相关论文: Advantages of axially aligned crystals used in pos…
Various positron distributions are obtained using an approach developed earlier for the description of electron-photon showers in axially aligned single crystals. Based on these distributions, characteristics of the positron yield measured…
Numerical simulations and `proof of principle' experiments showed clearly the interest of using crystals as photon generators dedicated to intense positron sources for linear colliders. An experimental investigation, using a 10 GeV…
New kind of positron sources for future linear colliders, where the converter is a tungsten crystal oriented on the <111> axis, has been studied at CERN in the WA103 experiment. In such sources the photons which create the $e^+ e^-$ pairs…
We have observed a significant enhancement in the energy deposition by $25$--$100~\mathrm{GeV}$ photons in a $1~\mathrm{cm}$ thick tungsten crystal oriented along its $\langle 111 \rangle$ lattice axes. At $100~\mathrm{GeV}$, this…
The electron induced production of positrons is a multi-parameter problem which combines elementary physics processes with complex collection systems. The optimization of this technique for 120~MeV and 1000~MeV electron beam kinetic…
An intense positron sources is a demanding element in the design of future lepton colliders. A crystal-based hybrid positron source could be an alternative to a more conventional scheme based on the electron conversion into positron in a…
In a conventional positron source driven by a few GeV electron beam, a high amount of heat is loaded into a positron converter target to generate intense positrons required by linear colliders, and which would eventually damage the…
It is known that the alignment of an high-energy e- beam with specific crystal directions leads to a significant increase of the coherent radiation emission. This enhancement can be exploited to create an intense photon source. An elective…
Radiation emitted by unpolarized high-energy electrons penetrating crystals may be linearly polarized. This occurs when the particle velocity makes an angle, with respect to some major crystal axis, being sufficiently larger than the…
The low-energy effective theories for gapped insulators are classified by three parameters: permittivity $\epsilon$, permeability $\mu$, and theta angle $\theta$. Crystals with periodic $\epsilon$ are known as photonic crystals. We here…
We report new experimental results obtained on three different laser facilities that show directed laser-driven relativistic electron-positron jets with up to 30 times larger yields than previously obtained and a quadratic (~ E^2)…
Under quite generic assumptions the general expression is derived for the probability of circularly polarized photon emission from the longitudinally polarized electron and for the probability of pair creation of longitudinally polarized…
We discuss the features of a crystalline undulator of the novel type based on the effect of a planar channeling of ultra-relativistic electrons in a periodically bent crystals. It is demonstrated that an electron-based undulator is feasible…
Dense positrons are shown to be effectively generated from laser-solid interactions in the strong-field quantum electrodynamics (QED) regime. Whether these positrons are polarized has not yet been reported, limiting their potential…
The spectral distribution of electron-positron pair created by photon and the spectral distribution of photons radiated from high-energy electron in an oriented single crystal is calculated using the method which permits inseparable…
Pair creation by a photon in an oriented crystal is considered in a frame of the quasiclassical operator method, which includes processes with polarized particles. Under some quite generic assumptions the general expression is derived for…
The possibilities of the extraction and collimation of a circulating beam by a new method due to the reflection of particles in crystals with axial orientation were experimentally investigated in the Fall-2010 run at the U_70 synchrotron.…
We present new results regarding the features of high energy photon emission by an electron beam of 178 GeV penetrating a 1.5 cm thick single Si crystal aligned at the Strings-Of-Strings (SOS) orientation. This concerns a special case of…
We have recorded channeling patterns produced by 1 to 2 MeV protons aligned with <111> axes in 55 nm thick silicon crystals which exhibit characteristic angular structure for deflection angles up to and beyond the axial critical angle,…
We report the results of theoretical and numerical analysis of the crystalline undulators planned to be used in the experiments which are the part of the ongoing PECU project [1]. The goal of such an analysis was to define the parameters…