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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
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ELT Studies in JapanMasanori 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 M.Iye/NAOJ SPIE Meeting @Glasgow, June 22, 2004
Some new initiatives • 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 size@0.6um=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
Z Y X Characteristics of Yoke Structure Tube (assumed mass : 750 tons) Yoke (Mass : 350 tons) 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
Weight increase rate of dehydrated CFRP due to moisture absorption in laboratory 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 CeramicJapan Ceratech/Taiheiyo Cement • 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 M.Iye/NAOJ SPIE Meeting @Glasgow, June 22, 2004
Long-term stability Zero-expansion Pore Free ceramic ZPF (Taiheiyo Cement) M.Iye/NAOJ SPIE Meeting @Glasgow, June 22, 2004
Zero-expansion Pore-Free Ceramic (ZPF)10ppb(at 0C), High elasticity, Pore-free, Cementable, Long term stability, Light weight structure, Polishable • Polished at NAOJ • roughness7nm 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
RMS 14nm surface roughness M.Iye/NAOJ SPIE Meeting @Glasgow, June 22, 2004
High Precision Grinding Machine (Nagase Integrex) # Work stage upto 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
1st 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
1st NC grinding w. rotation • #3000grit, 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 M.Iye/NAOJ SPIE Meeting @Glasgow, June 22, 2004
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