Method for monitoring radiation
A method for monitoring radiation by an optical sensor which generates a signal, such as a shut-off signal, which influences the radiation when subjected to radiation. A sensor with dark current pulses is used, which are assessed as a functional capability signal of the sensor.
1. A method for monitoring a radiation, in particular a laser radiation, the method comprising:
evaluating a dark current pulse rate of an optical sensor;
subjecting the optical sensor to said radiation;
monitoring the dark current pulse rate of the optical sensor; and
if the dark current pulse rate of the optical sensor drops below a minimum pulse rate, generating a shut-off signal of said radiation.
2. The method according to claim 1 , wherein the optical sensor is constructed as an active optical sensor a passive optical sensor.
3. The method according to claim 1 , wherein the optical sensor comprises one of a Single Photon Avalanche Diode (SPAD) and an Avalanche Photo Diode (APD).
4. The method according to claim 1 , comprising generating said shut-off signal of said radiation also if said dark current pulse rate of the optical sensor exceeds a maximum pulse rate.
5. The method according to claim 1 , comprising evaluating said dark current pulse rate twice along different evaluation paths.
6. The method according to claim 1 , comprising enclosing said optical sensor by one of a protective enclosure and a beam protection wall.
7. The method of claim 6 , wherein said beam protection wall is a passive beam protection wall.
8. The method according to claim 1 , comprising providing a closable opening in said one of the protective enclosure and the beam protection wall.
9. An apparatus for monitoring a radiation, in particular a laser radiation, the apparatus comprising:
an optical sensor arranged to receive said radiation;
said optical sensor being arranged to monitor a dark current pulse rate of said optical sensor;
said optical sensor being arranged for generating a shut-off signal of said radiation if the dark current pulse rate of the sensor drops below a minimum pulse rate.
10. The apparatus according to claim 9 , wherein said optical sensor is constructed as an active optical sensor, or a passive optical sensor.
11. The apparatus according to claim 9 , wherein said sensor comprises one of a Single Photon Avalanche Diode (SPAD) and an Avalanche Photo Diode (APD).
12. The apparatus according to claim 9 , comprising generating said shut-off signal of said radiation also if said dark current pulse rate of the optical sensor exceeds a maximum pulse rate.
13. The apparatus according to claim 9 , comprising two different evaluation paths to evaluate said dark current pulse rate.
14. The apparatus according to claim 9 , wherein said optical sensor is enclosed by one of a protective enclosure and a beam protection wall.
15. The apparatus according to claim 14 , wherein said one of a protective enclosure and a beam protection wall comprises a closable opening.
16. The apparatus of claim 14 , wherein said beam protection wall is a passive beam protection wall.