A PRIMER OF APPLIED RADIATION PHYSICS pot

[...]... and magnetic radiation on the basis of the parity change, An Electric radiation corresponds to a change of (-1) e and magnetic radiation to -(-I) Thus, for a transition between levels in which there is no change in parity, c can only be 0 or even for electric radiation and odd for magnetic radiation An approximate relation between the energy of electric radiation and the probability of its emission... equipotential planes accelerator tube exit window A Fig.(l.9) The main features of a Van de Graaff generator Corona points connected to the positive terminal of a dc power supply attract negative charge from a flexible insulating belt, rendering it positive Because the belt is insulating, the charges remain in place and are carried upwards towards a similar set of corona points in the centre of a hollow... photons Radioactivity orthovoltageX-rays kV X-rays Iinaclbetatron MV X-rays, electrons and radioactivity Van de Graaff and Cyclotron protons, neutrons and radioactivity Synchrotron electrons, protons, X-rays, uv photons Nuclear Reactor Artificial a- and p- particles, y-rays, neutrons neutrons, y-rays, residual radioactivity The minimum requirementsfor a full understandingof radiation action are : 0 0... features known as the polar horns and the South Atlantic anomaly 1.3 Radioactive Sources Radioactive decay is the process by which a nucleus in an unstable state is able to SOURCES OF RADIATION 4 achieve greater stability by emitting a particle or photon The probability per second that the emission takes place is the decay constant If there are Nonuclei present originally (at time t = 0), then at a. .. extent, and produce X-rays in the terminal structure very efficiently SOURCES OF RADIATION 16 The effect constitutes a radiation protection problem near the terminal end of all positive ion Van de Graaff generators Tandem acceleration In a conventional single-stage accelerator, the ion source is located within the high voltage terminal Particles can be accelerated to double the terminal potential (although... In addition, there will be a ripple AV on the output voltage In AV = - N + 2 ) N( 8 C w From Eq.(l.14) it is seen that large terminal potentials are produced with large values of C and o and a small I These conditions also result in a small ripple, AV, once the optimum number of stages has been determined 1.4.2 Van de Graaff generator The electrostatic charging of a metallic sphere takes place by means... 80% of the radiation exposure of the UK population Of this, a- particle emissions from atmospheric radon are by far the most important Some building materials contain long-lived actinide elements in small quantities while traces of naturally occurring isotopes (40K 12C)are present in all and of us More detailed figures are given in Chapter 11 RADIOACTIVE SOURCES 3 Cosmic Rays 1.2 Cosmic rays span a very... 3 + At higher altitudes the very high ffuxes of energetic charged particles, Fig (1 I), may well affect the instrumentation requiredfor satellite and space exploration These cosmic rays are both galactic and solar in origin, the latter showing a variation due to the occurrence of solar flares Galactic and solar cosmic rays are affected by the earth's magnetic field This gives rise to the radiation. .. Neutron activation analysis (NAA) 278 8.4.5 Effects of self-absorption in NAA 279 8 8.4.6 Effects of energy-dependentcross-sections in NAA 2 1 Irradiation by Charged Particles 283 A Practical Example - The Proton Irradiation of Natural Copper .285 CHAPTER 9 : RADIOTHERAPY 91 Introduction 289 9 2 Photons 290 Geometrical factors 292 9.2.1 Specification of dose ratios... protons pass through low pressurehydrogen gas, the emerging particles consist mainly of protons, with small quantities of neutral hydrogen atoms and even smaller quantities of H- ions These can be separated magnetically and the H-acceleratedtowards the high positive terminal potential When they reach this high energy, and are passed through a similar low pressure gas (or carbon foil), the probability of . Neutron activation analysis (NAA) 278 8.4.5 Effects of self-absorption in NAA 279 8.4.6 Irradiation by Charged Particles 283 A Practical Example - The Proton Irradiation of Natural. particularly thank John Barton, Ian Blair, Alan Edwards, Gerry Lowe, Seeni Naidu, Beate Planskoy, Robert Speller and Jane Taylor. Additional advice and data for some of the figures and tables. covered. In any case, imaging as a whole has a vast array of literature, with many excellent reviews already extant. The imaging chapter is therefore no more than a personal survey of selected