Future aspects of X-ray emission from crystalline undulators at positron channeling

In connection with ideas to produce undulator-like radiation in the hundreds of keV up to the MeV region by means of positron and electron channeling, there is renewed interest to study various channeling phenomena also experimentally. With electrons experiments have been performed at the Mainz Microtron MAMI to explore channeling-radiation emission by a 4-period epitaxially grown strained layer SiGe undulator. Unfortunately, high quality positron beams of sufficient intensity are not easily accessible. The only serious candidate in Europe seems to be the Beam Test Facility at INFN LNF Frascati, Italy. Some requirements to extend BTF in a facility which is also well suited for positron channeling-radiation experiments will be outlined.