Abstract
Considering the stability of superconducting magnet which is irradiated by high energy pulse radiation in fusion reactor, the breaking and the recovering of superconducting state in short time (a few μsec) after pulse irradiation were investigated with short light pulse (8 and 30nsec) instead of high energy radiation. When current flowed in superconducting lead, voltage pulse was induced by irradiation and measured with a fast detection system of time resolution of about 10nsec. The observed decay time of the resistance agreed with the one which was evaluated from heat transfer equation. This indicates that the mechanism of breaking and recovering of superconducting state caused by this pulse irradiation was explained only by thermal effect.
