– 1968IBR-1 (1 – 6 kW) 1969 – 1980 IBR-30 (15 kW) 1981 – 1983IBR-2 (100 – 1000 kW) 1984 – 2004IBR-2 (1500 – 2000 kW) tit Neutron scattering in condensed matter research. 20 years of regular studies at the IBR-2 pulsed reactor. Anatoly M. Balagurov Condensed Matter Department of Frank Laboratory of Neutron Physics, JINR

2 1 st -sp Diffraction TOF patterns: in the past and at present. Si diffraction pattern, measured at the IBR Si diffraction pattern, measured at the IBR

3 Tem Time-of-Flight (TOF) technique at pulsed neutron source Alternatives: Steady state source (reactor)W = 10 – 100 MW, const in time. Pulsed source (reactor / accelerator)W = 10 – 2000 kW, pulses in time. These two types are generally considered to be complimentary! At pulsed neutron source TOF technique is used in a natural way! Neutrons are separated in energy after traveling over a fixed path (L), permitting neutrons of many different energies and wavelengths to be used for experiments. Flight path Source pulseTime Low energyHigh energy

4 IBR-2 Active core IBR-2 pulsed reactor (1984 – present) The IBR-2 parameters FuelPuO 2 Active core volume22 l Coolingliquid Na Average power 2 МW Pulsed power1500 MW Repetition rate5 s -1 Average flux8·10 12 n/cm 2 /s Pulsed flux5·10 15 n/сm 2 /s Pulse width (fast / therm.)215 / 320 μs Number of channels14 Movable reflector

5 Diffr.-IBR2 The IBR-2 pulsed reactor for condensed matter research. Comparison with other pulsed sources. Source Parameter IBR-30 JINR IBR-2 JINR ISIS RAL, UK SNS ORNL, USA Status Power, kW Pulse width, μs Frequency, s

6 Diffr.-IBR2 The IBR-2 pulsed reactor for condensed matter research. Comparison with other pulsed sources. Intensity / Counting rate I ≈ Φ 0 · S · Ω/4π [n/s] ≥ 10 6 n/s DN-2, IBR-2:Ω ≈ 0.2 sr GEM, ISIS:Ω ≈ 6.0 sr Φ 0 – neutron flux at a sample, 10 7 n/cm 2 /s S – sample area, 5 cm 2 Ω – detector solid angle, 0.2 sr

7 Diffr.-IBR2 The IBR-2 pulsed reactor for condensed matter research. Comparison with other pulsed sources. R = [(Δt 0 /t) 2 + (Δ  /tg  ) 2 ] 1/2 Resolution Δt 0 – pulse width, Δ  - geometrical uncertainties, t ~ L · λ – total flight time,  – Bragg angle. IBR-2: Δt 0 ≈ 320 μs. ISIS: Δt 0 ≈ 20 μs. TOF component in resolution function is not very important for: SANS, reflectometry, single crystal diffraction, magnetic diffraction… For high resolution experiment we use the Fourier technique ! R ≈ 0.01, DN-2. R ≈ 0.003, GEM.

8 chopper High Resolution Fourier Diffractometer 0.7 mm Rotor Stator Transmission function Binary signals Fourier chopper: N=1024 V max =9000 rpm Ω = 150,000 s -1 S beam =3x30 cm 2 R(t) R(t) ≈ g(ω)cos(ωt)dω, Δt 0 ≈ 1/Ω = (Nω m ) -1 ≈ 7 μs

9 HRFD HRFD – High Resolution Fourier Diffractometer at the IBR-2 pulsed reactor In collaboration between: FLNP (Dubna), PNPI (Gatchina), VTT (Espoo), IzfP (Drezden) IBR-2 Fourier chopper

10 high-low Diffraction patterns measured with high and low resolution HRFD  d/d  DN-2  d/d  0.01

11 HRPD-HRFD Al 2 O 3 standard measured at ISIS and IBR-2 For V=11,000 rpm & L=30 m R t = (d=2 Å) The utmost TOF resolution of HRFD

12 1 st -sp Diffraction TOF experiments with sapphire anvil high- pressure cells (collaboration with “Kurchatov Institute”) Diffractometer DN-12 at the IBR-2 high-pressure Sapphire anvil high-pressure cell, Р up to 7 GPa (cylinder 48 mm  x 164 mm height).

13 Mono-DKDP 2D cross-section of (400) spot of KD 2 PO 4 single crystal measured by 1D PSD at T=80 K. А.M. Balagurov, I.D. Dutt, B.N. Savenko and L.A. Shuvalov, Simultaneous sweep along TOF and 2  axes. About 4000 points have been measured in parallel. TOF scale 2  scale

14 real-time Time / temperature scale: T start =94 K, T end =275 K. The heating rate is ≈1 deg/min. Diffraction patterns have been measured each 5 min. Phase VIII is transformed into high density amorphous phase hda, then into cubic phase Ic, and then into hexagonal ice Ih. Ice VIII Ic Ih Phase transformations of high pressure heavy ice VIII. Time-resolved experiment with  t=5 min. hda TOF scale Time & temperature scale

15 spn V. Lauter-Pasyuk, H. Lauter, B. Toperverg et al., Magnetic off-specular neutron scattering from (001) [Cr(12Å)/ 57 Fe(68Å)]x12 /Al 2 O 3 multilayer Intensity map of specular and off- specular scattered neutrons from the Fe/Cr multilayer (SPN data). Result of the supermatrix calculations with the model of non-collinear domains. Neutron wavelength, Å

16 prem Development and realization of new methods in time-of-flight neutron diffraction studies at pulsed and steady state nuclear reactors State Prize of the Russian Federation in 2000 FLNP, JINR Victor L. Aksenov Anatoly M. Balagurov Vladimir V. Nietz Yuri M. Ostanevich RRC KI, Moscow Victor P. Glazkov Victor A. Somenkov PNPI RAS, Gatchina Valery A. Kudryashev Vitaly A. Trounov

17 Condensed Matter Department at FLNP tit Permanent staff45 Directorate staff22 Ph.D. + students13 Doctor of science7 Candidate of science 26 Main goals:   Research at the actual fields of condensed matter science and technology.   Assistance to external users at the IBR-2 spectrometers.   Operation of spectrometers at the IBR-2 and their further development. Age distribution A new goal:   Realization of education program for young scientists.

18 IBR-2 Spectrometers at the IBR-2 reactor HRFD DN-2 TEST SKAT EPSILON NERA DN-12 FSD IZOMER (NP) YuMO DIN KDSOG REFLEX REMUR (SPN) KOLHIDA (NP) Main experimental techniques at IBR-2:   Neutron diffraction: 7   SANS: 2   Reflectometry: 2   INS: 3

19 Tem Main research topics Atomic and magnetic structure of new materials. HRFD, DN-2 Atomic and magnetic dynamics. DIN, NERA, KDSOG Non-crystalline materials, liquids, polymers, colloidal solutions. YuMO Surfaces, nanostructures of low dimension. REMUR, REFLEX Biological materials and macro-molecules. YuMO High pressure physics. DN-12, DN-2 Internal stresses in industrial materials and components. HRFD, FSD Texture and properties of rocks. SKAT, EPSILON

20 Rietv Rietveld refinement of HgBa 2 CuO 4.12 structure; IBR-2, HRFD Mercury based high-T c superconductors. Collaboration FLNP – MSU (Moscow)

21 Hg-Tc The temperature of SC phase transition at HgBa 2 Cu(O/F) 4+  as a function of oxygen / fluorine content Тhe temperature of phase transition depends on charge!

22 Hg-F-dist. Interatomic (apical) distances in HgBa 2 CuO 4 (O/F)  Apical distances depend on the amount of anions! From: A.M. Abakumov et al., PRL 80 (1998) 385.

23 cmr Colossal_Magneto_Resistivity (CMR) – effect in T 1-x D x MnO 3 manganites, T = La, Pr, D = Ca, Sr. Electrical resistivity decreases in 10 7 times under the influence of magnetic field!

24 (La 0.25 Pr 0.75 ) 0.7 Ca 0.3 MnO 3, isotope enriched: 18 O,  75%(O-18)insulating down to 4 K 16 O, 99.7%(O-16) metallic at T<100 K LPCM/Samples Giant oxygen isotope effect in (La 0.25 Pr 0.75 ) 0.7 Ca 0.3 MnO 3 (LPCM-75) N.A. Babushkina et al., Nature 391 (1998) 159

25 Temperature dependencies of lattice parameters a and c (bottom) and b (top) for the O- 16 and O-18 samples. The vertical lines mark the temperatures of CO, AFM, and FM transitions. Between T FM and room temperature the parameters of both samples are coincide. (La 0.25 Pr 0.75 ) 0.7 Ca 0.3 MnO 3, 16 O / 18 O (O-16 / O-18) 16 O / 18 O – Latt. Param. Giant oxygen isotope effect in (LPCM-75). Lattice parameters.

26 Interatomic distances and valent angles changes after oxygen isotope ( 16 O→ 18 O) exchange in LPCM O / 18 O Giant oxygen isotope effect in (LPCM-75). Structural parameters.

27 shema Diffraction experiment for measuring of internal stresses inside material or component: highly accurate, completely nondestructive, multi-phase materials, in situ mode. incident neutron beam diaphragm component (sample) detectors at By two detectors at  90  one can measure stresses in both Q 1 and Q 2 directions simultaneously. gauge volume Neutron diffraction: an effective, nondestructive technique for determining residual stresses (applied research).

28 Tar-1 Stress rig on neutron beam Tensile grip design Typical shape and size of a sample Loading device “TIRAtest”

29 adapter Residual stresses in bimetallic steel-zirconium adapter Cross-section of bimetallic adapter wall Bimetallic adapter placed at HRFD steelZr

30 Karta-1 The diffraction (111) peak width distribution for steel region. Axial deformation map for steel region. The first zirconium screw tooth: Y=0; X=5. Residual stresses in bimetallic steel-zirconium adapter

31 Tem Condensed Matter Division & IBR-2: Last 5 years Ph.D. thesis. 1. V.V. Luzin “Texture in bulk samples: experimental and model investigation” NSVR & SKAT, V.Yu. Kazimirov “New ferroelectrics – ferroelastics (CH 3 ) 2 NH 2 Al(SO 4 ) 2 6H 2 O” NERA, О.V. Sobolev “Inelastic neutron scattering by water solutions and micro-dynamics of hydration”DIN, А.N. Skomorokhov “Phonon-maxon area in excitation spectra of liquid helium” DIN, D.V. Sheptyakov “Structural peculiarities of complex copper oxides superconductors” HRFD & DN-12, D.P. Kozlenko “Structure and dynamics of ammonium halides” DN-12, 2001.

32 Tem 7. Т.А. Lychagina “Texture and elastic properties of materials: neutron diffraction studies”SKAT, S.V. Kozhevnikov “Effect of spatial splitting of polarized neutron beam: investigation and application”SPN, G.D. Bokuchva “Neutron diffraction studies of internal stresses in bulk materials” HRFD, D.Е. Burilichiev “Texture and elastic anisotropy of earth mantle rocks at high pressure”SKAT, М.V. Avdeev “The investigation of the fractal properties of global proteins surface”YuMO, V.I. Bodnarchuk “Interaction of polarized neutrons with non-collinear magnetic structures”REFLEX, А.Kh. Islamov “Structure and properties of lipid membranes: neutron diffraction studies”DN-2, YuMO, Condensed Matter Division & IBR-2: Last 5 years Ph.D. thesis.

33 User-Pr User program at the IBR-2 spectrometers Experts’ commissions Diffraction: H. Tietze-Jaensh, Germany P. Mikula, Czech Rep. V.A. Somenkov, Russia Inelastic Scatt.: P. Alexeev, Russia W. Zajak, Poland I. Padureanu, Romania Neutron optics: H. Lauter, France D.I. Nagy, Hungary A.I. Okorokov, Russia SANS: G. Pepy, France A.N. Ozerin, Russia J. Pleshtil, Czech. Rep. J. Teixeira, France Time-sharing (14 spectrometers) FLNP (35%) External regular (55%) External fast (10%) User statistics FLNP, 25% Germany, 17% Russia, 31% Poland, 5% France, 3% Others, 19%

34 Tem Conclusions Neutron scattering at the IBR-2 has the excellent present and good prospect for future because:   IBR-2 is one of the best neutron sources for condensed matter studies;   Parameters and performance of neutron spectrometers at the IBR-2 are at a world top level;   There exists a realistic program for development of spectrometers;   The staff is well experienced and there is a good balance between aged and young scientists;   There exists a good collaboration with many Institutions.

35 END

36 Tem Our problems 1. Neutron guide tubes.2. Detectors. DN-12 diffractometer: intensity gain-factor after installation of a neutron guide tube. Multi-element back-scattering detector for FSD diffractometer.

37 Tem The first steps of TOF neutron scattering for condensed matter research in FLNP (1963 – 1980)   The first TOF diffraction patterns obtained at a pulsed neutron source (Buras, Nietz, Sosnovska, 1963).   Inverted geometry for inelastic scattering (Bajorek, 1964).   Geometrical focusing in TOF diffraction (Holas, 1966).   Diffraction and inelastic scattering with pulsed magnetic field (Nietz, 1968).   Comb-like neutron moderator (Nazarov, 1972).   The first TOF structural experiment (Balagurov, 1975).   The first TOF SANS (small-angle) experiment (Ostanevich, 1975).   Correlation spectrometry at pulsed neutron source (Kroo, 1975).   The first 2D & 3D TOF diffraction patterns (Balagurov, 1977, 1980).   Axial geometry for SANS (Ostanevich, 1978).   Spin-flipper with extended working area (Korneev, 1979).

38 Tem Development of TOF technique for condensed matter research at the IBR-2 in 1981 – 2003   The first mirror polarizer for TOF spectrometer (Korneev, 1981).   Neutron guide tubes for pulsed neutron source (Nazarov, 1982).   Axial geometry for SANS (Ostanevich, 1982).   The first real-time TOF experiments with  t s  1 min. (Mironova, 1985).   Fourier-diffractometer at pulsed neutron source (Aksenov, Balagurov, Trounov, Hiismaki, 1992).   The first TOF experiments with sapphire-anvil high pressure cell (Somenkov, Savenko, 1993).   Inelastic scattering experiments at TOF reflectometer(Korneev, 1995).   Combined electronic & geometrical focusing (Kuzmin, 2001).

39 Diffr.-IBR2 The most important parameters of a pulsed source for neutron scattering experiment Resolution IntensityAverage power SpectrometerPulsed source Pulse width Experiment Duration Quality of data  What does it mean for the IBR-2 ? 

40 Diffr.-IBR2 Diffractometers at the IBR-2 1. HRFD – high resolution Fourier diffractometer crystal structure of powders 2. DN-2 – multi-purpose diffractometer single crystals, magnetic structures, real-time studies 3. DN-12 – diffractometer for microsamples high pressure experiments 4. FSD / EPSILON – stress diffractometers internal stresses in bulk samples 5. SKAT / NSVR – texture diffractometers texture of rocks and bulk samples

41 izluch Radiations for diffraction studies of internal stresses Radiation Accessibility Resolution Resolution Scanning Experiment over d over x depth geometry X-ray Synchrotron radiation Neutron With TOF neutron diffractometer (pulsed neutron source) determination of stress anisotropy is possible! up to 3 cm in steel, 6 cm in Al

42 sdvig Peak shift for E=200 GPa and loading of 20 MPa and 200 MPa Peak shift under loading for  d/d ≈ 0.001