Method for detecting pressure, and pressure sensor

A vacuum pressure sensor (10), comprising:

• a sample chamber (20) in which a plasma can be generated, wherein the sample chamber has electrical contact with a first electrode (1) and with a second electrode (2),
• a current measuring device (42) electrically connected to the first and to the second electrodes and connected in series with the sample chamber,
• a wavelength-selective element (51, 54),
• a first (31) and a second detector element (32) for measuring a radiation intensity of an electromagnetic radiation,
• wherein the wavelength-selective element, the first detector element and the second detector element are arranged such that in the first detector element only electromagnetic radiation of a first wavelength range emanating from the sample chamber can arrive, and that in the second detector element only electromagnetic radiation of a second wavelength range emanating from the sample chamber can arrive, and
• wherein at least a first emission line of a first plasma species of a first chemical element lies in the first wavelength range, wherein a second emission line of the first plasma species of the first chemical element or of a second plasma species of the first chemical element lies in the second wavelength range, and wherein the second emission line lies outside the first wavelength range, and
• a measurement chamber (3) surrounding the sample chamber, having a window (5) in a wall or as a wall of the measurement chamber,
• wherein the window is transparent in an optical wavelength range and wherein a continuous first radiation path is defined which, starting from the sample chamber, traverses the window and ends in the first detector element, and
• wherein a continuous second radiation path is defined which, starting from the sample chamber, traverses the window and ends in the second detector element.