Inserting the factor lcos 81 into Eq. The factor 1 is obtained as the ratio of Eq. What is the photon energy range corresponding to the UV radiation band? The following set of count readings was made in a gradient-free y-ray field, using a suitable detector for repetitive time periods of one minute:
|Published (Last):||23 May 2004|
|PDF File Size:||3.92 Mb|
|ePub File Size:||16.86 Mb|
|Price:||Free* [*Free Regsitration Required]|
Inserting the factor lcos 81 into Eq. The factor 1 is obtained as the ratio of Eq. What is the photon energy range corresponding to the UV radiation band? The following set of count readings was made in a gradient-free y-ray field, using a suitable detector for repetitive time periods of one minute: The flux density decreases with increasing distance from a point source of rays as the inverse square of the distance.
The strength of the electric field sur- rounding a point electric charge does likewise. At a point midway between two identical charges the electric field is zero. In problem 5, what is the energy fluence of 1. A train goes by at 60 miles per hour. Ignoring scattering and attenuation, what is the fluence of neutrons that would strike a passenger at the same height above the track as the source?
An x-ray field at a point Pcontains 7. What is its standard deviation S. What is the theoretical minimum S. What is the actual S. What is the flux density midway between two identical sources? What is the essential difference between the two cases? What is the photon flux density at P? What would be the photon fluence in one hour? Twice that due to one of the sources. Flux density is a scalar quantity; electric field strength is a vector.
Vector addition depends on orientation; scalar addition does not. From Eq. INTRODUCTION In Chapter 1 we discussed how a field of ionizing radiation could be described non- stochastically in terms of the expectation value of the number of rays, or of the energy they carry, striking an infinitesimal sphere around the point of interest. In this chap- ter we will define three nonstochastic quantities that are useful for describing the interactions of the radiation field with matter, also in terms of expectation values for the infinitesimal sphere at the point of interest.
These quantities are a the kenna K, describing the first step in energy dissipation by indirectly ionizing radiation, that is, energy transfer to charged particles; b the absorbed dosc D, describing the energy imparted to matter by all kinds of ionizing radiations, but delivered by the charged particles; and c the exposure, X, which describes x- and y-ray fields in terms of their ability to ionize air.
A more detailed discussion of w will be delayed until Chapter Finally, some additional quantities relevant to radiation protection will be briefly discussed. A word about neutrinos is required with respect to the following definitions, to avoid confusion in Chapter 4 when we deal with equilibria. Neutrinos are elementary particles having no electric charge and practically zero mass, hence they have an exceedingly small cross section for interacting with matter.
Terms in the following definitions that refer to indirectly ionizing radiation could include neutrinos, since they are uncharged, but t will be arbitrarily 20 The rest mass conversion tmm C Q likewise will ignore mass-energy transactions with neutrinos. Actually the definitions in the present chapter are valid whether or not one ex- cludes neutrinos, but consideration of equilibria in Chapter 4 will be much simpler and more practical if the neutrinos are ignored; hence we will do so from now on.
No error results from this. KERMA This nonstochastic quantity is relevant only for fields of indirectly ionizing radiations photons or neutrons or for any ionizing radiation source distributed within the absorbing medium. Definition The kerma K can be defined in terms of the related stochastic quantity energy transferred, etr Attix, , and the radiant energy R ICRU, By radiative losses, we mean conversion ofcharged-particle kinetic energy to pho- ton energy, through either bremsstrahlung x-ray production or in-flight annihilation of positrons.
In the latter case only the kinetic energy possessed by the positron at the instant of annihilation which is carried away by the resulting photons along with 1. Radiant energy R is defined as the energy of particles excluding rest energy emit
Autoreninfo A new, comprehensively updated follow-up to the acclaimed textbook by F. Attix Introduction to Radiological Physics and Radiation Dosimetry taking into account the substantial developments in dosimetry since its first edition. This monograph covers charged and uncharged particle interactions at a level consistent with the advanced use of the Monte Carlo method in dosimetry; radiation quantities, macroscopic behaviour and the characterization of radiation fields and beams are covered in detail. A number of chapters include addenda presenting derivations and discussions that offer new insight into established dosimetric principles and concepts. The theoretical aspects of dosimetry are given in the comprehensive chapter on cavity theory, followed by the description of primary measurement standards, ionization chambers, chemical dosimeters and solid state detectors. Chapters on applications include reference dosimetry for standard and small fields in radiotherapy, diagnostic radiology and interventional procedures, dosimetry of unsealed and sealed radionuclide sources, and neutron beam dosimetry. The topics are presented in a logical, easy-to-follow sequence and the text is supplemented by numerous illustrative diagrams, tables and appendices.
Introduction to radiological physics and radiation dosimetry
Fundamentals of Ionizing Radiation Dosimetry
Introduction to Radiological Physics and Radiation Dosimetry by Frank Herbert Attix 1986.pdf