The absolute double-differential Compton scattering cross section of Cu 1s electrons

Laukkanen, J.; Hämäläinen, K.; Manninen, S.

doi:10.1088/0953-8984/8/13/007

Cited by 10 publications

(4 citation statements)

References 20 publications

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“…At these energies it is known that ISF is not good due to the neglect of dynamic scattering term while the perturbative method used to obtain ''best'' predictions at lower energies may not be completely adequate, both because the various perturbations become large and because they are not necessarily independent. Ribberfors (1975b): light dashed lines; nonrelativistic impulse approximation: crosses with error bars; measured double differential cross sections of Laukkanen et al (1996). discussions. The manuscript was prepared under the auspices of Indo-US cooperative project ''Investigations on theoretical aspects of Compton scattering'' supported jointly by the Department of Science and Technology, Govt.…”

Section: Resultsmentioning

confidence: 99%

“…Solid symbols represent measurements using synchrotron sources and hollow symbols represent measurements with conventional sources (Source: Roy and Pratt, 2004). noticeable feature is that measured cross sections (using conventional sources) for lighter elements (up to copper here) are, in general, found to be larger than the ISF values while those for relatively heavier elements are less than the ISF. It may be mentioned that use of synchrotron sources, particularly in coincidence experiments, has been is seriously questioned due to the high random coincidence rate due to the pulsed nature of the beam (Laukkanen et al, 1996).…”

Section: Difference Between Isf and 'Best'mentioning

confidence: 99%

“…Results have been compared with the non-relativistic and relativistic IAs and with the experimental results of Laukkanen et al (1996) in Fig. 8.…”

Section: Difference Between Isf and 'Best'mentioning

confidence: 99%

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Investigations on compton scattering: New directions

Chatterjee¹,

LaJohn²,

Roy³

2006

Radiation Physics and Chemistry

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Section: Resultsmentioning

confidence: 99%

Section: Difference Between Isf and 'Best'mentioning

confidence: 99%

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Investigations on compton scattering: New directions

Chatterjee¹,

LaJohn²,

Roy³

2006

Radiation Physics and Chemistry

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“…Some examples of applications of this theory to the prediction of Compton DDCS of light atoms in nonrelativistic (nr) regimes are found in Refs. [1][2][3]. The nonrelativistic theory, which is what the IA approach was originally based on, starts with a two-term interaction Hamiltonian H int = (e 2 A 2 /2m 2 ) − e( p · A)/m.…”

Section: Introductionmentioning

confidence: 99%

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

LaJohn¹

2010

Phys. Rev. A

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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 p i is not too high, that is, p i < m. This corresponds to a binding energy E b < 10 keV. This q → 0 nr limit is simultaneous with the approach of the scattering angle θ to 0 • (θ → 0 • ) around the Compton peak maximum. This explains the observation that it is possible to obtain an accurate Compton peak (CP) even when ω 1 > m using nr expressions when θ is small. For example, a 1% accuracy can be obtained when ω 1 = 1 MeV if θ < 20 • . However as ω 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 • when ω 1 < 300 keV, begins to decrease, approaching zero even though the θ at which the relativistic increase in the CP magnitude remains greatest around θ = 180 • . The relativistic contribution to the prediction of Compton doubly differential cross sections (DDCS) is characterized in simple terms using Ribberfors further approximation to his full RIA expression. This factorable form is given by DDCS = KJ , where K is the kinematic factor and J the Compton profile. This form makes it possible to account for the relativistic shift of CP to higher energy and the increase in the CP magnitude as being due to the dependence of J (p 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. L. A. LAJOHNPHYSICAL REVIEW A 81, 043404 (2010) taking the nr limit of the second-order perturbation relativistic QED S-matrix element to obtain expressions for DDCS and triply differential cross sections (TDCS), free of spurious singularities but having a separable A 2 and p · A form (not separable in the fully relativistic S-matrix expression). He then introduced relativistic kinematics, resulting in expressions that can be used to obtain reasonably accurate K-shell DDCS at all θ if ω 1 < 300 keV. At higher energies this expression only works at smaller scattering angles. This was illustrated by their example calculation in which ω 1 = 661 keV and θ 60 • .In NRIA theory, DDCS are proportional to the Compton profile, given bywhere p is the initial electron momentum. ρ nr (p) is the Fourier transform of the nr charge density ρ nr (r)...

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Compton scattering of 59.54 keV γ‐rays from Fe and p‐Si samples in an external magnetic field

Şahin

Demir

2003

X-Ray Spectrometry

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We report on the Compton scattering of photons from samples whose surface charge density distributions are changed by an external magnetic field. We performed a Compton scattering experiment known to be particularly sensitive to the behavior of the relatively slower moving outer electrons (valence electrons) involved in bonding in condensed matter. The external magnetic field was used to change the surface charge density distributions of Fe and p‐Si samples. Samples were located in the external magnetic field of intensity 215 G and in a direction which was perpendicular both to the current and surface of the samples bombarded by 59.5 keV γ‐photons emitted from an Am‐241 point source. Currents in the ranges 0–8.5 A and 0–300 µA were applied to the Fe and p‐Si samples, respectively. The Compton scattered photons at an angle of 100° were detected by an Si(Li) detector. It was observed that the counts acquired under the Compton peaks tended to decrease linearly with increasing current in a magnetic field. The results show that positive charge carriers behave like negative charge carriers and electrons are more effective than holes in the Compton scattering of γ‐rays. Copyright © 2003 John Wiley & Sons, Ltd.

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The absolute double-differential Compton scattering cross section of Cu 1s electrons

Cited by 10 publications

References 20 publications

Investigations on compton scattering: New directions

Investigations on compton scattering: New directions

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

Compton scattering of 59.54 keV γ‐rays from Fe and p‐Si samples in an external magnetic field

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