Transcript
A Gigapixel commercially-manufactured cryogenic camera for the J-PAS 2.5m survey telescope Paul R Jorden 2 July 2012
P R Jorden1, M Bastable1, M Clapp2, S Darby1, M Dryer1, T Eaton1, G Fenemore-Jones1, P Jerram1, A Marin-Franch3, I Palmer1, R Pittock1, P Pool1, R Renshaw1, K Taylor4, N Waltham2, P Wheeler1 1
e2v
2
RAL
SPIE AS12
3
CEFCA
4
IAG/USP
Conference 8453
Contents J-PAS 2.5m camera
• • • • • • • • • •
Introduction Summary of requirements CCDs Focal Plane Assembly CCD electronics Cryostat and cooling Camera System Challenges Summary Acknowledgements
Main purpose is Dark Energy survey through BAO measurements
Slide 2
Introduction
Cryogenic camera system for J-PAS 2.5 m telescope Javalambre Physics-of-the-Accelerating-Universe Astrophysical Survey Concept design of the camera is described•
Science, Autoguide, & WFS CCDs integrated into precision focal plane
•
Integrated pumping, LN2 cooling, vacuum cryostat, and control system
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Custom local electronics designed for 4 e- read-noise from 224 science channels
•
Digital signal sampling [DCDS] and 1.2 G-pix science data frames
Shutter, filters, camera mounting to telescope not included Slide 3
Summary of Requirements
Primary Requirements •14 Science CCDs; 3o FOV; 476 mm Φ • 9216 X 9216 10 um pixel science CCDs • Low read-noise and < 10 s readout time • 12 aux. CCDs for guiding & image quality • Control electronics & multiple modes • Volume & mass limits for camera specified • Design for reliability & 10 year (min.) use • Precision focal plane location & flatness
e2v provides “Camera Subsystem”
• Cryogenics, vacuum and thermal control
Camera has interfaces to Cryostat Support Structure, filter/shutter unit, telescope Slide 4
CCDs -1 CCD290-99 Fourteen Science CCDs
• • • • •
12.0 NES electrons (rms)
•
Estimated Read Noise (BI)
9216 X 9216 10 um pixels 92 X 92 mm size 16 outputs 10 second readout at 500 kHz Backthinned; deep depletion; multi-4 AR coating 2 e- read noise floor [single output; 50 kHz] Precision flatness, SiC buttable package
10.0 8.0 6.0 4.0 2.0 0.0 1.0E+04
1.0E+05
1.0E+06
1.0E+07
Frequency (Hz)
Predicted QE at -100°C DD Si Astro multi-4 AR 100% 90% 80% 70% 60% QE
•
50% 40% 30% 20% 10% 0% 300
350
400
450
500
550
600
650
700
750
800
850
900
950 1000 1050 1100
Wavelength (nm)
Slide 5
CCDs -2 CCD44-82 (image quality) and CCD47-20 (guiders)
Both types• Custom packages • Flex cable connectors • Low noise [5 e- goal] • Differential outputs used
Wavefront sensors- CCD44-82
Guiders- CCD47-20
• 4 pairs of sensors in focal plane
• Four sensors in focal plane
• 2048 X 2048 Frame-transfer
• 1024 X 1024 Frame-transfer
• 500 X 500 window at 4 sec read time
• 50 X 50 window at 5 fps
• +/- 1 mm intra/extra focal planes
• Co-planar with science CCDs Slide 6
Focal Plane Assembly- 1
14 science CCDs (9k9k) 4 guide CCDs (1k1k FT) 8 WFS CCDs (2k2k FT)
40 um p-v flatness overall 173K nominal operation Height/tilt adjusted in cryostat 500 mm Φ assembled cold plate with CCDs
Slide 7
Focal Plane Assembly- 2
Thermal/structural FEA modelling ÅÆ detailed design ÅÆ customer agreement
• Concept design • Modelling • Detailed design • Manufacture • Assemble • Test, including Metrology • Iterate (we hope not!)
Slide 8
CCD electronics- 1
SCIENCE CCD 1 of 14
WFS CCD 1 of 8
GUIDE CCD 1 of 4
LC DUPLEX FIBRE OPTIC CABLES
WITH CAMERALINK RECEIVER CARDS
SCIENCE ARRAY DATA (x2) WFS DATA GUIDE DATA
FPGA COMMAND HANDLER CAMERALINK TO FIBRE OPTIC TRANSLATOR
SCIENCE DATA TRANSFER WFS AND GUIDE DATA STREAMED
BIAS DAC
OVERSAMPLING ADC
DATA
FPGA
POWER
POWER
FPGA
INTERFACE MODULE
REMOTE PC(s)
OVERSAMPLING ADC
DATA
FPGA DSP DATA FILTERING CCD TIMING OUTPUT DATA SERIALISER LOCAL FRAMESTORE
BIAS DAC
CLOCK DRIVERS
DRIVER MODULE (1 of 4)
OVERSAMPLING ADC
POWER
BIAS DAC
CLOCK DRIVERS
DATA
CLOCK DRIVERS
DRIVER MODULE (1 of 4)
CCD FLEXIS
DRIVER MODULE (1 of 14)
CCD CONTROLLER ENVELOPE
VACUUM FEEDTHROUGH CONNECTORS
• • • •
CRYOSTAT ENVELOPE
The CCD system- controller architecture
POWER CONVERSION FILTERING AND DISTRIBUTION DC-DC CONVERSION DRIVER MODULE POWER MONITORING AND SWITCHING
48V DC POWER SUPPLY
Slide 9
CCD electronics- 2 Drive module CCD DRIVE MODULE COMPONENTS (1 of 22)
CCD DRIVE MODULE LAYOUT (1 of 22)
CCD290
Drive Module •
One for each science CCD; one will drive two WFS CCDS
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Drives and processes the analogue video from one CCD290-99
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Power dissipation 35W; water cooled
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8-channel digitiser card- designed by RAL
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Bridge board designed by e2v (timing, clock driving, framestore)
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Includes data and power connections to the Interface Module
8 channel digitiser
8 channel digitiser
CCD290-99
FPGA
FPGA
DCDS
DCDS
VAC FEEDTHROUGH
TO INTERFACE MODULE
FPGA Driver/Comms
3 Gb/s
100MHz ref. clock
Power
See RAL reference later for DCDS system
Slide 10
CCD electronics- 3 Interface module
Interface Module •
Hub for CCD data & transfer to control PCs
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Generates multiple voltage rails from incoming 48V
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System monitoring
INTERFACE MODULE
DATA & COMMAND HANDLING
IMAGE DATA
POWER CONDITIONING TO DRIVE MODULE
POWER CONVERSION
48V DC
Slide 11
CCD electronics- 3 Mechanical layout
Main features • Short flex cables in vacuumFrom CCD to vac. conn. • One vac. connector per CCDAll mounted to sealing plate • Multiple drive modules with one interface moduleAt ambient & water cooled • Simple connections externallyPower and fibres only
Slide 12
Cryostat and Cooling
Liquid nitrogen cooling • Liquid/gas piped from remote LN2 Dewar • Two rotary couplings for cryogen • Cryogen passes through sorption pump into chamber • Cryogen cools copper ring which attaches to focal-plane plate VacuumTurbo pump & gate valves for sorb isolation during regeneration Slide 13
The camera system-1 System components
MAINS SUPPLY
CRYOSTAT
UPS Vacuum & Temperature Control (PLC)
EXTERNAL LN2 TANK (mounted on fork) LN2 Sensors & Controls
COLDPLATE SENSORS, HEATERS VALVES, PUMPS
comms EtherCAT Network Cables
Control Room PC(s)
CCD Controller
Custom LN2 cooling system
Thermal control of focal plane
Vacuum control 4 x LC duplex fibre optic connections
48V DC PSU
CCD electronics
MAINS SUPPLY
Designed for telescope operation
Slide 14
The camera system- 2 Mechanical layout
Non-e2v items (transparent)Shutter/filter unit
Vac pump
Adjustable cryostat mount Focal plane chamber
Cryogen feed
CCD electronics
System control electronics Slide 15
Challenges
Challenges • Set of wafer-size CCDs; high performance and guaranteed specifications • Design and make precision FPA; assemble very carefully! • Design and make a 224-channel low-noise electronics system • Lots of data handling, throughput, and storage • Design & make a novel large cryogenic camera- with high stability in use • Handling a large heavy structure in clean room conditions Lots of customer interfaces • AMOS \ telescope mounting, cabling, services, access • CEFCA \ Observatory coordination & telescope specifications • Other J-PAS members or sub-contractors (design & manufacture) \ Shutter & Filter unit, Cryostat support unit, etc
Slide 16
Summary
J-PCAM on 2.5 m telescope LN2 tank
1.2 GPix camera summary Complete astronomical camera • Science, Guide, & WFS CCDs • Precision Focal Plane Assembly • Cryogenic FPA cooling included • Integrated CCD electronics • State-of-the-art performance • Vacuum system included • Approx 600 kg weight • 24 month programme •
LN2 Rotary couplings Camera
Slide 17
Acknowledgements
J-PAS collaboration• Centro de Estudios de Física del Cosmos de Aragón (CEFCA), IAA-CSIC, IFCA • Universidade de São Paulo (USP), Observatorio Nacional de Río de Janeiro (ON) With funding agencies in Brazil and Spain. Others organisations involved• AMOS, CEFCA, RAL Thanks to• Numerous e2v colleagues associated with J-PAS project • Numerous members of J-PAS & associated organisations (as above) • Jean-Louis Lizon (ESO) for advice Other references• M Clapp, RAL, “Development of DCDS readout system..”, 8453-49, this conference • Taylor et al, “JPCAM…”, 8446-36 this meeting, 2012. Other AS12 J-PAS papers also • www.e2v.com • http://j-pas.org/ • See also Atwood et al, 8446-246, KMTNet large format CCD camera
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