H-type dipole model for future plan at KEK

For the bending magnet of the electron ring of the so-called TRISTAN project at KEK, the H-type dipole, full scale model with 4 m in length, has been investigated at first to examine the feasibility to the electron storage ring from some points such as magnet performance, accessibility for the field measurement and vacuum chamber installation, manufacturing problem and magnet cost. Here, the magnet performance is treated. To measure the magnetic field inside the air gap, the specially designed flip coils were used. Fields of 11 points at the same longitudinal positions could be measured at once by rotating probe containing 11 flip coils on its axis.