ᐇ㦂ሗ࿌᭩ᵝᘧ䠄୍⯡฼⏝ㄢ㢟䞉ᡂᯝබ㛤฼⏝䠅㻌䠄 䈜ᮏሗ࿌᭩䛿ⱥㄒ䛷グ㏙䛧䛶䛟䛰䛥䛔䚹䛯䛰䛧䚸⏘ᴗ฼⏝ㄢ㢟䛸䛧䛶᥇ᢥ䛥䜜䛶䛔䜛᪉䛿᪥ᮏㄒ䛷グ㏙䛧䛶䛔䛯䛰䛔䛶䜒⤖ᵓ䛷䛩䚹 䠅Experimental Reportᢎㄆ᪥ Date of Approval 2017/12/4
ᢎㄆ⪅ Approver Takanori Hattori
ᥦฟ᪥ Date of Report 2017/12/2

ㄢ㢟␒ྕ Project No.

⿦⨨㈐௵⪅ Name of Instrument scientist

2017A0012

Takanori Hattoriᐇ㦂ㄢ㢟ྡ Title of experiment⿦⨨ྡ Name of Instrument/䠄BL No.䠅Neutron diffraction structure determination of hydrous silicate

BL11 PLANET

glasses under high pressure conditions: Implications for deep denseᐇ᪋᪥ Date of Experimenthydrous magma in the interior of the EarthOct 29 2017-Nov 4 2017

ᐇ㦂㈐௵⪅ྡ Name of principal investigator
Tatsuya Sakamaki
ᡤᒓ Affiliation
Tohoku Universityヨᩱ䚸ᐇ㦂᪉ἲ䚸฼⏝䛾⤖ᯝᚓ䜙䜜䛯୺䛺䝕䞊䝍䚸⪃ᐹ䚸⤖ㄽ➼䜢䚸グ㏙䛧䛶ୗ䛥䛔䚹䠄㐺ᐅ䚸ᅗ⾲ῧ௜䛾䛣䛸䠅㻌
Please report your samples, experimental method and results, discussion and conclusions. Please add figures andtables for better explanation.
㻝㻚 ヨᩱ Name of sample(s) and chemical formula, or compositions including physical form.
The sample is synthesized basaltic glass by quenching molten mixture of several oxides and carbonates. Thebasaltic composition is universal igneous rock, and glass is an analog of magma in the interior of the Earth.

㻞㻚 ᐇ㦂᪉ἲཬ䜃⤖ᯝ㻌 䠄ᐇ㦂䛜䛖䜎䛟䛔䛛䛺䛛䛳䛯ሙྜ䚸䛭䛾⌮⏤䜢グ㏙䛧䛶䛟䛰䛥䛔䚹䠅
Experimental method and results. If you failed to conduct experiment as planned, please describe reasons.
The structure of basaltic glass under pressure was determined using time-flight neutron diffraction technique.
Paris-Edingburgh press was used as a high-pressure apparatus. The neutron diffraction experiments wereperformed at different pressure conditions (P: 1 atm ~ 18.0 GPa). Figure 1 shows the structure factor, S(Q), ofbasaltic glass. In order to understand the structural evolution of the glass, we focused on a change in the first
sharp diffraction peak (FSDP) in S(Q) with pressure. Since the FSDP reflects the intermediate-range order (IRO)of silicate network, the pressure dependence of the FSDP is a good indicator of pressure-induced structuralchanges of the glass. Enlarged S(Q) is shown in Figure 2. This clearly demonstrates the shift of the FSDP tohigher-Q with pressure, which indicates the shrinkage of IRO structure with increasing pressure. This figure also
exhibits that second peak on the right of the FSDP changes drastically with pressure. The peak is called thesecond sharp diffraction peak, SSDP, and reflects shorter-range ordering.

Figure 1
Structure factor, S(Q), of basaltic glass atdifferent pressure.

Figure 2
Pressure-induced change of the FSDP and the SSDP.

㻞㻚 ᐇ㦂᪉ἲཬ䜃⤖ᯝ䠄䛴䛵䛝䠅㻌 Experimental method and results (continued)
Radial distribution function, G(r), which is obtainedby Fourier transformation of S(Q), provides us an
information about glass structure of real space. Figure 3
exhibits the G(r) at different experimental conditions.
The peak around 1.6 ǖ indicates the bond length
between tetrahedral cation (T) and oxygen (O), and thelength is less sensitive to pressure. On the other hand,
O-O bond length is shown around 2.6 ǖ and the bondlength became shorter with pressure.
We can find clear difference between neutron andX-ray diffraction of basaltic glass. Figure 4 and Figure 5
indicate the comparison of S(Q) and G(r) between
neutron (red) and X-ray (black) diffraction, respectively.
In the case of neutron diffraction, scattering intensityfrom oxygen is larger than X-ray. Therefore, results ofFigure 3Radial distribution function, G(r) of basaltic glass
at different pressure.

neutron diffraction enable us to better understand the change in TO4 tetrahedra under pressure. Combining bothneutron and X-ray diffraction, we can reveal the magma behavior at the depth of the Earth.

Figure 4
Comparison of S(Q) between neutron and X-ray
diffraction.

Figure 5Comparison of G(r) between neutron and X-ray
diffraction.