<p>The sensor (12) has a reinforcement tube (5) made of a material whose thermal expansion coefficient is higher than that of a material of a protective tube (9). The reinforcement tube is firmly connected with the protective tube in a region (10) of the protective tube. A stop element (6) is firmly connected with the protective tube in another region (11) of the tube. The reinforcement tube comes in mechanical contact with the stop element due to its higher thermal expansion at a given temperature, so that the sensor is mechanically stabilized at the temperature.</p>
