Steering of sub-GeV positrons by ultrathin bent silicon crystal for ultraslow extraction applications

For the first time at the Beam Test Facility (BTF) of the <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mi>DA</a:mi><a:mi mathvariant="normal">Φ</a:mi><a:mi>NE</a:mi></a:mrow></a:math> accelerator complex at the Laboratori Nazionali di Frascati of INFN, 450 MeV positrons have been deflected with high efficiency, using the planar channeling process in a bent silicon crystal. The deflection angle obtained is beyond 1 mrad. This interesting result finds several applications for manipulation of this kind of beams, in particular for ultraslow extraction from lepton circular accelerators like <d:math xmlns:d="http://www.w3.org/1998/Math/MathML" display="inline"><d:mrow><d:mi>DA</d:mi><d:mi mathvariant="normal">Φ</d:mi><d:mi>NE</d:mi></d:mrow></d:math>. In this work, the experimental apparatus, the measurement procedure, and the experimental results are reported.