• Highly-sensitive NMR technique has been developed by manipulation polarization of nuclear spins via control of transport characteristics in GaAs and InSb quantum structures. This highly-sensitive NMR can be applied to two-dimensional and nanostructures. Furthermore, ideal gate controllability has been demonstrated in InSb quantum structures with Al2 O3 dielectrics. More importantly, the concept of generalized coherence time was introduced, where noise characteristics felt by nuclear spins can be measured including their frequency dependence. This concept will bring about a change in all nuclear-spin related measurements.

Next generation InSb devices based on good gate controllability. Various nuclear-spin based measurements and NMR utilizing the concept of generalized coherence time. Highly-sensitive NMR is now important for fundamental physics studies. In the future, it will contribute to quantum information processing.

We have developed a technique for quantitative analysis of microstructures (e.g., dislocations and irradiation defect aggregates) of activated and nuclear-burned specimens in the context of the Week Beam Scanning Transmission Electron Microscope (WB-STEM) method, which boasts extremely high measurement accuracy as a quantitative analysis method for lattice defects.
In combination with a dedicated heated sample holder with fully automated temperature measurement and current control in a cartridge-type heating furnace, changes in dislocation microstructure can be dynamically measured in-situ along with a highly reliable temperature history.

Conventional TEM methods require expertise in reciprocal space and dislocation theory, but our WB-STEM method is equipped with automatic analysis software for film thickness measurement and dislocation loop feature extraction, making it possible to analyze irradiation defects easily and precisely.

• Since its design, the WB-STEM method has been developed for implementation and on-site repair in radiation controlled areas where nuclear materials are handled, with special aperture and diffraction disc selection equipment, control and analysis software.
• WB-STEM accepts irradiation defect analysis of activated specimens from all over the world, including RPV monitoring specimens from European reactors and neutron-irradiated materials from US research reactors.
• It is also used to analyze the properties of iron-containing nuclear fuel simulated debris in decommissioning projects.

We support research organizations that currently use transmission electron microscopy to observe microstructures to introduce the WB-STEM method by special modification. We will instruct researchers who have no experience using transmission electron microscopy in the procedure for dislocation analysis.

• The emergence of stress corrosion cracking is one of the most important issues from the viewpoint of aging management and maintenance of nuclear power plants. There is a large discrepancy between stress corrosion cracking and other cracks such as fatigue cracks from the viewpoint of nondestructive testing and evaluations, which requires suitable specimens containing stress corrosion cracking for the development of nondestructive testing and evaluation techniques and also for personnel training. However, artificially introducing stress corrosion cracking needs large cost and long time. Furthermore, several studies have pointed out that such articial stress corrosion cracking is not always similar to natural ones. On the basis of the background above, we develop a method to fabricate "imitative" stress corrosion cracking specimens using diffusion bonding.

The method enables one to introduce a region whose response is almost identical to actual stress corrosion cracking from the viewpoint of nondestructive testing. Whereas the dimension of the region is accurately controllable, the method requires much less cost and time comparing the conventional ones using corrosive environment. Patent is already applied for.