Simplify reflection code slightly

                position = Eigen::Vector3d(intercept.x(), intercept.y(), intercept.z());

            } else {

                // geom. reflection on x-y plane at upper sensor boundary (we have an implant on the lower edge)

                ROOT::Math::XYZPoint reflected_position(position.x(), position.y(), 2. * intercept.z() - position.z());

                position = Eigen::Vector3d(reflected_position.x(), reflected_position.y(), reflected_position.z());

                LOG(TRACE) << "Carrier was reflected on the top boundary of the sensor to: "

                           << Units::display(static_cast<ROOT::Math::XYZPoint>(position), {"nm"});

                position = Eigen::Vector3d(position.x(), position.y(), 2. * intercept.z() - position.z());

                LOG(TRACE) << "Carrier was reflected on the sensor surface to "

                           << Units::display(static_cast<ROOT::Math::XYZPoint>(position), {"um", "nm"});

            }

            LOG(TRACE) << "Moved carrier to: " << Units::display(static_cast<ROOT::Math::XYZPoint>(position), {"nm"});

        }

        // update position according to reflection etc.

        // Update final position after applying corrections from surface intercepts

        runge_kutta.setValue(position);

        // Update step length histogram