実験報告書様式（一般利用課題・成果公開利用）（ ※本報告書は英語で記述してください。ただし、産業利用課題として採択されている方は日本語で記述していただいても結構です。 ）MLF Experimental Report

提出日 Date of Report
2017/07/02

課題番号 Project No.

装置責任者 Name of responsible person

2015A0099

Kenichi Oikawa

実験課題名 Title of experiment

装置名 Name of Instrument/（BL No.）

Development of high resolution quantitative resonance absorption

BL10and Bragg edge imaging for engineering and

実施日 Date of Experiment

metallurgic applications and optimization of single crystal growth

2016/04/16

実験責任者名 Name of principal investigator

09：00

Anton Tremsin

2017/01/18

所属 Affiliation9:00

21:00 ～

2016/04/22

21:00 ～

2017/01/21

University of California at Berkeley, USA
試料、実験方法、利用の結果得られた主なデータ、考察、結論等を、記述して下さい。（適宜、図表添付のこと）
Please report your samples, experimental method and results, discussion and conclusions. Please add figures andtables for better explanation.
1. 試料 Name of sample(s) and chemical formula, or compositions including physical form.
1.

BaBrCl:Eu gamma scintillator sealed in quartz ampule, 12 mm internal diameter, ~6 cm tall

2.

CssLiLaBr6:Ce gamma scintillator sealed in quartz ampule, 12 mm internal diameter, ~6 cm tall

3.

Aluminium welds, ~10 cm x 1 cmx5 cm

4.

Steel welds, ~2x2x2 cm^3, different filler speed

5.

TlBr gamma semiconductor detector material, ~5x5x5 mm^3, 4 pieces

6.

NaI gamma scintillator material, ~11 mm internal diameter, ~5 cm tall, sealed in quartz tube

7.

CsI gamma scintillator, ~2 cm disk, 10 mm thick

2. 実験方法及び結果 （実験がうまくいかなかった場合、その理由を記述してください。）
Experimental method and results.

If you failed to conduct experiment as planned, please describe reasons.

All the samples were measured as planned: the gamma scintillator and semiconductor materials weremeasured while melted in specially designed and manufactured vacuum furnace installed in neutron beam. The
furnace was controlled with a feedback loop for accurate temperature to be maintained in the sample. The
sample materials were melted (BBC at 850C and CLLB at 550C) and then slowly grown into single crystal
materials for the studies of growth conditions, which can be optimized with the in-situ diagnostics attemptedin the present experiments. The results of these measurements on the scintillators are very interesting andare met with great interest by the crystal growth community and are being prepared for the publication in arefereed journal, most likely J. of Crystal Growth and Design.
Neutrons for a broad range of energies (including both thermal and epthermal energies) were registered ineach experiment providing the opportunity to study simultaneously the elemental composition of the materials
and their crystallographic properties and interface location between the liquid and solid phases. Neutron
resonance absorption was used to evaluate the elemental composition of CLLB sample. Concentration of Li isshown in Fig. 1.left, which was reconstructed from the measured spectra while sample was melted to the white1dashed line. The integration time of this image was ~40 minutes, acceptable for the crystal growth
processes, although a higher beam intensity will definitely be very useful for quantification of otherelements, which is not possible with current neutron statistics acquired in our experiment.
The challenge of energy-resolved imaging with the TOF technique lies in the requirement to detectboth position and time for every registered neutron with fluxes exceeding now 107 n/cm2/s. Such highfluxes are necessary for high-resolution imaging studies, where multiple transmission spectra aremeasured within areas as small as 55x55 µm2, with as many as >250000 spectra measured at thesame time. Analysis of this data allows reconstruction of the entire map of some microstructure
parameters with spatial resolution of ~100 µm, all from one measurement. The deficiency oftransmission imaging should be pointed out here: only the integral characteristics through the sample
thickness are obtained by this technique. However, in some cases that averaged information issufficient, as demonstrated by the studies of weld cross sections and other samples.
0.6
Al weld area
Al rolled plate
SteelTransmission

0.5

3310.4

311
222

200
220

0.3
0.2
211

0.12001100123111456

Wavelength (A)Fig. 1. (Left) Li concentration in Cs2LiLaBr6:Ce sample, measured through energy resolved transmission spectroscopy.
(Center) Neutron transmission spectra measured at BL10 for various polycrystalline metal samples, Fig. 1.a (~1 cm steel, ~10cm Al and ~0.5 cm nickel) as well as single-crystal Ni alloy. (Right) The map of the residual strain reconstructed from (110)
Bragg edge measured within each pixel of our dataset. An accurate fitting of a 5-parameter analytic function allows
reconstruction of residual strain with sub-mm spatial resolution, across the entire sample measured in one experiment. The
color legend represents the strain values measured in microstrain

The microstructure within relatively thick metal samples was also studied in our experiments throughBragg edges. Typical spectra, measured for steel and Al samples, are shown in Fig. 1. A large
difference in the measured spectra of the Al weld sample is observed for the areas within the weld
(where friction stir welding produced material with small grains free of strong texture) and within theadjacent rolled plate area, exhibiting a strong texture variation through the sample thickness. Suchtransmission spectra are obtained in each pixel of our detector in one measurement. The residualstrain within a steel weld sample, reconstructed from the measured transmission, is shown in Fig. 1,
reveals some microstructure variations formed within the weld area. The location of the filler material
is excluded from that image since the filler material was from other metal composition and had
different lattice parameter. It demonstrates how the energy resolved imaging helps to visualize thebulk variation of microstructure within the welds and other samples, which can be complementary to
many other well established characterization techniques.

2