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Prime Focus Imaging
Spectrograph
Status
• Engineering Status
Optics
Mechanical
Control System
• Management
Budget
Schedule
Oct 10, 2002
SSWG
1
Optics
•
•
•
•
•
•
Design Updates
Slit Throughput
VPH Grating Complement
Optomechanical
Concerns
Procurement plan
Oct 10, 2002
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2
Optics Design
• Updated camera and collimator to final indices
– ~ 20% image quality degradation;
• decrease manufacturing margin?
• relieve spec?
• Completed thermal design. Focus in camera
• Updated pupil placement and fold mirror position
for maximum NIR collimated beam
Details
• Fused silica -> fused quartz in common collimator
beam (for NIR)
Details
• Camera configuration update
Details
Oct 10, 2002
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3
Slit Throughput
• PDR: “max resolution 6250 overstated”. Used
median seeing 0.9 arcsec, not telescope image
• Model using seeing degraded to 37 deg ZD, actual
SAC, actual PFIS model
– In median seeing, a 1.25 arcsec slit will give 70%
throughput
– Resolution at a given grating angle reduced to 70%.
• Found can increase maximum articulation of
camera to 100 deg, increases max resolution 20%:
R = 5500 at 50 deg tilt, 1.25 arcsec slit
Oct 10, 2002
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Spectral Resolution vs. Throughput
Oct 10, 2002
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VPH Grating Complement
• VPH procurement in next 6 months, tradeoff
required: UV efficiency vs high resolution
efficiency
• Suggest: efficiency in UV for highest and lowest
density gratings; efficiency at high resolution for
other three
• Note that SALT can easily add VPH gratingsmagazine designed for swapout
Oct 10, 2002
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VPH tradeoff
Oct 10, 2002
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Optomechanical
• Largest PDR risk: optics, especially
optomechanical, underbudgeted
• Award subcontract for optomechanical to J. Alan
Schier
– optomechanics for Keck ESI, DEIMOS
– comfortable with fluid coupling, salt, solgel
• Tasks
– mounting tolerancing
– design, fabricate lens holders
– assemble lens groups
Oct 10, 2002
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Current concerns
• Coating strategy
– baseline: solgel on interior surfaces; hard elsewhere
– cost poorly defined
• Stress birefringence in collimator potentially
degrading polarimetric efficiency
– blanks: NaCl possible problem; lack of data
– 4 CaF2 blank costs may be increased
– investigating VPH and etalon effects
Oct 10, 2002
SSWG
Details
9
Optics procurement
• before CDR
–
–
–
–
third etalon (before year’s end to get good price)
fold flat/ coating
camera/ collimator blanks
grating blanks
• just after CDR
– camera/ collimator figuring
– waveplates, beamsplitter
– VPH gratings
Oct 10, 2002
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Structure/ Mechanisms
• Structure
– guide mount interface designed
– collimator assembly
• Mechanisms designed
–
–
–
–
waveplate
slitmask
grating. 6 grating complement
camera articulation.
• Will do full articulation in < 20 sec (enable PFIS
imaging mode as slitmask setup)
Details
• Articulate to 100 deg
Oct 10, 2002
SSWG
11
Control System
• Hardware
– generic mechanism test bed operational: use for
LabView learning curve, answering operational
questions for mechanism designs
– wiring architecture; box placement; cable harness
• Software
– actually operating hardware
– prototype client / server, scripting developed
– consistent with telescope architecture
Details
Oct 10, 2002
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Management
• Budget re-projection
• Schedule
Oct 10, 2002
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Cost-to-Completion Deltas
Base Dollars
PDR
’02 Q1
’02 Q2
’02 Q3
UW
$2,426,501
$2,616,194
$2,675,390
$2,814,391
Tot
$3,645,947
$3,835,640
$3,929,229
$4,068,574
Delta
$189,693
$93,589
$139,345
%
Cont
26
39
58
Oct 10, 2002
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14
Chief Deltas
• Q1-2 ($94K)
– CDR electrical engineering underestimate $15K
– SAAO Cryotiger, etc $25K
– US$ slowed inflation $50K
• Q2-2 ($139K)
– Drafting subcontract underestimate: $97K - $50K $20K = $27K. Control mech design schedule risk.
– Optomechanical subcontract: $220K - $50K - $20K =
$150K. Control optics technical/ schedule risk; biggest
PDR budget deficiency
Oct 10, 2002
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Prognosis
• Contingency use (58%) somewhat above expected (50%)
at this point, but still on track. Remaining deltas will be
much better known at CDR:
• Capital purchases. Preliminary RFQ’s on largest
– likely increases: CaF2 blanks; coatings
– likely savings: mechanisms/controls; lens fabrication; slitmask mill
• Schedule. Remaining contingency would cover 8 months
slip.
• When do we start spending contingency? At current rate,
Q1 ’04; at rate which would spend cap, Q4 ’03 (well after
CDR)
Oct 10, 2002
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Schedule
• Milestone: CDR 17 Mar, 2002
– slipped 2 months from PDR; mechanical design critical path
– recover: drafting/ engineering subcontract help
• Optical
– optomechanical subcontract kickoff
– procure blanks, issue pre-CDR RFQs
• Mechanical: 4 most complex mechanisms completed
• Control System: in progress
– hardware wiring diagram
– Labview design well under way
• Detail fabrication/ testing schedule in work this month
Details
Oct 10, 2002
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Done!
Oct 10, 2002
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Optics Details
Oct 10, 2002
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NIR Beam
20+/- 20 mm
NIR Beam (future)
Fold/ Dichroic
Fold
Articulation
Axis
Articulation
Pupil Axis
Focus
Visible Camera
Pupil
Collimator
Focal plane
Oct 10, 2002
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20
Filters
CCD
Focus
(Polarizing
beamsplitter
Camera
(Etalons)
Collimator
Side View (Fabry-Perot)
Optics
Configuration
(Waveplates)
Focal Plane
(Etalons)
CCD
Shutter
Fabry-Perot
(Grating)
VPH
Spectroscopy
(maximum
articulation)
Top View
Oct 10, 2002
SSWG
CCD
21
Camera
CaF2
Asphere
MAD = 0.45mm
• triplet modification
– CaF2 -> silica
– “aplanatic”
configuration
• reduced MAD on
asphere
• focus singlet +
triplet
NaCl
Silica
Asphere
MAD = 0.35 mm
Focus group
NaCl
Oct 10, 2002
SSWG
22
Birefringence Budget
• Unusual SALT configuration puts large glass path (17 cm!)
between waveplate and beamsplitter
• Stress birefringence at 45° to polarimetric axis causes
depolarization d ~ (π w)2 (w = biref in waves). d < 2% =>
w <~ 1/20 wave, biref/cm <~ 2-10nm/cm
• Have birefringence budget for
–
–
–
–
–
–
Fused silica, quartz: 1 -5 nm/cm
CaF2: 1-2 available at extra cost
NaCl: unknown. sample now being measured
Folding flat LLNL coating
VPH grating
Etalon
Oct 10, 2002
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Mechanical Details
Oct 10, 2002
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Completed Designs
gratings
slitmask
collimator
assembly
camera
articulation
Oct 10, 2002
waveplates
SSWG
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Camera Articulation
camera tube
gearbox/
motor
pinion
bearing
Oct 10, 2002
pneumatic
detent, 0.5 deg
spacing
SSWG
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Camera Support
Oct 10, 2002
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Grating Mechanism
pneumatic
insertor
linear stage
selector
6 gratings
grating
rotator
Oct 10, 2002
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Collimator Assembly
main collimator
group
slitmask magazine
guider feet
Oct 10, 2002
waveplates
SSWG
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Waveplate Mechanism
halfwave plate
quarterwave plate
blank
Oct 10, 2002
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Slitmask Mechanism - 1
linear stage
selector
magazine
pneumatic
insertor
mask in position
Oct 10, 2002
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Slitmask Mechanism - 2
pneumatic
extractor
Oct 10, 2002
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Control System Details
Oct 10, 2002
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Generic Mechanism
• Test Hardware
– candidate motor, encoders,
hall sensors, pneumatic
– motor drivers
– signal conditioner
– PXI motor card, I/O card
Oct 10, 2002
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LabView
• Hierarchical VI’s
• Commandable
from scripts
Controller
Controller
Controller
Stepper
Stepper
Pneumatic
Pneumatic
Pneumatic
Stepper Data
Home
Initialize
Controller Data
Port 1 On
Position
Port 1 Off
Index
Initialized
0
Enable
Pneumatics Data
Disable
Port 1
Moving
Enabled
Port
2 On
Set
Position
Kill
Port 2
Fwd Limit
Port 2 Off
Unkill
Killed
Homed
Fwd Limit
Rev Limit
Adjust Position
Home
Indexed
Rev Limit
Steps
0
Index
Quadrature Counts
0
Cable Sensor
0
Tab
Tab Control
Control
Oct 10, 2002
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Management Details
Oct 10, 2002
SSWG
36
ID
Task Name
1
Prime Focus Imaging Spectrograph
17
Phase 3 - Critical Design
1st Quarter
J
D
F
M
2nd Quarter
A
M
J
3rd Quarter
J
A
4th Quarter
O
S
D
1st Quarter
J
F
M
57%
18
System Review
19
Critical Optical Design
20
Image Motion Analysis
21
Throughput Resolution Analysis
s
Detail CDR Schedule
22
Mounting Sensitivity Analysis
s
100%
23
Final Collimator Design
24
Final Camera Redesign
25
Preliminary Thermal Analysis / Design
26
Final Thermal Analysis / Design
27
Prepare SPIE paper
28
Update Optical Design Document
29
RFP For Optomechnaical Design
100%
36
Fold Mirror Specification
100%
38
RFP For Camera / Collameter Optical Design
45
Grating Substrates Specification
48
Slit Mask Factory
51
Waveplates
54
Beam Splitters
57
Slit Viewers
60
VPH Grating
62
SR Gratings
64
Color Filters
66
N
100%
100%
78%
100%
3 wks
100%
3 wks
100%
3 wks
100%
19.4 wks
100%
5 days
100%
6.15 days
100%
65%
0%
0%
0%
0%
0%
0%
0%
0%
Critical Mechanical Design
54%
67
PFIS Structure
73
Critical Wave Plate Design
78
Critical Slitmask Design
81%
83
Mount Foot for Guider
62%
87
Critical Grating Design
93
Critical Articulation Design
99
Critical Filter Design
105
Focus Camera
0%
110
Critical Etalon Design
0%
112
Camera Tubes
115
Focus (Collimator) Design
0%
118
Critical Shutter Design
0%
121
Critical Polarizer Design
125
52%
86%
88%
54%
0%
0%
0%
Critical Control System Design
126
Generic Mechanism
132
Client / Server Design
133
User Interface Design
134
User Interface prototype
135
Wiring Diagram and Grounding & Switching Plan
145
Scripting Lannguage
148
Slitmask
151
Wave Plate
154
Other Mechanisms
162
Interlock Design Document (Whole)
163
Final Mechanism Control Design (Whole)
164
Power and Thermal Budget
165
Interface Control Documents
169
Prepare CDR Package
170
Critical Design Review
Oct 10, 2002
30%
100%
11.63 days
80%
17.44 days
0%
17.44 days
0%
26%
38%
0%
10%
0%
11.5 days?
100%
5.56 days
2.22 days
0%
0%
0%
10 days
SSWG
37
0%
1 day
0%