Lecture20_NP1

Lecture20_NP1 - Nuclear Nuclear Physics 1 1 Topics Topics...

Info iconThis preview shows pages 1–11. Sign up to view the full content.

View Full Document Right Arrow Icon
Nuclear Physics 1 1
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Topics z Composition of the Nucleus z Ground State Properties z Nuclear Structure z Binding energy z Nuclear Models z Summary 2
Background image of page 2
Geiger, Marsden, Rutherford expt. z (Geiger, Marsden, 1906 - 1911) (interpreted by Rutherford, 1911) z get α particles from radioactive source z make “beam” of particles using “collimators” (lead plates with holes in them, holes aligned in straight line) z bombard foils of gold, silver, copper with beam z measure scattering angles of particles with scintillating screen (ZnS ) 3
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
4
Background image of page 4
Geiger Marsden experiment: result z most particles only slightly deflected (i.e. by small angles), ut some by large angles en backward but some by large angles - even backward z measured angular distribution of scattered particles did not agree with expectations from Thomson model (only small angles expected), z but did agree with that expected from scattering on small, ense positively charged nucleus with diameter 0 4 dense positively charged nucleus with diameter < 10 -14 m, surrounded by electrons at 10 -10 m Ernest Rutherford 1871-1937 5
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Composition of the Composition of the Nucleus Nucleus -- -- 1 From the experiments of Geiger and Marsden in 1911, it became clear that most of the mass of an atom is contained within a nucleus of size f 0 ~ 1 fm (= 10 -15 m ). 932 the eutron as discovered by Chadwick In 1932 , the neutron was discovered by Chadwick, the positron by Anderson and the first nuclear reaction with protons was observed by Cockcroft and Walton. 6
Background image of page 6
Composition of the Composition of the Nucleus Nucleus -- -- 2 A nucleus is a quantum system consisting of eutrons and protons held together by a rong neutrons and protons, held together by a strong nuclear force . A nucleus of a given species, called a nuclide , is defined by its atomic number Z , that is, by the number of protons it contains. N is the number of neutrons in the nucleus and A = N + Z is the mass number. For example, 15 O as A = 15 N =7andZ = 8 7 has A 15, N 7 and Z 8.
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Composition of the Composition of the Nucleus Nucleus -- -- 3 Neutrons and protons are referred to collectively ucleons 8 as nucleons .
Background image of page 8
Ground State Ground State Properties Properties -- -- 1 Nuclei with the same atomic number, but which differ in mass number, e.g., 15 O and 16 O are called isotopes . l examples: deuterium, heavy hydrogen 2 D or 2 H; heavy water = D O (0.015% of natural water) 2 U- 235 (0.7% of natural U), U-238 (99.3% of natural U), If nuclei have the same neutron number N, e.g., 3 d th ll d t 13 C and 14 N they are called isotones . hose with the same mass number e g 14 and 9 Those with the same mass number, e.g., C and 14 N are called isobars .
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Ground State Ground State Properties Properties -- -- 2 Nuclear Sizes – The size of nuclei can be inferred in many ways. One way is to use mirror nuclides : those with Z and N numbers switched, for l example: 15 15 87 ON 8p + 7n 7p + 8n
Background image of page 10
Image of page 11
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 02/17/2010 for the course PHY PHY3101 taught by Professor Prosper during the Spring '10 term at FSU.

Page1 / 31

Lecture20_NP1 - Nuclear Nuclear Physics 1 1 Topics Topics...

This preview shows document pages 1 - 11. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online