Transcript Kein Folientitel - INAF - Osservatorio Astrofisico di Catania

HIRDES UV Spectrographs
Phase-B1-Study
@WIC Moscow June, 2006
N. Kappelmann
History of the High Resolution Double Echelle
Spectrograph:
1998 –2006 (WSO/UV):
2000 - 2001
HIRDES Phase – A - Study
2002 - 2004
Efforts to finance a Phase - A2 - Study (ns)
2005 - 2006
Phase - B1 - Study
Design Criteria Phase A
Wavelength Coverage
: 103 – 320 nm
Spectral Resolution
: > 50.000
Simultaneous Coverage : as far as possible
Possibility to Observe Bright Stars
Improvement of FE of the MCP-Detector
High Resolution Double Echelle Spectrograph
(HIRDES)
VUVES : 102.8 – 175.6 nm
l/dl : 55.000
UVES : 174.5 – 310.0 nm
l/dl : 50.000
LSS
: 102.8 – 310.0 nm
l/dl : 320, spatial res: 1 - 2 arcsec
B1-Study-Priority:
Solving Interface
Questions
WSO/UV spacecraft interfaces, i.e. Optical
Bench Plate, External Instrument Plate
and Protective Case
Preliminary
Work Share: Germany
- Russia Work Share
UVES
VUVES
Optical Bench
R
R
Slits
G
G
Spectrometer Structure
G
G
Detector and FEE
G
G
Instrument Control Electronics
G
G
Power Supply (Low and high Voltage)
G
G
Optical Elements incl mounting pads
G
G
Calibration Units
G
G
Detector Mechanisms
G
G
Focus Mechanisms
R
R
Echelle Mechanisms - tbc
R
R
G (Architecture), R (coding)
G (Architecture), R (coding)
S/W (S/C data bus)
R
R
S/C Simulator EGSE
R
R
Instrument EGSE (Check Out, simulator)
G
G
OGSE (Alignment)
G
G
Optical Performance test facility
R
R
MGSE
G
G
R (Option: G+R)
R (Option: G+R)
G
G
S/W (Instrument controller)
Photometer (Monitor)
System Engineering
G: Germany; R: Russia
Design Criteria Phase B1
Wavelength Coverage
:
103 – 310 nm
Spectral Resolution
:
> 50.000
Simultaneous Coverage :
as far as possible
Possibility to Observe Bright Stars
Improvement of FE of the MCP-Detector
„Slit – Monitor“
Reduction of Mechanisms
High Resolution Double Echelle
Spectrograph (HIRDES)
VUVES : 102.8 – 175.6 nm
l/dl : 55.000
UVES : 174.5 – 310.0 nm
l/dl : 50.000
Mechanical Layout:
Three Independent
Spectrographs
Redundant Detectors
Grey Filter
Calibration Lamps
UBV Detectors
Tip/Tilt Mechanics
UV Spectrograph - In Field Fine Guidance with Lens
In field reflected at prism front surface towards focus mirror via lens onto fine guidance detector
VUV Spectrograph - In Field Fine Guidance
In field decoupled from 0th order reflection of grating via 2 mirrors onto fine guidance detector
Spectrometer Arrangement
B
50
B
LSS Spectrometer
11
LSS
00
120
A
37.
120 (
3x )
UV Spectrometer
3
UV
Spect r omet er
h
54
Y
0
52
0
Z
VUV
Spect r omet er
4
(
62
3x
)
Opt i cal bench I / F
see page 2
VUV Spectrometer
A
Spectrometers with Housing
Stand alone structure
Independent assembly
and alignment
Attachment of common
structure at optical bench
(S/C)
Trade Off
Active Aluminum Structure vs. Thermostable Structure
Phase A Baseline

Thermally unstable Aluminum structure

2 critical Focus Mechanisms ( Collimator Mirror , Echelle Grating)
 Compensation of thermal gradients, temperature change, (drift)
 Multi axes adjustment with very high accuracies required
Translatoric Accuracy
Travel Range
Accuracy
Repeatability
Rotational Accuracy
200 µm
20 arcsec
5 mm
2 arcsec
2 mm
1 arcsec
 Critical In Orbit Operation to find best focus position
Trade Off:
Thermomechanical Performance
Maturity
Costs
Candidate Materials
Aluminum
Composite materials
Ceramics
Thermostable CeSiC Structure

Required Spectral Resolution without Active Control of Optical
Elements
 Complex Collimator and Echelle Grating Mechanisms Skipped !!
Spectrometers without Housing
MCP Detector – Specification










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Wavelength Range
- UV
174.5 .. 310.0 nm
- VUV
102.8 .. 175.6 nm
Total gain
107 e- / Photon
Pulse height distribution
FWHM < 80% (TBC)
MCP pore diameter 6 µm (TBC)
Open area ratio (OAR)
80%
Length to diameter ratio
- 80:1 (first and second single MCP)
- 40:1 (third single MCP)
Active area
30x40 mm
Read out Method
Wedge and Stripe Anode (WSA)
Photocathode material
CsI, CsTe Depends on the wavelength range
Operational pressure < 1*10-5 mbar
Lifetime on ground
(TBD)
(after delivery)
Lifetime in Space
10 years (TBC)
Critical Components Design
Mirrors and Gratings
• Quartz Glas with Invar flexural mounts
• WFE: l/20 at l = 633 nm
• Surface Roughness: < 1 nm
• Coatings:
• UV : Al + SiO2
• VUV: Al + MgF2
• VIS: Al + SiO2 (Option: Au)
Isostatic Mirror Suspension
(ORFEUS Heritage)
Critical Components Design
Isostatic Suspension made from CFRP
(PACS heritage)
Invar Suspension with SS flexural Blades
(ORFEUS Heritage)
Critical Components Design
Vacuum Shutter – Mechanism Design
 Functionality
 Opening and closing of detector housing in vacuum
(Note: No window applicable due to optical performance)

Leakage Rate < 10-9 mbar • dm³ / sec
 Design Principle (ORFEUS heritage)

Sliding crank for aperture cover
 Kinematics

Travel Range 60 mm

Accuracy

Moving Mass << 1 kg (aperture cover)

Aperture
± 50 µm (equiv. 20 arcsec)
35 x 45 mm (MCP area + margin)
 Mechanism motor drive and equipment

Spur Gear and Worm Gear

Stepper Motor (Phytron)

Mechanical end stops
Servo Mirror – Mechanism Design
Functionality

Servo mirror steers main beam into redundant detector
Kinematics:

Translatoric movement of servo mirror (40 x 50 mm²)

Travel Range 60 mm

Accuracy
± 50 µm (equiv. 20 arcsec)

Moving Mass
100 g (mirror)
Mirror
Mechanism motor drive and equipment

Spur Gear and Worm Gear

Stepper Motor (Phytron)

Mechanical end stops
Spindle
MCP detector Housing
Nominal
Beam direction
nominal
Mechanical joint
between nominal and
redundant MCP
detector
MCP detector Housing
Redundant
Beam direction
redundant
Stepper Motor with
nominal and
redundant coils
Redundancy – System Concept
Result of redundancy concept trade-off
Subunit
Nominal
Redundant
Comments
ICU
x
x
Including telemetry/HK sensors
UVES MCP Detector
x
x
Including calibration means
VUVES MCP Detector
x
x
Including calibration means
UVES IFGS
x
-
Redundant electrical I/F
VUVES IFGS
x
-
Redundant electrical I/F
Mechanisms
x
x
Redundant coils and sensors only
Preliminary Test Matrix




Cross-switch function for HIRDES power
supply and data interface to S/C
Common control unit for UVES and
VUVES spectrometer
Cold redundancy
Switch over by relais command in case
of failure occurrence
(BB = breadboard, STM = Structural Thermal Mass Dummy, EQM = Engineering
Qualification Model, PFM = Proto Flight Model, FS refurbished STM/EQM Model
Preliminary Risk Assessment (top ranking risks)
Element
Risk Type
Risk Mitigation Strategy
MCP
Schedule risk due to
customized MCP
development and
technical risks (quantum
efficiency; Coatings)
 Selection of experienced stacks developer
(Hamamatsu);coating facilities, etc.)
 Use of FEE heritage partly available at IAAT
 Early MCP procurement & bread boarding
IFGS
Schedule risk due to
customized CMOS
development
 Selection of experienced CMOS developer (Fill
Factory)
 Adequate Subcontractor control;
Structural
materials and
Hybrid
Structure
(CeSiC; Invar,
Quartz Glas)
Technical risk due to
missing space
qualification
 Extensive technology programs performed by ECM
(ESA contract)
 Qualification to be performed in phase B
 Potential fallback: Space qualified C/SiC (Astrium F);
but not considered for baseline approach
Technology Study
Breadboard of New Electronic Concept
Breadboard of a CeSiC Optical Bench Structure
3,00E+05
Countrate [c/s]
2,50E+05
2,00E+05
1,50E+05
1,00E+05
5,00E+04
0,00E+00
0,00E+00
ORFEUS
5,00E+05
1,00E+06
Number of events [c/s]
1,50E+06
2,00E+06