Radiochromic film

The film contains a dye which changes colour when exposed to ionising radiation, allowing the level of exposure and beam profile to be characterised.

[1] Unlike x-ray film no developing process is required and results can be obtained almost instantly, while it is insensitive to visible light (making handling easier).

[2] The active layer consists of polycrystalline, substituted-diacetylene and the colour change occurs due to "progressive 1,4-trans additions as polyconjugations along the ladder-like polymer chains".

[4] Unlike many other types of radiation detector, radiochromic film can be used for absolute dosimetry where information about absorbed dose is obtained directly.

[3] It is typically scanned, for example using a standard flat bed scanner, to provide accurate quantification of the optical density and therefore degree of exposure.