Method of manufacturing coils for use in charged particle deflecting electromagnet

A method of manufacturing coils for use in charged particles deflecting electromagnets, each of said coils being formed by stacking a plurality of two-layer coil units, each of the two-layer coil units being formed by winding a conducting wire having a length corresponding to two layers such that two ends of the conducting wire having a length corresponding to two layers such that two ends of the conducting wire are located on an outer peripheral portion of the coil unit, said method comprising:

• forming the plurality of two-layer flat coils each of which has an inner diameter portion disposed on an inner diameter side of an arcuate path of charged particles, an outer diameter portion disposed on an outer diameter side of said path, and coil end portions located at two sides of said inner and outer diameter portions for connecting said inner and outer diameter portions with each other, said step of forming the two-layer flat coil including steps of forming a first layer flat coil by winding half of a single conducting wire having a length corresponding to the two layers from an intermediate portion of the wire outwardly from a reference point in one direction, and forming a second layer flat coil by winding the remaining portion of the conducting wire from the intermediate portion of the wire outwardly from the reference point in the other direction, said two steps of forming the first and second layer flat coils being repeated to form the plurality of the two-layer flat coils;
• forming two-layer coil units by bending the coil end portions of each of the two-layer flat coils in a direction opposite to said path such that they oppose each other;
• laying the plurality of two-layer coil units on top of another in a predetermined order;
• and
• electrically connecting ends of the conducting wires of the two-layer coil units which are laid with each other.