Development of a non-destructive depth-selective quantification method for sub-percent carbon contents in steel using negative muon lifetime analysis

鋼鉄の品質管理・日本刀など文化財の非破壊分析も 鋼鉄中のわずかな炭素を素粒子で透視する --ミュオンによる新しい非破壊微量軽元素分析法の開発--. 京都大学プレスリリース. 2024-02-09.The amount of C in steel, which is critical in determining its properties, is strongly influenced by steel production technology. We propose a novel method of quantifying the bulk C content in steel non-destructively using muons. This revolutionary method may be used not only in the quality control of steel in production, but also in analyzing precious steel archaeological artifacts. A negatively charged muon forms an atomic system owing to its negative charge, and is finally absorbed into the nucleus or decays to an electron. The lifetimes of muons differ significantly, depending on whether they are trapped by Fe or C atoms, and identifying the elemental content at the muon stoppage position is possible via muon lifetime measurements. The relationship between the muon capture probabilities of C/Fe and the elemental content of C exhibits a good linearity, and the C content in the steel may be quantitatively determined via muon lifetime measurements. Furthermore, by controlling the incident energies of the muons, they may be stopped in each layer of a stacked sample consisting of three types of steel plates with thicknesses of 0.5 mm, and we successfully determined the C contents in the range 0.20–1.03 wt% depth-selectively, without sample destruction

Development of a non-destructive depth-selective quantification method for sub-percent carbon contents in steel using negative muon lifetime analysis

Ninomiya K., Kubo M.K., Inagaki M., et al. Development of a non-destructive depth-selective quantification method for sub-percent carbon contents in steel using negative muon lifetime analysis. Scientific Reports 14, 1797 (2024); https://doi.org/10.1038/s41598-024-52255-5.The amount of C in steel, which is critical in determining its properties, is strongly influenced by steel production technology. We propose a novel method of quantifying the bulk C content in steel non-destructively using muons. This revolutionary method may be used not only in the quality control of steel in production, but also in analyzing precious steel archaeological artifacts. A negatively charged muon forms an atomic system owing to its negative charge, and is finally absorbed into the nucleus or decays to an electron. The lifetimes of muons differ significantly, depending on whether they are trapped by Fe or C atoms, and identifying the elemental content at the muon stoppage position is possible via muon lifetime measurements. The relationship between the muon capture probabilities of C/Fe and the elemental content of C exhibits a good linearity, and the C content in the steel may be quantitatively determined via muon lifetime measurements. Furthermore, by controlling the incident energies of the muons, they may be stopped in each layer of a stacked sample consisting of three types of steel plates with thicknesses of 0.5 mm, and we successfully determined the C contents in the range 0.20–1.03 wt% depth-selectively, without sample destruction

Materials and Life Science Experimental Facility at the Japan Proton Accelerator Research Complex IV: The Muon Facility

A muon experimental facility, known as the Muon Science Establishment (MUSE), is one of the user facilities at the Japan Proton Accelerator Research Complex, along with those for neutrons, hadrons, and neutrinos. The MUSE facility is integrated into the Materials and Life Science Facility building in which a high-energy proton beam that is shared with a neutron experiment facility delivers a variety of muon beams for research covering diverse scientific fields. In this review, we present the current status of MUSE, which is still in the process of being developed into its fully fledged form

Feasibility Study for NITE SiC/SiC as the Target Material for Pions/Muons Production at High-Power Proton Accelerator Facilities

The feasibility study for Nano-Infiltration and Transient Eutectic phase process SiC/SiC (NITE SiC/SiC)NITE SiC/SiC as a potential novel target material for pions/muons production at high-power proton accelerators facilities is in progress. Compared with graphite that is the principal target material for pions/muons production, higher transport efficiency and higher oxidation resistance can be expected. However, the residual radiation dose of NITE SiC/SiC is 400 times higher than that of graphite a year after the irradiation. To validate the simulation, the residual radionuclides of the irradiated samples have been analyzed by gamma-ray spectroscopy. To understand the thermal shock behavior, NITE-SiC/SiC was included in the HRMT35 experiment at CERN’s HiRadMat facility. In these studies, NITE SiC/SiC is proved to be a promising material for pions/muons production with the higher transport efficiency and the oxidation resistance, though the maintenance scenario has to be carefully designed due to higher residual radiation dose. The thermal shock resistance and proton-irradiation resistance of NITE SiC/SiC will be confirmed to be applied for the pions/muons production

Fabrication and Low-Power Test of Disk-and-Washer Cavity for Muon Acceleration

The muon g-2/EDM experiment is under preparation at Japan Proton Accelerator Research Complex (J-PARC), and the muon linear accelerator for the experiment is being developed. A Disk-and-Washer (DAW) cavity will be used for the medium-velocity part of the accelerator, and muons will be accelerated from v/c=ß=0.3 to 0.7 with the operating frequency of 1.296 GHz. Machining, brazing, and low-power measurements of a prototype cell reflecting the design of the first tank of DAW were performed to identify fabrication problems. Several problems were identified, such as displacement of washers during brazing, and some measures will be taken in the actual tank fabrication. In this paper, the results of the prototype cell fabrication will be reported