Cherenkov radiation of e
                    <sup>+</sup>
                    e
                    <sup>−</sup>
                    pairs and its application for the measurement of gamma-quanta beam polarization

Gevorgian, Lekdar; Ispirian, K.A.; Ispirian, M.K.; Piuz, F.

doi:10.1209/epl/i1996-00436-6

Cited by 6 publications

(11 citation statements)

References 10 publications

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“…The zero azimuthal harmonic (s = 0) in expansion (2.9) corresponds to the continuum potential of a nanotube averaged over the azimuthal angle [47,50]. The remaining harmonics lead to an azimuthal modulation of the potential.…”

Section: The Nanotube Continuum Potentialmentioning

confidence: 99%

“…However their calculations were based on quite unrealistic model for the continuum potential which lead the authors to some erroneous conclusions. Then Gevorgian and Ispirian [47,49] made estimates of channeling properties of nanotubes using more realistic continuum potential. Their works stimulated more systematic theoretical investigations of channeling and associated phenomena in nanocrystals based on the most accurate continuum potential [46] discussed above.…”

Section: Channeling Of Positively and Negatively Charged Particles In Nanocrystalsmentioning

confidence: 99%

“…Here min , max are the perihelion and aphelion of the orbit and is the precession (nutation) angle. Further analytical calculations, giving a qualitative picture of channeling, are possible with simplified expression for U( ) [46,47]. It is important to note that the electric field of a nanotube is strong enough only in the vicinity of the wall, the bottom of the potential well for a positive particle being nearly flat (Fig.…”

Section: Classical Channeling Of Ultra-relativistic Electrons and Positrons And Of Ions In Straight Nanocrystalsmentioning

confidence: 99%

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Carbon nanotubes and fullerites in high-energy and X-ray physics

et al. 2005

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It is demonstrated that the unique structures of carbon nanotubes and single-crystals of C 60 fullerenes may have applications to X-ray, neutron and high-energy particle physics, based on channeling, Bragg diffraction and coherent radiation. These are reviewed, pointing out the peculiarities and advantages of nanocrystals compared to ordinary crystals. New applications are explored: X-rays and neutron channeling, undulator radiation in periodically bent nanotubes, "channeled" transition radiation. Quantum and classical channeling, channeling in bent nanocrystals, Bragg scattering of X-rays and neutrons, chan neling radiation, coherent bremsstrahlung, parametric X-ray and nanotube undulator radiation are particularly studied using both analytical and Monte-Carlo methods. Continuous potentials, electron densities, transverse energy levels, and spectra of various types of coherent radiation are calcu-lated. Large dechanneling lengths of positive particles, bending efficiencies, reflecting coefficients of soft X-rays and PXR yields are predicted. Principles of particle detectors using photo-and secondary electron emissions are discussed.

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Section: The Nanotube Continuum Potentialmentioning

confidence: 99%

Section: Channeling Of Positively and Negatively Charged Particles In Nanocrystalsmentioning

confidence: 99%

Section: Classical Channeling Of Ultra-relativistic Electrons and Positrons And Of Ions In Straight Nanocrystalsmentioning

confidence: 99%

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Carbon nanotubes and fullerites in high-energy and X-ray physics

et al. 2005

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“…A closely related effect -both to the density effect [6, 13.5] and the KPC effect -has been calculated for Cherenkov radiation emission from e þ e À pairs in the vicinity of the creation point [7,8]. This internal screening effect may affect decisively the behaviour of the Cherenkov emission in neutrino-induced electromagnetic showers.…”

Section: Introductionmentioning

confidence: 96%

Measurements and theories of the King–Perkins–Chudakov effect

Thomsen

Uggerhøj

2011

Nuclear Instruments and Methods in Physics Research Section B:

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“…13.5) and the Chudakov effect-has recently been calculated for Cherenkov radiation emission from e e ÿ pairs in the vicinity of the creation point [5,6]. This internal screening effect may affect decisively the behavior of the Cherenkov emission in neutrino-induced electromagnetic showers.…”

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confidence: 96%

Direct Measurement of the Chudakov Effect

Virkus

Thomsen²,

Uggerhøj³

et al. 2008

Phys. Rev. Lett.

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Experimental results for the restricted energy loss of pairs created from 1-178 GeV photons in a thin Au target and subsequently passing a CCD detector are presented. It is shown that pairs-when detected close to the creation vertex-suffer a reduced energy loss due to the internal screening of the charges constituting the pair. Furthermore, the ability to measure directly the energy of the pair by calorimetry enables a comparison with theory as a function of energy. The observed phenomenon is in good qualitative agreement with general expectations from the Chudakov effect but indicates a quantitative disagreement with either of two mutually disagreeing theories. DOI: 10.1103/PhysRevLett.100.164802 PACS numbers: 41.60.ÿm, 07.85.Fv, 29.40.Vj, 95.30.Gv In the preparatory phase of the CERN NA63 experiment, we have investigated the reduced energy deposition from a positron-electron pair in the vicinity of their creation point. This reduction is due to the internal screening of charges, the so-called Chudakov (or King-Perkins-Chudakov) effect [1,2].By taking into account the density effect, a considerable contribution to the ionization energy loss originates from transverse distances b q ' v=! p , where v is the particle speed through the medium with plasma frequency ! p . If a penetrating assembly of separate charges is internally spaced less than this distance, the ionization is influenced by interference terms. This can be the case, e.g., for an energetic hydrogen molecule that is stripped upon entry to the substance, but it can also be an effect present for an electron-positron pair where each participating charge screens the charge of the other as seen from the relevant distance b q in the medium. Because of the Lorentz transformation of angles to the laboratory system, the electron and positron emitted in the pair creation process from a photon of energy @! appear with an approximate angle of 1= mc 2 =E e ' 2mc 2 =@! to the photon momentum @k in the frame of the laboratory. Thus, by defining E e =@! and p @!=mc 2 , we get an opening angle of the pairthe so-called Borsellino angle [3]. The energy loss thus diminishes close to the creation point if the created pair is sufficiently energetic and therefore forward directed. This is the so-called Chudakov effect. In a sense, the Chudakov effect is the pair production analogue of the more familiar density effect in radiation emission.A closely related effect -to both the density effect ([4], Chap. 13.5) and the Chudakov effect-has recently been calculated for Cherenkov radiation emission from e e ÿ pairs in the vicinity of the creation point [5,6]. This internal screening effect may affect decisively the behavior of the Cherenkov emission in neutrino-induced electromagnetic showers. A similar reduction may apply in the case of vacuum-assisted photoionization [7], where the created pair that knocks out the electron may suffer internal screening, leading to a lower photoionization cross section. Finally, the radiation emission from relativistic positronium may be in...

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Cherenkov radiation of e ⁺ e ⁻ pairs and its application for the measurement of gamma-quanta beam polarization

Cited by 6 publications

References 10 publications

Carbon nanotubes and fullerites in high-energy and X-ray physics

Carbon nanotubes and fullerites in high-energy and X-ray physics

Measurements and theories of the King–Perkins–Chudakov effect

Direct Measurement of the Chudakov Effect

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Cherenkov radiation of e + e − pairs and its application for the measurement of gamma-quanta beam polarization

Cited by 6 publications

References 10 publications

Carbon nanotubes and fullerites in high-energy and X-ray physics

Carbon nanotubes and fullerites in high-energy and X-ray physics

Measurements and theories of the King–Perkins–Chudakov effect

Direct Measurement of the Chudakov Effect

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Product

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Cherenkov radiation of e ⁺ e ⁻ pairs and its application for the measurement of gamma-quanta beam polarization