The CosMO mill (Cosmic Muon Observer) is permanently installed at DESY Zeuthen. It consists of a rotating frame on which two CosMO detectors are mounted at a fixed distance of 97 cm.

Driven by a stepper motor, the position of the mill arm is changed every hour by 15 degrees within an interval of -90 to 90 degrees. This hourly rotation allows us to study the dependence of the rate of cosmic particles on the zenith angle.

To filter false signals, the two detectors are switched in coincidence. This means that only those signals are evaluated which were measured by both detectors. This coincidence circuit at a detector distance of almost one meter also reduces the aperture angle of the experiment and thus enables a more precise determination of the direction of the particles.



Data Structure

Possible Student Exercises

Example Diagrams