Development of mini-focusing small-angle neutron instruments (mfSANS) 1 Michihiro Furusaka Graduate School of Engineering, Hokkaido University
Hokkaido University - Electron linac based neutron source Tokai - J-PARC spallation neutron source - JRR-3 Reactor Tsukuba - KEK, - accelerator complex - KENS has been shutdown My locations 2
Collaborators 3 • M. Furusaka, F. Fumiyuki, A. Homma, T. Satoh , Y. Sasaki, Y. Okusawa, N. s t s Ishikawa i t n • Y. Kiyanagi, T. Kamiyama, K. Kamada e i c • s Grad. Sch. Eng., Hokkaido Univ. t n • M. Sugiyama, T. Satoh, M. Hino e m • u g KUR, Kyoto Univ. r t • P. Mikula n s i n r e I t • t a NPI, Czech c • H. Yoshizawa, M. Shibayama, H. Endoh, Y. Kawamura, T. Asami s n • o t r n ISSP Univ. Tokyo t • H. Takahashi, K. Fujita e u e m N p • o Grad. Sch. Eng., Univ. Tokyo l • K. Hirota, K. Ikeda, Y. Otake e v e d • RIKEN e • S. Ikeda, S. Naito, H. Shimizu, T. Otomo, T. Torikai, T. Ino, S. Satoh, J. Suzuki c i v e s • D r KENS, KEK o • K. Wada, S. Aoki t c o d • l National Center of Neuro Psychiatric a • H. Mochiduki, T. Yasuda c i d e • M Jyuntendo Univ. • S. Fujiwara • JAEA
Most of us know that neutron is a very powerful probe! 4
Large neutron facilities 5 • Big facilities like • ILL, Oak Ridge, Munich, NIST, JRR-3, KAERI, ANSTO, ... • ISIS, Luhan center, PSI, SNS, J-PARC • Bright future?
7 reasons not to use neutron 01
7 reasons not to use neutron 7 • I have to submit a proposal to get beamtime... • well, I don't know how to do it... • Where can I find information... • I heard it is difficult to obtain beamtime... • I have to wait for almost 1 year... • I don't know what kind of information we can get with neutron... • I don't know how to analyze data... • I looked for a book, but they are too difficult to understand... • I know how to use laboratory X-ray instrument, but...
Current situation 8 This is what we have now...
Large neutron facilities 9 • Machine time already oversubscribed • Not very suitable to train scientists/students • Difficult to install your own instrument • limited beamlines • everyday instruments are out of scope • Instruments for developing countries (cost, traveling) • Difficult to test new ideas.
NIST 30m SANS Huge and expensive SANS instruments 10 - Need a cold neutron source. - Only 1 instrument 32m at a guide-end. SANS-U@JRR-3
We have difficulties: 11 • Neutron facilities are expensive and not always available in developing countries • Neutron instruments are also expensive • Maintaining the instruments requires manpower and budget • Training young scientists/students are difficult • We desperately need next generation scientist!
In case of X-ray 12
X-ray 13 • Laboratory sources are available anywhere • Proper training methods established • Variety of books available • You can ask experienced people around. • If laboratory source is not appropriate, you can always use synchrotron radiation
Solution? 14
Solution: Many compact SANS instruments 15 Compact SANS units But How? incident beam
By the way, how about accelerator-driven laboratory-size neutron-source 16 s u o • RFQ accelerator + DTL ≈ 3-11MeV t u i q i b U n t e m u r t s n • Li or Be target i • Combined with: • many mfSANS modules, • mini-reflectometers, • mini-powder machines??
How to make compact instruments: Focusing is the key. 17 Focusing makes instrument compact! compact ≈ low cost Cf. Focusing gives us no-gain in intensity!
Ellipsoidal mirror focusing SANS Kamada et al. (Hokkaido Univ.) 18 • Ellipsoidal mirror Ellipsoidal Mirror • 1~10 mmø aperture Slit Mirror Sample Detector F1 F2 Shielding plate 1mm 10mm
Detector Lens/mirror Detector Sample Sample Focusing SANS instrument is Compact! 19 ■ Focusing ■ Same resolution/intensity t c a p m o c ≈ - Angular resolution Virtual ≈ D/L ≈ d/ ℓ Source - Intensity: I ∝ φ ⋅ d Ω i ⋅ d Σ d Ω ⋅ V sample ⋅ η ⋅ d Ω f d ℓ ■ Conventional point collimation D L
Focusing vs. Pinhole 20 q x q x q max Δ q x x -q max Small pinhole Focusing in real space q x q x q max Δ q x x x -q max
Reciprocal space k i Real space k f k i q' k f Focusing in k space 21 α Focusing beam 2 θ Detector "plane" α '= α 2 θ '=2 θ Sample 2 θ '
Mini-Focusing Small-Angle Neutron Scattering Instrument (mfSANS) @Hokkaido University 22 Time-of-flight focusing SANS
45MeV Electron Linac @Hokkaido University 23 Electron Linac Pulsed cold neutron source: • Best for developing Solid methane moderator neutron sources & devices • Flux ≈ 1/10,000 JRR-3@JAEA
Time Averaged Intensity compared 24 Factor 2-3 uncertainties 1.E+16 ILL 1.E+15 Port03 coupled JSNS intensity (n/cm2/s/str/eV) JSNS Coupled (cylindrical), simple Time Averaged neutron 1.E+14 model JSNS Decoupled H2 (Ed=1eV) JRR-3 1.E+13 JSNS Decoupled H2 (Gd Poison) SNS (2MW) 1.E+12 ISIS CH4 (160kW) KENS-CH4 1.E+11 KENS CH 4 KENS H 2 O KENS-CH4 1.E+10 KENS-H2O KENS-H2O 1.E+09 HU CH 4 HU H 2 O ILL-Cold 1.E+08 ILL-thermal 1.E+07 1.00E-04 1.00E-03 1.00E-02 1.00E-01 1.00E+00 1.00E+01 1.00E+02 E (eV)
Ellipsoidal Mirror 25 • Mirror length ： 900 mm • Major axis : 2 m • Minor axis ： 20 mm • Borated glass • Ni coating Made by JNOP
Detector Ellipsoidal mirror Beam port Data acquisition system Sample mfSANS at Hokkaido Univ. 26
1.5~2mm in other FWHM~1mm direction Fe 20nm Powder; Preliminary data 27 • 1mmφ aperture • cross sectional plot 1 0.1 0.01 0.001 10 � 4 � 10 � 5 0 5
Bovine thighbone, cross section SANS preliminary analysis 28 ./0&/12*3$4/5$) ()* ()* - ! !"#$%#!' I(q) ∝ q -3 mfSANS@H.U. !"#$%#+' 5mm φ I(q) ∝ q -2 !"#$"%&#' ! !"#$%#*' mfSANS@JRR-3 I(q) ∝ q -1 2mm φ 、 10mm φ !"#$%#)' !"#$%#(' !"#$%#&' Q min =0.002 ()* +, - ! !"#$%#& ! !"#$%#' ! !"#$%#! ! ~ 0.003 A -1 Okusawa et al
mfSANS@JRR-3/JAEA 29 Monochromatic neutron focusing SANS
Sample Detector Focusing Mirror Prototype focusing SANS@JRR-3 30 Ellipsoidal mirror 2.5 Q c supermirror ～ 2 . 5 m L ： 900mm W ： ≈ 20mm
Aperture mfSANS@JRR-3 31
Ellipsoidal mirror 32 • Mirror Parameters • 2.5 m between focal points • short radius 20 mm • ≈ 1/6 of an arc (66 deg) • 2.5 Qc supermirror coating
Direct beam profile 33 • 2 mm φ aperture • FWHM ≈ 2.5 mm
a t a d y r a n i m Ni powder 20nm i e l r P 34 • Q min = 5 × 10 -3 A -1 using 2mmø aperture. 100 I(q)~q -4 10 I(q) Direct 1 beam High-angle 0.1 detector bank 0.01 q/A -1 0.001 0.002 0.005 0.010 0.020 0.050 0.100
wider-angle scattering detectors at higher angle a t a d y r a n i m i e l r P 35 • 48 Linear position sensitive • 1/2 inch dia, 600 mm in length • GE made I(q) Water � 10 Water 散乱関数 I � Q � 0.01 0.001 10 � 4 10 � 5 10 � 6 Q � � � 1 � 0.02 0.05 0.10 0.20 0.50 1.00 0.05 q/A -1 0.6
Micro-phase separated block copolymer 36 mfSANS 0.100 2mm φ 、 2hrs 0.050 0.010 0.005 0.001 5 � 10 � 4 1 � 10 � 4 0.00 0.02 0.04 0.06 0.08 SANS-U 4m
Prism λ=λ 0 λ<λ 0 λ>λ 0 Strongly bent perfect crystals 37 • Bent perfect Si crystal Crystal Bender in fully asymmetric geometry CLBU5- 8-3.0 CLBP 695 5-8-20.0 ＣＰ ＬＳＣ SARPO4-25 • Si (111) １６ －５－ ＢＮ ６ ＲＳ６ ２５ ＢＵ ~３９ Ｕ６－ ．４ ２５ ＃６ ２６ Ｍ８ Ｐ＝ １ • Extremely small bent radius R ≈ 2m D2F-01L PS 2 SSCS SFGB8-120- J8- 6 F3-P 6-M3-T15- S5-Q5-SC56 • usually R ≈ 10~20m • 0.5 t × 120 × 20 mm slabs × 30, • long wavelength 5.8A • usually λ≈ 1~2A m 7 . s i 0 y i t v t i c ≈ e fl e r R , 5.8A y l t n e r r u C . w o l y r e v f o g n i k c a t s e h t e b y a M . m S e b l o r p i e h t c s i s a l r t s y r y c s t a l
Currently, poor monochromator performance 38 • Improved monochromator being tested Large Δλ / λ Pin hole Beam divergence ±10mrad → +80mrad neutrons deflector 1Qc~4Qc neutron mirrors Bent Perfect Si monochromator
High Resolution Detectors 39
Resistive wire type PMT +ZnS scintillator 40 • Li (n, α ); ZnS(Ag) scintillation Hirota, Satoh et al. • 3inch, 5inch PMT (RIKEN, KEK, NOP) • R2486-04 • Good resolution • <1mm • convenient system for optical device test. [ m [ mm [ m [ mm
Micro-strip Gas counters under development 41 • He(n, p) reaction • High reliability • "Grid lines" between anode and cathode • High resolution • 0.6mm FWHM • High counting rate: • 0.2-1MHz in future. • 10x - 100x 0.6mm FWHM K. Fujita,Takahashi et al. (Tokyo Univ.)
Ultra-long Micro-Strip Gas Counter 42 • MSTube ： 640 mm effective length • 1.6 ～ 3.2 mm position resolution • 0.2MHz; high count rate 640mm Local signal Global signal K. Fujita, H. Takahashi et al., Univ. Tokyo
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