Dielectric barrier discharge ionization detector and gas chromatography analyzer

A dielectric barrier discharge ionization detector comprising:

• a dielectric tube that defines a gas flow channel through which discharge gas flows, the dielectric tube extending in an axial direction;
• a high-voltage electrode provided on an outer wall of the dielectric tube;
• a ground electrode unit electrically grounded and provided on the outer wall of the dielectric tube;
• a voltage applicator connected to the high-voltage electrode, the voltage applicator applying an AC voltage across the high-voltage electrode and the ground electrode unit to cause discharge in the dielectric tube and to generate plasma from the discharge gas;
• a light source that emits excitation light to the discharge gas that flows through the dielectric tube;
• and
• an electric charge collection portion including a collection electrode that collects ions generated by light from the plasma, the ions being generated from a sample component in sample gas introduced in the gas flow channel, wherein
• the ground electrode unit includes a first ground electrode and a second ground electrode arranged at a distance from each other in an axial direction of the dielectric tube,
• the high-voltage electrode is provided between the first ground electrode and the second ground electrode,
• a first distance between the first ground electrode and the high-voltage electrode is shorter than a second distance between the second ground electrode and the high-voltage electrode,
• a cover is provided on the outer wall of the dielectric tube at a position between the first ground electrode and the high-voltage electrode, and
• the light source is arranged to emit, as being inclined with respect to a direction vertical to the axis direction of the dielectric tube, the excitation light such that an optical axis of the light source is directed toward a position where the cover is not provided on the outer wall of the dielectric tube.