1. WVR workshop, Wettzell, 2006 10 10Miroslav Pantaleev Development of the Dicke-switched WVR prototype for ALMA Magne Hagström, Lars Pettersson and Leif Helldner Collaboration with

2. WVR workshop, Wettzell, 2006 10 10Miroslav Pantaleev

3. WVR workshop, Wettzell, 2006 10 10Miroslav Pantaleev Development of the Dicke-switched prototype for the ALMA WVR  Radiometer design - Double Dicke  Critical components  Lab tests  SMA - tests  Single Dicke prototype

4. WVR workshop, Wettzell, 2006 10 10Miroslav Pantaleev Optics layout - Double Dicke M5 C2 M4 C1 M3  Chopper wheel to select between sky - calibration  Measure all the time  Cryo cooler as cold load  Warm mixers and LNA

5. WVR workshop, Wettzell, 2006 10 10Miroslav Pantaleev Calibration Hot and Cold Solenoid Vane Hot load

6. WVR workshop, Wettzell, 2006 10 10Miroslav Pantaleev Chopper wheel function and design goals  Reliable > 10 years of continuous running  Small blade diameter – cut a small beam waist  Phase locked to external square wave

7. WVR workshop, Wettzell, 2006 10 10Miroslav Pantaleev Chopper blade  Dynamically balanced chopper wheel  No holes to avoid turbulences

8. WVR workshop, Wettzell, 2006 10 10Miroslav Pantaleev Chopper support  Bearings – SKF  Lifetime – more than 25 years (depending on the operational rpm)  Flexible coupling to dump vibrations

9. WVR workshop, Wettzell, 2006 10 10Miroslav Pantaleev Chopper protective cover

10. WVR workshop, Wettzell, 2006 10 10Miroslav Pantaleev Chopper blade positioning

11. WVR workshop, Wettzell, 2006 10 10Miroslav Pantaleev Chopper timing

12. WVR workshop, Wettzell, 2006 10 10Miroslav Pantaleev Measured chopper data Chopper blade jitter

13. WVR workshop, Wettzell, 2006 10 10Miroslav Pantaleev Block diagram Double Dicke

14. WVR workshop, Wettzell, 2006 10 10Miroslav Pantaleev Mixer

15. WVR workshop, Wettzell, 2006 10 10Miroslav Pantaleev 3 dB, 91.6 GHz power divider  Waveguide branch type couplers – many section required to cover wide bandwidth  Double probe structure is coupled to the E-field in a waveguide By courtesy of V.Vassilev

16. WVR workshop, Wettzell, 2006 10 10Miroslav Pantaleev DSB - Noise temperature Double Dicke

17. WVR workshop, Wettzell, 2006 10 10Miroslav Pantaleev Sensitivity

18. WVR workshop, Wettzell, 2006 10 10Miroslav Pantaleev Filter bands  The LO frequency is kept very close to line frequency.  Mixers are double sideband.  Four IF channels with larger bandwidth away from the centre of the line.

19. WVR workshop, Wettzell, 2006 10 10Miroslav Pantaleev Filter and video assembly

20. WVR workshop, Wettzell, 2006 10 10Miroslav Pantaleev Custom designed filters  Bandpass filter B (1.565GHz – 2.315GHz)  Ring resonators bandpass filter  Compact, low insertion-loss, sharp- rejection, and wide-band application

21. WVR workshop, Wettzell, 2006 10 10Miroslav Pantaleev Calibration reference loads Two reference temperatures with a  T  150 K, one of them close to sky the temperature  Peltier element - not possible to get below – 50 ºC  Noise diode - only  4 dB ENR Sterling cooler  Cool a microwave absorber to below 150 K.  Stabilize the temperature of the absorber to < 0.05 K  Absorber reflectivity > 30 dB at 183 GHz.  Maintenance free time  10 years.

22. WVR workshop, Wettzell, 2006 10 10Miroslav Pantaleev Cooling power

23. WVR workshop, Wettzell, 2006 10 10Miroslav Pantaleev Cooled load mount

24. WVR workshop, Wettzell, 2006 10 10Miroslav Pantaleev Thermal stabilization Insulation Frame with Peltier cooler IF temperature regulation

25. WVR workshop, Wettzell, 2006 10 10Miroslav Pantaleev Single Dicke

26. WVR workshop, Wettzell, 2006 10 10Miroslav Pantaleev Block diagram Single Dicke

27. WVR workshop, Wettzell, 2006 10 10Miroslav Pantaleev Optics layout - Comparison

28. WVR workshop, Wettzell, 2006 10 10Miroslav Pantaleev Physical size comparison: Double -Single Dicke Cost saving pre-production design work  Single Dicke Receiver  Replacement of the Hymatic Sterling cooler with a Peltier cooler  Replacement of the cold load with a cool/hot load combination

29. WVR workshop, Wettzell, 2006 10 10Miroslav Pantaleev Cold load  Single Dicke Receiver  Replacement of the Hymatic Sterling cooler with a Peltier cooler  Replacement of the cold load with a cool/hot load combination

30. WVR workshop, Wettzell, 2006 10 10Miroslav Pantaleev Current status

31. WVR workshop, Wettzell, 2006 10 10Miroslav Pantaleev IF linearity