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Ex Expe perime rimenta ntal l da data a che heck k of SAN ANS me meas asur uremen ement Akhona Gura 1 , Puseletso Mokoena 2 , Modiehi Tshabalala 2 , Nangamso Nyangiwe 3,5 , Nametso Mongwaketsi 4,5 1.Walter Sisulu University,

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SLIDE 1

Ex Expe perime rimenta ntal l da data a che heck k of SAN ANS me meas asur uremen ement

Joint Institute for Nuclear Research, Frank Laboratory of Neutron Physics

Akhona Gura1, Puseletso Mokoena2, Modiehi Tshabalala2, Nangamso Nyangiwe3,5, Nametso Mongwaketsi4,5

1.Walter Sisulu University, Chemistry Dept. Private Bag X1 Mthatha, 5117

  • 2. University of Free State, Physics Dept, P.O Box 339, Bloemfontein, 9300
  • 3. University of the Western Cape, Physics Dept, Bellville,
  • 4. Stellenbosch University, Chemistry & Polymer Science Dept, Private Bag X1, Matieland, 7602
  • 5. iThemba LABS, Materials Research Dept, P.O Box 722, Somerset West, 7129

Supervisor: Dr. A. Kuklin Co-supervisor: R.V. Erhan, PhD

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SLIDE 2
  • Introduction (SANS)
  • Properties of neutrons
  • SANS Techniques & Applications
  • Principles of SANS
  • SANS Sources
  • IBR-2 Reactor
  • SANS equipment at JINR
  • Project Aim
  • Data Analysis and Results
  • Conclusion
  • References
  • Acknowledgements

Ou Outline ne

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SLIDE 3

Sm Small Angle e Neutron

  • n Sc

Scattering ng (SA SANS) S)

 Neutrons scattering is technique whereby a neutron beam is directed to a sample and neutrons are scattered at an angle theta with respect to the incident beam.  The scattered neutrons collected in the detector give the information about the properties of the studied material.  Scattering pattern is analyzed to give information about the size, shape, degree of polydispersity and phase transition.  Sample studied using SANS may be in length scale of 10 to 1000 Å.  The angles of scattering are in the range of ~ 0.2–5°.

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SLIDE 4

Propert perties ies of f neutrons ns

  • The neutron was discovered by Chadwick in 1932.
  • It has zero charge and a mass of 1.0087 atomic mass unit.
  • It has a half life of 894 seconds.
  • The neutron usually penetrates well through matter and is useful for

investigating bulk condensed matter.

  • It has a spin of 1/2 and a magnetic moment of -1.9132 nuclear magnetons.
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SLIDE 5

Types es of f neutrons ns

  • Thermal neutrons (> 0.025 eV)
  • Fast neutrons (> 1 eV)
  • Slow neutrons (> 0.4 eV)
  • Epithermal neutrons (> 0.2 eV)
  • Cold neutrons ( 5x 10 -5 to 0.025 eV)
  • Continuum region neutrons (0.01 MeV to 25 MeV), etc
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SLIDE 6

Techni hniques ques & A Appl plica ications ions

 Neutro tron techniq niques ues

  • SANS
  • Reflectrometry
  • Neutron activation analysis
  • Neutron diffraction
  • Neutron radiography
  • Neutron backscattering

 SANS applicati ations ns

  • Chemistry – Structure and interactions in colloidal solutions

– Mechanisms of molecular self-assembly in solutions, etc

  • Materials Engineering – Investigations of crystalline structure

– Investigations of ferrofluids, etc

  • Polymers – Structure of micro phase for separated block polymers, etc
  • Biology – Organization of biomolecular complexes in solutions

– Mechanisms and pathways for protein folding, etc

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SLIDE 7

Princ ncip iples les of SA SANS

where

  • Q – wave vector
  • θ – scattering angle
  • λ – wavelength of incident beam

The scattering intensity is defined as: where

  • I(Q) – scattering intensity
  • Ф – density of particles in volume
  • F(Q) – form factor
  • S(Q) – structure factor

I(Q)= ɸF(Q)S(Q)

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SLIDE 8

Neutron

  • n So

Sources es

 Spallat lation n neutro ron n source ces Most powerful source – ISIS facility in the United Kingdom  Nucle lear ar reacto tors rs (Continuous & Pulsed) Nuclear fission Most powerful source – High Flux Reactor at Institute Max von Laue-Paul Langevin in France  There are 37 neutron sources in 21 countries ( Europe 23, North America 10, Japan 2, Australia 1, India 1)  JINR supervises the activity of the IBR-2 pulsed reacto tor (FLNP) P)

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SLIDE 9

IBR BR-2 2 Reactor

  • r

 IBR-2 reactor produce intense pulse neutron flux at the moderator surface ~1016 n/cm2/s, with a power

  • f 1850 MW in pulse

IBR-2 Spectromet meters: rs: Small angle scattering: YuMO Diffraction: HRFD, DN-2, DN-6 (project), SKAT- EPSILON, FSD, DN-12 Reflectometry: REMUR, REFLEX, GRAINS Inelastic scattering: DIN-2PI, NERA-PR  Nuclear Physics: ISOMER, KOLHIDA Neutron Activation Analysis: REGATA  Irradiation Facility

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SLIDE 10

SA SANS S equipm pment ent at F FLNP (J (JINR)

1 – reflectors, 2 – reactor zone with water modulator, 3 – chopper, 4 – first collimator, 5 – neutron guide 6 – second collimator, 7 – Thermostat, 8 – sample table, 10 – Vanadium standard, 11,12 – scattering detectors, 14 – detector (direct beam)

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SLIDE 11

Aim

  • Data Analysis (Fitter, SASFit and Origin software packages)
  • Interpretation of data
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SLIDE 12

Apoferrit

  • ferritin

in

Ferritin is a ubiquitous intracellular protein that stores iron and releases it in a controlled fashion. The amount of ferritin stored reflects the amount of iron stored. The protein is produced by almost all living organisms, including algae, bacteria, higher plants, and animals. In humans, it acts as a buffer against iron deficiency and iron overload.* Ferritin is a globular protein complex consisting of 24 protein subunits and is the primary intracellular iron-storage protein in both prokaryotes and eukaryotes, keeping iron in a soluble and non-toxic

  • form. Ferritin that is not combined with iron is

called apoferritin. It consists of 24 four-helix bundles and is able to self assemble into 12 nm spherical protein with a 8 nm diameter cavity. *Iron Use and Storage in the Body: Ferritin and Molecular Representations, Rachel Casiday and Regina Frey, Department of Chemistry, Washington University, St. Louis.

Figure 1 Structure of the murine ferritin complex Granier T, Langlois d'Estaintot B, Gallois B, Chevalier JM, Précigoux G, Santambrogio P, Arosio P (January 2003). "Structural description of the active sites of mouse L-chain ferritin at 1.2 A resolution". J. Biol. Inorg. Chem. 8 (1–2): 105–11.

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SLIDE 13

Da Data ta Analysis ysis & R Result ults

Intensity (cm-1) Q (A-1)

Poro rod d Plot Guinier nier Plot

  • B. Hammouda, "Structure Factor for Starburst Dendrimers”, J. Polym. Sci., Polym. Phys.

Ed., 30, 1387-1390 (1992)

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SLIDE 14

Test st Da Data

Data parameters Rg = 198.998 ± 14.733 Chisq = 1.359 I(Q) = 4439.9 ± 146.099

Plot of test data

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SLIDE 15

Da Data Analysis ysis of f SA SANS S measurem ement ent

Data parameters Rg = 47.4389 ± 18.492 Chisq = 2.3486 I(Q) = 1.38799 ± 0.417

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SLIDE 16

Da Data Analysis sis using SA SASF SFit it soft ftwa ware re

SASFit plot of Apoferittin data Porod plot Guinier plot Plot of Apoferittin data

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SLIDE 17

Da Data Analysis ysis using Fitter soft ftwa ware

Fitter plot of Apoferittin data Fitted Fitter plot of Apoferittin data Guinier plot of Apoferittin data Porod plot of Apofirattin data

LogI(Q)/nm Log (Q2)/A-2 Log (Q2)/A-2

LogI gI(Q)/ Q)/nm

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SLIDE 18

Test data treatment detector image Detector distance = (A) 18 m and (B) 15 m

2D D detector

  • r images

A B

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SLIDE 19

2D D detector

  • r images

Apoferittin data treatment detector image Detector distance : (A) 18 m and (B) 15 m A B

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SLIDE 20

Conc nclus lusion ion

  • Data analyzed successfully using Origin, SASFit and Fitter
  • It was shown how such a shape of the graph can determine the

shape of the molecule.

  • Results showed that Apoferritin is a good molecule for calibration
  • f SANS experiments for spherical objects
  • Softwares exist with good mathematical backgrounds for the

reconstruction of the shape of a molecule using data collected from SANS experiments

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SLIDE 21

Refer ferenc ences es

  • King S.M., Small angle neutron scattering, ISIS Facility 1995
  • Ghosh R. E, Egelhaaf S.U and Rennie A R., A computing guide for small angle scattering

experiments, Institut Max von Laue, Paul Langevin, 2012

  • JINR www.jinr.ru
  • Institute Laue-Langevin, France www.ill.fr
  • Software package SASfit for fitting small-angle scattering curves, Laboratory for Neutron

Scattering, Paul Scherrer Institut, PSI, Switzerland

  • A.G.Soloviev, A.V.Stadnik, A.H.Islamov and A.I.Kuklin, ``Fitter. The package for fitting a

chosen theoretical multi-parameter function through a set of data points. Application to experimental data of the YuMO spectrometer. Version 2.1.0. Long Write-Up and User's Guide''. Communication of JINR E10-2008-2, Dubna, 2008.

  • Wikipedia www.wiki.com
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SLIDE 22

Ackn knowl

  • wledgem

edgements ents

  • Summer Practice Organizing Committee
  • National Research Foundation (NRF)
  • Department of Science & Technology (DST), South Africa
  • FLNP
  • YuMO team
  • Dr. Aleksandr Kuklin
  • Raul Victor Erhan, PhD
  • Supervisors from our various institutions