Transcript PACS Test Facility Capabilities – Cryogenics and OGSE

Herschel Space Observatory
PACS Science Verification Review
MPE 22/23 June 2006
Future Tests:
PACS Test Facility Capabilities –
Cryogenics and OGSE
Gerd Jakob
GJ / MPE
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Herschel Space Observatory
PACS Science Verification Review
MPE 22/23 June 2006
Overview: Test Facility Status for PACS FM ILT
The set-up is basically as described in PACS Cryo Test Equipment and OGSE
Specification, PACS-ME-DS-002, Issue 1.1 (Status of CQM).
-> Document to be updated to FM status comprising following revisions:
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Test cryostat:
windows and filters
Test optics:
design features and alignment upgrade
H2O vapour cell:
new design
External blackbody:
improvements
Point source masks:
status
New molecular FIR laser source at LENS: first results
Test equipment:
schematic
GJ / MPE
2
Herschel Space Observatory
PACS Science Verification Review
MPE 22/23 June 2006
Test cryostat (OGSE 3)
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TC is equipped with 2 windows:
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Both windows are either equipped with:
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Quartz glass for optical alignment verification tests:
Transmission T~76% for λ>35μm
Or with:
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Window 1, diameter 25mm: integr. sphere entrance
Window 2, diameter 85mm: external focus entrance
PE foil, 1mm thick, for FM ILT:
T~80% for λ>35μm
Window 1 is equipped with:
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A manually operated cryo-shutter at ~90K with 2
positions:
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Transmission
A) open (T=100%) at reference position 0 mm
B) closed (T=0%) at reference position 30 mm
Window 2
Window 1
Window 2 is equipped with:
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A manually operated cryo-shutter at ~100K with 3
positions:
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A) FL_E-filter, T~85% for λ>52μm + quartz glass, 0.5mm
thick, T~76% for λ>35μm at reference position 8.5 mm
B) closed (T=0%) at reference position 98.5 mm
C) quartz glass, 0.5mm thick, T~76% for λ>35μm at
reference position 198.5 mm
2 fixed filters in series at ~6K (each 2 μm thick mylar
foil + Incornel coating): Transmission T~2.4% for
λ>35μm, respectively T~0.58% for both filters
GJ / MPE
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Test cryostat temperature levels:
L0 ~ 1.6K for ~7 days (13 LHe tankful)
L1 ~ 4.8K for ~2 days (70 LHe tankful)
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Test optics design
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aperture
4.2K
1. TUFIR input
integr. sphere
M10
P5
H
P
H
P2
M9
H hall sensor
GB gear box
MD motor drive
M mirror
A alignment mirror
P pupil
F focus
BB blackbody
CF cryogenic filter
CW cryostat window
T
MD3
M4
M5
M6
IF PC I/F
C control
T temperature read out
P position switch
1 integrating sphere w. light cone
1 external focus access
2 flip mirrors for optical path
selection (internal or ext. sources)
1 chopper wheel to chop between
BB1 and BB2: fchop_max@5K=0.457Hz
7 Cernox temperature sensors
light cone
P3
F5
CF
T
C
CW1
F4
CF
M8
T T
BB2
M7
P4
external
calibration
sources:
T
C
Temp. range: 5K – 80K
Absolute temp. accuracy:
+/- 20mK@20K; +/-35mK@50K
Thermal stability:
<+/-1.25mK@30K; <+/-5mK@50K
Power dissipation:
12.5mW@30K; 35mW@50K
shutter1
background
heater
integr.sphere
B3
G
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test optics housing
and baffling system
T C
point source mask
and X/Y translation
stage
GB2
P
T
MD2
C
chopper
wheel
C
2. TUFIR input
point source
F3
H
shutter2
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BB1
3. external BB:
extented or
point source
M1
H
P
T
M2
A1
A2
C
P1
M3
F2
GB1
flip P
mirror
C MD1 mech.1
T
PACS-FPU
4. water vapour
absorption cell
with BB
CW2
alignment with
auto collimator
CF
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PACS test cryostat
CF
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Principal design unchanged to CQM
ILT phase
2 cryogenic blackbodies (BB):
CF
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T
align.cube
align.device
test optics
rigid support
structure
F1
telescope
focus
Z
X
T T
T
77K
liquid helium
4.2K
T T
T
T
1.7K
77K
PACS test optics
G.Jakob 31.10.03
GJ / MPE
IF
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Herschel Space Observatory
PACS Science Verification Review
MPE 22/23 June 2006
Test optics alignment (1)
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Complete new optical alignment verification
started for FM campaign
TO internal alignment complete: optimized
imaging qualities and target positions
achieved with no vignetting:
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BBs and integrating sphere centered on Lyot
stop to 1% of diameter each
BB2
Ext.focus
entrance
(window2)
BB1
Test optics
Int.sphere
entrance
(window1)
PACS FPU
Test cryostat
GJ / MPE
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Test optics alignment (2)
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Internal and external focus positions
verified by use of LED array:
– best focus at +/-1mm from design
value
– Transverse position good to
+/-0.2mm
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Image quality:
Ext. focus
target
IM1
IM2
LED array
– < 3 µm wave front error (PACS)
– field distortion less than 1 blue
photometer detector pixel for the
total chopped PACS field of view
Test optics imager 1 and imager 2 with LED array
in telescope focus position and target in external
focus position
GJ / MPE
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PACS Science Verification Review
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Test optics alignment (3)
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1st cryogenic optical alignment verification test
at 5 Kelvin successfully performed
Cryostat equipped with test optics, PACS mass
and optical focus dummy
Autocollimator telescope with digital camera
aligned with cryostat
Additional prism optics mounted to observe
through both windows simultaneously
2nd cryogenic reproducibility test planned for
June / July
Preliminary results (after 1st run):
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Stability (300K / 5K) of test optics axis relative to
optical bench + PACS dummy:
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Prism optics
ACT
~ 0.1 mm in Y and Z direction (position)
< 30” angular
Stability (300K / 5K) of test optics + cryostat
optical bench relative to external window flange:
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cryostat
with test optics,
PACS mass and
optics dummy
~ 1 mm in +Y direction
~ 4 mm in -X direction (uncritical)
< 20” angular
All measured values within design specs.
GJ / MPE
Autocollimator telescope (ACT) aligned
with test cryostat, test optics and
reference prism optics
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PACS Science Verification Review
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H2O vapour cell
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New design with imaging optics, covering
the complete chopped PACS field of view:
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Ceramics heater with T=800K
Thermal stability ~+/-1K
Settling time ~1min
Cell will be equipped with (only) 1 PE
window (instead of 2 compared to CQM
ILT)
– Gap between cell and cryostat vented with
dry N2 gas
– Temperature und pressure data available
for housekeeping system
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Expected improvement (compared to CQM
ILT):
– 10% deep lines relative to measured
continuum for saturated H2O
– Improved line contrast of factor ~2-3
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Available for FM ILT to be mounted at test
cryostat window 2 position (external focus
entrance)
GJ / MPE
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PACS Science Verification Review
MPE 22/23 June 2006
External Blackbody
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Improved design with well
defined pin holes (point sources)
in a black painted surface (no
structures)
Available pin holes diameters:
0.45 / 0.7 / 1.0 / 1.5 / 2.0 / 4.0 /
10.0 / 15.0 / 25.0 mm
Temperature range 300K – 1000K
Thermal stability +/-0.25K
X/Y-stage position reproducibility
<20μm
30-50% improvement of contrast
(comp. to CQM ILT) by
implementation of N2 gas
environment
Design description in PACS-MEDS-003 will be updated
GJ / MPE
External blackbody mounted
on X/Y-stage at test cryostat
window 2
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MPE 22/23 June 2006
Point source masks
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Design description unchanged
from CQM ILT
See document PACS-ME-DS-003
issue 1 ‘OGSE External Point
Source Mask Specification’
Hot plate temperature up to
600K
All available hole patterns at
their nominal positions in the
FOV:
Hot plate assembled
with X/Y-stage at test
Cryostat window 2
•New: 30-50% improvement of
contrast by implementation of N2
gas environment
GJ / MPE
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Herschel Space Observatory
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MPE 22/23 June 2006
New Molecular FIR Laser Source at LENS (OGSE 4)
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LENS is building a new molecular
laser system:
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In early May 2006 a performance
demonstration at LENS in a pre-test
with MPE’s PACS detector set-up was
successful:
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CO2 pump laser with ~10 Watts
output power; bandwidth 1 MHz
FIR output power typically mW for
‘strong lines’ and μW for weaker lines
Bandwidth for a FIR line ~ MHz
Basic FIR lines are covering the PACS
spectral wavelength range
Det.
dewar
FIR
CO2
Two available lines were detected:
118.8 μm and 170.5 μm
For the FM ILT (Sept-Oct) the final
FIR source will be shipped to MPE to
be installed with the cryostat optics
GJ / MPE
Optical bench with CO2 laser and FIR laser
source during pre-test with PACS detector
module (integrated with blue test dewar)
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Herschel Space Observatory
PACS Science Verification Review
MPE 22/23 June 2006
New Molecular FIR Laser Source at LENS
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GJ / MPE
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FREQUENCY
(THz)
4.25167
2
3.10594
3
4
5
6
7
2.52278
2.25205
1.75753
1.34135
1.28832
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1.23478
9
1.18215
WAVELENGTH WAVENUMBER Expected output
(cm-1)
power
(m)
70.511638
141.821
mW
(no filter trans)
96.522408
103.603
µW
(no filter trans)
118.834107
84.151
mW
133.119600
75.120
µW
170.576394
58.625
mW
223.500
44.743
µW
232.7
42.9738
µW
(no det respo)
242.79
41.188
µW
(no det respo)
253.6
39.432
µW
Initial FIR methanol laser wavelengths
for PACS spectral calibration test;
further lines are feasible after successful
technical upgrade of the laser system
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Herschel Space Observatory
PACS Science Verification Review
MPE 22/23 June 2006
FIR laser lines, PACS RSRF and 0.5m air transmission
GJ / MPE
13
Herschel Space Observatory
PACS Science Verification Review
MPE 22/23 June 2006
New Molecular FIR Laser Source, beam input for FM ILT
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As successfully demonstrated
during the pre-test two different
optical set-ups are feasible for
PACS FM ILT:
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homogenous array illumination
with FIR source and integrating
sphere optics
single (or multi) pixel
illumination with FIR source
via external focus entrance
(point source)
‘point source’ motion across the
slicer
Improved air transmission
feasible by installation of N2 gas
vented light pipe optics
Laser power monitoring by
EGSE suggested
GJ / MPE
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Herschel Space Observatory
PACS Science Verification Review
MPE 22/23 June 2006
ILT Test Equipment Schematic
vacuum-pump
m3/h
He-pump
RS 232
Pumping unit
m3/h
CEA
300 K Harness
m3/h
IEEE/
RS 232
cryostat
temp diodes
Monitor 218
IEEE
cryostat
temp sensors
Monitor 1
TIC 304 M
IEEE
Monitor 2
TIC 304 M
XY Stage
gas
cell
Scanner
3716
TEST
OPTCS
4-300 K Harness
ext. BB
and
controller
CRYOBB1
IEEE
Hotplate
IEEE
CRYOVAC
PACS
FPU
Scanner
3716
Temp
Sensors
Monitor 218
BB1
Controller 370
BB2
Controller 370
IEEE
RS 232
IEEE
I/F
LENS I/F
Motor drive
electronics
IEEE
RS 232
1.7 K
LHe
IEEE
RS 232
LHe
4.2 K
RS 232
LN2
Testoptics
4 K Harness
RS 232
Pressure
Monitor
PKR 251
RS 232
GJ / MPE
SPU
testoptics
300 K Harness
4.2 K LHe-Level
Model 135
77 K LN2-Level
Model 186
DPU
PACSTestcryostat
77 K
1.7 K LHe-Level
Model 136
BOLC
DEC/MEC
CSL
300 K Harness
CRYOBB2
CRYOVAC
P
XY-Stage
Control
PC
"Labview"
RS 232
IEEE
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