During the past few years, the technique of radiation characterization has undergone a rapid transformation. New materials of construction have made possible a number of improvements in conventional detectors, while several new detector types have been made available to the experimenter. Improvements in detectors have been accompanied by the development of more versatile and reliable electronic measuring equipment. Where once it was possible to record only the number of events in a certain detector, it is now quite common to record complicated spectral data. Many of the new techniques in nuclear data processing were inspired by progress in digital computer technology, which has resulted in a very desirable compatibility between modern nuclear equipment and digital computers. As a result, it now is possible to record and process information from a radiation detection system in a highly automated manner.
In writing this monograph, the author has tried to keep in mind the needs of those nuclear chemists who, because they are not trained in electronics, find themselves confused by the bewildering array ofequipment available for radiation measurement. The newcomer to the nuclear field is especially likely to need guidance in selecting a counting system appropriate to his needs. Therefore, it was felt that a review of the nuclear radiation detection problem was in order, with particular emphasis on new methods and their practical aspects. A description of the subject matter is given below.
It will be convenient to consider first the detector, in which the radiation interacts. Each type of detector will be discussed both in terms of its principle of operation and its applicability to various problems in counting and spectrometry. The most common detectors make use of one of the two main processes by which radiation transfers energy to a stopping material, i.e., excitation and ionization. In the detectors to be discussed, molecular dissociation is of small importance; however, this effect is the basis of the chemical dosimeters which find important applications in health physics.
