Pan-STARRS Preliminary Requirements Review 04 Aug 03 Pan-STARRS Preliminary Requirements Review 04 Aug 03 PanSTARRS Gigapixel Camera PanSTARRS Gigapixel Camera System System Scope of Gigapixel Camera effort. WIYN telescope collaboration. OTA development status OTA test plan OTA package, focal plane and cryostat design. OTA controller electronics design and development. Outline John Tonry (IFA), Gerard Luppino (IFA), Peter Onaka (IFA), Barry Burke (MITLL)
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Pan-STARRS Preliminary Requirements Review 04 Aug 03 PanSTARRS Gigapixel Camera System Scope of Gigapixel Camera effort. WIYN telescope collaboration.
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Pan-STARRS Preliminary Requirements Review 04 Aug 03Pan-STARRS Preliminary Requirements Review 04 Aug 03
PanSTARRS Gigapixel Camera PanSTARRS Gigapixel Camera SystemSystem
Scope of Gigapixel Camera effort. WIYN telescope collaboration. OTA development status OTA test plan OTA package, focal plane and cryostat
design. OTA controller electronics design and
development.
OutlineJohn Tonry (IFA), Gerard Luppino (IFA), Peter Onaka (IFA), Barry Burke (MITLL)
Pan-STARRS Preliminary Requirements Review 04 Aug 03Pan-STARRS Preliminary Requirements Review 04 Aug 03
Scope of Gigapixel Camera EffortScope of Gigapixel Camera Effort
YES Maybe? NO
OTA Detectors• OTA Packages• OTA Focalplane• Camera Cryostat• OTA Controller Electronics• Camera Diagnostics• Host Image Acquisition Computers • Software for OTA operation• Software for Guiding.• Detector Calibration Info. (e.g. flats, biases, darks, linearity, etc.)
Host Computer Network Shutter Detectors for Telescope collimation and focus. Instrumental Signature Info. (fringing, scattered light, etc.) Cryostat Window
Filter Server Instrument Rotator (if Alt/Az) Telescope Control Telescope optical alignment Sky probe hardware and software Flatfield Illumination Scheduler Software Pipeline Software
Part of Detector/Camera System Scope?
Pan-STARRS Preliminary Requirements Review 04 Aug 03Pan-STARRS Preliminary Requirements Review 04 Aug 03
Non Binding Collaboration WIYN Developing One-Degree Imager (ODI)
• Camera System Nearly Identical to one of the PanSTARRS Gigapixel Cameras.
WIYN Contribution PanSTARRS Contribution
Develop 2nd source for OTAs• STA (Bredthauer)
WIYN Telescope time for OTA testing. Procurement of large filters. Detector testing and characterization. MONSOON controller
Lend four OTAs for WIYN/QUOTA camera Design for QUOTA camera (copy of PanSTARRS test camera). OTA package design. OTA operating software OTA controller design.
Pan-STARRS Preliminary Requirements Review 04 Aug 03Pan-STARRS Preliminary Requirements Review 04 Aug 03
OutlineOutline
Overview of OTA Principal design and process
challenges• Pixel layout• Logic design, fabrication, and recent
results• Metallization and interconnects
Other OTA design issues and options• Die size and pads• Enhanced substrate E fields• Compatibility of design with CMOS option• Mini-OTA (MOTA) options
Process options and lot-1 splits Design status and summary
Pan-STARRS Preliminary Requirements Review 04 Aug 03Pan-STARRS Preliminary Requirements Review 04 Aug 03
Orthogonal Transfer Array Orthogonal Transfer Array (OTA)(OTA)
88 array of small OTCCDs , each ~500 500 pixels*
OTCCD cells independently clocked via on-chip control logic
Cells read out one row at a time at 1-MHz read rate; readout time ~ 2 s
Subset of cells (typically five) selectable for tracking guidestars at ~30-Hz rates
*(12 um: 480 x 496; gaps 9 x 28, 10 um: 574 x 594; gaps 11 x
35)
OTCCD cells
Pan-STARRS Preliminary Requirements Review 04 Aug 03Pan-STARRS Preliminary Requirements Review 04 Aug 03
Pan-STARRS Preliminary Requirements Review 04 Aug 03Pan-STARRS Preliminary Requirements Review 04 Aug 03
OTA/CMOS Hybrid SensorOTA/CMOS Hybrid Sensor
After bonding After CCD thinning, pad-via etch,back-surface treatment
Pan-STARRS Preliminary Requirements Review 04 Aug 03Pan-STARRS Preliminary Requirements Review 04 Aug 03
Mini OTAsMini OTAs
MOTA is 22-cell version of OTA
Opportunity to try advanced features
• Two-phase serial register• Dual output gates• Higher performance logic
designs Useful as monitor devices
(QE, PSF, etc.) ~12 die possible Fits in conventional PGA
Tentative wafer layout
Pan-STARRS Preliminary Requirements Review 04 Aug 03Pan-STARRS Preliminary Requirements Review 04 Aug 03
Process Splits for Lot 1Process Splits for Lot 1
10m
Type 1
Type 1 Type 2
Type 2
12m 12m
10m
Wafers Split Options
1-4 Baseline process
5-8 CMOS
9-10 CMOS + deeper depletion
11-13 Metal over gates
14-16Metal over gates + deeper depletion
17-19Deeper depletion + higher resistivity
20-22 Deeper depletion
23-24 Look ahead
Pan-STARRS Preliminary Requirements Review 04 Aug 03Pan-STARRS Preliminary Requirements Review 04 Aug 03
Test Plan for OTAsTest Plan for OTAs
Device selection phase (Mar –Jun 2004)• Approximately 16 different devices
– Pixel size, CMOS logic, deeper depletion, shutter, etc.• MOTAs with more exotic choices• Serious, thorough testing necessary during a short time
which will lead to final, production OTA design choices.
Production testing (Oct 2004 – Oct 2006)• Wafer probe frontside for S/O (powered up?); excise cells?• Wafer probe backside, cold (packages are valuable)• OTA test, tune, and select• 300 OTAs need testing (20,000 CCDs!), so we need well
designed, stable test setups, software, and analysis tools.
Pan-STARRS Preliminary Requirements Review 04 Aug 03Pan-STARRS Preliminary Requirements Review 04 Aug 03
Design Selection PhaseDesign Selection Phase
Clocking / pixel performance• CTI• Pocket density• Cosmetics• Dark current• Image persistence• QE non-uniformity, fringing• QE• Full well• Clocking time constants• Charge diffusion• Goodies
– Electronic shutter– 2-phase serial
Pan-STARRS Preliminary Requirements Review 04 Aug 03Pan-STARRS Preliminary Requirements Review 04 Aug 03
Slop2• Determine and subtract bias level• Generate and subtract “local sky”• Reconstruct split pixels (if requested)• Identify K-alpha pixel values as a function of (x,y)• Fit a plane
Gain derived from plane intercept at (0,0) Noise derived from overclocks CTE parallel from y slope, CTE serial from x slope Other features sometimes visible in pixel value
plots
Pan-STARRS Preliminary Requirements Review 04 Aug 03Pan-STARRS Preliminary Requirements Review 04 Aug 03
This chip has a number of bright defects that I tried to minimize by cooling to –130
The chip loses 3.6% across 2048 serial pixels, hence CTI_serial = 4.77
It loses 1.5% across 4096 parallel pixels, hence CTI_parallel = 5.44
This poor behavior is because it’s at –130C, and would not be detectable optically – the trap time is so long that any edge pattern would look very sharp.
Pan-STARRS Preliminary Requirements Review 04 Aug 03Pan-STARRS Preliminary Requirements Review 04 Aug 03
• Charge diffusion will be more important in the future– Better red response
requires thicker devices– CCD cost is proportional to
area, so smaller pixels are desirable
– Diffusion is proportional to CCD thickness
• The distribution of split pixel values is sensitive to the charge diffusion, and Fe55 x-rays can provide a sensitive measure of diffusion length – 0.33 pixel = 5m in this case.
Pan-STARRS Preliminary Requirements Review 04 Aug 03Pan-STARRS Preliminary Requirements Review 04 Aug 03
Optical Testing - QEOptical Testing - QE
Measure about 20 points, especially where QE is changing rapidly.
Similar devices are probably very similar – don’t bother QE testing all of them.
Good opportunity to characterize fringing and other non-flatness (e.g. brick wall pattern in the blue)
Pan-STARRS Preliminary Requirements Review 04 Aug 03Pan-STARRS Preliminary Requirements Review 04 Aug 03
Test Data and DatabaseTest Data and Database
Typical test data• Dark images (3 temps, 3 exposure times: 0, 100, 1000 sec)• X-ray images (4 VDD, 4 clock volts, 3 clock speeds)• Monochromator images (20 wavelength, 8 exposure time x 4
VDD)• Focussed images (8 exposure time x 4 VDD)
– Test pattern (look at resolution)– Image with structure (look for linearity)– Point sources (look for cross-talk, image persistence)– Low level uniform and pocket pumping
Detector database• 300 OTA x 100 images x 32 Mb = 1 Tb• 20,000 CCD x (Noise, gain, QE, CTI, dark, full well, linearity,
cosmetics, pocket density, diffusion, preferred biases and clock volts and timings, comments, etc, etc…)
This requires a high degree of organization and uniformity!
Pan-STARRS Preliminary Requirements Review 04 Aug 03Pan-STARRS Preliminary Requirements Review 04 Aug 03
Controller software• Gbit ethernet tested Aug• Compact PCI throughput Aug• Centroid & shift Aug/Sep• Pixel server software Nov• OTA control development Oct-Dec
Test suite• Define tests Sep 1• Design test bench Oct 1• Define software Oct 15• Acq/fab test bench Nov 15• Test software complete Jan 1, 2004
Pan-STARRS Preliminary Requirements Review 04 Aug 03Pan-STARRS Preliminary Requirements Review 04 Aug 03
ScheduleSchedule
Cryostat• Package design Oct 1• Dewar and focal plane Nov 1• Hermetic cabling Dec 1• Packages complete Jan 1, 2004
Detectors• Layout finished Aug 15• Layout checked Sep 2• Masks ordered Sep 4• Start lot Sep 8• Frontside chips available Mar 1, 2004• CMOS addressing chips avail Mar 15, 2004• Thinned OTAs available May 15, 2004• Decision on Lot 2 design Jun 30, 2004
Pan-STARRS Preliminary Requirements Review 04 Aug 03Pan-STARRS Preliminary Requirements Review 04 Aug 03
PSF ShapingPSF Shaping
Planet occultations• Jupiter at 10-2, Earth at 10-4
S/N of 104 per readout by psf shaping• Jupiter easy, Earth possible…