(ROS2) ray does not work - topic is not published

[PetropoulakisPanagiotis]

here is my .xacro for the ultrasound sensor that is included in the robot.xacro.

I have added the sensor and plugin but I can not see any topic related to the ray sensor. I would appreciate any help. Thank you!

<?xml version="1.0"?>

<robot xmlns:xacro="http://www.ros.org/wiki/xacro">
    <xacro:macro name="ultraSound" params="name *origin">
        <joint name="ultraSound_joint_${name}" type="fixed">
            <xacro:insert_block name="origin"/>
            <parent link="trunk"/>
            <child link="ultraSound_${name}"/>
        </joint>
        <link name="ultraSound_${name}">
            <collision>
            <origin xyz="0 0 0" rpy="0 0 0"/>
            <geometry>
                <box size=".001 .001 .001"/>
            </geometry>
            </collision>

            <visual>
            <origin xyz="0 0 0" rpy="0 0 0"/>
            <geometry>
                <mesh filename="package://go1_description/meshes/ultraSound.dae" scale="1 1 1"/>
            </geometry>
            <material name="black"/>
            </visual>

            <inertial>
            <mass value="1e-5" />
            <origin xyz="0 0 0" rpy="0 0 0"/>
            <inertia ixx="1e-6" ixy="0" ixz="0" iyy="1e-6" iyz="0" izz="1e-6" />
            </inertial>
                        
        <sensor name="ultra_sound_${name}" type="ray">
          <ray>
            <scan>
              <horizontal>
                <samples>300</samples>
                <resolution>1.0</resolution>
                <min_angle>-0.5236</min_angle>
                <max_angle>0.5236</max_angle>
              </horizontal>
              <vertical>
                <samples>100</samples>
                <resolution>1.0</resolution>
                <min_angle>-0.5236</min_angle>
                <max_angle>0.5236</max_angle>
              </vertical>
            </scan>
            <range>
              <min>0.05</min>
              <max>50.0</max>
            </range>s
          </ray>
          <always_on>true</always_on>
          <update_rate>10.0</update_rate>
          <plugin name="ultra_sound_${name}" filename="libgazebo_ros_ray_sensor.so">
            <ros>
              <namespace>/ray</namespace>
              <remapping>~/out:=ultra_sound_${name}</remapping>
            </ros>
            <output_type>sensor_msgs/PointCloud2</output_type>
          </plugin>
	  </sensor> 
	  
	  
        </link>
        
    </xacro:macro>
</robot>