ThePhysicsofRadiology-chapter1-2 放射物理 英文版 教学课件.pptVIP

ＴＨＥ　ＰＨＹＳＩＣＳ　ＯＦ　ＲＡＤＩＯＬＯＧＹ ＢＡＳＩＣ　ＣＯＮＣＥＰＴＳ ＰＡＲＴ　TWO Atoms Matter is composed by atoms Structure of Atoms nucleus----radius 10-14m electrons clouds----radii 10-10m Atomic number: Z number of electrons chemical properties Nucleus Constitution protons neutrons Q: How to know the structure of the nucleus? Q: Properties of protons and neutrons: charge and mass mass number: A protons + neutrons neutrons = A-Z Nucleus Isotope definition: Atoms composed of nuclei with the same number of protons but different number of neutrons are called isotopes. stable or unstable ; disintegration and radioactive; Atomic Mass Elemental particles p—proton 1.007277, +1 The proton is the nucleus of the hydrogen atom. The hydrogen atom consists of 1 proton in the nucleus and 1 external electron. The mass of the neutral atom is 1.007277 +0.000548 = 1.007825 mass units. The proton is one of the fundamental building blocks of all nuclei. Beams of protons are being used in radiotherapy. Elemental particles n—neutron 1.008665, 0 The neutron is the other fundamental building block of all nuclei. Neutrons have nearly the same mass as protons. Since the neutrons is an uncharged particle it is hard to stop and difficult to detect. Beams of neutrons are being used in radiotherapy. Elemental particles Elemental particles Elemental particles Elemental particles Elemental particles Elemental particles Elemental particles p—proton 1.007277, +1 n—neutron 1.008665, 0 Extranuclear structure Extranuclear structure—chemical properties The outermost orbit Chemical properties and valence repeat inert gas : He, Ne, … alkaline elements: lithium, sodium,… Atomic Energy levels Nuclear Energy levels Quantum nature of radiation Quantum nature of radiation Electromagnetic Spectrum Electromagnetic Spectrum Electromagnetic Spectrum Electromagnetic Spectrum Electromagnetic Spectrum Electromagnetic Spe