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.
@article{arxiv.1705.03912,
title = {A short-orbit spectrometer for low-energy pion detection in electroproduction experiments at MAMI},
author = {D. Baumann and M. Ding and I. Friščić and R. Böhm and D. Bosnar and M. O. Distler and H. Merkel and U. Müller and Th. Walcher and M. Wendel},
journal= {arXiv preprint arXiv:1705.03912},
year = {2017}
}