The PowerMonitor (PM) uses the same calorimetric principle as the CompactPowerMonitor. In contrast to the flat absorber in the CPM, the laser beam in the PowerMonitor is directed via a focusable mirror into a cylindrical absorber. A highly absorbent coating has been applied to the inside of the water-cooled absorber. The cylindrical absorber allows very high degrees of absorption with minimal back-reflection.
This method is suited to very high powers. All parts that come into contact with the cooling water are manufactured from copper or brass. In this way stress corrosion is effectively prevented in the cooling cycle. A pneumatic closing device protects the PowerMonitor against dirt contamination.
In developing the PowerMonitor, the focus was on the following requirements:
- absorption of high-intensity beams
- high degree of absorption
- long-term stability
- short acquisition time
- reliable operation in tough operating environment