Ion generator and ion implanter

An ion generator comprising:

• an arc chamber which defines a plasma generation space;
• a cathode which emits thermoelectrons toward the plasma generation space;
• and
• a repeller which faces the cathode with the plasma generation space interposed therebetween,
• wherein the arc chamber includes a box-shaped main body which includes an opening in at least a part of a front side of the main body, and a slit member which is mounted to cover the opening of the front side of the main body and provided with a front slit for extracting ions,
• an inner surface of the main body which is exposed to the plasma generation space is made of a first refractory metal material,
• the slit member includes an inner member made of graphite, and an outer member made of a second refractory metal material,
• the outer member includes an outer surface which is exposed to an outside of the arc chamber, and
• the inner member includes an inner surface which is exposed to the plasma generation space and an inner opening which forms the front slit extending from the inner surface of the inner member to the outer surface of the outer member.