# A short-orbit spectrometer for low-energy pion detection in electroproduction experiments at MAMI

## TL;DR

The paper introduces a newly developed Short-Orbit Spectrometer at MAMI designed for detecting low-energy pions in electroproduction experiments, with detailed description of its construction, calibration, and successful application.

## Contribution

It presents the design, construction, and calibration of a novel spectrometer specifically for low-energy pion detection in electroproduction experiments.

## Key findings

- Successfully calibrated and operated the spectrometer.
- Detected pions with momenta of 50-147 MeV/c.
- Enabled coincidence measurements with existing spectrometers.

## 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.