Herschel Space ObservatoryPACS Science Verification ReviewMPE 22/23 June 2006 GJ / MPE 1 PACS Test...
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Transcript of Herschel Space ObservatoryPACS Science Verification ReviewMPE 22/23 June 2006 GJ / MPE 1 PACS Test...
GJ / MPE 1
Herschel Space Observatory PACS Science Verification ReviewMPE 22/23 June 2006
PACS Test Facility Capabilities – Cryogenics and OGSE
Gerd Jakob
Future Tests:
GJ / MPE 2
Herschel Space Observatory PACS Science Verification ReviewMPE 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:
• 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 3
Herschel Space Observatory PACS Science Verification ReviewMPE 22/23 June 2006
Test cryostat (OGSE 3)• TC is equipped with 2 windows:
– Window 1, diameter 25mm: integr. sphere entrance – Window 2, diameter 85mm: external focus entrance
• Both windows are either equipped with:– Quartz glass for optical alignment verification tests:
Transmission T~76% for λ>35μm
• Or with:– PE foil, 1mm thick, for FM ILT: Transmission
T~80% for λ>35μm
• Window 1 is equipped with:– A manually operated cryo-shutter at ~90K with 2 positions:
• A) open (T=100%) at reference position 0 mm• B) closed (T=0%) at reference position 30 mm
• Window 2 is equipped with:– A manually operated cryo-shutter at ~100K with 3 positions:
• 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
Window 1
Window 2
• Test cryostat temperature levels:L0 ~ 1.6K for ~7 days (13 LHe tankful) L1 ~ 4.8K for ~2 days (70 LHe tankful)
GJ / MPE 4
Herschel Space Observatory PACS Science Verification ReviewMPE 22/23 June 2006
Test optics design• Principal design unchanged to
CQM ILT phase• 2 cryogenic blackbodies (BB):
– 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
• 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
Z
X
T
C
T C
H
C
P
C
C
P
T
T
T
T
BB1
BB2
integr.sphere
MD3
chopperwheel
M6
M4
MD2
M1
M2
flipmirrormech.1MD1
align.cube
PACS-FPU
test optics housingand baffling system
liquid helium
test opticsrigid supportstructure
P1
F3
P2
P3
F4
P4
P5
CW2
CW1
M3
M5
M7M8
1. TUFIR inputintegr. sphere
2. TUFIR inputpoint source
3. external BB:extented orpoint source
4. water vapour absorption cell w ith BB
alignment with
externalcalibrationsources:
auto collimator
point source maskand X/Y translationstage
C
CF
CF
CF
telescopefocus
CF
C
T
P
c o n t r o lt e m p e r a t u r e r e a d o u t
p o s i t i o n s w i t c h
M D m o t o r d r i v eM m i r r o r
P p u p i lF f o c u sB B b l a c k b o d yC F c r y o g e n i c f i l t e rC W c r y o s t a t w i n d o w
P A C S t e s t c r y o s t a t
4 . 2 K7 7 K
P A C S t e s t o p t i c sG . J a k o b 3 1 . 1 0 . 0 3
F 1
7 7 K1 . 7 K
I F
I F P C I / F
PH
G B 1
G B 2
PHH
F 5
M 9
M 1 0
GB3T
T
T T
GB gear boxhall sensorH
T
A2A1
align.device
A alignment m irror
T T
T
TT
CF
sh
utt
er2
shu
tter
1
F2
TC
backgroundheater
aperture4.2K
light cone
GJ / MPE 5
Herschel Space Observatory PACS Science Verification ReviewMPE 22/23 June 2006
Test optics alignment (1)
• Complete new optical alignment verification started for FM campaign
• TO internal alignment complete: optimized imaging qualities and target positions achieved with no vignetting:
– BBs and integrating sphere centered on Lyot stop to 1% of diameter each
BB2 BB1
Ext.focusentrance(window2)
Int.sphere
entrance
(window1)
Test optics
PACS FPU
Test cryostat
GJ / MPE 6
Herschel Space Observatory PACS Science Verification ReviewMPE 22/23 June 2006
Test optics alignment (2)
• Internal and external focus positions verified by use of LED array:– best focus at +/-1mm from
design value– Transverse position good to
+/-0.2mm
• Image quality: – < 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
IM2
Ext. focustarget
IM1
LED arrayLED array
GJ / MPE 7
Herschel Space Observatory PACS Science Verification ReviewMPE 22/23 June 2006
Test optics alignment (3)• 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):– Stability (300K / 5K) of test optics axis
relative to optical bench + PACS dummy: • ~ 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:
• ~ 1 mm in +Y direction • ~ 4 mm in -X direction (uncritical)• < 20” angular
– All measured values within design specs.
Autocollimator telescope (ACT) aligned with test cryostat, test optics and reference prism optics
ACT
Prism optics
cryostatwith test optics,PACS mass and optics dummy
GJ / MPE 8
Herschel Space Observatory PACS Science Verification ReviewMPE 22/23 June 2006
H2O vapour cell• New design with imaging optics,
covering the complete chopped PACS field of view: – 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
• Expected improvement (compared to CQM ILT):– 10% deep lines relative to measured
continuum for saturated H2O– Improved line contrast of factor ~2-3
• Available for FM ILT to be mounted at test cryostat window 2 position (external focus entrance)
GJ / MPE 9
Herschel Space Observatory PACS Science Verification ReviewMPE 22/23 June 2006
External Blackbody
• 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-ME-DS-003 will be updated External blackbody mounted
on X/Y-stage at test cryostatwindow 2
GJ / MPE 10
Herschel Space Observatory PACS Science Verification ReviewMPE 22/23 June 2006
Point source masks• 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:
•New: 30-50% improvement of contrast by implementation of N2 gas environment
Hot plate assembled with X/Y-stage at testCryostat window 2
GJ / MPE 11
Herschel Space Observatory PACS Science Verification ReviewMPE 22/23 June 2006
New Molecular FIR Laser Source at LENS (OGSE 4)
• LENS is building a new molecular laser system:
– 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
• In early May 2006 a performance demonstration at LENS in a pre-test with MPE’s PACS detector set-up was successful:
– 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 Optical bench with CO2 laser and FIR laser
source during pre-test with PACS detectormodule (integrated with blue test dewar)
CO2FIR
Det.dewar
GJ / MPE 12
Herschel Space Observatory PACS Science Verification ReviewMPE 22/23 June 2006
New Molecular FIR Laser Source at LENS# FREQUENCY
(THz) WAVELENGTH
(m) WAVENUMBER
(cm-1) Expected output
power 1 4.25167 70.511638 141.821 mW
(no filter trans) 2 3.10594 96.522408 103.603 µW
(no filter trans) 3 2.52278 118.834107 84.151 mW 4 2.25205 133.119600 75.120 µW 5 1.75753 170.576394 58.625 mW 6 1.34135 223.500 44.743 µW 7 1.28832 232.7 42.9738 µW
(no det respo) 8 1.23478 242.79 41.188 µW
(no det respo) 9 1.18215 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
GJ / MPE 13
Herschel Space Observatory PACS Science Verification ReviewMPE 22/23 June 2006FIR laser lines, PACS RSRF and 0.5m air
transmission
GJ / MPE 14
Herschel Space Observatory PACS Science Verification ReviewMPE 22/23 June 2006
New Molecular FIR Laser Source, beam input for FM ILT
• As successfully demonstrated during the pre-test two different optical set-ups are feasible for PACS FM ILT:
– 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 15
Herschel Space Observatory PACS Science Verification ReviewMPE 22/23 June 2006
ILT Test Equipment Schematic
LHe4.2 K
PACSFPU
LN2
77 K
1.7 KLHe
I / F
TESTOPTCS
CR
YO
-B
B1
CR
YO
-B
B2
PACS-Testcryostat
cryostattemp diodesMonitor 218
IEE
E/
RS
232
cryostattemp sensors
Monitor 1TIC 304 M
IEE
E
Monitor 2TIC 304 M
IEE
E
4.2 K LHe-LevelModel 135
IEE
E
1.7 K LHe-LevelModel 136
IEE
E
77 K LN2-LevelModel 186
IEE
E
PressureMonitor
PKR 251
RS
232
Motor driveelectronics
RS
232
TempSensors
Monitor 218
IEE
ER
S 232
BB1Controller 370
IEE
ER
S 232
BB2Controller 370
IEE
ER
S 232
BOLC
DEC/MEC
DPU
SPU
XY-StageControl
RS
232
m3/hm3/hvacuum-pump m3/h
Pumping unit He-pump
ext. BBand
controller
gascell
Hot
plat
e
LENS I/F
PCEA300 K Harness
CSL300 K Harness
testoptics300 K Harness
Scanner3716
Scanner3716
PC"Labview"RS 232IEEE
CR
YO
VA
CC
RY
OV
AC
RS
232
XY Stage
Testoptics4 K Harness
4-30
0 K
Har
ness