Download ELT Studies in Japan Masanori Iye (NAOJ)

ELT Studies in Japan
Masanori Iye (NAOJ)
# ReOrganization of NAOJ+4 to NINS (as of Apr. 1, 2004)
3 times larger in budget and staff, increased flexibility?
# Future Planning WG for Opt/IR community
=> White Book (2004 summer)
# No Specific Budget for ELT R&D
=> request for 5 year R&D budget to JST/MEXT
# Yet, some studies are under way for a 30m JELT.
Reports on individual studies
Caution: including yet-personal perspectives!
M.Iye/NAOJ SPIE Meeting @Glasgow, June 22, 2004
Baseline Specification : Japan ELT
M1
F/1.5, segmented 30m,
CFRP/Glass/Ceramic :TBD
M2, M4
3 aspheric mirror system, adaptive M2,M4
Foci
2 (4) Nasmyth focal stations, No aberration
FOV
10 arcmin radius half circle, flat focal plane
λbands
0.39-5 micron
Instruments Opt Spectrograph, IR Spectrograph,
Cameras..
Enclosure
Diameter < 90m
M.Iye/NAOJ SPIE Meeting @Glasgow, June 22, 2004
Some new initiatives
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Optical design : 3 Aspheroc mirrors (Nariai/Iye)
Coated CFRP replication segment (Mitsubishi/NAOJ)
ZPF segment(Taiheiyo Cement/NAOJ)
High precision grinding machine (Nagase Integrex)
Light weight structure (Nagoya Univ., Mitsubishi)
Direct Drive Motor (Mitsubishi)
Segment support & adjust (Kyoto Univ., Melco)
ELID grinding (RIKEN)
LGS 188 element AO (NAOJ)
AO PSF Simulations (NAOJ)
Site Study(NAOJ)…
M.Iye/NAOJ SPIE Meeting @Glasgow, June 22, 2004
Optics: 3 Asph. Mirror Telescope (Nariai/Iye)
characteristics
/aberration free
/flat image plane
/M4 conjugate to
16km
/shorter telescope
/two arms on each
Nasmyth stage
4m DMs?
M.Iye/NAOJ SPIE Meeting @Glasgow, June 22, 2004
JELT Optics Layout
M.Iye/NAOJ SPIE Meeting @Glasgow, June 22, 2004
Superb image quality: diffraction [email protected]=10mas
M.Iye/NAOJ SPIE Meeting @Glasgow, June 22, 2004
CAD Model:
30m telescope with
3 aspheric mirrors
M.Iye/NAOJ SPIE Meeting @Glasgow, June 22, 2004
Nasmyth layout
M.Iye/NAOJ SPIE Meeting @Glasgow, June 22, 2004
FEM analysis for JELT
AZ Thrust
Hydrostatic
Bearing with
Drive
Journal
EL Radial and
Thrust
Hydrostatic
Bearing with
Drive
Yoke
Structure
AZ Track
M.Iye/NAOJ SPIE Meeting @Glasgow, June 22, 2004
Characteristics of Yoke Structure
Tube
(assumed mass : 750 tons)
Yoke
(Mass : 350 tons)
Z
Y
X
Natural Frequency Analysis Model
M.Iye/NAOJ SPIE Meeting @Glasgow, June 22, 2004
Segment Fabrication
・ New zero-expansion material for segments
1) coated CFRP : replica fabrication(Melco)
=> low cost, suppression of humidity
deformation
2) ZPF : grinding/polishing
Zero-expansion Pore-Free ceramic (Japan
Ceratech/ Taiheiyo cement)
・ Direct Grinding (Nagase Integrex)
no/little polishing => reduction of time/cost
M.Iye/NAOJ SPIE Meeting @Glasgow, June 22, 2004
Test on coated CFRP
• Cyanate CFRP:
CTE 30ppb /C, light weight 1.5g/cm3
• Cheaply replicated from mother mold.
• Affordable surface roughness
• Deformation for absolute dehydration 20ppm
with time scale of 500hrs
Water tight coating to give 100 times longer
time scale may give < 3ppb change in 1 hour.
*Need for static correction?
M.Iye/NAOJ SPIE Meeting @Glasgow, June 22, 2004
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Weight increase rate of dehydrated CFRP due to
moisture absorption in laboratory
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Material
Coating
1
Epoxi
NM-35
No
2
Cyanate
EX1515
No
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Cyanate
NM-25
No
4
Cyanate
EX1515
0.3um
5
Cyanate
EX1515
0.6um
6
Cyanate
EX1515
15um
M.Iye/NAOJ SPIE Meeting @Glasgow, June 22, 2004
CFRP Tests at
Subaru enclosure
• Cyanate CFRP protected
by Al foil was monitored
for its weight variation at
10-7 mass resolution
during three months at
Mauna Kea.
M.Iye/NAOJ SPIE Meeting @Glasgow, June 22, 2004
/Deformation due to the
variable moisture
content in 2 months
was 220ppb, 4 times
larger than thermal
deformation of ULE,
60ppb, for 20C
change.
=> Reducable by
optimizing plastic
material and/or
carbon content?
M.Iye/NAOJ SPIE Meeting @Glasgow, June 22, 2004
Zero-expansion Pore-Free Ceramic
Japan Ceratech/Taiheiyo Cement
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Thermally zero-expansion material (10ppb)
Stronger than glass for damaging (~ twice)
Machinable and polishable just like glass.
Aluminum deposition can be made.
Follows temperature variation 3 times faster than glass.
Acceptable surface roughness (a few nm rms).
Light weight structuring and sagged disk feasible
New facility plan for production of larger disks.
Somewhat less expensive than glass(?)
M.Iye/NAOJ SPIE Meeting @Glasgow, June 22, 2004
Physical characteristics of materials
Unit
Young modulus
Density
E
ρ
CTE
Conductivity
Heat Capacity
α
Λ
Max Stress
Roughness rms
Stiffness/mass
CFRP C/SiC Glass ZPF
120
400
90
150
g/cm^3 1.5
2.65
2.53 2.54
ppm/K
0.03
50
-
2.6
125
-
0.02
1.6
820
0.02
5.3
800
800
80
175
7.4
150
80
1
35
240
4
60
1700
< 2m
low
50
< 2m
high
80
<8m
high
260
<1m
medi
nm
E/ρ
Thermal stability Λ/α
Size
Cost
M.Iye/NAOJ SPIE Meeting @Glasgow, June 22, 2004
Zero-expansion Pore
Free ceramic ZPF
(Taiheiyo Cement)
Long-term
stability
Event
Date
Refl.
Jan. 2001
Surface
Errot (λ)
0.045
As polished
1.5 year later
May,2002
0.048
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Heated to 250 C June, 2002 0.050
2.0 year
Jan., 2003 0.052
-
M.Iye/NAOJ SPIE Meeting @Glasgow, June 22, 2004
87
%
Zero-expansion Pore-Free Ceramic (ZPF)
10ppb(at 0C), High elasticity, Pore-free, Cementable,
Long term stability, Light weight structure, Polishable
• Polished
at NAOJ
• roughness
7nm rms
M.Iye/NAOJ SPIE Meeting @Glasgow, June 22, 2004
30cm ZPF honeycomb
mirror
*Honey comb structure
2.4 => 1.7g/cm3 (30% reduction)
*Polished by NIKON to 1/12 λrms
without a problem
*No apparent print through of back
structure
M.Iye/NAOJ SPIE Meeting @Glasgow, June 22, 2004
M.Iye/NAOJ SPIE Meeting @Glasgow, June 22, 2004
RMS 14nm surface roughness
M.Iye/NAOJ SPIE Meeting @Glasgow, June 22, 2004
High Precision Grinding Machine
(Nagase Integrex)
# Work stage up to
4mx2m!
# Friction free
hydrostatic bearing
=> 10nm accuracy
1nm resolution
# Dynamic balancing of
spinning tool
Yamagata Industrial Research Inst.
M.Iye/NAOJ SPIE Meeting @Glasgow, June 22, 2004
High Precision Nagase Grinding Machine
• FMOS aspheric Schmidt
plate 28x24cm, loose
specification for fiber
imaging
• One-time grinding off
 Roughness 80nm
 Figure error 200nm
*metrology measurement
Iterative grinding with
optical interferometric
measurement has just tested
on 10cm ZPF.
M.Iye/NAOJ SPIE Meeting @Glasgow, June 22, 2004
M.Iye/NAOJ SPIE Meeting @Glasgow, June 22, 2004
st
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NC grinding experiments
• Three 10cm ZPF disks ground to R=30cm sphere
• ZPF1 rotated, #1500,
• ZPF2 rotated, #3000, a few hours work,
(smaller R at the center)
but surface error < 3 λover 65% of the surface
• ZPF3 raster scanned, 0.5mm then 0.1mm pitch,
overnight grinding => (grinding tracks visible)
figure error under evaluation.
Remember this is the result of first 5 days and
optimizations of parameters are yet to be seeked for!!!
M.Iye/NAOJ SPIE Meeting @Glasgow, June 22, 2004
M.Iye/NAOJ SPIE Meeting @Glasgow, June 22, 2004
1st NC grinding w. rotation
• #3000 grit, PV＜3λ(over 65% area)
M.Iye/NAOJ SPIE Meeting @Glasgow, June 22, 2004
1st NC grinding in raster mode
1st day(June 17th) result: PRELIMINARY
Apparently needs to optimize the grinding head shape, pitch,
speed of raster
0.5mm
0.1mm
M.Iye/NAOJ SPIE Meeting @Glasgow, June 22, 2004
Light Weight Structure
M.Iye/NAOJ SPIE Meeting @Glasgow, June 22, 2004
Solid-State Sum Frequency
Generating Sodium Laser
M.Iye/NAOJ SPIE Meeting @Glasgow, June 22, 2004
(Laser Diode pumped) Mode-locked
Nd:YAG Lasers
HR
HR
LD BOX
Mode Locker
LD
Nd:YAG
Output
Coupler
Nd:YAG
Mode Locker
1319 nm
LD
1064 nm
Output
Coupler
M.Iye/NAOJ SPIE Meeting @Glasgow, June 22, 2004
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SUMMARY
Experiencing to have a major reformation of
research organizations and is hoping to take this
chance to promote an ELT plan.
Has some expertise around Subaru Telescope
Inviting a few new industries for R&Ds toward
cost saving realization of ELTs.
Tentatively drawing a 30m ELT plan.
Applying for a 11M$ R&D budget to MEXT/JST
Is open for participating in international
collaboration to construct ELTs.
M.Iye/NAOJ SPIE Meeting @Glasgow, June 22, 2004