| 摘要 |
<p>A spark chamber 110 for an optical emission analyser comprises an elongated electrode 140 with axis 142. The top face of the chamber 110 accommodates a sample. A gas inlet 125 and gas outlet 135, preferably of rectangular shape, are located on opposite sides of the spark chamber 110, either side of the electrode 140. On passing along a gas flow axis 159 between the gas inlet 125 and the gas outlet 135 the unobstructed internal cross-sectional area of the spark chamber perpendicular to the gas flow axis remains constant to within a factor A, wherein A lies between 1.0 and 2.0. Preferably the spark chamber 110 is cylindrical in shape with curved walls and the electrode 140 lies on the axis of the cylinder. Preferably an insulator 150 surrounds the electrode 140 and has a shape parallel to the gas flow axis 159 to maintain a constant cross-section for the gas flow throughout the spark chamber 110.</p> |
