improving Simulation Geometry section of user manual

Local coordinate systems for the detectors are also right-handed Cartesian systems, with the x- and y-axes defining the

sensor plane. The origin of this coordinate system is the center of the lower left pixel in the grid, i.e. the pixel with

indices (0,0). This simplifies calculations in the local coordinate system as all positions can either be stated in absolute

indices (0,0), whereas the z-axis pointing towards the readout connected to the sensor.

This simplifies calculations in the local coordinate system as all positions can either be stated in absolute

numbers or in fractions of the pixel pitch.

A sketch of the actual coordinate transformations performed, including the order of transformations, is given below. The

global coordinate system used for tracking of particles through detetector setup is shown on the left side, while the local

coordinate system used to describe the individual sensors is located at the right.

global coordinate system used for tracking of particles through detector setup is shown on the left side, while the local

coordinate system used to describe the individual sensors is located at the right. Both local and global coordinate systems are aligned by default.

Therefore, without any rotation, the sensor’s backplane (opposite to the plane where the readout is performed) is turned to the negative side of the z-axis.

![](./transformations.png)\

*Coordinate transformations from global to local and revers. The first row shows the detector positions in the respective

*Coordinate transformations from global to local and reverse. The first row shows the detector positions in the respective

coordinate systems in top view, the second row in side view.*

The global reference for time measurements is the beginning of the event, i.e. the start of the particle tracking through the