Measurement of displacement cross section using 440-GeV protons at CERN HiRadMat

CERN HiRadMatにおける440GeV陽子を用いたはじき出し断面積測定

明午 伸一郎   ; 山口 雄司   ; 直江 崇   ; 渡邉 瑛介*; Lee, E.*; Domange, D.*; Gancarcik, D.*; Lannoy, C.*; Hemalsteens, C.*; Wollmann, D.*; Goillot, A. M.*; Charitonidis, N.*; Alexaki, P.*

Meigo, Shinichiro; Yamaguchi, Yuji; Naoe, Takashi; Watanabe, Eisuke*; Lee, E.*; Domange, D.*; Gancarcik, D.*; Lannoy, C.*; Hemalsteens, C.*; Wollmann, D.*; Goillot, A. M.*; Charitonidis, N.*; Alexaki, P.*

放射線による物質の損傷指標として、原子あたりはじき出し数(dpa)が広く用いられており、これは粒子フルエンスとはじき出し断面積によって与えられ、この断面積は、マティセン則により、陽子照射による標的物質の電気抵抗率変化から得られる。相対論的効果により単位体積あたりのエネルギー付与を増加させるため、440GeVなどの高エネルギー領域における実験的な断面積と計算モデルとの比較は興味深い。このためCERN HiRadMatで440GeV陽子を用いた実験を実施し、世界最高エネルギーとなる440GeV陽子のはじき出し断面積を測定した。

As a material-damage index due to the radiation, displacement per atom (dpa) is used widely, which is given by the particle fluence and the displacement cross section. The displacement cross section can be obtained by the electrical resistivity change of target materials due to the proton irradiation by the Matthiessen rule. The sample had to be cooled at cryogenic temperature to observe the very small resistivity change and sustain the damage. To obtain the cross section data, J-PARC and JAEA conducted experiments using protons in the kinetic energy range from 100 MeV to 120 GeV. It is of interest to compare the experimental cross section with the calculation model at high energy, such as 440 GeV/c, where relativistic effects increase energy deposition. To obtain the experimental data, an experiment at CERN HiRadMat using 440 GeV protons was conducted.