• We develop technology of the cyclotron accelerator and its application as follows. 1)Ion source (particularly heavy ion source), 2)design of ion optics, 3)device control system for the cyclotron, 4)RF system, 5)detectors for charged particles, gamma ray, and neutron, 6) radiation test by ion and neutron beam.

We have beam lines dedicated to the neutron irradiation and the ion irradiation, respectively. We can provide fast neutron beam (20-70 MeV), and various ion beam such as p, alpha, and heavy ions up to Xe. We also develop a neutron imaging technique using fast neutron.

• In contrast to other scattering techniques, such as x-ray and electron diffractions, neutron scattering has the following advantages: 1) light atoms, such as H and Li, can be detected; 2) electron spins can be detected; 3) low energy excitations can be investigated. Using the neutron scattering technique, we search for macroscopic quantum phenomena in many-body electron systems, such as macroscopic singlet ground states in the quantum frustrated magnets and spin-fluctuation-mediated unconventional superconductors.

As noted above, neutron scattering can be used for investigating magnetic structure, spin dynamics, light atom positions in crystalline materials and their dynamics. Hence, this technique is very useful when those pieces of information are to be known.

• Microwave processing is one of the attractive fields in recent materials processing. We perform various materials processing using non-equilibrium reaction field induced by microwave and/or ultrasonic irradiation. The topic contains powder metallurgy, nitride coatings, synthesis of new functional materials, fabrication of nanoparticles, etc. Recently we have developed a new TiN coating method using our microwave irradiation equipment operated at a frequency of 2.45 GHz. The method is simple but applicable to various substrates with complex shape. This method can be applied to various nitride coatings and will open a new coating technology in many fields of applications.

The major targets of TiN coatings are for cutting tools, ball bearings, dental implants, die and mold for stamping, and ornaments. The newly developed method makes it possible to perform nitride coatings within a short time using a standard microwave heating equipment. We hope to conduct collaborative research with a willing company for a practical application of these technology.

Nitride semiconductor free-standing substrate production method
https://www.t-technoarch.co.jp/data/anken_en/T14-121.pdf
This invention relates to a technique for producing high-quality nitride semiconductor freestanding substrates at a lower cost. The invention also includes the use of SCAlMgO4 substrates as seed crystals. The dislocation density of nitride semiconductors on this substrate becomes lower. By controlling the crystal polarity, the crystal diameter can be expanded as well as the thickness of the nitride semiconductor.

It is possible to fabricate freestanding nitride semiconductor substrates with lower through-dislocation density than conventional substrates. Furthermore, the cleavage property of ScMgAlO4, which serves as the substrate, facilitates the exfoliation of the nitride semiconductor and reduces the cost of substrate fabrication.

• Usage of ScAlMgO4 as a source substrate.
• Expansion of crystal diameter by using N-polar growth
• When ScAlMgO4 is used as the seed crystal and AlN is formed as the surface protective layer of this crystal, the surface shall be further nitrided after oxidation of the surface.
• The main surface of the seed crystal shall be inclined 0.4 to 1.2° from the c-plane.

This invention is to provide high-quality, low-cost free-standing nitride semiconductor substrates for optical devices such as light-emitting diodes and lasers, and transistors operated under high power, high voltage, and high frequency. Companies are expected to verify the commercialization of the product.

• 1. Development of Distributed Feedback (DFB) Laser Diodes (LD) widely used in optical communications systems realizing a highly information-based society. This LD increases the transmission capacity by 25,000 times per fiber which means the bit rate of 10Tb/s.
• 2. Nitride semiconductors famous for blue light emitting diodes.
• (a) Proposal of InGaAlN system considering device applications in 1989
• (b) Success in growth of single crystalline InGaN by metalorganic vapor phase epitaxy (MOVPE) in 1989
• (c) Prediction of band-gap energy (Eg) of InN much smaller than the values reported in 1980s and its 　 experimental confirmation in 2002
• (d) Observation of photoluminescence from InGaN in 1991
• (e) Prediction of phase separation in InGaAlN in 1997

DFB-LD: Fabrication of periodic structure with submicron scale, Epitaxial growth of semiconductor films on the substrate with fine structures, LD fabrication process, device evaluation, and device simulation

Nitride Semiconductors: MOVPE growth, N-polar growth, Evaluation of semiconductor materials, Fabrication of light-emitting devices, solar cells, and high-power transistors

• Conventional X-ray imaging methods that rely on X-ray attenuation cannot generate clear contrast in the observation of low-density materials such as polymers consisting of low-Z elements. However, the sensitivity to the materials can be improved drastically by X-ray phase imaging that detects X-ray refraction caused by the materials. X-ray Talbot or Talbot-Lau interferometry consisting of X-ray transmission gratings is now constructed in laboratories for X-ray phase imaging. X-ray phase tomography is also realized, enabling high-sensitive three-dimensional observation.
• X-ray phase imaging can be utilized for X-ray non-destructive testing of industrial products and baggage that cannot be checked conventionally.

We aim at appending a phase-contrast mode to micro-CT apparatuses and developing screening apparatuses in production lines.

• We have been developing methods for explicating the dominant factors that determine the physical and chemical properties of materials and stacked structures used in human societies. Since the number of element atoms which consists of advanced materials has been increasing, and the crystallographic structure of the materials has become very complicated, both the various properties and reliability of the materials fluctuate significantly in nano-scale, and thus, deteriorate easily due to the local damages of the materials.

To design the optimal structure, composition of materials, and the fabrication process of both materials and stacked structures, we are going to develop a method of analyzing the atomic structure of thin film materials based on quantum mechanics and experimental methods for measuring material properties, atomic scale damage or defects in nano-materials.

• 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.