PACS IBDR 27/28 Feb 2002 PACS Instrument Overview1 Instrument Design/Development Status and System...
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Transcript of PACS IBDR 27/28 Feb 2002 PACS Instrument Overview1 Instrument Design/Development Status and System...
PACS Instrument Overview 1
PACS IBDR 27/28 Feb 2002
Instrument Design/Development Status and
System Performance
PACS Instrument Overview
A. Poglitsch
MPE
PACS Instrument Overview 2
PACS IBDR 27/28 Feb 2002
Instrument Concept• Imaging photometry
– two bands simultaneously (60-85 or 85-130 µm and 130-210 µm) with dichroic beam splitter
– two filled bolometer arrays (32x16 and 64x32 pixels, full beam sampling)
– point source detection limit ~3 mJy (5, 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 2…8 x10-18 W/m2 (5, 1h)
Focal Plane Footprint
32 x 16 pixels6.4” x 6.4”
64 x 32 pixels3.2” x 3.2”
PACS Instrument Overview 3
PACS IBDR 27/28 Feb 2002
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 4
PACS IBDR 27/28 Feb 2002
CEA
BOL/BAU
BlueBol BAU
RedBol BAU
Warm Interconnecting Harness
Instrument Overview and Subsystem Responsibilities
DPU nominal
DPU redundant
IFSI-ROME
DEC/MEC 2
MEC I/F-Module Redundant
DSP Module Redundant
RedDEC Module
Base/PSU Redundant
CSL-Liege
BOL/COOL
BOL 1 Module
BOL 2 Module
Cooler Control
CEA
FPU Cold FocalPlaneUnit
KT/MPE
BlueGe:GaArray &CRE
MPE/ANTEC/IMEC
BlueBolArray &Read-out
CEA
RedBolArray &Read-out
CEA
RedGe:GaArray &CRE
MPE/ANTEC/IMEC
0.3K Cooler CEA
Grating Assy CSL-Liege
Chopper Assy MPIA
2FilterWheels KT
2BlackBodies KT
SPU nominal
SPU redundant
IAC-Tenerife/TU-Wien
IAC-Tenerife/TU-Wien
CSL-Liege
DEC/MEC 1
MEC I/F-Module
DSP Module
BlueDEC Module
Base/PSU
PACS Instrument Overview 5
PACS IBDR 27/28 Feb 2002
DPU
• Single point of communication with satellite
• TC/TM– reception and
execution or distribution of commands
– transfer of science and HK data
– autonomy functions
PACS Instrument Overview 6
PACS IBDR 27/28 Feb 2002
DPU
(NOM)
(RED)
SPU 1(NOM)
SPU 2(RED)
DEC/MEC 1
DEC/MEC 2
1355 SWL-SPU1/2SWL DETECTORDATA & STATUS
1355 LWL-SPU1/2LWL DETECTORDATA & STATUS
SPU1 ANALOG HK DATA
SPU2 ANALOG HK DATA
S/C CMD
S/C CMD
28V+SYNC
28V+SYNC
1355 SWL-SPU1TC/TM
1355 LWL-SPU1TC/TM
1355 SWL-SPU2TC/TM
1355 LWL-SPU2TC/TM
SWL-SPU
LWL-SPU
PSU
DAU
SPU
• Data compression– lossy part
(average / fit)– lossless part
(redundancy removal)
• Must reduceraw data rate from up to3.6 Mbit/s to ~120 kbit/s
PACS Instrument Overview 7
PACS IBDR 27/28 Feb 2002
DECMEC
• Photoconductor operation and readout– CRE supply and timing/control– detector bias– signal acquisition
• FPU mechanisms control/ synchronization– chopper– filter wheels– grating
• BOLC data acquisition and control• Communication with SPU and
DPU
PACS Instrument Overview 8
PACS IBDR 27/28 Feb 2002
BOLA / BOLC
BOLA• 160-channel JFET
buffer at ~100 KBOLC• Acquisition of signals
from 160 multiplexers in bolometer arrays
• Sequencer for bolometer operation / readout
• Control of 300 mK cooler
• Transfer of digitized data to DECMEC
PACS Instrument Overview 9
PACS IBDR 27/28 Feb 2002
FPU/Optics
FPU Cold FocalPlaneUnit
KT/MPE
BlueGe:GaArray &CRE
MPE/ANTEC/IMEC
BlueBolArray &Read-out
CEA
RedBolArray &Read-out
CEA
RedGe:GaArray &CRE
MPE/ANTEC/IMEC
0.3K Cooler CEA
Grating Assy CSL-Liege
Chopper Assy MPIA
2 FilterWheels KT
2 Calibrators KT
Chopper
sGeGaDetectorRed Spectrometer
Blue Bolometer
Red Bolometer
Calibrator I and II
0.3 K Cooler
Filter Wheel I
Filter Wheel II
Grating
GeGa DetectorBlue Spectrometer
Encoder
Grating Drive
Entrance Optics
PhotometerOptics
Calibrator Optics
SlicerOptics
SpectrometerOptics
PACS Instrument Overview 10
PACS IBDR 27/28 Feb 2002
Design/Development Status of Technically Critical Components
• Optics• FPU/Structure• Photoconductors, CRE• Bolometers• Chopper• Grating assembly• Warm electronics
PACS Instrument Overview 11
PACS IBDR 27/28 Feb 2002
Optics
• Design of FPU optics complete, manufacturing of mirror blanks started
• Alignment plan exists; tolerancing partly done• Analyses (geometrical-optical, diffraction) done
end-to-end for selected cases; coverage of parameter space (wavelength, chopper angle) to be improved in context of instrument calibration
• Baffle design of FPU nearly finished; straylight analysis difficult
• Calibration sources conceptual design achieved
Details from N. Geis
PACS Instrument Overview 12
PACS IBDR 27/28 Feb 2002
• Detailed design of FPU structure in final phase.Structural problems solved.First part (“top optics”) in manufacturing.
• Delay for manufacturing from some interface problems and from late input– bolometer unit mounting interface
– electrical distribution board design
– detector array cable harness
– filter mounts
Details from J. Schubert and D. Kampf
FPU Status
PACS Instrument Overview 13
PACS IBDR 27/28 Feb 2002
13
PACS Instrument Overview 14
PACS IBDR 27/28 Feb 2002
• Environmental testing successful• Performance tests on both high and low-stress
modules with TIA: QE looks ok (high-stress: >30%)
• Design Changes– short-circuit “immunity” implemented in FM design
• Manufacturing Status– QM completed – but FEE integration outstanding– FM in production
• Problems– “pigtail” harness late and hard to fit in FPU– late readiness of FEEs
Details from H. Richter and D. Rosenthal
Photoconductor Arrays
PACS Instrument Overview 15
PACS IBDR 27/28 Feb 2002
Cryogenic Read-Out Electronics
• CREs have undergone complete redesign over the last two years
• Progress with new design from both, optimization of transistor geometry and of circuit design
• CQM run ‘032001’– design/layout improvement and local optimization of input
stage– successfully tested by IMEC and by CSL, working at MPE– will be used for detector module tests at LENS
• CQM run ‘102001’– essentially integrator type _024 (as 032001)
– evolutionary combination of additional features (4 Cint, increased dynamic range)
– for integration into QM detector modules, dice delivery 11/2001 Details from C. van Hoof
PACS Instrument Overview 16
PACS IBDR 27/28 Feb 2002
CRE032001 Performance
• Linearity : <3% non-linearity over >2V
• Cross talk between channels: <1% full range
• Noise, linearity, cross talk~ meet requirements
• Tests of CREs with detectors still ahead (early ’02)
16
PACS Instrument Overview 17
PACS IBDR 27/28 Feb 2002
Bolometer Arrays
• Two complete “blue” arrays mounted in cryostat at LETI for optical characterization
• Red arrays being assembled• Cold multiplexer/buffer noise (differential mode)
< 1 µV/Hz1/2
• Detection efficiency 80%(calculated) across PACSspectral bands
• Good tolerance to uncertaintyin background level shown bymodeling
Details from L. Rodriguez
PACS Instrument Overview 18
PACS IBDR 27/28 Feb 2002
3He Sorption Cooler
• 300 mK cooler development on track, good margin for 46h operation
Details from L. Duband
PACS Instrument Overview 19
PACS IBDR 27/28 Feb 2002
Chopper
• Status QM– Manufacturing at MPIA
started mid Oct 2001– Qualification tests started
January 2002– Delivery to MPIA/MPE/KT
planned for March 2002, but delayed due to pigtail delivery
• Problems– Damage of flex pivots in
lifetime model operation
Details from R. Hofferbert
PACS Instrument Overview 20
PACS IBDR 27/28 Feb 2002
Grating
• Diffraction Grating Sample received from Zumtobel GmbH (A),
under evaluationZeiss for FM manufacture as backup
• Actuator ordered from TU Berlin after successfulperformance test at 4K
• Position Sensor ordered from FARRAND after successfulbreadboard test of sensor at 4K
• Bearings coatings and preload control under evaluation
• Launch-lock prototype under fabrication
More information from E. Renotte
PACS Instrument Overview 21
PACS IBDR 27/28 Feb 2002
Warm Electronics Development
• BOLA – Mechanical design updated– Box thermal behavior modeling in progress– JFET modeling for effect of temperature on
performance in progress
• BOLC– Mechanical design BOLC updated (2 stacked boxes)– Analogue board prototype ready for performance test– Bolometer bias board (QM1) ready for design– “300mK” temperature control prototype designed– FPGA implementation of IEEE1355 under test at CSL– Most digital functions designed, except bolometer
sequencer
PACS Instrument Overview 22
PACS IBDR 27/28 Feb 2002
Warm Electronics Development• DEC/MEC
– DEC/MEC AVM Status• DSP and DEC simulator available / development on
schedule
– DEC/MEC EM Status• design and procurement ongoing, but validation with
representative hardware pending on mechanism simulators availability from partners
– DEC/MEC On-board Software Status• sequencer complete• communication 70% tested• mechanism control low-level S/W ~ 0%• MEC-to-DPU simulator completed: Virtuoso + OBS
emulated on a PC
– Successful operation of CRE with DEC prototype
• low noise + good linearity
Slopes @ 4K
2
2,5
3
3,5
4
4,5
5
500 510 520 530 540 550 560 570 580 590 600
sample
ou
tpu
t (
Vo
lts
)
CRE 03/01 @ 4K
PACS Instrument Overview 23
PACS IBDR 27/28 Feb 2002
Instrument Performance
• Instrument Requirements– Photometer– Spectrometer
• Instrument Model– Optical performance– Sensitivity budget
• optical transmission• background• detector performance
PACS Instrument Overview 24
PACS IBDR 27/28 Feb 2002
Photometer Performance Requirements
• Image quality– blur: telescope limited– distortion: ±1 pixel; alignment: <1/3 pixel
• Sensitivity (point source detection)– requirement: 5 mJy (5), 1h of integration– goal: 3 mJy (5), 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 25
PACS IBDR 27/28 Feb 2002
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 (5), 1h of integration– goal: 2x10-18 W/Hz1/2 (5), 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 26
PACS IBDR 27/28 Feb 2002
Optical Performance
• Optical design 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
PACS Instrument Overview 27
PACS IBDR 27/28 Feb 2002
(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.
Parameters of PACS Instrument Model(Present Best Estimate)
PACS Instrument Overview 28
PACS IBDR 27/28 Feb 2002
Background, NEP, Spectroscopic and Photometric Sensitivity
Performance requirements (or even goals) can be met
assumed detector QEs: 30% (spectroscopy); 80% (photometry) assumed detector NEPs: 5x10-18 W/Hz1/2 (spectroscopy); 10-16 W/Hz1/2 (photometry)