Efficiency calibrations of radiation detectors for source localization and characterization at long source-detector distances for gamma and neutron sources.

Deployment of radiation detectors under field conditions for the purposes of security, safety or response has increased in recent years. Effective use of such instruments in the field necessitates careful consideration of the efficiency of the detector - both peak and total - at distances which may extend beyond 100 m. Difficulties in addressing the determination of both peak and total efficiencies across the energy range of interest and at long distances reduces the utility of such systems in effectively characterising radiation sources in the field.

Misuse of a Medical Radioisotope: 125I Labeled Playing Cards in Germany, a Case Study.

The security of medical radioactive sources, both open and sealed, is an important consideration for reducing the risk of an intentional or inadvertent additional radiation dose to the public, according to the principle of keeping any additional radiation dose as low as reasonably achievable. The detection and following radiological investigation of the misuse of iodine-125 (I), a medically used radionuclide, in Germany is described in detail with the aim of sharing experience and raising awareness. The misuse of I shows that the security of I is not guaranteed completely at the present time.