tailieunhanh - Radiation and Health - Chapter 6

Trong chương này, các thiết bị và phương pháp được sử dụng để đo lường bức xạ ion hóa sẽ được thảo luận. Có hai loại dụng cụ: các thiết bị đếm (được sử dụng để xác định số becơren và chất lượng bức xạ) và Liều kế được sử dụng để xác định liều bức xạ. Cả hai loại thiết bị yêu cầu kết quả phóng xạ thay đổi quan sát được trong một hợp chất (hay không khí, chất lỏng hoặc rắn). Thiết bị đo lường bao gồm hai bộ phận thường được kết nối. Phần đầu tiên. | Chapter 6 The Measurement of Radiation Introduction In this chapter the equipment and methods used for measuring ionizing radiation will be discussed. There are two types of instruments counting equipment used to determine the number of becquerels and the radiation quality and dosimeters used to determine the radiation dose . Both types of equipment require that the radiations result in observable changes in a compound whether gas liquid or solid . Measuring equipment consists of two parts that usually are connected. The first part consists of a sensitive volume consisting of a compound that experiences changes when exposed to radiation. The other component is a device that converts these changes into measurable signals. The qualities of radiation that we want to measure are Activity. The activity or strength of a source is measured in becquerel. The concentration is usually given in Bq kg solid or Bq m3 liquid or gas . In considering pollution of an area Bq m2 is used. Some countries still use Ci km2. Type of radiation. It is important to distinguish between a- or P-particles x- or Y-rays and neutrons. Energy. The energy is usually measured in the unit electron volt eV . The energy of the particles or photons is important. 2003 Taylor Francis 48 Radiation and Health Dose is the absorbed radiation energy. Note that the absorbed energy is different from the energy of the emitted particles see above . The preferred unit is the gray. Measuring equipment can vary in size and price. The equipment chosen depends on the purpose of the measurement the sensitivity desired and the precision necessary. The simplest type of measurement is to observe the amount of radiation hitting the sensitive volume or detector of the counter. If the sensitive volume is covered with plates of different thicknesses and composition information may be obtained on the type of radiation. These instruments may be used to monitor radiation areas. Exact measurements of radiation energy are more .