Ionization chamber

The utility model relates to an ionization chamber, which comprises a shell, a gas chamber, a gas inlet and a gas outlet, the high-voltage polar plate is arranged in the gas chamber; the collecting polar plate is arranged in the gas chamber and is opposite to the high-voltage polar plate at an interval; the collector plate is provided with a collector layer, and the collector layer comprises a first collection area and a second collection area which are insulated from each other; the size width of the first collection area in the first direction is smaller than or equal to; the second collecting area is annular and is arranged on the peripheral side of the first collecting area in a surrounding manner; the second collection area is larger than the first collection area. The size of one collecting area in the first direction is smaller than 20mm, so that the ionization chamber has higher resolution when moving upwards in the first direction for detection; the area of other collection areas is larger than that