The primary device used to determine the wearer’s cumulative radiation exposure was the film badge. A film badge consisted of one or more small pieces of photographic-type film wrapped in a paper packet and enclosed in a plastic envelope or other special metal or plastic holder that could be clipped or otherwise attached to the wearer’s outer clothing. Film badges incorporated one or more special metal filters to improve performance. When processed, a film exhibited a darkening (net optical density) that is proportional to the cumulative radiation exposure. Optical density is measured with a densitometer and compared with a calibrated standard to determine total exposure. Film badges worn during the period of nuclear testing were primarily used to measure gamma radiation exposures. Some attempts (most unsuccessful) were made to measure beta radiation exposures, and special neutron film badges were employed during the later stages of the test program. The Nuclear Test Personnel Review (NIPR) program has located a considerable number of film badge dosimetry records, which have been entered into the master repository of dose records maintained by Reynolds Electrical & Engineering Company. As indicated by table 4, presented in section 1.5 of this report, the vast majority of doses were well below established radiation protection standards. The records attest to the effectiveness of the radiation protection efforts made during the atmospheric nuclear testing. Figure 17 shows a radiation monitor wearing protective clothing and using radiological safety equipment.* Table 9 provides a list of radiation detection and measurement instruments used for survey and personnel monitoring purposes. The list is not inclusive but identifies the instruments most commonly used. It is apparent that some instruments employed during an operation were replaced by improved equipment during subsequent operations. Other instruments, such as the MX-5, the TIB(AN/PDR-39), and the AN/PDR-27, were used (modified as necessary) for several years. 5.2.3 Protection Against Internal Doses. As mentioned earlier, procedures for protection against residual radi- ation had to consider internal doses resulting from inhalation and ingestion of radioactive material. Administrative controls that prohibited eating in *Army, Signal Corps Photograph, SC 435932. 146 17 March 1953.