40332 - Request for Nominations for Members To Serve on National Institute of Standards and Technology...

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2012-07-09

... duties. Selection of ISPAB members will not be limited to individuals who are nominated. Nominations that... to individuals who are nominated. Nominations that are received and meet the requirements will be... policy advisor of NIST is concerned. Each such report shall identify areas of program emphasis for NIST...

78 FR 67121 - Request for Nominations for Members To Serve on National Institute of Standards and Technology...

Science.gov (United States)

2013-11-08

... to individuals who are nominated. Nominations that are received and meet the requirements will be.... Selection of MEP Advisory Board members will not be limited to individuals who are nominated. Nominations... official role as the private sector policy adviser of NIST is concerned. Each such report shall identify...

Assessment of CaSO4:Dy and LiF:Mg,Ti thermoluminescent dosimeters performance in the dosimetry of clinical electron beams

International Nuclear Information System (INIS)

Nunes, Maira Goes

2008-01-01

The assessment of the performance of CaS0 4 :Dy thermoluminescent detectors produced by IPEN in the dosimetry of clinical electron beams aims to propose an alternative to the LiF:Mg,Ti commercial dosimeters (TLD-100) largely applied in radiation therapy. The two types of thermoluminescent dosimeters were characterised with the use of PMMA, RMI-457 type solid water and water phantoms in radiation fields of 4, 6, 9, 12 and 16 MeV electrons of nominal energies in which the dose-response curves were obtained and the surface and depth doses were determined. The thermoluminescent response dependency with the electron nominal energies and the applied phantom were studied. The CaS0 4 :Dy presented the same behaviour than the LiF:Mg,Ti in such a way that its application as an alternative to the TLD-100 pellets in the radiation therapy dosimetry of electron beams is viable and presents the significantly higher sensitivity to the electron radiation as its main advantage. (author)

Beam position pickup for antiprotons to the ISR

CERN Multimedia

CERN PhotoLab

1981-01-01

The Antiproton Project, launched for proton-antiproton collisions in the SPS (SPS collider), had a side-line for p-pbar collisions in the ISR. A new transfer line, TT6, was constructed to transport antiprotons from the 26 GeV PS to the injection line TT1 of ISR ring 2. Antiprotons were a scarce commodity. For setting up the lines, beam diagnostic devices in the antiproton path had to work reliably and precisely with just a few low-intensity pilot pules: single bunches of about 2x10**9 antiprotons every few hours. Electrostatic pickup electrodes were used to measure beam position. They could be mounted for measurement in the horizontal plane, as in this picture, or at 90 deg, for the vertical plane.

Beam dynamics in a TeV linear collider

International Nuclear Information System (INIS)

Yokoya, Kaoru

1984-01-01

The author's group at KEK has investigated the feasibility of an electron-positron linear collider of 1x1 TeV region using the Lasertron. In this report, three major problems are discussed. That is, beam-beam interaction; beam instability in the linac; and the damping ring. As the most important parameter, the luminosity of the linear collider is analyzed, taking into account the pinch effect and the beamstrahlung. The problems in the development of final focusing system are also considered. As for the wake field in the linac, the transverse wake field is more important than the longitudinal one. The misalignment of cavity is discussed as a cause of inducing the transverse wake field. Finally, the design requirement for the damping ring is considered, and the values of some important design parameters are given: These include energy, radius, bending radius, number of bunch, transverse damping time, natural emittance, vertical-horizontal coupling, the time constant of extraction kicker, and the structure of the FODO cell. (Aoki, K.)

76 FR 39379 - Request for Nominations for Members To Serve on National Institute of Standards and Technology...

Science.gov (United States)

2011-07-06

... will not be limited to individuals who are nominated. Nominations that are received and meet the... individuals who are nominated. Nominations that are received and meet the requirements will be kept on file to... in its official role as the private sector policy advisor of the Institute is concerned. Each such...

An Influence of 7.5 T Superconducting Wiggler on Beam Parameters of Siberia-2 Storage Ring

International Nuclear Information System (INIS)

Korchuganov, Vladimir; Valentinov, Alexander; Mezentsev, Nikolai

2007-01-01

At present the dedicated synchrotron radiation source Siberia-2 in Kurchatov Institute operates with electron energy 2.5 GeV and current up to 200 mA. In order to expand spectral range of SR and to increase brightness an installation of 7.5 T 19-pole superconducting wiggler is planned at the end of 2006. Now the wiggler is under fabrication in BINP, Novosibirsk. Such high level of a magnetic field in the wiggler will have a great influence on electron beam parameters of Siberia-2. Changes of these parameters (betatron tunes, horizontal emittance of the electron beam, momentum compaction, energy spread etc.) are discussed in the report. Different methods of compensation (global and local) of betatron functions distortion are presented. Much attention is paid to dynamic aperture calculations using analytical approximation of magnetic field behavior in transverse horizontal direction

Modulation Transfer Function of a Gaussian Beam Based on the Generalized Modified Atmospheric Spectrum

Directory of Open Access Journals (Sweden)

Chao Gao

2016-01-01

Full Text Available This paper investigates the modulation transfer function of a Gaussian beam propagating through a horizontal path in weak-fluctuation non-Kolmogorov turbulence. Mathematical expressions are obtained based on the generalized modified atmospheric spectrum, which includes the spectral power law value of non-Kolmogorov turbulence, the finite inner and outer scales of turbulence, and other optical parameters of the Gaussian beam. The numerical results indicate that the atmospheric turbulence would produce less negative effects on the wireless optical communication system with an increase in the inner scale of turbulence. Additionally, the increased outer scale of turbulence makes a Gaussian beam influenced more seriously by the atmospheric turbulence.

Beam emittance of the Stony Brook Tandem-LINAC booster

International Nuclear Information System (INIS)

Scholldorf, A.H.

1984-01-01

This dissertation is primarily a study of the longitudinal and transverse beam emittance of the Stony Brook Heavy Ion Tandem LINAC Accelerator Facility, with a secondary emphasis on the beam dynamical design of two key elements of the system: a low energy double-drift buncher, and an achromatic double-90 0 LINAC injection system. A transverse emittance measuring system consisting of two translation stages controlled by stepper motors is described. Each stage carried a pair of beam defining slits mounted so that both horizontal and vertical emittances could be measured with only linear motion of the stage assembly. Beam currents were measured directly by a low-noise, high-sensitivity electrometer circuit integrated with the second slit-stage assembly. A mini-computer controlled the motors and acquired and displayed the data. Transverse emittance areas of beams of 12 C, 16 O, 32 S, and 58 Ni were measured at ion source extraction potential, after ion source acceleration, after tandem acceleration, and after LINAC acceleration. The results were analyzed in terms of source sputter-cone geometry, angle straggling in gas and foil strippers, and a variety of other factors

Long-term deflection and flexural behavior of reinforced concrete beams with recycled aggregate

International Nuclear Information System (INIS)

Choi, Won-Chang; Yun, Hyun-Do

2013-01-01

Highlights: • Long-term deformation of recycled aggregate concrete beams was examined. • Three beams were monitored for over 380 days. • Influence of recycled aggregate on the long-term performance. • Comparison of that between normal and recycled aggregate concrete beams. - Abstract: This paper presents experimental results on the long-term deformations of recycled aggregate concrete (RAC) beams for over 1 year (380 days) and flexural behavior of RAC beams after exposure to sustained loading. Three reinforced concrete (RC) beam specimens were fabricated with replacement percentage of aggregate (100% natural aggregate, 100% recycled coarse aggregate, and 50% recycled fine aggregate) and subjected to sustained loading that is 50% of the nominal flexural capacity. During the sustained loading period (380 days), the long-term deflection due to creep and shrinkage was recorded and compared with predicted behavior that was determined based on current specifications (ACI 318 Code). After measuring the long-term deflection for 380 days, four-point bending tests were conducted to investigate the flexural behavior of RC beams after exposure to sustained loading and determine any reduction in flexural capacity. A modified equation to predict the long-term deflection values for RC beams with recycled aggregate is proposed, and the experimental results are compared with the predictions calculated using the ACI 318 Code provisions

Blade-type X-ray beam position monitors for SPring-8 undulator beamlines

CERN Document Server

Aoyagi, H; Kitamura, H

2001-01-01

The X-ray beam position monitors had been designed and installed for SPring-8 insertion device beamlines. These monitors are being utilized for photon beam diagnostics. The beam from the standard undulator in SPring-8 has the total power of 11 kW and the power density of 470 kW/mrad sup 2 , typically. Each monitor has four CVD diamond blades coated with metal for detector heads. We have already introduced three styles of monitors to match various insertion devices in SPring-8. A standard style, or a fixed-blade style, is used mainly for a standard in-vacuum undulator beamlines. A horizontal-blade-drive style and a four-blade-drive style are used for beamlines of a wiggler and a twin helical undulator that have wide power distributions, and for figure-8 undulators that have asymmetric power distributions, respectively. This report describes the design and the structure of these monitors and the beam-tests for the photon beam diagnostics in detail.

Nominal Anchors in the CIS

OpenAIRE

Peter M Keller; Thomas J Richardson

2003-01-01

Monetary policy has become increasingly important in the countries of the Commonwealth of Independent States (CIS) as fiscal adjustment and structural reforms have taken root. Inflation has been brought down to relatively low levels in almost all of these countries, raising the question of what should be the appropriate nominal anchor at this stage. Formally, almost all CIS countries have floating exchange rate regimes, yet in practice they manage their exchange rates very heavily, perhaps be...

78 FR 59058 - Second Call for Nominations for the Wild Horse and Burro Advisory Board

Science.gov (United States)

2013-09-25

... connection with special needs for advice. Individuals may nominate themselves or others. Any individual or organization may nominate one or more persons to serve on the Board. Nominations will not be accepted without a... council of the BLM. If you are appointed as an advisor, the information will be retained by the appointing...

Comment on “Collision monochromatization in e^{+}e^{-} colliders”

Directory of Open Access Journals (Sweden)

D. Shatilov

2018-02-01

Full Text Available Bogomyagkov and Levichev [Phys. Rev. Accel. Beams 20, 051001 (2017PRABCJ2469-988810.1103/PhysRevAccelBeams.20.051001] have recently reported on monochromatization in collision schemes with crossing angle. From their results, in particular, it may seem that: (1 horizontal dispersion at the IP can provide monochromatization factor Λ≫1 while retaining Piwinski angle ϕ>1, (2 production rate in such a scheme for FCC-ee at 62.5 GeV can be larger than that in the nominal crab waist collision, and (3 strong rf focusing can be used for monochromatization purposes. We demonstrate here that the first two statements are not correct, and the last one is very doubtful.

7 CFR 1210.321 - Nominations and selection.

Science.gov (United States)

2010-01-01

... 7 Agriculture 10 2010-01-01 2010-01-01 false Nominations and selection. 1210.321 Section 1210.321 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING... PROMOTION PLAN Watermelon Research and Promotion Plan National Watermelon Promotion Board § 1210.321...

32 CFR 901.20 - Notice of nomination.

Science.gov (United States)

2010-07-01

...' nominations. If not previously received, USAFA/RRS forwards a precandidate questionnaire for completion. If the precandidate questionnaire indicates the potential to qualify for admission to the Academy or the... Candidate Personal Data Record; USAFA Form 147, AFA Candidate Activities Record; and USAFA Form 148, AFA...

Constructive Empiricism and Model Nominalism. | Udokang | Sophia ...

African Journals Online (AJOL)

James Ladyman has argued that constructive empiricism entails modal realism, and that this renders constructive empiricism untenable. We maintain that constructive empiricism is compatible with modal nominalism. Although the central term “observable” has been analyzed in terms of counterfactuals, and in general ...

Mechanical design for modification of a neutral beam for off-axis injection

Energy Technology Data Exchange (ETDEWEB)

Anderson, P.M. [General Atomics, P.O. Box 85608, San Diego, CA 92186-5608 (United States)], E-mail: anderson@fusion.gat.com; Hong, R.-M. [General Atomics, P.O. Box 85608, San Diego, CA 92186-5608 (United States)

2009-06-15

DIII-D is planning to implement off-axis neutral beam current drive by neutral beam injection through a midplane port at angles up to 15 deg. from horizontal. To accommodate the beam-line tilting, the following modifications are planned: (1) move the beam line away from the tokamak by 0.39 m to allow for a 0.68 m inside diameter welded bellows of necessary length to provide 15 deg. of vertical motion between the vessel port and the beam line; (2) reduce the vertical height of the injected beam from 0.48 m to 0.43 m to provide clearance for the inclined beam as it passes through the length of the vessel port; (3) add a linkage system between the front of the beam line and the tokamak to restrain the NB against the vacuum loading from the bellows while maintaining zero roll about the axis of the beam line as it is moved about a virtual pivot axis; (4) add a forward and two rear vertical actuators for raising and lowering the beam line (These actuators require coordinated position control to rotate the NB about a virtual pivot axis.); (5) incorporate lateral restraint to comply with seismic requirements.

A new measurement method for electrode gain in an orthogonally symmetric beam position monitor

International Nuclear Information System (INIS)

Zou Junying; Wu Fangfang; Yang Yongliang; Sun Baogen; Zhou Zeran; Luo Qing; Lu Ping; Xu Hongliang

2014-01-01

The new beam position monitor (BPM) system of the injector at the upgrade project of the Hefei Light Source (HLS Ⅱ) has 19 stripline beam position monitors. Most consist of four orthogonally symmetric stripline electrodes. Differences in electronic gain and mismaching tolerance can cause changes in the beam response of the BPM electrodes. This variation will couple the two measured horizontal positions, resulting in measuring error. To alleviate this effect, a new technique to measure the relative response of the four electrodes has been developed. It is independent of the beam charge, and the related coefficient can be calculated theoretically. The effect of electrode coupling on this technique is analyzed. The calibration data is used to fit the gain for all 19 injector beam position monitors. The results show the standard deviation of the distribution of measured gains is about 5%. (authors)

Turbulence measurement with a two-beam nacelle lidar

DEFF Research Database (Denmark)

Wagner, Rozenn; Sathe, Ameya; Mioullet, A.

The analysis of the turbulence intensity measurement is performed for a lidar measuring horizontally with two beams. First the turbulence intensity measured by such a system was evaluated theoretically. The Mann model of turbulence was used to evaluate the true value of the turbulence intensity...... of the wind speed and the main effects of the lidar measurement principles on turbulence intensity measurement were modeled: - A lidar senses the wind speed over the probe volume acting as a low pass-filter and thus cannot resolve high frequency turbulence; - The horizontal wind speed is retrieved from...... the combination of the radial speeds measured along two line-of-sights with different orientations; this results in the contamination of the lidar turbulence intensity measurement from the transverse component of the wind field. Secondly, the theoretical results were compared to experimental measurements. A two...

Nonsurgical management of horizontal root fracture associated external root resorption and internal root resorption

Directory of Open Access Journals (Sweden)

Shiraz Pasha

2016-01-01

Full Text Available Horizontal root fractures, which frequently affect the upper incisors, usually result from a frontal impact. As a result, combined injuries occur in dental tissues such as the pulp, dentin, cementum, periodontal ligament, and alveolar bone. Internal root canal inflammatory resorption involves a progressive loss of intraradicular dentin without adjunctive deposition of hard tissues adjacent to the resorptive sites. It is frequently associated with chronic pulpal inflammation, and bacteria might be identified from the granulation tissues when the lesion is progressive to the extent that it is identifiable with routine radiographs. With the advancement in technology, it is imperative to use modern diagnostic tools such as cone beam computed tomography and radiovisuography to diagnose and confirm the presence and extent of resorptions and fractures and their exact location. This case report presents a rare case having internal root resorption and horizontal root fracture with external inflammatory root resorption both which were treated successfully following guidelines by International Association of Dental Traumatology by nonsurgical treatment with 1 year follow-up.

Pilot Quality Control Program for Audit RT External Beams at Mexican Hospitals

International Nuclear Information System (INIS)

Alvarez R, J T; Tovar M, V M

2008-01-01

A pilot quality control program for audit 18 radiotherapy RT external beams at 13 Mexican hospitals is described--for eleven 60 Co beams and seven photon beams of 6, 10 and 15 MV from accelerators. This program contains five parts: a) Preparation of the TLD-100 powder: washing, drying and annealing (one hour 400 deg. C plus 24 hrs 80 deg. C). b) Sending two IAEA type capsules to the hospitals for irradiation at the hospital to a nominal D W = 2 Gy·c) Preparation at the SSDL of ten calibration curves CC in the range of 0.5 Gy to 6 Gy in terms of absorbed dose to water D W for 60 Co with traceability to primary laboratory NRC (Canada), according to a window irradiation: 26/10/2007-7/12/2007. d) Reading all capsules that match their hospital time irradiation and the SSDL window irradiation. f) Evaluation of the Dw imparted by the hospitals

Pilot Quality Control Program for Audit RT External Beams at Mexican Hospitals

Science.gov (United States)

Álvarez R., J. T.; Tovar M., V. M.

2008-08-01

A pilot quality control program for audit 18 radiotherapy RT external beams at 13 Mexican hospitals is described—for eleven 60 Co beams and seven photon beams of 6, 10 and 15 MV from accelerators. This program contains five parts: a) Preparation of the TLD-100 powder: washing, drying and annealing (one hour 400 °C plus 24 hrs 80 °C). b) Sending two IAEA type capsules to the hospitals for irradiation at the hospital to a nominal DW = 2 Gy ṡ c ) Preparation at the SSDL of ten calibration curves CC in the range of 0.5 Gy to 6 Gy in terms of absorbed dose to water DW for 60 Co with traceability to primary laboratory NRC (Canada), according to a window irradiation: 26/10/2007-7/12/2007. d) Reading all capsules that match their hospital time irradiation and the SSDL window irradiation. f) Evaluation of the Dw imparted by the hospitals.

EPICS Controlled Collimator for Controlling Beam Sizes in HIPPO

Energy Technology Data Exchange (ETDEWEB)

Napolitano, Arthur Soriano [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Vogel, Sven C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-08-03

Controlling the beam spot size and shape in a diffraction experiment determines the probed sample volume. The HIPPO - High-Pressure-Preferred Orientation– neutron time-offlight diffractometer is located at the Lujan Neutron Scattering Center in Los Alamos National Laboratories. HIPPO characterizes microstructural parameters, such as phase composition, strains, grain size, or texture, of bulk (cm-sized) samples. In the current setup, the beam spot has a 10 mm diameter. Using a collimator, consisting of two pairs of neutron absorbing boron-nitride slabs, horizontal and vertical dimensions of a rectangular beam spot can be defined. Using the HIPPO robotic sample changer for sample motion, the collimator would enable scanning of e.g. cylindrical samples along the cylinder axis by probing slices of such samples. The project presented here describes implementation of such a collimator, in particular the motion control software. We utilized the EPICS (Experimental Physics Interface and Control System) software interface to integrate the collimator control into the HIPPO instrument control system. Using EPICS, commands are sent to commercial stepper motors that move the beam windows.

Combined VIS-IR spectrometer with vertical probe beam

Science.gov (United States)

Protopopov, V.

2017-12-01

A prototype of a combined visible-infrared spectrometer with a vertical probe beam is designed and tested. The combined spectral range is 0.4-20 μ with spatial resolution 1 mm. Basic features include the ability to measure both visibly transparent and opaque substances, as well as buried structures, such as in semiconductor industry; horizontal orientation of a sample, including semiconductor wafers; and reflection mode of operation, delivering twice the sensitivity compared to the transmission mode.

Beam position monitoring in the AGS Linac to Booster transfer line

International Nuclear Information System (INIS)

Shea, T.J.; Brodowski, J.; Witkover, R.

1991-01-01

A beam position monitor system has been developed and used in the commissioning of Brookhaven's Linac to Booster transfer line. This line transports a chopped, RF modulated H- beam from the 200 MeV Linac to the AGS Booster. Over a 15dB dynamic range in beam current, the position monitor system provides a real-time, normalized position signal with an analog bandwidth of about 20 MHz. Seven directional coupler style pickups are installed in the line with each pickup sensing both horizontal and vertical position. Analog processing electronics are located in the tunnel and incorporate the amplitude modulation to phase modulation normalization technique. To avoid interference from the 200 MHz linac RF system, processing is performed at 400 MHz. This paper provides a system overview and report results from the commissioning experience

Control of the Dipole Cold Mass Geometry at CERN to Optimize LHC Performance

CERN Document Server

Wildner, E; La China, M; Tommasini, D

2006-01-01

The detailed shape of the 15 m long superconducting LHC dipole cold mass is of high importance as it determines three key parameters: the beam aperture, nominally of the order of 10 beam standard deviations; the connectivity of the beam- and technical lines between magnets; the transverse position of non-linear correctors mounted on the dipole ends. An offset of the latter produces unwanted beam dynamics perturbations. The tolerances are in the order of mm over the length of the magnet. The natural flexibility of the dipole and its mechanical structure allow deformations during handling and transportation which exceed the tolerances. This paper presents the observed deformations of the geometry during handling and various operations at CERN, deformations which are interpreted thanks to a simple mechanical model. These observations have led to a strategy of dipole geometry control at CERN, based on adjustment of the position of its central support (the dipole is supported at three positions, horizontally and v...

Design of an interaction region with head-on collisions for the ILC

CERN Document Server

Appleby, R; Jackson, F; Alabau-Pons, M; Bambade, P; Brossard, J; Dadoun, O; Rimbault, C; Keller, L; Nosochkov, Y; Seryi, Andrei; Payet, J; Napoly, O; Rippon, C; Uriot, D

2006-01-01

An interaction region (IR) with head-on collisions is considered as an alternative to the baseline configuration of the International Linear Collider (ILC) which includes two IRs with finite crossing-angles (2 and 20 mrad). Although more challenging for the beam extraction, the head-on scheme is favoured by the experiments because it allows a more convenient detector configuration, particularly in the forward region. The optics of the head-on extraction is revisited by separating the e+ and e- beams horizontally, first by electrostatic separators operated at their LEP nominal field and then using a defocusing quadrupole of the final focus beam line. In this way the septum magnet is protected from the beamstrahlung power. Newly optimized final focus and extraction optics are presented, including a first look at post-collision diagnostics. The influence of parasitic collisions is shown to lead to a region of stable collision parameters. Disrupted beam and beamstrahlung photon losses are calculated along the ext...

HORIZONTAL WELL DRILL-IN FLUIDS

Directory of Open Access Journals (Sweden)

Nediljka Gaurina-Međimurec

1998-12-01

Full Text Available Main objective of horizontal driling is to place a drain-hole for a long distance within the pay zone to enhance productivity or injectivity. In drilling horizontal wells, more serious problems appear than in drilling vertical wells. These problems are: poor hole cleaning, excessive torque and drag, hole filling, pipe stucking, wellbore instability, loss of circulation, formation damage, poor cement job, and difficulties at logging jobs. From that reason, successful drilling and production of horizontal well depends largely on the fluid used during drilling and completion phases. Several new fluids, that fulfill some or all of required properties (hole cleaning, cutting suspension, good lubrication, and relative low formation damage, are presented in this paper.

Rf beam control for the AGS Booster

International Nuclear Information System (INIS)

Brennan, J.M.

1994-01-01

RF beam control systems for hadron synchrotrons have evolved over the past three decades into an essentially standard design. The key difference between hadron and lepton machines is the absence of radiation damping and existence of significant frequency variation in the case of hadrons. Although the motion of the hadron in the potential well of the rf wave is inherently stable it is not strongly damped. Damping must be provided by electronic feedback through the accelerating system. This feedback is typically called the phase loop. The technology of the rf beam control system for the AGS Booster synchrotron is described. First, the overall philosophy of the design is explained in terms of a conventional servo system that regulates the beam horizontal position in the vacuum chamber. The concept of beam transfer functions is fundamental to the mathematics of the design process and is reviewed. The beam transfer functions required for this design are derived from first principles. An overview of the beam signal pick-ups and high level rf equipment is given. The major subsystems, the frequency program, the heterodyne system, and beam feedback loops, are described in detail. Beyond accelerating the beam, the rf system must also synchronize the bunches in the Booster to the buckets in the AGS before transfer. The technical challenge in this process is heightened by the need to accomplish synchronization while the frequency is still changing. Details of the synchronization system are given. This report is intended to serve two purposes. One is to document the hardware and performance of the systems that have been built. The other is to serve as a tutorial vehicle from which the non-expert can not only learn the details of this system but also learn the principles of beam control that have led to the particular design choices made

Rf beam control for the AGS Booster

Energy Technology Data Exchange (ETDEWEB)

Brennan, J.M.

1994-09-26

RF beam control systems for hadron synchrotrons have evolved over the past three decades into an essentially standard design. The key difference between hadron and lepton machines is the absence of radiation damping and existence of significant frequency variation in the case of hadrons. Although the motion of the hadron in the potential well of the rf wave is inherently stable it is not strongly damped. Damping must be provided by electronic feedback through the accelerating system. This feedback is typically called the phase loop. The technology of the rf beam control system for the AGS Booster synchrotron is described. First, the overall philosophy of the design is explained in terms of a conventional servo system that regulates the beam horizontal position in the vacuum chamber. The concept of beam transfer functions is fundamental to the mathematics of the design process and is reviewed. The beam transfer functions required for this design are derived from first principles. An overview of the beam signal pick-ups and high level rf equipment is given. The major subsystems, the frequency program, the heterodyne system, and beam feedback loops, are described in detail. Beyond accelerating the beam, the rf system must also synchronize the bunches in the Booster to the buckets in the AGS before transfer. The technical challenge in this process is heightened by the need to accomplish synchronization while the frequency is still changing. Details of the synchronization system are given. This report is intended to serve two purposes. One is to document the hardware and performance of the systems that have been built. The other is to serve as a tutorial vehicle from which the non-expert can not only learn the details of this system but also learn the principles of beam control that have led to the particular design choices made.

Productivity and injectivity of horizontal wells

Energy Technology Data Exchange (ETDEWEB)

Aziz, Khalid

2000-03-06

One of the key issues addressed was pressure drop in long horizontal wells and its influence on well performance. Very little information is available in the literature on flow in pipes with influx through pipe walls. Virtually all of this work has been in small diameter pipes and with single-phase flow. In order to address this problem new experimental data on flow in horizontal and near horizontal wells have been obtained. Experiments were conducted at an industrial facility on typical 6 1/8 ID, 100 feet long horizontal well model. The new data along with available information in the literature have been used to develop new correlations and mechanistic models. Thus it is now possible to predict, within reasonable accuracy, the effect of influx through the well on pressure drop in the well.

Comparative Study of the Tuning Performances of the Nominal and Long L* CLIC Final Focus System at √s = 380 GeV

CERN Document Server

Plassard, F; Marin, E; Tomás, R

2017-01-01

Mitigation of static imperfections for emittance preservation is one of the most important and challenging tasks faced by the Compact Linear Collider (CLIC) beam delivery system. A simulation campaign has been performed to recover the nominal luminosity by means of different alignment procedures. The state of the art of the tuning studies is drawn up. Comparative studies of the tuning performances and a tuning-based final focus system design optimization for two L options are presented. The effectiveness of the tuning techniques applied to these different lattices will be decisive for the final layout of the CLIC final focus system at √s = 380 GeV.

Alternative stitching method for massively parallel e-beam lithography

Science.gov (United States)

Brandt, Pieter; Tranquillin, Céline; Wieland, Marco; Bayle, Sébastien; Milléquant, Matthieu; Renault, Guillaume

2015-07-01

In this study, a stitching method other than soft edge (SE) and smart boundary (SB) is introduced and benchmarked against SE. The method is based on locally enhanced exposure latitude without throughput cost, making use of the fact that the two beams that pass through the stitching region can deposit up to 2× the nominal dose. The method requires a complex proximity effect correction that takes a preset stitching dose profile into account. Although the principle of the presented stitching method can be multibeam (lithography) systems in general, in this study, the MAPPER FLX 1200 tool is specifically considered. For the latter tool at a metal clip at minimum half-pitch of 32 nm, the stitching method effectively mitigates beam-to-beam (B2B) position errors such that they do not induce an increase in critical dimension uniformity (CDU). In other words, the same CDU can be realized inside the stitching region as outside the stitching region. For the SE method, the CDU inside is 0.3 nm higher than outside the stitching region. A 5-nm direct overlay impact from the B2B position errors cannot be reduced by a stitching strategy.

Fabrication of a Horizontal and a Vertical Large Surface Area Nanogap Electrochemical Sensor

Directory of Open Access Journals (Sweden)

Jules L. Hammond

2016-12-01

Full Text Available Nanogap sensors have a wide range of applications as they can provide accurate direct detection of biomolecules through impedimetric or amperometric signals. Signal response from nanogap sensors is dependent on both the electrode spacing and surface area. However, creating large surface area nanogap sensors presents several challenges during fabrication. We show two different approaches to achieve both horizontal and vertical coplanar nanogap geometries. In the first method we use electron-beam lithography (EBL to pattern an 11 mm long serpentine nanogap (215 nm between two electrodes. For the second method we use inductively-coupled plasma (ICP reactive ion etching (RIE to create a channel in a silicon substrate, optically pattern a buried 1.0 mm × 1.5 mm electrode before anodically bonding a second identical electrode, patterned on glass, directly above. The devices have a wide range of applicability in different sensing techniques with the large area nanogaps presenting advantages over other devices of the same family. As a case study we explore the detection of peptide nucleic acid (PNA−DNA binding events using dielectric spectroscopy with the horizontal coplanar device.

Performance of horizontal versus vertical vapor extraction wells

International Nuclear Information System (INIS)

Birdsell, K.H.; Roseberg, N.D.; Edlund, K.M.

1994-06-01

Vapor extraction wells used for site remediation of volatile organic chemicals in the vadose zone are typically vertical wells. Over the past few years, there has been an increased interest in horizontal wells for environmental remediation. Despite the interest and potential benefits of horizontal wells, there has been little study of the relative performance of horizontal and vertical vapor extraction wells. This study uses numerical simulations to investigate the relative performance of horizontal versus vertical vapor extraction wells under a variety of conditions. The most significant conclusion that can be drawn from this study is that in a homogeneous medium, a single, horizontal vapor extraction well outperforms a single, vertical vapor extraction well (with surface capping) only for long, linear plumes. Guidelines are presented regarding the use of horizontal wells

Production of intense negative ion beams in magnetically insulated diodes

International Nuclear Information System (INIS)

Lindenbaum, H.

1988-01-01

Production of intense negative ion beams in magnetically insulated diodes was studied in order to develop an understanding of this process by measuring the ion-beam parameters as a function of diode and cathode plasma conditions in different magnetically insulated diodes. A coral diode, a racetrack diode, and an annular diode were used. The UCI APEX pulse line, with a nominal output of 1MV, 140kA, was used under matched conditions with a pulse length of 50 nsec. Negative-ion intensity and divergence were measured with Faraday cups and CR-39 track detectors. Cathode plasma was produced by passive dielectric cathodes and later, by an independent plasma gun. Negative-ion currents had an intensity of a few A/cm 2 with a divergence ranging between a few tenths milliradians for an active TiH 2 plasma gun and 300 milliradians for a passive polyethelene cathode. Negative ions were usually emitted from a few hot spots on the cathode surface. These hot spots are believed to cause transverse electrical fields in the diode gap responsible for the beam divergence. Mass spectrometry measurements showed that the ion beam consists of mainly H - ions when using a polyethelene or a TiH 2 cathodes, and mainly of negative carbon ions when using a carbon cathode

Microcontroller based four-channel current readout unit for beam slit monitor

International Nuclear Information System (INIS)

Holikatti, A.C.; Puntambekar, T.A.; Pithawa, C.K.

2009-01-01

This paper describes the design and development of a microcontroller based four-channel current readout unit for Beam Slit Monitor (BSM) installed in Transport Line-1 of Indus Accelerator Complex. BSM is a diagnostic device consisting of two horizontal and two vertical blades, which can be moved independently in to the beam pipe to cut the beam transversely. The readout unit employs switched integrators with reset, hold and select switches and timing and control unit. It integrates the current output of the four blades of BSM and produces an output corresponding to the beam charge intercepted by the blade. The integrator outputs are then multiplexed and digitized using 12-bit ADC. Acquired digital data from ADC is stored into on-chip RAM of the microcontroller. The readout sequence is synchronized with the Microtron beam-timing signal. The timing of integration, hold and reset cycles is controlled by the microcontroller. The unit is connected on a serial link to the host computer in main control room. This unit has been integrated with the BSM system and is being used to obtain the electron beam profile. (author)

Implications of Nash Bargaining for Horizontal Industry Integration

OpenAIRE

Richard E. Just; Siddhartha Mitra; Sinaia Netanyahu

2005-01-01

This article shows how horizontal industry integration can arise from transferable asymmetry of technologies and endowments. The Nash bargaining solution suggests that greater technological diversity among coordinating parties yields greater gains from horizontal integration. The framework fits the case where a firm with a superior technology franchises the technology by horizontal integration. The results appear to fit hog production where integration has been primarily horizontal and, in pa...

Geological nominations at UNESCO World Heritage, an upstream struggle

Science.gov (United States)

Olive-Garcia, Cécile; van Wyk de Vries, Benjamin

2017-04-01

Using my 10 years experience in setting up and defending a UNESCO world Heritage Geological nomination, this presentation aims to give a personal insight into this international process and the differential use of science, subjective perception (aesthetic and 'naturality'), and politics. At this point in the process, new protocols have been tested in order to improve the dialogue, accountability and transparency between the different stake-holders. These are, the State parties, the IUCN, the scientific community, and UNESCO itself. Our proposal is the Chaîne des Puys-Limagne fault ensemble, which combines tectonic, geomorphological evolution and volcanology. The project's essence is a conjunction of inseparable geological features and processes, set in the context of plate tectonics. This very unicit yof diverse forms and processes creates the value of the site. However, it is just this that has caused a problem, as the advisory body has a categorical approach of nominations that separates items to assess them in an unconnected manner.From the start we proposed a combined approach, where a property is seen in its entirety, and the constituent elements seen as interlinked elements reflecting the joint underlying phenomena. At this point, our project has received the first ever open review by an independent technical mission (jointly set up by IUCN, UNESCO and the State party). The subsequent report was broadly supportive of the project's approach and of the value of the ensemble of features. The UNESCO committee in 2016, re-referred the nomination, acknowledging the potential Outstanding Universal Value of the site and requesting the parties to continue the upstream process (e.g. collaborative work), notably on the recommendations and conclusions of the Independent Technical mission report. Meetings are continuing, and I shall provide you with the hot-off-the-press news as this ground breaking nomination progresses.

THE NOMINAL PREDICATE (ALBANIAN - ENGLISH)

OpenAIRE

Shkelqim Millaku

2017-01-01

The aim of this paper is to description the nominal of predicate between two languages (Albanian – English). The purpose of the following discussing is to show that some noun phrases, namely predicate nominal’s, do not seem to exhibit. What is considering the typical behavior of noun phrase? First, they do not seem to be assigned case. Second, they may not assign are roles in normal sense so that they are probably as Theta-marker arguments, unlike referential Noun Phrases.[1] In Albanian lang...

An FPGA Based Multiprocessing CPU for Beam Synchronous Timing in CERN's SPS and LHC

CERN Document Server

Ballester, F J; Gras, J J; Lewis, J; Savioz, J J; Serrano, J

2003-01-01

The Beam Synchronous Timing system (BST) will be used around the LHC and its injector, the SPS, to broadcast timing meassages and synchronize actions with the beam in different receivers. To achieve beam synchronization, the BST Master card encodes messages using the bunch clock, with a nominal value of 40.079 MHz for the LHC. These messages are produced by a set of tasks every revolution period, which is every 89 us for the LHC and every 23 us for the SPS, therefore imposing a hard real-time constraint on the system. To achieve determinism, the BST Master uses a dedicated CPU inside its main Field Programmable Gate Array (FPGA) featuring zero-delay hardware task switching and a reduced instruction set. This paper describes the BST Master card, stressing the main FPGA design, as well as the associated software, including the LynxOS driver and the tailor-made assembler.

Improved design and in-situ measurements of new beam position monitors for Indus-2

Science.gov (United States)

Kumar, M.; Babbar, L. K.; Holikatti, A. C.; Yadav, S.; Tyagi, Y.; Puntambekar, T. A.; Senecha, V. K.

2018-01-01

Beam position monitors (BPM) are important diagnostic devices used in particle accelerators to monitor position of the beam for various applications. Improved version of button electrode BPM has been designed using CST Studio Suite for Indus-2 ring. The new BPMs are designed to replace old BPMs which were designed and installed more than 12 years back. The improved BPMs have higher transfer impedance, resonance free output signal, equal sensitivity in horizontal and vertical planes and fast decaying wakefield as compared to old BPMs. The new BPMs have been calibrated using coaxial wire method. Measurement of transfer impedance and time domain signals has also been performed in-situ with electron beam during Indus-2 operation. The calibration and beam based measurements results showed close agreement with the design parameters. This paper presents design, electromagnetic simulations, calibration result and in-situ beam based measurements of newly designed BPMs.

76 FR 45555 - Nominations to the FIFRA Scientific Advisory Panel; Request for Comments

Science.gov (United States)

2011-07-29

... data of persons nominated to serve on the Scientific Advisory Panel (SAP) established under section 25... and the NSF nominate scientists to fill vacancies occurring on the Panel. The Agency requested... Health Science Advisor in the Division of Specialized Information Services at the National Library of...

Precision analog signal processor for beam position measurements in electron storage rings

International Nuclear Information System (INIS)

Hinkson, J.A.; Unser, K.B.

1995-01-01

Beam position monitors (BPM) in electron and positron storage rings have evolved from simple systems composed of beam pickups, coaxial cables, multiplexing relays, and a single receiver (usually a analyzer) into very complex and costly systems of multiple receivers and processors. The older may have taken minutes to measure the circulating beam closed orbit. Today instrumentation designers are required to provide high-speed measurements of the beam orbit, often at the ring revolution frequency. In addition the instruments must have very high accuracy and resolution. A BPM has been developed for the Advanced Light Source (ALS) in Berkeley which features high resolution and relatively low cost. The instrument has a single purpose; to measure position of a stable stored beam. Because the pickup signals are multiplexed into a single receiver, and due to its narrow bandwidth, the receiver is not intended for single-turn studies. The receiver delivers normalized measurements of X and Y posit ion entirely by analog means at nominally 1 V/mm. No computers are involved. No software is required. Bergoz, a French company specializing in precision beam instrumentation, integrated the ALS design m their new BPM analog signal processor module. Performance comparisons were made on the ALS. In this paper we report on the architecture and performance of the ALS prototype BPM

ACCELERATORS: Beam based alignment of the SSRF storage ring

Science.gov (United States)

Zhang, Man-Zhou; Li, Hao-Hu; Jiang, Bo-Cheng; Liu, Gui-Min; Li, De-Ming

2009-04-01

There are 140 beam position monitors (BPMs) in the Shanghai Synchrotron Radiation Facility (SSRF) storage ring used for measuring the closed orbit. As the BPM pickup electrodes are assembled directly on the vacuum chamber, it is important to calibrate the electrical center offset of the BPM to an adjacent quadrupole magnetic center. A beam based alignment (BBA) method which varies individual quadrupole magnet strength and observes its effects on the orbit is used to measure the BPM offsets in both the horizontal and vertical planes. It is a completely automated technique with various data processing methods. There are several parameters such as the strength change of the correctors and the quadrupoles which should be chosen carefully in real measurement. After several rounds of BBA measurement and closed orbit correction, these offsets are set to an accuracy better than 10 μm. In this paper we present the method of beam based calibration of BPMs, the experimental results of the SSRF storage ring, and the error analysis.

78 FR 39768 - Notice of Call for Nominations for the Wild Horse and Burro Advisory Board

Science.gov (United States)

2013-07-02

... special needs for advice. Individuals may nominate themselves or others. Any individual or organization may nominate one or more persons to serve on the Board. Nominations will not be accepted without a... advisory council of the BLM. If you are appointed as an advisor, the information will be retained by the...

Secondary magnetic field harmonics dependence on vacuum beam chamber geometry

Directory of Open Access Journals (Sweden)

S. Y. Shim

2013-08-01

Full Text Available The harmonic magnetic field properties due to eddy currents have been studied with respect to the geometry of the vacuum beam chamber. We derived a generalized formula enabling the precise prediction of any field harmonics generated by eddy currents in beam tubes with different cross-sectional geometries. Applying our model to study the properties of field harmonics in beam tubes with linear dipole magnetic field ramping clearly proved that the circular cross section tube generates only a dipole field from eddy currents. The elliptic tube showed noticeable magnitudes of sextupole and dipole fields. We demonstrate theoretically that it is feasible to suppress the generation of the sextupole field component by appropriately varying the tube wall thickness as a function of angle around the tube circumference. This result indicates that it is possible to design an elliptical-shaped beam tube that generates a dipole field component with zero magnitude of sextupole. In a rectangular-shaped beam tube, one of the selected harmonic fields can be prevented if an appropriate wall thickness ratio between the horizontal and vertical tube walls is properly chosen. Our generalized formalism can be used for optimization of arbitrarily complex-shaped beam tubes, with respect to suppression of detrimental field harmonics.

Production of a Beam of Highly Vibrationally Excited CO Using Perturbations

Science.gov (United States)

Bartels, N.; Schäfer, T.; Hühnert, J.; Wodtke, A. M.; Field, R. W.

2012-06-01

For many experimentalists (especially those, who are not spectroscopists), molecular pertubations are a curse, as they make assignments and analysis of spectral data more difficult. Nevertheless, they can also be a boon! In this talk we will show how a molecular beam of CO in high vibrational states (v=17,18) can be prepared by an optical pumping scheme that we call PUMP-PUMP-PERTURB and DUMP (P^3D). P^3D exploits the loaning, via spin-orbit perturbations, of the large oscillator strength of the 4th positive system, A ^1 π ← X ^1 Σ ^+, to the triplet manifold. This allows some nominally spin-forbidden transitions to be exploited in multistep optical pumping schemes. The ability to {state-selectively} prepare CO in high vibrational states opens up new opportunities for molecular beam scattering experiments.

What's in a name? Nominative determinism in the UK dental workforce.

Science.gov (United States)

Sleigh, J

2016-12-16

Background Nominative determinism describes the theory that people are more likely to pursue careers that are connected to their names. Compelling research has been carried out across the medical professions that provides strong evidence for this phenomenon, but as yet its applicability to the UK dental workforce remains unknown.Aim The aim of this study was to establish the prevalence of dentally-related surnames in the UK dental workforce (dentists and dental care professionals) and compare this to the UK population.Results Dentistry may provide a surprising counter-example to prevailing theories of nominative determinism, as UK dentists are significantly less likely than the UK general population to have dentally-related surnames. This new phenomenon of 'nominative antideterminism' was not observed in the dental care professional (DCP) cohort, for whom the prevalence of dentally-related surnames was similar to that in the wider UK population.