1. iALMA WP4 – ALMA band 2 passive components
Science and Technology in Italy for the upgraded ALMA Observatory
WP4 – ALMA band 2 passive components
Renzo Nesti

2. Outline WP4: Summary WP4: Development WP4: Risks WP4: Devices
WP4: Done some preliminary work
WP4: Band 2 or Band 2+3 ?

3. WP4 Summary Development of new technology and instrumentation for ALMA
Aimed to develop a prototype band 2 cartridge for ALMA
Design prototyping and test of band 2 passive front-end: Refocusing Mirror System (MIRRORS) Corrugated feed horn (Feed) Orthomode transducer (OMT)
Band 2 Vs Band 2/3 from the passive front-end point of view

4. WP4 Summary External Links Management Science Receiver Laboratory
Green E
Outreach
WP4
Passive Components
WP5
Cartridge Prototyping
WP9
Cartridge Electronics/SW

5. WP4 Development
First year activity

6. Activity in subsequent years
WP4 Development
1st year activity enhancement due to the work done in the recent meanwhile with respect to the original proposal Engineering of FEED, OMT and possibly MIRRORS Fabrication of FEED, OMT and possibly MIRRORS
Activity in subsequent years
2nd year activity Set up facilities and environments for measurements Software development for data acquisition and processing Electromagnetic test on FEED, OMT and MIRRORS
3rd , 4th year activity Test analysis and critical design review Test report and WP4 documentation production Support to WP5 activity (cartridge system)

7. WP4 Risks
Hardware: Prototyping of Feed, OMT and mirrors (1st year), mainly with band 2/3 specs
Testing (2nd year): Procurement of (1st year, call for tender)

8. WP4 Devices Mirrors or lens ?
J. W. Lamb et al. ‘ALMA Receiver Optics Design’ ALMA Memo 362, Apr 2001

9. WP4 Devices
Mirrors
Cold or Warm Optics ?
GBA + PO

10. WP4 Devices
Feed

11. WP4 Devices Feed Array of 7 elements at Q band High reproducibility
High software accuracy
About 20 micron tolerances

12. WP4 Devices
CW_y
OMT
CW_y
CW_x
CW_x X Y

13. WP4 Devices OMT CNC machining prototype at Q-Band High reproducibility
High software accuracy
About 20 micron tolerances

14. WP4 Devices
OMT
Measurements

15. WP4 Band 2 or band 2+3 ? Band 2 to Band 2+3 extension:
Passive front-end design more difficult. One reason…..

16. WP4 Done some preliminary work
ALMA Band 2+3: Electroformation hypothesis
Copper elettroformation hypothesis
About π x 20 x 20 x 40 mm3 volume
About 30 g weight

17. WP4 Done some preliminary work
ALMA Band 2+3: Lathe hypothesis
44 aluminum lathe machined plates
About π x 36 x 36 x 60 mm3 volume
About 90 g weight

18. WP4 Done some preliminary work
ALMA Band 2: CNC milling hypothesis
8 aluminum equal-thick layers sandwiched by two plates
About 43 x 43 x 30 mm3 volume
About 100 g weight

19. WP4 Done some preliminary work
ALMA Band 2/3: CNC milling hypothesis
11 aluminum not equal-thick layers sandwiched by two plates (8 AND equal-thick)
Minimum milling tool diameter of 0.5 mm (1 mm)
About 46 x 46 x 38 mm3 volume (43 x 43 x 30)
About 150 g weight (100 g)
(vs Band 2 OMT features)