Transcript Introduction - PACS at Leuven

PACS IHDR
12/13 Nov 2003
PACS Instrument Overview
A. Poglitsch
MPE
Instrument Design/Development Overview
and
System Performance
PACS Instrument Overview
1
PACS IHDR
12/13 Nov 2003
Instrument Concept
•
Imaging photometry
– two bands simultaneously (60-85 or
85-130 µm and 130-210 µm) with
dichroic beam splitter
Focal Plane Footprint
32 x 16 pixels
6.4” x 6.4”
64 x 32 pixels
3.2” x 3.2”
– two filled bolometer arrays (32x16
and 64x32 pixels, full beam sampling)
– point source detection limit ~3 mJy
(5s, 1h)
•
Integral field line spectroscopy
– range 57 - 210 µm with 5x5 pixels,
image slicer, and long-slit grating
spectrograph (R ~ 1500)
– two 16x25 Ge:Ga photoconductor
arrays (stressed/unstressed)
– point source detection limit
3…10 x10-18 W/m2 (5s, 1h)
PACS Instrument Overview
2
PACS IHDR
12/13 Nov 2003
Observing Modes
• Combinations of instrument modes and satellite
pointing modes
• Instrument modes:
– dual-band photometry
– single-band photometry
– line spectroscopy
• observation of individual lines
– range spectroscopy
• observation of extended wavelength ranges
• Pointing modes:
– stare/raster/line scan
– with/without nodding
PACS Instrument Overview
3
PACS IHDR
12/13 Nov 2003
Instrument Overview and Subsystem Responsibilities
DEC/MEC 1
FPU Cold
FocalPlaneUnit
MEC I/F-Module
BlueGe:GaArray
&CRE
MPE/ASTEQ/IMEC
BOL/COOL
DPU
nominal
SPU
nominal
IAC-Tenerife/TU-Wien
BOL/BAU
DSP Module
BOL 1
Module
BlueBol
BAU
BlueBolArray
&Read-out
CEA
BlueDEC Module
BOL 2
Module
RedBol
BAU
RedBolArray
&Read-out
CEA
Base/PSU
Cooler
Control
CSL-Liege
CEA
RedGe:GaArray
&CRE
MPE/ASTEQ/IMEC
CEA
0.3K Cooler
CEA
DEC/MEC 2
DPU
redundant
IFSI-ROME
Warm Interconnecting
Harness
SPU
redundant
MEC I/F-Module
Redundant
Grating Assy
CSL-Liege
DSP Module
Redundant
Chopper Assy
MPIA
RedDEC Module
2FilterWheels
KT
Base/PSU
Redundant
2CalSources
KT
IAC-Tenerife/TU-Wien
PACS Instrument Overview
CSL-Liege
KT/MPE
4
PACS IHDR
12/13 Nov 2003
FPU/Optics
Photometer
Optics
Blue
Bolometer
FPU Cold
FocalPlaneUnit
Filter Wheel I
Slicer
Optics
0.3 K Cooler
Red
Bolometer
Grating
Grating Drive
Encoder
sGeGaDetector
Red Spectrometer
Spectrometer
Optics
Chopper
Calibrator I and II
Calibrator
Optics
Entrance
Optics
PACS Instrument Overview
BlueGe:GaArray
&CRE
MPE/ASTEQ/IMEC
BlueBolArray
&Read-out
CEA
RedBolArray
&Read-out
CEA
RedGe:GaArray
&CRE
MPE/ASTEQ/IMEC
0.3K Cooler
CEA
Grating Assy
CSL-Liege
Filter Wheel II
Chopper Assy
MPIA
GeGa Detector
Blue Spectrometer
2 FilterWheels
KT
2 Calibrators
KT
KT/MPE
5
PACS IHDR
12/13 Nov 2003
Design/Development Status of Technically
Critical Components
•
•
•
•
•
•
•
Optics
FPU/Structure
Photoconductors, CRE
Bolometers
Chopper
Grating assembly
Warm electronics
PACS Instrument Overview
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PACS IHDR
12/13 Nov 2003
Optics
• Design of FPU optics unchanged, manufacturing of
mirrors complete, filters partly delivered
• Alignment of QM optics in progress, specs fulfilled so
far
• Analyses (geometrical-optical, diffraction) done; to be
complemented by measurements with IL tests/
calibration
• Baffle design and manufacture for QM FPU finished;
optimisation for FM in progress
• Calibration sources manufactured and tested
 Details from N. Geis / D. Kampf
PACS Instrument Overview
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PACS IHDR
12/13 Nov 2003
FPU Status
• Detailed design of FPU structure finished, but thermal
strap interface issues open.
• Manufacture of QM structure complete, manufacture
of FM started
• Cryo-vibration performed on STM
–
–
–
–
–
Photometer STM including cooler and Focal Plane Assembly
Grating STM, including new launch lock (without motor)
One of two filter wheels
Both photoconductor arrays (partly dummies)
Dummy chopper
 Details from J. Schubert and D. Kampf
PACS Instrument Overview
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PACS IHDR
PACS Instrument Overview
12/13 Nov 2003
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PACS IHDR
12/13 Nov 2003
Photoconductor Arrays
• All QM detector “sixpacks” (2 highstress, 2 low-stress) delivered to
MPE / MPIA for testing
• Tests of all low-stress modules
finished at MPIA, all high-stress
modules + a few low-stress
modules tested at MPE after repair
at ASTEQ
• QM schedule tight (critical path) –
see below
– Integration of modules with
housing + filters has to start
• FM schedule driven by
– CREs: FM wafers (CRE v06)
processed, AIT in progress
– New contact (?) problem
PACS Instrument Overview
 Details from H. Richter
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PACS IHDR
12/13 Nov 2003
“Blue” Ge:Ga QM Detector Test Results
A/W
Sixpack2_MPIA
Responsivity of modules in Sixpack1_MPIA
(left: before vibration, right: after vibration)
PACS Instrument Overview
NEP ~ 5x Herschel/PACS BLIP (with QM CRE)
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PACS IHDR
12/13 Nov 2003
“Red” Ge:Ga QM Detector Test Results
600
QM7: responsivity at T=1.9K, C=0.52pF, t=0.25s
P = 4.8e-15 W
detector1
1E-15
QM7: NEP at T=1.9K, C=0.52pF, t=0.25s
P = 4.8e-15 W
detector1
detector 2
detector 2
detector 3
500
detector 3
detector 4
detector 4
detector 5
NEP [W /  Hz]
r [A/W]
detector 5
detector 6
400
300
200
detector 6
detector 7
detector 7
detector 8
detector 8
1E-16
detector 9
detector 9
detector 10
detector 10
detector 11
detector 11
detector 12
detector 12
detector 13
BLIP
detector 15
Herschel/PACS
detector 16
100
detector 13
detector 14
0
20
FM14,0 FM12, FM11
QM12, QM11, QM8
40 QM7, QM9,
60 QM3 80
FM11,
QM12,
QM11,
QM8
bias [mV]
100
detector 14
detector 15
1E-17
0
20
40
bias [mV]
detector 16
60
80
100
• NEP (even with QM CRE) approaching advertised value
• Some “weak” pixels, varying from cooldown to cooldown
• Few “dead” pixels (open channels)
PACS Instrument Overview
 Details from U. Grözinger
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PACS IHDR
12/13 Nov 2003
Cryogenic Read-Out Electronics
• CQM run (v05)
– Integrated in QM modules + test modules
– Tested extensively – current noise too high (at least for
low-stress array – by factor ~5)
– CQM not suitable for FS, but useful for QM ILT
• FM run (v06)
–
–
–
–
Significant design modifications (3 variations implemented)
Wafers processed
First tests very promising in terms of noise performance
Delivery starting Nov/Dec ’03
• FS run my become necessary to reach all specs
– should come in time to allow allow detector swapping
 Details from P. Merken
PACS Instrument Overview
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PACS IHDR
12/13 Nov 2003
QM CRE (v05) Performance
Raw ramp
•
Linearity
: <3%
non-linearity
Blind channel
subtracted
over >2V
•
Cross talk between channels:
<1% full range
• Linearity, cross talk
meet requirements
– with blind channel subtraction
• Noise too high by factor ~5
PACS Instrument Overview
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PACS IHDR
12/13 Nov 2003
Bolometer/Readout Development
Blue Focal Plane
PACS Instrument Overview
• QM blue focal plane array
mounted at LETI
• The working arrays showed a
very large responsivity (good!)
• The working arrays show very
large noise and very slow
response of the clocks, due to
high contact resistance (~MΩ)
at the 2K Buffer Unit level
(known error in QM buffer run
causing poor indium bumps
hybridization)
• A new blue focal plane is being
mounted with FM Buffer Unit
to be used in the CQM
 More from L. Rodriguez et al.
15
PACS IHDR
12/13 Nov 2003
Bolometer/Readout Development
Red Focal Plane
16
Reference
Red array
• A red focal plane with two sub arrays has been assembled
• No tests because of known Buffer Unit problems. Decision to
replace the BU right away
• This detector is now completed and under test
• The measured noise levels are good everywhere except for a few
pixels on each array
Wavelength in microns
• Spectral response measured with FTS; absorption ~80% in band
14
12
10
8
6
4
2
0
50
100
150
200
250
300
350
400
450
500
550
600
500
550
600
1
0.9
0.8
PACS band
Absorption
0.7
0.6
calculated
0.5
0.4
measured
0.3
0.2
0.1
0
50
100
150
200
250
300
350
400
450
Wavelength in microns
PACS Instrument Overview
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PACS IHDR
12/13 Nov 2003
Bolometer Performance Tests
requirement
• Detector bandwidth
measured ~4 - 5 Hz
• “1/f” noise “knee”/
stability measurement:
no significant
increase down
to 0.05 Hz
^ 10-16 W/√Hz (requirement)
=
goal
PACS Instrument Overview
requirement
17
PACS IHDR
12/13 Nov 2003
3He
Sorption Cooler Development
6 10
350
300
Note : HCR#3/upside down
Level 0 at1.66 K
HCR#1 - horizontal
HCR#1 - right side up
HCR#1 - upside down
HCR#2 - horizontal
HCR#2 - right side up
HCR#2 - upside down
HCR#3 - horizontal
HCR#3 - right side up
HCR#3 - upside down
4 10
-5
3 10
-5
2 10
-5
1 10
-5
0
250
0
20
40
60
Cooling power (µW)
First test with 10 µW
applied load:
35 hours @ 291 mK
PACS Instrument Overview
CQM PACS
SPIRE- -Autonomy
Autonomytests
tests
CQM
Nominal
conditions
L0
=
1.7 K
K //L1
L1 ==44 K
K
Nominal conditions - L0 = 1.7
5 10-5
-1
1/time (s )
Temperature (mK)
CQM PACS - Thermal tests June - August 2003
Comparison HCR #1 HCR#2 and HCR#3
Level 1 (titanium frame) : 2 K
Level 0 (cryostat cold plate) : Å 1.6 K
-5
80
100
Theoretical curve
yy==5,3392e-06
+ 0,22163x
R= 0,99898
4,11371e-06
+ 2,09004e-07x
R= 1
0
5 50
10
-5
100
150
0,0001
0,00015
Applied load (µW)
200
0,0002
• extra load of 8-10 µW identified
(potential heat switch problem)
• 10% undercharged
 Details from L. Duband
18
250
0,00025
PACS IHDR
12/13 Nov 2003
Chopper
• QM delivered for integration in
FPU
• Performance demonstrated
• Scratches on mirror
– t.b. avoided with FM
• Tests of chopper control with
DECMEC and LM concluded
• Adjustment of control
parameters for QM only during
IL tests
 Details from R. Hofferbert
PACS Instrument Overview
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PACS IHDR
12/13 Nov 2003
Grating Assembly
• Grating Mechanism/Drive
– STM including new launch-lock (without actuator) passed cryovibration test
• STM mechanism shows better dynamic characteristics than before
vibration. The apparent "friction" torque is roughly reduced by a factor
2 to 3.
• Bearings qualified: no movement noise or hard point over the useful
stroke
– Transformer for Inductosyn position readout shows excellent cold
performance. Dissipation measured  1.5 mW
– CQM delivered to CSL
•
•
•
•
•
Few minor NCRs, one major (connectors swapped)
Functional/performance tests performed
FUB QM transformers integrated in QM ILT
Launch-lock actuator will be integrated
Loose spring washer, shaft-to-bearing coupling part has moved in cryovibration test
PACS Instrument Overview
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PACS IHDR
12/13 Nov 2003
Grating Assembly
• Diffraction grating
– QM grating fully
characterised
– Test of grating
constant
and grating
periodicity: all
parameters in
or near spec
(accepted
by optics SE)
PACS Instrument Overview
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PACS IHDR
12/13 Nov 2003
Warm Electronics: AVM Instrument Level Tests
PACS Instrument Overview
22
PACS IHDR
12/13 Nov 2003
Status of AVM Tests (1)
• CDMS simulator upgrade to V2.4
– Has solved some counter overrun problem and the time bug
(now we have correct TAI)
– Burst mode for PACS implemented
• DPU OBSW: several updates
– Mainly for 1355 link loss investigation
– But solving only the other known problems (EEPROM, jump
to application software)
– Bug found in DPU ISR routine (by comparison with DECMEC)
– New problem with 1553 interface discovered. HW? SW?
DPU problems not solved in >1 year – start of ILT at risk!
• DECMEC OBSW is pretty stable
PACS Instrument Overview
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PACS IHDR
12/13 Nov 2003
Status of AVM Tests (2)
• AVM SPU
– Identified HW problem fixed
– A small problem related to the SPU-DMC 1355 link initial
self-test has been found, but apparently this is inherent to
the SMCS chip. Either the SPU_SUSW and/or the user
manual need to be updated.
• SPU HLSW upgraded to version 6.0
– It contains some performance improvements both with
respect to CPU work load and compression ratio
– Parallel mode will require small update
– Goal for CQM is to develop, in parallel, an improved strategy
(noise estimate from averaged ramp per pixel) and test it
• Down-link of “near-raw” data to allow ramp modeling / glitch
removal on ground
• CPU load down presently still too high, optimisation in progress
PACS Instrument Overview
24
PACS IHDR
12/13 Nov 2003
SPU Ground Simulator
Ground simulation of SPU code useful for several reasons:
• Use PACS “raw data” transmission mode to redo, on
ground, the same operations as performed by the onboard S/W
• Dispose of a test bed to try out new compression
algorithms before they are up-linked and used by onboard S/W
• Subject PACS simulator data to same artifacts, i.e.
compression and reduction, as on-board obtained
data
• New version of on-board SPU has been “grounded” in
less than five minutes work
PACS Instrument Overview
25
PACS IHDR
12/13 Nov 2003
Instrument Performance
• Instrument Requirements
– Photometer
– Spectrometer
• Instrument Model
– Optical performance
– Sensitivity budget
• optical transmission
• background
• detector performance
PACS Instrument Overview
26
PACS IHDR
12/13 Nov 2003
Photometer Performance Requirements
• Image quality
– blur: telescope limited
– distortion: ±1 pixel; alignment: <1/3 pixel
• Sensitivity (point source detection)
– requirement: 5 mJy (5s), 1h of integration
– goal:
3 mJy (5s), 1h of integration
• Dynamic range
– detection from 3 mJy to >1000 Jy (goal: 3000 Jy)
– contrast of up to 1:500 in one field
• Post-detection bandwidth
– requirement: 0.5 - 5 Hz
– goal:
0.05 - 5 Hz
PACS Instrument Overview
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PACS IHDR
12/13 Nov 2003
Spectrometer Performance Requirements
• Image quality
– blur: telescope limited
– distortion: ±1 pixel; alignment: <1/4 pixel
• Sensitivity (point source detection)
– requirement: 3x10-18 W/Hz1/2 (5s), 1h of integration
– goal:
2x10-18 W/Hz1/2 (5s), 1h of integration
• Dynamic range
– detection from ~1x10-18 W to >10-13 W
– contrast of up to 1:100 in one field
• Post-detection bandwidth
– requirement: 5 Hz
– goal:
10 Hz
PACS Instrument Overview
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PACS IHDR
12/13 Nov 2003
Optical Performance
• Optical design / implementation fulfills requirements
regarding
–
–
–
–
–
–
–
–
–
field of view
spatial sampling
distortion
geometrical spot sizes (Strehl ratio)
alignment
internal calibration capability
chopping
spectral coverage and resolution
transmission / diffraction losses
 Details from N. Geis / D. Kampf
PACS Instrument Overview
29
PACS IHDR
12/13 Nov 2003
Parameters of PACS Instrument Model
(Present estimate, partly based on measurements)
optical element
Lyot stop
filters
mirrors
slicer diffraction
level
telescope
baffle
“15 K” optics
“4 K” optics
T
(K)
80
65
15
5.5

0.05
0.01
0.05
0.15
efficiency
photometry
0.9
0.4
0.85
-
effective transmission
photometry spectroscopy
0.31
0.15
0.34
0.16
0.34
0.16
10(b)
4(b)
spectroscopy
0.9
0.4
0.74
0.85
relative bandwidth
photometry
spectroscopy
2.9-1 /2.4-1/2.2-1 (a)
1000-1-4500-1
2.9-1 /2.4-1/2.2-1 (a)
1000-1-4500-1
-1
-1
-1 (a)
2.9 /2.4 /2.2
1000-1-4500-1
1.5-1
1.5-1
(a) Values for the photometry modes from 60-85 or 85-130 µm / 130-210 µm, respectively.
(b) The formal transmission of >1 takes into account the acceptance solid angle of the
photoconductor light cones / bolometer baffles which differs from the beam solid angle.
PACS Instrument Overview
30
Spectrometer Performance
PACS IHDR
eff_g i
0.8
0.8
0.6
0.6
eff_g j
eff_g k
12/13 Nov 2003
eff_ti
0.4
0.4
0.2
0.2
Telescope efficiency
(main beam)
Grating diffraction order efficiency
0
60
80
100
5000
120
6
140
6
 i  10   j  10   k 10
160
180
0
60
80
100
6
120
140
i  10
160
180
6
1
4000
0.8
Ri
3000
Rj
Rk
eff_pi 0.6
2000
0.4
1000
0.2
Main beam / pixel coupling
Resolving power
0
60
80
100
120
6
140
6
 i  10   j  10   k 10
PACS Instrument Overview
160
6
180
0
60
80
100
120
 i  10
140
6
160
180
31
Spectrometer Performance
PACS IHDR
4 10
14
4 10
17
3 10
14
3 10
17
2 10
14
2 10
17
1 10
14
1 10
17
BLIP NEP [W/Hz1/2]
Background power [W]
0
60
80
100
120
140
160
12/13 Nov 2003
0
180
60
80
100
120
140
160
180
17
1 10
8 10
18
6 10
18
4 10
18
2 10
18
Sensitivity [W/m2]
(5s, 1 hour)
0.3
i
j
0.2
k
off-position
chopping
0.1
on-array chopping
Requirement
Detective quantum efficiency
0
60
80
100
120
6
140
6
 i  10   j  10   k 10
PACS Instrument Overview
160
6
180
0
60
80
100
120
140
160
180
32
PACS IHDR
12/13 Nov 2003
Photometer Sensitivity

R
(m)
60 – 85
85 – 130
130 – 210
2.9
2.4
2.2
Telescope
efficiency
0.64
0.73
0.77
Point source detection limit
(5s, 1h) [mJy]
4
goal
3
2
1
0
50
100
150
200
pixel (a)
0.16
0.11
0.18
Background
(W)
4.8  10-12
3.1  10-12
5.1  10-12
BLIP NEP(b)
(W Hz-1/2)
1.8  10-16
1.2  10-16
1.2  10-16
• Assumed detector QE: 80%
(based on FTS
measurements)
• Assumed detector NEP: 10-16
W/Hz1/2 (based on electrical
noise and responsivity
measurements)
• Margin for requirement, goal
likely to be met
Wavelength [µm]
PACS Instrument Overview
33