ionikammioon

Ionikammioon is the Finnish term for an ionization chamber, a gas-filled radiation detector used to measure ionizing radiation by collecting charge produced when radiation ionizes gas inside the chamber. The basic principle relies on creating ion pairs in the gas and collecting electrons and positive ions with an applied electric field between two electrodes. The measured current or collected charge is proportional to the rate of ionizing radiation within a defined operating range, making the device useful for dosimetry and monitoring.

Construction and operation: An ionikammio typically consists of a cavity filled with gas, a high-voltage electrode arrangement (parallel-plate or cylindrical geometry), and a metallic housing. The chamber can be sealed or vented to atmospheric pressure and may use air or noble gases as the fill gas. In medical physics and radiation protection, its response is calibrated to convert current to dose rate or total dose. Temperature and pressure influence gas density and are corrected in precise work.

Variants and applications: Common designs include parallel-plate and cylindrical ion chambers. They are favored for their wide linear range, stability, and simplicity. They are widely used in radiotherapy dosimetry, environmental monitoring, and nuclear instrumentation to detect gamma, X-ray, and charged particle fields. They are typically used for integrating dose over time rather than providing high-energy resolution.

Limitations: Ionikammioon performance depends on radiation quality, gas fill, and field strength; high dose rates can cause recombination. Energy dependence requires calibration for different radiation types.