A radiation detector for detecting the axial position of radiation incident to a scintillation element. Roughened surface portions are selectively configured and interstitially positioned relative to mirror-polished surface portions at discrete intervals along the axis of the element for optimizing the position resolution by varying the light reflection characteristics of the element.

Process of and apparatus for the simultaneous determination of the concentration of a plurality of radioactive gases. Radioactive gas containing several beta radionuclides is led into a separate chamber where their concentration is determined simultaneously and selectively by using a plastic multi-layer scintillator. The energy of the emitted beta radiation further identifies single radionuclides, and it determines them selectively and quantitatively by carrying out an amplitude discrimination of the registered impulses. The process can be carried out continuously or discontinuously. The multi-layer scintillation chamber is composed of a light-tight casing in which plates of plastic scintillators having suitable dimensions and location are placed in spaced relationship, such plates being connected on each end of the casing with a photomultiplier through a light-guide.

Structures for containing and supporting scintillator bodies are disclosed in which the optical output of the scintillator body is channeled by light reflective means to photoelectrically responsive devices mounted on the top and bottom of the detector array. In accordance with one embodiment of the invention, the internal surfaces of the collimating array are coated with either a diffuse or specular reflective coating. In accordance with another embodiment of the invention, the photoelectrically responsive transducers are located at the top and bottom of the array rather than at the rear. In accordance with another embodiment of the invention, reflective light channeling wedges are provided to improve spacing requirements for the photoelectrically responsive transducers. The scintillator structures of the present invention provide superior optical coupling to photoelectrically responsive devices.

A radiation detection device including a scintillation crystal in the form of a rod having photomultiplier devices affixed to either end which monitors the X-ray transmission characteristics of an object. Associated circuitry responds to the output signals developed by the photomultiplier tubes to map the transmission characteristics of the object. The use of a single rod-like scintillation crystal in combination with a pair of photomultiplier devices replaces the array of discrete simulator scintillation crystals typically employed to monitor objects for radiation emitting materials.

A gamma camera having a scintillation detector formed of multiple bar detector modules. The bar detector modules in turn are formed of multiple scintillation crystal bars, each being designed to have physical characteristics, such as light yield, to achieve a sufficient spatial resolution for nuclear medical imaging applications. According to another aspect of the invention, the bar detector modules are arranged in a three-dimensional array, where each module is made up of a two-dimensional array of bar detectors with at least one photosensor optically coupled to each end of the module. Such a camera can be used for both PET (coincidence) and single photon imaging applications. According to another aspect of the invention, a bar detector gamma camera is provided, which utilizes an improved positioning algorithm that greatly enhances spatial resolution in the z-axis direction (i.e., the direction along the length of the scintillation crystal bar).