page_title: Ionization chamber
section_title: Research and calibration chambers
hierarchical_section_title: Ionization chamber / Chamber types and construction / Research and calibration chambers
caption_attribution_description: English: This device was developed by Curie (1859-1906) for radioactivity investigations. It includes a positive and negative plate connected by an electrometer, and the air within the chamber is ionised by radiation. The breakdown of air molecules into positive and negative ion pairs allows them to act as carriers of electric current. Negative ions migrate to the positive plate and positive ions to the negative plate, causing an electric current to flow. The level of radioactivity determines the current's strength.
context_page_description: The ionization chamber is the simplest of all gas-filled radiation detectors, and is widely used for the detection and measurement of certain types of ionizing radiation; X-rays, gamma rays, and beta particles. Conventionally, the term "ionization chamber" is used exclusively to describe those detectors which collect all the charges created by direct ionization within the gas through the application of an electric field. It only uses the discrete charges created by each interaction between the incident radiation and the gas, and does not involve the gas multiplication mechanisms used by other radiation instruments, such as the Geiger counter or the proportional counter.
  Ion chambers have a good uniform response to radiation over a wide range of energies and are the preferred means of measuring high levels of gamma radiation. They are widely used in the nuclear power industry, research labs, radiography, radiobiology, and environmental monitoring.
context_section_description: Early versions of the ion chamber were used by Marie and Pierre Curie in their original work in isolating radioactive materials. Since then the ion chamber has been a widely used tool in the laboratory for research and calibration purposes. To do this a wide variety of bespoke chamber shapes, some using liquids as the ionized medium, have been evolved and used. Ion chambers are used by national laboratories to calibrate primary standards, and also to transfer these standards to other calibration facilities.
caption: Ionization chamber made by Pierre Curie, c 1895-1900
exif: {"Image ImageWidth": "2858", "Image ImageLength": "3504", "Image BitsPerSample": "[8, 8, 8]", "Image PhotometricInterpretation": "2", "Image ImageDescription": "This device was developed by Curie (1859-1906) for radioactivity investigations. It includes a positive and negative plate connected by an electrometer, and the air within the chamber is ionised by radiation. The breakdown of air molecules into positive and negative ion pairs allows them to act as carriers of electric current. Negative ions migrate to the positive plate and positive ions to the negative plate, causing an electric current to flow. The level of radioactivity determines the current's strength.", "Image Orientation": "Horizontal (normal)", "Image SamplesPerPixel": "3", "Image XResolution": "1499753/5000", "Image YResolution": "1499753/5000", "Image ResolutionUnit": "Pixels/Inch", "Image Software": "Adobe Photoshop CS6 (Macintosh)", "Image DateTime": "2013:08:28 15:11:55", "Image Artist": "Science Museum", "Image Copyright": "Please read our licence terms.  All digital images must be destroyed unless otherwise agreed in writing.", "Image ExifOffset": "904", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail XResolution": "72", "Thumbnail YResolution": "72", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "1054", "Thumbnail JPEGInterchangeFormatLength": "6183", "EXIF ExifVersion": "0221", "EXIF ColorSpace": "Uncalibrated", "EXIF ExifImageWidth": "1020", "EXIF ExifImageLength": "1250"}