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Future Developments ofInfrared Controllers at ESO
Gert Finger
Next Generation IR Detectors
Detector Format Outputs Pixel Time Frame Time Baud Rate[µs] [ms] Gbaud
Hawaii-2RG MBE HgCdTe 2Kx2K 32 0.2 26 2.6Si:As BIB 640x480 32 0.3 2.8 1.7ORION 2Kx2K InSb 2Kx2K 64 1.5 100 0.7Adaptive optics sensors 256x256 32 0.2 0.41 2.6
l need 5 MHz 16 bit ADC’sl need 3 Gbaud fiber link
Future Requirements forIRACE
l Large format mosaics of 4x4x2Kx2K IR arrayseach having >= 32 parallel video outputs (VISTA)
l Subpixel sampling by digital filter in EPLDl Reference unit cells for true differential signal chainl Interpolated digital clamp of reference unit celll Embedded real time pre-processing in high level
programming language such as IDL ( cosmic ray rejection)l Guiding on science framel diagnostics , self test of acquisition system, on line helpl Audio DAC’s to control clock slopes ?l Put detector front end in ASIC close to focal plane
Large Format : VISTA
IR imager
1.2°
1.67°
l 4 meter telescope, field 1.67 degl mosaics of 4x4x2Kx2K IR arrays
bench
Slide provided byMark Casali / UKATC
l eight filter units, eachcontaining sixteen filters,each 54mm square
l with HAWAII2 mux usefour quadrants fortracking,guiding andwave-front sensing
l with HAWAII2-RG useguiding feature built intodetector
Large Format: VISTA
Slide provided byMark Casali / UKATC
IR imagerfocal plane module
16 detectors
2 boards and 2 external connectorsper detector
thermal bus bars [4]
base plate
housing
Integrate cryo-opamps and filters in flex board
VISTA focal plane
l 16 2Kx2K arrayseach having 32parallel outputs
l 512 channelIRACE system
l readout time 1.3 s
Slide provided byMark Casali / UKATC
Digital filter in EPLD of AQ1616-Bit
16-Bit
ADC withoutput register 16-Bit
ADC withoutput register 16-Bit
ADC withoutput register 16-Bit
ADC withoutput register 16-Bit
ADC withoutput register 16-Bit
ADC withoutput register 16-Bit
ADC withoutput register 16-Bit
ADC withoutput register 16-Bit
16-Bit
16-Bit
16-Bit
16-Bit
16-Bit
16-Bit
16-Bit
16-Bit
Ana
log
inpu
t sig
nal
Ana
log
inpu
t sig
nal
Ana
log
inpu
t sig
nal
Ana
log
inpu
t sig
nal
Ana
log
inpu
t sig
nal
Ana
log
inpu
t sig
nal
Ana
log
inpu
t sig
nal
Ana
log
inpu
t sig
nal
ADC withoutput register 16-Bit
ADC withoutput register 16-Bit
ADC withoutput register 16-Bit
ADC withoutput register 16-Bit
ADC withoutput register 16-Bit
ADC withoutput register 16-Bit
16-Bit
16-Bit
16-Bit
16-Bit
16-Bit
16-Bit
16-Bit
16-Bit
Ana
log
inpu
t sig
nal
Ana
log
inpu
t sig
nal
Ana
log
inpu
t sig
nal
Ana
log
inpu
t sig
nal
Ana
log
inpu
t sig
nal
Ana
log
inpu
t sig
nal
Ana
log
inpu
t sig
nal
Ana
log
inpu
t sig
nal
16
-B
it b
us
(lo
w w
or
d o
f 3
2-
Bi
t b
us
)
16
-B
it b
us
(h
igh
wo
rd
of
32
-B
it b
us
)
Output register 16-Bit
Dsu
b 37
-pin
s co
nnec
tor
only
ana
log
sign
als
Mon
itorin
g of
ana
log
inpu
t sig
nals
Amplifier & analog multiplexer
EPLDcontrol unit
ADC withoutput register 16-Bit
ADC withoutput register 16-Bit
Off
set e
limin
atio
ns
of a
nalo
g in
put s
igna
l
P2 b
ackp
lane
con
nect
orD
ata
I/O b
us (G
iga
bus)
Output register 16-Bit
VMEInterface
P1 b
ackp
lane
con
nect
orV
ME
inte
rfac
e
l process subpixel samplesin EPLD
l parallel processing1 processor /AQ board
l digital filter of video signal
Conversionstrobes
Video signal
AQ 16 board
Reference unit cell (Hawaii2)l 8 video outputs / quadrantl 128 pixels in fast directionl reference pixel for thermal
drift is 129 th pixel on 9 th outputl 36 channels / detector required
Video and Reference Signal of Hawaii 2 at end of Row
0.00
1.00
2.00
3.00
4.00
5.00
1.48E-03 1.50E-03 1.52E-03 1.54E-03 1.56E-03 1.58E-03 1.60E-03
Time [s]
Sig
nal
[V] Video
Reference
CLK1
External reference with Hawaii1l No reference output
provided on chipl external reference has to
be used
Gain=1+2RF/RG
On chip reference cell of Hawaii2l reference pixel for
thermal drift compensationand suppression of pickupis 129 th pixel on 9 th output
l reference pixel notavailable while readingpixels
l clock first to referencepixel
l clamp reference pixel withcryogenic sample and hold
l read pixels of row withclamped voltage atreference input of cryo-opamp
Gain=1+2RF/RG
On chip reference cell of Hawaii2-RGl reference pixel for
thermal drift compensationand suppression of pickupon 9 th output, but
l reference pixel availablewhile reading pixels
l read pixels of row withvoltage of reference cell atreference input ofcryo-opamp
l best suppression of noisepickup
Gain=1+2RF/RG
50 Hz pickup of Hawaii2without clamp of reference
l multiple sampling reduces readout noise andrequires lower pickup noise
l Clock each row once and read oncel reference output ( 129 th pixel on 9 th output ) is
not usedl 32 channels / detector required
Video and Reference Signal of Hawaii 2 at end of Row
0.00
1.00
2.00
3.00
4.00
5.00
1.48E-03 1.50E-03 1.52E-03 1.54E-03 1.56E-03 1.58E-03 1.60E-03
Time [s]
Sig
nal
[V] Video
Reference
CLK1
Video and Reference Signal of Hawaii 2 at end of Row
0.00
1.00
2.00
3.00
4.00
5.00
1.48E-03 1.50E-03 1.52E-03 1.54E-03 1.56E-03 1.58E-03 1.60E-03
Time [s]
Sig
nal
[V] Video
Reference
CLK1
Row n-1 Row n
ref n a ref n a
50 Hz pickup of Hawaii2 with digital clamp
l Clock each row once and read oncel read reference after reading row and and
subtract reference signal for each pixelsig nk =pix nk - refna
l 36 channels / detector required
Video and Reference Signal of Hawaii 2 at end of Row
0.00
1.00
2.00
3.00
4.00
5.00
1.48E-03 1.50E-03 1.52E-03 1.54E-03 1.56E-03 1.58E-03 1.60E-03
Time [s]
Sig
nal
[V] Video
Reference
CLK1
Video and Reference Signal of Hawaii 2 at end of Row
0.00
1.00
2.00
3.00
4.00
5.00
1.48E-03 1.50E-03 1.52E-03 1.54E-03 1.56E-03 1.58E-03 1.60E-03
Time [s]
Sig
nal
[V] Video
Reference
CLK1
Row n-1 Row n
ref n-1 a ref n a
50 Hz pickup of Hawaii2with interpolated digital clamp
l Clock each row twice and read oncel read reference before and after reading row and
interpolate reference signal for each pixelsig nk =pix nk - (ref nb - (ref nb -ref na)*(k-1)/127)
l 36 channels / detector requiredl reference allows rejection of low frequency
pickup and compensation of thermal drifts
Video and Reference Signal of Hawaii 2 at end of Row
0.00
1.00
2.00
3.00
4.00
5.00
1.48E-03 1.50E-03 1.52E-03 1.54E-03 1.56E-03 1.58E-03 1.60E-03
Time [s]
Sig
nal
[V] Video
Reference
CLK1
Video and Reference Signal of Hawaii 2 at end of Row
0.00
1.00
2.00
3.00
4.00
5.00
1.48E-03 1.50E-03 1.52E-03 1.54E-03 1.56E-03 1.58E-03 1.60E-03
Time [s]
Sig
nal
[V] Video
Reference
CLK1
Row n Row n
ref n b ref n a
Aladdin #3 & #4#4: QE H = 0.86 darkcurrent = 0.004 e/s
#5: QE H = 0.82 (ISAAC) darkcurrent = 0.017 e/s
Monitor temperature driftusing dead pixels
l Triangles:measuredintegration ramp
l Diamonds:dead pixels
l Open In bump bondsare used to monitordrifts
l Squares:drift correctedintegration ramp
l darkcurrentat 28.5 K:0.017 e/s/pixel
Temperature drift of deadpixels in Aladdin array
l Temperature drift:1700 electrons / K
l required temperaturestability of array:6 mK
l temperature drift willbe monitored withreference unit cell ofHawaii-2RG
Elimination of cosmic rays bymultiple sampling
Warm pixels continuous integration ramp
Cosmic rays create charge burstand step in integration ramp
Cosmic Ray Correction
l At Paranal (altitude 2600 m) 2038 pixels / hour are hit
l maximum charge injected by comic ray ~ 2E4 electrons < full well (1E5 electrons)
l correction by multiple nondestructivesampling and real time processing in IRACEnumber cruncher using idl routines
l at present more warm pixels than cosmics,but arrays may improve (MBE)
Parallel Processing of DetectorData in IRACE
l mark digitized videosignal with differentheaders
l process video signalin IRACE numbercruncher (ULTRA-SPARC) for scienceframe
l process subwindowin PowerPC on VMEbus for real timeapplications
Conclusion
l Mosaics of 2Kx2K arrays are comingl need 5 MHz 16 bit ADC’s and 3 Gbaud fiber linkl use of unit cell reference for true differential signal
chainl more real time image processing with faster
processorsl General purpose ASIC needed for ground based
applications