中性子散乱用真空槽内におけるLANケーブル

A pale yellow liquid was found in the vacuum scattering vessel which neutron detector is installed on BL02 spectrometer J-PARC MLF. The substance characterized as phthalic acids, are known plasticizers for poly(vinyl chloride) cable sheathing. leakage mechanism of needs to be urgently clarified, they contaminate and could cause background increase experimental data. We purchased commercially available LAN-cables evaluated damage sheaths based changes weight mechanical strength cables after gamma irradiation, treatment. results show that alpha, beta, or irradiation caused a local disruption polymer chains sheaths, depending extent disruption, other additives sheath leaked out. Polyimide-coated not currently available. However, polyimide were damaged by over short period time (about half day), indicating suitable candidate sheaths.