Title: A short-orbit spectrometer for low-energy pion detection in electroproduction experiments at MAMI,
Abstract: A new Short-Orbit Spectrometer (SOS) has been constructed and installed
within the experimental facility of the A1 collaboration at Mainz Microtron
(MAMI), with the goal to detect low-energy pions. It is equipped with a
Browne-Buechner magnet and a detector system consisting of two helium-ethane
based drift chambers and a scintillator telescope made of five layers. The
detector system allows detection of pions in the momentum range of 50 - 147
MeV/c, which corresponds to 8.7 - 63 MeV kinetic energy. The spectrometer can
be placed at a distance range of 54 - 66 cm from the target center. Two
collimators are available for the measurements, one having 1.8 msr aperture and
the other having 7 msr aperture. The Short-Orbit Spectrometer has been
successfully calibrated and used in coincidence measurements together with the
standard magnetic spectrometers of the A1 collaboration.