Presentation on theme: "M.Iye/NAOJ SPIE June 22, 2004 ELT Studies in Japan Masanori Iye (NAOJ) # ReOrganization of NAOJ+4 to NINS (as of Apr. 1, 2004) 3 times."— Presentation transcript:
M.Iye/NAOJ SPIE June 22, 2004 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 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 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 June 22, 2004 JELT Optics Layout
M.Iye/NAOJ SPIE June 22, 2004 Superb image quality: diffraction
M.Iye/NAOJ SPIE June 22, 2004 CAD Model: 30m telescope with 3 aspheric mirrors
M.Iye/NAOJ SPIE June 22, 2004 Nasmyth layout
M.Iye/NAOJ SPIE June 22, 2004 FEM analysis for JELT Journal EL Radial and Thrust Hydrostatic Bearing with Drive Yoke Structure AZ Thrust Hydrostatic Bearing with Drive AZ Track
M.Iye/NAOJ SPIE June 22, 2004 Characteristics of Yoke Structure Tube (assumed mass : 750 tons) X Y Z Yoke (Mass : 350 tons) Natural Frequency Analysis Model
M.Iye/NAOJ SPIE 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 June 22, 2004 Test on coated CFRP Cyanate CFRP: CTE 30ppb /C, light weight 1.5g/cm 3 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 June 22, 2004 Weight increase rate of dehydrated CFRP due to moisture absorption in laboratory NoMaterialCoating 1Epoxi NM-35 No 2Cyanate EX1515 No 3Cyanate NM-25 No 4Cyanate EX um 5Cyanate EX um 6Cyanate EX um
M.Iye/NAOJ SPIE June 22, 2004 CFRP Tests at Subaru enclosure Cyanate CFRP protected by Al foil was monitored for its weight variation at mass resolution during three months at Mauna Kea.
M.Iye/NAOJ SPIE 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 June 22, 2004 Zero-expansion Pore-Free Ceramic Japan 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 June 22, 2004 Physical characteristics of materials UnitCFRPC/SiCGlassZPF Young modulusE Densityρg/cm^ CTEαppm/K ConductivityΛ Heat Capacity Max Stress Roughness rmsnm7.414 Stiffness/massE/ρ Thermal stabilityΛ/α Size< 2m <8m<1m Costlowhigh medi
M.Iye/NAOJ SPIE June 22, 2004 Long-term stability Zero-expansion Pore Free ceramic ZPF (Taiheiyo Cement) EventDateSurface Errot (λ) Refl. As polishedJan % 1.5 year laterMay, Heated to 250 CJune, yearJan., yearMay,
M.Iye/NAOJ SPIE 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 roughness 7nm rms
M.Iye/NAOJ SPIE June 22, cm ZPF honeycomb mirror *Honey comb structure 2.4 => 1.7g/cm 3 (30% reduction) *Polished by NIKON to 1/12 λrms without a problem *No apparent print through of back structure
M.Iye/NAOJ SPIE June 22, 2004
RMS 14nm surface roughness
M.Iye/NAOJ SPIE 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 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 June 22, 2004
1 st 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 June 22, 2004
1 st NC grinding w. rotation #3000 grit, PV ＜ 3λ(over 65% area)
M.Iye/NAOJ SPIE June 22, st NC grinding in raster mode 1 st day(June 17 th) result: PRELIMINARY Apparently needs to optimize the grinding head shape, pitch, speed of raster 0.5mm 0.1mm
M.Iye/NAOJ SPIE June 22, 2004 Light Weight Structure
M.Iye/NAOJ SPIE June 22, 2004 Solid-State Sum Frequency Generating Sodium Laser
M.Iye/NAOJ SPIE 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.