Big Boss CCD Camera Aka: BBcam

1. Big Boss CCD Camera Aka: BBcam

2. CEA-Saclay/Irfu: Experience in CCD cameras • Eros-II (1996) • 2 CCD cameras • 8 CCDs 2048x2048 • Cryocooler with cold head interface • Eros (1990) • 16 CCDs 580x400 • Simple liquid nitrogen cryostat • MegaCam (2002) • 40 CCDs 2048x4612 • Cryocooler with pulsed tube 2

3. Megacam CCD test bench Before the camera integration the CCDs have to be characterized.

4. Megacam CCD test bench

5. Megacam CCD population

6. Megacam CCD « saturnin » Dynamic > 16 bits ! Signal linear resolution! No dead colons! Sevral hour pose! More than 9/10 photons detected !

7. Megacam CCD QE Rendement Quantique

8. Megacam CCD testing

9. Megacam elements 40 CCDs focal plane Measure and regulation of thetemperature Fixation of focal plane to hot cryostat Bring the cold power from cryogenerator to focal plane Connect CCD to electronics

10. Focal plane • Nb de pixel: 360 millions • Mosaïque: • 2 rangées de 11 + 2 rangées de 9 CCDs (E2V CCD42-90 2K x 4.5K pixels) • Aboutement: 4 côtés • Assemblage: • Support CCD directement vissé sur la plaque froide • Planéité: ± 16 µm • Usinage des bandes supports de la plaque froide • Connexion: • Connecteur « ZIF » sur la face arrière du support CCD • Plaque froide: • Aluminium avec revêtement en Nickel • Température PF: 140K • Température CCD: 150K

11. Megacam cryo-cooling • Cooling by cryogenerator in closed cycle • Tube pulsé 90W @140K develop by DRFMC/SBT • Regulation on 2 level: • By adaptation of the thermal Resistance (Cu braids) • By resistance glued on the cold plate

12. CCD electronic Lecture time: 30s; 166Kpixel/s Mean noise on 80 outputs: 4,5 e- Mean conversion factor: 1,65 e-/ADU Mean non-linearity : 0,5% Total dissipation : 300W PCB plug on the vacuum connector Home-made vacuum connector 2000 contacts Elec. Boxes on the cryostat

13. Expertise in CCD cameras Know-how from EROS I et II, Megacam, and now-day Euclid • Cryostat conception • vacuum, cryogenics closed cycle system • Cryogenics regulation • CCD Integration & metrology • CCD Characterization • Electronics et DAQ • CCD camera Maintenance (Megacam)

14. Existing equipments at Saclay Equipment since Megacam • Clean room class 10.000 et 100 • Adjacent test rooms • Optical metrology machine • CCD characterization test bench • Used by Euclid • Cold room(-5 to 20°c)

15. Big Boss Camera 30 cameras with a single CCD each • Aka: Megacam divided in 20 small cameras BB-Cam •  Simple objet •  Serial integration (spare: i.e. 11 cameras) •  Easy environment (room) •  Cooling dispatching •  Higher cost (mechanics, vacuum,…)

16. BBCam concept « Underground » cameras distribute in space • Individual or dispatched cooling ? • Studies for cold dispatching for lower cost • Studies: • Cooling with cryogenerator and cryo-connexion • Cooling with liquid N2 External cryostat tip-tilt and focus alignment External electronic for easy access ( and CCD safety !) and low cameras power dissipation

17. R&D cryo-connection (2010) Design and test a cryo-connection on 20 to 50 cm • Copper braid inserted in a flexible tombac (vacuum tube) cold through a cryo-bus • Separated vacuum for cameras, cryo connection and cryo-bus • Cold connection uncoupling while cold • 2 FTE and ~150 k$ in 2010 Study on cluster size (4 to 10 cameras)

18. Cluster cooling solution Control-command connexion Cold bar Cryo bus Vacuum port Gate valve CCD 4kx 4K SiC cold plate Window: Last lenses Cryo cooler Elec. Cold braid

19. Cluster cooling solution 180 K on CCD 160 K on cold connexion 110 K on cold connexion 100 K on cold head Elec. Elec. Elec. Elec. Elec. 80 W @ 100 K

20. Megacam first light!!!