Measurement of displacement cross section of structural materials utilized in the proton accelerator facilities with the kinematic energy above 400 MeV

Shin-Ichiro Meigo,Hiroki Matsuda,Hiroki Iwamoto,Makoto Yoshida,Tatsushi Nakamoto,Fujio Maekawa,Taku Ishida,Yosuke Iwamoto,Shunsuke Makimura,Shoichi Hasegawa,Z Ge,W Wang,Y Chen,N Shu,H Zhang

doi:10.1051/epjconf/202023906006

Shin-Ichiro Meigo, Hiroki Matsuda + Show 13 more

Open Access

https://doi.org/10.1051/epjconf/202023906006

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Abstract

For damage estimation of structural material in the accelerator facility, displacement per atom (DPA) is widely employed as an index of the damage calculated based on the displacement cross section obtained with the calculation model. Although the DPA is employed as the standard, the experimental data of displacement cross section are scarce for a proton in the energy region above 20 MeV. Among the calculation models, the difference exists about 8 times so that experimental data of the displacement cross section is crucial to validate the model. To obtain the displacement cross section, we conducted the experiment in J-PARC. As a preliminary result, the displacement cross section of copper was successfully obtained for 3-GeV proton. The present results showed that the widely utilized the Norgertt-Robinson-Torrens (NRT) model overestimates the cross section as suggested by the previous experiment for protons with lower energy.

Highlights

To decrease hazard of the radioactive waste produced in a nuclear reactor, Japan Atomic Energy Agency (JAEA) proposes the Accelerator Driven System (ADS) with extremely high power accelerator such as 30 MW with proton kinetic energy of 1.5 GeV
I Ed where E is the kinetic energy of projectile, dσ/dTi is recoil atom kinetic energy distribution, Ti is the kinetic energy of recoil particle i valid to maximum of Timax, Ed is the effective threshold displacement energy, and ν(Ti) is the number of defects (Frenkel pairs) showing the defect production efficiency defining by a vacancy and a self-interstitial atom in the irradiated material, which is widely utilized by Norgertt-Robinson-Torrens (NRT) model[6]
For estimation of target materials used at high-intensity proton accelerator, displacement cross section experiment was carried out in J-PARC

Summary

Introduction

To decrease hazard of the radioactive waste produced in a nuclear reactor, Japan Atomic Energy Agency (JAEA) proposes the Accelerator Driven System (ADS) with extremely high power accelerator such as 30 MW with proton kinetic energy of 1.5 GeV. In the design of the ADS, damage to the beam intercepting material is one of a critical issue. In other high-intensity accelerator facilities, beam intercepting material plays essential roles. At Material Life science experimental Facility (MLF)[1, 2] in J-PARC[3], an aluminum alloy is utilized as beam window[4] separating between high vacuum area and target station. To operate high power accelerator with confidence, damage estimation of the target material is essential. For the quantitative specification of the damage to the target material, displacement per atom (DPA) is employed in general. The DPA is widely used for the estimation of damage nuclear reactor and fusion reactor as well

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Discussion

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