A High Pressure Proportional Counter For Fast Neutron Spectroscopy

Gas-filled proton recoil proportional counters have been used extensively for the measurement of neutron spectra in degraded fission-spectrum environments. Some considerations relating to the use of these counters for personnel dosimetry are here described. High sensitivity and good accuracy in the determination of dose-equivalent can be obtained if relatively high pressure hydrogen-filled proportional counters are used as the active element in a dosimeter system.

NSA is a comprehensive collection of international nuclear science and technology literature for the period 1948 through 1976, pre-dating the prestigious INIS database, which began in 1970. NSA existed as a printed product (Volumes 1-33) initially, created by DOE's predecessor, the U.S. Atomic Energy Commission (AEC). NSA includes citations to scientific and technical reports from the AEC, the U.S. Energy Research and Development Administration and its contractors, plus other agencies and international organizations, universities, and industrial and research organizations. References to books, conference proceedings, papers, patents, dissertations, engineering drawings, and journal articles from worldwide sources are also included. Abstracts and full text are provided if available.

The largest daily fast neutron dose considered safe for the human body (tolerance dose) is taken to be 0.01 n units. If this dose is received during an 8 hour working day, The neutron flux has to be such as to provide an average dose rate of 0.01 n units per 8 hours. An instrument of high sensitivity is needed to measure fluxes of such order of magnitude in a reasonably short time and within a reasonably small space. High pressure ionization chambers as well as counters will serve the purpose. Which of the two should be chosen depends on what appears the most satisfactory compromise in fulfilling the following requirements: (1) The instrument should read as nearly proportional as possible to the biological effect, independently of the energy of the fast neutrons. (2) The instrument should have a high neutron to gamma sensitivity ratio, compared with the 100 r Victoreen chamber. (3) The instrument should be of rugged and simple construction and require no accessories that would make the total weight in excess of what is conveniently portable.

The Dosimetry of Ionizing Radiation, Volume II, attempts to fill the need for updated reference material on the field of radiation dosimetry. This book presents some broad topics in dosimetry and a variety of radiation dosimetry instrumentation and its application. The book opens with a chapter that extends and applies the concepts of microdosimetry to biological systems. This is followed by separate chapters on the state-of-the-art equipment and techniques used to determine neutron spectra; studies to determine recombination effects in ionization chambers exposed to high-intensity pulsed radiation; advances in water and polystyrene calorimetry; and beta-photon dosimetry for radiation protection. This book is clearly a valuable collection of work by outstanding authorities in their individual fields. It has an international flavor, with authors from England, Canada, and the United States. The quality of the work is equal to the best of what has been published in the past.