WorldWideScience

Sample records for scattering spectrometer beam

  1. Computer control in a compton scattering spectrometer

    International Nuclear Information System (INIS)

    Cui Ningzhuo; Chen Tao; Gong Zhufang; Yang Baozhong; Mo Haiding; Hua Wei; Bian Zuhe

    1995-01-01

    The authors introduced the hardware and software of computer autocontrol of calibration and data acquisition in a Compton Scattering spectrometer which consists of a HPGe detector, Amplifiers and a MCA

  2. The Harwell back-scattering spectrometer

    International Nuclear Information System (INIS)

    Windsor, C.G.; Bunce, L.J.; Borcherds, P.H.; Cole, I.; Fitzmaurice, M.; Johnson, D.A.G.; Sinclair, R.N.

    1976-01-01

    Neutron diffraction spectra in which both high resolution (Δ Q/Q approximately equal to 0.003) and high intensity are maintained up to scattering vectors as high as 30A -1 (sin theta/lambda = 2.5) have been obtained with the back-scattering spectrometer (BSS) recently installed on the Harwell electron linac. The theory behind the spectrometer design is described, and it is shown how the above resolution requirement leads to its basic features of a 12m incident flight path, a 2m scattering flight path and a scattering angle (2theta) acceptance from 165 0 to 175 0 . Examples of the resolution, intensity and background are given. It is shown that the problem of frame overlap may be overcome by using an absorbing filter. (author)

  3. Molecular-beam scattering

    International Nuclear Information System (INIS)

    Vernon, M.F.

    1983-07-01

    The molecular-beam technique has been used in three different experimental arrangements to study a wide range of inter-atomic and molecular forces. Chapter 1 reports results of a low-energy (0.2 kcal/mole) elastic-scattering study of the He-Ar pair potential. The purpose of the study was to accurately characterize the shape of the potential in the well region, by scattering slow He atoms produced by expanding a mixture of He in N 2 from a cooled nozzle. Chapter 2 contains measurements of the vibrational predissociation spectra and product translational energy for clusters of water, benzene, and ammonia. The experiments show that most of the product energy remains in the internal molecular motions. Chapter 3 presents measurements of the reaction Na + HCl → NaCl + H at collision energies of 5.38 and 19.4 kcal/mole. This is the first study to resolve both scattering angle and velocity for the reaction of a short lived (16 nsec) electronic excited state. Descriptions are given of computer programs written to analyze molecular-beam expansions to extract information characterizing their velocity distributions, and to calculate accurate laboratory elastic-scattering differential cross sections accounting for the finite apparatus resolution. Experimental results which attempted to determine the efficiency of optically pumping the Li(2 2 P/sub 3/2/) and Na(3 2 P/sub 3/2/) excited states are given. A simple three-level model for predicting the steady-state fraction of atoms in the excited state is included

  4. A compact multichannel spectrometer for Thomson scattering

    Energy Technology Data Exchange (ETDEWEB)

    Schoenbeck, N. L.; Schlossberg, D. J.; Dowd, A. S.; Fonck, R. J.; Winz, G. R. [Department of Engineering Physics, University of Wisconsin, Madison, Wisconsin 53706 (United States)

    2012-10-15

    The availability of high-efficiency volume phase holographic (VPH) gratings and intensified CCD (ICCD) cameras have motivated a simplified, compact spectrometer for Thomson scattering detection. Measurements of T{sub e} < 100 eV are achieved by a 2971 l/mm VPH grating and measurements T{sub e} > 100 eV by a 2072 l/mm VPH grating. The spectrometer uses a fast-gated ({approx}2 ns) ICCD camera for detection. A Gen III image intensifier provides {approx}45% quantum efficiency in the visible region. The total read noise of the image is reduced by on-chip binning of the CCD to match the 8 spatial channels and the 10 spectral bins on the camera. Three spectrometers provide a minimum of 12 spatial channels and 12 channels for background subtraction.

  5. A compact multichannel spectrometer for Thomson scattering

    International Nuclear Information System (INIS)

    Schoenbeck, N. L.; Schlossberg, D. J.; Dowd, A. S.; Fonck, R. J.; Winz, G. R.

    2012-01-01

    The availability of high-efficiency volume phase holographic (VPH) gratings and intensified CCD (ICCD) cameras have motivated a simplified, compact spectrometer for Thomson scattering detection. Measurements of T e e > 100 eV by a 2072 l/mm VPH grating. The spectrometer uses a fast-gated (∼2 ns) ICCD camera for detection. A Gen III image intensifier provides ∼45% quantum efficiency in the visible region. The total read noise of the image is reduced by on-chip binning of the CCD to match the 8 spatial channels and the 10 spectral bins on the camera. Three spectrometers provide a minimum of 12 spatial channels and 12 channels for background subtraction.

  6. A compact multichannel spectrometer for Thomson scattering.

    Science.gov (United States)

    Schoenbeck, N L; Schlossberg, D J; Dowd, A S; Fonck, R J; Winz, G R

    2012-10-01

    The availability of high-efficiency volume phase holographic (VPH) gratings and intensified CCD (ICCD) cameras have motivated a simplified, compact spectrometer for Thomson scattering detection. Measurements of T(e) VPH grating and measurements T(e) > 100 eV by a 2072 l∕mm VPH grating. The spectrometer uses a fast-gated (~2 ns) ICCD camera for detection. A Gen III image intensifier provides ~45% quantum efficiency in the visible region. The total read noise of the image is reduced by on-chip binning of the CCD to match the 8 spatial channels and the 10 spectral bins on the camera. Three spectrometers provide a minimum of 12 spatial channels and 12 channels for background subtraction.

  7. Beam analysis spectrometer for relativistic heavy ions

    International Nuclear Information System (INIS)

    Schimmerling, W.; Subramanian, T.S.; McDonald, W.J.; Kaplan, S.N.; Sadoff, A.; Gabor, G.

    1983-01-01

    A versatile spectrometer useful for measuring the mass, charge, energy, fluence and angular distribution of primaries and fragments associated with relativistic heavy ion beams is described. The apparatus is designed to provide accurate physical data for biology experiments and medical therapy planning as a function of depth in tissue. The spectrometer can also be used to measure W, the average energy to produce an ion pair, range-energy, dE/dx, and removal cross section data of interest in nuclear physics. (orig.)

  8. Spectrometer for neutron inelastic scattering investigations of microsamples

    International Nuclear Information System (INIS)

    Balagurov, A.M.; Kozlenko, D.P.; Platonov, S.L.; Savenko, B.N.; Glazkov, V.P.; Krasnikov, Yu.M.; Naumov, I.V.; Pukhov, A.V.; Somenkov, V.A.; Syrykh, G.F.

    1997-01-01

    A new neutron spectrometer for investigation of inelastic neutron scattering on polycrystal microsamples under high pressure in sapphire and diamond anvils cells is described. The spectrometer is operating at the IBR-2 pulsed reactor in JINR. Parameters and methodical peculiarities of the spectrometer and the examples of experimental studies are given. (author)

  9. [Design of Dual-Beam Spectrometer in Spectrophotometer for Colorimetry].

    Science.gov (United States)

    Liu, Yi-xuan; Yan, Chang-xiang

    2015-07-01

    Spectrophotometers for colorimetry are usually composed of two independent and identical spectrometers. In order to reduce the volume of spectrophotometer for colorimetry, a design method of double-beam spectrometer is put forward. A traditional spectrometer is modified so that a new spectrometer can realize the function of double spectrometers, which is especially suitable for portable instruments. One slit is replaced by the double-slit, than two beams of spectrum can be detected. The working principle and design requirement of double-beam spectrometer are described. A spectrometer of portable spectrophotometer is designed by this method. A toroidal imaging mirror is used for the Czerny-Turner double-beam spectrometer in this paper, which can better correct astigmatism, and prevent the dual-beam spectral crosstalk. The results demonstrate that the double-beam spectrometer designed by this method meets the design specifications, with the spectral resolution less than 10 nm, the spectral length of 9.12 mm, and the volume of 57 mm x 54 mm x 23 mm, and without the dual-beam spectral overlap in the detector either. Comparing with a traditional spectrophotometer, the modified spectrophotometer uses a set of double-beam spectrometer instead of two sets of spectrometers, which can greatly reduce the volume. This design method can be specially applied in portable spectrophotometers, also can be widely applied in other double-beam spectrophotometers, which offers a new idea for the design of dual-beam spectrophotometers.

  10. Spectrometer magnet for experiment NA4 (deep inelastic muon scattering)

    CERN Multimedia

    CERN PhotoLab

    1977-01-01

    This is one section of the toroidal-field spectrometer magnet of experiment NA4 (deep inelastic muon scattering), shown here during the installation period and later located in the North Area of the SPS. To see all 4 sections, select 7709201. Igor Savin from Dubna looks at what his lab had provided: the huge iron disks were machined at and provided by Dubna. Multi-Wire Proportional Chambers were installed in the gaps between the packs of 4 disks. When the beam from the SPS struck the target (to the right in this picture), the iron would quickly stop the hadronic shower, whilst the muons would go on, performing oscillations in the toroidal field. NA4 was a CERN-Dubna-Munich-Saclay (later also Bologna) collaboration, spokesman: Carlo Rubbia.

  11. MAGNETIC SPECTROMETER DESIGN FOR ELECTRON SCATTERING ABOVE 1 Bev

    Energy Technology Data Exchange (ETDEWEB)

    Schopper, H.

    1963-06-15

    Design considerations are discussed for magnetic spectrometer electron scattering investigations with the higher energy (above 1 Bev) electron sources which are being developed. The spectrometers are to be used to discriminate between elastic and inelastic processes. A momentum resolution of the order of one per cent is required for these experiments. Various spectrometers are compared according to their optical properties and the number of magnets they consist of. (R.E.U.)

  12. Improved kaon beam and spectrometer for the AGS

    International Nuclear Information System (INIS)

    Hungerford, E.V. III.

    1979-01-01

    The properties of the existing low energy separated kaon beams at the Brookhaven AGS, and the preliminary plans to construct an improved kaon beam line with a high resolution spectrometer for this facility are reported. 10 references

  13. High resolving power spectrometer for beam analysis

    International Nuclear Information System (INIS)

    Moshammer, H.W.; Spencer, J.E.

    1992-03-01

    We describe a system designed to analyze the high energy, closely spaced bunches from individual RF pulses. Neither a large solid angle nor momentum range is required so this allows characteristics that appear useful for other applications such as ion beam lithography. The spectrometer is a compact, double-focusing QBQ design whose symmetry allows the Quads to range between F or D with a correspondingly large range of magnifications, dispersion and resolving power. This flexibility insures the possibility of spatially separating all of the bunches along the focal plane with minimal transverse kicks and bending angle for differing input conditions. The symmetry of the system allows a simple geometric interpretationof the resolving power in terms of thin lenses and ray optics. We discuss the optics and the hardware that is proposed to measure emittance, energy, energy spread and bunch length for each bunch in an RF pulse train for small bunch separations. We also discuss how to use such measurements for feedback and feedforward control of these bunch characteristics as well as maintain their stability. 2 refs

  14. Polarized neutron scattering on HYSPEC: the HYbrid SPECtrometer at SNS

    Energy Technology Data Exchange (ETDEWEB)

    Zaliznyak, Igor [Brookhaven National Laboratory (BNL); Savici, Andrei T [ORNL; Garlea, Vasile O [ORNL; Winn, Barry L [ORNL; Schneelock, John [Brookhaven National Laboratory (BNL); Tranquada, John M. [Brookhaven National Laboratory (BNL); Gu, G. D. [Brookhaven National Laboratory (BNL); Wang, Aifeng [Brookhaven National Laboratory (BNL); Petrovic, C [Brookhaven National Laboratory (BNL)

    2017-01-01

    We describe some of the first polarized neutron scattering measurements performed at HYSPEC spectrometer at the Spallation Neutron Source, Oak Ridge National Laboratory. We discuss details of the instrument setup and the experimental procedures in the mode with the full polarization analysis. Examples of the polarized neutron diffraction and the polarized inelastic neutron data obtained on single crystal samples are presented.

  15. Polarized neutron scattering on HYSPEC: the HYbrid SPECtrometer at SNS

    OpenAIRE

    Zaliznyak, Igor A; Savici, Andrei T.; Garlea, V. Ovidiu; Winn, Barry; Filges, Uwe; Schneeloch, John; Tranquada, John M.; Gu, Genda; Wang, Aifeng; Petrovic, Cedomir

    2016-01-01

    We describe some of the first polarized neutron scattering measurements performed at HYSPEC spectrometer at the Spallation Neutron Source, Oak Ridge National Laboratory. We discuss details of the instrument setup and the experimental procedures in the mode with full polarization analysis. Examples of polarized neutron diffraction and polarized inelastic neutron data obtained on single crystal samples are presented.

  16. Note: A versatile mass spectrometer chamber for molecular beam and temperature programmed desorption experiments

    Energy Technology Data Exchange (ETDEWEB)

    Tonks, James P., E-mail: james.tonks@awe.co.uk [Department of Mechanical Engineering Sciences, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom); AWE Plc, Aldermaston, Reading, Berkshire RG7 4PR (United Kingdom); Galloway, Ewan C., E-mail: ewan.galloway@awe.co.uk; King, Martin O. [AWE Plc, Aldermaston, Reading, Berkshire RG7 4PR (United Kingdom); Kerherve, Gwilherm [VACGEN Ltd, St. Leonards-On-Sea, East Sussex TN38 9NN (United Kingdom); Watts, John F. [Department of Mechanical Engineering Sciences, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom)

    2016-08-15

    A dual purpose mass spectrometer chamber capable of performing molecular beam scattering (MBS) and temperature programmed desorption (TPD) is detailed. Two simple features of this design allow it to perform these techniques. First, the diameter of entrance aperture to the mass spectrometer can be varied to maximize signal for TPD or to maximize angular resolution for MBS. Second, the mass spectrometer chamber can be radially translated so that it can be positioned close to the sample to maximize signal or far from the sample to maximize angular resolution. The performance of this system is described and compares well with systems designed for only one of these techniques.

  17. Large acceptance magnetic spectrometers for polarized deep inelastic electron scattering

    International Nuclear Information System (INIS)

    Petratos, G.G.; Eisele, R.L.; Gearhart, R.A.; Hughes, E.W.; Young, C.C.

    1991-10-01

    The design of two magnetic spectrometers for the measurement of the spin-dependent structure function g 1 n of the neutron and a test of the Bjorken sum rule is described. The measurement will consist of scattering 23 GeV polarized electrons off a polarized 3 He target and detecting scattered electrons of 7 to 18 GeV at 4.5 degree and 7 degree. Each spectrometer is based on two large aperture dipole magnets bending in opposite directions. This ''reverse'' deflection design doubles the solid angle as compared to the conventional design of same direction bends used in previous experiments. Proper choice of the deflection angles and the distance between the two dipoles in each spectrometer allows background photons from radiative processes to reach the detectors only after at least two bounces off the spectrometer vacuum walls, resulting in an expected tolerable background. Each spectrometer is equipped with a pair of Cerenkov detectors, a pair of scintillation hodoscopes and a lead-glass shower calorimeter providing electron and pion identification with angular and momentum resolutions sufficient for the experimental measurement. 7 refs., 8 figs., 1 tab

  18. Scattered radiation in fan beam imaging systems

    International Nuclear Information System (INIS)

    Johns, P.C.; Yaffe, M.

    1982-01-01

    Scatter-to-primary energy fluence ratios (S/P) have been studied for fan x-ray beams as used in CT scanners and slit projection radiography systems. The dependence of S/P on phantom diameter, distance from phantom to image receptor, and kilovoltage is presented. An empirical equation is given that predicts S/P over a wide range of fan beam imaging configurations. For CT body scans on a 4th-generation machine, S/P is approximately 5%. Scattered radiation can produce a significant cupping artefact in CT images which is similar to that due to beam hardening. When multiple slices are used in scanned slit radiography, they can be arranged such that the increase in S/P is negligible. Calculations of scatter-to-primary ratios for first order scattering showed that for fan beams the contribution of coherent scatter is comparable to or greater than that of incoherent first scatter

  19. A new small-angle neutron scattering spectrometer at China Mianyang research reactor

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Mei, E-mail: pm740509@163.com; Sun, Liangwei; Chen, Liang; Sun, Guangai; Chen, Bo; Xie, Chaomei; Xia, Qingzhong; Yan, Guanyun; Tian, Qiang; Huang, Chaoqiang; Pang, Beibei; Zhang, Ying; Wang, Yun; Liu, Yaoguang; Kang, Wu; Gong, Jian

    2016-02-21

    A new pinhole small-angle neutron scattering (SANS) spectrometer, installed at the cold neutron source of the 20 MW China Mianyang Research Reactor (CMRR) in the Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, has been put into use since 2014. The spectrometer is equipped with a multi-blade mechanical velocity selector, a multi-beam collimation system, and a two-dimensional He-3 position sensitive neutron detector. The q-range of the spectrometer covers from 0.01 nm{sup −1} to 5.0 nm{sup −1}. In this paper, the design and characteristics of the SANS spectrometer are described. The q-resolution calculations, together with calibration measurements of silver behenate and a dispersion of nearly monodisperse poly-methyl-methacrylate nanoparticles indicate that our SANS spectrometer has a good performance and is now in routine service. - Highlights: • A new SANS spectrometer has been put into use since 2014 in China. • One MBR selector possesses a higher resolution compared with traditional selector is used. • The spectrometer has a good performance and is now in routinely service.

  20. Simulated performance of the in-beam conversion-electron spectrometer, SPICE

    Energy Technology Data Exchange (ETDEWEB)

    Ketelhut, S., E-mail: ketelhut@triumf.ca [TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, Canada V6T 2A3 (Canada); Evitts, L.J.; Garnsworthy, A.B.; Bolton, C.; Ball, G.C.; Churchman, R. [TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, Canada V6T 2A3 (Canada); Dunlop, R. [Department of Physics, University of Guelph, Guelph, Ontario, Canada N1G 2W1 (Canada); Hackman, G.; Henderson, R.; Moukaddam, M. [TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, Canada V6T 2A3 (Canada); Rand, E.T.; Svensson, C.E. [Department of Physics, University of Guelph, Guelph, Ontario, Canada N1G 2W1 (Canada); Witmer, J. [TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, Canada V6T 2A3 (Canada)

    2014-07-01

    The SPICE spectrometer is a new in-beam electron spectrometer designed to operate in conjunction with the TIGRESS HPGe Clover array at TRIUMF-ISAC. The spectrometer consists of a large area, annular, segmented lithium-drifted silicon electron detector shielded from the target by a photon shield. A permanent magnetic lens directs electrons around the photon shield to the detector. Experiments will be performed utilising Coulomb excitation, inelastic-scattering, transfer and fusion–evaporation reactions using stable and radioactive ion beams with suitable heavy-ion detection. Good detection efficiency can be achieved in a large energy range up to 3500 keV electron energy using several magnetic lens designs which are quickly interchangeable. COMSOL and Geant4 simulations have been used to maximise the detection efficiency. In addition, the simulations have guided the design of components to minimise the contributions from various sources of backgrounds.

  1. Fan analyzer of neutron beam polarization on REMUR spectrometer at IBR-2 pulsed reactor

    International Nuclear Information System (INIS)

    Nikitenko, Yu.V.; Ul'yanov, V.A.; Pusenkov, V.M.; Kozhevnikov, S.V.; Jernenkov, K.N.; Pleshanov, N.K.; Peskov, B.G.; Petrenko, A.V.; Proglyado, V.V.; Syromyatnikov, V.G.; Schebetov, A.F.

    2006-01-01

    The new spectrometer of polarized neutrons REMUR has been created and put in operation in the Frank Laboratory of Neutron Physics (JINR, Dubna). The spectrometer is dedicated to investigations of multiplayer structures and surfaces by registering the reflection of polarized neutrons and of the inhomogeneous state of solid matter by measuring the small-angle scattering of polarized neutrons. The spectrometer's working range of neutron wavelengths is 1.5-10 A. The spectrometer is equipped with a linear position-sensitive detector and a focused supermirror polarization analyzer (fan-like polarization analyzer) with a solid angle of neutron detection of 2.2x10 -4 rad. This article describes the design and the principle of operation of the fan analyzer of neutron polarization together with the results of its tests on a polarized neutron beam

  2. A portable Compton spectrometer for clinical X-ray beams in the energy range 20-150 keV

    International Nuclear Information System (INIS)

    Vieira, A.A.; Linke, A.; Yoshimura, E.M.; Terini, R.A.; Herdade, S.B.

    2011-01-01

    Primary beam spectra were obtained for an X-ray industrial equipment (40-150 kV), and for a clinical mammography apparatus (25-35 kV) from beams scattered at angles close to 90 o , measured with a CdTe Compton spectrometer. Actual scattering angles were determined from the Compton energy shift of characteristic X-rays or spectra end-point energy. Evaluated contribution of coherent scattering amounts to more than 15% of fluence in mammographic beams. This technique can be used in clinical environments.

  3. Omega spectrometer ready for SPS beams

    CERN Multimedia

    CERN PhotoLab

    1977-01-01

    Two different beams arrive into the Omega magnet: - a tagged photon beam for a charm search - experiment WA4 by the Bonn-CERN-Daresbury-Ecole Polytechnique-Glasgow-Lancaster-Manchester-Orsay-Sheffield Collaboration; - a separated hadron beam, at first for a beam-dump experiment - WA12 by the Birmingham-CERN-Ecole Polytechnique-MPI, Munich-Neuchâtel Collaboration. Beams of either negative or positive pions or kaons, protons or antiprotons, all at an energy around 40 GeV were made to impinge on a copper target where a shower of hadrons was produced and, on occasion, two muons which before detection passed through an iron absorber (not visible here). WA12 was completed in February 1977. At the centre, on top of the superconducting magnet, the hut containing the TV cameras, These observe the particle events occurring in the spark chambers in the magnet below.

  4. Small angle neutron scattering using a triple axis spectrometer

    International Nuclear Information System (INIS)

    Ahmed, F.U.; Goyal, P.S.; Kamal, L.; Yunus, S.M.; Datta, T.K.; Rahman, M.O.; Azad, A.K.; Begum, S.; Zakaria, A.K.

    1994-01-01

    SANS techniques has been developed on a triple axis neutron spectrometer at TRIGA Mark II (3 MW) research reactor, AERE, Savar, Dhaka, Bangladesh. Double crystal (with very small mosaic spread ∼ 1 min.) diffraction known as Bonse and Hart's method has been employed. Such a device is a useful tool for small angle scattering in the Q range between 10 -5 and 10 -1 Angstroms -1 and for real time experiments at short time scales. Therefore, large objects and large distance interparticle correlations can be easily investigated. The results of SANS' measurements using alumina (A1 2 0 3 ) sample are presented. The radius of gyration has been determined and the data has been fitted to the scattering function of a sphere. 9 refs., 6 figs.,

  5. A new gradient monochromator for the IN13 back-scattering spectrometer

    International Nuclear Information System (INIS)

    Ciampolini, L.; Bove, L.E.; Mondelli, C.; Alianelli, L.; Labbe-Lavigne, S.; Natali, F.; Bee, M.; Deriu, A.

    2005-01-01

    We present new McStas simulations of the back-scattering thermal neutron spectrometer IN13 to evaluate the advantages of a new temperature gradient monochromator relative to a conventional one. The simulations show that a flux gain up to a factor 7 can be obtained with just a 10% loss in energy resolution and a 20% increase in beam spot size at the sample. The results also indicate that a moderate applied temperature gradient (ΔT∼16K) is sufficient to obtain this significant flux gain. n

  6. Simulation of ion beam scattering in a gas stripper

    Energy Technology Data Exchange (ETDEWEB)

    Maxeiner, Sascha, E-mail: maxeiner@phys.ethz.ch; Suter, Martin; Christl, Marcus; Synal, Hans-Arno

    2015-10-15

    Ion beam scattering in the gas stripper of an accelerator mass spectrometer (AMS) enlarges the beam phase space and broadens its energy distribution. As the size of the injected beam depends on the acceleration voltage through phase space compression, the stripper becomes a limiting factor of the overall system transmission especially for low energy AMS system in the sub MV region. The spatial beam broadening and collisions with the accelerator tube walls are a possible source for machine background and energy loss fluctuations influence the mass resolution and thus isotope separation. To investigate the physical processes responsible for these effects, a computer simulation approach was chosen. Monte Carlo simulation methods are applied to simulate elastic two body scattering processes in screened Coulomb potentials in a (gas) stripper and formulas are derived to correctly determine random collision parameters and free path lengths for arbitrary (and non-homogeneous) gas densities. A simple parametric form for the underlying scattering cross sections is discussed which features important scaling behaviors. An implementation of the simulation was able to correctly model the data gained with the TANDY AMS system at ETH Zurich. The experiment covered transmission measurements of uranium ions in helium and beam profile measurements after the ion beam passed through the He-stripper. Beam profiles measured up to very high stripper densities could be understood in full system simulations including the relevant ion optics. The presented model therefore simulates the fundamental physics of the interaction between an ion beam and a gas stripper reliably. It provides a powerful and flexible tool for optimizing existing AMS stripper geometries and for designing new, state of the art low energy AMS systems.

  7. Beam-transport optimization for cold-neutron spectrometer

    Directory of Open Access Journals (Sweden)

    Nakajima Kenji

    2015-01-01

    Full Text Available We report the design of the beam-transport system (especially the vertical geometry for a cold-neutron disk-chopper spectrometer AMATERAS at J-PARC. Based on the elliptical shape, which is one of the most effective geometries for a ballistic mirror, the design was optimized to obtain, at the sample position, a neutron beam with high flux without serious degrading in divergence and spacial homogeneity within the boundary conditions required from actual spectrometer construction. The optimum focal point was examined. An ideal elliptical shape was modified to reduce its height without serious loss of transmission. The final result was adapted to the construction requirements of AMATERAS. Although the ideas studied in this paper are considered for the AMATERAS case, they can be useful also to other spectrometers in similar situations.

  8. Polarimeters and energy spectrometers for the ILC beam delivery system

    Energy Technology Data Exchange (ETDEWEB)

    Boogert, S. [London Univ. (United Kingdom). Royal Holloway; Hildreth, M. [Univ. of Notre Dame (United States); Kaefer, K. [DESY, Hamburg (Germany); DESY, Zeuthen (DE)] (and others)

    2009-02-15

    This article gives an overview of current plans and issues for polarimeters and energy spectrometers in the Beam Delivery System of the ILC. It is meant to serve as a useful reference for the Detector Letter of Intent documents currently being prepared. (orig.)

  9. Experimental study of the molecular beam destruction by beam-beam and beam-background scattering

    International Nuclear Information System (INIS)

    Bossel, U.; Dettleff, G.

    1974-01-01

    The extraction of flow properties related to the molecular motion normal to stream lines of an expanding gas jet from observed intensity profiles of supersonic beams is critically assessed. The perturbation of the profile curves by various effects is studied for a helium beam. Exponential laws appear to describe scattering effects to a satisfactory degree

  10. Time-of-flight small-angle scattering spectrometers on pulsed neutron sources

    International Nuclear Information System (INIS)

    Ostanevich, Yu.M.

    1987-01-01

    The operation principles, constructions, advantages and shortcomings of known time-of-flight small angle neutron scattering (TOF SANS) spectrometers built up with pulsed neutron sources are reviewed. The most important characteristics of TOF SANS apparatuses are rather a high luminosity and the possibility for the measurement in an extremely wide range of scattering vector at a single exposure. This is achieved by simultaneous employment of white beam, TOF technique for wave length-scan and the commonly known angle-scan. However, the electronic equipment, data-matching programs, and the measurement procedure, necessary for accurate normalization of experimental data and their transformation into absolute cross-section scale, they all become more complex, as compared with those for SANS apparatuses operating on steady-state neutron sources, where only angle-scan is used

  11. 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

  12. Mass-spectrometer MASHA - testing results on heavy ion beam

    International Nuclear Information System (INIS)

    Rodin, A.M.; Belozerov, A.V.; Vanin, D.V.; Dmitriev, S.N.; Itkis, M.G.; Kliman, J.; Krupa, L.; Lebedev, A.N.; Oganesyan, Yu.Ts.; Salamatin, V.S.; Sivachek, I.; Chernysheva, E.V.; Yukhimchuk, S.A.

    2011-01-01

    Description of mass-spectrometer MASHA, developed for the mass identification of superheavy elements, is given. The efficiency and operation speed in the off-line mode were measured with four calibrated leakages of noble gases. The total efficiency and operation speed of mass-spectrometer with hot catcher and ECR ion source were determined using the 40 Ar beam. The test experiment was carried out by measuring the alpha decay of Hg and Rn isotopes, produced in fusion reactions 40 Ar+ nat Sm→ nat-xn Hg+xn and 40 Ar+ 166 Er→ 206-xn Rn+xn, in the focal plane of mass-spectrometer. The operation speed of the given technique and relative yields of isotopes in the test reactions were determined

  13. 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.

  14. Ion beam alignment in the MSX-4 mass spectrometer

    International Nuclear Information System (INIS)

    Busygin, A.I.; Nevzorov, A.A.; Ul'masbaev, B.Sh.

    1977-01-01

    A method for electrically adjusting an ion beam in an MSKh-4 mass-spectrometer has been developed. The adjusting system consists of two deflecting plates fastened to the frame of the ion source. By adjusting the potential difference at the plates in the range 0-150 v, one can increase the intensity of the mass-spectrum by a factor of 3 to 5

  15. The spectrometer of the High-Resolution Multi position Thomson Scattering Diagnostic for TJ-II

    International Nuclear Information System (INIS)

    Herranz, J.; Barth, C. J.; Castejon, F.; Lopez-Sanchez, A.; Mirones, E.; Pastor, I.; Perez, D.; Rodriguez, C.

    2001-01-01

    Since 1998, a high-resolution multiposition thompson scattering system is in operation at the stellarator TJ-II, combining high accuracy and excellent spatial resolution. A description of the diagnostic spectrometer is presented. The main characteristics of the spectrometer that allow YJ-II Thomson scattering diagnostic to have high spatial and spectral resolution are described in this paper. (Author)

  16. Characterisation of neutron beam and gamma spectrometer for PGAA

    International Nuclear Information System (INIS)

    Revay, Zs.; Molnar, G.L.

    2001-01-01

    In the second project year great efforts have been devoted in Budapest to the development of methods and procedures for neutron beam characterisation and spectrometer calibration. These are described here to provide recipes for other laboratories. Some illustrative results obtained on the former thermal guide, and partly on the new cold neutron guide are also given. Preliminary results from the benchmark experiments on flux monitors titanium standard and an unknown sample are also reported. New k o factors for elements of highest priority will be measured on the cold beam only in the near future. (author)

  17. Rotating double arm spectrometer to study hard scattering interactions at Serpukhov accelerator

    International Nuclear Information System (INIS)

    Abramov, V.V.; Baldin, B.Yu.; Buzulutskov, A.F.

    1991-01-01

    The double arm magnetic spectrometer designed to study high P T particle production with intense proton and pion beams is described. Particle trajectories are measured by the drift and proportional chambers. Particles are identified by Cherenkov ring spectrometer and muon identifier. The spectrometer can be rotated around the target up to 160 mrad. 2 tabs.; 13 figs

  18. Permanent-magnet energy spectrometer for electron beams from radiotherapy accelerators

    Energy Technology Data Exchange (ETDEWEB)

    McLaughlin, David J.; Shikhaliev, Polad M.; Matthews, Kenneth L. [Department of Physics and Astronomy, Louisiana State University, 202 Nicholson Hall, Baton Rouge, Louisiana 70803-4001 (United States); Hogstrom, Kenneth R., E-mail: hogstrom@lsu.edu; Carver, Robert L.; Gibbons, John P. [Mary Bird Perkins Cancer Center, 4950 Essen Lane, Baton Rouge, Louisiana 70809-3482 and Department of Physics and Astronomy, Louisiana State University, 202 Nicholson Hall, Baton Rouge, Louisiana 70803-4001 (United States); Clarke, Taylor; Henderson, Alexander; Liang, Edison P. [Physics and Astronomy Department, Rice University, 6100 Main MS-61, Houston, Texas 77005-1827 (United States)

    2015-09-15

    Purpose: The purpose of this work was to adapt a lightweight, permanent magnet electron energy spectrometer for the measurement of energy spectra of therapeutic electron beams. Methods: An irradiation geometry and measurement technique were developed for an approximately 0.54-T, permanent dipole magnet spectrometer to produce suitable latent images on computed radiography (CR) phosphor strips. Dual-pinhole electron collimators created a 0.318-cm diameter, approximately parallel beam incident on the spectrometer and an appropriate dose rate at the image plane (CR strip location). X-ray background in the latent image, reduced by a 7.62-cm thick lead block between the pinhole collimators, was removed using a fitting technique. Theoretical energy-dependent detector response functions (DRFs) were used in an iterative technique to transform CR strip net mean dose profiles into energy spectra on central axis at the entrance to the spectrometer. These spectra were transformed to spectra at 95-cm source to collimator distance (SCD) by correcting for the energy dependence of electron scatter. The spectrometer was calibrated by comparing peak mean positions in the net mean dose profiles, initially to peak mean energies determined from the practical range of central-axis percent depth-dose (%DD) curves, and then to peak mean energies that accounted for how the collimation modified the energy spectra (recalibration). The utility of the spectrometer was demonstrated by measuring the energy spectra for the seven electron beams (7–20 MeV) of an Elekta Infinity radiotherapy accelerator. Results: Plots of DRF illustrated their dependence on energy and position in the imaging plane. Approximately 15 iterations solved for the energy spectra at the spectrometer entrance from the measured net mean dose profiles. Transforming those spectra into ones at 95-cm SCD increased the low energy tail of the spectra, while correspondingly decreasing the peaks and shifting them to slightly lower

  19. Permanent-magnet energy spectrometer for electron beams from radiotherapy accelerators.

    Science.gov (United States)

    McLaughlin, David J; Hogstrom, Kenneth R; Carver, Robert L; Gibbons, John P; Shikhaliev, Polad M; Matthews, Kenneth L; Clarke, Taylor; Henderson, Alexander; Liang, Edison P

    2015-09-01

    The purpose of this work was to adapt a lightweight, permanent magnet electron energy spectrometer for the measurement of energy spectra of therapeutic electron beams. An irradiation geometry and measurement technique were developed for an approximately 0.54-T, permanent dipole magnet spectrometer to produce suitable latent images on computed radiography (CR) phosphor strips. Dual-pinhole electron collimators created a 0.318-cm diameter, approximately parallel beam incident on the spectrometer and an appropriate dose rate at the image plane (CR strip location). X-ray background in the latent image, reduced by a 7.62-cm thick lead block between the pinhole collimators, was removed using a fitting technique. Theoretical energy-dependent detector response functions (DRFs) were used in an iterative technique to transform CR strip net mean dose profiles into energy spectra on central axis at the entrance to the spectrometer. These spectra were transformed to spectra at 95-cm source to collimator distance (SCD) by correcting for the energy dependence of electron scatter. The spectrometer was calibrated by comparing peak mean positions in the net mean dose profiles, initially to peak mean energies determined from the practical range of central-axis percent depth-dose (%DD) curves, and then to peak mean energies that accounted for how the collimation modified the energy spectra (recalibration). The utility of the spectrometer was demonstrated by measuring the energy spectra for the seven electron beams (7-20 MeV) of an Elekta Infinity radiotherapy accelerator. Plots of DRF illustrated their dependence on energy and position in the imaging plane. Approximately 15 iterations solved for the energy spectra at the spectrometer entrance from the measured net mean dose profiles. Transforming those spectra into ones at 95-cm SCD increased the low energy tail of the spectra, while correspondingly decreasing the peaks and shifting them to slightly lower energies. Energy calibration

  20. Bonner sphere spectrometer for characterization of BNCT beam

    Energy Technology Data Exchange (ETDEWEB)

    Marek, Milan, E-mail: mam@nri.cz [Nuclear Research Institute Rez, Husinec 130, 25068 Husinec-Rez (Czech Republic); Viererbl, Ladislav [Nuclear Research Institute Rez, Husinec 130, 25068 Husinec-Rez (Czech Republic)

    2011-12-15

    The characterization of the epithermal beam is performed by different dosimetry techniques that give information on neutron flux as well as neutron and photon doses. One of the possible methods is based on the measurement of thermal neutrons in a moderation environment, which enables the evaluation of neutron flux in a group structure and also neutron dose. The advantage of such a spectrometer consists of the fact that 90% response intervals of the spheres continuously cover the epithermal part of the neutron energy range. The method has been applied to characterize the epithermal neutron beams at several research centers in USA, Finland, the Netherlands and Czech Republic. The comparison of the MIT FCB, HFR HB11, VTT FiR, and LVR-15 beam parameters is presented in this paper.

  1. Emittance growth due to beam-gas scattering

    International Nuclear Information System (INIS)

    Raubenheimer, T.O.

    1992-06-01

    The effect of beam-gas scattering on beam emittance is examined by deriving the beam distribution function. The distribution function is found by treating the beam-gas scattering as a filtered Poisson process and calculating the cumulants of the distribution. (author)

  2. Angular momentum alignment in molecular beam scattering

    International Nuclear Information System (INIS)

    Treffers, M.A.

    1985-01-01

    It is shown how the angular momentum alignment in a molecular beam can be determined using laser-induced fluorescence in combination with precession of the angular momenta in a magnetic field. After a general analysis of the method, some results are presented to illustrate the possibilities of the method. Experimental data are presented on the alignment production for Na 2 molecules that made a collision induced angular momentum transition. Magnitude as well as direction of the alignment have been determined for scattering with several scattering partners and for a large number of scattering angles and transitions. The last chapter deals with the total alignment production in a final J-state, i.e. without state selection of the initial rotational state. (orig.)

  3. Practical guide to the PLUTO small angle scattering spectrometer

    International Nuclear Information System (INIS)

    Page, D.I.

    1980-08-01

    A schematic diagram of the S.A.N.S. instrument is given. Neutrons from a thermal source in the PLUTO reactor pass successively through a cooled beryllium filter, a helical velocity selector and a flight tube with collimating apertures into a specimen chamber. Monitor fission chambers allow measurements of the transmission of the selector and the flux of neutrons incident on the specimen. The neutrons emerging in the forward direction from the specimen enter the detector box where the unscattered ones are stopped by a beam stop and the scattered ones impinge on a 2-dimensional detector which measures their spatial distribution. The output from the detector is fed into a PDP 11/10 computer where the data is collected, manipulated and displayed on a visual display unit. Performance data and practical operating procedure are given. (author)

  4. A data reduction program for the linac total-scattering amorphous materials spectrometer (LINDA)

    International Nuclear Information System (INIS)

    Clarke, J.H.

    1976-01-01

    A computer program has been written to reduce the data collected on the A.E.R.E., Harwell linac total-scattering spectrometer (TSS) to the differential scattering cross-section. This instrument, used for studying the structure of amorphous materials such as liquids and glasses, has been described in detail. Time-of-flight spectra are recorded by several arrays of detectors at different angles using a pulsed incident neutron beam with a continuous distribution of wavelengths. The program performs all necessary background and container subtractions and also absorption corrections using the method of Paalman and Pings. The incident neutron energy distribution is obtained from the intensity recorded from a standard vanadium sample, enabling the observed differential scattering cross-section dsigma/dΩ (theta, lambda) and the structure factor S(Q) to be obtained. Various sample and vanadium geometries can be analysed by the program and facilities exist for the summation of data sets, smoothing of data, application of Placzek corrections and the output of processed data onto magnetic tape or punched cards. A set of example data is provided and some structure factors are shown with absorption corrections. (author)

  5. Multiple-ion-beam time-of-flight mass spectrometer

    International Nuclear Information System (INIS)

    Rohrbacher, Andreas; Continetti, Robert E.

    2001-01-01

    An innovative approach to increase the throughput of mass spectrometric analyses using a multiple-ion-beam mass spectrometer is described. Two sample spots were applied onto a laser desorption/ionization target and each spot was simultaneously irradiated by a beam of quadrupled Nd:YLF laser radiation (261.75 nm) to produce ions by laser-desorption ionization. Acceleration of the ions in an electric field created parallel ion beams that were focused by two parallel einzel lens systems. After a flight path of 2.34 m, the ions were detected with a microchannel plate-phosphor screen assembly coupled with a charge coupled device camera that showed two resolved ion beams. Time-of-flight mass spectra were also obtained with this detector. Experiments were performed using both metal atom cations (Ti + and Cr + ) produced by laser desorption/ionization and the molecular ions of two different proteins (myoglobin and lysozyme), created by matrix assisted laser desorption/ionization using an excess of nicotinic acid as matrix

  6. A fan analyzer of neutron beam polarization on the spectrometer REMUR at the pulsed reactor IBR-2

    International Nuclear Information System (INIS)

    Ul'yanov, V.A.; Pusenkov, V.M.; Pleshanov, N.K.

    2004-01-01

    The new spectrometer of polarized neutrons REMUR has been created and put in operation at the Frank Laboratory of Neutron Physics (JINR, Dubna). The spectrometer is dedicated to investigations of multilayer structures and surfaces by registering the reflection of polarized neutrons and of the inhomogeneous state of solid matter by measuring the small-angle scattering of polarized neutrons. The spectrometer's working range of neutron wavelengths is 1.5-10 Angstroem. The spectrometer is equipped with a linear position-sensitive detector and a focused supermirror polarization analyzer (the fan-like polarization analyzer) with a solid angle of polarized neutron detection of 2.2·10 -4 rad. This paper describes the design and the principle of operation of the fan analyzer of neutron polarization together with the results of the fan tests on a polarized neutron beam

  7. The neutron spin-echo spectrometer: a new high resolution technique in neutron scattering

    International Nuclear Information System (INIS)

    Nicholson, L.K.

    1981-01-01

    The neutron spin-echo (NSE) spectrometer provides the highest energy resolution available in neutron scattering experiments. The article describes the principles behind the first NSE spectrometer (at the Institute Laue-Langevin, Grenoble, France) and, as an example of one of its applications, some recent results on polymer chain dynamics are presented. (author)

  8. Semi-analytical solution to arbitrarily shaped beam scattering

    Science.gov (United States)

    Wang, Wenjie; Zhang, Huayong; Sun, Yufa

    2017-07-01

    Based on the field expansions in terms of appropriate spherical vector wave functions and the method of moments scheme, an exact semi-analytical solution to the scattering of an arbitrarily shaped beam is given. For incidence of a Gaussian beam, zero-order Bessel beam and Hertzian electric dipole radiation, numerical results of the normalized differential scattering cross section are presented to a spheroid and a circular cylinder of finite length, and the scattering properties are analyzed concisely.

  9. Effect of a spectrometer magnet on the beam-beam interaction

    Energy Technology Data Exchange (ETDEWEB)

    Cornacchia, M; Parzen, G

    1981-01-01

    The presence of experimental apparatus in the interaction regions of an intersecting beam accelerator changes the configuration of the crossing beams. This changes the space-charge forces with respect to the standard, magnet-free crossing. The question is: what is the maximum allowable perturbation caused by the spectrometer magnet that can be tolerated from the point of view of the beam dynamics. This paper is limited to the perturbations that the curved trajectories cause the beam-beam space charge nonlinearities. The question has arisen of how one defines the strength of the perturbation. The only solution is to compute the strength of the most important nonlinear resources. In what follows, the computational method used in calculating these resonances is described, and compared with those induced by random orbit errors.

  10. Effect of a spectrometer magnet on the beam-beam interaction

    International Nuclear Information System (INIS)

    Cornacchia, M.; Parzen, G.

    1981-01-01

    The presence of experimental apparatus in the interaction regions of an intersecting beam accelerator changes the configuration of the crossing beams. This changes the space-charge forces with respect to the standard, magnet-free crossing. The question is: what is the maximum allowable perturbation caused by the spectrometer magnet that can be tolerated from the point of view of the beam dynamics. This paper is limited to the perturbations that the curved trajectories cause the beam-beam space charge nonlinearities. The question has arisen of how one defines the strength of the perturbation. The only solution is to compute the strength of the most important nonlinear resources. In what follows, the computational method used in calculating these resonances is described, and compared with those induced by random orbit errors

  11. The performance of neutron scattering spectrometers at a long-pulse spallation source

    International Nuclear Information System (INIS)

    Pynn, R.

    1997-01-01

    In this document the author considers the performance of a long pulse spallation source for those neutron scattering experiments that are usually performed with a monochromatic beam at a continuous wave (CW) source such as a nuclear reactor. The first conclusion drawn is that comparison of the performance of neutron scattering spectrometers at CW and pulsed sources is simpler for long-pulsed sources than it is for the short-pulse variety. Even though detailed instrument design and assessment will require Monte Carlo simulations (which have already been performed at Los Alamos for SANS and reflectometry), simple arguments are sufficient to assess the approximate performance of spectrometers at an LPSS and to support the contention that a 1 MW long-pulse source can provide attractive performance, especially for instrumentation designed for soft-condensed-matter science. Because coupled moderators can be exploited at such a source, its time average cold flux is equivalent to that of a research reactor with a power of about 15 MW, so only a factor of 4 gain from source pulsing is necessary to obtain performance that is comparable with the ILL. In favorable cases, the gain from pulsing can be even more than this, approaching the limit set by the peak flux, giving about 4 times the performance of the ILL. Because of its low duty factor, an LPSS provides the greatest performance gains for relatively low resolution experiments with cold neutrons. It should thus be considered complementary to short pulse sources which are most effective for high resolution experiments using thermal or epithermal neutrons

  12. Automatically controlled correlation spectrometer with a bounded positron beam

    International Nuclear Information System (INIS)

    Grone, R.

    1991-01-01

    The spectrometer consists of a frame which carries a fixed arm with collimating slits and a pair of scintillator units positioned against each other, and a movable arm which moves in the horizontal plane and also holds collimating slits and two scintillator units positioned against each other. In the centre of the frame is a shielding cover with a chamber housing a slidable positron source. The end of the cover is fitted with a replaceable diaphragm against which a sample holder is positioned. The chamber with a bounded positron beam can be employed to measure a sample at preselected sites and thus gain information concerning various parts of the sample surface and its inhomogeneity. (M.D.). 3 figs

  13. Design and construction of a spectrometer facility and experiment for intermediate energy proton scattering on helium

    International Nuclear Information System (INIS)

    Rolfe, R.M.

    1976-12-01

    The goal of the research was to investigate proton scattering on nuclei at intermediate energies and in particular to investigate proton scattering on helium. A theoretical investigation of the helium nucleus and the nature of the intermediate energy interaction, design and optimization of an energy-loss spectrometer facility for proton-nucleus scattering, and the unique superfluid helium target and experimental design are discussed

  14. Characterisation of the incident beam and current diffraction capabilities on the VESUVIO spectrometer

    Science.gov (United States)

    Romanelli, G.; Krzystyniak, M.; Senesi, R.; Raspino, D.; Boxall, J.; Pooley, D.; Moorby, S.; Schooneveld, E.; Rhodes, N. J.; Andreani, C.; Fernandez-Alonso, F.

    2017-09-01

    The VESUVIO spectrometer at the ISIS pulsed neutron and muon source is a unique instrument amongst those available at neutron facilities. This is the only inverted-geometry neutron spectrometer accessing values of energy and wavevector transfer above tens of eV and {\\mathringA}-1 , respectively, and where deep inelastic neutron scattering experiments are routinely performed. As such, the procedure at the base of the technique has been previously described in an article published by this journal (Mayers and Reiter 2012 Meas. Sci. Technol. 23 045902). The instrument has recently witnessed an upsurge of interest due to a new trend to accommodate, within a single experiment, neutron diffraction and transmission measurements in addition to deep inelastic neutron scattering. This work presents a broader description of the instrument following these recent developments. In particular, we assess the absolute intensity and two-dimensional profile of the incident neutron beam and the capabilities of the backscattering diffraction banks. All results are discussed in the light of recent changes to the moderator viewed by the instrument. We find that VESUVIO has to be considered a high-resolution diffractometer as much as other diffractometers at ISIS, with a resolution as high as 2× 10-3 in backscattering. Also, we describe the extension of the wavelength range of the instrument to include lower neutron energies for diffraction measurements, an upgrade that could be readily applied to other neutron instruments as well.

  15. Intra-beam Scattering Theory and RHIC Experiments

    International Nuclear Information System (INIS)

    Wei, J.; Fedotov, A.; Fischer, W.; Malitsky, N.; Parzen, G.; Qiang, J.

    2005-01-01

    Intra-beam scattering is the leading mechanism limiting the luminosity in heavy-ion storage rings like the Relativistic Heavy Ion Collider (RHIC). The multiple Coulomb scattering among the charged particles causes transverse emittance growth and longitudinal beam de-bunching and beam loss, compromising machine performance during collision. Theoretically, the original theories developed by Piwinski, Bjorken, and Mtingwa only describe the rms beam size growth of an unbounded Gaussian distribution. Equations based on the Fokker-Planck approach are developed to further describe the beam density profile evolution and beam loss. During the 2004 RHIC heavy-ion operation, dedicated IBS experiments were performed to bench-mark the rms beam size growth, beam loss, and profile evolution both for a Gaussian-like and a longitudinal hollow beam. This paper summarizes the IBS theory and discusses the experimental bench-marking results

  16. Scatterings and reactions by means of polarized neutron beam

    International Nuclear Information System (INIS)

    Koori, N.

    1989-01-01

    A high resolution polarized neutron beam should be prepared for nuclear physics, which will be planned with the new ring cyclotron at RCNP. Studies on scatterings and reactions by means of polarized neutron beams are reviewed briefly. Beam lines for polarized neutrons are summarized. An example of high resolution measurements of neutron induced reactions is described. (author)

  17. Neutron beam instruments at Harwell

    International Nuclear Information System (INIS)

    Baston, A.H.; Harris, D.H.C.

    1978-11-01

    A list and brief descriptions are given of the neutron beam facilities for U.K. scientists at Harwell and in academic institutions, available under an agreement between the Science Research Council and AERE (Harwell). The list falls under the following headings: reactor instruments (single crystal diffractometers, powder diffractometers, triple axis spectrometers, time-of-flight cold neutron twin rotor spectrometer, beryllium filter spectrometer, MARX spectrometer, Harwell small-angle scattering spectrometer); LINAC instruments (total scattering spectrometer, back scattering spectrometer, active sample spectrometer, inelastic rotor spectrometer, constant Q spectrometer); ancillary equipment (cryostats, superconducting magnets, electromagnets, furnaces). (U.K.)

  18. Scattering of linearly polarized Bessel beams by dielectric spheres

    Science.gov (United States)

    Shoorian, Hamed

    2017-09-01

    The scattering of a Linearly Polarized Bessel Beam (LPBB) by an isotropic and homogenous dielectric sphere is investigated. Using analytical relation between the cylindrical and the spherical vector wave functions, all the closed- form analytical expressions, in terms of spherical wave-functions expansions, are derived for the scattered field. It is shown that in the case of conical angle of incident Bessel beam is equal to zero, the Linearly Polarized Bessel Beam becomes a plane wave and its scattering coefficients become the same as the expansion coefficients of plane wave in Mie theory. The transverse Cartesian and spherical components of the electric field, scattered by a sphere are shown in the z-plane for different cases, moreover the intensity of the incident Bessel beam and the effects of its conical angle on the scattered field and the field inside the sphere are investigated. To quantitatively study the scattering phenomenon and the variations of the fields inside and outside of the sphere, the scattering and absorption efficiencies are obtained for the scattering of the linearly-polarized Bessel beam, and are compared with those of the plane wave scattering.

  19. Experimental characterization of a prototype secondary spectrometer for vertically scattering multiple energy analysis at cold-neutron triple axis spectrometers

    DEFF Research Database (Denmark)

    Toft-Petersen, Rasmus; Groitl, Felix; Kure, Mathias

    2016-01-01

    A thorough experimental characterization of a multiplexing backend with multiple energy analysis on a cold-neutron triple axis spectrometer (cTAS) is presented. The prototype employs two angular segments (2 theta-segments) each containing five vertically scattering analyzers (energy channels...... to the energy resolution of a standard cTAS. The dispersion relation of the antiferromagnetic excitations in MnF2 has been mapped out by performing constant energy transfer maps. These results show that the tested setup is virtually spurion free. In addition, focusing effects due to (mis...

  20. Molecular beam studies of energy transfer in scattering from crystal surfaces

    International Nuclear Information System (INIS)

    Guthrie, W.L.

    1983-01-01

    The translational energy distributions and angular distributions of D 2 O produced from the reaction of incident D 2 and O 2 on a (111) platinum single crystal surface have been measured through the use of a molecular beam-surface scattering apparatus equipped with a time-of-flight spectrometer. The translation energies were measured over the surface temperature range T/sub s/ = 664 K - 913 K and at scattering angles of 7 0 and 40 0 from the surface normal. The D 2 O translational energy, , was found to be approximately half the equilibrium value over the temperature range examined, with /2k varying from 280 K to 480 K. These results are discussed in terms of a non-equilibrium desorption model. The two-photon ionization spectrometer was built to investigate the internal rotational and vibrational energy distributions of NO scattered from Pt(111) surfaces. The rotational energy distributions were measured over the crystal temperature range of T/sub s/ = 400 K - 1200 K. The translational energy distributions and angular distributions were measured using the time-of-flight spectrometer over the crystal temperature range of 400 K - 110 K and for beam translational energies of 0.046 eV, 0.11 eV and 0.24 eV, so that complete energy exchange information for translation, rotation and vibration is available for this gas-surface system. Significant energy transfer was observed in all three modes

  1. A molecular beam/quadrupole mass spectrometer system with synchronized beam modulation and digital waveform analysis

    Science.gov (United States)

    Pellett, G. L.; Adams, B. R.

    1983-01-01

    A performance evaluation is conducted for a molecular beam/mass spectrometer (MB/MS) system, as applied to a 1-30 torr microwave-discharge flow reactor (MWFR) used in the formation of the methylperoxy radical and a study of its subsequent destruction in the presence or absence of NO(x). The modulated MB/MS system is four-staged and differentially pumped. The results obtained by the MWFR study is illustrative of overall system performance, including digital waveform analysis; significant improvements over previous designs are noted in attainable S/N ratio, detection limit, and accuracy.

  2. Inelastic scattering using the three-axis spectrometer technique

    International Nuclear Information System (INIS)

    Currat, R.

    1999-01-01

    The three-axis technique is a basic neutron scattering technique for inelastic work on single-crystal specimens. There is, at the moment, a fair degree of complementarity between TAS instruments on steady-state sources and TOF instruments on steady-state or pulsed sources. The technique is described, the issue of TAS versus TOF method is discussed, and investigations relating to the resolution functions are presented. (K.A.)

  3. Scattered X-ray beam nondestructive testing

    International Nuclear Information System (INIS)

    Harding, G.; Kosanetzky, J.

    1988-01-01

    X-ray scatter interactions generally dominate the linear attenuation coefficient at the photon energies typical of medical and industrial radiography. Specific advantages of X-ray scatter imaging, including a flexible choice of measurement geometry, direct 3D-imaging capability (tomography) and improved information for material characterization, are illustrated with results from Compton and coherent scatter devices. Applications of a Compton backscatter scanner (ComScan) in the aerospace industry and coherent scatter imaging in security screening are briefly considered [pt

  4. Polarisation analysis of elastic neutron scattering using a filter spectrometer on a pulsed source

    International Nuclear Information System (INIS)

    Mayers, J.; Williams, W.G.

    1981-05-01

    The experimental and theoretical aspects of the polarisation analysis technique in elastic neutron scattering are described. An outline design is presented for a filter polarisation analysis spectrometer on the Rutherford Laboratory Spallation Neutron Source and estimates made of its expected count rates and resolution. (author)

  5. High-resolution compact Johann crystal spectrometer with the Livermore electron beam ion trap

    International Nuclear Information System (INIS)

    Robbins, D.L.; Chen, H.; Beiersdorfer, P.; Faenov, A.Ya.; Pikuz, T.A.; May, M.J.; Dunn, J.; Smith, A.J.

    2004-01-01

    A compact high-resolution (λ/Δλ≅10 000) spherically bent crystal spectrometer in the Johann geometry was recently installed and tested on the Lawrence Livermore National Laboratory SuperEBIT electron beam ion trap. The curvature of the mica (002) crystal grating allows for higher collection efficiency compared to the flat and cylindrically bent crystal spectrometers commonly used on the Livermore electron beam ion traps. The spectrometer's Johann configuration enables orientation of its dispersion plane to be parallel to the electron beam propagation. Used in concert with a crystal spectrometer, whose dispersion plane is perpendicular to the electron beam propagation, the polarization of x-ray emission lines can be measured

  6. DNS: Diffuse scattering neutron time-of-flight spectrometer

    Directory of Open Access Journals (Sweden)

    Yixi Su

    2015-08-01

    Full Text Available DNS is a versatile diffuse scattering instrument with polarisation analysis operated by the Jülich Centre for Neutron Science (JCNS, Forschungszentrum Jülich GmbH, outstation at the Heinz Maier-Leibnitz Zentrum (MLZ. Compact design, a large double-focusing PG monochromator and a highly efficient supermirror-based polarizer provide a polarized neutron flux of about 107 n cm-2 s-1. DNS is used for the studies of highly frustrated spin systems, strongly correlated electrons, emergent functional materials and soft condensed matter.

  7. The use of vanadium as a scattering standard for pulsed source neutron spectrometers

    International Nuclear Information System (INIS)

    Mayers, J.

    1983-06-01

    The Gaussian approximation for multiphonon cross-sections has been used in a calculation of the variation of vanadium cross-sections with incident neutron energy. The results show that vanadium behaves as an elastic scatterer to within a few percent on pulsed neutron spectrometers with incident neutron energies up to 1 eV. There is a calculated anisotropy in the scattering of 8%. It is found that the scattering properties of vanadium at 77K and 293K differ by a maximum of 1% except for neutron energies < 15 meV. (author)

  8. 7Li neutron-induced elastic scattering cross section measurement using a slowing-down spectrometer

    Directory of Open Access Journals (Sweden)

    Heusch M.

    2010-10-01

    Full Text Available A new integral measurement of the 7Li neutron induced elastic scattering cross section was determined in a wide neutron energy range. The measurement was performed on the LPSC-PEREN experimental facility using a heterogeneous graphite-LiF slowing-down time spectrometer coupled with an intense pulsed neutron generator (GENEPI-2. This method allows the measurement of the integral elastic scattering cross section in a slowing-down neutron spectrum. A Bayesian approach coupled to Monte Carlo calculations was applied to extract naturalC, 19F and 7Li elastic scattering cross sections.

  9. Simulation of 200-400 MeV/u "1"2C + "1"2C elastic scattering on SHARAQ spectrometer

    International Nuclear Information System (INIS)

    Yu Lei; Zhang Gaolong; Terashima, S.; Le Xiaoyun; Tanihata, I.

    2015-01-01

    In order to further obtain the information of three-body force (TBF) from 200-400 MeV/u "1"2C + "1"2C elastic scattering, we plan to perform this experiment on a SHARAQ spectrometer. Based on the experimental condition of the Radioactive Ion Beam Factory (RIBF)-SHARAQ facility, a simulation is given to find a compromise between the better energy and angular resolutions, and higher yield by optimizing the target thickness, beam transport mode, beam intensity and angular step. From the simulation, we found that the beam quality mainly limits the improvements of energy and angular resolutions. A beam tracking system as well as a lateral and angular dispersion-matching technique are adopted to reduce the influence of beam quality. According to the two angular settings of SHARAQ as well as the expected cross sections on the basis of the theoretical model, the energy and angular resolutions, and statistical accuracy are estimated. (authors)

  10. Dual scattering foil design for poly-energetic electron beams

    International Nuclear Information System (INIS)

    Kainz, K K; Antolak, J A; Almond, P R; Bloch, C D; Hogstrom, K R

    2005-01-01

    The laser wakefield acceleration (LWFA) mechanism can accelerate electrons to energies within the 6-20 MeV range desired for therapy application. However, the energy spectrum of LWFA-generated electrons is broad, on the order of tens of MeV. Using existing laser technology, the therapeutic beam might require a significant energy spread to achieve clinically acceptable dose rates. The purpose of this work was to test the assumption that a scattering foil system designed for a mono-energetic beam would be suitable for a poly-energetic beam with a significant energy spread. Dual scattering foil systems were designed for mono-energetic beams using an existing analytical formalism based on Gaussian multiple-Coulomb scattering theory. The design criterion was to create a flat beam that would be suitable for fields up to 25 x 25 cm 2 at 100 cm from the primary scattering foil. Radial planar fluence profiles for poly-energetic beams with energy spreads ranging from 0.5 MeV to 6.5 MeV were calculated using two methods: (a) analytically by summing beam profiles for a range of mono-energetic beams through the scattering foil system, and (b) by Monte Carlo using the EGS/BEAM code. The analytic calculations facilitated fine adjustments to the foil design, and the Monte Carlo calculations enabled us to verify the results of the analytic calculation and to determine the phase-space characteristics of the broadened beam. Results showed that the flatness of the scattered beam is fairly insensitive to the width of the input energy spectrum. Also, results showed that dose calculated by the analytical and Monte Carlo methods agreed very well in the central portion of the beam. Outside the useable field area, the differences between the analytical and Monte Carlo results were small but significant, possibly due to the small angle approximation. However, these did not affect the conclusion that a scattering foil system designed for a mono-energetic beam will be suitable for a poly

  11. Q resolution calculation of small angle neutron scattering spectrometer and analysis of form factor

    International Nuclear Information System (INIS)

    Chen Liang; Peng Mei; Wang Yan; Sun Liangwei; Chen Bo

    2011-01-01

    The calculational methods of Small Angle Neutron Scattering (SANS) spectrometer Q resolution function and its correlative Q standard difference were introduced. The effects of Q standard difference were analysed with the geometry lay out of spectrometer and the spread of neutron wavelength. The one dimension Q resolution Gaussian function were analysed. The form factor curve of ideal solid sphere and two different instrument arrangement parameter was convoluted respectively and the different smearing curve of form factor was obtained. The combination of using the Q resolution function to more accurately analysis SANS data. (authors)

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

    International Nuclear Information System (INIS)

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

    2004-01-01

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

  13. Scattered radiation from applicators in clinical electron beams

    International Nuclear Information System (INIS)

    Battum, L J van; Zee, W van der; Huizenga, H

    2003-01-01

    In radiotherapy with high-energy (4-25 MeV) electron beams, scattered radiation from the electron applicator influences the dose distribution in the patient. In most currently available treatment planning systems for radiotherapy this component is not explicitly included and handled only by a slight change of the intensity of the primary beam. The scattered radiation from an applicator changes with the field size and distance from the applicator. The amount of scattered radiation is dependent on the applicator design and on the formation of the electron beam in the treatment head. Electron applicators currently applied in most treatment machines are essentially a set of diaphragms, but still do produce scattered radiation. This paper investigates the present level of scattered dose from electron applicators, and as such provides an extensive set of measured data. The data provided could for instance serve as example input data or benchmark data for advanced treatment planning algorithms which employ a parametrized initial phase space to characterize the clinical electron beam. Central axis depth dose curves of the electron beams have been measured with and without applicators in place, for various applicator sizes and energies, for a Siemens Primus, a Varian 2300 C/D and an Elekta SLi accelerator. Scattered radiation generated by the applicator has been found by subtraction of the central axis depth dose curves, obtained with and without applicator. Scattered radiation from Siemens, Varian and Elekta electron applicators is still significant and cannot be neglected in advanced treatment planning. Scattered radiation at the surface of a water phantom can be as high as 12%. Scattered radiation decreases almost linearly with depth. Scattered radiation from Varian applicators shows clear dependence on beam energy. The Elekta applicators produce less scattered radiation than those of Varian and Siemens, but feature a higher effective angular variance. The scattered

  14. Development of a Raman spectrometer to study surface-enhanced Raman scattering

    International Nuclear Information System (INIS)

    Biswas, Nandita; Chadha, Ridhima; Kapoor, Sudhir; Sarkar, Sisir K.; Mukherjee, Tulsi

    2011-02-01

    Raman spectroscopy is an important tool, which provides enormous information on the vibrational and structural details of materials. This understanding is not only interesting due to its fundamental importance, but also of considerable importance in optoelectronics and device applications of these materials in nanotechnology. In this report, we begin with a brief introduction on the Raman effect and various Raman scattering techniques, followed by a detailed discussion on the development of an instrument with home-built collection optics attachment. This Raman system consists of a pulsed laser excitation source, a sample compartment, collection optics to collect the scattered light, a notch filter to reject the intense laser light, a monochromator to disperse the scattered light and a detector to detect the Raman signal. After calibrating the Raman spectrometer with standard solvents, we present our results on Surface-Enhanced Raman Scattering (SERS) investigations on three different kinds of chemical systems. (author)

  15. Resolution of the VESUVIO spectrometer for High-energy Inelastic Neutron Scattering experiments

    Science.gov (United States)

    Imberti, S.; Andreani, C.; Garbuio, V.; Gorini, G.; Pietropaolo, A.; Senesi, R.; Tardocchi, M.

    2005-11-01

    New perspectives for epithermal neutron spectroscopy have been opened up as a result of the development of the Resonance Detector and its use on inverse geometry time-of-flight spectrometers at spallation sources. A special application of the Resonance Detector is the Very Low Angle Detector Bank (VLAD) for the VESUVIO spectrometer at ISIS, operating in the angular range 1∘500 meV, a regime so far inaccessible to experimental studies on condensed matter systems. The HINS measurements complement the Deep Inelastic Neutron Scattering (DINS) measurements performed on VESUVIO in the high wavevector q(20 Å-11 eV), where the short-time single-particle dynamics can be sampled. This paper will revise the main components of the resolution for HINS measurements of VESUVIO. Instrument performances and examples of applications for neutron scattering processes at high energy and at low wavevector transfer are discussed.

  16. Improved performances of 36 m small-angle neutron scattering spectrometer BATAN in Serpong Indonesia

    International Nuclear Information System (INIS)

    Putra, Edy Giri Rachman; Bharoto; Santoso, Eddy; Ikram, Abarrul

    2009-01-01

    SMARTer, a 36 m small-angle neutron scattering (SANS) spectrometer owned by the National Nuclear Energy Agency of Indonesia (BATAN) was installed at the Neutron Scattering Laboratory (NSL) in Serpong, Indonesia. Lots of works on replacing, upgrading and improving the control system, experimental methods, data collection and reduction in the last two years have been carried out to optimize the performance of SMARTer. Some standard samples such as silver behenate, monodisperse polystyrene nanoparticle, porous silica and block copolymer PS-PEP film were measured for the inter-laboratory comparison.

  17. Wavevector and energy resolution of the polarized diffuse scattering spectrometer D7

    Energy Technology Data Exchange (ETDEWEB)

    Fennell, T., E-mail: tom.fennell@psi.ch [Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Mangin-Thro, L., E-mail: mangin-throl@ill.fr [Institut Laue-Langevin, 71 avenue des Martyrs, CS 20156 - 38042 Grenoble Cedex 9 (France); Mutka, H., E-mail: mutka@ill.fr [Institut Laue-Langevin, 71 avenue des Martyrs, CS 20156 - 38042 Grenoble Cedex 9 (France); Nilsen, G.J., E-mail: goran.nilsen@stfc.ac.uk [ISIS Neutron and Muon Source, Rutherford Appleton Laboratory, Didcot OX11 0QX (United Kingdom); Wildes, A.R., E-mail: wildes@ill.fr [Institut Laue-Langevin, 71 avenue des Martyrs, CS 20156 - 38042 Grenoble Cedex 9 (France)

    2017-06-11

    The instrumental divergence parameters and resolution for the D7 neutron diffuse scattering spectrometer at the Institut Laue-Langevin, France, are presented. The resolution parameters are calibrated against measurements of powders, single crystals, and the incoherent scattering from vanadium. We find that the powder diffraction resolution is well described by the Cagliotti function, the single crystal resolution function can be parameterized using the Cooper-Nathans formalism, and that in time-of-flight mode the energy resolution is consistent with monochromatic focussing.

  18. Application of ion scattering spectrometers for the observation of process of cleaning of surfaces of materials for vacuum vessel

    International Nuclear Information System (INIS)

    Akashi, Ken-ya; Miyahara, Akira; Sagara, Akio.

    1978-01-01

    The impurity gas emitted from the surfaces of vacuum vessels was investigated by using the shadowing effect of the covering atoms. The ion scattering spectrometer used for the experiment consists of an ion source, a test sample, an energy analyzer and an ion detector. The evacuation system comprises a turbomolecular pump, a Ti-sublimation pump and an ion pump. The achieved final gas pressure is 5 x 10 -10 Torr. The ion beam intensity to a sample is 10 micro ampere/cm 2 , and the ion energy is about 1 to 1.5 keV. The quantity of oxygen on the surface of a sample molybdenum was measured in the process of evacuation. The concentration of surface oxygen decreased with the gas pressure of the system. It was found that residual oxygen was observed after the sputter etching with Ar ion impact on the surface. The reason of this residual oxygen was considered. (Kato, T.)

  19. Design Principle of A Small Angle Neutron Scattering Spectrometer. Vol. 2

    Energy Technology Data Exchange (ETDEWEB)

    Ashry, A [Dept. of Physics, Faculty of Education, Ain Shams University, Cairo (Egypt)

    1996-03-01

    The design principle of a small angle neutron scattering (SANS) spectrometer is based on producing monochromatic neutron bursts using two phased rotors. The rotors have a number of slots to achieve the highly available intensity of monoenergetic neutrons at the required resolution. The design principle was applied to improve the performance of the pulsed monochromatic double rotor system at ET-RR-1 to operate as SANS spectrometer. It is shown that for rotors having 19 slots each with radius of curvature 96.8 cm, the intensity gain factor is 13. The proposed SANS spectrometer could cover the neutron wavelength range from 2 A{sup {omicron}} up to 6 A{sup {omicron}} through small angles of scattering from 5 x 10{sup -3} rad. to 0.1 rad. i.e, the scattering wavevector transfer between 0.6 A{sup {omicron}-1} and 0.01 A{sup {omicron}-1}. The maximum neutron flux density on the specimen is 5 x 10{sup 5} n cm{sup -2} s{sup -1}. 8 figs.

  20. Three-beam double stimulated Raman scatterings: Cascading configuration

    Science.gov (United States)

    Rao, B. Jayachander; Cho, Minhaeng

    2018-03-01

    Two-beam stimulated Raman scattering (SRS) has been used in diverse label-free spectroscopy and imaging applications of live cells, biological tissues, and functional materials. Recently, we developed a theoretical framework for the three-beam double SRS processes that involve pump, Stokes, and depletion beams, where the pump-Stokes and pump-depletion SRS processes compete with each other. It was shown that the net Stokes gain signal can be suppressed by increasing the depletion beam intensity. The theoretical prediction has been experimentally confirmed recently. In the previous scheme for a selective suppression of one SRS by making it compete with another SRS, the two SRS processes occur in a parallel manner. However, there is another possibility of three-beam double SRS scheme that can be of use to suppress either Raman gain of the Stokes beam or Raman loss of the pump beam by depleting the Stokes photons with yet another SRS process induced by the pair of Stokes and another (second) Stokes beam. This three-beam double SRS process resembles a cascading energy transfer process from the pump beam to the first Stokes beam (SRS-1) and subsequently from the first Stokes beam to the second Stokes beam (SRS-2). Here, the two stimulated Raman gain-loss processes are associated with two different Raman-active vibrational modes of solute molecule. In the present theory, both the radiation and the molecules are treated quantum mechanically. We then show that the cascading-type three-beam double SRS can be described by coupled differential equations for the photon numbers of the pump and Stokes beams. From the approximate solutions as well as exact numerical calculation results for the coupled differential equations, a possibility of efficiently suppressing the stimulated Raman loss of the pump beam by increasing the second Stokes beam intensity is shown and discussed. To further prove a potential use of this scheme for developing a super-resolution SRS microscopy, we

  1. SWIMS, Sigmund and Winterbon Multiple Scattering of Ion Beams

    International Nuclear Information System (INIS)

    Eyeberger, L.

    1999-01-01

    1 - Description of program or function - SWIMS calculates the angular dispersion of ion beams that undergo small-angle, incoherent multiple scattering by gaseous or solid media. 2 - Method of solution - SWIMS uses the tabulated angular distributions of Sigmund and Winterbon for a Thomas-Fermi screened Coulomb potential. The fraction of the incident beam scattered into a cone defined by the polar angle is computed as a function of that angle for a reduced thickness over the rang of 0.01 to 10

  2. Laser-Compton Scattering as a Potential Electron Beam Monitor

    International Nuclear Information System (INIS)

    Chouffani, K.; Wells, D.; Harmon, F.; Lancaster, G.; Jones, J.

    2002-01-01

    LCS experiments were carried out at the Idaho Accelerator Center (IAC); sharp monochromatic x-ray lines were observed. These are produced using the so-called inverse Compton effect, whereby optical laser photons are collided with a relativistic electron beam. The back-scattered photons are then kinematically boosted to keV x-ray energies. We have first demonstrated these beams using a 20 MeV electron beam collided with a 100 MW, 7 ns Nd; YAG laser. We observed narrow LCS x-ray spectral peaks resulting from the interaction of the electron beam with the Nd; YAG laser second harmonic (532 nm). The LCS x-ray energy lines and energy deviations were measured as a function of the electron beam energy and energy-spread respectively. The results showed good agreement with the predicted valves. LCS could provide an excellent probe of electron beam energy, energy spread, transverse and longitudinal distribution and direction

  3. Stochastic cooling and intra-beam scattering in RHIC

    International Nuclear Information System (INIS)

    Wei, J.

    1993-01-01

    During the storage of the heavy ion beam in the Relativistic Heavy Ion Collider (RHIC), the luminosity deterioration due to beam growth and particle loss caused by intra-beam scattering (IBS) is of primary concern. In this paper, the authors study compensation methods using bunched beam stochastic cooling. With longitudinal and transverse stochastic cooling of 4--8 GHz bandwidth, the longitudinal beam loss resulting from the inadequacy of the rf voltage can be eliminated, and the transverse normalized beam emittance can be confined to about 30π mm·mrad. With such an emittance, the β* at the crossing point can be lowered under 1 meter without exceeding the transverse aperture limit at the focusing triplets. The achievable luminosity can thus be significantly improved

  4. Forming of electron beams from a betatron by foils scatterers

    Energy Technology Data Exchange (ETDEWEB)

    Kozlov, A P; Shishov, V A [N.N. Petrov Research Inst. of Oncology, Leningrad (USSR). Laboratory of High Energics

    1976-12-01

    The technique of forming electron beams by one scattering foil and one compensating foil is discussed. This method provides a means for producing large-size uniform dose distributions with much smaller losses in dose rate as compared with conventional beam forming by ine foil. Moreover, the energy losses involved in this process and the background of concomitant bremsstrahlung are much less. A techinque of calculation to determine approximate parameters of the compensating foils is described.

  5. An EXAFS spectrometer on beam line 10B at the Photon Factory

    International Nuclear Information System (INIS)

    Oyanagi, Hiroyuki; Matsushita, Tadashi; Ito, Masahisa; Kuroda, Haruo.

    1984-03-01

    An EXAFS spectrometer installed on the beam line 10B at the Photon Factory is designed to cover the photon energy between 4 and 30 keV. Utilizing either a channel-cut or two flat silicon crystals as a monochromator, a beam intensity between 10 8 and 10 9 photons/sec is obtained at 9 keV with a resolution of 1 eV. The performance of the spectrometer, such as a signal-to-noise ratio or an energy resolution is demonstrated with examples of K edge absorption spectra of bromine, germanium, gallium arsenide, and zinc selenide. (author)

  6. Simulation and optimization of a new focusing polarizing bender for the diffuse neutrons scattering spectrometer DNS at MLZ

    International Nuclear Information System (INIS)

    Nemkovski, K; Ioffe, A; Su, Y; Babcock, E; Schweika, W; Brückel, Th

    2017-01-01

    We present the concept and the results of the simulations of a new polarizer for the diffuse neutron scattering spectrometer DNS at MLZ. The concept of the polarizer is based on the idea of a bender made from the stack of the silicon wafers with a double-side supermirror polarizing coating and absorbing spacers in between. Owing to its compact design, such a system provides more free space for the arrangement of other instrument components. To reduce activation of the polarizer in the high intensity neutron beam of the DNS spectrometer we plan to use the Fe/Si supermirrors instead of currently used FeCoV/Ti:N ones. Using the VITESS simulation package we have performed simulations for horizontally focusing polarizing benders with different geometries in the combination with the double-focusing crystal monochromator of DNS. Neutron transmission and polarization efficiency as well as the effects of the focusing for convergent conventional C-benders and S-benders have been analyzed both for wedge-like and plane-parallel convergent geometries of the channels. The results of these simulations and the advantages/disadvantages of the various configurations are discussed. (paper)

  7. Simulation and optimization of a new focusing polarizing bender for the diffuse neutrons scattering spectrometer DNS at MLZ

    Science.gov (United States)

    Nemkovski, K.; Ioffe, A.; Su, Y.; Babcock, E.; Schweika, W.; Brückel, Th

    2017-06-01

    We present the concept and the results of the simulations of a new polarizer for the diffuse neutron scattering spectrometer DNS at MLZ. The concept of the polarizer is based on the idea of a bender made from the stack of the silicon wafers with a double-side supermirror polarizing coating and absorbing spacers in between. Owing to its compact design, such a system provides more free space for the arrangement of other instrument components. To reduce activation of the polarizer in the high intensity neutron beam of the DNS spectrometer we plan to use the Fe/Si supermirrors instead of currently used FeCoV/Ti:N ones. Using the VITESS simulation package we have performed simulations for horizontally focusing polarizing benders with different geometries in the combination with the double-focusing crystal monochromator of DNS. Neutron transmission and polarization efficiency as well as the effects of the focusing for convergent conventional C-benders and S-benders have been analyzed both for wedge-like and plane-parallel convergent geometries of the channels. The results of these simulations and the advantages/disadvantages of the various configurations are discussed.

  8. Beam life-time with intrabeam scattering and stochastic cooling

    International Nuclear Information System (INIS)

    Wei, J.; Ruggiero, A.G.

    1991-01-01

    A transport equation has been derived in terms of the longitudinal action variable to describe the time evolution of the longitudinal density distribution of a bunched hadron beam in the presence of intrabeam scattering and stochastic cooling. A computer program has been developed to numerically solve this equation. Both beam loss and bunch-shape evolution have been investigated for the 197 Au 79+ beams during the 10-hour storage in the Relativistic Heavy Ion Collider currently under construction at the Brookhaven National Laboratory. 9 refs., 1 fig

  9. Spectrometer Development in Support of Thomson Scattering Investigations for the Helicon Plasma Experiment (HPX)

    Science.gov (United States)

    Sandri, Eva; Davies, Richard; Azzari, Phil; Frank, John; Frank, Jackson; James, Royce; Hopson, Jordon; Duke-Tinson, Omar; Paolino, Richard; Sherman, Justin; Wright, Erin; Turk, Jeremy

    2016-10-01

    Now that reproducible plasmas have been created on the Helicon Plasma Experiment (HPX) at the Coast Guard Academy Plasma Laboratory (CGAPL), a high-performance spectrometer utilizing volume-phase-holographic (VPH) grating and a charge coupled device (CCD) camera with a range of 380-1090 nm and resolution of 1024x1024 is being assembled. This spectrometer will collect doppler shifted photons created by exciting the plasma with the first harmonic of a 2.5 J Nd:YAG laser at a wavelength of 1064 nm. Direct measurements of the plasma's temperature and density will be determined using HPX's Thomson Scattering (TS) system as a single spatial point diagnostic. TS has the capability of determining plasma properties on short time scales and will be used to create a robust picture of the internal plasma parameters. A prototype spectrometer has been constructed to explore the Andor CCD camera's resolution and sensitivity. Concurrently, through intensive study of the high energy TS system, safety protocols and standard operation procedures (SOP) for the Coast Guard's largest and most powerful Laser have been developed. The current status of the TS SOP, diagnostic development, and the collection optic's spectrometer will be reported. Supported by U.S. DEPS Grant [HEL-JTO] PRWJFY15-16.

  10. Double difference method in deep inelastic neutron scattering on the VESUVIO spectrometer

    International Nuclear Information System (INIS)

    Andreani, C.; Colognesi, D.; Degiorgi, E.; Filabozzi, A.; Nardone, M.; Pace, E.; Pietropaolo, A.; Senesi, R.

    2003-01-01

    The principles of the Double Difference (DD) method, applied to the neutron spectrometer VESUVIO, are discussed. VESUVIO, an inverse geometry spectrometer operating at the ISIS pulsed neutron source in the eV energy region, has been specifically designed to measure the single particle dynamical properties in condensed matter. The width of the nuclear resonance of the absorbing filter, used for the neutron energy analysis, provides the most important contribution to the energy resolution of the inverse geometry instruments. In this paper, the DD method, which is based on a linear combination of two measurements recorded with filter foils of the same resonance material but of different thickness, is shown to improve significantly the instrumental energy resolution, as compared with the Single Difference (SD) method. The asymptotic response functions, derived through Monte-Carlo simulations for polycrystalline Pb and ZrH 2 samples, are analysed in both DD and SD methods, and compared with the experimental ones for Pb sample. The response functions have been modelled for two distinct experimental configurations of the VESUVIO spectrometer, employing 6 Li-glass neutron detectors and NaI γ detectors revealing the γ-ray cascade from the (n,γ) reaction, respectively. The DD method appears to be an effective experimental procedure for Deep Inelastic Neutron Scattering measurements on VESUVIO spectrometer, since it reduces the experimental resolution of the instrument in both 6 Li-glass neutron detector and γ detector configurations

  11. Double difference method in deep inelastic neutron scattering on the VESUVIO spectrometer

    Science.gov (United States)

    Andreani, C.; Colognesi, D.; Degiorgi, E.; Filabozzi, A.; Nardone, M.; Pace, E.; Pietropaolo, A.; Senesi, R.

    2003-02-01

    The principles of the Double Difference (DD) method, applied to the neutron spectrometer VESUVIO, are discussed. VESUVIO, an inverse geometry spectrometer operating at the ISIS pulsed neutron source in the eV energy region, has been specifically designed to measure the single particle dynamical properties in condensed matter. The width of the nuclear resonance of the absorbing filter, used for the neutron energy analysis, provides the most important contribution to the energy resolution of the inverse geometry instruments. In this paper, the DD method, which is based on a linear combination of two measurements recorded with filter foils of the same resonance material but of different thickness, is shown to improve significantly the instrumental energy resolution, as compared with the Single Difference (SD) method. The asymptotic response functions, derived through Monte-Carlo simulations for polycrystalline Pb and ZrH 2 samples, are analysed in both DD and SD methods, and compared with the experimental ones for Pb sample. The response functions have been modelled for two distinct experimental configurations of the VESUVIO spectrometer, employing 6Li-glass neutron detectors and NaI γ detectors revealing the γ-ray cascade from the ( n,γ) reaction, respectively. The DD method appears to be an effective experimental procedure for Deep Inelastic Neutron Scattering measurements on VESUVIO spectrometer, since it reduces the experimental resolution of the instrument in both 6Li-glass neutron detector and γ detector configurations.

  12. Double difference method in deep inelastic neutron scattering on the VESUVIO spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Andreani, C.; Colognesi, D.; Degiorgi, E.; Filabozzi, A.; Nardone, M.; Pace, E.; Pietropaolo, A. E-mail: antonino.pietropaolo@roma2.infn.it; Senesi, R

    2003-02-01

    The principles of the Double Difference (DD) method, applied to the neutron spectrometer VESUVIO, are discussed. VESUVIO, an inverse geometry spectrometer operating at the ISIS pulsed neutron source in the eV energy region, has been specifically designed to measure the single particle dynamical properties in condensed matter. The width of the nuclear resonance of the absorbing filter, used for the neutron energy analysis, provides the most important contribution to the energy resolution of the inverse geometry instruments. In this paper, the DD method, which is based on a linear combination of two measurements recorded with filter foils of the same resonance material but of different thickness, is shown to improve significantly the instrumental energy resolution, as compared with the Single Difference (SD) method. The asymptotic response functions, derived through Monte-Carlo simulations for polycrystalline Pb and ZrH{sub 2} samples, are analysed in both DD and SD methods, and compared with the experimental ones for Pb sample. The response functions have been modelled for two distinct experimental configurations of the VESUVIO spectrometer, employing {sup 6}Li-glass neutron detectors and NaI {gamma} detectors revealing the {gamma}-ray cascade from the (n,{gamma}) reaction, respectively. The DD method appears to be an effective experimental procedure for Deep Inelastic Neutron Scattering measurements on VESUVIO spectrometer, since it reduces the experimental resolution of the instrument in both {sup 6}Li-glass neutron detector and {gamma} detector configurations.

  13. Beam-Beam Interaction, Electron Cloud and Intrabeam Scattering for Proton Super-bunches

    CERN Document Server

    Ruggiero, F; Rumolo, Giovanni; Papaphilippou, Y

    2003-01-01

    Super-bunches are long bunches with a flat longitudinal profile, which could potentially increase the LHC luminosity in a future upgrade. We present example parameters and discuss a variety of issues related to such superbunches, including beam-beam tune shift, tune footprints, crossing schemes, luminosity, intrabeam scattering, and electron cloud. We highlight the benefits, disadvantages and open questions.

  14. Scattered radiation from applicators in clinical electron beams.

    NARCIS (Netherlands)

    Battum, L.J. van; Zee, W. van der; Huizenga, H.

    2003-01-01

    In radiotherapy with high-energy (4-25 MeV) electron beams, scattered radiation from the electron applicator influences the dose distribution in the patient. In most currently available treatment planning systems for radiotherapy this component is not explicitly included and handled only by a slight

  15. Collimator scatter and 2D dosimetry in small proton beams

    NARCIS (Netherlands)

    van Luijk, P.; van 't Veld, A.A.; Zelle, H.D.; Schippers, J.M.

    Monte Carlo simulations have been performed to determine the influence of collimator-scattered protons from a 150 MeV proton beam on the dose distribution behind a collimator. Slit-shaped collimators with apertures between 2 and 20 mm have been simulated. The Monte Carlo code GEANT 3.21 has been

  16. Resolution of the VESUVIO spectrometer for High-energy Inelastic Neutron Scattering experiments

    Energy Technology Data Exchange (ETDEWEB)

    Imberti, S. [Universita degli Studi di Roma Tre, Dipartimento di Fisica ' E.Amaldi' , Rome (Italy) and CNR-INFM, Rome (Italy)]. E-mail: silvia.imberti@roma2.infn.it; Andreani, C. [Universita degli Studi di Roma Tor Vergata, Dipartimento di Fisica, Roma 60133 (Italy); CNR-INFM, Rome (Italy); Garbuio, V. [Universita degli Studi di Roma Tor Vergata, Dipartimento di Fisica, Roma 60133 (Italy); CNR-INFM, Rome (Italy); Gorini, G. [Universita degli Studi di Milano-Bicocca, Dipartimento di Fisica ' G.Occhialini' , Milan (Italy); CNR-INFM, Milan (Italy); Pietropaolo, A. [Universita degli Studi di Roma Tor Vergata, Dipartimento di Fisica, Roma 60133 (Italy); CNR-INFM, Rome (Italy); Senesi, R. [Universita degli Studi di Roma Tor Vergata, Dipartimento di Fisica, Roma 60133 (Italy); CNR-INFM, Rome (Italy); Tardocchi, M. [Universita degli Studi di Milano-Bicocca, Dipartimento di Fisica ' G.Occhialini' , Milan (Italy); CNR-INFM, Milan (Italy)

    2005-11-01

    New perspectives for epithermal neutron spectroscopy have been opened up as a result of the development of the Resonance Detector and its use on inverse geometry time-of-flight spectrometers at spallation sources. A special application of the Resonance Detector is the Very Low Angle Detector Bank (VLAD) for the VESUVIO spectrometer at ISIS, operating in the angular range 1 deg. <2{theta}<5 deg. This equipment allows High-energy Inelastic Neutron Scattering (HINS) measurements to be performed in the (q,{omega}) kinematical region at low wavevector (q<10A{sup -1}) and high energy (unlimited) transfer -bar {omega}>500meV, a regime so far inaccessible to experimental studies on condensed matter systems. The HINS measurements complement the Deep Inelastic Neutron Scattering (DINS) measurements performed on VESUVIO in the high wavevector q(20A{sup -1}1eV), where the short-time single-particle dynamics can be sampled. This paper will revise the main components of the resolution for HINS measurements of VESUVIO. Instrument performances and examples of applications for neutron scattering processes at high energy and at low wavevector transfer are discussed.

  17. Beam shape coefficients of the most general focused Gaussian laser beam for light scattering applications

    International Nuclear Information System (INIS)

    Lock, James A.

    2013-01-01

    The vector wave equation for electromagnetic waves, when subject to a number of constraints corresponding to propagation of a monochromatic beam, reduces to a pair of inhomogeneous differential equations describing the transverse electric and transverse magnetic polarized beam components. These differential equations are solved analytically to obtain the most general focused Gaussian beam to order s 4 , where s is the beam confinement parameter, and various properties of the most general Gaussian beam are then discussed. The radial fields of the most general Gaussian beam are integrated to obtain the on-axis beam shape coefficients of the generalized Lorenz–Mie theory formalism of light scattering. The beam shape coefficients are then compared with those of the localized Gaussian beam model and the Davis–Barton fifth-order symmetrized beam. -- Highlights: ► Derive the differential equation for the most general Gaussian beam. ► Solve the differential equation for the most general Gaussian beam. ► Determine the properties of the most general Gaussian beam. ► Determine the beam shape coefficients of the most general Gaussian beam

  18. Study of the ATLAS MDT spectrometer using high energy CERN combined test beam data

    NARCIS (Netherlands)

    Adorisio, C.; et al., [Unknown; Barisonzi, M.; Bobbink, G.; Boterenbrood, H.; Brouwer, G.; Groenstege, H.; Hart, R.; Konig, A.; Linde, F.; van der Graaf, H.; Vermeulen, J.; Vreeswijk, M.; Werneke, P.

    2009-01-01

    In 2004, a combined system test was performed in the H8 beam line at the CERN SPS with a setup reproducing the geometry of sectors of the ATLAS Muon Spectrometer, formed by three stations of Monitored Drift Tubes (MDT). The full ATLAS analysis chain was used to obtain the results presented in this

  19. The very low angle detector for high-energy inelastic neutron scattering on the VESUVIO spectrometer

    International Nuclear Information System (INIS)

    Perelli Cippo, E.; Gorini, G.; Tardocchi, M.; Pietropaolo, A.; Andreani, C.; Senesi, R.; Rhodes, N.J.; Schooneveld, E.M.

    2008-01-01

    The Very Low Angle Detector (VLAD) bank has been installed on the VESUVIO spectrometer at the ISIS spallation neutron source. The new device allows for high-energy inelastic neutron scattering measurements, at energies above 1 eV, maintaining the wave vector transfer lower than 10A -1 . This opens a still unexplored region of the kinematical (q,ω) space, enabling new and challenging experimental investigations in condensed matter. This paper describes the main instrumental features of the VLAD device, including instrument design, detector response, and calibration procedure

  20. The very low angle detector for high-energy inelastic neutron scattering on the VESUVIO spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Perelli Cippo, E.; Gorini, G.; Tardocchi, M. [Dipartimento di Fisica ' G. Occhialini' , Universita degli Studi di Milano-Bicocca, Piazza della Scienza 3, 20126 Milano (Italy); Pietropaolo, A. [Dipartimento di Fisica ' G. Occhialini' , CNISM-Universita degli Studi di Milano-Bicocca, Piazza della Scienza 3, 20126 Milano (Italy); NAST Center - Nanoscienze-Nanotecnologie-Strumentazione, Universita degli Studi di Roma Tor Vergata, via della Ricerca Scientifica 1, 00133 Roma (Italy)], E-mail: antonino.pietropaolo@mib.infn.it; Andreani, C.; Senesi, R. [Dipartimento di Fisica and Centro NAST - Nanoscienze-Nanotecnologie-Strumentazione, Universita degli Studi di Roma Tor Vergata, via della Ricerca Scientifica 1, 00133 Roma (Italy); Rhodes, N.J.; Schooneveld, E.M. [ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire 0QX OX11 (United Kingdom)

    2008-05-01

    The Very Low Angle Detector (VLAD) bank has been installed on the VESUVIO spectrometer at the ISIS spallation neutron source. The new device allows for high-energy inelastic neutron scattering measurements, at energies above 1 eV, maintaining the wave vector transfer lower than 10A{sup -1}. This opens a still unexplored region of the kinematical (q,{omega}) space, enabling new and challenging experimental investigations in condensed matter. This paper describes the main instrumental features of the VLAD device, including instrument design, detector response, and calibration procedure.

  1. The very low angle detector for high-energy inelastic neutron scattering on the VESUVIO spectrometer

    Science.gov (United States)

    Perelli Cippo, E.; Gorini, G.; Tardocchi, M.; Pietropaolo, A.; Andreani, C.; Senesi, R.; Rhodes, N. J.; Schooneveld, E. M.

    2008-05-01

    The Very Low Angle Detector (VLAD) bank has been installed on the VESUVIO spectrometer at the ISIS spallation neutron source. The new device allows for high-energy inelastic neutron scattering measurements, at energies above 1 eV, maintaining the wave vector transfer lower than 10Å-1. This opens a still unexplored region of the kinematical (q, ω) space, enabling new and challenging experimental investigations in condensed matter. This paper describes the main instrumental features of the VLAD device, including instrument design, detector response, and calibration procedure.

  2. Inelastic neutron scattering experiments with the monochromatic imaging mode of the RITA-II spectrometer

    International Nuclear Information System (INIS)

    Bahl, C.R.H.; Lefmann, K.; Abrahamsen, A.B.; Ronnow, H.M.; Saxild, F.; Jensen, T.B.S.; Udby, L.; Andersen, N.H.; Christensen, N.B.; Jakobsen, H.S.; Larsen, T.; Haefliger, P.S.; Streule, S.; Niedermayer, Ch.

    2006-01-01

    Recently a monochromatic multiple data taking mode has been demonstrated for diffraction experiments using a RITA type cold neutron spectrometer with a multi-bladed analyser and a position-sensitive detector. Here, we show how this mode can be used in combination with a flexible radial collimator to perform real inelastic neutron scattering experiments. We present the results from inelastic powder, single crystal dispersion and single crystal constant energy mapping experiments. The advantages and complications of performing these experiments are discussed along with a comparison between the imaging mode and the traditional monochromatic focussing mode

  3. Inelastic neutron scattering experiments with the monochromatic imaging mode of the RITA-II spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Bahl, C.R.H. [Department of Materials Research, Riso National Laboratory, Building 227, Frederiksborgvej 399, DK-4000 Roskilde (Denmark) and Department of Physics, Technical University of Denmark, DK-2800 Lyngby (Denmark)]. E-mail: christian.bahl@risoe.dk; Lefmann, K. [Department of Materials Research, Riso National Laboratory, Building 227, Frederiksborgvej 399, DK-4000 Roskilde (Denmark)]. E-mail: kim.lefmann@risoe.dk; Abrahamsen, A.B. [Department of Materials Research, Riso National Laboratory, Building 227, Frederiksborgvej 399, DK-4000 Roskilde (Denmark); Ronnow, H.M. [Laboratory for Neutron Scattering, Paul Scherrer Institute, CH-5232 Villigen (Switzerland); Saxild, F. [Department of Materials Research, Riso National Laboratory, Building 227, Frederiksborgvej 399, DK-4000 Roskilde (Denmark); Jensen, T.B.S. [Department of Materials Research, Riso National Laboratory, Building 227, Frederiksborgvej 399, DK-4000 Roskilde (Denmark); Udby, L. [Department of Materials Research, Riso National Laboratory, Building 227, Frederiksborgvej 399, DK-4000 Roskilde (Denmark); Andersen, N.H. [Department of Materials Research, Riso National Laboratory, Building 227, Frederiksborgvej 399, DK-4000 Roskilde (Denmark); Christensen, N.B. [Department of Materials Research, Riso National Laboratory, Building 227, Frederiksborgvej 399, DK-4000 Roskilde (Denmark); Laboratory for Neutron Scattering, Paul Scherrer Institute, CH-5232 Villigen (Switzerland); Jakobsen, H.S. [Niels Bohr Institute for Astronomy, Physics and Geophysics, University of Copenhagen, DK-2100 Copenhagen (Denmark); Larsen, T. [Niels Bohr Institute for Astronomy, Physics and Geophysics, University of Copenhagen, DK-2100 Copenhagen (Denmark); Haefliger, P.S. [Laboratory for Neutron Scattering, Paul Scherrer Institute, CH-5232 Villigen (Switzerland); Streule, S.; Niedermayer, Ch. [Laboratory for Neutron Scattering, Paul Scherrer Institute, CH-5232 Villigen (Switzerland)

    2006-05-15

    Recently a monochromatic multiple data taking mode has been demonstrated for diffraction experiments using a RITA type cold neutron spectrometer with a multi-bladed analyser and a position-sensitive detector. Here, we show how this mode can be used in combination with a flexible radial collimator to perform real inelastic neutron scattering experiments. We present the results from inelastic powder, single crystal dispersion and single crystal constant energy mapping experiments. The advantages and complications of performing these experiments are discussed along with a comparison between the imaging mode and the traditional monochromatic focussing mode.

  4. How to measure energy of LEReC electron beam with magnetic spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Seletskiy, S. [Brookhaven National Laboratory (BNL), Upton, NY (United States)

    2016-04-11

    For successful cooling the energies of RHIC ion beam and LEReC electron beam must be matched with 10-4 accuracy. While the energy of ions will be known with required accuracy, e-beam energy can have as large initial offset as 5%. The final setting of e-beam energy will be performed by observing either Schottky spectrum or recombination signal from debunched ions co-traveling with the e-beam. Yet, to start observing such signals one has to set absolute energy of electron beam with accuracy better than 10-2, preferably better than 5∙10-3. The aim of this exercise is to determine whether and how such accuracy can be reached by utilizing LEReC 180° bend as a spectrometer.

  5. Analysis and implementation of a space resolving spherical crystal spectrometer for x-ray Thomson scattering experiments.

    Science.gov (United States)

    Harding, E C; Ao, T; Bailey, J E; Loisel, G; Sinars, D B; Geissel, M; Rochau, G A; Smith, I C

    2015-04-01

    The application of a space-resolving spectrometer to X-ray Thomson Scattering (XRTS) experiments has the potential to advance the study of warm dense matter. This has motivated the design of a spherical crystal spectrometer, which is a doubly focusing geometry with an overall high sensitivity and the capability of providing high-resolution, space-resolved spectra. A detailed analysis of the image fluence and crystal throughput in this geometry is carried out and analytical estimates of these quantities are presented. This analysis informed the design of a new spectrometer intended for future XRTS experiments on the Z-machine. The new spectrometer collects 6 keV x-rays with a spherically bent Ge (422) crystal and focuses the collected x-rays onto the Rowland circle. The spectrometer was built and then tested with a foam target. The resulting high-quality spectra prove that a spherical spectrometer is a viable diagnostic for XRTS experiments.

  6. Scattering calculation and image reconstruction using elevation-focused beams.

    Science.gov (United States)

    Duncan, David P; Astheimer, Jeffrey P; Waag, Robert C

    2009-05-01

    Pressure scattered by cylindrical and spherical objects with elevation-focused illumination and reception has been analytically calculated, and corresponding cross sections have been reconstructed with a two-dimensional algorithm. Elevation focusing was used to elucidate constraints on quantitative imaging of three-dimensional objects with two-dimensional algorithms. Focused illumination and reception are represented by angular spectra of plane waves that were efficiently computed using a Fourier interpolation method to maintain the same angles for all temporal frequencies. Reconstructions were formed using an eigenfunction method with multiple frequencies, phase compensation, and iteration. The results show that the scattered pressure reduces to a two-dimensional expression, and two-dimensional algorithms are applicable when the region of a three-dimensional object within an elevation-focused beam is approximately constant in elevation. The results also show that energy scattered out of the reception aperture by objects contained within the focused beam can result in the reconstructed values of attenuation slope being greater than true values at the boundary of the object. Reconstructed sound speed images, however, appear to be relatively unaffected by the loss in scattered energy. The broad conclusion that can be drawn from these results is that two-dimensional reconstructions require compensation to account for uncaptured three-dimensional scattering.

  7. Developments on positron scattering experiments including beam production and detection

    International Nuclear Information System (INIS)

    Selim, F.A.; Golovchenko, J.A.

    2001-01-01

    Positron scattering and channeling experiments require high quality (low emittance) beams. A new electrostatic optics system for extracting positrons from a moderator is presented. The system features improved efficiency of focusing and beam transport of moderated positrons emitted with angular spreads up to ± 30 , with good phase space characteristics. The presented optics also provides a high degree of freedom in controlling exit beam trajectories. The system has been installed in the LLNL Pelletron accelerator and showed great enhancement on the beam quality. On the detection side, image plates were used to measure the angular distributions of positrons transmitted through the gold crystals. The measurements demonstrate the advantages of image plates as quantitative position sensitive detectors for positrons. (orig.)

  8. Experimental study of intensive electron beam scattering in melting channel

    International Nuclear Information System (INIS)

    Balagura, V.S.; Kurilko, V.I.; Safronov, B.G.

    1988-01-01

    Multiple scattering of an intensive electron beam at 28 keV energy passing through a melting channel in iron targets is experimentally studied. The dependence of scattering on the melting current value is established. The material density in the channel on the basis of the binary collision method is evaluated. It is shown that these density values are of three orders less than the estimations made on the basis of the data on energy losses of electrons in the channel. 6 refs.; 4 figs

  9. Resolution of the VESUVIO spectrometer for High-energy Inelastic Neutron Scattering experiments

    International Nuclear Information System (INIS)

    Imberti, S.; Andreani, C.; Garbuio, V.; Gorini, G.; Pietropaolo, A.; Senesi, R.; Tardocchi, M.

    2005-01-01

    New perspectives for epithermal neutron spectroscopy have been opened up as a result of the development of the Resonance Detector and its use on inverse geometry time-of-flight spectrometers at spallation sources. A special application of the Resonance Detector is the Very Low Angle Detector Bank (VLAD) for the VESUVIO spectrometer at ISIS, operating in the angular range 1 deg. -1 ) and high energy (unlimited) transfer -bar ω>500meV, a regime so far inaccessible to experimental studies on condensed matter systems. The HINS measurements complement the Deep Inelastic Neutron Scattering (DINS) measurements performed on VESUVIO in the high wavevector q(20A -1 -1 ) and high energy transfer (-bar ω>1eV), where the short-time single-particle dynamics can be sampled. This paper will revise the main components of the resolution for HINS measurements of VESUVIO. Instrument performances and examples of applications for neutron scattering processes at high energy and at low wavevector transfer are discussed

  10. spectrometer

    Directory of Open Access Journals (Sweden)

    J. K. Hedelius

    2016-08-01

    Full Text Available Bruker™ EM27/SUN instruments are commercial mobile solar-viewing near-IR spectrometers. They show promise for expanding the global density of atmospheric column measurements of greenhouse gases and are being marketed for such applications. They have been shown to measure the same variations of atmospheric gases within a day as the high-resolution spectrometers of the Total Carbon Column Observing Network (TCCON. However, there is little known about the long-term precision and uncertainty budgets of EM27/SUN measurements. In this study, which includes a comparison of 186 measurement days spanning 11 months, we note that atmospheric variations of Xgas within a single day are well captured by these low-resolution instruments, but over several months, the measurements drift noticeably. We present comparisons between EM27/SUN instruments and the TCCON using GGG as the retrieval algorithm. In addition, we perform several tests to evaluate the robustness of the performance and determine the largest sources of errors from these spectrometers. We include comparisons of XCO2, XCH4, XCO, and XN2O. Specifically we note EM27/SUN biases for January 2015 of 0.03, 0.75, –0.12, and 2.43 % for XCO2, XCH4, XCO, and XN2O respectively, with 1σ running precisions of 0.08 and 0.06 % for XCO2 and XCH4 from measurements in Pasadena. We also identify significant error caused by nonlinear sensitivity when using an extended spectral range detector used to measure CO and N2O.

  11. Chevron beam dump for ITER edge Thomson scattering system

    International Nuclear Information System (INIS)

    Yatsuka, E.; Hatae, T.; Bassan, M.; Itami, K.; Vayakis, G.

    2013-01-01

    This paper contains the design of the beam dump for the ITER edge Thomson scattering system and mainly concerns its lifetime under the harsh thermal and electromagnetic loads as well as tight space allocation. The lifetime was estimated from the multi-pulse laser-induced damage threshold. In order to extend its lifetime, the structure of the beam dump was optimized. A number of bent sheets aligned parallel in the beam dump form a shape called a chevron which enables it to avoid the concentration of the incident laser pulse energy. The chevron beam dump is expected to withstand thermal loads due to nuclear heating, radiation from the plasma, and numerous incident laser pulses throughout the entire ITER project with a reasonable margin for the peak factor of the beam profile. Structural analysis was also carried out in case of electromagnetic loads during a disruption. Moreover, detailed issues for more accurate assessments of the beam dump's lifetime are clarified. Variation of the bi-directional reflection distribution function (BRDF) due to erosion by or contamination of neutral particles derived from the plasma is one of the most critical issues that needs to be resolved. In this paper, the BRDF was assumed, and the total amount of stray light and the absorbed laser energy profile on the beam dump were evaluated

  12. Chevron beam dump for ITER edge Thomson scattering system

    Energy Technology Data Exchange (ETDEWEB)

    Yatsuka, E.; Hatae, T.; Bassan, M.; Itami, K. [Japan Atomic Energy Agency, 801-1 Mukoyama, Naka, Ibaraki 311-0193 (Japan); Vayakis, G. [ITER Organization, 13115 St Paul Lez Durance Cedex (France)

    2013-10-15

    This paper contains the design of the beam dump for the ITER edge Thomson scattering system and mainly concerns its lifetime under the harsh thermal and electromagnetic loads as well as tight space allocation. The lifetime was estimated from the multi-pulse laser-induced damage threshold. In order to extend its lifetime, the structure of the beam dump was optimized. A number of bent sheets aligned parallel in the beam dump form a shape called a chevron which enables it to avoid the concentration of the incident laser pulse energy. The chevron beam dump is expected to withstand thermal loads due to nuclear heating, radiation from the plasma, and numerous incident laser pulses throughout the entire ITER project with a reasonable margin for the peak factor of the beam profile. Structural analysis was also carried out in case of electromagnetic loads during a disruption. Moreover, detailed issues for more accurate assessments of the beam dump's lifetime are clarified. Variation of the bi-directional reflection distribution function (BRDF) due to erosion by or contamination of neutral particles derived from the plasma is one of the most critical issues that needs to be resolved. In this paper, the BRDF was assumed, and the total amount of stray light and the absorbed laser energy profile on the beam dump were evaluated.

  13. Chevron beam dump for ITER edge Thomson scattering system.

    Science.gov (United States)

    Yatsuka, E; Hatae, T; Vayakis, G; Bassan, M; Itami, K

    2013-10-01

    This paper contains the design of the beam dump for the ITER edge Thomson scattering system and mainly concerns its lifetime under the harsh thermal and electromagnetic loads as well as tight space allocation. The lifetime was estimated from the multi-pulse laser-induced damage threshold. In order to extend its lifetime, the structure of the beam dump was optimized. A number of bent sheets aligned parallel in the beam dump form a shape called a chevron which enables it to avoid the concentration of the incident laser pulse energy. The chevron beam dump is expected to withstand thermal loads due to nuclear heating, radiation from the plasma, and numerous incident laser pulses throughout the entire ITER project with a reasonable margin for the peak factor of the beam profile. Structural analysis was also carried out in case of electromagnetic loads during a disruption. Moreover, detailed issues for more accurate assessments of the beam dump's lifetime are clarified. Variation of the bi-directional reflection distribution function (BRDF) due to erosion by or contamination of neutral particles derived from the plasma is one of the most critical issues that needs to be resolved. In this paper, the BRDF was assumed, and the total amount of stray light and the absorbed laser energy profile on the beam dump were evaluated.

  14. High resolution Thomson Parabola Spectrometer for full spectral capture of multi-species ion beams

    International Nuclear Information System (INIS)

    Alejo, A.; Kar, S.; Ahmed, H.; Doria, D.; Borghesi, M.; Tebartz, A.; Ding, J.; Neumann, N.; Astbury, S.; Carroll, D. C.; Scott, G. G.; Higginson, A.; McKenna, P.; Wagner, F.; Roth, M.

    2016-01-01

    We report on the experimental characterisation of laser-driven ion beams using a Thomson Parabola Spectrometer (TPS) equipped with trapezoidally shaped electric plates, proposed by Gwynne et al. [Rev. Sci. Instrum. 85, 033304 (2014)]. While a pair of extended (30 cm long) electric plates was able to produce a significant increase in the separation between neighbouring ion species at high energies, deploying a trapezoidal design circumvented the spectral clipping at the low energy end of the ion spectra. The shape of the electric plate was chosen carefully considering, for the given spectrometer configuration, the range of detectable ion energies and species. Analytical tracing of the ion parabolas matches closely with the experimental data, which suggests a minimal effect of fringe fields on the escaping ions close to the wedged edge of the electrode. The analytical formulae were derived considering the relativistic correction required for the high energy ions to be characterised using such spectrometer.

  15. High resolution Thomson Parabola Spectrometer for full spectral capture of multi-species ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Alejo, A.; Kar, S., E-mail: s.kar@qub.ac.uk; Ahmed, H.; Doria, D.; Borghesi, M. [Centre for Plasma Physics, School of Mathematics and Physics, Queen’s University Belfast, Belfast BT7 1NN (United Kingdom); Tebartz, A.; Ding, J.; Neumann, N. [Institut für Kernphysik, Technische Universität Darmstadt, Schloßgartenstrasse 9, D-64289 Darmstadt (Germany); Astbury, S.; Carroll, D. C.; Scott, G. G. [Central Laser Facility, Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0QX (United Kingdom); Higginson, A.; McKenna, P. [Department of Physics, SUPA, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Wagner, F. [GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstraße 1, 64291 Darmstadt (Germany); Roth, M. [Institut für Kernphysik, Technische Universität Darmstadt, Schloßgartenstraße 9, D-64289 Darmstadt (Germany)

    2016-08-15

    We report on the experimental characterisation of laser-driven ion beams using a Thomson Parabola Spectrometer (TPS) equipped with trapezoidally shaped electric plates, proposed by Gwynne et al. [Rev. Sci. Instrum. 85, 033304 (2014)]. While a pair of extended (30 cm long) electric plates was able to produce a significant increase in the separation between neighbouring ion species at high energies, deploying a trapezoidal design circumvented the spectral clipping at the low energy end of the ion spectra. The shape of the electric plate was chosen carefully considering, for the given spectrometer configuration, the range of detectable ion energies and species. Analytical tracing of the ion parabolas matches closely with the experimental data, which suggests a minimal effect of fringe fields on the escaping ions close to the wedged edge of the electrode. The analytical formulae were derived considering the relativistic correction required for the high energy ions to be characterised using such spectrometer.

  16. High resolution Thomson Parabola Spectrometer for full spectral capture of multi-species ion beams

    Science.gov (United States)

    Alejo, A.; Kar, S.; Tebartz, A.; Ahmed, H.; Astbury, S.; Carroll, D. C.; Ding, J.; Doria, D.; Higginson, A.; McKenna, P.; Neumann, N.; Scott, G. G.; Wagner, F.; Roth, M.; Borghesi, M.

    2016-08-01

    We report on the experimental characterisation of laser-driven ion beams using a Thomson Parabola Spectrometer (TPS) equipped with trapezoidally shaped electric plates, proposed by Gwynne et al. [Rev. Sci. Instrum. 85, 033304 (2014)]. While a pair of extended (30 cm long) electric plates was able to produce a significant increase in the separation between neighbouring ion species at high energies, deploying a trapezoidal design circumvented the spectral clipping at the low energy end of the ion spectra. The shape of the electric plate was chosen carefully considering, for the given spectrometer configuration, the range of detectable ion energies and species. Analytical tracing of the ion parabolas matches closely with the experimental data, which suggests a minimal effect of fringe fields on the escaping ions close to the wedged edge of the electrode. The analytical formulae were derived considering the relativistic correction required for the high energy ions to be characterised using such spectrometer.

  17. Scattering of a high-order Bessel beam by a spheroidal particle

    Science.gov (United States)

    Han, Lu

    2018-05-01

    Within the framework of generalized Lorenz-Mie theory (GLMT), scattering from a homogeneous spheroidal particle illuminated by a high-order Bessel beam is formulated analytically. The high-order Bessel beam is expanded in terms of spheroidal vector wave functions, where the spheroidal beam shape coefficients (BSCs) are computed conveniently using an intrinsic method. Numerical results concerning scattered field in the far zone are displayed for various parameters of the incident Bessel beam and of the scatter. These results are expected to provide useful insights into the scattering of a Bessel beam by nonspherical particles and particle manipulation applications using Bessel beams.

  18. Molecular beam photoionization and gas-surface scattering

    International Nuclear Information System (INIS)

    Ceyer, S.T.

    1979-09-01

    The energetics of the ethylene ion-molecule reactions was investigated in more detail than previously possible in two body collision experiments by photoionization of the neutral van der Waals ethylene dimer. The stability of the (C 2 H 4 ) + C 2 H 4 ion-molecule collision complex has been determined to be 18.2 +- 0.5 kcal. The highest potential barriers along the reaction coordinate for decomposition of this collision complex into C 4 H 7 + + H and C 3 H 5 + + CH 3 have been determined to be 0 +- 1.5 and 8.7 +- 1.5 kcal. In a similar manner, the energetics of the solvated ethylene dimer ion was investigated by the photoionization of the ethylene trimer. The absolute proton affinity of NH 3 (203.6 +- 1.3 kcal/mole) and the proton solvation energies by more than one NH 3 have been determined by molecular beam photoionization. In addition, the NH 3 + -NH 3 interaction energy (0.79 +- 0.05 eV) was measured by photoionization of the neutral van der Waals dimer. These experiments have shown that photoionization of van der Waals clusters is a very powerful method of determining the energetics of gas phase proton solvation. The scattering of helium atomic beams from a high Miller index platinum surface that exhibits ordered, periodic steps on the atomic scale to probe the effect of atomic steps on the scattering distribution is explored. Rainbow scattering is observed when the step edges are perpendicular to the incident helium atoms. The design, construction and operation of a beam-surface scattering apparatus are described. The first data obtained in this apparatus are presented and the interesting dynamical aspects of the oxidation of D, D 2 and CO are discussed. 75 references

  19. Beam tests of prototype fiber detectors for the H1 forward proton spectrometer

    International Nuclear Information System (INIS)

    Baehr, J.; Hiller, K.; Hoffmann, B.; Luedecke, H.; Menchikov, A.; Nahnhauer, R.; Roloff, H.E.; Tonisch, F.; Voelkert, R.

    1994-07-01

    Different prototypes of fiber detectors with an internal trigger system were tested in a 5 GeV electron beam at DESY. A silicon microstrip telescope was used for an external reference measurement of the beam to study the spatial resolution of the fiber detectors. On average 75% of all crossing electron tracks could be reconstructed with a precision better than 150 μm. These successful methodical investigations led to the installation of similar detectors in the proton beamline 81 m downstream of the central H1-detector at HERA as part of a forward proton spectrometer in spring 1994. (orig.)

  20. Beam tests of prototype fiber detectors for the H1 forward proton spectrometer

    International Nuclear Information System (INIS)

    Baehr, J.; Hiller, K.; Hoffmann, B.; Luedecke, H.; Menchikov, A.; Nahnhauer, R.; Roloff, H.E.; Tonisch, F.; Voelkert, R.

    1995-01-01

    Different prototypes of fiber detectors with an internal trigger system were tested in a 5 GeV electron beam at DESY. A silicon microstrip telescope was used for an external reference measurement of the beam to study the spatial resolution of the fiber detectors. On average 75% of all crossing electron tracks could be reconstructed with a precision better than 150 μm. These successful methodical investigations led to the installation of similar detectors in the proton beamline 81 m downstream of the central H1-detector at HERA as part of a forward proton spectrometer in spring 1994. (orig.)

  1. A Time of flight spectrometer for measurements of double differential neutron scattering cross sections

    International Nuclear Information System (INIS)

    Padron, I.; Dominguez, O.; Sarria, P. Sandin, C.

    1996-01-01

    The time -of-Flight neutron spectrometry technique by associated particle method was improved using a D-T neutron generator at Laboratory of Nuclear Analysis. This technique was implemented for double differential cross section measurements and supported by the IAEA Project CUB/01/005. An stilbene scintillation detector (dia=100 mm, length=50 mm) was used as principal neutron detector detector and was situated outside a hole in the concrete wall. This way the fligth path was extended and the scattered neutron cone accurate collimated throught the 2 m concrete wall. For the associated particle α detection a thin plastic NE-102 scint illator was used, as well as, two scintilation detectors and a long counter for the neutron flux monitoring. In this TOF neutron spectrometer (3.40 m flight path) a 1.7 nseg. temporal resolution was obtained

  2. The performance of neutron scattering spectrometers at a long-pulse spallation source

    International Nuclear Information System (INIS)

    Pynn, R.

    1995-01-01

    The first conclusion the author wants to draw is that comparison of the performance of neutron scattering spectrometers at CW and pulsed sources is simpler for long-pulsed sources than it is for the short-pulse variety. Even though detailed instrument design and assessment will require Monte Carlo simulations (which have already been performed at Los Alamos for SANS and reflectometry), simple arguments are sufficient to assess the approximate performance of spectrometers at an LPSS and to support the contention that a 1 MW long-pulse source can provide attractive performance, especially for instrumentation designed for soft-condensed-matter science. Because coupled moderators can be exploited at such a source, its time average cold flux is equivalent to that of a research reactor with a power of about 15 MW, so only a factor of 4 gain from source pulsing is necessary to obtain performance that is comparable with the ILL. In favorable cases, the gain from pulsing can be even more than this, approaching the limit set by the peak flux, giving about 4 times the performance of the ILL. Because of its low duty factor, an LPSS provides the greatest performance gains for relatively low resolution experiments with cold neutrons. It should thus be considered complementary to short pulse sources which are most effective for high resolution experiments using thermal or epithermal neutrons

  3. Design of microcomputer-based data acquisition system for the time-of-flight ion scattering spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Lo, H; Su, C [National Tsing Hua Univ., Hsinchu (Taiwan). Inst. of Nuclear Engineering

    1981-07-15

    A microcomputer-based data aquisition system used on a time-of-flight ion scattering spectrometer is described. The flight time of 90/sup 0/-scattered ions from target atom determined directly with a 30 MHz crystal-controlled oscillator and its associated circuit. The ion intensity is detected by a channel multiplier, and its output signal pulse is converted from the analog form into digital form by an ADC. Both flight time and ion intensity are stored in the microcomputer.

  4. Design of microcomputer-based data acquisition system for the time-of-flight ion scattering spectrometer

    International Nuclear Information System (INIS)

    Lo, H.; Su, C.

    1981-01-01

    A microcomputer-based data aquisition system used on a time-of-flight ion scattering spectrometer is described. The flight time of 90 0 -scattered ions from target atom determined directly with a 30 MHz crystal-controlled oscillator and its associated circuit. The ion intensity is detected by a channel multiplier, and its output signal pulse is converted from the analog form into digital form by an ADC. Both flight time and ion intensity are stored in the microcomputer. (orig.)

  5. Response matrix of an extended range Bonner sphere spectrometer for the characterization of collimated neutron beams

    International Nuclear Information System (INIS)

    Bedogni, R.; Esposito, A.; Gomez-Ros, J.M.

    2010-01-01

    Accelerator-based neutron beams are becoming popular tools for material testing, radiation hardness and soft errors studies. The characterization of these beams in terms of dosimetric and spectrometric quantities is a challenging task, mainly due to their wide energy interval (from thermal up to hundreds MeV) and, in certain facilities like VESUVIO - ISIS (RAL, UK), to their small dimension (few cm in radius). Extended Range Bonner Sphere Spectrometers (ERBSS) would be a valuable tool, due to their wide energy range, good photon discrimination and possibility to choose among different central detectors according to the intensity, photon component and time structure of the field. Nevertheless, the non-uniform irradiation of the spheres could lead to important systematic errors. With the aim of bringing the advantages of ERBSS into the characterization of collimated beams, a dedicated study was performed using the VESUVIO spallation-based collimated beam at ISIS (Rutherford Appleton Laboratory, Oxford). Here a 3.21 cm radius collimated beam was characterized using a Dysprosium activation foil-based ERBSS whose response matrix was recalculated for this specific beam diameter. Besides the results of the experimental campaign, this paper presents the calculation of the response matrix and its dependence on the beam dimension.

  6. Very large solid angle spectrometer for single arm electron scattering experiments

    International Nuclear Information System (INIS)

    Leconte, P.

    1981-01-01

    Major information about short range behavior of nuclear forces should be obtained through electron scattering experiments at high momentum transfer. Cross sections will be very low as is usually the case in electron scattering. In order to reach them, the solid angle of the detection system will have to be enlarged. Traditional optics cannot give correct answer to the problem. For very large apertures, it is impossible to obtain good focussing properties which provide accurate momentum/position correlation with no dependence on the entrance angles. Furthermore, the experiment will require the measurement of these angles. It means that the final system will be equipped with a complete set of position sensitive detectors able to measure positions and angles of trajectories in both planes. Then, the question arises: is it really necessary to provide good focussing, or more precisely: is it possible to get all the required information without the help of a sophisticated predetermined magnetic optics. We try to answer this question and then to sketch from a new point of view the best spectrometer we could think of

  7. Constant-q data representation in Neutron Compton scattering on the VESUVIO spectrometer

    International Nuclear Information System (INIS)

    Senesi, R.; Pietropaolo, A.; Andreani, C.

    2008-01-01

    Standard data analysis on the VESUVIO spectrometer at ISIS is carried out within the Impulse Approximation framework, making use of the West scaling variable y. The experiments are performed using the time-of-flight technique with the detectors positioned at constant scattering angles. Line shape analysis is routinely performed in the y-scaling framework, using two different (and equivalent) approaches: (1) fitting the parameters of the recoil peaks directly to fixed-angle time-of-flight spectra; (2) transforming the time-of-flight spectra into fixed-angle y spectra, referred to as the Neutron Compton Profiles, and then fitting the line shape parameters. The present work shows that scattering signals from different fixed-angle detectors can be collected and rebinned to obtain Neutron Compton Profiles at constant wave vector transfer, q, allowing for a suitable interpretation of data in terms of the dynamical structure factor, S(q,ω). The current limits of applicability of such a procedure are discussed in terms of the available q-range and relative uncertainties for the VESUVIO experimental set up and of the main approximations involved

  8. CdZnTe γ detector for deep inelastic neutron scattering on the VESUVIO spectrometer

    Science.gov (United States)

    Andreani, C.; D'Angelo, A.; Gorini, G.; Imberti, S.; Pietropaolo, A.; Rhodes, N. J.; Schooneveld, E. M.; Senesi, R.; Tardocchi, M.

    In this paper it is shown that solid-state cadmium-zinc-telluride (CZT) is a promising photon detector for neutron spectroscopy in a wide energy interval, ranging from thermal ( 25 meV) to epithermal ( 70 eV) neutron energies. In the present study two CZT detectors were tested as part of the inverse-geometry neutron spectrometer VESUVIO operating at the ISIS pulsed neutron source. The response of the CZT detector to photon emission from radiative neutron capture in 238U was determined by biparametric measurements of neutron time of flight and photon energy. The scattering response function F(y) from a Pb sample has been derived using both CZT and conventional 6Li-glass scintillator detectors. The former showed both an improved signal to background ratio and higher efficiency as compared to 6Li glass, allowing us to measure F(y) up to the fourth 238U absorption energy (Er=66.02 eV). Due to the small size of CZT detectors, their use is envisaged in arrays, with high spatial resolution, for neutron-scattering studies at high energy (ω>1 eV) and low wavevector (q <10 Å-1) transfers.

  9. CdZnTe γ detector for deep inelastic neutron scattering on the VESUVIO spectrometer

    International Nuclear Information System (INIS)

    Andreani, C.; Pietropaolo, A.; Senesi, R.; D'Angelo, A.; Gorini, G.; Imberti, S.; Tardocchi, M.; Rhodes, N.J.; Schooneveld, E.M.

    2004-01-01

    In this paper it is shown that solid-state cadmium-zinc-telluride (CZT) is a promising photon detector for neutron spectroscopy in a wide energy interval, ranging from thermal (∝25 meV) to epithermal (∝70 eV) neutron energies. In the present study two CZT detectors were tested as part of the inverse-geometry neutron spectrometer VESUVIO operating at the ISIS pulsed neutron source. The response of the CZT detector to photon emission from radiative neutron capture in 238 U was determined by biparametric measurements of neutron time of flight and photon energy. The scattering response function F(y) from a Pb sample has been derived using both CZT and conventional 6 Li-glass scintillator detectors. The former showed both an improved signal to background ratio and higher efficiency as compared to 6 Li glass, allowing us to measure F(y) up to the fourth 238 U absorption energy (E r =66.02 eV). Due to the small size of CZT detectors, their use is envisaged in arrays, with high spatial resolution, for neutron-scattering studies at high energy (ℎω>1 eV) and low wavevector (q -1 ) transfers. (orig.)

  10. Constant-q data representation in Neutron Compton scattering on the VESUVIO spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Senesi, R. [Dipartimento di Fisica, Universita degli Studi di Roma ' Tor Vergata' , Via della Ricerca Scientifica 1, 00133 Roma (Italy); Centro NAST, Nanoscienze and Nanotecnologie and Strumentazione, Universita degli Studi di Roma ' Tor Vergata' , Via della Ricerca Scientifica 1, 00133 Roma (Italy)], E-mail: roberto.senesi@roma2.infn.it; Pietropaolo, A.; Andreani, C. [Dipartimento di Fisica, Universita degli Studi di Roma ' Tor Vergata' , Via della Ricerca Scientifica 1, 00133 Roma (Italy); Centro NAST, Nanoscienze and Nanotecnologie and Strumentazione, Universita degli Studi di Roma ' Tor Vergata' , Via della Ricerca Scientifica 1, 00133 Roma (Italy)

    2008-09-01

    Standard data analysis on the VESUVIO spectrometer at ISIS is carried out within the Impulse Approximation framework, making use of the West scaling variable y. The experiments are performed using the time-of-flight technique with the detectors positioned at constant scattering angles. Line shape analysis is routinely performed in the y-scaling framework, using two different (and equivalent) approaches: (1) fitting the parameters of the recoil peaks directly to fixed-angle time-of-flight spectra; (2) transforming the time-of-flight spectra into fixed-angle y spectra, referred to as the Neutron Compton Profiles, and then fitting the line shape parameters. The present work shows that scattering signals from different fixed-angle detectors can be collected and rebinned to obtain Neutron Compton Profiles at constant wave vector transfer, q, allowing for a suitable interpretation of data in terms of the dynamical structure factor, S(q,{omega}). The current limits of applicability of such a procedure are discussed in terms of the available q-range and relative uncertainties for the VESUVIO experimental set up and of the main approximations involved.

  11. Constant- q data representation in Neutron Compton scattering on the VESUVIO spectrometer

    Science.gov (United States)

    Senesi, R.; Pietropaolo, A.; Andreani, C.

    2008-09-01

    Standard data analysis on the VESUVIO spectrometer at ISIS is carried out within the Impulse Approximation framework, making use of the West scaling variable y. The experiments are performed using the time-of-flight technique with the detectors positioned at constant scattering angles. Line shape analysis is routinely performed in the y-scaling framework, using two different (and equivalent) approaches: (1) fitting the parameters of the recoil peaks directly to fixed-angle time-of-flight spectra; (2) transforming the time-of-flight spectra into fixed-angle y spectra, referred to as the Neutron Compton Profiles, and then fitting the line shape parameters. The present work shows that scattering signals from different fixed-angle detectors can be collected and rebinned to obtain Neutron Compton Profiles at constant wave vector transfer, q, allowing for a suitable interpretation of data in terms of the dynamical structure factor, S(q,ω). The current limits of applicability of such a procedure are discussed in terms of the available q-range and relative uncertainties for the VESUVIO experimental set up and of the main approximations involved.

  12. CdZnTe {gamma} detector for deep inelastic neutron scattering on the VESUVIO spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Andreani, C.; Pietropaolo, A.; Senesi, R. [Dipartimento di Fisica, Universita degli Studi di Roma ' Tor Vergata' , Via della Ricerca Scientifica 1, 00133, Roma (Italy); Istituto Nazionale per la Fisica della Materia, UdR, Tor Vergata (Italy); D' Angelo, A. [Dipartimento di Fisica, Universita degli Studi di Roma ' Tor Vergata' , Via della Ricerca Scientifica 1, 00133, Roma (Italy); Istituto Nazionale di Fisica Nucleare, Sezione, Roma II (Italy); Gorini, G.; Imberti, S.; Tardocchi, M. [Dipartimento di Fisica G. Occhialini, Universita degli Studi di Milano-Bicocca, Piazza della Scienza 3, 20126, Milano (Italy); Istituto Nazionale per la Fisica della Materia, UdR, Milano-Bicocca (Italy); Rhodes, N.J.; Schooneveld, E.M. [Isis Facility, Rutherford Appleton Laboratory, Chilton, Didcot, OX11 0QX, Oxfordshire (United Kingdom)

    2004-03-01

    In this paper it is shown that solid-state cadmium-zinc-telluride (CZT) is a promising photon detector for neutron spectroscopy in a wide energy interval, ranging from thermal ({proportional_to}25 meV) to epithermal ({proportional_to}70 eV) neutron energies. In the present study two CZT detectors were tested as part of the inverse-geometry neutron spectrometer VESUVIO operating at the ISIS pulsed neutron source. The response of the CZT detector to photon emission from radiative neutron capture in {sup 238}U was determined by biparametric measurements of neutron time of flight and photon energy. The scattering response function F(y) from a Pb sample has been derived using both CZT and conventional {sup 6}Li-glass scintillator detectors. The former showed both an improved signal to background ratio and higher efficiency as compared to {sup 6}Li glass, allowing us to measure F(y) up to the fourth {sup 238}U absorption energy (E{sub r}=66.02 eV). Due to the small size of CZT detectors, their use is envisaged in arrays, with high spatial resolution, for neutron-scattering studies at high energy ({Dirac_h}{omega}>1 eV) and low wavevector (q <10 A{sup -1}) transfers. (orig.)

  13. Background radiation in inelastic X-ray scattering and X-ray emission spectroscopy. A study for Johann-type spectrometers

    Science.gov (United States)

    Paredes Mellone, O. A.; Bianco, L. M.; Ceppi, S. A.; Goncalves Honnicke, M.; Stutz, G. E.

    2018-06-01

    A study of the background radiation in inelastic X-ray scattering (IXS) and X-ray emission spectroscopy (XES) based on an analytical model is presented. The calculation model considers spurious radiation originated from elastic and inelastic scattering processes along the beam paths of a Johann-type spectrometer. The dependence of the background radiation intensity on the medium of the beam paths (air and helium), analysed energy and radius of the Rowland circle was studied. The present study shows that both for IXS and XES experiments the background radiation is dominated by spurious radiation owing to scattering processes along the sample-analyser beam path. For IXS experiments the spectral distribution of the main component of the background radiation shows a weak linear dependence on the energy for the most cases. In the case of XES, a strong non-linear behaviour of the background radiation intensity was predicted for energy analysis very close to the backdiffraction condition, with a rapid increase in intensity as the analyser Bragg angle approaches π / 2. The contribution of the analyser-detector beam path is significantly weaker and resembles the spectral distribution of the measured spectra. Present results show that for usual experimental conditions no appreciable structures are introduced by the background radiation into the measured spectra, both in IXS and XES experiments. The usefulness of properly calculating the background profile is demonstrated in a background subtraction procedure for a real experimental situation. The calculation model was able to simulate with high accuracy the energy dependence of the background radiation intensity measured in a particular XES experiment with air beam paths.

  14. Molecular beam scattering from clean surfaces of alkali halides

    International Nuclear Information System (INIS)

    Meyers, J.A.

    1975-01-01

    Molecular beam scattering of light gases from in situ cleaved alkali halide surfaces has been studied as a means of developing molecular beam scattering as a surface characterization tool and as a means of obtaining information about the gas atom-solid surface potential interaction. For 4 He scattering from LiF carried out under improved resolution the main results are: (1) there are four bound states in the surface potential well, as energies of -5.8, -2.2, -0.6 and -0.1 MeV. (2) Most of the structure designated as ''fine structure'' is due either to transitions to these four levels via various small reciprocal lattice vectors or to the opening of diffraction channels. (3) The transitions involving the (01) and (0 anti 1) reciprocal lattice vectors (i.e., the ones nearly perpendicular to the incident wavevector) are strong; as much as 85 percent of the specular intensity may be removed. Transitions via the other small reciprocal lattice vectors are much weaker. (4) The widths of the lines are consistent with the velocity distribution, which has a half-width of about 2 percent. (5) The observed energies agree fairly well with those calculated for a zeta-function potential, but are not consistent with a Morse potential. The preliminary results for 4 He/NaF scattering are that there are three bound-states in the surface potential well and are quite similar to the LiF results. These energies are -5.0, -1.9, and -0.5 MeV. 4 He/NaF selective adsorption also shows ''fine structure'' and a more detailed analysis is called for here

  15. Qualification of a high-efficiency, gated spectrometer for x-ray Thomson scattering on the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Döppner, T.; Kritcher, A. L.; Bachmann, B.; Burns, S.; Hawreliak, J.; House, A.; Landen, O. L.; LePape, S.; Ma, T.; Pak, A.; Swift, D. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Neumayer, P. [Gesellschaft für Schwerionenphysik, 64291 Darmstadt (Germany); Kraus, D. [University of California, Berkeley, California 94720 (United States); Falcone, R. W. [University of California, Berkeley, California 94720 (United States); Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Glenzer, S. H. [SLAC National Accelerator Laboratory, Menlo Park, California 94309 (United States)

    2014-11-15

    We have designed, built, and successfully fielded a highly efficient and gated Bragg crystal spectrometer for x-ray Thomson scattering measurements on the National Ignition Facility (NIF). It utilizes a cylindrically curved Highly Oriented Pyrolytic Graphite crystal. Its spectral range of 7.4–10 keV is optimized for scattering experiments using a Zn He-α x-ray probe at 9.0 keV or Mo K-shell line emission around 18 keV in second diffraction order. The spectrometer has been designed as a diagnostic instrument manipulator-based instrument for the NIF target chamber at the Lawrence Livermore National Laboratory, USA. Here, we report on details of the spectrometer snout, its novel debris shield configuration and an in situ spectral calibration experiment with a Brass foil target, which demonstrated a spectral resolution of E/ΔE = 220 at 9.8 keV.

  16. Ps beam production and scattering from gaseous targets

    International Nuclear Information System (INIS)

    Garner, A.J.; Laricchia, G.; Oezen, A.

    1996-01-01

    We have investigated the conversion of a positron beam into an ortho-Ps beam via charge exchange in gaseous H 2 , He and Ar at energies up to 120 eV and gas pressures up to 14 μmHg. H 2 has been found to be the most efficient converter at energies up to 90 eV. At higher energies, Ar has been found to be the best. Total cross sections of ortho-Ps scattering from H 2 and He have also been measured. A comparison with available theories suggests that electron exchange at lower energies and target inelastic collisions at higher energies are playing a major role in the collisions. (author)

  17. Trial fabrication of a secondary x-ray spectrometer with high energy resolution for use in x-ray resonant inelastic scattering experiments

    International Nuclear Information System (INIS)

    Iwazumi, Toshiaki

    2004-01-01

    An instrument was fabricated for use of x-ray resonant inelastic scattering with high-energy resolution in expectation of finding new physical phenomena in strongly correlated electron systems. In the scattering x-ray spectrometer, an asymmetric Johanson crystal spectrometer, which was deployed in an asymmetric Rowland configuration, was designed, fabricated and assessed. The performance expected theoretically for the Johanson spectrometer was recognized from experiments by use of synchrotron radiation. (Y. Kazumata)

  18. Workshop on CEBAF [Continuous Electron Beam Accelerator Facility] spectrometer magnet design and technology: Proceedings

    International Nuclear Information System (INIS)

    1986-09-01

    The planned experimental program at CEBAF includes high-resolution, large acceptance spectrometers and a large toroidal magnetic, detector. In order to take full advantage of the high quality beam characteristics, the performances required will make these devices quite unique instruments compared to existing facilities in the same energy range. Preliminary designs have shown that such performances can be reached, but key questions concerning design concepts and most appropriate and cost-effective technologies had to be answered before going further with the designs. It was the purpose of the Workshop on CEBAF Spectrometer Magnet Design and Technology, organized by the CEBAF Research and Engineering Divisions, to provide the most complete information about the state-of-the-art tools and techniques in magnet design and construction and to discuss the ones most appropriate to the CEBAF spectrometers. In addition, it is expected that this Workshop will be the staring point for further interactions and collaborations between international magnet experts and the CEBAF staff, during the whole process of designing and building the spectrometers

  19. Development of an electron momentum spectrometer for time-resolved experiments employing nanosecond pulsed electron beam

    Science.gov (United States)

    Tang, Yaguo; Shan, Xu; Liu, Zhaohui; Niu, Shanshan; Wang, Enliang; Chen, Xiangjun

    2018-03-01

    The low count rate of (e, 2e) electron momentum spectroscopy (EMS) has long been a major limitation of its application to the investigation of molecular dynamics. Here we report a new EMS apparatus developed for time-resolved experiments in the nanosecond time scale, in which a double toroidal energy analyzer is utilized to improve the sensitivity of the spectrometer and a nanosecond pulsed electron gun with a repetition rate of 10 kHz is used to obtain an average beam current up to nA. Meanwhile, a picosecond ultraviolet laser with a repetition rate of 5 kHz is introduced to pump the sample target. The time zero is determined by photoionizing the target using a pump laser and monitoring the change of the electron beam current with time delay between the laser pulse and electron pulse, which is influenced by the plasma induced by the photoionization. The performance of the spectrometer is demonstrated by the EMS measurement on argon using a pulsed electron beam, illustrating the potential abilities of the apparatus for investigating the molecular dynamics in excited states when employing the pump-probe scheme.

  20. Hyperthermal K--TeF6 molecular beam scattering

    International Nuclear Information System (INIS)

    Wagner, A.F.; Young, C.E.; Pobo, L.G.; Wexler, S.

    1982-01-01

    Angular distributions of K + product ions from collisions of a beam of hyperthermal K atoms with a cross beam of thermal TeF 6 molecules were determined at 13.7 and 23.7 eV (lab). The angular yields of K atom products from the same system were too low to permit measurement of angular distributions. From the integrated yields, the K + ion/K atom branching ratio was determined to be greater than 10 3 . In addition to the extremely large branching ratio, the differential cross sections exhibited several other unusual characteristics: (a) the lack of small angle scattering, corresponding to virtual absence of covalent scattering, (b) two peaks in the differential cross section with an outer rainbow feature at very large scattering angles (approx.275 eV deg). The observations are unexpected from previous experimental and theoretical studies of electron transfer reactions and from the electronic and structural properties of TeF 6 and TeF - 6 . A simplified dynamics model based on formation of electronically excited TeF - 6 in the initial electron transfer, followed by inner crossings leading to formation of electronically and vibrationally unexcited TeF - 6 or dissociation to TeF - 5 and other ionic products, has been developed which accounts for the experimental results. The model suggests that the observed two peaks in the differential cross section are due to the production of TeF - 6 (inner peak) or TeF - 5 and other ionic dissociation products (outer peak). The model also suggests that the observed branching ratio requires a vertical electron affinity of < or =1.9 eV, much lower than its adiabatic electron affinity of 3.3 eV

  1. TRIUMF-ISAC Gamma-Ray Escape-Suppressed Spectrometer (TIGRESS): a versatile tool for radioactive beam physics

    Science.gov (United States)

    Ball, G. C.; Andreyev, A.; Austin, R. A. E.; Bandyopadhyay, D.; Becker, J. A.; Boston, A. J.; Boston, H. C.; Chen, A.; Churchman, R.; Cifarelli, F.; Cline, D.; Cooper, R. J.; Cross, D. S.; Dashdorj, D.; Demand, G.; Dimmock, M. R.; Drake, T. E.; Finlay, P.; Gagon-Moisan, F.; Gallant, A. T.; Garrett, P. E.; Green, K. L.; Grint, A. N.; Hackman, G.; Harkness, L. J.; Hayes, A. B.; Kanungo, R.; Leach, K. G.; Lee, G.; Maharaj, R.; Martin, J.-P.; Morton, A. C.; Mythili, S.; Nelson, L.; Newman, O.; Nolan, P. J.; Padilla-Rodal, E.; Pearson, C. J.; Phillips, A. A.; Porter-Peden, M.; Ressler, J. J.; Roy, R.; Ruiz, C.; Savajols, H.; Sarazin, F.; Schumaker, M. A.; Scraggs, D. P.; Svensson, C. E.; Waddington, J. C.; Wan, J. M.; Whitbeck, A.; Williams, S. J.; Wong, J.; Wu, C. Y.

    2007-05-01

    TIGRESS is a new generation γ-ray spectrometer designed for use with radioactive beams from ISAC. This paper gives an overview of the project and presents results from the first radioactive beam experiment with TIGRESS, the Coulomb excitation of 20,21Na.

  2. Beam loss due to the aperture limitation resulting from intrabeam scattering

    International Nuclear Information System (INIS)

    Lee, S.Y.

    1984-01-01

    Diffusion equation is used to evaluate the beam loss in the presence of aperture limitation resulting from the intrabeam scattering. We discuss the effect of different boundary conditions. Satisfactory beam intensity can be maintained within the proposed RHIC operation time

  3. Single-particle measurements of bouncing particles and in situ collection efficiency from an airborne aerosol mass spectrometer (AMS) with light-scattering detection

    Science.gov (United States)

    Liao, Jin; Brock, Charles A.; Murphy, Daniel M.; Sueper, Donna T.; Welti, André; Middlebrook, Ann M.

    2017-10-01

    A light-scattering module was coupled to an airborne, compact time-of-flight aerosol mass spectrometer (LS-AMS) to investigate collection efficiency (CE) while obtaining nonrefractory aerosol chemical composition measurements during the Southeast Nexus (SENEX) campaign. In this instrument, particles scatter light from an internal laser beam and trigger saving individual particle mass spectra. Nearly all of the single-particle data with mass spectra that were triggered by scattered light signals were from particles larger than ˜ 280 nm in vacuum aerodynamic diameter. Over 33 000 particles are characterized as either prompt (27 %), delayed (15 %), or null (58 %), according to the time and intensity of their total mass spectral signals. The particle mass from single-particle spectra is proportional to that derived from the light-scattering diameter (dva-LS) but not to that from the particle time-of-flight (PToF) diameter (dva-MS) from the time of the maximum mass spectral signal. The total mass spectral signal from delayed particles was about 80 % of that from prompt ones for the same dva-LS. Both field and laboratory data indicate that the relative intensities of various ions in the prompt spectra show more fragmentation compared to the delayed spectra. The particles with a delayed mass spectral signal likely bounced off the vaporizer and vaporized later on another surface within the confines of the ionization source. Because delayed particles are detected by the mass spectrometer later than expected from their dva-LS size, they can affect the interpretation of particle size (PToF) mass distributions, especially at larger sizes. The CE, measured by the average number or mass fractions of particles optically detected that had measurable mass spectra, varied significantly (0.2-0.9) in different air masses. The measured CE agreed well with a previous parameterization when CE > 0.5 for acidic particles but was sometimes lower than the minimum parameterized CE of 0.5.

  4. Self-reconstruction of diffraction-free and accelerating laser beams in scattering media

    International Nuclear Information System (INIS)

    Ersoy, T.; Yalizay, B.; Akturk, S.

    2012-01-01

    We experimentally investigate propagation of laser beams with different intensity profiles in highly scattering media. We generate transverse laser amplitude profiles with Gaussian, Bessel and Airy function envelopes. We then propagate these beams through optical phantoms formed with variable density intralipid solutions. At the sample exit, we compare change in maximum intensities, as well as beam profile reconstruction. We show that self-reconstruction properties of Bessel and Airy beams bring about slower decrease in maximum intensity with increasing scatterer density. On the other hand, the beam profiles deteriorate faster, as compared to reference Gaussian beams. Slower decrease in the intensity can be attributed to the wavevector spectra providing a continuous flow of energy to the beam center, while beam deterioration is linked to total beam volume in the scattering medium. These results show that beam shaping methods can significantly enhance delivery of intense light deeper into turbid media, but this enhancement is compromised by stronger speckling of beam profiles. -- Highlights: ► We experimentally investigate propagation of shaped laser beams in turbid media. ► Peak intensity of Bessel and Airy beams decrease slower with increasing scatterer. ► Shaped beam profiles deteriorate faster, as compared to reference Gaussian beams. ► Shaped beam profiles can enhance applications of lasers inscattering media.

  5. In-beam study of {sup 253}No using the SAGE spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Mistry, A.K.; Herzberg, R.D.; Butler, P.A.; Cox, D.M.; Joss, D.T.; Page, R.D.; Seddon, D.; Thornhill, J.; Wells, D. [University of Liverpool, Oliver Lodge Laboratory, Liverpool (United Kingdom); Greenlees, P.T.; Papadakis, P.; Auranen, K.; Grahn, T.; Jakobsson, U.; Julin, R.; Konki, J.; Leino, M.; Pakarinen, J.; Peura, P.; Rahkila, P.; Sandzelius, M.; Scholey, C.; Sorri, J.; Stolze, S.; Uusitalo, J. [University of Jyvaskyla, Department of Physics, Jyvaskyla (Finland); Garnsworthy, A.B.; Ketelhut, S. [University of British Columbia, TRIUMF, Vancouver, British Columbia (Canada); Hauschild, K.; Lopez-Martens, A. [Universite Paris-Sud, CSNSM, CNRS, IN2P3, Orsay (France); Simpson, J. [STFC, Daresbury Laboratory, Daresbury, Warrington (United Kingdom)

    2017-02-15

    The heavy actinide nucleus {sup 253}No (Z = 102) was studied using the (S)ilicon (A)nd (Ge)rmanium (SAGE) spectrometer allowing simultaneous in-beam γ-ray and conversion electron spectroscopy at the accelerator laboratory of the University of Jyvaeskylae. Using the recoil-tagging technique, γ-electron coincidences have allowed for the extension of the level scheme in the lower-spin region of the yrast band. In addition, internal conversion coefficient (ICC) measurements to establish the multipolarity of transitions have been performed. Measurement of the interband-intraband branching ratios supports the assignment of the Nilsson band-head configuration 9/2{sup -}[734] assigned in previous studies. The study shows the viability of combined in-beam electron and γ-ray spectroscopy down to μb cross sections. (orig.)

  6. The XRS microcalorimeter spectrometer at the Livermore Electron Beam Ion Trap

    Energy Technology Data Exchange (ETDEWEB)

    Porter, F S; Beiersdorfer, P; Boyce, K; Brown, G V; Chen, H; Gygax, J; Kahn, S M; Kelley, R; Kilbourne, C A; Magee, E; Thorn, D B

    2007-08-22

    NASA's X-ray Spectrometer (XRS) microcalorimeter instrument has been operating at the Electron Beam Ion Trap (EBIT) facility at Lawrence Livermore National Laboratory since July of 2000. The spectrometer is currently undergoing its third major upgrade to become an easy to use, extremely high performance instrument for a broad range of EBIT experiments. The spectrometer itself is broadband, capable of simultaneously operating from 0.1 to 12 keV and has been operated at up to 100 keV by manipulating its operating conditions. The spectral resolution closely follows the spaceflight version of the XRS, beginning at 10 eV FWHM at 6 keV in 2000, upgraded to 5.5 eV in 2003, and will hopefully be {approx}3.8 eV in the Fall of 2007. Here we review the operating principles of this unique instrument, the extraordinary science that has been performed at EBIT over the last 6 years, and prospects for future upgrades. Specifically we discuss upgrades to cover the high-energy band (to at least 100 keV) with a high quantum efficiency detector, and prospects for using a new superconducting detector to reach 0.8 eV resolution at 1 keV, and 2 eV at 6 keV with high counting rates.

  7. np Elastic-scattering experiments with polarized neutron beams

    International Nuclear Information System (INIS)

    Chalmers, J.S.; Ditzler, W.R.; Hill, D.

    1985-01-01

    Measurements of the spin transfer parameters, K/sub NN/ and K/sub LL/, at 500, 650, and 800 MeV are presented for the reaction p-vector d → n-vector pp at 0 0 . The data are useful input to the NN data base and indicate that the quasi-free charge exchange (CEX) reaction is a useful mechanism for producing neutrons with at least 40% polarization at energies as low as 500 MeV. Measurements of np elastic scattering observables C/sub LL/ and C/sub SL/ covering 35 0 to 172 0 are performed using a polarized neutron beam at 500, 650, and 800 MeV. Preliminary results are presented. 3 refs., 6 figs

  8. Crossed-molecular-beams reactive scattering of oxygen atoms

    International Nuclear Information System (INIS)

    Baseman, R.J.

    1982-11-01

    The reactions of O( 3 P) with six prototypical unsaturated hydrocarbons, and the reaction of O( 1 D) with HD, have been studied in high-resolution crossed-molecular-beams scattering experiments with mass-spectrometric detection. The observed laboratory-product angular and velocity distributions unambiguously identify parent-daughter ion pairs, distinguish different neutral sources of the same ion, and have been used to identify the primary products of the reactions. The derived center-of-mass product angular and translational energy distributions have been used to elucidate the detailed reaction dynamics. These results demonstrate that O( 3 P)-unsaturated hydrocarbon chemistry is dominated by single bond cleavages, leading to radical products exclusively

  9. Crossed-molecular-beams reactive scattering of oxygen atoms

    Energy Technology Data Exchange (ETDEWEB)

    Baseman, R.J.

    1982-11-01

    The reactions of O(/sup 3/P) with six prototypical unsaturated hydrocarbons, and the reaction of O(/sup 1/D) with HD, have been studied in high-resolution crossed-molecular-beams scattering experiments with mass-spectrometric detection. The observed laboratory-product angular and velocity distributions unambiguously identify parent-daughter ion pairs, distinguish different neutral sources of the same ion, and have been used to identify the primary products of the reactions. The derived center-of-mass product angular and translational energy distributions have been used to elucidate the detailed reaction dynamics. These results demonstrate that O(/sup 3/P)-unsaturated hydrocarbon chemistry is dominated by single bond cleavages, leading to radical products exclusively.

  10. Multi-beam Mossbauer scattering facility. Final technical report

    International Nuclear Information System (INIS)

    1994-01-01

    The Mossbauer instrument construction which was financed by the DOE grant of $74,065 and MU matching funds of $52,000 is essentially completed and awaiting installation at the Missouri University Research Reactor (MURR) facility. All of the DOE funds have been spent and all of the matching funds plus about $4,000 to $5,000 of additional physics department funds have been committed to finishing the first phase of the new instrument, QUEGS--II (for QUAsiElastic Gamma-ray Scattering--generation II). This phase includes computer controls, detectors, and instrumentation for two of the four beam lines afforded by QUEGS-II. Included in this commitment of funds is $8,700 for equipment and machine shop services which have not yet been paid and $19,700 for a Ge detector for which bids are ready to be let

  11. One-dimensional theory and simulation of acceleration in relativistic electron beam Raman scattering

    International Nuclear Information System (INIS)

    Abe, T.

    1986-01-01

    Raman scattering by a parallel relativistic electron beam was examined analytically and by using the numerical simulation. Incident wave energy can be transferred not only to the scattered electromagnetic wave but also to the beam. That is, the beam can be accelerated by the Doppler-shifted plasma oscillation accompanied by the scattered wave. The energy conversion rates for them were obtained. They increase with the γ value of the electron beam. For the larger γ values of the beam, the energy of the incident wave is mainly transferred to the beam, while in smaller γ, the energy conversion rate to the scattered wave is about 0.2 times that to the beam. Even in smaller γ, the total energy conversion rate is about 0.1

  12. Mass measurement of halo nuclides and beam cooling with the mass spectrometer Mistral

    International Nuclear Information System (INIS)

    Bachelet, C.

    2004-12-01

    Halo nuclides are a spectacular drip-line phenomenon and their description pushes nuclear theories to their limits. The most critical input parameter is the nuclear binding energy; a quantity that requires excellent measurement precision, since the two-neutron separation energy is small at the drip-line by definition. Moreover halo nuclides are typically very short-lived. Thus, a high accuracy instrument using a quick method of measurement is necessary. MISTRAL is such an instrument; it is a radiofrequency transmission mass spectrometer located at ISOLDE/CERN. In July 2003 we measured the mass of the Li 11 , a two-neutron halo nuclide. Our measurement improves the precision by a factor 6, with an error of 5 keV. Moreover the measurement gives a two-neutron separation energy 20% higher than the previous value. This measurement has an impact on the radius of the nucleus, and on the state of the two valence neutrons. At the same time, a measurement of the Be 11 was performed with an uncertainty of 4 keV, in excellent agreement with previous measurements. In order to measure the mass of the two-neutron halo nuclide Be 14 , an ion beam cooling system is presently under development which will increase the sensitivity of the spectrometer. The second part of this work presents the development of this beam cooler using a gas-filled Paul trap. (author)

  13. LabVIEW control software for scanning micro-beam X-ray fluorescence spectrometer.

    Science.gov (United States)

    Wrobel, Pawel; Czyzycki, Mateusz; Furman, Leszek; Kolasinski, Krzysztof; Lankosz, Marek; Mrenca, Alina; Samek, Lucyna; Wegrzynek, Dariusz

    2012-05-15

    Confocal micro-beam X-ray fluorescence microscope was constructed. The system was assembled from commercially available components - a low power X-ray tube source, polycapillary X-ray optics and silicon drift detector - controlled by an in-house developed LabVIEW software. A video camera coupled to optical microscope was utilized to display the area excited by X-ray beam. The camera image calibration and scan area definition software were also based entirely on LabVIEW code. Presently, the main area of application of the newly constructed spectrometer is 2-dimensional mapping of element distribution in environmental, biological and geological samples with micrometer spatial resolution. The hardware and the developed software can already handle volumetric 3-D confocal scans. In this work, a front panel graphical user interface as well as communication protocols between hardware components were described. Two applications of the spectrometer, to homogeneity testing of titanium layers and to imaging of various types of grains in air particulate matter collected on membrane filters, were presented. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. Beam Diagnostics for Laser Undulator Based on Compton Backward Scattering

    CERN Document Server

    Kuroda, R

    2005-01-01

    A compact soft X-ray source is required in various research fields such as material and biological science. The laser undulator based on Compton backward scattering has been developed as a compact soft X-ray source for the biological observation at Waseda University. It is performed in a water window region (250eV - 500 eV) using the interaction between 1047 nm Nd:YLF laser (10ps FWHM) and about 5 MeV high quality electron beam (10ps FWHM) generated from rf gun system. The range of X-ray energy in the water window region has K-shell absorption edges of Oxygen, Carbon and Nitrogen, which mainly constitute of living body. Since the absorption coefficient of water is much smaller than the protein's coefficient in this range, a dehydration of the specimens is not necessary. To generate the soft X-ray pulse stably, the electron beam diagnostics have been developed such as the emittance measurement using double slit scan technique, the bunch length measurement using two frequency analysis technique. In this confere...

  15. Spectrometer for Particle Characterization With a New Multiple-Scattering Theory, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — There are two major commercial types of light-scattering particle size analyzers: Static Light Scattering and Dynamic Light Scattering. They are expensive, delicate,...

  16. Effect of the selective adsorption on the reactive scattering process of molecular beams from stepped surfaces

    International Nuclear Information System (INIS)

    Garcia, N.

    1977-01-01

    An indicative proposal which may explain the diffusion of incident atomic beams scattered by a crystal surface is made in terms of the selective adsorption mechanism. In this sense, the stepped metallic surfaces present characteristics which enhance the displacements and the lifetimes of the beams on the surface. This may be important for increasing the exchange reactive scattering of molecules from crystal surfaces

  17. Scattering of thermal photons by a 46 GeV positron beam at LEP

    International Nuclear Information System (INIS)

    Bini, C.; De Zorzi, G.; Diambrini-Palazzi, G.; Di Cosimo, G.; Di Domenico, A.; Gauzzi, P.; Zanello, D.

    1991-01-01

    The scattering of thermal photons present in the vacuum pipe of LEP against the high energy positron beam has been detected. The spectrum of the back-scattered photons is presented for a positron beam energy of 46.1 GeV. Measurements have been performed in the interaction region 1 with the LEP-5 experiment calorimeter. (orig.)

  18. Bent crystal spectrometer for both frequency and wavenumber resolved x-ray scattering at a seeded free-electron laser.

    Science.gov (United States)

    Zastrau, Ulf; Fletcher, Luke B; Förster, Eckhart; Galtier, Eric Ch; Gamboa, Eliseo; Glenzer, Siegfried H; Heimann, Philipp; Marschner, Heike; Nagler, Bob; Schropp, Andreas; Wehrhan, Ortrud; Lee, Hae Ja

    2014-09-01

    We present a cylindrically curved GaAs x-ray spectrometer with energy resolution ΔE/E = 1.1 × 10(-4) and wave-number resolution of Δk/k = 3 × 10(-3), allowing plasmon scattering at the resolution limits of the Linac Coherent Light Source (LCLS) x-ray free-electron laser. It spans scattering wavenumbers of 3.6 to 5.2/Å in 100 separate bins, with only 0.34% wavenumber blurring. The dispersion of 0.418 eV/13.5 μm agrees with predictions within 1.3%. The reflection homogeneity over the entire wavenumber range was measured and used to normalize the amplitude of scattering spectra. The proposed spectrometer is superior to a mosaic highly annealed pyrolytic graphite spectrometer when the energy resolution needs to be comparable to the LCLS seeded bandwidth of 1 eV and a significant range of wavenumbers must be covered in one exposure.

  19. Simulation of effects of incident beam condition in p-p elastic scattering

    International Nuclear Information System (INIS)

    Yu Lei; Zhang Gaolong; Le Xiaoyun; Tanihata, I.

    2014-01-01

    The simulation is performed for the monitors of beam direction and beam position for p-p elastic scattering. We set several variables to simulate the monitors of incident beam condition changes: beam positions at the quadrupole magnet and target in beam line polarimeter (BLP2), distance between quadrupole magnet and target, size of plastic scintillators, distance between the target in BLP2 and the centers of plastic scintillators, and beam polarization. Through the rotation of the coordinate system, the distributions of scattered and recoiled protons in the laboratory system were obtained. By analyzing the count yields in plastic scintillators at different beam positions, we found that the beam incident angular change (0.35°) could be detected when the asymmetry of geometries of left and right scintillators in BLP2 was changed by 6%. Therefore, the scattering angle measured in the experiment can be tracked by these monitors. (authors)

  20. The SAGE spectrometer: A tool for combined in-beam γ-ray and conversion electron spectroscopy

    International Nuclear Information System (INIS)

    Papadakis, P; Herzberg, R-D; Pakarinen, J; Butler, P A; Cox, D; Cresswell, J R; Parr, E; Sampson, J; Greenlees, P T; Sorri, J; Hauschild, K; Jones, P; Julin, R; Peura, P; Rahkila, P; Sandzelius, M; Coleman-Smith, P J; Lazarus, I H; Letts, S C; Pucknell, V F E

    2011-01-01

    The SAGE spectrometer allows simultaneous in-beam γ-ray and internal conversion electron measurements, by combining a germanium detector array with a highly segmented silicon detector and an electron transport system. SAGE is coupled with the ritu gas-filled recoil separator and the great focal-plane spectrometer for recoil-decay tagging studies. Digital electronics are used both for the γ ray and the electron parts of the spectrometer. SAGE was commissioned in the Accelerator Laboratory of the University of Jyvaeskylae in the beginning of 2010.

  1. Active beam scattering apparatus and its application to JFT-2 tokamak

    International Nuclear Information System (INIS)

    Takeuchi, Hiroshi; Matsuda, Toshiaki; Nishitani, Takeo; Shiho, Makoto; Maeda, Hikosuke; Konagai, Chikara; Kimura, Hironobu.

    1983-09-01

    The capability to assess the ion temperatures using a neutral beam scattering system is investigated on the JFT-2 tokamak. The neutral beam scattering system consists of a 15 KeV neutral hydrogen atom beam and a momentum analyser with silicon surface barrier detectors. The energy analysis of scattered particles on the scattering angle of 4 0 gives the estimation of ion temperatures, which agree well with the one deduced from passive charge-exchange neutral measurements. The influence of impurity ions to the scattering spectrum is not observed and the results of gas scattering experiments suggests that this phenomenon occurs because of the ionization of neutral beam due to the collisions with impurity ions. (author)

  2. Probing the phase of the elastic pp scattering amplitude with vortex proton beams

    International Nuclear Information System (INIS)

    Ivanov, I. P.

    2013-01-01

    We show that colliding vortex proton beams instead of (approximate) plane waves can lead to a direct measurement of how the overall phase of the scattering amplitude changes with the scattering angle. In elastic pp scattering, this will open a novel way to measure the parameter ρ(t) and probe the real part of the Pomeron.

  3. Probing the phase of the elastic pp scattering amplitude with vortex proton beams

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, I. P. [IFPA, Universite de Liege, Allee du 6 Aout 17, batiment B5a, 4000 Liege, Belgium Sobolev Institute of Mathematics, Koptyug avenue 4, 630090, Novosibirsk (Russian Federation)

    2013-04-15

    We show that colliding vortex proton beams instead of (approximate) plane waves can lead to a direct measurement of how the overall phase of the scattering amplitude changes with the scattering angle. In elastic pp scattering, this will open a novel way to measure the parameter {rho}(t) and probe the real part of the Pomeron.

  4. The mass angular scattering power method for determining the kinetic energies of clinical electron beams

    International Nuclear Information System (INIS)

    Blais, N.; Podgorsak, E.B.

    1992-01-01

    A method for determining the kinetic energy of clinical electron beams is described, based on the measurement in air of the spatial spread of a pencil electron beam which is produced from the broad clinical electron beam. As predicted by the Fermi-Eyges theory, the dose distribution measured in air on a plane, perpendicular to the incident direction of the initial pencil electron beam, is Gaussian. The square of its spatial spread is related to the mass angular scattering power which in turn is related to the kinetic energy of the electron beam. The measured spatial spread may thus be used to determine the mass angular scattering power, which is then used to determine the kinetic energy of the electron beam from the known relationship between mass angular scattering power and kinetic energy. Energies obtained with the mass angular scattering power method agree with those obtained with the electron range method. (author)

  5. Scattering of aerosol particles by a Hermite-Gaussian beam in marine atmosphere.

    Science.gov (United States)

    Huang, Qingqing; Cheng, Mingjian; Guo, Lixin; Li, Jiangting; Yan, Xu; Liu, Songhua

    2017-07-01

    Based on the complex-source-point method and the generalized Lorenz-Mie theory, the scattering properties and polarization of aerosol particles by a Hermite-Gaussian (HG) beam in marine atmosphere is investigated. The influences of beam mode, beam width, and humidity on the scattered field are analyzed numerically. Results indicate that when the number of HG beam modes u (v) increase, the radar cross section of aerosol particles alternating appears at maximum and minimum values in the forward and backward scattering, respectively, because of the special petal-shaped distribution of the HG beam. The forward and backward scattering of aerosol particles decreases with the increase in beam waist. When beam waist is less than the radius of the aerosol particle, a minimum value is observed in the forward direction. The scattering properties of aerosol particles by the HG beam are more sensitive to the change in relative humidity compared with those by the plane wave and the Gaussian beam (GB). The HG beam shows superiority over the plane wave and the GB in detecting changes in the relative humidity of marine atmosphere aerosol. The effects of relative humidity on the polarization of the HG beam have been numerically analyzed in detail.

  6. Evaluation of a method for correction of scatter radiation in thorax cone beam CT

    International Nuclear Information System (INIS)

    Rinkel, J.; Dinten, J.M.; Esteve, F.

    2004-01-01

    Purpose: Cone beam CT (CBCT) enables three-dimensional imaging with isotropic resolution. X-ray scatter estimation is a big challenge for quantitative CBCT imaging of thorax: scatter level is significantly higher on cone beam systems compared to collimated fan beam systems. The effects of this scattered radiation are cupping artefacts, streaks, and quantification inaccuracies. The beam stops conventional scatter estimation approach can be used for CBCT but leads to a significant increase in terms of dose and acquisition time. At CEA-LETI has been developed an original scatter management process without supplementary acquisition. Methods and Materials: This Analytical Plus Indexing-based method (API) of scatter correction in CBCT is based on scatter calibration through offline acquisitions with beam stops on lucite plates, combined to an analytical transformation issued from physical equations. This approach has been applied with success in bone densitometry and mammography. To evaluate this method in CBCT, acquisitions from a thorax phantom with and without beam stops have been performed. To compare different scatter correction approaches, Feldkamp algorithm has been applied on rough data corrected from scatter by API and by beam stops approaches. Results: The API method provides results in good agreement with the beam stops array approach, suppressing cupping artefact. Otherwise influence of the scatter correction method on the noise in the reconstructed images has been evaluated. Conclusion: The results indicate that the API method is effective for quantitative CBCT imaging of thorax. Compared to a beam stops array method it needs a lower x-ray dose and shortens acquisition time. (authors)

  7. An in-beam Compton-suppressed Ge spectrometer for nondestructive neutron activation analysis

    International Nuclear Information System (INIS)

    Zaghloul, R.; Abd El-Haleam, A.; Mostafa, M.; Gantner, E.; Ache, H.J.

    1993-04-01

    A high-efficiency compton background suppressed gamma-ray spectrometer by anti-coincidence counting with a NaI(Tl)-shield around a central HPGe-detector for in-beam prompt gamma-ray neutron activation analysis (AC-PGNAA) using a Cf-252 neutron source has been designed and built to provide simultaneous anti-coincidence spectrometry of natural, industrial and environmental samples. The spectrometer consists of a high-purity germanium detector as the main detector and a large volume cylindrical NaI(Tl) detector as a guard detector. The assembly has the ability to measure instantaneously, simultaneously and nondestructively bulk samples up to about 50 cm 3 . Major constituent elements in several rocks and minerals such as H, B, N, Na, Mg, Al, Si, Cl, K, Ca, P, S, Ti, Fe, Sm, Nd, Mn and Gd can be determined, while oxygen cannot be measured due to its small capture cross section (0.27 mb). Several important minor and trace elements such as B, Cd and Hg beside the low residual activity, rare earths and short-lived isotopes could be detected. The sensitivity of the AC-PGNAA technique is limited by the available neutron flux at the target matrix and the neutron absorption cross section of the elements of interest. PGNAA has the advantage to estimate the constituent elements which are difficult to be measured through the delayed gamm-ray measurements such as B, Bi, C, H, P, Tl, Be, Cl and S in industrial and reference materials and those elements which are transformed into other stable isotopes when undergoing neutron capture. The design of the spectrometer assembly, its properties and performance are described

  8. Total cross section measurement of radioactive isotopes with a thin beam neutron spectrometer

    International Nuclear Information System (INIS)

    Razbudej, V.F.; Vertebnyj, V.P.; Padun, G.S.; Muravitskij, A.V.

    1975-01-01

    The method for measuring the neutron total cross sections of radioactive isotopes by a time-of-flight spectrometer with a narrow (0.17 mm in diameter) beam of thermal neutrons is described. The distinguishing feature of this method is the use of capillary samples with a small amount of substance (0.05-1.0 mg). The energy range is 0.01-0.3 eV. The total cross sections of irradiated samples of sub(153)Eu and sub(151)Eu are measured. From them are obtained the cross sections of sub(152)Eu (Tsub(1/2)=12.4 g) and of sub(154)E (Tsub(1/2)=8.6 yr); they equal 11400+-1400 and 1530+-190 barn at E=0.0253 eV. The cross section of the sub(152)Eu absorption for the thermal spectrum (T=333 K) is determined by the activation method; it is 8900+-1200 barn

  9. A new Thomson Spectrometer for high energy laser-driven beams diagnostic

    International Nuclear Information System (INIS)

    Cirrone, G A P; Tramontana, A; Candiano, G; Cavallaro, S; Cutroneo, M; Cuttone, G; Pisciotta, P; Romano, F; Schillaci, F; Scuderi, V; Torrisi, L; Carpinelli, M; Martinis, C De; Giove, D; Krása, J; Korn, G; Margarone, D; Prokůpek, J; Velyhan, A; Maggiore, M

    2014-01-01

    Thomson Spectrometers (TPs) are widely used for beam diagnostic as they provide simultaneous information on charge over mass ratio, energy and momentum of detected ions. A new TP design has been realized at INFN-LNS within the LILIA (Laser Induced Light Ion Acceleration) and ELIMED (MEDical application at ELI-Beamlines) projects. This paper reports on the construction details of the TP and on its experimental tests performed at PALS laboratory in Prague, with the ASTERIX IV laser system. Reported data are obtained with polyethylene and polyvinyl alcohol solid targets, they have been compared with data obtained from other detectors. Consistency among results confirms the correct functioning of the new TP. The main features, characterizing the design, are a wide acceptance of the deflection sector and a tunability of the, partially overlapping, magnetic and electric fields that allow to resolve ions with energy up to about 40 MeV for protons

  10. Studies on laser beam propagation and stimulated scattering in multiple beam experiments

    International Nuclear Information System (INIS)

    Labaune, C.; Lewis, K.; Bandulet, H.; Lewis, K.; Depierreux, S.; Huller, S.; Masson-Laborde, P.E.; Pesme, D.; Riazuelo, G.

    2006-01-01

    The propagation and stimulated scattering of intense laser beams interacting with underdense plasmas are two important issues for inertial confinement fusion (ICF). The purpose of this work was to perform experiments under well-controlled interaction conditions and confront them with numerical simulations to test the physics included in the codes. Experimental diagnostics include time and space resolved images of incident and SBS light and of SBS-ion acoustic activity. New numerical diagnostics, including similar constraints as the experimental ones and the treatment of the propagation of the light between the emitting area and the detectors, have been developed. Particular care was put to include realistic plasma density and velocity profiles, as well as laser pulse shape in the simulations. In the experiments presented in this paper, the interaction beam was used with a random phase plate (RPP) to produce a statistical distribution of speckles in the focal volume. Stimulated Brillouin Scattering (SBS) was described using a decomposition of the spatial scales which provides a predictive modeling of SBS in an expanding mm-scale plasma. Spatial and temporal behavior of the SBS-ion acoustic waves was found to be in good agreement with the experimental ones for two laser intensities. (authors)

  11. A high-efficiency spin-resolved photoemission spectrometer combining time-of-flight spectroscopy with exchange-scattering polarimetry

    Energy Technology Data Exchange (ETDEWEB)

    Jozwiak, Chris M.; Graff, Jeff; Lebedev, Gennadi; Andresen, Nord; Schmid, Andreas; Fedorov, Alexei; El Gabaly, Farid; Wan, Weishi; Lanzara, Alessandra; Hussain, Zahid

    2010-04-13

    We describe a spin-resolved electron spectrometer capable of uniquely efficient and high energy resolution measurements. Spin analysis is obtained through polarimetry based on low-energy exchange scattering from a ferromagnetic thin-film target. This approach can achieve a similar analyzing power (Sherman function) as state-of-the-art Mott scattering polarimeters, but with as much as 100 times improved efficiency due to increased reflectivity. Performance is further enhanced by integrating the polarimeter into a time-of-flight (TOF) based energy analysis scheme with a precise and flexible electrostatic lens system. The parallel acquisition of a range of electron kinetic energies afforded by the TOF approach results in an order of magnitude (or more) increase in efficiency compared to hemispherical analyzers. The lens system additionally features a 90 degrees bandpass filter, which by removing unwanted parts of the photoelectron distribution allows the TOF technique to be performed at low electron drift energy and high energy resolution within a wide range of experimental parameters. The spectrometer is ideally suited for high-resolution spin- and angle-resolved photoemission spectroscopy (spin-ARPES), and initial results are shown. The TOF approach makes the spectrometer especially ideal for time-resolved spin-ARPES experiments.

  12. Prior image constrained scatter correction in cone-beam computed tomography image-guided radiation therapy.

    Science.gov (United States)

    Brunner, Stephen; Nett, Brian E; Tolakanahalli, Ranjini; Chen, Guang-Hong

    2011-02-21

    X-ray scatter is a significant problem in cone-beam computed tomography when thicker objects and larger cone angles are used, as scattered radiation can lead to reduced contrast and CT number inaccuracy. Advances have been made in x-ray computed tomography (CT) by incorporating a high quality prior image into the image reconstruction process. In this paper, we extend this idea to correct scatter-induced shading artifacts in cone-beam CT image-guided radiation therapy. Specifically, this paper presents a new scatter correction algorithm which uses a prior image with low scatter artifacts to reduce shading artifacts in cone-beam CT images acquired under conditions of high scatter. The proposed correction algorithm begins with an empirical hypothesis that the target image can be written as a weighted summation of a series of basis images that are generated by raising the raw cone-beam projection data to different powers, and then, reconstructing using the standard filtered backprojection algorithm. The weight for each basis image is calculated by minimizing the difference between the target image and the prior image. The performance of the scatter correction algorithm is qualitatively and quantitatively evaluated through phantom studies using a Varian 2100 EX System with an on-board imager. Results show that the proposed scatter correction algorithm using a prior image with low scatter artifacts can substantially mitigate scatter-induced shading artifacts in both full-fan and half-fan modes.

  13. Transverse spin in the scattering of focused radially and azimuthally polarized vector beams

    Science.gov (United States)

    Singh, Ankit Kumar; Saha, Sudipta; Gupta, Subhasish Dutta; Ghosh, Nirmalya

    2018-04-01

    We study the effect of focusing of the radially and azimuthally polarized vector beams on the spin angular momentum (SAM) density and Poynting vector of scattered waves from a Mie particle. Remarkably, the study reveals that the SAM density of the scattered field is solely transverse in nature for radially and azimuthally polarized incident vector beams; however, the Poynting vector shows the usual longitudinal character. We also demonstrate that the transverse SAM density can further be tuned with wavelength and focusing of the incident beam by exploiting the interference of different scattering modes. These results may stimulate further experimental techniques to detect the transverse spin and Belinfante's spin-momentum densities.

  14. The optimisation of analyser geometry for a near back-scattering spectrometer. IRIS on the ISIS pulsed source

    International Nuclear Information System (INIS)

    Telling, M.T.F.; Campbell, S.I.

    1999-01-01

    This report describes the upgrade of the pyrolytic graphite (PG) analyser bank on the IRIS high-resolution inelastic spectrometer at ISIS from 1350 graphite pieces (6 rows by 225 columns) to 4212 crystal pieces (18 rows by 234 columns). The analyser array will achieve a three-fold increase in area and in addition the graphite crystals will be cooled close to liquid helium temperature to reduce thermal diffuse scattering, thereby further improving the sensitivity of the spectrometer. For an instrument such as IRIS, with its analyser out of exact back-scattering geometry, optical aberration and variation in the time-of-flight of the analysed neutrons is introduced as one moves out from the horizontal scattering plane. To minimise such effects, the profile of the analyser array has been redesigned. The concept behind the design of the new analyser bank and the factors that effect the overall resolution of the instrument are discussed. Results of Monte Carlo simulations of the expected resolution and intensity of the complete instrument are presented and compared to the current instrument performance. (author)

  15. Precision mechanical structure of an ultra-high-resolution spectrometer for inelastic X-ray scattering instrument

    Science.gov (United States)

    Shu, Deming; Shvydko, Yuri; Stoupin, Stanislav A.; Khachatryan, Ruben; Goetze, Kurt A.; Roberts, Timothy

    2015-04-14

    A method and an ultrahigh-resolution spectrometer including a precision mechanical structure for positioning inelastic X-ray scattering optics are provided. The spectrometer includes an X-ray monochromator and an X-ray analyzer, each including X-ray optics of a collimating (C) crystal, a pair of dispersing (D) element crystals, anomalous transmission filter (F) and a wavelength (W) selector crystal. A respective precision mechanical structure is provided with the X-ray monochromator and the X-ray analyzer. The precision mechanical structure includes a base plate, such as an aluminum base plate; positioning stages for D-crystal alignment; positioning stages with an incline sensor for C/F/W-crystal alignment, and the positioning stages including flexure-based high-stiffness structure.

  16. Detailed characterisation of the incident neutron beam on the TOSCA spectrometer

    Science.gov (United States)

    Pinna, Roberto S.; Rudić, Svemir; Capstick, Matthew J.; McPhail, David J.; Pooley, Daniel E.; Howells, Gareth D.; Gorini, Giuseppe; Fernandez-Alonso, Felix

    2017-10-01

    We report a detailed characterisation of the incident neutron beam on the TOSCA spectrometer. A bespoke time-of-flight neutron monitor has been designed, constructed and used to perform extensive spatially resolved measurements of the absolute neutron flux and its underlying time structure at the instrument sample position. The obtained data give a quantitative understanding of the current instrument beyond neutronic simulations and provide a baseline in order to assess the performance of the upgraded instrument. At an average proton current-on-target of 153 μA (ISIS Target Station 1; at the time of measurements) we have found that the wavelength-integrated neutron flux (from 0.28 Å to 4.65 Å) at the position of the TOSCA instrument sample (spatially averaged across the 3 × 3cm2 surface centred around (0,0) position) is approximately 1 . 2 × 106 neutrons cm-2s-1, while the whole beam has a homogeneous distribution across the 3 . 0 × 3 . 5cm2 sample surface. The spectra reproduced the well-known shape of the neutrons moderated by the room temperature water moderator and exhibit a neutron flux of 7 . 3 × 105 neutrons cm-2s-1Å-1 at 1 Å.

  17. Application of powder metallurgy beryllium in Beijing spectrometer III beam pipe

    International Nuclear Information System (INIS)

    Zheng Lifang; Li Xunfeng; Wang Li; Ji Quan; Liu Jianping

    2008-01-01

    According to the requirements of Beijing Spectrometer III (BESIII) beam pipe, the physical properties of several materials were compared and powder metallurgy beryllium was chosen as the material for the central pipe of the BES III beam pipe. Weight-loss method was used to study the corrosion of powder metallurgy beryllium in No. 1 oil for electron discharge machining (EDM-1). The result shows that the anticorrosive property of powder metallurgy beryllium in EDM-1 is high. The corrosion rate, 4.18 x 10 -7 kg· m -2 ·h -1 in initial stage, becomes small with the lapse of the time and stabilizes at 1.54 x 10 -7 kg·m -2 ·h -1 at last. It can be estimated that the powder metallurgy beryllium will be corroded 19.9 μm in the depth in 10 years and it accounts for 3.32% of the smallest thickness of the central pipe, which satisfies the requirements of the BESIII. (authors)

  18. Investigation of the ion beam of the Titan source by the time-of-flight mass spectrometer

    International Nuclear Information System (INIS)

    Bugaev, A.S.; Gushenets, V.V.; Nikolaev, A.G.; Yushkov, G.Yu.

    2000-01-01

    The Titan ion source generates wide-aperture beams of both gaseous and metal ions of various materials. The above possibility is realized on the account of combining two types of arc discharge with cold cathodes in the source discharge system. The vacuum arc, initiated between the cathode accomplished from the ion forming material, and hollow anode, is used for obtaining the metal ions. The pinch-effect low pressure arc discharge, ignited on the same hollow anode, is used for obtaining gaseous ions. The composition of ion beams, generated by the Titan source through the specially designed time-of-flight spectrometer, is studied. The spectrometer design and principle pf operation are presented. The physical peculiarities of the source functioning, influencing the ion beam composition, are discussed [ru

  19. A general framework and review of scatter correction methods in cone beam CT. Part 2: Scatter estimation approaches

    International Nuclear Information System (INIS)

    Ruehrnschopf and, Ernst-Peter; Klingenbeck, Klaus

    2011-01-01

    The main components of scatter correction procedures are scatter estimation and a scatter compensation algorithm. This paper completes a previous paper where a general framework for scatter compensation was presented under the prerequisite that a scatter estimation method is already available. In the current paper, the authors give a systematic review of the variety of scatter estimation approaches. Scatter estimation methods are based on measurements, mathematical-physical models, or combinations of both. For completeness they present an overview of measurement-based methods, but the main topic is the theoretically more demanding models, as analytical, Monte-Carlo, and hybrid models. Further classifications are 3D image-based and 2D projection-based approaches. The authors present a system-theoretic framework, which allows to proceed top-down from a general 3D formulation, by successive approximations, to efficient 2D approaches. A widely useful method is the beam-scatter-kernel superposition approach. Together with the review of standard methods, the authors discuss their limitations and how to take into account the issues of object dependency, spatial variance, deformation of scatter kernels, external and internal absorbers. Open questions for further investigations are indicated. Finally, the authors refer on some special issues and applications, such as bow-tie filter, offset detector, truncated data, and dual-source CT.

  20. Self-scattering cross-section of molecules in a beam

    International Nuclear Information System (INIS)

    Lou, Y.S.

    1974-01-01

    Molecular collision cross-section has always been measured by the beam scattering method, or by the measurements of thermal conductivity and/or viscosity coefficient, etc. The cross-section thus obtained has been found to be different, qualitatively, from that of the self-scattering of the molecules moving within a molecular beam. By perturbing the zeroth order solution of the Boltzmann equation with a B-G-K kinetic model for the gas upstream to the orifice, and performing particle scattering calculation for molecules within the beam downstream to the orifice, such self-scattering collision cross-section can be determined from the experimental data of velocity distribution functions of molecules in the beam

  1. Choice of theoretical model for beam scattering at accelerator output foil for particle energy determination

    International Nuclear Information System (INIS)

    Balagyra, V.S.; Ryabka, P.M.

    1999-01-01

    For measuring the charged particle energy calculations of mean square angles of electron beam multiple Coulomb scattering at output combined accelerator target were undertaken according to seven theoretical models. Mollier method showed the best agreement with experiments

  2. Simulating the influence of scatter and beam hardening in dimensional computed tomography

    Science.gov (United States)

    Lifton, J. J.; Carmignato, S.

    2017-10-01

    Cone-beam x-ray computed tomography (XCT) is a radiographic scanning technique that allows the non-destructive dimensional measurement of an object’s internal and external features. XCT measurements are influenced by a number of different factors that are poorly understood. This work investigates how non-linear x-ray attenuation caused by beam hardening and scatter influences XCT-based dimensional measurements through the use of simulated data. For the measurement task considered, both scatter and beam hardening are found to influence dimensional measurements when evaluated using the ISO50 surface determination method. On the other hand, only beam hardening is found to influence dimensional measurements when evaluated using an advanced surface determination method. Based on the results presented, recommendations on the use of beam hardening and scatter correction for dimensional XCT are given.

  3. Beam-guiding system for Rutherford-scattering diagnostic at TEXTOR

    International Nuclear Information System (INIS)

    Cosler, A; Bertschinger, G.; Kemmereit, E.; Ven, H.W. van der; Barbian, E.P.; Blokland, A.A.E. van

    1988-01-01

    A beam-guiding system for a neutral beam probe diagnostic has been developed for implementation at TEXTOR. Energetic helium atoms scattered on the plasma ions provide information about the local ion temperature. Time resolution is attained by sampling scattered particles measured individually by a time-of-flight analyser. The mechanical supports have been designed for lateral and angular movement of the beam-guiding system to be used for radial scanning of the torus and for optimization of the scattering angle. The parameters of the probing beam itself can be controlled jby a small beam profile diagnsotic. Provisions are made to observe separately the radial or axial component of the ion velocity distribution. (author). 10 refs.; 7 figs

  4. Performance of the Recoil Mass Spectrometer and its detector systems at the Holifield Radioactive Ion Beam Facility

    International Nuclear Information System (INIS)

    Gross, C.J.; Ginter, T.N.; Shapira, D.; Milner, W.T.; McConnell, J.W.; James, A.N.; Johnson, J.W.; Mas, J.; Mantica, P.F.; Auble, R.L.; Das, J.J.; Blankenship, J.L.; Hamilton, J.H.; Robinson, R.L.; Akovali, Y.A.; Baktash, C.; Batchelder, J.C.; Bingham, C.R.; Brinkman, M.J.; Carter, H.K.; Cunningham, R.A.; Davinson, T.; Fox, J.D.; Galindo-Uribarri, A.; Grzywacz, R.; Liang, J.F.; MacDonald, B.D.; MacKenzie, J.; Paul, S.D.; Piechaczek, A.; Radford, D.C.; Ramayya, A.V.; Reviol, W.; Rudolph, D.; Rykaczewski, K.; Toth, K.S.; Weintraub, W.; Williams, C.; Woods, P.J.; Yu, C.-H.; Zganjar, E.F.

    2000-01-01

    The recently commissioned Recoil Mass Spectrometer (RMS) at the Holifield Radioactive Ion Beam Facility (HRIBF) is described. Consisting of a momentum separator followed by an E-D-E Rochester-type mass spectrometer, the RMS is the centerpiece of the nuclear structure endstation at the HRIBF. Designed to transport ions with rigidities near K=100, the RMS has acceptances of ±10% in energy and ±4.9% in mass-to-charge ratio. Recent experimental results are used to illustrate the detection capabilities of the RMS, which is compatible with many detectors and devices

  5. Dosimetry and microdosimetry using LET spectrometer based on the track-etch detector: radiotherapy Bremsstrahlung beam, onboard aircraft radiation field

    International Nuclear Information System (INIS)

    Jadrnickova, I.; Spurny, F.

    2006-01-01

    The spectrometer of linear energy transfer (Let) based on the chemically etched poly-allyl-diglycol-carbonate (P.A.D.C.) track-etch detector was developed several years ago in our institute. This Let spectrometer enables determining Let of particles approximately from 10 to 700 keV/μm. From the Let spectra, dose characteristics can be calculated. The contribution presents the Let spectra and other dosimetric characteristics obtained onboard a commercial aircraft during more than 6 months long exposure and in the 18 MV radiotherapy Bremsstrahlung beam. (authors)

  6. Scattering of Gaussian beam by a spherical particle with a spheroidal inclusion

    International Nuclear Information System (INIS)

    Zhang Huayong; Liao Tongqing

    2011-01-01

    A generalized Lorenz-Mie theory framework (GLMT) is applied to the study of Gaussian beam scattering by a spherical particle with an embedded spheroid at the center. By virtue of a transformation between the spherical and spheroidal vector wave functions, a theoretical procedure is developed to deal with the boundary conditions. Numerical results of the normalized differential scattering cross section are presented.

  7. Computational method for an axisymmetric laser beam scattered by a body of revolution

    International Nuclear Information System (INIS)

    Combis, P.; Robiche, J.

    2005-01-01

    An original hybrid computational method to solve the 2-D problem of the scattering of an axisymmetric laser beam by an arbitrary-shaped inhomogeneous body of revolution is presented. This method relies on a domain decomposition of the scattering zone into concentric spherical radially homogeneous sub-domains and on an expansion of the angular dependence of the fields on the Legendre polynomials. Numerical results for the fields obtained for various scatterers geometries are presented and analyzed. (authors)

  8. Inelastic neutron scattering experiments with the monochromatic imaging mode of the RITA-II spectrometer

    DEFF Research Database (Denmark)

    Bahl, Christian Robert Haffenden; Lefmann, Kim; Abrahamsen, Asger Bech

    2006-01-01

    Recently a monochromatic multiple data taking mode has been demonstrated for diffraction experiments using a RITA type cold neutron spectrometer with a multi-bladed analyser and a position-sensitive detector. Here, we show how this mode can be used in combination with a flexible radial collimator...

  9. Collective Thomson scattering of a high power electron cyclotron resonance heating beam in LHD

    DEFF Research Database (Denmark)

    Kubo, S.; Nishiura, M.; Tanaka, K.

    2010-01-01

    Collective Thomson scattering (CTS) system has been constructed at LHD making use of the high power ECRH system in LHD. The necessary features for CTS, high power probing beams and receiving beams, both with well defined Gaussian profile and with the fine controllability, are endowed in the ECRH ...

  10. Thomson scattering of polarized photons in an intense laser beam

    Energy Technology Data Exchange (ETDEWEB)

    Byung Yunn

    2006-02-21

    We present a theoretical analysis of the Thomson scattering of linearly and circularly polarized photons from a pulsed laser by electrons. The analytical expression for the photon distribution functions presented in this paper should be useful to designers of Thomson scattering experiments.

  11. Neutron scattering studies of the dynamics of biopolymer-water systems using pulsed-source spectrometers

    Energy Technology Data Exchange (ETDEWEB)

    Middendorf, H.D. [Univ. of Oxford (United Kingdom); Miller, A. [Stirling Univ., Stirling (United Kingdom)

    1994-12-31

    Energy-resolving neutron scattering techniques provide spatiotemporal data suitable for testing and refining analytical models or computer simulations of a variety of dynamical processes in biomolecular systems. This paper reviews experimental work on hydrated biopolymers at ISIS, the UK Pulsed Neutron Facility. Following an outline of basic concepts and a summary of the new instrumental capabilities, the progress made is illustrated by results from recent experiments in two areas: quasi- elastic scattering from highly hydrated polysaccharide gels (agarose and hyaluronate), and inelastic scattering from vibrational modes of slightly hydrated collagen fibers.

  12. Neutron scattering studies of the dynamics of biopolymer-water systems using pulsed-source spectrometers

    International Nuclear Information System (INIS)

    Middendorf, H.D.; Miller, A.

    1994-01-01

    Energy-resolving neutron scattering techniques provide spatiotemporal data suitable for testing and refining analytical models or computer simulations of a variety of dynamical processes in biomolecular systems. This paper reviews experimental work on hydrated biopolymers at ISIS, the UK Pulsed Neutron Facility. Following an outline of basic concepts and a summary of the new instrumental capabilities, the progress made is illustrated by results from recent experiments in two areas: quasi- elastic scattering from highly hydrated polysaccharide gels (agarose and hyaluronate), and inelastic scattering from vibrational modes of slightly hydrated collagen fibers

  13. Angular scattering in electron capture and loss D- beam formation processes

    International Nuclear Information System (INIS)

    Coggiola, M.J.; Hodges, R.V.; Huestis, D.L.; Peterson, J.R.

    1980-01-01

    The development of high energy (> 150 keV) neutral beams for heating and fueling magnetic fusion devices depends on the ability to produce well-collimated negative ion beams. The double capture charge-exchange technique is a known, scalable method. In order to maximize the overall efficiency of the process and to achieve the desired beam characteristics, it is necessary to examine the optical qualities of the beams as well as the total efficiency of beam production. A combined modeling and experimental study of the angular scattering effects in negative ion formation and loss processes has therefore been undertaken

  14. Atomic scattering from an adsorbed monolayer solid with a helium beam that penetrates to the substrate

    DEFF Research Database (Denmark)

    Hansen, Flemming Yssing; Bruch, L.W.; Dammann, Bernd

    2013-01-01

    Diffraction and one-phonon inelastic scattering of a thermal energy helium atomic beam are evaluated in the situation that the target monolayer lattice is so dilated that the atomic beam penetrates to the interlayer region between the monolayer and the substrate. The scattering is simulated......(1 × 1) commensurate monolayer solid of H2/KCl(001). For the latter, there are cases where part of the incident beam is trapped in the interlayer region for times exceeding 50 ps, depending on the spacing between the monolayer and the substrate and on the angle of incidence. The feedback effect...

  15. Arbitrary scattering of an acoustical Bessel beam by a rigid spheroid with large aspect-ratio

    Science.gov (United States)

    Gong, Zhixiong; Li, Wei; Mitri, Farid G.; Chai, Yingbin; Zhao, Yao

    2016-11-01

    In this paper, the T-matrix (null-field) method is applied to investigate the acoustic scattering by a large-aspect-ratio rigid spheroid immersed in a non-viscous fluid under the illumination of an unbounded zeroth-order Bessel beam with arbitrary orientation. Based on the proposed method, a MATLAB software package is constructed accordingly, and then verified and validated to compute the acoustic scattering by a rigid oblate or prolate spheroid in the Bessel beam. Several numerical examples are carried out to investigate the novel phenomenon of acoustic scattering by spheroids in Bessel beams with arbitrary incidence, with particular emphasis on the aspect ratio (i.e. the ratio of the polar radius over the equatorial radius of the spheroid), the half-cone angle of Bessel beam, the dimensionless frequency, as well as the angle of incidence. The quasi-periodic oscillations are observed in the plots of the far-field backscattering form function modulus versus the dimensionless frequency, owing to the interference between the specular reflection and the Franz wave circumnavigating the spheroid in the surrounding fluid. Furthermore, the 3D far-field scattering directivity patterns at end-on incidence and 2D polar plots at arbitrary angles of incidence are exhibited, which could provide new insights into the physical mechanisms of Bessel beam scattering by flat or elongated spheroid. This research work may provide an impetus for the application of acoustic Bessel beam in engineering practices.

  16. SU-F-T-137: Out-Of-Beam Dose for a Compact Double-Scattering Proton Beam Therapy System

    Energy Technology Data Exchange (ETDEWEB)

    Islam, M; Ahmad, S; Jin, H [University of Oklahoma Health Sciences Center, Oklahoma City, OK (United States)

    2016-06-15

    Purpose: The out-of-beam dose is important for understanding the peripheral dose in radiation therapy. In proton radiotherapy, the study of out-of-beam dose is scarce and the treatment planning system (TPS) based on pencil beam algorithm cannot accurately predict the out-of-beam dose. This study investigates the out-of-beam dose for the single-room Mevion S250 double scattering proton therapy system using experimentally measured and treatment planning software generated data. The results are compared with those reported for conventional photon beam therapy. However, this study does not incorporate the neutron contribution in the scattered dose. Methods: A total of seven proton treatment plans were generated using Varian Eclipse TPS for three different sites (brain, lung, and pelvis) in an anthropomorphic phantom. Three field sizes of 5×5, 10×10, and 20×20 cm{sup 2} (lung only) with typical clinical range (13.3–22.8 g/cm{sup 2}) and modulation widths (5.3–14.0 g/cm{sup 2}) were used. A single beam was employed in each treatment plan to deliver a dose of 181.8 cGy (200.0 cGy (RBE)) to the selected target. The out-of-beam dose was measured at 2.0, 5.0, 10.0, and 15.0 cm from the beam edge in the phantom using a thimble chamber (PTW TN31010). Results: The out-of-beam dose generally increased with field size, range, and volume irradiated. For all the plans, the scattered dose sharply fell off with distance. At 2.0 cm, the out-of-beam dose ranged from 0.35% to 2.16% of the delivered dose; however, the dose was clinically negligible (<0.3%) at a distance of 5.0 cm and greater. In photon therapy, the slightly greater out-of-beam dose was reported (TG36; 4%, 2%, and 1% for 2.0, 5.0, and 10.0 cm, respectively, using 6 MV beam). Conclusion: The measured out-of-beam dose in proton therapy excluding neutron contribution was observed higher than the TPS calculated dose and comparable to that of photon beam therapy.

  17. A molecular beam machine for the measurement of the scattering of polar diatomic molecules

    International Nuclear Information System (INIS)

    Everdij, J.J.

    1976-01-01

    This thesis describes an experimental method to determine the long range, angular dependent part of the intermolecular potential between a polar diatomic molecule and a spherical symmetric partner. The method contains the study of the scattering behaviour of the molecules in a crossed beam experiment. The primary beam consisting of polar diatomic molecules at thermal velocities (approximately 0.1 eV), is selected in a specified rotational state by means of an electrostatic, inhomogeneous field before the scattering center, where it crosses the (supersonic) secondary beam under an angle of 90 0 . By means of a second state selector, followed by a velocity selector and a particle detector, the consequences are studied of the scattering process on the primary beam, i.e. the behaviour of the total and differential elastic cross sections plus the transition probability of a collision induced transition to another rotational state. (Auth.)

  18. Experimental study of pion-nucleus elastic scattering above the Δ-resonance with the SKS spectrometer

    International Nuclear Information System (INIS)

    Takahashi, Toshiyuki

    1995-11-01

    Differential cross sections of the pion elastic scattering in the GeV/c region were systematically measured by using a newly constructed superconducting kaon spectrometer at KEK. The pion incident momenta were 610, 710, 790, and 895 MeV/c for 12 C(π - , π - ) 12 C and 790 MeV/c for 208 Pb(π ± , π ± ) 208 Pb. We have obtained the cross sections with absolute normalization uncertainty of about 10%. The π - -p scattering data measured with a CH target agree well with the phase-shift calculations, which confirms the accuracy of the absolute values of the cross sections. The angular distributions of the differential cross sections for 12 C were compared with calculations by a first-order optical potential model. The calculation reproduces the data at forward scattering-angle regions except at 610 MeV/c, although it underestimates at large-angle region. The present data at 790 MeV/c are in between the BNL data at 800 MeV/c and the calculation, although our data are consistent with the BNL data within their systematic errors. The incident momentum dependence of σ total , σ R , and σ elastic , which were extracted by fitting the angular distributions, is different from that of the calculation with free π-N elementary amplitudes. It is well explained by taking account of Fermi motion. The 208 Pb data are well reproduced by the optical potential model. The root mean square radius of the neutron distribution has been deduced from π + and π - elastic scattering for the first time. Although the result has a model ambiguity, it agrees with that deduced from the proton elastic scattering. It is, however, smaller than the prediction of the relativistic Hartree calculation. (author). 55 refs

  19. Direct coupling of a dense (supercritical) gas chromatograph to a mass spectrometer using a supersonic molecular beam interface

    International Nuclear Information System (INIS)

    Randall, L.G.; Wahrhaftig, A.L.

    1981-01-01

    A detecting mass spectrometer has been successfully coupled to a dense gas (supercritical fluid) chromatograph to produce an instrument (DGC/MS) that may be an alternative to high performance liquid chromatograph/mass spectrometer instruments (HPLC/MS) and gas chromatograph/mass spectrometer instruments (GC/MS) for analysis of involatile and/or thermally labile compounds. The mobile phase in DGC is a gas held at temperatures above the critical temperature and at pressures sufficient to obtain nearly liquid-like densities. DGC combines advantages of GC and HPLC: rapid separations, moderate operating temperatures, and analysis of involatile compounds. An advantage unique to DGC is the solvent power dependence upon pressure. While several groups have studied DGC, its development has been limited by the lack of a sensitive and selective detector. Hence, work has been directed towards the design and construction of a DGC/MS resulting in a trial instrument capable of chromatographic pressures of at least 300 atm and temperatures from 10 0 to 60 0 C. The DGC/MS coupling has been accomplished by the use of a supersonic molecular beam interface. This application of molecular beam formation appears to be unique in its requirements of a large pressure ratio (approx.10 8 ), low flow rates, and low final pressures. The authors outline characteristics of supersonic jets and molecular beams pertinent to the design of such an instrument. The interface which uses pumping speeds of 2400 and 1200 l/s in the beam forming chambers is described in detail, while the other components: the detecting mass spectrometer, the dense gas supply, and the DGC: are briefly described. Preliminary work with this instrument has established the feasibility of DGC/MS as an analytical technique and further development is recommended

  20. Nuclear-mass dependence of azimuthal beam-helicity and beam-charge asymmetries in deeply virtual Compton scattering

    International Nuclear Information System (INIS)

    Airapetian, A.; Akopov, Z.

    2009-11-01

    The nuclear-mass dependence of azimuthal cross section asymmetries with respect to charge and longitudinal polarization of the lepton beam is studied for hard exclusive electroproduction of real photons. The observed beam-charge and beam-helicity asymmetries are attributed to the interference between the Bethe-Heitler and deeply virtual Compton scattering processes. For various nuclei, the asymmetries are extracted for both coherent and incoherent-enriched regions, which involve different (combinations of) generalized parton distributions. For both regions, the asymmetries are compared to those for a free proton, and no nuclear-mass dependence is found. (orig.)

  1. Light scattering of a Bessel beam by a nucleated biological cell: An eccentric sphere model

    Science.gov (United States)

    Wang, Jia Jie; Han, Yi Ping; Chang, Jiao Yong; Chen, Zhu Yang

    2018-02-01

    Within the framework of generalized Lorenz-Mie theory (GLMT), an eccentrically stratified dielectric sphere model illuminated by an arbitrarily incident Bessel beam is applied to investigate the scattering characteristics of a single nucleated biological cell. The Bessel beam propagating in an arbitrary direction is expanded in terms of vector spherical wave functions (VSWFs), where the beam shape coefficients (BSCs) are calculated rigorously in a closed analytical form. The effects of the half-cone angle of Bessel beam, the location of the particle in the beam, the size ratio of nucleus to cell, and the location of the nucleus inside the cell on the scattering properties of a nucleated cell are analyzed. The results provide useful references for optical diagnostic and imaging of particle having nucleated structure.

  2. The electron beam dynamics simulation in the laser-electron storage ring involving compton and intrabeam scattering

    International Nuclear Information System (INIS)

    Gladkikh, P.I.; Telegin, Yu.N.; Karnaukhov, I.M.

    2002-01-01

    The feasibility of the development of intense X-ray sources based on Compton scattering in laser-electron storage rings is discussed. The results of the electron beam dynamics simulation involving Compton and intrabeam scattering are presented

  3. The electron beam dynamics simulation in the laser-electron storage ring involving compton and intrabeam scattering

    CERN Document Server

    Gladkikh, P I; Karnaukhov, I M

    2002-01-01

    The feasibility of the development of intense X-ray sources based on Compton scattering in laser-electron storage rings is discussed. The results of the electron beam dynamics simulation involving Compton and intrabeam scattering are presented.

  4. Enhancing the performances of a resonance detector spectrometer for deep inelastic neutron scattering measurements

    International Nuclear Information System (INIS)

    Filabozzi, A.; Pace, E.; Pietropaolo, A.

    2012-01-01

    The possibility is explored to sum up neutron Compton profiles at different scattering angles in deep inelastic neutron scattering measurements within the Resonance Detector (RD) configuration to enhance the statistics for a more reliable extraction of the momentum distribution of the constituents in the target. The RD configuration allows to select the energy of the scattered neutrons up to several tens of electron Volt, thus accessing energy and wave vector transfers well above 1 eV and 30 Å −1 , respectively. In the high-q/ω regime, the final state effects could be considered as negligible, as shown in a series of simulations using a Monte Carlo method with different inverse geometry instrument setups. The simulations show that it could be possible to conceive an instrument set up where the RD configuration allows the proper summation of several spectra at different scattering angles, providing a good separation of the proton recoil signal from that of the heavier atoms, thus avoiding the cell subtraction by fitting procedure.

  5. Combined inclusive diffractive cross sections measured with forward proton spectrometers in deep inelastic ep scattering at HERA

    CERN Document Server

    Aaron, F.D.; Abt, I.; Adamczyk, L.; Adamus, M.; Aggarwal, R.; Alexa, C.; Andreev, V.; Antonelli, S.; Antonioli, P.; Antonov, A.; Arneodo, M.; Arslan, O.; Aushev, V.; Aushev, Y.; Bachynska, O.; Backovic, S.; Baghdasaryan, A.; Baghdasaryan, S.; Bamberger, A.; Barakbaev, A.N.; Barbagli, G.; Bari, G.; Barreiro, F.; Barrelet, E.; Bartel, W.; Bartosik, N.; Bartsch, D.; Basile, M.; Begzsuren, K.; Behnke, O.; Behr, J.; Behrens, U.; Bellagamba, L.; Belousov, A.; Belov, P.; Bertolin, A.; Bhadra, S.; Bindi, M.; Bizot, J.C.; Blohm, C.; Bokhonov, V.; Bondarenko, K.; Boos, E.G.; Borras, K.; Boscherini, D.; Bot, D.; Boudry, V.; Bozovic-Jelisavcic, I.; Bold, T.; Brummer, N.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Britzger, D.; Brock, I.; Brownson, E.; Brugnera, R.; Bruncko, D.; Bruni, A.; Bruni, G.; Brzozowska, B.; Bunyatyan, A.; Bussey, P.J.; Bylinkin, A.; Bylsma, B.; Bystritskaya, L.; Caldwell, A.; Campbell, A.J.; Cantun Avila, K.B.; Capua, M.; Carlin, R.; Catterall, C.D.; Ceccopieri, F.; Cerny, K.; Cerny, V.; Chekanov, S.; Chekelian, V.; Chwastowski, J.; Ciborowski, J.; Ciesielski, R.; Cifarelli, L.; Cindolo, F.; Contin, A.; Contreras, J.G.; Cooper-Sarkar, A.M.; Coppola, N.; Corradi, M.; Corriveau, F.; Costa, M.; Coughlan, J.A.; Cvach, J.; D'Agostini, G.; Dainton, J.B.; Dal Corso, F.; Daum, K.; Delcourt, B.; Delvax, J.; Dementiev, R.K.; Derrick, M.; Devenish, R.C.E.; De Pasquale, S.; De Wolf, E.A.; del Peso, J.; Diaconu, C.; Dobre, M.; Dobur, D.; Dodonov, V.; Dolgoshein, B.A.; Dolinska, G.; Dossanov, A.; Doyle, A.T.; Drugakov, V.; Dubak, A.; Durkin, L.S.; Dusini, S.; Eckerlin, G.; Egli, S.; Eisenberg, Y.; Eliseev, A.; Elsen, E.; Ermolov, P.F.; Eskreys, A.; Fang, S.; Favart, L.; Fazio, S.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Ferrando, J.; Ferrero, M.I.; Figiel, J.; Fischer, D.J.; Fleischer, M.; Fomenko, A.; Forrest, M.; Foster, B.; Gabathuler, E.; Gach, G.; Galas, A.; Gallo, E.; Garfagnini, A.; Gayler, J.; Geiser, A.; Ghazaryan, S.; Gialas, I.; Gizhko, A.; Gladilin, L.K.; Gladkov, D.; Glasman, C.; Glazov, A.; Goerlich, L.; Gogitidze, N.; Gogota, O.; Golubkov, Yu.A.; Gottlicher, P.; Gouzevitch, M.; Grab, C.; Grabowska-Bold, I.; Grebenyuk, A.; Grebenyuk, J.; Greenshaw, T.; Gregor, I.; Grigorescu, G.; Grindhammer, G.; Grzelak, G.; Gueta, O.; Guzik, M.; Gwenlan, C.; Huttmann, A.; Haas, T.; Habib, S.; Haidt, D.; Hain, W.; Hamatsu, R.; Hart, J.C.; Hartmann, H.; Hartner, G.; Henderson, R.C.W.; Hennekemper, E.; Henschel, H.; Herbst, M.; Herrera, G.; Hildebrandt, M.; Hilger, E.; Hiller, K.H.; Hladky, J.; Hochman, D.; Hoffmann, D.; Hori, R.; Horisberger, R.; Hreus, T.; Huber, F.; Ibrahim, Z.A.; Iga, Y.; Ingbir, R.; Ishitsuka, M.; Jacquet, M.; Jakob, H.P.; Janssen, X.; Januschek, F.; Jones, T.W.; Jonsson, L.; Jungst, M.; Jung, H.; Kadenko, I.; Kahle, B.; Kananov, S.; Kanno, T.; Kapichine, M.; Karshon, U.; Karstens, F.; Katkov, I.I.; Kaur, P.; Kaur, M.; Kenyon, I.R.; Keramidas, A.; Khein, L.A.; Kiesling, C.; Kim, J.Y.; Kisielewska, D.; Kitamura, S.; Klanner, R.; Klein, M.; Klein, U.; Kleinwort, C.; Koffeman, E.; Kogler, R.; Kondrashova, N.; Kononenko, O.; Kooijman, P.; Korol, Ie.; Korzhavina, I.A.; Kostka, P.; Kotanski, A.; Kotz, U.; Kowalski, H.; Kramer, M.; Kretzschmar, J.; Kruger, K.; Kuprash, O.; Kuze, M.; Landon, M.P.J.; Lange, W.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Lee, A.; Lendermann, V.; Levchenko, B.B.; Levonian, S.; Levy, A.; Libov, V.; Limentani, S.; Ling, T.Y.; Lipka, K.; Lisovyi, M.; List, B.; List, J.; Lobodzinska, E.; Lobodzinski, B.; Lohmann, W.; Lohr, B.; Lohrmann, E.; Long, K.R.; Longhin, A.; Lontkovskyi, D.; Lopez-Fernandez, R.; Lubimov, V.; Lukina, O.Yu.; Maeda, J.; Magill, S.; Makarenko, I.; Malinovski, E.; Malka, J.; Mankel, R.; Margotti, A.; Marini, G.; Martin, J.F.; Martyn, H.U.; Mastroberardino, A.; Mattingly, M.C.K.; Maxfield, S.J.; Mehta, A.; Melzer-Pellmann, I.A.; Mergelmeyer, S.; Meyer, A.B.; Meyer, H.; Meyer, J.; Miglioranzi, S.; Mikocki, S.; Milcewicz-Mika, I.; Idris, F.Mohamad; Monaco, V.; Montanari, A.; Moreau, F.; Morozov, A.; Morris, J.V.; Morris, J.D.; Mujkic, K.; Muller, K.; Musgrave, B.; Nagano, K.; Namsoo, T.; Nania, R.; Naumann, Th.; Newman, P.R.; Niebuhr, C.; Nigro, A.; Nikitin, D.; Ning, Y.; Nobe, T.; Notz, D.; Nowak, G.; Nowak, K.; Nowak, R.J.; Nuncio-Quiroz, A.E.; Oh, B.Y.; Okazaki, N.; Olkiewicz, K.; Olsson, J.E.; Onishchuk, Yu.; Ozerov, D.; Pahl, P.; Palichik, V.; Pandurovic, M.; Papageorgiu, K.; Parenti, A.; Pascaud, C.; Patel, G.D.; Paul, E.; Pawlak, J.M.; Pawlik, B.; Pelfer, P.G.; Pellegrino, A.; Perez, E.; Perlanski, W.; Perrey, H.; Petrukhin, A.; Picuric, I.; Piotrzkowski, K.; Pirumov, H.; Pitzl, D.; Placakyte, R.; Plucinski, P.; Pokorny, B.; Pokrovskiy, N.S.; Polifka, R.; Polini, A.; Povh, B.; Proskuryakov, A.S.; Przybycien, M.; Radescu, V.; Raicevic, N.; Raval, A.; Ravdandorj, T.; Reeder, D.D.; Reimer, P.; Reisert, B.; Ren, Z.; Repond, J.; Ri, Y.D.; Rizvi, E.; Robertson, A.; Robmann, P.; Roloff, P.; Roosen, R.; Rostovtsev, A.; Rotaru, M.; Rubinsky, I.; Ruiz Tabasco, J.E.; Rusakov, S.; Ruspa, M.; Sacchi, R.; Salek, D.; Samson, U.; Sankey, D.P.C.; Sartorelli, G.; Sauter, M.; Sauvan, E.; Savin, A.A.; Saxon, D.H.; Schioppa, M.; Schlenstedt, S.; Schleper, P.; Schmidke, W.B.; Schmitt, S.; Schneekloth, U.; Schoeffel, L.; Schonberg, V.; Schoning, A.; Schorner-Sadenius, T.; Schultz-Coulon, H.C.; Schwartz, J.; Sciulli, F.; Sefkow, F.; Shcheglova, L.M.; Shehzadi, R.; Shimizu, S.; Shtarkov, L.N.; Shushkevich, S.; Singh, I.; Skillicorn, I.O.; Slominski, W.; Sloan, T.; Smith, W.H.; Sola, V.; Solano, A.; Soloviev, Y.; Son, D.; Sopicki, P.; Sosnovtsev, V.; South, D.; Spaskov, V.; Specka, A.; Spiridonov, A.; Stadie, H.; Stanco, L.; Staykova, Z.; Steder, M.; Stefaniuk, N.; Stella, B.; Stern, A.; Stewart, T.P.; Stifutkin, A.; Stoicea, G.; Stopa, P.; Straumann, U.; Suchkov, S.; Susinno, G.; Suszycki, L.; Sykora, T.; Sztuk-Dambietz, J.; Szuba, J.; Szuba, D.; Tapper, A.D.; Tassi, E.; Terron, J.; Theedt, T.; Thompson, P.D.; Tiecke, H.; Tokushuku, K.; Tomaszewska, J.; Tran, T.H.; Traynor, D.; Truol, P.; Trusov, V.; Tsakov, I.; Tseepeldorj, B.; Tsurugai, T.; Turcato, M.; Turkot, O.; Turnau, J.; Tymieniecka, T.; Vazquez, M.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vazdik, Y.; Verbytskyi, A.; Viazlo, O.; Vlasov, N.N.; Walczak, R.; Wan Abdullah, W.A.T.; Wegener, D.; Whitmore, J.J.; Wichmann, K.; Wiggers, L.; Wing, M.; Wlasenko, M.; Wolf, G.; Wolfe, H.; Wrona, K.; Wunsch, E.; Yagues-Molina, A.G.; Yamada, S.; Yamazaki, Y.; Yoshida, R.; Youngman, C.; Zabiegalov, O.; Zacek, J.; Zalesak, J.; Zawiejski, L.; Zenaiev, O.; Zeuner, W.; Zhang, Z.; Zhautykov, B.O.; Zhmak, N.; Zhokin, A.; Zichichi, A.; Zlebcik, R.; Zohrabyan, H.; Zolkapli, Z.; Zomer, F.; Zotkin, D.S.; Zarnecki, A.F.

    2012-10-10

    A combination of the inclusive diffractive cross section measurements made by the H1 and ZEUS Collaborations at HERA is presented. The analysis uses samples of diffractive deep inelastic ep scattering data at a centre-of-mass energy sqrt(s) = 318 GeV where leading protons are detected by dedicated spectrometers. Correlations of systematic uncertainties are taken into account, resulting in an improved precision of the cross section measurement which reaches 6% for the most precise points. The combined data cover the range 2.5 < Q2 < 200 GeV2 in photon virtuality, 0.00035 < xIP < 0.09 in proton fractional momentum loss, 0.09 < |t| < 0.55 GeV2 in squared four-momentum transfer at the proton vertex and 0.0018 < beta < 0.816 in beta = x/xIP, where x is the Bjorken scaling variable.

  6. Improving a high-efficiency, gated spectrometer for x-ray Thomson scattering experiments at the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Döppner, T., E-mail: doeppner1@llnl.gov; Bachmann, B.; Emig, J.; Hardy, M.; Kalantar, D. H.; Kritcher, A. L.; Landen, O. L.; Ma, T.; Wood, R. D. [Lawrence Livermore National Laboratory, Livermore, California 94720 (United States); Kraus, D.; Saunders, A. M. [University of California, Berkeley, California 94720 (United States); Neumayer, P. [Gesellschaft für Schwerionenphysik, Darmstadt (Germany); Falcone, R. W. [University of California, Berkeley, California 94720 (United States); Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Fletcher, L. B. [SLAC National Accelerator Laboratory, Menlo Park, California 94720 (United States)

    2016-11-15

    We are developing x-ray Thomson scattering for applications in implosion experiments at the National Ignition Facility. In particular we have designed and fielded MACS, a high-efficiency, gated x-ray spectrometer at 7.5–10 keV [T. Döppner et al., Rev. Sci. Instrum. 85, 11D617 (2014)]. Here we report on two new Bragg crystals based on Highly Oriented Pyrolytic Graphite (HOPG), a flat crystal and a dual-section cylindrically curved crystal. We have performed in situ calibration measurements using a brass foil target, and we used the flat HOPG crystal to measure Mo K-shell emission at 18 keV in 2nd order diffraction. Such high photon energy line emission will be required to penetrate and probe ultra-high-density plasmas or plasmas of mid-Z elements.

  7. An alternative beam line at the U-400 M cyclotron for RIB separation and transport to the FOBOS spectrometer (The technical proposal)

    International Nuclear Information System (INIS)

    Majdikov, V.Z.; Bashevoj, V.V.

    1998-01-01

    The first order ion-optic calculations performed together with the graphical modeling permits us to propose a new variant of the beam-transport line from the backside of the U-400M cyclotron to the FOBOS spectrometer. This beam line could be built in a rather short time without large financial expenditures from available magnetic and vacuum elements. The new beam line could even be considered as an economic alternative to the existing beam line and as a RIB separator. This work is the result of the pre-design R and D aimed to develop the U-400M cyclotron facilities for the RIB experiments performance with the FOBOS spectrometer

  8. State-to-state inelastic and reactive molecular beam scattering from surfaces

    International Nuclear Information System (INIS)

    Lykke, K.R.; Kay, B.D.

    1990-01-01

    Resonantly enhanced multiphoton ionization (REMPI) laser spectroscopic and molecular beam-surface scattering techniques are coupled to study inelastic and reactive gas-surface scattering with state-to-state specificity. Rotational, vibrational, translational and angular distributions have been measured for the inelastic scattering of HCI and N 2 from Au(111). In both cases the scattering is direct-inelastic in nature and exhibits interesting dynamical features such as rotational rainbow scattering. In an effort to elucidate the dynamics of chemical reactions occurring on surfaces we have extended our quantum-resolved scattering studies to include the reactive scattering of a beam of gas phase H-atoms from a chlorinated metal surface M-CI. The nascent rotational and vibrational distributions of the HCI product are determined using REMPI. The thermochemistry for this reaction on Au indicates that the product formation proceeding through chemisorbed H-atoms is slightly endothermic while direct reaction of a has phase H-atom with M-CI is highly exothermic (ca. 50 kcal/mole). Details of the experimental techniques, results and implications regarding the scattering dynamics are discussed. 55 ref., 8 fig

  9. Sensitivity of peak positions to flight-path parameters in a deep-inelastic scattering neutron TOF spectrometer

    International Nuclear Information System (INIS)

    Gray, E.MacA.; Chatzidimitriou-Dreismann, C.A.; Blach, T.P.

    2012-01-01

    The effects of small changes in flight-path parameters (primary and secondary flight paths, detector angles), and of displacement of the sample along the beam axis away from its ideal position, are examined for an inelastic time-of-flight (TOF) neutron spectrometer, emphasising the deep-inelastic regime. The aim was to develop a rational basis for deciding what measured shifts in the positions of spectral peaks could be regarded as reliable in the light of the uncertainties in the calibrated flight-path parameters. Uncertainty in the length of the primary or secondary flight path has the least effect on the positions of the peaks of H, D and He, which are dominated by the accuracy of the calibration of the detector angles. This aspect of the calibration of a TOF spectrometer therefore demands close attention to achieve reliable outcomes where the position of the peaks is of significant scientific interest and is discussed in detail. The corresponding sensitivities of the position of peak of the Compton profile, J(y), to flight-path parameters and sample position are also examined, focusing on the comparability across experiments of results for H, D and He. We show that positioning the sample to within a few mm of the ideal position is required to ensure good comparability between experiments if data from detectors at high forward angles are to be reliably interpreted.

  10. Lise: a recoil spectrometer at GANIL for the production and study of secondary radioactive beams. Present status and future

    International Nuclear Information System (INIS)

    Mueller, A.C.

    1989-01-01

    The doubly achromatic spectrometer LISE, installed at the intermediate-energy heavy-ion facility GANIL is now operating since five years. Essentially, it is composed by two dipole-magnets selecting (in A/Z) and refocusing (achromatically) the projectile-like radioactive fragment-beams emitted at 0 0 . We shall review some of the essential properties of LISE. Some selected examples will be used to demonstrate experimental results which have been obtained so far (discovery of numerous new nuclei up to the drip-lines, half-life measurements, β-γ and delayed-particle spectroscopy, spin-aligned beams, total reaction cross-sections). We shall also discuss several improvements, in particular a cross-field electrostatic/electromagnetic post separator, which are expected to provide in the near future secondary beams of still increased intensity and isotopic purity

  11. Axisymmetric scattering of an acoustical Bessel beam by a rigid fixed spheroid

    OpenAIRE

    Mitri, F. G.

    2015-01-01

    Based on the partial-wave series expansion (PWSE) method in spherical coordinates, a formal analytical solution for the acoustic scattering of a zeroth-order Bessel acoustic beam centered on a rigid fixed (oblate or prolate) spheroid is provided. The unknown scattering coefficients of the spheroid are determined by solving a system of linear equations derived for the Neumann boundary condition. Numerical results for the modulus of the backscattered pressure (\\theta = \\pi) in the near-field an...

  12. Removal of divergences in the problem of scattering of a particle beam by a medium

    International Nuclear Information System (INIS)

    Kuz'min, V.L.

    1977-01-01

    Scattering of a beam of particles (neutrons) by a medium is considered. After the averaging according to the statistical mechanics rules, the cross-section of the process is represented in the form of the series including many-particle distribution functions. The series describes the scattering processes of arbitrary multiplicity. Disconnected parts of the distribution functions give rise to divergences. A method of the re-summation of the original series is proposed, which removes all the divergences completely

  13. Monte Carlo calculation of scattered radiation from applicators in low energy clinical electron beams

    International Nuclear Information System (INIS)

    Jabbari, N.; Hashemi-Malayeri, B.; Farajollahi, A. R.; Kazemnejad, A.

    2007-01-01

    In radiotherapy with electron beams, scattered radiation from an electron applicator influences the dose distribution in the patient. The contribution of this radiation to the patient dose is significant, even in modern accelerators. In most of radiotherapy treatment planning systems, this component is not explicitly included. In addition, the scattered radiation produced by applicators varies based on the applicator design as well as the field size and distance from the applicators. The aim of this study was to calculate the amount of scattered dose contribution from applicators. We also tried to provide an extensive set of calculated data that could be used as input or benchmark data for advanced treatment planning systems that use Monte Carlo algorithms for dose distribution calculations. Electron beams produced by a NEPTUN 10PC medical linac were modeled using the BEAMnrc system. Central axis depth dose curves of the electron beams were measured and calculated, with and without the applicators in place, for different field sizes and energies. The scattered radiation from the applicators was determined by subtracting the central axis depth dose curves obtained without the applicators from that with the applicator. The results of this study indicated that the scattered radiation from the electron applicators of the NEPTUN 10PC is significant and cannot be neglected in advanced treatment planning systems. Furthermore, our results showed that the scattered radiation depends on the field size and decreases almost linearly with depth. (author)

  14. Space shuttle charging or beam-plasma discharge: What can electron spectrometer observations contribute to solving the question?

    International Nuclear Information System (INIS)

    Watermann, J.; Wilhelm, K.; Torkar, K.M.; Riedler, W.

    1988-01-01

    Several cooperative plasma experiments were carried out on board Spacelab-1, the ninth payload of the Space Transportation System (STS-9). Among them, the electron spectrometer 1ES019A was designed to observe 01.-12.5 keV electron fluxes with high temporal and spatial resolution, while the SEPAC electron beam accelerator emitted electron beams with currents up to 280 mA and maximum energies of 5 keV. Since the question of orbiter charging to high voltages has controversially been discussed in several publications on STS-3 and STS-9 electron beam experiments, an attempt is made to relate information from the return electron flux observed during the SEPAC operations to the vehicle charging interpretation. A close examination reveals that most of our observations can be understood if the occurrence of a beam-plasma discharge is assumed at least for electron beam intensities above 100 mA. This would provide a substantial return current capability. High orbiter charging effects during electron beam accelerator electron emissions are consequently not supported by the observations

  15. Performance Assessment of a Plate Beam Splitter for Deep-Ultraviolet Raman Measurements with a Spatial Heterodyne Raman Spectrometer.

    Science.gov (United States)

    Lamsal, Nirmal; Angel, S Michael

    2017-06-01

    In earlier works, we demonstrated a high-resolution spatial heterodyne Raman spectrometer (SHRS) for deep-ultraviolet (UV) Raman measurements, and showed its ability to measure UV light-sensitive compounds using a large laser spot size. We recently modified the SHRS by replacing the cube beam splitter (BS) with a custom plate beam splitter with higher light transmission, an optimized reflectance/transmission ratio, higher surface flatness, and better refractive index homogeneity than the cube beam splitter. Ultraviolet Raman measurements were performed using a SHRS modified to use the plate beam splitter and a matching compensator plate and compared to the previously described cube beam splitter setup. Raman spectra obtained using the modified SHRS exhibit much higher signals and signal-to-noise (S/N) ratio and show fewer spectral artifacts. In this paper, we discuss the plate beam splitter SHRS design features, the advantages over previous designs, and discuss some general SHRS issues such as spectral bandwidth, S/N ratio characteristics, and optical efficiency.

  16. Observation of second harmonics in laser-electron scattering using low energy electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Iinuma, Masataka [ADSM, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8530 (Japan)]. E-mail: iinuma@hiroshima-u.ac.jp; Matsukado, Koji [Venture Business Laboratory, Hiroshima University, 1-313 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8527 (Japan); Endo, Ichita [ADSM, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8530 (Japan); Hashida, Masaki [Institute for chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Hayashi, Kenji [ADSM, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8530 (Japan); Kohara, Akitsugu [ADSM, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8530 (Japan); Matsumoto, Fumihiko [ADSM, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8530 (Japan); Nakanishi, Yoshitaka [ADSM, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8530 (Japan); Sakabe, Shuji [Institute for chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Shimizu, Seiji [Institute for chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Tauchi, Toshiaki [High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Yamamoto, Ken [ADSM, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8530 (Japan); Takahashi, Tohru [ADSM, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8530 (Japan)

    2005-10-17

    We observed photon generation in the second harmonic region in collisions of 10 keV free electrons and the intense laser beam with the peak intensity of 4.0x10{sup 15} W/cm{sup 2}. Observed photon yield was 3 orders of magnitude higher than expectation from the nonlinear Compton scattering. The observation indicates necessity of further investigation for the interaction between the intense laser field and the low energy electron beam.

  17. Use of a free-jet expansion, molecular beam mass spectrometer to understand processes involving volatile corrosion products

    International Nuclear Information System (INIS)

    Jacobson, N.S.

    1997-01-01

    Many high-temperature corrosion processes generate volatile products in addition to condensed phase products. Examples of these volatile products are chlorides, oxychlorides, and certain oxides and hydroxyl species. One of the best techniques to identify high temperature vapor molecules is mass spectrometry. Most mass spectrometers operate in high vacuum and are generally used to examine processes ocurring at greatly reduced pressures. However, a free-jet expansion, molecular beam mass spectrometer system allows direct sampling of volatile corrosion products. This instrument is described. Several examples from our studies on chlorination/oxidation of metals and ceramics are discussed. In addition, reactions of Cr 2 O 3 , SiO 2 , and Al 2 O 3 with water vapor, which produce volatile hydroxyl species are discussed. (orig.)

  18. 2D scattering of unpolarized beams of electrons by charged nanomagnets

    Energy Technology Data Exchange (ETDEWEB)

    Senbeta, Teshome, E-mail: teshearada@yahoo.com [Department of Physics, Addis Ababa University, P.O. Box 1176, Addis Ababa (Ethiopia); Mal' nev, V.N., E-mail: vnmalnev@aau.edu.et [Department of Physics, Addis Ababa University, P.O. Box 1176, Addis Ababa (Ethiopia)

    2012-07-15

    2D spin-dependent scattering of slow unpolarized beams of electrons by charged nanomagnets is analyzed in the Born approximation. The obtained scattering lengths are larger than those from the neutral nanomagnets approximately by one order. It is shown that for particular parameters of the system it is possible to polarize completely the scattered electrons in a narrow range of scattering angles. The most suitable system for realization of these effects is 2D Si electron gas with immersed nanomagnets. - Highlights: Black-Right-Pointing-Pointer We study 2D spin dependent electron scattering by charged nanomagnets. Black-Right-Pointing-Pointer The applicability of the Born approximation to the problem is discussed. Black-Right-Pointing-Pointer Unpolarized incident beams used to obtain completely polarized scattered electrons. Black-Right-Pointing-Pointer The study shows peculiarities of 2D spin dependent scattering enhanced by Coulomb potential. Black-Right-Pointing-Pointer The result obtained can be used as one method of controlling spin currents.

  19. Hybrid simulation of scatter intensity in industrial cone-beam computed tomography

    International Nuclear Information System (INIS)

    Thierry, R.; Miceli, A.; Hofmann, J.; Flisch, A.; Sennhauser, U.

    2009-01-01

    A cone-beam computed tomography (CT) system using a 450 kV X-ray tube has been developed to challenge the three-dimensional imaging of parts of the automotive industry in short acquisition time. Because the probability of detecting scattered photons is high regarding the energy range and the area of detection, a scattering correction becomes mandatory for generating reliable images with enhanced contrast detectability. In this paper, we present a hybrid simulator for the fast and accurate calculation of the scattering intensity distribution. The full acquisition chain, from the generation of a polyenergetic photon beam, its interaction with the scanned object and the energy deposit in the detector is simulated. Object phantoms can be spatially described in form of voxels, mathematical primitives or CAD models. Uncollided radiation is treated with a ray-tracing method and scattered radiation is split into single and multiple scattering. The single scattering is calculated with a deterministic approach accelerated with a forced detection method. The residual noisy signal is subsequently deconvoluted with the iterative Richardson-Lucy method. Finally the multiple scattering is addressed with a coarse Monte Carlo (MC) simulation. The proposed hybrid method has been validated on aluminium phantoms with varying size and object-to-detector distance, and found in good agreement with the MC code Geant4. The acceleration achieved by the hybrid method over the standard MC on a single projection is approximately of three orders of magnitude.

  20. Calibration and energy resolution study of a high dispersive power Thomson Parabola Spectrometer with monochromatic proton beams

    International Nuclear Information System (INIS)

    Schillaci, F.; Cirrone, G.A.P.; Cuttone, G.; Pisciotta, P.; Rifuggiato, D.; Romano, F.; Scuderi, V.; Stancampiano, C.; Tramontana, A.; Amato, A.; Caruso, G.F.; Salamone, S.; Maggiore, M.; Velyhan, A.; Margarone, D.; Palumbo, G. Parasiliti; Russo, G.

    2014-01-01

    A high energy resolution, high dispersive power Thomson Parabola Spectrometer has been developed at INFN-LNS in order to characterize laser-driven beams up to 30- 40 MeV for protons. This device has parallel electric and magnetic field to deflect particles of a certain charge-to-mass ratio onto parabolic traces on the detection plane. Calibration of the deflection sector is crucial for data analysis, namely energy determination of analysed beam, and to evaluate the effective energy limit and resolution. This work reports the study of monochromatic proton beams delivered by the TANDEM accelerator at LNS (Catania) in the energy range between 6 and 12.5 MeV analysed with our spectrometer which allows a precise characterization of the electric and magnetic deflections. Also the energy and the Q/A resolutions and the energy limits have been evaluated proposing a mathematical model that can be used for data analysis, for the experimental set up and for the device scalability for higher energy

  1. Extending backward polygon beam tracing to glossy scattering surfaces

    CSIR Research Space (South Africa)

    Duvenhage, B

    2011-05-01

    Full Text Available to render caustics that could not otherwise be sim- ulated efficiently using the high fidelity forward raytracing and radiosity rendering techniques of the time. Similar to what Heckbert and Hanrahan proposed, Watt [Wat90] used backward polygon beam....: Adaptive radiosity textures for bidi- rectional ray tracing. In SIGGRAPH ?90: Proceedings of the 17th Annual Conference on Computer graphics and Interactive Techniques (New York, NY, USA, 1990), ACM Press, New York, pp. 145?154. [HH84] HECKBERT P. S...

  2. Electron beam final focus system for Thomson scattering at ELBE

    Energy Technology Data Exchange (ETDEWEB)

    Krämer, J.M., E-mail: jmkr@danfysik.dk [Danfysik A/S, Gregersensvej 8, 2630 Taastrup (Denmark); Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, Bautzner Landstrasse 400, 01328 Dresden (Germany); Technische Universität Dresden, 01069 Dresden (Germany); Budde, M.; Bødker, F. [Danfysik A/S, Gregersensvej 8, 2630 Taastrup (Denmark); Irman, A.; Jochmann, A. [Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, Bautzner Landstrasse 400, 01328 Dresden (Germany); Kristensen, J.P. [Danfysik A/S, Gregersensvej 8, 2630 Taastrup (Denmark); Lehnert, U.; Michel, P. [Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, Bautzner Landstrasse 400, 01328 Dresden (Germany); Schramm, U. [Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, Bautzner Landstrasse 400, 01328 Dresden (Germany); Technische Universität Dresden, 01069 Dresden (Germany)

    2016-09-11

    The design of an electron beam final focus system (FFS) aiming for high-flux laser-Thomson backscattering X-ray sources at ELBE is presented. A telescope system consisting of four permanent magnet based quadrupoles was found to have significantly less chromatic aberrations than a quadrupole doublet or triplet as commonly used. Focusing properties like the position of the focal plane and the spot size are retained for electron beam energies between 20 and 30 MeV by adjusting the position of the quadrupoles individually on a motorized stage. The desired ultra-short electron bunches require an increased relative energy spread up to a few percent and, thus, second order chromatic effects must be taken into account. We also present the design and test results of the permanent magnet quadrupoles. Adjustable shunts allow for correction of the field strength and compensation of deviations in the permanent magnet material. For a beam emittance of 13 mm mrad, we predict focal spot sizes of about 40 μm (rms) and divergences of about 10 mrad using the FFS.

  3. Electron beam final focus system for Thomson scattering at ELBE

    CERN Document Server

    Krämer, J.M.; Bødker, F.; Irman, A.; .Jochmann A.; Kristensen, J.P.; Lehnert U., HZDR; Michel, P.; Schrammb, U.; 10.1016/j.nima.2015.10.067

    2016-01-01

    The design of an electron beam final focus system (FFS) aiming for high-flux laser-Thomson backscattering X-ray sources at ELBE is presented. A telescope system consisting of four permanent magnet based quadrupoles was found to have significantly less chromatic aberrations than a quadrupole doublet or triplet as commonly used. Focusing properties like the position of the focal plane and the spot size are retained for electron beam energies between 20 and 30 MeV by adjusting the position of the quadrupoles individually on a motorized stage. The desired ultra-short electron bunches require an increased relative energy spread up to a few percent and, thus, second order chromatic effects must be taken into account. We also present the design and test results of the permanent magnet quadrupoles. Adjustable shunts allow for correction of the field strength and compensation of deviations in the permanent magnet material. For a beam emittance of 13 mm mrad, we predict focal spot sizes of about 40 μm (rms) and diverg...

  4. Electron Beam Final Focus System For Thomson Scattering At Elbe

    CERN Document Server

    Krämer, J.M.; Bødkera, F.; Irman, A.; Jochmann, A.; Kristensena, J.P.; Lehnert, U.; Michel, P.; Schramm, U.; 10.1016/j.nima.2015.10.067

    2016-01-01

    The design of an electron beam final focus system (FFS) aiming for high-flux laser-Thomson backscattering X-ray sources at ELBE is presented. A telescope system consisting of four permanent magnet based quadrupoles was found to have significantly less chromatic aberrations than a quadrupole doublet or triplet as commonly used. Focusing properties like the position of the focal plane and the spot size are retained for electron beam energies between 20 and 30 MeV by adjusting the position of the quadrupoles individually on a motorized stage. The desired ultra-short electron bunches require an increased relative energy spread up to a few percent and, thus, second order chromatic effects must be taken into account. We also present the design and test results of the permanent magnet quadrupoles. Adjustable shunts allow for correction of the field strength and compensation of deviations in the permanent magnet material. For a beam emittance of 13 mm mrad, we predict focal spot sizes of about 40 μm (rms) and diverg...

  5. Quasielastic nucleon scattering using polarized beams and targets

    International Nuclear Information System (INIS)

    Haeusser, O.

    1990-07-01

    Inelastic scattering of polarized intermediate energy nucleons to continuum nuclear states is discussed with emphasis on recent results. Spin momentum correlations of protons in polarized targets of 3 He were observed for the first time. Complete spin observables in (p,p') show effects of the nuclear spin-isospin response and of an NN interaction modified by the nuclear medium. A comparison of Gamow Teller and isovector M1 giant resonance strengths in the sd shell provides evidence for large meson exchange current effects in the M1. (Author) (37 refs., 2 tabs., 9 figs.)

  6. MICROBUNCH TEMPORAL DIAGNOSTIC BY COMPTON SCATTERING IN INTERFERING LASER BEAMS

    International Nuclear Information System (INIS)

    AMATUNI, A.TS.; POGORELSKY, I.V.

    1998-01-01

    The exact solution of the classical nonlinear equation of motion for a relativistic electron in the field of two electromagnetic (EM) waves is obtained. For the particular case of the linearly polarized standing EM wave in the planar optical cavity, the intensity of the nonlinear Compton scattering, the time of flight, and the momentum variation after the relativistic electron passes along the cavity axis are calculated in weak and strong field limits. The extent of these effects depends on the initial phase of the EM wave when the electron enters the cavity. This can be used for the production, diagnosis, and acceleration of relativistic electron (positron) microbunches

  7. Intermediate PT jet spectrometers

    International Nuclear Information System (INIS)

    Gutay, L.J.; Koltick, D.; Hauptman, J.; Stork, D.; Theodosiou, G.

    1988-01-01

    A design is presented for a limited solid angle, high resolution double arm spectrometer at 90 degree to the begin, with a vertex detector and particle identification in both arms. The jet arm is designed to accept a complete jet, and identify its substructure of sub-jets, hadrons, and leptons. The particle arm would measure e,π,K,p ratios for P T 0 to the beam for the purpose of tagging Higgs production by boson fusion, 1 gauge boson (WW, ZZ, and WZ) scattering 2 L, and other processes involving the interactions of virtual gauge bosons

  8. Measuring module of spectrometer of neutron small angle scattering on the IBR pulse reactor

    International Nuclear Information System (INIS)

    Vagov, V.A.; Zhukov, G.P.; Kozlova, E.P.; Korobchenko, M.L.; Namsraj, Yu.; Ostanevich, Yu.M.; Savvateev, A.S.; Salamatin, I.M.; Sirotin, A.P.

    1980-01-01

    Equipment and software for experiments with neutron small angle scattering is described. It is intended for data acquisition, equipment control storage of collected data and their output to network of the Laboratory measuring centre. The set-up equipment includes: 9 neutron detectors with corresponding electronic apparatus, sample exchanging device, communication link, SM-3 type minicomputer of an extended configuration and some units of CAMAC electronic equipment. The software (MUR applied operatio system) is intended for the automatic performance of the given number of cycles of successive uniform runs of a given duration with the sample list at two possible filter positions. Besides, the MUR system contains test, debugging and service software. The software has been designed using the SANPO system means [ru

  9. Beam energy spread in FERMI(at)elettra gun and linac induced by intrabeam scattering

    International Nuclear Information System (INIS)

    Zholents, Alexander A; Zholents, Alexander A; Zolotorev, Max S.; Penco, Giuseppe

    2008-01-01

    Intrabeam scattering (IBS) of electrons in the pre-cathode area in the electron guns know in the literature as Boersh effect is responsible for a growth of the electron beam energy spread there. Albeit most visible within the electron gun where the electron beam density is large and the energy spread is small, the IBS acts all along the entire electron beam pass through the Linac. In this report we calculate the energy spread induced by IBS in the FERMI(at)elettra electron gun

  10. Description of the double Compton spectrometer at Mayence MPI

    International Nuclear Information System (INIS)

    Borchert, H.; Ziegler, B.; Gimm, H.; Zieger, A.; Hughes, R.J.; Ahrens, J.

    1977-01-01

    The double Compton spectrometer of the Laboratories of the Mayence Linear Accelerator consists in two identical magnetic spectrometers, in which the electron scattered forwards by photons through a Compton process, are detected. The spectrometers have been built to detect 10-350 MeV photons and, as they involve thin Compton targets, their effect on the photon flux is negligible. They are put in cascade inside a well collimated bremsstrahlung beam. A thick absorbing target (max. thickness 2m) can be inserted inside the beam. The facility is outlined, some special properties of the accelerator and the bremsstrahlung beam are given. The properties of a Compton spectrometer involving eleven detectors are given by eleven response functions giving the relations between the photon flux impinging the Compton target and the counting rates of the detectors for a given adjustment of the magnets. A Monte-Carlo method is used for the calculation together with analytical methods neglecting the multiple scattering effects [fr

  11. Large-angle adjustable coherent atomic beam splitter by Bragg scattering

    NARCIS (Netherlands)

    Koolen, A.E.A.; Jansen, G.T.; Domen, K.F.E.M.; Beijerinck, H.C.W.; Leeuwen, van K.A.H.

    2002-01-01

    Using a "monochromatic" (single-axial-velocity) and slow (250 m/s) beam of metastable helium atoms, we realize up to eighth-order Bragg scattering and obtain a splitting angle of 6 mrad at low laser power (3 mW). This corresponds to a truly macroscopic separation of 12 mm on the detector. For

  12. Electromagnetic scattering of a vector Bessel beam in the presence of an impedance cone

    KAUST Repository

    Salem, Mohamed; Bagci, Hakan

    2013-01-01

    The electromagnetic field scattering of a vector Bessel beam in the presence of an infinite circular cone with an impedance boundary on its surface is considered. The impinging field is normal to the tip of the cone and is expanded in terms

  13. Dynamics of chemical reactions of multiply-charged cations: Information from beam scattering experiments

    Czech Academy of Sciences Publication Activity Database

    Herman, Zdeněk

    2015-01-01

    Roč. 378, FEB 2015 (2015), s. 113-126 ISSN 1387-3806 Institutional support: RVO:61388955 Keywords : Multiply-charged ions * Dynamics of chemical reactions * Beam scattering Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.183, year: 2015

  14. Angle-Beam Shear Wave Scattering from Buried Crack-like Defects in Bonded Specimens (Postprint)

    Science.gov (United States)

    2017-02-01

    defects: such as understanding the scattering behavior of fatigue cracks emanating from fastener holes in aluminum structural components [2]. Angle...Ultrasonic NDE techniques using angle-beam wedges coupled to PZT transducers have also been utilized in measuring the depth of surface-breaking cracks

  15. Electromagnetic scattering by a uniaxial anisotropic sphere located in an off-axis Bessel beam.

    Science.gov (United States)

    Qu, Tan; Wu, Zhen-Sen; Shang, Qing-Chao; Li, Zheng-Jun; Bai, Lu

    2013-08-01

    Electromagnetic scattering of a zero-order Bessel beam by an anisotropic spherical particle in the off-axis configuration is investigated. Based on the spherical vector wave functions, the expansion expression of the zero-order Bessel beam is derived, and its convergence is numerically discussed in detail. Utilizing the tangential continuity of the electromagnetic fields, the expressions of scattering coefficients are given. The effects of the conical angle of the wave vector components of the zero-order Bessel beam, the ratio of the radius of the sphere to the central spot radius of the zero-order Bessel beam, the shift of the beam waist center position along both the x and y axes, the permittivity and permeability tensor elements, and the loss of the sphere on the radar cross section (RCS) are numerically analyzed. It is revealed that the maximum RCS appears in the conical direction or neighboring direction when the sphere is illuminated by a zero-order Bessel beam. Furthermore, the RCS will decrease and the symmetry is broken with the shift of the beam waist center.

  16. Ultrafast cone-beam CT scatter correction with GPU-based Monte Carlo simulation

    Directory of Open Access Journals (Sweden)

    Yuan Xu

    2014-03-01

    Full Text Available Purpose: Scatter artifacts severely degrade image quality of cone-beam CT (CBCT. We present an ultrafast scatter correction framework by using GPU-based Monte Carlo (MC simulation and prior patient CT image, aiming at automatically finish the whole process including both scatter correction and reconstruction within 30 seconds.Methods: The method consists of six steps: 1 FDK reconstruction using raw projection data; 2 Rigid Registration of planning CT to the FDK results; 3 MC scatter calculation at sparse view angles using the planning CT; 4 Interpolation of the calculated scatter signals to other angles; 5 Removal of scatter from the raw projections; 6 FDK reconstruction using the scatter-corrected projections. In addition to using GPU to accelerate MC photon simulations, we also use a small number of photons and a down-sampled CT image in simulation to further reduce computation time. A novel denoising algorithm is used to eliminate MC noise from the simulated scatter images caused by low photon numbers. The method is validated on one simulated head-and-neck case with 364 projection angles.Results: We have examined variation of the scatter signal among projection angles using Fourier analysis. It is found that scatter images at 31 angles are sufficient to restore those at all angles with < 0.1% error. For the simulated patient case with a resolution of 512 × 512 × 100, we simulated 5 × 106 photons per angle. The total computation time is 20.52 seconds on a Nvidia GTX Titan GPU, and the time at each step is 2.53, 0.64, 14.78, 0.13, 0.19, and 2.25 seconds, respectively. The scatter-induced shading/cupping artifacts are substantially reduced, and the average HU error of a region-of-interest is reduced from 75.9 to 19.0 HU.Conclusion: A practical ultrafast MC-based CBCT scatter correction scheme is developed. It accomplished the whole procedure of scatter correction and reconstruction within 30 seconds.----------------------------Cite this

  17. A FDTD solution of scattering of laser beam with orbital angular momentum by dielectric particles: Far-field characteristics

    International Nuclear Information System (INIS)

    Sun, Wenbo; Hu, Yongxiang; Weimer, Carl; Ayers, Kirk; Baize, Rosemary R.; Lee, Tsengdar

    2017-01-01

    Electromagnetic (EM) beams with orbital angular momentum (OAM) may have great potential applications in communication technology and in remote sensing of the Earth-atmosphere system and outer planets. Study of their interaction with optical lenses and dielectric or metallic objects, or scattering of them by particles in the Earth-atmosphere system, is a necessary step to explore the advantage of the OAM EM beams. In this study, the 3-dimensional (3D) scattered-field (SF) finite-difference time domain (FDTD) technique with the convolutional perfectly matched layer (CPML) absorbing boundary conditions (ABC) is applied to calculate the scattering of the purely azimuthal (the radial mode number is assumed to be zero) Laguerre–Gaussian (LG) beams with the OAM by dielectric particles. We found that for OAM beam's interaction with dielectric particles, the forward-scattering peak in the conventional phase function (P11) disappears, and light scattering peak occurs at a scattering angle of ~15° to 45°. The disappearance of forward-scattering peak means that, in laser communications most of the particle-scattered noise cannot enter the receiver, thus the received light is optimally the original OAM-encoded signal. This feature of the OAM beam also implies that in lidar remote sensing of the atmospheric particulates, most of the multiple-scattering energy will be off lidar sensors, and this may result in an accurate profiling of particle layers in the atmosphere or in the oceans by lidar, or even in the ground when a ground penetration radar (GPR) with the OAM is applied. This far-field characteristics of the scattered OAM light also imply that the optical theorem, which is derived from plane-parallel wave scattering case and relates the forward scattering amplitude to the total cross section of the scatterer, is invalid for the scattering of OAM beams by dielectric particles. - Highlights: • Scattering of orbital angular momentum (OAM) laser beam by dielectric

  18. Comparison of surface doses from spot scanning and passively scattered proton therapy beams

    International Nuclear Information System (INIS)

    Arjomandy, Bijan; Sahoo, Narayan; Gillin, Michael; Cox, James; Lee, Andrew

    2009-01-01

    Proton therapy for the treatment of cancer is delivered using either passively scattered or scanning beams. Each technique delivers a different amount of dose to the skin, because of the specific feature of their delivery system. The amount of dose delivered to the skin can play an important role in choosing the delivery technique for a specific site. To assess the differences in skin doses, we measured the surface doses associated with these two techniques. For the purpose of this investigation, the surface doses in a phantom were measured for ten prostate treatment fields planned with passively scattered proton beams and ten patients planned with spot scanning proton beams. The measured doses were compared to evaluate the differences in the amount of skin dose delivered by using these techniques. The results indicate that, on average, the patients treated with spot scanning proton beams received lower skin doses by an amount of 11.8% ± 0.3% than did the patients treated with passively scattered proton beams. That difference could amount to 4 CGE per field for a prescribed dose of 76 CGE in 38 fractions treated with two equally weighted parallel opposed fields. (note)

  19. Kernel integration scatter model for parallel beam gamma camera and SPECT point source response

    International Nuclear Information System (INIS)

    Marinkovic, P.M.

    2001-01-01

    Scatter correction is a prerequisite for quantitative single photon emission computed tomography (SPECT). In this paper a kernel integration scatter Scatter correction is a prerequisite for quantitative SPECT. In this paper a kernel integration scatter model for parallel beam gamma camera and SPECT point source response based on Klein-Nishina formula is proposed. This method models primary photon distribution as well as first Compton scattering. It also includes a correction for multiple scattering by applying a point isotropic single medium buildup factor for the path segment between the point of scatter an the point of detection. Gamma ray attenuation in the object of imaging, based on known μ-map distribution, is considered too. Intrinsic spatial resolution of the camera is approximated by a simple Gaussian function. Collimator is modeled simply using acceptance angles derived from the physical dimensions of the collimator. Any gamma rays satisfying this angle were passed through the collimator to the crystal. Septal penetration and scatter in the collimator were not included in the model. The method was validated by comparison with Monte Carlo MCNP-4a numerical phantom simulation and excellent results were obtained. The physical phantom experiments, to confirm this method, are planed to be done. (author)

  20. Pitch Angle Scattering of Upgoing Electron Beams in Jupiter's Polar Regions by Whistler Mode Waves

    Science.gov (United States)

    Elliott, S. S.; Gurnett, D. A.; Kurth, W. S.; Clark, G.; Mauk, B. H.; Bolton, S. J.; Connerney, J. E. P.; Levin, S. M.

    2018-02-01

    The Juno spacecraft's Jupiter Energetic-particle Detector Instrument has observed field-aligned, unidirectional (upgoing) electron beams throughout most of Jupiter's entire polar cap region. The Waves instrument detected intense broadband whistler mode emissions occurring in the same region. In this paper, we investigate the pitch angle scattering of the upgoing electron beams due to interactions with the whistler mode waves. Profiles of intensity versus pitch angle for electron beams ranging from 2.53 to 7.22 Jovian radii show inconsistencies with the expected adiabatic invariant motion of the electrons. It is believed that the observed whistler mode waves perturb the electron motion and scatter them away from the magnetic field line. The diffusion equation has been solved by using diffusion coefficients which depend on the magnetic intensity of the whistler mode waves.

  1. Beam-helicity asymmetry arising from deeply virtual Compton scattering measured with kinematically complete event reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Airapetian, A. [Giessen Univ. (Germany). Physikalisches Inst.; Michigan Univ., Ann Arbor, MI (United States). Randall Lab. of Physics; Akopov, N. [Yerevan Physics Inst. (Armenia); Akopov, Z. [DESY, Hamburg (DE)] (and others)

    2012-06-15

    The beam-helicity asymmetry in exclusive electroproduction of real photons by the longitudinally polarized HERA positron beam scattering off an unpolarized hydrogen target is measured at HERMES. The asymmetry arises from deeply virtual Compton scattering and its interference with the Bethe-Heitler process. Azimuthal amplitudes of the beam-helicity asymmetry are extracted from a data sample consisting of ep{yields}ep{gamma} events with detection of all particles in the final state including the recoiling proton. The installation of a recoil detector, while reducing the acceptance of the experiment, allows the elimination of resonant background that was estimated to contribute an average of about 12% to the signal in previous HERMES publications. The removal of the resonant background from the present data sample is shown to increase the magnitude of the leading asymmetry amplitude by 0.054{+-}0.016 to -0.328{+-}0.027(stat.){+-}0.045(syst.).

  2. Beam-helicity asymmetry arising from deeply virtual Compton scattering measured with kinematically complete event reconstruction

    International Nuclear Information System (INIS)

    Airapetian, A.; Akopov, Z.

    2012-06-01

    The beam-helicity asymmetry in exclusive electroproduction of real photons by the longitudinally polarized HERA positron beam scattering off an unpolarized hydrogen target is measured at HERMES. The asymmetry arises from deeply virtual Compton scattering and its interference with the Bethe-Heitler process. Azimuthal amplitudes of the beam-helicity asymmetry are extracted from a data sample consisting of ep→epγ events with detection of all particles in the final state including the recoiling proton. The installation of a recoil detector, while reducing the acceptance of the experiment, allows the elimination of resonant background that was estimated to contribute an average of about 12% to the signal in previous HERMES publications. The removal of the resonant background from the present data sample is shown to increase the magnitude of the leading asymmetry amplitude by 0.054±0.016 to -0.328±0.027(stat.)±0.045(syst.).

  3. Impact of beam ions on α-particle measurements by collective Thomson scattering in ITER

    DEFF Research Database (Denmark)

    Egedal, J.; Bindslev, H.; Budny, R.V.

    2005-01-01

    Collective Thomson scattering (CTS) has been proposed as a viable diagnostic for characterizing fusion born a-distributions in ITER. However, the velocities of the planned 1 MeV deuterium heating beam ions in 1TER are similar to that of fusion born a-particles and may therefore mask the measureme......Collective Thomson scattering (CTS) has been proposed as a viable diagnostic for characterizing fusion born a-distributions in ITER. However, the velocities of the planned 1 MeV deuterium heating beam ions in 1TER are similar to that of fusion born a-particles and may therefore mask...... and the alpha-particles are calculated. Our investigations show that the CTS measurements of alpha-particles will not be masked by the presence of the beam ions in H-mode plasmas. In lower density reversed shear plasmas, only a part of the CTS alpha-particle spectrum will be perturbed....

  4. Characterization of biomass burning aerosols produced in the laboratory with a light-scattering aerosol mass spectrometer

    Science.gov (United States)

    Middlebrook, A. M.; Adler, G. A.; Coggon, M.; De Gouw, J. A.; Franchin, A.; Gilman, J.; Koss, A.; Krechmer, J. E.; Lamb, K.; Manfred, K.; Roberts, J. M.; Schwarz, J. P.; Sekimoto, K.; Selimovic, V.; Stockwell, C.; Wagner, N.; Warneke, C.; Washenfelder, R. A.; Womack, C.; Yokelson, R. J.; Yuan, B.

    2017-12-01

    During the 2016 NOAA FIREX project at the Missoula Fire Sciences Laboratory, small fires of known fuel type and properties were ignited to characterize their direct emissions with a large variety of new sampling methods. Two types of experiments were employed: sampling smoke directly from the exhaust stack throughout the lifecycle of the fires (stack burns) or sampling when the exhaust vent was closed to fill the room with smoke (room burns). For both types of burns, photo-oxidation chambers were at times used to mimic aging in the atmosphere. During all these experiments, we measured the non-refractory components of the smoke particles using an Aerodyne compact time-of-flight aerosol mass spectrometer (AMS) with a light scattering module and diluted the sample line as little as possible (usually by a factor of 10) without overwhelming our instrument. For the stack burns, our AMS was placed near the top of the exhaust stack to capture the composition and size distribution during the rapidly changing stages of the fires. We found that the chemical composition of the aerosols varied with fuel type and combustion conditions on time scales of a few minutes as the fuels went through different stages of heating and combustion. For the room burns, we obtained additional measurements with the light-scattering module aimed at understanding how well smoke particles are measured with the AMS, along with characterization of their physical properties. We will present a summary of our results, with connections to their relevance for constraining model treatments of fire emissions on the atmosphere.

  5. Present status of the low energy linac-based slow positron beam and positronium spectrometer in Saclay

    Science.gov (United States)

    Liszkay, L.; Comini, P.; Corbel, C.; Debu, P.; Grandemange, P.; Pérez, P.; Rey, J.-M.; Reymond, J.-M.; Ruiz, N.; Sacquin, Y.; Vallage, B.

    2014-04-01

    A new slow positron beamline featuring a large acceptance positronium lifetime spectrometer has been constructed and tested at the linac-based slow positron source at IRFU CEA Saclay, France. The new instrument will be used in the development of a dense positronium target cloud for the GBAR experiment. The GBAR project aims at precise measurement of the gravitational acceleration of antihydrogen in the gravitational field of the Earth. Beyond application in fundamental science, the positron spectrometer will be used in materials research, for testing thin porous films and layers by means of positronium annihilation. The slow positron beamline is being used as a test bench to develop further instrumentation for positron annihilation spectroscopy (Ps time-of-flight, pulsed positron beam). The positron source is built on a low energy linear electron accelerator (linac). The 4.3 MeV electron energy used is well below the photoneutron threshold, making the source a genuine on-off device, without remaining radioactivity. The spectrometer features large BGO (Bismuth Germanate) scintillator detectors, with sufficiently large acceptance to detect all ortho-positronium annihilation lifetime components (annihilation in vacuum and in nanopores).

  6. A FDTD solution of scattering of laser beam with orbital angular momentum by dielectric particles: Far-field characteristics

    Science.gov (United States)

    Sun, Wenbo; Hu, Yongxiang; Weimer, Carl; Ayers, Kirk; Baize, Rosemary R.; Lee, Tsengdar

    2017-02-01

    Electromagnetic (EM) beams with orbital angular momentum (OAM) may have great potential applications in communication technology and in remote sensing of the Earth-atmosphere system and outer planets. Study of their interaction with optical lenses and dielectric or metallic objects, or scattering of them by particles in the Earth-atmosphere system, is a necessary step to explore the advantage of the OAM EM beams. In this study, the 3-dimensional (3D) scattered-field (SF) finite-difference time domain (FDTD) technique with the convolutional perfectly matched layer (CPML) absorbing boundary conditions (ABC) is applied to calculate the scattering of the purely azimuthal (the radial mode number is assumed to be zero) Laguerre-Gaussian (LG) beams with the OAM by dielectric particles. We found that for OAM beam's interaction with dielectric particles, the forward-scattering peak in the conventional phase function (P11) disappears, and light scattering peak occurs at a scattering angle of 15° to 45°. The disappearance of forward-scattering peak means that, in laser communications most of the particle-scattered noise cannot enter the receiver, thus the received light is optimally the original OAM-encoded signal. This feature of the OAM beam also implies that in lidar remote sensing of the atmospheric particulates, most of the multiple-scattering energy will be off lidar sensors, and this may result in an accurate profiling of particle layers in the atmosphere or in the oceans by lidar, or even in the ground when a ground penetration radar (GPR) with the OAM is applied. This far-field characteristics of the scattered OAM light also imply that the optical theorem, which is derived from plane-parallel wave scattering case and relates the forward scattering amplitude to the total cross section of the scatterer, is invalid for the scattering of OAM beams by dielectric particles.

  7. Combined inclusive diffractive cross sections measured with foreward proton spectrometers in deep inelastic ep scattering at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Aaron, F.D. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Bucharest Univ. (Romania). Faculty of Physics; Abramowicz, H. [Tel Aviv Univ. (Israel). School of Physics; Max Planck Institute for Physics, Munich (Germany); Abt, I. [Max Planck Institute for Physics, Munich (DE)] (and others)

    2012-07-15

    A combination of the inclusive diffractive cross section measurements made by the H1 and ZEUS Collaborations at HERA is presented. The analysis uses samples of diffractive deep inelastic ep scattering data at a centre-of-mass energy {radical}(s)=318 GeV where leading protons are detected by dedicated spectrometers. Correlations of systematic uncertainties are taken into account, resulting in an improved precision of the cross section measurement which reaches 6% for the most precise points. The combined data cover the range 2.5

  8. Study of two-charged body hadronic scattering, induced on protons by a beam of π-, K-, antip, between 3 and 12 GeV/c, wih a scattering angle near 900 c.m

    International Nuclear Information System (INIS)

    Billoir, P.

    1983-02-01

    Large angle two-body hadronic scattering was studied between 3 and 12 GeV/c by the WA 13 experiment at C.E.R.N. (Omega Spectrometer), with a negative RF separated beam, on a hydrogen target. The cross sections of these reactions, at fixed c.m. angle, decrease very rapidly with the energy; then high beam intensities were required together with high selectivity, obtained thanks to a multilevel triggering system, including a coplanarity chamber associated to a fast logic. This thesis describes the reactions with two charged final particles (π - p, K - p, antipp elastic scattering and antipp annihilation into two mesons). The kinematical reconstruction eliminates the background almost completely. More over a special vertex fitting method improves the reconstruction of the tracks, using their convergence at the same point to increase the geometrical information. Neglecting fixed t structures, the differential cross sections are compatible with the dimensional counting laws (however elastic antipp seems to decrease less rapidly than expected). Different models are compared with the results: no one agrees with the whole set of available data. This work emphasizes the handling of error matrices and the use of optimal estimation. It proposes a recursive track fitting method, optimized with respect to the multiple scattering [fr

  9. Effect of laser beam filamentation on plasma wave localization and stimulated Raman scattering

    International Nuclear Information System (INIS)

    Purohit, Gunjan; Sharma, R. P.

    2013-01-01

    This paper presents the effect of laser beam filamentation on the localization of electron plasma wave (EPW) and stimulated Raman scattering (SRS) in unmagnitized plasma when both relativistic and ponderomotive nonlinearities are operative. The filamentary dynamics of laser beam is studied and the splitted profile of the laser beam is obtained due to uneven focusing of the off-axial rays. The localization of electron plasma wave takes place due to nonlinear coupling between the laser beam and EPW. Stimulated Raman scattering of this EPW is studied and backreflectivity has been calculated. The localization of EPW also affects the eigenfrequency and damping of plasma wave; consequently, mismatch and modified enhanced Landau damping lead to the disruption of SRS process and a substantial reduction in the backreflectivity. The new enhanced damping of the plasma wave has been calculated and it is found that the SRS process gets suppressed due to the localization of plasma wave in laser beam filamentary structures. For typical laser beam and plasma parameters with wavelength λ (=1064 nm), power flux (=10 16 W/cm 2 ) and plasma density (n/n cr ) = 0.2; the SRS back reflectivity is found to be suppressed by a factor of around 5%. (author)

  10. Calibration of the OHREX high-resolution imaging crystal spectrometer at the Livermore electron beam ion traps

    Energy Technology Data Exchange (ETDEWEB)

    Hell, N. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Dr. Remeis-Sternwarte and ECAP, Universität Erlangen-Nürnberg, Bamberg 96049 (Germany); Beiersdorfer, P.; Magee, E. W.; Brown, G. V. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

    2016-11-15

    We report the calibration of the Orion High-Resolution X-ray (OHREX) imaging crystal spectrometer at the EBIT-I electron beam ion trap at Livermore. Two such instruments, dubbed OHREX-1 and OHREX-2, are fielded for plasma diagnostics at the Orion laser facility in the United Kingdom. The OHREX spectrometer can simultaneously house two spherically bent crystals with a radius of curvature of r = 67.2 cm. The focusing properties of the spectrometer allow both for larger distance to the source due to the increase in collected light and for observation of extended sources. OHREX is designed to cover a 2.5°–3° spectral range at Bragg angles around 51.3°. The typically high resolving powers at these large Bragg angles are ideally suited for line shape diagnostics. For instance, the nominal resolving power of the instrument (>10 000) is much higher than the effective resolving power associated with the Doppler broadening due to the temperature of the trapped ions in EBIT-I. The effective resolving power is only around 3000 at typical EBIT-I conditions, which nevertheless is sufficient to set up and test the instrument’s spectral characteristics. We have calibrated the spectral range for a number of crystals using well known reference lines in the first and second order and derived the ion temperatures from these lines. We have also made use of the 50 μm size of the EBIT-I source width to characterize the spatial focusing of the spectrometer.

  11. Precision Beam Parameter Monitoring in a Measurement of the Weak Mixing Angle in Moeller Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Cooke, M.S.

    2005-04-11

    A precision measurement of the parity nonconserving left-right asymmetry, A{sub LR}, in Moeller scattering (e{sup -}e{sup -} {yields} e{sup -}e{sup -}) is currently in progress at the Stanford Linear Accelerator Center (SLAC). This experiment, labeled SLAC-E158, scatters longitudinally polarized electrons off atomic electrons in an unpolarized hydrogen target at a Q{sup 2} of 0.03 (GeV/c){sup 2}. The asymmetry, which is the fractional difference in the scattering cross-sections, measures the effective pseudo-scalar weak neutral current coupling, g{sub ee}, governing Moeller scattering. This quantity is in turn proportional to (1/4 - sin{sup 2} {theta}{sub w}), where {theta}{sub w} is the electroweak mixing angle. The goal is to measure the asymmetry to a precision of 1 x 10{sup -8} which corresponds to {delta}(sin{sup 2} {theta}{sub w}) {approx} 0.0007. Since A{sub LR} is a function of the cross-sections, and the cross-sections depend on the beam parameters, the desired precision of A{sub LR} places stringent requirements on the beam parameters. This paper investigates the requirements on the beam parameters and discusses the means by which they are monitored and accounted for.

  12. Scatter measurement and correction method for cone-beam CT based on single grating scan

    Science.gov (United States)

    Huang, Kuidong; Shi, Wenlong; Wang, Xinyu; Dong, Yin; Chang, Taoqi; Zhang, Hua; Zhang, Dinghua

    2017-06-01

    In cone-beam computed tomography (CBCT) systems based on flat-panel detector imaging, the presence of scatter significantly reduces the quality of slices. Based on the concept of collimation, this paper presents a scatter measurement and correction method based on single grating scan. First, according to the characteristics of CBCT imaging, the scan method using single grating and the design requirements of the grating are analyzed and figured out. Second, by analyzing the composition of object projection images and object-and-grating projection images, the processing method for the scatter image at single projection angle is proposed. In addition, to avoid additional scan, this paper proposes an angle interpolation method of scatter images to reduce scan cost. Finally, the experimental results show that the scatter images obtained by this method are accurate and reliable, and the effect of scatter correction is obvious. When the additional object-and-grating projection images are collected and interpolated at intervals of 30 deg, the scatter correction error of slices can still be controlled within 3%.

  13. Optimizing a neutron-beam focusing device for the direct geometry time-of-flight spectrometer TOFTOF at the FRM II reactor source

    DEFF Research Database (Denmark)

    Rasmussen, N. G.; Simeoni, G. G.; Lefmann, K.

    2016-01-01

    A dedicated beam-focusing device has been designed for the direct geometry thermal-cold neutron time-of-flight spectrometer TOFTOF at the neutron facility FRM II (Garching, Germany). The prototype, based on the compressed Archimedes' mirror concept, benefits from the adaptive-optics technology (a...... than 3.5 would have only marginal influence on the optimal behaviour, whereas comparable spectrometers could take advantage of longer focusing segments, with particular impact for the thermal region of the neutron spectrum....

  14. Acoustic scattering of a Bessel vortex beam by a rigid fixed spheroid

    Science.gov (United States)

    Mitri, F. G.

    2015-12-01

    Partial-wave series representation of the acoustic scattering field of high-order Bessel vortex beams by rigid oblate and prolate spheroids using the modal matching method is developed. The method, which is applicable to slightly elongated objects at low-to-moderate frequencies, requires solving a system of linear equations which depends on the partial-wave index n and the order of the Bessel vortex beam m using truncated partial-wave series expansions (PWSEs), and satisfying the Neumann boundary condition for a rigid immovable surface in the least-squares sense. This original semi-analytical approach developed for Bessel vortex beams is demonstrated for finite oblate and prolate spheroids, where the mathematical functions describing the spheroidal geometry are written in a form involving single angular (polar) integrals that are numerically computed. The transverse (θ = π / 2) and 3D scattering directivity patterns are evaluated in the far-field for both prolate and oblate spheroids, with particular emphasis on the aspect ratio (i.e., the ratio of the major axis over the minor axis of the spheroid) not exceeding 3:1, the half-cone angle β and order m of the Bessel vortex beam, as well as the dimensionless size parameter kr0. Periodic oscillations in the magnitude plots of the far-field scattering form function are observed, which result from the interference of the reflected waves with the circumferential (Franz') waves circumnavigating the surface of the spheroid in the surrounding fluid. Moreover, the 3D directivity patterns illustrate the far-field scattering from the spheroid, that vanishes in the forward (θ = 0) and backward (θ = π) directions. Particular applications in underwater acoustics and scattering, acoustic levitation and the detection of submerged elongated objects using Bessel vortex waves to name a few, would benefit from the results of the present investigation.

  15. Multiple Coulomb scattering of high-energy heavy charged particle beams used in biology and medicine

    International Nuclear Information System (INIS)

    Wong, M.; Schimmerling, W.; Ludewigt, B.; Phillips, M.; Curtis, S.; Tobias, C.A.

    1987-01-01

    The authors measured lateral displacement and angular distributions of high-energy heavy charged particles emerging from a target at the Lawrence Berkeley Laboratory BEVALAC with beams used in radiobiology experiments. Multiple Coulomb scattering occurring in the target material generally spreads the beam laterally and increases its divergence. The apparatus consists of four sets of position-sensitive semiconductor detectors located along the beam line. Each providing two position signals and one energy signal. The difference between the two position signals is used to determine the particle position in one dimension. The two position signals are constrained to add up to the energy deposition signal in order to reject multiple-particle traversals. The vector directions for the incident and emerging particles are reconstructed in three dimensions from their measured coordinated positions. Lateral and angular distributions are reported for beams of high-energy neon, iron and uranium ions incident on targets of aluminum, cooper, lead and water

  16. Studies of isotopic defined hydrogen beams scattering from Pd single-crystal surfaces

    International Nuclear Information System (INIS)

    Varlam, Mihai; Steflea, Dumitru

    2001-01-01

    An experimental investigation of hydrogen isotopes interaction with Pd single-crystal surface has been carried out using molecular beam technique. The energy dependence of the sticking probability and its relation with the trapping probability into the precursor state is studied by integrating the scattered angular distribution of hydrogen Isotopic defined beams from Pd (111) surface in the 40-400 K surface temperature range. The dependence has been evaluated by defining hydrogen molecular beams with different isotopic concentration - from the natural one to the 5% D/(D+H) ratio - and for different incident energies. The beam was directed onto a single-crystal Pd (111) surface. In the paper, we report the experimental results and some considerations related to it. (authors)

  17. Coherent Forward Stimulated-Brillouin Scattering of a Spatially Incoherent Laser Beam in a Plasma and Its Effect on Beam Spray

    International Nuclear Information System (INIS)

    Grech, M.; Riazuelo, G.; Pesme, D.; Weber, S.; Tikhonchuk, V. T.

    2009-01-01

    A statistical model for forward stimulated-Brillouin scattering is developed for a spatially incoherent, monochromatic, laser beam propagating in a plasma. The threshold above which the laser beam spatial incoherence cannot prevent the coherent growth of forward stimulated-Brillouin scattering is computed. It is found to be well below the threshold for self-focusing. Three-dimensional simulations confirm its existence and reveal the onset of beam spray above it. From these results, we propose a new figure of merit for the control of propagation through a plasma of a spatially incoherent laser beam

  18. Molecular beam mass spectrometer equipped with a catalytic wall reactor for in situ studies in high temperature catalysis research

    International Nuclear Information System (INIS)

    Horn, R.; Ihmann, K.; Ihmann, J.; Jentoft, F.C.; Geske, M.; Taha, A.; Pelzer, K.; Schloegl, R.

    2006-01-01

    A newly developed apparatus combining a molecular beam mass spectrometer and a catalytic wall reactor is described. The setup has been developed for in situ studies of high temperature catalytic reactions (>1000 deg. C), which involve besides surface reactions also gas phase reactions in their mechanism. The goal is to identify gas phase radicals by threshold ionization. A tubular reactor, made from the catalytic material, is positioned in a vacuum chamber. Expansion of the gas through a 100 μm sampling orifice in the reactor wall into differentially pumped nozzle, skimmer, and collimator chambers leads to the formation of a molecular beam. A quadrupole mass spectrometer with electron impact ion source designed for molecular beam inlet and threshold ionization measurements is used as the analyzer. The sampling time from nozzle to detector is estimated to be less than 10 ms. A detection time resolution of up to 20 ms can be reached. The temperature of the reactor is measured by pyrometry. Besides a detailed description of the setup components and the physical background of the method, this article presents measurements showing the performance of the apparatus. After deriving the shape and width of the energy spread of the ionizing electrons from measurements on N 2 and He we estimated the detection limit in threshold ionization measurements using binary mixtures of CO in N 2 to be in the range of several hundreds of ppm. Mass spectra and threshold ionization measurements recorded during catalytic partial oxidation of methane at 1250 deg. C on a Pt catalyst are presented. The detection of CH 3 · radicals is successfully demonstrated

  19. Molecular beam mass spectrometer equipped with a catalytic wall reactor for in situ studies in high temperature catalysis research

    Science.gov (United States)

    Horn, R.; Ihmann, K.; Ihmann, J.; Jentoft, F. C.; Geske, M.; Taha, A.; Pelzer, K.; Schlögl, R.

    2006-05-01

    A newly developed apparatus combining a molecular beam mass spectrometer and a catalytic wall reactor is described. The setup has been developed for in situ studies of high temperature catalytic reactions (>1000°C), which involve besides surface reactions also gas phase reactions in their mechanism. The goal is to identify gas phase radicals by threshold ionization. A tubular reactor, made from the catalytic material, is positioned in a vacuum chamber. Expansion of the gas through a 100μm sampling orifice in the reactor wall into differentially pumped nozzle, skimmer, and collimator chambers leads to the formation of a molecular beam. A quadrupole mass spectrometer with electron impact ion source designed for molecular beam inlet and threshold ionization measurements is used as the analyzer. The sampling time from nozzle to detector is estimated to be less than 10ms. A detection time resolution of up to 20ms can be reached. The temperature of the reactor is measured by pyrometry. Besides a detailed description of the setup components and the physical background of the method, this article presents measurements showing the performance of the apparatus. After deriving the shape and width of the energy spread of the ionizing electrons from measurements on N2 and He we estimated the detection limit in threshold ionization measurements using binary mixtures of CO in N2 to be in the range of several hundreds of ppm. Mass spectra and threshold ionization measurements recorded during catalytic partial oxidation of methane at 1250°C on a Pt catalyst are presented. The detection of CH3• radicals is successfully demonstrated.

  20. Deep inelastic neutron scattering on {sup 207}Pb and NaHF{sub 2} as a test of a detectors array on the VESUVIO spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Pietropaolo, A. [Universita degli Studi di Roma Tor Vergata, Dipartimento di Fisica and Centro NAST - Nanoscienze and Nanotecnologie and Strumentazione, via della Ricerca Scientifica 1, 00133 Rome (Italy)], E-mail: antonino.pietropaolo@roma2.infn.it; Senesi, R. [Universita degli Studi di Roma Tor Vergata, Dipartimento di Fisica and Centro NAST - Nanoscienze and Nanotecnologie and Strumentazione, via della Ricerca Scientifica 1, 00133 Rome (Italy)

    2008-01-11

    A prototype array of resonance detectors for deep inelastic neutron scattering experiments has been installed on the VESUVIO spectrometer, at the ISIS spallation neutron source. Deep inelastic neutron scattering measurements on a reference lead sample and on NaHF{sub 2} molecular system are presented. Despite on an explorative level, the results obtained for the values of mean kinetic energy are found in good agreement with the theoretical predictions, thus assessing the potential capability of the device for a routine use on the instrument.

  1. Deep inelastic neutron scattering on 207Pb and NaHF 2 as a test of a detectors array on the VESUVIO spectrometer

    Science.gov (United States)

    Pietropaolo, A.; Senesi, R.

    2008-01-01

    A prototype array of resonance detectors for deep inelastic neutron scattering experiments has been installed on the VESUVIO spectrometer, at the ISIS spallation neutron source. Deep inelastic neutron scattering measurements on a reference lead sample and on NaHF 2 molecular system are presented. Despite on an explorative level, the results obtained for the values of mean kinetic energy are found in good agreement with the theoretical predictions, thus assessing the potential capability of the device for a routine use on the instrument.

  2. Deep inelastic neutron scattering on 207Pb and NaHF2 as a test of a detectors array on the VESUVIO spectrometer

    International Nuclear Information System (INIS)

    Pietropaolo, A.; Senesi, R.

    2008-01-01

    A prototype array of resonance detectors for deep inelastic neutron scattering experiments has been installed on the VESUVIO spectrometer, at the ISIS spallation neutron source. Deep inelastic neutron scattering measurements on a reference lead sample and on NaHF 2 molecular system are presented. Despite on an explorative level, the results obtained for the values of mean kinetic energy k > are found in good agreement with the theoretical predictions, thus assessing the potential capability of the device for a routine use on the instrument

  3. Development of Neutron Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chang Hee; Lee, J. S.; Seong, B. S. (and others)

    2007-06-15

    Neutron spectrometers which are used in the basic researches such as physics, chemistry and materials science and applied in the industry were developed at the horizontal beam port of HANARO reactor. In addition, the development of core components for neutron scattering and the upgrade of existing facilities are also performed. The vertical neutron reflectometer was fabricated and installed at ST3 beam port. The performance test of the reflectometer was completed and the reflectometer was opened to users. The several core parts and options were added in the polarized neutron spectrometer. The horizontal neutron reflectometer from Brookhaven National Laboratory was moved to HANARO and installed, and the performance of the reflectometer was examined. The HIPD was developed and the performance test was completed. The base shielding for TAS was fabricated. The soller collimator, Cu mosaic monochromator, Si BPC monochromator and position sensitive detector were developed and applied in the neutron spectrometer as part of core component development activities. In addition, the sputtering machine for mirror device are fabricated and the neutron mirror is made using the sputtering machine. The FCD was upgraded and the performance of the FCD are improved over the factor of 10. The integration and upgrade of the neutron detection system were also performed.

  4. Measurements of refractive index and size of a spherical drop from Gaussian beam scattering in the primary rainbow region

    Science.gov (United States)

    Yu, Haitao; Sun, Hui; Shen, Jianqi; Tropea, Cameron

    2018-03-01

    The primary rainbow observed when light is scattered by a spherical drop has been exploited in the past to measure drop size and relative refractive index. However, if higher spatial resolution is required in denser drop ensembles/sprays, and to avoid then multiple drops simultaneously appearing in the measurement volume, a highly focused beam is desirable, inevitably with a Gaussian intensity profile. The present study examines the primary rainbow pattern resulting when a Gaussian beam is scattered by a spherical drop and estimates the attainable accuracy when extracting size and refractive index. The scattering is computed using generalized Lorenz-Mie theory (GLMT) and Debye series decomposition of the Gaussian beam scattering. The results of these simulations show that the measurement accuracy is dependent on both the beam waist radius and the position of the drop in the beam waist.

  5. Study of a filter spectrometer in the framework of a new method for measuring the temperature of thermonuclear plasmas by relativistic Thomson scattering

    International Nuclear Information System (INIS)

    Lasalle, J.

    1975-06-01

    A new method which greatly simplifies the number of measurements necessary for obtaining the temperature in thermonuclear plasmas, using the relativistic effects of Thomson scattering is presented. A few orders of magnitude are computed for probing the feasibility of such temperature measurements. The data used correspond to magnitudes relating to T.F.R. The characteristics of a filter equipped spectrometer are then defined in view of a double function: separation of the lambda>lambda laser and lambda [fr

  6. Distributed Strain Measurement along a Concrete Beam via Stimulated Brillouin Scattering in Optical Fibers

    Directory of Open Access Journals (Sweden)

    Romeo Bernini

    2011-01-01

    Full Text Available The structural strain measurement of tension and compression in a 4 m long concrete beam was demonstrated with a distributed fiber-optic sensor portable system based on Brillouin scattering. Strain measurements provided by the fiber-optic sensor permitted to detect the formation of a crack in the beam resulting from the external applied load. The sensor system is valuable for structural monitoring applications, enabling the long-term performance and health of structures to be efficiently monitored.

  7. Development of a Supersonic Atomic Oxygen Nozzle Beam Source for Crossed Beam Scattering Experiments

    Science.gov (United States)

    Sibener, S. J.; Buss, R. J.; Lee, Y. T.

    1978-05-01

    A high pressure, supersonic, radio frequency discharge nozzle beam source was developed for the production of intense beams of ground state oxygen atoms. An efficient impedance matching scheme was devised for coupling the radio frequency power to the plasma as a function of both gas pressure and composition. Techniques for localizing the discharge directly behind the orifice of a water-cooled quartz nozzle were also developed. The above combine to yield an atomic oxygen beam source which produces high molecular dissociation in oxygen seeded rare gas mixtures at total pressures up to 200 torr: 80 to 90% dissociation for oxygen/argon mixtures and 60 to 70% for oxygen/helium mixtures. Atomic oxygen intensities are found to be greater than 10{sup 17} atom sr{sup -1} sec{sup -1}. A brief discussion of the reaction dynamics of 0 + IC1 ..-->.. I0 + C1 is also presented.

  8. Large Logarithms in the Beam Normal Spin Asymmetry of Elastic Electron--Proton Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Andrei Afanasev; Mykola Merenkov

    2004-06-01

    We study a parity-conserving single-spin beam asymmetry of elastic electron-proton scattering induced by an absorptive part of the two-photon exchange amplitude. It is demonstrated that excitation of inelastic hadronic intermediate states by the consecutive exchange of two photons leads to logarithmic and double-logarithmic enhancement due to contributions of hard collinear quasi-real photons. The asymmetry at small electron scattering angles is expressed in terms of the total photoproduction cross section on the proton, and is predicted to reach the magnitude of 20-30 parts per million. At these conditions and fixed 4-momentum transfers, the asymmetry is rising logarithmically with increasing electron beam energy, following the high-energy diffractive behavior of total photoproduction cross section on the proton.

  9. Measurement of the primary and scatter dose in high energy photon beams

    Energy Technology Data Exchange (ETDEWEB)

    Van der Linden, P M [Catharina Ziekenhuis, Eindhoven (Netherlands). Radiotherapy Dept.; Tiourina, T B; Dries, W

    1995-12-01

    A method is presented to measure the primary and scatter components separately in a water tank using a small cylindrical absorber. Results from this experiment are compared with Monte Carlo calculations. The measurement setup consists of a small cylindrical absorber placed on a central axis of the beam a few centimetres above the radiation detector. Both absorber and detector move along the central axis while absorbed dose is registered. As the primary radiation is fully blocked, only scatter component is measured when a cylindrical absorber is used. Measurements in open fields result in the total absorbed dose being the sum of primary and scatter components. The primary dose component can be derived by substraction. Absorbers with different diameters are used. With decreasing dimensions the relative contribution of the dose due to scatter radiation increases. A steep increase is observed when the range of laterally scattered electrons becomes comparable with the radius of the absorber. Two different Monte Carlo simulations have been performed: with and without secondary electron transport. The data obtained for the former case perfectly agrees with the experiment. The situation where the secondary electron is assumed zero (i.e. local energy deposition) simulates the Cunningham model. Our results show that the Cunningham model predicts lower scatter component under the block edge which can be important for these applications.

  10. Neutron scattering in Indonesia. Country report

    Energy Technology Data Exchange (ETDEWEB)

    Ikram, Abarrul [Neutron Scattering Laboratory, R and D Center for Materials Science and Technology, National Nuclear Energy Agency, Serpong (Indonesia)

    2000-10-01

    Neutron scattering in Indonesia is still alienated due to some reasons and conditions which are discussed. The reactor and its latest operation mode are also described. The neutron beam facilities which include one diffractometer for residual stress measurement, one diffractometer for single crystal structural determination and texture measurement, one high resolution powder diffractometer, one neutron radiography facility, one triple axis spectrometer, one small angle neutron scattering spectrometer and one high resolution small angle neutron scattering spectrometer were presented briefly together with improvements of neutron intensities at some spectrometers in connection with the setting of main beam shutter position. Special attention is given for four instruments mostly related to this workshop. Their performances and problems faced in the past 9 months are presented as well as the future plan for refurbishment and development. (author)

  11. Axisymmetric scattering of an acoustical Bessel beam by a rigid fixed spheroid.

    Science.gov (United States)

    Mitri, Farid G

    2015-10-01

    Based on the partial-wave series expansion (PWSE) method in spherical coordinates, a formal analytical solution for the acoustic scattering of a zeroth-order Bessel acoustic beam centered on a rigid fixed (oblate or prolate) spheroid is provided. The unknown scattering coefficients of the spheroid are determined by solving a system of linear equations derived for the Neumann boundary condition. Numerical results for the modulus of the backscattered pressure (θ = π) in the near field and the backscattering form function in the far field for both prolate and oblate spheroids are presented and discussed, with particular emphasis on the aspect ratio (i.e., the ratio of the major axis over the minor axis of the spheroid), the half-cone angle of the Bessel beam, and the dimensionless frequency. The plots display periodic oscillations (versus the dimensionless frequency) because of the interference of specularly reflected waves in the backscattering direction with circumferential Franz' waves circumnavigating the surface of the spheroid in the surrounding fluid. Moreover, the 3-D directivity patterns illustrate the near- and far-field axisymmetric scattering. Investigations in underwater acoustics, particle levitation, scattering, and the detection of submerged elongated objects and other related applications utilizing Bessel waves would benefit from the results of the present study.

  12. INFLUENCE OF LASER BEAM PROFILE ON LIGHT SCATTERING BY HUMAN SKIN DURING PHOTOMETRY BY ELLIPSOIDAL REFLECTORS

    Directory of Open Access Journals (Sweden)

    M. A. Bezuglyi

    2018-01-01

    Full Text Available The correct accounting of laser emitter parameters for improvement of diagnostic authenticity of methods of optical biomedical diagnostic is important problem for applied biophotonic tasks. The purpose of the current research is estimation of influence of energy distribution profile in transversal section of laser beam on light scattering by human skin layers at photometry by ellipsoidal reflectors.Biomedical photometer with ellipsoidal reflectors for investigation of biological tissue specimens in transmitted and reflected light uses laser probing radiation with infinitely thin, Gauss-type and uniform cross-section profile. Distribution of beams with denoted profiles, which consist of 20 million photons with wavelength 632.8 nm, was modeled by using of Monte-Carlo simulation in human skin layers (corneous layer, epidermis, derma and adipose tissue of various anatomic thickness and with ellipsoidal reflectors with focal parameter equal to 16.875 mm and eccentricity of 0.66.The modeling results represent that illuminance distribution in zones of photometric imaging is significantly influenced by the laser beam cross-section profile for various thickness of corneous layer and epidermis in transmitted and reflected light, and also derma in reflected light. Illuminance distribution for adipose tissue in reflected and transmitted light, and also derma in transmitted light, practically do not depend of laser beam profile for anatomic thicknesses, which are appropriate for human skin on various sections of body.There are represented results of modified Monte-Carlo simulation method for biomedical photometer with ellipsoidal reflectors during biometry of human skin layers. For highly scattered corneous layer and epidermis the illumination of middle and external rings of photometric images changes depending from the laser beam profile for more than 50 % in transmitted and 30 % in reflected light. For weakly scattering skin layers (derma and adipose layer

  13. Characterization of Scattered X-Ray Photons in Dental Cone-Beam Computed Tomography.

    Science.gov (United States)

    Yang, Ching-Ching

    2016-01-01

    Scatter is a very important artifact causing factor in dental cone-beam CT (CBCT), which has a major influence on the detectability of details within images. This work aimed to improve the image quality of dental CBCT through scatter correction. Scatter was estimated in the projection domain from the low frequency component of the difference between the raw CBCT projection and the projection obtained by extrapolating the model fitted to the raw projections acquired with 2 different sizes of axial field-of-view (FOV). The function for curve fitting was optimized by using Monte Carlo simulation. To validate the proposed method, an anthropomorphic phantom and a water-filled cylindrical phantom with rod inserts simulating different tissue materials were scanned using 120 kVp, 5 mA and 9-second scanning time covering an axial FOV of 4 cm and 13 cm. The detectability of the CT image was evaluated by calculating the contrast-to-noise ratio (CNR). Beam hardening and cupping artifacts were observed in CBCT images without scatter correction, especially in those acquired with 13 cm FOV. These artifacts were reduced in CBCT images corrected by the proposed method, demonstrating its efficacy on scatter correction. After scatter correction, the image quality of CBCT was improved in terms of target detectability which was quantified as the CNR for rod inserts in the cylindrical phantom. Hopefully the calculations performed in this work can provide a route to reach a high level of diagnostic image quality for CBCT imaging used in oral and maxillofacial structures whilst ensuring patient dose as low as reasonably achievable, which may ultimately make CBCT scan a reliable and safe tool in clinical practice.

  14. Characterization of Scattered X-Ray Photons in Dental Cone-Beam Computed Tomography.

    Directory of Open Access Journals (Sweden)

    Ching-Ching Yang

    Full Text Available Scatter is a very important artifact causing factor in dental cone-beam CT (CBCT, which has a major influence on the detectability of details within images. This work aimed to improve the image quality of dental CBCT through scatter correction.Scatter was estimated in the projection domain from the low frequency component of the difference between the raw CBCT projection and the projection obtained by extrapolating the model fitted to the raw projections acquired with 2 different sizes of axial field-of-view (FOV. The function for curve fitting was optimized by using Monte Carlo simulation. To validate the proposed method, an anthropomorphic phantom and a water-filled cylindrical phantom with rod inserts simulating different tissue materials were scanned using 120 kVp, 5 mA and 9-second scanning time covering an axial FOV of 4 cm and 13 cm. The detectability of the CT image was evaluated by calculating the contrast-to-noise ratio (CNR.Beam hardening and cupping artifacts were observed in CBCT images without scatter correction, especially in those acquired with 13 cm FOV. These artifacts were reduced in CBCT images corrected by the proposed method, demonstrating its efficacy on scatter correction. After scatter correction, the image quality of CBCT was improved in terms of target detectability which was quantified as the CNR for rod inserts in the cylindrical phantom.Hopefully the calculations performed in this work can provide a route to reach a high level of diagnostic image quality for CBCT imaging used in oral and maxillofacial structures whilst ensuring patient dose as low as reasonably achievable, which may ultimately make CBCT scan a reliable and safe tool in clinical practice.

  15. Resonance proton scattering use for the beam parameters control of the electrostatic accelerator

    Directory of Open Access Journals (Sweden)

    V. I. Soroka

    2013-12-01

    Full Text Available The paper discusses peculiarities of the resonance proton scattering use for the beam parameters control of the electrostatic accelerators. The expediency of the use has been confirmed by experiment. Peculiarities are caused because elastic resonance scattering through the stage of compound nucleus is always accompanied by potential and Coulomb scattering. These three components interfere and for that reason the resonance form de-pends on a scattering angle and total angular moment of a compound nucleus level. However, possessing neces-sary information in the given field of nuclear spectroscopy enables the selection of resonance with the character-istics suitable for the calibration purpose. Considerable increase of the scattering cross section in the resonance region saves the time and simplifies the experiment technical maintenance. The experiments were performed at the 10 MeV tandem accelerator of the Institute for Nuclear Research, National Academy of Sciences of Ukraine, Kyiv, after its modernization. Silicon and oxygen were used as the targets. Silicon targets were of two types of thickness: 1 the target of complete absorption, 2 the target with the thickness in which the loss of protons ener-gy exceeded the width of the selected resonance. The elastic and non elastic scattering from silicon were used in region of the 3,100 MeV proton energy resonance. Oxygen target, as component of the surface oxidizing layer on beryllium had the thickness which in terms of the loss of proton energy was less than the width of the selected elastic narrow resonance at 3,470 MeV proton energy. As result of the measurement the corrections concerning the energy scale of the accelerator and protons energy spread in the beam were proposed.

  16. Nonlinear propagation of a spatially incoherent laser beam: self-induced smoothing and reduction of scattering instabilities

    International Nuclear Information System (INIS)

    Maximov, A.V.; Ourdev, I.G.; Rozmus, W.; Capjack, C.E.; Mounaix, Ph.; Huller, S.; Pesme, D.; Tikhonchuk, V.T.; Divol, L.

    2000-01-01

    It is shown that plasma-induced angular spreading and spectral broadening of a spatially incoherent laser beam correspond to increased spatial and temporal incoherence of the laser light. The spatial incoherence is characterized by an effective beam f-number, decreasing in space along the direction of light propagation. Plasma-induced beam smoothing can influence laser-plasma interaction physics. In particular, decreasing the correlation time of the propagating laser light may dramatically reduce the levels of backward stimulated Brillouin and Raman scattering inside the plasma. Also, the decrease of the laser beam effective f-number reduces the reflectivity of backward stimulated Brillouin scattering. (authors)

  17. Proposal for characterization of muon spectrometers for neutrino beam lines with the Baby MIND

    CERN Document Server

    Noah, E

    2015-01-01

    Neutrino detectors based on state-of-the-art plastic scintillators read out with solid state photo-sensors, as well as new magnetization schemes, have been developed in the framework of AIDA. Meaningful size prototypes are under construction. In the framework of the CERN neutrino platform, we propose to test a Totally Active Scintillator Detector (TASD) and a prototype of a Magnetized Iron Neutrino Detector (MIND), called Baby MIND in the H8 beam line in 2016-2018. The design of the detectors and the purpose and plans for the beam tests are presented. An opportunity to use the Baby MIND detector in a real neutrino beam at JPARC for the measurement of the cross-section ratio between Water and scintillator (WAGASCI experiment) is described.

  18. Direct measurements of surface scattering in Si nanosheets using a microscale phonon spectrometer: implications for Casimir-limit predicted by Ziman theory.

    Science.gov (United States)

    Hertzberg, Jared B; Aksit, Mahmut; Otelaja, Obafemi O; Stewart, Derek A; Robinson, Richard D

    2014-02-12

    Thermal transport in nanostructures is strongly affected by phonon-surface interactions, which are expected to depend on the phonon's wavelength and the surface roughness. Here we fabricate silicon nanosheets, measure their surface roughness (∼ 1 nm) using atomic force microscopy (AFM), and assess the phonon scattering rate in the sheets with a novel technique: a microscale phonon spectrometer. The spectrometer employs superconducting tunnel junctions (STJs) to produce and detect controllable nonthermal distributions of phonons from ∼ 90 to ∼ 870 GHz. This technique offers spectral resolution nearly 10 times better than a thermal conductance measurement. We compare measured phonon transmission rates to rates predicted by a Monte Carlo model of phonon trajectories, assuming that these trajectories are dominated by phonon-surface interactions and using the Ziman theory to predict phonon-surface scattering rates based on surface topology. Whereas theory predicts a diffuse surface scattering probability of less than 40%, our measurements are consistent with a 100% probability. Our nanosheets therefore exhibit the so-called "Casimir limit" at a much lower frequency than expected if the phonon scattering rates follow the Ziman theory for a 1 nm surface roughness. Such a result holds implications for thermal management in nanoscale electronics and the design of nanostructured thermoelectrics.

  19. Evaluation of the spectral distribution of X-ray beams from measurements on the scattered radiation

    International Nuclear Information System (INIS)

    Casnati, E.; Baraldi, C.

    1980-01-01

    Most of the phenomena activated by photons with energies below 100 keV show an apparent or real dependence on the quantum energy. Therefore, knowledge of the beam energy characteristics is of primary importance for interpretation of the irradiation results. The greatest difficulty arises from the high flux density of the beams usually employed which does not allow direct measurements of the beam. A method was developed which permits evaluation of the spectral distribution of the X-ray beam from a spectrometric measurement of the radiation scattered by a thin foil of a suitable metal. This makes possible a new and more rational approach to the measurement of X-rays in the energy range where the interaction parameters show a large photon energy dependence. The corrections required by the presence of some collateral effects, among which the most important is the coexistence of the coherent and incoherent scattering, must be evaluated. The knowledge of the spectral distribution is of immediate usefulness for studies of radiation damage in biological and other materials, for the calibration of radiation measuring instruments and for the improvement of the radiological instrumentation response which contributes to reducing the patient's dose. (H.K.)

  20. A scatter model for fast neutron beams using convolution of diffusion kernels

    International Nuclear Information System (INIS)

    Moyers, M.F.; Horton, J.L.; Boyer, A.L.

    1988-01-01

    A new model is proposed to calculate dose distributions in materials irradiated with fast neutron beams. Scattered neutrons are transported away from the point of production within the irradiated material in the forward, lateral and backward directions, while recoil protons are transported in the forward and lateral directions. The calculation of dose distributions, such as for radiotherapy planning, is accomplished by convolving a primary attenuation distribution with a diffusion kernel. The primary attenuation distribution may be quickly calculated for any given set of beam and material conditions as it describes only the magnitude and distribution of first interaction sites. The calculation of energy diffusion kernels is very time consuming but must be calculated only once for a given energy. Energy diffusion distributions shown in this paper have been calculated using a Monte Carlo type of program. To decrease beam calculation time, convolutions are performed using a Fast Fourier Transform technique. (author)

  1. Studies of isotopic defined hydrogen beams scattering from Pd single-crystal surfaces

    International Nuclear Information System (INIS)

    Varlam, Mihai; Steflea, Dumitru

    1999-01-01

    An experimental investigation of hydrogen isotopes interaction with Pd single-crystal surfaces has been carried out using molecular beam technique. The energy dependence of the sticking probability and its relation with the trapping probability into the precursor state is studied by integrating the scattered angular distribution of hydrogen isotopic defined beams from Pd (111) surfaces in the 40 - 400 K surface temperature range. The dependence has been evaluated by defining hydrogen molecular beams with different isotopic concentration - from the natural one until 5% D/(D + H) and different incident energies and directed onto a single - crystal Pd (111) surface. In the paper, we report the experimental results and some considerations related to them. (authors)

  2. A silicon microstrip detector in a magnetic spectrometer for high-resolution electron scattering experiments at the S-DALINAC

    International Nuclear Information System (INIS)

    Lenhardt, A.W.; Bonnes, U.; Burda, O.; Neumann-Cosel, P. von; Platz, M.; Richter, A.; Watzlawik, S.

    2006-01-01

    A silicon microstrip detector was developed as focal plane detector of the 169.7 deg. magic angle double-focussing spectrometer at the superconducting Darmstadt electron linear accelerator (S-DALINAC). It allows experiments with minimum ionizing electrons at data rates up to 100 kHz, utilizing the maximum resolution of the spectrometer achievable in dispersion-matching mode

  3. Resonant Raman scattering in ion-beam-synthesized Mg2Si in a silicon matrix

    International Nuclear Information System (INIS)

    Baleva, M.; Zlateva, G.; Atanassov, A.; Abrashev, M.; Goranova, E.

    2005-01-01

    Resonant Raman scattering by ion beam synthesized in silicon matrix Mg 2 Si phase is studied. The samples are prepared with the implantation of 24 Mg + ions with dose 4x10 17 cm -2 and with two different energies 40 and 60 keV into (100)Si substrates. The far infrared spectra are used as criteria for the formation of the Mg 2 Si phase. The Raman spectra are excited with different lines of Ar + laser, with energies of the lines lying in the interval from 2.40 to 2.75 eV. The resonant scattering can be investigated using these laser lines, as far as according to the Mg 2 Si band structure, there are direct gaps with energies in the same region. The energy dependences of the scattered intensities in the case of the scattering by the allowed F 2g and the forbidden LO-type modes are experimentally obtained and theoretically interpreted. On the base of the investigation energies of the interband transitions in the Mg 2 Si are determined. It is found also that the resonant Raman scattering appears to be a powerful tool for characterization of a material with inclusions in it. In the particular case it is concluded that the Mg 2 Si phase is present in the form of a surface layer in the sample, prepared with implantation energy 40 keV and as low-dimensional precipitates, embedded in the silicon matrix, in the sample, prepared with the higher implantation energy

  4. A high-resolution time-of-flight spectrometer for fission fragments and ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Kosev, Krasimir Milchev

    2007-07-01

    For the purpose of fission-fragment detection a double time-of-flight (TOF) spectrometer has been developed. The key component of the TOF spectrometer is a TOF detector consisting of multichannel-plate (MCP) detectors with a position-sensitive readout, a foil for secondary electron (SE) production and an electrostatic mirror. The fission fragments are detected by measuring the SEs impinging on the position-sensitive anode after emission from the foil, acceleration and deflection by the electrostatic mirror. The functionality of the different detector components is proven in detail. Optimised schemes for the high-voltage supplies of the MCP detectors have been implemented successfully. In order to process the multichannel-plate detector signals optimally, a new state-of-the-art constant-fraction discriminator based on the amplitude and rise time compensated technique with very low threshold capabilities and optimised walk properties has been developed and incorporated into the setup. In a setup consisting of two mirror MCP detectors, we could successfully observe the TOF spectrum of a mixed ({sup 226}Ra,{sup 222}Rn,{sup 210}Po,{sup 218}Po,{sup 214}Po) {alpha}-source. Testing photo-fission experiments were performed at the bremsstrahlung facility at the ELBE accelerator. The setup consisted of two mirror detectors (first arm) and a 80 mm diameter MCP detector (second arm) with a {sup 238}U target positioned in between. TOF measurements with two bremsstrahlung end-point energies of 12.9 and 16.0 MeV were carried out. A clear cut separation of the TOF peaks for the medium-mass and heavy fission fragments was observed. (orig.)

  5. A high-resolution time-of-flight spectrometer for fission fragments and ion beams

    International Nuclear Information System (INIS)

    Kosev, Krasimir Milchev

    2007-01-01

    For the purpose of fission-fragment detection a double time-of-flight (TOF) spectrometer has been developed. The key component of the TOF spectrometer is a TOF detector consisting of multichannel-plate (MCP) detectors with a position-sensitive readout, a foil for secondary electron (SE) production and an electrostatic mirror. The fission fragments are detected by measuring the SEs impinging on the position-sensitive anode after emission from the foil, acceleration and deflection by the electrostatic mirror. The functionality of the different detector components is proven in detail. Optimised schemes for the high-voltage supplies of the MCP detectors have been implemented successfully. In order to process the multichannel-plate detector signals optimally, a new state-of-the-art constant-fraction discriminator based on the amplitude and rise time compensated technique with very low threshold capabilities and optimised walk properties has been developed and incorporated into the setup. In a setup consisting of two mirror MCP detectors, we could successfully observe the TOF spectrum of a mixed ( 226 Ra, 222 Rn, 210 Po, 218 Po, 214 Po) α-source. Testing photo-fission experiments were performed at the bremsstrahlung facility at the ELBE accelerator. The setup consisted of two mirror detectors (first arm) and a 80 mm diameter MCP detector (second arm) with a 238 U target positioned in between. TOF measurements with two bremsstrahlung end-point energies of 12.9 and 16.0 MeV were carried out. A clear cut separation of the TOF peaks for the medium-mass and heavy fission fragments was observed. (orig.)

  6. The transmission theory of electrostatic analyzer in six dimensional phase space and the concept design of a supersensitive mass spectrometer beam line for HI-13 tandem accelerator

    International Nuclear Information System (INIS)

    Guan Xialing; Cao Qingxi; Zhang Jie; Ye Jingping

    1986-01-01

    It follows from the motion equations of charged particle in curvilinear coordinates system that the transfer matrix of electrostatic analyzer was derived in six dimensional phase space. In accordance with these matrixes, the concept design of the supersensitive mass spectrometer beam line for HI-13 tandem accelerator was calculated

  7. Determination of electron beam parameters by means of laser-Compton scattering

    Directory of Open Access Journals (Sweden)

    K. Chouffani

    2006-05-01

    Full Text Available Laser-Compton scattering (LCS experiments were carried out at the Idaho Accelerator Center using the 5 ns (FWHM and 22 MeV electron beam. The electron beam was brought to an approximate head-on collision with a 29 MW, 7 ns (FWHM, 10 Hz Nd:YAG laser. Clear and narrow x-ray peaks resulting from the interaction of relativistic electrons with the Nd:YAG laser second harmonic line at 532 nm were observed. We have developed a relatively new method of using LCS as a nonintercepting electron beam monitor. Our method focused on the variation of the shape of the LCS spectrum rather than the LCS intensity as a function of the observation angle in order to extract the electron beam parameters at the interaction region. The electron beam parameters were determined by making simultaneous fits to spectra taken across the LCS x-ray cone. This scan method allowed us also to determine the variation of LCS x-ray peak energies and spectral widths as a function of the detector angles. Experimental data show that in addition to being viewed as a potential bright, tunable, and quasimonochromatic x-ray source, LCS can provide important information on the electron beam pulse length, direction, energy, angular and energy spread. Since the quality of LCS x-ray peaks, such as degree of monochromaticity, peak energy and flux, depends strongly on the electron beam parameters, LCS can therefore be viewed as an important nondestructive tool for electron beam diagnostics.

  8. First spatial separation of a heavy ion isomeric beam with a multiple-reflection time-of-flight mass spectrometer

    Science.gov (United States)

    Dickel, T.; Plaß, W. R.; Ayet San Andres, S.; Ebert, J.; Geissel, H.; Haettner, E.; Hornung, C.; Miskun, I.; Pietri, S.; Purushothaman, S.; Reiter, M. P.; Rink, A.-K.; Scheidenberger, C.; Weick, H.; Dendooven, P.; Diwisch, M.; Greiner, F.; Heiße, F.; Knöbel, R.; Lippert, W.; Moore, I. D.; Pohjalainen, I.; Prochazka, A.; Ranjan, M.; Takechi, M.; Winfield, J. S.; Xu, X.

    2015-05-01

    211Po ions in the ground and isomeric states were produced via 238U projectile fragmentation at 1000 MeV/u. The 211Po ions were spatially separated in flight from the primary beam and other reaction products by the fragment separator FRS. The ions were energy-bunched, slowed-down and thermalized in a gas-filled cryogenic stopping cell (CSC). They were then extracted from the CSC and injected into a high-resolution multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS). The excitation energy of the isomer and, for the first time, the isomeric-to-ground state ratio were determined from the measured mass spectrum. In the subsequent experimental step, the isomers were spatially separated from the ions in the ground state by an ion deflector and finally collected with a silicon detector for decay spectroscopy. This pioneering experimental result opens up unique perspectives for isomer-resolved studies. With this versatile experimental method new isomers with half-lives longer than a few milliseconds can be discovered and their decay properties can be measured with highest sensitivity and selectivity. These experiments can be extended to studies with isomeric beams in nuclear reactions.

  9. Library based x-ray scatter correction for dedicated cone beam breast CT

    International Nuclear Information System (INIS)

    Shi, Linxi; Zhu, Lei; Vedantham, Srinivasan; Karellas, Andrew

    2016-01-01

    Purpose: The image quality of dedicated cone beam breast CT (CBBCT) is limited by substantial scatter contamination, resulting in cupping artifacts and contrast-loss in reconstructed images. Such effects obscure the visibility of soft-tissue lesions and calcifications, which hinders breast cancer detection and diagnosis. In this work, we propose a library-based software approach to suppress scatter on CBBCT images with high efficiency, accuracy, and reliability. Methods: The authors precompute a scatter library on simplified breast models with different sizes using the GEANT4-based Monte Carlo (MC) toolkit. The breast is approximated as a semiellipsoid with homogeneous glandular/adipose tissue mixture. For scatter correction on real clinical data, the authors estimate the breast size from a first-pass breast CT reconstruction and then select the corresponding scatter distribution from the library. The selected scatter distribution from simplified breast models is spatially translated to match the projection data from the clinical scan and is subtracted from the measured projection for effective scatter correction. The method performance was evaluated using 15 sets of patient data, with a wide range of breast sizes representing about 95% of general population. Spatial nonuniformity (SNU) and contrast to signal deviation ratio (CDR) were used as metrics for evaluation. Results: Since the time-consuming MC simulation for library generation is precomputed, the authors’ method efficiently corrects for scatter with minimal processing time. Furthermore, the authors find that a scatter library on a simple breast model with only one input parameter, i.e., the breast diameter, sufficiently guarantees improvements in SNU and CDR. For the 15 clinical datasets, the authors’ method reduces the average SNU from 7.14% to 2.47% in coronal views and from 10.14% to 3.02% in sagittal views. On average, the CDR is improved by a factor of 1.49 in coronal views and 2.12 in sagittal

  10. Library based x-ray scatter correction for dedicated cone beam breast CT

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Linxi; Zhu, Lei, E-mail: leizhu@gatech.edu [Nuclear and Radiological Engineering and Medical Physics Programs, The George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Vedantham, Srinivasan; Karellas, Andrew [Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts 01655 (United States)

    2016-08-15

    Purpose: The image quality of dedicated cone beam breast CT (CBBCT) is limited by substantial scatter contamination, resulting in cupping artifacts and contrast-loss in reconstructed images. Such effects obscure the visibility of soft-tissue lesions and calcifications, which hinders breast cancer detection and diagnosis. In this work, we propose a library-based software approach to suppress scatter on CBBCT images with high efficiency, accuracy, and reliability. Methods: The authors precompute a scatter library on simplified breast models with different sizes using the GEANT4-based Monte Carlo (MC) toolkit. The breast is approximated as a semiellipsoid with homogeneous glandular/adipose tissue mixture. For scatter correction on real clinical data, the authors estimate the breast size from a first-pass breast CT reconstruction and then select the corresponding scatter distribution from the library. The selected scatter distribution from simplified breast models is spatially translated to match the projection data from the clinical scan and is subtracted from the measured projection for effective scatter correction. The method performance was evaluated using 15 sets of patient data, with a wide range of breast sizes representing about 95% of general population. Spatial nonuniformity (SNU) and contrast to signal deviation ratio (CDR) were used as metrics for evaluation. Results: Since the time-consuming MC simulation for library generation is precomputed, the authors’ method efficiently corrects for scatter with minimal processing time. Furthermore, the authors find that a scatter library on a simple breast model with only one input parameter, i.e., the breast diameter, sufficiently guarantees improvements in SNU and CDR. For the 15 clinical datasets, the authors’ method reduces the average SNU from 7.14% to 2.47% in coronal views and from 10.14% to 3.02% in sagittal views. On average, the CDR is improved by a factor of 1.49 in coronal views and 2.12 in sagittal

  11. Propagation and scattering of optical light beams in free space, in atmosphere and in biological media

    Science.gov (United States)

    Sahin, Serkan

    With their first production implemented around 1960's, lasers have afterwards proven to be excellent light sources in building the technology. Subsequently, it has been shown that the extraordinary properties of lasers are related to their coherence properties. Recent developments in optics make it possible to synthesize partially coherent light beams from fully coherent ones. In the last several decades it was seen that using partially coherent light sources may be advantageous, in the areas such as laser surface processing, fiber and free-space optical communications, and medical diagnostics. In this thesis, I study extensively the generation, the propagation in different media, and the scattering of partially coherent light beams with respect to their spectral polarization and coherence states. For instance, I analyze the evolution of recently introduced degree of cross-polarization of light fields in free space; then develop a novel partially coherent light source which acquires and keeps a flat intensity profile around the axis at any distance in the far field; and investigate the interaction of electromagnetic random light with the human eye lens. A part of the thesis treats the effect of atmospheric turbulence on random light beams. Due to random variations in the refractive index, atmospheric turbulence modulates all physical and statistical properties of propagating beams. I have explored the possibility of employing the polarimetric domain of the beam for scintillation reduction, which positively affects the performance of free-space communication systems. I also discuss novel techniques for the sensing of rough targets in the turbulent atmosphere by polarization and coherence properties of light. The other contribution to the thesis is the investigation of light scattering from deterministic or random collections of particles, within the validity of first Born approximation. In the case of a random collection, I introduce and model the new quantity

  12. Experimental validation of the DPM Monte Carlo code using minimally scattered electron beams in heterogeneous media

    International Nuclear Information System (INIS)

    Chetty, Indrin J.; Moran, Jean M.; Nurushev, Teamor S.; McShan, Daniel L.; Fraass, Benedick A.; Wilderman, Scott J.; Bielajew, Alex F.

    2002-01-01

    A comprehensive set of measurements and calculations has been conducted to investigate the accuracy of the Dose Planning Method (DPM) Monte Carlo code for electron beam dose calculations in heterogeneous media. Measurements were made using 10 MeV and 50 MeV minimally scattered, uncollimated electron beams from a racetrack microtron. Source distributions for the Monte Carlo calculations were reconstructed from in-air ion chamber scans and then benchmarked against measurements in a homogeneous water phantom. The in-air spatial distributions were found to have FWHM of 4.7 cm and 1.3 cm, at 100 cm from the source, for the 10 MeV and 50 MeV beams respectively. Energy spectra for the electron beams were determined by simulating the components of the microtron treatment head using the code MCNP4B. Profile measurements were made using an ion chamber in a water phantom with slabs of lung or bone-equivalent materials submerged at various depths. DPM calculations are, on average, within 2% agreement with measurement for all geometries except for the 50 MeV incident on a 6 cm lung-equivalent slab. Measurements using approximately monoenergetic, 50 MeV, 'pencil-beam'-type electrons in heterogeneous media provide conditions for maximum electronic disequilibrium and hence present a stringent test of the code's electron transport physics; the agreement noted between calculation and measurement illustrates that the DPM code is capable of accurate dose calculation even under such conditions. (author)

  13. Isomer beam elastic scattering: 26mAl(p, p) for astrophysics

    Science.gov (United States)

    Kahl, D.; Shimizu, H.; Yamaguchi, H.; Abe, K.; Beliuskina, O.; Cha, S. M.; Chae, K. Y.; Chen, A. A.; Ge, Z.; Hayakawa, S.; Imai, N.; Iwasa, N.; Kim, A.; Kim, D. H.; Kim, M. J.; Kubono, S.; Kwag, M. S.; Liang, J.; Moon, J. Y.; Nishimura, S.; Oka, S.; Park, S. Y.; Psaltis, A.; Teranishi, T.; Ueno, Y.; Yang, L.

    2018-01-01

    The advent of radioactive ground-state beams some three decades ago ultimately sparked a revolution in our understanding of nuclear physics. However, studies with radioactive isomer beams are sparse and have often required sophisticated apparatuses coupled with the technologies of ground-state beams due to typical mass differences on the order of hundreds of keV and vastly different lifetimes for isomers. We present an application of a isomeric beam of 26mAl to one of the most famous observables in nuclear astrophysics: galactic 26Al. The characteristic decay of 26Al in the Galaxy was the first such specific radioactivity to be observed originating from outside the Earth some four decades ago. We present a newly-developed, novel technique to probe the structure of low-spin states in 27Si. Using the Center for Nuclear Study low-energy radioisotope beam separator (CRIB), we report on the measurement of 26mAl proton resonant elastic scattering conducted with a thick target in inverse kinematics. The preliminary results of this on-going study are presented.

  14. Dosimetry and LET spectrometry in C 290 MeV/n and Ne 400 MeV/n HIMAC ion beam by different TLD's, TED based LET spectrometers, and Si energy-deposition spectrometer

    International Nuclear Information System (INIS)

    Spurny, F.; Brabcova, K.; Jadrnickova, I.; Uchihori, Y.; Kitamura, H.; Yasuda, N.; Molokanov, A. G.

    2009-01-01

    The sets of track etched detectors based (TED) spectrometer's of the linear energy transfer (LET) have been, together with two types of thermoluminescent detectors (TLD)and MDU- Liulin energy deposition spectrometer exposed in the C 290 MeV/n and Ne 400 MeV/n ion beams at the HlMAC installation at NIRS, Chiba, Japan. The experiment has been performed in the frame of NPI project 20P241 agreed by HlMAC P AC at the beginning of 2008 year. Up to now, moxstle only results obtained in C-ion beam have been treated and analyzed. Sets of TED spectrometer's and TLD detectors have been exposed in 19 depths in the C-ion beam with expected LET values of primary particles from 13 keV/μm in water, through the Bragg peak area up to two depth behind the Bragg peak. The contribution of fragments to total number of events, and to the energy absorbed in Si has been determined, when possible separately for different fragments. In all cases also total contribution of fragments (and other secondary particles) to the total number of energy deposition events and to the absorbed dose has been estimated. LET and energy deposition spectra obtained will be compared together , a good agreement of data has bee stated. Some of results have been also compared with those obtained by calculation by means of PHITS code. (authors)

  15. High resolution time-of-flight spectrometer for crossed molecular beam study of elementary chemical reactions

    International Nuclear Information System (INIS)

    Qiu Minghui; Che Li; Ren Zefeng; Dai Dongxu; Wang Xiuyan; Yang Xueming

    2005-01-01

    In this article, we describe an apparatus in our laboratory for investigating elementary chemical reactions using the high resolution time-of-flight Rydberg tagging method. In this apparatus, we have adopted a rotating source design so that collision energy can be changed for crossed beam studies of chemical reactions. Preliminary results on the HI photodissociation and the F atom reaction with H 2 are reported here. These results suggest that the experimental apparatus is potentially a powerful tool for investigating state-to-state dynamics of elementary chemical reactions

  16. Scatter kernel estimation with an edge-spread function method for cone-beam computed tomography imaging

    International Nuclear Information System (INIS)

    Li Heng; Mohan, Radhe; Zhu, X Ronald

    2008-01-01

    The clinical applications of kilovoltage x-ray cone-beam computed tomography (CBCT) have been compromised by the limited quality of CBCT images, which typically is due to a substantial scatter component in the projection data. In this paper, we describe an experimental method of deriving the scatter kernel of a CBCT imaging system. The estimated scatter kernel can be used to remove the scatter component from the CBCT projection images, thus improving the quality of the reconstructed image. The scattered radiation was approximated as depth-dependent, pencil-beam kernels, which were derived using an edge-spread function (ESF) method. The ESF geometry was achieved with a half-beam block created by a 3 mm thick lead sheet placed on a stack of slab solid-water phantoms. Measurements for ten water-equivalent thicknesses (WET) ranging from 0 cm to 41 cm were taken with (half-blocked) and without (unblocked) the lead sheet, and corresponding pencil-beam scatter kernels or point-spread functions (PSFs) were then derived without assuming any empirical trial function. The derived scatter kernels were verified with phantom studies. Scatter correction was then incorporated into the reconstruction process to improve image quality. For a 32 cm diameter cylinder phantom, the flatness of the reconstructed image was improved from 22% to 5%. When the method was applied to CBCT images for patients undergoing image-guided therapy of the pelvis and lung, the variation in selected regions of interest (ROIs) was reduced from >300 HU to <100 HU. We conclude that the scatter reduction technique utilizing the scatter kernel effectively suppresses the artifact caused by scatter in CBCT.

  17. Transverse Beam Spin Asymmetries in Forward-Angle Elastic Electron-Proton Scattering

    Energy Technology Data Exchange (ETDEWEB)

    David Armstrong; Francois Arvieux; Razmik Asaturyan; Todd Averett; Stephanie Bailey; Guillaume Batigne; Douglas Beck; Elizabeth Beise; Jay Benesch; Louis Bimbot; James Birchall; Angela Biselli; Peter Bosted; Elodie Boukobza; Herbert Breuer; Roger Carlini; Robert Carr; Nicholas Chant; Yu-Chiu Chao; Swapan Chattopadhyay; Russell Clark; Silviu Covrig; Anthony Cowley; Daniel Dale; Charles Davis; Willie Falk; John Finn; Tony Forest; Gregg Franklin; Christophe Furget; David Gaskell; Joseph Grames; Keith Griffioen; Klaus Grimm; Benoit Guillon; Hayko Guler; Lars Hannelius; Richard HASTY; Alice Hawthorne Allen; Tanja Horn; Kathleen Johnston; Mark Jones; Peter Kammel; Reza Kazimi; Paul King; Ameya Kolarkar; Elie Korkmaz; Wolfgang Korsch; Serge Kox; Joachim Kuhn; Jeff Lachniet; Lawrence Lee; Jason Lenoble; Eric Liatard; Jianglai Liu; Berenice Loupias; Allison Lung; Dominique Marchand; Jeffery Martin; Kenneth McFarlane; David McKee; Robert McKeown; Fernand Merchez; Hamlet Mkrtchyan; Bryan Moffit; M. Morlet; Itaru Nakagawa; Kazutaka Nakahara; Retief Neveling; Silvia Niccolai; S. Ong; Shelley Page; Vassilios Papavassiliou; Stephen Pate; Sarah Phillips; Mark Pitt; Benard Poelker; Tracy Porcelli; Gilles Quemener; Brian Quinn; William Ramsay; Aamer Rauf; Jean-Sebastien Real; Julie Roche; Philip Roos; Gary Rutledge; Jeffery Secrest; Neven Simicevic; Gregory Smith; Damon Spayde; Samuel Stepanyan; Marcy Stutzman; Vince Sulkosky; Vincent Sulkosky; Vince Sulkosky; Vincent Sulkosky; Vardan Tadevosyan; Raphael Tieulent; Jacques Van de Wiele; Willem van Oers; Eric Voutier; William Vulcan; Glen Warren; Steven Wells; Steven Williamson; Stephen Wood; Chen Yan; Junho Yun; Valdis Zeps

    2007-08-01

    We have measured the beam-normal single-spin asymmetry in elastic scattering of transversely-polarized 3 GeV electrons from unpolarized protons at Q^2 values of 0.15 and 0.25 (GeV/c)^2 with results of A_n = -4.06 +- 0.99(stat) +- 0.63(syst) and A_n = -4.82 +- 1.87(stat) +- 0.98(syst) ppm. These results are inconsistent with calculations solely using the elastic nucleon intermediate state, and generally agree with calculations with significant inelastic hadronic intermediate state contributions. A_n provides a direct probe of the imaginary component of the two-photon exchange amplitude, the complete description of which is important in the interpretation of data from precision electron-scattering experiments.

  18. Time-dependent Second Order Scattering Theory for Weather Radar with a Finite Beam Width

    Science.gov (United States)

    Kobayashi, Satoru; Tanelli, Simone; Im, Eastwood; Ito, Shigeo; Oguchi, Tomohiro

    2006-01-01

    Multiple scattering effects from spherical water particles of uniform diameter are studied for a W-band pulsed radar. The Gaussian transverse beam-profile and the rectangular pulse-duration are used for calculation. An second-order analytical solution is derived for a single layer structure, based on a time-dependent radiative transfer theory as described in the authors' companion paper. When the range resolution is fixed, increase in footprint radius leads to increase in the second order reflectivity that is defined as the ratio of the second order return to the first order one. This feature becomes more serious as the range increases. Since the spaceborne millimeter-wavelength radar has a large footprint radius that is competitive to the mean free path, the multiple scattering effect must be taken into account for analysis.

  19. UCN up-scattering as a source of highly intense monochromatic pulsed beams

    International Nuclear Information System (INIS)

    Rauch, H.; Geltenborg, P.; Zimmer, O.

    2011-01-01

    The present proposal opens new possibilities to increase the usable neutron flux by advanced neutron cooling and phase space transformation methods. Thus a new instrument should be installed where the available neutron flux is used more efficiently. The essential point is an increase of phase space density and brilliance due to a more effective production of ultra-cold neutrons and a following transformation of these neutrons to higher energies. Recently reported progresses in the production of UCN's and in the up-scattering of such neutrons make the time mature to step towards a new method to produce high intense pulsed neutron beams. The up-scattering is made by fast moving Bragg crystals

  20. Electromagnetic scattering of a vector Bessel beam in the presence of an impedance cone

    KAUST Repository

    Salem, Mohamed

    2013-07-01

    The electromagnetic field scattering of a vector Bessel beam in the presence of an infinite circular cone with an impedance boundary on its surface is considered. The impinging field is normal to the tip of the cone and is expanded in terms of vector spherical wave functions; a Kontorovich-Lebedev (KL) transform is employed to expand the scattered fields. The problem is reduced to a singular integral equation with a variable coefficient of the non-convolution type. The singularities of the spectral function are deduced and representations for the field at the tip of the cone as well as other regions are given together with the conditions of validity of these representations. © 2013 IEEE.

  1. New X-ray beam position monitors with submicron resolution utilizing imaging of scattered X-rays at CHESS

    International Nuclear Information System (INIS)

    Revesz, Peter; Temnykh, Alexander B.; Pauling, Alan K.

    2011-01-01

    At CHESS' A, F and G wiggler beam lines three new video beam position monitors (VBPMs) have been commissioned. These new VBPMs utilize X-rays scattered from the graphite filter (A and F line) or from a beryllium window (G-line) as the white wiggler beam passes through them. As the X-rays scatter in all directions from the scattering medium, a slit camera creates an image of the beam's footprint on a fluorescent screen. This image is then viewed by a CCD camera and analyzed using a computer program to calculate the intensity centroid, the beam profile and integrated intensity. These data are delivered to the CHESS signal archiving system for storage and display. The new systems employ digital cameras. These cameras are free of the noise inherent to the analog systems with long video signal connections. As a result, the beam position data delivered by the new systems are more reliable and accurate as shown by beam position traces using different beam position monitors on the same beam line.

  2. New X-ray beam position monitors with submicron resolution utilizing imaging of scattered X-rays at CHESS

    Energy Technology Data Exchange (ETDEWEB)

    Revesz, Peter, E-mail: pr20@cornell.edu [Cornell University, Cornell High Energy Synchrotron Source, Ithaca 14850, NY (United States); Temnykh, Alexander B. [Cornell University, Laboratory for Elem-Particle Physics, Ithaca 14850, NY (United States); Pauling, Alan K. [Cornell University, Cornell High Energy Synchrotron Source, Ithaca 14850, NY (United States)

    2011-09-01

    At CHESS' A, F and G wiggler beam lines three new video beam position monitors (VBPMs) have been commissioned. These new VBPMs utilize X-rays scattered from the graphite filter (A and F line) or from a beryllium window (G-line) as the white wiggler beam passes through them. As the X-rays scatter in all directions from the scattering medium, a slit camera creates an image of the beam's footprint on a fluorescent screen. This image is then viewed by a CCD camera and analyzed using a computer program to calculate the intensity centroid, the beam profile and integrated intensity. These data are delivered to the CHESS signal archiving system for storage and display. The new systems employ digital cameras. These cameras are free of the noise inherent to the analog systems with long video signal connections. As a result, the beam position data delivered by the new systems are more reliable and accurate as shown by beam position traces using different beam position monitors on the same beam line.

  3. XPS and ion beam scattering studies of leaching in simulated waste glass containing uranium

    International Nuclear Information System (INIS)

    Karim, D.P.; Pronko, P.P.; Marcuso, T.L.M.; Lam, D.J.; Paulikas, A.P.

    1980-01-01

    Glass samples (consisting of 2 mole % UO 3 dissolved in a number of complex borosilicate simulated waste glasses including Battelle 76-68) were leached for varying times in distilled water at 75 0 C. The glass surfaces were examined before and after leaching using x-ray photoemission spectroscopy and back-scattered ion beam profiling. Leached samples showed enhanced surface layer concentrations of several elements including uranium, titanium, zinc, iron and rare earths. An experiment involving the leaching of two glasses in the same vessel showed that the uranium surface enhancement is probably not due to redeposition from solution

  4. Analytical description of photon beam phase spaces in inverse Compton scattering sources

    Directory of Open Access Journals (Sweden)

    C. Curatolo

    2017-08-01

    Full Text Available We revisit the description of inverse Compton scattering sources and the photon beams generated therein, emphasizing the behavior of their phase space density distributions and how they depend upon those of the two colliding beams of electrons and photons. The main objective is to provide practical formulas for bandwidth, spectral density, brilliance, which are valid in general for any value of the recoil factor, i.e. both in the Thomson regime of negligible electron recoil, and in the deep Compton recoil dominated region, which is of interest for gamma-gamma colliders and Compton sources for the production of multi-GeV photon beams. We adopt a description based on the center of mass reference system of the electron-photon collision, in order to underline the role of the electron recoil and how it controls the relativistic Doppler/boost effect in various regimes. Using the center of mass reference frame greatly simplifies the treatment, allowing us to derive simple formulas expressed in terms of rms momenta of the two colliding beams (emittance, energy spread, etc. and the collimation angle in the laboratory system. Comparisons with Monte Carlo simulations of inverse Compton scattering in various scenarios are presented, showing very good agreement with the analytical formulas: in particular we find that the bandwidth dependence on the electron beam emittance, of paramount importance in Thomson regime, as it limits the amount of focusing imparted to the electron beam, becomes much less sensitive in deep Compton regime, allowing a stronger focusing of the electron beam to enhance luminosity without loss of mono-chromaticity. A similar effect occurs concerning the bandwidth dependence on the frequency spread of the incident photons: in deep recoil regime the bandwidth comes out to be much less dependent on the frequency spread. The set of formulas here derived are very helpful in designing inverse Compton sources in diverse regimes, giving a

  5. Numerical simulation of Gaussian beam scattering by complex particles of arbitrary shape and structure

    International Nuclear Information System (INIS)

    Han, Y.P.; Cui, Z.W.; Gouesbet, G.

    2012-01-01

    An efficient numerical method based on the surface integral equations is introduced to simulate the scattering of Gaussian beam by complex particles that consist of an arbitrarily shaped host particle and multiple internal inclusions of arbitrary shape. In particular, the incident focused Gaussian beam is described by the Davis fifth-order approximate expressions in combination with rotation defined by Euler angles. The established surface integral equations are discretized with the method of moments, where the unknown equivalent electric and magnetic currents induced on the surfaces of the host particle and the internal inclusions are expanded using the Rao-Wilton-Glisson (RWG) basis functions. The resultant matrix equations are solved by using the parallel conjugate gradient method. The proposed numerical method is validated and its capability illustrated in several characteristic examples.

  6. From x-ray telescopes to neutron scattering: Using axisymmetric mirrors to focus a neutron beam

    International Nuclear Information System (INIS)

    Khaykovich, B.; Gubarev, M.V.; Bagdasarova, Y.; Ramsey, B.D.; Moncton, D.E.

    2011-01-01

    We demonstrate neutron beam focusing by axisymmetric mirror systems based on a pair of mirrors consisting of a confocal ellipsoid and hyperboloid. Such a system, known as a Wolter mirror configuration, is commonly used in X-ray telescopes. The axisymmetric Wolter geometry allows nesting of several mirror pairs to increase collection efficiency. We implemented a system containing four nested Ni mirror pairs, which was tested by the focusing of a polychromatic neutron beam at the MIT Reactor. In addition, we have carried out extensive ray-tracing simulations of the mirrors and their performance in different situations. The major advantages of the Wolter mirrors are nesting for large angular collection and aberration-free performance. We discuss how these advantages can be utilized to benefit various neutron scattering methods, such as imaging, SANS, and time-of-flight spectroscopy.

  7. Cross-correlation time-of-flight analysis of molecular beam scattering

    International Nuclear Information System (INIS)

    Nowikow, C.V.; Grice, R.

    1979-01-01

    The theory of the cross-correlation method of time-of-flight analysis is presented in a form which highlights its formal similarity to the conventional method. A time-of-flight system for the analysis of crossed molecular beam scattering is described, which is based on a minicomputer interface and can operate in both the cross-correlation and conventional modes. The interface maintains the synchronisation of chopper disc rotation and channel advance indefinitely in the cross-correlation method and can acquire data in phase with the beam modulation in both methods. The shutter function of the cross-correlation method is determined and the deconvolution analysis of the data is discussed. (author)

  8. Extension of geometrical-optics approximation to on-axis Gaussian beam scattering. I. By a spherical particle.

    Science.gov (United States)

    Xu, Feng; Ren, Kuan Fang; Cai, Xiaoshu

    2006-07-10

    The geometrical-optics approximation of light scattering by a transparent or absorbing spherical particle is extended from plane wave to Gaussian beam incidence. The formulas for the calculation of the phase of each ray and the divergence factor are revised, and the interference of all the emerging rays is taken into account. The extended geometrical-optics approximation (EGOA) permits one to calculate the scattering diagram in all directions from 0 degrees to 180 degrees. The intensities of the scattered field calculated by the EGOA are compared with those calculated by the generalized Lorenz-Mie theory, and good agreement is found. The surface wave effect in Gaussian beam scattering is also qualitatively analyzed by introducing a flux ratio factor. The approach proposed is particularly important to the further extension of the geometrical-optics approximation to the scattering of large spheroidal particles.

  9. Beam Diagnostics of the Compton Scattering Chamber in Jefferson Lab's Hall C

    Science.gov (United States)

    Faulkner, Adam; I&C Group Collaboration

    2013-10-01

    Upcoming experimental runs in Hall C will utilize Compton scattering, involving the construction and installation of a rectangular beam enclosure. Conventional cylindrical stripline-style Beam Position Monitors (BPMs) are not appropriate due to their form factor; therefore to facilitate measurement of position, button-style BPMs are being considered due to the ease of placement within the new beam enclosure. Button BPM experience is limited at JLAB, so preliminary measurements are needed to characterize the field response, and guide the development of appropriate algorithms for the Analog to Digital receiver systems. -field mapping is performed using a Goubau Line (G-Line), which employs a surface wave to mimic the electron beam, helping to avoid problems associated with vacuum systems. Potential algorithms include simplistic 1/r modeling (-field mapping), look-up-tables, as well as a potential third order power series fit. In addition, the use of neural networks specifically the multi-layer Perceptron will be examined. The models, sensor field maps, and utility of the neural network will be presented. Next steps include: modification of the control algorithm, as well as to run an in-situ test of the four Button electrodes inside of a mock beam enclosure. The analysis of the field response using Matlab suggests the button BPMs are accurate to within 10 mm, and may be successful for beam diagnostics in Hall C. More testing is necessary to ascertain the limitations of the new electrodes. The National Science Foundation, Old Dominion University, The Department of Energy, and Jefferson Lab.

  10. Scattered hard X-ray and γ-ray generation from a chromatic electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Coleman, J. E. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Welch, D. R.; Miller, C. L. [Voss Scientific, Albuquerque, New Mexico 87108 (United States)

    2015-11-14

    An array of photon diagnostics has been deployed on a high power relativistic electron beam diode. Electrons are extracted through a 17.8 cm diode from the surface discharge of a carbon fiber velvet cathode with a nominal diode voltage of 3.8 MV. <10% of the 100 ns electron pulse is composed of off energy electrons (1–3 MeV) accelerated during the rise and fall of the pulse that impact the stainless steel beam pipe and generate a Bremsstrahlung spectrum of 0.1–3 MeV photons with a total count of 10{sup 11}. The principal objective of these experiments is to quantify the electron beam dynamics and spatial dynamics of the hard X-ray and γ-ray flux generated in the diode region. A qualitative comparison of experimental and calculated results are presented, including time and energy resolved electron beam propagation and scattered photon measurements with X-ray PIN diodes and a photomultiplier tube indicating a dose dependence on the diode voltage >V{sup 4} and detected photon counts of nearly 10{sup 6} at a radial distance of 1 m which corresponds to dose ∼40 μrad at 1 m.

  11. Multi-GeV electron-positron beam generation from laser-electron scattering.

    Science.gov (United States)

    Vranic, Marija; Klimo, Ondrej; Korn, Georg; Weber, Stefan

    2018-03-16

    The new generation of laser facilities is expected to deliver short (10 fs-100 fs) laser pulses with 10-100 PW of peak power. This opens an opportunity to study matter at extreme intensities in the laboratory and provides access to new physics. Here we propose to scatter GeV-class electron beams from laser-plasma accelerators with a multi-PW laser at normal incidence. In this configuration, one can both create and accelerate electron-positron pairs. The new particles are generated in the laser focus and gain relativistic momentum in the direction of laser propagation. Short focal length is an advantage, as it allows the particles to be ejected from the focal region with a net energy gain in vacuum. Electron-positron beams obtained in this setup have a low divergence, are quasi-neutral and spatially separated from the initial electron beam. The pairs attain multi-GeV energies which are not limited by the maximum energy of the initial electron beam. We present an analytical model for the expected energy cutoff, supported by 2D and 3D particle-in-cell simulations. The experimental implications, such as the sensitivity to temporal synchronisation and laser duration is assessed to provide guidance for the future experiments.

  12. Scatter correction, intermediate view estimation and dose characterization in megavoltage cone-beam CT imaging

    Science.gov (United States)

    Sramek, Benjamin Koerner

    The ability to deliver conformal dose distributions in radiation therapy through intensity modulation and the potential for tumor dose escalation to improve treatment outcome has necessitated an increase in localization accuracy of inter- and intra-fractional patient geometry. Megavoltage cone-beam CT imaging using the treatment beam and onboard electronic portal imaging device is one option currently being studied for implementation in image-guided radiation therapy. However, routine clinical use is predicated upon continued improvements in image quality and patient dose delivered during acquisition. The formal statement of hypothesis for this investigation was that the conformity of planned to delivered dose distributions in image-guided radiation therapy could be further enhanced through the application of kilovoltage scatter correction and intermediate view estimation techniques to megavoltage cone-beam CT imaging, and that normalized dose measurements could be acquired and inter-compared between multiple imaging geometries. The specific aims of this investigation were to: (1) incorporate the Feldkamp, Davis and Kress filtered backprojection algorithm into a program to reconstruct a voxelized linear attenuation coefficient dataset from a set of acquired megavoltage cone-beam CT projections, (2) characterize the effects on megavoltage cone-beam CT image quality resulting from the application of Intermediate View Interpolation and Intermediate View Reprojection techniques to limited-projection datasets, (3) incorporate the Scatter and Primary Estimation from Collimator Shadows (SPECS) algorithm into megavoltage cone-beam CT image reconstruction and determine the set of SPECS parameters which maximize image quality and quantitative accuracy, and (4) evaluate the normalized axial dose distributions received during megavoltage cone-beam CT image acquisition using radiochromic film and thermoluminescent dosimeter measurements in anthropomorphic pelvic and head and

  13. Single particle characterization using a light scattering module coupled to a time-of-flight aerosol mass spectrometer

    Science.gov (United States)

    Cross, E. S.; Onasch, T. B.; Canagaratna, M.; Jayne, J. T.; Kimmel, J.; Yu, X.-Y.; Alexander, M. L.; Worsnop, D. R.; Davidovits, P.

    2008-12-01

    We present the first single particle results obtained using an Aerodyne time-of-flight aerosol mass spectrometer coupled with a light scattering module (LS-ToF-AMS). The instrument was deployed at the T1 ground site approximately 40 km northeast of the Mexico City Metropolitan Area (MCMA) as part of the MILAGRO field study in March of 2006. The instrument was operated as a standard AMS from 12-30 March, acquiring average chemical composition and size distributions for the ambient aerosol, and in single particle mode from 27-30 March. Over a 75-h sampling period, 12 853 single particle mass spectra were optically triggered, saved, and analyzed. The correlated optical and chemical detection allowed detailed examination of single particle collection and quantification within the LS-ToF-AMS. The single particle data enabled the mixing states of the ambient aerosol to be characterized within the context of the size-resolved ensemble chemical information. The particulate mixing states were examined as a function of sampling time and most of the particles were found to be internal mixtures containing many of the organic and inorganic species identified in the ensemble analysis. The single particle mass spectra were deconvolved, using techniques developed for ensemble AMS data analysis, into HOA, OOA, NH4NO3, (NH4)2SO4, and NH4Cl fractions. Average single particle mass and chemistry measurements are shown to be in agreement with ensemble MS and PTOF measurements. While a significant fraction of ambient particles were internal mixtures of varying degrees, single particle measurements of chemical composition allowed the identification of time periods during which the ambient ensemble was externally mixed. In some cases the chemical composition of the particles suggested a likely source. Throughout the full sampling period, the ambient ensemble was an external mixture of combustion-generated HOA particles from local sources (e.g. traffic), with number concentrations peaking

  14. An experimental study of the scatter correction by using a beam-stop-array algorithm with digital breast tomosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ye-Seul; Park, Hye-Suk; Kim, Hee-Joung [Yonsei University, Wonju (Korea, Republic of); Choi, Young-Wook; Choi, Jae-Gu [Korea Electrotechnology Research Institute, Ansan (Korea, Republic of)

    2014-12-15

    Digital breast tomosynthesis (DBT) is a technique that was developed to overcome the limitations of conventional digital mammography by reconstructing slices through the breast from projections acquired at different angles. In developing and optimizing DBT, The x-ray scatter reduction technique remains a significant challenge due to projection geometry and radiation dose limitations. The most common approach to scatter reduction is a beam-stop-array (BSA) algorithm; however, this method raises concerns regarding the additional exposure involved in acquiring the scatter distribution. The compressed breast is roughly symmetric, and the scatter profiles from projections acquired at axially opposite angles are similar to mirror images. The purpose of this study was to apply the BSA algorithm with only two scans with a beam stop array, which estimates the scatter distribution with minimum additional exposure. The results of the scatter correction with angular interpolation were comparable to those of the scatter correction with all scatter distributions at each angle. The exposure increase was less than 13%. This study demonstrated the influence of the scatter correction obtained by using the BSA algorithm with minimum exposure, which indicates its potential for practical applications.

  15. Neutron and synchrotorn x-ray small angle scattering instruments for applications in biology at the Brookhaven National Laboratory

    International Nuclear Information System (INIS)

    Schoenborn, B.P.; Wise, D.S.; Schneider, D.K.

    1983-01-01

    Facilities for small angle x-ray and neutron scattering are described, with emphasis on the characterization of the primary beam of the neutron instrument and the spectrometer control logic of the synchrotron instrument

  16. Interaction of a high-order Bessel beam with a submerged spherical ultrasound contrast agent shell - Scattering theory.

    Science.gov (United States)

    Mitri, F G

    2010-03-01

    Acoustic scattering properties of ultrasound contrast agents are useful in extending existing or developing new techniques for biomedical imaging applications. A useful first step in this direction is to investigate the acoustic scattering of a new class of acoustic beams, known as helicoidal high-order Bessel beams, to improve the understanding of their scattering characteristics by an ultrasound contrast agent, which at present is very limited. The transverse acoustic scattering of a commercially available albuminoidal ultrasound contrast agent shell filled with air or a denser gas such as perfluoropropane and placed in a helicoidal Bessel beam of any order is examined numerically. The shell is assumed to possess an outer radius a=3.5 microns and a thickness of approximately 105 nm. Moduli of the total and resonance transverse acoustic scattering form functions are numerically evaluated in the bandwidth 0scattering of a helicoidal Bessel beam of order m1 so that the dynamics of contrast agents would be significantly altered. The main finding of the present theory is the suppression or enhancement for a particular resonance that may be used to advantage in imaging with ultrasound contrast agents for clinical applications. 2009 Elsevier B.V. All rights reserved.

  17. An experimental study on the influence of scatter and beam hardening in x-ray CT for dimensional metrology

    International Nuclear Information System (INIS)

    Lifton, J J; McBride, J W; Malcolm, A A

    2016-01-01

    Scattered radiation and beam hardening introduce artefacts that degrade the quality of data in x-ray computed tomography (CT). It is unclear how these artefacts influence dimensional measurements evaluated from CT data. Understanding and quantifying the influence of these artefacts on dimensional measurements is required to evaluate the uncertainty of CT-based dimensional measurements. In this work the influence of scatter and beam hardening on dimensional measurements is investigated using the beam stop array scatter correction method and spectrum pre-filtration for the measurement of an object with internal and external cylindrical dimensional features. Scatter and beam hardening are found to influence dimensional measurements when evaluated using the ISO50 surface determination method. On the other hand, a gradient-based surface determination method is found to be robust to the influence of artefacts and leads to more accurate dimensional measurements than those evaluated using the ISO50 method. In addition to these observations the GUM method for evaluating standard measurement uncertainties is applied and the standard measurement uncertainty due to scatter and beam hardening is estimated. (paper)

  18. Multiple scattering of a zero-order Bessel beam with arbitrary incidence by an aggregate of uniaxial anisotropic spheres

    International Nuclear Information System (INIS)

    Li, Z.J.; Wu, Z.S.; Qu, T.; Shang, Q.C.; Bai, L.

    2016-01-01

    Based on the generalized multiparticle Mie theory, multiple scattering of an aggregate of uniaxial anisotropic spheres illuminated by a zero-order Bessel beam (ZOBB) with arbitrary propagation direction is investigated. The particle size and configuration are arbitrary. The arbitrary incident Bessel beam is expanded in terms of spherical vector wave functions (SVWFs). Utilizing the vector addition theorem of SVWFs, interactive and total scattering coefficients are derived through the continuous boundary conditions on which the interaction of the particles is considered. The accuracy of the theory and codes are verified by comparing results with those obtained for arbitrary plane wave incidence by CST simulation, and for ZOBB incidence by a numerical method. The effects of angle of incidence, pseudo-polarization angle, half-conical angle, beam center position, and permittivity tensor elements on the radar cross sections (RCSs) of several types of collective uniaxial anisotropic spheres, such as a linear chain, a 4×4×4 cube-shaped array, and other periodical structures consisting of massive spheres, are numerically analyzed. Selected results on the properties of typical particles such as TiO 2 , SiO 2 , or other particle lattices are calculated. This investigation could provide an effective test for further research on the scattering characteristics of an aggregate of anisotropic spheres by a high-order Bessel vortex beam. The results have important application in optical tweezers and particle manipulation. - Highlights: • Scattering of Bessel beam by an aggregate of uniaxial anisotropic spheres is studied. • The zero-order Bessel beam propagates and polarizes along arbitrary direction. • The accuracy of expansion coefficients, the scattering theory and codes is verified. • Effects of various parameters on scattering properties are numerically discussed. • Scattering properties of several type of periodical array are numerically analyzed.

  19. Precision mechanical design of an ultrahigh-resolution inelastic x-ray scattering spectrometer system with CDFDW optics at the APS

    International Nuclear Information System (INIS)

    Shu, D; Stoupin, S; Khachatryan, R; Goetze, K A; Roberts, T; Shvyd'ko, Y; Mundboth, K; Collins, S

    2013-01-01

    There are many scientific applications, especially involving topics related to the equilibrium atomic-scale dynamics of condensed matter, that require both a narrower and a steeper resolution function and access to a broader dynamic range than are currently available. To meet these important scientific needs, a prototype of a novel ultrahigh-resolution inelastic x-ray scattering spectrometer system has been designed and constructed at undulator-based beamline 30-ID at the Advanced Photon Source, Argonne National Laboratory. This prototype is designed to meet challenging mechanical and optical specifications for performing so-called CDFDW angular-dispersive x-ray crystal optics, which include a central ultra-thin CFW crystal and a pair of dispersing elements. The abbreviation CDFDW stands for: C – collimating crystal, D – dispersing-element crystal (two D-crystals are used in each CDFDW), F – anomalous transmission filter, and W – wavelength-selector crystal [1]. The mechanical design of the ultrahigh-resolution inelastic x-ray scattering spectrometer, as well as the preliminary test results of its precision positioning performance are presented in this paper.

  20. Multiple-scattering analysis of laser-beam propagation in the atmosphere and through obscurants

    International Nuclear Information System (INIS)

    Zardecki, A.; Gerstl, S.A.W.

    1983-01-01

    The general purpose, discrete-ordinates transport code TWOTRAN is applied to describe the propagation and multiple scattering of a laser beam in a nonhomogeneous aerosol medium. For the medium composed of smoke, haze, and a rain cloud, the problem of the target detectability in a realistic atmospheric scenario is addressed and solved. The signals reflected from the target vs the signals scattered from the smoke cloud are analyzed as a function of the smoke concentration. By calculating the average intensity and a correction factor in the x-y and r-z geometries, the consistency of the rectangular and cylindrical geometry models is assessed. Received power for a detector with a small field of view is computed on a sphere of 1-km radius around the laser source for the Air Force Geophysics Laboratory rural aerosol model with extinction coefficients of 4 km - 1 and 10 km - 1 . This computation allows us to study the received power as a function of the angle between the detector and source axes. The correction factor describing the multiple-scattering enhancement with respect to the simple Lambert-Beer law is introduced, and its calculation is employed to validate the use of the small-angle approximation for the transmissometer configuration. An outline of the theory for a finite field of view detector is followed by numerical results pertaining to the received power and intensity for various aerosol models. Recommendations regarding future work are also formulated

  1. Bremsstrahlung scattering calculations for the beam stops and collimators in the APS insertion-device beamlines

    International Nuclear Information System (INIS)

    Job, P.K.; Haeffner, D.R.; Shu, D.

    1994-12-01

    Bremsstrahlung is produced in the APS storage ring by the interaction of positrons with the residual gas molecules in the vacuum chamber of the storage ring. The bremsstrahlung production causes a serious challenge in shielding the insertion-device beamlines because the entire straight section (15 meters) is in the line of sight of the beamline. The radiation emerges in a narrow cone tangential to the beam path with the characteristic emission angle 1/γ, where γ is E/mc 2 which is the ratio of the kinetic energy to the rest mass for the positrons. This high-energy gamma radiation has an approximate 1/E spectrum with the maximum energy extending up to the particle energy (7 GeV for the APS). Bremsstrahlung, being high-energy photons, produces an electromagnetic shower when it encounters the beamline elements. A beamline element not thick enough to fully contain an electromagnetic shower can cause considerable scatter of the high-energy bremsstrahlung radiation. The low-energy component of the bremsstrahlung can also be scattered and create high dose rates in the first-optical and white-beam enclosures. The fully developed electromagnetic shower will have a photon spectrum almost independent of the material. The electromagnetic showers in the high-Z materials can also produce photoneutrons. This note reports the summary of EGS4 calculations performed on bremsstrahlung scattering from different beamline components in a typical APS insertion-device beamline. The related recommendations for shielding are also given. The shielding criterion adopted is a total dose rate of 2.5μSv/h (0.25 mrem/h) at 30 cm from the shield

  2. Scattering of field-aligned beam ions upstream of Earth's bow shock

    Directory of Open Access Journals (Sweden)

    A. Kis

    2007-03-01

    Full Text Available Field-aligned beams are known to originate from the quasi-perpendicular side of the Earth's bow shock, while the diffuse ion population consists of accelerated ions at the quasi-parallel side of the bow shock. The two distinct ion populations show typical characteristics in their velocity space distributions. By using particle and magnetic field measurements from one Cluster spacecraft we present a case study when the two ion populations are observed simultaneously in the foreshock region during a high Mach number, high solar wind velocity event. We present the spatial-temporal evolution of the field-aligned beam ion distribution in front of the Earth's bow shock, focusing on the processes in the deep foreshock region, i.e. on the quasi-parallel side. Our analysis demonstrates that the scattering of field-aligned beam (FAB ions combined with convection by the solar wind results in the presence of lower-energy, toroidal gyrating ions at positions deeper in the foreshock region which are magnetically connected to the quasi-parallel bow shock. The gyrating ions are superposed onto a higher energy diffuse ion population. It is suggested that the toroidal gyrating ion population observed deep in the foreshock region has its origins in the FAB and that its characteristics are correlated with its distance from the FAB, but is independent on distance to the bow shock along the magnetic field.

  3. Scattering of field-aligned beam ions upstream of Earth's bow shock

    Directory of Open Access Journals (Sweden)

    A. Kis

    2007-03-01

    Full Text Available Field-aligned beams are known to originate from the quasi-perpendicular side of the Earth's bow shock, while the diffuse ion population consists of accelerated ions at the quasi-parallel side of the bow shock. The two distinct ion populations show typical characteristics in their velocity space distributions. By using particle and magnetic field measurements from one Cluster spacecraft we present a case study when the two ion populations are observed simultaneously in the foreshock region during a high Mach number, high solar wind velocity event. We present the spatial-temporal evolution of the field-aligned beam ion distribution in front of the Earth's bow shock, focusing on the processes in the deep foreshock region, i.e. on the quasi-parallel side. Our analysis demonstrates that the scattering of field-aligned beam (FAB ions combined with convection by the solar wind results in the presence of lower-energy, toroidal gyrating ions at positions deeper in the foreshock region which are magnetically connected to the quasi-parallel bow shock. The gyrating ions are superposed onto a higher energy diffuse ion population. It is suggested that the toroidal gyrating ion population observed deep in the foreshock region has its origins in the FAB and that its characteristics are correlated with its distance from the FAB, but is independent on distance to the bow shock along the magnetic field.

  4. Dual aerosol detector based on forward light scattering with a single laser beam

    International Nuclear Information System (INIS)

    Kovach, B.J.; Custer, R.A.; Powers, F.L.; Kovach, A.

    1985-01-01

    The in-place leak testing of HEPA filter banks using a single detector can lead to some error in the measurement due to the fluctuation of the aerosol concentration while the single detector is being switched from the upstream to downstream sampling. The time duration of the test also can cause unnecessarily high DOP loading of the HEPA filters and in some cases higher radiation exposure to the testing personnel. The new forward light scattering detector uses one 632.8 nm laser beam for aerosol detection in a dual chamber sampling and detecting aerosol concentration simultaneously both upstream and downstream. This manner of operation eliminates the errors caused by concentration variations between upstream and downstream sample points while the switching takes place. The new detector uses large area silicone photodiodes with a hole in the center, to permit uninterrupted passage of the laser beam through the downstream sample chamber. The nonlinearity due to the aerosol over population of the laser beam volume is calculated to be less than 1% using a Poisson distribution method to determine the average distance of the particles. A simple pneumatic system prevents mixing of the upstream and downstream samples even in wide pressure variations of the duct system

  5. Photoacoustic Soot Spectrometer (PASS) Instrument Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Dubey, M [Los Alamos National Laboratory; Springston, S [Brookhaven National Laboratory; Koontz, A [Pacific Northwest National Laboratory; Aiken, A [Los Alamos National Laboratory

    2013-01-17

    The photoacoustic soot spectrometer (PASS) measures light absorption by aerosol particles. As the particles pass through a laser beam, the absorbed energy heats the particles and in turn the surrounding air, which sets off a pressure wave that can be detected by a microphone. The PASS instruments deployed by ARM can also simultaneously measure the scattered laser light at three wavelengths and therefore provide a direct measure of the single-scattering albedo. The Operator Manual for the PASS-3100 is included here with the permission of Droplet Measurement Technologies, the instrument’s manufacturer.

  6. Problems in nonlinear acoustics: Scattering of sound by sound, parametric receiving arrays, nonlinear effects in asymmetric sound beams and pulsed finite amplitude sound beams

    Science.gov (United States)

    Hamilton, Mark F.

    1989-08-01

    Four projects are discussed in this annual summary report, all of which involve basic research in nonlinear acoustics: Scattering of Sound by Sound, a theoretical study of two nonconlinear Gaussian beams which interact to produce sum and difference frequency sound; Parametric Receiving Arrays, a theoretical study of parametric reception in a reverberant environment; Nonlinear Effects in Asymmetric Sound Beams, a numerical study of two dimensional finite amplitude sound fields; and Pulsed Finite Amplitude Sound Beams, a numerical time domain solution of the KZK equation.

  7. Experimental considerations concerning the velocity measurement of the relativistic electron beam in a gyrotron by means of Thomson scattering

    International Nuclear Information System (INIS)

    Siegrist, M.R.; Soumagne, G.; Tran, M.Q.

    1992-11-01

    The feasibility of Thomson scattering to determine the beam velocity in a gyrotron has been analyzed and preliminary experiments to implement such a system on our 100 GHz quasi-optical gyrotron are reported. Although the project had to be abandoned due to technical problems, the conclusions are that for the 90 o scattering arrangement discussed it should be possible to determine at least one velocity component with an acceptable signal-to-noise ratio. (author) 11 figs., 10 refs

  8. Studies on ion scattering and sputtering processes relevant to ion beam sputter deposition of multicomponent thin films

    International Nuclear Information System (INIS)

    Auciello, O.; Ameen, M.S.; Kingon, A.I.

    1989-01-01

    Results from computer simulation and experiments on ion scattering and sputtering processes in ion beam sputter deposition of high Tc superconducting and ferroelectric thin films are presented. It is demonstrated that scattering of neutralized ions from the targets can result in undesirable erosion of, and inert gas incorporation in, the growing films, depending on the ion/target atom ass ratio and ion beam angle of incidence/target/substrate geometry. The studies indicate that sputtering Kr + or Xe + ions is preferable to the most commonly used Ar + ions, since the undesirable phenomena mentioned above are minimized for the first two ions. These results are used to determine optimum sputter deposition geometry and ion beam parameters for growing multicomponent oxide thin films by ion beam sputter-deposition. 10 refs., 5 figs

  9. SU-F-J-149: Beam and Cryostat Scatter Characteristics of the Elekta MR-Linac

    Energy Technology Data Exchange (ETDEWEB)

    Duglio, M; Towe, S; Roberts, D [Elekta Limited, Crawley, West Sussex (United Kingdom)

    2016-06-15

    Purpose: The Elekta MR-Linac combines a digital linear accelerator system with a 1.5T Philips MRI machine. This study aimed to determine key characteristic information regarding the MR-Linac beam and in particular it evaluated the effect of the MR cryostat on the out of field scatter dose. Methods: Tissue phantom ratios, profiles and depth doses were acquired in plastic water with an IC-profiler or with an MR compatible water tank using multiple system configurations (Full (B0= 1.5T), Full (B0=0T) and No cryostat). Additionally, an in-house CAD based Monte Carlo code based on Penelope was used to provide comparative data. Results: With the cryostat in place and B0=0T, the measured TPR for the MR Linac system was 0.702, indicating an energy of around 7MV. Without the cryostat, the measured TPR was 0.669. For the Full (B0=0T) case, out of field dose at a depth of 10 cm in the isocentric plane, 5 cm from the field edge was 0.8%, 3.1% and 5.4% for 3×3 cm{sup 2}, 10×10 cm{sup 2} and 20×20 cm{sup 2} fields respectively.The out of field dose (averaged between 5 cm and 10 cm beyond the field edges) in the “with cryostat” case is 0.78% (absolute difference) higher than without the cryostat for clinically relevant field sizes (i.e. 10×10 cm{sup 2}) and comparable to measured conventional 6MV treatment beams at a depth of 10 cm (within 0.1% between 5 cm and 6 cm from field edge). At dose maximum and at 5 cm from the field edge, the “with cryostat” out of field scatter for a 10×10 cm{sup 2} field is 1.5% higher than “without cryostat', with a modest increase (0.9%) compared to Agility 6MV in the same conditions. Conclusion: The study has presented typical characteristics of the MR-Linac beam and determined that out of field dose is comparable to conventional treatment beams. All authors are employed by Elekta Ltd., who are developing an MR-Linac.

  10. Simulations of the response function of a plasma ion beam spectrometer for the Cassini mission to Saturn

    International Nuclear Information System (INIS)

    Vilppola, J.H.; Tanskanen, P.J.; Huomo, H.; Barraclough, B.L.

    1996-01-01

    To obtain very high (∼1%) energy resolution with spherical-section electrostatic analyzers requires high precision in both fabrication and in the alignment process. In order to aid in the calibration of the instrument and to help minimize fabrication costs, we have applied simulation models to the ion beam spectrometer for the NASA/ESA Cassini mission to Saturn. Previously we studied the effects of misalignment and simple irregularities of the hemispherical surfaces on the performance of an electrostatic analyzer. We have considered a hemispherical electrostatic analyzer equipped with an aperture plate to collimate the stray electric field at the entrance apertures. The influence of a curved entrance aperture has also been added to the simulation model, and its effects have been studied in detail. A cylindrical three-dimensional simultaneous overrelaxation algorithm has been introduced to solve for the stray electric field. The maximum loss of transmitted particles with respect to the transmission of an ideal instrument has been set at 10%. We demonstrate that the deviation in the distributions of the energies is less than 0.2% and that the deviation in the distributions of entrance angles of transmitted particles is less than 0.1 degree. It has been found that the energy resolution of an electrostatic analyzer can be improved from ΔE/E=(1.6±0.2)% to ΔE/E=(1.3±0.2)% by the introduction of front aperture plates. Through the introduction of curved entrance slits, the azimuthal angle resolution has changed from β=(1.4±0.1)degree for the simplified geometry simulation results of our previous article to β=(2.3±0.1)degree. We have confirmed that an accuracy of 25 μm in the alignment of the two hemispherical surfaces is sufficient to give the instrument the desired resolutions. copyright 1996 American Institute of Physics

  11. Possibilities for direct optical observation of negative hydrogen ions in ion beam plasma sources via Rayleigh or Thomson scattering

    International Nuclear Information System (INIS)

    Burgess, D.D.

    1985-01-01

    The possibilities of applying optical scattering techniques to the determination of H - concentrations in plasma sources relevant to negative ion beam generation are considered. Rayleigh scattering measurements for incident wavelengths just below the H - photoionization limit appear to be only just feasible experimentally. A more promising possibility is observation of the modification in a plasma containing negative ions of the collective ion-feature in Thomson scattering. Numerical predictions of the effects of H - concentration on the spectral distribution of the ion-feature are presented. (author)

  12. Electron-beam lithography of gold nanostructures for surface-enhanced Raman scattering

    KAUST Repository

    Yue, Weisheng

    2012-10-26

    The fabrication of nanostructured substrates with precisely controlled geometries and arrangements plays an important role in studies of surface-enhanced Raman scattering (SERS). Here, we present two processes based on electron-beam lithography to fabricate gold nanostructures for SERS. One process involves making use of metal lift-off and the other involves the use of the plasma etching. These two processes allow the successful fabrication of gold nanostructures with various kinds of geometrical shapes and different periodic arrangements. 4-mercaptopyridine (4-MPy) and Rhodamine 6G (R6G) molecules are used to probe SERS signals on the nanostructures. The SERS investigations on the nanostructured substrates demonstrate that the gold nanostructured substrates have resulted in large SERS enhancement, which is highly dependent on the geometrical shapes and arrangements of the gold nanostructures. © 2012 IOP Publishing Ltd.

  13. Multichannel analysis of He*(21S)+Ne elastic and inelastic scattering in crossed atomic beams

    International Nuclear Information System (INIS)

    Martin, D.W.; Fukuyama, T.; Siska, P.E.

    1990-01-01

    State-to-state elastic and inelastic angular distribution and time-of-flight measurements are reported for the scattering of He*(2 1 S) by Ne in crossed supersonic atom beams at four collision energies in the range 0.6--2.8 kcal/mol. The inelastic collision products He+Ne*(nl), where nl=3d', 4p, 4p', 5s, 5s', and 4d, are scattered predominantly forward with respect to the direction of incidence, except for endothermic states near threshold. The data are analyzed with a numerically exact multichannel curve-crossing model that yields good agreement with experimental cross section branching fractions and total quenching and state-to-state rate constants as well as the angular measurements. The model suggests the importance of intermediate ''chaperone'' states, in which the excited electron is temporarily trapped in a d or f Rydberg Ne orbital, in channeling flux into the 4s' and 5s' upper laser states of Ne by energy transfer from He*(2s 1,3 S)

  14. Experimental study of Rayleigh scattering with a ruby laser beam: relative variation of scattered light with the number of scattering center and the gases nature

    International Nuclear Information System (INIS)

    Bayer, Charles

    1973-06-01

    The experimental variation of the scattered light with the number of scattering centers and with the refraction index of gases is in agreement with the theoretical Rayleigh scattering. A direct calibration System gives the absolute value of the Rayleigh ratio. The experimental value appears to be half of the theoretical one. (author) [fr

  15. Stimulated Raman scattering by an intense relativistic electron beam in a long rippled magnetic field

    International Nuclear Information System (INIS)

    Efthimion, P.C.; Schlesinger, S.P.

    1977-01-01

    For the first time, the parametric coupling of the negative-energy cyclotron and space-charge modes to a fast coaxial waveguide structure is observed. The coaxial waveguide smooth center conductor is internally loaded to maintain a 5% ripple of 1.4-, 1.6-, or 2.0-cm periods on the background axial magnetic field throughout the interaction region of 70 cm. The parametric coupling may be considered a stimulated scattering process with the rippled magnetic field of zero frequency in the lab frame appearing as an electromagnetic pump wave in the beam frame, with 30-MW/cm 2 power density imparting to the electrons a quiver velocity V/sub os/ approx. = 0.1c. As predicted by theory, the frequency of the microwave radiation generated by the negative-energy cyclotron mode decreases with increasing magnetic field while remaining constant for the negative-energy space-charge mode. Power levels from 1 to 5 MW have been measured at mm and cm wavelengths. Radiation at frequencies of 2γ 2 V/L, where V and L are the beam velocity and ripple period, respectively, has been observed at high magnetic fields with an exponential-growth rate consistent with parametric coupling theory. This mechanism could be employed as a tunable generator of millimeter and submillimeter wavelength radiation

  16. Stimulated Raman scattering by an intense relativistic electron beam in a long rippled magnetic field

    International Nuclear Information System (INIS)

    Efthimion, P.C.

    1977-01-01

    For the first time, the parametric coupling of the negative energy cyclotron and space-charge modes to a fast coaxial waveguide structure is observed. The coaxial waveguide smooth center conductor is internally loaded to maintain a 5% ripple of 1.4, 1.6, or 2.0 cm periods on the background axial magnetic field throughout the interaction region of 70 cm. The parametric coupling may be considered a stimulated scattering process with the rippled magnetic field of zero frequency in the laboratory frame appearing as an electromagnetic pump wave in the beam frame, with 30 MW/cm 2 power density imparting to the electrons a quiver velocity V/sub os/ = 0.1 c. As predicted by theory, the frequency of the microwave radiation generated by the negative energy cyclotron mode decreases with increasing magnetic field while remaining constant for the negative energy space-charge mode. Power levels from 1 to 5 MW have been measured at mm and cm wavelengths. Radiation at frequencies 2γ 2 V/L, where V and L are the beam velocity and ripple period respectively, has been observed at high magnetic fields with an exponential growth rate consistent with parametric coupling theory. This mechanism could be employed as a tunable generator of submillimeter and infrared wavelength radiation

  17. Surface-enhanced Raman scattering active gold nanoparticle/nanohole arrays fabricated through electron beam lithography

    Science.gov (United States)

    Wu, Tsunghsueh; Lin, Yang-Wei

    2018-03-01

    Effective surface-enhanced Raman scattering (SERS)-active substrates from gold nanoparticle and gold nanohole arrays were successfully fabricated through electron beam lithography with precise computer-aided control of the unit size and intergap distance. Their SERS performance was evaluated using 4-mercaptobenzoic acid (4-MBA). These gold arrays yielded strong SERS signals under 785 nm laser excitation. The enhancement factors for 4-MBA molecules on the prepared gold nanoparticle and nanohole arrays maxed at 1.08 × 107 and 8.61 × 106, respectively. The observed increase in SERS enhancement was attributed to the localized surface plasmon resonance (LSPR) wavelength shifting toward the near-infrared regime when the gold nanohole diameter increased, in agreement with the theoretical prediction in this study. The contribution of LSPR to the Raman enhancement from nanohole arrays deposited on fluorine-doped tin oxide glass was elucidated by comparing SERS and transmission spectra. This simple fabrication procedure, which entails employing electron beam lithography and the controllability of the intergap distance, suggests highly promising uses of nanohole arrays as functional components in sensing and photonic devices.

  18. Measurement of high-Q2 deep inelastic scattering cross sections with a longitudinally polarised positron beam at HERA

    NARCIS (Netherlands)

    Chekanov, S.; Kooijman, P.

    2006-01-01

    The cross sections for charged and neutral current deep inelastic scattering in e+p collisions with a longitudinally polarised positron beam have been measured using the ZEUS detector at HERA. The results, based on data corresponding to an integrated luminosity of 23.8 pb−1 at , are given for both

  19. Asymmetry measurements in nucleon--nucleon scattering with polarized beams and targets at ZGS to Fermilab energies

    International Nuclear Information System (INIS)

    Yakosawa, A.

    1977-01-01

    Results of various asymmetry measurements in nucleon-nucleon scattering with polarized beams and targets at ZGS energies are presented. A possible direct-channel resonance in the pp system is discussed. Most of the discussion above ZGS energies are aimed at future measurements

  20. List of publications resulting from the Neutron Beam Scattering Programme supported by the Science and Engineering Research Council for 1984

    International Nuclear Information System (INIS)

    1984-12-01

    The paper lists the references of publications resulting from the Neutron Beam Scattering Programme supported by the Science and Engineering Research Council, covering the year 1984, but also including publications from 1983 not given in the previous issue of this listing. (author)

  1. A new method for x-ray scatter correction: first assessment on a cone-beam CT experimental setup

    International Nuclear Information System (INIS)

    Rinkel, J; Gerfault, L; Esteve, F; Dinten, J-M

    2007-01-01

    Cone-beam computed tomography (CBCT) enables three-dimensional imaging with isotropic resolution and a shorter acquisition time compared to a helical CT scanner. Because a larger object volume is exposed for each projection, scatter levels are much higher than in collimated fan-beam systems, resulting in cupping artifacts, streaks and quantification inaccuracies. In this paper, a general method to correct for scatter in CBCT, without supplementary on-line acquisition, is presented. This method is based on scatter calibration through off-line acquisition combined with on-line analytical transformation based on physical equations, to adapt calibration to the object observed. The method was tested on a PMMA phantom and on an anthropomorphic thorax phantom. The results were validated by comparison to simulation for the PMMA phantom and by comparison to scans obtained on a commercial multi-slice CT scanner for the thorax phantom. Finally, the improvements achieved with the new method were compared to those obtained using a standard beam-stop method. The new method provided results that closely agreed with the simulation and with the conventional CT scanner, eliminating cupping artifacts and significantly improving quantification. Compared to the beam-stop method, lower x-ray doses and shorter acquisition times were needed, both divided by a factor of 9 for the same scatter estimation accuracy

  2. Project and construction of energy degrading and scattering plates for electron beam radiotherapy for skin diseases

    International Nuclear Information System (INIS)

    Fonseca, Gabriel Paiva

    2010-01-01

    There are many radiosensitive epidermotropics diseases such as mycosis fungo-ids and the syndrome of Sezary, coetaneous neoplasics originated from type T lymphocytes. Several studies indicate the eradication of the disease when treated with linear accelerators emitting electron beams with energies between 4 to 10 MeV. However, this treatment technique presents innumerable technical challenges since the disease in general reaches all patient's body, becoming necessary not only a very large field size radiation beam, but also deliver superficial doses limited to the skin depth. To reach the uniformity in the dose distribution, many techniques had already been developed. Based on these previous studies and guided by the report no. 23 of the American Association of Physicists in Medi-cine (AAPM), the present study developed an energy scattering and degrading plates and made dosimetry (computational and experimental), supplying subsidies for a future installation of Total Skin Electron Therapy (TSET) at the Servico de Radioterapia do Hospital das Clinicas de Sao Paulo. As part of the plates design, first of all, the energy spectrum of the 6 MeV electron beam of the VARIAN 2100C accelerator was reconstructed through Monte Carlo simulations using the MCNP4C code and based on experimental data. Once the spectrum is built, several materials were analyzed for the plates design based on radial and axial dose distribution, production of rays-x and dose attenuation. The simulation results were validated by experimental measurements in order to obtain a large field of radiation with 200 cm x 80 cm that meets the specifications of the AAPM protocol. (author)

  3. The SPEDE spectrometer

    Science.gov (United States)

    Papadakis, P.; Cox, D. M.; O'Neill, G. G.; Borge, M. J. G.; Butler, P. A.; Gaffney, L. P.; Greenlees, P. T.; Herzberg, R.-D.; Illana, A.; Joss, D. T.; Konki, J.; Kröll, T.; Ojala, J.; Page, R. D.; Rahkila, P.; Ranttila, K.; Thornhill, J.; Tuunanen, J.; Van Duppen, P.; Warr, N.; Pakarinen, J.

    2018-03-01

    The electron spectrometer, SPEDE, has been developed and will be employed in conjunction with the Miniball spectrometer at the HIE-ISOLDE facility, CERN. SPEDE allows for direct measurement of internal conversion electrons emitted in-flight, without employing magnetic fields to transport or momentum filter the electrons. Together with the Miniball spectrometer, it enables simultaneous observation of γ rays and conversion electrons in Coulomb excitation experiments using radioactive ion beams.

  4. Soft X-ray generation via inverse compton scattering between high quality electron beam and high power laser

    International Nuclear Information System (INIS)

    Masakazu Washio; Kazuyuki Sakaue; Yoshimasa Hama; Yoshio Kamiya; Tomoko Gowa; Akihiko Masuda; Aki Murata; Ryo Moriyama; Shigeru Kashiwagi; Junji Urakawa

    2007-01-01

    High quality beam generation project based on High-Tech Research Center Project, which has been approved by Ministry of Education, Culture, Sports, Science and Technology in 1999, has been conducted by advance research institute for science and engineering, Waseda University. In the project, laser photo-cathode RF-gun has been selected for the high quality electron beam source. RF cavities with low dark current, which were made by diamond turning technique, have been successfully manufactured. The low emittance electron beam was realized by choosing the modified laser injection technique. The obtained normalized emmitance was about 3 m.mrad at 100 pC of electron charge. The soft x-ray beam generation with the energy of 370 eV, which is in the energy region of so-called water window, by inverse Compton scattering has been performed by the collision between IR laser and the low emmitance electron beams. (Author)

  5. The contribution to surface dose form air scatter in mega voltage photon beams

    International Nuclear Information System (INIS)

    Carolan, M.G.; Butson, M.; Metcalfe, P.

    1996-01-01

    Full text: The minimisation of surface dose is an important requirement in radiotherapy in order to avoid undesirable skin reactions. For this reason significant effort has been expended to avoid and understand photon and electron scatter in the heads of linear accelerators which may contribute to surface dose. In this study we have examined the contribution to surface dose which arises due to scatter in the air above the patient. Experimental investigations of air contributions are difficult to design and execute. Therefore we have used Monte Carlo calculations to determine the effect that the presence of air has on surface dose. Methods: The Los Alamos Monte Carlo Neutron and Photon transport code, MCNP4A which incorporates the ETRAN electron transport code from the Integrated TIGER Series of codes was used for our simulations. The geometry used in the model was a 30 cm cube of water. The dose was tallied in cylindrical elements of 7 cm diameter along the axis of the photon beam. For the first millimetre along the beam axis in the phantom, the dose was determined at 0.1 mm increments in 0.1 mm thick volumes. For depths between 1.0 mm and 15.0 mm the dose was determined every 1 mm in 1 mm cylindrical volumes. This yields a depth dose profile with fine spatial resolution near the phantom surface. Dose was also tallied at depths of 5.0, 10.0, 15.0 and 20.0 cm. The simulations were done assuming a 6 MV photon source with a diameter of 1.5 cm, a gaussian intensity profile and a photon energy spectrum based on Mohan et al. (Med. Phys. 12 (1985) 592). No accelerator head geometry was modelled. The field size was defined by virtual collimators which were simply thin regions of zero photon importance and therefore do not contribute to photon or electron scatter. All simulations were run for sufficient particle histories (∼2x10 7 - 5x10 7 source photons) to give statistical uncertainties of ≤ 10% and in most cases ≤ 5%. Fields of size 10, 15, 20 and 25 cm were used

  6. SCATTER

    International Nuclear Information System (INIS)

    Broome, J.

    1965-11-01

    The programme SCATTER is a KDF9 programme in the Egtran dialect of Fortran to generate normalized angular distributions for elastically scattered neutrons from data input as the coefficients of a Legendre polynomial series, or from differential cross-section data. Also, differential cross-section data may be analysed to produce Legendre polynomial coefficients. Output on cards punched in the format of the U.K. A. E. A. Nuclear Data Library is optional. (author)

  7. Beam Normal Single Spin Asymmetry in Forward Angle Inelastic Electron-Proton Scattering using the Q-Weak Apparatus

    Energy Technology Data Exchange (ETDEWEB)

    ., Nuruzzaman [Hampton Univ., Hampton, VA (United States)

    2014-12-01

    The Q-weak experiment in Hall-C at the Thomas Jefferson National Accelerator Facility has made the first direct measurement of the weak charge of the proton through the precision measurement of the parity-violating asymmetry in elastic electron-proton scattering at low momentum transfer. There is also a parity conserving Beam Normal Single Spin Asymmetry or transverse asymmetry (B_n) on H_2 with a sin(phi)-like dependence due to two-photon exchange. If the size of elastic B_n is a few ppm, then a few percent residual transverse polarization in the beam, combined with small broken azimuthal symmetries in the detector, would require a few ppb correction to the Q-weak data. As part of a program of B_n background studies, we made the first measurement of B_n in the N-to-Delta(1232) transition using the Q-weak apparatus. The final transverse asymmetry, corrected for backgrounds and beam polarization, was found to be B_n = 42.82 ± 2.45 (stat) ± 16.07 (sys) ppm at beam energy E_beam = 1.155 GeV, scattering angle theta = 8.3 deg, and missing mass W = 1.2 GeV. B_n from electron-nucleon scattering is a unique tool to study the gamma^* Delta Delta form factors, and this measurement will help to improve the theoretical models on beam normal single spin asymmetry and thereby our understanding of the doubly virtual Compton scattering process. To help correct false asymmetries from beam noise, a beam modulation system was implemented to induce small position, angle, and energy changes at the target to characterize detector response to the beam jitter. Two air-core dipoles separated by ~10 m were pulsed at a time to produce position and angle changes at the target, for virtually any tune of the beamline. The beam energy was modulated using an SRF cavity. The hardware and associated control instrumentation will be described in this dissertation. Preliminary detector sensitivities were extracted which helped to reduce the width of the measured asymmetry. The beam modulation system

  8. Rietveld analysis using powder diffraction data with anomalous scattering effect obtained by focused beam flat sample method

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Masahiko, E-mail: masahiko@spring8.or.jp; Katsuya, Yoshio, E-mail: katsuya@spring8.or.jp; Sakata, Osami, E-mail: SAKATA.Osami@nims.go.jp [Synchrotron X-ray Station at SPring-8, National Institute for Materials Science 1-1-1 Kouto, Sayo, Hyogo 679-5198 (Japan)

    2016-07-27

    Focused-beam flat-sample method (FFM) is a new trial for synchrotron powder diffraction method, which is a combination of beam focusing optics, flat shape powder sample and area detectors. The method has advantages for X-ray diffraction experiments applying anomalous scattering effect (anomalous diffraction), because of 1. Absorption correction without approximation, 2. High intensity X-rays of focused incident beams and high signal noise ratio of diffracted X-rays 3. Rapid data collection with area detectors. We applied the FFM to anomalous diffraction experiments and collected synchrotron X-ray powder diffraction data of CoFe{sub 2}O{sub 4} (inverse spinel structure) using X-rays near Fe K absorption edge, which can distinguish Co and Fe by anomalous scattering effect. We conducted Rietveld analyses with the obtained powder diffraction data and successfully determined the distribution of Co and Fe ions in CoFe{sub 2}O{sub 4} crystal structure.

  9. Rietveld analysis using powder diffraction data with anomalous scattering effect obtained by focused beam flat sample method

    International Nuclear Information System (INIS)

    Tanaka, Masahiko; Katsuya, Yoshio; Sakata, Osami

    2016-01-01

    Focused-beam flat-sample method (FFM) is a new trial for synchrotron powder diffraction method, which is a combination of beam focusing optics, flat shape powder sample and area detectors. The method has advantages for X-ray diffraction experiments applying anomalous scattering effect (anomalous diffraction), because of 1. Absorption correction without approximation, 2. High intensity X-rays of focused incident beams and high signal noise ratio of diffracted X-rays 3. Rapid data collection with area detectors. We applied the FFM to anomalous diffraction experiments and collected synchrotron X-ray powder diffraction data of CoFe_2O_4 (inverse spinel structure) using X-rays near Fe K absorption edge, which can distinguish Co and Fe by anomalous scattering effect. We conducted Rietveld analyses with the obtained powder diffraction data and successfully determined the distribution of Co and Fe ions in CoFe_2O_4 crystal structure.

  10. Patient-specific scatter correction in clinical cone beam computed tomography imaging made possible by the combination of Monte Carlo simulations and a ray tracing algorithm

    DEFF Research Database (Denmark)

    Slot Thing, Rune; Bernchou, Uffe; Mainegra-Hing, Ernesto

    2013-01-01

    Abstract Purpose. Cone beam computed tomography (CBCT) image quality is limited by scattered photons. Monte Carlo (MC) simulations provide the ability of predicting the patient-specific scatter contamination in clinical CBCT imaging. Lengthy simulations prevent MC-based scatter correction from...

  11. First results from PHAROS, the new chopper spectrometer at LANSCE

    International Nuclear Information System (INIS)

    Olivier, B.J.; Sandoval, J.P.; Lysaght, P.; Nutter, M.; Robinson, R.A.

    1993-01-01

    In this article we present the first experimental measurements obtained on PHAROS during the 1992 run cycle at LANSCE. These are data on the phasing of the choppers relative to the accelerator system along with the consequent neutronic resolution, data on the real-space position resolution of the main detectors, a white-beam nickel powder calibration, and our first inelastic scattering measurement made on TiH 2 with an incident energy of 300 MeV. The characteristic features of the new chopper spectrometer PHAROS, designed for low-angle inelastic neutron scattering and neutron Brillouin scattering, are described elsewhere in these proceedings

  12. Triple axis spectrometers

    International Nuclear Information System (INIS)

    Clausen, K.N.

    1997-01-01

    Conventional triple-axis neutron spectroscopy was developed by Brockhouse over thirty years ago' and remains today a versatile and powerful tool for probing the dynamics of condensed matter. The original design of the triple axis spectrometer is technically simple and probes momentum and energy space on a point-by-point basis. This ability to systematically probe the scattering function in a way which only requires a few angles to be moved under computer control and where the observed data in general can be analysed using a pencil and graph paper or a simple fitting routine, has been essential for the success of the method. These constraints were quite reasonable at the time the technique was developed. Advances in computer based data acquisition, neutron beam optics, and position sensitive area detectors have been gradually implemented on many triple axis spectrometer spectrometers, but the full potential of this has not been fully exploited yet. Further improvement in terms of efficiency (beyond point by point inspection) and increased sensitivity (use of focusing optics whenever the problem allows it) could easily be up to a factor of 10-20 over present instruments for many problems at a cost which is negligible compared to that of increasing the flux of the source. The real cost will be in complexity - finding the optimal set-up for a given scan and interpreting the data as the they are taken. On-line transformation of the data for an appropriate display in Q, ω space and analysis tools will be equally important for this task, and the success of these new ideas will crucially depend on how well we solve these problems. (author)

  13. Refinement of the Compton–Rayleigh scatter ratio method for use on the Mars Science Laboratory alpha particle X-ray spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, J.L., E-mail: icampbel@uoguelph.ca [Guelph-Waterloo Physics Institute, University of Guelph, Guelph, Ontario, Canada N1G 2W1 (Canada); Perrett, G.M. [Guelph-Waterloo Physics Institute, University of Guelph, Guelph, Ontario, Canada N1G 2W1 (Canada); Maxwell, J.A. [3A 47 Surrey St. East, Guelph, Ontario, Canada N1H 3P6 (Canada); Nield, E.; Gellert, R. [Guelph-Waterloo Physics Institute, University of Guelph, Guelph, Ontario, Canada N1G 2W1 (Canada); King, P.L. [Research School of Earth Sciences, Australian National University, Canberra, ACT 0200 (Australia); Lee, M.; O’Meara, J.M.; Pradler, I. [Guelph-Waterloo Physics Institute, University of Guelph, Guelph, Ontario, Canada N1G 2W1 (Canada)

    2013-05-01

    Spectra from the Mars rover alpha particle X-ray spectrometers contain the elastic and inelastic scatter peaks of the plutonium L X-rays emitted by the instrument’s {sup 244}Cm source. Various spectrum fitting approaches are tested using the terrestrial twin of the APXS instrument on the Mars Science Laboratory Curiosity rover, in order to provide accurate extraction of the Lα and Lβ Compton/Rayleigh intensity ratios, which can provide information about light “invisible” constituents such as water in geological samples. A well-defined dependence of C/R ratios upon mean sample atomic number is established using a large and varied set of geochemical reference materials, and the accuracy of this calibration is examined. Detailed attention is paid to the influence of the rubidium and strontium peaks which overlap the Lα scatter peaks. Our Monte Carlo simulation code for prediction of C/R ratios from element concentrations is updated. The ratio between measured and simulated C/R ratios provides a second means of calibration.

  14. A review on the study of polymer properties by Small Angle Neutron Scattering

    International Nuclear Information System (INIS)

    Seong, Baek Seok; Lee, Chang Hee; Sim, Hae Seop; Lee, Jung Sool; Kim, Hong Doo; Kim, Eu Gene; Cha, Kuk Heon

    1998-05-01

    This report contains concept of small angle neutron scattering , various design features and considerations of the small angle neutron spectrometer at HANARO, and recent trends of polymer studies by using this SANS technique with the installation of the spectrometer in near future. We, therefore, wish to review feasibility of small angle studies for polymer field at this spectrometer and to help possible beam time users for their experimental consideration. (author). 23 refs., 7 tabs., 23 figs

  15. A novel patch-field design using an optimized grid filter for passively scattered proton beams

    International Nuclear Information System (INIS)

    Li Yupeng; Zhang Xiaodong; Dong Lei; Mohan, Radhe

    2007-01-01

    For tumors with highly complex shapes, a 'patching' strategy is often used in passively scattered proton therapy to match the sharp distal edge of the spread-out Bragg peak (SOBP) of the patch field to the lateral penumbra of the through field at 50% dose level. The differences in the dose gradients at the distal edge and at the lateral penumbra could cause hot and cold doses at the junction. In this note, we describe an algorithm developed to optimize the range compensator design to yield a more uniform dose distribution at the junction. The algorithm is based on the fact that the distal fall-off of the SOBP can be tailored using a grid filter that is placed perpendicular to the beam's path. The filter is optimized so that the distal fall-off of the patch field complements the lateral penumbra fall-off of the through field. In addition to optimizing the fall-off, the optimization process implicitly accounts for the limitations of conventional compensator design algorithms. This algorithm uses simple ray tracing to determine the compensator shape and ignore scatter. The compensated dose distribution may therefore differ substantially from the intended dose distribution, especially when complex heterogeneities are encountered, such as those in the head and neck. In such a case, an adaptive optimization strategy can be used to optimize the 'grid' filter locally considering the tissue heterogeneities. The grid filter thus obtained is superimposed on the original range compensator so that the composite compensator leads to a more uniform dose distribution at the patch junction. An L-shaped head and neck tumor was used to demonstrate the validity of the proposed algorithm. A robustness analysis with focus on range uncertainty effect is carried out. (note)

  16. A simple, direct method for x-ray scatter estimation and correction in digital radiography and cone-beam CT

    International Nuclear Information System (INIS)

    Siewerdsen, J.H.; Daly, M.J.; Bakhtiar, B.

    2006-01-01

    X-ray scatter poses a significant limitation to image quality in cone-beam CT (CBCT), resulting in contrast reduction, image artifacts, and lack of CT number accuracy. We report the performance of a simple scatter correction method in which scatter fluence is estimated directly in each projection from pixel values near the edge of the detector behind the collimator leaves. The algorithm operates on the simple assumption that signal in the collimator shadow is attributable to x-ray scatter, and the 2D scatter fluence is estimated by interpolating between pixel values measured along the top and bottom edges of the detector behind the collimator leaves. The resulting scatter fluence estimate is subtracted from each projection to yield an estimate of the primary-only images for CBCT reconstruction. Performance was investigated in phantom experiments on an experimental CBCT benchtop, and the effect on image quality was demonstrated in patient images (head, abdomen, and pelvis sites) obtained on a preclinical system for CBCT-guided radiation therapy. The algorithm provides significant reduction in scatter artifacts without compromise in contrast-to-noise ratio (CNR). For example, in a head phantom, cupping artifact was essentially eliminated, CT number accuracy was restored to within 3%, and CNR (breast-to-water) was improved by up to 50%. Similarly in a body phantom, cupping artifact was reduced by at least a factor of 2 without loss in CNR. Patient images demonstrate significantly increased uniformity, accuracy, and contrast, with an overall improvement in image quality in all sites investigated. Qualitative evaluation illustrates that soft-tissue structures that are otherwise undetectable are clearly delineated in scatter-corrected reconstructions. Since scatter is estimated directly in each projection, the algorithm is robust with respect to system geometry, patient size and heterogeneity, patient motion, etc. Operating without prior information, analytical modeling

  17. Optimizing cone beam CT scatter estimation in egs-cbct for a clinical and virtual chest phantom

    International Nuclear Information System (INIS)

    Thing, Rune Slot; Mainegra-Hing, Ernesto

    2014-01-01

    Purpose: Cone beam computed tomography (CBCT) image quality suffers from contamination from scattered photons in the projection images. Monte Carlo simulations are a powerful tool to investigate the properties of scattered photons.egs-cbct, a recent EGSnrc user code, provides the ability of performing fast scatter calculations in CBCT projection images. This paper investigates how optimization of user inputs can provide the most efficient scatter calculations. Methods: Two simulation geometries with two different x-ray sources were simulated, while the user input parameters for the efficiency improving techniques (EITs) implemented inegs-cbct were varied. Simulation efficiencies were compared to analog simulations performed without using any EITs. Resulting scatter distributions were confirmed unbiased against the analog simulations. Results: The optimal EIT parameter selection depends on the simulation geometry and x-ray source. Forced detection improved the scatter calculation efficiency by 80%. Delta transport improved calculation efficiency by a further 34%, while particle splitting combined with Russian roulette improved the efficiency by a factor of 45 or more. Combining these variance reduction techniques with a built-in denoising algorithm, efficiency improvements of 4 orders of magnitude were achieved. Conclusions: Using the built-in EITs inegs-cbct can improve scatter calculation efficiencies by more than 4 orders of magnitude. To achieve this, the user must optimize the input parameters to the specific simulation geometry. Realizing the full potential of the denoising algorithm requires keeping the statistical uncertainty below a threshold value above which the efficiency drops exponentially

  18. Scattered image artifacts from cone beam computed tomography and its clinical potential in bone mineral density estimation.

    Science.gov (United States)

    Ko, Hoon; Jeong, Kwanmoon; Lee, Chang-Hoon; Jun, Hong Young; Jeong, Changwon; Lee, Myeung Su; Nam, Yunyoung; Yoon, Kwon-Ha; Lee, Jinseok

    2016-01-01

    Image artifacts affect the quality of medical images and may obscure anatomic structure and pathology. Numerous methods for suppression and correction of scattered image artifacts have been suggested in the past three decades. In this paper, we assessed the feasibility of use of information on scattered artifacts for estimation of bone mineral density (BMD) without dual-energy X-ray absorptiometry (DXA) or quantitative computed tomographic imaging (QCT). To investigate the relationship between scattered image artifacts and BMD, we first used a forearm phantom and cone-beam computed tomography. In the phantom, we considered two regions of interest-bone-equivalent solid material containing 50 mg HA per cm(-3) and water-to represent low- and high-density trabecular bone, respectively. We compared the scattered image artifacts in the high-density material with those in the low-density material. The technique was then applied to osteoporosis patients and healthy subjects to assess its feasibility for BMD estimation. The high-density material produced a greater number of scattered image artifacts than the low-density material. Moreover, the radius and ulna of healthy subjects produced a greater number of scattered image artifacts than those from osteoporosis patients. Although other parameters, such as bone thickness and X-ray incidence, should be considered, our technique facilitated BMD estimation directly without DXA or QCT. We believe that BMD estimation based on assessment of scattered image artifacts may benefit the prevention, early treatment and management of osteoporosis.

  19. A Ge(Li)-NaI(Tl) Compton-suppression spectrometer for in-beam γ-ray spectroscopy, ch. 2

    International Nuclear Information System (INIS)

    Driel, M.A. van; Hoogenboom, A.M.

    1976-01-01

    A Compton-suppression spectrometer has been constructed for in-beam γ-ray work. It consists of a closed-end Ge(Li) detector with an efficiency of 21% and a resolution of 2.0 keV for 1.33 MeV γ-rays surrounded by a NaI(Tl) shield (dia. 230 mm, length 280 mm). The overall Compton-suppression factor for a 60 Co spectrum is 10. Details of the construction are discussed and experimental properties are compared with design calculations

  20. An EPID response calculation algorithm using spatial beam characteristics of primary, head scattered and MLC transmitted radiation

    International Nuclear Information System (INIS)

    Rosca, Florin; Zygmanski, Piotr

    2008-01-01

    We have developed an independent algorithm for the prediction of electronic portal imaging device (EPID) response. The algorithm uses a set of images [open beam, closed multileaf collimator (MLC), various fence and modified sweeping gap patterns] to separately characterize the primary and head-scatter contributions to EPID response. It also characterizes the relevant dosimetric properties of the MLC: Transmission, dosimetric gap, MLC scatter [P. Zygmansky et al., J. Appl. Clin. Med. Phys. 8(4) (2007)], inter-leaf leakage, and tongue and groove [F. Lorenz et al., Phys. Med. Biol. 52, 5985-5999 (2007)]. The primary radiation is modeled with a single Gaussian distribution defined at the target position, while the head-scatter radiation is modeled with a triple Gaussian distribution defined downstream of the target. The distances between the target and the head-scatter source, jaws, and MLC are model parameters. The scatter associated with the EPID is implicit in the model. Open beam images are predicted to within 1% of the maximum value across the image. Other MLC test patterns and intensity-modulated radiation therapy fluences are predicted to within 1.5% of the maximum value. The presented method was applied to the Varian aS500 EPID but is designed to work with any planar detector with sufficient spatial resolution

  1. Limiting cases of the small-angle scattering approximation solutions for the propagation of laser beams in anisotropic scattering media

    Science.gov (United States)

    Box, M. A.; Deepak, A.

    1981-01-01

    The propagation of photons in a medium with strongly anisotropic scattering is a problem with a considerable history. Like the propagation of electrons in metal foils, it may be solved in the small-angle scattering approximation by the use of Fourier-transform techniques. In certain limiting cases, one may even obtain analytic expressions. This paper presents some of these results in a model-independent form and also illustrates them by the use of four different phase-function models. Sample calculations are provided for comparison purposes

  2. Effect of Beam Scanning on Target Polarization Scattering Matrix Observed by Fully Polarimetric Phased-array Radar

    Directory of Open Access Journals (Sweden)

    Li Mianquan

    2016-04-01

    Full Text Available The polarization feature of a fully Polarimetric Phased-Array Radar (PPAR antenna varies according to the beam-scanning angle, thereby introducing two problems on the target Polarization Scattering Matrix (PSM measurement. First, the antenna polarization basis is defined within the vertical cross-section of an electromagnetic wave propagation direction, and the polarization basis of each beam direction angle is not identical, resulting in the PSM of a fixed-posture target observed by PPAR being not identical for different beam-scanning angles. Second, the cross polarization of the PPAR antenna increases with increasing beamscanning angle, resulting in a crosstalk among the elements of PSM observed by PPAR. This study focuses on the analysis of the abovementioned two aspects of the effect of beam scanning on target PSM observed by PPAR. The results will establish a more accurate observation of the equation for the precision PSM measurement of PPAR.

  3. Measurement of the SMC muon beam polarisation using the asymmetry in the elastic scattering off polarised electrons

    CERN Document Server

    Adams, D; Adeva, B; Akdogan, T; Arik, E; Arvidson, A; Badelek, B; Bardin, G; Baum, G; Berglund, P; Betev, L; Birsa, R; Björkholm, P; Bonner, B E; De Botton, N R; Boutemeur, M; Bradamante, Franco; Bravar, A; Bressan, A; Bültmann, S; Burtin, E; Cavata, C; Clocchiatti, M; Crabb, D; Cranshaw, J; Çuhadar-Dönszelmann, T; Dalla Torre, S; Van Dantzig, R; Derro, B R; Deshpande, A A; Dhawan, S K; Dulya, C M; Dyring, A; Eichblatt, S; Faivre, Jean-Claude; Fasching, D; Feinstein, F; Fernández, C; Forthmann, S; Frois, Bernard; Gallas, A; Garzón, J A; Gatignon, L; Gaussiran, T; Gilly, H; Giorgi, M A; von Goeler, E; Görtz, S; Golutvin, I A; Gracia, G; De Groot, N; Grosse-Perdekamp, M; Haft, K; Von Harrach, D; Hasegawa, T; Hautle, P; Hayashi, N; Heusch, C A; Horikawa, N; Hughes, V W; Igo, G; Ishimoto, S; Iwata, T; Kabuss, E M; Kageya, T; Karev, A G; Kessler, H J; Ketel, T; Kiryluk, J; Kiryushin, Yu T; Kishi, A; Kiselev, Yu F; Klostermann, L; Krämer, Dietrich; Krivokhizhin, V G; Kröger, W; Kukhtin, V V; Kurek, K; Kyynäräinen, J; Lamanna, M; Landgraf, U; Le Goff, J M; Lehár, F; de Lesquen, A; Lichtenstadt, J; Lindqvist, T; Litmaath, M; Loewe, M; Magnon, A; Mallot, G K; Marie, F; Martin, A; Martino, J; Matsuda, T; Mayes, B W; McCarthy, J S; Medved, K S; Meyer, W T; Van Middelkoop, G; Miller, D; Miyachi, Y; Mori, K; Moromisato, J H; Nagaitsev, A P; Nassalski, J P; Naumann, Lutz; Niinikoski, T O; Oberski, J; Ogawa, A; Ozben, C; Pereira, H; Perrot-Kunne, F; Peshekhonov, V D; Piegaia, R; Pinsky, L; Platchkov, S K; Pló, M; Pose, D; Postma, H; Pretz, J; Pussieux, T; Rädel, G; Rijllart, A; Reicherz, G; Roberts, J B; Rock, S E; Rodríguez, M; Rondio, Ewa; Ropelewski, Leszek; Sabo, I; Saborido, J; Sandacz, A; Savin, I A; Schiavon, R P; Schiller, A; Schüler, K P; Seitz, R; Semertzidis, Y K; Sergeev, S; Shanahan, P; Sichtermann, E P; Simeoni, F; Smirnov, G I; Staude, A; Steinmetz, A; Stiegler, U; Stuhrmann, H B; Szleper, M; Tessarotto, F; Thers, D; Tlaczala, W; Tripet, A; Ünel, G; Velasco, M; Vogt, J; Voss, Rüdiger; Whitten, C; Windmolders, R; Willumeit, R; Wislicki, W; Witzmann, A; Ylöstalo, J; Zanetti, A M; Zaremba, K; Zamiatin, N I; Zhao, J

    2000-01-01

    A muon beam polarimeter was built for the SMC experiment at the CERN SPS, for beam energies of 100 and 190 GeV. The beam polarisation is determined from the asymmetry in the elastic scattering off the polarised electrons of a ferromagnetic target whose magnetisation is periodically reversed. At muon energies of 100 and 190~GeV the measured polarisation is $P_{\\mu}=-0.80 \\pm 0.03 (stat.)\\pm 0.02 (syst.)$ and $P_{\\mu}=-0.797 \\pm 0.011 (stat.)\\pm 0.012 (syst.)$, respectively. These results agree with measurements of the beam polarisation using a shape analysis of the decay positron energy spectrum.

  4. Inclusive Deep Inelastic Scattering at High Q2 with Longitudinally Polarised Lepton Beams at HERA

    CERN Document Server

    Aaron, F.D.; Andreev, V.; Backovic, S.; Baghdasaryan, A.; Baghdasaryan, S.; Barrelet, E.; Bartel, W.; Begzsuren, K.; Belousov, A.; Belov, P.; Bizot, J.C.; Boudry, V.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Britzger, D.; Bruncko, D.; Bunyatyan, A.; Bylinkin, A.; Bystritskaya, L.; Campbell, A.J.; Cantun Avila, K.B.; Ceccopieri, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Contreras, J.G.; Coughlan, J.A.; Cvach, J.; Dainton, J.B.; Daum, K.; Delcourt, B.; Delvax, J.; De Wolf, E.A.; Diaconu, C.; Dobre, M.; Dodonov, V.; Dossanov, A.; Dubak, A.; Eckerlin, G.; Egli, S.; Eliseev, A.; Elsen, E.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Fischer, D.J.; Fleischer, M.; Fomenko, A.; Gabathuler, E.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Goerlich, L.; Gogitidze, N.; Gouzevitch, M.; Grab, C.; Grebenyuk, A.; Greenshaw, T.; Grindhammer, G.; Habib, S.; Haidt, D.; Henderson, R.C.W.; Hennekemper, E.; Henschel, H.; Herbst, M.; Herrera, G.; Hildebrandt, M.; Hiller, K.H.; Hladky, J.; Hoffmann, D.; Horisberger, R.; Hreus, T.; Huber, F.; Jacquet, M.; Janssen, X.; Jonsson, L.; Jung, H.; Kapichine, M.; Kenyon, I.R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Kogler, R.; Kostka, P.; Kramer, M.; Kretzschmar, J.; Kruger, K.; Landon, M.P.J.; Lange, W.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Lendermann, V.; Levonian, S.; Li, G.; Lipka, K.; List, B.; List, J.; Lobodzinski, B.; Lopez-Fernandez, R.; Lubimov, V.; Malinovski, E.; Martyn, H.U.; Maxfield, S.J.; Mehta, A.; Meyer, A.B.; Meyer, H.; Meyer, J.; Mikocki, S.; Milcewicz-Mika, I.; Moreau, F.; Morozov, A.; Morris, J.V.; Muller, K.; Naumann, Th.; Newman, P.R.; Niebuhr, C.; Nikiforov, A.; Nikitin, D.; Nowak, G.; Nowak, K.; Olsson, J.E.; Ozerov, D.; Pahl, P.; Palichik, V.; Pandurovic, M.; Pascaud, C.; Patel, G.D.; Perez, E.; Petrukhin, A.; Picuric, I.; Pirumov, H.; Pitzl, D.; Placakyte, R.; Pokorny, B.; Polifka, R.; Povh, B.; Radescu, V.; Raicevic, N.; Ravdandorj, T.; Reimer, P.; Rizvi, E.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Rotaru, M.; Ruiz Tabasco, J.E.; Rusakov, S.; Salek, D.; Sankey, D.P.C.; Sauter, M.; Sauvan, E.; Schmitt, S.; Schoeffel, L.; Schoning, A.; Schultz-Coulon, H.C.; Sefkow, F.; Shtarkov, L.N.; Shushkevich, S.; Sloan, T.; Soloviev, Y.; Sopicki, P.; South, D.; Spaskov, V.; Specka, A.; Staykova, Z.; Steder, M.; Stella, B.; Stoicea, G.; Straumann, U.; Sykora, T.; Thompson, P.D.; Tran, T.H.; Traynor, D.; Truol, P.; Tsakov, I.; Tseepeldorj, B.; Turnau, J.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vazdik, Y.; Wegener, D.; Wunsch, E.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zlebcik, R.; Zohrabyan, H.; Zomer, F.

    2012-01-01

    Inclusive e\\pmp single and double differential cross sections for neutral and charged current deep inelastic scattering processes are measured with the H1 detector at HERA. The data were taken at a centre-of-mass energy of \\surds = 319GeV with a total integrated luminosity of 333.7 pb-1 shared between two lepton beam charges and two longitudinal lepton polarisation modes. The differential cross sections are measured in the range of negative fourmomentum transfer squared, Q2, between 60 and 50 000GeV2, and Bjorken x between 0.0008 and 0.65. The measurements are combined with earlier published unpolarised H1 data to improve statistical precision and used to determine the structure function xF_3^gammaZ. A measurement of the neutral current parity violating structure function F_2^gammaZ is presented for the first time. The polarisation dependence of the charged current total cross section is also measured. The new measurements are well described by a next-to-leading order QCD fit based on all published H1 inclusi...

  5. High resolution spectrometry: how the analyzer and spectrometer performances and the beam emittance contribute to the results obtained

    International Nuclear Information System (INIS)

    Roussel, P.

    1984-01-01

    Using first order calculations derived for an achromatic system A) (deltaxsub(F)/deltaEsub(i)=0) or an optimised system O) (xsub(F) minima). It is shown that the final resolution measured in the local plane of the spectrometer depends only on the emittance of the accelerator and of the efficient area of the analyser exclusive of the properties of the spectrometer. The use of this result is only limited by higher order terms in the calculation or considerations out of this scope like target effects etc.. [fr

  6. Study of {lambda} hyperon production in C+C collisions at 2 AGeV beam energy with the HADES spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Kanaki, K.

    2007-03-15

    The HADES spectrometer is a high resolution detector installed at the SIS/GSI, Darmstadt. It was primarily designed for studying dielectron decay channels of vector mesons. However, its high accuracy capabilities make it an attractive tool for investigating other rare probes at these beam energies, like strange baryons. Development and investigation of Multiwire Drift Chambers for high spatial resolution have been provided. One of the early experimental runs of HADES was analyzed and the {lambda} hyperon signal was successfully reconstructed for the first time in C+C collisions at 2 AGeV beam kinetic energy. The total {lambda} production cross section is contrasted with expectations from simulations and compared with measurements of the {lambda} yield in heavier systems at the same energy. In addition, the result is considered in the context of strangeness balance and the relative strangeness content of the reaction products is determined. (orig.)

  7. Study of Λ hyperon production in C+C collisions at 2 AGeV beam energy with the HADES spectrometer

    International Nuclear Information System (INIS)

    Kanaki, K.

    2007-03-01

    The HADES spectrometer is a high resolution detector installed at the SIS/GSI, Darmstadt. It was primarily designed for studying dielectron decay channels of vector mesons. However, its high accuracy capabilities make it an attractive tool for investigating other rare probes at these beam energies, like strange baryons. Development and investigation of Multiwire Drift Chambers for high spatial resolution have been provided. One of the early experimental runs of HADES was analyzed and the Λ hyperon signal was successfully reconstructed for the first time in C+C collisions at 2 AGeV beam kinetic energy. The total Λ production cross section is contrasted with expectations from simulations and compared with measurements of the Λ yield in heavier systems at the same energy. In addition, the result is considered in the context of strangeness balance and the relative strangeness content of the reaction products is determined. (orig.)

  8. New design for a time-of-flight mass spectrometer with a liquid beam laser desorption ion source for the analysis of biomolecules

    International Nuclear Information System (INIS)

    Charvat, A.; Lugovoj, E.; Faubel, M.; Abel, B.

    2004-01-01

    We describe a novel liquid beam mass spectrometer, based on a recently discovered nanosecond laser desorption phenomenon, [W. Kleinekofort, J. Avdiev, and B. Brutschy, Int. J. Mass Ion. Processes 152, 135 (1996)] which allows the liquid-to-vacuum transfer, and subsequent mass analysis of pre-existing ions and ionic associates from liquid microjets of aqueous solutions. The goal of our novel technical approach is to establish a system with good mass resolution that implements improvements on critical components that make the system more reliable and easier to operate. For laser desorption pulsed dye-laser difference frequency mixing is used that provides tunable infrared light near the absorption maximum of liquid water around 3 μm. Different types of liquid beam glass nozzles (convergent capillary and aperture plate nozzles) are investigated and characterized. Starting from theoretical considerations of hydrodynamic drag forces on micrometer size droplets in supersonic rarefied gas flows we succeeded in capturing efficiently the liquid beam in a liquid beam recycling trap operating at the vapor pressure of liquid water. For improving the pollution resistance, the liquid jet high vacuum ion source region is spatially separated from the reflectron time-of-flight mass spectrometer (TOF-MS) working behind a gate valve in an ultrahigh vacuum environment. A simple (simulation optimized) ion optics is employed for the ion transfer from the source to the high vacuum region. This new feature is also mostly responsible for the improved mass resolution. With the present tandem-TOF-MS setup a resolution of m/Δm≅1800 for the low and m/Δm≅700 in the high mass region has been obtained for several biomolecules of different mass and complexity (amino acids, insulin, and cytochrome c)

  9. TH-A-18C-04: Ultrafast Cone-Beam CT Scatter Correction with GPU-Based Monte Carlo Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Y [UT Southwestern Medical Center, Dallas, TX (United States); Southern Medical University, Guangzhou (China); Bai, T [UT Southwestern Medical Center, Dallas, TX (United States); Xi' an Jiaotong University, Xi' an (China); Yan, H; Ouyang, L; Wang, J; Pompos, A; Jiang, S; Jia, X [UT Southwestern Medical Center, Dallas, TX (United States); Zhou, L [Southern Medical University, Guangzhou (China)

    2014-06-15

    Purpose: Scatter artifacts severely degrade image quality of cone-beam CT (CBCT). We present an ultrafast scatter correction framework by using GPU-based Monte Carlo (MC) simulation and prior patient CT image, aiming at automatically finish the whole process including both scatter correction and reconstructions within 30 seconds. Methods: The method consists of six steps: 1) FDK reconstruction using raw projection data; 2) Rigid Registration of planning CT to the FDK results; 3) MC scatter calculation at sparse view angles using the planning CT; 4) Interpolation of the calculated scatter signals to other angles; 5) Removal of scatter from the raw projections; 6) FDK reconstruction using the scatter-corrected projections. In addition to using GPU to accelerate MC photon simulations, we also use a small number of photons and a down-sampled CT image in simulation to further reduce computation time. A novel denoising algorithm is used to eliminate MC scatter noise caused by low photon numbers. The method is validated on head-and-neck cases with simulated and clinical data. Results: We have studied impacts of photo histories, volume down sampling factors on the accuracy of scatter estimation. The Fourier analysis was conducted to show that scatter images calculated at 31 angles are sufficient to restore those at all angles with <0.1% error. For the simulated case with a resolution of 512×512×100, we simulated 10M photons per angle. The total computation time is 23.77 seconds on a Nvidia GTX Titan GPU. The scatter-induced shading/cupping artifacts are substantially reduced, and the average HU error of a region-of-interest is reduced from 75.9 to 19.0 HU. Similar results were found for a real patient case. Conclusion: A practical ultrafast MC-based CBCT scatter correction scheme is developed. The whole process of scatter correction and reconstruction is accomplished within 30 seconds. This study is supported in part by NIH (1R01CA154747-01), The Core Technology Research

  10. Optimizing a neutron-beam focusing device for the direct geometry time-of-flight spectrometer TOFTOF at the FRM II reactor source

    Energy Technology Data Exchange (ETDEWEB)

    Rasmussen, N.G. [Nanoscience Center, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø (Denmark); Simeoni, G.G., E-mail: ggsimeoni@outlook.com [Heinz Maier-Leibnitz Zentrum (MLZ) and Physics Department, Technical University of Munich, D-85748 Garching (Germany); Lefmann, K. [Nanoscience Center, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø (Denmark)

    2016-04-21

    A dedicated beam-focusing device has been designed for the direct geometry thermal-cold neutron time-of-flight spectrometer TOFTOF at the neutron facility FRM II (Garching, Germany). The prototype, based on the compressed Archimedes' mirror concept, benefits from the adaptive-optics technology (adjustable supermirror curvature) and the compact size (only 0.5 m long). We have simulated the neutron transport across the entire guide system. We present a detailed computer characterization of the existing device, along with the study of the factors mostly influencing the future improvement. We have optimized the simulated prototype as a function of the neutron wavelength, accounting also for all relevant features of a real instrument like the non-reflecting side edges. The results confirm the “chromatic” displacement of the focal point (flux density maximum) at fixed supermirror curvature, and the ability of a variable curvature to keep the focal point at the sample position. Our simulations are in excellent agreement with theoretical predictions and the experimentally measured beam profile. With respect to the possibility of a further upgrade, we find that supermirror coatings with m-values higher than 3.5 would have only marginal influence on the optimal behaviour, whereas comparable spectrometers could take advantage of longer focusing segments, with particular impact for the thermal region of the neutron spectrum.

  11. Study of the possibility to use dp-elastic scattering for the Nuclotron external deuteron beam polarimetry

    International Nuclear Information System (INIS)

    Gurchin, Yu.V.; Isupov, A.Yu.; Khrenov, A.N.; Kiselev, A.S.; Ladygin, V.P.; Reznikov, S.G.; Vasil'ev, T.A.; Janek, M.; Karachuk, J.T.

    2011-01-01

    A selection of dp-elastic scattering events at energies of 1.6 and 2.0 GeV by using scintillation counters has been performed. The procedure of the CH 2 -C subtraction has been established. The dependence of the elastic events yield on the filter thickness has been investigated. This method can be used to develop the efficient high-energy deuteron beam polarimetry

  12. Design and Simulation of a Spin Rotator for Longitudinal Field Measurements in the Low Energy Muons Spectrometer

    Science.gov (United States)

    Salman, Z.; Prokscha, T.; Keller, P.; Morenzoni, E.; Saadaoui, H.; Sedlak, K.; Shiroka, T.; Sidorov, S.; Suter, A.; Vrankovic, V.; Weber, H.-P.

    We usedGeant4 to accurately model the low energy muons (LEM) beam line, including scattering due to the 10-nm thin carbon foil in the trigger detector. Simulations of the beam line transmission give excellent agreement with experimental results for beam energies higher than ∼ 12keV.We use these simulations to design and model the operation of a spin rotator for the LEM spectrometer, which will enable longitudinal field measurements in the near future.

  13. Asymmetry measurements in p--p scattering with polarized beams and targets up to 12 GeV/c

    International Nuclear Information System (INIS)

    Auer, I.P.; Colton, E.; Halpern, H.; Hill, D.; Spinka, H.; Tamura, N.; Theodosiou, G.; Underwood, D.; Wanger, R.; Watanabe, Y.; Yokosawa, A.

    1978-01-01

    The processes of proton--proton scattering for various spin directions was investigated in the beam momentum range of 1 to 12 GeV/c. A striking energy dependence was observed at p/sub lab/ = 1 to 4 GeV/c, especially in Δ sigma/sub L/, the total cross section difference in the longitudinal spin states. The rapid energy dependence has been interpreted as evidence for the formation of diproton resonances. Various pp scattering parameters were measured at 6 GeV/c, including 3-spin parameters, which are sufficient to determine pp elastic scattering amplitudes in a model independent way at 0.2 2 . Measurements of spin--spin correlation parameters were extended to higher t and higher energies, revealing the importance of the spin dependent interaction. These measurements may shed light on the nature of the constituents and their interactions. 24 references

  14. SU-F-J-211: Scatter Correction for Clinical Cone-Beam CT System Using An Optimized Stationary Beam Blocker with a Single Scan

    Energy Technology Data Exchange (ETDEWEB)

    Liang, X; Zhang, Z; Xie, Y [Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, GuangDong (China); Gong, S; Niu, T [Department of Radiation Oncology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang (China); Institute of Translational Medicine, Zhejiang University, Hangzhou, Zhejiang (China); Zhou, Q [Department of Radiation Oncology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang (China)

    2016-06-15

    Purpose: X-ray scatter photons result in significant image quality degradation of cone-beam CT (CBCT). Measurement based algorithms using beam blocker directly acquire the scatter samples and achieve significant improvement on the quality of CBCT image. Within existing algorithms, single-scan and stationary beam blocker proposed previously is promising due to its simplicity and practicability. Although demonstrated effectively on tabletop system, the blocker fails to estimate the scatter distribution on clinical CBCT system mainly due to the gantry wobble. In addition, the uniform distributed blocker strips in our previous design results in primary data loss in the CBCT system and leads to the image artifacts due to data insufficiency. Methods: We investigate the motion behavior of the beam blocker in each projection and design an optimized non-uniform blocker strip distribution which accounts for the data insufficiency issue. An accurate scatter estimation is then achieved from the wobble modeling. Blocker wobble curve is estimated using threshold-based segmentation algorithms in each projection. In the blocker design optimization, the quality of final image is quantified using the number of the primary data loss voxels and the mesh adaptive direct search algorithm is applied to minimize the objective function. Scatter-corrected CT images are obtained using the optimized blocker. Results: The proposed method is evaluated using Catphan@504 phantom and a head patient. On the Catphan©504, our approach reduces the average CT number error from 115 Hounsfield unit (HU) to 11 HU in the selected regions of interest, and improves the image contrast by a factor of 1.45 in the high-contrast regions. On the head patient, the CT number error is reduced from 97 HU to 6 HU in the soft tissue region and image spatial non-uniformity is decreased from 27% to 5% after correction. Conclusion: The proposed optimized blocker design is practical and attractive for CBCT guided radiation

  15. SU-F-J-211: Scatter Correction for Clinical Cone-Beam CT System Using An Optimized Stationary Beam Blocker with a Single Scan

    International Nuclear Information System (INIS)

    Liang, X; Zhang, Z; Xie, Y; Gong, S; Niu, T; Zhou, Q

    2016-01-01

    Purpose: X-ray scatter photons result in significant image quality degradation of cone-beam CT (CBCT). Measurement based algorithms using beam blocker directly acquire the scatter samples and achieve significant improvement on the quality of CBCT image. Within existing algorithms, single-scan and stationary beam blocker proposed previously is promising due to its simplicity and practicability. Although demonstrated effectively on tabletop system, the blocker fails to estimate the scatter distribution on clinical CBCT system mainly due to the gantry wobble. In addition, the uniform distributed blocker strips in our previous design results in primary data loss in the CBCT system and leads to the image artifacts due to data insufficiency. Methods: We investigate the motion behavior of the beam blocker in each projection and design an optimized non-uniform blocker strip distribution which accounts for the data insufficiency issue. An accurate scatter estimation is then achieved from the wobble modeling. Blocker wobble curve is estimated using threshold-based segmentation algorithms in each projection. In the blocker design optimization, the quality of final image is quantified using the number of the primary data loss voxels and the mesh adaptive direct search algorithm is applied to minimize the objective function. Scatter-corrected CT images are obtained using the optimized blocker. Results: The proposed method is evaluated using Catphan@504 phantom and a head patient. On the Catphan©504, our approach reduces the average CT number error from 115 Hounsfield unit (HU) to 11 HU in the selected regions of interest, and improves the image contrast by a factor of 1.45 in the high-contrast regions. On the head patient, the CT number error is reduced from 97 HU to 6 HU in the soft tissue region and image spatial non-uniformity is decreased from 27% to 5% after correction. Conclusion: The proposed optimized blocker design is practical and attractive for CBCT guided radiation

  16. Monte Carlo simulation for scanning technique with scattering foil free electron beam: A proof of concept study.

    Directory of Open Access Journals (Sweden)

    Wonmo Sung

    Full Text Available This study investigated the potential of a newly proposed scattering foil free (SFF electron beam scanning technique for the treatment of skin cancer on the irregular patient surfaces using Monte Carlo (MC simulation. After benchmarking of the MC simulations, we removed the scattering foil to generate SFF electron beams. Cylindrical and spherical phantoms with 1 cm boluses were generated and the target volume was defined from the surface to 5 mm depth. The SFF scanning technique with 6 MeV electrons was simulated using those phantoms. For comparison, volumetric modulated arc therapy (VMAT plans were also generated with two full arcs and 6 MV photon beams. When the scanning resolution resulted in a larger separation between beams than the field size, the plan qualities were worsened. In the cylindrical phantom with a radius of 10 cm, the conformity indices, homogeneity indices and body mean doses of the SFF plans (scanning resolution = 1° vs. VMAT plans were 1.04 vs. 1.54, 1.10 vs. 1.12 and 5 Gy vs. 14 Gy, respectively. Those of the spherical phantom were 1.04 vs. 1.83, 1.08 vs. 1.09 and 7 Gy vs. 26 Gy, respectively. The proposed SFF plans showed superior dose distributions compared to the VMAT plans.

  17. Monte Carlo simulation for scanning technique with scattering foil free electron beam: A proof of concept study.

    Science.gov (United States)

    Sung, Wonmo; Park, Jong In; Kim, Jung-In; Carlson, Joel; Ye, Sung-Joon; Park, Jong Min

    2017-01-01

    This study investigated the potential of a newly proposed scattering foil free (SFF) electron beam scanning technique for the treatment of skin cancer on the irregular patient surfaces using Monte Carlo (MC) simulation. After benchmarking of the MC simulations, we removed the scattering foil to generate SFF electron beams. Cylindrical and spherical phantoms with 1 cm boluses were generated and the target volume was defined from the surface to 5 mm depth. The SFF scanning technique with 6 MeV electrons was simulated using those phantoms. For comparison, volumetric modulated arc therapy (VMAT) plans were also generated with two full arcs and 6 MV photon beams. When the scanning resolution resulted in a larger separation between beams than the field size, the plan qualities were worsened. In the cylindrical phantom with a radius of 10 cm, the conformity indices, homogeneity indices and body mean doses of the SFF plans (scanning resolution = 1°) vs. VMAT plans were 1.04 vs. 1.54, 1.10 vs. 1.12 and 5 Gy vs. 14 Gy, respectively. Those of the spherical phantom were 1.04 vs. 1.83, 1.08 vs. 1.09 and 7 Gy vs. 26 Gy, respectively. The proposed SFF plans showed superior dose distributions compared to the VMAT plans.

  18. Particulate contamination spectrometer. Volume 1: Technical report

    Science.gov (United States)

    Schmitt, R. J.; Boyd, B. A.; Linford, R. M. F.

    1975-01-01

    A laser particulate spectrometer (LPS) system was developed to measure the size and speed distributions of particulate (dusts, aerosols, ice particles, etc.) contaminants. Detection of the particulates was achieved by means of light scattering and extinction effects using a single laser beam to cover a size range of 0.8 to 275 microns diameter and a speed range of 0.2 to 20 meter/second. The LPS system was designed to operate in the high vacuum environment of a space simulation chamber with cold shroud temperatures ranging from 77 to 300 K.

  19. Spherical grating spectrometers

    Science.gov (United States)

    O'Donoghue, Darragh; Clemens, J. Christopher

    2014-07-01

    We describe designs for spectrometers employing convex dispersers. The Offner spectrometer was the first such instrument; it has almost exclusively been employed on satellite platforms, and has had little impact on ground-based instruments. We have learned how to fabricate curved Volume Phase Holographic (VPH) gratings and, in contrast to the planar gratings of traditional spectrometers, describe how such devices can be used in optical/infrared spectrometers designed specifically for curved diffraction gratings. Volume Phase Holographic gratings are highly efficient compared to conventional surface relief gratings; they have become the disperser of choice in optical / NIR spectrometers. The advantage of spectrometers with curved VPH dispersers is the very small number of optical elements used (the simplest comprising a grating and a spherical mirror), as well as illumination of mirrors off axis, resulting in greater efficiency and reduction in size. We describe a "Half Offner" spectrometer, an even simpler version of the Offner spectrometer. We present an entirely novel design, the Spherical Transmission Grating Spectrometer (STGS), and discuss exemplary applications, including a design for a double-beam spectrometer without any requirement for a dichroic. This paradigm change in spectrometer design offers an alternative to all-refractive astronomical spectrometer designs, using expensive, fragile lens elements fabricated from CaF2 or even more exotic materials. The unobscured mirror layout avoids a major drawback of the previous generation of catadioptric spectrometer designs. We describe laboratory measurements of the efficiency and image quality of a curved VPH grating in a STGS design, demonstrating, simultaneously, efficiency comparable to planar VPH gratings along with good image quality. The stage is now set for construction of a prototype instrument with impressive performance.

  20. A 3% Measurement of the Beam Normal Single Spin Asymmetry in Forward Angle Elastic Electron-Proton Scattering using the Qweak Setup

    Energy Technology Data Exchange (ETDEWEB)

    Waidyawansa, Dinayadura Buddhini [Ohio Univ., Athens, OH (United States)

    2013-08-01

    The beam normal single spin asymmetry generated in the scattering of transversely polarized electrons from unpolarized nucleons is an observable of the imaginary part of the two-photon exchange process. Moreover, it is a potential source of false asymmetry in parity violating electron scattering experiments. The Q{sub weak} experiment uses parity violating electron scattering to make a direct measurement of the weak charge of the proton. The targeted 4% measurement of the weak charge of the proton probes for parity violating new physics beyond the Standard Model. The beam normal single spin asymmetry at Q{sub weak} kinematics is at least three orders of magnitude larger than 5 ppb precision of the parity violating asymmetry. To better understand this parity conserving background, the Q{sub weak} Collaboration has performed elastic scattering measurements with fully transversely polarized electron beam on the proton and aluminum. This dissertation presents the analysis of the 3% measurement (1.3% statistical and 2.6% systematic) of beam normal single spin asymmetry in electronproton scattering at a Q2 of 0.025 (GeV/c)2. It is the most precise existing measurement of beam normal single spin asymmetry available at the time. A measurement of this precision helps to improve the theoretical models on beam normal single spin asymmetry and thereby our understanding of the doubly virtual Compton scattering process.

  1. Beam-helicity and beam-charge asymmetries associated with deeply virtual Compton scattering on the unpolarised proton

    Energy Technology Data Exchange (ETDEWEB)

    Airapetian, A. [Giessen Univ. (Germany). Physikalisches Inst.; Michigan Univ., Ann Arbor, MI (United States). Randall Laboratory of Physics; Akopov, N. [Yerevan Physics Institute (Armenia); Akopov, Z. [DESY Hamburg (DE)] (and others)

    2012-03-15

    Beam-helicity and beam-charge asymmetries in the hard exclusive leptoproduction of real photons from an unpolarised hydrogen target by a 27.6 GeV lepton beam are extracted from the HERMES data set of 2006-2007 using a missing-mass event selection technique. The asymmetry amplitudes extracted from this data set are more precise than those extracted from the earlier data set of 1996-2005 previously analysed in the same manner by HERMES. The results from the two data sets are compatible with each other. Results from these combined data sets are extracted and constitute the most precise asymmetry amplitude measurements made in the HERMES kinematic region using a missing-mass event selection technique. (orig.)

  2. Angle-resolving time-of-flight electron spectrometer for near-threshold precision measurements of differential cross sections of electron-impact excitation of atoms and molecules

    International Nuclear Information System (INIS)

    Lange, M.; Matsumoto, J.; Setiawan, A.; Panajotovic, R.; Harrison, J.; Lower, J. C. A.; Newman, D. S.; Mondal, S.; Buckman, S. J.

    2008-01-01

    This article presents a new type of low-energy crossed-beam electron spectrometer for measuring angular differential cross sections of electron-impact excitation of atomic and molecular targets. Designed for investigations at energies close to excitation thresholds, the spectrometer combines a pulsed electron beam with the time-of-flight technique to distinguish between scattering channels. A large-area, position-sensitive detector is used to offset the low average scattering rate resulting from the pulsing duty cycle, without sacrificing angular resolution. A total energy resolution better than 150 meV (full width at half maximum) at scattered energies of 0.5-3 eV is achieved by monochromating the electron beam prior to pulsing it. The results of a precision measurement of the differential cross section for electron-impact excitation of helium, at an energy of 22 eV, are used to assess the sensitivity and resolution of the spectrometer

  3. WE-DE-207B-12: Scatter Correction for Dedicated Cone Beam Breast CT Based On a Forward Projection Model

    Energy Technology Data Exchange (ETDEWEB)

    Shi, L; Zhu, L [Georgia Institute of Technology, Atlanta, GA (Georgia); Vedantham, S; Karellas, A [University of Massachusetts Medical School, Worcester, MA (United States)

    2016-06-15

    Purpose: The image quality of dedicated cone-beam breast CT (CBBCT) is fundamentally limited by substantial x-ray scatter contamination, resulting in cupping artifacts and contrast-loss in reconstructed images. Such effects obscure the visibility of soft-tissue lesions and calcifications, which hinders breast cancer detection and diagnosis. In this work, we propose to suppress x-ray scatter in CBBCT images using a deterministic forward projection model. Method: We first use the 1st-pass FDK-reconstructed CBBCT images to segment fibroglandular and adipose tissue. Attenuation coefficients are assigned to the two tissues based on the x-ray spectrum used for imaging acquisition, and is forward projected to simulate scatter-free primary projections. We estimate the scatter by subtracting the simulated primary projection from the measured projection, and then the resultant scatter map is further refined by a Fourier-domain fitting algorithm after discarding untrusted scatter information. The final scatter estimate is subtracted from the measured projection for effective scatter correction. In our implementation, the proposed scatter correction takes 0.5 seconds for each projection. The method was evaluated using the overall image spatial non-uniformity (SNU) metric and the contrast-to-noise ratio (CNR) with 5 clinical datasets of BI-RADS 4/5 subjects. Results: For the 5 clinical datasets, our method reduced the SNU from 7.79% to 1.68% in coronal view and from 6.71% to 3.20% in sagittal view. The average CNR is improved by a factor of 1.38 in coronal view and 1.26 in sagittal view. Conclusion: The proposed scatter correction approach requires no additional scans or prior images and uses a deterministic model for efficient calculation. Evaluation with clinical datasets demonstrates the feasibility and stability of the method. These features are attractive for clinical CBBCT and make our method distinct from other approaches. Supported partly by NIH R21EB019597, R21CA134128

  4. A novel spectrometer for studying exotic nuclei with the electron/ion collider ELISe

    International Nuclear Information System (INIS)

    Berg, G.P.A.; Adachi, T.; Harakeh, M.N.; Kalantar-Nayestanaki, N.; Woertche, H.J.; Simon, H.; Koop, I.A.; Couder, M.; Fujiwara, M.

    2011-01-01

    A novel concept of an electron spectrometer developed for the ELISe facility is presented. This spectrometer will be constructed as a part of the international Facility for Antiprotons and Ion Research (FAIR) at GSI Helmholtzzentrum fuer Schwerionenforschung. The spectrometer is designed to analyze electron scattering at the ion-electron interaction region of the NESR and EAR colliding storage rings with a high resolution and a large solid angle. A pre-deflector with a zero-field central channel along the path of the intersecting beam allows the measurement of scattered electrons without interfering with the circulating beams. Ion-optical and magnet design calculations are presented to demonstrate the feasibility and achievement of realistic design specifications.

  5. Mass- and energy-analysis of fast ion beams in PF-1000 by means of a Thomson spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Czaus, K.; Skladnik-Sadowska, E.; Malinowski, K.; Kwiatkowski, R.; Zebrowski, J. [The Andrzej Soltan Institute for Nuclear Studies - IPJ, 05-400 Otwock-Swierk (Poland); Sadowski, M.J. [The Andrzej Soltan Institute for Nuclear Studies - IPJ, 05-400 Otwock-Swierk (Poland)] [Institute of Plasma Physics and Laser Microfusion - IPPLM, 01-497 Warsaw (Poland); Zebrowski, J.; Karpinski, L.; Paduch, M.; Scholz, M.; Zielinska, E. [Institute of Plasma Physics and Laser Microfusion - IPPLM, 01-497 Warsaw (Poland); Garkusha, I.E. [Institute of Plasma Physics, NSC KIPT, 61-108 Kharkov (Ukraine)

    2011-07-01

    The paper describes measurements of energy spectra of ions emitted along the z-axis of the PF-1000 facility, which have been for the first time performed by means a miniature Thomson spectrometer during 480-kJ discharges with the deuterium filling. The recorded Thomson parabolas showed that the escaping deuterons have energies in the range of 25-1000 keV, while protons (originated from hydrogen remnants) have the population of about 2 orders smaller and energies within the range of 35-300 keV. This document is composed of a paper followed by a poster. (authors)

  6. Multichannel Thomson scattering apparatus

    International Nuclear Information System (INIS)

    Bretz, N.; Dimock, D.; Foote, V.; Johnson, D.; Long, D.; Tolnas, E.

    1977-07-01

    A Thomson scattering apparatus for measuring the electron temperature and density along a 90 cm diameter of the PLT plasma has been built. A wide angle objective images the 3 mm x 900 mm ruby laser beam onto an image dissector which rearranges the 300 : 1 image to 20 : 1 forming the input slit of a spectrometer. The stigmatic spectrometer provides 20 wavelength elements of approximately 70 A each. A micro-channel-plate image intensifier optically coupled to a cooled SIT tube provides detection with single frame linearity and 1000 : 1 dynamic range. Spatial profiles of N/sub e/ and T/sub e/ in the range 10 13 - 10 14 cm -3 and 0.05 - 3 keV have an accuracy of 30 √10 13 /N/sub e/ (cm -3 ) percent per 1.2 cm element

  7. Polarized electron beams elastically scattered by atoms as a tool for testing fundamental predictions of quantum mechanics.

    Science.gov (United States)

    Dapor, Maurizio

    2018-03-29

    Quantum information theory deals with quantum noise in order to protect physical quantum bits (qubits) from its effects. A single electron is an emblematic example of a qubit, and today it is possible to experimentally produce polarized ensembles of electrons. In this paper, the theory of the polarization of electron beams elastically scattered by atoms is briefly summarized. Then the POLARe program suite, a set of computer programs aimed at the calculation of the spin-polarization parameters of electron beams elastically interacting with atomic targets, is described. Selected results of the program concerning Ar, Kr, and Xe atoms are presented together with the comparison with experimental data about the Sherman function for low kinetic energy of the incident electrons (1.5eV-350eV). It is demonstrated that the quantum-relativistic theory of the polarization of electron beams elastically scattered by atoms is in good agreement with experimental data down to energies smaller than a few eV.

  8. The SAGE spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Pakarinen, J.; Papadakis, P. [University of Liverpool, Department of Physics, Oliver Lodge Laboratory, Liverpool (United Kingdom); University of Jyvaeskylae, Department of Physics, Jyvaeskylae (Finland); Sorri, J.; Greenlees, P.T.; Jones, P.; Julin, R.; Konki, J.; Rahkila, P.; Sandzelius, M. [University of Jyvaeskylae, Department of Physics, Jyvaeskylae (Finland); Herzberg, R.D.; Butler, P.A.; Cox, D.M.; Cresswell, J.R.; Mistry, A.; Page, R.D.; Parr, E.; Sampson, J.; Seddon, D.A.; Thornhill, J.; Wells, D. [University of Liverpool, Department of Physics, Oliver Lodge Laboratory, Liverpool (United Kingdom); Coleman-Smith, P.J.; Lazarus, I.H.; Letts, S.C.; Pucknell, V.F.E.; Simpson, J. [STFC Daresbury Laboratory, Warrington (United Kingdom)

    2014-03-15

    The SAGE spectrometer has been constructed for in-beam nuclear structure studies. SAGE combines a Ge-detector array and an electron spectrometer for detection of γ-rays and internal conversion electrons, respectively, and allows simultaneous observation of both electrons and γ-rays emitted from excited nuclei. SAGE is set up in the Accelerator Laboratory of the University of Jyvaeskylae and works in conjunction with the RITU gas-filled recoil separator and the GREAT focal-plane spectrometer allowing the use of the recoil-decay tagging method. (orig.)

  9. The SAGE spectrometer

    International Nuclear Information System (INIS)

    Pakarinen, J.; Papadakis, P.; Sorri, J.; Greenlees, P.T.; Jones, P.; Julin, R.; Konki, J.; Rahkila, P.; Sandzelius, M.; Herzberg, R.D.; Butler, P.A.; Cox, D.M.; Cresswell, J.R.; Mistry, A.; Page, R.D.; Parr, E.; Sampson, J.; Seddon, D.A.; Thornhill, J.; Wells, D.; Coleman-Smith, P.J.; Lazarus, I.H.; Letts, S.C.; Pucknell, V.F.E.; Simpson, J.

    2014-01-01

    The SAGE spectrometer has been constructed for in-beam nuclear structure studies. SAGE combines a Ge-detector array and an electron spectrometer for detection of γ-rays and internal conversion electrons, respectively, and allows simultaneous observation of both electrons and γ-rays emitted from excited nuclei. SAGE is set up in the Accelerator Laboratory of the University of Jyvaeskylae and works in conjunction with the RITU gas-filled recoil separator and the GREAT focal-plane spectrometer allowing the use of the recoil-decay tagging method. (orig.)

  10. Neutron scattering. Experiment manuals

    Energy Technology Data Exchange (ETDEWEB)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner (eds.)

    2010-07-01

    The following topics are dealt with: The thermal triple axis spectrometer PUMA, the high-resolution powder diffractometer SPODI, the hot single-crystal diffractometer HEiDi for structure analysis with neutrons, the backscattering spectrometer SPHERES, neutron polarization analysis with tht time-of-flight spectrometer DNS, the neutron spin-echo spectrometer J-NSE, small-angle neutron scattering with the KWS-1 and KWS-2 diffractometers, the very-small-angle neutron scattering diffractrometer with focusing mirror KWS-3, the resonance spin-echo spectrometer RESEDA, the reflectometer TREFF, the time-of-flight spectrometer TOFTOF. (HSI)

  11. Neutron scattering. Experiment manuals

    International Nuclear Information System (INIS)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner

    2010-01-01

    The following topics are dealt with: The thermal triple axis spectrometer PUMA, the high-resolution powder diffractometer SPODI, the hot single-crystal diffractometer HEiDi for structure analysis with neutrons, the backscattering spectrometer SPHERES, neutron polarization analysis with tht time-of-flight spectrometer DNS, the neutron spin-echo spectrometer J-NSE, small-angle neutron scattering with the KWS-1 and KWS-2 diffractometers, the very-small-angle neutron scattering diffractrometer with focusing mirror KWS-3, the resonance spin-echo spectrometer RESEDA, the reflectometer TREFF, the time-of-flight spectrometer TOFTOF. (HSI)

  12. Scattering and extinction of ion beams in a dusty plasma device

    International Nuclear Information System (INIS)

    Nakamura, Y.

    2001-01-01

    Collisions of ions with charged dust grains are important for the propagation of low frequency waves such as dust acoustic waves and dust ion-acoustic waves. The collision cross-sectional area of charged dust grains depends on the velocity of an ion beam. The collision cross-sectional area of charged dust grains with beam ions is measured. It is compared with the geometrical cross-sectional area of the grain. The experiment is performed in a dusty double-plasma device with glass beads of 8.9 μm in average diameter. The ion beam current and energy are measured with a directional retarding potential analyzer. It is observed that, when dust density inside the system is increased, the beam current ratio is reduced. From the reduction of the ion beam current, the effective cross-sectional area of the dust particle is estimated as a function of the beam energy

  13. Self-modulation and anomalous collective scattering of laser produced intense ion beam in plasmas

    Directory of Open Access Journals (Sweden)

    K. Mima

    2018-05-01

    Full Text Available The collective interaction between intense ion beams and plasmas is studied by simulations and experiments, where an intense proton beam produced by a short pulse laser is injected into a pre-ionized gas. It is found that, depending on its current density, collective effects can significantly alter the propagated ion beam and the stopping power. The quantitative agreement that is found between theories and experiments constitutes the first validation of the collective interaction theory. The effects in the interaction between intense ion beams and background gas plasmas are of importance for the design of laser fusion reactors as well as for beam physics. Keywords: Two stream instabilities, Ultra intense short pulse laser, Proton beam, Wake field, Electron plasma wave, Laser plasma interaction, PACS codes: 52.38.Kd, 29.27.Fh, 52.40.Kh, 52.70.Nc

  14. Laser Plasma Instability (LPI) Driven Light Scattering Measurements with 44 beam-lines of Nike KrF Laser^*

    Science.gov (United States)

    Oh, J.; Weaver, J. L.; Kehne, D. M.; Phillips, L. S.; Obenschain, S. P.; Serlin, V.; McLean, E. A.; Lehmberg, R. H.; Manka, C. K.

    2009-11-01

    With short wavelength (248 nm), large bandwidth (˜1 THz), and ISI beam smoothing, Nike KrF laser provides unique opportunities of LPI research for direct-drive inertial confinement fusion. Previous experiments at intensities (10^15˜10^16 W/cm^2) exceeded two-plasmon decay (TPD) instability threshold using 12 beam-lines of Nike laser.^a,b For further experiments to study LPI excitation in bigger plasma volumes, 44 Nike main beams have been used to produce plasmas with total laser energies up to 1 kJ of ˜350 psec FWHM pulses. This talk will present results of the recent LPI experiment focusing on light emission data in spectral ranges relevant to the Raman (SRS) and TPD instabilities. The primary diagnostics were time-resolved spectrometers with an absolute-intensity-calibrated photodiode array in (0.4˜0.8)φ0 and a streak camera near 0.5φ0. Blackbody temperature and expansion speed measurements of the plasmas were also made. The experiment was conducted at laser intensities of (1˜4)x10^15 W/cm^2 on solid planar CH targets. ^a J. L. Weaver, et al, NO4.14, APS DPP (2008) ^b J. Oh, et al, NO4.15, APS DPP (2008) * Work supported by DoE/NNSA and performed at Naval Research Laboratory.

  15. Mechanical neutron spectrometer Chopper - Experimental study of the neutron beam topography in the channel C of the 'A' reactor; Neutronski mehanicki spektrometar (coper) - Eksperimentalno odredjivanje topografije neutronskog snopa na kanalu 'C', reaktora 'A'

    Energy Technology Data Exchange (ETDEWEB)

    Markovic, V [Institute of Nuclear Sciences Boris Kidric, Laboratorija za reaktorsku i neutronsku fiziku, Vinca, Beograd (Serbia and Montenegro)

    1961-12-15

    The objective of the experiment was to measure the axis of the neutron beam from the reactor channel. The collimator, mechanical spectrometer and detectors are to be placed along this axis. Two points along the channel are determined to be defined as centres of the neutron beam. During this experiments the collimators were placed in the reactor at distance of 100 cm and cross section of 3.5 cm in diameter. BF{sub 3} detectors were used for the experiment.

  16. Development of a golden beam data set for the commissioning of a proton double-scattering system in a pencil-beam dose calculation algorithm

    International Nuclear Information System (INIS)

    Slopsema, R. L.; Flampouri, S.; Yeung, D.; Li, Z.; Lin, L.; McDonough, J. E.; Palta, J.

    2014-01-01

    Purpose: The purpose of this investigation is to determine if a single set of beam data, described by a minimal set of equations and fitting variables, can be used to commission different installations of a proton double-scattering system in a commercial pencil-beam dose calculation algorithm. Methods: The beam model parameters required to commission the pencil-beam dose calculation algorithm (virtual and effective SAD, effective source size, and pristine-peak energy spread) are determined for a commercial double-scattering system. These parameters are measured in a first room and parameterized as function of proton energy and nozzle settings by fitting four analytical equations to the measured data. The combination of these equations and fitting values constitutes the golden beam data (GBD). To determine the variation in dose delivery between installations, the same dosimetric properties are measured in two additional rooms at the same facility, as well as in a single room at another facility. The difference between the room-specific measurements and the GBD is evaluated against tolerances that guarantee the 3D dose distribution in each of the rooms matches the GBD-based dose distribution within clinically reasonable limits. The pencil-beam treatment-planning algorithm is commissioned with the GBD. The three-dimensional dose distribution in water is evaluated in the four treatment rooms and compared to the treatment-planning calculated dose distribution. Results: The virtual and effective SAD measurements fall between 226 and 257 cm. The effective source size varies between 2.4 and 6.2 cm for the large-field options, and 1.0 and 2.0 cm for the small-field options. The pristine-peak energy spread decreases from 1.05% at the lowest range to 0.6% at the highest. The virtual SAD as well as the effective source size can be accurately described by a linear relationship as function of the inverse of the residual energy. An additional linear correction term as function of

  17. Development of a golden beam data set for the commissioning of a proton double-scattering system in a pencil-beam dose calculation algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Slopsema, R. L., E-mail: rslopsema@floridaproton.org; Flampouri, S.; Yeung, D.; Li, Z. [University of Florida Proton Therapy Institute, 2015 North Jefferson Street, Jacksonville, Florida 32205 (United States); Lin, L.; McDonough, J. E. [Department of Radiation Oncology, University of Pennsylvania, 3400 Civic Boulevard, 2326W TRC, PCAM, Philadelphia, Pennsylvania 19104 (United States); Palta, J. [VCU Massey Cancer Center, Virginia Commonwealth University, 401 College Street, Richmond, Virginia 23298 (United States)

    2014-09-15

    Purpose: The purpose of this investigation is to determine if a single set of beam data, described by a minimal set of equations and fitting variables, can be used to commission different installations of a proton double-scattering system in a commercial pencil-beam dose calculation algorithm. Methods: The beam model parameters required to commission the pencil-beam dose calculation algorithm (virtual and effective SAD, effective source size, and pristine-peak energy spread) are determined for a commercial double-scattering system. These parameters are measured in a first room and parameterized as function of proton energy and nozzle settings by fitting four analytical equations to the measured data. The combination of these equations and fitting values constitutes the golden beam data (GBD). To determine the variation in dose delivery between installations, the same dosimetric properties are measured in two additional rooms at the same facility, as well as in a single room at another facility. The difference between the room-specific measurements and the GBD is evaluated against tolerances that guarantee the 3D dose distribution in each of the rooms matches the GBD-based dose distribution within clinically reasonable limits. The pencil-beam treatment-planning algorithm is commissioned with the GBD. The three-dimensional dose distribution in water is evaluated in the four treatment rooms and compared to the treatment-planning calculated dose distribution. Results: The virtual and effective SAD measurements fall between 226 and 257 cm. The effective source size varies between 2.4 and 6.2 cm for the large-field options, and 1.0 and 2.0 cm for the small-field options. The pristine-peak energy spread decreases from 1.05% at the lowest range to 0.6% at the highest. The virtual SAD as well as the effective source size can be accurately described by a linear relationship as function of the inverse of the residual energy. An additional linear correction term as function of

  18. Steel research using neutron beam techniques. In-situ neutron diffraction, small-angle neutron scattering and residual stress analysis

    International Nuclear Information System (INIS)

    Sueyoshi, Hitoshi; Ishikawa, Nobuyuki; Yamada, Katsumi; Sato, Kaoru; Nakagaito, Tatsuya; Matsuda, Hiroshi; Arakaki, Yu; Tomota, Yo

    2014-01-01

    Recently, the neutron beam techniques have been applied for steel researches and industrial applications. In particular, the neutron diffraction is a powerful non-destructive method that can analyze phase transformation and residual stress inside the steel. The small-angle neutron scattering is also an effective method for the quantitative evaluation of microstructures inside the steel. In this study, in-situ neutron diffraction measurements during tensile test and heat treatment were conducted in order to investigate the deformation and transformation behaviors of TRIP steels. The small-angle neutron scattering measurements of TRIP steels were also conducted. Then, the neutron diffraction analysis was conducted on the high strength steel weld joint in order to investigate the effect of the residual stress distribution on the weld cracking. (author)

  19. A Fourier transform spectrometer without a beam splitter for the vacuum ultraviolet range: From the optical design to the first UV spectrum.

    Science.gov (United States)

    de Oliveira, N; Joyeux, D; Phalippou, D; Rodier, J C; Polack, F; Vervloet, M; Nahon, L

    2009-04-01

    We describe a Fourier transform (FT) spectrometer designed to operate down to 60 nm (20 eV) on a synchrotron radiation beamline for high resolution absorption spectrometry. As far as we know, such an instrument is not available below 140 nm mainly because manufacturing accurate and efficient beam splitters remains a major problem at these wavelengths, especially if a wide bandwidth operation is desired. In order to overcome this difficulty, we developed an interferometer based on wave front division instead of amplitude division. It relies on a modified Fresnel bimirror configuration that requires only flat mirrors. The instrument provides path difference scanning through the translation of one reflector. During the scanning, the moving reflector is controlled by an optical system that keeps its direction constant within a tolerable value and provides an accurate interferometric measurement of the path difference variation. Therefore, a regular interferogram sampling is obtained, producing a nominal spectral impulse response and an accurate spectral calibration. The first results presented in this paper show a measured spectral resolution of delta(sigma)=0.33 cm-1 (interval between spectral samples). This was obtained with a sampling interval of 29 nm (path difference) and 512 K samples from a one-sided interferogram using a cosine FT. Such a sampling interval should allow the recording of large bandwidth spectra down to lambda=58 nm with an ultimate resolving power of 500,000 at this wavelength. In order to check the instrument performances, we first recorded an interferogram from a He-Ne stabilized laser. This provided the actual spectral impulse function, which was found to be fully satisfactory. The determination of the impulse response distortion and of the noise on the vacuum ultraviolet (VUV) spectral range provided accurate information in the sampling error profile over a typical scan. Finally, the instrument has been moved to the SU5 undulator

  20. Quantitative analysis of artifacts in 4D DSA: the relative contributions of beam hardening and scatter to vessel dropout behind highly attenuating structures

    Science.gov (United States)

    Hermus, James; Szczykutowicz, Timothy P.; Strother, Charles M.; Mistretta, Charles

    2014-03-01

    When performing Computed Tomographic (CT) image reconstruction on digital subtraction angiography (DSA) projections, loss of vessel contrast has been observed behind highly attenuating anatomy, such as dental implants and large contrast filled aneurysms. Because this typically occurs only in a limited range of projection angles, the observed contrast time course can potentially be altered. In this work, we have developed a model for acquiring DSA projections that models both the polychromatic nature of the x-ray spectrum and the x-ray scattering interactions to investigate this problem. In our simulation framework, scatter and beam hardening contributions to vessel dropout can be analyzed separately. We constructed digital phantoms with large clearly defined regions containing iodine contrast, bone, soft issue, titanium (dental implants) or combinations of these materials. As the regions containing the materials were large and rectangular, when the phantoms were forward projected, the projections contained uniform regions of interest (ROI) and enabled accurate vessel dropout analysis. Two phantom models were used, one to model the case of a vessel behind a large contrast filled aneurysm and the other to model a vessel behind a dental implant. Cases in which both beam hardening and scatter were turned off, only scatter was turned on, only beam hardening was turned on, and both scatter and beam hardening were turned on, were simulated for both phantom models. The analysis of this data showed that the contrast degradation is primarily due to scatter. When analyzing the aneurysm case, 90.25% of the vessel contrast was lost in the polychromatic scatter image, however only 50.5% of the vessel contrast was lost in the beam hardening only image. When analyzing the teeth case, 44.2% of the vessel contrast was lost in the polychromatic scatter image and only 26.2% of the vessel contrast was lost in the beam hardening only image.

  1. Stimulated Brillouin scattering reflectivity in the case of a spatially smoothed laser beam interacting with an inhomogeneous plasma

    International Nuclear Information System (INIS)

    Tikhonchuk, V.T.; Mounaix, P.; Pesme, D.

    1997-01-01

    The stimulated Brillouin scattering (SBS) instability is investigated theoretically in the case of a spatially smoothed laser beam interacting with an inhomogeneous plasma in the regime of strong ion acoustic damping. The domain of parameters being considered corresponds to most of the present day experiments carried out with nanosecond laser pulses interacting with preformed plasmas: the characteristic length for convective amplification is assumed to be much shorter than the longitudinal correlation length of the laser field. The SBS reflectivity of one individual hot spot is analytically computed taking into account thermal noise emission and pump depletion within the hot spot. The SBS reflectivity of the whole beam is then obtained by summing up the individual hot spot reflectivities in accordance with their statistical distribution. copyright 1997 American Institute of Physics

  2. Proposal to perform a high - statisics neutrino scattering experiment using a fine - grained detector in the NuMI Beam

    Energy Technology Data Exchange (ETDEWEB)

    Morfin, J.G.; /Fermilab; McFarland, K.; /Rochester U.

    2003-12-01

    The NuMI facility at Fermilab will provide an extremely intense beam of neutrinos for the MINOS neutrino-oscillation experiment. The spacious and fully-outfitted MINOS near detector hall will be the ideal venue for a high-statistics, high-resolution {nu} and {bar {nu}}-nucleon/nucleus scattering experiment. The experiment described here will measure neutrino cross-sections and probe nuclear effects essential to present and future neutrino-oscillation experiments. Moreover, with the high NuMI beam intensity, the experiment will either initially address or significantly improve our knowledge of a wide variety of neutrino physics topics of interest and importance to the elementary-particle and nuclear-physics communities.

  3. Measurement of charged current deep inelastic scattering cross sections with a longitudinally polarised electron beam at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2008-12-01

    Measurements of the cross sections for charged current deep inelastic scattering in e - p collisions with longitudinally polarised electron beams are presented. The measurements are based on a data sample with an integrated luminosity of 175 pb -1 collected with the ZEUS detector at HERA at a centre-of-mass energy of 318 GeV. The total cross section is given for positively and negatively polarised electron beams. The differential cross-sections dσ/dQ 2 , dσ/dx and dσ/dy are presented for Q 2 >200 GeV 2 . The double-differential cross-section d 2 σ/dxdQ 2 is presented in the kinematic range 280 2 and 0.015< x<0.65. The measured cross sections are compared with the predictions of the Standard Model. (orig.)

  4. Construction of a scattering chamber for ion-beam analysis of environmental materials in undergraduate physics research

    Energy Technology Data Exchange (ETDEWEB)

    LaBrake, Scott M.; Vineyard, Michael F.; Turley, Colin F.; Moore, Robert D.; Johnson, Christopher [Department of Physics and Astronomy Union College, Schenectady, NY 12308 (United States)

    2013-04-19

    We have developed a new scattering chamber for ion-beam analysis of environmental materials with the 1.1-MV Pelletron accelerator at the Union College Ion-Beam Analysis Laboratory. The chamber was constructed from a ten-inch, Conflat, multi-port cross and includes a three-axis target manipulator and target ladder assembly, an eight-inch turbo pump, an Amptek X-ray detector, and multiple charged particle detectors. Recent projects performed by our undergraduate research team include proton induced X-ray emission (PIXE) and Rutherford backscattering (RBS) analyses of atmospheric aerosols collected with a nine-stage cascade impactor in Upstate New York. We will describe the construction of the chamber and discuss the results of some commissioning experiments.

  5. Influence of incoherent scattering on stochastic deflection of high-energy negative particle beams in bent crystals

    Energy Technology Data Exchange (ETDEWEB)

    Kirillin, I.V. [Akhiezer Institute for Theoretical Physics, National Science Center ' ' Kharkov Institute of Physics and Technology' ' , Kharkov (Ukraine); Shul' ga, N.F. [Akhiezer Institute for Theoretical Physics, National Science Center ' ' Kharkov Institute of Physics and Technology' ' , Kharkov (Ukraine); V.N. Karazin Kharkov National University, Kharkov (Ukraine); Bandiera, L. [INFN Sezione di Ferrara, Ferrara (Italy); Guidi, V.; Mazzolari, A. [INFN Sezione di Ferrara, Ferrara (Italy); Universita degli Studi di Ferrara, Dipartimento di Fisica e Scienze della Terra, Ferrara (Italy)

    2017-02-15

    An investigation on stochastic deflection of high-energy negatively charged particles in a bent crystal was carried out. On the basis of analytical calculation and numerical simulation it was shown that there is a maximum angle at which most of the beam is deflected. The existence of a maximum, which is taken in the correspondence of the optimal radius of curvature, is a novelty with respect to the case of positively charged particles, for which the deflection angle can be freely increased by increasing the crystal length. This difference has to be ascribed to the stronger contribution of incoherent scattering affecting the dynamics of negative particles that move closer to atomic nuclei and electrons. We therefore identified the ideal parameters for the exploitation of axial confinement for negatively charged particle beam manipulation in future high-energy accelerators, e.g., ILC or muon colliders. (orig.)

  6. LANSCE '90: the Manuel Lujan Jr. Neutron Scattering Center

    International Nuclear Information System (INIS)

    Pynn, Roger

    1991-01-01

    This paper describes progress that has been made at the Manuel Lujan Jr. Neutron Scattering Center (LANSCE) during the past two years. Presently, LANSCE provides a higher peak neutron flux than any other pulsed spallation neutron source. There are seven spectrometers for neutron scattering experiments that are operated for a national user program sponsored by the U.S. Department of Energy. Two more spectrometers are under construction. Plans have been made to raise the number of beam holes available for instrumentation and to improve the efficiency of the target/moderator system. (author)

  7. LANSCE '90: The Manuel Lujan Jr. Neutron Scattering Center

    International Nuclear Information System (INIS)

    Pynn, R.

    1990-01-01

    This paper describes progress that has been made at the Manuel Lujan Jr. Neutron Scattering Center (LANSCE) during the past two years. Presently, LANSCE provides a higher peak neutron flux than any other pulsed spallation neutron source. There are seven spectrometers for neutron scattering experiments that are operated for a national user program sponsored by the US Department of Energy. Two more spectrometers are under construction. Plans have been made to raise the number of beam holes available for instrumentation and to improve the efficiency of the target/moderator system. 9 refs., 4 figs

  8. Spatial dose and microdose distribution in tissues. Ionization, nuclear reactions, multiple scattering simulation of beam transport

    International Nuclear Information System (INIS)

    Jacquot, C.

    1976-01-01

    Computer simulation and nuclear emulsion and gelatin techniques enabled to give the total elastic and inelastic cross sections and to forecast the spatial microdose distributions in cells, nuclei and molecules. For this purpose, the transport of a beam into tissues having a given composition is calculated, the nuclear reactions are generated and the energy depositions in standard planes perpendicular to the beam are recorded

  9. Scattering of thermal He beams by crossed atomic and molecular beams. II. The He--Ar van der Waals potential

    International Nuclear Information System (INIS)

    Keilb, M.; Slankas, J.T.; Kuppermann, A.

    1979-01-01

    Differential cross sections for He--Ar scattering at room temperature have been measured. The experimental consistency of these measurements with others performed in different laboratories is demonstrated. Despite this consistency, the present van der Waals well depth of 1.78 meV, accurate to 10%, is smaller by 20% to 50% than the experimental values obtained previously. These discrepancies are caused by differences between the assumed mathematical forms or between the assumed dispersion coefficients of the potentials used in the present paper and those of previous studies. Independent investigations have shown that the previous assumptions are inappropriate for providing accurate potentials from fits to experimental differential cross section data for He--Ar. We use two forms free of this inadequacy in the present analysis: a modified version of the Simons--Parr--Finlan--Dunham (SPFD) potential, and a double Morse--van der Waals (M 2 SV) type of parameterization. The resulting He--Ar potentials are shown to be equal to with experimental error, throughout the range of interatomic distances to which the scattering data are sensitive. The SPFD or M 2 SV potentials are combined with a repulsive potential previously determined exclusively from fits to gas phase bulk properties. The resulting potentials, valid over the extended range of interatomic distances r> or approx. =2.4 A, are able to reproduce all these bulk properties quite well, without adversely affecting the quality of the fits to the DCS

  10. Comparison of Head Scatter Factor for 6MV and 10MV flattened (FB) and Unflattened (FFF) Photon Beam using indigenously Designed Columnar Mini Phantom.

    Science.gov (United States)

    Ashokkumar, Sigamani; Nambi Raj, N Arunai; Sinha, Sujit Nath; Yadav, Girigesh; Thiyagarajan, Rajesh; Raman, Kothanda; Mishra, Manindra Bhushan

    2014-07-01

    To measure and compare the head scatter factor for flattened (FB) and unflattened (FFF) of 6MV and 10MV photon beam using indigenously designed mini phantom. A columnar mini phantom was designed as recommended by AAPM Task Group 74 with low and high atomic number materials at 10 cm (mini phantom) and at approximately twice the depth of maximum dose water equivalent thickness (brass build-up cap). Scatter in the accelerator (Sc) values of 6MV-FFF photon beams are lesser than that of the 6MV-FB photon beams (0.66-2.8%; Clinac iX, 2300CD) and (0.47-1.74%; True beam) for field sizes ranging from 10 × 10 cm(2) to 40 × 40 cm(2). Sc values of 10MV-FFF photon beams are lesser (0.61-2.19%; True beam) than that of the 10MV-FB photons beams for field sizes ranging from 10 × 10 cm(2) to 40 × 40 cm(2). The SSD had no influence on head scatter for both flattened and unflattened beams and irrespective of head design of the different linear accelerators. The presence of field shaping device influences the Sc values. The collimator exchange effect reveals that the opening of the upper jaw increases Sc irrespective of FB or FFF photon beams and different linear accelerators, and it is less significant in FFF beams. Sc values of 6MV-FB square field were in good agreement with that of AAPM, TG-74 published data for Varian (Clinac iX, 2300CD) accelerator. Our results confirm that the removal of flattening filter decreases in the head scatter factor compared to flattened beam. This could reduce the out-of-field dose in advanced treatment delivery techniques.

  11. pF3D Simulations of Large Outer-Beam Brillouin Scattering from NIF Rugby Hohlraums

    Science.gov (United States)

    Langer, Steven; Strozzi, David; Chapman, Thomas; Amendt, Peter

    2015-11-01

    We assess the cause of large outer-beam stimulated Brillouin scattering (SBS) in a NIF shot with a rugby-shaped hohlraum, which has less wall surface loss and thus higher x-ray drive than a cylindrical hohlraum of the same radius. This shot differed from a prior rugby shot with low SBS in three ways: outer beam pointing, split-pointing of the four beams within each outer-beam quadruplet, and a small amount of neon added to the hohlraum helium fill gas. We use pF3D, a massively-parallel, paraxial-envelope laser plasma interaction code, with plasma profiles from the radiation-hydrodynamics code Lasnex. We determine which change between the two shots increased the SBS by adding them one at a time to the simulations. We compare the simulations to experimental data for total SBS power, its spatial distribution at the lens, and the SBS spectrum. For each shot, we use profiles from Lasnex simulations with and without a model for mix at the hohlraum wall-gas interface. Work performed under the auspices of the U.S. Department of Energy by LLNL under Contract DE-AC52-07NA27344. Release number LLNL-ABS-674893.

  12. Measurement of neutron spectra generated by a 62 AMeV carbon-ion beam on a PMMA phantom using extended range Bonner sphere spectrometers

    International Nuclear Information System (INIS)

    Bedogni, R.; Amgarou, K.; Domingo, C.; Russo, S.; Cirrone, G.A.P.; Pelliccioni, M.; Esposito, A.; Pola, A.; Introini, M.V.; Gentile, A.

    2012-01-01

    Neutrons constitute an important component of the radiation environment in hadron therapy accelerators. Their energy distribution may span from thermal up to hundred of MeV. The characterization of these fields in terms of dosimetric or spectrometric quantities is crucial for either the patient protection or the facility design aspects. To date, the Extended Range Bonner Sphere Spectrometer (ERBSS) is the only instrument able to simultaneously determine all spectral components in such workplaces. With the aim of providing useful data to the scientific community involved in neutron measurements at hadron therapy facilities, a measurement campaign was carried out at the Centro di AdroTerapia e Applicazioni Nucleari Avanzate (CATANA) of INFN-LNS (Laboratori Nazionali del Sud), where a 62 AMeV carbon ion is available. The beam was directed towards a PMMA phantom, simulating the patient, and two neutron measurement points were established at 0° and 90° with respect to the beam-line. The ERBSSs of UAB (Universidad Autónoma de Barcelona-Grup de Física de les Radiacions) and INFN (Istituto Nazionale di Fisica Nucleare-Laboratori Nazionali di Frascati) were used to measure the resulting neutron fields. The two ERBSSs use different detectors and sphere diameters, and have been independently calibrated. The FRUIT code was used to unfold the results.

  13. Measurement of neutron spectra generated by a 62 AMeV carbon-ion beam on a PMMA phantom using extended range Bonner sphere spectrometers

    Energy Technology Data Exchange (ETDEWEB)

    Bedogni, R., E-mail: roberto.bedogni@lnf.infn.it [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati, Via E. Fermi 40, 00044 Frascati (Italy); Amgarou, K.; Domingo, C. [Grup de Recerca en Radiacions Ionitzants, Departament de Fisica, Universitat Autonoma de Barcelona, E-08193 Bellaterra (Spain); Russo, S.; Cirrone, G.A.P. [Istituto Nazionale di Fisica Nucleare-Laboratori Nazionali dei Sud, Via S. Sofia 62, 95125 Catania (Italy); Pelliccioni, M.; Esposito, A. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati, Via E. Fermi 40, 00044 Frascati (Italy); Pola, A.; Introini, M.V. [Politecnico di Milano, CESNEF, Dipartimento di Energia, via Ponzio 34/3, 20133 Milano (Italy); Gentile, A. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati, Via E. Fermi 40, 00044 Frascati (Italy)

    2012-07-21

    Neutrons constitute an important component of the radiation environment in hadron therapy accelerators. Their energy distribution may span from thermal up to hundred of MeV. The characterization of these fields in terms of dosimetric or spectrometric quantities is crucial for either the patient protection or the facility design aspects. To date, the Extended Range Bonner Sphere Spectrometer (ERBSS) is the only instrument able to simultaneously determine all spectral components in such workplaces. With the aim of providing useful data to the scientific community involved in neutron measurements at hadron therapy facilities, a measurement campaign was carried out at the Centro di AdroTerapia e Applicazioni Nucleari Avanzate (CATANA) of INFN-LNS (Laboratori Nazionali del Sud), where a 62 AMeV carbon ion is available. The beam was directed towards a PMMA phantom, simulating the patient, and two neutron measurement points were established at 0 Degree-Sign and 90 Degree-Sign with respect to the beam-line. The ERBSSs of UAB (Universidad Autonoma de Barcelona-Grup de Fisica de les Radiacions) and INFN (Istituto Nazionale di Fisica Nucleare-Laboratori Nazionali di Frascati) were used to measure the resulting neutron fields. The two ERBSSs use different detectors and sphere diameters, and have been independently calibrated. The FRUIT code was used to unfold the results.

  14. Measurement of neutron spectra generated by a 62 AMeV carbon-ion beam on a PMMA phantom using extended range Bonner sphere spectrometers

    Science.gov (United States)

    Bedogni, R.; Amgarou, K.; Domingo, C.; Russo, S.; Cirrone, G. A. P.; Pelliccioni, M.; Esposito, A.; Pola, A.; Introini, M. V.; Gentile, A.

    2012-07-01

    Neutrons constitute an important component of the radiation environment in hadron therapy accelerators. Their energy distribution may span from thermal up to hundred of MeV. The characterization of these fields in terms of dosimetric or spectrometric quantities is crucial for either the patient protection or the facility design aspects. To date, the Extended Range Bonner Sphere Spectrometer (ERBSS) is the only instrument able to simultaneously determine all spectral components in such workplaces. With the aim of providing useful data to the scientific community involved in neutron measurements at hadron therapy facilities, a measurement campaign was carried out at the Centro di AdroTerapia e Applicazioni Nucleari Avanzate (CATANA) of INFN-LNS (Laboratori Nazionali del Sud), where a 62 AMeV carbon ion is available. The beam was directed towards a PMMA phantom, simulating the patient, and two neutron measurement points were established at 0° and 90° with respect to the beam-line. The ERBSSs of UAB (Universidad Autónoma de Barcelona-Grup de Física de les Radiacions) and INFN (Istituto Nazionale di Fisica Nucleare-Laboratori Nazionali di Frascati) were used to measure the resulting neutron fields. The two ERBSSs use different detectors and sphere diameters, and have been independently calibrated. The FRUIT code was used to unfold the results.

  15. Dosimetry and microdosimetry using LET spectrometer based on the track-etch detector: radiotherapy bremsstrahlung beam, onboard aircraft radiation field

    Czech Academy of Sciences Publication Activity Database

    Jadrníčková, Iva; Spurný, František

    2006-01-01

    Roč. 41, č. 4 (2006), s. 421-429 ISSN 0033-8451 R&D Projects: GA ČR GA202/04/0795; GA ČR(CZ) GD202/05/H031 Institutional research plan: CEZ:AV0Z10480505 Keywords : linear energy transfer * bremsstrahlung beam * onboard aircraft Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders

  16. Quasielastic neutron scattering facility at Dhruva reactor

    International Nuclear Information System (INIS)

    Mukhopadhyay, R.; Mitra, S.; Paranjpe, S.K.; Dasannacharya, B.A.

    2001-01-01

    Quasi-elastic neutron scattering is a powerful experimental tool for studying the various dynamical motions in solids and liquids. In this paper, we have described the salient features of the quasi-elastic neutron spectrometer in operation at Dhruva reactor at Trombay, India. The design criteria have been such as to maximise the throughput by various means like closer approach to the source, focusing a larger beam on to a sample, and Multi-Angle Reflecting X-tal mode of energy analysis. Some results of molecular motions from recently studied systems using this spectrometer are also reported

  17. Monolithic spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Rajic, Slobodan (Knoxville, TN); Egert, Charles M. (Oak Ridge, TN); Kahl, William K. (Knoxville, TN); Snyder, Jr., William B. (Knoxville, TN); Evans, III, Boyd M. (Oak Ridge, TN); Marlar, Troy A. (Knoxville, TN); Cunningham, Joseph P. (Oak Ridge, TN)

    1998-01-01

    A monolithic spectrometer is disclosed for use in spectroscopy. The spectrometer is a single body of translucent material with positioned surfaces for the transmission, reflection and spectral analysis of light rays.

  18. Measurement of the neutron fields produced by a 62 MeV proton beam on a PMMA phantom using extended range Bonner sphere spectrometers

    Science.gov (United States)

    Amgarou, K.; Bedogni, R.; Domingo, C.; Esposito, A.; Gentile, A.; Carinci, G.; Russo, S.

    2011-10-01

    The experimental characterization of the neutron fields produced as parasitic effect in medical accelerators is assuming an increased importance for either the patient protection or the facility design aspects. Medical accelerators are diverse in terms of particle type (electrons or hadrons) and energy, but the radiation fields around them have in common (provided that a given threshold energy is reached) the presence of neutrons with energy span over several orders of magnitude. Due to the large variability of neutron energy, field or dosimetry measurements in these workplaces are very complex, and in general, cannot be performed with ready-to-use commercial instruments. In spite of its poor energy resolution, the Bonner Sphere Spectrometer (BSS) is the only instrument able to simultaneously determine all spectral components in such workplaces. The energy range of this instrument is limited to ECATANA) of INFN—LNS (Laboratori Nazionali del Sud), where a proton beam routinely used for ophthalmic cancer treatments is available. The 62 MeV beam was directed towards a PMMA phantom, simulating the patient, and two neutron measurement points were established at 0° and 90° with respect to the beam-line. Here the ERBSS of UAB (Universidad Autónoma de Barcelona— Grup de Física de les Radiacions) and INFN (Istituto Nazionale di Fisica Nucleare—Laboratori Nazionali di Frascati) were exposed to characterize the "forward" and "sideward" proton-induced neutron fields. The use of two ERBSS characterized by different set of spheres, central detectors, and independently established and calibrated, is important for guaranteeing the robustness of the measured spectra and estimating their overall uncertainties.

  19. Compact terahertz spectrometer based on disordered rough surfaces

    Science.gov (United States)

    Yang, Tao; Jiang, Bing; Ge, Jia-cheng; Zhu, Yong-yuan; Li, Xing-ao; Huang, Wei

    2018-01-01

    In this paper, a compact spectrometer based on disordered rough surfaces for operation in the terahertz band is presented. The proposed spectrometer consists of three components, which are used for dispersion, modulation and detection respectively. The disordered rough surfaces, which are acted as the dispersion component, are modulated by the modulation component. Different scattering intensities are captured by the detection component with different extent of modulation. With a calibration measurement process, one can reconstruct the spectra of the probe terahertz beam by solving a system of simultaneous linear equations. A Tikhonov regularization approach has been implemented to improve the accuracy of the spectral reconstruction. The reported broadband, compact, high-resolution terahertz spectrometer is well suited for portable terahertz spectroscopy applications.

  20. Application of focused-beam flat-sample method to synchrotron powder X-ray diffraction with anomalous scattering effect

    International Nuclear Information System (INIS)

    Tanaka, M; Katsuya, Y; Matsushita, Y

    2013-01-01

    The focused-beam flat-sample method (FFM), which is a method for high-resolution and rapid synchrotron X-ray powder diffraction measurements by combination of beam focusing optics, a flat shape sample and an area detector, was applied for diffraction experiments with anomalous scattering effect. The advantages of FFM for anomalous diffraction were absorption correction without approximation, rapid data collection by an area detector and good signal-to-noise ratio data by focusing optics. In the X-ray diffraction experiments of CoFe 2 O 4 and Fe 3 O 4 (By FFM) using X-rays near the Fe K absorption edge, the anomalous scattering effect between Fe/Co or Fe 2+ /Fe 3+ can be clearly detected, due to the change of diffraction intensity. The change of observed diffraction intensity as the incident X-ray energy was consistent with the calculation. The FFM is expected to be a method for anomalous powder diffraction.

  1. Deeply Virtual Compton Scattering and its Beam Charge Asymmetry in $e^{\\pm} p$ Collisions at HERA

    CERN Document Server

    Aaron, F.D.; Alexa, C.; Alimujiang, K.; Andreev, V.; Antunovic, B.; Backovic, S.; Baghdasaryan, A.; Barrelet, E.; Bartel, W.; Begzsuren, K.; Belousov, A.; Bizot, J.C.; Boudry, V.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Bruncko, D.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Cantun Avila, K.B.; Cerny, K.; Cerny, V.; Chekelian, V.; Cholewa, A.; Contreras, J.G.; Coughlan, J.A.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Daum, K.; Deak, M.; de Boer, Y.; Delcourt, B.; Del Degan, M.; Delvax, J.; De Wolf, E.A.; Diaconu, C.; Dodonov, V.; Dossanov, A.; Dubak, A.; Eckerlin, G.; Efremenko, V.; Egli, S.; Eliseev, A.; Elsen, E.; Falkiewicz, A.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Fischer, D.-J.; Fleischer, M.; Fomenko, A.; Gabathuler, E.; Gayler, J.; Ghazaryan, Samvel; Glazov, A.; Glushkov, I.; Goerlich, L.; Gogitidze, N.; Gouzevitch, M.; Grab, C.; Greenshaw, T.; Grell, B.R.; Grindhammer, G.; Habib, S.; Haidt, D.; Helebrant, C.; Henderson, R.C.W.; Hennekemper, E.; Henschel, H.; Herbst, M.; Herrera, G.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hreus, T.; Jacquet, M.; Janssen, M.E.; Janssen, X.; Jonsson, L.; Jung, Andreas Werner; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I.R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Kluge, T.; Knutsson, A.; Kogler, R.; Kostka, P.; Kraemer, M.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Kruger, K.; Kutak, K.; Landon, M.P.J.; Lange, W.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Li, G.; Lipka, K.; Liptaj, A.; List, B.; List, J.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Makankine, A.; Malinovski, E.; Marage, P.; Marti, Ll.; Martyn, H.-U.; Maxfield, S.J.; Mehta, A.; Meyer, A.B.; Meyer, H.; Meyer, H.; Meyer, J.; Michels, V.; Mikocki, S.; Milcewicz-Mika, I.; Moreau, F.; Morozov, A.; Morris, J.V.; Mozer, Matthias Ulrich; Mudrinic, M.; Muller, K.; Murin, P.; Naumann, Th.; Newman, P.R.; Niebuhr, C.; Nikiforov, A.; Nikitin, D.; Nowak, G.; Nowak, K.; Nozicka, M.; Olivier, B.; Olsson, J.E.; Osman, S.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Pandurovic, M.; Papadopoulou, Th.; Pascaud, C.; Patel, G.D.; Pejchal, O.; Perez, E.; Petrukhin, A.; Picuric, I.; Piec, S.; Pitzl, D.; Placakyte, R.; Pokorny, B.; Polifka, R.; Povh, B.; Radescu, V.; Rahmat, A.J.; Raicevic, N.; Raspiareza, A.; Ravdandorj, T.; Reimer, P.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rotaru, M.; Ruiz Tabasco, J.E.; Rurikova, Z.; Rusakov, S.; Salek, D.; Sankey, D.P.C.; Sauter, M.; Sauvan, E.; Schmitt, S.; Schoeffel, L.; Schoning, A.; Schultz-Coulon, H.-C.; Sefkow, F.; Shaw-West, R.N.; Shtarkov, L.N.; Shushkevich, S.; Sloan, T.; Smiljanic, Ivan; Soloviev, Y.; Sopicki, P.; South, D.; Spaskov, V.; Specka, Arnd E.; Staykova, Z.; Steder, M.; Stella, B.; Stoicea, G.; Straumann, U.; Sunar, D.; Sykora, T.; Tchoulakov, V.; Thompson, G.; Thompson, P.D.; Toll, T.; Tomasz, F.; Tran, T.H.; Traynor, D.; Trinh, T.N.; Truol, P.; Tsakov, I.; Tseepeldorj, B.; Turnau, J.; Urban, K.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Vinokurova, S.; Volchinski, V.; von den Driesch, M.; Wegener, D.; Wissing, Ch.; Wunsch, E.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.; Zus, R.

    2009-01-01

    A measurement of elastic deeply virtual Compton scattering gamma* p -> gamma p using e^+ p and e^- p collision data recorded with the H1 detector at HERA is presented. The analysed data sample corresponds to an integrated luminosity of 306 pb^-1, almost equally shared between both beam charges. The cross section is measured as a function of the virtuality Q^2 of the exchanged photon and the centre-of-mass energy W of the gamma* p system in the kinematic domain 6.5 < Q^2 < 80 GeV^2, 30 < W < 140 GeV and |t| < 1 GeV^2, where t denotes the squared momentum transfer at the proton vertex. The cross section is determined differentially in t for different Q^2 and W values and exponential t-slope parameters are derived. Using e^+ p and e^- p data samples, a beam charge asymmetry is extracted for the first time in the low Bjorken x kinematic domain. The observed asymmetry is attributed to the interference between Bethe-Heitler and deeply virtual Compton scattering processes. Experimental results are dis...

  2. Exclusive compton scattering on the proton

    International Nuclear Information System (INIS)

    Chen, J.P.; Chudakov, E.; DeJager, C.; Degtyarenko, P.; Ent, R.; Gomez, J.; Hansen, O.; Keppel, C.; Klein, F.; Kuss, M.

    1999-01-01

    An experiment is proposed to measure the cross sections for Real Compton Scattering from the proton in the energy range 3-6 GeV and over a wide angular range, and to measure the longitudinal and transverse components of the polarization transfer to the recoil proton at a single kinematic point. Together, these measurements will test models of the reaction mechanism and determine new structure functions of the proton that are related to the same non-forward parton densities that determine the elastic electron scattering form factors and the parton densities. The experiment utilizes an untagged Bremsstrahlung photon beam and the standard Hall A cryogenic targets. The scattered photon is detected in a photon spectrometer, currently under construction. The coincident recoil proton is detected in one of the Hall A magnetic spectrometers and its polarization components are measured in the existing Focal Plane Polarimeter. This proposal extends and supersedes E97 - 108 which was approved by PAC13. (author)

  3. Exclusive compton scattering on the proton

    Energy Technology Data Exchange (ETDEWEB)

    Chen, J.P.; Chudakov, E.; DeJager, C.; Degtyarenko, P.; Ent, R.; Gomez, J.; Hansen, O.; Keppel, C.; Klein, F.; Kuss, M. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)] [and others

    1999-07-01

    An experiment is proposed to measure the cross sections for Real Compton Scattering from the proton in the energy range 3-6 GeV and over a wide angular range, and to measure the longitudinal and transverse components of the polarization transfer to the recoil proton at a single kinematic point. Together, these measurements will test models of the reaction mechanism and determine new structure functions of the proton that are related to the same non-forward parton densities that determine the elastic electron scattering form factors and the parton densities. The experiment utilizes an untagged Bremsstrahlung photon beam and the standard Hall A cryogenic targets. The scattered photon is detected in a photon spectrometer, currently under construction. The coincident recoil proton is detected in one of the Hall A magnetic spectrometers and its polarization components are measured in the existing Focal Plane Polarimeter. This proposal extends and supersedes E97 - 108 which was approved by PAC13. (author)

  4. Exclusive Compton Scattering on the Proton

    International Nuclear Information System (INIS)

    Chen, J. P.; Chudakov, E.; DeJager, C.; Degtyarenko, P.; Ent, R.; Gomez, J.; Hansen, O.; Keppel, C.; Klein, F.; Kuss, M.; LeRose, J.; Liang, M.; Michaels, R.; Mitchell, J.; Liyanage, N.; Rutt, P.; Saha, A.; Wojtsekhowski, B.; Bouwhuis, M.; Chang, T.H.; Holt, R. J.; Nathan, A. M.; Roedelbronn, M.; Wijesooriya, K.; Williamson, S. E.; Dodge, G.; Hyde-Wright, C.; Radyushkin, A.; Sabatie, F.; Weinstein, L. B.; Ulmer, P.; Bosted, P.; Finn, J. M.; Jones, M.; Churchwell, S.; Howell, C.; Gilman, R.; Glashausser, C.; Jiang, X.; Ransome, R.; Strauch, S.; Berthot, J.; Bertin, P.; Fonvielle, H.; Roblin, Y.; Bertozzi, W.; Gilad, S.; Rowntree, D.; Zu, Z.; Brown, D.; Chang, G.; Afanasev, A.; Egiyan, K.; Hoohauneysan, E.; Ketikyan, A.; Mailyan, S.; Petrosyan, A.; Shahinyan, A.; Voskanyan, H.; Boeglin, W.; Markowitz, P.; Hines, J.; Strobel, G.; Templon, J.; Feldman, G.; Morris, C. L.; Gladyshev, V.; Lindgren, R. A.; Calarco, J.; Hersman, W.; Leuschner, M.; Gasparian, A.

    1999-01-01

    An experiment is proposed to measure the cross sections for Real Compton Scattering from the proton in the energy range 3-6 GeV and over a wide angular range; and to measure the longitudinal and transverse components of the polarization transfer to the recoil proton at a single kinematic point. Together; these measurements will test models of the reaction mechanism and determine new structure functions of the proton that are related to the same nonforward parton densities that determine the elastic electron scattering form factors and the parton densities. The experiment utilizes an untagged bremsstrahlung photon beam and the standard Hall A cryogenic targets. The scattered photon is detected in a photon spectrometer; currently under construction. The coincident recoil proton is detected in one of the Hall A magnetic spectrometers and its polarization components are measured in the existing Focal Plane Polarimeter. This proposal extends and supercedes E97-108 which was approved by PAC13

  5. The influence of incident beam's angle offset of Fourier transform infrared spectrometer on the spectrum measurement explored with synchrotron radiation

    International Nuclear Information System (INIS)

    Chen Wenhao; Chen Min; Xiao Tiqiao

    2011-01-01

    Effects of the incident angle offset on FT-IR spectra are investigated in this paper. The simulated FT-IR spectra are obtained by Fourier inverse transform. The results show that this frequency shift varies with the angle offset of the incident beam in FT-IR. As an example,the factors that affect the angle of incident IR light at SSRF are analyzed. According to performance specifications of the IR beamline, requirements of the optical component installation precision and position drift of the light source are given. (authors)

  6. Computational study of scattering of a zero-order Bessel beam by large nonspherical homogeneous particles with the multilevel fast multipole algorithm

    Science.gov (United States)

    Yang, Minglin; Wu, Yueqian; Sheng, Xinqing; Ren, Kuan Fang

    2017-12-01

    Computation of scattering of shaped beams by large nonspherical particles is a challenge in both optics and electromagnetics domains since it concerns many research fields. In this paper, we report our new progress in the numerical computation of the scattering diagrams. Our algorithm permits to calculate the scattering of a particle of size as large as 110 wavelengths or 700 in size parameter. The particle can be transparent or absorbing of arbitrary shape, smooth or with a sharp surface, such as the Chebyshev particles or ice crystals. To illustrate the capacity of the algorithm, a zero order Bessel beam is taken as the incident beam, and the scattering of ellipsoidal particles and Chebyshev particles are taken as examples. Some special phenomena have been revealed and examined. The scattering problem is formulated with the combined tangential formulation and solved iteratively with the aid of the multilevel fast multipole algorithm, which is well parallelized with the message passing interface on the distributed memory computer platform using the hybrid partitioning strategy. The numerical predictions are compared with the results of the rigorous method for a spherical particle to validate the accuracy of the approach. The scattering diagrams of large ellipsoidal particles with various parameters are examined. The effect of aspect ratios, as well as half-cone angle of the incident zero-order Bessel beam and the off-axis distance on scattered intensity, is studied. Scattering by asymmetry Chebyshev particle with size parameter larger than 700 is also given to show the capability of the method for computing scattering by arbitrary shaped particles.

  7. Polarized triple-axis spectrometer TASP

    Energy Technology Data Exchange (ETDEWEB)

    Boeni, P; Keller, P [Lab. for Neutron Scattering ETH Zurich, Zurich (Switzerland) and Paul Scherrer Institute, Villigen (Switzerland)

    1996-11-01

    The polarized triple-axis spectrometer TASP at SINQ has been optimized for measuring magnetic cross sections in condensed matter. The neutrons are polarized or analyzed either by means of benders or Heusler monochromators. The beam divergence, i.e. the intensity, and the spectral range of the neutrons is rather large because of the supermirror coatings of the feeding neutron guide. The intensity can be further increased at the sample position by means of a focussing monochromator and a focussing anti-trumpet. The end position of TASP allows the tailoring of the neutron beam already before the monochromator and to scatter neutrons over very wide ranges of angles. (author) 6 figs., 1 tab., 8 refs.

  8. Coherent beam combination using self-phase locked stimulated Brillouin scattering phase conjugate mirrors with a rotating wedge for high power laser generation.

    Science.gov (United States)

    Park, Sangwoo; Cha, Seongwoo; Oh, Jungsuk; Lee, Hwihyeong; Ahn, Heekyung; Churn, Kil Sung; Kong, Hong Jin

    2016-04-18

    The self-phase locking of a stimulated Brillouin scattering-phase conjugate mirror (SBS-PCM) allows a simple and scalable coherent beam combination of existing lasers. We propose a simple optical system composed of a rotating wedge and a concave mirror to overcome the power limit of the SBS-PCM. Its phase locking ability and the usefulness on the beam-combination laser are demonstrated experimentally. A four-beam combination is demonstrated using this SBS-PCM scheme. The relative phases between the beams were measured to be less than λ/24.7.

  9. The Lise spectrometer at Ganil

    International Nuclear Information System (INIS)

    Saint-Laurent, M.G.

    1986-08-01

    The doubly achromatic spectrometer LISE is available at the french national heavy ion accelerator GANIL. Experimental results, obtained in radioactive beam production and search for new exotic nuclei are briefly reported

  10. In-beam test of the Boron-10 Multi-Grid neutron detector at the IN6 time-of-flight spectrometer at the ILL

    Energy Technology Data Exchange (ETDEWEB)

    Birch, J; Hultman, L; Höglund, C [Linköping University, Thin Film Physics Division, IFM, SE-581 83 Linköping (Sweden); Buffet, J-C; Clergeau, J-F; Correa, J; Van Esch, P; Ferraton, M; Guerard, B; Halbwachs, J; Khaplanov, A; Koza, M; Piscitelli, F; Zbiri, M [Institute Laue Langevin, Rue Jules Horowitz, FR-38000 Grenoble (France); Hall-Wilton, R [European Spallation Source ESS AB, P.O Box 176, SE-221 00 Lund (Sweden)

    2014-07-24

    A neutron detector concept based on solid layers of boron carbide enriched in {sup 10}B has been in development for the last few years as an alternative for {sup 3}He by collaboration between the ILL, ESS and Linköping University. This Multi-Grid detector uses layers of aluminum substrates coated with {sup 10}B{sub 4}C on both sides that are traversed by the incoming neutrons. Detection is achieved using a gas counter readout principle. By segmenting the substrate and using multiple anode wires, the detector is made inherently position sensitive. This development is aimed primarily at neutron scattering instruments with large detector areas, such as time-of-flight chopper spectrometers. The most recent prototype has been built to be interchangeable with the {sup 3}He detectors of IN6 at ILL. The {sup 10}B detector has an active area of 32 x 48cm{sup 2}. It was installed at the IN6 instrument and operated for several weeks, collecting data in parallel with the regularly scheduled experiments, thus providing the first side-by-side comparison with the conventional {sup 3}He detectors. Results include an efficiency comparison, assessment of the in-detector scattering contribution, sensitivity to gamma-rays and the signal-to-noise ratio in time-of-flight spectra. The good expected performance has been confirmed with the exception of an unexpected background count rate. This has been identified as natural alpha activity in aluminum. New convertor substrates are under study to eliminate this source of background.

  11. Neutron scattering facilities at China Institute of Atomic Energy. Present and future situations

    International Nuclear Information System (INIS)

    Ye, C.T.; Gou, C.; Yang, T.H.

    2001-01-01

    The 15 MW Heavy Water Research Reactor (HWRR) at CIAE in Beijing is the only neutron source available for neutron scattering experiments in China at present. So far totally 5 neutron scattering spectrometers are installed at 4 beam tubes. A 60 MW new research reactor, China Advanced Research Reactor (CARR), now is being built at CIAE to meet the increasing demand of neutron scattering research in China. A brief description of HWRR, the presently existing neutron scattering equipments at HWRP, CARR, and the neutron scattering facilities to be installed at CARR are presented. (J.P.N.)

  12. Theory and optical design of x-ray echo spectrometers

    Science.gov (United States)

    Shvyd'ko, Yuri

    2017-08-01

    X-ray echo spectroscopy, a space-domain counterpart of neutron spin echo, is a recently proposed inelastic x-ray scattering (IXS) technique. X-ray echo spectroscopy relies on imaging IXS spectra and does not require x-ray monochromatization. Due to this, the echo-type IXS spectrometers are broadband, and thus have a potential to simultaneously provide dramatically increased signal strength, reduced measurement times, and higher resolution compared to the traditional narrow-band scanning-type IXS spectrometers. The theory of x-ray echo spectrometers presented earlier [Yu. Shvyd'ko, Phys. Rev. Lett. 116, 080801 (2016), 10.1103/PhysRevLett.116.080801] is developed here further with a focus on questions of practical importance, which could facilitate optical design and assessment of the feasibility and performance of the echo spectrometers. Among others, the following questions are addressed: spectral resolution, refocusing condition, echo spectrometer tolerances, refocusing condition adjustment, effective beam size on the sample, spectral window of imaging and scanning range, impact of the secondary source size on the spectral resolution, angular dispersive optics, focusing and collimating optics, and detector's spatial resolution. Examples of optical designs and characteristics of echo spectrometers with 1-meV and 0.1-meV resolutions are presented.

  13. The Crossed-Beam Scattering Method in Studies of Ion-Molecule Reaction Dynamics

    Czech Academy of Sciences Publication Activity Database

    Herman, Zdeněk

    2001-01-01

    Roč. 212, - (2001), s. 413-443 ISSN 1387-3806 R&D Projects: GA ČR GA203/00/0632 Institutional research plan: CEZ:AV0Z4040901 Keywords : ion-molecule reaction dynamics * ion scattering * experimental methods Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.176, year: 2001

  14. Electron beam energy monitoring using thermoluminescent dosimeters and electron back scattering

    International Nuclear Information System (INIS)

    Nelson, Vinod; Gray, Alison

    2013-01-01

    Periodic checks of megavoltage electron beam quality are a fundamental requirement in ensuring accurate radiotherapy treatment delivery. In the present work, thermoluminescent dosimeters (TLDs) positioned on either side of a lead sheet at the surface of a water equivalent phantom were used to monitor electron beam quality using the electron backscattering method. TLD100 and TLD100H were evaluated as upstream detectors and TLD200, TLD400 and TLD500 were evaluated as downstream detectors. The evaluation assessed the test sensitivity and correlation, long and short term reproducibility, dose dependence and glow curve features. A prototype of an in-air jig suitable for use in postal TLD dose audits was also developed and an initial evaluation performed. The results indicate that the TLD100-TLD200 combination provides a sensitive and reproducible method to monitor electron beam quality. The light weight and easily fabricated in-air jig was found to produce acceptable results and has the potential to be used by radiation monitoring agencies to carry out TLD postal quality assurance audits, similar to audits presently being conducted for photon beams. -- Highlights: ► Monitoring electron beam quality via electron backscattering was investigated. ► Different thermoluminescent materials were evaluated as detectors. ► A TLD100-TLD200 combination produced the most sensitive and reproducible results. ► An in-air jig was evaluated to allow measurements via postal dose audits

  15. Measurement of the polarisation of a muon beam of 190 GeV by scattering on a target of polarised electrons

    International Nuclear Information System (INIS)

    Burtin, Etienne

    1996-01-01

    This research thesis reports the development of a muon-based polarimeter which implements elastic scattering of muons on a target of polarised electrons. In its first part, it describes the deeply inelastic scattering process, and presents the theoretical framework for the interpretation of experimental results. The author describes the experimental installation, and the measurement of the beam polarisation by elastic scattering on a target of polarised electrons. He reports the analysis of data obtained with a 190 GeV beam, the discussion and assessment of error sources, the comparison of these results with other measurements using the muon in-flight disintegration, and with the prediction obtained by the beam line simulation. He finally reports the results of the SMC experiment obtained for the proton and the deuteron, and demonstrates the verification of the Bjorken sum rule

  16. Scattering of thermal He beams by crossed atomic and molecular beams. I. Sensitivity of the elastic differential cross section to the interatomic potential

    International Nuclear Information System (INIS)

    Keil, M.; Kuppermann, A.

    1978-01-01

    The ability of diffraction oscillations in atomic beam scattering experiments to uniquely determine interatomic potentials for highly quantal systems is examined. Assumed but realistic potentials are used to generate, by scattering calculations and incorporation of random errors, differential cross sections which are then treated as if they were ''experimental'' data. From these, attempts are made to recover the initial potential by varying the parameters of assumed mathematical forms different from the original one, until a best fit to the ''experimental'' results is obtained. It is found that the region of the interaction potential around the van der Waals minimum is accurately determined by the ''measured'' differential cross sections over a range of interatomic separations significantly wider than would be expected classically. It is also found, for collision energies at which the weakly repulsive wall is appreciably sampled, that the SPF--Dunham and double Morse--van der Waals types of potentials lead to accurate determinations of the interatomic potential, whereas many other mathematical forms do not. Analytical parameterizations most appropriate for obtaining accurate interatomic potentials from thermal DCS experiments, for a given highly quantal system, may depend on the collision energy used

  17. Molecular beam studies of hot atom chemical reactions: Reactive scattering of energetic deuterium atoms

    International Nuclear Information System (INIS)

    Continetti, R.E.; Balko, B.A.; Lee, Y.T.

    1989-02-01

    A brief review of the application of the crossed molecular beams technique to the study of hot atom chemical reactions in the last twenty years is given. Specific emphasis is placed on recent advances in the use of photolytically produced energetic deuterium atoms in the study of the fundamental elementary reactions D + H 2 /minus/> DH + H and the substitution reaction D + C 2 H 2 /minus/> C 2 HD + H. Recent advances in uv laser and pulsed molecular beam techniques have made the detailed study of hydrogen atom reactions under single collision conditions possible. 18 refs., 9 figs

  18. Molecular Beam Studies of Hot Atom Chemical Reactions: Reactive Scattering of Energetic Deuterium Atoms

    Science.gov (United States)

    Continetti, R. E.; Balko, B. A.; Lee, Y. T.

    1989-02-01

    A brief review of the application of the crossed molecular beams technique to the study of hot atom chemical reactions in the last twenty years is given. Specific emphasis is placed on recent advances in the use of photolytically produced energetic deuterium atoms in the study of the fundamental elementary reactions D + H{sub 2} -> DH + H and the substitution reaction D + C{sub 2}H{sub 2} -> C{sub 2}HD + H. Recent advances in uv laser and pulsed molecular beam techniques have made the detailed study of hydrogen atom reactions under single collision conditions possible.

  19. Neutron scattering. Experiment manuals

    International Nuclear Information System (INIS)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner

    2014-01-01

    The following topics are dealt with: The thermal triple-axis spectrometer PUMA, the high-resolution powder diffractometer SPODI, the hot-single-crystal diffractometer HEiDi, the three-axis spectrometer PANDA, the backscattering spectrometer SPHERES, the DNS neutron-polarization analysis, the neutron spin-echo spectrometer J-NSE, small-angle neutron scattering at KWS-1 and KWS-2, a very-small-angle neutron scattering diffractometer with focusing mirror, the reflectometer TREFF, the time-of-flight spectrometer TOFTOF. (HSI)

  20. Helium Atom Scattering from C2H6, F2HCCH3, F3CCH2F and C2F6 in Crossed Molecular Beams

    Science.gov (United States)

    Hammer, Markus; Seidel, Wolfhart

    1997-10-01

    Rotationally unresolved differential cross sections were measured in crossed molecular beam experiments by scattering Helium atoms from Ethane, 1,1-Difluoroethane, 1,1,1,2-Tetrafluoroethane and Hexafluoroethane. The damping of observed diffraction oscillations was used to extract anisotropic interaction potentials for these scattering systems applying the infinite order sudden approximation (IOSA). Binary macroscopic parameters such as second heterogeneous virial coefficients and the coefficients of diffusion and viscosity were computed from these potentials and compared to results from macroscopic experiments.

  1. Binary moving-blocker-based scatter correction in cone-beam computed tomography with width-truncated projections: proof of concept

    Science.gov (United States)

    Lee, Ho; Fahimian, Benjamin P.; Xing, Lei

    2017-03-01

    This paper proposes a binary moving-blocker (BMB)-based technique for scatter correction in cone-beam computed tomography (CBCT). In concept, a beam blocker consisting of lead strips, mounted in front of the x-ray tube, moves rapidly in and out of the beam during a single gantry rotation. The projections are acquired in alternating phases of blocked and unblocked cone beams, where the blocked phase results in a stripe pattern in the width direction. To derive the scatter map from the blocked projections, 1D B-Spline interpolation/extrapolation is applied by using the detected information in the shaded regions. The scatter map of the unblocked projections is corrected by averaging two scatter maps that correspond to their adjacent blocked projections. The scatter-corrected projections are obtained by subtracting the corresponding scatter maps from the projection data and are utilized to generate the CBCT image by a compressed-sensing (CS)-based iterative reconstruction algorithm. Catphan504 and pelvis phantoms were used to evaluate the method’s performance. The proposed BMB-based technique provided an effective method to enhance the image quality by suppressing scatter-induced artifacts, such as ring artifacts around the bowtie area. Compared to CBCT without a blocker, the spatial nonuniformity was reduced from 9.1% to 3.1%. The root-mean-square error of the CT numbers in the regions of interest (ROIs) was reduced from 30.2 HU to 3.8 HU. In addition to high resolution, comparable to that of the benchmark image, the CS-based reconstruction also led to a better contrast-to-noise ratio in seven ROIs. The proposed technique enables complete scatter-corrected CBCT imaging with width-truncated projections and allows reducing the acquisition time to approximately half. This work may have significant implications for image-guided or adaptive radiation therapy, where CBCT is often used.

  2. Electric field measurements at near-atmospheric pressure by coherent Raman scattering of laser beams

    International Nuclear Information System (INIS)

    Ito, Tsuyohito; Kobayashi, Kazunobu; Hamaguchi, Satoshi; Mueller, Sarah; Czarnetzki, Uwe

    2010-01-01

    Electric field measurements at near-atmospheric pressure environments based on electric-field induced Raman scattering are applied to repetitively pulsed nanosecond discharges. The results have revealed that the peak electric field near the centre of the gap is almost independent of the applied voltage. Minimum sustainable voltage measurements suggests that, at each discharge pulse, charged particles that remain from the previous pulse serve as discharge seeds and play an important role for generation of uniform glow-like discharges.

  3. Scatter and leakage contributions to the out-of-field absorbed dose distribution in water phantom around the medical LINAC radiation beams

    International Nuclear Information System (INIS)

    Bordy, J.M.; Bessiere, I.; Ostrowsky, A.; Poumarede, B.; Sorel, S.; Vermesse, D.

    2013-01-01

    This work is carried out within the framework of EURADOS Working Group 9 (WG9) whose general objective is 'to assess non-target organ doses in radiotherapy and the related risks of second cancers, with the emphasis on dosimetry'. The objective of the present work is to provide reference values (i) to evaluate the current methods of deriving three-dimensional dose distributions in and around the target volume using passive dosimeters, (ii) to derive the leakage dose from the head of the medical linear accelerator (LINAC) and the doses due to scattered radiation from the collimator edges and the body (phantom) itself. Radiation qualities of 6, 12 and 20 MV are used with standard calibration conditions described in IAEA TRS 398 and nonstandard conditions at a reference facility at the Laboratoire National Henri Becquerel (CEA LIST/LNE LNHB). An ionisation chamber is used to measure profile and depth dose in especially design water phantom built to enable investigation of doses up to 60 cm from the beam axis. A first set of experiments is carried out with the beam passing through the tank. From this first experiment, penumbra and out-of-field dose profiles including water and collimator scatter and leakage are found over three orders of magnitude. Two further sets of experiments using the same experimental arrangement with the beam outside the tank, to avoid water scatter, are designed to measure collimator scatter and leakage by closing the jaws of the collimator. It is shown that the ratios between water scatter, collimator scatter and leakage depend on the photon energy. Depending on the energy, typical leakage and collimator scatter represents 10-40% and 30-50% of the total out-of-field doses respectively. Water scatter decreases with energy while leakage increases with energy, and collimator scatter varies only slowly with energy. (authors)

  4. Application of the rigorous method to x-ray and neutron beam scattering on rough surfaces

    International Nuclear Information System (INIS)

    Goray, Leonid I.

    2010-01-01

    The paper presents a comprehensive numerical analysis of x-ray and neutron scattering from finite-conducting rough surfaces which is performed in the frame of the boundary integral equation method in a rigorous formulation for high ratios of characteristic dimension to wavelength. The single integral equation obtained involves boundary integrals of the single and double layer potentials. A more general treatment of the energy conservation law applicable to absorption gratings and rough mirrors is considered. In order to compute the scattering intensity of rough surfaces using the forward electromagnetic solver, Monte Carlo simulation is employed to average the deterministic diffraction grating efficiency due to individual surfaces over an ensemble of realizations. Some rules appropriate for numerical implementation of the theory at small wavelength-to-period ratios are presented. The difference between the rigorous approach and approximations can be clearly seen in specular reflectances of Au mirrors with different roughness parameters at wavelengths where grazing incidence occurs at close to or larger than the critical angle. This difference may give rise to wrong estimates of rms roughness and correlation length if they are obtained by comparing experimental data with calculations. Besides, the rigorous approach permits taking into account any known roughness statistics and allows exact computation of diffuse scattering.

  5. On optimization of an experimental system consisting of beam guidance and nuclear detectors

    International Nuclear Information System (INIS)

    Lehr, H.; Hinderer, G.; Maier, K.H.

    1978-02-01

    This report deals with the optimization of the resolution in nuclear physics experiments with a beam of accelerated particles. The complete system consisting of the beam handling, the nuclear reaction, and the particle detection is described with a linear matrix formalism. This allows to give analytic expressions for the linewidth of any physically interesting quantities, like Q-values of scattering angle in the center of mass system, as a function of beam line-, nuclear reaction-, and spectrometer parameters. From this then general prescriptions for optimizing the resolution by matching the beam handling and the detector system are derived. Explicitly treated are the measurements of Q-values and CM-scattering angle with an energy sensitive detector, a time of flight spectrometer, and a magnetic spectrometer. (orig.) [de

  6. MO-F-CAMPUS-I-04: Characterization of Fan Beam Coded Aperture Coherent Scatter Spectral Imaging Methods for Differentiation of Normal and Neoplastic Breast Structures

    Energy Technology Data Exchange (ETDEWEB)

    Morris, R; Albanese, K; Lakshmanan, M; Greenberg, J; Kapadia, A [Duke University Medical Center, Durham, NC, Carl E Ravin Advanced Imaging Laboratories, Durham, NC (United States)

    2015-06-15

    Purpose: This study intends to characterize the spectral and spatial resolution limits of various fan beam geometries for differentiation of normal and neoplastic breast structures via coded aperture coherent scatter spectral imaging techniques. In previous studies, pencil beam raster scanning methods using coherent scatter computed tomography and selected volume tomography have yielded excellent results for tumor discrimination. However, these methods don’t readily conform to clinical constraints; primarily prolonged scan times and excessive dose to the patient. Here, we refine a fan beam coded aperture coherent scatter imaging system to characterize the tradeoffs between dose, scan time and image quality for breast tumor discrimination. Methods: An X-ray tube (125kVp, 400mAs) illuminated the sample with collimated fan beams of varying widths (3mm to 25mm). Scatter data was collected via two linear-array energy-sensitive detectors oriented parallel and perpendicular to the beam plane. An iterative reconstruction algorithm yields images of the sample’s spatial distribution and respective spectral data for each location. To model in-vivo tumor analysis, surgically resected breast tumor samples were used in conjunction with lard, which has a form factor comparable to adipose (fat). Results: Quantitative analysis with current setup geometry indicated optimal performance for beams up to 10mm wide, with wider beams producing poorer spatial resolution. Scan time for a fixed volume was reduced by a factor of 6 when scanned with a 10mm fan beam compared to a 1.5mm pencil beam. Conclusion: The study demonstrates the utility of fan beam coherent scatter spectral imaging for differentiation of normal and neoplastic breast tissues has successfully reduced dose and scan times whilst sufficiently preserving spectral and spatial resolution. Future work to alter the coded aperture and detector geometries could potentially allow the use of even wider fans, thereby making coded

  7. Measurement of the neutron fields produced by a 62 MeV proton beam on a PMMA phantom using extended range Bonner sphere spectrometers

    International Nuclear Information System (INIS)

    Amgarou, K.; Bedogni, R.; Domingo, C.; Esposito, A.; Gentile, A.; Carinci, G.; Russo, S.

    2011-01-01

    The experimental characterization of the neutron fields produced as parasitic effect in medical accelerators is assuming an increased importance for either the patient protection or the facility design aspects. Medical accelerators are diverse in terms of particle type (electrons or hadrons) and energy, but the radiation fields around them have in common (provided that a given threshold energy is reached) the presence of neutrons with energy span over several orders of magnitude. Due to the large variability of neutron energy, field or dosimetry measurements in these workplaces are very complex, and in general, cannot be performed with ready-to-use commercial instruments. In spite of its poor energy resolution, the Bonner Sphere Spectrometer (BSS) is the only instrument able to simultaneously determine all spectral components in such workplaces. The energy range of this instrument is limited to E o and 90 o with respect to the beam-line. Here the ERBSS of UAB (Universidad Autonoma de Barcelona-Grup de Fisica de les Radiacions) and INFN (Istituto Nazionale di Fisica Nucleare-Laboratori Nazionali di Frascati) were exposed to characterize the 'forward' and 'sideward' proton-induced neutron fields. The use of two ERBSS characterized by different set of spheres, central detectors, and independently established and calibrated, is important for guaranteeing the robustness of the measured spectra and estimating their overall uncertainties.

  8. Beam-spin asymmetry of pion, kaon, proton and antiproton production in semi-inclusive deep-inelastic scattering

    Energy Technology Data Exchange (ETDEWEB)

    Zagrebelnyy, Vitaly [DESY Hamburg Notkestrasse 85 (Germany)

    2014-07-01

    Beam-spin asymmetries in the azimuthal distribution of pions, kaons, protons and antiprotons in semi-inclusive deep inelastic scattering (SIDIS) extracted from 2000-2007 HERMES data are presented. The asymmetries were measured in the kinematic region Q{sup 2}>1 GeV{sup 2}, W{sup 2} > 10 GeV{sup 2}, 0.1

  9. Neutron angular distribution in (γ, n reactions with linearly polarized γ-ray beam generated by laser Compton scattering

    Directory of Open Access Journals (Sweden)

    K. Horikawa

    2014-10-01

    Full Text Available In 1957, Agodi predicted that the neutron angular distribution in (γ, n reactions with a 100% linearly polarized γ-ray beam for dipole excitation should be anisotropic and universally described by the simple function of a+b⋅cos⁡(2ϕ at the polar angle θ=90°, where ϕ is the azimuthal angle. However, this prediction has not been experimentally confirmed in over half a century. We have verified experimentally this angular distribution in the (γ, n reaction for 197Au, 127I, and natural Cu targets using linearly polarized laser Compton scattering γ-rays. The result suggests that the (γ→, n reaction is a novel tool to study nuclear physics in the giant dipole resonance region.

  10. Correlation spectrometer

    Science.gov (United States)

    Sinclair, Michael B [Albuquerque, NM; Pfeifer, Kent B [Los Lunas, NM; Flemming, Jeb H [Albuquerque, NM; Jones, Gary D [Tijeras, NM; Tigges, Chris P [Albuquerque, NM

    2010-04-13

    A correlation spectrometer can detect a large number of gaseous compounds, or chemical species, with a species-specific mask wheel. In this mode, the spectrometer is optimized for the direct measurement of individual target compounds. Additionally, the spectrometer can measure the transmission spectrum from a given sample of gas. In this mode, infrared light is passed through a gas sample and the infrared transmission signature of the gasses present is recorded and measured using Hadamard encoding techniques. The spectrometer can detect the transmission or emission spectra in any system where multiple species are present in a generally known volume.

  11. Trapping mechanisms in scattering of beams at grazing incidence from crystals

    International Nuclear Information System (INIS)

    Smith, R.; O'Connor, D.J.; Felsobuki, E.I. von-Nagy

    1993-01-01

    The trajectories of grazing incidence, 1 keV beams of Si incident on Cu{111} are investigated by means of molecular dynamics (MD) simulations and the conditions under which atoms in the beam can be trapped in the surface binding potential are investigated. The binding potentials for the Cu-Si dimers are calculated using ab initio methods for the neutral, anion and cation. These calculations estimate the binding potential and equilibrium separation for the potential used for the MD calculations. It is found that at 4 o incidence to the Cu{111} face, no trapping occurs for a perfect crystal surface undergoing no thermal vibrations. Trapping can occur for the Si neutral if thermal vibrations are included in the model. Trapping is predicted to occur near steps on the Cu{111} face but these are fairly rare events for the Si - particles. (Author)

  12. Measurement of the neutron fields produced by a 62 MeV proton beam on a PMMA phantom using extended range Bonner sphere spectrometers

    Energy Technology Data Exchange (ETDEWEB)

    Amgarou, K. [Grup de Recerca en Radiacions Ionitzants, Departament de Fisica, Universitat Autonoma de Barcelona, E-08193 Bellaterra (Spain); Bedogni, R., E-mail: roberto.bedogni@lnf.infn.it [INFN-Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati, Via E. Fermi n. 40, 00044 Frascati (Italy); Domingo, C. [Grup de Recerca en Radiacions Ionitzants, Departament de Fisica, Universitat Autonoma de Barcelona, E-08193 Bellaterra (Spain); Esposito, A.; Gentile, A.; Carinci, G. [INFN-Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati, Via E. Fermi n. 40, 00044 Frascati (Italy); Russo, S. [INFN-Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, via S. Sofia 44, 95123 Catania (Italy)

    2011-10-21

    The experimental characterization of the neutron fields produced as parasitic effect in medical accelerators is assuming an increased importance for either the patient protection or the facility design aspects. Medical accelerators are diverse in terms of particle type (electrons or hadrons) and energy, but the radiation fields around them have in common (provided that a given threshold energy is reached) the presence of neutrons with energy span over several orders of magnitude. Due to the large variability of neutron energy, field or dosimetry measurements in these workplaces are very complex, and in general, cannot be performed with ready-to-use commercial instruments. In spite of its poor energy resolution, the Bonner Sphere Spectrometer (BSS) is the only instrument able to simultaneously determine all spectral components in such workplaces. The energy range of this instrument is limited to E<20 MeV if only polyethylene spheres are used, but can be extended to hundreds of MeV by including metal-loaded spheres (extended range BSS, indicated with ERBSS). With the aim of providing useful data to the scientific community involved in neutron measurements at hadron therapy facilities, an ERBSS experiment was carried out at the Centro di AdroTerapia e Applicazioni Nucleari Avanzate (CATANA) of INFN-LNS (Laboratori Nazionali del Sud), where a proton beam routinely used for ophthalmic cancer treatments is available. The 62 MeV beam was directed towards a PMMA phantom, simulating the patient, and two neutron measurement points were established at 0{sup o} and 90{sup o} with respect to the beam-line. Here the ERBSS of UAB (Universidad Autonoma de Barcelona-Grup de Fisica de les Radiacions) and INFN (Istituto Nazionale di Fisica Nucleare-Laboratori Nazionali di Frascati) were exposed to characterize the 'forward' and 'sideward' proton-induced neutron fields. The use of two ERBSS characterized by different set of spheres, central detectors, and

  13. Raman scattering and Rutherford backscattering studies on InN films grown by plasma-assisted molecular beam epitaxy

    International Nuclear Information System (INIS)

    Chung, Yee Ling; Peng Xingyu; Liao, Ying Chieh; Yao Shude; Chen, Li Chyong; Chen, Kuei Hsien; Feng, Zhe Chuan

    2011-01-01

    A series of InN thin films was grown on sapphire substrates via plasma-assisted molecular beam epitaxy (PA-MBE) with different nitrogen plasma power. Various characterization techniques, including Hall, photoluminescence, Raman scattering and Rutherford backscattering, have been employed to study these InN films. Good crystalline wurtzite structures have been identified for all PA-MBE grown InN films on sapphire substrate, which have narrower XRD wurtzite (0002) peaks, showed c-axis Raman scattering allowed longitudinal optical (LO) modes of A 1 and E 1 plus E 2 symmetry, and very weak backscattering forbidden transverse optical (TO) modes. The lower plasma power can lead to the lower carrier concentration, to have the InN film close to intrinsic material with the PL emission below 0.70 eV. With increasing the plasma power, high carrier concentration beyond 1 x 10 20 cm -3 can be obtained, keeping good crystalline perfection. Rutherford backscattering confirmed most of InN films keeping stoichiometrical In/N ratios and only with higher plasma power of 400 W leaded to obvious surface effect and interdiffusion between the substrate and InN film.

  14. X-Band Linac Beam-Line for Medical Compton Scattering X-Ray Source

    CERN Document Server

    Dobashi, Katsuhiro; Ebina, Futaro; Fukasawa, Atsushi; Hayano, Hitoshi; Higo, Toshiyasu; Kaneyasu, Tatsuo; Ogino, Haruyuki; Sakamoto, Fumito; Uesaka, Mitsuru; Urakawa, Junji; Yamamoto, Tomohiko

    2005-01-01

    Compton scattering hard X-ray source for 10~80 keV are under construction using the X-band (11.424 GHz) electron linear accelerator and YAG laser at Nuclear Engineering Research laboratory, University of Tokyo. This work is a part of the national project on the development of advanced compact medical accelerators in Japan. National Institute for Radiological Science is the host institute and U. Tokyo and KEK are working for the X-ray source. Main advantage is to produce tunable monochromatic hard ( 10-80

  15. Optimized design for the scattering with angular limitation in projection electron-beam lithography based electron projection system

    International Nuclear Information System (INIS)

    Xiu, K.; Gibson, J. M.

    2000-01-01

    We investigate the design for a scattering with angular limitation in projection electron-beam lithography (SCALPEL) based electron projection system with a demagnification of -4. By a ''field-flip'' process we can construct a doublet in which the magnetic field has a flat feature in most of the optic column but opposite sign at two sides connected by a sharp transition region. Such a theoretical model can give a near zero chromatic aberration of rotation and much smaller field curvature and astigmatism. Compared with the conventional doublet, the total image blur caused by aberrations at 1/√(2) mm off-axis distance and 1.5 mrad semiangle aperture at the mask side is about only 24 nm for a column length of 400 mm. A shorter column, less than the current 400 mm, is also favored for further reducing the total aberration. These guarantee that we can choose a much larger aperture angle (compared with present 0.5 mrad) and beam current density in such a SCALPEL projection system to achieve higher throughput while still maintaining current resolution. A practical issue for possible magnetic lens design is also discussed. (c) 2000 American Vacuum Society

  16. Measurement of charged current deep inelastic scattering cross sections with a longitudinally polarised electron beam at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Chekanov, S.; Derrick, M.; Magill, S. [Argonne National Laboratory, IL (US)] (and others)

    2008-12-15

    Measurements of the cross sections for charged current deep inelastic scattering in e{sup -}p collisions with longitudinally polarised electron beams are presented. The measurements are based on a data sample with an integrated luminosity of 175 pb{sup -1} collected with the ZEUS detector at HERA at a centre-of-mass energy of 318 GeV. The total cross section is given for positively and negatively polarised electron beams. The differential cross-sections d{sigma}/dQ{sup 2}, d{sigma}/dx and d{sigma}/dy are presented for Q{sup 2}>200 GeV{sup 2}. The double-differential cross-section d{sup 2}{sigma}/dxdQ{sup 2} is presented in the kinematic range 280

  17. Study of the elastic scattering differential cross sections of a proton beam by a cesium target

    International Nuclear Information System (INIS)

    El Maddarsi, Mohamed.

    1978-01-01

    The elastic differential cross section of H + on Cs is studied experimentally and theoretically. The experimental device is described, after which the differential cross-section values obtained as a function of the laboratory angle are given for four incident energies: 13.4 eV, 15.1 eV, 17.7 eV and 24.2 eV. By means of an interaction potential of the quasi-molecule H + Cs the differential cross sections are calculated for the same incident energies; this calculation uses the semi-classical method of stationary phases which shows clearly the limits of conventional description and the changes introduced by quantum effects. Very good agreement is obtained between theoretical and experimental results, which shows that elastic scattering is very little perturbed by inelastic channels in this energy range. The estimated inelastic cross section at 24 eV is about 1.9 10 -15 cm 2 , corresponding to 1.6% of the scattering process [fr

  18. Multidimensional spectrometer

    Science.gov (United States)

    Zanni, Martin Thomas; Damrauer, Niels H.

    2010-07-20

    A multidimensional spectrometer for the infrared, visible, and ultraviolet regions of the electromagnetic spectrum, and a method for making multidimensional spectroscopic measurements in the infrared, visible, and ultraviolet regions of the electromagnetic spectrum. The multidimensional spectrometer facilitates measurements of inter- and intra-molecular interactions.

  19. Analysis of material characteristics for the construction of energy degrading and scattering plates for electron beam skin radiotherapy

    International Nuclear Information System (INIS)

    Fonseca, Gabriel P.; Yoriyaz, Helio; Siqueira, Paulo T.D.; Antunes, Paula C.G.; Furnari, Laura; Santos, Gabriela R.

    2009-01-01

    There are many radiosensitive diseases associated to the skin such as mycosis fungoids and the syndrome of Sezary that are part of a sub-group of cutaneous diseases type T-cell lymphoma. Several studies indicate the eradication of the disease when treated with linear accelerators emitting electron beams with energies between 4 to 10 MeV. However, this treatment technique presents innumerable technical challenges since the disease in general reaches all patient's body, becoming necessary a very large field size radiation beam, and also, it should deliver superficial doses limited to the skin depth. To reach the uniformity in the dose distribution, many techniques had already been developed. Based on these previous studies and guided by the report nr. 23 of the AAPM (American Association of Physicists in Medicine), the present study will develop an energy scattering and degrading plates, supplying subsidies for a future installation for skin treatment at the - Servico de Radioterapia do Hospital das Clinicas de Sao Paulo. As part of the plates design, first of all, the energy spectrum of the 6 MeV electron beam of the VARIAN 2100C accelerator was reconstructed through Monte Carlo simulations using the MCNP4C code and based on experimental data. Once the spectrum is built the design of the plates has been performed analyzing several materials, shapes and dimensions most adequate on the basis of radial and axial dose distribution, production of rays-x and dose attenuation. The simulations will be validated with experimental measurements using copper and aluminum. (author)

  20. Out-of-Field Dose Equivalents Delivered by Passively Scattered Therapeutic Proton Beams for Clinically Relevant Field Configurations

    International Nuclear Information System (INIS)

    Wroe, Andrew; Clasie, Ben; Kooy, Hanne; Flanz, Jay; Schulte, Reinhard; Rosenfeld, Anatoly

    2009-01-01

    Purpose: Microdosimetric measurements were performed at Massachusetts General Hospital, Boston, MA, to assess the dose equivalent external to passively delivered proton fields for various clinical treatment scenarios. Methods and Materials: Treatment fields evaluated included a prostate cancer field, cranial and spinal medulloblastoma fields, ocular melanoma field, and a field for an intracranial stereotactic treatment. Measurements were completed with patient-specific configurations of clinically relevant treatment settings using a silicon-on-insulator microdosimeter placed on the surface of and at various depths within a homogeneous Lucite phantom. The dose equivalent and average quality factor were assessed as a function of both lateral displacement from the treatment field edge and distance downstream of the beam's distal edge. Results: Dose-equivalent value range was 8.3-0.3 mSv/Gy (2.5-60-cm lateral displacement) for a typical prostate cancer field, 10.8-0.58 mSv/Gy (2.5-40-cm lateral displacement) for the cranial medulloblastoma field, 2.5-0.58 mSv/Gy (5-20-cm lateral displacement) for the spinal medulloblastoma field, and 0.5-0.08 mSv/Gy (2.5-10-cm lateral displacement) for the ocular melanoma field. Measurements of external field dose equivalent for the stereotactic field case showed differences as high as 50% depending on the modality of beam collimation. Average quality factors derived from this work ranged from 2-7, with the value dependent on the position within the phantom in relation to the primary beam. Conclusions: This work provides a valuable and clinically relevant comparison of the external field dose equivalents for various passively scattered proton treatment fields

  1. Time collimation for elastic neutron scattering instrument at a pulsed source

    International Nuclear Information System (INIS)

    Aksenov, V.L.; Nikitenko, Yu.V.

    1996-01-01

    Conditions for carrying out elastic neutron scattering experiments using the time-of-flight technique are considered. It is shown that the employment of time dependent neutron beam collimation in the source-sample flight path increases the luminosity of the spectrometer under certain resolution restrictions. 3 refs., 8 figs

  2. Polarized epithermal neutron spectrometer at KENS

    International Nuclear Information System (INIS)

    Kohgi, M.

    1983-01-01

    A spectrometer employing a white, epithermal, polarized neutron beam is under construction at KENS. The neutron polarization is achieved by passage through a dynamically polarized proton filter (DPPF). The results of the test experiments show that the DPPF method is promising in obtaining polarized epithermal neutron beam. The basic design of the spectrometer is described

  3. Generation and application of soft-X-ray by means of inverse compton scattering between high quality election beam and IR laser

    International Nuclear Information System (INIS)

    Washio, M.; Sakaue, K.; Hama, Y.; Kamiya, Y.; Moriyama, R.; Hezume, K.; Saito, T.; Kuroda, R.; Kashiwagi, S.; Ushida, K.; Hayano, H.; Urakawa, J.

    2006-01-01

    High quality beam generation project based on High-Tech Research Center Project, which has been approved by Ministry of Education, Culture, Sports, Science and Technology in 1999, has been conducted by advance research institute for science and engineering, Waseda University. In the project, laser photo-cathode RF-gun has been selected for the high quality electron beam source. RF cavities with low dark current, which were made by diamond turning technique, have been successfully manufactured. The low emittance electron beam was realized by choosing the modified laser injection technique. The obtained normalized emittance was about 3 mm·mrad at 100 pC of electron charge. The soft X-ray beam generation with the energy of 370 eV, which is in the energy region of so-called 'water window', by inverse Compton scattering has been performed by the collision between IR laser and the low emittance electron beams. (authors)

  4. Study of MPI based on parallel MOM on PC clusters for EM-beam scattering by 2-D PEC rough surfaces

    International Nuclear Information System (INIS)

    Jun, Ma; Li-Xin, Guo; An-Qi, Wang

    2009-01-01

    This paper firstly applies the finite impulse response filter (FIR) theory combined with the fast Fourier transform (FFT) method to generate two-dimensional Gaussian rough surface. Using the electric field integral equation (EFIE), it introduces the method of moment (MOM) with RWG vector basis function and Galerkin's method to investigate the electromagnetic beam scattering by a two-dimensional PEC Gaussian rough surface on personal computer (PC) clusters. The details of the parallel conjugate gradient method (CGM) for solving the matrix equation are also presented and the numerical simulations are obtained through the message passing interface (MPI) platform on the PC clusters. It finds significantly that the parallel MOM supplies a novel technique for solving a two-dimensional rough surface electromagnetic-scattering problem. The influences of the root-mean-square height, the correlation length and the polarization on the beam scattering characteristics by two-dimensional PEC Gaussian rough surfaces are finally discussed. (classical areas of phenomenology)

  5. A high resolution x-ray fluorescence spectrometer for near edge absorption studies

    International Nuclear Information System (INIS)

    Stojanoff, V.; Hamalainen, K.; Siddons, D.P.; Hastings, J.B.; Berman, L.E.; Cramer, S.; Smith, G.

    1991-01-01

    A high resolution fluorescence spectrometer using a Johann geometry in a back scattering arrangement was developed. The spectrometer, with a resolution of 0.3 eV at 6.5 keV, combined with an incident beam, with a resolution of 0.7 eV, form the basis of a high resolution instrument for measuring x-ray absorption spectra. The advantages of the instrument are illustrated with the near edge absorption spectrum of dysprosium nitrate. 10 refs., 4 figs

  6. Size constraints on a Majorana beam-splitter interferometer: Majorana coupling and surface-bulk scattering

    Science.gov (United States)

    Røising, Henrik Schou; Simon, Steven H.

    2018-03-01

    Topological insulator surfaces in proximity to superconductors have been proposed as a way to produce Majorana fermions in condensed matter physics. One of the simplest proposed experiments with such a system is Majorana interferometry. Here we consider two possibly conflicting constraints on the size of such an interferometer. Coupling of a Majorana mode from the edge (the arms) of the interferometer to vortices in the center of the device sets a lower bound on the size of the device. On the other hand, scattering to the usually imperfectly insulating bulk sets an upper bound. From estimates of experimental parameters, we find that typical samples may have no size window in which the Majorana interferometer can operate, implying that a new generation of more highly insulating samples must be explored.

  7. 4D cone-beam computed tomography (CBCT) using a moving blocker for simultaneous radiation dose reduction and scatter correction

    Science.gov (United States)

    Zhao, Cong; Zhong, Yuncheng; Duan, Xinhui; Zhang, You; Huang, Xiaokun; Wang, Jing; Jin, Mingwu

    2018-06-01

    Four-dimensional (4D) x-ray cone-beam computed tomography (CBCT) is important for a precise radiation therapy for lung cancer. Due to the repeated use and 4D acquisition over a course of radiotherapy, the radiation dose becomes a concern. Meanwhile, the scatter contamination in CBCT deteriorates image quality for treatment tasks. In this work, we propose the use of a moving blocker (MB) during the 4D CBCT acquisition (‘4D MB’) and to combine motion-compensated reconstruction to address these two issues simultaneously. In 4D MB CBCT, the moving blocker reduces the x-ray flux passing through the patient and collects the scatter information in the blocked region at the same time. The scatter signal is estimated from the blocked region for correction. Even though the number of projection views and projection data in each view are not complete for conventional reconstruction, 4D reconstruction with a total-variation (TV) constraint and a motion-compensated temporal constraint can utilize both spatial gradient sparsity and temporal correlations among different phases to overcome the missing data problem. The feasibility simulation studies using the 4D NCAT phantom showed that 4D MB with motion-compensated reconstruction with 1/3 imaging dose reduction could produce satisfactory images and achieve 37% improvement on structural similarity (SSIM) index and 55% improvement on root mean square error (RMSE), compared to 4D reconstruction at the regular imaging dose without scatter correction. For the same 4D MB data, 4D reconstruction outperformed 3D TV reconstruction by 28% on SSIM and 34% on RMSE. A study of synthetic patient data also demonstrated the potential of 4D MB to reduce the radiation dose by 1/3 without compromising the image quality. This work paves the way for more comprehensive studies to investigate the dose reduction limit offered by this novel 4D MB method using physical phantom experiments and real patient data based on clinical relevant metrics.

  8. A neutron spectrometer based on the combination of time-of-flight and Larmor modulation

    International Nuclear Information System (INIS)

    Mulder, F.M.; Kreuger, R.; Grigoriev, S.V.; Kraan, W.H.; Rekveldt, M.Th.; Van Well, A.A.

    1999-01-01

    A study on the feasibility of neutron beam instrumentation that applies Larmor modulation for incoming, and time-of-flight for scattered wavelength determination (or vice versa) is currently under way at IRI. The instrument resulting from this combination can in principle measure quasi elastic and inelastic scattering with a flexible resolution and dynamic range. An important difference with current spectrometers is that there is no selection of neutron wavelengths for either the incoming beam (direct geometry) or scattered beam (inverted geometry). Therefore much of the available flux is used and there is no a priory selection of the energy transfer range and resolution. This instrument will be mainly applicable for quasi-elastic scattering and complex line shapes that are extended over a broad range in energy transfer. Line shapes can be measured directly in Fourier space, which is often advantageous. Due to signal to noise considerations, this instrument will be less suitable for the determination of weak, discrete energy transfer signals. A requirement for the Larmor modulator is that it can work with a white neutron beam. This can be realised for neutrons having a wavelength above ∼ 0.1 nm by use of 'adiabatic resonance π flippers'. This type of instrument may be applied at the future ESS pulsed neutron source in order to complement current spectrometers. (author)

  9. Study of the elastic scattering and of the (p,n) charge exchange reaction with neutron-rich light exotic beams; Etude de la diffusion elastique et de la reaction d`echange de charge (p,n) avec des faisceaux exotiques legers riches en neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Cortina Gil, D.

    1996-07-05

    We have measured at GANIL, with the high resolution spectrometer SPEG, the elastic scattering of several neutron rich secondary beams ({sup 6}He, {sup 10}Be and {sup 11}Be) on a polypropylene target and the charge exchange reaction p({sup 6}He, {sup 6}Li)n. These exotic beams were produced by nuclear fragmentation and re-focalized with the SISSI device (superconducting solenoids). The signature of a halo structure in these nuclei has been analysed. Special attention has been paid to several aspects of the associated calculations namely, the proton and neutron density distributions and the small binding energy for the last nucleons in these exotic nuclei. Break-up mechanisms are seen to play an important role in these nuclei. 100 refs.

  10. The high-resolution time-of-flight spectrometer TOFTOF

    Energy Technology Data Exchange (ETDEWEB)

    Unruh, Tobias [Technische Universitaet Muenchen, Forschungsneutronenquelle Heinz Maier-Leibnitz FRM II and Physik Department E13, Lichtenbergstr. 1, 85747 Garching (Germany)], E-mail: Tobias.Unruh@frm2.tum.de; Neuhaus, Juergen; Petry, Winfried [Technische Universitaet Muenchen, Forschungsneutronenquelle Heinz Maier-Leibnitz FRM II and Physik Department E13, Lichtenbergstr. 1, 85747 Garching (Germany)

    2007-10-11

    The TOFTOF spectrometer is a multi-disc chopper time-of-flight spectrometer for cold neutrons at the research neutron source Heinz Maier-Leibnitz (FRM II). After five reactor cycles of routine operation the characteristics of the instrument are reported in this article. The spectrometer features an excellent signal to background ratio due to its remote position in the neutron guide hall, an elaborated shielding concept and an s-shaped curved primary neutron guide which acts i.a. as a neutron velocity filter. The spectrometer is fed with neutrons from the undermoderated cold neutron source of the FRM II leading to a total neutron flux of {approx}10{sup 10}n/cm{sup 2}/s in the continuous white beam at the sample position distributed over a continuous and particularly broad wavelength spectrum. A high energy resolution is achieved by the use of high speed chopper discs made of carbon-fiber-reinforced plastic. In the combination of intensity, resolution and signal to background ratio the spectrometer offers new scientific prospects in the fields of inelastic and quasielastic neutron scattering.

  11. The high-resolution time-of-flight spectrometer TOFTOF

    Science.gov (United States)

    Unruh, Tobias; Neuhaus, Jürgen; Petry, Winfried

    2007-10-01

    The TOFTOF spectrometer is a multi-disc chopper time-of-flight spectrometer for cold neutrons at the research neutron source Heinz Maier-Leibnitz (FRM II). After five reactor cycles of routine operation the characteristics of the instrument are reported in this article. The spectrometer features an excellent signal to background ratio due to its remote position in the neutron guide hall, an elaborated shielding concept and an s-shaped curved primary neutron guide which acts i.a. as a neutron velocity filter. The spectrometer is fed with neutrons from the undermoderated cold neutron source of the FRM II leading to a total neutron flux of ˜1010n/cm2/s in the continuous white beam at the sample position distributed over a continuous and particularly broad wavelength spectrum. A high energy resolution is achieved by the use of high speed chopper discs made of carbon-fiber-reinforced plastic. In the combination of intensity, resolution and signal to background ratio the spectrometer offers new scientific prospects in the fields of inelastic and quasielastic neutron scattering.

  12. Use of primary beam filtration in estimating mass attenuation coefficients by Compton scattering

    International Nuclear Information System (INIS)

    O'Connor, B.H.; Chang, W.J.

    1985-01-01

    Mass attenuation coefficients (MACs) are frequently estimated over a range of wavelengths in x-ray spectrometry from the intensity of the Compton peak I /SUB C/ associated with a prominent tube line. The MAC μ /SUB ll/ at wavelength lambda is estimated from the MAC at the Compton wavelength lambda /SUB C/ with the approximations μ /SUB ll/ α μ /SUB C/ and μ /SUB C/ α l/I /SUB C/ , Systematic errors may introduce absorption edge bias (AEB) effects into the results, caused by sample components with absorption edges between lambda /SUB C/ and lambda. A procedure is described which eliminates AEB effects by measuring I /SUB C/ using emission radiation from a primary beam filter

  13. Void fraction measurements in two-phase flow by transmission and scattering of a neutrons beam

    International Nuclear Information System (INIS)

    Souza, M.C.L.

    1984-01-01

    Calibration curves have been obtained which supply average values of void fraction (α) of water-steam two-phase mixtures for bubble, slug, annular and invert annular flow states. The measurements were carried out in simulated models of lucite-air for the steady-state, using the techniques of transmission and diffusion of a thermal neutrons beam. The calibration curves obtained were used for measurements of void fraction in a circuit containing two-phase water-air mixtures, in upward concurrent flow, for slug flow (P sub(max) = 1,06 bar) and annular flow (P sub(max) = 1,33 bar), using the same techniques. In both of the systems, a test section made up of an aluminium (99,9%) tube was used with internal diameter of 25,25 mm and 2,0 mm wall thichness. The beam of neutrons was obtained from a 5 Ci isotopic Am-Be source, thermalised in a cylindrical moderator of paraffin of 500 mm diameter (with H/D=1) which was covered by 2 mm thick cadmium sheets and having in its centre a parallepeliped made from high density polyethilene with the dimensions 240 x 240 x 144 mm. The neutrons escape through a rectangular collimator of 53,0 x 25,25 mm, with a length of 273 mm cut out of a single block of borated paraffin (32% of H 3 BO 3 ). The experimental results are in good agreement with theorical models in published literature. (Author) [pt

  14. Parametrisation of the collimator scatter correction factors of square and rectangular photon beams

    International Nuclear Information System (INIS)

    Jager, H.N.; Heukelom, S.; Kleffens, H.J. van; Gasteren, J.J.M. van; Laarse, R. van der; Venselaar, J.L.M.; Westermann, C.F.

    1995-01-01

    Collimator scatter correction factors S c have been measured with a cylindrical mini-phantom for five types of dual photon energy accelerators with energies between 6 and 25 MV. Using these S c -data three methods to parametrize S c of square fields have been compared including a third-order polynomial of the natural logarithm of the fieldsize normalised by the fieldsize of 10 cm 2 . Also six methods to calculate S c of rectangular fields have been compared including a new one which determines the equivalent fieldsize by extending Sterling's method. The deviation between measured and calculated S c for every accelerator, energy and all methods are determined resulting in the maximum and average deviation per method. Applied to square fields the maximum and average deviation were for the method of Chen 0.64% and 0.15%, of Szymzcyk 0.98% and 0.21%, and of this work 0.41% and 0.10%. For the rectangular fields the deviations were for the method of Sterling 1.89% and 0.50%, of Vadash 1.60% and 0.28%, of Szymczyk et al. 1.21% and 0.25%, of Chen 1.84% and 0.31% and of this work 0.79% and 0.20%. Finally, a recommendation is given how to limit the number of fields at which S c should be measured

  15. A laser particulate spectrometer for a space simulation facility

    Science.gov (United States)

    Schmitt, R. J.; Boyd, B. A.; Linford, R. M. F.; Richmond, R. G.

    1975-01-01

    A laser particulate spectrometer (LPS) system was developed to measure the size and speed distributions of particulate contaminants. Detection of the particulates is achieved by means of light scattering and extinction effects using a single laser beam to cover a size range of 0.8 to 275 microns diameter and a speed range of 0.2 to 20 meters/second. The LPS system was designed to operate in the high-vacuum environment of a space simulation chamber with cold shroud temperatures ranging from 77 to 300 K.

  16. Depth Dose Measurement using a Scintillating Fiber Optic Dosimeter for Proton Therapy Beam of the Passive-Scattering Mode Having Range Modulator Wheel

    Science.gov (United States)

    Hwang, Ui-Jung; Shin, Dongho; Lee, Se Byeong; Lim, Young Kyung; Jeong, Jong Hwi; Kim, Hak Soo; Kim, Ki Hwan

    2018-05-01

    To apply a scintillating fiber dosimetry system to measure the range of a proton therapy beam, a new method was proposed to correct for the quenching effect on measuring an spread out Bragg peak (SOBP) proton beam whose range is modulated by a range modulator wheel. The scintillating fiber dosimetry system was composed of a plastic scintillating fiber (BCF-12), optical fiber (SH 2001), photo multiplier tube (H7546), and data acquisition system (PXI6221 and SCC68). The proton beam was generated by a cyclotron (Proteus-235) in the National Cancer Center in Korea. It operated in the double-scattering mode and the spread out of the Bragg peak was achieved by a spinning range modulation wheel. Bragg peak beams and SOBP beams of various ranges were measured, corrected, and compared to the ion chamber data. For the Bragg peak beam, quenching equation was used to correct the quenching effect. On the proposed process of correcting SOBP beams, the measured data using a scintillating fiber were separated by the Bragg peaks that the SOBP beam contained, and then recomposed again to reconstruct an SOBP after correcting for each Bragg peak. The measured depth-dose curve for the single Bragg peak beam was well corrected by using a simple quenching equation. Correction for SOBP beam was conducted with a newly proposed method. The corrected SOBP signal was in accordance with the results measured with an ion chamber. We propose a new method to correct for the SOBP beam from the quenching effect in a scintillating fiber dosimetry system. This method can be applied to other scintillator dosimetry for radiation beams in which the quenching effect is shown in the scintillator.

  17. Improving neutron spectrometer performances through spatial and focusing effects: Investigation of spatial correlation focusing influence on the resolution in diffraction and phonon scattering experiments

    International Nuclear Information System (INIS)

    Popovici, M.

    1986-09-01

    A consistent treatment of the optics of three-axis spectrometers with curved perfect crystals, the gradient of lattice spacing accounted for, is presented. The mosaic crystal case is treated within the same computational scheme. From the computational point of view, the perfect crystals case is not the zero mosaic spread limit of the mosaic crystals case. The estimation of the residual line-widths in conditions of reciprocal-space focusing allows the discussion of the possibilities and limitations of using spatial correlation effects for improving spectrometer performances. A computer programme is presented which makes it possible to calculate both analytically and numerically the optimal arrangements and the deviations of the optimal parameter values. The optimization of parameters not involved in the analytically expressed reciprocal-space focusing conditions is also possible with this programme. The experimental results presented in this paper show that both the line-widths and the absolute intensities can also be described with reasonable accuracy for the perfect curved crystals case. It is shown experimentally that even at low-flux reactors one can obtain with the aid of perfect curved crystals good resolutions at measurable intensities which are generally higher than those obtainable in conventional spectrometers with flat mosaic crystals

  18. A superconducting electron spectrometer

    International Nuclear Information System (INIS)

    Guttormsen, M.; Huebel, H.; Grumbkow, A. von

    1983-03-01

    The set-up and tests of an electron spectrometer for in-beam conversion electron measurements are described. A superconducting solenoid is used to transport the electrons from the target to cooled Si(Li) detectors. The solenoid is designed to produce either a homogeneous axially symmetric field of up to 2 Tesla or a variety of field profiles by powering the inner and outer set of coils of the solenoid separately. The electron trajectories resulting for various field profiles are discussed. In-beam electron spectra taken in coincidence with electrons, gammas and alpha-particles are shown. (Auth.)

  19. Evaluation of a method for correction of scatter radiation in thorax cone beam CT; Evaluation d'une methode de correction du rayonnement diffuse en tomographie du thorax avec faisceau conique

    Energy Technology Data Exchange (ETDEWEB)

    Rinkel, J.; Dinten, J.M. [CEA Grenoble (DTBS/STD), Lab. d' Electronique et de Technologie de l' Informatique, LETI, 38 (France); Esteve, F. [European Synchrotron Radiation Facility (ESRF), 38 - Grenoble (France)

    2004-07-01

    Purpose: Cone beam CT (CBCT) enables three-dimensional imaging with isotropic resolution. X-ray scatter estimation is a big challenge for quantitative CBCT imaging of thorax: scatter level is significantly higher on cone beam systems compared to collimated fan beam systems. The effects of this scattered radiation are cupping artefacts, streaks, and quantification inaccuracies. The beam stops conventional scatter estimation approach can be used for CBCT but leads to a significant increase in terms of dose and acquisition time. At CEA-LETI has been developed an original scatter management process without supplementary acquisition. Methods and Materials: This Analytical Plus Indexing-based method (API) of scatter correction in CBCT is based on scatter calibration through offline acquisitions with beam stops on lucite plates, combined to an analytical transformation issued from physical equations. This approach has been applied with success in bone densitometry and mammography. To evaluate this method in CBCT, acquisitions from a thorax phantom with and without beam stops have been performed. To compare different scatter correction approaches, Feldkamp algorithm has been applied on rough data corrected from scatter by API and by beam stops approaches. Results: The API method provides results in good agreement with the beam stops array approach, suppressing cupping artefact. Otherwise influence of the scatter correction method on the noise in the reconstructed images has been evaluated. Conclusion: The results indicate that the API method is effective for quantitative CBCT imaging of thorax. Compared to a beam stops array method it needs a lower x-ray dose and shortens acquisition time. (authors)

  20. CAPTAIN-Miner@@a. Neutrino-Argon Scattering in a Medium-Energy Neutrino Beam

    International Nuclear Information System (INIS)

    Mauger, Christopher M.

    2015-01-01

    The NuMI facility at Fermilab is currently providing an extremely intense beam of neutrinos for the NO@@A, MINER@@A and MINOS+ experiments. By installing the 5-ton CAPTAIN liquid argon TPC in front of the MINER@@A detector in the NuMI beamline and combining the data from the CAPTAIN, MINER@@A and MINOS+ detectors, a broad program of few-GeV neutrino cross section measurements on argon can be pursued. These measurements will be extremely helpful for future oscillation experiments. By directly comparing the cross sections on argon to MINER@@A@@@s scintillator (CH) target, a new level of precision can be achieved in the measurements of the effects of the nucleus on neutrino interactions. These effects are of interest to not only the particle physics but also the nuclear physics community. This document describes in detail the physics goals of the CAPTAIN-MINER@@A experiment, in addition to a first estimate of the technical resources required to install, commission and operate the CAPTAIN detector in front of the MINERVA detector.

  1. CAPTAIN-Minerνa. Neutrino-Argon Scattering in a Medium-Energy Neutrino Beam

    Energy Technology Data Exchange (ETDEWEB)

    Mauger, Christopher M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-10-29

    The NuMI facility at Fermilab is currently providing an extremely intense beam of neutrinos for the NOνA, MINERνA and MINOS+ experiments. By installing the 5-ton CAPTAIN liquid argon TPC in front of the MINERνA detector in the NuMI beamline and combining the data from the CAPTAIN, MINERνA and MINOS+ detectors, a broad program of few-GeV neutrino cross section measurements on argon can be pursued. These measurements will be extremely helpful for future oscillation experiments. By directly comparing the cross sections on argon to MINERνA’s scintillator (CH) target, a new level of precision can be achieved in the measurements of the effects of the nucleus on neutrino interactions. These effects are of interest to not only the particle physics but also the nuclear physics community. This document describes in detail the physics goals of the CAPTAIN-MINERνA experiment, in addition to a first estimate of the technical resources required to install, commission and operate the CAPTAIN detector in front of the MINERVA detector.

  2. Patient-specific scatter correction in clinical cone beam computed tomography imaging made possible by the combination of Monte Carlo simulations and a ray tracing algorithm

    International Nuclear Information System (INIS)

    Thing, Rune S.; Bernchou, Uffe; Brink, Carsten; Mainegra-Hing, Ernesto

    2013-01-01

    Purpose: Cone beam computed tomography (CBCT) image quality is limited by scattered photons. Monte Carlo (MC) simulations provide the ability of predicting the patient-specific scatter contamination in clinical CBCT imaging. Lengthy simulations prevent MC-based scatter correction from being fully implemented in a clinical setting. This study investigates the combination of using fast MC simulations to predict scatter distributions with a ray tracing algorithm to allow calibration between simulated and clinical CBCT images. Material and methods: An EGSnrc-based user code (egs c bct), was used to perform MC simulations of an Elekta XVI CBCT imaging system. A 60keV x-ray source was used, and air kerma scored at the detector plane. Several variance reduction techniques (VRTs) were used to increase the scatter calculation efficiency. Three patient phantoms based on CT scans were simulated, namely a brain, a thorax and a pelvis scan. A ray tracing algorithm was used to calculate the detector signal due to primary photons. A total of 288 projections were simulated, one for each thread on the computer cluster used for the investigation. Results: Scatter distributions for the brain, thorax and pelvis scan were simulated within 2 % statistical uncertainty in two hours per scan. Within the same time, the ray tracing algorithm provided the primary signal for each of the projections. Thus, all the data needed for MC-based scatter correction in clinical CBCT imaging was obtained within two hours per patient, using a full simulation of the clinical CBCT geometry. Conclusions: This study shows that use of MC-based scatter corrections in CBCT imaging has a great potential to improve CBCT image quality. By use of powerful VRTs to predict scatter distributions and a ray tracing algorithm to calculate the primary signal, it is possible to obtain the necessary data for patient specific MC scatter correction within two hours per patient

  3. A moving blocker-based strategy for simultaneous megavoltage and kilovoltage scatter correction in cone-beam computed tomography image acquired during volumetric modulated arc therapy

    International Nuclear Information System (INIS)

    Ouyang, Luo; Lee, Huichen Pam; Wang, Jing

    2015-01-01

    Purpose: To evaluate a moving blocker-based approach in estimating and correcting megavoltage (MV) and kilovoltage (kV) scatter contamination in kV cone-beam computed tomography (CBCT) acquired during volumetric modulated arc therapy (VMAT). Methods and materials: During the concurrent CBCT/VMAT acquisition, a physical attenuator (i.e., “blocker”) consisting of equally spaced lead strips was mounted and moved constantly between the CBCT source and patient. Both kV and MV scatter signals were estimated from the blocked region of the imaging panel, and interpolated into the unblocked region. A scatter corrected CBCT was then reconstructed from the unblocked projections after scatter subtraction using an iterative image reconstruction algorithm based on constraint optimization. Experimental studies were performed on a Catphan® phantom and an anthropomorphic pelvis phantom to demonstrate the feasibility of using a moving blocker for kV–MV scatter correction. Results: Scatter induced cupping artifacts were substantially reduced in the moving blocker corrected CBCT images. Quantitatively, the root mean square error of Hounsfield units (HU) in seven density inserts of the Catphan phantom was reduced from 395 to 40. Conclusions: The proposed moving blocker strategy greatly improves the image quality of CBCT acquired with concurrent VMAT by reducing the kV–MV scatter induced HU inaccuracy and cupping artifacts

  4. Quality of Life and Toxicity From Passively Scattered and Spot-Scanning Proton Beam Therapy for Localized Prostate Cancer

    International Nuclear Information System (INIS)

    Pugh, Thomas J.; Munsell, Mark F.; Choi, Seungtaek; Nguyen, Quyhn Nhu; Mathai, Benson; Zhu, X. Ron; Sahoo, Narayan; Gillin, Michael; Johnson, Jennifer L.; Amos, Richard A.; Dong, Lei; Mahmood, Usama; Kuban, Deborah A.; Frank, Steven J.; Hoffman, Karen E.; McGuire, Sean E.; Lee, Andrew K.

    2013-01-01

    Purpose: To report quality of life (QOL)/toxicity in men treated with proton beam therapy for localized prostate cancer and to compare outcomes between passively scattered proton therapy (PSPT) and spot-scanning proton therapy (SSPT). Methods and Materials: Men with localized prostate cancer enrolled on a prospective QOL protocol with a minimum of 2 years' follow-up were reviewed. Comparative groups were defined by technique (PSPT vs SSPT). Patients completed Expanded Prostate Cancer Index Composite questionnaires at baseline and every 3-6 months after proton beam therapy. Clinically meaningful differences in QOL were defined as ≥0.5 × baseline standard deviation. The cumulative incidence of modified Radiation Therapy Oncology Group grade ≥2 gastrointestinal (GI) or genitourinary (GU) toxicity and argon plasma coagulation were determined by the Kaplan-Meier method. Results: A total of 226 men received PSPT, and 65 received SSPT. Both PSPT and SSPT resulted in statistically significant changes in sexual, urinary, and bowel Expanded Prostate Cancer Index Composite summary scores. Only bowel summary, function, and bother resulted in clinically meaningful decrements beyond treatment completion. The decrement in bowel QOL persisted through 24-month follow-up. Cumulative grade ≥2 GU and GI toxicity at 24 months were 13.4% and 9.6%, respectively. There was 1 grade 3 GI toxicity (PSPT group) and no other grade ≥3 GI or GU toxicity. Argon plasma coagulation application was infrequent (PSPT 4.4% vs SSPT 1.5%; P=.21). No statistically significant differences were appreciated between PSPT and SSPT regarding toxicity or QOL. Conclusion: Both PSPT and SSPT confer low rates of grade ≥2 GI or GU toxicity, with preservation of meaningful sexual and urinary QOL at 24 months. A modest, yet clinically meaningful, decrement in bowel QOL was seen throughout follow-up. No toxicity or QOL differences between PSPT and SSPT were identified. Long-term comparative results in a

  5. RBS using {sup 28}Si beams

    Energy Technology Data Exchange (ETDEWEB)

    Ophel, T.R. [Australian National Univ., Canberra, ACT (Australia); Mitchell, I.V. [University of Western Ontario, London, ON (Canada). Dept. of Physics

    1996-12-31

    Measurements of RBS using {sup 28}Si beams have been made to evaluate the enhancement of sensitivity that should obtain from kinematic suppression of silicon substrate scattering. Two detection methods were tried. Aside from a surface barrier detector, a magnetic spectrometer, instrumented with a multi-electrode gas focal plane detector, was used to indicate the resolution attainable with low energy {sup 28}Si ions. The results confirm that kinematically suppressed RBS does provide greatly improved sensitivity. 5 refs., 2 figs.

  6. RBS using {sup 28}Si beams

    Energy Technology Data Exchange (ETDEWEB)

    Ophel, T R [Australian National Univ., Canberra, ACT (Australia); Mitchell, I V [University of Western Ontario, London, ON (Canada). Dept. of Physics

    1997-12-31

    Measurements of RBS using {sup 28}Si beams have been made to evaluate the enhancement of sensitivity that should obtain from kinematic suppression of silicon substrate scattering. Two detection methods were tried. Aside from a surface barrier detector, a magnetic spectrometer, instrumented with a multi-electrode gas focal plane detector, was used to indicate the resolution attainable with low energy {sup 28}Si ions. The results confirm that kinematically suppressed RBS does provide greatly improved sensitivity. 5 refs., 2 figs.

  7. Understanding and eliminating artifact signals from diffusely scattered pump beam in measurements of rough samples by time-domain thermoreflectance (TDTR)

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Bo [Department of Mechanical Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117576 (Singapore); Koh, Yee Kan, E-mail: mpekyk@nus.edu.sg [Department of Mechanical Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117576 (Singapore); Centre of Advanced 2D Materials, National University of Singapore, Singapore 117542 (Singapore)

    2016-06-15

    Time-domain thermoreflectance (TDTR) is a pump-probe technique frequently applied to measure the thermal transport properties of bulk materials, nanostructures, and interfaces. One of the limitations of TDTR is that it can only be employed to samples with a fairly smooth surface. For rough samples, artifact signals are collected when the pump beam in TDTR measurements is diffusely scattered by the rough surface into the photodetector, rendering the TDTR measurements invalid. In this paper, we systemically studied the factors affecting the artifact signals due to the pump beam leaked into the photodetector and thus established the origin of the artifact signals. We find that signals from the leaked pump beam are modulated by the probe beam due to the phase rotation induced in the photodetector by the illumination of the probe beam. As a result of the modulation, artifact signals due to the leaked pump beam are registered in TDTR measurements as the out-of-phase signals. We then developed a simple approach to eliminate the artifact signals due to the leaked pump beam. We verify our leak-pump correction approach by measuring the thermal conductivity of a rough InN sample, when the signals from the leaked pump beam are significant. We also discuss the advantages of our new method over the two-tint approach and its limitations. Our new approach enables measurements of the thermal conductivity of rough samples using TDTR.

  8. Electron volt neutron spectrometers

    International Nuclear Information System (INIS)

    Pietropaolo, A.; Senesi, R.

    2011-01-01

    The advent of pulsed neutron sources has made available intense fluxes of epithermal neutrons (500 meV ≤E≤100 eV ). The possibility to open new investigations on condensed matter with eV neutron scattering techniques, is related to the development of methods, concepts and devices that drive, or are inspired by, emerging studies at this energy scale. Electron volt spectrometers have undergone continuous improvements since the construction of the first prototype instruments, but in the last decade major breakthroughs have been accomplished in terms of resolution and counting statistics, leading, for example, to the direct measurement of the proton 3-D Born–Oppenheimer potential in any material, or to quantitatively probe nuclear quantum effects in hydrogen bonded systems. This paper reports on the most effective methods and concepts for energy analysis and detection, as well as devices for the optimization of electron volt spectrometers for different applications. This is set in the context of the progress made up to date in instrument development. Starting from early stages of development of the technique, particular emphasis will be given to the Vesuvio eV spectrometer at the ISIS neutron source, the first spectrometer where extensive scientific, as well as research and development programmes have been carried out. The potential offered by this type of instrumentation, from single particle excitations to momentum distribution studies, is then put in perspective into the emerging fields of eV spectroscopy applied to cultural heritages and neutron irradiation effects in electronics. - Highlights: ► Neutron spectrometers at eV energies. ► Methods and techniques for eV neutrons counting at spallation sources. ► Scattering, imaging and radiation hardness tests with multi-eV neutrons.

  9. WE-AB-207A-08: BEST IN PHYSICS (IMAGING): Advanced Scatter Correction and Iterative Reconstruction for Improved Cone-Beam CT Imaging On the TrueBeam Radiotherapy Machine

    Energy Technology Data Exchange (ETDEWEB)

    Wang, A; Paysan, P; Brehm, M; Maslowski, A; Lehmann, M; Messmer, P; Munro, P; Yoon, S; Star-Lack, J; Seghers, D [Varian Medical Systems, Palo Alto, CA (United States)

    2016-06-15

    Purpose: To improve CBCT image quality for image-guided radiotherapy by applying advanced reconstruction algorithms to overcome scatter, noise, and artifact limitations Methods: CBCT is used extensively for patient setup in radiotherapy. However, image quality generally falls short of diagnostic CT, limiting soft-tissue based positioning and potential applications such as adaptive radiotherapy. The conventional TrueBeam CBCT reconstructor uses a basic scatter correction and FDK reconstruction, resulting in residual scatter artifacts, suboptimal image noise characteristics, and other artifacts like cone-beam artifacts. We have developed an advanced scatter correction that uses a finite-element solver (AcurosCTS) to model the behavior of photons as they pass (and scatter) through the object. Furthermore, iterative reconstruction is applied to the scatter-corrected projections, enforcing data consistency with statistical weighting and applying an edge-preserving image regularizer to reduce image noise. The combined algorithms have been implemented on a GPU. CBCT projections from clinically operating TrueBeam systems have been used to compare image quality between the conventional and improved reconstruction methods. Planning CT images of the same patients have also been compared. Results: The advanced scatter correction removes shading and inhomogeneity artifacts, reducing the scatter artifact from 99.5 HU to 13.7 HU in a typical pelvis case. Iterative reconstruction provides further benefit by reducing image noise and eliminating streak artifacts, thereby improving soft-tissue visualization. In a clinical head and pelvis CBCT, the noise was reduced by 43% and 48%, respectively, with no change in spatial resolution (assessed visually). Additional benefits include reduction of cone-beam artifacts and reduction of metal artifacts due to intrinsic downweighting of corrupted rays. Conclusion: The combination of an advanced scatter correction with iterative reconstruction

  10. Direct measurement of the energy spectrum of an intense proton beam

    International Nuclear Information System (INIS)

    Leeper, R.J.; Lee, J.R.; Kissel, L.; Johnson, D.J.; Stygar, W.A.; Hebron, D.E.; Roose, L.D.

    1983-01-01

    A time-resolved magnetic spectrometer has been used to measure the energy spectrum of an intense (0.5 TW/cm 2 ) proton beam. A thin (2400 A) gold foil placed at the focus of an ion diode Rutherford scattered protons by 90 0 into the spectrometer, reducing the beam intensity to a level suitable for magnetic analysis. The scattered beam was collimated by two 1 mm diameter apertures separated by 12.3 cm. The collimated protons were deflected in a 12.7 cm diameter, 6.65 Kg samarium-cobalt permanent magnet. The deflected protons were recorded simultaneously on CR-39 and eight 1 mm 2 by 35 μm thick PIN diodes. A Monte Carlo computer code was used to calculate the sensitivity and resolution of the spectrometer. Data taken on Proto-I show a 150 keV to 250 keV wide proton energy spectrum at each instant in time

  11. Method for more accurate transmittance measurements of low-angle scattering samples using an integrating sphere with an entry port beam diffuser

    International Nuclear Information System (INIS)

    Nilsson, Annica M.; Jonsson, Andreas; Jonsson, Jacob C.; Roos, Arne

    2011-01-01

    For most integrating sphere measurements, the difference in light distribution between a specular reference beam and a diffused sample beam can result in significant errors. The problem becomes especially pronounced in integrating spheres that include a port for reflectance or diffuse transmittance measurements. The port is included in many standard spectrophotometers to facilitate a multipurpose instrument, however, absorption around the port edge can result in a detected signal that is too low. The absorption effect is especially apparent for low-angle scattering samples, because a significant portion of the light is scattered directly onto that edge. In this paper, a method for more accurate transmittance measurements of low-angle light-scattering samples is presented. The method uses a standard integrating sphere spectrophotometer, and the problem with increased absorption around the port edge is addressed by introducing a diffuser between the sample and the integrating sphere during both reference and sample scan. This reduces the discrepancy between the two scans and spreads the scattered light over a greater portion of the sphere wall. The problem with multiple reflections between the sample and diffuser is successfully addressed using a correction factor. The method is tested for two patterned glass samples with low-angle scattering and in both cases the transmittance accuracy is significantly improved.

  12. Molecular beam scattering experiments with polar molecules. 1. Differential elastic scattering of H2+NH3 and H2+H2O

    International Nuclear Information System (INIS)

    Bickes, R.W. Jr.; Scoles, G.; Smith, K.M.

    1974-01-01

    Differential elastic scattering cross sections with well resolved quantum oscillations have been measuremed for the systems H 2 +NH 3 and H 2 +H 2 O. Assuming a spherically symmetric interaction the data show that a simple spherical potential (i.e. Lennard-Jones) does not properly describe the scattering

  13. Antiproton-Proton Glory Scattering

    CERN Multimedia

    2002-01-01

    This experiment measures @*p and K|-p backwards scattering between 8 and 16 GeV/c in the Omega spectrometer using the S1 beam, with sensitivities of several events per nanobarn. The mechanism responsible for backward scattering in channels not mediated by particle exchange is not understood, and could be almost energy-independent glory scattering, especially since relatively high cross sections of 190~(@*p) and 120~(K|-p)nb have been measured earlier at 5~GeV/c. @p|-p backwards scattering is measured for monitoring purposes. The trigger requires a forward particle of momentum close to the beam momentum. Absence of light in the two forward Cerenkov counters indicates that the particle is a proton. Combinations of an incident @p|- and an outgoing K|+, or an incident K|- or @* and an outgoing @p|+, cover the following byproducts: @*p~@A~@p|+@p|- which is an (allowed) baryon exchange reaction, and the exotic exchange reactions @p|-p~@A~K|+Y K|-p~@A~@p|+Y|-, where Y|- may be the @S|- or the Y*|-(1385).

  14. Molecular beams

    International Nuclear Information System (INIS)

    Pendelbury, J.M.; Smith, K.F.

    1987-01-01

    Studies with directed collision-free beams of particles continue to play an important role in the development of modern physics and chemistry. The deflections suffered by such beams as they pass through electric and magnetic fields or laser radiation provide some of the most direct information about the individual constituents of the beam; the scattering observed when two beams intersect yields important data about the intermolecular forces responsible for the scattering. (author)

  15. Adsorption of n-butane on graphene/Ru(0001)—A molecular beam scattering study

    Energy Technology Data Exchange (ETDEWEB)

    Sivapragasam, Nilushni; Nayakasinghe, Mindika T.; Burghaus, Uwe, E-mail: uwe.burghaus@ndsu.edu [Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108 (United States)

    2016-07-15

    Adsorption kinetics/dynamics of n-butane on graphene, physical vapor deposited on Ru(0001) (hereafter G/Ru), and bare Ru(0001) (hereafter Ru) are discussed. The chemical activity of the supported-graphene as well as the support was probed by thermal desorption spectroscopy (adsorption kinetics). In addition and to the best of our knowledge, for the first time, molecular beam scattering data of larger molecules were collected for graphene (probing the adsorption dynamics). Furthermore, samples were inspected by x-ray photoelectron spectroscopy and Auger electron spectroscopy. At the measuring conditions used here, n-butane adsorption kinetics/dynamics are molecular and nonactivated. Binding energies of butane on Ru and G/Ru are indistinguishable within experimental uncertainty. Thus, G/Ru is “kinetically transparent.” Initial adsorption probabilities, S{sub 0}, of n-butane decrease with increasing impact energy (0.76–1.72 eV) and are adsorption temperature independent for both Ru and G/Ru, again consistent with molecular adsorption. Also, S{sub 0} of Ru and G/Ru are indistinguishable within experimental uncertainty. Thus, G/Ru is “dynamically transparent.” Coverage dependent adsorption probabilities indicate precursor effects for graphene/Ru.

  16. Inclusive deep inelastic scattering at high Q{sup 2} with longitudinally polarised lepton beams at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Aaron, F.D. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Bucharest Univ. (Romania). Faculty of Physics; Alexa, C. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Andreev, V. [Lebedev Physical Institute, Moscow (RU)] (and others)

    2012-06-15

    Inclusive e{sup {+-}}p single and double differential cross sections for neutral and charged current deep inelastic scattering processes are measured with the H1 detector at HERA. The data were taken at a centre-of-mass energy of {radical}(s)=319 GeV with a total integrated luminosity of 333.7 pb{sup -1} shared between two lepton beam charges and two longitudinal lepton polarisation modes. The differential cross sections are measured in the range of negative four-momentum transfer squared, Q{sup 2}, between 60 and 50000 GeV{sup 2}, and Bjorken x between 0.0008 and 0.65. The measurements are combined with earlier published unpolarised H1 data to improve statistical precision and used to determine the structure function xF{sup {gamma}}{sup Z}{sub 3}. A measurement of the neutral current parity violating structure function F{sup {gamma}}{sup Z}{sub 2} is presented for the first time. The polarisation dependence of the charged current total cross section is also measured. The new measurements are well described by a next-to-leading order QCD fit based on all published H1 inclusive cross section data which are used to extract the parton distribution functions of the proton.

  17. An assessment of the secondary neutron dose in the passive scattering proton beam facility of the national cancer center

    Energy Technology Data Exchange (ETDEWEB)

    Han, Sang Eun [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of); Cho, Gyuseong [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Lee, Se Byeong [Proton Therapy Center, National Cancer Center, Goyang (Korea, Republic of)

    2017-06-15

    The purpose of this study is to assess the additional neutron effective dose during passive scattering proton therapy. Monte Carlo code (Monte Carlo N-Particle 6) simulation was conducted based on a precise modeling of the National Cancer Center's proton therapy facility. A three-dimensional neutron effective dose profile of the interior of the treatment room was acquired via a computer simulation of the 217.8-MeV proton beam. Measurements were taken with a 3He neutron detector to support the simulation results, which were lower than the simulation results by 16% on average. The secondary photon dose was about 0.8% of the neutron dose. The dominant neutron source was deduced based on flux calculation. The secondary neutron effective dose per proton absorbed dose ranged from 4.942 ± 0.031 mSv/Gy at the end of the field to 0.324 ± 0.006 mSv/Gy at 150 cm in axial distance.

  18. Adsorption of n-butane on graphene/Ru(0001)—A molecular beam scattering study

    International Nuclear Information System (INIS)

    Sivapragasam, Nilushni; Nayakasinghe, Mindika T.; Burghaus, Uwe

    2016-01-01

    Adsorption kinetics/dynamics of n-butane on graphene, physical vapor deposited on Ru(0001) (hereafter G/Ru), and bare Ru(0001) (hereafter Ru) are discussed. The chemical activity of the supported-graphene as well as the support was probed by thermal desorption spectroscopy (adsorption kinetics). In addition and to the best of our knowledge, for the first time, molecular beam scattering data of larger molecules were collected for graphene (probing the adsorption dynamics). Furthermore, samples were inspected by x-ray photoelectron spectroscopy and Auger electron spectroscopy. At the measuring conditions used here, n-butane adsorption kinetics/dynamics are molecular and nonactivated. Binding energies of butane on Ru and G/Ru are indistinguishable within experimental uncertainty. Thus, G/Ru is “kinetically transparent.” Initial adsorption probabilities, S 0 , of n-butane decrease with increasing impact energy (0.76–1.72 eV) and are adsorption temperature independent for both Ru and G/Ru, again consistent with molecular adsorption. Also, S 0 of Ru and G/Ru are indistinguishable within experimental uncertainty. Thus, G/Ru is “dynamically transparent.” Coverage dependent adsorption probabilities indicate precursor effects for graphene/Ru.

  19. Resonance Raman scattering of β-carotene solution excited by visible laser beams into second singlet state.

    Science.gov (United States)

    Lu, Luyao; Shi, Lingyan; Secor, Jeff; Alfano, Robert

    2018-02-01

    This study aimed to use self-absorption correction to determine the Raman enhancement of β-carotene. The Raman spectra of β-carotene solutions were measured using 488nm, 514nm, 532nm and 633nm laser beams, which exhibited significant resonance Raman (RR) enhancement when the laser energy approaches the electronic transition energy from S 0 to S 2 state. The Raman intensity and the actual resonance Raman gain without self-absorption from S 2 state by β-carotene were also obtained to evaluate the effect of self-absorption on RR scattering. Moreover, we observed the Raman intensity strength followed the absorption spectra. Our study found that, although 488nm and 514nm pumps seemed better for stronger RR enhancement, 532nm would be the optimum Raman pump laser with moderate RR enhancement due to reduced fluorescence and self-absorption. The 532nm excitation will be helpful for applying resonance Raman spectroscopy to investigate biological molecules in tissues. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. UCN gravitational spectrometer

    International Nuclear Information System (INIS)

    Kawabata, Yuji

    1988-01-01

    Concept design is carried out of two types of ultra cold neutron scallering equipment using the fall-focusing principle. One of the systems comprises a vertical gravitational spectrometer and the other includes a horizontal gravitation analyzer. A study is made of their performance and the following results are obtained. Fall-focusing type ultra cold neutron scattering equipment can achieve a high accuracy for measurement of energy and momentum. Compared with conventional neutron scattering systems, this type of equipment can use neutron very efficiently because scattered neutrons within a larger solid angle can be used. The maximum solid angle is nearly 4π and 2π for the vertical and horizontal type, respectively. Another feature is that the size of equipment can be reduced. In the present concept design, the equipment is spherical with a diameter of about 1 m, as compared with NESSIE which is 6.7 m in length and 4.85 m in height with about the same accuracy. Two horizontal analyzers and a vertical spectroscope are proposed. They are suitable for angle-dependent non-elastic scattering in the neutron velocity range of 6∼15 m/s, pure elastic scattering in the range of 4∼7 m/s, or angle-integration non-elastic scattering in the range of 4∼15 m/s. (N.K.)