Deconvolution of shift-variant broadening for Compton scatter imaging

International Nuclear Information System (INIS)

Evans, Brian L.; Martin, Jeffrey B.; Roggemann, Michael C.

1999-01-01

A technique is presented for deconvolving shift-variant Doppler broadening of singly Compton scattered gamma rays from their recorded energy distribution. Doppler broadening is important in Compton scatter imaging techniques employing gamma rays with energies below roughly 100 keV. The deconvolution unfolds an approximation to the angular distribution of scattered photons from their recorded energy distribution in the presence of statistical noise and background counts. Two unfolding methods are presented, one based on a least-squares algorithm and one based on a maximum likelihood algorithm. Angular distributions unfolded from measurements made on small scattering targets show less evidence of Compton broadening. This deconvolution is shown to improve the quality of filtered backprojection images in multiplexed Compton scatter tomography. Improved sharpness and contrast are evident in the images constructed from unfolded signals

Compton scattering

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

Compton scattering

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.

Deeply virtual compton scattering on a virtual pion target

International Nuclear Information System (INIS)

Amrath, D.; Diehl, M.; Lansberg, J.P.; Heidelberg Univ.

2008-07-01

We study deeply virtual Compton scattering on a virtual pion that is emitted by a proton. Using a range of models for the generalized parton distributions of the pion, we evaluate the cross section, as well as the beam spin and beam charge asymmetries in the leading-twist approximation. Studying Compton scattering on the pion in suitable kinematics puts high demands on both beam energy and luminosity, and we find that the corresponding requirements will first be met after the energy upgrade at Jefferson Laboratory. As a by-product of our study, we construct a parameterization of pion generalized parton distributions that has a non-trivial interplay between the x and t dependence and is in good agreement with form factor data and lattice calculations. (orig.)

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

Forward Compton scattering with weak neutral current: Constraints from sum rules

Directory of Open Access Journals (Sweden)

Mikhail Gorchtein

2015-07-01

Full Text Available We generalize forward real Compton amplitude to the case of the interference of the electromagnetic and weak neutral current, formulate a low-energy theorem, relate the new amplitudes to the interference structure functions and obtain a new set of sum rules. We address a possible new sum rule that relates the product of the axial charge and magnetic moment of the nucleon to the 0th moment of the structure function g5(ν,0. For the dispersive γZ-box correction to the proton's weak charge, the application of the GDH sum rule allows us to reduce the uncertainty due to resonance contributions by a factor of two. The finite energy sum rule helps addressing the uncertainty in that calculation due to possible duality violations.

Virtual compton scattering off protons at moderately large momentum transfer

International Nuclear Information System (INIS)

Kroll, P.; Schuermann, M.; Guichon, P.A.M.

1995-01-01

The amplitudes for virtual Compton scattering off protons are calculated within the framework of the diquark model in which protons are viewed as being built up by quarks and diquarks. The latter objects are treated as quasi-elementary constituents of the proton. Virtual Compton scattering, electroproduction of photons and the Bethe-Heitler contamination are discussed for various kinematical situations. We particularly emphasize the role of the electron asymmetry for measuring the relative phases between the virtual Compton and the Bethe-Heitler amplitudes. It is also shown that the model is able to describe very well the experimental data for real Compton scattering off protons. (authors). 35 refs., 8 figs., 1 tab

Virtual compton scattering off protons at moderately large momentum transfer

Energy Technology Data Exchange (ETDEWEB)

Kroll, P; Schuermann, M [Wuppertal Univ. (Gesamthochschule) (Germany); Guichon, P A.M. [CEA Centre d` Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. d` Astrophysique, de la Physique des Particules, de la Physique Nucleaire et de l` Instrumentation Associee

1995-06-28

The amplitudes for virtual Compton scattering off protons are calculated within the framework of the diquark model in which protons are viewed as being built up by quarks and diquarks. The latter objects are treated as quasi-elementary constituents of the proton. Virtual Compton scattering, electroproduction of photons and the Bethe-Heitler contamination are discussed for various kinematical situations. We particularly emphasize the role of the electron asymmetry for measuring the relative phases between the virtual Compton and the Bethe-Heitler amplitudes. It is also shown that the model is able to describe very well the experimental data for real Compton scattering off protons. (authors). 35 refs., 8 figs., 1 tab.

Virtual Compton scattering off protons at moderately large momentum transfer

International Nuclear Information System (INIS)

Kroll, P.

1996-01-01

The amplitudes for virtual Compton scattering off protons are calculated within the framework of the diquark model in which protons are viewed as being built up by quarks and diquarks. The latter objects are treated as quasi-elementary constituents of the proton. Virtual Compton scattering, electroproduction off protons and the Bethe-Heitler contamination are photon discussed for various kinematical situations. We particularly emphasize the role of the electron asymmetry for measuring the relative phases between the virtual Compton and the Bethe-Heitler amplitudes. It is also shown that the model is able to describe very well the experimental data for real Compton scattering off protons. (orig.)

Testing special relativity theory using Compton scattering

International Nuclear Information System (INIS)

Contreras S, H.; Hernandez A, L.; Baltazar R, A.; Escareno J, E.; Mares E, C. A.; Hernandez V, C.; Vega C, H. R.

2010-10-01

The validity of the special relativity theory has been tested using the Compton scattering. Since 1905 several experiments has been carried out to show that time, mass, and length change with the velocity, in this work the Compton scattering has been utilized as a simple way to show the validity to relativity. The work was carried out through Monte Carlo calculations and experiments with different gamma-ray sources and a gamma-ray spectrometer with a 3 x 3 NaI (Tl) detector. The pulse-height spectra were collected and the Compton edge was observed. This information was utilized to determine the relationship between the electron's mass and energy using the Compton -knee- position, the obtained results were contrasted with two collision models between photon and electron, one model was built using the classical physics and another using the special relativity theory. It was found that calculations and experiments results fit to collision model made using the special relativity. (Author)

Compton scattering at high intensities

Energy Technology Data Exchange (ETDEWEB)

Heinzl, Thomas, E-mail: thomas.heinzl@plymouth.ac.u [University of Plymouth, School of Mathematics and Statistics, Drake Circus, Plymouth PL4 8AA (United Kingdom)

2009-12-01

High-intensity Compton scattering takes place when an electron beam is brought into collision with a high power laser. We briefly review the main intensity signatures using the formalism of strong-field quantum electrodynamics.

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

Nucleon structure study by virtual compton scattering

International Nuclear Information System (INIS)

Berthot, J.; Bertin, P.Y.; Breton, V.; Fonvielle, H.; Hyde-Wright, C.; Quemener, G.; Ravel, O.; Braghieri, A.; Pedroni, P.; Boeglin, W.U.; Boehm, R.; Distler, M.; Edelhoff, R.; Friedrich, J.; Geiges, R.; Jennewein, P.; Kahrau, M.; Korn, M.; Kramer, H.; Krygier, K.W.; Kunde, V.; Liesenfeld, A.; Merle, K.; Neuhausen, R.; Offermann, E.A.J.M.; Pospischil, T.; Rosner, G.; Sauer, P.; Schmieden, H.; Schardt, S.; Tamas, G.; Wagner, A.; Walcher, T.; Wolf, S.

1995-01-01

We propose to study nucleon structure by Virtual Compton Scattering using the reaction p(e,e'p)γ with the MAMI facility. We will detect the scattered electron and the recoil proton in coincidence in the high resolution spectrometers of the hall A1. Compton events will be separated from the other channels (principally π 0 production) by missing-mass reconstruction. We plan to investigate this reaction near threshold. Our goal is to measure new electromagnetic observables which generalize the usual magnetic and electric polarizabilities. (authors). 9 refs., 18 figs., 7 tabs

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.

Deeply virtual compton scattering at 6 GeV

International Nuclear Information System (INIS)

Berthot, J.; Chen, J.P.; Chudakov, E.

2000-01-01

We propose a measurement of the Deep Virtual Compton Scattering process (DVCS) ep → epγ in Hall A at Jefferson Lab with a 6 GeV beam. We are able to explore the onset of Q 2 scaling, by measuring a beam helicity asymmetry for Q 2 ranging from 1.5 to 2.5 GeV 2 at x B ∼0.35. At this kinematics, the asymmetry is dominated by the DVCS - Bethe-Heitler (BH) interference, which is proportional to the imaginary part of the DVCS amplitude amplified by the full magnitude of the BH amplitude. The imaginary part of the DVCS amplitude is expected to scale early. Indeed, the imaginary part of the forward Compton amplitude measured in deep inelastic scattering (via the optical theorem) scales at Q 2 as low as 1 GeV 2 . If the scaling regime is reached, we will make an 8% measurement of the skewed parton distributions (SPD) contributing to the DVCS amplitude. Also, this experiment allows us to separately estimate the size of the higher-twist effects, since they are only suppressed by an additional factor 1/Q compared to the leading-twist term, and have a different angular dependence. We use a polarized electron beam and detect the scattered electron in the HRSe, the real photon in an electromagnetic calorimeter (under construction) and the recoil proton in a shielded scintillator array (to be constructed). This allows as to determine the difference in cross-sections for electrons of opposite helicities. This observable is directly linked to the SPD's. We estimate that 25 days of beam (600 hours) are needed to achieve this goal. (authors)

High-pressure system for Compton scattering experiments

International Nuclear Information System (INIS)

Oomi, G.; Honda, F.; Kagayama, T.; Itoh, F.; Sakurai, H.; Kawata, H.; Shimomura, O.

1998-01-01

High-pressure apparatus for Compton scattering experiments has been developed to study the momentum distribution of conduction electrons in metals and alloys at high pressure. This apparatus was applied to observe the Compton profile of metallic Li under pressure. It was found that the Compton profile at high pressure could be obtained within several hours by using this apparatus and synchrotron radiation. The result on the pressure dependence of the Fermi momentum of Li obtained here is in good agreement with that predicted from the free-electron model

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)

Extraction of Generalized Parton Distributions from combined Deeply Virtual Compton Scattering and Timelike Compton scattering fits

Science.gov (United States)

Boer, Marie

2017-09-01

Generalized Parton Distributions (GPDs) contain the correlation between the parton's longitudinal momentum and their transverse distribution. They are accessed through hard exclusive processes, such as Deeply Virtual Compton Scattering (DVCS). DVCS has already been measured in several experiments and several models allow for extracting GPDs from these measurements. Timelike Compton Scattering (TCS) is, at leading order, the time-reversal equivalent process to DVCS and accesses GPDs at the same kinematics. Comparing GPDs extracted from DVCS and TCS is a unique way for proving GPD universality. Combining fits from the two processes will also allow for better constraining the GPDs. We will present our method for extracting GPDs from DVCS and TCS pseudo-data. We will compare fit results from the two processes in similar conditions and present what can be expected in term of contraints on GPDs from combined fits.

Neutron Compton scattering from selectively deuterated acetanilide

Science.gov (United States)

Wanderlingh, U. N.; Fielding, A. L.; Middendorf, H. D.

With the aim of developing the application of neutron Compton scattering (NCS) to molecular systems of biophysical interest, we are using the Compton spectrometer EVS at ISIS to characterize the momentum distribution of protons in peptide groups. In this contribution we present NCS measurements of the recoil peak (Compton profile) due to the amide proton in otherwise fully deuterated acetanilide (ACN), a widely studied model system for H-bonding and energy transfer in biomolecules. We obtain values for the average width of the potential well of the amide proton and its mean kinetic energy. Deviations from the Gaussian form of the Compton profile, analyzed on the basis of an expansion due to Sears, provide data relating to the Laplacian of the proton potential.

Deeply virtual compton scattering at 6 GeV

Energy Technology Data Exchange (ETDEWEB)

Berthot, J. [Universite Blaise Pascal, Clermont-Ferrand II, Lab. de Physique Corpusculaire (CNRS), 63 - Aubiere (France); Chen, J.P.; Chudakov, E. [National Accelerator Facility, Newport News, Virginia (United States)] [and others

2000-07-01

We propose a measurement of the Deep Virtual Compton Scattering process (DVCS) ep {yields} ep{gamma} in Hall A at Jefferson Lab with a 6 GeV beam. We are able to explore the onset of Q{sup 2} scaling, by measuring a beam helicity asymmetry for Q{sup 2} ranging from 1.5 to 2.5 GeV{sup 2} at x{sub B}{approx}0.35. At this kinematics, the asymmetry is dominated by the DVCS - Bethe-Heitler (BH) interference, which is proportional to the imaginary part of the DVCS amplitude amplified by the full magnitude of the BH amplitude. The imaginary part of the DVCS amplitude is expected to scale early. Indeed, the imaginary part of the forward Compton amplitude measured in deep inelastic scattering (via the optical theorem) scales at Q{sup 2} as low as 1 GeV{sup 2}. If the scaling regime is reached, we will make an 8% measurement of the skewed parton distributions (SPD) contributing to the DVCS amplitude. Also, this experiment allows us to separately estimate the size of the higher-twist effects, since they are only suppressed by an additional factor 1/Q compared to the leading-twist term, and have a different angular dependence. We use a polarized electron beam and detect the scattered electron in the HRSe, the real photon in an electromagnetic calorimeter (under construction) and the recoil proton in a shielded scintillator array (to be constructed). This allows as to determine the difference in cross-sections for electrons of opposite helicities. This observable is directly linked to the SPD's. We estimate that 25 days of beam (600 hours) are needed to achieve this goal. (authors)

Development of TOF-PET using Compton scattering by plastic scintillators

International Nuclear Information System (INIS)

Kuramoto, M.; Nakamori, T.; Kimura, S.; Gunji, S.; Takakura, M.; Kataoka, J.

2017-01-01

We propose a time-of-flight (TOF) technique using plastic scintillators which have fast decay time of a few ns for positron emission tomography (PET). While the photoelectric absorption probability of the plastic for 511 keV gamma rays are extremely low due to its small density and effective atomic number, the cross section of Compton scattering is comparable to that of absorption by conventional inorganic scintillators. We thus propose TOF-PET using Compton scattering with plastic scintillators (Compton-PET), and performed fundamental experiments towards exploration of the Compton-PET capability. We demonstrated that the plastic scintillators achieved the better time resolution in comparison to LYSO(Ce) and GAGG(Ce) scintillators. In addition we evaluated the depth-of-interaction resolving capability with the plastic scintillators.

Development of TOF-PET using Compton scattering by plastic scintillators

Energy Technology Data Exchange (ETDEWEB)

Kuramoto, M., E-mail: kuramoto@maxwell.kj.yamagata-u.ac.jp [Yamagata University, Kojirakawa 1-4-12, Yamagata 990-8560 (Japan); Nakamori, T., E-mail: nakamori@maxwell.kj.yamagata-u.ac.jp [Yamagata University, Kojirakawa 1-4-12, Yamagata 990-8560 (Japan); Kimura, S.; Gunji, S.; Takakura, M. [Yamagata University, Kojirakawa 1-4-12, Yamagata 990-8560 (Japan); Kataoka, J. [Waseda University, Okubo 3-4-1, Shinjuku, Tokyo 169-8555 (Japan)

2017-02-11

We propose a time-of-flight (TOF) technique using plastic scintillators which have fast decay time of a few ns for positron emission tomography (PET). While the photoelectric absorption probability of the plastic for 511 keV gamma rays are extremely low due to its small density and effective atomic number, the cross section of Compton scattering is comparable to that of absorption by conventional inorganic scintillators. We thus propose TOF-PET using Compton scattering with plastic scintillators (Compton-PET), and performed fundamental experiments towards exploration of the Compton-PET capability. We demonstrated that the plastic scintillators achieved the better time resolution in comparison to LYSO(Ce) and GAGG(Ce) scintillators. In addition we evaluated the depth-of-interaction resolving capability with the plastic scintillators.

Development of TOF-PET using Compton scattering by plastic scintillators

Science.gov (United States)

Kuramoto, M.; Nakamori, T.; Kimura, S.; Gunji, S.; Takakura, M.; Kataoka, J.

2017-02-01

We propose a time-of-flight (TOF) technique using plastic scintillators which have fast decay time of a few ns for positron emission tomography (PET). While the photoelectric absorption probability of the plastic for 511 keV gamma rays are extremely low due to its small density and effective atomic number, the cross section of Compton scattering is comparable to that of absorption by conventional inorganic scintillators. We thus propose TOF-PET using Compton scattering with plastic scintillators (Compton-PET), and performed fundamental experiments towards exploration of the Compton-PET capability. We demonstrated that the plastic scintillators achieved the better time resolution in comparison to LYSO(Ce) and GAGG(Ce) scintillators. In addition we evaluated the depth-of-interaction resolving capability with the plastic scintillators.

Studies of coherent/Compton scattering method for bone mineral content measurement

International Nuclear Information System (INIS)

Sakurai, Kiyoko; Iwanami, Shigeru; Nakazawa, Keiji; Matsubayashi, Takashi; Imamura, Keiko.

1980-01-01

A measurement of bone mineral content by a coherent/Compton scattering method was described. A bone sample was irradiated by a collimated narrow beam of 59.6 keV gamma-rays emitted from a 300 mCi 241 Am source, and the scattered radiations were detected using a collimated pure germanium detector placed at 90 0 to the incident beam. The ratio of coherent to Compton peaks in a spectrum of the scattered radiations depends on the bone mineral content of the bone sample. The advantage of this method is that bone mineral content of a small region in a bone can be accurately measured. Assuming that bone consists of two components, protein and bone mineral, and that the mass absorption coefficient for Compton scattering is independent of material, the coherent to Compton scattering ratio is linearly related to the percentage in weight of bone mineral. A calibration curve was obtained by measuring standard samples which were mixed with Ca 3 (PO 4 ) 2 and H 2 O. The error due to the assumption about the mass absorption coefficient for Compton scattering and to the difference between true bone and standard samples was estimated to be less than 3% within the range from 10 to 60% in weight of bone mineral. The fat in bone affects an estimated value by only 1.5% when it is 20% in weight. For the clinical application of this method, the location to be analyzed should be selected before the measurement with two X-ray images viewed from the source and the detector. These views would be also used to correct the difference in absorption between coherent and Compton scattered radiations whose energies are slightly different from each other. The absorbed dose to the analyzed region was approximately 150 mrad. The time required for one measurement in this study was about 10 minutes. (author)

Analysis of materials in ducts by Compton scattering

International Nuclear Information System (INIS)

Gouveia, M.A.G.; Lopes, R.T.; Jesus, E.F.O. de; Camerini, C.S.

2000-01-01

This work presents the use of the Compton Scattering Technique as essay, for materials characterization in petroleum ducts. The essay have been accomplished in laboratory ambit, so that the presented results should be analyzed so that the system can come to be used in the field. The inspection was performed using Compton Scattering techniques, with two detectors aligned, in an angle of 90 degrees with a source of Cs-137 with energy of 662 keV. The results demonstrated the good capacity of the system to detect materials deposited in petroleum ducts during petroleum transportation. (author)

Representation of the virtual Compton amplitude for polarized scattering in the generalized Bjorken region

OpenAIRE

Blümlein, J.; Gezer, B.; Robaschik, D.

1999-01-01

The Compton amplitude is calculated in terms of expectation values of light-ray quark operators. As a technical tool we apply the nonlocal light-cone expansion. Thereby we express the expectation value of the vector light-ray operator with the help of the expectation value of the corresponding scalar operator of twist 2. This allows important simplifications. In the limit of forward scattering the integral relations between the twist-2 contributions of the structure functions are implied dire...

Constraint on Parameters of Inverse Compton Scattering Model for ...

Indian Academy of Sciences (India)

B2319+60, two parameters of inverse Compton scattering model, the initial Lorentz factor and the factor of energy loss of relativistic particles are constrained. Key words. Pulsar—inverse Compton scattering—emission mechanism. 1. Introduction. Among various kinds of models for pulsar radio emission, the inverse ...

Computer control in a compton scattering spectrometer

International Nuclear Information System (INIS)

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

1995-01-01

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

Deeply virtual Compton scattering. Results and future

International Nuclear Information System (INIS)

Nowak, W.D.

2005-03-01

Access to generalised parton distributions (GPDs) through deeply virtual Compton scattering (DVCS) is briefly described. Presently available experimental results on DVCS are summarized in conjunction with plans for future measurements. (orig.)

The experimental challenge of virtual compton scattering above 8 GeV

International Nuclear Information System (INIS)

Pierre Bertin; Yves Roblin; Charles Hyde-Wright

1999-01-01

We discuss the experimental issues confronting measurements of the Virtual Compton Scattering (VCS) reaction ep->ep gamma with electron beam energies 6-30 GeV. We specifically address the kinematics of Deeply Virtual Compton Scattering (Deep Inelastic Scattering, with coincident detection of the exclusive real photon nearly parallel to the virtual photon direction) and large transverse momentum VCS (High energy VCS of arbitrary Q 2 , and the recoil proton emitted with high momentum transverse to the virtual photon direction). We discuss the experimental equipment necessary for these measurements. For the DVCS, we emphasize the importance of the Bethe-Heitler-Compton interference terms that can be measured with the electron-positron (beam charge) asymmetry, and the electron beam helicity asymmetry

Use of implicit Monte Carlo radiation transport with hydrodynamics and compton scattering

International Nuclear Information System (INIS)

Fleck, J.A. Jr.

1971-03-01

It is shown that the combination of implicit radiation transport and hydrodynamics, Compton scattering, and any other energy transport can be simply carried out by a ''splitting'' procedure. Contributions to material energy exchange can be reckoned separately for hydrodynamics, radiation transport without scattering, Compton scattering, plus any other possible energy exchange mechanism. The radiation transport phase of the calculation would be implicit, but the hydrodynamics and Compton portions would not, leading to possible time step controls. The time step restrictions which occur on radiation transfer due to large Planck mean absorption cross-sections would not occur

Experimental confirmation of neoclassical Compton scattering theory

Energy Technology Data Exchange (ETDEWEB)

Aristov, V. V., E-mail: aristov@iptm.ru [Russian Academy of Sciences, Institute of Microelectronics Technology and High Purity Materials (Russian Federation); Yakunin, S. N. [National Research Centre “Kurchatov Institute” (Russian Federation); Despotuli, A. A. [Russian Academy of Sciences, Institute of Microelectronics Technology and High Purity Materials (Russian Federation)

2013-12-15

Incoherent X-ray scattering spectra of diamond and silicon crystals recorded on the BESSY-2 electron storage ring have been analyzed. All spectral features are described well in terms of the neoclassical scattering theory without consideration for the hypotheses accepted in quantum electrodynamics. It is noted that the accepted tabular data on the intensity ratio between the Compton and Rayleigh spectral components may significantly differ from the experimental values. It is concluded that the development of the general theory (considering coherent scattering, incoherent scattering, and Bragg diffraction) must be continued.

Laser Compton Scattering Gamma Ray Induced Photo-Trasmutation

CERN Document Server

Li, Dazhi

2004-01-01

High brightness beams of gamma rays produced with laser Compton scattering have the potential to realize photo-transmutation through (γ,n) reaction, implying an efficient method to dispose long-lived fission products. Preliminary investigations have been carried out in understanding the feasibility of development of a transmutation facility to repose nuclear waste. A laser Compton scattering experimental setup based on a storage ring started to generate gamma-ray beams for studying the coupling of gamma photons and nuclear giant resonance. This paper demonstrates the dependency of nuclear transmutation efficiency on target dimensions and gamma ray features. 197Au sample was adopted in our experiment, and experimental results correspond to the theoretical estimations.

A compact X-ray source based on Compton scattering

Energy Technology Data Exchange (ETDEWEB)

Bulyak, E.; Gladkikh, P.; Grigor' ev, Yu.; Guk, I.; Karnaukhov, I.; Khodyachikh, A.; Kononenko, S.; Mocheshnikov, N.; Mytsykov, A.; Shcherbakov, A. E-mail: shcherbakov@kipt.kharkov.ua; Tarasenko, A.; Telegin, Yu.; Zelinsky, A

2001-07-21

The main parameters of Kharkov electron storage ring N-100 with a beam energy range from 70 to 150 MeV are presented. The main results that were obtained in experimental researches are briefly described. The future of the N-100 upgrade to the development of the X-ray generator based on Compton back-scattering are presented. The electron beam energy range will be extended up to 250 MeV and the circumference of the storage ring will be 13.72 m. The lattice, parameters of the electron beam and the Compton back-scattering photons flux are described.

A compact X-ray source based on Compton scattering

International Nuclear Information System (INIS)

Bulyak, E.; Gladkikh, P.; Grigor'ev, Yu.; Guk, I.; Karnaukhov, I.; Khodyachikh, A.; Kononenko, S.; Mocheshnikov, N.; Mytsykov, A.; Shcherbakov, A.; Tarasenko, A.; Telegin, Yu.; Zelinsky, A.

2001-01-01

The main parameters of Kharkov electron storage ring N-100 with a beam energy range from 70 to 150 MeV are presented. The main results that were obtained in experimental researches are briefly described. The future of the N-100 upgrade to the development of the X-ray generator based on Compton back-scattering are presented. The electron beam energy range will be extended up to 250 MeV and the circumference of the storage ring will be 13.72 m. The lattice, parameters of the electron beam and the Compton back-scattering photons flux are described

Compton scattering and γ-quanta monochromatization

International Nuclear Information System (INIS)

Goryachev, B.I.; Shevchenko, V.G.

1979-01-01

The γ-quanta monochromatization method is proposed for sdudying high-excited states and mechanisms of nuclei photodisintegration. The method is based on the properties of photon Compton scattering. It permits to obtain high energy resolution without accurate analysis of the particle energies taking part in the scattering process. A possible design of the compton γ- monochromator is presented. The γ-quanta scatterer of the elements with a small nucleus charge (e.g. LiH) is placed inside the β-spectrometer of low resolution. The monochromator is expected to operate in the γ-beam of the high-current synchrotron, and it provides for a rather good energy resolution rho(W) while studying the high-excited nucleus states (rho(W) approximately 2% in the range of the giant dipole resonance). With the γ-quanta energy growth rho(W) increases as Wsup(0.6). The monochromator permits to obtain high statistical accuracy for a smaller period of time (at a considerably better energy resolution) than while working with a bremsstrahlung spectrum. The yield of quasimonochromatic photons related to the ΔW(ΔW = rho(W)W) range of energy resolution increases as Wsup(0.6). This fact makes it promjssing to use monochromator in the energy range considerably exceeding the characteristic energy of the gigantic dipole resonance

Pulsar high energy emission due to inverse Compton scattering

Energy Technology Data Exchange (ETDEWEB)

Lyutikov, Maxim

2013-06-15

We discuss growing evidence that pulsar high energy is emission is generated via Inverse Compton mechanism. We reproduce the broadband spectrum of Crab pulsar, from UV to very high energy gamma-rays - nearly ten decades in energy, within the framework of the cyclotron-self-Compton model. Emission is produced by two counter-streaming beams within the outer gaps, at distances above ∼ 20 NS radii. The outward moving beam produces UV-X-ray photons via Doppler-booster cyclotron emission, and GeV photons by Compton scattering the cyclotron photons produced by the inward going beam. The scattering occurs in the deep Klein-Nishina regime, whereby the IC component provides a direct measurement of particle distribution within the magnetosphere. The required plasma multiplicity is high, ∼10{sup 6} – 10{sup 7}, but is consistent with the average particle flux injected into the pulsar wind nebula.

Compton profiles by inelastic ion-electron scattering

International Nuclear Information System (INIS)

Boeckl, H.; Bell, F.

1983-01-01

It is shown that Compton profiles (CP) can be measured by inelastic ion-electron scattering. Within the impulse approximation the binary-encounter peak (BEP) reflects the CP of the target atom whereas the electron-loss peak (ELP) is given by projectile CP's. Evaluation of experimental data reveals that inelastic ion-electron scattering might be a promising method to supply inelastic electron or photon scattering for the determination of target CP's. The measurement of projectile CP's is unique to ion scattering since one gains knowledge about wave-function effects because of the high excitation degree of fast heavy-ion projectiles

Differential cross sections of proton Compton scattering at photon laboratory energies between 700 and 1000 MeV

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.)

Relativistic wave equations and compton scattering

International Nuclear Information System (INIS)

Sutanto, S.H.; Robson, B.A.

1998-01-01

Full text: Recently an eight-component relativistic wave equation for spin-1/2 particles was proposed.This equation was obtained from a four-component spin-1/2 wave equation (the KG1/2 equation), which contains second-order derivatives in both space and time, by a procedure involving a linearisation of the time derivative analogous to that introduced by Feshbach and Villars for the Klein-Gordon equation. This new eight-component equation gives the same bound-state energy eigenvalue spectra for hydrogenic atoms as the Dirac equation but has been shown to predict different radiative transition probabilities for the fine structure of both the Balmer and Lyman a-lines. Since it has been shown that the new theory does not always give the same results as the Dirac theory, it is important to consider the validity of the new equation in the case of other physical problems. One of the early crucial tests of the Dirac theory was its application to the scattering of a photon by a free electron: the so-called Compton scattering problem. In this paper we apply the new theory to the calculation of Compton scattering to order e 2 . It will be shown that in spite of the considerable difference in the structure of the new theory and that of Dirac the cross section is given by the Klein-Nishina formula

Importance of Doppler broadening in Compton scatter imaging techniques

Science.gov (United States)

Rao, Donepudi V.; Takeda, Tohoru; Itai, Yuji; Seltzer, S. M.; Hubbell, John H.; Zeniya, Tsutomu; Akatsuka, Takao; Cesareo, Roberto; Brunetti, Antonio; Gigante, Giovanni E.

2001-12-01

Compton scattering is a potential tool for the determination of bone mineral content or tissue density for dose planning purposes, and requires knowledge of the energy distribution of the X-rays through biological materials of medical interest in the X-ray and (gamma) -ray region. The energy distribution is utilized in a number of ways in diagnostic radiology, for example, in determining primary photon spectra, electron densities in separate volumes, and in tomography and imaging. The choice of the X-ray energy is more related to X-ray absorption, where as that of the scattering angle is more related to geometry. The evaluation of all the contributions are mandatory in Compton profile measurements and is important in X-ray imaging systems in order to achieve good results. In view of this, Compton profile cross-sections for few biological materials are estimated at nineteen K(alpha) X-ray energies and 60 keV (Am-241) photons. Energy broadening, geometrical broadening from 1 to 180 degree(s), FWHM of J(Pz) and FWHM of Compton energy broadening has been evaluated at various incident photon energies. These values are estimated around the centroid of the Compton profile with an energy interval of 0.1 keV and 1.0 keV for 60 keV photons. The interaction cross sections for the above materials are estimated using fractions-by-weight of the constituent elements. Input data for these tables are purely theoretical.

A method for determination mass absorption coefficient of gamma rays by Compton scattering

International Nuclear Information System (INIS)

El Abd, A.

2014-01-01

A method was proposed for determination mass absorption coefficient of gamma rays for compounds, alloys and mixtures. It is based on simulating interaction processes of gamma rays with target elements having atomic numbers from Z=1 to Z=92 using the MCSHAPE software. Intensities of Compton scattered gamma rays at saturation thicknesses and at a scattering angle of 90° were calculated for incident gamma rays of different energies. The obtained results showed that the intensity of Compton scattered gamma rays at saturations and mass absorption coefficients can be described by mathematical formulas. These were used to determine mass absorption coefficients for compound, alloys and mixtures with the knowledge of their Compton scattered intensities. The method was tested by calculating mass absorption coefficients for some compounds, alloys and mixtures. There is a good agreement between obtained results and calculated ones using WinXom software. The advantages and limitations of the method were discussed. - Highlights: • Compton scattering of γ−rays was used for determining mass absorption coefficient. • Scattered intensities were determined by the MCSHAPE software. • Mass absorption coefficients were determined for some compounds, mixtures and alloys. • Mass absorption coefficients were calculated by Winxcom software. • Good agreements were found between determined and calculated results

Model independent dispersion approach to proton Compton scattering

International Nuclear Information System (INIS)

Caprini, I.; Radescu, E.E.

1980-12-01

The proton Compton scattering at low and intermediate energies is studied by means of a dispersion framework which exploits in an optimal way the (fixed momentum transfer) analyticity properties of the amplitudes in conjunction with the consequences of the (s-channel) unitarity. The mathematical background of the work consists of methods specific to boundary value problems for analytic vector-valued functions and interpolation theory. In comparison with previous related work, the external problems to be solved now are much more difficult because of the inclusion of the photoproduction input and also lead to additional computational complications. The lower bounds on the differential cross-section, obtained without any reference to subtractions and annihilation channel contributions, appear sufficiently restrictive to evidentiate rigorously some inconsistencies between results of single pion photoproduction multipole extractions and proton Compton scattering data. (author)

X-ray generator based on Compton scattering

NARCIS (Netherlands)

Androsov, V.P.; Agafonov, A.V.; Botman, J.I.M.; Bulyak, E.V.; Drebot, I.; Gladkikh, P.I.; Grevtsev, V.; Ivashchenko, V.; Karnaukhov, I.M.; Lapshin, V.I.

2005-01-01

Nowadays, the sources of the X-rays based on a storage ring with low beam energy and Compton scattering of intense laser beam are under development in several laboratories. In the paper the state-of-art in development and construction of cooperative project of a Kharkov advanced X-ray source NESTOR

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)

Description of the double Compton spectrometer at Mayence MPI

International Nuclear Information System (INIS)

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

1977-01-01

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

Precise tests of x-ray scattering theories in the Compton regime

International Nuclear Information System (INIS)

Dunford, R. W.; Gemmell, D. S.; Kanter, E. P.; Kraessig, B.; Southworth, S. H.; Young, L.

1999-01-01

The authors report two experiments intended to test the accuracy of state-of-the-art theoretical predictions for x-ray scattering from low-Z atoms. The first one deals with the differential x-ray scattering cross sections in Ne and He from 11-22 keV and the Ne Compton-to-Rayleigh scattering ratio in this energy range. It was found that, in order to be consistent with the experimental results, an accurate description at low Z must include nonlocal exchange, electron correlation, and dynamic effects. The second experiment concerns the ratio of helium double-to-single ionization for Compton scattering in the 8-28 keV energy range where published experimental and theoretical results so far fail to give a consistent picture. The progress of the experiment and the data analysis is reported

Colour dipoles and virtual Compton scattering

International Nuclear Information System (INIS)

McDermott, M.

2002-01-01

An analysis of Deeply Virtual Compton Scattering (DVCS) is made within the colour dipole model. We compare and contrast two models for the dipole cross-section which have been successful in describing structure function data. Both models agree with the available cross section data on DVCS from HERA. We give predictions for various azimuthal angle asymmetries in HERA kinematics and for the DVCS cross section in the THERA region. (orig.)

Virtual Compton Scattering off a Spinless Target in the AdS/QCD correspondence

Energy Technology Data Exchange (ETDEWEB)

Wallon, Samuel [Laboratoire de Physique Theorique d' Orsay - LPT, Bat. 210, Univ. Paris-Sud 11, 91405 Orsay Cedex (France); Marquet, Cyrille [IPhT - Institut de Physique Theorique, Orme des Merisiers bat. 774, PC 136, CEA/DSM/IPhT, CEA/Saclay, F-91191 Gif-sur-Yvette Cedex (France); Roiesnel, Claude [Centre de Physique Theorique - CPHT, UMR 7644, Ecole Polytechnique, Bat. 6, RDC, F91128 Palaiseau Cedex (France)

2010-07-01

We study the doubly virtual Compton scattering off a spinless target {gamma}* P {yields} {gamma}* P' within the Anti-de Sitter(AdS)/QCD formalism. We find that the general structure allowed by the Lorentz invariance and gauge invariance of the Compton amplitude is not easily reproduced with the standard recipes of the AdS/QCD correspondence. In the soft-photon regime, where the semi-classical approximation is supposed to apply best, we show that the measurements of the electric and magnetic polarizabilities of a target like the charged pion in real Compton scattering, can already serve as stringent tests. (author)

Compton Scattering of Quasi-Real Virtual Photons at LEP

CERN Document Server

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.

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.)

Design Study for Direction Variable Compton Scattering Gamma Ray

Science.gov (United States)

Kii, T.; Omer, M.; Negm, H.; Choi, Y. W.; Kinjo, R.; Yoshida, K.; Konstantin, T.; Kimura, N.; Ishida, K.; Imon, H.; Shibata, M.; Shimahashi, K.; Komai, T.; Okumura, K.; Zen, H.; Masuda, K.; Hori, T.; Ohgaki, H.

2013-03-01

A monochromatic gamma ray beam is attractive for isotope-specific material/medical imaging or non-destructive inspection. A laser Compton scattering (LCS) gamma ray source which is based on the backward Compton scattering of laser light on high-energy electrons can generate energy variable quasi-monochromatic gamma ray. Due to the principle of the LCS gamma ray, the direction of the gamma beam is limited to the direction of the high-energy electrons. Then the target object is placed on the beam axis, and is usually moved if spatial scanning is required. In this work, we proposed an electron beam transport system consisting of four bending magnets which can stick the collision point and control the electron beam direction, and a laser system consisting of a spheroidal mirror and a parabolic mirror which can also stick the collision point. Then the collision point can be placed on one focus of the spheroid. Thus gamma ray direction and collision angle between the electron beam and the laser beam can be easily controlled. As the results, travelling direction of the LCS gamma ray can be controlled under the limitation of the beam transport system, energy of the gamma ray can be controlled by controlling incident angle of the colliding beams, and energy spread can be controlled by changing the divergence of the laser beam.

Constraints on low energy Compton scattering amplitudes

International Nuclear Information System (INIS)

Raszillier, I.

1979-04-01

We derive the constraints and correlations of fairly general type for Compton scattering amplitudes at energies below photoproduction threshold and fixed momentum transfer, following from (an upper bound on) the corresponding differential cross section above photoproduction threshold. The derivation involves the solution of an extremal problem in a certain space of vector - valued analytic functions. (author)

A Compton scattering technique to determine wood density and locating defects in it

International Nuclear Information System (INIS)

Tondon, Akash; Sandhu, B. S.; Singh, Bhajan; Singh, Mohinder

2015-01-01

A Compton scattering technique is presented to determine density and void location in the given wooden samples. The technique uses a well collimated gamma ray beam from 137 Cs along with the NaI(Tl) scintillation detector. First, a linear relationship is established between Compton scattered intensity and known density of chemical compounds, and then density of the wood is determined from this linear relation. In another experiment, the ability of penetration of gamma rays is explored to detect voids in wooden (low Z) sample. The sudden reduction in the Compton scattered intensities agrees well with the position and size of voids in the wooden sample. It is concluded that wood density and the voids of size ∼ 4 mm and more can be detected easily by this method

Deeply virtual Compton scattering off "4He

International Nuclear Information System (INIS)

Hattawy, M.

2015-01-01

The "4He nucleus is of particular interest to study nuclear GPDs (Generalized Parton Distributions) as its partonic structure is described by only one chirally-even GPD. It is also a simple few-body system and has a high density that makes it the ideal target to investigate nuclear effects on partons. The experiment described in this thesis is JLab-E08-24, which was carried out in 2009 by the CLAS collaboration during the 'EG6' run. In this experiment, a 6 GeV longitudinally-polarized electron beam was scattered onto a 6 atm "4He gaseous target. During this experiment, in addition to the CLAS detector, a Radial Time Projection Chamber (RTPC), to detect low-energy nuclear recoils, and an Inner Calorimeter (IC), to improve the detection of photons at very forward angles, were used. We carried out a full analysis on our 6 GeV dataset, showing the feasibility of measuring exclusive nuclear Deeply Virtual Compton Scattering (DVCS) reactions. The analysis included: the identification of the final-state particles, the DVCS event selection, the π"0 background subtraction. The beam-spin asymmetry was then extracted for both DVCS channels and compared to the ones of the free-proton DVCS reaction, and to theoretical predictions from two models. Finally, the real and the imaginary parts of the "4He CFF (Compton Form Factor) HA have been extracted. Different levels of agreement were found between our measurements and the theoretical calculations. This thesis is organized as follows: In chapter 1, the available theoretical tools to study hadronic structure are presented, with an emphasis on the nuclear effects and GPDs. In chapter 2, the characteristics of the CLAS spectrometer are reviewed. In chapter 3, the working principle and the calibration aspects of the RTPC are discussed. In chapter 4, the identification of the final-state particles and the Monte-Carlo simulation are presented. In chapter 5, the selection of the DVCS events, the background subtraction, and uncertainty

Electronic properties of Be and Al by Compton scattering technique

International Nuclear Information System (INIS)

Aguiar, J.C.; Di Rocco, H.O.

2011-01-01

In this work, electronic properties of beryllium and aluminum are examined by using Compton scattering technique. The method is based on the irradiation of samples using a beam narrow of mono- energetic photons of 59.54 keV product of radioactive decay of Am -241 . Scattered radiation is collected by a high resolution semiconductor detector positioned at an angle of 90°. The measured spectrum is commonly called Compton profile and contains useful information about the electronic structure of the material. The experimental results are compared with theoretical calculations such as density functional theory showing a good agreement. However, these results show some discrepancies with many libraries used in codes such as Monte Carlo simulation. Since these libraries are based on the values tabulated by Biggs, Mendelsohn and Mann 1975 thus overestimating the scattered radiation on the material. (authors) [es

Compton scattering and electron-atom scattering in an elliptically polarized laser field of relativistic radiation power

International Nuclear Information System (INIS)

Panek, P.; Kaminski, J.Z.; Ehlotzky, F.

2003-01-01

Presently available laser sources can yield powers for which the ponderomotive energy of an electron U p can be equal to or even larger than the rest energy mc 2 of an electron. Therefore it has become of interest to consider fundamental radiation-induced or assisted processes in such powerful laser fields. In the present work we consider laser-induced Compton scattering and laser-assisted electron atom scattering in such fields, assuming that the laser beam has arbitrary elliptic polarization. We investigate in detail the angular and polarisation dependence of the differential cross-sections of the two laser-induced or laser-assisted nonlinear processes as a function of the order N of absorbed or emitted laser photons ω. The present work is a generalization of our previous analysis of Compton scattering and electron-atom scattering in a linearly polarized laser field. (authors)

High-Energy Compton Scattering Light Sources

CERN Document Server

Hartemann, Fred V; Barty, C; Crane, John; Gibson, David J; Hartouni, E P; Tremaine, Aaron M

2005-01-01

No monochromatic, high-brightness, tunable light sources currently exist above 100 keV. Important applications that would benefit from such new hard x-ray sources include: nuclear resonance fluorescence spectroscopy, time-resolved positron annihilation spectroscopy, and MeV flash radiography. The peak brightness of Compton scattering light sources is derived for head-on collisions and found to scale with the electron beam brightness and the drive laser pulse energy. This gamma 2

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

International Nuclear Information System (INIS)

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

2002-01-01

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

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

CERN Document Server

Gladkikh, P I; Karnaukhov, I M

2002-01-01

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

A method for determination mass absorption coefficient of gamma rays by Compton scattering.

Science.gov (United States)

El Abd, A

2014-12-01

A method was proposed for determination mass absorption coefficient of gamma rays for compounds, alloys and mixtures. It is based on simulating interaction processes of gamma rays with target elements having atomic numbers from Z=1 to Z=92 using the MCSHAPE software. Intensities of Compton scattered gamma rays at saturation thicknesses and at a scattering angle of 90° were calculated for incident gamma rays of different energies. The obtained results showed that the intensity of Compton scattered gamma rays at saturations and mass absorption coefficients can be described by mathematical formulas. These were used to determine mass absorption coefficients for compound, alloys and mixtures with the knowledge of their Compton scattered intensities. The method was tested by calculating mass absorption coefficients for some compounds, alloys and mixtures. There is a good agreement between obtained results and calculated ones using WinXom software. The advantages and limitations of the method were discussed. Copyright © 2014 Elsevier Ltd. All rights reserved.

Compton scattering at finite temperature: thermal field dynamics approach

International Nuclear Information System (INIS)

Juraev, F.I.

2006-01-01

Full text: Compton scattering is a classical problem of quantum electrodynamics and has been studied in its early beginnings. Perturbation theory and Feynman diagram technique enables comprehensive analysis of this problem on the basis of which famous Klein-Nishina formula is obtained [1, 2]. In this work this problem is extended to the case of finite temperature. Finite-temperature effects in Compton scattering is of practical importance for various processes in relativistic thermal plasmas in astrophysics. Recently Compton effect have been explored using closed-time path formalism with temperature corrections estimated [3]. It was found that the thermal cross section can be larger than that for zero-temperature by several orders of magnitude for the high temperature realistic in astrophysics [3]. In our work we use a main tool to account finite-temperature effects, a real-time finite-temperature quantum field theory, so-called thermofield dynamics [4, 5]. Thermofield dynamics is a canonical formalism to explore field-theoretical processes at finite temperature. It consists of two steps, doubling of Fock space and Bogolyubov transformations. Doubling leads to appearing additional degrees of freedom, called tilded operators which together with usual field operators create so-called thermal doublet. Bogolyubov transformations make field operators temperature-dependent. Using this formalism we treat Compton scattering at finite temperature via replacing in transition amplitude zero-temperature propagators by finite-temperature ones. As a result finite-temperature extension of the Klein-Nishina formula is obtained in which differential cross section is represented as a sum of zero-temperature cross section and finite-temperature correction. The obtained result could be useful in quantum electrodynamics of lasers and for relativistic thermal plasma processes in astrophysics where correct account of finite-temperature effects is important. (author)

Resonant Inverse Compton Scattering Spectra from Highly Magnetized Neutron Stars

Science.gov (United States)

Wadiasingh, Zorawar; Baring, Matthew G.; Gonthier, Peter L.; Harding, Alice K.

2018-02-01

Hard, nonthermal, persistent pulsed X-ray emission extending between 10 and ∼150 keV has been observed in nearly 10 magnetars. For inner-magnetospheric models of such emission, resonant inverse Compton scattering of soft thermal photons by ultrarelativistic charges is the most efficient production mechanism. We present angle-dependent upscattering spectra and pulsed intensity maps for uncooled, relativistic electrons injected in inner regions of magnetar magnetospheres, calculated using collisional integrals over field loops. Our computations employ a new formulation of the QED Compton scattering cross section in strong magnetic fields that is physically correct for treating important spin-dependent effects in the cyclotron resonance, thereby producing correct photon spectra. The spectral cutoff energies are sensitive to the choices of observer viewing geometry, electron Lorentz factor, and scattering kinematics. We find that electrons with energies ≲15 MeV will emit most of their radiation below 250 keV, consistent with inferred turnovers for magnetar hard X-ray tails. More energetic electrons still emit mostly below 1 MeV, except for viewing perspectives sampling field-line tangents. Pulse profiles may be singly or doubly peaked dependent on viewing geometry, emission locale, and observed energy band. Magnetic pair production and photon splitting will attenuate spectra to hard X-ray energies, suppressing signals in the Fermi-LAT band. The resonant Compton spectra are strongly polarized, suggesting that hard X-ray polarimetry instruments such as X-Calibur, or a future Compton telescope, can prove central to constraining model geometry and physics.

An energy-subtraction Compton scatter camera design for in vivo medical imaging of radiopharmaceuticals

International Nuclear Information System (INIS)

Rohe, R.C.; Valentine, J.D.

1996-01-01

A Compton scatter camera (CSC) design is proposed for imaging radioisotopes used as biotracers. A clinical version may increase sensitivity by a factor of over 100, while maintaining or improving spatial resolution, as compared with existing Anger cameras that use lead collimators. This novel approach is based on using energy subtraction (ΔE = E 0 - E SC , where E 0 , ΔE, and E SC are the energy of the emitted gamma ray, the energy deposited by the initial Compton scatter, and the energy of the Compton scattered photon) to determine the amount of energy deposited in the primary system. The energy subtraction approach allows the requirement of high energy resolution to be placed on a secondary detector system instead of the primary detector system. Requiring primary system high energy resolution has significantly limited previous CSC designs for medical imaging applications. Furthermore, this approach is dependent on optimizing the camera design for data acquisition of gamma rays that undergo only one Compton scatter in a low-Z primary detector system followed by a total absorption of the Compton scattered photon in a high-Z secondary detector system. The proposed approach allows for a more compact primary detector system, a more simplified pulse processing interface, and a much less complicated detector cooling scheme as compared with previous CSC designs. Analytical calculations and Monte Carlo simulation results for some specific detector materials and geometries are presented

Formal analogy between Compton scattering and Doppler effect

DEFF Research Database (Denmark)

Nielsen, A.; Olsen, Jørgen Seir

1966-01-01

Viewed from the scatterer, the energy of the incoming photon or particle is equal to that of the outgoing, and the angle of incidence is equal to the angle of reflection, when the direction of the velocity of the scatterer after the collision is taken as reference. This paper sets out to prove...... this statement in a more simple and direct way. The authors only consider the Compton scatting process as it is quite analogous to the particle case....

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

Deeply virtual Compton scattering at Jefferson Laboratory

Energy Technology Data Exchange (ETDEWEB)

Biselli, Angela S. [Fairfield University - Department of Physics 1073 North Benson Road, Fairfield, CT 06430, USA; Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

2016-08-01

The generalized parton distributions (GPDs) have emerged as a universal tool to describe hadrons in terms of their elementary constituents, the quarks and the gluons. Deeply virtual Compton scattering (DVCS) on a proton or neutron ($N$), $e N \\rightarrow e' N' \\gamma$, is the process more directly interpretable in terms of GPDs. The amplitudes of DVCS and Bethe-Heitler, the process where a photon is emitted by either the incident or scattered electron, can be accessed via cross-section measurements or exploiting their interference which gives rise to spin asymmetries. Spin asymmetries, cross sections and cross-section differences can be connected to different combinations of the four leading-twist GPDs (${H}$, ${E}$, ${\\tilde{H}}$, ${\\tilde{E}}$) for each quark flavors, depending on the observable and on the type of target. This paper gives an overview of recent experimental results obtained for DVCS at Jefferson Laboratory in the halls A and B. Several experiments have been done extracting DVCS observables over large kinematics regions. Multiple measurements with overlapping kinematic regions allow to perform a quasi-model independent extraction of the Compton form factors, which are GPDs integrals, revealing a 3D image of the nucleon.

Describing Compton scattering and two-quanta positron annihilation based on Compton profiles: Two models suited for the Monte Carlo method

CERN Document Server

Bohlen, TT; Patera, V; Sala, P R

2012-01-01

An accurate description of the basic physics processes of Compton scattering and positron annihilation in matter requires the consideration of atomic shell structure effects and, in specific, the momentum distributions of the atomic electrons. Two algorithms which model Compton scattering and two-quanta positron annihilation at rest accounting for shell structure effects are proposed. Two-quanta positron annihilation is a physics process which is of particular importance for applications such as positron emission tomography (PET). Both models use a detailed description of the processes which incorporate consistently Doppler broadening and binding effects. This together with the relatively low level of complexity of the models makes them particularly suited to be employed by fast sampling methods for Monte Carlo particle transport. Momentum distributions of shell electrons are obtained from parametrized one-electron Compton profiles. For conduction electrons, momentum distributions are derived in the framework...

Virtual Compton Scattering off a Spinless Target in the AdS/QCD correspondence

CERN Document Server

Marquet, C.; Wallon, S.

2010-01-01

We perform a study of the doubly virtual Compton scattering off a spinless target gamma* P -> gamma* P' within the Anti-de Sitter(AdS)/QCD formalism. We find that the general structure allowed by the Lorentz invariance and gauge invariance of the Compton amplitude is not easily reproduced with the standard recipes of the AdS/QCD correspondence. In the soft-photon regime, where the semi-classical approximation is supposed to apply best, we show that the measurements of the electric and magnetic polarizabilities of a target like the charged pion in real Compton scattering, can already serve as stringent tests, and presumably exclude results based on the AdS/QCD correspondence in its minimal version.

Connections between Compton scattering and pion photoproduction in the delta region

International Nuclear Information System (INIS)

Mukhopadhyay, N.C.; Benmerrouche, M.

1992-01-01

Using textbook tools like analyticity, unitarity and optical theorem, the authors discuss the relationship between pion-nucleon scattering, pion photoproduction and Compton scattering in the Δ(1232) resonance region. They review the relevant data and draw conclusions pertinent to the QCD-inspired models. 27 refs

Future measurements of deeply virtual Compton scattering

International Nuclear Information System (INIS)

Korotkov, V.A.; Nowak, W.D.

2001-09-01

Prospects for future measurements of Deeply Virtual Compton Scattering are studied using different simple models for parameterizations of generalized parton distributions (GPDs). Measurements of the lepton charge and lepton beam helicity asymmetry will yield important input for theoretical models towards the future extraction of GPDs. The kinematics of the HERMES experiment, complemented with a recoil detector, was adopted to arrive at realistic projected statistical uncertainties. (orig.)

High-energy electroweak neutrino-nucleon deeply virtual Compton scattering

International Nuclear Information System (INIS)

Machado, Magno V. T.

2007-01-01

In this work we estimate the differential and total cross sections for the high-energy deeply virtual Compton scattering in the weak sector. In the weak neutral sector one considers neutrino scattering off an unpolarized proton target through the exchange of Z 0 . We numerically compute the process Z*p→γp within the QCD color dipole formalism, which successfully describes the current high-energy electromagnetic DVCS experimental data. We also discuss possible applications for the weak charged sector and perform predictions for scattering on nuclear targets

Comprehensive study of observables in Compton scattering on the nucleon

Science.gov (United States)

Grießhammer, Harald W.; McGovern, Judith A.; Phillips, Daniel R.

2018-03-01

We present an analysis of 13 observables in Compton scattering on the proton. Cross sections, asymmetries with polarised beam and/or targets, and polarisation-transfer observables are investigated for energies up to the Δ(1232) resonance to determine their sensitivity to the proton's dipole scalar and spin polarisabilities. The Chiral Effective Field Theory Compton amplitude we use is complete at N4LO, O(e2δ4), for photon energies ω˜ m_{π}, and so has an accuracy of a few per cent there. At photon energies in the resonance region, it is complete at NLO, O(e2δ0), and so its accuracy there is about 20%. We find that for energies from pion-production threshold to about 250 MeV, multiple asymmetries have significant sensitivity to presently ill-determined combinations of proton spin polarisabilities. We also argue that the broad outcomes of this analysis will be replicated in complementary theoretical approaches, e.g., dispersion relations. Finally, we show that below the pion-production threshold, 6 observables suffice to reconstruct the Compton amplitude, and above it 11 are required. Although not necessary for polarisability extractions, this opens the possibility to perform "complete" Compton-scattering experiments. An interactive Mathematica notebook, including results for the neutron, is available from judith.mcgovern@manchester.ac.uk.

Sensitivity booster for DOI-PET scanner by utilizing Compton scattering events between detector blocks

Energy Technology Data Exchange (ETDEWEB)

Yoshida, Eiji, E-mail: rush@nirs.go.jp; Tashima, Hideaki; Yamaya, Taiga

2014-11-01

In a conventional PET scanner, coincidence events are measured with a limited energy window for detection of photoelectric events in order to reject Compton scatter events that occur in a patient, but Compton scatter events caused in detector crystals are also rejected. Scatter events within the patient causes scatter coincidences, but inter crystal scattering (ICS) events have useful information for determining an activity distribution. Some researchers have reported the feasibility of PET scanners based on a Compton camera for tracing ICS into the detector. However, these scanners require expensive semiconductor detectors for high-energy resolution. In the Anger-type block detector, single photons interacting with multiple detectors can be obtained for each interacting position and complete information can be gotten just as for photoelectric events in the single detector. ICS events in the single detector have been used to get coincidence, but single photons interacting with multiple detectors have not been used to get coincidence. In this work, we evaluated effect of sensitivity improvement using Compton kinetics in several types of DOI-PET scanners. The proposed method promises to improve the sensitivity using coincidence events of single photons interacting with multiple detectors, which are identified as the first interaction (FI). FI estimation accuracy can be improved to determine FI validity from the correlation between Compton scatter angles calculated on the coincidence line-of-response. We simulated an animal PET scanner consisting of 42 detectors. Each detector block consists of three types of scintillator crystals (LSO, GSO and GAGG). After the simulation, coincidence events are added as information for several depth-of-interaction (DOI) resolutions. From the simulation results, we concluded the proposed method promises to improve the sensitivity considerably when effective atomic number of a scintillator is low. Also, we showed that FI estimate

Differential cross sections of proton Compton scattering at photon laboratory energies between 1.2 and 1.7 GeV

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.)

The GPD H and spin correlations in wide-angle Compton scattering

Energy Technology Data Exchange (ETDEWEB)

Kroll, P. [Universitaet Wuppertal, Fachbereich Physik, Wuppertal (Germany)

2017-06-15

Wide-angle Compton scattering (WACS) is discussed within the handbag approach in which the amplitudes are given by products of hard subprocess amplitudes and form factors, specific to Compton scattering, which represent 1/x-moments of generalized parton distributions (GPDs). The quality of our present knowledge of these form factors and of the underlying GPDs is examined. As will be discussed in some detail the form factor R{sub A} and the underlying GPD H are poorly known. It is argued that future data on the spin correlations A{sub LL} and/or K{sub LL} will allow for an extraction of R{sub A} which can be used to constrain the large -t behavior of H. (orig.)

Compton scatter correction in case of multiple crosstalks in SPECT imaging.

Science.gov (United States)

Sychra, J J; Blend, M J; Jobe, T H

1996-02-01

A strategy for Compton scatter correction in brain SPECT images was proposed recently. It assumes that two radioisotopes are used and that a significant portion of photons of one radioisotope (for example, Tc99m) spills over into the low energy acquisition window of the other radioisotope (for example, Tl201). We are extending this approach to cases of several radioisotopes with mutual, multiple and significant photon spillover. In the example above, one may correct not only the Tl201 image but also the Tc99m image corrupted by the Compton scatter originating from the small component of high energy Tl201 photons. The proposed extension is applicable to other anatomical domains (cardiac imaging).

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

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

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.

Compton scattering on 208Pb

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.)

Virtual compton scattering at low energy

International Nuclear Information System (INIS)

Lhuillier, D.

1997-09-01

The work described in this PhD is a study of the Virtual Compton scattering (VCS) off the proton at low energy, below pion production threshold. Our experiment has been carried out at MAMI in the collaboration with the help of two high resolution spectrometers. Experimentally, the VCS process is the electroproduction of photons off a liquid hydrogen target. First results of data analysis including radiative corrections are presented and compared with low energy theorem prediction. VCS is an extension of the Real Compton Scattering. The virtuality of the incoming photon allows us to access new observables of the nucleon internal structure which are complementarity to the elastic form factors: the generalized polarizabilities (GP). They are function of the squared invariant mass of the virtual photo. The mass limit of these observables restore the usual electric and magnetic polarizabilities. Our experiment is the first measurement of the VCS process at a virtual photon mass equals 0.33 Ge V square. The experimental development presents the analysis method. The high precision needed in the absolute cross-section measurement required an accurate estimate of radiative corrections to the VCS. This new calculation, which has been performed in the dimensional regulation scheme, composes the theoretical part of this thesis. At low q', preliminary results agree with low energy theorem prediction. At higher q', substraction of low energy theorem contribution to extract GP is discussed. (author)

Study of the proton structure by measurements of polarization transfers in real Compton scattering at J Lab

International Nuclear Information System (INIS)

Fanelli, C.; Salme, G.; Cisbani, E.; Hamilton, D.; Wojtsekhowski, B.

2014-01-01

A preliminary analysis of polarization-transfer data at large scattering angle (70 degrees), obtained in an experiment of real Compton scattering on proton, performed in Hall-C of Jefferson Lab, is presented. It is also discussed the relevance of this kind of experiments for shedding light on the non-perturbative structure of the proton, at low energy, and on the transition from the non-perturbative regime to the perturbative one, that occurs at high energy. Moreover, the possibility to extract Compton form factors and the Generalized Parton Distributions (GPD), one of the most promising theoretical tool to determine the total angular momentum contribution of quarks and gluons to nucleon spin, is emphasized. The preliminary results appear consistent with GPD's based and Regge predictions. This is not sufficient yet to exclude pQCD COZ (Chernyak-Oglobin-Zhitnistsky) model, but it is another preliminary indication that the handbag approach seems to be the dominant mechanism at the energy of the experiment

Study of electron densities of normal and neoplastic human breast tissues by Compton scattering using synchrotron radiation

Energy Technology Data Exchange (ETDEWEB)

Antoniassi, M.; Conceicao, A.L.C. [Departamento de Fisica-Faculdade de Filosofia Ciencias e Letras de Ribeirao Preto-Universidade de Sao Paulo, Ribeirao Preto, Sao Paulo (Brazil); Poletti, M.E., E-mail: poletti@ffclrp.usp.br [Departamento de Fisica-Faculdade de Filosofia Ciencias e Letras de Ribeirao Preto-Universidade de Sao Paulo, Ribeirao Preto, Sao Paulo (Brazil)

2012-07-15

Electron densities of 33 samples of normal (adipose and fibroglangular) and neoplastic (benign and malignant) human breast tissues were determined through Compton scattering data using a monochromatic synchrotron radiation source and an energy dispersive detector. The area of Compton peaks was used to determine the electron densities of the samples. Adipose tissue exhibits the lowest values of electron density whereas malignant tissue the highest. The relationship with their histology was discussed. Comparison with previous results showed differences smaller than 4%. - Highlights: Black-Right-Pointing-Pointer Electron density of normal and neoplastic breast tissues was measured using Compton scattering. Black-Right-Pointing-Pointer Monochromatic synchrotron radiation was used to obtain the Compton scattering data. Black-Right-Pointing-Pointer The area of Compton peaks was used to determine the electron densities of samples. Black-Right-Pointing-Pointer Adipose tissue shows the lowest electron density values whereas the malignant tissue the highest. Black-Right-Pointing-Pointer Comparison with previous results showed differences smaller than 4%.

Study of electron densities of normal and neoplastic human breast tissues by Compton scattering using synchrotron radiation

International Nuclear Information System (INIS)

Antoniassi, M.; Conceição, A.L.C.; Poletti, M.E.

2012-01-01

Electron densities of 33 samples of normal (adipose and fibroglangular) and neoplastic (benign and malignant) human breast tissues were determined through Compton scattering data using a monochromatic synchrotron radiation source and an energy dispersive detector. The area of Compton peaks was used to determine the electron densities of the samples. Adipose tissue exhibits the lowest values of electron density whereas malignant tissue the highest. The relationship with their histology was discussed. Comparison with previous results showed differences smaller than 4%. - Highlights: ► Electron density of normal and neoplastic breast tissues was measured using Compton scattering. ► Monochromatic synchrotron radiation was used to obtain the Compton scattering data. ► The area of Compton peaks was used to determine the electron densities of samples. ► Adipose tissue shows the lowest electron density values whereas the malignant tissue the highest. ► Comparison with previous results showed differences smaller than 4%.

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

Three-dimensional imaging of flat natural and cultural heritage objects by a Compton scattering modality

Science.gov (United States)

Guerrero Prado, Patricio; Nguyen, Mai K.; Dumas, Laurent; Cohen, Serge X.

2017-01-01

Characterization and interpretation of flat ancient material objects, such as those found in archaeology, paleoenvironments, paleontology, and cultural heritage, have remained a challenging task to perform by means of conventional x-ray tomography methods due to their anisotropic morphology and flattened geometry. To overcome the limitations of the mentioned methodologies for such samples, an imaging modality based on Compton scattering is proposed in this work. Classical x-ray tomography treats Compton scattering data as noise in the image formation process, while in Compton scattering tomography the conditions are set such that Compton data become the principal image contrasting agent. Under these conditions, we are able, first, to avoid relative rotations between the sample and the imaging setup, and second, to obtain three-dimensional data even when the object is supported by a dense material by exploiting backscattered photons. Mathematically this problem is addressed by means of a conical Radon transform and its inversion. The image formation process and object reconstruction model are presented. The feasibility of this methodology is supported by numerical simulations.

On the possibility of using X-ray Compton scattering to study magnetoelectrical properties of crystals

Energy Technology Data Exchange (ETDEWEB)

Collins, S. P., E-mail: steve.collins@diamond.ac.uk; Laundy, D.; Connolley, T.; Laan, G. van der; Fabrizi, F. [Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, OX11 0DE (United Kingdom); Janssen, O. [Department of Physics, New York University, New York, NY 10003 (United States); Cooper, M. J. [Department of Physics, University of Warwick, CV4 7AL (United Kingdom); Ebert, H.; Mankovsky, S. [Universität München, Department Chemie, Haus E2.033, Butenandtstrasse 5-13, D-81377 München (Germany)

2016-02-16

The possibility of using X-ray Compton scattering to reveal antisymmetric components of the electron momentum density, as a fingerprint of magnetoelectric sample properties, is investigated experimentally and theoretically by studying the polar ferromagnet GaFeO{sub 3}. This paper discusses the possibility of using Compton scattering – an inelastic X-ray scattering process that yields a projection of the electron momentum density – to probe magnetoelectrical properties. It is shown that an antisymmetric component of the momentum density is a unique fingerprint of such time- and parity-odd physics. It is argued that polar ferromagnets are ideal candidates to demonstrate this phenomenon and the first experimental results are shown, on a single-domain crystal of GaFeO{sub 3}. The measured antisymmetric Compton profile is very small (≃ 10{sup −5} of the symmetric part) and of the same order of magnitude as the statistical errors. Relativistic first-principles simulations of the antisymmetric Compton profile are presented and it is shown that, while the effect is indeed predicted by theory, and scales with the size of the valence spin–orbit interaction, its magnitude is significantly overestimated. The paper outlines some important constraints on the properties of the antisymmetric Compton profile arising from the underlying crystallographic symmetry of the sample.

The clinical determination of absolute density in bone utilizing single and dual energy compton scattering

International Nuclear Information System (INIS)

Huddleston, A.L.; Weaver, J.

1980-01-01

Several methods important in the clinical diagnosis of skeletal diseases have been proposed for the determination of bone mass, such as photon absorptiometry, computed tomography, and neutron activation. None of these present methods provides for the determination of the physical density of bone. In the Radiological Physics Research Laboratory at the University of Virginia, the principles of Compton scattering are being investigated with the intent of determining the electron density and the physical density of human bone. A Compton-scatter densitometer has been constructed for the in vivo density determination of the femoral head. This technique utilizes of collimated low energy gamma source and detector system. The method has been tested in cadavers and in known density samples and has an accuracy of 2 %. A second densitometer has been designed for the in vivo determination of electron density of the vertebrae based upon a new technique which employs dual energy Compton scattering in the spinal column. These systems will be discussed; and the principles of dual energy Compton scatter densitometry will be presented. The importance of these isotope techniques and the feasibility of in vivo density determination in the vertebrae and femoral head will be discussed as they relate to clinical diagnosis and research. (author)

Virtual compton scattering at low energy; Diffusion compton virtuelle a basse energie

Energy Technology Data Exchange (ETDEWEB)

Lhuillier, D

1997-09-01

The work described in this PhD is a study of the Virtual Compton scattering (VCS) off the proton at low energy, below pion production threshold. Our experiment has been carried out at MAMI in the collaboration with the help of two high resolution spectrometers. Experimentally, the VCS process is the electroproduction of photons off a liquid hydrogen target. First results of data analysis including radiative corrections are presented and compared with low energy theorem prediction. VCS is an extension of the Real Compton Scattering. The virtuality of the incoming photon allows us to access new observables of the nucleon internal structure which are complementarity to the elastic form factors: the generalized polarizabilities (GP). They are function of the squared invariant mass of the virtual photo. The mass limit of these observables restore the usual electric and magnetic polarizabilities. Our experiment is the first measurement of the VCS process at a virtual photon mass equals 0.33 Ge V square. The experimental development presents the analysis method. The high precision needed in the absolute cross-section measurement required an accurate estimate of radiative corrections to the VCS. This new calculation, which has been performed in the dimensional regulation scheme, composes the theoretical part of this thesis. At low q', preliminary results agree with low energy theorem prediction. At higher q', substraction of low energy theorem contribution to extract GP is discussed. (author)

Virtual compton scattering at low energy; Diffusion compton virtuelle a basse energie

Energy Technology Data Exchange (ETDEWEB)

Lhuillier, D

1997-09-01

The work described in this PhD is a study of the Virtual Compton scattering (VCS) off the proton at low energy, below pion production threshold. Our experiment has been carried out at MAMI in the collaboration with the help of two high resolution spectrometers. Experimentally, the VCS process is the electroproduction of photons off a liquid hydrogen target. First results of data analysis including radiative corrections are presented and compared with low energy theorem prediction. VCS is an extension of the Real Compton Scattering. The virtuality of the incoming photon allows us to access new observables of the nucleon internal structure which are complementarity to the elastic form factors: the generalized polarizabilities (GP). They are function of the squared invariant mass of the virtual photo. The mass limit of these observables restore the usual electric and magnetic polarizabilities. Our experiment is the first measurement of the VCS process at a virtual photon mass equals 0.33 Ge V square. The experimental development presents the analysis method. The high precision needed in the absolute cross-section measurement required an accurate estimate of radiative corrections to the VCS. This new calculation, which has been performed in the dimensional regulation scheme, composes the theoretical part of this thesis. At low q', preliminary results agree with low energy theorem prediction. At higher q', substraction of low energy theorem contribution to extract GP is discussed. (author)

Comparative Compton scattering studies in Cu2O and Ag2O

International Nuclear Information System (INIS)

Bandyopadhyay, S.; Chatterjee, A.K.; Saha, S.K.; Chatterjee, A.

1994-01-01

Compton scattering studies in polycrystalline Cu 2 O and Ag 2 O with 59.54 keV γ radiation are reported. A comparison has been made between the valance Compton profiles of these two components scaled to lattice momentum by normalizing them to equal electron density for outer valence electrons, and this comparison shows some differences between the bonding characters of Cu 2 O and Ag 2 O. (author)

Forward Scattering of Loaded and Unloaded Antennas

DEFF Research Database (Denmark)

Gustafsson, Mats; Andersen, Jørgen Bach; Kristensson, Gerhard

2012-01-01

Forward scattering of antennas is related to antenna performance via the forward-scattering sum rule. The forward-scattering sum rule is an integral identity that shows that a weighted integral of the extinction cross section over all spectrum is proportional to the static polarizability...... of the antenna structure. Here, the forward-scattering sum rule is experimentally verified for loaded, short-circuit, and open-circuit cylindrical dipole antennas. It is also shown that the absorption efficiency cannot be greater than 1/2 for reciprocal linearly polarized lossless matched antennas...... with a symmetric radiation pattern in the forward and backward directions....

Effect of detector collimator and sample thickness on 0.662 MeV multiply Compton-scattered gamma rays

International Nuclear Information System (INIS)

Singh, Manpreet; Singh, Gurvinderjit; Sandhu, B.S.; Singh, Bhajan

2006-01-01

The simultaneous effect of detector collimator and sample thickness on 0.662 MeV multiply Compton-scattered gamma photons was studied experimentally. An intense collimated beam, obtained from 6-Ci 137 Cs source, is allowed to impinge on cylindrical aluminium samples of varying diameter and the scattered photons are detected by a 51 mmx51 mm NaI(Tl) scintillation detector placed at 90 o to the incident beam. The full energy peak corresponding to singly scattered events is reconstructed analytically. The thickness at which the multiply scattered events saturate is determined for different detector collimators. The parameters like signal-to-noise ratio and multiply scatter fraction (MSF) have also been deduced and support the work carried out by Shengli et al. [2000. EGS4 simulation of Compton scattering for nondestructive testing. KEK proceedings 200-20, Tsukuba, Japan, pp. 216-223] and Barnea et al. [1995. A study of multiple scattering background in Compton scatter imaging. NDT and E International 28, 155-162] based upon Monte Carlo calculations

Evaluation of geometrical contributions to the spread of the Compton-scatter energy distribution

International Nuclear Information System (INIS)

Hanson, A.L.; Gigante, G.E.; Dipartimento di Fisica, Universita degli Studi di Roma I, ''La Sapienza,'' Corso Vittorio Emanuele II, 244, 00186 Roma, Italy)

1989-01-01

The spectrum from Compton-scattered x rays is an inherently broad distribution. This distribution is the sum of several Gaussian-like distributions, which gives the sum its unique shape. The Gaussian-like distributions are the result of convoluting the so-called Compton profile, the spread in the scattered-x-ray energies due to the momentum distributions of the target electrons, with the detector response and the geometrical effects. The distribution is then further modified by the absorption within the sample. A formulation for both qualitatively and quantitatively determining the magnitude of the geometrical contributions is presented. This formulation is based on a recently devised approach to the scattering geometry [Hanson, Gigante, Meron, Phys. Rev. Lett. 61, 135 (1988)]. A methodology for determining the geometrical spread in the energy of the scattered x rays is presented. The results can be conveniently used to optimize scattering geometries for the reduction of the geometry-caused spread

Transverse tomography by Compton scattering scintigraphy

International Nuclear Information System (INIS)

Askienazy, S.; Lumbroso, J.; Lacaille, J.M.; Fredy, D.; Constans, J.P.; Barritault, L.

The technique of tomography by Compton-scattering was applied to the exploration of the brain. Studies were carried out on phantoms and on patients and the first results are considered highly encouraging. On a phantom skull, holes at a depth of 7 cm are visible even on analogue documents and whatever their position with regard to the bone. On patients the ventricle cavities were revealed and comparisons with gas encephalograpy showed good agreement between the two techniques. The studies on phantoms also testified to the very low dose received by the patient: about 300 mRem for 2 million counts per section [fr

On the line-shape analysis of Compton profiles and its application to neutron scattering

International Nuclear Information System (INIS)

Romanelli, G.; Krzystyniak, M.

2016-01-01

Analytical properties of Compton profiles are used in order to simplify the analysis of neutron Compton scattering experiments. In particular, the possibility to fit the difference of Compton profiles is discussed as a way to greatly decrease the level of complexity of the data treatment, making the analysis easier, faster and more robust. In the context of the novel method proposed, two mathematical models describing the shapes of differenced Compton profiles are discussed: the simple Gaussian approximation for harmonic and isotropic local potential, and an analytical Gauss–Hermite expansion for an anharmonic or anisotropic potential. The method is applied to data collected by VESUVIO spectrometer at ISIS neutron and muon pulsed source (UK) on Copper and Aluminium samples at ambient and low temperatures. - Highlights: • A new method to analyse neutron Compton scattering data is presented. • The method allows many corrections on the experimental data to be avoided. • The number of needed fitting parameters is drastically reduced using the new method. • Mass-selective analysis is facilitated with parametric studies benefiting the most. • Observables linked to anisotropic momentum distribution are obtained analytically.

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

The integration of improved Monte Carlo compton scattering algorithms into the Integrated TIGER Series

International Nuclear Information System (INIS)

Quirk, Thomas J. IV

2004-01-01

The Integrated TIGER Series (ITS) is a software package that solves coupled electron-photon transport problems. ITS performs analog photon tracking for energies between 1 keV and 1 GeV. Unlike its deterministic counterpart, the Monte Carlo calculations of ITS do not require a memory-intensive meshing of phase space; however, its solutions carry statistical variations. Reducing these variations is heavily dependent on runtime. Monte Carlo simulations must therefore be both physically accurate and computationally efficient. Compton scattering is the dominant photon interaction above 100 keV and below 5-10 MeV, with higher cutoffs occurring in lighter atoms. In its current model of Compton scattering, ITS corrects the differential Klein-Nishina cross sections (which assumes a stationary, free electron) with the incoherent scattering function, a function dependent on both the momentum transfer and the atomic number of the scattering medium. While this technique accounts for binding effects on the scattering angle, it excludes the Doppler broadening the Compton line undergoes because of the momentum distribution in each bound state. To correct for these effects, Ribbefor's relativistic impulse approximation (IA) will be employed to create scattering cross section differential in both energy and angle for each element. Using the parameterizations suggested by Brusa et al., scattered photon energies and angle can be accurately sampled at a high efficiency with minimal physical data. Two-body kinematics then dictates the electron's scattered direction and energy. Finally, the atomic ionization is relaxed via Auger emission or fluorescence. Future work will extend these improvements in incoherent scattering to compounds and to adjoint calculations.

Compton tomography system

Science.gov (United States)

Grubsky, Victor; Romanoov, Volodymyr; Shoemaker, Keith; Patton, Edward Matthew; Jannson, Tomasz

2016-02-02

A Compton tomography system comprises an x-ray source configured to produce a planar x-ray beam. The beam irradiates a slice of an object to be imaged, producing Compton-scattered x-rays. The Compton-scattered x-rays are imaged by an x-ray camera. Translation of the object with respect to the source and camera or vice versa allows three-dimensional object imaging.

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

Inverse Compton gamma-rays from pulsars

International Nuclear Information System (INIS)

Morini, M.

1983-01-01

A model is proposed for pulsar optical and gamma-ray emission where relativistic electrons beams: (i) scatter the blackbody photons from the polar cap surface giving inverse Compton gamma-rays and (ii) produce synchrotron optical photons in the light cylinder region which are then inverse Compton scattered giving other gamma-rays. The model is applied to the Vela pulsar, explaining the first gamma-ray pulse by inverse Compton scattering of synchrotron photons near the light cylinder and the second gamma-ray pulse partly by inverse Compton scattering of synchrotron photons and partly by inverse Compton scattering of the thermal blackbody photons near the star surface. (author)

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

Bistatic Forward Scattering Radar Detection and Imaging

Directory of Open Access Journals (Sweden)

Hu Cheng

2016-06-01

Full Text Available Forward Scattering Radar (FSR is a special type of bistatic radar that can implement image detection, imaging, and identification using the forward scattering signals provided by the moving targets that cross the baseline between the transmitter and receiver. Because the forward scattering effect has a vital significance in increasing the targets’ Radar Cross Section (RCS, FSR is quite advantageous for use in counter stealth detection. This paper first introduces the front line technology used in forward scattering RCS, FSR detection, and Shadow Inverse Synthetic Aperture Radar (SISAR imaging and key problems such as the statistical characteristics of forward scattering clutter, accurate parameter estimation, and multitarget discrimination are then analyzed. Subsequently, the current research progress in FSR detection and SISAR imaging are described in detail, including the theories and experiments. In addition, with reference to the BeiDou navigation satellite, the results of forward scattering experiments in civil aircraft detection are shown. Finally, this paper considers future developments in FSR target detection and imaging and presents a new, promising technique for stealth target detection.

Performance studies towards a TOF-PET sensor using Compton scattering at plastic scintillators

Science.gov (United States)

Kuramoto, M.; Nakamori, T.; Gunji, S.; Kamada, K.; Shoji, Y.; Yoshikawa, A.; Aoki, T.

2018-01-01

We have developed a sensor head for a time-of-flight (TOF) PET scanner using plastic scintillators that have a very fast timing property. Given the very small cross section of photoelectric absorption in plastic scintillators at 511 keV, we use Compton scattering in order to compensate for detection efficiency. The detector will consist of two layers of scatterers and absorbers which are made of plastic and inorganic scintillators such as GAGG:Ce, respectively. Signals are read by monolithic Multi Pixel Photon Counters, and with energy deposits and interaction time stamps are being acquired. The scintillators are built to be capable of resolving interaction position in three dimensions, so that our system has also a function of depth-of-interaction (DOI) PET scanners. TOF resolution of ~ 200 ps (FWHM) is achieved in both cases of using the leading-edge discriminator and time-walk correction and using a configuration sensitive to DOI. Both the position resolution and spectroscopy are demonstrated using the prototype data acquisition system, with Compton scattering events subsequently being obtained. We also demonstrated that the background rejection technique using the Compton cone constraint could be valid with our system.

Gamma-gamma density and lithology tools simulation based on GEANT4 advanced low energy Compton scattering (GALECS) package

International Nuclear Information System (INIS)

Esmaeili-sani, Vahid; Moussavi-zarandi, Ali; Boghrati, Behzad; Afarideh, Hossein

2012-01-01

Geophysical bore-hole data represent the physical properties of rocks, such as density and formation lithology, as a function of depth in a well. Properties of rocks are obtained from gamma ray transport logs. Transport of gamma rays, from a 137 Cs point gamma source situated in a bore-hole tool, through rock media to detectors, has been simulated using a GEANT4 radiation transport code. The advanced Compton scattering concepts were used to gain better analyses about well formation. The simulation and understanding of advanced Compton scattering highly depends on how accurately the effects of Doppler broadening and Rayleigh scattering are taken into account. A Monte Carlo package that simulates the gamma-gamma well logging tools based on GEANT4 advanced low energy Compton scattering (GALECS).

Coherent deeply virtual Compton scattering off 3He and neutron generalized parton distributions

Directory of Open Access Journals (Sweden)

Rinaldi Matteo

2014-06-01

Full Text Available It has been recently proposed to study coherent deeply virtual Compton scattering (DVCS off 3He nuclei to access neutron generalized parton distributions (GPDs. In particular, it has been shown that, in Impulse Approximation (IA and at low momentum transfer, the sum of the quark helicity conserving GPDs of 3He, H and E, is dominated by the neutron contribution. This peculiar result makes the 3He target very promising to access the neutron information. We present here the IA calculation of the spin dependent GPD H See Formula in PDF of 3He. Also for this quantity the neutron contribution is found to be the dominant one, at low momentum transfer. The known forward limit of the IA calculation of H See Formula in PDF , yielding the polarized parton distributions of 3He, is correctly recovered. The extraction of the neutron information could be anyway non trivial, so that a procedure, able to take into account the nuclear effects encoded in the IA analysis, is proposed. These calculations, essential for the evaluation of the coherent DVCS cross section asymmetries, which depend on the GPDs H,E and H See Formula in PDF , represent a crucial step for planning possible experiments at Jefferson Lab.

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

Anomalous neutron Compton scattering cross section in zirconium hydride

International Nuclear Information System (INIS)

Abdul-Redah, T.; Krzystyniak, M.; Mayers, J.; Chatzidimitriou-Dreismann, C.A.

2005-01-01

In the last few years we observed a shortfall of intensity of neutrons scattered from protons in various materials including metal hydrogen systems using neutron Compton scattering (NCS) on the VESUVIO instrument (ISIS, UK). This anomaly has been attributed to the existence of short-lived quantum entangled states of protons in these materials. Here we report on results of very recent NCS measurements on ZrH 2 at room temperature. Also here an anomalous shortfall of scattering intensity due to protons is observed. In contrast to previous experiments on NbH 0.8 , the anomalies found in ZrH 2 are independent of the scattering angle (or momentum transfer). These different results are discussed in the light of recent criticisms and experimental tests related to the data analysis procedure on VESUVIO

Study of a high finesse four mirrors Fabry Perot cavity for X-rays and Gamma rays production by laser-electron Compton scattering

International Nuclear Information System (INIS)

Fedala, Y.

2008-10-01

The main goal of this thesis is the study and design of a high finesse Fabry Perot cavity to amplify a laser beam in order to achieve power gains ranging from 10 4 to 10 5 . This cavity is dedicated to the production of intense and monochromatic X-ray for medical applications (medical RADIOTHOMX ring) and gamma rays for a Compton based polarized positron source by Compton scattering of a high power laser beam and electron beam. To increase the brightness of the Compton interaction at the collision points, it is essential to have not only a high power laser beam but also very small laser beam radii at the interaction points. To achieve such performances, 2 scenarios are possible: a concentric 2 mirrors cavity which is mechanically unstable or a 4 mirrors cavity more complex but more stable. We tested numerically mechanical stability and stability of Eigen modes polarization of various planar and non-planar geometries of 4 mirrors cavities. Experimentally, we have developed a four mirrors tetrahedral 'bow-tie' cavity; radii of the order of 20 microns were made. The Eigen modes of such a cavity, in both planar and non planar geometries, were measured and compared with the numerical results. A good agreement was observed. In a second time, the impact of Compton interaction on the transverse dynamics, in the case of the polarized positrons source, and the longitudinal dynamic, in the case of the medical ring of the electron beam was studied. Compton scattering causes energy loss and induces an additional dispersion of energy in electron beam. For the polarized positrons source, 10 collision points are planned. The transport line has been determined and the modelling of the Compton interaction effect with a simple matrix calculation was made. For the medical ring, Compton scattering causes bunch lengthening and the increase of energy dispersion which are to influence the produced X-ray flux. A study of the longitudinal dynamics of the electron beam in the ring was

Gamma-gamma density and lithology tools simulation based on GEANT4 advanced low energy Compton scattering (GALECS) package

Energy Technology Data Exchange (ETDEWEB)

Esmaeili-sani, Vahid, E-mail: vaheed_esmaeely80@yahoo.com [Department of Nuclear Engineering and Physics, Amirkabir University of Technology, P.O. Box 4155-4494, Tehran (Iran, Islamic Republic of); Moussavi-zarandi, Ali; Boghrati, Behzad; Afarideh, Hossein [Department of Nuclear Engineering and Physics, Amirkabir University of Technology, P.O. Box 4155-4494, Tehran (Iran, Islamic Republic of)

2012-02-01

Geophysical bore-hole data represent the physical properties of rocks, such as density and formation lithology, as a function of depth in a well. Properties of rocks are obtained from gamma ray transport logs. Transport of gamma rays, from a {sup 137}Cs point gamma source situated in a bore-hole tool, through rock media to detectors, has been simulated using a GEANT4 radiation transport code. The advanced Compton scattering concepts were used to gain better analyses about well formation. The simulation and understanding of advanced Compton scattering highly depends on how accurately the effects of Doppler broadening and Rayleigh scattering are taken into account. A Monte Carlo package that simulates the gamma-gamma well logging tools based on GEANT4 advanced low energy Compton scattering (GALECS).

Research building gamma Compton scattering measurement system and related exercises for training nuclear human resources

International Nuclear Information System (INIS)

Mai Xuan Phong; Nguyen Van Hung; Pham Xuan Hai; Le Van Ngoc; Nguyen Xuan Hai; Dang Lanh; Tran Quoc Duong

2013-01-01

In this subject we have designed and manufactured Compton scattering gamma measurement system based on the calculated optimal configuration as well as the conditions of protect radiation by using Monte-Carlo simulation program and fabrication with the optimal conditions were selected. Monte-Carlo simulation calculation of Compton scattering gamma follow different angles on copper, surveying gamma radiation attenuation characteristics of materials: lead, iron, aluminum, and compared with the experimental results performed on the same measurement system has been built and given for evaluation, comments. (author)

Dyson Orbitals, Quasi-Particle effects and Compton scattering

OpenAIRE

Barbiellini, B.; Bansil, A.

2004-01-01

Dyson orbitals play an important role in understanding quasi-particle effects in the correlated ground state of a many-particle system and are relevant for describing the Compton scattering cross section beyond the frameworks of the impulse approximation (IA) and the independent particle model (IPM). Here we discuss corrections to the Kohn-Sham energies due to quasi-particle effects in terms of Dyson orbitals and obtain a relatively simple local form of the exchange-correlation energy. Illust...

Accurate calculation of the differential cross section of compton scattering with electron mixed chain propagator in SM

International Nuclear Information System (INIS)

Chen Xuewen; Fang Zhenyun; Shi Chengye

2012-01-01

By using the electroweak standard model (SM), we analyzed the framework of electron mixed chain propagator which composed of serious of different physical loops participating in electroweak interaction and completed the relevant analytical calculation. Then, we obtained the analytical result of electron mixed chain propagator. By applying our result to Compton scattering, the differential cross section of Compton scattering dσ SM (chain) /dcosθ is counted accurately. This result is compared with the lowest order differential cross section dσ (tree) /dcosθ and the electronic chain propagator Compton scattering differential cross section dσ QED (chain) /dcosθ in quantum electrodynamics (QED). It can be seen that dσ SM (chain ) /dcosθ can show the radiation correction more subtly than dσ QED (chain) /dcosθ. (authors)

Energy distribution of 0. 279 MeV gamma rays Compton scattered from bound electrons

Energy Technology Data Exchange (ETDEWEB)

Singh, B; Singh, P; Singh, G; Ghumman, B S

1984-11-01

Energy and intensity distribution of 0.279 MeV gamma rays Compton scattered from K-shell electrons of tantalum is measured at scattering angle of 70deg. The experimental results are compared with the available theoretical data. Spectral distribution is also obtained as a function of scatterer thickness to account for the contribution of false events. 13 refs.

Rayleigh to Compton ratio scatter tomography applied to breast cancer diagnosis: A preliminary computational study

International Nuclear Information System (INIS)

Antoniassi, M.; Conceição, A.L.C.; Poletti, M.E.

2014-01-01

In the present work, a tomographic technique based on Rayleigh to Compton scattering ratio (R/C) was studied using computational simulation in order to assess its application to breast cancer diagnosis. In this preliminary study, some parameters that affect the image quality were evaluated, such as: (i) energy beam, (ii) size and glandularity of the breast, and (iii) statistical count noise. The results showed that the R/C contrast increases with increasing photon energy and decreases with increasing glandularity of the sample. The statistical noise showed to be a significant parameter, although the quality of the obtained images was acceptable for a considerable range of noise level. The preliminary results suggest that the R/C tomographic technique has a potential of being applied as a complementary tool in the breast cancer diagnostic. - Highlights: ► A tomographic technique based on Rayleigh to Compton scattering ratio is proposed in order to study breast tissues. ► The Rayleigh to Compton scattering ratio technique is compared with conventional transmission technique. ► The influence of experimental parameters (energy, sample, detection system) is studied

Deeply Virtual Compton Scattering off a deuterium target at the HERMES experiment

International Nuclear Information System (INIS)

Movsisyan, Aram

2011-05-01

Deeply virtual Compton scattering is studied in this report, using all data collected at the HERMES experiment from 1996 to 2005. Azimuthal asymmetries with respect to beam-helicity, beam-charge and target polarization alone and also to their different combinations for hard exclusive electroproduction of real photons in deep-inelastic scattering from a both unpolarized and longitudinally polarized deuterium targets are measured. The asymmetries are attributed to the interference between the deeply virtual Compton scattering and Bethe-Heitler processes. The asymmetries are observed in the exclusive region -(1.5) 2 GeV 2 2 X 2 GeV 2 of the squared missing mass. The dependences of these asymmetries on -t, x N , or Q 2 are investigated. The results include the coherent process ed→edγ and the incoherent process ed→epnγ where in addition a nucleon may be excited to a resonance. For an unpolarized deuterium target, the leading Fourier amplitude of the beam-helicity asymmetry that is sensitive to the interference term is found to be substantial, but no significant t dependence is observed. The leading amplitude of the beam-charge asymmetry is substantial at large -t, but becomes small at small values of -t. The amplitudes of the beam-helicity asymmetry that are sensitive to the squared DVCS term are found to be consistent with zero. The deuteron Compton form factor H 1 appears to have a similar behavior as H of the proton. (orig.)

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.

Sources of the X-rays Based on Compton Scattering

International Nuclear Information System (INIS)

Androsov, V.; Bulyak, E.; Gladkikh, P.; Karnaukhov, I.; Mytsykov, A.; Telegin, Yu.; Shcherbakov, A.; Zelinsky, A.

2007-01-01

The principles of the intense X-rays generation by laser beam scattering on a relativistic electron beam are described and description of facilities assigned to produce the X-rays based on Compton scattering is presented. The possibilities of various types of such facilities are estimated and discussed. The source of the X-rays based on a storage ring with low beam energy is described in details and advantages of the sources of such type are discussed.The results of calculation and numerical simulation carried out for laser electron storage ring NESTOR that is under development in NSC KIPT show wide prospects of the accelerator facility of such type

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

Electronic structure of the palladium hydride studied by compton scattering

CERN Document Server

Mizusaki, S; Yamaguchi, M; Hiraoka, N; Itou, M; Sakurai, Y

2003-01-01

The hydrogen-induced changes in the electronic structure of Pd have been investigated by Compton scattering experiments associated with theoretical calculations. Compton profiles (CPs) of single crystal of Pd and beta phase hydride PdH sub x (x=0.62-0.74) have been measured along the [100], [110] and [111] directions with a momentum resolution of 0.14-0.17 atomic units using 115 keV x-rays. The theoretical Compton profiles have been calculated from the wavefunctions obtained utilizing the full potential linearized augmented plane wave method within the local density approximation for Pd and stoichiometric PdH. The experimental and the theoretical results agreed well with respect to the difference in the CPs between PdH sub x and Pd, and the anisotropy in the CPs of Pd or PdH sub x. This study provides lines of evidence that upon hydride formation the lowest valance band of Pd is largely modified due to hybridization with H 1s-orbitals and the Fermi energy is raised into the sp-band. (author)

Status of Kharkov X-ray Generator based on Compton Scattering NESTOR

NARCIS (Netherlands)

Zelinsky, A.; Androsov, V.P.; Bulyak, E.V.; Drebot, I.; Gladkikh, P.I.; Grevtsev, V.; Botman, J.I.M.; Ivashchenko, V.; Karnaukhov, I.M.; Lapshin, V.I.; Markov, V.; Mocheshnikov, N.; Mytsykov, A.; Peev, F.A.; Rezaev, A.; Shcherbakov, A.; Skomorkohov, V.; Skyrda, V.; Telegin, Y.; Trotsenko, V.; Tatchyn, R.; Lebedev, B.; Agafonov, A.V.

2004-01-01

Nowadays the sources of the X-rays based on a storage ring with low beam energy and Compton scattering of intense laser beam are under development in several laboratories. In the paper the state-of-art in development and construction of cooperative project of a Kharkov advanced X-ray source NESTOR

Deeply virtual Compton scattering: How to test handbag dominance?

International Nuclear Information System (INIS)

Gousset, T.; Gousset, T.; Diehl, M.; Pire, B.; Diehl, M.; Ralston, J.P.

1998-01-01

We propose detailed tests of the handbag approximation in exclusive deeply virtual Compton scattering. Those tests make no use of any prejudice about parton correlations in the proton which are basically unknown objects and beyond the scope of perturbative QCD. Since important information on the proton substructure can be gained in the regime of light cone dominance we consider that such a class of tests is of special relevance. copyright 1998 American Institute of Physics

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.)

Transmission characteristics of the kinematics of the laser-plasma shock wave in air in compton scattering

International Nuclear Information System (INIS)

Hao Dongshan; Xie Hongjun

2006-01-01

By comparing the kinematical equation of a shock wave in free air, the study of transmission characteristics of the laser plasma shock wave in Compton scattering is presented. The results show that the attenuation course of the kinematics of he laser plasma shock wave is related not only with the explosion fountainhead and the characteristics of the explosion course, total energy release, air elastic, but also with multi-photon nonlinear Compton scattering. Because of the scattering the initial radius of the shock wave increases, the attenuation course shortens, the energy metastasis efficiency rises. The results of the numerical analysis and the actual values of the shock waves in air by a way intense explosion are very tallying. (authors)

Complete $O(\\alpha)$ QED corrections to polarized Compton scattering

CERN Document Server

Denner, Ansgar

1999-01-01

The complete QED corrections of O(alpha) to polarized Compton scattering are calculated for finite electron mass and including the real corrections induced by the processes e^- gamma -> e^- gamma gamma and e^- gamma -> e^- e^- e^+. All relevant formulas are listed in a form that is well suited for a direct implementation in computer codes. We present a detailed numerical discussion of the O(alpha)-corrected cross section and the left-right asymmetry in the energy range of present and future Compton polarimeters, which are used to determine the beam polarization of high-energetic e^+- beams. For photons with energies of a few eV and electrons with SLC energies or smaller, the corrections are of the order of a few per mille. In the energy range of future e^+e^- colliders, however, they reach 1-2% and cannot be neglected in a precision polarization measurement.

Compton scattering by mesons in nuclei: Experiment on 208Pb

International Nuclear Information System (INIS)

Fuhrberg, K.; Martin, G.; Haeger, D.; Ludwig, M.; Schumacher, M.; Andersson, B.E.; Blomqvist, K.I.; Ruijter, H.; Sandell, A.; Schroeder, B.; Hayward, E.; Nilsson, L.; Zorro, R.

1992-01-01

Using 58 and 73 MeV tagged photons and scattering angles from 60deg to 150deg, it is shown that is possible to observe Compton scattering by 'mesons in nuclei ' through an incomplete cancellation of the mesonic (exchange- current) seagull amplitude by parts of the nuclear resonance amplitude related to the giant-dipole resonance of 208 Pb. This phenomenon is a property of an extended nucleus and , therefore, cannot be dtudied on the deuteron. Predictions of the exchange form factor which determines the angular distribution of the exchange seagull amplitude are compared with experimental data. (orig.)

Compton scattering from nuclei and photo-absorption sum rules

International Nuclear Information System (INIS)

Gorchtein, Mikhail; Hobbs, Timothy; Londergan, J. Timothy; Szczepaniak, Adam P.

2011-01-01

We revisit the photo-absorption sum rule for real Compton scattering from the proton and from nuclear targets. In analogy with the Thomas-Reiche-Kuhn sum rule appropriate at low energies, we propose a new 'constituent quark model' sum rule that relates the integrated strength of hadronic resonances to the scattering amplitude on constituent quarks. We study the constituent quark model sum rule for several nuclear targets. In addition, we extract the α=0 pole contribution for both proton and nuclei. Using the modern high-energy proton data, we find that the α=0 pole contribution differs significantly from the Thomson term, in contrast with the original findings by Damashek and Gilman.

Measurement of Deeply Virtual Compton Scattering at HERA

CERN Document Server

Adloff, C.; Andrieu, B.; Anthonis, T.; Arkadov, V.; Astvatsatourov, A.; Babaev, A.; Bahr, J.; Baranov, P.; Barrelet, E.; Bartel, W.; Bate, P.; Beglarian, A.; Behnke, O.; Beier, C.; Belousov, A.; Benisch, T.; Berger, Christoph; Berndt, T.; Bizot, J.C.; Boudry, V.; Braunschweig, W.; Brisson, V.; Broker, H.B.; Brown, D.P.; Bruckner, W.; Bruncko, D.; Burger, J.; Busser, F.W.; Bunyatyan, A.; Burrage, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Cao, Jun; Caron, S.; Clarke, D.; Clerbaux, B.; Collard, C.; Contreras, J.G.; Coppens, Y.R.; Coughlan, J.A.; Cousinou, M.C.; Cox, B.E.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Dau, W.D.; Daum, K.; Davidsson, M.; Delcourt, B.; Delerue, N.; Demirchyan, R.; De Roeck, A.; De Wolf, E.A.; Diaconu, C.; Dingfelder, J.; Dixon, P.; Dodonov, V.; Dowell, J.D.; Droutskoi, A.; Dubak, A.; Duprel, C.; Eckerlin, Guenter; Eckstein, D.; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Eisenhandler, E.; Ellerbrock, M.; Elsen, E.; Erdmann, M.; Erdmann, W.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Ferencei, J.; Ferron, S.; Fleischer, M.; Fleming, Y.H.; Flugge, G.; Fomenko, A.; Foresti, I.; Formanek, J.; Foster, J.M.; Franke, G.; Gabathuler, E.; Gabathuler, K.; Garvey, J.; Gassner, J.; Gayler, Joerg; Gerhards, R.; Gerlich, C.; Ghazaryan, Samvel; Goerlich, L.; Gogitidze, N.; Goldberg, M.; Goodwin, C.; Grab, C.; Grassler, H.; Greenshaw, T.; Grindhammer, Guenter; Hadig, T.; Haidt, D.; Hajduk, L.; Haynes, W.J.; Heinemann, B.; Heinzelmann, G.; Henderson, R.C.W.; Hengstmann, S.; Henschel, H.; Heremans, R.; Herrera, G.; Herynek, I.; Hildebrandt, M.; Hilgers, M.; Hiller, K.H.; Hladky, J.; Hoting, P.; Hoffmann, D.; Horisberger, R.; Hurling, S.; Ibbotson, M.; Issever, C .; Jacquet, M.; Jaffre, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jones, M.A.S.; Jung, H.; Kastli, H.K.; Kant, D.; Kapichine, M.; Karlsson, M.; Karschnick, O.; Keil, F.; Keller, N.; Kennedy, J.; Kenyon, I.R.; Kermiche, S.; Kiesling, Christian M.; Kjellberg, P.; Klein, M.; Kleinwort, C.; Kluge, T.; Knies, G.; Koblitz, B.; Kolya, S.D.; Korbel, V.; Kostka, P.; Kotelnikov, S.K.; Koutouev, R.; Koutov, A.; Krehbiel, H.; Kroseberg, J.; Kruger, K.; Kupper, A.; Kuhr, T.; Kurca, T.; Lahmann, R.; Lamb, D.; Landon, M.P.J.; Lange, W.; Lastovicka, T.; Laycock, P.; Lebailly, E.; Lebedev, A.; Leissner, B.; Lemrani, R.; Lendermann, V.; Levonian, S.; Lindstroem, M.; List, B.; Lobodzinska, E.; Lobodzinski, B.; Loginov, A.; Loktionova, N.; Lubimov, V.; Luders, S.; Luke, D.; Lytkin, L.; Mahlke-Kruger, H.; Malden, N.; Malinovski, E.; Malinovski, I.; Maracek, R.; Marage, P.; Marks, J.; Marshall, R.; Martyn, H.U.; Martyniak, J.; Maxfield, S.J.; Meer, D.; Mehta, A.; Meier, K.; Meyer, A.B.; Meyer, H.; Meyer, J.; Meyer, P.O.; Mikocki, S.; Milstead, D.; Mkrtchyan, T.; Mohr, R.; Mohrdieck, S.; Mondragon, M.N.; Moreau, F.; Morozov, A.; Morris, J.V.; Muller, K.; Murin, P.; Nagovizin, V.; Naroska, B.; Naumann, J.; Naumann, T.; Nellen, G.; Newman, Paul R.; Nicholls, T.C.; Niebergall, F.; Niebuhr, C.; Nix, O.; Nowak, G.; Olsson, J.E.; Ozerov, D.; Panassik, V.; Pascaud, C.; Patel, G.D.; Peez, M.; Perez, E.; Phillips, J.P.; Pitzl, D.; Poschl, R.; Potachnikova, I.; Povh, B.; Rabbertz, K.; Radel, G.; Rauschenberger, J.; Reimer, P.; Reisert, B.; Reyna, D.; Risler, C.; Rizvi, E.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Rusakov, S.; Rybicki, K.; Sankey, D.P.C.; Scheins, J.; Schilling, F.P.; Schleper, P.; Schmidt, D.; Schmidt, S.; Schmitt, S.; Schneider, M.; Schoeffel, L.; Schoning, A.; Schorner, T.; Schroder, V.; Schultz-Coulon, H.C.; Schwanenberger, C.; Sedlak, K.; Sefkow, F.; Chekelian, V.; Sheviakov, I.; Shtarkov, L.N.; Sirois, Y.; Sloan, T.; Smirnov, P.; Solovev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Spitzer, H.; Stamen, R.; Stella, B.; Stiewe, J.; Straumann, U.; Swart, M.; Tasevsky, M.; Chernyshov, V.; Chetchelnitski, S.; Thompson, Graham; Thompson, P.D.; Tobien, N.; Traynor, D.; Truoel, Peter; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Turney, J.E.; Tzamariudaki, E.; Udluft, S.; Urban, Marcel; Usik, A.; Valkar, S.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vassilev, S.; Vazdik, Y.; Vichnevski, A.; Wacker, K.; Wallny, R.; Waugh, B.; Weber, G.; Weber, M.; Wegener, D.; Werner, C.; Werner, M.; Werner, N.; White, G.; Wiesand, S.; Wilksen, T.; Winde, M.; Winter, G.G.; Wissing, C.; Wobisch, M.; Wunsch, E.; Wyatt, A.C.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zomer, F.; Zsembery, J.; zur Nedden, M.

2001-01-01

A measurement is presented of elastic Deeply Virtual Compton Scattering e^+ + p -> e^+ + photon + p at HERA using data taken with the H1 detector. The cross section is measured as a function of the photon virtuality, Q^2, and the invariant mass, W, of the gamma p system, in the kinematic range 2 < Q^2 < 20 GeV^2, 30 < W < 120 GeV and |t| < 1 GeV^2, where t is the squared momentum transfer to the proton. The measurement is compared to QCD based calculations.

Kharkov X-ray Generator Based On Compton Scattering

International Nuclear Information System (INIS)

Shcherbakov, A.; Zelinsky, A.; Mytsykov, A.; Gladkikh, P.; Karnaukhov, I.; Lapshin, V.; Telegin, Y.; Androsov, V.; Bulyak, E.; Botman, J.I.M.; Tatchyn, R.; Lebedev, A.

2004-01-01

Nowadays X-ray sources based on storage rings with low beam energy and Compton scattering of intense laser beams are under development in several laboratories. An international cooperative project of an advanced X-ray source of this type at the Kharkov Institute of Physics and Technology (KIPT) is described. The status of the project is reviewed. The design lattice of the storage ring and calculated X-ray beam parameters are presented. The results of numerical simulation carried out for proposed facility show a peak spectral X-ray intensity of about 1014 can be produced

Deeply Virtual Compton Scattering off a deuterium target at the HERMES experiment

Energy Technology Data Exchange (ETDEWEB)

Movsisyan, Aram

2011-05-15

Deeply virtual Compton scattering is studied in this report, using all data collected at the HERMES experiment from 1996 to 2005. Azimuthal asymmetries with respect to beam-helicity, beam-charge and target polarization alone and also to their different combinations for hard exclusive electroproduction of real photons in deep-inelastic scattering from a both unpolarized and longitudinally polarized deuterium targets are measured. The asymmetries are attributed to the interference between the deeply virtual Compton scattering and Bethe-Heitler processes. The asymmetries are observed in the exclusive region -(1.5){sup 2} GeV{sup 2}Compton form factor H{sub 1} appears to have a similar behavior as H of the proton. (orig.)

EXTERNAL COMPTON SCATTERING IN BLAZAR JETS AND THE LOCATION OF THE GAMMA-RAY EMITTING REGION

Energy Technology Data Exchange (ETDEWEB)

Finke, Justin D., E-mail: justin.finke@nrl.navy.mil [U.S. Naval Research Laboratory, Code 7653, 4555 Overlook Ave. SW, Washington, DC, 20375-5352 (United States)

2016-10-20

I study the location of the γ -ray emission in blazar jets by creating a Compton-scattering approximation that is valid for all anisotropic radiation fields in the Thomson through Klein–Nishina regimes, is highly accurate, and can speed up numerical calculations by up to a factor of ∼10. I apply this approximation to synchrotron self-Compton, external Compton scattering of photons from the accretion disk, broad line region (BLR), and dust torus. I use a stratified BLR model and include detailed Compton-scattering calculations of a spherical and flattened BLR. I create two dust torus models, one where the torus is an annulus and one where it is an extended disk. I present detailed calculations of the photoabsorption optical depth using my detailed BLR and dust torus models, including the full angle dependence. I apply these calculations to the emission from a relativistically moving blob traveling through these radiation fields. The ratio of γ -ray to optical flux produces a predictable pattern that could help locate the γ -ray emission region. I show that the bright flare from 3C 454.3 in 2010 November detected by the Fermi Large Area Telescope is unlikely to originate from a single blob inside the BLR. This is because it moves outside the BLR in a time shorter than the flare duration, although emission by multiple blobs inside the BLR is possible. Also, γ -rays are unlikely to originate from outside of the BLR, due to the scattering of photons from an extended dust torus, since the cooling timescale would be too long to explain the observed short variability.

Compton radiography, 2

International Nuclear Information System (INIS)

Okuyama, Shinichi; Sera, Koichiro; Fukuda, Hiroshi; Shishido, Fumio; Mishina, Hitoshi.

1977-01-01

Compton radiography, a tomographic technic with Compton-scattered rays of a monochromatic gamma ray beam, was feasible of tomographing a chest phantom. The result suggested that the technic could be extended to imaging of the lung and the surrounding structures of the chest wall, mediastinum and liver in Compton tomographic mode. (auth.)

The Mathematical Foundations of 3D Compton Scatter Emission Imaging

Directory of Open Access Journals (Sweden)

T. T. Truong

2007-01-01

Full Text Available The mathematical principles of tomographic imaging using detected (unscattered X- or gamma-rays are based on the two-dimensional Radon transform and many of its variants. In this paper, we show that two new generalizations, called conical Radon transforms, are related to three-dimensional imaging processes based on detected Compton scattered radiation. The first class of conical Radon transform has been introduced recently to support imaging principles of collimated detector systems. The second class is new and is closely related to the Compton camera imaging principles and invertible under special conditions. As they are poised to play a major role in future designs of biomedical imaging systems, we present an account of their most important properties which may be relevant for active researchers in the field.

Non-Proportionality of Electron Response and Energy Resolution of Compton Electrons in Scintillators

Science.gov (United States)

Swiderski, L.; Marcinkowski, R.; Szawlowski, M.; Moszynski, M.; Czarnacki, W.; Syntfeld-Kazuch, A.; Szczesniak, T.; Pausch, G.; Plettner, C.; Roemer, K.

2012-02-01

Non-proportionality of light yield and energy resolution of Compton electrons in three scintillators (LaBr3:Ce, LYSO:Ce and CsI:Tl) were studied in a wide energy range from 10 keV up to 1 MeV. The experimental setup was comprised of a High Purity Germanium detector and tested scintillators coupled to a photomultiplier. Probing the non-proportionality and energy resolution curves at different energies was obtained by changing the position of various radioactive sources with respect to both detectors. The distance between both detectors and source was kept small to make use of Wide Angle Compton Coincidence (WACC) technique, which allowed us to scan large range of scattering angles simultaneously and obtain relatively high coincidence rate of 100 cps using weak sources of about 10 μCi activity. The results are compared with those obtained by direct irradiation of the tested scintillators with gamma-ray sources and fitting the full-energy peaks.

Compton scattering of microwave background radiation by gas in galaxy clusters

International Nuclear Information System (INIS)

Gould, R.J.; Rephaeli, Y.

1978-01-01

Based on data on the X-ray spectrum of the Coma cluster, interpreted as thermal bremsstrahlung, the expected brightness depletion from Compton scattering of the microwave background in the direction of the cluster is computed. The calculated depletion is about one-third that recently observed by Gull and Northover, and the discrepancy is discussed. In comparing the observed microwave depletion in the direction of other clusters which are X-ray sources it is found that there is no correlation with the cluster X-ray luminosity, while a dependence proportional to L/sub x//sup 1/2/ is expected. Consequently, the microwave depletion observations cannot yet be taken as good evidence for a thermal bremsstrahlung origin for the X-ray emission. The perturbation from Compton scattering of photons on the high-frequency (Wien) tail of the blackbody distribution is computed and found to be much larger than predicted in previous calculations. In the Wien tail the effect is a relative increase in the blackbody intensity that is appreciably greater in magnitude than the depletion in the Rayleigh-Jeans domain

Simulation of inverse Compton scattering and its implications on the scattered linewidth

Science.gov (United States)

Ranjan, N.; Terzić, B.; Krafft, G. A.; Petrillo, V.; Drebot, I.; Serafini, L.

2018-03-01

Rising interest in inverse Compton sources has increased the need for efficient models that properly quantify the behavior of scattered radiation given a set of interaction parameters. The current state-of-the-art simulations rely on Monte Carlo-based methods, which, while properly expressing scattering behavior in high-probability regions of the produced spectra, may not correctly simulate such behavior in low-probability regions (e.g. tails of spectra). Moreover, sampling may take an inordinate amount of time for the desired accuracy to be achieved. In this paper, we present an analytic derivation of the expression describing the scattered radiation linewidth and propose a model to describe the effects of horizontal and vertical emittance on the properties of the scattered radiation. We also present an improved version of the code initially reported in Krafft et al. [Phys. Rev. Accel. Beams 19, 121302 (2016), 10.1103/PhysRevAccelBeams.19.121302], that can perform the same simulations as those present in cain and give accurate results in low-probability regions by integrating over the emissions of the electrons. Finally, we use these codes to carry out simulations that closely verify the behavior predicted by the analytically derived scaling law.

Detection of inverse Compton scattering in plasma wakefield experiments

Energy Technology Data Exchange (ETDEWEB)

Bohlen, Simon

2016-12-15

Inverse Compton scattering (ICS) is the process of scattering of photons and electrons, where the photons gain a part of the electrons energy. In combination with plasma wakefield acceleration (PWA), ICS offers a compact MeV γ-ray source. A numerical study of ICS radiation produced in PWA experiments at FLASHForward was performed, using an ICS simulation code and the results from particle-in-cell modelling. The possibility of determining electron beam properties from measurements of the γ-ray source was explored for a wide range of experimental conditions. It was found that information about the electron divergence, the electron spectrum and longitudinal information can be obtained from measurements of the ICS beams for some cases. For the measurement of the ICS profile at FLASHForward, a CsI(Tl) scintillator array was chosen, similar to scintillators used in other ICS experiments. To find a suitable detector for spectrum measurements, an experimental test of a Compton spectrometer at the RAL was conducted. This test showed that a similar spectrometer could also be used at FLASHForward. However, changes to the spectrometer could be needed in order to use the pair production effect. In addition, further studies using Geant4 could lead to a better reconstruction of the obtained data. The studies presented here show that ICS is a promising method to analyse electron parameters from PWA experiments in further detail.

Compton scattering study of electron momentum distribution in lithium fluoride using 662 keV gamma radiations

Science.gov (United States)

Vijayakumar, R.; Shivaramu; Ramamurthy, N.; Ford, M. J.

2008-12-01

Here we report the first ever 137Cs Compton spectroscopy study of lithium fluoride. The spherical average Compton profiles of lithium fluoride are deduced from Compton scattering measurements on poly crystalline sample at gamma ray energy of 662 keV. To compare the experimental data, we have computed the spherical average Compton profiles using self-consistent Hartree-Fock wave functions employed on linear combination of atomic orbital (HF-LCAO) approximation. The directional Compton profiles and their anisotropic effects are also calculated using the same HF-LCAO approximation. The experimental spherical average profiles are found to be in good agreement with the corresponding HF-LCAO calculations and in qualitative agreement with Hartree-Fock free atom values. The present experimental isotropic and calculated directional profiles are also compared with the available experimental isotropic and directional Compton profiles using 59.54 and 159 keV γ-rays.

Optimal sum rules inequalities for spin 1/2 Compton scattering

International Nuclear Information System (INIS)

Guiasu, I.; Radescu, E.E.; Razillier, I.

1979-08-01

A formalism appropriate for model independent dispersion theoretic investigations of the (not necessarily forward) Compton scattering off spin 1/2 hadronic targets, which fully exploits the analyticity properties of the amplitudes (to lowest order in electromagnetism) in ν 2 at fixed t(ν=(s-u)/4) s,t,u = Mandelstam variables), is developed. It relies on methods which are specific to boundary value problems for analytic matrix-valued functions. An analytic factorization of the positive definite hermitian matrix associated with the bilinear expression of the unpolarized differential cross section (u.d.c.s.) in terms of the Bardeen-Tung (B.T.) invariant amplitudes is explicitly obtained. For t in a specified portion of the physical region, six new amplitudes describing the process are thereby constructed which have the same good analyticity structure in ν 2 as the (crossing symmetrized) B.T. amplitudes, while their connection with the usual helicity amplitudes is given by a matrix which is unitary on the unitarity cut. A bound on a certain integral over the u.d.c.s. above the first inelastic threshold, established in terms of the target's charge and anomalous magnetic moment, improves a previous weaker result, being now optimal under the information accepted as known. (author)

On the distribution of electrons in the double ionization of helium-like ions by Compton scattering

Energy Technology Data Exchange (ETDEWEB)

Amusia, M Ya [Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel); Drukarev, E G [Petersburg Nuclear Physics Institute, Gatchina, St Petersburg 188300 (Russian Federation)

2003-06-28

The Compton scattering of a high energy photon by a helium-like ion, followed by the ionization of two electrons, is considered outside of the Bethe surface of Compton scattering with the knock-out of a single electron. The role of shake-off (SO), of final state interactions (FSI) and of the quasi-free mechanism (QFM) is analysed. The triple and double differential distributions are calculated. It is demonstrated for the first time that in certain kinematical regions the process is dominated by the FSI and by the QFM, while the SO contribution is much smaller.

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.

A non-destructive scattering technique for investigation of pulmonary edema

International Nuclear Information System (INIS)

Sharma, Amandeep; Singh, Bhajan; Sandhu, B.S.

2012-01-01

In many biomedical studies, the density of a biological system is of great importance to investigate its structure or functioning. In the present work, for the density measurement of lung phantom, the scattering of 59.54 and 662 keV gamma photons are studied using HPGe and NaI(Tl) detectors, respectively. Phantoms simulating lung density are prepared by mixing appropriate amount of saw dust and distilled water. The regression lines, obtained from experimental data of scattered spectra, provide the amount of excessive water storage in lungs, hence the technique has the potential for a measure of pathological state like pulmonary edema. The technique is quite sensitive for small change (∼23 Kg m −3 ) in the density of lung phantom. Also, Compton scatter profile measurements (in case of 59.54 keV) results that the technique is less sensitive beyond chest wall thickness of ∼26 mm due to overlying scatter components in the measured spectrum. A portable non-invasive system described presently may be used for various industrial applications also. - Highlights: ► Measurements specify the pathological state like pulmonary edema. ► Rayleigh to Compton ratio, Wing ratio and Compton profile authenticate the results. ► The radiation dose available to chest will be lesser in comparison to chest X-ray. ► Portable system can be used for density measurements in industrial applications.

Timelike Compton scattering off the neutron and generalized parton distributions

Energy Technology Data Exchange (ETDEWEB)

Boer, M.; Guidal, M. [CNRS-IN2P3, Universite Paris-Sud, Institut de Physique Nucleaire d' Orsay, Orsay (France); Vanderhaeghen, M. [Johannes Gutenberg Universitaet, Institut fuer Kernphysik and PRISMA Cluster of Excellence, Mainz (Germany)

2016-02-15

We study the exclusive photoproduction of an electron-positron pair on a neutron target in the Jefferson Lab energy domain. The reaction consists of two processes: the Bethe-Heitler and the Timelike Compton Scattering. The latter process provides potentially access to the Generalized Parton Distributions (GPDs) of the nucleon. We calculate all the unpolarized, single- and double-spin observables of the reaction and study their sensitivities to GPDs. (orig.)

Experimental test of Bell's inequalities using angular correlation of compton-scattered annihilation photons

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

Compton radiography, 2. Clinical significance of Compton radiography of a chest phantom

Energy Technology Data Exchange (ETDEWEB)

Okuyama, S; Sera, K; Fukuda, H; Shishido, F [Tohoku Univ., Sendai (Japan). Research Inst. for Tuberculosis, Leprosy and Cancer; Mishina, H

1977-09-01

Compton radiography, a tomographic technic with Compton-scattered rays of a monochromatic gamma ray beam, was feasible of tomographing a chest phantom. The result suggested that the technic could be extended to imaging of the lung and the surrounding structures of the chest wall, mediastinum and liver in Compton tomographic mode.

Deuteron Compton scattering below pion photoproduction threshold

Science.gov (United States)

Levchuk, M. I.; L'vov, A. I.

2000-07-01

Deuteron Compton scattering below pion photoproduction threshold is considered in the framework of the nonrelativistic diagrammatic approach with the Bonn OBE potential. A complete gauge-invariant set of diagrams is taken into account which includes resonance diagrams without and with NN-rescattering and diagrams with one- and two-body seagulls. The seagull operators are analyzed in detail, and their relations with free- and bound-nucleon polarizabilities are discussed. It is found that both dipole and higher-order polarizabilities of the nucleon are required for a quantitative description of recent experimental data. An estimate of the isospin-averaged dipole electromagnetic polarizabilities of the nucleon and the polarizabilities of the neutron is obtained from the data.

Deuteron Compton scattering below pion photoproduction threshold

International Nuclear Information System (INIS)

Levchuk, M.I.; L'vov, A.I.

2000-01-01

Deuteron Compton scattering below pion photoproduction threshold is considered in the framework of the nonrelativistic diagrammatic approach with the Bonn OBE potential. A complete gauge-invariant set of diagrams is taken into account which includes resonance diagrams without and with NN-rescattering and diagrams with one- and two-body seagulls. The seagull operators are analyzed in detail, and their relations with free- and bound-nucleon polarizabilities are discussed. It is found that both dipole and higher-order polarizabilities of the nucleon are required for a quantitative description of recent experimental data. An estimate of the isospin-averaged dipole electromagnetic polarizabilities of the nucleon and the polarizabilities of the neutron is obtained from the data

Deuteron Compton scattering below pion photoproduction threshold

Energy Technology Data Exchange (ETDEWEB)

Levchuk, M.I. E-mail: levchuk@dragon.bas-net.by; L' vov, A.I. E-mail: lvov@x4u.lebedev.ru

2000-07-17

Deuteron Compton scattering below pion photoproduction threshold is considered in the framework of the nonrelativistic diagrammatic approach with the Bonn OBE potential. A complete gauge-invariant set of diagrams is taken into account which includes resonance diagrams without and with NN-rescattering and diagrams with one- and two-body seagulls. The seagull operators are analyzed in detail, and their relations with free- and bound-nucleon polarizabilities are discussed. It is found that both dipole and higher-order polarizabilities of the nucleon are required for a quantitative description of recent experimental data. An estimate of the isospin-averaged dipole electromagnetic polarizabilities of the nucleon and the polarizabilities of the neutron is obtained from the data.

Dynamic measurement of forward scattering

DEFF Research Database (Denmark)

Appel-Hansen, Jørgen; Rusch, W.

1975-01-01

A dynamic method for the measurement of forward scattering in a radio anechoic chamber is described. The quantity determined is the induced-field-ratio (IFR) of conducting cylinders. The determination of the IFR is highly sensitive to 1) multiple scattering between the cylinder and the obpring...

X-ray Compton line scan tomography

Energy Technology Data Exchange (ETDEWEB)

Kupsch, Andreas; Lange, Axel; Jaenisch, Gerd-Ruediger [Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin (Germany). Fachgruppe 8.5 - Mikro-ZfP; Hentschel, Manfred P. [Technische Univ. Berlin (Germany); Kardjilov, Nikolay; Markoetter, Henning; Hilger, Andre; Manke, Ingo [Helmholtz-Zentrum Berlin (HZB) (Germany); Toetzke, Christian [Potsdam Univ. (Germany)

2015-07-01

The potentials of incoherent X-ray scattering (Compton) computed tomography (CT) are investigated. The imaging of materials of very different atomic number or density at once is generally a perpetual challenge for X-ray tomography or radiography. In a basic laboratory set-up for simultaneous perpendicular Compton scattering and direct beam attenuation tomography are conducted by single channel photon counting line scans. This results in asymmetric distortions of the projection profiles of the scattering CT data set. In a first approach, corrections of Compton scattering data by taking advantage of rotational symmetry yield tomograms without major geometric artefacts. A cylindrical sample composed of PE, PA, PVC, glass and wood demonstrates similar Compton contrast for all the substances, while the conventional absorption tomogram only reveals the two high order materials. Comparison to neutron tomography reveals astonishing similarities except for the glass component (without hydrogen). Therefore, Compton CT offers the potential to replace neutron tomography, which requires much more efforts.

A Glimpse of Gluons through Deeply Virtual Compton Scattering on the Proton

OpenAIRE

Defurne, M.; Jiménez-Argüello, A. Martì; Ahmed, Z.; Albataineh, H.; Allada, K.; Aniol, K. A.; Bellini, V.; Benali, M.; Boeglin, W.; Bertin, P.; Brossard, M.; Camsonne, A.; Canan, M.; Chandavar, S.; Chen, C.

2017-01-01

The proton is composed of quarks and gluons, bound by the most elusive mechanism of strong interaction called confinement. In this work, the dynamics of quarks and gluons are investigated using deeply virtual Compton scattering (DVCS): produced by a multi-GeV electron, a highly virtual photon scatters off the proton which subsequently radiates a high energy photon. Similarly to holography, measuring not only the magnitude but also the phase of the DVCS amplitude allows to perform 3D images of...

Detection of detachments and inhomogeneities in frescos by Compton scattering

International Nuclear Information System (INIS)

Castellano, A.; Cesareo, R.; Buccolieri, G.; Donativi, M.; Palama, F.; Quarta, S.; De Nunzio, G.; Brunetti, A.; Marabelli, M.; Santamaria, U.

2005-01-01

A mobile instrument has been developed for the detection and mapping of detachments in frescos by using Compton back scattered photons. The instrument is mainly composed of a high energy X-ray tube, an X-ray detection system and a translation table. The instrument was first applied to samples simulating various detachment situations, and then transferred to the Vatican Museum to detect detachments and inhomogeneities in the stanza di Eliodoro, one of the 'Raphael's stanze'

Low-energy theorems for Compton scattering up to order e/sup 4/. [Scattering amplitudes dispersion relations

Energy Technology Data Exchange (ETDEWEB)

Pippig, G

1975-01-01

Taking the Compton scattering of pions and deuterons as an example it is shown that low-energy theorems which are valid for the order e/sup 2/ are also valid for the next higher order of electromagnetic interactions. The imaginary component of the scattering amplitude was exactly calculated for the energy of incident photons in the order e/sup 4/ up to the desired one, whereas the real component was obtained from dispersion relations. It is proved that the results derived from the dispersion theory of strong interactions are equivalent to those obtained from quantum electrodynamics for spin 0 and spin 1, respectively.

Quasi-free Compton scattering and the polarizabilities of the neutron

International Nuclear Information System (INIS)

Kossert, K.; Camen, M.; Wissmann, F.; Schumacher, M.; Seitz, B.; Ahrens, J.; Arends, H.J.; Beck, R.; Caselotti, G.; Jahn, O.; Jennewein, P.; Olmos de Leon, V.; Annand, J.R.M.; McGeorge, J.C.; Rosner, G.; Grabmayr, P.; Natter, A.; Levchuk, M.I.; L'vov, A.I.; Petrun'kin, V.A.; Smend, F.; Thomas, A.; Weihofen, W.; Zapadtka, F.

2003-01-01

Differential cross-sections for quasi-free Compton scattering from the proton and neutron bound in the deuteron have been measured using the Glasgow/Mainz photon tagging spectrometer at the Mainz MAMI accelerator together with the Mainz 48cm diameter x 64cm NaI(Tl) photon detector and the Goettingen SENECA recoil detector. The data cover photon energies ranging from 200MeV to 400MeV at θ LAB γ =136.2 . Liquid deuterium and hydrogen targets allowed direct comparison of free and quasi-free scattering from the proton. The neutron detection efficiency of the SENECA detector was measured via the reaction p(γ,π + n). The ''free'' proton Compton scattering cross-sections extracted from the bound proton data are in reasonable agreement with those for the free proton which gives confidence in the method to extract the differential cross-section for free scattering from quasi-free data. Differential cross-sections on the free neutron have been extracted and the difference of the electromagnetic polarizabilities of the neutron has been determined to be α n -β n =9.8±3.6(stat) +2.1 -1.1 (syst)±2.2(model) in units of 10 -4 fm 3 . In combination with the polarizability sum α n +β n =15.2±0.5 deduced from photoabsorption data, the neutron electric and magnetic polarizabilities, α n =12.5±1.8(stat) + 1 .1 -0.6 (syst)±1.1(model) and β n =2.7±1.8(stat) +0.6 -1.1 (syst)±1.1(model) are obtained. The backward spin polarizability of the neutron was determined to be γ (n) π =(58.6±4.0) x 10 -4 fm 4 . (orig.)

Scattering theory of space-time non-commutative abelian gauge field theory

International Nuclear Information System (INIS)

Rim, Chaiho; Yee, Jaehyung

2005-01-01

The unitary S-matrix for space-time non-commutative quantum electrodynamics is constructed using the *-time ordering which is needed in the presence of derivative interactions. Based on this S-matrix, we formulate the perturbation theory and present the Feynman rule. We then apply this perturbation analysis to the Compton scattering process to the lowest order and check the gauge invariance of the scattering amplitude at this order.

A didactic experiment showing the Compton scattering by means of a clinical gamma camera.

Science.gov (United States)

Amato, Ernesto; Auditore, Lucrezia; Campennì, Alfredo; Minutoli, Fabio; Cucinotta, Mariapaola; Sindoni, Alessandro; Baldari, Sergio

2017-06-01

We describe a didactic approach aimed to explain the effect of Compton scattering in nuclear medicine imaging, exploiting the comparison of a didactic experiment with a gamma camera with the outcomes from a Monte Carlo simulation of the same experimental apparatus. We employed a 99m Tc source emitting 140.5keV photons, collimated in the upper direction through two pinholes, shielded by 6mm of lead. An aluminium cylinder was placed on the source at 50mm of distance. The energy of the scattered photons was measured on the spectra acquired by the gamma camera. We observed that the gamma ray energy measured at each step of rotation gradually decreased from the characteristic energy of 140.5keV at 0° to 102.5keV at 120°. A comparison between the obtained data and the expected results from the Compton formula and from the Monte Carlo simulation revealed a full agreement within the experimental error (relative errors between -0.56% and 1.19%), given by the energy resolution of the gamma camera. Also the electron rest mass has been evaluated satisfactorily. The experiment was found useful in explaining nuclear medicine residents the phenomenology of the Compton scattering and its importance in the nuclear medicine imaging, and it can be profitably proposed during the training of medical physics residents as well. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

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

International Nuclear Information System (INIS)

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

2008-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2008-09-01

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

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

Science.gov (United States)

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

2008-09-01

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

Laser Compton polarimetry of proton beams

International Nuclear Information System (INIS)

Stillman, A.

1995-01-01

A need exists for non-destructive polarization measurements of the polarized proton beams in the AGS and, in the future, in RHIC. One way to make such measurements is to scatter photons from the polarized beams. Until now, such measurements were impossible because of the extremely low Compton scattering cross section from protons. Modern lasers now can provide enough photons per laser pulse not only to scatter from proton beams but also, at least in RHIC, to analyze their polarization

Detection of detachments and inhomogeneities in frescos by Compton scattering

Energy Technology Data Exchange (ETDEWEB)

Castellano, A. [Dipartimento di Scienza dei Materiali, Universita di Lecce, 73100 Lecce (Italy); INFN, Sezione di Lecce, via per Arnesano, 73100 Lecce (Italy); Cesareo, R. [Istituto di Matematica e Fisica, Universita di Sassari, 07100 Sassari (Italy) and INFN, Sezione di Cagliari, Cittadella Universitaria di Monserrato, 09042 Cagliari (Italy)]. E-mail: cesareo@uniss.it; Buccolieri, G. [Dipartimento di Scienza dei Materiali, Universita di Lecce, 73100 Lecce (Italy); INFN, Sezione di Lecce, via per Arnesano, 73100 Lecce (Italy); Donativi, M. [Dipartimento di Scienza dei Materiali, Universita di Lecce, 73100 Lecce (Italy); Palama, F. [Dipartimento di Scienza dei Materiali, Universita di Lecce, 73100 Lecce (Italy); INFN, Sezione di Lecce, via per Arnesano, 73100 Lecce (Italy); Quarta, S. [Dipartimento di Scienza dei Materiali, Universita di Lecce, 73100 Lecce (Italy); INFN, Sezione di Lecce, via per Arnesano, 73100 Lecce (Italy); De Nunzio, G. [Dipartimento di Scienza dei Materiali, Universita di Lecce, 73100 Lecce (Italy); INFN, Sezione di Lecce, via per Arnesano, 73100 Lecce (Italy); Brunetti, A. [Istituto di Matematica e Fisica, Universita di Sassari, 07100 Sassari (Italy); INFN, Sezione di Cagliari, Cittadella Universitaria di Monserrato, 09042 Cagliari (Italy); Marabelli, M. [Istituto Centrale del Restauro, P.zza S. Francesco di Paola, 00184 Rome (Italy); Santamaria, U. [Laboratori dei Musei Vaticani, Citta del Vaticano, Rome (Italy)

2005-07-01

A mobile instrument has been developed for the detection and mapping of detachments in frescos by using Compton back scattered photons. The instrument is mainly composed of a high energy X-ray tube, an X-ray detection system and a translation table. The instrument was first applied to samples simulating various detachment situations, and then transferred to the Vatican Museum to detect detachments and inhomogeneities in the stanza di Eliodoro, one of the 'Raphael's stanze'.

Measurement of the Proton Structure Function $F_{2}$ at low $Q^{2}$ in QED Compton Scattering at HERA

CERN Document Server

Aktas, A.; Anthonis, T.; Asmone, A.; Babaev, A.; Backovic, S.; Bahr, J.; Baranov, P.; Barrelet, E.; Bartel, W.; Baumgartner, S.; Becker, J.; Beckingham, M.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, Ch.; Berger, N.; Berndt, T.; Bizot, J.C.; Bohme, J.; Boenig, M.-O.; Boudry, V.; Bracinik, J.; Brisson, V.; Broker, H.-B.; Brown, D.P.; Bruncko, D.; Busser, F.W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Caron, S.; Cassol-Brunner, F.; Cerny, K.; Chekelian, V.; Collard, C.; Contreras, J.G.; Coppens, Y.R.; Coughlan, J.A.; Cox, B.E.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Dau, W.D.; Daum, K.; Delcourt, B.; Demirchyan, R.; De Roeck, A.; Desch, K.; De Wolf, E.A.; Diaconu, C.; Dingfelder, J.; Dodonov, V.; Dubak, A.; Duprel, C.; Eckerlin, Guenter; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Ellerbrock, M.; Elsen, E.; Erdmann, M.; Erdmann, W.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Ferencei, J.; Fleischer, M.; Fleischmann, P.; Fleming, Y.H.; Flucke, G.; Flugge, G.; Fomenko, A.; Foresti, I.; Formanek, J.; Franke, G.; Frising, G.; Gabathuler, E.; Gabathuler, K.; Garutti, E.; Garvey, J.; Gayler, J.; Gerhards, R.; Gerlich, C.; Ghazaryan, Samvel; Goerlich, L.; Gogitidze, N.; Gorbounov, S.; Grab, C.; Grassler, H.; Greenshaw, T.; Gregori, M.; Grindhammer, Guenter; Gwilliam, C.; Haidt, D.; Hajduk, L.; Haller, J.; Hansson, M.; Heinzelmann, G.; Henderson, R.C.W.; Henschel, H.; Henshaw, O.; Heremans, R.; Herrera, G.; Herynek, I.; Heuer, R.-D.; Hildebrandt, M.; Hiller, K.H.; Hoting, P.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Ibbotson, M.; Ismail, M.; Jacquet, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jung, H.; Kant, D.; Kapichine, M.; Karlsson, M.; Katzy, J.; Keller, N.; Kennedy, J.; Kenyon, I.R.; Kiesling, Christian M.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knies, G.; Knutsson, A.; Koblitz, B.; Korbel, V.; Kostka, P.; Koutouev, R.; Kropivnitskaya, A.; Kroseberg, J.; Kuckens, J.; Kuhr, T.; Landon, M.P.J.; Lange, W.; Lastovicka, T.; Laycock, P.; Lebedev, A.; Leiner, B.; Lemrani, R.; Lendermann, V.; Levonian, S.; Lindfeld, L.; Lipka, K.; List, B.; Lobodzinska, E.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lueders, H.; Luke, D.; Lux, T.; Lytkin, L.; Makankine, A.; Malden, N.; Malinovski, E.; Mangano, S.; Marage, P.; Marks, J.; Marshall, R.; Martisikova, M.; Martyn, H.-U.; Maxfield, S.J.; Meer, D.; Mehta, A.; Meier, K.; Meyer, A.B.; Meyer, H.; Meyer, J.; Michine, S.; Mikocki, S.; Milcewicz-Mika, I.; Milstead, D.; Mohamed, A.; Moreau, F.; Morozov, A.; Morozov, I.; Morris, J.V.; Mozer, Matthias Ulrich; Muller, K.; Murin, P.; Nagovizin, V.; Naroska, B.; Naumann, J.; Naumann, Th.; Newman, Paul R.; Niebuhr, C.; Nikiforov, A.; Nikitin, D.; Nowak, G.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J.E.; Ossoskov, G.; Ozerov, D.; Pascaud, C.; Patel, G.D.; Peez, M.; Perez, E.; Perieanu, A.; Petrukhin, A.; Pitzl, D.; Placakyte, R.; Poschl, R.; Portheault, B.; Povh, B.; Raicevic, N.; Ratiani, Z.; Reimer, P.; Reisert, B.; Rimmer, A.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Rybicki, K.; Sankey, D.P.C.; Sauvan, E.; Schatzel, S.; Scheins, J.; Schilling, F.-P.; Schleper, P.; Schmidt, S.; Schmitt, S.; Schneider, M.; Schoeffel, L.; Schoning, A.; Schroder, V.; Schultz-Coulon, H.-C.; Schwanenberger, C.; Sedlak, K.; Sefkow, F.; Sheviakov, I.; Shtarkov, L.N.; Sirois, Y.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Spitzer, H.; Stamen, R.; Stella, B.; Stiewe, J.; Strauch, I.; Straumann, U.; Tchoulakov, V.; Thompson, Graham; Thompson, P.D.; Tomasz, F.; Traynor, D.; Truoel, Peter; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Uraev, A.; Urban, Marcel; Usik, A.; Utkin, D.; Valkar, S.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Van Remortel, N.; Vargas Trevino, A.; Vazdik, Y.; Veelken, C.; Vest, A.; Vinokurova, S.; Volchinski, V.; Wacker, K.; Wagner, J.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Werner, N.; Wessels, M.; Wessling, B.; Winter, G.-G.; Wissing, Ch.; Woehrling, E.-E.; Wolf, R.; Wunsch, E.; Xella, S.; Yan, W.; Yeganov, V.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zohrabyan, H.; Zomer, F.

2004-01-01

The proton structure function F_2(x,Q^2) is measured in inelastic QED Compton scattering using data collected with the H1 detector at HERA. QED Compton events are used to access the kinematic range of very low virtualities of the exchanged photon, Q^2, down to 0.5 GeV^2, and Bjorken x up to \\sim 0.06, a region which has not been covered previously by inclusive measurements at HERA. The results are in agreement with the measurements from fixed target lepton-nucleon scattering experiments.

Deeply virtual Compton scattering off unpolarised deuterium at HERMES

Energy Technology Data Exchange (ETDEWEB)

Hill, Gordon D.

2008-10-15

The HERMES experiment was a forward angle spectrometer on the HERA storage ring at DESY, Hamburg, Germany. HERMES successfully increased understanding of the ''spin puzzle'', the spin structure of the nucleon, by providing high precision measurements of {delta}{sigma} in the Quark Parton Model, the fraction of the spin carried by the current quarks. Following the link of another piece of the puzzle, the orbital angular momentum of quarks and gluons, to the Generalised Parton Distribution (GPD) theoretical framework, HERMES focused on measurements of the Deeply Virtual Compton Scattering (DVCS) process. These measurements are sensitive to GPDs, allowing further experimental constraints to be made on the components of nucleon spin. In the Winter shutdown period 2005-2006 HERMES was upgraded with a Recoil Detector in the target region. This allowed the experiment to make exclusive measurements of the DVCS process for the rst time, reducing background and increasing the resolution of various kinematic variables. The method for reconstructing particle tracks in the inhomogeneous magnetic eld is investigated here. DVCS o a deuterium target is measured with all available data prior to the installation of the Recoil Detector. A comparison is made to currently available models of spin-(1)/(2) GPDs. This analysis has been approved for publication by the HERMES collaboration. The data is further employed in an investigation of a model dependent constraint of the total angular momentum of up and down quarks in the nucleon. (orig.)

Deeply virtual Compton scattering off unpolarised deuterium at HERMES

International Nuclear Information System (INIS)

Hill, Gordon D.

2008-08-01

The HERMES experiment was a forward angle spectrometer on the HERA storage ring at DESY, Hamburg, Germany. HERMES successfully increased understanding of the ''spin puzzle'', the spin structure of the nucleon, by providing high precision measurements of ΔΣ in the Quark Parton Model, the fraction of the spin carried by the current quarks. Following the link of another piece of the puzzle, the orbital angular momentum of quarks and gluons, to the Generalised Parton Distribution (GPD) theoretical framework, HERMES focused on measurements of the Deeply Virtual Compton Scattering (DVCS) process. These measurements are sensitive to GPDs, allowing further experimental constraints to be made on the components of nucleon spin. In the Winter shutdown period 2005-2006 HERMES was upgraded with a Recoil Detector in the target region. This allowed the experiment to make exclusive measurements of the DVCS process for the rst time, reducing background and increasing the resolution of various kinematic variables. The method for reconstructing particle tracks in the inhomogeneous magnetic eld is investigated here. DVCS o a deuterium target is measured with all available data prior to the installation of the Recoil Detector. A comparison is made to currently available models of spin-(1)/(2) GPDs. This analysis has been approved for publication by the HERMES collaboration. The data is further employed in an investigation of a model dependent constraint of the total angular momentum of up and down quarks in the nucleon. (orig.)

Deeply virtual Compton scattering off unpolarised deuterium at HERMES

Energy Technology Data Exchange (ETDEWEB)

Hill, Gordon D

2008-10-15

The HERMES experiment was a forward angle spectrometer on the HERA storage ring at DESY, Hamburg, Germany. HERMES successfully increased understanding of the ''spin puzzle'', the spin structure of the nucleon, by providing high precision measurements of {delta}{sigma} in the Quark Parton Model, the fraction of the spin carried by the current quarks. Following the link of another piece of the puzzle, the orbital angular momentum of quarks and gluons, to the Generalised Parton Distribution (GPD) theoretical framework, HERMES focused on measurements of the Deeply Virtual Compton Scattering (DVCS) process. These measurements are sensitive to GPDs, allowing further experimental constraints to be made on the components of nucleon spin. In the Winter shutdown period 2005-2006 HERMES was upgraded with a Recoil Detector in the target region. This allowed the experiment to make exclusive measurements of the DVCS process for the rst time, reducing background and increasing the resolution of various kinematic variables. The method for reconstructing particle tracks in the inhomogeneous magnetic eld is investigated here. DVCS o a deuterium target is measured with all available data prior to the installation of the Recoil Detector. A comparison is made to currently available models of spin-(1)/(2) GPDs. This analysis has been approved for publication by the HERMES collaboration. The data is further employed in an investigation of a model dependent constraint of the total angular momentum of up and down quarks in the nucleon. (orig.)

Forward scattering effects on muon imaging

Science.gov (United States)

Gómez, H.; Gibert, D.; Goy, C.; Jourde, K.; Karyotakis, Y.; Katsanevas, S.; Marteau, J.; Rosas-Carbajal, M.; Tonazzo, A.

2017-12-01

Muon imaging is one of the most promising non-invasive techniques for density structure scanning, specially for large objects reaching the kilometre scale. It has already interesting applications in different fields like geophysics or nuclear safety and has been proposed for some others like engineering or archaeology. One of the approaches of this technique is based on the well-known radiography principle, by reconstructing the incident direction of the detected muons after crossing the studied objects. In this case, muons detected after a previous forward scattering on the object surface represent an irreducible background noise, leading to a bias on the measurement and consequently on the reconstruction of the object mean density. Therefore, a prior characterization of this effect represents valuable information to conveniently correct the obtained results. Although the muon scattering process has been already theoretically described, a general study of this process has been carried out based on Monte Carlo simulations, resulting in a versatile tool to evaluate this effect for different object geometries and compositions. As an example, these simulations have been used to evaluate the impact of forward scattered muons on two different applications of muon imaging: archaeology and volcanology, revealing a significant impact on the latter case. The general way in which all the tools used have been developed can allow to make equivalent studies in the future for other muon imaging applications following the same procedure.

Compton scattering spectrum as a source of information of normal and neoplastic breast tissues' composition

Energy Technology Data Exchange (ETDEWEB)

Antoniassi, M.; Conceicao, A.L.C. [Departamento de Fisica-Faculdade de Filosofia Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, Ribeirao Preto, 14040-901 Sao Paulo (Brazil); Poletti, M.E., E-mail: poletti@ffclrp.usp.br [Departamento de Fisica-Faculdade de Filosofia Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, Ribeirao Preto, 14040-901 Sao Paulo (Brazil)

2012-07-15

In this work we measured X-ray scatter spectra from normal and neoplastic breast tissues using photon energy of 17.44 keV and a scattering angle of 90 Degree-Sign , in order to study the shape (FWHM) of the Compton peaks. The obtained results for FWHM were discussed in terms of composition and histological characteristics of each tissue type. The statistical analysis shows that the distribution of FWHM of normal adipose breast tissue clearly differs from all other investigated tissues. Comparison between experimental values of FWHM and effective atomic number revealed a strong correlation between them, showing that the FWHM values can be used to provide information about elemental composition of the tissues. - Highlights: Black-Right-Pointing-Pointer X-ray scatter spectra from normal and neoplastic breast tissues were measured. Black-Right-Pointing-Pointer Shape (FWHM) of Compton peak was related with elemental composition and characteristics of each tissue type. Black-Right-Pointing-Pointer A statistical hypothesis test showed clear differences between normal and neoplastic breast tissues. Black-Right-Pointing-Pointer There is a strong correlation between experimental values of FWHM and effective atomic number. Black-Right-Pointing-Pointer Shape (FWHM) of Compton peak can be used to provide information about elemental composition of the tissues.

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)

First Exclusive Measurement of Deeply Virtual Compton Scattering off {}^4\mathrm{He} : Toward the 3D Tomography of Nuclei

Energy Technology Data Exchange (ETDEWEB)

Hattawy, M.; Baltzell, N. A.; Dupré, R.; Hafidi, K.; Stepanyan, S.; Bültmann, S.; De Vita, R.; El Alaoui, A.; El Fassi, L.; Egiyan, H.; Girod, F. X.; Guidal, M.; Jenkins, D.; Liuti, S.; Perrin, Y.; Torayev, B.; Voutier, E.; Adhikari, K. P.; Adhikari, S.; Adikaram, D.; Akbar, Z.; Amaryan, M. J.; Anefalos Pereira, S.; Armstrong, Whitney R.; Avakian, H.; Ball, J.; Bashkanov, M.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Biselli, A. S.; Boiarinov, S.; Briscoe, W. J.; Brooks, W. K.; Burkert, V. D.; Thanh Cao, Frank; Carman, D. S.; Celentano, A.; Charles, G.; Chetry, T.; Ciullo, G.; Clark, L.; Colaneri, L.; Cole, P. L.; Contalbrigo, M.; Cortes, O.; Crede, V.; D’Angelo, A.; Dashyan, N.; De Sanctis, E.; Deur, A.; Djalali, C.; Elouadrhiri, L.; Eugenio, P.; Fedotov, G.; Fegan, S.; Fersch, R.; Filippi, A.; Fleming, J. A.; Forest, T. A.; Fradi, A.; Garçon, M.; Gevorgyan, N.; Ghandilyan, Y.; Gilfoyle, G. P.; Giovanetti, K. L.; Gleason, C.; Gohn, W.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guo, L.; Hakobyan, H.; Hanretty, C.; Harrison, N.; Heddle, D.; Hicks, K.; Holtrop, M.; Hughes, S. M.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jiang, H.; Joo, K.; Joosten, S.; Keller, D.; Khachatryan, G.; Khachatryan, M.; Khandaker, M.; Kim, A.; Kim, W.; Klein, A.; Klein, F. J.; Kubarovsky, V.; Kuhn, S. E.; Kuleshov, S. V.; Lanza, L.; Lenisa, P.; Livingston, K.; Lu, H. Y.; MacGregor, I. J. D.; Markov, N.; Mayer, M.; McCracken, M. E.; McKinnon, B.; Meyer, C. A.; Meziani, Z. E.; Mineeva, T.; Mirazita, M.; Mokeev, V.; Montgomery, R. A.; Moutarde, H.; Movsisyan, A.; Munoz Camacho, C.; Nadel-Turonski, P.; Net, L. A.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Osipenko, M.; Ostrovidov, A. I.; Paolone, M.; Paremuzyan, R.; Park, K.; Pasyuk, E.; Phelps, E.; Phelps, W.; Pisano, S.; Pogorelko, O.; Price, J. W.; Prok, Y.; Protopopescu, D.; Ripani, M.; Ritchie, B. G.; Rizzo, A.; Rosner, G.; Rossi, P.; Sabatié, F.; Salgado, C.; Schumacher, R. A.; Seder, E.; Sharabian, Y. G.; Simonyan, A.; Skorodumina, Iu.; Smith, G. D.; Sokhan, D.; Sparveris, N.; Strauch, S.; Taiuti, M.; Ungaro, M.; Voskanyan, H.; Walford, N. K.; Watts, D. P.; Wei, X.; Weinstein, L. B.; Wood, M. H.; Zachariou, N.; Zana, L.; Zhang, J.; Zhao, Z. W.

2017-11-01

We report on the first measurement of the beam-spin asymmetry in the exclusive process of coherent deeply virtual Compton scattering off a nucleus. The experiment uses the 6 GeV electron beam from the Continuous Electron Beam Accelerator Facility (CEBAF) accelerator at Jefferson Lab incident on a pressurized He-4 gaseous target placed in front of the CEBAF Large Acceptance Spectrometer (CLAS). The scattered electron is detected by CLAS and the photon by a dedicated electromagnetic calorimeter at forward angles. To ensure the exclusivity of the process, a specially designed radial time projection chamber is used to detect the recoiling He-4 nuclei. We measure beam-spin asymmetries larger than those observed on the free proton in the same kinematic domain. From these, we are able to extract, in a model-independent way, the real and imaginary parts of the only He-4 Compton form factor, HA. This first measurement of coherent deeply virtual Compton scattering on the He-4 nucleus, with a fully exclusive final state via nuclear recoil tagging, leads the way toward 3D imaging of the partonic structure of nuclei.

Compton scattering artifacts in electron excited X-ray spectra measured with a silicon drift detector.

Science.gov (United States)

Ritchie, Nicholas W M; Newbury, Dale E; Lindstrom, Abigail P

2011-12-01

Artifacts are the nemesis of trace element analysis in electron-excited energy dispersive X-ray spectrometry. Peaks that result from nonideal behavior in the detector or sample can fool even an experienced microanalyst into believing that they have trace amounts of an element that is not present. Many artifacts, such as the Si escape peak, absorption edges, and coincidence peaks, can be traced to the detector. Others, such as secondary fluorescence peaks and scatter peaks, can be traced to the sample. We have identified a new sample-dependent artifact that we attribute to Compton scattering of energetic X-rays generated in a small feature and subsequently scattered from a low atomic number matrix. It seems likely that this artifact has not previously been reported because it only occurs under specific conditions and represents a relatively small signal. However, with the advent of silicon drift detectors and their utility for trace element analysis, we anticipate that more people will observe it and possibly misidentify it. Though small, the artifact is not inconsequential. Under some conditions, it is possible to mistakenly identify the Compton scatter artifact as approximately 1% of an element that is not present.

Deeply virtual Compton scattering from gauge/gravity duality

Energy Technology Data Exchange (ETDEWEB)

Costa, Miguel S.; Djuric, Marko [University of Porto (Portugal)

2013-04-15

We use gauge/gravity duality to study deeply virtual Compton scattering (DVCS) in the limit of high center of mass energy at fixed momentum transfer, corresponding to the limit of low Bjorken x, where the process is dominated by the exchange of the pomeron. At strong coupling, the pomeron is described as the graviton Regge trajectory in AdS space, with a hard wall to mimic confinement effects. This model agrees with HERA data in a large kinematical range. The behavior of the DVCS cross section for very high energies, inside saturation, can be explained by a simple AdS black disk model. In a restricted kinematical window, this model agrees with HERA data as well.

Deeply virtual Compton scattering from gauge/gravity duality

International Nuclear Information System (INIS)

Costa, Miguel S.; Djurić, Marko

2013-01-01

We use gauge/gravity duality to study deeply virtual Compton scattering (DVCS) in the limit of high center of mass energy at fixed momentum transfer, corresponding to the limit of low Bjorken x, where the process is dominated by the exchange of the pomeron. At strong coupling, the pomeron is described as the graviton Regge trajectory in AdS space, with a hard wall to mimic confinement effects. This model agrees with HERA data in a large kinematical range. The behavior of the DVCS cross section for very high energies, inside saturation, can be explained by a simple AdS black disk model. In a restricted kinematical window, this model agrees with HERA data as well.

Sound extinction by fish schools: forward scattering theory and data analysis.

Science.gov (United States)

Raveau, M; Feuillade, C

2015-02-01

A model used previously to study collective back scattering from fish schools [Feuillade et al., J. Acoust. Soc. Am. 99(1), 196-208 (1996)], is used to analyze the forward scattering properties of these objects. There is an essential physical difference between back and forward scattering from fish schools. Strong frequency dependent interference effects, which affect the back scattered field amplitude, are absent in the forward scattering case. This is critically important for data analysis. There is interest in using back scattering and transmission data from fish schools to study their size, the species and abundance of fish, and fish behavior. Transmission data can be processed to determine the extinction of the field by a school. The extinction of sound depends on the forward scattering characteristics of the school, and data inversion to provide information about the fish should be based upon a forward scattering paradigm. Results are presented of an analysis of transmission data obtained in September 1995 during an experiment performed in the Gulf of Lion in the Mediterranean Sea [Diachok, J. Acoust. Soc. Am. 105(4), 2107-2128 (1999)]. The analysis shows that using forward scattering leads to significantly larger estimates of fish abundance than previous analysis based upon back scattering approaches.

Compton scatter imaging: A promising modality for image guidance in lung stereotactic body radiation therapy.

Science.gov (United States)

Redler, Gage; Jones, Kevin C; Templeton, Alistair; Bernard, Damian; Turian, Julius; Chu, James C H

2018-03-01

Lung stereotactic body radiation therapy (SBRT) requires delivering large radiation doses with millimeter accuracy, making image guidance essential. An approach to forming images of patient anatomy from Compton-scattered photons during lung SBRT is presented. To investigate the potential of scatter imaging, a pinhole collimator and flat-panel detector are used for spatial localization and detection of photons scattered during external beam therapy using lung SBRT treatment conditions (6 MV FFF beam). MCNP Monte Carlo software is used to develop a model to simulate scatter images. This model is validated by comparing experimental and simulated phantom images. Patient scatter images are then simulated from 4DCT data. Experimental lung tumor phantom images have sufficient contrast-to-noise to visualize the tumor with as few as 10 MU (0.5 s temporal resolution). The relative signal intensity from objects of different composition as well as lung tumor contrast for simulated phantom images agree quantitatively with experimental images, thus validating the Monte Carlo model. Scatter images are shown to display high contrast between different materials (lung, water, bone). Simulated patient images show superior (~double) tumor contrast compared to MV transmission images. Compton scatter imaging is a promising modality for directly imaging patient anatomy during treatment without additional radiation, and it has the potential to complement existing technologies and aid tumor tracking and lung SBRT image guidance. © 2018 American Association of Physicists in Medicine.

First measurement of $Z/\\gamma^{*}$ production in Compton scattering of quasi-real photons

CERN Document Server

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.

A successful experimental observation of double-photon Compton scattering of γ rays using a single γ detector

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

Corrections for the effects of accidental coincidences, Compton scatter, and object size in positron emission mammography (PEM) imaging

Science.gov (United States)

Raylman, R. R.; Majewski, S.; Wojcik, R.; Weisenberger, A. G.; Kross, B.; Popov, V.

2001-06-01

Positron emission mammography (PEM) has begun to show promise as an effective method for the detection of breast lesions. Due to its utilization of tumor-avid radiopharmaceuticals labeled with positron-emitting radionuclides, this technique may be especially useful in imaging of women with radiodense or fibrocystic breasts. While the use of these radiotracers affords PEM unique capabilities, it also introduces some limitations. Specifically, acceptance of accidental and Compton-scattered coincidence events can decrease lesion detectability. The authors studied the effect of accidental coincidence events on PEM images produced by the presence of /sup 18/F-Fluorodeoxyglucose in the organs of a subject using an anthropomorphic phantom. A delayed-coincidence technique was tested as a method for correcting PEM images for the occurrence of accidental events. Also, a Compton scatter correction algorithm designed specifically for PEM was developed and tested using a compressed breast phantom. Finally, the effect of object size on image counts and a correction for this effect were explored. The imager used in this study consisted of two PEM detector heads mounted 20 cm apart on a Lorad biopsy apparatus. The results demonstrated that a majority of the accidental coincidence events (/spl sim/80%) detected by this system were produced by radiotracer uptake in the adipose and muscle tissue of the torso. The presence of accidental coincidence events was shown to reduce lesion detectability. Much of this effect was eliminated by correction of the images utilizing estimates of accidental-coincidence contamination acquired with delayed coincidence circuitry built into the PEM system. The Compton scatter fraction for this system was /spl sim/14%. Utilization of a new scatter correction algorithm reduced the scatter fraction to /spl sim/1.5%. Finally, reduction of count recovery due to object size was measured and a correction to the data applied. Application of correction techniques

Evaluation of Position Resolution for a Prototype Whole-Body PET Detector Based on Suppressing Backgrounds by Compton Scattering

Science.gov (United States)

Fujihara, Kento; Emoto, Yusaku; Ito, Hiroshi; Kaneko, Naomi; Kaneko, Hideyuki; Kawai, Hideyuki; Kobayashi, Atsushi; Mizuno, Takahiro

2018-01-01

Existing PET (Positron Emission Tomography) systems make clear images in demonstration (measuring small PET reagent in pure water), however images in real diagnosis become unclear. The authors suspected that this problem was caused by Compton scattering in a detector. When PET systems observe plural photomultiplier tube outputs, an original emission point is regarded as centroid of the outputs. However, even if plural emission in Compton scattering occur, these systems calculate original point in the same way as single emission. Therefore, the authors considered that rejecting Compton scattering events makes PET systems much better, and made prototype counter. Main components of the prototype counter are plate-like high-growth-rate (HGR) La-GPS scintillators and wavelength shifting fibers (WLSF). HGR crystals grow 10 times as fast as a mono-crystal (a normal mono-crystal grows at 2 - 3 mm an hour). Thus, it includes microbubble and its transparency get worth. Consequently, HGR crystals usually are not used in radiation measuring instruments. However, this time they are used on the purpose. Because of their low transparency, scintillation lights come out right above and right under of emission position. Therefore, Compton scattering events is rejected easily. The prototype detector has an effective area of 300 by 300 square mm. The detector consists of 24 layers. One layer consists of HGR La-GPS scintillator of 1 mm thickness. Top and bottom surface of scintillator were covered by dual sheets of WLSF with a diameter of 0.2 mm. Sheets of WLSF on top and bottom of the scintillator make a right angle with each other, and measure X- and Y-components. Z-component is measured by difference of WLSF outputs between top and bottom. If plural layers output signals, this counter regards the event as Compton scattering event, and reject the event. Even if only a layer output signals, the event is rejected when number output signals from WLSF is more than 1.5 times of single

A glimpse of gluons through deeply virtual compton scattering on the proton.

Science.gov (United States)

Defurne, M; Jiménez-Argüello, A Martí; Ahmed, Z; Albataineh, H; Allada, K; Aniol, K A; Bellini, V; Benali, M; Boeglin, W; Bertin, P; Brossard, M; Camsonne, A; Canan, M; Chandavar, S; Chen, C; Chen, J-P; de Jager, C W; de Leo, R; Desnault, C; Deur, A; El Fassi, L; Ent, R; Flay, D; Friend, M; Fuchey, E; Frullani, S; Garibaldi, F; Gaskell, D; Giusa, A; Glamazdin, O; Golge, S; Gomez, J; Hansen, O; Higinbotham, D; Holmstrom, T; Horn, T; Huang, J; Huang, M; Hyde, C E; Iqbal, S; Itard, F; Kang, H; Kelleher, A; Keppel, C; Koirala, S; Korover, I; LeRose, J J; Lindgren, R; Long, E; Magne, M; Mammei, J; Margaziotis, D J; Markowitz, P; Mazouz, M; Meddi, F; Meekins, D; Michaels, R; Mihovilovic, M; Camacho, C Muñoz; Nadel-Turonski, P; Nuruzzaman, N; Paremuzyan, R; Puckett, A; Punjabi, V; Qiang, Y; Rakhman, A; Rashad, M N H; Riordan, S; Roche, J; Russo, G; Sabatié, F; Saenboonruang, K; Saha, A; Sawatzky, B; Selvy, L; Shahinyan, A; Sirca, S; Solvignon, P; Sperduto, M L; Subedi, R; Sulkosky, V; Sutera, C; Tobias, W A; Urciuoli, G M; Wang, D; Wojtsekhowski, B; Yao, H; Ye, Z; Zhan, X; Zhang, J; Zhao, B; Zhao, Z; Zheng, X; Zhu, P

2017-11-10

The internal structure of nucleons (protons and neutrons) remains one of the greatest outstanding problems in modern nuclear physics. By scattering high-energy electrons off a proton we are able to resolve its fundamental constituents and probe their momenta and positions. Here we investigate the dynamics of quarks and gluons inside nucleons using deeply virtual Compton scattering (DVCS)-a highly virtual photon scatters off the proton, which subsequently radiates a photon. DVCS interferes with the Bethe-Heitler (BH) process, where the photon is emitted by the electron rather than the proton. We report herein the full determination of the BH-DVCS interference by exploiting the distinct energy dependences of the DVCS and BH amplitudes. In the regime where the scattering is expected to occur off a single quark, measurements show an intriguing sensitivity to gluons, the carriers of the strong interaction.

Verification of Compton scattering spectrum of a 662 keV photon beam scattered on a cylindrical steel target using MCNP5 code

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°.

Directional Stand-off Detection of Fast Neutrons and Gammas Using Angular Scattering Distributions

Energy Technology Data Exchange (ETDEWEB)

Vanier P. e.; Dioszegi, I.; Salwen, C.; Forman, L.

2009-10-25

We have investigated the response of a DoubleScatter Neutron Spectrometer (DSNS) for sources at long distances (gr than 200 meters). We find that an alternative method for analyzing double scatter data avoids some uncertainties introduced by amplitude measurements in plastic scintillators.Time of flight is used to discriminate between gamma and neutron events, and the kinematic distributions of scattering angles are assumed to apply. Non-relativistic neutrons are most likely to scatter at 45°, while gammas with energies greater than 2 MeV are most likely to be forward scattered. The distribution of scattering angles of fission neutrons arriving from a distant point source generates a 45° cone, which can be back-projected to give the source direction. At the same time, the distribution of Compton-scattered gammas has a maximum in the forward direction, and can be made narrower by selecting events that deposit minimal energy in the first scattering event. We have further determined that the shape of spontaneous fission neutron spectra at ranges gr than 110 m is still significantly different from thecosmic ray background.

Charge dependence of the ratio of double to total ionization of a helium-like ion by Compton scattering of a high energy photon

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.)

Experimental test of Bell`s inequalities using angular correlation of compton-scattered annihilation photons

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.

Measurement of Deeply Virtual Compton Scattering at HERA

CERN Document Server

Aktas, A.; Anthonis, T.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Babaev, A.; Backovic, S.; Bahr, J.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Baumgartner, S.; Becker, J.; Beckingham, M.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, Ch.; Berger, N.; Bizot, J.C.; Boenig, M.-O.; Boudry, V.; Bracinik, J.; Brandt, G.; Brisson, V.; Brown, D.P.; Bruncko, D.; Busser, F.W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Caron, S.; Cassol-Brunner, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Contreras, J.G.; Coughlan, J.A.; Cox, B.E.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Dau, W.D.; Daum, K.; de Boer, Y.; Delcourt, B.; Demirchyan, R.; De Roeck, A.; Desch, K.; De Wolf, E.A.; Diaconu, C.; Dodonov, V.; Dubak, A.; Eckerlin, Guenter; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Ellerbrock, M.; Elsen, E.; Erdmann, W.; Essenov, S.; Falkewicz, A.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Ferencei, J.; Finke, L.; Fleischer, M.; Fleischmann, P.; Fleming, Y.H.; Flucke, G.; Fomenko, A.; Foresti, I.; Franke, G.; Frisson, T.; Gabathuler, E.; Garutti, E.; Gayler, J.; Gerlich, C.; Ghazaryan, Samvel; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Goyon, C.; Grab, C.; Greenshaw, T.; Gregori, M.; Grell, B.R.; Grindhammer, Guenter; Gwilliam, C.; Haidt, D.; Hajduk, L.; Haller, J.; Hansson, M.; Heinzelmann, G.; Henderson, R.C.W.; Henschel, H.; Henshaw, O.; Herrera, G.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Ibbotson, M.; Ismail, M.; Jacquet, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jung, H.; Kapichine, M.; Katzy, J.; Keller, N.; Kenyon, I.R.; Kiesling, Christian M.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knies, G.; Knutsson, A.; Korbel, V.; Kostka, P.; Koutouev, R.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Kruger, K.; Kuckens, J.; Landon, M.P.J.; Lange, W.; Lastovicka, T.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Leiner, B.; Lendermann, V.; Levonian, S.; Lindfeld, L.; Lipka, K.; List, B.; Lobodzinska, E.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lueders, H.; Luke, D.; Lux, T.; Lytkin, L.; Makankine, A.; Malden, N.; Malinovski, E.; Mangano, S.; Marage, P.; Marshall, R.; Martisikova, M.; Martyn, H.-U.; Maxeld, S.J.; Meer, D.; Mehta, A.; Meier, K.; Meyer, A.B.; Meyer, H.; Meyer, J.; Mikocki, S.; Milcewicz-Mika, I.; Milstead, D.; Mladenov, D.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J.V.; Mozer, Matthias Ulrich; Muller, K.; Murin, P.; Nankov, K.; Naroska, B.; Naumann, Th.; Newman, Paul R.; Niebuhr, C.; Nikiforov, A.; Nikitin, D.; Nowak, G.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J.E.; Osman, S.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Papadopoulou, T.; Pascaud, C.; Patel, G.D.; Peez, M.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Pitzl, D.; Placakyte, R.; Portheault, B.; Povh, B.; Prideaux, P.; Raicevic, N.; Reimer, P.; Rimmer, A.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Salvaire, F.; Sankey, D.P.C.; Sauvan, E.; Schatzel, S.; Schilling, F.-P.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schoning, A.; Schroder, V.; Schultz-Coulon, H.-C.; Sedlak, K.; Sefkow, F.; Sheviakov, I.; Shtarkov, L.N.; Sirois, Y.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Stella, B.; Stiewe, J.; Strauch, I.; Straumann, U.; Tchoulakov, V.; Thompson, Graham; Thompson, P.D.; Tomasz, F.; Traynor, D.; Truoel, Peter; Tsakov, I.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, Marcel; Usik, A.; Utkin, D.; Valkar, S.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Van Remortel, N.; Vargas Trevino, A.; Vazdik, Y.; Veelken, C.; Vest, A.; Vinokurova, S.; Volchinski, V.; Vujicic, B.; Wacker, K.; Wagner, J.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Werner, N.; Wessels, M.; Wessling, B.; Wigmore, C.; Wissing, Ch.; Wolf, R.; Wunsch, E.; Xella, S.; Yan, W.; Yeganov, V.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zimmermann, J.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.

2005-01-01

A measurement is presented of elastic deeply virtual Compton scattering \\gamma* p \\to \\gamma p made using e^+ p collision data corresponding to a luminosity of 46.5 pb^{-1}, taken with the H1 detector at HERA. The cross section is measured as a function of the photon virtuality, Q^2, the invariant mass of the \\gamma* p system, W, and for the first time, differentially in the squared momentum transfer at the proton vertex, t, in the kinematic range 2 < Q^2 < 80 GeV^2, 30 < W < 140 GeV and |t| < 1 GeV^2. QCD based calculations at next-to-leading order using generalized parton distributions can describe the data, as can colour dipole model predictions.

Stability analysis and time-step limits for a Monte Carlo Compton-scattering method

International Nuclear Information System (INIS)

Densmore, Jeffery D.; Warsa, James S.; Lowrie, Robert B.

2010-01-01

A Monte Carlo method for simulating Compton scattering in high energy density applications has been presented that models the photon-electron collision kinematics exactly [E. Canfield, W.M. Howard, E.P. Liang, Inverse Comptonization by one-dimensional relativistic electrons, Astrophys. J. 323 (1987) 565]. However, implementing this technique typically requires an explicit evaluation of the material temperature, which can lead to unstable and oscillatory solutions. In this paper, we perform a stability analysis of this Monte Carlo method and develop two time-step limits that avoid undesirable behavior. The first time-step limit prevents instabilities, while the second, more restrictive time-step limit avoids both instabilities and nonphysical oscillations. With a set of numerical examples, we demonstrate the efficacy of these time-step limits.

The description of compton lines in energy-dispersive x-ray Fluorescence

International Nuclear Information System (INIS)

Van Gysel, Mon; Van Espen, P.J.M.

2001-01-01

Energy-Dispersive X-Ray Fluorescence (ED-XRF) is a non-destructive technique for the element analysis in a concentration range ppm - % making use of X rays up to 100 keV. Generally, two photon matter interactions occur, respectively absorption and scattering. The absorption of incident photons gives raise to characteristic lines. Scattering gives an incoherent and a coherent line. A Gaussian peak model is adequate to describe the characteristic and coherent scattered lines. Incoherent lines appear as non-Gaussian, broadened peaks. The profile of a Compton peak is complex. It depends on the geometry and the composition of the sample. Especially, when analyzing a low Z matrix; dominant scattering and multiple scattering may cause large interferences. The absence of an appropriate fitting model makes the Compton profile seen as a limiting factor in the evaluation of spectra. An accurate description of incoherent lines should improve quantitative analysis. Therefore, a suitable fitting model, making use of the expertise of non-linear least squares procedures and Monte-Carlo calculations was systematically investigated. The proposed model, containing a modified Gaussian, is tested on experimental data recorded with a HPGe detector

Positron annihilation radiation from the Galactic center - Cheshire cat' Compton scattering and the origin of excess continuum

International Nuclear Information System (INIS)

Bildsten, L.; Zurek, W.H.

1988-01-01

Two observations of the gamma-ray spectrum from the direction of the Galactic center were made by HEAO 3 in the fall of 1979 and the spring of 1980. The 2-gamma 511 keV annihilation line flux decreased by a factor of about three during the 6 months between these observations, while the excess gamma-ray continuum below the annihilation line, often interpreted as 3-gamma decay of orthopositronium, barely changed. This discrepancy in temporal behavior makes the identification of the bulk of excess continuum as 3-gamma decay of positronium difficult. It is shown that Compton scattering of the line and high-energy radiation provides a natural explanation for the surprisingly small changes seen in the excess continuum. Scattered photons are delayed by a time corresponding to the size of the scattering region. For the annihilation source in the Galactic center, this distance is probably a fraction of a parsec. Thus, even after the high-energy continuum and annihilation line are gone, low-energy Compton-scattered photons can still be detected with an almost unchanged flux. 23 references

Ocular forward light scattering and corneal backward light scattering in patients with dry eye.

Science.gov (United States)

Koh, Shizuka; Maeda, Naoyuki; Ikeda, Chikako; Asonuma, Sanae; Mitamura, Hayato; Oie, Yoshinori; Soma, Takeshi; Tsujikawa, Motokazu; Kawasaki, Satoshi; Nishida, Kohji

2014-09-18

To evaluate ocular forward light scattering and corneal backward light scattering in patients with dry eye. Thirty-five eyes in 35 patients with dry eye and 20 eyes of 20 healthy control subjects were enrolled. The 35 dry eyes were classified into two groups according to whether superficial punctate keratopathy in the central 6-mm corneal zone (cSPK) was present or not. Ocular forward light scattering was quantified with a straylight meter. Corneal backward light scattering from the anterior, middle, and posterior corneal parts was assessed with a corneal densitometry program using the Scheimpflug imaging system. Both dry eye groups had significantly higher intraocular forward light scattering than the control group (both Pdry eye group with cSPK had significantly higher values in anterior and total corneal backward light scattering than the other two groups. Moderate positive correlations were observed between the cSPK score and corneal backward light scattering from the anterior cornea (R=0.60, Pdry eyes than in normal eyes. Increased corneal backward light scattering in dry eye at least partially results from cSPK overlying the optical zone. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

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.

Stability analysis of implicit time discretizations for the Compton-scattering Fokker-Planck equation

International Nuclear Information System (INIS)

Densmore, Jeffery D.; Warsa, James S.; Lowrie, Robert B.; Morel, Jim E.

2009-01-01

The Fokker-Planck equation is a widely used approximation for modeling the Compton scattering of photons in high energy density applications. In this paper, we perform a stability analysis of three implicit time discretizations for the Compton-Scattering Fokker-Planck equation. Specifically, we examine (i) a Semi-Implicit (SI) scheme that employs backward-Euler differencing but evaluates temperature-dependent coefficients at their beginning-of-time-step values, (ii) a Fully Implicit (FI) discretization that instead evaluates temperature-dependent coefficients at their end-of-time-step values, and (iii) a Linearized Implicit (LI) scheme, which is developed by linearizing the temperature dependence of the FI discretization within each time step. Our stability analysis shows that the FI and LI schemes are unconditionally stable and cannot generate oscillatory solutions regardless of time-step size, whereas the SI discretization can suffer from instabilities and nonphysical oscillations for sufficiently large time steps. With the results of this analysis, we present time-step limits for the SI scheme that prevent undesirable behavior. We test the validity of our stability analysis and time-step limits with a set of numerical examples.

Stability analysis of implicit time discretizations for the Compton-scattering Fokker-Planck equation

Energy Technology Data Exchange (ETDEWEB)

Densmore, Jeffery D [Los Alamos National Laboratory; Warsa, James S [Los Alamos National Laboratory; Lowrie, Robert B [Los Alamos National Laboratory; Morel, Jim E [TEXAS A& M UNIV

2008-01-01

The Fokker-Planck equation is a widely used approximation for modeling the Compton scattering of photons in high energy density applications. In this paper, we perform a stability analysis of three implicit time discretizations for the Compton-Scattering Fokker-Planck equation. Specifically, we examine (i) a Semi-Implicit (SI) scheme that employs backward-Euler differencing but evaluates temperature-dependent coefficients at their beginning-of-time-step values, (ii) a Fully Implicit (FI) discretization that instead evaluates temperature-dependent coefficients at their end-of-time-step values, and (iii) a Linearized Implicit (LI) scheme, which is developed by linearizing the temperature dependence of the FI discretization within each time step. Our stability analysis shows that the FI and LI schemes are unconditionally stable and cannot generate oscillatory solutions regardless of time-step size, whereas the SI discretization can suffer from instabilities and nonphysical oscillations for sufficiently large time steps. With the results of this analysis, we present time-step limits for the SI scheme that prevent undesirable behavior. We test the validity of our stability analysis and time-step limits with a set of numerical examples.

Stability analysis of implicit time discretizations for the Compton-scattering Fokker-Planck equation

Science.gov (United States)

Densmore, Jeffery D.; Warsa, James S.; Lowrie, Robert B.; Morel, Jim E.

2009-09-01

The Fokker-Planck equation is a widely used approximation for modeling the Compton scattering of photons in high energy density applications. In this paper, we perform a stability analysis of three implicit time discretizations for the Compton-Scattering Fokker-Planck equation. Specifically, we examine (i) a Semi-Implicit (SI) scheme that employs backward-Euler differencing but evaluates temperature-dependent coefficients at their beginning-of-time-step values, (ii) a Fully Implicit (FI) discretization that instead evaluates temperature-dependent coefficients at their end-of-time-step values, and (iii) a Linearized Implicit (LI) scheme, which is developed by linearizing the temperature dependence of the FI discretization within each time step. Our stability analysis shows that the FI and LI schemes are unconditionally stable and cannot generate oscillatory solutions regardless of time-step size, whereas the SI discretization can suffer from instabilities and nonphysical oscillations for sufficiently large time steps. With the results of this analysis, we present time-step limits for the SI scheme that prevent undesirable behavior. We test the validity of our stability analysis and time-step limits with a set of numerical examples.

Source of X-ray radiation based on back compton scattering

CERN Document Server

Bulyak, E V; Karnaukhov, I M; Kononenko, S G; Lapshin, V G; Mytsykov, A O; Telegin, Yu P; Shcherbakov, A A; Zelinsky, Andrey Yurij

2000-01-01

Applicability was studied and previous estimation was done of power X-ray beams generation by backward Compton scattering of a laser photon beam on a cooled down electron beam. The few MeV electron beam circulating in a compact storage ring can be cooled down by interaction of that beam with powerful laser radiation of micrometer wavelength to achieve normalized emittance of 10 sup - sup 7 m. A tunable X-ray source of photons of energy ranging from few keV up to a hundred keV could result from the interaction of the laser beam with a dense electron beam.

Source of X-ray radiation based on back compton scattering

Energy Technology Data Exchange (ETDEWEB)

Bulyak, E.V.; Gladkikh, P.I.; Karnaukhov, I.M.; Kononenko, S.G.; Lapshin, V.I.; Mytsykov, A.O.; Telegin, Yu.N.; Shcherbakov, A.A. E-mail: shcherbakov@kipt.kharkov.ua; Zelinsky, A.Yu

2000-06-21

Applicability was studied and previous estimation was done of power X-ray beams generation by backward Compton scattering of a laser photon beam on a cooled down electron beam. The few MeV electron beam circulating in a compact storage ring can be cooled down by interaction of that beam with powerful laser radiation of micrometer wavelength to achieve normalized emittance of 10{sup -7} m. A tunable X-ray source of photons of energy ranging from few keV up to a hundred keV could result from the interaction of the laser beam with a dense electron beam.

Source of X-ray radiation based on back compton scattering

International Nuclear Information System (INIS)

Bulyak, E.V.; Gladkikh, P.I.; Karnaukhov, I.M.; Kononenko, S.G.; Lapshin, V.I.; Mytsykov, A.O.; Telegin, Yu.N.; Shcherbakov, A.A.; Zelinsky, A.Yu.

2000-01-01

Applicability was studied and previous estimation was done of power X-ray beams generation by backward Compton scattering of a laser photon beam on a cooled down electron beam. The few MeV electron beam circulating in a compact storage ring can be cooled down by interaction of that beam with powerful laser radiation of micrometer wavelength to achieve normalized emittance of 10 -7 m. A tunable X-ray source of photons of energy ranging from few keV up to a hundred keV could result from the interaction of the laser beam with a dense electron beam

SU-E-T-90: Concrete Forward-Scatter Fractions for Radiotherapy Shielding Applications

International Nuclear Information System (INIS)

Tanny, S; Parsai, E

2014-01-01

Purpose: There is little instruction within the primary shielding guidance document NCRP 151 for vault designs where the primary beam intercepts the maze. We have conducted a Monte-Carlo study to characterize forward-scattered radiation from concrete barriers with the intent of quantifying what amount of additional shielding outside the primary beam is needed in this situation. Methods: We reproduced our vault in MCNP 5 and simulated spectra obtained from the literature and from our treatment planning system for 10 and 18 MV beams. Neutron and gamma-capture contributions were not simulated. Energy deposited was scored at isocenter in a water phantom, within various cells that comprised the maze, and within cells that comprised the vault door. Tracks were flagged that scattered from within the maze to the door and their contributions were tallied separately. Three different concrete mixtures found in the literature were simulated. An empirically derived analytic equation was used for comparison, utilizing patient scatter fractions to approximate the scatter from concrete. Results: Our simulated data confirms that maze-scattered radiation is a significant contribution to total photon dose at the door. It contributes between 20-35% of the photon shielding workload. Forward-scatter fractions for concrete were somewhat dependent on concrete composition and the relative abundance of higher-Z elements. Scatter fractions were relatively insensitive to changes in the primary photon spectrum. Analytic results were of the same magnitude as simulated results. Conclusions: Forward-scattered radiation from the maze barrier needs to be included in the photon workload for shielding calculations in non-standard vault designs. Scatter fractions will vary with concrete composition, but should be insensitive to spectral changes between machine manufacturers. Further plans for investigation include refined scatter fractions for various concrete compositions, scatter fraction

SU-E-T-90: Concrete Forward-Scatter Fractions for Radiotherapy Shielding Applications

Energy Technology Data Exchange (ETDEWEB)

Tanny, S; Parsai, E [University of Toledo Medical Center, Toledo, OH (United States)

2014-06-01

Purpose: There is little instruction within the primary shielding guidance document NCRP 151 for vault designs where the primary beam intercepts the maze. We have conducted a Monte-Carlo study to characterize forward-scattered radiation from concrete barriers with the intent of quantifying what amount of additional shielding outside the primary beam is needed in this situation. Methods: We reproduced our vault in MCNP 5 and simulated spectra obtained from the literature and from our treatment planning system for 10 and 18 MV beams. Neutron and gamma-capture contributions were not simulated. Energy deposited was scored at isocenter in a water phantom, within various cells that comprised the maze, and within cells that comprised the vault door. Tracks were flagged that scattered from within the maze to the door and their contributions were tallied separately. Three different concrete mixtures found in the literature were simulated. An empirically derived analytic equation was used for comparison, utilizing patient scatter fractions to approximate the scatter from concrete. Results: Our simulated data confirms that maze-scattered radiation is a significant contribution to total photon dose at the door. It contributes between 20-35% of the photon shielding workload. Forward-scatter fractions for concrete were somewhat dependent on concrete composition and the relative abundance of higher-Z elements. Scatter fractions were relatively insensitive to changes in the primary photon spectrum. Analytic results were of the same magnitude as simulated results. Conclusions: Forward-scattered radiation from the maze barrier needs to be included in the photon workload for shielding calculations in non-standard vault designs. Scatter fractions will vary with concrete composition, but should be insensitive to spectral changes between machine manufacturers. Further plans for investigation include refined scatter fractions for various concrete compositions, scatter fraction

Deeply virtual compton scattering in color dipole formalism

International Nuclear Information System (INIS)

Machado, Magno V.T.

2007-01-01

In this contribution we summarize recent investigations on the Deeply Virtual Compton Scattering (DVCS) within the color dipole approach. The color dipole cross section is implemented through the phenomenological saturation model. The role played by its QCD evolution and skewedness effects in the DVCS cross section are discussed. The results are compared with the recent H1 and ZEUS Collaborations data. The skewing factor, defined as the ratio of the imaginary parts of the amplitudes Im A(γ* p → γ* p)/ Im A(γ* p → γ p) can be extracted from the data using recent DVCS and the inclusive inelastic cross section measurements at DESY-HERA. We report on this experimental extraction and compare the results to the theoretical predictions for NLO QCD and the color dipole approach. (author)

Lorentz violation and black-hole thermodynamics: Compton scattering process

International Nuclear Information System (INIS)

Kant, E.; Klinkhamer, F.R.; Schreck, M.

2009-01-01

A Lorentz-noninvariant modification of quantum electrodynamics (QED) is considered, which has photons described by the nonbirefringent sector of modified Maxwell theory and electrons described by the standard Dirac theory. These photons and electrons are taken to propagate and interact in a Schwarzschild spacetime background. For appropriate Lorentz-violating parameters, the photons have an effective horizon lying outside the Schwarzschild horizon. A particular type of Compton scattering event, taking place between these two horizons (in the photonic ergoregion) and ultimately decreasing the mass of the black hole, is found to have a nonzero probability. These events perhaps allow for a violation of the generalized second law of thermodynamics in the Lorentz-noninvariant theory considered.

Virtual compton scattering on the proton below pion threshold

International Nuclear Information System (INIS)

Bertin, P.Y.

1995-01-01

This paper presents the preliminary results of an electron-proton interaction experiment carried out with the accelerator of MAMI at Mainz (Germany) for the recording of virtual compton scattering events. More than 2 10 4 events were recorded in a two days run with a liquid hydrogen target. The main limitation for the counting rate comes from the limitation of the acquisition rate (100 Hz) and the single rates (10 5 ) in the drift chambers. The aim of this experiment is the understanding of both the low energy expansion and the generalized polarizabilities in order to compare, confirm or exclude the models of Quantum Chromodynamics used for the understanding of the nucleon. (J.S.). 3 refs., 5 figs

Circumstances under which various approximate relativistic and nonrelativistic theories yield accurate Compton scattering doubly differential cross sections at high photon energy

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.

Energy and intensity distributions of 0.279 MeV multiply Compton-scattered photons in soldering material

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

Measurements of Compton Scattering on the Proton at 2 - 6 GeV

Energy Technology Data Exchange (ETDEWEB)

Danagoulian, Areg [Univ. of Illinois, Urbana-Champaign, IL (United States)

2006-01-01

Similar to elastic electron scattering, Compton Scattering on the proton at high momentum transfers(and high p⊥) can be an effective method to study its short-distance structure. An experiment has been carried out to measure the cross sections for Real Compton Scattering (RCS) on the proton for 2.3-5.7 GeV electron beam energies and a wide distribution of large scattering angles. The 25 kinematic settings sampled a domain of s = 5-11(GeV/c)²,-t = -7(GeV/c)² and -u = 0.5-6.5(GeV/c)². In addition, a measurement of longitudinal and transverse polarization transfer asymmetries was made at a 3.48 GeV beam energy and a scattering angle of θ_cm = 120°. These measurements were performed to test the existing theoretical mechanisms for this process as well as to determine RCS form factors. At the heart of the scientific motivation is the desire to understand the manner in which a nucleon interacts with external excitations at the above listed energies, by comparing and contrasting the two existing models – Leading Twist Mechanism and Soft Overlap “Handbag” Mechanism – and identify the dominant mechanism. Furthermore, the Handbag Mechanism allows one to calculate reaction observables in the framework of Generalized Parton Distributions (GPD), which have the function of bridging the wide gap between the exclusive(form factors) and inclusive(parton distribution functions) description of the proton. The experiment was conducted in Hall A of Thomas Jefferson National Accelerator Facility(Jefferson Lab). It used a polarized and unpolarized electron beam, a 6% copper radiator with the thickness of 6.1% radiation lengths (to produce a bremsstrahlung photon beam), the Hall A liquid hydrogen target, a high resolution spectrometer with a focal plane polarimeter, and a photon hodoscope calorimeter. Results of the differential cross sections are presented, and discussed in the general context of the scientific motivation.

Sum rules across the unpolarized Compton processes involving generalized polarizabilities and moments of nucleon structure functions

Science.gov (United States)

Lensky, Vadim; Hagelstein, Franziska; Pascalutsa, Vladimir; Vanderhaeghen, Marc

2018-04-01

We derive two new sum rules for the unpolarized doubly virtual Compton scattering process on a nucleon, which establish novel low-Q2 relations involving the nucleon's generalized polarizabilities and moments of the nucleon's unpolarized structure functions F1(x ,Q2) and F2(x ,Q2). These relations facilitate the determination of some structure constants which can only be accessed in off-forward doubly virtual Compton scattering, not experimentally accessible at present. We perform an empirical determination for the proton and compare our results with a next-to-leading-order chiral perturbation theory prediction. We also show how these relations may be useful for a model-independent determination of the low-Q2 subtraction function in the Compton amplitude, which enters the two-photon-exchange contribution to the Lamb shift of (muonic) hydrogen. An explicit calculation of the Δ (1232 )-resonance contribution to the muonic-hydrogen 2 P -2 S Lamb shift yields -1 ±1 μ eV , confirming the previously conjectured smallness of this effect.

Compact FEL-driven inverse compton scattering gamma-ray source

Energy Technology Data Exchange (ETDEWEB)

Placidi, M. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Di Mitri, S., E-mail: simone.dimitri@elettra.eu [Elettra - Sincrotrone Trieste S.C.p.A., 34149 Basovizza, Trieste (Italy); Pellegrini, C. [SLAC National Accelerator Laboratory, Menlo Park, CA 94025 (United States); University of California, Los Angeles, CA 90095 (United States); Penn, G. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

2017-05-21

Many research and applications areas require photon sources capable of producing gamma-ray beams in the multi-MeV energy range with reasonably high fluxes and compact footprints. Besides industrial, nuclear physics and security applications, a considerable interest comes from the possibility to assess the state of conservation of cultural assets like statues, columns etc., via visualization and analysis techniques using high energy photon beams. Computed Tomography scans, widely adopted in medicine at lower photon energies, presently provide high quality three-dimensional imaging in industry and museums. We explore the feasibility of a compact source of quasi-monochromatic, multi-MeV gamma-rays based on Inverse Compton Scattering (ICS) from a high intensity ultra-violet (UV) beam generated in a free-electron laser by the electron beam itself. This scheme introduces a stronger relationship between the energy of the scattered photons and that of the electron beam, resulting in a device much more compact than a classic ICS for a given scattered energy. The same electron beam is used to produce gamma-rays in the 10–20 MeV range and UV radiation in the 10–15 eV range, in a ~4×22 m{sup 2} footprint system.

Compton Scattering Cross Section on the Proton at High Momentum Transfer

International Nuclear Information System (INIS)

A. Danagoulian; V.H. Mamyan; M. Roedelbronn; K.A. Aniol; J.R.M. Annand; P.Y. Bertin; L. Bimbot; P. Bosted; J.R. Calarco; A. Camsonne; C.C. Chang; T.-H. Chang; J.-P. Chen; Seonho Choi; E. Chudakov; P. Degtyarenko; C.W. de Jager; A. Deur; D. Dutta; K. Egiyan; H. Gao; F. Garibaldi; O. Gayou; R. Gilman; A. Glamazdin; C. Glashausser; J. Gomez; D.J. Hamilton; J.-O. Hansen; D. Hayes; D.W. Higinbotham; W. Hinton; T. Horn; C. Howell; T. Hunyady; C.E. Hyde-Wright; X. Jiang; M.K. Jones; M. Khandaker; A. Ketikyan; V. Koubarovski; K. Kramer; G. Kumbartzki; G. Laveissiere; J. LeRose; R.A. Lindgren; D.J. Margaziotis; P. Markowitz; K. McCormick; Z.-E. Meziani; R. Michaels; P. Moussiegt; S. Nanda; A.M. Nathan; D.M. Nikolenko; V. Nelyubin; B.E. Norum; K. Paschke; L. Pentchev; C.F. Perdrisat; E. Piasetzky; R. Pomatsalyuk; V.A. Punjabi; I. Rachek; A. Radyushkin; B. Reitz; R. Roche; G. Ron; F. Sabatie; A. Saha; N. Savvinov; A. Shahinyan; Y. Shestakov; S. Sirca; K. Slifer; P. Solvignon; P. Stoler; S. Tajima; V. Sulkosky; L. Todor; B. Vlahovic; L.B. Weinstein; K. Wang; B. Wojtsekhowski; H. Voskanyan; H. Xiang; X. Zheng; L. Zhu

2007-01-01

Cross-section values for Compton scattering on the proton were measured at 25 kinematic settings over the range s = 5-11 and -t = 2-7 GeV2 with statistical accuracy of a few percent. The scaling power for the s-dependence of the cross section at fixed center of mass angle was found to be 8.0 +/- 0.2, strongly inconsistent with the prediction of perturbative QCD. The observed cross section values are in fair agreement with the calculations using the handbag mechanism, in which the external photons couple to a single quark

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

Attenuation studies near K-absorption edges using Compton scattered 241Am gamma rays

International Nuclear Information System (INIS)

Abdullah, K.K.; Ramachandran, N.; Karunakaran Nair, K.; Babu, B.R.S.; Joseph, Antony; Thomas, Rajive; Varier, K.M.

2008-01-01

We have carried out photon attenuation measurements at several energies in the range from 49.38 keV to 57.96 keV around the K-absorption edges of the rare earth elements Sm, Eu, Gd, Tb, Dy and Er using 59.54 keV gamma rays from 241 Am source after Compton scattering from an aluminium target. Pellets of oxides of the rare earth elements were chosen as mixture absorbers in these investigations. A narrow beam good geometry set-up was used for the attenuation measurements. The scattered gamma rays were detected by an HPGe detector. The results are consistent with theoretical values derived from the XCOM package. (author)

MICROBUNCH TEMPORAL DIAGNOSTIC BY COMPTON SCATTERING IN INTERFERING LASER BEAMS

International Nuclear Information System (INIS)

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

1998-01-01

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

Measurement of the cross section for forward Compton scattering by /sup 4//sub 2/ He nuclei at energies E/sub. gamma. / = 1. 8--3. 8 GeV

Energy Technology Data Exchange (ETDEWEB)

Aleksanyan, A.S.; Babayan, G.E.; Voskanyan, A.V.; Gasparyan, A.D.; Gevorkyan, S.R.; Karapetyan, S.N.; Ketikyan, A.Z.; Megrabyan, G.K.; Movsisyan, K.A.; Oganesyan, G.A.; and others

1987-04-01

The differential cross sections for Compton scattering by nuclei of /sup 4//sub 2/ He have been measured at the momentum transfers 0.02less than or equal tochemically bondtchemically bond<0.14 (GeV/c)/sup 2/ in the energy region E/sub ..gamma../ = 1.8--3.8 GeV. On the basis of the diffraction theory of multiple scattering the values of the differential cross sections at t = 0, of the slope parameters of the diffraction cone, and of the /sup 4//sub 2/ He nucleus radius have been determined. Experimental values are given for the phase of the scattering amplitude by nucleons, ..cap alpha..( f/sup 0//sub i/) = Re f/sup 0//sub i// Im f/sup 0//sub i/. On the basis of the differential cross sections at t = 0 the total photoabsorption cross section and the photon screening coefficient are determined for the /sup 4//sub 2/ He nucleus.

Doppler Broadening Calculations of Compton Scattering for Molecules, Plastics, Tissues, and Few Biological Materials in the X-Ray Region: An Analysis in Terms of Compton Broadening and Geometrical Energy Broadening

Science.gov (United States)

Rao, D. V.; Cesareo, R.; Brunetti, A.; Gigante, G. E.; Akatsuka, T.; Takeda, T.; Itai, Y.

2004-09-01

Relativistic and nonrelativistic Compton profile cross sections for H, C, N, O, P, and Ca and for a few important biological materials such as water, polyethylene, lucite, polystyrene, nylon, polycarbonate, bakelite, fat, bone and calcium hydroxyapatite are estimated for a number of Kα x-ray energies and for 59.54 keV (Am-241) γ photons. Energy broadening and geometrical broadening (ΔG) is estimated by assuming θmin and θmax are symmetrically situated around θ=90°. FWHM of J(PZ) and FWHM of Compton energy broadening are evaluated at various incident photon energies. These values are estimated around the centroid of the Compton profile with an energy interval of 0.1 and 1.0 keV for 59.54 keV photons. Total Compton, individual shell, and Compton energy-absorption scattering cross sections are evaluated in the energy region from 0.005 to 0.5 MeV. It is an attempt to know the effect of Doppler broadening for single atoms, many of which constitute the biological materials.

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

Virtual compton scattering on the proton below pion threshold

Energy Technology Data Exchange (ETDEWEB)

Bertin, P.Y.; VCS Collaboration

1995-12-31

This paper presents the preliminary results of an electron-proton interaction experiment carried out with the accelerator of MAMI at Mainz (Germany) for the recording of virtual compton scattering events. More than 2 10{sup 4} events were recorded in a two days run with a liquid hydrogen target. The main limitation for the counting rate comes from the limitation of the acquisition rate (100 Hz) and the single rates (10{sup 5}) in the drift chambers. The aim of this experiment is the understanding of both the low energy expansion and the generalized polarizabilities in order to compare, confirm or exclude the models of Quantum Chromodynamics used for the understanding of the nucleon. (J.S.). 3 refs., 5 figs.

Compton spectra of atoms at high x-ray intensity

Science.gov (United States)

Son, Sang-Kil; Geffert, Otfried; Santra, Robin

2017-03-01

Compton scattering is the nonresonant inelastic scattering of an x-ray photon by an electron and has been used to probe the electron momentum distribution in gas-phase and condensed-matter samples. In the low x-ray intensity regime, Compton scattering from atoms dominantly comes from bound electrons in neutral atoms, neglecting contributions from bound electrons in ions and free (ionized) electrons. In contrast, in the high x-ray intensity regime, the sample experiences severe ionization via x-ray multiphoton multiple ionization dynamics. Thus, it becomes necessary to take into account all the contributions to the Compton scattering signal when atoms are exposed to high-intensity x-ray pulses provided by x-ray free-electron lasers (XFELs). In this paper, we investigate the Compton spectra of atoms at high x-ray intensity, using an extension of the integrated x-ray atomic physics toolkit, xatom. As the x-ray fluence increases, there is a significant contribution from ionized electrons to the Compton spectra, which gives rise to strong deviations from the Compton spectra of neutral atoms. The present study provides not only understanding of the fundamental XFEL-matter interaction but also crucial information for single-particle imaging experiments, where Compton scattering is no longer negligible. , which features invited work from the best early-career researchers working within the scope of J. Phys. B. This project is part of the Journal of Physics series’ 50th anniversary celebrations in 2017. Sang-Kil Son was selected by the Editorial Board of J. Phys. B as an Emerging Leader.

Aspects of forward scattering from the compression paddle in the dosimetry of mammography

International Nuclear Information System (INIS)

Toroi, Paula; Koenoenen, Niina; Timonen, Marjut; Kortesniemi, Mika

2013-01-01

The best compression paddle position during air kerma measurement in mammography dosimetry was studied. The amount of forward scattering as a function of the compression paddle distance was measured with different X-ray spectra and different types of paddles and dose meters. The contribution of forward scattering to the air kerma did not present significant dependency on the beam quality or of the compression paddle type. The tested dose meter types detected different amounts of forward scattering due to different internal collimation. When the paddle was adjusted to its maximum clinical distance, the proportion of the detected forward scattering was only 1 % for all dose meter types. The most consistent way of performing air kerma measurements is to position the compression paddle at the maximum distance from the dose meter and use a constant forward scattering factor for all dose meters. Thus, the dosimetric uncertainty due to the forward scatter can be minimised. (authors)

Compton-scattering from hydrogen, deuterium and complex nuclei at photonenergies of 3 and 5 Gev under very small scattering angles

International Nuclear Information System (INIS)

Kahl, T.

1976-01-01

Compton scattering on hydrogen, deuterium and heavy nuclei up to hold was studied at very small momentum transfer and at two energies. Measurements were carried out in the region 0.002LT= /t/ LT=0.06 (GeV/c)**2 at 5 GeV and in the region 0.001 LT=/t/LT=0.02 (GeV/c)**2 at 3 GeV. (orig.) [de

Compton Scattering from the Deuteron at Low Energies

Energy Technology Data Exchange (ETDEWEB)

Lundin, Magnus [Lund Univ. (Sweden). Dept. of Physics

2002-05-01

A series of three Compton scattering experiments on deuterium have been performed at the high-resolution tagged-photon facility MAX-lab located in Lund, Sweden. The 50 < E{sub g} < 70 MeV tagged photons were scattered from a liquid deuterium target and detected simultaneously in three (10{sup x}10{sup )} NaI detectors. The average laboratory angles investigated were 45, 125 and 135 deg. The influence of the inelastic contribution was minimized by implementing a narrow elastic fit-region in the missing energy spectra. Absolute cross sections were extracted for average photon energies of 55 and 66 MeV at each angle and for each experiment. The extracted cross sections are in good agreement with those measured at Illinois by Lucas et al. The difference between the electric and magnetic isospin-averaged polarizabilities of the nucleon inside the deuteron, was varied within the calculations of Levchuk and L'vov to best reproduce the data, holding the sum fixed at 14.6 (10{sup -4} fm{sup 3}). The result implies that the electric polarizability of the neutron is the same as that of the proton within the experimental uncertainties. The result also indicates that the magnetic polarizability of the neutron is larger than that of the proton.

X-ray Compton scattering experiments for fluid alkali metals at high temperatures and pressures

Energy Technology Data Exchange (ETDEWEB)

Matsuda, K., E-mail: kazuhiro-matsuda@scphys.kyoto-u.ac.jp; Fukumaru, T.; Kimura, K.; Yao, M. [Graduate School of Science, Kyoto University, Kyoto 606-8502 (Japan); Tamura, K. [Graduate School of Engineering, Kyoto University, Kyoto 606-8502 (Japan); Katoh, M. [A.L.M.T. Corp., Iwasekoshi-Machi 2, Toyama 931-8543 (Japan); Kajihara, Y.; Inui, M. [Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima 739-8521 (Japan); Itou, M.; Sakurai, Y. [Japan Synchrotron Radiation Research Institute, SPring-8, 1-1-1 Kouto, Sayo, Hyogo 679-5198 (Japan)

2015-08-17

We have developed a high-pressure vessel and a cell for x-ray Compton scattering measurements of fluid alkali metals. Measurements have been successfully carried out for alkali metal rubidium at elevated temperatures and pressures using synchrotron radiation at SPring-8. The width of Compton profiles (CPs) of fluid rubidium becomes narrow with decreasing fluid density, which indicates that the CPs sensitively detect the effect of reduction in the valence electron density. At the request of all authors of the paper, and with the agreement of the Proceedings Editor, an updated version of this article was published on 10 September 2015. The original article supplied to AIP Publishing was not the final version and contained PDF conversion errors in Formulas (1) and (2). The errors have been corrected in the updated and re-published article.

Quantum characteristics of occurrence scattering time in two-component non-ideal plasmas

Energy Technology Data Exchange (ETDEWEB)

Hong, Woo-Pyo [Department of Electronics Engineering, Catholic University of Daegu, Hayang, 712-702 (Korea, Republic of); Jung, Young-Dae, E-mail: ydjung@hanyang.ac.kr [Department of Applied Physics and Department of Bionanotechnology, Hanyang University, Ansan, Kyunggi-Do 15588 (Korea, Republic of); Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 12180-3590 (United States)

2015-10-30

The quantum diffraction and plasma screening effects on the occurrence time for the collision process are investigated in two-component non-ideal plasmas. The micropotential model taking into account the quantum diffraction and screening with the eikonal analysis is employed to derive the occurrence time as functions of the collision energy, density parameter, Debye length, de Broglie wavelength, and scattering angle. It is shown that the occurrence time for forward scattering directions decreases the tendency of time-advance with increasing scattering angle and de Broglie wavelength. However, it is found that the occurrence time shows the oscillatory time-advance and time-retarded behaviors with increasing scattering angle. It is found that the plasma screening effect enhances the tendency of time-advance on the occurrence time for forward scattering regions. It is also shown the quantum diffraction effect suppresses the occurrence time advance for forward scattering angles. In addition, it is shown that the occurrence time advance decreases with an increase of the collision energy. - Highlights: • The quantum diffraction and screening effects on the occurrence scattering time are investigated in non-ideal plasmas. • It is shown the quantum diffraction effect suppresses the occurrence time advance for forward scattering angles. • It is found that the plasma screening effect enhances the tendency of time-advance on the occurrence time.

Image combination enhancement method for X-ray compton back-scattering security inspection body scanner

International Nuclear Information System (INIS)

Wang Huaiying; Zhang Yujin; Yang Lirui; Li Dong

2011-01-01

As for X-ray Compton Back-Scattering (CBS) body scanner, image clearness is very important for the performance of detecting the contraband hidden on the body. A new image combination enhancement method is provided based on characteristics of CBS body images and points of human vision. After processed by this method, the CBS image will be obviously improved with clear levels, distinct outline and uniform background. (authors)

X-Band Linac Beam-Line for Medical Compton Scattering X-Ray Source

CERN Document Server

Dobashi, Katsuhiro; Ebina, Futaro; Fukasawa, Atsushi; Hayano, Hitoshi; Higo, Toshiyasu; Kaneyasu, Tatsuo; Ogino, Haruyuki; Sakamoto, Fumito; Uesaka, Mitsuru; Urakawa, Junji; Yamamoto, Tomohiko

2005-01-01

Compton scattering hard X-ray source for 10~80 keV are under construction using the X-band (11.424 GHz) electron linear accelerator and YAG laser at Nuclear Engineering Research laboratory, University of Tokyo. This work is a part of the national project on the development of advanced compact medical accelerators in Japan. National Institute for Radiological Science is the host institute and U. Tokyo and KEK are working for the X-ray source. Main advantage is to produce tunable monochromatic hard ( 10-80

Colour coherence in deep inelastic Compton scattering

Energy Technology Data Exchange (ETDEWEB)

Lebedev, A.I.; Vazdik, J.A. (Lebedev Physical Inst., Academy of Sciences, Moscow (USSR))

1992-01-01

MC simulation of Deep Inelastic Compton on proton - both QED and QCD - was performed on the basis of LUCIFER program for HERA energies. Charged hadron flow was calculated for string and independent fragmentation with different cuts on p{sub t} and x. It is shown that interjet colour coherence leads in the case of QCD Compton to the drag effects diminishing the hadron flow in the direction between quark jet and proton remnant jet. (orig.).

Colour coherence in deep inelastic Compton scattering

International Nuclear Information System (INIS)

Lebedev, A.I.; Vazdik, J.A.

1992-01-01

MC simulation of Deep Inelastic Compton on proton - both QED and QCD - was performed on the basis of LUCIFER program for HERA energies. Charged hadron flow was calculated for string and independent fragmentation with different cuts on p t and x. It is shown that interjet colour coherence leads in the case of QCD Compton to the drag effects diminishing the hadron flow in the direction between quark jet and proton remnant jet. (orig.)

Induced Compton scattering of a laser in an inhomogeneous plasma

International Nuclear Information System (INIS)

Liu, C.S.; Tripathi, V. K.

2003-01-01

A laser propagating through a high temperature low density plasma undergoes induced Compton backscattering involving the coupling of the laser pump and the scattered electromagnetic wave via the resonant electrons or the resistive quasimode. The region of nonlinear interaction is localized due to plasma inhomogeneity. At short density scale lengths when the interaction region is strongly localized and resonant electrons quickly move out of it, the electron distribution function remains Maxwellian and Compton reflectivity is significant at laser intensity >10 16 W/cm 2 . In gentle density gradients the resonant electrons are trapped in the ponderomotive and self-consistent potential well of the quasimode as they enter the interaction region. The ones with velocity v z p (v p being the phase velocity of the ponderomotive wave propagating along z direction) are accelerated to v p while those with v z >v p are retarded to v p . Since the number of the former is more than that of the latter there is a net momentum transfer to electrons. Momentum and action conservation lead to a reflectivity, R, that initially goes as the square of pump intensity, then rises gradually at higher intensity. R decreases rapidly with v th /v p , where v th is the thermal velocity of electrons

Determination of the X-ray mass absorption coefficient by measurement of the intensity of AgKα Compton scattered radiation

International Nuclear Information System (INIS)

Franzini, M.; Leoni, L.; Saitta, M.

1976-01-01

By utilizing a reflection geometry, an accurate mass absorption coefficient of a sample can be determined by measuring the Ag Kα Compton intensity. Intensities of Ag Kα Compton scattered radiation have been collected by using either the usual reflection geometry of a Philips PW 1450 automatic x-ray spectrometer or a more refined reflection geometry, achieved on a Philips PW 1540/10A manual x-ray spectrometer. The experimental results have shown that the relationship between the Ag Kα Compton intensity and the mass absorption is a logarithmic function. The experimental results are not in agreement with those reported in literature, but a theoretical explanation to account for this fact has not been achieved as yet. (author)

Geometric Design of Scalable Forward Scatterers for Optimally Efficient Solar Transformers.

Science.gov (United States)

Kim, Hye-Na; Vahidinia, Sanaz; Holt, Amanda L; Sweeney, Alison M; Yang, Shu

2017-11-01

It will be ideal to deliver equal, optimally efficient "doses" of sunlight to all cells in a photobioreactor system, while simultaneously utilizing the entire solar resource. Backed by the numerical scattering simulation and optimization, here, the design, synthesis, and characterization of the synthetic iridocytes that recapitulated the salient forward-scattering behavior of the Tridacnid clam system are reported, which presents the first geometric solution to allow narrow, precise forward redistribution of flux, utilizing the solar resource at the maximum quantum efficiency possible in living cells. The synthetic iridocytes are composed of silica nanoparticles in microspheres embedded in gelatin, both are low refractive index materials and inexpensive. They show wavelength selectivity, have little loss (the back-scattering intensity is reduced to less than ≈0.01% of the forward-scattered intensity), and narrow forward scattering cone similar to giant clams. Moreover, by comparing experiments and theoretical calculation, it is confirmed that the nonuniformity of the scatter sizes is a "feature not a bug" of the design, allowing for efficient, forward redistribution of solar flux in a micrometer-scaled paradigm. This method is environmentally benign, inexpensive, and scalable to produce optical components that will find uses in efficiency-limited solar conversion technologies, heat sinks, and biofuel production. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Compton scattering on the γ-α phase transition in cerium

International Nuclear Information System (INIS)

Kornstaedt, U.

1979-07-01

Compton profiles for γ- and α-Cer were measured using Cr51 as a γ-radiation source. The experimental profiles have been corrected for multiple scattering by Monte-Carlo techniques. The corrected profiles are compared with theoretical profiles which are calculated on the basis of the renormalized free atom model for 6s electrons and the tight-binding model of 4f and 5d electrons. The experimental results show clearly that the promotional model is not valid. Instead a possible explanation for the observed phase transition may be a Mott transition. To better determine this, improved electron wave functions, such as might be obtained by band structure calculations, are needed. (orig.) [de

Compton recoil electron tracking with silicon strip detectors

International Nuclear Information System (INIS)

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

1992-01-01

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

Corrections for the effects of accidental coincidences, Compton scatter, and object size in positron emission mammography (PEM) imaging

Energy Technology Data Exchange (ETDEWEB)

Raymond Raylman; Stanislaw Majewski; Randolph Wojcik; Andrew Weisenberger; Brian Kross; Vladimir Popov

2001-06-01

Positron emission mammography (PEM) has begun to show promise as an effective method for the detection of breast lesions. Due to its utilization of tumor-avid radiopharmaceuticals labeled with positron-emitting radionuclides, this technique may be especially useful in imaging of women with radiodense or fibrocystic breasts. While the use of these radiotracers affords PEM unique capabilities, it also introduces some limitations. Specifically, acceptance of accidental and Compton-scattered coincidence events can decrease lesion detectability. The authors studied the effect of accidental coincidence events on PEM images produced by the presence of 18F-Fluorodeoxyglucose in the organs of a subject using an anthropomorphic phantom. A delayed-coincidence technique was tested as a method for correcting PEM images for the occurrence of accidental events. Also, a Compton scatter correction algorithm designed specifically for PEM was developed and tested using a compressed breast phantom.

Corrections for the effects of accidental coincidences, Compton scatter, and object size in positron emission mammography (PEM) imaging

International Nuclear Information System (INIS)

Raymond Raylman; Stanislaw Majewski; Randolph Wojcik; Andrew Weisenberger; Brian Kross; Vladimir Popov

2001-01-01

Positron emission mammography (PEM) has begun to show promise as an effective method for the detection of breast lesions. Due to its utilization of tumor-avid radiopharmaceuticals labeled with positron-emitting radionuclides, this technique may be especially useful in imaging of women with radiodense or fibrocystic breasts. While the use of these radiotracers affords PEM unique capabilities, it also introduces some limitations. Specifically, acceptance of accidental and Compton-scattered coincidence events can decrease lesion detectability. The authors studied the effect of accidental coincidence events on PEM images produced by the presence of 18F-Fluorodeoxyglucose in the organs of a subject using an anthropomorphic phantom. A delayed-coincidence technique was tested as a method for correcting PEM images for the occurrence of accidental events. Also, a Compton scatter correction algorithm designed specifically for PEM was developed and tested using a compressed breast phantom

Measurement of deeply virtual Compton scattering using the ZEUS detector at HERA

International Nuclear Information System (INIS)

Grabowska-Bold, I.

2004-08-01

The cross sections for deeply virtual compton scattering in the reaction ep → e'γp' has been measured with the ZEUS detector at HERA using integrated luminosities of 95 pb -1 of e + p and 17 pb -1 of e - p collisions. Cross sections are presented as a function of the exchanged photon virtuality, Q 2 , and the centre-of-mass energy, W, of the γ * p system in the region 5 2 2 and 40 < W < 140 GeV. The obtained results are compared to QCD-based calculations. (orig.)

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

Angle-averaged Compton cross sections

International Nuclear Information System (INIS)

Nickel, G.H.

1983-01-01

The scattering of a photon by an individual free electron is characterized by six quantities: α = initial photon energy in units of m 0 c 2 ; α/sub s/ = scattered photon energy in units of m 0 c 2 ; β = initial electron velocity in units of c; phi = angle between photon direction and electron direction in the laboratory frame (LF); theta = polar angle change due to Compton scattering, measured in the electron rest frame (ERF); and tau = azimuthal angle change in the ERF. We present an analytic expression for the average of the Compton cross section over phi, theta, and tau. The lowest order approximation to this equation is reasonably accurate for photons and electrons with energies of many keV

Angle-averaged Compton cross sections

Energy Technology Data Exchange (ETDEWEB)

Nickel, G.H.

1983-01-01

The scattering of a photon by an individual free electron is characterized by six quantities: ..cap alpha.. = initial photon energy in units of m/sub 0/c/sup 2/; ..cap alpha../sub s/ = scattered photon energy in units of m/sub 0/c/sup 2/; ..beta.. = initial electron velocity in units of c; phi = angle between photon direction and electron direction in the laboratory frame (LF); theta = polar angle change due to Compton scattering, measured in the electron rest frame (ERF); and tau = azimuthal angle change in the ERF. We present an analytic expression for the average of the Compton cross section over phi, theta, and tau. The lowest order approximation to this equation is reasonably accurate for photons and electrons with energies of many keV.

Deeply Virtual Compton Scattering Studies at Jefferson Lab

International Nuclear Information System (INIS)

Sabatie, F.

2010-11-01

This document describes the early experimental effort at Jefferson Lab to unravel the Generalized Parton Distributions (GPD), using the Deeply Virtual Compton Scattering (DVCS) process. The GPDs contain the usual form factors and parton distribution functions, but in addition, they include correlations between states of different longitudinal and transverse momenta. They therefore give access to a three-dimensional picture of the nucleon. DVCS is the cleanest process allowing to extract GPDs, and as early as 2000, a number of experiments were proposed for this purpose. The results of the first exploratory experiments are presented as well as the first measurements of linear combinations of GPDs. In addition, a thorough discussion on the insights gained from these early experiments is proposed, linked with the theoretical tools used to extract GPDs from DVCS data. Finally, improvements on what was done for this first experimental phase are proposed and discussed, and new proposals and measurements are described. (author)

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.)

Deeply Virtual Compton Scattering and its Beam Charge Asymmetry in $e^{\\pm} p$ Collisions at HERA

CERN Document Server

Aaron, F.D.; Alexa, C.; Alimujiang, K.; Andreev, V.; Antunovic, B.; Backovic, S.; Baghdasaryan, A.; Barrelet, E.; Bartel, W.; Begzsuren, K.; Belousov, A.; Bizot, J.C.; Boudry, V.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Bruncko, D.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Cantun Avila, K.B.; Cerny, K.; Cerny, V.; Chekelian, V.; Cholewa, A.; Contreras, J.G.; Coughlan, J.A.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Daum, K.; Deak, M.; de Boer, Y.; Delcourt, B.; Del Degan, M.; Delvax, J.; De Wolf, E.A.; Diaconu, C.; Dodonov, V.; Dossanov, A.; Dubak, A.; Eckerlin, G.; Efremenko, V.; Egli, S.; Eliseev, A.; Elsen, E.; Falkiewicz, A.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Fischer, D.-J.; Fleischer, M.; Fomenko, A.; Gabathuler, E.; Gayler, J.; Ghazaryan, Samvel; Glazov, A.; Glushkov, I.; Goerlich, L.; Gogitidze, N.; Gouzevitch, M.; Grab, C.; Greenshaw, T.; Grell, B.R.; Grindhammer, G.; Habib, S.; Haidt, D.; Helebrant, C.; Henderson, R.C.W.; Hennekemper, E.; Henschel, H.; Herbst, M.; Herrera, G.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hreus, T.; Jacquet, M.; Janssen, M.E.; Janssen, X.; Jonsson, L.; Jung, Andreas Werner; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I.R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Kluge, T.; Knutsson, A.; Kogler, R.; Kostka, P.; Kraemer, M.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Kruger, K.; Kutak, K.; Landon, M.P.J.; Lange, W.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Li, G.; Lipka, K.; Liptaj, A.; List, B.; List, J.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Makankine, A.; Malinovski, E.; Marage, P.; Marti, Ll.; Martyn, H.-U.; Maxfield, S.J.; Mehta, A.; Meyer, A.B.; Meyer, H.; Meyer, H.; Meyer, J.; Michels, V.; Mikocki, S.; Milcewicz-Mika, I.; Moreau, F.; Morozov, A.; Morris, J.V.; Mozer, Matthias Ulrich; Mudrinic, M.; Muller, K.; Murin, P.; Naumann, Th.; Newman, P.R.; Niebuhr, C.; Nikiforov, A.; Nikitin, D.; Nowak, G.; Nowak, K.; Nozicka, M.; Olivier, B.; Olsson, J.E.; Osman, S.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Pandurovic, M.; Papadopoulou, Th.; Pascaud, C.; Patel, G.D.; Pejchal, O.; Perez, E.; Petrukhin, A.; Picuric, I.; Piec, S.; Pitzl, D.; Placakyte, R.; Pokorny, B.; Polifka, R.; Povh, B.; Radescu, V.; Rahmat, A.J.; Raicevic, N.; Raspiareza, A.; Ravdandorj, T.; Reimer, P.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rotaru, M.; Ruiz Tabasco, J.E.; Rurikova, Z.; Rusakov, S.; Salek, D.; Sankey, D.P.C.; Sauter, M.; Sauvan, E.; Schmitt, S.; Schoeffel, L.; Schoning, A.; Schultz-Coulon, H.-C.; Sefkow, F.; Shaw-West, R.N.; Shtarkov, L.N.; Shushkevich, S.; Sloan, T.; Smiljanic, Ivan; Soloviev, Y.; Sopicki, P.; South, D.; Spaskov, V.; Specka, Arnd E.; Staykova, Z.; Steder, M.; Stella, B.; Stoicea, G.; Straumann, U.; Sunar, D.; Sykora, T.; Tchoulakov, V.; Thompson, G.; Thompson, P.D.; Toll, T.; Tomasz, F.; Tran, T.H.; Traynor, D.; Trinh, T.N.; Truol, P.; Tsakov, I.; Tseepeldorj, B.; Turnau, J.; Urban, K.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Vinokurova, S.; Volchinski, V.; von den Driesch, M.; Wegener, D.; Wissing, Ch.; Wunsch, E.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.; Zus, R.

2009-01-01

A measurement of elastic deeply virtual Compton scattering gamma* p -> gamma p using e^+ p and e^- p collision data recorded with the H1 detector at HERA is presented. The analysed data sample corresponds to an integrated luminosity of 306 pb^-1, almost equally shared between both beam charges. The cross section is measured as a function of the virtuality Q^2 of the exchanged photon and the centre-of-mass energy W of the gamma* p system in the kinematic domain 6.5 < Q^2 < 80 GeV^2, 30 < W < 140 GeV and |t| < 1 GeV^2, where t denotes the squared momentum transfer at the proton vertex. The cross section is determined differentially in t for different Q^2 and W values and exponential t-slope parameters are derived. Using e^+ p and e^- p data samples, a beam charge asymmetry is extracted for the first time in the low Bjorken x kinematic domain. The observed asymmetry is attributed to the interference between Bethe-Heitler and deeply virtual Compton scattering processes. Experimental results are dis...

A detector for tomography by Compton scattering at 900 and tomography apparatus comprising such detector

International Nuclear Information System (INIS)

Ricodeau, Jean.

1981-01-01

The present invention concerns a detector for tomography by Compton scattering at 90 0 . The difference between this detector and those currently used previously lies in the fact that the collection aperture of the radiation at normal angle to the incident beam is large and can reach 180 0 and even more. This fact allows to collect an important part of the scattered radiation. A good image quality is obtained with low radiation doses delivered to the body as compared to previous techniques. This detector can be operated in analogical mode which presents the advantage to be faster and easier to realize [fr

Longitudinal target-spin azimuthal asymmetry in Deeply-Virtual Compton Scattering

Energy Technology Data Exchange (ETDEWEB)

Kopytin, M.

2006-08-22

As a generalization of the usual Parton Distribution Functions (PDFs) Generalized Parton Distributions (GPDs), introduced a decade ago, contain additional information about quark and gluon distributions in the plane transverse to the direction of motion of the nucleon. Strong interest in GPDs was triggered by the work of X. Ji who demonstrated that in the forward limit GPDs can give information about the total angular momentum carried by quarks (gluons) in the nucleon. The hard exclusive electroproduction of a real photon, called Deeply Virtual Compton Scattering (DVCS), appears to be the theoretically cleanest way to access GPDs experimentally. This process has a final state identical to that of the Bethe-Heitler (BH) process where the photon is radiated from either incoming or outgoing lepton. Both processes are experimentally indistinguishable as their amplitudes interfere. The interference term involves linearly the amplitudes of the DVCS process giving access to GPDs. In this thesis results from HERMES are reported on an azimuthal asymmetry with respect to the spin of the proton target, which is attributed to the interference between the Bethe-Heitler process and the DVCS process. The asymmetry, also referred to as the longitudinal target-spin asymmetry (LTSA), gives access mainly to the polarized GPD H. The kinematic dependences of the LTSA on t, x{sub B} and Q{sup 2} are measured and compared with the corresponding measurements on the deuteron. The results are compared with theoretical calculations and with the recent CLAS measurements. The data, used for analysis in this thesis, have been accumulated by the HERMES experiment at DESY scattering the HERA 27.6 GeV positron beam off hydrogen and deuterium gas targets. Additionally, production tests of the HELIX128 3.0 chip are discussed. The chip is the frontend readout chip of the silicon recoil detector. The latter is a part of the HERMES recoil detector, which is built around the target area in order to

Longitudinal target-spin azimuthal asymmetry in Deeply-Virtual Compton Scattering

International Nuclear Information System (INIS)

Kopytin, M.

2006-01-01

As a generalization of the usual Parton Distribution Functions (PDFs) Generalized Parton Distributions (GPDs), introduced a decade ago, contain additional information about quark and gluon distributions in the plane transverse to the direction of motion of the nucleon. Strong interest in GPDs was triggered by the work of X. Ji who demonstrated that in the forward limit GPDs can give information about the total angular momentum carried by quarks (gluons) in the nucleon. The hard exclusive electroproduction of a real photon, called Deeply Virtual Compton Scattering (DVCS), appears to be the theoretically cleanest way to access GPDs experimentally. This process has a final state identical to that of the Bethe-Heitler (BH) process where the photon is radiated from either incoming or outgoing lepton. Both processes are experimentally indistinguishable as their amplitudes interfere. The interference term involves linearly the amplitudes of the DVCS process giving access to GPDs. In this thesis results from HERMES are reported on an azimuthal asymmetry with respect to the spin of the proton target, which is attributed to the interference between the Bethe-Heitler process and the DVCS process. The asymmetry, also referred to as the longitudinal target-spin asymmetry (LTSA), gives access mainly to the polarized GPD H. The kinematic dependences of the LTSA on t, x B and Q 2 are measured and compared with the corresponding measurements on the deuteron. The results are compared with theoretical calculations and with the recent CLAS measurements. The data, used for analysis in this thesis, have been accumulated by the HERMES experiment at DESY scattering the HERA 27.6 GeV positron beam off hydrogen and deuterium gas targets. Additionally, production tests of the HELIX128 3.0 chip are discussed. The chip is the frontend readout chip of the silicon recoil detector. The latter is a part of the HERMES recoil detector, which is built around the target area in order to detect the

Compton radiography, 3. Compton scinti-tomography of the chest diseases

Energy Technology Data Exchange (ETDEWEB)

Okuyama, S; Sera, K; Shishido, F; Fukuda, H [Tohoku Univ., Sendai (Japan). Research Inst. for Tuberculosis, Leprosy and Cancer; Mishina, H

1977-10-01

The compton radiography aims at collection of depth information by recording with a scinticamera those Compton rays that have resulted from scattering of a monoenergetic gamma beam by a volume of interest. Appreciably clear clinical scinti-tomograms were obtained of the chest wall, and intrathoracic structures such as the lungs, intrapulmonary pathologies, and mediastinum. This was achieved without any computer assistance for image reconstruction such as those in the case of XCT. Apparently, suitable corrections of the attenuations of the primary monoenergetic gamma rays and secondary Compton rays would greatly improve the image quality, and imaging time and radiation exposure as well. This technic is simple in principle, relatively cheap, and yet prospective of development of stereoptic fluoroscopy that would be extremely helpful in guiding such procedures as visceral biopsies.

Fermi surface of a disordered Cu-Al -alloy single crystal studied by high-resolution Compton scattering and electron diffraction

Science.gov (United States)

Kwiatkowska, J.; Maniawski, F.; Matsumoto, I.; Kawata, H.; Shiotani, N.; Lityńska, L.; Kaprzyk, S.; Bansil, A.

2004-08-01

We have measured high resolution Compton scattering profiles for momentum transfer along a series of 28 independent directions from Cu0.842Al0.158 disordered alloy single crystals with normals to the surfaces oriented along the [100], [110], and [111] directions. The experimental spectra are interpreted via parallel first-principles KKR-CPA (Korringa-Kohn-Rostoker coherent-potential approximation) computations of these directional profiles. The Fermi surface determined by inverting the Compton data is found to be in good agreement with the KKR-CPA predictions. An electron diffraction study of the present Cu0.842Al0.158 sample is additionally undertaken to gain insight into short-range ordering effects. The scattering pattern displays not only the familiar diffuse scattering peaks, but also shows the presence of weak streaks interconnecting the four diffuse scattering spots around the (110) reciprocal lattice points. This study provides a comprehensive picture of the evolution of the shape of the Fermi surface of Cu with the addition of Al . Our results are consistent with the notion that Fermi surface nesting is an important factor in driving short-range ordering effects in disordered alloys.

Longitudinal Target-Spin Asymmetries for Deeply Virtual Compton Scattering

Science.gov (United States)

Seder, E.; Biselli, A.; Pisano, S.; Niccolai, S.; Smith, G. D.; Joo, K.; Adhikari, K.; Amaryan, M. J.; Anderson, M. D.; Anefalos Pereira, S.; Avakian, H.; Battaglieri, M.; Bedlinskiy, I.; Bono, J.; Boiarinov, S.; Bosted, P.; Briscoe, W.; Brock, J.; Brooks, W. K.; Bültmann, S.; Burkert, V. D.; Carman, D. S.; Carlin, C.; Celentano, A.; Chandavar, S.; Charles, G.; Colaneri, L.; Cole, P. L.; Contalbrigo, M.; Crabb, D.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Doughty, D.; Dupre, R.; El Fassi, L.; Elouadrhiri, L.; Eugenio, P.; Fedotov, G.; Fegan, S.; Filippi, A.; Fleming, J. A.; Fradi, A.; Garillon, B.; Garçon, M.; Gevorgyan, N.; Ghandilyan, Y.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Gohn, W.; Gothe, R. W.; Griffioen, K. A.; Guegan, B.; Guidal, M.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Harrison, N.; Hattawy, M.; Hirlinger Saylor, N.; Holtrop, M.; Hughes, S. M.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jo, H. S.; Joosten, S.; Keith, C. D.; Keller, D.; Khachatryan, G.; Khandaker, M.; Kim, A.; Kim, W.; Klein, A.; Klein, F. J.; Koirala, S.; Kubarovsky, V.; Kuhn, S. E.; Lenisa, P.; Livingston, K.; Lu, H. Y.; MacGregor, I. J. D.; Markov, N.; Mayer, M.; McKinnon, B.; Meekins, D. G.; Mineeva, T.; Mirazita, M.; Mokeev, V.; Montgomery, R.; Moody, C. I.; Moutarde, H.; Movsisyan, A.; Munoz Camacho, C.; Nadel-Turonski, P.; Niculescu, I.; Osipenko, M.; Ostrovidov, A. I.; Paolone, M.; Pappalardo, L. L.; Park, K.; Park, S.; Pasyuk, E.; Peng, P.; Phelps, W.; Pogorelko, O.; Price, J. W.; 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.; Senderovich, I.; Simonyan, A.; Skorodumina, I.; Sokhan, D.; Sparveris, N.; Stepanyan, S.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Sytnik, V.; Taiuti, M.; Tang, W.; Tian, Y.; Ungaro, M.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Watts, D. P.; Wei, X.; Weinstein, L. B.; Wood, M. H.; Zachariou, N.; Zana, L.; Zhang, J.; Zonta, I.; CLAS Collaboration

2015-01-01

A measurement of the electroproduction of photons off protons in the deeply inelastic regime was performed at Jefferson Lab using a nearly 6 GeV electron beam, a longitudinally polarized proton target, and the CEBAF Large Acceptance Spectrometer. Target-spin asymmetries for e p →e'p'γ events, which arise from the interference of the deeply virtual Compton scattering and the Bethe-Heitler processes, were extracted over the widest kinematics in Q2 , xB, t , and ϕ , for 166 four-dimensional bins. In the framework of generalized parton distributions, at leading twist the t dependence of these asymmetries provides insight into the spatial distribution of the axial charge of the proton, which appears to be concentrated in its center. These results also bring important and necessary constraints for the existing parametrizations of chiral-even generalized parton distributions.

From neutron Compton profiles to momentum distribution: Assessment of direct numerical determination

International Nuclear Information System (INIS)

Senesi, R.; Flammini, D.; Romanelli, G.; Andreani, C.

2013-01-01

Inelastic neutron scattering at high momentum transfers, in the neutron Compton scattering regime, provides an access to the neutron Compton profiles, the analogous of Compton profiles in X-ray scattering. The line shape analysis of the neutron Compton profiles is usually carried out making use of multiparametric nonlinear fitting, garnering detailed information about the momentum distribution of the target atoms. This paper presents the proposal to directly determine numerically the momentum distribution from the profiles, thus eliminating the possible instabilities present in multiparametric fitting. A comparison with Monte Carlo simulations and with previous measurements on polycrystalline ice provides quantitative assessments of the proposed method

Forward-scattered radiation from the compression paddle should be considered in glandular dose estimations

International Nuclear Information System (INIS)

Hemdal, B.

2011-01-01

From major protocols on dosimetry in mammography, there is no doubt that the incident air kerma should be evaluated without backscattered radiation to the dosemeter. However, forward-scattered radiation from the compression paddle is neglected. The aim of this work was to analyse the contribution of forward-scattered radiation for typical air kerma measurements. Measurements of forward-scatter were performed with a plane-parallel ionisation chamber on four mammography units. The forward-scatter contribution to the air kerma was 2-10 % and increased with the compression paddle thickness, but also with the half-value layer value. For incident air kerma in mammography, it can be as important to consider forward scattered as backscattered radiation. If an ionisation chamber is used, the compression paddle should be in contact with the chamber; otherwise the air kerma and absorbed dose will be underestimated. If a dosemeter based on semiconductors with much less sensitivity to scattered radiation is used, it is suggested that a forward-scatter factor (FSF) is applied. Based on the results of this work, FSF=1.06 will lead to a maximum error of ∼4 %. (authors)

Compton radiography, 1

International Nuclear Information System (INIS)

Okuyama, Shinichi; Sera, Koichiro; Fukuda, Hiroshi; Shishido, Fumio; Matsuzawa, Taiju

1977-01-01

Tomographic images of an object are obtainable by irradiating it with a collimated beam of monochromatic gamma rays and recording the resultant Compton rays scattered upward at right angles. This is the scattered-ray principle of the formation of a radiation image that differs from the traditional ''silhouette principle'' of radiography, and that bears prospects of stereopsis as well as cross-section tomography. (Evans, J.)

The Compton polarimeter at ELSA

International Nuclear Information System (INIS)

Doll, D.

1998-06-01

In order to measure the degree of transverse polarization of the stored electron beam in the Electron Stretcher Accelerator ELSA a compton polarimeter is built up. The measurement is based on the polarization dependent cross section for the compton scattering of circular polarized photons off polarized electrons. Using a high power laser beam and detecting the scattered photons a measuring time of two minutes with a statistical error of 5% is expected from numerical simulations. The design and the results of a computer controlled feedback system to enhance the laser beam stability at the interaction point in ELSA are presented. The detection of the scattered photons is based on a lead converter and a silicon-microstrip detector. The design and test results of the detector module including readout electronic and computer control are discussed. (orig.)

Time evolution analysis of the electron distribution in Thomson/Compton back-scattering

International Nuclear Information System (INIS)

Petrillo, V.; Bacci, A.; Curatolo, C.; Maroli, C.; Serafini, L.; Rossi, A. R.

2013-01-01

We present the time evolution of the energy distribution of a relativistic electron beam after the Compton back-scattering with a counter-propagating laser field, performed in the framework of the Quantum Electrodynamics, by means of the code CAIN. As the correct angular distribution of the spontaneous emission is accounted, the main effect is the formation of few stripes, followed by the diffusion of the more energetic particles toward lower values in the longitudinal phase space. The Chapman-Kolmogorov master equation gives results in striking agreement with the numerical ones. An experiment on the Thomson source at SPARC-LAB is proposed

Doppler broadening and its contribution to Compton energy-absorption cross sections: An analysis of the Compton component in terms of mass-energy absorption coefficient

International Nuclear Information System (INIS)

Rao, D.V.; Takeda, T.; Itai, Y.; Akatsuka, T.; Cesareo, R.; Brunetti, A.; Gigante, G.E.

2002-01-01

Compton energy absorption cross sections are calculated using the formulas based on a relativistic impulse approximation to assess the contribution of Doppler broadening and to examine the Compton profile literature and explore what, if any, effect our knowledge of this line broadening has on the Compton component in terms of mass-energy absorption coefficient. Compton energy-absorption cross sections are evaluated for all elements, Z=1-100, and for photon energies 1 keV-100 MeV. Using these cross sections, the Compton component of the mass-energy absorption coefficient is derived in the energy region from 1 keV to 1 MeV for all the elements Z=1-100. The electron momentum prior to the scattering event should cause a Doppler broadening of the Compton line. The momentum resolution function is evaluated in terms of incident and scattered photon energy and scattering angle. The overall momentum resolution of each contribution is estimated for x-ray and γ-ray energies of experimental interest in the angular region 1 deg. -180 deg. . Also estimated is the Compton broadening using nonrelativistic formula in the angular region 1 deg. -180 deg., for 17.44, 22.1, 58.83, and 60 keV photons for a few elements (H, C, N, O, P, S, K, and Ca) of biological importance

Doppler Broadening and its Contribution to Compton Energy-Absorption Cross Sections: An Analysis of the Compton Component in Terms of Mass-Energy Absorption Coefficient

Science.gov (United States)

Rao, D. V.; Takeda, T.; Itai, Y.; Akatsuka, T.; Cesareo, R.; Brunetti, A.; Gigante, G. E.

2002-09-01

Compton energy absorption cross sections are calculated using the formulas based on a relativistic impulse approximation to assess the contribution of Doppler broadening and to examine the Compton profile literature and explore what, if any, effect our knowledge of this line broadening has on the Compton component in terms of mass-energy absorption coefficient. Compton energy-absorption cross sections are evaluated for all elements, Z=1-100, and for photon energies 1 keV-100 MeV. Using these cross sections, the Compton component of the mass-energy absorption coefficient is derived in the energy region from 1 keV to 1 MeV for all the elements Z=1-100. The electron momentum prior to the scattering event should cause a Doppler broadening of the Compton line. The momentum resolution function is evaluated in terms of incident and scattered photon energy and scattering angle. The overall momentum resolution of each contribution is estimated for x-ray and γ-ray energies of experimental interest in the angular region 1°-180°. Also estimated is the Compton broadening using nonrelativistic formula in the angular region 1°-180°, for 17.44, 22.1, 58.83, and 60 keV photons for a few elements (H, C, N, O, P, S, K, and Ca) of biological importance.

Analysis on Target Detection and Classification in LTE Based Passive Forward Scattering Radar

OpenAIRE

Raja Syamsul Azmir Raja Abdullah; Noor Hafizah Abdul Aziz; Nur Emileen Abdul Rashid; Asem Ahmad Salah; Fazirulhisyam Hashim

2016-01-01

The passive bistatic radar (PBR) system can utilize the illuminator of opportunity to enhance radar capability. By utilizing the forward scattering technique and procedure into the specific mode of PBR can provide an improvement in target detection and classification. The system is known as passive Forward Scattering Radar (FSR). The passive FSR system can exploit the peculiar advantage of the enhancement in forward scatter radar cross section (FSRCS) for target detection. Thus, the aim of th...

Commissioning of the scatter component of a Compton camera consisting of a stack of Si strip detectors

Energy Technology Data Exchange (ETDEWEB)

Liprandi, S.; Marinsek, T.; Bortfeldt, J.; Lang, C.; Lutter, R.; Dedes, G.; Parodi, K.; Thirolf, P.G. [LMU Munich, Garching (Germany); Aldawood, S. [LMU Munich, Garching (Germany); King Saud University, Riyadh (Saudi Arabia); Maier, L.; Gernhaeuser, R. [TU Munich, Garching (Germany); Kolff, H. van der [LMU Munich, Garching (Germany); TU Delft (Netherlands); Castelhano, I. [LMU Munich, Garching (Germany); University of Lisbon, Lisbon (Portugal); Schaart, D.R. [TU Delft (Netherlands)

2015-07-01

At LMU Munich in Garching a Compton camera is presently being developed aiming at the range verification of proton (or ion) beams for hadron therapy via imaging of prompt γ rays from nuclear reactions in the tissue. The poster presentation focuses on the characterization of the scatter component of the Compton camera, consisting of a stack of six double-sided Si strip detectors (50 x 50 mm{sup 2}, 0.5 mm thick, 128 strips/side). The overall 1536 electronics channels are processed by a readout system based on the GASSIPLEX ASIC chip, feeding into a VME-based data acquisition system. The status of the offline and online characterization studies is presented.

Laser propagation and compton scattering in parabolic plasma channel

CERN Document Server

Dongguo, L; Yokoya, K; Hirose, T

2003-01-01

A Gaussian laser beam propagating in a parabolic plasma channel is discussed in this paper. For a weak laser, plasma density perturbation induced by interaction between the laser field and plasma is very small, the refractive index can be assumed to be constant with respect to time variable. For a parabolic plasma channel, through the static propagation equation, we obtain an analytical solution of the profile function of the Gaussian laser beam for an unmatched case and give the general condition for the matched case. As the laser intensity increases, an effect due to strong laser fields is included. We discuss how to design and select the distribution of plasma density for a certain experiment in which a plasma channel is utilized to guide a laser beam. The number of scattered photons (X-rays) generated through Compton backscattering in a plasma channel is discussed. (author)

Laser-Compton Scattering as a Potential Electron Beam Monitor

International Nuclear Information System (INIS)

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

2002-01-01

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

Experimental determination of absolute-scale compton cross sections using the K X-ray escape and a comparison with three versions of the impulse approximation

International Nuclear Information System (INIS)

Pasic, S.; Uroic, M.; Tocilj, Z.; Majer, M.; Gamulin, O.; Bokulic, T.; Ilakovac, K.

2005-01-01

Double-differential Compton cross sections at two incident photon energies of 68.9 and 70.8 keV (mercury Kα X-rays) at the scattering angle of about 172 deg were measured in germanium using the coincidence technique with a detector as the scatterer. The cross sections were determined by normalization of the Compton spectra to the peaks due to the escape of characteristic Kα and Kβ X-rays from the target detector. This new approach of determination of absolute-scale Compton cross sections can also be applied in widely used single-mode measurements (source-scatterer-detector assembly). Our analysis shows that the new method is especially convenient and accurate at lower incident photon energies above the K-edge in the target atoms. The experimental results are compared with the non-relativistic impulse approximation, the frequently used simplified version of the relativistic impulse approximation and the non-relativistic impulse approximation used with the relativistic expression for the atomic electron momentum in the direction of the photon momentum transfer. Contrary to our expectation, the non-relativistic impulse approximation clearly gives the best agreement with the experimental data in the region of the Compton peak

Nucleon polarizabilities from deuteron Compton scattering within a Green's function hybrid approach

Energy Technology Data Exchange (ETDEWEB)

Hildebrandt, R.P.; Hemmert, T.R. [Technische Universitaet Muenchen, Institut fuer Theoretische Physik (T39), Physik-Department, Garching (Germany); Griesshammer, H.W. [Technische Universitaet Muenchen, Institut fuer Theoretische Physik (T39), Physik-Department, Garching (Germany); Universitaet Erlangen-Nuernberg, Institut fuer Theoretische Physik III, Naturwissenschaftliche Fakultaet I, Erlangen (Germany); The George Washington University, Center for Nuclear Studies, Department of Physics, Washington DC (United States)

2010-10-15

We examine elastic Compton scattering from the deuteron for photon energies ranging from zero to 100MeV, using state-of-the-art deuteron wave functions and NN potentials. Nucleon-nucleon rescattering between emission and absorption of the two photons is treated by Green's functions in order to ensure gauge invariance and the correct Thomson limit. With this Green's function hybrid approach, we fulfill the low-energy theorem of deuteron Compton scattering and there is no significant dependence on the deuteron wave function used. Concerning the nucleon structure, we use the chiral effective field theory with explicit {delta} (1232) degrees of freedom within the small-scale expansion up to leading-one-loop order. Agreement with available data is good at all energies. Our 2-parameter fit to all elastic {gamma} d data leads to values for the static isoscalar dipole polarizabilities which are in excellent agreement with the isoscalar Baldin sum rule. Taking this value as additional input, we find {alpha}{sub E}{sup s} = (11.3{+-}0.7(stat){+-}0.6(Baldin){+-}1(theory)){sup .}10{sup -4} fm{sup 3} and {beta}{sub M}{sup s} = (3.2{+-}0.7(stat){+-}0.6(Baldin){+-}1(theory)){sup .}10{sup -4} fm{sup 3} and conclude by comparison to the proton numbers that neutron and proton polarizabilities are the same within rather small errors. (orig.)

High Precision Measurement of the Neutron Polarizabilities via Compton Scattering on Deuterium at Eγ=65 MeV

Science.gov (United States)

Sikora, Mark; Compton@HIGS Team

2017-01-01

The electric (αn) and magnetic (βn) polarizabilities of the neutron are fundamental properties arising from its internal structure which describe the nucleon's response to applied electromagnetic fields. Precise measurements of the polarizabilities provide crucial constraints on models of Quantum Chromodynamics (QCD) in the low energy regime such as Chiral Effective Field Theories as well as emerging ab initio calculations from lattice-QCD. These values also contribute the most uncertainty to theoretical determinations of the proton-neutron mass difference. Historically, the experimental challenges to measuring αn and βn have been due to the difficulty in obtaining suitable targets and sufficiently intense beams, leading to significant statistical uncertainties. To address these issues, a program of Compton scattering experiments on the deuteron is underway at the High Intensity Gamma Source (HI γS) at Duke University with the aim of providing the world's most precise measurement of αn and βn. We report measurements of the Compton scattering differential cross section obtained at an incident photon energy of 65 MeV and discuss the sensitivity of these data to the polarizabilities.

The use of Compton scattering to differentiate between classifications of normal and diseased breast tissue

Energy Technology Data Exchange (ETDEWEB)

Ryan, Elaine A; Farquharson, Michael J; Flinton, David M [School of Allied Health Sciences, City University, Charterhouse Square, London EC1M 6PA (United Kingdom)

2005-07-21

This study describes a technique for measuring the electron density of breast tissue utilizing Compton scattered photons. The K{sub {alpha}}{sub 2} line from a tungsten target industrial x-ray tube (57.97 keV) was used and the scattered x-rays collected at an angle of 30{sup 0}. At this angle the Compton and coherent photon peaks can be resolved using an energy dispersive detector and a peak fitting algorithm. The system was calibrated using solutions of known electron density. The results obtained from a pilot study of 22 tissues are presented. The tissue samples investigated comprise four different tissue classifications: adipose, malignancy, fibroadenoma and fibrocystic change (FCC). It is shown that there is a difference between adipose and malignant tissue, to a value of 9.0%, and between adipose and FCC, to a value of 12.7%. These figures are found to be significant by statistical analysis. The differences between adipose and fibroadenoma tissues (2.2%) and between malignancy and FCC (3.4%) are not significant. It is hypothesized that the alteration in glucose uptake within malignant cells may cause these tissues to have an elevated electron density. The fibrotic nature of tissue that has undergone FCC gives the highest measure of all tissue types.

The use of Compton scattering to differentiate between classifications of normal and diseased breast tissue

Science.gov (United States)

Ryan, Elaine A.; Farquharson, Michael J.; Flinton, David M.

2005-07-01

This study describes a technique for measuring the electron density of breast tissue utilizing Compton scattered photons. The Kα2 line from a tungsten target industrial x-ray tube (57.97 keV) was used and the scattered x-rays collected at an angle of 30°. At this angle the Compton and coherent photon peaks can be resolved using an energy dispersive detector and a peak fitting algorithm. The system was calibrated using solutions of known electron density. The results obtained from a pilot study of 22 tissues are presented. The tissue samples investigated comprise four different tissue classifications: adipose, malignancy, fibroadenoma and fibrocystic change (FCC). It is shown that there is a difference between adipose and malignant tissue, to a value of 9.0%, and between adipose and FCC, to a value of 12.7%. These figures are found to be significant by statistical analysis. The differences between adipose and fibroadenoma tissues (2.2%) and between malignancy and FCC (3.4%) are not significant. It is hypothesized that the alteration in glucose uptake within malignant cells may cause these tissues to have an elevated electron density. The fibrotic nature of tissue that has undergone FCC gives the highest measure of all tissue types.

The use of Compton scattering to differentiate between classifications of normal and diseased breast tissue

International Nuclear Information System (INIS)

Ryan, Elaine A; Farquharson, Michael J; Flinton, David M

2005-01-01

This study describes a technique for measuring the electron density of breast tissue utilizing Compton scattered photons. The K α2 line from a tungsten target industrial x-ray tube (57.97 keV) was used and the scattered x-rays collected at an angle of 30 0 . At this angle the Compton and coherent photon peaks can be resolved using an energy dispersive detector and a peak fitting algorithm. The system was calibrated using solutions of known electron density. The results obtained from a pilot study of 22 tissues are presented. The tissue samples investigated comprise four different tissue classifications: adipose, malignancy, fibroadenoma and fibrocystic change (FCC). It is shown that there is a difference between adipose and malignant tissue, to a value of 9.0%, and between adipose and FCC, to a value of 12.7%. These figures are found to be significant by statistical analysis. The differences between adipose and fibroadenoma tissues (2.2%) and between malignancy and FCC (3.4%) are not significant. It is hypothesized that the alteration in glucose uptake within malignant cells may cause these tissues to have an elevated electron density. The fibrotic nature of tissue that has undergone FCC gives the highest measure of all tissue types

High Precision Measurement of the Neutron Polarizabilities via Compton Scattering on Deuterium at HI γS

Science.gov (United States)

Sikora, Mark

2016-09-01

The electric (αn) and magnetic (βn) polarizabilities of the neutron are fundamental properties arising from its internal structure which describe the nucleon's response to applied electromagnetic fields. Precise measurements of the polarizabilities provide crucial constraints on models of Quantum Chromodynamics (QCD) in the low energy regime such as Chiral Effective Field Theories as well as emerging ab initio calculations from lattice-QCD. These values also contribute the most uncertainty to theoretical determinations of the proton-neutron mass difference. Historically, the experimental challenges to measuring αn and βn have been due to the difficulty in obtaining suitable targets and sufficiently intense beams, leading to significant statistical uncertainties. To address these issues, a program of Compton scattering experiments on the deuteron is underway at the High Intensity Gamma Source (HI γS) at Duke University with the aim of providing the world's most precise measurement of αn and βn. We report measurements of the Compton scattering differential cross section obtained at incident photon energies of 65 and 85 MeV and discuss the sensitivity of these data to the polarizabilities.

System automation for a bacterial colony detection and identification instrument via forward scattering

International Nuclear Information System (INIS)

Bae, Euiwon; Hirleman, E Daniel; Aroonnual, Amornrat; Bhunia, Arun K; Robinson, J Paul

2009-01-01

A system design and automation of a microbiological instrument that locates bacterial colonies and captures the forward-scattering signatures are presented. The proposed instrument integrates three major components: a colony locator, a forward scatterometer and a motion controller. The colony locator utilizes an off-axis light source to illuminate a Petri dish and an IEEE1394 camera to capture the diffusively scattered light to provide the number of bacterial colonies and two-dimensional coordinate information of the bacterial colonies with the help of a segmentation algorithm with region-growing. Then the Petri dish is automatically aligned with the respective centroid coordinate with a trajectory optimization method, such as the Traveling Salesman Algorithm. The forward scatterometer automatically computes the scattered laser beam from a monochromatic image sensor via quadrant intensity balancing and quantitatively determines the centeredness of the forward-scattering pattern. The final scattering signatures are stored to be analyzed to provide rapid identification and classification of the bacterial samples

Determination of integral K-shell Compton scattering cross-sections in elements 41>=Z>=51 for 1250 keV photons

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.

Optimal sum-rule inequalities for spin 1/2 Compton scattering. III

International Nuclear Information System (INIS)

Filkov, L.V.

1980-10-01

The analyticity (optimal) bounds for proton Compton scattering presented in the preceding paper are herewith considered from the point of view of experimental tests. An essential function occuring in this new dispersion framework is constructed numerically making use of existing cross-section data above the pion photoproduction threshold. To secure a safer construction new measurements in the photon laboratory energy region 150 MeV - 240 MeV and at small momentum transfers are necessary. The bounds on the scattering amplitudes in the low energy region below the pion photoproduction threshold are in general sufficiently restrictive so as to be useful in discriminating among variants of theoretical phenomenological analyses but subsequent extremizations needed in bounding only one combination of the amplitudes (the unpolarized differential cross-section) are weakening much the results. The question of strengthening the bounds by means of the combined use of analyticity and unitarity is discussed within a very crude example which nonetheless illustrates that the inclusion of the pion photoproduction data through more elaborate mathematical procedures would deserve the effort. (author)

Forward elastic scattering of electrons by hydrogen atoms

Energy Technology Data Exchange (ETDEWEB)

Garibotti, C.R. (Instituto de Fisica Teorica, R. Pamplona 145, Sao Paulo (Brazil)); Massaro, P.A. (Bari Univ. (Italy). Ist. di Fisica)

1978-01-11

The available theoretical and experimental values for the elastic, inelastic and ionization cross-sections of electrons by hydrogen atoms are used to obtain the total cross-section. The optical theorem and a dispersion relation are used to calculate the forward e-H scattering amplitude for medium and high energies. Using this quantity the reliability of the Born expansion for elastic e-H scattering is tested.

Study of Compton scattering influence in cardiac SPECT images

International Nuclear Information System (INIS)

Munhoz, A.C.L.; Abe, R.; Zanardo, E.L.; Robilotta, C.C.

1992-01-01

The reduction effect from Compton fraction in the quality of and image is evaluated, with two ways of acquisition data: one, with the window of energetic analyser dislocated over the photopeak and the other, with two windows, one over the Compton contribution and the other, placed in the center over the photopeak. (C.G.C.)

Wide angle Compton scattering within the SCET factorization framework

International Nuclear Information System (INIS)

Kivel, N.

2016-01-01

Existing data for the electromagnetic proton form factors and for the cross section of the wide angle Compton scattering (WACS) show that the hard two-gluon exchange mechanism (collinear factorization) is still not applicable in the kinematical region where Mandelstam variables s ∼ -t ∼ -u are about a few GeV 2 . On the other hand these observables can be described in phenomenological models where spectator quarks are soft which assumes a large contribution due to the soft-overlap mechanism. It turns out that the simple QCD factorization picture is not complete and must also include the soft-overlap contribution which can be described as a certain matrix element in the soft collinear effective theory (SCET). Then the leading power contribution to WACS amplitude is described as a sum of the hard- and soft-spectator contributions. The existing experimental data allows one to check certain conclusions based on the assumption about dominant role of the soft-spectator mechanism. (author)

Geometrical-optics approximation of forward scattering by gradient-index spheres.

Science.gov (United States)

Li, Xiangzhen; Han, Xiang'e; Li, Renxian; Jiang, Huifen

2007-08-01

By means of geometrical optics we present an approximation method for acceleration of the computation of the scattering intensity distribution within a forward angular range (0-60 degrees ) for gradient-index spheres illuminated by a plane wave. The incident angle of reflected light is determined by the scattering angle, thus improving the approximation accuracy. The scattering angle and the optical path length are numerically integrated by a general-purpose integrator. With some special index models, the scattering angle and the optical path length can be expressed by a unique function and the calculation is faster. This method is proved effective for transparent particles with size parameters greater than 50. It fails to give good approximation results at scattering angles whose refractive rays are in the backward direction. For different index models, the geometrical-optics approximation is effective only for forward angles, typically those less than 60 degrees or when the refractive-index difference of a particle is less than a certain value.

Compton scatter tomography in TOF-PET

Science.gov (United States)

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.

Inverse compton emission of gamma rays near the pulsar surface

International Nuclear Information System (INIS)

Morini, M.

1981-01-01

The physical conditions near pulsar surface that might give rise to gamma ray emission from Crab and Vela pulsars are not yet well understood. Here I suggest that, in the context of the vacuum discharge mechanism proposed by Ruderman and Sutherland (1975), gamma rays are produced by inverse Compton scattering of secondary electrons with the thermal radiation of the star surface as well as for curvature and synchotron radiation. It is found that inverse Compton scattering is relevant if the neutron star surface temperature is greater than 10 6 K or of the polar cap temperature is of the order of 5 x 10 6 K. Inverse Compton scattering in anisotropic photon fields and Klein-Nishina regime is here carefully considered. (orig.)

Compton scattering on the proton, neutron, and deuteron in chiral perturbation theory to O(Q{sup 4})

Energy Technology Data Exchange (ETDEWEB)

S.R. Beane; M. Malheiro; J.A. McGovern; D.R. Phillips; U. van Kolck

2004-03-01

We study Compton scattering in systems with A=1 and 2 using chiral perturbation theory up to fourth order. For the proton we fit the two undetermined parameters in the O(Q{sup 4}) {gamma}p amplitude of McGovern to experimental data in the region {omega}, {radical}|t| {le} 180 MeV, obtaining a {chi}{sup 2}/d.o.f. of 133/113. This yields a model-independent extraction of proton polarizabilities based solely on low-energy data: {alpha}{sub p} = (12.1 {+-} 1.1 (stat.)){sub -0.5}{sup +0.5} (theory) and {beta}{sub p} = (3.4 {+-} 1.1 (stat.)){sub -0.1}{sup +0.1} (theory), both in units of 10{sup -4} fm{sup 3}. We also compute Compton scattering on deuterium to O(Q{sup 4}). The {gamma}d amplitude is a sum of one- and two-nucleon mechanisms, and contains two undetermined parameters, which are related to the isoscalar nucleon polarizabilities. We fit data points from three recent {gamma}d scattering experiments with a {chi}{sup 2}/d.o.f. = 26.3/20, and find {alpha}{sub N} = 8.9 {+-} 1.5 (stat.){sub -0.9}{sup +4.7} (theory) and {beta}{sub N} = 2.2 {+-} 1.5 (stat.){sub -0.9}{sup +1.2} (theory), again in units of 10{sup -4} fm{sup 3}.

The pion-deuteron forward elastic amplitude in the non-overlapping potentials model

International Nuclear Information System (INIS)

Butterworth, D.S.

1978-01-01

The pion-deuteron forward elastic amplitude has been calculated in the non-overlapping potentials model, which enables a description of off-shell propagation effects in terms of on-shell amplitudes. Calculations include spin, isospin and deuteron D-state probability effects. Two energy regions are considered. First the pion-nucleon P 33 resonance region, where, using a formalism developed by Agassi and Gal (Ann. Phys.; 75:56 (1973) and 94:184 (1975)), the full multiple-scattering series is summed in an approximation of P 33 wave dominance of the higher-order scatterings. Second, for the subsequent highest-energy region, the double-scattering term only is calculated. Fermi smearing effects are included in both cases. Predictions for the total cross section, its dependence on the deuteron alignment and the real part of the forward elastic amplitude are compared with those of Glauber theory, and data where available. Convergence of the multiple-scattering series is also discussed. (author)

Feasibility of Strong and Quasi-Monochromatic Gamma-Ray Generation by the Laser Compton Scattering

Energy Technology Data Exchange (ETDEWEB)

Lee, Jiyoung; Rehman, Haseeb ur; Kim, Yonghee [KAIST, Daejeon (Korea, Republic of)

2015-10-15

This is because LCS γ-rays are energy-tunable, quasi-monochromatic, and beam-like. The photon intensity of the mono-chromatic LCS gamma-ray should be high or strong for efficient and high transmutation rate. It was recently reported that a so-called energy-recovery linac system is able to produce a very high-intensity LCS photons in the order of approximately 1013 photons/s economically. It however did not evaluate quality of the LCS photon beam although a quasi-monoenergetic LCS beam is of huge importance in the photo-nuclear transmutation reactions. It is upon this observation that this paper was prepared. Specifically, this work attempts to quantify intensity of the quasi-monochromatic LCS beam from the said linac system. In addition, this paper aims to discuss general characteristics of the LCS photon, and possible approaches to increase its intensity. This paper presents essential characteristics of the laser Compton scattering (LCS) in terms of its photon energy, cross-section and photon intensity. By using different combinations of electron energy, laser energy and scattering angle, we can effectively generate high-intensity and highly-chromatic LCS gamma-rays. Our preliminary analyses indicate that, in view of Compton cross-section, higher-energy photon can be better generated by increasing the electron energy rather than increasing the laser energy. However, in order to maximize the intensity of monochromatic beam, the laser energy should be maximized for a targeted LCS photon energy.

Analysis of forward and near-forward elastic-scattering amplitudes for pp and anti pp collisions

International Nuclear Information System (INIS)

Block, M.B.; Cahn, R.N.

1983-04-01

We will present the results of two recently published (1983) papers by M.M. Block and R.N. Cahn, which analyze for anti pp and pp elastic scattering the rho values (ratios of the real to the imaginary parts of the forward nuclear scattering amplitudes), the total (hadronic) cross sections sigma, and the b values, the nuclear slope parameters. The predictions of the analyses, from √ s bar > 5 GeV, is compared with the recently measured values of sigma and b at the SPS Collider. The analysis has also been redone to include new ISR data available from R211 at √ s bar = 62.5 GeV, in order to estimate odderon contributions, i.e., contributions from odd amplitudes with unconventional (non-Reggeon) energy dependence. Limits of approx. 1% are placed on these amplitudes. Our analysis has been extrapolated up to 100 TeV, to give sigma, rho and b predictions for cosmic ray and future collider energies

Geometrical effects determinant of the Compton profile shape

International Nuclear Information System (INIS)

Sartori, Renzo; Mainardi, R.T.

1987-01-01

The main purpose of this work is to evaluate the influence of the experimental set up on the shape of the Compton line. In any scattering experiment, the scattering angle is not well defined due to the collimators aperture and thus, a distribution of angles is found for each set up. This, in turn, produces the energies' distribution of the scattered photons around a mean value. This contribution has been evaluated and found it to be significant for several cases. In order to do this evaluation, a response function, that is numerically generated for each experimental set up and convoluted with the Compton profile, was defined. (Author) [es

The temperature dependence of the momentum distribution of beryllium measured by neutron Compton scattering

International Nuclear Information System (INIS)

Fielding, A.L.; Timms, D.; Mayers, J.

1999-01-01

A new neutron Compton scattering (NCS) measurement of the temperature dependence of the kinetic energy in polycrystalline beryllium at momentum transfers in the range 27.91 to 104.21 A -1 is presented. The measurements have been made with the Electron Volt Spectrometer (eVS) at the ISIS facility and the measured kinetic energies are shown to be in good agreement with calculations made in the harmonic approximation. Numerical simulations are also presented based on the Sears expansion which predict that final state effects in NCS experiments become less significant at elevated temperatures. (author)

Geometrical-optics approximation of forward scattering by coated particles.

Science.gov (United States)

Xu, Feng; Cai, Xiaoshu; Ren, Kuanfang

2004-03-20

By means of geometrical optics we present an approximation algorithm with which to accelerate the computation of scattering intensity distribution within a forward angular range (0 degrees-60 degrees) for coated particles illuminated by a collimated incident beam. Phases of emerging rays are exactly calculated to improve the approximation precision. This method proves effective for transparent and tiny absorbent particles with size parameters larger than 75 but fails to give good approximation results at scattering angles at which refractive rays are absent. When the absorption coefficient of a particle is greater than 0.01, the geometrical optics approximation is effective only for forward small angles, typically less than 10 degrees or so.

A high-energy Compton polarimeter for the POET SMEX mission

Science.gov (United States)

Bloser, Peter F.; McConnell, Mark L.; Legere, Jason S.; Ertley, Camden D.; Hill, Joanne E.; Kippen, Marc; Ryan, James M.

2014-07-01

The primary science goal of the Polarimeters for Energetic Transients (POET) mission is to measure the polarization of gamma-ray bursts over a wide energy range, from X rays to soft gamma rays. The higher-energy portion of this band (50 - 500 keV) will be covered by the High Energy Polarimeter (HEP) instrument, a non-imaging, wide field of view Compton polarimeter. Incident high-energy photons will Compton scatter in low-Z, plastic scintillator detector elements and be subsequently absorbed in high-Z, CsI(Tl) scintillator elements; polarization is detected by measuring an asymmetry in the azimuthal scatter angle distribution. The HEP design is based on our considerable experience with the development and flight of the Gamma-Ray Polarimeter Experiment (GRAPE) balloon payload. We present the design of the POET HEP instrument, which incorporates lessons learned from the GRAPE balloon design and previous work on Explorer proposal efforts, and its expected performance on a two-year SMEX mission.

Compton Scattering from the Deuteron at Low Energies

International Nuclear Information System (INIS)

Lundin, Magnus

2002-05-01

A series of three Compton scattering experiments on deuterium have been performed at the high-resolution tagged-photon facility MAX-lab located in Lund, Sweden. The 50 g x 10 ) NaI detectors. The average laboratory angles investigated were 45, 125 and 135 deg. The influence of the inelastic contribution was minimized by implementing a narrow elastic fit-region in the missing energy spectra. Absolute cross sections were extracted for average photon energies of 55 and 66 MeV at each angle and for each experiment. The extracted cross sections are in good agreement with those measured at Illinois by Lucas et al. The difference between the electric and magnetic isospin-averaged polarizabilities of the nucleon inside the deuteron, was varied within the calculations of Levchuk and L'vov to best reproduce the data, holding the sum fixed at 14.6 (10 -4 fm 3 ). The result implies that the electric polarizability of the neutron is the same as that of the proton within the experimental uncertainties. The result also indicates that the magnetic polarizability of the neutron is larger than that of the proton

The dispersion relation for the forward elastic electron-atom scattering amplitude

International Nuclear Information System (INIS)

Amusia, M.Y.

1978-01-01

The analytical properties of forward elastic electron-atom scattering amplitude are discussed. It is noted that the occurrence of exchange between the incoming and atomic electrons leads to the appearance of a number of singularities on the negative real axis in the complex energy plane. The conclusion is drawn that the dispersion relation for the forward electron-atom scattering amplitude should also include an integration over the negative energy from - I to - infinity, where I is the ionization potential. (author)

Theoretical evaluation of the Doppler broadening contribution to the angular resolution in CdZnTe Compton scattering detector

International Nuclear Information System (INIS)

Diaz Garcia, A.; Cabal Rodriguez, A.E.; Rubio Rodriguez, J. A.; Salicio Diez, J.; Perez Morales, J.M.; Vela Morales, O.; Willmott Zappacosta, C.; Van Espen, P.

2011-01-01

Electronically collimated Compton Cameras have been tested in Single Photon Emission Tomography (SPECT) systems instead of mechanically collimated gamma detectors in order to improve their limited sensitivity. One of the main factors that contribute to the worsening of the angular resolution and thus to the deterioration of the system spatial resolution is Doppler broadening. Double differential Klein-Nishina equation is used to consider the random movement of electron inside the crystal. It is important to perform this analysis for each particular material because is difficult to infer one simple Doppler broadening dependency of the atomic number Z. In high Z materials the internal electrons are strongly linked to the nucleus and therefore there can be found high momentums, but they represent just a small portion of the electrons that suffers Compton scattering. This work estimates the influence of the Doppler broadening in CdZnTe semiconductor for different incoming photon energies. For this means there are analyzed main Compton broadening processes in semiconductor Cd 0,8 Zn 0,2 Te with density ρ=5,85g/cm 3 . (Author)

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)

Investigation of lithium forward scattering for the analysis of carbon and oxygen in human amniotic fluid

International Nuclear Information System (INIS)

Liendo, J.A.; Instituto Venezolano de Investigaciones Cientificas, Caracas; Florida State University, Tallahasse, FL; Gonzalez, A.C.; Rojas, A.; Instituto Venezolano de Investigaciones Cientificas, Caracas; Fletcher, N.R.; Caussyn, D.D.; Barber, P.

2006-01-01

Lithium forward elastic scattering is investigated as an additional method for Z 6,7 Li beams and the elastically scattered beam is detected at 16.45 deg, 20.45 deg and 28.0 deg simultaneously. The quality of elastic spectra improves with sample dilution. The content of C and O in the backing is subtracted. Carbon and oxygen concentrations of the non-diluted AF sample are determined by assuming that elemental concentration varies linearly with dilution. (author)

Magnetic Compton scattering study of Laves phase ZrFe2 and Sc doped ZrFe2: Experiment and Green function based relativistic calculations

Science.gov (United States)

Bhatt, Samir; Mund, H. S.; Kumar, Kishor; Bapna, Komal; Dashora, Alpa; Itou, M.; Sakurai, Y.; Ahuja, B. L.

2018-05-01

Spin momentum densities of ferromagnetic ZrFe2 and Zr0.8Sc0.2Fe2 have been measured using magnetic Compton scattering with 182.65 keV circularly polarized synchrotron radiations. Site specific spin moments, which are responsible for the formation of total spin moment, have been deduced from Compton line shapes. At room temperature, the computed spin moment of ZrFe2 is found to be slightly higher than that of Sc doped ZrFe2 which is in consensus with the magnetization data. To compare the experimental data, we have also computed magnetic Compton profiles (MCPs), total and partial spin projected density of states (DOS) and the site specific spin moments using spin-polarized relativistic Korringa-Kohn-Rostoker method. It is observed that the spin moment at Fe site is aligned antiparallel to that of Zr site in both ZrFe2 and Zr0.8Sc0.2Fe2. The MCP results when compared with vibrating sample magnetometer based magnetization data, show a very small contribution of orbital moment in the formation of total magnetic moments in both the compounds. The DOS of ferromagnetic ground state of ZrFe2 and Zr0.8Sc0.2Fe2 are interpreted on the basis of a covalent magnetic model beyond the Stoner rigid band model. It appears that on alloying between a magnetic and a non-magnetic partner (with low valence), a polarization develops on the non-magnetic atom which is anti-parallel to that of the magnetic atom.

Large-angle coherent/Compton scattering method for measurement in vitro of trabecular bone mineral concentration

International Nuclear Information System (INIS)

Gigante, G.E.; Sciuti, S.

1985-01-01

In this paper, experiments and related theoretical deductions on coherent/Compton scattering of 59.5-keV Am241 gamma line by bonelike materials are described. In particular, the authors demonstrate that a photon scattering mineralometer (PSM) can attain the best working conditions when it operates in a backscattering geometry mode. In fact, the large scattering angle they chose, theta = 135 degrees, allowed them to assemble a very compact source-detector device. Further, the relative sensitivity at 135 degrees turns out to be congruent to 1.7 and congruent to 6 times bigger than at 90 degrees and 45 degrees, respectively. The performances of the theta = 135 degrees PSM were experimentally investigated; i.e., in a measuring time of 10(3) s, a congruent to 5% statistical precision for bonelike materials, such as K 2 HPO 4 -water solutions, was obtained. The large-angle PSM device seems to be very promising for trabecular bone mineral density measurements in vivo in peripheral anatomic sites

Electric and magnetic polarizabilities of hadrons via elastic Compton scattering at KAON

International Nuclear Information System (INIS)

Moinester, M.A.; Blecher, M.

1990-08-01

The study of dynamic properties of hadrons presents a challenge. Among the most basic of these are the electric and magnetic polarizabilities describing the electromagnetic structure of hadrons. They characterize the induced transient dipole moments of hadrons in an external electromagnetic field. During gamma-hadron Compton scattering the lowest order scattering is determined by the charge and magnetic moment. The next order scattering is determined by the induced dipole moments. The dipole polarizabilities probe the rigidity of the internal structure of baryons and mesons, the dipole moments being induced by the rearrangement of the hadron constituents driven by the presence of the electric and magnetic fields of the photon during scattering. A sophisticated understanding of hadrons within the framework of QCD will be tested, in part, by the prediction of these quantities. For the light charged pion, chiral symmetry leads to a precise prediction for the polarizabilities. For the heavier charged kaon, chiral perturbation theory can be applied to predict the polarizabilities. For these cases, the experimental polarizabilities subject the underlying chiral symmetry and chiral perturbation techniques of QCD to new and serious tests. Here the physics of electromagnetic polarizabilities is first described, followed by a review of previous experimental and theoretical polarizability results for the proton, neutron, pion, and kaon. A brief description is then given of how polarizabilities for these hadrons can be studied at the proposed TRIUMF KAON facility. (36 refs., 4 figs.)

SPECT quantification: a review of the different correction methods with compton scatter, attenuation and spatial deterioration effects

International Nuclear Information System (INIS)

Groiselle, C.; Rocchisani, J.M.; Moretti, J.L.; Dreuille, O. de; Gaillard, J.F.; Bendriem, B.

1997-01-01

SPECT quantification: a review of the different correction methods with Compton scatter attenuation and spatial deterioration effects. The improvement of gamma-cameras, acquisition and reconstruction software opens new perspectives in term of image quantification in nuclear medicine. In order to meet the challenge, numerous works have been undertaken in recent years to correct for the different physical phenomena that prevent an exact estimation of the radioactivity distribution. The main phenomena that have to betaken into account are scatter, attenuation and resolution. In this work, authors present the physical basis of each issue, its consequences on quantification and the main methods proposed to correct them. (authors)

Direct observation of forward-scattering oscillations in the H+HD→H2+D reaction

Science.gov (United States)

Yuan, Daofu; Yu, Shengrui; Chen, Wentao; Sang, Jiwei; Luo, Chang; Wang, Tao; Xu, Xin; Casavecchia, Piergiorgio; Wang, Xingan; Sun, Zhigang; Zhang, Dong H.; Yang, Xueming

2018-06-01

Accurate measurements of product state-resolved angular distributions are central to fundamental studies of chemical reaction dynamics. Yet, fine quantum-mechanical structures in product angular distributions of a reactive scattering process, such as the fast oscillations in the forward-scattering direction, have never been observed experimentally and the nature of these oscillations has not been fully explored. Here we report the crossed-molecular-beam experimental observation of these fast forward-scattering oscillations in the product angular distribution of the benchmark chemical reaction, H + HD → H2 + D. Clear oscillatory structures are observed for the H2(v' = 0, j' = 1, 3) product states at a collision energy of 1.35 eV, in excellent agreement with the quantum-mechanical dynamics calculations. Our analysis reveals that the oscillatory forward-scattering components are mainly contributed by the total angular momentum J around 28. The partial waves and impact parameters responsible for the forward scatterings are also determined from these observed oscillations, providing crucial dynamics information on the transient reaction process.

HIGH-ENERGY EMISSION OF GRB 130427A: EVIDENCE FOR INVERSE COMPTON RADIATION

International Nuclear Information System (INIS)

Fan, Yi-Zhong; Zhang, Fu-Wen; He, Hao-Ning; Zhou, Bei; Yang, Rui-Zhi; Jin, Zhi-Ping; Wei, Da-Ming; Tam, P. H. T.; Liang, Yun-Feng

2013-01-01

A nearby superluminous burst GRB 130427A was simultaneously detected by six γ-ray space telescopes (Swift, the Fermi GLAST Burst Monitor (GBM)/Large Area Telescope, Konus-Wind, SPI-ACS/INTEGRAL, AGILE, and RHESSI) and by three RAPTOR full-sky persistent monitors. The isotropic γ-ray energy release is ∼10 54 erg, rendering it the most powerful explosion among gamma-ray bursts (GRBs) with a redshift z ≤ 0.5. The emission above 100 MeV lasted about one day, and four photons are at energies greater than 40 GeV. We show that the count rate of 100 MeV-100 GeV emission may be mainly accounted for by the forward shock synchrotron radiation and the inverse Compton radiation likely dominates at GeV-TeV energies. In particular, an inverse Compton radiation origin is favored for the ∼(95.3, 47.3, 41.4, 38.5, 32) GeV photons arriving at t ∼ (243, 256.3, 610.6, 3409.8, 34366.2) s after the trigger of Fermi-GBM. Interestingly, the external inverse Compton scattering of the prompt emission (the second episode, i.e., t ∼ 120-260 s) by the forward-shock-accelerated electrons is expected to produce a few γ-rays at energies above 10 GeV, while five were detected in the same time interval. A possible unified model for the prompt soft γ-ray, optical, and GeV emission of GRB 130427A, GRB 080319B, and GRB 090902B is outlined. Implications of the null detection of >1 TeV neutrinos from GRB 130427A by IceCube are discussed

Maximum Likelihood Compton Polarimetry with the Compton Spectrometer and Imager

Energy Technology Data Exchange (ETDEWEB)

Lowell, A. W.; Boggs, S. E; Chiu, C. L.; Kierans, C. A.; Sleator, C.; Tomsick, J. A.; Zoglauer, A. C. [Space Sciences Laboratory, University of California, Berkeley (United States); Chang, H.-K.; Tseng, C.-H.; Yang, C.-Y. [Institute of Astronomy, National Tsing Hua University, Taiwan (China); Jean, P.; Ballmoos, P. von [IRAP Toulouse (France); Lin, C.-H. [Institute of Physics, Academia Sinica, Taiwan (China); Amman, M. [Lawrence Berkeley National Laboratory (United States)

2017-10-20

Astrophysical polarization measurements in the soft gamma-ray band are becoming more feasible as detectors with high position and energy resolution are deployed. Previous work has shown that the minimum detectable polarization (MDP) of an ideal Compton polarimeter can be improved by ∼21% when an unbinned, maximum likelihood method (MLM) is used instead of the standard approach of fitting a sinusoid to a histogram of azimuthal scattering angles. Here we outline a procedure for implementing this maximum likelihood approach for real, nonideal polarimeters. As an example, we use the recent observation of GRB 160530A with the Compton Spectrometer and Imager. We find that the MDP for this observation is reduced by 20% when the MLM is used instead of the standard method.

Nucleon spin-averaged forward virtual Compton tensor at large Q^2

Energy Technology Data Exchange (ETDEWEB)

Hill, Richard J.; Paz, Gil

2017-05-01

The nucleon spin-averaged forward virtual Compton tensor determines important physical quantities such as electromagnetically-induced mass differences of nucleons, and two-photon exchange contributions in hydrogen spectroscopy. It depends on two kinematic variables: $\

High-temperature cuprate superconductors studied by x-ray Compton scattering and positron annihilation spectroscopies

International Nuclear Information System (INIS)

Barbiellini, Bernardo

2013-01-01

The bulk Fermi surface in an overdoped (x = 0.3) single crystal of La 2−x Sr x CuO 4 has been observed by using x-ray Compton scattering. This momentum density technique also provides a powerful tool for directly seeing what the dopant Sr atoms are doing to the electronic structure of La 2 CuO 4 . Because of wave function effects, positron annihilation spectroscopy does not yield a strong signature of the Fermi surface in extended momentum space, but it can be used to explore the role of oxygen defects in the reservoir layers for promoting high temperature superconductivity.

High-temperature cuprate superconductors studied by x-ray Compton scattering and positron annihilation spectroscopies

Science.gov (United States)

Barbiellini, Bernardo

2013-06-01

The bulk Fermi surface in an overdoped (x = 0.3) single crystal of La2-xSrxCuO4 has been observed by using x-ray Compton scattering. This momentum density technique also provides a powerful tool for directly seeing what the dopant Sr atoms are doing to the electronic structure of La2CuO4. Because of wave function effects, positron annihilation spectroscopy does not yield a strong signature of the Fermi surface in extended momentum space, but it can be used to explore the role of oxygen defects in the reservoir layers for promoting high temperature superconductivity.

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 ...

Beam dynamics simulation in the X-ray Compton source

International Nuclear Information System (INIS)

Gladkikh, P.; Karnaukhov, I.; Telegin, Yu.; Shcherbakov, A.; Zelinsky, A.

2002-01-01

At the National Science Center 'Kharkov Institute of Physics and Technology' the X-ray source based on Compton scattering has been developed. The computer code for simulation of electron beam dynamics with taking into account the Compton scattering effect based on Monte Carlo method is described in this report. The first results of computer simulation of beam dynamics with electron-photon interaction, parameters of electron and photon beams are presented. Calculations were carried out with the lattice of synchrotron light source SRS-800 Ukrainian Synchrotron Center

Beam dynamics simulation in the X-ray Compton source

CERN Document Server

Gladkikh, P; Telegin, Yu P; Shcherbakov, A; Zelinsky, A

2002-01-01

At the National Science Center 'Kharkov Institute of Physics and Technology' the X-ray source based on Compton scattering has been developed. The computer code for simulation of electron beam dynamics with taking into account the Compton scattering effect based on Monte Carlo method is described in this report. The first results of computer simulation of beam dynamics with electron-photon interaction, parameters of electron and photon beams are presented. Calculations were carried out with the lattice of synchrotron light source SRS-800 Ukrainian Synchrotron Center.

Test and performance of a BGO Compton-suppression shield for GAMMASPHERE

International Nuclear Information System (INIS)

Carpenter, M.P.; Khoo, T.L.; Ahmad, I.

1994-01-01

Bismuth germanate (BGO) compton-suppression shields have been constructed to surround the Ge detectors of the GAMMASPHERE array. A shield consists of six hexagonal tapered BGO elements, each coupled to two 1-inch x 1-inch photomultiplier tubes. In addition, a cylindrical BGO detector is placed behind the Ge detector to intercept the forward scattered gamma rays. One hundred ten such shields are planned for the GAMMASPHERE array. Procedures for measuring the performance of these shields have been developed. Large (70 %) Ge detectors when used with these shields give a peak-to-total ratio of better tan 0.60. To date more than 85 shield have been tested and approved for use in GAMMASPHERE

Partons and quarks. Daresbury lecture note series No. 12

Energy Technology Data Exchange (ETDEWEB)

Close, F. E.

1973-04-15

The report is based on a series of lectures given at Daresbury Laboratory on 2 to 12 Apri1 1973. It is stated that the purpose was to show the reasons why parton models describe the data, show what other phenomena can be understood and what predictions can be made within the parton hypothesis. The report is in sections: elastic electron scattering; inelastic electron scattering; deep inelastic scattering and partons; structure functions and surn rules in the quark parton model; inelastic neutrinto scattering; forward Compton scattering; Compton scattering in simple models; a J = 0 fixed pole in Compton scattering; the non-perturbative parton model without tears; the parton model and vector-meson dominance-rivals or partners; do resonances scale; resonances, SU(6) and the quark parton model; towards a dynamical parton model. (UK)

Inverse Compton scattering X-ray source yield optimization with a laser path folding system inserted in a pre-existent RF linac

Energy Technology Data Exchange (ETDEWEB)

Chaleil, A.; Le Flanchec, V.; Binet, A.; Nègre, J.P.; Devaux, J.F.; Jacob, V.; Millerioux, M.; Bayle, A.; Balleyguier, P. [CEA DAM DIF, F-91297 Arpajon (France); Prazeres, R. [CLIO/LCP, Bâtiment 201, Université Paris-Sud, F-91450 Orsay (France)

2016-12-21

An inverse Compton scattering source is under development at the ELSA linac of CEA, Bruyères-le-Châtel. Ultra-short X-ray pulses are produced by inverse Compton scattering of 30 ps-laser pulses by relativistic electron bunches. The source will be able to operate in single shot mode as well as in recurrent mode with 72.2 MHz pulse trains. Within this framework, an optical multipass system that multiplies the number of emitted X-ray photons in both regimes has been designed in 2014, then implemented and tested on ELSA facility in the course of 2015. The device is described from both geometrical and timing viewpoints. It is based on the idea of folding the laser optical path to pile-up laser pulses at the interaction point, thus increasing the interaction probability. The X-ray output gain measurements obtained using this system are presented and compared with calculated expectations.

Polarization observables in Virtual Compton Scattering

Energy Technology Data Exchange (ETDEWEB)

Doria, Luca

2007-10-15

Virtual Compton Scattering (VCS) is an important reaction for understanding nucleon structure at low energies. By studying this process, the generalized polarizabilities of the nucleon can be measured. These observables are a generalization of the already known polarizabilities and will permit theoretical models to be challenged on a new level. More specifically, there exist six generalized polarizabilities and in order to disentangle them all, a double polarization experiment must be performed. Within this work, the VCS reaction p(e,e'p){gamma} was measured at MAMI using the A1 Collaboration three spectrometer setup with Q{sup 2}=0.33 (GeV/c){sup 2}. Using the highly polarized MAMI beam and a recoil proton polarimeter, it was possible to measure both the VCS cross section and the double polarization observables. Already in 2000, the unpolarized VCS cross section was measured at MAMI. In this new experiment, we could confirm the old data and furthermore the double polarization observables were measured for the first time. The data were taken in five periods between 2005 and 2006. In this work, the data were analyzed to extract the cross section and the proton polarization. For the analysis, a maximum likelihood algorithm was developed together with the full simulation of all the analysis steps. The experiment is limited by the low statistics due mainly to the focal plane proton polarimeter efficiency. To overcome this problem, a new determination and parameterization of the carbon analyzing power was performed. The main result of the experiment is the extraction of a new combination of the generalized polarizabilities using the double polarization observables. (orig.)

Polarization observables in Virtual Compton Scattering

International Nuclear Information System (INIS)

Doria, Luca

2007-10-01

Virtual Compton Scattering (VCS) is an important reaction for understanding nucleon structure at low energies. By studying this process, the generalized polarizabilities of the nucleon can be measured. These observables are a generalization of the already known polarizabilities and will permit theoretical models to be challenged on a new level. More specifically, there exist six generalized polarizabilities and in order to disentangle them all, a double polarization experiment must be performed. Within this work, the VCS reaction p(e,e'p)γ was measured at MAMI using the A1 Collaboration three spectrometer setup with Q 2 =0.33 (GeV/c) 2 . Using the highly polarized MAMI beam and a recoil proton polarimeter, it was possible to measure both the VCS cross section and the double polarization observables. Already in 2000, the unpolarized VCS cross section was measured at MAMI. In this new experiment, we could confirm the old data and furthermore the double polarization observables were measured for the first time. The data were taken in five periods between 2005 and 2006. In this work, the data were analyzed to extract the cross section and the proton polarization. For the analysis, a maximum likelihood algorithm was developed together with the full simulation of all the analysis steps. The experiment is limited by the low statistics due mainly to the focal plane proton polarimeter efficiency. To overcome this problem, a new determination and parameterization of the carbon analyzing power was performed. The main result of the experiment is the extraction of a new combination of the generalized polarizabilities using the double polarization observables. (orig.)

Optimal inequalities for the subtraction functions of the proton Compton scattering dispersion theory

International Nuclear Information System (INIS)

Caprini, I.

1982-06-01

Upper and lower bounds upon the subtraction functions required in the dispersion theory of the proton Compton process are derived in a framework wbich optimally exploits the gauge invariance, the fixed-t analyticity and the s-u crossing properties of the scattering amplitudes, together with the consequences of the s, u-channel unitarity. The bounds, which are expressed only in terms of measurable s, u-channel physical quantities, without any reference to model dependent annihilation channel contributions, appear to be quite restrictive for some values of the momentum transfer t. The results are significant for removing the sign ambiguity of the pion decay constant. Fsub(p) and for the estimation of the electromagnetic polarizabilities of the proton. (author)

Beam dynamics simulation in the X-ray Compton source

Energy Technology Data Exchange (ETDEWEB)

Gladkikh, P.; Karnaukhov, I.; Telegin, Yu.; Shcherbakov, A. E-mail: shcherbakov@kipt.kharkov.ua; Zelinsky, A

2002-05-01

At the National Science Center 'Kharkov Institute of Physics and Technology' the X-ray source based on Compton scattering has been developed. The computer code for simulation of electron beam dynamics with taking into account the Compton scattering effect based on Monte Carlo method is described in this report. The first results of computer simulation of beam dynamics with electron-photon interaction, parameters of electron and photon beams are presented. Calculations were carried out with the lattice of synchrotron light source SRS-800 Ukrainian Synchrotron Center.

Dual parametrization of the proton generalized parton distribution functions H and E, and description of the deeply virtual Compton scattering cross sections and asymmetries

International Nuclear Information System (INIS)

Guzey, V.; Teckentrup, T.

2006-01-01

We develop the minimal model of a new leading order parametrization of generalized parton distributions (GPDs) introduced by Polyakov and Shuvaev. The model for GPDs H and E is formulated in terms of the forward quark distributions, the Gegenbauer moments of the D-term, and the forward limit of the GPD E. The model is designed primarily for small and medium-size values of x B , x B ≤0.2. We examine two different models of the t dependence of the GPDs: the factorized exponential model and the nonfactorized Regge-motivated model. Using our model, we successfully described the deeply virtual Compton scattering (DVCS) cross section measured by H1 and ZEUS, the moments of the beam-spin A LU sinφ , the beam-charge A C cosφ , and the transversely polarized target A UT sinφcosφ DVCS asymmetries measured by HERMES and A LU sinφ measured by CLAS. The data on A C cosφ prefer the Regge-motivated model of the t dependence of the GPDs. The data on A UT sinφcosφ indicate that the u and d quarks carry only a small fraction of the proton total angular momentum

The development of a Compton lung densitometer

Energy Technology Data Exchange (ETDEWEB)

Loo, B.W.; Goulding, F.S.; Madden, N.W.; Simon, D.S.

1988-11-01

A field instrument is being developed for the non-invasive determination of absolute lung density using unique Compton backscattering techniques. A system consisting of a monoenergetic gamma-ray beam and a shielded high resolution high-purity-germanium (HPGe) detector in a close-coupled geometry is designed to minimize errors due to multiple scattering and uncontrollable attenuation in the chestwall. Results of studies on system performance with phantoms, the optimization of detectors, and the fabrication of a practical gamma-ray source are presented. 3 refs., 6 figs., 2 tabs.

The development of a Compton lung densitometer

International Nuclear Information System (INIS)

Loo, B.W.; Goulding, F.S.; Madden, N.W.; Simon, D.S.

1988-11-01

A field instrument is being developed for the non-invasive determination of absolute lung density using unique Compton backscattering techniques. A system consisting of a monoenergetic gamma-ray beam and a shielded high resolution high-purity-germanium (HPGe) detector in a close-coupled geometry is designed to minimize errors due to multiple scattering and uncontrollable attenuation in the chestwall. Results of studies on system performance with phantoms, the optimization of detectors, and the fabrication of a practical gamma-ray source are presented. 3 refs., 6 figs., 2 tabs

Protein aggregation studied by forward light scattering and light transmission analysis

Science.gov (United States)

Penzkofer, A.; Shirdel, J.; Zirak, P.; Breitkreuz, H.; Wolf, E.

2007-12-01

The aggregation of the circadian blue-light photo-receptor cryptochrome from Drosophila melanogaster (dCry) is studied by transmission and forward light scattering measurement in the protein transparent wavelength region. The light scattering in forward direction is caused by Rayleigh scattering which is proportional to the degree of aggregation. The light transmission through the samples in the transparent region is reduced by Mie light scattering in all directions. It depends on the degree of aggregation and the monomer volume fill factor of the aggregates (less total scattering with decreasing monomer volume fill factor of protein globule) allowing a distinction between tightly packed protein aggregation (monomer volume fill factor 1) and loosely packed protein aggregation (monomer volume fill factor less than 1). An increase in aggregation with temperature, concentration, and blue-light exposure is observed. At a temperature of 4 °C and a protein concentration of less than 0.135 mM no dCry aggregation was observed, while at 24 °C and 0.327 mM gelation occurred (loosely packed aggregates occupying the whole solution volume).

LabVIEW-based X-ray detection system for laser compton scattering experiment

International Nuclear Information System (INIS)

Luo Wen; Xu Wang; Pan Qiangyan

2010-01-01

A LabVIEW-based X-ray detection system has been developed for laser-Compton scattering (LCS) experiment at the 100 MeV Linac of the Shanghai Institute of Applied Physics (SINAP). It mainly consists of a Si (Li) detector, readout electronics and a LabVIEW-based Data Acquisition (DAQ), and possesses the functions of signal spectrum displaying, acquisition control and simple online data analysis and so on. The performance test shows that energy and time resolutions of the system are 184 eV at 5.9 keV and ≤ 1% respectively and system instability is found to be 0.3‰ within a week. As a result, this X-ray detection system has low-cost and high-performance features and can meet the requirements of LCS experiment. (authors)

Deeply virtual Compton scattering in the Hall A of Jefferson laboratory

International Nuclear Information System (INIS)

Munoz Camacho, C.

2005-12-01

Generalized Parton Distributions (GPDs), introduced in the late 90's, provide a universal description of hadrons in terms of the underlying degrees of freedom of Quantum Chromodynamics: quarks and gluons. GPDs appear in a wide variety of hard exclusive reactions and the advent of high luminosity accelerator facilities has made the study of GPDs accessible to experiment. Deeply Virtual Compton Scattering (DVCS) is the golden process involving GPDs. The first dedicated DVCS experiment ran in the Hall A of Jefferson Lab in Fall 2004. An electromagnetic calorimeter and a plastic scintillator detector were constructed for this experiment, together with specific electronics and acquisition system. The experiment preparation, data taking and analysis are described in this document. Results on the absolute cross section difference for opposite beam helicities provide the first measurement of a linear combination of GPDs as a function of the momentum transfer to the nucleon. (author)

Determination of the mass attenuation coefficients for X-ray fluorescence measurements correction by the Rayleigh to Compton scattering ratio

Science.gov (United States)

Conti, C. C.; Anjos, M. J.; Salgado, C. M.

2014-09-01

X-ray fluorescence technique plays an important role in nondestructive analysis nowadays. The development of equipment, including portable ones, enables a wide assortment of possibilities for analysis of stable elements, even in trace concentrations. Nevertheless, despite of the advantages, one important drawback is radiation self-attenuation in the sample being measured, which needs to be considered in the calculation for the proper determination of elemental concentration. The mass attenuation coefficient can be determined by transmission measurement, but, in this case, the sample must be in slab shape geometry and demands two different setups and measurements. The Rayleigh to Compton scattering ratio, determined from the X-ray fluorescence spectrum, provides a link to the mass attenuation coefficient by means of a polynomial type equation. This work presents a way to construct a Rayleigh to Compton scattering ratio versus mass attenuation coefficient curve by using the MCNP5 Monte Carlo computer code. The comparison between the calculated and literature values of the mass attenuation coefficient for some known samples showed to be within 15%. This calculation procedure is available on-line at www.macx.net.br.

Deeply virtual Compton scattering with the CLAS detector for the study of generalized parton distributions

International Nuclear Information System (INIS)

Girod, F.X.

2006-12-01

The structure of the nucleon, among the first fundamental problems in hadronic physics, is the subject of a renewed interest. The lightest baryonic state has historically been described in two complementary approaches: through elastic scattering, measuring form factors which reflect the spatial shape of charge distributions, and through deep inelastic scattering, providing access to parton distribution functions which encode the momentum content carried by the constituents. The recently developed formalism of Generalized Parton Distributions unifies those approaches and provides access to new informations. The cleanest process sensitive to GPDs is the deeply virtual Compton scattering (DVCS) contributing to the ep → epγ reaction. This work deals with a dedicated experiment accomplished with the CLAS detector, completed with two specific equipments: a lead tungstate calorimeter covering photon detection at small angles, and a superconducting solenoid actively shielding the electromagnetic background. The entire project is covered: from the upgrade of the experimental setup, through the update of the software, data taking and analysis, up to a first comparison of the beam spin asymmetry to model predictions. (author)

Helium Compton Form Factor Measurements at CLAS

Energy Technology Data Exchange (ETDEWEB)

Voutier, Eric J.-M. [Laboratoire de Physique Subatomique et Cosmologie

2013-07-01

The distribution of the parton content of nuclei, as encoded via the generalized parton distributions (GPDs), can be accessed via the deeply virtual Compton scattering (DVCS) process contributing to the cross section for leptoproduction of real photons. Similarly to the scattering of light by a material, DVCS provides information about the dynamics and the spatial structure of hadrons. The sensitivity of this process to the lepton beam polarization allows to single-out the DVCS amplitude in terms of Compton form factors that contain GPDs information. The beam spin asymmetry of the $^4$He($\\vec {\\mathrm e}$,e$' \\gamma ^4$He) process was measured in the experimental Hall B of the Jefferson Laboratory to extract the real and imaginary parts of the twist-2 Compton form factor of the $^4$He nucleus. The experimental results reported here demonstrate the relevance of this method for such a goal, and suggest the dominance of the Bethe-Heitler amplitude to the unpolarized process in the kinematic range explored by the experiment.

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

International Nuclear Information System (INIS)

Airapetian, A.; Akopov, Z.

2009-11-01

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

Beam Diagnostics for Laser Undulator Based on Compton Backward Scattering

CERN Document Server

Kuroda, R

2005-01-01

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

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

International Nuclear Information System (INIS)

Airapetian, A.; Akopov, Z.

2012-06-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2012-06-15

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

Forward-jet production in deep inelastic ep scattering at HERA

Energy Technology Data Exchange (ETDEWEB)

Chekanov, S.; Derrick, M.; Magill, S. [Argonne National Lab., IL (US)] (and others)

2007-07-15

Forward jet cross sections have been measured in neutral current deep inelastic scattering at low Bjorken-x with the ZEUS detector at HERA using an integrated luminosity of 81.8 pb{sup -1}. Measurements are presented for inclusive forward jets as well as for forward jets accompanied by a dijet system. The explored phase space, with jet pseudorapidity up to 4.3 is expected to be particularly sensitive to the dynamics of QCD parton evolution at low x. The measurements are compared to fixed-order QCD calculations and to leading-order parton-shower Monte Carlo models. (orig.)

Forward-jet production in deep inelastic ep scattering at HERA

International Nuclear Information System (INIS)

Chekanov, S.; Derrick, M.; Magill, S.

2007-07-01

Forward jet cross sections have been measured in neutral current deep inelastic scattering at low Bjorken-x with the ZEUS detector at HERA using an integrated luminosity of 81.8 pb -1 . Measurements are presented for inclusive forward jets as well as for forward jets accompanied by a dijet system. The explored phase space, with jet pseudorapidity up to 4.3 is expected to be particularly sensitive to the dynamics of QCD parton evolution at low x. The measurements are compared to fixed-order QCD calculations and to leading-order parton-shower Monte Carlo models. (orig.)

ILC beam energy measurement by means of laser Compton backscattering

Energy Technology Data Exchange (ETDEWEB)

Muchnoi, N. [Budker Inst. for Nuclear Physics, Novosibirsk (Russian Federation); Schreiber, H.J.; Viti, M. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)

2008-10-15

A novel, non-invasive method of measuring the beam energy at the International Linear Collider is proposed. Laser light collides head-on with beam particles and either the energy of the Compton scattered electrons near the kinematic end-point is measured or the positions of the Compton backscattered {gamma}-rays, the edge electrons and the unscattered beam particles are recorded. A compact layout for the Compton spectrometer is suggested. It consists of a bending magnet and position sensitive detectors operating in a large radiation environment. Several options for high spatial resolution detectors are discussed. Simulation studies support the use of an infrared or green laser and quartz fiber detectors to monitor the backscattered photons and edge electrons. Employing a cavity monitor, the beam particle position downstream of the magnet can be recorded with submicrometer precision. Such a scheme provides a feasible and promising method to access the incident beam energy with precisions of 10{sup -4} or better on a bunch-to-bunch basis while the electron and positron beams are in collision. (orig.)

ILC beam energy measurement by means of laser Compton backscattering

International Nuclear Information System (INIS)

Muchnoi, N.; Schreiber, H.J.; Viti, M.

2008-10-01

A novel, non-invasive method of measuring the beam energy at the International Linear Collider is proposed. Laser light collides head-on with beam particles and either the energy of the Compton scattered electrons near the kinematic end-point is measured or the positions of the Compton backscattered γ-rays, the edge electrons and the unscattered beam particles are recorded. A compact layout for the Compton spectrometer is suggested. It consists of a bending magnet and position sensitive detectors operating in a large radiation environment. Several options for high spatial resolution detectors are discussed. Simulation studies support the use of an infrared or green laser and quartz fiber detectors to monitor the backscattered photons and edge electrons. Employing a cavity monitor, the beam particle position downstream of the magnet can be recorded with submicrometer precision. Such a scheme provides a feasible and promising method to access the incident beam energy with precisions of 10 -4 or better on a bunch-to-bunch basis while the electron and positron beams are in collision. (orig.)

Repair for scattering expansion truncation errors in transport calculations

International Nuclear Information System (INIS)

Emmett, M.B.; Childs, R.L.; Rhoades, W.A.

1980-01-01

Legendre expansion of angular scattering distributions is usually limited to P 3 in practical transport calculations. This truncation often results in non-trivial errors, especially alternating negative and positive lateral scattering peaks. The effect is especially prominent in forward-peaked situations such as the within-group component of the Compton Scattering of gammas. Increasing the expansion to P 7 often makes the peaks larger and narrower. Ward demonstrated an accurate repair, but his method requires special cross section sets and codes. The DOT IV code provides fully-compatible, but heuristic, repair of the erroneous scattering. An analytical Klein-Nishina estimator, newly available in the MORSE code, allows a test of this method. In the MORSE calculation, particle scattering histories are calculated in the usual way, with scoring by an estimator routine at each collision site. Results for both the conventional P 3 estimator and the analytical estimator were obtained. In the DOT calculation, the source moments are expanded into the directional representation at each iteration. Optionally a sorting procedure removes all negatives, and removes enough small positive values to restore particle conservation. The effect of this is to replace the alternating positive and negative values with positive values of plausible magnitude. The accuracy of those values is examined herein

Electron density values of various human tissues: in vitro Compton scatter measurements and calculated ranges

International Nuclear Information System (INIS)

Shrimpton, P.C.

1981-01-01

Accurate direct measurements of electron density have been performed on specimens from 10 different tissue types of the human body, representing the major organs, using a Compton scatter technique. As a supplement to these experimental values, calculations have been carried out to determine the electron densities expected for these tissue types. The densities observed are in good agreement with the broad ranges deduced from the basic data previously published. The results of both the in vitro sample measurements and the approximate calculations indicate that the electron density of most normal healthy soft tissue can be expected to fall within the fairly restricted range of +- 5% around 3.4 X 10 23 electrons per cm 3 . The obvious exception to this generalisation is the result for lung tissue, which falls considerably below this range owing to the high air content inherent in its construction. In view of such an overall limited variation with little difference between tissues, it would appear that electron density alone is likely to be a rather poor clinical parameter for tissue analysis, with high accuracy and precision being essential in any in vivo Compton measurements for imaging or diagnosis on specific organs. (author)

Determination of the mass attenuation coefficients for X-ray fluorescence measurements correction by the Rayleigh to Compton scattering ratio

Energy Technology Data Exchange (ETDEWEB)

Conti, C.C., E-mail: ccconti@ird.gov.br [Institute for Radioprotection and Dosimetry – IRD/CNEN, Rio de Janeiro (Brazil); Physics Institute, State University of Rio de Janeiro – UERJ, Rio de Janeiro (Brazil); Anjos, M.J. [Physics Institute, State University of Rio de Janeiro – UERJ, Rio de Janeiro (Brazil); Salgado, C.M. [Nuclear Engineering Institute – IEN/CNEN, Rio de Janeiro (Brazil)

2014-09-15

Highlights: •This work describes a procedure for sample self-absorption correction. •The use of Monte Carlo simulation to calculate the mass attenuation coefficients curve was effective. •No need for transmission measurement, saving time, financial resources and effort. •This article provides de curves for the 90° scattering angle. •Calculation on-line at (www.macx.net.br). -- Abstract: X-ray fluorescence technique plays an important role in nondestructive analysis nowadays. The development of equipment, including portable ones, enables a wide assortment of possibilities for analysis of stable elements, even in trace concentrations. Nevertheless, despite of the advantages, one important drawback is radiation self-attenuation in the sample being measured, which needs to be considered in the calculation for the proper determination of elemental concentration. The mass attenuation coefficient can be determined by transmission measurement, but, in this case, the sample must be in slab shape geometry and demands two different setups and measurements. The Rayleigh to Compton scattering ratio, determined from the X-ray fluorescence spectrum, provides a link to the mass attenuation coefficient by means of a polynomial type equation. This work presents a way to construct a Rayleigh to Compton scattering ratio versus mass attenuation coefficient curve by using the MCNP5 Monte Carlo computer code. The comparison between the calculated and literature values of the mass attenuation coefficient for some known samples showed to be within 15%. This calculation procedure is available on-line at (www.macx.net.br)

Discrete ordinates transport methods for problems with highly forward-peaked scattering

International Nuclear Information System (INIS)

Pautz, S.D.

1998-04-01

The author examines the solutions of the discrete ordinates (S N ) method for problems with highly forward-peaked scattering kernels. He derives conditions necessary to obtain reasonable solutions in a certain forward-peaked limit, the Fokker-Planck (FP) limit. He also analyzes the acceleration of the iterative solution of such problems and offer improvements to it. He extends the analytic Fokker-Planck limit analysis to the S N equations. This analysis shows that in this asymptotic limit the S N solution satisfies a pseudospectral discretization of the FP equation, provided that the scattering term is handled in a certain way (which he describes) and that the analytic transport solution satisfies an analytic FP equation. Similar analyses of various spatially discretized S N equations reveal that they too produce solutions that satisfy discrete FP equations, given the same provisions. Numerical results agree with these theoretical predictions. He defines a multidimensional angular multigrid (ANMG) method to accelerate the iterative solution of highly forward-peaked problems. The analyses show that a straightforward application of this scheme is subject to high-frequency instabilities. However, by applying a diffusive filter to the ANMG corrections he is able to stabilize this method. Fourier analyses of model problems show that the resulting method is effective at accelerating the convergence rate when the scattering is forward-peaked. The numerical results demonstrate that these analyses are good predictors of the actual performance of the ANMG method

Applicability of compton imaging in nuclear decommissioning activities

International Nuclear Information System (INIS)

Ljubenov, V.Lj.; Marinkovic, P.M.

2002-01-01

During the decommissioning of nuclear facilities significant part of the activities is related to the radiological characterization, waste classification and management. For these purposes a relatively new imaging technique, based on information from the gamma radiation that undergoes Compton scattering, is applicable. Compton imaging systems have a number of advantages for nuclear waste characterization, such as identifying hot spots in mixed waste in order to reduce the volume of high-level waste requiring extensive treatment or long-term storage, imaging large contaminated areas and objects etc. Compton imaging also has potential applications for monitoring of production, transport and storage of nuclear materials and components. This paper discusses some system design requirements and performance specifications for these applications. The advantages of Compton imaging are compared to competing imaging techniques. (author)

A Spectral Geometrical Model for Compton Scatter Tomography Based on the SSS Approximation

DEFF Research Database (Denmark)

Kazantsev, Ivan G.; Olsen, Ulrik Lund; Poulsen, Henning Friis

2016-01-01

The forward model of single scatter in the Positron Emission Tomography for a detector system possessing an excellent spectral resolution under idealized geometrical assumptions is investigated. This model has the form of integral equations describing a flux of photons emanating from the same ann...

Laser Compton polarimetry at JLab and MAMI. A status report

International Nuclear Information System (INIS)

Diefenbach, J.; Imai, Y.; Han Lee, J.; Maas, F.; Taylor, S.

2007-01-01

For modern parity violation experiments it is crucial to measure and monitor the electron beam polarization continuously. In the recent years different high-luminosity concepts, for precision Compton backscattering polarimetry, have been developed, to be used at modern CW electron beam accelerator facilities. As Compton backscattering polarimetry is free of intrinsic systematic uncertainties, it can be a superior alternative to other polarimetry techniques such as Moeller and Mott scattering. State-of-the-art high-luminosity Compton backscattering designs currently in use and under development at JLab and Mainz are compared to each other. The latest results from the Mainz A4 Compton polarimeter are presented. (orig.)

Gamma radiation compton scattering effect from the Ukrytie Object on the radiation situation at the Chernobyl' NPP territory

International Nuclear Information System (INIS)

Alekseeva, E.A.; Volkovich, A.G.; Koba, G.I.; Liksonov, V.I.; Stepanov, V.E.; Tyurin, A.S.; Urutskoev, L.I.; Chesnokov, A.V.

1989-01-01

With the aim of determination of the angular distribution of the gamma-radiation (GR) exposure dose rate (EDR) around the Ukrytie Object (UO) are described the measurement results of GR EDR in July 1988 at the territory, adjoining to UO. The conclusion is made that the main contribution into EDR ensures GR, scattered as a result of the Compton effect on air molecules and that the contribution of the NPP territory is small. 10 figs.; 3 tabs

X-band RF gun and linac for medical Compton scattering X-ray source

International Nuclear Information System (INIS)

Dobashi, Katsuhito; Uesaka, Mitsuru; Fukasawa, Atsushi; Sakamoto, Fumito; Ebina, Futaro; Ogino, Haruyuki; Urakawa, Junji; Higo, Toshiyasu; Akemoto, Mitsuo; Hayano, Hitoshi; Nakagawa, Keiichi

2004-01-01

Compton scattering hard X-ray source for 10-80 keV are under construction using the X-band (11.424 GHz) electron linear accelerator and YAG laser at Nuclear Engineering Research laboratory, University of Tokyo. This work is a part of the national project on the development of advanced compact medical accelerators in Japan. National Institute for Radiological Science is the host institute and U.Tokyo and KEK are working for the X-ray source. Main advantage is to produce tunable monochromatic hard (10-80 keV) X-rays with the intensities of 108-1010 photons/s (at several stages) and the table-top size. Second important aspect is to reduce noise radiation at a beam dump by adopting the deceleration of electrons after the Compton scattering. This realizes one beamline of a 3rd generation SR source at small facilities without heavy shielding. The final goal is that the linac and laser are installed on the moving gantry. We have designed the X-band (11.424 GHz) traveling-wave-type linac for the purpose. Numerical consideration by CAIN code and luminosity calculation are performed to estimate the X-ray yield. X-band thermionic-cathode RF-gun and RDS(Round Detuned Structure)-type X-band accelerating structure are applied to generate 50 MeV electron beam with 20 pC microbunches (104) for 1 microsecond RF macro-pulse. The X-ray yield by the electron beam and Q-switch Nd:YAG laser of 2 J/10 ns is 107 photons/RF-pulse (108 photons/sec at 10 pps). We design to adopt a technique of laser circulation to increase the X-ray yield up to 109 photons/pulse (1010 photons/s). 50 MW X-band klystron and compact modulator have been constructed and now under tuning. The construction of the whole system has started. X-ray generation and medical application will be performed in the early next year

X-band RF gun and linac for medical Compton scattering X-ray source

Science.gov (United States)

Dobashi, Katsuhito; Uesaka, Mitsuru; Fukasawa, Atsushi; Sakamoto, Fumito; Ebina, Futaro; Ogino, Haruyuki; Urakawa, Junji; Higo, Toshiyasu; Akemoto, Mitsuo; Hayano, Hitoshi; Nakagawa, Keiichi

2004-12-01

Compton scattering hard X-ray source for 10-80 keV are under construction using the X-band (11.424 GHz) electron linear accelerator and YAG laser at Nuclear Engineering Research laboratory, University of Tokyo. This work is a part of the national project on the development of advanced compact medical accelerators in Japan. National Institute for Radiological Science is the host institute and U.Tokyo and KEK are working for the X-ray source. Main advantage is to produce tunable monochromatic hard (10-80 keV) X-rays with the intensities of 108-1010 photons/s (at several stages) and the table-top size. Second important aspect is to reduce noise radiation at a beam dump by adopting the deceleration of electrons after the Compton scattering. This realizes one beamline of a 3rd generation SR source at small facilities without heavy shielding. The final goal is that the linac and laser are installed on the moving gantry. We have designed the X-band (11.424 GHz) traveling-wave-type linac for the purpose. Numerical consideration by CAIN code and luminosity calculation are performed to estimate the X-ray yield. X-band thermionic-cathode RF-gun and RDS(Round Detuned Structure)-type X-band accelerating structure are applied to generate 50 MeV electron beam with 20 pC microbunches (104) for 1 microsecond RF macro-pulse. The X-ray yield by the electron beam and Q-switch Nd:YAG laser of 2 J/10 ns is 107 photons/RF-pulse (108 photons/sec at 10 pps). We design to adopt a technique of laser circulation to increase the X-ray yield up to 109 photons/pulse (1010 photons/s). 50 MW X-band klystron and compact modulator have been constructed and now under tuning. The construction of the whole system has started. X-ray generation and medical application will be performed in the early next year.

Compton scatter in germanium and its effect on imaging with gamma-ray position-sensitive detectors

International Nuclear Information System (INIS)

Sherman, I.S.; Strauss, M.G.; Brenner, R.

1978-01-01

The spatial spread due to Compton scatter in Ge was measured to study the reduction in image contrast and signal-to-noise ratio (S/N) resulting from erroneous readout in Ge position-sensitive detectors. The step response revealing this spread was obtained by scanning with a 122 keV γ-ray beam across a boundary of two sectors of a slotted coaxial Ge(Li) detector that is 40 mm diameter by 22 mm long. The derived line-spread function at 140 keV (/sup 99m/Tc) exhibits much shorter but thicker tails than those due to scatter in tissue as observed with a NaI detector through 5.5 cm of scattering material. Convolutions of rectangular profiles of voids with the Ge(Li) line-spread function show marked deterioration in contrast for voids less than 10 mm across, which in turn results in even greater deterioration of the S/N. As a result, the contrast for voids in Ge images is only 20 to 30 percent higher than that in NaI and the S/N is only comparable for equal detector areas. The degradation in image contrast due to scatter in Ge detectors can be greatly reduced by either using thin detectors (approximately 5 mm), where scatter virtually does not exist, or by using thicker detectors and rejecting scatter electronically. To reduce the effects of scatter on the S/N as well as on contrast, the erroneous position readouts must actually be corrected. A more realizable approach to achieving the ultimate potential of Ge detectors may be a scanning array of discrete detectors (not position sensitive) in which readout is not affected by scatter

The zerology of kaon-nucleon forward scattering amplitudes

International Nuclear Information System (INIS)

Dumbrajs, O.

1981-01-01

It has been realized for a long time that zeros of the forward kaon-nucleon scattering amplitudes are useful in correlating different low and high-energy scattering parameters and in providing a consistency test of available data. The simplest possibility of exploring zeros is to evaluate the ordinary dispersion relations in the complex energy plane. The more natural way of bringing zeros of amplitudes into play is to consider either one of the more sophisticated forms of dispersion relations: i) phase dispersion relations, ii) inverse-amplitude dispersion relations, iii) logarithmic dispersion relations, or to apply the maximum modulus theorem and a factorization theorem. The author concentrates on the use of logarithmic dispersion relations because this approach seems to be the most convenient one for future extensions to nonforward scattering data analyses based on the zeros of the amplitude. (Auth.)

Efficient SPECT scatter calculation in non-uniform media using correlated Monte Carlo simulation

International Nuclear Information System (INIS)

Beekman, F.J.

1999-01-01

Accurate simulation of scatter in projection data of single photon emission computed tomography (SPECT) is computationally extremely demanding for activity distribution in non-uniform dense media. This paper suggests how the computation time and memory requirements can be significantly reduced. First the scatter projection of a uniform dense object (P SDSE ) is calculated using a previously developed accurate and fast method which includes all orders of scatter (slab-derived scatter estimation), and then P SDSE is transformed towards the desired projection P which is based on the non-uniform object. The transform of P SDSE is based on two first-order Compton scatter Monte Carlo (MC) simulated projections. One is based on the uniform object (P u ) and the other on the object with non-uniformities (P ν ). P is estimated by P-tilde=P SDSE P ν /P u . A tremendous decrease in noise in P-tilde is achieved by tracking photon paths for P ν identical to those which were tracked for the calculation of P u and by using analytical rather than stochastic modelling of the collimator. The method was validated by comparing the results with standard MC-simulated scatter projections (P) of 99m Tc and 201 Tl point sources in a digital thorax phantom. After correction, excellent agreement was obtained between P-tilde and P. The total computation time required to calculate an accurate scatter projection of an extended distribution in a thorax phantom on a PC is a only few tens of seconds per projection, which makes the method attractive for application in accurate scatter correction in clinical SPECT. Furthermore, the method removes the need of excessive computer memory involved with previously proposed 3D model-based scatter correction methods. (author)

Mössbauer forward scattering: time-domain spectra

Energy Technology Data Exchange (ETDEWEB)

Sadykov, E. K., E-mail: esadykov@kpfu.ru; Yurichuk, A. A.; Gainov, R. R.; Vagizov, F. G. [Kazan (Volga Region) Federal University (Russian Federation)

2016-12-15

The transmission of the Mössbauer radiation through an absorber being in the acoustic oscillation mode under forward scattering (FS) conditions has been analyzed. The modification of the existing models of the FS spectra (frequency and time) formation to the case of the arbitrary phase correlation of nuclear oscillations in the sample has been proposed. An adequate description of the time delayed experiments with the {sup 57}Fe Mössbauer resonance using the modulation of the single-photon wave packet by acoustic field has been obtained. One has been done in the frame of the Raman scattering of Mössbauer photons. The models extended this way can be used to control the degree of phase correlation of nuclear oscillations (or other processes) induced in the sample by external fields.

Development of a compact x-ray source via laser compton scattering at KEK-LUCX

International Nuclear Information System (INIS)

Sakaue, Kazuyuki; Washio, Masakazu; Aryshev, Alexander; Araki, Sakae; Urakawa, Junji; Terunuma, Nobuhiro; Fukuda, Masafumi; Miyoshi, Toshinobu; Takeda, Ayaki

2013-01-01

The compact X-ray source based on Laser-Compton scattering (LCS) has been developed at LUCX (Laser Undulator Compact X-ray source) facility in KEK. The multi-bunch high quality electron beam produced by a standing wave 3.6 cell RF Gun and accelerated by the followed S-band normal conducting 12 cells standing wave 'Booster' linear accelerator is scattered off the laser beam stored in the optical cavity. The 4-mirror planar optical cavity with finesse 335 is used. The MCP (Micro-Channer Plate) detector as well as SOI (Silicon-On-Insulator) pixel sensor was used for scattered X-ray detection. The SOI pixel sensor has been used for LCS X-ray detection for the first time and has demonstrated high spatial resolution and high SN ratio X-ray detection that in turn lead to clearest X-ray images achieved by LCS X-ray. We have also achieved generation of 6.38x10 6 ph./sec., which is more than 30 times larger LCS X-ray flux in comparison with our previous results. The complete details of LUCX LCS X-ray source, specifications of both electron and laser beams, and the results of LCS X-ray generation experiments are reported in this paper. (author)

Forward elastic scattering above the physical threshold

Energy Technology Data Exchange (ETDEWEB)

Avila, R.F. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Inst. de Matematica, Estatistica e Computacao Cientifica; Menon, M.J. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Inst. de Fisica Gleb Wataghin

2006-07-01

Making use of the 'extended derivative dispersion relations', recently introduced by Avila and Menon, we analyze forward elastic proton-proton and antiproton-proton scattering at any energy above the physical threshold ({radical}s=2m{sub p} {approx} 1,88 GeV). The analysis is based on an analytical parametrization for the total cross section with leading triple pole pomeron (high energies) and full nondegenerated secondary reggeons (intermediate and low energies). Experimental data on total cross section and the ratio r between the real and imaginary parts of the forward amplitude are simultaneously fitted with the CERN-Minuit code and energy cutoff at 4 GeV. We show that, the results are exactly the same as those obtained through standard integral dispersion relations. Physical implications of the results in the pomeron-reggeon context are also discussed. (author)

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.)

Radiative heat transfer in strongly forward scattering media using the discrete ordinates method

Science.gov (United States)

Granate, Pedro; Coelho, Pedro J.; Roger, Maxime

2016-03-01

The discrete ordinates method (DOM) is widely used to solve the radiative transfer equation, often yielding satisfactory results. However, in the presence of strongly forward scattering media, this method does not generally conserve the scattering energy and the phase function asymmetry factor. Because of this, the normalization of the phase function has been proposed to guarantee that the scattering energy and the asymmetry factor are conserved. Various authors have used different normalization techniques. Three of these are compared in the present work, along with two other methods, one based on the finite volume method (FVM) and another one based on the spherical harmonics discrete ordinates method (SHDOM). In addition, the approximation of the Henyey-Greenstein phase function by a different one is investigated as an alternative to the phase function normalization. The approximate phase function is given by the sum of a Dirac delta function, which accounts for the forward scattering peak, and a smoother scaled phase function. In this study, these techniques are applied to three scalar radiative transfer test cases, namely a three-dimensional cubic domain with a purely scattering medium, an axisymmetric cylindrical enclosure containing an emitting-absorbing-scattering medium, and a three-dimensional transient problem with collimated irradiation. The present results show that accurate predictions are achieved for strongly forward scattering media when the phase function is normalized in such a way that both the scattered energy and the phase function asymmetry factor are conserved. The normalization of the phase function may be avoided using the FVM or the SHDOM to evaluate the in-scattering term of the radiative transfer equation. Both methods yield results whose accuracy is similar to that obtained using the DOM along with normalization of the phase function. Very satisfactory predictions were also achieved using the delta-M phase function, while the delta

Development of a Watt-level gamma-ray source based on high-repetition-rate inverse Compton scattering

Energy Technology Data Exchange (ETDEWEB)

Mihalcea, D.; Murokh, A.; Piot, P.; Ruan, J.

2017-07-01

A high-brilliance (~10²² photon s^-1 mm^-2 mrad^-2 /0.1%) gamma-ray source experiment is currently being planned at Fermilab (E_γ≃1.1 MeV). The source implements a high-repetition-rate inverse Compton scattering by colliding electron bunches formed in a ~300-MeV superconducting linac with a high-intensity laser pulse. This paper describes the design rationale along with some of technical challenges associated to producing high-repetition-rate collision. The expected performances of the gamma-ray source are also presented.

Positivity of the real part of the forward scattering amplitude

Science.gov (United States)

Martin, André; Wu, Tai Tsun

2018-01-01

We prove the general theorem that the real part of the crossing even forward two-body scattering amplitude is positive at sufficiently high energies if, above a certain energy, the total cross section increases monotonically to infinity at infinite energy.

Investigation of multimodal forward scatter phenotyping from bacterial colonies

Science.gov (United States)

Kim, Huisung

A rapid, label-free, and elastic light scattering (ELS) based bacterial colony phenotyping technology, bacterial rapid detection using optical scattering technology (BARDOT) provides a successful classification of several bacterial genus and species. For a thorough understanding of the phenomena and overcoming the limitations of the previous design, five additional modalities from a bacterial colony: 3D morphology, spatial optical density (OD) distribution, spectral forward scattering pattern, spectral OD, and surface backward reflection pattern are proposed to enhance the classification/identification ratio, and the feasibilities of each modality are verified. For the verification, three different instruments: integrated colony morphology analyzer (ICMA), multi-spectral BARDOT (MS-BARDOT) , and multi-modal BARDOT (MM-BARDOT) are proposed and developed. The ICMA can measure 3D morphology and spatial OD distribution of the colony simultaneously. A commercialized confocal displacement meter is used to measure the profiles of the bacterial colonies, together with a custom built optical density measurement unit to interrogate the biophysics behind the collective behavior of a bacterial colony. The system delivers essential information related to the quantitative growth dynamics (height, diameter, aspect ratio, optical density) of the bacterial colony, as well as, a relationship in between the morphological characteristics of the bacterial colony and its forward scattering pattern. Two different genera: Escherichia coli O157:H7 EDL933, and Staphylococcus aureus ATCC 25923 are selected for the analysis of the spatially resolved growth dynamics, while, Bacillus spp. such as B. subtilis ATCC 6633, B. cereus ATCC 14579, B. thuringiensis DUP6044, B. polymyxa B719W, and B. megaterium DSP 81319, are interrogated since some of the Bacillus spp. provides strikingly different characteristics of ELS patterns, and the origin of the speckle patterns are successfully correlated with

Increase in compton scattering of gamma rays passing along metal surface

International Nuclear Information System (INIS)

Grigor'ev, A.N.; Bilyk, Z.V.; Sakun, A.V.; Marushchenko, V.V.; Chernyavskij, O.Yu.; Litvinov, Yu.V.

2014-01-01

The paper considers experimental study of changes in energy of 137 Cs gamma source as gamma rays pass along metal surface. Decrease in gamma energy was examined by reducing the number of gamma rays in the complete absorption peak to the Compton length level and increasing the Compton effect. The number of gamma rays in the complete absorption peak decreases by 3.5 times in the angle range under study

Development of Compton gamma-ray sources at LLNL

Energy Technology Data Exchange (ETDEWEB)

Albert, F.; Anderson, S. G.; Ebbers, C. A.; Gibson, D. J.; Hartemann, F. V.; Marsh, R. A.; Messerly, M. J.; Prantil, M. A.; Wu, S.; Barty, C. P. J. [Lawrence Livermore National Laboratory, NIF and Photon Science, 7000 East avenue, Livermore, CA 94550 (United States)

2012-12-21

Compact Compton scattering gamma-ray sources offer the potential of studying nuclear photonics with new tools. The optimization of such sources depends on the final application, but generally requires maximizing the spectral density (photons/eV) of the gamma-ray beam while simultaneously reducing the overall bandwidth on target to minimize noise. We have developed an advanced design for one such system, comprising the RF drive, photoinjector, accelerator, and electron-generating and electron-scattering laser systems. This system uses a 120 Hz, 250 pC, 2 ps, 0.35 mm mrad electron beam with 250 MeV maximum energy in an X-band accelerator scattering off a 150 mJ, 10 ps, 532 nm laser to generate 5 Multiplication-Sign 10{sup 10} photons/eV/s/Sr at 0.5 MeV with an overall bandwidth of less than 1%. The source will be able to produce photons up to energies of 2.5 MeV. We also discuss Compton scattering gamma-ray source predictions given by numerical codes.

The Compton Camera - medical imaging with higher sensitivity Exhibition LEPFest 2000

CERN Multimedia

2000-01-01

The Compton Camera reconstructs the origin of Compton-scattered X-rays using electronic collimation with Silicon pad detectors instead of the heavy conventional lead collimators in Anger cameras - reaching up to 200 times better sensitivity and a factor two improvement in resolution. Possible applications are in cancer diagnosis, neurology neurobiology, and cardiology.

Photon migration in non-scattering tissue and the effects on image reconstruction

Science.gov (United States)

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)

Radio emission from quasars and BL Lac objects by coherent plasma oscillation and stimulated Compton scattering

International Nuclear Information System (INIS)

Colgate, S.A.; Petschek, A.G.

1978-01-01

The full radiation spectrum of quasars and BL Lac objects is interpreted as due to a dependent combination of a soft plasma oscillation source at 2ν/sub P/ and bremsstrahlung. Previous work of the plasma oscillation radiation is extended into the radio part of the spectrum and it is shown how the high brightness temperature observations of BL Lac objects [kT/sub b/ (100 MHz) approximate = 3 x 10 5 mc 2 ] are a reasonable consequence of a lower external plasma density and ejection as required for the observed lack of emission lines. Two extreme cases are considered, the one where the plasma oscillations are suddenly extinguished and only stimulated Compton scattering remains and a second case of a constant source of plasma oscillations but a graded surface density. The first case gives 1/100 of the required brightness temperature and the second gives 100 times too large a brightness temperature and also a x 10 too large a radius. It is believed reasonable to invoke a combination of both processes to explain the observed radio spectrum. This model circumvents the self-Compton x-ray flux difficulty of incoherent synchrotron emission

Measurements of Polarization Transfers in Real Compton Scattering by a proton target at JLAB. A new source of information on the 3D shape of the nucleon

Energy Technology Data Exchange (ETDEWEB)

Fanelli, Cristiano V. [Sapienza Univ. of Rome (Italy)

2015-03-01

In this thesis work, results of the analysis of the polarization transfers measured in real Compton scattering (RCS) by the Collaboration E07-002 at the Je fferson Lab Hall-C are presented. The data were collected at large scattering angle (theta_cm = 70deg) and with a polarized incident photon beam at an average energy of 3.8 GeV. Such a kind of experiments allows one to understand more deeply the reaction mechanism, that involves a real photon, by extracting both Compton form factors and Generalized Parton Distributions (GPDs) (also relevant for possibly shedding light on the total angular momentum of the nucleon). The obtained results for the longitudinal and transverse polarization transfers K_LL and K_LT, are of crucial importance, since they confirm unambiguously the disagreement between experimental data and pQCD prediction, as it was found in E99-114 experiment, and favor the Handbag mechanism. The E99-114 and E07-002 results can contribute to attract new interest on the great yield of the Compton scattering by a nucleon target, as demonstrated by the recent approval of an experimental proposal submitted to the Jefferson Lab PAC 42 for a Wide-angle Compton Scattering experiment, at 8 and 10 GeV Photon Energies. The new experiments approved to run with the updated 12 GeV electron beam at JLab, are characterized by much higher luminosities, and a new GEM tracker is under development to tackle the challenging backgrounds. Within this context, we present a new multistep tracking algorithm, based on (i) a Neural Network (NN) designed for a fast and efficient association of the hits measured by the GEM detector which allows the track identification, and (ii) the application of both a Kalman filter and Rauch-Tung-Striebel smoother to further improve the track reconstruction. The full procedure, i.e. NN and filtering, appears very promising, with high performances in terms of both association effciency and reconstruction accuracy, and these preliminary results will

Time-domain, nuclear-resonant, forward scattering: the classical approach

International Nuclear Information System (INIS)

Hoy, G.R.

1997-01-01

This paper deals with the interaction of electromagnetic radiation with matter assuming the matter to have nuclear transitions in resonance with incident electromagnetic radiation. The source of the radiation is taken to be of two types; natural radioactive gamma decay and synchrotron radiation. Numerical examples using 57 Fe are given for the two types of source radiation. Calculated results are contrasted for the two cases. Electromagnetic radiation produced by recoil-free gamma-ray emission has essentially the natural linewidth. Electromagnetic radiation from a synchrotron, even with the best monochromators available, has a relatively broad-band spectrum, essentially constant for these considerations. Polarization effects are considered. In general, the nuclear-resonant medium changes the polarization of the input radiation on traversing the medium. Calculations are presented to illustrate that synchrotron radiation studies using nuclear-resonant forward scattering have the potential for making high-precision measurements of hyperfine fields and recoilless fractions. An interesting aspect of nuclear-resonant forward scattering, relative to possible gamma-ray laser development, is the so-called 'speed-up' effect

Stochastic Electrodynamics and the Compton effect

International Nuclear Information System (INIS)

Franca, H.M.; Barranco, A.V.

1987-12-01

Some of the main qualitative features of the Compton effect are tried to be described within the realm of Classical Stochastic Electrodynamics (SED). It is found indications that the combined action of the incident wave (frequency ω), the radiation reaction force and the zero point fluctuating electromagnetic fields of SED, are able to given a high average recoil velocity v/c=α/(1+α) to the charged particle. The estimate of the parameter α gives α ∼ ℎω/mc 2 where 2Πℎ is the constant and mc 2 is the rest energy of the particle. It is verified that this recoil is just that necessary to explain the frequency shift, observed in the scattered radiation as due to a classical double Doppler shift. The differential cross section for the radiation scattered by the recoiling charge using classical electromagnetism also calculated. The same expression as obtained by Compton in his fundamental work of 1923 is found. (author) [pt

Forward diffraction amplitude of pp and pp elastic scattering at accelerator energies

International Nuclear Information System (INIS)

Kawasaki, M.; Maehara, T.; Yonezawa, M.

2004-01-01

A simple relation between the total cross section and the forward exponential slope of the elastic differential cross section of pp and pp scattering is indicated. An interpretation of this relation is presented as the formation of a black-disk structure for the elastic diffraction interaction of hadron-hadron scattering at the nonasymptotic energy region

Bin mode estimation methods for Compton camera imaging

International Nuclear Information System (INIS)

Ikeda, S.; Odaka, H.; Uemura, M.; Takahashi, T.; Watanabe, S.; Takeda, S.

2014-01-01

We study the image reconstruction problem of a Compton camera which consists of semiconductor detectors. The image reconstruction is formulated as a statistical estimation problem. We employ a bin-mode estimation (BME) and extend an existing framework to a Compton camera with multiple scatterers and absorbers. Two estimation algorithms are proposed: an accelerated EM algorithm for the maximum likelihood estimation (MLE) and a modified EM algorithm for the maximum a posteriori (MAP) estimation. Numerical simulations demonstrate the potential of the proposed methods

Deeply virtual Compton scattering off an unpolarised hydrogen target at HERMES

Energy Technology Data Exchange (ETDEWEB)

Burns, Jonathan R.T.

2010-08-15

Deeply Virtual Compton Scattering (DVCS) i.e. ep {yields} ep{gamma} is the simplest interaction that allows access to Generalised Parton Distributions (GPDs), a theoretical framework describing nucleon structure. The strong interest in GPDs results from the fact that they can be used to determine the total angular momentum of quarks inside the nucleon and provide a 3-dimensional picture of nucleon structure. The measurement of the DVCS process is facilitated by the interference with a competing interaction known as the Bethe-Heitler process which has the same nal state. DVCS information is obtained from the asymmetrical in distribution of the real photon around the azimuthal angle {phi} at HERMES. Beam charge and beam helicity asymmetries, extracted from DVCS events with an unpolarised hydrogen target recorded during the 2006-2007 and 1996-2007 data taking periods, are presented in this thesis. The asymmetry amplitudes are presented over the range of HERMES kinematic acceptance, with their dependence on kinematic variables t, x{sub B} and Q{sup 2} also shown and compared to a phenomenological model. (orig.)

Development of a Compton camera for prompt-gamma medical imaging

Science.gov (United States)

Aldawood, S.; Thirolf, P. G.; Miani, A.; Böhmer, M.; Dedes, G.; Gernhäuser, R.; Lang, C.; Liprandi, S.; Maier, L.; Marinšek, T.; Mayerhofer, M.; Schaart, D. R.; Lozano, I. Valencia; Parodi, K.

2017-11-01

A Compton camera-based detector system for photon detection from nuclear reactions induced by proton (or heavier ion) beams is under development at LMU Munich, targeting the online range verification of the particle beam in hadron therapy via prompt-gamma imaging. The detector is designed to be capable to reconstruct the photon source origin not only from the Compton scattering kinematics of the primary photon, but also to allow for tracking of the secondary Compton-scattered electrons, thus enabling a γ-source reconstruction also from incompletely absorbed photon events. The Compton camera consists of a monolithic LaBr3:Ce scintillation crystal, read out by a multi-anode PMT acting as absorber, preceded by a stacked array of 6 double-sided silicon strip detectors as scatterers. The detector components have been characterized both under offline and online conditions. The LaBr3:Ce crystal exhibits an excellent time and energy resolution. Using intense collimated 137Cs and 60Co sources, the monolithic scintillator was scanned on a fine 2D grid to generate a reference library of light amplitude distributions that allows for reconstructing the photon interaction position using a k-Nearest Neighbour (k-NN) algorithm. Systematic studies were performed to investigate the performance of the reconstruction algorithm, revealing an improvement of the spatial resolution with increasing photon energy to an optimum value of 3.7(1)mm at 1.33 MeV, achieved with the Categorical Average Pattern (CAP) modification of the k-NN algorithm.

Measurement of Deeply Virtual Compton Scattering and its t-dependence at HERA

CERN Document Server

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.; Dossanov, A.; 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.; 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, 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.; 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, 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.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J.V.; Mozer, M.U.; Mudrinic, M.; Muller, K.; Murin, 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.; 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.; Raspiareza, A.; 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, Ivan; 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.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, K.; 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, Ch.; Wolf, R.; Wunsch, E.; Yeganov, V.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y.C.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.

2008-01-01

A measurement of elastic deeply virtual Compton scattering gamma* p -> gamma p using e-p collision data recorded with the H1 detector at HERA is presented. The analysed data sample corresponds to an integrated luminosity of 145 pb^-1. The cross section is measured as a function of the virtuality Q^2 of the exchanged photon and the centre-of-mass energy W of the gamma*p system in the kinematic domain 6.5 < Q^2 < 80 GeV^2, 30 < W < 140 GeV and |t| < 1 GeV^2, where t denotes the squared momentum transfer at the proton vertex. The cross section is determined differentially in t for different Q^2 and W values and exponential t-slope parameters are derived. The measurements are compared to a NLO QCD calculation based on generalised parton distributions. In the context of the dipole approach, the geometric scaling property of the DVCS cross section is studied for different values of t.

Measurement of deeply virtual Compton scattering and its t-dependence at HERA

Science.gov (United States)

H1 Collaboration; 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.; Dossanov, A.; 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.; 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.; 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.; 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, 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.; Mohamed, A.; 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.; 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.; Raspiareza, A.; 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.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, K.; 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, Ch.; Wolf, R.; Wünsch, E.; Yeganov, V.; Žáček, J.; Zálešák, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y. C.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.

2008-01-01

A measurement of elastic deeply virtual Compton scattering γp→γp using ep collision data recorded with the H1 detector at HERA is presented. The analysed data sample corresponds to an integrated luminosity of 145 pb. The cross section is measured as a function of the virtuality Q of the exchanged photon and the centre-of-mass energy W of the γp system in the kinematic domain 6.5

Low-momentum-transfer nonrelativistic limit of the relativistic impulse approximation expression for Compton-scattering doubly differential cross sections and characterization of their relativistic contributions

International Nuclear Information System (INIS)

LaJohn, L. A.

2010-01-01

The nonrelativistic (nr) impulse approximation (NRIA) expression for Compton-scattering doubly differential cross sections (DDCS) for inelastic photon scattering is recovered from the corresponding relativistic expression (RIA) of Ribberfors [Phys. Rev. B 12, 2067 (1975)] in the limit of low momentum transfer (q→0), valid even at relativistic incident photon energies ω 1 >m provided that the average initial momentum of the ejected electron i > is not too high, that is, i > b 1 >m using nr expressions when θ is small. For example, a 1% accuracy can be obtained when ω 1 =1 MeV if θ 1 increases into the MeV range, the maximum θ at which an accurate Compton peak can be obtained from nr expressions approaches closer to zero, because the θ at which the relativistic shift of CP to higher energy is greatest, which starts at 180 deg. when ω 1 min ,ρ rel ) (where p min is the relativistic version of the z component of the momentum of the initial electron and ρ rel is the relativistic charge density) and K(p min ) on p min . This characterization approach was used as a guide for making the nr QED S-matrix expression for the Compton peak kinematically relativistic. Such modified nr expressions can be more readily applied to large systems than the fully relativistic version.

Comparison of electrothermal atomization diode laser Zeeman- and wavelength-modulated atomic absorption and coherent forward scattering spectrometry

International Nuclear Information System (INIS)

Blecker, Carlo R.; Hermann, Gerd M.

2009-01-01

Atomic absorption and coherent forward scattering spectrometry by using a near-infrared diode laser with and without Zeeman and wavelength modulation were carried out with graphite furnace electrothermal atomization. Analytical curves and limits of detection were compared. The magnetic field was modulated with 50 Hz, and the wavelength of the diode laser with 10 kHz. Coherent forward scattering was measured with crossed and slightly uncrossed polarizers. The results show that the detection limits of atomic absorption spectrometry are roughly the same as those of coherent forward scattering spectrometry with crossed polarizers. According to the theory with bright flicker noise limited laser sources the detection limits and linear ranges obtained with coherent forward scattering spectrometry with slightly uncrossed polarizers are significantly better than those obtained with crossed polarizers and with atomic absorption spectrometry. This is due to the fact that employing approaches of polarization spectroscopy reduce laser intensity fluctuations to their signal carried fractions

Extracting the redox orbitals in Li battery materials with high-resolution x-ray compton scattering spectroscopy.

Science.gov (United States)

Suzuki, K; Barbiellini, B; Orikasa, Y; Go, N; Sakurai, H; Kaprzyk, S; Itou, M; Yamamoto, K; Uchimoto, Y; Wang, Yung Jui; Hafiz, H; Bansil, A; Sakurai, Y

2015-02-27

We present an incisive spectroscopic technique for directly probing redox orbitals based on bulk electron momentum density measurements via high-resolution x-ray Compton scattering. Application of our method to spinel Li_{x}Mn_{2}O_{4}, a lithium ion battery cathode material, is discussed. The orbital involved in the lithium insertion and extraction process is shown to mainly be the oxygen 2p orbital. Moreover, the manganese 3d states are shown to experience spatial delocalization involving 0.16±0.05 electrons per Mn site during the battery operation. Our analysis provides a clear understanding of the fundamental redox process involved in the working of a lithium ion battery.

Forward gluon production in hadron-hadron scattering with Pomeron loops

International Nuclear Information System (INIS)

Iancu, E.

2006-01-01

We discuss new physical phenomena expected in particle production in hadron-hadron collisions at high energy, as a consequence of Pomerons loop effects in the evolution equations for the Color Glass Condensate. We focus on gluon production in asymmetric, 'dilute-dense', collisions: a dilute projectile scatters off a dense hadronic target, whose gluon distribution is highly evolved. This situation is representative for particle production in proton-proton collisions at forward rapidities (say, at LHC) and admits a dipole factorization similar to that of deep inelastic scattering (DIS). We show that at sufficiently large forward rapidities, where the Pomerons loop effects become important in the evolution of the target wavefunction, gluon production is dominated by 'black spots' (saturated gluon configurations) up to very large values of the transverse momentum, well above the average saturation momentum in the target. In this regime, the produced gluon spectrum exhibits diffusive scaling, so like DIS at sufficiently high energy. (authors)

Forward gluon production in hadron-hadron scattering with Pomeron loops

Energy Technology Data Exchange (ETDEWEB)

Iancu, E. [CEA Saclay, Service de Physique Th orique (DSM/SPhT), Unite de recherche associ e au CNRS (URA D2306), 91 - Gif-sur-Yvette (France). Direction des Sciences de la Matiere; Marquet, C.; Soyez, G. [CEA Saclay, Service de Physique Th orique (DSM/SPhT), Unite de recherche associ e au CNRS (URA D2306), 91 - Gif-sur-Yvette (France). Direction des Sciences de la Matiere; Liege Univ., Fundamental Theoretical Physics Group (Belgium)

2006-07-01

We discuss new physical phenomena expected in particle production in hadron-hadron collisions at high energy, as a consequence of Pomerons loop effects in the evolution equations for the Color Glass Condensate. We focus on gluon production in asymmetric, 'dilute-dense', collisions: a dilute projectile scatters off a dense hadronic target, whose gluon distribution is highly evolved. This situation is representative for particle production in proton-proton collisions at forward rapidities (say, at LHC) and admits a dipole factorization similar to that of deep inelastic scattering (DIS). We show that at sufficiently large forward rapidities, where the Pomerons loop effects become important in the evolution of the target wavefunction, gluon production is dominated by 'black spots' (saturated gluon configurations) up to very large values of the transverse momentum, well above the average saturation momentum in the target. In this regime, the produced gluon spectrum exhibits diffusive scaling, so like DIS at sufficiently high energy. (authors)

Measurement of doubly differential collision cross-sections for double-photon Compton scattering of 0.662 MeV gamma rays

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

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

A measurement of the Q2, W and t dependences of deeply virtual Compton scattering at HERA

International Nuclear Information System (INIS)

2009-01-01

Deeply virtual Compton scattering, γ*p → γp, has been measured in e + p collisions at HERA with the ZEUS detector using an integrated luminosity of 61.1 pb -1 . Cross sections are presented as a function of the photon virtuality, Q 2 , and photon-proton centre-of-mass energy, W, for a wide region of the phase space, Q 2 > 1.5 GeV 2 and 40 -1 , is used for the first direct measurement of the differential cross section as a function of t, where t is the square of the four-momentum transfer at the proton vertex.

A measurement of the Q2, W and t dependences of deeply virtual Compton scattering at HERA

International Nuclear Information System (INIS)

Chekanov, S.; Derrick, M.; Magill, S.

2008-12-01

Deeply virtual Compton scattering, γ * p→γp, has been measured in e + p collisions at HERA with the ZEUS detector using an integrated luminosity of 61.1 pb -1 . Cross sections are presented as a function of the photon virtuality, Q 2 , and photon-proton centre-of-mass energy, W, for a wide region of the phase space, Q 2 >1.5 GeV 2 and 40 -1 , is used for the first direct measurement of the differential cross section as a function of t, where t is the square of the four-momentum transfer at the proton vertex. (orig.)

Brilliant GeV gamma-ray flash from inverse Compton scattering in the QED regime

Science.gov (United States)

Gong, Z.; Hu, R. H.; Lu, H. Y.; Yu, J. Q.; Wang, D. H.; Fu, E. G.; Chen, C. E.; He, X. T.; Yan, X. Q.

2018-04-01

An all-optical scheme is proposed for studying laser plasma based incoherent photon emission from inverse Compton scattering in the quantum electrodynamic regime. A theoretical model is presented to explain the coupling effects among radiation reaction trapping, the self-generated magnetic field and the spiral attractor in phase space, which guarantees the transfer of energy and angular momentum from electromagnetic fields to particles. Taking advantage of a prospective ˜ 1023 W cm-2 laser facility, 3D particle-in-cell simulations show a gamma-ray flash with unprecedented multi-petawatt power and brightness of 1.7 × 1023 photons s-1 mm-2 mrad-2/0.1% bandwidth (at 1 GeV). These results bode well for new research directions in particle physics and laboratory astrophysics exploring laser plasma interactions.

Compton Polarimetry at ELSA

International Nuclear Information System (INIS)

Hillert, Wolfgang; Aurand, Bastian; Wittschen, Juergen

2009-01-01

Part of the future polarization program performed at the Bonn accelerator facility ELSA will rely on precision Compton polarimetry of the stored transversely polarized electron beam. Precise and fast polarimetry poses high demands on the light source and the detector which were studied in detail performing numerical simulations of the Compton scattering process. In order to experimentally verify these calculations, first measurements were carried out using an argon ion laser as light source and a prototype version of a counting silicon microstrip detector. Calculated and measured intensity profiles of backscattered photons are presented and compared, showing excellent agreement. Background originating from beam gas radiation turned out to be the major limitation of the polarimeter performance. In order to improve the situation, a new polarimeter was constructed and is currently being set up. Design and expected performance of this polarimeter upgrade are presented.

Deeply virtual Compton scattering in the Hall A of Jefferson laboratory; Diffusion Compton profondement virtuelle dans le Hall A au Jefferson laboratory

Energy Technology Data Exchange (ETDEWEB)

Munoz Camacho, C

2005-12-15

Generalized Parton Distributions (GPDs), introduced in the late 90's, provide a universal description of hadrons in terms of the underlying degrees of freedom of Quantum Chromodynamics: quarks and gluons. GPDs appear in a wide variety of hard exclusive reactions and the advent of high luminosity accelerator facilities has made the study of GPDs accessible to experiment. Deeply Virtual Compton Scattering (DVCS) is the golden process involving GPDs. The first dedicated DVCS experiment ran in the Hall A of Jefferson Lab in Fall 2004. An electromagnetic calorimeter and a plastic scintillator detector were constructed for this experiment, together with specific electronics and acquisition system. The experiment preparation, data taking and analysis are described in this document. Results on the absolute cross section difference for opposite beam helicities provide the first measurement of a linear combination of GPDs as a function of the momentum transfer to the nucleon. (author)

Forward and backward scattering experiments in ultra-cold Rubidium atoms

DEFF Research Database (Denmark)

Kampel, Nir Shlomo

project, we have studied coherent forward scattering in the form of a memory experiment. In such an experiment we convert the input light pulse to an atomic excitation, and at a later time convert back the atomic excitation into the retrieved light pulse. In the first project, we investigate the source...

A Simple Generator of Forward Scattering Functions on Spherical Dielectrics

Directory of Open Access Journals (Sweden)

O. Fiser

1993-04-01

Full Text Available The described program generates the forward scattering functions of dielectrics of spherical shape, while the input parameters are: frequency, radius of the sphere and complex refractive index. The part enabling to evaluate the complex refractive index of water in the dependence on frequency and temperature is added.

An x ray scatter approach for non-destructive chemical analysis of low atomic numbered elements

Science.gov (United States)

Ross, H. Richard

1993-01-01

A non-destructive x-ray scatter (XRS) approach has been developed, along with a rapid atomic scatter algorithm for the detection and analysis of low atomic-numbered elements in solids, powders, and liquids. The present method of energy dispersive x-ray fluorescence spectroscopy (EDXRF) makes the analysis of light elements (i.e., less than sodium; less than 11) extremely difficult. Detection and measurement become progressively worse as atomic numbers become smaller, due to a competing process called 'Auger Emission', which reduces fluorescent intensity, coupled with the high mass absorption coefficients exhibited by low energy x-rays, the detection and determination of low atomic-numbered elements by x-ray spectrometry is limited. However, an indirect approach based on the intensity ratio of Compton and Rayleigh scattered has been used to define light element components in alloys, plastics and other materials. This XRS technique provides qualitative and quantitative information about the overall constituents of a variety of samples.

Production of X-rays by inverse Compton effect; Produccion de rayos X por efecto Compton inverso

Energy Technology Data Exchange (ETDEWEB)

Mainardi, R.T. [Facultad de Matematica, Astronomia y Fisica, Universidad Nacional de Cordoba, 5000 Cordoba (Argentina)

2005-07-01

X-rays and gamma rays of high energy values can be produced by the scattering of low energy photons with high energy electrons, being this a process controlled by the Compton scattering. If a laser beam is used, the x-ray beam inherits the properties of intensity, monochromaticity and collimation from the laser. In this work we analyze the generation of intense x-ray beams of energies between 10 and 100 KeV to be used in a wide range of applications where a high intensity and high degrees of monochromaticity and polarization are important properties to improve image reduce doses and improve radiation treatments. To this purpose we evaluated, using relativistic kinematics the scattered beam properties in terms of the scattering angle. This arrangement is being considered in several worldwide laboratories as an alternative to synchrotron radiation and is referred to as 'table top synchrotron radiation', since it cost of installation is orders of magnitude smaller than a 'synchrotron radiation source'. The radiation beam might exhibit non-linear properties in its interaction with matter, in a similar way as a laser beam and we will investigate how to calibrate and evaluate TLD dosemeters properties, both in low and high intensity fields either mono or polyenergetic in wide spectral energy ranges. (Author)

Space and time dependent boltzmann calculation in the forward backward scattering approximation

International Nuclear Information System (INIS)

Boeuf, J.P.; Marode, E.; Segur, P.

1984-01-01

The spatio-temporal evolution of an electron swarm under a uniform field has been simulated for a forward/backward scattering model, using a Mac Cormak numerical scheme. Using model cross-sections, the effect of attachment and ionization on the spatial variations of the swarm density and velocity distribution function and on the higher order transport coefficients has been analysed. It is shown that the non uniform spatial distribution of energy within the swarm can induce, for the electron number density, a large deviation from the Gaussian shape. This deviation is due mainly to the fact that ionization is more important in the front of the swarm while attachment prevails in the back of the swarm

Dispersion relation for elastic electron-hydrogen atom forward scattering amplitude

International Nuclear Information System (INIS)

Kuchiev, M.Yu.; Amusia, M.Ya.

1978-01-01

The elastic e+H forward scattering amplitude is an analytical function in the complex energy E plane and has two cuts on the real axis: 0 < E < infinity and -infinity < E < -B, B being the hydrogen ionization potential. The e+H dispersion relation contains two integrals over the right and left cuts. (Auth.)

A measurement of the Q{sup 2}, W and t dependences of deeply virtual Compton scattering at HERA

Energy Technology Data Exchange (ETDEWEB)

Chekanov, S.; Derrick, M.; Magill, S. [Argonne National Lab., Argonne, IL (US)] (and others)

2008-12-15

Deeply virtual Compton scattering, {gamma}{sup *}p{yields}{gamma}p, has been measured in e{sup +}p collisions at HERA with the ZEUS detector using an integrated luminosity of 61.1 pb{sup -1}. Cross sections are presented as a function of the photon virtuality, Q{sup 2}, and photon-proton centre-of-mass energy, W, for a wide region of the phase space, Q{sup 2}>1.5 GeV{sup 2} and 40scattered proton is measured in the leading proton spectrometer, corresponding to an integrated luminosity of 31.3 pb{sup -1}, is used for the first direct measurement of the differential cross section as a function of t, where t is the square of the four-momentum transfer at the proton vertex. (orig.)

Measurement of the Azimuthal Correlation between the most Forward Jet and the Scattered Positron in Deep-Inelastic Scattering at HERA

CERN Document Server

Aaron, F.D.; Andreev, V.; Backovic, S.; Baghdasaryan, A.; Baghdasaryan, S.; Barrelet, E.; Bartel, W.; Begzsuren, K.; Belousov, A.; Belov, P.; Bizot, J.C.; Boudry, V.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Britzger, D.; Bruncko, D.; Bunyatyan, A.; 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.; 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.; Ruiz Tabasco, J.E.; Rusakov, S.; Salek, D.; Sankey, D.P.C.; Sauter, M.; Sauvan, E.; Schmitt, S.; Schoeffel, L.; Schoning, A.; Schultz-Coulon, H.C.; Sefkow, F.; Shtarkov, L.N.; Shushkevich, S.; Sloan, T.; 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.; 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.

2012-03-06

Deep-inelastic positron-proton scattering events at low photon virtuality Q^2 with a forward jet, produced at small angles with respect to the proton beam, are measured with the H1 detector at HERA. A subsample of events with an additional jet in the central region is also studied. For both samples differential cross sections and normalised distributions are measured as a function of the azimuthal angle difference, Delta phi, between the forward jet and the scattered positron. The sensitivity to QCD evolution mechanisms is tested by comparing the data to predictions of Monte Carlo generators based on different evolution approaches as well as to next-to-leading order calculations.

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

International Nuclear Information System (INIS)

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

2011-01-01

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

Calculation of radiative corrections to virtual compton scattering - absolute measurement of the energy of Jefferson Lab. electron beam (hall A) by a magnetic method: arc project

International Nuclear Information System (INIS)

Marchand, D.

1998-11-01

This thesis presents the radiative corrections to the virtual compton scattering and the magnetic method adopted in the Hall A at Jefferson Laboratory, to measure the electrons beam energy with an accuracy of 10 4 . The virtual compton scattering experiments allow the access to the generalised polarizabilities of the protons. The extraction of these polarizabilities is obtained by the experimental and theoretical cross sections comparison. That's why the systematic errors and the radiative effects of the experiments have to be controlled very seriously. In this scope, a whole calculation of the internal radiative corrections has been realised in the framework of the quantum electrodynamic. The method of the dimensional regularisation has been used to the treatment of the ultraviolet and infra-red divergences. The absolute measure method of the energy, takes into account the magnetic deviation, made up of eight identical dipoles. The energy is determined from the deviation angle calculation of the beam and the measure of the magnetic field integral along the deviation

Status of Kharkov X-Ray Generator Based on Compton Scattering NESTOR

Energy Technology Data Exchange (ETDEWEB)

Zelinsky, A.

2005-04-11

Nowadays the sources of the X-rays based on a storage ring with low beam energy and Compton scattering of intense laser beam are under development in several laboratories. In the paper the state-of-art in development and construction of cooperative project of a Kharkov advanced X-ray source NESTOR based on electron storage ring with beam energy 43-225 MeV and Nd:YAG laser is described. The layout of the facility is presented and latest results are described. The designed lattice includes 4 dipole magnets with combined focusing functions, 20 quadrupole magnets and 19 sextupoles with correcting components of magnetic field. At the present time a set of quadrupole magnet is under manufacturing and bending magnet reconstruction is going on. The main parameters of developed vacuum system providing residual gas pressure in the storage ring vacuum chamber up to 10{sup -9} torr are presented. The basic parameters of the X-ray source laser and injection systems are presented. The facility is going to be in operation in the middle of 2006 and generated X-rays flux is expected to be of about 10{sup 13} phot/s.

Laser-electron Compton interaction in plasma channels

International Nuclear Information System (INIS)

Pogorelsky, I.V.; Ben-Zvi, I.; Hirose, T.

1998-10-01

A concept of high intensity femtosecond laser synchrotron source (LSS) is based on Compton backscattering of focused electron and laser beams. The short Rayleigh length of the focused laser beam limits the length of interaction to a few picoseconds. However, the technology of the high repetition rate high-average power picosecond lasers required for high put through LSS applications is not developed yet. Another problem associated with the picosecond laser pulses is undesirable nonlinear effects occurring when the laser photons are concentrated in a short time interval. To avoid the nonlinear Compton scattering, the laser beam has to be split, and the required hard radiation flux is accumulated over a number of consecutive interactions that complicates the LSS design. In order to relieve the technological constraints and achieve a practically feasible high-power laser synchrotron source, the authors propose to confine the laser-electron interaction region in the extended plasma channel. This approach permits to use nanosecond laser pulses instead of the picosecond pulses. That helps to avoid the nonlinear Compton scattering regime and allows to utilize already existing technology of the high-repetition rate TEA CO 2 lasers operating at the atmospheric pressure. They demonstrate the advantages of the channeled LSS approach by the example of the prospective polarized positron source for Japan Linear Collider

Measurement of deeply virtual Compton scattering and its t-dependence at HERA

Energy Technology Data Exchange (ETDEWEB)

Aaron, F.D. [National Insitute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania)]|[Bucharest Univ. (Romania). Faculty of Physics; Aktas, A. [DESY Hamburg (Germany); Alexa, C. [National Insitute for Physics and Nuclear Engineering (NIPNE), Bucharest (RO)] (and others)

2007-09-15

A measurement of elastic deeply virtual Compton scattering {gamma}{sup *}p {yields} {gamma}p using e{sup -}p collision data recorded with the H1 detector at HERA is presented. The analysed data sample corresponds to an integrated luminosity of 145 pb{sup -1}. The cross section is measured as a function of the virtuality Q{sup 2} of the exchanged photon and the centre-of-mass energy W of the {gamma}{sup *}p system in the kinematic domain 6.5

Scaling laws in high-energy inverse compton scattering. II. Effect of bulk motions

International Nuclear Information System (INIS)

Nozawa, Satoshi; Kohyama, Yasuharu; Itoh, Naoki

2010-01-01

We study the inverse Compton scattering of the CMB photons off high-energy nonthermal electrons. We extend the formalism obtained by the previous paper to the case where the electrons have nonzero bulk motions with respect to the CMB frame. Assuming the power-law electron distribution, we find the same scaling law for the probability distribution function P 1,K (s) as P 1 (s) which corresponds to the zero bulk motions, where the peak height and peak position depend only on the power-index parameter. We solved the rate equation analytically. It is found that the spectral intensity function also has the same scaling law. The effect of the bulk motions to the spectral intensity function is found to be small. The present study will be applicable to the analysis of the x-ray and gamma-ray emission models from various astrophysical objects with nonzero bulk motions such as radio galaxies and astrophysical jets.

Virtual Compton scattering and the generalized polarizabilities of the proton at Q²=0.92 and 1.76 GeV²

OpenAIRE

Fonvieille, H; Laveissiere, G; Degrande, N; Jaminion, S; Jutier, C; Todor, L; Di Salvo, R; Van Hoorebeke, Luc; Alexa, LC; Anderson, BD; Aniol, KA; Arundell, K; Audit, G; Auerbach, L; Baker, FT

2012-01-01

Virtual Compton scattering (VCS) on the proton has been studied at the Jefferson Laboratory using the exclusive photon electroproduction reaction ep -> ep gamma. This paper gives a detailed account of the analysis which has led to the determination of the structure functions P-LL - P-TT/epsilon and P-LT and the electric and magnetic generalized polarizabilities (GPs) alpha(E) (Q(2)) and beta(M) (Q(2)) at values of the four-momentum transfer squared Q(2) = 0.92 and 1.76 GeV2. These data, toget...

Analysis on Target Detection and Classification in LTE Based Passive Forward Scattering Radar

Directory of Open Access Journals (Sweden)

Raja Syamsul Azmir Raja Abdullah

2016-09-01

Full Text Available The passive bistatic radar (PBR system can utilize the illuminator of opportunity to enhance radar capability. By utilizing the forward scattering technique and procedure into the specific mode of PBR can provide an improvement in target detection and classification. The system is known as passive Forward Scattering Radar (FSR. The passive FSR system can exploit the peculiar advantage of the enhancement in forward scatter radar cross section (FSRCS for target detection. Thus, the aim of this paper is to show the feasibility of passive FSR for moving target detection and classification by experimental analysis and results. The signal source is coming from the latest technology of 4G Long-Term Evolution (LTE base station. A detailed explanation on the passive FSR receiver circuit, the detection scheme and the classification algorithm are given. In addition, the proposed passive FSR circuit employs the self-mixing technique at the receiver; hence the synchronization signal from the transmitter is not required. The experimental results confirm the passive FSR system’s capability for ground target detection and classification. Furthermore, this paper illustrates the first classification result in the passive FSR system. The great potential in the passive FSR system provides a new research area in passive radar that can be used for diverse remote monitoring applications.

Analysis on Target Detection and Classification in LTE Based Passive Forward Scattering Radar.

Science.gov (United States)

Raja Abdullah, Raja Syamsul Azmir; Abdul Aziz, Noor Hafizah; Abdul Rashid, Nur Emileen; Ahmad Salah, Asem; Hashim, Fazirulhisyam

2016-09-29

The passive bistatic radar (PBR) system can utilize the illuminator of opportunity to enhance radar capability. By utilizing the forward scattering technique and procedure into the specific mode of PBR can provide an improvement in target detection and classification. The system is known as passive Forward Scattering Radar (FSR). The passive FSR system can exploit the peculiar advantage of the enhancement in forward scatter radar cross section (FSRCS) for target detection. Thus, the aim of this paper is to show the feasibility of passive FSR for moving target detection and classification by experimental analysis and results. The signal source is coming from the latest technology of 4G Long-Term Evolution (LTE) base station. A detailed explanation on the passive FSR receiver circuit, the detection scheme and the classification algorithm are given. In addition, the proposed passive FSR circuit employs the self-mixing technique at the receiver; hence the synchronization signal from the transmitter is not required. The experimental results confirm the passive FSR system's capability for ground target detection and classification. Furthermore, this paper illustrates the first classification result in the passive FSR system. The great potential in the passive FSR system provides a new research area in passive radar that can be used for diverse remote monitoring applications.

Measurement of the azimuthal correlation between the most forward jet and the scattered positron 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)

2011-10-15

Deep-inelastic positron-proton scattering events at low photon virtuality Q{sup 2} with a forward jet, produced at small angles with respect to the proton beam, are measured with the H1 detector at HERA. A subsample of events with an additional jet in the central region is also studied. For both samples differential cross sections and normalised distributions are measured as a function of the azimuthal angle difference, {delta}{phi}, between the forward jet and the scattered positron. The sensitivity to QCD evolution mechanisms is tested by comparing the data to predictions of Monte Carlo generators based on different evolution approaches as well as to next-to-leading order calculations. (orig.)

Measurement of the azimuthal correlation between the most forward jet and the scattered positron in deep-inelastic scattering at HERA

International Nuclear Information System (INIS)

Aaron, F.D.; Andreev, V.

2011-10-01

Deep-inelastic positron-proton scattering events at low photon virtuality Q 2 with a forward jet, produced at small angles with respect to the proton beam, are measured with the H1 detector at HERA. A subsample of events with an additional jet in the central region is also studied. For both samples differential cross sections and normalised distributions are measured as a function of the azimuthal angle difference, Δφ, between the forward jet and the scattered positron. The sensitivity to QCD evolution mechanisms is tested by comparing the data to predictions of Monte Carlo generators based on different evolution approaches as well as to next-to-leading order calculations. (orig.)

Crystal Compton Camera

Energy Technology Data Exchange (ETDEWEB)

Ziock, Klaus-Peter [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Braverman, Joshua B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Harrison, Mark J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hornback, Donald Eric [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Fabris, Lorenzo [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Newby, Jason [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2013-09-26

Stand-off detection is one of the most important radiation detection capabilities for arms control and the control of illicit nuclear materials. For long range passive detection one requires a large detector and a means of “seeing through” the naturally occurring and varying background radiation, i.e. imaging. Arguably, Compton imaging is the best approach over much of the emission band suitable for long range detection. It provides not only imaging, but more information about the direction of incidence of each detected gamma-ray than the alternate approach of coded-aperture imaging. The directional information allows one to reduce the background and hence improve the sensitivity of a measurement. However, to make an efficient Compton imager requires localizing and measuring the simultaneous energy depositions when gamma-rays Compton scatter and are subsequently captured within a single, large detector volume. This concept has been demonstrated in semi-conductor detectors (HPGe, CZT, Si) but at ~ $1k/cm³ these materials are too expensive to build the large systems needed for standoff detection. Scintillator detectors, such as NaI(Tl), are two orders of magnitude less expensive and possess the energy resolution required to make such an imager. However, they do not currently have the ability to localize closely spaced, simultaneous energy depositions in a single large crystal. In this project we are applying a new technique that should, for the first time ever, allow cubic-millimeter event localization in a bulk scintillator crystal.

Deeply Virtual Neutrino Scattering

International Nuclear Information System (INIS)

Ales Psaker

2007-01-01

We investigate the extension of the deeply virtual Compton scattering process into the weak interaction sector. Standard electromagnetic Compton scattering provides a unique tool for studying hadrons, which is one of the most fascinating frontiers of modern science. In this process the relevant Compton scattering amplitude probes the hadron structure by means of two quark electromagnetic currents. We argue that replacing one of the currents with the weak interaction current can promise a new insight. The paper is organized as follows. In Sec. II we briefly discuss the features of the handbag factorization scheme. We introduce a new set of phenomenological functions, known as generalized parton distributions (GPDs) [1-6], and discuss some of their basic properties in Sec. III. An application of the GPD formalism to the neutrino-induced deeply virtual Compton scattering in the kinematics relevant to future high-intensity neutrino experiments is given in Sec. IV. The cross section results are presented in Sec. V. Finally, in Sec. VI we draw some conclusions and discuss future prospects. Some of the formal results in this paper have appeared in preliminary reports in Refs. [7] and [8], whereas a comprehensive analysis of the weak neutral and weak charged current DVCS reactions in collaboration with W. Melnitchouk and A. Radyushkin has been presented in Ref. [9

Optimisation of a dual head semiconductor Compton camera using Geant4

Energy Technology Data Exchange (ETDEWEB)

Harkness, L.J. [Department of Physics, University of Liverpool, Oliver Lodge Laboratory, Liverpool L697ZE (United Kingdom)], E-mail: ljh@ns.ph.liv.ac.uk; Boston, A.J.; Boston, H.C.; Cooper, R.J.; Cresswell, J.R.; Grint, A.N.; Nolan, P.J.; Oxley, D.C.; Scraggs, D.P. [Department of Physics, University of Liverpool, Oliver Lodge Laboratory, Liverpool L697ZE (United Kingdom); Beveridge, T.; Gillam, J. [School of Physics and Materials Engineering, Monash University, Melbourne (Australia); Lazarus, I. [STFC Daresbury Laboratory, Warrington, Cheshire (United Kingdom)

2009-06-01

Conventional medical gamma-ray camera systems utilise mechanical collimation to provide information on the position of an incident gamma-ray photon. Systems that use electronic collimation utilising Compton image reconstruction techniques have the potential to offer huge improvements in sensitivity. Position sensitive high purity germanium (HPGe) detector systems are being evaluated as part of a single photon emission computed tomography (SPECT) Compton camera system. Data have been acquired from the orthogonally segmented planar SmartPET detectors, operated in Compton camera mode. The minimum gamma-ray energy which can be imaged by the current system in Compton camera configuration is 244 keV due to the 20 mm thickness of the first scatter detector which causes large gamma-ray absorption. A simulation package for the optimisation of a new semiconductor Compton camera has been developed using the Geant4 toolkit. This paper will show results of preliminary analysis of the validated Geant4 simulation for gamma-ray energies of SPECT, 141 keV.

Deeply virtual Compton scattering with the CLAS detector for the study of generalized parton distributions; Diffusion compton profondement virtuelle avec le detecteur CLAS pour une etude des distributions de partons generalisees

Energy Technology Data Exchange (ETDEWEB)

Girod, F.X

2006-12-15

The structure of the nucleon, among the first fundamental problems in hadronic physics, is the subject of a renewed interest. The lightest baryonic state has historically been described in two complementary approaches: through elastic scattering, measuring form factors which reflect the spatial shape of charge distributions, and through deep inelastic scattering, providing access to parton distribution functions which encode the momentum content carried by the constituents. The recently developed formalism of Generalized Parton Distributions unifies those approaches and provides access to new informations. The cleanest process sensitive to GPDs is the deeply virtual Compton scattering (DVCS) contributing to the ep {yields} ep{gamma} reaction. This work deals with a dedicated experiment accomplished with the CLAS detector, completed with two specific equipments: a lead tungstate calorimeter covering photon detection at small angles, and a superconducting solenoid actively shielding the electromagnetic background. The entire project is covered: from the upgrade of the experimental setup, through the update of the software, data taking and analysis, up to a first comparison of the beam spin asymmetry to model predictions. (author)

Accurate Compton scattering measurements for N{sub 2} molecules

Energy Technology Data Exchange (ETDEWEB)

Kobayashi, Kohjiro [Advanced Technology Research Center, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515 (Japan); Itou, Masayoshi; Tsuji, Naruki; Sakurai, Yoshiharu [Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Hosoya, Tetsuo; Sakurai, Hiroshi, E-mail: sakuraih@gunma-u.ac.jp [Department of Production Science and Technology, Gunma University, 29-1 Hon-cho, Ota, Gunma 373-0057 (Japan)

2011-06-14

The accurate Compton profiles of N{sub 2} gas were measured using 121.7 keV synchrotron x-rays. The present accurate measurement proves the better agreement of the CI (configuration interaction) calculation than the Hartree-Fock calculation and suggests the importance of multi-excitation in the CI calculations for the accuracy of wavefunctions in ground states.

Preliminary Results from Integrating Compton Photon Polarimetry in Hall A of Jefferson Lab

International Nuclear Information System (INIS)

Parno, D; Friend, M; Benmokhtar, F; Franklin, G; Quinn, B; Michaels, R; Nanda, S; Souder, P

2011-01-01

A wide range of nucleon and nuclear structure experiments in Jefferson Lab's Hall A require precise, continuous measurements of the polarization of the electron beam. In our Compton polarimeter, electrons are scattered off photons in a Fabry-Perot cavity; by measuring an asymmetry in the integrated signal of the scattered photons detected in a GSO crystal, we can make non-invasive, continuous measurements of the beam polarization. Our goal is to achieve 1% statistical error within two hours of running. We discuss the design and commissioning of an upgrade to this apparatus, and report preliminary results for experiments conducted at beam energies from 3.5 to 5.9 GeV and photon rates from 5 to 100 kHz.

The Quantum Mechanics of Nano-Confined Water: New Cooperative Effects Revealed with Neutron and X-Ray Compton Scattering

International Nuclear Information System (INIS)

Reiter, G F; Deb, Aniruddha

2014-01-01

Neutron Compton scattering(NCS) measurements of the momentum distribution of light ions using the Vesuvio instrument at ISIS provide a sensitive local probe of the environment of those ions. NCS measurements of the proton momentum distribution in bulk water show only small deviations from the usual picture of water as a collection of molecules, with the protons covalently bonded to an oxygen and interacting weakly, primarily electrostatically, with nearby molecules. However, a series of measurements of the proton momentum distribution in carbon nanotubes, xerogel, and Nafion show that the proton delocalizes over distances of 0.2-0.3Å when water is confined on the scale of 20Å. This delocalization must be the result of changes in the Born-Oppenheimer surface for the protons, which would imply that there are large deviations in the electron distribution from that of a collection of weakly interacting molecules. This has been observed at Spring-8 using x-ray Compton scattering. The observed deviation in the valence electron momentum distribution from that of bulk water is more than an order of magnitude larger than the change observed in bulk water as the water is heated from just above melting to just below boiling. We conclude that the protons and electrons in nano-confined water are in a qualitatively different ground state from that of bulk water. Since the properties of this state persist at room temperature, and the confinement distance necessary to observe it is comparable to the distance between the elements of biological cells, this state presumably plays a role in the functioning of those cells

Methods for assessing forward and backward light scatter in patients with cataract.

Science.gov (United States)

Crnej, Alja; Hirnschall, Nino; Petsoglou, Con; Findl, Oliver

2017-08-01

To compare objective methods for assessing backward and forward light scatter and psychophysical tests in patients with cataracts. Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom. Prospective case series. This study included patients scheduled for cataract surgery. Lens opacities were grouped into predominantly nuclear sclerotic, cortical, posterior subcapsular, and mixed cataracts. Backward light scatter was assessed using a rotating Scheimpflug imaging technique (Pentacam HR), forward light scatter using a straylight meter (C-Quant), and straylight using the double-pass method (Optical Quality Analysis System, point-spread function [PSF] meter). The results were correlated with visual acuity under photopic conditions as well as photopic and mesopic contrast sensitivity. The study comprised 56 eyes of 56 patients. The mean age of the 23 men and 33 women was 71 years (range 48 to 84 years). Two patients were excluded. Of the remaining, 15 patients had predominantly nuclear sclerotic cataracts, 13 had cortical cataracts, 11 had posterior subcapsular cataracts, and 15 had mixed cataracts. Correlations between devices were low. The highest correlation was between PSF meter measurements and Scheimpflug measurements (r = 0.32). The best correlation between corrected distance visual acuity was with the PSF meter (r = 0.45). Forward and backward light-scatter measurements cannot be used interchangeably. Scatter as an aspect of quality of vision was independent of acuity. Measuring forward light scatter with the straylight meter can be a useful additional tool in preoperative decision-making. Copyright © 2017 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Measurement of the azimuthal correlation between the most forward jet and the scattered positron 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, Faculty of Science, Podgorica (ME); Baghdasaryan, A.; Baghdasaryan, S.; Zohrabyan, H. [Yerevan Physics Inst., Yerevan (Armenia); Barrelet, E. [Univ. Pierre et Marie Curie Paris 6, Univ. Denis Diderot Paris 7, CNRS/IN2P3, LPNHE, 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, B.; 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.; Shushkevich, S.; 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 Inst. 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, Kosice (Slovakia)] [and others

2012-03-15

Deep-inelastic positron-proton scattering events at low photon virtuality, Q {sup 2}, with a forward jet, produced at small angles with respect to the proton beam, are measured with the H1 detector at HERA. A subsample of events with an additional jet in the central region is also studied. For both samples, differential cross sections and normalised distributions are measured as a function of the azimuthal angle difference, {delta}{phi}, between the forward jet and the scattered positron in bins of the rapidity distance, Y, between them. The data are compared to predictions of Monte Carlo generators based on different evolution approaches as well as to next-to-leading order calculations in order to test the sensitivity to QCD evolution mechanisms. (orig.)

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

Spin effects in nonlinear Compton scattering in a plane-wave laser pulse

International Nuclear Information System (INIS)

Boca, Madalina; Dinu, Victor; Florescu, Viorica

2012-01-01

We study theoretically the electron angular and energy distribution in the non-linear Compton effect in a finite plane-wave laser pulse. We first present analytical and numerical results for unpolarized electrons (described by a Volkov solution of the Dirac equation), in comparison with those corresponding to a spinless particle (obeying the Klein–Gordon equation). Then, in the spin 1/2 case, we include results for the spin flip probability. The regime in which the spin effects are negligible, i.e. the results for the unpolarized spin 1/2 particle coincide practically with those for the spinless particle, is the same as the regime in which the emitted radiation is well described by classical electrodynamics.

Production of X-rays by inverse Compton effect

International Nuclear Information System (INIS)

Mainardi, R.T.

2005-01-01

X-rays and gamma rays of high energy values can be produced by the scattering of low energy photons with high energy electrons, being this a process controlled by the Compton scattering. If a laser beam is used, the x-ray beam inherits the properties of intensity, monochromaticity and collimation from the laser. In this work we analyze the generation of intense x-ray beams of energies between 10 and 100 KeV to be used in a wide range of applications where a high intensity and high degrees of monochromaticity and polarization are important properties to improve image reduce doses and improve radiation treatments. To this purpose we evaluated, using relativistic kinematics the scattered beam properties in terms of the scattering angle. This arrangement is being considered in several worldwide laboratories as an alternative to synchrotron radiation and is referred to as 'table top synchrotron radiation', since it cost of installation is orders of magnitude smaller than a 'synchrotron radiation source'. The radiation beam might exhibit non-linear properties in its interaction with matter, in a similar way as a laser beam and we will investigate how to calibrate and evaluate TLD dosemeters properties, both in low and high intensity fields either mono or polyenergetic in wide spectral energy ranges. (Author)

Attenuation studies near K-absorption edges using Compton ...

Indian Academy of Sciences (India)

The results are consistent with theoretical values derived from the XCOM package. Keywords. Photon interaction; 241Am; gamma ray attenuation; Compton scattering; absorption edge; rare earth elements. PACS Nos 32.80.-t; 32.90.+a. 1. Introduction. Photon interaction studies at energies around the absorption edge have ...

The scanning Compton polarimeter for the SLD experiment

International Nuclear Information System (INIS)

Woods, M.

1996-10-01

For the 1994/95 run of the SLD experiment at SLAC, a Compton polarimeter measured the luminosity-weighted electron beam polarization to be (77.2 ± 0.5)%. This excellent accuracy is achieved by measuring the rate asymmetry of Compton-scattered electrons near the kinematic endpoint. The polarimeter takes data continuously while the electron and positron beams are in collision and achieves a statistical precision of better than 1% in a three minute run. To calibrate the polarimeter and demonstrate its accuracy, many scans are frequently done. These include scans of the laser polarization, the detector position with respect to the kinematic edge, and the laser power

Compton radiography, 4. Magnification compton radiography

Energy Technology Data Exchange (ETDEWEB)

Okuyama, S; Sera, K; Shishido, F; Fukuda, H [Tohoku Univ., Sendai (Japan). Research Inst. for Tuberculosis and Cancer; Mishina, H

1978-03-01

Compton radiography permits an acquisition of direct magnification Compton radiograms by use of a pinhole collimator, rendering it feasible to overcome the resolution of the scinticamera being employed. An improvement of resolution was attained from 7 mm to 1 mm separation. Usefulness of its clinical application can be seen in orientation of puncture and biopsy in deep structures and detection of various foreign bodies penetrated by blasts and so on under the ''magnification Compton fluoroscopy'' which can be developed on this principle in the near future.

Spin Polarisabilities and Compton Scattering from χEFT: Bridging QCD and Data

Science.gov (United States)

Griesshammer, Harald W.; McGovern, Judith A.; Phillips, Daniel R.

2017-01-01

Compton scattering from protons and neutrons probes their two-photon response in electric and magnetic fields of real photons, exploring the symmetries and interaction strengths of the internal degrees of freedom. With the scalar polarisabilities αE 1 and βM 1 now reasonably understood, the focus turns to the so-far poorly explored spin-polarisabilities. They parametrise the stiffness of the nucleon spin in external electro-magnetic fields, analogous to rotations of the polarisation of light by optically active media (bi-refringence/Faraday effect) and are particularly sensitive to the directional dependence of the πNγ interactions dictated by chiral symmetry and its breaking. This contribution addresses the potential of Chiral Effective Field Theory to relate between lattice QCD and ongoing or approved efforts at MAX-lab, HI γS and MAMI. We discuss high-intensity experiments with polarised targets and polarised beams which will allow the extraction of the spin-polarisabilities; χEFT predictions which indicate which observables for polarised protons, deuterons and 3 He are particularly sensitive; convergence, residual theoretical uncertainties and possibilities for improvement; and chiral extrapolations in mπ for lattice computations. Supported in part by UK STFC, US DOE and George Washington University.

Advanced Laser-Compton Gamma-Ray Sources for Nuclear Materials Detection, Assay and Imaging

Science.gov (United States)

Barty, C. P. J.

2015-10-01

Highly-collimated, polarized, mono-energetic beams of tunable gamma-rays may be created via the optimized Compton scattering of pulsed lasers off of ultra-bright, relativistic electron beams. Above 2 MeV, the peak brilliance of such sources can exceed that of the world's largest synchrotrons by more than 15 orders of magnitude and can enable for the first time the efficient pursuit of nuclear science and applications with photon beams, i.e. Nuclear Photonics. Potential applications are numerous and include isotope-specific nuclear materials management, element-specific medical radiography and radiology, non-destructive, isotope-specific, material assay and imaging, precision spectroscopy of nuclear resonances and photon-induced fission. This review covers activities at the Lawrence Livermore National Laboratory related to the design and optimization of mono-energetic, laser-Compton gamma-ray systems and introduces isotope-specific nuclear materials detection and assay applications enabled by them.

The energy-dependent backward-forward-isotropic scattering model with some applications to the neutron transport equation

International Nuclear Information System (INIS)

Williams, M.M.R.

1985-01-01

A multigroup formalism is developed for the backward-forward-isotropic scattering model of neutron transport. Some exact solutions are obtained in two-group theory for slab and spherical geometry. The results are useful for benchmark problems involving multigroup anisotropic scattering. (author)

Transverse Extension of Partons in the Proton probed by Deeply Virtual Compton Scattering

CERN Document Server

Akhunzyanov, R.; The COMPASS collaboration; Alexeev, G.D.; Amoroso, A.; Andrieux, V.; Anfimov, N.V.; Anosov, V.; Antoshkin, A.; Augsten, K.; Augustyniak, W.; Austregesilo, A.; Azevedo, C.D.R.; Badełek, B.; Balestra, F.; Ball, M.; Barth, J.; Beck, R.; Bedfer, Y.; Bernhard, J.; Bicker, K.; Bielert, E.R.; Birsa, R.; Bodlak, M.; Bordalo, P.; Bradamante, F.; Bressan, A.; Büchele, M.; Burtin, E.; Burtsev, V.E.; Chang, W.-C.; Chatterjee, C.; Chiosso, M.; Choi, I.; Chumakov, A.G.; Chung, S.-U.; Cicuttin, A.; Crespo, M.L.; Dalla Torre, S.; Dasgupta, S.S.; Dasgupta, S.; Denisov, O.Yu.; Dhara, L.; Donskov, S.V.; Doshita, N.; Dreisbach, Ch.; Dünnweber, W.; Dusaev, R.R.; Dziewiecki, M.; Efremov, A.; Eversheim, P.D.; Faessler, M.; Ferrero, A.; Finger, M.; jr., M.Finger; Fischer, H.; Franco, C.; du Fresne von Hohenesche, N.; Friedrich, J.M.; Frolov, V.; Fuchey, E.; Gautheron, F.; Gavrichtchouk, O.P.; Gerassimov, S.; Giarra, J.; Gnesi, I.; Gorzellik, M.; Grasso, A.; Gridin, A.; Grosse Perdekamp, M.; Grube, B.; Grussenmeyer, T.; Guskov, A.; Hahne, D.; Hamar, G.; von Harrach, D.; Heitz, R.; Herrmann, F.; Horikawa, N.; d'Hose, N.; Hsieh, C.-Y.; Huber, S.; Ishimoto, S.; Ivanov, A.; Ivanshin, Yu.; Iwata, T.; Jary, V.; Joosten, R.; Jörg, P.; Juraskova, K.; Kabuß, E.; Kerbizi, A.; Ketzer, B.; Khaustov, G.V.; Khokhlov, Yu.A.; Kisselev, Yu.; Klein, F.; Koivuniemi, J.H.; Kolosov, V.N.; Kondo, K.; Konorov, I.; Konstantinov, V.F.; Kotzinian, A.M.; Kouznetsov, O.M.; Kral, Z.; Krämer, M.; Krinner, F.; Kroumchtein, Z.V.; Kulinich, Y.; Kunne, F.; Kurek, K.; Kurjata, R.P.; Kuznetsov, I.I.; Kveton, A.; Lednev, A.A.; Levchenko, E.A.; Levillain, M.; Levorato, S.; Lian, Y.-S.; Lichtenstadt, J.; Longo, R.; Lyubovitskij, V.E.; Maggiora, A.; Magnon, A.; Makins, N.; Makke, N.; Mallot, G.K.; Mamon, S.A.; Marianski, B.; Martin, A.; Marzec, J.; Matoušek, J.; Matsuda, H.; Matsuda, T.; Meshcheryakov, G.V.; Meyer, M.; Meyer, W.; Mikhailov, Yu.V.; Mikhasenko, M.; Mitrofanov, E.; Mitrofanov, N.; Miyachi, Y.; Moretti, A.; Nagaytsev, A.; Nerling, F.; Neyret, D.; Nový, J.; Nowak, W.-D.; Nukazuka, G.; Nunes, A.S.; Olshevsky, A.G.; Orlov, I.; Ostrick, M.; Panzieri, D.; Parsamyan, B.; Paul, S.; Peng, J.-C.; Pereira, F.; Pešek, M.; Pešková, M.; Peshekhonov, D.V.; Pierre, N.; Platchkov, S.; Pochodzalla, J.; Polyakov, V.A.; Pretz, J.; Quaresma, M.; Quintans, C.; Ramos, S.; Regali, C.; Reicherz, G.; Riedl, C.; Rogacheva, N.S.; Ryabchikov, D.I.; Rybnikov, A.; Rychter, A.; Salac, R.; Samoylenko, V.D.; Sandacz, A.; Santos, C.; Sarkar, S.; Savin, I.A.; Sawada, T.; Sbrizzai, G.; Schiavon, P.; Schmieden, H.; Schönning, K.; Seder, E.; Selyunin, A.; Silva, L.; Sinha, L.; Sirtl, S.; Slunecka, M.; Smolik, J.; Srnka, A.; Steffen, D.; Stolarski, M.; Subrt, O.; Sulc, M.; Suzuki, H.; Szabelski, A.; Szameitat, T.; Sznajder, P.; Tasevsky, M.; Tessaro, S.; Tessarotto, F.; Thiel, A.; Tomsa, J.; Tosello, F.; Tskhay, V.; Uhl, S.; Vasilishin, B.I.; Vauth, A.; Veit, B.M.; Veloso, J.; Vidon, A.; Virius, M.; Wallner, S.; Wilfert, M.; ter Wolbeek, J.; Zaremba, K.; Zavada, P.; Zavertyaev, M.; Zemlyanichkina, E.; Zhuravlev, N.; Ziembicki, M.

2018-01-01

We report on the first measurement of exclusive single-photon muoproduction on the proton by COMPASS using 160 GeV/$c$ polarized $\\mu^+$ and $\\mu^-$ beams of the CERN SPS impinging on a liquid hydrogen target. We determine the dependence of the average of the measured $\\mu^+$ and $\\mu^-$ cross sections for deeply virtual Compton scattering on the squared four-momentum transfer $t$ from the initial to the final final proton. The slope $B$ of the $t$-dependence is fitted with a single exponential function, which yields $B=(4.3 \\ \\pm \\ 0.6_{\\text{stat}}\\ _{- \\ 0.3}^{+ \\ 0.1}\\big\\rvert_{\\text{sys}})\\,(\\text{GeV}/c)^{-2}$. This result can be converted into an average transverse extension of partons in the proton, $\\sqrt{\\langle r_{\\perp}^2 \\rangle} = (0.58 \\ \\pm \\ 0.04_{\\text{stat}}\\ _{- \\ 0.02}^{+ \\ 0.01}\\big\\rvert_{\\text{sys}}) \\text{fm}$. For this measurement, the average virtuality of the photon mediating the interaction is $\\langle Q^2 \\rangle = 1.8\\,(\\text{GeV/}c)^2$ and the average value of the Bjorken va...

Impact picture for near-forward elastic scattering up to LHC energies

CERN Document Server

Soffer, Jacques; Wu, Tai Tsun

2015-01-01

We will recall the main feaatures of an accurate phenomenological model to describe successfully near-forward elastic scattering in a wide energy range, including ISR, SPS and Tevatron colliders. A large step in energy domain is accomplished with the LHC collider, presently running, giving the opportunity to confront the new data with the predictions of our theoretical approach.

Difference in x-ray scattering between metallic and non-metallic liquids due to conduction electrons

International Nuclear Information System (INIS)

Chihara, Junzo

1987-01-01

X-ray scattered intensity from a liquid metal as an electron-ion mixture is described using the structure factors, which are exactly expressed in terms of the static and dynamic direct correlation functions. This intensity for a metal is shown to differ from the usual scattered intensity from a non-metal in two points: the atomic form factor and the incoherent (Compton) scattering factor. It is shown that the valence electron form factor, which constitutes the atomic form factor in a liquid metal, leads to a determination of the electron-electron and electron-ion structure factors by combining the ionic structure factor. It is also shown that a part of the electron structure factor, which appears as the incoherent x-ray scattering, is usually approximated as the electron structure factor of the jellium model in the case of a simple metal. As a by-product, the x-ray scattered intensity from a crystalline metal and the inelastic scattering from a liquid metal are given by taking account of the presence of conduction electrons. In this way, we clarify some confusion which appeared in the proposal by Egelstaff et al for extracting the electron-electron correlation function in a metal from x-ray and neutron scattering experiments. A procedure to extract the electron-electron and electron-ion structure factors in a liquid metal is proposed on the basis of formula for scattered intensity derived here. (author)

Forward optical glory

International Nuclear Information System (INIS)

Nussenzveig, H.M.

Forward optical glory effects in Mie scattering are displayed here for the first time. These effects include regular oscillations in Mie efficiency factors and characteristic deviations from zero polarization in near-forward scattering which are observable for real refractive indices near √2 and 2. Complex angular momentum theory predicts the period of oscillation correctly and shows the important role played by surface waves with shortcuts through the sphere. three possible types of experiments for detecting the forward glory are proposed, involving measurements of extinction, radiation pressure, and polarization in near-forward scattering. (Author) [pt

Development of a Compton camera for online monitoring and dosimetry of laser-accelerated proton beams

Energy Technology Data Exchange (ETDEWEB)

Thirolf, Peter G.; Lang, Christian; Aldawood, Saad; Parodi, Katia [LMU Muenchen (Germany); Habs, Dietrich [LMU Muenchen (Germany); MPI fuer Quantenoptik, Garching (Germany); Maier, Ludwig [TU Muenchen (Germany)

2013-07-01

A Compton camera is presently under construction in Garching, designed for monitoring and dosimetry of laser-accelerated protons for bio-medical applications via position-resolved prompt γ-ray detection. When ion beams suitable for hadron therapy (protons, carbon ions) interact with tissue (or tissue-equivalent plastic or water phantoms), nuclear reactions induce prompt γ rays that can be utilized, e.g., to verify the ion beam range (i.e. monitor the Bragg peak position) by exploiting the Compton scattering kinematics of these photons. Our Compton camera (formed by a combination of scatter and absorber detector) consists of a stack of six double-sided Si-strip detectors (50 x 50 mm{sup 2}, 0.5 mm thick, 128 strips/side, pitch 390 μm) acting as scatterers, while the absorber is formed by a LaBr{sub 3} scintillator crystal (50 x 50 x 30 mm{sup 3}), read out by a (8 x 8) pixelated multi-anode PMT. Simulation results for design specifications and expected values of resolution and efficiency are presented, as well as the status of the prototype presently under construction.

Deeply virtual Compton scattering off longitudinally polarised protons at HERMES

International Nuclear Information System (INIS)

Mahon, David Francis

2010-03-01

This thesis details the simultaneous extraction of three polarisation-dependent asymmetries in the distribution of real photons from the ep→epγ interaction and its indistinguishable deeply virtual Compton scattering and Bethe-Heitler processes at the HERMES fixed-target experiment at Desy. The data analysed were taken using a longitudinally polarised 27.57 GeV positron beam incident on a longitudinally polarised hydrogen gas target. The extracted asymmetries include two single-spin asymmetries A UL and A LU which depend on the polarisation of the target and beam respectively, averaged over all other polarisation states. The double-spin asymmetry A LL dependent on the product of the beam and target polarisations is extracted for the first time. The asymmetry amplitudes extracted relate to combinations of Generalised Parton Distributions (GPDs), predominantly H and H. The extracted amplitudes are presented across the HERMES kinematic range alongside theoretical predictions from a GPD model based on double distributions. Large sin φ and cos(0φ) amplitudes are observed for A UL and A LL respectively, with an unexpectedly large sin(2φ) amplitude for A UL . The results for the A UL and A LL asymmetries are broadly compatible with theory predictions, and the extracted A LU amplitudes are compatible with HERMES results extracted from a significantly larger data set. It is foreseen that these results will form input to future global data-based GPD models which aim to provide a better understanding of GPDs. (orig.)

Analytical structure of the 3. -->. 3 forward scattering amplitude

Energy Technology Data Exchange (ETDEWEB)

Logunov, A A; Medvedev, B V; Muzafarov, L M; Pavlov, V P; Polivanov, M K; Sukhanov, A D [AN SSSR, Moscow. Matematicheskij Inst.

1979-08-01

Analytical properties of the amplitude of 3..-->..3 forward scattering established in the framework of the Bogolyubov axiomatic approach are described. The amplitudes of the different channels of the process are boundary values of a unique analytical function of invariant variables. Crossing-symmetry property of the amplitude is proved. Analysis of the absorptive part of the amplitude is performed and the generalized optical theorem is proved which connects one of the contributions into the absorptive part with the distribution function of the inclusive process.

X-ray dosimetry in mammography for W/Mo and Mo/Mo combinations utilizing Compton spectrometry

International Nuclear Information System (INIS)

Almeida Junior, Jose N.; Terini, Ricardo A.; Herdade, Silvio B.; Furquim, Tania A.C.

2009-01-01

Mean Glandular Dose (MGD) cannot be measured directly in mammography equipment. Therefore, methods based on Compton spectrometry are alternatives to evaluate dose distributions in a standard breast phantom, as well as mean glandular dose. In this work, a CdTe detector was used for the spectrometry measurements of radiation scattered by compton effect, at nearly 90, by a PMMA cylinder. For this, the reconstruction of primary beam spectra from the scattered ones has been made using Klein-Nishina theory and Compton formalism, followed by a determination of incident air kerma, absorbed dose values in the breast phantom and, finally, MGD. Incident and attenuated X-ray spectra and depth-dose distributions in a BR-12 phantom have been determined and are presented for the mammography range (28 to 35kV), showing good agreement with previous literature data, obtained with TLD. (author)

Invertible propagator for plane wave illumination of forward-scattering structures.

Science.gov (United States)

Samelsohn, Gregory

2017-05-10

Propagation of directed waves in forward-scattering media is considered. It is assumed that the evolution of the wave field is governed by the standard parabolic wave equation. An efficient one-step momentum-space propagator, suitable for a tilted plane wave illumination of extended objects, is derived. It is expressed in terms of a propagation operator that transforms (the complex exponential of) a linogram of the illuminated object into a set of its diffraction patterns. The invertibility of the propagator is demonstrated, which permits a multiple-shot scatter correction to be performed, and makes the solution especially attractive for either projective or tomographic imaging. As an example, high-resolution tomograms are obtained in numerical simulations implemented for a synthetic phantom, with both refractive and absorptive inclusions.

Forward scattering of polarized light from a turbid slab: theory and Monte Carlo simulations.

Science.gov (United States)

Otsuki, Soichi

2016-12-20

It is proved that if reciprocity and mirror symmetry hold for single scattering by a particle, they also hold for multiple scattering in turbid slab media. Monte Carlo simulations generate a reduced effective Mueller matrix for forward scattering, which satisfies reciprocity and mirror symmetry, but satisfies only reciprocity if the medium contains chiral components. The scattering matrix was factorized by using the Lu-Chipman polar decomposition, which affords the polarization parameters as a function of the radial distance from the center. The depolarization coefficients decrease with increasing distance, whereas the scattering-induced linear diattenuation and retardance become larger in the middle-distance range. The optical rotation for a chiral medium increases with increasing distance.

WE-DE-207B-12: Scatter Correction for Dedicated Cone Beam Breast CT Based On a Forward Projection Model

Energy Technology Data Exchange (ETDEWEB)

Shi, L; Zhu, L [Georgia Institute of Technology, Atlanta, GA (Georgia); Vedantham, S; Karellas, A [University of Massachusetts Medical School, Worcester, MA (United States)

2016-06-15

Purpose: The image quality of dedicated cone-beam breast CT (CBBCT) is fundamentally limited by substantial x-ray scatter contamination, resulting in cupping artifacts and contrast-loss in reconstructed images. Such effects obscure the visibility of soft-tissue lesions and calcifications, which hinders breast cancer detection and diagnosis. In this work, we propose to suppress x-ray scatter in CBBCT images using a deterministic forward projection model. Method: We first use the 1st-pass FDK-reconstructed CBBCT images to segment fibroglandular and adipose tissue. Attenuation coefficients are assigned to the two tissues based on the x-ray spectrum used for imaging acquisition, and is forward projected to simulate scatter-free primary projections. We estimate the scatter by subtracting the simulated primary projection from the measured projection, and then the resultant scatter map is further refined by a Fourier-domain fitting algorithm after discarding untrusted scatter information. The final scatter estimate is subtracted from the measured projection for effective scatter correction. In our implementation, the proposed scatter correction takes 0.5 seconds for each projection. The method was evaluated using the overall image spatial non-uniformity (SNU) metric and the contrast-to-noise ratio (CNR) with 5 clinical datasets of BI-RADS 4/5 subjects. Results: For the 5 clinical datasets, our method reduced the SNU from 7.79% to 1.68% in coronal view and from 6.71% to 3.20% in sagittal view. The average CNR is improved by a factor of 1.38 in coronal view and 1.26 in sagittal view. Conclusion: The proposed scatter correction approach requires no additional scans or prior images and uses a deterministic model for efficient calculation. Evaluation with clinical datasets demonstrates the feasibility and stability of the method. These features are attractive for clinical CBBCT and make our method distinct from other approaches. Supported partly by NIH R21EB019597, R21CA134128

Compton suppression system at Penn State Radiation Science and Engineering Center

International Nuclear Information System (INIS)

Cetiner, N.Oe.; Uenlue, K.; Brenizer, J.S.

2008-01-01

A Compton suppression system is used to reduce the contribution of scattered gamma-rays that originate within the HPGe detector to the gamma ray spectrum. The HPGe detector is surrounded by an assembly of guard detectors, usually NaI(Tl). The HPGe and NaI(Tl) detectors are operated in anti-coincidence mode. The NaI(Tl) guard detector detects the photons that Compton scatter within, and subsequently escape from the HPGe detector. Since these photons are correlated with the partial energy deposition within the detector, much of the resulting Compton continuum can be subtracted from the spectrum reducing the unwanted background in gamma-ray spectra. A commercially available Compton suppression spectrometer (CSS) was purchased from Canberra Industries and tested at the Radiation Science and Engineering Center at Penn State University. The PSU-CSS includes a reverse bias HPGe detector, four annulus NaI(Tl) detectors, a NaI(Tl) plug detector, detector shields, data acquisition electronics, and a data processing computer. The HPGe detector is n-type with 54% relative efficiency. The guard detectors form an annulus with 9-inch diameter and 9-inch height, and have a plug detector that goes into/out of the annulus with the help of a special lift apparatus to raise/lower. The detector assembly is placed in a shielding cave. State-of-the-art electronics and software are used. The system was tested using standard sources, neutron activated NIST SRM sample and Dendrochronologically Dated Tree Ring samples. The PSU-CSS dramatically improved the peak-to-Compton ratio, up to 1000 : 1 for the 137 Cs source. (author)

Hanle effect at forward scattering in excited media

International Nuclear Information System (INIS)

Veklenko, B.A.

2001-01-01

One introduces a new method to calculate matrix of density of quantized electromagnetic field interacting with environment with kinetic processes in the medium. This method alongside with the accurate account of photon-photon quantum correlators has a number of symmetry features essentially facilitating summing up of appearing Feynman diagrams. Forward scattering of resonance radiation by gas two-level atoms within magnetic field was studied as a supplement. It is shown that inadequacy of semiclassical description of this coherent process in the excited media using unique tensor factor of refraction follows from quantum electrodynamics. One more function depending on frequency of irradiation and on concentration of excited atoms should be introduced [ru

Asymmetry and the shift of the Compton profile

International Nuclear Information System (INIS)

Chatterjee, B.K.; Roy, S.C.; Suric, T.; LaJohn, L.A.; Pratt, R.H.

2007-01-01

We show that the conventionally defined asymmetry of the Compton profile (CP) is, to a large extent, simply a shift of CP. Compton scattering is widely used in studying the electron momentum distribution (EMD) of complex systems. Extraction of information about the EMD is based on an impulse approximation (IA) description of the process. In IA the scattering from bound electrons is described as scattering from the EMD of free electrons. Most often the angular and energy distributions of scattered photons (doubly differential cross sections (DDCS)) is measured and presented in terms of CP, which is just the DDCS normalized by a kinematical factor. The deviations of measured CP from the IA results are conventionally described as an asymmetry of CP about the IA peak position. IA predicts CP to be symmetric. We have examined the discrepancy between IA predictions (and the corresponding relativistic version of IA, RIA) and more rigorous approaches (A 2 and S-matrix), using independent particle approximations for the description of the bound state of electrons. In the nonrelativistic region (in which many measurements of CP are performed) we find that the conventional asymmetry can largely be understood as the shift of the peak position. The true asymmetry with respect to the shifted peak position is in fact much smaller. RIA has similar properties to IA, except that for atoms with high nuclear charge the p → .A → interaction may modify the shift and limit the utility of description as a shift

Soliton Compton Mass from Auto-Parametric Wave-Soliton Coupling

CERN Document Server

Binder, B

2002-01-01

In this paper a self-excited Rayleigh-type system models the auto-parametric wave-soliton coupling via phase fluctuations. The parameter of dissipative terms determine not only the most likely quantum coupling between solitons and linear waves but also the most likely mass of the solitons. Phase fluctuations are mediated by virtual photons coupling at light-velocity in a permanent Compton scattering process. With a reference to the SI-units and proper scaling relations in length and velocity, the final result shows a highly interesting sequence: the likely soliton Compton mass is about 1.00138 times the neutron and 1.00276 times the proton mass.

Main Achievements 2003-2004 - Condensed Matter Studies - Electronic structure of disordered alloys studied by Compton scattering

International Nuclear Information System (INIS)

2005-01-01

3D momentum density and the Fermi surface of disordered Cu 0.86 Al 0.16 alloy were reconstructed from high-resolution Compton profiles. The effect known as ''nesting'' of the Fermi surface was revealed (cooperation with KEK, Tsukuba, Japan). This feature of the Fermi surface, when present, is believed to lead to local ordering phenomena in disordered systems. Our electron diffraction studies showed that a short-range order was indeed present in the alloy. Moreover, the character of the diffuse scattering (the four-fold splitting of the diffuse spots) pointed to the ''nesting'' of the Fermi surface as the origin of this ordering. The results lend support to the notion that the formation of the short-range order in nondiluted, disordered alloys can be driven by their electronic properties like the shape of the Fermi surface

A stacked CdTe pixel detector for a compton camera

International Nuclear Information System (INIS)

Oonuki, Kousuke; Tanaka, Takaaki; Watanabe, Shin; Takeda, Shin'ichiro; Nakazawa, Kazuhiro; Ushio, Masayoshi; Mitani, Takefumi; Takahashi, Tadayuki; Tajima, Hiroyasu

2007-01-01

We are developing a semiconductor Compton telescope to explore the universe in the energy band from several tens of keV to a few MeV. A detector material of combined Si strip and CdTe pixel is used to cover the energy range around 60keV. For energies above several hundred keV, in contrast, the higher detection efficiency of CdTe semiconductor in comparison with Si is expected to play an important role as both an absorber and a scatterer. In order to demonstrate the spectral and imaging capability of a CdTe-based Compton camera, we developed a Compton telescope consisting of a stack of CdTe pixel detectors as a small scale prototype. With this prototype, we succeeded in reconstructing images and spectra by solving the Compton kinematics within the energy band from 122 to 662keV. The energy resolution (FWHM) of reconstructed spectra is 7.3keV at 511keV. The angular resolution obtained at 511keV is measured to be 12.2 deg. (FWHM)

Quantitative impact of small angle forward scatter on whole blood oximetry using a Beer-Lambert absorbance model.

Science.gov (United States)

LeBlanc, Serge Emile; Atanya, Monica; Burns, Kevin; Munger, Rejean

2011-04-21

It is well known that red blood cell scattering has an impact on whole blood oximetry as well as in vivo retinal oxygen saturation measurements. The goal of this study was to quantify the impact of small angle forward scatter on whole blood oximetry for scattering angles found in retinal oximetry light paths. Transmittance spectra of whole blood were measured in two different experimental setups: one that included small angle scatter in the transmitted signal and one that measured the transmitted signal only, at absorbance path lengths of 25, 50, 100, 250 and 500 µm. Oxygen saturation was determined by multiple linear regression in the 520-600 nm wavelength range and compared between path lengths and experimental setups. Mean calculated oxygen saturation differences between setups were greater than 10% at every absorbance path length. The deviations to the Beer-Lambert absorbance model had different spectral dependences between experimental setups, with the highest deviations found in the 520-540 nm range when scatter was added to the transmitted signal. These results are consistent with other models of forward scatter that predict different spectral dependences of the red blood cell scattering cross-section and haemoglobin extinction coefficients in this wavelength range.

Optically controlled seeding of Raman forward scattering and injection of electrons in a self-modulated laser-wakefield accelerator

International Nuclear Information System (INIS)

Chen, W.-T.; Chien, T.-Y.; Lee, C.-H.; Lin, J.-Y.; Wang, J.; Chen, S.-Y.

2004-01-01

Optical seeding of plasma waves and the injection of electrons are key issues in self-modulated laser-wakefield accelerators. By implementing a copropagating laser prepulse with proper timing, we are able to control the growth of Raman forward scattering and the production of accelerated electrons. The dependence of the Raman intensity on prepulse timing indicates that the seeding of Raman forward scattering is dominated by the ionization-induced wakefield, and the dependence of the divergence and number of accelerated electrons further reveals that the stimulated Raman backward scattering of the prepulse plays the essential role of injecting hot electrons into the fast plasma wave driven by the main pulse

Final state effects in neutron Compton scattering measurements

International Nuclear Information System (INIS)

Fielding, A.L.

1997-10-01

The single atom momentum distributions of condensed matter systems can be derived using the technique of neutron Compton scattering (NCS). The electron Volt spectrometer (eVS) which is situated at the world's most intense pulsed neutron spallation source, ISIS, has been configured to perform NCS measurements. Interpretation of NCS data requires the use of the impulse approximation, however even at the high energy and momentum transfers obtainable on the eVS deviations from the impulse approximation occur. These deviations are generally known as final state effects (FSE) which manifest themselves as an asymmetry in the measured momentum distribution. The aim of the work reported in this thesis is to demonstrate how final state effects can be accounted for in a simple way using the expansion method described by Sears. An advantage of the Sears method is that the first asymmetric term in the expansion is proportional to the mean Laplacian of the potential, 2 V>, thus giving access to further information on the single atom potential. The Sears expansion has been incorporated into data analysis routines and applied to measured data on three systems that were chosen to represent the systems that are regularly investigated using the eVS. Measurements have been carried out on the deuteron in ZrD 2 , a light atom in a heavy lattice, beryllium, a polycrystalline solid and pyrolytic graphite, an aligned crystalline sample with an anisotropic momentum distribution. The study shows how the new analysis method gives more reliable values for the mean kinetic energy k >, which can be derived from the measured momentum distribution. A comparison of measured data with simulated data calculated within the harmonic approximation reveals how 2 V> can be a sensitive probe of anharmonicity of the interatomic potential. An anisotropy in the derived k > and 2 V> of pyrolytic graphite has been measured indicating the dependence of final state effects on bonding strength. The derived 2 V

Deeply virtual Compton scattering off longitudinally polarised protons at HERMES

Energy Technology Data Exchange (ETDEWEB)

Mahon, David Francis

2010-06-15

This thesis details the simultaneous extraction of three polarisation-dependent asymmetries in the distribution of real photons from the ep{yields}ep{gamma} interaction and its indistinguishable deeply virtual Compton scattering and Bethe-Heitler processes at the HERMES fixed-target experiment at Desy. The data analysed were taken using a longitudinally polarised 27.57 GeV positron beam incident on a longitudinally polarised hydrogen gas target. The extracted asymmetries include two single-spin asymmetries A{sub UL} and A{sub LU} which depend on the polarisation of the target and beam respectively, averaged over all other polarisation states. The double-spin asymmetry A{sub LL} dependent on the product of the beam and target polarisations is extracted for the first time. The asymmetry amplitudes extracted relate to combinations of Generalised Parton Distributions (GPDs), predominantly H and H. The extracted amplitudes are presented across the HERMES kinematic range alongside theoretical predictions from a GPD model based on double distributions. Large sin {phi} and cos(0{phi}) amplitudes are observed for A{sub UL} and A{sub LL} respectively, with an unexpectedly large sin(2{phi}) amplitude for A{sub UL}. The results for the A{sub UL} and A{sub LL} asymmetries are broadly compatible with theory predictions, and the extracted A{sub LU} amplitudes are compatible with HERMES results extracted from a significantly larger data set. It is foreseen that these results will form input to future global data-based GPD models which aim to provide a better understanding of GPDs. (orig.)

Investigation of Compton effect on π-meson and charged pion polarizability

International Nuclear Information System (INIS)

Antipov, Yu.M.; Batarin, V.A.; Bezzubov, V.A.

1986-01-01

The results of an experiment aimed at the study of the 40 GeV/c pion radiative scattering on nuclei at small momentum transfers are presented. Compton effect on the pion was investigated and the charged pion polarizability was measured. The pion Compton-effect cross section dependence on the incident photon energy ω' 1 (rest pion frame) was measured in the 100 - 600 MeV range. The polarizability of charged pion from the analysis of Compton-effect events has been found to be β π =-α π =(-6.9 ± 1.4 stat. ± 1.2 syst. )x10 -43 cm 3 and the sun of pion electrical α π and magnetic β π polarizability has been estimated to be in agreement with theoretical predictions: α π +β π ≅ 0

Poster — Thur Eve — 01: The effect of the number of projections on MTF and CNR in Compton scatter tomography

International Nuclear Information System (INIS)

Chighvinadze, T; Pistorius, S

2014-01-01

Purpose: To investigate the dependence of the reconstructed image quality on the number of projections in multi-projection Compton scatter tomography (MPCST). The conventional relationship between the projection number used for reconstruction and reconstructed image quality pertained to CT does not necessarily apply to MPCST, which can produce images from a single projection if the detectors have sufficiently high energy and spatial resolution. Methods: The electron density image was obtained using filtered-backprojection of the scatter signal over circular arcs formed using Compton equation. The behavior of the reconstructed image quality as a function of the projection number was evaluated through analytical simulations and characterized by CNR and MTF. Results: The increase of the projection number improves the contrast with this dependence being a function of fluence. The number of projections required to approach the asymptotic maximum contrast decreases as the fluence increases. Increasing projection number increases the CNR but not spatial resolution. Conclusions: For MPCST using a 500eV energy resolution and a 2×2mm 2 size detector, an adequate image quality can be obtained with a small number of projections provided the incident fluence is high enough. This is conceptually different from conventional CT where a minimum number of projections is required to obtain an adequate image quality. While increasing projection number, even for the lowest dose value, the CNR increases even though the number of photons per projection decreases. The spatial resolution of the image is improved by increasing the sampling within a projection rather than by increasing the number of projections

A new method of explosive detection based on dual-energy X-ray technology and forward-scattering

International Nuclear Information System (INIS)

Zhao Kun; Li Jianmin

2004-01-01

Based on dual-energy X-ray technology combined with forward-scattering, a brand new explosive detection method is presented. Dual-energy technology can give the information on the effective atomic number (Z eff ) of an irradiated component, while the intensity of the forward scattered photons can reveal the density information according to our research. Therefore, the existence of the explosive can be effectively identified by combining these two characteristic quantities. Compared with the earlier inspection approaches, the new one has a series of particular advantages, such as high detection rate, low false alarm rate, automatic alarm and so forth. The project is ongoing. (authors)

Neutron angular distribution in (γ, n reactions with linearly polarized γ-ray beam generated by laser Compton scattering

Directory of Open Access Journals (Sweden)

K. Horikawa

2014-10-01

Full Text Available In 1957, Agodi predicted that the neutron angular distribution in (γ, n reactions with a 100% linearly polarized γ-ray beam for dipole excitation should be anisotropic and universally described by the simple function of a+b⋅cos⁡(2ϕ at the polar angle θ=90°, where ϕ is the azimuthal angle. However, this prediction has not been experimentally confirmed in over half a century. We have verified experimentally this angular distribution in the (γ, n reaction for 197Au, 127I, and natural Cu targets using linearly polarized laser Compton scattering γ-rays. The result suggests that the (γ→, n reaction is a novel tool to study nuclear physics in the giant dipole resonance region.

Methodology for obtaining a solution for the three-dimensional Boltzmann transport equation and an expression for the calculation of the total doses considering Compton scattering simulated by Klein-Nishina

International Nuclear Information System (INIS)