Oct 22, 2007 SSWG #18 UKZN 1
Robert StobiePrime Focus Imaging
SpectrographStatus
• Optics repair• Schedule• Status of other fix and improvement projects• Budget
Oct 22, 2007 SSWG #18 UKZN 2
C o a tin g s
C am era C o llim a to r
M g F / so lg e l2
M g F 2
M u ltilay e r
C aF 2
S ilic a
Optics Reprise: Throughput/ Ghosts
• Three problems– Yellow ghost due
to coating problem on dewar window
– Grey loss in camera triplet
– UV loss in contaminated lens fluid of four multiplets
• Instrument removed (Nov 2006), optics shipped to Pilot Group in Calif (Dec)• Disassembled into multiplets, throughput measured by monochromator (Feb - Apr 2007):
Oct 22, 2007 SSWG #18 UKZN 3
#1,2: fixed
• Field flattener (ghost). Bad coating polished off by Janos, new coating applied by Spectrum Thin Films (with new moisture repellant overcoat). Satisfactory.
• Camera triplet contact. Backed off pressure, contact and grey loss vanished, has not reappeared.
Oct 22, 2007 SSWG #18 UKZN 4
#3: Repair (still) "in work"
• Found absorption in lens fluid (Cargille LL5610) due to polyurethane expansion bladders, and (lesser extent) viton O-Rings
• Original plan (May - July): flush/ replace fluid with LL3421 (viton compatible), replace bladder with polyethylene– Can be done without disassembling
multiplets, although index slightly low
• Plan A: Did not work– fluid gaps too small, some could not
be flushed
– ethanol flushing agent sometimes fogged test NaCl pieces
0%
20%
40%
60%
80%
100%
120%
200 300 400 500 600 700
N ew F lu id
F ld Lens
C oll Trip
C oll D B lt
C am Q uart
C am Trip
Fluid Sample Transmission
0%
20%
40%
60%
80%
100%
120%
200 300 400 500 600 700
N ew F lu id
F ld Lens
C oll Trip
C oll D B lt
C am Q uart
C am Trip
G oodm an #1
G oodm an #2
Fluid Sam ple Transm ission
Fluid + Material Experiments
0%
20%
40%
60%
80%
100%
120%
200 300 400 500 600 700
Wavelength (nm)
N ew F lu id
Polyurethane Tubing
SylG ard 184
RTV Sealant 730
Sulfuric Anodizing
Brass
P lastic Syringe
Viton
Polyurethane b ladder
Oct 22, 2007 SSWG #18 UKZN 5
Plans B, C (and D)• Plan B: Disassemble multiplets, clean, replace expansion
polyurethane bladders and viton O-rings– Back to LL5610 fluid (better index match) except for
Collimator Field Lens and Triplet: LL3421 a better choice for common NIR beam
• (Aug - Sept) Four of five multiplets repaired. During reassembly of the last, two surfaces of first CaF2 element in collimator triplet ("OL5") damaged by technician error!
• Plan C: Recovery – use existing spare blank (thanks to CDR panel!)– Pilot to cover blank, figuring, coating costs– figuring underway by TORC– considering Lick Obs hardened solgel coating– 3 - 6 month delay– Plan D (in case this one breaks!): regrind damaged element
Oct 22, 2007 SSWG #18 UKZN 6
Throughput – Collimator
• Field Lens repair: UV loss was very small - repaired as precaution
• Triplet repair: interrupted by accident: projection shown
• Doublet repair– UV loss gone except slight
dip at 350 nm
– ~10% grey loss still seen
320 0320 1.1
Field lens Assembly
0.0
0.2
0.4
0.6
0.8
1.0
200 300 400 500 600 700 800 900
W avelength (nm )
Tra
nsm
issi
on
0 .0
0.2
0.4
0.6
0.8
1.0
Re
flect
ivity
T M onoC h
T laser
T a fter fix
R W itness
O L3
0.0
0.2
0.4
0.6
0.8
1.0
200 300 400 500 600 700 800 900
W avelength (nm )
Tra
nsm
issi
on
0 .0
0.2
0.4
0.6
0.8
1.0
Re
flect
ivity
T M onoC h
R W itness
O L4
0.0
0.2
0.4
0.6
0.8
1.0
200 300 400 500 600 700 800 900
W avelength (nm )
Tra
nsm
issi
on
0 .0
0.2
0.4
0.6
0.8
1.0
Re
flect
ivity
T M onoC h
R W itness
Collimator Triplet
0.0
0.2
0.4
0.6
0.8
1.0
200 300 400 500 600 700 800 900
W avelength (nm )
Tra
nsm
issi
on
0 .0
0.2
0.4
0.6
0.8
1.0
Re
flect
ivity
T M onoC h
T P ro jected
R W itness
Collimator Doublet
0.0
0.2
0.4
0.6
0.8
1.0
200 300 400 500 600 700 800 900
W avelength (nm )
Tra
nsm
issi
on
0 .0
0.2
0.4
0.6
0.8
1.0
Re
flect
ivity
T M onoC h
T laser
T a fter fix
R W itness
R laser
Collimator
0.0
0.2
0.4
0.6
0.8
1.0
200 300 400 500 600 700 800 900
W avelength (nm )
Tra
nsm
issi
on
0 .0
0.2
0.4
0.6
0.8
1.0
Re
flect
ivity
T M onoC hT laserT a fter repairT P ro jectedR W itness
Oct 22, 2007 SSWG #18 UKZN 7
Throughput - Camera/ Spec
• Quartet Repair. Looks good.
• Triplet Repair
– surface contact fix remedies grey loss
– fluid repair improves UV, leaves ~15% loss at 320 nm
• Project visible ~5% below FPRD spec, 30% low at 320 nm
320 0320 1.1
Field Flattener
0.0
0.2
0.4
0.6
0.8
1.0
200 300 400 500 600 700 800 900
W avelength (nm )
Tra
nsm
issi
on
0 .0
0.2
0.4
0.6
0.8
1.0
Ref
lect
ivity
T M onoCh
T after recoat
R W itness
R laser
R G hosts
Camera Quartet
0.0
0.2
0.4
0.6
0.8
1.0
200 300 400 500 600 700 800 900
W avelength (nm )
Tra
nsm
issi
on
0 .0
0.2
0.4
0.6
0.8
1.0
Ref
lect
ivity
T M onoCh
T after repair
R W itness
Camera Singlet
0.0
0.2
0.4
0.6
0.8
1.0
200 300 400 500 600 700 800 900
W avelength (nm )
Tra
nsm
issi
on
0 .0
0.2
0.4
0.6
0.8
1.0
Ref
lect
ivity
T M onoCh
R W itness
Camera Triplet
0.0
0.2
0.4
0.6
0.8
1.0
200 300 400 500 600 700 800 900
W avelength (nm )
Tra
nsm
issi
on
0 .0
0.2
0.4
0.6
0.8
1.0
Ref
lect
ivity
T M onoCh
T after contact fix
T after R epair
R W itness
Camera
0.0
0.2
0.4
0.6
0.8
1.0
200 300 400 500 600 700 800 900
W avelength (nm )
Tra
nsm
issi
on
0 .0
0.2
0.4
0.6
0.8
1.0
Ref
lect
ivity
T M onoCh
T after repair
R W itness
Spectrograph
0.0
0.2
0.4
0.6
0.8
1.0
200 300 400 500 600 700 800 900
W avelength (nm )
Tra
nsm
issi
on
0 .0
0.2
0.4
0.6
0.8
1.0
Ref
lect
ivity
T M onoCh
T after repair
T P rojection
FPRD M in T
R W itness
Oct 22, 2007 SSWG #18 UKZN 8
Remaining UV loss - multilayer coatings?
• Notice that all elements having Spectrum Thin Film multilayer coatings (including singlet field flattener after recoat) have "ripples", one in the UV.
• Suspect absorption effect, not caught with reflectivity witness
• Small effect not worth risk and cost of disassembly, polish off coat, recoat, etc
• Effect may also be in SALTICAM
• If true, should not be seen in repaired collimator triplet (solgel/ MgF2)
Multilayers after fluid repair
0.0
0.2
0.4
0.6
0.8
1.0
200 300 400 500 600 700 800 900
Wavelength (nm )
Tran
smis
sio
n
C oll D bltC am Q rtC am TripF lattener
Oct 22, 2007 SSWG #18 UKZN 9
Comparison with on-sky
• Projected improvement
– UV 10x (5x so far)
– Visible 10 - 30%
Optics Throughput
0%
20%
40%
60%
80%
100%
300 400 500 600 700 800 900
Wavelength (nm)
% C
DR
Go
al
EG 21 S litless Spec
47 Tuc Im aging
EG 21 Im aging Burst
M ar-Jun Im aging Burst
M onochrom ator
P ro jected
Oct 22, 2007 SSWG #18 UKZN 10
Repair Schedule
Schedule
• With departure of Eric Burgh, new UW optics reintegration support team: Alan Shier (Pilot Group), Marsha Wolf (NIR project)
• Reintegration schedule– No earlier than: 7 Feb - 31 Mar
– With 3 month contingency: 1 May - 23 June
Oct 22, 2007 SSWG #18 UKZN 11
RSS Fixes/ Improvements
• Slitmask mechanism– severe reliability problems due to difficulty of aligning magazine,
carrier, and focal plane chute– redesigned, rebuilt; sensor electronics board iteration
• Grating stage flexure– out-of spec flexure perpendicular to dispersion– repaired current grating stage; purchased new, improved one
• Etalon flexure– ring centers do not flex the same: dual etalon difficulty– improve etalon "seat". Done
• Fix guider interference (limits field): Done• Improve baffling
– moving baffle damage, maintainability. Material received– payload/ instrument interface. Material received; design complete
• High level software. Design Complete; coding in progress• Detector fast readout modification (last SSWG). Done
Oct 22, 2007 SSWG #18 UKZN 12
Cost to Completion
• Does not include ~$40K repair overrun due to additional work disassembling multiplets ("Plan B")
• Replacement of damaged element OL5 borne by Pilot Group
• Still predicting CTC ~20% over CDR budget
$-
$1,000,000
$2,000,000
$3,000,000
$4,000,000
$5,000,0002002 2003 2004
PD
R
CD
R
De
liver
y
E st C ost to C om pletion
U W
SAAO
R U
Tota lExpenditures
Baseline
20% Budgeted Reserve
no
w
2005 2006 2007