The human senses cannot detect radiation, but a variety of portable and laboratory instruments are available for detecting and measuring it. There are several methods and equipment used to detect radiation, such as film badges, gas ionization devices, Geiger-Muller counters, radon detectors, personal radiation detectors, fog chambers, and scintillation counters. Radiation dosimetry is the most common example of this, with radiation badges used by medical personnel, workers in the nuclear industry, and many other workers exposed for work reasons around the world. Alpha radiation cannot be detected because it is blocked by the mobile phone case, lens and cover. An RIID is a radiation detector with the ability to analyze the energy spectrum of radiation, in order to identify the specific radioactive material (radionuclide) that emits the radiation.
Smartphones that have CMOS cameras have been widely adopted around the world, making them potentially useful as tools for monitoring radiation in cases of civil emergencies, such as the Fukushima disaster, or more mundane situations, such as exposure to radiation while traveling in an airplane. Complementary metal oxide semiconductor (CMOS) imaging sensors used in smartphone cameras can detect photons of ionizing radiation, such as high-energy x-rays and gamma rays. These sensors range from large cloud cameras to personal portable devices. An error analysis quantitatively shows that a smartphone application called RadioActivityCounter can effectively function as a radiation detector at high radiation doses; however, at low doses, the application returns a high error percentage. Since the early days of radiation testing conducted by Roentgen and Becquerel, scientists have been looking for ways to measure and observe the radiation emitted by the materials they worked with. Advanced image sensors installed in now-ubiquitous smartphones can be used to detect ionizing radiation in addition to visible light.
Nor should the response of an ionizing radiation detector depend on the angle of impact of the radiation. When talking about radiation detection instruments, there are three types of detectors that are most often used depending on the specific needs of the device. Radiation can be used in a variety of applications, and approximately 23 million workers are exposed to ionizing radiation worldwide. A particular meter known as a teletector is specifically designed to detect gamma and x-ray radiation.