摘要
A non-conventional positron source using the intense y radiation from an axially oriented monocrys- tal which materializes into e^＋e^- pairs in a granular amorphous converter is described. The enhancement of photon radiation by multi-GeV electrons crossing a tungsten crystal along its 〈111〉 axis is reported. The resulting enhancement of pair production in an amorphous converter placed 2 meters downstream, is also re- ported. Sweeping off the charged particles from the crystal by a bending magnet upstream of the converter allows a significant reduction of the deposited energy density. Substituting a granular target made of small spheres for the usual compact one, makes the energy dissipation easier. The deposited energy and correspond- ing heating are analyzed and solutions for cooling are proposed. The configurations studied here for this kind of positron source allow its consideration for unpolarized positrons for the ILC.
A non-conventional positron source using the intense y radiation from an axially oriented monocrys- tal which materializes into e^＋e^- pairs in a granular amorphous converter is described. The enhancement of photon radiation by multi-GeV electrons crossing a tungsten crystal along its 〈111〉 axis is reported. The resulting enhancement of pair production in an amorphous converter placed 2 meters downstream, is also re- ported. Sweeping off the charged particles from the crystal by a bending magnet upstream of the converter allows a significant reduction of the deposited energy density. Substituting a granular target made of small spheres for the usual compact one, makes the energy dissipation easier. The deposited energy and correspond- ing heating are analyzed and solutions for cooling are proposed. The configurations studied here for this kind of positron source allow its consideration for unpolarized positrons for the ILC.
