DEVELOPMENT OF HIGH RESOLUTION TRANSMISSION METHODYoshiaki Kiyanagi*, Fujio Hiraga, Takashi Kamiyama, Akira Homma, Fumiyuki Fujita and Michihiro Furusaka Division of Quantum Science and Engineering, Graduate School of Engineering, Hokkaido University, Kita-13, Nishi-8, Kita-ku, Sapporo 060-8628, Japan *Contact person, Fax. +81-11-706-7368, E-mail: kiyanagi@qe.eng.hokudai.ac.jp

Short summary of work performed in our universityResidual strain measurement and mapping of residual strain by Bragg edge transmissionMapping of structure change around welded position (Under progress)

Principal of Bragg edge transmissionModerator2d detectorNeutron beamDirect and transmitted beam is observedCharacteristic structure of Bragg edge will appear depending on the crystal structure and the texture.Bragg edge

Energy Dependent Images Vinyl sheet 0.5mmPolyethylene 5mmCd cover

Energy dependent images from 0.001 to 70 eV0.03~0.08 eV0.2~0.7 eV0.7~70 eV0.001~0.003 eV0.007~0.02 eV

Material identification by using difference of cross sectionss from BNL325ABC

Experimental setup for strain measurementsSiteSirius beam line at KENSDetectorLi-glass scintillatorExperimental setup

Detector and sample2d detector of Li-glass scintillatorsExpanded photo around loadPosition of bendingBending load

Principal of strain measurements Strain is defined as hkl = (d1hkl d0hkl) / d0hkl 100

Bragg edge is fitted by using a theoretical formula to define the Bragg edge positionFitting resultExperimental data

Cross section at different row of the detector

Strain of each plane

Two dimensional distribution of the strainxyyExpanded photo of the sample Pixel number of the detectorxxxyyStrain (%)Strain (%)

Change of micro cross section around (110) planex12345678(Row number)Micro cross section (barns)Micro cross section (barns)Neutron wavelength(A)

Summary for strain measurementsStrain was observed around the region where large load was expected.

Cross section varied around Bragg edges. The reason should be explained.

Inspection of the structure and texture around welded position by using neutron total cross sectionFe1Fe2WeldedHeat affected zone(HAZ)3.4mm5.1mm6.8mm(Under progress at Hokkaido linac facility)

Micro structures appeared around Bragg edges of SS304

Change of effective total cross section of Si depending on the particle size(Under progress)

Simulation of transmission of Be at different distance from sample to detector to study the effect of multiple scatteringThere is almost no difference. There are no signals around direct beam. Is there problem in the kernel in forward direction?

Summary(Effective) Total cross section is very strange, varying depending on the sample condition.Experimental results are useful to consider or deduce the information included in the transmission cross section data.It is necessary to perform the simulation calculation taking into account the crystal or texture structures in the sample.It may not be easy to explain the total cross section data since it may include small angle scattering and so on.

Tentative Work Plan1st Year(1) Model experiments to get the effect of the crystal structure(2) Texture observation of steel welding material by Bragg edge transmission (3) Simulation calculations to study the effect of the beam divergence and multiple scattering on the imaging and the Bragg edge

Work plan 22nd Year(1) Data analysis and the explanation of the experimental data obtained last year(2) Designing of the code system for processing the imaging data

3rd YearContinuation of development of the data analysis(2) Experiments on practical materials

25mm0.5mm5mmA30mmt