The magnetic part for surge electric current suppression of acceleration power source and the surge electric current suppression circuit null of the acceleration power source which uses

摘要

A surge current-suppressing circuit for an accelerator comprising a magnetic device inserted between a high-voltage DC power supply and an ion source for suppressing surge current generated when electric charge stored in a stray capacitance existing between the high- voltage DC power supply and the load is released at the time of short- circuiting of the load. The magnetic device comprises a magnetic core constituted by interlaminar-insulated thin ribbons of an iron-base amorphous or fine crystalline soft magnetic alloy. The iron-base fine crystalline soft magnetic alloy has the composition represented by the general formula: PP(Fe.sub.1-a M.sub.a).sub.100-x-y-z- &agr; Cu.sub.x Si.sub. y.sub.B.sub.z M'.sub.&agr;PP wherein M is Co and/or Ni, M' is at least one element selected from the group consisting of Nb, W, Ta, Zr, Hf, Ti and Mo, and a, x, y, z and &agr; respectively satisfy 0. ltoreq.a≦0.5, 0.1≦×≦3, 0≦y≦ 30, 0. ltoreq.z≦25, 5≦y+z≦30 and 0.1≦&agr;≦ 30, at least 50% of the alloy structure being fine crystal grains made of a bcc Fe solid solution having an average crystal grain size of 1000Å or less when determined from a maximum size of each crystal grain.