Su6600

We examined surface features of 10 regolith particles (average diameters = 68–241 μm) including iron sulfide (Supplementary Table. 1) using a field emission SEM (FE-SEM; Hitachi SU6600) at the ESCuC after the initial routine description. The particles were placed on an Au-coated holder for SEM observations, without a conductive coating, using an electrostatically controlled micromanipulation system. Until these SEM observation, the Itokawa particles had never been exposed to an atmospheric environment, thus minimizing the contamination and alteration of the studied particles^{66 (link)}. We performed secondary electron (SE) imaging at accelerating voltages of 1.5 and/or 2.0 kV under high vacuum with an electron beam current of ~10 pA.
Three Itokawa particles (RA-QD02-0286, RA-QD02-0292, and RA-QD02-0325) were transferred onto an adhesive carbon-conductive tape for further analysis. We determined the elemental compositions of their surfaces with an energy-dispersive X-ray spectrometer (EDX) using an FE-SEM (Hitachi SU6600) equipped with a X-Max^N 150 mm² (Oxford Instruments) in JAXA and an FE-SEM (Hitachi SU6600) equipped with a Bruker XFlash^® FlatQUAD detector at the Institute for Molecular Science (IMS, Higashi-Okazaki, Japan). The accelerating voltage for SE imaging was 1.5 kV, whereas for EDS analysis we used 5 and 10 kV.

Following the last determination of the flow rate, three characteristic specimens were selected from each group of discs. After being passed through ascending grades of alcohol, the discs were immersed in hexamethyldisilazane for 10 minutes and then left on filter paper at room temperature for 1 day. Dentin discs were fractured using a dental chisel perpendicular through the surface, coated with Au, and inspected at a 15 kV acceleration voltage on the treated and fractured surfaces (SU-6600, Hitachi High-Technologies Corporation, Tokyo, Japan).