International Nuclear Information System (INIS)
Lovesey, S.W.
1987-05-01
The report reviews, at an introductory level, the theory of photon scattering from condensed matter. Magnetic scattering, which arises from first-order relativistic corrections to the Thomson scattering amplitude, is treated in detail and related to the corresponding interaction in the magnetic neutron diffraction amplitude. (author)
Spatial photon correlations in multiple scattering media
DEFF Research Database (Denmark)
Smolka, Stephan; Muskens, O.; Lagendijk, A.
2010-01-01
We present the first angle-resolved measurements of spatial photon correlations that are induced by multiple scattering of light. The correlation relates multiple scattered photons at different spatial positions and depends on incident photon fluctuations.......We present the first angle-resolved measurements of spatial photon correlations that are induced by multiple scattering of light. The correlation relates multiple scattered photons at different spatial positions and depends on incident photon fluctuations....
Delbrueck scattering of monoenergetic photons
International Nuclear Information System (INIS)
Kahane, S.
1978-05-01
The Delbrueck effect was experimentally investigated in high Z nuclei with monoenergetic photons in the range 6.8-11.4 MeV. Two different methods were used for measurements of the differential scattering cross-section, in the 25-140 deg range and in the forward direction (theta = 1.5 deg), respectively. The known Compton scattering cross-section was used in a new and unique way for the determination of the elastic scattering cross-section. Isolation of the contribution of the real Delbrueck amplitudes to the cross-section was crried out successfully. Experimental confirmation of the theoretical calculations of Papatzacos and Mork and measurement, for the first time, of the Rayleigh scattering in the 10 MeV region are also reported. One of the most interesting findings is the presence of Coulomb corrections in Delbrueck scattering at these energies. More theoretical effort is needed in this last direction. (author)
Photons emission processes in electron scattering
International Nuclear Information System (INIS)
Soto Vargas, C.W.
1996-01-01
The investigations involving the scattering sections arising in virtual an real photon emission processes of electron and positron scattering by an atomic nucleus, have the need for thorough and complete calculations of the virtual photon spectrum and then introduce the distorted wave formulation, which is mathematically involved an numerically elaborated, but accessible to its use in experimental electron scattering facilities. (author) [es
What's new in nuclear photon scattering
Energy Technology Data Exchange (ETDEWEB)
Hayward, E. [National Bureau of Standards, Washington, DC (USA); Ikegami, H.; Muraoka, M. [eds.; Osaka Univ., Suita (Japan). Research Center for Nuclear Physics
1980-01-01
Our present understanding of photon scattering is reviewed. The results of new experiments to test the Dynamic Collective Model are summarized. An experimental measurement of the E2 strength in /sup 12/C is described.
Ultrastrong Coupling Few-Photon Scattering Theory
Shi, Tao; Chang, Yue; García-Ripoll, Juan José
2018-04-01
We study the scattering of individual photons by a two-level system ultrastrongly coupled to a waveguide. The scattering is elastic for a broad range of couplings and can be described with an effective U (1 )-symmetric Hamiltonian. This simple model allows the prediction of scattering resonance line shapes, validated up to α =0.3 , and close to the Toulouse point α =1 /2 , where inelastic scattering becomes relevant. Our predictions model experiments with superconducting circuits [P. Forn-Díaz et al., Nat. Phys. 13, 39 (2017), 10.1038/nphys3905] and can be extended to study multiphoton scattering.
Photon-photon inclusive scattering and perturbative QCD
International Nuclear Information System (INIS)
Maor, U.
1988-01-01
Perturbative QCD expectations and problems associated with the study of the photon structure function data are reviewed. An assessment is given for the viability and sensitivity of photon-photon scattering as a decisive tool for the determination of the QCD scale. Particular attention is given to the theoretical problems of singularity cancellations at x = 0 and threshold-associated difficulties at x = 1 and their implications on the actual data analysis. It is concluded that the experimental results, while not providing a decisive verification of QCD at small distances, do add to other independent experiments which are all consistent with the theory and suggest a reasonably well defined QCD scale parameter. The importance of the small Q 2 limit to photon-photon analysis is discussed and the data are examined in an attempt to identify and isolate the contributions of the hadronic and point-like sectors of the target photon. 21 refs., 7 figs. (author)
Scattering of photons from atomic electrons
International Nuclear Information System (INIS)
Pratt, R.H.; Zhou, B.; Bergstrom, P.M. Jr.; Pisk, K.; Suric, T.
1990-01-01
Validity of simpler approaches for elastic and inelastic photon scattering by atoms and ions is assessed by comparison with second-order S-matrix predictions. A simple scheme for elastic scattering based on angle-independent anomalous scattering factors has been found to give useful predictions near and below photoeffect thresholds. In inelastic scattering, major deviations are found from A 2 -based calculations. Extension of free-atom and free-ion cross sections to the dense plasma regime is discussed. 20 refs., 6 figs
Photon scattering by the giant dipole resonance
International Nuclear Information System (INIS)
Bowles, T.J.; Holt, R.J.; Jackson, H.E.; McKeown, R.D.; Specht, J.R.
1979-01-01
Although many features of the giant dipole resonance are well known, the coupling between the basic dipole oscillation and other nuclear collective degrees of freedom such as surface vibrations and rotations is poorly understood. This aspect was investigated by elastic and inelastic bremsstrahlung scattering of tagged photons over the energy range 15 to 22 MeV. Target nuclei were 60 Ni, 52 Cr, 56 Fe, 92 Mo, and 96 Mo. Scattering and absorption cross sections are tabulated, along with parameters obtained from a two-Lorentzian analysis of the scattering cross sections; measured spectra are shown. It was necessary to remove Thomson scattering from the experimental results. It was found that coupling to surface vibrations in the giant dipole resonance is much weaker than the dynamic collective model suggests. The elastic scattering cross section for all targets but 60 Ni showed structure that is not evident in the absorption cross section measurement. 12 figures, 2 tables
Photon diffractive dissociation in deep inelastic scattering
International Nuclear Information System (INIS)
Ryskin, M.G.
1990-01-01
The new ep-collider HERA gives us the possibility to study the diffractive dissociation of virtual photon in deep inelastic ep-collision. The process of photon dissociation in deep inelastic scattering is the most direct way to measure the value of triple-pomeron vertex G 3P . It was shown that the value of the correct bare vertex G 3P may more than 4 times exceeds its effective value measuring in the triple-reggeon region and reaches the value of about 40-50% of the elastic pp-pomeron vertex. On the contrary in deep inelastic processes the perpendicular momenta q t of the secondary particles are large enough. Thus in deep inelastic reactions one can measure the absolute value of G 3P vertex in the most direct way and compare its value and q t dependence with the leading log QCD predictions
Research of synchrotron radiation by virtual photon and compton scattering
International Nuclear Information System (INIS)
Meng Xianzhu
2005-01-01
This paper presents a new theory to explain the synchrotron radiation. When charged particle does circular motion in the accelerator, the magnetic field of the accelerator can be taken as periodic, and equivalent to virtual photon. By Compton scattering of virtual photon and charged particle, the virtual photon can be transformed into photon to radiate out. According to this theory, the formula of photon wavelength in synchrotron radiation is found out, and the calculation results of wavelength is consonant with experimental data. (author)
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.
Experimental study of angular dependence in double photon Compton scattering
International Nuclear Information System (INIS)
Sandhu, B.S.; Dewan, R.; Saddi, M.B.; Singh, B.; Ghumman, B.S.
2000-01-01
The collision differential cross-section and energy of one of the final photons for double photon Compton scattering have been measured as a function of scattering angle θ 1 . The incident photon energy is 0.662 MeV and thin aluminium foils are used as a scatterer. The two simultaneously emitted photons in this higher order process are detected in coincidence using two NaI(Tl) scintillation spectrometers and 30 ns timing electronics. The measured values for energy and collision differential cross-section agree with theory within experimental estimated error. The present data provide information of angular dependence in this higher order process
Estimation of scattered photons using a neural network in SPECT
International Nuclear Information System (INIS)
Hasegawa, Wataru; Ogawa, Koichi
1994-01-01
In single photon emission CT (SPECT), measured projection data involve scattered photons. This causes degradation of spatial resolution and contrast in reconstructed images. The purpose of this study is to estimate the scattered photons, and eliminate them from measured data. To estimate the scattered photons, we used an artificial neural network which consists of five input units, five hidden units, and two output units. The inputs of the network are the ratios of the counts acquired by five narrow energy windows and their sum. The outputs are the ratios of the count of scattered photons and that of primary photons to the total count. The neural network was trained with a back-propagation algorithm using count data obtained by a Monte Carlo simulation. The results of simulation showed improvement of contrast and spatial resolution in reconstructed images. (author)
Inelastic electron photon scattering at moderate four momentum transfers
International Nuclear Information System (INIS)
Berger, C.; Genzel, H.; Grigull, R.; Lackas, W.; Raupach, F.; Klovning, A.; Lillestoel, E.; Skard, J.A.; Ackermann, H.; Buerger, J.
1980-10-01
We present new high statistics data on hadron production in photon photon reactions. The data are analyzed in terms of an electron photon scattering formalism. The dependence of the total cross section on Q 2 , the four momentum transfer squared of the scattered electron, and on the mass W of the hadronic system is investigated. The data are compared to predictions from Vector Dominance and the quark model. (orig.)
Compton scattering of photons from electrons bound in light elements
International Nuclear Information System (INIS)
Bergstrom, P.M. Jr.
1994-01-01
A brief introduction to the topic of Compton scattering from bound electrons is presented. The fundamental nature of this process in understanding quantum phenomena is reviewed. Methods for accurate theoretical evaluation of the Compton scattering cross section are presented. Examples are presented for scattering of several keV photons from helium
Elastic and inelastic photon scattering on the atomic nuclei
International Nuclear Information System (INIS)
Piskarev, I.M.
1982-01-01
Works on investigation of elastic and inelastic scattering of photons on heavy and intermediate nuclei are briefly reviewed. Theoretical problems of nuclear and electron Tompson, Releev and Delbrueck scatterings as well as nuclear resonance scattering are briefly discussed. It is shown that differential cross section of coherent elastic scattering is expressed by means of partial amplitudes of shown processes. Experimental investigations on elastic scattering in the region of threshold energies of photonucleon reactions are described. Problems of theoretical description of elastic scattering in different variants of collective models are considered. Discussed are works, investigating channels of inelastic photon scattering with excitation of nuclear Raman effect. It is noted that to describe channels of inelastic photon scattering it is necessary to use models, that correctly regard the microscopic structure of giant resonance levels to obtain information on the nature of these levels. Investigations of processes of photon elastic and inelastic scattering connected with fundamental characteristics of atomic nucleus, permit to obtain valuable spectroscopic information on high-lying levels of nucleus. Detail investigation of photon scattering in a wide range of energies is necessary [ru
Photon diffractive dissociation in deep inelastic scattering
International Nuclear Information System (INIS)
Wuesthoff, M.
1995-09-01
The cross section of the Photon Diffractive Dissociation in Deep Inelastic Scattering is calculated in the frame work of perturbative QCD. In the triple Regge region the BFKL-approximation is used to evaluate the leading contributions of the corresponding Feynman diagrams with a subsequent resummation in terms of integral equations. These equations are partly solved leading to an effective two to four gluons transition vertex. This exhibits remarkable properties like the total symmetry under the interchange of gluons, the conformal invariance and a simple colour structure. The presence of four interacting gluons in the t-channel does not support the simple triple Pomeron picture with solely a local vertex. A dimensional conservation law is found for zero momentum transfer with the consequence that a direct coupling of the three BFKL-singularities is absent. Another consequence is the dominance of small transverse momenta at the triple Pomeron vertex. Beyond the triple Regge limit a slightly different approach is used in which the diagrams are calculated with leading log(Q 2 ) accuracy. Higher twist contributions are neglected except for the longitudinal part of the cross section which dominates at small invariant masses M in accordance with QCD-predictions and measurements for the exclusive production of vector mesons. For the comparison with the recently measured Photon Diffractive Dissociation-data from H1 and ZEUS a model for the Pomeron is introduced based on the F 2 -data. In the spirit of the k t -factorization theorem this model is inserted in place of the BFKL-Pomeron. Considering the fact that this approach does not contain free parameters the agreement between the theoretical prediction and the data is found to be good. (orig.)
Final-photon polarization in the scattering of photons by high-energy electrons
International Nuclear Information System (INIS)
Choi, J.; Choi, S.Y.; Ie, S.H.; Song, H.S.; Good, R.H. Jr.
1987-01-01
A general method for calculating the polarization of the outgoing photon beam in any reaction is presented. As an example the method is applied to the high-energy photon beam produced in Compton scattering of a laser beam by a high-energy electron beam. The Stokes parameters of the outgoing photon beam, relative to a unit vector normal to the photon momentum and including their dependence on the polarization of incident photon and electron beams, are obtained explicitly. It is expected that this method will be useful, both in photon production reactions and in the subsequent high-energy photon reactions
Systematic study on nuclear resonant scattering
International Nuclear Information System (INIS)
Suarez, A.A.; Freitas, M.L.
1974-01-01
New resonant scattering effect of thermal neutron capture gamma rays from Ti and Fe on Sb, Cu, Se and Ce target were observed. These results together with those published by other authors are summarized and discussed in terms of a possible systematic search for new resonant scattering effects
Raman scattering in condensed media placed in photon traps
Goncharov, A. P.; Gorelik, V. S.; Krawtsow, A. V.
2007-11-01
A new type of resonator cells (photon traps) has been worked out, which ensures the Raman opalescence regime (i.e., the conditions under which the relative Raman scattering intensity at the outlet of the cells increases significantly as compared to the exciting line intensity. The Raman scattering spectra of a number of organic and inorganic compounds placed in photon traps are studied under pulse-periodic excitation by a copper-vapor laser.
Hard scattering and jet physics in connection with real photons
International Nuclear Information System (INIS)
Pretzl, K.P.
1983-01-01
This report contains a summary of the physics discussed in the working groups on (a) jet physics at the SPS in hadron-hadron collisions, (b) hard scattering with incident real photons and (c) large psub(T) prompt photons in hadron-hadron collisions. (orig.)
Photon induced resonant Raman scattering in CdS
International Nuclear Information System (INIS)
Muzart, J.; Lluesma, E.G.; Arguello, C.A.; Leite, R.C.C.
1975-01-01
A novel aspect of resonant Raman scattering is observed in CdS by means of the ratio of Stokes to anti-Stokes intensities. With increasing temperature, as the forbidden band energy approaches a value that is twice the incident photon energy, (from a Nd-Yag-laser) a large enhancement of the above ratio is observed for both the LO and the 2LO phonon Raman intensities. The results indicate a resonance with the scattered photon. Resonance is only observed for high incident photon intensities. A possible explanation for the above observations is that flooding of the crystal with photons of energy hν induces states of energy hν displaced from the electronic bands by mixing of electronic and photon states
The photon structure function and hard scattering in two-photon reactions
International Nuclear Information System (INIS)
Kolanoski, H.
1984-09-01
This report summarizes experimental results obtained by the CELLO, JADE, PLUTO and TASSO collaborations on the following topics: the structure function of the photon; hard scattering and jet production and exclusive hadron pair production. (orig.)
On the influence of resonance photon scattering on atom interference
International Nuclear Information System (INIS)
Bozic, M; Arsenovic, D; Sanz, A S; Davidovic, M
2010-01-01
Here, the influence of resonance photon-atom scattering on the atom interference pattern at the exit of a three-grating Mach-Zehnder interferometer is studied. It is assumed that the scattering process does not destroy the atomic wave function describing the state of the atom before the scattering process takes place, but only induces a certain shift and change of its phase. We find that the visibility of the interference strongly depends on the statistical distribution of transferred momenta to the atom during the photon-atom scattering event. This also explains the experimentally observed (Chapman et al 1995 Phys. Rev. Lett. 75 2783) dependence of the visibility on the ratio d p /λ i =y' 12 (2π/kdλ i ), where y' 12 is the distance between the place where the scattering event occurs and the first grating, k is the wave number of the atomic centre-of-mass motion, d is the grating constant and λ i is the photon wavelength. Furthermore, it is remarkable that photon-atom scattering events happen experimentally within the Fresnel region, i.e. the near-field region, associated with the first grating, which should be taken into account when drawing conclusions about the relevance of 'which-way' information for the interference visibility.
Universal dependence of the total number albedo of photons on the mean number of photon scatterings
Directory of Open Access Journals (Sweden)
Ljubenov Vladan L.
2011-01-01
Full Text Available This paper presents the results of research on photon reflection from plane targets based on Monte Carlo simulations performed by the MCNP code. Five materials (water, concrete, aluminum, iron, and copper are examined in the area of initial photon energies of up to 200 keV. The values of the total number albedo for photons dependent on the initial photon energy or the mean number of photon scatterings are calculated and graphically presented. We have shown that the values of the total number albedo for different target materials, expressed as a function of the mean number of photon scatterings, are in good agreement with each other and can be approximated by simple, universal analytic functions obtained by the least squares method. The accuracy of these analytic appoximations is confirmed by their comparison with the results of PENELOPE and FOTELP Monte Carlo codes.
Strong WW scattering at photon linear colliders
International Nuclear Information System (INIS)
Berger, M.S.
1994-06-01
We investigate the possibility of observing strong interactions of longitudinally polarized weak vector bosons in the process γγ → ZZ at a photon linear collider. We make use of polarization of the photon beams and cuts on the decay products of the Z bosons to enhance the signal relative to the background of transversely polarized ZZ pairs. We find that the background overwhelms the signal unless there are strong resonant effects, as for instance from a technicolor analogue of the hadronic f 2 (1270) meson
Nucleon Compton Scattering with Two Space-Like Photons
International Nuclear Information System (INIS)
Andrei Afanasev; I. Akushevich; N.P. Merenkov
2002-01-01
We calculate two-photon exchange effects for elastic electron-proton scattering at high momentum transfers. The corresponding nucleon Compton amplitude is defined by two space-like virtual photons that appear to have significant virtualities. We make predictions for (a) a single-spin beam asymmetry, and (b) a single-spin target asymmetry or recoil proton polarization caused by an unpolarized electron beam
Photon-photon scattering at the high-intensity frontier
Gies, Holger; Karbstein, Felix; Kohlfürst, Christian; Seegert, Nico
2018-04-01
The tremendous progress in high-intensity laser technology and the establishment of dedicated high-field laboratories in recent years have paved the way towards a first observation of quantum vacuum nonlinearities at the high-intensity frontier. We advocate a particularly prospective scenario, where three synchronized high-intensity laser pulses are brought into collision, giving rise to signal photons, whose frequency and propagation direction differ from the driving laser pulses, thus providing various means to achieve an excellent signal to background separation. Based on the theoretical concept of vacuum emission, we employ an efficient numerical algorithm which allows us to model the collision of focused high-intensity laser pulses in unprecedented detail. We provide accurate predictions for the numbers of signal photons accessible in experiment. Our study is the first to predict the precise angular spread of the signal photons, and paves the way for a first verification of quantum vacuum nonlinearity in a well-controlled laboratory experiment at one of the many high-intensity laser facilities currently coming online.
Compton-scatter tissue densitometry: calculation of single and multiple scatter photon fluences
International Nuclear Information System (INIS)
Battista, J.J.; Bronskill, M.J.
1978-01-01
The accurate measurement of in vivo electron densities by the Compton-scatter method is limited by attenuations and multiple scattering in the patient. Using analytic and Monte Carlo calculation methods, the Clarke tissue density scanner has been modelled for incident monoenergetic photon energies from 300 to 2000 keV and for mean scattering angles of 30 to 130 degrees. For a single detector focussed to a central position in a uniform water phantom (25 x 25 x 25 cm 3 ) it has been demonstrated that: (1) Multiple scatter contamination is an inherent limitation of the Compton-scatter method of densitometry which can be minimised, but not eliminated, by improving the energy resolution of the scattered radiation detector. (2) The choice of the incident photon energy is a compromise between the permissible radiation dose to the patient and the tolerable level of multiple scatter contamination. For a mean scattering angle of 40 degrees, the intrinsic multiple-single scatter ratio decreases from 64 to 35%, and the radiation dose (per measurement) increases from 1.0 to 4.1 rad, as the incident photon energy increases from 300 to 2000 keV. These doses apply to a sampled volume of approximately 0.3 cm 3 and an electron density precision of 0.5%. (3) The forward scatter densitometer configuration is optimum, minimising both the dose and the multiple scatter contamination. For an incident photon energy of 1250 keV, the intrinsic multiple-single scatter ratio reduces from 122 to 27%, and the dose reduces from 14.3 to 1.2 rad, as the mean scattering angle decreases from 130 to 30 degrees. These calculations have been confirmed by experimental measurements. (author)
Markov chain solution of photon multiple scattering through turbid slabs.
Lin, Ying; Northrop, William F; Li, Xuesong
2016-11-14
This work introduces a Markov Chain solution to model photon multiple scattering through turbid slabs via anisotropic scattering process, i.e., Mie scattering. Results show that the proposed Markov Chain model agree with commonly used Monte Carlo simulation for various mediums such as medium with non-uniform phase functions and absorbing medium. The proposed Markov Chain solution method successfully converts the complex multiple scattering problem with practical phase functions into a matrix form and solves transmitted/reflected photon angular distributions by matrix multiplications. Such characteristics would potentially allow practical inversions by matrix manipulation or stochastic algorithms where widely applied stochastic methods such as Monte Carlo simulations usually fail, and thus enable practical diagnostics reconstructions such as medical diagnosis, spray analysis, and atmosphere sciences.
Collision, scattering and absorption differential cross-sections in double-photon Compton scattering
International Nuclear Information System (INIS)
Dewan, R.; Saddi, M.B.; Sandhu, B.S.; Singh, B.; Ghumman, B.S.
2005-01-01
The collision, scattering and absorption differential cross-sections of double-photon Compton scattering are measured experimentally for 0.662 MeV incident gamma photons. Two simultaneously emitted gamma quanta are investigated using a slow-fast coincidence technique having 25 ns resolving time. The coincidence spectra for different energy windows of one of the two final photons are recorded using HPGe detector. The experimental data do not suffer from inherent energy resolution of gamma detector and provide more faithful reproduction of the distribution under the full energy peak of recorded coincidence spectra. The present results are in agreement with the currently acceptable theory of this higher order process
Photon distribution function for stocks wave for stimulated Raman scattering
International Nuclear Information System (INIS)
Man'ko, O.V.; Tcherniega, N.V.
1997-04-01
New time-dependent integrals of motion are found for stimulated Raman scattering. Explicit formula for the photon-number probability distribution as a function of the laser-field intensity and the medium parameters is obtained in terms of Hermite polynomials of two variables. (author). 29 refs
Mechanisms of photon scattering on nucleons at intermediate energies
International Nuclear Information System (INIS)
L'vov, A.I.
1992-01-01
The principal question for studies of photon scattering by nucleons and nuclei is the following: Can photon scattering say something new about the structure of these objects in comparisons with photo- and electroproduction investigations? There is a general reason to believe that it is indeed the case. The Hamiltonian of the electromagnetic interaction has, in general, a piece quadratic in the electromagnetic field (the so-called two-photon seagull) which is seen only in two-photon processes, such as Compton scattering. Although the longitudnal part of this seagull is constrained by the gauge invariance, its transverse part is decoupled from the electromagnetic current and cannot be found in photoabsorption processes. The seagull S μν depends on explicit degrees of freedom included into the Hamiltonian. E.g. the non-relativisitic Schroedinger equation has an effective seagull due to the kinetic energy (p - eA) 2 /2M. Its parent relativistic Dirac equation has no seagull at all but has the same low-energy consequences due to additional degrees of freedom (antiparticles). In low-energy nuclear physics, with explicit meson exchanges and meson clouds (i.e. internal polarizability of the nucleons). By explicitly including the mesons into the Hamiltonian one can remove part of the seagulls. Then the rest of them will be a signal for degrees of freedom invisible in photoabsorption at energies of the considered scale. Some seagulls are related with t-channel exchanges in Compton scattering. The π o -exchange is seen in γp-scattering but has no counterpart in photoproduction off the proton. Thus, a complementary study of one- and two-photon reactions provides a way to look in a region of higher energies where direct studies via photoproduction processes may be hard
Measurement of isolated photon production in deep inelastic ep scattering
Energy Technology Data Exchange (ETDEWEB)
Chekanov, S.; Derrick, M.; Magill, S. [Argonne National Lab., Argonne, IL (US)] (and others)
2009-09-15
Isolated photon production in deep inelastic ep scattering has been measured with the ZEUS detector at HERA using an integrated luminosity of 320 pb{sup -1}. Measurements were made in the isolated-photon transverse-energy and pseudo- rapidity ranges 45 GeV. Differential cross sections are presented for inclusive isolated photon production as functions of Q{sup 2}, x, E{sub T}{sup {gamma}} and {eta}{sup {gamma}}. Leading-logarithm parton-shower Monte Carlo simulations and perturbative QCD predictions give a reasonable description of the data over most of the kinematic range. (orig.)
Hard scattering of (almost) real photons at HERA
International Nuclear Information System (INIS)
Jong, S.J. de; Engelen, J.J.
1988-01-01
High P T photoproduction will play an important role at HERA, both as interesting physics in its own right and as a background. Photoproduction reactions producing large transverse momenta will be reviewed, as well as the possibility of using them for tests of perturbative QCD. Pointlike coupling of the photon to the proton constituents will be considered in detail in leading log approximation. Although the cross sections of these processes, photon gluon fusion and QCD Compton scattering, get their largest contribution from low Q 2 (almost) real photons, we calculate them over the full Q 2 range. Photoproduction as a background to the standard deep inelastic physics at HERA and to exotic phenomena is discussed. Heavy flavour production through photon gluon fusion may offer good possibilities of studying charm and bottom quarks. An attempt is made to determine a possible strategy to identify the top quark at HERA. 29 refs.; 20 figs.; 7 tabs
Compton Scattering of Quasi-Real Virtual Photons at LEP
Achard, P.; Aguilar-Benitez, M.; Alcaraz, J.; Alemanni, G.; Allaby, J.; Aloisio, A.; Alviggi, M.G.; Anderhub, H.; Andreev, Valery P.; Anselmo, F.; Arefiev, A.; Azemoon, T.; Aziz, T.; Bagnaia, P.; Bajo, A.; Baksay, G.; Baksay, L.; Baldew, S.V.; Banerjee, S.; Banerjee, Sw.; Barczyk, A.; Barillere, R.; Bartalini, P.; Basile, M.; Batalova, N.; Battiston, R.; Bay, A.; Becattini, F.; Becker, U.; Behner, F.; Bellucci, L.; Berbeco, R.; Berdugo, J.; Berges, P.; Bertucci, B.; Betev, B.L.; Biasini, M.; Biglietti, M.; Biland, A.; Blaising, J.J.; Blyth, S.C.; Bobbink, G.J.; Bohm, A.; Boldizsar, L.; Borgia, B.; Bottai, S.; Bourilkov, D.; Bourquin, M.; Braccini, S.; Branson, J.G.; Brochu, F.; Burger, J.D.; Burger, W.J.; Cai, X.D.; Capell, M.; Cara Romeo, G.; Carlino, G.; Cartacci, A.; Casaus, J.; Cavallari, F.; Cavallo, N.; Cecchi, C.; Cerrada, M.; Chamizo, M.; Chang, Y.H.; Chemarin, M.; Chen, A.; Chen, G.; Chen, G.M.; Chen, H.F.; Chen, H.S.; Chiefari, G.; Cifarelli, L.; Cindolo, F.; Clare, I.; Clare, R.; Coignet, G.; Colino, N.; Costantini, S.; de la Cruz, B.; Cucciarelli, S.; de Asmundis, R.; Deglon, P.; Debreczeni, J.; Degre, A.; Dehmelt, K.; Deiters, K.; della Volpe, D.; Delmeire, E.; Denes, P.; DeNotaristefani, F.; De Salvo, A.; Diemoz, M.; Dierckxsens, M.; Dionisi, C.; Dittmar, M.; Doria, A.; Dova, M.T.; Duchesneau, D.; Duda, M.; Echenard, B.; Eline, A.; El Hage, A.; El Mamouni, H.; Engler, A.; Eppling, F.J.; Extermann, P.; Falagan, M.A.; Falciano, S.; Favara, A.; Fay, J.; Fedin, O.; Felcini, M.; Ferguson, T.; Fesefeldt, H.; Fiandrini, E.; Field, J.H.; Filthaut, F.; Fisher, P.H.; Fisher, W.; Fisk, I.; Forconi, G.; Freudenreich, K.; Furetta, C.; Galaktionov, Iouri; Ganguli, S.N.; Garcia-Abia, Pablo; Gataullin, M.; Gentile, S.; Giagu, S.; Gong, Z.F.; Grenier, Gerald Jean; Grimm, O.; Gruenewald, M.W.; Guida, M.; Gupta, V.K.; Gurtu, A.; Gutay, L.J.; Haas, D.; Hatzifotiadou, D.; Hebbeker, T.; Herve, Alain; Hirschfelder, J.; Hofer, H.; Hohlmann, M.; Holzner, G.; Hou, S.R.; Jin, B.N.; Jindal, P.; Jones, Lawrence W.; de Jong, P.; Josa-Mutuberria, I.; Kaur, M.; Kienzle-Focacci, M.N.; Kim, J.K.; Kirkby, Jasper; Kittel, W.; Klimentov, A.; Konig, A.C.; Kopal, M.; Koutsenko, V.; Kraber, M.; Kraemer, R.W.; Kruger, A.; Kunin, A.; Ladron de Guevara, P.; Laktineh, I.; Landi, G.; Lebeau, M.; Lebedev, A.; Lebrun, P.; Lecomte, P.; Lecoq, P.; Le Coultre, P.; Le Goff, J.M.; Leiste, R.; Levtchenko, M.; Levtchenko, P.; Li, C.; Likhoded, S.; Lin, C.H.; Lin, W.T.; Linde, F.L.; Lista, L.; Liu, Z.A.; Lohmann, W.; Longo, E.; Lu, Y.S.; Luci, C.; Luminari, L.; Lustermann, W.; Ma, W.G.; Malgeri, L.; Malinin, A.; Mana, C.; Mans, J.; Martin, J.P.; Marzano, F.; Mazumdar, K.; McNeil, R.R.; Mele, S.; Merola, L.; Meschini, M.; Metzger, W.J.; Mihul, A.; Milcent, H.; Mirabelli, G.; Mnich, J.; Mohanty, G.B.; Muanza, G.S.; Muijs, A.J.M.; Musicar, B.; Musy, M.; Nagy, S.; Natale, S.; Napolitano, M.; Nessi-Tedaldi, F.; Newman, H.; Nisati, A.; Novak, T.; Kluge, Hannelies; Ofierzynski, R.; Organtini, G.; Pal, I.; Palomares, C.; Paolucci, P.; Paramatti, R.; Passaleva, G.; Patricelli, S.; Paul, Thomas Cantzon; Pauluzzi, M.; Paus, C.; Pauss, F.; Pedace, M.; Pensotti, S.; Perret-Gallix, D.; Piccolo, D.; Pierella, F.; Pioppi, M.; Piroue, P.A.; Pistolesi, E.; Plyaskin, V.; Pohl, M.; Pojidaev, V.; Pothier, J.; Prokofiev, D.; Rahal-Callot, G.; Rahaman, Mohammad Azizur; Raics, P.; Raja, N.; Ramelli, R.; Rancoita, P.G.; Ranieri, R.; Raspereza, A.; Razis, P.; Ren, D.; Rescigno, M.; Reucroft, S.; Riemann, S.; Riles, Keith; Roe, B.P.; Romero, L.; Rosca, A.; Rosemann, C.; Rosenbleck, C.; Rosier-Lees, S.; Roth, Stefan; Rubio, J.A.; Ruggiero, G.; Rykaczewski, H.; Sakharov, A.; Saremi, S.; Sarkar, S.; Salicio, J.; Sanchez, E.; Schafer, C.; Schegelsky, V.; Schmidt-Kaerst, S.; Schopper, H.; Schotanus, D.J.; Sciacca, C.; Servoli, L.; Shevchenko, S.; Shivarov, N.; Shoutko, V.; Shumilov, E.; Shvorob, A.; Son, D.; Souga, C.; Spillantini, P.; Steuer, M.; Stickland, D.P.; Stoyanov, B.; Straessner, A.; Sudhakar, K.; Sultanov, G.; Sun, L.Z.; Sushkov, S.; Suter, H.; Swain, J.D.; Szillasi, Z.; Tang, X.W.; Tarjan, P.; Tauscher, L.; Taylor, L.; Tellili, B.; Teyssier, D.; Timmermans, Charles; Ting, Samuel C.C.; Ting, S.M.; Tonwar, S.C.; Toth, J.; Tully, C.; Tung, K.L.; Ulbricht, J.; Valente, E.; Van de Walle, R.T.; Vasquez, R.; Veszpremi, V.; Vesztergombi, G.; Vetlitsky, I.; Viertel, G.; Villa, S.; Vivargent, M.; Vlachos, S.; Vodopianov, I.; Vogel, H.; Vogt, H.; Vorobiev, I.; Vorobyov, A.A.; Wadhwa, M.; Wang, Q.; Wang, X.L.; Wang, Z.M.; Weber, M.; Wynhoff, S.; Xia, L.; Xu, Z.Z.; Yamamoto, J.; Yang, B.Z.; Yang, H.J.; Yeh, S.C.; Zalite, An.; Zhang, Z.P.; Zhao, J.; Zhu, G.Y.; Zhu, R.Y.; Zhuang, H.L.; Zichichi, A.; Zimmermann, B.; Zoller, M.
2005-01-01
Compton scattering of quasi-real virtual photons, gamma e+- -> gamma e+-, is studied with 0.6fb-1 of data collected by the L3 detector at the LEP e+e- collider at centre-of-mass energies root(s')=189-209GeV. About 4500 events produced by the interaction of virtual photons emitted by e+- of one beam with e-+ of the opposite beam are collected for effective centre-of-mass energies of the photon-electron and photon-positron systems in the range from root(s')= 35GeV up to root(s')=175GeV, the highest energy at which Compton scattering was ever probed. The cross sections of the gamma e+- -> gamma e+- process as a function of root(s') and of the rest-frame scattering angle are measured, combined with previous L3 measurements down to root(s')~20GeV, and found to agree with the QED expectations.
Effects of multiple scattering and target structure on photon emission
International Nuclear Information System (INIS)
Blankenbecler, R.
1996-05-01
The Landau-Pomeranchuk-Migdal effect is the suppression of Bethe-Heitler radiation caused by multiple scattering in the target medium. The quantum treatment given by S.D. Drell and the author for homogeneous targets of finite thickness will be reviewed. It will then be extended to structured targets. In brief, it is shown that radiators composed of separated plates or of a medium with a spatially varying radiation length can exhibit unexpected structure, even coherence maxima and minima, in their photon spectra. Finally, a functional integral method for performing the averaging implicit in multiple scattering will be briefly discussed and the leading corrections to previous results evaluated
Zhou, L.; Gong, Z. R.; Liu, Y. X.; Sun, C. P.; Nori, F.
2010-03-01
We analyze the coherent transport of a single photon, which propagates in a one-dimensional coupled-resonator waveguide and is scattered by a controllable two-level system located inside one of the resonators of this waveguide. Our approach, which uses discrete coordinates, unifies low and high energy effective theories for single-photon scattering. We show that the controllable two-level system can behave as a quantum switch for the coherent transport of a single photon. This study may inspire new electro-optical single-photon quantum devices. We also suggest an experimental setup based on superconducting transmission line resonators and qubits. References: L. Zhou, Z.R. Gong, Y.X. Liu, C.P. Sun, F. Nori, Controllable scattering of photons inside a one-dimensional resonator waveguide, Phys. Rev. Lett. 101, 100501 (2008). L. Zhou, H. Dong, Y.X. Liu, C.P. Sun, F. Nori, Quantum super-cavity with atomic mirrors, Phys. Rev. A 78, 063827 (2008).
Measurement of isolated photon production in deep inelastic ep scattering
International Nuclear Information System (INIS)
Chekanov, S.; Derrick, M.; Magill, S.
2009-09-01
Isolated photon production in deep inelastic ep scattering has been measured with the ZEUS detector at HERA using an integrated luminosity of 320 pb -1 . Measurements were made in the isolated-photon transverse-energy and pseudo- rapidity ranges 4 T γ γ 2 , in the range 10 2 2 and for invariant masses of the hadronic system W X >5 GeV. Differential cross sections are presented for inclusive isolated photon production as functions of Q 2 , x, E T γ and η γ . Leading-logarithm parton-shower Monte Carlo simulations and perturbative QCD predictions give a reasonable description of the data over most of the kinematic range. (orig.)
Study of Compton broadening due to electron-photon scattering
Directory of Open Access Journals (Sweden)
Srinivasa Rao M.
2010-01-01
Full Text Available We have investigated the effects of Compton broadening due to electron-photon scattering in hot stellar atmospheres. A purely electron-photon scattering media is assumed to have plane parallel geometry with an input radiation field localized on one side of the slab. The method is based on the discrete space theory of radiative transfer for the intensity of emitted radiation. The solution is developed to study the importance of scattering of radiation by free electrons in high temperature stellar atmospheres which produces a brodening and shift in spectral lines because of the Compton effect and the Doppler effect arising from mass and thermal motions of scattering electrons. It is noticed that the Comptonized spectrum depends on three parameters: the optical depth of the medium, the temperature of the thermal electrons and the viewing angle. We also showed that the Compton effect produces red shift and asymmetry in the line. These two effects increase as the optical depth increases. It is also noticed that the emergent specific intensities become completely asymmetric for higher optical depths.
Study of Compton Broadening Due to Electron-Photon Scattering
Directory of Open Access Journals (Sweden)
Srinivasa Rao, M.
2010-06-01
Full Text Available We have investigated the effects of Compton broadening due to electron-photon scattering in hot stellar atmospheres. A purely electron-photon scattering media is assumed to have plane parallel geometry with an input radiation field localized on one side of the slab. The method is based on the discrete space theory of radiative transfer for the intensity of emitted radiation.The solution is developed to study the importance of scattering of radiation by free electrons in high temperature stellar atmospheres which produces a brodening and shift in spectral lines because of the Compton effect and the Doppler effect arising from mass and thermal motions of scattering electrons.It is noticed that the Comptonized spectrum depends on three parameters: the optical depth of the medium, the temperature of the thermal electrons and the viewing angle.We also showed that the Compton effect produces red shift and asymmetry in the line. These two effects increase as the optical depth increases. It is also noticed that the emergent specific intensities become completely asymmetric for higher optical depths.
Energy spectrum of Compton scattering of laser photons on relativistic electrons
International Nuclear Information System (INIS)
Ando, Hiroaki; Yoneda, Yasuharu
1976-01-01
The high energy photons in gamma-ray region are obtainable by the Compton scattering of laser photons on relativistic electrons. But the motion of the electrons in the storage ring is not necessarily uniform. In the study of the uneven effect, the energy distribution of scattered photons is derived from the assumed momentum distribution of incident electrons. It is generally impossible to derive the momentum distribution of incident electrons from the energy spectrum of scattered photons. The additional conditions which make this possible in a special case are considered. A calculational method is examined for deriving the energy spectrum of scattered photons from the assumed momentum distribution of incident electrons. (Mori, K.)
SYNRAD3D photon propagation and scattering simulations
International Nuclear Information System (INIS)
Dugan, G; Sagan, D
2013-01-01
The Bmad software library has been used very successfully at Cornell for modeling relativistic charged particles in storage rings and linacs. Associated with this library are a number of programs used for lattice design and analysis. Recently, as part of the CESRTA program, a new program that uses the Bmad library, called Synrad3D, has been developed to track synchrotron radiation photons generated in storage rings and linacs. The motivation for developing Synrad3D was to estimate the energy and position distribution of photon absorption sites, which are critical inputs to codes which model the growth of electron clouds. Synrad3D includes scattering from the vacuum chamber walls, based on X-ray data from an LBNL database for the smooth-surface reflectivity, and an analytical model for diffuse scattering from a surface with finite roughness. Synrad3D can handle any planar lattice and a wide variety of vacuum chamber profiles. In the following sections, the general approach used in Synrad3D will be described. The models used for the vacuum chamber, for specular reflection, and for diffuse reflection, will be described. Examples of the application to the program to predict the radiation environment in the CESRTA ring will be presented. Comparison of the scattering model with X-ray data from DAΦNE will be given. Finally, an application of the program to predict the radiation environment in the ILC damping ring will be shown
International Nuclear Information System (INIS)
Tereshchenko, Sergei A; Podgaetskii, Vitalii M; Vorob'ev, Nikolai S; Smirnov, A V
1998-01-01
The conditions are identified for simultaneous observation of the peaks of scattered and unscattered (ballistic) photons in a narrow pulsed laser beam crossing a strongly scattering medium. The experimental results are explained on the basis of a nonstationary two-flux model of radiation transport. An analytic expression is given for the contribution of ballistic photons to the transmitted radiation, as a function of the characteristics of the scattering medium. It is shown that the ballistic photon contribution can be increased by the use of high-contrast substances which alter selectively the absorption and scattering coefficients of the medium. (laser applications and other topics in quantum electronics)
Fast sampling algorithm for the simulation of photon Compton scattering
International Nuclear Information System (INIS)
Brusa, D.; Salvat, F.
1996-01-01
A simple algorithm for the simulation of Compton interactions of unpolarized photons is described. The energy and direction of the scattered photon, as well as the active atomic electron shell, are sampled from the double-differential cross section obtained by Ribberfors from the relativistic impulse approximation. The algorithm consistently accounts for Doppler broadening and electron binding effects. Simplifications of Ribberfors' formula, required for efficient random sampling, are discussed. The algorithm involves a combination of inverse transform, composition and rejection methods. A parameterization of the Compton profile is proposed from which the simulation of Compton events can be performed analytically in terms of a few parameters that characterize the target atom, namely shell ionization energies, occupation numbers and maximum values of the one-electron Compton profiles. (orig.)
Jet-Tagged Back-Scattering Photons for Quark Gluon Plasma Tomography
Energy Technology Data Exchange (ETDEWEB)
Fries, Rainer J. [Cyclotron Institute and Department of Physics and Astronomy, Texas A and M University, College Station, TX 77845 (United States); De, Somnath; Srivastava, Dinesh K. [Variable Energy Cyclotron Centre, 1/AF, Bidhan Nagar, Kolkata – 700064 (India)
2013-05-02
Direct photons are important probes for quark gluon plasma created in high energy nuclear collisions. Various sources of direct photons in nuclear collisions are known, each of them endowed with characteristic information about the production process. However, it has been challenging to separate direct photon sources through measurements of single inclusive photon spectra and photon azimuthal asymmetry. Here we explore a method to identify photons created from the back-scattering of high momentum quarks off quark gluon plasma. We show that the correlation of back-scattering photons with a trigger jet leads to a signal that should be measurable at RHIC and LHC.
Greeley, A.; Kurtz, N. T.; Neumann, T.; Cook, W. B.; Markus, T.
2016-12-01
Photon counting laser altimeters such as MABEL (Multiple Altimeter Beam Experimental Lidar) - a single photon counting simulator for ATLAS (Advanced Topographical Laser Altimeter System) - use individual photons with visible wavelengths to measure their range to target surfaces. ATLAS, the sole instrument on NASA's upcoming ICESat-2 mission, will provide scientists a view of Earth's ice sheets, glaciers, and sea ice with unprecedented detail. Precise calibration of these instruments is needed to understand rapidly changing parameters such as sea ice freeboard, and to measure optical properties of surfaces like snow covered ice sheets using subsurface scattered photons. Photons that travel through snow, ice, or water before scattering back to an altimeter receiving system travel farther than photons taking the shortest path between the observatory and the target of interest. These delayed photons produce a negative elevation bias relative to photons scattered directly off these surfaces. We use laboratory measurements of snow surfaces using a flight-tested laser altimeter (MABEL), and Monte Carlo simulations of backscattered photons from snow to estimate elevation biases from subsurface scattered photons. We also use these techniques to demonstrate the ability to retrieve snow surface properties like snow grain size.
DEFF Research Database (Denmark)
Nysteen, Anders; McCutcheon, Dara; Mørk, Jesper
2015-01-01
We analytically treat the scattering of two counterpropagating photons on a two-level emitter embedded in an optical waveguide. We find that the nonlinearity of the emitter can give rise to significant pulse-dependent directional correlations in the scattered photonic state, which could be quanti......We analytically treat the scattering of two counterpropagating photons on a two-level emitter embedded in an optical waveguide. We find that the nonlinearity of the emitter can give rise to significant pulse-dependent directional correlations in the scattered photonic state, which could...
Two-photon exchange in elastic electron-nucleon scattering
International Nuclear Information System (INIS)
Blunden, P.G.; Melnitchouk, W.; Tjon, J.A.
2005-01-01
A detailed study of two-photon exchange in unpolarized and polarized elastic electron-nucleon scattering is presented, taking particular account of nucleon finite size effects. Contributions from nucleon elastic intermediate states are found to have a strong angular dependence, which leads to a partial resolution of the discrepancy between the Rosenbluth and polarization transfer measurements of the proton electric to magnetic form factor ratio, G E /G M . The two-photon exchange contribution to the longitudinal polarization transfer P L is small, whereas the contribution to the transverse polarization transfer P T is enhanced at backward angles by several percent, increasing with Q 2 . This gives rise to a small, E /G M obtained from the polarization transfer ratio P T /P L at large Q 2 . We also compare the two-photon exchange effects with data on the ratio of e + p to e - p cross sections, which is predicted to be enhanced at backward angles. Finally, we evaluate the corrections to the form factors of the neutron and estimate the elastic intermediate state contribution to the 3 He form factors
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.)
Heralded entangling quantum gate via cavity-assisted photon scattering
Borges, Halyne S.; Rossatto, Daniel Z.; Luiz, Fabrício S.; Villas-Boas, Celso J.
2018-01-01
We theoretically investigate the generation of heralded entanglement between two identical atoms via cavity-assisted photon scattering in two different configurations, namely, either both atoms confined in the same cavity or trapped into locally separated ones. Our protocols are given by a very simple and elegant single-step process, the key mechanism of which is a controlled-phase-flip gate implemented by impinging a single photon on single-sided cavities. In particular, when the atoms are localized in remote cavities, we introduce a single-step parallel quantum circuit instead of the serial process extensively adopted in the literature. We also show that such parallel circuit can be straightforwardly applied to entangle two macroscopic clouds of atoms. Both protocols proposed here predict a high entanglement degree with a success probability close to unity for state-of-the-art parameters. Among other applications, our proposal and its extension to multiple atom-cavity systems step toward a suitable route for quantum networking, in particular for quantum state transfer, quantum teleportation, and nonlocal quantum memory.
International Nuclear Information System (INIS)
Singh, Manpreet; Singh, Gurvinderjit; Singh, Bhajan; Sandhu, B.S.
2008-01-01
The gamma photons continue to soften in energy as the number of scatterings increases in the target having finite dimensions both in depth and lateral dimensions. The number of multiply scattered photons increases with an increase in target thickness, and saturates at a particular value of the target thickness known as saturation thickness (depth). The present measurements are carried out to study the energy dependence of saturation thickness of multiply scattered gamma photons from targets of various thicknesses. The scattered photons are detected by a properly shielded NaI(Tl) gamma ray detector placed at 90 deg. to the incident beam. We observe that the saturation thickness increases with increasing incident gamma photon energy. Monte Carlo calculations based upon the package developed by Bauer and Pattison [Compton scattering experiments at the HMI (1981), HMI-B 364, pp. 1-106] support the present experimental results
Review of two-photon exchange in electron scattering
Energy Technology Data Exchange (ETDEWEB)
J. Arrington, P. G. Blunden, W. Melnitchouk
2011-10-01
We review the role of two-photon exchange (TPE) in electron-hadron scattering, focusing in particular on hadronic frameworks suitable for describing the low and moderate Q^2 region relevant to most experimental studies. We discuss the effects of TPE on the extraction of nucleon form factors and their role in the resolution of the proton electric to magnetic form factor ratio puzzle. The implications of TPE on various other observables, including neutron form factors, electroproduction of resonances and pions, and nuclear form factors, are summarized. Measurements seeking to directly identify TPE effects, such as through the angular dependence of polarization measurements, nonlinear epsilon contributions to the cross sections, and via e+p to e-p cross section ratios, are also outlined. In the weak sector, we describe the role of TPE and gamma-Z interference in parity-violating electron scattering, and assess their impact on the extraction of the strange form factors of the nucleon and the weak charge of the proton.
Atomic form factors, incoherent scattering functions, and photon scattering cross sections
International Nuclear Information System (INIS)
Hubbell, J.H.; Veigele, W.J.; Briggs, E.A.; Brown, R.T.; Cromer, D.T.; Howerton, R.J.
1975-01-01
Tabulations are presented of the atomic form factor, F (α,Z), and the incoherent scattering function, S (x,Z), for values of x (=sin theta/2)/lambda) from 0.005 A -1 to 10 9 A -1 , for all elements A=1 to 100. These tables are constructed from available state-of-the-art theoretical data, including the Pirenne formulas for Z=1, configuration-into action results by Brown using Brown-Fontana and Weiss correlated wavefunctions for Z=2 to 6 non-relativistic Hartree-Fock results by Cromer for Z=7 to 100 and a relativistic K-shell analytic expression for F (x,Z) by Bethe Levinger for x>10 A -1 for all elements Z=2 to 100. These tabulated values are graphically compared with available photon scattering angular distribution measurements. Tables of coherent (Rayleigh) and incoherent (Compton) total scattering cross sections obtained by nummerical integration over combinations of F 2 (x,Z) with the Thomson formula and S (x,Z) with the Klum-Nishina Formual, respectively, are presented for all elements Z=1 to 100, for photon energies 100 eV (lambda=124 A) to 100 MeV (0.000124 A). The incoherent scattering cross sections also include the radiative and double-Compton corrections as given by Mork. Similar tables are presented for the special cases of terminally-bonded hydrogen and for the H 2 molecule, interpolated and extrapolated from values calculated by Stewart et al., and by Bentley and Stewart using Kolos-Roothaan wavefunctions
Search for photon–photon elastic scattering in the X-ray region
International Nuclear Information System (INIS)
Inada, T.; Yamaji, T.; Adachi, S.; Namba, T.; Asai, S.; Kobayashi, T.; Tamasaku, K.; Tanaka, Y.; Inubushi, Y.; Sawada, K.; Yabashi, M.; Ishikawa, T.
2014-01-01
We report the first results of a search for real photon–photon scattering using X rays. A novel system is developed to split and collide X-ray pulses by applying interferometric techniques. A total of 6.5×10 5 pulses (each containing about 10 11 photons) from an X-ray Free-Electron Laser are injected into the system. No scattered events are observed, and an upper limit of 1.7×10 −24 m 2 (95% C.L.) is obtained on the photon–photon elastic scattering cross section at 6.5 keV
Controllable scattering of photons in a one-dimensional resonator waveguide
Sun, C. P.; Zhou, L.; Gong, Z. R.; Liu, Y. X.; Nori, F.
2009-03-01
We analyze the coherent transport of a single photon, which propagates in a one-dimensional coupled-resonator waveguide and is scattered by a controllable two-level system located inside one of the resonators of this waveguide. Our approach, which uses discrete coordinates, unifies low and high energy effective theories for single-photon scattering. We show that the controllable two-level system can behave as a quantum switch for the coherent transport of a single photon. This study may inspire new electro-optical single-photon quantum devices. We also suggest an experimental setup based on superconducting transmission line resonators and qubits. [4pt] L. Zhou, Z.R. Gong, Y.X. Liu, C.P. Sun, F. Nori, Controllable scattering of photons in a 1D resonator waveguide, Phys. Rev. Lett. 101, 100501 (2008). URL: http://link.aps.org/abstract/PRL/v101/e100501
Neutron and photon (light) scattering on solitons in the quasi-one-dimensional magnetics
Abdulloev, K O
1999-01-01
The general expression we have found earlier for the dynamics form-factor is used to analyse experiments on the neutron and photon (light) scattering by the gas of solitons in quasi-one-dimensional magnetics (Authors)
Energy Technology Data Exchange (ETDEWEB)
Sun, Hongwei; Pistorius, Stephen [Department of Physics and Astronomy, University of Manitoba, CancerCare, Manitoba (Canada)
2016-08-15
PET images are affected by the presence of scattered photons. Incorrect scatter-correction may cause artifacts, particularly in 3D PET systems. Current scatter reconstruction methods do not distinguish between single and higher order scattered photons. A dual-scattered reconstruction method (GDS-MLEM) that is independent of the number of Compton scattering interactions and less sensitive to the need for high energy resolution detectors, is proposed. To avoid overcorrecting for scattered coincidences, the attenuation coefficient was calculated by integrating the differential Klein-Nishina cross-section over a restricted energy range, accounting only for scattered photons that were not detected. The optimum image can be selected by choosing an energy threshold which is the upper energy limit for the calculation of the cross-section and the lower limit for scattered photons in the reconstruction. Data was simulated using the GATE platform. 500,000 multiple scattered photon coincidences with perfect energy resolution were reconstructed using various methods. The GDS-MLEM algorithm had the highest confidence (98%) in locating the annihilation position and was capable of reconstructing the two largest hot regions. 100,000 photon coincidences, with a scatter fraction of 40%, were used to test the energy resolution dependence of different algorithms. With a 350–650 keV energy window and the restricted attenuation correction model, the GDS-MLEM algorithm was able to improve contrast recovery and reduce the noise by 7.56%–13.24% and 12.4%–24.03%, respectively. This approach is less sensitive to the energy resolution and shows promise if detector energy resolutions of 12% can be achieved.
Photon scattering from a system of multilevel quantum emitters. I. Formalism
Das, Sumanta; Elfving, Vincent E.; Reiter, Florentin; Sørensen, Anders S.
2018-04-01
We introduce a formalism to solve the problem of photon scattering from a system of multilevel quantum emitters. Our approach provides a direct solution of the scattering dynamics. As such the formalism gives the scattered fields' amplitudes in the limit of a weak incident intensity. Our formalism is equipped to treat both multiemitter and multilevel emitter systems, and is applicable to a plethora of photon-scattering problems, including conditional state preparation by photodetection. In this paper, we develop the general formalism for an arbitrary geometry. In the following paper (part II) S. Das et al. [Phys. Rev. A 97, 043838 (2018), 10.1103/PhysRevA.97.043838], we reduce the general photon-scattering formalism to a form that is applicable to one-dimensional waveguides and show its applicability by considering explicit examples with various emitter configurations.
Spin and orbital magnetisation densities determined by Compton scattering of photons
International Nuclear Information System (INIS)
Collins, S.P.; Laundy, D.; Cooper, M.J.; Lovesey, S.W.; Uppsala Univ.
1990-03-01
Compton scattering of a circularly polarized photon beam is shown to provide direct information on orbital and spin magnetisation densities. Experiments are reported which demonstrate the feasibility of the method by correctly predicting the ratio of spin and orbital magnetisation components in iron and cobalt. A partially polarised beam of 45 keV photons from the Daresbury Synchrotron Radiation Source produces charge-magnetic interference scattering which is measured by a field-difference method. Theory shows that the interference cross section contains the Compton profile of polarised electrons modulated by a structure factor which is a weighted sum of spin and orbital magnetisations. In particular, the scattering geometry for which the structure factor vanishes yields a unique value for the ratio of the magnetisation densities. Compton scattering, being an incoherent process, provides data on total unit cell magnetisations which can be directly compared with bulk data. In this respect, Compton scattering complements magnetic neutron and photon Bragg diffraction. (author)
Elastic scattering of virtual photons via a quark loop in the double-logarithmic approximation
Ermolaev, B. I.; Ivanov, D. Yu.; Troyan, S. I.
2018-04-01
We calculate the amplitude of elastic photon-photon scattering via a single quark loop in the double-logarithmic approximation, presuming all external photons to be off-shell and unpolarized. At the same time we account for the running coupling effects. We consider this process in the forward kinematics at arbitrary relations between t and the external photon virtualities. We obtain explicit expressions for the photon-photon scattering amplitudes in all double-logarithmic kinematic regions. Then we calculate the small-x asymptotics of the obtained amplitudes and compare them with the parent amplitudes, thereby fixing the applicability regions of the asymptotics, i.e., fixing the applicability region for the nonvacuum Reggeons. We find that these Reggeons should be used at x <10-8 only.
Relativistic theory of particles in a scattering flow III: photon transport.
Achterberg, A.; Norman, C. A.
2018-06-01
We use the theory developed in Achterberg & Norman (2018a) and Achterberg & Norman (2018b) to calculate the stress due to photons that are scattered elastically by a relativistic flow. We show that the energy-momentum tensor of the radiation takes the form proposed by Eckart (1940). In particular we show that no terms associated with a bulk viscosity appear if one makes the diffusion approximation for radiation transport and treats the radiation as a separate fluid. We find only shear (dynamic) viscosity terms and heat flow terms in our expression for the energy-momentum tensor. This conclusion holds quite generally for different forms of scattering: Krook-type integral scattering, diffusive (Fokker-Planck) scattering and Thomson scattering. We also derive the transport equation in the diffusion approximation that shows the effects of the flow on the photon gas in the form of a combination of adiabatic heating and an irreversible heating term. We find no diffusive changes to the comoving number density and energy density of the scattered photons, in contrast with some published results in Radiation Hydrodynamics. It is demonstrated that these diffusive corrections to the number- and energy density of the photons are in fact higher-order terms that can (and should) be neglected in the diffusion approximation. Our approach eliminates these terms at the root of the expansion that yields the anisotropic terms in the phase-space density of particles and photons, the terms responsible for the photon viscosity.
Demonstration of a novel technique to measure two-photon exchange effects in elastic e±p scattering
Moteabbed, M.; Niroula, M.; Raue, B. A.; Weinstein, L. B.; Adikaram, D.; Arrington, J.; Brooks, W. K.; Lachniet, J.; Rimal, Dipak; Ungaro, M.; Afanasev, A.; Adhikari, K. P.; Aghasyan, M.; Amaryan, M. J.; Anefalos Pereira, S.; Avakian, H.; Ball, J.; Baltzell, N. A.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Bennett, R. P.; Biselli, A. S.; Bono, J.; Boiarinov, S.; Briscoe, W. J.; Burkert, V. D.; Carman, D. S.; Celentano, A.; Chandavar, S.; Cole, P. L.; Collins, P.; Contalbrigo, M.; Cortes, O.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Doughty, D.; Dupre, R.; Egiyan, H.; Fassi, L. El; Eugenio, P.; Fedotov, G.; Fegan, S.; Fersch, R.; Fleming, J. A.; Gevorgyan, N.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Gohn, W.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guler, N.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Harrison, N.; Heddle, D.; Hicks, K.; Ho, D.; Holtrop, M.; Hyde, C. E.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jo, H. S.; Joo, K.; Keller, D.; Khandaker, M.; Kim, A.; Klein, F. J.; Koirala, S.; Kubarovsky, A.; Kubarovsky, V.; Kuhn, S. E.; Kuleshov, S. V.; Lewis, S.; Lu, H. Y.; MacCormick, M.; MacGregor, I. J. D.; Martinez, D.; Mayer, M.; McKinnon, B.; Mineeva, T.; Mirazita, M.; Mokeev, V.; Montgomery, R. A.; Moriya, K.; Moutarde, H.; Munevar, E.; Munoz Camacho, C.; Nadel-Turonski, P.; Nasseripour, R.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Osipenko, M.; Ostrovidov, A. I.; Pappalardo, L. L.; Paremuzyan, R.; Park, K.; Park, S.; Phelps, E.; Phillips, J. J.; Pisano, S.; Pogorelko, O.; Pozdniakov, S.; Price, J. W.; Procureur, S.; Protopopescu, D.; Puckett, A. J. R.; Ripani, M.; Rosner, G.; Rossi, P.; Sabatié, F.; Saini, M. S.; Salgado, C.; Schott, D.; Schumacher, R. A.; Seder, E.; Seraydaryan, H.; Sharabian, Y. G.; Smith, E. S.; Smith, G. D.; Sober, D. I.; Sokhan, D.; Stepanyan, S.; Strauch, S.; Tang, W.; Taylor, C. E.; Tian, Ye; Tkachenko, S.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Wood, M. H.; Zachariou, N.; Zana, L.; Zhang, J.; Zhao, Z. W.; Zonta, I.
2013-08-01
Background: The discrepancy between proton electromagnetic form factors extracted using unpolarized and polarized scattering data is believed to be a consequence of two-photon exchange (TPE) effects. However, the calculations of TPE corrections have significant model dependence, and there is limited direct experimental evidence for such corrections.Purpose: The TPE contributions depend on the sign of the lepton charge in e±p scattering, but the luminosities of secondary positron beams limited past measurement at large scattering angles, where the TPE effects are believe to be most significant. We present the results of a new experimental technique for making direct e±p comparisons, which has the potential to make precise measurements over a broad range in Q2 and scattering angles.Methods: We use the Jefferson Laboratory electron beam and the Hall B photon tagger to generate a clean but untagged photon beam. The photon beam impinges on a converter foil to generate a mixed beam of electrons, positrons, and photons. A chicane is used to separate and recombine the electron and positron beams while the photon beam is stopped by a photon blocker. This provides a combined electron and positron beam, with energies from 0.5 to 3.2 GeV, which impinges on a liquid hydrogen target. The large acceptance CLAS detector is used to identify and reconstruct elastic scattering events, determining both the initial lepton energy and the sign of the scattered lepton.Results: The data were collected in two days with a primary electron beam energy of only 3.3 GeV, limiting the data from this run to smaller values of Q2 and scattering angle. Nonetheless, this measurement yields a data sample for e±p with statistics comparable to those of the best previous measurements. We have shown that we can cleanly identify elastic scattering events and correct for the difference in acceptance for electron and positron scattering. Because we ran with only one polarity for the chicane, we are unable
Energy Technology Data Exchange (ETDEWEB)
Curry, J J, E-mail: jjcurry@nist.go [National Institute of Standards and Technology, Gaithersburg, MD 20899-8422 (United States)
2010-06-16
Coherent and incoherent scattering of x-rays during x-ray absorption imaging of high-intensity discharge lamps have been studied with Monte Carlo simulations developed specifically for this purpose. The Monte Carlo code is described and some initial results are discussed. Coherent scattering, because of its angular concentration in the forward direction, is found to be the most significant scattering mechanism. Incoherent scattering, although comparably strong, is not as significant because it results primarily in photons being scattered in the rearward direction and therefore out of the detector. Coherent scattering interferes with the detected absorption signal because the path of a scattered photon through the object to be imaged is unknown. Although scattering is usually a small effect, it can be significant in regions of high contrast. At the discharge/wall interface, as many as 50% of the detected photons are scattered photons. The effect of scattering on analysis of Hg distributions has not yet been quantified.
Virtual-pion and two-photon production in pp scattering
International Nuclear Information System (INIS)
Scholten, O.; Korchin, A.Yu.
2002-01-01
Two-photon production in pp scattering is proposed as a means of studying virtual-pion emission. Such a process is complementary to real-pion emission in pp scattering. The virtual-pion signal is embedded in a background of double-photon bremsstrahlung. We have developed a model to describe this background process and show that in certain parts of phase space the virtual-pion signal gives significant contributions. In addition, through interference with the two-photon bremsstrahlung background, one can determine the relative phase of the virtual-pion process
Density of states calculations and multiple-scattering theory for photons
International Nuclear Information System (INIS)
Moroz, A.
1994-05-01
The density of states for a finite or an infinite cluster of scatterers in the case of both, electrons and photons, can be represented in a general form as the sum over all Krein-Friedel contributions of individual scatterers and a contribution due to the presence of multiple scatterers. The latter is given by the sum over all periodic orbits between different scatterers. General three dimensional multiple-scattering theory for electromagnetic waves in the presence of scatterers of arbitrary shape is presented. Vector structure constants are calculated and general rules for obtaining them from known scalar structure constants are given. The KKR equations for photons are explicitly written down. (author). 22 refs., 2 figs
Systematics of meson-Skyrmion scattering
International Nuclear Information System (INIS)
Mattis, M.P.
1986-02-01
The S-matrix characterizing the scattering of pions from nucleons is calculated in the context of skyrmion models of the nucleon. These are models in which the nucleon is considered a soliton in the field of pions. The spectrum of nucleon and delta resonances in the Skyrme model is calculated and found to be in overall good agreement with Nature. Model-independent sum rules between amplitudes in the same partial wave are derived and examined. An extension of the formalism to the case of three light flavors is presented. 31 refs., 26 figs., 6 tabs
Systematics of meson-Skyrmion scattering
Energy Technology Data Exchange (ETDEWEB)
Mattis, M.P.
1986-02-01
The S-matrix characterizing the scattering of pions from nucleons is calculated in the context of skyrmion models of the nucleon. These are models in which the nucleon is considered a soliton in the field of pions. The spectrum of nucleon and delta resonances in the Skyrme model is calculated and found to be in overall good agreement with Nature. Model-independent sum rules between amplitudes in the same partial wave are derived and examined. An extension of the formalism to the case of three light flavors is presented. 31 refs., 26 figs., 6 tabs.
Photon nuclear scattering on lead and bismuth in the region of the giant resonance
International Nuclear Information System (INIS)
Tamas, Gabriel.
1976-01-01
The results of monochromatic photon nuclear scattering studies on natural lead and bismuth targets are presented. The cross sections for the inelastic scattering leading to the first excited levels of 204 Pb, 206 Pb and 207 Pb are important, in agreement with theoretical predictions. The elastic scattering amplitude is related to the total photon absorption by dispersion relations. It is then possible to determine the spin of resonances excited by the reaction studied. Precise measurements carried out between 14 and 20MeV revealed that the angular distribution cannot be explained by a single dipolar resonance. A quadrupolar resonance at E 2 =14MeV must be introduced [fr
Raman scattering enhancement in photon-plasmon resonance mediated metal-dielectric microcavity
International Nuclear Information System (INIS)
Guddala, Sriram; Narayana Rao, D.; Dwivedi, Vindesh K.; Vijaya Prakash, G.
2013-01-01
Here, we report the photon-plasmon interaction scheme and enhanced field strengths resulted into the amplification of phonon in a novel microcavity. A metal-dielectric microcavity, with unified cavity photonic mode and localized surface plasmon resonances, is visualized by impregnating the gold nanoparticles into the deep see-through nano-sized pores of porous silicon microcavity. The intense optical field strengths resulting from the photon-plasmon interactions are probed by both resonant and non-resonant Raman scattering experiments. Due to photon-plasmon-phonon interaction mechanism, several orders of enhancement in the intensity of scattered Raman Stokes photon (at 500 cm −1 ) are observed. Our metal nanoparticle-microcavity hybrid system shows the potential to improve the sensing figure of merit as well as the applications of plasmonics for optoelectronics, photovoltaics, and related technologies
First experimental observation of double-photon Compton scattering using single gamma detector
International Nuclear Information System (INIS)
Sandhu, B.S.; Saddi, M.B.; Singh, B.; Ghumman, B.S.
2003-01-01
Full text: The phenomenon of double-photon Compton scattering has been successfully observed using single gamma detector, a technique avoiding the use of complicated slow-fast coincidence set-up used till now for observing this higher order process. Here doubly differentiated collision cross-section integrated over direction of one of the two final photons, the direction of other one being kept fixed, has been measured experimentally for 0.662 MeV incident gamma photons. The energy spectra of the detected photons are observed as a long tail to the single-photon Compton line on the lower side of the full energy peak in the recorded scattered energy spectrum. The present results are in agreement with theory of this process
Realizing total reciprocity violation in the phase for photon scattering.
Deák, László; Bottyán, László; Fülöp, Tamás; Merkel, Dániel Géza; Nagy, Dénes Lajos; Sajti, Szilárd; Schulze, Kai Sven; Spiering, Hartmut; Uschmann, Ingo; Wille, Hans-Christian
2017-02-22
Reciprocity is when wave or quantum scattering satisfies a symmetry property, connecting a scattering process with the reversed one. While reciprocity involves the interchange of source and detector, it is fundamentally different from rotational invariance, and is a generalization of time reversal invariance, occurring in absorptive media as well. Due to its presence at diverse areas of physics, it admits a wide variety of applications. For polarization dependent scatterings, reciprocity is often violated, but violation in the phase of the scattering amplitude is much harder to experimentally observe than violation in magnitude. Enabled by the advantageous properties of nuclear resonance scattering of synchrotron radiation, we have measured maximal, i.e., 180-degree, reciprocity violation in the phase. For accessing phase information, we introduced a new version of stroboscopic detection. The scattering setting was devised based on a generalized reciprocity theorem that opens the way to construct new types of reciprocity related devices.
Jet-Tagged Back-Scattering Photons For Quark Gluon Plasma Tomography
Energy Technology Data Exchange (ETDEWEB)
Fries, Rainer J., E-mail: rjfries@comp.tamu.edu [Cyclotron Institute and Department of Physics and Astronomy, Texas A and M University, College Station, TX 77845 (United States); De, S. [Cyclotron Institute and Department of Physics and Astronomy, Texas A and M University, College Station, TX 77845 (United States); Variable Energy Cyclotron Centre, 1/AF, Bidhan Nagar, Kolkata - 700064 (India); Srivastava, D.K. [Variable Energy Cyclotron Centre, 1/AF, Bidhan Nagar, Kolkata - 700064 (India)
2013-08-15
Several sources of direct photons are known to contribute to the total photon yield in high energy nuclear collisions. All of these photons carry characteristic and important information on the initial nuclei or the hot and dense fireball created in the collision. We investigate the possibility to separate photons from back-scattering of high momentum quarks off quark gluon plasma from other sources. Their unique kinematics can be utilized through high energy jet triggers on the away-side. We discuss the basic idea and estimate the feasibility of such a measurement at RHIC and LHC.
Investigating the effect and photon scattering correction in isotopic scanning with gamma and SPECT
International Nuclear Information System (INIS)
Movafeghi, Amir
1997-01-01
Nowdays medical imaging systems has been become a very important tool in medicine, both in diagnosis and treatment. With the fast improvement in the computer sciences in the last three decades, three dimensional imaging systems or topographic systems has been developed for the daily applications. Among the different methods, for now X-ray Computerized tomography scanning, Magnetic Resonance Imaging, Single Photon Emission Computerized Tomography and Positron Emission tomography have been found many clinical application. SPECT and PET imaging systems are working with the use of emitting photons from special radioisotopes. In these two systems, image is reconstructed from a distribution of radioisotope in the human body's organs. In SPECT accuracy of data quantification for image reconstruction has influenced from photon attenuation, photon scattering, statistical noises and variation in detector response due to distance. Except scattering other three factors could be modeled and compensated with relatively simple models. Photon scattering is a complex process and usually semiemperical methods is used for its modeling. The effect of scattering photons on images was considered. This survey was done in both lab and clinical cases. Radioisotopes were 192 Ir and 99m Tc. 192 Ir is a solid source with the half-life of 73 days and is used at industrial radiography application. At the beginning, models and methods, were established by the help of 192 Ir. Then at the final stage, they were developed to use for 99m Tc. There are different methods for the error correction of scattered photons. A method from the 'window subtraction' group has been developed for lab cases. Generally, in this method with the use of adjacent window of the photopeak window, scattered photons are subtracted from the original count. A Monte Carlo simulation is used for better evaluation of results. In the clinical section , a dual head SPECT system was (ADAC system of Shariati hospital at Tehran). The
Transition radiation and coherent electron-photon scattering
International Nuclear Information System (INIS)
Moran, M.J.
1985-04-01
Relativistic electron irradiation of thin solid targets is known to generate collimated beams of x-ray photons in the forward direction by a number of different processes. A variety of mechanisms are discussed that share common characteristics in the angular and spectral distributions of the generated photon beams. Some simple physical explanations are offered for the characteristics shared by these processes. Some examples are then given based on experimental results attained at the LLNL electron-positron accelerator
Inelastic scattering of neutrons by laser photons and excitons in crystals
International Nuclear Information System (INIS)
Agranovich, V.M.; Lalov, I.J.
1975-01-01
The cross section for the neutron scattering by photons sharply increases in crystals. In view of the fact that a propagating photon in a crystal (polariton), being the superposition of transverse photons and Coulomb excitations (optical phonons, excitons, etc.), involves in the motion also a nucleus subsystem, the cross section for the neutron scattering on the photon turns out to be proportional to the cross section for neutron scattering on nuclei and to the strength function of phonons at the polariton frequency. Numerical estimates for the cross section of the noncoherent photon absorption by a neutron in the case of a LiH crystal in the presence of an intense, electromagnetic radiation point to the possibility of an action of neutron fluxes by laser radiation. A similar effect of involvement (superposition) also takes place for excitons. This fact can be used for calculations of the cross section for neutron inelastic scattering by excitons, which is proportional to the scattering of neutron on nuclei cross section. The paper also discussed the effect of laser radiation of neutron-induced nuclear reaction (radiative capture and threshold reactions)
Photon migration in non-scattering tissue and the effects on image reconstruction
Dehghani, H.; Delpy, D. T.; Arridge, S. R.
1999-12-01
Photon propagation in tissue can be calculated using the relationship described by the transport equation. For scattering tissue this relationship is often simplified and expressed in terms of the diffusion approximation. This approximation, however, is not valid for non-scattering regions, for example cerebrospinal fluid (CSF) below the skull. This study looks at the effects of a thin clear layer in a simple model representing the head and examines its effect on image reconstruction. Specifically, boundary photon intensities (total number of photons exiting at a point on the boundary due to a source input at another point on the boundary) are calculated using the transport equation and compared with data calculated using the diffusion approximation for both non-scattering and scattering regions. The effect of non-scattering regions on the calculated boundary photon intensities is presented together with the advantages and restrictions of the transport code used. Reconstructed images are then presented where the forward problem is solved using the transport equation for a simple two-dimensional system containing a non-scattering ring and the inverse problem is solved using the diffusion approximation to the transport equation.
Photon migration in non-scattering tissue and the effects on image reconstruction
International Nuclear Information System (INIS)
Dehghani, H.; Delpy, D.T.; Arridge, S.R.
1999-01-01
Photon propagation in tissue can be calculated using the relationship described by the transport equation. For scattering tissue this relationship is often simplified and expressed in terms of the diffusion approximation. This approximation, however, is not valid for non-scattering regions, for example cerebrospinal fluid (CSF) below the skull. This study looks at the effects of a thin clear layer in a simple model representing the head and examines its effect on image reconstruction. Specifically, boundary photon intensities (total number of photons exiting at a point on the boundary due to a source input at another point on the boundary) are calculated using the transport equation and compared with data calculated using the diffusion approximation for both non-scattering and scattering regions. The effect of non-scattering regions on the calculated boundary photon intensities is presented together with the advantages and restrictions of the transport code used. Reconstructed images are then presented where the forward problem is solved using the transport equation for a simple two-dimensional system containing a non-scattering ring and the inverse problem is solved using the diffusion approximation to the transport equation. (author)
International Nuclear Information System (INIS)
Babenko, V A; Sychev, Andrei A
2009-01-01
The hyper-Raman scattering (HRS) of light in water is detected reliably by the active spectroscopy method of coherent light scattering, in particular, by the method of four-photon parametric light scattering in a medium in which HRS is a 'signal' wave in the parametric process involving simultaneously two high-power laser photons and IR photons of an 'idler' wave. Hyper-Raman scattering by libration vibrations of water molecules, which virtually cannot be detected by conventional methods of Raman scattering, was observed. (nonlinear optical phenomena)
Scattered and Fluorescent Photon Track Reconstruction in a Biological Tissue
Directory of Open Access Journals (Sweden)
Maria N. Kholodtsova
2014-01-01
Full Text Available Appropriate analysis of biological tissue deep regions is important for tumor targeting. This paper is concentrated on photons’ paths analysis in such biotissue as brain, because optical probing depth of fluorescent and excitation radiation differs. A method for photon track reconstruction was developed. Images were captured focusing on the transparent wall close and parallel to the source fibres, placed in brain tissue phantoms. The images were processed to reconstruct the photons most probable paths between two fibres. Results were compared with Monte Carlo simulations and diffusion approximation of the radiative transfer equation. It was shown that the excitation radiation optical probing depth is twice more than for the fluorescent photons. The way of fluorescent radiation spreading was discussed. Because of fluorescent and excitation radiation spreads in different ways, and the effective anisotropy factor, geff, was proposed for fluorescent radiation. For the brain tissue phantoms it were found to be 0.62±0.05 and 0.66±0.05 for the irradiation wavelengths 532 nm and 632.8 nm, respectively. These calculations give more accurate information about the tumor location in biotissue. Reconstruction of photon paths allows fluorescent and excitation probing depths determination. The geff can be used as simplified parameter for calculations of fluorescence probing depth.
Double electron ionization in Compton scattering of high energy photons by helium atoms
International Nuclear Information System (INIS)
Amusia, M.Y.; Mikhailov, A.I.
1995-01-01
The cross section for double-electron ionization of two-electron atoms and ions in Compton scattering of high energy photons is calculated. It is demonstrated that its dependence on the incoming photon frequency is the same as that for single-electron ionization. The ratio of open-quotes double-to-singleclose quotes ionization in Compton scattering was found to be energy independent and almost identical with the corresponding value for photoionization. For the He atom it is 1.68%. This surprising result deserves experimental verification
Coherent anti-Stokes Raman scattering microscopy with a photonic crystal fiber based light source
DEFF Research Database (Denmark)
Paulsen, H.N.; Hilligsøe, Karen Marie; Thøgersen, J.
2003-01-01
A coherent anti-Stokes Raman scattering microscope based on a Ti:sapphire femtosecond oscillator and a photonic crystal fiber is demonstrated. The nonlinear response of the fiber is used to generate the additional wavelength needed in the Raman process. The applicability of the setup is demonstra......A coherent anti-Stokes Raman scattering microscope based on a Ti:sapphire femtosecond oscillator and a photonic crystal fiber is demonstrated. The nonlinear response of the fiber is used to generate the additional wavelength needed in the Raman process. The applicability of the setup...
Double electron ionization in Compton scattering of high energy photons by helium atoms
Energy Technology Data Exchange (ETDEWEB)
Amusia, M.Y.; Mikhailov, A.I. [St. Petersburg Nuclear Physics Institute, Gatchina (Russian Federation)
1995-08-01
The cross section for double-electron ionization of two-electron atoms and ions in Compton scattering of high energy photons is calculated. It is demonstrated that its dependence on the incoming photon frequency is the same as that for single-electron ionization. The ratio of {open_quotes}double-to-single{close_quotes} ionization in Compton scattering was found to be energy independent and almost identical with the corresponding value for photoionization. For the He atom it is 1.68%. This surprising result deserves experimental verification.
The investigation of the elastic photon scattering cross sections by copper atoms and ions
International Nuclear Information System (INIS)
Kuplyauskene, A.B.
1976-01-01
The differential cross sections of coherent scattering of photons on a copper atom and ions Cu + and Cu 2+ and also on ions Zn + and Ga 2+ in their ground states have been studied theoretically. The energy of an incident photon has varied in the range from 0.5 keV to 200 keV, and the scattering cross sections are given for angles of 30 deg, 60 deg, 90 deg, 120 deg, 150 deg. The calculations are performed in the formfactor approximation with the use of generalized hydrogen-like analytical radial orbitals. To clarify the contribution from individual shells the cross sections of photon scattering on individual electron of shells are calculated. It follows from the calculations that when the energies of the incident photon are less than 4 keV, the main contribution into the differential cross section is made by external electrons. Then, alongside with the increase of the energy, the contribution of the electrons decreases, and the inner shells begin to play a more important role. Therefore the photon cross sections for the energies greater than 50 keV practically coincide for atoms and ions of copper. The general regularities of the cross section variation accompanying the increase of the photon energy are similar for all the elements under study. The angular dependences of cross sections are such that they decrease first and after reaching the minimum at angles of 90 deg - 120 deg increase again
Two-photon exchange corrections in elastic lepton-proton scattering
Energy Technology Data Exchange (ETDEWEB)
Tomalak, Oleksandr; Vanderhaeghen, Marc [Johannes Gutenberg Universitaet Mainz (Germany)
2015-07-01
The measured value of the proton charge radius from the Lamb shift of energy levels in muonic hydrogen is in strong contradiction, by 7-8 standard deviations, with the value obtained from electronic hydrogen spectroscopy and the value extracted from unpolarized electron-proton scattering data. The dominant unaccounted higher order contribution in scattering experiments corresponds to the two photon exchange (TPE) diagram. The elastic contribution to the TPE correction was studied with the fixed momentum transfer dispersion relations and compared to the hadronic model with off-shell photon-nucleon vertices. A dispersion relation formalism with one subtraction was proposed. Theoretical predictions of the TPE elastic contribution to the unpolarized elastic electron-proton scattering and polarization transfer observables in the low momentum transfer region were made. The TPE formalism was generalized to the case of massive leptons and the elastic contribution was evaluated for the kinematics of upcoming muon-proton scattering experiment (MUSE).
Analytical calculations of multiple scattering for high energy photons and neutrons
International Nuclear Information System (INIS)
Thoe, R.S.
1994-04-01
Radiography of large dense objects often require the use of highly penetrating radiation. For example, a couple of centimeters of steel attenuates 50 keV x-rays by a factor of approximately 10 -14 whereas this same amount of steel would attenuate a 500 keV photon beam by only a factor of about 0.25. However, this increase in penetrating power comes with a price. In the case of x-radiation there are two bills to pay: (1) For projection radiography, this increase in penetration directly causes a corresponding decrease in resolution. (2) This increase in penetration occurs in a region where the interaction of radiation and matter is changing from absorption to scattering. In the above example the fraction of scattering goes from about 0.1 at 50 keV to over 0.99 at 500 keV. These scattered photons can significantly degrade contrast. In order to overcome some of these difficulties, radiography using scattered photons has been studied by myself and numerous other authors. In all the above cases, calculation of the intensity of scattered radiation is of primary importance. In cases where scattering is probable, multiple scattering can also be probable. Calculations of multiple scattering are generally very difficult and usually require the use of extremely sophisticated Monte Carlo simulations. It is not unusual for these calculations to require several hours of CPU time on some of the worlds largest and fastest supercomputers. In this paper I will present an alternative approach. I will present an analytical solution to the equations of double scattering, and show how this solution can extended to the case of higher order scattering. Finally, I will give numerical examples of these solutions and compare them to solutions obtained by Monte Carlo simulations
Two-photon interference : spatial aspects of two-photon entanglement, diffraction, and scattering
Peeters, Wouter Herman
2010-01-01
This dissertation contains scientific research within the realm of quantum optics, which is a branch of physics. An experimental and theoretical study is made of two-photon interference phenomena in various optical systems. Spatially entangled photon pairs are produced via the nonlinear optical
Lillich, Joachim
2003-01-01
For the first time at LEP the production of prompt photons is studied in the collisions of quasi-real photons using the OPAL data taken at e+e- centre-of mass energies between 183 GeV and 209 GeV. The total inclusive production cross-section for isolated prompt photons in the kinematic range of transverse momentum > 3.0 GeV and the absolut value of pseudorapidity <1 is determined to be (0.32 +- 0.04 (stat) +- 0.04 (sys)) pb. Differential cross-sections are compared to the predictions of a next-to-leading-order (NLO) calculation. In the second part of this thesis inclusive differential neutral pion cross-sections in photon photon collisons are measured. This measurement is an important test of QCD. In addition this process is the main background for prompt photons.
Photoabsorption and Compton scattering in ionization of helium at high photon energies
International Nuclear Information System (INIS)
Andersson, L.R.; Burgdoerfer, J.; Tennessee Univ., Knoxville, TN
1993-01-01
Production of singly and doubly charged helium ions by impact of keV photons is studied. The ratio R ph = σ ph ++ /σ ph + for photoabsorption is calculated in the photon-energy range 2--18 keV using correlated initial- and final- state wave functions. Extrapolation towards asymptotic photon energies yields R ph (ω → ∞) = 1.66% in agreement with previous predictions. Ionization due to Compton scattering, which becomes comparable to photoabsorption above ω ∼ 3 keV, is discussed
Soft X-ray production by photon scattering in pulsating binary neutron star sources
International Nuclear Information System (INIS)
Bussard, R.W.; Meszaros, P.; Alexander, S.
1985-01-01
A new mechanism is proposed as a source of soft (less than 1 keV) radiation in binary pulsating X-ray sources, in the form of photon scattering which leaves the electron in an excited Landau level. In a plasma with parameters typical of such sources, the low-energy X-ray emissivity of this mechanism far exceeds that of bremsstrahlung. This copious source of soft photons is quite adequate to provide the seed photons needed to explain the power-law hard X-ray spectrum by inverse Comptonization on the hot electrons at the base of the accretion column. 13 references
DEFF Research Database (Denmark)
Nielsen, Per Kær; Gregersen, Niels; Mørk, Jesper
2013-01-01
A solid-state single-photon source emitting indistinguishable photons on-demand is an essential component of linear optics quantum computing schemes. However, the emitter will inevitably interact with the solid-state environment causing decoherence and loss of indistinguishability. In this paper......, we present a comprehensive theoretical treatment of the influence of phonon scattering on the coherence properties of single photons emitted from semiconductor quantum dots. We model decoherence using a full microscopic theory and compare with standard Markovian approximations employing Lindblad...
Photonic Rutherford scattering: A classical and quantum mechanical analogy in ray and wave optics
Selmke, Markus; Cichos, Frank
2013-06-01
Using Fermat's least-optical-path principle, the family of ray trajectories through a special (but common) type of a gradient refractive index lens n(r)=n0+ΔnR /r is solved analytically. The solution gives a ray equation r(ϕ) that is closely related to Rutherford scattering trajectories; we therefore refer to this refraction process as "photonic Rutherford scattering." It is shown that not only do the classical limits correspond but also the wave-mechanical pictures coincide—the time-independent Schrödingier equation and the Helmholtz equation permit the same mapping between the scattering of massive particles and optical scalar waves. Scattering of narrow beams of light finally recovers the classical trajectories. The analysis suggests that photothermal single-particle microscopy measures photonic Rutherford scattering in specific limits and allows for an individual single-scatterer probing. A macroscopic experiment is demonstrated to directly measure the scattering angle to impact parameter relation, which is otherwise accessible only indirectly in Rutherford-scattering experiments.
Energy Technology Data Exchange (ETDEWEB)
Osuch, S.; Popkiewicz, M.; Szeflinski, Z.; Wilhelmi, Z. [Warsaw Univ., Inst. of Experimental Physics, Warsaw (Poland)
1995-12-31
The Bell`s inequality has been experimentally tested using angular correlation of Compton-scattered photons from annihilation of positrons emitted from {sup 22}Na source. The result shows a better agreement with the quantum mechanics predictions rather than with the Bell`s inequality. 7 refs, 5 figs, 1 tab.
DEFF Research Database (Denmark)
Pedersen, Pernille Klarskov; Isomäki, Antti; Hansen, Kim P.
2011-01-01
Photonic crystal fiber (PCF) designs with two zero-dispersion wavelengths (ZDWs) are experimentally investigated in order to suggest a novel PCF for coherent anti-Stokes Raman scattering (CARS) microscopy. From our investigation, we select the optimum PCF design and demonstrate a tailored spectru...
International Nuclear Information System (INIS)
Osuch, S.; Popkiewicz, M.; Szeflinski, Z.; Wilhelmi, Z.
1995-01-01
The Bell's inequality has been experimentally tested using angular correlation of Compton-scattered photons from annihilation of positrons emitted from 22 Na source. The result shows a better agreement with the quantum mechanics predictions rather than with the Bell's inequality
DEFF Research Database (Denmark)
Andresen, Esben Ravn; Paulsen, Henrik Nørgaard; Birkedal, Victoria
2006-01-01
We demonstrate spectral multiplex coherent anti-Stokes Raman scattering (CARS) spectroscopy and microscopy based on a single Ti:sapphire oscillator and a nonlinear photonic-crystal fiber (PCF). The Stokes pulse is generated by spectral conversion of the laser pulse in a PCF. The pump pulse is eit...
Czech Academy of Sciences Publication Activity Database
Pinkhasova, P.; Chen, H.; Kaňka, Jiří; Mergo, P.; Du, H.
2015-01-01
Roč. 106, č. 7 (2015), 0711061-0711064 ISSN 0003-6951 R&D Projects: GA MŠk(CZ) LH11038 Institutional support: RVO:67985882 Keywords : Photonic crystal fibers * Raman scattering * Crystal whiskers Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 3.142, year: 2015
Evidence of Light-by-Light Scattering with Real Photons
Energy Technology Data Exchange (ETDEWEB)
Boege, J.
2003-12-19
In a new experiment at the Stanford Linear Accelerator Center, heretofore untested aspects of high field strength Quantum Electrodynamics were probed. Bunches of 46.6 GeV electrons available in the Final Focus Test Beam line were brought into collision with terawatt pulses of either 1.17 eV or 2.34 eV photons from a Nd:Glass laser system. Several physical process were investigated. This thesis describes the production of electron-positron pairs in photon-photon collisions. This is particularly interesting since it represents the generation of massive particles from massless particles. The bunch/pulse trajectories are approximately antiparallel. Due to the head-on nature of the collisions, the electrons see, in their rest frame, a transformed laser pulse electric field amplitude {bar {var_epsilon}}{sub 0} = 2{gamma}{var_epsilon}{sub 0}, and so a lab frame field {var_epsilon} {approx} 1.0 x 10{sup 11} V/cm corresponds to a 46.6 GeV electron rest frame field {bar {var_epsilon}}{sub 0} {approx} 1.8 x 10{sup 16} V/cm. For electric field amplitudes of this magnitude, perturbative QED is of limited validity. Multiphoton processes dominate collision results. The geometry of the experiments was such that any pairs produced came into existence in the midst of the electron/photon collision region. The electron from a produced pair was indistinguishable from the recoil electrons generated via other processes in collisions. Detecting the positron, then, was the only way to observe pair production. In data accumulated during the September 1994 Final Focus Test Beam run, positrons in excess of background were detected. Positron signals were extracted from an ensemble of data collected during electron bunch/laser pulse collisions. Calorimeter readings were used to measure the energy, and reconstruct the transverse displacement of positrons propagating downstream from the bunch/pulse collision region. Field maps of permanent magnets located downstream of the collision region but
Redundant information from thermal illumination: quantum Darwinism in scattered photons
Energy Technology Data Exchange (ETDEWEB)
Jess Riedel, C; Zurek, Wojciech H, E-mail: criedel@physics.ucsb.edu [Theory Division, LANL, Los Alamos, NM 87545 (United States)
2011-07-15
We study quantum Darwinism, the redundant recording of information about the preferred states of a decohering system by its environment, for an object illuminated by a blackbody. We calculate the quantum mutual information between the object and its photon environment for blackbodies that cover an arbitrary section of the sky. In particular, we demonstrate that more extended sources have a reduced ability to create redundant information about the system, in agreement with previous evidence that initial mixedness of an environment slows-but does not stop-the production of records. We also show that the qualitative results are robust for more general initial states of the system.
Redundant information from thermal illumination: quantum Darwinism in scattered photons
Jess Riedel, C.; Zurek, Wojciech H.
2011-07-01
We study quantum Darwinism, the redundant recording of information about the preferred states of a decohering system by its environment, for an object illuminated by a blackbody. We calculate the quantum mutual information between the object and its photon environment for blackbodies that cover an arbitrary section of the sky. In particular, we demonstrate that more extended sources have a reduced ability to create redundant information about the system, in agreement with previous evidence that initial mixedness of an environment slows—but does not stop—the production of records. We also show that the qualitative results are robust for more general initial states of the system.
Non-Markovian dynamics of a qubit due to single-photon scattering in a waveguide
Fang, Yao-Lung L.; Ciccarello, Francesco; Baranger, Harold U.
2018-04-01
We investigate the open dynamics of a qubit due to scattering of a single photon in an infinite or semi-infinite waveguide. Through an exact solution of the time-dependent multi-photon scattering problem, we find the qubit's dynamical map. Tools of open quantum systems theory allow us then to show the general features of this map, find the corresponding non-Linbladian master equation, and assess in a rigorous way its non-Markovian nature. The qubit dynamics has distinctive features that, in particular, do not occur in emission processes. Two fundamental sources of non-Markovianity are present: the finite width of the photon wavepacket and the time delay for propagation between the qubit and the end of the semi-infinite waveguide.
Calculation of HPGe Detector Response for NRF Photons Scattered from Threat Materials
International Nuclear Information System (INIS)
Park, B. G.; Choi, H. D.
2009-01-01
Nuclear Resonance Fluorescence (NRF) is a process of resonant nuclear absorption of photons, followed by deexcitation with emission of fluorescence photons. The cross section of NRF photons process is given by σ i max ≡ 2π(λ/2π) 2 2J+1/2J 0 +1 Γ 0 Γ i /Γ tot 2 , where λ is the wavelength of the photon, J 0 and J are the nuclear spins of the ground state and excited state, respectively, Γ 0 , Γ i and Γ tot are decay width for deexcitation to the ground state, to the i-th mode state and total decay width, respectively. NRF based security inspection technique uses the signatures of resonance energies of the fluorescence photon scattered from nuclides of the illicit materials in cargo container. NRF can be used to identify the material type, quantity and location. It is performed by measuring the fluorescence photon and the transmitted photon spectrum while irradiating Bremsstrahlung photon beam to the sample
Glucose detection in a highly scattering medium with diffuse photon-pair density wave
Directory of Open Access Journals (Sweden)
Li-Ping Yu
2017-01-01
Full Text Available We propose a novel optical method for glucose measurement based on diffuse photon-pair density wave (DPPDW in a multiple scattering medium (MSM where the light scattering of photon-pair is induced by refractive index mismatch between scatters and phantom solution. Experimentally, the DPPDW propagates in MSM via a two-frequency laser (TFL beam wherein highly correlated pairs of linear polarized photons are generated. The reduced scattering coefficient μ2s′ and absorption coefficient μ2a of DPPDW are measured simultaneously in terms of the amplitude and phase measurements of the detected heterodyne signal under arrangement at different distances between the source and detection fibers in MSM. The results show that the sensitivity of glucose detection via glucose-induced change of reduced scattering coefficient (δμ2s′ is 0.049%mM−1 in a 1% intralipid solution. In addition, the linear range of δμ2s′ vs glucose concentration implies that this DPPDW method can be used to monitor glucose concentration continuously and noninvasively subcutaneously.
Direct imaging of turbid media using long-time back-scattered photons, a numerical study
International Nuclear Information System (INIS)
Boulanger, Joan; Liu, Fengshan; El Akel, Azad; Charette, Andre
2006-01-01
Direct imaging is a convenient way to obtain information on the interior of a semi-transparent turbid material by non-invasive probing using laser beams. The major difficulty is linked to scattering which scrambles the directional information coming from the laser beam. It is found in this paper that the long-term multiple-scattered reflected photons may provide structural information on the inside of a material, which offers an interesting alternative to using information only from un-scattered or least-scattered photons as obtained from current direct imaging set-ups for thin media. Based on some observations on a non-homogeneous three layered 1-D slab irradiated by a laser pulse, a direct probing methodology making use of the long-term back-scattered photons is illustrated to recover inclusions positions in a turbid 2-D medium. First, the numerical model is presented. Second, an extended parametrical study is conducted on 1-D homogeneous and non-homogeneous slabs with different laser pulse durations. It is found that the reflected asymptotic logarithmic slope carries information about the presence of the inclusion and that short laser pulses are not necessary since only the decaying parts of the remanent optical signature is important. Longer laser pulses allow a higher level of energy injection and signal to noise ratio. Third, those observations are used for the probing of a 2-D non-homogeneous phantom. (author)
Coherent photon scattering cross sections for helium near the delta resonance
International Nuclear Information System (INIS)
Delli Carpini, D.; Booth, E.C.; Miller, J.P.; Igarashi, R.; Bergstrom, J.; Caplan, H.; Doss, M.; Hallin, E.; Rangacharyulu, C.; Skopik, D.; Lucas, M.A.; Nathan, A.M.; Wells, D.P.
1991-01-01
The angular distributions for coherent photon scattering from 4 He were measured at average laboratory bremsstrahlung energies of 187, 235, and 280 MeV. The experiment was performed at the Saskatchewan Accelerator Laboratory using the new high duty factor electron beam. The scattered photons were observed with a high-resolution NaI(Tl) total absorption scintillation detector. These measurements are intended to investigate modification of the Δ properties inside the nuclear medium and the treatment of nonresonant contributions to the scattering cross sections. The results are compared to theoretical calculations in the isobar-hole model. Clear deviations from the theory are evident at all energies, especially at 187 MeV
High energy deeply virtual Compton scattering on a photon and related meson exclusive production
International Nuclear Information System (INIS)
Machado, Magno V. T.
2007-01-01
In this work we estimate the differential cross section for the high energy deeply virtual Compton scattering on a photon target, γ*γ→γγ, within the QCD dipole-dipole scattering formalism. For the phenomenology, a saturation model for the dipole-dipole cross section for two photon scattering is considered. Its robustness is supported by a good description of current accelerator data. In addition, we consider the related exclusive vector meson production processes, γ*γ→Vγ. This analysis is focused on the light ρ and φ meson production, which produces larger cross sections. The phenomenological results are compared with the theoretical calculation using the color-dipole Balitsky-Fadin-Kuraev-Lipatov approach
A hybrid approach to simulate multiple photon scattering in X-ray imaging
International Nuclear Information System (INIS)
Freud, N.; Letang, J.-M.; Babot, D.
2005-01-01
A hybrid simulation approach is proposed to compute the contribution of scattered radiation in X- or γ-ray imaging. This approach takes advantage of the complementarity between the deterministic and probabilistic simulation methods. The proposed hybrid method consists of two stages. Firstly, a set of scattering events occurring in the inspected object is determined by means of classical Monte Carlo simulation. Secondly, this set of scattering events is used as a starting point to compute the energy imparted to the detector, with a deterministic algorithm based on a 'forced detection' scheme. For each scattering event, the probability for the scattered photon to reach each pixel of the detector is calculated using well-known physical models (form factor and incoherent scattering function approximations, in the case of Rayleigh and Compton scattering respectively). The results of the proposed hybrid approach are compared to those obtained with the Monte Carlo method alone (Geant4 code) and found to be in excellent agreement. The convergence of the results when the number of scattering events increases is studied. The proposed hybrid approach makes it possible to simulate the contribution of each type (Compton or Rayleigh) and order of scattering, separately or together, with a single PC, within reasonable computation times (from minutes to hours, depending on the number of pixels of the detector). This constitutes a substantial benefit, compared to classical simulation methods (Monte Carlo or deterministic approaches), which usually requires a parallel computing architecture to obtain comparable results
A hybrid approach to simulate multiple photon scattering in X-ray imaging
Energy Technology Data Exchange (ETDEWEB)
Freud, N. [CNDRI, Laboratory of Nondestructive Testing using Ionizing Radiations, INSA-Lyon Scientific and Technical University, Bat. Antoine de Saint-Exupery, 20, avenue Albert Einstein, 69621 Villeurbanne Cedex (France)]. E-mail: nicolas.freud@insa-lyon.fr; Letang, J.-M. [CNDRI, Laboratory of Nondestructive Testing using Ionizing Radiations, INSA-Lyon Scientific and Technical University, Bat. Antoine de Saint-Exupery, 20, avenue Albert Einstein, 69621 Villeurbanne Cedex (France); Babot, D. [CNDRI, Laboratory of Nondestructive Testing using Ionizing Radiations, INSA-Lyon Scientific and Technical University, Bat. Antoine de Saint-Exupery, 20, avenue Albert Einstein, 69621 Villeurbanne Cedex (France)
2005-01-01
A hybrid simulation approach is proposed to compute the contribution of scattered radiation in X- or {gamma}-ray imaging. This approach takes advantage of the complementarity between the deterministic and probabilistic simulation methods. The proposed hybrid method consists of two stages. Firstly, a set of scattering events occurring in the inspected object is determined by means of classical Monte Carlo simulation. Secondly, this set of scattering events is used as a starting point to compute the energy imparted to the detector, with a deterministic algorithm based on a 'forced detection' scheme. For each scattering event, the probability for the scattered photon to reach each pixel of the detector is calculated using well-known physical models (form factor and incoherent scattering function approximations, in the case of Rayleigh and Compton scattering respectively). The results of the proposed hybrid approach are compared to those obtained with the Monte Carlo method alone (Geant4 code) and found to be in excellent agreement. The convergence of the results when the number of scattering events increases is studied. The proposed hybrid approach makes it possible to simulate the contribution of each type (Compton or Rayleigh) and order of scattering, separately or together, with a single PC, within reasonable computation times (from minutes to hours, depending on the number of pixels of the detector). This constitutes a substantial benefit, compared to classical simulation methods (Monte Carlo or deterministic approaches), which usually requires a parallel computing architecture to obtain comparable results.
Shintake, Tsumoru
2008-10-01
The number of photons produced by coherent x-ray scattering from a single biomolecule is very small because of its extremely small elastic-scattering cross section and low damage threshold. Even with a high x-ray flux of 3 x 10;{12} photons per 100-nm -diameter spot and an ultrashort pulse of 10 fs driven by a future x-ray free electron laser (x-ray FEL), it has been predicted that only a few 100 photons will be produced from the scattering of a single lysozyme molecule. In observations of scattered x rays on a detector, the transfer of energy from wave to matter is accompanied by the quantization of the photon energy. Unfortunately, x rays have a high photon energy of 12 keV at wavelengths of 1A , which is required for atomic resolution imaging. Therefore, the number of photoionization events is small, which limits the resolution of imaging of a single biomolecule. In this paper, I propose a method: instead of directly observing the photons scattered from the sample, we amplify the scattered waves by superimposing an intense coherent reference pump wave on it and record the resulting interference pattern on a planar x-ray detector. Using a nanosized gold particle as a reference pump wave source, we can collect 10;{4}-10;{5} photons in single shot imaging where the signal from a single biomolecule is amplified and recorded as two-dimensional diffraction intensity data. An iterative phase retrieval technique can be used to recover the phase information and reconstruct the image of the single biomolecule and the gold particle at the same time. In order to precisely reconstruct a faint image of the single biomolecule in Angstrom resolution, whose intensity is much lower than that of the bright gold particle, I propose a technique that combines iterative phase retrieval on the reference pump wave and the digital Fourier transform holography on the sample. By using a large number of holography data, the three-dimensional electron density map can be assembled.
Enhancement of Raman scattering from monolayer graphene by photonic crystal nanocavities
Kimura, Issei; Yoshida, Masahiro; Sota, Masaki; Inoue, Taiki; Chiashi, Shohei; Maruyama, Shigeo; Kato, Yuichiro K.
Monolayer graphene is an atomically thin two-dimensional material that shows strong Raman scattering, while photonic crystal nanocavities with small mode volumes allow for efficient optical coupling at the nanoscale. Here we demonstrate resonant enhancement of graphene Raman G' band by coupling to photonic crystal cavity modes. Hexagonal-lattice photonic crystal L3 cavities are fabricated from silicon-on-insulator substrates. and monolayer graphene sheets grown by chemical vapor deposition are transferred onto the nanocavities. Excitation wavelength dependence of Raman spectra show that the Raman intensity is enhanced when the G' peak is in resonance with the cavity mode. By performing imaging measurements, we confirm that such an enhancement is only observed at the cavity position. Work supported by JSPS KAKENHI Grant Numbers JP16K13613, JP25107002 and MEXT (Photon Frontier Network Program, Nanotechnology Platform).
Measurement of isolated photon production in deep-inelastic scattering at HERA
International Nuclear Information System (INIS)
Aaron, F.D.; Alexa, C.
2007-10-01
The production of isolated photons in deep-inelastic scattering ep → eγX is measured with the H1 detector at HERA. The measurement is performed in the kinematic range of negative four-momentum transfer squared 4 2 2 and a mass of the hadronic system W X >50 GeV. The analysis is based on a total integrated luminosity of 227 pb -1 . The production cross section of isolated photons with a transverse energy in the range 3 γ T γ γ T , η γ and Q 2 . Isolated photon cross sections are also measured for events with no jets or at least one hadronic jet. The measurements are compared with predictions from Monte Carlo generators modelling the photon radiation from the quark and the electron lines, as well as with calculations at leading and next to leading order in the strong coupling. The predictions significantly underestimate the measured cross sections. (orig.)
International Nuclear Information System (INIS)
Singh, Gurvinderjit; Singh, Manpreet; Sandhu, B.S.; Singh, Bhajan
2008-01-01
The energy, intensity and angular distributions of multiple scattering of 662 keV gamma photons, emerging from targets of pure elements and binary alloys, are observed as a function of target thickness in reflection and transmission geometries. The observed spectra recorded by a properly shielded NaI (Tl) scintillation detector, in addition to singly scattered events, consist of photons scattered more than once for thick targets. To extract the contribution of multiply scattered photons from the measured spectra, a singly scattered distribution is reconstructed analytically. We observe that the numbers of multiply scattered events increase with increase in target thickness, and saturate for a particular thickness called saturation thickness. The saturation thickness decreases with increasing atomic number. The multiple scattering, an interfering background noise in Compton profiles and Compton cross-section measurements, has been successfully used as a new technique to assign the 'effective atomic number' to binary alloys. Monte Carlo calculations support the present experimental results
Analysis of the factors that affect photon counts in Compton scattering
International Nuclear Information System (INIS)
Luo, Guang; Xiao, Guangyu
2015-01-01
Compton scattering has been applied in a variety of fields. The factors that affect Compton scattering have been studied extensively in the literature. However, the factors that affect the measured photon counts in Compton scattering are rarely considered. In this paper, we make a detailed discussion on those factors. First, Compton scattering experiments of some alloy series and powder mixture series are explored. Second, the electron density is researched in terms of atom and lattice constants. Third, the factor of attenuation coefficient is discussed. And then, the active degree of electrons is discussed based on the DFT theory. Lastly, the conclusions are made, that the factors affecting Compton scattering photon counts include mainly electron number density, attenuation coefficient and active degree of electrons. - Highlights: • Compton scattering experiments of some alloy series and powder mixture series are explored. • The influence of electron density is researched in terms of atom and lattice constants. • The influence of attenuation coefficient is discussed. • The active degree of electrons is discussed detailedly based on DFT theory
Ultraweak photon emission as a non-invasive health assessment: A systematic review
Ives, J.A.; Wijk, E.P.A. van; Bat, N.; Crawford, C.; Walter, A.; Jonas, W.B.; Wijk, R. van; Greef, J. van der
2014-01-01
We conducted a systematic review (SR) of the peer reviewed scientific literature on ultraweak photon emissions (UPE) from humans. The question was: Can ultraweak photon emissions from humans be used as a non-invasive health assessment? A systematic search was conducted across eight relevant
Energy Technology Data Exchange (ETDEWEB)
Acharya, V B; Ghumman, B S [Punjabi Univ., Patiala (India). Dept. of Physics
1980-06-01
Differential cross-sections for incoherent scattering of 145 keV photons from K-shell electrons of tin, silver and molybdenum have been measured at 110deg to investigate the effect of electron binding on differential cross-sections in the low energy region. The incoherent scattered photons are selected in coincidence with X-rays which follow the vacancies caused by the ejection of the electrons. NaI(Tl) scintillators are used for the detection of scattered photons and emitted X-rays. The experimental results are compared with the available theoretical data.
International Nuclear Information System (INIS)
Bradley, D.A.
1988-01-01
A variant of the multisection filter and annular target geometry, with a designed angular acceptance of +-0.5 0 , has been utilised in measuring accurate, O(5%), absolute total differential scattering cross sections of 60 KeV photons for H 2 O, methyl methacrylate (C 5 H 8 O 2 ) n and nylon-6 (C 12 H 22 O 3 N 2 ) n in the angular scattering range of 2 0 -10 0 . The effects of molecular correlations manifest, to varying degree, in strong forward peaking of the scattered photon distribution. Comparison is made with available experiment and theory [pt
Strong-field QED processes in short laser pulses. One- and two-photon Compton scattering
Energy Technology Data Exchange (ETDEWEB)
Seipt, Daniel
2012-12-20
The purpose of this thesis is to advance the understanding of strong-field QED processes in short laser pulses. The processes of non-linear one-photon and two-photon Compton scattering are studied, that is the scattering of photons in the interaction of relativistic electrons with ultra-short high-intensity laser pulses. These investigations are done in view of the present and next generation of ultra-high intensity optical lasers which are supposed to achieve unprecedented intensities of the order of 10{sup 24} W/cm{sup 2} and beyond, with pulse lengths in the order of some femtoseconds. The ultra-high laser intensity requires a non-perturbative description of the interaction of charged particles with the laser field to allow for multi-photon interactions, which is beyond the usual perturbative expansion of QED organized in powers of the fine structure constant. This is achieved in strong-field QED by employing the Furry picture and non-perturbative solutions of the Dirac equation in the presence of a background laser field as initial and final state wave functions, as well as the laser dressed Dirac-Volkov propagator. The primary objective is a realistic description of scattering processes with regard to the finite laser pulse duration beyond the common approximation of infinite plane waves, which is made necessary by the ultra-short pulse length of modern high-intensity lasers. Non-linear finite size effects are identified, which are a result of the interplay between the ultra-high intensity and the ultra-short pulse length. In particular, the frequency spectra and azimuthal photon emission spectra are studied emphasizing the differences between pulsed and infinite laser fields. The proper description of the finite temporal duration of the laser pulse leads to a regularization of unphysical infinities (due to the infinite plane-wave description) of the laser-dressed Dirac-Volkov propagator and in the second-order strong-field process of two-photon Compton
Measurement of isolated photons accompained by jets in deep inelastic ep scattering
International Nuclear Information System (INIS)
Abramowicz, H.; Abt, I.; Adamczyk, L.
2012-06-01
The production of isolated high-energy photons accompanied by jets has been measured in deep inelastic ep scattering with the ZEUS detector at HERA, using an integrated luminosity of 326 pb -1 . Measurements were made for exchanged photon virtualities, Q 2 , in the range 10 to 350 GeV 2 . The photons were measured in the transverse-energy and pseudorapidity ranges 4 γ T γ jet T jet <1.8. Differential cross sections are presented as functions of these quantities. Perturbative QCD predictions give a reasonable description of the shape of the measured cross sections over most of the kinematic range, but the absolute normalisation is typically in disagreement by 20-30%.
Ultrasmall-angle X-ray scattering analysis of photonic crystal structure
International Nuclear Information System (INIS)
Abramova, V. V.; Sinitskii, A. S.; Grigor'eva, N. A.; Grigor'ev, S. V.; Belov, D. V.; Petukhov, A. V.; Mistonov, A. A.; Vasil'eva, A. V.; Tret'yakov, Yu. D.
2009-01-01
The results of an ultrasmall-angle X-ray scattering study of iron(III) oxide inverse opal thin films are presented. The photonic crystals examined are shown to have fcc structure with amount of stacking faults varying among the samples. The method used in this study makes it possible to easily distinguish between samples with predominantly twinned fcc structure and nearly perfect fcc stacking. The difference observed between samples fabricated under identical conditions is attributed to random layer stacking in the self-assembled colloidal crystals used as templates for fabricating the inverse opals. The present method provides a versatile tool for analyzing photonic crystal structure in studies of inverse opals made of various materials, colloidal crystals, and three-dimensional photonic crystals of other types.
Hollow-Core Photonic Crystal Fibers for Surface-Enhanced Raman Scattering Probes
Directory of Open Access Journals (Sweden)
Xuan Yang
2011-01-01
Full Text Available Photonic crystal fiber (PCF sensors based on surface-enhanced Raman scattering (SERS have become increasingly attractive in chemical and biological detections due to the molecular specificity, high sensitivity, and flexibility. In this paper, we review the development of PCF SERS sensors with emphasis on our recent work on SERS sensors utilizing hollow-core photonic crystal fibers (HCPCFs. Specifically, we discuss and compare various HCPCF SERS sensors, including the liquid-filled HCPCF and liquid-core photonic crystal fibers (LCPCFs. We experimentally demonstrate and theoretically analyze the high sensitivity of the HCPCF SERS sensors. Various molecules including Rhodamine B, Rhodamine 6G, human insulin, and tryptophan have been tested to show the excellent performance of these fiber sensors.
Highly localized distributed Brillouin scattering response in a photonic integrated circuit
Zarifi, Atiyeh; Stiller, Birgit; Merklein, Moritz; Li, Neuton; Vu, Khu; Choi, Duk-Yong; Ma, Pan; Madden, Stephen J.; Eggleton, Benjamin J.
2018-03-01
The interaction of optical and acoustic waves via stimulated Brillouin scattering (SBS) has recently reached on-chip platforms, which has opened new fields of applications ranging from integrated microwave photonics and on-chip narrow-linewidth lasers, to phonon-based optical delay and signal processing schemes. Since SBS is an effect that scales exponentially with interaction length, on-chip implementation on a short length scale is challenging, requiring carefully designed waveguides with optimized opto-acoustic overlap. In this work, we use the principle of Brillouin optical correlation domain analysis to locally measure the SBS spectrum with high spatial resolution of 800 μm and perform a distributed measurement of the Brillouin spectrum along a spiral waveguide in a photonic integrated circuit. This approach gives access to local opto-acoustic properties of the waveguides, including the Brillouin frequency shift and linewidth, essential information for the further development of high quality photonic-phononic waveguides for SBS applications.
Measurement of Diffractive Scattering of Photons with Large Momentum Transfer at HERA
Aaron, F.D.; Andreev, V.; Antunovic, B.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Bacchetta, A.; Backovic, S.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Beckingham, M.; Begzsuren, K.; Behnke, O.; Belousov, A.; Berger, N.; Bizot, J.C.; Boenig, M.-O.; 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.; Cassol-Brunner, F.; 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 Roeck, A.; De Wolf, E.A.; Diaconu, C.; Dodonov, V.; Dossanov, A.; Dubak, A.; Eckerlin, G.; Efremenko, V.; Egli, S.; Eliseev, A.; Elsen, E.; Essenov, S.; Falkiewicz, A.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Finke, L.; Fleischer, M.; Fomenko, A.; Gabathuler, E.; Gayler, J.; Ghazaryan, Samvel; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gouzevitch, M.; Grab, C.; Greenshaw, T.; Grell, B.R.; Grindhammer, G.; Habib, S.; Haidt, D.; Hansson, M.; Helebrant, C.; Henderson, R.C.W.; Henschel, H.; Herrera, G.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hreus, T.; Jacquet, M.; Janssen, M.E.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jung, Andreas Werner; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I.R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knutsson, A.; Kogler, R.; Korbel, V.; 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.; Lucaci-Timoce, A.-I.; Lytkin, L.; Makankine, A.; Malinovski, E.; Marage, P.; Marti, Ll.; Martyn, H.-U.; Maxfield, S.J.; Mehta, A.; Meier, K.; 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.; Nankov, K.; Naroska, B.; Naumann, Th.; Newman, Paul R.; Niebuhr, C.; Nikiforov, A.; 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.; Peng, H.; Perez, E.; Petrukhin, A.; Picuric, I.; Piec, S.; Pitzl, D.; Placakyte, R.; Polifka, R.; Povh, B.; Preda, T.; 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.; Salvaire, F.; Sankey, D.P.C.; Sauter, M.; Sauvan, E.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schoning, A.; Schultz-Coulon, H.-C.; Sefkow, F.; Shaw-West, R.N.; Sheviakov, I.; Shtarkov, L.N.; Shushkevich, S.; Sloan, T.; Smiljanic, Ivan; Smirnov, P.; Soloviev, Y.; Sopicki, P.; South, D.; Spaskov, V.; Specka, Arnd E.; Staykova, Z.; Steder, M.; Stella, B.; 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.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, K.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Vinokurova, S.; Volchinski, V.; Wegener, D.; Wessels, M.; Wissing, Ch.; Wunsch, E.; Yeganov, V.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y.C.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.
2009-01-01
The first measurement of diffractive scattering of quasi-real photons with large momentum transfer gamma p -> gamma Y, where Y is the proton dissociative system, is made using the H1 detector at HERA. The measurement is performed for initial photon virtualities Q^2 < 0.01 GeV^2. Cross sections are measured as a function of W, the incident photon-proton entre of mass energy, and t, the square of the four-momentum transferred at the proton vertex, in the range 175 < W < 247 GeV and 4<|t|<36 GeV^2. The W dependence is well described by a model based on perturbative QCD using a leading logarithmic approximation of the BFKL evolution. The measured |t| dependence is harder than that predicted by the model and those observed in exclusive vector meson production.
Review of high energy diffraction in real and virtual photon proton scattering at HERA
Energy Technology Data Exchange (ETDEWEB)
Wolf, G.
2009-07-15
The electron-proton collider HERA at DESY opened the door for the study of diffraction in real and virtual photon-proton scattering at center-of-mass energies W up to 250 GeV and for large negative mass squared -Q{sup 2} of the virtual photon up to Q{sup 2}=1600 GeV{sup 2}. At W = 220 GeV and Q{sup 2}=4 GeV{sup 2}, diffraction accounts for about 15% of the total virtual photon proton cross section decreasing to {approx}5% at Q{sup 2}=200 GeV{sup 2}. An overview of the results obtained by the experiments H1 and ZEUS on the production of neutral vector mesons and on inclusive diffraction up to the year 2008 is presented. (orig.)
Measurement of diffractive scattering of photons with large momentum transfer at HERA
H1 Collaboration; Aaron, F. D.; Alexa, C.; Andreev, V.; Antunovic, B.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Bacchetta, A.; Backovic, S.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Beckingham, M.; Begzsuren, K.; Behnke, O.; Belousov, A.; Berger, N.; Bizot, J. C.; Boenig, M.-O.; 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.; Cassol-Brunner, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Cholewa, A.; Contreras, J. G.; Coughlan, J. A.; Cozzika, G.; Cvach, J.; Dainton, J. B.; Daum, K.; Deák, M.; de Boer, Y.; Delcourt, B.; Del Degan, M.; Delvax, J.; de Roeck, A.; de Wolf, E. A.; Diaconu, C.; Dodonov, V.; Dossanov, A.; Dubak, A.; Eckerlin, G.; Efremenko, V.; Egli, S.; Eliseev, A.; Elsen, E.; Essenov, S.; Falkiewicz, A.; Faulkner, P. J. W.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Finke, L.; Fleischer, M.; Fomenko, A.; Gabathuler, E.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gouzevitch, M.; Grab, C.; Greenshaw, T.; Grell, B. R.; Grindhammer, G.; Habib, S.; Haidt, D.; Hansson, M.; Helebrant, C.; Henderson, R. C. W.; Henschel, H.; Herrera, G.; Hildebrandt, M.; Hiller, K. H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hreus, T.; Jacquet, M.; Janssen, M. E.; Janssen, X.; Jemanov, V.; Jönsson, L.; Johnson, D. P.; Jung, A. W.; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I. R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knutsson, A.; Kogler, R.; Korbel, V.; Kostka, P.; Kraemer, M.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Krüger, K.; Kutak, K.; Landon, M. P. J.; Lange, W.; Laštovička-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.; Lucaci-Timoce, A.-I.; Lytkin, L.; Makankine, A.; Malinovski, E.; Marage, P.; Marti, Ll.; Martyn, H.-U.; Maxfield, S. J.; Mehta, A.; Meier, K.; Meyer, A. B.; Meyer, H.; Meyer, H.; Meyer, J.; Michels, V.; Mikocki, S.; Milcewicz-Mika, I.; Moreau, F.; Morozov, A.; Morris, J. V.; Mozer, M. U.; Mudrinic, M.; Müller, K.; Murín, P.; Nankov, K.; Naroska, B.; Naumann, Th.; Newman, P. R.; Niebuhr, C.; Nikiforov, A.; 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.; Peng, H.; Perez, E.; Petrukhin, A.; Picuric, I.; Piec, S.; Pitzl, D.; Plačakytė, R.; Polifka, R.; Povh, B.; Preda, T.; 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.; Salvaire, F.; Sankey, D. P. C.; Sauter, M.; Sauvan, E.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schöning, A.; Schultz-Coulon, H.-C.; Sefkow, F.; Shaw-West, R. N.; Sheviakov, I.; Shtarkov, L. N.; Shushkevich, S.; Sloan, T.; Smiljanic, I.; Smirnov, P.; Soloviev, Y.; Sopicki, P.; South, D.; Spaskov, V.; Specka, A.; Staykova, Z.; Steder, M.; Stella, B.; 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.; Truöl, P.; Tsakov, I.; Tseepeldorj, B.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, K.; Valkárová, A.; Vallée, C.; van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Vinokurova, S.; Volchinski, V.; Wegener, D.; Wessels, M.; Wissing, Ch.; Wünsch, E.; Yeganov, V.; Žáček, J.; Zálešák, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y. C.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.
2009-02-01
The first measurement of diffractive scattering of quasi-real photons with large momentum transfer γp→γY, where Y is the proton dissociative system, is made using the H1 detector at HERA. The measurement is performed for initial photon virtualities Q<0.01 GeV. Single differential cross sections are measured as a function of W, the incident photon-proton centre of mass energy, and t, the square of the four-momentum transferred at the proton vertex, in the range 175
Measurement of photon production in the very forward direction in deep-inelastic 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; Alexa, C. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Andreev, V. [Lebedev Physical Institute, Moscow (RU)] (and others)
2011-06-15
The production of photons at very small angles with respect to the proton beam direction is studied in deep-inelastic positron-proton scattering at HERA. The data are taken with the H1 detector in the years 2006 and 2007 and correspond to an integrated luminosity of 126 pb{sup -1}. The analysis covers the range of negative four momentum transfer squared at the positron vertex 6photon with pseudorapidity {eta}>7.9 as a function of its transverse momentum p{sub T}{sup lead} and longitudinal momentum fraction of the incoming proton x{sub L}{sup lead}. In addition, the cross sections are studied as a function of the sum of the longitudinal momentum fraction x{sub L}{sup sum} of all photons in the pseudorapidity range {eta}>7.9. The cross sections are normalised to the inclusive deep-inelastic scattering cross section and compared to the predictions of models of deep-inelastic scattering and models of the hadronic interactions of high energy cosmic rays. (orig.)
Measurement of photon production in the very forward direction in deep-inelastic scattering at HERA
Energy Technology Data Exchange (ETDEWEB)
Aaron, F.D.; Alexa, C.; Rotaru, M.; Stoicea, G. [National Inst. for Physics and Nuclear Engineering, Bucharest (Romania); Andreev, V.; Belousov, A.; Eliseev, A.; Fomenko, A.; Gogitidze, N.; Lebedev, A.; Malinovski, E.; Rusakov, S.; Shtarkov, L.N.; Soloviev, Y.; Vazdik, Y. [Lebedev Physical Inst., Moscow (Russian Federation); Backovic, S.; Dubak, A.; Lastovicka-Medin, G.; Picuric, I.; Raicevic, N. [Univ. of Montenegro, Podgorica (ME); Baghdasaryan, A.; Baghdasaryan, S.; Zohrabyan, H. [Yerevan Physics Inst. (Armenia); Barrelet, E. [Univ. Pierre et Marie Curie Paris 6, LPNHE, Paris (France); Univ. Denis Diderot Paris 7, CNRS/IN2P3, Paris (France); Bartel, W.; Belov, P.; Brandt, G.; Brinkmann, M.; Britzger, D.; Campbell, A.J.; Eckerlin, G.; Elsen, E.; Felst, R.; Fischer, D.J.; Fleischer, M.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Gouzevitch, M.; Grebenyuk, A.; Grell, B.R.; Habib, S.; Haidt, D.; Helebrant, C.; Kleinwort, C.; Kogler, R.; Kraemer, M.; Levonian, S.; Lipka, K.; List, J.; Meyer, A.B.; Meyer, J.; Niebuhr, C.; Nowak, K.; Olsson, J.E.; Pahl, P.; Panagoulias, I.; Papadopoulou, T.; Petrukhin, A.; Piec, S.; Pitzl, D.; Schmitt, S.; Sefkow, F.; South, D.; Steder, M.; Wuensch, E. [DESY, Hamburg (Germany); Begzsuren, K.; Ravdandorj, T.; Tseepeldorj, B. [Inst. of Physics and Technology of the Mongolian Academy of Sciences, Ulaanbaatar (Mongolia); Bizot, J.C.; Brisson, V.; Delcourt, B.; Jacquet, M.; Pascaud, C.; Tran, T.H.; Zhang, Z.; Zomer, F. [Univ. Paris-Sud, CNRS/IN2P3, LAL, Orsay (France); Boudry, V.; Moreau, F.; Specka, A. [Ecole Polytechnique, CNRS/IN2P3, LLR, Palaiseau (France); Bozovic-Jelisavcic, I.; Mudrinic, M.; Pandurovic, M.; Smiljanic, I. [Univ. of Belgrade, Vinca Institute of Nuclear Sciences, Belgrade (RS); Bracinik, J.; Kenyon, I.R.; Newman, P.R.; Thompson, P.D. [Univ. of Birmingham (United Kingdom); Bruncko, D.; Cerny, V.; Ferencei, J. [Slovak Academy of Sciences, Inst. of Experimental Physics, Kosice (Slovakia)] [and others
2011-10-15
The production of photons at very small angles with respect to the proton beam direction is studied in deep-inelastic positron-proton scattering at HERA. The data are taken with the H1 detector in the years 2006 and 2007 and correspond to an integrated luminosity of 126 pb{sup -1}. The analysis covers the range of negative four momentum transfer squared at the positron vertex 6photon with pseudorapidity {eta}>7.9 as a function of its transverse momentum p{sub T}{sup lead} and longitudinal momentum fraction of the incoming proton x{sub L}{sup lead}. In addition, the cross sections are studied as a function of the sum of the longitudinal momentum fraction x{sub L}{sup sum} of all photons in the pseudorapidity range {eta}>7.9. The cross sections are normalised to the inclusive deep-inelastic scattering cross section and compared to the predictions of models of deep-inelastic scattering and models of the hadronic interactions of high energy cosmic rays. (orig.)
The HERMES recoil photon detector and the study of deeply virtual Compton scattering
Energy Technology Data Exchange (ETDEWEB)
Hulse, Charlotte van
2011-03-15
The study of deeply virtual Compton scattering (DVCS) gives information about the contribution of the quark orbital angular momentum to the spin of the proton. DVCS has been studied at the HERMES experiment at DESY in Hamburg. Here 27.6 GeV longitudinally polarized electrons and positrons were scattered off a gaseous proton target. For the analysis of DVCS the recoiling proton could not be detected, but was reconstructed via its missing mass. This method suffers, however, from a 14% background contribution, mainly originating from associated DVCS. In this process the proton does not stay in its ground state but is excited to a {delta}{sup +} resonance. In order to reduce the background contribution down to less than 1%, a recoil detector was installed in the HERMES experiment beginning of 2006. This detector consists of three subcomponents, of which one is the photon detector. The main function of the photon detector is the detection of {delta}{sup +} decay photons. The photon detector was started up and commissioned for the analysis of (associated) DVCS. Subsequently DVCS and associated DVCS were analyzed using the recoil detector. (orig.)
Elastic and Raman scattering of photons from the giant dipole resonance
International Nuclear Information System (INIS)
Bar-Noy, T.
1978-12-01
In the present work we investigated nuclear Raman and elastic scattering of photons from the Giant Dipole Resonance (GDR) of medium and heavy nuclei. The photons beams were obtained from thermal neutron capture on V, Fe, Ni, Cu and Cr discs, utilizing the IRR-2 reactor. Nine targets, 159 Tb, 165 Ho, 175 Lu, 181 Ta, 197 Au, 209 Bi, 232 Th, 237 Np, and 238 U, representing all spherical and deformed nuclei in the region of medium and heavy nuclei, were used. As preliminary works, we discovered and investigated the 11.4 MeV γ-line, measured the attenuation coefficients at 9 and 11.4 MeV, performed a numerical calculation of Delbrueck amplitudes and modified the Simple Rotator Model (SRM). The absolute scattering cross-sections were measured for each scatterer at 4-8 different energies, and angular distributions in the range 90 deg to 140 deg were carried out at 9 MeV and 11.4 MeV. The experimental results were compared with theoretical predictions of the modified SRM and the Dynamic Collective Model (DCM). The results proved that the modified SRM describes appropriately the scattering from the GDR, including elastic and Raman absolute cross-sections and their angular distributions. (author)
Amusia, Miron Ya; Yarzhemsky, Victor
2012-01-01
The aim of this book is to present highly accurate and extensive theoretical Atomic data and to give a survey of selected calculational methods for atomic physics, used to obtain these data. The book presents the results of calculations of cross sections and probabilities of a broad variety of atomic processes with participation of photons and electrons, namely on photoabsorption, electron scattering and accompanying effects. Included are data for photoabsorption and electron scattering cross-sections and probabilities of vacancy decay formed for a large number of atoms and ions. Attention is also given to photoionization and vacancy decay in endohedrals and to positron-atom scattering. The book is richly illustrated. The methods used are one-electron Hartree-Fock and the technique of Feynman diagrams that permits to include many-electron correlations. This is done in the frames of the Random Phase approximation with exchange and the many-body perturbation theory. Newly obtained and previously collected atomi...
Inclusive prompt photon production in electron-nucleus scattering at small x
Roy, Kaushik; Venugopalan, Raju
2018-05-01
We compute the differential cross-section for inclusive prompt photon production in deeply inelastic scattering (DIS) of electrons on nuclei at small x in the framework of the Color Glass Condensate (CGC) effective theory. The leading order (LO) computation in this framework resums leading logarithms in x as well as power corrections to all orders in Q s, A 2 / Q 2, where Q s, A ( x) is the nuclear saturation scale. This LO result is proportional to universal dipole and quadrupole Wilson line correlators in the nucleus. In the soft photon limit, the Low-Burnett-Kroll theorem allows us to recover existing results on inclusive DIS dijet production. The k ⊥ and collinearly factorized expressions for prompt photon production in DIS are also recovered in a leading twist approximation to our result. In the latter case, our result corresponds to the dominant next-to-leading order (NLO) perturbative QCD contribution at small x. We next discuss the computation of the NLO corrections to inclusive prompt photon production in the CGC framework. In particular, we emphasize the advantages for higher order computations in inclusive photon production, and for fully inclusive DIS, arising from the simple momentum space structure of the dressed quark and gluon "shock wave" propagators in the "wrong" light cone gauge A - = 0 for a nucleus moving with P N + → ∞.
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
Energy Technology Data Exchange (ETDEWEB)
Henderson, B.S. [Massachusetts Institute of Technology, Cambridge, MA (United States); Ice, L.D. [Arizona State Univ., Tempe, AZ (United States); Khaneft, D. [Mainz Univ. (Germany); Collaboration: OLYMPUS Collaboration; and others
2016-12-15
The OLYMPUS collaboration reports on a precision measurement of the positron-proton to electron-proton elastic cross section ratio, R{sub 2γ}, a direct measure of the contribution of hard two- photon exchange to the elastic cross section. In the OLYMPUS measurement, 2.01 GeV electron and positron beams were directed through a hydrogen gas target internal to the DORIS storage ring at DESY. A toroidal magnetic spectrometer instrumented with drift chambers and time-of-flight scintillators detected elastically scattered leptons in coincidence with recoiling protons over a scattering angle range of ∼20 to 80 . The relative luminosity between the two beam species was monitored using tracking telescopes of interleaved GEM and MWPC detectors at 12 , as well as symmetric Moeller/Bhabha calorimeters at 1.29 . A total integrated luminosity of 4.5 fb{sup -1} was collected. In the extraction of R{sub 2γ}, radiative effects were taken into account using a Monte Carlo generator to simulate the convolutions of internal bremsstrahlung with experiment-specific conditions such as detector acceptance and reconstruction efficiency. The resulting values of R{sub 2γ}, presented here for a wide range of virtual photon polarization 0.456<ε<0.978, are smaller than some hadronic two-photon exchange calculations predict, but are in reasonable agreement with a subtracted dispersion model and a phenomenological fit to the form factor data.
Henderson, B. S.; Ice, L. D.; Khaneft, D.; O'Connor, C.; Russell, R.; Schmidt, A.; Bernauer, J. C.; Kohl, M.; Akopov, N.; Alarcon, R.; Ates, O.; Avetisyan, A.; Beck, R.; Belostotski, S.; Bessuille, J.; Brinker, F.; Calarco, J. R.; Carassiti, V.; Cisbani, E.; Ciullo, G.; Contalbrigo, M.; de Leo, R.; Diefenbach, J.; Donnelly, T. W.; Dow, K.; Elbakian, G.; Eversheim, P. D.; Frullani, S.; Funke, Ch.; Gavrilov, G.; Gläser, B.; Görrissen, N.; Hasell, D. K.; Hauschildt, J.; Hoffmeister, Ph.; Holler, Y.; Ihloff, E.; Izotov, A.; Kaiser, R.; Karyan, G.; Kelsey, J.; Kiselev, A.; Klassen, P.; Krivshich, A.; Lehmann, I.; Lenisa, P.; Lenz, D.; Lumsden, S.; Ma, Y.; Maas, F.; Marukyan, H.; Miklukho, O.; Milner, R. G.; Movsisyan, A.; Murray, M.; Naryshkin, Y.; Perez Benito, R.; Perrino, R.; Redwine, R. P.; Rodríguez Piñeiro, D.; Rosner, G.; Schneekloth, U.; Seitz, B.; Statera, M.; Thiel, A.; Vardanyan, H.; Veretennikov, D.; Vidal, C.; Winnebeck, A.; Yeganov, V.; Olympus Collaboration
2017-03-01
The OLYMPUS Collaboration reports on a precision measurement of the positron-proton to electron-proton elastic cross section ratio, R2 γ , a direct measure of the contribution of hard two-photon exchange to the elastic cross section. In the OLYMPUS measurement, 2.01 GeV electron and positron beams were directed through a hydrogen gas target internal to the DORIS storage ring at DESY. A toroidal magnetic spectrometer instrumented with drift chambers and time-of-flight scintillators detected elastically scattered leptons in coincidence with recoiling protons over a scattering angle range of ≈20 ° to 80°. The relative luminosity between the two beam species was monitored using tracking telescopes of interleaved gas electron multiplier and multiwire proportional chamber detectors at 12°, as well as symmetric Møller or Bhabha calorimeters at 1.29°. A total integrated luminosity of 4.5 fb-1 was collected. In the extraction of R2 γ, radiative effects were taken into account using a Monte Carlo generator to simulate the convolutions of internal bremsstrahlung with experiment-specific conditions such as detector acceptance and reconstruction efficiency. The resulting values of R2 γ, presented here for a wide range of virtual photon polarization 0.456 <ɛ <0.978 , are smaller than some hadronic two-photon exchange calculations predict, but are in reasonable agreement with a subtracted dispersion model and a phenomenological fit to the form factor data.
International Nuclear Information System (INIS)
Singh, Manpreet; Singh, Gurvinderjit; Singh, Bhajan; Sandhu, B.S.
2007-01-01
An inverse response matrix converts the observed pulse-height distribution of a NaI(Tl) scintillation detector to a photon spectrum. This also results in extraction of intensity distribution of multiply scattered events originating from interactions of 0.279 MeV photons with thick targets of soldering material. The observed pulse-height distributions are a composite of singly and multiply scattered events in addition to bremmstrahlung-and Rayleigh-scattered events. To evaluate the contribution of multiply scattered events, the spectrum of singly scattered events contributing to inelastic Compton peak is reconstructed analytically. The optimum thickness (saturation depth), at which the number of multiply scattered events saturates, has been measured. Monte Carlo calculations also support the present results
The effect of scattering on single photon transmission of optical angular momentum
International Nuclear Information System (INIS)
Andrews, D L
2011-01-01
Schemes for the communication and registration of optical angular momentum depend on the fidelity of transmission between optical system components. It is known that electron spin can be faithfully relayed between exciton states in quantum dots; it has also been shown by several theoretical and experimental studies that the use of beams conveying orbital angular momentum can significantly extend the density and efficiency of such information transfer. However, it remains unclear to what extent the operation of such a concept at the single photon level is practicable—especially where this involves optical propagation through a material system, in which forward scattering events can intervene. The possibility of transmitting and decoding angular momentum over nanoscale distances itself raises other important issues associated with near-field interrogation. This paper provides a framework to address these and related issues. A quantum electrodynamical representation is constructed and used to pursue the consequences of individual photons, from a Laguerre–Gaussian beam, undergoing single and multiple scattering events in the course of propagation. In this context, issues concerning orbital angular momentum conservation, and its possible compromise, are tackled by identifying the relevant components of the electromagnetic scattering and coupling tensors, using an irreducible Cartesian basis. The physical interpretation broadly supports the fidelity of quantum information transmission, but it also identifies potential limitations of principle
The effect of scattering on single photon transmission of optical angular momentum
Andrews, D. L.
2011-06-01
Schemes for the communication and registration of optical angular momentum depend on the fidelity of transmission between optical system components. It is known that electron spin can be faithfully relayed between exciton states in quantum dots; it has also been shown by several theoretical and experimental studies that the use of beams conveying orbital angular momentum can significantly extend the density and efficiency of such information transfer. However, it remains unclear to what extent the operation of such a concept at the single photon level is practicable—especially where this involves optical propagation through a material system, in which forward scattering events can intervene. The possibility of transmitting and decoding angular momentum over nanoscale distances itself raises other important issues associated with near-field interrogation. This paper provides a framework to address these and related issues. A quantum electrodynamical representation is constructed and used to pursue the consequences of individual photons, from a Laguerre-Gaussian beam, undergoing single and multiple scattering events in the course of propagation. In this context, issues concerning orbital angular momentum conservation, and its possible compromise, are tackled by identifying the relevant components of the electromagnetic scattering and coupling tensors, using an irreducible Cartesian basis. The physical interpretation broadly supports the fidelity of quantum information transmission, but it also identifies potential limitations of principle.
Measurement of Photon Production in the Very Forward Direction in Deep-Inelastic Scattering at HERA
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.; 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.; 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.; Huber, F.; Jacquet, M.; Janssen, X.; Jonsson, L.; Jung, H.; Kapichine, M.; Kenyon, I.R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Kluge, T.; Kogler, R.; Kostka, P.; Kraemer, M.; Kretzschmar, J.; Kruger, K.; Landon, M.P.J.; Lange, W.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Lendermann, V.; Levonian, S.; Lipka, K.; List, B.; List, J.; Lopez-Fernandez, R.; Lubimov, V.; Lytkin, L.; Makankine, A.; Malinovski, E.; Marage, P.; 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.; Mudrinic, M.; Muller, K.; Naumann, Th.; Newman, P.R.; Niebuhr, C.; Nikitin, D.; Nowak, G.; Nowak, K.; Olsson, J.E.; Ozerov, D.; Pahl, P.; Palichik, V.; Panagoulias, I.; Pandurovic, M.; Papadopoulou, Th.; Pascaud, C.; Patel, G.D.; Perez, E.; Petrukhin, A.; Picuric, I.; Piec, S.; 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.; Tabasco, J.E.Ruiz; 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.; Smiljanic, I.; 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.; Urban, K.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vazdik, Y.; Wegener, D.; Wunsch, E.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zohrabyan, H.; Zomer, F.
2011-01-01
The production of photons at very small angles with respect to the proton beam direction is studied in deep-inelastic positron-proton scattering at HERA. The data are taken with the H1 detector in the years 2006 and 2007 and correspond to an integrated luminosity of $126 \\mathrm{pb}^{-1}$. The analysis covers the range of negative four momentum transfer squared at the positron vertex $67.9$ as a function of its transverse momentum $p_T^{lead}$ and longitudinal momentum fraction of the incoming proton $x_L^{lead}$. In addition, the cross sections are studied as a function of the sum of the longitudinal momentum fraction $x_L^{sum}$ of all photons in the pseudorapidity range $\\eta>7.9$. The cross sections are normalised to the inclusive deep-inelastic scattering cross section and compared to the predictions of models of deep-inelastic scattering and models of the hadronic interactions of high energy cosmic rays.
Measurement of isolated photon production in deep-inelastic scattering at HERA
Aaron, F. D.; Aktas, A.; Alexa, C.; Andreev, V.; Antunovic, B.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Backovic, S.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Beckingham, M.; Begzsuren, K.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, N.; Bizot, J. C.; Boenig, M.-O.; Boudry, V.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Bruncko, D.; Büsser, F. W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A. J.; Cantun Avila, K. B.; Cassol-Brunner, F.; 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 Roeck, A.; de Wolf, E. A.; Diaconu, C.; Dodonov, V.; Dubak, A.; Eckerlin, G.; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Eliseev, A.; Elsen, E.; Essenov, S.; Falkiewicz, A.; Faulkner, P. J. W.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Finke, L.; Fleischer, M.; Fomenko, A.; Franke, G.; Frisson, T.; Gabathuler, E.; Gayler, J.; Ghazaryan, S.; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Gouzevitch, M.; Grab, C.; Greenshaw, T.; Grell, B. R.; Grindhammer, G.; Habib, S.; Haidt, D.; Hansson, M.; Heinzelmann, G.; Helebrant, C.; Henderson, R. C. W.; Henschel, H.; Herrera, G.; Hildebrandt, M.; Hiller, K. H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hreus, T.; Jacquet, M.; Janssen, M. E.; Janssen, X.; Jemanov, V.; Jönsson, L.; Johnson, D. P.; Jung, A. W.; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I. R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knutsson, A.; Korbel, V.; Kostka, P.; Kraemer, M.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Krüger, K.; Landon, M. P. J.; Lange, W.; Laštovička-Medin, G.; Laycock, P.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Li, G.; Lindfeld, L.; Lipka, K.; Liptaj, A.; List, B.; List, J.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lytkin, L.; Makankine, A.; Malinovski, E.; Marage, P.; Marti, L.; Martisikova, M.; Martyn, H.-U.; Maxfield, S. J.; Mehta, A.; Meier, K.; Meyer, A. B.; Meyer, H.; Meyer, H.; Meyer, J.; Michels, V.; Mikocki, S.; Milcewicz-Mika, I.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J. V.; Mozer, M. U.; Müller, K.; Murín, P.; Nankov, K.; Naroska, B.; Naumann, T.; Newman, P. R.; Niebuhr, C.; Nikiforov, A.; Nowak, G.; Nowak, K.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J. E.; Osman, S.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Pandurovic, M.; Papadopoulou, T.; Pascaud, C.; Patel, G. D.; Peng, H.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Picuric, I.; Piec, S.; Pitzl, D.; Plačakytė, R.; Polifka, R.; Povh, B.; Preda, T.; Prideaux, P.; Radescu, V.; Rahmat, A. J.; Raicevic, N.; Ravdandorj, T.; Reimer, P.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Salek, D.; Salvaire, F.; Sankey, D. P. C.; Sauter, M.; Sauvan, E.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schöning, A.; Schultz-Coulon, H.-C.; Sefkow, F.; Shaw-West, R. N.; Sheviakov, I.; Shtarkov, L. N.; Sloan, T.; Smiljanic, I.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, A.; Staykova, Z.; Steder, M.; Stella, B.; Stiewe, J.; 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.; Truöl, P.; Tsakov, I.; Tseepeldorj, B.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, K.; Utkin, D.; Valkárová, A.; Vallée, C.; van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Vinokurova, S.; Volchinski, V.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Wessels, M.; Wissing, C.; Wolf, R.; Wünsch, E.; Xella, S.; Yeganov, V.; Žáček, J.; Zálešák, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y. C.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.
2008-04-01
The production of isolated photons in deep-inelastic scattering ep→eγX is measured with the H1 detector at HERA. The measurement is performed in the kinematic range of negative four-momentum transfer squared 450 GeV. The analysis is based on a total integrated luminosity of 227 pb-1. The production cross section of isolated photons with a transverse energy in the range 3
Energy Technology Data Exchange (ETDEWEB)
Liu, Dan, E-mail: liudanhu725@126.com [School of Physics and Mechanical & Electrical Engineering, Hubei University of Education, Wuhan, 430205 (China); Hu, Sen [School of Physics and Mechanical & Electrical Engineering, Hubei University of Education, Wuhan, 430205 (China); Gao, Yihua [Wuhan National Laboratory for Optoelectronics (WNLO), School of Physics, Huazhong University of Science and Technology (HUST), Wuhan, 430074 (China)
2017-07-12
A 2D orthogonal square-lattice photonic crystal (PC) heterojunction consisting of circular and square air holes in silicon is presented. Band structures are calculated using the plane wave expansion method, and the transmission properties are investigated by the finite-different time-domain simulations. Thanks to the higher diffraction orders excited when the circular and square holes are interlaced along the interface, one-way transmission phenomena can exist within wide frequency regions. The higher order diffraction is further enhanced through two different interface optimization designs proposed by modifying the PC structure of the hetero-interface. An orthogonal PC heterojunction for wide-band and efficient one-way transmission is constructed, and the maximum transmissivity is up to 78%. - Highlights: • Photonic crystal heterojunction with circular and square scatterers is first studied. • One-way transmission efficiency is closely related to the hetero-interface. • Wide-band and efficient one-way transmission is realized.
Polarized photon scattering off 52Cr: Determining the parity of J =1 states
Krishichayan, Bhike, Megha; Tornow, W.; Rusev, G.; Tonchev, A. P.; Tsoneva, N.; Lenske, H.
2015-04-01
The photoresponse of 52Cr has been investigated in the energy range of 5.0-9.5 MeV using the photon scattering technique at the HI γ S facility of TUNL to complement previous work with unpolarized bremsstrahlung photon beams at the Darmstadt linear electron accelerator. The unambiguous parity determinations of the observed J =1 states provides the basis needed to better understand the structure of E 1 and M 1 excitations. Theoretical calculations using the quasiparticle phonon model incorporating self-consistent energy-density functional theory were performed to investigate the fragmentation pattern of the dipole strength below and around the neutron-emission threshold. These results compare very well with the experimental values.
Measurement of diffractive scattering of photons with large momentum transfer at HERA
International Nuclear Information System (INIS)
Aaron, F.D.; Andreev, V.
2008-09-01
The first measurement of diffractive scattering of quasi-real photons with large momentum transfer γp → γY, where Y is the proton dissociative system, is made using the H1 detector at HERA. The measurement is performed for initial photon virtualities Q 2 2 . Cross sections are measured as a function of W, the incident photonproton centre of mass energy, and t, the square of the four-momentum transferred at the proton vertex, in the range 175 2 . The W dependence is well described by a model based on perturbative QCD using a leading logarithmic approximation of the BFKL evolution. The measured vertical stroke t vertical stroke dependence is harder than that predicted by the model and those observed in exclusive vector meson production. (orig.)
Measurement of diffractive scattering of photons with large momentum transfer 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)
2008-09-15
The first measurement of diffractive scattering of quasi-real photons with large momentum transfer {gamma}p {yields} {gamma}Y, where Y is the proton dissociative system, is made using the H1 detector at HERA. The measurement is performed for initial photon virtualities Q{sup 2} < 0.01 GeV{sup 2}. Cross sections are measured as a function of W, the incident photonproton centre of mass energy, and t, the square of the four-momentum transferred at the proton vertex, in the range 175 < W < 247 GeV and 4 < vertical stroke t vertical stroke < 36 GeV{sup 2}. The W dependence is well described by a model based on perturbative QCD using a leading logarithmic approximation of the BFKL evolution. The measured vertical stroke t vertical stroke dependence is harder than that predicted by the model and those observed in exclusive vector meson production. (orig.)
International Nuclear Information System (INIS)
Saddi, M.B.; Sandhu, B.S.; Singh, B.
2006-01-01
The phenomenon of double-photon Compton scattering has been successfully observed using a single γ detector, a technique avoiding the use of the complicated slow-fast coincidence set-up used till now for observing this higher-order process. Here doubly differential collision cross-sections integrated over the directions of one of the two final photons, the direction of other one being kept fixed, are measured experimentally for 0.662 MeV incident γ photons. The energy spectra of the detected photons are observed as a long tail to the single-photon Compton line on the lower side of the full energy peak in the recorded scattered energy spectrum. The present results are in agreement with theory of this process
Dose distribution in lungs and thyroid from scatter photons of x-ray mammography imaging
International Nuclear Information System (INIS)
Faghihi, R.; Mehdizadeh, S.
2006-01-01
The contribution of scatter photons in dose of mammography image in thyroid and lungs are studied. Thyroid and in the form of distribution function and total delivered dose studied by direct measurement with Thermoluminescence dosimeter. The results of measurements compared to other published measurements and the total dose compared to our modelling with Monte Carlo method.. Our phantoms for direct measurement of Dose are a compressed breast phantom placed on a female RANDO phantom. The results of modelling and measurement are in agreement for the total delivered dose to thyroid and lungs and comparable to doses reported by the other researcher
Hasell, D. K.; OLYMPUS Collaboration
2018-02-01
The OLYMPUS collaboration has recently made a precise measurement of the positron-proton to electron-proton elastic scattering cross section ratio, R 2γ, over a wide range of the virtual photon polarization, 0.456 reasonable agreement with predictions based on phenomenological fits to the available form factor data. The motivation for measuring R 2γ will be presented followed by a description of the OLYMPUS experiment. The importance of radiative corrections in the analysis will be shown also. Then we will present the OLYMPUS results and compare with results from two similar experiments and theoretical calculations.
International Nuclear Information System (INIS)
Meric, Ilker; Johansen, Geir A.
2013-01-01
In the petroleum industry precipitation of scale onto the inner walls of hydrocarbon pipelines poses a significant challenge as, unless treated appropriately, deposits such as sulfate and carbonate scales reduce the overall flow area and even lead to blockage of entire sections of the pipework. This may in turn result in costly production suspension and maintenance work. Therefore, monitoring and characterization of scale deposits can be said to be of great importance. In this work, a preliminary feasibility study is carried out in order to investigate the possibility of utilizing photon scattering for scale detection in multiphase oil/water/gas pipelines. (author)
Forward two-photon exchange in elastic lepton-proton scattering and hyperfine-splitting correction
Energy Technology Data Exchange (ETDEWEB)
Tomalak, Oleksandr [Johannes Gutenberg Universitaet, Institut fuer Kernphysik and PRISMA Cluster of Excellence, Mainz (Germany)
2017-08-15
We relate the forward two-photon exchange (TPE) amplitudes to integrals of the inclusive lepton-proton scattering cross sections. These relations yield an alternative way for the evaluation of the TPE correction to hyperfine-splitting (HFS) in the hydrogen-like atoms with an equivalent to the standard approach (Iddings, Drell and Sullivan) result implying the Burkhardt-Cottingham sum rule. For evaluation of the individual effects (e.g., elastic contribution) our approach yields a distinct result. We compare both methods numerically on examples of the elastic contribution and the full TPE correction to HFS in electronic and muonic hydrogen. (orig.)
Sentinel lymph node detection by an optical method using scattered photons
Tellier, Franklin; Ravelo, Rasata; Simon, Hervé; Chabrier, Renée; Steibel, Jérôme; Poulet, Patrick
2010-01-01
We present a new near infrared optical probe for the sentinel lymph node detection, based on the recording of scattered photons. A two wavelengths setup was developed to improve the detection threshold of an injected dye: the Patent Blue V dye. The method used consists in modulating each laser diode at a given frequency. A Fast Fourier Transform of the recorded signal separates both components. The signal amplitudes are used to compute relative Patent Blue V concentration. Results on the probe using phantoms model and small animal experimentation exhibit a sensitivity threshold of 3.2 µmol/L, which is thirty fold better than the eye visible threshold. PMID:21258517
From meson- and photon-nucleon scattering to vector mesons in nuclear matter
International Nuclear Information System (INIS)
Wolf, Gy.; Lutz, M.F.M.; Friman, B.
2003-01-01
A relativistic and unitary approach to pion- and photon-nucleon scattering taking into account the πN, ρN, ωN, ηN, πΔ, KΛ and KΣ channels is presented. The scheme dynamically generates the s- and d-wave baryon resonances N(1535), N(1650), N(1520) and N(1700) and as well as Δ(1620) and Δ(1700) in terms of quasi-local two-body interaction terms. A fair description of the experimental data relevant to the properties of slow vector mesons in nuclear matter is obtained. The resulting s-wave ρ- and ω-meson-nucleon scattering amplitudes which define the leading density modification of the ρ- and ω-meson spectral functions in nuclear matter are presented. (author)
Incoherent scattering of gamma photons for non-destructive tomographic inspection of pipeline
International Nuclear Information System (INIS)
Sharma, Amandeep; Sandhu, B.S.; Singh, Bhajan
2010-01-01
A scanner system, operating in a non-destructive and non-invasive way, is presented for pipeline to determine its location in land soil, wall thickness, type of liquid flowing and crack/blockage position. The present experiment simulates a real case where pipe corrosion (wall thinning) under insulation can be known from the study of incoherent scattering of 662 keV gamma photons. The incoherent scattered intensity, obtained by unfolding (deconvolution) the experimental pulse-height distribution of NaI(Tl) scintillation detector with the help of inverse response matrix, provides the desired information. The method is quite sensitive for small change (∼1 mm) in the thickness of pipe wall, locating a defect of 1 mm width under insulation and a small change (∼0.1 gm cm -3 ) in the density of liquid flowing through pipe.
Directory of Open Access Journals (Sweden)
Howell Rebecca M
2012-07-01
Full Text Available Abstract Background For many decades, the standard of care radiotherapy regimen for medulloblastoma has been photon (megavoltage x-rays craniospinal irradiation (CSI. The late effects associated with CSI are well-documented in the literature and are in-part attributed to unwanted dose to healthy tissue. Recently, there is growing interest in using proton therapy for CSI in pediatric and adolescent patients to reduce this undesirable dose. Previous comparisons of dose to target and non-target organs from conventional photon CSI and passively scattered proton CSI have been limited to small populations (n ≤ 3 and have not considered the use of age-dependent target volumes in proton CSI. Methods Standard of care treatment plans were developed for both photon and proton CSI for 18 patients. This cohort included both male and female medulloblastoma patients whose ages, heights, and weights spanned a clinically relevant and representative spectrum (age 2–16, BMI 16.4–37.9 kg/m2. Differences in plans were evaluated using Wilcoxon signed rank tests for various dosimetric parameters for the target volumes and normal tissue. Results Proton CSI improved normal tissue sparing while also providing more homogeneous target coverage than photon CSI for patients across a wide age and BMI spectrum. Of the 24 parameters (V5, V10, V15, and V20 in the esophagus, heart, liver, thyroid, kidneys, and lungs Wilcoxon signed rank test results indicated 20 were significantly higher for photon CSI compared to proton CSI (p ≤ 0.05 . Specifically, V15 and V20 in all six organs and V5, V10 in the esophagus, heart, liver, and thyroid were significantly higher with photon CSI. Conclusions Our patient cohort is the largest, to date, in which CSI with proton and photon therapies have been compared. This work adds to the body of literature that proton CSI reduces dose to normal tissue compared to photon CSI for pediatric patients who are at substantial risk for
International Nuclear Information System (INIS)
Howell, Rebecca M; Giebeler, Annelise; Koontz-Raisig, Wendi; Mahajan, Anita; Etzel, Carol J; D’Amelio, Anthony M Jr; Homann, Kenneth L
2012-01-01
For many decades, the standard of care radiotherapy regimen for medulloblastoma has been photon (megavoltage x-rays) craniospinal irradiation (CSI). The late effects associated with CSI are well-documented in the literature and are in-part attributed to unwanted dose to healthy tissue. Recently, there is growing interest in using proton therapy for CSI in pediatric and adolescent patients to reduce this undesirable dose. Previous comparisons of dose to target and non-target organs from conventional photon CSI and passively scattered proton CSI have been limited to small populations (n ≤ 3) and have not considered the use of age-dependent target volumes in proton CSI. Standard of care treatment plans were developed for both photon and proton CSI for 18 patients. This cohort included both male and female medulloblastoma patients whose ages, heights, and weights spanned a clinically relevant and representative spectrum (age 2–16, BMI 16.4–37.9 kg/m2). Differences in plans were evaluated using Wilcoxon signed rank tests for various dosimetric parameters for the target volumes and normal tissue. Proton CSI improved normal tissue sparing while also providing more homogeneous target coverage than photon CSI for patients across a wide age and BMI spectrum. Of the 24 parameters (V 5 , V 10 , V 15 , and V 20 in the esophagus, heart, liver, thyroid, kidneys, and lungs) Wilcoxon signed rank test results indicated 20 were significantly higher for photon CSI compared to proton CSI (p ≤ 0.05) . Specifically, V 15 and V 20 in all six organs and V 5 , V 10 in the esophagus, heart, liver, and thyroid were significantly higher with photon CSI. Our patient cohort is the largest, to date, in which CSI with proton and photon therapies have been compared. This work adds to the body of literature that proton CSI reduces dose to normal tissue compared to photon CSI for pediatric patients who are at substantial risk for developing radiogenic late effects. Although the present study
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
Scattering of Hawking photons as a barrier to particle absorption by black holes
International Nuclear Information System (INIS)
Funkhouser, Scott
2011-01-01
Electromagnetic scattering interactions between photons emanating from a Schwarzschild black hole and an incident charged particle should generate a repulsive force between the particle and black hole. The net scattering cross-section is calculated here as a function of the mass M of the black hole and the mass m of the particle for scenarios in which the particle is point-like and initially stationary, with proper energy ε=m, at some location far from the black hole. It follows from comparing the repulsive scattering force to the corresponding gravitational force that, in order for the particle to be drawn to the black hole, ε/T bh must be greater than a certain lower bound that is of the order 10 -3 for spin-1/2 or spin-0 particles with unit-charge. Although the scattering restriction is weaker than the requirement ε/T bh >>1 obtained independently from field-theoretic and thermodynamic treatments, the recurrence of a lower bound on the Boltzmann factor ε/T bh in limitations on particle absorption suggests a physical unity whose nature is fundamentally thermodynamic.
Compton scattering of photons from electrons in magnetically insulated transmission lines
International Nuclear Information System (INIS)
Brower, K.L.; VanDevender, J.P.
1979-01-01
Self-magnetically insulated transmission lines are used for power transport between the vacuum insulator and the diode in high current particle accelerators. Since the efficiency of the power transport depends on the details of the initial line geometry, i.e., the injector, the dependence of the electron canonical momentum distribution on the injector geometry should reveal the loss mechanism. We propose to study that dependence experimentally through a Compton scattering diagnostic. The spectrum of scattered light reveals the electron velocity distribution perpendicular to the direction of flow. The design of the diagnostic is in progress. Our preliminary analysis is based on the conservation of energy and canonical momentum for a single electron in the anti E and anti B fields determined from 2-D calculations. For the Mite accelerator with power flow along Z, the normalized canonical momentum, μ, is in the range - 0.7 < μ less than or equal to 0. For anti k/sub i/ parallel to circumflex Y, and anti k/sub s/ circumflex X, our analysis indicates that the scattered photons have 1.1 eV less than or equal to h nu/sub s/ < 5.6 eV for ruby laser scattering and can be detected with PM tubes
Low momentum transfer theorem for two photon exchange in lepton hardron scattering
International Nuclear Information System (INIS)
Penarrocha, J.A.; Bernabeu, J.
1981-01-01
The two photon contribution to lepton-hardon scattering is considered. Under the assumptions of Lorentz covarience, gauge invarience, unitarity, and analyticity, we prove a low momentum transfer theorem for the relevant amplitudes. Fixed energy dispersion relations tell us that their nonanalytic part, in the neighbourhood of t = 0, is given by the contribution of the two photon cut in the t-channel. The t-channel absorptive parts are obtained from unitarity. Their calculation has as input the two amplitudes corresponding to Compton scattering on the hadron with a pole contribution, and the continuum controlled at low t by the electromagnetic polarizabilities. By means of the dispersion integral, one proves the expansion k 1 (s)+k 2 (s)√-t+k 3 (s)tlog(-t)+O(t) for the continuum contribution, where k 1 (s) is the only unknown. Explicit expressions are obtained for the pole contribution as M→infinity, where M is the hadron mass, and for the continuum when (-t) 2 , where m is the muon mass and Λ is a characteristic parameter of the hadron structure
Mann, Nishan Singh
Photonic crystal waveguides (PCWs) are nano-scale devices offering an exciting platform for exploring and exploiting enhanced linear and nonlinear light-matter interactions, aided in-part by slowing down the group velocity (vg) of on-chip photons. However, with potential applications in telecommunications, bio-sensing and quantum computing, the road to commercialization and practical devices is hindered by our limited understanding of the influence of structural disorder on linear and nonlinear light propagation. This thesis refines and develops state-of-the-art mathematical and numerical models for understanding the important role of disorder-related optical phenomena for PCWs in the linear and optical nonlinear regime. The importance of Bloch modes is demonstrated by computing the power loss caused by disorder-induced scattering for various dispersion engineered PCWs. The theoretical results are found to be in very good agreement with related experiments and it is shown how dispersion engineered designs can minimize the Bloch fields around spatial imperfections resulting in a radical departure from the usual assumed scaling vg. -2 of backscatteringlosses. We also conduct a systematic investigation of the influence of intra-hole correlation length, a parameter characterizing disorder on backscattering losses and find the loss behaviour to be qualitatively dependent on waveguide design and frequency. We then model disorder-induced resonance shifts to compute the ensemble averaged disordered density of states, accounting for important local field effects which are crucial in achieving good qualitative agreement with experiments. Lastly, motivated by emerging experiments examining enhanced nonlinear interactions, we develop an intuitive time dependent coupled mode formalism to derive propagation equations describing nonlinear pulse propagation in the presence of disorder-induced multiple scattering. The framework establishes a natural length scale for each physical
Highly localized distributed Brillouin scattering response in a photonic integrated circuit
Directory of Open Access Journals (Sweden)
Atiyeh Zarifi
2018-03-01
Full Text Available The interaction of optical and acoustic waves via stimulated Brillouin scattering (SBS has recently reached on-chip platforms, which has opened new fields of applications ranging from integrated microwave photonics and on-chip narrow-linewidth lasers, to phonon-based optical delay and signal processing schemes. Since SBS is an effect that scales exponentially with interaction length, on-chip implementation on a short length scale is challenging, requiring carefully designed waveguides with optimized opto-acoustic overlap. In this work, we use the principle of Brillouin optical correlation domain analysis to locally measure the SBS spectrum with high spatial resolution of 800 μm and perform a distributed measurement of the Brillouin spectrum along a spiral waveguide in a photonic integrated circuit. This approach gives access to local opto-acoustic properties of the waveguides, including the Brillouin frequency shift and linewidth, essential information for the further development of high quality photonic-phononic waveguides for SBS applications.
Measurement of isolated photons accompained by jets in deep inelastic ep scattering
Energy Technology Data Exchange (ETDEWEB)
Abramowicz, H. [Tel Aviv Univ. (Israel). School of Physics; Max Planck Institute for Physics, Munich (Germany); Abt, I. [Max Planck Institute for Physics, Munich (Germany); Adamczyk, L. [AGH-Univ. of Science and Technology, Krakow (PL). Faculty of Physics and Applied Computer Science] (and others)
2012-06-15
The production of isolated high-energy photons accompanied by jets has been measured in deep inelastic ep scattering with the ZEUS detector at HERA, using an integrated luminosity of 326 pb{sup -1}. Measurements were made for exchanged photon virtualities, Q{sup 2}, in the range 10 to 350 GeV{sup 2}. The photons were measured in the transverse-energy and pseudorapidity ranges 4
Measurement of Isolated Photon Production in Deep-Inelastic Scattering at HERA
Aaron, F.D.; Alexa, C.; Andreev, V.; Antunovic, B.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Backovic, S.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Beckingham, M.; Begzsuren, K.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, N.; Bizot, J.C.; Boenig, M.O.; Boudry, V.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Bruncko, D.; Busser, F.W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Cantun Avila, K.B.; Cassol-Brunner, F.; 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 Roeck, A.; De Wolf, E.A.; Diaconu, C.; Dodonov, V.; Dubak, A.; Eckerlin, G.; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Eliseev, A.; Elsen, E.; Essenov, S.; Falkiewicz, A.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Finke, L.; Fleischer, M.; Fomenko, A.; Franke, G.; Frisson, T.; Gabathuler, E.; Gayler, J.; Ghazaryan, S.; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Gouzevitch, M.; Grab, C.; Greenshaw, T.; Grell, B.R.; Grindhammer, G.; Habib, S.; Haidt, D.; Hansson, M.; Heinzelmann, G.; Helebrant, C.; Henderson, R.C.W.; Henschel, H.; Herrera, G.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hreus, T.; Jacquet, M.; Janssen, M.E.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jung, A.W.; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I.R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knutsson, A.; Korbel, V.; Kostka, P.; Kraemer, M.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Kruger, K.; Landon, M.P.J.; Lange, W.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Li, G.; Lindfeld, L.; Lipka, K.; Liptaj, A.; List, B.; List, J.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.I.; Lytkin, L.; Makankine, A.; Malinovski, E.; Marage, P.; Marti, L.; Martisikova, M.; Martyn, H.U.; Maxfield, S.J.; Mehta, A.; Meier, K.; Meyer, A.B.; Meyer, H.; Meyer, H.; Meyer, J.; Michels, V.; Mikocki, S.; Milcewicz-Mika, I.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J.V.; Mozer, M.U.; Muller, K.; Murin, P.; Nankov, K.; Naroska, B.; Naumann, T.; Newman, P.R.; Niebuhr, C.; Nikiforov, A.; Nowak, G.; Nowak, K.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J.E.; Osman, S.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Pandurovic, M.; Papadopoulou, T.; Pascaud, C.; Patel, G.D.; Peng, H.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Picuric, I.; Piec, S.; Pitzl, D.; Placakyte, R.; Polifka, R.; Povh, B.; Preda, T.; Prideaux, P.; Radescu, V.; Rahmat, A.J.; Raicevic, N.; Ravdandorj, T.; Reimer, P.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Salek, D.; Salvaire, F.; Sankey, D.P.C.; Sauter, M.; Sauvan, E.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schoning, A.; Schultz-Coulon, H.C.; Sefkow, F.; Shaw-West, R.N.; Sheviakov, I.; Shtarkov, L.N.; Sloan, T.; Smiljanic, I.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, A.; Staykova, Z.; Steder, M.; Stella, B.; Stiewe, J.; 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.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, K.; Utkin, D.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Vinokurova, S.; Volchinski, V.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Wessels, M.; Wissing, C.; Wolf, R.; Wunsch, E.; Xella, S.; Yeganov, V.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y.C.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.
2008-01-01
The production of isolated photons in deep-inelastic scattering $ep\\to e \\gamma X$ is measured with the H1 detector at HERA. The measurement is performed in the kinematic range of negative four-momentum transfer squared $450$ GeV. The analysis is based on a total integrated luminosity of 227~pb$^{-1}$. The production cross section of isolatedphotons with a transverse energy in the range $3 < E_T^\\gamma < 10$ GeV and pseudorapidity range $-1.2 < \\eta^\\gamma < 1.8$ is measured as a function of $E_T^\\gamma$, $\\eta^\\gamma$ and $Q^2$. Isolated photon cross sections are also measured for events with no jets or at least one hadronic jet. The measurements are compared with predictions from Monte Carlo generators modelling the photon radiation from the quark and the electron lines, as well as with calculations at leading and next to leading order in the strong coupling. The predictions significantly underestimate the measured cross sections.
Mann, Kulwinder Singh
2018-01-01
Scattered photon's influence on measured values of attenuation coefficients (μm, cm2g-1) for six low-Z (effective atomic number) building materials, at three photon energies has been estimated. Narrow-beam transmission geometry has been used for the measurements. Samples of commonly used engineering materials (Cements, Clay, Lime-Stone, Plaster of Paris) have been selected for the present study. Standard radioactive sources Cs137 and Co60 have been used for obtaining γ-ray energies 661.66, 1173.24 and 1332.50 keV. The optical thickness (OT) of 0.5 mfp (mean free path) has been found the optimum optical thickness (OOT) for μm-measurement in the selected energy range (661.66-1332.50 keV). The aim of this investigation is to provide neglected information regarding subsistence of scattered photons in narrow beam geometry measurements for low-Z materials. The measurements have been performed for a wide range of sample-thickness (2-26 cm) such that their OT varies between 0.2-3.5 mfp in selected energy range. A computer program (GRIC2-toolkit) has been used for various theoretical computations required in this investigation. It has been concluded that in selected energy-range, good accuracy in μm-measurement of low-Z materials can be achieved by keeping their sample's OT below 0.5 mfp. The exposure buildup factors have been measured with the help of mathematical-model developed in this investigation.
Energy Technology Data Exchange (ETDEWEB)
Amusia, Miron [Hebrew Univ., Jerusalem (Israel). Racah Inst. of Physics; Ioffe Physico-Technical Inst., St. Petersburg (Russian Federation); Chernysheva, Larissa [Ioffe Physico-Technical Inst., St. Petersburg (Russian Federation); Yarzhemsky, Victor [Kurnakov Institute of General and Inorganic Chemistry, Moscow (Russian Federation)
2012-07-01
The aim of this book is to present highly accurate and extensive theoretical Atomic data and to give a survey of selected calculational methods for atomic physics, used to obtain these data. The book presents the results of calculations of cross sections and probabilities of a broad variety of atomic processes with participation of photons and electrons, namely on photoabsorption, electron scattering and accompanying effects. Included are data for photoabsorption and electron scattering cross-sections and probabilities of vacancy decay formed for a large number of atoms and ions. Attention is also given to photoionization and vacancy decay in endohedrals and to positron-atom scattering. The book is richly illustrated. The methods used are one-electron Hartree-Fock and the technique of Feynman diagrams that permits to include many-electron correlations. This is done in the frames of the Random Phase approximation with exchange and the many-body perturbation theory. Newly obtained and previously collected atomic data are presented. The atomic data are useful for investigating the electronic structure and physical processes in solids and liquids, molecules and clusters, astronomical objects, solar and planet atmospheres and atomic nucleus. Deep understanding of chemical reactions and processes is reached by deep and accurate knowledge of atomic structure and processes with participation of atoms. This book is useful for theorists performing research in different domains of contemporary physics, chemistry and biology, technologists working on production of new materials and for experimentalists performing research in the field of photon and electron interaction with atoms, molecules, solid bodies and liquids.
Energy Technology Data Exchange (ETDEWEB)
Garvey, G.T., E-mail: garvey@lanl.gov [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545 (United States); Harris, D.A., E-mail: dharris@fnal.gov [Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL, 60510-5011 (United States); Tanaka, H.A., E-mail: tanaka@phas.ubc.ca [Institute of Particle Physics and Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); Tayloe, R., E-mail: rtayloe@indiana.edu [Department of Physics, Indiana University, 727 E. Third St., Bloomington, IN 47405-7105 (United States); Zeller, G.P., E-mail: gzeller@fnal.gov [Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL, 60510-5011 (United States)
2015-06-15
The study of neutrino–nucleus interactions has recently seen rapid development with a new generation of accelerator-based neutrino experiments employing medium and heavy nuclear targets for the study of neutrino oscillations. A few unexpected results in the study of quasi-elastic scattering and single photon production have spurred a revisiting of the underlying nuclear physics and connections to electron–nucleus scattering. A thorough understanding and resolution of these issues is essential for future progress in the study of neutrino oscillations. A recent workshop hosted by the Institute of Nuclear Theory at the University of Washington (INT-13-54W) examined experimental and theoretical developments in neutrino–nucleus interactions and related measurements from electron and pion scattering. We summarize the discussions at the workshop pertaining to the aforementioned issues in quasi-elastic scattering and single photon production, particularly where there was consensus on the highest priority issues to be resolved and the path towards resolving them.
Systematic and robust design of photonic crystal waveguides by topology optimization
DEFF Research Database (Denmark)
Wang, Fengwen; Jensen, Jakob Søndergaard; Sigmund, Ole
2010-01-01
on a threshold projection. The objective is formulated to minimize the maximum error between actual group indices and a prescribed group index among these three designs. Novel photonic crystal waveguide facilitating slow light with a group index of n(g) = 40 is achieved by the robust optimization approach......A robust topology optimization method is presented to consider manufacturing uncertainties in tailoring dispersion properties of photonic crystal waveguides. The under, normal and over-etching scenarios in manufacturing process are represented by dilated, intermediate and eroded designs based....... The numerical result illustrates that the robust topology optimization provides a systematic and robust design methodology for photonic crystal waveguide design....
Systematic trends in photonic reagent induced reactions in a homologous chemical family.
Tibbetts, Katharine Moore; Xing, Xi; Rabitz, Herschel
2013-08-29
The growing use of ultrafast laser pulses to induce chemical reactions prompts consideration of these pulses as "photonic reagents" in analogy to chemical reagents. This work explores the prospect that photonic reagents may affect systematic trends in dissociative ionization reactions of a homologous family of halomethanes, much as systematic outcomes are often observed for reactions between homologous families of chemical reagents and chemical substrates. The experiments in this work with photonic reagents of varying pulse energy and linear spectral chirp reveal systematic correlations between observable ion yields and the following set of natural variables describing the substrate molecules: the ionization energy of the parent molecule, the appearance energy of each fragment ion, and the relative strength of carbon-halogen bonds in molecules containing two different halogens. The results suggest that reactions induced by photonic reagents exhibit systematic behavior analogous to that observed in reactions driven by chemical reagents, which provides a basis to consider empirical "rules" for predicting the outcomes of photonic reagent induced reactions.
Directory of Open Access Journals (Sweden)
Annepu Venkata Naga Vamsi
2016-01-01
Full Text Available We have reported the measurement of temperature by using coherent anti-Stroke and coherent Stroke Raman scattering using superconducting nano wire single-photon detector. The measured temperatures by both methods (Coherent Anti-Raman scattering & Coherent Stroke Raman scattering and TC 340 are in good accuracy of ± 5 K temperature range. The length of the pipe line under test can be increased by increasing the power of the pump laser. This methodology can be widely used to measure temperatures at instantaneous positions in test pipe line or the entire temperature of the pipe line under test.
First measurement of $Z/\\gamma^{*}$ production in Compton scattering of quasi-real photons
Abbiendi, G.; Alexander, G.; Allison, John; Altekamp, N.; Anderson, K.J.; Anderson, S.; Arcelli, S.; Asai, S.; Ashby, S.F.; Axen, D.; Azuelos, G.; Ball, A.H.; Barberio, E.; Barlow, Roger J.; Bartoldus, R.; Batley, J.R.; Baumann, S.; Bechtluft, J.; Behnke, T.; Bell, Kenneth Watson; Bella, G.; Bellerive, A.; Bentvelsen, S.; Bethke, S.; Betts, S.; Biebel, O.; Biguzzi, A.; Bird, S.D.; Blobel, V.; Bloodworth, I.J.; Bobinski, M.; Bock, P.; Bohme, J.; Bonacorsi, D.; Boutemeur, M.; Braibant, S.; Bright-Thomas, P.; Brigliadori, L.; Brown, Robert M.; Burckhart, H.J.; Burgard, C.; Burgin, R.; Capiluppi, P.; Carnegie, R.K.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, David G.; Chrisman, D.; Ciocca, C.; Clarke, P.E.L.; Clay, E.; Cohen, I.; Conboy, J.E.; Cooke, O.C.; Couyoumtzelis, C.; Coxe, R.L.; Cuffiani, M.; Dado, S.; Dallavalle, G.Marco; Davis, R.; De Jong, S.; del Pozo, L.A.; De Roeck, A.; Desch, K.; Dienes, B.; Dixit, M.S.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Eatough, D.; Estabrooks, P.G.; Etzion, E.; Evans, H.G.; Fabbri, F.; Fanti, M.; Faust, A.A.; Fiedler, F.; Fierro, M.; Fleck, I.; Folman, R.; Furtjes, A.; Futyan, D.I.; Gagnon, P.; Gary, J.W.; Gascon, J.; Gascon-Shotkin, S.M.; Gaycken, G.; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Gibson, V.; Gibson, W.R.; Gingrich, D.M.; Glenzinski, D.; Goldberg, J.; Gorn, W.; Grandi, C.; Gross, E.; Grunhaus, J.; Gruwe, M.; Hanson, G.G.; Hansroul, M.; Hapke, M.; Harder, K.; Hargrove, C.K.; Hartmann, C.; Hauschild, M.; Hawkes, C.M.; Hawkings, R.; Hemingway, R.J.; Herndon, M.; Herten, G.; Heuer, R.D.; Hildreth, M.D.; Hill, J.C.; Hillier, S.J.; Hobson, P.R.; Hocker, James Andrew; Homer, R.J.; Honma, A.K.; Horvath, D.; Hossain, K.R.; Howard, R.; Huntemeyer, P.; Igo-Kemenes, P.; Imrie, D.C.; Ishii, K.; Jacob, F.R.; Jawahery, A.; Jeremie, H.; Jimack, M.; Jones, C.R.; Jovanovic, P.; Junk, T.R.; Karlen, D.; Kartvelishvili, V.; Kawagoe, K.; Kawamoto, T.; Kayal, P.I.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Klier, A.; Kluth, S.; Kobayashi, T.; Kobel, M.; Koetke, D.S.; Kokott, T.P.; Kolrep, M.; Komamiya, S.; Kowalewski, Robert V.; Kress, T.; Krieger, P.; von Krogh, J.; Kuhl, T.; Kyberd, P.; Lafferty, G.D.; Lanske, D.; Lauber, J.; Lautenschlager, S.R.; Lawson, I.; Layter, J.G.; Lazic, D.; Lee, A.M.; Lellouch, D.; Letts, J.; Levinson, L.; Liebisch, R.; List, B.; Littlewood, C.; Lloyd, A.W.; Lloyd, S.L.; Loebinger, F.K.; Long, G.D.; Losty, M.J.; Ludwig, J.; Lui, D.; Macchiolo, A.; Macpherson, A.; Mader, W.; Mannelli, M.; Marcellini, S.; Markopoulos, C.; Martin, A.J.; Martin, J.P.; Martinez, G.; Mashimo, T.; Mattig, Peter; McDonald, W.John; McKenna, J.; Mckigney, E.A.; McMahon, T.J.; McPherson, R.A.; Meijers, F.; Menke, S.; Merritt, F.S.; Mes, H.; Meyer, J.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Mir, R.; Mohr, W.; Montanari, A.; Mori, T.; Nagai, K.; Nakamura, I.; Neal, H.A.; Nellen, B.; Nisius, R.; O'Neale, S.W.; Oakham, F.G.; Odorici, F.; Ogren, H.O.; Oreglia, M.J.; Orito, S.; Palinkas, J.; Pasztor, G.; Pater, J.R.; Patrick, G.N.; Patt, J.; Perez-Ochoa, R.; Petzold, S.; Pfeifenschneider, P.; Pilcher, J.E.; Pinfold, J.; Plane, David E.; Poffenberger, P.; Polok, J.; Przybycien, M.; Rembser, C.; Rick, H.; Robertson, S.; Robins, S.A.; Rodning, N.; Roney, J.M.; Roscoe, K.; Rossi, A.M.; Rozen, Y.; Runge, K.; Runolfsson, O.; Rust, D.R.; Sachs, K.; Saeki, T.; Sahr, O.; Sang, W.M.; Sarkisian, E.K.G.; Sbarra, C.; Schaile, A.D.; Schaile, O.; Scharf, F.; Scharff-Hansen, P.; Schieck, J.; Schmitt, B.; Schmitt, S.; Schoning, A.; Schroder, Matthias; Schumacher, M.; Schwick, C.; Scott, W.G.; Seiler, T.; Seuster, R.; Shears, T.G.; Shen, B.C.; Shepherd-Themistocleous, C.H.; Sherwood, P.; Siroli, G.P.; Sittler, A.; Skuja, A.; Smith, A.M.; Snow, G.A.; Sobie, R.; Soldner-Rembold, S.; Sproston, M.; Stahl, A.; Stephens, K.; Steuerer, J.; Stoll, K.; Strom, David M.; Strohmer, R.; Surrow, B.; Talbot, S.D.; Tanaka, S.; Taras, P.; Tarem, S.; Teuscher, R.; Thiergen, M.; Thomson, M.A.; von Torne, E.; Torrence, E.; Towers, S.; Trigger, I.; Trocsanyi, Z.; Tsur, E.; Turcot, A.S.; Turner-Watson, M.F.; Van Kooten, Rick J.; Vannerem, P.; Verzocchi, M.; Voss, H.; Wackerle, F.; Wagner, A.; Ward, C.P.; Ward, D.R.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wermes, N.; White, J.S.; Wilson, G.W.; Wilson, J.A.; Wyatt, T.R.; Yamashita, S.; Yekutieli, G.; Zacek, V.; Zer-Zion, D.
1998-01-01
We report the first observation of Z/gamma* production in Compton scattering of quasi-real photons. This is a subprocess of the reaction e+e- to e+e-Z/gamma*, where one of the final state electrons is undetected. Approximately 55 pb-1 of data collected in the year 1997 at an e+e- centre-of-mass energy of 183 GeV with the OPAL detector at LEP have been analysed. The Z/gamma* from Compton scattering has been detected in the hadronic decay channel. Within well defined kinematic bounds, we measure the product of cross-section and Z/gamma* branching ratio to hadrons to be (0.9+-0.3+-0.1) pb for events with a hadronic mass larger than 60 GeV, dominated by (e)eZ production. In the hadronic mass region between 5 GeV and 60 GeV, dominated by (e)egamma* production, this product is found to be (4.1+-1.6+-0.6) pb. Our results agree with the predictions of two Monte Carlo event generators, grc4f and PYTHIA.
Chen, Yuntian; Zhang, Yan; Femius Koenderink, A
2017-09-04
We study semi-analytically the light emission and absorption properties of arbitrary stratified photonic structures with embedded two-dimensional magnetoelectric point scattering lattices, as used in recent plasmon-enhanced LEDs and solar cells. By employing dyadic Green's function for the layered structure in combination with the Ewald lattice summation to deal with the particle lattice, we develop an efficient method to study the coupling between planar 2D scattering lattices of plasmonic, or metamaterial point particles, coupled to layered structures. Using the 'array scanning method' we deal with localized sources. Firstly, we apply our method to light emission enhancement of dipole emitters in slab waveguides, mediated by plasmonic lattices. We benchmark the array scanning method against a reciprocity-based approach to find that the calculated radiative rate enhancement in k-space below the light cone shows excellent agreement. Secondly, we apply our method to study absorption-enhancement in thin-film solar cells mediated by periodic Ag nanoparticle arrays. Lastly, we study the emission distribution in k-space of a coupled waveguide-lattice system. In particular, we explore the dark mode excitation on the plasmonic lattice using the so-called array scanning method. Our method could be useful for simulating a broad range of complex nanophotonic structures, i.e., metasurfaces, plasmon-enhanced light emitting systems and photovoltaics.
Mohammadi, S. M.; Tavakoli-Anbaran, H.; Zeinali, H. Z.
2017-02-01
The parallel-plate free-air ionization chamber termed FAC-IR-300 was designed at the Atomic Energy Organization of Iran, AEOI. This chamber is used for low and medium X-ray dosimetry on the primary standard level. In order to evaluate the air-kerma, some correction factors such as electron-loss correction factor (ke) and photon scattering correction factor (ksc) are needed. ke factor corrects the charge loss from the collecting volume and ksc factor corrects the scattering of photons into collecting volume. In this work ke and ksc were estimated by Monte Carlo simulation. These correction factors are calculated for mono-energy photon. As a result of the simulation data, the ke and ksc values for FAC-IR-300 ionization chamber are 1.0704 and 0.9982, respectively.
International Nuclear Information System (INIS)
Mohammadi, S.M.; Tavakoli-Anbaran, H.; Zeinali, H.Z.
2017-01-01
The parallel-plate free-air ionization chamber termed FAC-IR-300 was designed at the Atomic Energy Organization of Iran, AEOI. This chamber is used for low and medium X-ray dosimetry on the primary standard level. In order to evaluate the air-kerma, some correction factors such as electron-loss correction factor (k e ) and photon scattering correction factor (k sc ) are needed. k e factor corrects the charge loss from the collecting volume and k sc factor corrects the scattering of photons into collecting volume. In this work k e and k sc were estimated by Monte Carlo simulation. These correction factors are calculated for mono-energy photon. As a result of the simulation data, the k e and k sc values for FAC-IR-300 ionization chamber are 1.0704 and 0.9982, respectively.
Local Two-Photon Couplings and the J=0 Fixed Pole in Real and Virtual Compton Scattering
Energy Technology Data Exchange (ETDEWEB)
Brodsky, Stanley J.; Llanes-Estrada, Felipe J.; Szczepaniak, Adam P.
2008-12-05
The local coupling of two photons to the fundamental quark currents of a hadron gives an energy-independent contribution to the Compton amplitude proportional to the charge squared of the struck quark, a contribution which has no analog in hadron scattering reactions. We show that this local contribution has a real phase and is universal, giving the same contribution for real or virtual Compton scattering for any photon virtuality and skewness at fixed momentum transfer squared t. The t-dependence of this J = 0 fixed Regge pole is parameterized by a yet unmeasured even charge-conjugation form factor of the target nucleon. The t = 0 limit gives an important constraint on the dependence of the nucleon mass on the quark mass through the Weisberger relation. We discuss how this 1=x form factor can be extracted from high energy deeply virtual Compton scattering and examine predictions given by models of the H generalized parton distribution.
Andrews, David L
2015-01-01
Discusses the basic physical principles underlying Biomedical Photonics, spectroscopy and microscopy This volume discusses biomedical photonics, spectroscopy and microscopy, the basic physical principles underlying the technology and its applications. The topics discussed in this volume are: Biophotonics; Fluorescence and Phosphorescence; Medical Photonics; Microscopy; Nonlinear Optics; Ophthalmic Technology; Optical Tomography; Optofluidics; Photodynamic Therapy; Image Processing; Imaging Systems; Sensors; Single Molecule Detection; Futurology in Photonics. Comprehensive and accessible cov
Andrews, David L
2015-01-01
Discusses the basic physical principles underlying the technology instrumentation of photonics This volume discusses photonics technology and instrumentation. The topics discussed in this volume are: Communication Networks; Data Buffers; Defense and Security Applications; Detectors; Fiber Optics and Amplifiers; Green Photonics; Instrumentation and Metrology; Interferometers; Light-Harvesting Materials; Logic Devices; Optical Communications; Remote Sensing; Solar Energy; Solid-State Lighting; Wavelength Conversion Comprehensive and accessible coverage of the whole of modern photonics Emphas
Andrews, David L
2015-01-01
Discusses the basic physical principles underlying thescience and technology of nanophotonics, its materials andstructures This volume presents nanophotonic structures and Materials.Nanophotonics is photonic science and technology that utilizeslight/matter interactions on the nanoscale where researchers arediscovering new phenomena and developing techniques that go wellbeyond what is possible with conventional photonics andelectronics.The topics discussed in this volume are: CavityPhotonics; Cold Atoms and Bose-Einstein Condensates; Displays;E-paper; Graphene; Integrated Photonics; Liquid Cry
Andrews, David L
2015-01-01
This book covers modern photonics accessibly and discusses the basic physical principles underlying all the applications and technology of photonicsThis volume covers the basic physical principles underlying the technology and all applications of photonics from statistical optics to quantum optics. The topics discussed in this volume are: Photons in perspective; Coherence and Statistical Optics; Complex Light and Singular Optics; Electrodynamics of Dielectric Media; Fast and slow Light; Holography; Multiphoton Processes; Optical Angular Momentum; Optical Forces, Trapping and Manipulation; Pol
Systematics of elastic scattering at high and intermediate energy
Energy Technology Data Exchange (ETDEWEB)
Dias De Deus, J [Instituto de Fisica e Matematica, Lisboa (Portugal); Kroll, P [Wuppertal Univ. (Gesamthochschule) (Germany, F.R.)
1977-01-01
A model for elastic scattering valid in the intermediate and high-energy region is proposed. The model includes three kinds of entities: the pomeron, a universal GS pomeron; the reggeons, also universal and of GS type; and the core, a low-energy central real piece required by dispersion relations. The number of free functions and parameters is rather small. The approach supports naive duality and, in general, agrees with the results of absorptive models.
Maksimenko, V. V.; Zagaynov, V. A.; Agranovski, I. E.
2013-11-01
It is shown that complexities in a problem of elastic scattering of a photon on a pair of Rayleigh particles (two small metallic spheres) are similar to the complexities of the classic problem of three bodies in celestial mechanics. In the latter problem, as is well known, the phase trajectory of a system becomes a nonanalytical function of its variables. In our problem, the trajectory of a virtual photon at some frequency could be considered such as the well-known Antoine set (Antoine's necklace) or a chain with interlaced sections having zero topological dimension and fractal structure. Such a virtual “zero-dimensional” photon could be localized between the particles of the pair. The topology suppresses the photon's exit to the real world with dimensional equal-to-or-greater-than units. The physical reason for this type of photon localization is related to the “mechanical rigidity” of interlaced sections of the photon trajectory due to a singularity of energy density along these sections. Within the approximations used in this paper, the effect is possible if the frequency of the incident radiation is equal to double the frequency of the dipole surface plasmon in an isolated particle, which is the only character frequency in the problem. This condition and transformation of the photon trajectory to the zero-dimensional Antoine set reminds of some of the simplest variants of Poincaré's catastrophe in the dynamics of some nonintegrable systems. The influence of the localization on elastic light scattering by the pair is investigated.
Tiwari, Vidhu S.; Khetani, Altaf; Monfared, Ali Momenpour T.; Smith, Brett; Anis, Hanan; Trudeau, Vance L.
2012-03-01
The present work explores the feasibility of using surface enhanced Raman scattering (SERS) for detecting the neurotransmitters such as glutamate (GLU) and gamma-amino butyric acid (GABA). These amino acid neurotransmitters that respectively mediate fast excitatory and inhibitory neurotransmission in the brain, are important for neuroendocrine control, and upsets in their synthesis are also linked to epilepsy. Our SERS-based detection scheme enabled the detection of low amounts of GLU (10-7 M) and GABA (10-4 M). It may complement existing techniques for characterizing such kinds of neurotransmitters that include high-performance liquid chromatography (HPLC) or mass spectrography (MS). This is mainly because SERS has other advantages such as ease of sample preparation, molecular specificity and sensitivity, thus making it potentially applicable to characterization of experimental brain extracts or clinical diagnostic samples of cerebrospinal fluid and saliva. Using hollow core photonic crystal fiber (HC-PCF) further enhanced the Raman signal relative to that in a standard cuvette providing sensitive detection of GLU and GABA in micro-litre volume of aqueous solutions.
Li, Pengcheng; Liu, Celong; Li, Xianpeng; He, Honghui; Ma, Hui
2016-09-20
In earlier studies, we developed scattering models and the corresponding CPU-based Monte Carlo simulation programs to study the behavior of polarized photons as they propagate through complex biological tissues. Studying the simulation results in high degrees of freedom that created a demand for massive simulation tasks. In this paper, we report a parallel implementation of the simulation program based on the compute unified device architecture running on a graphics processing unit (GPU). Different schemes for sphere-only simulations and sphere-cylinder mixture simulations were developed. Diverse optimizing methods were employed to achieve the best acceleration. The final-version GPU program is hundreds of times faster than the CPU version. Dependence of the performance on input parameters and precision were also studied. It is shown that using single precision in the GPU simulations results in very limited losses in accuracy. Consumer-level graphics cards, even those in laptop computers, are more cost-effective than scientific graphics cards for single-precision computation.
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
Energy Technology Data Exchange (ETDEWEB)
Garvey, G. T. [Los Alamos; Harris, D. A. [Fermilab; Tanaka, H. A. [British Columbia U.; Tayloe, R. [Indiana U.; Zeller, G. P. [Fermilab
2015-06-15
The study of neutrino–nucleus interactions has recently seen rapid development with a new generation of accelerator-based neutrino experiments employing medium and heavy nuclear targets for the study of neutrino oscillations. A few unexpected results in the study of quasi-elastic scattering and single photon production have spurred a revisiting of the underlying nuclear physics and connections to electron–nucleus scattering. A thorough understanding and resolution of these issues is essential for future progress in the study of neutrino oscillations.
International Nuclear Information System (INIS)
Furtak, T.E.
1982-01-01
Photon spectroscopic techniques are being developed as tools with which to study fundamental and applied problems associated with the composition, structure, and evolution of the metal-electrolyte interface. The main research is built around surface enhanced Raman scattering with differential reflectance and photo-voltage spectroscopy as supplementary techniques. All of these techniques are used in situ while the sample is exposed to the electrochemical environment of interest
Energy Technology Data Exchange (ETDEWEB)
Song, Guo-Zhu; Zhang, Mei; Ai, Qing; Yang, Guo-Jian [Department of Physics, Applied Optics Beijing Area Major Laboratory, Beijing Normal University, Beijing 100875 (China); Alsaedi, Ahmed; Hobiny, Aatef [NAAM-Research Group, Department of Mathematics, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia); Deng, Fu-Guo, E-mail: fgdeng@bnu.edu.cn [Department of Physics, Applied Optics Beijing Area Major Laboratory, Beijing Normal University, Beijing 100875 (China); NAAM-Research Group, Department of Mathematics, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia)
2017-03-15
We propose a heralded quantum repeater based on the scattering of photons off single emitters in one-dimensional waveguides. We show the details by implementing nonlocal entanglement generation, entanglement swapping, and entanglement purification modules with atoms in waveguides, and discuss the feasibility of the repeater with currently achievable technology. In our scheme, the faulty events can be discarded by detecting the polarization of the photons. That is, our protocols are accomplished with a fidelity of 100% in principle, which is advantageous for implementing realistic long-distance quantum communication. Moreover, additional atomic qubits are not required, but only a single-photon medium. Our scheme is scalable and attractive since it can be realized in solid-state quantum systems. With the great progress on controlling atom-waveguide systems, the repeater may be very useful in quantum information processing in the future.
International Nuclear Information System (INIS)
Perina, Jan Jr.; Sibilia, Concita; Tricca, Daniela; Bertolotti, Mario
2005-01-01
Optical parametric process occurring in a nonlinear planar waveguide can serve as a source of light with nonclassical properties. The properties of the generated fields are substantially modified by scattering of the nonlinearly interacting fields in a photonic-band-gap structure inside the waveguide. A general quantum model of linear operator amplitude corrections to the amplitude mean values and its numerical analysis provide conditions for efficient squeezed-light generation as well as generation of light with sub-Poissonian photon-number statistics. The destructive influence of phase mismatch of the nonlinear interaction can fully be compensated using a suitable photonic-band-gap structure inside the waveguide. Also an increase of the signal-to-noise ratio of the incident optical field can be reached in the waveguide
International Nuclear Information System (INIS)
Gakh, G.I.; Tomasi-Gustafsson, E.
2006-01-01
The general spin structure of the matrix element, taking into account the 2-photon exchange contribution, for the elastic electron (positron) - deuteron scattering has been derived using general symmetry properties of the hadron electromagnetic interaction, such as P-, C- and T-invariances as well as lepton helicity conservation in QED at high energy. Taking into account also crossing symmetry, the amplitudes of e ± d scattering can be parametrized in terms of fifteen real functions. The expressions for the differential cross section and for all polarization observables are given in terms of these functions. We consider the case of an arbitrary polarized deuteron target and polarized electron beam (both longitudinal and transverse). The transverse polarization of the electron beam induces a single-spin asymmetry which is non-zero in presence of 2-photon exchange. It is shown that elastic deuteron electromagnetic form factors can still be extracted in presence of 2 photon exchange, from the measurements of the differential cross sections and of one polarization observable (for example, the tensor asymmetry) for electron and positron deuteron elastic scattering, in the same kinematical conditions. (authors)
Quantum scattering theory of a single-photon Fock state in three-dimensional spaces.
Liu, Jingfeng; Zhou, Ming; Yu, Zongfu
2016-09-15
A quantum scattering theory is developed for Fock states scattered by two-level systems in three-dimensional free space. It is built upon the one-dimensional scattering theory developed in waveguide quantum electrodynamics. The theory fully quantizes the incident light as Fock states and uses a non-perturbative method to calculate the scattering matrix.
International Nuclear Information System (INIS)
Wegmann, K.; Brix, G.
2000-01-01
Purpose: Single photon transmission (SPT) measurements offer a new approach for the determination of attenuation correction factors (ACF) in PET. It was the aim of the present work, to evaluate a scatter correction alogrithm proposed by C. Watson by means of Monte Carlo simulations. Methods: SPT measurements with a Cs-137 point source were simulated for a whole-body PET scanner (ECAT EXACT HR + ) in both the 2D and 3D mode. To examine the scatter fraction (SF) in the transmission data, the detected photons were classified as unscattered or scattered. The simulated data were used to determine (i) the spatial distribution of the SFs, (ii) an ACF sinogram from all detected events (ACF tot ) and (iii) from the unscattered events only (ACF unscattered ), and (iv) an ACF cor =(ACF tot ) 1+Κ sinogram corrected according to the Watson algorithm. In addition, density images were reconstructed in order to quantitatively evaluate linear attenuation coefficients. Results: A high correlation was found between the SF and the ACF tot sinograms. For the cylinder and the EEC phantom, similar correction factors Κ were estimated. The determined values resulted in an accurate scatter correction in both the 2D and 3D mode. (orig.) [de
On the effects of systematic errors in analysis of nuclear scattering data
International Nuclear Information System (INIS)
Bennett, M.T.; Steward, C.; Amos, K.; Allen, L.J.
1995-01-01
The effects of systematic errors on elastic scattering differential cross-section data upon the assessment of quality fits to that data have been studied. Three cases are studied, namely the differential cross-section data sets from elastic scattering of 200 MeV protons from 12 C, of 350 MeV 16 O- 16 O scattering and of 288.6 MeV 12 C- 12 C scattering. First, to estimate the probability of any unknown systematic errors, select sets of data have been processed using the method of generalized cross validation; a method based upon the premise that any data set should satisfy an optimal smoothness criterion. In another case, the S function that provided a statistically significant fit to data, upon allowance for angle variation, became overdetermined. A far simpler S function form could then be found to describe the scattering process. The S functions so obtained have been used in a fixed energy inverse scattering study to specify effective, local, Schroedinger potentials for the collisions. An error analysis has been performed on the results to specify confidence levels for those interactions. 19 refs., 6 tabs., 15 figs
Li, Ming
In this dissertation, a set of numerical simulation tools are developed under previous work to efficiently and accurately study one-dimensional (1D), two-dimensional (2D), 2D slab and three-dimensional (3D) photonic crystal structures and their defects effects by means of spectrum (transmission, reflection, absorption), band structure (dispersion relation), and electric and/or magnetic fields distribution (mode profiles). Further more, the lasing property and spontaneous emission behaviors are studied when active gain materials are presented in the photonic crystal structures. First, the planewave based transfer (scattering) matrix method (TMM) is described in every detail along with a brief review of photonic crystal history (Chapter 1 and 2). As a frequency domain method, TMM has the following major advantages over other numerical methods: (1) the planewave basis makes Maxwell's Equations a linear algebra problem and there are mature numerical package to solve linear algebra problem such as Lapack and Scalapack (for parallel computation). (2) Transfer (scattering) matrix method make 3D problem into 2D slices and link all slices together via the scattering matrix (S matrix) which reduces computation time and memory usage dramatically and makes 3D real photonic crystal devices design possible; and this also makes the simulated domain no length limitation along the propagation direction (ideal for waveguide simulation). (3) It is a frequency domain method and calculation results are all for steady state, without the influences of finite time span convolution effects and/or transient effects. (4) TMM can treat dispersive material (such as metal at visible light) naturally without introducing any additional computation; and meanwhile TMM can also deal with anisotropic material and magnetic material (such as perfectly matched layer) naturally from its algorithms. (5) Extension of TMM to deal with active gain material can be done through an iteration procedure with gain
Qattan, I. A.
2017-06-01
I present a prediction of the e± elastic scattering cross-section ratio, Re+e-, as determined using a new parametrization of the two-photon exchange (TPE) corrections to electron-proton elastic scattering cross section σR. The extracted ratio is compared to several previous phenomenological extractions, TPE hadronic calculations, and direct measurements from the comparison of electron and positron scattering. The TPE corrections and the ratio Re+e- show a clear change of sign at low Q2, which is necessary to explain the high-Q2 form factors discrepancy while being consistent with the known Q2→0 limit. While my predictions are in generally good agreement with previous extractions, TPE hadronic calculations, and existing world data including the recent two measurements from the CLAS and VEPP-3 Novosibirsk experiments, they are larger than the new OLYMPUS measurements at larger Q2 values.
International Nuclear Information System (INIS)
Patterson, M; Hughes, S
2010-01-01
We introduce a theoretical formalism to describe disorder-induced extrinsic scattering in slow light photonic crystal waveguides. This work details and extends the optical scattering theory used in a recent issue of Physics Review Letters (Patterson et al 2009 Phys. Rev. Lett. 102 253903) to describe coherent scattering phenomena and successfully explain related experimental measurements. Our presented theory, which combines Green function and coupled mode methods, allows us to self-consistently account for arbitrary multiple scattering for the propagating electric field and recover experimental features such as resonances near the band edge. The technique is fully three-dimensional and can calculate the effects of disorder on the propagating field over thousands of unit cells. As an application of this theory, we explore various sample lengths and disordered instances, and demonstrate the profound effect of multiple scattering in the waveguide transmission. The spectra yield rich features associated with disorder-induced localization and multiple scattering, which are shown to be exacerbated in the slow light propagation regime
2002-01-01
This experiment will investigate various aspects of photon-parton scattering and will be performed in the H2 beam of the SPS North Area with high intensity hadron beams up to 350 GeV/c. \\\\\\\\ a) The directly produced photon yield in deep inelastic hadron-hadron collisions. Large p$_{t}$ direct photons from hadronic interactions are presumably a result of a simple annihilation process of quarks and antiquarks or of a QCD-Compton process. The relative contribution of the two processes can be studied by using various incident beam projectiles $\\pi^{+}, \\pi^{-}, p$ and in the future $\\bar{p}$. \\\\\\\\b) The correlations between directly produced photons and their accompanying hadronic jets. We will examine events with a large p$_{t}$ direct photon for away-side jets. If jets are recognised their properties will be investigated. Differences between a gluon and a quark jet may become observable by comparing reactions where valence quark annihilations (away-side jet originates from a gluon) dominate over the QDC-Compton...
International Nuclear Information System (INIS)
Tarvainen, Tanja; Vauhkonen, Marko; Kolehmainen, Ville; Arridge, Simon R; Kaipio, Jari P
2005-01-01
In this paper, a coupled radiative transfer equation and diffusion approximation model is extended for light propagation in turbid medium with low-scattering and non-scattering regions. The light propagation is modelled with the radiative transfer equation in sub-domains in which the assumptions of the diffusion approximation are not valid. The diffusion approximation is used elsewhere in the domain. The two equations are coupled through their boundary conditions and they are solved simultaneously using the finite element method. The streamline diffusion modification is used to avoid the ray-effect problem in the finite element solution of the radiative transfer equation. The proposed method is tested with simulations. The results of the coupled model are compared with the finite element solutions of the radiative transfer equation and the diffusion approximation and with results of Monte Carlo simulation. The results show that the coupled model can be used to describe photon migration in turbid medium with low-scattering and non-scattering regions more accurately than the conventional diffusion model
Systematic analysis of scaling properties in deep inelastic scattering
International Nuclear Information System (INIS)
Beuf, Guillaume; Peschanski, Robi; Royon, Christophe; Salek, David
2008-01-01
Using the 'quality factor' method, we analyze the scaling properties of deep inelastic processes at the accelerator HERA and fixed target experiments for x≤10 -2 . We look for scaling formulas of the form σ γ * p (τ), where τ(L=logQ 2 ,Y) is a scaling variable suggested by the asymptotic properties of QCD evolution equations with rapidity Y. We consider four cases: 'fixed coupling', corresponding to the original geometric scaling proposal and motivated by the asymptotic properties of the Balitsky-Kovchegov equation with fixed QCD coupling constant; two versions, 'running coupling I, II,' of the scaling suggested by the Balitsky-Kovchegov equation with running coupling; and 'diffusive scaling' suggested by the QCD evolution equation with Pomeron loops. The quality factors, quantifying the phenomenological validity of the candidate scaling variables, are fitted on the total and deeply virtual Compton scattering cross-section data from HERA and predictions are made for the elastic vector meson and for the diffractive cross sections at fixed small x P or β. The first three scaling formulas have comparably good quality factors while the fourth one is disfavored. Adjusting initial conditions gives a significant improvement of the running coupling II scaling.
DEFF Research Database (Denmark)
Kristensen, Philip Trøst; Lodahl, Peter; Mørk, Jesper
2010-01-01
We present an accurate, stable, and efficient solution to the Lippmann–Schwinger equation for electromagnetic scattering in two dimensions. The method is well suited for multiple scattering problems and may be applied to problems with scatterers of arbitrary shape or non-homogenous background mat...
Camargo, Pedro Henrique Cury
In the first part of my dissertation, I developed two approaches for selectively probing the SERS activities of individual hot spots, i.e., experimentally detect the SERS signals only for the molecules that are trapped within the hot-spot region in individual Ag nanoparticle dimers. Then, I performed a systematic investigation on the SERS activity of individual dimers composed of two closed spaced Ag nanoparticles. By utilizing Ag nanoparticles displaying a variety of well-defined shapes, sizes and orientations to construct the dimers, I were able to precisely correlate the detected SERS signals to the specific geometry of individual hot spots. In the second part of this dissertation, I performed a systematic investigation on the galvanic replacement reaction between PtCl62- and Pd nanocrystals with well-defined shapes including octahedra, nanocubes, and nanorods. The resultant hollow Pd-Pt bimetallic nanostructures were employed as electrocatalysts for the oxygen reduction reaction (ORR). Our results demonstrated that the nanostructures derived from Pd octahedra displayed the highest ORR activity, being 1.7 times more active based on equivalent Pt mass than the commercial Pt/C. I also conducted a mechanistic study on the galvanic replacement reaction between AuCl4- and Pd nanorods. Differently from the Pd-Pt system, a new type of hybrid nanostructure in the tadpole shape consisting of a Au head and a Pd tail was obtained due to a localized galvanic replacement mechanism. As an extension of my work to develop new electrocatalysts for the ORR, a templateengaged reaction was utilized for the synthesis of RuSe2+delta nanotubes. The RuSe2+delta nanotubes were active towards the ORR and displayed no loss in activity in the presence of methanol, as opposed to commercial Pt/C. Finally, the template-engaged reaction was applied to the synthesis of Se MSe (M = Zn, Cd or Pb) colloidal spheres having similar sizes but different compositions. They were utilized as building
International Nuclear Information System (INIS)
Fernandez, J.E.; Molinari, V.G.; Sumini, M.
1988-01-01
In the frame of the multiple applications of X-ray techniques a detailed description of the photon transport under several boundary conditions in condensed media is of utmost importance. In this work the photon transport equation for a homogeneous specimen of infinite thickness is considered and an exact iterative solution is reported, which is universally valid for all types of interactions because of its independence of the shape of the interaction kernel. As a test probe we use a specially simple elastic scattering expression that renders possible the exact calculation of the first two orders of the solution. It is shown that the second order does not produce any significant improvement over the first one. Due to its particular characteristics, the first-order solution for the simplified kernel can be extended to include the form factor, thus giving a more realistic description of the coherent scattering of monochromatic radiation by bound electrons. The relevant effects of the scattering anisotropy are also placed in evidence when they are constrated with the isotropic solution calculated in the same way. (author) [pt
International Nuclear Information System (INIS)
Singh, M.P.; Sharma, Amandeep; Singh, Bhajan; Sandhu, B.S.
2010-01-01
The objective of present experiment, employing a scattering of 59.54 keV gamma photons, is to assign effective atomic number (Z eff ) to scientific samples (rare earths) of known composition. An HPGe semiconductor detector, placed at 90 o to the incident beam, detects gamma photons scattered from the sample under investigation. The experiment is performed on various elements with atomic number satisfying, 6≤Z≤82, for 59.54 keV incident photons. The intensity ratio of Rayleigh to Compton scattered peaks, corrected for photo-peak efficiency of gamma detector and absorption of photons in the sample and air, is plotted as a function of atomic number and constituted a best fit-curve. From this fit-curve, the respective effective atomic numbers to samples of rare earths are determined. The agreement of measured values of Z eff with theoretical calculations is quite satisfactory.
Alternative space-time view of vector-meson dominance for virtual-photon--nucleus scattering
International Nuclear Information System (INIS)
Argyres, E.N.; Lam, C.S.
1977-01-01
We clarify the meaning of vector-meson dominance for virtual photons via a coupled-channel formalism, in which the photon can interact only by converting itself into a vector meson, the conversion occurring anywhere in space. We calculate the relative contributions of the different conversion regions, discuss their physical interpretation, and establish the equivalence of this approach to the usual treatment
Coherent control of the single-photon multichannel scattering in the dissipation case
Shi, Yun-Xia; Wang, Hang-Yu; Ma, Jin-Lou; Li, Qing; Tan, Lei
2018-03-01
Based on the quasi-boson approach, a model of a Λ-type three-level atom coupled to a X-shaped coupled cavity arrays (CCAs) is used to study the transport properties of a single-photon in the dissipative case, and a classical field is introduced to motivate the one transition of the Λ-type three-level atom (ΛTLA). The analytical expressions of transmission and transfer rate are obtained. Our results show that the cavity dissipation will obviously weaken the single-photon transfer rate where the incident energy of the single photon is resonant with the excited energy of the atom. Whether the cavity dissipation exists or not, the single photon can be almost confined in the incident channel at large detuning, and we can regulate the intensity of the classical field to control the total transmission of the single-photon.
Post-PRK corneal scatter measurements with a scanning confocal slit photon counter
Taboada, John; Gaines, David; Perez, Mary A.; Waller, Steve G.; Ivan, Douglas J.; Baldwin, J. Bruce; LoRusso, Frank; Tutt, Ronald C.; Perez, Jose; Tredici, Thomas; Johnson, Dan A.
2000-06-01
Increased corneal light scatter or 'haze' has been associated with excimer laser photorefractive surgery of the cornea. The increased scatter can affect visual performance; however, topical steroid treatment post surgery substantially reduces the post PRK scatter. For the treatment and monitoring of the scattering characteristics of the cornea, various methods have been developed to objectively measure the magnitude of the scatter. These methods generally can measure scatter associated with clinically observable levels of haze. For patients with moderate to low PRK corrections receiving steroid treatment, measurement becomes fairly difficult as the haze clinical rating is non observable. The goal of this development was to realize an objective, non-invasive physical measurement that could produce a significant reading for any level including the background present in a normal cornea. As back-scatter is the only readily accessible observable, the instrument is based on this measurement. To achieve this end required the use of a confocal method to bias out the background light that would normally confound conventional methods. A number of subjects with nominal refractive errors in an Air Force study have undergone PRK surgery. A measurable increase in corneal scatter has been observed in these subjects whereas clinical ratings of the haze were noted as level zero. Other favorable aspects of this back-scatter based instrument include an optical capability to perform what is equivalent to an optical A-scan of the anterior chamber. Lens scatter can also be measured.
DEFF Research Database (Denmark)
Iles-Smith, Jake; McCutcheon, Dara; Mørk, Jesper
2016-01-01
a substantial suppression of detrimental interactions between the source and its phonon environment. Nevertheless, we demonstrate here that this reasoning is incomplete, and phonon interactions continue to play a crucial role in determining solid-state emission characteristics even for very weak excitation. We...... find that the sideband resulting from non-Markovian relaxation of the phonon environment leads to a fundamental limit to the fraction of coherently scattered light and to the visibility of two-photon coalescence at weak driving, both of which are absent for atomic systems or within simpler Markovian...
Energy Technology Data Exchange (ETDEWEB)
Appaji Gowda, S.B. [Department of Studies in Physics, Manasagangothri, University of Mysore, Mysore 570006 (India); Umesh, T.K. [Department of Studies in Physics, Manasagangothri, University of Mysore, Mysore 570006 (India)]. E-mail: tku@physics.uni-mysore.ac.in
2006-01-15
Dispersion corrections to the forward Rayleigh scattering amplitudes of tantalum, mercury and lead in the photon energy range 24-136 keV have been determined by a numerical evaluation of the dispersion integral that relates them through optical theorem to the photo effect cross sections. The photo effect cross sections have been extracted by subtracting the coherent and incoherent scattering contribution from the measured total attenuation cross section, using high-resolution high-purity germanium detector in a narrow beam good geometry set up. The real part of the dispersion correction to which the relativistic corrections calculated by Kissel and Pratt (S-matrix approach) or Creagh and McAuley (multipole corrections) have been included are in better agreement with the available theoretical values.
International Nuclear Information System (INIS)
Hubbell, J.H.
1993-01-01
This report reviews available information on polarization effects arising when photons in the X-ray and gamma-ray energy regime undergo coherent (Rayleigh) scattering and incoherent (Compton) scattering by atomic electrons. In addition to descriptions and discussions of these effects, including estimates of their magnitudes as they apply to radiation transport calculations, an annotated bibliography of 102 selected works covering the period 1905-1991 is provided, with particularly relevant works for the purpose of this report flagged with asterisks (*). A major resource for this report is a 1948 unpublished informal report by L.V. Spencer which has been quoted here almost in its entirety, since, of all the works cited in the annotated bibliography, it appears to be the only one which explicitly and directly addresses the purpose of this report. Hence this valuable material should be re-introduced into the available and current literature. (author). 119 refs., 7 figs
International Nuclear Information System (INIS)
Larsson, S.A.; Johansson, L.; Jonsson, C.; Pagani, M.; Jacobsson, H.
2000-01-01
A newly designed technique for experimental single-photon emission tomography (SPET) and positron emission tomography (PET) data acquisition with minor disturbing effects from scatter and attenuation has been developed. In principle, the method is based on discrete sampling of the radioactivity distribution in 3D objects by means of equidistant 2D planes. The starting point is a set of digitised 2D sections representing the radioactivity distribution of the 3D object. Having a radioactivity-related grey scale, the 2D images are printed on paper sheets using radioactive ink. The radioactive sheets can be shaped to the outline of the object and stacked into a 3D structure with air or some arbitrary dense material in between. For this work, equidistantly spaced transverse images of a uniform cylindrical phantom and of the digitised Hoffman rCBF phantom were selected and printed out on paper sheets. The uniform radioactivity sheets were imaged on the surface of a low-energy ultra-high-resolution collimator (4 mm full-width at half-maximum) of a three-headed SPET camera. The reproducibility was 0.7% and the uniformity was 1.2%. Each rCBF sheet, containing between 8.3 and 80 MBq of 99m TcO 4 - depending on size, was first imaged on the collimator and then stacked into a 3D structure with constant 12 mm air spacing between the slices. SPET was performed with the sheets perpendicular to the central axis of the camera. The total weight of the stacked rCBF phantom in air was 63 g, giving a scatter contribution comparable to that of a point source in air. The overall attenuation losses were <20%. A second SPET study was performed with 12-mm polystyrene plates in between the radioactive sheets. With polystyrene plates, the total phantom weight was 2300 g, giving a scatter and attenuation magnitude similar to that of a patient study. With the proposed technique, it is possible to obtain ''ideal'' experimental images (essentially built up by primary photons) for comparison with
DEFF Research Database (Denmark)
Jensen, Jakob Søndergaard; Sigmund, Ole
2004-01-01
Topology optimization is a promising method for systematic design of optical devices. As an example, we demonstrate how the method can be used to design a 90degrees bend in a two-dimensional photonic crystal waveguide with a transmission loss of less than 0.3% in almost the entire frequency range...... of the guided mode. The method can directly be applied to the design of other optical devices, e.g., multiplexers and wave splitters, with optimized performance. (C) 2004 American Institute of Physics....
Qattan, I. A.
2017-05-01
Background: The inconsistency in the results obtained from the Rosenbluth separation method and the high-Q2 recoil polarization results on the ratio μpGEp/GMp implies a systematic difference between the two techniques. Several studies suggest that missing higher-order radiative corrections to elastic electron-proton scattering cross section σR(ɛ ,Q2) and in particular hard two-photon-exchange (TPE) contributions could account for the discrepancy. Purpose: In this work, I improve on and extend to low and high Q2 values the extractions of the ɛ dependence of the real parts of the TPE amplitudes relative to the magnetic form factor, as well as the ratio Pl/PlBorn(ɛ ,Q2) by using world data on σR(ɛ ,Q2) with an emphasis on precise new data covering the low-momentum region which is sensitive to the large-scale structure of the nucleon. Method: I combine cross section and polarization measurements of elastic electron-proton scattering to extract the TPE amplitudes. Because the recoil polarization data were confirmed "experimentally" to be essentially independent of ɛ , I constrain the ratio Pt/Pl(ɛ ,Q2) to its ɛ -independent term (Born value) by setting the TPE contributions to zero. This allows for the amplitude YM(ɛ ,Q2) and σR(ɛ ,Q2) to be expressed in terms of the remaining two amplitudes YE(ɛ ,Q2) and Y3(ɛ ,Q2) which in turn are parametrized as second-order polynomials in ɛ and Q2 to reserve as possible the linearity of σR(ɛ ,Q2) as well as to account for possible nonlinearities in the TPE amplitudes. Furthermore, I impose the Regge limit which ensures the vanishing of the TPE contributions to σR(ɛ ,Q2) and the TPE amplitudes in the limit ɛ →1 . Results: I provide simple parametrizations of the TPE amplitudes, along with an estimate of the fit uncertainties. The extracted TPE amplitudes are compared with previous phenomenological extractions and TPE calculations. The Pl/PlBorn ratio is extracted by using the new parametrizations of the TPE
International Nuclear Information System (INIS)
Burke, D.L.
1982-10-01
Studies of photon-photon collisions are reviewed with particular emphasis on new results reported to this conference. These include results on light meson spectroscopy and deep inelastic e#betta# scattering. Considerable work has now been accumulated on resonance production by #betta##betta# collisions. Preliminary high statistics studies of the photon structure function F 2 /sup #betta#/(x,Q 2 ) are given and comments are made on the problems that remain to be solved
International Nuclear Information System (INIS)
Haissinski, J.
1986-06-01
The discussions presented in this paper deal with the following points: distinctive features of gamma-gamma collisions; related processes; photon-photon elastic scattering in the continuum and γγ →gg; total cross section; γγ → V 1 V 2 (V=vector meson); radiative width measurements and light meson spectroscopy; exclusive channels at large /t/; jets and inclusive particle distribution in γγ collisions; and, the photon structure function F γ 2
Ivanov, K. A.; Nikolaev, V. V.; Gubaydullin, A. R.; Kaliteevski, M. A.
2017-10-01
Based on the scattering matrix formalism, we have developed a method of quantization of an electromagnetic field in two-dimensional photonic nanostructures ( S-quantization in the two-dimensional case). In this method, the fields at the boundaries of the quantization box are expanded into a Fourier series and are related with each other by the scattering matrix of the system, which is the product of matrices describing the propagation of plane waves in empty regions of the quantization box and the scattering matrix of the photonic structure (or an arbitrary inhomogeneity). The quantization condition (similarly to the onedimensional case) is formulated as follows: the eigenvalues of the scattering matrix are equal to unity, which corresponds to the fact that the set of waves that are incident on the structure (components of the expansion into the Fourier series) is equal to the set of waves that travel away from the structure (outgoing waves). The coefficients of the matrix of scattering through the inhomogeneous structure have been calculated using the following procedure: the structure is divided into parallel layers such that the permittivity in each layer varies only along the axis that is perpendicular to the layers. Using the Fourier transform, the Maxwell equations have been written in the form of a matrix that relates the Fourier components of the electric field at the boundaries of neighboring layers. The product of these matrices is the transfer matrix in the basis of the Fourier components of the electric field. Represented in a block form, it is composed by matrices that contain the reflection and transmission coefficients for the Fourier components of the field, which, in turn, constitute the scattering matrix. The developed method considerably simplifies the calculation scheme for the analysis of the behavior of the electromagnetic field in structures with a two-dimensional inhomogeneity. In addition, this method makes it possible to obviate
International Nuclear Information System (INIS)
Hillenbrand, Rainer
2004-01-01
Diffraction limits the spatial resolution in classical microscopy or the dimensions of optical circuits to about half the illumination wavelength. Scanning near-field microscopy can overcome this limitation by exploiting the evanescent near fields existing close to any illuminated object. We use a scattering-type near-field optical microscope (s-SNOM) that uses the illuminated metal tip of an atomic force microscope (AFM) to act as scattering near-field probe. The presented images are direct evidence that the s-SNOM enables optical imaging at a spatial resolution on a 10 nm scale, independent of the wavelength used (λ=633 nm and 10 μm). Operating the microscope at specific mid-infrared frequencies we found a tip-induced phonon-polariton resonance on flat polar crystals such as SiC and Si 3 N 4 . Being a spectral fingerprint of any polar material such phonon-enhanced near-field interaction has enormous applicability in nondestructive, material-specific infrared microscopy at nanoscale resolution. The potential of s-SNOM to study eigenfields of surface polaritons in nanostructures opens the door to the development of phonon photonics--a proposed infrared nanotechnology that uses localized or propagating surface phonon polaritons for probing, manipulating and guiding infrared light in nanoscale devices, analogous to plasmon photonics
International Nuclear Information System (INIS)
Hreus, Tomas
2008-09-01
In this thesis, two studies of the diffractive phenomena in the electron proton collisions with the H1 detector at HERA are presented. The rst is the study of the inclusive elastic diffractive events ep → eXp in the regime of high photon virtuality (Q 2 >few GeV 2 ), with the scattered proton detected by the Very Forward Proton Spectrometer (VFPS). The VFPS detector, designed to measure diffractive scattered protons with high acceptance, has been installed in 2004 to benefit from the HERA II luminosity increase. The selected event sample of an integrated luminosity of 130.2 pb -1 was collected in years 2006-2007. Data sample distributions are compared to the prediction based on the diffractive parton distribution functions, as extracted from the H1 measurement of the diffractive structure function F D(3) 2 at HERA I. After the study of the VFPS efficiency, the VFPS acceptance as a function of x P is estimated and studied in relation to the forward proton beam optics. The second study leads to the cross section measurement of the diffractive scattering of quasi-real photons off protons, γp → γY, with the large momentum transfer, vertical stroke t vertical stroke. The final state photon is separated from the proton dissociation system, Y, by a large rapidity gap and has a large transverse momentum, p T > 2 GeV. Large p T imply the presence of the hard scale t (vertical stroke t vertical stroke ≅ p 2 T ) and allows predictions of the perturbative QCD to be applied. The measurement is based on an integrated luminosity 46.2 pb -1 of data collected in the 1999-2000 running period. Cross sections σ(W) as a function of the incident photon-proton centre of mass energy, W, and dσ/d vertical stroke t vertical stroke are measured in the range Q 2 2 , 175 2 and y P <0.05. The cross section measurements have been compared to predictions of LLA BFKL calculations. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Hreus, Tomas
2008-11-15
In this thesis, two studies of the diffractive phenomena in the electron proton collisions with the H1 detector at HERA are presented. The rst is the study of the inclusive elastic diffractive events ep {yields} eXp in the regime of high photon virtuality (Q{sup 2}>few GeV{sup 2}), with the scattered proton detected by the Very Forward Proton Spectrometer (VFPS). The VFPS detector, designed to measure diffractive scattered protons with high acceptance, has been installed in 2004 to benefit from the HERA II luminosity increase. The selected event sample of an integrated luminosity of 130.2 pb{sup -1} was collected in years 2006-2007. Data sample distributions are compared to the prediction based on the diffractive parton distribution functions, as extracted from the H1 measurement of the diffractive structure function F{sup D(3)}{sub 2} at HERA I. After the study of the VFPS efficiency, the VFPS acceptance as a function of x{sub P} is estimated and studied in relation to the forward proton beam optics. The second study leads to the cross section measurement of the diffractive scattering of quasi-real photons off protons, {gamma}p {yields} {gamma}Y, with the large momentum transfer, vertical stroke t vertical stroke. The final state photon is separated from the proton dissociation system, Y, by a large rapidity gap and has a large transverse momentum, p{sub T} > 2 GeV. Large p{sub T} imply the presence of the hard scale t (vertical stroke t vertical stroke {approx_equal} p{sup 2}{sub T}) and allows predictions of the perturbative QCD to be applied. The measurement is based on an integrated luminosity 46.2 pb{sup -1} of data collected in the 1999-2000 running period. Cross sections {sigma}(W) as a function of the incident photon-proton centre of mass energy, W, and d{sigma}/d vertical stroke t vertical stroke are measured in the range Q{sup 2}<0.01 GeV{sup 2}, 175
Measurement of recoil photon polarisation in the electron-proton elastic scattering
International Nuclear Information System (INIS)
Buon, Jean
1965-02-01
This research thesis reports and discusses an experiment which aimed at checking the validity of the Born approximation at the first order in the elastic scattering of high energy electrons on protons. In this experiment, the recoil proton polarisation is measured in an elastic scattering of electrons with energy of 950 MeV and scattering at about 90 degrees in the mass centre system. The author describes the experimental installation, its operation and data collection, reports the analysis of photos and polarisation calculations and errors [fr
Design of an arrangement for the production of a scattered photon field and the flux measurement
International Nuclear Information System (INIS)
Legarda, F.; Herranz, M.
1992-01-01
The design of an arrangement to create and measure a scattered radiation field is described. The expected flux distribution has been calculated using Monte Carlo techniques (EGS4 system). The proposed measurement system includes a collimator with an opening of 0.2deg and a detector with a ∝2% energy resolution. This system should have a positional uncertainty of millimetre, and a small amount (0.6%) of radiation scattered back from the measurement system to the source. (orig.)
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.
Jet and hadron production in photon-photon collisions
Soldner-Rembold, Stefan
1999-01-01
Di-jet and inclusive charged hadron production cross-sections measured in photon-photon collisions by OPAL are compared to NLO pQCD calculations. Jet shapes measured in photon-photon scattering by OPAL, in deep-inelastic ep scattering by H1 and in photon-proton scattering by ZEUS are shown to be consistent in similar kinematic ranges. New results from TOPAZ on prompt photon production in photon-photon interactions are presented.
Xu, Xiaofei; Xing, Yuxiang; Wang, Sen; Zhang, Li
2018-06-01
X-ray liquid security inspection system plays an important role in homeland security, while the conventional dual-energy CT (DECT) system may have a big deviation in extracting the atomic number and the electron density of materials in various conditions. Photon counting detectors (PCDs) have the capability of discriminating the incident photons of different energy. The technique becomes more and more mature in nowadays. In this work, we explore the performance of a multi-energy CT imaging system with a PCD for liquid security inspection in material discrimination. We used a maximum-likelihood (ML) decomposition method with scatter correction based on a cross-energy response model (CERM) for PCDs so that to improve the accuracy of atomic number and electronic density imaging. Experimental study was carried to examine the effectiveness and robustness of the proposed system. Our results show that the concentration of different solutions in physical phantoms can be reconstructed accurately, which could improve the material identification compared to current available dual-energy liquid security inspection systems. The CERM-base decomposition and reconstruction method can be easily used to different applications such as medical diagnosis.
Near-field imaging of out-of-plane light scattering in photonic crystal slabs
DEFF Research Database (Denmark)
Volkov, Valentyn; Bozhevolnyi, Sergey; Taillaert, Dirk
2003-01-01
A collection scanning near-field optical microscope (SNOM) is used to image the propagating of light at telecommunication wavelengths (1520-1570 nm) along photonic crystal (PC) slabs, which combine slab waveguides with in-plane PCs consisting of one- and two-dimensional gratings. The efficient out...
Time-resolved X-ray scattering program at the Advanced Photon Source
International Nuclear Information System (INIS)
Rodricks, B.
1994-01-01
The Time-Resolved Scattering Program's goal is the development of instruments and techniques for time-resolved studies. This entails the development of wide bandpass and focusing optics, high-speed detectors, mechanical choppers, and components for the measurement and creation of changes in samples. Techniques being developed are pump-probe experiments, single-bunch scattering experiments, high-speed white and pink beam Laue scattering, and nanosecond to microsecond synchronization of instruments. This program will be carried out primarily from a white-beam, bend-magnet source, experimental station, 1-BM-B, that immediately follows the first optics enclosure (1-BM-A). This paper will describe the experimental station and instruments under development to carry out the program
Characterization of Scattered X-Ray Photons in Dental Cone-Beam Computed Tomography.
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.
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.
Compton scattering of 145 keV photons from bound electrons of tin and molybdenum
Energy Technology Data Exchange (ETDEWEB)
Ghumman, B S; Acharya, V B; Singh, B [Punjabi Univ., Patiala (India). Dept. of Physics
1981-10-28
Differential cross sections for Compton scattering of 145 keV gamma rays from K-shell electrons of tin and molybdenum are measured at scattering angles in the range 30 to 150/sup 0/. Measurements are made employing NaI(Tl) detectors and a coincidence set up with resolving time approximately equal to 30 ns. The experimental results are compared with the available theoretical data. The total cross section is estimated to be about 0.43 sigmasub(F) for tin and 0.41 sigmasub(F) for molybdenum.
International Nuclear Information System (INIS)
Jung, M.; Kattein, J.; Kueck, H.; Leu, P.; Marne, K.D. de; Wedemeyer, R.; Wermes, N.
1981-05-01
Differential cross sections of proton Compton scattering have been measured at the Bonn 2.5 GeV synchrotron. 78 data points are presented as angular distributions at photon lab energies of 700, 750, 800, 850, 900, and 950 MeV. The c.m. scattering angle ranges from 40 0 to 130 0 , corresponding to a variation of the four momentum transfer squared between t = -0.10 to t = -0.96 GeV 2 at 700 and 950 MeV, respectively. Two additional differential cross sections have been measured at 1000 MeV, 35.6 0 and 47.4 0 . The angular distributions show forward peaks whose extrapolations to 0 0 are consistent with calculated forward cross sections taken from literature. The small angle data ( vertical stroke t vertical stroke approx. 2 ) together with the calculated cross sections at 0 0 are also consistent with the assumption of a slope parameter B of 5 GeV -2 . For the first time a re-rise of the angular distributions towards backward angles has been observed. It becomes less steep with increasing energy. The most interesting feature of the angular distributions is a sharp structure which appears between t = -0.55 GeV 2 at 700 MeV and t = -0.72 GeV 2 at 950 MeV. Such a rapid variation of the differential cross section with t has never been observed in elastic hadron-hadron scattering or photoproduction processes. It indicates the existence of a dynamical mechanism which could be a peculiarity of Compton scattering. (orig.)
International Nuclear Information System (INIS)
Kamphuis, C.; Beekman, F.J.; Van Rijk, P.P.; Viergever, M.A.
1998-01-01
Three-dimensional (3D) iterative maximum likelihood expectation maximization (ML-EM) algorithms for single-photon emission tomography (SPET) are capable of correcting image-degrading effects of non-uniform attenuation, distance-dependent camera response and patient shape-dependent scatter. However, the resulting improvements in quantitation, resolution and signal-to-noise ratio (SNR) are obtained at the cost of a huge computational burden. This paper presents a new acceleration method for ML-EM: dual matrix ordered subsets (DM-OS). DM-OS combines two acceleration methods: (a) different matrices for projection and back-projection and (b) ordered subsets of projections. DM-OS was compared with ML-EM on simulated data and on physical thorax phantom data, for both 180 and 360 orbits. Contrast, normalized standard deviation and mean squared error were calculated for the digital phantom experiment. DM-OS resulted in similar image quality to ML-EM, even for speed-up factors of 200 compared to ML-EM in the case of 120 projections. The thorax phantom data could be reconstructed 50 times faster (60 projections) using DM-OS with preservation of image quality. ML-EM and DM-OS with scatter compensation showed significant improvement of SNR compared to ML-EM without scatter compensation. Furthermore, inclusion of complex image formation models in the computer code is simplified in the case of DM-OS. It is thus shown that DM-OS is a fast and relatively simple algorithm for 3D iterative scatter compensation, with similar results to conventional ML-EM, for both 180 and 360 acquired data. (orig.)
International Nuclear Information System (INIS)
Datta, Gulshan; Saddi, M.B.; Singh, B.; Sandhu, B.S.
2007-01-01
The doubly differential collision cross-sections of the double-photon Compton process have been measured experimentally for 0.662 MeV incident gamma photons. The measurements are carried out using a single gamma detector, a technique avoiding the use of the complicated slow-fast coincidence set-up used till now for observing this higher order QED process. The energy spectra of detected photons are observed as a long tail to the single-photon Compton line on the lower side of the full energy peak in the recorded scattered energy spectrum. The measured values of the cross-section for different independent energy levels of one of the two final photons are of the same magnitude but show deviation from the corresponding values obtained from the theory. However, the present measurements are first of its kind and in view of the nature and order of deviations, the agreement of measured values with theory is quite satisfactory
Systematic analysis of α elastic scattering with the São Paulo potential
Energy Technology Data Exchange (ETDEWEB)
Charry-Pastrana, F. E., E-mail: feecharrypa@unal.edu.co; Pinilla, E. C. [Universidad Nacional de Colombia, Sede Bogotá, Facultad de Ciencias, Departamento de Física, Grupo de Física Nuclear, Carrera 45 No. 26-85, Edificio Uriel Gutiérrez, Bogotá D.C., Código Postal 111321 (Colombia)
2016-07-07
We describe systematically by collision energy and target mass, alpha elastic scattering angular distributions by using the São Paulo potential as the real part of the optical potential. The imaginary part is proportional to the real one by a factor N{sub i}. We find this parameter by fitting the theoretical angular distributions to the experimental cross sections through a χ{sup 2} minimization. The N{sub i} and their respective uncertainties, σ{sub Ni}, fall in the range 0.4 ≤ N{sub i} ± σ{sub N{sub i}} ≤ 0.8 for all the systems studied.
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)
International Nuclear Information System (INIS)
Harriman, P.N.; Martin, A.D.; Stirling, W.J.; Roberts, R.G.
1990-01-01
We present a next-to-leading-order QCD structure function analysis of deep-inelastic muon and neutrino scattering data. In particular, we incorporate new F 2 μn /F 2 μp data and take account of a recent re-analysis of SLAC data. The fit is performed simultaneously with next-to-leading-order fits to recent prompt photon and Drell-Yan data. As a result we are able to place tighter constraints on the quark and gluon distributions. Two definitive sets of parton distributions are presented according to which set of muon data is included in the global fit. Comparisons with distributions obtained in earlier analyses are made and the consistency of data sets is investigated. (author)
Georgakopoulos, A.; Politopoulos, K.; Georgiou, E.
2018-03-01
A new dynamic-system approach to the problem of radiative transfer inside scattering and absorbing media is presented, directly based on first-hand physical principles. This method, the Dynamic Radiative Transfer System (DRTS), employs a dynamical system formality using a global sparse matrix, which characterizes the physical, optical and geometrical properties of the material-volume of interest. The new system state is generated by the above time-independent matrix, using simple matrix-vector multiplication for each subsequent time step. DRTS is capable of calculating accurately the time evolution of photon propagation in media of complex structure and shape. The flexibility of DRTS allows the integration of time-dependent sources, boundary conditions, different media and several optical phenomena like reflection and refraction in a unified and consistent way. Various examples of DRTS simulation results are presented for ultra-fast light pulse 3-D propagation, demonstrating greatly reduced computational cost and resource requirements compared to other methods.
Energy Technology Data Exchange (ETDEWEB)
Kuramochi, Eiichi, E-mail: kuramochi.eiichi@lab.ntt.co.jp; Nozaki, Kengo; Shinya, Akihiko; Taniyama, Hideaki; Notomi, Masaya [NTT Nanophotonics Center, NTT Corporation, 3-1 Morinosato Wakamiya, Atsugi, Kanagawa 243-0198 (Japan); NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato Wakamiya, Atsugi, Kanagawa 243-0198 (Japan); Takeda, Koji; Matsuo, Shinji [NTT Nanophotonics Center, NTT Corporation, 3-1 Morinosato Wakamiya, Atsugi, Kanagawa 243-0198 (Japan); NTT Device Technology Laboratories, NTT Corporation, 3-1 Morinosato Wakamiya, Atsugi, Kanagawa 243-0198 (Japan); Sato, Tomonari [NTT Nanophotonics Center, NTT Corporation, 3-1 Morinosato Wakamiya, Atsugi, Kanagawa 243-0198 (Japan)
2015-11-30
An InP photonic crystal nanocavity with an embedded InGaAsP active region is a unique technology that has realized an all-optical memory with a sub-micro-watt operating power and limitless storage time. In this study, we employed an L3 design with systematic multi-hole tuning, which realized a higher loaded Q factor (>40 000) and a lower mode volume (0.9 μm{sup 3}) than a line-defect-based buried-heterostructure nanocavity (16 000 and 2.2 μm{sup 3}). Excluding the active region realized a record loaded Q factor (210 000) in all for InP-based nanocavities. The minimum bias power for bistable memory operation was reduced to 2.3 ± 0.3 nW, which is about 1/10 of the previous record of 30 nW. This work further established the capability of a bistable nanocavity memory for use in future ultralow-power-consumption on-chip integrated photonics.
International Nuclear Information System (INIS)
Guiasu, I.
1978-01-01
The elastic γ-nucleon scattering represents an indirect powerful method for the nucleon structure investigation. Some theoretical aspects of this problem are treated in the presented thesis. After a general introduction into the subject and a short review of the up-to-date literature, the first chapter contains kinematics and dynamical preliminaries of reaction γ+N→γ+N. In chapter II, the low energy theorems are discussed and extended up to six power in the photon laboratory energies, ω; the six structure dependent constants which appear in the differential cross section in this order are defined and computed, and an extraction for the proton electromagnetic polarizabilities α,β from the experimental data is performed. A new dispersive analysis of the γ+N→γ+N process at photon laboratory energies lower than 450 Mev is introduced and used for numerical calculation in chapter III; some improvements are obtained in the comparison with the experimental data, with respect to other previous calculations. In the last chapter, two different sum rules for the difference (α-β) are established and numerically computed - these theoretical predictions agree with the values extracted from experience; based on the analyticity properties of the invariant amplitudes, an inequality is written down connecting an integral over the differential cross section of the process and the static properties of the nucleon (mass, charge, anomalous magnetic moment). (author)
Semenova, L. E.
2018-04-01
The hyper-Raman scattering of light by LO-phonons under two-photon excitation near resonance with the An=2 exciton level in the wurtzite semiconductors A2B6 was theoretically investigated, taking into account the influence of the complex structure of the top valence band.
Energy Technology Data Exchange (ETDEWEB)
Verma, S L; Allawadhi, K L; Sood, B S [Punjabi Univ., Patiala (India). Dept. of Physics
1978-04-01
Integral K-shell Compton scattering cross-sections in elements Nb, Mo, Ag, Cd, In, Sn and Sb have been determined for 1250 keV photons. The results when compared with theory suggest that K-shell electrons in the elements under investigation behave as free electrons.
Detection of forward-scattered protons in photon-induced reactions on the nucleon
International Nuclear Information System (INIS)
Koop, Karsten
2015-01-01
The study of excitation spectra of hadrons can contribute to a better understanding of the strong interaction. A method is the photoproduction of mesons on the nucleon. Because of the width of the excited states a consideration of polarization observables is helpful in order to be abble to separate overlapping states. In this thesis an experiment for the study of the polarization of the recoil proton is presented. The setup presented here is part of the BGO-OD experiment at the ELSA electron accelerator of the Bonn university. BGO-OD consists of an electromagnetic calorimeter, which surrounds the target, several track detectors in forward direction, and a dipole magnet for the momentum measurement of charged particles. The presented detector is located immediately behind the liquid hydrogen target. In order to be able to determine the polarization of the recoil proton these are scattered on an analyzer, whereby the distribution of the scattering angles is polarization dependent. In this thesis a detector was developed in order to determine the track of the charged particles before and behind the target and by this the scattering angle. Furthermore simulations were performed, which show the realizability of the experiment.
Geant4 simulations on Compton scattering of laser photons on relativistic electrons
Energy Technology Data Exchange (ETDEWEB)
Filipescu, D. [Extreme Light Infrastructure - Nuclear Physics, str. Atomistilor nr. 407, Bucharest-Magurele, P.O.BOX MG6, Romania and National Institute for Physics and Nuclear Engineering Horia Hulubei, str. Atomistilor nr. 407 (Romania); Utsunomiya, H. [Department of Physics, Konan University, Okamoto 8-9-1, Higashinada, Kobe 658-8501 (Japan); Gheorghe, I.; Glodariu, T. [National Institute for Physics and Nuclear Engineering Horia Hulubei, str. Atomistilor nr. 407 (Romania); Tesileanu, O. [Extreme Light Infrastructure - Nuclear Physics, str. Atomistilor nr. 407, Bucharest-Magurele, P.O.BOX MG6 (Romania); Shima, T.; Takahisa, K. [Research Center for Nuclear Physics, Osaka University, Suita, Osaka 567-0047 (Japan); Miyamoto, S. [Laboratory of Advanced Science and Technology for Industry, University of Hyogo, 3-1-2 Kouto, Kamigori, Hyogo 678-1205 (Japan)
2015-02-24
Using Geant4, a complex simulation code of the interaction between laser photons and relativistic electrons was developed. We implemented physically constrained electron beam emittance and spacial distribution parameters and we also considered a Gaussian laser beam. The code was tested against experimental data produced at the γ-ray beam line GACKO (Gamma Collaboration Hutch of Konan University) of the synchrotron radiation facility NewSUBARU. Here we will discuss the implications of transverse missallignments of the collimation system relative to the electron beam axis.
Henderson, B. S.; Ice, L. D.; Khaneft, D.; O'Connor, C.; Russell, R.; Schmidt, A.; Bernauer, J. C.; Kohl, M.; Akopov, N.; Alarcon, R.; Ates, O.; Avetisyan, A.; Beck, R.; Belostotski, S.; Bessuille, J.
2016-01-01
The OLYMPUS Collaboration reports on a precision measurement of the positron-proton to electron-proton elastic cross section ratio, \\ud R\\ud 2\\ud γ\\ud , a direct measure of the contribution of hard two-photon exchange to the elastic cross section. In the OLYMPUS measurement, 2.01 GeV electron and positron beams were directed through a hydrogen gas target internal to the DORIS storage ring at DESY. A toroidal magnetic spectrometer instrumented with drift chambers and time-of-flight scintillato...
Henderson, Brian; Ice, Lauren; Ates, Ozgur; Avetisyan, Albert; Beck, Reinhard; Belostotski, Stanislav; Bessuille, Jason; Brinker, Frank; Calarco, John; Carassiti, V.; Cisbani, E.; Ciullo, G.; Khaneft, Dmitry; Contalbrigo, Marco; De Leo, R.
2017-01-01
The OLYMPUS collaboration reports on a precision measurement of the positron-proton to electron-proton elastic cross section ratio, $\\it R_{2 \\gamma}$, a direct measure of the contribution of hard two-photon exchange to the elastic cross section. In the OLYMPUS measurement, 2.01 GeV electron and positron beams were directed through a hydrogen gas target internal to the DORIS storage ring at DESY. A toroidal magnetic spectrometer instrumented with drift chambers and time-of-flight scintillator...
International Nuclear Information System (INIS)
Andreev, V.; Baghdasaryan, A.; Begzsuren, K.
2014-03-01
Measurements of normalised cross sections for the production of photons and neutrons at very small angles with respect to the proton beam direction in deep-inelastic ep scattering at HERA are presented as a function of the Feynman variable x F and of the centre-of-mass energy of the virtual photon-proton system W. The data are taken with the H1 detector in the years 2006 and 2007 and correspond to an integrated luminosity of 131 pb -1 . The measurement is restricted to photons and neutrons in the pseudorapidity range η > 7.9 and covers the range of negative four momentum transfer squared at the positron vertex 6 2 2 , of inelasticity 0.05 F dependent cross sections is investigated. Predictions of deep-inelastic scattering models and of models for hadronic interactions of high energy cosmic rays are compared to the measured cross sections.
Mann, Nishan; Hughes, Stephen
2018-02-01
We present the analytical and numerical details behind our recently published article [Phys. Rev. Lett. 118, 253901 (2017), 10.1103/PhysRevLett.118.253901], describing the impact of disorder-induced multiple scattering on counterpropagating solitons in photonic crystal waveguides. Unlike current nonlinear approaches using the coupled mode formalism, we account for the effects of intraunit cell multiple scattering. To solve the resulting system of coupled semilinear partial differential equations, we introduce a modified Crank-Nicolson-type norm-preserving implicit finite difference scheme inspired by the transfer matrix method. We provide estimates of the numerical dispersion characteristics of our scheme so that optimal step sizes can be chosen to either minimize numerical dispersion or to mimic the exact dispersion. We then show numerical results of a fundamental soliton propagating in the presence of multiple scattering to demonstrate that choosing a subunit cell spatial step size is critical in accurately capturing the effects of multiple scattering, and illustrate the stochastic nature of disorder by simulating soliton propagation in various instances of disordered photonic crystal waveguides. Our approach is easily extended to include a wide range of optical nonlinearities and is applicable to various photonic nanostructures where power propagation is bidirectional, either by choice, or as a result of multiple scattering.
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.
Measurement of the Hadronic Cross-Section for the Scattering of Two Virtual Photons at LEP
Abbiendi, G.; Akesson, P.F.; Alexander, G.; Allison, John; Anagnostou, G.; Anderson, K.J.; Arcelli, S.; Asai, S.; Axen, D.; Azuelos, G.; Bailey, I.; Barberio, E.; Barlow, R.J.; Batley, R.J.; Behnke, T.; Bell, Kenneth Watson; Bell, P.J.; Bella, G.; Bellerive, A.; Bethke, S.; Biebel, O.; Bloodworth, I.J.; Boeriu, O.; Bock, P.; Bohme, J.; Bonacorsi, D.; Boutemeur, M.; Braibant, S.; Brigliadori, L.; Brown, Robert M.; Burckhart, H.J.; Cammin, J.; Carnegie, R.K.; Caron, B.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, David G.; Clarke, P.E.L.; Clay, E.; Cohen, I.; Couchman, J.; Csilling, A.; Cuffiani, M.; Dado, S.; Dallavalle, G.Marco; Dallison, S.; De Roeck, A.; De Wolf, E.A.; Dervan, P.; Desch, K.; Dienes, B.; Dixit, M.S.; Donkers, M.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Etzion, E.; Fabbri, F.; Feld, L.; Ferrari, P.; Fiedler, F.; Fleck, I.; Ford, M.; Frey, A.; Furtjes, A.; Futyan, D.I.; Gagnon, P.; Gary, J.W.; Gaycken, G.; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Glenzinski, D.; Goldberg, J.; Graham, K.; Gross, E.; Grunhaus, J.; Gruwe, M.; Gunther, P.O.; Gupta, A.; Hajdu, C.; Hamann, M.; Hanson, G.G.; Harder, K.; Harel, A.; Harin-Dirac, M.; Hauschild, M.; Hauschildt, J.; Hawkes, C.M.; Hawkings, R.; Hemingway, R.J.; Hensel, C.; Herten, G.; Heuer, R.D.; Hill, J.C.; Hoffman, Kara Dion; Homer, R.J.; Horvath, D.; Hossain, K.R.; Howard, R.; Huntemeyer, P.; Igo-Kemenes, P.; Ishii, K.; Jawahery, A.; Jeremie, H.; Jones, C.R.; Jovanovic, P.; Junk, T.R.; Kanaya, N.; Kanzaki, J.; Karapetian, G.; Karlen, D.; Kartvelishvili, V.; Kawagoe, K.; Kawamoto, T.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Kim, D.H.; Klein, K.; Klier, A.; Kluth, S.; Kobayashi, T.; Kobel, M.; Kokott, T.P.; Komamiya, S.; Kowalewski, Robert V.; Kramer, T.; Kress, T.; Krieger, P.; von Krogh, J.; Krop, D.; Kuhl, T.; Kupper, M.; Kyberd, P.; Lafferty, G.D.; Landsman, H.; Lanske, D.; Lawson, I.; Layter, J.G.; Leins, A.; Lellouch, D.; Letts, J.; Levinson, L.; Lillich, J.; Littlewood, C.; Lloyd, S.L.; Loebinger, F.K.; Long, G.D.; Losty, M.J.; Lu, J.; Ludwig, J.; Macchiolo, A.; Macpherson, A.; Mader, W.; Marcellini, S.; Marchant, T.E.; Martin, A.J.; Martin, J.P.; Martinez, G.; Masetti, G.; Mashimo, T.; Mattig, Peter; McDonald, W.John; McKenna, J.; McMahon, T.J.; McPherson, R.A.; Meijers, F.; Mendez-Lorenzo, P.; Menges, W.; Merritt, F.S.; Mes, H.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Moed, S.; Mohr, W.; Mori, T.; Mutter, A.; Nagai, K.; Nakamura, I.; Neal, H.A.; Nisius, R.; O'Neale, S.W.; Oh, A.; Okpara, A.; Oreglia, M.J.; Orito, S.; Pahl, C.; Pasztor, G.; Pater, J.R.; Patrick, G.N.; Pilcher, J.E.; Pinfold, J.; Plane, David E.; Poli, B.; Polok, J.; Pooth, O.; Przybycien, M.; Quadt, A.; Rabbertz, K.; Rembser, C.; Renkel, P.; Rick, H.; Rodning, N.; Roney, J.M.; Rosati, S.; Roscoe, K.; Rozen, Y.; Runge, K.; Rust, D.R.; Sachs, K.; Saeki, T.; Sahr, O.; Sarkisyan, E.K.G.; Sbarra, C.; Schaile, A.D.; Schaile, O.; Scharff-Hansen, P.; Schroder, Matthias; Schumacher, M.; Schwick, C.; Scott, W.G.; Seuster, R.; Shears, T.G.; Shen, B.C.; Shepherd-Themistocleous, C.H.; Sherwood, P.; Skuja, A.; Smith, A.M.; Snow, G.A.; Sobie, R.; Soldner-Rembold, S.; Spagnolo, S.; Spano, F.; Sproston, M.; Stahl, A.; Stephens, K.; Strom, David M.; Strohmer, R.; Stumpf, L.; Surrow, B.; Tarem, S.; Tasevsky, M.; Taylor, R.J.; Teuscher, R.; Thomas, J.; Thomson, M.A.; Torrence, E.; Toya, D.; Trefzger, T.; Tricoli, A.; Trigger, I.; Trocsanyi, Z.; Tsur, E.; Turner-Watson, M.F.; Ueda, I.; Ujvari, B.; Vachon, B.; Vollmer, C.F.; Vannerem, P.; Verzocchi, M.; Voss, H.; Vossebeld, J.; Waller, D.; Ward, C.P.; Ward, D.R.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wengler, T.; Wermes, N.; Wetterling, D.; Wilson, G.W.; Wilson, J.A.; Wyatt, T.R.; Yamashita, S.; Zacek, V.; Zer-Zion, D.
2001-01-01
The interaction of virtual photons is investigated using the reaction e+e- -> e+e- hadrons based on data taken by the OPAL experiment at e+e- centre-of-mass energies sqrt(s_ee)=189-209 GeV, for W>5 GeV and at an average Q^2 of 17.9 GeV^2. The measured cross-sections are compared to predictions of the Quark Parton Model (QPM), to the Leading Order QCD Monte Carlo model PHOJET to the NLO prediction for the reaction e+e- -> e+e-qqbar, and to BFKL calculations. PHOJET, NLO e+e- -> e+e-qqbar, and QPM describe the data reasonably well, whereas the cross-section predicted by a Leading Order BFKL calculation is too large.
Quantum Darwinism in an Everyday Environment: Huge Redundancy in Scattered Photons
Riedel, Charles; Zurek, Wojciech
2011-03-01
We study quantum Darwinism---the redundant recording of information about the preferred states of a decohering system by its environment---for an object illuminated by a blackbody. In the cases of point-source, small disk, and isotropic illumination, we calculate the quantum mutual information between the object and its photon environment. We demonstrate that this realistic model exhibits fast and extensive proliferation of information about the object into the environment and results in redundancies orders of magnitude larger than the exactly soluble models considered to date. We also demonstrate a reduced ability to create records as initial environmental mixedness increases, in agreement with previous studies. This research is supported by the U.S. Department of Energy through the LANL/LDRD program and, in part, by the Foundational Questions Institute (FQXi).
International Nuclear Information System (INIS)
Guiasu, I.
1978-01-01
The goals of this work are: a) to examine and turn to account in the study of γ-proton elastic scattering the possibility of using a dispersion representation assumed for the amplitude set Asub(i), free of singularities and kinematic zeroes. This is achieved through a direct calculation of the effective unpolarized differential section of the Compton effect on the proton, at various scattering angles in an energy range of 0 β which agrees with current experimental data. c) to establish a law regarding low ω 5 order energies for the helicity amplitudes and for the unpolarized differential effective section of the process γ + p → γ' + p'. We believe this law to be necessary on one hand for a more accurate determination of the α, β variables out of existent experiments and, on the other hand, for the opportunity to define within the Compton effect on the nucleon new structure constants of the nucleon such as the quadrupolar electromagnetic polarizabilities. By fitting the formula of the unpolarized differential effective section in order ω 5 to the experimental data we obtained modified values of α, β, but still in accordance with the order α > β. d) to establish an inequality based upon the analyticity properties of the Compton invariant amplitudes between expressions that include measurable physical variables, static properties of the nucleon and integrals on the effective differential section for the process γ + p → γ' + p'. (author)
Two-Photon Exchange Effects in Elastic Electron-Proton Scattering
Energy Technology Data Exchange (ETDEWEB)
Johnson, Myriam James [Argonne National Lab. (ANL), Argonne, IL (United States)
2013-08-01
Two methods, Rosenbluth separation and polarization transfer, can be used to extract the proton form factor ratio μp G_{Ep}/G_{Mp}, but they do not yield the same results. It is thought that the disagreement is due to two photon exchange corrections to the differential cross sections. High precision proton Rosenbluth extractions were carried out at 102 kinematics points spanning 16 values of momentum transfer Q^{2}, from 0.40 to 5.76 GeV^{2}. Reduced cross sections were found to 1.1% or better for Q^{2} less than 3 GeV^{2} increasing to 4% at 5.76 GeV^{2} The form factor ratios were determined to 1:5-3% for Q^{2} < 1.5 GeV^{2}, increasing to 9% by 3 GeV^{2} and rapidly above. Our data agrees with prior Rosenbluth, improving upon it the 1.0 - 2.0 GeV^{2} range to conclusively show a separation from polarization transfer where it had not been certain before. In addition, reduced cross sections at each Q^{2} were tested for nonlinearity in the angular variable. Such a departure from linearity would be a signature of two photon exchange effects, and prior data had not been sufficiently precise to show nonzero curvature. Our data begins to hint at negative curvature but does not yet show a significant departure from zero.
Photon detectors for epithermal neutron scattering at high-ω and low-q
International Nuclear Information System (INIS)
Pietropaolo, A.; Senesi, R.; Tardocchi, M.; Andreani, C.; Gorini, G.
2004-01-01
Inelastic epithermal neutron scattering at high energy (ℎω≥1 eV) and low wave vector (q≤10 A -1 ) transfers is the unique technique for the investigation of high-energy excitations in a variety of systems, ranging from magnetic materials to semiconductors. The key issue in order to make these measurements feasible on inverse geometry spectrometers, is to develop suitable detection systems for neutrons in the energy range 1-100 eV. The Resonance Detector Spectrometer configuration has to be considered as the most promising approach for electron Volt neutron spectroscopy. This configuration will be employed in the new low angle detector bank, VLAD, planned for VESUVIO spectrometer operating at ISIS source
Energy Technology Data Exchange (ETDEWEB)
Costescu, A [Department of Physics, University of Bucharest, MG11, Bucharest-Magurele 76900 (Romania); Spanulescu, S [Department of Physics, University of Bucharest, MG11, Bucharest-Magurele 76900 (Romania); Stoica, C [Department of Physics, University of Bucharest, MG11, Bucharest-Magurele 76900 (Romania)
2007-08-14
The right expressions of the nonrelativistic K-shell Rayleigh scattering amplitudes and cross-sections are obtained by using the Coulomb Green's function method. Our analytical result does not have the spurious poles that occur in the old nonrelativistic result with retardation (Gavrila and Costescu 1970 Phys. Rev. A 2 1752). Starting from the expression of the second-order S-matrix element for the case of the elastic scattering of photons by K-shell bound electrons, we obtain the correct nonrelativistic Rayleigh angular distribution (valid for photon energies {omega} up to {alpha}Zm) by removing the relativistic higher order terms in {alpha}Z and {omega}/m. The imaginary part of the Rayleigh amplitudes is obtained for any scattering angles in a closed form in terms of elementary functions. Thereby a simple formula for the exact nonrelativistic photoeffect total cross-section is obtained via the optical theorem, giving significantly better predictions than Fischer's nonrelativistic photoeffect formula. Comparing the predictions given by our formulae with the full relativistic numerical calculations of Kissel et al (Phys. Rev. 1980 A 22 1970), and with experimental results, a fairly good agreement within 10% is found for the angular distribution of Rayleigh scattering for photon energies up to 200 keV and both below and above the first resonance.
Polarized photon scattering of 52Cr: Determining the parity of dipole states
Krishichayan, Fnu; Bhike, M.; Tornow, W.
2014-03-01
Observation of dipole states in nuclei are important because they provide information on various collective and single-particle nuclear excitation modes, e.g., pygmy dipole resonance (PDR) and spin-flip M1 resonance. The PDR has been extensively studied in the higher and medium mass region, whereas not much information is available around the low mass (A ~ 50) region where, apparently,the PDR starts to form. The present photoresponse of 52Cr has been investigated to test the evolution of the PDR in a nucleus with a small number of excess neutrons as well as to look for spin-flip M1 resonance excitation mode. Spin-1 states in 52Cr between 5.0 to 9.5 MeV excitation energy were excited by exploiting fully polarized photons using the (γ ,γ') nuclear resonance fluorescence technique, a completely model-independent electromagnetic method. The de-excitation γ-rays were detected using a HPGe array. The experiment was carried out using the HIGS facility at TUNL. Results of unambiguous parity determinations of dipole states in 52Cr will be presented.
International Nuclear Information System (INIS)
Kainz, Kristofer; Firat, Selim; Wilson, J Frank; Schultz, Christopher; Siker, Malika; Wang, Andrew; Olson, Dan; Allen Li, X
2015-01-01
We compare the quality of photon IMRT (helical tomotherapy) with classic proton plans for brain, head and neck tumors, in terms of target dose uniformity and conformity along with organ-at-risk (OAR) sparing. Plans were created for twelve target volumes among eight cases. All patients were originally planned and treated using helical tomotherapy. Proton plans were generated using a passively-scattered beam model with a maximum range of 32 g cm −2 (225 MeV), range modulation in 0.5 g cm −2 increments and range compensators with 4.8 mm milling tool diameters. All proton plans were limited to two to four beams. Plan quality was compared using uniformity index (UI), conformation number (CN) and a EUD-based plan quality index (fEUD). For 11 of the 12 targets, UI was improved for the proton plan; on average, UI was 1.05 for protons versus 1.08 for tomotherapy. For 7 of the 12 targets, the tomotherapy plan exhibited more favorable CN. For proximal OARs, the improved dose conformity to the target volume from tomotherapy led to a lower maximum dose. For distal OARs, the maximum dose was much lower for proton plans. For 6 of the 8 cases, near-total avoidance for distal OARs provided by protons leads to improved fEUD. However, if distal OARs are excluded in the fEUD calculation, the proton plans exhibit better fEUD in only 3 of the 8 cases. The distal OAR sparing and target dose uniformity are generally better with passive-scatter proton planning than with photon tomotherapy; proton therapy may be preferred if the clinician deems those attributes critical. However, tomotherapy may serve equally as well as protons for cases where superior target dose conformity from tomotherapy leads to plan quality nearly identical to or better than protons and for cases where distal OAR sparing is not concerning. (paper)
A systematic approach to robust preconditioning for gradient-based inverse scattering algorithms
International Nuclear Information System (INIS)
Nordebo, Sven; Fhager, Andreas; Persson, Mikael; Gustafsson, Mats
2008-01-01
This paper presents a systematic approach to robust preconditioning for gradient-based nonlinear inverse scattering algorithms. In particular, one- and two-dimensional inverse problems are considered where the permittivity and conductivity profiles are unknown and the input data consist of the scattered field over a certain bandwidth. A time-domain least-squares formulation is employed and the inversion algorithm is based on a conjugate gradient or quasi-Newton algorithm together with an FDTD-electromagnetic solver. A Fisher information analysis is used to estimate the Hessian of the error functional. A robust preconditioner is then obtained by incorporating a parameter scaling such that the scaled Fisher information has a unit diagonal. By improving the conditioning of the Hessian, the convergence rate of the conjugate gradient or quasi-Newton methods are improved. The preconditioner is robust in the sense that the scaling, i.e. the diagonal Fisher information, is virtually invariant to the numerical resolution and the discretization model that is employed. Numerical examples of image reconstruction are included to illustrate the efficiency of the proposed technique
International Nuclear Information System (INIS)
Breunig, Hans Georg; Weinigel, Martin; Bückle, Rainer; Kellner-Höfer, Marcel; König, Karsten; Lademann, Jürgen; Darvin, Maxim E; Sterry, Wolfram
2013-01-01
We report on in vivo coherent anti-Stokes Raman scattering spectroscopy (CARS), two-photon fluorescence and second-harmonic-generation imaging on human skin with a novel multimodal clinical CARS/multiphoton tomograph. CARS imaging is realized by a combination of femtosecond pulses with broadband continuum pulses generated by a photonic crystal fiber. The images reveal the microscopic distribution of (i) non-fluorescent lipids, (ii) endogenous fluorophores and (iii) the collagen network inside the human skin in vivo with subcellular resolution. Examples of healthy as well as cancer-affected skin are presented. (letter)
Breunig, Hans Georg; Weinigel, Martin; Bückle, Rainer; Kellner-Höfer, Marcel; Lademann, Jürgen; Darvin, Maxim E.; Sterry, Wolfram; König, Karsten
2013-02-01
We report on in vivo coherent anti-Stokes Raman scattering spectroscopy (CARS), two-photon fluorescence and second-harmonic-generation imaging on human skin with a novel multimodal clinical CARS/multiphoton tomograph. CARS imaging is realized by a combination of femtosecond pulses with broadband continuum pulses generated by a photonic crystal fiber. The images reveal the microscopic distribution of (i) non-fluorescent lipids, (ii) endogenous fluorophores and (iii) the collagen network inside the human skin in vivo with subcellular resolution. Examples of healthy as well as cancer-affected skin are presented.
Li, Xuesong; Lam, Wen Jiun; Cao, Zhe; Hao, Yan; Sun, Qiqi; He, Sicong; Mak, Ho Yi; Qu, Jianan Y.
2015-11-01
The primary goal of this study is to demonstrate that stimulated Raman scattering (SRS) as a new imaging modality can be integrated into a femtosecond (fs) nonlinear optical (NLO) microscope system. The fs sources of high pulse peak power are routinely used in multimodal nonlinear microscopy to enable efficient excitation of multiple NLO signals. However, with fs excitations, the SRS imaging of subcellular lipid and vesicular structures encounters significant interference from proteins due to poor spectral resolution and a lack of chemical specificity, respectively. We developed a unique NLO microscope of fs excitation that enables rapid acquisition of SRS and multiple two-photon excited fluorescence (TPEF) signals. In the in vivo imaging of transgenic C. elegans animals, we discovered that by cross-filtering false positive lipid signals based on the TPEF signals from tryptophan-bearing endogenous proteins and lysosome-related organelles, the imaging system produced highly accurate assignment of SRS signals to lipid. Furthermore, we demonstrated that the multimodal NLO microscope system could sequentially image lipid structure/content and organelles, such as mitochondria, lysosomes, and the endoplasmic reticulum, which are intricately linked to lipid metabolism.
Williams, G Jackson; Lee, Sooheyong; Walko, Donald A; Watson, Michael A; Jo, Wonhuyk; Lee, Dong Ryeol; Landahl, Eric C
2016-12-22
Nonlinear optical phenomena in semiconductors present several fundamental problems in modern optics that are of great importance for the development of optoelectronic devices. In particular, the details of photo-induced lattice dynamics at early time-scales prior to carrier recombination remain poorly understood. We demonstrate the first integrated measurements of both optical and structural, material-dependent quantities while also inferring the bulk impulsive strain profile by using high spatial-resolution time-resolved x-ray scattering (TRXS) on bulk crystalline gallium arsenide. Our findings reveal distinctive laser-fluence dependent crystal lattice responses, which are not described by previous TRXS experiments or models. The initial linear expansion of the crystal upon laser excitation stagnates at a laser fluence corresponding to the saturation of the free carrier density before resuming expansion in a third regime at higher fluences where two-photon absorption becomes dominant. Our interpretations of the lattice dynamics as nonlinear optical effects are confirmed by numerical simulations and by additional measurements in an n-type semiconductor that allows higher-order nonlinear optical processes to be directly observed as modulations of x-ray diffraction lineshapes.
International Nuclear Information System (INIS)
LaJohn, L A; Pratt, R H
2009-01-01
We discuss the increase in error with increasing nuclear charge Z in the use of the relativistic impulse approximation (RIA) for the calculation of Compton K-shell scattering doubly differential cross sections (DDCS). We also show that nonrelativistic (nr) expressions can be used to obtain accurate peak region DDCS at scattering angles less than about 35 0 even at incident photon energies ω i exceeding 1 MeV, if Z<30. This is possible because in the Compton peak region, as θ→0, a low momentum transfer limit is being approached.
Elastic and Raman scattering of 8.5-11.4 MeV photons from 159Tb, 165Ho, and 237Np
International Nuclear Information System (INIS)
Bar-Noy, T.; Moreh, R.
1977-01-01
Differential cross sections for elastic and inelastic Raman scattering from the deformed heavy nuclei 159 Tb, 165 Ho and 237 Np were measured at five energies between 8.5 and 11.4 MeV. Angular distributions at four angles between 90 0 and 140 0 for both elastic and inelastic scattering at 9.0 and 11.4 MeV were also measured. The monoenergetic photons were obtained from thermal neutron capture in Ni and Cr. All the angular distributions and the elastic and Raman scattering at the higher energies are in good overall agreement with theoretical predictions. The theory is based on a modified simple rotator model of the giant resonance in which the effect of Delbrueck scattering was included. A trend of both the elastic and Raman scattering at lower energies to be stronger than expected are suggested by the data. However, the ratio between the Raman and elastic scattering seem to be in good agreement with theory throughout the whole energy range. This shows that there is no need to introduce a direct nonresonant component to the imaginary part of the elastic scattering amplitude to explain the experimental data. (Auth.)
Energy Technology Data Exchange (ETDEWEB)
Pietralla, N., E-mail: pietralla@ikp.tu-darmstadt.d [Institut fuer Kernphysik, Technische Universitaet Darmstadt, 64289 Darmstadt (Germany); Nuclear Structure Laboratory, SUNY at Stony Brook, Stony Brook, NY 11794-3800 (United States); Institut fuer Kernphysik, Universitaet zu Koeln, 50937 Koeln (Germany); Li, T.C. [Nuclear Structure Laboratory, SUNY at Stony Brook, Stony Brook, NY 11794-3800 (United States); Fritzsche, M. [Institut fuer Kernphysik, Technische Universitaet Darmstadt, 64289 Darmstadt (Germany); Ahmed, M.W. [Triangle Universities Nuclear Laboratory (TUNL), Duke University, Durham, NC 27708 (United States); Ahn, T.; Costin, A. [Institut fuer Kernphysik, Technische Universitaet Darmstadt, 64289 Darmstadt (Germany); Nuclear Structure Laboratory, SUNY at Stony Brook, Stony Brook, NY 11794-3800 (United States); Institut fuer Kernphysik, Universitaet zu Koeln, 50937 Koeln (Germany); Enders, J. [Institut fuer Kernphysik, Technische Universitaet Darmstadt, 64289 Darmstadt (Germany); Li, J. [Duke Free Electron Laser Laboratory (DFELL), Duke University, Durham, NC 27708 (United States); Mueller, S.; Neumann-Cosel, P. von [Institut fuer Kernphysik, Technische Universitaet Darmstadt, 64289 Darmstadt (Germany); Pinayev, I.V. [Duke Free Electron Laser Laboratory (DFELL), Duke University, Durham, NC 27708 (United States); Ponomarev, V.Yu.; Savran, D. [Institut fuer Kernphysik, Technische Universitaet Darmstadt, 64289 Darmstadt (Germany); Tonchev, A.P.; Tornow, W.; Weller, H.R. [Triangle Universities Nuclear Laboratory (TUNL), Duke University, Durham, NC 27708 (United States); Werner, V. [A.W. Wright Nuclear Structure Laboratory (WNSL), Yale University, New Haven, CT (United States); Wu, Y.K. [Duke Free Electron Laser Laboratory (DFELL), Duke University, Durham, NC 27708 (United States); Zilges, A. [Institut fuer Kernphysik, Universitaet zu Koeln, 50937 Koeln (Germany)
2009-10-26
The Pb(gamma{sup -}>,gamma{sup '}) photon scattering reaction has been studied with the nearly monochromatic, linearly polarized photon beams at the High Intensity gamma-ray Source (HIgammaS) at the DFELL. Azimuthal scattering intensity asymmetries measured with respect to the polarization plane of the beam have been used for the first time to assign both the spin and parity quantum numbers of dipole excited states of {sup 206,207,208}Pb at excitation energies in the vicinity of 5.5 MeV. Evidence for dominant particle-core coupling is deduced from these results along with information on excitation energies and electromagnetic transition matrix elements. Implications of the existence of weakly coupled states built on highly excited core states in competition with 1homega single particle (hole) excitations at comparable energies are discussed.
Lawler, J. E.; Den Hartog, E. A.
2018-03-01
The Ar I and II branching ratio calibration method is discussed with the goal of improving the technique. This method of establishing a relative radiometric calibration is important in ongoing research to improve atomic transition probabilities for quantitative spectroscopy in astrophysics and other fields. Specific suggestions are presented along with Monte Carlo simulations of wavelength dependent effects from scattering/reflecting of photons in a hollow cathode.
Sakota, Daisuke; Takatani, Setsuo
2012-05-01
Optical properties of flowing blood were analyzed using a photon-cell interactive Monte Carlo (pciMC) model with the physical properties of the flowing red blood cells (RBCs) such as cell size, shape, refractive index, distribution, and orientation as the parameters. The scattering of light by flowing blood at the He-Ne laser wavelength of 632.8 nm was significantly affected by the shear rate. The light was scattered more in the direction of flow as the flow rate increased. Therefore, the light intensity transmitted forward in the direction perpendicular to flow axis decreased. The pciMC model can duplicate the changes in the photon propagation due to moving RBCs with various orientations. The resulting RBC's orientation that best simulated the experimental results was with their long axis perpendicular to the direction of blood flow. Moreover, the scattering probability was dependent on the orientation of the RBCs. Finally, the pciMC code was used to predict the hematocrit of flowing blood with accuracy of approximately 1.0 HCT%. The photon-cell interactive Monte Carlo (pciMC) model can provide optical properties of flowing blood and will facilitate the development of the non-invasive monitoring of blood in extra corporeal circulatory systems.
International Nuclear Information System (INIS)
Qattan, I. A.; Alsaad, A.
2011-01-01
The most recent electron-proton elastic scattering data were re-analyzed using an empirical parametrization of the two-photon-exchange (TPE) effect contributions to σ R . The TPE effect contribution F(Q 2 ,ε) was double Taylor series expanded as a polynomial of order n keeping only terms linear in ε to account for the experimentally observed and verified linearity of the Rosenbluth plots. We fix the ratio R=G Ep /G Mp to be that obtained from a fit to the recoil-polarization data and parametrize σ R first by a three-parameter formula (fit I) and then by a two-parameter formula (fit III). In contrast to previous analyses, the fit parameter G Mp 2 as obtained from these fits is either smaller or equal to the values obtained from our conventional Rosenbluth fit (fit II) but never larger. The ratio g(Q 2 )/G Mp 2 which represents the ratio of the TPE and one-photon-exchange (OPE) effect contributions to the intercept of σ R is large and it ranges 3%-88%. The ratio R 1γx2γ =τf(Q 2 )/G Ep 2 which represents the ratio of the TPE and OPE effect contributions to the slope of σ R is also large, reaching a value of 12.0-14.4 at Q 2 = 5.25 (GeV/c) 2 . The ratio R 1γx2γ as obtained from fits I and III is consistent, within error, with those obtained from previous analyses. Our formulas seem to explain the linearity of σ R . Moreover, our analysis shows that the extracted G Ep 2 and G Mp 2 using the conventional Rosenbluth separation method can in fact be broken into the usual OPE and TPE contributions. Therefore, σ R can in fact be derived under weaker conditions than those imposed by the Born approximation. Our results show that the TPE amplitudes, g(Q 2 )/G Mp 2 and f(Q 2 )/G Mp 2 , are sizable and grow with Q 2 value up to Q 2 ∼6 (GeV/c) 2 in agreement with previous studies. A revision of and comparison to previous analyses are also presented.
Directory of Open Access Journals (Sweden)
JONG WOON KIM
2014-04-01
In this paper, we introduce a modified scattering kernel approach to avoid the unnecessarily repeated calculations involved with the scattering source calculation, and used it with parallel computing to effectively reduce the computation time. Its computational efficiency was tested for three-dimensional full-coupled photon-electron transport problems using our computer program which solves the multi-group discrete ordinates transport equation by using the discontinuous finite element method with unstructured tetrahedral meshes for complicated geometrical problems. The numerical tests show that we can improve speed up to 17∼42 times for the elapsed time per iteration using the modified scattering kernel, not only in the single CPU calculation but also in the parallel computing with several CPUs.
Energy Technology Data Exchange (ETDEWEB)
Fathollahi Khalkhali, T., E-mail: tfathollahi@aeoi.org.ir; Bananej, A.
2016-12-16
In this study, we analyze complete photonic band gap properties of two-dimensional dielectric-plasma photonic crystals with triangular and square lattices, composed of plasma rods with different geometrical shapes in the anisotropic tellurium background. Using the finite-difference time-domain method we discuss the maximization of the complete photonic band gap width as a function of plasma frequency and plasma rods parameters with different shapes and orientations. The numerical results demonstrate that our proposed structures represent significantly wide complete photonic band gaps in comparison to previously studied dielectric-plasma photonic crystals. - Highlights: • In this paper, we have investigated plasma photonic crystals. • Plasma is a kind of dispersive medium with its equivalent refractive index related to the frequency of an incident EM wave. • In this work, our simulations are performed using the Meep implementation of the finite-difference time-domain (FDTD) method. • For this study, the lattice structures investigated are triangular and square. • Extensive calculations reveal that almost all of these structures represent wide complete band gaps.
International Nuclear Information System (INIS)
Fathollahi Khalkhali, T.; Bananej, A.
2016-01-01
In this study, we analyze complete photonic band gap properties of two-dimensional dielectric-plasma photonic crystals with triangular and square lattices, composed of plasma rods with different geometrical shapes in the anisotropic tellurium background. Using the finite-difference time-domain method we discuss the maximization of the complete photonic band gap width as a function of plasma frequency and plasma rods parameters with different shapes and orientations. The numerical results demonstrate that our proposed structures represent significantly wide complete photonic band gaps in comparison to previously studied dielectric-plasma photonic crystals. - Highlights: • In this paper, we have investigated plasma photonic crystals. • Plasma is a kind of dispersive medium with its equivalent refractive index related to the frequency of an incident EM wave. • In this work, our simulations are performed using the Meep implementation of the finite-difference time-domain (FDTD) method. • For this study, the lattice structures investigated are triangular and square. • Extensive calculations reveal that almost all of these structures represent wide complete band gaps.
Chen, Zhe Jay; Nath, Ravinder
2010-10-21
The aim of this study was to perform a systematic comparison of the dose-rate constant (Λ) determined by the photon spectrometry technique (PST) with the consensus value ((CON)Λ) recommended by the American Association of Physicists in Medicine (AAPM) for 21 low-energy photon-emitting interstitial brachytherapy sources. A total of 63 interstitial brachytherapy sources (21 different models with 3 sources per model) containing either (125)I (14 models), (103)Pd (6 models) or (131)Cs (1 model) were included in this study. A PST described by Chen and Nath (2007 Med. Phys. 34 1412-30) was used to determine the dose-rate constant ((PST)Λ) for each source model. Source-dependent variations in (PST)Λ were analyzed systematically against the spectral characteristics of the emitted photons and the consensus values recommended by the AAPM brachytherapy subcommittee. The values of (PST)Λ for the encapsulated sources of (103)Pd, (125)I and (131)Cs varied from 0.661 to 0.678 cGyh(-1) U(-1), 0.959 to 1.024 cGyh(-1)U(-1) and 1.066 to 1.073 cGyh(-1)U(-1), respectively. The relative variation in (PST)Λ among the six (103)Pd source models, caused by variations in photon attenuation and in spatial distributions of radioactivity among the source models, was less than 3%. Greater variations in (PST)Λ were observed among the 14 (125)I source models; the maximum relative difference was over 6%. These variations were caused primarily by the presence of silver in some (125)I source models and, to a lesser degree, by the variations in photon attenuation and in spatial distribution of radioactivity among the source models. The presence of silver generates additional fluorescent x-rays with lower photon energies which caused the (PST)Λ value to vary from 0.959 to 1.019 cGyh(-1)U(-1) depending on the amount of silver used by a given source model. For those (125)I sources that contain no silver, their (PST)Λ was less variable and had values within 1% of 1.024 cGyh(-1)U(-1). For the 16
Energy Technology Data Exchange (ETDEWEB)
Kuhn, Markus
2008-09-23
The electromagnetic form factors are crucial for our understanding of the inner structure of the proton. Recently it has become feasible to measure them by the use of polarisation transfer techniques in addition to the traditional Rosenbluth separation method. Thereby emerged an incompatibility of the results obtained by these two different experimental methods. It is commonly assumed that the discrepance is induced by higher order corrections to the cross section, especially through two-photon exchange processes. Unfortunately these processes cannot be calculated in a model independent manner because off-shell photon nucleon vertices arise. Effective chiral lagrangians contain already local two-photon couplings and therefore seem exceptionally well suited to study the anomaly contribution to the two-photon exchange. These couplings give two-photon exchange contributions that can be understood as the coupling of the nucleon to pions, decaying into two virtual photons. A particular contribution emerges from the chiral anomaly of QCD, that describes the two-photon decay of the neutral pion. The most important goal of this work is the calculation of the contribution arising from the anomaly to the elastic electron-proton scattering. The results are expected to be widely model independent since the anomaly directly reflects a QCD property. Based on the Skyrme model the protons are realized as soliton solutions in effective chiral theories. The next to leading order contribution to the cross section is given by the interference between the one- and two-photon exchange. The latter contains an ultraviolet divergence, which is renormalized by a local effective counterterm. This counterterm contributes to the width of the neutral pion decay which determines the finite part of the counterterm coefficient. The affect of the anomaly to the Rosenbluth separation of the electromagnetic form factors as well as the discrepance regarding the polarization measurements is extensively
International Nuclear Information System (INIS)
Thanh, Tran Thien; Nguyen, Vo Hoang; Chuong, Huynh Dinh; Tran, Le Bao; Tam, Hoang Duc; Binh, Nguyen Thi; Tao, Chau Van
2015-01-01
This article focuses on the possible application of a "1"3"7Cs low-radioactive source (5 mCi) and a NaI(Tl) detector for measuring the saturation thickness of solid cylindrical steel targets. In order to increase the reliability of the obtained experimental results and to verify the detector response function of Compton scattering spectrum, simulation using Monte Carlo N-particle (MCNP5) code is performed. The obtained results are in good agreement with the response functions of the simulation scattering and experimental scattering spectra. On the basis of such spectra, the saturation depth of a steel cylinder is determined by experiment and simulation at about 27 mm using gamma energy of 662 keV ("1"3"7Cs) at a scattering angle of 120°. This study aims at measuring the diameter of solid cylindrical objects by gamma-scattering technique. - Highlights: • This study aims a possible application a "1"3"7Cs low-radioactive source (5 mCi) and a NaI(Tl) detector for measuring the saturation thickness of solid cylindrical steel targets by gamma-scattering technique. • Monte Carlo N-particle (MCNP5) code is performed to verify on the detector response function of Compton scattering spectrum. • The results show a good agreement in response function of the experimental and simulation scattering spectra. • The saturation depth of a steel cylinder is determined by experiment and simulation at about 27 mm using gamma energy of 662 keV ("1"3"7Cs) at a scattering angle of 120°.
Energy Technology Data Exchange (ETDEWEB)
Andreev, V.; Belousov, A.; Fomenko, A.; Gogitidze, N.; Lebedev, A.; Malinovski, E.; Rusakov, S.; Vazdik, Y. [Lebedev Physical Institute, Moscow (Russian Federation); Baghdasaryan, A.; Zohrabyan, H. [Yerevan Physics Institute, Yerevan (Armenia); Begzsuren, K.; Ravdandorj, T.; Tseepeldorj, B. [Institute of Physics and Technology of the Mongolian Academy of Sciences, Ulaanbaatar (Mongolia); Belov, P.; Brinkmann, M.; Britzger, D.; Campbell, A.J.; Dodonov, V.; Eckerlin, G.; Elsen, E.; Fleischer, M.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Gouzevitch, M.; Haidt, D.; Kleinwort, C.; Krueger, K.; Levonian, S.; Lipka, K.; List, B.; List, J.; Lobodzinski, B.; Meyer, A.B.; Meyer, J.; Niebuhr, C.; Olsson, J.E.; Ozerov, D.; Pahl, P.; Petrukhin, A.; Pirumov, H.; Pitzl, D.; Placakyte, R.; Radescu, V.; Schmitt, S.; Sefkow, F.; Shushkevich, S.; South, D.; Steder, M.; Wuensch, E. [DESY, Hamburg (Germany); Boudry, V.; Specka, A. [LLR, Ecole Polytechnique, CNRS/IN2P3, Palaiseau (France); Brandt, G. [Oxford University, Department of Physics, Oxford (United Kingdom); Brisson, V.; Jacquet, M.; Pascaud, C.; Zhang, Z.; Zomer, F. [LAL, Universite Paris-Sud, CNRS/IN2P3, Orsay (France); Buniatyan, A.; Huber, F.; Sauter, M.; Schoening, A. [Universitaet Heidelberg, Physikalisches Institut, Heidelberg (Germany); Bylinkin, A.; Bystritskaya, L.; Fedotov, A.; Rostovtsev, A. [Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Cantun Avila, K.B.; Contreras, J.G. [CINVESTAV, Departamento de Fisica Aplicada, Merida, Yucatan (Mexico); Ceccopieri, F.; Favart, L.; Grebenyuk, A.; Hreus, T.; Janssen, X.; Roosen, R.; Mechelen, P. van [Brussels and Universiteit Antwerpen, Inter-University Institute for High Energies ULB-VUB, Antwerp (Belgium); Cerny, K.; Pokorny, B.; Polifka, R.; Salek, D.; Valkarova, A.; Zacek, J.; Zlebcik, R. [Charles University, Faculty of Mathematics and Physics, Prague (Czech Republic); Chekelian, V.; Grindhammer, G.; Kiesling, C. [Max-Planck-Institut fuer Physik, Munich (Germany); Dainton, J.B.; Gabathuler, E.; Greenshaw, T.; Klein, M.; Kostka, P.; Kretzschmar, J.; Laycock, P.; Maxfield, S.J.; Mehta, A.; Patel, G.D. [University of Liverpool, Department of Physics, Liverpool (United Kingdom); Daum, K.; Meyer, H. [Fachbereich C, Universitaet Wuppertal, Wuppertal (Germany); Diaconu, C.; Hoffmann, D.; Sauvan, E.; Vallee, C. [CPPM, Aix-Marseille Univ, CNRS/IN2P3, Marseille (France); Dobre, M.; Rotaru, M. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Dossanov, A. [Universitaet Hamburg, Institut fuer Experimentalphysik, Hamburg (Germany); Max-Planck-Institut fuer Physik, Munich (Germany); Egli, S.; Horisberger, R. [Paul Scherrer Institut, Villigen (Switzerland); Feltesse, J.; Perez, E.; Schoeffel, L. [CEA, DSM/Irfu, CE-Saclay, Gif-sur-Yvette (France); Ferencei, J. [Slovak Academy of Sciences, Institute of Experimental Physics, Kosice (Slovakia); Goerlich, L.; Mikocki, S.; Nowak, G.; Sopicki, P.; Turnau, J. [Institute for Nuclear Physics, Cracow (Poland); Grab, C. [Institut fuer Teilchenphysik, ETH, Zurich (Switzerland); Henderson, R.C.W. [University of Lancaster, Department of Physics, Lancaster (United Kingdom); Herbst, M.; Schultz-Coulon, H.C. [Kirchhoff-Institut fuer Physik, Universitaet Heidelberg, Heidelberg (Germany); Hladky, J.; Reimer, P. [Academy of Sciences of the Czech Republic, Institute of Physics, Prague (Czech Republic); Jung, H. [Brussels and Universiteit Antwerpen, Inter-University Institute for High Energies ULB-VUB, Antwerp (Belgium); DESY, Hamburg (Germany); Kapichine, M.; Lytkin, L.; Morozov, A.; Spaskov, V. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Kogler, R.; Nowak, K. [Universitaet Hamburg, Institut fuer Experimentalphysik, Hamburg (Germany); Landon, M.P.J.; Rizvi, E.; Traynor, D. [University of London, School of Physics and Astronomy, Queen Mary, London (GB); Lange, W.; Naumann, T. [DESY, Zeuthen (DE); Martyn, H.U. [I. Physikalisches Institut der RWTH, Aachen (DE); Mueller, K.; Robmann, P.; Straumann, U.; Truoel, P. [Physik-Institut der Universitaet Zuerich, Zurich (CH); Newman, P.R.; Thompson, P.D. [School of Physics and Astronomy, University of Birmingham, Birmingham (GB); Picuric, I.; Raicevic, N. [University of Montenegro, Faculty of Science, Podgorica (ME); Povh, B. [Max-Planck-Institut fuer Kernphysik, Heidelberg (DE); Sankey, D.P.C. [STFC, Rutherford Appleton Laboratory, Didcot, Oxfordshire (GB); Soloviev, Y. [DESY, Hamburg (DE); Lebedev Physical Institute, Moscow (RU); Stella, B. [Dipartimento di Fisica Universita di Roma Tre (IT); INFN Roma 3, Rome (IT); Sykora, T. [Brussels and Universiteit Antwerpen, Inter-University Institute for High Energies ULB-VUB, Antwerp (BE); Charles University, Faculty of Mathematics and Physics, Prague (CZ); Tsakov, I. [Institute for Nuclear Research and Nuclear Energy, Sofia (BG); Wegener, D. [Institut fuer Physik, TU Dortmund, Dortmund (DE); Collaboration: H1 Collaboration
2014-06-15
Measurements of normalised cross sections for the production of photons and neutrons at very small angles with respect to the proton beam direction in deep-inelastic ep scattering at HERA are presented as a function of the Feynman variable x{sub F} and of the centre-of-mass energy of the virtual photon-proton system W. The data are taken with the H1 detector in the years 2006 and 2007 and correspond to an integrated luminosity of 131 pb{sup -1}. The measurement is restricted to photons and neutrons in the pseudorapidity range η > 7.9 and covers the range of negative four momentum transfer squared at the positron vertex 6 < Q{sup 2} < 100 GeV{sup 2}, of inelasticity 0.05 < y < 0.6 and of 70 < W < 245 GeV. To test the Feynman scaling hypothesis the W dependence of the x{sub F} dependent cross sections is investigated. Predictions of deep-inelastic scattering models and of models for hadronic interactions of high energy cosmic rays are compared to the measured cross sections. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Zaraket, H
2000-06-01
This work is devoted to photon and dilepton production in a quark gluon plasma. The theoretical framework in which the study is carried out is Thermal Field Theory, more precisely the hard thermal loop effective theory. Several features of the observables preclude a straightforward application of the effective theory and new tools had to be developed such as the counter term method to avoid double counting. The first part of my study concerns static virtual photon production where I show that important physical contributions are missing in the effective theory at one loop level and hence a two loop calculation is indispensable. Furthermore I give an analytic leading logarithmic estimate of this two loop result showing clearly the insufficiency of the effective theory. The second part of the work focuses on real and quasi real photon production. Again, important contributions arise at two loop level due to collinear divergences. For high mass dilepton the two loop calculation is sufficient. On the other hand, near the light cone photon production rate is non perturbative. Getting closer to the light cone coherent scattering effects (Landau-Pomeranchuk-Migdal effect) arise, which imply the resummation of an infinite series of diagrams. Still nearer the light cone we found a dependence on the non perturbative magnetic mass due to infrared singularities. (author)
International Nuclear Information System (INIS)
Suric, T.; Pisk, K.; Pratt, R.H.
1996-01-01
We examine the charge (Z) dependence of the nonrelativistic high energy limit for the double to total ionization ratio by Compton scattering of a photon, as well as by the photoeffect, utilizing our approach based on the impulse approximation or on the generalized shake-off theory. For all Z our high energy Compton ratio is about half the corresponding photoeffect ratio, calculated using the same assumptions or, alternatively, the ratio of double ionization by Compton scattering to double ionization by the photoeffect is about half the ratio for single ionization. We conclude that all current Compton calculations are consistent with this result, and we show that the recent calculation of Amusia and Mikhailov [Phys. Lett. A 199 (1995) 209] corresponds to our high Z results. (orig.)
Saranathan, Vinodkumar; Forster, Jason D; Noh, Heeso; Liew, Seng-Fatt; Mochrie, Simon G J; Cao, Hui; Dufresne, Eric R; Prum, Richard O
2012-10-07
Non-iridescent structural colours of feathers are a diverse and an important part of the phenotype of many birds. These colours are generally produced by three-dimensional, amorphous (or quasi-ordered) spongy β-keratin and air nanostructures found in the medullary cells of feather barbs. Two main classes of three-dimensional barb nanostructures are known, characterized by a tortuous network of air channels or a close packing of spheroidal air cavities. Using synchrotron small angle X-ray scattering (SAXS) and optical spectrophotometry, we characterized the nanostructure and optical function of 297 distinctly coloured feathers from 230 species belonging to 163 genera in 51 avian families. The SAXS data provided quantitative diagnoses of the channel- and sphere-type nanostructures, and confirmed the presence of a predominant, isotropic length scale of variation in refractive index that produces strong reinforcement of a narrow band of scattered wavelengths. The SAXS structural data identified a new class of rudimentary or weakly nanostructured feathers responsible for slate-grey, and blue-grey structural colours. SAXS structural data provided good predictions of the single-scattering peak of the optical reflectance of the feathers. The SAXS structural measurements of channel- and sphere-type nanostructures are also similar to experimental scattering data from synthetic soft matter systems that self-assemble by phase separation. These results further support the hypothesis that colour-producing protein and air nanostructures in feather barbs are probably self-assembled by arrested phase separation of polymerizing β-keratin from the cytoplasm of medullary cells. Such avian amorphous photonic nanostructures with isotropic optical properties may provide biomimetic inspiration for photonic technology.
Photon Collider Physics with Real Photon Beams
International Nuclear Information System (INIS)
Gronberg, J; Asztalos, S
2005-01-01
Photon-photon interactions have been an important probe into fundamental particle physics. Until recently, the only way to produce photon-photon collisions was parasitically in the collision of charged particles. Recent advances in short-pulse laser technology have made it possible to consider producing high intensity, tightly focused beams of real photons through Compton scattering. A linear e + e - collider could thus be transformed into a photon-photon collider with the addition of high power lasers. In this paper they show that it is possible to make a competitive photon-photon collider experiment using the currently mothballed Stanford Linear Collider. This would produce photon-photon collisions in the GeV energy range which would allow the discovery and study of exotic heavy mesons with spin states of zero and two
International Nuclear Information System (INIS)
Duda, J.; Hoefner, F.W.; Jung, M.; Kleissler, R.; Kueck, H.; Leu, P.; Marne, K.D. de; Munk, B.; Vogl, W.; Wedemeyer, R.
1982-11-01
Differential cross sections of proton Compton scattering have been measured at the Bonn 2.5 GeV synchrotron. The experiment covers photon laboratory energies between 1.2 GeV and 1.7 GeV and the square of the four-momentum transfer ranges from t = -0.17 GeV 2 to -0.98 GeV 2 corresponding to c.m. scattering angles between 35 0 and 80 0 . The cross sections exhibit a forward peak followed by a monotone fall-off up to the largest measured vertical stroketvertical stroke-values. Fits of the form dsigma/dt = A.exp(Bt) to the data points with vertical stroketvertical stroke 2 yield forward cross sections A, which are consistent with the 0 0 cross sections calculated from the measured total photon-proton cross section. The average slope is B = 5.6 +- 0.14 GeV 2 . (orig.)
Directory of Open Access Journals (Sweden)
Mehravar Rafati
2017-01-01
Conclusion: The simulation and the clinical studies showed that the new approach could be better performance than DEW, TEW methods, according to values of the contrast, and the SNR for scatter correction.
International Nuclear Information System (INIS)
Hashimoto, Jun; Kubo, Atsushi; Ogawa, Koichi; Ichihara, Takashi; Motomura, Nobutoku; Takayama, Takuzo; Iwanaga, Shiro; Mitamura, Hideo; Ogawa, Satoshi
1998-01-01
A practical method for scatter and attenuation compensation was employed in thallium-201 myocardial single-photon emission tomography (SPET or ECT) with the triple-energy-window (TEW) technique and an iterative attenuation correction method by using a measured attenuation map. The map was reconstructed from technetium-99m transmission CT (TCT) data. A dual-headed SPET gamma camera system equipped with parallel-hole collimators was used for ECT/TCT data acquisition and a new type of external source named ''sheet line source'' was designed for TCT data acquisition. This sheet line source was composed of a narrow long fluoroplastic tube embedded in a rectangular acrylic board. After injection of 99m Tc solution into the tube by an automatic injector, the board was attached in front of the collimator surface of one of the two detectors. After acquiring emission and transmission data separately or simultaneously, we eliminated scattered photons in the transmission and emission data with the TEW method, and reconstructed both images. Then, the effect of attenuation in the scatter-corrected ECT images was compensated with Chang's iterative method by using measured attenuation maps. Our method was validated by several phantom studies and clinical cardiac studies. The method offered improved homogeneity in distribution of myocardial activity and accurate measurements of myocardial tracer uptake. We conclude that the above correction method is feasible because a new type of 99m Tc external source may not produce truncation in TCT images and is cost-effective and easy to prepare in clinical situations. (orig.)
International Nuclear Information System (INIS)
Garg, S.B.
1990-01-01
A 75 group neutron-photon coupled cross-section library has been developed for 42 reactor nuclides utilizing the basic cross-section files - ENDF/B-IV for neutrons and DLC-7F for photons. 50 neutron energy groups and gamma energy groups are included in this library which should be well suited to carry out safety, shielding and core physics studies of nuclear reactors based on fission or fusion processes. This library is also adequate for oil logging and mineral exploration investigations. (author). 11 refs., 3 tabs
Hadron production in photon-photon collisions
International Nuclear Information System (INIS)
Pandita, P.N.; Singh, Y.
1976-01-01
We analyze deep-inelastic photon-photon collisions via the two-photon mechanism in electron-positron (-electron) colliding beams in a form especially suitable for experimental analysis. It is shown that by a helicity analysis similar to that used in electroproduction experiments, we can separate five of the eight structure functions describing the process γ* + γ* → hadrons. The helicity cross sections for this process and for the process with one real photon (inelastic electron-photon scattering) are related to structure functions, and are evaluated using quark light-cone algebra. There are anomalous contributions to the structure functions for the inelastic electron-photon scattering which arise both in parton as well as generalized vector-meson-dominance models. This suggests a connection between these two types of models for photon-photon scattering. Further, we use vector-meson dominance to construct a sum rule for sigma/sub gamma//sub gamma/ /sub arrow-right/ from which it is estimated that roughly 20% of the cross section should be built up from higher-mass vector states. Using a spectral representation for the total transverse cross section, and the ''aligned-jet'' vector-dominance model we achieve a connection, via a ''correspondence principle,'' with the parton model for the hadron multiplicities in photon-photon collisions. We also comment on inclusive pion multiplicities and the approach to scaling for photon-photon processes in the light-cone algebra
Zeng, Lunwu; Xu, Jin; Wang, Chengen; Zhang, Jianhua; Zhao, Yuting; Zeng, Jing; Song, Runxia
2017-12-07
When space (time) translation symmetry is spontaneously broken, the space crystal (time crystal) forms; when permittivity and permeability periodically vary with space (time), the photonic crystal (photonic time crystal) forms. We proposed the concept of photonic time crystal and rewritten the Maxwell's equations. Utilizing Finite Difference Time Domain (FDTD) method, we simulated electromagnetic wave propagation in photonic time crystal and photonic space-time crystal, the simulation results show that more intensive scatter fields can obtained in photonic time crystal and photonic space-time crystal.
International Nuclear Information System (INIS)
Johnson, M S; McNabb, D P; Norman, E B
2007-01-01
Conclusions of this report are that there are 13 new transitions associated with NRF states in 239 Pu that have been discovered. These resonances are between 2- and 2.5-MeV relative to the ground state in 239 Pu. The strengths of most these resonances are between 15 and 20 eV b. This approximately is the strength required for using the transmission detection method for NRF [Pruet et al J. Appl. Phys. 99 12310 (2006)] for six-sigma alarm confidence levels. Future measurements on 239 Pu at higher photon energies are necessary to probe for NRF strengths at higher energies. Such resonances may be more advantageous to the NRF technique with FINDER if they are stronger or if the mean free path of these energetic photons is longer
Smetanin, I. V.; Erokhin, A. I.; Baranov, A. N.
2018-07-01
We report the results of the experimental and theoretical study of stimulated temperature scattering in toluene and hexane solutions of Ag-nanoparticles, as well as in pure toluene in the two-photon absorption regime. A four-wave mixing scheme with two counter-propagating pump waves of the same frequency is utilised to demonstrate the lasing effect and the amplification of the backscattered anti-Stokes signal. For the first time, we have measured anti-Stokes spectral shifts which turn out to appreciably exceed the Rayleigh line widths in those liquids. It is shown that the amplification effect is provided predominantly by thermally induced coherent polarisation oscillations, while the dynamic interference temperature grating causes the formation of a self-induced optical cavity inside the interaction region.
Wang, Qiang; Renema, Jelmer J; Engel, Andreas; van Exter, Martin P; de Dood, Michiel J A
2015-09-21
We propose an experiment to directly probe the local response of a superconducting single photon detector using a sharp metal tip in a scattering scanning near-field optical microscope. The optical absorption is obtained by simulating the tip-detector system, where the tip-detector is illuminated from the side, with the tip functioning as an optical antenna. The local detection efficiency is calculated by considering the recently introduced position-dependent threshold current in the detector. The calculated response for a 150 nm wide detector shows a peak close to the edge that can be spatially resolved with an estimated resolution of ∼ 20 nm, using a tip with parameters that are experimentally accessible.
Allen, Andrew; Zhang, Fan; Levine, Lyle; Ilavsky, Jan
2013-03-01
Ultra-small-angle X-ray scattering (USAXS) can probe microstructures over the nanometer-to-micrometer scale range. Through use of a small instrument entrance slit, X-ray photon correlation spectroscopy (XPCS) exploits the partial coherence of an X-ray synchrotron undulator beam to provide unprecedented sensitivity to the dynamics of microstructural change. In USAXS/XPCS studies, the dynamics of local structures in a scale range of 100 nm to 1000 nm can be related to an overall hierarchical microstructure extending from 1 nm to more than 1000 nm. Using a point-detection scintillator mode, the equilibrium dynamics at ambient temperature of small particles (which move more slowly than nanoparticles) in aqueous suspension have been quantified directly for the first time. Using a USAXS-XPCS scanning mode for non-equilibrium dynamics incipient processes within dental composites have been elucidated, prior to effects becoming detectable using any other technique. Use of the Advanced Photon Source, an Office of Science User Facility operated for the United States Department of Energy (U.S. DOE) Office of Science by Argonne National Laboratory, was supported by the U.S. DOE under Contract No. DE-AC02-06CH11357.
Energy Technology Data Exchange (ETDEWEB)
Klingler, S., E-mail: stefan.klingler@wmi.badw.de; Maier-Flaig, H.; Weiler, M. [Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, Walther-Meißner-Straße 8, 85748 Garching (Germany); Physik-Department, Technische Universität München, 85748 Garching (Germany); Gross, R.; Huebl, H.; Goennenwein, S. T. B. [Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, Walther-Meißner-Straße 8, 85748 Garching (Germany); Physik-Department, Technische Universität München, 85748 Garching (Germany); Nanosystems Initiative Munich (NIM), 80799 Munich (Germany); Hu, C.-M. [Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T2N2 (Canada)
2016-08-15
Microfocused Brillouin light scattering (BLS) and microwave absorption (MA) are used to study magnon-photon coupling in a system consisting of a split-ring microwave resonator and an yttrium iron garnet (YIG) film. The split-ring resonator is defined by optical lithography and loaded with a 1 μm-thick YIG film grown by liquid phase epitaxy. BLS and MA spectra of the hybrid system are simultaneously recorded as a function of the applied magnetic field magnitude and microwave excitation frequency. Strong coupling of the magnon and microwave resonator modes is found with a coupling strength of g{sub eff} /2π = 63 MHz. The combined BLS and MA data allow us to study the continuous transition of the hybridized modes from a purely magnonic to a purely photonic mode by varying the applied magnetic field and microwave frequency. Furthermore, the BLS data represent an up-conversion of the microwave frequency coupling to optical frequencies.
International Nuclear Information System (INIS)
Butson, M.J.; Cheung Tsang; Yu, P.K.N.
2002-01-01
18 MV X-ray beams used in radiotherapy have skin sparing properties as they produce a dose build-up effect whereby a smaller dose is delivered to the skin compared to dose at depth. Experimental results have shown that variations in the build-up dose significantly contribute to lepton contamination produced outside of the patient or the phantom in question. Monte Carlo simulations of 18 MV X-ray beams show that the surface dose contribution from in-phantom scatter alone is approximately 6% of the maximum dose. The contribution to dose from lepton contamination is found by comparison of Monte Carlo phantom photon scatter dose only and experimental data. Results show that the percentage contributions to dose from lepton contamination are approximately, 65%, 90% of dose at 0.05 mm (basal cell layer), 52%, 79% at 1 mm depth (dermal layer) and 15%, 26% at 10 mm depth (subcutaneous tissue) for 10 cmx10 cm 2 and 40 cmx40 cm 2 fields, respectively
Energy Technology Data Exchange (ETDEWEB)
Butson, M.J. E-mail: mbutson@guessmail.com; Cheung Tsang; Yu, P.K.N
2002-04-01
18 MV X-ray beams used in radiotherapy have skin sparing properties as they produce a dose build-up effect whereby a smaller dose is delivered to the skin compared to dose at depth. Experimental results have shown that variations in the build-up dose significantly contribute to lepton contamination produced outside of the patient or the phantom in question. Monte Carlo simulations of 18 MV X-ray beams show that the surface dose contribution from in-phantom scatter alone is approximately 6% of the maximum dose. The contribution to dose from lepton contamination is found by comparison of Monte Carlo phantom photon scatter dose only and experimental data. Results show that the percentage contributions to dose from lepton contamination are approximately, 65%, 90% of dose at 0.05 mm (basal cell layer), 52%, 79% at 1 mm depth (dermal layer) and 15%, 26% at 10 mm depth (subcutaneous tissue) for 10 cmx10 cm{sup 2} and 40 cmx40 cm{sup 2} fields, respectively.
Inverse photon-photon processes
International Nuclear Information System (INIS)
Carimalo, C.; Crozon, M.; Kesler, P.; Parisi, J.
1981-12-01
We here consider inverse photon-photon processes, i.e. AB → γγX (where A, B are hadrons, in particular protons or antiprotons), at high energies. As regards the production of a γγ continuum, we show that, under specific conditions the study of such processes might provide some information on the subprocess gg γγ, involving a quark box. It is also suggested to use those processes in order to systematically look for heavy C = + structures (quarkonium states, gluonia, etc.) showing up in the γγ channel. Inverse photon-photon processes might thus become a new and fertile area of investigation in high-energy physics, provided the difficult problem of discriminating between direct photons and indirect ones can be handled in a satisfactory way
Huang, Hao; Ouyang, Zhengbiao
2018-01-01
We propose a general method for eliminating the reflection of waves in 2 dimensional photonic crystal waveguides (2D-PCWs), a kind of 2D material, by introducing extra scatterers inside the 2D-PCWs. The intrinsic reflection in 2D-PCWs is compensated by the backward-scattered waves from these scatterers, so that the overall reflection is greatly reduced and the insertion loss is improved accordingly. We first present the basic theory for the compensation method. Then, as a demonstration, we give four examples of extremely-low-reflection and high-transmission 90°bent 2D-PCWs created according to the method proposed. In the four examples, it is demonstrated by plane-wave expansion method and finite-difference time-domain method that the 90°bent 2D-PCWs can have high transmission ratio greater than 90% in a wide range of operating frequency, and the highest transmission ratio can be greater than 99.95% with a return loss higher than 43 dB, better than that in other typical 90°bent 2D-PCWs. With our method, the bent 2D-PCWs can be optimized to obtain high transmission ratio at different operating wavelengths. As a further application of this method, a waveguide-based optical bridge for light crossing is presented, showing an optimum return loss of 46.85 dB, transmission ratio of 99.95%, and isolation rates greater than 41.77 dB. The method proposed provides also a useful way for improving conventional waveguides made of cables, fibers, or metal walls in the optical, infrared, terahertz, and microwave bands.
Azimuthal asymmetry in processes of nonlinear QED for linearly polarized photon
International Nuclear Information System (INIS)
Bajer, V.N.; Mil'shtejn, A.I.
1994-01-01
Cross sections of nonlinear QED processes (photon-photon scattering, photon splitting in a Coulomb field, and Delbrueck scattering) are considered for linearly polarized initial photon. The cross sections have sizeable azimuthal asymmetry. 15 refs.; 3 figs
International Nuclear Information System (INIS)
Adachi, Itaru; Doi, Kenji; Komori, Tsuyoshi; Hou, Nobuyoshi; Tabuchi, Koujirou; Matsui, Ritsuo; Sueyoshi, Kouzou; Utsunomiya, Keita; Narabayashi, Isamu
1998-01-01
This investigation was undertaken to study clinical usefulness of scatter and attenuation correction (SAC) of brain SPECT in infants to compare the standard reconstruction (STD). The brain SPECT was performed in 31 patients with 19 epilepsy, 5 cerebro-vascular disease, 2 brain tumor, 3 meningitis, 1 hydrocephalus and psychosis (mean age 5.0±4.9 years old). Many patients was necessary to be injected sedatives for restraining body motion after Technetium-99m hexamethylpropylene amine oxime ( 99m Tc-HMPAO) was injected at the convulsion or rest. Brain SPECT data were acquired with triple detector gamma camera (GCA-9300 Toshiba Japan). These data were reconstructed by filtered backprojection after the raw data were corrected by triple energy windows method of scatter correction and Chang filtered method of attenuation correction. The same data was reconstructed by filtered backprojection without these corrections. Both SAC and STD SPECT images were analyzed by the visual interpretation. The uptake ratio of cerebral basal nuclei was calculated by the counts of the thalamus or lenticular nuclei divided by the cortex. All images of SAC method were excellent than that of STD method. The thalamic uptake ratio in SAC method was higher than that of STD method (1.22±0.09>0.87±0.22 p 1.02±0.16 p<0.01). Transmission scan is the most suitable method of absorption correction. But the transmission scan is not adequate for examination of children, because this scan needs a lot of time and the infants are exposed by the line source radioisotope. It was concluded that these scatter and absorption corrections were most suitable method for brain SPECT in pediatrics. (author)
Energy Technology Data Exchange (ETDEWEB)
Adachi, Itaru; Doi, Kenji; Komori, Tsuyoshi; Hou, Nobuyoshi; Tabuchi, Koujirou; Matsui, Ritsuo; Sueyoshi, Kouzou; Utsunomiya, Keita; Narabayashi, Isamu [Osaka Medical Coll., Takatsuki (Japan)
1998-01-01
This investigation was undertaken to study clinical usefulness of scatter and attenuation correction (SAC) of brain SPECT in infants to compare the standard reconstruction (STD). The brain SPECT was performed in 31 patients with 19 epilepsy, 5 cerebro-vascular disease, 2 brain tumor, 3 meningitis, 1 hydrocephalus and psychosis (mean age 5.0{+-}4.9 years old). Many patients was necessary to be injected sedatives for restraining body motion after Technetium-99m hexamethylpropylene amine oxime ({sup 99m}Tc-HMPAO) was injected at the convulsion or rest. Brain SPECT data were acquired with triple detector gamma camera (GCA-9300 Toshiba Japan). These data were reconstructed by filtered backprojection after the raw data were corrected by triple energy windows method of scatter correction and Chang filtered method of attenuation correction. The same data was reconstructed by filtered backprojection without these corrections. Both SAC and STD SPECT images were analyzed by the visual interpretation. The uptake ratio of cerebral basal nuclei was calculated by the counts of the thalamus or lenticular nuclei divided by the cortex. All images of SAC method were excellent than that of STD method. The thalamic uptake ratio in SAC method was higher than that of STD method (1.22{+-}0.09>0.87{+-}0.22 p<0.01). The lenticular nuclear uptake ratio in SAC method was higher than that of STD method (1.26{+-}0.15>1.02{+-}0.16 p<0.01). Transmission scan is the most suitable method of absorption correction. But the transmission scan is not adequate for examination of children, because this scan needs a lot of time and the infants are exposed by the line source radioisotope. It was concluded that these scatter and absorption corrections were most suitable method for brain SPECT in pediatrics. (author)
International Nuclear Information System (INIS)
Lawrence, W.E.
1977-01-01
The general areas in which the investigations were carried out are transport properties and quasiparticle lifetimes in normal metals and superconductors. The more specific research projects upon which progress is reported are (a) the calculation of order parameter relaxation times in aluminum, (b) transport coefficients of the noble metals (emphasizing deviations from Matthiessen's rule), (c) variational transport calculations for a superconductor, (d) some general results on quasiparticle relaxation time anisotropy in polyvalent metals, and (e) a clarification of the roles of electron-electron and electron-phonon scattering in somple metals at low temperatures
Czech Academy of Sciences Publication Activity Database
Badelek, B.; Bloechinger, C.; Blümlein, J.; Boos, E.; Brinkman, R.; Burkhardt, H.; Bussey, P.; Carimalo, C.; Chýla, Jiří; Ciftci, A.K.
2004-01-01
Roč. 19, č. 30 (2004), s. 5097-5186 ISSN 0217-751X Institutional research plan: CEZ:AV0Z1010920 Keywords : photon collider * linear collider * gamma-gamma * photon-photon * photon electron * Compton scattering Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 1.054, year: 2004
Energy Technology Data Exchange (ETDEWEB)
Michael, Douglas Grant [Harvard U.
1990-01-01
The transverse momentum and energy-flow properties of forward ($x_F$ > 0) charged . hadrons and photons in deep inelastic muon scattering at 490GeV/c have been studied. Single particle transverse momentum and average transverse momentum as a function of $x_{Feynmen}$ are presented.Events are found to have a planar structure and transverse momentum spectra in and out of the event plane are presented. Data in the kinematic range $Q^2 > 3$ $GeV^2/c^2$ and 20 < W < 30 GeV/$c^2$ are used to search for two jets of particles in the forward direction. Energy and particle flow with.in the hadronic event plane are presented with several different cuts made on the data. A jet reconstruction algorithm is applied and properties of the forward jets are studied. For all plots, comparison is made with predictions from the Lund Monte Carlo tuned in different fashions. It is found that it is necessary to include hard QCD processes (gluon bremsstrahlung and photon-gluon fusion) in order to achieve good agreen1eut between the data and the Monte Carlo. In addition, it is shown that the data have more multi-jet events than predicted by the default version of the Lund ( 4.3) Monte Carlo.. It is suggested that it is necessary to increase the overall 'jettiness' by either increasing the primordial gluon distribution of the nucleon or adjusting the production cross section in the Monte Carlo. The possibility of an increased gluon distribution is presented and compared to data.
Energy Technology Data Exchange (ETDEWEB)
Poludniowski, Gavin G. [Joint Department of Physics, Division of Radiotherapy and Imaging, Institute of Cancer Research and Royal Marsden NHS Foundation Trust, Downs Road, Sutton, Surrey SM2 5PT, United Kingdom and Centre for Vision Speech and Signal Processing (CVSSP), Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom); Evans, Philip M. [Centre for Vision Speech and Signal Processing (CVSSP), Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom)
2013-04-15
Purpose: Monte Carlo methods based on the Boltzmann transport equation (BTE) have previously been used to model light transport in powdered-phosphor scintillator screens. Physically motivated guesses or, alternatively, the complexities of Mie theory have been used by some authors to provide the necessary inputs of transport parameters. The purpose of Part II of this work is to: (i) validate predictions of modulation transform function (MTF) using the BTE and calculated values of transport parameters, against experimental data published for two Gd{sub 2}O{sub 2}S:Tb screens; (ii) investigate the impact of size-distribution and emission spectrum on Mie predictions of transport parameters; (iii) suggest simpler and novel geometrical optics-based models for these parameters and compare to the predictions of Mie theory. A computer code package called phsphr is made available that allows the MTF predictions for the screens modeled to be reproduced and novel screens to be simulated. Methods: The transport parameters of interest are the scattering efficiency (Q{sub sct}), absorption efficiency (Q{sub abs}), and the scatter anisotropy (g). Calculations of these parameters are made using the analytic method of Mie theory, for spherical grains of radii 0.1-5.0 {mu}m. The sensitivity of the transport parameters to emission wavelength is investigated using an emission spectrum representative of that of Gd{sub 2}O{sub 2}S:Tb. The impact of a grain-size distribution in the screen on the parameters is investigated using a Gaussian size-distribution ({sigma}= 1%, 5%, or 10% of mean radius). Two simple and novel alternative models to Mie theory are suggested: a geometrical optics and diffraction model (GODM) and an extension of this (GODM+). Comparisons to measured MTF are made for two commercial screens: Lanex Fast Back and Lanex Fast Front (Eastman Kodak Company, Inc.). Results: The Mie theory predictions of transport parameters were shown to be highly sensitive to both grain size
Photon-Photon Collisions -- Past and Future
International Nuclear Information System (INIS)
Brodsky, Stanley J.
2005-01-01
I give a brief review of the history of photon-photon physics and a survey of its potential at future electron-positron colliders. Exclusive hadron production processes in photon-photon and electron-photon collisions provide important tests of QCD at the amplitude level, particularly as measures of hadron distribution amplitudes. There are also important high energy γγ and eγ tests of quantum chromodynamics, including the production of jets in photon-photon collisions, deeply virtual Compton scattering on a photon target, and leading-twist single-spin asymmetries for a photon polarized normal to a production plane. Since photons couple directly to all fundamental fields carrying the electromagnetic current including leptons, quarks, W's and supersymmetric particles, high energy γγ collisions will provide a comprehensive laboratory for Higgs production and exploring virtually every aspect of the Standard Model and its extensions. High energy back-scattered laser beams will thus greatly extend the range of physics of the International Linear Collider
Design and construction of a high-energy photon polarimeter
Dugger, M.; Ritchie, B. G.; Sparks, N.; Moriya, K.; Tucker, R. J.; Lee, R. J.; Thorpe, B. N.; Hodges, T.; Barbosa, F. J.; Sandoval, N.; Jones, R. T.
2017-09-01
We report on the design and construction of a high-energy photon polarimeter for measuring the degree of polarization of a linearly-polarized photon beam. The photon polarimeter uses the process of pair production on an atomic electron (triplet production). The azimuthal distribution of scattered atomic electrons following triplet production yields information regarding the degree of linear polarization of the incident photon beam. The polarimeter, operated in conjunction with a pair spectrometer, uses a silicon strip detector to measure the recoil electron distribution resulting from triplet photoproduction in a beryllium target foil. The analyzing power ΣA for the device using a 75 μm beryllium converter foil is about 0.2, with a relative systematic uncertainty in ΣA of 1.5%.
Energy Technology Data Exchange (ETDEWEB)
Behnke, Olaf; Diehl, Markus; Schoerner-Sadenius, Thomas; Steinbrueck, Georg [eds.
2010-01-15
The following topics were dealt with: Electroweak and new physics, photon-collider technology, low-energy photon experiments, prompt photons, photon structure, jets and heavy flavours, vacuum polarization and light-by-light scattering, small-x processes, diffraction, total cross sections, exclusive channels and resonances, photons in astroparticle physics. (HSI)
International Nuclear Information System (INIS)
Behnke, Olaf; Diehl, Markus; Schoerner-Sadenius, Thomas; Steinbrueck, Georg
2010-01-01
The following topics were dealt with: Electroweak and new physics, photon-collider technology, low-energy photon experiments, prompt photons, photon structure, jets and heavy flavours, vacuum polarization and light-by-light scattering, small-x processes, diffraction, total cross sections, exclusive channels and resonances, photons in astroparticle physics. (HSI)
International Nuclear Information System (INIS)
Fujii, H.
1977-01-01
High energy photon-proton scattering is expected to bring an important information on strong and electromagnetic interaction, and is discussed in this paper. When the ''mass'' of the photon is less than that of the lightest hadron, it is said ''the photon is almost real''. The photon energy is sufficiently high to check the energy dependence of the gamma-proton total cross section, even in the first stage of TRISTAN. The tagging system consists of four multi-wire proportional chambers (MWPC) and a lead glass Cerenkov counter. The energy of scattered electrons is determined with the Cerenkov counter. The equivalent-photon approximation is a useful method to obtain the counting rates. The estimation of the counting rate was made under the expected value of the total cross section. The estimated counting rate is strong enough for the experiment of the gamma-proton total cross section measurement. (Kato, T.)
Recent developments in the theory of photon-photon collisions
International Nuclear Information System (INIS)
Brodsky, S.J.
1984-09-01
Over the past few years the field of photon-photon collisions has emerged as one of the best testing grounds for QCD, particularly in the area of exclusive and inclusive hard scattering processes, exotic resonance production, and detailed tests of the coupling of real and virtual photons to the quark current. In this summary of contributed papers, I will briefly review recent theoretical progress in the analysis of two-photon reactions and possible directions for future work. 29 references
Single photon emission tomography
International Nuclear Information System (INIS)
Buvat, Irene
2011-09-01
The objective of this lecture is to present the single photon emission computed tomography (SPECT) imaging technique. Content: 1 - Introduction: anatomic, functional and molecular imaging; Principle and role of functional or molecular imaging; 2 - Radiotracers: chemical and physical constraints, main emitters, radioisotopes production, emitters type and imaging techniques; 3 - Single photon emission computed tomography: gamma cameras and their components, gamma camera specifications, planar single photon imaging characteristics, gamma camera and tomography; 4 - Quantification in single photon emission tomography: attenuation, scattering, un-stationary spatial resolution, partial volume effect, movements, others; 5 - Synthesis and conclusion
International Nuclear Information System (INIS)
Matney, Jason; Park, Peter C.; Bluett, Jaques; Chen, Yi Pei; Liu, Wei; Court, Laurence E.; Liao, Zhongxing; Li, Heng; Mohan, Radhe
2013-01-01
Purpose: To quantify and compare the effects of respiratory motion on paired passively scattered proton therapy (PSPT) and intensity modulated photon therapy (IMRT) plans; and to establish the relationship between the magnitude of tumor motion and the respiratory-induced dose difference for both modalities. Methods and Materials: In a randomized clinical trial comparing PSPT and IMRT, radiation therapy plans have been designed according to common planning protocols. Four-dimensional (4D) dose was computed for PSPT and IMRT plans for a patient cohort with respiratory motion ranging from 3 to 17 mm. Image registration and dose accumulation were performed using grayscale-based deformable image registration algorithms. The dose–volume histogram (DVH) differences (4D-3D [3D = 3-dimensional]) were compared for PSPT and IMRT. Changes in 4D-3D dose were correlated to the magnitude of tumor respiratory motion. Results: The average 4D-3D dose to 95% of the internal target volume was close to zero, with 19 of 20 patients within 1% of prescribed dose for both modalities. The mean 4D-3D between the 2 modalities was not statistically significant (P<.05) for all dose–volume histogram indices (mean ± SD) except the lung V5 (PSPT: +1.1% ± 0.9%; IMRT: +0.4% ± 1.2%) and maximum cord dose (PSPT: +1.5 ± 2.9 Gy; IMRT: 0.0 ± 0.2 Gy). Changes in 4D-3D dose were correlated to tumor motion for only 2 indices: dose to 95% planning target volume, and heterogeneity index. Conclusions: With our current margin formalisms, target coverage was maintained in the presence of respiratory motion up to 17 mm for both PSPT and IMRT. Only 2 of 11 4D-3D indices (lung V5 and spinal cord maximum) were statistically distinguishable between PSPT and IMRT, contrary to the notion that proton therapy will be more susceptible to respiratory motion. Because of the lack of strong correlations with 4D-3D dose differences in PSPT and IMRT, the extent of tumor motion was not an adequate predictor of potential
Energy Technology Data Exchange (ETDEWEB)
Matney, Jason; Park, Peter C. [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); The University of Texas Graduate School of Biomedical Sciences, Houston, Texas (United States); Bluett, Jaques [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Chen, Yi Pei [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); The University of Texas Graduate School of Biomedical Sciences, Houston, Texas (United States); Liu, Wei; Court, Laurence E. [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Liao, Zhongxing [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Li, Heng [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Mohan, Radhe, E-mail: rmohan@mdanderson.org [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)
2013-11-01
Purpose: To quantify and compare the effects of respiratory motion on paired passively scattered proton therapy (PSPT) and intensity modulated photon therapy (IMRT) plans; and to establish the relationship between the magnitude of tumor motion and the respiratory-induced dose difference for both modalities. Methods and Materials: In a randomized clinical trial comparing PSPT and IMRT, radiation therapy plans have been designed according to common planning protocols. Four-dimensional (4D) dose was computed for PSPT and IMRT plans for a patient cohort with respiratory motion ranging from 3 to 17 mm. Image registration and dose accumulation were performed using grayscale-based deformable image registration algorithms. The dose–volume histogram (DVH) differences (4D-3D [3D = 3-dimensional]) were compared for PSPT and IMRT. Changes in 4D-3D dose were correlated to the magnitude of tumor respiratory motion. Results: The average 4D-3D dose to 95% of the internal target volume was close to zero, with 19 of 20 patients within 1% of prescribed dose for both modalities. The mean 4D-3D between the 2 modalities was not statistically significant (P<.05) for all dose–volume histogram indices (mean ± SD) except the lung V5 (PSPT: +1.1% ± 0.9%; IMRT: +0.4% ± 1.2%) and maximum cord dose (PSPT: +1.5 ± 2.9 Gy; IMRT: 0.0 ± 0.2 Gy). Changes in 4D-3D dose were correlated to tumor motion for only 2 indices: dose to 95% planning target volume, and heterogeneity index. Conclusions: With our current margin formalisms, target coverage was maintained in the presence of respiratory motion up to 17 mm for both PSPT and IMRT. Only 2 of 11 4D-3D indices (lung V5 and spinal cord maximum) were statistically distinguishable between PSPT and IMRT, contrary to the notion that proton therapy will be more susceptible to respiratory motion. Because of the lack of strong correlations with 4D-3D dose differences in PSPT and IMRT, the extent of tumor motion was not an adequate predictor of potential
International Nuclear Information System (INIS)
Gilman, F.J.
1980-01-01
A brief summary of the present status of photon-photon interactions is presented. Stress is placed on the use of two-photon collisions to test present ideas on the quark constituents of hadrons and on the theory of strong interactions
International Nuclear Information System (INIS)
Botto, D.J.; Pratt, R.H.
1979-05-01
The current status of Compton scattering, both experimental observations and the theoretical predictions, is examined. Classes of experiments are distinguished and the results obtained are summarized. The validity of the incoherent scattering function approximation and the impulse approximation is discussed. These simple theoretical approaches are compared with predictions of the nonrelativistic dipole formula of Gavrila and with the relativistic results of Whittingham. It is noted that the A -2 based approximations fail to predict resonances and an infrared divergence, both of which have been observed. It appears that at present the various available theoretical approaches differ significantly in their predictions and that further and more systematic work is required
Energy Technology Data Exchange (ETDEWEB)
Botto, D.J.; Pratt, R.H.
1979-05-01
The current status of Compton scattering, both experimental observations and the theoretical predictions, is examined. Classes of experiments are distinguished and the results obtained are summarized. The validity of the incoherent scattering function approximation and the impulse approximation is discussed. These simple theoretical approaches are compared with predictions of the nonrelativistic dipole formula of Gavrila and with the relativistic results of Whittingham. It is noted that the A/sup -2/ based approximations fail to predict resonances and an infrared divergence, both of which have been observed. It appears that at present the various available theoretical approaches differ significantly in their predictions and that further and more systematic work is required.
International Nuclear Information System (INIS)
Bardin, D.Yu.
1979-01-01
Basing on the simple quark-parton model of strong interaction and on the Weinberg-Salam theory compact formulae are derived for the radiative correction to the charged current induced deep inelastic scattering of neutrinos on nucleons. The radiative correction is found to be around 20-30%, i.e., the value typical for deep inelastic lN-scattering. The results obtained are rather different from the presently available estimations of the effect under consideration
Study of direct photons produced in hadronic interactions
International Nuclear Information System (INIS)
Karyotakis, Y.
1985-05-01
This thesis studies direct photons produced by π + , π - and proton beams of 200 GeV/c, momentum interacting with a carbon target. QCD predicts that direct photons are produced either by the quark-antiquark annihilation qantiq → gγ, or by gluon scattering gq → qγ. The experiment was performed at CERN and used the NA3 spectrometer. Photons are converted within 10% conversion length, and resulting e + e - are detected by the trigger system which requires a minimum transverse momentum of 2.5 GeV/c. Electrons tracks are detected by the spectrometer, while energy and position of photons are measured by an electromagnetic calorimeter and a shower chamber. Direct photon's signal is obtained only statistically, after correcting the ''single photons'' candidats for the π 0 and eta 0 contribution. This correction is obtained only from a sophisticated Monte Carlo, in which electromagnetic shower simulation is difficult. We have observed a significant direct photon signal and we measured the cross section. The γ/π 0 ratio at psub(t) = 4.5 GeV/c is about 10% and seems to grow as a function of transverse momentum. Systematic errors, which are important, limit the precision on the gluon's structure function measurement [fr
International Nuclear Information System (INIS)
Sessler, A.M.
1995-04-01
Since the seminal work by Ginsburg, et at., the subject of giving the Next Linear Collider photon-photon capability, as well as electron-positron capability, has drawn much attention. A 1990 article by V.I. Teinov describes the situation at that time. In March 1994, the first workshop on this subject was held. This report briefly reviews the physics that can be achieved through the photon-photon channel and then focuses on the means of achieving such a collider. Also reviewed is the spectrum of backscattered Compton photons -- the best way of obtaining photons. We emphasize the spectrum actually obtained in a collider with both polarized electrons and photons (peaked at high energy and very different from a Compton spectrum). Luminosity is estimated for the presently considered colliders, and interaction and conversion-point geometries are described. Also specified are laser requirements (such as wavelength, peak power, and average power) and the lasers that might be employed. These include conventional and free-electron lasers. Finally, we describe the R ampersand D necessary to make either of these approaches viable and explore the use of the SLC as a test bed for a photon-photon collider of very high energy
High-intensity-laser-electron scattering
International Nuclear Information System (INIS)
Meyerhofer, D.D.
1997-01-01
In the field of an intense laser, photon-electron scattering becomes nonlinear when the oscillatory energy of the electron approaches its rest mass. The electron wave function is dressed by the field with a concomitant increase in the effective electron mass. When the photon energy in the electron rest frame is comparable to the electron rest mass, multiphoton Compton scattering occurs. When the photon energy is significantly lower than the electron rest mass, the electron acquires momentum from the photon field and emits harmonics. This paper reviews nonlinear photon-electron scattering processes and results from two recent experiments where they have been observed
Skrobala, A; Adamczyk, S; Kruszyna-Mochalska, M; Skórska, M; Konefał, A; Suchorska, W; Zaleska, K; Kowalik, A; Jackowiak, W; Malicki, J
2017-08-01
During radiotherapy, leakage from the machine head and collimator expose patients to out-of-field irradiation doses, which may cause secondary cancers. To quantify the risks of secondary cancers due to out-of-field doses, it is first necessary to measure these doses. Since most dosimeters are energy-dependent, it is essential to first determine the type of photon energy spectrum in the out-of-field area. The aim of this study was to determine the mean photon energy values for the out-of-field photon energy spectrum for a 6 MV photon beam using the GEANT 4-Monte Carlo method. A specially-designed large water phantom was simulated with a static field at gantry 0°. The source-to-surface distance was 92cm for an open field size of 10×10cm2. The photon energy spectra were calculated at five unique positions (at depths of 0.5, 1.6, 4, 6, 8, and 10cm) along the central beam axis and at six different off-axis distances. Monte Carlo simulations showed that mean radiation energy levels drop rapidly beyond the edge of the 6 MV photon beam field: at a distance of 10cm, the mean energy level is close to 0.3MeV versus 1.5MeV at the central beam axis. In some cases, the energy level actually increased even as the distance from the field edge increased: at a depth of 1.6cm and 15cm off-axis, the mean energy level was 0.205MeV versus 0.252MeV at 20cm off-axis. The out-of-field energy spectra and dose distribution data obtained in this study with Monte Carlo methods can be used to calibrate dosimeters to measure out-of-field radiation from 6MV photons. Copyright © 2017 Société française de radiothérapie oncologique (SFRO). Published by Elsevier SAS. All rights reserved.
Very energetic photons at HERA
International Nuclear Information System (INIS)
Bawa, A.C.; Krawczyk, M.
1991-01-01
We show that every energetic photons in the backward direction can be produced in deep inelastic Compton scattering at HERA. Assuming a fixed energy of 9 GeV for the initial photons and 820 GeV for the protons a high rate is found for the production of final photons with a transverse momentum equal to 5 GeV/c and energy between 40 GeV and 300 GeV. These energetic photons arise mainly from the scattering of the soft gluonic constituents of the initial photon with quarks from the proton. They are produced in the backward direction in coincidence with a photon beam jet of energy ∝ 9 GeV in the forward direction. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Wuosmaa, A.H.; Wiedenhoever, I.; Caggiano, J.; Carpenter, M.P.; Devlin, M.; Heinz, A.; Janssens, R.V.F.; Kondev, F.; Lauritsen, T.; Sarantites, D.G.; Sobotka, L.G.; Battacharyya, P
2003-10-09
Particle gamma-ray angular correlation measurements have been used to study the spin alignment and magnetic-substate population parameters for the 2{sup +}{sub 1} (4.443 MeV) state in {sup 12}C, populated in the {sup 12}C({sup 12}C,{sup 12}C[0{sup +}{sub 2}]){sup 12}C(2{sup +}{sub 1}) inelastic scattering reaction in the vicinity of a prominent, narrow peak in the scattering excitation function. The data show a strong alignment of the spin with the orbital angular momentum, and suggest that the cross section peak corresponds to a spin 14{sup +} resonance at E{sub c.m.}=28.0 MeV. This energy is close to that where a strong peak is also observed in the 0{sup +}{sub 1}+0{sup +}{sub 2} excitation function. A comparison between the data for these two channels lends some support to recent theoretical calculations of resonance behavior for angular-momentum-mismatched channels in {sup 12}C+{sup 12}C inelastic scattering.
XCOM: Photon Cross Sections Database
SRD 8 XCOM: Photon Cross Sections Database (Web, free access) A web database is provided which can be used to calculate photon cross sections for scattering, photoelectric absorption and pair production, as well as total attenuation coefficients, for any element, compound or mixture (Z <= 100) at energies from 1 keV to 100 GeV.
Energy Technology Data Exchange (ETDEWEB)
LI, Ming [Iowa State Univ., Ames, IA (United States)
2007-01-01
In this dissertation, a set of numerical simulation tools are developed under previous work to efficiently and accurately study one-dimensional (1D), two-dimensional(2D), 2D slab and three-dimensional (3D) photonic crystal structures and their defects effects by means of spectrum (transmission, reflection, absorption), band structure (dispersion relation), and electric and/or magnetic fields distribution (mode profiles). Furthermore, the lasing property and spontaneous emission behaviors are studied when active gain materials are presented in the photonic crystal structures. Various physical properties such as resonant cavity quality factor, waveguide loss, propagation group velocity of electromagnetic wave and light-current curve (for lasing devices) can be obtained from the developed software package.
Varghese, Babu; Rajan, Vinayakrishnan; van Leeuwen, Ton G.; Steenbergen, Wiendelt
2007-01-01
In optical Doppler measurements, the path length of the light is unknown. To facilitate quantitative measurements, we develop a phase-modulated Mach-Zehnder interferometer with separate fibers for illumination and detection. With this setup, path-length-resolved dynamic light scattering measurements
Electron scattering for exotic nuclei
Indian Academy of Sciences (India)
2014-11-04
Nov 4, 2014 ... Research Center for Electron-Photon Science, Tohoku University, 1-2-1 ... nuclei precisely determined by elastic scattering [1]. .... In order to fulfill these requirements, a window-frame shaped dipole magnet with a gap.
Qattan, I. A.; Homouz, D.; Riahi, M. K.
2018-04-01
In this work, we improve on and extend to low- and high-Q2 values the extractions of the two-photon-exchange (TPE) amplitudes and the ratio Pl/PlBorn(ɛ ,Q2) using world data on electron-proton elastic scattering cross section σR(ɛ ,Q2) with an emphasis on data covering the high-momentum region, up to Q2=5.20 (GeV/c ) 2 , to better constrain the TPE amplitudes in this region. We provide a new parametrization of the TPE amplitudes, along with an estimate of the fit uncertainties. We compare the results to several previous phenomenological extractions and hadronic TPE predictions. We use the new parametrization of the TPE amplitudes to extract the ratio Pl/PlBorn(ɛ ,Q2) , and then compare the results to previous extractions, several theoretical calculations, and direct measurements at Q2=2.50 (GeV/c ) 2 .
Sarma, Manabendra; Adhikari, S; Mishra, Manoj K
2007-01-28
Vibrational excitation (nu(f), where psi(nu(i))(R,t) approximately =e(-iH(A(2))-(R)t/h phi(nu(i))(R) with time evolution under the influence of the resonance anionic Hamiltonian H(A(2) (-))(A(2) (-)=N(2)(-)/H(2) (-)) implemented using Lanczos and fast Fourier transforms. The target (A(2)) vibrational eigenfunctions phi(nu(i))(R) and phi(nu(f))(R) are calculated using Fourier grid Hamiltonian method applied to potential energy (PE) curves of the neutral target. Application of this simple systematization to calculate vibrational structure in e-N(2) and e-H(2) scattering cross-sections provides mechanistic insights into features underlying presence/absence of structure in e-N(2) and e-H(2) scattering cross-sections. The results obtained with approximate PE curves are in reasonable agreement with experimental/calculated cross-section profiles, and cross correlation functions provide a simple demarcation between the boomerang and impulse models.
Optics of globular photonic crystals
International Nuclear Information System (INIS)
Gorelik, V S
2007-01-01
The results of experimental and theoretical studies of the optical properties of globular photonic crystals - new physical objects having a crystal structure with the lattice period exceeding considerably the atomic size, are presented. As globular photonic crystals, artificial opal matrices consisting of close-packed silica globules of diameter ∼200 nm were used. The reflection spectra of these objects characterising the parameters of photonic bands existing in these crystals in the visible spectral region are presented. The idealised models of the energy band structure of photonic crystals investigated in the review give analytic dispersion dependences for the group velocity and the effective photon mass in a globular photonic crystal. The characteristics of secondary emission excited in globular photonic crystals by monochromatic and broadband radiation are presented. The results of investigations of single-photon-excited delayed scattering of light observed in globular photonic crystals exposed to cw UV radiation and radiation from a repetitively pulsed copper vapour laser are presented. The possibilities of using globular photonic crystals as active media for lasing in different spectral regions are considered. It is proposed to use globular photonic crystals as sensitive sensors in optoelectronic devices for molecular analysis of organic and inorganic materials by the modern methods of laser spectroscopy. The results of experimental studies of spontaneous and stimulated globular scattering of light are discussed. The conditions for observing resonance and two-photon-excited delayed scattering of light are found. The possibility of accumulation and localisation of the laser radiation energy inside a globular photonic crystal is reported. (review)
International Nuclear Information System (INIS)
Bardeen, W.A.
1980-11-01
Theoretical understanding of the photon structure function is reviewed. As an illustration of the pointlike component, the parton model is briefly discussed. However, the systematic study of the photon structure function is presented through the framework of the operator product expansion. Perturbative QCD is used as the theoretical basis for the calculation of leading contributions to the operator product expansion. The influence of higher order QCD effects on these results is discussed. Recent results for the polarized structure functions are discussed
Energy Technology Data Exchange (ETDEWEB)
Brodsky, S.J.
1985-01-01
The study of photon-photon collisions has progressed enormously, stimulated by new data and new calculational tools for QCD. In the future we can expect precise determinations of ..cap alpha../sub s/ and ..lambda../sup ms/ from the ..gamma..*..gamma.. ..-->.. ..pi../sup 0/ form factor and the photon structure function, as well as detailed checks of QCD, determination of the shape of the hadron distribution amplitudes from ..gamma gamma.. ..-->.. H anti H, reconstruction of sigma/sub ..gamma gamma../ from exclusive channels at low W/sub ..gamma gamma../, definitive studies of high p/sub T/ hadron and jet production, and studies of threshold production of charmed systems. Photon-photon collisions, along with radiative decays of the psi and UPSILON, are ideal for the study of multiquark and gluonic resonances. We have emphasized the potential for resonance formation near threshold in virtually every hadronic exclusive channel, including heavy quark states c anti c c anti c, c anti c u anti u, etc. At higher energies SLC, LEP, ...) parity-violating electroweak effects and Higgs production due to equivalent Z/sup 0/ and W/sup + -/ beams from e ..-->.. eZ/sup 0/ and e ..-->.. nu W will become important. 44 references.
International Nuclear Information System (INIS)
Brodsky, S.J.
1985-01-01
The study of photon-photon collisions has progressed enormously, stimulated by new data and new calculational tools for QCD. In the future we can expect precise determinations of α/sub s/ and Λ/sup ms/ from the γ*γ → π 0 form factor and the photon structure function, as well as detailed checks of QCD, determination of the shape of the hadron distribution amplitudes from γγ → H anti H, reconstruction of sigma/sub γγ/ from exclusive channels at low W/sub γγ/, definitive studies of high p/sub T/ hadron and jet production, and studies of threshold production of charmed systems. Photon-photon collisions, along with radiative decays of the psi and UPSILON, are ideal for the study of multiquark and gluonic resonances. We have emphasized the potential for resonance formation near threshold in virtually every hadronic exclusive channel, including heavy quark states c anti c c anti c, c anti c u anti u, etc. At higher energies SLC, LEP, ...) parity-violating electroweak effects and Higgs production due to equivalent Z 0 and W +- beams from e → eZ 0 and e → nu W will become important. 44 references
International Nuclear Information System (INIS)
Field, J.H.
1984-01-01
The current status, both theoretical and experimental, of two photon collision physics is reviewed with special emphasis on recent experimental results from e + e - storage rings. After a complete presentation of the helicity amplitude formalism for the general process e + e - → Xe + e - , various approximations (transverse photon, Weisaecker Williams) are discussed. Beam polarisation effects and radiative corrections are also briefly considered. A number of specific processes, for which experimental results are now available, are then described. In each case existing theoretical prediction are confronted with experimental results. The processes described include single resonance production, lepton and hadron pair production, the structure functions of the photon, the production of high Psub(T) jets and the total photon photon cross section. In the last part of the review the current status of the subject is summarised and some comments are made on future prospects. These include both extrapolations of current research to higher energy machines (LEP, HERA) as well as a brief mention of both the technical realisation and the physics interest of the real γγ and eγ collisions which may be possible using linear electron colliders in the 1 TeV energy range
Leyland, M J; Beurskens, M N A; Flanagan, J C; Frassinetti, L; Gibson, K J; Kempenaars, M; Maslov, M; Scannell, R
2016-01-01
The Joint European Torus (JET) high resolution Thomson scattering (HRTS) system measures radial electron temperature and density profiles. One of the key capabilities of this diagnostic is measuring the steep pressure gradient, termed the pedestal, at the edge of JET plasmas. The pedestal is susceptible to limiting instabilities, such as Edge Localised Modes (ELMs), characterised by a periodic collapse of the steep gradient region. A common method to extract the pedestal width, gradient, and height, used on numerous machines, is by performing a modified hyperbolic tangent (mtanh) fit to overlaid profiles selected from the same region of the ELM cycle. This process of overlaying profiles, termed ELM synchronisation, maximises the number of data points defining the pedestal region for a given phase of the ELM cycle. When fitting to HRTS profiles, it is necessary to incorporate the diagnostic radial instrument function, particularly important when considering the pedestal width. A deconvolved fit is determined by a forward convolution method requiring knowledge of only the instrument function and profiles. The systematic error due to the deconvolution technique incorporated into the JET pedestal fitting tool has been documented by Frassinetti et al. [Rev. Sci. Instrum. 83, 013506 (2012)]. This paper seeks to understand and quantify the systematic error introduced to the pedestal width due to ELM synchronisation. Synthetic profiles, generated with error bars and point-to-point variation characteristic of real HRTS profiles, are used to evaluate the deviation from the underlying pedestal width. We find on JET that the ELM synchronisation systematic error is negligible in comparison to the statistical error when assuming ten overlaid profiles (typical for a pre-ELM fit to HRTS profiles). This confirms that fitting a mtanh to ELM synchronised profiles is a robust and practical technique for extracting the pedestal structure.
REVIEW: Optics of globular photonic crystals
Gorelik, V. S.
2007-05-01
The results of experimental and theoretical studies of the optical properties of globular photonic crystals - new physical objects having a crystal structure with the lattice period exceeding considerably the atomic size, are presented. As globular photonic crystals, artificial opal matrices consisting of close-packed silica globules of diameter ~200 nm were used. The reflection spectra of these objects characterising the parameters of photonic bands existing in these crystals in the visible spectral region are presented. The idealised models of the energy band structure of photonic crystals investigated in the review give analytic dispersion dependences for the group velocity and the effective photon mass in a globular photonic crystal. The characteristics of secondary emission excited in globular photonic crystals by monochromatic and broadband radiation are presented. The results of investigations of single-photon-excited delayed scattering of light observed in globular photonic crystals exposed to cw UV radiation and radiation from a repetitively pulsed copper vapour laser are presented. The possibilities of using globular photonic crystals as active media for lasing in different spectral regions are considered. It is proposed to use globular photonic crystals as sensitive sensors in optoelectronic devices for molecular analysis of organic and inorganic materials by the modern methods of laser spectroscopy. The results of experimental studies of spontaneous and stimulated globular scattering of light are discussed. The conditions for observing resonance and two-photon-excited delayed scattering of light are found. The possibility of accumulation and localisation of the laser radiation energy inside a globular photonic crystal is reported.
Radiative kaon capture on deuterium and the Λn scattering lengths
International Nuclear Information System (INIS)
Gall, K.P.; Booth, E.C.; Fickinger, W.J.; Hasinoff, M.D.; Hessey, N.P.; Horvath, D.; Lowe, J.; McIntyre, E.K.; Measday, D.F.; Miller, J.P.; Noble, A.J.; Roberts, B.L.; Robinson, D.K.; Sakitt, M.; Salomon, M.; Whitehouse, D.A.
1990-01-01
The photon spectrum from K - d→Λnγ at rest has been measured for the first time. We obtained the branching ratio, in the end-point region, of (1.89±0.12±0.28)x10 -3 where the first error is statistical and the second is systematic. We have found that the shape of the photon energy spectrum is consistent with the distribution calculated by Workman and Fearing with Λn scattering lengths and effective ranges predicted by the Nijmegen group
Photon Entanglement Through Brain Tissue.
Shi, Lingyan; Galvez, Enrique J; Alfano, Robert R
2016-12-20
Photon entanglement, the cornerstone of quantum correlations, provides a level of coherence that is not present in classical correlations. Harnessing it by study of its passage through organic matter may offer new possibilities for medical diagnosis technique. In this work, we study the preservation of photon entanglement in polarization, created by spontaneous parametric down-conversion, after one entangled photon propagates through multiphoton-scattering brain tissue slices with different thickness. The Tangle-Entropy (TS) plots show the strong preservation of entanglement of photons propagating in brain tissue. By spatially filtering the ballistic scattering of an entangled photon, we find that its polarization entanglement is preserved and non-locally correlated with its twin in the TS plots. The degree of entanglement correlates better with structure and water content than with sample thickness.
Energy Technology Data Exchange (ETDEWEB)
Meyer, Arne [University of Hamburg, c/o DESY, Building 22a, Notkestrasse 85, 22603 Hamburg (Germany); Dierks, Karsten [University of Hamburg, c/o DESY, Building 22a, Notkestrasse 85, 22603 Hamburg (Germany); XtalConcepts, Marlowring 19, 22525 Hamburg (Germany); Hussein, Rana [University of Hamburg, c/o DESY, Building 22a, Notkestrasse 85, 22603 Hamburg (Germany); Brillet, Karl [ESBS, Pôle API, 300 Boulevard Sébastien Brant, CS10413, 67412 Illkirch CEDEX (France); Brognaro, Hevila [São Paulo State University, UNESP/IBILCE, Caixa Postal 136, São José do Rio Preto-SP, 15054 (Brazil); Betzel, Christian, E-mail: christian.betzel@uni-hamburg.de [University of Hamburg, c/o DESY, Building 22a, Notkestrasse 85, 22603 Hamburg (Germany)
2015-01-01
Application of in situ dynamic light scattering to solutions of protein–detergent complexes permits characterization of these complexes in samples as small as 2 µl in volume. Detergents are widely used for the isolation and solubilization of membrane proteins to support crystallization and structure determination. Detergents are amphiphilic molecules that form micelles once the characteristic critical micelle concentration (CMC) is achieved and can solubilize membrane proteins by the formation of micelles around them. The results are presented of a study of micelle formation observed by in situ dynamic light-scattering (DLS) analyses performed on selected detergent solutions using a newly designed advanced hardware device. DLS was initially applied in situ to detergent samples with a total volume of approximately 2 µl. When measured with DLS, pure detergents show a monodisperse radial distribution in water at concentrations exceeding the CMC. A series of all-transn-alkyl-β-d-maltopyranosides, from n-hexyl to n-tetradecyl, were used in the investigations. The results obtained verify that the application of DLS in situ is capable of distinguishing differences in the hydrodynamic radii of micelles formed by detergents differing in length by only a single CH{sub 2} group in their aliphatic tails. Subsequently, DLS was applied to investigate the distribution of hydrodynamic radii of membrane proteins and selected water-insoluble proteins in presence of detergent micelles. The results confirm that stable protein–detergent complexes were prepared for (i) bacteriorhodopsin and (ii) FetA in complex with a ligand as examples of transmembrane proteins. A fusion of maltose-binding protein and the Duck hepatitis B virus X protein was added to this investigation as an example of a non-membrane-associated protein with low water solubility. The increased solubility of this protein in the presence of detergent could be monitored, as well as the progress of proteolytic
Scattering and absorption differential cross sections for double ...
Indian Academy of Sciences (India)
The scattering and absorption differential cross sections for nonlinear QED process such as double photon Compton scattering have been measured as a function of independent ﬁnal photon energy. The incident gamma photons are of 0.662 MeV in energy as produced by an 8 Ci137Cs radioactive source and thin ...
Attenuation and scatter correction in SPECT
International Nuclear Information System (INIS)
Pant, G.S.; Pandey, A.K.
2000-01-01
While passing through matter, photons undergo various types of interactions. In the process, some photons are completely absorbed, some are scattered in different directions with or without any change in their energy and some pass through unattenuated. These unattenuated photons carry the information with them. However, the image data gets corrupted with attenuation and scatter processes. This paper deals with the effect of these two processes in nuclear medicine images and suggests the methods to overcome them
Electron scattering from sodium at intermediate energies
International Nuclear Information System (INIS)
Mitroy, J.; McCarthy, I.E.
1986-10-01
A comprehensive comparison is made between theoretical calculations and experimental data for intermediate energy (≥ 10 eV) electron scattering from sodium vapour. The theoretical predictions of coupled-channels calculations (including one, two or four channels) do not agree with experimental values of the differential cross sections for elastic scattering or the resonant 3s to 3p excitation. Increasingly-more-sophisticated calculations, incorporating electron correlations in the target states, and also including core-excited states in the close-coupling expansion, are done at a few selected energies in an attempt to isolate the cause of the discrepancies between theory and experiment. It is found that these more-sophisticated calculations give essentially the same results as the two- and four-channel calculations using Hartree-Fock wavefunctions. Comparison of the sodium high-energy elastic differential cross sections with those of neon suggests that the sodium differential cross section experiments may suffer from systematic errors. There is also disagreement, at the higher energies, between theoretical values for the scattering parameters and those that are derived from laser-excited superelastic scattering and electron photon coincidence experiments. When allowance is made for the finite acceptance angle of the electron spectrometers used in the experiments by convoluting the theory with a function representing the distribution of electrons entering the electron spectrometer it is found that the magnitudes of the differences between theory and experiment are reduced
Reconfigurable topological photonic crystal
Shalaev, Mikhail I.; Desnavi, Sameerah; Walasik, Wiktor; Litchinitser, Natalia M.
2018-02-01
Topological insulators are materials that conduct on the surface and insulate in their interior due to non-trivial topology of the band structure. The edge states on the interface between topological (non-trivial) and conventional (trivial) insulators are topologically protected from scattering due to structural defects and disorders. Recently, it was shown that photonic crystals (PCs) can serve as a platform for realizing a scatter-free propagation of light waves. In conventional PCs, imperfections, structural disorders, and surface roughness lead to significant losses. The breakthrough in overcoming these problems is likely to come from the synergy of the topological PCs and silicon-based photonics technology that enables high integration density, lossless propagation, and immunity to fabrication imperfections. For many applications, reconfigurability and capability to control the propagation of these non-trivial photonic edge states is essential. One way to facilitate such dynamic control is to use liquid crystals (LCs), which allow to modify the refractive index with external electric field. Here, we demonstrate dynamic control of topological edge states by modifying the refractive index of a LC background medium. Background index is changed depending on the orientation of a LC, while preserving the topology of the system. This results in a change of the spectral position of the photonic bandgap and the topological edge states. The proposed concept might be implemented using conventional semiconductor technology, and can be used for robust energy transport in integrated photonic devices, all-optical circuity, and optical communication systems.
Quantum Optical Multiple Scattering
DEFF Research Database (Denmark)
Ott, Johan Raunkjær
. In the first part we use a scattering-matrix formalism combined with results from random-matrix theory to investigate the interference of quantum optical states on a multiple scattering medium. We investigate a single realization of a scattering medium thereby showing that it is possible to create entangled...... states by interference of squeezed beams. Mixing photon states on the single realization also shows that quantum interference naturally arises by interfering quantum states. We further investigate the ensemble averaged transmission properties of the quantized light and see that the induced quantum...... interference survives even after disorder averaging. The quantum interference manifests itself through increased photon correlations. Furthermore, the theoretical description of a measurement procedure is presented. In this work we relate the noise power spectrum of the total transmitted or reflected light...
Prompt photon measurements with the PHENIX MPC-EX detector
Campbell, Sarah
2013-04-01
The MPC-EX detector is a preshower extension to PHENIX's Muon Piston Calorimeter (MPC). It consists of eight layers of alternating W absorber and Si mini-pad sensors. Located at forward rapidity, 3.180 GeV, allowing the measurement of prompt photons using the double ratio method. At forward rapidities, prompt photons are dominated by direct photons produced by quark-gluon Compton scattering. In transversely polarized p+p collisions, the prompt photon single spin asymmetry measurement, AN, will resolve the sign discrepancy between the Sivers and twist-3 extractions of AN. In p+Au collisions, the prompt photon RpAu will quantify the level of gluon saturation in the Au nucleus at low-x, 10-3, with a projected systematic error band a factor of four smaller than EPS09's current allowable range. The MPC-EX detector will expand our understanding of gluon nuclear parton distribution functions, providing information about the initial state of heavy ion collisions, and clarify how valence parton's pT and spin correlate to the proton spin.
CONFERENCE: Photon-photon collisions
International Nuclear Information System (INIS)
Anon.
1983-01-01
Despite being difficult to observe, photon-photon collisions have opened up a range of physics difficult, or even impossible, to access by other methods. The progress which has been made in this field was evident at the fifth international workshop on photon-photon collisions, held in Aachen from 13-16 April and attended by some 120 physicists
Photon-splitting cross sections
International Nuclear Information System (INIS)
Johannessen, A.M.; Mork, K.J.; Overbo, I.
1980-01-01
The differential cross section for photon splitting (scattering of one photon into two photons) in a Coulomb field, obtained earlier by Shima, has been integrated numerically to yield various differential cross sections. Energy spectra differential with respect to the energy of one of the outgoing photons are presented for several values of the primary photon energy. Selected examples of recoil momentum distributions and some interesting doubly or multiply differential cross sections are also given. Values for the total cross section are obtained essentially for all energies. The screening effect caused by atomic electrons is also taken into account, and is found to be important for high energies, as in e + e - pair production. Comparisons with various approximate results obtained by previous authors mostly show fair agreement. We also discuss the possibilities for experimental detection and find the most promising candidate to be a measurement of both photons, and their energies, at a moderately high energy
Scattering Correction For Image Reconstruction In Flash Radiography
International Nuclear Information System (INIS)
Cao, Liangzhi; Wang, Mengqi; Wu, Hongchun; Liu, Zhouyu; Cheng, Yuxiong; Zhang, Hongbo
2013-01-01
Scattered photons cause blurring and distortions in flash radiography, reducing the accuracy of image reconstruction significantly. The effect of the scattered photons is taken into account and an iterative deduction of the scattered photons is proposed to amend the scattering effect for image restoration. In order to deduct the scattering contribution, the flux of scattered photons is estimated as the sum of two components. The single scattered component is calculated accurately together with the uncollided flux along the characteristic ray, while the multiple scattered component is evaluated using correction coefficients pre-obtained from Monte Carlo simulations.The arbitrary geometry pretreatment and ray tracing are carried out based on the customization of AutoCAD. With the above model, an Iterative Procedure for image restORation code, IPOR, is developed. Numerical results demonstrate that the IPOR code is much more accurate than the direct reconstruction solution without scattering correction and it has a very high computational efficiency
Scattering Correction For Image Reconstruction In Flash Radiography
Energy Technology Data Exchange (ETDEWEB)
Cao, Liangzhi; Wang, Mengqi; Wu, Hongchun; Liu, Zhouyu; Cheng, Yuxiong; Zhang, Hongbo [Xi' an Jiaotong Univ., Xi' an (China)
2013-08-15
Scattered photons cause blurring and distortions in flash radiography, reducing the accuracy of image reconstruction significantly. The effect of the scattered photons is taken into account and an iterative deduction of the scattered photons is proposed to amend the scattering effect for image restoration. In order to deduct the scattering contribution, the flux of scattered photons is estimated as the sum of two components. The single scattered component is calculated accurately together with the uncollided flux along the characteristic ray, while the multiple scattered component is evaluated using correction coefficients pre-obtained from Monte Carlo simulations.The arbitrary geometry pretreatment and ray tracing are carried out based on the customization of AutoCAD. With the above model, an Iterative Procedure for image restORation code, IPOR, is developed. Numerical results demonstrate that the IPOR code is much more accurate than the direct reconstruction solution without scattering correction and it has a very high computational efficiency.
Photon technology. Hard photon technology; Photon technology. Hard photon gijutsu
Energy Technology Data Exchange (ETDEWEB)
NONE
1996-03-01
Research results of hard photon technology have been summarized as a part of novel technology development highly utilizing the quantum nature of photon. Hard photon technology refers to photon beam technologies which use photon in the 0.1 to 200 nm wavelength region. Hard photon has not been used in industry due to the lack of suitable photon sources and optical devices. However, hard photon in this wavelength region is expected to bring about innovations in such areas as ultrafine processing and material synthesis due to its atom selective reaction, inner shell excitation reaction, and spatially high resolution. Then, technological themes and possibility have been surveyed. Although there are principle proposes and their verification of individual technologies for the technologies of hard photon generation, regulation and utilization, they are still far from the practical applications. For the photon source technology, the laser diode pumped driver laser technology, laser plasma photon source technology, synchrotron radiation photon source technology, and vacuum ultraviolet photon source technology are presented. For the optical device technology, the multi-layer film technology for beam mirrors and the non-spherical lens processing technology are introduced. Also are described the reduction lithography technology, hard photon excitation process, and methods of analysis and measurement. 430 refs., 165 figs., 23 tabs.
International Nuclear Information System (INIS)
Friedrich, J.; Voegler, N.
1982-01-01
All available information on charge distributions of even-even nuclei is analysed systematically. For medium and heavy nuclei five general features of p(r) are investigated: (i) The extension for which we discuss several different definitions. The measured extension together with experimental binding energies allows a determination of nuclear compressibility within the framework of the droplet model, the resulting value being K = 165 +- 10 MeV. (ii) The surface thickness. Here too, several definitions are discussed. A close relationship between the surface thickness and binding energies is demonstrated. (iii) The average slope in the inner part of the nucleus. A method is formulated to separate this slope from the oscillations observed. All nuclei show a positive slope of comparable size. (iv) The oscillations on p(r). They are related to an abrupt breakdown in the form factor around q = 2.25 fm -1 . This effect seems to be closely related to the fact that p(r) is built up out of single particles, details however being unimportant. (v) The high-q components of the form factor are indicative for a scattering mechanism involving pairs of nucleons. (orig.)
Superradiative scattering magnons
International Nuclear Information System (INIS)
Shrivastava, K.N.
1980-01-01
A magnon-photon interaction for the magnetic vector of the electromagnetic wave perpendicular to the direction of magnetization in a ferromagnet is constructed. The magnon part of the interaction is reduced with the use of Bogoliubov transformation. The resulting magnon-photon interaction is found to contain several interesting new radiation effects. The self energy of the magnon is calculated and life times arising from the radiation scattering are predicted. The magnon frequency shift due to the radiation field is found. One of the terms arising from the one-magnon one-photon scattering gives a line width in reasonable agreement with the experimentally measured value of ferromagnetic resonance line width in yttrium iron garnet. Surface magnon scattering is indicated and the contribution of this type of scattering to the radiative line width is discussed. The problem of magnetic superradiance is indicated and it is shown that in anisotropic ferromagnets the emission is proportional to the sqare of the number of magnons and the divergence is considerably minimized. Accordingly the magnetic superradiance emerges as a hyperradiance with much more radiation intensity than in the case of disordered atomic superradiance. (author)
DEFF Research Database (Denmark)
Keller, Ole
2002-01-01
train quantum electrodynamics. A brief description of particle (photon) position operators is given, and it is shown that photons usually are only algebraically confined in an emission process. Finally, it is demonstrated that the profile of the birth domain of a radio-frequency photon emitted...
Gravitational Bhabha scattering
International Nuclear Information System (INIS)
Santos, A F; Khanna, Faqir C
2017-01-01
Gravitoelectromagnetism (GEM) as a theory for gravity has been developed similar to the electromagnetic field theory. A weak field approximation of Einstein theory of relativity is similar to GEM. This theory has been quantized. Traditional Bhabha scattering, electron–positron scattering, is based on quantized electrodynamics theory. Usually the amplitude is written in terms of one photon exchange process. With the development of quantized GEM theory, the scattering amplitude will have an additional component based on an exchange of one graviton at the lowest order of perturbation theory. An analysis will provide the relative importance of the two amplitudes for Bhabha scattering. This will allow an analysis of the relative importance of the two amplitudes as the energy of the exchanged particles increases. (paper)
Topology optimization of nano-photonic systems
DEFF Research Database (Denmark)
Elesin, Yuriy; Wang, Fengwen; Andkjær, Jacob Anders
2012-01-01
We describe recent developments within nano-photonic systems design based on topology optimization. Applications include linear and non-linear optical waveguides, slow-light waveguides, as well as all-dielectric cloaks that minimize scattering or back-scattering from hard obstacles.......We describe recent developments within nano-photonic systems design based on topology optimization. Applications include linear and non-linear optical waveguides, slow-light waveguides, as well as all-dielectric cloaks that minimize scattering or back-scattering from hard obstacles....
Fano resonance in anodic aluminum oxide based photonic crystals.
Shang, Guo Liang; Fei, Guang Tao; Zhang, Yao; Yan, Peng; Xu, Shao Hui; Ouyang, Hao Miao; Zhang, Li De
2014-01-08
Anodic aluminum oxide based photonic crystals with periodic porous structure have been prepared using voltage compensation method. The as-prepared sample showed an ultra-narrow photonic bandgap. Asymmetric line-shape profiles of the photonic bandgaps have been observed, which is attributed to Fano resonance between the photonic bandgap state of photonic crystal and continuum scattering state of porous structure. And the exhibited Fano resonance shows more clearly when the sample is saturated ethanol gas than air-filled. Further theoretical analysis by transfer matrix method verified these results. These findings provide a better understanding on the nature of photonic bandgaps of photonic crystals made up of porous materials, in which the porous structures not only exist as layers of effective-refractive-index material providing Bragg scattering, but also provide a continuum light scattering state to interact with Bragg scattering state to show an asymmetric line-shape profile.
Entanglement degradation in depolarizing light scattering
International Nuclear Information System (INIS)
Aiello, A.; Woerdman, J.P.
2005-01-01
Full text: In the classical regime, when a beam of light is scattered by a medium, it may emerge partially or completely depolarized depending on the optical properties of the medium. Correspondingly, in the quantum regime, when an entangled two-photon pair is scattered, the classical depolarization may result in an entanglement degradation. Here, relations between photon scattering, entanglement and multi-mode detection are investigated. We establish a general framework in which one- and two-photon elastic scattering processes can be discussed, and we focus on the study of the intrinsic entanglement degradation caused by a multi-mode detection. We show that any multi-mode scattered state cannot maximally violate the Bell-CHSH inequality because of the momentum spread. The results presented here have general validity and can be applied to both deterministic and random scattering processes. (author)
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
Silicon photonics fundamentals and devices
Deen, M Jamal
2012-01-01
The creation of affordable high speed optical communications using standard semiconductor manufacturing technology is a principal aim of silicon photonics research. This would involve replacing copper connections with optical fibres or waveguides, and electrons with photons. With applications such as telecommunications and information processing, light detection, spectroscopy, holography and robotics, silicon photonics has the potential to revolutionise electronic-only systems. Providing an overview of the physics, technology and device operation of photonic devices using exclusively silicon and related alloys, the book includes: * Basic Properties of Silicon * Quantum Wells, Wires, Dots and Superlattices * Absorption Processes in Semiconductors * Light Emitters in Silicon * Photodetectors , Photodiodes and Phototransistors * Raman Lasers including Raman Scattering * Guided Lightwaves * Planar Waveguide Devices * Fabrication Techniques and Material Systems Silicon Photonics: Fundamentals and Devices outlines ...
Continuous Energy Photon Transport Implementation in MCATK
Energy Technology Data Exchange (ETDEWEB)
Adams, Terry R. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Trahan, Travis John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Sweezy, Jeremy Ed [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Nolen, Steven Douglas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hughes, Henry Grady [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Pritchett-Sheats, Lori A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Werner, Christopher John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2016-10-31
The Monte Carlo Application ToolKit (MCATK) code development team has implemented Monte Carlo photon transport into the MCATK software suite. The current particle transport capabilities in MCATK, which process the tracking and collision physics, have been extended to enable tracking of photons using the same continuous energy approximation. We describe the four photoatomic processes implemented, which are coherent scattering, incoherent scattering, pair-production, and photoelectric absorption. The accompanying background, implementation, and verification of these processes will be presented.
Tsia, Kevin K.; Jalali, Bahram
2010-05-01
An intriguing optical property of silicon is that it exhibits a large third-order optical nonlinearity, with orders-ofmagnitude larger than that of silica glass in the telecommunication band. This allows efficient nonlinear optical interaction at relatively low power levels in a small footprint. Indeed, we have witnessed a stunning progress in harnessing the Raman and Kerr effects in silicon as the mechanisms for enabling chip-scale optical amplification, lasing, and wavelength conversion - functions that until recently were perceived to be beyond the reach of silicon. With all the continuous efforts developing novel techniques, nonlinear silicon photonics is expected to be able to reach even beyond the prior achievements. Instead of providing a comprehensive overview of this field, this manuscript highlights a number of new branches of nonlinear silicon photonics, which have not been fully recognized in the past. In particular, they are two-photon photovoltaic effect, mid-wave infrared (MWIR) silicon photonics, broadband Raman effects, inverse Raman scattering, and periodically-poled silicon (PePSi). These novel effects and techniques could create a new paradigm for silicon photonics and extend its utility beyond the traditionally anticipated applications.
Coupling the photon kinetics of soft photons with high energy photons
Silva, L. O.; Bingham, R.
2017-10-01
The description of electromagnetic fields based on the generalized photon kinetic theory, which takes advantage of the Wigner-Moyal description for the corresponding classical field theory, is capable of capturing collective plasma dynamics in the relativistic regime driven by broadband incoherent or partially coherent sources. We explore the possibility to extend this description to include the dynamics of hard photons in the plasma, whose interaction is dominated by single scattering processes. Examples of the modification of classical plasma instabilities due to the presence of hard photons is discussed. Work supported by the European Research Council (ERC-AdG-2015 InPairs Grant No. 695088).
Scattering in an intense radiation field: Time-independent methods
International Nuclear Information System (INIS)
Rosenberg, L.
1977-01-01
The standard time-independent formulation of nonrelativistic scattering theory is here extended to take into account the presence of an intense external radiation field. In the case of scattering by a static potential the extension is accomplished by the introduction of asymptotic states and intermediate-state propagators which account for the absorption and induced emission of photons by the projectile as it propagates through the field. Self-energy contributions to the propagator are included by a systematic summation of forward-scattering terms. The self-energy analysis is summarized in the form of a modified perturbation expansion of the type introduced by Watson some time ago in the context of nuclear-scattering theory. This expansion, which has a simple continued-fraction structure in the case of a single-mode field, provides a generally applicable successive approximation procedure for the propagator and the asymptotic states. The problem of scattering by a composite target is formulated using the effective-potential method. The modified perturbation expansion which accounts for self-energy effects is applicable here as well. A discussion of a coupled two-state model is included to summarize and clarify the calculational procedures
Photonic and plasmonic guided modes in graphene-silicon photonic crystals
DEFF Research Database (Denmark)
Gu, Tingyi; Andryieuski, Andrei; Hao, Yufeng
2016-01-01
We report the results of systematic studies of plasmonic and photonic guided modes in large-area single-layer graphene integrated into a nanostructured silicon substrate. The interaction of light with graphene and substrate photonic crystals can be classified in distinct regimes of plasmonic...... and photonic modes....
Direct photon production and PDF fits reloaded
Campbell, John M.; Rojo, Juan; Slade, Emma; Williams, Ciaran
2018-01-01
Direct photon production in hadronic collisions provides a handle on the gluon PDF by means of the QCD Compton scattering process. In this work we revisit the impact of direct photon production on a global PDF analysis, motivated by the recent availability of the next-to-next-to-leading (NNLO)
Photon transport in thin disordered slabs
Indian Academy of Sciences (India)
We examine using Monte Carlo simulations, photon transport in optically `thin' slabs whose thickness is only a few times the transport mean free path *, with particles of different scattering anisotropies. The conﬁned geometry causes an auto-selection of only photons with looping paths to remain within the slab.
Photon Dispersion in a Supernova Core
Kopf, A.; Raffelt, G.
1997-01-01
While the photon forward-scattering amplitude on free magnetic dipoles (e.g. free neutrons) vanishes, the nucleon magnetic moments still contribute significantly to the photon dispersion relation in a supernova (SN) core where the nucleon spins are not free due to their interaction. We study the frequency dependence of the relevant spin susceptibility in a toy model with only neutrons which interact by one-pion exchange. Our approach amounts to calculating the photon absorption rate from the ...
Photon Linear Collider Gamma-Gamma Summary
International Nuclear Information System (INIS)
Gronberg, J.
2012-01-01
High energy photon - photon collisions can be achieved by adding high average power short-pulse lasers to the Linear Collider, enabling an expanded physics program for the facility. The technology required to realize a photon linear collider continues to mature. Compton back-scattering technology is being developed around the world for low energy light source applications and high average power lasers are being developed for Inertial Confinement Fusion.
Directory of Open Access Journals (Sweden)
Evgenii E. Narimanov
2014-10-01
Full Text Available We introduce a new “universality class” of artificial optical media—photonic hypercrystals. These hyperbolic metamaterials, with periodic spatial variation of dielectric permittivity on subwavelength scale, combine the features of optical metamaterials and photonic crystals. In particular, surface waves supported by a hypercrystal possess the properties of both the optical Tamm states in photonic crystals and surface-plasmon polaritons at the metal-dielectric interface.
Lee, Chi H
2006-01-01
Wireless, optical, and electronic networks continue to converge, prompting heavy research into the interface between microwave electronics, ultrafast optics, and photonic technologies. New developments arrive nearly as fast as the photons under investigation, and their commercial impact depends on the ability to stay abreast of new findings, techniques, and technologies. Presenting a broad yet in-depth survey, Microwave Photonics examines the major advances that are affecting new applications in this rapidly expanding field.This book reviews important achievements made in microwave photonics o
Bottom-up Fabrication of Multilayer Stacks of 3D Photonic Crystals from Titanium Dioxide.
Kubrin, Roman; Pasquarelli, Robert M; Waleczek, Martin; Lee, Hooi Sing; Zierold, Robert; do Rosário, Jefferson J; Dyachenko, Pavel N; Montero Moreno, Josep M; Petrov, Alexander Yu; Janssen, Rolf; Eich, Manfred; Nielsch, Kornelius; Schneider, Gerold A
2016-04-27
A strategy for stacking multiple ceramic 3D photonic crystals is developed. Periodically structured porous films are produced by vertical convective self-assembly of polystyrene (PS) microspheres. After infiltration of the opaline templates by atomic layer deposition (ALD) of titania and thermal decomposition of the polystyrene matrix, a ceramic 3D photonic crystal is formed. Further layers with different sizes of pores are deposited subsequently by repetition of the process. The influence of process parameters on morphology and photonic properties of double and triple stacks is systematically studied. Prolonged contact of amorphous titania films with warm water during self-assembly of the successive templates is found to result in exaggerated roughness of the surfaces re-exposed to ALD. Random scattering on rough internal surfaces disrupts ballistic transport of incident photons into deeper layers of the multistacks. Substantially smoother interfaces are obtained by calcination of the structure after each infiltration, which converts amorphous titania into the crystalline anatase before resuming the ALD infiltration. High quality triple stacks consisting of anatase inverse opals with different pore sizes are demonstrated for the first time. The elaborated fabrication method shows promise for various applications demanding broadband dielectric reflectors or titania photonic crystals with a long mean free path of photons.
Depth distribution of multiple order X-ray scatter
International Nuclear Information System (INIS)
Yao Weiguang; Leszczynski, Konrad
2008-01-01
Scatter can significantly affect quality of projectional X-ray radiographs and tomographic reconstructions. With this in mind, we examined some of the physical properties of multiple orders of scatter of X-ray photons traversing through a layer of scattering media such as water. Using Monte Carlo techniques, we investigated depth distributions of interactions between incident X-ray photons and water before the resulting scattered photons reach the detector plane. Effects of factors such as radiation field size, air gap, thickness of the layer of scattering medium and X-ray energy, on the scatter were included in the scope of this study. The following scatter characteristics were observed: (1) for a layer of scattering material corresponding to the typical subject thickness in medical imaging, frequency distribution of locations of the last scattering interaction increases approximately exponentially with depth, and the higher the order of scatter or the energy of the incident photon, the narrower is the distribution; (2) for the second order scatter, the distribution of locations of the first interaction is more uniform than that of the last interaction and is dependent on the energy of the primary photons. Theoretical proofs for some of these properties are given. These properties are important to better understanding of effects of scatter on the radiographic and tomographic imaging process and to developing effective methods for scatter correction
International Nuclear Information System (INIS)
MacDougall, N.D.; Pitchford, W.G.; Smith, M.A.
2002-01-01
The purpose of this work is to undertake a critical appraisal of the evidence in the published literature concerning the basic parameters of accuracy and precision associated with the use of Fricke and polymer gels (in conjunction with MR imaging) as radiation dosimeters in photon radiotherapy, condensing and analysing the body of published information (to the end of April 2002). A systematic review was undertaken addressing specific issues of precision and accuracy asking defined questions of the published literature. Accuracy and precision in relation to gel dosimetry were defined. Information was obtained from published, peer-reviewed journals. A defined search strategy utilizing MeSH headings and keywords, with extensive use of cross-referencing, identified 115 references dealing with gel dosimetry. Exclusion criteria were used to select only data from publications which would give unequivocal evidence. For accuracy, results had to be compared with an ionization chamber as gold standard and all gel samples had to be manufactured in the same batch. For precision, in addition to gels being from the same batch, samples must all have been irradiated at the same time and scanned simultaneously (or within a short time frame). Many results were found demonstrating 'dose mapping' examples using gels. However, there were very few publications containing firm evidence of precision and accuracy. There was no evidence which fulfilled our criteria about accuracy or precision using Fricke gels. For polymer gels only one paper was found for accuracy (4% (Low et al 1999 Med. Phys. 26 1542-51)) and precision (1.7% (Baldock et al 1998 Phys. Med. Biol. 43 695-702)); however, both were carried out at only one dose level. If the exclusion criteria were relaxed to include accuracy results comparing gel to a non gold standard dosimeter (e.g. TLD), results give a median accuracy of 10% (range 8-23.5%) for polymer gel (Cosgrove et al 2000 Phys. Med. Biol. 45 1195-210, De Deene et al
A study of low Q2 radiative Bhabha scattering
International Nuclear Information System (INIS)
Karlen, D.A.
1988-03-01
This thesis presents a study of electron-positron scattering, via nearly real photon exchange, where in the process one or more high energy photons are produced. The motivations behind the work are twofold. Firstly, the study is a sensitive test of the theory of electron-photon interactions, quantum electrodynamics. A deviation from the theory could indicate that the electron is a composite particle. Secondly, a thorough understanding of this process is necessary for experiments to be done in the near future at the Stanford Linear Collider and the LEP facility at CERN. Calculations for the process to third and fourth order in pertubation theory are described. Methods for simulating the process by a Monte Carlo event generator are given. Results from the calculations are compared to data from the Mark II experiment at the PEP storage ring. The ratio of measured to calculated cross sections are 0.993 /+-/ 0.017 /+-/ 0.015 and 0.99 /+-/ 0.16 /+-/ 0.08 for final states with one and two observed photons respectively, where the first errors are statistical and the second systematic. The excellent agreement verifies the calculations of the fourth order radiative correction. No evidence for electron substructure is observed
Quenching effects in photon production
International Nuclear Information System (INIS)
Durand, M.
1989-01-01
Contraints on the photon production calculated by kinetic approaches are studied by means of sum-rules a finite temperature for simple quantum system. For the square-well potential the exact production rate is compared with its semi-classical limit in order to introduce the principle problem. For the scattering of hard spheres the photon production cross section is derived exactly by partial wave expansion. This serves to study the more realistic example of a gas of hard spheres. The corresponding kinetic photon production rates are found to violate the sum-rules, due to a singular behaviour at small gamma energies. Thus the hypothesis of incoherent free scattering is not valid in that range because of destructive interferences which quench the production rates significantly. For the application to nuclear collisions at intermediate energies these quenching effects are found to be important for gamma energies even up to a few hundred MeV. (orig.)
Practical model for the calculation of multiply scattered lidar returns
International Nuclear Information System (INIS)
Eloranta, E.W.
1998-01-01
An equation to predict the intensity of the multiply scattered lidar return is presented. Both the scattering cross section and the scattering phase function can be specified as a function of range. This equation applies when the cloud particles are larger than the lidar wavelength. This approximation considers photon trajectories with multiple small-angle forward-scattering events and one large-angle scattering that directs the photon back toward the receiver. Comparisons with Monte Carlo simulations, exact double-scatter calculations, and lidar data demonstrate that this model provides accurate results. copyright 1998 Optical Society of America
Liquid filling of photonic crystal fibres for grating writing
DEFF Research Database (Denmark)
Sørensen, Henrik Rokkjær; Canning, John; Lægsgaard, Jesper
2007-01-01
liquid filling of photonic crystal fibres reduces the scattering from air–glass interfaces during Bragg grating writing in many layered photonic crystal fibres. Within experimental uncertainty, the grating index modulation of a grating written in germanium-doped photonic crystal fibre with 10 rings...
Magnon-photon interaction in ferromagnets
International Nuclear Information System (INIS)
Shrivastava, K.N.
1980-01-01
A magnon-photon interaction for the magnetic vector of the electromagnetic wave perpendicular to the direction of magnetization in a ferromagnet is constructed with the use of Bogoliubov transformation. The resulting magnon-photon interaction is found to contain several interesting new radiation effects. The self-energy of the magnon is calculated and life times arising from the radiation scattering are predicted. The magnon frequency shift due to the radiation field is found. One of the terms arising from the one-magnon one-photon scattering gives a line width that is in reasonable agreement with the experimentally measured value of ferromagnetic resonance line width in yttrium iron garnet. (orig.)
Prompt photons in photoproduction at HERA
International Nuclear Information System (INIS)
Aaron, F.D.; Alexa, C.; Rotaru, M.; Stoicea, G.; Zus, R.; Aldaya Martin, M.; Antunovic, B.; Bartel, W.; Brandt, G.; Campbell, A.J.; Cholewa, A.; Deak, M.; Boer, Y. de; Eckerlin, G.; Elsen, E.; Felst, R.; Fischer, D.J.; Fleischer, M.; Gayler, J.; Glazov, A.; Gouzevitch, M.; Grell, B.R.; Haidt, D.; Helebrant, C.; Jung, H.; Katzy, J.; Kleinwort, C.; Knutsson, A.; Kraemer, M.; Krastev, K.; Kutak, K.; Levonian, S.; Lipka, K.; List, J.; Marti, Ll.; Meyer, A.B.; Meyer, H.; Meyer, J.; Michels, V.; Niebuhr, C.; Nikiforov, A.; Nozicka, M.; Olsson, J.E.; Panagoulias, I.; Papadopoulou, T.; Pitzl, D.; Placakyte, R.; Radescu, V.; Rurikova, Z.; Schmitt, S.; Sefkow, F.; Staykova, Z.; Steder, M.; Vargas Trevino, A.; Vinokurova, S.; Driesch, M. von den; Wissing, C.; Wuensch, E.; Andreev, V.; Belousov, A.; Eliseev, A.; Fomenko, A.; Gogitidze, N.; Lebedev, A.; Loktionova, N.; Malinovski, E.; Rusakov, S.; Shtarkov, L.N.; Soloviev, Y.; Vazdik, Y.; Backovic, S.; Dubak, A.; Lastovicka-Medin, G.; Picuric, I.; Raicevic, N.; Baghdasaryan, A.; Ghazaryan, S.; Volchinski, V.; Zohrabyan, H.; Barrelet, E.; Begzsuren, K.; Ravdandorj, T.; Tseepeldorj, B.; Bizot, J.C.; Brisson, V.; Delcourt, B.; Jacquet, M.; Li, G.; Pascaud, C.; Tran, T.H.; Zhang, Z.; Zomer, F.; Boudry, V.; Moreau, F.; Specka, A.; Bozovic-Jelisavcic, I.; Mudrinic, M.; Pandurovic, M.; Smiljanic, I.; Bracinik, J.; Kenyon, I.R.; Newman, P.R.; Shaw-West, R.N.; Thompson, P.D.; Brinkmann, M.; Habib, S.; List, B.; Pokorny, B.; Toll, T.; Bruncko, D.; Cerny, V.; Ferencei, J.; Murin, P.; Tomasz, F.; Bunyatyan, A.; Buschhorn, G.; Chekelian, V.; Dossanov, A.; Grindhammer, G.; Kiesling, C.; Kogler, R.; Liptaj, A.; Olivier, B.; Raspiareza, A.; Shushkevich, S.; Bystritskaya, L.; Efremenko, V.; Fedotov, A.; Kropivnitskaya, A.; Lubimov, V.; Ozerov, D.; Petrukhin, A.; Rostovtsev, A.; Zhokin, A.; Cantun Avila, K.B.; Contreras, J.G.; Ruiz Tabasco, J.E.; Cerny, K.; Pejchal, O.; Polifka, R.; Salek, D.; Valkarova, A.; Zacek, J.; Coughlan, J.A.; Morris, J.V.; Sankey, D.P.C.; Cozzika, G.; Feltesse, J.; Perez, E.; Schoeffel, L.; Cvach, J.; Reimer, P.; Zalesak, J.; Dainton, J.B.; Gabathuler, E.; Greenshaw, T.; Klein, M.; Kluge, T.; Kretzschmar, J.; Laycock, P.; Maxfield, S.J.; Mehta, A.; Patel, G.D.; Rahmat, A.J.; Daum, K.; Meyer, H.; Del Degan, M.; Grab, C.; Leibenguth, G.; Sauter, M.; Zimmermann, T.; Delvax, J.; Wolf, E.A. de; Favart, L.; Hreus, T.; Janssen, X.; Marage, P.; Mozer, M.U.; Roland, B.; Roosen, R.; Sunar, D.; Sykora, T.; Mechelen, P. van; Diaconu, C.; Hoffmann, D.; Sauvan, E.; Trinh, T.N.; Vallee, C.; Dodonov, V.; Povh, B.; Egli, S.; Hildebrandt, M.; Horisberger, R.; Falkiewicz, A.; Goerlich, L.; Mikocki, S.; Milcewicz-Mika, I.; Nowak, G.; Sopicki, P.; Turnau, J.; Glushkov, I.; Henschel, H.; Hiller, K.H.; Kostka, P.; Lange, W.; Naumann, T.; Piec, S.; Henderson, R.C.W.; Sloan, T.; Hennekemper, E.; Herbst, M.; Jung, A.W.; Krueger, K.; Lendermann, V.; Schultz-Coulon, H.C.; Urban, K.; Herrera, G.; Lopez-Fernandez, R.; Joensson, L.; Osman, S.; Kapichine, M.; Makankine, A.; Morozov, A.; Nikitin, D.; Palichik, V.; Spaskov, V.; Tchoulakov, V.; Landon, M.P.J.; Rizvi, E.; Thompson, G.; Traynor, D.; Martyn, H.U.; Mueller, K.; Nowak, K.; Robmann, P.; Straumann, U.; Truoel, P.; Schoening, A.; South, D.; Wegener, D.; Stella, B.; Tsakov, I.
2010-01-01
The production of prompt photons is measured in the photoproduction regime of electron-proton scattering at HERA. The analysis is based on a data sample corresponding to a total integrated luminosity of 340 pb -1 collected by the H1 experiment. Cross sections are measured for photons with transverse momentum and pseudorapidity in the range 6 T γ γ γ and x p carried by the partons entering the hard scattering process. The correlation between the photon and the jet is also studied. The results are compared with QCD predictions based on the collinear and on the k T factorization approaches. (orig.) 7
Statistical properties of laser light scattering in Brownian medium
International Nuclear Information System (INIS)
Suwono; Santoso, Budi; Baiquni, A.
1983-01-01
Relationship between statistical properties of laser light scattering in Brownian medium and photon-counting distributions are described in detail. A coherence optical detection has been constructed and by using photon-counting technique the ensemble distribution of the scattered field within space and time coherence has been measured. Good agreement between theory and experiment is shown. (author)
J/Ψ-production of photon-photon colliders as a probe of the color octet mechanism
International Nuclear Information System (INIS)
Ma, J.P.; McKellar, B.H.J.; Paranavitane, C.B
1997-01-01
We study J/Ψ production at photon-photon colliders, which can be realised with Compton scattering of laser photons at e + e - colliders. We find that the production rate through the color-octet channel is comparable to that through the color-singlet channel. Experimentally the two mechanisms can be studied separately because the processes have different signals. (authors)
International Nuclear Information System (INIS)
Telnov, Valery
2001-01-01
High energy photon colliders (γγ, γe) based on backward Compton scattering of laser light is a very natural addition to e + e - linear colliders. In this report, we consider this option for the TESLA project. Recent study has shown that the horizontal emittance in the TESLA damping ring can be further decreased by a factor of four. In this case, the γγ luminosity in the high energy part of spectrum can reach about (1/3)L e + e - . Typical cross-sections of interesting processes in γγ collisions are higher than those in e + e - collisions by about one order of magnitude, so the number of events in γγ collisions will be more than that in e + e - collisions. Photon colliders can, certainly, give additional information and they are the best for the study of many phenomena. The main question is now the technical feasibility. The key new element in photon colliders is a very powerful laser system. An external optical cavity is a promising approach for the TESLA project. A free electron laser is another option. However, a more straightforward solution is ''an optical storage ring (optical trap)'' with a diode pumped solid state laser injector which is today technically feasible. This paper briefly reviews the status of a photon collider based on the linear collider TESLA, its possible parameters and existing problems
International Nuclear Information System (INIS)
Chapman, D.
1988-01-01
PHOTON has proven very useful in the development of the X17 superconducting wiggler beamline. Its use has determined the shielding required from the wiggler device to the very end of the beamline in the hutches and angiography section. Doses calculated by this program have been compared with experimental results from conventional bending magnet beamline with great success. In each case the program consistently overestimated the dose by factors ranging from 2 to 10. The reason for this overestimation is understood and was not refined further in the program in order to maintain some level of safety in the shielding calculations. PHOTON should prove useful in the design of any beamline. Its ability to calculate power deposited and spectra transmitted through nearly arbitrary beamline configurations as well as the scattered radiation doses through shielding walls make it a very powerful tool
Photon technology. Hard photon technology; Photon technology. Hard photon gijutsu
Energy Technology Data Exchange (ETDEWEB)
NONE
1997-03-01
For the application of photon to industrial technologies, in particular, a hard photon technology was surveyed which uses photon beams of 0.1-200nm in wavelength. Its features such as selective atom reaction, dense inner shell excitation and spacial high resolution by quantum energy are expected to provide innovative techniques for various field such as fine machining, material synthesis and advanced inspection technology. This wavelength region has been hardly utilized for industrial fields because of poor development of suitable photon sources and optical devices. The developmental meaning, usable time and issue of a hard photon reduction lithography were surveyed as lithography in ultra-fine region below 0.1{mu}m. On hard photon analysis/evaluation technology, the industrial use of analysis, measurement and evaluation technologies by micro-beam was viewed, and optimum photon sources and optical systems were surveyed. Prediction of surface and surface layer modification by inner shell excitation, the future trend of this process and development of a vacuum ultraviolet light source were also surveyed. 383 refs., 153 figs., 17 tabs.
International Nuclear Information System (INIS)
Wiersma, D.S.
2013-01-01
We discuss in detail the optical properties of complex photonic structures, in particular those with a dominating disorder component. We will focus on their general transport properties, as well as on their use as light sources (random lasers). The basis for the theory of multiple light scattering in random systems will be explained as a tutorial introduction to the topic, including the explicit calculation of the effect of coherent backscattering. We will discuss various structures that go beyond regular disordered ones, in particular Levy glasses, liquid crystals, and quasicrystals, and show examples of their optical properties both from a conceptual and practical point of view.
International Nuclear Information System (INIS)
Gupta, Sourendu
2007-01-01
In this talk I discuss measures of fluctuations, especially those leading to the proof that the quark gluon plasma indeed contains quarks. I discuss the quark mass dependence of the critical end point of QCD. Then I discuss probes of the QCD critical point. Non-gaussian behaviour of event-to-event fluctuations of conserved quantum numbers is one such probe. Another is due to the coupling of fluctuations in baryon number and electrical charge, giving rise to long range random fluctuations of local charge density which relax slowly. These fluctuations can scatter photons, giving rise to critical opalescence
Gupta, Sourendu
2007-02-01
In this talk I discuss measures of fluctuations, especially those leading to the proof that the quark gluon plasma indeed contains quarks. I discuss the quark mass dependence of the critical end point of QCD. Then I discuss probes of the QCD critical point. Non-gaussian behaviour of event-to-event fluctuations of conserved quantum numbers is one such probe. Another is due to the coupling of fluctuations in baryon number and electrical charge, giving rise to long range random fluctuations of local charge density which relax slowly. These fluctuations can scatter photons, giving rise to critical opalescence.
Energy Technology Data Exchange (ETDEWEB)
Gupta, Sourendu [Department of Theoretical Physics, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005 (India)
2007-02-15
In this talk I discuss measures of fluctuations, especially those leading to the proof that the quark gluon plasma indeed contains quarks. I discuss the quark mass dependence of the critical end point of QCD. Then I discuss probes of the QCD critical point. Non-gaussian behaviour of event-to-event fluctuations of conserved quantum numbers is one such probe. Another is due to the coupling of fluctuations in baryon number and electrical charge, giving rise to long range random fluctuations of local charge density which relax slowly. These fluctuations can scatter photons, giving rise to critical opalescence.
Raman scattering method and apparatus for measuring isotope ratios and isotopic abundances
International Nuclear Information System (INIS)
Harney, R.C.; Bloom, S.D.
1978-01-01
Raman scattering is used to measure isotope ratios and/or isotopic abundances. A beam of quasi-monochromatic photons is directed onto the sample to be analyzed, and the resulting Raman-scattered photons are detected and counted for each isotopic species of interest. These photon counts are treated mathematically to yield the desired isotope ratios or isotopic abundances
Hard processes in photon-photon interactions
International Nuclear Information System (INIS)
Duchovni, E.
1985-03-01
In this thesis, the existence of hard component in two-photon collisions is investigated. Due to the relative simplicity of the photon, such processes can be exactly calculated in QCD. Untagged (low Q 2 ) two-photon events are used. This leads to relatively high statistics, but to severe background problem due mainly to e + e - annihilation. The background contamination is reduced to a tolerable level using a special set of cuts. Moreover, the remaining contamination is shown to be calculable with a small systematic error. A large number of events of the hard ''γγ'' type is found. An attempt to explain these events using the simplest QCD diagram (the Born term) is done. This process is found to be capable of explaining only a 1/4 of the data. Other options like the constituent intercharge model, integer charged quarks, and higher order diagrams are therefore also discussed. The large cross-section for the production of ρ 0 ρ 0 pairs in ''γγ'' collisions has not been understood yet. Inorder to look at closely related processes, a search for φρ 0 and φφ was initiated. The cross-section for θπ + π - was found to be sizeable. Only upper limits for the production of φρ 0 and φφ are obtained
Progress in photon science basics and applications
2017-01-01
This book features chapters based on lectures presented by world-leading researchers of photon science from Russia and Japan at the first “STEPS Symposium on Photon Science” held in Tokyo in March 2015. It describes recent progress in the field of photon science, covering a wide range of interest to experts in the field, including laser-plasma interaction, filamentation and its applications, laser assisted electron scattering, exotic properties of light, ultrafast imaging, molecules and clusters in intense laser fields, photochemistry and spectroscopy of novel materials, laser-assisted material synthesis, and photon technology.
Srinivasan-Rao, Triveni
2002-01-01
A photon generator includes an electron gun for emitting an electron beam, a laser for emitting a laser beam, and an interaction ring wherein the laser beam repetitively collides with the electron beam for emitting a high energy photon beam therefrom in the exemplary form of x-rays. The interaction ring is a closed loop, sized and configured for circulating the electron beam with a period substantially equal to the period of the laser beam pulses for effecting repetitive collisions.
Schmidt, A.; O'Connor, C.; Bernauer, J. C.; Milner, R.
2018-01-01
The OLYMPUS experiment measured the cross-section ratio of positron-proton elastic scattering relative to electron-proton elastic scattering to look for evidence of hard two-photon exchange. To make this measurement, the experiment alternated between electron beam and positron beam running modes, with the relative integrated luminosities of the two running modes providing the crucial normalization. For this reason, OLYMPUS had several redundant luminosity monitoring systems, including a pair of electromagnetic calorimeters positioned downstream from the target to detect symmetric Møller and Bhabha scattering from atomic electrons in the hydrogen gas target. Though this system was designed to monitor the rate of events with single Møller/Bhabha interactions, we found that a more accurate determination of relative luminosity could be made by additionally considering the rate of events with both a Møller/Bhabha interaction and a concurrent elastic ep interaction. This method was improved by small corrections for the variance of the current within bunches in the storage ring and for the probability of three interactions occurring within a bunch. After accounting for systematic effects, we estimate that the method is accurate in determining the relative luminosity to within 0.36%. This precise technique can be employed in future electron-proton and positron-proton scattering experiments to monitor relative luminosity between different running modes.
Jet production in photon-photon interactions
International Nuclear Information System (INIS)
Berger, C.; Genzel, H.; Lackas, W.; Pielorz, J.; Raupach, F.; Wagner, W.; Buerger, J.; Criegee, L.; Deuter, A.; Franke, G.; Gerke, C.; Knies, G.; Lewendel, B.; Meyer, J.; Michelsen, U.; Pape, K.H.; Timm, U.; Winter, G.G.; Zimmermann, W.; Zachara, M.; Ferrarotto, F.; Gaspero, M.; Stella, B.; Bussey, P.J.; Cartwright, S.L.; Dainton, J.B.; Hendry, D.; King, B.T.; Raine, C.; Scarr, J.M.; Skillicorn, I.O.; Smith, K.M.; Thomson, J.C.; Achterberg, O.; Blobel, V.; Burkart, D.; Diehlmann, K.; Feindt, M.; Kapitza, H.; Koppitz, B.; Krueger, M.; Poppe, M.; Spitzer, H.; Staa, R. van; Almeida, F.; Baecker, A.; Barreiro, F.; Brandt, S.; Derikum, K.; Grupen, C.; Meyer, H.J.; Mueller, H.; Neumann, B.; Rost, M.; Stupperich, K.; Zech, G.; Alexander, G.; Bella, G.; Gnat, Y.; Grunhaus, J.; Junge, H.; Kraski, K.; Maxeiner, C.; Maxeiner, H.; Meyer, H.; Schmidt, D.
1987-01-01
We present results on jet production in γγ interactions where both photons are quasi-real. The invariant masses of the hadronic system are limited to the range 4≤W vis 12 GeV/c 2 . The data approach the Quark-Parton-Model (QPM) expectation at the highest p T jet values (≥4 GeV/c). Jet production at low p T (≤1 GeV/c) can be described by a Vector Dominance derived model. The data also have a component with no apparent jet structure in the range, 1.0≤p T jet ≤4.0 GeV/c which can be described by phase space or by models of the QCD hard scattering processes γγ→qanti qg and γγ→qanti qqanti q. (orig.)
Angular distribution of 662keV multiply-Compton scattered gamma rays in copper
International Nuclear Information System (INIS)
Singh, Manpreet; Singh, Gurvinderjit; Sandhu, B.S.; Singh, Bhajan
2007-01-01
The angular distribution of multiple Compton scattering of 662keV gamma photons, obtained from six Curie 137 Cs source, incident on copper scatterer of varying thickness is studied experimentally in both the forward and backward hemispheres. The scattered photons are detected by a 51mmx51mm NaI(Tl) scintillation detector. The full-energy peak corresponding to singly scattered events is reconstructed analytically. We observe that the numbers of multiply scattered events, having same energy as in the singly scattered distribution, first increases with increase in target thickness and then saturate. The optimum thickness at which the multiply scattered events saturate is determined at different scattering angles
Toth, Laszlo Daniel
2013-01-01
Disordered photonics is the study of light in random media. In a disordered photonic medium, multiple scattering of light and coherence, together with the fundamental principle of reciprocity, produce a wide range of interesting phenomena
Hybrid colloidal plasmonic-photonic crystals.
Romanov, Sergei G; Korovin, Alexander V; Regensburger, Alois; Peschel, Ulf
2011-06-17
We review the recently emerged class of hybrid metal-dielectric colloidal photonic crystals. The hybrid approach is understood as the combination of a dielectric photonic crystal with a continuous metal film. It allows to achieve a strong modification of the optical properties of photonic crystals by involving the light scattering at electronic excitations in the metal component into moulding of the light flow in series to the diffraction resonances occurring in the body of the photonic crystal. We consider different realizations of hybrid plasmonic-photonic crystals based on two- and three-dimensional colloidal photonic crystals in association with flat and corrugated metal films. In agreement with model calculations, different resonance phenomena determine the optical response of hybrid crystals leading to a broadly tuneable functionality of these crystals. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Single Crystal Diffuse Neutron Scattering
Directory of Open Access Journals (Sweden)
Richard Welberry
2018-01-01
Full Text Available Diffuse neutron scattering has become a valuable tool for investigating local structure in materials ranging from organic molecular crystals containing only light atoms to piezo-ceramics that frequently contain heavy elements. Although neutron sources will never be able to compete with X-rays in terms of the available flux the special properties of neutrons, viz. the ability to explore inelastic scattering events, the fact that scattering lengths do not vary systematically with atomic number and their ability to scatter from magnetic moments, provides strong motivation for developing neutron diffuse scattering methods. In this paper, we compare three different instruments that have been used by us to collect neutron diffuse scattering data. Two of these are on a spallation source and one on a reactor source.
Photonic and Plasmonic Guided Modes in Graphene-Silicon Photonic Crystals
DEFF Research Database (Denmark)
Gu, Tingyi; Andryieuski, Andrei; Hao, Yufeng
2015-01-01
We report the results of systematic studies of plasmonic and photonic guided modes in large-area single-layer graphene integrated into a nanostructured silicon substrate. The interaction of light with graphene and substrate photonic crystals can be classified in distinct regimes depending......, filters, sensors, and photodetectors utilizing silicon photonic platforms....... on the relation of the photonic crystal lattice constant and the relevant modal wavelengths, that is, plasmonic, photonic, and free-space. By optimizing the design of the substrate, these resonant modes can increase the absorption of graphene in the infrared, facilitating enhanced performance of modulators...
Photon structure and the production of jets, hadrons, and prompt photons
International Nuclear Information System (INIS)
Klasen, M.
1999-01-01
We give a pedagogical introduction to hard photoproduction processes at HERA, including the production of jets, hadrons, and prompt photons. Recent theoretical developments in the three areas are reviewed. In summary, hard photoproduction processes can provide very useful information on the hadronic structure of the photon, in particular on the gluon density, which is complimentary to the information coming from deep inelastic photon-photon scattering at electron-positron colliders. Among the different hadronic final states, jets are most easily accessible experimentally and phenomenologically. On the other hand, inclusive hadron production offers the possibility to test the universality of hadron fragmentation functions and measure the photon structure down to very low values of p T and x γ . Prompt photon production suffers from a reduced cross section and limited data, but allows for the additional testing of photon fragmentation functions
Parity-Time Symmetric Photonics
Zhao, Han
2018-01-17
The establishment of non-Hermitian quantum mechanics (such as parity-time (PT) symmetry) stimulates a paradigmatic shift for studying symmetries of complex potentials. Owing to the convenient manipulation of optical gain and loss in analogy to the complex quantum potentials, photonics provides an ideal platform for visualization of many conceptually striking predictions from the non-Hermitian quantum theory. A rapidly developing field has emerged, namely, PT symmetric photonics, demonstrating intriguing optical phenomena including eigenstate coalescence and spontaneous PT symmetry breaking. The advance of quantum physics, as the feedback, provides photonics with brand-new paradigms to explore the entire complex permittivity plane for novel optical functionalities. Here, we review recent exciting breakthroughs in PT symmetric photonics while systematically presenting their underlying principles guided by non-Hermitian symmetries. The potential device applications for optical communication and computing, bio-chemical sensing, and healthcare are also discussed.
International Nuclear Information System (INIS)
Berger, C.
1984-01-01
In principle we have to distinguish between three cases: In no-tag experiments, none of the outgoing leptons e + e - is detected. The photon flux is completely dominated by transversely polarized photons, which are practically on-mass-shell. In single-tag experiments, either the outgoing e - or e + is detected in a forward spectrometer. Sometimes the tagging information is only used for separating a multihadronic twophoton final state from e + e - annihilation states. On the other hand, the information from the forward detectors can be used to investigate the Q 2 behaviour of the cross-section. A combination of tagging on one side with antitagging on the other allows an easy interpretation of the results in terms of electron scattering off a real photon target. In double-tag experiments, both outgoing leptons are measured. In principle, the full kinematical structure of the process can be studied, but we are still a long way from starting to tackle this difficult task
Pearsall, Thomas P
2017-01-01
This textbook employs a pedagogical approach that facilitates access to the fundamentals of Quantum Photonics. It contains an introductory description of the quantum properties of photons through the second quantization of the electromagnetic field, introducing stimulated and spontaneous emission of photons at the quantum level. Schrödinger’s equation is used to describe the behavior of electrons in a one-dimensional potential. Tunneling through a barrier is used to introduce the concept of nonlocality of an electron at the quantum level, which is closely-related to quantum confinement tunneling, resonant tunneling, and the origin of energy bands in both periodic (crystalline) and aperiodic (non-crystalline) materials. Introducing the concepts of reciprocal space, Brillouin zones, and Bloch’s theorem, the determination of electronic band structure using the pseudopotential method is presented, allowing direct computation of the band structures of most group IV, group III-V, and group II-VI semiconducto...
Induced Compton scattering effects in radiation transport approximations
International Nuclear Information System (INIS)
Gibson, D.R. Jr.
1982-01-01
In this thesis the method of characteristics is used to solve radiation transport problems with induced Compton scattering effects included. The methods used to date have only addressed problems in which either induced Compton scattering is ignored, or problems in which linear scattering is ignored. Also, problems which include both induced Compton scattering and spatial effects have not been considered previously. The introduction of induced scattering into the radiation transport equation results in a quadratic nonlinearity. Methods are developed to solve problems in which both linear and nonlinear Compton scattering are important. Solutions to scattering problems are found for a variety of initial photon energy distributions
Induced Compton-scattering effects in radiation-transport approximations
International Nuclear Information System (INIS)
Gibson, D.R. Jr.
1982-02-01
The method of characteristics is used to solve radiation transport problems with induced Compton scattering effects included. The methods used to date have only addressed problems in which either induced Compton scattering is ignored, or problems in which linear scattering is ignored. Also, problems which include both induced Compton scattering and spatial effects have not been considered previously. The introduction of induced scattering into the radiation transport equation results in a quadratic nonlinearity. Methods are developed to solve problems in which both linear and nonlinear Compton scattering are important. Solutions to scattering problems are found for a variety of initial photon energy distributions
International Nuclear Information System (INIS)
Quan, Frederic
2012-01-01
Photonics, the broad merger of electronics with the optical sciences, encompasses such a wide swath of technology that its impact is almost universal in our everyday lives. This is a broad overview of some aspects of the industry and their contribution to the ‘green’ or environmental movement. The rationale for energy conservation is briefly discussed and the impact of photonics on our everyday lives and certain industries is described. Some opinions from industry are presented along with market estimates. References are provided to some of the most recent research in these areas. (review article)
The photon content of the proton
Manohar, Aneesh V.; Nason, Paolo; Salam, Gavin P.; Zanderighi, Giulia
2017-12-01
The photon PDF of the proton is needed for precision comparisons of LHC cross sections with theoretical predictions. In a recent paper, we showed how the photon PDF could be determined in terms of the electromagnetic proton structure functions F 2 and F L measured in electron-proton scattering experiments, and gave an explicit formula for the PDF including all terms up to next-to-leading order. In this paper we give details of the derivation. We obtain the photon PDF using the factorisation theorem and applying it to suitable BSM hard scattering processes. We also obtain the same PDF in a process-independent manner using the usual definition of PDFs in terms of light-cone Fourier transforms of products of operators. We show how our method gives an exact representation for the photon PDF in terms of F 2 and F L , valid to all orders in QED and QCD, and including all non-perturbative corrections. This representation is then used to give an explicit formula for the photon PDF to one order higher than our previous result. We also generalise our results to obtain formulæ for the polarised photon PDF, as well as the photon TMDPDF. Using our formula, we derive the P γ i subset of DGLAP splitting functions to order αα s and α 2, which agree with known results. We give a detailed explanation of the approach that we follow to determine a photon PDF and its uncertainty within the above framework.
Moran, Christine H.; Rycenga, Matthew; Zhang, Qiang; Xia, Younan
2011-01-01
In this work, we used surface-enhanced Raman scattering (SERS) to monitor the replacement of poly(vinyl pyrrolidone) (PVP) on Ag nanocubes by cysteamine, thiol-terminated PEG, and benzenedithiol. PVP is widely used as a colloidal stabilizer and capping agent to control the shape of Ag (as well as many other noble metals) nanocrystals during synthesis, and to stabilize the final colloidal suspension. However, the surface chemistry of Ag nanocrystals often needs to be tailored for specific appl...
Review and history of photon cross section calculations
International Nuclear Information System (INIS)
Hubbell, J H
2006-01-01
Photon (x-ray, gamma-ray, bremsstrahlung) mass attenuation coefficients, μ/ρ, are among the most widely used physical parameters employed in medical diagnostic and therapy computations, as well as in diverse applications in other fields such as nuclear power plant shielding, health physics and industrial irradiation and monitoring, and in x-ray crystallography. This review traces the evolution of this data base from its empirical beginnings totally derived from measurements beginning in 1907 by Barkla and Sadler and continuing up through the 1935 Allen compilation (published virtually unchanged in all editions up through 1971-1972 of the Chemical Rubber Handbook), to the 1949 semi-empirical compilation of Victoreen, as our theoretical understanding of the constituent Compton scattering, photoabsorption and pair production interactions of photons with atoms became more quantitative. The 1950s saw the advent of completely theoretical (guided by available measured data) systematic compilations such as in the works of Davisson and Evans, and by White-Grodstein under the direction of Fano, using mostly theory developed in the 1930s (pre-World War II) by Sauter, Bethe, Heitler and others. Post-World War II new theoretical activity, and the introduction of the electronic automatic computer, led to the more extensive and more accurate compilations in the 1960s and 1970s by Storm and Israel, and by Berger and Hubbell. Today's μ/ρ compilations by Cullen et al, by Seltzer, Berger and Hubbell, and by others, collectively spanning the ten decades of photon energy from 10 eV to 100 GeV, for all elements Z= 1 to 100, draw heavily on the 1970s shell-by-shell photoabsorption computations of Scofield, the 1960s coherent and incoherent scattering computations of Cromer et al, and the 1980 computations of electron-positron pair and triplet computations of Hubbell, Gimm and Oeverboe, these names being representative of the vast legions of other researchers whose work fed into these
Photon Subtraction by Many-Body Decoherence
DEFF Research Database (Denmark)
Murray, C. R.; Mirgorodskiy, I.; Tresp, C.
2018-01-01
We experimentally and theoretically investigate the scattering of a photonic quantum field from another stored in a strongly interacting atomic Rydberg ensemble. Considering the many-body limit of this problem, we derive an exact solution to the scattering-induced spatial decoherence of multiple...... stored photons, allowing for a rigorous understanding of the underlying dissipative quantum dynamics. Combined with our experiments, this analysis reveals a correlated coherence-protection process in which the scattering from one excitation can shield all others from spatial decoherence. We discuss how...... this effect can be used to manipulate light at the quantum level, providing a robust mechanism for single-photon subtraction, and experimentally demonstrate this capability....
Bose-Einstein condensation of photons from the thermodynamic limit to small photon numbers
Nyman, Robert A.; Walker, Benjamin T.
2018-03-01
Photons can come to thermal equilibrium at room temperature by scattering multiple times from a fluorescent dye. By confining the light and dye in a microcavity, a minimum energy is set and the photons can then show Bose-Einstein condensation. We present here the physical principles underlying photon thermalization and condensation, and review the literature on the subject. We then explore the 'small' regime where very few photons are needed for condensation. We compare thermal equilibrium results to a rate-equation model of microlasers, which includes spontaneous emission into the cavity, and we note that small systems result in ambiguity in the definition of threshold.
DEFF Research Database (Denmark)
Schjøth, Lars; Frisvad, Jeppe Revall; Erleben, Kenny
2007-01-01
illumination features. This is often not desirable as these may lose clarity or vanish altogether. We present an accurate method for reconstruction of indirect illumination with photon mapping. Instead of reconstructing illumination using classic density estimation on finite points, we use the correlation...
Indian Academy of Sciences (India)
Volume 2 Issue 5 May 1997 pp 69-72 Feature Article. Molecule of the Month Molecular–Chameleon: Solvatochromism at its Iridescent Best! Photon Rao · More Details Fulltext PDF. Volume 16 Issue 12 December 2011 pp 1303-1306. Molecule of the Month - Molecular-Chameleon: Solvatochromism at its Iridescent Best!
The Q2 and Transverse Momentum Dependence of Jet Production in Photon-Photon Interactions
International Nuclear Information System (INIS)
Tylka, Allan Joseph
1984-01-01
An experimental study of jet production in photon-photon interactions is presented. The study is based on events collected with the PLUTO detector at the e + e - storage ring PETRA. The data sample, which corresponds to an integrated luminosity of ∼40 pb -1 taken at an e + e - center-of- mass energy of 34.6 GeV, consists of 1226 events in the so-called 'single-tagged' mode, in which only one of the scattered beam electrons is detected. The data sample extends over the kinematic ranges 0.1 < Q 2 < 18.0. GeV , where Q 2 is the squared invariant mass of the tagged virtual photon, and jet transverse momentum (p T ) up to ∼5 GeV/c, where p T is measured with respect to the photon-photon collision axis in the center-of-mass frame of the observed hadrons. At all Q 2 the data show a high p T tail characteristic of hard, point-like interactions, as exemplified by the fundamental reaction γγ → qq-bar. The jet production cross-section approaches the standard Quark Parton Model (QPM) expectation for fractionally-charged quarks of three colors from above as either Q 2 or jet p T increases. At Q 2 ≥ 10 GeV the observed cross-section is consistent with the standard QPM to within ∼20% statistical uncertainty at all values of p T . This result rules out the naive Han-Nambu integrally-charged quark model at a level of about five standard deviations. It is demonstrated that overall the data are consistent with the hypothesis of a two-jet final state. Moreover, the total jet production cross-section is shown to be well-described by an incoherent sum of the Generalized Vector Dominance Model (GVDM), for which the final state is hadronized as two oppositely-directed low p T jets, and the QPM, which accounts for final states consisting of two high p T jets. Some discrepancies between the data and the GVDM+QPM Ansatz are observed. At Q 2 ≤ 1 GeV 2 and 1.5 ≤ jet p T ≤ 4.0 GeV/c, the data lie systematically above the GVDM+QPM prediction. The thrust distribution
Cardona, Manuel
2007-01-01
This is the ninth volume of a well-established series in which expert practitioners discuss topical aspects of light scattering in solids. It reviews recent developments concerning mainly semiconductor nanostructures and inelastic x-ray scattering, including both coherent time-domain and spontaneous scattering studies. In the past few years, light scattering has become one of the most important research and characterization methods for studying carbon nanotubes and semiconducting quantum dots, and a crucial tool for exploring the coupled exciton--photon system in semiconductor cavities. Among the novel techniques discussed in this volume are pump--probe ultrafast measurements and those which use synchrotron radiation as light source. The book addresses improvements in the intensity, beam quality and time synchronization of modern synchrotron sources, which made it possible to measure the phonon dispersion in very small samples and to determine electronic energy bands as well as enabling real-time observations...
International Nuclear Information System (INIS)
Hategan, Cornel; Comisel, Horia; Ionescu, Remus A.
2004-01-01
The quasiresonant scattering consists from a single channel resonance coupled by direct interaction transitions to some competing reaction channels. A description of quasiresonant Scattering, in terms of generalized reduced K-, R- and S- Matrix, is developed in this work. The quasiresonance's decay width is, due to channels coupling, smaller than the width of the ancestral single channel resonance (resonance's direct compression). (author)
Donne, A. J. H.
1994-01-01
Thomson scattering is a very powerful diagnostic which is applied at nearly every magnetic confinement device. Depending on the experimental conditions different plasma parameters can be diagnosed. When the wave vector is much larger than the plasma Debye length, the total scattered power is
On the validity of the equivalent-photon approximation for virtual photon-photon collisions
International Nuclear Information System (INIS)
Carimalo, C.; Kessler, P.; Parisi, J.
1979-05-01
For virtual photon-photon collisions in electron storage rings, one derive the equivalent-photon approximation from a helicity treatment, and present it in two forms, involving respectively (i) polarized transverse photons ('transverse-photon approximation') and (ii) unpolarized ones ('Williams-Weizsaecker approximation'). One first postulates the conditions of validity of the approximation on the basis of analytic considerations, and then check them numerically in the case of the process e e → e e μ + μ - . For this check, we consider the completely differentiated cross section as far as approximation (i) is concerned; and in the case of approximation (ii), the cross section differentiated with respect to all variables except the azimuthal angles. The results are given in the form of Tables showing the lower and higher limit of the error involved in the approximation for a large variety of kinematic configurations (i. e., energy losses and scattering angles of both electrons). Those Tables are discussed in detail, and conclusions are drawn as to the applicability of the equivalent-photon approximation to future experiments to be performed with high-energy electron storage rings
Optical properties of photonic crystals
Sakoda, Kazuaki
2001-01-01
The interaction between the radiation field and matter is the most fundamen tal source of dynamics in nature. It brings about the absorption and emission of photons, elastic and inelastic light scattering, the radiative lifetime of elec tronic excited states, and so on. The huge amount of energy carried from the sun by photons is the source of all activities of creatures on the earth. The absorption of photons by chlorophylls and the successive electronic excita tion initiate a series of chemical reactions that are known as photosynthesis, which support all life on the earth. Radiative energy is also the main source of all meteorological phenomena. The fundamentals of the radiation field and its interaction with matter were clarified by classical electromagnetism and quantum electrodynamics. These theories, we believe, explain all electromagnetic phenomena. They not only provide a firm basis for contemporary physics but also generate a vast range of technological applications. These include television, ...
Light-by-light scattering and muon's anomalous magnetic moment
International Nuclear Information System (INIS)
Pauk, Vladyslav
2014-01-01
A study of hadron production by photons opens unique ways to address a number of fundamental problems in strong interaction physics as well as fundamental questions in Quantum Field Theory. In particular, an understanding of two-photon processes is of crucial importance for constraining the hadronic uncertainties in precision measurements and in searches for new physics. The process of γ * γ * fusion (by quasi-real photons γ or virtual photons γ * ) into leptons and hadrons has been observed and studied in detail at nearly all high-energy colliders. From the theoretical point of view two-photon processes are very complicated. One of approaches which may be efficiently used to study non-perturbative features of two-photon production is based on a dispersion theory. Using general properties of relativistic quantum field theory we relate in this work the forward light-by-light scattering to energy weighted integrals of the γ * γ fusion cross sections. The first type of new relations derived in this work have the form of exact super-convergence sum rules. The second type involves the effective constants of the low-energy photon-photon interaction and allow to define them in terms of two-photon production cross sections. We subsequently test and verify these sum rules exactly at tree and one-loop level in scalar and spinor QED. Furthermore, we test the criterium of the tree-level unitarity imposed by the sum rules on the example of the massive spin-1 QED. Next, we apply the sum rules for the forward light-by-light scattering process within the context of the φ 4 quantum field theory. Within this theory, we present a stringent causality criterion and apply it to a particular non-perturbative resummation of graphs. Applied to the γ * γ production of mesons, the superconvergence sum rules lead to intricate relations between theγγ decay widths and the γ * γ transition form factors for (pseudo-) scalar, axial-vector and tensor mesons. We discuss the
Material-independent modes for electromagnetic scattering
Forestiere, Carlo; Miano, Giovanni
2016-11-01
In this Rapid Communication, we introduce a representation of the electromagnetic field for the analysis and synthesis of the full-wave scattering by a homogeneous dielectric object of arbitrary shape in terms of a set of eigenmodes independent of its permittivity. The expansion coefficients are rational functions of the permittivity. This approach naturally highlights the role of plasmonic and photonic modes in any scattering process and suggests a straightforward methodology to design the permittivity of the object to pursue a prescribed tailoring of the scattered field. We discuss in depth the application of the proposed approach to the analysis and design of the scattering properties of a dielectric sphere.
Scatter factor corrections for elongated fields
International Nuclear Information System (INIS)
Higgins, P.D.; Sohn, W.H.; Sibata, C.H.; McCarthy, W.A.
1989-01-01
Measurements have been made to determine scatter factor corrections for elongated fields of Cobalt-60 and for nominal linear accelerator energies of 6 MV (Siemens Mevatron 67) and 18 MV (AECL Therac 20). It was found that for every energy the collimator scatter factor varies by 2% or more as the field length-to-width ratio increases beyond 3:1. The phantom scatter factor is independent of which collimator pair is elongated at these energies. For 18 MV photons it was found that the collimator scatter factor is complicated by field-size-dependent backscatter into the beam monitor
The Monte Carlo simulation of the Ladon photon beam facility
International Nuclear Information System (INIS)
Strangio, C.
1976-01-01
The backward compton scattering of laser light against high energy electrons has been simulated with a Monte Carlo method. The main features of the produced photon beam are reported as well as a careful description of the numerical calculation
Photon propagators at finite temperature
International Nuclear Information System (INIS)
Yee, J.H.
1982-07-01
We have used the real time formalism to compute the one-loop finite temperature corrections to the photon self energies in spinor and scalar QED. We show that, for a real photon, only the transverse components develop the temperature-dependent masses, while, for an external static electromagnetic field applied to the finite temperature system, only the static electric field is screened by thermal fluctuations. After showing how to compute systematically the imaginary parts of the finite temperature Green functions, we have attempted to give a microscopic interpretation of the imaginary parts of the self energies. (author)
International Nuclear Information System (INIS)
Sitenko, A.
1991-01-01
This book emerged out of graduate lectures given by the author at the University of Kiev and is intended as a graduate text. The fundamentals of non-relativistic quantum scattering theory are covered, including some topics, such as the phase-function formalism, separable potentials, and inverse scattering, which are not always coverded in textbooks on scattering theory. Criticisms of the text are minor, but the reviewer feels an inadequate index is provided and the citing of references in the Russian language is a hindrance in a graduate text
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)
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)
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
Photons in a partonic transport approach
Energy Technology Data Exchange (ETDEWEB)
Greif, Moritz; Senzel, Florian; Greiner, Carsten [Goethe Universitaet Frankfurt, Max-von-Laue-Str. 1 60438 Frankfurt am Main (Germany)
2015-07-01
Partonic transport approaches have proved to be valuable tools in describing the quark-gluon plasma, created in heavy-ion collisions. In this work, first steps towards a dynamical understanding of photonproduction in expanding heavy-ion collisions are presented. Several photon production processes are included in the partonic cascade BAMPS (Boltzmann Approach to Multi-Parton Scatterings). BAMPS provides a microscopic tool to study expanding fireballs, employing a stochastic method to solve the relativistic 3+1d Boltzmann equation. Subsequently, photon spectra can be investigated, and in particular, the influence of the quark-gluon plasma phase for the elliptic flow of photons is studied.
Calculation of hadronic part of photon structure function in QCD
International Nuclear Information System (INIS)
Gorskij, A.S.; Ioffe, B.L.; Oganesyan, A.G.; Khodzhamiryan, A.Yu.
1989-01-01
The photon structure function in QCD in the intermediate region of the Bjorken variable 0.2 2 /2pq, where q 2 is the hard photon virtuality, p is the soft photon momentum) is calculated. It is shown that without introduction of fitting parameters the experimental data can be described in the range 3GeV 2 ≤Q 2 2 /Q 2 =-q 2 /not taking account for the leading logarithmic corrections. It is demonstrated that the corrections proportional to μ ν 2 > to the hard photon scattering amplitude on the longitudinal soft photon and to the Callan-Gross relation vanish. 16 refs.; 6 figs
Amorphous photonic crystals with only short-range order.
Shi, Lei; Zhang, Yafeng; Dong, Biqin; Zhan, Tianrong; Liu, Xiaohan; Zi, Jian
2013-10-04
Distinct from conventional photonic crystals with both short- and long-range order, amorphous photonic crystals that possess only short-range order show interesting optical responses owing to their unique structural features. Amorphous photonic crystals exhibit unique light scattering and transport, which lead to a variety of interesting phenomena such as isotropic photonic bandgaps or pseudogaps, noniridescent structural colors, and light localization. Recent experimental and theoretical advances in the study of amorphous photonic crystals are summarized, focusing on their unique optical properties, artificial fabrication, bionspiration, and potential applications. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
A triple spectrograph system for low stray light Thomson scattering measurements
Sande, van de M.J.; Mullen, van der J.J.A.M.
2001-01-01
Thomson scattering is scattering of photons by the electrons in a plasma. From the scattering spectrum, the electron temperature and density (Te, ne) of the plasma can be deduced. In the past decade, the development of high power lasers and sensitive detection devices has made Thomson scattering a
International Nuclear Information System (INIS)
Stirling, W.G.; Perry, S.C.
1996-01-01
We outline the theoretical and experimental background to neutron scattering studies of critical phenomena at magnetic and structural phase transitions. The displacive phase transition of SrTiO 3 is discussed, along with examples from recent work on magnetic materials from the rare-earth (Ho, Dy) and actinide (NpAs, NpSb, USb) classes. The impact of synchrotron X-ray scattering is discussed in conclusion. (author) 13 figs., 18 refs
Material science and neutron scattering
International Nuclear Information System (INIS)
1983-01-01
Neutron scattering experiments complete and extend the condensed matter studies made with X and gamma rays. Then story show a permanent evolution of the instrumentation, methods and experimental techniques to improve the result quality. This is more especially important as neutron sources are weaker than photon and electron sources. Progress in this research domain is due, in most part, to discovery and development of materials for the different measurement device components [fr
Wave propagation and scattering in random media
Ishimaru, Akira
1978-01-01
Wave Propagation and Scattering in Random Media, Volume 2, presents the fundamental formulations of wave propagation and scattering in random media in a unified and systematic manner. The topics covered in this book may be grouped into three categories: waves in random scatterers, waves in random continua, and rough surface scattering. Random scatterers are random distributions of many particles. Examples are rain, fog, smog, hail, ocean particles, red blood cells, polymers, and other particles in a state of Brownian motion. Random continua are the media whose characteristics vary randomly an
Energy Technology Data Exchange (ETDEWEB)
ZALIZNYAK,I.A.; LEE,S.H.
2004-07-30
Much of our understanding of the atomic-scale magnetic structure and the dynamical properties of solids and liquids was gained from neutron-scattering studies. Elastic and inelastic neutron spectroscopy provided physicists with an unprecedented, detailed access to spin structures, magnetic-excitation spectra, soft-modes and critical dynamics at magnetic-phase transitions, which is unrivaled by other experimental techniques. Because the neutron has no electric charge, it is an ideal weakly interacting and highly penetrating probe of matter's inner structure and dynamics. Unlike techniques using photon electric fields or charged particles (e.g., electrons, muons) that significantly modify the local electronic environment, neutron spectroscopy allows determination of a material's intrinsic, unperturbed physical properties. The method is not sensitive to extraneous charges, electric fields, and the imperfection of surface layers. Because the neutron is a highly penetrating and non-destructive probe, neutron spectroscopy can probe the microscopic properties of bulk materials (not just their surface layers) and study samples embedded in complex environments, such as cryostats, magnets, and pressure cells, which are essential for understanding the physical origins of magnetic phenomena. Neutron scattering is arguably the most powerful and versatile experimental tool for studying the microscopic properties of the magnetic materials. The magnitude of the cross-section of the neutron magnetic scattering is similar to the cross-section of nuclear scattering by short-range nuclear forces, and is large enough to provide measurable scattering by the ordered magnetic structures and electron spin fluctuations. In the half-a-century or so that has passed since neutron beams with sufficient intensity for scattering applications became available with the advent of the nuclear reactors, they have became indispensable tools for studying a variety of important areas of modern
International Nuclear Information System (INIS)
Lebrun, Didier.
1981-09-01
The giant monopole resonance has been studied via inelastic scattering of 108.5 MeV 3 He at very small angles (including 0 0 ) on approximately 50 nuclei. Its angular distribution reaches its maximum in this region and leads to clear separation with GQR. DWBA analysis shows a smooth increase of the strength from few per cent of the sum rule in light nuclei up to 100% in heavier ones. The excitation energy analysis shows a crossing effect of the monopole and quadrupole frequencies in A = 40-50 region, a coupling effect between the two modes in deformed nuclei, an asymmetry effect in several series of isotopes. Compressibility moduli of nuclear matter Ksub(infinity), surface Ksub(s) and asymmetry Ksub(tau) have seen extracted, as well as the Landau parameter F 0 at saturation [fr
Scattering of Non-Relativistic Charged Particles by Electromagnetic Radiation
Apostol, M.
2017-11-01
The cross-section is computed for non-relativistic charged particles (like electrons and ions) scattered by electromagnetic radiation confined to a finite region (like the focal region of optical laser beams). The cross-section exhibits maxima at scattering angles given by the energy and momentum conservation in multi-photon absorption or emission processes. For convenience, a potential scattering is included and a comparison is made with the well-known Kroll-Watson scattering formula. The scattering process addressed in this paper is distinct from the process dealt with in previous studies, where the scattering is immersed in the radiation field.
Towards a Resolution of the Proton Form Factor Problem: New Electron and Positron Scattering Data
Adikaram, D.; Rimal, D.; Weinstein, L. B.; Raue, B.; Khetarpal, P.; Bennett, R. P.; Arrington, J.; Brooks, W. K.; Adhikari, K. P.; Afanasev, A. V.; Amaryan, M. J.; Anderson, M. D.; Anefalos Pereira, S.; Avakian, H.; Ball, J.; Battaglieri, M.; Bedlinskiy, I.; Biselli, A. S.; Bono, J.; Boiarinov, S.; Briscoe, W. J.; Burkert, V. D.; Carman, D. S.; Careccia, S.; Celentano, A.; Chandavar, S.; Charles, G.; Colaneri, L.; Cole, P. L.; Contalbrigo, M.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Dodge, G. E.; Dupre, R.; Egiyan, H.; El Alaoui, A.; El Fassi, L.; Elouadrhiri, L.; Eugenio, P.; Fedotov, G.; Fegan, S.; Filippi, A.; Fleming, J. A.; Fradi, A.; Garillon, B.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Gohn, W.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guegan, B.; Guidal, M.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Harrison, N.; Hattawy, M.; Hicks, K.; Holtrop, M.; Hughes, S. M.; Hyde, C. E.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Jenkins, D.; Jiang, H.; Jo, H. S.; Joo, K.; Joosten, S.; Kalantarians, N.; Keller, D.; Khandaker, M.; Kim, A.; Kim, W.; Klein, A.; Klein, F. J.; Koirala, S.; Kubarovsky, V.; Kuhn, S. E.; Livingston, K.; Lu, H. Y.; MacGregor, I. J. D.; Markov, N.; Mattione, P.; Mayer, M.; McKinnon, B.; Mestayer, M. D.; Meyer, C. A.; Mirazita, M.; Mokeev, V.; Montgomery, R. A.; Moody, C. I.; Moutarde, H.; Movsisyan, A.; Camacho, C. Munoz; Nadel-Turonski, P.; Niccolai, S.; Niculescu, G.; Osipenko, M.; Ostrovidov, A. I.; Park, K.; Pasyuk, E.; Peña, C.; Pisano, S.; Pogorelko, O.; Price, J. W.; Procureur, S.; Prok, Y.; Protopopescu, D.; Puckett, A. J. R.; Ripani, M.; Rizzo, A.; Rosner, G.; Rossi, P.; Roy, P.; Sabatié, F.; Salgado, C.; Schott, D.; Schumacher, R. A.; Seder, E.; Sharabian, Y. G.; Simonyan, A.; Skorodumina, I.; Smith, E. S.; Smith, G. D.; Sober, D. I.; Sokhan, D.; Sparveris, N.; Stepanyan, S.; Stoler, P.; Strauch, S.; Sytnik, V.; Taiuti, M.; Tian, Ye; Trivedi, A.; Ungaro, M.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Watts, D. P.; Wei, X.; Wood, M. H.; Zachariou, N.; Zana, L.; Zhang, J.; Zhao, Z. W.; Zonta, I.; CLAS Collaboration
2015-02-01
There is a significant discrepancy between the values of the proton electric form factor, GEp, extracted using unpolarized and polarized electron scattering. Calculations predict that small two-photon exchange (TPE) contributions can significantly affect the extraction of GEp from the unpolarized electron-proton cross sections. We determined the TPE contribution by measuring the ratio of positron-proton to electron-proton elastic scattering cross sections using a simultaneous, tertiary electron-positron beam incident on a liquid hydrogen target and detecting the scattered particles in the Jefferson Lab CLAS detector. This novel technique allowed us to cover a wide range in virtual photon polarization (ɛ ) and momentum transfer (Q2) simultaneously, as well as to cancel luminosity-related systematic errors. The cross section ratio increases with decreasing ɛ at Q2=1.45 GeV2 . This measurement is consistent with the size of the form factor discrepancy at Q2≈1.75 GeV2 and with hadronic calculations including nucleon and Δ intermediate states, which have been shown to resolve the discrepancy up to 2 - 3 GeV2 .
International Nuclear Information System (INIS)
Deluca Silberberg, Carolina
2009-01-01
light mesons (π 0 and η) which decay into two very collinear photons. Since these photons are produced within a jet, they tend to be non-isolated in most of the cases, and can be suppressed by requiring the photon candidates to be isolated in the calorimeter. In the case the hard scattered parton hadronizes leaving most of its energy to the meson, the photon produced in the decay will not be surrounded by large energy depositions. To further reduce this remaining isolated background, we present a new technique based on the isolation distribution in the calorimeter. The measured cross section is compared to next-to-leading order (NLO) pQCD calculations, which have been corrected for non-perturbative contributions. This thesis is organized as follows: we start with a brief review of QCD theory and the formalism to calculate cross sections in Chapter 2, where we also introduce the physics of prompt photon production and summarize the current status of the prompt photon phenomenology. Chapter 3 contains a description of the Tevatron and the CDF detector. The experimental measurement is described in Chapter 4, where we provide details on the different datasets used in the measurement, the trigger, and the event selection requirements. Most of this Chapter is devoted to the explanation of the background subtraction method and the determination of the photon signal fraction. The systematic uncertainties on the measurement are evaluated in Chapter 5, while Chapter 6 discusses the final results and the comparison to the theoretical predictions. Finally, the conclusions are presented in Chapter 7.
Two-photon processes in highly charged ions
International Nuclear Information System (INIS)
Jahrsetz, Thorsten
2015-01-01
Two-photon processes are atomic processes in which an atom interacts simultaneously with two photons. Such processes describe a wide range of phenomena, such as two-photon decay and elastic or inelastic scattering of photons. In recent years two-photon processes involving highly charged heavy ions have become an active area of research. Such studies do not only consider the total transition or scattering rates but also their angular and polarization dependence. To support such examinations in this thesis I present a theoretical framework to describe these properties in all two-photon processes with bound initial and final states and involving heavy H-like or He-like ions. I demonstrate how this framework can be used in some detailed studies of different two-photon processes. Specifically a detailed analysis of two-photon decay of H-like and He-like ions in strong external electromagnetic fields shows the importance of considering the effect of such fields for the physics of such systems. Furthermore I studied the elastic Rayleigh as well as inelastic Raman scattering by heavy H-like ions. I found a number of previously unobserved phenomena in the angular and polarization dependence of the scattering cross-sections that do not only allow to study interesting details of the electronic structure of the ion but might also be useful for the measurement of weak physical effects in such systems.
State of the Art in Photon-Density Estimation
DEFF Research Database (Denmark)
Hachisuka, Toshiya; Jarosz, Wojciech; Georgiev, Iliyan
2013-01-01
scattering. Since its introduction, photon-density estimation has been significantly extended in computer graphics with the introduction of: specialized techniques that intelligently modify the positions or bandwidths to reduce visual error using a small number of photons, approaches that eliminate error...
State of the Art in Photon Density Estimation
DEFF Research Database (Denmark)
Hachisuka, Toshiya; Jarosz, Wojciech; Bouchard, Guillaume
2012-01-01
scattering. Since its introduction, photon-density estimation has been significantly extended in computer graphics with the introduction of: specialized techniques that intelligently modify the positions or bandwidths to reduce visual error using a small number of photons, approaches that eliminate error...
Time-independent inverse compton spectrum for photons from a ...
African Journals Online (AJOL)
The general theoretical aspects of inverse Compton scattering was investigated and an equation for the timeindependent inverse Compton spectrum for photons from a plasma cloud of finite extent was derived. This was done by convolving the Kompaneets equation used for describing the evolution of the photon spectrum ...
Two-photon processes in highly charged ions
Energy Technology Data Exchange (ETDEWEB)
Jahrsetz, Thorsten
2015-03-05
Two-photon processes are atomic processes in which an atom interacts simultaneously with two photons. Such processes describe a wide range of phenomena, such as two-photon decay and elastic or inelastic scattering of photons. In recent years two-photon processes involving highly charged heavy ions have become an active area of research. Such studies do not only consider the total transition or scattering rates but also their angular and polarization dependence. To support such examinations in this thesis I present a theoretical framework to describe these properties in all two-photon processes with bound initial and final states and involving heavy H-like or He-like ions. I demonstrate how this framework can be used in some detailed studies of different two-photon processes. Specifically a detailed analysis of two-photon decay of H-like and He-like ions in strong external electromagnetic fields shows the importance of considering the effect of such fields for the physics of such systems. Furthermore I studied the elastic Rayleigh as well as inelastic Raman scattering by heavy H-like ions. I found a number of previously unobserved phenomena in the angular and polarization dependence of the scattering cross-sections that do not only allow to study interesting details of the electronic structure of the ion but might also be useful for the measurement of weak physical effects in such systems.
Proton compton scattering in the resonance region
International Nuclear Information System (INIS)
Ishii, Takanobu.
1979-12-01
Differential cross sections of the proton Compton scattering have been measured in the energy range between 400 and 1150 MeV at CMS angles of 130 0 , 100 0 and 70 0 . The recoil proton was detected with a magnetic spectrometer using multi-wire proportional chambers and wire spark chambers. In coincidence with the proton, the scattered photon was detected with a lead glass Cerenkov counter of the total absorption type with a lead plate converter, and horizontal and vertical scintillation counter hodoscopes. The background due to the neutral pion photoproduction, was subtracted by using the kinematic relations between the scattered photon and the recoil proton. Theoretical calculations based on an isobar model with two components, that is, the resonance plus background, were done, and the photon couplings of the second resonance region were determined firstly from the proton Compton data. The results are that the helicity 1/2 photon couplings of P 11 (1470) and S 11 (1535), and the helicity 3/2 photon coupling of D 13 (1520) are consistent with those determined from the single pion photoproduction data, but the helicity 1/2 photon coupling of D 13 (1520) has a somewhat larger value than that from the single pion photoproduction data. (author)
Cloaking through cancellation of diffusive wave scattering
Farhat, Mohamed
2016-08-10
A new cloaking mechanism, which makes enclosed objects invisible to diffusive photon density waves, is proposed. First, diffusive scattering from a basic core-shell geometry, which represents the cloaked structure, is studied. The conditions of scattering cancellation in a quasi-static scattering regime are derived. These allow for tailoring the diffusivity constant of the shell enclosing the object so that the fields scattered from the shell and the object cancel each other. This means that the photon flow outside the cloak behaves as if the cloaked object were not present. Diffusive light invisibility may have potential applications in hiding hot spots in infrared thermography or tissue imaging. © 2016 The Author(s) Published by the Royal Society. All rights reserved.
Isospin breaking in the pion-nucleon scattering lengths
International Nuclear Information System (INIS)
Hoferichter, Martin; Kubis, Bastian; Meissner, Ulf-G.
2009-01-01
We analyze isospin breaking through quark mass differences and virtual photons in the pion-nucleon scattering lengths in all physical channels in the framework of covariant baryon chiral perturbation theory.
Isospin breaking in the pion-nucleon scattering lengths
Energy Technology Data Exchange (ETDEWEB)
Hoferichter, Martin [Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, Universitaet Bonn, D-53115 Bonn (Germany); Kubis, Bastian [Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, Universitaet Bonn, D-53115 Bonn (Germany)], E-mail: kubis@itkp.uni-bonn.de; Meissner, Ulf-G. [Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, Universitaet Bonn, D-53115 Bonn (Germany); Institut fuer Kernphysik (Theorie), Institute for Advanced Simulation, and Juelich Center for Hadron Physics, Forschungszentrum Juelich, D-52425 Juelich (Germany)
2009-07-06
We analyze isospin breaking through quark mass differences and virtual photons in the pion-nucleon scattering lengths in all physical channels in the framework of covariant baryon chiral perturbation theory.
DEFF Research Database (Denmark)
de Lasson, Jakob Rosenkrantz; Rigal, B.; Kapon, E.
We design slow and fast light photonic crystal waveguides for single-photon emission using a Bloch mode expansion and scattering matrix technique. We propose slow light designs that increase the group index-waveguide mode volume ratio for larger Purcell enhancement, and address efficient slow-to-...
International Nuclear Information System (INIS)
Valkema, R.; Blokland, J.A.K.; Papapoulos, S.E.; Bijvoet, O.L.M.; Pauwels, E.K.J.
1989-01-01
Osteoporosis is a significant health problem in the western world, with important medical, social and economical consequences. Prevention and treatment require reliable methods for in vivo monitoring of the bone mineral content (BMC) and its change in time. This paper presents an overview of currently used radiological methods, based on photon absorptiometry, and their clinical applications. With recent methods based on dual energy X-ray absorptiometry accurate and precise measurements of axial BMC can be obtained. Whether this improvements allows reliable detection of small changes in BMC remains to be investigated. (Author). 95 refs.; 1 tab
Disorder-induced resonance shifts and mode edge broadening in photonic crystal waveguides
DEFF Research Database (Denmark)
Mann, N.; Javadi, Alisa; Garcia-Fernandez, Pedro David
2014-01-01
We present theory and measurements for systematically disordered slow-light photonic crystal waveguides and find a pronounced disorder-induced blueshift and broadening of the photon density of states....
Limitations of two-level emitters as nonlinearities in two-photon controlled-PHASE gates
DEFF Research Database (Denmark)
Nysteen, Anders; McCutcheon, Dara P. S.; Heuck, Mikkel
2017-01-01
We investigate the origin of imperfections in the fidelity of a two-photon controlled-PHASE gate based on two-level-emitter nonlinearities. We focus on a passive system that operates without external modulations to enhance its performance. We demonstrate that the fidelity of the gate is limited...... by opposing requirements on the input pulse width for one-and two-photon-scattering events. For one-photon scattering, the spectral pulse width must be narrow compared with the emitter linewidth, while two-photon-scattering processes require the pulse width and emitter linewidth to be comparable. We find...
Moran, Christine H; Rycenga, Matthew; Zhang, Qiang; Xia, Younan
2011-11-10
In this work, we used surface-enhanced Raman scattering (SERS) to monitor the replacement of poly(vinyl pyrrolidone) (PVP) on Ag nanocubes by cysteamine, thiol-terminated PEG, and benzenedithiol. PVP is widely used as a colloidal stabilizer and capping agent to control the shape of Ag (as well as many other noble metals) nanocrystals during synthesis, and to stabilize the final colloidal suspension. However, the surface chemistry of Ag nanocrystals often needs to be tailored for specific applications, so the PVP coating must be removed and/or replaced by other ligands. By monitoring the signature peak from the carbonyl groups of PVP, we show, for the first time, that the PVP adsorbed on the surface of Ag nanocubes was completely replaced by the thiol molecules at room temperature over the course of a few hours. We observed the same trend no matter if the Ag nanocubes were suspended in an aqueous solution of the thiol or supported on a silicon substrate and then immersed in the thiol solution.
Vector Monte Carlo simulations on atmospheric scattering of polarization qubits.
Li, Ming; Lu, Pengfei; Yu, Zhongyuan; Yan, Lei; Chen, Zhihui; Yang, Chuanghua; Luo, Xiao
2013-03-01
In this paper, a vector Monte Carlo (MC) method is proposed to study the influence of atmospheric scattering on polarization qubits for satellite-based quantum communication. The vector MC method utilizes a transmittance method to solve the photon free path for an inhomogeneous atmosphere and random number sampling to determine whether the type of scattering is aerosol scattering or molecule scattering. Simulations are performed for downlink and uplink. The degrees and the rotations of polarization are qualitatively and quantitatively obtained, which agree well with the measured results in the previous experiments. The results show that polarization qubits are well preserved in the downlink and uplink, while the number of received single photons is less than half of the total transmitted single photons for both links. Moreover, our vector MC method can be applied for the scattering of polarized light in other inhomogeneous random media.
Characterization of a material by probability of linear scattering using effect of target thickness
International Nuclear Information System (INIS)
Nghiep, T.D.; Khai, N.T.; Cong, N.T.; Minh, D.T.N.
2013-01-01
We report on an experimental test with 662 keV gamma photons scattered from a set of samples from 6 C, 13 Al, 26 Fe, 29 Cu, 47 Ag, 82 Pb and stainless steel for determination of probability of linear scattering, which can be used for characterization of a material. The results show that for the given target and scattering angle, the effect of target thickness in gamma photons scattering relates to single and multiple scattering and that the scattered events exponentially increase with an increase in target thickness and saturation at some values of thickness. The experimental results correlate with the typical function of energy transfer model. (author)
K-shell ionization and double-ionization of Au atoms with 1.33 MeV photons
International Nuclear Information System (INIS)
Belkacem, A.; Dauvergne, D.; Feinberg, B.; Ionescu, D.; Maddi, J.; Sorensen, A.H.
2000-01-01
At relativistic energies, the cross section for the atomic photoelectric effect drops off as does the cross section for liberating any bound electron through Compton scattering. However, when the photon energy exceeds twice the rest mass of the electron, ionization may proceed via electron-positron pair creation. We used 1.33 MeV photons impinging on Au thin foils to study double K-shell ionization and vacuum-assisted photoionization. The preliminary results yield a ratio of vacuum-assisted photoionization and pair creation of 2x10 -3 , a value that is substantially higher than the ratio of photo double ionization to single photoionization that is found to be 0.5-1x10 -4 . Because of the difficulties and large error bars associated with the small cross sections additional measurements are needed to minimize systematic errors
Prompt Photons in Photoproduction at HERA
Aaron, F.D.; Alexa, C.; 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, S.; 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, X.; Jonsson, L.; Jung, A.W.; 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, M.U.; 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, I.; Soloviev, Y.; Sopicki, P.; South, D.; Spaskov, V.; Specka, A.; 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.
2010-01-01
The production of prompt photons is measured in the photoproduction regime of electron-proton scattering at HERA. The analysis is based on a data sample corresponding to a total integrated luminosity of 340 pb^-1 collected by the H1 experiment. Cross sections are measured for photons with transverse momentum and pseudorapidity in the range 6 < Et < 15 GeV and -1.0 < eta < 2.4, respectively. Cross sections for events with an additional jet are measured as a function of the transverse energy and pseudorapidity of the jet, and as a function of the fractional momenta x_gamma and x_p carried by the partons entering the hard scattering process. The correlation between the photon and the jet is also studied. The results are compared with QCD predictions based on the collinear and on the k_T factorisation approaches.
Light exiting from real photonic band gap crystals is diffuse and strongly directional
Koenderink, A.F.; Vos, Willem L.
2003-01-01
Any photonic crystal is in practice periodic with some inevitable fabricational imperfections. We have measured angle-resolved transmission of photons that are multiply scattered by this disorder in strongly photonic crystals. Peculiar non-Lambertian distributions occur as a function of frequency:
An efficient method of randomly sampling the coherent angular scatter distribution
International Nuclear Information System (INIS)
Williamson, J.F.; Morin, R.L.
1983-01-01
Monte Carlo simulations of photon transport phenomena require random selection of an interaction process at each collision site along the photon track. Possible choices are usually limited to photoelectric absorption and incoherent scatter as approximated by the Klein-Nishina distribution. A technique is described for sampling the coherent angular scatter distribution, for the benefit of workers in medical physics. (U.K.)
Photon cooperative effect in resonance spectroscopy
International Nuclear Information System (INIS)
Veklenko, B.A.
1998-01-01
A systematic method is proposed for calculating the density matrix of subsystems interacting with their environment under conditions of thermodynamic equilibrium. The density matrix of photons resonantly interacting with a surrounding gas is calculated. It is shown that use of the Gibbs distribution allows one to completely eliminate inelastic processes from the calculations. A correct account of photon-photon correlators indicates the presence of new cooperative effects. A new branch of the polariton spectrum is predicted, which is due to the presence of excited atoms in the medium. With the help of the density matrix the mean filling numbers of the photon modes are calculated. In terms of wavelengths, we have obtained a generalization of the Planck formula which accounts for photon cooperative phenomena. The manifestation of these effects in kinetic processes is discussed
Light and gas confinement in hollow-core photonic crystal fibre based photonic microcells
DEFF Research Database (Denmark)
Benabid, F.; Roberts, John; Couny, F.
2009-01-01
guides via a photonic bandgap and the other guides by virtue of an inhibited coupling between core and cladding mode constituents. For the former fibre type, we explore how the bandgap is formed using a photonic analogue of the tight-binding model and how it is related to the anti-resonant reflection...... on electromagnetically induced transparency in a rubidium filled hollow-core photonic crystal fibre, the CW-pumped hydrogen Raman laser and the generation of multi-octave spanning stimulated Raman scattering spectral combs....
Physics at high energy photon photon colliders
International Nuclear Information System (INIS)
Chanowitz, M.S.
1994-06-01
I review the physic prospects for high energy photon photon colliders, emphasizing results presented at the LBL Gamma Gamma Collider Workshop. Advantages and difficulties are reported for studies of QCD, the electroweak gauge sector, supersymmetry, and electroweak symmetry breaking
Resonance formation in photon-photon collisions
International Nuclear Information System (INIS)
Gidal, G.
1988-08-01
Recent experimental progress on resonance formation in photon-photon collisions is reviewed with particular emphasis on the pseudoscalar and tensor nonents and on the γγ* production of spin-one resonances. 37 refs., 17 figs., 5 tabs
International Nuclear Information System (INIS)
Kunwar, B.; Bhadra, A.; Gupta, S.K. Sen
2014-01-01
A preliminary, and perhaps the first, study of astrophysical applications of Delbrück scattering in a gamma-ray emitting celestial object like a gamma-ray burst (GRB) has been made. At energies≥100 MeV the elastic scattering of gamma-ray photons off the molecular dust surrounding the GRB site is dominated by Delbrück scattering. Expressions for Delbrück-scattered gamma-ray flux as a function of time has been obtained for a few selected energies by assuming a simple model of GRB. These are compared with Compton-scattered flux. At certain situations, interestingly, the former is found to exceed the latter for the first few milliseconds of the burst. The issue of detectability of Delbrück-scattered gamma-ray echo from the cloud of a GRB is discussed. Although it is observed that the detection of such an echo is not within the capability of the presently operating gamma-ray missions such as Fermi LAT, a rough estimate shows that one can be optimistic that future generation gamma-ray telescopes might be able to see such photons' contribution to the total flux. - Highlights: ► Astrophysical application of Delbrück scattering in a GRB has been made. ► Initially, the Delbrück scattering may dominate the scattering of GeV γ-rays. ► The issue of detectability of such radiations is discussed
Final-photon angular distributions in Compton double-ionization
International Nuclear Information System (INIS)
Kornberg, M.A.
1999-01-01
Angular distributions of the scattered-photon in two-electron ionization of helium by Compton scattering are reported. Our calculations are performed as a direct integration over Compton profiles. We show that backward scattering is adequately described using an uncorrelated final-state approximation, as compared with impulse approximation (IA) results. The relation dσ c 2+ /dΩ = R c dσ c + /dΩ is fulfilled within IA at high-photon energies, with R c the asymptotic shake-off ratio. (orig.)
Estimation of photon energy distribution in gamma calibration field
International Nuclear Information System (INIS)
Takahashi, Fumiaki; Shimizu, Shigeru; Yamaguchi, Yasuhiro
1997-03-01
Photon survey instruments used for radiation protection are usually calibrated at gamma radiation fields, which are traceable to the national standard with regard to exposure. Whereas scattered radiations as well as primary gamma-rays exit in the calibration field, no consideration for the effect of the scattered radiations on energy distribution is given in routine calibration works. The scattered radiations can change photon energy spectra in the field, and this can result in misinterpretations of energy-dependent instrument responses. Construction materials in the field affect the energy distribution and magnitude of the scattered radiations. The geometric relationship between a gamma source and an instrument can determine the energy distribution at the calibration point. Therefore, it is essential for the assurance of quality calibration to estimate the energy spectra at the gamma calibration fields. Then, photon energy distributions at some fields in the Facility of Radiation Standard of the Japan Atomic Energy Research Institute (JAERI) were estimated by measurements using a NaI(Tl) detector and Monte Carlo calculations. It was found that the use of collimator gives a different feature in photon energy distribution. The origin of scattered radiations and the ratio of the scattered radiations to the primary gamma-rays were obtained. The results can help to improve the calibration of photon survey instruments in the JAERI. (author)
Raman scattering in the atmospheres of the major planets
International Nuclear Information System (INIS)
Cochran, W.D.; Trafton, L.M.
1978-01-01
A method is developed for calculating the rate at which photons are Raman scattered as a function of frequency and depth in an inhomogeneous anisotropically scattering atmosphere. This method is used to determine the effects of Raman scattering by H 2 in the atmospheres of the major planets. Raman scattering causes an insufficient decrease in the blue and ultraviolet to explain the albedos of all of the planets; an additional source of extinction is necessary in this spectral region. Approximately 0.5-2.0% of the blue continuum photons have undergone Raman scattering in the shallow atmospheres of Jupiter and Saturn, while in the deep atmospheres of Uranus and Neptune Raman scattering accounts for abount 10-15% of the blue continuum intensity. The filling in of the cores of solar lines and the production of Raman-shifted ghosts of the Fraunhofer spectrum will be detectable effects in all of the major planets. Raman scattering has a significant influence on the formation and profiles of the strong red and near-infrared CH 4 bands on Uranus and Neptune. The residual intensity in the cores of these bands may be fully explained as a result of Raman scattering by H 2 . This scattering of photons into the cores of saturated absorption bands will cause an underestimate of the abundance of the absorber unless the effects of Raman scattering by H 2 in an inhomogeneous atmosphere are properly included in the analysis
On the low-energy limit of one-loop photon-graviton amplitudes
International Nuclear Information System (INIS)
Bastianelli, F.; Corradini, O.; Dávila, J.M.; Schubert, C.
2012-01-01
We present first results of a systematic study of the structure of the low-energy limit of the one-loop photon-graviton amplitudes induced by massive scalars and spinors. Our main objective is the search of KLT-type relations where effectively two photons merge into a graviton. We find such a relation at the graviton-photon-photon level. We also derive the diffeomorphism Ward identity for the 1PI one-graviton-N-photon amplitudes.
Lepton-nucleon scattering at high energies
International Nuclear Information System (INIS)
Buchmueller, W.
1993-12-01
Recent theoretical developments in the field of inelastic lepton-nucleon scattering are reviewed with emphasis on physics at HERA. Structure functions at small Bjorken-x are discussed in detail. Further topics are photoproduction of jets, the gluon densities in proton and photon, charm physics, electroweak processes and the search for new particles and interactions. (orig.)
Theorems of low energy in Compton scattering
International Nuclear Information System (INIS)
Chahine, J.
1984-01-01
We have obtained the low energy theorems in Compton scattering to third and fouth order in the frequency of the incident photon. Next we calculated the polarized cross section to third order and the unpolarized to fourth order in terms of partial amplitudes not covered by the low energy theorems, what will permit the experimental determination of these partial amplitudes. (Author) [pt
Surface Fluctuation Scattering using Grating Heterodyne Spectroscopy
DEFF Research Database (Denmark)
Edwards, R. V.; Sirohi, R. S.; Mann, J. A.
1982-01-01
Heterodyne photon spectroscopy is used for the study of the viscoelastic properties of the liquid interface by studying light scattered from thermally generated surface fluctuations. A theory of a heterodyne apparatus based on a grating is presented, and the heterodyne condition is given in terms...
Energy Technology Data Exchange (ETDEWEB)
Laveissiere, G
2001-11-01
In hadronic physics, the nucleon structure and the quarks confinement are still topical issues. The neutral pion electroproduction and virtual Compton scattering (VCS) reactions allow us to access new observables that describe this structure. This work is focussed on the VCS experiment performed at Jefferson Lab in 1998. The 4 GeV electron beam is scattered off a cryogenic hydrogen target, and the scattered electron and recoiled proton are detected in coincidence in the twin hall A spectrometers. The photon (pion) is reconstructed using a missing particle technique. The data analysis allowed to extract the cross sections relative to both process at four-momentum transfer squared Q{sup 2} = 1 GeV{sup 2}. The VCS cross section has been extracted for the first time in the proton resonance region (W between 1.O and 2.0 GeV) through the photon electroproduction reaction. Around the pion-production threshold up to the Delta(1232) resonance region, these results lead to the measurement of the generalized polarizabilities, that describe the proton structure in the same way as the elastic form factors. Moreover, the neutral pion electroproduction cross section measurement in the resonance region has brought new constraints on the existing phenomenological models. (author)
Thomson scattering measurements on an atmospheric Ar dc discharge lamp
Zhu, Xiao-Yan; Redwitz, M.; Kieft, E.R.; Sande, van de M.J.; Mullen, van der J.J.A.M.
2004-01-01
Thomson scattering (TS) experiments have been performed in the region near the electrodes of a dc powered model lamp filled with 1-2 bar argon gas. In order to suppress the false stray light and Rayleigh scattered photons, a triple grating spectrograph was used. In this way the electron density and
The complete electroweak effect and perfection of Bhabha scattering in the standard model
International Nuclear Information System (INIS)
Shi Chengye; Fang Zhenyun; Chen Xuewen
2013-01-01
In this paper, we make a close and systematic research on Bhabha scattering in the electroweak unification of the standard model (SM). In concrete research methods we make the quantum field theory of perturbation theory in a new computing mode -renormalization chain propagation theory, and do an application to the Bhabha scattering calculation research. In SM, in order to consider complete electrical weak effect about Bhabha scattering internal process, we seek out the complex renormalization mixing-loop chain propagators constituted by photon y and intermediate boson Z 0 , and then calculate the Bhabha scattering cross section about this kind of propagator by transfer complete electrical weak reaction. Within the observed errors, the calculation results are in good agreement with the experimental values. Also, the main research results not only confirm the action of the particle reaction accuracy by SM theory for describing the electrical weak effect; but also suggests the SM theory may be a per ect theory and that the theory prophecy's Higgs 'mysterious particles' (which is of particular concern in the field of academic) have the large possibility to be eventually found. (authors)
Investigation of microalgae with photon density waves
Frankovitch, Christine; Reich, Oliver; Löhmannsröben, Hans-Gerd
2007-09-01
Phototropic microalgae have a large potential for producing valuable substances for the feed, food, cosmetics, pigment, bioremediation, and pharmacy industries as well as for biotechnological processes. Today it is estimated that the microalgal aquaculture worldwide production is 5000 tons of dry matter per year (not taking into account processed products) making it an approximately $1.25 billion U.S. per year industry. For effective observation of the photosynthetic growth processes, fast on-line sensor systems that analyze the relevant biological and technical process parameters are preferred. The optical properties of the microalgae culture influence the transport of light in the photobioreactor and can be used to extract relevant information for efficient cultivation practices. Microalgae cultivation media show a combination of light absorption and scattering, which are influenced by the concentrations and the physical and chemical properties of the different absorbing and scattering species (e.g. pigments, cell components, etc.). Investigations with frequency domain photon density waves (PDW) allow for the examination of absorption and scattering properties of turbid media, namely the absorption and reduced scattering coefficient. The reduced scattering coefficient can be used to characterize physical and morphological properties of the medium, including the cell concentration, whereas the absorption coefficient correlates with the pigment content. Nannochloropsis oculata, a single-cell species of microalgae, were examined in a nutrient solution with photon density waves. The absorption and reduced scattering coefficients were experimentally determined throughout the cultivation process, and applied to gain information about the cell concentration and average cell radius.
International Nuclear Information System (INIS)
Leader, Elliot
1991-01-01
With very few unexplained results to challenge conventional ideas, physicists have to look hard to search for gaps in understanding. An area of physics which offers a lot more than meets the eye is elastic and diffractive scattering where particles either 'bounce' off each other, emerging unscathed, or just graze past, emerging relatively unscathed. The 'Blois' workshops provide a regular focus for this unspectacular, but compelling physics, attracting highly motivated devotees
Single-Photon Routing for a L-Shaped Channel
Yang, Xiong; Hou, Jiao-Jiao; Wu, Chun
2018-02-01
We have investigated the transport properties of a single photon scattered by a two-level atom embedded in a L-shaped waveguide, which is made of two one-dimensional (1D) semi-infinite coupled-resonator waveguides (CRWs). Single photons can be directed from one CRW to the other due to spontaneous emission of the atom. The result shows that the spontaneous emission of the TLS still routes single photon from one CRW to the other; the boundary existing makes the probability of finding single photon in a CRW could reach one. Our the scheme is helpful to construct a ring quantum networks.
International Nuclear Information System (INIS)
1991-02-01
The annual report on hand gives an overview of the research work carried out in the Laboratory for Neutron Scattering (LNS) of the ETH Zuerich in 1990. Using the method of neutron scattering, it is possible to examine in detail the static and dynamic properties of the condensed material. In accordance with the multidisciplined character of the method, the LNS has for years maintained a system of intensive co-operation with numerous institutes in the areas of biology, chemistry, solid-state physics, crystallography and materials research. In 1990 over 100 scientists from more than 40 research groups both at home and abroad took part in the experiments. It was again a pleasure to see the number of graduate students present, who were studying for a doctorate and who could be introduced into the neutron scattering during their stay at the LNS and thus were in the position to touch on central ways of looking at a problem in their dissertation using this modern experimental method of solid-state research. In addition to the numerous and interesting ways of formulating the questions to explain the structure, nowadays the scientific programme increasingly includes particularly topical studies in connection with high temperature-supraconductors and materials research
Friedrich, Harald
2016-01-01
This corrected and updated second edition of "Scattering Theory" presents a concise and modern coverage of the subject. In the present treatment, special attention is given to the role played by the long-range behaviour of the projectile-target interaction, and a theory is developed, which is well suited to describe near-threshold bound and continuum states in realistic binary systems such as diatomic molecules or molecular ions. It is motivated by the fact that experimental advances have shifted and broadened the scope of applications where concepts from scattering theory are used, e.g. to the field of ultracold atoms and molecules, which has been experiencing enormous growth in recent years, largely triggered by the successful realization of Bose-Einstein condensates of dilute atomic gases in 1995. The book contains sections on special topics such as near-threshold quantization, quantum reflection, Feshbach resonances and the quantum description of scattering in two dimensions. The level of abstraction is k...
Energy Technology Data Exchange (ETDEWEB)
Pratt, R.H., E-mail: rpratt@pitt.ed [Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260 (United States); LaJohn, L.A., E-mail: lal18@pitt.ed [Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260 (United States); Florescu, V., E-mail: flor@barutu.fizica.unibuc.r [Centre for Advanced Quantum Physics, University of Bucharest, MG-11 Bucharest-Magurele, 077125 Magurele (Romania); Suric, T., E-mail: suric@irb.h [R. Boskovic Institute, Bijenicka 54, 10000 Zagreb (Croatia); Chatterjee, B.K., E-mail: barun_k_chatterjee@yahoo.co [Department of Physics, Bose Institute, Kolkata 700009 (India); Roy, S.C., E-mail: suprakash.roy@gmail.co [Department of Physics, Bose Institute, Kolkata 700009 (India)
2010-02-15
We review the standard theory of Compton scattering from bound electrons, and we describe recent findings that require modification of the usual understanding, noting the nature of consequences for experiment. The subject began with Compton and scattering from free electrons. Experiment actually involved bound electrons, and this was accommodated with the use of impulse approximation (IA), which described inelastic scattering from bound electrons in terms of scattering from free electrons. This was good for the Compton peak but failed for soft final photons. The standard theory was formalized by Eisenberger and Platzman (EP) [1970. Phys. Rev. A 2, 415], whose work also suggested why impulse approximation was better than one would expect, for doubly differential cross sections (DDCS), but not for triply differential cross sections (TDCS). A relativistic version of IA (RIA) was worked out by Ribberfors [1975. Phys. Rev. B 12, 2067]. And Suric et al. [1991. Phys. Rev. Lett. 67, 189] and Bergstrom et al. [1993. Phys. Rev. A 48, 1134] developed a full relativistic second order S-matrix treatment, not making impulse approximation, but within independent particle approximation (IPA). Newer developments in the theory of Compton scattering include: (1) Demonstration that the EP estimates of the validity of IA are incorrect, although the qualitative conclusion remains unchanged; IA is not to be understood as the first term in a standard series expansion. (2) The greater validity of IA for DDCS than for the TDCS, which when integrated give DDCS, is related to the existence of a sum rule, only valid for DDCS. (3) The so-called 'asymmetry' of a Compton profile is primarily to be understood as simply the shift of the peak position in the profile; symmetric and anti-symmetric deviations from a shifted Compton profile are very small, except for high Z inner shells where further p{sup -}>.A{sup -}> effects come into play. (4) Most relativistic effects, except at low
International Nuclear Information System (INIS)
Pratt, R.H.; LaJohn, L.A.; Florescu, V.; Suric, T.; Chatterjee, B.K.; Roy, S.C.
2010-01-01
We review the standard theory of Compton scattering from bound electrons, and we describe recent findings that require modification of the usual understanding, noting the nature of consequences for experiment. The subject began with Compton and scattering from free electrons. Experiment actually involved bound electrons, and this was accommodated with the use of impulse approximation (IA), which described inelastic scattering from bound electrons in terms of scattering from free electrons. This was good for the Compton peak but failed for soft final photons. The standard theory was formalized by Eisenberger and Platzman (EP) [1970. Phys. Rev. A 2, 415], whose work also suggested why impulse approximation was better than one would expect, for doubly differential cross sections (DDCS), but not for triply differential cross sections (TDCS). A relativistic version of IA (RIA) was worked out by Ribberfors [1975. Phys. Rev. B 12, 2067]. And Suric et al. [1991. Phys. Rev. Lett. 67, 189] and Bergstrom et al. [1993. Phys. Rev. A 48, 1134] developed a full relativistic second order S-matrix treatment, not making impulse approximation, but within independent particle approximation (IPA). Newer developments in the theory of Compton scattering include: (1) Demonstration that the EP estimates of the validity of IA are incorrect, although the qualitative conclusion remains unchanged; IA is not to be understood as the first term in a standard series expansion. (2) The greater validity of IA for DDCS than for the TDCS, which when integrated give DDCS, is related to the existence of a sum rule, only valid for DDCS. (3) The so-called 'asymmetry' of a Compton profile is primarily to be understood as simply the shift of the peak position in the profile; symmetric and anti-symmetric deviations from a shifted Compton profile are very small, except for high Z inner shells where further p → .A → effects come into play. (4) Most relativistic effects, except at low energies, are to be
Compton scatter correction for planner scintigraphic imaging
Energy Technology Data Exchange (ETDEWEB)
Vaan Steelandt, E; Dobbeleir, A; Vanregemorter, J [Algemeen Ziekenhuis Middelheim, Antwerp (Belgium). Dept. of Nuclear Medicine and Radiotherapy
1995-12-01
A major problem in nuclear medicine is the image degradation due to Compton scatter in the patient. Photons emitted by the radioactive tracer scatter in collision with electrons of the surrounding tissue. Due to the resulting loss of energy and change in direction, the scattered photons induce an object dependant background on the images. This results in a degradation of the contrast of warm and cold lesions. Although theoretically interesting, most of the techniques proposed in literature like the use of symmetrical photopeaks can not be implemented on the commonly used gamma camera due to the energy/linearity/sensitivity corrections applied in the detector. A method for a single energy isotope based on existing methods with adjustments towards daily practice and clinical situations is proposed. It is assumed that the scatter image, recorded from photons collected within a scatter window adjacent to the photo peak, is a reasonable close approximation of the true scatter component of the image reconstructed from the photo peak window. A fraction `k` of the image using the scatter window is subtracted from the image recorded in the photo peak window to produce the compensated image. The principal matter of the method is the right value for the factor `k`, which is determined in a mathematical way and confirmed by experiments. To determine `k`, different kinds of scatter media are used and are positioned in different ways in order to simulate a clinical situation. For a secondary energy window from 100 to 124 keV below a photo peak window from 126 to 154 keV, a value of 0.7 is found. This value has been verified using both an antropomorph thyroid phantom and the Rollo contrast phantom.
International Nuclear Information System (INIS)
Diziain, S.; Bijeon, J.-L.; Adam, P.-M.; Lamy de la Chapelle, M.; Thomas, B.; Deturche, R.; Royer, P.
2007-01-01
An apertureless scanning near-field optical microscope (ASNOM) in reflection backscattering configuration is designed to conduct spectroscopic experiments on opaque samples constituted of latex beads. The ASNOM proposed takes advantage of the depth-discrimination properties of confocal microscopes to efficiently extract the near-field optical signal. Given their importance in a spectroscopic experiment, we systematically compare the lock-in and synchronous photon counting detection methods. Some results of Rayleigh's scattering in the near field of the test samples are used to illustrate the possibilities of this technique for reflection backscattering spectroscopy
Energy Technology Data Exchange (ETDEWEB)
Diziain, S. [Institut Charles Delaunay, CNRS FRE 2848, Laboratoire de Nanotechnologie et d' Instrumentation Optique, Universite de technologie de Troyes, 12 rue Marie Curie, BP 2060, 10010 Troyes cedex (France); Bijeon, J.-L. [Institut Charles Delaunay, CNRS FRE 2848, Laboratoire de Nanotechnologie et d' Instrumentation Optique, Universite de technologie de Troyes, 12 rue Marie Curie, BP 2060, 10010 Troyes cedex (France)]. E-mail: bijeon@utt.fr; Adam, P.-M. [Institut Charles Delaunay, CNRS FRE 2848, Laboratoire de Nanotechnologie et d' Instrumentation Optique, Universite de technologie de Troyes, 12 rue Marie Curie, BP 2060, 10010 Troyes cedex (France); Lamy de la Chapelle, M. [Institut Charles Delaunay, CNRS FRE 2848, Laboratoire de Nanotechnologie et d' Instrumentation Optique, Universite de technologie de Troyes, 12 rue Marie Curie, BP 2060, 10010 Troyes cedex (France); Thomas, B. [Institut Charles Delaunay, CNRS FRE 2848, Laboratoire de Nanotechnologie et d' Instrumentation Optique, Universite de technologie de Troyes, 12 rue Marie Curie, BP 2060, 10010 Troyes cedex (France); Deturche, R. [Institut Charles Delaunay, CNRS FRE 2848, Laboratoire de Nanotechnologie et d' Instrumentation Optique, Universite de technologie de Troyes, 12 rue Marie Curie, BP 2060, 10010 Troyes cedex (France); Royer, P. [Institut Charles Delaunay, CNRS FRE 2848, Laboratoire de Nanotechnologie et d' Instrumentation Optique, Universite de technologie de Troyes, 12 rue Marie Curie, BP 2060, 10010 Troyes cedex (France)
2007-01-15
An apertureless scanning near-field optical microscope (ASNOM) in reflection backscattering configuration is designed to conduct spectroscopic experiments on opaque samples constituted of latex beads. The ASNOM proposed takes advantage of the depth-discrimination properties of confocal microscopes to efficiently extract the near-field optical signal. Given their importance in a spectroscopic experiment, we systematically compare the lock-in and synchronous photon counting detection methods. Some results of Rayleigh's scattering in the near field of the test samples are used to illustrate the possibilities of this technique for reflection backscattering spectroscopy.
Holographic photon production in heavy ion collisions
International Nuclear Information System (INIS)
Iatrakis, Ioannis; Kiritsis, Elias; Shen, Chun; Yang, Di-Lun
2017-01-01
The thermal-photon emission from strongly coupled gauge theories at finite temperature is calculated using holographic models for QCD in the Veneziano limit (V-QCD). The emission rates are then embedded in hydrodynamic simulations combined with prompt photons from hard scattering and the thermal photons from hadron gas to analyze the spectra and anisotropic flow of direct photons at RHIC and LHC. The results from different sources responsible for the thermal photons in QGP including the weakly coupled QGP (wQGP) from perturbative calculations, strongly coupled N=4 super Yang-Mills (SYM) plasma (as a benchmark for reference), and Gubser’s phenomenological holographic model are then compared. It is found that the direct-photon spectra are enhanced in the strongly coupled scenario compared with the ones in the wQGP, especially at high momenta. Moreover, both the elliptic flow and triangular flow of direct photons are amplified at high momenta for V-QCD and the SYM plasma. The results are further compared with experimental observations.
Holographic photon production in heavy ion collisions
Energy Technology Data Exchange (ETDEWEB)
Iatrakis, Ioannis [Institute for Theoretical Physics and Center for Extreme Matter and Emergent Phenomena,Utrecht University,Leuvenlaan 4, 3584 CE Utrecht (Netherlands); Kiritsis, Elias [Crete Center for Theoretical Physics, Institute of Theoretical and Computational Physics,Department of Physics, University of Crete,71003 Heraklion (Greece); Crete Center for Quantum Complexity and Nanotechnology,Department of Physics, University of Crete,71003 Heraklion (Greece); APC, Univ Paris Diderot, Sorbonne Paris Cité, APC, UMR 7164 CNRS,F-75205 Paris (France); Shen, Chun [Department of Physics, McGill University,3600 University Street, Montreal, QC, H3A 2T8 (Canada); Yang, Di-Lun [Theoretical Research Division, Nishina Center, RIKEN, Wako,Saitama 351-0198 (Japan)
2017-04-07
The thermal-photon emission from strongly coupled gauge theories at finite temperature is calculated using holographic models for QCD in the Veneziano limit (V-QCD). The emission rates are then embedded in hydrodynamic simulations combined with prompt photons from hard scattering and the thermal photons from hadron gas to analyze the spectra and anisotropic flow of direct photons at RHIC and LHC. The results from different sources responsible for the thermal photons in QGP including the weakly coupled QGP (wQGP) from perturbative calculations, strongly coupled N=4 super Yang-Mills (SYM) plasma (as a benchmark for reference), and Gubser’s phenomenological holographic model are then compared. It is found that the direct-photon spectra are enhanced in the strongly coupled scenario compared with the ones in the wQGP, especially at high momenta. Moreover, both the elliptic flow and triangular flow of direct photons are amplified at high momenta for V-QCD and the SYM plasma. The results are further compared with experimental observations.
Calculating Rayleigh scattering amplitudes from 100 eV to 10 MeV
International Nuclear Information System (INIS)
Parker, J.C.; Reynaud, G.W.; Botto, D.J.; Pratt, R.H.
1979-01-01
An attempt is made to explain how to calculate the contribution to elastic photon-atom scattering due to Rayleigh scattering (the scattering off bound electrons) in the photon energy range 100 eV less than or equal to W less than or equal to 10 MeV. All intermediate calculations are described, including the calculation of the potential, bound state wave functions, matrix elements, and final cross sections. 12 references
International Nuclear Information System (INIS)
Singh, Gurvinderjit; Singh, Manpreet; Singh, Bhajan; Sandhu, B.S.
2006-01-01
The gamma photons continue to soften in energy as the number of scatterings increases in the sample having finite dimensions both in depth and lateral dimensions. The number of multiply scattered photons increases with an increase in target thickness and saturates at a particular value of the target thickness known as saturation depth. The present experiment is undertaken to study the effect of atomic number of the target on saturation depth of 0.662 MeV incident gamma photons multiply scattered from targets of various thicknesses. The scattered photons are detected by an HPGe gamma detector placed at 90 o to the incident beam direction. We observe that with an increase in target thickness, the number of multiply scattered photons also increases and saturates at a particular value of the target thickness. The saturation depth decreases with increasing atomic number. The double Compton scattered peak is also observed in the experimental spectra
Compton scatter tomography in TOF-PET
Hemmati, Hamidreza; Kamali-Asl, Alireza; Ay, Mohammadreza; Ghafarian, Pardis
2017-10-01
Scatter coincidences contain hidden information about the activity distribution on the positron emission tomography (PET) imaging system. However, in conventional reconstruction, the scattered data cause the blurring of images and thus are estimated and subtracted from detected coincidences. List mode format provides a new aspect to use time of flight (TOF) and energy information of each coincidence in the reconstruction process. In this study, a novel approach is proposed to reconstruct activity distribution using the scattered data in the PET system. For each single scattering coincidence, a scattering angle can be determined by the recorded energy of the detected photons, and then possible locations of scattering can be calculated based on the scattering angle. Geometry equations show that these sites lie on two arcs in 2D mode or the surface of a prolate spheroid in 3D mode, passing through the pair of detector elements. The proposed method uses a novel and flexible technique to estimate source origin locations from the possible scattering locations, using the TOF information. Evaluations were based on a Monte-Carlo simulation of uniform and non-uniform phantoms at different resolutions of time and detector energy. The results show that although the energy uncertainties deteriorate the image spatial resolution in the proposed method, the time resolution has more impact on image quality than the energy resolution. With progress of the TOF system, the reconstruction using the scattered data can be used in a complementary manner, or to improve image quality in the next generation of PET systems.
Resonant x-ray Raman scattering from atoms and molecules
International Nuclear Information System (INIS)
Cowan, P.L.
1992-01-01
Inelastic x-ray scattering and elastic x-ray scattering are fundamentally related processes. When the x-ray photon energy is near the ionization threshold for an inner shell, the inelastic channel is dominated by resonant x-ray Raman scattering. Studies of this emission not only illuminate the resonant scattering process in general, they also point to new opportunities for spectral studies of electronic structure using x-rays. Atoms in the form of a free gas provide an ideal target for testing the current theoretical understanding of resonant x-ray Raman scattering. In addition, x-ray scattering from molecular gases demonstrates the effect of bonding symmetry on the polarization and angular distribution of the scattered x-rays. Comparisons of experimental data with theory demonstrate both the successes and limitations of simple, single-electron interpretations of the scattering process
Deciphering the quark-gluon structure of the photon in electronγ collisions
International Nuclear Information System (INIS)
Eboli, O.J.P.; Gonzalez-Garcia, M.C.; Halzen, F.; Novaes, S.F.
1992-11-01
The capability of an electron γ collider to unravel the hadronic content of the photon is investigated. The experimental problem for probing the gluonic structure of the photon is that small-x triggers overwhelmingly select soft photons rather than soft gluons in hard photons. It is showed that the problem can be finessed in experiments where laser back-scattering is used to prepare a source of very hard photons. It is illustrated their power for studying the parton distribution of the photon and, specifically, for separating the quark and gluon components in events where dijets, jet-γ pairs, and heavy quark pairs are produced. (author)
The hadronic component of the photon structure function F2γ(Q2, x)
International Nuclear Information System (INIS)
Gotsman, E.
1988-01-01
The quality of the high Q 2 data presently available in photon-photon scattering, is not sufficient to allow for a unique determination of the QCD parameter Λ (as it is strongly correlated with the hadronic component of the photon). The authors show that a combination of the QPM point-like cross section and a hadronic cross section given by a simple power expansion in energy, provides a good description of the experimental photon structure function and photon-photon total cross section
Slow-light effects in photonic crystal membrane lasers
DEFF Research Database (Denmark)
Xue, Weiqi; Yu, Yi; Ottaviano, Luisa
2015-01-01
In this paper, we present a systematic investigation of photonic crystal cavity laser operating in the slow-light regime. The dependence of lasing threshold on the effect of slow-light will be particularly highlighted.......In this paper, we present a systematic investigation of photonic crystal cavity laser operating in the slow-light regime. The dependence of lasing threshold on the effect of slow-light will be particularly highlighted....
De Wolf, E.A.
2002-01-01
We discuss basic concepts and properties of diffractive phenomena in soft hadron collisions and in deep-inelastic scattering at low Bjorken-x. The paper is not a review of the rapidly developing field but presents an attempt to show in simple terms the close inter-relationship between the dynamics of high-energy hadronic and deep-inelastic diffraction. Using the saturation model of Golec-Biernat and Wusthoff as an example, a simple explanation of geometrical scaling is presented. The relation between the QCD anomalous multiplicity dimension and the Pomeron intercept is discussed.
International Nuclear Information System (INIS)
Wolf, E.A. de
2002-01-01
We discuss basic concepts and properties of diffractive phenomena in soft hadron collisions and in deep-inelastic scattering at low Bjorken - x. The paper is not a review of the rapidly developing field but presents an attempt to show in simple terms the close inter-relationship between the dynamics of high-energy hadronic and deep-inelastic diffraction. Using the saturation model of Golec-Biernat and Wuesthoff as an example, a simple explanation of geometrical scaling is presented. The relation between the QCD anomalous multiplicity dimension and the Pomeron intercept is discussed. (author)
Bose-Einstein condensation of photons in a 'white-wall' photon box
International Nuclear Information System (INIS)
Klaers, Jan; Schmitt, Julian; Vewinger, Frank; Weitz, Martin
2011-01-01
Bose-Einstein condensation, the macroscopic ground state occupation of a system of bosonic particles below a critical temperature, has been observed in cold atomic gases and solid-state physics quasiparticles. In contrast, photons do not show this phase transition usually, because in Planck's blackbody radiation the particle number is not conserved and at low temperature the photons disappear in the walls of the system. Here we report on the realization of a photon Bose-Einstein condensate in a dye-filled optical microcavity, which acts as a 'white-wall' photon box. The cavity mirrors provide a trapping potential and a non-vanishing effective photon mass, making the system formally equivalent to a two-dimensional gas of trapped massive bosons. Thermalization of the photon gas is reached in a number conserving way by multiple scattering off the dye molecules. Signatures for a BEC upon increased photon density are: a spectral distribution that shows Bose-Einstein distributed photon energies with a macroscopically populated peak on top of a broad thermal wing, the observed threshold of the phase transition showing the predicted absolute value and scaling with resonator geometry, and condensation appearing at the trap centre even for a spatially displaced pump spot.
Bose-Einstein condensation of photons in a 'white-wall' photon box
Klärs, Jan; Schmitt, Julian; Vewinger, Frank; Weitz, Martin
2011-01-01
Bose-Einstein condensation, the macroscopic ground state occupation of a system of bosonic particles below a critical temperature, has been observed in cold atomic gases and solid-state physics quasiparticles. In contrast, photons do not show this phase transition usually, because in Planck's blackbody radiation the particle number is not conserved and at low temperature the photons disappear in the walls of the system. Here we report on the realization of a photon Bose-Einstein condensate in a dye-filled optical microcavity, which acts as a "white-wall" photon box. The cavity mirrors provide a trapping potential and a non-vanishing effective photon mass, making the system formally equivalent to a two-dimensional gas of trapped massive bosons. Thermalization of the photon gas is reached in a number conserving way by multiple scattering off the dye molecules. Signatures for a BEC upon increased photon density are: a spectral distribution that shows Bose-Einstein distributed photon energies with a macroscopically populated peak on top of a broad thermal wing, the observed threshold of the phase transition showing the predicted absolute value and scaling with resonator geometry, and condensation appearing at the trap centre even for a spatially displaced pump spot.
Photon-photon collisions and photon structure functions at LEP
Patt, J
2000-01-01
The present knowledge of the structure of the photon based on measurements of photon structure functions is discussed. This review covers recent results on QED structure functions and on the hadronic structure function F/sub 2//sup gamma /. (13 refs).
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.
Photonic Crystals Towards Nanoscale Photonic Devices
Lourtioz, Jean-Michel; Berger, Vincent; Gérard, Jean-Michel; Maystre, Daniel; Tchelnokov, Alexei; Pagnoux, Dominique
2008-01-01
Just like the periodical crystalline potential in solid state crystals determines their properties for the conduction of electrons, the periodical structuring of photonic crystals leads to envisioning the possibility of achieving a control of the photon flux in dielectric and metallic materials. The use of photonic crystals as cages for storing, filtering or guiding light at the wavelength scale paves the way to the realization of optical and optoelectronic devices with ultimate properties and dimensions. This will contribute towards meeting the demands for greater miniaturization imposed by the processing of an ever increasing number of data. Photonic Crystals will provide students and researchers from different fields with the theoretical background required for modelling photonic crystals and their optical properties, while at the same time presenting the large variety of devices, ranging from optics to microwaves, where photonic crystals have found application. As such, it aims at building bridges between...
Photonic Crystals Towards Nanoscale Photonic Devices
Lourtioz, Jean-Michel; Berger, Vincent; Gérard, Jean-Michel; Maystre, Daniel; Tchelnokov, Alexis
2005-01-01
Just like the periodical crystalline potential in solid-state crystals determines their properties for the conduction of electrons, the periodical structuring of photonic crystals leads to envisioning the possibility of achieving a control of the photon flux in dielectric and metallic materials. The use of photonic crystals as a cage for storing, filtering or guiding light at the wavelength scale thus paves the way to the realisation of optical and optoelectronic devices with ultimate properties and dimensions. This should contribute toward meeting the demands for a greater miniaturisation that the processing of an ever increasing number of data requires. Photonic Crystals intends at providing students and researchers from different fields with the theoretical background needed for modelling photonic crystals and their optical properties, while at the same time presenting the large variety of devices, from optics to microwaves, where photonic crystals have found applications. As such, it aims at building brid...
International Nuclear Information System (INIS)
Jadach, S.; Richter-Was, E.; Ward, B.F.L.; Was, Z.
1991-01-01
Starting from an earlier benchmark analytical calculation of the luminosity process e + e-→e + e-+(γ) at the SLAC Linear Collider (SLC) and the CERN e + e- collider LEP, we use the methods of Yennie, Frautschi, and Suura to develop an analytical improved naive exponentiated formula for this process. The formula is compared to our multiple-photon Monte Carlo event generator BHLUMI (1.13) for the same process. We find agreement on the overall cross-section normalization between the exponentiated formula and BHLUMI below the 0.2% level. In this way, we obtain an important cross-check on the normalization of our higher-order results in BHLUMI and we arrive at formulas which represent the LEP/SLC luminosity process in the below 1% Z 0 physics tests of the SU(2) L xU(1) theory in complete analogy with the famous high-precision Z 0 line-shape formulas for the e + e-→μ + μ - process discussed by Berends et al., for example
Coherence effects in radiative scattering
International Nuclear Information System (INIS)
Knoll, J.; Lenk, R.
1993-03-01
The bremsstrahl-production of photons in dense matter is reinvestigated using the example of an exactly solvable quantum mechanical model in one space dimension. Coherence phenomena between successive radiative scatterings among the constituents lead to a modification of the production cross section in the medium relative to the incoherent quasi-free prescription used in kinetic models. Analytic expressions for the correction factor have been derived comparing the quantum rates with the corresponding incoherent quasi-free rates. The result has implications for the kinetic description of all kinds of radiative processes in nucleus-nucleus collisions, both on the level of hadron and parton dynamics. (orig.)
International Nuclear Information System (INIS)
Alberico, W.M.; Molinari, A.
1982-01-01
In this paper we briefly review the formalism of the nuclear Compton scattering in the frame of the low-energy theorems (LET). We treat the resonant terms of the amplitude, having collective intermediate nuclear states, as a superposition of Lorentz lines with energy, width and strength fixed by the photo-absorption experiments. The gauge terms are evaluated starting from a simple, but realistic, nuclear Hamiltonian. Dynamical nucleon-nucleon correlations are consistently taken into account, beyond those imposed by the Pauli principle. The comparison of the theoretical predictions with the data of elastic diffusion of photons from 208 Pb shows that LET are insufficient to account for the experiment. (orig.)
Photon and photon reactions: elementary theoretical introduction
International Nuclear Information System (INIS)
Diu, B.
The electromagnetic field and associated quanta, the photons, are simply and briefly studied. The conventional electromagnetism laws are recalled. Fundamental concepts such as gauge invariance, the electromagnetic current conservation, and photon behavior against the internal symmetries of strong interactions are simply introduced. Results and notations are applied to analysis of reactions where photons intervene in initial or final states (photoproduction) within the limits of amplitude properties in the conventional space-time. The helicity and invariant amplitude formalisms are compared [fr
Photon interactions with nuclei
International Nuclear Information System (INIS)
Thornton, S.T.; Sealock, R.M.
1989-01-01
This document is a progress report for DOE Grant No. FG05-89ER40501, A000. The grant began March, 1989. Our primary research effort has been expended at the LEGS project at Brookhaven National Laboratory. This report will summarize our present research effort at LEGS as well as data analysis and publications from previous experiments performed at SLAC. In addition the principal investigators are heavily involved in the CLAS collaboration in Hall B at CEBAF. We have submitted several letters of intent and proposals and have made commitments to construct experimental equipment for CEBAF. We expect our primary experimental effort to continue at LEGS until CEBAF becomes operational. This report will be divided into separate sections describing our progress at LEGS, SLAC, and CEBAF. We will also discuss our significant efforts in the education and training of both undergraduate and graduate students. Photon detectors are described as well as experiments on delta deformation in nuclei of quasielastic scattering and excitation of the delta by 4 He(e,e')
Review and history of photon cross section calculations
Energy Technology Data Exchange (ETDEWEB)
Hubbell, J H [National Institute of Standards and Technology, Ionizing Radiation Division, Mail Stop 8463, 100 Bureau Drive, Gaithersburg, MD 20899-8463 (United States)
2006-07-07
Photon (x-ray, gamma-ray, bremsstrahlung) mass attenuation coefficients, {mu}/{rho}, are among the most widely used physical parameters employed in medical diagnostic and therapy computations, as well as in diverse applications in other fields such as nuclear power plant shielding, health physics and industrial irradiation and monitoring, and in x-ray crystallography. This review traces the evolution of this data base from its empirical beginnings totally derived from measurements beginning in 1907 by Barkla and Sadler and continuing up through the 1935 Allen compilation (published virtually unchanged in all editions up through 1971-1972 of the Chemical Rubber Handbook), to the 1949 semi-empirical compilation of Victoreen, as our theoretical understanding of the constituent Compton scattering, photoabsorption and pair production interactions of photons with atoms became more quantitative. The 1950s saw the advent of completely theoretical (guided by available measured data) systematic compilations such as in the works of Davisson and Evans, and by White-Grodstein under the direction of Fano, using mostly theory developed in the 1930s (pre-World War II) by Sauter, Bethe, Heitler and others. Post-World War II new theoretical activity, and the introduction of the electronic automatic computer, led to the more extensive and more accurate compilations in the 1960s and 1970s by Storm and Israel, and by Berger and Hubbell. Today's {mu}/{rho} compilations by Cullen et al, by Seltzer, Berger and Hubbell, and by others, collectively spanning the ten decades of photon energy from 10 eV to 100 GeV, for all elements Z= 1 to 100, draw heavily on the 1970s shell-by-shell photoabsorption computations of Scofield, the 1960s coherent and incoherent scattering computations of Cromer et al, and the 1980 computations of electron-positron pair and triplet computations of Hubbell, Gimm and Oeverboe, these names being representative of the vast legions of other researchers whose work
REVIEW: Review and history of photon cross section calculations
Hubbell, J. H.
2006-07-01
Photon (x-ray, gamma-ray, bremsstrahlung) mass attenuation coefficients, μ/ρ, are among the most widely used physical parameters employed in medical diagnostic and therapy computations, as well as in diverse applications in other fields such as nuclear power plant shielding, health physics and industrial irradiation and monitoring, and in x-ray crystallography. This review traces the evolution of this data base from its empirical beginnings totally derived from measurements beginning in 1907 by Barkla and Sadler and continuing up through the 1935 Allen compilation (published virtually unchanged in all editions up through 1971-1972 of the Chemical Rubber Handbook), to the 1949 semi-empirical compilation of Victoreen, as our theoretical understanding of the constituent Compton scattering, photoabsorption and pair production interactions of photons with atoms became more quantitative. The 1950s saw the advent of completely theoretical (guided by available measured data) systematic compilations such as in the works of Davisson and Evans, and by White-Grodstein under the direction of Fano, using mostly theory developed in the 1930s (pre-World War II) by Sauter, Bethe, Heitler and others. Post-World War II new theoretical activity, and the introduction of the electronic automatic computer, led to the more extensive and more accurate compilations in the 1960s and 1970s by Storm and Israel, and by Berger and Hubbell. Today's μ/ρ compilations by Cullen et al, by Seltzer, Berger and Hubbell, and by others, collectively spanning the ten decades of photon energy from 10 eV to 100 GeV, for all elements Z= 1 to 100, draw heavily on the 1970s shell-by-shell photoabsorption computations of Scofield, the 1960s coherent and incoherent scattering computations of Cromer et al, and the 1980 computations of electron-positron pair and triplet computations of Hubbell, Gimm and Øverbø, these names being representative of the vast legions of other researchers whose work fed into these
Certain theories of multiple scattering in random media of discrete scatterers
International Nuclear Information System (INIS)
Olsen, R.L.; Kharadly, M.M.Z.; Corr, D.G.
1976-01-01
New information is presented on the accuracy of the heuristic approximations in two important theories of multiple scattering in random media of discrete scatterers: Twersky's ''free-space'' and ''two-space scatterer'' formalisms. Two complementary approaches, based primarily on a one-dimensional model and the one-dimensional forms of the theories, are used. For scatterer distributions of low average density, the ''heuristic'' asymptotic forms for the coherent field and the incoherent intensity are compared with asymptotic forms derived from a systematic analysis of the multiple scattering processes. For distributions of higher density, both in the average number of scatterers per wavelength and in the degree of packing of finite-size scatterers, the analysis is carried out ''experimentally'' by means of a Monte Carlo computer simulation. Approximate series expressions based on the systematic approach are numerically evaluated along with the heuristic expressions. The comparison (for both forward- and back-scattered field moments) is made for the worst-case conditions of strong multiple scattering for which the theories have not previously been evaluated. Several significant conclusions are drawn which have certain practical implications: in application of the theories to describe some of the scattering phenomena which occur in the troposphere, and in the further evaluation of the theories using experiments on physical models