Advantages of axially aligned crystals used in positron production at future linear colliders

CAS, ThéorieThe characteristics of the electron-photon showers initiated by 2 to 10 GeV electrons aligned along the ⟨111⟩ axis of tungsten crystals are compared with those for the amorphous tungsten. In this energy range, as known, the positron yield at the optimal target thicknesses is larger in a crystal case only by several percent. However, the amount of the energy deposition in a crystal turns out to be considerably (by 20%–50%) lower than in an amorphous target providing the same positron yield, while the peak energy-deposition density is approximately of the same magnitude in both cases