Neutron supermirror manufacturing
Yutaka YAMAGATA Team Leader, Ultra High Precision Optics Technology Team, RIKEN Center for Advanced Photonics (RAP), RIKEN
NNbar Collaboration Meeting Gothenburg 1 2015 Aug. 27-28 Outline • Neutron optics development at RIKEN – Neutron mirror using metallic substrate – Basic developments – Small ellipsoidal mirror – Segmented elliptic mirror for J-PARC BL-16 • Focusing Optics development for NNbar at ESS – Outline of optics – A manufacturing cost estimation – Reducing the cost and time – Summary
NNbar Collaboration Meeting Gothenburg 2 2015 Aug. 27-28 Neutron Focusing Mirror development
We have demonstrated the feasibility of focusing •Manufacturing Process of such ellipsoidal neutron small neutron scattering (mf-SANS) mirror with glass material is time-consuming task instrument at JRR-3. as it requires GRINDING process. Lower precision in profile and roughness Difficult to manufacture Large Scale Optics
3.5Qc Ellipsoidal Supermirror By using metallic substrate ( aluminum alloy etc.) manufacturing efficiency will be much better as it can be done with precision CUTTING process. In addition, handling easiness, robustness, radiation resistant
UPC (13h) Polished (24h) □ 50 mm
900mm ellipsoidal neutron 13 mm Peak-Valley 29.86 nm Peak-Valley 7.72 nm Focusing mirror. height height mf-SANS @ JRR-3 Roughness 4.14 nm Roughness 0.78 nm by Prof. Furusaka (Hokkaido Univ.) NNbar Collaboration Meeting Gothenburg 3 2015 Aug. 27-28 metallic substrate mirror • Advantages – Robust ductile material – Easier mechanical handling • Screw holes, positioning pins, fixture tabs can be used – Resistant to radiation and heat shock • Problem – Surface roughness limitation (polycrystalline structure) • Amorphous Ni-P plating solve this problem
NNbar Collaboration Meeting Gothenburg 4 2015 Aug. 27-28 Manufacturing Process ①Material preparation by ① end-mill Ra~several conventional milling micrometer
②Ｎｉ－Ｐ Plating ②③
single crystal Ra~serveral diamond cutting tens of nanometer ③ tool Ultraprecision cutting 10nm NiP-coated
④Polishing Pick-feed Shaper 100μm -10 nm Peak-Valley 29.86 nm Polishing pad Cutting for free-form height curved surface Roughness 4.14 nm Flat sample ④ □ 50 mm 10nm Abrasive Slurry
Ra ~several -10 nm 100 μm 13 mm Angstromes Peak-Valley 3.52 nm height NNbar Collaboration Meeting Gothenburg 5 Roughness 0.40 nm 5 2015 Aug. 27-28 Reflectivity test of flat test pieces
Flat sample 10nm □ 50 mm
-10 nm 100 μm Tested at Peak-Valley 3.52 nm Hokkaido height University Roughness 0.40 nm 13 mm Neutron Source (HUNS)
1 1 0.1
0.1 0.01 I
s 0.01 p Tested at KUR c 0.001 y t i s n e t 4
CN-3 n 0.001
i 10 Neutron 5 4 10 reflectometer 10 50 100 150 200 250 y 0.45mm ch 10 5 50 100 150 200 250 position channel 0.45 mm ch Diffuse scattering lower than 5Qc monochromatic coating On NiP substrate 10^-3.5 order ( noise limit) NNbar Collaboration Meeting Gothenburg 6 2015 Aug. 27-28 Manufacturing of small ellipsoidal mirror
Z
100mm Y X Cutting conditions 3-axis simultaneous machining
Machining method Shaper cutting Machine NAGASEi NIC 200 Positioning resolution 10 nm
Diamond tool R 2.0 mm
Depth of cut 5 μm - 3 μm - 1 μm Feed rate 2000 mm/min Temperature 23 ℃ Feed pitch 500 μm - 100 μm - 5 μm
NNbar Collaboration Meeting Gothenburg 7 2015 Aug. 27-28 7 Manufacturing result
Fabricated test piece (100 mm) Distribution of form error
Total manufacturing time: 1 week
(a) Aluminium substrate processed by precision cutting Form accuracy: 5 μm P-V and Neutron mirror processed by (b) eletroless nickel plating (Be available) and (c) ultraprecision cutting and polishing Surface rougness: 0.8 nm rms Surface roughness (Goal: <0.5 nm rms)
NNbar Collaboration Meeting Gothenburg After eletroless nickel plating process, the surface rougness get worse, while after the 1st polishing 8 process, the surface rougness is reduced to 0.72 0n1m5 A Ruga. .2 7-28 8 Focusing experiment at KUR CN-3 L = 2.5 m
Pinhole 0.65 m 0.25 m Slit Magnet Chopper
Neutrons RPMT
Ellipsoidal focusing mirror Goniometer stage Aperture: Ф1 mm (a=1250, b=7) (6-axis)
Rail Setup Jiang Guo, Shin Takeda, Shin-ya Morita, Masahiro Hino, Tatsuro Oda, Jun- Slit ichi Kato, Yutaka Yamagata, and Michihiro Mirror Furusaka, "New Fabrication Method for an ellipsoidal neutron focusing mirror with a metal substrate", Optics Express, Vol.22 No.20 DOI: 10.1364/OE.22.024666
NNbar Collaboration Meeting Gothenburg 9 focused neutron beam 20156 A-uag.x 2i7s- 2s8tage Mirror development for J－PARC beamlines
In collaboration with Photon and Quantum Basic Research Coordinated Development Program by MEXT Japan “ Fundamental understanding of friction and lubrication using neutron and muon” Project Leader: Dr. Hideki Seto (KEK) Member : KEK, Kyoto University Research Reactor Institute, Doshisha University, Kyushu University, Tohoku University
NNbar Collaboration Meeting Gothenburg 10 2015 Aug. 27-28 Large curved test piece: focusing mirror for BL-16 (J-PARC)
Focusing optics for BL-16 BL16 SOFIA 1. reflectometry： focusing at sample High Resolution Reflectometry position 2D position sensitive Detector → Higher flux on a small sample
Analysis of Material Interface and Structure 2. GISANS： focusing at detector position dynamics. → mesoscopic structure study on inter-plane Figures courtesy by KEK Dr. Yamada slit focusing mirror By using 1-D Ellipsoidal mirror, Incident angle range and intensity will be increased. sample 2D-detector
NNbar Collaboration Meeting Gothenburg 11 2015 Aug. 27-28 Fabrication method for multi-segmented mirror
When assembled While machining and coating Mirror segment Dummies for polishing
Positioning Pins
Mirror Base Alignment of mirror segments are controlled by positioning pins Segment size is limited by coating chamber capacity and Ultraprecision machine tool
NNbar Collaboration Meeting Gothenburg 12 2015 Aug. 27-28 Focusing and reflectivity test at BL-16 J-PARC
Side view Beam monitor ( MPSD, 1 mm res ) １D-mirror + slit ( 0.02 mm ) Moderator slit_1 Sample (0.05 or 0.2 mm) stage z slit_2 tilt slit_3 Detector
200 mm 200 mm
11000 mm 2150 mm 2150 mm 2000 mm
upstream S.Takeda, D-03, ICANS XXI (2014) downstream
NNbar Collaboration Meeting Gothenburg FWHM ~ 0.4mm 13 2015 Aug. 27-28 Summary of current mirror development at RIKEN
• A new manufacturing strategy of metallic neutron focusing mirror was proposed and basic manufacturing technology was established. • Quality of the focusing mirror was verified by flat test piece and small ellipsoidal focsing mirror. – Diffuse scattering < 10-3.5 – Focusing by ellipsoidal mirror – Profile figure error < 500nm p-v • 1D elliptic focusing mirror (550mm) with 2 segments were fabricated and tested at BL-16 (J-PARC) – Profile figure error was not sufficient due to corrosion – Surface roughness was acceptable (<0.3nm rms) but surface contamination caused reflectivity performance decrease – An improved version of 1D ellipsoidal mirror is now under manufacturing
NNbar Collaboration Meeting Gothenburg 14 2015 Aug. 27-28 Neutron-antineutron oscillation experiment at ESS
NNbar Collaboration Meeting Gothenburg 15 2015 Aug. 27-28 Optics Outline
•Additional optics are expected to Conversion enhance FOM. Target •Additional Optics 2 may interfere with ESS monolith. •Additional Optics 1 may be feasible.
z=200m Main Optics
Additional Optics1
Additional Optics2
z=40m z=10m Figure is expanded to z=5m radial direction by factor of 5 Target/Moderator z=2.6m NNbar Collaboration Meeting Gothenburg 16 2015 Aug. 27-28 A realistic drawing of optics -Additional Optics 2- 9 0 0 m m m m 0 0 8
NNbar Collaboration Meeting Gothenburg 17 2015 Aug. 27-28 Manufacturing time and cost estimation
Number of curved mirror pieces: 112 (circumuference division: 16, axial segments: 7)
Cost estimation: (NOT accurate)
mirror pieces: 3,000k JPY x112 Frames : 10,051k JPY Assembly : 10,051k JPY Total : 358,113k JPY (~2.6M euro) Manufacturing time: (1 curved mirror piece /week using current RIKEN facilities using pick-feed Curved mirror pieces shaper cutting.) not exceeding 3.1 years (70% duty ratio) 350mmx200mm
Too slow! Need to improve manufacturing speed!
NNbar Collaboration Meeting Gothenburg 18 2015 Aug. 27-28 How to improve manufacturing speed and cost?
• Using flat mirror segments – Combination of curved segments and flat segments
• Improve curved mirror manufacturing speed
NNbar Collaboration Meeting Gothenburg 19 2015 Aug. 27-28 Using flat mirror segments Horizontal projection
ΔW<= z/L * Dtarget
Vertical cross section
ΔL<= Δα/(dα/dz) Δα~ Dtarget/L
Width (Δw) and length (ΔL) limits of flat mirror segments can be estimated from target size
NNbar Collaboration Meeting Gothenburg 20 2015 Aug. 27-28 Estimated number of flat mirros
angle of number of number of number of circumfer mirror Δｗ circumfer axial z(mm) x(mm) ence ΔL(mm) segments (mm) ence mirrors division(de per division per meter g) section 2600 453 26 109.5 3.3 3.9 101.7 436 Additional 3000 486 30 101.8 3.5 7.9 125.9 816 Optics 2 4000 560 40 88.0 4.1 5.2 194.0 440 5000 624 50 78.5 4.6 3.7 271.6 312 6000 682 60 71.4 5.0 2.8 358.0 213 Additional 7000 735 70 66.0 5.5 2.2 452.7 132 Optics 1 8000 784 80 61.6 5.8 1.8 555.0 124 9000 829 90 57.9 6.2 1.5 664.8 116 10000 872 100 54.8 6.6 1.3 781.8 55 11000 912 110 52.1 6.9 1.1 905.6 52 12000 950 120 49.7 7.2 1.9 1036.2 100 14000 1020 140 45.8 7.9 1.5 1317.2 92 Main 16000 1085 160 42.6 8.4 1.2 1623.8 43 Optics 18000 1145 180 40.0 9.0 1.0 1955.6 40 20000 1200 200 37.7 9.6 2.2 2312.3 76 25000 1323 250 33.2 10.8 1.5 3312.2 66 30000 1428 300 29.9 12.0 1.1 4468.7 30 35000 1520 350 27.3 13.2 0.9 5787.7 27 40000
Total number of flat mirros 3170
NNbar Collaboration Meeting Gothenburg 21 2015 Aug. 27-28 Comparison with flat and curved mirror segments case
curved mirror size limited to: 350mmx200mm (Current RIKEN's manufacturing facility limitation)
•As z increases, required number of flat mirror segments decrease, while that of curved mirror segments increase. •There is a cross over point around 10m in this condition.
•Probably the most efficient way is to use curved mirror segments for front section and flat mirror segments to rear sections. •Cross over points may change depending on merit function. (manufacturing cost of flat or curved mirrors, maximum mirror size, assembly cost etc...) NNbar Collaboration Meeting Gothenburg 22 2015 Aug. 27-28 Improving the manufacturing efficiency of curved mirrors (1)
• Use of large ultraprecision lathe to manufacture curved mirror segments rather than pick-feed shaper cutting.
X Axis B Axis(Tool Holder) A number of such large ultraprecision lathe exist in Japan. Vacuum Z Axis Chuck
Max diameter 3.4m
Table Rotation Max height 240mm Toshiba Machine UTD-3400 •Use of larger, faster ultraprecision shaper cutting machine tool.
Toshiba Machine UMP65120D Maximum workpiece size: 1100mm x 600mm (6.6 times larger than RIKEN's facility) Maximum cutting speed : 15,000mm/min (15 times faster than RIKEN's facility)
NNbar Collaboration Meeting Gothenburg 23 2015 Aug. 27-28 Improving the manufacturing efficiency of curved mirror segments (2) • Tilted fly-cutting tool to manufacture curved mirror segments – An approximation by ellipsoid curve A detailed ray-tracing Precision simulation necessary if Milling ellipsoid is applicable. Feed spindle direction (1,000 to 3,000 rpm) Y
X Fly-cutting Z Tool cut cross section is ellipsoid
Machining efficiency is more than x100 times faster than pick-feed shaper cutting NNbar Collaboration Meeting Gothenburg 24 2015 Aug. 27-28 Summary for manufacturing methodology
• Current manufacturing method at RIKEN using pick-feed shaper cutting may be too slow to make all the optics. • Use of flat mirror segments to all section may be inefficient since quite large number of segments are necessary. • Compromise between curved and flat mirror segments may be a best solution. • Enhancing the manufacturing efficiency of curved mirror segments should be discussed further. – Use of large ultraprecision lathe, faster shaper cutting machine tool or use or tilted fly-cutting tool. • Those manufacturing options must be verified by accurate Monte-Carlo simulation and FEM structural analysis.
NNbar Collaboration Meeting Gothenburg 25 2015 Aug. 27-28 • Thank you for your kind attention!
NNbar Collaboration Meeting Gothenburg 26 2015 Aug. 27-28