What type of dosimetry is used to measure the external radiation dose received from sources?

The type of dosimetry that effectively measures external radiation doses is Thermoluminescent Dosimetry (TLD). TLDs work by using materials that absorb energy from ionizing radiation. When heated, these materials release that stored energy as light, which can be quantified to determine the amount of radiation exposure. This method is particularly effective for measuring doses received over a period of time due to its sensitivity and ability to be reused after appropriate processing.

Film badge dosimetry also measures external radiation but relies on the darkening of film, which can be less sensitive compared to TLDs over extended exposure periods. Scintillation dosimetry involves detecting radiation through scintillation materials that emit light when exposed to radiation, primarily used for higher dose rate applications or for specific types of radiation detection rather than comprehensive external dosimetry. Ionization chambers can measure radiation doses directly, but they are typically used for real-time measurements in a laboratory setting rather than for personal dosimetry. Therefore, TLDs are preferred in personal dosimetry for their reliable and accurate measurement of external radiation doses.