1. Effects of spatially inhomogeneous photomultiplier sensitivity….. http://www.freudenthaler.de/ILRC22 Effects of spatially inhomogeneous photomultiplier sensitivity on lidar signals and remedies Volker Freudenthaler Meteorologisches Institut der Universität München, Munich, Germany R5600 V. Simeonov et al., Influence of the Photomultiplier Tube Spatial Uniformity on Lidar Signals, Appl. Opt. 38, 5186-5190 August 1999.

2. Effects of spatially inhomogeneous photomultiplier sensitivity….. http://www.freudenthaler.de/ILRC22 Hamamatsu PMT R5600 / R7400 included in modules: H57xx H67xx H7468 H7155 H7825 H7829 R7400 R5600 old new

3. Effects of spatially inhomogeneous photomultiplier sensitivity….. http://www.freudenthaler.de/ILRC22 MULIS - Multi Purpose Lidar System from telescope 500 mm Optical design for 3 backscatter + 2 extinction + 1 depolarisation channel

4. Effects of spatially inhomogeneous photomultiplier sensitivity….. http://www.freudenthaler.de/ILRC22 POLIS - Portable Lidar System

5. Effects of spatially inhomogeneous photomultiplier sensitivity….. http://www.freudenthaler.de/ILRC22 Biaxial lidar model for ray tracing Considered parameters axial distance of laser and telescope laser axis tilt laser divergence discrete ray source cross sections Software: ZEMAX-EE

6. Effects of spatially inhomogeneous photomultiplier sensitivity….. http://www.freudenthaler.de/ILRC22 Biaxial lidar model for ray tracing Considered parameters axial distance of laser and telescope laser axis tilt laser divergence discrete ray source cross sections Software: ZEMAX-EE

7. Effects of spatially inhomogeneous photomultiplier sensitivity….. http://www.freudenthaler.de/ILRC22 Focal spot positions Range  angle of incidence  radial position of focal spots 5 km 150 m

8. Effects of spatially inhomogeneous photomultiplier sensitivity….. http://www.freudenthaler.de/ILRC22 Focal spot positions  PMT Range  angle of incidence  radial position of focal spots 5 km 150 m

9. Effects of spatially inhomogeneous photomultiplier sensitivity….. http://www.freudenthaler.de/ILRC22 Image of tele-focus on PMT

10. Effects of spatially inhomogeneous photomultiplier sensitivity….. http://www.freudenthaler.de/ILRC22 Image of tele-focus on PMT

11. Effects of spatially inhomogeneous photomultiplier sensitivity….. http://www.freudenthaler.de/ILRC22 Spot positions on PMT over range Ratio to real signal

12. Effects of spatially inhomogeneous photomultiplier sensitivity….. http://www.freudenthaler.de/ILRC22 Radial shift of axis position on PMT vertical and horizontal shift ±1 mm Ratio to real signal

13. Effects of spatially inhomogeneous photomultiplier sensitivity….. http://www.freudenthaler.de/ILRC22 Horizontal and vertical orientation of PMT horizontal vertical vertical horizontal Ratio to real signal

14. Effects of spatially inhomogeneous photomultiplier sensitivity….. http://www.freudenthaler.de/ILRC22 Diffusor Diffusor doesn't help if not very far from PMT  high loss of signal intensity  bad especially for Raman channels Spot PMT ratio to real signal

15. Effects of spatially inhomogeneous photomultiplier sensitivity….. http://www.freudenthaler.de/ILRC22 How to find the best PMT position large image of primary mirror (PM)  large PMT necessary

16. Effects of spatially inhomogeneous photomultiplier sensitivity….. http://www.freudenthaler.de/ILRC22 How to find the best PMT position

17. Effects of spatially inhomogeneous photomultiplier sensitivity….. http://www.freudenthaler.de/ILRC22 How to find the best PMT position

18. Effects of spatially inhomogeneous photomultiplier sensitivity….. http://www.freudenthaler.de/ILRC22 Spot on PMT with eyepiece 150 m PMT -1 0 +1 mm

19. Effects of spatially inhomogeneous photomultiplier sensitivity….. http://www.freudenthaler.de/ILRC22 Spot on PMT with eyepiece over range 150 m PMT -1 0 +1 mm

20. Effects of spatially inhomogeneous photomultiplier sensitivity….. http://www.freudenthaler.de/ILRC22 Biaxial spots on PMT over range – Spot does move axial position 0 mm Ratio to real signal

21. Effects of spatially inhomogeneous photomultiplier sensitivity….. http://www.freudenthaler.de/ILRC22 Biaxial spots on PMT with eyepiece + Spot does not move – change of intensity distribution axial position 0 mm Ratio to real signal

22. Effects of spatially inhomogeneous photomultiplier sensitivity….. http://www.freudenthaler.de/ILRC22 Biaxial spots on PMT with eyepiece + Spot does not move – change of intensity distribution axial position +1mm Ratio to real signal

23. Effects of spatially inhomogeneous photomultiplier sensitivity….. http://www.freudenthaler.de/ILRC22 Biaxial spots on PMT with eyepiece + Spot does not move – change of intensity distribution axial position -1 mm Ratio to real signal

24. Effects of spatially inhomogeneous photomultiplier sensitivity….. http://www.freudenthaler.de/ILRC22 Eyepiece + diffusor

25. Effects of spatially inhomogeneous photomultiplier sensitivity….. http://www.freudenthaler.de/ILRC22 Eyepiece + diffusor + mirror tube "Smart diffusor"

26. Effects of spatially inhomogeneous photomultiplier sensitivity….. http://www.freudenthaler.de/ILRC22 Biaxial spots on PMT with smart diffusor + Spot does not move + no change of intensity distribution axial position noncritical Ratio to real signal

27. Effects of spatially inhomogeneous photomultiplier sensitivity….. http://www.freudenthaler.de/ILRC22 Monoaxial spots on PMT + Spot does not move – change of intensity distribution axial position 0 mm Ratio to real signal

28. Effects of spatially inhomogeneous photomultiplier sensitivity….. http://www.freudenthaler.de/ILRC22 Monoaxial spots on PMT + Spot does not move – change of intensity distribution axial position -1 mm Ratio to real signal

29. Effects of spatially inhomogeneous photomultiplier sensitivity….. http://www.freudenthaler.de/ILRC22 Monoaxial spots on PMT + Spot does not move – change of intensity distribution axial position +1 mm Ratio to real signal

30. Effects of spatially inhomogeneous photomultiplier sensitivity….. http://www.freudenthaler.de/ILRC22 Monoaxial spots on PMT with eyepiece axial position 0 mm Ratio to real signal + Spot does not move + little change of intensity distribution

31. Effects of spatially inhomogeneous photomultiplier sensitivity….. http://www.freudenthaler.de/ILRC22 Solutions DiffusorEyepieceSmart Diffusor signal loss:highnolow design:simpleray tracing accuracy needs:lowhighlow effort:lowhigh

32. Effects of spatially inhomogeneous photomultiplier sensitivity….. http://www.freudenthaler.de/ILRC22 Solutions DiffusorEyepieceSmart Diffusor signal loss:highnolow design:simpleray tracing accuracy needs:lowhighlow effort:lowhigh mechanical accuracy:better than ± 1 mm lens focal lengths: better than ± 1% (± 2% usual)  optical control of result necessary

33. Effects of spatially inhomogeneous photomultiplier sensitivity….. http://www.freudenthaler.de/ILRC22 End Thank you for your attention!