Orthogonal acceleration time-of-flight mass spectrometer and lead-in electrode for the same

A lead-in electrode of an orthogonal acceleration time-of-flight mass spectrometer, the lead-in electrode comprising:

• (a) a main body having a plate shape, the main body having an ion passing part;
• (b) a first member which is a plate-shaped member in which there is provided a main-body accommodating part which is a through-hole and accommodates the main body, wherein on one surface of the first member there is provided an extension part to delimit a position of one surface of the main body accommodated in the main-body accommodating part;
• (c) a second member which is a plate-shaped member and is to be attached to the first member accommodating the main body in the main-body accommodating part, wherein a through-hole is provided at such a position of the second member that at least a part of the ion passing part is not blocked, and on one surface of the second member there are formed a first area which is in contact with a surface opposite to the one surface of the first member and a second area which is located inside with respect to the first area and is formed lower than a surface, of the first area, in contact with the surface opposite to the one surface of the first member;
• and
• (d) an elastic member disposed, in the second area, between the main body and the second member.