An operational amplifier capable of offset cancel in a shorter period, as well as a line driver capable of shortening one horizontal period and a liquid crystal display device are provided. The present invention primarily includes three housing components, namely an inner mounting die, an outer enclosure and an outer housing that cooperate to enhance the heat management of the overall assembly. The shelves have a top surface on which a specimen slide can rest, and a resilient bottom surface configured to pinch the slide below against the shelf below to frictionally retain the pinched slide in the cassette. A trapping field is generated within the collision cell so as to trap the ions within a trapping volume of the collision cell, the trapping volume being defined by the trapping field and extending along the longitudinal axis.